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Biomedical subjects

K Moodley

Publications and source records attributed to K Moodley.

15 recordsLinked to original sources
PubMed2005

Measuring the geometry of the universe in the presence of isocurvature modes.

The cosmic microwave background (CMB) anisotropy constrains the geometry of the Universe because the positions of the acoustic peaks of the angular power spectrum depend strongly on the curvature of three-dimensional space. In this Letter we exploit current observations to determine the geometry in the presence of isocurvature modes. Most previous analyses assumed that the primordial perturbations were adiabatic. A priori one might expect that allowing isocurvature modes would substantially degrade constraints on the curvature. We find, however, that with additional data sets, the geometry remains well constrained. When the most general isocurvature perturbation is allowed, the CMB alone can only poorly constrain the geometry to . Including large-scale structure data, one obtains Ohm(0) = 1.07 +/- 0.03, and 1.06 +/- 0.02 when supplemented by supernova data and the determination of H(0).

Journal Article↗
PubMed2005

Informed consent and participant perceptions of influenza vaccine trials in South Africa.

BACKGROUND AND OBJECTIVES: There are few insights from sub-Saharan Africa on research participants' experiences of the informed consent process, particularly in the context of randomised controlled trials, where issues of randomisation and the use of placebos may be confusing concepts for participants. This study investigated the knowledge and perceptions of the informed consent process among individuals participating in influenza vaccine trials in two disadvantaged communities in South Africa. METHOD: Four to 12 months after completion of the trials, participants were contacted to return to participate in the informed consent study. The semistructured questionnaire administered to assess recall of trial procedures and the informed consent process covered key issues including: purpose of the study; awareness that the study was not part of routine treatment; voluntary nature of participation and freedom to withdraw; randomisation; placebos; and remuneration. RESULTS: A total of 334 participants (93% of the original vaccine trial sample; mean age 68 years, median level of education grade 8, 69% women) completed the questionnaire. Only 21% were able to recall that they were allocated randomly to the different treatment arms. Only 19% of those involved in the placebo controlled study had interpreted the concept of placebo as an inactive medication. CONCLUSION: Although a good general recall of trial concepts was demonstrated, only a small proportion of the participants correctly interpreted and recalled the concepts of randomisation and placebos. Informed consent in this and similarly disadvantaged communities may often be inadequate and new ways to improve understanding of the research process should be explored.

Administration, Intranasal↗
PubMed2004

Initial conditions of the universe: how much isocurvature is allowed?

We investigate the constraints imposed by current data on correlated mixtures of adiabatic and nonadiabatic primordial perturbations. We discover subtle flat directions in parameter space that tolerate large (approximately 60%) fractions of nonadiabatic fluctuations. In particular, larger values of the baryon density and a spectral tilt are allowed. The cancellations in the degenerate directions are explored and the role of priors is elucidated.

Journal Article↗
PubMed2003

HIV and AIDS--the ethical dilemma central to many issues in HIV/AIDS revolves around individual good versus societal good.

Using patient advocacy as a point of departure, there are three possible ethical options where the human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) is concerned: a 'strict advocacy' approach, a 'moderate advocacy' approach and a 'no advocacy' approach. In South Africa, a 'moderate advocacy' approach is favoured in general.

AIDS Serodiagnosis↗
PubMed2003

Respect for patient autonomy.

Respect for patient autonomy creates the following obligations: informed consent, confidentiality, truth-telling and effective communication. Patient autonomy is becoming increasingly important in postmodern medicine and is changing the nature of the doctor--patient relationship.

Communication↗
PubMed2001

Constraining isocurvature perturbations with cosmic microwave background polarization.

The role of cosmic microwave background polarization data in constraining the presence of primordial isocurvature modes is examined. While MAP will be unable to simultaneously constrain isocurvature modes and cosmological parameters, PLANCK will set strong limits on isocurvature modes. If one allows isocurvature modes, the recently obtained BOOMERANG measurement of the curvature of the Universe fails. However, a comparably sensitive polarization measurement on the same angular scales will permit a determination of the curvature without the prior assumption of adiabaticity.

Journal Article↗
PubMed2001

Cardiovascular and diuretic activity of kaurene derivatives of Xylopia aethiopica and Alepidea amatymbica.

The extractives, crude and pure, of Alepidea amatymbica (AA) and Xylopia aethiopica (XA) were subjected to bioassay-directed phytochemical examination for potential cardiovascular and diuretic activity. All extractives and derivatives (XA/O, AA/1, xylopic acid, AA/3, AA/4, AA/5, AA/6, XA/1, XA/2, XA/3) displayed low toxicity, with LC(50) 0.5-5.0 ng/ml. For the first time, diterpene kaurenoids were reported to have significant systemic hypotensive and coronary vasodilatory effect accompanied with bradycardia. These effects were attributed to calcium antagonistic mechanism. The diuretic and natriuretic effects found were similar to the effects of chlorothiazide, suggesting inhibition of Na+ and K+ reabsorption in the early portion of the distal tubule. Further experiments are needed to elaborate the exact mechanisms of the hypotensive and diuretic effects of diterpene kaurenoids.

Animals↗
PubMed2000

The effect of protein-energy malnutrition on development of hypertension, glucose metabolism and insulin sensitivity in genetically hypertensive rats.

BACKGROUND AND AIM: The objective of the study was to elucidate the beneficial effect of protein-energy malnutrition (PEM) on development of hypertension in a genetic model of salt-sensitive hypertensive rats by evaluation of glucose metabolism and insulin sensitivity. METHODS AND RESULTS: Dahl Salt-Resistant (DSR) and Salt-Sensitive (DSS) rats were subjected to a low-protein (LP) diet (protein--5.8%, sucrose--51% and fat--7%) for 2 months. Two DSR and DSS groups on a normal protein (NP) diet and pair-fed animals served as controls. Glucose metabolism and insulin sensitivity were assessed by the euglycemic clamp technique. The results showed: DSR rats on the LP diet displayed significantly decreased systolic blood pressure (SBP), and decreased plasma insulin and blood glucose levels with significantly increased overall peripheral glucose utilization and glucose clearance. The pair-fed DSR followed the pattern of DSR on the LP diet with decreased SBP. The most interesting SBP results were shown in the pair-fed DSS rats, which despite low food intake and body weight gain developed hypertension similar to DSS on the NP diet. DSS rats on the LP diet also failed to develop hypertension by contrast with the DSS rats on the NP diet and pair-fed DSS rats. DSS rats on the LP diet significantly improved their insulin sensitivity to the level of DSR rats with significantly increased glucose utilization and glucose clearance. In both DSR and DSS groups on LP and pair-fed, a significant increase of heart rate was found. This was more pronounced in the DSS groups. CONCLUSIONS: The beneficial effect of PEM on development of hypertension is attributed to increased glucose utilisation and improved insulin sensitivity.

Animals↗
PubMed1999

Dose-dependent effect of dietary fish-oil (n-3) polyunsaturated fatty acids on in vivo insulin sensitivity in rat.

The objective of this study was to assess the effect of dietary fish oil (n-3) polyunsaturated fatty acids (PUFA) on in vivo glucose metabolism and insulin sensitivity of rats. The experiments were carried out on 18 Wistar male rats divided into three groups: control rats given a normal diet containing corn oil, and two experimental groups given 1% or 5% fish oil supplemented diets. Glucose metabolism and insulin sensitivity were assessed by euglycemic clamp technique on anesthetized animals. The results showed: 1) despite the normotensive state of the animals, a significant decrease in blood pressure, especially systolic, and decreased heart rate in both experimental groups; 2) significantly decreased plasma total and LDL cholesterol and nonsignificantly decreased plasma triglycerides; 3) significantly increased bleeding time; 4) normoglycemia and dose-dependent hypoinsulinemia; and 5) significantly increased and dose-dependent in vivo glucose utilization and glucose clearance, significantly increased insulin sensitivity. The above results suggesting that insulin production is suppressed, provide another possible explanation for the beneficial effects of fish oil via modulation of the well-known damaging cardiovascular effects of insulin.

Animals↗
PubMed1999

Constraints facing the female medical practitioner in private family practice in the Western Cape.

OBJECTIVES: To assess the existence and extent of employment-related problems facing female family practitioners in the context of a rapidly growing number of female doctors in South Africa. SUBJECTS AND METHODS: A descriptive survey was conducted using bilingual questionnaires. These were posted to all 280 female family practitioners in private practice in the Western Cape. RESULTS: Of the 280 questionnaires posted 169 were returned, but 45 of these were missampled. A response rate of 53% was obtained. The largest age category was 30-39 years. Of those not in solo practice, 68 (75%) were able to negotiate the terms of their working hours, 13 (19%) negotiated sick leave on commencing work, and only half had paid leave. Vacation leave was negotiated by 34 (50%), while only 6 (9%) discussed maternity leave with employers or colleagues. Of the 124 practices included in the survey, 6 (5%) had formal arrangements to cope with maternity leave. One hundred and seven respondents (86%) felt there was a need for maternity leave guidelines in the private sector in South Africa. Regarding practice-related problems, 33 female family practitioners (27%) reported some incidents of sexual harassment by patients. Despite these constraints, 88 respondents (71%) planned to continue working in this field. CONCLUSION: Definite obstacles exist in private family practice with regard to working conditions, in particular the lack of national regulations regarding maternity leave and the absence of legislation on pregnancy discrimination. This has important implications for the inclusion of female doctors in group practices and managed health care organisations--private primary health care of the present and future!

Adult↗