[Show abstract][Hide abstract] ABSTRACT: We have investigated how the endothelium affects vascular responses following sub-chronic low dose cyanide administration. Cyanide exists in low levels in cassava foods, which are widely consumed in tropical Africa. Adult rabbits were administered 0.38 mg/kg per day KCN po for 25 days, and responses of the isolated aortic rings to noradrenaline (NA), calcium chloride (Ca2+) and acetylcholine (ACh) were measured in vitro in the presence and absence of the endothelium. In order to establish that the dose was not toxic, animal weight, some haematological indices, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured. Results show that endothelium denudation significantly (P <0.05) attenuates NA-induced contraction in rings from cyanide-treated rabbits. There was a similar reduction in response in Ca2+-depleted NA-precontracted endothelium-denuded aortic rings from cyanide-treated rabbits. Endothelium-denuded rings from cyanide-treated rabbits showed significantly (P <0.05) enhanced relaxation to ACh. In rings from control animals, the responses to NA and Ca2+ were not significantly altered, whether in the presence or absence of the endothelium. There were no significant changes in the studied toxicological indices. We conclude that endothelial compromise is necessary for low-dose sub-chronic cyanide-induced to alter vascular reactivity to NA and ACh.
Human & Experimental Toxicology 03/2007; 26(2):105-10. · 1.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Water samples of 72 rivers, streams and waterways in Southern Nigeria were carefully collected and the following physico-chemical analyses subjected on the samples. Temperature, colour, taste, turbidity, pH, total dissolved solids (TDS), conductivity and heavy metal profiles (Pb, Cr, Cd, Fe, Zn, Mn, Cu) were assessed among the entire samples collected. The turbidity (NTU) of 93% of all the samples was higher than World Health Organisation (WHO) and European Economic Community (EEC) standards. 57% of the entire samples had conductivities above normal limits. The pH of 81% of the entire samples also were above WHO and EEC guide limits. Profiles of the heavy metals showed Pb, Cd, Cr, Zn and Mn levels in some of the samples being above the guidelines of WHO and EEC. Fe had 55% of all the samples exceeding recommended standard of 0.20 ppm; Cr had 15% exceeding the recommended 0.05 ppm, Cd had 11% exceeding 0.003 ppm while 7% of both Zn and Pb exceeded 3 ppm and 0.10ppm respectively. These results indicate that heavy metal pollution and toxicity might pose serious risks to the health of communities residing around and using these surface waters for domestic, commercial and socio-cultural purposes.
African Journal of Biotechnology (ISSN: 1684-5315) Vol 6 Num 5. 01/2007;
[Show abstract][Hide abstract] ABSTRACT: Some conventional and non-conventional sources of drinking water in Nigeria were screened for Fe, Zn, Cu, Mn, cyanide, nitrate, nitrite, nitrosamines, total coliform, E. coli and fecal streptococci, using standard analytical methods. Results obtained showed that water samples from overhead tanks and those from rivers in industrialized areas had iron levels far in excess of WHO permissible concentrations; while in all samples, Cu, Mn and Zn were within safe limits. There was a wide range (42.2 to 179.8) in % coefficient of variation, CV of the minerals between samples, suggesting that sample source influenced mineral levels. The range of values for nitrate, nitrite and nitrosamines were 83�32 to 21,720�590, 14.5�5.0 to 52.0�14.0 and 0.10�0.01 to 0.56�0.03 g L <sup>1</sup>, respectively. Surface and overhead tanks had nitrate levels twice the US EPA recommended maximum contaminant limits. The %CV values for nitrate, nitrite and nitrosamines were 157.0, 49.5 and 13.0%, respectively, implying locational variability in these parameters. Cyanide was not detected in any of the samples. Fecal contamination of all samples was indicated by presence of fecal coliform (range 3 to 1,100 cells/100 mL) and fecal streptococci (range 3 to 240 cells/100 mL). The public health significance of these results underscore the need for adequate disposal of human and industrial wastes and the importance of regular monitoring of all drinking water sources.
[Show abstract][Hide abstract] ABSTRACT: The effect of antioxidant vitamin (AOV) administration on cyanide-induced ocular damage was investigated in New Zealand White rabbits maintained for 30 days on either pure growers mash or mash + 400ppm cyanide with or without oral AOVs. Cyanide caused significant decreases in superoxide dismutase, catalase and Na+-K+ ATPase; and significant increases in malondialdehyde levels in the lens (p < 0.05). AOVs reversed the elevation in malondialdehyde but had no effect on the enzymes. The results suggest that the damaging effects of oxidative stress imposed by cyanide on the lens can be mitigated by AOVs, probably through enhancement of its antioxidant status rather than directly reversing the inhibition of SOD and catalase. This underscores the need for AOV supplements especially by individuals routinely exposed to habitual, dietary and occupational cyanide.
Journal of Medicine and Biomedical Research (ISSN: 1596-6941) Vol 3 Num 1. 01/2004;
[Show abstract][Hide abstract] ABSTRACT: The effect of antioxidant vitamins on cyanide-induced tissue damage was investigated in New Zealand White rabbits using a combination of colorimetric, spectrophotometric, enzymatic, gravimetric and histological methods. Three groups of rabbits (six per group) were used in a 4-week feeding experiment. One group received pure grower's mash, while a second group was fed mash containing 400 ppm inorganic cyanide. The third group received daily oral doses of vitamins A, C and E, in addition to mash and 400 ppm cyanide. There were significant decreases (P < 0.05) in activities of superoxide dismutase (SOD), catalase and alkaline phosphatase (AP) in the liver, lung and kidney of the two groups given cyanide, but the decreases were significantly lower (P < 0.05) in the group fed antioxidant vitamins. In addition, the antioxidant vitamin supplementation led to marked reductions in the severity of histopathological degeneration in these tissues. These results strongly suggest that cyanide-induced tissue lesions may be relieved by adequate intake of antioxidant vitamin supplements.
Food and Chemical Toxicology 04/2003; 41(4):463-9. · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The histotoxic effects of chronic cyanide insult on heart, lung and pancreatic tissues, and some corroborative enzyme and metabolite changes were studied in New Zealand White rabbits using colorimetric, enzymatic and histochemical methods. Two groups of rabbits were fed for 10 months on either pure growers mash or grower mash +702 ppm inorganic cyanide. There were no significant differences in time-course profiles of serum amylase and fasting blood glucose between the cyanide-fed group and control. Pancreatic islet and heart histologies showed no pathological changes, and there were no significant differences in both serum and heart aspartate transaminase activities between the two groups. However, there were significant decreases (P<0.01) in alkaline phosphatase activity in the lungs of the cyanide-fed group, with corresponding significant (P<0.05) increases in the serum activity of the enzyme. Histological examination of lung tissue of the cyanide-treated rabbits revealed focal areas of pulmonary oedema and necrosis. These results suggest the existence of variabilities in tissue susceptibilities to the toxic effect of chronic cyanide exposure. It would appear that chronic cyanide exposure may not predispose to diabetes in the presence of adequate protein intake.
Food and Chemical Toxicology 06/2000; 38(6):543-8. · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bean pastes from the black eyed bean (Vigna unguiculata), pigeon pea (Cajanus cajan) and Ife brown (V. unguiculata) were processed into a popular West African snack moi-moi, cooked in open aluminium cups and in sealed, thin, transparent cellophane bags. The residual total, free and bound cyanide levels of moi-moi from both processes were determined using a combination of enzymatic and colorimetric procedures. Results showed that in all cases, cooking of moi-moi in open aluminium cups caused retention of significantly higher (P<0.05) residual free cyanide than cooking in sealed cellophane bags. Loss of bound cyanide was unaffected by cooking procedure. These results suggest that cooking of moi-moi in cellophane bags reduces the risks of cyanide exposure from legumes.
Food and Chemical Toxicology 08/1999; 37(7):741-3. · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effect of prolonged chronic cyanide exposure on liver and kidney integrity, as well as some associated enzyme and metabolite changes, were investigated in New Zealand white rabbits (initial mean weight 1.52 kg) using a combination of colorimetric, spectrophotometric, enzymatic, gravimetric and histological procedures. Two groups of rabbits were fed for 40 weeks on either pure growers' mash or growers' mash containing 702 ppm inorganic cyanide. Results obtained indicate that the cyanide-fed rabbits had significantly decreased liver activities of alkaline phosphatase, glutamate pyruvate transaminase and sorbitol dehydrogenase relative to controls (P<0.05). On the other hand, there were significant increases (P<0.05) in the serum activities of these enzymes in the cyanide-treated group. Kidney alkaline phosphatase activity was significantly decreased (P<0.05), while serum urea and creatinine were significantly higher (P<0.05) in the cyanide group relative to controls. The cyanide treatment led to significant increases in both tissue and serum activities of lactate dehydrogenase. In addition, liver and kidney rhodanese activities were significantly raised in the cyanide-fed group. There were marked degenerative changes in the liver and kidney sections from the cyanide-treated rabbits. These results suggest that chronic cyanide exposure may be deleterious to liver and kidney functions.
Food and Chemical Toxicology 08/1999; 37(7):745-50. · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Controlled fermentation of cassava tuber sections using a starter culture consisting of Citrobacter freundii, Geotrichum spp., Candida spp. and Saccharomyces spp. yielded the most acceptable product ‘akpu’, with respect to odour and residual cyanide (P < 0.05; P < 0.01 in some cases). Although traditional fermentation resulted in a significantly higher protein and lower HCN (P < 0.01) content than in all controlled fermentations, the product is significantly more odorous and lower in dietary fibre (P < 0.05).
[Show abstract][Hide abstract] ABSTRACT: The cyanide contents of seeds of varieties of Phaseolus aureus, Vigna unguculata, Cajanus cajan and Canavalia gladiatus were studied. Results obtained show total cyanide contents of 381–1093, 285–1223, and 208–953 mg kg−1 dry weight of intact seed, testa and cotyledons, respectively, with testa having 3–5 times higher HCN than cotyledons in some cases. Soaking of seeds in water for 24 h led to appreciable losses in HCN, while boiling for 3 h caused drastic reduction (49–95%) in HCN. After boiling for 3 h, innocuous HCN levels were obtained with seeds previously soaked in water for 24 h and divested of testa. Thus soaking of bean seeds in water and subsequent removal of testa prior to boiling will decrease HCN in bean meals.
[Show abstract][Hide abstract] ABSTRACT: Rauwolfia vomitoria (RV) Afzel (Apocynaceae) is a medicinal plant used in traditional medicinal practice for the treatment of hypertension. This research is devoted to phytochemical constituents, in particular, some specific alkaloids present in the RV root extract. The phytochemical evaluation revealed the presence of alkaloids, tannins, saponins, and flavonoids in this extract. The antioxidant activity of the RV root extract was also evaluated in a series of in vitro assays involving free radicals. The extract exhibited significant hydrogen peroxide scavenging effect relative to ascorbic acid (p < 0.05, IC50 = 98 μg/ml), nitric oxide scavenging effect (50.37 ± 0.4% after 150 min), and metal chelating activity (89.08 ± 2.62%). In addition, it exhibited significant ferric reducing power relative to ascorbic acid (p < 0.05). The total content of phenolic substances was 233.3 ± 2.9 mg/g. The extract was also studied for its inhibitory capacity on lipid peroxidation as a possible mechanism of its aphrodisiac effect, by measuring thiobarbituric acid reactive substances in various male-cow tissues incubated in a 5% solution of the RV root extract, distilled water, and antioxidant vitamins C and E upon keeping the samples frozen for 35 days. Tissues incubated in the test solution had lower levels of malondialdehyde (MDA) compared to those in the samples incubated in distilled water. Results obtained from this study indicate that the RV root extract can be a potential source of natural antioxidants.
[Show abstract][Hide abstract] ABSTRACT: The effect of cyanide toxicity on Ca2+-ATPase activities were significantly decreased in the lens and vitreous humour of the cyanide-fed rabbits (p< 0.05), while the corneal enzyme was unaffected. Ophthalmoscopic examination of the cyanide-exposed rabbits revealed adverse morphological changes, including pale fundus, low retinal reflex and lenticular opacification. The results suggest that cyanide-induced cataractogenesis may be a consequence of disruption of vitreous humour and lenticular calcium homeostasis.
Journal of Medicine and Biomedical Research (ISSN: 1596-6941) Vol 3 Num 1.
[Show abstract][Hide abstract] ABSTRACT: 1. Rhodanese activity has been determined in some organs of three species of lizards, namely: rainbow lizard, wall gecko and skink.2. While the activity was significantly higher in the livers of all the species compared to that in the kidney, small intestine and the brain, there were significant differences in the enzyme in the livers of the different species. The activity was highest in the liver of the rainbow lizard followed by that of wall gecko and then skink.3. The order of activity of the enzyme in the organs of the rainbow lizard was liver > kidney > small intestine > brain.4. The high level of rhodanese in lizard tissues suggests that the enzyme may be involved in roles other than cyanide detoxification.
Comparative Biochemistry and Physiology Part C: Comparative Pharmacology. 98:275-276.