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Biomedical subjects

K Okita

Publications and source records attributed to K Okita.

At least 19 recordsLinked to original sources
PubMed1992

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area.

To assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (31P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSAmax) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J.cm-2 CSAmax for 1 min and an increment of 1 J.cm-2 CSAmax every minute to the point of muscle exhaustion. A series of measurements of 31P-MRS were performed every minute. The CSAmax was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm2, P less than 0.05]. The absolute maximal exercise intensity (J.min-1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J.min-1.cm-2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5'-diphosphate to drive adenosine 5'-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J.min-1.cm-2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effects of secretin on bile production in two kinds of cholestatic models by choledocho-caval fistula and bile duct ligation in rats.

Secretin is known to stimulate bile flow from the bile duct epithelium. To investigate the effects of secretin in cholestasis, we studied the response of the bile flow and the excretion of biliary components to secretin using two cholestatic models with or without damage to the bile duct epithelium. The model without bile duct epithelial damage was a choledocho-caval (CC) fistula over a 24-hour period, and the model with bile duct damage was a bile duct ligation over a 48-hour period. Secretin was administered by intravenous infusion for 30 minutes and bile was collected for 120 minutes. Controls were given saline similarly. The bile flow and biliary bicarbonate excretion rate were significantly increased after secretin infusion in the CC fistula rats when compared with the control rats, but no stimulation by secretin was observed in the ligated rats. These data indicate that secretin-induced bile production was enhanced under cholestatic conditions with no bile duct epithelial disturbance.

Animals↗
PubMed1992

The incidence of cardiac events in Japanese men with atypical or nonanginal chest pain: a prospective study on the significance of exercise testing.

The incidence of cardiac events in Japanese men (mean age 54 +/- 10 years) with atypical or nonanginal chest pain was assessed prospectively. Three groups of patients, those with typical angina (TA; n = 134), those with atypical angina (AA; n = 192), and those with nonanginal chest pain (NA; n = 311) were studied with regard to cardiac events (cardiac death or nonfatal myocardial infarction), risk factors, and results of exercise testing. The total cholesterol and high-density lipoprotein-cholesterol levels were significantly different among the three groups, but no differences were observed for other risk factors. The incidences of cardiac events were 8.5%, 2.2%, and 1.3% in the TA, AA, and NA groups, respectively (p less than 0.05) during 3.2 +/- 1.5 years. Significant ST segment changes were observed in 70.1%, 25.5%, and 18.0% of the patients in the TA, AA, and NA groups, respectively, at the time of enrollment. The risk ratio for cardiac events in a positive exercise test was 1.7 (difference not significant) for the TA group and 6.1 (p less than 0.05) for the others combined (AA and NA groups). The risk ratio adjusted for risk factors (Cox model) was 2.2 (difference not significant) for the TA group and 4.9 (p less than 0.05) for the AA and NA groups combined. In conclusion, the incidence of cardiac events in those with AA or NA chest pain was relatively low in Japan, but the independent prognostic significance of positive exercise testing was demonstrated in this group of patients.

Adult↗
PubMed1992

Application of ultrasonic probes prior to endoscopic resection of early gastric cancer.

The development of a new strip biopsy technique for endoscopic mucosectomy utilizing endoscopic saline injection and a double-channel endoscope permits the safe and simple resection of superficial type early gastric cancer which has been difficult to perform with conventional polypectomy techniques. Preresection assessment of the depth of invasion and postresection assessment of efficacy are important with regard to treatment of early gastric cancer, but conventional endoscopic ultrasonography employed for this purpose requires special equipment and involves intricate procedures. An ultrasonic probe which can be used endoscopically has recently been developed and is currently in the trial stage. The authors have conducted studies with respect to a 7.5 MHz radial scanning type Miniature Ultrasonic Probe as well as a 20 MHz manual linear scanning type Sonoprobe System. Experimental studies indicated that the former type is capable of delineating postresection ulcers, while the latter permitted delineation of tumors as hypoechoic images in 9 of 11 cases of early gastric cancer.

Adenocarcinoma↗
PubMed1992

Detection of proliferating hepatocytes by immunohistochemical staining for proliferating cell nuclear antigen (PCNA) in patients with acute hepatic failure.

This study evaluated whether liver regeneration could take place after massive or submassive necrosis of liver cells in 25 patients with several kinds of hepatic failure by immunohistochemical staining for proliferating cell nuclear antigen (PCNA). PCNA positivity was significantly higher (P less than 0.01) in the patients who survived than in the patients who died. Furthermore, PCNA-positive hepatocytes were recognized diffusely in the lobule of the liver in survivors. There was positive correlation between PCNA positivity and plasma concentration of AFP (alpha-fetoprotein), (r = 0.77, P less than 0.01). These results show that liver regeneration could take place after massive necrosis of liver cells in survivors from acute hepatic failure and that immunohistochemical staining for PCNA is useful for prognostic evaluation.

Antibodies, Monoclonal↗
PubMed1992

Analysis of lymphoid follicles in liver of patients with chronic hepatitis C.

Using immunohistological methods, we studied the lymphoid follicles in liver biopsy specimens obtained from patients with chronic hepatitis C(CH-C) to determine whether they represented an autoimmune manifestation. In 84 specimens obtained by liver biopsy from 76 patients positive for C-100 antibody, we assessed the presence or absence of lymphoid follicles within the portal areas, and then compared the clinical and immunohistological profiles of the two groups defined on this basis. There were no significant differences in the serological and clinical profiles of the two groups, but the T4:T8 cell ratio within the portal areas differed significantly. A T4:T8 cell ratio > 1.0 was more common in the specimens containing lymphoid follicles. This finding resembled the distribution of T cell subpopulations in the portal areas of patients with autoimmune hepatitis, and suggested that lymphoid follicles may be worth investigating to elucidate the relationship between chronic hepatitis C and autoimmune hepatitis.

Autoimmune Diseases↗
PubMed1992

Beneficial effect of stopping smoking on future cardiac events in male smokers with previous myocardial infarction.

UNLABELLED: We assessed the effect of stopping smoking on future cardiac events (cardiac death and non-fatal myocardial infarction (MI)) in 90 male smokers with previous MI by a prospective follow-up study. At the time of enrollment, the patients were divided into 2 groups according to their current smoking status (Group A: those who had stopped smoking (n = 60), and Group B: those who were still smoking (n = 30)). Follow-up was performed prospectively by annual postal questionnaires. During the mean follow-up period of 3.1 +/- 1.4 years, 13 cardiac events (11 cardiac deaths and 2 cases of non-fatal MI) occurred in the 87 evaluable patients. The cardiac event rates in Groups A and B were 8.5% and 28.6%, respectively, and the relative risk was 3.4 (Group A vs B, p less than 0.05) by univariate analysis. The relative risk using multivariate analysis (Cox) was also statistically significant (3.1, p less than 0.05). HDL-cholesterol was significantly lower in Group B than in Group A, but other coronary risk factors apart from smoking were not significantly different between the two groups. At the end of the follow-up period, 89.8% of the patients in Group A remained nonsmokers and 21% of the patients in Group B had stopped smoking. CONCLUSION: Stopping smoking significantly reduced the risk of future cardiac events in male smokers with previous MI. This prospective follow-up study demonstrated that a significant reduction in the risk of future cardiac events could be achieved by stopping smoking in this group of patients.

Adult↗
PubMed1992

[Proton pump inhibitor for maintenance therapy of peptic ulcer].

The strategy for peptic ulcer therapy has been changing with the clinical application of the gastric proton pump inhibitor (PPI). In Japan, Miyoshi et al and Takemoto et al reported an earlier reepithelialization of peptic ulcer with omeprazole (OME) or lansoprazole (LAN) than famotidine (FAM). Miyoshi et al also reported that there was no significant difference between OME and FAM in ulcer relapse rate during a one year follow-up period. Therefore, there were two problems. One is application of PPI for prevention of ulcer relapse, and the other is the more accurate diagnosis of ulcer healing. Application of PPI for maintenance therapy is not yet realized in Japan, but, Lauritsen et al had already reported on the efficacy and safety of OME, 20 mg, three days a week and 10 mg, daily in prevention of duodenal ulcer relapse. Reepithelialization (red scar) is already established as a starting point of maintenance therapy, and from Miyake's report, a white scar is believed a favorable (non relapsing) end point.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1992

[Immunohistological study on the expression of proliferating cell nuclear antigen (PCNA/cyclin) in human colorectal lesions].

The purpose of this study was to clarify the significance of immunohistological staining for PCNA/cyclin in human colorectal lesions. Our results: The PCNA-positive cells existed at the bottom of colonic tubuli in the normal and hyperplastic conditions. In the neoplastic lesions, however, the positive cells were existed at the relatively surface of the mucosa (chi 2: P less than 0.01) and distributed irregularly from the bottom to the top of carcinoma tissue. These results suggested that immunohistological staining for PCNA would specifically detect the cell proliferation and be beneficial for practical use and clinical application of the diagnosis of the colorectal lesions.

Adenocarcinoma↗
PubMed1992

[Nutritional treatment of hepatocellular carcinoma].

We investigated the relationship between the growth of HCC and nutrition, especially amino acids, and reconsidered the clinical application of amino acid imbalance. At first, rat chemical hepato-carcinogenesis was performed to investigate whether Aminoleban EN stimulates or restrains the occurrence of HCC. 2-Acetyl-amino-fluorene containing diet was administered intermittently according to Epstein's method. Rats were divided into two groups; group 1 was fed on Aminoleban EN containing diet and group 2 on a basal diet. There was no significant difference between the survival rate in the two groups. The average body weight of group 1 was significantly higher than that of group 2. The rats were sacrificed at the 25th week. All 11 rats of group 1 had no liver tumor, but 2 of 17 rats of group 2 had liver tumors, including a HCC and cholangiocellular carcinoma. The incidence of the liver tumor was significantly different between the two groups. Aminoleban EN could inhibit rat liver carcinogenesis, so it is considered to be a desirable nutritional product for LC patients from the stand point of cancer prevention. Secondly, the composition of amino acid was studied on HCC and surrounding tissue. There was no significant difference of Val, Leu, Leu, Phe, Tyr, Met and Fischer ratio between HCC and surrounding tissue.

Amino Acids↗
PubMed1991

Role of epidermal growth factor in protection and repair of gastric mucosal injury.

A role of epidermal growth factor (EGF) in protection and repair of gastric mucosal injury caused by p.o. administration of 0.6 N HCl was investigated in male Wistar rats. Previous to the study on the role of EGF in gastric mucosal protection and repair, changes of gastric mucosal EGF level was determined sequentially by RIA for 180 min after treatment with 0.6 N HCl and intraperitoneal injection of recombinant hEGF. Concentration of incorporated hEGF into the gastric mucosa reached the peak level at 30 min after injection of hEGF. On the other hand, the gastric endogenous EGF level fell remarkably immediately after treatment with 0.6 N HCl. Successively, an association with the mucosal levels of incorporated hEGF and gastric ulcer indices was investigated in the rats in which hEGF was injected intraperitoneally 30 min prior to or at the same time as oral administration of 0.6 N HCl. In conclusion, pretreatment with hEGF protected significantly against gastric mucosal injury with 0.6 N HCl, whereas simultaneous administration of hEGF could not protect against mucosal injury but indicated possible stimulation of the repair process from acute gastric mucosal damage.

Animals↗
PubMed1991

Evaluation of peptic ulcer healing with a highly magnifying endoscope: potential prognostic and therapeutic implications.

Gastric and duodenal ulcer healing and scarring were evaluated with a highly magnifying endoscope. The appearance of scar was classified into three types: Sa, with a depression at the center; Sb, with a pattern of regenerated mucosa reaching the center; and Sc, with a uniform pattern throughout. The relationship between regenerative mucosal patterns and histologic findings of biopsy specimens was investigated in 58 patients with gastric ulcer. Mucosal regeneration was sufficient in 26.7% of patients with Sa pattern, 79.2% of patients with Sb pattern, and 100% with Sc pattern. From prospective endoscopic follow-up observations, the relationship between endoscopic findings of ulcer scars and ulcer relapses was investigated in 80 patients with gastric ulcer and 56 patients with duodenal ulcer. As a result, patients who completed the cycle of ulcer healing from Sa pattern through Sb to Sc patterns had rarely relapse. In contrast, patients with a Sa pattern of mucosal scar showed a high rate of recurrence: 88.8% for gastric ulcer, and 88.0% for duodenal ulcer. Our method of evaluation of gastric and duodenal ulcer healing with a highly magnifying endoscope may have important prognostic and therapeutic implications. It may indicate a population of patients (with Sa scarring pattern) with a high risk of ulcer recurrence and therefore requiring prolonged prophylactic treatment.

Cicatrix↗