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Biomedical subjects

T Tsuchiya

Publications and source records attributed to T Tsuchiya.

At least 613 records · Page 34Linked 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

A comparative study of the effects of dentinal bonding agents and application techniques on marginal gaps in Class V cavities.

The effectiveness of eight dentinal bonding agents (DBA's) and four of their combinations in eliminating marginal gaps in class V cavities was evaluated by the bulk method of composite application and two different incrementation techniques. The cavities were prepared one-half in enamel and one-half in dentin. Basic fuchsin 0.5% in propylene glycol was used for detection of the presence of gaps. For each cavity, the presence of gaps was scored as 0 or 1, at five enamel and five dentin locations. Marginal gaps were present in 6% of all enamel locations and in 75% of all dentin locations investigated. The gap frequency was lowest at the enamel occlusal locations, it increased gradually toward the dentin, and attained the highest value at the gingival locations. In enamel, the occurrence of gaps was dependent on the DBA's but independent of the particular technique used. In dentin, there was significant difference in gap occurrence between DBA's with any of the incrementation techniques. The frequency of gap occurrence was not significantly changed by the incrementation techniques. The most effective single agent in producing gap-free restorations was the Gluma, and the most effective combination was the Gluma/Clearfil.

Adhesives↗
PubMed1987

Effectiveness of dextran sulfate on acute toxicity of paraquat in mice and rats.

The alleviation of acute toxicity of paraquat dichloride (PQ) by sodium dextran sulfate (DS), which is clinically used for antihyperlipemia was studied in mice and rats. When mice were orally given DS (2000 mg/kg) or sodium polystylene sulfonate (SPS), (2000 mg/kg) within 1 h (0, 10, 20, 30, 60 min) after PQ ingestion (200 mg/kg), the effectiveness of DS in alleviating PQ toxicity was greater than that of SPS. In rats treated with DS (2000 mg/kg) or SPS (2000 mg/kg), within 4 h (0, 2, 4 h) after PQ administration (200 mg/kg), the effectiveness of DS was less than that of SPS. However, the effectiveness of DS in the alleviation of toxicity was similar to that of SPS, when given to mice and rats (2000 mg/kg) within a short time after PQ ingestion (200 mg/kg). These results suggested that DS might serve as an antidote for acute toxicity of PQ.

Animals↗
PubMed1987

Syntheses of 23-C-alkylidene, and 23-N-containing derivatives of 5-O-mycaminosyltylonolide.

Several derivatives of 5-O-mycaminosyltylonolide substituted at C-23 have been prepared; these are 23-deoxy-23-C-methylene (3), 23-deoxy-23-C-(methoxycarbonylmethylene) (5), 23-deoxy-23-C-(ethoxycarbonylmethylene) (7), and 23-deoxy-23-C-(butoxycarbonylmethylene) (9), 23-deoxy-23-C-[(2E)-3-(ethoxycarbonyl)-2-propenylene] (11), and 23-deoxy-23-(dimethylaminoimino) (13), and 14-de(hydroxymethyl)-14-nitrile (16) derivatives. The key steps in these syntheses are the reactions of 2',4'-di-O-acetyl-3-O-tert-butyldimethylsilyl-23-deoxy-23-oxo-5-O- mycaminosyltylonolide diethyl acetal (1) with several Wittig reagents, 1,1-dimethylhydrazine and hydroxylamine. Antibacterial activities of these compounds are also described.

Anti-Bacterial Agents↗
PubMed1987

[Effect of modification of host immune activity on radiation therapy].

In this previous meeting, author reported that specific anti-tumor T cells, perhaps helper T cells, are induced in host mice after local irradiation to tumor. Immunostimulators were used following local irradiation to tumor. However, because suppressor T cells were also stimulated by these drugs, cyclophosphamide was used to suppress suppressor T cells. The results indicate that the combined use of immunostimulator and suppressor of suppressor T cells is very effective in radiation therapy. In the combined use of these drugs, the following three factors are very important: 1) whether the drug is administered before or after radiation, 2) the time interval between administrations of immunostimulator and suppressor T cells and local irradiation, and 3) dosage. Good effects were not obtained when dosage exceeded appropriate levels. The relationships among these factors are critical.

Animals↗
PubMed1987

[Effect of pancreatic juice diversion on gastric acid and gut hormone secretion].

In an effort to clarify the effect of pancreatic juice diversion (PJD) on the gastric acid and gut hormone secretion, models of PJD and non-PJD were prepared in dogs with Heidenhain pouch (HP). Two types of operative procedures, pancreatico-jejunostomy with Roux-Y reconstruction as a PJD model (RY group), and pancreatico-jejuno-duodenostomy using interposed jejunum as a non-PJD model (INT group) were carried out. The results were obtained as follows. 1. Both endocrine and exocrine function of the pancreas were preserved by either procedure. 2. Gastric acid secretion from HP after test meal ingestion was significantly increased postoperatively in RY group and was not affected in INT group. 3. Postprandial secretion of gastrin was not affected by these operative procedures in both RY and INT group. Secretion of GIP was significantly suppressed in RY group and was not changed in INT group. Secretion of enteroglucagon was significantly increased in both groups. These results indicate that significant increase of postprandial gastric secretion as shown in RY group is conceivably based on the significant suppression of GIP secretion produced by PJD.

Anastomosis, Roux-en-Y↗
PubMed1987

Acute blasticidin S poisoning.

Blasticidin S is an effective fungicidal aminocylonucleoside antibiotic against a rice blast disease. We presented the first 4 reported cases of acute poisoning from ingesting blasticidin S for suicidal attempts. Three of the patients were fatal. The symptoms observed in the patients included vomiting immediately after ingestion and severe, persistent, watery diarrhea. The toxic effects of blasticidin S were noted in ectodermal tissues including the skin, conjunctiva, cornea, and intestine. Massive loss of intestinal fluid resulted in progressively pronounced hypotension associated with tachycardia. The treatment of choice for the poisoning consists of intravenous fluid administration and the management of body water and electrolyte balance.

Adult↗
PubMed1986

[Health check on radiation workers in the nuclear energy industry using Todai Health Index].

In the nuclear energy industry, the plants are located far from urban areas and the working environments are generally separate from each other for radiation protection purposes. The health investigation on radiation workers in the nuclear energy industry was carried out using the Todai Health Index questionnaire in 1982, 1983 and 1984. As a control study non-radiation workers on the other several working fields were investigated in the same manner. The results showed that the status of radiation workers in the nuclear energy industry is similar to that of the workers in the other working fields and the THI questionnaire is useful to know health and working status of a group of workers.

Adult↗