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Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 307 records · Page 17Linked to original sources
PubMed1996

Enhancement of the expression of progesterone receptor on progesterone-treated lymphocytes after immunotherapy in unexplained recurrent spontaneous abortion.

PROBLEM: The immunological mechanism of an effective immunotherapy with paternal lymphocytes for unexplained recurrent spontaneous abortion (RSA) is not yet clear. Previous studies revealed that progesterone plays an important role in maintaining normal pregnancy and lower expression of progesterone receptor (PGR) on lymphocytes was found in RSA. Therefore, it was of interest to investigate whether immunotherapy for RSA would be able to enhance the expression of PGR on lymphocytes of RSA. METHOD: PGR expression on lymphocytes was analyzed with indirect immunofluorescence using flow cytometry. RESULTS: There was no change of PGR expression on PBL of RSA between pre- and post-immunotherapy (P > 0.05), while in the presence of 10.0 micrograms/ml progesterone for 24 h, PGR expressed on PBL on post-immunotherapy was increased significantly as compared with that of pre-immunotherapy in successful cases (P < 0.05) and decreased in abortive cases (P < 0.05). Most PGR was expressed on both CD4+ and CD8+ lymphocyte subsets. In successful cases, CD8+PGR+ subset of post-immunotherapy was found to be increased significantly (P < 0.05) in comparison with that of pre-immunotherapy. CONCLUSION: The data in the present study suggest that immunotherapy for RSA induced a higher expression of PGR on progesterone-treated lymphocytes, which may be involved in successful pregnancy.

Abortion, Habitual↗
PubMed1996

Binding of hemoglobin to the envelope of Porphyromonas gingivalis and isolation of the hemoglobin-binding protein.

The binding activity of the Porphyromonas gingivalis envelope and hemoglobin was examined over a wide range of pH values from 4.5 to 9.0. The binding activity in low-pH buffers was much higher than that at high pH; the optimum pHs for the binding were found to be 4.5 and 5.0. Since the hemoglobin bound to the envelope was found to dissociate in the pH 8.5 and 9.0 buffers, the binding is reversible. We hypothesized that hemoglobin-binding protein (HbBP), responsible for the binding to hemoglobin, exists in the envelope and confirmed its presence by dot blot determination with peroxidase-conjugated hemoglobin. Then we attempted to isolate HbBP from the solubilized (by a detergent) materials of the envelope by affinity chromatography. The molecular mass of HbBP was 19 kDa, and the isoelectric point was 4.3.

Bacterial Proteins↗
PubMed1996

The extracellular signal-regulated kinase pathway phosphorylates AML1, an acute myeloid leukemia gene product, and potentially regulates its transactivation ability.

AML1 (also called PEBP2alphaB, CBFA2, or CBFalpha2) is one of the most frequently disrupted genes in chromosome abnormalities seen in human leukemias. It has been reported that AML1 plays several pivotal roles in myeloid hematopoietic differentiation and other biological phenomena, probably through the transcriptional regulation of various relevant genes. Here, we investigated the mechanism of regulation of AML1 functions through signal transduction pathways. The results showed that AML1 is phosphorylated in vivo on two serine residues within the proline-, serine-, and threonine-rich region, with dependence on the activation of extracellular signal-regulated kinase (ERK) and with interleukin-3 stimulation in a hematopoietic cell line. These in vivo phosphorylation sites of AML1 were phosphorylated directly in vitro by ERK. Although differences between wild-type AML1 and phosphorylation site mutants in DNA-binding affinity were not observed, we have shown that ERK-dependent phosphorylation potentiates the transactivation ability of AML1. Furthermore the phosphorylation site mutations reduced the transforming capacity of AML1 in fibroblast cells. These data indicate that AML1 functions are potentially regulated by ERK, which is activated by cytokine and growth factor stimuli. This study provides some important clues for clarifying unidentified facets of the regulatory mechanism of AML1 function.

Acute Disease↗
PubMed1996

Identification of rab12 as a secretory granule-associated small GTP-binding protein in atrial myocytes.

A subfamily of small GTP-binding proteins, rab, has been shown to be involved in regulation of vesicular traffic in eukaryotic cells. The goal of this study was to identify the rab proteins associated with atrial secretory granules. A [32P]GTP-overlay assay showed the presence of multiple small GTP-binding proteins on the atrial granules. By biochemical analysis, we have demonstrated that one of the small GTP-binding proteins associated with the atrial granules is a rab12 protein (rab12p), one of the rab proteins that are most closely related to a Sec4 protein of yeast. Association of rab12p with the atrial granules was confirmed by immunogold electron microscopy. Immunoprecipitation followed by immunoblot analysis with anti-rab12 antibody showed that in addition to atria, rab12p was expressed in multiple other organs and cell lines. These results suggest that rab12p may function in vesicular traffic in multiple diverse types of cells.

Animals↗
PubMed1996

Effects of different magnitudes of tension-force on alkaline phosphatase activity in periodontal ligament cells.

Alkaline phosphatase (ALP) activity is involved in the process of calcification in various mineralizing tissues, and it is found at much higher levels in the periodontal ligament (PDL) than in other connective tissues. Since the PDL lies between hard tissues and functions as a cushion mitigating mechanical stress, such as occlusal and orthodontic forces, this stress may modulate ALP activity in PDL cells, which themselves may affect adjacent alveolar bone metabolism. The objective of this study was to determine the level of ALP activity and the gene expression of liver/bone/kidney (L/B/K) ALP in human PDL fibroblasts in response to cyclic tension-forces. Human PDL cells were cultured on flexible-bottomed plates and placed on a Flexercell Strain Unit. Cells were flexed at 6 cycle/min (5 sec strain, 5 sec relaxation) at 6 levels of tension-force (9%, 12%, 15%, 18%, 21%, and 24% increase in surface area) for 5 days. There was no significant difference in cell proliferation between the cells subjected to the tension-force and the controls. There was a 10% and 42% decrease, respectively, in the ALP activity in PDL cells exposed to low (9%) and high (24%) tension-forces, and these decreases were dependent on the magnitude of the tension-force. The finding of inhibited ALP activity in response to tension-force was consistent with the observation that L/B/K ALP mRNA levels were decreased in response to cyclic tension-force. These results suggest that tension-force may affect PDL metabolism, depending on the functional role of ALP.

Alkaline Phosphatase↗
PubMed1996

Tumour necrosis factor receptor gene expression and shedding in human whole lung tissue and pulmonary epithelium.

This study aimed to investigate the expression of tumour necrosis factor receptor (TNF-R) at the gene and surface level, and its shedding in human lung tissue and a pulmonary epithelial cell line, A549. Levels of gene expression of TNF-R were evaluated by Northern blot analysis. Human lung tissue expressed both type I and type II TNF-R gene, while A549 cells expressed only type I TNF-R gene. Phorbol ester upregulated and TNF-alpha down-regulated the TNF-R gene expression in A549 cells. Consistent with these modulations of TNF-R gene expression, 125I-TNF binding capacities were increased with phorbol ester stimulation and decreased with TNF stimulation after 24 h in A549 cells. The shedding of TNF-R from A549 cells was investigated using enzyme-linked immunosorbent assay (ELISA) for soluble type I TNF-R. Not only lung tissues but also A549 cells spontaneously released soluble type I TNF-R into the culture medium. Both phorbol ester and TNF stimulation accelerated the shedding of soluble TNF-R from A549 cells. These results suggest that type I TNF-R gene expression and shedding of soluble TNF-R are differentially regulated in A549 cells. We conclude that tumour necrosis factor receptor surface expression is regulated, at least in part, at the gene expression level and shedding of soluble tumour necrosis factor receptor is modulated by inflammatory mediators, such as tumour necrosis factor in A549 cells.

Analysis of Variance↗
PubMed1996

Augmentation by phthalimides of phorbol ester-induced expression of tumor necrosis factor alpha message.

N(alpha)-Phthalimidoglutarimide (thalidomide), 2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (PP-33) and its 4,5,6,7-tetrafluoro derivative (FPP-33) augmented 12-O-tetradecanoylphorbol 13-acetate-induced production by human leukemia HL-60 cells of both tumor necrosis factor alpha (TNF-alpha) mRNA and secreted TNF-alpha protein. Intracellular TNF-alpha protein production was increased to a lesser extent.

Blotting, Northern↗
PubMed1996

Phenylphthalimides with tumor necrosis factor alpha production-enhancing activity.

Phenylphthalimides (2-phenyl-1H-isoindole-1,3-diones) were prepared and their effects on tumor necrosis factor alpha (TNF-alpha) production by human leukemia cell line HL-60 stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA) were examined. An analysis of the structure-activity relationships of the phenylphthalimides indicated that potent enhancing activity on TPA-induced TNF-alpha production by HL-60 cells requires medium-sized substituent(s) at the ortho position(s) of the phenyl group; 2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (PP-33) increased the TNF-alpha production to more than 600% at the concentration of 1 x 10(-5) M. Introduction of a nitro group at the phthalimide moiety of PP-33 enhanced the activity; 2-(2,6-diisopropylphenyl)-4-nitro-1H-isoindole-1,3-dione (4NPP-33) and its 5-nitro isomer (5NPP-33) enhanced the TNF-alpha production to more than 800% and 700%, respectively, at the concentration of 1 x 10(-5) M. Introduction of fluorines into the phthalimide moiety of PP-33 greatly lowered the concentration of the compound necessary to elicit the TNF-alpha production-enhancing activity; 2-(2,6-diisopropylphenyl)-4,5,6,7-tetrafluoro-1H-isoindole-1,3-dio ne (FPP-33) showed the activity at nanomolar concentration, with the optimum concentration of 1 x 10(-7) M.

HL-60 Cells↗
PubMed1996

Ultrastructure of the cyst wall of Sarcocystis species with canine final host in Japan.

The ultrastructural characteristics of cyst wall are a useful clue to the identification of Sarcocystis species. Among the eight species examined, S. cruzi, S. sp. 1 from sheep and S. hircicanis had the thin cyst wall with long, tapered hair-like villar protrusions. The protrusions arose from the dome-like bulges of cyst wall and ran parallel to the surface. No clear ramification was observed in the tip of protrusion of these three species. S. tenella, S. capracanis, S. miescheriana, S. fayeri, and S. sp. 2 from Japanese deer had the thick cyst wall. The villar protrusions of the former three species were palisade-like in shape, but those of S. tenella and S. Capracanis were slightly thinner than those of S. miescheriana. The villar protrusions of S. fayeri and S. sp. 2 were finger-like, but those of the former species were shorter and thicker than those of the latter species. S. fayeri had many minute depressions on the surface of protrusion in a reticular pattern. Microtubules in the core of protrusion were seen in S. miescheriana, S. fayeri and S. sp. 2 but not in the other species. Microdepressions were observed on the surface of cyst wall among the protrusions in all the Sarcocystis species examined, but their function was not made clear.

Animals↗
PubMed1996

Colocalization of connexin 43 and connexin 45 but absence of connexin 40 in granulosa cell gap junctions of rat ovary.

The expression and localization of gap junction family proteins (connexins) were examined in nonstimulated and gonadotrophin-stimulated ovarian follicles of immature rats. Immunoblot and RNA blot analysis showed the presence of connexin (Cx) 43, Cx40 and Cx45 in ovarian tissue. Of these connexin proteins, Cx43 and Cx45 were identified by immunofluorescent microscopy between granulosa cells in characteristic expression patterns related to follicular developmental stages, while Cx40 was not expressed in granulosa cells but was detected in blood vessels in ovarian stroma. In some plaques of gap junction between granulosa cells, Cx45 was found to be colocalized with Cx43. In immunofluorescent microscopy, the expression of Cx43 was increased with follicular growth, but decreased after induction of ovulation by injection of human chorionic gonadotrophin. In contrast, the Cx45 protein was constantly expressed through follicular development; however, after ovulation, no staining of Cx45 was detected in the corpus luteum. Dual expression and the functional role of Cx43 and Cx45 in cell-to-cell communication in ovarian granulosa cells at various developmental stages were discussed.

Animals↗
PubMed1996

Autoantibodies and immunoglobulins in atomic bomb survivors with human T-lymphotropic virus type I.

The association of human T-lymphotropic virus type I (HTLV-I) with autoimmune disorders was investigated on the basis of prevalence of antinuclear antibody (ANA), rheumatoid factor and anti-thyroglobulin antibody as well as immunoglobulin (Ig) serum level (IgG, IgA, and IgM). The subjects, all atomic bomb survivors, were 59 HTLV-I-seropositive people without HTLV-I-associated myelopathy or adult T-cell leukemia and 149 HTLV-I-seronegative persons. The mean serum level of IgM was higher in HTLV-I-seropositive subjects than in HTLV-I-seronegative subjects, and a significant association with HTLV-I and sex was indicated in the IgM serum level. No association with HTLV-I was indicated in the prevalence of the autoantibodies except for ANA. These results suggest some clear humoral immunity differences between HTLV-I-infected and noninfected subjects, but whether HTLV-I infection can lead to autoimmune disorders remains uncertain.

Adult↗
PubMed1996

Low grade astrocytoma in the medial part of the frontal lobe manifesting as paroxysmal speech disturbance--case report.

A right-handed 48-year-old female had clustered groups of seizures characterized by speech disturbance (attacks of verbal repetition and speech arrest) over a period of 7 years. Later, speech arrest was accompanied by perioral focal seizures. Magnetic resonance imaging and surgery found a low grade astrocytoma, centered in the left supplementary motor area. Postoperatively, no seizures or speech disturbances occurred for 3 years. This case confirms the main function of the supplementary motor area of the dominant hemisphere is connected with the initiation of speech and the setting into motion of the mechanism of speech.

Astrocytoma↗
PubMed1996

Content and characteristics of vitamin B12 in some seaweeds.

The vitamin B12 (B12) content in seven species of seaweed that are consumed frequently in Hokkaido, Japan, was microbiologically measured using Escherichia coli 215. Asakusanori (Porphyra tenera), maruba-amanori (Porphyra suborbiculata) and akaba-gin-nansou (rhodo-glossum pulcherum) showed higher B12 content than the other species, although the content varied greatly among samples in the same species. A bioautography on a thin-layer plate holding a mixture of silica gel and cellulose, differentiation of B12 and its analogues using a binding specificity of intrinsic factor and haptocorrin, and comparison of the B12 concentration determined by the radioisotope dilution assay method using the intrinsic factor as the B12-binding protein with that by the bioassay method, predominantly showed B12 in maruba-amanori and B12 analogues in wakame (Undaria pinnatifida) and akaba-gin-nansou. The B12 uptake of akaba-gin-nansou from artificial seawater was similar to that of asakusanori that contained only B12.

Chromatography, Thin Layer↗
PubMed1996

[A case of solitary metastasis from renal cell carcinoma to the thyroid gland].

A case of solitary metastasis with renal cell carcinoma to the thyroid gland is presented. The patient was a 54-year-old man found to have an abnormal mass in the neck. He had a past history of radical nephrectomy orignating from the right renal cell carcinoma 5 years earlier (pT2N0M0, G2 > 3, alveolar type, clear cell subtype). Ultrasonography revealed a tumor mass in the right hemithyroid gland. Right hemithyroidectomy was performed on April 19, 1995. Histopathologically, the removed thyroid tumor showed clear cell carcinoma. The possibility of a primary thyroid tumor was ruled out by immunohistochemical thyroglobulin staining, and the present case was thus diagnosed as of metastatic thyroid tumor of renal cell carcinoma. The present case is the 12th case of thyroid solitary metastasis of renal cell carcinoma reported in Japan to date.

Carcinoma, Renal Cell↗
PubMed1996

[Aortic root replacement employing Cabrol and Piehler techniques].

Between February, 1982, and September, 1994, 24 patients underwent aortic root replacement using a valve-bearing composite graft and coronary perfusion grafts. The indications for surgery were annulo-aortic ectasia in 21 patients, and aortic dissection associated with significant aortic regurgitation in 3 patients. Aortic root was reconstructed employing the techniques described by Cabrol and colleagues (Cabrol operation) in 16, and by Piehler and Pluth (Piehler operation) in 8. Two of 16 patients who underwent Cabrol operation required concomitant procedures. Four patients (25.0%) who underwent Cabrol operation had technical troubles relating to coronary reattachements (kinking and torsion of coronary grafts in 2, obstruction of left limb of coronary graft in 1, and coronary graft compression by aortic wall wrapping in 1), while one patient (12.5%) having Piehler operation had coronary graft compression by partial wrapping of aortic root. The hospital deaths occurred in 4 patients undergone Cabrol operation, with the hospital mortality rate being 16.7%. Three patients including 2 with concomitant procedures died of low cardiac output and one died of rupture of residual dissecting aneurysm of the aortic arch. No pseudoaneurysm nor anastomotic stenosis was observed in any hospital survivors. Late deaths occurred in 5 patients, in whom there was no late complication relating to coronary reconstruction. However, late obstruction of left ostial stenosis developed in one patient who underwent Piehler operation, which required coronary artery bypass. We conclude that aortic root replacement using coronary perfusion grafts provides sound coronary anastomoses without late pseudoanurysm. Coronary reattachments is facilitated by use of Piehler technique, preventing coronary graft kinking or torsion. Late coronary ostial stenosis should be considered as a possible cause of fatal myocardial infarction and sudden death, and careful follow-up is required for patients having these kinds of operation for the prevention of late cardiac events.

Adult↗
PubMed1996

p53-independent induction of apoptosis by cyclin-dependent kinase inhibition.

The G1 checkpoint and terminal differentiation may be associated with apoptosis, the induction of which is in large part dependent on the presence of active p53. However, cells lacking wild-type p53 can undergo apoptotic cell death during normal development and during terminal differentiation of malignant cells. Using the specific inhibitor for cyclin-dependent kinases (cdks), we show here that an inhibition of cdk activity per se can induce apoptotic cell death during G1-S transition of the cell cycle in a p53-independent manner. The apoptotic process triggered by cdk inhibition was associated with an overriding of the G1-S boundary and was inhibited by arresting the cells in G1. These results raise the possibility that aberrant cell cycle machinery may result in self-elimination, even in the absence of p53, and further indicate that cdk activity is not necessarily required during this process.

4-Butyrolactone↗
PubMed1996

[Nonrheumatic calcification of the mitral valve in patients with stenotic calcified bicuspid aortic valve].

The pathogenesis of nonrheumatic calcification of the mitral valve was investigated by analyzing the clinical and echocardiographic characteristics of patients with mitral valvular calcification without any findings suggestive of rheumatic heart disease or infective endocarditis. Calcification of the mitral valve was observed in nine patients, who all had calcified stenotic (aortic valve area < 1 cm2) bicuspid aortic valve. Calcification of the mitral valve was localized to the basal portion of ventricular aspect of the anterior mitral leaflet and contiguous to that of the aortic valve. Mobility and thickness of the mitral leaflet was normal except for the calcified portion. Calcification of the mitral valve was not contiguous to posterior mitral annular calcification nor was related to direction of aortic regurgitant flow. In patients with calcified stenotic bicuspid aortic valve, calcification of the mitral valve was not associated with location of the two aortic cusps, aortic valve area, aortic valvular peak pressure gradient, direction of the left ventricular outflow, end-diastolic left ventricular outflow tract dimension, end-diastolic dimension of the aortic annulus, incidence of aortic regurgitation, calcification of the aortic arch, or risk factors of atherosclerosis. Six patients with mitral valvular calcification had aortic valve replacement. Preoperative coronary angiogram of these patients was normal. Calcification of the aortic valve was on the ventricular and aortic aspects. The calcification of the aortic valve, anterior mitral ring, or anterior mitral leaflet was not rheumatic in these six patients. Rheumatic disease, risk factors of atherosclerosis, mechanical stress by left ventricular outflow or aortic regurgitant flow, or mitral annular calcification did not appear to be related to mitral valvular calcification. The distribution of aortic and mitral valvular calcification suggested that the calcification of the mitral valve was due to progression of calcification of the bicuspid aortic valve.

Aged↗