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Biomedical subjects

B Leon

Publications and source records attributed to B Leon.

7 recordsLinked to original sources
PubMed1995

The changing medical student population at the University of Cape Town.

OBJECTIVE: Since 1981, the composition of applicants and students admitted to the medical school of the University of Cape Town has changed gradually. The objective of this paper is to quantify these changes and explore possible reasons for them. DESIGN: A retrospective analysis of the actual data accumulated at each annual intake was performed and the trends determined. SETTING: Only data for the University of Cape Town medical school were evaluated. Data published by similar institutions were used for comparative purposes. RESULTS: The number of applicants has risen steadily from 1,229 in 1981 to 2,330 in 1994, so that the applicant/admission ratio now stands at 12,1:1. During this same period, the percentage of women in the class has increased, with women outnumbering men in both 1992 and 1993. In 1994, black African students comprised 24% of those admitted to the M.B. Ch.B. programme, and of these 30.4% were women. By comparison, their white colleagues constituted 45.3% of the class, 57.5% of this cohort being women. CONCLUSIONS: The composition of the 1st-year M.B. Ch.B. class at the University of Cape Town has become multiracial in character, a factor achieved partly through academic support and affirmative action. The heterogeneity of the class, particularly in respect of gender, language and socio-economic factors, while appropriate and necessary, will have an impact on the university and the profession.

Black or African American↗
PubMed1994

HDL and apolipoprotein A-I protect erythrocytes against the generation of procoagulant activity.

The appearance of anionic lipids on the extracellular surface of cells is required for the formation of the procoagulant complex that leads to the activation of prothrombin. Procoagulant activity would be expected to be inhibited by substances that stabilize the membrane structure and hence inhibit the transbilayer diffusion of phosphatidylserine from the cytoplasmic to the extracellular surface of the plasma membrane. The generation of procoagulant activity in human erythrocytes by A23187 and Ca2+ is inhibited by apolipoprotein A-I, its amphipathic peptide analogues, and high-density lipoprotein (HDL). These agents do not inhibit the Ca2+ loading of erythrocytes by A23187, nor do they inhibit the activation of prothrombin once the cells have been incubated at 37 degrees C with A23187 and Ca2+. Transbilayer diffusion of fluorescently labeled phosphatidylserine is inhibited by apolipoprotein A-I. These findings indicate that class A amphipathic helixes as well as lipoprotein particles and liposomes inhibit the transbilayer diffusion of phospholipids and procoagulant activity. This activity may contribute to the protective role of HDL against arteriosclerosis and thrombosis.

Amino Acid Sequence↗
PubMed1991

Self-planned experimentation (SPEX) practical classes in physiology.

A new form of undergraduate physiology practical experience is described. Students make their acquaintance with the physiological apparatus in the usual manner. At the end of the afternoon each group of four students is allocated an item of equipment with which to perform a true investigative experiment of their own choice, in their own time, the results of which are to be presented 2 weeks later by a randomly chosen member of the group. Students may investigate any question that can be answered using the resources available to them without endangering themselves or their subjects. Marks are awarded for the planning of the experiment (i.e. choice of controls, etc.), the correctness of graphical presentation of the results, the appropriateness of the statistical analysis, and for the discussion. There are no penalties for negative or unexpected results.

Education, Medical, Undergraduate↗
PubMed1983

Temperature regulation and water metabolism in the elephant shrew Elephantulus edwardi.

1. The Cape elephant shrew Elephantulus edwardi maintained a stable body temperature (37.6 C) over a wide range of ambient temperatures. 2. Normal eutherian mechanisms of temperature regulation were employed in the maintenance of homeothermy. 3. Water turnover rate and metabolic rate were lower than predicted for a similar-sized eutherian. 4. Maximal urine concentration was fairly high (3118 +/- 267 mOsm/kg) with urine osmolality largely dependent on the urea concentration. 5. Relative medullary thickness of the kidney (6.61 +/- 0.84) indicated a higher maximum urine concentration than found in the laboratory and reflected an arid habitat. 6. E. edwardi can be classed among the "advanced" homeotherms in view of the physiological adaptations employed for survival.

Animals↗