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Y Shibata

Publications and source records attributed to Y Shibata.

At least 163 records · Page 9Linked to original sources
PubMed1999

Interactions between cytoskeletal components during myoplasm rearrangement in ascidian eggs.

Ooplasmic segregation in ascidian eggs consists of two phases of cytoplasmic movement, the first phase is mediated by the microfilament system and the second is mediated by the microtubule system. Recently, two novel proteins, p58 and myoplasmin-C1, which are localized to the myoplasm, were suggested to have important roles in muscle differentiation. In order to analyze the molecular mechanisms underlying ooplasmic segregation, the interactions between actin, tubulin, p58 and myoplasmin-C1 were examined. During the first segregation, microtubule meshwork in the unfertilized egg disappeared. At the second segregation, a novel structure of the microtubules that extended from the sperm aster and localized in the cortical region of the myoplasm was found. Moreover, uniform distribution of the cortical actin filament was observed at the second segregation. During the course of myoplasm rearrangement, p58 and myoplasmin-C1 are colocalized and can form a molecular complex in vitro. This complex of p58 and myoplasmin-C1 is a good candidate for a cytoskeletal component of the myoplasm, and is likely to be involved in the correct distribution of cytoplasmic determinants.

Actins↗
PubMed1999

Novel DNA-binding ligands with sequence selectivity based on hydrophobic structure.

We have developed diamino-bistetrahydrofuran compounds (diamino-bisTHF) as new DNA binding molecules. Diamino-bisTHF (3:RR8) stabilized GC-rich duplex DNA with sequence specificity. DNA binding affinity increased as the alkyl chain was lengthened, indicating that the hydrophobic interaction is essential for DNA binding. It was also found that DNA binding affinity of the ligands depends on the stereochemistry of the amino group. In thermodynamic evaluation, diamino-bisTHF (3:RR8) showed a high affinity to the 12 bp duplex at a molar ratio of 1:1.

Base Sequence↗
PubMed1999

Gamma-radiation induces leaf trichome formation in Arabidopsis.

We observed induction of additional trichome formation on the adaxial surface of mature leaves of Arabidopsis after massive doses (1-3 kilograys) of gamma-radiation from cobalt-60. A typical increase in trichome number was observed in the seventh leaf when the full expansion of the fifth leaf was irradiated. Under normal growth conditions, trichome numbers on the adaxial surface of seventh leaf of the Arabidopsis ecotypes Columbia (Col) and Landsberg erecta (Ler) were 122.5 +/- 22.7 and 57.5 +/- 14.5, respectively. However, gamma-radiation induced additional trichome formation and the numbers rose to 207.9 +/- 43.7 and 95.0 +/- 27.1 in Col and Ler, respectively. In Col the shape of new trichomes was intact and their formation was spatially maintained at equal distances from other trichomes. In Ler trichome morphology was aberrant and the formation was relatively random. Treatment with antioxidants before gamma-irradiation suppressed the increase in trichome number, and treatment with methyl viologen and light induced small trichomes. These results suggest that gamma-radiation-induced trichome formation is mediated by active oxygen species generated by water radiolysis. gamma-Radiation-induced trichome formation was blocked in the trichome mutants ttg-1, gl1-1, and gl2-1. These results suggest that gamma-radiation-induced trichome formation is mediated by the normal trichome developmental pathway.

Arabidopsis↗
PubMed1999

Apoptosis-induced and -suppressed cells in salivary gland adenoid cystic carcinoma: correlation with histological growth patterns.

OBJECTIVE: It is well known that adenoid cystic carcinoma (ACC) arising from salivary glands shows a correlation between prognosis and histological growth patterns. The aim of the study was to evaluate whether three growth patterns of ACC are related to the distributions of apoptosis-induced and -suppressed tumor cells. MATERIALS AND METHODS: We examined 77 cases of ACC including tubular (18 cases), glandular (50) and solid (9) patterns. In order to visualize the apoptotic cells, terminal deoxynucleotidyl transferase (TdT)- mediated dUTP-biotin nick end labeling (TUNEL) and avidin-biotin complex staining using Lewis Y (LeY) antibody were applied to paraffin sections. For detection of the apoptosis-suppressed cells, immunohistochemistry employing bcl-2 antibody was utilized. RESULTS: Apoptosis index (AI) based on the TUNEL-stained specimens were tubular, 7.0; glandular 2.4; solid, 5.1. In tubular type, apoptotic cells were frequently located in the inner tubular layer rather than the outer layer. Solid type had scattered apoptotic cells in the nests. Bcl-2 expression was found in 61% of tubular, 20% of glandular and 22% of solid cases. The localization of bcl-2 protein was noticed in outer tubular cells, and peripheral cells or undifferentiated cells in solid pattern. CONCLUSIONS: The peculiar distribution of apoptotic cells may result from the various proportions and distinctive arrangement of neoplastic ductal cells and neoplastic myoepithelial cells in ACC. Apoptotic cells and bcl-2 positive apoptosis-suppressed cells may participate in the construction of characteristic histological appearances of ACC.

Apoptosis↗
PubMed1999

A novel gene required for rhamnose-glucose polysaccharide synthesis in Streptococcus mutans.

Gene rgpG is required for biosynthesis of rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans. Its deduced amino acid sequence had similarity to WecA, which initiates syntheses of enterobacterial common antigen and some O antigens in Escherichia coli. Gene rgpG complemented a wecA mutation of E. coli, suggesting that rgpG may function similarly in RGP synthesis.

Cloning, Molecular↗
PubMed1999

Connexin43 expression in network-forming cells at the submucosal-muscular border of guinea pig and dog colon.

The tissue-specific expression of connexin subtypes in gap junctions between the interstitial cells and smooth muscle cells in the submuscular plexus of the colon has a functional importance in relation to intestinal pacemaker activity. Immunocytochemical observations of two types of connexin molecules, connexin43 and connexin45, were made with a confocal laser scanning microscope on cryosections of freshly frozen dog, guinea pig, mouse and rat proximal colon. Connexin43 immunoreactivity appeared as a series of dots along the submuscular plexus of guinea pig and dog. In contrast, connexin43 immunoreactivity was not found in mouse and rat colon. Connexin43 immunoreactivity was not observed in the colon muscular layer in the four animal species examined. In double-stained materials with a marker for either vimentin or smooth muscle actin, connexin43 immunoreactivity was colocalized with vimentin immunoreactivity, whereas it was not with either smooth muscle actin immunoreactivity or phalloidin reactivity. This indicated that the connexin43-expressing cells possess a vimentin-positive fibroblast-like nature rather than a smooth muscle-like one. In addition, in guinea pig colon, connexin43 immunoreactivity colocalized with c-Kit immunoreactivity. In conclusion, network-forming cells are connected by connexin43 gap junctions in the submuscular plexus of guinea pig and dog colon, most likely indicating that interstitial cells act as an intestinal pacemaker and conductive system.

Actins↗
PubMed1999

Determination of granulocyte-specific antigens on neutrophil FcA receptor IIIb by PCR-preferential homoduplex formation assay, and gene frequencies in the Japanese population.

BACKGROUND AND OBJECTIVES: Granulocyte-specific antigens play an important role in provoking immune neutropenia and transfusion reactions. We developed a new DNA-typing method, PCR-preferential homoduplex formation assay (PHFA), to determine granulocyte-specific antigens on the neutrophil Fcgamma receptor IIIb (FcgammaRIIIb, CD16b), namely, the NA1, NA2, and SH antigens and their gene frequencies in the Japanese population. MATERIALS AND METHODS: Four hundred unrelated healthy Japanese blood donors were typed using PCR-PHFA. To confirm the accuracy of the results of FcgammaRIIIB genotyping using PCR-PHFA, PCR-sequence-specific primer (SSP) typing and PCR-restriction fragment length polymorphism (RFLP) typing were carried out in another 20 samples for comparison. RESULTS: The results of PCR-PHFA typing agreed well with other methods. The frequencies of the FcgammaRIIIB alleles were 62.2, 37.8, 0 and 0% for NA1, NA2, SH, and 'NA-null', respectively. CONCLUSION: The PCR-PHFA method can be semi-automated easily with computer-based assignment and is suitable for typing both small and large numbers of samples. In the Japanese population, the frequency of NA1 is about double that in Caucasians (32.5%), and the SH allele is rare.

Alleles↗
PubMed1999

Cycloprodigiosin hydrochloride obtained from Pseudoalteromonas denitrificans is a potent antimalarial agent.

Cycloprodigiosin hydrochloride (cPrG*HCl) is a stable fluorescent red pigment obtained from the marine bacterium Pseudoalteromonas denitrificans. It was found that the compound was incorporated into Plasmodium falciparum cells upon incubation and exhibited a potent antimalarial activity with the concentration required for 50% of the activity being 11 nM, which is stronger than that of chloroquine, a well-known antimalarial agent. The compound did not affect growth rate of mammalian cells. Antimalarial activity of cPrG*HCl was also observed in vivo. These results indicate that cPrG*HCl is a potent antimalarial drug.

Animals↗
PubMed1999

First isolation of Sarcocystis hominis from cattle in Japan.

Sarcocystis hominis was first isolated from slaughtered cattle raised in Japan. Cysts were 1,220-4,460 x 80-384 microns in size and their wall was 3 to 6 microns thick and appeared radially striated in the histopathological sections because of the presence of palisade-like villar protrusions on the surface. The protrusions were 3.1-4.3 x 0.7-1.1 microns in size and had many microtubules in the core. Two cynomolgus monkeys, Macaca fascicularis, fed with the Sarcocystis cysts began to pass sporocysts, which measured a size of 14.3-15 x 9.5-10 microns, in the feces 10 days after ingestion.

Animals↗
PubMed1999

Distribution of gap junction protein connexin 37 in smooth muscle cells of the rat trachea and pulmonary artery.

Connexin 37, one of the gap junction protein families, has been detected by Northern blotting in various organs and tissues, and found to be especially abundant in the lung. However, detailed information on the precise types of cells which express connexin 37 has not been previously published. We therefore prepared site-specific connexin 37 antibodies and examined the distribution of connexin 37 immunohistochemically. Connexin 37 was detected in endothelial cells, in the tunica media of both the pulmonary artery and the aorta, and in the smooth muscle layer of the trachea and bronchioles. In the tracheal smooth muscle layer, connexin 37 overlapped with desmin-positive areas, but was clearly segregated from vimentin- and von Willebrand factor-positive areas. These results suggest that connexin 37 is expressed in smooth muscle cells in the trachea, but not in fibroblastic cells or endothelial cells. Connexin 37 was partially colocalized with connexin 43 in tracheal smooth muscle cells, and showed a gradual increase in expression during postnatal development. To our knowledge, this is the first report to be published regarding the expression of connexin 37 in smooth muscle cells.

Age Factors↗
PubMed1999

Antisense oligonucleotide of tissue inhibitor of metalloproteinase-1 induces the plasminogen activator activity in periodontal ligament cells.

BACKGROUND: Matrix metalloproteinases (MMPs), produced by both infiltrating and resident cells of the periodontium, play a role in physiologic and pathologic events. It is recognized that an imbalance between activated MMPs and their endogenous inhibitors leads to pathologic breakdown of the extracellular matrix during periodontitis. Although it is known that pro-MMPs are activated by the plasminogen activator (PA)/plasmin system, and that the activated MMPs are inactivated by tissue inhibitor of metalloproteinases (TIMPs), participation of TIMPs in the PA/plasmin system has not been defined. METHODS: We investigated the effects of the antisense oligonucleotide, consisting of a 21-base sequence from the human TIMP-1 gene including the first ATG initiation codon, on PA/plasmin activities in the cultured medium of periodontal ligament (PDL) fibroblastic cells. Antisense or sense oligonucleotides were directly added into cell-cultured medium, and enzyme activities from the PDL cells were measured. RESULTS: Antisense TIMP-1 oligonucleotide specifically stimulated the PA activity dose-dependently. Other oligonucleotides, sense TIMP-1 or antisense TIMP-2, did not affect PA activity in PDL cells. The PA activity increased by antisense TIMP-1 oligonucleotide was due to an increase of urokinase-type PA (uPA) protein, but not that of tissue-type PA by means of immunoblotting. Furthermore, the stimulation of PA activity in the conditioned medium by adding antisense oligonucleotide for TIMP-1 was not due to the decreasing levels of PA inhibitor-1, an inhibitor of PA. CONCLUSIONS: TIMP-1 controls the synthesis of uPA in the PDL cells. Control of the TIMP-uPA system is important in inflammatory periodontal ligament healing.

Analysis of Variance↗
PubMed1999

[The role of virulence factor of elastolytic proteinase from Aspergillus fumigatus].

The role of virulence factor of elastolytic proteinase produced by Aspergillus fumigatus was investigated in mice immunocompromised with cyclophosphamide (CY) to block neutrophil and lymphocyte functions or with carrageenan (CA) to block the phagocytic activity of macrophages. These mice were infected through inhalation with the spores of elastolytic proteinase producing or nonproducing strains of A. fumigatus, and then were observed daily for 15 days or until death. Compared to CY-immunocompromised mice treated with the spores of proteinase nonproducing strains, CY-immunocompromised mice treated with the spores of proteinase producing strains had a significantly shorter survival rate. Furthermore, when treated with the spores of proteinase producing strains, CA-immunocompromised mice survived significantly longer than did CY-immunocompromised mice. Assessment of the effect of elastolytic proteinase on rat lung showed that this enzyme induced hemorrhage of the lung, alveolar septal edema and alveolar hypertrophy due to blood neutrophil infiltration. Neither fusion nor denaturation of the elastic fiber was observed, however. These studies have suggested that when infected with A. fumigatus, a severe lesion in bronchioli or alveoli is induced by the proteinase producing strains, and that these strains are more virulent than the proteinase nonproducing strains.

Animals↗
PubMed1999

Detection of hepatitis B virus X-region DNA in liver tissue from patients with hepatitis C virus-associated cirrhosis who subsequently developed hepatocellular carcinoma.

The risk of hepatocellular carcinoma (HCC) in patients chronically infected by hepatitis C virus (HCV) is relatively higher in Japan than in Western countries. The presence of hepatitis B virus X (HBX)-DNA in the liver tissue samples obtained on enrollment from 69 patients with HCV-associated cirrhosis who were subsequently followed in our hospital was analyzed by polymerase chain reaction (PCR). During the follow-up period of 5.7+/-3.2 years (mean +/- SD), 52 (75%) of 69 patients developed HCC. The PCR analysis indicated that the HBX-DNA sequence was detected in 25 (48%) of 52 patients who developed HCC during follow-up, but in only 3 (18%) of 17 patients who did not (P<0.05). These results suggest that HBX, a hepatitis B viral product relevant to hepatocarcinogenesis, is involved in development of HCC in some patients chronically infected by HCV in Japan.

Adult↗
PubMed1999

[Clinical study of grade 3, superficial transitional cell carcinoma of the urinary bladder].

PURPOSE: To evaluate the treatment of grade 3 superficial (stage pTa and pT 1) transitional cell carcinoma (T.C.C.) of the urinary bladder, retrospective analysis was performed with special reference to tumor prognostic factors. MATERIALS AND METHODS: From July 1971 to september 1995, 51 cases with grade 3 superficial T.C.C. of the urinary bladder were treated. The survival rates and prognostic factors of these patient were analyzed. RESULTS: Five year survival rate of grade 3, superficial tumors was 92.3% and showed significantly better prognosis compared to patients with pT 2 and pT 3 tumors of grade 3 (p < 0.001). As a initial treatments, transurethral resection (TUR) was conducted in 45 patients (88%). Intravesical recurrence was observed in 20 of 45 patients (44%) and 12 of 20 patients (60%) were recurred within 1 year. Non-recurrent rates of the patients treated with TUR were 69.6% at 1 year, 58.8% at 3 year, 49.7% at 5 year, respectively. No significant differences were noted regarding factors of tumor size, figures and a number of tumor. Of the 51 patients, 10 (19.6%) progressed beyond stage T 2 and 6 died with the disease. Survival rates at 10 years follow up in patients with non-papillary and papillary tumor were 57.1% and 97.8%, respectively. CONCLUSION: These results suggested that TUR should be performed as a initial treatment for the patients with grade 3 superficial T.C.C. of the urinary bladder. However, non-papillary tumors should be considered of more intensive treatment like as radical cystectomy, adjuvant chemotherapy or irradiation.

Adult↗
PubMed1999

[Transient cortical blindness and convulsion mimicking a hemorrhagic complication during embolization of the cerebellar AVM].

We report a case of transient cortical blindness and convulsions during embolization of the cerebellar AVM. A 29-year-old man was admitted to our hospital with subarachnoid hemorrhage. Cerebral angiography showed the right cerebellar AVM fed by the right superior cerebellar artery. Preoperative embolization of the AVM was performed. During embolization, the patient lost consciousness suddenly and appeared to be in a decerebrate posture. About 15 minutes later, the patient came around and complained of total blindness. Cerebral angiography revealed the disappearance of the aneurysm and AVM. There were no abnormal findings in the vertebrobasilar system. Computed tomography obtained just after the procedure, showed considerable contrast enhancement of the occipital lobes. Two hours later, a repeat computed tomography showed clearance of contrast enhancement. Magnetic resonance imaging obtained 12 hours after the procedure, showed no evidence of infarction in the occipital lobes. Two days after, the patient's sight gradually returned. Seven days after the procedure, the patient recovered completely. We speculated that these clinical features might be convulsions due to contrast material. In the reported cases, convulsions and transient cortical blindness due to non-ionic low osmolar contrast materials is a rare complication. This case suggested disruption of the blood-brain barrier demonstrated by the computed tomography appearance of contrast enhancement in the occipital lobes.

Adult↗