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Biomedical subjects

M Tsuda

Publications and source records attributed to M Tsuda.

At least 487 records · Page 27Linked to original sources
PubMed1987

Properties of the membrane-bound 5'-nucleotidase and utilization of extracellular ATP in Vibrio parahaemolyticus.

Vibrio parahaemolyticus utilized ATP, ADP or AMP as the sole source of carbon. About three times higher activity of membrane-bound 5'-nucleotidase was observed in cells grown in the presence of these nucleotides than in their absence: and therefore the enzyme seems to be inducible. Since the 5'-nucleotidase activity could be measured with whole cells, the active site of this enzyme appears to be outwardly oriented. Both Mg2+ and Cl- were required for activity. Among the divalent cations tested, Mn2+ and Co2+ could replace Mg2+ to some extent, whereas Zn2+ strongly inhibited activity. Among the anions tested, Br-, I- and NO3- could replace Cl-, but SO4(2-) and CH3COO- could not. When cells were grown with ATP, Cl- was indispensable and Zn2+ strongly inhibited growth. Therefore, it is concluded that extracellular ATP and other 5'-nucleotides are cleaved by the membrane-bound 5'-nucleotidase outside the cells and that the adenosine produced is then utilized.

5'-Nucleotidase↗
PubMed1987

[The efficacy of temporary retention chemotherapy of the treatment of polyps in the remnant rectum of familial polyposis after total colectomy and ileorectostomy--a case report].

A case of familial polyposis is reported. The patient was a 24-year-old woman on whom total colectomy followed by ileorectostomy had been performed. However, there were multiple polyps remaining in the remnant rectum. For the treatment of these residual polyps, a new chemotherapeutic method known as Temporary Retention Chemotherapy (TRC), originally devised by us for the treatment of advanced gastric cancer, was applied. A balloon catheter was inserted and fixed into the rectum via the anus for the treatment of the rectal tumors. Through the catheter, high-dose 5-fluorouracil (5-FU) solution was injected into the rectum and retained there for one hour before being discarded. During the therapy, the patient was asked to change her position of recumbency at certain intervals, so that the 5-FU solution could act evenly on the lesions in question. This therapy was repeated twice a week, and followed by routine endoscopic studies. A total dose of 5,700 mg of 5-FU was necessary for obtaining a complete response of the remnant lesions. 6 months later, 4 polyps were found, and TRC was again applied, resulting in disappearance of the polyps again after the therapy. So far, no side-effect have been noted as a result of this therapy. She is currently still alive without any residual polyps, carcinoma or metastasis 6 years after the operation.

Adenomatous Polyposis Coli↗
PubMed1987

[Clinical study on papillary adenocarcinoma of the thyroid].

Disagreement still exists in relation to the extent of thyroid resection and lymph node dissection for papillary adenocarcinoma. Twenty eight cases comprise the present study. Seventy four percent of all cases studied revealed metastatic regional nodes, even in t1-cases, 73% of the treated cases showed metastatic nodes. The present results suggest that a modified neck dissection of the ipsilateral nodes would seem necessary in treating this carcinoma. Lobectomy with modified neck dissection is feasible, if the tumor is localized, but if it is not, then a total or subtotal thyroidectomy, combined with modified neck dissection, is necessary.

Adenocarcinoma, Papillary↗
PubMed1987

Effect of cigarette smoking and dietary factors on the amount of N-nitrosothiazolidine 4-carboxylic acid and N-nitroso-2-methyl-thiazolidine 4-carboxylic acid in human urine.

The effects of cigarette smoking and dietary factors on urinary excretion of N-nitrosothiazolidine 4-carboxylic acid (NTCA; N-nitrosothioproline) and N-nitroso-2-methylthiazolidine 4-carboxylic acid (NMTCA; N-nitroso-2-methylthioproline) were studied in a male volunteer and in healthy Japanese subjects from the general population and Seventh-Day Adventists (SDA). Twenty-four-hour urine samples from the male volunteer were collected on 20 smoking days and 20 nonsmoking days during ingestion of a fixed diet, and the amounts of urinary N-nitrosamino acids were analysed by gas chromatography-thermal energy analysis. Cigarette smoking caused about two-fold (significant) increases in the amounts of NTCA and NMTCA in the volunteer. In the male subjects from the general population, not controlled for diet, the amounts of NTCA and NMTCA in 24-h urines of smokers were also significantly higher than those of the nonsmokers. The urinary excretions of NTCA and NMTCA in SDA were lower than those of nonsmokers in the general population. It was concluded that cigarette smoking is one of the important factors in determining the amounts of NTCA and NMTCA in human urine. Dietary factors also apparently influence the urinary levels of these N-nitrosamino acids. In addition, an apparent sex difference in the urinary excretion of NTCA and NMTCA (about two-fold higher in females) was observed in the general population but not in SDA. The N-nitrosoproline (NPRO) level was significantly higher in SDA than in nonsmokers in the general population.

Adult↗