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S Sakano

Publications and source records attributed to S Sakano.

49 records · Page 3Linked to original sources
PubMed1994

Role of alpha 1-adrenoceptor subtypes which mediate positive chronotropy in neonatal rat cardiac myocytes.

We investigated the involvement of alpha 1-adrenoceptor subtypes in the positive chronotropic response to norepinephrine (NE) in neonatal rat cardiac myocytes at day 3 of culture. The cardiac myocytes at day 3 of culture exhibited a dose-dependent positive chronotropic response to NE in the presence of propranolol, a beta-adrenoceptor antagonist. The positive chronotropic responses to NE were completely antagonized by the alpha 1-adrenoceptor antagonist prazosin. The NE-induced positive chronotropic response was inhibited 68% by the alpha 1B-adrenoceptor antagonist, chloroethylclonidine (CEC), but partially (41%) so by the alpha 1A-adrenoceptor antagonist, WB4101. In the membrane fraction derived from cardiac myocytes at day 3 of culture, pretreatment with CEC decreased the Bmax of the alpha 1-adrenoceptor to 22% of the control value. The NE-induced positive chronotropic response was inhibited 62 and 77% by the voltage-gated Ca2+ channel blocker such as nifedipine and verapamil, respectively. These findings indicate (1) that cultured neonatal rat cardiac myocytes possess both alpha 1-adrenoceptor subtypes, i.e., alpha 1A and alpha 1B, (2) that the predominant alpha 1-adrenoceptor subtypes mediating NE-induced positive chronotropy in neonatal rat cardiac myocytes at day 3 of culture are alpha 1B-subtypes, and (3) that NE-induced positive chronotropy may be caused via voltage-gated Ca2+ channel activation.

Animals↗
PubMed1994

Multiple calcium signaling pathways in Mardin-Darby canine kidney cells.

Effects of various receptor agonists on cytoplasmic Ca2+ concentration ([Ca2+]i) were examined in fura-2-loaded Mardin-Darby canine kidney (MDCK) monolayer cells. Carbachol (100 microM) increased [Ca2+]i which slightly declined to a sustained increase in [Ca2+]i. On the other hand, [Ca2+]i elevated by 100 nM bradykinin (BK) declined to a resting level of [Ca2+]i even in the presence of BK. After washout of BK, the subsequent addition of a higher concentration of BK (1 microM) caused a smaller increase in [Ca2+]i than that induced by 100 nM BK. Isoproterenol (100 microM) did not increase [Ca2+]i by itself but caused an transient increase in [Ca2+]i in the presence of 1 mM isobutyl-methylxanthine (IBMX). Prostaglandin E1 (1 microM) resulted in a slight increase in [Ca2+]i which was potentiatedin the presence of 1 mM IBMX. The microsomal Ca(2+)-ATPase inhibitor thapsigargin (100 nM) caused a sustained increase in [Ca2+]i. These results suggest that MDCK cells have multiple Ca2+ signaling pathways which may regulate epithelial cell functions.

1-Methyl-3-isobutylxanthine↗
PubMed1994

Characterization of mouse non-receptor tyrosine kinase gene, HYL.

We previously reported a novel human non-receptor tyrosine kinase gene, HYL (hematopoietic consensus tyrosine-lacking kinase) (Sakano et al., 1994), which consists of each of the SH2 (src homology 2), SH3 and tyrosine kinase catalytic domains. HYL has unique structural features shared with CSK (C-terminal Src kinase). Recently it has also been reported that matk (Bennett et al., 1994) and Ctk (Klages et al., 1994) are isolated as novel kinases with structural similarity to CSK. Comparisons of cDNA sequence indicate the HYL, matk and Ctk are the same gene. We further characterized the mouse HYL genomic structure and HYL mRNA expression in mouse brain. The mouse HYL gene is distributed over 5.8 kb and is composed of 12 exons. The exon-intron organization is almost identical with that of human CSK. The mouse HYL gene was assigned to the R-positive C1 band of chromosome 10 by fluorescent in situ hybridization. RNA in situ hybridization demonstrated the broad distribution of HYL mRNA expression in various neuronal cells. Especially, strong signals were detected in Purkinje cells, pyramidal cells in the hippocampus, granule cells in the dentate gyrus, and mitral cells in the olfactory bulb, indicating that mRNA expression of HYL in brain is very similar to that of SRC-family kinases. These findings establish close relationship between the HYL and CSK genes and also suggest that HYL may play an important role in signal transduction through SRC-family kinases in the central nervous system.

Animals↗
PubMed1994

Molecular cloning of a novel non-receptor tyrosine kinase, HYL (hematopoietic consensus tyrosine-lacking kinase).

We identified a novel non-receptor tyrosine kinase from a human megakaryoblastic cell line, UT-7, by means of a PCR-based cloning method. The HYL gene contained a SH2 and SH3 domain and a tyrosine kinase catalytic domain. The deduced amino acid sequence of the protein encoded by this gene was most homologous to CSK (c-src kinase). This gene and CSK shared some unique structural properties such as the absence of a myristylation signal and phosphorylation sites of tyrosine residues corresponding to tyrosines 416 and 527 of chicken p60c-src. Unlike CSK, the SH3 domain of HYL was unique since the ALYDY motif was absent. Northern blot analysis revealed a 2.2 kb transcript in various myeloid cell lines but not in adult tissues except for the brain and the lung, whereas CSK mRNA was ubiquitously expressed. The expression of HYL was upregulated when these myeloid cells were differentiated by induction with phorbol myristate acetate. We named this gene, hematopoietic consensus tyrosine-lacking kinase, HYL. The HYL gene was assigned to chromosome 19 at band p13. It is suggested that HYL plays a significant role in the signal transduction of hematopoietic cells.

Amino Acid Sequence↗
PubMed1993

[Analysis of proliferating cell nuclear antigen and nucleolar organizer region in testicular tumors].

Immunohistochemical staining using the monoclonal antibody of proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organizer region associated protein (AgNOR) staining were performed on 28 paraffin-embedded testicular tumors, and their correlation was assessed according to histological type, clinical staging and tumor markers. PCNA positive rates and AgNOR numbers in nuclei were 57.9%, 4.38 in seminomas, 63.4%, 5.79 in embryonal carcinomas, 37.7%, 2.63 in teratomas, 61.3%, 4.43 in yolk sac tumors, 79.5%, 7.12 in choriocarcinomas, and 20.9%, 3.03 in cells of the normal seminiferous tubule, respectively. In pure seminomas, the PCNA positive rates and AgNOR numbers of the stage II to III group (72.6%, 4.75) were higher than those of the stage I group (47.8%, 3.67), but there was no significant difference between the two groups. There was a significant correlation between PCNA positive rate and AgNOR number in all specimens (r = 0.76, p < 0.002). These findings indicate that PCNA and AgNOR are suitable indicators for proliferative activity of testicular tumors.

Adult↗
PubMed1993

[Two cases with acquired immunodeficiency syndrome in our hospital].

We report two cases of AIDS whom we have recently experienced. One patient was a 54-year-old man who admitted our hospital due to third degree burn. In this case, we did not know whether or not he was suffered from AIDS, when he was delivered by the ambulance. In autopsy, pneumocystis carinii pneumonia and renal tuberculosis were found in addition to marked decrease of T cells in lymph nodes. The other patient was a 40-year-old man with remarkable symptoms of central nervous system. Route of infection of HIV is unknown. He had dementia, left hemiplegia, bulbar palsy, progressed to rigid decorticate posture and died of respiratory arrest due to involvement of the brain stem, despite of treatment including use of 3'-azido-2',3'-dideoxythymidine (AZT). Magnetic resonance (MR) images showed progressive cerebral atrophy and a diffuse high signal intensity area of cerebral white matter on T2-weighted MR images, suggesting the diagnosis of HIV-induced encephalopathy.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Successful documentation by coronary angiography of spontaneous simultaneous multivessel coronary spasm in a variant angina patient: a case report].

A 59-year old female who complained of chest discomfort was admitted to our hospital. Electrocardiogram (ECG) on admission and treadmill exercise test showed negative for ischemia. She underwent coronary arteriography. Initial angiography showed there was no significant coronary arterial stenosis. However, when we were preparing the spasm provocation test, she complained of the same kind of chest discomfort as she had felt before. We found that ST segment was elevated in both the anterior and inferior leads on the ECG. Coronary arteriography showed that severe spasm occurred in both the left anterior descending artery (Seg. 6) and the right coronary artery (Seg. 1). Heart rate decreased and electromechanical dissociation occurred. She temporarily lost consciousness. After cardiopulmonary resuscitation, she recovered and the elevation of ST segment returned on the ECG. This is the first case report which has documented spontaneous simultaneous multivessel coronary spasm by coronary arteriography.

Angina Pectoris, Variant↗
PubMed1993

Collagen and alkaline phosphatase gene expression during bone morphogenetic protein (BMP)-induced cartilage and bone differentiation.

Endochondral bone formation induced by bone morphogenetic protein (BMP) involves expression of collagen Types I and II and alkaline phosphatase (ALP) genes. Expression of these genes was studied in mice after implantation of BMP. The amount of Type I collagen mRNA increased from Day 3 to Day 7, when mesenchymal cell aggregation was observed. On Day 17, Type I collagen mRNA expression was correlated with an increased number of osteoblasts. Type II collagen mRNA increased from Day 7 and coincided with chondroblast appearance. This increase was suppressed by Day 17, although hypertrophic and degenerative chondrocytes were present. Alkaline phosphatase mRNA increased markedly from Day 7 with the appearance of chondroblasts. The high level of ALP mRNA continued until Day 11, during chondrogenesis. Mineral deposition was first observed roentgenographically on Day 11. Thus, BMP-induced bone formation occurs with the expression of collagen Types I and II and ALP genes.

Alkaline Phosphatase↗
PubMed1988

Direct determination of the blood concentration of halogenated anesthetic agents by gas chromatography.

The direct determination by gas chromatography of blood levels of anesthetic agents has been difficult because of the water content of blood. In the present study, the method of Yokota et al. (1967) was modified by improving the packing materials of the column, the blood sample vaporizer and the flow-path during analysis. As a result, accurate and reproducible determination of halothane, enflurane and isoflurane dissolved in blood was achieved. With this system, blood in which halothane, enflurane and isoflurane had been dissolved could be analyzed without changing the column between samples. Moreover, each sample was prepared in less than 10 min, and more than 100 consecutive determinations could be made with excellent reproducibility. The coefficient of variation was less than 3.8%.

Chromatography, Gas↗
PubMed1981

Biotransformation of aloenin, a bitter glucoside constituent of Aloe arborescens, by rats.

Aloenin has been established to be 4-methoxy-6-(2-beta-D-glucopyranosyloxy-4-hydroxy-6-methylphenyl)-2-pyrone; it shows an inhibitory activity for gastric juice secretion. Rats metabolized it to 4-methoxy-6-(2,4-dihydroxy-6-methylphenyl)-2-pyrone, 2,5-dimethyl-7-hydroxychromone and glucose, which were excreted in the feces and the urine. The distribution of the radioactivity originating from 14C-labeled aloenin was studied. The tracer found in the kidney and the liver reached 60% of the amount administered 24 h after feeding and decreased rapidly in the next 24 h.

Animals↗