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2012 Poster Competition Winner Abstracts

Applied Science:

1st Place - Miranda Jones, PhD Candidate

Title: Secondhand tobacco smoke: an occupational hazard for smoking and non-smoking bar and nightclub employees

Background: Exposure to secondhand tobacco smoke is a major cause of respiratory, cardiovascular and cancer morbidity and mortality around the world. In the absence of comprehensive smoking bans in public places, bars and nightclubs have the highest concentrations of secondhand smoke, posing a serious health risk for employees in these venues.

Objective: To assess exposure of bar and nightclub employees to secondhand smoke, including non-smoking and smoking employees.

Methods: Between 2007 and 2009, we recruited approximately 10 venues per city and up to 5 employees per venue in 24 cities in the Americas, Eastern Europe, Asia and Africa. Air nicotine concentrations were measured for 7 days in 238 venues. To evaluate personal exposure to secondhand smoke, hair nicotine concentrations were also measured for 625 non-smoking and 311 smoking employees (N=936).

Results: Median (interquartile range [IQR]) air nicotine concentrations were 3.5 (1.5, 8.5) ?g/m3 and 0.2 (0.1, 0.7) ?g/m3 in smoking and smoke-free venues, respectively. Median (IQR) hair nicotine concentrations were 6.0 (1.6, 16.0) ng/mg and 1.7 (0.5, 5.5) ng/mg in smoking and non-smoking employees, respectively. After adjustment for age, sex, education, living with a smoker, hair treatment and region, a 2-fold increase in air nicotine concentrations was associated with a 30% (95% confidence interval 23%, 38%) increase in hair nicotine concentrations in non-smoking employees and with a 10% (2%, 19%) increase in smoking employees.

Conclusions: Occupational exposure to secondhand smoke, assessed by air nicotine, resulted in elevated concentrations of hair nicotine among non-smoking and smoking bar and nightclub employees. The high levels of airborne nicotine found in bars and nightclubs and the contribution of this exposure to employee hair nicotine concentrations support the need for legislation measures that ensure complete protection from secondhand smoke in these venues

2nd Place - Yue Guan, ScM Candidate

Title: Parental disclosure of G6PD and its relationship to child health in a Chinese population

Background: Glucose-6-phosphate deficiency (G6PD) is an X-linked enzyme deficiency that commonly manifests as food-induced or drug-induced acute hemolytic anemia but may lead to permanent neurological damage or death if inadequately managed. The challenges of preparing children to independently self-manage their condition are considerable, and health care professionals encourage parents to disclosing age-appropriate illness information to the affected child. Yet, little work has been undertaken to understand parental disclosure regards G6PD that may be related to better physical and psychosocial health of affected children.

Objectives: This study was designed to explore associated factors and patterns of parental disclosure of G6PD to an affected child and its relationship to child health.

Methods: A primary cross-sectional study of individual parents of 94 children affected with G6PD from Taiwan, Hong Kong and the mainland of China was conducted using paper or web-based survey instruments in Chinese. Socio-demographic characteristics, family history, exposure to G6PD health education and attitudes regarding G6PD were assessed along with parent-reported of the child’s age at disclosure and the extent of disclosure discussion for each of 9 key topics. Child health was assessed using the Chinese version of the Child Health Questionnaire-Parent Form (CHQ-PF28) and a 13-item G6PD symptom list.

Results:  44.7% of study children were reported to have experienced at least one clinically significant symptom of acute hemolytic anemia. Children with an anemia symptom history scored significantly lower on measures of physical and psychosocial health.  More extensive parental disclosure regarding G6PD was associated with better child health in both physical and psychosocial domains. Parental disclosure was positively associated with child age (r=0.19; p=0.04), sense of control of G6PD (r=0.22; p=0.02), positive emotions related to G6PD (r=0.23; p=0.01), and better quality of parent-reported G6PD education received from providers (r=0.37; p<0.001).

Conclusions: One of the modifiable factors found to be positively related to parental disclosure was the quality of G6PD education reported by parents to have been received from providers. This finding highlights opportunities for educational and behavioral interventions directed toward families and children with G6PD. Developing and testing the feasibility and effectiveness of interventions aimed to construct more accurate and positive illness representations of G6PD, facilitate parental disclosure to children and empower children to self-manage G6PD are important avenues for future research in assuring optimal child health.

Strengths of the Study: 1st study exploring health status of children with G6PD; 1st study exploring parents’ role in caring children with G6PD; Implications for children’s role in G6PD self-care.

Limitations of the Study: Conclusions cannot be drawn about causal pathways; Lack of documented clinical data and reliance on parental report of symptoms.

3rd Place - Megan Tschudy, MD Candidate

Title: Newborn Home Visitation: Teaching pediatric residents to extend the medical home into the community

Background: The scope of primary care has broadened with pediatricians addressing an increasing range of social and environmental issues. In vulnerable populations, home visits by have improved many child health indicators. No previous studies have examined pediatric resident change in knowledge, attitudes or behaviors after a home visit with a patient whom they have a longitudinal relationship.

Methods: A prospective cohort study was conducted between September 2009 and June 2010 in two outpatient clinics at an urban academic pediatric residency program in Baltimore, Maryland. The participants were residents who serve as primary care providers (n=32). Infants who received care in these clinics were recruited for a newborn home visit intervention. Residents completed an educational module about home visits and the community prior to the visit. They also completed a pre and post visit survey assessing knowledge of community, attitudes, and practice behaviors.  Comparison of pre and post intervention likert scores was made using a nonparametric Wilcoxon sign rank test.

Results: Post intervention residents had improved knowledge of the community, positively changed attitudes towards their patients, and clinical behaviors tailored better toward the patients and families they serve. There was a significant positive change (p < 0.05) in: adequacy of medical knowledge, not being concerned about safety, understanding of home and community, excitement about home visits, understanding that the home situation affects how one prescribes medicine and refers to subspecialists, and likelihood of making a future home visit. 39% percent reported a change in their views of how they should treat patients and 87% indicated home visits should be part of the permanent curriculum.

Conclusions: Conducting home visits was associated with residents’ improved understanding of the community, and home situation of their patients.  Residents felt home visits provided an important educational experience. Next steps will examine the impact of resident home visitation on family trust and healthcare utilization.

Basic/Lab Science:

1st Place - Wen-Hsuan Lin, PhD Candidate

Title: Viral Control and Immune Evasion in Measles Virus Infection: from Animal Experiments to Within-host Modeling

Measles virus (MeV) infection is a leading cause of vaccine-preventable childhood mortality worldwide. Infection with MeV induces both immune activation and immune suppression. The host immune response to MeV has been used as a paradigm for other acute or chronic viral infections. However, recent lines of evidence have suggested that the clearance of MeV is a prolonged and complicated process. We have investigated the in vivo process of MeV clearance by experimentally infecting 8 rhesus macaques with wild-type MeV and analyzing the virological and immunologic changes for 4 months. We found that MeV RNA persisted in the blood, respiratory tract or lymph nodes 4-5 times longer than infectious virus and was cleared in three phases. To identify host immune correlates to MeV clearance, we measured parameters related to immune suppression, MeV-specific T-cell and humoral activation using multiple assays. From these data, we identified an inverse correlation of viral load, foxp3 gene expression and the magnitude of MV-specific T cell response. To further examine the effect of individual host immune factors to the MeV load dynamics, we developed mathematical models for the process of within-host clearance of MeV RNA. More specifically, we fit the virus-load dynamics observed in these animals with models, which express viral replication and elimination in terms of the strength of MeV-specific IFNg-producing T-cell responses, antibody responses, target cell limitations and the immunosuppressive activity of regulatory T cells. Based on the model, we found that both MeV-specific T-cell and humoral responses contribute to controlling MeV replication in naïve animals and that suppression of the immune system might substantially slows viral clearance, and thereby contributes to the secondary peaks in virus load. These results have profound consequences for our understanding of acute viral infections, the development of prolonged immunity and, potentially, viral transmission. Here, we also provide a successful example for the study of in-host viral clearance that integrates biological measurements and mathematical modeling.

2nd Place - Mindy Graham

Title: Targeting the Human Androgen Receptor Gene with Platinum-Conjugated Triplex-Forming Oligonucleotides

Androgen receptor (AR) gene expression is required to maintain prostrate tumor cell growth, and inhibition of this gene would be expected to prevent prostate tumor cell proliferation. The human AR gene contains numerous homopurine tracts that can serve as binding sites for triplex-forming oligonucleotides (TFOs), a class of oligonucleotides that have significant potential as antigene agents. We have developed a novel type of TFO that is comprised of 2'-O-methylribonucleotides and contains a N7-trans-diamminechloroplatinumdeoxyguanosine residue at either its 5'- (Pt-mrTFO) or 3'-end (mrTFO-Pt). When bound to a homopurine tract in double-stranded DNA, the platinum group of the Pt-mrTFO can cross-link with suitably positioned guanine residues adjacent to the TFO binding site, a reaction that irreversibly anchors the TFO to its DNA target. Such cross-link formation would be expected to interfere with transcription and/or replication of the target DNA. We have identified 27 different homopurine tracts in the transcribed region of the human AR gene whose sequences are compatible with cross-link formation by Pt-mrTFOs or mrTFO-Pt. In preliminary studies, we have synthesized a mrTFO-Pt whose sequence (mr-TTTCTTCTTTTCTCTCTTGPt; T = 2'-O-methylribothymine; C = 2'-O-methylribo-5-methylcytosine; GPt = N7-trans-diamminechloroplatinumdeoxyguanosine) targets a 19 nucleotide homopurine sequence located on the transcribed strand in the 2nd intron of the human AR gene. At physiological pH and temperature, the mrTFO containing deoxyguanosine derivatized with a non-reactive platinum group, diethylenetriamineplatinum(II), mr-TFO-Pt-i, forms a stable triplex (melting temperature = 69?C) with a 31 bp DNA duplex containing the target homopurine sequence found within the AR gene. The reactive mrTFO-Pt cross-links to this duplex to the extent of 80% under physiological conditions as shown by gel electrophoretic mobility shift assays. To test its ability to inhibit transcription, the mrTFO-Pt was cross-linked to a firefly luciferase reporter plasmid that contained a single copy of the AR target gene sequence placed in the transcribed region between the plasmid's CMV promoter and luciferase reporter gene. The cross-linked plasmid was co-transfected with a Renilla luciferase reporter plasmid (to monitor transfection efficiency) into AA8 cells in culture and luciferase activity was determined 24 hrs after transfection using a dual luciferase assay (Promega Inc.). Luciferase expression decreased 96% compared to that from a non-cross-linked control plasmid. The mrTFO-Pt was found to be resistant to degradation when incubated at 37?C for a period of 24 hrs with cell culture medium containing 10% fetal calf serum.  Transfection of a human prostate cancer cell line (LAPC4) with a Lipofectamine complex of the 5'-fluorescein-labeled mrTFO-Pt-i resulted in nuclear localization of the label in 69% of the cells as revealed by fluorescence microscopy of the live cells.  The ability of the mrTFO-Pt to cross-link effectively with its target, and inhibit DNA transcription suggests that these compounds may have potential as therapeutic agents to disrupt AR signaling in androgen-resistant prostate cancer.

3rd Place - Andrew Jaffe

Title: Bump Hunting in Genomics Data from Large Epidemiological Studies

During the last five years, high-throughput technologies have been successfully used by epidemiology studies, but almost all have focused on sequence variation through genome-wide association studies [GWAS]. Today, the study of other genomic events is becoming more common in large-scale epidemiological studies. Many of these, unlike the single nucleotide polymorphism studied in GWAS, are continuous outcomes. In this context, the exercise of searching for regions of interest is akin to the problems described in the statistical “bump hunting” literature. New statistical challenges arise when the measurements are continuous rather than categorical, when they are measured with uncertainty, and when both biological signal, and measurement error are characterized by spatial correlation along the genome. But perhaps the most challenging complication is that data from large studies are collected through-out long periods making it susceptible to “batch effects”. An example that combines all three characteristics is genome-wide DNA methylation measurements. Here, we present a data analysis pipeline that effectively models measurement error, removes batch effects, detects regions of interest, and attaches statistical uncertainty to reported regions. We illustrate the usefulness of our approach by detecting genomic regions of DNA methylation associated with a continuous trait in a well-characterized population of newborns. Our framework offers a comprehensive yet flexible approach for identifying general regions of biological interest in large epidemiological studies.

2011 Poster Competition Winner Abstracts

Applied Science:

1st Place- Applied Science Winner: Andrea Christman, PhD Candidate

Title: Hyperglycemia Does Not Add to Diabetes Status in Predicting Cognitive Decline: Results from the Atherosclerosis Risk in Communities (ARIC) Study

Introduction: Diabetes is associated with an increased risk of cognitive decline and dementia. It is unclear if hyperglycemia is an independent predictor of cognitive decline in persons with and without diabetes.

Hypothesis: We hypothesized that hyperglycemia, as assessed by glycated hemoglobin (HbA1c), would be positively associated with decline in cognition in persons with and without diabetes.

Methods: Prospective cohort study of 516 participants with and 8,442 without a history of diagnosed diabetes in the ARIC Study. We examined the association of categories of HbA1c (<5.7, 5.7-6.5, ?6.5% in nondiabetics; <7, 7-8, ?8% in diabetics) with 6-year change in three measures of cognition: the Digit Symbol Substitution Test (DSST), Delayed Word Recall Test (DWRT), and Word Fluency Test (WFT). Our primary outcomes were the quintile with the most annual cognitive decline for each test.

Results: Mean age was 56 years; the participants were 56% female and 21% African American. Mean HbA1c was 5.7% overall, and 8.5% in persons with and 5.5% in persons without diabetes. In adjusted logistic regression models, diagnosed diabetes was associated with cognitive decline only as assessed by DSST (OR 1.42, 95% CI (1.14, 1.75), p = 0.002), but HbA1c was not a significant independent predictor of cognitive decline when stratifying by diabetes history (diabetes, p-trend = 0.320; no diabetes, p-trend = 0.566). Similarly, trends were not significant for the DWRT or WFT in either the presence or absence of diabetes.

Conclusions: Over 6 years of follow-up, we found that hyperglycemia, as measured by HbA1c, did not predict cognitive decline beyond diabetes status in this middle-aged, community-based population. These findings are consistent with recent clinical trial data demonstrating that tight glycemic control does not prevent cognitive decline in diabetes. In conclusion, additional work is needed to identify the non-glycemic risk factors by which diabetes may contribute to cognitive decline.

Table. Adjusted* Odds Ratios (95% Confidence Interval) for Top Quintile of Yearly Cognitive Decline.


Digit Symbol Substitution Test

Delayed Word Recall Test

Word Fluency Test

Diagnosed Diabetes (Yes vs. No)

1.42 (1.14, 1.75)

1.13 (0.91, 1.41)

1.20 (0.96, 1.50)

No Diabetes




     HbA1c<5.7

1.00 (ref.)

1.00 (ref.)

1.00 (ref.)

     HbA1c 5.7-6.5

0.94 (0.81, 1.09)

0.90 (0.77, 1.04)

0.95 (0.82, 1.10)

     HbA1c?6.5

0.94 (0.69, 1.26)

1.30 (1.00, 1.71)

0.99 (0.73, 1.33)

P-Value for Trend

0.566

0.462

0.589

Diagnosed Diabetes




     HbA1c<7.0

1.04 (0.69, 1.57)

1.01 (0.67, 1.52)

0.93 (0.60, 1.43)

     HbA1c 7.0-8.0

1.78 (1.15, 2.74)

1.40 (0.90, 2.16)

1.41 (0.90, 2.22)

     HbA1c?8.0

1.34 (1.00, 1.81)

1.08 (0.80, 1.46)

1.22 (0.90, 1.66)

P-Value for Trend

0.320

0.612

0.190

P-Value for Overall Trend

0.011

0.235

0.169

*Adjusted for age, race, sex, education, income, field center, smoking, drinking, body mass index, systolic and diastolic blood pressures, hypertension medication use, LDL- and HDL cholesterol, and triglycerides.


2nd Place- Cari Meinhold Kitahara, PhD Candidate

Title: Obesity and Thyroid Cancer Risk

Background: Thyroid cancer incidence has risen dramatically in the U.S. since the early 1980s.  Although the prevalence of obesity has doubled during this time period, the relationship between obesity and thyroid cancer is uncertain. 

Methods: We examined the association between body mass index (BMI) and thyroid cancer risk in a pooled analysis from five prospective U.S. studies, including 413,979 women and 434,953 men.  Original data from each study were categorized using standardized exposure, covariate, and outcome definitions.  Proportional hazards models with attained age as the time metric were adjusted for education, race, marital status, smoking, alcohol intake, and (where appropriate) cohort and sex. 

Results: Over follow-up (mean=10.3 years), 768 women and 388 men were diagnosed with thyroid cancer.  The risk of thyroid cancer was greater with increasing BMI (per 5 kg/m2: hazard ratio [HR] in women, 1.16 [95% confidence interval (CI), 1.08-1.24]; HR in men, 1.21 [95% CI, 0.97-1.49]).  There was no significant heterogeneity between studies (both P>0.05).  For women and men combined, the HRs for overweight (25.0-29.9 kg/m2) and obesity (?30 kg/m2) compared to normal-weight (18.5-24.9 kg/m2) were 1.20 (95% CI, 1.04-1.38) and 1.53 (95% CI, 1.31-1.79), respectively.  We found no significant effect modification by other factors, and the results did not differ significantly by histologic type.  A significant positive association for BMI in young adulthood (ages 18-20) with thyroid cancer risk was also observed (per 5-kg/m2 increase: HR, 1.18 [95% CI, 1.03-1.35]). 

Conclusion: These results provide strong evidence that obesity is an independent risk factor for thyroid cancer.

3rd Place- Jennifer Pearson, PhD Candidate

Title: Current and Former Smokers' opinions of potential tobacco regulatory actions by the FDA

The Surgeon General acknowledged the health risks associated with smoking in 1964; however, it was not until 2009 that the government claimed regulatory power over tobacco products with the Family Smoking Prevention and Tobacco Control Act. While the intent of the Tobacco Control Act is to reduce tobacco’s negative impact on the public’s health, the effect of this legislation on smokers’ attitudes, intentions, and behaviors is unclear. This study reports on characteristics of current and former smokers endorsing the following three FDA-related items: 1) Government regulation of cigarettes will make cigarettes safer; 2) The government should reduce the amount of nicotine in cigarettes to help smokers quit; and 3) Menthol cigarettes should be banned. A total of 3638 current and former smokers in 8 cities were surveyed, of which 432 were African American, 256 were Hispanic, and 249 were of another racial/ethnic background. Results indicate that 30% of current and former smokers believe that regulation with yield a safer cigarette. In all cases, former smokers were more supportive of FDA regulation than current smokers. Whites and African Americans vary considerably when asked if menthol should be banned (22% v. 34% p<0.001) and if nicotine should be reduced (53% vs. 67%, p<0.001). Multivariate results demonstrated that smokers who agreed that regulation would yield a safer cigarette were more likely to have graduated high school, feel social pressure to quit, and have a desire to quit. In comparison to smokers who disagreed that the government should decrease nicotine, smokers who agreed were more likely to be female, African American, intend to quit in the next 6 months, believe that smoking is a serious health risk, have a desire to quit, and feel social pressure to quit. Smokers who agreed that menthol should be banned were less likely to have graduated high school, and more likely to be African American, older, intend to quit in the next 6 months, want to quit smoking, and recently tried to quit. Findings suggest that smokers who are interested in quitting are open to government regulation of cigarettes.

Basic/Lab Science:

1st Place and Overall Winner- Sung-Jae Cha, PhD Candidate

Title: Targeting Plasmodium sporozoite-Kupffer cell interactions with a phage display library

After inoculation by the bite of an infected mosquito, Plasmodium sporozoites enter the blood stream and infect the liver with unique specificity. Previous evidence suggests that specific sporozoite-Kupffer cell interactions are required for liver invasion to occur but the molecular determinants of these interactions are unknown. By use of a phage display library we identified three peptides that bind to the surface of Kupffer cells. Importantly, these peptides strongly inhibited Plasmodium berghei sporozoite invasion of Kupffer cells in vitro and of the mouse liver in vivo. In a separate set of experiments we determined that antibodies against one of the peptides binds to the surface of sporozoites and protects mice from Plasmodium infection. The results suggest that the candidate peptides interact with specific Kupffer cell surface receptor(s) and structurally mimic sporozoite ligands of liver invasion. These findings may lead to the development of novel protective vaccines.

2nd Place- Eric Abston, PhD Candidate

Title: IL-33 Increases Inflammation and Impairs Heart Function During Viral Myocarditis

Rationale: Cardiovascular disease is the foremost cause of death in the U.S., accounting for 34% of all deaths in 2006.  The IL-33/ST2 axis has been identified as a signaling pathway of great importance in the progression of heart disease and the ST2 receptor is considered a biomarker for heart disease.  ST2 levels increase due to inflammation and mechanical strain associated with failing hearts.  IL-33 binds and activates ST2, which has been shown to be cardioprotective by reducing remodeling and improving function in models of heart injury.  However, IL-33/ST2 signaling can also enhance inflammation in autoimmune disease models.  Infectious myocarditis, which progresses to dilated cardiomyopathy (DCM) is an instance where both a prolonged inflammatory response with possible autoimmune involvement and heart injury and remodeling occur.   In a patient with infectious myocarditis, IL-33 could deleteriously promote inflammation, beneficially prevent heart remodeling and improve heart function, or both.  This study was designed to test the effect of increased IL-33 on the development of CVB3-induced myocarditis.

Methods: Exogenous rIL-33 or PBS vehicle was given I.P. to CVB3-infected mice every other day from day 1 to 9 post infection (pi). Heart function was examined by in-vivo catheterization at day 10 pi – the time when mice have previously been determined to develop fulminant myocarditis.  Tissue was then harvested for molecular and histological analysis.

Results: Mice that received IL-33 had three times more myocardial inflammatory cell infiltration than PBS controls, which was prominent along the pericardium. Levels of IL-33 were significantly increased in the hearts of mice receiving rIL-33, and levels of sST2 were increased in sera.  Viral replication in the heart and pancreas remained unaltered by rIL-33. In-vivo hemodynamic assessment suggests that rIL-33 administration impairs systolic function during acute myocarditis.  rIL-33 treated mice demonstrated an 11% decrease in systolic pressure, 40% decline in ventricular power, and 23% drop in contractility (dP/dT max) when compared to PBS treated controls.  rIL-33 treated mice also demonstrated a lack of beta adrenergic sensitivity as measured by isoproterenol challenge compared to controls.

Conclusion:  Activation of IL-33/ST2 signaling exacerbates myocarditis in two ways: 1) IL-33 increases the amount of inflammation entering the heart. 2) IL-33 impairs heart function by decreasing the heart’s ability to respond to B-adrenergic stimulants like adrenaline and isoproterenol – a common problem seen in human patients with heart failure.  The results of this study suggest that IL-33/ST2 signaling is not merely associated with changes in heart function, but is directly involved in the pathophysiology of heart disease development and progression.  Further study of this pathway leading to novel therapeutic targets may help treat or prevent cardiovascular diseases in the future.

3rd Place- Wen-Husuan Lin, PhD Candidate

Title: Successful respiratory immunization with dry powder live-attenuated measles vaccine

Measles remains an important cause of childhood mortality worldwide. Sustained high vaccination coverage is the key to preventing measles deaths.  Because measles vaccine is delivered by injection, hurdles to high coverage include the need for trained medical personnel, waste of vaccine in multi-dose vials and risks associated with needle use and disposal. Respiratory vaccine delivery could lower these barriers and facilitate sustained high coverage.  We developed a novel single unit dose, dry powder live-attenuated measles vaccine (MVDP) for respiratory delivery without reconstitution.  We tested the immunogenicity and protective efficacy in rhesus macaques of one dose of MVDP delivered either with a mask or intranasally with two dry powder inhalers, PuffHaler® and Solovent®.  MVDP induced robust measles virus (MeV)-specific humoral and T-cell responses, without adverse effects, which completely protected the macaques from infection with wild type MeV.  Respiratory delivery of MVDP was safe and effective and could aid in measles control.

2010 Poster Competition Winner Abstracts

1st Place- Applied Science and Overall Winner: Jesse Berman, PhD Candidate

Title: Health Benefits from Large Scale Ozone Reduction in the United States

Tropospheric ozone is one of six “criteria” air pollutants for which the U.S. Environmental Protection Agency (EPA) sets a health-based National Ambient Air Quality Standard (NAAQS).  The EPA monitors levels of ozone across the United States (US) through a network of air quality monitors.  Increased levels of ozone have been correlated with increased risk of adverse health effects, including premature mortality and related cardiopulmonary and respiratory morbidity.  In 2008, the United States Environmental Protection Agency (EPA) lowered the ozone NAAQS from 84 ppb to 75ppb, expressed as the maximum 8-hr average over a 24-hr period.  Based on current monitoring data, ozone levels in numerous locations across the U.S. exceed this standard.  The avoided potential adverse health impacts are quantified among the U.S. population associated with attaining the current and two alternative ozone NAAQS levels.  We estimate the avoided health impacts occurring after “rolling back” ozone values to just attain three alternate 8-hr ozone NAAQS: 75, 70, and 60 ppb (a range under current consideration for a revised ozone standard).  The two lower alternatives reflect the upper and lower-bound range of EPA Clean Air Scientific Advisory Committee recommended values.  The EPA Environmental Benefits Mapping and Analysis Program (BenMAP) is used to project the number of avoided cases of premature mortality and morbidity for an analysis year of 2007.  Using a suite of short-term ozone mortality studies (Bell et al. 2005 and Levy et al. 2005) the avoided incidences from current ozone-related all-cause premature mortality range from 290-410 at 75ppb, 580-820 at 70ppb, and 1,890-2,660 at 60ppb.  We also find that attaining the 75ppb standard result in prevention of 290 emergency room visits (respiratory) and 250 hospital admissions (respiratory), with a reduction of 550,250 acute respiratory symptoms and 237,100 lost school days.  Attainment of the 70 and 60 ppb 8-hr maximum levels yielded substantial additional health benefits, with about 1.1 and 3.5 million acute respiratory symptoms and 510 and 1,670 hospital admissions (respiratory) prevented at the 70 and 60ppb rollbacks, respectively.  Mapping of all scenario results display regional variation in health benefits, and reporting by metropolitan statistical areas (MSAs) show the greatest health benefits to be in the New York, Los Angeles, Philadelphia, and Riverside, California MSAs. 

2nd Place- Applied Science: Christen Fornadel, PhD Candidate

Title: Analysis of Anopheles arabiensis blood feeding behavior in southern Zambia during the two years following the introduction of insecticide treated bed nets

Anopheles arabiensis is the primary vector responsible for Plasmodium falciparum transmission in Macha, Zambia. Since insecticide treated bed nets (ITNs) have the potential to alter host feeding behavior, the extent of the vector’s zoophilic and exophagic tendencies was evaluated during the two rainy seasons following ITN introduction. Paired indoor/outdoor human landing catches (HLCs) and outdoor cattle-baited collections were used to assess potential changes in host preference. Results support the hypothesis that An. arabiensis in Macha remains highly anthropophilic despite high ITN use. Additionally, HLCs and Centers for Disease Control light traps were employed to determine if ITNs were having an effect on foraging behavior. Similar numbers of mosquitoes were caught in light traps hung next to treated and untreated bed nets, suggesting that ITNs have little effect on entering behavior. Although no repellant effect was observed, An. arabiensis in Macha appears to be relatively exophagic and has been caught biting outdoors both right after sunset and right before sunrise, potentially circumventing the protective effects of ITNs.

3rd Place- Applied Science: David Hanna, PhD Candidate

Title: Disparities in HIV-related mortality in persons with HIV infection by state, 34 US states, 2001-2006

Introduction:  Geographic disparities in HIV-related mortality highlight areas that may require more resources.  Published US HIV-related death rates by state have used general population denominators.  We used HIV-infected population denominators to control for prevalence differences among states, better reflecting the quality of care.

Methods:  We calculated HIV-related death rates per 1,000 HIV-infected person-years among persons age 15+ for 2001 through 2006 by state, age-adjusted to the 2000 US Standard Population.  Numerators were HIV-related deaths (defined by ICD-10 codes B20-B24) by state of residence at death from the National Vital Statistics System, which records the underlying cause of all US deaths.  Denominators were person-years based on yearly differences between cumulative HIV infection diagnoses and cumulative deaths among persons with those diagnoses, adjusted for reporting delays, by state of residence at diagnosis.  Denominator data came from the national HIV/AIDS Reporting System, which documents all persons diagnosed with HIV infection and their deaths, as reported to state health departments.  Negative binomial regression determined rate ratios (RRs) among states, adjusted for age, sex, race/ethnicity, and year.  Analysis was limited to 34 states with confidential name-based HIV reporting for at least four years.

Results:  Based on 2,437,274 HIV-infected person-years, the overall death rate due to HIV was 22.8/1,000 person-years (95% confidence interval [CI], 22.5-23.2).  Rates by state ranged from 10.5 (95% CI 8.8-12.3) to 35.2 (95% CI 31.8-38.7), showing significant heterogeneity across states even after adjusting for race/ethnicity (p<0.0001).  Rates increased by age (RR 1.36 per decade, 95% CI 1.35-1.38) and decreased by calendar year (RR 0.91, 95% CI 0.90-0.91).  States with the 11 highest rates were all in the southern region. 

Conclusions:  Our findings suggest that, among US states, the need for more resources to prevent HIV-related mortality is concentrated disproportionately in the South.  Policymakers should consider state or regional differences within a country when analyzing death rates.

1st Place- Basic/Lab Science: Jose Ramirez, PhD Candidate

Title: The Toll pathway is a conserved immune defense active against different dengue serotypes and present in multiple Aedes aegypti strains

The dengue virus has become one of the most important arboviral pathogens given the recent increase in incidence in the tropics and subtropics. It is transmitted among humans, primarily by the mosquito Aedes aegypti. Dengue transmission and disease dynamics are exacerbated by the existence of four closely related dengue serotypes. Mosquito vectors are able to limit infection with certain pathogens by mounting a range of immune responses. Although great advances have been made in understanding the mosquito responses to other pathogens such as Plasmodium, little is known about the mosquito antiviral immune responses.

Our previous studies have demonstrated the implication of the Toll Pathway as part of the anti-dengue defense repertoire at 7days post-infection. In this study we have assessed the anti-dengue effectiveness of this pathway at the early stage of infection and against different dengue virus serotypes and in field-derived mosquitoes. We observed that the Toll pathway is active at the early stages of infection (72h post-infection), at the time when new virions are released from the midgut for widespread dissemination. Furthermore, this immune defense is effective against other dengue virus serotypes and present in different strains of field-derived Aedes aegypti mosquitoes. This work adds important information to our understanding of mosquito-dengue virus interactions at the early stages of infection and key factors that modulate dengue transmission. The implication of the mosquito’s innate immune system in the defense against infection was investigated through reverse genetic RNAi methodology and viral plaque assays.

2nd Place- Basic/Lab Science: Shuzhen Sim

Title: Dengue virus inhibits immune signaling in Aedes aegypti cells

The ability of many viruses to manipulate the host antiviral immune response often results in complex host-pathogen interactions. In order to study the interaction of dengue virus (DENV) with the Aedes aegypti immune response, we have characterized the DENV infection-responsive transcriptome of the immune-competent A. aegypti cell line Aag2. As in mosquitoes, DENV infection transcriptionally activated the cell line Toll pathway and a variety of cellular physiological systems. Most notably, however, DENV infection down-regulated the expression levels of numerous immune signaling molecules and antimicrobial peptides (AMPs). Functional assays showed that transcriptional induction of AMPs from the Toll and IMD pathways in response to bacterial challenge is impaired in DENV-infected cells. In addition, Escherichia coli, a Gram-negative bacterial species, grew better when co-cultured with DENV-infected cells than with uninfected cells, suggesting a decreased production of AMPs from the IMD pathway in virus-infected cells. Pre-stimulation of the cell line with Gram-positive bacteria prior to DENV infection had no effect on DENV titers, while pre-stimulation with Gram-negative bacteria resulted in an increase in DENV titers. These results indicate that DENV is capable of actively suppressing immune responses in the cells it infects, a phenomenon that may have important consequences for virus transmission and insect physiology.

3rd Place- Basic/Lab Science: Talibah Metcalf, PhD Candidate

Title: Characteristics of trafficking and long-term maintenance of B-cells in the central nervous system in response to Sindbis virus infection

Alphaviruses are mosquito-borne message-sense RNA viruses that can cause encephalitis in a wide range of vertebrates including humans. Previous studies with Sindbis virus (SINV), the prototype alphavirus, have shown that infectious virus is cleared within 7-9 days, but that viral RNA persists. IFN-gamma plays a role in noncytolytic clearance of virus from neurons and anti-viral antibodies are important for both viral clearance and suppression of viral reactivation. After recovery, SINV-specific antibody secreting cells are present in the central nervous system (CNS) for the life of the animal. However, little is known about the changing functional characteristics of B-cells and important determinants of B-cell trafficking and long-term maintenance in the CNS.  To characterize the B-cell subset populations in the periphery and CNS tissue, as well as to understand the role of chemokines, C57BL/6 mice were infected intracerebrally with SINV and tissue was assessed at various times after infection by flow cytometry and qRT-PCR.

Plasmablasts and memory B-cells (CD19+CD38+CD138-IgM-IgD-) were 70% of the B-cell population for at least 6 months, while plasma cells (CD19+/-CD38-CD138+) were less than 5% of the population. Staining for intracellular and surface IgG at day 60 identified 40% of the B cells as plasmablasts and 50% as memory cells.  A small population of CD19+CD38-CD138- cells, characteristic of germinal center B-cells, was detected and this was confirmed by staining for the germinal center marker GL7. Levels of CXCL9/CXCL10/CCL3/CCL5 (leukocyte trafficking), CCL19/CXCL13 (follicle formation), and BAFF (B-cell survival) mRNAs peaked between days 5-7 after infection, followed by a gradual decreased and return close to baseline by 6 months, except for BAFF that was maintained at a low level. The expression of CXCR3 (receptor for CXCL9/10), CCR5 (receptor for CCL3/5), CCR7 (receptor for CCL19), and BAFF receptor was detected on CNS B-cells. 

These results show that plasmablasts and memory B-cells are present for months after infectious virus has been cleared and could play a role in the long-term suppression of SINV replication.  The detection of germinal center B-cells along with the early upregulation of chemokines involved in follicle formation suggest the formation of germinal centers in the brain in response to SINV infection.  The low levels of BAFF mRNA coincide with the low number of B-cells present after 2 months suggesting the brain provides a microenvironment for differentiation and survival of these cells.

 

2009 Poster Competition Winner Abstracts

Introduction:  Geographic disparities in HIV-related mortality highlight areas that may require more resources.  Published US HIV-related death rates by state have used general population denominators.  We used HIV-infected population denominators to control for prevalence differences among states, better reflecting the quality of care.

Methods:  We calculated HIV-related death rates per 1,000 HIV-infected person-years among persons age 15+ for 2001 through 2006 by state, age-adjusted to the 2000 US Standard Population.  Numerators were HIV-related deaths (defined by ICD-10 codes B20-B24) by state of residence at death from the National Vital Statistics System, which records the underlying cause of all US deaths.  Denominators were person-years based on yearly differences between cumulative HIV infection diagnoses and cumulative deaths among persons with those diagnoses, adjusted for reporting delays, by state of residence at diagnosis.  Denominator data came from the national HIV/AIDS Reporting System, which documents all persons diagnosed with HIV infection and their deaths, as reported to state health departments.  Negative binomial regression determined rate ratios (RRs) among states, adjusted for age, sex, race/ethnicity, and year.  Analysis was limited to 34 states with confidential name-based HIV reporting for at least four years.

Results:  Based on 2,437,274 HIV-infected person-years, the overall death rate due to HIV was 22.8/1,000 person-years (95% confidence interval [CI], 22.5-23.2).  Rates by state ranged from 10.5 (95% CI 8.8-12.3) to 35.2 (95% CI 31.8-38.7), showing significant heterogeneity across states even after adjusting for race/ethnicity (p<0.0001).  Rates increased by age (RR 1.36 per decade, 95% CI 1.35-1.38) and decreased by calendar year (RR 0.91, 95% CI 0.90-0.91).  States with the 11 highest rates were all in the southern region. 

Conclusions:  Our findings suggest that, among US states, the need for more resources to prevent HIV-related mortality is concentrated disproportionately in the South.  Policymakers should consider state or regional differences within a country when analyzing death rates.

1st Place- Basic/Lab Science: Jose Ramirez, PhD Candidate

Title: The Toll pathway is a conserved immune defense active against different dengue serotypes and present in multiple Aedes aegypti strains

The dengue virus has become one of the most important arboviral pathogens given the recent increase in incidence in the tropics and subtropics. It is transmitted among humans, primarily by the mosquito Aedes aegypti. Dengue transmission and disease dynamics are exacerbated by the existence of four closely related dengue serotypes. Mosquito vectors are able to limit infection with certain pathogens by mounting a range of immune responses. Although great advances have been made in understanding the mosquito responses to other pathogens such as Plasmodium, little is known about the mosquito antiviral immune responses.

Our previous studies have demonstrated the implication of the Toll Pathway as part of the anti-dengue defense repertoire at 7days post-infection. In this study we have assessed the anti-dengue effectiveness of this pathway at the early stage of infection and against different dengue virus serotypes and in field-derived mosquitoes. We observed that the Toll pathway is active at the early stages of infection (72h post-infection), at the time when new virions are released from the midgut for widespread dissemination. Furthermore, this immune defense is effective against other dengue virus serotypes and present in different strains of field-derived Aedes aegypti mosquitoes. This work adds important information to our understanding of mosquito-dengue virus interactions at the early stages of infection and key factors that modulate dengue transmission. The implication of the mosquito’s innate immune system in the defense against infection was investigated through reverse genetic RNAi methodology and viral plaque assays.

2nd Place- Basic/Lab Science: Shuzhen Sim

Title: Dengue virus inhibits immune signaling in Aedes aegypti cells

The ability of many viruses to manipulate the host antiviral immune response often results in complex host-pathogen interactions. In order to study the interaction of dengue virus (DENV) with the Aedes aegypti immune response, we have characterized the DENV infection-responsive transcriptome of the immune-competent A. aegypti cell line Aag2. As in mosquitoes, DENV infection transcriptionally activated the cell line Toll pathway and a variety of cellular physiological systems. Most notably, however, DENV infection down-regulated the expression levels of numerous immune signaling molecules and antimicrobial peptides (AMPs). Functional assays showed that transcriptional induction of AMPs from the Toll and IMD pathways in response to bacterial challenge is impaired in DENV-infected cells. In addition, Escherichia coli, a Gram-negative bacterial species, grew better when co-cultured with DENV-infected cells than with uninfected cells, suggesting a decreased production of AMPs from the IMD pathway in virus-infected cells. Pre-stimulation of the cell line with Gram-positive bacteria prior to DENV infection had no effect on DENV titers, while pre-stimulation with Gram-negative bacteria resulted in an increase in DENV titers. These results indicate that DENV is capable of actively suppressing immune responses in the cells it infects, a phenomenon that may have important consequences for virus transmission and insect physiology.

3rd Place- Basic/Lab Science: Talibah Metcalf, PhD Candidate

Title: Characteristics of trafficking and long-term maintenance of B-cells in the central nervous system in response to Sindbis virus infection

Alphaviruses are mosquito-borne message-sense RNA viruses that can cause encephalitis in a wide range of vertebrates including humans. Previous studies with Sindbis virus (SINV), the prototype alphavirus, have shown that infectious virus is cleared within 7-9 days, but that viral RNA persists. IFN-gamma plays a role in noncytolytic clearance of virus from neurons and anti-viral antibodies are important for both viral clearance and suppression of viral reactivation. After recovery, SINV-specific antibody secreting cells are present in the central nervous system (CNS) for the life of the animal. However, little is known about the changing functional characteristics of B-cells and important determinants of B-cell trafficking and long-term maintenance in the CNS.  To characterize the B-cell subset populations in the periphery and CNS tissue, as well as to understand the role of chemokines, C57BL/6 mice were infected intracerebrally with SINV and tissue was assessed at various times after infection by flow cytometry and qRT-PCR.

Plasmablasts and memory B-cells (CD19+CD38+CD138-IgM-IgD-) were 70% of the B-cell population for at least 6 months, while plasma cells (CD19+/-CD38-CD138+) were less than 5% of the population. Staining for intracellular and surface IgG at day 60 identified 40% of the B cells as plasmablasts and 50% as memory cells.  A small population of CD19+CD38-CD138- cells, characteristic of germinal center B-cells, was detected and this was confirmed by staining for the germinal center marker GL7. Levels of CXCL9/CXCL10/CCL3/CCL5 (leukocyte trafficking), CCL19/CXCL13 (follicle formation), and BAFF (B-cell survival) mRNAs peaked between days 5-7 after infection, followed by a gradual decreased and return close to baseline by 6 months, except for BAFF that was maintained at a low level. The expression of CXCR3 (receptor for CXCL9/10), CCR5 (receptor for CCL3/5), CCR7 (receptor for CCL19), and BAFF receptor was detected on CNS B-cells. 

These results show that plasmablasts and memory B-cells are present for months after infectious virus has been cleared and could play a role in the long-term suppression of SINV replication.  The detection of germinal center B-cells along with the early upregulation of chemokines involved in follicle formation suggest the formation of germinal centers in the brain in response to SINV infection.  The low levels of BAFF mRNA coincide with the low number of B-cells present after 2 months suggesting the brain provides a microenvironment for differentiation and survival of these cells.

 

2009 Poster Competition Winner Abstracts

1st Place-Applied Science and Overall Winner: Brandon Brown, PhD Candidate

Title: Peruvian FSWs: understanding HPV and barriers to vaccination

Objectives: To determine the level of awareness of human papillomavirus (HPV), and investigate the potential acceptability of HPV vaccine among female sex workers (FSWs) in Peru.

Methods: Behavioral and vaccine related knowledge data were collected from FSWs aged 18-29 in Lima, Peru. These questionnaires were administered individually by trained interviewers at Patrucco Clinic and surrounding sex venues using convenience sampling.

Results: The average age of the 319 women in our study was 24 years, and the mean age of first sex work is 20.51 years. Less than half (44%) of FSWs had heard of HPV and 47% correctly reported HPV as the cause of cervical cancer. 65% of women reported that condoms prevent HPV infection, while only 7% knew of a vaccine to prevent cervical cancer. Overall, clinic attendees were more knowledgeable about HPV than women approached at sex venues. Nearly 100% of participants would like to receive HPV vaccine, but many listed potential barriers to vaccination. Only eight women said they would not pay for an HPV vaccine, while the average amount women were willing to pay is 27.7 dollars (range 1.8-357 dollars). 99% of women reported being able to complete all 3 vaccine doses.

Conclusions: FSWs are a population at high risk of HPV infection and subsequent cervical cancer, thus they should have access to HPV vaccine. Due to low knowledge of HPV and cervical cancer, FSWs should be targeted for HPV education campaigns. Barriers to vaccination of FSWs can be overcome.

2nd Place-Applied Science: Miranda Jones, MHS Candidate

Title: Secondhand Tobacco Smoke Exposure in Motor Vehicles

Context: Increasing research has given rise to more smoke-free environments in an effort to protect non-smokers from the adverse health outcomes associated with secondhand tobacco smoke. However, many non-smokers still remain vulnerable to secondhand smoke exposure when traveling within a motor vehicle with a smoker. Due to the confined space within a motor vehicle, tobacco smoke concentrations may increase rapidly and intensify the hazards of secondhand smoke exposure.

Objective: To assess exposure to secondhand tobacco smoke in motor vehicles using passive airborne nicotine samplers.

Methods: Seventeen smokers and five non-smokers who commute to and from work in their own vehicle participated. Two passive airborne nicotine samplers were placed in each vehicle for a 24-hour period, one at the front passenger seat headrest and the other in the backseat behind the driver. At the end of the sampling period, airborne nicotine was analyzed by gas chromatography.

Results: Median (IQR) air nicotine concentrations in smokers vehicles were 9.6 g/m3 (5.3-25.5) compared to non-detectable concentrations in non-smokers vehicles. After adjustment for vehicle size, window opening, air conditioning, and sampling time, there was a 1.96-fold increase (95% CI 1.43, 2.67) in air nicotine concentrations per cigarette smoked.

Conclusion: Air nicotine concentrations in motor vehicles were much higher than air nicotine concentrations generally measured in public or private indoor places, and even higher than concentrations measured in restaurants and bars. These high levels of exposure to SHS support the need for education measures and legislation that regulate smoking in motor vehicles when passengers, especially children, are present.

3rd Place- Applied Science: Prabu Selvam, MHS Candidate

Title: Determining Potential Infectiousness using Cough Plates in Tuberculosis Endemic Settings in Peru

Background: This study aims to evaluate a novel cough aerosol capture technique that utilizes a selective solid culture medium and a direct patient cough on to a Petri dish containing a selective growth medium. Using a cough sample to isolate Mycobacterium tuberculosis may give a direct measure of infectivity that can guide control measures in endemic settings.

Methods: Suspected tuberculosis patients were asked to cough on a cough plate for direct culture. Each aerosol sample was accompanied by a sputum sample for comparison with MODS sputum liquid culture and acid-fast sputum smear microscopy. A total of 395 subjects were recruited from a shantytown community near Lima, Peru. Of all subjects, 45.6% (180/395) were MODS sputum culture positive.

Results: The cough plate returned a positive result for 14% (23/164, 95%CI: 9.1 20.3) of all MODS culture positive patients, while 31.0% (9/29, 95%CI: 15.3 50.8) of culture positives were cough plate positive among subjects with sputum smears indicating high bacterial load (BK=3). Specificity was 100% (204/204) when comparing cough plate to MODS. There were five subjects who were positive under MODS and cough plate but negative with sputum smear.

Conclusion: Cough Plate positivity perfectly predicts MODS positivity. Since higher bacterial load increases the chances of expelling M. tuberculosis in cough aerosols, the results of the cough plate confirm a generally understood relationship between high bacterial load and potential for infectiousness. Only a minority of patients were identified by the cough plate technique, and this outcome is in line with prior work regarding the identification of infectious patients

1st Place-Basic/Lab Science: Christopher Harvey, PhD Candidate

Title: Nrf2- A novel target to improve host antibacterial defenses in high risk populations

Rationale: Immunocompromised populations, including COPD patients, are at high risk for bacterial and viral infections that exacerbate preexisting disorders. While ninety percent of COPD is associated with cigarette smoking, smoke exposure itself has been associated with impaired phagocytosis in alveolar macrophages. Several studies have also indicated that chronic intake of corticosteroid drugs, which are commonly administered to treat the symptoms of COPD, leads to immunosuppression and enhances the risk of bacterial pneumonia. Recently, our laboratory has indicated that Nrf2 is the primary transcription factor that regulates innate antibacterial defenses, including antimicrobial peptides and the scavenger receptor MARCO. The present study was designed to investigate if Nrf2 activation improves innate immune antibacterial defenses using a smoke exposed mouse model and human COPD macrophages.

Methods: Wild type (Nrf2+/+) and Nrf2 deficient (Nrf2-/-) mice were exposed to cigarette smoke or filtered air for 1 day. Subsequently, mice were administered sulforaphane, a phytochemical activator of Nrf2, or vehicle via nebulizer followed by intranasal instillation of P. aeruginosa. After infection, BAL was analyzed for inflammation and bacterial colonization. Human macrophages were derived from COPD patients and treated with either vehicle or sulforaphane followed by inoculation with P. aeruginosa. Bacterial clearance was measured 4hr after addition of P. aeruginosa.

Results: Cigarette smoke impairs bacterial clearance in lungs of mice. Nrf2 deficiency further impairs bacterial clearance and killing following smoke exposure. Pharmacological activation of Nrf2 by sulforaphane restores the phagocytic activity of only Nrf2+/+ macrophages and significantly decreases bacterial colonization. Culture media obtained from sulforaphane treated Nrf2+/+ macrophages also showed significant bactericidal activity. Macrophages derived from COPD patients show impaired bacterial killing. However, pharmacological activation of Nrf2 restored bactericidal activity (3-fold increase in bacterial clearance). Conversely, P. aeruginosa continued to multiply in the media of vehicle treated human macrophages.

Conclusion: Modulation of innate immune activity through consumption of a phytochemical activator of Nrf2 may be a viable prophylactic/therapeutic means of preventing severe bacterial infections in immunocompromised individuals.

2nd Place-Basic/Lab Science: Talia Chalew, PhD Candidate

Title: Development of Assay to Assess Environmental Impacts of Engineered Nanoparticles on Chesapeake Bay Oysters

Over 500 consumer products are currently on the market that include and utilize engineered nanoparticles. Every day usage of these products is associated with the release of nanoparticles to the aquatic environment. As sessile filter feeding organisms, oysters are ecologically relevant indicator species for water contamination and economically important to the Chesapeake Bay region. However, little is known about the effects of engineered nanoparticles on these aquatic organisms, as methods for assessing the toxicological effects of engineered nanoparticle exposure are under development. Native Chesapeake Bay oysters have been devastated by Dermo (Perkinsus marinus) disease, which infect oysters through phagocytosis. In our study, titanium dioxide (TiO2) was utilized as a test particle due to high consumer usage and expected high abundance in the environment. Our experiments were focused on in vitro studies exploring the effects of nanoparticles on oyster hemocytes, which are the first line of oyster's immune responses against pathogens, including P. marinus. Our data show that waterborne engineered nanoparticles alter the dynamic of hemocyte phagocytosis, qhich might contribute to the decrease in Chesapeake Bay-native oyster populations. This research project impacts the health of the Chesapeake Bay oyster populations and public health, as oysters harvested from the Bay are consumed raw.

3rd Place-Basic/Lab Science: Allison Brown, PhD Candidate

Title: In utero exposure to maternal schistosomiasis modulates both acute and memory cellular and humoral immune responses of their offspring

Observational studies in humans indicate that in utero exposure to maternal helminth infection modulates immune responses to vaccines in their children, although the immunological mechanisms have not been identified. Helminth antigens cross the placenta and transplacental transfer of cytokines, antibodies or maternal lymphocytes may play a role in immune modulation. To investigate the mechanisms by which maternal helminth infection modulates immune responses to vaccines in their offspring, we developed a murine model of in utero exposure to maternal schistosomiasis. Balb/c dams were exposed to ~20 live Schistosoma mansoni cercariae and mated with Balb/c males 6 weeks after infection. Offspring of infected and uninfected dams received an alphavirus replicon expressing measles virus H protein (VCR-H) or a PBS control vaccine at 4 weeks of age, and were sacrificed at 2 or 6 weeks after vaccination. Using ELISPOT assays to measure splenocyte responses to bystander and vaccine-specific antigens, a dose response effect was observed between maternal egg burden and IL-4 and IFN- cytokine production at 2 and 6 weeks post-vaccination. Acute responses at 2 weeks post-vaccination were directly correlated with maternal egg burden. In contrast, memory responses at 6 weeks were inversely correlated with maternal egg burden, suggesting that in utero exposure results in short-term activation but long-term suppression of T cell responses after vaccination. CD4+ T cells were the primary producers of IL-4 by intracellular cytokine staining, and CD8+ T cells were the primary producers of IFN- . Increased egg burden and longer duration of infection in dams were associated with CD4+ T cell populations with regulatory T cell profiles (expressing CD25, Foxp3 or both) in their offspring, a potential mechanism of long-term immune suppression following in utero exposure to maternal schistosomiais. Among VCR-H vaccinated offspring, the IgG2a to IgG1 ratio increased with maternal egg exposure, consistent with enhanced Th1 skewing, but total vaccine-specific IgG titers decreased with increasing maternal egg exposure. These observations demonstrate that in utero exposure to maternal infection modulates both the acute and memory cellular and humoral immune responses of their offspring, and may decrease vaccine efficacy in offspring

2008 Poster Competition Winner Abstracts

1st Place-Basic/Lab Science Lindsey Garver

Project Title: Silencing of an immune pathway negative regulator renders mosquitoes resistant to the human malaria parasite

Project Summary:

Malaria is one of the mostly costly infectious diseases in the world both in terms of human life and economic loss. In areas of developed nations, malaria eradication has been made possible by control of the Anopheles mosquito that transmits Plasmodium, the malaria parasite. We and others hypothesize that manipulating the molecular immune response of the mosquito to render the insect unable to support infection would offer a novel way to control malaria. Immune responses mounted by the malaria vector Anopheles gambiae are largely regulated by the Toll and Imd pathways, which control the nuclear translocation of two NF-kappaB-like transcription factors, Rel1 and Rel2, respectively. Activation of Rel1 and Rel2 by these pathways is controlled by the negative regulators AgCactus and AgCaspar. Rel1- and Rel2-dependent transcription in A. gambiae has been shown to be particularly critical to the mosquito_s ability to manage infection with the rodent malaria parasite (Meister et al. 2005, Frolet et al. 2006). Using RNA interference to deplete the negative regulators, we found that Rel2 activation resulting from AgCaspar depletion rendered the mosquitoes resistant to the human malaria parasite Plasmodium falciparum at the pre-mature oocyst stage. Mosquitoes devoid of the Toll pathway regulator Cactus were, on average, 66% more resistant than control mosquitoes. High-density microarray-based, genome-wide expression analyses identified a plethora of genes that were regulated by the activation of the two Rel factors via AgCactu and AgCaspar depletion. The A. gambiae Toll pathway displayed a significantly more diverse role in mosquito biology than did the Imd pathway, which was more immunity-specific. Gene silencing of AgCactus induced 471 and repressed 117 genes, while AgCaspar silencing induced 61 and repressed 55 genes. Depletion of AgCactus and AgCaspar affected the expression of 31 and 17 immune genes, respectively, including anti-Plasmodium factors. The fitness cost of AgCaspar depletion, as measured by mosquito longevity, blood-feeding propensity and oviposition, was insignificant. These findings suggest that this broad-spectrum immune activation in A. gambiae offers an interesting approach to developing novel malaria control strategies

2nd Place-Basic/Lab Science: April Neal

Project Title: Effects of Long Term Lead Exposure on Pre- and Post-Synaptic Protein Markers

Project Summary:

Lead (Pb2+) exposure can result in cognitive deficits in humans and in animal models. The developing neuron is particularly sensitive to Pb2+, although the exact cause of Pb2+-mediated cognitive deficits is unknown. A large body of evidence indicates that the N-methyl-d-aspartate receptor (NMDAR) may mediate Pb2+ effects on synaptic plasticity and cognition. Other evidence suggests changes in pre-synaptic elements by Pb2+. Therefore, synaptic glutamatergic transmission may play a critical role in Pb2+-induced neurotoxicity. In this study we investigated the composition of synapses in developing neurons at 7 days in vitro (DIV7) using western blotting and immunocytochemistry. DIV7 hippocampal neurons were exposed to 0, 0.01, 0.1 and 1.0 uM Pb2+ for 5 days, at which point cells were harvested for protein analysis. Using western blots, we found that synaptophysin protein levels decreased in response to Pb2+, with significant changes occurring at 0.1 uM and 1.0 uM Pb2+. In contrast, the protein levels of MAP2 and NR2B remained the same. Analysis showed that the amount of NR1 and NR2A co-localized with synaptophysin decreased significantly at 0.1 and 1.0 mM Pb2+ while the amount of NR2B co-localized with synaptophysin did not change. Additionally, the area of PSD-95 puncta increased significantly at 0.01 uM, while the overall number of puncta per mm did not change significantly at any dose. Taken together, these data indicate that Pb2+ causes changes at both pre-synaptic active zones and post-synaptic spines. We have shown a specific decrease in the pre-synaptic protein synaptophysin which may represent a direct effect of Pb2+ on protein levels and not a change in pre-synaptic terminals since MAP2 protein levels and PSD-95 immunopostive spine density were unaffected by Pb2+. However, PSD-95 puncta area significantly increased at 10 nM Pb2+ exposure, possibly indicating an increase either in the total spine area or an increase in the levels of splitting synapses at very low levels of Pb2+ exposure. Reduced co-localization of synaptophysin with the NMDAR subunits NR1 and NR2A but not NR2B suggests that glutamatergic synapses in dendritic spines expressing NR2A-containing NMDAR are significantly decreased by Pb2+ exposure. Since the age-dependent switch of NR2B-containing synapses to NR2A-containing synapses is an important milestone of developing neurons, our results suggest that Pb2+ may interfere with processes affecting maturation of signaling pathways by NR2A-containing NMDAR. [Grant #ES06189 to TRG]

3rd Place- Basic/Lab Science: David Sintasath

Project Title: Identification of a Novel Simian T-lymphotropic virus (STLV) Lineage in Two Monkey Species from Cameroon: High STLV Diversity at the Hunter-Primate Interface

Project Summary:

The recent discovery of novel HTLV-3 and HTLV-4 viruses in persons hunting and butchering nonhuman primates (NHPs) in Cameroon demonstrates that the genetic diversity and natural history of primate T-lymphotropic viruses (PTLVs) are far from being understood. To better understand the origin, genetic relatedness, and epidemiology of these novel HTLVs we investigated the prevalence and diversity of STLV in NHPs hunted in the forests of Cameroon. DNA was extracted from dried blood spots from 170 NHPs representing 12 different simian and prosimian species. PCR analysis using generic tax primers detected an overall STLV prevalence of 7% (12/170) in four simian species. Analysis of conserved tax sequences revealed a high PTLV diversity, including STLV-1 (n=7) and STLV-3 (n=3). Samples from a Cercopithecus mona and C. nictitans each had highly divergent STLV-3-related sequences. Phylogenetic analysis of larger tax sequences from these twomonkeys inferred a novel lineage outside the diversity of PTLV-3 suggesting a long, independent evolution of these viruses. STLV-3 LTR sequences from three different monkey species were all distinct including those from Lophocebus albigena, an NHP not known to be infected with STLV. STLV-1LTR sequences obtained from two monkey species (n=5) all clustered in the HTLV-1 D and F subgroups supporting a primate origin for these clades. The discovery of a novel STLV lineage and several unique STLV-3s significantly expands the range of PTLV diversity. The propensity of STLV to transmit to humans highlights the need for more active surveillance at the primate-human interface for cross-species transmission of deltaretroviruses.

3rd Place- Basic/Lab Science: Allison Brown

Project Title: In utero exposure to maternal Schistosoma mansoni infection in mice modulates immune responses to vaccines in their offspring

Project Summary:

Observational studies in humans indicate that in utero exposure to maternal helminth infection modulates the immune responses to vaccines in children; however, the mechanisms responsible are not known. Helminth antigens have been shown to cross the placenta but transfer of cytokines, antibodies and maternal lymphocytes also may play a role. To investigate mechanisms by which maternal helminth infection modulates immune responses to vaccines in their offspring, we developed a murine model of in utero exposure to maternal schistosomiasis. Balb/c dams were exposed to live Schistosoma mansoni cercariae and mated at 6 weeks post-infection. Offspring of infected and uninfected dams received either an alphavirus replicon expressing measles virus (MV) H protein (VCR-H), adsorbed tetanus toxoid (TT) or a PBS control vaccine at 4 weeks of age and were sacrificed 2 weeks later. Splenocyte production of IFN- and IL-4 was measured by ELISPOT in response to soluble adult worm antigen (SWAP), a T cell mitogen (ConA) and vaccine-specific antigens (MV H peptides and TT). VCR-H vaccinated offspring of infected dams displayed increased IFN- and IL-4 production upon stimulation with SWAP, mitogen and measles virus H peptides compared with offspring of uninfected dams (P = 0.03). Furthermore, there was a direct relationship between maternal egg burden and offspring cytokine production. VCR-H vaccinated offspring of dams with high hepatic S. mansoni egg counts produced significantly more IFN- and IL-4 than offspring born to dams with a lower egg burden (P = 0.05). Evidence of a dose response effect also was observed among the TT vaccinated offspring, with high maternal egg burden resulting in higher IFN- and IL-4 production upon SWAP, mitogen and TT stimulation (P = 0.06). A separate study aimed to determine whether host immune responses to repeated schistosomal infection differed from those after single exposure. Balb/c females were either singularly exposed to 30 live cercariae or exposed three times 3 weeks apart to 10 live cercariae. Mice repeatedly exposed to schistosomes experienced significantly increased production of IFN- in response to both ConA and SWAP (0.02 and 0.03, respectively) and increased IL-4 in response to ConA (0.05). Thus, both maternal schistosomiasis and repeated schistosome exposure result in increased IFN- and IL-4 production in response to schistosomal and non-schistosomal antigens. These studies demonstrate that prior immune sensitization to schistosome antigens enhances immune activation and may contribute to a variety of unforeseen consequences, including increased susceptibility to HIV transmission.

1st Place- Applied Science: Stephen Sozio

Project Title: Statins Do Not Increase Stroke Risk in Patients Initiating Dialysis: The Choices for Healthy Outcomes in Caring for End Stage Renal Disease (CHOICE) Study

Project Summary:

Introduction: Kidney disease has reached epidemic proportions with a predicted prevalence in 2030 of more than two million patients with end-stage renal disease. The 5-year survival of these patients is less than 50%, with stroke being the third leading cause of death. Contrary to the general population, there was an unexpected higher rate of stroke among those treated with HMG-CoA reductase inhibitors (statins) than placebo among prevalent diabetic hemodialysis patients in a prior randomized trial. It is not known if this was a type I error or a true association.

Methods: We investigated the association of statin use at baseline and cerebrovascular events (CVE) among a national, incident dialysis cohort of 1,041 patients enrolled from 10/95 to 7/98 in the CHOICE study. Incident CVE were defined as both non-fatal (hospitalized stroke, carotid endarterectomy) and fatal (stroke death) events after dialysis initiation. Participants were censored for transplant, non-stroke death, or 12/31/04. With Cox proportional hazards regression analysis, we assessed the independent risk of CVE associated with statin use after adjustment in separate models for a propensity to use statins score and for age, race, sex, history of CVE, smoking status, diabetes, hypertension, albumin, and cholesterol.

Results: Mean age was 58 years with 54% male, 67% White, 74% on hemodialysis, and 16% taking statins. A total of 164 patients experienced CVE; incidence rate was 5.2/100 person-years (95% confidence interval (CI)[3.3-7.8]) for those taking statins and 4.9/100 person-years (95%CI[4.1-5.7]) for non-statin users. Statin use was not associated with increased hazard of CVE in univariate (HR 1.07, 95%CI[0.72-1.60]), propensity-adjusted (HR 0.96, 95%CI[0.62-1.48]), or traditional multivariate analyses (HR 0.91, 95%CI[0.57-1.46]).

Conclusions: We conclude that statin use among incident dialysis patients neither increases nor decreases the risk of CVE. Further studies are needed to understand the pathophysiology and prevention of stroke in patients with ESRD.

2nd Place- Applied Science: Bruce Swihart

Project Title: The Lasagna Plot: A saucy new alternative to the Spaghetti Plot

Project Summary:

In public health, data are often collected at the subject level longitudinally. The gold standard for graphically displaying and exploring such data is the spaghetti plot, which involves plotting a subject's outcome measures (vertical axis) versus time (horizontal axis) and connecting the dots. Although useful for fewer subjects, trends and patterns tend to become obscured for large numbers of subjects. This is because trajectories can overlap in a spaghetti plot, for the magnitude of the outcome measure is the vertical dimension. Enter the lasagna plot, which uses color or shading to depict the magnitude of the outcome measurement and fixes the vertical dimension per subject. Thus each subject forms a "layer" in the lasagna plot. Two advantages of the lasagna plot over the spaghetti plot are 1) group level and individual level information are preserved regardless of the number of subjects or time points (no "overplotting"); 2) dynamic sorting of data to better ascertain group level behavior over time is possible

3rd Place- Applied Science: Stephanie Richard

Project Title: The 1918 Influenza Pandemic Experience in Japan: Age and Geographic Mortality Patterns

Project Summary:

A better understanding of past influenza pandemics is essential to prepare for future pandemics. Based on excess mortality models applied to historical vital statistics, we quantify the age and geographic mortality patterns of the 1918 pandemic in Japan, and compare with those in the US and the UK. During the 1918-20 pandemic period, all three countries experienced unusually high mortality in young adults. However, in contrast to the US and UK, Japanese elderly were not entirely spared and excess mortality in Japan was balanced between two seasons, 1918-19 and 1919-20. Surprisingly, Okinawa and prefectures in the densely populated region around Tokyo, partially escaped the first season, only to be more severely hit the following season. These geographical differences were not related to differences in population demographics or density. Our study and others suggest that influenza pandemic mortality patterns can vary substantially between countries
and regions, for reasons yet unclear.

2007 POSTER COMPETITION WINNER ABSTRACTS

Overall winner 1st Place- Applied Research: Sheng Luo

Title: Analysis of Smoking Cessation Patterns Using a Stochastic Mixed Effects Model with a Latent Cured State

Summary:

Background: Smoking is the leading preventable cause of death in the U.S. In the U.S. alone, 44.5 million adults, or 20.9% of the adult population were smokers in 2004; 440,000 annual premature deaths are attributable to smoking. Smoking is a major cause of a large number of diseases, e.g. cancers of the lung, larynx, and pharynx, etc. The slow reduction of adult smoking prevalence is partly due to high rates of relapse following quit attempts among smokers. A major problem when studying addiction behavior is that participants typically make several quit attempts before they successfully quit. Thus, for efficient development, targeting and evaluation of interventions, it is necessary to distinguish transient quitting (temporarily smoking-free but relapse later) from permanent quitting (lifelong smoking-free) and identify the risk factors associated with permanent quitting.

Objective: To identify and quantify baseline factors associated with success of permanent quitting and describe the full stochastic nature of the smoking addiction pattern using the Alpha-Tocopherol, Beta-Carotene (ATBC) Lung Cancer Prevention study data set.

Methods: The ATBC study is a large (29,133 participants) longitudinal cohort study and it contains unique information about smoking and health status of each participant during every 4-month interval throughout the follow-up period. We used the ATBC data set to model smoking cessation patterns using the proposed discrete-time stochastic mixed-effect model with three states: smoking, transient quitting and permanent quitting (absorbent state). Random participant specific transition probabilities among these states were used to account for participant-to-participant heterogeneity. Another important innovation in our research was to design computationally practical methods for dealing with the size of the data set and complexity of the models. This was achieved by integrating over the Beta distribution of random effects and obtaining the marginal likelihood as an explicit function of the model parameters. We thus avoided complicated model fitting techniques, e.g. numerical integration or Markov Chain Monte Carlo (MCMC). This provided large computational advantages over the more popular model using logistic multivariate normal random effects.

Results: Baseline age was positively associated with probability of making quit attempts (p<0.001). However, years of smoking, cigarette and alcohol consumption had inverse association with probability of making quit attempt (p<0.001). If the quit attempt was made, more cigarette consumption per day was associated with lower probability of relapsing (p=0.003), while more alcohol consumption per day was associated with higher probability of relapsing (p=0.004). Moreover, 5.1 years in age increased the odds of permanent quitting by 10.4% (95% CI: -0.40%~22.4%; p=0.06). Individuals with psychological symptoms were significantly less likely to be successful permanent quitters (p=0.03).

Conclusion: An important, previously unknown, but often debated, finding was that baseline risk factors have different effects on different transition probabilities. We provided mathematical quantification of the participant-to-participant variation in transition probabilities. Our modeling strategy enriched the statistical arsenal of cure modeling and provided new and valuable scientific insight into the smoking addiction behavior.

2nd Place- Applied Research: Honghong Zhu

Title: A Validation Study on Smoking Questionnaire in the Shanghai Women's Health Study

Summary:

In order to determine the potential exposure levels of secondhand smoke (SHS) at a population level and validate the self-reported smoking questionnaire in the Shanghai Women's Health Study, SWHS, we designed a cross-sectional validation study of urinary cotinine at baseline. A total of 571 urine samples were randomly selected by strata of smoking levels of neither active smoking nor SHS exposure (never SHS), former smokers, ever only exposure to SHS (only SHS), and current smokers. The geometric means (95% confidence intervals) for urinary cotinine were 2.8 (2.2-3.5), 3.4 (2.6-4.4), 5.2 (4.7-5.8) and 933.2 (551.4-1579.4) in ng/ml urine among women who reported never SHS, former smokers, only SHS, and current smokers, respectively. All women, including never SHS, had cotinine detectable in their urine samples. In the linear regression analysis, all the self-reported smoking measures at baseline were significantly correlated with urinary cotinine after adjusting for creatinine and other covariates. Urinary cotinine significantly increased by 0.370 ng/ml urine per one additional cigarette smoked per day by women and by 0.035 ng/ml urine per one additional cigarette smoked per day by their husbands. Spearman correlation coefficient, rs, with creatinine-adjusted urinary cotinine was 0.94 (p< 10-5) for cigarettes smoked per day by current-smoking women at baseline with a great variation of cotinine levels across individuals and 0.51 (p< 10-5) for cigarettes smoked per day by their husbands. The weighted Kappa coefficient was 0.95 (p< 10-5), indicating almost perfect agreement between self-reported smoking status and the urinary cotinine-indicated smoking status. Sensitivity for self-reported current smokers was 88% and specificity was 100%, when using the urinary cotinine-indicated smoking status as a gold standard. In conclusion, the smoking questionnaire of both active smoking and SHS in the SWHS is valid. However, the validity decreases slightly in quantitative measures of smoking due to the large variation of cotinine across individuals. The universal presence of cotinine in the urine samples suggests SHS is a severe public health issue in China.

3rd Place- Applied Research: Valerie Harder

Title: Applying alternative propensity score techniques to test whether marijuana problems cause depression

Summary:

Increased marijuana use among adolescents and reports linking marijuana use to other psychiatric disorders has prompted research on the relationship between adolescent marijuana use and later depression. Using propensity score (PS) adjustment techniques we test the potential causal link between adolescent marijuana problems (abuse or dependence) and young adult depression (past-year major depression diagnosis). A cohort of 2,311 first-graders was interviewed over a 15-year period with 75% retention. We used both parametric and non-parametric PS estimation techniques and five alternative applications of the PS, including matching, subclassification, and weighting. The PS adjusted the final logistic regression of depression on marijuana problems by balancing all observed confounding covariates. Unadjusted, 24% of individuals with marijuana problems reported depression whereas only 13% of individuals without marijuana problems reported depression. The PS-adjusted analyses all resulted in increased odds of depression among those with marijuana problems [Odds Ratio range 1.12 (p>0.05) 1.88 (p<0.001)]. The variation in the magnitude of the effect and statistical significance does not directly suggest one of the PS techniques to be superior. We use statistical simulations and comparisons of the baseline covariate balance to determine if one PS method is most effective. This work suggests both methodological and substantive conclusions: non-parametric estimation of the PS may be an improvement over parametric estimation for these data, and adolescents with marijuana problems are at increased odds for young adult major depression, but the causal link is modest.

1st Place- Basic/Lab Science: Lindsey Garver

Title: The immunoglobulin superfamily in Anopheles gambiae: potential immune molecules in the malaria vector

Summary:

Although falciparum malaria is one of the most devastating infectious diseases in the world, proper control of the parasite and its vector, the Anopheles gambiae mosquito, remain elusive. Because the mosquito vector is required for transmission and because vector control can be cost-effective and is unaffected by compliance of individuals, we are focused on finding a way to control malaria though molecular manipulation of the mosquito. The mosquito's immune system is active against the malaria parasite yet determination of the molecules and mechanisms involved is still in its infancy. Because immunoglobulin superfamily members are among the most important and best characterized molecules of the immune system and this family has not been well-studied in the context of insect immunity, we initiated a screen of mosquito proteins containing immunoglobulin domains to identify candidate immune molecules. First, a bioinformatics-based analysis was used to define the IgSF in Anopheles gambiae and select and test candidates for implication in immune functions. This screen identified 145 genes that have at least one immunoglobulin domain. From here, a gene expression-based analysis was performed in order to determine the infection responsiveness of individual exons representing each of the 145 IgSF genes. Expression profiles of adult female mosquitoes and mosquito cell lines challenged with Plasmodium parasites, Gram negative bacteria, Gram positive bacteria and fungi show that 237 exons from 84 genes are significantly regulated in response to at least one challenge, many responding to multiple challenges. We think that some of this regulation is attributable to immune defense. Data from both the computational and microarray screens were used to choose six genes as candidates for further functional analyses to establish possible immune relevance. Candidates were named Infection Responsive with Immunoglobulin Domain 1-6 (IRID1-6), and chosen for testing based on domain composition suggestive of immune relevance and significant regulation of at least two exons upon challenge. Each of the six IRID genes were silenced in adult female mosquitoes using RNAi and subsequently challenged with Gram positive bacteria, Gram negative bacteria or Plasmodium. Survival rates and oocyst loads from these assays suggest several of these candidates are involved in defense against these pathogens. One candidate, IRID3, seems to have a drastic effect on a mosquito's ability to survive after bacterial challenge and another, IRID6, has a modulatory effect on Plasmodium falciparum infection in the mosquito. From here, we can begin our characterization of IRID3 and IRID6 which may not only represent a novel class of innate immune molecules. IRID6 is of particular interest as a potential target for malaria control at the vector level.

2nd Place Basic/Lab Science: Judith Easterbrook

Title: Regulatory T Cells Mediate Seoul Virus Persistence and Pathology in Norway Rats

Summary:

Hantaviruses cause one of two diseases in humans, hantavirus pulmonary syndrome (HPS) or hemorrhagic fever with renal syndrome (HFRS). Human pathology is hypothesized to be caused by sustained, elevated levels of proinflammatory cytokines. In rodents, hantaviruses are transmitted horizontally and cause persistent infection in the absence of disease. The mechanisms mediating hantavirus persistence in rodents are unknown. Regulatory T cells contribute to persistence of several pathogens and act locally at sites of pathogen replication by suppressing proinflammatory responses. Following inoculation with Seoul virus, regulatory T cells (CD4+CD25+FoxP3+) are elevated in the lungs during the persistent phase of infection (i.e. at Day 30 p.i.). Additionally, expression of foxp3, a transcription factor that is unique to regulatory T cells, and TGF-, a cytokine produced by regulatory T cells, is elevated in the lungs of male Norway rats 30 days post-inoculation (p.i.), but remains unchanged in the spleen during infection. To test the hypothesis that regulatory T cells affect persistence of Seoul virus, male Norway rats were administered anti-CD25 mAb, to deplete regulatory T cells, or saline and were inoculated with Seoul virus or vehicle. Following depletion of regulatory T cells, Seoul virus RNA copies in the lungs and proportion of rats shedding virus in saliva are reduced during infection. Additionally, depletion of regulatory T cells significantly reduces pathology, including development of hemorrhage and edema, in the lungs during Seoul virus infection. Taken together, these data suggest that regulatory T cell responses are elevated during infection and may contribute to Seoul virus persistence and pathology in male Norway rats.

3rd Place Basic/Lab Science: JInchun Yan

Title: Increased androgenic sensitivity during aging contributes to the prostate proliferative potential

Summary:

Benign prostate hyperplasia (BPH) is a prevalent condition in aging men. Spontaneous epithelial cell hyperplasia in the dorsal and lateral lobes of old Brown Norway rats is analogous to BPH in humans. Therefore, the Brown Norway (B-N) rat represents an excellent model to investigate the mechanisms that regulate cell proliferation and prostate hyperplasia. The majority of cells in the adult prostate are quiescent in the G0 phase and in order for hyperplasia to occur, cells must escape from cell cycle arrest and enter S phase through G1/S restriction. In the androgen withdrawn-replenished Brown Norway rats, proliferation rate quantified by BrdU labeling index of all three lobes in response to androgens is time and dose dependent, and peak at day 3. Under the similar serum testosterone levels monitored by radioimmunoassay, aging dorsal and lateral prostates have higher proliferation rate than the young animals, while there is no age dependent difference in proliferation rate of ventral lobes. Immunoblots demonstrated the abundance of cyclinD1, cdk6, cyclin E, cdk2 was significantly upregulated, and P27Kip1 abundance was significantly downregulated, affected by androgens. Interestingly, aging dorsal and lateral prostates have higher cyclin D1 and cyclin E abundance than the young ones, no matter the intact control animals, or the 3days androgen replenished young and aging animals under the similar serum testosterone levels. Androgens can also affect Rb phosphorylation, shown by immunoprecipitation and immunoblots. Immunostaining demonstrated changing patterns of cdk4 subcelluar localization and probability of cyclinD1 nuclei localization corresponded to the time frame of cell proliferation affected by androgens. These data suggested increased androgenic sensitivity and its effect on the key cell cycle regulators (especially those related to G1/S transitions) may be one of the multiple mechanisms leading to BPH, which develops during aging while the serum testosterone levels decrease.

2006 POSTER COMPETITION WINNER ABSTRACTS

OVERALL- Xiaoyan Song: Association of Serum Ferritin and Mortality in Incident Hemodialysis Patients

Summary:

Background: Each year, about 300,000 patients in U.S. receive hemodialysis (HD) to treat end stage renal disease. Given that almost every HD patient suffers from anemia and thus requires recombinant human erythropoietin (EPO) treatment, intravenous (IV) iron therapy has become one of the most important adjunctive treatments in anemic HD patients. Although IV iron is effective in correcting anemia, excessive iron in human body increases patient's risk of developing infections and cardiovascular diseases. Epidemiological studies addressing iron and mortality in HD patients provided controversial evidences, partially because these studies only followed patients for less than 2 years which were insufficient to assess the causal effect of iron on mortality.

Objective: To examine the relationship between serum ferritin (SF), a marker of body iron storage, and all-cause mortality in incident HD patients.

Method: A prospective longitudinal cohort study. Eligible patients were incident HD patients who were enrolled in the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study, an ongoing prospective study that had followed 1,041 incident dialysis patients recruited from 81 clinics nationwide since 1995, and had baseline SF values that were measured within 3 months of dialysis onset. Baseline patient characteristics (age, gender, race, smoking, employment and marital status) and co-morbidity were collected through a self-administered questionnaire. Clinical laboratory values including SF were obtained from an electronic database. Death was prospectively identified from medical records, national Death Certificate Index database, and U.S. Renal Disease System. Statistical analyses included descriptive analysis to examine associations between SF (grouped into <100 mg/dL, 100~500 mg/dL, 500~800 mg/dL, and >800 mg/dL for the ease of clinical interpretation), death and covariates. Unadjusted and adjusted Cox regression model was used to determine the independent effect of SF on mortality. Laboratory values including inflammatory marker C-reactive protein (CRP) were adjusted as time-dependent covariates. To further illustrate a potential causal effect of iron on mortality, we analyzed a group of patients who survived for at least 6 months from dialysis onset and excluded SF values that were measured within 6 months before the events (death or censoring) occurred.

Results: Of 767 HD patients enrolled in the CHOICE study, 687 (89.6%) had baseline SF available and 614 (80.1%) survived for at least 6 months after dialysis onset. Patients in the four SF groups were similar in baseline age, race, smoking, marital and employment status, and education levels. Baseline SF was positively associated with CRP (p=0.04), but negatively associated with albumin (p<0.001). No statistical association was found between baseline SF and mortality in the analysis using either whole- or sub- group data. Cox regression model using whole-cohort data found no association between follow-up SF and mortality. Comparing to the reference group 100~500 mg/dL, Hazard Ratio (HR) was 0.74 (95% Confidence Interval (CI): 0.45~1.23), 1.02 (95% CI: 0.75~1.39), and 1.16 (95%CI: 0.93~1.45) for SF<100, 500~800, and >800 mg/dL groups, respectively. Cox regression using sub-cohort data and excluding SF measured in the last 6 months before events occurred revealed that SF <100 mg/dL was associated with elevated mortality (HR: 1.26, 95%CI: 1.01~1.57). The association remained statistically significant after adjusting for CRP and albumin.

Conclusion: We found that low, rather than high, SF was associated with increased mortality. Our results suggested a reverse causal effect when using SF as a marker of body iron to assess its relationship with mortality in HD patients. Further study was warranted to confirm this finding.

Laboratory Research

1st Place- Caren Chancey: Combination of antibodies to CD18 and ICAM-1 reduces transmission of cell-associated HIV-1

Summary:

Background: A better understanding of the interactions between HIV-1 positive cells and the cervical epithelium is essential for development of microbicides to prevent sexual transmission of HIV-1 to women. Our lab has previously demonstrated that cell-associated transmission of HIV-1 by monocytes is the most efficient route of transmission across a model cervical epithelial monolayer and in a hu-PBL-SCID model of vaginal HIV-1 transmission. In addition, antibody to ICAM-1 has been shown to block transmission of cell-associated HIV-1 in both of these models. Use of lactobacilli to produce antibody-like single-chain Fvs (scFv) offers many advantages over traditional microbicides, but the available concentration of antibody is limited by the amount of scFv that can be secreted in vivo. In order to determine whether a significant reduction in the amount of antibody required to block HIV-1 transmission could be achieved, we evaluated the blocking capabilities of antibodies to CD18, the -chain of the ICAM-1 ligands LFA-1 and Mac-1, both separately and in combination with anti-ICAM-1.

Methods: Peripheral blood mononuclear cells (PBMC) infected with HIV-1 BaL were added to the apical side of confluent monolayers of HT-3 cervical epithelial cells grown on permeable transwell supports. After 24 hours, PBMC in the basal compartment were counted, and HIV transmission was measured by p24 ELISA on the basal supernatant. Data were analyzed using one-way ANOVA with Bonferroni correction by the STATA statistical package.

Results: Two different anti-CD18 antibodies, H52 and 7E4, were able to reduce transmission of cell-associated HIV-1 by 90.1% and 67.6%, respectively. Anti-CD18 and anti-ICAM-1 used in 50:50 combination at a total concentration of 5 ug/ml reduced migration of PBMC from HIV-1 infected cultures significantly better (p<0.05) than 20 ug/ml total of either antibody alone.

Conclusions: These findings indicate that a combination of antibodies to the adhesion receptor pair ICAM-1 and CD18 offers better protection against cell-associated HIV-1 transmission than either antibody alone, and that this combination can protect at a concentration which is feasible for use in a lactobacillus-based microbicide delivery system.


2nd- Place- John Pisciotta: Hemozoin Formation and Detection in P. falciparum

Summary:
The intraerythrocytic malaria parasite forms intracellular heme crystals, called hemozoin, as a means of detoxifying free heme released through hemoglobin catabolism. This process is targeted by the quinoline antimalarials. The intracellular mechanism of heme crystallization initiation has not been fully substantiated; however, histidine rich proteins, polar lipid and/or neutral lipids have all been purported to play a role. The current study employs the lipid fixative malachite green to observe neutral lipid nanospheres enveloping nascent hemozoin within P. falciparum digestive vacuoles (DV). Mass spectrometry lipidomics identifies significant saturated mono- and diacylglycerol neutral lipids and a paucity of residual polar lipids associated with purified hemozoin. Under conditions consistent with the DV, the neutral lipid mixture rapidly initiates heme crystallization with reversible, pH dependent quinoline inhibition. Formation of a heme-drug complex is required for drug entry into neutral lipid nanospheres and inhibition of heme crystallization. This work identifies neutral lipid nanospheres as both the microenvironment of heme crystallization and the nonaqueous, nonpolar site of quinoline inhibition.


3rd Place- Judith Easterbrook: Potential Mechanisms Mediating Persistence of Seoul Virus in Male Norway Rats

Summary:
Hantaviruses cause severe disease in humans and pathology is hypothesized to be mediated by sustained, elevated levels of proinflammatory cytokines. Rodents are the natural hosts for hantaviruses; unlike humans, rodents display no pathology during infection, yet remain persistently infected. This study examined whether Seoul virus suppresses rodent host immune responses that would allow persistent infection. Male rats were inoculated with Seoul virus and proinflammatory (interleukin (IL)-1, IL-6, and TNF) and anti-inflammatory (IL-10, IL-1 receptor antagonist (ra), and corticosterone) responses were assessed. Copies of Seoul virus were significantly elevated in the lung 15 and 30 days post inoculation (p.i.). Expression of splenic IL-1 was cyclical, with transcription elevated 3 and 60 days p.i., but reduced to baseline 15-30 days p.i. Interleukin-1 protein production was significantly below baseline 15-60 days p.i. Similar, but less dramatic, trends were observed for transcription of IL-6 and TNF. Expression of IL-10 and IL-1ra remained at baseline 3-30 days p.i., but was significantly elevated 60 days p.i. Synthesis of IL-10, however, was significantly suppressed 3-60 days p.i. Corticosterone concentrations remained low 3-30 days p.i., but were elevated at 60 days p.i. These data indicate that Seoul virus infection suppresses proinflammatory cytokine production. The reduction of proinflammatory immune responses does not correlate with elevation of anti-inflammatory factors produced by the host, including IL-10, IL-1ra, and corticosterone, suggesting that virus-induced immunosuppression may be involved.

Applied Research

1st Place- Xiaoyan Song: Association of Serum Ferritin and Mortality in Incident Hemodialysis Patients

Summary:

Background: Each year, about 300,000 patients in U.S. receive hemodialysis (HD) to treat end stage renal disease. Given that almost every HD patient suffers from anemia and thus requires recombinant human erythropoietin (EPO) treatment, intravenous (IV) iron therapy has become one of the most important adjunctive treatments in anemic HD patients. Although IV iron is effective in correcting anemia, excessive iron in human body increases patient's risk of developing infections and cardiovascular diseases. Epidemiological studies addressing iron and mortality in HD patients provided controversial evidences, partially because these studies only followed patients for less than 2 years which were insufficient to assess the causal effect of iron on mortality.

Objective: To examine the relationship between serum ferritin (SF), a marker of body iron storage, and all-cause mortality in incident HD patients.

Method: A prospective longitudinal cohort study. Eligible patients were incident HD patients who were enrolled in the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study, an ongoing prospective study that had followed 1,041 incident dialysis patients recruited from 81 clinics nationwide since 1995, and had baseline SF values that were measured within 3 months of dialysis onset. Baseline patient characteristics (age, gender, race, smoking, employment and marital status) and co-morbidity were collected through a self-administered questionnaire. Clinical laboratory values including SF were obtained from an electronic database. Death was prospectively identified from medical records, national Death Certificate Index database, and U.S. Renal Disease System. Statistical analyses included descriptive analysis to examine associations between SF (grouped into <100 mg/dL, 100~500 mg/dL, 500~800 mg/dL, and >800 mg/dL for the ease of clinical interpretation), death and covariates. Unadjusted and adjusted Cox regression model was used to determine the independent effect of SF on mortality. Laboratory values including inflammatory marker C-reactive protein (CRP) were adjusted as time-dependent covariates. To further illustrate a potential causal effect of iron on mortality, we analyzed a group of patients who survived for at least 6 months from dialysis onset and excluded SF values that were measured within 6 months before the events (death or censoring) occurred.

Results: Of 767 HD patients enrolled in the CHOICE study, 687 (89.6%) had baseline SF available and 614 (80.1%) survived for at least 6 months after dialysis onset. Patients in the four SF groups were similar in baseline age, race, smoking, marital and employment status, and education levels. Baseline SF was positively associated with CRP (p=0.04), but negatively associated with albumin (p<0.001). No statistical association was found between baseline SF and mortality in the analysis using either whole- or sub- group data. Cox regression model using whole-cohort data found no association between follow-up SF and mortality. Comparing to the reference group 100~500 mg/dL, Hazard Ratio (HR) was 0.74 (95% Confidence Interval (CI): 0.45~1.23), 1.02 (95% CI: 0.75~1.39), and 1.16 (95%CI: 0.93~1.45) for SF<100, 500~800, and >800 mg/dL groups, respectively. Cox regression using sub-cohort data and excluding SF measured in the last 6 months before events occurred revealed that SF <100 mg/dL was associated with elevated mortality (HR: 1.26, 95%CI: 1.01~1.57). The association remained statistically significant after adjusting for CRP and albumin.

Conclusion: We found that low, rather than high, SF was associated with increased mortality. Our results suggested a reverse causal effect when using SF as a marker of body iron to assess its relationship with mortality in HD patients. Further study was warranted to confirm this finding.


2nd Place- Joachim Bleys: Vitamin / Mineral Supplementation And The Progression Of Atherosclerosis. A Meta-Analysis Of Randomized Controlled Trials

Summary:
Joachim Bleys, MD, MPH; Edgar R. Miller III, MD, PhD; Roberto Pastor-Barriuso, PhD; Lawrence J. Appel, MD, MPH; Eliseo Guallar, MD, DrPH
From the Departments of Epidemiology and Medicine, and the Welch Center for Prevention, Epidemiology and Clinical Research, the Johns Hopkins Medical Institutions, Baltimore, MD (J.B., L.J.A., and E.G.), the National Institute on Aging / National Institutes of Health, Baltimore, MD (E.R.M.), and the Division of Biostatistics, National Center for Epidemiology, Instituto de Salud Carlos III, Madrid, Spain (RPB).

Abstract:
Background: Laboratory and observational studies suggested that antioxidant and B-vitamin supplementation may prevent atherosclerosis. Although trials have not shown a benefit of these supplements on clinical cardiovascular events, it is unknown whether they affect the progression of atherosclerosis as measured by imaging techniques.

Methods and results: We performed a meta-analysis of randomized controlled trials assessing the effect of vitamin / mineral supplementation on atherosclerosis progression. We searched MEDLINE, EMBASE, and CENTRAL for relevant studies. No language restrictions were applied. We separately analyzed trials using antioxidant compounds (vitamins E, C, beta-carotene or selenium) from trials using B-vitamins (folate, vitamin B6 or vitamin B12). The progression of atherosclerosis was evaluated by B-mode ultrasound, intravascular ultrasound, or angiography. Effect sizes were calculated for the difference in slope of atherosclerosis progression between participants assigned to supplements and those assigned to the control group. In trials not involving percutaneous transluminal coronary angioplasty (PTCA), the pooled effect size was -0.06 (95% CI, -0.20 to 0.09; 7 trials) for antioxidants, and -0.93 (95% CI, -2.11 to 0.26; 4 trials) for B-vitamins. In post-PTCA trials, the pooled relative risk for restenosis was 0.82 (95% CI, 0.54 to1.26; 3 trials) for antioxidants and 0.84 (95% CI, 0.34 to 2.07; 2 trials) for B-vitamins.

Conclusions: Our meta-analysis showed no evidence for a protective effect of antioxidant vitamin / mineral and B-vitamin supplementation on the progression of atherosclerosis, thus providing a mechanistic explanation for the lack of effect of these supplements on clinical cardiovascular events.

Key words: Meta-analysis, Antioxidants, Folate, Atherosclerosis, Prevention

3rd Place- Jeffrey Willis: Perceived Neonatal Morbidities in Rural Uttar Pradesh, India: Effects of a Community Mobilization and Behavior-Change Communication Intervention

Summary:
Objective: To test the effects of a community mobilization and behavior-change communication (BCC) intervention on perceived neonatal illnesses in rural Uttar Pradesh, India.

Background: Poor neonatal health is a barrier towards improving child survival. One mechanism of improving newborn health in low-resource, high mortality areas such as rural Uttar Pradesh, India, is mobilizing households to engage in community-based essential newborn health practices. Johns Hopkins University and King George Medical University in Lucknow, India, have implemented a community mobilization and BCC intervention that delivers a package of preventive essential newborn care messages to families and communities in rural Uttar Pradesh. It is hypothesized that this intervention will reduce the incidence of newborn illnesses.

Methods: The study was nested in a cluster-randomized trial of the impact of a package of essential newborn care in Shivgarh, a rural block of Uttar Pradesh. The study prospectively enrolled 802 mothers between February and August, 2005, and administered a structured questionnaire to recently delivered women in Hindi at the end of the neonatal period. Multiple logistic regression analysis was used to evaluate the statistical significance of the interventions on perceived neonatal illnesses.

Results: Newborns in the intervention area had significantly lower odds of perceived diarrhea [Adjusted Odds Ratio (OR) 0.66, 95% C.I. 0.46-0.95] and perceived skin-related complications [Adjusted OR 0.62, 95% C.I. 0.42-0.89)] compared to newborns in the comparison area. On average, the day in which the initial newborn illness was recognized was earlier among households in the comparison arm (10.2 8.0 days after birth) than households in the intervention arm (12.3 8.7 days) (p=0.01).

Conclusions: An intervention program focusing on essential preventive newborn health practices significantly reduced the perceived odds of diarrhea and skin-related complications in newborns during the neonatal period. Onset of neonatal illnesses may also have been delayed. Community mobilization and BCC interventions are important tools to reduce neonatal morbidities, although future research should consider using health professionals to more accurately document the changes in neonatal morbidity rates.


Scientific Posters Submitted to the 2006 Delta Omega Competition

1. J. Morel Symons A case-crossover study of fine particulate matter air pollution and congestive heart failure hospitalization
2. Konstantinos Tsilidis Association of obesity, insulin resistance, and other features of the metabolic syndrome with colorectal adenoma in Clue II
3. Fan Li The invalidity in stratification of affected-sib-pairs on covariates with possible genetic determinants: problem and solution strategies
4. Ani Manichaikul Don't Use the Bootstrap for QTL Mapping
5. Mia Papas Dietary intake according to fast food restaurant use among adolescents participating in CLUE II
6. Edwina Yeung Family History of Coronary Heart Disease and the Risk of Incident Type 2 Diabetes
7. Nagesh Borse Bibliometric Analysis of Unintentional Injuries in Low and Middle Income Countries
8. Zohra Patel Community Neonatal Death Audits: a participatory process to mobilize and empower the community for collective action
9. Larissa Jennings Community health workers in Bangladesh: Negotiation and counseling in newborn care preparedness
10. Jonathan Brown Screening for child and adolescent mental health problems in primary care using child, parent, and teacher informants
11. Ali Alam Plasma Levels Of B-Type Natriuretic Peptide In Patients With Unstable Angina Pectoris Or Acute Myocardial Infarction: Prognostic Significance And Therapeutic Implications
12. Caren Chancey Combination of antibodies to CD18 and ICAM-1 reduces transmission of cell-associated HIV-1
13. Juhee Cho Overweight and Obesity Among Korean Americans: Are they really at low risk?
14. Ji Wan Park Association between interferon regulatoruy factor 6 (IRF6) and nonsyndromic cleft lip with or without cleft palate (CL/P) in 4 populations
15. Hossein Bahrami Natural History of Retinitits Pigmentosa; Changes in Visual Acuity, Contrast Sensitivity, and Visual Field
16. Alexander Balbir Role of Genetics in the Development of Sleep-Disordered Breathing
17. Ashley Schempf The Contribution of Preterm Birth to the Black-White Infant Mortality Gap, 1990 and 2000
18. John Pisciotta Hemozoin Formation and Detection in P. falciparum
19. Jeffrey Willis Perceived Neonatal Morbidities in Rural Uttar Pradesh, India: Effects of a Community Mobilization and Behavior-Change Communication Intervention
20. Neal Burton In vivo Attenuation of the Parkinsonian Phenotype by Induction of transcription factor Nrf2
21. Bryan James Education and executive function in the Baltimore Memory Study
22. Kristin Nicodemus NRG1 gene and the Risk of Schizophrenia: Does it Depend on Statistical Epistasis between NRG1 Protein-Interaction Partners ERBB4, CHRNA7, AKT1, DLG4, CAPON and NOS1?
23. Joachim Bleys Vitamin / Mineral Supplementation And The Progression Of Atherosclerosis. A Meta-Analysis Of Randomized Controlled Trials
24. Judy Easterbrook Potential Mechanisms Mediating Persistence of Seoul Virus in Male Norway Rats
25. Leora Vegosen Seasonal Birth Patterns in Subgroups of Myositis Suggest a Role for Perinatal Environmental Factors in Etiology
26. Alezandria Turner Designing HOPE: an intervention to address the mental health needs of Baltimore youth
27. Kimberly Walton The Impact of Screening Brief Intervention & Referral To Treatment (SBIRT) On Emergency Department (ED) Patients Alcohol Use
28. Caroline Fichtenberg The impact of differential mixing by sexual activity on racial/ethnic STI disparities: A simulation study
29. Xiaoyan Song Association of Serum Ferritin and Mortality in Incident Hemodialysis Patient
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