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H Ito

Publications and source records attributed to H Ito.

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

Molecular cloning and biological activity of a novel Ha-Ras suppressor gene predominantly expressed in skeletal muscle, heart, brain, and bone marrow by differential display using clonal mouse EC cells, ATDC5.

We cloned a cDNA encoding a novel mouse protein, named A-C1, by differential display between two mouse cell lines: embryonic fibroblast C3H10T1/2 and chondrogenic ATDC5. The deduced amino acid sequence of A-C1 consists of 167 amino acids and shows 46% identity with that of a ras-responsive gene, rat Ha-rev107. Northern blot analysis showed a distinct hybridization band of 3.2 kilobases. Expression of A-C1 mRNA was detected in undifferentiated ATDC5 cells and myoblastic C2C12 cells, while none of C3H10T1/2 cells, NIH3T3 fibroblasts, Balb/c 3T3 fibroblasts, osteoblastic MC3T3-E1 cells, and ST2 bone marrow stromal cells expressed A-C1 mRNA in vitro. Moreover, A-C1 mRNA was expressed in skeletal muscle, heart, brain, and bone marrow in adult mice. By in situ hybridization, A-C1 gene expression was localized in hippocampus as well as bone marrow cells. By immunocytochemistry, A-C1 protein was detected in the cytoplasm as well as perinuclear region of the cells. Transfection of A-C1 cDNA into Ha-ras-transformed NIH3T3 cell line caused increase in the number of flat colonies and inhibition of cell growth. Our data indicate that A-C1 is expressed in some specific tissues in vivo and modulates Ha-ras-mediated signaling pathway.

3T3 Cells↗
PubMed1999

Molecular cloning of brain-specific GD1alpha synthase (ST6GalNAc V) containing CAG/Glutamine repeats.

A novel member of the mouse CMP-NeuAc: beta-N-acetylgalactosaminide alpha2,6-sialyltransferase (ST6GalNAc) subfamily, designated ST6GalNAc V, was identified by BLAST analysis of expressed sequence tags. The sequence of the longest cDNA clone of ST6GalNAc V encoded a type II membrane protein with 8 amino acids comprising the cytoplasmic domain, 21 amino acids comprising the transmembrane region, and 306 amino acids comprising the catalytic domain. The predicted amino acid sequence showed homology to the previously cloned ST6GalNAc III and IV, with common amino acid sequences in sialyl motifs L and S among these three enzymes. Eleven CAG repeats were found in the stem region. A fusion protein with protein A and extracts from L cells transfected with ST6GalNAc V in a expression vector showed enzyme activity of alpha2,6-sialyltransferase almost exclusively for GM1b, but not toward glycoproteins. Sialidase treatment and thin layer chromatography immunostaining revealed that the product was GD1alpha. Northern blotting revealed that three transcripts of the gene were expressed specifically in brain tissues. It is concluded that this enzyme is involved in the synthesis of GD1alpha in the nervous tissues, and the CAG repeats may have implications in neurodegenerative diseases.

Amino Acid Sequence↗
PubMed1999

Facilitation of renal kallikrein-kinin system prevents the development of hypertension by inhibition of sodium retention.

We have previously reported that the renal kallikrein-kinin system suppressed the development of hypertension, using kininogen deficient Brown Norway Katholiek rats. Kinins were degraded in urine mainly by carboxypeptidase Y-like kininase (CPY). Blockade of renal kinin degradation may prevent the experimental hypertension through the facilitation of the renal kallikrein-kinin system. Daily administration of ebelactone B (EB), which is isolated from Actinomycetes and strongly inhibits CPY, from the first day of deoxycorticosterone acetate (DOCA)-salt treatment for 4 weeks completely blocked hypertension in Sprague-Dawley rats. This treatment reduced sodium levels in erythrocytes and cerebrospinal fluids (CSF) significantly. By contrast, an ACE inhibitor, lisinopril did not prevent hypertension. The development of hypertension in young spontaneously hypertensive rats was also blunted by EB with reductions in sodium levels in erythrocytes and in CSF. The arterial kinin levels in rats undergoing DOCA-salt treatment were 2.2 +/- 0.2 pg/ml, which were increased significantly to 4.6 +/- 0.4 pg/ml with captopril (10 mg/kg, s.c.). The increased kinin levels were less than those to show hypotension. EB did not increase the arterial kinin levels, with significant increase in urinary kinin secretion. These results suggested that facilitation of the renal kallikrein-kinin system by inhibition of kinin degradation on the luminal side of the renal tubules may effectively prevent hypertension.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Radiation sensitivity of Bacillus cereus with and without a crystalline surface protein layer.

The radiation sensitivity of four strains of Bacillus cereus was investigated with attention to bacterial surface structure. All four strains were sensitive to radiation with gamma rays (D(10)=0.4 kGy). No crystalline surface protein layer could be detected on the cell surface. When cultured on solid media, an S-layer covered the cells of the two strains, and they were 2.6 times as resistant to radiation as the two reference strains without an S-layer. In SDS-PAGE, a major 97-kDa band from the resistant strains from plate cultures was replaced by a ca. 85-kDa protein band in samples from broth cultures. Electron microscopy, SDS-PAGE, Western blot and fluorescent antibody staining indicated that the higher resistance to radiation of the clinical strains from plate cultures was associated with the presence of the S-layer on the cell surface.

Bacillus cereus↗
PubMed1999

Identification of an amino acid transporter associated with the cystinuria-related type II membrane glycoprotein.

We identified an amino acid transporter that is associated with the cystinuria-related type II membrane glycoprotein, rBAT (related to b(0,+) amino acid transporter). The transporter designated BAT1 (b(0, +)-type amino acid transporter 1) from rat kidney was found to be structurally related to recently identified amino acid transporters for system L, system y(+)L, and system x(-)C, which are linked, via a disulfide bond, to the other type II membrane glycoprotein, 4F2hc (4F2 heavy chain). In the nonreducing condition, a 125-kDa band, which seems to correspond to the heterodimeric complex of BAT1 and rBAT, was detected in rat kidney with anti-BAT1 antibody. The band was shifted to 41 kDa in the reducing condition, confirming that BAT1 and rBAT are linked via a disulfide bond. The BAT1 and rBAT proteins were shown to be colocalized in the apical membrane of the renal proximal tubules where massive cystine transport had been proposed. When expressed in COS-7 cells with rBAT, but not with 4F2hc, BAT1 exhibited a Na(+)-independent transport of cystine as well as basic and neutral amino acids with the properties of system b(0,+). The results from the present investigation were used to establish a family of amino acid transporters associated with type II membrane glycoproteins.

ATP-Binding Cassette Transporters↗
PubMed1999

Evaluation of the therapeutic effect of radiotherapy on cervical cancer using magnetic resonance imaging.

PURPOSE: This study was performed to evaluate magnetic resonance imaging (MRI) in determining the therapeutic effect of radiotherapy (RT) on cervical cancer. METHODS AND MATERIALS: Serial MRI studies were performed in 42 patients with predominantly advanced cervical cancer before, during, and after radiotherapy. Patients underwent external irradiation combined with high-dose-rate intracavitary (HDR) brachytherapy. T-2 weighted spin-echo pulse sequences with long repetition and echo times were used at a field strength of 1.5 T. Multiple punch biopsies of the cervix were obtained from the high-signal intensity area in all patients at the same time as the MRI. RESULT: In biopsies performed immediately after RT, no residual tumors were found in 36 patients (86%); in 6 patients, residual tumors were observed. The simultaneous MRI study demonstrated no high-signal intensity on T2-weighted images in 28 patients. A high-signal area was observed in 14 patients, and this disappeared 3 months after RT in 8 patients with a negative histological study. The sensitivity, specificity, and accuracy of MRI studies at 3 months after RT were 100%. When the relationship between reduction of tumor volume at 30 Gy and local tumor control was analyzed, every patient with a reduction under 30% gained local control. Also, patients with no residual tumors 3 months after RT gained local control. CONCLUSION: MRI studies performed at 30 Gy of external irradiation and 3 months after RT were predictive factors of local control.

Adenocarcinoma↗
PubMed1999

Thymidine phosphorylase expression is associated with both increase of intratumoral microvessels and decrease of apoptosis in human colorectal carcinomas.

Thymidine phosphorylase (dThdPase)/platelet-derived endothelial cell growth factor is expressed at higher levels in a variety of human carcinomas than it is in adjacent normal tissue. The higher expression is associated with an increase of intratumoral microvessel density (IMVD) and an unfavorable patient prognosis. We examined the role of dThdPase in apoptosis, cell proliferation, IMVD, and p53 expression in human colorectal carcinomas. dThdPase expression was noted in 13 of 36 (36.1%) Dukes' A and B carcinomas and in 13 of 28 (46.3%) Dukes' C and D carcinomas. At least 10 areas consisting of carcinoma cells with diffuse dThdPase expression from the 26 dThdPase-positive tumors (category I) and 10 areas without dThdPase expression from the 38 negative tumors (category II) were selected from each case. For stage A and B tumors, the mean IMVDs were 64.8 +/- 33.7 in category I and 33.2 +/- 12.6 in category II tumors, whereas for stage C and D tumors, the mean IMVDs were 77.6 +/- 27.2 in the category I and 34.7 +/- 14.0 in the category II tumors. The mean IMVD was significantly higher in category I than in category II tumors (P < 0.01). The mean apoptotic indices (AIs; percentage of apoptotic cells) were 2.7 +/- 1.7 in the category I and 5.4 +/- 2.2 in the category II carcinomas of stages A and B and 1.4 +/- 0.5 in category I and 5.3 +/- 2.3 in category II carcinomas of stages C and D, and the value of the mean AI was significantly lower in category I than in category II (P < 0.01), regardless of the Dukes' stage. AI and IMVD showed a significant inverse correlation (P < 0.001). There was no significant difference in the frequency of p53 expression between the two categories. These results indicated that dThdPase expression provides an advantage for tumor growth of human colonic carcinomas not only by increasing the intratumoral microvessels but also by attenuation of apoptosis, which might occur via a p53 gene-independent pathway.

Apoptosis↗
PubMed1999

Auditory brainstem responses in patients with autonomic failure with Parkinson's disease and multiple system atrophy.

Auditory brainstem responses (ABRs) were examined in six patients with autonomic failure with Parkinson's disease (AF with PD) and 10 patients with autonomic failure with multiple system atrophy (AF with MSA), all of which showed marked parkinsonian features as a principal sign. We designated the central abnormalities of ABRs as prolongation of latencies (wave III or V) and interpeak latencies (IPLs; I-III, I-V, and III-V IPL) or decreased amplitude ratios of wave III or V to those of wave I (less than 1.0). None of the patients with AF with PD showed abnormalities in ABRs. In contrast, in those with AF with MSA, the peak latencies or IPLs were prolonged in two of the 10 patients, and the amplitude ratios of wave III or V to those of wave I were decreased in other two of these patients. Moreover, both prolongation of latencies and a decreased ratio were observed in other one. Overall, five of the 10 patients with AF with MSA showed central abnormalities in ABRs. It is clinically difficult to differentiate AF with PD from AF with MSA, particularly when no cerebellar signs are apparent in AF with MSA patients. When central abnormalities of ABRs are observed in AF patients, AF with MSA should be suspected rather than AF with PD. In conclusion, ABRs provide useful information for the differential diagnosis of AF with PD and AF with MSA.

Aged↗
PubMed1999

Bone morphogenetic protein-6 and parathyroid hormone-related protein coordinately regulate the hypertrophic conversion in mouse clonal chondrogenic EC cells, ATDC5.

We evaluated the roles of bone morphogenetic protein (BMP)-6, BMP-4 and parathyroid hormone-related protein (PTHrP) in the hypertrophic conversion using mouse chondrogenic EC cells, ATDC5. In ATDC5 cells, the expression of BMP-6 and PTHrP receptor mRNAs increased in parallel with the progression of chondrogenic differentiation of these cells, exhibiting a time course similar to that of type II collagen, a phenotypic marker of proliferating chondrocytes, while BMP-4 mRNA was continuously expressed throughout the differentiation processes. The expression of type X collagen mRNA, a phenotypic marker of hypertrophic chondrocytes, was upregulated by BMP-6 and BMP-4, and downregulated by PTHrP(1-141). The expression of BMP-6 mRNA was upregulated while that of BMP-4 mRNA was downregulated by both BMP-6 and BMP-4. Moreover, the expression of BMP-6 mRNA was downregulated by PTHrP(1-141). Furthermore, even in the presence of PTHrP(1-141), BMP-6 increased the transcript level of type X collagen in a dose-dependent manner. These results indicate that transiently expressed BMP-6 promotes the hypertrophic conversion in association with the augmentation of BMP-6 gene expression by BMP signals and that both BMP-6 and PTHrP coordinately regulate the rate of the hypertrophic conversion of ATDC5 cells.

Animals↗
PubMed1999

Hedgehog signaling molecules in bone marrow cells at the initial stage of fracture repair.

Ihh is a secreted protein expressed in chondrocytes in cartilaginous soft callus and thought to be involved in regulation of chondrogenic differentiation in fracture repair processes. However, gene expression and function of Ihh and its signaling molecules, Ptc and Smo, at the initial stage of fracture repair remain unknown. In the present study, we showed by RT-PCR of mouse rib fractures that the upregulation of Ihh mRNA occurred within hours after fracture, immediately followed by that of Ptc mRNA, and that both Ihh and Ptc mRNAs exhibited the time course similar to those of OP and OC mRNAs at the initial stage of fracture repair. The transcript level of Smo mRNA gradually increased within hours after fracture and was continuously maintained throughout the subsequent fracture repair processes. By in situ hybridization analysis, the transcripts of Ptc and Smo genes localized in bone marrow of unfractured ribs, and those of Ihh, Ptc, and Smo were expressed in the vicinity of the fracture site at 8 h after fracture. Furthermore, in adherent bone marrow cells in culture, mrIhh-N upregulated the gene expression of TGF-beta(1) as well as OPGL, a potent stimulator of osteoclastogenesis and osteoclast activity. These observations suggest that Ihh may play roles in the initial stage of fracture repair via TGF-beta(1) and OPGL.

Animals↗
PubMed1999

Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissima.

Chemical investigation on polyphenol-rich fractions of Cowania mexicana and Coleogyne ramosissima (Rosaceae) which showed significant inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), has led to the characterization of 10 compounds including C-glucosidic ellagitannin monomers and dimers from the former plant, and 17 polyphenols including flavonoid glycosides from the latter. The effects of individual components and their analogues with related structures on the TPA-induced EBV-EA activation were then evaluated. Among the compounds isolated from C. mexicana, two C-glucosidic ellagitannins, alienanin B and stenophyllanin A and a nitrile glucoside (lithospermoside), and among the constituents from C. ramosissima, two flavonoid glycosides, isorhamnetin 3-0-beta-D-glucoside and narcissin were revealed to possess strong inhibitory effects on EVB-EA activation, the potencies of which were either comparable to or stronger than that of a green tea polyphenol, (-)-epigallocatechin gallate. These polyphenols except for nitrile glucoside, which was not tested owing to an insufficient amount, were also found to exhibit anti-tumor promoting activity in two-stage mouse skin carcinogenesis using 7,12-dimethylbenz[a]anthracene (DMBA) and TPA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1999

A role for reactive oxygen species in endothelial cell anoikis.

When adherent cells, such as epithelial or endothelial cells, are detached and continuously maintained in suspension, they undergo a form of programmed cell death termed anoikis. We demonstrate that coincident with endothelial cell detachment, there is a dramatic rise in the intracellular level of reactive oxygen species (ROS). Reattachment to a solid surface rapidly attenuates the level of ROS. The mitochondria appear to be the major source of the detachment-induced rise in ROS. The change in the intracellular redox state appears to contribute to endothelial anoikis, because treatment with either the cell-permeant antioxidant N-acetylcysteine or the flavin protein inhibitor diphenylene iodonium is demonstrated to reduce oxidant levels and protect against subsequent cell death. Similarly, the endogenous intracellular level of ROS is shown to correlate with the extent of cell death. Finally, we demonstrate that the activities of both caspases and of the c-Jun N-terminal kinases are modulated by the rise in intracellular ROS levels. These results suggest that oxidants serve as signaling molecules and regulators of anoikis.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1999

Early temporal changes in coronary flow velocity patterns in patients with acute myocardial infarction demonstrating the "no-reflow" phenomenon.

Coronary flow velocity pattern in patients with acute myocardial infarction demonstrating no-reflow phenomenon is characterized with early systolic retrograde flow and rapid deceleration of diastolic flow velocity. In this study, we investigated the early temporal changes in microvascular function in patients with the no-reflow phenomenon. Among 144 patients with a first acute myocardial infarction, 33 exhibited sizable no-reflow phenomenon after coronary reperfusion with myocardial contrast echocardiography. We assessed temporal changes in coronary flow velocity patterns with the Doppler guidewire. The early systolic retrograde flow was observed < or = 10 seconds after reperfusion in 16 patients (group A) or later in 17 patients (331 +/- 327 seconds, group B). Diastolic deceleration rate was higher in group A than in group B at 1 minute after reperfusion. It gradually increased in group B and showed comparable value to group A 10 minutes later. Group A had longer elapsed time from symptom onset to reperfusion and a greater number of infarct Q waves before reperfusion than group B (14 +/- 13 vs 5 +/- 2 hours, p <0.01; and 3 +/- 2 vs 2 +/- 1, p <0.02). In contrast, the incidence of transient ST reelevation shortly after reperfusion was higher in group B (76% vs 25%, p <0.01). Thus, the characteristic coronary flow velocity pattern is either established at the moment of coronary reperfusion or progresses thereafter in patients with no-reflow phenomenon. This suggests different mechanisms of developing ischemic microvascular injury.

Adult↗
PubMed1999

FR145715, a novel histamine H2 receptor antagonist, with specific anti-Helicobacter pylori activities.

The pharmacological profile of N-[3-[2-[N'-(2-methoxyethyl)guanidino]thiazol-4yl]benzyl-ace tamide (FR145715), a novel histamine H2 receptor antagonist, was examined in both in vitro and in vivo models using experimental animals in comparison with ranitidine. In isolated guinea-pig atria, FR145715 antagonized the effect of histamine on heart rate with approximately three times more potent activity than ranitidine. In in vivo experiments, intraduodenal FR145715 dose-dependently inhibited spontaneous gastric acid secretion in rats (Shay's rats), with a ED50 value of 18.4 mg/kg, which was comparable to that of ranitidine (30.5 mg/kg). FR145715 also inhibited histamine-stimulated acid secretion in stomach-perfused anaesthetized rats (Schild's rats), when given intravenously and intraduodenally with ED50 values of 0.59 and 2.72 mg/kg, respectively. Ranitidine displayed more potent activity having respective ED50 values of 0.10 and 0.17 mg/kg. In Heidenhain pouch dogs, intravenous and oral FR145715 dose-dependently inhibited gastrin-stimulated acid secretion with respective ED50 values of 0.12 and 0.32 mg/kg, which were similar to those of ranitidine (0.09 and 0.33 mg/kg). In gastric ulcer models, FR145715 dose-dependently inhibited water immersion restraint stress- and acidified aspirin-induced gastric lesions with ED50 values of 3.2 and 15.1 mg/kg (p.o.), respectively. The comparative compound, ranitidine, also showed beneficial effects on stress-induced gastric ulcers with an ED50 value of 1.5 mg/kg (p.o.). However, it failed to inhibit acidified aspirin-induced gastric ulcers. FR145715 inhibited HCl-induced gastric lesions in rats, while pre-treatment with indomethacin abolished its beneficial effects, suggesting that FR145715 has a so-called cytoprotective effect which is dependent on endogenous prostaglandin production. In addition to its atypical profile as a histamine H2 receptor antagonist, FR145715 exhibited strong anti-microbial activities against strains of Helicobacter pylori (H. pylori) with a mean minimal inhibitory concentration value of 0.32 microg/ml. Moreover, FR145715 showed no anti-microbial effects on 25 other bacteria examined. In addition, in vivo experiments using gnotobiotic piglets infected with H. pylori, FR145715 (16 mg/kg, t.i.d.) completely eliminated the organism with reduced intensity of inflammation, when treated orally for 10 days. These data demonstrate that FR145715 is a novel histamine H2 receptor antagonist having potent and selective anti-H. pylori activities as well as cytoprotective properties. The present data suggest that FR145715 might be useful for the patients suffering from ulcer relapse, since the drug might be able to eradicate H. pylori in the stomach, which is considered a key factor to cause ulcer recurrence in humans.

Animals↗
PubMed1999

Generation of influenza A viruses entirely from cloned cDNAs.

We describe a new reverse-genetics system that allows one to efficiently generate influenza A viruses entirely from cloned cDNAs. Human embryonic kidney cells (293T) were transfected with eight plasmids, each encoding a viral RNA of the A/WSN/33 (H1N1) or A/PR/8/34 (H1N1) virus, flanked by the human RNA polymerase I promoter and the mouse RNA polymerase I terminator-together with plasmids encoding viral nucleoprotein and the PB2, PB1, and PA viral polymerases. This strategy yielded >1 x 10(3) plaque-forming units (pfu) of virus per ml of supernatant at 48 hr posttransfection. The addition of plasmids expressing all of the remaining viral structural proteins led to a substantial increase in virus production, 3 x 10(4)-5 x 10(7) pfu/ml. We also used reverse genetics to generate a reassortant virus containing the PB1 gene of the A/PR/8/34 virus, with all other genes representing A/WSN/33. Additional viruses produced by this method had mutations in the PA gene or possessed a foreign epitope in the head of the neuraminidase protein. This efficient system, which does not require helper virus infection, should be useful in viral mutagenesis studies and in the production of vaccines and gene therapy vectors.

Animals↗
PubMed1999

Sphingosine 1-phosphate regulates heat shock protein 27 induction by a p38 MAP kinase-dependent mechanism in aortic smooth muscle cells.

In an aortic smooth muscle cell line, A10 cells, we investigated the effect of sphingosine 1-phosphate on the induction of heat shock protein 27 (HSP27), a low-molecular-weight heat shock protein. Sphingosine 1-phosphate significantly induced the accumulation of HSP27 in a pertussis toxin-sensitive manner. The effect was dose-dependent in the range between 0.1 and 30 microM. Sphingosine 1-phosphate stimulated an increase in the levels of mRNA for HSP27. Sphingosine 1-phosphate stimulated both p42/p44 mitogen-activated protein (MAP) kinase and p38 MAP kinase activation. PD98059, an inhibitor of the upstream kinase that activates p42/p44 MAP kinase, did not affect sphingosine 1-phosphate-stimulated HSP27 induction. In contrast, SB203580, an inhibitor of p38 MAP kinase, reduced sphingosine 1-phosphate-induced HSP27 induction. SB203580 reduced the levels of mRNA for HSP27 induced by sphingosine 1-phosphate. These results indicate that sphingosine 1-phosphate stimulates the induction of HSP27 via p38 MAP kinase activation in aortic smooth muscle cells.

Animals↗
PubMed1999

TAK-778, a novel synthetic 3-benzothiepin derivative, promotes chondrogenesis in vitro and in vivo.

TAK-778, a novel synthetic 3-benzothiepin derivative, stimulates the formation of cartilaginous nodules in mouse chondroprogenitor-like ATDC5 cells in vitro in association with upregulation of the gene expression of transforming growth factor-beta(2), but not bone morphogenetic protein-4 and insulin-like growth factor-I. One-shot injection of the TAK-778-containing sustained-release microcapsules accelerated the repair process of the full thickness defects of articular cartilage in rabbit knees. Our in vitro and in vivo results indicate that TAK-778 may be a therapeutically useful synthetic agent for articular cartilage repair.

Animals↗