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Biomedical subjects

M Tokuda

Publications and source records attributed to M Tokuda.

At least 37 records · Page 2Linked to original sources
PubMed2001

Growth hormone prevents Fas-induced apoptosis in lymphocytes through modulation of Bcl-2 and caspase-3.

OBJECTIVE: Growth hormone (GH) has been reported to have a potent effect on the immune system. However, the detailed mechanism of the effect of GH on the immune system has not yet been clarified. This study was designed to investigate the nature of this mechanism. METHODS: In the present study, we investigated the effects of GH on the susceptibility of both human CEM/C7 lymphocytes and human IM-9 lymphocytes to Fas-induced apoptosis. RESULTS: Both cell lines expressed GH receptor mRNA. GH rescued Fas-induced suppression of [(3)H]-thymidine incorporation into each cell line. GH prevented Fas-induced apoptosis in each cell line without changing Fas antigen expression. We next investigated the mechanisms of the prevention of Fas-induced apoptosis, by focusing on intracellular molecules related to the apoptotic signal. Bcl-2 expression was increased by GH treatment in both CEM/C7 and IM-9 lymphocytes. GH also downregulated caspase-3 expression and inhibited activation of caspase-3 in both cell lines. CONCLUSION: These findings suggest that GH regulates the human immune system through inhibition of Fas-induced apoptosis in activated T and B lymphocytes.

Antibodies, Monoclonal↗
PubMed2001

Cyclin-dependent kinase inhibitor p27 is related to cell proliferation and prognosis in laryngeal squamous cell carcinomas.

An immunohistochemical study of both p27 and proliferating cell nuclear antigen (PCNA) was performed on 102 cases of laryngeal squamous cell carcinomas (LSCCs), and large variations in p27 expression were found among the tumours. Reduced expression of p27 was revealed in 54 (52.9 per cent) cases and correlated with tumour size, lymph node metastasis, and clinical stage, but did not correlate with age, sex, tumour site, or tumour grade. A significant positive correlation was found between the percentage of loss of p27 expression and the PCNA index (r = 0.844, p < 0.0001). Reduced expression of p27 was significantly correlated with both reducing disease-free and overall survival by univariate analysis. By multivariate analysis, reduced expression of p27, tumour grade, tumour size, lymph node metastasis as well as clinical stage were independent prognostic factors for overall survival of LSCCs. These findings indicate that reduced expression of p27 may be correlated with the malignant biological behaviour of LSCCs.

Aged↗
PubMed2001

Jab1 expression is associated with inverse expression of p27(kip1) and poor prognosis in epithelial ovarian tumors.

PURPOSE: Jab1 (Jun activation domain-binding protein 1) has been described as a coactivtor of AP1 transcription factor, and is a subunit of a large protein complex (called the COP9 signalosome). Recent study (K. Tomoda et al., Nature (Lond.), 398: 160-165, 1999) found that Jab1 protein can cause breakdown of p27(kip1) protein in mammalian cells. To investigate whether Jab1 expression is correlated with p27(kip1) protein levels as well as how it might be clinically relevant, we evaluated the expression of Jab1 in a group of epithelial ovarian tumors. EXPERIMENTAL DESIGN: Immunohistochemical analysis was performed in 80 cases of ovarian tumors (33 benign ovarian tumors and 47 ovarian carcinomas). Twenty-six of the 80 cases were evaluated by Western blot analysis. RESULTS: Jab1 overexpression was detected in 68.1% (32 of 47) of malignant tumors and 33.3% (11 of 33) of benign tumors. The positive ratio of Jab1 was increased from benign to malignant ovarian tumors (P = 0.002). A negative correlation between Jab1 and p27(kip1) expression was found in both benign (P = 0.003) and malignant (P = 0.002) ovarian tumors. No significant correlation was observed between Jab1 overexpression and clinicopathological parameters. Kaplan-Meier survival analysis showed that Jab1 overexpression was significantly associated with poor prognosis of patients (P = 0.049). CONCLUSIONS: Jab1 expression is inversely correlated with p27(kip1) expression levels, and Jab1, as a negative regulator of p27(kip1), may be associated with the progression and prognosis of epithelial ovarian tumors.

COP9 Signalosome Complex↗
PubMed2001

Non-specific interstitial pneumonia and Chlamydia pneumoniae infection.

Recently, the clinical features of non-specific interstitial pneumonia (NSIP) have been described. We hypothesize that recurrent infection caused by Chlamydia pneumoniae may play a role in the pathogenesis of NSIP. To prove this, we quantified serum IgA and IgG antibodies against C. pneumoniae using the enzyme linked-immunosorbent assay kit. The study included 15 patients diagnosed with NSIP, 20 patients with chronic obstructive pulmonary diseases (COPD) as disease group, and 27 control subjects. IgA antibody against C. pneumoniae was positive in 12 of 15 patients with NSIP, in 16 of 20 patients with COPD, and in 14 of 27 control subjects. IgG antibody against C. pneumoniae was positive in 14 of 15 patients with NSIP, in 17 of 20 patients with COPD, and in 16 of 27 control subjects. If the cut off value (mean +/- 2SD, index more than 3.0) was introduced, IgA and/or IgG antibodies against C. pneumoniae were positive in 8 of 15 patients with NSIP (53.3%), in 9 of 20 patients with COPD (45%), and in 2 of 27 control subjects (7.4%). These results suggest that infection of C. pneumoniae might play a role in the pathogenesis of NSIP.

Adult↗
PubMed2000

Benzolactams. 4. Reaction of 3',4'- or 4',5'-dialkoxy-substituted 1-(2'-Bromobenzyl)-2-ethoxycarbonyl-1,2,3,4-tetrahydroisoquinolines with alkyllithium. 1,2 and 1,4 additions of alkyllithium to benzolactams.

Treatment of 1-(2'-bromo-3',4'-dialkoxybenzyl)-1,2,3, 4-tetrahydroisoquinoline carbamates, 1a,c, with excess alkyllithium gave 8-oxoberbines, 2a,c, which were successively attacked in situ with another molecule of alkyllithium to give 1,2 and/or 1,4 addition products. A primary alkyllithium, such as MeLi or BuLi, gave a 1,2 addition product, 8-methyleneberbine 9a or 8-butylideneberbine 3a. t-BuLi preferred 1,4 addition, followed by elimination of the alkoxy group, to give 9-tert-butyl-8-oxoberbine 6a or 7c. s-BuLi gave a mixture of 1,2 and 1,4 addition products, 1-[2'-(2' '-methylbutyryl)benzyl]-1,2,3,4-tetrahydroisoquinoline 4a and 9-s-butyl-8-oxoberbine 5a. Similar treatments of carbamate 1b having no alkoxy group at its 3' position gave 1,2 addition products, 8-butylideneberbine 3b, 1-[2'-(2' '-methylbutyryl)benzyl]-1,2,3, 4-tetrahydroisoquinoline 4b, and 1-(2'-pivaloylbenzyl)-1,2,3, 4-tetrahydroisoquinoline 6b, in all cases. Reactions of 1a with s-BuMgCl and isoPrMgCl also gave the 1,4 adduct, 5a, and its 9-isoPr analogue, 12a. Treatment of 9a with excess NaBH(4) in AcOH gave (+/-)-coralydine (10b).

Antineoplastic Agents↗
PubMed2000

Enhanced expression and activation of Ca(2+)/calmodulin-dependent protein kinase IV in hepatocellular carcinoma.

BACKGROUND: Ca(2+)/calmodulin-dependent protein kinase IV (CaM-kinase IV) is a multifunctional protein kinase that is expressed abundantly in the central nervous system and, to a lesser degree, in nonneuronal tissues such as the liver. In the current study, the authors demonstrated the expression of CaM-kinase IV in hepatocytes from hepatocellular carcinoma (HCC) in both humans and rats. METHODS: Immunoblotting and immunohistochemical analysis were performed to confirm the expression of CaM-kinase IV and CaM-kinase kinase in HCC occurring in both humans and rats. The kinase activity of CaM-kinase IV in the lysate of each of these liver supernatant fluids was measured using a specific substrate (peptide gamma) for this enzyme before and after phosphorylation by exogenously added CaM-kinase kinase. RESULTS: Marked positive staining of HCC hepatocytes was found and the subcellular staining pattern mainly was cytosolic. One immunoreactive band with a molecular weight of 64 kilodaltons, which was identical to an isoform of rat cerebellum CaM-kinase IV, was demonstrated by immunoblotting. Ca(2+)/calmodulin-dependent CaM-kinase IV activity was high in HCC and showed almost no difference in activity in specimens with and without CaM-kinase kinase phosphorylation. CONCLUSIONS: CaM-kinase IV was found to be expressed in HCC and might have been involved in the development of HCC. CaM-kinase IV that was expressed in cancerous hepatocytes was phosphorylated mainly by CaM-kinase kinase that also was expressed in tumor cells.

Animals↗
PubMed2000

Expression and subcellular localization of multifunctional calmodulin-dependent protein kinases-I, -II and -IV are altered in rat hippocampal CA1 neurons after induction of long-term potentiation.

Long-term potentiation (LTP) is considered to be associated with an increase in expression as well as activity of Ca(2+)/calmodulin-dependent protein kinases (CaMKs). LTP-induced and control hippocampal slices were studied by immunohistochemical and electronmicroscopic analyses using anti-CaMK-I, -II and -IV antibodies. All three kinases were demonstrated to increase their expression in CA1 neurons. CaMK-I was shown to mainly localize in the cytoplasm of the control and LTP-induced neurons, and a significant increase of immunoreactivity was observed in the latter neurons. A part of CaMK-I was found to translocate to the nuclei of LTP-induced hippocampal CA1 neurons. Direct evidence of the translocation of CaMK-II from cytoplasm to nuclei in LTP was demonstrated by immuno-electronmicroscopy. A significant increase in expression of CaMK-IV in the nuclei was also observed. Our data suggest that all the three CaMKs were actively involved in nuclear Ca(2+)-signaling in LTP.

Animals↗
PubMed2000

Aryl radical cyclizations: one-Pot syntheses of protoberberine and pavine alkaloids.

Treatment of 2-(2'-bromo-beta-phenethyl)isocarbostyrils 7 with AIBN-Bu(3)SnH in boiling benzene gave 8-oxoberbines 3 in good yields. A similar treatment of 2-(2'-bromo-beta-phenethyl)isoquinolinium bromides 6 and their nor- and homoanalogues (10,11) induced 6-, 5-, and 7-exo radical closures in a one-pot manner to give protoberberines 2, dibenzo[b,g]indolizidine 14a and, dibenzo[a, h]-1-azabicyclo[5.4.0]undecane 15a, respectively. A one-pot radical cyclization of 1-(2'-bromobenzyl)isoquinoline methiodide 18a gave a pavine alkaloid, (+/-)-algemonine (19a).

Alkaloids↗
PubMed2000

Depression of long term potentiation in gerbil hippocampus following postischemic hypothermia.

To investigate the mechanism of chronic cell death following postischemic hypothermia, the change of N-methyl-D-aspartate receptor (NMDAR) were examined by immunohistochemistry of NMDAR1 and long-term potentiation (LTP) in the CA1 subfield of the gerbil hippocampus. At 1 week following postischemic hypothermia (32 degrees Cx4 h), all CA1 neurons survived; however, immunoreactivity of NMDAR1 increased in neuronal perikarya whereas decreased in dendrites in the CA1 neurons. The abnormality was still observed in remaining CA1 neurons at 1 month after hypothermia. LTP was also significantly depressed at 1 week after hypothermia. These results suggest that some abnormalities in the glutamate receptor may be caused by ischemia; such abnormality would persist in spite of hypothermia treatment, resulting in the depression of LTP.

Animals↗
PubMed2000

A Facile Route to Indolo

Treatment of 1-(2'-bromobenzyl)-3,4-dihydroisoquinolines 2 in the presence of K(2)CO(3) in boiling DMF efficiently provided a variety of alkoxy-substituted indolo[2,1-a]isoquinolines 3. Application of this cyclization to 7-benzyloxyisoquinoline derivatives, followed by further elaboration of the resultant 2-benzyloxy-5,6-dihydroindolo[2,1-a]isoquinolines 16a,b, led to the formal synthesis of dibenzopyrrocoline alkaloids, (+/-)-cryptaustoline (1a) and (+/-)-cryptowoline (1b).

Journal Article↗
PubMed2000

Aryl radical cyclizations of 1-(2'-bromobenzyl)isoquinolines with AIBN-Bu3SnH: formation of aporphines and indolo

[reaction: see text] Radical cyclization of alkoxy-substituted 1-(2'-bromobenzyl)-3,4-dihydroisoquinolines 1 with AIBN-Bu3SnH gave 6a,7-dehydroaporphines 2 preferentially. A steric repulsion between the respective alkoxy groups at the 7- and 3'-positions gave 5,6-dihydroindolo[2,1-a]isoquinolines 3 in a "disfavored" 5-endo cyclization mode. Radical cyclizations of the related substrates, such as 1-(2'-bromobenzoyl)isoquinolines or 1-(2'-bromo-alpha-hydroxybenzyl)isoquinolines, were also found to give the corresponding oxoaporphines or oxyaporphines.

Journal Article↗
PubMed2000

Inverse expression of Cdk4 and p16 in epithelial ovarian tumors.

OBJECTIVES: The aim of this study was to elucidate the expression and the correlation of two cell cycle regulators, cdk4 and its inhibitor p16, in a series of benign, borderline, and malignant ovarian tumors and to evaluate whether their alterations correlate with clinicopathologial parameters and patients' prognosis in epithelial ovarian carcinomas. METHODS: Immunohistochemical analysis using anti-cdk4 and anti-p16 antibodies was carried out for 103 paraffin sections of ovarian tumors, and Western blot analysis and cdk4 activity assay were performed in 26 fresh ovarian tumor samples. RESULTS: The results of immunohistochemistry showed that 60.61 and 69.70% of benign, 69.57 and 56.52% of borderline, and 74.47 and 40. 43% of malignant tumors expressed cdk4 and p16, respectively, demonstrating increased cdk4 and decreased p16 expression in ovarian carcinomas. A significant inverse relationship between cdk4 and p16 expression was found. The loss of p16 expression was more correlated with G(2) and G(3) tumors in contrast with G(1) tumors. No significant correlation was observed between cdk4 expression and clinicopathological parameters. Neither cdk4 nor p16 expression has significant effects on overall survival by the Kaplan-Meier method. When the combined phenotypes of the two proteins were analyzed, patients with cdk4-positive/p16-negative expression had a reduced overall survival than other phenotypes of cdk4/p16. CONCLUSIONS: These data suggest that inverse expression of cdk4 and p16 may be involved in the development and progression of epithelial ovarian carcinomas. The combined phenotypes of cdk4 and p16 proteins could provide a useful prognostic indicator for patients with epithelial ovarian carcinoma.

Adenocarcinoma↗
PubMed2000

A possible novel src-related tyrosine kinase in cancer cells of LEC rats that develop hepatocellular carcinoma.

BACKGROUNDS/AIMS: Src-related protein tyrosine kinase is known to be related to cell transformation. In this study, we report a possible novel src-related tyrosine kinase of 100 kDa specifically expressed in the nuclei of hepatocytes and/or cancer cells in Long-Evans Cinnamon rats, one of the experimental models of hepatocellular carcinoma. METHODS: Src-related protein tyrosine kinase in hepatocytes of Long-Evans Cinnamon rats was analyzed by using immunohistochemistry and Western blot and in vitro tyrosine kinase assay using a specific antibody (src antibody) against a synthetic peptide corresponding to the conserved autophosphorylation site of src family tyrosine kinases. RESULTS: Src-related protein was found to be expressed in the nuclei of hepatocytes and/or cancer cells in Long-Evans Cinnamon rat liver, exhibiting tyrosine kinase activity, and migrated to the position of 100 kDa. The protein quantity and activity of this 100-kDa src-related protein tyrosine kinase significantly increased with the progress of chronic hepatitis to hepatocellular carcinoma, especially in the tumorous portion of the liver. On the other hand, the 100-kDa src-protein tyrosine kinase was not observed in the nuclei of hepatocytes and/or cancer cells in normal age-matched control Wistar rats. CONCLUSIONS: Since the src-family tyrosine kinases have been observed at a molecular weight of 55 to 62 kDa and located in the hepatocellular membrane and/or cytoplasm, the 100-kDa src-related protein tyrosine kinase observed in the present study may be novel, and closely related to the pre-cancerous and cancerous process in Long-Evans Cinnamon rat liver.

Animals↗
PubMed2000

Presenilin-1 protein specifically expressed in Leydig cells with its expression level increased during rat testis development.

Presenilin-1, mutations of which cause the early-onset of Alzheimer's disease, was shown to be abundantly expressed in the testis as well as the brain. In spite of the high expression level of this protein in the testis, no further analysis has been undertaken. We aimed to study the distribution and developmental changes in presenilin-1 protein, and to provide clues so as to elucidate the role of this protein in the rat testis. To evaluate the specificity of the anti presenilin-1 antibody, rat presenilin-1 protein was expressed in COS-7 cells and the recombinant protein was used for western blot analysis. A positive band of approximately 20 kDa corresponding to the C-terminal fragment of proteolyzed presenilin-1 protein was observed. Using testis and brain tissue samples, a 20 kDa band was detected in both tissues suggesting a similar proteolytic process, but the expression level in the testis was higher than that in the brain. The expression level increased significantly during postnatal testis development. By an immunohistochemical analysis of the rat testis, a strong signal was observed in interstitial cells and further study with cultured TM3 murine Leydig cells revealed an abundant expression of presenilin-1 in Leydig cells. Our study suggests that presenilin-1 expression in Leydig cells may play an important role in Leydig cell function and testis development.

Animals↗
PubMed2000

Combined use of cyclosporine A and methotrexate in refractory polymyositis.

Polymyositis is an inflammatory muscle disease with unknown cause that is characterized by progressive weakness of the proximal muscles. Limited information is available concerning the effectiveness of the combination therapy with cyclosporine A and methotrexate in reducing myositis activity. We describe here a female patient with polymyositis who showed resistance to pulse corticosteroid therapy. Neither the combination of azathioprine (100 mg/day) nor methotrexate (10 mg/week) with corticosteroids decreased the value of creatine phosphokinase. Normalization of the creatine phosphokinase level as well as improvement of muscle strength was obtained only when low-dose cyclosporine A (3 mg/kg/day) was combined with methotrexate.

Antirheumatic Agents↗
PubMed2000

Sequential changes of KL-6 in sera of patients with interstitial pneumonia associated with polymyositis/dermatomyositis.

OBJECTIVE: KL-6 is a mucin-like high molecular weight glycoprotein, which is strongly expressed on type II alveolar pneumocytes and bronchiolar epithelial cells. It has been demonstrated that the KL-6 antigen is a useful marker for estimating the activity of interstitial pneumonia. In this study, it is hypothesised that serum KL-6 is a useful marker to evaluate the activity of interstitial pneumonia associated with polymyositis/dermatomyositis (PM/DM). METHODS: KL-6 was measured in sera in 16 patients diagnosed with PM/DM. Five had non-specific interstitial pneumonia (NSIP), three had diffuse alveolar damage (DAD), and eight had no pulmonary involvement, and 10 were normal non-smokers as a control group. The correlation was also evaluated between the KL-6 level and each clinical course in patients with pulmonary involvement associated with PM/DM. Immunohistochemical analysis using monoclonal anti-KL-6 antibody was also performed. RESULTS: KL-6 concentrations in sera of patients with interstitial pneumonia associated with PM/DM were significantly high compared with those of PM/DM without interstitial pneumonia, and normal non-smokers. KL-6 concentrations in sera in patients with DAD significantly increased compared with those of other groups. KL-6 values in sera changed according to the progression or improvement of interstitial pneumonia. Immunohistochemical study using pulmonary tissues obtained from patients with DAD demonstrated that the hyaline membrane, proliferating type II pneumocytes, bronchial epithelial cells and some endothelial cells in pulmonary veins were stained by antihuman KL-6 antibody. CONCLUSION: These data demonstrate that measurement of serum KL-6 was a useful marker to evaluate the activity of acute interstitial pneumonia associated with PM/DM.

Acute Disease↗
PubMed2000

Circulating cytokeratin 8:anti-cytokeratin 8 antibody immune complexes in sera of patients with pulmonary fibrosis.

BACKGROUND: It has been suggested that the humoral immune system plays a role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD). Although circulating immune complexes in patients' sera have been suggested, none of the antigens have been characterized. OBJECTIVES: The purpose of this study is to characterize the antigen of the immune complexes in patients' sera of pulmonary fibrosis. METHODS: As we previously established that one of the antibodies against A549 cells (lung alveolar type II cells) was anti-cytokeratin 8 (CK8), we confirmed the existence of anti-CK8 antibody in patients' sera by Western immunoblot. In addition, we tried to demonstrate circulating CK8:anti-CK8 immune complexes in patients' sera by Western immunoblot. Furthermore, we established an enzyme-linked immunosorbent assay to quantitate CK8:anti-CK8 immune complexes. RESULTS: In patients with pulmonary fibrosis, anti-CK8 antibodies were clearly demonstrated in sera by Western immunoblot. In addition, circulating CK8:anti-CK8 immune complexes were also clearly demonstrated by Western immunoblot. It was possible to establish ELISA to quantitate CK8:anti-CK8 immune complexes. If the cutoff value, which was determined based on the highest value of normal volunteers, was introduced, high CK8:anti-CK8 antibody complexes were demonstrated in 9 of 31 patients (29.0%) with IPF and PF-CVD. CONCLUSIONS: This is the first study to clarify the antigen of the circulating immune complex in sera of patients with IPF. These results suggest that circulating CK8:anti-CK8 immune complexes may have played a role in the process of lung injury in pulmonary fibrosis.

Aged↗