Search PubMed⌕ Search

Biomedical subjects

K Mimura

Publications and source records attributed to K Mimura.

At least 19 recordsLinked to original sources
PubMed1992

Hydroxyl radical formation by UV-irradiated epidermal cells.

To elucidate the mechanism of sunlight-induced skin damage, guinea pigs were exposed to UV light (280-320 nm, UV B, 4 J/cm2) and a homogenate of the epidermis was examined by means of the thiobarbituric acid (TBA) test. Three hours after the exposure, TBA-malondialdehyde adducts had increased while glutathione reductase activity had decreased, indicating lipid peroxidation. To detect the initial species, spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was applied to a suspension of illuminated epidermal cells (0.5 J/cm2). An ESR signal obtained only with irradiation comprised a 1:2:2:1 quartet [a(N)= a(beta H) = 1.49 mT] attributable to a spin adduct of hydroxyl radicals. These results suggest that sunlight exposure of skin may lead to hydroxyl radical generation and simultaneous lipid peroxidation.

Animals↗
PubMed1992

[Mycoplasma pneumoniae respiratory tract infection prevailing among infants at a nursery school].

Mycoplasma pneumoniae (M. pneumoniae) infection in infants had been considered to be very rare, but recently some clinical cases have been reported. We experienced an epidemic of M. pneumoniae infection in a nursery school, and compared M. pneumoniae infection in infants with that in preschool and school children to investigate the features of infantile M. pneumoniae infection. We obtained the following clinical findings in 15 infantile patients with M. pneumoniae infection: The maximum body temperature scarcely increased to 38.5 degrees C or more and the period of high temperature and cough was shorter in infant patients than in preschool and school aged patients. Stridor occurred in 4 patients but skin disorder was not observed. In the laboratory findings, the white blood cell count tended to increase with no changes in neutrophil/lymphocyte ratio and CRP increased slightly. M. pneumoniae antibody was negative in all the patients except 3 and old hemagglutination tests were positive in only 4 patients. The chest X-ray examinations showed a mild increase in the hilar shadow. However, the sequentially located homogeneous shadow which is commonly seen in preschool and school aged patients was not detected. M. pneumoniae antibody scarcely increased in infantile patients but M. pneumoniae was isolated by throat culture from 14 of the 15 patients who were diagnosed as having M. pneumoniae infection.

Child Day Care Centers↗
PubMed1992

Seroepidemiology status of Nepalese against hemolytic streptococcal infection in Katmandu.

Immune status of apparently healthy Nepalese against hemolytic streptococci was studied by measuring antibodies to various streptococcal antigens such as streptolysin-O (SO), streptokinase (SK), deoxyribonuclease-B (DN-B) and streptococcal polysaccharide (SP). The normal range of anti-streptolysin-O (ASO), anti-streptokinase (ASK), anti-deoxyribonuclease-B (ADN-B) and anti-Streptococcus polysaccharide (ASP) was 60-480 (T.U.), 40-1024 (titer), 60-1280 (titer) and less than 2-128 (Unit), respectively. No difference was observed between the two sexes. ASO and ADN-B were measured by the neutralization method. Passive hemagglutination (PHA) was used to measure ASK and ASP. These values were 2-3 fold higher than those obtained on the Japanese subjects.

Adolescent↗
PubMed1992

Effect of glucose on Na, K-ATPase activity in cultured bovine aortic endothelial cells.

The effect of high concentrations of glucose on Na, K-ATPase activity and the polyol pathway was studied using cultured bovine aortic endothelial cells. Na, K-ATPase activity was expressed as ouabain-sensitive K+ uptake. A significant decrease in Na, K-ATPase activity with an intracellular accumulation of sorbitol was found in confluent endothelial cells incubated with 400 mg/dl glucose for 96 h. However, there was no significant change in the Na, K-ATPase activity or sorbitol content of the cells incubated with 100 mg/dl glucose plus 300 mg/dl mannitol. The decrease in Na, K-ATPase induced by the high glucose concentration was restored by the simultaneous addition of 10(-4) M ponalrestat (ICI 128,436; Statil), an aldose reductase inhibitor. The addition of this agent also significantly reduced the increase in sorbitol induced by high glucose levels. These results suggest that the decrease in Na, K-ATPase activity induced in cultured aortic endothelial cells by high concentrations of glucose may be caused in part by the accumulation of sorbitol.

Aldehyde Reductase↗
PubMed1992

Effect of pravastatin on serum lipids, apolipoproteins and lipoprotein (a) in patients with non-insulin dependent diabetes mellitus.

In 43 patients with non-insulin dependent diabetes mellitus (NIDDM) associated with hypercholesterolemia, the effect of pravastatin, a potent HMG CoA-reductase inhibitor, on serum lipids, apolipoproteins and lipoprotein (a) was examined. After 1 to 3 months administration of 10 mg per day of pravastatin, the serum levels of total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) were significantly decreased, while the serum level of high density lipoprotein cholesterol (HDL-C) was significantly increased in patients with NIDDM. The levels of apolipoproteins B (apo B) and E were significantly decreased, while apolipoprotein AI (apo A-I) was not changed by the administration of pravastatin. The atherogenic indices (LDL-C/HDL-C and apo B/apo A-I) were significantly decreased by the administration of this drug. The serum lipoprotein (a), which was increased in the diabetic patients, was not affected by the pravastatin treatment. Plasma glucose and hemoglobin A1c levels were not affected by the treatment. We concluded that pravastatin is a potentially useful agent in the treatment of hypercholesterolemia in patients with NIDDM.

Apolipoproteins↗
PubMed1992

Effects of brief physical exercise on the concentrations of immunoreactive superoxide dismutase isoenzymes in human plasma.

Effects of cycle ergometer exercise (approximately 75% VO2max for 15 min) on the concentrations of immunoreactive Mn- and CuZn-superoxide dismutases (SOD) in plasma were studied on 10 male students. During the experimental period, Mn-SOD concentration did not vary substantially. On the other hand, CuZn-SOD concentration decreased markedly at 15 min and 24 hr after the exercise; that is, CuZn-SOD appeared to differ virtually from Mn-SOD in recovery pattern.

Adult↗
PubMed1992

Prevention of aortic calcification in patients on hemodialysis by long-term administration of vitamin E.

The effects of vitamin E on the progress of atherosclerosis in patients on hemodialysis was investigated clinically using ACI. There was a significant suppression of the increase in ACI in group A, compared to group B, at the time of observation in each year. On the other hand, no significant changes were noted in BWD, CTR, BP and blood chemical examination, except that the level of MDA was significantly decreased in group A as compared with that in group B 4 years later. Since ACI is an index representing atherosclerosis, the results of this study seemed to suggest that the progress of atherosclerosis was suppressed by long-term administration of vitamin E in patients on hemodialysis.

Aortic Diseases↗
PubMed1992

[Complex formation of ulinastatin with alpha-thrombin].

The inhibition mode of ulinastatin was indicated noncompetitive by the Lineweaver-Burk's double reciprocal plotting method using the production rate of fibrinopeptide A. Consequently Km of alpha-thrombin could be calculated 2.8 mM and its Vmax was reduced from 24 U/l to 15 U/l by the addition of ulinastatin and Ki of ulinastatin was 1.05 x 10(-2) M. The complex of ulinastatin and alpha-thrombin were found. Furthermore, the mixing of alpha-thrombin, AT-III and ulinastatin produced a larger complex on SDS-PAGE at pH 7.0, and it was evident by the use of Western blotting method, that the complex was consisted of alpha-thrombin, AT-III and ulinastatin. Although ulinastatin and thrombomodulin showed multiple similarities in inhibitory functions on alpha-thrombin, still there are some differences functioning on alpha-thrombin, because of the different binding sites of ulinastatin and thrombomodulin on alpha-thrombin, indicating no crossreaction for antithrombomodulin monoclonal antibody relating to alpha-thrombin binding site of thrombomodulin and it could be contributed to form noncompetitive or uncompetitive inhibitors.

Binding Sites↗
PubMed1992

Alterations in femoral bone histomorphometry and vitamin D metabolism in neonatal streptozotocin-induced diabetic rat.

Histomorphometric examination and histological observation of femoral bone were performed on long-standing neonatal streptozotocin-induced diabetic rats (n2STZ, n5STZ) as a human model of non-insulin-dependent diabetes mellitus. The growth and strength of femurs decreased in the STZ diabetic rats. Histomorphometric parameters such as cortical bone thickness, number of metaphysical trabeculae and percent trabecular volume of metaphysical area all significantly decreased in the STZ diabetic rats. There were no significant differences in parameters between the n2STZ and n5STZ diabetic rats. Histological findings demonstrated no significant change in the number of osteoclasts in femur nor change corresponding to osteomalacia. Bone absorption in the STZ diabetic rats appeared unchanged. The plasma calcium level did not change in the STZ diabetic rats, although their plasma phosphate or A1-p levels increased. Circulating 24, 25 (OH)2D3 was significantly lower in the STZ diabetic rats than the controls. However, 25 (OH) D3 or biologically active 1, 25 (OH)2D3 was not different between the controls and STZ diabetic rats. Osteopenia is thus present in the femurs of long-standing neonatal STZ diabetic rats, due in part to abnormal vitamin D metabolism.

Animals↗
PubMed1992

Fibrinolysis activity promotes tumor invasiveness of B16 melanoma cell lines through a reconstituted gel matrix.

We studied the role of the fibrinolytic function in the invasiveness of murine melanoma B16F1 and F10 cells using a reconstituted matrix on a filter in a modified Boyden chamber. The main species of plasminogen activators (PAs) synthesized in cell lysates and released into conditioned media by these cells was found to be tissue-type PA (t-PA). The invasiveness of these cell lines was enhanced by adding plasminogen to the gel matrix. This enhancing effect of plasminogen was markedly suppressed by adding anti-t-PA IgG and plasmin inhibitors into the gel matrix, but less affected by anti-urokinase-type PA (u-PA) IgG, offering more evidence to the hypothesis that the activation of the fibrinolytic system by PAs plays an important role in the invasiveness of murine melanoma B16 cell lines, and indicating that t-PA contributed more than u-PA to the invasive potential of these cells into the pericellular matrix.

Animals↗
PubMed1992

Study on the inhibitory effect of uremic plasma on lipoprotein lipase.

An investigation was undertaken to determine which plasma factors from normal controls and patients with chronic renal failure (CRF) exert have inhibitory effects on the activity of lipoprotein lipase (LPL) purified from heparinized human plasma by using an accurate LPL assay system. Inhibitors of LPL were found to be present in the plasma. The inhibition of the LPL activity was significantly greater in CRF patients than in normal controls. Following hemodialysis (HD), the same concentration of uremic plasma led to less inhibition. The inhibitors existed only in lipoprotein deficient plasma (LPDS), which demonstrated an LPL-inhibitory activity at extremely high concentrations with a significant difference between the patients and normal controls. There was no difference between the two groups at low concentrations. A specific inhibitory effect on LPL in LPDS was noted in the 7S and 4S fractions separated by gel filtration employing Sephacryl S-200 column chromatography. The inhibitory effect of the 7S fraction was found to be dependent on the concentration, and the difference between the two groups was similar to that for LPDS. The results obtained in the present study suggest that the plasma from CRF patients exhibited a strong inhibitory action on the LPL activity as compared to the plasma from normal controls, and the inhibitory action was due primarily due to poor excretion of dialyzable inhibitors.

Adult↗
PubMed1992

[Inhibitory effect of ulinastatin on the alpha-thrombin activation of factors V and VIII].

Ulinastatin is a remedy of urine serinprotease inhibitors and also it inhibits enzymatic activities of several blood coagulation factors. The action of ulinastatin on alpha-thrombin shows noncompetitive inhibition with the formation of enzyme-inhibitor complex. In this study, the effects of ulinastatin on the alpha-thrombin activation of factors V and VIII are observed by 5-20% gradient gel SDS PAGE with or without Western blotting method. The addition of ulinastatin to the mixture of factor V and alpha-thrombin inhibits the production of active peptides proceeded in the alpha-thrombin activation process of factor V. Furthermore, using anti-factor VIII 43KDa peptide monoclonal antibody with Western blotting method, the addition of ulinastatin to the mixture of alpha-thrombin and factor VIII indicates to inhibit the release of 43KDa peptide from factor VIII in the process of factor VIII activation induced by alpha-thrombin.

Factor V↗
PubMed1991

Cortical modulation of visual contrast.

The mechanisms that produce simultaneous contrast have been thought to depend on retinal gain control and the retina is supposed to send signals to the brain only in terms of local-border contrast (Shapley, 1986). However, it was found that, when an object on a uniform background and border-concealing stimuli are presented to different eyes, the brightness of the object is greatly influenced if the border-concealing stimuli are perceptually superimposed on the border of the object. The change in the object's brightness in this condition is almost identical to that observed when both the object and the border-concealing stimuli are presented to the same eye, suggesting that the brain can compute brightness by using luminosity information when contrast information is disrupted.

Adult↗
PubMed1991

Effect of platelet-activating factor on lipoprotein lipase and blood lipids.

We investigated the effect of platelet-activating factor (PAF) and of the PAF specific antagonist CV-6209 on plasma lipid metabolism, and particularly on post-heparin plasma lipolytic activity in male Wistar rats. Lipoprotein lipase (LPL) activity was enhanced by intravenous injection of PAF before intravenous injection of heparin when the PAF dose was low (0.2 micrograms/kg). PAF activated hepatic triacylglycerol lipase (HTGL) activity dose-dependently. Plasma triacylglycerols (TG) significantly decreased with the activation of LPL and/or HTGL. Plasma total cholesterol (TC) and phospholipid (PL) levels decreased at a low dose of PAF (0.2 micrograms/kg), but increased when higher doses were used. The PAF antagonist CV-6209 partially reversed the PAF induced effects on HTGL, TC and PL.

Animals↗
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↗