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Biomedical subjects

K Hashimoto

Publications and source records attributed to K Hashimoto.

At least 469 records · Page 26Linked to original sources
PubMed1999

[An experience of indwelling of a urethral stent (Urolume Wallstent) for urethral stricture accompanying pelvic fracture in a young man].

The patient was a 15-year-old boy, who sustained pelvic fracture and complete disruption of the urethra in a traffic accident. The previous doctor performed two-staged treatment for complete disruption of the urethra, which ended in postoperative urethral stricture. We performed two sessions of endoscopic operations and a pull-through procedure, but the procedures were not effective. Five years later, a urethral stent was indwelt. Urolume Wallstent of AMS, Co, Ltd. was used as the urethral stent. At 4 months, the stent started to be enveloped in the urethral epithelia and no complications have been found in particular. However, detention of a permanent-type stent in a young man such as ours remains a controversial issue and long-term follow-up is needed.

Accidents, Traffic↗
PubMed1999

[The significance of color duplex ultrasonography for the diagnosis of temporal arteritis].

We examined the usefulness of color duplex ultrasonography in patients suspected of having temporal arteritis. Five patients, who were all aged 70 or older, developed a new onset of localized headache with temporal artery abnormalities, and had an elevated erythrocyte sedimentation rate of > 100 mm/hour. The final diagnoses were temporal arteritis in three patients, polymyalgia rheumatica in one, and probable healed temporal arteritis in one. Color duplex ultrasonography showed stenoses, which were confirmed histologically as well, in the superficial temporal artery of all patients. The characteristic findings of active temporal arteritis were, however, demonstrated in only three biopsy specimens, and in the remaining two the stenoses were thought to be related to previous arteritis. The hypoechoic halo, which has been reported to be a characteristic finding of color duplex ultrasonography in active temporal arteritis, was detected in only one patient with active temporal arteritis and another one with probable healed temporal arteritis. No stenoses were demonstrated in the superficial temporal arteries of 30 control subjects (20 with at least one risk factor of atherosclerosis and 10 without it). Color duplex ultrasonography can therefore be considered a powerful method for detecting stenoses in the superficial temporal artery. Its ability to identify their etiology is, however, unsatisfactory, so that temporal artery biopsy remains undoubtedly the most reliable test for etiological evaluation. We thus recommend color duplex ultrasonography as a supplementary method for the diagnosis of temporal arteritis, because it can provide useful information concerning the appropriate site of temporal artery biopsy.

Aged↗
PubMed1999

Congenital ichthyosiform erythroderma: particulate staining pattern of TGK.

A case of late onset non-bullous congenital ichthyosiform erythroderma (CIE) was studied. This patient was not born as a collodion baby and did not have skin abnormalities until 9-10 years of age. She gradually developed erythroderma and fine scales, callosities of her feet, and a mild ectropion. Since recent work has revealed that in the majority of CIE patients, transglutaminase (TGK) is distributed in the cytoplasm of granular cells and horny cells (11), TGK was studied in our case. It was found that TGK was distributed along the cell periphery of horny cells and also in the cytoplasm of granular cells. In the control skins, TGK was stained along the cell periphery of horny cells and granular cells. The marginal band formation was normal. Involucrine and loricrin, the building materials of the marginal band whose-cross-linking is mediated by TGK, were normally stained in the upper epidermis. Cytoplasmic TGK of granular cells and normal development of the marginal band may serve as a helpful diagnostic marker of CIE, particularly because the often confusing collodion baby of lamellar ichthyosis may lack TGK staining and the marginal band altogether.

Age of Onset↗
PubMed1999

[An autopsy case of interstitial pneumonia probably induced by Sho-saiko-to].

A 66-year-old woman had been treated for 3 years by her local physician with Sho-saiko-to for chronic hepatitis C virus (HCV) infection and liver cirrhosis. She was admitted to our hospital because of cough, fever, and infiltrative shadows on chest x-ray films. Sho-saiko-to-induced pneumonitis was diagnosed and steroid therapy started. Though a temporary improvement was observed, interstitial pneumonitis relapsed and the patient died of respiratory failure and liver dysfunction. Autopsy findings showed diffuse alveolar damage and honeycombing. Furthermore, reverse-transcriptase polymerase chain reaction techniques detected HCV-RNA in specimens of fibrotic lung tissue. For comparison, HCV-RNA was not histologically detected in lung tissue specimens from 4 control subjects who were positive for HCV antibodies but who did not have interstitial lung disease. It was speculated that the progression of interstitial pneumonia in the present case may have been caused by HCV in combination with Sho-saiko-to-induced lung injury.

Aged↗
PubMed1999

What are the predictors of restoration of sinus rhythm after combined treatment with surgical repair for organic heart disease and the Maze procedure for atrial fibrillation?

BACKGROUND: Recently, combined treatment using the Maze procedure for organic heart disease and atrial fibrillation has been reported, but there have been few studies of cardiac rhythm after combined treatment. Predictors of cardiac rhythm after combined surgical treatment have been unknown. METHODS: Thirty patients who underwent cardiac surgery with the Maze procedure were retrospectively enrolled in this study. Two groups consisted of the patients with restoration of sinus rhythm after surgery (SR: n=15, 6 males and 9 females, mean age of 64 years), and the patients with maintenance of atrial fibrillation (AF; n=15, 5 males and 10 females, mean age of 61 years). Before cardiac surgery, all patients underwent exercise testing with measurement of atrial natriuretic peptide (ANP) before and after exercise testing, two-dimensional echocardiography, and right and left heart catheterization. RESULTS: The mean maximal heart rate and the ANP level after exercise testing in SR were significantly higher than those in AF. The left atrial dimension and right atrial and pulmonary capillary wedge pressures were significantly higher in AF than in SR. These findings indicate that subjects in SR exhibited less impaired atrial function which were evaluated by exercise testing with measurement of ANP, echocardiography, and cardiac catheterization. CONCLUSIONS: The atrial function of patients with sinus rhythm after the Maze procedure may be less impaired than that of patients remaining in atrial fibrillation.

Aged↗
PubMed1998

Phospholipase cbeta4 is specifically involved in climbing fiber synapse elimination in the developing cerebellum.

Elimination of excess climbing fiber (CF)-Purkinje cell synapses during cerebellar development involves a signaling pathway that includes type 1 metabotropic glutamate receptor, Galphaq, and the gamma isoform of protein kinase C. To identify phospholipase C (PLC) isoforms involved in this process, we generated mice deficient in PLCbeta4, one of two major isoforms expressed in Purkinje cells. PLCbeta4 mutant mice are viable but exhibit locomotor ataxia. Their cerebellar histology, parallel fiber synapse formation, and basic electrophysiology appear normal. However, developmental elimination of multiple CF innervation clearly is impaired in the rostral portion of the cerebellar vermis, in which PLCbeta4 mRNA is predominantly expressed. By contrast, CF synapse elimination is normal in the caudal cerebellum, in which low levels of PLCbeta4 mRNA but reciprocally high levels of PLCbeta3 mRNA are found. These results indicate that PLCbeta4 transduces signals that are required for CF synapse elimination in the rostral cerebellum.

Animals↗
PubMed1998

Effect of oral administration of Pinellia ternata, Zingiberis rhizoma and their mixture on the efferent activity of the gastric branch of the vagus nerve in the rat.

The effect of taste stimulation of Pinellia temata, Zingiberis rhizoma and their mixture on the efferent activity of the gastric branch of the vagus nerve was observed in the anesthetized rat. Taste stimulation by Pinellia ternata (50 mg/ml, 10 min) resulted in a suppression in vagal gastric nerve activity. On the contrary, stimulation by Zingiberis rhizoma (50 mg/ml, 10 min) caused a facilitation in efferent activity. The mixture of Pinellia ternata and Zingiberis rhizoma (5:1, 50 mg/ml, 10 min stimulation) demonstrated no suppressive effect on gastric nerve activity. These observations indicate that it is reasonable to prescribe Pinellia ternata with Zingiberis rhizoma in traditional Japanese medicine to prevent suppressive effect of the taste of Pinellia ternata on gastric function.

Administration, Oral↗
PubMed1998

Suppression of electrophoretic anomaly of bent DNA segments by the structural property that causes rapid migration.

Intrinsic DNA curvature is speculated to be a common feature of all satellite DNA sequences and may aid in the tight winding of DNA in constitutive heterochromatin. Several satellite DNAs, however, show unusually rapid migration in non-denaturing polyacrylamide gels, which is just the opposite behavior of that shown by curved DNA structures. Employing bovine satellite I DNA monomer, we attempted to understand the molecular mechanism of 'rapid migration'. The phenomenon of rapid migration was temperature-dependent and to a small extent polyacrylamide-concentration-dependent. Physiological or near-physiological concentrations of Mg2+and Ca2+ions bent the rapid migrating DNA segment. Predominance of purine-purine base stacking over purine-pyrimidine in nucleotide sequence was strongly indicated to be the cause of the rapid migration. Furthermore, they seemed to be implicated in the formation of induced DNA bend. We also found that the satellite I monomer contains an intrinsic DNA curvature as do many other satellites. Heretofore, the rapid migration property has concealed the presence of curvature.

Animals↗
PubMed1998

Effect of chronic haloperidol treatment on synaptic protein mRNAs in the rat brain.

Chronic haloperidol treatment caused significant decreases in the levels of synaptotagmin I and IV, synaptobrevin II, syntaxin 1A and Rab 3A mRNAs in the nucleus accumbens but not in the prefrontal cortex medial field, striatum, substantia nigra and ventral tegmental area. No significant changes in SNAP 25 and synaptophysin mRNA levels were observed in any brain region examined. The reduced expression of synaptic proteins may be related to haloperidol-induced depolarization block of mesolimbic dopamine neurons.

Animals↗
PubMed1998

Collagen abnormalities in the spinal cord from patients with amyotrophic lateral sclerosis.

During the last 10 years, we have demonstrated morphological and biochemical abnormalities of skin extracellular matrices in amyotrophic lateral sclerosis (ALS). However, currently little is known concerning collagen of the spinal cord in ALS. We measured the amount of collagen and characterized collagen at light and electron microscopic levels in posterior funiculus, posterior half of lateral funiculus and anterior horn of cervical enlargement of the spinal cord obtained from ten patients with ALS, 11 patients with other neurologic diseases (control group A), and ten patients without neurologic ones (control group B). In posterior half of lateral funiculus and anterior horn, (1) by light microscopy, there was no significant difference in vessel wall area between ALS patients and control groups A and B; (2) ultrastructurally, collagen bundles were more fragmented and widely separated, and the fibrils were randomly oriented in the perivascular space of capillaries in ALS patients, which were not observed in any areas of control groups or in posterior funiculus of ALS patients; and (3) the collagen contents in ALS were significantly lower (P<0.001 and P<0.001, respectively) than those in control groups A and B. Fragmented and widely separated collagen bundles in the interstitial tissue surrounding capillaries and markedly decreased amount of collagen in posterior half of lateral funiculus and in anterior horn of ALS could be related to the degeneration of the upper and lower motor neurons in the spinal cord in ALS, that is, selective neuronal vulnerability in ALS.

Adult↗
PubMed1998

Ablation of cerebellar Golgi cells disrupts synaptic integration involving GABA inhibition and NMDA receptor activation in motor coordination.

The role of inhibitory Golgi cells in cerebellar function was investigated by selectively ablating Golgi cells expressing human interleukin-2 receptor alpha subunit in transgenic mice, using the immunotoxin-mediated cell targeting technique. Golgi cell disruption caused severe acute motor disorders. These mice showed gradual recovery but retained a continuing inability to perform compound movements. Optical and electrical recordings combined with immunocytological analysis indicated that elimination of Golgi cells not only reduces GABA-mediated inhibition but also attenuates functional NMDA receptors in granule cells. These results demonstrate that synaptic integration involving both GABA inhibition and NMDA receptor activation is essential for compound motor coordination. Furthermore, this integration can adapt after Golgi cell elimination so as not to evoke overexcitation by the reduction of NMDA receptors.

Animals↗
PubMed1998

Expanded genomic organization of conserved mammalian MHC class I-related genes, human MR1 and its murine ortholog.

MR1 is a major histocompatibility complex (MHC) class I-related gene located outside the human MHC. Among several divergent class I molecules, the predicted MR1 molecule is closest, in the alpha1 and alpha2 domains, to the class I group to which the vertebrate classical class I molecules belong. We report here the genomic organizations of the human MR1 and mouse Mr1 genes. Both genes exhibit genomic structures largely similar to those of the MHC class I genes. However, they are highly expanded in their scale in contrast to the classical MHC class I genes. Inclusion of transposable elements into introns seems to partly contribute to these genomic structures. Several other MHC class I-related genes also show relatively large genomic structures. The present study extended heterogeneity in the genomic organization among the class I gene family by revealing a highly expanded structure of the human MR1 gene and its murine ortholog.

Amino Acid Sequence↗
PubMed1998

Effect of urocortin on ACTH secretion from rat anterior pituitary in vitro and in vivo: comparison with corticotropin-releasing hormone.

Both urocortin (UCN) and corticotropin-releasing hormone (CRH) are known to stimulate secretion of adrenocorticotropic hormone (ACTH) by corticotroph cells via type-1 corticotropin-releasing hormone receptor (CRHR-1). We extensively examined UCN effects on the anterior pituitary (AP), particularly on proopiomelanocortin (POMC) mRNA and CRHR-1 mRNA as well as ACTH secretion in vivo. Moreover, signal transduction with UCN exposure was assessed in AP cell cultures in comparison with transduction following CRH exposure. Intravenously administered of UCN (5 microg/kg) increased ACTH and corticosterone secretion. Similarly, intravenous administration of UCN increased POMC mRNA and decreased CRHR-1 mRNA in the AP. These UCN effects were more potent and long-lasting than those of CRH. The prominent effect of UCN on ACTH secretion in vivo was confirmed in AP cell cultures, where application of UCN stimulated ACTH release approximately 7 times more strongly than CRH. The effect of UCN on ACTH release was enhanced by phorbol esters which activate protein kinase C, but was reduced by the selective cAMP-dependent protein kinase inhibitor, H-89. These results suggest that, as with CRH, UCN stimulates ACTH production and/or release through cAMP-dependent mechanisms, and that protein kinase C-dependent mechanism has a synergistic effect upon UCN-induced ACTH release. The more potent effects of UCN relative to CRH may be attributable to UCN's higher affinity for CRHR-1.

Adrenocorticotropic Hormone↗
PubMed1998

Impaired expression of integrin alpha-4 subunit in cultured mast cells derived from mutant mice of mi/mi genotype.

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). We have reported that expression of several genes was impaired in cultured mast cells (CMCs) of mi/mi mice due to a defective transactivation ability of mutant MITF (mi-MITF). Because attachment of mi/mi CMCs to fibroblasts is impaired, we examined the expression of integrin genes in mi/mi CMCs in the present study. Among the integrin genes examined, the expression of integrin alpha4 subunit was barely detectable in mi/mi CMCs, and the alpha4 protein was not detected by flow cytometry either. The specific adhesion to vascular cell adhesion molecule-1 (VCAM-1), the ligand for alpha4 subunit, was observed in +/+ CMCs but not in mi/mi CMCs, indicating that the expression of integrin alpha4 subunit at a functional level did not occur in mi/mi CMCs. In the promoter region of the alpha4 subunit gene, there was a CACTTG motif to which normal MITF (+- MITF) bound. The coexpression of +-MITF but not of mi-MITF transactivated the promoter of the alpha4 subunit gene. The deletion or mutation of the CACTTG motif abolished the transactivation by +-MITF, suggesting that +-MITF directly transactivated the gene encoding alpha4 subunit of integrin.

Animals↗
PubMed1998

Behavioral changes and expression of heat shock protein hsp-70 mRNA, brain-derived neurotrophic factor mRNA, and cyclooxygenase-2 mRNA in rat brain following seizures induced by systemic administration of kainic acid.

Kainic acid-induced seizures in rats represent an established animal model for human temporal lobe epilepsy. However, it is well-known that behavioral responses to the systemic administration of kainic acid are inconsistent between animals. In this study, we examined the relationship between expression of genes, neuropathological damage, and behavioral changes (seizure intensity and body temperature) in rats after systemic administration of kainic acid. The considerable differences in the response to kainic acid-induced seizures were observed in rats after a single administration of kainic acid (12 mg/kg i.p.). There was no detection of the expression of heat shock protein hsp-70 mRNA and HSP-70 protein in brain of vehicle-treated controls and in animals exhibiting weak behavioral changes (stage 1-2). A moderate expression of hsp-70 mRNA was detected throughout all regions (the pyramidal cell layers of CA1-3 and dentate gyrus) of the hippocampus, the basolateral, lateral, central and medial amygdala, the piriform cortex, and the central medial thalamic nucleus of rats that developed moderate seizures (stage 3-4). Marked expression of hsp-70 mRNA was detected in the all regions (cingulate, parietal, somatosensory, insular, entorhinal, piriform cortices) of cerebral cortex and all regions of hippocampus, and the central medial thalamic nucleus of the rats that developed severe seizures (stage 4-5). In addition, marked HSP-70 immunoreactivity was detected in the pyramidal cell layers of CA1 and CA3 regions of hippocampus, all regions (cingulate, parietal, somatosensory, insular, piriform cortices) of cerebral cortex, and the striatum of rats that developed severe seizures (stage 4-5). Furthermore, a marked expression of cyclooxygenase-2 (COX-2) mRNA and brain-derived neurotrophic factor (BDNF) mRNA levels by kainic acid-induced behavioral seizures (stage 3-4 or stage 4-5) was detected in all hippocampal pyramidal cell layers, granule layers of dentate gyrus, piriform cortex, neocortex, and amygdala. The present study suggest that the behavioral changes (seizure intensity and body temperature) and neuropathological damage after systemic administration of kainic acid are inconsistent between animals, and that these behavioral changes (severity of kainic acid-induced limbic seizures) might be correlated with gene expression of hsp-70 mRNA, COX-2 mRNA, and BDNF mRNA in rat brain.

Animals↗
PubMed1998

Insulin-like growth factor-I augments erythropoietin-induced proliferation through enhanced tyrosine phosphorylation of STAT5.

Insulin-like growth factor (IGF-I) is known to synergistically stimulate the proliferation of hematopoietic cells in combination with other hematopoietic growth factors. However, the precise mechanism underlying the cooperative effects of IGF-I is unknown. In a human interleukin-3 or erythropoietin (EPO)-dependent cell line, F-36P, IGF-I alone failed to stimulate DNA synthesis but did augment the EPO-dependent DNA synthesis of F-36P cells. The treatment of F-36P cells with a combination of EPO and IGF-I (EPO/IGF-I) was found to enhance EPO-induced tyrosine phosphorylation of STAT5, whereas IGF-I alone did not. Furthermore, c-CIS mRNA expression, one of the target molecules of STAT5, was more effectively induced by EPO/IGF-I than by EPO alone. To examine the mechanisms of the EPO- and EPO/IGF-I-induced proliferation of F-36P cells, we expressed dominant negative (dn) mutants of STAT5 and Ras in an inducible system. The EPO-induced DNA synthesis and the cooperative effect of EPO/IGF-I were significantly inhibited by the inducible expression of dn-STAT5 or dn-Ras. In addition, the inducible expression of dn-Ras abolished the IGF-I-enhanced tyrosine phosphorylation of STAT5. These results suggest that IGF-I may augment EPO-induced proliferation by enhancing tyrosine phosphorylation of STAT5 and raise the possibility that Ras may be involved in the augmentation of STAT5 tyrosyl phosphorylation.

Cell Division↗
PubMed1998

DNA polymerase II (epsilon) of Saccharomyces cerevisiae dissociates from the DNA template by sensing single-stranded DNA.

Two forms of DNA polymerase II (epsilon) of Saccharomyces cerevisiae, Pol II* and Pol II, were purified to near homogeneity from yeast cells. Pol II* is a four-subunit complex containing a 256-kDa catalytic polypeptide, whereas Pol II consists solely of a 145-kDa polypeptide derived from the N-terminal half of the 256-kDa polypeptide of Pol II*. We show that Pol II* and Pol II are indistinguishable with respect to the processivity and rate of DNA-chain elongation. The equilibrium dissociation constants of the complexes of Pol II* and Pol II with the DNA template showed that the stability of these complexes is almost the same. However, when the rates of dissociation of the Pol II* and Pol II from the DNA template were measured using single-stranded DNA as a trap for the dissociated polymerase, Pol II* dissociated 75-fold faster than Pol II. Furthermore, the rate of dissociation of Pol II* from the DNA template became faster as the concentration of the single-stranded DNA was increased. These results indicate that the rapid dissociation of Pol II* from the DNA template is actively promoted by single-stranded DNA. The dissociation of Pol II from the DNA template was also shown to be promoted by single-stranded DNA, although at a much slower rate. These results suggest that the site for sensing single-stranded DNA resides within the 145-kDa N-terminal portion of the catalytic subunit and that the efficiency for sensing single-stranded DNA by this site is positively modulated by either the C-terminal half of the catalytic subunit and/or the other subunits.

Amino Acid Sequence↗