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Biomedical subjects

M Fukunaga

Publications and source records attributed to M Fukunaga.

At least 451 records · Page 25Linked to original sources

Antagonism by propidium of petite induction by ethidium and ethidium azide in Saccharomyces cerevisiae.

Propidium, a phenanthridinium dye similar to ethidium, did not induce petite mutations in non-growing yeast cells in contrast to ethidium. Combined exposure to ethidium and an excess of propidium for periods up to 2 h resulted in the expected petite induction expressed after subsequent plating on growth medium. As incubation was continued with propidium, the numbers of petites declined on subsequent plating whether the drug had been added before, during, or after the mutagenic treatment by ethidium. Propidium decreased petite induction by the monoazide analog of ethidium when applied before but not after photolytic attachment of the drug.

Azides↗

Accumulation of 201Tl-chloride in a parathyroid adenoma.

A 201Tl-chloride sacn was performed on a patient with primary hyperparathyroidism. 201Tl-chloride accumulated in the region of the right lower thyroidal pole and a diagnosis of parathyroid adenoma was confirmed intraoperatively. 201Tl-chloride imaging of a hyperfunctioning parathyroid gland seems to be useful for the detection and preoperative localization of a parathyroid adenoma.

Adenoma↗

Changes in sex hormones and calcium regulating hormones with reference to bone mass associated with aging.

Measurement of bone mineral content (BMC), intestinal 47Ca absorption, and calcium regulating hormones and sex steroids in serum were performed on 32 healthy aged subjects and 26 control young subjects. In BMC, there was a progressive fall after age 40, with the rate of decrease being greater in women than in men. A significant correlation was observed between BMC and testosterone in the men and between estrogens and BMC in the women, suggesting the possible importance of testosterone in men and estrogens in women in maintaining bone mass. Plasma PTH showed no change with age. However, the reserve capacity of the parathyroid was significantly reduced in the aged women. Serum levels of ionized calcium were low in aged subjects, indicating a possible alteration with age in the feedback control between ionized calcium levels and parathyroid hormone secretion. C-cell funtion was also decreased with age. Plasma 1,25-(OH)2D and 47Ca absorption tended to decrease with age. Age-related bone loss could be a reflection of the interaction of these hormonal imbalance occurring with age.

Adolescent↗

Deletion of mitochondrial genetic markers in yeast by ethidium and the photoaffinity probe, ethidium azide.

Induction of petite (cytoplasmic-respiration-deficient, rho-,rho-) mutations in yeast and deletion of mitochondrial drug-resistance genetic markers were compared after after treatment with ethidium and the corresponding photoaffinity probe, ethidium azide. Deletion of mitochondrial drug-resistance markers for chloramphenicol, erythromycin and oligomycin in these petite mutants was observed during prolonged treatment times with ethidium and with ethidium azide in the dark. A similar loss of drug-resistance markers was also observed in petites produced by photolytic treatment with the azide analogue, although the rate of loss appeared to be somewhat less. These results confirmed the usefulness of photoaffinity labeling with ethidium monoazide for studies of mitochondrial mutations.

Azides↗

[Clinical feature and calcitonin therapy on Paget's disease of bone (author's transl)].

Bone scintigraphy with 99mTc-MDP was performed on 8 patients with Paget's disease of bone. The radionuclide uptake by all the involved lesions was markedly increased, even in subclinical lesions without pain. Bone scintigraphy with 99mTc-phosphorous compounds were thought to be the most simple and sensitive technique to define the precise extent of the lesions, and to detect asymptomatic occult cases with Paget's disease. Possible A-V shunt was estimated in 3 cases by measuring the radioactivity over the lungs after the injection of 99mTc-MAA through a catheter into an artery which supplied the lesion. A-V shunt was calculated as 14.5%, 10.0% and 12.0%, respectively. An uptake study of 99mTc-MDP was attempted to quantify the effect of calcitonin treatment using a gamma camera combined with a computer. An "uptake ratio" was obtained for each lesion by dividing the count rate over the bone lesion by that over the control bone. Three cases of Paget's disease were treated with synthetic eel calcitonin analogue ([Asu1,7] E-CT) in a dose of 40 MRC unit per day. The effectiveness of CT therapy was evaluated by the X-ray film, the serum alkaline phosphatase activity (S-Al-P), the serum phosphate level, the serum calcium level and the "uptake ratio". No remarkable changes were obtained on bone X-ray films at one year after the initiation of the CT treatment in all cases. The S-Al-P levels did not show significant difference in the 2 cases, in which the S-Al-P levels were within the normal range before the treatment. In all cases, however, the "uptake ratio" of the diseased bone fell remarkably within the first three months and the rate of the fall was parallel to the decrease in the bone pain. It was considered that the "uptake ratio" on bone scintigraphy offered the most sensitive and reliable information in evaluating the CT treatment for Paget's disease.

Aged↗

Competitive protein binding assay for 1,25-dihydroxy-vitamin D in human plasma.

A sensitive and simplified radioreceptor assay for 1, 25-dihydroxyvitamin D (1, 25-(OH)2D) in human plasma was described and applied to preliminary clinical studies. Tritium-labeled 1, 25-(OH)2D3 was produced by incubating chick kidney homogenate with tritium labeled 25-hydroxyvitamin D3 (25-OHD3). A cytosol receptor was obtained from rachitic chick intestine (Kd=5.3 X 10(-11) M). Lipids in 5 ml of heparinized human plasma were extracted with dichloromethane, and 1, 25-(OH)2D was isolated by a Sephadex LH-20 column followed by high pressure liquid column chromatography. Recovery of 1, 25-(OH)2D3 after the plasma extraction and chromatography ranged from 58 to 100%. The assay was sensitive to 5 pg/tube. Diluted plasma from a patient on a high dose of 1 alpha-OHD3 showed a dilution curve parallel to the standard curve. The cytosol receptor showed a cross reactivity to various vitamin D3 metabolites physiologically present in the circulation and it was thought to be essential to eliminate other vitamin D3 metabolites 1,25-(OH)2D from plasma samples by high pressure liquid chromatography. Plasma concentrations of 1, 25-(OH)2D were, in the case of most normal subjects, distributed from 7 to 33 pg/ml and the range of distribution became greater in relation to age, indicating that plasma values should be matched to age. Whereas markedly high values of 1, 25-(OH)2D in plasma were found in some cases of primary hyperparathyroidism with prominent bone resorption, relatively low values were seen in some patients with chronic renal failure, senile osteoporosis, osteomalacia and hypercalcemia due to bone metastasis.

Adolescent↗

[Determination of thorotrast amount deposited in patients (author's transl)].

Thorotrast amount deposited in patients, chiefly in the liver and the spleen, was determined with a NaI detector and a Computerised Axial Tomography (CT). In the measurement of the gamma-rays with the NaI detector, the geometry-factors, that are the distance from the detector to the source, the attenuation of the gamma-rays in the tissue and the shapes of the liver and the spleen, were studied, and the mean amount deposited in the organs was determined. In the measurement with CT, the relationship of CT-Number and the amount of thorium was got, and the localized amount and the distribution in the organ were measured.

Gamma Rays↗