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T Oohara

Publications and source records attributed to T Oohara.

At least 73 records · Page 4Linked to original sources
PubMed1990

Ventricular cells in culture from adult spontaneously hypertensive rats exhibit decreased growth.

We have investigated the growth characteristics of adult rat ventricular cells (ARVC) in culture from 8-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Protein synthesis in ARVC estimated from tritiated leucine uptake was augmented in both strains after exposure of cells to either norepinephrine or fetal bovine serum (FBS), but the response was significantly smaller in SHR than in WKY. A relative increase in the protein content of ARVC incubated with norepinephrine or FBS was also smaller in SHR than in WKY. These results demonstrate that SHR cardiac myocytes are not genetically growth-accelerated and show a decreased growth response to growth stimuli such as norepinephrine and serum during the adult period.

Aging↗
PubMed1989

Flat early cancers of the large intestine.

From January 1976 to December 1987, 37 early colorectal cancers of the flat type were treated. Thirty-four of them (91.9%) were not accompanied by adenoma, and were thought to have arisen de novo. There is indeed a de novo route of cancer development in the human large intestine, and cancers de novo merely show polypoid growth. Flat type cancers arising de novo tend to reach deeper layers at an earlier stage than polypoid-type carcinomas in adenoma. Of those with a diameter of less than 10 mm, only 40% stayed in the mucosa. Consequently, advanced cancers cannot be prevented by snare polypectomy alone. More attention should be directed to the discovery of small, flat, nonpolypoid cancers.

Aged↗
PubMed1989

Dual regulatory mechanisms of proton transport in rat papillary collecting duct cells in culture.

The regulation of proton transport and cytosolic pH was studied in rat papillary collecting duct (PCD) cells in culture using a pH-sensitive fluorescence probe, 2,7-bis-carboxyethyl-5,6-carboxyfluorescein (BCECF). Data were obtained from confluent monolayers grown on glass coverslips and dipped in a HCO3- -free medium, pH 7.40. The resting intracellular pH (pHi) was 7.16 +/- 0.03 (n = 20). When PCD cells had been acidified by pretreatment with NH4Cl, pHi immediately recovered toward the resting value. Two mechanisms participated in this recovery: a Na+-dependent mechanism which could be inhibited by amiloride (indicative of Na+-H+ exchanger) and a Na+-independent process (a proton ATPase). The pHi recovery from acid loading was inhibited by amiloride to about 55% of the control recovery (half-maximal effect at 100 microM). The rate of pHi recovery after the readdition of Na+ to a sodium-free medium exhibited saturation kinetics (half maximal rate at 28 mM). Dicyclohexylcarbodiimide (DCCD), an inhibitor of a plasma membrane proton ATPase, and the depletion of cellular ATP induced by 2 mM potassium cyanide (KCN) also partially inhibited the rate of pHi recovery after cell acidification with a NH4Cl load. When PCD cells were treated with 1 mM DCCD, amiloride almost completely inhibited pHi recovery. Amiloride and the removal of external Na+ had induced a gradual fall in pHi to a new resting value and rapidly recovered when Na+ was added. We conclude that PCD cells grown in culture have at least two proton transport mechanisms: a Na+-H+ exchanger and a plasma membrane proton ATPase. The kinetics of these processes can be reliably assessed by the pH-sensitive fluorescent probe, BCECF. Both the Na+-H+ exchanger and the plasma membrane proton ATPase may contribute to urinary acidification.

Adenosine Triphosphatases↗
PubMed1989

[Serial myocardial lactate metabolic changes after intracoronary thrombolysis in evolving myocardial infarction].

To ascertain whether early intracoronary reperfusion (less than 3 hours) preserves aerobic myocardial metabolism in acute myocardial infarction, serial changes in trans-cardiac lactate extraction after intracoronary thrombolysis were examined in 35 patients with acute anteroseptal myocardial infarction. Eight patients without intracoronary reperfusion served as controls. In the chronic phase, we also observed abnormally contracting myocardial segments as an index of infarct size and the regional ejection fraction as an index of chronic regional cardiac function. In the early reperfusion group (less than 3 hours; 15 cases), positive lactate extraction was restored; there were small abnormally-contracting segments and a high regional ejection fraction. However, the intermediate reperfusion group (3-5 hours; 10 cases) had sustained anaerobic lactate extraction, large abnormally-contracting segments and a low regional ejection fraction. The late reperfusion (greater than 5 hours; 10 cases) group showed apparent aerobic lactate extraction, but had large abnormally-contracting segments and a low regional ejection fraction. Thus, early reperfusion preserves aerobic lactate metabolism and good ventricular function in the chronic phase.

Heart Ventricles↗
PubMed1988

Minute cancers arising de novo in the human large intestine.

In order to search for the histogenesis and progression of colorectal cancer, the background mucosas of 18 patients with a single colorectal cancer, apart from familial adenomatosis coli, were studied by a step sectioning method. Three early minute cancers (3-5 mm in diameter) were detected in the apparently normal mucosa, and two cancers in the adenoma (focal cancer in adenomatous polyp). The three early cancers had no evidence of preexisting adenoma, so they were considered to be de novo cancers. In form they were depressed, flat, and slightly elevated. In humans, de novo cancer has an important significance in histogenesis and treatment of colorectal cancer. Clinically, it is also important to recognize the early phase of colorectal cancer in flat type as well as polypoid type.

Adenoma↗
PubMed1988

Intraoperative colonoscopy in the detection of nonpalpable colonic lesions--how to identify the affected bowel segment.

The development and widespread use of the colonic fiberscope has led to the identification of early colonic cancers which, being small and flat, are not palpable by intraoperative examination of the exterior of the intestine. Standard operation for cancer is required when snare polypectomy is insufficient, or when it is considered that the lesions would be resected incompletely by electrocautery. We report on the use of intraoperative colonoscopy in 11 patients to identify small lesions and to maintain an adequate distance from the lesions. Intraoperative colonoscopy allows lesions to be detected rapidly, safe operations, and a decrease in operation time.

Adenoma↗
PubMed1988

Lymphangioma of the large intestine. Report of a case.

Lymphangiomas of the large intestine have been reported more frequently since the development and widespread use of the colonic fiberscope. It is possible to endoscopically diagnose lymphangiomas because they are lustrous and smooth on the surface, pliable on compression, and half of them have a stalk or a waist at the base. Lymphangiomas of the colon and rectum under 20 mm in diameter can be safely resected by electrocautery, thereby avoiding unnecessary operation.

Colonic Neoplasms↗
PubMed1988

[Nutritional support in critically ill patients; with special reference to fat emulsion and carnitine].

Energy metabolism of fat emulsion was studied in rats with septic condition. The results indicate that fat emulsion was rapidly eliminated from the blood stream and metabolized readily even in such condition. Based on these findings, we have actively employed fat emulsion clinically as an energy source of septic patients. In septic rats, it was demonstrated that levels of carnitine decreased and that this decrease was based upon a decrease of synthesis. When carnitine was administered together with fat emulsion, the energy metabolism returned to approximately normal level. This reports also describes the absorption and utilization of orally administered fat in septic rats.

Animals↗
PubMed1987

Immunological cross-reactivity between beta-galactoside-binding lectins of vertebrates. Possible relationship of antigenicity to oligomeric structure.

Structural relationships among five beta-galactoside-binding lectins isolated from human, mouse and chick were studied using immunochemical methods. The lectins examined were human placenta lectin with a 14-kDa subunit (human 14K lectin), two types of mouse lectin (mouse 15K and mouse 16K lectin), and two types of chick lectin (chick 14K and chick 16K lectin). Five polyclonal antibodies raised against these lectins were used. Antibody to human 14K lectin cross-reacted with mouse 15K and chick 14K lectins. Antibodies to both mouse 15K and chick 14K lectins cross-reacted with human 14K and chick 16K lectins. Antibody to chick 16K lectin cross-reacted with mouse 15K lectin. An immunological relationship was not found between human 14K and chick 16K lectins, or between mouse 15K and chick 14K lectins. Mouse 16K lectin did not show any immunological relationship with any of the other lectins. A monoclonal antibody raised against chick 14K lectin cross-reacted with chick 16K lectin. These results cannot be explained simply in terms of phylogenic distance but suggest that vertebrate beta-galactoside-binding lectins can be classified into two structural groups on the basis of their antigenicities. One group, which is characterized as a monomer type, includes human 14K and chick 14K lectins. The other group, which is characterized as a dimer type, includes mouse 15K and chick 16K lectins.

Animals↗
PubMed1987

A clinicopathological study of post-bulbar duodenal ulcer--analysis of 6 cases and comparison to usual chronic duodenal ulcer.

We investigated the functional and morphological aspects of acid secretion in 6 patients with post-bulbar duodenal ulcer and compared the findings with the events of 40 patients with the usual chronic duodenal ulcer. The post-bulbar ulcer patients showed a much higher acidity, and a biphasic, prolonged acid secretion pattern, presumably representing an enhanced parietal cell function. Histological study of antrectomized specimens revealed that 4 of those with the post-bulbar ulcer had a small antrum in which the fundic gland area expanded distally. The proximal border of the pyloric gland area was within 4 cm of the pylorus. This would suggest the presence of a large parietal cell mass. On the contrary, however, there was no such instance in those patients with the usual duodenal ulcer. Hyperacidity, due to a large parietal cell mass and an enhanced parietal cell function, may play an important role in the pathogenesis of post-bulbar duodenal ulcer.

Adult↗
PubMed1987

Granulomas of the gut in Crohn's disease. A step sectioning study.

To investigate the distribution of granulomas in Crohn's disease, a step sectioning study of the surgically resected intestines was carried out. This study proved that granulomas in Crohn's disease are found in the seemingly uninvolved intestinal mucosa as well as in the affected mucosa. Granulomas in the apparently involved mucosa were close to the mucosal surface (less than 500 microns) and small (80 to 160 microns across), while in the affected mucosa they were farther away from the mucosal surface (more than 500 microns) and larger (more than 160 microns across). We emphasize that these small granulomas, namely microgranulomas, in the apparently uninvolved intestinal mucosa, are of great value in diagnosing Crohn's disease.

Adult↗
PubMed1987

A new model for production of chronic gastric ulcer by duodenogastric reflux in rats.

We have established an experimental model of chronic gastric ulcer, in rats which transection of the lower horizontal portion of the duodenum and anastomosis of the forestomach to the upper part of the jejunum caused regurgitation of all duodenal juice into the stomach. After 3, 6, 12, and 30 wk, all treated rats developed an ulcer in the prepyloric region on the lesser curvature of the stomach. More than half of the antrum was finally involved in the ulcer. Histologic studies revealed chronic ulcers quite similar to human ones. As a control series, transection at the pylorus failed to produce an ulcer. Although many papers have appeared regarding the experimental production of chronic gastric ulcer, most of the studies reported have applied chemicals, drugs, or mechanical injury to the gastric mucosa. Our model produced chronic regurgitation of duodenal juice as a natural phenomenon, and uniformly resulted in ulcer formation. Intragastric total bile acid concentrations were significantly elevated in the reflux group. Serum gastrin levels, the thickness of the fundic mucosa, and the height of fundic gland were also significantly increased. Thus, the detergent action of bile acids and the increased acid secretion were assumed to play an important role in ulcer formation. Further studies using this model are warranted on the pathogenesis of chronic peptic ulceration.

Animals↗
PubMed1985

[An operative case of spermatic cord rhabdomyosarcoma--with a review of similar cases in Japan].

A 17-year-old Japanese boy was admitted with the complaint of painless, progressive enlargement of the left scrotal contents during the preceding two months. The tumor was firm and nontender without transillumination. Orchitectomy with high ligatation of the spermatic cord was performed. The tumor, weighing 13.1 g, was gray, solid, located at the distal part of the spermatic cord, and separated from the testis and epididymis. The pathological diagnosis showed left spermatic cord rhabdomyosarcoma of the combined embryonal and alveolar type. All of the retroperitoneal lymph nodes dissected were negative for metastasis. The patient was treated with actinomycin D and vincristin postoperatively, and is well three years after the operation. Ninety-two cases of intrascrotal rhabdomyosarcoma reported in Japan are reviewed.

Adolescent↗
PubMed1984

Clinical diagnosis of minute gastric cancer less than 5 mm in diameter.

When 58 minute gastric cancers less than 5 mm in diameter from 55 patients were classified into 22 of the single group (minute gastric cancer alone) and 36 of the multiple group (associated with other large gastric cancers), the preoperative correct diagnostic rate by x-ray was 22.7% and 11.1% in the single group and in the multiple group, respectively, with a total rate of 15.5%. The diagnostic rate by endoscopy, aided by endoscopic biopsy, was 95.5%, 13.9%, and 44.8%, respectively. Therefore, it appears that endoscopy and endoscopic biopsy are most efficient diagnostic tools for the detection of such minute gastric cancers. Since the detection of the depressed type (IIc) of minute gastric cancers is considered most significant because of their frequent submucosal invasion, their characteristic endoscopic findings are emphasized: (1) irregular and polygonal shape, (2) distinct depression, (3) clear demarcation, (4) nodular margins, and (5) moth-eaten appearance and abrupt thinning of the mucosal folds.

Biopsy↗