Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners?

The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h-1 and 20 km ·h-1). VO2 and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg-1· km-1 at 12 km· h-1 and 184.8 ± 9.9 ml· kg-1· km-1 at 20 km· h-1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg-1·km-1 and 0.93 ± 0.07 kcal· kg-1· km-1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h-1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners.

Acyclovir and transmission of HIV-1 from persons infected with HIV-1 and HSV-2.

BACKGROUND: Most persons who are infected with human immunodeficiency virus type 1 (HIV-1) are also infected with herpes simplex virus type 2 (HSV-2), which is frequently reactivated and is associated with increased plasma and genital levels of HIV-1. Therapy to suppress HSV-2 reduces the frequency of reactivation of HSV-2 as well as HIV-1 levels, suggesting that suppression of HSV-2 may reduce the risk of transmission of HIV-1. METHODS: We conducted a randomized, placebo-controlled trial of suppressive therapy for HSV-2 (acyclovir at a dose of 400 mg orally twice daily) in couples in which only one of the partners was seropositive for HIV-1 (CD4 count, > or = 250 cells per cubic millimeter) and that partner was also infected with HSV-2 and was not taking antiretroviral therapy at the time of enrollment. The primary end point was transmission of HIV-1 to the partner who was not initially infected with HIV-1; linkage of transmissions was assessed by means of genetic sequencing of viruses. RESULTS: A total of 3408 couples were enrolled at 14 sites in Africa. Of the partners who were infected with HIV-1, 68% were women, and the baseline median CD4 count was 462 cells per cubic millimeter. Of 132 HIV-1 seroconversions that occurred after randomization (an incidence of 2.7 per 100 person-years), 84 were linked within couples by viral sequencing: 41 in the acyclovir group and 43 in the placebo group (hazard ratio with acyclovir, 0.92, 95% confidence interval [CI], 0.60 to 1.41; P=0.69). Suppression with acyclovir reduced the mean plasma concentration of HIV-1 by 0.25 log(10) copies per milliliter (95% CI, 0.22 to 0.29; P<0.001) and the occurrence of HSV-2-positive genital ulcers by 73% (risk ratio, 0.27; 95% CI, 0.20 to 0.36; P<0.001). A total of 92% of the partners infected with HIV-1 and 84% of the partners not infected with HIV-1 remained in the study for 24 months. The level of adherence to the dispensed study drug was 96%. No serious adverse events related to acyclovir were observed. CONCLUSIONS: Daily acyclovir therapy did not reduce the risk of transmission of HIV-1, despite a reduction in plasma HIV-1 RNA of 0.25 log(10) copies per milliliter and a 73% reduction in the occurrence of genital ulcers due to HSV-2. (ClinicalTrials.gov number, NCT00194519.)

Prevention of vertical transmission of HIV in Khayelitsha, South Africa: A contemporary review of services after 20 years.

BACKGROUND: The first vertical transmission of HIV prevention (VTP) programme in South Africa was launched in 1999 in Khayelitsha, Western Cape Province (WC). Since then, VTP guidelines have expanded in complexity and scope. OBJECTIVES: To describe contemporary VTP uptake in Khayelitsha and quantify vertical transmission (VT) risk factors based on linked routine electronic health data. METHODS: In the WC, all patients at public health facilities have a unique identifier allowing linkage across electronic health platforms through a health information exchange hosted within the WC Department of Health. We conducted a cohort analysis of mother-infant pairs where the mother was living with HIV and attended any obstetric care in Khayelitsha in 2017. Descriptive statistics assessed VTP coverage along the care cascade, including maternal viral load (VL) testing and early infant diagnosis (EID). Logistic regression analysis quantified a priori-defined risk factors associated with VT. RESULTS: Antenatal HIV prevalence in the cohort was 31.3%, and VT was 1.8% by 12 months. Of women living with HIV, 88.3% knew of their positive status at the first antenatal visit and 77.9% were already receiving antiretroviral therapy (ART). Most women diagnosed prior to delivery (94.5%) were initiated on ART; 85.0% received an antenatal VL test, of whom 88.0% were virologically suppressed. Women who were not virally suppressed had a five-fold (adjusted odds ratio (aOR) 5.3; 95% confidence interval (CI) 2.5 - 12.3) increased VT risk compared with those who were suppressed. Women who attended no antenatal care were at higher risk of VT (aOR 1.6; 95% CI 0.7 - 3.6) than those who did attend. EID coverage was suboptimal: a birth HIV polymerase chain reaction (PCR) test was available for 79.2% of infants, and a low proportion with a negative birth test had a repeat test around 10 weeks (57.9%). Data linkage identified an additional 15 infants living with HIV who were not detected by HIV-PCR testing alone. CONCLUSION: Although most women presented to care already knowing their HIV status, ART initiation was suboptimal prior to the first antenatal visit but improved over the course of pregnancy. The VT rate based on laboratory HIV-PCR testing alone underestimated HIV transmission: linked data from multiple sources suggested higher VT than programme-reported rates based on HIV-PCR testing alone.

CD4 T cell depletion at the cervix during HIV infection is associated with accumulation of terminally differentiated T cells.

In blood, the accumulation of terminally differentiated (TD) T cells during HIV infection is associated with CD4 T cell loss and HIV disease progression. Here, we investigated the maintenance and functional characteristics of memory T cells at the cervix. We found that CD4 T cell depletion at the cervix mirrors CD4 depletion in blood. In all women, depletion of CD4 T cells at the cervix was associated with significant reductions in CD45RA- CCR7+ (central memory [CM]) T cells and the accumulation of CD45RA+ CCR7- (TD T cells). We determined whether inflammation in the genital tract was associated with the local differentiation of T cells at the cervix. In uninfected women, genital tract inflammation was associated with the accumulation of CD45RA- CCR7+ CM CD4 T cells and reduced frequencies of CD45RA+ CCR7- TD cells at the cervix. This finding may reflect the fact that, in the absence of HIV infection, TD T cells may be slowly lost in the presence of genital inflammation, while CD45RA- CCR7+ CM T cells are recruited to replenish the diminishing CD4 T cell pool. Following global stimulation with phorbol myristate acetate (PMA)-ionomycin, we noted a significant interleukin 2 (IL-2) deficit in both cervical and blood CD4 T cells from HIV-infected women compared to uninfected women, while gamma interferon (IFN-γ) production was similar, irrespective of HIV status. Few HIV-infected women had detectable IFN-γ and IL-2 HIV-specific T cell responses at the cervix, and these responses were significantly lower in magnitude than the corresponding responses in blood. These data suggest that CD4 depletion was associated with the accumulation of terminally differentiated T cell phenotypes at the cervical mucosa defective in their ability to produce IL-2. CD4 depletion and compromised immunity at the cervix may be accompanied by progressive decline of central memory-like T cells and development of T cells toward terminally differentiated phenotypes.

The relationship between core stability and athletic performance in female university athletes.

Background: Questions remain as to whether core stability represents single or multiple components, how to assess core stability, and if a relationship exists with athletic performance in different sporting codes. Objectives: To investigate the relationship between core stability and athletic performance in female university athletes. Methods: Eighty-three female athletes (hockey, netball, running, soccer and tennis) participated in this quantitative, cross-sectional study. The isometric back extension (IBE), lateral flexion (LF) and abdominal flexion (AF) tests were used to measure core strength and endurance. The core stability grading system using a pressure biofeedback unit was applied to measure core neuromuscular control (NMC). Athletic performance was assessed using the 40 m sprint, T-test, vertical jump (VJ) and the medicine ball chest throw (MBCT). Correlations between the core stability tests and the athletic performance tests were determined overall and separately by sport. The effect of core stability on athletic performance was analysed using ANCOVA. Results: Overall for all sports, most correlations were weak (r=0.10-0.39), although there was a very strong correlation between LF (strength) and VJ (r=0.90). When the sports were considered separately, there were moderate correlations (r=0.40-0.69) between core strength, endurance and motor control with certain athletic performance tests in all five sport codes. In runners, strong correlations (r=0.70-0.89) were observed between AF (endurance) and VJ, and in tennis players between IBE (strength) and the sprint. Conclusion: Correlations were found between core stability and athletic performance, although most correlations were negligible or weak. Athletic performance in different sport codes is associated with different components of core stability.

Performance of FASTPlaqueTB and a modified protocol in a high HIV prevalence community in South Africa.

Modifications in the FASTPlaqueTB test protocol have resulted in an increase in the analytical limits of detection. This study investigated whether the performance of a modified prototype was able to increase the detection of smear-negative, culture-positive sputum samples as compared to the first generation FASTPlaqueTB test. Modifications to the FASTPlaqueTB did result in increased detection of smear-negative samples, but this was associated with a decrease in the specificity of the test. Before the FASTPlaqueTB can be considered as a viable replacement for smear microscopy and culture for the identification of tuberculosis, further work is required to resolve the performance issues identified in this study.

Exploring HIV risk perception and behaviour in the context of antiretroviral treatment: results from a township household survey.

The objective of this cross-sectional household survey was to assess factors influencing HIV risk perception, behaviour and intervention uptake in a community characterised by high HIV prevalence and availability of antiretroviral therapy (ART). The survey was conducted in Khayelitsha, South Africa and involved two-stage sampling with self-weighting clusters and random selection of households within clusters. One man and woman between 14 and 49 years old was interviewed in each household; 696 men and 879 women were interviewed for a response rate of 84% and 92% respectively. Ninety-three percent and 94% were sexually active with median age of sexual debut 15.3 and 16.5 years. Eighty-three percent and 82% reported a partner at the time of interview and 29% and 8% had additional partner(s). Forty-one percent and 33% reported condom use during the last sexual encounter. Thirty-seven percent of men not using condoms did not as they believed their partner to be faithful, whilst 27% of women did not as their partner refused. Twenty-eight percent and 53% had been tested for HIV. Having undergone HIV testing was not associated with condom usage, whilst current relationship status was the strongest association with condom usage for both men and women. In spite of a relatively high uptake of condoms and testing as well as ART availability, the HIV epidemic has continued unabated in Khayelitsha. Even greater coverage of preventive interventions is required, together with a national social and political environment that builds on the availability of both preventive and treatment services.

Mental illness in the Western Cape Province, South Africa: A review of the burden of disease and healthcare interventions.

Neuropsychiatric disorders were ranked third as contributors to disability-adjusted life-years in South Africa (SA). Despite this high morbidity, mental health is often overlooked on the public health agenda. This article reviews evidence on the burden of mental illness in the Western Cape Province of SA, as well as current provincial interventions to decrease the burden of mental illness. Available evidence supports the need for improved integration of mental health services in primary healthcare and strengthening of community services. Challenges include a lack of capacity due to staff shortages and inadequate availability and allocation of resources. Evidence from large epidemiological studies to quantify the burden of disease as well as cost-effectiveness studies of interventions are required to successfully plan and implement interventions. Similar reviews may provide a national overview of mental health issues as well as allow improvement through better understanding of research and best practices in various provinces.

Results of a tuberculosis-specific IFN-gamma assay in children at high risk for tuberculosis infection.

The specificity of the tuberculin skin test (TST) for the diagnosis of latent tuberculosis infection (LTBI) is adversely affected by bacille Calmette-Guérin (BCG) vaccination and infection with non-tuberculous mycobacteria. Interferon-gamma release assays (IGRAs) using TB-specific antigens promise higher specificity. We compared a new IGRA and TST in 184 schoolchildren at high risk for LTBI. The IGRA and TST were positive in 33.2% and 43.5% of the children, respectively (P < 0.001). If studies confirm that this difference is due to higher specificity of this IGRA, it may have an important role to play in the diagnosis of LTBI and identification of children at true risk for TB.

Missed opportunities for immunisation in health facilities in Cape Town, South Africa.

BACKGROUND: Childhood immunisations are a cost-effective public health intervention for prevention of infectious diseases. Immunisation coverage is still suboptimal, however, which may result in disease outbreaks. Immunisation at every contact with a health facility is a strategy developed by the World Health Organization in order to improve immunisation coverage. OBJECTIVES: To estimate the prevalence of missed opportunities for immunisation at different levels of healthcare in the Western Cape Province, South Africa, and assess factors associated with missed opportunities. METHODS: The study included a health facility-based cross-sectional exit survey of caregivers with children up to 5 years of age, followed by a qualitative exploration of staff attitudes towards immunisation. RESULTS: The overall prevalence of missed opportunities for immunisation was 4.6%; 81.3% of caregivers brought Road-to-Health booklets (RTHBs) to consultations; and 56.0% of health workers asked to see the RTHBs during consultations. Children attending primary level facilities were significantly more likely to have their RTHBs requested than children attending a tertiary level facility. Lack of training and resources and heavy workloads were the main challenges reported at secondary/tertiary level facilities. CONCLUSION: Missed opportunities for immunisation at health facilities in Cape Town were low, probably reflecting good immunisation coverage among children accessing health facilities. Increased health worker support, particularly at secondary/tertiary levels of care, is needed to improve the use of RTHBs to provide immunisation.

Isolation of a novel arachidonic acid metabolite 3-hydroxy-5,8,11,14-eicosatetraenoic acid (3-HETE) from the yeast Dipodascopsis uninucleata UOFs-Y128.

When arachidonic acid (AA) is added to the yeast Dipodascopsis uninucleata UOFS Y128, one of the major metabolites isolated and purified with the help of thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) is 3-hydroxy-5,8,11,14-eicosatetraenoic acid (3-HETE). The structure of this new AA metabolite was elucidated mainly by electron impact (EI) mass spectrometry (MS). Strikingly, the formation of this new metabolite was found to be inhibited by aspirin.

The Martin-Bell syndrome in South Africa.

A national screening programme was introduced in 1980 when the first cases with the Martin-Bell syndrome were diagnosed in South Africa. This survey includes patients from all the major population groups in South Africa. One thousand patients, who include 354 relatives of 21 index cases, were investigated cytogenetically. About 75% of the 354 relatives were either affected males or obligate or possible carriers. The segregation pattern of the fragile site was investigated in 271 offspring of 58 carrier women. At least 30% of the carriers were mildly mentally retarded with most expressing the fragile site. Various other investigations, such as measurements of testes, speech, verbal and IQ evaluations and hormone studies were done on several affected males. No fragile site could be demonstrated in 57 unselected autistic children. The results of this programme show that this syndrome is a common cause of mental retardation and that prevention of mental retardation is possible if all the involved families could be identified.

Production of 3R-hydroxy-polyenoic fatty acids by the yeast Dipodascopsis uninucleata.

Various fatty acids were fed to the yeast Dipodascopsis uninucleata UOFS Y 128, and the extracted samples were analyzed for the accumulation of 3-hydroxy metabolites with the help of electron impact gas chromatography-mass spectrometry. Fatty acids containing of 5Z,8Z-diene system (5Z,8Z,11Z-eicosatrienoic, 5Z,8Z,11Z,14Z-eicosatetraenoic, and 5Z,8Z,11Z,14Z,17Z-eicosapentaenoic acids) yielded the corresponding 3-hydroxy-all-Z-eicosapolyenoic acids. Moreover, linoleic acid (9Z,12Z-octadecadienoic acid) and 11Z,14Z,17Z-eicosatrienoic acid were converted to the 3-hydorxylated metabolites of shorter chain length, e,g., 3-hydroxy-5Z,8Z-tetradecadienoic acid and 3-hydroxy-5Z,8Z,11Z-tetradecatrienoic acid, respectively. In contrast, no accumulation of a 3-hydroxy metabolite was observed with oleic acid (9Z-octadecenoic acid), linolelaidic acid (9E,12E-octadecadienoic acid), gamma-linolenic acid (6Z,9Z,12Z-octadecatrienoic acid), and eicosanoic acid as substrate. These findings pinpoint that the 3-hydroxylation of a fatty acid in Dipodascopsis uninucleata requires a 5Z,8Z-diene system either directly or following initial incomplete beta-oxidation. Following analysis of the enantiomer composition, the arachidonic acid metabolite was identified as 3R-hydroxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid, which rules out a normal beta-oxidation as biosynthetic route to this new class of oxylipins.

The effects of cluster sampling in an African urban setting.

Cluster sampling was popularised by the sampling procedure promoted by the WHO/UNICEF for the evaluation of the expanded programme of immunisation (EPI). Without a clear understanding of the limitations of the sampling strategy used, this sampling strategy has been extended to other types of surveys. This article shows how to approach the assessment of cluster sampling techniques scientifically by calculating design effects (DEFFs) and rates of homogeneity (roh) and illustrates this scientific assessment with three case studies from Alexandra in South Africa. We report on the DEFFs and rohs for variables studied in these surveys. The DEFF for all the variables relating to housing tended to exceed two and was as high as 6.99 for the variable new development. The variables relating to health service utilisation and health practices, namely immunisation status, nutrition status, presence of Road to Health Cards (RTDCs), breast-feeding and knowledge of diarrhoea and oral rehydration all had a DEFF close to one. The variables relating to contraception use, literacy and schooling had DEFFs close to one and a half. For a few variables the DEFFs were below one and the rates of homogeneity less than zero. The highest values of roh were for environment factors (all above 0.1433). Rohs for factors related to utilization of PHC services were mostly between 0.0200 and 0.0499. No single class of factors seemed to be related to very low values of roh. These results are then discussed.

The influence of integrated tuberculosis and human immunodeficiency virus service delivery on patient outcomes.

SETTING: Public health clinics in Cape Town, South Africa. OBJECTIVE: To examine the influence of integrated tuberculosis (TB) and human immunodeficiency virus (HIV) service delivery on mortality, TB cure and successful treatment completion and loss to follow-up of TB-HIV co-infected patients on concurrent anti-tuberculosis and antiretroviral treatment (ART). DESIGN: A survey instrument was used to measure the degree to which TB and HIV services were jointly delivered, and patient data were collected retrospectively from clinic sites and the Department of Health. Six domains measuring integrated TB and HIV service delivery were modelled to assess their relationship with patient outcomes. RESULTS: Two domains, integrated TB and ART service delivery and the delivery of TB and HIV care by one clinical team, were associated with lowered odds of death. Care by the same clinical team was also associated with reduced loss to follow-up. CONCLUSION: Overall, these findings show that the organization and delivery of health services are important factors that influence health outcomes. These findings strongly support efforts by local governments to integrate TB and ART services, and may help to alleviate concerns that restructuring of TB programs could have a negative impact on long-standing gains.

Measles vaccination coverage in high-incidence areas of the Western Cape, following the mass vaccination campaign.

BACKGROUND: Despite significant advances in measles control, large epidemics occurred in many African countries in 2009 - 2011, including South Africa. South Africa's control strategy includes mass vaccination campaigns about every 4 years, the last of which was conducted nationally in April 2010 and coincided with the epidemic. AIM: A community survey was conducted in the Western Cape to assess measles vaccination coverage attained by routine and campaign services, in children aged 6 months to 59 months at the time of the mass campaign, from high-incidence areas. METHODS: Households were consecutively sampled in high-incidence areas identified using measles epidemic surveillance data. A caregiver history of campaign vaccination and routine vaccination status from the child's Road to Health card were collected. Pre- and post-campaign immunity was estimated by analytical methods. RESULTS: Of 8 332 households visited, there was no response at 3 435 (41.2%); 95.1% (1 711/1 800) of eligible households participated; and 91.2% (1 448/1 587; 95% confidence interval 86 - 94%) of children received a campaign vaccination. Before the campaign, 33.0% (103/312) of 9 - 17-month-olds had not received a measles vaccination, and this was reduced to 4.5% (14/312) after the campaign. Of the 1 587 children, 61.5% were estimated to have measles immunity before the campaign, and this increased to 94.0% after the campaign. DISCUSSION: Routine services had failed to achieve adequate herd immunity in areas with suspected highly mobile populations. Mass campaigns in such areas in the Western Cape significantly increased coverage. Extra vigilance is required to monitor and sustain adequate coverage in these areas.

From comprehensive medicine to public health at the University of Cape Town: a 40-year journey.

We explore the history of the School of Public Health at the University of Cape Town and its relationship to changes in the understanding of the role of public health both nationally and internationally. We draw from primary and secondary sources to trace the emergence, growth and development of the School, and to situate these processes within the socio-political, clinical and public health contexts in South Africa and internationally.

Use of simulated sputum specimens to estimate the specificity of laboratory-diagnosed tuberculosis.

SETTING: Cross-contamination is not uncommon in mycobacteriology laboratories of high-income countries, as documented by bacterial genotyping. The extent of this problem in low-income countries is largely unknown, where this method is impractical. OBJECTIVE: To estimate the rate of cross-contamination in a high-volume tuberculosis (TB) laboratory in South Africa. DESIGN: Simulated sputum specimens labelled with false names were sent from a TB clinic, interspersed with patient samples, and processed for culture and microscopy. Results were interpreted in the context of the observed proportion of samples with positive microscopy and culture results. RESULTS: With microscopy, 6/190 (3.2%) simulated specimens were positive (estimated specificity = 96.8%). Considering the 881 positive microscopy results in 6093 clinical samples, we extrapolate that 19.3% (95%CI 7.0-42.8) of positive smears were false-positives. On culture, 2/190 (1.1%) of the simulated specimens were positive for Mycobacterium tuberculosis (estimated specificity = 98.9%). Considering the 1862 positive cultures from 6093 clinical samples, we estimate that 2.4% (95%CI 0.3-8.8) of positive cultures were false-positives. CONCLUSION: Simulated specimens offer a simple means of estimating the proportion of false-positive results, providing information on all sources of potential error from the clinic, through the laboratory and to reporting of results.