Previous studies from our laboratories indicate that the antidiabetic effects of Syzygium cordatum (Hochst.) [Myrtaceae] leaf extract in streptozotocin-induced diabetic rats may be attributed in part to mixtures of triterpenes, oleanolic acid (3ß-hydroxy-olea-12-en-28-oic acid, OA) and ursolic acid (3ß -hydroxyl-urs-12-en-28-oic acid, UA). For the bioactive compounds to have potential in diabetes management, they should alleviate or prevent complications of diabetes mellitus, kidney function, and cardiovascular disorders. This study was, therefore, designed to assess whether S. cordatum leaf derived OA influenced renal function evaluated by the ability to increase urinary Na + outputs parameters and creatinine clearance (Ccr) of streptozotocin (STZ)-induced diabetic rats. Extraction and fractionation of S. cordatum powdered leaf ethyl acetate-solubles (EAS) yielded mixtures of OA/UA and methyl maslinate/methyl corosolate. Recrystallization of OA/UA mixture using ethanol afforded OA, the structure of which was confirmed by NMR spectroscopy ( 1 H & 13 C). Acute effects of OA on kidney function and mean arterial blood pressure (MAP) were investigated in anesthetized rats challenged with hypotonic saline after a 3.5-h equilibration for 4h of 1 h control, 1.5 h treatment, and 1.5 h recovery periods. OA was added to the infusate during the treatment period. Chronic effects of OA were studied in individually caged rats treated twice daily with OA (60 mg/kg, p.o.) for five weeks. By comparison with respective control animals administration, OA significantly increased Na + excretion rates of non-diabetic and STZ-induced diabetic rats without affecting urine flow, K + and Cl − rates. At the end of five weeks, OA treatment significantly (p < 0.05) increased Ccr in non-diabetic (2.88 ± 0.14 vs. 3.71 ± 0.30 ml/min) and STZdiabetic rats (1.81 ± 0.32 vs. 3.07 ± 0.16 ml/min) with concomitant reduction of plasma creatinine concentration (n = 6 in all groups). OA also caused significant decreases in MAP in nondiabetic and STZ-induced diabetic rats. These findings suggest that OA may have beneficial effects on some processes associated with renal derangement of STZ-induced diabetic rats.

Studies from our laboratories indicate that Syzygium cordatum leaf extract contains triterpene mixtures [oleanolic acid (OA) and ursolic acid (UA)] with hypoglycemic properties. The aims of this study were to investigate the hypoglycemic effects of Syzygium aromaticum-derived OA and whether OA influenced the blood glucose lowering effects of insulin in streptozotocin (STZ)-induced diabetic rats. We envisaged that OA may provide a strategy with different mechanism of action for effective diabetic therapy because no single-marketed antidiabetic drug is capable of achieving long-lasting blood glucose control. The effects of various doses of OA and/or standard antidiabetic drugs on blood glucose were monitored in nondiabetic and STZ-induced diabetic rats given a glucose load after an 18-h fast. Rats treated with deionized water and standard antidiabetic drugs acted as untreated and treated positive controls, respectively. Blood glucose concentrations were measured at 15-min intervals for the first hour and hourly thereafter for 3 h. Blood glucose concentrations were also monitored in animals treated with OA and/or standard antidiabetic drugs for 5 weeks. OA like insulin decreased blood glucose concentrations in nondiabetic and STZ-induced diabetic rats. Combined OA and insulin treatment had even greater antihyperglycemic response, suggestive of a synergistic effect of the two. After 5 weeks, STZ-induced diabetic rats exhibited hyperglycemia and depleted hepatic and muscle glycogen concentrations. OA treatment lowered the blood glucose with concomitant restoration of glycogen concentrations to near normalcy. Our results suggest that OA may have a role in improving insulin sensitivity. These findings merit further research in this field.

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Second-year medical students at the Nelson R. Mandela School of Medicine (Durban, South Africa) were given a brief to prepare oral presentations on topics related to disorders of the gastrointestinal tract and endocrine system in the form of "patient-doctor" role play and to submit written documents about their topics. This initiative was introduced to assist medical students in their application and understanding of physiology to clinical situations. The aims of the student presentations were to improve the understanding of the physiological basis of diseases; promote independent research, active, and group-based learning; encourage social interactions; and develop presentation and peer review skills. Students rose to the challenge, producing a variety of presentations reflecting a wealth of creativity, humour, sensitivity to local cultural issues, and analytic thinking skills. The quality of the supporting posters and computer-generated slides was outstanding. Numerous "fun" prizes for specific individual and group performances were given based on peer and staff evaluations. This exercise ran over a 5-yr period before the introduction of a problem-based learning medical curriculum. Student feedback obtained over these years is reported here. Students were asked to complete semistructured questionnaires, which elicited feedback on various aspects of the learning exercise, including whether it should be continued and how it could be improved upon, especially if they were in groups that did not function well. The feedback obtained revealed that most students perceived the presentations to be fun, informative, creative/innovative, and, most importantly, beneficial to their learning. The majority of students felt that this exercise improved their understanding of pathophysiology, taught them to research independently, and encouraged better class interactions and group learning. The inclusion of such initiatives is beneficial not only to students' understanding and their experience in studying physiology but also for the development of skills useful in their future careers.

Physiology is an integral component of any medical curriculum. Traditionally, the learning of physiology has relied heavily on systems-based didactic lectures. In 2001, the Nelson R. Mandela School of Medicine (NRMSM; Durban, South Africa) embarked on a problem-based curriculum in which the learning of physiology was integrated with relevant clinical scenarios. Students are expected to gain an understanding of physiology through self-directed research with only certain aspects being covered in large-group resource sessions (LGRSs). It has gradually become evident that this approach has resulted in significant gaps in students' understanding of basic physiological concepts. A survey of student perceptions of needs for physiology was undertaken to gain a better understanding of their perceived problems and also to inform them of proposed curricular changes. Students were asked to what extent they thought physiology was essential for their understanding of pathology, interpretation of patients' clinical signs and presentation of symptoms, and analysis of laboratory results. Students were also invited to detail the difficulties they experienced in understanding in LGRSs on clinical and physiological topics. The results of the survey indicate that greater interaction of students with experts is needed. In particular, students felt that they lacked the basic conceptual foundations essential for the learning and understanding of physiology, since the difficulties that the students identified are mainly terminological and conceptual in nature.