118 research outputs found

    The prevention of mother-to-child HIV transmission programme and infant feeding practices

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    Tuberculosis in HIV-infected South African children with complicated severe acute malnutrition.

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    Academic tertiary referral hospital in Durban, South Africa. To describe the incidence and diagnostic challenges of tuberculosis (TB) in human immunodeficiency virus (HIV) infected children with severe acute malnutrition (SAM). Post-hoc analysis of a randomised controlled trial that enrolled antiretroviral therapy naïve, HIV-infected children with SAM. Trial records and hospital laboratory results were explored for clinical diagnoses and bacteriologically confirmed cases of TB. Negative binomial regression was used to explore associations with confirmed cases of TB, excluding cases where the clinical diagnosis was not supported by microbiological confirmation. Of 82 children enrolled in the study, 21 (25.6%) were diagnosed with TB, with bacteriological confirmation in 8 cases. Sputum sampling (as opposed to gastric washings) was associated with an increased risk of subsequent diagnosis of TB (adjusted relative risk [aRR] 1.134, 95%CI 1.02-1.26). Culture-proven bacterial infection during admission was associated with a reduced risk of TB (aRR 0.856, 95%CI 0.748-0.979), which may reflect false-negative microbiological tests secondary to empiric broad-spectrum antibiotics. TB is common in HIV-infected children with SAM. While microbiological confirmation of the diagnosis is feasible, empiric treatment remains common, possibly influenced by suboptimal testing and false-negative TB diagnostics. Rigorous microbiological TB investigation should be integrated into the programmatic management of HIV and SAM

    HIV-Associated Tuberculosis in the Newborn and Young Infant

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    Each year, approximately 250 000 women die during pregnancy, delivery, or postpartum. Maternal mortality rates due to tuberculosis (TB) and HIV in Sub-Saharan Africa now supersede obstetric-related causes of mortality. The majority of cases occur in population-dense regions of Africa and Asia where TB is endemic. The vertical transmission rate of tuberculosis is 15%, the overall vertical transmission rate of HIV in resource-limited settings with mono- or dual-ARV therapy varies from 1.9% to 10.7%. If the millennium development goals are to be achieved, both HIV and TB must be prevented. The essential aspect of TB prevention and detection in the newborn is the maternal history and a positive HIV status in the mother. Perinatal outcomes are guarded even with treatment of both diseases. Exclusive breast feeding is recommended. The community and social impact are crippling. The social issues aggravate the prognosis of these two diseases

    Mice Deficient in T-bet Form Inducible NO Synthase-Positive Granulomas That Fail to Constrain Salmonella.

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    Clearance of intracellular infections caused by Salmonella Typhimurium (STm) requires IFN-γ and the Th1-associated transcription factor T-bet. Nevertheless, whereas IFN-γ-/- mice succumb rapidly to STm infections, T-bet-/- mice do not. In this study, we assess the anatomy of immune responses and the relationship with bacterial localization in the spleens and livers of STm-infected IFN-γ-/- and T-bet-/- mice. In IFN-γ-/- mice, there is deficient granuloma formation and inducible NO synthase (iNOS) induction, increased dissemination of bacteria throughout the organs, and rapid death. The provision of a source of IFN-γ reverses this, coincident with subsequent granuloma formation and substantially extends survival when compared with mice deficient in all sources of IFN-γ. T-bet-/- mice induce significant levels of IFN-γ- after challenge. Moreover, T-bet-/- mice have augmented IL-17 and neutrophil numbers, and neutralizing IL-17 reduces the neutrophilia but does not affect numbers of bacteria detected. Surprisingly, T-bet-/- mice exhibit surprisingly wild-type-like immune cell organization postinfection, including extensive iNOS+ granuloma formation. In wild-type mice, most bacteria are within iNOS+ granulomas, but in T-bet-/- mice, most bacteria are outside these sites. Therefore, Th1 cells act to restrict bacteria within IFN-γ-dependent iNOS+ granulomas and prevent dissemination

    Resolving Salmonella infection reveals dynamic and persisting changes in murine bone marrow progenitor cell phenotype and function

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    The generation of immune cells from BM precursors is a carefully regulated process. This is essential to limit the potential for oncogenesis and autoimmunity yet protect against infection. How infection modulates this is unclear. Salmonella can colonize systemic sites including the BM and spleen. This resolving infection has multiple IFN-γ-mediated acute and chronic effects on BM progenitors, and during the first week of infection IFN-γ is produced by myeloid, NK, NKT, CD4+ T cells, and some lineage-negative cells. After infection, the phenotype of BM progenitors rapidly but reversibly alters, with a peak ∼30-fold increase in Sca-1hi progenitors and a corresponding loss of Sca-1lo/int subsets. Most strikingly, the capacity of donor Sca-1hi cells to reconstitute an irradiated host is reduced; the longer donor mice are exposed to infection, and Sca-1hic-kitint cells have an increased potential to generate B1a-like cells. Thus, Salmonella can have a prolonged influence on BM progenitor functionality not directly related to bacterial persistence. These results reflect changes observed in leucopoiesis during aging and suggest that BM functionality can be modulated by life-long, periodic exposure to infection. Better understanding of this process could offer novel therapeutic opportunities to modulate BM functionality and promote healthy aging

    Survival of Infants Born to HIV-Positive Mothers, by Feeding Modality, in Rakai, Uganda

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    Data comparing survival of formula-fed to breast-fed infants in programmatic settings are limited. We compared mortality and HIV-free of breast and formula-fed infants born to HIV-positive mothers in a program in rural, Rakai District Uganda.One hundred eighty two infants born to HIV-positive mothers were followed at one, six and twelve months postpartum. Mothers were given infant-feeding counseling and allowed to make informed choices as to whether to formula-feed or breast-feed. Eligible mothers and infants received antiretroviral therapy (ART) if indicated. Mothers and their newborns received prophylaxis for prevention of mother-to-child HIV transmission (pMTCT) if they were not receiving ART. Infant HIV infection was detected by PCR (Roche Amplicor 1.5) during the follow-up visits. Kaplan Meier time-to-event methods were used to compare mortality and HIV-free survival. The adjusted hazard ratio (Adjusted HR) of infant HIV-free survival was estimated by Cox regression. Seventy-five infants (41%) were formula-fed while 107 (59%) were breast-fed. Exclusive breast-feeding was practiced by only 25% of breast-feeding women at one month postpartum. The cumulative 12-month probability of infant mortality was 18% (95% CI = 11%–29%) among the formula-fed compared to 3% (95% CI = 1%–9%) among the breast-fed infants (unadjusted hazard ratio (HR)  = 6.1(95% CI = 1.7–21.4, P-value<0.01). There were no statistically significant differentials in HIV-free survival by feeding choice (86% in the formula-fed compared to 96% in breast-fed group (Adjusted RH = 2.8[95%CI = 0.67–11.7, P-value = 0.16]Formula-feeding was associated with a higher risk of infant mortality than breastfeeding in this rural population. Our findings suggest that formula-feeding should be discouraged in similar African settings

    Adult liver transplantation in Johannesburg South Africa 2004 2016: Balancing good outcomes constrained resources and limited donors

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    Background. Liver transplantation is the standard of care for the treatment of liver failure worldwide, yet millions of people living in sub-Saharan Africa remain without access to these services. South Africa (SA) has two liver transplant centres, one in Cape Town and the other in Johannesburg, where Wits Donald Gordon Medical Centre (WDGMC) started an adult liver transplant programme in 2004.Objectives. To describe the outcomes of the adult liver transplant programme at WDGMC.Methods. This was a retrospective review of all adult orthotopic liver transplants performed at WDGMC from 16 August 2004 to 30 June 2016 with a minimum follow-up of 6 months. The primary outcome was recipient and graft survival and the effect of covariates on survival. Kaplan-Meier survival analysis included all adults who underwent their first transplant for end-stage liver disease (ESLD) (N=275). Proportional hazards regression analysis using hazard ratios (HRs) was conducted to determine which covariates were associated with a significantly increased risk of mortality.Results. A total of 297 deceased-donor liver transplants were performed during the study period; 19/297 (6.4%) were for acute liver failure (ALF) and the remainder were for ESLD. The median age of recipients was 51 years (interquartile range 41 - 59), and two-thirds were male. The most common cause of ESLD was primary sclerosing cholangitis. The median follow-up was 3.2 years, and recipient survival was characterised in the following intervals: 90 days = 87.6% (95% confidence interval (CI) 83.1 - 91.0), 1 year = 81.7% (95% CI 76.6 - 85.8), and 5 years = 71.0% (95% CI 64.5 - 76.5). Allograft survival was similar: 90 days = 85.8% (95% CI 81.1 - 89.4), 1 year = 81.0% (95% CI 75.8 - 85.2), and 5 years = 69.1% (95% CI 62.6 - 74.7). The most significant covariates that impacted on mortality were postoperative biliary leaks (HR 2.0 (95% CI 1.05 - 3.80)), recipient age &gt;60 years at time of transplant (HR 2.06 (95% CI 1.06 - 3.99)), theatre time &gt;8  hours (HR 3.13 (95% CI 1.79 - 5.48)), and hepatic artery thrombosis (HR 5.58 (95% CI 3.09 - 10.08)). The most common infectious cause of death was invasive fungal infection.Conclusions. This study demonstrates that outcomes of the adult orthotopic liver transplant programme at WDGMC are comparable with international transplant centres. Management of biliary complications, early hepatic artery thrombosis and post-transplant infections needs to be improved. Access to liver transplantation services is still extremely limited, but can be improved by addressing the national shortage of deceased donors and establishing a national regulatory body for solid-organ transplantation in SA.Â

    Inflammation drives thrombosis after Salmonella infection via CLEC-2 on platelets

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    Thrombosis is a common, life-threatening consequence of systemic infection; however, the underlying mechanisms that drive the formation of infection-associated thrombi are poorly understood. Here, using a mouse model of systemic Salmonella Typhimurium infection, we determined that inflammation in tissues triggers thrombosis within vessels via ligation of C-type lectin-like receptor-2 (CLEC-2) on platelets by podoplanin exposed to the vasculature following breaching of the vessel wall. During infection, mice developed thrombi that persisted for weeks within the liver. Bacteria triggered but did not maintain this process, as thrombosis peaked at times when bacteremia was absent and bacteria in tissues were reduced by more than 90% from their peak levels. Thrombus development was triggered by an innate, TLR4-dependent inflammatory cascade that was independent of classical glycoprotein VI-mediated (GPVI-mediated) platelet activation. After infection, IFN-ã release enhanced the number of podoplanin-expressing monocytes and Kupffer cells in the hepatic parenchyma and perivascular sites and absence of TLR4, IFN-ã, or depletion of monocytic-lineage cells or CLEC-2 on platelets markedly inhibited the process. Together, our data indicate that infection-driven thrombosis follows local inflammation and upregulation of podoplanin and platelet activation. The identification of this pathway offers potential therapeutic opportunities to control the devastating consequences of infection-driven thrombosis without increasing the risk of bleeding

    Adult liver transplantation in Johannesburg, South Africa (2004 - 2016): Balancing good outcomes, constrained resources and limited donors

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    Background. Liver transplantation is the standard of care for the treatment of liver failure worldwide, yet millions of people living in sub-Saharan Africa remain without access to these services. South Africa (SA) has two liver transplant centres, one in Cape Town and the other in Johannesburg, where Wits Donald Gordon Medical Centre (WDGMC) started an adult liver transplant programme in 2004.Objectives. To describe the outcomes of the adult liver transplant programme at WDGMC.Methods. This was a retrospective review of all adult orthotopic liver transplants performed at WDGMC from 16 August 2004 to 30 June 2016 with a minimum follow-up of 6 months. The primary outcome was recipient and graft survival and the effect of covariates on survival. Kaplan-Meier survival analysis included all adults who underwent their first transplant for end-stage liver disease (ESLD) (N=275). Proportional hazards regression analysis using hazard ratios (HRs) was conducted to determine which covariates were associated with a significantly increased risk of mortality.Results. A total of 297 deceased-donor liver transplants were performed during the study period; 19/297 (6.4%) were for acute liver failure (ALF) and the remainder were for ESLD. The median age of recipients was 51 years (interquartile range 41 - 59), and two-thirds were male. The most common cause of ESLD was primary sclerosing cholangitis. The median follow-up was 3.2 years, and recipient survival was characterised in the following intervals: 90 days = 87.6% (95% confidence interval (CI) 83.1 - 91.0), 1 year = 81.7% (95% CI 76.6 - 85.8), and 5 years = 71.0% (95% CI 64.5 - 76.5). Allograft survival was similar: 90 days = 85.8% (95% CI 81.1 - 89.4), 1 year = 81.0% (95% CI 75.8 - 85.2), and 5 years = 69.1% (95% CI 62.6 - 74.7). The most significant covariates that impacted on mortality were postoperative biliary leaks (HR 2.0 (95% CI 1.05 - 3.80)), recipient age &gt;60 years at time of transplant (HR 2.06 (95% CI 1.06 - 3.99)), theatre time &gt;8  hours (HR 3.13 (95% CI 1.79 - 5.48)), and hepatic artery thrombosis (HR 5.58 (95% CI 3.09 - 10.08)). The most common infectious cause of death was invasive fungal infection.Conclusions. This study demonstrates that outcomes of the adult orthotopic liver transplant programme at WDGMC are comparable with international transplant centres. Management of biliary complications, early hepatic artery thrombosis and post-transplant infections needs to be improved. Access to liver transplantation services is still extremely limited, but can be improved by addressing the national shortage of deceased donors and establishing a national regulatory body for solid-organ transplantation in SA.
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