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Biomedical subjects

T Kakegawa

Publications and source records attributed to T Kakegawa.

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

Effects of macrocyclic polyamines and polymethylenediamines on reactions influenced by polyamines.

The effects of macrocyclic polyamines and polymethylenediamines on various reactions influenced by polyamines have been studied. Among the amines tested, 2,3,4,3- and 3,3,3,4-cyclic polyamines, NH2(CH2)6NH2 and NH2(CH2)8NH2 had some ability to stimulate polyphenylalanine synthesis, globin synthesis and rat liver isoleucyl-tRNA formation. The degree of stimulation was at most 40% of that obtained by polyamines. In the degradation of poly(C) by bovine pancreatic RNAase A, all tested amines stimulated the degradation. In the NADPH-dependent lipid peroxidation of rat liver microsomes, the degree of inhibition by 2,3,2,3- or 2,3,3,3-cyclic polyamine was greater than that by spermine. The hydrolysis of ATP by an oligomycin-sensitive ATPase was inhibited by 2,3,4,3- and 3,3,3,4-cyclic polyamines, NH2(CH2)10HN2 and spermine at somewhat comparable levels. None of the macrocyclic polyamines or polymethylenediamines stimulated the growth of a polyamine-requiring mutant of Escherichia coli. Possible explanations for the differences in the effects of amines on the various reactions are discussed.

Adenosine Triphosphatases↗
PubMed1980

Carcinoma within a middle esophageal (parabronchial) diverticulum: a case report and the review of the literature.

A case of carcinoma developed in the middle esophageal (parabronchial) diverticulum is reported. In recent literature, 44 cases of carcinoma in esophageal diverticulum were reported. Most of the patients who had carcinoma in a diverticulum have a long-term history of symptom related to diverticula. Prognosis of these patients was poor because the carcinomas were far advanced when they were found. Therefore, the patient with esophageal diverticulum should be checked with esophagogram, esophagoscopy and biopsy, considering the possibility of development of carcinoma. Most of the cases of carcinoma in a diverticulum were treated with diverticulectomy. However, we consider that radical esophagectomy is a better method of treatment.

Aged↗
PubMed1980

Cell kinetic study of human cancers transplanted to nude mice.

Using 3H-TdR pulse labelling, the cell kinetics of four, serially transplantable, human tumors were studied in athymic nude mice. Squamous cell carcinoma of the lung, tongue and esophagus showed relatively similar cell kinetic parameters. The growth of an oat-cell carcinoma was initially very slow in mice and its growth fraction was unexpectedly small with a relatively low labelling index. Its postmitotic phase was very short. It was concluded that the nude mice/human tumor system may be useful for cell kinetic studies of human tumors from the standpoint of tumor biology and therapy.

Animals↗
PubMed1979

67Ga scanning in the evaluation of esophageal carcinoma.

Eighty-nine patients with histologically proved esophageal carcinoma were scanned with 67Ga to screen for extramural tumor extension and lymph-node involvement. Radiation dose and reduction of uptake were correlated. 67Ga accumulation indicated extramural extension with a sensitivity of 67% and a specificity of 93%. Marked uptake in an extraprimary site in the mediastinum or upper abdomen indicated lymph-node involvement with a sensitivity of 27% and a specificity of 100%. Irradiation with more than 20 Gy (2,000 rad) reduced uptake (P less than 0.05). 67Ga scanning appears to be useful in the evaluation of esophageal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1978

Thyroid function and polyamines. III. Changes in ornithine decarboxylase activity and polyamine contents in the rat thyroid during hyperplasia and involution.

Changes in ornithine decarboxylase (ODC) activity and in polyamine contents of the rat thyroid were studied under various experimental conditions. Methylthiouracil (MTU) treatment produced several-fold increases in the thyroid ODC activity and in the content of putrescine, spermidine and spermine within a week. While serum thyrotropin (TSH) levels increased gradually up to 3 weeks, the content of both putrescine and spermidine tended to reach a plateau after 2 weeks of the goitrogen treatment; spermine content continued to increase progressively for 3 weeks. Discontinuance of MTU at 7 days resulted in a rapid decline in the elevated thyroid ODC activity, followed by a diminution of putrescine, spermidine and RNA contents. Thyroidal putrescine, spermidine and RNA responded more sensitively to both introduction and withdrawal of TSH stimulation than thyroidal spermine and DNA. Excess iodide, having no effect on the basal level of thyroid ODC, suppressed the MTU-induced increase in this enzyme activity without affecting circulating TSH, thyroxine (T4) and triiodothyronine (T3) levels. There was a significant negative correlation between the ODC activity and intrathyroidal concentration of iodine in MTU-pretreated rats. Theophylline increased the thyroid weight and ODC activity when given to rats fed with a subeffective dose of MTU. Analyses of serum TSH, T4, T3 and of thyroidal iodine revealed that TSH-induced thyroid ODC activity was suppressed by increased circulating thyroid hormones and/or intrathyroidal iodine. Furthermore, it was suggested that thyroid hormones and excess iodide acted directly on the thyroid to alter polyamine biosynthesis, possibly by changing the responsiveness of the gland to TSH.

Animals↗
PubMed1978

Changes of LH, TSH, GH, FSH and PRL in pituitaries and sera of rats after thyroidectomy and thyroxine treatment as studied by radioimmunoassay and disc electrophoresis.

Rat pituitary hormones (LH, TSH, GH, FSH and PRL) were located in polyacrylamide gels after the separation of rat pituitary homogenate with the aid of electrophoresis. Furthermore, the incorporation of 3H-glucosamine and 14C-leucine into various protein fractions of incubation media and pituitaries incubated for 6 h in vitro, homogenized and then subjected to disc electrophoresis was measured in six groups of rats: 1. control; 2. two weeks after thyroidectomy (Tx); 3.--6. two weeks after thyroidectomy and injected 20 micrograms L-thyroxine (T4) i.p. per animal at 6, 12, 24 and 48 h before sacrifice, respectively. A decrease of 14C-leucine incorporation into GH and PRL after thyroidectomy was found which was improved by T4 treatment. Moreover, an increase of 3H-glucosamine and 14C-leucine incorporation into TSH zone and origin zone was observed, the former presumably representing the extracted TSH and the latter consisting of unextracted portion of TSH, other hormones and unidentified proteins. Such increase was significantly less after T4 treatment. Finally, changes of radioimmunoassayable LH, TSH, GH, FSH and PRL in pituitaries and sera of analogous groups of rats, but consisting of another animals were measured. The content of TSH in the pituitary slightly increased after Tx, but increased further after T4 treatment. In contrast, the content of all other hormones in the pituitary decreased after Tx, while T4 treatment resulted in a stepwise increase. In plasma, a significant decrease of GH and PRL after Tx was found with no remarkable changes after T4 treatment. The level of LH and FSH was unchanged, while that of TSH increased significantly after Tx and sharply decreased to the original level as early as at 6 h after the injection of T4.

Animals↗
PubMed1976

Changes in cyclic AMP level of rat thyroid by acute and chronic stimulation of thyrotropin in vivo.

To assess a possible postmortem change in the level of cyclic AMP, the thyroids were snap-frozen at various time intervals after removal. Rats were fed a low-iodine diet (LID) with PTU for 2 weeks and a week after PTU discontinuation (PTU withdrawal). In all cases, the cyclic AMP level tended to increase as time elapsed from removing till fixing the thyroids, but in the PTU withdrawal group, the level was rapidly increased 2-fold after 5 min. In an acute experiment, the thyroids were removed under anesthesia and frozen rapidly. Intravenous administration of ovine thyrotropin (250 mU) and TRH (500 ng) brought about a rapid increase in the thyroidal level of cyclic AMP to 40% to 20% over the control level. Two weeks after PTU treatment, circulating thyrotropin was increased to a maximum of 19-fold and a further enhancement ("rebound") was observed after PTU withdrawal. PTU treatment led to an increase in the thyroidal level of cyclis AMP pre mug DNA to 60% over the control value. Following PTU withdrawal, the rise in the level of cyclic AMP returned to the normal level. However, there was no change in the concentration when it was expressed as per mg wet tissue weight. Therefore, the increase in the thyroidal concentration of cyclic AMP per mug of DNA may be due to an increase in volume of the follicular cells.

Animals↗