Biomedical subjects

T Misawa

Publications and source records attributed to T Misawa.

At least 73 records · Page 4Linked to original sources

PubMed1991

The direct contractile effect of gastrin releasing peptide on isolated gastric smooth muscle cells of the guinea pig.

Smooth muscle cells isolated from the gastric muscle layers of the guinea pig were used to determine whether gastrin releasing peptide (GRP) can cause contraction by exerting a direct action on muscle cells. In addition, the inhibitory effect of 8-( N,N-diethylamino )-octyl-3,4,5-trimethoxybenzoate hydrochloride ( TMB-8 ), an inhibitor of intracellular Ca2+ release, and verapamil, a Ca2+ channel blocker, on the GRP-induced contraction of gastric smooth muscle cells were examined. GRP elicited a contractile response of gastric muscle cells in a dose-dependent manner. The ED50 was 13 pM. TMB-8 significantly inhibited the contractile effect of GRP in gastric muscle cells. These results demonstrate the direct action of GRP on the gastric smooth muscle cells of the guinea pig, and the importance of Ca(2+)-release from intracellular calcium, stores in the contractile response to GRP.

Animals↗

PubMed1991

Preoperative evaluation of gastric cancer by endoscopic ultrasound.

The preoperative use of endoscopic ultrasound was evaluated in 74 patients with confirmed gastric cancer. It was used in diagnosing the depth of invasion in the gastric wall, the infiltration to the adjacent organs, and the involvement of the perigastric lymph nodes. Results were compared with histological findings in resected specimens. Accuracy in staging gastric cancer using the T grade of the 1987 TNM system was 81.1% (60 of 74 patients). Endoscopic ultrasound provided excellent results compared with computed tomography and conventional ultrasound, particularly in evaluating perigastric lymph node metastasis and direct infiltration to the adjacent organs. The success rate in detecting lymph node metastasis was 50% (11 of 22 patients); the accuracy in diagnosing direct infiltration to the adjacent organs was 60% (three of five patients). This technique is useful in diagnosing malignant invasion and lymph node metastasis of gastric carcinomas but requires further refinement for use in diagnosing the disease itself. Its preoperative use is recommended for establishing surgical and other treatment plans, as well as in predicting the prognosis of gastric cancer.

Gastroscopy↗

PubMed1991

Scirrhous carcinoma of the stomach versus hypertrophic gastritis: findings at endoscopic US.

To differentiate scirrhous carcinoma from hypertrophic gastritis, 16 patients with scirrhous carcinoma of the stomach and seven patients with hypertrophic gastritis were examined with endoscopic ultrasonography (US) between August 1987 and October 1990. US images of the normal gastric walls of 16 patients with gastric ulcers served as controls. Characteristic features of scirrhous carcinoma included an irregular hypoechoic enlargement of the third (submucosa) and fourth (muscularis propria) layers. The mean thickness of the third and fourth layers was increased sixfold and threefold, respectively, compared with thickness in healthy subjects. In the patients with scirrhous carcinoma, the mucosal layer remained normal in appearance at US, and it was possible to distinguish the five-layer structure of the gastric wall. These findings were prospectively correlated with histopathologic findings in the resected specimens. In contrast, only the mucosal layer was thickened in cases of hypertrophic gastritis. Recognition of these patterns at US can aid in the differential diagnosis of scirrhous carcinoma and such benign diseases as hypertrophic gastritis with a thickened gastric wall.

Adenocarcinoma, Scirrhous↗

PubMed1991

Ventricular wall motion and NE release in post-ischemic reperfused myocardium.

To clarify the relationship between post-ischemic myocardial dysfunction and local cardiac sympathetic nerve function, we measured regional myocardial length and norepinephrine (NE) release during sympathetic nerve stimulation in 32 mongrel dogs. Coronary occlusion was produced by balloon occluder for 15 min and reperfused for 60 min. Dogs were divided into 3 groups as follows; Group 1 (n = 14): Sympathetic nerve stimulation, Group 2 (n = 9): Pre-treatment with yohimbine hydrochloride (0.2 mg/kg) and sympathetic nerve stimulation, Group 3 (n = 9): Exogenous NE administration. Sympathetic nerve stimulation or NE infusion were performed before occlusion and after reperfusion. In group 1, the extent of the increase in systolic shortening during sympathetic nerve stimulation (delta - shortening) lowered at 5 min after reperfusion and augmented progressively. But, delta-shortening at an early reperfusion period did not reduce in group 2 and 3. NE release from the ischemic myocardium decreased in group 1 and did not recover for 60 min. When the cardiac sympathetic nerve was denervated with 90% phenol solution, NE release further decreased in group 1. On the other hand, NE release did not decrease in group 2. These results indicate that the response to sympathetic nerve stimulation decreased in post-ischemic reperfused myocardium and this was due to diminished NE release. It was considered that sympathetic nerve conduction was not completely impaired in post-ischemic myocardium and pre-synaptic alpha-2 receptor mediated negative feedback mechanism would play an important role in these diminished NE release.

Animals↗

PubMed1991

[Effects of video games on visual function in children].

Health effects of video games were examined with a questionnaire survey and an experimental study. In the survey, age, sex, playing time with video games in a day, viewing distance between the eyes and the television screen, subjective symptoms of eye strain, and changes of visual acuity were investigated in 2,034 male and 2,321 female primary school children. In the experimental study, the visual loads of a one-hour word processing task and a video game were compared with various indices, such as critical flicker fusion, near point distance, blinking counts, eyeball movement, pupillary reflex and subjective fatigue symptoms in ten healthy male college students. The results of this study were as follows: 1) The viewing distance between the eyes and the TV screen was shorter for video games than for watching TV programs. 2) The rate of complaints related to eye strain in children who played video games over 120 min per day was significantly higher than that of other children. 3) The eye movements during video games were more rapid and frequent than those during conventional VDT work. 4) A decrease in CFF value and an extension of near point distance and an increase in subjective fatigue symptoms were demonstrated for both the word processing task and the video game. No significant differences were observed between the above two experimental conditions. This suggests that the visual loads for video games are similar to those for VDT work. These findings suggest that regulating the playing times to 60 minutes or less per day is necessary to prevent negative health effects in children.

Asthenopia↗

PubMed1991

[The effects of prenatal triphenyltin exposure on learning and development in the rat].

The toxicity of prenatal triphenyltin (TPT) exposure was studied in THA rats. Doses of 0 (control), 4 or 8 mg/kg/day of TPT were administered to pregnant rats from day 6 to day 20 of gestation by gastric intubation. In dams, the body weight of the 8 mg/kg group was significantly lower than that of control group, and 2 of 4 rats died on the expected day of delivery. In offspring, little effect of TPT on body weight, pinna detachment, incisor eruption, eye opening, surface righting, cliff avoidance, pivoting and negative geotaxis was found in either the 4 mg/kg or 8 mg/kg groups. In the Sidman avoidance test, the avoidance rate of the TPT groups was lower than that of the control group, and significant differences were found in the female groups. In a reversed test on the water E-maze test, the swimming time to the goal and the number of errors were increased in the TPT groups. These results suggest that prenatal TPT administration disrupts the learning acquisition of rats.

Animals↗

PubMed1991

[Induction of experimental splenomegaly with portal hypertension in rats with liver cirrhosis].

Liver cirrhosis was induced in rats by administering thioacetamide (TAA), and portal hypertension was maintained for at most 35 weeks to study the influence of portal hypertension on the weight of spleen and splenic tissues. TAA was intraperitoneally injected at dose of 200 mg/kg three times a week. The portal pressure was elevated and the weight of the spleen increased with the progression of hepatic fibrosis due to TAA. Liver cirrhosis was obviously observed after TAA was administered 60 times. The maximum ratio of the weight of the spleen to body weight in the group administered TAA was higher by 4.08 times than that in the control group. In all 49 rats used in the experiment there was a high correlation (r = 0.930, p less than 0.01) between the portal pressure and the ratio of spleen to body weight. Histological observation revealed that the red pulp tended to be enlarged, while the white pulp tended to be reduced, with increases in portal pressure and weight of the spleen. It also histologically revealed an increase in the splenic sinus-like structure, narrowing of the splenic cords, fibrosis due to reticular cell proliferation in the red pulp and fibrosis around the central artery in the white pulp. These histological changes in rats were similar to the histological findings of splenomegaly accompanying portal hypertension in humans. This suggests that the animal model prepared in the present experiment is useful as a model of splenomegaly due to portal hypertension.

Animals↗

PubMed1991

Effects of combination therapy with pirenzepine and famotidine on tetragastrin-stimulated gastric secretion in humans.

To determine the combined effects of the H2-receptor antagonist famotidine (FAM) and M1-receptor antagonist pirenzepine (PZ) on tetragastrin-stimulated acid production, 10 mg of FAM was intravenously injected into 6 healthy volunteers, alone and in combination with 20 mg of PZ. Physiologic saline was administered separately for control purposes. Compared with physiologic saline, both FAM and the FAM + PZ combination significantly reduced gastric secretion, acidity, acid output, and pepsin secretion. Concomitant use of PZ significantly enhanced FAM-induced reduction of overall gastric secretion, but did not enhance decreases in acid output, acidity, or pepsin secretion. These results indicate that combination therapy with intravenous FAM and PZ may be more useful than monotherapy with FAM in the treatment of gastroduodenal bleeding.

Adult↗

PubMed1991

Doppler echocardiographic assessments of left ventricular diastolic filling in patients with amyloid heart disease.

Twenty-eight patients with amyloid heart disease, 9 with primary and 19 with familial amyloidosis, were examined by Doppler echocardiography to characterize transmitral flow velocity patterns and to assess restrictive ventricular hemodynamics. Six of the 28 patients had restrictive ventricular physiology, and the remaining 22 did not. Patients with a restrictive filling process had marked ventricular wall thickening with depressed fractional shortening. The transmitral flow velocity patterns in patients with restriction were characteristically manifested by the increased peak flow velocity and shortening of rapid diastolic filling, which was associated with a reduced flow velocity in atrial systole. In the 22 patients without restriction, the left ventricular filling patterns were subclassified as 1) filling patterns with the prolonged isovolumic relaxation time and reduced early diastolic filling, as well as enhanced atrial contribution to ventricular filling (16 patients with mild echocardiographic abnormalities), 2) normal filling patterns with normal echocardiograms (4 patients), and 3) normal filling patterns, with moderate ventricular wall thickening (2 patients). These findings suggested that restrictive ventricular hemodynamics can be characterized by the transmitral velocity pattern and that patterns of left ventricular diastolic filling are markedly varied depending on the magnitude of myocardial amyloid deposition in patients with amyloid heart disease.

Adult↗

PubMed1991

A case of extragenital choriocarcinoma in the jejunum.

A case of extragenital choriocarcinoma which produces human chorionic gonadotropin (HCG) in the small intestine of a 48-yr-old Japanese women is reported. Only seven such cases have been reported. The patient complained of postprandial upper abdominal pain and vomiting of 5 months' duration. Nine years before, right upper lobectomy was performed because of lung undifferentiated carcinoma. Double-contrast examination of the small intestine showed irregular ulceration in the lower jejunum. Celiac angiography demonstrated a hypervascular tumor stain in the branch of the jejunal artery. The serum HCG level was elevated. Gynecological examination revealed nothing abnormal. A small intestinal neoplasm was diagnosed, and a partial resection of the jejunum was performed. Endoscopy on the operating table showed a large, irregularly shaped sessile ulcer. Histologically the tumor was diagnosed as choriocarcinoma, composed of syncytiotrophoblastic cells and cytotrophoblastic cells. Immunohistochemical staining for HCG was positive. No metastasis was present. Although extragenital choriocarcinoma in the small intestine is rare, it should be included in the differential diagnosis of small intestinal neoplasm.

Choriocarcinoma↗

PubMed1991

Staging and follow-up of primary gastric lymphoma by endoscopic ultrasonography.

The usefulness of endoscopic ultrasonography (EUS) was assessed for diagnosing the depth of invasion in the gastric wall, the infiltration to the adjacent organs, and detecting regional lymph node involvement in primary gastric lymphoma. EUS was performed in 11 patients with primary gastric lymphoma who subsequently underwent gastrectomy with lymph node dissection, as well as chemotherapy in some cases. EUS findings showed a good correlation with the histopathology of the resected specimens. An accurate diagnosis of the depth of invasion into the gastric wall was made in 10 of 11 patients using the same T grade of the 1987 TNM system for gastric carcinoma. EUS also clearly visualized the reduction of depth of tumor invasion in two patients who underwent chemotherapy. Perigastric lymph node involvement could be detected accurately in nine of 11 patients. In conclusion, EUS is an excellent and sensitive diagnostic modality for the preoperative staging and follow-up of primary gastric lymphoma.

Aged↗

PubMed1991

Endoscopic ultrasonography in staging a primary early gastric lymphoma: report of a case.

A 74-year-old woman with a history of a benign gastric polyp was admitted to our hospital with a complaint of epigastric discomfort. A diagnosis of primary gastric lymphoma was confirmed by endoscopy and results of abrasive cytology. Endoscopic ultrasonography (EUS), performed prior to surgery, demonstrated clearly the submucosal invasion of the gastric lymphoma. Histopathology on the depth and the involvement of perigastric lymph nodes of surgical specimen confirmed the accuracy of the EUS findings. Thus EUS offers a means of early preoperative diagnosis and staging of gastric lymphoma, and that is superior to conventional endoscopy in such cases.

Aged↗

PubMed1990

Mitomycin C cross-resistance induced by adriamycin in human ovarian cancer cells in vitro.

We prepared Adriamycin-resistant cancer cells by exposing an ovarian serous cystadenocarcinoma cell line to the drug. The resistant cells also showed cross-resistance to a wide variety of other compounds, including vincristine, vinblastine, actinomycin D, daunorubicin, mitomycin C and carboquone. Against vincristine, the cells showed a greater than 5,000-fold increase in resistance, far surpassing their resistance to the selection drug. The resistant cells displayed a decrease in intracellular Adriamycin content and an increase in the mRNA of the mdr-1 gene coding for P-glycoprotein, with no amplification of the DNA. In revertant cells, resistance to Adriamycin was lost, but that to mitomycin C was maintained. Adriamycin resistance was partially overcome by the addition of verapamil or cyclosporin A, but cross-resistance to mitomycin C was not influenced at all. These results strongly suggest that the resistance to mitomycin C observed in our Adriamycin-resistant cells was due to some other mechanism than that causing multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1990

Alpha-fetoprotein in malignant germ cell tumors of the ovary.

To investigate the clinical significance of alpha-Fetoprotein (AFP) in malignant germ cell tumors of the ovary, we studied 46 patients who were treated by the Tokai Ovarian Tumor Study Group. The 46 patients had the following tumors: immature teratoma (IT), 17 cases; endodermal sinus tumor (EST), 16 cases; mixed germ cell tumor containing EST, 11 cases; embryonal carcinoma, 1 case; polyembryoma, 1 case. In all 29 non-IT cases, AFP was positive, and in 27 cases (93%) the level was above 1000 ng/ml. In 11 of 17 cases of IT (64.7%), AFP levels were elevated and in 1 case the level was above 1000 ng/ml. Elevation of the AFP level above 1000 ng/ml suggested the presence of EST. AFP levels were monitored in 27 of 29 cases without IT during treatment and follow-up. It was found that AFP levels should be monitored closely for at least 1 year after induction of remission. No recurrence was observed when AFP continued to be negative longer than 1 year. The mean interval to clinical recurrence from the reelevation of AFP was 4 months (1.4-9 months). An increase in the AFP to a positive level, even without clinical signs of recurrence, should be regarded as a recurrence. AFP was found to be a useful tumor marker for the diagnosis and management of malignant germ cell tumors of the ovary.

Adult↗

PubMed1990

Effects of pretreatment with 2-O-octadecylascorbic acid, a novel free radical scavenger, on reperfusion-induced arrhythmias in isolated perfused rat hearts.

The effects of pretreatment with 2-O-octadecylascorbic acid (CV-3611), a novel liposoluble free radical scavenger, on reperfusion-induced arrhythmias were studied in isolated perfused rat hearts (n = 15 per group). The hearts were subjected to 10 min of coronary artery occlusion and 3 min of reperfusion. Pretreatment with CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular fibrillation (VF; reversible plus sustained) from its control value of 93% to 47% (p less than 0.05). Furthermore, CV-3611 reduced the incidence of sustained VF in a dose-dependent manner, from 67% in the control group to 13% in the CV-3611, 20 mg/kg treated group (p less than 0.01). CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular tachycardia (VT) from its control value of 93% to 73%. Pretreatment with ascorbic acid (5 mg/kg) had no effect on VF and VT. The myocardial content of CV-3611 was proportional to the dosage. We concluded that CV-3611 could reduce significantly the susceptibility to reperfusion-induced arrhythmias, especially VF, and that its effect may be due to the elimination of oxygen-derived free radicals by CV-3611 present in the membrane and the capture of lipid radicals, thereby inhibiting lipid peroxidation.

Animals↗

PubMed1990

Computerized M-mode echocardiographic assessment of left ventricular diastolic function in patients with familial amyloid polyneuropathy.

To determine left ventricular diastolic properties in patients with familial amyloid polyneuropathy, 23 patients were studied by digitized M-mode echocardiography and were compared with 15 age-matched normal subjects. None of the patients had restrictive ventricular physiology and all but two showed normal left ventricular fractional shortening. Both the normalized peak rate of diastolic increase in left ventricular internal dimension and the normalized peak rate of diastolic thinning of posterior wall were significantly lower in patients than in normal subjects (2.0 +/- 0.8 vs 3.0 +/- 0.4 sec-1; p less than 0.001, and 2.5 +/- 1.2 vs 5.8 +/- 1.0 sec-1; p less than 0.001, respectively). The left ventricular isovolumic relaxation time in patients was 91.5 +/- 22.2 msec, compared with 64.0 +/- 2.6 msec in normal subjects (p less than 0.001). Of the 18 patients without clinical evidence of overt heart disease, 12 had normal ventricular wall thickness and normal fractional shortening, but 10 of the 12 exhibited some abnormalities in diastolic properties. In addition, indexes of diastolic function were significantly related to ventricular wall thickness alone. These findings indicate that left ventricular diastolic abnormalities precede the development of clinically overt heart disease, ventricular wall thickening, and systolic dysfunction and may be related to intramyocardial amyloid infiltration with resultant fibrosis in patients with familial amyloid polyneuropathy.

Adult↗

PubMed1990

Metabolic risk factors in the normolipidemic male patients with angiographically defined coronary artery disease.

The relationship of plasma lipid and apolipoprotein (apo) concentrations and plasma insulin response to oral glucose load to angiographically determined coronary artery disease (CAD) was investigated in 65 normolipidemic (plasma cholesterol less than 230 mg/dl and plasma triglyceride less than 150 mg/dl) males. According to the results of coronary angiography, the patients were divided into 2 groups: patients with normal coronary artery, NCA group (n = 21); and patients with coronary artery disease, CAD group (n = 44). No significant differences in concentrations of plasma cholesterol and triglyceride were observed between the CAD and NCA groups. In the CAD group cumulative lifetime tobacco consumption was higher and high density lipoprotein (HDL) cholesterol concentration was lower than those in the NCA group. The variables that correlated with the severity of CAD, defined by the number of lesions and percent stenosis, were levels of plasma apo A-I and apo B. Prevalence of subjects with reduced oral glucose tolerance did not differ between 2 groups. However, hyperinsulinemic response to oral glucose load was present in the CAD group. HDL-cholesterol concentration, the sum of plasma insulin levels and the magnitude of the early insulin response during oral glucose challenge were accurate predictors of the presence of but not the severity of CAD. Multivariate analysis of the data confirmed the independent effect of plasma levels of apo A-I and apo B on the severity of CAD. The present data indicated that plasma levels of apo A-I and apo B were powerful discriminators in the normolipidemic CAD patients and that a high insulin response might be an indicator of enhanced susceptibility to the distinct coronary atherosclerosis.

Adult↗

PubMed1990

[Toxicity of bis (tri-n-butyltin) oxide on learning and development in the rat].

The toxicity of bis (tri-n-butyltin) oxide (TBTO) was studied in THA rats. Doses of 0 (control), 10 or 15 mg/kg/day of TBTO were administered to adult rats for 12 consecutive days, and 0, 5 or 10 mg/kg/day was given to pregnant rats from day 6 to day 20 of gestation by gastric intubation. In the adult rat exposure experiment, the 15 mg/kg group showed slightly decreased body weight and spontaneous motor activity, and a low avoidance rate in the Sidman avoidance test in the early stage of administration. In the pregnant-rat exposure experiment, no effect of TBTO was seen in either the 5 mg/kg or 10 mg/kg groups in dams while all pups in the 10 mg/kg group died by postnatal day 3. Little effect of TBTO on body weight, pinna detachment, incisor eruption, eye opening, surface righting, cliff avoidance, pivoting, negative geotaxis and auditory startle was found in the 5 mg/kg pups. In the Sidman avoidance test, the avoidance rate of the 5 mg/kg pups was lower than that of control pups in the early stage of the session. In a water E-maze test, the swimming time to the goal and the number of errors were increased in the 5 mg/kg pups. In a reversal water E-maze test, increases of the swimming time to the goal and the number of errors made by the 5 mg/kg pups were marked. These results suggest that TBTO administration disrupts the learning acquisition of rats, and that the toxicity of TBTO is greater in prenatally exposed pups than in adult rats.

Animals↗