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Biomedical subjects

K Shigeta

Publications and source records attributed to K Shigeta.

At least 19 recordsLinked to original sources
PubMed2002

Simultaneous voiding cystourethrography and voiding urosonography: an in vitro and in vivo study.

AIM: To compare the diagnostic accuracy of fluoroscopic voiding cystourethrography (VCUG) and voiding urosonography (VUS) under identical conditions. We performed VUS and VCUG simultaneously with the total time for both examinations taking no longer than the time required for either examination individually. MATERIALS AND METHODS: X-ray contrast medium and echo-contrast agent were mixed together in vitro, and echogenicity of the mixture was confirmed. A clinical study was then performed on 33 children who had a history of urinary tract infection. The bladder was filled using simultaneous administration of X-ray contrast medium and echo-contrast agent. VCUG and VUS were then performed simultaneously and evaluated separately by two specialists. RESULTS: Equivalent results were obtained for the two examinations in 61 of 66 renal tracts. Sensitivities of VUS and VCUG for the detection of VUR were 86% and 79%, respectively. The average time from catheterization to the completion of the study was 9.1 minutes - approximately as long as performing VCUG alone. CONCLUSIONS: First, the present simultaneous study is superior to previous comparisons, because the two examinations were performed under identical physiologic conditions. Second, our results suggest that the two techniques demonstrate similar sensitivity in the detection of reflux.

Child↗
PubMed2001

Enhancement of developmental competence after in vitro fertilization of porcine oocytes by treatment with ascorbic acid 2-O-alpha-glucoside during in vitro maturation.

The present study was conducted to examine the effect of ascorbic acid 2-O-alpha-glucoside (AA-2G), a stable ascorbate derivative, on the sustenance of cytoplasmic maturation responsible for subsequent developmental competence after in vitro fertilization of porcine oocytes. Cumulus-oocyte complexes were cultured for 44 h in North Carolina State University 37 medium supplemented with cysteine, gonadotropins, 10% (v:v) porcine follicular fluid, and 0-750 microM AA-2G. When oocytes were matured in the presence of 250 microM AA-2G, their ability to promote transformation of the sperm nucleus into the male pronucleus (MPN) was strongly enhanced after in vitro fertilization. Similarly, the presence of 25 microM beta-mercaptoethanol (ME) enhanced the degree of progression to MPN of penetrated sperm by associating with the increase in intracellular glutathione (GSH) content. Although the AA-2G treatment during oocyte maturation showed no influence on the GSH concentration, significantly higher levels of ascorbic acid (AsA) were detected in these oocytes than in those oocytes cultured without AA-2G (P < 0.05). The length of DNA migration encompassed by reactive oxygen species (ROS), generated by the hypoxanthine-xanthine oxidase system, was not increased in the oocytes treated with AA-2G, whereas ME treatment could not block the DNA damage by ROS. These findings indicate that AA-2G in maturation medium can potentiate the cellular protection of oocytes against oxidative stress by continuously supplying AsA. The proportion of development to the blastocyst stage after in vitro insemination was significantly increased in oocytes matured with AA-2G (P < 0.05), and this proportion showed no difference in comparison with that of oocytes treated with ME. These findings suggest that a critical concentration of intracellular AsA, supplied by AA-2G during in vitro maturation, plays an important role in supporting the cytoplasmic maturation responsible for developmental competence after fertilization by prevention of oxidative stress against porcine oocytes.

Animals↗
PubMed2001

[Simultaneous surgery for unstable angina and gastric cancer: a case report].

This report describes a case in which an 81-year-old male underwent two operations simultaneously for unstable angina and gastric cancer. Successfully performed procedures were off pump CABG with bilateral IMA, and total gastrectomy. The post operative course was uneventful. Off pump CABG is an effective procedure in patient with malignant neoplasm.

Adenocarcinoma↗
PubMed2001

[Responses to a questionnaire on laboratory examinations performed by graduates of Jichi Medical School in rural practice].

Graduates from Jichi Medical School are obligated to work at rural clinics or hospitals, where most of them are the only medical doctor in the house. Our need to continuously improve medical education, including the learning that takes place in the clinical setting, requires us to understand how these graduates actually use laboratory examinations and what examinations they find most important in their practice. We designed a questionnaire to address these questions. Three hundred sixty-eight graduate physicians working at clinics or hospitals in both rural or urban areas were asked to complete the questionnaire, providing information on the size of their institution, the laboratory equipment and examinations that they have direct access to, and what examinations they find most important. Two hundred seventy-eight (75.5%) of the 368 recipients responded. More than seventy percent of the respondents reported that their institutions had electrocardiographs, abdominal and cardiac ultrasonographs, urinalysis test paper, and portable blood glucose meters; and more than half of them reported having used these instruments without assistance in emergency situations and outside of ordinary office hours. Moreover, a majority of the respondents said that they considered it important that a physician is able to use these instruments without the help of other staff members. These responses clearly show the importance and usefulness of covering examination techniques and the principles of laboratory medicine in medical education.

Attitude of Health Personnel↗
PubMed2000

Cubic-Phase-Based Concentrated Emulsions.

The effect of different types of added oil on the formation of a discontinuous micellar-type cubic phase was investigated in water-polyoxyethylene dodecyl ether (C(12)EO(25)) systems by phase study and small-angle X-ray scattering. The thermal stability of the cubic phase increases upon addition of oil, especially short-chain hydrocarbons. However, in the heptane system, the maximum melting temperature of the cubic phase is lower than that for decane due to the formation of a different liquid crystal phase. The effect of polyols on C(12)EO(25) cubic phases was also investigated. It was found that the thermal stability of the cubic phase decreases with polyol concentration. The destabilizing effect becomes large as the polyol molecule penetrates further into the surfactant palisade layer. Although the solubilization of oil in the cubic phase is very low, a large amount of excess oil can be incorporated and a transparent cubic-phase-based concentrated emulsion is formed. The transparency is attributed to the very small difference in the refractive indices between the cubic and excess-oil phases. Copyright 2000 Academic Press.

Journal Article↗
PubMed1998

Sck interacts with KDR and Flt-1 via its SH2 domain.

Vascular endothelial growth factor (VEGF) is one of the major angiogenesis regulators. It binds to its tyrosine kinase receptors, KDR and Flt-1. However, little is known about their downstream signal transduction properties. We screened human brain cDNA library using the yeast two-hybrid system with the KDR cytoplasmic region as bait to find KDR binding proteins. After 6.2 x 10(6) clones were screened, we identified Sck, one of the Shc homologues, as a KDR binding protein. Sck also binds to Flt-1 and their binding is dependent on the kinase activities of KDR and Flt-1. Extensive site-directed mutagenesis of KDR revealed that Y1175 of KDR is a major binding site for Sck. As Sck contains the SH2 domain and PTB domain, we tested whether they bind to KDR and Flt-1. The SH2 domain of Sck binds to both of them. Deletion of the SH2 domain from Sck resulted in the complete loss of binding. On the other hand, the PTB domain of Sck does not bind to KDR and Flt-1. These results indicate that Sck binds to KDR and Flt-1 via its SH2 domain and might play an important role in VEGF signal transduction.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Tyrosine 1213 of Flt-1 is a major binding site of Nck and SHP-2.

Vascular endothelial growth factor (VEGF) binds to its receptor tyrosine kinase Flt-1 and KDR/Flk-1 and stimulates their autophosphorylation. However, little is known about their downstream signal transduction properties. We examined the interactions of certain proteins with a SH2-domain with Flt-1 and KDR using the yeast two-hybrid system and found that Nck, SHP-2, PLC gamma, and PI3K p85 bind to Flt-1. Extensive site-directed mutagenesis of Flt-1 revealed their major binding sites. Nck, SHP-2, and PI3K bind to Y1213 of Flt-1. Nck also binds to Y1333 of Flt-1. These results suggest that Nck, SHP-2, PLC gamma, and PI3K play important roles in Flt-1 signal transduction and that Y1213 of Flt-1 is a major binding site of PI3K, Nck, and SHP-2.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Examination of the diagnostic value and estimation of the chaos phenomenon in masticatory movement using fractal dimension in patients with temporomandibular dysfunction syndrome.

The aim of this study was to estimate the chaos phenomenon (chaos) in masticatory movements using the fractal dimension (FD), and to examine the diagnostic value of the fractal dimension in comparing stomatognathic functional disturbances with normal stomatognathic function. The subjects were all high school students and included nine subjects presenting with acceptable normal occlusion, 18 subjects with TMJ dysfunction syndrome and seven subjects with tooth crowding. Masticatory movements were obtained during free, right side, and left side gum-chewing and were used to calculate the capacity dimension in the FD. Chaos in the masticatory movement was estimated by the FD saturated with some constant value to an increase of embedding dimension (approached a plateau). In the crowding group, the FD was also significantly high on the sagittal plane in comparison with the normal. In the patients with pain, the FD on the sagittal plane was significantly high. In the patients with pain and closed lock, the FD on the frontal plane was significantly high. However, in the patients with pain and with reduction of anterior disc displacement, the FD was significantly low on the horizontal plane. These findings suggest that chaos is present in masticatory movements and the difference in the FD are of diagnostic value in evaluation of the relationship between FD and stomatognathic functional disturbance.

Adolescent↗
PubMed1998

8-(3-oxo-4,5,6-trihydroxy-3h-xanthen-9-yl)-1-naphthoic acid inhibits MAPK phosphorylation in endothelial cells induced by VEGF and bFGF.

Angiogenesis is regulated by various factors. In particular, VEGF and basic FGF are of much importance. We found that 8-(3-oxo-4,5,6-trihydroxy-3h-xanthen-9-yl)-1-naphthoic acid inhibited the binding of VEGF to KDR/Flk-1 (VEGF receptor-2) or Flt-1 (VEGF receptor-1) and that it inhibited the MAPK phosphorylation in HUVEC induced by VEGF or basic FGF but not by EGF. 8-(3-oxo-4,5,6-trihydroxy-3h-xanthen-9-yl)-1-naphthoic acid might be used as an inhibitor of VEGF and basic FGF signal transduction.

Journal Article↗
PubMed1998

[A case of advanced gastric cancer with virchow's metastasis responding remarkably to combination chemotherapy of low-dose CDDP and 5-FU].

The patient was a 72-year-old female who had Stage IVb advanced gastric cancer with Virchow's and paraaortic lymph node metastases. She was considered nonresectable and placed on neoadjuvant chemotherapy consisting of low-dose CDDP and 5-FU. After 1 course of administration, Virchow's metastasis disappeared, and the tumor was remarkably reduced in size. However, this chemotherapy was interrupted by toxicity of grade 3 appetite loss, nausea and vomiting, so that total gastrectomy and splenectomy were performed, which were non-curative operation because of paraaortic lymph node metastases. Histopathological examination of the section of the primary tumor revealed that cancer cells had almost disappeared, and only a few atypical cells remained in the granulation tissue. Eleven months after the surgery, there has been no progression of Virchow's and paraaortic lymph node metastases. Combination chemotherapy of low-dose CDDP and 5-FU appears useful as an inductive approach to advanced gastric cancer.

Adenocarcinoma↗
PubMed1997

Thrombin activates NF-kappa B through thrombin receptor and results in proliferation of vascular smooth muscle cells: role of thrombin in atherosclerosis and restenosis.

We investigated the role of thrombin in the pathogenesis in atherosclerosis and restenosis. First we examined the effect of thrombin on cultured human vascular smooth muscle cells (VSMC). We showed that thrombin acts as a mitogen on VSMC through thrombin receptor. The expression of thrombin receptor was increased in the cell lines of VSMC established from directional coronary atherectomy (DCA). This is more pronounced in the cells from patients with restenosis after PTCA. Next we investigated the signaling pathway from thrombin/thrombin receptor. Thrombin activates thrombin receptor resulting in the exposing of the agonist peptide domain (thrombin receptor agonist peptide, TRAP). The signal from thrombin/thrombin receptor activated protein C kinase, tyrosine kinase, and MAP kinase and resulted in NF-kappa B activation. Furthermore, treatment of the cells with antisense p65 oligodeoxynucleotides of NF-kappa B inhibited the thrombin-stimulated growth of VSMC in vitro. These results suggest that thrombin may have a role in the pathogenesis of atherosclerosis and restenosis after PTCA through the thrombin receptor.

Arteriosclerosis↗
PubMed1996

Therapeutic effect of secretin in patients with jaundice; double-blind placebo-controlled multicentric trial.

Secretin, a gastrointestinal hormone, has been shown to have a potent choleretic effect. Having already obtained some beneficial effects with secretin in patients with intrahepatic cholestasis, we sought to confirm its effects in a double-blind placebo-controlled study in patients with mild jaundice after acute or during chronic hepatitis, where total bilirubin level was in excess of 4.0 mg/dl for 3 days or more. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and familiar hyperbilirubinemia were excluded from the study. Ninety-three patients were included in this analysis, but the final evaluation covered 69 of them. No statistically significant differences were found in the reduction of serum bilirubin levels between secretin and placebo groups. As a number of patients with liver cirrhosis had been included, the subjects were subdivided into one group with cholestasis in hepatitis and one with liver cirrhosis. In the subgroup of cirrhotic patients who received secretin, serum levels of AST were significantly increased compared with the placebo group. However, since the choleretic effect of secretin is unique, further studies seem to be warranted.

Adolescent↗
PubMed1996

[Relation of sputum and feces and methicillin-resistant Staphylococcus aureus (MRSA) detection].

Thirty cases with MRSA in the sputum (carrier state) were studied in relation to fecal MRSA detection. The back ground of the cases (disease, nasogastric tube, tracheostomy, antibiotics, H2-blocker) and typing of MRSA (coagulase type, Pulse Field Gel Electrophoresis (PFGE) type), and gastric pH were studied. Almost all of the patients were given antibiotics of the cephem series of the third generation. None of the cases had abdominal operations. Fecal MRSA was positive in 14 cases (47%). H2-receptor antagonists (H2-blocker) was administered to 6 cases, and all cases (100%) had positive fecal MRSA. Eighteen cases had a history of H2-blocker administration and 5 cases had positive fecal MRSA. Duration after stopping the H2-blocker in the 5 cases was shorter than the other 13 cases. (4.5 to 20.8 months). Nasogastric tube had no significant effect in detection of fecal MRSA. And gastric pH was of no significant difference between MRSA positive cases and negative cases. These results suggest that in patient with MRSA in the sputum receiving a H2-blocker may produce MRSA enteritis because of MRSA passage to the stomach.

Adult↗
PubMed1995

Thrombin receptor-mediated synovial proliferation in patients with rheumatoid arthritis.

Synovial cell proliferation is one of the pathological bases of rheumatoid arthritis (RA). Several cytokines including IL-1 and IL-6 and growth factors have been shown to be involved in the synovial cell proliferation in RA. Thrombin is a multifunctional protease and acts as a mitogen for several cell types through its specific receptor. To assess whether thrombin is involved in overproliferation of rheumatoid synovial cells, we measured the concentration of thrombin-anti-thrombin III (ATIII) complex (TAT) in synovial fluid obtained from patients with RA or osteoarthritis (OA). We also examined the effect of thrombin or thrombin receptor agonist peptide (TRAP) on cell growth of synovial cell clones (SCCs) established from an RA patient. The concentrations of TAT in the synovial fluid from patients with RA were significantly higher than in those with OA. Moreover, both thrombin and TRAP enhanced proliferation of synovial cells in vitro. We also characterized the expression of thrombin receptor mRNA by reverse transcription-PCR. The expression of mRNA for thrombin receptor was up-regulated by thrombin or TRAP stimulation. Thrombin receptor antigen was also detected on both SCCs and synovial tissue from RA patients by immunostaining using a monoclonal antibody against thrombin receptor. These findings indicate that thrombin may act as a mitogen for synovial cells through thrombin receptor and may play some role in synovial overproliferation and remodeling in RA.

Adult↗
PubMed1994

Involvement of NF-kappa B activation in thrombin-induced human vascular smooth muscle cell proliferation.

A thrombin receptor has been cloned and is thought to mediate a variety of thrombin-induced responses. However, the transcription factors important for postreceptor signaling have been little clarified. The post-receptor signals are mediated by several protein kinases responsible for NF-kappa B activation, and most thrombin-inducible genes have the kappa B sequence in the regulatory elements. The possibility that NF-kappa B may participate in thrombin signaling was therefore investigated in cultured human vascular smooth muscle cells (VSMCs). Thrombin receptor stimulation resulted in activation of NF-kappa B. Furthermore, treatment of cells with antisense p65 ODNs of NF-kappa B inhibited thrombin-stimulated growth of VSMC in vitro. Results indicate that the activation of NF-kappa B is involved in thrombin signaling and that this pathway causes the proliferation of VSMC induced by thrombin. Therapeutic potential of antisense NF-kappa B ODNs for the treatment with atherosclerosis and restenosis is also indicated.

Acid Phosphatase↗
PubMed1994

[Regulation of the endothelial function by thrombomodulin and/or thrombin receptor].

Thrombin, the final product of blood coagulation cascade, shows several effect on the vessel-wall cells. However the effects may be regulated by several thrombin receptors on the endothelium. They include thrombomodulin (TM), protease-Nexin, heparin-like molecule-antithrombin III complex. These binding sites do not transduce the signal of thrombin. Especially TM converts thrombin from a procoagulant protease to an anticoagulant. Recently new thrombin receptor was identified on the endothelium and platelets. Through this receptor, thrombin induces activations both on platelet end-endothelium. In brief platelets aggregate and release several factors including serotonin, PDGF, platelet factor4, beta-thromboglobulin on the stimulation by thrombin. The endothelium release t-PA inhibitor; PAI-1, prostacyclin and endothelin. Thus the activations of these cells by thrombin is a key events in hemostasis, wound healing, inflammation, atherosclerosis and restenosis of coronary artery after PTCA.

Blood Platelets↗