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R Nagai

Publications and source records attributed to R Nagai.

At least 145 records · Page 8Linked to original sources
PubMed2000

Effect of interleukin-18 on viral myocarditis: enhancement of interferon- gamma and natural killer cell activity.

Encephalomyocarditis virus causes viral myocarditis with myocyte necrosis and inflammatory cell infiltration in mice. Because previous studies have shown that some cytokines prevent the sequelae of myocarditis, we assessed the effect of a newly identified cytokine, interleukin-18 (IL-18), in preventing the sequelae of myocarditis. Murine IL-18 (10 microg/day/mouse) was given peritoneally for 10 days in C3H mice infected with EMC virus. Mice were divided into group IL-18 (infected-treated), saline group (infected-untreated), group IL-18-2 (treatment started on day 2), group IL-18-5 (treatment started on day 5). Although the 14-day survival rate in saline group was 20%, that in the group IL-18 increased to 80% (P<0.05). Either mice in group IL-18-2 or in group IL-18-5 did not survive longer than saline group. The viral titer of the heart on day 3 was lower in group IL-18 compared to the saline group (1.00+/-0.20 log(10)tissue culture infected dose (TCID)(50)/mg wet weight v 1.42+/-0.12 log(10)TCID(50)/mg, n=3 of each). Mice in group IL-18 had less myocardial necrosis and cellular infiltration than the saline group. The myocardial expression of interferon- gamma (IFN- gamma) mRNA in group IL-18 was significantly (P<0.05) greater than the saline group on days 1 and 3 after viral inoculation. Circulating IFN- gamma was significantly elevated on days 1, 5, and 7, but significantly reduced on day 3. The natural killer cell activities in the spleen on days 1, 3, and 5 were significantly (P<0.05) greater in group IL-18 than in the saline group (41+/-9%v 10+/-6% on day 3, 4 of each). We conclude that IL-18 reduces the severity of EMC viral myocarditis by inducing cardiac expression of IFN- gamma mRNA and increasing splenic natural killer cell activity.

Animals↗
PubMed2000

Endothelial dysfunction in the klotho mouse and downregulation of klotho gene expression in various animal models of vascular and metabolic diseases.

The human aging process is associated with vascular endothelial dysfunction. However, humoral factors which might protect against endothelial dysfunction during aging have not yet been identified. We recently identified the klotho gene as a possible regulator of human aging. In the present study using the klotho-deficient heterozygous mouse, we examined whether the Klotho protein is a humoral factor protecting against endothelial dysfunction. We further cloned rat klotho cDNA and investigated whether klotho mRNA expression in rat kidney is altered under pathological conditions such as hypertension, hyperlipidemia, renal failure, and inflammatory stress. The Klotho protein itself, or its metabolites, promotes endothelial NO production in aorta as well as arterioles, and klotho mRNA in kidney is downregulated under sustained circulatory stress.

Acetylcholine↗
PubMed2000

Advanced glycation endproduct-modified superoxide dismutase-1 (SOD1)-positive inclusions are common to familial amyotrophic lateral sclerosis patients with SOD1 gene mutations and transgenic mice expressing human SOD1 with a G85R mutation.

To clarify the biological significance of the neuronal Lewy body-like hyaline inclusions and astrocytic hyaline inclusions characteristically found in patients with familial amyotrophic lateral sclerosis with superoxide dismutase-1 (SOD1) gene mutations and in transgenic mice expressing human SOD1 with G85R mutation, the detailed protein composition in both types of inclusions was immunohistochemically analyzed using 45 different antibodies. Both types of inclusions had very strong immunoreactivity for SOD1. The SOD1-positive inclusions in both cell types were also immunoreactive for the insoluble advanced glycation endproducts (AGEs) such as Nepsilon-(carboxymethyl)lysine (CML), pyrraline and pentosidine: both inclusions in both conditions were ultrastructurally composed of the granule-coated fibrils that had immunoreactivities to CML and pyrraline. Both types of inclusions were negative for stress-response proteins (SRPs), 4-hydroxy-2-nonenal (HNE), acrolein, nitric oxide synthases (NOSs) and nitrotyrosine as representative markers of oxidative stress. The neurons and astrocytes of the normal individuals and non-transgenic mice showed no significant immunoreactivity for SOD1, AGEs, SRPs, HNE, acrolein, NOSs or nitrotyrosine. Our results suggest that a portion of the SOD1 composing both type of inclusions, probably toxic mutant SOD1, is modified by the AGEs, and that the formation of the AGE-modified SOD1 is one of the mechanisms responsible for the aggregation involving no significant oxidative mechanisms.

Adult↗
PubMed2000

Nonoxidative protein glycation is implicated in familial amyotrophic lateral sclerosis with superoxide dismutase-1 mutation.

To assess a role for oxidative stress in the pathogenesis of amyotrophic lateral sclerosis (ALS), we analyzed the immunohistochemical localization of 8-hydroxy2'-deoxyguanosine (OHdG) as a nucleic acid oxidation product, acrolein-protein adduct and 4-hydroxy-2-nonenal (HNE)-protein adduct as lipid peroxidation products, Nepsiloncarboxymethyl-lysine (CML) as a lipid peroxidation or protein glycoxidation product, pentosidine as a protein glycoxidation product, and imidazolone and pyrraline as nonoxidative protein glycation products in the spinal cord of three familial ALS patients with superoxide dismutase(SOD 1) A4V mutation, six sporadic ALS patients, and six age-matched control individuals. The spinal cord sections of the control cases did not show any distinct immunoreactivities for these examined products. In the familial ALS cases, intense immunoreactivities for pyrraline and CML were confined to the characteristic Lewy body-like hyaline inclusions, and imidazolone immunoreactivity was located in the cytoplasm of the residual motor neurons. No significant immunoreactivities for other examined products were detected in the familial ALS spinal cords. In the sporadic ALS cases, intense immunoreactivities for pentosidine, CML and HNE-protein adduct were seen in the cytoplasm of the degenerated motor neurons, and OHdG immunoreactivity was located in the cell nuclei of the residual neurons and glial cells. The present results indicate that oxidative reactions are involved in the disease processes of sporadic ALS, while there is no evidence for increased oxidative damage except for CML deposition in the familial ALS spinal cords. Furthermore, it is likely that the accumulation of pyrraline and imidazolone supports a nonoxidative mechanism in SOD1-related motor neuron degeneration.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Twenty single nucleotide polymorphisms (SNPs) and their allelic frequencies in four genes that are responsible for familial long QT syndrome in the Japanese population.

We report here 20 single nucleotide polymorphisms (SNPs), including 10 novel ones, and their allelic frequencies detected in four genes that are known to be responsible for familial long QT syndrome in the Japanese population; 7 polymorphisms are in the KCNQ1 gene, 6 in the KCNH2 gene, 5 in the SCN5A gene, and 2 in the KCNE1 gene. These data will be of use for genetic association studies of acquired cardiac arrhythmias.

Alleles↗
PubMed2000

Simple and practical sandwich-type enzyme immunoassay for human oxidatively modified low density lipoprotein using antioxidized phosphatidylcholine monoclonal antibody and antihuman apolipoprotein-B antibody.

OBJECTIVES: To develop a simple and practical enzyme immunoassay (EIA) for oxidatively modified low density lipoprotein (Ox-LDL) in human blood, a biological marker of atherogenesis. DESIGN AND METHODS: A sandwich EIA suitable for the measurement of human Ox-LDL was developed using the mouse monoclonal antibody FOH1a/DLH3. This antibody, specific for oxidized phosphatidylcholine, was used as the capture antibody, and a horseradish peroxidase (HRP)-labeled goat anti-human apolipoprotein-B (Apo-B) IgG was used for detection. Copper-oxidized human LDL, prepared under controlled conditions, was used as a standard and the results of the EIA were expressed in arbitrary units (U/mL). RESULTS: This EIA meets all the requirements for use in routine clinical assays in terms of sensitivity (detection limit: 1 U/mL), reproducibility (total CV: 2.3-7.7%), accuracy (recovery: 90.6-103.8%), simplicity and rapidity (<4 h). Clinical performance of the assay was assessed by measurement of the Ox-LDL in the plasma of normal subjects (10.8 +/- 2.8 U/mL, mean +/- SD) and patients with coronary heart disease (CHD) (19.7 +/- 10.2). The present EIA had a sensitivity of 79% and a specificity of 75% for CHD. CONCLUSIONS: We have developed a new assay, suitable for the measurement of Ox-LDL in human blood, which meets the requirements for routine clinical assay.

Adult↗
PubMed2000

Serum level of vascular endothelial growth factor is decreased by hormone replacement therapy in postmenopausal women without hypercholesterolemia.

The administration of hormone replacement therapy (HRT) to postmenopausal women (PMW) reportedly has beneficial effects on their levels of lipid and lipoproteins. Estrogen retards the development of atherosclerosis induced by a high-fat diet in animals. Although vascular endothelial growth factor (VEGF) may be involved in the development of atherosclerosis in humans, there is no information on effect of estrogen administration on VEGF level and lipid metabolism. We evaluated 64 healthy normotensive or hypertensive PMW before and during the administration of HRT (0.625 mg conjugated equine estrogen combined with 2.5 mg medroxyprogesterone acetate orally) daily for 6 months. All hypertensive PMW were well-controlled on antihypertensive drug therapy. According to their total cholesterol level at baseline, we divided the PMW with HRT (n=54) into a normocholesterolemic group (NC, total cholesterol <220 mg/dl, n=35) and a hypercholesterolemic group (HC, total cholesterol >/=220 mg/dl, n=19). We evaluated the serum levels of VEGF at baseline, and again at 3 and 6 months after starting HRT. HRT significantly (P<0.01) reduced the mean VEGF level from 31.5+/-4.3 pg/ml at baseline to 18.2+/-2.3 pg/ml after 6 months in the NC group. However, the VEGF levels in the HC group and the control group exhibited no significant change at either 3 or 6 months after starting HRT. In summary, HRT, using a combination of conjugated equine estrogen and medroxyprogesterone acetate, reduced the level of VEGF in normocholesterolemic PMW more effectively than in those with hypercholesterolemia.

Aged↗
PubMed2000

In vivo and in vitro evidence for the glycoxidation of low density lipoprotein in human atherosclerotic plaques.

Although there have been suggestions that the glycation and oxidation of low density lipoprotein (LDL) might increase its atherogenic potential, little is known about the presence of glycoxidative LDL in human atherosclerotic lesions. We developed specific antibodies against different immunological epitopes of AGE structures, including N(epsilon)-(carboxymethyl)lysine-protein adduct (CML), a glycoxidation product, and structure(s) other than CML (nonCML), and a monoclonal antibody against oxidized phosphatidylcholine (oxPC), as an epitope of oxidized LDL. Immunohistochemical analysis demonstrated that the CML- and oxPC-epitopes were accumulated mainly in macrophage-derived foam cells in atherosclerotic lesions, including fatty streaks and atherosclerotic plaques. On the other hand, the nonCML-epitope and apolipoprotein B were localized mainly in extracellular matrices of atherosclerotic lesions. The CML- and oxPC-epitopes were characterized by a model antigen-generating system using the copper ion-induced peroxidation and/or glucose-induced glycation of LDL. The glycoxidation of LDL caused the formation of CML-epitope with increasing concentrations of copper ion and glucose. It was also formed to some extent in LDL incubated with high concentrations (500 mM) of glucose. However, no CML-epitope was observed in oxidized LDL induced by copper ion alone. On the other hand, the formation of oxPC-epitope in LDL was dependent on copper ion-induced peroxidation, but independent of glucose-induced glycation. The addition of chelators, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, reduced the increase in electrophoretic mobility and TBARS caused by the peroxidation and glycoxidation of LDL, but had no effects on the formation of fructosamine caused by the glycation and glycoxidation of LDL. Chelators as well as aminoguanidine protected the formation of CML-epitope in glycated or glycoxidative LDL. Although the formation of oxPC-epitope was completely inhibited by the addition of chelators, it was partially protected by aminoguanidine. These in vitro results suggest that the glycoxidative modification of LDL may occur in the arterial intima, and may contribute to the development of human atherosclerotic lesions.

Adolescent↗
PubMed2000

Inducible expression of basic transcription element-binding protein 2 in proliferating smooth muscle cells at the vascular anastomotic stricture.

OBJECTIVE: The proliferation of vascular smooth muscle cells surrounding a suture line is an important factor in the development of anastomotic stricture that is frequently seen after coronary artery bypass grafting. The aim of this study was to investigate the time course of intimal thickening and to examine the expression of the molecular marker of smooth muscle cell activation surrounding the suture line. METHODS: Longitudinal aortotomy was performed in the abdominal aorta of rats. The rats were put to death 1, 2, 4, and 8 weeks after aortotomy, and the percentage of the lumen occluded by intimal thickening was calculated. All tissues were stained with antibodies against basic transcription element- binding protein 2, human cyclin-dependent kinase (cdk4), and Sp1 for immunohistochemistry. Basic transcription element-binding protein 2 is a transcription factor that is involved in phenotypic modulation of vascular smooth muscle cells. Cdk4 represents a marker for G(1) phase of the cell cycle. Sp1 is a transcription factor known to be expressed in a variety of tissues. Basic transcription element-binding protein 2 messenger RNA expression was confirmed by means of reverse transcriptase-polymerase chain reaction. RESULTS: We noted significant thickening of the intimal layer 1 week after aortotomy. Immunohistochemistry demonstrated that smooth muscle cells in the neointima were strongly positive for basic transcription element-binding protein 2 and human cyclin-dependent kinase 4, which peaked 2 weeks after aortotomy. Basic transcription element-binding protein 2 expression was closely associated with human cyclin-dependent kinase 4 expression in the neointima, although Sp1 was not. Basic transcription element-binding protein 2 messenger RNA levels were significantly up-regulated early after aortotomy. CONCLUSION: The experimental rat aortotomy model is useful to investigate the proliferation of vascular smooth muscle cells around the suture line. Moreover, our results suggest the possible role of basic transcription element-binding protein 2 in the development of vascular anastomotic strictures.

Anastomosis, Surgical↗
PubMed2000

Selective vulnerability to radiation in the hippocampal dentate granule cells.

BACKGROUND: Radiation therapy is an effective approach in the treatment of highly radiosensitive brain tumors such as germinomas. However, recent studies have reported intellectual disturbances in patients who underwent whole-brain irradiation as children. We detected apoptosis in the infantile murine cerebrum after systemic X-ray irradiation. METHODS: Subjects were 100 ICR mice 4 weeks old, of which 90 were systemically exposed to 18 Gy X-rays (0.45 Gy/min); 10 each were decapitated and the cerebrums were removed 1, 3, 6, 9, 12, 18, 24, 48, and 72 hours after irradiation. Controls were 10 unirradiated mice. DNA fragmentation analysis was carried out by agarose gel electrophoresis, and morphological analysis was by the TUNEL method. RESULTS: According to agarose gel electrophoresis, the cerebral DNA ladders were detected only over 6 to 24 hr, peaking in 9 hr. Even at the peak, band intensity was nearly double that of the unirradiated normal thymus. According to the TUNEL analysis, radiation-induced apoptosis increased, with a peak at 9 hours, but decreased 24 hours after irradiation. Apoptotic cells were always localized exclusively in the hippocampal dentate granule cells. CONCLUSIONS: We found that vulnerability to radiation existed in the hippocampal dentate granule cells. Intellectual disturbances in patients who have undergone whole-brain irradiation may be caused by injury to the hippocampus.

Acute Disease↗
PubMed2000

Bile acids increase intracellular Ca(2+) concentration and nitric oxide production in vascular endothelial cells.

The effects of bile acids on intracellular Ca(2+) concentration [Ca(2+)](i) and nitric oxide production were investigated in vascular endothelial cells. Whole-cell patch clamp techniques and fluorescence measurements of [Ca(2+)](i) were applied in vascular endothelial cells obtained from human umbilical and calf aortic endothelial cells. Nitric oxide released was determined by measuring the concentration of NO(2)(-). Deoxycholic acid, chenodeoxycholic acid and the taurine conjugates increased [Ca(2+)](i) concentration-dependently, while cholic acid showed no significant effect. These effects resulted from the first mobilization of Ca(2+) from an inositol 1,4,5-triphosphate (IP(3))-sensitive store, which was released by ATP, then followed by Ca(2+) influx. Both bile acids and ATP induced the activation of Ca(2+)-dependent K(+) current. Oscillations of [Ca(2+)](i) were occasionally monitored with the Ca(2+)-dependent K(+) current in voltage-clamped cells and Ca(2+) measurements of single cells. The intracellular perfusion of heparin completely abolished the ATP effect, but failed to inhibit the bile acid effect. Deoxycholic acid and chenodeoxycholic acid enhanced NO(2)(-) production concentration-dependently, while cholic acid did not enhance it. The bile acids-induced nitric oxide production was suppressed by N(G)-nitro-L-arginine methyl ester, exclusion of extracellular Ca(2+) or N-(6-aminohexyl)-5-chloro-l-naphthalenesulphonamide hydrochloride (W-7) and calmidazolium, calmodulin inhibitors. These results provide novel evidence showing that bile acids increase [Ca(2+)](i) and subsequently nitric oxide production in vascular endothelial cells. The nitric oxide production induced by bile acids may be involved in the pathogenesis of circulatory abnormalities in liver diseases including cirrhosis.

Animals↗
PubMed2000

Regulation of interaction of the acetyltransferase region of p300 and the DNA-binding domain of Sp1 on and through DNA binding.

BACKGROUND: The coactivator p300 acts as a transcriptional adaptor for many DNA-binding activators. The finding that p300 possesses intrinsic acetyltransferase activity which, by chemically modifying histone tails affects the nucleosomal environment and transcription, has greatly advanced our understanding of its function. Subsequent recent studies have shown that non-histone proteins are also acetylated. However, one central question which has remained unanswered is how the coactivator/acetyltransferase interacts with DNA-binding activators to modulate their actions. RESULTS: Here we have demonstrated physical and functional interaction between the acetyltransferase region of p300 and the DNA-binding domain (DBD) of the transcription factor Sp1. This interaction stimulates DNA binding by the DBD of Sp1, which is mediated primarily by physical interaction rather than acetylation, despite acetylation of the DBD of Sp1 by the acetyltransferase region of p300. Furthermore, DNA binding by the DBD of Sp1 inhibits both its association and acetylation by the acetyltransferase region of p300. CONCLUSIONS: These findings suggest a new role for p300 in regulating promoter access by DNA-binding activators through multiple regulatory interactions.

Acetylation↗
PubMed2000

Targeted disruption of the homeobox transcription factor Bapx1 results in lethal skeletal dysplasia with asplenia and gastroduodenal malformation.

BACKGROUND: NK homeobox genes have been shown to play important roles in cell-type specification and organogenesis. Murine Bapx1, a member of NK homeobox gene family, is expressed in all the cartilageous tissues that undergo endochondral bone formation, and in gut mesentery during embryogenesis, suggesting that Bapx1 may be a key transcription factor ragulating the development of these organs. RESULTS: We generated Bapx1-deficient mice by gene targeting. Bapx1-/- mice exhibited lethal skeletal dysplasia, with abnormal development of the vertebral column and some craniofacial bones, accompanied with asplenia and gastroduodenal malformation. We showed that the proliferative activity of the sclerotome cells, forming the vertebral column, was significantly reduced in Bapx1-/- embryos. The sclerotome cells of the mutants appeared to migrate and condense normally, but subsequent differentiation into the mature vertebral bodies and intervertebral discs were affected. The sclerotome cells in the vertebral bodies failed to differentiate into hypertrophic chondrocytes, as revealed by the undetected expression of Col10a1 and Osteopontin, and the sclerotome cells in the intervertebral discs failed to express the typical extracellular matrix proteins Col2a1, Col9a2 and aggrecan. Furthermore, we investigated the effect of loss of Bapx1 on the expression of some transcription factors, identified to be expressed in the developing sclerotome and be required for normal development of the vertebral column. Among them, we found that the expression of MFH-1 (mesenchyme forkhead-1), which was reported to regulate the proliferation and differentiation of sclerotome cells, was significantly reduced in ventromedial sclerotome cells in Bapx1-/- mice. CONCLUSION: Our analysis provided evidence that Bapx1 was indispensable for normal development of ventromedial structure of vertebral column and some of craniofacial bones, splenogenesis and morphogenesis of gastroduodenal tract.

Abnormalities, Multiple↗
PubMed2000

Advanced glycation end product in familial amyloidotic polyneuropathy (FAP).

OBJECTIVES: Advanced glycation end products (AGE) are present in amyloid deposits in beta2-microglobulin amyloidosis, and it has been postulated that glycation of beta2-microglobulin may be involved in fibril formation. The aim of this paper was to ascertain whether AGE occur in amyloid deposits in familial amyloidotic polyneuropathy (FAP). SETTING: Department of Medicine, Umeå University Hospital and First Department of Internal Medicine, Kumamoto University School of Medicine. DESIGN: The presence of AGE was sought immunohistochemically and biochemically in amyloid-rich tissues from patients with FAP. SUBJECTS: Biopsy specimens from nine patients and 10 controls were used for the immunohistochemical analysis. For amyloid preparation, vitreous samples from three FAP patients were used. RESULTS: Immunohistochemical studies using a polyclonal anti-AGE antibody revealed positive immunoreactivity in intestinal materials, but the pattern of reactivity was unevenly distributed; it was often present in the border of amyloid deposits, or surrounding them. Non-amyloid associated immunoreactivity was also observed in a few regions of the specimens, although the AGE-positive structures were situated in areas containing amyloid deposits. Western blotting of purified amyloid from the vitreous body of FAP patients revealed a significant association of AGE with amyloid fibrils. CONCLUSION: The immunoreactivity for the AGE antibody suggests that AGE may be involved in fibril formation in FAP.

Adult↗
PubMed2000

Pleural amyloidosis in a patient with intractable pleural effusion and multiple myeloma.

Pleural involvement of systemic amyloidosis has been rarely reported. We report a case with multiple myeloma presenting an intractable right pleural effusion, in which pleural amyloidosis was diagnosed through pleural biopsy using a Cope needle. The diagnosis of pleural amyloidosis is important, because its refractory pleural effusion should be treated with pleurodesis. Since closed pleural biopsy using a Cope needle is much less invasive than thoracoscopy, the former should be attempted first whenever pleural amyloidosis is suspected.

Aged↗