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Biomedical subjects

Mitsuru Seishima

Publications and source records attributed to Mitsuru Seishima.

At least 37 records · Page 2Linked to original sources
PubMed2004

Role of tumor necrosis factor-alpha in methamphetamine-induced drug dependence and neurotoxicity.

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is now emerging as an important modulator of the function of the CNS. Methamphetamine (METH) is a widely abused psychostimulant that causes euphoria, hyperactivity, and drug dependence. High doses of METH cause long-term neurotoxicity in dopaminergic neurons. In this study, we investigated a role of TNF-alpha in METH-induced dependence and neurotoxicity. Repeated treatment with METH (2 mg/kg for 5 d) in rats induced a significant increase in TNF-alpha mRNA and protein expression in the brain. Exogenous TNF-alpha (1-4 microg) blocked locomotor-stimulating and rewarding effects of METH, as well as METH (4 mg/kg; four times at 2 hr intervals)-induced dopaminergic neurotoxicity in mice. To examine a role of endogenous TNF-alpha in behavioral and neurochemical effects of METH, we used mice with targeted deletions of the TNF-alpha gene. TNF-alpha-(-/-) mice showed enhanced responses to the locomotor-sensitizing, rewarding, and neurotoxic effects of METH compared with wild-type mice. We also examined the role of TNF-alpha in METH-induced dopamine (DA) release and uptake in vitro and in vivo in C57BL/6 mice. Exogenous TNF-alpha (4 microg) attenuated the METH-induced increase in extracellular striatal DA in vivo and potentiated striatal DA uptake into synaptosomes in vitro and in vivo. Furthermore, TNF-alpha activated vesicular DA uptake by itself and diminished the METH-induced decrease in vesicular DA uptake. Our findings suggest that TNF-alpha plays a neuroprotective role in METH-induced drug dependence and neurotoxicity by activating plasmalemmal and vesicular DA transporter as well as inhibiting METH-induced increase in extracellular DA levels.

Animals↗
PubMed2004

Non-steroidal anti-inflammatory drugs inhibit cellular proliferation and upregulate cyclooxygenase-2 protein expression in endometrial cancer cells.

We determined the effects of several non-steroidal anti-inflammatory drugs (NSAIDs), aspirin (acetylsalicylic acid, ASA), indomethacin and a cyclooxygenase-2 (COX-2)-selective inhibitor (NS398), on cellular proliferation and regulation of COX-2 protein expression in endometrial cancer cells in vitro, and investigated their modes of action. All three NSAIDs markedly inhibited the proliferation of Ishikawa, HEC-1A and AN3CA endometrial cancer cell lines in a time- and concentration-dependent manner. ASA and indomethacin triggered apoptosis in cells of all three lines through release of cytosolic cytochrome c, activation of caspase-9 and-3, and cleavage of poly(ADP-ribose) polymerase (PARP), but NS398 induced minimal apoptosis only in Ishikawa cells. ASA altered the cell cycle distribution, with G2/M phase accumulation of cells, and induced overexpression of Ki-67 protein. Both ASA and indomethacin reduced the protein levels of Bcl-2 and Bcl-xl, but upregulated those of Bax and Bcl-xs. COX-2 protein expression and PGE(2) production were upregulated by ASA and indomethacin in all three cell lines. However, NS398 did not alter COX-2 protein expression or PGE(2) production in these cells. These results indicate that NSAIDs inhibit proliferation of endometrial cancer cells independently of the reduction of COX-2 protein expression. A cytochrome c-dependent apoptotic pathway and/or cell cycle arrest may contribute to the inhibitory effects of these NSAIDs.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Genotyping of hepatitis C virus by melting curve analysis with SYBR Green I.

BACKGROUND: Recent studies have focused on whether different hepatitis C virus (HCV) genotypes are associated with different profiles of pathogenicity, infectivity, and response to antiviral therapy. We needed to develop a convenient screening test for HCV genotypes 1 and 2. METHOD: We tested 55 patients with known chronic HCV infection. Viral RNA was extracted from serum samples using an automatic viral RNA purification system, and HCV genotypes were determined by reverse transcriptase-polymerase chain reaction using LightCycler melting curve analysis with SYBR Green I. RESULTS: HCV RNA was detected in all samples and each genotype was determined. The mean (standard deviation) melting temperatures for subtypes 1b (n = 32), 2a (n = 15) and 2b (n = 8) were 93.14 degrees C (0.51 degrees C), 91.08 degrees C (0.49 degrees C) and 91.77 degrees C (0.27 degrees C), respectively. Genotypes 1 and 2 were differentiated within 3 h by this method. CONCLUSIONS: Our melting curve analysis is a rapid and convenient screening test for differential identification of HCV genotypes 1 and 2.

Benzothiazoles↗
PubMed2004

Interferon-gamma produced by bone marrow-derived cells attenuates atherosclerotic lesion formation in LDLR-deficient mice.

BACKGROUND: We evaluated the role of IFN-gamma produced by bone marrow-derived cells in atherogenesis in LDLR(-/-) mice using bone marrow transplantation (BMT). METHODS AND RESULTS: We generated IFN-gamma-deficient bone marrow transplanted LDLR(-/- )mice (IFN-gamma(-/-) BMT mice), and compared them with controls (IFN-gamma(+/+) BMT mice). These mice were fed a high-fat diet (HFD). Plasma total cholesterol and triglyceride levels did not differ between these two groups. After 6 weeks of HFD feeding, the atherosclerotic lesions of IFN-gamma(-/-) BMT mice were larger than those of IFN-gamma(+/+) BMT mice at the aortic sinus, aortic arch and abdominal aorta. After 12 weeks of HFD feeding, the significant differences between the two groups disappeared except for the atherosclerotic lesion in the aortic sinus. MOMA2, CD4, CD8 or alpha-smooth muscle actin-positive cells were detected in the atherosclerotic lesions. The cellular composition of the lesions was identical between the two groups, but the cellular density showed decreased concomitant with the increased extracellular matrix deposition in IFN-gamma(-/- )BMT mice. CONCLUSIONS: These findings demonstrate that IFN-gamma produced by bone marrow-derived cells delays the progression of atherosclerosis without any effect on plasma lipids, and this suppression may be due to decreased extracellular matrix deposition.

Animals↗
PubMed2004

[Clinical significance of serum IL-18 determination in rheumatoid arthritis].

Interleukin (IL)-18 is a novel cytokine expressing at inflammatory lesion. In this study, to evaluate the clinical significance of IL-18 determination, we have examined serum IL-18, inflammation markers, sFas, and sFas-ligand concentrations in patients with rheumatoid arthritis(RA). Serum was obtained from 56 RA patients aged 35-74 years, 16 osteoarthritis (OA) patients aged 36-78 years and 178 healthy subjects aged 20-72 years and IL-18 was measured by ELISA. Serum IL-18 concentrations in RA (240.1 +/- 15.6 pg/ml, mean +/- SE) were significantly higher than OA (151.8 +/- 12.7 pg/ml, p < 0.005) and healthy controls(141.5 +/- 26.1 pg/ml, p < 0.001). Serum IL-18 levels were significantly increased in II to IV stages of RA (stage II; 218.6 +/- 31.2 pg/ml, stage III; 258.7 +/- 38.4 pg/ml, stage IV; 231.6 +/- 13.1 pg/ml) than those in OA. Furthermore, a positive correlation was observed between serum IL-18 concentration and serum Fas level in patients with RA (r = 0.472), whereas there was no significant correlation between serum IL-18 and sFas-ligand or other inflammatory markers (CRP, RF, CA-RF, IL-6, and IL-8). The present study showed that serum IL-18 level increased in RA, but it is unknown how IL-18 is involved in the pathogenesis of RA. Further study will be necessary to clarify the role of IL-18 in RA.

Adult↗
PubMed2004

[Genotyping and the quantification of hepatitis C virus by the melting curves in light cycler].

Detection of the HCV genome is crucial for diagnosis of HCV infection and for monitoring the efficacy of interferon treatment for patients with HCV. We developed a convenient screening test for HCV genotypes 1 and 2 based on the melting curve analysis with SYBER green I. Serum samples were drawn from 114 patients with known chronic HCV infection confirmed to be antibody-positive by immunoblot assay. A characteristic melting profile for each genotype was obtained by monitoring the fluorescence as the temperature increases through the melting point of the PCR product. Serum samples with HCV-RNA genotype (1b, 2a and 2b) were analyzed every test as standard samples and the genotype of unknown samples was determined by the comparison with the melting point of standard samples. Serum samples with known HCV-RNA genotype (1b, 2a and 2b) and HCV-RNA-negative sample were tested using the Light cycler system. The melting curve analysis indicated that melting points are 93.08 +/- 0.56 degrees C for genotype 1b (n = 63), 91.08 +/- 0.49 degrees C for genotype 2a (n = 33), and 91.77 +/- 0.28 degrees C for genotype 2b (n = 18). The melting points for genotypes 1b, 2a, and 2b differed by approximately 1 degree C in each other. The genotype was determined for all samples using Okamoto's method and Light cycler system, and both systems produced absolutely identical results for all the samples studied. Sixty-three of 114 were genotype 1b, 33 samples were genotype 2a, and 18 were genotype 2b. This melting curve analysis is a rapid and convenient screening test for differentiation of HCV genotypes 1 and 2.

Benzothiazoles↗
PubMed2004

[Significance of the cardiovascular function tests in patients with collagen diseases, especially for SSc (systemic scleroderma)].

The purpose of this study is to evaluate the cardiovascular function in patients with incomplete type of SSc (SSSD; Scleroderma Sjögren syndrome associated Spectrum Disorders), SSc (Systemic Scleroderma) and SLE (Systemic Lupus Erythematosus) by using ECG and digital plethysmograph. We also preformed ambulatory ECG monitoring for cases of SSSD and SSc with QT interval prolongation. 1) In ECG findings, ischemic myocardial damage, left ventricular hypertrophy or QT interval prolongation was observed in 33% cases of SSSD and 32% cases of SSc, respectively. In addition, parasympathetic disorders were observed in approximately 20% cases of SSSD, SSc and SLE. 2) Digital plethysmogram findings suggested that the peripheral vascular damage was present in both cases of SSSD and SSc, and its severity was lower in SSSD than SSc. The incidence of abnormal cardiovascular function tests in SSSD was relatively less than that in SSc. The cardiovascular function tests are useful to find cardiovascular abnormalities in these collagen diseases.

Adult↗
PubMed2004

[Clinical significance and problems in HCV measurement--comparison of CLEIA method with PCR method].

Infection of a hepatitis C virus (HCV) is confirmed by the presence of HCV antibody or HCV-RNA. Recently, a highly sensitive method to examine HCV-core antigen has been developed. In this study, to evaluate the clinical significance of HCV-core antigen determination, we examined serum HCV infection markers, HCV-core antigen, HCV-RNA (AMPLICOR) and HCV-antibody (third generation) concentrations. We determined 225 serum samples, and three patients receiving the treatment with interferon. In 102 HCV-RNA positive samples, significant correlation was observed between HCV-RNA and HCV-core antigen (r=0.734, p<0.0001). However, three out of 102 (2.9%) cases were included within the negative range of HCV-core antigen (20 fmol/l). The HCV-core antigen value in three patients receiving the treatment with interferon paralleled with the amount of HCV-RNA. The determination of HCV-core antigen by CLEIA is a useful and time-saving method, but an attention should be paid to the presence of false-negative cases.

Biomarkers↗
PubMed2003

Lack of interleukin-1beta decreases the severity of atherosclerosis in ApoE-deficient mice.

OBJECTIVE: Atherosclerosis is considered to be a chronic inflammatory disease and many cytokines participate in the development of atherosclerosis. We focused on the role of interleukin-1beta (IL-1beta), one of the proinflammatory cytokines secreted by monocytes/macrophages, in the progression of atherosclerosis. METHODS AND RESULTS: We generated mice lacking both apoE and IL-1beta. The sizes of atherosclerotic lesions at the aortic sinus in apoE-/-/IL-1beta-/-mice at 12 and 24 weeks of age showed a significant decrease of approximately 30% compared with apoE-/-/IL-1beta+/+ mice, and the percentage of the atherosclerotic area to total area of apoE-/-/IL-1beta-/- at 24 weeks of age also showed a significant decrease of about 30% compared with apoE-/-/IL-1beta+/+. The mRNA levels of vascular cell adhesion molecule (VCAM)-1 and monocyte chemotactic protein-1 in the apoE-/-/IL-1beta-/- aorta were significantly reduced compared with the apoE-/-/IL-1beta+/+. Furthermore, VCAM-1 was also reduced at the protein level in apoE-/-/IL-1beta-/- aorta compared with apoE-/-/IL-1beta+/+. CONCLUSIONS: The lack of IL-1beta decreases the severity of atherosclerosis in apoE deficient mice, possibly through increased expressions of VCAM-1 and monocyte chemotactic protein-1 in the aorta.

Animals↗
PubMed2003

Tumor necrosis factor-alpha from bone marrow-derived cells is not essential for the expression of adhesion molecules in lipopolysaccharide-induced nasal inflammation.

Both the role and source of tumor necrosis factor (TNF-alpha) in lipopolysaccharide (LPS)-induced nasal inflammation were investigated using TNF-alpha gene deficient (TNF-alpha -/-) mice and chimeric mice that are TNF-alpha gene deficient only in bone marrow-derived cells. In the present study, intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA expression levels in the nasal mucosa were significantly decreased following intranasal instillation of LPS in TNF-alpha gene deficient mice compared to those in wild type mice. In contrast, ICAM-1 and VCAM-1 mRNA expressions were not significantly decreased although TNF-alpha mRNA expression was dramatically decreased in TNF-alpha gene deficient bone marrow-transplanted-chimeric (TNF-alpha -/--->+/+) mice compared to those in wild type bone marrow-transplanted-control (TNF-alpha +/+-->+/+) mice. These results indicate that the elevation of TNF-alpha mRNA in the nasal mucosa is mainly originated from bone marrow-derived cells. However, even low expression of TNF-alpha at local inflammation sites is sufficient to induce the expression of adhesion molecules in acute LPS-induced experimental rhinitis.

Animals↗
PubMed2003

The mechanism of interferon-gamma induced anti Toxoplasma gondii by indoleamine 2,3-dioxygenase and/or inducible nitric oxide synthase vary among tissues.

L-Tryptophan degradation by indoleamine 2,3-dioxygenase (IDO) induction and reactive nitrogen intermediates produced by inducible nitric oxide synthase (iNOS) induction are important factors for IFN-gamma-induced anti-toxoplasma activities. In the present study, the effects of acute Toxoplasma gondii (T. gondii) infection on IDO and iNOS were investigated using wild-type (WT) and IFN-gamma gene-deficient (IFN-gamma KO) mice. In the WT C57BL/6J mice, enzyme activities and mRNA levels of IDO in both lung and brain were markedly increased, and lung L-tryptophan concentrations were dramatically decreased following infection. In contrast, these metabolic changes did not occur in infected IFN-gamma KO mice. The level of iNOS induction in the infected IFN-gamma KO mice was high in lung and low in brain compared to that in infected WT mice. The extent of increased mRNA expression of T. gondii surface antigen gene 2 (SAG2) in lung and brain induced by infection was significantly enhanced in the IFN-gamma KO mice compared to that in WT mice. Treatment with N-nitro-L-arginine methyl ester, an iNOS inhibitor, increased the levels of SAG2 mRNA in brain, but not in lung following infection. This in vivo study provides evidence that L-tryptophan depletion caused by T. gondii is directly mediated by IFN-gamma in the lung, where iNOS is not induced by IFN-gamma. This study suggests that there is an anti-toxoplasma mechanism of cross-regulation between iNOS and IDO and that the expression of main anti-parasite effector mechanisms of iNOS and/or IDO may vary among tissues.

Animals↗
PubMed2003

Role of Valpha 14 NKT cells in the development of impaired liver regeneration in vivo.

Although we have previously demonstrated that IL-12 stimulation increases the number of hepatic natural killer (NK) T (NKT) cells and enhances liver injury during the early phase of liver regeneration, the role of NKT cells has remained unknown. We therefore evaluated the influence of NKT cells activated by IL-12 or by alpha-galactosylceramide (alpha-GalCer) on murine liver regeneration using Valpha 14 NKT knockout (Jalpha 281(-/-)) mice. Levels of serum alanine aminotransferase (sALT) 24 hours after partial hepatectomy were enhanced in Jalpha 281(+/+) but not in Jalpha 281(-/-) mice by both procedures. Hepatic NKT cells expressed considerably more interferon (IFN) gamma and tumor necrosis factor alpha (TNF-alpha) messenger RNA (mRNA) after stimulation with both factors in Jalpha 281(+/+) mice. Either anti-IFN-gamma or TNF-alpha antibody inhibited the enhancement of liver injury. Furthermore, recombinant TNF-alpha injection similarly caused injury in hepatectomized livers of both Jalpha 281(+/+) and Jalpha 281(-/-) mice; indeed, adoptively transferred TNF-alpha(+/+) NKT cells enhanced liver injury after hepatectomy in TNF-alpha knockout mice. TNF receptor expressions on hepatocytes increased and peaked 24 hours after partial hepatectomy. In conclusion, simultaneous TNF-alpha synthesis and high levels of TNF receptor expression on hepatocytes cause severe liver damage by activated NKT cells during liver regeneration.

Animals↗
PubMed2003

TNF-alpha contributes to the development of allergic rhinitis in mice.

BACKGROUND: Allergic rhinitis is an inflammation involving T(H)2-type cytokine production, with pathologic eosinophil infiltration in the nasal mucosa. Although TNF-alpha is thought to be a pro-inflammatory cytokine, the relationship between TNF-alpha and allergic rhinitis has not been clarified. OBJECTIVES: The role of TNF-alpha in a murine model of ovalbumin (OVA)-sensitized allergic rhinitis was investigated by using mice deficient in the gene encoding TNF-alpha (TNF-alpha(-/-) mice). METHODS: Both wild-type (TNF-alpha(+/+)) and TNF-alpha(-/-) mice were sensitized with OVA by means of intraperitoneal injection. They were then challenged with intranasal OVA, and various allergic responses were assessed. RESULTS: The production of OVA-specific IgE in the serum (P <.05) and the frequency of sneezes (P <.05) and nasal rubs (P <.05) decreased significantly in TNF-alpha(-/-) mice after OVA sensitization compared with that in TNF-alpha(+/+) mice (P <.05). The mRNA expression of IL-4, IL-10, and eotaxin in nasal mucosa in TNF-alpha(-/-) mice was also significantly suppressed compared with that in TNF-alpha(+/+) mice after OVA sensitization (P <.05). Furthermore, the expression of both endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 mRNA in the nasal mucosa was significantly suppressed (P <.05), although intercellular adhesion molecule 1 mRNA expression did not decrease significantly in TNF-alpha(-/-) mice compared with that in TNF-alpha(+/+) mice after OVA sensitization. In addition, the effect of TNF-alpha on endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 expression by means of Western blot analysis was compatible with the mRNA results. Pathologically, eosinophil infiltration in nasal mucosa was significantly restricted in TNF-alpha(-/-) mice compared with in TNF-alpha(+/+) mice after OVA sensitization (P <.05). CONCLUSION: TNF-alpha is necessary for antigen-specific IgE production and for the induction of T(H)2-type cytokines and chemokines. Furthermore, TNF-alpha might be important for the expression of adhesion molecules to recruit eosinophils to the allergic inflammatory site. We conclude that the lack of TNF-alpha inhibited the development of allergic rhinitis.

Animals↗
PubMed2003

Lack of tumor necrosis factor alpha induces impaired proliferation of hepatitis B virus-specific cytotoxic T lymphocytes.

Recent studies have shown that tumor necrosis factor alpha (TNF-alpha) plays critical roles in not only viral clearance but also lymphoid tissue development and stem cell differentiation. In this study, we attempted to induce hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) by immunization of TNF-alpha knockout (TNF-alpha(-/-)) mice with HBsAg-encoding plasmid DNA. An immunization with the HBV plasmid failed to induce CTL responses in TNF-alpha(-/-) mice, although CTLs were readily induced in wild-type mice by the same protocol. Weak CTL responses were produced in TNF-alpha(-/-) mice after two sessions of immunization with the HBV plasmid; however, TNF-alpha was required to maintain the responses of these CTL lines to in vitro stimulation and, even then, the responses were lost after 3 weeks. Interestingly, a limiting dilution of a CTL line showed that HBV-specific CTL clones with high specific cytotoxicity were present in TNF-alpha(-/-) mice, but these clones again failed to proliferate for more than 3 weeks. Furthermore, since exogenously added TNF-alpha enhanced the proliferation of a TNF-alpha(-/-) clone but suppressed that of a TNF-alpha(+/+) clone in vitro, TNF-alpha also has a direct effect on the proliferation of CTLs. In conclusion, TNF-alpha is essential rather than important for the proliferation of HBV-specific CTLs both in vivo and in vitro and this effect is not only due to the activation of dendritic cells but is also induced by the direct effect on CTLs.

Animals↗