Overestimation of Vitamin A Supplementation Coverage from District Tally Sheets Demonstrates Importance of Population-Based Surveys for Program Improvement: Lessons from Tanzania

Background

Tanzania has conducted a national twice-yearly Vitamin A supplementation (VAS) campaign since 2001. Administrative coverage rates based on tally sheets consistently report >90% coverage; however the accuracy of these rates are uncertain due to potential errors in tally sheets and their aggregation, incomplete or inaccurate reporting from distribution sites, and underestimating the target population.

Objectives

The post event coverage survey in Mainland Tanzania sought to validate tally-sheet based national coverage estimates of VAS and deworming for the June 2010 mass distribution round, and to characterize children missed by the national campaign.

Methods

WHO/EPI randomized cross-sectional cluster sampling methodology was adapted for this study, using 30 clusters by 40 individuals (n = 1200), in addition to key informant interviews. Households with children 6–59 months of age were included in the study (12–59 months for deworming analysis). Chi-squared tests and logistic regression analysis were used to test differences between children reached and not reached by VAS. Data was collected within six weeks of the June 2010 round.

Results

A total of 1203 children, 58 health workers, 30 village leaders and 45 community health workers were sampled. Preschool VAS coverage was 65% (95% CI: 62.7–68.1), approximately 30% lower than tally-sheet coverage estimates. Factors associated with not receiving VAS were urban residence [OR = 3.31; p = 0.01], caretakers who did not hear about the campaign [OR = 48.7; p<0.001], and Muslim households [OR<3.25; p<0.01]. There were no significant differences in VAS coverage by child sex or age, or maternal age or education.

Conclusion

Coverage estimation for vitamin A supplementation programs is one of most powerful indicators of program success. National VAS coverage based on a tally-sheet system overestimated VAS coverage by ∼30%. There is a need for representative population-based coverage surveys to complement and validate tally-sheet estimates.     

PARTAKE Survey of Public Knowledge and Perceptions of Clinical Research in India

Background

A public that is an informed partner in clinical research is important for ethical, methodological, and operational reasons. There are indications that the public is unaware or misinformed, and not sufficiently engaged in clinical research but studies on the topic are lacking. PARTAKE – Public Awareness of Research for Therapeutic Advancements through Knowledge and Empowerment is a program aimed at increasing public awareness and partnership in clinical research. The PARTAKE Survey is a component of the program.

Objective

To study public knowledge and perceptions of clinical research.

Methods

A 40-item questionnaire combining multiple-choice and open-ended questions was administered to 175 English- or Hindi-speaking individuals in 8 public locations representing various socioeconomic strata in New Delhi, India.

Results

Interviewees were 18–84 old (mean: 39.6, SD±16.6), 23.6% female, 68.6% employed, 7.3% illiterate, 26.3% had heard of research, 2.9% had participated and 58.9% expressed willingness to participate in clinical research. The following perceptions were reported (% true/% false/% not aware): ‘research benefits society’ (94.1%/3.5%/2.3%), ‘the government protects against unethical clinical research’ (56.7%/26.3%/16.9%), ‘research hospitals provide better care’ (67.2%/8.7%/23.9%), ‘confidentiality is adequately protected’ (54.1%/12.3%/33.5%), ‘participation in research is voluntary’ (85.3%/5.8%/8.7%); ‘participants treated like ‘guinea pigs’’ (20.7%/53.2%/26.0%), and ‘compensation for participation is adequate’ (24.7%/12.9%/62.3%).

Conclusions

Results suggest the Indian public is aware of some key features of clinical research (e.g., purpose, value, voluntary nature of participation), and supports clinical research in general but is unaware of other key features (e.g., compensation, confidentiality, protection of human participants) and exhibits some distrust in the conduct and reporting of clinical trials. Larger, cross-cultural surveys are required to inform educational programs addressing these issues.     

Leptin differentially regulates NPY secretion in hypothalamic cell lines through distinct intracellular signal transduction pathways

Leptin acts as a key peripheral hormone in distinct neurons in the hypothalamus to modulate both reproductive function and energy homeostasis. The control of neuropeptide Y (NPY) secretion is an example of a process that can be differentially regulated by leptin. In order to further understand these distinct modulatory effects, we have used immortalized, neuronal hypothalamic cell lines expressing NPY, mHypoE-38 and mHypoE-46. We found that these cell lines express the endogenous leptin receptor, ObRb, and secrete detectable levels of NPY. We exposed the neurons to 100nM leptin for 1h and determined that the basal levels of NPY in the cell lines were differentially regulated: NPY secretion was inhibited in mHypoE-46 neurons, whereas NPY secretion was induced in the mHypoE-38 neurons. In order to determine the mechanisms involved in the divergent regulation of NPY release, we analyzed the activity of a number of signaling components using phospho-specific antibodies directed towards specific proteins in the MAP kinase, PI3K, and AMPK pathways, among others. We found that leptin activated a different combination of second messengers in each cell line. Importantly, we could link the regulation of NPY secretion to different signaling pathways, AMPK in the mHypoE-46 and both MAPK and PI3K in the mHypoE-38 neurons. This is the first demonstration that leptin can specifically regulate individual NPY neuron secretory responses through distinct signaling pathways.     

Gene stacking strategies with doubled haploids derived from biparental crosses: theory and simulations assuming a finite number of loci

Recent progress in genotyping and doubled haploid (DH) techniques has created new opportunities for development of improved selection methods in numerous crops. Assuming a finite number of unlinked loci (ℓ) and a given total number (n) of individuals to be genotyped, we compared, by theory and simulations, three methods of marker-assisted selection (MAS) for gene stacking in DH lines derived from biparental crosses: (1) MAS for high values of the marker score (T, corresponding to the total number of target alleles) in the F₂ generation and subsequently among DH lines derived from the selected F₂ individual (Method 1), (2) MAS for augmented F₂ enrichment and subsequently for T among DH lines from the best carrier F₂ individual (Method 2), and (3) MAS for T among DH lines derived from the F₁ generation (Method 3). Our objectives were to (a) determine the optimum allocation of resources to the F₂ ( n₁^* \, n_{1}^{*} ) and DH generations (n - n₁^* ) (n - n_{1}^{*} ) for Methods 1 and 2 by simulations, (b) compare the efficiency of all three methods for gene stacking by simulations, and (c) develop theory to explain the general effect of selection on the segregation variance and interpret our simulation results. By theory, we proved that for smaller values of ℓ, the segregation variance of T among DH lines derived from F₂ individuals, selected for high values of T, can be much smaller than expected in the absence of selection. This explained our simulation results, showing that for Method 1, it is best to genotype more F₂ individuals than DH lines ($ n_{1}^{*} :n > 0.5 $ n_{1}^{*} :n > 0.5 ), whereas under Method 2, the optimal ratio n₁^* :n n_{1}^{*} :n was close to 0.5. However, for ratios deviating moderately from the optimum, the mean [`(X)] \overline{X} of T in the finally selected DH line ( T<sub>\textDH</sub><sup>*</sup> T_{\text{DH}}^{*} ) was hardly reduced. Method 3 had always the lowest mean [`(X)] \overline{X} of T_\textDH^* T_{\text{DH}}^{*} except for small numbers of loci (ℓ = 4) and is favorable only if a small number of loci are to be stacked in one genotype and/or saving one generation is of crucial importance in cultivar development. Method 2 is under most circumstances the superior method, because it generally showed the highest mean [`(X)] \overline{X} and lowest SD of T_\textDH^* T_{\text{DH}}^{*} for the finally selected DH.     

Campylobacter jejuni strains compete for colonization in broiler chicks

Campylobacter jejuni isolates possess multiple adhesive proteins termed adhesins, which promote the organism's attachment to epithelial cells. Based on the proposal that one or more adhesins are shared among C. jejuni isolates, we hypothesized that C. jejuni strains would compete for intestinal and cecal colonization in broiler chicks. To test this hypothesis, we selected two C. jejuni strains with unique SmaI pulsed-field gel electrophoresis macrorestriction profiles and generated one nalidixic acid-resistant strain (the F38011 Nal(r) strain) and one streptomycin-resistant strain (the 02-833L Str(r) strain). In vitro binding assays revealed that the C. jejuni F38011 Nal(r) and 02-833L Str(r) strains adhered to LMH chicken hepatocellular carcinoma epithelial cells and that neither strain influenced the binding potential of the other strain at low inoculation doses. However, an increase in the dose of the C. jejuni 02-833L Str(r) strain relative to that of the C. jejuni F38011 Nal(r) strain competitively inhibited the binding of the C. jejuni F38011 Nal(r) strain to LMH cells in a dose-dependent fashion. Similarly, the C. jejuni 02-833L Str(r) strain was found to significantly reduce the efficiency of intestinal and cecal colonization by the C. jejuni F38011 Nal(r) strain in broiler chickens. Based on the number of bacteria recovered from the ceca, the maximum number of bacteria that can colonize the digestive tracts of chickens may be limited by host constraints. Collectively, these data support the hypothesis that C. jejuni strains compete for colonization in chicks and suggest that it may be possible to design novel intervention strategies for reducing the level at which C. jejuni colonizes the cecum.     

Bleomycin treatment causes enhancement of virus replication in the lungs of SHIV-infected macaques

Pneumonia is a major complication of human immunodeficiency virus (HIV) pathogenesis but it develops only after prolonged infection. We used the macaque model to explore a hypothesis that the disease is a two-stage process, the first stage being establishment of the viral infection in the lung and the second being amplification of virus replication by host factors induced by chemical agents or opportunistic pathogens in the lung. Bleomycin, a chemical known to induce diffuse alveolar damage and pulmonary fibrosis with accumulation of macrophages and a rich T helper type 2 (Th2) cytokine environment, was inoculated intratracheally into five of eight SHIV 89.6P-infected macaques and into one uninfected macaque. Three additional simian HIV (SHIV)-infected macaques without bleomycin treatment served as untreated virus controls. Although none of the animals became clinically ill, bleomycin induced classical host responses in the lungs of all the treated, virus-infected macaques. There was enhanced production of the chemokine, monocyte chemotactic protein-1 (MCP-1), that had previously been shown to cause enhanced replication of the virus. Four of the five treated animals developed more productive SHIV infection in the lungs compared with the infected untreated animals. Enhanced virus replication was found primarily in infiltrating macrophages. Enhanced replication of the virus in the lungs was associated with host factors induced by the drug and supported the hypothesis for a two-stage process of pulmonary pathogenesis.