Biomedical subjects

Yasuo Watanabe

Publications and source records attributed to Yasuo Watanabe.

65 records · Page 4Linked to original sources

PubMed2002

Phosphorylation of neuronal nitric oxide synthase at Ser847 by CaM-KII in the hippocampus of rat brain after transient forebrain ischemia.

The authors previously demonstrated that Ca2+/calmodulin (CaM)-dependent protein kinase IIalpha (CaM-KIIalpha) can phosphorylate neuronal nitric oxide synthase (nNOS) at Ser847 and attenuate NOS activity in neuronal cells. In the present study, they established that forebrain ischemia causes an increase in the phosphorylation of nNOS at Ser847 in the hippocampus. This nNOS phosphorylation appeared to be catalyzed by CaM-KII: (1) it correlated with the autophosphorylation of CaM-KIIalpha; (2) it was blocked by the CaM-KII inhibitor, KN-93; and (3) nNOS and CaM-KIIalpha were found to coexist in the hippocampus. Examination of the spatial relation between nNOS and CaM-KIIalpha in the brain revealed coexistence in the hippocampus but not in the cortex during reperfusion, with a concomitant increase in autophosphorylation of CaM-KIIalpha. The phosphorylation of nNOS at Ser847 probably takes place in nonpyramidal hippocampal neurons, which increased after 30 minutes of reperfusion in the hippocampus, whereas no significant increase was detected in the cortex. An intraventricular injection of KN-93 significantly decreased the phosphorylation of nNOS in the hippocampus. These results point to CaM-KII as a protein kinase, which by its colocalization may attenuate the activity of nNOS through its Ser847 phosphorylation, and may thus contribute to promotion of tolerance to postischemic damage in hippocampal neurons.

Animals↗

PubMed2002

Evaluation of T-3811ME (BMS-284756), a new des-F(6)-quinolone, for treatment of meningitis caused by penicillin-resistant Streptococcus pneumoniae in rabbits.

T-3811ME (BMS-284756) is a new des-F(6)-quinolone with high levels of activity against gram-positive bacteria, including penicillin-resistant Streptococcus pneumoniae (PRSP) strains. T-3811, the free base of T-3811ME, exhibited potent activity against 28 clinical strains of PRSP isolated clinically (MIC at which 90% of the isolates tested are inhibited, 0.0625 microg/ml). After the intravenous dosing of T-3811ME (20 mg/kg of body weight as T-3811) in rabbits with meningitis caused by PRSP, the area under the concentration-time curve (AUC) of T-3811 in cerebrospinal fluid (CSF) was 5.79 microg. h/ml and was 4.5-fold higher than that of T-3811in the CSF of rabbits without meningitis. In addition, the AUC/MIC for T-3811ME (20 mg/kg as T-3811) in CSF was 185, which was 4.3-fold higher than that for ceftriaxone (administered intravenously at 100 mg/kg). After the administration of any dose of T-3811ME (5, 10, and 20 mg/kg as T-3811), the viable cell counts in CSF decreased in a dose-dependent manner. In particular, after dosing of 20 mg/kg (as T-3811), the viable cell counts in CSF were significantly less than those in the nontreated group (P < 0.01). By histopathological evaluation, 6 h after the administration of T-3811ME (20 mg/kg as T-3811), the thickening of the cerebral meninx and the infiltration of neutrophils into the cerebral meninx were less severe in the treated group than in the nontreated group. T-3811ME (BMS-284756) may be expected to be evaluated for the management of meningitis caused by highly penicillin-resistant pneumococci.

Animals↗

PubMed2002

Antimutagenic effect of amino acids on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG).

The antimutagenic activity of protein-constituting amino acids except histidine on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in vitro using Salmonella typhinurium TA-100 as an indicator bacterium (Ames test), and concentrations (IC50) of amino acids that inhibit 50% of the mutagenecity were measured. Cysteine was found to be most active and glycine, tryptophan, lysine, and arginine were strong antimutagenic amino acids. Other amino acids showed moderate or weak antimutagenic activities, depending on the amino acids. The results indicate that amino acids play a substantial role in chemoprevention of N-nitroso amine-induced mutagenicity.

Amino Acids↗

PubMed2002

Muscle distribution of antimicrobial agents after a single intravenous administration to rats.

The purpose of this study was to evaluate the distribution of three fluoroquinolones (pazufloxacin, ciprofloxacin and ofloxacin) and a beta-lactam, ceftazidime in the tissue interstitial and intracellular spaces after a single intravenous administration to rats based on muscle microdialysis. The unbound concentration in the tissue interstitial fluid (C(isf,u)) after administration was estimated from the concentration in the dialysate by muscle microdialysis, the in vitro permeability rate constant, and the previously reported effective dialysis coefficient. The C(isf,u)s of pazufloxacin, ciprofloxacin, ofloxacin and ceftazidime in the muscle were close to their unbound concentrations in the venous plasma. These results were consistent with ones previously obtained at steady state. Based on these results, the total concentration in the tissue interstitial fluid (C(isf)) was calculated from the ratio of plasma protein binding, the plasma concentration, and previously reported interstitial-to-plasma albumin ratio in muscle of rats. The calculated C(isf) was compared with the muscle concentration (C(m)) obtained using the homogenized tissue. The C(isf) of ceftazidime was higher than the C(m). The C(isf) of pazufloxacin was found to be almost equal to its C(m). The C(isf)s of ciprofloxacin and ofloxacin were lower than their C(m)s with the exception of the values at 5 min after administration. These results indicate that ceftazidime is mainly distributed in the interstitial space of the muscle, that pazufloxacin is distributed equally in both the interstitial space and the tissue cells, and that ciprofloxacin and ofloxacin are mainly distributed in the tissue cells rather than the interstitial space.

Journal Article↗

PubMed2002

Survivin expression and its correlation with cell proliferation and prognosis in epithelial ovarian tumors.

Survivin is a new member of the inhibitors of apoptosis proteins (IAP) family, selectively overexpressed in common human cancers but not in normal adult tissues, and associated with aggressiveness of the disease and unfavorable outcomes. Recent study also found that survivin expression is associated with cell proliferation. In order to gain insight into the role of survivin in ovarian tumors, we investigated the expression of survivin in a group of epithelial ovarian tumors, and examined the relationship of its expression with cell proliferation and clinical outcome. Immunohistochemical analysis was performed in 103 cases of epithelial ovarian tumors. Twenty-six of the 103 cases were evaluated by Western blot analysis. The results showed that survivin overexpression was detected in 21.2% (7 of 33) of benign tumors, 47.8% (11 of 23) of borderline tumors, and 51.1% (24 of 47) of ovarian carcinomas. The positive ratio was significantly higher in malignant or borderline tumors than in benign tumors, and the overexpression of survivin was significantly correlated with the size of residual disease. A positive correlation between survivin expression and proliferative activity of tumor cell measured by PCNA index was found. Kaplan-Meier analysis demonstrated that the patients with survivin overexpression have a short overall survival. These findings suggest that survivin overexpression may play a pivotal role in the progression of ovarian tumors and may provide an important prognostic implication for epithelial ovarian carcinomas.

Adenocarcinoma, Clear Cell↗

PubMed1999

Two putative MAP kinase genes, ZrHOG1 and ZrHOG2, cloned from the salt-tolerant yeast Zygosaccharomyces rouxii are functionally homologous to the Saccharomyces cerevisiae HOG1 gene.

The salt-tolerant yeast Zygosaccharomyces rouxii can adjust its osmotic balance when responding to osmotic shock by accumulating glycerol as the compatible osmolyte. However, the mechanism of glycerol production in Z. rouxii cells and its genetic regulation remain to be elucidated. Two putative mitogen-activated protein (MAP) kinase genes, ZrHOG1 and ZrHOG2, were cloned from Z. rouxii by their homology with HOG1 from Saccharomyces cerevisiae. The deduced amino acid sequences of ZrHog1p and ZrHog2p indicated close homology to that of Hog1p and contained a TGY motif for phosphorylation by MAP kinase kinase. When ZrHOG1 or ZrHOG2 was expressed in an S. cerevisiae hog1delta null mutant, the salt tolerance and osmotic tolerance characteristics of wild-type S. cerevisiae were restored. In addition, the aberrant cell morphology and low glycerol content of the hog1delta null mutant were corrected, indicating that ZrHog1p and ZrHog2p have functions similar to Hog1p. While the transcription of the glycerol-3-phosphate dehydrogenase gene (GPD1) of the ZrHOG1-harbouring S. cerevisiae mutant was similar to that of wild-type S. cerevisiae, the ZrHOG2-harbouring strain showed prolonged GPD1 transcription. Both Zrhog1delta and Zrhog2delta Z. rouxii null mutants showed a decrease in salt tolerance compared to the wild-type strain. The present study suggested the presence of a high-osmolarity glycerol response (HOG) pathway in Z. rouxii similar to that elucidated in S. cerevisiae. Two putative MAP kinase genes in Z. rouxii appeared to be significant in either osmotic regulation or ion homeostasis.

Amino Acid Sequence↗

PubMedDate not supplied

Aberrant expression of cyclin A in laryngeal squamous cell carcinoma.

The expression of cyclin A protein was retrospectively investigated in 102 patients with human laryngeal squamous cell carcinoma (LSCC) by using immunohistochemistry. Out of 102 tumors, 41 (40.2%) exhibited positive-staining in cancer cells with this antibody. No association between cyclin A overexpression and the patients' clinicopathological parameters was found. However, cyclin A overexpression was significantly associated with CDK2 and PCNA expression (p = 0.01 and p = 0.001, respectively). Kaplan-Meier analysis showed that patients with overexpression of cyclin A were associated with poor disease-free survival (p = 0.046), but it was not associated with overall survival (p = 0.106). Additionally, patients with both lymph node metastasis and cyclin A overexpression were significantly associated with worse disease-free survival (p < 0.0001). The multivariate analysis showed that tumor size, lymph node metastasis and cyclin A overexpression are significantly independent prognostic factors of disease-free survival. These findings suggest that cyclin A overexpression is associated with recurrence of LSCC.

Adult↗

PubMedDate not supplied

Survivin expression in laryngeal squamous cell carcinomas and its prognostic implications.

We examined the expression of survivin using immunohistochemistry in 102 cases of laryngeal squamous cell carcinoma (LSCC). Overall, 65.7% (67 out of 102) of tumors were positive for survivin expression and significantly associated with tumor site, poor differentiation, tumor size, lymph node metastasis and advanced stage. Kaplan-Meier analysis showed that survivin expression was significantly associated with shorter disease-free and overall survival respectively. When survivin expression and clinical stage were combined, patients with both survivin-positive and advanced stage (III, IV) revealed poorer disease-free and overall survival when compared with the other cases (p = 0.0002 and p = 0.0002, respectively). Additionally, in early stage (I, II) cases, survivin expression also showed a significant prognostic trend for disease-free and overall survival (p = 0.0727 and p = 0.0701, respectively). By the multivariate analysis, tumor size, lymph node metastasis and survivin expression were independent prognostic factors both in disease-free and overall survival. These findings indicate that survivin expression is associated with unfavorable clinicopathological parameters and represents an independent marker for prognosis of LSCC.

Adult↗

PubMedDate not supplied

Expression of p57kip2 and its clinical relevance in epithelial ovarian tumors.

BACKGROUND: The aim of this study was to elucidate the expression of p57kip2 in a series of benign, borderline and malignant ovarian tumors, to evaluate its relationship with other G1 regulators of the cell cycle and to determine whether p57kip2 expression is associated with progression and prognosis of epithelial ovarian tumors. MATERIALS AND METHODS: Immunohistochemical analysis was performed in 103 cases of epithelial ovarian tumors. Twenty-six of the 103 cases were evaluated by Western blot analysis. RESULTS: The study demonstrated that high p57kip2 expression was detected in 63.6% (21 out of 33) of benign tumors, 52.2% (12 out of 23) of borderline tumors and 40.4% (19 out of 47) of ovarian carcinomas. The positive ratio of p57kip2 expression was decreased from benign to borderline to malignant tumors, whilst statistical significance was observed between benign and malignant tumors. Low p57kip2 expression was significantly associated with high tumor grades, advanced clinical stages and cyclin E overexpression. Kaplan-Meier analysis demonstrated that the patients with low p57kip2 expression had a short overall survival. When the combined phenotype of p57kip2 and p27kip1 was analyzed, the patients with both p57kip2 and p27kip1 low expression had a lower overall survival rate. CONCLUSION: These findings suggest that decreased p57kip2 expression may play a pivotal role in the progression of ovarian tumors and provide an important prognostic implication for epithelial ovarian carcinomas.

Blotting, Western↗

PubMedDate not supplied

S-phase kinase-associated protein 2 expression in laryngeal squamous cell carcinomas and its prognostic implications.

The F-box protein S-phase kinase-associated protein 2 (Skp2) positively regulates the G1-S transition by controlling the stability of several G1 regulators, such as the cell cycle inhibitor p27kip1. However, the clinical significance of Skp2 in patients with laryngeal squamous cell carcinoma (LSCC) remains unknown. In this study, a potential distribution of Skp2 in LSCC and its clinical implications was investigated by an immunohistochemical study. Overall, Skp2 overexpression was observed in 36.7% (37 of 102) patients and was significantly associated with lymph node metastasis (p=0.002) and was inversely associated with p27kip1 expression (p=0.026). Survival analysis using the Kaplan-Meier method showed that Skp2 overexpression was significantly associated with shorter disease-free and overall survival (p=0.0051 and p=0.0002, respectively). When Skp2 expression and p27kip1 expression were combined, patients with both Skp2 overexpression and reduced expression of p27kip1 revealed poorest disease-free and overall survival as compared to the other cases (p=0.0017 and p<0.0001, respectively). Additionally, in early stage (I, II) cases, Skp2 expression was also revealed to possess a significant prognostic factor in overall survival (p=0.0234), but not in disease-free survival (p=0.2055). By multivariate analysis using the Cox proportional hazards model, tumor grade, tumor size, clinical stage and Skp2 expression were independent prognostic factors both in disease-free and overall survival. These findings indicated that Skp2 expression was closely associated with tumor progression and represented an independent marker for prognosis of LSCC.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Growth inhibitory effect of D-allose on human ovarian carcinoma cells in vitro.

BACKGROUND: D-allose is a rare sugar found in nature and, because of its very limited amount and of the high cost associated with its synthesis, its physiological functions remain virtually unknown. The aim of the current study was to investigate the effect of D-allose on the proliferation of human ovarian carcinoma cells in vitro. MATERIALS AND METHODS: Human ovarian carcinoma cells (OVCAR-3 cell line) were exposed to rare sugars including D-allose, D-altrose, D-psicose and D-talitol. Cell growth was evaluated by MTT assay. Cell cycle analysis was carried out by flow cytometric assay. The expression of cell cycle regulatory proteins was determined by Western blot analysis. TUNEL assay was employed for the detection of apoptotic cells. RESULTS: D-allose had a significant inhibitory effect on ovarian cancer cell proliferation in a dose-dependent manner, and caused a moderate G2/M arrest in the cell cycle, up-regulation of Cdk inhibitors p21 and p27 levels, and the induction of apoptosis in OVCAR-3 cells. CONCLUSION: Our results show, for the first time, that D-allose inhibits the growth of ovarian carcinoma cells in vitro. Although the exact mechanisms remain unclear, these findings suggest that D-allose possesses a novel inhibitory property on ovarian carcinoma cell proliferation, and may represent a new class of compounds with possible therapeutic potential.

Adenocarcinoma↗