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Biomedical subjects

T Shiratori

Publications and source records attributed to T Shiratori.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effect of parathyroid hormone-like peptides on 25-hydroxyvitamin D-1 alpha-hydroxylase activity in rodents.

The role of vitamin D metabolism in the humoral hypercalcemia of malignancy syndrome (HHM) is unclear. We studied in vivo and in vitro effects of synthetic parathyroid hormone-like peptides (PTH-LPs) on rodent renal 25-OHD-1 alpha-hydroxylase activity. Infusion of mice with PTH-LP-(1-36) at 10 pmol/h for 12 and 24 h showed significant (429 +/- 139% and 937 +/- 413%, respectively) stimulation of control enzyme activity. Infusion for 36 h demonstrated diminution of activity to levels nearer to the unstimulated state (228 +/- 36% of control). In that maximal activity was observed after 24 h of infusion, we examined 1 alpha-hydroxylase activity after variable dosages of PTH-LP-(1-36) at this time point. Animals infused with PTH-LP-(1-36) at dosages of 2.5, 10, and 30 pmol/h for 24 h demonstrated 1 alpha-hydroxylase activities of 0.71 +/- 0.12, 4.74 +/- 2.09, and 9.91 +/- 1.01 ng.mg protein-1.20 min-1 (means +/- SD), respectively, all significantly greater than control activity (0.51 +/- 0.20 ng.mg protein-1.20 min-1). PTH-LP-(1-36) and PTH-LP-(1-74) were comparable in potency to bovine (b)PTH-(1-34) in stimulating 1 alpha-hydroxylase. Direct in vitro incubation of PTH-LP-(1-36) with renal slices resulted in stimulation of 1 alpha-hydroxylase activity up to 200% of control levels, comparable to that seen with equimolar concentrations of bPTH-(1-34).(ABSTRACT TRUNCATED AT 250 WORDS)

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1990

Renal 25-hydroxyvitamin D-1 alpha-hydroxylase activity and mitochondrial phosphate transport in Hyp mice.

The Hyp mouse is a homologue of the X chromosome-linked human disease, familial hypophosphatemic rickets (FHR). In FHR, reduced renal tubular brush-border membrane transport of phosphate results in hypophosphatemia and rickets. Both humans with FHR and Hyp mice have abnormal regulation of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase), a mitochondrial enzyme found in proximal renal tubular cell epithelia, the apparent site of defective brush-border membrane phosphate transport. No common pathophysiology for these defects has been demonstrated. We hypothesized that phosphate transport may be present in renal mitochondria from Hyp mice and that its regulation may be deranged in parallel with the mitochondrial 1 alpha-hydroxylase. Using inhibitor-stop techniques described for measurement of phosphate transport in liver mitochondria, we examined mitochondria in normal and Hyp mouse kidney and found them to be comparable. We performed manipulations known to alter 1 alpha-hydroxylase differentially in normal and Hyp mice, i.e., phosphorus deprivation and phosphorus loading, and found no effect on mitochondrial phosphate transport. We also subjected Hyp and normal mice to calcium and vitamin D deprivation; this maneuver resulted in no significant changes in mitochondrial phosphate transport in Hyp or normal mice but confirmed the earlier observation that 1 alpha-hydroxylase activity is stimulated to a greater degree in normal mice than Hyp mice after this diet. Furthermore, administration of 1,25-hydroxyvitamin D3 depresses 1 alpha-hydroxylase activity in mitochondria from both normal and Hyp mice but has no effect on mitochondrial phosphate transport. We conclude that the mechanism of abnormal vitamin D metabolism in Hyp mice is not related to a primary defect in renal mitochondrial phosphate transport.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1990

[Experience of surgical therapy of pyothorax in the pleural fistula of the bronchi and esophagus due to esophageal cancer].

The esophagectomy and total left pneumonectomy were carried out in a 53-year-old male who had developed pyothorax in the pleural fistula of the bronchi and esophagus due to esophageal cancer, and then reconstruction of the esophagus by route of the anterior thoracic wall was performed using stomach tube biphasically. The postoperative course was favorable, and oral intake was possible, and his physical condition recovered as the patient could repeat stopping out from hospital while he died by pneumonia after 7 months. The remote metastasis or metastasis to the mediastinal lymph-node were not noted by autopsy. It is considered that there are cases having indication for active resection among A3-esophageal cancers.

Bronchial Diseases↗
PubMed1989

Nucleotide sequence of the Thiobacillus ferrooxidans chromosomal gene encoding mercuric reductase.

The nucleotide sequence of the Thiobacillus ferrooxidans chromosomal mercuric-reductase-encoding gene (merA) has been determined. The merA gene contains 1635 bp, and shares 78.2% and 76.6% sequence homology with the transposon, Tn501, and plasmid R100 merA genes, respectively. From the sequence, a 545-amino acid (aa) polypeptide was deduced, and comparison with those of Tn501 and R100 revealed 80.6% and 80.0% homology, respectively, at the aa sequence level. Divergence among the three merA aa sequences was clustered within a specific region (aa positions 41-87). By analysis of codon usage frequency, it is speculated that the T. ferrooxidans merA gene originated from Tn501, R100, or a common ancestral gene, but not from T. ferrooxidans itself.

Acidithiobacillus thiooxidans↗
PubMed1989

A case of hemangioendothelioma of the small intestine.

An 81-year-old female was admitted to hospital with anemia and abdominal discomfort, however, various pre-operative diagnostic work-ups for the gastro-intestinal tract revealed no significant change. At the time of surgery, a small intestinal tumor was discovered by means of endoscopy and seven centimeters of ileum was radically resected. The tumor was subsequently diagnosed histopathologically as hemangioendothelioma. The patient recovered quickly and now, 6 years later, has had no sign of tumor recurrence. The incidence of this tumor is reportedly less than 3 per cent of all tumors found in the small intestine and the prognosis of this tumor in the small intestine is poor. A five-year-survival rate can be referred to only 33.3 per cent of the reported cases.

Aged↗
PubMed1989

A case of intestinal obstruction due to a hernia traversing the lesser sac.

A case of a hernia traversing the lesser sac with a primary defect in the greater omentum and a secondary defect in the lesser omentum is reported herein. This type of internal hernia is extremely rare and we have found only three other reported cases apart from our case. All four cases in whom this type of hernia occurred were young people. The general manifestation resembles acute intestinal obstruction and a plain radiograph shows obstruction of the upper small intestine. An erect lateral view of the abdomen often shows the anatomical location more clearly. Bowel resection was performed in two cases and all of the four reported cases recovered uneventfully.

Adult↗
PubMed1989

Cloning and expression of Thiobacillus ferrooxidans mercury ion resistance genes in Escherichia coli.

A search of various domestic isolates of Thiobacillus ferrooxidans revealed that some were fairly resistant to mercury ion. A proportion of mercury-resistant clones were able to volatilize mercury, and their corresponding gene was localized not in the plasmid DNA but in chromosomal DNA. This mercury ion resistance gene was cloned in Escherichia coli. E. coli carrying the recombinant plasmid was able to grow in the presence of more than 40 micrograms of HgCl2 per ml. Deletion analysis of the recombinant plasmid showed that the entire coding sequence of the mercury ion resistance gene was located within a 2.3-kilobase fragment of the chromosomal DNA from strain E-15. At least two polypeptides (molecular mass, 56 and 16 kDa, respectively) were coded by this fragment.

Bacterial Proteins↗
PubMed1989

Gastric emptying in patients with gastric and duodenal ulcer.

Gastric emptying was measured in patients with proximal gastric, distal gastric and duodenal ulcers using a radioisotopic method. Gastric emptying was rapid in patients with proximal gastric ulcer, and was considered to be due to accelerated proximal evacuation. However, emptying was delayed in patients with distal gastric ulcer, and was considered to be due to reduced emptying in the antrum. On the other hand, rapid emptying seen in duodenal ulcer patients was considered to be due to accelerated emptying in both the proximal stomach and the antrum. Gastric emptying in the healing stage was closer to that in healthy subjects than in patients with active-stage ulcer.

Duodenal Ulcer↗
PubMed1988

Brain eicosanoid levels in spontaneously hypertensive rats after ischemia with reperfusion: leukotriene C4 as a possible cause of cerebral edema.

The relation of brain eicosanoids to progression of cerebral edema was studied in stroke-resistant spontaneously hypertensive rats subjected to incomplete global brain ischemia induced by bilateral occlusion of the common carotid arteries. Thromboxane B2 and 6-keto prostaglandin F1 alpha levels were significantly elevated 5 minutes after reperfusion but returned to control levels by 30 minutes. In contrast, leukotriene C4 levels increased 2 hours after bilateral common carotid artery occlusion and peaked 30 minutes after reperfusion, with higher levels persisting until 60 minutes after reperfusion. Cerebral ischemia was accompanied by cerebral edema early after reperfusion. The edema correlated with increased leukotriene C4 levels. That the increased brain water content was causally related to an increase in leukotriene C4 was supported by results obtained following administration of the 5-lipoxygenase inhibitors ONO-LP-016 and AA-861. Both inhibitors suppressed the increased leukotriene C4 and brain water contents after reperfusion. Our results indicate that leukotriene C4 is closely associated with an induction of ischemic cerebral edema.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

New additional operation for the prevention of the gastric stasis after selective gastric vagotomy with antrectomy.

In order to prevent postoperative gastric stasis, we devised and tested the following improvements in the selective gastric vagotomy with antrectomy. (1) The gastroduodenostomy was made so as to have an acute angle to the longitudinal axis of the remnant stomach, and (2) the downward traction being exerted on the remnant stomach by the transverse colon was eliminated by dissecting the greater omentum, and then (3) the posterior wall of the corpus on the lesser curvature side was fixed to the stump of the hepatogastric ligament, and the posterior wall of the corpus on the greater curvature side was fixed to the retroperitoneum inferior to the pancreas. By these procedures, the corpus was maintained in a position superior to the anastomosis. These operative procedures resulted in preventing the gastric stasis after the start of oral feeding. The two patients on whom this operation was performed have been followed up for 3 to 4 months since the operation, and neither of them has had any complaint of gastric stasis, such as anorexia or a feeling of heaviness of the stomach.

Follow-Up Studies↗
PubMed1987

Oncofetal expression of glutathione S-transferase placental form in human stomach carcinomas.

The content of glutathione S-transferase placental form (GST-pi) was immunohistochemically analyzed in 100 cases of human stomach carcinoma of various histological types and compared with the content in the stomach mucosa of the human fetus, infant and adult. High levels of GST-pi content were demonstrated in all stomach carcinomas except for signet ring cell carcinomas. High levels were also present in surface mucous cells and glandular cells of the stomach from a fetus aged 18 weeks, whereas only the parietal cells of fundic glands in the adult stomach showed slight staining for GST-pi. These results indicate that the phenotypic expression of GST-pi in human stomach carcinoma is oncofetal in character.

Adenocarcinoma↗