HIV modelling in a labour force

A section of the workforce employed by a certain company has been found to be HIV positive. Demographic, social and clinical data has been gathered by medical practitioners at the company's Wellness Centre for each patient from the time they were put in a wellness programme to monitor their health and fitness for placement in various work categories with different levels of labour intensity. The medical staff would like to know how the collected data can be used to determine critical indicators that a given patient is fit to go back to work in the same job, and for how long he can stay on that job. CART analysis software is used to investigate the problem. Among the variables in the data, mass and viral load are found to rank high in importance as determinants for making a decision on the fitness of the participants

Mountain bike racing - the influence of prior glycogen-inducing exercise and glutamine supplementation on selected stress and immune parameters

Objective. To investigate the effect of pre-exercise glutamine supplementation and the influence of a prior acute bout of glycogen-reducing exercise on the general stress and immune response to acute high-intensity cycling. Design. Randomised, double-blind, cross-over supplementation study. Setting and intervention. Subjects performed a series of 4 simulated mountain-bike races lasting &#8776;60 minutes each on separate days 1 week apart, with/ without prior glycogen- reducing exercise on a known outdoor course with/ without pre-exercise glutamine supplementation. Blood samples were collected pre- and immediately post-exercise after each race. Main outcome measures. Circulating concentrations of cortisol (COR) and dehydroepiandrosterone-sulphate (DHEAS) were assessed at all time points, as well as changes in white blood cell (WBC) subpopulation distribution. Results. COR was elevated in all groups post-exercise (p < 0.0001), but neither glycogen reduction, nor glutamine supplementation had any effect. DHEAs increased post-exercise (p < 0.05), with a greater relative increase in glutamine-supplemented subjects (p = 0.07). Total WBC and neutrophil counts in all groups were elevated after exercise (both p < 0.0005). Glutamine supplementation had no effect on differential WBC counts or distribution, but total WBC (p = 0.06) and monocyte (p < 0.05) counts showed greater increases after glycogen reduction. Gluta- mine supplementation was associated with greater postexercise decreases in CD4+ count (p = 0.07) and CD4+: CD8+ ratio (p = 0.01) after glycogen-reducing exercise. Conclusions. We conclude that pre-exercise glutamine supplementation may have an anticortisol effect by enhancing the DHEAS response to exercise stress. The suppressive effect of glutamine supplementation on CD4+: CD8+ ratio and its positive effect on monocyte count after repeated bouts of exercise warrants further investigation. South African Journal of Sports Medicine Vol. 18 (4) 2006: pp. 122-12

The relationship between the perception of own locus of control and aggression of adolescent boys

Aggression is increasingly seen in most parts of South African society. Aggressive behaviour of boys in secondary school often results from frustrations caused by perceived high expectations of others regarding the role, locus of control, and personality of boys. Locus of control plays an important role in a person’s perception concerning a situation and possible reactions to what is happening, or should be happening. A 56-item questionnaire, based on Rotter’s “Locus of control” questionnaire, and the DIAS Scale were used. The questionnaire was completed by 440 boys in Grades 9, 10, and 11. Various factor, item and differential statistical analyses were conducted. Three constructs were identified, i.e. physical, verbal, and indirect aggression. Results indicated that locus of control has a significant influence on verbal and indirect aggression. The differential analysis indicated that contextual variables (language of tuition, age, and grade) play a significant, but not substantial, role in aggression. Furthermore, boys with an internal locus of control are significantly and substantially less aggressive than boys with an external locus of control, with respect to physical, verbal and indirect aggression

Die wese van godsdienssin - ’n empiriese studie

In this article the following issues concerning the essence of religiosity are considered: faith, trust, decision making, knowledge of principles, commitment, direction, hope, peace, meaning and security. The respondents used in this study were politicians, businessmen and teacher educators from all sectors and regions of South Africa. Higher order factor analysis and item analysis were used to evaluate the validity and reliability of the questionnaire. Subsequently differential differences were investigated by applying Hotelling's T-square test followed by the Student t-test as well as Multivariate Analysis of Variance (ANOVA) and Scheffe. Significant differences in the degree of religiosity were found between language and religious groups, as well as between respondents with different educational qualifications and between those living in urban and rural areas. Ministers of religion should note that it is essential to guide believers to a greater commitment and to the religious seeking of meaning and peace. The correct knowledge of and insight into the essence of religiosity will lead to attaining this goal

The effect of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under isoflurane anaesthesia in an ovine model

Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsThe effects of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under steady-state isoflurane anaesthesia were compared with the awake state. Six studies each were conducted in two cohorts of adult ewes: awake sheep and those anaesthetized with 2% isoflurane anaesthesia. In random order, each animal received ramped infusions of adrenaline, noradrenaline (0-40 µg/min) and dopamine (0-40 µg/kg/min). Cerebral blood flow was measured continuously from changes in Doppler velocities in the sagittal sinus. Autoregulation was determined by linear regression analysis between cerebral blood flow and mean arterial pressure. Isoflurane did not significantly alter cerebral blood flow relative to pre-anaesthesia values (P>0.05). All three catecholamines significantly and equivalently increased MAP from baseline in a dose dependent manner in both the awake and isoflurane cohorts. Although adrenaline significantly increased cerebral blood flow from baseline in the awake cohort (P0.05). Over a specific dose range, systemic hypertension induced by adrenaline, noradrenaline and dopamine did not significantly increase cerebral blood flow under 2% isoflurane anaesthesia. The concomitant administration of isoflurane and the catecholamines was not associated with altered autoregulatory function compared to the awake state.http://www.aaic.net.au/Article.asp?D=200236

Cerebrovascular carbon dioxide reactivity in sheep: Effect of propofol or isoflurane anaesthesia

Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsPropofol and isoflurane are commonly used in neuroanaesthesia. Some published data suggest that the use of these agents is associated with impaired cerebral blood flow/carbon dioxide (CO₂) reactivity. Cerebrovascular CO₂ reactivity was therefore measured in three cohorts of adult merino sheep: awake (n=6), anaesthetized with steady-state propofol (15 mg/min; n=6) and anaesthetized with 2% isoflurane (n=6). Changes in cerebral blood flow were measured continuously from changes in velocities of blood in the sagittal sinus via a Doppler probe. Alterations in the partial pressure of carbon dioxide in arterial blood (PaCO₂) over the range 18-63 mmHg were achieved by altering either the inspired CO₂ concentration or the rate of mechanical ventilation. Cerebral blood flow/CO₂ relationships were determined by linear regression analysis, with changes in cerebral blood flow expressed as a percentage of the value for a PaCO₂ of 35 mmHg. Propofol decreased cerebral blood flow by 55% relative to pre-anaesthesia values (P=0.0001), while isoflurane did not significantly alter cerebral blood flow (88.45% of baseline, P=0.39). Significant linear relationships between cerebral blood flow and CO₂ tension were determined in all individual studies (r2 ranged from 0.72 to 0.99). The slopes of the lines were highly variable between individuals for the awake cohort (mean 4.73, 1.42-7.12, 95% CI). The slopes for the propofol (mean 2.67, 2.06-3.28, 95% CI) and isoflurane (mean 2.82, 2.19-3.45, 95% CI) cohorts were more predictable. However, there was no significant difference between these anaesthetic agents with respect to the CO₂ reactivity of cerebral blood flow.J. A. Myburgh, R. N. Upton, G. L. Ludbrook, A. Martinez, C. Granthttp://www.aaic.net.au/Article.asp?D=200137

Access to health care in South Africa - the influence of race and class

Objectives. The first democratic government elected in South Africa in 1994 inherited huge inequities in health status and health provision across all section of the population. This study set out to assess the impact of the new government's commitment to address these inequities and implement policies to improve population health in general and address inequities in health care in particular. Design. A 1998 household survey assessed many aspects of health delivery, including their own perceived and actual access to health care among different segment of South Africa society. Results. Race was the main predictor of perceived changes in access to health care, with black, coloured and Indian respondents significatly more likely to feel that access had improved since 1994, compared with white respondents. Socio-economic status (SES) was the main predictor of actual access to health care, with low and middle SES classes significantly less likely to access care when ill. Conclusions. One-third of respondents perceived health care access to have improved between 1994 and 1998, and this response was partially determined along racial lines. About one-quarter reported an inability to access health care when they required it, and this response was partially determined along socio-economic lines. This set of contrasting responses suggests that at a political level perceptions are largely influenced by race, but at the operational level actual access is influenced by SES

Mountain bike racing - the influence of prior glycogen-inducing exercise and glutamine supplementation on selected stress and immune parameters

Objective. To investigate the effect of pre-exercise glutamine supplementation and the influence of a prior acute bout of glycogen-reducing exercise on the general stress and immune response to acute high-intensity cycling. Design. Randomised, double-blind, cross-over supplementation study. Setting and intervention. Subjects performed a series of 4 simulated mountain-bike races lasting &#8776;60 minutes each on separate days 1 week apart, with/ without prior glycogen- reducing exercise on a known outdoor course with/ without pre-exercise glutamine supplementation. Blood samples were collected pre- and immediately post-exercise after each race. Main outcome measures. Circulating concentrations of cortisol (COR) and dehydroepiandrosterone-sulphate (DHEAS) were assessed at all time points, as well as changes in white blood cell (WBC) subpopulation distribution. Results. COR was elevated in all groups post-exercise (p < 0.0001), but neither glycogen reduction, nor glutamine supplementation had any effect. DHEAs increased post-exercise (p < 0.05), with a greater relative increase in glutamine-supplemented subjects (p = 0.07). Total WBC and neutrophil counts in all groups were elevated after exercise (both p < 0.0005). Glutamine supplementation had no effect on differential WBC counts or distribution, but total WBC (p = 0.06) and monocyte (p < 0.05) counts showed greater increases after glycogen reduction. Gluta- mine supplementation was associated with greater postexercise decreases in CD4+ count (p = 0.07) and CD4+: CD8+ ratio (p = 0.01) after glycogen-reducing exercise. Conclusions. We conclude that pre-exercise glutamine supplementation may have an anticortisol effect by enhancing the DHEAS response to exercise stress. The suppressive effect of glutamine supplementation on CD4+: CD8+ ratio and its positive effect on monocyte count after repeated bouts of exercise warrants further investigation. South African Journal of Sports Medicine Vol. 18 (4) 2006: pp. 122-12

Response of Grape and Wine Phenolic Composition in Vitis vinifera L. cv. Merlot to Variation in Grapevine Water Status

Grape and wine phenolic composition was monitored over two consecutive seasons in Vitis vinifera cv. Merlotfollowing application of irrigation treatments that produced seasonal average stem water potentials rangingbetween -0.7 MPa and -1.4 MPa. Fresh weight of berries was significantly reduced in response to water deficit,primarily due to decreases in pericarp weight. Increases in the concentration of grape anthocyanins andflavonols in response to water deficit were found when expressed per unit grape berry fresh weight. Skin-derivedtannin concentration in grape berries was not affected by the irrigation treatments. The concentration of grapederivedphenolics was monitored during five days of fermentation in a small-lot winemaking experiment. Duringfermentation, the concentration of anthocyanins and flavonols in wine were highest in the non-irrigated and lowfrequency-irrigated treatments, which was reflected in changes in the wine colour of ferments. Finished winesfrom non-irrigated and low frequency irrigated grapevines showed increases in bisulphite-resistant pigmentswhen compared with those irrigated at a high frequency, but differences in phenolic composition were minor.Increases in bisulphite-resistant pigments were associated with increases in vitisin A and polymeric pigmentin the first and second seasons of the study respectively. Ageing of wines for an 18-month period increasedbisulphite-resistant pigments, and treatment differences in wine colour density were enhanced, such thatincreases in both parameters were associated with the non-irrigated and low-frequency-irrigated treatments