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Biomedical subjects

K Miyai

Publications and source records attributed to K Miyai.

At least 307 records · Page 17Linked to original sources
PubMed1981

Nature of bile acid maximum secretory rate in the rat.

We studied the determinants of maximum bile acid secretory rate (SRm) in the rat. The choledochocaval fistula rat model manifested a bile acid secretory rate far in excess of the SRm previously reported for taurocholate in this species. We studied the ability of various bile acid solutions to maintain the high secretion rate in this model. Whole-rat bile, but not taurocholate in 2% albumin nor rat bile with bile acid content over 90% taurocholate, maintained secretion rate. We concluded that the mixture of bile acids in rat bile was the most important determinant of the high secretion rate and that the high rate was not due to a peculiarity of the model itself nor to the infusion of biliary lipids together with bile acids. Conventional determination of the SRm in the bile fistula rat confirmed this impression, with the least toxic bile acids manifesting the highest SRm. During infusion of taurocholate beyond the SRm, bile flow and bile acid secretion rate fell. This was accompanied only by scattered focal necrosis of single liver cells or of small aggregates of cells and not by any diffuse subcellular morphological change. We believe the maximum bile acid secretory rate is determined by toxicity of a specific bile acid for the secretory mechanism rather than by a limitation in transport receptor number as is usual with substances manifesting classical transport maxima. The high SRm of the 7 beta-hydroxy bile acid, ursodeoxycholic acid, is probably related to its very low toxicity. The high SRm in the choledochocaval fistula rat is probably related to the presence of 7 beta-hydroxy muricholic acids in the bile of this species.

Animals↗
PubMed1981

Elevated levels of circulating carcinoembryonic antigen in hypothyroidism.

The level of circulating carcinoembryonic antigen (CEA) was measured in 148 patients with various thyroid diseases. A significantly high frequency of positive CEA was observed in hypothyroid patients with Hashimoto's disease, but the serum CEA levels were not correlated with the serum calcitonin concentrations in Hashimoto's disease. The CEA levels were inversely correlated with the serum T4 concentrations (P less than 0.001) and were positively correlated with the serum TSH concentrations (P less than 0.001), but not with the titers of serum antithyroid antibodies or the size of goiter in autoimmune thyroid disease. Moreover, the increase in CEA was significantly related to the duration of hypothyroidism (P less than 0.001). The high CEA levels in all hypothyroid patients decreased when the patients attained a euthyroid state after thyroid hormone therapy for 4-9 months. The gradual decrease in the serum CEA levels during treatment was roughly correlated with the decreases in serum cholesterol concentration and serum lactic dehydrogenase and glutamic oxalacetic transaminase activities. On Sephadex G-200 column chromatography of serum from hypothyroid patients, the CEA immunoreactivity, like purified standard CEA, was recovered in the large molecular weight fraction. These findings indicate that elevated CEA levels in hypothyroid patients do not necessarily indicate malignancy. CEA elevation in hypothyroidism may be caused by decreased degradation of CEA.

Adolescent↗
PubMed1981

Serum ratio of triiodothyronine to thyroxine, and thyroxine-binding globulin and calcitonin concentrations in Graves' disease and destruction-induced thyrotoxicosis.

The serum ratios of T3 to T4, and T4-binding globulin (TBG) and calcitonin concentrations were studied in cases of thyrotoxic Graves' disease and destruction-induced thyrotoxicosis. In 272 patients with Graves' disease, 209 of 240 (87%) untreated patients without complications had high T3 to T4 ratios (nanograms per micrograms) of more than 20. Six of 32 (19%) patients with Graves' disease who had complications (15 with pregnancy, 14 with increased TBG, and 3 with conditions associated with a low T3 syndrome) had high T3 to T4 ratios. Eleven of 74 (15%) patients with destruction-induced thyrotoxicosis (24 with subacute thyroiditis, 39 with postpartum transient thyrotoxicosis, and 11 with spontaneous transient thyrotoxicosis) had high T3 to T4 ratios. Patients who had serum T4 levels of more than 30 micrograms/dl and/or T3 levels of more than 800 ng/dl had Graves' disease. There was no significant correlation between the T3 to T4 ratio and activities of thyroid-stimulating immunoglobulins in thyrotoxic patients with Graves' disease who had no complications. The average serum levels of TBG in destruction-induced thyrotoxicosis and thyrotoxic Graves' disease were 20.7 +/- 4.3 micrograms/ml (mean +/- SD; n = 22), and 19.9 +/- 4.0 (n = 41), respectively, which were significantly lower than that in healthy subjects (22.7 +/- 4.4 micrograms/ml; n = 165), but there was no difference between the values in the two groups of thyrotoxicosis patients. The average serum level of calcitonin in destruction-induced thyrotoxicosis patients was 96.7 +/- 66.7 pg/ml (n = 21), which was significantly (P less than 0.05) higher than the values in patients with thyrotoxic Graves' disease (62.0 +/- 44.7 pg/ml; n = 26) and in healthy subjects (63.9 +/- 31.2 pg/ml; n = 29), but the difference in values in the two groups of thyrotoxicosis was not clinically useful because of considerable overlap of individual values. The T3 to T4 ratio is a simple and helpful index for the differentiation of the two types of thyrotoxicosis. A T3 to T4 ratio less than 20 in thyrotoxic patients before therapy is a laboratory signal of destruction-induced thyrotoxicosis or Graves' disease with complications, but final differentiation should be confirmed by measuring radioactive iodine uptake.

Adult↗
PubMed1981

Increase in plasma thyrotropin-releasing hormone in normal human pregnancy.

Maternal thyroid regulation in pregnancy was examined by measuring the concentrations of TRH, T4, T3, free T4 (by RIA), T4-binding globulin, TSH, PRL, and hCG in the sera of 30 normal pregnant women, 10 puerperally lactating women, and 10 normal pregnant women, 10 puerperally lactating women, and 10 normal nonpregnant female controls. Results showed that serum T4, T3, T4-binding globulin, PRL, and hCG, but not free T4 (by RIA), increased significantly during pregnancy. The plasma level of TRH was significantly higher (P less than 0.01) in the second trimester and significantly lower (P less than 0.05 1 month post partum than those values in nonpregnant controls. No significant correlations, however, were observed between the serum level of TRH and those of the thyroid hormones TSH, PRL, and hCG in pregnancy. The TRH-degrading activity of the plasma in the second trimester was normal. These results indicate that TRH secretion may be increased in the second trimester of pregnancy.

Adult↗
PubMed1981

Radioimmunoelectrophoretic analysis of proteins binding 3, 3', 5'-triiodothyronine in human serum.

The binding of purified 131I-3, 3', 5'-triiodothyronine (reverse T3) (rT3) to normal human serum components was investigated by a radioimmunoelectrophoretic technique. When anti-whole human serum was used, five distinct arcs of radioactivity were observed. Evidence was obtained that five of these radioactive arcs were not artifacts, but were due to components binding rT3. From the radioimmunoelectrophoretic patterns with specific antisera, five of these components were identified as thyroxine binding prealbumin, albumin, thyroxine binding globulin (TBG) and alpha 1-and beta-lipoproteins. No radioactive arc of TBG was detected in serum from a patient with TBG deficiency.

Alpha-Globulins↗
PubMed1981

Two-site immunoenzymometric assay for thyrotropin in dried blood samples on filter paper.

We describe a sensitive, simple, and rapid two-site immunoenzymometric assay for thyrotropin in dried blood samples on filter paper, for use in screening for neonatal primary hypothyroidism. In this method, two dried-blood spots of 3 mm diameter (equivalent to about 5.4 microliter of blood) are incubated overnight with anti-thyrotropin-beta-D-galactosidase complex in an anti-thyrotropin coated tube. Then the enzyme activity in the washed tube is determined fluorophotometrically. The range of thyrotropin measurable is 10 to 160 milli-int. units/L blood. Values for thyrotropin in dried blood samples determined by this method and those determined by radioimmunoassay correlated highly (r = 0.96).

Blood Specimen Collection↗