[Parathyroid hormone and calcium metabolism].
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Biomedical subjects
Publications and source records attributed to H Morii.
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1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) is known to be involved in regulating the proliferation of parathyroid cells and PTH synthesis through reactions involving its nuclear receptor. We evaluated the effects of 1,25-(OH)2D3 and its hexafluorinated analog, 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 (26,27-F6-1,25-(OH)2D3), on parathyroid cells. The 1,25-(OH)2D3 and 26,27-F6-1,25-(OH)2D3 each inhibited [3H]thymidine incorporation and ornithine decarboxylase (ODC) activity, which is important in cell proliferation, in primary cultured bovine parathyroid cells. The inhibitory effect of 26,27-F6-1,25-(OH)2D3 on PTH secretion from parathyroid cells was significantly more potent than that of 1,25-(OH)2D3 between 10(-11) M and 10(-8) M. Study of 26,27-F6-1,25-(OH)2D3 metabolism in parathyroid cells in vitro elucidated its slower degradation than that of 1,25-(OH)2D3. After 48 h of incubation with [1beta-3H]26,27-F6-1,25-(OH)2D3, two HPLC peaks, one for [1beta-3H]26,27-F6-1,25-(OH)2D3, and a second larger peak for [1beta-3H]26,27-F6-1,23(S),25-(OH)3D3, were detected. No metabolites were detected after the same period of incubation with 1,25-(OH)2[26,27-3H]D3. We observed that 26,27-F6-1,23(S),25-(OH)3D3 was as potent as 1,25-(OH)2D3 in inhibiting the proliferation of parathyroid cells. Data suggest that the greater biological activity of 26,27-F6-1,25-(OH)2D3 is explained by its slower metabolisms and by the retention of the biological potency of 26,27-F6-1,25-(OH)2D3 even after 23(S)-hydroxylation.
We describe a rare case of primary cardiac lymphoma associated with complete atrioventricular block, with recovery following systemic chemotherapy. A 61 year-old woman was admitted because of a massive pericardial effusion and complete atrioventricular block. Echocardiography disclosed several polypoid masses in the right atrium. A diagnosis of primary cardiac lymphoma was made. After three cycles of chemotherapy, the patient achieved a complete remission, the ECG showed first-degree atrioventricular block, and echocardiography revealed disappearance of the right atrial masses. This is the first report of a patient recovering from primary cardiac lymphoma and complete atrioventricular block following systemic chemotherapy. We conclude that aggressive treatment of this malignancy can improve cardiac function and the patient's prognosis.
Etidronate 200 mg daily was administered to four female patients with periodontitis and resultant alveolar pyorrhoea for periods of 2 weeks, followed by off-periods of 10 weeks or more, for 2-3 years. The macroscopic appearance of gingival mobility of the teeth, depth of periodontal pockets, and X-ray findings of alveolar bones improved markedly during this time. The effects were first observed after 6-12 months of treatment. These findings indicate that bisphosphonates may be effective in the treatment of periodontitis and resultant alveolar pyorrhoea. The effect may be mediated by the inhibitory action on bone resorption and the anti-inflammatory action of etidronate. Concomitant conventional dental management is also required.
Four women with periodontitis received intermittent cyclical etidronate (etidronate administered orally at a dose of 200 mg/day for 2 weeks, at intervals of 10-12 weeks or 6 months) for 4-5 years in addition to ordinary dental therapy. Alveolar bone density was measured using a new method comparing the percentage increase in density. Mean alveolar bone density increased significantly during intermittent cyclical etidronate treatment. Significant reductions were observed in the mobility of the teeth and the depth of periodontal pockets. There were significant correlations between alveolar bone density and both mobility of the teeth and the depth of the alveolar pockets. It is concluded that increases in alveolar bone density are associated with the clinical benefits of etidronate in the treatment of periodontitis.
Prostaglandin (PG) D2 and PGE2 receptor binding activities are regulated in various fashions. The protein phosphorylation by exogenous cAMP-dependent protein kinase or calmodulin-dependent protein kinase II significantly increased PGE2 binding activity through an increase in the apparent amount of the maximal binding, suggesting that the PGE2 receptor may be regulated through protein phosphorylation-dephosphorylation. Other possible regulatory mechanisms were found as the result of studies on functional modification of glycoconjugates. Pretreatment with glycoprotein-specific endoglycosidases (peptide N-glycohydrolase F, endo-alpha-N-acetylgalactosaminidase) decreased both PGD2 and PGE2 receptor binding activities and consequently these activities became nonspecific ones. In addition, these binding activities were increased by the addition of a ganglioside or cerebroside mixture, but not ceramide. The addition of separate purified glycolipids showed more specifically their effect on each PG binding. PGD2 binding activity was increased by GD1a and GQ1b and decreased by GM1 and GT1a, while PGE2 binding activity was increased by GQ1b and galactocerebroside. In such a way, PG receptors may require some specific microenvironment for their maximal binding activity.
We investigated whether the presence of diabetes mellitus (DM) was related to the severity of the anemia observed in patients with renal failure who were not receiving dialysis. Forty patients were examined, (19 with long-term type II DM (DM-CRF), 21 with renal failure due to other causes (non-DM-CRF)). The two groups did not differ significantly as to age, sex, serum creatinine or erythropoietin. Hemoglobin was significantly (p < 0.005) lower in the DM-CRF patients (9.5 +/- 2.1 g/dl) than in the non-DM-CRF patients (11.2 +/- 2.0 g/dl). Multiple regression analysis indicated that higher serum creatinine levels and the presence of DM were independent risk factors for anemia (R2 = 0.494, p < 0.001). DM appeared to be a risk factor for the severity of anemia in patients with renal failure who were not receiving dialysis.