PROFICIENCY AT OBJECT CONTROL SKILLS BY NINE- TO TEN-YEAR-OLD CHILDREN IN SOUTH AFRICA: THE NW-CHILD STUDY.

Adequate proficiency at object control skills, which is influenced by biological and environmental constraints, underlies the development of more complex sport-specific skills. This study describes proficiency at six object control skills and demographic correlates associated with each skill and each skill criteria in 9- to 10-year-old children who were randomly selected from 20 schools (N=826) and tested with the Test of Gross Motor Development-2. Cross-tabulation and hierarchical linear models were used to analyze the effects of sex (433 boys, 393 girls), ethnicity (619 Black, 207 White), and high (n=312) and low (n= 514) socioeconomic school environments. Twenty-three percent of the sample showed below average proficiency. Significant sex and socioeconomic school environment differences were found favoring boys and children from higher socioeconomic environments, although kicking showed significant interaction effects. It is concluded that environmental opportunities are the primary cause of differences across skills and the rates at which the skills are learned.

2-Methoxyestradiol-bis-sulfamate induces apoptosis and autophagy in a tumorigenic breast epithelial cell line.

In anticancer research where the focus is on finding agents that induces cell death while leaving non-tumorigenic cells less affected, a novel 2-methoxyestradiol derivative has come forth. 2-Methoxyestradiol-bis-sulfamate (2-MeOE2bisMATE) is a 2-methoxyestradiol derivative produced by bis-sulphamoylation, which possesses increased antiproliferative activity and biological availability. Several questions remain regarding the type of cell death mechanisms and possible induction of autophagy by 2-MeOE2bisMATE. The aim of this in vitro study was to investigate the cell death mechanisms exerted by 2-MeOE2bisMATE in an adenocarcinoma cell line (MCF-7) by analyzing its influence on cell growth, morphology, and possible induction of cell death. Spectrophotometry (crystal violet staining), transmission electron microscopy (TEM), light microscopy (hematoxylin and eosin staining), and fluorescent microscopy (Hoechst 33342, propidium iodide and acridine orange) were employed. Spectrophotometrical studies indicated that 2-MeOE2bisMATE decreased cell numbers to 75% in MCF-7 cells after 24 h and to 47% after 48 h of exposure. TEM demonstrated membrane blebbing, nuclear fragmentation, and chromatin condensation indicating the hallmarks of apoptosis. Light microscopy revealed the presence of several cells blocked in metaphase, and apoptotic cells were also observed. Fluorescent microscopy demonstrated increased lysosomal staining; suggesting the induction of autophagy. 2-MeOE2bisMATE shows therapeutic potential, as an, anticancer agent, and the investigation of the cell death mechanisms used by 2-MeOE2bisMATE, thus, warrants further investigation.

Allelic frequencies of host genetic variants influencing susceptibility to HIV-1 infection and disease in South African populations.

OBJECTIVES: Limited information is available on the prevalence in African populations of host genetic polymorphisms conferring resistance to HIV-1 infection and disease. The objective of this study was to determine the allelic frequencies in South African populations of the chemokine receptor gene variants CCR5delta32, CCR5m303 and CCR2b-641 and the CXCR4 ligand gene variant SDF1-3'A. METHOD: Cross-sectional study to determine the prevalence of these gene variants in South African subjects of African and European descent. RESULTS: The CCR5delta32 genetic variant is rare in individuals of African origin, having an allelic frequency of 0.1% (n = 1247) compared with 9.8% (n = 144) in Caucasians. The CCR5m303 mutation was not detected in Africans (n = 687), whereas an allelic frequency of 0.9% (n = 145) was identified in Caucasians. The frequency of CCR2b-641 allele was 13.1% (n = 180) in Africans, which was significantly higher that the 7.2% (n = 146) detected in Caucasians. Finally the allelic frequency of the SDF1-3'A gene variant was only 1.0% (n = 198) in Africans compared with 19.8% (n = 145) in Caucasians. CONCLUSIONS: These results indicate that genetic polymorphisms conferring resistance to HIV-1 infection are rare in the South African Black population. Except for the CCR2b-641 gene variant, individuals of African origin also had a much lower prevalence of genetic variants associated with prolonged disease progression.

Serum ferritin concentrations in black miners.

Serum ferritin concentrations were measured in 651 Black male miners who originated from rural areas throughout southern Africa and who were aged between 17 and 57 years. The mean serum ferritin concentration of 229 microgram/l was above the normal range reported for White subjects, and in 52,8% of the subjects the values were greater than 200 microgram/l. The serum ferritin concentration rose with age, as did the proportion of subjects in each age group who exhibited high values (more than 200 microgram/l). The lowest mean ferritin concentration (112 microgram/l) as well as the lowest proportion of high values (22,9%) were found in subjects from the most northerly area studied. Similarly, the highest mean proportion of high values (66,3%) was seen in the most southerly group studied. Calculations from the present data suggest that the degree of iron overload is currently greater in rural than in urban Black male subjects.

The genesis of amniotic fluid infections.

Amniotic fluid infections manifested by an inflammatory response in the extraplacental membranes and subchorionic plate of the placenta are a common phenomenon thought to be due in most cases to ascending bacterial infections via intact membranes. Fatal spread to the fetus is much less common and more likely to occur in underprivileged communities. The probable reasons are nutritional deprivation in the mother or both, leading to production of a liquor with diminished ability to suppress bacterial growth. Zinc is one component of the antibacterial system but liquor levels of zinc vary widely and inconsistently with antibacterial activity. Dietary supplementation with zinc did not improve antibacterial activity of liquors in a population with diminished liquor antibacterial activity and large number of fatal infections. Other factors in the genesis of amniotic fluid infections may be interference with normal defence mechanisms as a result of coitus in late pregnancy and vaginal infections with Trichomonas vaginalis. Socioeconomic factors may play a role apart from their association with maternal nutrition, through diminished hygiene associated with insufficient use of water and insufficient availability and use of medical facilities.

Effect of vitamin C supplementation on black mineworkers.

Subclinical vitamin C deficiency frequently occurs in Black mineworkers, in spite of an apparently adequate daily intake. A study was undertaken to establish the minimum rate of supplementation that would effectively reduce the incidence of subclinical vitamin C deficiency. Two levels of supplementation were tested in relation to a control group. It was found that a supplementation rate of at least 235 mg/head/day is required to maintain reasonably adequate serum levels. It was also found that effective control measures are required to ensure that the supplement is added to the magou, the staple beverage of the miners. It is strongly recommended that the intake of every Black mineworker be supplemented at a rate of 200 - 250 mg/day.

Biochemical aspects of a study of 100 obese white subjects.

The effect of a 7 100 kilojoule diet (50% of the energy derived from carbohydrate, mainly unrefined, 30% from fat, mainly unsaturated, and 20% from protein) on 100 overweight subjects was investigated. It was found that 45% of subjects did not complete the study, 9% continued with the study but did not lose weight, 25% lost weight moderately well and 21% responded very well and lost a mean of 15,9 kg over a 6-9 month period. Very little indication of water retention was found. The following biochemical changes occurred during the study period: 1. There was a marked improvement in the glucose tolerance of the groups that lost weight effectively. 2. This improvement in glucose tolerance was associated with a very marked decrease in the secretion of immuno-reactive insulin. 3. The tendency for serum cholesterol and triglyceride levels to decrease during the study was also evidenced in the changes which occurred in the lipoprotein electrophoresis patterns. Stepwise discriminant analysis performed on biochemical, clinical and psychological data failed to provide a practical means of discriminating in advance between the likely response of subjects to this dietary therapy with acceptable accuracy.