Biomedical subjects

M Kawase

Publications and source records attributed to M Kawase.

At least 19 recordsLinked to original sources

PubMed1997

Attenuation of nitric oxide synthase induction in IRF-1-deficient glial cells.

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. Glial NO production, mediated via induction of iNOS, is thought to facilitate neuronal damage during cerebral ischemia. Recently, interferon regulatory factor-1 (IRF-1) has been reported to be an essential transcription factor for iNOS mRNA induction in murine macrophages. However, expression of IRF-1 and its role in the central nervous system have not been examined. In the present study, by using primary glial cell cultures from mice with targeted disruption of the IRF-1 gene, we investigated whether IRF-1 is involved in iNOS mRNA induction in glial cells. After stimulation with lipopolysaccharide and interferon-gamma, IRF-1 mRNA was strongly induced in wild-type (IRF-1 +/+) glial cells. iNOS mRNA induction and nitrite production in IRF-1 -/- glial cells were reduced as compared with those observed in IRF-1 +/+ glial cells. Diethyldithiocarbamate, a selective inhibitor of nuclear transcription factor kappa B (NF-kappa B), completely inhibited iNOS mRNA induction. These results suggest that not only NF-kappa B but also IRF-1 play important roles in iNOS mRNA induction in the central nervous system.

Animals↗

PubMed1997

Application of glutaraldehyde-crosslinked chitosan as a scaffold for hepatocyte attachment.

The effectiveness of chitosan, a biocompatible polymer derived by the deacetylation of chitin, as a scaffold of hepatocyte attachment, was examined. Since chitosan gel was too fragile to use for cell culture, its free amino groups were crosslinked by glutaraldehyde to increase its strength. Rat hepatocytes seeded onto glutaraldehyde-crosslinked chitosan (GA-chitosan) gel could stably attach to the surface, retaining its spherical form, the same as in vivo, and then release a very small amount of lactate dehydrogenase during the 5 d culture period. By contrast, hepatocytes on a collagen-coated surface spread flat, and they released much more lactate dehydrogenase than those on the GA-chitosan gel. Hepatocytes on GA-chitosan also retained higher urea synthesis activity, a liver-specific function, than those on the collagen-coated surface. These results indicate that chitosan is a promising biopolymer as a scaffold of hepatocyte attachment, which can be applied to an effective bioartificial liver support system.

Animals↗

PubMed1997

Severe hemolysis due to artificial chordae displacement.

Hemolytic anemia is a well-recognized complication of mechanical heart valve prosthesis but, as yet, has not been reported after mitral valve repair with chordal replacement. We report a case of severe hemolytic anemia after mitral valve repair with chordal replacement and Carpentier-Edwards annuloplasty ring insertion. Progressive prolapse of the anterior leaflet due to the artificial chordae being too long caused recurrent regurgitation which was responsible for the hemolysis. The patient also had idiopathic thrombocytopenic purpura, but successful second mitral valve repair was performed after high-dose gamma-globulin therapy.

Anemia, Hemolytic↗

PubMed1997

[Radial artery for coronary artery bypass graft].

Early postoperative results were studied in 50 cases of coronary artery bypass graft (CABG) using a radial artery (RA). The patients ranged in age from 37 to 81 years, with the mean age of 61 years. Of them, 49 were male. An average of RA was 17.6 cm at completion of detachment and 15.6 cm when the graft was cut for use. The internal diameter before anastomosis an average of 3.7 mm on the proximal side and an average of 2.8 mm on the distal side. RA was anastomosed with ascending aorta in 47 cases, with the left internal thoracic artery in 2 cases and with the right internal thoracic artery in one case on the proximal side. RA was anastomosed with the left anterior descending branch area in 6 cases, with the left circumflex branch area in 40 cases and with the right coronary artery area in 4 cases on the distal side. There was no case of operative death, but one patient died while in hospital. The cumulative patency rate of the RA grafts was 95% (n = 40). Early postoperative results of the RA graft were satisfactory, therefore the RA graft were satisfactory, therefore the RA graft was an excellent alternative conduit for myocardial revascularization.

Adult↗

PubMed1996

Inducible nitric oxide synthase following hypoxia in rat cultured glial cells.

Nitric oxide (NO) produced by inducible nitric oxide (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. In the present study, we examined the ability of rat glial cells to produce NO following hypoxia/reoxygenation in vitro by measuring nitrite. The levels of nitrite produced in the cultured media of glial cells significantly increased after 12-h hypoxia but not after 0- and 6-h hypoxia. The NOS inhibitor, NG-monomethyl-L-arginine, decreased hypoxia-induced nitrite formation. In glial cells after hypoxia/reoxygenation, the iNOS and mRNA and protein expressions were detected by reverse-transcription polymerase chain reaction and by immunocytochemical analysis, respectively. The present study provides the first evidence that hypoxia induces NO production from glial cells. This hypoxia-induced, glial cell-derived NO may play a critical role in the pathogenesis of cerebral ischemia in vivo.

Animals↗

PubMed1996

Effects of age on levels of cysteine, glutathione and related enzyme activities in livers of mice and rats and an attempt to replenish hepatic glutathione level of mouse with cysteine derivatives.

There was a large statistically significant decrease in the hepatic level of cysteine and glutathione (GSH) in 24 month-old mice compared to young mice, while, cystine and glutathione disulfide (GSSG) contents in the liver did not differ between young and old mice. Activities of cystathionine gamma-lyase and beta-synthase in mouse liver of the 24 month-old group were significantly decreased. In rats, the hepatic levels of cysteine, cystine, GSH and GSSG exhibited no statistically significant change during aging to 30 month. As the rats matured, total hepatic activities of both cystathionine gamma-lyase and beta-synthase increased with maximum levels at 24 months of age and decreased to the same level found in 5 week old for the former and to 22% of that in 5 week old for the latter. Intraperitoneal administration of diethyl maleate to mice led to depletion of hepatic GSH. When N-acetylcysteine and a thiazolidine derivative were intravenously injected after diethyl maleate administration, the hepatic GSH level of mice was restored to the normal level.

Acetylcysteine↗

PubMed1996

Differential response in the release of hydrogen peroxide between astroglial cells and endothelial cells following hypoxia/reoxygenation.

Hydrogen peroxide (H2O2) and lactate dehydrogenase (LDH) released from cultured astroglial cells (AGs) and brain endothelial cells (BECs) were measured following hypoxia/reoxygenation. AGs released H2O2 to the extracellular space from 8 h of hypoxia with the cellular injury indicated by LDH increase. In contrast, BECs released H2O2 at 4 h of hypoxia, prior to the LDH increase. These results suggest that AGs and BECs play different roles in production and metabolism of oxygen free radicals in the blood-brain barrier (BBB), and AGs may protect the BBB disruption from oxidative stress after hypoxia/reoxygenation.

Animals↗

PubMed1996

Variability and phylogeny of the L1 capsid protein gene of human papillomavirus type 5: contribution of clusters of nonsynonymous mutations and of a 30-nucleotide duplication.

We analyzed the variability and established the phylogeny of the L1 capsid protein gene of 33 isolates of human papillomavirus type 5 (HPV5) obtained from epidermodysplasia verruciformis patients from different continents. By comparing the sequences of a 419-bp fragment with those published for two Japanese isolates, we found 12.9% variable nucleotide positions, defining 25 variants with mutation rates ranging from 0.2 to 8.8%. Such a high intratypic diversity is unusual among HPVs. Nine of the 139 encoded amino acids were variable and 12 protein variants were identified. Fifteen of the 16 substitutions observed were clustered in two short regions. A 9-amino-acid insert, already reported for the Japanese HPV5b isolate, was found within one of the regions in five isolates. Our data support that the insert arose from the duplication of a 30-nucleotide sequence. Phylogenetic trees distributed the DNA variants into three subtypes (a to c) with a divergence higher than 4.5% and allowed the recognition of European and African lineages. By contrast with the trees based on the HPV5 E6 gene, HPV5a DNA variants and the HPV5b variants lacking the insert constituted a single group in the L1 amino acid tree, probably reflecting different levels of structural constraints for the HPV5 L1 and E6 proteins. In that respect, the short variable L1 sequences should represent less constrained regions.

Amino Acid Sequence↗

PubMed1996

Induction of brain-derived neurotrophic factor (BDNF) and the receptor trk B mRNA following middle cerebral artery occlusion in rat.

Middle cerebral artery (MCA) occlusion in halothane-anesthetized rats induced brain-derived neurotrophic factor (BDNF) and the receptor, trk B mRNA, in brain. In situ hybridization studies showed that BDNF and trk B mRNAs were induced in a widespread region of the ipsilateral cortex outside the infarct at 4 h following MCA occlusion. They were also induced in the bilateral hippocampi which are remote from the ischemic MCA region. These data show that changes in neurotrophic factor and receptor gene expressions can occur in the areas outside the infarct which could survive.

Animals↗

PubMed1996

Astroglial cells inhibit the increasing permeability of brain endothelial cell monolayer following hypoxia/reoxygenation.

Blood-brain barrier (BBB) is known to be structured with astroglial cells (AGs) and brain endothelial cells (BECs), and it has been proposed that these cells play different roles in the BBB. We cultivated AGs and BECs from infant rats (2-week-old), and these cells were cultured on the opposing side of collagen membrane to produce a co-culture model of the BBB in vitro. Permeability of the cell layer was evaluated by the electrical resistance through the membrane. To clarify the role of AGs in the BBB disruption following ischemia/reperfusion, electrical resistance of the co-culture model was compared to that of BEC monolayer following hypoxia/reoxygenation. The electrical resistance through BEC monolayer showed 55.5 +/- 15.1 percent reduction at 4 h of hypoxia, and 93.3 +/- 5.4 percent reduction at 8 h of hypoxia (n = 8). However, the co-culture model showed attenuation of the reduction (24.8 +/- 14.2 percent) at 4 h of hypoxia (n = 8, P < 0.01), but not at 8 h of hypoxia (95.3 +/- 5.0 percent). These results indicate that AGs reduce the increasing permeability of the BEC monolayer following short duration of hypoxia/reoxygenation. It is suggested that AGs may have a protective effect to the BBB disruption following ischemia/reperfusion.

Animals↗

PubMed1996

Changes in concentrations of methylglyoxal, D-lactate and glyoxalase activities in liver and plasma of rats fed a 3'-methyl-4-dimethylaminoazobenzene-rich diet.

Donryu male albino rats were fed a diet containing 0.064% 3'-methyl-4-dimethylaminoazobenzene (MDAB) for 21 weeks. During the ensuing rat liver carcinogenesis, changes in the concentrations of methylglyoxal, D-lactate and glutathione as well as activities of glyoxalase I and II in liver and plasma were examined. After the start of the diet, hepatic contents of methylglyoxal and D-lactate increased to about 7 and 3 times that of the control, respectively. However, after 21 weeks the D-lactate content decreased from the elevated level, but remained at a higher level of 1.4 times the control. The hepatic glyoxalase I activity increased 1.2 to 1.7 times over the control during carcinogenesis, while glyoxalase II activity increased 160% during the precancerous state and decreased to 55% of control at 21 weeks. the hepatic level of reduced glutathione (GSH) increased and peaked after 4 weeks of the MDAB diet and decreased thereafter to 57% of the control level after 21 weeks. Both pyruvate and L-lactate levels increased in the liver and plasma of MDAB-fed rats when rats had obvious symptoms of hepatoma.

Alanine Transaminase↗

PubMed1996

Spinal malignant lymphoma appearing after radiation and chemotherapy of a pineal region tumor.

The occurrence of malignant lymphoma in the pineal region is very rare. We experienced a case of pineal region tumor that was treated by radiation and chemotherapy. After 1 year, the tumor metastasized to the cauda equina and was operated on. The diagnosis was malignant lymphoma. Although the incidence of intracranial malignant lymphoma is known to be on the increase recently, malignant lymphoma should be considered in the differential diagnosis of pineal region tumors.

Adolescent↗

PubMed1996

Reconstruction of dilated aortic annulus using short tubular Dacron graft for aortic root replacement by aortic homograft--a solution for size mismatch.

To circumvent the problems associated with a dilated aortic annulus we first reduced the diameter of the annulus with a short section of Dacron graft and then implanted a smaller size homograft within the graft. This procedure was successfully performed for complete homograft aortic root replacement in a 25-year-old man with severe aortic insufficiency due to a dilated aortic annulus. The indication for homograft replacement can thus be widened, even to patients with a dilated aortic annulus.

Adult↗

PubMed1996

[Left free wall rupture complicating acute myocardial infarction--a case report of surgical success by a new modified method].

The success rate of surgical treatment for blowout type free wall rupture of the left ventricle following myocardial infarction has been reported as 4 to 24%. A 64-year-old woman was admitted to our hospital for inferior acute myocardial infarction with cardiogenic shock. In the catheter laboratory, her hemodynamics disclosed electro-mechanical dissociation, and we had to perform an emergent operation there. In order to preserve left ventricular volume and reduce the risk of bleeding, we adopted a modified method using both patch and felt strip sandwich methods which obtained favorable result. The patient was sent to a rehabilitation hospital on the 43rd post operative day because of a mild cerebral complication and she is now doing well with only a slight speaking disturbance at a follow-up period of 10 months.

Cardiac Surgical Procedures↗

PubMed1995

Contents of D-lactate and its related metabolites as well as enzyme activities in the liver, muscle and blood plasma of aging rats.

As it is generally known. L-lactate is formed via the Embden-Meyerhof glycolytic pathway from triosephosphates, whereas D-lactate is formed via methylglyoxal in rat. In this paper, age-related changes in the levels of D-lactate and its related compounds in rat tissues are reported. Rats from 5 weeks to 30 months old were used in these experiments. (1) We observed that rats above 27 months old were decrepit as judged by external appearance movement and other physiological data of them. (2) The hepatic levels of D-lactate, methylglyoxal and pyruvate became markedly lower in aging rats, especially the D-lactate content in 30 month-old rats was lower by 90% than that of the 5 week-old rats. (3) As for plasma, D-lactate and phosphate levels became lower with aging, whereas levels of L-lactate and pyruvate were not altered. (4) In skeletal muscle, aging caused a lower methylglyoxal concentration. The D-lactate level was markedly decreased at the age of 30 months in muscle. (5) As for enzyme, activities of glyoxalase I and II became markedly decreased with age in livers, whereas the activity of glyoxalase I in muscle was maintained at control level and glyoxalase II increased with age.

Aging↗

PubMed1995

Most of the VP1 unique region of B19 parvovirus is on the capsid surface.

B19 parvovirus is pathogenic in man and a vaccine is desirable. In convalescence after acute infection, the dominant humoral immune response is directed to the minor capsid protein called VP1, which differs from the major capsid protein by an additional NH2-terminal 227 amino acids. We have previously shown that this unique region contains multiple linear neutralizing epitopes. We produced seven recombinant B19 capsids that contained progressively truncated VP1 unique region sequences, each fused to a Flag peptide (AspTyrLysAspAspAspAspLys) at the NH2-terminus. Capsids containing normal VP2 and truncated Flag-VP1 proteins and, in some cases, only truncated Flag-VP1 chimeric proteins, were analyzed by ELISA, affinity chromatography, and electron microscopy using anti-Flag monoclonal antibody. All regions examined showed binding to anti-Flag antibody in multiple assays, indicating that most of the VP1 unique region is external to the capsid and accessible to antibody binding. These results have implications for the design of a B19 parvovirus vaccine and the use of empty capsids for presentation of heterologous protein antigens.

Amino Acid Sequence↗

PubMed1995

Peptides derived from the unique region of B19 parvovirus minor capsid protein elicit neutralizing antibodies in rabbits.

B19 parvovirus is pathogenic in humans. The virus propagates in the bone marrow, where it is cytotoxic to erythroid progenitor cells. Antibodies appear in blood after infection and neutralize virus in vitro; infection appears to confer lasting immunity. The predominant immune response on immunoblot is to the minor capsid protein (VP1), which differs from the major capsid protein (VP2) by an additional 227 amino acids. We previously demonstrated that antisera directed to a fusion protein containing this unique region or to more limited fusion peptides of 50-100 amino acids each neutralized virus. In the current work, we tested synthetic peptides of about 20 amino acids derived from the VP1 unique region for their ability to elicit a neutralizing antibody response in rabbits. Individual peptides were covalently linked to a lysine core to produce a multivalent antigen. Animals produced antibodies to all 13 synthetic peptides, as determined by ELISA. At 12 weeks, animals injected with one of three peptides--two from the far amino terminus and the third from the center of the unique region--had produced antibodies that completely neutralized virus; by 16 weeks, antisera elicited with another four peptides also were effective. In summary, we identified regions containing neutralizing epitopes within the first 80 amino acids and amino acids 148-205 of the unique region. Our data suggest that synthetic peptides might be useful vaccine reagents for protection against parvovirus infection in humans.

Amino Acid Sequence↗

PubMed1995

Purification of functional recombinant YY1 expressed in Sf9 insect cells.

We expressed a gene for YY1, the multifunctional mammalian transcription factor, with a recombinant baculovirus in insect cells and obtained high levels of protein in cell lysates. A simple and efficient purification method was developed. In the final step, we used DNA affinity chromatography with concatermerized sequence derived from the upstream region of the B19 parvovirus P6 promoter, which has strong affinity for YY1. Approximately 1.8 mg of highly purified YY1 was obtained from 10(9) Sf9 cells. Highly purified YY1 behaved as authentic YY1 on electrophoretic mobility shift assays and in enhancing transcription from the P6 promoter. YY1 produced in a baculovirus system should prove useful for in vitro transcription assays of YY1 and related regulatory proteins.

Animals↗