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Biomedical subjects

H Osada

Publications and source records attributed to H Osada.

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

TU-572, a potent and selective CD45 inhibitor, suppresses IgE-mediated anaphylaxis and murine contact hypersensitivity reactions.

BACKGROUND: CD45, receptor-type protein tyrosine phosphatases (PTPases) are essential components of signaling through both the T cell receptor and the B cell antigen receptor. However, the functional significance of CD45 in the signaling pathway through the high-affinity immunoglobulin (Ig) E receptor has not yet been established. In this study, we demonstrate that the potent CD45 inhibitor negatively regulates IgE-dependent anaphylaxis and contact hypersensitivity reactions. METHOD: We have previously found that TU-572, 2-[(4-methylthiopyridin-2-yl)methylsulfinyl]-5-isopropoxybenzimidazole, had a potent and selective inhibitory effect against PTPase activity of CD45. Using a CD45 inhibitor, we examined in vitro and in vivo IgE-mediated responses. RESULTS: TU-572 potently inhibited histamine release from rat peritoneal mast cells and mouse systemic anaphylaxis reaction using monoclonal anti-dinitrophenyl (DNP) IgE and DNP-BSA. TU-572 also suppressed the immediate-type hypersensitivity response induced by repeated epicutaneous application of trinitrochlorobenzene in BALB/c mice. CONCLUSION: These findings revealed that the PTPase activity of CD45 played a critical role in signal transduction of IgE-mediated anaphylaxis in vitro and in vivo. PTPase inhibitors such as TU-572 are useful in the treatment of allergic diseases.

Anaphylaxis↗
PubMed2001

Inhibition of telomerase activity by fungus metabolites, CRM646-A and thielavin B.

We performed a screening program to identify telomerase inhibitors from our drug source obtained from fungus fermentations, and found that two compounds, CRM646-A and thielavin B, inhibited telomerase activity at doses of 3.2 and 32 microM, respectively. These compounds also inhibited the activity of viral reverse transcriptase at almost the same dose levels which inhibited telomerase activity.

Enzyme Inhibitors↗
PubMed2001

[Method-performance studies of notified analytical method for inabenfide].

Method-performance studies were conducted for the notified revised analytical method of inabenfide in unpolished rice. Six laboratories analyzed unpolished rice spiked with 0.05 microgram/g of inabenfide in replicate. Mean recovery from rice was 85.0%. Repeatability relative standard deviation value was 4.2% and reproducibility relative standard deviation value was 8.1%. The detection limits were 0.002-0.01 microgram/g.

Isonicotinic Acids↗
PubMed2001

[Method-performance studies of notified analytical method for chinomethionat].

Method-performance studies were conducted for the notified revised analytical method of chinomethionat in agricultural products by interlaboratory study. Six laboratories analyzed unpolished rice, cabbage, squash, lettuce and orange spiked with 0.1 microgram/g of chinomethionat in replicate. Mean values of recovery from the 5 crops ranged from 90.2 to 100.5%. Repeatability relative standard deviations ranged from 4.4 to 7.7% and reproducibility relative standard deviations ranged from 10.9 to 17.1%. The detection limits were 0.003-0.012 microgram/g.

Brassica↗
PubMed2001

[Method-performance studies of notified analytical method for clofentezine].

Method-performance studies were conducted for the notified revised analytical method of clofentezine. Clofentezine spiked in azuki beans, apple, orange, banana, grape, tea powder and tea extract at the level of 0.2 microgram/g (2 micrograms/g for tea) was analyzed in replicate in 6 laboratories. Mean values of recovery from 7 crops ranged from 78.4 to 85.2%. Repeatability relative standard deviation values ranged from 2.2 to 4.6% and reproducibility standard deviation values ranged from 4.8 to 10.3%. The detection limits were 0.005-0.01 microgram/g. These results show the notified analytical method has good performance.

Chlorobenzenes↗
PubMed2001

Gene expression of angiogenesis related factors in glioma.

Angiogenesis plays an important role in growth and proliferation of cancer. Various angiogenic and angiostatic factors regulate angiogenesis. In this study, we examined gene expression of the angiopoietin family including angiopoietin 1 (Ang1) and angiopoietin 2 (Ang2) in 39 gliomas and 5 glioma-xenografts by RT-PCR. Ang1 and Ang2 genes were expressed in 54%, and 77% of gliomas, respectively. The expression of Ang1 was significantly correlated with the expression of Ang2. Both Ang1 and Ang2 were shown to be expressed in the glioma cells. Ang2 gene expression was correlated with VEGF gene expression. Angiopoietin molecules may synergistically cooperate in growth and vascularization in glioma.

Angiopoietin-1↗
PubMed2001

Interleukin 10 expression is correlated with thrombospondin expression and decreased vascular involvement in colon cancer.

Interleukin 10 (IL-10) is an immuno-suppressive cytokine produced by T-lymphocytes, and a regulatory molecule for angiogenesis in various cancers. We examined IL-10 gene expression in 53 colon cancer patients who underwent surgical resection. IL-10 gene expression was correlated with TSP1 and TSP2 gene expression (P=0.0049, P=0.0285). Colon cancer with IL-10 gene expression (19/53) showed significantly decreased venous involvement (P=0.0433). The mean vessel counts in the colon cancers with IL-10 gene expression were significantly lower than those without IL-10 gene expression (P<0.001). These results suggested that IL-10 stimulates angiostatic factor gene expression, and results in suppression of venous involvement.

Adenocarcinoma↗
PubMed2001

Isolation, and biological properties of a new cell cycle inhibitor, curvularol, isolated from Curvularia sp. RK97-F166.

A new cell growth inhibitor, curvularol, was isolated from the fermentation broth of Curvularia sp. RK97-F166. Curvularol showed no antibacterial activity, and very weak antifungal activity. However, curvularol inhibited the cell cycle progression of normal rat kidney (NRK) cells in G1 phase at 150 ng/ml. Curvularol induced the morphological reversion of srcts-transformed NRK cells at 100 ng/ml, and inhibited protein synthesis same as cycloheximide.

Animals↗
PubMed2001

A facile and effective screening method for p21WAF1 promoter activators from microbial metabolites.

We have developed a novel p21WAF1 promoter activator screening system based on rapid and facile luciferase activity assay of a model cell system (H1299/tsp53-luc cells), a stable luciferase expression cell line established by transfecting H1299/tsp53 cells with a reporter gene construct pWWP-Luc-BSD. This plasmid was constructed by subcloning the 2.4 kb p21WAF1 promoter and a 2.6 kb of luciferase cDNA fragment activated by the p21WAF1 promoter into a pMAM2-BSD expression vector containing the blasticidin S deaminase gene (BSD). A BSD-resistant clone H1299/tsp53-luc#4, showing the highest response to p53 activation (by temperature shift from 37 degrees C to 32 degrees C) by luciferase production, was used for screening microbial culture broths. Among approximately 1200 screened samples, trichostatin A related compounds and a new compound, lucilactaene, were isolated. This provides an effective and facile screening system for p21WAF1 promoter activators which should be of considerable value in the rapid identification of new anticancer agents.

Antibiotics, Antineoplastic↗
PubMed2001

Significant correlation between interleukin 10 expression and vascularization through angiopoietin/TIE2 networks in non-small cell lung cancer.

The expression of interleukin 10 (IL-10) is correlated with clinical prognosis in non-small cell lung cancer [NSCLC (H. Hatanaka et al., ANN: ONCOL:, 11: 815--819, 2000)]. However, the effects of IL-10 expression on vascularization in NSCLC are not apparent. We examined the gene expression of IL-10/IL-10 receptor and various angiogenic/angioinhibitory factors in 95 NSCLC samples to determine the correlation between IL-10 production and vascularization. Vascular endothelial growth factor, angiopoietin [Ang (Ang-1 and Ang-2)], thrombospondin, brain-specific angiogenesis inhibitor 1, vascular endothelial growth factor receptors (KDR and flt-1), and Ang receptor (TIE2) gene expression were evaluated by reverse transcription-PCR. The cellular localization of these factors and vascularity in the cancer stroma were examined immunohistochemically. Seventy-eight (82.1%) and 93 (97.9%) of these 95 NSCLCs were positive for IL-10 and IL-10 receptor, respectively. Ang-1, Ang-2, and TIE2 gene expression was seen in 76 (97.4%), 73 (93.6%), and 78 (100%) of 78 IL-10-positive NSCLCs, respectively, and was significantly correlated with IL-10 gene expression (P < 0.0088, <0.0008, and 0.0305, respectively; Fisher's exact method). The localizations of Ang-1, Ang-2, and TIE2 were confirmed within tumor cells immunohistochemically. Vascular number and measurement area were significantly higher in the IL-10-positive NSCLCs (33.500 +/- 9.299/microm(2) and 4.742 +/- 1.287%) as compared with IL-10-negative NSCLCs (10.611 +/- 2.839/microm(2) and 0.718 +/- 0.331%; Mann-Whitney U test, P = 0.0039). The IL-10 expression did not show any significant correlation with the expression of other factors. These results suggested that tumor-produced IL-10 promotes stromal vascularization through expression of Ang-1, Ang-2, and TIE2.

Angiogenesis Inhibitors↗
PubMed2001

[Development and evaluation of a QOL questionnaire for elderly subject living in a community].

A comprehensive, basic and simple QOL questionnaire for elderly subjects living in a community was developed, and its validity and reliability were examined. The subjects were 2944 individuals of 65 years or older living in 5 areas of metropolitan Tokyo and in a town of Aichi Prefecture. The QOL questionnaire with 19 questions was developed based on the component of QOL by Lawton and concept of QOL by Koyano. The questionnaire consisted of 6 subscales (daily activity, satisfaction with health, satisfaction with human support, satisfaction with economic state, symptom of depression and positive mental attitude). Factor analysis revealed that the 19 questions could be clearly separated into 6 components in Tokyo and Aichi districts with total variances of 70.8% and 78.4%, respectively. Scores of daily activity and positive mental attitude were significantly lower with older subjects in both men and women. However, scores for other subscales did not differ with age. Primary factors which are considered to affect QOL were compared with the 6 QOL subscales of this study. Being an outpatient had a significant relation to daily activity and satisfaction with health, presence of a spouse to satisfaction with human support, depressive state, positive mental attitude and possession of ones own room to satisfaction with economical state, and belief in religion to positive mental attitude. The results suggest that the present questionnaire include the basic components necessary for evaluation of QOL in elderly subjects living in a community. Further research is required to examine the validity of this questionnaire with correction of questions.

Aged↗
PubMed2000

Immunolocalization of p38 MAP kinase in mouse brain.

p38 has been implicated to play a critical role in regulating apoptosis in PC12 and cerebellar granule cells, and is inactivated in cultured fetal neurons in response to insulin. Though p38 is activated in microglia after ischemia, the physiological functions of p38 in the brain are not well understood. As a first step to elucidate the physiological functions of p38 in the central nervous system, we raised a polyclonal antibody against p38 and performed immunohistochemical examination to demonstrate the localization of p38 in mouse brain. Strong p38 immunoreactivity was apparent in fiber bundles including the olfactory tract, anterior commissure, corpus callosum, cingulum, internal capsule, stria terminalis, fimbria and alveus hippocampi, fornix, stria medullaris, optic chiasm and optic tract. Although similar regions were stained with both anti-p38 and anti-neurofilament antibodies, intense p38 immunoreactivity was often observed in myelin sheath-like structures but not in axons. This is the first demonstration of the localization of p38 in the central nervous system and provides an anatomical basis for understanding physiological roles of p38.

Animals↗
PubMed2000

Synthesis and characterization of a potent and selective protein tyrosine phosphatase inhibitor, 2.

The synthesis and biological activity of a series of 2-[(4-methylthiopyridin-2-yl)methylsulfinyl]benzimidazoles are described. These compounds have potent inhibitory effects against the protein tyrosine phosphatase activity of CD45. Enzymatic analysis with several phosphatases revealed that compound 5a had high specificity for CD45 compared with serine/threonine phosphatases (PP1, PP2A), tyrosine phosphatases (LAR, PTP1B and PTP-S2) and dual phosphatase (VHR).

Benzimidazoles↗
PubMed2000

Activation of p38 mitogen-activated protein kinase is crucial in osteoclastogenesis induced by tumor necrosis factor.

Tumor necrosis factor (TNF) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. Treatment of bone marrow cells with SB203580 but not PD98059 inhibited TNF-induced osteoclast differentiation. In RAW264 cells which differentiate into osteoclast-like multinucleated cells by TNF treatment alone, activation of p38 mitogen-activated protein (MAP) kinase induced by murine TNF was comparable to and independent of the receptor activator of necrosis factor-kappaB ligand. Moreover, the number of multinucleated osteoclasts induced by TNF in bone marrow cell cultures derived from p38 MAP kinase gene deficient mice was significantly less than that from control mice. These results indicate that the p38 MAP kinase pathway plays a crucial role in TNF-mediated osteoclast differentiation.

Animals↗
PubMed2000

Involvement of p38 mitogen-activated protein kinase signaling pathway in osteoclastogenesis mediated by receptor activator of NF-kappa B ligand (RANKL).

The receptor activator of NF-kappaB ligand (RANKL) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. We found that treatment of bone marrow cells with SB203580 inhibited osteoclast differentiation via inhibition of the RANKL-mediated signaling pathway. To elucidate the role of p38 mitogen-activated protein (MAP) kinase pathway in osteoclastogenesis, we employed RAW264 cells which could differentiate into osteoclast-like cells following treatment with RANKL. In a dose-dependent manner, SB203580 but not PD98059, inhibited RANKL-induced differentiation. Among three MAP kinase families tested, this inhibition profile coincided only with the activation of p38 MAP kinase. Expression in RAW264 cells of the dominant negative form of either p38alpha MAP kinase or MAP kinase kinase (MKK) 6 significantly inhibited RANKL-induced differentiation of the cells. These results indicate that activation of the p38 MAP kinase pathway plays an important role in RANKL-induced osteoclast differentiation of precursor bone marrow cells.

Animals↗
PubMed2000

Laforin, defective in the progressive myoclonus epilepsy of Lafora type, is a dual-specificity phosphatase associated with polyribosomes.

The progressive myoclonus epilepsy of Lafora type is an autosomal recessive disorder caused by mutations in the EPM2A gene. EPM2A is predicted to encode a putative tyrosine phosphatase protein, named laforin, whose full sequence has not yet been reported. In order to understand the function of the EPM2A gene, we isolated a full-length cDNA, raised an antibody and characterized its protein product. The full-length clone predicts a 38 kDa laforin that was very close to the size detected in transfected cells. Recombinant laforin was able to hydrolyze phosphotyrosine as well as phosphoserine/threonine substrates, demonstrating that laforin is an active dual-specificity phosphatase. Biochemical, immunofluorescence and electron microscopic studies on the full-length laforin expressed in HeLa cells revealed that laforin is a cytoplasmic protein associated with polyribosomes, possibly through a conformation-dependent protein-protein interaction. We analyzed the intracellular targeting of two laforin mutants with missense mutations. Expression of both mutants resulted in ubiquitin-positive perinuclear aggregates suggesting that they were misfolded proteins targeted for degradation. Our results suggest that laforin is involved in translational regulation and that protein misfolding may be one of the molecular bases of the Lafora disease phenotype caused by missense mutations in the EPM2A gene.

Amino Acid Sequence↗