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C Shigeno

Publications and source records attributed to C Shigeno.

At least 73 records · Page 4Linked to original sources
PubMed1982

[Studies on the measurement of vitamin D derivatives in human plasma. III. Plasma concentrations of vitamin D derivatives in various diseases (author's transl)].

Plasma concentrations of vitamin D3, 25-OH-D3, 24, 25(OH)2D3 and 1, 25(OH)2D3 were measured in patients with various diseases using the multiple assay system previously reported. In patients with hyperparathyroidism, the plasma levels of 1, 25(OH)2D3 tended to increase, while the levels of 24, 25(OH)2D3 tended to decrease in many cases. On the other hand, plasma 1, 25(OH)2D3 levels were low, while 24, 25(OH)2D3 levels were high in patients with hypoparathyroidism. No significant differences in the levels of plasma D3 derivatives among idiopathic-, postoperative- and pseudo- hypoparathyroidism were observed. In a majority of hemodialyzed patients with advanced renal failure who showed no overt bone changes on X-ray films, both the plasma 1, 25(OH)2D3 and 24, 25(OPH)2D3 levels were distributed from normal to very low. In a majority of patients with osteoporosis and hypoparathyroidism, plasma 1, 25(OH)2D3 levels rose quickly after the administration of 1 alpha-OH-D3. In hypophosphatemic vitamin D resistant rickets, however, the response to the relatively large amounts of 1 alpha-OH-D2 was poor, although the concentrations of plasma 24, 25(OH)2D3 were elevated by the 1 alpha-OH-D3 administration in most of these cases. The plasma 1, 25(OH)2D3 and 24, 25(OH)2D3 concentrations in patients with senile osteoporosis were distributed from lower to higher range than those of normal adults. There was a relatively good correlation between plasma levels of 25-OH-D3 and D3 only in cases with plasma D3 levels higher than 5 ng/ml. In addition, a hyperbolic regression curve was obtained between the plasma D3 and 25-OH-D3 ratio. These results may indicate that a possible negative feedback homeostatic mechanism exists between plasma levels of D3 and 25-OH-D3, but only with low plasma levels of D3.

Calcitriol↗
PubMed1982

Bone scintigraphy in pulmonary alveolar microlithiasis: a comparative study of radioactivity and density distribution.

A histologically proven case of pulmonary alveolar microlithiasis that demonstrated intense lung uptake of Tc-99m-MDP on a bone scan is presented. The spatial distribution within the lungs of the radioactivity and density was assessed either by single photon emission computed tomography (SPECT), or x-ray computed tomography (CT) respectively, and the regional magnitude of the two parameters were compared. The quantitative study of regional radioactivity and density revealed that both the parameters distributed symmetrically, showing gradual increase in magnitude from the upper to the lower lung regions. The radioactivity-density association observed in our patient may indicate on-going formation of microcalculi throughout the lungs, the degree of which is greater at the sites of more severe involvement.

Bone and Bones↗
PubMed1981

[Studies on the measurement of vitamin D derivatives in human plasma. I. A competitive protein binding assay for 25-hydroxyvitamin D in plasma (author's transl)].

A simple and precise method has been developed for the determination of 25-hydroxyvitamin D in 1 ml of human plasma. The method consists of methanol/chloroform extraction, purification by high pressure liquid chromatography and a competitive protein binding assay using vitamin D deficient rat serum. The ethanol extract from vitamin D deficient chick serum was added to the sample before CPBA to eliminate the non-specific interference in the CPBA system as a vitamin D free serum extract. The assay was sensitive to 0.72 ng/ml of plasma. Satisfactory results were obtained in the dilution and recovery tests. The coefficients of variation were 5.8 approximately 9.1% for the within-assay, and 7.4 approximately 10.3% for the between-assay. Plasma concentrations of 25-hydroxyvitamin D in 46 samples of normal human plasma were 21 +/- 10.5 ng/ml (mean +/- SD), and the seasonal variation was demonstrated. Plasma levels for 25-hydroxyvitamin D were high in patients receiving vitamin D2 and low in patients suffering from liver cirrhosis.

25-Hydroxyvitamin D 2↗
PubMed1981

Adenylate cyclase activation and competitive binding with renal tissue using synthetic eel calcitonin analog and its fragments.

The structure-function relationship of calcitonin (CT) was investigated using a synthetic eel CT (E-CT) analog and its fragments. Adenylate cyclase activation and competitive binding to rat renal receptors were used as parameters of function. [Asu1,7]E-CT analog, synthesized by replacing the S-S bond of Cys1-Cys7 in the natural hormone with ethylene linkage of 1-amino suberic acid (Asu), and E-CT fragment 11-32 had about 1/5th and 1/50th the potencies of synthetic E-CT, respectively, in both adenylate cyclase activation and competitive inhibition of 125I-labeled [Asu1,7]iodo-E-CT binding on rat renal plasma membranes. The minimal chain length required to activate adenylate cyclase in rat renal plasma membranes was between 12-18 amino acids, and the minimal chain length required to affect the CT receptor binding was between 6-12 amino acids, near the C-terminus. Fragments, including the C-terminus, show a disproportionate and potent inhibition of the binding compared with the potency required for adenylate cyclase activation. Thus, the amino acid sequence near the C-terminus probably plays an important role in the binding of CT to the receptor. (Endocrinology 108: 698, 1981.)

Adenylyl Cyclases↗