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Biomedical subjects

K Nishiguchi

Publications and source records attributed to K Nishiguchi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of transfection with a superoxide dismutase expression plasmid on xanthine/xanthine oxidase-induced cytotoxicity in cultured rat lung cells.

We inserted human Cu, Zn-superoxide dismutase (hSOD) cDNA into the eukaryotic expression plasmid (pRc/CMV) under the control of the cytomegalovirus promoter. The hSOD expression plasmid (pRc/CMV-SOD) was transfected in L2 cells by mean of lipofection. The intracellular SOD activity in pRc/CMV-SOD transfected cells (CMV-SOD cells) was about twice that in host cells. However the level of extracellular SOD activity was similar in CMV-SOD and host cells. When exposed to xanthine (X)/xanthine oxidase (XO) to generate active oxygen species, significantly more CMV-SOD cells than host cells survived. The production of lipid peroxidation in host cells significantly increased in the presence of X/XO, but that in CMV-SOD cells did not change. Thus, transfection with SOD gene effectively prevented X/XO-induced cytotoxicity. The results indicated that increasing the level of intracellular SOD activity protected cells against extracellular superoxide anion stress.

Animals↗
PubMed1996

Effect of transfection with superoxide dismutase expression plasmid on superoxide anion induced cytotoxicity in cultured rat lung cells.

Human Cu, Zn-superoxide dismutase (hSOD) cDNA was inserted into a eukaryotic expression plasmid (pRc/CMV) under the control of a cytomegalovirus promoter. The hSOD expression plasmid (pRc/CMV-SOD) was transfected into L2 cells by means of lipofection. The integration of the hSOD gene in genomic DNAs in the cells transfected with pRc/CMV-SOD plasmid was examined by Southern blotting using hSOD cDNA as the probe. However, Southern blots of host cells (without transfection) and CMV cells (pRc/CMV plasmid transfection) indicated no hybridization of hSOD cDNA. Western blots indicated that hSOD was expressed in CMV-SOD cells. The SOD activity in CMV-SOD cells was about twice that in host and CMV cells. Furthermore, this SOD activity in CMV-SOD cells was enhanced for 60 d after the selection of cell clones. After exposure to paraquat and catalase, about 90% of the CMV-SOD cells survived compared with the untreated controls, whereas about 60% of the host cells survived. The production of lipid peroxidation in host cells increased significantly after exposure to both paraquat and catalase, whereas that in CMV-SOD cells did not change. The correlation between the surviving cells and lipid peroxidation was inverse. These results indicated that transfection with the SOD gene was effective against superoxide anion induced cytotoxicity.

Animals↗
PubMed1994

Effect of epidermal growth factor on Cu, Zn-superoxide dismutase expression in cultured fibroblasts from rat skin.

The effects of epidermal growth factor (EGF) on Cu, Zn-superoxide dismutase (SOD) in cultured fibroblasts from rat skin exposed to superoxide anions were studied. Cross-linking of [125I]hEGF using disuccinimidyl suberate and immunoblot analysis using anti-EGF receptor antibody to crude plasma membrane fractions of fibroblasts showed that a 170 kDa EGF receptor protein was present on the membrane, as in A431 cells which over express a specific EGF receptor. The cytosolic SOD enzyme activity in fibroblasts exposed to superoxide anions 24 h after treatment with EGF plus nafamostat (NM), a potent protease inhibitor, was increased 1.6-fold compared to control-treated cells. Treatment with either EGF or NM alone, evoked little increase in SOD enzyme activity. The increase in Cu, Zn-SOD protein levels corresponded to the increase in cytosolic SOD enzyme activity in fibroblasts. The Cu, Zn-SOD mRNA level in fibroblasts treated with EGF plus NM at 3 and 6 h was higher than that of the control. Additionally, levels of [125I]hEGF degradation products released into the medium from fibroblasts exposed to superoxide anions were significantly reduced in the presence of NM. These results suggest that the stabilization of EGF by NM in culture is an important factor in the expression of its effects, and that EGF induces Cu, Zn-SOD expression by accelerating transcription of the Cu, Zn-SOD gene in cells, resulting in their protection from the effects of superoxide anion radicals.

Animals↗
PubMed1993

Cytoprotective effects of epidermal growth factor (EGF) ointment containing nafamostat, a protease inhibitor, on tissue damage at burn sites in rats.

When epidermal growth factor (EGF) ointment containing a protease inhibitor, nafamostat (NM), was applied to burn sites in rats, the superoxide dismutase (SOD) enzyme activity and protein content increased 45% and 60%, respectively, at these sites 1 d after the burns compared with the control ointment. Following treatment with EGF plus NM (EGF + NM) ointment, messenger RNA for SOD also increased, to about 1.6 times that of the control at 1 d after the burn, indicating that this ointment stimulates SOD synthesis at burn sites in vivo. In contrast, following treatment with EGF + NM ointment, the content of heat shock protein (HSP 70) in the burned tissue decreased to about 70% of the control value 1 d after the burn. These findings suggest that EGF + NM ointment alleviated tissue damage at burn sites at an early stage, and that this was related to the stimulation of SOD synthesis and reduced HSP 70 levels. We also examined the effects of SOD ointment on wound healing at burn sites. A dose-dependent increase in the dry weight of granulation tissue at wound sites 3 d after the burn was observed following the application of this ointment. These results suggest that SOD may play an important role in wound healing after burns.

Animals↗
PubMed1992

Intralobular localization of different cytochrome P-450 form dependent monooxygenase activities in the liver of normal and inducer-treated rats.

1. Isolated periportal (PP) and perivenous (PV) hepatocytes from normal and inducer-treated rat livers were used to examine the following: intralobular localization of cytochrome P-450IA, P-450IIB, P-450IIE and P-450IIIA dependent monooxygenase activities and effects of phenobarbital (PB), beta-naphthoflavone (BNF) and pregnenolone-16 alpha-carbonitrile (PCN) on the zonal induction of these monooxygenases. 2. 7-Ethoxyresorufin O-deethylase (7EROD), 7-pentoxyresorufin O-dealkylase (7PROD) and N-nitrosodimethylamine N-demethylase (NAND) activities of PP hepatocytes were not significantly different from those of PV hepatocytes. 3. Ethylmorphine N-demethylase (EMND) activity was significantly higher in PV hepatocytes than in PP hepatocytes of normal rats. 4. EMND activity was induced by PCN and PB treatments. The response of EMND activity to PCN treatment was higher in PP hepatocytes than that in PV hepatocytes, and as a result the PV dominance disappeared following PCN treatment. 5. Extents of the response of this activity to PB treatment were similar in PP and PV hepatocytes, and PV dominance remained unchanged even after induction.

Animals↗
PubMed1992

Pharmacokinetics of zonisamide; saturable distribution into human and rat erythrocytes and into rat brain.

The distribution of zonisamide, a new antiepileptic drug, in erythrocytes and in brain was studied to clarify the factors influencing its distribution in epileptic patients. In both humans and rats, zonisamide was concentrated significantly in erythrocytes in a saturable manner. When the effective concentration of zonisamide in serum was compared with that in blood in nine refractory epileptic patients taking zonisamide chronically, the variation in effective serum concentration was significantly larger than that in blood concentration. In rats, the distribution in the brain also showed saturability. These results suggest that differences in saturable binding to various tissues may contribute to the wide variation that occurs in the effective serum concentration of zonisamide in epileptic patients and that monitoring of the blood concentration of zonisamide may provide useful information for treatment with this drug.

Administration, Oral↗
PubMed1992

[Comparison of bidirectional collagenase perfusion with one way perfusion in the isolation of periportal or perivenous hepatocytes in rats].

To selectively isolate hepatocytes from the periportal (PP) and perivenous (PV) regions of rat liver acinus, we compared two different perfusion methods with collagenase: the bidirectional perfusion method (2-P) and the one way perfusion method (1-P). We determined the optimal conditions for each method on the basis of the zonal selectivity of isolated hepatocytes with a hematoxylin-eosin stained liver specimen. By both methods, hepatocytes were selectively isolated from the PP and PV regions. Comparing cell yield and cell viability after the two perfusion methods, 1-P was found to be better than 2-P. Density gradient centrifugation with Percoll was found to be an effective procedure for removing the damaged hepatocytes. We concluded that 1-P could isolate viable PP and PV hepatocytes with a normal glucagon-cyclic AMP response and ultrafine structure in high yield from rat liver.

Animals↗
PubMed1991

Phytogrowth-inhibitory and antimicrobial activities of 3,4'-dihydroxy-alpha,beta-diethylstilbene, the isomer of diethylstilbestrol.

3,4'-Dihydroxy-alpha,beta-diethylstilbene (I), like diethylstilbestrol (II), showed phytogrowth-inhibitory and antimicrobial activities. First, compound I showed strong growth-inhibitory activity against the roots of two kinds of plants. The inhibitory activity of I was almost equal to that of sodium 2,4-dichlorophenoxyacetate used as a positive control. The phytogrowth-inhibitory activity of I was much higher than that of II. Next, unlike II, I had broad antifungal spectrum against phathogenic fungi. Compound I showed antifungal activity against six kinds of Fusarium oxysporum sp. This compound also had antibacterial activity against pathogenic and plant-pathogenic bacteria. These antibacterial activities of I were as high as those of II, the isomer of I. It should be emphasized that by shifting one of the phenolic hydroxyl groups of II to meta-position, phytogrowth-inhibitory activity was largely increased, while antimicrobial activity was unchanged.

Anti-Bacterial Agents↗
PubMed1990

Differential localization of microsomal mixed function oxidase activity in periportal and perivenous hepatocytes isolated from rat liver.

1. The activity per mg of microsomal protein of aminopyrine N-demethylase was higher in perivenous (PV) than in periportal (PP) hepatocytes of rat, but when it was expressed per cytochrome P-450 content the difference in the activity was not significant. 2. The activity of 7-ethoxycoumarin O-deethylase, when expressed per mg protein and per P-450 content, was significantly higher in PV than in PP cells. 3. The activities of dimethylnitrosamine(DMNA) N-demethylase and aniline p-hydroxylase were not significantly different between two subpopulations of isolated hepatocytes when either expressed per mg protein or per P-450 content.

Aminopyrine↗
PubMed1989

[A case report of tricuspid valve endocarditis due to Staphylococcus aureus with successful surgical treatment].

A 14-year-old boy had previously received right temporal lobectomy under the diagnosis of a malignant brain tumor. About one month after lobectomy, ventriculo-peritoneum shunt and ventriculo-atrium shunt were placed because hydrocephalus was progressed. The patient subsequently had a high fever probably due to wound infection of the shunt operation. Several blood cultures demonstrated Methicillin Resistant Staphylococcus Aureus (MRSA). Several sensitive antibiotics were administered for about 30 days, however these drugs were not effective. According to echocardiography, moderate tricuspid regurgitation and a large vegetation at the tricuspid valve were detected and isolated tricuspid valve endocarditis was diagnosed. Surgical intervention was necessary because of recurrent pulmonary emboli. After tricuspid valve replacement with a Björk-Shiley mechanical valve (31 mm), fever subsided and the patient was discharged on the 38th postoperative day. It is concluded that the surgical indications of the tricuspid valve endocarditis are as follows: 1. recurrent pulmonary emboli, 2. refractory right heart failure, 3. resistance against antibiotics.

Adolescent↗
PubMed1988

Intralobular distribution of rat liver aldehyde dehydrogenase and alcohol dehydrogenase.

1. The activity of liver microsomal high Km-ALDH and mitochondrial low Km-ALDH, which may be primarily responsible for the oxidation of acetaldehyde after ethanol administration was found to be predominantly distributed in the centrilobular area. 2. The activities of other ALDH isozymes in mitochondrial and soluble fractions were evenly distributed in periportal and perivenous regions. 3. The activity of ADH which is involved in production of acetaldehyde was predominantly located in the periportal area. 4. From these results it seems unlikely that a concentration of acetaldehyde after ethanol ingestion is higher in perivenous hepatocytes than in periportal ones. Additional data would be needed to understand fully the mechanism by which ethanol induces predominantly centrilobular liver injury.

Acetaldehyde↗
PubMed1986

Circadian rhythms in the activities of brain and liver aldehyde dehydrogenase isozymes in mice.

Circadian variations in the activities of aldehyde dehydrogenase (ALDH) isozymes in the subcellular fractions of the brain and liver were investigated in male and female mice of C57BL/6J strain. The rhythms in high Km-ALDH activities of brain and liver mitochondrial fractions which existed in ordinary light-dark cycle were not observed in animals maintained in the continuous darkness for two weeks. The rhythms in high Km-ALDH activities of hepatic soluble and microsomal fractions existed in both ordinary cycle and total darkness but the rhythmic phases were different. In the low Km-ALDH activity of hepatic mitochondrial fraction, the circadian rhythm was similar in two lighting conditions. There was sex difference in the existence of the circadian rhythm. It seems that the ALDH activity of mice is influenced by light-dark cycle and sex hormones.

Aldehyde Dehydrogenase↗
PubMed1986

Postoperative left ventricular function in patients with mitral stenosis. The effect of commissurotomy and valve replacement on left ventricular systolic function.

Preoperative and postoperative left ventricular cineangiograms of 26 patients with mitral stenosis (MS) were analyzed to calculate left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and systolic regional wall motion. Nine patients underwent commissurotomy (OMC group) and 17 patients underwent mitral valve replacement (MVR group). In both groups, postoperative EDV, SV and EF tended to increase, while ESV remained unchanged. In the OMC group, systolic wall motion of the left ventricle was found to be improved postoperatively, whereas systolic wall motion in the MVR group was found to be impaired postoperatively. The latter finding was assumed to be due to excision of the papillary muscles and chordae tendineae. Preservation of these structures is likely to be important for better postoperative functional recovery of the left ventricle.

Adult↗