Toxic copper level increases erythrocyte glycolytic rate, glutathione production and alters electrolyte balance in male Wistar rats

BACKGROUND

Copper is a micronutrient vital to several cellular energy metabolic processes and drives erythropoiesis. However, it disrupts cellular biological activities and causes oxidative damage when in excess of cellular needs. This study investigated the effects of copper toxicity on erythrocyte energy metabolism in male Wistar rats.

METHODS

Ten Wistar rats (150-170 g) were randomly divided into 2 groups: control (given 0.1 ml distilled water) and copper toxic (given 100 mg/kg copper sulphate). Rats were orally treated for 30 days. Blood, collected retro-orbitally after sodium thiopentone anaesthesia (50 mg/kg i.p.) into fluoride oxalate and EDTA bottles, was subjected to blood lactate assay and extraction of red blood cell respectively. Red blood cell nitric oxide (RBC NO), glutathione (RBC GSH), adenosine triphosphate (RBC ATP) levels, RBC hexokinase, glucose-6-phosphate (RBC G6P), glucose-6-phosphate dehydrogenase (RBC G6PDH), and lactate dehydrogenase (RBC LDH) activity was estimated spectrophotometrically. Values (Mean±SEM, n = 5) were compared by Student's unpaired T-test at p < 0.05.

RESULTS AND CONCLUSION

Copper toxicity significantly increased RBC hexokinase (23.41 ± 2.80 µM), G6P (0.48 ± 0.03 µM), G6PDH (71.03 ± 4.76nmol/min/ml) activities, ATP (624.70 ± 57.36 µmol/gHb) and GSH (3.08 ± 0.37 µM) level compared to control (15.28 ± 1.37 µM, 0.35 ± 0.02 µM, 330.30 ± 49.58 µmol/gHb, 54.41 ± 3.01nmol/min/ml and 2.05 ± 0.14 µM respectively, p < 0.05). Also, RBC LDH activity (145.00 ± 19.88mU/ml), NO (3.45 ± 0.25 µM) and blood lactate (31.64 ± 0.91 mg/dl) level were lowered significantly compared to control (467.90 ± 94.23mU/ml, 4.48 ± 0.18 µM and 36.12 ± 1.06 mg/dl respectively). This study shows that copper toxicity increases erythrocyte glycolytic rate and glutathione production. This increase could be connected to a compensatory mechanism for cellular hypoxia and increased free radical generation.

Amelioration of thyroid dysfunction by magnesium in experimental diabetes may also prevent diabetes-induced renal impairment

Background

Diabetes mellitus has been reported to cause thyroid dysfunction, which may also impair renal function. Magnesium has been reported to exert ameliorative effects in diabetes mellitus. This study investigated thyroid and renal functions in experimental type-2-diabetic Wistar rats.

Methods

Experimental type-2-diabetes was induced using short duration high-fat (30%) diet feeding followed by single-dose streptozotocin (35 mg/kg i.p.). Fifty rats were randomly divided into five equal groups consisting of control, diabetes untreated, diabetes treated with either magnesium (250 mg/kg) or metformin (250 mg/kg) and diabetes treated with both metformin and magnesium simultaneously.

All treatments were carried out orally for 14days post-diabetes induction. Body weight and blood glucose was monitored using the tail tipping method before diabetes induction and thereafter on days 1,7,14 post-treatment respectively. Thereafter, blood samples were collected by cardiac puncture after light anesthesia into plain and EDTA sample bottles. Total protein, albumin, globulin (plasma) and insulin (serum) were assayed in all samples obtained. Thyroid stimulating hormone (TSH), triiodothyronine, thyroxine was also evaluated (n = 5/group) in serum while blood urea nitrogen (BUN), creatinine was assessed (n = 5/group) in plasma. Kidney homogenates were obtained per group and analyzed for renal superoxide dismutase (SOD), reduced glutathione (GSH) and lipid peroxidation (MDA). Kidney histology was also evaluated per group using both Haematoxylin and Eosin and periodic acid Schiff stains.

Results

Body weight, blood glucose, insulin, renal MDA was increased in diabetic untreated compared to other groups. Reductions (P < 0.05) in TSH, triiodothynine, Renal SOD and GSH levels where observed in diabetic untreated compared to other groups. Renal histology in diabetic untreated showed glomerula sclerosis, fused messengial cells and either collapsed tubular lumen or lumen with eosinophilic renal cast. These pathologies where partially reversed in the other experimental groups.

Conclusion

This study suggests that thyroid and renal impairment may be present in experimental type-2-diabetes. Treatment with oral magnesium may cause a partial restoration of thyroid function that may impede the development of renal dysfunction.

Pathophysiology of iron overload-induced renal injury and dysfunction: Roles of renal oxidative stress and systemic inflammatory mediators

Iron-overload has been recognized as a risk factor for organ dysfunction and damage resulting in diseases such as liver and heart disease, diabetes mellitus, and neurodegenerative diseases. This study investigated renal function and some systemic inflammatory indices in iron-overloaded male Wistar rats. Thirty animals were equally distributed into 3groups and treated daily i.p. with either normal saline (0.2 ml; control), iron (as ferrous sulphate) (15 mg/kg) or iron (30 mg/kg) for 21days respectively. Post-treatment, blood samples were obtained from each animal by cardiac puncture after light anaesthesia into plain sample bottles. Iron, ferritin, transferrin, creatinine, urea, albumin, total protein, interleukin-6 (IL-6), prostaglandins-E2 and tumor necrosis factor-α (TNF-α) were analysed in serum. Kidney homogenates were obtained per group and analysed for superoxide dismutase (SOD), total antioxidant capacity (TAC), reduced glutathione (GSH), lipid peroxidation (MDA) and nitric oxide (NO). Kidney histology was evaluated per group using both Haematoxylin and Eosin and periodic acid Schiff stains. Iron-overload caused a graded increase (p < 0.05) in serum iron, ferritin, transferrin, creatinine, urea, IL-6, TNF-α, TAC, MDA and NO levels as well as a reduction in albumin levels, renal SOD and GSH in groups 2 (iron 15 mg/kg) and 3 (iron 30 mg/kg) respectively compared to control. Histological evaluation of the kidney showed structural and tubular aberrations consistent with renal damage via inflammatory processes in iron overloaded rats. Our present study suggests that iron-overloading causes renal dysfunction by triggering the evolution of several inflammatory mediators which lead to a cascade of systemic and renal inflammatory processes that alter renal structure and function.

Metformin Effects are Augmented by Chronic Intermittent Cold Stress in High Fat Diet Fed Male Wistar Rats

This study investigated the effects of metformin on some glucose regulatory indices in high fat diet (HFD) fedmale Wistar rats exposed to room temperature and chronic intermittent cold stress (CICS). Thirty rats were randomly dividedinto 5 groups. Group 1(control) was maintained on standard rat chow while groups 2-5 were maintained on HFD for 8weeksrespectively prior to experimental procedures. Control, group 2(HFD untreated) and group 3(HFD+metformin (250mg/kg)were exposed to room temperature while groups 4(HFD untreated+CICS) and 5(HFD+CICS+metformin) were exposed toCICS for 21days. Blood glucose was monitored before initial exposure to HFD and on days 1,7,14 and 21 respectively.Blood samples (5mls) were thereafter collected by cardiac puncture following light ether anaesthesia, serum was obtainedand analysed for insulin, cortisol, and lipid profile using laboratory kits. Pancreatic β-cell function and insulin resistancewere estimated using the Homeostasis Model Assessment equations. It was observed that blood glucose reduced significantlyin groups 2-4 on day21 compared to day1 values. At day 21 post-treatment, insulin level and insulin resistance were increasedwhile cholesterol levels were reduced in all HFD groups compared to control. Cortisol was increased in group 2 but reducedin groups 3-4 compared to control. HDL was reduced in groups 2-3 while liver glycogen was increased in groups 2, 3 and 5compared to control. Beta cell function and muscle glycogen were increased while LDL and triglyceride were reduced ingroups 2-4 compared to control. In conclusion, metformin ameliorates high-fat diet (HFD) induced impairment of glucoseand lipid regulatory indices by facilitating an increase in the storage of glycogen in the liver and muscle. Chronic intermittentcold stress exposure in HFD rats does not ameliorate insulin resistance but reduces impaired glucose and lipid regulatoryindices likely through an increase in adaptive thermo-genic mechanisms. The actions of metformin in reducing stressfulstimulus and preventing pre-diabetes syndrome in HFD fed rats are augmented by exposure to chronic intermittent coldstress.

Oral Magnesium Treatment Reduces Anemia and Levels of Inflammatory Markers in Experimental Diabetes

Magnesium has been reported to improve glucose utilization in diabetes mellitus. However, information on its effects on anemic and inflammatory markers in diabetes mellitus is limited. This study investigated the effect of oral magnesium (Mg) treatment on some markers of anemia and inflammation in 25 male Wistar rats. Rats (200 ± 15 g) were randomly divided into five groups (n = 5). Group 1 was control (received orally 0.2 mL distilled water daily), group 2 (Diabetic Untreated), group 3 (Diabetic Mg treated-100 mg/kg bw), group 4 (Diabetic Mg treated-250 mg/kg bw), group 5 (Diabetic Insulin treated-1 IU/kg bw). Diabetes was induced with a single dose of alloxan (100 mg/kg intraperitoneal (i.p.)). All treatments were done for 14 days. Anemic and inflammatory markers were investigated on blood samples obtained from each animal using standard laboratory methods. Significant increase (p < 0.05) in total white blood cell (WBC) count was observed in diabetic untreated rats (7.67 ± 0.397 × 10⁹/L) compared to control (5.88 ± 0.25 × 10⁹/L), DMg 100 (5.86 ± 0.74 × 10⁹/L) and DMg 250 (5.06 ± 0.78 × 10⁹/L). Hemoglobin concentration, packed cell volume (PCV) and red blood cell (RBC) count was decreased (p < 0.05) in DU compared to control, DMg 100, and DI rats. Erythrocyte sedimentation rate (ESR) was significantly increased (p < 0.05) in DU compared to control, DMg 100, DMg 250, and DI groups. Fibrinogen level was increased (p < 0.05) in DU rats (0.44 ± 0.02 g/dL) compared to control(0.26 ± 0.02 g/dL). Values obtained in DMg 100 (0.30 ± 0.03 g/dL), DMg 250 (0.22 ± 0.04 g/dL), and DI (0.36 ± 0.02 g/dL) rats were comparable to control (0.26 ± 0.02 g/dL). Total protein, albumin, and globulin levels were decreased in DU rats compared to normal control, DMg 100, DMg 250, and DI rats. In conclusion, anemia and increased hematologic and metabolic inflammatory markers may be associated with untreated diabetes mellitus. Treatment of alloxan-induced diabetic rats with magnesium improved the anemic state and reduced hematologic and metabolic inflammatory markers.

Anti-oxidative and reno-restorative effects of physalis angulata (whole plant extract) in alloxan-induced diabetic male Wistar rats

Backgroiound: Hyperglycemia has been reported to increase protein glycation and generation of free radicals which predispose to diabetic renal dysfunction. Physalis ahgulata has been shown to have hypoglycacmic and anti-lipidemic properties but there is dearth of information regarding its effect on kidney functions in diabetes. This study investigated the anti-oxidative and reno-restorative effects of methanol extract of whole plant of Physalis angulata (MEPA) in alloxan-induced diabetic rats.

METHODOLOGY

Twenty male Wistar rats (150-180g) were randomly divided into four groups: Group 1 (control) received 0.2 ml distilled water, groups 2-4 were made diabetic by single intra-peritoneal dose of alloxan monohydrate (100mg/kg) and treated with 0.2 ml distilled water, 500 mg/kg MEPA and 150 mg/kg metformin respectively. All treatments were given orally for 14 days. Blood samples were collected from each animal through retro-orbital puncture. The serum obtained were analysed for fructosamine, glycated hemoglobin (HbAlc), creatinine and blood urea nitrogen (BUN). Kidney samples were harvested into cold phosphate buffer, homogenized and centrifuged at- 7500rpm for 15 minutes. The supernatant obtained was analyzed for malondialdehyde and superoxide dismutase (SOD) activities. Values were compared using ANOVA at P<0.05.

RESULTS

The MEPA-treated groups showed significant decrease (P<0.05) in blood glucose, kidney weights, fructosamine,. HbAlc, malondialdehyde, creatinine and BUN, while the body weights and SOD significantly increased (P<0.05) compared to diabetic untreated group.

CONCLUSION

Treatment with methanol extract of Physalis angulata (whole plant) reduced hyperglycemia, malondialdehyde and glycation end- products, which could have contributed to the development of diabetic nephropathy if diabetes is left untreated.

Effects of quail egg on kidney functions in alloxan induced diabetic Wistar rats

Abstract

INTRODUCTION

Uncontrolled diabetes mellitus has been reported to lead to renal dysfunction. Quail egg consumption has been reported to exert curative effects in some disease conditions like diabetes mellitus, tuberculosis, and asthma. This study investigated the effects of quail egg consumption on some kidney functions in alloxan induced diabetic rats.

METHODS

Forty male Wistar rats with an average weight of 170g were randomly divided into four groups. Groups A-Control, B-Diabetic untreated, C-Diabetic treated and D-Normal treated. Groups B and C were made diabetic with a single dose of alloxan monohydrate (100 mg/kg i.p). Raw quail egg was administered orally (5 ml/kg) to groups C and D for 14 days. Body weight and blood glucose were monitored during the study. Blood and kidney samples were obtained from animals in each group, and analyzed for total protein, creatinine, blood urea nitrogen (BUN), renal malondialdehyde (MDA) and superoxide dismutase (SOD). Data were analyzed using ANOVA at P < 0.05.

RESULTS

Diabetic group treated with quail egg showed significant (P < 0.05) increase in SOD, decrease in body weight, blood glucose, total protein, creatinine, BUN and MDA levels when compared to diabetic untreated group. However, values of these parameters obtained from diabetic group treated with quail were comparable to control.

CONCLUSION

Quail egg consumption significantly reduced hyperglycemia, serum total protein, creatinine, BUN, MDA and increased SOD activities in alloxan induced diabetic Wistar rats which suggests that it lowers blood glucose and ameliorates renal impairment in diabetes mellitus.

Effect of methanol extract of musa sapientum leaves on protein glycation and erythrocyte antioxidant status in alloxan-induced diabetic Wistar rats

BACKGROUND

Increased generation of free radicals from protein glycation has been associated with compromised integrity of erythrocytes in diabetes. Musa sapientum has been reported to possess anti-diabetic properties and this study investigated the effect of methanol extract of Musa sapientum on protein glycation and erythrocyte integrity.

METHODS

Forty-two male Wistar rats (180-200g) were randomly grouped into seven: 1 (control), 2 (diabetic untreated), 3 (normal extract-treated (250 mg/kg)), 4 (normal metformin-treated (150 mg/kg)), 5 (diabetic extract-treated (250 mg/kg)), 6 (diabetic metformin-treated (150 mg/kg)), 7 (diabetic insulin-treated (1 IU/kg)). Diabetes was induced with single intraperitoneal injection of 120 mg/kg alloxan. Animals were treated for 14 days and blood (3 mls) was collected from retro-orbital plexus to determine serum fructosamine level, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Glycated haemoglobin (HbA(1c)) level was estimated using a conversion formula. Animals were sacrificed thereafter by cervical dislocation and pancreatic tissues were excised and stained with haematoxylin and eosin for histological study. Statistical significance at P < 0.05 was analyzed by one-way ANOVA and Newman-Keuls' post-hoc test.

RESULTS

Diabetic rats treated with extract, metformin and insulin had significant reduction in serum fructosamine level by 62.64%, 74.63% and 56.05% respectively while HbA(1c) level reduced by 45.06%, 50.62% and 40.57% respectively. Activities of erythrocyte SOD and GPx were increased in the extract-treated group. Histological studies showed regeneration of islet cells in the diabetic extract-treated rat which was comparable to normal.

CONCLUSION

The extract inhibited protein glycation, regenerated the islet cells and improved erythrocyte antioxidant status in diabetic rats.

Anti-ulcerogenic mechanism of magnesium in indomethacin induced gastric ulcer in rats

The gastric mucosa is continuously exposed to various agents like food condiments, spices, alcohol, acids and drugs, some of which are implicated in the pathogenesis of gastric ulcer. Magnesium compounds commonly used as laxatives and antacids have been reported to prevent ulcer formation but the mechanisms underlying this potential is unknown. This study therefore seeks to evaluate the gastro-protective mechanism of magnesium in the stomach through its effect on the parietal and mucus cells. Thirty-six male albino rats divided into 6 groups of 6 rats each were used. Group 1 was control, Group 2 was ulcer induced and untreated, Group 3 was treated with 500mg/kg b.w magnesium alone, Group 4 was pre-treated with 500mg/kg b.w magnesium before inducing ulcer, Group 5 was pre-treated with 500mg/kg b.w magnesium and 20mg/kg omeprazole 4 hours before inducing ulcer, Group 6 was treated with 20mg/kg omeprazole 4 hours before inducing ulcer. Animals were sacrificed 6 hours after ulcer induction and their stomachs were removed for ulcer scoring and histological analysis. A significant reduction was observed in the ulcer scoring of magnesium pre-treated ulcerated rats (9.4±0.8) compared with ulcerated untreated (20.8±0.9) groups. Parietal cell count of magnesium pre treated ulcerated group significantly decreased (169.7±18.9) compared with ulcerated untreated group (310.5±34.7). Mucous cell count of magnesium pre-treated ulcerated group (264.6±8.3) significantly increased compared with ulcerated untreated group (170.0±17.7). This study shows that magnesium possesses anti-ulcerogenic properties due to its ability to reduce the number of parietal cell and increase mucous cell counts.

Anti-diabetic property of Methanol extract of Musa sapientum leaves and its fractions in alloxan-induced diabetic rats

Diabetes mellitus is a metabolic disorder resulting from necrosis of β-cell and insulin resistance at the cellular level. Musa sapientum has been shown to possess anti-diabetic properties, however, the mechanism of its action is unknown. The effect of Methanolic extract of Musa sapientum leaves (MEMSL) and its fractions were assessed for in vitro inhibitory activity of α-amylase enzyme, in vivo hypoglycemic properties and liver glycogen content in alloxan-induced diabetic rats. Dried plant powder of Musa sapientum was successively extracted using n-hexane, ethyl acetate, dichloromethane and methanol respectively. The filtrate obtained was evaporated using rotary evaporator and the extract was stored at 4°C until use. The methanolic extract obtained was further fractionated using column chromatography. In vitro alpha amylase inhibitory activity of the methanolic extract at different doses (2.5mg/ml, 5mg/ml, 10mg/ml, 25mg/ml and 50mg/ml) and column fractions (100ug/ml) were assessed and compared with that of acarbose (5mg/ml), a standard oral α-amylase inhibitor. Hypoglycemic activity and liver glycogen content was studied using alloxan -induced diabetic male rats treated with MEMSL (250mg/kg and 500mg/kg), column fractions F2 and F5 (100μg/kg) for 14 days respectively. Results obtained showed a dose -dependent increase in α-amylase inhibitory activity of the methanolic extract at 5, 10, 25 and 50mg/ml exhibiting 29%, 61%, and 72% and 80% inhibitory activities respectively. Column fractions 2 and 5 showed the highest α-amylase inhibitory activity of 79% and 74% respectively. The MEMSL at 250mg/kg and 500mg/kg exhibited 66% and 59% hypoglycemic activities respectively compared with diabetic controls. Fractions 2 and 5 showed 48% and 75% reduction in blood glucose level respectively. Liver glycogen in diabetic animals treated with MEMSL (250mg/kg and 500mg/kg), F2 and F5 were significantly increased (5.5±0.5, 5.9±0.7, 3.6±0.5, 8.0±0.4 mg/100gwt. liver) compared with Diabetic controls (1.2±0.3 mg/100gwt. liver) respectively suggesting an increase in glucose storage or reduction in glycogen breakdown. It seems possible that the anti-diabetic properties in the leaf extract of Musa sapientum and its fractions maybe due to the inhibition of α-amylase, increased storage of glucose as glycogen in the liver and/or reduced breakdown of liver glycogen stores.

Effect of magnesium on gastrointestinal transit time in normal and diabetic rats: possible mechanism of action

BACKGROUND

Many gastrointestinal complications in diabetes are connected to neurohumoral dysfunction resulting in abnormalities of intestinal motility, secretion and absorption. Minerals have been reported as essential cofactors for basic cellular reactions but there is dearth of information on effect of Magnesium on gastrointestinal transit time (GITT) and the mechanism of action.

METHODS

Sixty male albino Wistar rats (180 - 200g) were grouped into twelve of five animals each. Group 1 (control) received 0.2ml saline. Groups 2-6 were normal rats treated with magnesium sulphate (as magnesium) (500mg/kg), adrenaline (0.5mg/kg), magnesium (500mg/kg) and adrenaline (0.5mg/kg), prazosin (1mg/kg) and both magnesium (500mg/kg) and prazosin (1mg/kg) respectively. Groups 7 - 12 were diabetic rats treated as in groups 1- 6. Diabetes was induced intraperitoneally with alloxan (120mg/kg bwt).

RESULTS

There was significant (p<0.05) reduction in GITT index in normal rats treated with magnesium, prazosin and combination of magnesium and prazosin compared with control. Treatment with adrenaline alone produced significant increase in GITT. However treatment with both magnesium and adrenaline produced significant reduction compared with control. This reduction in GITT was similar to that obtained in magnesium only and prazosin only treated groups. Diabetic groups showed significant reduction in GITT in all treated groups except the adrenaline only treated group which produced significant increase in GITT.

CONCLUSION

The significant reduction in GITT produced by magnesium in both normal and diabetic animals was comparable to that produced by prazosin (an á-adrenoceptor antagonist) indicating that magnesium may be inhibiting gastrointestinal smooth muscle contraction through á-adrenoceptor antagonist pathway.

Effect of methanolic extract of Musa sapientum leaves on gastrointestinal transit time in normal and alloxan induced diabetic rats: possible mechanism of action

Disorders of gastrointestinal motility have been associated with diabetes mellitus. Hyperglycaemia particularly has been reported to inhibit gastrointestinal transit time while glibenclamide, a sulphonylurea and insulin, both increased transit time. Musa sapientum has also been reported as an antidiabetic agent but there is dearth of information on the effect of this plant on gastrointestinal motility. This study was therefore carried out to investigate the effect of methanolic extract of Musa sapientum leaves (MEMSL) on gastrointestinal transit time (GITT) in male albino rats with and without hyperglycaemia and to elucidate possible mechanism by which this extract functions. Fifty five albino rats were divided into 11 groups of five animals each. All animals were fasted for 24hrs before the begining of the experiment. Group 1 served as control; while the remaining groups (2 - 11) were treated with 250mg/kg; 500mg/kg MEMSL; diabetic control; diabetic treated with 250mg/kg; 500mg/kg MEMSL; diabetic treated with glibenclamide (5mg/kg); normal rats treated with nifedipine (50mg/kg); normal rats treated with calcium chloride (CaCl2) only (10mg/kg); groups 10 and 11 were both pretreated with CaCl2 and subsequently treated with 250mg/kg and 500mg/kg MEMSL respectively. All plant extracts used for treatments were dissolved in normal saline and administered orally using orogastric tube. Charcoal meal was used as marker in the estimation of GITT. The study showed significant decrease in GITT in the normal rats treated with 250mg/kg and 500mg/kg of extract. However, in the diabetic rats treated with 500mg/kg MEMSL, there was significant increase in GITT and this is comparable with the gut response to glibenclamide (5mg/kg). Musa sapientum extract produced significant decrease in transit time in the calcium chloride pre-treated normal rats and this is comparable to the effect observed in Nifedipine treated group. The significant reduction in GITT produced by MEMSL in the normal rats reflects a strong possibility of MEMSL acting as calcium channel antagonist through the voltage gated calcium channel which may be due to the presence of alkaloids, saponins, cardenolides. There is the possibility of the extract acting as an inhibitor of potassium channel at higher concentration as observed in glibenclamide treated groups.

Effect of Magnesium pre-treatment on alloxan induced hyperglycemia in rats

BACKGROUND

The role of vitamins and mineral supplementation in the prevention of diabetes mellitus is not well elucidated.

OBJECTIVE

The effect of prior administration of magnesium on alloxan induced diabetes was assessed in rats.

METHODS

36 Male albino rats were used for this study. The animals were divided into 6 groups of 6 animals each; group 1 was healthy control; groups 2 served as diabetic control. Animals in group 3 received magnesium (100 mg/kg) i.p one hour prior to alloxan (120 mg/kg) administration, group 4 were also received magnesium (150 mg/kg) i.p one hour prior to alloxan administration. Animals in group 5 received magnesium (100 mg/kg) i.p only; group 6 animals received magnesium (150 mg/kg) i.p only. Blood samples were obtained from all animals and plasma glucose levels were determined on Day 0 (prior to treatment), Day 2, Day 5, Day 7 and Day 10 after the commencement of treatment.

RESULTS

There was significant increase (P<0.001) in plasma glucose values in the alloxan treated group when compared with the control values. There was also a significant increase (P<0.01) in plasma glucose levels in the magnesium-pretreated (100 mg/kg and 150 mg/kg) diabetic groups when compared with healthy controls whereas there was a significant reduction (P<0.01) in plasma glucose level when compared with the diabetic control.

CONCLUSION

This study has shown that magnesium pretreatment may delay the onset and subsequently cause a reduction in hyperglycemia in alloxan induced diabetes. This effect of magnesium may be attributed to its role as a scavenger of highly reactive hydroxyl radicals generated through alloxan reactions, its potentiation of glutathione antioxidant production and its role as a calcium blocker.

Pretreatment effect of magnesium on alloxan induced hyperglycemia in rats

The role of vitamins and mineral supplementation in the management of Diabetes mellitus is not well elucidated. We therefore carried out a preliminary study to assess the effect of prior administration of Magnesium on induction of alloxan diabetes, a model of type 1 diabetes mellitus. Twenty Male albino rats were used for this study. The animals were divided into 4 groups of 5 animals each. Animals in group 1 were normal rats and were not given any treatment, these served as healthy control. Animals in group 2 were diabetic rats that were not given any treatment, they served as diabetic control. Animals in group 3 were treated with magnesium (100mg/kg) intraperitoneally one hour prior to alloxan (150mg/kg) administration. Animals in group 4 were given intraperitoneal injection of magnesium (100mg/kg) once, and blood samples were obtained one hour after administration. Blood samples were obtained from all animals after 48 hours and plasma glucose levels determined using the glucose oxidase method. There was significant increase (p<0.001) in plasma glucose level in the alloxan treated group when compared with the control. There was also a significant increase (p<0.01) in magnesium-pretreated diabetic group. However, there was a significant reduction (p<0.01) in blood glucose level 48 hours after alloxan administration in the magnesium pre-treated diabetic group when compared with the diabetic controls. Magnesium pretreatment may delay the onset of alloxan induced hyperglycemia and this may be due to the scavenging effect of magnesium on the highly reactive hydroxyl radicals (OH) which was generated through alloxan reaction.

Effect of diet of varying protein concentrations on the activity of erythrocyte membrane Ca2+Mg2+ ATPase in dogs

Alterations in protein diet have been reported to result in alterations in calcium homeostasis in the body. Ca2+Mg2+ATPase is an ubiquitous enzyme important in calcium homeostasis in the body. The effect of varying protein diet on the activities of Ca2+ pump across cell membranes is however yet to be fully elucidated. In this study, the activity of erythrocyte membrane calcium pump in response to varying protein concentration in diet was therefore studied in the dog. The study was carried out in 24 dogs, randomly divided into 4 groups. The groups were fed with diets containing 30%, 26%, 16% and 0% proteins (high, medium, low and zero) for six weeks respectively. Blood samples were collected from each animal to determine packed cell volumes, hematocrit, blood urea, electrolyte studies and erythrocyte ghost membrane studies. The effects of Ca2+ and ATP on the activity of Ca2+Mg2+ ATPase were determined in the isolated ghost membrane. The result of the study shows that there was a protein diet dependent increase in the activity of Ca2+Mg2+ ATPase in the presence and absence of ATP in all the groups with the highest activity recorded in the high protein diet group and the lowest activity observed in the zero protein group. There was also a protein diet dependent increase in the protein concentration of the membranes in all groups observed with the highest protein concentration recorded in the high protein diet group and the lowest activity observed in the zero protein group. There was a significant decrease in K+ concentration (P <0.05) and a significant increase in urea concentration of animals fed with high protein diet (P <0.05). There was also a significant increase (P <0.05) in HCO3- concentration in the animals fed with medium protein diet and no significant difference in the PCV and heamatocrit values in all groups. This study has shown that high protein diets increase the activity of the Ca2+Mg2+ ATPase in the presence and absence of ATP.

Anti-oxidant and anti-hyperglycemic activities of musa sapientum root extracts in alloxan-induced diabetic rats

Anti-hyperglycemic and anti-oxidant properties of methanolic (MEMS) and aqueous (AEMS) extracts of Musa sapientum roots were investigated in alloxan-induced diabetic rats. Thirty adult male Wistar albino rats divided into five groups of 6 rats each were used: group 1--non-diabetic untreated (controls), group 2--diabetic untreated, and groups 3, 4 and 5--diabetic rats treated with 250 mg/kg bodyweight MEMS and AEMS, and 500 mg/kg bodyweight glibenclamide (a standard anti-diabetic drug), respectively. There was severe progressive weight loss in the untreated diabetic rats, while the rats in all the treated diabetic groups gained weight. While there was progressive hyperglycaemia in untreated diabetic rats; with blood glucose levels reaching a peak of 335.5 +/- 1.1 mg/dl on day 7 post-induction, compared to 76.8 +/- 0.8 mg/dl on day 0, these values were reduced to 80.7 +/- 0.5, 86.6 +/- 0.6 and 86.8 +/- 0.5 in MEMS, AEMS and glibenclamide-treated diabetic rats 15 days post-treatment. Also there were decreases in serum lipid peroxidation and increases in serum superoxide dismutase activities in MEMS, AEMS and glibenclamide-treated diabetic rats 15 days post-treatment. Lesions observed in the organs of untreated diabetic rats include selective necrosis of pancreatic beta islet cells, hepatocellular degeneration and necrosis, glomerulonephrosis and cardiovascular degeneration. Treatment of diabetic rats with AEMS and glibenclamide caused a total mitigation, while treatment with the MEMS achieved partial but considerable reduction in the severity of the lesions. It is concluded that aqueous and methanolic extracts of Musa sapientum roots possess anti-diabetic activities comparable to glibenclamide.

Students admission grades and their performance at Ibadan University pre-clinical MBBS examinations

OBJECTIVE

The main objective of this study was to examine the admission grades in Senior School Certificate Examinations (SSCE) and Joint Admission Matriculation Board (JAMB) Examinations in relation to their performance at the pre-clinical class, at the University of Ibadan medical school. A descriptive, cross sectional study was carried out from December 1998-April 1999. Records of students' admitted into the medical school in 1991/92 session were studied. The results showed a stronger correlation in the performance of the students at the 100 level examination and the Part 1 MBBS examination with the SSCE grades than their JAMB scores. Students admitted on merit according to JAMB scores performed averagely better than their other counterpart with lower JAMB scores. This result demonstrated that the SSCE scores are a better predictor of performance at preclinical MBBS examination than the JAMB scores. More attention needs to be placed on the quality of SSCE scores during admission into the medical school.

Erythrocyte membrane protein alteration in diabetics

OBJECTIVES

To study the protein components of the erythrocyte membranes of diabetic Nigerians and to compare the results with the erythrocyte membrane protein components of normal healthy Nigerians.

DESIGN

Laboratory based cross-sectional study.

SETTING

Department of Medicine, University College Hospital (UCH), Ibadan and Biomembrane Research Laboratory, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria.

SUBJECTS AND METHODS

The study was carried out in patients with insulin-dependent diabetes mellitus--IDDM (Type 1 diabetes), non-insulin dependent diabetes mellitus--NIDDM (Type 2 diabetes) and healthy human volunteers (HHm), which served as controls. The subjects were aged 30-65 years. There were 12 subjects in each of the IDDM and NIDDM) and 18 subjects in the HHm group. Blood samples (20 ml per subject) were obtained from each subject and erythrocyte ghost membranes were isolated separately from each sample. Total erythrocyte membrane protein concentration of each sample was determined using bovine serum albumin (BSA) as standard. The protein components of the erythrocyte ghost membranes were determined using sodium dodecyl sulphate polyacrylamide gel electrophoresis.

STATISTICAL METHOD

All values given are the mean +/- standard deviation (+/- SD) of the parameters measured. Significance was assessed using Student's t-test and P values of 0.05 or less were taken as statistically significant.

RESULTS

The total protein concentration of HHm was 5.5 +/- 0.01 micrograms/ml, total protein concentration of IDDM was 4.5 +/- 0.01 micrograms/ml while NIDDM was 5.1 +/- 0.02 micrograms/ml. The spectrin alpha and beta-chain bands are heavily present in the healthy human erythrocyte membranes and are absent in the insulin dependent diabetic membranes. The ankyrin band, band six and below are more pronounced in IDDM and NIDDM but are relatively absent in the healthy humans.

CONCLUSIONS

The results obtained provide evidence of profound quantitative and qualitative alteration of the erythrocyte membrane proteins in diabetic Nigerians. This may likely have serious functional implications of the diabetic patients.

A comparative study of students' performance in preclinical physiology assessed by short and long essays

The performance of 540 medical (MBBS) and 55 dental (BDS) students in short essay questions (SEQs) in preclinical physiology was compared with their performance in long essay questions (LEQs). The cohort was made up of 88 repeating and 452 non-repeating MBBS students and 12 repeating and 43 non-repeating BDS students. The SEQs and LEQs used for the study were those administered to the students in the paper II of the Part I MBBS/BDS examination. The results showed that all the students did significantly better in LEQs than in SEQs. When the students were sub-divided into repeaters and non-repeaters, performance in LEQs was still significantly better in all cases, except in the BDS repeaters where the difference was not significant. The study also showed that the BDS students did significantly better than the MBBS students in LEQs. Further analysis showed that the latter was due to a much better performance in LEQ 4 by the BDS students. In the SEQs, MBBS non-repeaters did better than repeaters while the situation was reversed with the BDS students. For all categories of students, on no occasion was the mean score in the LEQs or the SEQs up to 20.0, which is the 50% score and pass mark in this examination. The likely reasons for the better performance of the students in LEQs than in SEQs were discussed. The better performance of the BDS students in LEQs is believed to be due to the double exposure time of the BDS students to the topics from which LEQ 4 is drawn. From our results, it was concluded that LEQs are more useful than SEQs in assessing these students. In addition, the highly significant cross-correlation between scores in questions 1, 2, 3 and 4 suggested that the inherent problem of examiners' subjective judgement in essay marking could be minimized in both SEQs and LEQs. Finally, failure to achieve a mean score of 50% (pass mark) in both SEQs and LEQs suggested that the students are weak in essay writing. Possible reasons for this were suggested.