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Biomedical subjects

K Takai

Publications and source records attributed to K Takai.

At least 217 records · Page 12Linked to original sources
PubMed1988

Sequential changes in the prostate of rats treated with chlormadinone acetate, testosterone and N-nitroso-N-methylurea.

An attempt was made to induce prostatic adenocarcinoma in rats. Temporary chemical castration of F344 rats was achieved by administration of diet containing 0.05% chlormadinone acetate (CMA) for three weeks. The prostate was then stimulated by three consecutive daily intramuscular injections of testosterone propionate (100 mg./kg.). On the day after the last testosterone injection, N-nitroso-N-methylurea (NMU) (50 mg./kg.) was injected intravenously. Animals were sacrificed 10 days and 4, 20, 40 and 60 weeks after NMU treatment. Well-differentiated adenocarcinomas were obtained in three of fifty-four animals (5.6%) by this treatment and a high incidence of simple hyperplasia (88%) and atypical hyperplasia (19%) was also observed at 60 weeks. More studies are necessary to develop a protocol resulting in more rapid induction of prostatic adenocarcinomas at higher incidence.

Adenocarcinoma↗
PubMed1988

Validity of short-term examination for antipromoters of bladder carcinogenesis.

Various compounds were screened for antipromoter activity in bladder carcinogenesis in rats with a view to using them clinically to inhibit postoperative intravesical ectopic tumor growth of superficial papillary bladder cancer. Their inhibitions of the effect of sodium saccharin in maintaining increased agglutinability of bladder cells by concanavalin A were examined in 4-week tests. The compounds found to inhibit the effect of saccharin were alpha-tocopherol, ascorbic acid, aspirin, all-trans aromatic retinoid, alpha-difluoromethylornithine, sodium cyanate and p,p'-diamino-diphenylmethane. Considering the toxicities of some of these chemicals, ascorbic acid and alpha-difluoromethylornithine were concluded to be the most promising for future clinical trials.

Agglutination↗
PubMed1988

Effects of Ca++-antagonists on systemic capacitance vessels and venous return curves of dogs--a study with mean circulatory pressure.

We measured mean circulatory pressure (MCP) in anesthetized, open-chest dogs before and after intravenous administration of Ca++-antagonists to estimate the effects on systemic capacitance vessels and on venous return (VR) curves both with and without continuous intravenous infusion of norepinephrine (NE). Diltiazem (300 micrograms/kg) decreased total peripheral resistance (TPR) and MCP significantly. Nifedipine (5 micrograms/kg), nicardipine (30 micrograms/kg) and verapamil (200 micrograms/kg) decreased TPR significantly without any change in MCP in the absence of NE, but with the exception of verapamil, they decreased MCP in the presence of NE. This indicates that diltiazem relaxed the systemic capacitance vessels, and nifedipine and nicardipine significantly decreased the tone of the systemic capacitance vessels that had been previously elevated by NE, but this action was very slight with verapamil. These Ca++-antagonists rotated VR curves clockwise, decreased resistance to VR (RVR) and increased VR both in the presence and absence of NE. It was suggested that the decrease in the RVR would be at least partially responsible for the increase in the VR.

Animals↗
PubMed1988

Effect of tetrahydrobiopterin and 5-hydroxytryptophan on hereditary progressive dystonia with marked diurnal fluctuation: a suggestion of the serotonergic system involvement.

A daughter and her mother developed hereditary progressive dystonia with marked diurnal fluctuation (HPD) at the age of 4 and 34, respectively. L-Dopa, tetrahydrobiopterin (BH4) or 5-hydroxytryptophan (5-HTP) was orally administered to them. L-Dopa cured completely their symptoms. 5-HTP as well as BH4 improved their symptoms, especially dystonic movements. Biopterin and 5-hydroxyindoleacetic acid concentrations in CSF increased during BH4 medication. These findings suggest that the serotonergic system of the central nervous system might play some role in the pathogenesis of dystonia in HPD.

5-Hydroxytryptophan↗
PubMed1988

Changes in glucose uptake by and phlorizin binding to brush-border membrane vesicles of small intestine from streptozotocin-induced diabetic rats.

The changes in the intestinal glucose transport in streptozotocin-induced diabetic rats have been demonstrated with brush-border membrane vesicles. When Na+-dependent D-glucose uptake and phlorizin binding activities were compared, both significantly increased either in the jejunum or ileum of diabetic rats compared with those of control. Kinetic studies showed the increases in the Vmax of glucose transport and the maximum binding of phlorizin (Bmax), whereas the Kt and Kd remained unchanged, respectively. These results suggested that the increase in glucose transport in diabetic rat intestine was due to the increase in the number of the intact glucose transporters.

Animals↗
PubMed1988

Treatment of a case of asynchronous bilateral renal cell carcinomas with inferior vena caval thrombus and hepatic metastases.

A 56-year-old man underwent a right radical nephrectomy with removal of a vena caval thrombus and resection of hepatic metastases for right renal cell carcinoma. Twenty-one months after the first operation, a left renal cell carcinoma was detected which was treated with left radical nephrectomy and followed by hemodialysis. The patient then enjoyed an active life for 14 months but died 18 months after his second operation due to lung metastasis. Bilateral radical nephrectomy and hepatic resection may be justified since there is no strongly effective adjuvant therapy for such advanced cases.

Carcinoma, Renal Cell↗
PubMed1987

Analyses of avidin-biotin complexes with lectins of membrane glycoproteins in the urinary bladder of rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

The bladder epithelium was examined by staining with avidin-biotin complexes with lectins to determine the early membrane changes during bladder carcinogenesis in rats treated with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BHBN). Concanavalia ensiformis (Con A), Triticum vulgaris (WGA), Ricinus communis (RCA) and Arachis hypogaea (PNA) were used as probes. The cellular distributions of lectin particles were distinguished into membranous and cytoplasmic patterns. Normal bladder cells stained very slightly and showed a spotty membranous pattern. After treatment of rats with BHBN for two or three weeks, staining became stronger and its pattern changed from a membranous to a cytoplasmic type. The staining of bladder cancer cells induced by BHBN varied from area to area and with different lectins. These data indicated that changes in carbohydrates occur in the bladder cell membrane during the early phase of carcinogenesis.

Animals↗
PubMed1987

Thymic enlargement following treatment for a metastatic germ cell tumor: a case report.

We describe a patient with metastatic testicular carcinoma in whom an anterior mediastinal mass developed 8 months after complete remission following chemotherapy and surgery. The mass was excised and pathological examination showed benign thymic hyperplasia. An anterior mediastinal mass encountered after successful chemotherapy does not always imply recurrence or relapse of malignant disease. The possibility of a benign etiology must be considered to prevent inappropriate treatment.

Adult↗