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K Goto

Publications and source records attributed to K Goto.

At least 55 records · Page 3Linked to original sources
PubMed2001

Gene expression and in situ localization of diacylglycerol kinase isozymes in normal and infarcted rat hearts: effects of captopril treatment.

Diacylglycerol (DG) kinase (DGK) terminates signaling from DG, which serves as an activator of protein kinase C (PKC), by converting DG to phosphatidic acid. DGK is thus regarded as an attenuator of the PKC activity. In rats, five DGK isozymes have been cloned, but little is known about their role in the heart. In this study, the spatiotemporal expression of DGK isozymes was investigated in rat hearts under a normal condition and after myocardial infarction (MI) by in situ hybridization histochemistry and immunohistochemistry. In normal left ventricular myocardium, DGKalpha, DGKepsilon, and DGKzeta mRNAs were expressed evenly throughout the myocardium, although the DGKalpha expression was very low. In infarcted hearts, the expression of DGKzeta was enhanced in the peripheral zone of the necrotic area and at the border zone 3 and 7 days after MI, and to a lesser extent in the middle layer of the granulation tissue 21 days after MI. The enhanced DGKzeta expression in the infarcted and border areas could be attributed to granulocytes and macrophages. In contrast, the expression of DGKepsilon in the infarcted and border areas was lower than that in the viable left ventricle (LV) throughout the postoperation period. Furthermore, DGKepsilon expression in the viable myocardium 21 days after MI decreased significantly compared with left ventricular myocardium in the sham-operated rats and was completely restored by treatment with captopril. Our results demonstrate that three DGK isozymes are expressed in the heart and that each isozyme might have different functional characteristics in the healing and LV remodeling after MI.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Sweet's syndrome associated with encephalitis.

The involvement of the central nervous system (CNS) in Sweet's syndrome (acute febrile neutrophilic dermatosis) is rare. We report a 47-year-old woman who presented with acute encephalitis and was subsequently diagnosed as having Sweet's syndrome. She developed altered consciousness following fever and erythematous skin plaques in the extremities. Cerebrospinal fluid (CSF) examination disclosed neutrophilic pleocytosis without decreased glucose level. Brain magnetic resonance imaging (MRI) showed abnormal signal intensity lesions in the basal ganglia and the hippocampus. Skin biopsy revealed a dense dermal infiltration of neutrophils, which is compatible with Sweet's syndrome. Treatment with acyclovir and antibiotics failed, but the subsequent corticosteroid therapy was effective. Awareness of neurological complication in Sweet's syndrome may avoid unnecessary empiric therapy for meningoencephalitis and will lead to a successful treatment with corticosteroids.

Adrenal Cortex Hormones↗
PubMed2001

Combined treatment with specific ligands for PPARgamma:RXR nuclear receptor system markedly inhibits the expression of cytochrome P450arom in human granulosa cancer cells.

Our previous study demonstrated that PPARgamma specific ligand troglitazone (TGZ) or RXR specific ligand LG100268 (LG) alone decreased the aromatase activity in cultured human ovarian granulosa cells from pre-ovulatory follicles, and combined treatment caused an even greater reduction in this activity. Since similar manners of effects of TGZ or/and LG on the aromatase activity in human ovarian granulosa cancer cell line were observed, we performed the detailed analysis of the mechanisms of these effects using this cell line. The changes in the aromatase activity were associated with comparable changes in the P450arom mRNA levels based on a RNase protection assay. A nuclear run-on assay indicated the P450arom transcript to decrease by 40 and 66% at 24 and 48 h, respectively, after TGZ plus LG treatment. An RNA stability analysis showed the half-life of P450arom mRNA to decrease from 13 to 9 h after the TGZ plus LG treatment. The inhibitory effect of TGZ plus LG on the aromatase activity and P450arom mRNA may not be mediated by the cAMP-PKA pathway that is usually implicated in the regulation of aromatase activity in granulosa cells: because (1) the aromatase activity stimulated by forskolin was not inhibited by TGZ plus LG; (2) the specific PKA inhibitor H89 could not block the inhibitory effect of TGZ plus LG on the aromatase activity; and (3) the luciferase activity of P450arom promoter II did not decrease by the addition of TGZ and LG in transfected cells either at a basic state or in the states stimulated by forskolin or PGE2, respectively. Taken together, these results indicate that TGZ plus LG inhibited the aromatase activity and also decreased the P450arom mRNA level in granulosa cancer cells, and the loss of P450arom mRNA expression was considered to be due to both the decreased transcription and rapid degradation of its RNA.

Aromatase↗
PubMed2001

The subnuclear three-dimensional image analysis of androgen receptor fused to green fluorescence protein.

To establish the novel approach in order to distinguish the transcriptionally active androgen receptor (AR) from the transcriptionally inactive AR, we performed the three-dimensional construction of confocal microscopic images of intranuclear AR. This method clearly distinguished the subnuclear localization of transcriptionally active AR tagged with green fluorescent protein (AR-GFP) from the transcriptionally inactive AR-GFP. Transcriptionally active AR-GFP mainly produced 250-400 fluorescence foci in the boundary region between euchromatin and heterochromatin. Although the AR-GFP bound to such antiandrogens as hydroxyflutamide or bicalutamide translocated to the nucleus, they homogeneously spread throughout the nucleus without producing any fluorescence foci. Antiandrogenic environmental disrupting chemicals, such as 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene, vinclozolin, or nitrofen, also disrupted the intranuclear fluorescence foci. A point mutation (T877A) resulted in the loss of ligand specificity in AR-GFP. Even in this mutant receptor, agonists, such as dihydrotestosterone, hydroxyflutamide, or progesterone, produced the fluorescence foci in the nucleus, whereas the transcriptionally inactive mutant binding bicalutamide was observed to be spread homogeneously in the nucleus. Taken together, our findings suggest that, after nuclear translocation, AR is possibly located in the specific region in the nucleus while demonstrating clustering tightly depending on the agonist-induced transactivation competence.

Active Transport, Cell Nucleus↗
PubMed2001

Novel molecular mechanism of increased myocardial endothelin-1 expression in the failing heart involving the transcriptional factor hypoxia-inducible factor-1alpha induced for impaired myocardial energy metabolism.

BACKGROUND: Hypoxia-inducible factor (HIF)-1alpha is an important transcriptional factor that activates the gene expression of glycolytic enzymes, which are activated as compensation for impaired beta-oxidation of fatty acid in the failing heart. We reported that cardiac endothelin (ET)-1 expression is markedly increased in heart failure. The mechanism, however, is unknown. Because we found an HIF-1alpha binding site in the 5'-promoter region of the ET-1 gene, we hypothesized that HIF-1alpha is involved in this mechanism. METHODS AND RESULTS: In rat cardiomyocytes, luciferase assay and electrophoretic mobility shift assay showed that HIF-1alpha transcriptionally activates ET-1 gene expression by direct interaction with the predicted DNA binding site in the 5'-promoter region. HIF-1alpha mRNA and ET-1 mRNA in the failing heart increased during the aggravation of heart failure in vivo in animal models, ie, rats with myocardial infarction and hamsters with cardiomyopathy. In cultured cardiomyocytes treated with a mitochondrial inhibitor, HIF-1alpha mRNA and ET-1 mRNA were markedly increased with activated glycolysis, and antisense oligonucleotide for HIF-1alpha largely inhibited the increased gene expression of ET-1. CONCLUSIONS: The present study revealed a novel molecular mechanism of upregulation of myocardial ET-1 in heart failure, indicating that induction of HIF-1alpha to stimulate glycolysis as an adaptation in heart failure against impaired energy metabolism alternatively causes an elevation of cardiac ET-1 gene expression as a maladaptation.

Adenosine Triphosphate↗
PubMed2001

Glia-synapse interaction through Ca2+-permeable AMPA receptors in Bergmann glia.

Glial cells express a variety of neurotransmitter receptors. Notably, Bergmann glial cells in the cerebellum have Ca2+-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) assembled without the GluR2 subunit. To elucidate the role of these Ca2+-permeable AMPARs, we converted them into Ca2+-impermeable receptors by adenoviral-mediated delivery of the GluR2 gene. This conversion retracted the glial processes ensheathing synapses on Purkinje cell dendritic spines and retarded the removal of synaptically released glutamate. Furthermore, it caused multiple innervation of Purkinje cells by the climbing fibers. Thus, the glial Ca2+-permeable AMPARs are indispensable for proper structural and functional relations between Bergmann glia and glutamatergic synapses.

Adenoviridae↗
PubMed2001

Detection of Salmonella enteritidis in shell and liquid eggs using enrichment and plating.

Detection methods using various enrichment and plating media and immunoconcentration for Salmonella enteritidis in shell and liquid eggs were evaluated. For liquid egg samples naturally contaminated with S. enteritidis, pre-enrichment in 225 ml of buffered peptone water with cysteine followed by selective enrichment in 10 ml of tetrathionate broth was the superior, resulting in the detection of S. enteritidis in all samples on six of the seven types of selective agar substrate investigated. This enrichment procedure also enabled detection of S. enteritidis in most of artificially inoculated shell egg and pasteurized liquid egg samples.

Animals↗
PubMed2001

Phenotypic variation in a large Japanese family with Miyoshi myopathy with nonsense mutation in exon 19 of dysferlin gene.

Miyoshi myopathy, an autosomal recessive muscular dystrophy involving distal muscles, is caused by dysferlin mutations. We present clinical and genetic studies of two men and six women, aged 25-83 years, from a Japanese family with consanguineous marriages. Onset was between ages 17 and 59 years. Six of the patients had muscle involvement typical of Miyoshi myopathy, one initially had severe proximal muscle involvement, and one had scapuloperoneal-type muscle involvement. Three patients showed steppage gait. Genetic linkage analysis identified a maximum lod score of 3.34 (θ=0.00) at marker D2S292 in 2p13. Analysis of dysferlin revealed the mutation G2090T (Glu573Stop) in exon 19 in all affected patients. This is the largest Japanese family with Miyoshi myopathy showing intrafamilial phenotypic variation and sharing a common mutation in dysferlin.

Adult↗
PubMed2001

Oxygen radicals mediate the final exacerbation of endothelin-1-induced gastric ulcer in rat.

We investigated the role of xanthine oxidase-derived oxygen radicals in the development of endothelin-1-induced gastric ulcer. Mucosal lipid peroxidation showed a peak 24 h after injection, while gastric mucosal haemodynamics were fully restored 26 h after endothelin-1 injection. Allopurinol and oxypurinol, but not superoxide dismutase or catalase, protected the gastric mucosa 24 h after endothelin-1 injection. Oxypurinol antagonized both the vasoconstrictor effect of endothelin-1 and the decrease in gastric ATP. All treatments on the second day after endothelin-1 injection significantly reduced gastric mucosal damage. Xanthine oxidase-derived oxygen radicals contributed largely to the exacerbation but they did not mediate the onset of endothelin-1-induced gastric ulcer. Pretreatment with probucol (500 mg/kg, p.o.) also protected the gastric mucosa from endothelin-1-induced mucosal injury by its antioxidant activity. Oxypurinol was gastroprotective through its vasoactive and energy saving actions. The haemodynamic background of endothelin-1-induced gastric ulcer consists of long lasting ischaemia and subsequent "reperfusion" which may be responsible for the late burst of oxygen radicals.

Adenosine Triphosphate↗
PubMed2001

Complexes of MADS-box proteins are sufficient to convert leaves into floral organs.

Genetic studies, using floral homeotic mutants, have led to the ABC model of flower development. This model proposes that the combinatorial action of three sets of genes, the A, B and C function genes, specify the four floral organs (sepals, petals, stamens and carpels) in the concentric floral whorls. However, attempts to convert vegetative organs into floral organs by altering the expression of ABC genes have been unsuccessful. Here we show that the class B proteins of Arabidopsis, PISTILLATA (PI) and APETALA3 (AP3), interact with APETALA1 (AP1, a class A protein) and SEPALLATA3 (SEP3, previously AGL9), and with AGAMOUS (AG, a class C protein) through SEP3. We also show that vegetative leaves of triply transgenic plants, 35S::PI;35S::AP3;35S::AP1 or 35S::PI;35S::AP3;35S::SEP3, are transformed into petaloid organs and that those of 35S::PI;35S::AP3;35S::SEP3;35S::AG are transformed into staminoid organs. Our findings indicate that the formation of ternary and quaternary complexes of ABC proteins may be the molecular basis of the ABC model, and that the flower-specific expression of SEP3 restricts the action of the ABC genes to the flower.

Arabidopsis↗
PubMed2001

The anxiolytic effect of Sho-ju-sen, a Japanese herbal medicine, assessed by an elevated plus-maze test in mice.

Sho-ju-sen (SK), a Japanese herbal medicine with a nourishing tonic action, is composed of a water extract of Kumazasa leaves (Sasa kurinensis Makino et Sibata) (SS), and ethanol extracts of Japanese red pine needles (Pinus densiflora Sieb. et Zucc) (PN) and Ginseng roots (Panax ginseng C. A. Meyer) (PX) in the ratio 8:1:1. In this study, an elevated plus-maze test in mice was carried out to assess whether SK had an anxiolytic effect. No significant change was observed in either the plus-maze or activity test following a single administration of SK (10 and 20 mL/kg p.o.). However, mice allowed a free intake of SK (10% solution) for 5 days and longer showed a significant prolongation of the time spent in the open arms (an anxiolytic effect), as long as that caused by the benzodiazepine anxiolytic diazepam (1 mg/kg p.o.). SK (1%, 3% and 30% solutions for 7 days) tended to develop the anxiolytic effect. Of the constituents of SK, SS (8% solution), but not PN (1% solution) or PX (1% solution), resulted in the anxiolytic effect. Except for a slight acceleration in the motor activity by PN (1% solution), no significant change in the motor activity was produced by any treatment with SK, SS or PX. The combined treatment of SK (10% solution) or SS (8% solution) with 1 mg/kg diazepam enhanced the anxiolytic effect. Flumazenil (0.1 mg/kg s.c.), a benzodiazepine receptor antagonist, alone did not change the time spent in the open arms. However, it completely reversed the anxiolytic effect of SK, SS and diazepam. The present results suggest that: (1) long-term treatment with SK develops an anxiolytic effect, (2) SS is the main constituent for the anxiolytic effect of SK, and (3) benzodiazepine receptors are involved in the anxiolytic effect of SK and SS.

Animals↗
PubMed2001

Task-dependent strain difference of spatial learning in C57BL/6N and BALB/c mice.

In the present study, we used a dry maze task to assess the spatial learning ability of C57BL/6N and BALB/cA mice besides the water maze task. In Experiment 1, the performance of C57BL/6N and BALB/cA mice in the water maze task and dry maze task were investigated. In the former task, the mice had to learn the position of a hidden platform submerged below the water surface and they had to learn the position of a baited hole on the circular maze in the latter task. C57BL/6N mice showed significant learning in both maze tasks, whereas BALB/cA mice showed learning in a dry maze but not in water maze as reported before. In Experiment 2, a dry maze task was conducted on a circular open field which contained 16 holes arranged symmetrically and which was put on the same height as the surface of the water maze. In Experiment 2, BALB/cA mice showed significant improvement in latency and path length to reach the food hole. The poor performance of the BALB/cA in the water maze task may reflect a weak motivation, escaping from water, rather than the poor spatial memory in this strain.

Animals↗
PubMed2001

Highly diverse TTV population in infants and their mothers.

Infants born to serum HCV-positive 12 mothers were enrolled in the study. Nucleotide sequences amplified by primers deduced from a noncoding region were compared between mothers and their infants. The rates for detection of serum TTV in 12 mothers and their infants were 10/12 (83%) and 9/12 (75%), respectively. Serum TTV DNA was not detected in any infant at 1 month of age, but was detected for the first time between 1.5 and 8 months after birth. Positivity persisted thereafter throughout the follow-up period. In seven randomly selected mother-infant pairs, intrahost TTV heterogeneity was lower in infants than in mothers. Furthermore, one of seven mother-infant pairs showed a high degree of similarity (98.7-100%) in all clones, while in four infants, all nucleotide sequences differed by >10% from those of their mothers. However, the degree of homology in the two mother-infant pairs was 89-98.7% in family 2 and 88.1-99.4% in family 5. In the present study, with only one exception, it was shown that TTV from infants is not identical to TTV from mothers. The mechanism is discussed briefly in this paper.

DNA Virus Infections↗
PubMed2001

Serum levels of KL-6 are useful biomarkers for severe radiation pneumonitis.

The antigen KL-6, a mucin-like high-molecular-weight glycoprotein, is expressed on type-2 pneumocytes and bronchiolar epithelial cells. Serum levels of KL-6 have been shown to correlate well with the activities of several different kinds of interstitial pneumonia. The purpose of this study was to assess the usefulness of monitoring serum KL-6 levels in patients who had received thoracic radiotherapy (TRT). In particular, the usefulness of such a protocol for the early diagnosis of severe radiation pneumonitis (RP) and the evaluation of its progress and severity was examined. Serum KL-6 levels were retrospectively monitored in 16 patients with lung cancer who had received TRT with or without chemotherapy. Eight of these patients had developed severe RP and eight had developed localized (within the irradiated field) RP. Serum KL-6 levels were measured using a modified sandwich-type enzyme-linked immunosorbent assay. In patients who developed severe RP, serum KL-6 levels showed a consistent tendency to increase after the clinical diagnosis of RP. In four patients, serum KL-6 levels even began to rise before a clinical diagnosis of severe RP had been made. In the patients with localized RP, on the other hand, the serum levels did not show any tendency to increase during or after TRT. Moreover, patients whose serum KL-6 levels rose more than 1.5 times higher than their pre-treatment serum KL-6 level, had a large chance of developing severe RP that was unresponsive to steroid hormones and resulted in death. Serum KL-6 levels, therefore, should be useful indicators for the early diagnosis of severe RP and for estimating its progress and severity in patients treated with TRT.

Aged↗
PubMed2001

Microsatellite mapping of a susceptible locus within the HLA region for Behçet's disease using Jordanian patients.

Behçet's disease (BD) has been established to be associated with HLA-B51. However, it has not been revealed whether the HLA-B51 gene itself or another gene located near the HLA-B gene is directly involved in the pathogenesis of BD. Previously, using Japanese BD patients, our group has narrowed down a BD-causative gene to 46 kb between the MICA and HLA-B genes by means of fine mapping analysis with eight microsatellite markers distributed within a 1100 kb segment around the HLA-B gene. To know whether this mapping result is generally observed in BD of another population we have investigated repeat polymorphisms of the same microsatellite markers in Jordanian BD patients. Furthermore, we have evaluated these data by Mantel-Haenzel stratified analysis to find out a primarily associated locus for BD. As a result, HLA-B51 was found to be the most strongly and primarily associated marker. This result suggests that the pathogenic gene of BD is HLA-B51 itself, but unlikely to be other genes located in the vicinity of HLA-B.

Adolescent↗
PubMed2001

Spatial and temporal gene expression in chondrogenesis during fracture healing and the effects of basic fibroblast growth factor.

Chondrogenesis is an essential component of endochondral fracture healing, though the molecular and cellular events by which it is regulated have not been fully elucidated. In this study, we used a rat model of closed fracture healing to determine the spatial and temporal expression of genes for cartilage-specific collagens. Furthermore, to determine the effects of basic fibroblast growth factor (bFGF) on chondrogenesis in fracture healing, we injected 100 microg recombinant human bFGF into the fracture site immediately after fracture. In normal calluses, pro-alpha1(II) collagen mRNA (COL2A1) was detected in proliferative chondrocytes beginning on day 4 after the fracture, and pro-alpha1(X) collagen mRNA (COL10A1) in hypertrophic chondrocytes beginning on day 7. In FGF-injected calluses, the cartilage enlarged in size significantly. On day 14, both COL2A1- and COL10A1-expressing cells were more widely distributed, and the amounts of COL2A1 and COL10A1 mRNAs were both approximately 2-fold increased when compared with uninjected fractures. Temporal patterns of expression for these genes were, however, identical to those found in normal calluses. The number of proliferating cell nuclear antigen-positive cells was increased in the non-cartilaginous area in the bFGF-injected calluses by day 4. The present molecular analyses demonstrate that a single injection of bFGF enhances the proliferation of chondroprogenitor cells in fracture callus, and thus contributes to the formation of a larger cartilage. However, maturation of chondrocytes and replacement of the cartilage by osseous tissue are not enhanced by exogenous bFGF, and this results in the prolonged cartilaginous callus phase. We conclude that, in the healing of closed fractures of long bones, exogenous bFGF has a capacity to enlarge the cartilaginous calluses, but not to induce more rapid healing.

Animals↗
PubMed2001

Genetic ablation of orexin neurons in mice results in narcolepsy, hypophagia, and obesity.

Orexins (hypocretins) are a pair of neuropeptides implicated in energy homeostasis and arousal. Recent reports suggest that loss of orexin-containing neurons occurs in human patients with narcolepsy. We generated transgenic mice in which orexin-containing neurons are ablated by orexinergic-specific expression of a truncated Machado-Joseph disease gene product (ataxin-3) with an expanded polyglutamine stretch. These mice showed a phenotype strikingly similar to human narcolepsy, including behavioral arrests, premature entry into rapid eye movement (REM) sleep, poorly consolidated sleep patterns, and a late-onset obesity, despite eating less than nontransgenic littermates. These results provide evidence that orexin-containing neurons play important roles in regulating vigilance states and energy homeostasis. Orexin/ataxin-3 mice provide a valuable model for studying the pathophysiology and treatment of narcolepsy.

Animals↗