Lactic acidosis, risk factors and predictive laboratory markers: a nested case control study in South Africa

Background: The incidence of antiretroviral therapy (ART)-induced lactic acidosis and its associated mortality may be reduced by appropriate  dosing, risk stratification and early detection.Objectives: To describe the epidemiology of lactic acidosis, define the risk factors and identify predictive laboratory markers in the context of the roll-out of ART in South Africa.Design: A nested case control study. Risk factor analysis was adjusted for the established risk factors of weight and gender.Setting and subjects: Persons commenced on stavudine-containing  therapy between 2004 and 2007 at Port Shepstone Hospital in  KwaZulu-Natal were included. Persons with a body weight above 60 kg received Stavudine 40 mg twice daily, and those with a body weight below 60 kg, 30 mg twice daily.Outcome measures: Assessed risk factors included weight, gender, age, alanine transaminase (ALT), urea, creatinine, albumin, cholesterol, triglyceride (TG) levels, CD4 counts and viral loads.Results: Lactic acidosis occurred in 79 (17 per 1 000 person-years) of 1 762 people living with HIV on ART. Significant factors were being female [adjusted odds ratio (AOR) of 5.4] and increased body weight (adjusted OR of 1.1 per kg). The risk of lactic acidosis increased 6.6, 6.9 and 95 times (adjusted ORs) as weight increased from a baseline weight of < 60 kg to 60-69 kg, 70-79 kg or > 80 kg, respectively. Six months into therapy, predictors of developing lactic acidosis were an ALT > 50 IU/l (adjusted OR of 11.1) and a higher TG (adjusted OR of 8.8 per mmol/l). No associations were found with regard to age, CD4 count, viral load, and creatinine or albumin levels.Conclusion: Obese females are at greatest risk of lactic acidosis, with an exponential increase in risk above 80 kg. The 30-mg dose may be preferable, given that a sharp increase in risk occurred at 60 kg, was most likely dose related, and that 30 mg has been shown to provide adequate virological suppression. Additional risk factors for lactic acidosis include a high ALT and TG levels at treatment

Risky sexual behaviours of high-school pupils in an era of HIV and AIDS

Objective. To identify risky sexual behaviours and demographic factors that place high-school pupils at risk of HIV and AIDS. Methods. A cross-sectional study was undertaken to explore factors influencing the sexual behaviour of high-school pupils (mean age 15.4 years; SD 1.11). Structured self-reported questionnaires were completed by all grade 10 pupils (N=805) at all the Wentworth, Durban, public high schools. Results. Significant gender differences in sexual practices were reported, such as males being more likely to engage in sexual activity than females (OR 4.92;

ExoMars Schiaparelli Direct-to-Earth Observation using GMRT

During the ExoMars Schiaparelli separation event on 16 October 2016 and Entry, Descent, and Landing (EDL) events 3 days later, the Giant Metrewave Radio Telescope (GMRT) near Pune, India, was used to directly observe UHF transmissions from the Schiaparelli lander as they arrive at Earth. The Doppler shift of the carrier frequency was measured and used as a diagnostic to identify key events during EDL. This signal detection at GMRT was the only real‐time aliveness indicator to European Space Agency mission operations during the critical EDL stage of the mission

ExoMars Schiaparelli Direct-to-Earth Observation using GMRT

During the ExoMars Schiaparelli separation event on 16 October 2016 and Entry, Descent, and Landing (EDL) events 3 days later, the Giant Metrewave Radio Telescope (GMRT) near Pune, India, was used to directly observe UHF transmissions from the Schiaparelli lander as they arrive at Earth. The Doppler shift of the carrier frequency was measured and used as a diagnostic to identify key events during EDL. This signal detection at GMRT was the only real‐time aliveness indicator to European Space Agency mission operations during the critical EDL stage of the mission

Investigating the association between diabetes mellitus, depression and psychological distress in a cohort of South African teachers

Background. Diabetes mellitus (DM) may increase the risk of depression as a result of a sense of threat of debilitating complications or because of associated lifestyle changes. Depression may increase the risk of type 2 diabetes as a result of poor health behaviours.Objective. To determine the association between diabetes mellitus, depression and psychological  distress in a cohort of South African (SA) teachers.Methods. Teachers from 111 public schools in the Metro South District of the Cape Metropolitan area,  SA, were invited to participate in this study. The Center for Epidemiologic Studies Depression Scale  (CES-D) and the Kessler Psychological Distress Scale (K10) were used to assess depression and psychological distress, respectively. A professional nurse completed a physical examination and  collected blood for measurement of glucose, cholesterol and serum creatinine.Results. Of the 388 teachers who completed the questionnaires, 67.5% were female and the average age  was 46.2 years (standard deviation 8.7). Psychological distress was identified in 28.1% of the cohort and depression in 15.5%, and 7.7% were found to fulfil criteria for DM. A diagnosis of DM was associated with an increased risk of depression (adjusted odds ratio (AOR) 3.90; 95% confidence interval (CI) 1.33 - 11.37) and psychological distress (AOR 3.62; 95% CI 1.31 - 10.00).Conclusion. The high prevalence of obesity and DM in this cohort of SA teachers is of concern. A  diagnosis of DM was strongly associated with an increased risk of depression and psychological distress

Model Predictive Control Tailored to Epidemic Models

We propose a model predictive control (MPC) approach for minimising the social distancing and quarantine measures during a pandemic while maintaining a hard infection cap. To this end, we study the admissible and the maximal robust positively invariant set (MRPI) of the standard SEIR compartmental model with control inputs. Exploiting the fact that in the MRPI all restrictions can be lifted without violating the infection cap, we choose a suitable subset of the MRPI to define terminal constraints in our MPC routine and show that the number of infected people decays exponentially within this set. Furthermore, under mild assumptions we prove existence of a uniform bound on the time required to reach this terminal region (without violating the infection cap) starting in the admissible set. The findings are substantiated based on a numerical case study.Comment: 14 pages, 3 figure

Enchytraeus crypticus Avoid Soil Spiked with Microplastic.

Microplastics (MPs) of varying sizes are widespread pollutants in our environment. The general opinion is that the smaller the size, the more dangerous the MPs are due to enhanced uptake possibilities. It would be of considerably ecological significance to understand the response of biota to microplastic contamination both physically and physiologically. Here, we report on an area choice experiment (avoidance test) using Enchytraeus crypticus, in which we mixed different amounts of high-density polyethylene microplastic particles into the soil. In all experimental scenarios, more Enchytraeids moved to the unspiked sections or chose a lower MP-concentration. Worms in contact with MP exhibited an enhanced oxidative stress status, measured as the induced activity of the antioxidative enzymes catalase and glutathione S-transferase. As plastic polymers per se are nontoxic, the exposure time employed was too short for chemicals to leach from the microplastic, and as the microplastic particles used in these experiments were too large (4 mm) to be consumed by the Enchytraeids, the likely cause for the avoidance and oxidative stress could be linked to altered soil properties

Dual and triple therapy to prevent mother-to-child transmission of HIV in a resource-limited setting – lessons from a South African programme

Objective. To determine outcomes of pregnant women and their infants at McCord Hospital in Durban, South Africa, where dual and triple therapy to reduce HIV vertical transmission have been used since 2004 despite national guidelines recommending simpler regimens. Method. We retrospectively examined records of all pregnant women attending McCord Hospital for their first antenatal visit between 1 March 2004 and 28 February 2007. Uptake of HIV testing and HIV prevalence were determined, and clinical, immunological and virological outcomes of HIV-positive women and their infants, followed through to 6 months after delivery, were described. Results. The antenatal clinic was attended by 5 303 women; 4 891 (92%) had an HIV test, and 703 (14%) were HIV positive. The HIV-positive women were subsequently followed up: 653 (93%) received antiretroviral therapy or prophylaxis, including 424 (60%) who received triple therapy. Of the 699 live babies delivered, 661 (94%) received prophylaxis. At 6 weeks 571 babies (82%) were brought back for HIV testing; 16 (2.8%) were HIV positive. After 6 months, only 150 women (21%) were receiving follow-up care at the adult HIV clinic. Conclusion. Where a tailored approach to prevention of motherto-child transmission (PMTCT) is used, which attempts to maximise available technology and resources, good short-term transmission outcomes can be achieved. However, longer-term follow-up of mothers’ and babies’ health presents a challenge. Successful strategies to link women to ongoing care are crucial to sustain the gains of PMTCT programmes