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Biomedical subjects

Shinji Sato

Publications and source records attributed to Shinji Sato.

At least 19 recordsLinked to original sources
PubMed2004

Scaffold protein JSAP1 is transported to growth cones of neurites independent of JNK signaling pathways in PC12h cells.

The c-Jun NH(2)-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 [JSAP1; also known as JNK-interacting protein 3 (JIP3)] has been identified as a scaffold protein for JNK mitogen-activated protein kinase signal transduction pathways and as a cargo adapter in the conventional kinesin-mediated transport system. Furthermore, a functional relationship between UNC-16, the C. elegans ortholog of JSAP1, and JNK signaling has been established genetically. In this study, we first demonstrated that the kinesin light chain is required for the targeting and localization of JSAP1 to the tips of neurites in PC12h cells. Furthermore, to understand whether JNK signaling is involved in kinesin-mediated JSAP1 trafficking, we established stable PC12h cell lines that expressed wild-type JSAP1 or its mutant lacking the JNK-binding domain (JBD). Immunocytochemical studies of the cell lines indicated that the mutant JSAP1 was localized to the growth cones of differentiating PC12h cells in a similar manner to wild-type JSAP1. Taken together, these results suggest that the proper subcellular localization of JSAP1 along microtubules probably does not require JNK signaling.

Animals↗
PubMed2004

Alterations in glucose metabolism induce hypothermia leading to tau hyperphosphorylation through differential inhibition of kinase and phosphatase activities: implications for Alzheimer's disease.

Alzheimer's disease (AD) brains contain neurofibrillary tangles (NFTs) composed of abnormally hyperphosphorylated tau protein. Regional reductions in cerebral glucose metabolism correlating to NFT densities have been reported in AD brains. Assuming that reduced glucose metabolism might cause abnormal tau hyperphosphorylation, we induced in vivo alterations of glucose metabolism in mice by starvation or intraperitoneal injections of either insulin or deoxyglucose. We found that the treatments led to abnormal tau hyperphosphorylation with patterns resembling those in early AD brains and also resulted in hypothermia. Surprisingly, tau hyperphosphorylation could be traced down to a differential effect of low temperatures on kinase and phosphatase activities. These data indicate that abnormal tau hyperphosphorylation is associated with altered glucose metabolism through hypothermia. Our results imply that serine-threonine protein phosphatase 2A plays a major role in regulating tau phosphorylation in the adult brain and provide in vivo evidence for its crucial role in abnormal tau hyperphosphorylation in AD.

Alzheimer Disease↗
PubMed2003

Effects of fluoranthene, a polycyclic aromatic hydrocarbon, on cAMP-dependent anion secretion in human airway epithelia.

The human respiratory tract is constantly exposed to polycyclic aromatic hydrocarbons (PAHs) through inhalation of atmospheric pollutants. We examined the effects of three PAHs (benzo[a]pyrene, anthracene, and fluoranthene) on the airway ion transport, which is essential for lung defense and normal airway function, using human airway epithelia (Calu-3). These three PAHs had no significant effect on the basal short-circuit current (I(sc)). However, fluoranthene (1-100 microM) applied in the apical compartment potentiated I(sc) in response to cAMP-related agents (isoproterenol, forskolin, and 8-bromo-cAMP). The effects of fluoranthene were unaffected by ellipticine, a PAH receptor antagonist. Estimation of the anionic composition of I(sc) revealed that isoproterenol increased both HCO(3)(-) and Cl(-) transport in the control, whereas it potentiated only Cl(-) transport in the presence of fluoranthene. The fluoranthene-induced modulations of these anion transporters were counteracted by charybdotoxin (ChTx, a hIK-1 channel blocker). Fluoranthene gradually augmented the ChTx-sensitive K(+) current (I(K)) across the basolateral membrane, accompanied by a sustained increase in the cytosolic Ca(2+) concentration ([Ca(2+)](i)). In the presence of fluoranthene, however, a much larger hIK-1-dependent I(K) was identified by the application of 8-bromo-cAMP without concomitant elevation of [Ca(2+)](i). These results suggest that fluoranthene switches from cAMP-dependent HCO(3)(-) secretion to Cl(-) secretion through the hIK-1 channel, whose sensitivity to protein kinase A may be up-regulated by the sustained [Ca(2+)](i) elevation produced by this chemical.

Anions↗
PubMed2003

Apical and basolateral ATP-induced anion secretion in polarized human airway epithelia.

The present study investigated mechanisms underlying apical and basolateral P2Y(1)-mediated Cl(-) secretion in human airway epithelial cells. Apical and basolateral ATP induced short-circuit currents (I(sc)) with different properties via P2Y(1) receptors. The former comprised an immediate rise followed by a slow attenuation, whereas the latter was a transient rise with a higher peak and shorter duration (< 2 min). The actions of ATP were simulated by those of ADP, ADPbetaS, and ATPgammaS. Antagonists of phosphatidylinositol-phospholipase C (U73122, ET-18-OCH(3)) were without any effect on the bilateral ATP-induced I(sc), which were, in contrast, attenuated by a phosphatidylcholine-phospholipase C inhibitor (D609) and an adenylate cyclase inhibitor (SQ22536). The responses to ATP from either aspect were also sensitive to an intracellular Ca(2+) chelator, 1,2-bis (o-amino-phenoxy)-ethane-N,N,N',N'-tetraacetic acid tetra-(acetoxymethyl)-ester, or a Ca(2+)-activated K(+) channel inhibitor, charybdotoxin, although differential Ca(2+) signals were concomitant with each reaction. Nystatin permeabilization studies revealed a good correlation between the I(sc) and the basolateral K(+) current rather than the apical Cl(-) current under ATP-stimulated conditions. In conclusion, apical and basolateral P2Y(1) receptors couple with both phosphatidylcholine-phospholipase C and adenylate cyclase, leading to Cl(-) secretion, whose rate is essentially regulated by the Ca(2+)-activated K(+) channel-mediated K(+) conductance. This suggests the importance of this channel in airway mucociliary clearance.

Adenine↗
PubMed2003

ATP release triggered by activation of the Ca2+-activated K+ channel in human airway Calu-3 cells.

Airway mucociliary clearance is subject to the autocrine/paracrine regulation of extracellular nucleotides released from the airway epithelial cells. The present study was performed in pursuit of effective modulators of ATP release under physiologic conditions in polarized human airway epithelial cells (Calu-3). Neither isoproterenol, forskolin, nor ionomycin augmented extracellular ATP release detected by luciferase assay. However, direct activation of the human intermediate conductance, Ca(2+)-activated K(+) channel (hIK-1) by 1-ethyl-2-benzimdazolinone (1-EBIO, 1 mM) and chlorzoxazone (CZ, 1 mM) increased ATP release predominantly in the apical compartment. Measurement of fluo-3 signals revealed that 1-EBIO- and CZ-stimulated cytosolic Ca(2+) mobilization was suppressed by the presence of MRS-2179, a specific P2Y(1) receptor antagonist. The hIK-1-mediated ATP release was inhibited by a hIK-1 blocker (charybdotoxin), and an Na(+)-K(+)-2Cl(-) cotransport blocker (bumetanide) without interruption by GdCl(3), an inhibitor of stretch-activated nonselective cation (SA) channels, or glybenclamide, a blocker of the cystic fibrosis transmembrane conductance regulator (CFTR). These results suggest that a cell volume decrease via the hIK-1-mediated KCl loss and the resultant induction of a regulatory volume increase via the Na(+)-K(+)-2Cl(-) transporter may trigger release of ATP, which causes P2Y(1)-mediated Ca(2+) mobilization, through mechanisms unrelated to the CFTR and SA channels.

Adenosine Diphosphate↗
PubMed2003

A sensitive transcriptome analysis method that can detect unknown transcripts.

We have developed an AFLP-based gene expression profiling method called 'high coverage expression profiling' (HiCEP) analysis. By making improvements to the selective PCR technique we have reduced the rate of false positive peaks to approximately 4% and consequently the number of peaks, including overlapping peaks, has been markedly decreased. As a result we can determine the relationship between peaks and original transcripts unequivocally. This will make it practical to prepare a database of all peaks, allowing gene assignment without having to isolate individual peaks. This precise selection also enables us to easily clone peaks of interest and predict the corresponding gene for each peak in some species. The procedure is highly reproducible and sensitive enough to detect even a 1.2-fold difference in gene expression. Most importantly, the low false positive rate enables us to analyze gene expression with wide coverage by means of four instead of six nucleotide recognition site restriction enzymes for fingerprinting mRNAs. Therefore, the method detects 70-80% of all transcripts, including non-coding transcripts, unknown and known genes. Moreover, the method requires no sequence information and so is applicable even to eukaryotes for which there is no genome information available.

Animals↗
PubMed2003

Selective determination of ammonium ions by high-speed ion-exclusion chromatography on a weakly basic anion-exchange resin column.

This paper describes an ion-exclusion chromatographic system for the rapid and selective determination of ammonium ion. The optimized ion-exclusion chromatographic system was established with a polymethacrylate-based weakly basic anion-exchange resin column (TSKgel DEAE-5PW) as the separation column, an aqueous solution containing 0.05 mM tetramethylammonium hydroxide (pH 9.10) as eluent with conductimetric detection for the analyte determination. Under the optimum chromatographic conditions, ammonium ion was determined within 2.3 min with a detection limit (S/N=3) better than 0.125 microM. Ammonium ion in rain and river waters was precisely determined using this ion-exclusion chromatographic system.

Anion Exchange Resins↗
PubMed2003

High-speed simultaneous ion-exclusion/cation-exchange chromatography of anions and cations on a weakly acidic cation-exchange resin column.

The simultaneous ion-exclusion/cation-exchange separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin of 3 microm particle size was used to achieve the simultaneous high-speed separation of anions and cations (Cl(-), NO3(-), SO4(2-), Na(+), K(+), NH4(+), Ca(2+) and Mg(2+)) commonly found in environmental samples. The high-speed simultaneous separation is based on a combination of the ion-exclusion mechanism for the anions and the cation-exchange mechanism for cations. The complete separation of the anions and cations was achieved in 5 min by elution with 15 mM tartaric acid-2.5 mM 18-crown-6 at a flow-rate of 1.5 ml/min. Detection limits at S/N=3 ranged from 0.36 to 0.68 microM for anions and 0.63-0.99 microM for cations. This method has been applied to the simultaneous determination of anions and cations in several environmental waters with satisfactory results.

Anions↗
PubMed2003

Prognostic factors associated with the clinical outcome of cervical intraepithelial neoplasia: a cohort study in Japan.

One hundred and eighty-five Japanese women with cervical intraepithelial neoplasia (CIN) were enrolled in this follow-up study. On the basis of the prevalence of human papillomavirus (HPV) DNA in Japanese cervical cancer patients, HPV types were categorized into three groups as follows: (1) high risk (types 16, 18, 33, 52, and 58), (2) intermediate risk (types 31, 35, 39, 51, 56, 59, 68, and 70), (3) low risk (type 6, 30, 42, 53, 54, 55, 66 and unclassified types). High-risk HPV infection was a risk factor for progression of the disease. The regression rate in the HPV negative group was higher (83.3%) than those in the HPV positive groups, but the differences in regression were no longer significant after adjustment for age and CIN grade. It is also noted that a lower cytomegalovirus IgG level and a smaller number of past pregnancies might be associated with the regression of CIN lesions.

Cohort Studies↗
PubMed2003

The correlation between the response to progestogen treatment and the expression of progesterone receptor B and 17beta-hydroxysteroid dehydrogenase type 2 in human endometrial carcinoma.

OBJECTIVE: In situ metabolism and synthesis of oestrogens are considered to play important roles in the pathogenesis and development of human endometrial endometrioid adenocarcinoma. Approximately 3-5% of patients with these neoplasms are under age 40, some of whom have been treated with progestogen alone as a primary therapy for both atypical endometrial hyperplasia and adenocarcinoma in order to preserve their fertility. Medroxyprogesterone acetate (MPA) has been used extensively in the treatment of both breast and endometrial disorders as an endocrine therapy. However, details of the alterations of in situ oestrogen metabolism following progestogen treatment have yet to be fully elucidated. DESIGN, PATIENTS AND MEASUREMENTS: In this study we examined the immunolocalization of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) types 1 and 2, oestrogen receptor (ER), progesterone receptor (PR)A + PRB, PRB, and Ki67 in progestogen-treated endometrial endometrioid adenocarcinoma (16 cases). We compared our findings both prior to and following treatment. These findings were then correlated with the treatment outcome of individual patients in order to elucidate factors associated with the response to treatment. RESULTS: 17beta-HSD type 2 immunoreactivity was detected in 8/16 cases examined, whereas 17beta-HSD type 1 immunoreactivity was undetected in all cases examined. 17beta-HSD type 2 positive immunostaining, PRA + PRB labelling index (LI), and PRB/PRA + PRB ratio were all significantly higher in cases responding to the treatment than in those not responding. There were no significant correlations between responsive and nonresponsive cases for positive 17beta-HSD type 1 immunostaining, Ki67 LI, ER LI and age. There were no significant differences in the positive immunostaining for 17beta-HSD types 1 and 2, Ki67 LI, ER LI, PRA + PRB LI, age and PRB/PRA + PRB ratio between specimens taken prior to and following progestogen treatment. CONCLUSION: These results suggest that in situ abundance of 17beta-HSD type 2 and PR, especially PRB, can predict the possible response of patients with endometrial carcinoma to progestogen treatment.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Contribution of sympathetic nervous system activity during administration of carvedilol in rats with dilated cardiomyopathy.

We investigated the contribution of the sympathetic nervous system (SNS) in maintaining blood pressure during administration of carvedilol in rats with dilated cardiomyopathy, and examined whether SNS hyperactivity induced by high-dose carvedilol is related to severity of heart failure. The hypotensive effect of carvedilol in rats with heart failure (Group F) was not significantly different to that in rats without (Group N). However, enhancement of the plasma norepinephrine concentration during carvedilol administration in Group F was higher than in Group N. The constitutive plasma NE concentration in Group F (562 +/- 146 pg/ml) was significantly higher than in Group N (203 +/- 55 pg/ml) and there was a significant positive correlation between the heart weight to body weight ratio and the plasma norepinephrine concentration. Values for the maximal effect of the norepinephrine hypertensive effect during norepinephrine intravenous infusion (Emax) decreased, and plasma norepinephrine concentrations at half-maximal effect of the norepinephrine hypertensive effect (EC50) increased in Group F compared with Group N (20.8 +/- 6.1 and 28.6 +/- 2.2 mmHg, and 4.5 +/- 1.9 and 1.5 +/- 0.2 ng/ml, respectively). These results suggested that the number of receptors (Emax) and sensitivity (EC50) to the norepinephrine hypertensive effect decreased in Group F. Changes in these parameters in Group F corresponded with the results of a beta-adrenergic receptor binding assay using I-125 iodocyanopindolol (Bmax = 32 +/- 4 in Group F and 53 +/- 2 fmol/mg protein in Group N). These results showed that the SNS (presynaptic) activity increased and the SNS receptor sensitivity in the blood pressure regulation system decreased in heart failure. Therefore, high-dose carvedilol treatment should be used with caution to avoid worsening heart failure.

Animals↗
PubMed2003

Mirimostim (macrophage colony-stimulating factor; M-CSF) improves chemotherapy-induced impaired natural killer cell activity, Th1/Th2 balance, and granulocyte function.

The purpose of this study was to clarify the effects of mirimostim (macrophage colony-stimulating factor; M-CSF) on immunological functions after chemotherapy. The percentage of natural killer (NK) cells in peripheral blood mononuclear cells (PBMCs), NK cell activity, T-helper cell 1/T-helper cell 2 (Th1/Th2) ratio, and superoxide anion production by granulocytes (granulocyte function) were measured as immunological parameters before and after chemotherapy in 44 patients with primary ovarian cancer who received at least three consecutive courses of postoperative chemotherapy. Patients were observed during the first course of chemotherapy, and 39 patients who presented grade III or IV neutropenia were entered into this study and randomly allocated to an M-CSF-administered group (group 1; 19 patients) and a non-M-CSF-administered group (group 2; 20 patients) for the second course. For the third course, a crossover trial was conducted. In the observation period, chemotherapy significantly impaired the immunological parameters. In particular, those parameters were significantly decreased at day 14 compared to the level before chemotherapy. The values of the parameters of group 1 were significantly higher than those of group 2. In the course of chemotherapy during which M-CSF was administered, 19 of the 39 patients presented grade IV neutropenia, and received granulocyte colony-stimulating factor (G-CSF) between days 7 and 14. We compared the changes of those immunological parameters in the M-CSF alone group and the M-CSF + G-CSF group, and found that the concomitant use of G-CSF did not further improve the parameters. These results indicate that chemotherapy markedly impaired the immunological functions, and that the administration of M-CSF significantly improved the impaired immunological functions.

Adolescent↗
PubMed2003

[A case of ligating both upper and anomalous lower left pulmonary veins in the left upper lobectomy].

A 53-year-old male was anesthetized for left upper lobectomy under one-lung ventilation using a double-lumen endobronchial tube in the lateral position. When the upper left pulmonary vein was ligated, Pao2/FIo2 ratio (PF ratio) was elevated despite the one-lung ventilation. After the operation, the patient was repositioned onto spine position and massive bleeding occurred from the anomalous lower left pulmonary vein, which was ligated during the operation. The lower left pulmonary vein was restored and the bleeding stopped. Because the pulmonary shunt flow from the lower left pulmonary vein had stopped, the PF ratio was unusually elevated. We urge anesthesiologists to pay attention to the arterial blood gas data even when it is better than expected.

Anesthesia, General↗
PubMed2003

Effect of intermittent cyclical etidronate therapy on corticosteroid induced osteoporosis in Japanese patients with connective tissue disease: 3 year followup.

OBJECTIVE: A 3 year prospective randomized study was conducted to clarify the efficacy of intermittent cyclical etidronate therapy on corticosteroid induced osteoporosis. METHODS: A group of 102 Japanese patients were enrolled, each taking > 7.5 mg of prednisolone daily for at least 90 days. Patients were randomly divided into 2 treatment groups: Group E (etidronate) took 200 mg etidronate disodium per day for 2 weeks with 3.0 g calcium lactate and 0.75 microg alphacalcidol daily; Group C (control) took 3.0 g calcium lactate and 0.75 microg alphacalcidol daily. Outcome measurements included changes from baseline in bone mineral density (BMD) of the lumbar spine and the rate of new vertebral fractures at 48 and 144 weeks. RESULTS: The mean (+/- SD) lumbar spine BMD increased 3.7 +/- 5.6% (p < 0.01) and 1.5 +/- 4.1% (NS) from baseline at 48 weeks and 4.8 +/- 6.9% (p < 0.005) and 0.4 +/- 5.0% (NS) from baseline at 144 weeks in Group E and Group C, respectively. The improvement of BMD in Group E was significantly greater than in Group C at 144 weeks (p < 0.01). In 3 subgroups, men and premenopausal and postmenopausal women, the postmenopausal women showed the greatest improvement. Mean percentage change in this subgroup was 10.1 +/- 8.0% and 1.35 +/- 6.4% in Group E and Group C, respectively. We noted that 2 patients in Group C had new vertebral fractures, whereas no fractures were observed in Group E. CONCLUSION: These results indicate that intermittent cyclical etidronate therapy is effective for the prevention and treatment of corticosteroid induced osteoporosis in patients with connective tissue diseases.

Adult↗
PubMed2002

Tau filament formation and associative memory deficit in aged mice expressing mutant (R406W) human tau.

The R406W tau mutation found in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) causes a hereditary tauopathy clinically resembling Alzheimer's disease. Expression of modest levels of the longest human tau isoform with this mutation under the control of the alpha-calcium-calmodulin-dependent kinase-II promoter in transgenic (Tg) mice resulted in the development of congophilic hyperphosphorylated tau inclusions in forebrain neurons. These inclusions appeared as early as 18 months of age. As with human cases, tau inclusions were composed of both mutant and endogenous wild-type tau, and were associated with microtubule disruption and flame-shaped transformations of the affected neurons. Straight tau filaments were recovered from Sarkosyl-insoluble fractions from only the aged Tg brains. Behaviorally, aged Tg mice had associative memory impairment without obvious sensorimotor deficits. Therefore, these mice that exhibit a phenotype mimicking R406W FTDP-17 provide an animal model for investigating the adverse properties associated with this mutation, which might potentially recapitulate some etiological events in Alzheimer's disease.

Aging↗
PubMed2002

Bioelectric toxicity caused by chlorpromazine in human lung epithelial cells.

Endogeneous and exogeneous amine-containing substances possess pneumophilic properties. Among them, tricyclic amphiphilic amine drugs like neuroleptics intensively accumulate in the lung cell membrane and occasionally cause severe respiratory disorders. In the present study, we examined the bioelectric toxicity of chlorpromazine (CPZ), a commonly used neuroleptic, in human lung epithelial cells. CPZ concentration-dependently inhibited the isoproterenol (ISO)-generated short-circuit current (I(sc)) sensitive to a nonselective K(+) channel blocker, clotrimazole (30 microM), but insensitive to a selective Ca(2+)-activated K(+) (K(Ca)) channel blocker, charybdotoxin (ChTx, 100 nM). The effects of apical CPZ on the ISO-induced responses were greater than those of basolateral CPZ. Forskolin- and 8-bromo-cyclic AMP-induced I(sc) were partially prevented by CPZ. Nystatin permeabilization of the monolayers revealed that CPZ attenuated the basolateral K(+) current elicited by ISO more than that elicited by forskolin and that the apical Cl(-) current elicited by forskolin was instead potentiated by CPZ, although it inhibited the ISO-induced Cl(-) current. 1-Ethyl-2-benzimdazolinone (1-EBIO, a K(Ca) channel opener, 500 microM)- and ionomycin (Ca(2+) ionophore, 1 microM)-evoked Cl(-) secretions were also sensitive to CPZ. These results indicate that CPZ inhibits transepithelial Cl(-) transport, affecting at least two different targets: the beta-adrenergic receptor and the basolateral K(+) channels (especially the K(Ca) channel). Electrostatic interactions at the inner surface of the membrane between the protonated amines of CPZ and negatively charged portions of the plasma membrane may be involved in the mechanisms.

1-Propanol↗
PubMed2002

Aberrant tau phosphorylation by glycogen synthase kinase-3beta and JNK3 induces oligomeric tau fibrils in COS-7 cells.

Neurofibrillary tangles (NFTs) are found in a wide range of neurodegenerative disorders, including Alzheimer's disease. The major component of NFTs is aberrantly hyperphosphorylated microtubule-associated protein tau. Because appropriate in vivo models have been lacking, the role of tau phosphorylation in NFTs formation has remained elusive. Here, we describe a new model in which adenovirus-mediated gene expression of tau, DeltaMEKK, JNK3, and GSK-3beta in COS-7 cells produces most of the pathological phosphorylation epitopes of tau including AT100. Furthermore, this co-expression resulted in the formation of tau aggregates having short fibrils that were detergent-insoluble and Thioflavin-S-reactive. These results suggest that aberrant tau phosphorylation by the combination of these kinases may be involved in "pretangle," oligomeric tau fibril formation in vivo.

Alzheimer Disease↗