Faculty Bibliography

INTRODUCTION: Rates of tuberculosis in Central Asia are extremely high, and even more alarming are the very high rates of multidrug-resistant tuberculosis (MDR-TB) in Kazakhstan, Uzbekistan, Tajikistan and Kyrgyzstan. In addition, rates of HIV infection related to injection drug use seems to be rising as well, thus creating conditions for a potentially devastating co-epidemic of TB/HIV and MDR-TB/HIV which would have terrible consequences for public health in these countries. CURRENT STATUS: In many countries of Central Asia, diagnosis of tuberculosis still rests on clinical grounds or simple technologies such as chest radiograph and sputum smear examination. Modern molecular techniques such as GenExpert are being introduced in Kazakhstan and Uzbekistan, and perhaps soon in Kyrgyzstan. Treatment of TB is still often centered around prolonged inpatient stay at TB hospitals. Only a minority of patients with HIV infection are receiving ART, and TB and HIV services are not well integrated. Needle exchange programs are becoming increasingly available, but opioid substitution therapy is rarely used in Central Asia. TB, drug treatment and HIV services are generally not well-integrated. CONCLUSIONS: To combat this developing storm, integration of TB services, HIV care, and substance abuse treatment programs is needed urgently to allow efficient and effective diagnosis and treatment of these conditions in a coordinated manner.

BACKGROUND: SLX4 encodes a DNA repair protein that regulates three structure-specific endonucleases and is necessary for resistance to DNA crosslinking agents, topoisomerase I and poly (ADP-ribose) polymerase (PARP) inhibitors. Recent studies have reported mutations in SLX4 in a new subtype of Fanconi anemia (FA), FA-P. Monoallelic defects in several FA genes are known to confer susceptibility to breast and ovarian cancers. METHODS AND RESULTS: To determine if SLX4 is involved in breast cancer susceptibility, we sequenced the entire SLX4 coding region in 738 (270 Jewish and 468 non-Jewish) breast cancer patients with 2 or more family members affected by breast cancer and no known BRCA1 or BRCA2 mutations. We found a novel nonsense (c.2469G>A, p.W823*) mutation in one patient. In addition, we also found 51 missense variants [13 novel, 23 rare (MAF<0.1%), and 15 common (MAF>1%)], of which 22 (5 novel and 17 rare) were predicted to be damaging by Polyphen2 (score = 0.65-1). We performed functional complementation studies using p.W823* and 5 SLX4 variants (4 novel and 1 rare) cDNAs in a human SLX4-null fibroblast cell line, RA3331. While wild type SLX4 and all the other variants fully rescued the sensitivity to mitomycin C (MMC), campthothecin (CPT), and PARP inhibitor (Olaparib) the p.W823* SLX4 mutant failed to do so. CONCLUSION: Loss-of-function mutations in SLX4 may contribute to the development of breast cancer in very rare cases.

BACKGROUND: Low-contrast letter acuity and optical coherence tomography (OCT) capture visual dysfunction and axonal loss in adult-onset multiple sclerosis (MS), and have been proposed as secondary outcome metrics for therapeutic trials. Clinical trials will soon be launched in pediatric MS, but such outcome metrics have not been well-validated in this population. OBJECTIVES: To determine whether MS onset during childhood and adolescence is associated with measurable loss of visual acuity and thinning of the retinal nerve fiber layer (RNFL), whether such features are noted only in the context of clinical optic nerve inflammation (optic neuritis, ON) or are a feature of MS even in the absence of optic nerve relapses, and to define the optimal methods for such detection. STUDY DESIGN: Cross-sectional study. METHODS: Monocular and binocular high- and low-contrast letter acuity and contrast sensitivity were assessed in a cross-sectional cohort of children (ages 5 to 17 years) with MS (N=22 patients, 44 eyes; 8 patients with a history of ON) and disease-free controls (N=29 patients; 58 eyes) from three academic centers. Binocular summation was determined by calculating the number of letters correctly identified using the binocular score minus the better eye score for each visual test. RNFL thickness was measured using OCT (Stratus OCT-3). Results were analyzed in terms of "eyes" as: MS ON+, MS ON-, and control eyes. Generalized estimating equation (GEE) regression models were used to compare patients to controls. RESULTS: Traditional high-contrast visual acuity scores did not differ between MS ON+, MS ON-, and controls eyes. MS ON+ eyes had decreased monocular (p<0.001) and decreased binocular (p=0.007) low-contrast letter acuity (Sloan 1.25% contrast charts) scores. Monocular visual acuity did not differ when comparing MS ON- and control eyes. The magnitude of binocular summation using low-contrast charts was similar for pediatric MS participants and controls and was not diminished in children with a history of ON. While the mean RNFL thickness for all MS eyes (103+/-17 mum) trended lower when compared to corresponding measures in control eyes (109+/-9 mum, p=0.085), we confirmed a highly significant reduction in mean RNFL thickness in MS eyes with a history of ON (86+/-22 mum, p<0.001). RNFL thickness of MS ON- eyes in pediatric MS patients (109+/-11 mum) did not differ from controls (p=0.994). CONCLUSIONS: Low-contrast letter acuity detects subtle visual loss in MS patients with prior ON, consistent with incomplete recovery, a finding further supported by RNFL loss in ON affected eyes. In MS patients with prior unilateral ON, binocular acuity is decreased; however, the magnitude of binocular summation is preserved, unlike adult-onset MS who exhibit a reduced capacity for visual compensation in the context of unilateral injury. Also unlike findings in adult-onset MS, we did not demonstrate RNFL thinning in ON- eyes of children and adolescents with MS. Further validation is required to confirm whether neurodegeneration of visual pathways occurs in the absence of relapse, and thus whether OCT will serve as a sensitive metric for such pathology in the pediatric and adolescent MS context.

BACKGROUND: School programs can be effective in modifying knowledge, attitudes, and habits relevant to long-term risk of chronic diseases associated with sedentary lifestyles. As part of a long-term research strategy, we conducted an educational intervention in preschool facilities to assess changes in preschoolers' knowledge, attitudes, and habits toward healthy eating and living an active lifestyle. METHODS: Using a cluster design, we randomly assigned 14 preschool facilities in Bogota, Colombia to a 5-month educational and playful intervention (7 preschool facilities ) or to usual curriculum (7 preschool facilities ). A total of 1216 children aged 3-5 years, 928 parents, and 120 teachers participated. A structured survey was used at baseline, at the end of the study, and 12 months later to evaluate changes in knowledge, attitudes, and habits. RESULTS: Children in the intervention group showed a 10.9% increase in weighted score, compared with 5.3% in controls. The absolute adjusted difference was 3.90 units (95% confidence interval [CI], 1.64-6.16; P <.001). Among parents, the equivalent statistics were 8.9% and 3.1%, respectively (absolute difference 4.08 units; 95% CI, 2.03 to 6.12; P <.001), and among teachers, 9.4% and 2.5%, respectively (absolute difference 5.36 units; 95% CI, -0.29-11.01; P = .06). In the intervened cohort 1 year after the intervention, children still showed a significant increase in weighted score (absolute difference of 6.38 units; P <.001). CONCLUSIONS: A preschool-based intervention aimed at improving knowledge, attitudes, and habits related to healthy diet and active lifestyle is feasible, efficacious, and sustainable in very young children.

Current models incompletely risk-stratify patients with acute chest pain. In this study, N-terminal pro-B-type natriuretic peptide and cystatin C were incorporated into a contemporary chest pain triage algorithm in a clinically stratified population to improve acute coronary syndrome discrimination. Adult patients with chest pain presenting without myocardial infarction (n = 382) were prospectively enrolled from 2008 to 2009. After clinical risk stratification, N-terminal pro-B-type natriuretic peptide and cystatin C were measured and standard care was performed. The primary end point was the result of a clinical stress test. The secondary end point was any major adverse cardiac event at 6 months. Associations were determined through multivariate stratified analyses. In the low-risk group, 76 of 78 patients with normal levels of the 2 biomarkers had normal stress test results (negative predictive value 97%). Normal biomarkers predicted normal stress test results with an odds ratio of 10.56 (p = 0.006). In contrast, 26 of 33 intermediate-risk patients with normal levels of the 2 biomarkers had normal stress test results (negative predictive value 79%). Biomarkers and stress test results were not associated in the intermediate-risk group (odds ratio 2.48, p = 0.09). There were 42 major adverse cardiac events in the overall cohort. No major adverse cardiac events occurred at 6 months in the low-risk subgroup that underwent stress testing. In conclusion, N-terminal pro-B-type natriuretic peptide and cystatin C levels predict the results of stress tests in low-risk patients with chest pain but should not be substituted for stress testing in intermediate-risk patients. There is potential for their use in the early discharge of low-risk patients after clinical risk stratification.

BACKGROUND: Educational interventions in preschool children could improve dietary behavior and physical activity, and prevent unhealthy body weights in low- and middle-income countries. Previously, we have reported the beneficial impact of an educational intervention in preschoolers in a 6-month trial. We now report extended results after 36 months. METHODS: Evaluating the cohort of previously intervened children, baseline measurements were made in May 2009 in 14 preschool facilities in Usaquen (Bogota, Colombia). Follow-up measurements were performed at 18 and 36 months. The primary outcome was the mean change in children's knowledge and attitudes scores regarding healthy eating and living an active lifestyle, including habits scores related to physical activity. Secondary outcomes were the change over time of children's nutritional status and the mean change in parent's knowledge, attitudes, and habits. RESULTS: We included 1216 children, 3-5 years of age, and 928 parents. After adjusting by sex and age of children, socioeconomic status, age of parents, and age and education level of teachers, we found a significant increase in mean knowledge, attitudes, and habits scores at 36 months, compared with baseline: 87.94 vs 76.15 (P <.001); 86.39 vs 57.03 (P <.001); and 66.29 vs 48.72 (P <.001), respectively. We observed a similar increase in knowledge and attitude scores in parents: 73.45 vs 70.01 (P <.001); and 78.08 vs 74.65 (P <.001). The proportion of eutrophic children increased from 62.1% at baseline to 75.0% at 36 months (P <.0001). CONCLUSIONS: After 36 months, the educational intervention maintained a beneficial trend toward a healthy lifestyle in children and their parents.

The last decades of neuroscience research have produced immense progress in the methods available to understand brain structure and function. Social, cognitive, clinical, affective, economic, communication, and developmental neurosciences have begun to map the relationships between neuro-psychological processes and behavioral outcomes, yielding a new understanding of human behavior and promising interventions. However, a limitation of this fast moving research is that most findings are based on small samples of convenience. Furthermore, our understanding of individual differences may be distorted by unrepresentative samples, undermining findings regarding brain-behavior mechanisms. These limitations are issues that social demographers, epidemiologists, and other population scientists have tackled, with solutions that can be applied to neuroscience. By contrast, nearly all social science disciplines, including social demography, sociology, political science, economics, communication science, and psychology, make assumptions about processes that involve the brain, but have incorporated neural measures to differing, and often limited, degrees; many still treat the brain as a black box. In this article, we describe and promote a perspective--population neuroscience--that leverages interdisciplinary expertise to (i) emphasize the importance of sampling to more clearly define the relevant populations and sampling strategies needed when using neuroscience methods to address such questions; and (ii) deepen understanding of mechanisms within population science by providing insight regarding underlying neural mechanisms. Doing so will increase our confidence in the generalizability of the findings. We provide examples to illustrate the population neuroscience approach for specific types of research questions and discuss the potential for theoretical and applied advances from this approach across areas.