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Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 235 records · Page 13Linked to original sources
PubMed1994

[A case of aortic valve-regurgitation associated with Behçet's disease].

The patient was a 37-year-old female with incomplete form of Behçet's disease combined with aortic valve regurgitation. The patients with Behçet's disease often have perivalvular leakage after valve replacement. Special technique is necessary in order to reinforce suture lines and minimize the occurrence of postoperative perivalvular leakage. The aortic valve replacement was accomplished by bolstering mattress sutures with Teflon felt strips and by inserting of sutures from outside the aorta. The latter technique was utilized around the entire circumference of the aortic annulus by opening the right ventricular outflow tract and right atrium and passing sutures from within these structures to enter the aorta. Satisfactory result was obtained with no findings of perivalvular leakage 2 years after operation. The conductive system was not damaged. The operation was performed when the inflammatory signs and findings subsided with adrenal steroids. The steroid therapy has been continued and adjusted by the values of CRP as well as the cutaneous and mucous manifestations.

Adult↗
PubMed1993

Ligand-induced conformational changes modify proteolytic cleavage of the adipocyte insulin-sensitive glucose transporter.

The transport conformation of the human erythrocyte glucose transporter (GLUT1) modifies rates of proteolytic cleavage of this protein by a variety of enzymes. We investigated the effects of ligand-induced conformational change on the susceptibility to enzymic cleavage of the insulin-sensitive rat adipocyte glucose transporter (GLUT4). A GLUT4-enriched slow sedimenting microsomal fraction was prepared from basal adipocytes and subjected to PAGE and immunoblotting. The GLUT4 protein was detected in these immunoblots with a C-terminal-specific antiserum as an M(r)-46,000-50,000 doublet. GLUT1 protein was not detected by a GLUT1-specific antiserum in these membranes. Tryptic digestion caused loss of the GLUT4 signal in immunoblots in a time- and concentration-dependent fashion. Low-M(r) membrane-bound fragments were not observed in electrophoretic gels, whether detection was attempted by immunoblotting or by counting radioactivity in gel slices following photolabelling with [3H]cytochalasin B. Transport-specific ligands known to induce an outward-facing conformation in the human erythrocyte GLUT1 protein retarded cleavage of the GLUT4 protein by submaximal concentrations of trypsin, whereas ligands known to induce an inward-facing conformation increased the extent of cleavage. The transported substrate D-glucose retarded tryptic cleavage of GLUT4. This result contrasts with the known behaviour of GLUT1, in which D-glucose accelerates cleavage. Cleavage of GLUT4 by thermolysin was also retarded by the outward-binding analogue 4,6-O-ethylidene glucose. These results show that the conformational sensitivity to proteolysis of GLUT4 mirrors that of GLUT1, except that the glucose-loaded GLUT4 has a different steady-state configuration, which may reflect underlying kinetic differences between the two proteins.

Adipocytes↗
PubMed1993

The effects of calpeptin (a calpain specific inhibitor) on agonist induced microparticle formation from the platelet plasma membrane.

Platelets activated by various agonists produce formation of vesicles shed from the plasma membrane (microparticles). However, the mechanism of microparticle (MP) formation has not been clarified yet. The aim of the present study was to determine the possibility of involvement of calpain (a Ca(2+)-dependent thiol protease) in MP formation. Washed platelets preincubated with calpeptin, a cell permeable calpain specific inhibitor, or with a vehicle were activated by thrombin plus collagen or by calcium ionophore A23187. Flow cytometry was used to detect the amount of microparticle formation by using murine monoclonal antibodies against GP IIb-IIIa or GP IIb and fluorescein 5-isothiocyanate labeled goat anti-mouse IgG. MP formation stimulated either by thrombin plus collagen or by A23187 was inhibited by calpeptin in a dose dependent manner. The microparticle formation from platelets activated by A23187 reached a plateau in approximately 5 min after activation, whereas that from platelets activated by thrombin plus collagen reached a plateau at 30 min following the stimulation. These time sequences corresponded well with those of degradation of actin-binding protein (ABP), a well known substrate of calpain, of platelets activated by these two stimulations. However, the inhibition of MP formation by calpeptin was more marked in the early stage (within 10 min) than in the late stage (after 30 min) of platelet activation. At 30 min after platelet activation by either two stimulations, a significant amount of microparticle formation was observed in the presence of 30 microM calpeptin, which inhibited hydrolysis of ABP almost completely. Our data suggest the involvement of calpain in the early stage (especially within 10 min) of microparticle formation.

Antigens, Human Platelet↗
PubMed1993

Calyculin A inhibits the exposure of fibrinogen receptor in thrombin-stimulated platelets.

Calyculin A (CLA) and okadaic acid (OA), specific and potent inhibitors of protein phosphatase 1/2A, inhibit platelet aggregation. However, their inhibitory mechanisms remain unknown. We investigated the effects of CLA on the exposure of fibrinogen receptor in thrombin-stimulated platelets, using flow cytometry with a monoclonal antibody against the fibrinogen receptor of activated glycoprotein(Gp)IIb/IIIa complex (PAC-1). CLA inhibited the exposure of fibrinogen receptor in a dose related manner when added either before or 3 min after thrombin stimulation. In contrast, CLA had no significant effect when the expression of GpIIb/IIIa complex was examined in resting platelets, using a monoclonal antibody recognizing non-activated GpIIb/IIIa complex (NNKY1-32). These results suggest that protein phosphatase 1/2A may be directly involved in the exposure of platelet fibrinogen receptor.

Adult↗
PubMed1993

Primary sites of actions of staurosporine and H-7 in the cascade of insulin action to glucose transport in rat adipocytes.

The insulin-stimulated glucose transporter in rat adipocytes was inhibited by two protein kinase inhibitors, staurosporine (SSP) and H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine). However, whereas SSP (10 microM) blocked the insulin-dependent translocation of glucose transporter, H-7 (3 mM) did not. The latter inhibited glucose transporter activity not only in cells, but also in reconstituted liposomes. On the other hand, SSP blocked both the action of insulin and the insulinomimetic action of GTP gamma S (Guanosine 5'-O-(3-thiotriphosphate)). GTP gamma S had distinct effects on the glucose transport and cAMP phosphodiesterase (PDE) activities. It is suggest that H-7 may inhibit glucose transport activity per se; a SSP sensitive protein kinases (protein kinase C isoforms?) may be involved in cascade of the insulin action on glucose transporter as modulated by GTP gamma S; and glucose transport and PDE activities may be regulated by distinct GTP gamma S-sensitive factors.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

The possible involvement of protein phosphatase 1 in thrombin-induced Ca2+ influx of human platelets.

Protein phosphatase 1 is considered to be involved in thrombin-induced platelet activation (Murata et al., Biochem Int 26:327-334, 1992). To clarify the mechanism, we examined the effects of protein phosphatase 1 and 2A inhibitors (calyculin A, tautomycin, okadaic acid) on Ca2+ influx. In the presence of 1 mM Ca2+, thrombin- (0.1 U/ml) induced platelet aggregation and ATP release were inhibited by calyculin A, while this inhibitory effect was abolished in the absence of Ca2+ (EGTA 1 mM). Furthermore, thrombin-induced Mn2+ influx but not intracellular Ca2+ mobilization was inhibited by calyculin A in a dose-related manner. Calyculin A also blocked the ongoing Ca2+ influx when added 3 min after thrombin stimulation. Similar inhibitory effects were observed with okadaic acid and tautomycin in the same potency sequence as the reported one for protein phosphatase 1 (calyculin A > tautomycin > okadaic acid). These results suggest that the anti-platelet effects of phosphatase inhibitors are due to the inhibition of Ca2+ influx and that protein phosphatase 1 plays a key role in the regulation of receptor operated Ca2+ channel of human platelets.

Antifungal Agents↗
PubMed1993

Ultrastructure of spotted fever rickettsialike microorganisms observed in tissues of Dermacentor taiwanensis (Acari: Ixodidae).

Tissues of midguts, Malpighian tubules, salivary glands, and ovaries of female Dermacentor taiwanensis Sugimoto collected in an area endemic for Japanese spotted fever were examined with an electron microscope, and the presence of two kinds of rickettsialike microorganisms was confirmed in Japan. Based on ultrastructural findings, a rod-shaped organism detected in all the tissues is a Rickettsia; another, irregularly shaped organism that was found only in the ovary, is a Wolbachia. A hemolymph test using a specific immunostain indicated that the Rickettsia belongs to the spotted fever group of rickettsiae.

Animals↗
PubMed1993

Preliminary observations on ultrastructure of borreliae in tissues of Ixodes persulcatus.

We observed Lyme borrelia by electron microscopy in the tissues of the ticks, Ixodes persulcatus, which were indicated positive for borreliae by BSK cultures of their internal organs. Borreliae (0.25 micron in diameter) were found only in the lumen of the midgut. They were closely associated with the microvilli on the midgut epithelium but never penetrated into the epithelial cells. Ultrastructural features common to Lyme borreliae., i.e., the three-layered membranes surrounding the cytoplasm and orientation of the flagella insertions, were obviously confirmed. The present results are useful to understand tick tissue-borrelia interface.

Animals↗
PubMed1993

Identity of pathogenic strains of spotted fever rickettsiae isolated in Shikoku District based on reactivities to monoclonal antibodies.

Three IgG (B2, C3 and F8) and two IgM (S3 and X1) monoclonal antibodies (Mab) were produced in BALB/c mice immunized with Aoki strain of spotted fever (SF) rickettsiae in Tokushima Prefecture, Japan. Of these, two (B2 and C3) reacted equally with six Japanese strains including YH strain, the prototype of R. japonica, but did not react with the foreign strains. These results indicate that SF rickettsial strains from Tokushima Prefecture were identified as R. japonica, and that the SF strains isolated at least in Shikoku District most likely belong to a common serotype.

Aged↗
PubMed1993

Serosurveys of spotted fever and murine typhus in local residents of Taiwan and Thailand compared with Japan.

To estimate the prevalence of spotted fever (SF) and murine typhus (MT) rickettsioses in Southeast Asia, we performed serosurvey by immunoperoxidase test on local residents in Taiwan and Thailand, comparing them with those of Japan. In Japan, the prevalence of antibodies (1:80 as cut-off level) to some SF/MT antigens was noticeable in Japanese SF-endemic areas or a high-risk groups. In Tainan, Taiwan, SF antibodies were not so prevalent (3.5 to 4.4%), but MT antibodies were more prevalent (23.9%). In Chiang Rai in northern Thailand SF antibodies were markedly prevalent (9.0 to 21.3%); the reactivity with Thai tick 118 strain alone was 8.2%, but MT was less (2.5%). These results suggest that these rickettsioses may be latently distributed in various parts of Asia.

Adult↗
PubMed1993

[External work of canine latissimus dorsi muscle after vascular delay].

The first purpose of this study was to estimate physiological performance of skeletal muscle for circulatory assist. External work in the form of linear dynamic contraction was studied in canine latissimus dorsi muscle (LDM). The second purpose was to relate the effect of vascular delay of the LDM to the physiological performance. The left LDM with vascular delay (VD) were compared to the right control LDM (CTR) without vascular delay. Simultaneous dynamic contraction of both VD and CTR LDM were studied under various settings of the preloads and the afterloads. Maximal external work per single contraction were 136 +/- 38 mJ in VD and 81 +/- 21 mJ in CTR. Maximal total work, which includes external work and preload work, were 578 +/- 195 mJ in VD and 407 +/- 146 mJ in CTR. Maximal fractional shortenings of the LDMs were 22.8 +/- 4.7% in VD and 17.5 +/- 2.6% in CTR. The maximal external work of VD was 81% of canine LV stroke work and 620% of canine RV stroke work. The maximal total work of VD was 340% of canine LV stroke work. The fractional shortenings, external work and total work of VD were higher than those of CTR under all loading conditions. The physiologic performance of canine LDM was improved after vascular delay.

Animals↗
PubMed1993

[Severely mentally and physically disabled in Gunma Prefecture].

We studied severity, causes of the disabilities, complications due to disabilities, and past histories of the severely mentally and physically disabled whose guardians or parents were residents in Gunma prefecture on September 1, 1991. This survey was made on severely disabled schoolboys and girls aged 6 to 15 years with IQ of 35 or less who could not stand or walk, even if they were supported. The number of them was 133 at the moment of this survey. Asphyxia at birth and congenital but unknown etiology were the major causes in the institutionalized cases, but cerebral palsy of unknown etiology and "no information" were frequent in the cases cared at home. The institutionalized patients showed severer mental retardations, palsies and disabilities on activities of daily lives, though not with statistically significant difference, and contained significantly larger number of cases fed by gastric tube or having meals as blended foods and significantly smaller number of cases having conventional meals than cases cared at home. Furthermore, epilepsies or constipations as complications were found more frequently in institutionalized cases than in cases cared at home with significant difference. On past history, relatively large numbers of the disabled suffered from various infectious diseases, especially from measles, varicella, mumps and pneumonia. Histories of measles, varicella and mumps showed higher frequency in institutionalized cases than in cases cared at home, though not with significant difference. On the cases cared at home, some of them did not have their home doctors, though in small numbers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Porphyrias].

Explore the source record for details and available documents.

Adolescent↗
PubMed1993

[Prevalence rate of the severely mentally and physically disabled children in Gunma Prefecture].

Children were studied on distribution of the severely mentally and physically disabled aged 6 to 15 years in Gunma Prefecture as of September 1, 1991. They were all bedridden or able to sit, but could not stand or walk, even with support. Today, all the Japanese should attend elementary school as well as junior high school. Even though they are severely disabled, they are all registered by the regional Board of Education, where we could get exact data on the disabled children throughout Gunma Prefecture. We collaborated with the regional Board of Education, the Child Consultation Center of Gunma Prefecture and 6 hospitals for the disabled. A total of 129 cases were found. The population of schoolboys and schoolgirls aged 6 to 15 years of age was 236,000, most of whose guardians were residents of this prefecture, and the prevalence rate was 0.55/1000. Among 129 cases, 53 cases (41.1%) were institutionalized and 76 cases (58.9%) were cared for at home. Fifty-nine cases (45.7%) were males and 70 cases (54.3%) were females. Thirty-four cases were aged 6 to 7 years (26.4%) and older cases declined probably due to premature deaths. Ninety-four of the 129 cases (72.9%) were bedridden and mentally retarded with IQs 20 or less.

Adolescent↗
PubMed1992

Intracellular signal transduction for interleukin-1 beta-induced endothelin production in human umbilical vein endothelial cells.

The authors investigated the intracellular signal transduction for interleukin (IL)-1 beta-induced endothelin (ET) production by endothelial cells from cultured human umbilical vein (HUVEC). Cultured HUVEC released immunoreactive (iR)-ET into the media in a time-dependent manner and a significant increase of iR-ET production was observed by the addition of IL-1 beta. The stimulating effect of IL-1 beta on iR-ET production was respectively inhibited by protein kinase C (C kinase) inhibitor (H-7), Ca-calmodulin inhibitor (W-7), cyclic AMP-dependent protein kinase (A kinase) inhibitor (H-8) and tyrosine kinase inhibitor (genistain) in a dose-dependent fashion. The data suggested that intracellular signal transduction for IL-1 beta-induced iR-ET production were via such pathways as C kinase, A kinase, Ca-calmodulin and tyrosine kinase in combination or independently, though possible mediation by other pathways cannot be ruled out.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Bedside monitoring of warfarin therapy by a whole blood capillary coagulation monitor.

A recently developed portable capillary coagulation monitor device allows rapid determination of prothrombin time (PT) in sec. and in International Normalized Ratio (INR) from a drop of whole blood. Considering a possible application of this device for monitoring of warfarin therapy at bedside or at outpatient clinic, a comparative study was performed in patients receiving warfarin between the whole blood capillary PT(WBC-PT) and conventional laboratory tests such as plasma PT (LAB-PT) and Thrombotest (TTO). There was an excellent positive correlation (r = 0.95, n = 49) between LAB-PT(sec) and WBC-PT(sec). As the correlation coefficient between WBC-PT(sec) and the reciprocal of LAB-PT(%) was excellent (r = 0.95, n = 49), it is feasible to convert WBC-PT(sec) to LAB-PT(%) by the following formula; y = 313.48x +8.29 (x:reciprocal value of LAB-PT(%), y:WBC-PT). As the correlation between WBC-PT(sec) and TTO(sec) was also excellent (r = 0.85, n = 63), TTO(%) may be likewise estimated by the following formula; y = 66.49x + 11.36 (x:reciprocal value of TTO(%), y:WBC-PT). From these observations it is concluded that the determination of WBC-PT is simple and accurate and that the monitoring of warfarin therapy is easily performed by the present method.

Ambulatory Surgical Procedures↗