Investigations on the effect of the local structures on Fe-ZSM-5 zeolites by means of ESR, UV–Vis absorption and XRD measurements have shown that Fe-ZSM-5 with low Si/Al ratios includes highly dispersed Fe-oxides with tetrahedral and distorted tetrahedral coordinations, while the latter species could not be observed in Fe-ZSM-5 with high Si/Al ratios. Moreover, the photocatalytic decomposition of N2O into N2 and O2 was found to proceed on Fe-ZSM-5 having low Si/Al ratios with a good linearity against the UV-irradiation time and a good stoichiometry. It was also observed that the photocatalytic efficiency decreased when the Si/Al ratio was increased. These results clearly suggest that a highly dispersed distorted tetrahedrally coordinated Fe-oxide species plays a significant role in the photocatalytic decomposition of N2O into N2 and O2.
The study results indicated that raloxifene can transiently reduce the levels of bone metabolism markers and might be useful for preventing fractures in postmenopausal women with end-stage renal failure, although raloxifene use over the long term may not have adequate efficacy in the absence of appropriate concomitant active vitamin D therapy.
In June 2003, sevelamer hydrochloride became widely available in Japan and was expected to control hyperphosphatemia in hemodialysis patients without inducing hypercalcemia. To evaluate the impact of sevelamer therapy on mineral metabolism, we recruited 954 hemodialysis patients from 21 renal units just before the general release of sevelamer in Japan. The serum calcium, phosphate, and parathyroid hormone levels determined on enrollment were compared with those later measured in June 2004. Sevelamer was prescribed for 169 of the 859 patients for whom data were available in 2004. The mean calcium level, phosphate level, and calcium x phosphate product were all significantly reduced during the 12-month study period, but the intact parathyroid hormone (iPTH) level did not change. As a result, the percentage of patients who achieved a calcium x phosphate product of <55 mg(2)/dL(2) was significantly increased, but there were no changes in that of patients who achieved the target ranges for phosphate (3.5-5.5 mg/dL) or iPTH (150-300 pg/mL). Among sevelamer-treated patients, iPTH significantly increased, and this change was more marked in the patients with an initial iPTH level <150 pg/mL. Sevelamer was useful for reducing the serum calcium level and calcium x phosphate product, but hyperphosphatemia and hyperparathyroidism were not improved in our study population at 12 months after the release of sevelamer. A decrease in the calcium load might result in the exacerbation of hyperparathyroidism. However, among patients with relative hypoparathyroidism, sevelamer therapy may be beneficial for the prevention of adynamic bone disease.
Key words:sevelamer hydrochloride, bone alkaline phosphatase, bone-specific tartrate-resistant acid phosphatase, hypoparathyroidism, hemodialysis 〈Abstract〉 Sevelamer hydrochloride has been administered to control hyperphosphatemia without calcium load. In this study, we investigated the effects of attenuation of calcium load by sevelamer hydrochloride on bone metabolic / markers in 46 hemodialysis patients with serum intact parathyroid hormone(iPTH)levels<150 pg/mL. After replacement of calcium carbonate with sevelamer, their serum calcium levels decreased. The iPTH levels increased after 4 weeks and the magnitude of the increase was highly correlated with the extent of decrease in
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