Pulmonary functions and anthropometric parameters of young male and female adults participating in moderate aerobic exercise

Respiratory disorders may be one of the adverse effects of sedentary lifestyle. This study investigated respiratory functions (FEV1, FVC and PEFR) and anthropometric parameters (body weight and body mass index) of healthy young males and females participating in moderate aerobic exercise. Forty young healthy untrained non-athletes, twenty males and twenty females (age, 25 ± 5.6 years; body weight, 65 ± 4.0 kg; body height, 176.9 ± 2.5 cm) volunteered to participate in this study. The exercise regimen was of moderate intensity lasting for 20 min daily on a treadmill consistently at the speed of 13 km/h for 14 days. The weight and height of participants were measured using medical scale and wall-mounted stadiometer respectively. The forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) were assessed using digital spirometer. The results showed a significant (p < 0.05) decrease in body weight and body mass index of female participants after 14 days of exercise regimen. The FEV1, FVC and PEFR were significantly increased (p < 0.05) in both male and female subjects after exercise. The Pearson correlation showed a significant (p < 0.05) positive correlation between BMI with FEVI/FVC% in female participants. There was an increase in calories burnt from day 4 of the study in both male and female participants. It is concluded that moderate aerobic exercise improved respiratory functions (FEV1, FVC and PEFR) in both male and female subjects with greater improvement in females while reducing body weight and body mass index in females.

Identification of phytochemicals and assessment of hypoglycemic and haematological potentials of Terminalia catappa Linn leaf extract in alloxan-induced diabetic Wistar rats

INTRODUCTION

Hypoglycemia and anemia are associated with diabetes mellitus. Medicinal plants and orthodox drugs have been used for the management of this disease. This study aimed to validate the ethnomedical claims of Terminalia catappa Linn. leaf extract in reducing hyperglycemia and hematological potentials in alloxan-induced diabetic rats and to identify likely antidiabetic compounds.

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography was used to identify the various phytochemical constituents. Male Wistar rats were randomly divided into five groups containing 6 rats per group. Group 1 (control) received 0.2 ml/kg of distilled water, group 2 received 130 mg/kg of T. catappa aqueous extract, groups 3-5 were diabetic and received 0.2 ml/g distilled water, 130 mg/kg T. catappa extract and 0.75 IU/kg insulin respectively for 14 days. Hematological parameters were measured and an oral glucose tolerance test was carried out using 2 g/kg body weight glucose. A histological analysis of the pancreas was done.

RESULTS

Twenty-five compounds identified as flavonoids, phenolic acids, tannins, and triterpenoids were detected. The blood glucose levels were significantly (p<0.05) elevated in DM groups but were significantly (p<0.05) reduced following Terminalia catappa leaves extract to DM groups. There was s significant (p<0.05) increase in insulin levels improved hematological parameters (RBC, WBC, and platelets), and increased islet population.

CONCLUSION

These results suggest that T. catappa extract has hypoglycemic, insulinogenic, and hematopoietic potentials in diabetic condition and offer protection to the pancreas which could be attributed to the phytochemical constituents thereby justifying its use in traditional therapy.

Profile of a Don - Prof. Eme Osim Retires

Prof Eme E. Osim served Editor-in-Chief of Nigerian Journal of Physiological Sciences between 1999 and 2009. This tribute highlights his immense contributions to the development of the journal and academia.

Cardiac and Renal Protective Effect of Vitamin E in Dexamethasone-Induced Oxidative Stressed Wistar Rats

Vitamin E has been used as antioxidant and in the treatment of various ailments due to oxidative stress. The cardio-protective effect of vitamin E in dexamethasone induced oxidative stress was studied. Forty Wistar rats were randomly assigned to four groups of 10 rats each. Control group received normal rat chow. Oxidative stress was induced using 30µg/kg body weight of dexamethasone (DEX) intraperitonealy in DEX+Vit E and DEX only groups while Vitamin E was administered orally at a dose of 300 IU/kg to Vitamin E only group and DEX+Vit E group daily for 14 days. All animals were fed ad libitum and had free access to water. Blood samples were obtained by cardiac puncture for biochemical analyses while heart and kidney were processed for histological staining.  The result shows a significant (p<0.05) decrease in serum nitric oxide, bilirubin and superoxide dismutase concentration in DEX-only group which was elevated following vitamin E treatment. The angiotensin converting enzyme and lactate dehydrogenase enzyme activities were significantly (p<0.01) elevated in DEX-only group compared with control and DEX+Vit E groups. These enzyme levels were significantly (p<0.01) reduced in DEX + vitamin E group. The histology of the heart and the kidney in DEX-only group showed cardiac hypertrophy and kidney injury but were ameliorated by vitamin E treatment. The results suggest that vitamin E has cardiac and renal protective effect and ameliorates oxidative injury to the heart and kidney due to oxidative stress.

Blood pressure-reducing activity of Gongronema latifolium Benth. (Apocynaeceae) and the identification of its main phytochemicals by UHPLC Q-Orbitrap mass spectrometry

Background Gongronema latifolium Benth. (family Apocynaceae) leaves (GL) has interesting medicinal properties. The effects of extracts from G. latifolium on blood pressure (BP) and the possible mechanisms of action were also investigated. Methods The ultrahigh resolution liquid chromatography orbitrap MS analysis was used to identify the phytochemicals present. Normotensive Wistar rats were anesthetized with sodium pentobarbitone (40 mg/kg) intraperitoneally, and the jugular vein was cannulated for infusion of drugs while the carotid artery was cannulated for direct BP measurement. GL extract (5-20 mg) alone or with nifedipine (10 mg/kg), atropine (2 mg/kg), L-NAME (5 mg/kg), methyl blue (3 mg/kg) and propranolol (1 mg/kg) were administered intravenously to Wistar rats and direct BP measurements were carried out. Results Systolic and diastolic BP levels (128/90 mm Hg; MAP 103 ± 3 mm Hg) and heart rates were all significantly (p < 0.01) decreased after GL administration. Raised mean arterial pressure (MAP) and heart rate by atropine, L-NAME and methyl blue were significantly (p < 0.01) reduced after GL administration, while propranolol significantly (p < 0.01) inhibited hypotension caused by GL. Infusion of GL reduced MAP (95 ± 3 mm Hg) comparable with nifedipine (93 ± 2 mm Hg), a calcium channel blocker. The phytochemicals identified were 34 compounds, including oleanolic acid derivatives, flavonoids, antioxidant fatty acids, 2 coumarins and 2 iridoids. Conclusions These results suggest that G. latifolium has hypotensive properties mediated by the synergistic activity of the compounds, probably via the β-adrenergic blockade mechanism.

Altered Potassium Ion Channel Function as a Possible Mechanism of Increased Blood Pressure in Rats Fed Thermally Oxidized Palm Oil Diets

Intake of thermally oxidized palm oil leads to cytotoxicity and alteration of the potassium ion channel function. This study investigated the effects of fresh and thermally oxidized palm oil diets on blood pressure and potassium ion channel function in blood pressure regulation. Male Wistar rats were randomly divided into three groups of eight rats. Control group received normal feed; fresh palm oil (FPO) and thermally oxidized palm oil (TPO) groups were fed a diet mixed with 15% (weight/weight) fresh palm oil and five times heated palm oil, respectively, for 16 weeks. Blood pressure was measured; blood samples, hearts, and aortas were collected for biochemical and histological analyses. Thermally oxidized palm oil significantly elevated basal mean arterial pressure (MAP). Glibenclamide (10^-5 mmol/L) and tetraethylammonium (TEA; 10^-3 mmol/L) significantly raised blood pressure in TPO compared with FPO and control groups. Levcromakalim (10^-6 mmol/L) significantly (p < .01) reduced MAP by 32.0% in FPO and by 5.4% in TPO. NS1619 (10 mmol/L) significantly (p < .01) decreased MAP by 19.5% in FPO and by 8% in TPO. The TPO significantly (p < 0.01) increased the tissue levels of peroxide, total cholesterol, triglyceride, and low-density lipoprotein cholesterol while catalase and superoxide dismutase activities were significantly (p < .01) decreased compared with control and FPO groups. Histological alterations were prominent in aortas and hearts of rats in the TPO group. These results suggest that prolonged consumption of repeatedly heated palm oil increases MAP probably due to the attenuation of adenosine triphosphate-sensitive potassium (K_ATP) and large-conductance calcium-dependent potassium (BK_Ca) channels, tissue peroxidation, and altered histological structures of the heart and blood vessels.

Effect of Vitamin C Supplementation on Platelet Aggregation and Serum Electrolytes Levels in Streptozotocin-Induced Diabetes Mellitus in Rats

Diabetes mellitus (DM) is a disease condition characterised by hyperglycemia; free radical and abnormalhaematological indices. Vitamin C can reduce free radical generation and ameliorate adverse conditions of diabetes mellitus.The aim of the present study is to investigate the effect of vitamin C on platelet aggregation and electrolyte levels in Type 1DM. Male Wistar rats were divided into four groups namely control, DM, DM +Vitamin C and Vitamin C groups. Rats weremade diabetic with a single dose of streptozotocin (65 mg/kg) intraperitoneally. Vitamin C was administered orally todiabetic and normal rats at 200 mg/kg body weight for 28 days. Blood samples were analyzed for hematological parameters,platelet aggregation, and serum electrolyte levels. Blood glucose in DM+ Vitamin C group (9.9 ± 1.8 mmol/L) wassignificantly reduced (p<0.01) compared to DM group (32.2 ± 2.1 mmol/L) and significantly higher (p<0.05) than control(4.4 ± 0.8 mmol/L). Haemoglobin (Hb) concentration in DM group (12 ± 0.1 g/dL) was significantly reduced (p<0.01) whencompared with control groups (14 ± 0.24 g/dL) and significantly increased (p<0.05) in the DM+vitamin C group (13.5 ± 0.5g/dL) compared with the diabetic group. The mean corpuscular volume values in DM (68.66 ± 0.5 fL) and DM+vitamin Cgroups (68.11 ± 0.4 fL) were significantly higher (p<0.01) than the control (59.49 ± 0.5fL). Platelet count in DM group (523± 8.5 x109/L) was significantly raised (p<0.01) when compared to control (356 ± 6.2 x109/L) and significantly reduced(p<0.01) in DM+ vitamin C-treated group (385 ± 7.8 x109/L) compared with DM group. Platelet aggregation and serumsodium/potassium ratios was significantly reduced (p<0.01) in DM+vitamin C compared with DM group. These resultssuggest that oral vitamin C administration increases haemoglobin, reduced plasma glucose level, platelet count, serumsodium/potassium ion ratio and inhibits platelet aggregation in streptozotocin-induced DM in rats.

Investigation of effects of time of measurement and modes of administration on cadmium accumulation in rat liver under some medicinal plants food supplemented diet

Context and Objectives:

Cadmium (Cd) toxicity leads to cell and organ damage, we comparatively examined the protection ability of different medicinal plants on Cd liver accumulation following different treatment interventions and modes of administration.

Materials and Methods:

Rats were fed either 7% w/w Zingiber officinale, 7% w/w Allium Sativum, 10% w/w Lycopersicon esculentum, 5%, w/w Garcinia kola (all in rat chow), while Cd (200 ppm) was given in drinking water. Additives were administered together with (mode 1), a week after (mode 2) or a week before metal exposure (mode 3) for a period of six weeks. Cd liver was determined using AAS and compared using analysis of variance (ANOVA).

Results:

All additives significantly (P <0.5) reduced the accumulation of Cd in the liver. After adjusting for time and mode of administration, mean %protection for week 4 was significantly lower by 14.1% (P=0.02) from that for week 2 but the means did not differ with respect to additive used or mode of administration, no statistically significant interaction between modes of administration and either of additives used or time of administration in their respective relationships to percentage protection from Cd.

Conclusion:

Additives significantly reduced Cd accumulation through a reduction in absorption and enhancement of metal excretion.

Attenuated vascular responsiveness to K+ channel openers in diabetes mellitus: the differential role of reactive oxygen species

The current study examined the responsiveness of blood vessels from diabetic rats to K+ channel openers and explored whether ROS might be involved in any changes. Responses were measured in aortic rings isolated from four weeks streptozotocin (65 mg/kg)-induced diabetic rats. Relaxation to levcromakalim (ATP-sensitive potassium channel KATP opener, 10(-9)-10(-5) mol/l) and (+/-)-naringenin (large conductance calcium-activated channel BKCa opener, 10(-8)-10(-3) mol/l) were recorded in phenylephrine (1 µmol/l) pre-contracted segments in the absence and presence of superoxide dismutase (SOD, 100 µmol/l) and apocynin (an antioxidant and inhibitor of NADPH oxidase, 100 µmol/l). Contractions to phenylephrine (10(-9)-10(-5) mol/l) and relaxation to acetylcholine (ACh, 10(-9)-10(-5) mol/l) were also recorded. Relaxation curves for levcromakalim, naringenin and ACh for the diabetic group were shifted to the right (p < 0.05) compared with the control. Contractions to phenylephrine were enhanced in the diabetic group (p < 0.01). SOD restored the ACh response but not those of K+ channel openers. On the other hand, apocynin restored the relaxation to naringenin but had no effect on both levcromakalim and ACh responses. The results suggest that both KATP and BKCa activities are attenuated in diabetes mellitus and that ROS appears to contribute only to the change in BKCa function.

Experimental malaria: the in vitro and in vivo blood pressure paradox

Objective

Malaria causes more deaths worldwide than any other parasitic disease. Many aspects of the biology that governs the pathogenesis of this parasite are still unclear. Therefore insight into the complexity of the pathogenesis of malaria is vital to understand the disease, particularly as it relates to blood pressure.

Methods

In vivo and in vitro experimental models were used for this study. In the in vivo study, mean arterial pressure, pulse rates and heart rates were recorded by cannulation of the carotid artery of rats. In the in vitro study, ring preparations of blood vessels from the rat aorta were studied using standard organ bath techniques. Dose–response curves for phenylepherine (PE)- and acetylcholine (Ach)-induced relaxation were constructed for rings pre-contracted with PE.

Results

Our results showed a significant (p < 0.05) reduction in the mean arterial pressure and pulse rates, while the heart rates remained unaltered in rats with malaria parasites, compared with the controls. Incubation of rat aortic rings with parasitised blood resulted in a significant (p < 0.05) increase in maximum contractile response to phenylephrine in the rat aortic rings but there was no effect on the baseline. The dose–response curve showed a significant (p < 0.05) leftward shift following the addition of parasitised blood and the EC₇₀ (M) values increased from 7 × 10^-7 to 5 × 10^-6 M. Following exposure to parasitised blood, the magnitude of Ach-induced relaxation responses reduced significantly (p < 0.05) from 73 ± 3.6 to 24.75 ± 7.25% in the rat aortic rings.

Conclusions

The results suggest that malaria parasitaemia caused in vivo reduction in blood pressure, and enhanced the responses to contractile agents and reduced relaxation responses to acetylcholine in vitro. This appears to be a paradox but is explainable by the complex cardiovascular control mechanisms in vivo. This may be independent of direct action on vascular smooth muscle.

Comparative analysis on the effect of palm oil (Elaeis guineensis) in reducing cadmium and lead accumulation in liver of Wistar rats

Context:

Palm oil from Elaeis guineensis is an edible nutrient substance with anti-inflammatory and antioxidant properties. We examined its protective effect against lead (Pb) and cadmium (Cd) accumulation in the liver.

Materials and Methods:

12% w/w of palm oil (PO) in rat chow concentrate was fed to rats exposed to Cd (200ppm) and Pb (100ppm) in drinking water at different feeding regimens. PO was administered either at the same time with the metals (group 2), post-treatment after exposure (group 3) or pre-treatment before exposure (group 4) for six weeks. The heavy metal accumulations in the liver were determined using AAS.

Results:

Weight losses induced by these metals were significantly (P<0.05) reversed by PO administration. Analysis among the groups showed that post-treatment group had a significant (P<0.05) higher percentage protection to Cd, but same time treatment for Pb (P<0.05) when compared with other groups. The protective ability to PO was only significantly (P<0.05) increased for Pb at week 2, but showed a time-dependent significant (P<0.05) increase for Cd across all treatment regimens.

Conclusion:

PO is beneficial in reducing metal accumulation in the liver and has a higher hepatoprotective effect to Cd compared to Pb at the selected doses by possibly affecting the processes of uptake, assimilation and elimination of these metals.

Comparative study on the hepatoprotection to heavy metals of Zingiber officinale

Context:

Zingiber officinale (Zingiberaceae) is a herb used for culinary and therapeutic purposes due to its anti-inflammatory and antioxidant potentials.

Objectives:

We examined its protective ability against mercury (Hg), lead (Pb) and cadmium (Cd) accumulation in the liver.

Materials & Methods:

Ground Zingiber officinale (7%, w/w of feed) was administered to rats either at the same time with the exposure ofheavy metals (group 2), a week after exposure to heavy metals (group 3) or given a week before heavy metal exposure (group 4) for six weeks. Animals were exposed to either of Hg (10 ppm), Cd (200 ppm) and Pb (100 ppm) in drinking water. The heavy metal accumulations in the liver were determined using AAS.

Results:

Weight losses induced by these metals were not reversed by Zingiber officinale administration. There was a significant (P<0.01) increase in protection to Pb (97%) and Cd (63%) accumulation when compared to Hg (32%) at week 2. The protective ability was significantly (P<0.01) decreased at week 4 when compared to week 2 for Cd and Pb but not to Hg in groups 3 (50%) and 4 (52%). At week 6, hepatoprotection to Hg (44%) and Cd (85%) was significantly (P<0.01) different but not to Pb which was only significant (P<0.05) in week 2 of treatment for all groups.

Discussion and Conclusion:

Zingiber officinale affected the bioavailability, elimination and uptake of these metals in a time-dependent way with highest beneficial reducing effect to Cd followed by Hg and least protection to Pb in the liver.

Possible mechanisms of action of the hypotensive effect of Annona muricata (soursop) in normotensive Sprague-Dawley rats

CONTEXT

Annona muricata Linn (Annonaceae) (soursop) is a food plant reported to have antihypertensive properties.

OBJECTIVE

We investigated the blood pressure reducing effect of its aqueous leaf extract and the possible mechanisms that may be responsible.

METHODS

Intravenous administration of an aqueous leaf extract (9.17-48.5 mg/kg) of A. muricata on the mean arterial pressure and heart rate were recorded invasively on anaesthetized, normotensive Sprague-Dawley rats. Contractile responses of rat aortic rings to the extract (0.5-4.0 mg/mL) were studied using standard organ bath techniques.

RESULTS

A. muricata (9.17-48.5 mg/kg) caused significant (p < 0.05) dose-dependent reduction in blood pressure without affecting the heart rates. The hypotensive effects were unaffected by atropine (2 mg/kg), mepyramine (5 mg/kg), propranolol (1 mg/kg) and L-NAME (5 mg/kg). A. muricata leaf aqueous extract significantly (p < 0.05) relaxed phenylephrine (10(-9)-10(-4) M) and 80 mM KCl induced contractions in endothelium intact and denuded aortic rings; and caused a significant (p < 0.05) rightward shift of the Ca(2+) dose response curves in Ca(2+)-free Kreb's solution containing 0.1 mM EGTA.

CONCLUSIONS

The hypotensive effects of A. muricata are not mediated through muscarinic, histaminergic, adrenergic and nitric oxide pathways, but through peripheral mechanisms involving antagonism of Ca(2+).

Possible mechanisms of action of the aqueous extract of Artocarpus altilis (breadfruit) leaves in producing hypotension in normotensive Sprague-Dawley rats

CONTEXT AND OBJECTIVES

Artocarpus altilis (Parkinson) Fosberg (Moraceae) (breadfruit) leaves are used as an antihypertensive remedy. We investigated the possible mechanisms of action of its aqueous extract and its effect on cytochromes P450 (CYP) enzyme activities.

MATERIALS AND METHODS

Intravenous administration of an aqueous leaf extract (20.88-146.18 mg/kg) of A. altilis on mean arterial pressure and heart rate were recorded via cannulation of the carotid artery on anaesthetized normotensive Sprague-Dawley rats. Recordings of the contractile activity of the aortic rings to the extract (0.71-4.26 mg/mL) were studied using standard organ bath techniques. Inhibitions of human CYP3A4 and CYP2D6 enzyme activities were evaluated by means of a fluorometric assay in 96 well plates using heterologously expressed microsomes.

RESULTS

A. altilis caused significant (p < 0.05) hypotensive and bradycardiac responses unaffected by atropine (2 mg/kg) and mepyramine (5 mg/kg), but attenuated by propranolol (1 mg/kg) and N(G)-nitro-L-arginine methyl ester (5 mg/kg). The extract (0.71-4.26 mg/mL) significantly (p < 0.05) relaxed phenylephrine (10⁻⁹-10⁻⁴ M) and 80 mM KCl-induced contractions in endothelium intact and denuded aortic rings; and caused a significant (p < 0.05) rightward shift of the Ca²⁺ dose-response curves in Ca²⁺-free Kreb's solution. Moderate inhibitions of cytochrome P450s (CYP3A4 and CYP2D6) enzyme activities with IC₅₀ values of 0.695 ± 0.187 and 0.512 ± 0.131 mg/mL, respectively, were produced.

CONCLUSION

A. altilis exhibits negative chronotropic and hypotensive effects through α-adrenoceptor and Ca²⁺ channel antagonism. Drug adversity effects are unlikely if the aqueous leaf extract is consumed with other medications reliant on CYP3A4 and CYP2D6 metabolism. This study thus provides scientific evidence for the use of the breadfruit in the treatment of hypertension.

Gastric ulceration in diabetes mellitus: protective role of vitamin C

The effect of vitamin C administration on gastric acid secretion and ulcer in diabetic rats was studied. Vitamin C (200 mg/kg b.w.) was administered to both streptozotocin-induced diabetic and control groups orally for 28 days. Gastric acid secretion was measured and ulcer was induced using ethanol. Histological changes were observed in the stomach. Basal and stimulated acid secretion in diabetic control rat was significantly (P < 0.01) decreased when compared to vitamin C-treated diabetic group and control. Administration of vitamin C significantly (P < 0.05) increased the histamine-stimulated gastric acid secretion in diabetics than control while reduction in gastric secretion by ranitidine was similar compared with control. Vitamin C treatment significantly (P < 0.05) reduced ulcer index in diabetic group and increased mucus weight when compared with diabetic group which was also confirmed with photomicrographs. The mean body weight of diabetic rats treated with vitamin C was comparable to the control. The blood glucose level was significantly (P < 0.01) reduced in diabetic group given vitamin C (8.9 ± 1.8 mMol/L) compared to the diabetic control (32.2 ± 2.1 g). It is concluded that vitamin C is beneficial in improving gastric acid secretion and protects against ulceration in streptozotocin-induced diabetes mellitus in rats due to its antioxidant potential.

Serum lipids, proteins and electrolyte profiles in rats following total body irradiation

OBJECTIVE

Serum lipid and electrolyte imbalances are common in critically ill patients undergoing radiation therapy. Although multiple disease states and medication may be responsible for the development of these disorders, the aim of this research is to sequentially document the effect of total body radiation on body function utilizing the sequential changes in the serum lipids, electrolytes and protein in rats.

METHODS

Serum protein and lipids contents were assessed using kits while electrolytes were assessed with flame photometry in rats exposed to total body irradiations of 1.27 Gy/min in cumulative doses to the fourth irradiation at five-day intervals.

RESULTS

Total cholesterol and triacylglycerols serum levels were significantly reduced by irradiation (p < 0.05). No significant differences between experimental and control groups for HDL-C serum levels were detected. Serum electrolyte concentration remained within the normal range after each total body irradiation. Sodium, bicarbonate and chloride were significantly (p < 0.05) higher than control while potassium and creatinine were significantly reduced after the first irradiation only. Sodium/potassium ratio was significantly (p < 0.05) elevated. Serum protein was significantly (p < 0.05) elevated with increasing radiation.

CONCLUSION

There are subtle but significant changes in serum lipids, electrolytes and protein after total body irradiation of normal rats. These variations could be due to non-specific stress reactions; as such, they are important markers in radiation induced injury diagnosis.

Antihypertensive properties of Allium sativum (garlic) on normotensive and two kidney one clip hypertensive rats

Allium sativum (garlic) is reported to act as an antihypertensive amidst an inconsistency of evidence. In this study, we investigated the cardiovascular effects of aqueous garlic extracts (AGE) on normotensive and hypertensive rats using the two-kidney one-clip (2K1C) model. Mean arterial blood pressure (MAP) and heart rate (HR) were measured in normotensive and 2K1C rat models anesthetized with thiopentone sodium (50 mg/kg body weight i.p.) through the left common carotid artery connected to a recording apparatus. The jugular vein was cannulated for administration of drugs. Intravenous injection of AGE (5-20 mg/kg) caused a significant (p<0.05) decrease in both MAP and HR in a dose-dependent manner in both the normotensive and 2K1C models, with more effects on normotensive than 2K1C rat model. The dose of 20mg/kg of AGE significantly (p<0.05) reduced systolic (16.7 ± 2.0%), diastolic (26.7 ± 5.2%), MAP (23.1 ± 3.6%) and HR (38.4 ± 4.3%) in normotensive rats. In 2K1C group, it significantly reduced systolic (22.2 ± 2.1 %), diastolic (30.6 ± 3.2%), MAP (28.2 ± 3.1%) and HR (45.2 ± 3.5%) from basal levels. Pulse pressure was significantly elevated (33.3 ±5.1%) in the 2K1C group. Pretreatment of the animals with muscarinic receptor antagonist, atropine (2 mg/kg, i.v.), did not affect the hypotensive and the negative chronotropic activities of the extract. AGE caused a decrease in blood pressure and bradycardia by direct mechanism not involving the cholinergic pathway in both normotensive and 2K1C rats, suggesting a likely involvement of peripheral mechanism for hypotension.

Estimation of absorbed cadmium in tissues of male and female albino rats through different routes of administration

The resultant effects of cadmium exposure are seen in almost all the systems of the body, however, this study is designed to quantify its accumulation in tissues of animals exposed to cadmium. The rats were divided into two distinct groups of males and females, which were then divided into three groups, each for the monitoring of exposure. Group 1 served as control male and female and received normal rat chow and tap water. Group 2 males and females were treated with 5 mg/kg body weight of cadmium chloride (Cd) intraperitoneally for eight days while Group 3 males and females rats received 100 ppm of Cd in drinking water for 18 days. The concentrations of cadmium were analyzed in tissues (lung, stomach, kidney, heart, spleen, blood) by AAS. There were significant (P<0.05) increase in Cd (ppm) accumulation in males compared with females lungs (2.253 ± 1.47 vs 0.317 ± 0.001), stomach (0.187 ± 0.094 vs 0.045 ± 0.032) and blood (0.070 ± 0.001 vs 0.001±0.001) when Cd was administered intraperitoneally. Following oral administration, there were significant (P<0.05) difference in Cd (ppm) content between males and females (kidney (0.506 ± 0.074 vs 0.748 ± 0.147), stomach (0.045 ± 0.020 vs 0.001± 0.001) and blood (1.126 ± 0.001 vs 0.114 ± 0.001). Our results suggest that Cd accumulation in the various organs was sex and route of exposure-dependent in rats.

Specificity of vascular reactivity and altered response in experimental malaria

OBJECTIVE

Adherence of erythrocytes infected with Plasmodium falciparum (P falciparum) to microvascular endothelial cells (sequestration) is considered to play an important role in parasite virulence and pathogenesis. In this study, we have examined the possibility that there is altered vascular reactivity due to the direct interaction between the parasitized erythrocytes and vascular endothelial cells and that it could be tissue specific.

METHOD

Ring preparations of blood vessels from the rabbit carotid and rat aorta were studied using standard organ bath techniques. Dose response curves for phenylephrine (PE) and acetylcholine (Ach)-induced relaxation were constructed in rings pre-contracted with PE.

RESULTS

Incubation of rat aortic rings with parasitized blood resulted in a significant (p < 0.05) increase in maximum contractile response to phenylephrine in the rat aortic rings but there was no effect on the rabbit carotid artery. The dose-response curve showed a significant (p < 0.05) left-ward shift following the addition of parasitized blood. Parasitised blood had no effect on baseline in both tissues. Following exposure to parasitized blood, the magnitude of Ach-induced relaxation responses reduced significantly (p < 0.05) in rat aortic rings and (p < 0.05) in rabbit carotid rings; relaxations to acetylcholine was more pronounced in the aortic compared to the carotid rings.

CONCLUSIONS

Malaria altered vascular reactivity through an endothelium-dependent mechanism. The regulation of vascular tone by various vasoactive agents following exposure to malaria parasites might be altered in a vessel-specific manner. This may contribute to or exacerbate the abnormal haemodynamics observed in the microcirculation of numerous vascular beds in malaria.

In vivo distribution of lead in male and female rats after intraperitoneal and oral administration

The resultant effects of lead exposure are seen in almost all the systems of the body and results in toxicity to many organs. Since toxicity depends on its degree of uptake, distribution and metabolism, the authors investigated the differential uptake, accumulation and distribution of lead in organs of males and female Wistar rats following various routes of administration. Group 1 served as control male and control female; group 2 males and females received 5 mg/kg body weight of lead intraperitoneally for 8 days while group 3 males and female rats were administered drinking water containing 100 ppm of lead acetate for 18 days. Tissues were collected for analysis of the lead content using atomic absorption spectroscopy. The relative retention of lead by the tissues was greater in rats exposed to lead by the i.p. route varying in the order of accumulation / uptake in males as lungs > spleen > stomach > kidney > blood > heart and in females as spleen > stomach > heart > kidney > blood > lungs (i.p. route) and (oral route) as for males kidney > lungs > stomach > blood > heart > spleen, and females as kidney > lungs > stomach > blood > heart > spleen. Male Wistar rats showed more accumulation with oral exposure in lungs, spleen and blood with values for kidney and stomach being significantly ( p < 0.05) higher when compared with females. Female Wistar rats showed more accumulation with i.p. exposure for spleen and stomach tissues while values for the heart was significantly ( p < 0.05) higher than the males. Our findings suggest that lead retention and the organ distribution varied depending upon the sex and route of lead administration.

Comparative study on the efficacy of Garcinia kola in reducing some heavy metal accumulation in liver of Wistar rats

Garcinia kola is regarded as an antidote and anti-hepatotoxic agent. We examined its protection ability against mercury (Hg), lead (Pb) and cadmium (Cd) accumulation in the liver. The ground seed was mixed with rat feed (5%, w/w) and fed to rats while Hg (10 ppm), Cd (200 ppm) and Pb (100 ppm) was given in drinking water. Garcinia kola was administered either at the same time with the metals (group 2), a week after exposure to heavy metals (group 3) or given a week before heavy metal exposure (group 4) for six weeks. The heavy metal accumulations in the liver were determined using AAS. Garcinia kola could not reverse the weight reduction in the heavy metal exposed groups although it offers more protection and aid greater elimination of heavy metals from the liver. There was a significant (P<0.01) increase in protection by Garcinia kola to Cd (72.4%) and Pb (56.2%) accumulation when compared to Hg (40%) at week 2 which was significantly (P<0.01) decreased at week 4 when compared to week 2. At week 6, the percentage protection to both Hg (64.2%) and Cd (62.2%) were comparable to each other while protection to Pb (49.9%) accumulation was significantly (P<0.01) reduced. The percentage protection was time-dependent in some groups but treatment during and after the exposure provided a greater protection. Garcinia kola has the highest hepatoprotective effect to Cd followed by Hg and least protection against Pb toxicity in rats and its administration is beneficial in reducing heavy metal accumulation in the liver.

Intestinal Fluid and Glucose Transport in Wistar Rats following Chronic Consumption of Fresh or Oxidised Palm Oil Diet

Chronic ingestion of thermoxidized palm oil causes functional derangement of various tissues. This study was therefore carried out to determine the effect of chronic ingestion of thermoxidized and fresh palm oil diets on intestinal fluid and glucose absorption in rats using the everted sac technique. Thirty Wistar rats were divided into three groups of 10 rats per group. The first group was the control and was fed on normal rat chow while the second (FPO) and third groups (TPO) were fed diet containing either fresh or thermoxidized palm oil (15% wt/wt) for 14 weeks. Villus height and crypt depth were measured. The gut fluid uptake and gut glucose uptake were significantly (P < .001) lower in the TPO group than those in the FPO and control groups, respectively. The villus height in the TPO was significantly (P < .01) lower than that in FPO and control. The villus depth in TPO was significantly (P < .05) higher than that in FPO and control groups, respectively. These results suggest that ingestion of thermoxidized palm oil and not fresh palm oil may lead to distortion in villus morphology with a concomitant malabsorption of fluid and glucose in rats due to its harmful free radicals.

Antispasmodic and spasmolytic effects of methanolic extract from seeds of Garcinia kola on isolated rat small intestine

The antispasmodic and spasmolytic effects of methanolic extract of seeds of Garcinia kola Heckel were studied on smooth muscle preparations in vitro. The influence of the extract on rat duodenum, jejunum and ileum was investigated using acetylcholine and barium chloride as agonists. The extract exhibited dose-dependent antispasmodic effects on contractions induced by acetylcholine, and dose-dependent spasmolytic effects on spasms induced by cumulatively increased concentrations of acetylcholine and barium chloride. The graded log concentration-response curves for acetylcholine were non-parallel but shifted to the right in the presence of the extract. It is concluded that the Garcinia kola extract inhibits smooth muscle activity via other mechanisms but not involving neither cholinergic nor adrenergic receptor interaction.

Intestinal motility and transit following chronic ingestion of different forms of palm oil diets

This study was aimed at finding the effect of palm oil diets on the small intestinal motor activity and transit in rats. Adult albino Wistar rats were divided into three groups of ten rats each. The first group was fed on rat chow containing 15% (wt/wt) of fresh palm oil diets for fifteen weeks. The second was fed on rat chow containing 15% (wt/wt) thermally oxidized diet while the third group was the control and so was fed on rat chow only. Water and feed were allowed freely to all the groups. Intestinal motility and transit were measured after the feeding period. Results show that there was a significant increase (P < 0.05) in basal tone of the ileum from rats fed on thermally oxidized palm oil diet when compared with fresh palm oil fed and control diets respectively. Contraction to acetylcholine (10(-11) - 10(-5)M) showed a biphasic tone with highest contraction at lower doses of acetylcholine and lowest tone at 10(-7)M in both fresh palm oil-fed and thermally oxidized oil-fed groups when compared with control. There was a significant (P < 0.05) attenuation of inhibition of atropine effect in the oxidized oil fed group when compared with control while there was a significant (P < 0.01) increase in transit of food material in the intestine of oxidized oil-fed group when compared with control and fresh palm oil-fed groups. These results show that chronic ingestion of oxidized palm oil diet causes an increase in basal tone of ileum and enhances intestinal motility and transit in the rat.

Stimulation of gastric acid secretion and intestinal motility by Vernonia amygdalina extract

Aqueous extract of Vernonia amygdalina infused intragastrically at a dose of 10 mg/ml to rats induced a significant increase in acid output which was reduced by, ranitidine (5 mg/kg b.w.) or atropine (1.2 microMol/kg b.w.). Moreover the extract evoked a dose-dependent contraction of the guinea pig ileum at a dose range of 0.6 mg/ml to 66 mg/ml which was inhibited by atropine (2.4 x 10(-8)-2.4 x 10(-6) M).

Effect of vitamin C on serum lipids and electrolyte profile of albino Wistar rats

The effect of oral administration of vitamin C on serum lipids and electrolyte profile were investigated in albino rats of the Wistar strain. Eighteen (18) albino rats of opposite sexes weighing between 150-300 g were used for the study and randomly assigned on the basis of body weight and litter origin to three study groups of six animals each. The control group received via oral route a placebo (4 ml of distilled water), while test groups 1 and II received 100 mg/kg body weight and 200 mg/kg body weight of vitamin C in 2.5 ml and 5.0 ml of the vehicle via gastric intubation respectively. The administration of vitamin C for 30 days produced a significant [P < 0.05] decrease in total cholesterol (TC), very low-density lipoprotein (VLDL) and low density lipoprotein (LDL) in the test groups versus control but there was no change in triglycerides (TG) and High density lipoprotein (HDL) levels. Computed HDL:LDL ratio also increased in the treatments relative to the control. Except for computed HDL:LDL ratio all the other changes were dose dependent and there was a slight non-significant increase in all electrolytes (Na(+), K(+); and HCO3(-) ions. The study confirms the hypocholesterolaemic effect of vitamin C and that Vitamin C has no adverse effect on serum electrolytes. It is suggested that its administration in moderate to high doses may protect against atherosclerosis and hypertension.

Vitamin C improves basal metabolic rate and lipid profile in alloxan-induced diabetes mellitus in rats

Diabetes mellitus (DM)is a multi-factorial disease which is characterized by hyperglycaemia, lipoprotein abnormalities and oxidative stress. This study evaluated effect of oral vitamin C administration on basal metabolic rate and lipid profile of alloxan-induced diabetic rats. Vitamin C was administered at 200 mg/kg body wt. by gavage for four weeks to diabetic rats after which the resting metabolic rate and plasma lipid profile was determined. The results showed that vitamin C administration significantly (p less than 0.01) reduced the resting metabolic rate in diabetic rats; and also lowered plasma triglyceride, total cholesterol and low-density lipoprotein cholesterol. These results suggest that the administration of vitamin C in this model of established diabetes mellitus might be beneficial for the restoration of basal metabolic rate and improvement of lipid profile. This may at least in part reduce the risk of cardiovascular events seen in diabetes mellitus.

Lung function status of workers exposed to wood dust in timber markets in Calabar, Nigeria

The effect of chronic exposure to dust from local woods such as ebony, achi, and iroko on lung function of timber market workers in Calabar - Nigeria, was studied. Forced vital capacity (FVC), Forced Expiratory Volume in one second, (FEV1), Forced Expiratory Volume as a percentage of forced vital capacity (FEV1 %), and Peak Expiratory Flow Rate (PEFR) were measured in 221 workers (aged 20-25 years) exposed to wood dust to assess their lung function and compared with 200 age- and sex- matched control subjects who were not exposed to any known air pollutant. The concentration of respirable dust was significantly higher in the test (P<0.001) than in control site. The mean values of FVC, FEV1, FEV1% and PEFR of the timber workers were significantly lower (P<0.01) than in control subjects. Respiratory symptoms such as cough, chest pain and nasal irritation had higher prevalence in the test group than in the control group. Non-respiratory symptoms (skin and eye irritation) were prevalent in the test group but not found in the control group. Workers exposed to wood dust had restrictive pattern of ventilatory function impairment. The lung function indices of the timber workers decreased with their length of service. Chronic exposure to wood dust impairs lung function.

Influence of palm oil (Elaesis guineensis) on health

In recent times there has been a growing research interest in palm oil, one of the major edible plant oils in the tropical countries, because of the link between dietary fats and coronary heart disease. Obtained from a tropical plant, Elaesis guineensis, it has a polyunsaturated fatty acid/saturated fatty acid ratio close to unity and a high amount of antioxidant vitamin A precursors and vitamin E. Palm oil is consumed in the fresh state and/or at various levels of oxidation. Feeding experiments in various animal species and humans have highlighted the beneficial role of fresh palm oil to health. These benefits include reduction in the risk of arterial thrombosis and atherosclerosis, inhibition of cholesterol biosynthesis and platelet aggregation, and reduction in blood pressure. However, a considerable amount of the commonly used palm oil is in the oxidized state which possesses potential dangers to the physiological and biochemical functions of the body. Oxidation is as a result of processing the oil for various culinary purposes. Studies have revealed that relative to fresh palm oil, oxidized palm oil induces an adverse plasma lipid profile, free fatty acids, phospholipids and cerebrosides. Additionally, oxidized palm oil induces reproductive toxicity and organotoxicity particularly of the kidneys, lungs, liver and heart. Available evidence suggests that at least part of the oxidized oil impact on health reflects generation of toxicants due to oxidation. The reduction of the dietary level of oxidized oil and/or the level of oxidation may reduce the health risk associated with consumption of oxidized fats.

Serum liver enzymes profile of Wistar rats following chronic consumption of fresh or oxidized palm oil diets

The effect of chronic consumption of palm oil diets on serum levels of some liver enzymes in rat was investigated. Two groups of rats were fed on either fresh or thermally oxidized palm oil, mixed at 15% level for 18 weeks and their effects on serum levels of alkaline phosphatase (EC 3.1.3.1), aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) enzymes were compared with a control group receiving normal rat feed. The levels of alkaline phosphatase (ALP) in the two groups were significantly higher (P < 0.05-0.01) than control. Mean ALP levels were significantly different in the two test groups (P < 0.05). Similarly, there was significant elevation (P < 0.05-0.01) of aspartate aminotransferase (AST) levels in oxidized oil-fed and fresh oil-fed groups when compared with the control. The mean alanine aminotransferase (ALT) level was significantly higher (P < 0.01) in the oxidized oil-fed group than the control and fresh oil-fed groups. The results indicate that chronic consumption of thermoxidized palm oil, with its accompanying hazardous free radicals, may be more injurious to liver cell integrity than fresh palm oil.

Altered responses of isolated aortic smooth muscle following chronic ingestion of palm oil diets in rats

The responsiveness of the rat aorta after chronic consumption of 15% (wt/wt) fresh and thermally oxidized palm oil diets was studied under standard organ bath procedures. Aortic rings from the oxidized oil-fed group showed significantly (P < 0.05) enhanced vascular responses to noradrenaline and potassium chloride when compared with the control and fresh palm oil-fed groups. The maximum tensions were 285.10 +/- 30 mg/mg tissue weight for the oxidized oil-fed group and 148.98 +/- 36 mg/mg for the control in response to noradrenaline. The fresh oil-fed group produced maximum tension of 133.9 +/- 20 mg/mg which was not significantly different from the control. The trend was similar with potassium chloride. The maximum tensions were 206.31 +/- 25 mg/mg for the oxidized oil-fed group and 93.33 +/- 13 mg/mg for the control group. The fresh oil-fed group produced maximum tension of 109.31 +/- 7.8 mg/mg which was not significantly different from the control. Relaxation to acetylcholine was significantly (P < 0.01) attenuated in the aortic rings obtained from the oxidized palm oil-fed group when compared with the control and fresh palm oil-fed groups. The percentage maximum relaxations to acetylcholine were 28.1 +/- 6.7% in the oxidized oil-fed group, 71.4 +/- 6.0% in control and 78.2 +/- 6.0% in the fresh oil-fed groups. The relaxation in the fresh oil-fed group was not significantly different from control. These results suggest that functional changes occur in rat blood vessels after chronic consumption of thermally oxidized palm oil.

Arterial pressure and lipid profile in rats following chronic ingestion of palm oil diets

The mean arterial blood pressure (MAP) and plasma lipid profile of rats following chronic consumption of a diet containing 15% palm oil (fresh or oxidized) were studied. Rats were allowed to feed on either a fresh or oxidized palm oil diet for 18 weeks and their effects were compared with a control group receiving normal rat feed. Mean arterial blood pressures were 128.0 +/- 2.3 mmHg (mean +/- SEM) for the control, 135.0 +/- 2.4 mmHg for the fresh-oil fed group and 147 +/- 2.5 mmHg for the oxidized oil-fed group. The oxidized oil-fed group had a significantly greater rise in mean arterial blood pressure than the control and fresh oil-fed groups (P < 0.01 and 0.05, respectively). Mean arterial blood pressure was not significantly elevated in the fresh oil-fed group than the control. Low density lipoprotein cholesterol (LDL) levels were 1.51 +/- 0.07 mMol/L for the control, 1.62 +/- 0.03 mMol/L for the fresh oil-fed group and 1.78 +/- 0.03 mMol/L for the oxidized oil-fed group. The values were not significantly different in the control and the fresh oil groups. LDL level was significantly higher in the oxidized than in the control (P < 0.01) and fresh oil-fed groups (P < 0.05). Total cholesterol for the two test groups were significantly (P < 0.05) higher than the control, while the value in the oxidized oil group was also significantly (P < 0.05) higher than the fresh oil-fed group. There was no significant difference in high density lipoprotein cholesterol (HDLP) levels in the three groups. The significantly elevated MAP in the oxidized oil-fed rats when compared to the fresh oil-fed and control rats may be due to thermoxidation of the fresh oil that produced significantly higher levels of LDL and total cholesterol which predisposes to high blood pressure.