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Y Ishikawa

Publications and source records attributed to Y Ishikawa.

At least 145 records · Page 8Linked to original sources
PubMed2001

Differential serodiagnosis of cystic and alveolar echinococcosis using native and recombinant antigens in Japan.

Our group at Asahikawa Medical College has established differential serodiagnosis for zoonotic larval cestodiases such as alveolar echinococcosis (AE), cystic echinococcosis (CE) and neurocysticercosis (NCC) using purified specific antigens. In this brief review, we introduce (a) four imported CE cases in Japan, easily identified serologically, (b) most recent advances in serology for differentiation of AE and monitoring of prognosis of AE in Japan. It includes application of affinity purified Em18 and prototype of a recombinant Em18 antigen. Serology using affinity purified Em18 antigens is showing much higher sensitivity for detection of AE cases which are usually undetectable by the ongoing serology for AE authorized in Hokkaido, Japan. As serology for AE, CE or NCC is still not popular in the majority of Asian countries, we expect that this review paper stimulates researchers who are interested in serology or serodiagnosis for these larval cestodiases including AE, CE and NCC.

Animals↗
PubMed2000

Bioflavonoid quercetin inhibits mitosis and apoptosis of glomerular cells in vitro and in vivo.

Bioflavonoids have been regarded as therapeutic agents for a wide range of disease including inflammation. In this report, we investigated effects of bioflavonoid quercetin on mitosis and apoptosis of glomerular cells in vitro and in vivo. Serum-stimulated rat mesangial cells were treated with or without quercetin, and total cell number, percentages of mitotic cells, and incorporation of [(3)H]-thymidine were evaluated. All three assays showed that mitogenic activity of mesangial cells was markedly attenuated by quercetin. To examine the effect of quercetin on apoptosis, mesangial cells were pretreated with or without quercetin and stimulated by hydrogen peroxide or tumor necrosis factor-alpha. Hoechst staining and DNA ladder assay showed that both apoptotic responses were dramatically inhibited by quercetin. We further investigated effects of quercetin on in vivo mitosis and apoptosis of glomerular cells. Rats were administered with or without quercetin intraperitoneally, and nephrotoxic serum nephritis was induced. Immunohistochemical analyses showed that treatment with quercetin significantly reduced the number of proliferating cell nuclear antigen (+) cells and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (+) cells in the glomerulus. These data suggested that quercetin has the potential for inhibiting mitosis and apoptosis of glomerular cells both in vitro and in vivo.

Animals↗
PubMed2000

p38 mitogen-activated protein kinase regulates low potassium-induced c-Jun phosphorylation and apoptosis in cultured cerebellar granule neurons.

Cultured rat cerebellar granule neurons are widely used as a model system for studying neuronal apoptosis. After maturation by culturing in medium containing 26 mm potassium (high K(+)), changing to medium containing 5 mm potassium (low K(+); LK) rapidly induces neuronal apoptosis. Then over 50% of granule cells die within 24 h. However, the molecular mechanisms by which the LK-induced apoptosis occurs in cultured cerebellar granule cells remain unclear. In the present study, we found that p38 MAP kinase (p38) was an important factor for LK-induced apoptosis. Three hours after changing to LK medium, p38 was markedly activated. In addition, SB203580, a specific inhibitor of p38, strongly inhibited the phosphorylation and expression of c-Jun in LK-induced apoptosis of cultured cerebellar granule cells. In vitro kinase assay using glutathione S-transferase-c-Jun as a substrate showed that p38 directly phosphorylated c-Jun. Furthermore, in the presence of SB203580, about 80% of neurons survived. These results indicate that p38 regulates LK-induced apoptosis of cerebellar granule neurons.

Animals↗
PubMed2000

Prognostic value of genetically diagnosed lymph node micrometastasis in non-small cell lung carcinoma cases.

The predictive value of lymph node micrometastasis, detected by immunohistochemical or genetic methods, is well appreciated in terms of prognosis. However, a major problem is high false-positive rates, because most methods focus on cytokeratin, which is a component not only of carcinoma but also normal epithelial and nonepithelial cells. Mutant allele-specific amplification (MASA) can detect DNAs derived from cancer cells itself, reportedly with high sensitivity. It was, therefore, used with nested-PCR using p53 or K-ras mutation for analysis of lymph node micrometastasis in non-small cell lung carcinoma (NSCLC) patients in the present study, in comparison with the immunohistochemical method using an anti-cytokeratin reagent for the same samples. Lymph nodes from 31 NSCLC patients with p53 and K-ras mutated tumors (30 and 1, respectively) staged as pathological (p)-T1-4 N0-1 and M0 were examined. Genetic and immunohistochemical methods demonstrated positive reactions in 34 (15%) and 61 (27%) of 229 lymph nodes, respectively (9 cases, 29%, and 24 cases, 77%). The concordance with the two methods was 77%, but 13 (39%) of 34 genetically positive lymph nodes could not be detected by immunohistochemistry (IHC). Of 22 cases with p-N0 disease, 6 (27%) were genetically positive in hilar and/or mediastinal lymph nodes, and 4 (67%) of them died after cancer relapse. In contrast, none of the patients without micrometastasis died of cancer (P < 0.001, log rank analysis). Of the same p-N0 patients, 17 (77%) were positive by IHC, and 4 (24%) of them died of cancer, whereas 5 negative patients did not suffer cancer relapse. Survival did not significantly differ between cases positive and negative (P = 0.246) by IHC. According to the g-N (N factor restaged by a genetic method), patients with g-N1 and g-N2 disease had a shorter survival than those with g-N0 disease (P = 0.042 and P < 0.001, respectively). However, no significant difference was observed with grading by IHC. Thus, detection of micrometastasis in regional lymph nodes with the MASA method, in other words with a carcinoma-specific marker, is of greater prognostic significance for early stage NSCLC patients than immunohistochemical results. This approach should facilitate selection of patients for whom postoperative adjuvant chemotherapy should be performed.

Adenocarcinoma↗
PubMed2000

NAD(P)+-NAD(P)H models. 90. Stereoselection controlled by electronic effect of a carbonyl group in oxidation of NAD(P)H analog.

4-Monodeuterated NAD(P)H model compounds (1,4,6,7-tetrahydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]az epin; 11Me-MMPAH) have been oxidized with a series of p-benzoquinone and its derivatives in the presence of Mg2+. The models have an axial chirality with respect to the orientation of carbonyl dipole, the dihedral angle of which is larger than 55 degrees out of the plane of dihydropyridine ring. Without Mg2+, the anti- (with respect to the carbonyl dipole) hydrogen is 3 to 32 times more reactive than the corresponding syn-hydrogen, whereas, when Mg2+ is present in the system, the selectivity is shifted toward the syn-preferency. Mg2+ plays the role of a Lewis acid catalyst to control the stereochemistry at the same time as it catalyzes the reaction.

Catalysis↗
PubMed2000

Effects of hypoxia on cholesterol metabolism in human monocyte-derived macrophages.

We assessed the metabolism of low density lipoprotein (LDL) of human monocyte-derived macrophages under hypoxia. The specific binding and association of 125I-labeled LDL (125I-LDL) were not changed under hypoxia compared to normoxia. However, the degradation of 125I-LDL under hypoxia decreased to 60%. The rate of cholesterol esterification under hypoxia was 2-fold greater on incubation with LDL or 25-hydroxycholesterol. The cellular cholesteryl ester content was also greater under hypoxia on incubation with LDL. Secretion of apolipoprotein E into the medium was not altered under hypoxia, suggesting that apolipoprotein E independent cholesterol efflux may be reduced under hypoxia. Thus, hypoxia affects the intracellular metabolism of LDL, stimulates cholesterol esterification, and enhances cholesteryl ester accumulation in macrophages. Hypoxia is one of the important factors modifying the cellular lipid metabolism in arterial wall.

Apolipoproteins E↗
PubMed2000

Introduction of a foreign gene into medakafish using the particle gun method.

We developed a procedure to introduce a foreign gene into fertilized eggs of medakafish (Oryzias latipes) using the particle gun method, which is one of the easiest and most reliable techniques for gene transfer. A plasmid construct with the green fluorescence protein (GFP) gene driven by the madakafish beta-actin gene promoter was successfully introduced into eggs, and the expression of GFP was observed in 20% of the primary transfectant (chimera) fish. In addition, germ line transmission of GFP was observed in 13% of the GFP-positive primary transfectant fish. The new application described here should enable us to investigate gene expression using the fish model on a routine basis without high technical sophistication. J. Exp. Zool. 287:285-293, 2000.

Animals↗
PubMed2000

Persistent increase in the amount of aquaporin-5 in the apical plasma membrane of rat parotid acinar cells induced by a muscarinic agonist SNI-2011.

SNI-2011 induces the long-lasting increase in the amount of aquaporin-5 (AQP5) in apical plasma membranes (APMs) of rat parotid acini in a concentration-dependent manner. This induction was inhibited by p-F-HHSiD, U73122, TMB-8, or dantrolene but not by bisindolmaleimide or H-7, indicating that SNI-2011 acting at M(3) muscarinic receptors induced translocation of AQP5 via [Ca(2+)](i) elevation but not via the activation of protein kinase C. In contrast, acetylcholine induced a transient translocation of AQP5 to APMs. SNI-2011 induces long-lasting oscillations of [Ca(2+)](i) in the presence of extracellular Ca(2+). Thus, SNI-2011 induces a long-lasting translocation of AQP5 to APMs coupled with persistent [Ca(2+)](i) oscillations.

Animals↗
PubMed2000

Analysis of human V alpha 24+ CD4+ NKT cells activated by alpha-glycosylceramide-pulsed monocyte-derived dendritic cells.

Human V alpha 24+ NKT cells with an invariant TCR (V alpha 24-J alpha Q) have been shown to be specifically activated by synthetic glycolipids such as alpha-galactosylceramide and alpha-glucosylceramide in a CD1d-restricted and V alpha 24 TCR-mediated manner. We recently characterized V alpha 24+ CD4- CD8- double negative (DN) NKT cells using alpha-galactosylceramide-pulsed monocyte-derived dendritic cells. Here, we compare V alpha 24+ CD4+ NKT cells with human V alpha 24+ DN NKT cells from the same donor using alpha-galactosylceramide-pulsed monocyte-derived dendritic cells. Human V alpha 24+ CD4+ NKT cells were phenotypically and functionally similar to the human V alpha 24+ DN NKT cells characterized previously. Both of them use V alpha 24-J alpha Q-V beta 11 TCR and express CD161 (NKR-P1A), but not the other NK receptors tested so far. They also produce cytokines such as IL-4 and IFN-gamma, and, in regard to IL-4 production, V alpha 24+ CD4+ NKT cells produce more IL-4 than V alpha 24+ DN NKT cells. The cells exhibit marked cytotoxic activity against the U937 tumor cell line, but not against the NK target cell line, K562. Although at least some of the factors responsible for the stimulation of V alpha 24+ NKT cells have been clarified, little is known regarding the killing phase of these cells. Here we show that the cytotoxic activity of V alpha 24+ NKT cells against U937 cells is mediated mainly through the perforin pathway and that ICAM-1/LFA-1 as well as CD44/hyaluronic acid interactions are important for the effector phase of V alpha 24+ NKT cell-mediated cytotoxicity against U937 cells.

Antigens, CD1↗
PubMed2000

Selective involvement of superoxide anion, but not downstream compounds hydrogen peroxide and peroxynitrite, in tumor necrosis factor-alpha-induced apoptosis of rat mesangial cells.

Tumor necrosis factor-alpha (TNF-alpha) induces reactive oxygen species (ROS) that serve as second messengers for intracellular signaling. Currently, precise roles of individual ROS in the actions of TNF-alpha remain to be elucidated. In this report, we investigated the roles of superoxide anion (O-(2)), hydrogen peroxide (H(2)O(2)), and peroxynitrite (ONOO(-)) in TNF-alpha-triggered apoptosis of mesangial cells. Mesangial cells stimulated by TNF-alpha produced O-(2) and underwent apoptosis. The apoptosis was inhibited by transfection with manganese superoxide dismutase or treatment with a pharmacological scavenger of O-(2), Tiron. In contrast, although exogenous H(2)O(2) induced apoptosis, TNF-alpha-triggered apoptosis was not affected either by transfection with catalase cDNA or by treatment with catalase protein or glutathione ethyl ester. Similarly, although ONOO(-) precursor SIN-1 induced apoptosis, treatment with a scavenger of ONOO(-), uric acid, or an inhibitor of nitric oxide synthesis, N(G)-nitro-L-argininemethyl ester hydrochloride, did not affect the TNF-alpha-triggered apoptosis. Like TNF-alpha-induced apoptosis, treatment with a O-(2)-releasing agent, pyrogallol, induced typical apoptosis even in the concurrent presence of scavengers for H(2)O(2) and ONOO(-). These results suggested that, in mesangial cells, TNF-alpha induces apoptosis through selective ROS. O-(2), but not H(2)O(2) or ONOO(-), was identified as the crucial mediator for the TNF-alpha-initiated, apoptotic pathway.

Animals↗
PubMed2000

Immunodetection of adenylyl cyclase protein in tissues.

Immunodetection of the adenylyl cyclase isoforms has been difficult in tissues because of its low quantity of protein expression. We have developed a one-step cellular protein purification method that enables a simple immunodetection of the adenylyl cyclase isoforms. The type I isoform was detected exclusively in the brain. The type III isoform was detected in the brain and lungs. Further, the protein expression of type III adenylyl cyclase in lungs changed ontogenically and was the lowest in neonates. Thus, the comparison of the amount of certain adenylyl cyclase isoforms protein in each tissue is now feasible using our method.

Adenylyl Cyclases↗
PubMed2000

Involvement of protein kinase C in taxol-induced polyploidization in a cultured sarcoma cell line.

Taxol was found to inhibit the proliferation and to induce the polyploidization of cultured methylcholanthrene-induced sarcoma cells (Meth-A cells). To investigate whether protein kinase C is involved in taxol-induced polyploidization, phorbol 12-myristate 13-acetate (PMA), which regulates the activity of protein kinase C, was used along with taxol to treat the cells. We found that PMA did not interfere with the proliferation and did not induce polyploidization by itself. However, at low concentration, taxol, which by itself did not induce polyploidization, clearly induced polyploidization in the presence of PMA. To explore the mechanism by which PMA potentiates polyploidization, the levels of the G1 checkpoint-related proteins cyclin E and cdk2, and those of the G2 checkpoint-related proteins cyclin B and cdc2 were determined by flow cytometry. We found that both G1 and G2 checkpoint-related proteins increased during the induction of polyploidization. To verify the relationship between protein kinase C and tubulin polymerization, flow cytometry was used to determine the total content of tubulin protein, and morphological observation was used to examine spindle organization. PMA did not affect the taxol-induced increase in tubulin protein, but markedly potentiated taxol-induced spindle disorganization. These findings suggest that protein kinase C plays an important role in regulating the induction of polyploidization in Meth-A cells.

Animals↗
PubMed2000

Determinants of the cardiomyopathic phenotype in chimeric mice overexpressing cardiac Gsalpha.

Mice with overexpressed cardiac Gsalpha develop cardiomyopathy, characterized by myocyte hypertrophy and extensive myocardial fibrosis. The cardiomyopathy likely involves chronically enhanced beta-adrenergic signaling, because it can be blocked with long-term propranolol treatment. It remains unknown whether the genotype of the myocyte is solely responsible for the progressive pathological changes. A chimeric population in the heart should answer this question. Accordingly, we developed a chimeric animal, which combined cells from a transgenic overexpressed Gsalpha parent and a Rosa mouse containing the LacZ reporter gene, facilitating identification of the non-Gsalpha cells, which express a blue color with exposure to beta-galactosidase. We studied these animals at 14 to 17 months of age (when cardiomyopathy should have been present), with the proportion of Gsalpha cells in the myocardium ranging from 5% to 88%. beta-Galactosidase staining of the hearts demonstrated Gsalpha and Rosa cells, exhibiting a mosaic pattern. The fibrosis and hypertrophy, characteristic of the cardiomyopathy, were not distributed randomly. There was a direct correlation (r=0.85) between the extent of myocyte hypertrophy (determined by computer imaging) and the quantity of Gsalpha cells. The fibrosis, determined by picric acid Sirius red, was also more prominent in areas with the greatest Gsalpha cell density, with a correlation of r=0.88. Thus, the overexpressed Gsalpha can exert its action over the life of the animal, resulting in a local picture of cardiomyopathic damage in discrete regions of the heart, where clusters of the overexpressed Gsalpha cells reside, sparing the clusters of normal cells derived from the normal Rosa parent.

Animals↗
PubMed2000

Continuous erythropoietin delivery by muscle-targeted gene transfer using in vivo electroporation.

It has been demonstrated that gene transfer by in vivo electroporation of mouse muscle increases the level of gene expression by more than 100-fold over simple plasmid DNA injection. We tested continuous rat erythropoietin (Epo) delivery by this method in normal rats, using plasmid DNA expressing rat Epo (pCAGGS-Epo) as the vector. A pair of electrodes was inserted into the thigh muscles of rat hind limbs and 100 microg of pCAGGS-Epo was injected between the electrodes. Eight 100-V, 50-msec electric pulses were delivered through the electrodes. Each rat was injected with a total of 400 microg of pCAGGS-Epo, which was delivered to the medial and lateral sides of each thigh. The presence of vector-derived Epo mRNA at the DNA injection site was confirmed by RT-PCR. The serum Epo levels peaked at 122.2 +/- 33.0 mU/ml on day 7 and gradually decreased to 35.9 +/- 18.2 mU/ml on day 32. The hematocrit levels increased continuously, from the preinjection level of 49.5 +/- 1.1 to 67.8 +/- 2.2% on day 32 (p < 0.001). In pCAGGS-Epo treated rats, endogenous Epo secretion was downregulated on day 32. In a control experiment, intramuscular injection of pCAGGS-Epo without subsequent electroporation did not significantly enhance the serum Epo levels. These results demonstrate that muscle-targeted pCAGGS-Epo transfer by in vivo electroporation is a useful procedure for the continuous delivery of Epo.

Animals↗