Search PubMed⌕ Search

Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 271 records · Page 15Linked to original sources
PubMed1997

Rotational occlusion of the vertebral artery caused by transverse process hyperrotation and unilateral apophyseal joint subluxation. Case report.

The authors describe transverse process hyperrotation and unilateral apophyseal joint subluxation as a novel mechanism of rotational vertebral artery (VA) occlusion. The patient, a 56-year-old man, complained of episodic bilateral blindness when rotating his head more than 90 degrees to the right. Plain cervical x-ray films showed spondylotic osteophytes of the right C4-5 uncovertebral portion. Dynamic angiography revealed right VA occlusion at C4-5 and left VA occlusion at C1-2 with head rotation to the right. It was demonstrated on three-dimensional images constructed from computerized tomography scans that C-4 transverse process hyperrotation compressed the right VA against the apex of the C-5 subluxating superior articular process via the inner surface of the transverse process anterior root (processus costarius) rather than the osteophytes. It is also proposed that the true site of occlusion is different from that observed in angiographic studies.

Angiography↗
PubMed1997

Mitral regurgitation caused by mitral paraannular cyst.

A case of mitral regurgitation (MR) caused by mitral paraannular cyst is reported. A 37-year-old woman on maintenance hemodialysis was admitted to Akita University Hospital because of congestive heart failure. Echocardiography revealed mitral paraannular cyst, which caused coaptation failure of the mitral leaflets and significant MR. She underwent decapsulation of the cyst followed by mitral valve replacement. Postoperative echocardiography showed no recurrence of the cyst three years after surgery. Although mitral annular calcification has been described as a cause of MR in patients with uremia, a report of a solitary intracardiac cyst which causes significant MR is quite rare.

Adult↗
PubMed1997

Changes in the phosphorylation states of connexin43 in myoepithelial cells of lactating rat mammary glands.

Using specific antibodies and cDNA probe, we examined the expression pattern of a major gap junction protein, connexin43 (Cx43), in rat mammary glands during pregnancy and lactation. Double immuno-fluorescence revealed that the labeling of Cx43 was superimposed in the alpha-smooth muscle actin-positive cells, suggesting that myoepithelial cell were interconnected by gap junctions formed of Cx43. Just after delivery, the Cx43-labeled plaques were enlarged and increased in intensity. Northern and Western blot analyses confirmed the dramatic induction of Cx43 at both mRNA and protein levels on the day of parturition. Cx43 mRNA transcript immediately declined, while the increase of Cx43 protein continued for a few days. During pregnancy, immunoblots showed two bands of almost equal amounts at 43 and 45 kDa. Following delivery, the 45-kDa band gradually increased in intensity with a concomitant decrease of the 43-kDa band. From the sixth day of lactation, Cx43 was always detected as a single band at 45 kDa. Alkaline phosphatase treatment of immunoprecipitated Cx43 revealed that both bands represented phosphorylated forms, thus indicating that Cx43 was naturally phosphorylated and that it altered its phosphorylation states during lactation stages. These results suggest that the induction of Cx43 with the changes in the phosphorylation states plays an important role in the lactating function of myoepithelial cells in rat mammary glands. This is the first report on the changes of Cx43 phosphorylation states during physiological stages in vivo.

Amino Acid Sequence↗
PubMed1997

An acute myeloid leukemia gene, AML1, regulates transcriptional activation and hemopoietic myeloid cell differentiation antagonistically by two alternative spliced forms.

The AML1 gene on chromosome 21 is disrupted in the (8;21)(q22;q22) and (3;21)(q26;q22) translocations associated with myelogenous leukemias and encodes a DNA-binding protein. From AML1 gene, two representative forms of proteins, AML1a and AML1b, are produced by an alternative splicing. Both forms have DNA-binding domain, but AML1a lacks a putative transcriptional activation domain which AML1b has. Here we demonstrate that AML1a, which solely has no effects as a transcriptional regulator, dominantly suppresses transcriptional activation by AML1b, and that AML1a exhibits the higher affinity for DNA-binding than AML1b. Furthermore a dominant negative form of AML1, AML1a, totally suppressed granulocytic differentiation otherwise induced by granulocyte colony-stimulating factor when AML1a was overexpressed in 32Dc13 murine myeloid cells. Such differentiation block by AML1a was canceled by the concomitant overexpression of AML1b. These data strongly suggest that a transcriptionally active form of AML1 is essential for the myeloid cell differentiation. In addition, we observed an altered expression level of AML1 along with the myeloid differentiation in several hemopoietic cell lines. In these cases, at least, the AML1 expression level is a potential regulator for myeloid cell differentiation.

Alternative Splicing↗
PubMed1997

[Usefulness of directional coronary atherectomy as a bail-out device for acute closure after coronary angioplasty].

The usefulness of directional coronary atherectomy (DCA) as a bail-out device for acute closure (reclosure) after percutaneous transluminal coronary angioplasty (PTCA) was evaluated. PTCA was performed in 1,023 patients (182 with acute myocardial infarction) between January 1993 and January 1994 in our hospital. Thirty-one patients (11 with acute myocardial infarction) suffered acute closure (reclosure) after PTCA. In six patients (five with acute myocardial infarction), DCA was performed as a rescue treatment for acute closure (reclosure). In three of these patients, angioscopy was performed before DCA, which demonstrated intimal tear and some thrombi although coronary angiography showed no evidence of thrombus. Bail-out DCA was successful in all six patients without complications. DCA is useful as a bail-out device for acute closure (reclosure) after PTCA when the thrombus is not massive.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Epididymal sarcoidosis: a case report].

A rare case of epididymal sarcoidosis is reported. A 52-year-old man was admitted with a painless mass in the left scrotum. An operation revealed that a 1-cm mass was located at the epididymal head and well demarcated from the testis and the surrounding tissue. Epididymectomy was performed. Histopathological diagnosis was noncaseating granulomas consistent with sarcoidosis. Systemic examination showed bilateral hilar lymphadenopathy and bilateral peripheral anterior synechiae, but these lesions were diagnosed as inactive. Serum level of angiotensin-converting enzyme was normal.

Epididymis↗
PubMed1997

[Flow cytometric quantification of numerical chromosome aberrations in non-small cell lung carcinomas using formalin-fixed paraffin-embedded tissue].

Fluorescence in situ hybridization with biotinylated repetitive DNA probe specific for the centromeric region of chromosome 17 (p17H8: Oncor) was applied to suspended nuclei which were isolated by Shutte's method from formalin-fixed paraffin-embedded tissue. The tissues were obtained from surgically resected specimens from nine patients with non-small cell lung carcinoma. The isolated nuclei were prepared with 0.05% pepsin/0.1NHCl for 15 minutes at 37 degrees C. Subsequently, these were immersed in 70% acetic acid for 10 seconds at room temperature. After heat denature with hybridization mixture which contained 3 mu 1 DNA probe for 10 minutesat 70 degrees C, 1 x 10(6) nuclei were incubated overnight at 37 degrees C. After washing with 60% formamide/2 x SSC, the hybridized probes were labeled by FITC conjugated avidin. A number of centromeric signals of chromosome 17 wasevaluated by fluorescence microscopy (BH-2, Olympus). Furthermore, a probe-related FITC intensity was quantified using flow cytometry (FACScan, Becton Dickinson). As the results, there was good correlation between a relative fluorescence intensity determined by flow cytometry and a relative fluorescence signal by fluorescence microscopy (p < 0.05).

Aged↗
PubMed1996

Functional expression of CD11a on CD8+ cells is suppressed in regional lymph nodes with cancer involvement in patients with gastrointestinal carcinoma.

BACKGROUND: To evaluate the immunologic activity of regional lymph nodes, the phenotype of lymphocytes and the functional expression of cell adhesion molecules (CAMs) on lymph node lymphocytes (LNL-: uninvolved, LNL+: involved) were investigated in patients with gastrointestinal carcinoma. METHODS: The lymphocyte subpopulation and the expression of CD11a, CD44, and CD29 on CD4+ and CD8+ cells in peripheral blood lymphocytes (PBL), LNL- and LNL+ derived from 37 patients with gastrointestinal carcinoma were studied. In addition, the adherence of CD8+ cells to ICAM-1 which reflects the adhesive function of CD11a, was examined, and changes in this adherence were studied by experimental coculture with cancer cells (DLD-1). RESULTS: Although there were no differences in the overall proportion of T cells between the groups, CD8+ cells and CD16+ cells were considerably diminished in LNL+. The expression of CD11a and CD29 on CD4+ and CD8+ cells was significantly lower in LNL than in PBL, whereas the expression of CD44 showed no significant differences. The expression levels of these CAMs were almost the same in LNL- and LNL+. Only CD11a expression on CD8+ cells in LNL+ was significantly lower than that in LNL- (P < 0.005). The adherence of CD8+ cells in LNL+ to ICAM-1 was lower than that in PBL and LNL-, and was extremely enhanced by experimental coculture with cancer cells (DLD-1). CONCLUSIONS: These data indicate that the functional expression of CD11a (LFA-1) on CD8+ T cells is suppressed in cancer-involved regional lymph nodes in patients with gastrointestinal carcinoma.

Adenocarcinoma↗
PubMed1996

Molecular and genetic analysis of multiple changes in the levels of production of virulence factors in a subcultured variant of Streptococcus mutans.

We previously isolated a variant strain, Xc100L, which shows decreased production of a surface protein antigen with a molecular mass of 190 kDa (PAc), after repeated subculturing of Streptococcus mutans strain Xc [Koga, T. et al. (1989) J.Gen. Microbiol. 135, 3199-3202]. In the present study, the levels of expression of the gtfB, gtfC, gtfD and ftf genes coding for polysaccharide-synthesizing enzymes in strain Xc100L were compared with those in strain Xc. Western blot analysis revealed multiple differences in the levels of production of these enzymes between these two strains. The amounts of the gtfB and gtfC gene products responsible for water-insoluble glucan synthesis in strain Xc100L were lower than those in strain Xc, whereas the amounts of the gtfD and ftf gene products responsible for water soluble glucan synthesis and fructan synthesis, respectively, in strain Xc100L were higher than those in strain Xc. Northern blot analysis revealed that the amounts of the four enzymes and PAc produced by strain Xc100L reflected the relative amounts of mRNAs from the genes. The chloramphenicol acetyltransferase gene was fused with each of these five genes, and the transcriptional activity of each gene in strain Xc100L was quantitatively compared with that in strain Xc. The chloramphenicol acetyltransferase assay also indicated that the phenotypic differences between strain Xc and strain Xc100L were due to differences in the transcriptional activities of the virulence genes. No differences in the nucleotide sequences of the promoter regions of the gtfB, gtfC, gtfD, ftf and pac genes were found between strain Xc and strain Xc100L. It is possible that a factor(s) affecting the levels of transcription of the multiple virulence genes exists in S. mutans.

Antigens, Bacterial↗
PubMed1996

Identification of the Streptococcus mutans frp gene as a potential regulator of fructosyltransferase expression.

Four putative open reading frames (ORFs) were previously identified in the regions flanking the Streptococcus mutans GS-5 fructosyltransferase (FTF) gene. One of these, ORF 3, appeared to code for a low-molecular-mass protein containing amino acid sequences sharing homology with several Gram-positive bacterial DNA-binding proteins and it was suggested that the ORF 3 gene product might be an FTF regulatory protein (FRP). In order to characterize this protein, we have purified the biotinylated tag-FRP fusion protein using the PinPoint protein purification system and this fusion protein was used in gel shift assays with DNA fragments containing the ftf promoter region. FRP bound specifically to the upstream region of the ftf promoter containing the inverted repeat structure that is present upstream of the -35 sequence. In contrast, FRP did not bind to DNA fragments lacking the inverted repeat structure. The results of these experiments suggest that FRP interacts with the inverted repeat region upstream of the ftf promoter and such interactions may regulate FTF expression.

Amino Acid Sequence↗
PubMed1996

In vitro senescence enhances IL-6 production in human gingival fibroblasts induced by lipopolysaccharide from Campylobacter rectus.

The production of interleukin-6 (IL-6) in human gingival fibroblasts (Gin cells) is increased by lipopolysaccharide (LPS) from Campylobacter rectus (C. rectus), which is associated with adult periodontitis; however, the age-related changes in the susceptibility of Gin cells to C. rectus LPS remain unclear. We examined the influence of in vitro senescence on C. rectus LPS-stimulated IL-6 production in Gin cells. LPS was prepared from C. rectus ATCC 33238 using hot phenol-water. The Gin cells were established from healthy gingival tissue removed from three patients, aged 10-12 years. The cells were cultured until confluence then stimulated with LPS (0.01, 0.1, 1.0 and 10.0 micrograms/ml). Levels of IL-6 released in the medium were measured after incubation for 3, 6, 9, 12, and 24 h. In both young (5-6 population doublings) and senescent (17-20 population doublings) cells, LPS stimulated IL-6 production in a dose- and time-dependent manner. In response to 0.01-10.0 micrograms/ml of LPS, IL-6 production in the senescent cells was higher than that in the young cells. Using cells from each of the three donors, we found that this phenomenon of higher LPS-stimulated IL-6 production in senescent cells was reproducible. The greater capacity of the senescent cells to synthesize IL-6 in response to LPS was a higher production of mRNA for IL-6. This increase of IL-6 production induced by C. rectus LPS in senescent Gin cells could help to explain the increased susceptibility to periodontal diseases shown by aged individuals.

Adult↗
PubMed1996

Cellular detachment and deformation induce IL-8 gene expression in human bronchial epithelial cells.

Neutrophil elastase (NE) is known to be one of the most potent proteases capable of deforming and detaching human bronchial epithelial cells (BECs) and inducing IL-8 gene expression. However, mechanisms of NE-induced IL-8 gene expression are unclear, especially with respect to how they relate to cellular detachment. To elucidate these mechanisms, effects of cell detachment and deformation following mechanical injury or pharmacologic stimuli on IL-8 gene expression were examined by Northern analyses. When BET-1A cells from a human bronchial epithelial cell line were incubated with NE (100 nM), trypsin (0.5 mg/ml), EGTA (7 mM), or EDTA (0.7 mM) to induce deformation and detachment, IL-8 mRNA transcript levels were up-regulated, as demonstrated in a case of mechanical detachment from the culture plate using a cell scraper. This IL-8 gene expression was inhibited by pretreatment with 5 microM taxol, a microtubule-stabilizing agent. Colchicine or vinblastine, microtubule-disrupting agents, induced IL-8 gene expression, which was also inhibited by taxol treatment. These data suggest that structural changes, including deformation of the cytoskeleton, especially microtubules, may contribute to IL-8 gene expression in human BECs. Since detachment and cellular deformation of BECs caused by proteases have been observed frequently in a variety of inflammatory airway diseases, our findings provide evidence that detached or deformed BECs potentially enhance production of inflammatory mediators in the pathogenesis of airway inflammation.

Base Sequence↗
PubMed1996

Histopathological characteristics of childhood thyroid cancer in Gomel, Belarus.

We reviewed histopathologically 19 cases of childhood thyroid cancer occurring between 1991 and 1994 among 14,396 screening subjects in Gomel, Republic of Belarus, the region most severely radio-contaminated by the Chernobyl nuclear power plant accident in 1986. The patients were 13 girls and 6 boys with a mean age of 10.6 years. The mean age at the time of the accident was 3.2 years. Mean tumor diameter was 16 mm, and all cases were papillary carcinoma with various amounts of solid component. Psammoma bodies and stromal fibrosis were encountered to some extent in almost all cases. The tumors were highly prone to local invasion and regional lymph-node metastasis. No morphological evidence for radiation-induced cancer was obtained in these cases. 137Cs levels were relatively high in the patients' bodies and in the soil at the places of domicile. However, there was no dose-response relationship between cancer prevalence and radioactivity. These facts suggest that the incidence of aggressive pediatric thyroid cancer is extremely high in Gomel, where most of the children were exposed to a low level of radioactivity over a long time after the accident. At present, however, no definite conclusion can be drawn on the relationship between cancer occurrence and radioactive contamination.

Accidents↗
PubMed1996

Stimulation of interleukin-1beta-converting enzyme activity during growth inhibition by CPT-11 in the human myeloid leukemia cell line K562.

Camptothecin (CPT) was first extracted from Camptotheca acuminata and has a strong antitumor effect. Its water-soluble derivative, CPT-11, has higher therapeutic efficacy and less toxicity than CPT. Recently, CPT-treated cells have been shown to undergo apoptosis. However, the mechanism of induction of apoptosis by CPT has not been characterized in detail in any type of cells. On the other hand, interleukin-1beta-converting enzyme (ICE) is a mammalian homologue of CED3, a protein required for apoptosis in the nematode Caenorhabditis elegans. To determine how CPT-11 brings about cell death by apoptosis, we investigated the effects of CPT-11 on the expression of ICE activity in K562 cells, which represent human myeloid leukemia cells. The proliferation of K562 cells was shown to be inhibited by the presence of CPT-11 in the culture medium. We also found that the levels of mRNA for ICE in the cells were increased in the presence of CPT-11. Furthermore, we demonstrated that when CPT-11 was added to the culture medium, apoptosis of K562 cells was clearly detected in situ. These features suggested that CPT-11 enhances the apoptotic cell death in K562 cells and that a part of induction of apoptosis by CPT-11 may be correlated with the stimulation of the ICE activity.

Apoptosis↗
PubMed1996

Stimulation of interleukin-1beta-independent interleukin-6 production in human dental pulp cells by lipopolysaccharide.

Dental pulpal infection is most commonly caused by extensive dental caries. A principal driving force behind pulpal disease response appears to lie in the immune system's response to bacteria. However, the production of interleukin (IL)-1beta and IL-6 in human dental pulp (HDP) cells in response to lipopolysaccharide (LPS) has not been well characterized. We examined IL-1beta and IL-6 production in HDP cells by challenging with LPS from Porphyromonas endodontalis, which is a Gram-negative bacteria found in root canals. Our results presented here showed that when HDP cells were stimulated by LPS, the production of IL-6 always preceded that of IL-1beta. Since the IL-6 production was observed even in the presence of the IL-1beta receptor antagonist, we concluded IL-6 production was independent of the IL-1beta molecule in LPS-stimulated HDP cells. This idea was further supported by the results obtained from RT-PCR experiments, in which IL-6 mRNA, but not IL-1beta mRNA, was present in the RNA preparation isolated from the early stage of cells.

Cells, Cultured↗