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Summary: This study measured haematological and liver function parameters in workers occupationally exposed to cement dust in order to test the hypothesis that cement dust exposure may perturb these functions. Assessment of haematological parameters and liver function were performed in 23 workers occupationally exposed to cement dust (mean years of exposure = 9.6± 1.5 years) and 46 matched unexposed controls. The haemoglobin concentration (P< 0.001) and packed cell volume (P< 0.02) of exposed workers were significantly lower and the platelet (P<0.01) and white cell counts (P< 0.05) were significantly higher than in the unexposed workers. There was no significant difference in the total granulocyte and lymphocyte/monocyte counts. The liver function parameters remained similar in the exposed workers compared to the unexposed except serum aspartate aminotransferase and alkaline phosphatase activities which were significantly lower (P<0.05). These results suggest that occupational exposure to cement dust may perturb haemopoietic function while preserving liver function.

ABSTRACT

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The relaxant effects of an aqueous extract of the leaf of plant cassia occidentalis (C.O.)

Viscum album leaf extract has a folk reputation as an antihypertensive agent in Nigeria. Evidence suggests that it has a relaxant effect on smooth muscle. The present study was designed to investigate the role of calcium in the vasorelaxant effect of this extract. Concentration response studies to noradrenaline, KCl and CaCl 2 were carried out in rat aortic rings with and without the extract in physiological salt solution (n=6 each). Also the role of intracellular calcium mobilisation was studied by measuring the phasic response to noradrenaline in Ca 2+-free EGTA physiological salt solution (n=6). The contractile responses to noradrenaline or KCl were attenuated (P<0.05) and shifted to the right in the presence of the extract. Also the contractile response to CaCl 2 in the presence of noradrenaline or KCl was attenuated (P<0.05) and shifted to the right, while the phasic response to noradrenaline was significantly (P<0.05) diminished These results suggest that the vasorelaxant effect of Viscum album extract may be mediated by a non-specific non-competitive inhibition of Ca 2+ influx as well as inhibition of Ca 2+ mobilization from intracellular stores. This implies that it may contain vasorelaxant agents that may have calcium antagonistic potential.

Metabolic syndrome is linked to the consumption of fructose-rich diets. Nutritional and pharmacological interventions perinatally can cause epigenetic changes that programme an individual to predispose or protect them from the development of metabolic diseases later. Hibiscus sabdariffa (HS) reportedly has anti-obesity and hypocholesterolaemic properties in adults. We investigated the impact of neonatal intake of HS on the programming of metabolism by fructose. A total of 85 4-day-old Sprague Dawley rats were divided randomly into three groups. The control group (n=27, 12 males, 15 females) received distilled water at 10 ml/kg body weight. The other groups received either 50 mg/kg (n=30, 13 males, 17 females) or 500 mg/kg (n=28, 11 males, 17 females) of an HS aqueous calyx extract orally till postnatal day (PND) 14. There was no intervention from PND 14 to PND 21 when the pups were weaned. The rats in each group were then divided into two groups; one continued on a normal diet and the other received fructose (20% w/v) in their drinking water for 30 days. The female rats that were administered with HS aqueous calyx extract as neonates were protected against fructose-induced hypertriglyceridaemia and increased liver lipid deposition. The early administration of HS resulted in a significant (P⩽0.05) increase in plasma cholesterol concentrations with or without a secondary fructose insult. In males, HS prevented the development of fructose-induced hypercholesterolaemia. The potential beneficial and detrimental effects of neonatal HS administration on the programming of metabolism in rats need to be considered in the long-term well-being of children.

To study the effect of anti-sickling drugs on cellular dehydration induced by entry of Ca, sickle cells were subjected to cyclical oxygenation-deoxygenation for 15 h in Ca-containing buffer. The consequential loss of cation (K) via the Ca-dependent K efflux (Gardos) channel caused cell dehydration and loss of deformability. Inhibition of a specific fraction of Ca entry by verapamil had no rheologically protective effect, whereas inhibition of the Gardos channel by clotrimazole or nitrendipine had a marked protective effect. When Gardos channel inhibition (by either clotrimazole or nitrendipine) was combined with stabilization of the oxy-conformation of sickle haemoglobin (by the substituted benzaldehyde 12C79), an additive protective rheological effect was achieved with 60-78% reduction in clogging rate of 5 microns diameter pores when compared with no drug. Therapeutic use of anti-sickling compounds in combination may achieve increased efficacy with lower toxicity.