88 research outputs found
Unwanted Fertility Experience, HIV Status and Post-partum Contraceptive Use in a PMTCT Population in Durban, South Africa
The HIV prevalence in South Africa is 17.1% and a majority of HIV infected adults are women. One of the government's strategies to avert new HIV infections is the prevention of unwanted pregnancies in HIV positive women through contraceptive use. Therefore, understanding how unwanted fertility and HIV status affect contraceptive use is important to meeting this goal. The purpose of this mixed methods dissertation is to understand how unwanted fertility experience, HIV status and health facility factors affect women's contraceptive use in the post-partum period. The specific aims are: Aim 1: To examine whether knowledge of HIV status affects women's modern contraceptive use post-partum, Aim 2: To determine whether unwanted fertility and HIV status affect post-partum modern contraceptive use and intent and Aim 3: To explore health facility factors including client-provider interactions around contraception, counselor's knowledge about contraceptive methods, client waiting times and other health facility factors affecting modern contraceptive use post-partum. Quantitative methods were used for Aims 1 and 2 using a sample of sexually active post-partum women from an urban township outside of Durban, South Africa. Several multivariate logistic regression models were used to examine intent to use contraceptives at baseline and unwanted fertility experience, HIV status and post-partum contraceptive use at 14 weeks. Qualitative methods were used for Aim 3. In-depth interviews were conducted with clients and providers to identify health facility factors influencing in post-partum contraceptive use. Results from the quantitative paper demonstrate that intent did not predict post-partum contraceptive use, HIV status had a direct, but not moderating, effect on post-partum contraceptive use and that women experiencing unwanted fertility were less likely to use contraceptives post-partum. The measure of unwanted fertility likely underestimated unwanted fertility experience in this population. Findings from the qualitative paper indicate areas where clinic contraceptive programs can improve post-partum contraceptive use. Educating nurses about contraceptive initiation and more permanent methods, such as sterilization, could improve post-partum contraceptive use and reduce costs and patient overload. Creating opportunities for nurses and clients to have more in-depth discussions about contraceptive methods, side effects, condoms and STIs would improve post-partum contraceptive use
Gastric pouches and the mucociliary sole: setting the stage for nervous system evolution.
Prerequisite for tracing nervous system evolution is understanding of the body plan, feeding behaviour and locomotion of the first animals in which neurons evolved. Here, a comprehensive scenario is presented for the diversification of cell types in early metazoans, which enhanced feeding efficiency and led to the emergence of larger animals that were able to move. Starting from cup-shaped, gastraea-like animals with outer and inner choanoflagellate-like cells, two major innovations are discussed that set the stage for nervous system evolution. First, the invention of a mucociliary sole entailed a switch from intra- to extracellular digestion and increased the concentration of nutrients flowing into the gastric cavity. In these animals, an initial nerve net may have evolved via division of labour from mechanosensory-contractile cells in the lateral body wall, enabling coordinated movement of the growing body that involved both mucociliary creeping and changes of body shape. Second, the inner surface of the animals folded into metameric series of gastric pouches, which optimized nutrient resorption and allowed larger body sizes. The concomitant acquisition of bilateral symmetry may have allowed more directed locomotion and, with more demanding coordinative tasks, triggered the evolution of specialized nervous subsystems. Animals of this organizational state would have resembled Ediacarian fossils such as Dickinsonia and may have been close to the cnidarian-bilaterian ancestor. In the bilaterian lineage, the mucociliary sole was used mostly for creeping, or frequently lost. One possible remnant is the enigmatic Reissner's fibre in the ventral neural tube of cephalochordates and vertebrates
The Evolutionary Origin of the Runx/CBFbeta Transcription Factors – Studies of the Most Basal Metazoans
BACKGROUND. Members of the Runx family of transcriptional regulators, which bind DNA as heterodimers with CBFβ, are known to play critical roles in embryonic development in many triploblastic animals such as mammals and insects. They are known to regulate basic developmental processes such as cell fate determination and cellular potency in multiple stem-cell types, including the sensory nerve cell progenitors of ganglia in mammals. RESULTS. In this study, we detect and characterize the hitherto unexplored Runx/CBFβ genes of cnidarians and sponges, two basal animal lineages that are well known for their extensive regenerative capacity. Comparative structural modeling indicates that the Runx-CBFβ-DNA complex from most cnidarians and sponges is highly similar to that found in humans, with changes in the residues involved in Runx-CBFβ dimerization in either of the proteins mirrored by compensatory changes in the binding partner. In situ hybridization studies reveal that Nematostella Runx and CBFβ are expressed predominantly in small isolated foci at the base of the ectoderm of the tentacles in adult animals, possibly representing neurons or their progenitors. CONCLUSION. These results reveal that Runx and CBFβ likely functioned together to regulate transcription in the common ancestor of all metazoans, and the structure of the Runx-CBFβ-DNA complex has remained extremely conserved since the human-sponge divergence. The expression data suggest a hypothesis that these genes may have played a role in nerve cell differentiation or maintenance in the common ancestor of cnidarians and bilaterians.National Science Foundation (IBN-0212773, FP-91656101-0); Boston University SPRInG (20-202-8103-9); Israel Science Foundation (825/07
A cell-based model of Nematostella vectensis gastrulation including bottle cell formation, invagination and zippering
AbstractThe gastrulation of Nematostella vectensis, the starlet sea anemone, is morphologically simple yet involves many conserved cell behaviors such as apical constriction, invagination, bottle cell formation, cell migration and zippering found during gastrulation in a wide range of more morphologically complex animals.In this article we study Nematostella gastrulation using a combination of morphometrics and computational modeling. Through this analysis we frame gastrulation as a non-trivial problem, in which two distinct cell domains must change shape to match each other geometrically, while maintaining the integrity of the embryo. Using a detailed cell-based model capable of representing arbitrary cell-shapes such as bottle cells, as well as filopodia, localized adhesion and constriction, we are able to simulate gastrulation and associate emergent macroscopic changes in embryo shape to individual cell behaviors.We have developed a number of testable hypotheses based on the model. First, we hypothesize that the blastomeres need to be stiffer at their apical ends, relative to the rest of the cell perimeter, in order to be able to hold their wedge shape and the dimensions of the blastula, regardless of whether the blastula is sealed or leaky. We also postulate that bottle cells are a consequence of cell strain and low cell–cell adhesion, and can be produced within an epithelium even without apical constriction. Finally, we postulate that apical constriction, filopodia and de-epithelialization are necessary and sufficient for gastrulation based on parameter variation studies
Postpartum Family Planning Service Provision in Durban, South Africa: Client and Provider Perspectives
Researchers in sub-Saharan Africa have found health facility factors influence client contraceptive use. We sought to understand how client provider interactions, discussion of side effects and HIV status influence women’s contraceptive use post-partum. We conducted in-depth interviews with 8 HIV negative clients and 6 HIV positive clients in Zulu and with 5 nurses in English. Interviews were translated and transcribed into English. We created a codebook and coded all transcripts. Nurses and clients reported limited time to discuss contraception, side effects and HIV. Nurses did not comply with national contraceptive policies and created unnecessary barriers to contraceptive use
Fertility Intent and Contraceptive Decision-Making Among HIV Positive and Negative Antenatal Clinic Attendees in Durban, South Africa
We explored contraceptive decision-making among South African antenatal clinic attendees, fertility intent post-HIV diagnosis, and women’s experiences at government health facilities. Data are from in-depth interviews with HIV negative and HIV positive women. We interviewed women in Zulu; interviews were recorded, transcribed and translated. We conducted qualitative analyses of interviews. Women were the dominant decision-makers about contraceptive use, whether they involved their partners or not. A majority of women obtained a contraceptive method at a government facility; however, several women were unable to attain sterilizations. Women were presented with limited contraceptive options and were not always able to access services
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TATTOO-seq delineates spatial and cell type-specific regulatory programs in the developing limb
The coordinated differentiation of progenitor cells into specialized cell types and their spatial organization into distinct domains is central to embryogenesis. Here, we developed and applied an unbiased spatially resolved single-cell transcriptomics method to identify the genetic programs underlying the emergence of specialized cell types during mouse limb development and their spatial integration. We identify multiple transcription factors whose expression patterns are predominantly associated with cell type specification or spatial position, suggesting two parallel yet highly interconnected regulatory systems.We demonstrate that the embryonic limb undergoes a complex multiscale reorganization upon perturbation of one of its spatial organizing centers, including the loss of specific cell populations, alterations of preexisting cell states' molecular identities, and changes in their relative spatial distribution. Our study shows how multidimensional single-cell, spatially resolved molecular atlases can allow the deconvolution of spatial identity and cell fate and reveal the interconnected genetic networks that regulate organogenesis and its reorganization upon genetic alterations
Sexual communication among married couples in the context of a microbicide clinical trial and acceptability study in Pune, India
Previous research in India indicates that there is little communication within marriage about sex. Lack of communication about safe sexual behaviours may increase couples’ vulnerability to HIV. This study explores couple level sexual communication and socio-cultural norms that influence couples’ communication about sex and its implications for HIV prevention. Data derive from in-depth interviews at two points in time with 10 couples. Secondary qualitative analyses of the interviews were conducted using inductive and deductive coding techniques. Half of the couples described improved communication about sex and HIV and AIDS after participation in the clinical trial and/or acceptability study, as well as increased sexual activity, improved relationships by alleviating doubts about their partner’s fidelity and forgiving their partners. The findings show that creating safe spaces for couples where they can ask frank questions about HIV and AIDS, sex and sexuality potentially can improve couples’ communication about sex and reduce their risk for HIV infection
HIV status and postpartum contraceptive use in an antenatal population in Durban, South Africa
We examined contraceptive use and dual protection in the post-partum period in a Prevention of Mother to Child Transmission (PMTCT) population and whether it varied by HIV status
Risk of herpes zoster after exposure to varicella to explore the exogenous boosting hypothesis: self controlled case series study using UK electronic healthcare data.
OBJECTIVE: To assess the magnitude and duration of any hypothesised protective effect of household exposure to a child with varicella on the relative incidence of herpes zoster in adults. DESIGN: Self controlled case series. SETTING: UK general practices contributing to Clinical Practice Research Datalink. PARTICIPANTS: 9604 adults (≥18 years) with a diagnosis of herpes zoster (in primary care or hospital records) between 1997 and 2018, who during their observation period lived with a child (<18 years) with a diagnosis of varicella. MAIN OUTCOME MEASURES: Relative incidence of herpes zoster in the 20 years after exposure to a child with varicella in the household compared with baseline time (all other time, excluding the 60 days before exposure). RESULTS: 6584 of the 9604 adults with herpes zoster (68.6%) were women. Median age of exposure to a child with varicella was 38.3 years (interquartile range 32.3-48.8 years) and median observation period was 14.7 (11.1-17.7) years. 4116 adults developed zoster in the baseline period, 433 in the 60 days before exposure and 5055 in the risk period. After adjustment for age, calendar time, and season, strong evidence suggested that in the two years after household exposure to a child with varicella, adults were 33% less likely to develop zoster (incidence ratio 0.67, 95% confidence interval 0.62 to 0.73) compared with baseline time. In the 10-20 years after exposure, adults were 27% less likely to develop herpes zoster (0.73, 0.62 to 0.87) compared with baseline time. A stronger boosting effect was observed among men than among women after exposure to varicella. CONCLUSIONS: The relative incidence of zoster was lower in the periods after exposure to a household contact with varicella, with modest but long lasting protective effects observed. This study suggests that exogenous boosting provides some protection from the risk of herpes zoster, but not complete immunity, as assumed by previous cost effectiveness estimates of varicella immunisation
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