Search PubMed⌕ Search

Biomedical subjects

M Hashimoto

Publications and source records attributed to M Hashimoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

Preventive effects of danazol on endometrial carcinogenesis in mice.

Short and long-term experiments were designed to determine effects of danazol on estrogen-related endometrial carcinogenesis in mice. The short-term assays showed that danazol decreased expression levels of c-fos/jun mRNA and their oncoproteins induced by estradiol-17beta (E2). For the long-term assay, 85 female ICR mice were given N-methyl-N-nitrsourea solution into their uterine corpora. The animals were divided into three groups as follows: Group 1, E2-diet (5 ppm) plus danazol (2 mg/body (s.c.), every 4 weeks); Group 2, E2-diet alone, Group 3, basal diet alone. At 30 weeks, incidences of atypical and complex endometrial hyperplasia were significantly decreased by danazol-treatment. These results suggest that danazol has preventive effects on estrogen-related endometrial carcinogenesis in mice, through the suppression of estrogen-induced c-fos/jun-expression.

Administration, Oral↗
PubMed2000

Corticosteroid-responsive diabetes mellitus associated with autoimmune pancreatitis.

Autoimmune pancreatitis, which can be treated with corticosteroid therapy, has the potential to induce diabetes. In a cohort study of 2220 patients with suspected chronic pancreatitis, we found that all four patients with autoimmune chronic pancreatitis also had diabetes. Treatment with prednisolone subsequently improved insulin secretion and glycaemic control in these patients.

Aged↗
PubMed2000

Structural significance of the acyl group at the C-10 position and the A ring of the taxane core of paclitaxel for inducing nitric oxide and tumor necrosis factor production by murine macrophages.

The antitumor agent, paclitaxel (Taxol), mimics the actions of lipopolysaccharide (LPS) on murine macrophages (Mphi). Various synthetic analogs of paclitaxel were examined for their potencies to induce nitric oxide (NO) and tumor necrosis factor (TNF) production by murine peritoneal Mphi, and by human peripheral blood cells. The benzoyl group at C-2, the hydroxy group at C-7 and the acetyl group at C-10 were found to be critically important sites to activate murine Mphi. Nor-seco-taxoid analogs lacking the A ring of the taxane core of paclitaxel were inactive, but inhibit paclitaxel- or LPS-induced NO production. All the compounds tested did not induce TNF production by human blood cells.

Acylation↗
PubMed2000

Dynamic changes of NADH fluorescence images and NADH content during spreading depression in the cerebral cortex of gerbils.

To elucidate the changes in the mitochondrial redox state during spreading depression (SD), tissue NADH content was measured in 20 anesthetized gerbils by the enzymatic cycling assay in a small cortical region (0.30+/-0.07 mg) where the direct-current (DC)-potential was measured. Sequential imaging of NADH fluorescence with a CCD camera and continuous monitoring of DC-potential and regional CBF were also performed in another 5 gerbils. Biphasic fluorescence waves propagating at the rate of 3 mm/min were observed using the CCD camera. An initial narrow (1.6+/-0.4 mm) wave, which showed a modest increase in fluorescence (108+/-6.4%), was observed simultaneously with the onset of negative DC-deflection. During depolarization, CBF was unchanged and tissue NADH content increased to 25.3+/-7.9 micromol/kg brain, which was higher than the value in the sham-control (11.0+/-2.5 micromol/kg brain). At 30 s after the deflection, a subsequent wide (7.0+/-2.1 mm) wave, which showed a moderate decrease in fluorescence (87.1+/-5.7%), was observed simultaneously with the increase in CBF and repolarization in DC-potential. Then NADH fluorescence recovered along with normalization of CBF at 152.2+/-38.6 s after the onset of DC-deflection. Tissue NADH concentration sampled at 120 s after the deflection was 11.6+/-4.6 micromol/kg brain. Since NADH fluorescence is absorbed by hemoglobin, the initial increase and subsequent decrease in fluorescence seem to have been induced by increases in NADH content and CBF, respectively. These findings indicate that the mitochondrial redox state transiently inclines to the reduction side synchronous to the onset of DC-deflection and that it normalizes within 120 s after deflection.

Animals↗
PubMed2000

Kinetic analysis of the reaction catalyzed by chitinase A1 from Bacillus circulans WL-12 toward the novel substrates, partially N-deacetylated 4-methylumbelliferyl chitobiosides.

The kinetic behavior of chitinase A1 from Bacillus circulans WL-12 was investigated using the novel fluorogenic substrates, N-deacetylated 4-methylumbelliferyl chitobiosides [GlcN-GlcNAc-UMB (2), GlcNAc-GlcN-UMB (3), and (GlcN)(2)-UMB (4)], and the results were compared with those obtained using 4-methylumbelliferyl N, N'-diacetylchitobiose [(GlcNAc)(2)-UMB (1)] as the substrate. The chitinase did not release the UMB moiety from compound 4, but successfully released UMB from the other substrates. k(cat)/K(m) values determined from the releasing rate of the UMB moiety were: 145.3 for 1, 8.3 for 2, and 0.1 s(-1) M(-1) for 3. The lack of an N-acetyl group at subsite (-1) reduced the activity to a level 0.1% of that obtained with compound 1, while the absence of the N-acetyl group at subsite (-2) reduced the relative activity to 5.7%. These observations strongly support the theory that chitinase A1 catalysis occurs via a 'substrate-assisted' mechanism. Using these novel fluorogenic substrates, we were able to quantitatively evaluate the recognition specificity of subsite (-2) toward the N-acetyl group of the substrate sugar residue. The (-2) subsite of chitinase A1 was found to specifically recognize an N-acetylated sugar residue, but this specificity was not as strict as that found in subsite (-1).

Acetylation↗
PubMed2000

Inhibition of Fas-mediated fulminant hepatitis in CrmA gene-transfected mice.

Hyperimmune response via Fas/Fas-ligand and perforin/granzyme pathways may be essential in pathogenesis of virus-induced fulminant hepatitis. CrmA inhibits activation of caspases and granzyme B, suggesting it may block these pathways. We investigated whether CrmA expression would inhibit Fas-associated lethal hepatitis in mice. We successfully generated AxCALNLCrmA, a recombinant adenovirus expressing CrmA gene with a Cre-mediated switching cassette. We increased CrmA expression level in the liver transfected with AxCALNLCrmA (10(9) pfu) by increasing administration dose (10(7)-10(9) pfu) of AxCANCre, a recombinant, adenovirus-expressing Cre gene. Injection of anti-Fas antibody into the control mice rapidly led to animal death due to massive liver apoptosis, while the apoptosis was dramatically reduced in the CrmA-expressed mice. The animal survival increased with an increase of CrmA expression. The formation of active caspase-3 was markedly inhibited in the crmA-transfected hepatocytes in vitro. These results suggest that crmA is an effective gene that can inhibit immune-related liver apoptosis.

Adenoviridae↗
PubMed2000

Cytokine-inducing macromolecular glycolipids from Enterococcus hirae: improved method for separation and analysis of its effects on cellular activation.

Previously, we showed that several minor macromolecular glycolipids accounting for less than 5% of the lipoteichoic acid (LTA) fraction from Enterococcus hirae ATCC 9790 possess cytokine-inducing activity, whereas the purified LTA does not. In other words, the immunobiological activity of the LTA fraction reported in the 1980s was not attributable to LTA itself, but to other glycolipids coexisting in the fraction. In the present study, we improved the procedure of separation of the active glycolipids and evaluated their effects on cellular activation. The immunobiologically active glycolipids were separated from the crude glycolipid fraction obtained by hot phenol-water extraction of the cells. The total yield of active glycolipids was about fivefold higher than that separated by the previous method. Interleukin-6-inducing activities of the active glycolipids from 1,25-dihydroxy vitamin D(3)-differentiated human monocytic leukemia cells, THP-1, were inhibited by anti-CD14 mAbs in a dose-dependent manner. Macrophages from Toll-like receptor (TLR)-2-deficient or -4-deficient mice completely lacked the ability to produce tumor necrosis factor-alpha on stimulation with active glycolipids. These observations indicated that the cellular activation by the active glycolipids from E. hirae is mediated by CD14 and by both TLR2 and TLR4.

Animals↗
PubMed2000

Adenovirus-mediated transfer of caspase-8 augments cell death in gliomas: implication for gene therapy.

Caspase-8 is a member of the family of caspases, which are involved in the execution of apoptosis. To investigate whether caspase-8 can be used for gene therapy of gliomas, we transduced A-172 and U251 glioma cells with the caspase-8 gene via an adenoviral vector (Adv) controlled by the chicken beta-actin (CA) promoter (Advcaspase-8), and found that a similar level of caspase-8 protein induced A-172 cells to undergo necrotic cell death and U251 cells to undergo apoptotic cell death. Neither Bcl-XL nor Bcl-2, which play important roles in antiapoptotic mechanisms in gliomas, protected glioma cells from apoptosis induced by overexpression of caspase-8. Injection of Adv-caspase-8 suppressed the in vivo growth of U251 xenografts, in which apoptotic cell death remarkably increased as revealed by TUNEL analysis. Finally, we assessed whether gene therapy with a tissue-specific promoter, the myelin basic protein (MBP) promoter, is applicable to gliomas. Adv for caspase-8 controlled by the MBP promoter induced drastic apoptosis in U251 and U-373MG glioma cells, whereas it did not induce apoptosis in human endothelial cells, fibroblasts, and nerve growth factor-treated PC12 cells. These results indicate that Adv for caspase-8 effectively induced cell death in gliomas, and that this approach may be a useful modality for gene therapy of gliomas.

Actins↗
PubMed2000

Solution structure of the chitin-binding domain of Bacillus circulans WL-12 chitinase A1.

The three-dimensional structure of the chitin-binding domain (ChBD) of chitinase A1 (ChiA1) from a Gram-positive bacterium, Bacillus circulans WL-12, was determined by means of multidimensional heteronuclear NMR methods. ChiA1 is a glycosidase that hydrolyzes chitin and is composed of an N-terminal catalytic domain, two fibronectin type III-like domains, and C-terminal ChBD(ChiA1) (45 residues, Ala(655)-Gln(699)), which binds specifically to insoluble chitin. ChBD(ChiA1) has a compact and globular structure with the topology of a twisted beta-sandwich. This domain contains two antiparallel beta-sheets, one composed of three strands and the other of two strands. The core region formed by the hydrophobic and aromatic residues makes the overall structure rigid and compact. The overall topology of ChBD(ChiA1) is similar to that of the cellulose-binding domain (CBD) of Erwinia chrysanthemi endoglucanase Z (CBD(EGZ)). However, ChBD(ChiA1) lacks the three aromatic residues aligned linearly and exposed to the solvent, which probably interact with cellulose in CBDs. Therefore, the binding mechanism of a group of ChBDs including ChBD(ChiA1) may be different from that proposed for CBDs.

Amino Acid Sequence↗
PubMed2000

Chemo- and enzymatic synthesis of partially and fully N-deacetylated 4-methylumbelliferyl chitobiosides: fluorogenic substrates for chitinase.

Partially and fully N-deacetylated 4-methylumberlliferyl chitobioside (1) derivatives, such as GlcN-GlcNAc-UMB (2), GlcNAc-GlcN-UMB (3), and (GlcN)2-UMB (4), were synthesized using chemo- and enzymatic procedure. Fluorescent aglycon was released from the chitobiosides 1, 2 and 3 by the action of chitinase. These UMB glycosides of heterochitobiose were versatile probes for the investigation of substrate binding chitinase from various sources.

Bacillus↗
PubMed2000

Adjuvant effect of antibodies against von Willebrand Factor, fibrinogen, and fibronectin on staphylokinase-induced thrombolysis as measured using mural thrombi formed in rat mesenteric venules.

The change in thrombus mass during thrombolytic therapy is thought to be the difference between its growth and its degradation induced by thrombolytic agents. Platelets play a pivotal role in arterial thrombosis and bind to each other and to exposed subendothelial matrices via adhesive proteins such as von Willebrand Factor, fibrinogen, and fibronectin. The aim of the present study was to assess whether administration of antibodies against these adhesive proteins, in conjunction with plasminogen activator, could enhance the degradation of platelet-rich thrombus. Mural platelet-rich thrombi were formed in rat mesenteric venules using He-Ne laser irradiation. Recombinant staphylokinase was infused continuously and polyclonal antibodies against adhesive proteins were given by bolus injection. The thrombolytic process was analysed using computer-enhanced image analysis software. Administration of each of the antibodies enhanced staphylokinase-induced thrombolysis.

Adjuvants, Immunologic↗
PubMed2000

Red wine polyphenols inhibit proliferation of vascular smooth muscle cells and downregulate expression of cyclin A gene.

BACKGROUND: Red wine polyphenols have been shown to contribute to the "French paradox" phenomenon, which consists of lower morbidity and mortality from coronary heart disease in the French population. Although vascular smooth muscle cell (VSMC) proliferation plays an important role in the progression of atherosclerotic lesions, the effects of red wine polyphenols on VSMC proliferation have not been elucidated. METHODS AND RESULTS: We extracted the total polyphenolic fraction from red wine (RW-PF) by column chromatography. Treatment with RW-PF showed a potent inhibitory effect on the proliferation and DNA synthesis of cultured rat aortic smooth muscle cells (RASMCs). In contrast, the inhibitory effect of RW-PF on the proliferation of bovine carotid endothelial cells was observed only at much higher concentrations. To elucidate the molecular mechanisms of this antiproliferative effect of RW-PF on RASMCs, we investigated the effects of RW-PF on cell cycle regulation. RW-PF downregulated the expression of cyclin A mRNA and cyclin A promoter activity. In addition, RW-PF decreased the binding of nuclear proteins to the activating transcription factor (ATF) site in the cyclin A promoter and downregulated the mRNA levels of transcription factors, cAMP-responsive element-binding protein (CREB), and ATF-1. CONCLUSIONS: These results suggest that the downregulation of cyclin A gene expression may contribute to the antiproliferative effect of red wine polyphenols on RASMCs through the inhibition of transcription factor expression.

Animals↗
PubMed2000

Dopaminergic loss and inclusion body formation in alpha-synuclein mice: implications for neurodegenerative disorders.

To elucidate the role of the synaptic protein alpha-synuclein in neurodegenerative disorders, transgenic mice expressing wild-type human alpha-synuclein were generated. Neuronal expression of human alpha-synuclein resulted in progressive accumulation of alpha-synuclein-and ubiquitin-immunoreactive inclusions in neurons in the neocortex, hippocampus, and substantia nigra. Ultrastructural analysis revealed both electron-dense intranuclear deposits and cytoplasmic inclusions. These alterations were associated with loss of dopaminergic terminals in the basal ganglia and with motor impairments. These results suggest that accumulation of wild-type alpha-synuclein may play a causal role in Parkinson's disease and related conditions.

Animals↗
PubMed2000

The prepro vasoactive intestinal contractor (VIC)/endothelin-2 gene (EDN2): structure, evolution, production, and embryonic expression.

Murine vasoactive intestinal contractor (VIC) and its human analog endothelin-2 (ET2) are potent vasoactive hormones composed of 21 amino acids. To study the structural characteristics of the VIC/ET2 gene (HGMW-approved symbol EDN2), we isolated the full length of the mouse VIC gene. Sequence analysis indicates that a biologically active mature VIC peptide is produced from a 175-residue precursor protein; preproVIC (PPVIC). Several remarkable similarities of the PPVIC gene to the human preproendothelin-1 gene strongly suggest that the two genes have arisen from a common progenitor by gene duplication. Transfection of ACHN adenocarcinoma cells with the cDNA resulted in the production of VIC peptide. VIC production was increased by the deletion of the 3'-untranslated region, which contains an AU-rich mRNA destabilizing sequence. Increased PPVIC gene expression during the late embryonic stage suggests an important function in development. This study provides the basis for disruption and regulation analysis of the gene, which may lead to a better understanding of VIC/ET2's physiological significance.

Amino Acid Sequence↗
PubMed2000

Prostanoids regulate proliferation of vascular smooth muscle cells induced by arginine vasopressin.

The aim of the present study was to investigate the effect of arginine [Arg(8)]vasopressin (vasopressin) on proliferation of vascular smooth muscle cells and the mechanisms underlying the action of vasopressin. To clarify these issues, we used two different types of vascular smooth muscle cells, cultured adult rat aortic smooth muscle cells and A10 cells, a cell line derived from fetal rat aorta. Vasopressin (10(-8) to 10(-6) M) significantly stimulated the proliferation of rat aortic smooth muscle cells in a dose-dependent manner. In contrast, vasopressin significantly inhibited the proliferation of A10 cells. This inhibition was abolished when A10 cells were treated with indomethacin. Vasopressin stimulated the production of prostanoids several-fold in A10 cells but not in rat aortic smooth muscle cells. These effects were completely blocked by the vasopressin V(1) receptor antagonist, 1-¿1-[4-(3-acetylamino-propoxy)benzoyl]4-piperidyl¿-3, 4-dihydro-2(1H)-quinolinone (OPC21268), but not by the vasopressin V(2) receptor antagonist, (+/-)-5-dimethylamino-1-[4-(2-methylbenzoylamino)benzol]-2, 3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC31260). These results indicate that vasopressin has diverse effect on proliferation of vascular smooth muscle cells through the vasopressin V(1) receptor, depending on the production of growth regulatory prostanoids.

6-Ketoprostaglandin F1 alpha↗
PubMed2000

Microchip capillary electrophoresis using on-line chemiluminescence detection.

Chemiluminescence detection was used in capillary electrophoresis integrated on a microchip. Quartz microchips have two main channels and four reservoirs. Dansyl-lysine and -glycine were separated and detected with bis[(2-(3,6,9-trioxadecanyloxycarbony)-4-nitrophenyl]oxalate as peroxyoxalate chemiluminescent reagent. These dansyl amino acids came into contact with the chemiluminescence reagent to produce visible light at the interface between the separation channel and chemiluminescence reagent-containing reservoir. The detection limit (S/N = 3) for dansyl-lysine was 1 x 10(-5) M, which corresponded to the very small mass detection limit of ca. 0.4 fmol. However, the concentration sensitivity in the present system was approximately two orders of magnitude lower than that in the conventional capillary electrophoresis-chemiluminescence detection system. The relative standard deviations of migration time and peak height for dansyl-lysine were 4.2 and 4.5%, respectively. A channel conditioning before every run and an appropriate control of voltages were needed for the reproducible results. The present system had advantages in rapid separation time (within 40 s), small (several 10 pI) and accurate sample injection method using a cross-shaped injector, and simplification and miniaturization of the detection device.

Amino Acids↗
PubMed2000

Visuoperceptual impairment in dementia with Lewy bodies.

BACKGROUND: In dementia with Lewy bodies (DLB), vision-related cognitive and behavioral symptoms are common, and involvement of the occipital visual cortices has been demonstrated in functional neuroimaging studies. OBJECTIVES: To delineate visuoperceptual disturbance in patients with DLB in comparison with that in patients with Alzheimer disease and to explore the relationship between visuoperceptual disturbance and the vision-related cognitive and behavioral symptoms. DESIGN: Case-control study. SETTING: Research-oriented hospital. PATIENTS: Twenty-four patients with probable DLB (based on criteria of the Consortium on DLB International Workshop) and 48 patients with probable Alzheimer disease (based on criteria of the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association) who were matched to those with DLB 2:1 by age, sex, education, and Mini-Mental State Examination score. MAIN OUTCOME MEASURES: Four test items to examine visuoperceptual functions, including the object size discrimination, form discrimination, overlapping figure identification, and visual counting tasks. RESULTS: Compared with patients with probable Alzheimer disease, patients with probable DLB scored significantly lower on all the visuoperceptive tasks (P<.04 to P<.001). In the DLB group, patients with visual hallucinations (n = 18) scored significantly lower on the overlapping figure identification (P = .01) than those without them (n = 6), and patients with television misidentifications (n = 5) scored significantly lower on the size discrimination (P<.001), form discrimination (P = .01), and visual counting (P = .007) than those without them (n = 19). CONCLUSIONS: Visual perception is defective in probable DLB. The defective visual perception plays a role in development of visual hallucinations, delusional misidentifications, visual agnosias, and visuoconstructive disability charcteristic of DLB.

Aged↗