Cephas Musabayane
In memory of

Cephas Musabayane
University of KwaZulu-Natal | ukzn

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Introduction
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Publications

Publications (80)
Article
Abstract The tight glycemic control required to attenuate chronic complications in type 1 diabetes mellitus requires multiple daily injections of bolus insulin which cause hyperinsulinemic edema and hypertension due to Na(+) retention. Reports indicate that pectin insulin (PI)-containing dermal patches sustain controlled insulin release into the bl...
Article
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Purpose: Studies in our laboratory are concerned with developing optional insulin delivery routes based on amidated pectin hydrogel matrix gel. We therefore investigated whether the application of pectin insulin (PI)-containing dermal patches of different insulin concentrations sustain controlled release of insulin into the bloodstream of streptoz...
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Abstract Studies indicate that hyperglycemia-induced oxidative stress triggers the development of microvascular and macrovascular complications in diabetes. Accordingly, we hypothesized that maslinic acid (MA) prevents these complications due to its antioxidant properties. We, therefore, investigated the effects of 5-week MA treatment of streptozot...
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Recent reports suggest that the hypoglycaemic effects of the triterpenes involve inhibition of glucose transport in the small intestine. Therefore, the effects of Syzygium spp-derived triterpenes oleanolic acid (OA) and maslinic acid (MA) were evaluated on carbohydrate hydrolyzing enzymes in STZ-induced diabetic rats and consequences on postprandia...
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Mimusops caffra E. Mey. ex A.DC and Mimusops obtusifolia Lam (both members of the Sapotaceae family), and Hypoxis colchicifolia Bak (family Hypoxidaceae) are used by traditional healers in Zululand to manage malaria. Anti-plasmodial investigation of the crude extracts and some triterpenes isolated from the plants showed activity against a chloroqui...
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Diabetes mellitus is one of the most common chronic global diseases affecting children and adolescents in both the developed and developing nations. The major types of diabetes mellitus are type 1 and type 2, the former arising from inadequate production of insulin due to pancreatic β-cell dysfunction, and the latter from reduced sensitivity to ins...
Article
Background: In the present study, we investigated the effects of oleanolic acid (OA), which has hypoglycemic properties, on glucose transport and glycogen synthesis in the small intestine, an organ that secretes enzymes involved in carbohydrate metabolism. Methods: The OA was isolated from Syzygium aromaticum ethyl acetate-soluble fractions foll...
Article
Studies indicate that Syzygium spp-derived oleanolic acid (OA) enhances renal function of streptozotocin (STZ)-induced diabetic rats as evidenced by its reversal of the previously reported inability of the kidney to excrete Na(+) in these animals. We postulated that OA influences Na(+) excretion in the proximal tubule, the site where two-thirds of...
Article
Studies indicate that the antihyperglycemic effects of Syzygium aromaticum-derived oleanolic acid (OA) are mediated in part through increased hepatic glycogen synthesis. Accordingly, this study assessed the influence of OA on the activity of glucokinase (GK) and hexokinase (HK) of skeletal muscle and liver tissues in streptozotocin (STZ)-induced di...
Article
Artemisinin combination therapies have decreased malaria associated morbidity and mortality in several parts of the world. On the other hand, malaria cases have increased in sub-Saharan Africa largely due to falciparum resistance to the most frequently used drugs (chloroquine and sulphadoxine/pyrimethamine (SP) combination). Therapeutic failure has...
Article
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 insuli...
Article
Diabetes mellitus, a disorder characterized by chronic hyperglycemia and excessive urine excretion, is associated with complications such as atherosclerosis, cardiac dysfunction, and nephropathy. Renal disease, which develops through a number of metabolic pathways in diabetes, is characterized by functional as well as structural abnormalities of th...
Article
Objective. To evaluate the effects of Helicrysum ceres root and leaf extracts on mean arterial blood pressure and renal fluid and electrolyte handling in anesthetized male Sprague-Dawley rats. Design. Cross sectional study. Setting. Departments of Physiology and Pharmacy, University of Zimbabwe. Subjects. Eight separate groups comprising of control...
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The purpose of this study was to examine the in vivo effects of Ekebergia capensis leaf ethanolic extract (EKE) on the blood pressure of anaesthetised normotensive male Wistar rats and conscious weanling Dahl salt-sensitive (DSS) rats, which develop hypertension as they age. To investigate possible mechanism(s) of the extract’s hypotensive effects,...
Article
Previous studies from our laboratories indicate that the anti-diabetic 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 t...
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Summary The aim of this study was to examine some in vivo and in vitro cardiovascular effects of Helichrysum ceres leaf ethanolic extract (HCE) in experimental animal paradigms. The acute effects of HCE on blood pressure were studied in anaesthetised normotensive male Wistar rats challenged with intravenous hypotonic saline infusion after a 3.5-hou...
Article
Studies in our laboratories suggest that Sclerocarya birrea stem-bark ethanolic extract (SBE) has hypoglycemic properties. Accordingly, we investigated the effects of SBE on major complications of diabetes mellitus; blood glucose, renal function and mean arterial blood pressure (MAP) in non-diabetic and STZ-induced diabetic rats. Oral glucose toler...
Article
Extracts of Persea americana Mill (Lauraceae) ("Avocado") have been traditionally used to treat hypertension and diabetes mellitus. Accordingly, we studied the hypoglycaemic and renal function effects of P. americana leaf ethanolic extracts (PAE) in STZ-induced diabetic rats. Oral glucose tolerance responses to various doses of PAE were monitored i...
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The cardiovascular effects of Persea americana Mill (Lauraceae) aqueous leaf extract (PAE) have been investigated in some experimental animal paradigms. The effects of PAE on myocardial contractile performance was evaluated on guinea pig isolated atrial muscle strips, while the vasodilatory effects of the plant extract were examined on isolated por...
Article
Previous observations indicate that Ficus thonningii (Blume) [Moraceae] stem-bark extracts may be useful in the control of diabetes mellitus. Accordingly, we investigated in some experimental animal paradigms the effects of F. thonningii stem-bark ethanolic extract (FTE) on renal and cardiovascular functions as complications of diabetes. Oral gluco...
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This study was undertaken to investigate some cardiovascular effects of Hypoxis hemerocallidea Fisch & CA Mey (Hypoxidaceae) corm (African potato) aqueous extract in experimental animal paradigms. The effect of the corm aqueous extract (APE) on myocardial contractile performance was evaluated on guinea-pig isolated atrial muscle strips in vitro; wh...
Article
Previous studies in our laboratories suggest that oral administration of some herbal extracts reduce blood glucose concentrations in rats, possibly by interfering with food consumption and/or gastrointestinal absorption of food. Accordingly, we monitored the amounts of food consumed and body weights in separate groups of nondiabetic and streptozoto...
Article
Current biomedical evidence suggests that Hypoxis hemerocallidea (Fisch. & C.A. Mey.) [Hypoxidaceae] (African Potato [AP]) corm extract may be useful in the management of type 2 diabetes mellitus. However, more recent reports have also indicated that certain herbal extracts attenuate the deterioration of kidney function in diabetes mellitus. Accord...
Article
The present study investigates the hypoglycaemic effect of Syzygium cordatum (Hochst.) [Myrtaceae] leaf extract in non-diabetic and streptozotocin (STZ)-induced diabetic rats. Oral glucose tolerance tests (OGGT) were conducted in non-diabetic and STZ-diabetic rats using orally administered glucose (1.4 g 100 g(-1) body weight) followed by either th...
Article
The aim of the present study was to investigate the suitability of amidated pectin matrix patch for transdermal chloroquine delivery in an effort to mask the bitter taste when orally administered. Chloroquine has easily measurable outputs that are linked to increased renal Na+ excretion. We thus monitored urinary Na+ output in separate groups intra...
Article
To evaluate the effects of Helicrysum ceres root and leaf extracts on mean arterial blood pressure and renal fluid and electrolyte handling in anesthetized male Sprague-Dawley rats. Cross sectional study. Departments of Physiology and Pharmacy, University of Zimbabwe. Eight separate groups comprising of control and treated Male Sprague-Dawley rats...
Article
We previously demonstrated that Opuntia megacantha leaves' extracts can reduce blood glucose levels in diabetes mellitus. For O. megacantha leaves' extracts to have potential in the management of diabetes mellitus, it is necessary to establish its detailed effects on renal function since diabetes is associated with renal fluid and electrolyte distu...
Article
This study investigated the effects of long-term chloroquine and ethanol administration on renal fluid and electrolyte handling and kidney structure. Male Sprague-Dawley rats were orally administered with chloroquine diphosphate (20 microg kg(-1) bw) and/or ethanol (1.6 g kg(-1) bw) every third consecutive day for 4 weeks. Urine volume and total ur...
Article
Current evidence in literature suggests that acute effects of either chloroquine or ethanol on kidney function partly depend on influencing plasma concentrations of arginine vasopressin (AVP). Therefore, the goal of the current study was to explore the effects of chloroquine and/or various doses of ethanol on plasma AVP levels and associated effect...
Article
Chloroquine inhibits platelet aggregation in vitro and in vivo. Because inhibition of platelet aggregation may prolong bleeding time, the effect of chloroquine administration on bleeding time and disappearance of platelet serotonin, which may affect bleeding time, were studied. Platelets were harvested from 12 rabbits. They were labelled with (111)...
Article
The purpose of the study was to investigate the effects of Opuntia megacantha leaf extracts on blood glucose concentrations and kidney function in normal and streptozotocin (STZ)-diabetic rats. STZ-diabetic and non-diabetic rats were orally administered extracts of O. megacantha leaves (20 mg/100 g body weight) daily for 5 weeks and respective cont...
Article
A survey of 515 non-pregnant women at 12 geographically chosen research sites in rural Mashonaland shows significant differences in mean blood pressure, controlled by age cohorts. Three levels of economic development are identified: (1) the traditional economy on communal lands, with lowest blood pressure, (2) the wage economy in areas of large-sca...
Article
We postulated that chloroquine and/or ethanol affect plasma arginine vasopressin (AVP) concentrations to alter renal function. Therefore, we studied the effects of chloroquine and/or ethanol on plasma AVP concentrations and fluid, urinary Na(+) and K(+) outputs in separate groups of anaesthetized Sprague-Dawley (SD) rats challenged with a continuou...
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Full-text available
Previous studies showed that acute chloroquine administration increases plasma arginine vasopressin (AVP) concentration in the rat without influencing urine flow rate. The present study was designed to investigate whether chloroquine inhibits the AVP-induced cAMP production that mediates the antidiuretic effects of vasopressin. Single inner medulla...
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Full-text available
We report successful oral administration of insulin entrapped in amidated pectin hydrogel beads in streptozotocin (STZ)-diabetic rats, with a concomitant reduction in plasma glucose concentration. The pectin-insulin (PI) beads were prepared by the gelation of humilin-pectin solutions in the presence of calcium. Separate groups of STZ-diabetic rats...
Article
To investigate the effects of crude extracts of the root and stem of Olea africana on mean arterial pressure (MAP) and heart rate in normo and hypertensive rats. Comparative study. Laboratory. 40 Sprague Dawley rats of either sex (150 to 250 g) randomly assigned to normotensive (n = 15) (DOCA) -salt hypertensive (n = 25) groups. The normotensive gr...
Article
We measured and compared lung function indices and some blood parameters (gases, electrolytes, glucose, pH, red cell indices) of 54 male small-scale miners (SSM) chronically exposed to chrome ore dust to those of 50 nonmining control subjects (NMC) and 46 large-scale chrome miners (LSM) who had taken internationally recommended precautionary measur...
Article
Background: Chloroquine inhibits platelet aggregation. Because platelet aggregation may lead to the lysis of platelets, the effect of chloroquine administration on circulating platelet survival was studied. Methods and Results: Platelets harvested from the blood of male inbred (WAG) rats were labeled with ¹¹¹ Indium oxine and returned to other inbr...
Article
To establish the effects of chloroquine on kidney function we monitored renal parameters in age and sex matched control subjects and patients who presented with acute transient fever. The patients were immediately treated with chloroquine diphosphate in the recommended dosage. Blood samples for creatinine, urea, Na+ and K+ determinations were colle...
Article
Full-text available
To perform lung function tests on tobacco farm workers (TFWs) chronically exposed to flue curing and stacking of tobacco leaves and to compare them with vegetable farm workers (VFWs) who were not exposed to any known air pollutant (control). Comparative study. Tobacco and vegetable farms. 20 TFWs and 30 VFWs. All subjects were male and the mean age...
Article
The aim of the present study was to delay the release of chloroquine to distal parts of the gastrointestinal tract by using a multiparticulate hydrogel formulation. Amidated pectin chloroquine beads (PC) with varying pectin-to-chloroquine ratios (PC) w/w loadings of 4:1, 2:1, and 1:1 in the dried beads were prepared by the gelation of drug-loaded p...
Article
We have previously suggested that the increase in renal Na+ excretion in response to physiological doses of arginine vasopressin (AVP) is not directly linked to the V2-mediated antidiuretic effect. In the present study we investigated the possible involvement of AVP V1 receptors in this natriuresis using a specific AVP V1 antagonist [1-(beta-mercap...
Article
The purpose of this study was to investigate the effects of various plant extracts of the genus used elsewhere on plasma glucose and serum insulin concentrations in normal and diabetic rats. Extracts of Solanum incarnum ripe fruit, Solanum incarnum roots, Opuntia megacantha leaves, Aloe chabaudii leaves, Morus alba leaves, Ficus thoningii bark, All...
Article
We postulated that chloroquine increases plasma arginine vasopressin (AVP) concentrations thus altering renal Na+ clearance. Therefore, we studied a relationship between plasma AVP concentrations and urinary Na+ output in separate groups of Sprague-Dawley (SD) rats administered chloroquine (3 micrograms/min) for 1 h 20 min. We also monitored Na+ ex...
Article
To determine the prevalence of pregnancy induced hypertension (PIH) in rural Zimbabwe. A blood pressure survey conducted in three socio-economic strata of rural Zimbabwe, communal lands, commercial farms and mining areas. Rural Zimbabwe, Mashonaland West Province. 627 pregnant (> 20 weeks gestation) and 483 non pregnant (ages 16 to 45) women. Preva...
Article
Primary infections, protein malnutrition or simply poor food intake which decrease albumin synthesis often prevail in rural Zimbabwe. Therefore, we postulated that serum albumin levels in rural folk may not compare with published values. To investigate this, blood samples were collected from 1,502 consenting participants aged between 16 and 90 year...
Article
Male Sprague-Dawley rats (300-400 g) were made diabetic by an i.p. injection of streptozotocin (STZ, 60 mg/kg in citrate buffer, n = 8) to examine renal function in well-established diabetes mellitus. Vehicle-injected animals (n = 8) acted as controls. The mean weekly total amounts of food taken by control and STZ-diabetic rats did not differ, but...
Article
The possibility of an interaction between oxytocin and aldosterone to influence renal Na+ excretion was investigated in Inactin-anaesthetized male Sprague-Dawley rats. Endogenous plasma concentrations of aldosterone were suppressed by either adrenalectomy or bicarbonate infusion. The effects of 2 h intravenous administration of oxytocin (0.04 pmol/...
Article
The effects of 3 consecutive days of oral chloroquine (1 mg/100 g body weight) on kidney function and blood pressure were studied in male Sprague-Dawley rats that were challenged with hypotonic saline infusion 24 h after the last chloroquine administration. The rats were anesthetized with Inactin [5 ethyl-5-(1'-methylpropyl)-2-thiobarbiturate, Byk...
Article
The effect of a 2-hour intravenous chloroquine infusion (0.015, 0.030 and 1.25 micrograms min-1) on renal fluid and electrolyte handling was investigated in the saline infused, Inactin anaesthetized rat. Blood pressure and glomerular filtration rate were not affected by chloroquine administration, remaining around 128 mmHg and 2.4 ml min-1, respect...
Article
The primary objective of this study was to determine the effect of acute alterations in sodium intake upon the blood pressure and hormone levels of young Zimbabwean men. Blood pressure, 24-h urinary electrolyte excretion and plasma concentrations of angiotensin II, aldosterone, and atrial natriuretic peptide were measured in normotensive black medi...
Article
Twenty-seven male and female black Zimbabweans hypertensive patients were matched by age and sex and compared to 27 normotensive subjects. All subjects were examined after dietary sodium depletion, followed by sodium loading. In addition to renin status and salt-sensitivity, urine aldosterone, renal prostaglandins, plasma atrial natriuretic peptide...
Article
The present study investigated the renal function in male Sprague-Dawley rats receiving continuous NaHCO3 (0.077 M) infusion. The renal effects of aldosterone administration in this preparation were also examined. Continuous NaHCO3 infusion significantly (p less than 0.01) depressed plasma aldosterone concentration to 2.36 +/- 1.22 nmol (n = 8) whe...
Article
The influence of aldosterone administration on urine flow, Na+ and K+ excretion was examined in hypotonic saline infused, Inactin anesthetised rats following removal of the adrenals or adrenals and posterior pituitary. Plasma adrenal steroid levels were considerably depressed but still detectable 10-14 days after adrenalectomy. Removal of the poste...
Article
A method for studying the renal action of AVP in the saline-infused conscious unrestrained rat is described. Conscious rats infused iv with 0.077 mol/l NaCl at 150 microliter/min had a plasma AVP concentration of 0.70 +/- 0.15 mol/l. AVP administration at 6 and 24 microU/min resulted in plasma AVP levels of 0.97 +/- 0.14 and 2.27 +/- 0.30 mU/l, res...
Article
1. Renal function and the effect of neurohypophysial hormone replacement was investigated in anaesthetized, acutely hypophysectomized, male rats. 2. Although urine production was only slightly lower over the 8 h post-operative study period in hypophysectomized rats, sodium excretion was greatly depressed reaching only 3.5 +/- 1.4 mumol/min compared...
Article
1. Renal function and the effect of oxytocin and vasopressin replacement have been examined in anaesthetized male neurohypophysectomized rats. 2. Rates of urine flow were higher but sodium excretion markedly lower in neurohypophysectomized rats than in intact animals receiving hypotonic saline infusion (33.8 +/- 2.3 vs. 27.0 +/- 0.7 ml and 472 +/-...
Article
Renal electrolyte excretion has been examined in water loaded ethanol anaesthetised rats receiving continuous iv saline (0.077 m NaCl) infusion. These animals exhibited very low rates of Na ⁺ , K ⁺ and Cl ⁻ excretion by comparison with Inactin anaesthetised rats. Water loaded Inactin anaesthetised rats also showed a degree of Na retention but both...
Article
The relationship of plasma vasopressin concentrations in the physiological range to renal electrolyte excretion was investigated. Unanaesthetized rats, when normally hydrated, were found to have a plasma vasopressin concentration of 1.13 +/- 0.15 mu u./ml. 16 h water deprivation raised this to 1.98 +/- 0.21 mu u./ml. Inactin-anaesthetized rats infu...
Article
Includes appendix of publications related to thesis. Thesis (D.Phil.)--University of Zimbabwe, 1987.