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Biomedical subjects

K Mimura

Publications and source records attributed to K Mimura.

At least 37 records · Page 2Linked to original sources
PubMed1991

Intercellular communication in cultured rabbit gastric epithelial cells.

The effects of drugs related to cyclic AMP and a tumor promoter, phorbol ester, on intercellular communications via gap junctions were investigated by the Lucifer Yellow-transfer method in cultured rabbit gastric epithelial cells. Cells were in contact with each drug for 4 hr before the microinjection of the dye into a cell. Dye transfer capacity was significantly increased by dibutyryl cyclic AMP (10(-3) M), theophylline (10(-3) M), 3-isobutyl-1-methylxanthine (10(-4) M), forskolin (10(-6) M) and irsogladine (10(-4) M); and it was inhibited by 12-O-tetradecanoyl-phorbol-13-acetate (100 ng/ml). These results suggest that the intercellular communication between cultured rabbit gastric epithelial cells is upregulated by cyclic AMP.

Animals↗
PubMed1991

The autotransfusion effect of external leg counterpressure in simulated mild hypovolemia.

We examined the cardiovascular response of external leg counterpressure in healthy volunteers at 100 mm Hg compression pressure. To stimulate mild hypovolemia, measurements were made with the subjects in a 60 degrees head-up tilt position. Left ventricular end-diastolic volume (LVEDV) and cardiac output (CO) were calculated from two-dimensional echocardiography. Flow through the inferior vena cava (IVC) below the origin of the hepatic veins was determined by the Doppler ultrasound technique. The application of counterpressure significantly increased LVEDV, CO, and arterial blood pressure over that seen with tilting without the device. These responses were accompanied by a small but significant increase in IVC flow. We therefore concluded that external leg counterpressure transferred blood to the central circulation by compression of the venous capacitance vessels (an autotransfusion effect) in mild hypovolemia, but such an effect may not benefit patients in a hypovolemic shock state because of the small amount of translocated blood.

Adult↗
PubMed1990

Developmental process of visual pattern discrimination in the fly.

It has been found that the development of visual pattern discrimination in the fly is strongly influenced by visual experience in the early stage of post-emergence. Behavioral experiments were performed to determine the details of the temporal conditions of the visual experience and to obtain a lead to the determination of the molecular mechanism underlying the developmental process. By anesthetizing the flies with chilling at various periods post-emergence, it was demonstrated that visual experience during 5 h post-emergence must be followed by normal neuronal activity within a very short time of 15 min for the normal development of visual pattern discrimination to occur. The subsequent development of normal pattern discrimination required the maintenance of normal neuronal activity for at least 5 h. Injection of some protein synthesis inhibitors to the fly head before or immediately after visual experience resulted in impairment of the development of visual pattern discrimination, thus supporting the developmental process revealed by the chilling experiment. Moreover, both the chilling experiment and injection of inhibitors of protein synthesis showed that the neuronal mechanisms were different for phototaxis and for pattern discrimination, suggesting that the former is a natural function while the latter is an acquired function after emergence.

Aging↗
PubMed1990

Corticotropin-releasing hormone- and adrenocorticotropin-producing pituitary carcinoma with metastases to the liver and lung in a patient with Cushing's disease.

A 53-yr-old man with Cushing's disease was found to have a pituitary carcinoma with metastases to the liver and lung which produced both CRH and ACTH simultaneously. Despite removal of the pituitary tumor, his Cushing's disease worsened. Endocrinological examination then demonstrated elevated plasma CRH and markedly elevated plasma ACTH, beta-lipotropin, and cortisol concentrations, increased urinary 17-hydroxycorticosteroid and 17-ketosteroid excretion, and no suppression of serum cortisol after low or high dose dexamethasone administration. Urinary 17-hydroxycorticosteroid excretion increased in response to metyrapone, and lysine vasopressin elicited a striking increase in plasma ACTH. A computed tomographic scan of abdomen revealed multiple hypodense areas in the liver and bilateral adrenal hyperplasia. Postmortem histological examination revealed a necrotic hemorrhagic pituitary carcinoma with metastases to the liver, lung, and olfactory bulb. Immunohistochemical staining, gel filtration, and Northern blot analysis of liver and lung metastases revealed evidence of the production of both CRH and ACTH in these metastases. We concluded that the patient's pituitary carcinoma produced both CRH and ACTH.

Adrenocorticotropic Hormone↗
PubMed1990

[Discriminant function analysis for evaluating the status of coronary heart disease risk].

We investigated to discriminate those individuals categorized by 1. obesity, 2. hypercholesterolemia, 3. hypertension, 4. low maximal oxygen uptake, 5. an abnormal electrocardiogram reflecting ischemic patterns, and/or 6. real sedentary life, from relatively healthier individuals without coronary heart disease (CHD) risk factors. One hundred and six Japanese women, aged 30 to 72 years, all of whom were in the postabsorptive state, were recruited in a series of tests for anthropometric and physiologic profiles both during the resting state and during the submaximal-maximal cycling exercise. Subjects were categorized into two groups--those who possessed four or more of the above 1, 2, 3, 4, 5, and 6 (high-CHD-risk group, n = 15) and apparently healthy individuals with a minimum number of risk factors (low-CHD-risk group, n = 83). Analyses of the data revealed that a combination of 8 variables extracted from among original 25 variables accurately classified 13/15 (87%) of high-CHD-risk group and 77/83 (93%) of low-CHD-risk group (mean = 90/98 or 92%) into their respective groups. The 8 variables were double product, Katsura index, waist girth, chest girth, TG, TC, and skinfold thicknesses at the subscapular and abdominal sites. Subsequent t-test identified significant differences between groups not only for VO2max, SBP and TC but also for DBP, LDLC, TG, Hb, HR, and HRmax. Most of these differences were of a much greater magnitude compared to the existing difference in chronological age. These findings suggest the usefulness and importance of anthropometric and blood lipid variables in the explanation of differences in the health status between high-CHD-risk women and their counterparts.

Adult↗
PubMed1990

Proximal gastric vagotomy with carbon dioxide laser: experimental studies in animals.

Proximal gastric vagotomy has been widely used as a surgical treatment for peptic ulcer disease. However, it is technically complex and time-consuming. Moreover, it may cause circulatory problems in the gastric mucosa. We have reported a new method of blood flow-preserving vagotomy with a carbon dioxide laser (CO2 laser vagotomy) developed in our laboratory. To assess its efficacy, we used cysteamine-induced ulcer and measured gastric mucosal blood flow in rats. The incidence of cysteamine-induced ulcer formation was reduced significantly in the group that underwent CO2 laser vagotomy compared with a group treated with proximal gastric vagotomy. Gastric mucosal blood flow was significantly better in the CO2 laser vagotomy group. Long-term follow-up of acid reduction was evaluated in dogs by the pentagastrin-stimulation test. Acid reduction in dogs was satisfactory during the 12 months of this study. CO2 laser vagotomy is a new, easy, time-saving, and circulatory-preserving technique for peptic ulcer disease.

Animals↗
PubMed1989

Minimum enzyme unit for Na+/K+-ATPase is the alpha beta-protomer. Determination by low-angle laser light scattering photometry coupled with high-performance gel chromatography for substantially simultaneous measurement of ATPase activity and molecular weight.

The oligomeric state of canine renal NA+/K+ -ATPase solubilized by octaethylene glycol n-dodecyl ether (C12E8) was studied by means of low-angle laser light scattering photometry coupled with high-performance gel chromatography (HPGC). At around 0 degree C the solubilized enzyme was separated into the (alpha beta)2-diprotomeric and alpha beta-protomeric protein components with Mr values of 302,000 +/- 10,000 and 156,000 +/- 4,000, respectively, in approximately equal quantities. As the temperature of chromatography was increased toward 20 degrees C, the two protein components converged into a single major component. The Mr of this component depended on the monovalent cation included in the elution buffer, and was 255,000 or 300,000 in the presence of 0.1 M NaCl or 0.1 M KCl, respectively. A computer simulation technique showed that the solubilized enzyme was in a dissociation-association equilibrium of 2 protomers = diprotomer at 20 degrees C, and the difference in apparent Mr of the solubilized enzyme between the two species of monovalent cation was interpreted by an association constant (Ka) in the presence of 0.1 M KCl that was about 50-fold larger than in the presence of 0.1 M NaCl. In order to measure ATPase activity and Mr of the solubilized enzyme simultaneously, a TSKgel G3000SW column had been equilibrated and was eluted with an elution buffer containing 0.30 mg/ml C12E8 and 60 microgram/ml phosphatidylserine (bovine brain) as well as the ligands necessary for the enzyme to exhibit the activity at pH 7.0 and 20 degrees C. The solubilized enzyme was always eluted as a single protein component irrespective of the the amount of the protein applied to the column, ranging between 240 and 10 microgram. The Mr of the protein component, however, decreased from 214,000 and 158,000 with the decrease of the protein amount. The specific ATPase activity, however, remained constant at a level of 64 +/- 4% of that of the membrane-bound enzyme even in the range of protein concentration sufficiently low as to allow the enzyme to exist only in the protomeric form. Thus, the alpha beta-protomer is concluded to be the minimum functional unit for the ATPase activity. The value of Ka obtained from the concentration-dependent dissociation curve was 5 . 10(5) M-1 for the enzyme turning over, and 1.1 . 10(7) M-1 for the enzyme inhibited with ouabain. It was discussed, based on the values of Ka obtained, that the enzyme would exist as the diprotomer or the higher oligomer in the membrane.

Animals↗
PubMed1989

Aneurysm in the sequestrated lung and aortitis associated with the malignant rheumatoid arthritis.

A scar phase of rheumatoid aortitis and aneurysms in the sequestrated lung with a lesion continuous to an aortic lesion was found in autopsy specimens from a 50 year-old-woman, who had suffered from generally disseminated carcinoma of the breast. The aorta revealed a scar phase of granulomatous panaortitis continuously from the ascending to the descending thoracic aorta. The media and adventitia of the aorta were largely replaced by scar tissue, although the aortic valve was spared. The systemic arteries in the sequestrated lung were destroyed completely by the necrotizing angiitis and showed saccular aneurysm filled with organizing fibrin thrombus. The pulmonary artery was intact. These findings suggest that the saccular aneurysm in the sequestrated lung was produced by necrotizing angiitis, in association with rheumatoid aortitis.

Aneurysm↗
PubMed1989

Activation of proteases in cerulein-induced pancreatitis.

The activation of zymogen proteases and lysosomal enzyme cathepsin B in the pancreas was investigated in cerulein-induced pancreatitis in rats. Acute pancreatitis was induced by two intraperitoneal injections of 40 micrograms/kg of body weight of cerulein at intervals of 1 h. After the first cerulein injection, the active trypsin and elastase contents in the pancreas tissues significantly increased, and reached the highest level at 3 h after the first injection, followed by peaks at 5 h in the serum amylase and lipase levels and the pancreas wet weight. Cathepsin B contents in pancreas tissues showed a parallel increase with active zymogen enzymes during the first 3 h of pancreatitis. These findings may suggest that the intracellular activation of trypsinogen is an important step in the development of cerulein-induced acute pancreatitis and that cathepsin B plays a role in the activation of trypsinogen in pancreatic acinar cells.

Amylases↗
PubMed1989

Heart rate response to treadmill exercise in children of ages 4-6 years.

In order to investigate some characteristics of physical fitness in children, we measured the heart rate of 1069 kindergarten children (aged 4-6 years) and 20 adults during treadmill running. After analyzing the data we obtained the following results: heart rate before, during, and after the running tended to diminish with the increase in age of the subjects in both men/boys and women/girls. The relationship of the heart rates before running and the maximum heart rates during in 25 m run, standing long jump, and softball throw, showed a significant level of 5-0.1% in both boys/men and girls/women. The heart rates of children before, during and after running were higher than those of adults. The rate of increase in heart rate was higher in adults, while more rapid recovery of heart rate was observed in children, when compared to adults.

Adult↗
PubMed1989

Prerequisites in distance running performance of female runners.

We investigated which attribute or what combination of attributes would best account for distance running performance of female runners. The subjects were 30 well-trained female distance runners, aged 19 to 23 years. Anthropometric and body composition characteristics, pulmonary function characteristics, blood properties, and cardiorespiratory function characteristics were measured at rest or during submaximal and maximal exercise. Analyses of the data showed that the relationship of oxygen uptake corresponding to lactate threshold (VO2T, ml.kg-1.min-1) with each distance running performance was substantially higher as compared with the relationship of other independent variables including maximal oxygen uptake (VO2max). Furthermore, multiple regression analysis indicated that running performances in 3,000m, 5,000m, and 10,000m are best accounted for by a combination of VO2/LT (X1), fat-free weight (X2), and/or mean corpuscular volume (X3). A multiple regression equation for predicting the 5,000m (Y, s) running performance was formulated as Y = -14.75X1-3. 03X2-5.79X3 + 2282.1. We suggest that VO2max would not stand alone as a decisive factor of distance running success in female runners, and that the distance running performance could be better accounted for by a combination of several attributes relating to lactate threshold, body composition, and/or hematological status. The linear regression of the predicted running performance on the actually measured running performance can be accepted in the range of 986-1197s.

Adult↗
PubMed1988

Cytochrome oxidase histochemistry in the effect of light deprivation on the fly visual system.

Deprivation of visual experience for a short time during the early period postemergence in the fly influences strongly the development of visual pattern discrimination. Cytochrome oxidase histochemistry was used to examine the effect of visual deprivation on the development of the neuronal network in the optic lobe. Flies in which one compound eye was covered immediately after emergence were raised under normal light and dark conditions (LD). Other flies were raised without covering of the compound eyes under LD or continuous darkness (DD) as controls. At various periods of postemergence flies from the 3 groups were used for histochemistry. The results indicated that the deprivation caused by unilateral eye covering produced a decrease in cytochrome oxidase staining of the covered side of the retina and optic lobe, but not in the central part of the brain. This asymmetry in staining was not seen in flies of 1-5 days postemergence but became evident after the sixth day postemergence. When flies were raised in DD until the 5th day postemergence and then in LD, the development of asymmetry in cytochrome oxidase staining was delayed. These results confirm previous behavioral experiments on visual deprivation. Both suggest that visual deprivation during the early period of postemergence leads to a long-lasting decrease in neuronal activity.

Animals↗