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Biomedical subjects

T Shiratori

Publications and source records attributed to T Shiratori.

At least 19 recordsLinked to original sources
PubMed1992

Molecular cloning of the gene encoding Thiobacillus ferrooxidans Fe(II) oxidase. High homology of the gene product with HiPIP.

The amino-terminal sequence of Thiobacillus ferrooxidans Fe(II) oxidase (linked to cytochrome c552) was determined, and the iro gene that encodes this enzyme was cloned using degenerate oligonucleotides as a probe. The DNA sequence of a region (856 base pairs) which encompasses the iro gene revealed that the enzyme was encoded by a 273-base pair open reading frame and consists of 90 amino acids, including a possible 37-residue signal sequence. The iro gene seems to be transcribed independently of any other gene because the transcriptional products are 0.45 and 0.6 kilobases in size. Current protein databases revealed that the iro gene product is a new member of the high redox potential iron sulfur proteins, which generally function in electron transport but do not show enzymatic activity.

Amino Acid Sequence↗
PubMed1992

Electrotransformation of Thiobacillus ferrooxidans with plasmids containing a mer determinant.

The mer operon from a strain of Thiobacillus ferrooxidans (C. Inoue, K. Sugawara, and T. Kusano, Mol. Microbiol. 5:2707-2718, 1991) consists of the regulatory gene merR and an operator-promoter region followed by merC and merA structural genes and differs from other known gram-negative mer operons. We have constructed four potential shuttle plasmids composed of a T. ferrooxidans-borne cryptic plasmid, a pUC18 plasmid, and the above-mentioned mer determinant as a selectable marker. Mercury ion-sensitive T. ferrooxidans strains were electroporated with constructed plasmids, and one strain, Y4-3 (of 30 independent strains tested), was found to have a transformation efficiency of 120 to 200 mercury-resistant colonies per microgram of plasmid DNA. This recipient strain was confirmed to be T. ferrooxidans by physiological, morphological, and chemotaxonomical data. The transformants carried a plasmid with no physical rearrangements through 25 passages under no selective pressure. Cell extracts showed mercury ion-dependent NADPH oxidation activity.

Blotting, Southern↗
PubMed1992

Long-term results of pylorus-preserving gastrectomy for gastric ulcer.

The postoperative results of pylorus-preserving gastrectomy (PPG) for gastric ulcer performed in 134 patients during the past 25 years (mean postoperative period, 16.6 years) were studied. The incidence of postoperative complications was low. Dumping syndrome occurred in only 4.4% and 0% of cases as assessed by questionnaire and interview, respectively. Four (5.4%) of 74 patients available for this study had ulcer recurrence. In one of these four patients concurrent gastroduodenal ulcer was suspected from preoperative gastric analysis. The site of recurrence was found in all cases to be the remnant antral gland area along the greater curvature between the proper gastric gland area and the duodenum. Basal and maximal acid outputs at the time of relapse were significantly higher in patients with recurrence than in patients without recurrence. The fasting and postprandial serum gastrin levels were high in one patient with recurrence, whose antrum was preserved as long as 3 cm proximal to the pyloric ring; this was longer than that described in our original method of PPG. In two other recurrent cases the serum gastrin levels were not different from those in nonrecurrent cases. Immunohistochemical examination of the residual antrum showed no increase in the G-cell density in patients either with or without recurrence. These results suggest that the long-term quality of life of patients treated with PPG remains favorable. Recurrence rate can be further reduced if PPG is strictly indicated for gastric ulcer only and carried out by meticulous surgical techniques. In the pathogenesis of the ulcer recurrence the role of gastrin release from the residual antral mucosa seems to be limited.

Adult↗
PubMed1979

Heterotransplantation of human gastric carcinomas into nude mice.

A total of 33 specimens of human gastric carcinoma were used for transplantation into nude mice. Initital tumor "take" was accomplished in 15 of the 33 tumors, and the transplantability rate was 45.5%. Transplantability correlated with histologic type, but not with clinical stage or Borrmann's classification. The transplantability rate of differentiated carcinomas, such as well-differentiated tubular adenocarcinoma, moderately differentiated tubular adenocarcinoma, and papillary adenocarcinoma was greater than that of poorly differentiated tumors, such as poorly differentiated adenocarcinoma and mucinous adenocarcinoma. The growth patterns of transplanted tumors were divided into 3 types: rapid, slow, and persistent. There were no specific relationships between growth pattern and histologic type. All histologic types, except signet ring cell carcinoma, could be transplanted serially. Tumor growth became rapid after serial transfer. However, the original histology of these tumors was unchanged. No invasion or metastases were encountered. Intraperitoneal injection of a tumor cell suspension, prepared from subcutaneous transplants of a poorly differentiated adenocarcinoma of Borrmann type III, grew in an ascites form, with invasion and metastasis. Ascitic fluid accumulated within 3--6 weeks after injection. Subsequently, intravenous injection of ascites fluid produced metastases in nude mice. The histology of the subcutaneous tumor was similar to that of the original tumor from the patient.

Adenocarcinoma↗
PubMed1978

Conversion of a poorly differentiated human adenocarcinoma to ascites form with invasion and metastasis in nude mice.

Cells (1 X 10(7)/0.5 ml) from a Borrmann type III poorly differentiated adenocarcinoma of the human stomach were injected ip into nude mice. The injection resulted in ascites carcinoma with invasion (carcinomatous peritonitis) and liver metastasis. The inoculum was obtained from subcutaneous tumors at passage 9 in nude mice that had received serial transplants from the patient with Borrmann type III poorly differentiated adenocarcinoma of the stomach. Serial transfers of 1.5 X 10(6) dispersed cancer cells/0.5 ml into the peritoneal cavity of nude mice converted this adenocarcinoma to an ascites form. Hemorrhagic ascites accumulated within 3 weeks at the first passage and 4-6 weeks in serial passages. Carcinomas peritonitis occurred consistently and was observed in the diaphragm, mesenteries, omentum, and pancreas; metastases were seen in the liver and spleen. Subsequently, iv injection of ascites at passage 3 (6 X 10(5) cells/0.2 ml) into nude mice produced metastatic lesions in the lung and the heart. The histology of the invasive and metastatic lesions in the nude mice was similar to that of the original tumor in the patient with stomach carcinoma.

Adenocarcinoma↗
PubMed1977

Pylorus-preserving procedure in partial and total gastrectomy.

1. The operative technique and the postoperative results of the original pylorus-preserving gastrectomy (PPG) and those of the Maki procedure as applied to cases of total gastrectomy are reported briefly. 2. The essence of these operations is to retain the pyloric cuff of 1.0-1.5 cm in length in order to preserve sphincteric function without the use of the drainage procedure. Ingested food was seen to empty gradually and rhythmically through the pyloric ring into the duodenum thereby avoiding dumping syndrome and reflux esophagitis. 3. As gastric acidity is reduced sufficiently by PPG, this method is to be recommended for treatment of intractable gastric ulcer cases and other benign lesions in which the foci are located in the distal half of the stomach. Though the method seems to be also useful in selected cases of duodenal ulcer, stenosis at the level of the pylorus and duodenum may preclude the application of the method. 4. The Maki procedure with jejunal interposition following nearly-total proximal gastrectomy is recommended in patients whose pylorus and its surroundings have remained free of tumor.

Dumping Syndrome↗
PubMed1977

Effects of various types of vagotomy on gastrin release and gastric secretion in dogs.

Changes of serum gastrin and acid secretory responses to histamine, feeding and insulin stimulation before and after various types of vagotomy (TV, SV, SPV and SAV) were investigated in Heidenhain pouch dogs. The following results were obtained: (1) The acid secretory response to histamine slightly decreased after various types of vagotomy. (2) The responses of serum gastrin and acid secretion to feeding were elevated after various types of vagotomy. (3) The serum gastrin response to insulin was highly increased after SPV and TV, whereas the response was slightly increased and decreased after SV and SAV, respectively. The acid secretion in response to insulin was increased only after SPV, while it was decreased after the other types of vagotomy. These results led to the condition that there might be no correlation between serum gastrin and acid secretory responses to feeding and insulin after various types of vagotomy.

Animals↗