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S Oshikawa

Publications and source records attributed to S Oshikawa.

5 recordsLinked to original sources
PubMed2000

Follow up of water use in a tin mining area affected with arsenic poisoning.

Ron Phibun district in southern Thailand has been known as an endemic area for arsenic contamination. The government has been trying to improve the situation by encouraging the use of rainwater and piped water. This study aimed to document the change of water use and to identify factors associated with safe water use in 1997 compared to that in 1994. Home visits and face-to-face questionnaire interviews were undertaken. Information on water use for drinking, cooking, washing food and washing utensils in 1994 and 1997 was obtained. Among 3,849 households from which data could be obtained (estimated 79% of total households), the percentages of using safe water (including water from bottled rain water, piped and artesian well water) for drinking and cooking rose from 72.5 and 57.9 in 1994 to 93.6 and 80.9 in 1997, respectively. The percentages for washing foods and for washing utensils rose from 28.6 and 20.5 to 59.1 and 53.8, respectively. In 1997, percentage of households using piped water for drinking and cooking was still low (3.6 and 12.3) compared to those using piped water for washing food and utensils (39.1 and 43.6). Multivariate analysis shows that independent factors of the household predicting safe water use are: high arsenic area, near main road and having piped water installed. The influence of these factors (as judged by the level of odds ratio) operates more or less equally on water use for all purposes, except that installation of piped water has more influence on washing water than drinking and cooking water. We conclude that safe water supply in the area is still inadequate. Even if piped water is installed, it is often not used for drinking and cooking. The reasons for not using piped water for drinking and cooking need to be identified.

Arsenic Poisoning↗
PubMed1997

Effects of delayed treatment with nebracetam on neurotransmitters in brain regions after microsphere embolism in rats.

1. The effects of delayed treatment with nebracetam, a novel nootropic drug, on neurotransmitters of brain regions were examined in rats with microsphere embolism-induced cerebral ischaemia. 2. Cerebral ischaemia was induced by administration of 900 microspheres (48 microns) into the internal carotid artery. The rats with stroke-like symptoms were treated p.o. with 30 mg kg-1 nebracetam twice daily. The levels of acetylcholine, dopamine, noradrenaline, 5-hydroxytryptamine (5-HT) and their metabolites in the cerebral cortex, striatum and hippocampus of animals with microsphere embolism were determined by high performance liquid chromatography (h.p.l.c.) on the 3rd and 7th days after the operation. 3. Although the microsphere embolism induced significant changes in most of the neurotransmitters and some of their metabolites in the brain regions, the delayed treatment with nebracetam partially restored only the hippocampal 5-HT and the striatal dopamine metabolite contents on the 3rd day. 4. The hippocampal in vivo 5-HT synthesis, but not the striatal dopamine synthesis, was attenuated in rats with microsphere embolism on the 3rd day, but was restored by treatment with nebracetam. In vivo striatal dopamine turnover rate of the rats with microsphere embolism was inhibited on the 3rd day irrespective of treatment with nebracetam. 5. The present study provides evidence for a possible action of nebracetam on 5-HT metabolism in the ischaemic brain.

Acetylcholine↗
PubMed1997

Effects of nebracetam on synaptosomal monoamine uptake of striatal and hippocampal regions in rats.

Effects of nebracetam, a novel nootorpic agent, on the synaptosomal uptake of neurotransmitter monoamines of the brain regions were examined. Striatal and hippocampal synaptosomes were isolated by the Percoll gradient method, and the striatal dopamine uptake and hippocampal serotonin uptake were measured in the presence of different concentrations (1 to 1000 microM) of nebracetam in vitro. A significant reduction in dopamine uptake in the striatum and serotonin uptake in the hippocampus was seen at concentrations of 100 microM or above. In in vivo microdialysis study, there were no appreciable changes in the extracellular concentrations of striatal dopamine and hippocampal serotonin when this agent at a dose of 30 mg/kg, which was effective in improving ischemic brain energy metabolism, was applied i.p. to the rat. The ineffectiveness of nebracetam in the in vivo microdialysis may be due to low levels of the concentration of nebracetam when the agent was administered i.p. at a dose of 30 mg/kg, since the brain blood concentration of this agent is pharmacokinetically estimated to be no more than 15 microM when this dose of nebracetam is employed. Thus, it is unlikely that this agent at a pharmacologically effective dose alters dopamine or serotonin uptake in the brain nerve terminal under normal conditions.

Animals↗
PubMedDate not supplied

Beneficial effect on nebracetam on energy metabolism after microsphere-induced embolism in rat brain.

The present study was undertaken to examine the possible therapeutic effects on nebracetam on the energy metabolism of rat brain regions in microsphere-induced, sustained ischemia. Microsphere embolism was induced by injection of 900 microspheres (48 microns in diameter) into the right internal carotid artery of rats, and changes in the energy metabolism of the cerebral cortex, striatum and hippocampus of the right hemisphere were determined without and with nebracetam treatment. Microsphere embolism induced increases in lactate and glucose contents and decreases of ATP and creatine phosphate contents in these regions, suggesting that sustained impairment of cerebral energy metabolism occurred. These changes were gradually reversed with time after the operation. Treatment of microsphere-injected rats with 30 mg/kg of nebracetam, p.o., twice a day, was started one day after the onset of cerebral ischemia. The effects of treatment with nebracetam on cerebral energy metabolites were determined on the 3rd and 7th day after operation. Treatment of microsphere-injected rats with nebracetam significantly improved these variables on the 3rd day after the onset of ischemia, but the improvement was small on the 7th day, except for reversal of the hippocampal ATP content. These results suggest that nebracetam is a possible therapeutic agent for the restoration of cerebral energy metabolism against microsphere-induced, sustained cerebral ischemia.

Adenosine Triphosphate↗