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Biomedical subjects

T Sakurada

Publications and source records attributed to T Sakurada.

At least 307 records · Page 17Linked to original sources
PubMed1980

Rapid effect of triiodothyronine on the mitochondrial pathway in rat liver in vivo.

Intravenous infections of minute doses of triiodothyronine were administered to thyroidectomized rats 30 minutes before they were killed. Hepatic mitochondria were isolated rapidly and formation of adenosine triphosphate and consumption of oxygen were assessed by a 2-minute incubation. Hormone injection enhanced formation of adenosine triphosphate 114 to 217 percent over control values, with a proportionate increase in consumption of oxygen. The ratio of phosphate to oxygen was about 2.0, signifying tightly coupled oxidative phosphorylation. Stimulation was not abolished by injection of cycloheximide, puromycin, actinomycin D, or chloramphenicol 1 hour before the rats were killed. This signifies direct mitochondrial stimulation by triiodothyronine in the absence of protein synthesis.

Adenosine Triphosphate↗
PubMed1980

Long-term results of radioiodine (131I) therapy in 331 patients with Graves' disease.

To evaluate the long-term results of 131I treatment for Graves' disease, the thyroid function was studied in 331 patients 5-17 years after this therapy. Twenty-five patients were hypothyroid and had already been on thyroid medication. Among the remaining 306 patients without any treatment for thyroid disorder, 188 patients (61.4%) had a normal thyroid-stimulating hormone (TSH) level (less than 10 microU/ml) of whom 151 were euthyroid with normal thyroxine (T4) and triiodothyronine (T3) level. 118 patients (38.6%) had a high TSH level, of whom 22 were hypothyroid with low T4 and T3 levels and 38 with normal T3 and low T4 levels, and 14 patients out of this 38 were clinically hypothyroid. Although all of the patients with high TSH levels do not per se require the replacement therapy for hypothyroidism, the overt hypothyroidism seems to occur sooner or later in patients with a lower T4 level. Among 331 patients studied, 61 (18.4%) were clinically hypothyroid. The incidence of hypothyroidism was 20.7% after 10 years of 131I treatment and 33% after 15-17 years. The incidence of patients with high TSH levels was 50% after 10 years of 131I treatment and 60% after 15-17 years. Both of cumulative incidence of hypothyroidism and patients with high TSH levels increased linearly with years after the treatment, which coincided with the linear decrease of mean T4 and T3 levels and linear increase of mean TSH level with years after the treatment. The difference of positive incidence of antithyroid antibodies between cases of normal TSH level and high TSH level was not significant.

Autoantibodies↗
PubMed1980

A solid-phase radioimmunoassay for free thyroxine in serum compared with equilibrium dialysis method.

Serum free thyroxine (T4) was measured by a solid-phase radioimmunoassay in various thyroid states and in those associated with changes in serum T4-binding proteins. And it was compared with the value obtained by product of total serum T4 and of per cent free T4 by equilibrium dialysis. Serum free T4 concentrations were found to be 1.34 +/- 0.33 ng/100 ml (mean +/- S.D.) in 51 normal subjects, 5.02 +/- 1.41 ng/100 ml in 29 hyperthyroid patients, 0.16 +/- 0.15 ng/100 ml in 12 hypothyroid patients, and the value in each individual of the latter two groups was significantly different from normal. Serum free T4 was normal of 1.23 +/- 0.22 ng/100 ml in 7 pregnant women and all had free T4 levels within the normal range. Moreover, five out of six patients with decreased thyroxine-binding globulin had normal free T4 levels, though their mean value (0.85 +/- 0.20 ng/100 ml) was significantly lower than the normal value. An excellent correlation (r = 0.93) was observed between values for serum free T4 obtained by the present method and those by the equilibrium dialysis method. The simplicity, accuracy, sensitivity, and specificity of this assay render it highly attractive for routine clinical determination.

Dialysis↗
PubMed1980

Measurement of triiodothyronine in urine.

A radioimmunoassay procedure to measure triiodothyronine (T3) in unextracted urine is described. One hundred microliter of T3 standards or samples were incubated with 100 microliter of T3 antiserum (1:40,000), 100 microliter of tracer 125I-T3 and 700 microliter of 0.05 M borate buffer, pH 8.6. Separation of free from bound antigen was achieved by dextran coated charcoal. The cross-reaction of L-T3 with L-T4 in this assay system was less than 0.2%. Dilution of high T3 urine was parallel to the standard curve. Recovery was 101 +/- 8%. Coefficients of variation were 3-8% within each assay and 13% between assays. Euthyroid subjects excreted 0.81 +/- 0.39 microgram (mean +/- S.D.) in 24 hr. Similar values were obtained in pregnant women, euthyroid patients with chronic thyroiditis, and a patient with thyroxine-binding globulin deficiency. Excretion of urinary T3 was high (7.48 +/- 3.32 microgram/24 h) in patients with hyperthyroidism, and low (0.14 +/- 0.15 microgram/24 hr) in patients with hypothyroidism. Urinary T3 excretion was almost undetectable in terminal renal failure. Positive correlations were found between urinary T3 and serum total T3 (r = 0.89) and especially serum free T3 (r - 0.97). A positive correlation was also found between urinary T3 and creatinine clearance (r = 0.63). Mean urinary clearance of T3(CT3=Urinary T3 excretion/serum free T3 was 166 ml/min and was significantly higher than their mean creatinine clearance (110 ml/min). The measurement of T3 in urine is reliable and easy to perform, and may allow a new approach to the understanding of thyroid hormone metabolism.

Female↗
PubMed1979

[Effects of diazepam on rage reaction elicited by the lateral hypothalamus (LH) and on single unit activities in the LH and the basal medial amygdaloid nucleus (Abm) in cats (author's transl)].

Effects of diazepam were examined on the whine reaction elicited by LH stimulation and on unit activities in the LH and Abm in cats. The spontaneous firing frequency of Abm neurons was 5 to 30 spikes/sec and in all 6 neurons isolated the firing frequency increased by non-nociceptive and/or clap-stimulation. Diazepam decreased the spontaneous firing frequency of all Abm neurons isolated and the increased firing frequency elicited by non-nociceptive and/or clap-stimulation was also depressed by diazepam. The spontaneous firing frequency of neurons in the LH was 4 to 5 spikes/sec and all 6 neurons isolated firing frequency increased by non-nociceptive stimulation. Only one of 6 neurons, however, was activated by clap-stimulation. Diazepam decreased the spontaneous firing frequency of all LH neurons. Out of 6 neurons responsive to non-nociceptive stimulation, 3 were also depressed by diazepam. The other neurons were not affected by diazepam. These results suggest that depressed action of diazepam on the whine reaction elicited by the LH stimulation may be related to the decrease of firing in the Abm and/or the LH by diazepam.

Amygdala↗
PubMed1979

Carbohydrate metabolism in Down's syndrome.

Carbohydrate metabolism was studied in eight patients with Down's syndrome, aged 8 to 18 years. Diabetic glucose tolerance was observed in only one patient with obesity. This impaired glucose tolerance was improved with the weight reduction due to diet restriction. The flat glucose tolerance curves with low peak values were also observed in the other two patients. In the remaining five patients, normal glucose tolerance was obtained. Insulin response and free fatty acid levels during oral glucose load were not characteristic except for the diabetic patient with obesity. The sera of Down's syndrome showed normal binding capacity for insulin. These results suggest that obesity might partly participate in the impaired glucose tolerance in Down's syndrome.

Adolescent↗