Characterization of rag1 mutant zebrafish leukocytes

<p>Abstract</p> <p>Background</p> <p>Zebrafish may prove to be one of the best vertebrate models for innate immunology. These fish have sophisticated immune components, yet rely heavily on innate immune mechanisms. Thus, the development and characterization of mutant and/or knock out zebrafish are critical to help define immune cell and immune gene functions in the zebrafish model. The use of Severe Combined Immunodeficient (SCID) and <it>recombination activation gene </it>1 and 2 mutant mice has allowed the investigation of the specific contribution of innate defenses in many infectious diseases. Similar zebrafish mutants are now being used in biomedical and fish immunology related research. This report describes the leukocyte populations in a unique model, <it>recombination activation gene 1</it>^-/-mutant zebrafish (<it>rag</it>1 mutants).</p> <p>Results</p> <p>Differential counts of peripheral blood leukocytes (PBL) showed that <it>rag</it>1 mutants had significantly decreased lymphocyte-like cell populations (34.7%) compared to wild-types (70.5%), and significantly increased granulocyte populations (52.7%) compared to wild-types (17.6%). Monocyte/macrophage populations were similar between mutants and wild-types, 12.6% and 11.3%, respectively. Differential leukocyte counts of <it>rag</it>1 mutant kidney hematopoietic tissue showed a significantly reduced lymphocyte-like cell population (8%), a significantly increased myelomonocyte population (57%), 34.8% precursor cells, and 0.2% thrombocytes, while wild-type hematopoietic kidney tissue showed 29.4% lymphocytes/lymphocyte-like cells, 36.4% myelomonocytes, 33.8% precursors and 0.5% thrombocytes.</p> <p>Flow cytometric analyses of kidney hematopoietic tissue revealed three leukocyte populations. Population A was monocytes and granulocytes and comprised 34.7% of the gated cells in <it>rag</it>1 mutants and 17.6% in wild-types. Population B consisted of hematopoietic precursors, and comprised 50% of the gated cells for <it>rag</it>1 mutants and 53% for wild-types. Population C consisted of lymphocytes and lymphocyte-like cells and comprised 7% of the gated cells in the <it>rag</it>1 mutants and 26% in the wild-types.</p> <p>Reverse transcriptase polymerase chain reaction (RT-PCR) assays demonstrated <it>rag</it>1 mutant kidney hematopoietic tissue expressed mRNA encoding Non-specific Cytotoxic cell receptor protein-1 (NCCRP-1) and Natural Killer (NK) cell lysin but lacked T cell receptor (TCR) and immunoglobulin (Ig) transcript expression, while wild-type kidney hematopoietic tissue expressed NCCRP-1, NK lysin, TCR and Ig transcript expression.</p> <p>Conclusion</p> <p>Our study demonstrates that in comparison to wild-type zebrafish, <it>rag</it>1 mutants have a significantly reduced lymphocyte-like cell population that likely includes Non-specific cytotoxic cells (NCC) and NK cells (and lacks functional T and B lymphocytes), a similar macrophage/monocyte population, and a significantly increased neutrophil population. These zebrafish have comparable leukocyte populations to SCID and <it>rag </it>1 and/or 2 mutant mice, that possess macrophages, natural killer cells and neutrophils, but lack T and B lymphocytes. <it>Rag</it>1 mutant zebrafish will provide the platform for remarkable investigations in fish and innate immunology, as <it>rag </it>1 and 2 mutant mice did for mammalian immunology.</p

A Computer-Aided Decomposition of the Complete Digraph into Orientations of K4 − e with a Double Edge

The abstract is available as an Additional File

Community-based approaches for neonatal survival: meta-analyses of randomized trial data.

OBJECTIVE: To analyse the impact of community approaches to improving newborn health and survival in low-resource countries. METHODS: We updated previous meta-analyses of published cluster randomized trials of community-based interventions for neonatal survival. For each study we extracted baseline data on the context: geographical area; available facilities and staffing; immediate breastfeeding and facility births; and neonatal mortality. We also extracted data on the primary outcome (neonatal survival) and intermediate outcomes of the interventions (changes in immediate breastfeeding and facility births). We used forest plots and pooled sub-group analysis to seek patterns in associations between the effect size and the context or type of intervention (home-based counselling or women's groups). FINDINGS: We included 17 trials, spanning years from 2001 to 2013. A 25% reduction in neonatal mortality (relative risk, RR: 0.75; 95% confidence interval, CI: 0.69-0.80) was found when pooling six studies in settings with 44 or more deaths per 1000 live births. In lower-mortality settings (pooling six studies with 32 or fewer deaths per 1000 live births) there was no evidence of an effect. We observed some evidence that community approaches had a stronger effect in south Asia than in sub-Saharan Africa. Community approaches had a lower impact on neonatal mortality in settings where at least 44% of women delivered in a facility. CONCLUSION: As neonatal mortality declined, the impact of community approaches on survival appeared to be lower, and the role of these approaches in supporting newborn care in weak health systems may need to be re-examined

Birth preparedness and place of birth in Tandahimba district, Tanzania: what women prepare for birth, where they go to deliver, and why.

BACKGROUND: As making preparations for birth and health facility delivery are behaviours linked to positive maternal and newborn health outcomes, we aimed to describe what birth preparations were made, where women delivered, and why. METHODS: Outcomes were tabulated using data derived from a repeated sample (continuous) quantitative household survey of women aged 13-49 who had given birth in the past year. Insights into why behaviours took place emerged from analysis of in-depth interviews (12) and birth narratives (36) with recently delivered mothers and male partners. RESULTS: Five hundred-twenty three women participated in the survey from April 2012-November 2013. Ninety-five percent (496/523) of women made any birth preparations for their last pregnancy. Commonly prepared birth items were cotton gauze (93 %), a plastic cover to deliver on (84 %), gloves (72 %), clean clothes (70 %), and money (42 %). Qualitative data suggest that preparation of items used directly during delivery was perceived as necessary to facilitate good care and prevent disease transmission. Sixty-eight percent of women gave birth at a health facility, 30 % at home, and 2 % on the way to a health facility. Qualitative data suggested that health facility delivery was viewed positively and that women were inclined to go to a health facility because of a perception of: increased education about delivery and birth preparedness; previous health facility delivery; and better availability and accessibility of facilities in recent years. Perceived barriers: were a lack of money; absent health facility staff or poor provider attitudes; women perceiving that they were unable to go to a health facility or arrange transport on their own; or a lack of support of pregnant women from their partners. CONCLUSIONS: The majority of women made at least some birth preparations and gave birth in a health facility. Functional items needed for birth seem to be given precedence over practices like saving money. As such, maintaining education about the importance of these practices, with an emphasis on emergency preparedness, would be valuable. Alongside education delivered as part of focussed antenatal care, community-based interventions that aim to increase engagement of men in birth preparedness, and support agency among women, are recommended

Sexual behaviour, changes in sexual behaviour and associated factors among women at high risk of HIV participating in feasibility studies for prevention trials in Tanzania.

INTRODUCTION: Risk reduction towards safer behaviour is promoted after enrolment in HIV prevention trials. We evaluated sexual behaviour, changes in sexual behaviour and factors associated with risky behaviour after one-year of follow-up among women enrolled in HIV prevention trials in Northern Tanzania. METHODS: Self-reported information from 1378 HIV-negative women aged 18-44 enrolled in microbicide and vaccine feasibility studies between 2008-2010,was used to assess changes in behaviour during a 12-month follow-up period. Logistic regression with random intercepts was used to estimate odds ratios for trends in each behaviour over time. A behavioural risk score was derived from coefficients of three behavioural variables in a Poisson regression model for HIV incidence and thereafter, dichotomized to risky vs less-risky behaviour. Logistic regression was then used to identify factors associated with risky behaviour at 12 months. RESULTS: At baseline, 22% reported multiple partners, 28% were involved in transactional sex and only 22% consistently used condoms with non-regular partners. The proportion of women reporting multiple partners, transactional sex and high-risk sex practices reduced at each 3-monthly visit (33%, 43% and 47% reduction in odds per visit respectively, p for linear trend <0.001 for all), however, there was no evidence of a change in the proportion of women consistently using condoms with non-regular partners (p = 0.22). Having riskier behaviours at baseline, being younger than 16 years at sexual debut, having multiple partners, selling sex and excessive alcohol intake at baseline were strongly associated with increased odds of risky sexual behaviour after 12 months (p<0.005 for all). CONCLUSION: An overall reduction in risky behaviours over time was observed in HIV prevention cohorts. Risk reduction counselling was associated with decreased risk behaviour but was insufficient to change behaviours of all those at highest risk. Biological HIV prevention interventions such as PrEP for individuals at highest risk, should complement risk reduction counselling so as to minimize HIV acquisition risk

Illness recognition and care-seeking for maternal and newborn complications in rural eastern Uganda.

BACKGROUND: To enhance understanding of the roles of community-based initiatives in poor rural societies, we describe and explore illness recognition, decision-making, and appropriate care-seeking for mothers and newborn illnesses in two districts in eastern Uganda where in one implementation district, a facility and community quality improvement approach was implemented. METHODS: This was a cross-sectional study using qualitative methods. We conducted 48 event narratives: eight maternal and newborn deaths and 16 maternal and newborn illnesses. Additionally, we conducted six FGDs with women's saving groups and community leaders. Qualitative data were analyzed thematically using Atlas.ti software. RESULTS: Women and caretakers reported that community initiatives including the presence of community health workers and women's saving groups helped in enhancing illness recognition, decision-making, and care-seeking for maternal and newborn complications. Newborn illness seemed to be less well understood, and formal care was often delayed. Care-seeking was complicated by accessing several stations from primary to secondary care, and often, the hospital was reached too late. CONCLUSIONS: Our qualitative study suggests that community approaches may play a role in illness recognition, decision-making, and care-seeking for maternal and newborn illness. The role of primary facilities in providing care for maternal and newborn emergencies might need to be reviewed