11 research outputs found

    The Properties of Giant Molecular Clouds in Nearby Galaxies and their Environmental Variation

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    Investigating giant molecular clouds (GMC) in external galaxies presents the opportunity to examine how the distribution, density structure and dynamical state of star forming clouds depend on the galactic environment. This thesis has focused on determining the physical properties and distribution of GMCs and clumps in M33 and compare them to other nearby galaxies including the Milky Way. We have used archival data from the Atacama Millimeter/sub-millimeter Array (ALMA). For the first time, we have resolved and uncovered physical properties of molecular clouds at clump level in M33 at a distance of 840 kpc. We began with resolving NGC 604 GMCs into smaller molecular clouds using 13CO(

    Trends in upper gastrointestinal diagnosis over four decades in Lusaka, Zambia: a retrospective analysis of endoscopic findings

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    BACKGROUND AND AIMS: There a shortage of robust information about profiles of gastrointestinal disease in sub-Saharan Africa. The endoscopy unit of the University Teaching Hospital in Lusaka has been running without interruption since 1977 and this 38-year record is largely intact. We report an analysis of endoscopic findings over this period. METHODS: Written endoscopy records from 29th September 1977 to 16th December 2014 were recovered, computerised, coded by two experienced endoscopists and analysed. Temporal trends were analysed using tables, graphs, and unconditional logistic regression, with age, sex of patient, decade, and endoscopist as independent variables to adjust for inter-observer variation. RESULTS: Sixteen thousand nine hundred fifty-three records were identified and analysed. Diagnosis of gastric ulcer rose by 22 %, and that of duodenal ulcer fell by 14 % per decade. Endoscopically diagnosed oesophageal cancer increased by 32 % per decade, but gastric cancer rose only in patients under 60 years of age (21 % per decade). Oesophageal varices were the commonest finding in patients presenting with haematemesis, increasing by 14 % per decade in that patient group. Two HIV-related diagnoses, oesophageal candidiasis and Kaposi’s sarcoma, rose from almost zero to very high levels in the 1990s but fell substantially after 2005 when anti-retroviral therapy became widely available. CONCLUSIONS: This useful dataset suggests that there are important trends in some endoscopic findings over four decades. These trends are not explained by inter-observer variation. Reasons for the divergent trends in incidence of peptic ulceration and apparent trends in diagnosis of upper gastrointestinal cancers merit further exploration

    Mortality Among HIV-1- and Human Herpesvirus Type 8 – Affected Mother-Infant Pairs in Zambia

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    Objective: To determine the respective trends in mortality of Zambian mother-infant pairs based on maternal infection with HIV-1 and human herpesvirus type 8 (HHV-8). Methods: A prospective cohort study was done on Zambian mother-infant pairs, stratified by maternal serologic status and followed from 6 weeks postdelivery for 48 months. Statistical analysis of the differences in the calculated mortality rates among the four groups was done using Stata 7.0. Kaplan-Meier analysis and Cox proportional hazard models were used to measure subject survival time. Results: Between September 1998 and March 2002, a total of 1,425 mother-infant pairs were enrolled. The crude mortality rate among children born to dually infected mothers was ~9 times higher (245.90 deaths per 1,000 live births) when compared with the death ratio of children born to seronegative mothers (24.63 deaths per 1,000 live births). The incidence rate for death was 0.34/1,000 in infants of co-infected mothers in comparison with 0.32/1,000 among HIV-1-infected mothers, 0.0336/1,000 among uninfected mothers, and 0.0403/1,000 among HHV-8-infected mothers (X2 = 154.56; P \u3c 0.01). Infants of co-infected mothers had a comparable risk of death in comparison with infants infected with HIV-1 alone {hazard ratio, 9.91 [95% confidence interval (95% Cl), 5.08-19.37] for co-infected versus 9.26 [95% CI, 4.75-18.07] for HIVI- infected alone}. Infants of mothers infected only with HHV-8 also had comparable survival in comparison with uninfected infants (hazard ratio, 1.21; 95% CI, 0.56-2.61). Conclusion: Infants born to mothers dually infected with both HIV-1 and HHV-8 have comparable survival with infants exposed to HIV-1 alone. Infants born to mothers infected only with HHV-8 have comparable survival with uninfected infants

    Postnatal Human Herpesvirus 8 and Human Immunodeficiency Virus Type 1 Infection in Mothers and Infants from Zambia

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    The specific route and timing of human herpesvirus (HHV) 8 infection in regions where Kaposi sarcoma is endemic are not known. HHV-8 infection and any risk factors that may be associated with HHV-8, including human immunodeficiency virus (HIV) type 1 infection, were monitored during the 12-month post-delivery period for 416 mothers and 485 infants from Lusaka, Zambia. HHV-8 incident infection rates during this period were 3.2 and 5.3 infections/100 person-years for infants and mothers, respectively. HHV-8 infection among infants was not associated with HHV-8 or HIV-1 infection in the mother. Among the HHV-8–positive infants, 2 of 12 tested were found to have HHV-8 DNA in their peripheral blood mononuclear cells at birth, which suggests that in utero infection is possible. However, most HHV-8–positive infants appeared to have acquired infection either intrapartum or postpartum. The present study indicates that transmission of HHV- 8 to infants can occur early and is likely via multiple routes

    Development of an Immunofluorescence Assay Using Recombinant Proteins Expressed in Insect Cells To Screen and Confirm Presence of Human Herpesvirus 8-Specific Antibodiesâ–ż

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    Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma (KS)-associated herpesvirus, has been linked to all forms of KS. The results of most current serological assays for the detection of HHV-8-specific antibodies have low levels of concordance among themselves. To establish a sensitive and specific testing strategy that can be used to screen for HHV-8-specific antibodies, three HHV-8 proteins, ORF65, ORF73, and K8.1A, were expressed by using baculoviral vectors in insect cells and incorporated into a monoclonal antibody-enhanced immunofluorescence assay (mIFA) termed the Sf9 three-antigen mIFA. The results obtained by this mIFA were compared to those obtained by a standard mIFA with an HHV-8-infected B-cell line (BC3 mIFA). Test sera were obtained from patients diagnosed with KS, human immunodeficiency virus type 1-infected patients at high risk for HHV-8 infection, and healthy controls from a local blood bank. The combined use of both assays had a sensitivity of 94% and a specificity of 96%. The performance of these two assays when they were used together indicates that they may be useful for the reliable detection of HHV-8-specific immunoglobulin G antibodies in a population
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