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G Watanabe

Publications and source records attributed to G Watanabe.

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

Genotype frequency of plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism in healthy Japanese males and its relation to PAI-1 levels.

Plasminogen activator inhibitor-1 (PAI-1) plays an inhibitory role in the fibrinolytic enzyme system and is associated with thrombotic diseases. The gene for PAI-1 has an insertion/deletion polymorphism at the promoter region, the 4G/5G polymorphism, which is related to differences in transcription activity in vitro. Association of the 4G/5G polymorphism with plasma PAI-1 levels, however, has not been uniformly reported. We evaluated the relationship between the 4G/5G polymorphism and plasma PAI-1 antigen levels in 104 Japanese males not taking lipid-lowering drugs and without non-insulin-dependent (type 2) diabetes mellitus or coronary artery disease. The genotype frequency was 37.5%, 50.0%, and 12.5% for 4G/4G, 4G/5G, and 5G/5G genotypes, respectively, which differs from that reported for healthy Caucasian males (P < 0.01), with the 4G allele more frequently found in the Japanese population. No association was found between the 4G/5G polymorphism and plasma PAI-1 antigen levels. Multiple regression analysis revealed a significant (P < 0.01) contribution of triglyceride (TG) levels to variations in plasma PAI-1 antigen levels. The correlation between TG levels and plasma PAI-1 antigen levels was not 4G/5G genotype-specific. These findings suggest that PAI-1 4G/5G polymorphism is not associated with plasma PAI-1 antigen levels among healthy Japanese males and that TG levels correlate to plasma PAI-1 antigen levels in all PAI-1 4G/5G genotypes.

Adult↗
PubMed1999

Cologastric fistula and colonic perforation as a complication of percutaneous endoscopic gastrostomy.

Cologastric fistula has rarely been reported as a complication of percutaneous endoscopic gastrostomy (PEG). We encountered a patient in whom this problem went unrecognized for 2 years. After the initial PEG tube was changed, the second PEG tube was advanced into the colon, causing severe diarrhea. When a third PEG tube was inserted, acute peritonitis occurred because of colonic perforation. We discuss the mechanism of this complication and technical points related to its prevention.

Aged↗
PubMed1998

Targeted downregulation of caveolin-1 is sufficient to drive cell transformation and hyperactivate the p42/44 MAP kinase cascade.

Caveolin-1 is a principal component of caveolae membranes in vivo. Caveolin-1 mRNA and protein expression are lost or reduced during cell transformation by activated oncogenes. Interestingly, the human caveolin-1 gene is localized to a suspected tumor suppressor locus (7q31.1). However, it remains unknown whether downregulation of caveolin-1 is sufficient to mediate cell transformation or tumorigenicity. Here, we employ an antisense approach to derive stable NIH 3T3 cell lines that express dramatically reduced levels of caveolin-1 but contain normal amounts of caveolin-2. NIH 3T3 cells harboring antisense caveolin-1 exhibit anchorage-independent growth, form tumors in immunodeficient mice and show hyperactivation of the p42/44 MAP kinase cascade. Importantly, transformation induced by caveolin-1 downregulation is reversed when caveolin-1 protein levels are restored to normal by loss of the caveolin-1 antisense vector. In addition, we show that in normal NIH 3T3 cells, caveolin-1 expression levels are tightly regulated by specific growth factor stimuli and cell density. Our results suggest that upregulation of caveolin-1 may be important in mediating contact inhibition and negatively regulating the activation state of the p42/44 MAP kinase cascade.

3T3 Cells↗
PubMed1998

Effects of an antisense oligodeoxynucleotide for neuropeptide Y mRNA on in vivo luteinizing hormone-releasing hormone release in ovariectomized female rhesus monkeys.

The present study examines the effects of an antisense oligodeoxynucleotide (AS) for human neuropeptide Y (NPY) mRNA on in vivo LHRH release using the push-pull perfusion method in female ovariectomized monkeys. After 6 h of control perfusion, 10 microM of the AS NPY was infused for 8 h, which was followed by an additional 4 h of control perfusion. As a control for AS, an oligodeoxynucleotide containing the same bases in a scrambled sequence (SC) was similarly examined. LHRH and NPY levels in perfusate samples, collected in 10-min fractions, were measured by RIA. AS NPY infusion resulted in a significant decrease in mean NPY release starting 2 h after the initiation of infusion, and continuing until shortly after the end of AS infusion (P < 0.05, n = 7). AS NPY also suppressed mean LHRH release significantly (P < 0.05, n = 7): the AS NPY-induced LHRH suppression started 2 h after the initiation of AS infusion, and continued throughout AS infusion, lasting for the entire period of the experiment. In contrast, SC NPY resulted in neither significant changes in NPY release nor LHRH release. These data suggest that NPY release in the stalk-median eminence plays an important role in the control of pulsatile release of LHRH in vivo in the rhesus monkey.

Animals↗
PubMed1998

Different regions of Rho determine Rho-selective binding of different classes of Rho target molecules.

Based on their Rho binding motifs several Rho target molecules can be classified into three groups; class I includes the protein kinase PKN, rhophilin, and rhotekin, class II includes the protein kinases, Rho-associated coiled-coil containing protein kinases, ROCK-I and ROCK-II, and class III includes citron. Taking advantage of the selectivity in recognition by these targets between Rho and Rac, we examined the regions in Rho required for selective binding of each class of Rho target molecules. Yeast two-hybrid assays were performed using Rho/Rac chimeras and either rhophilin, ROCK-I, or citron. This study showed the existence of at least two distinct regions in Rho (amino acids 23-40 and 75-92) that are critical for the selective binding of these targets. The former was required for binding to citron, whereas the latter was necessary for binding to rhophilin. On the other hand, either region showed affinity to ROCK-I. This was further confirmed by ligand overlay assay using both recombinant ROCK-I and ROCK-II proteins. Consistently, Rho/Rac chimeras containing either region can induce stress fibers in transfected HeLa cells, and this induction is suppressed by treatment with Y-27632, a specific inhibitor of ROCK kinases. These results suggest that the selective binding of different classes of Rho targets to Rho is determined by interaction between distinct Rho-binding motifs of the targets and different regions of Rho.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Regulation of cyclin dependent kinase inhibitor proteins during neonatal cerebella development.

The cyclin dependent kinase holoenzymes (CDKs), composed of catalytic (cdk) and regulatory (cyclin) subunits, promote cellular proliferation and are inhibited by cyclin dependent kinase inhibitor proteins (CDKIs). The CDKIs include the Ink4 family (p15Ink4b, p16Ink4a, p18Ink4c, p19Ink4d) and the KIP family (p21Cip1 and p27Kip1). The sustained induction of p21 and p18 during myogenesis implicates these CDKI in maintaining cellular differentiation. Herein we examined the CDK (cyclin D1, cdk5) and CDKI expression profiles during the first 24 days of postnatal rat cerebella development. Cdk5 abundance increased and cyclin D1 decreased from day 9 through to adulthood. The CDKIs increased transiently during differentiation. p27 increased 20-fold between days 4 and 24, whereas p21 rose twofold between 6 to 11 days. p19, p18 and p16 increased approximately two- to threefold, falling to low levels in the adult. Immunostaining of cyclin D1 was localized in the external granular cells, whereas p27, was found primarily in the Purkinje cells. The period of maximal differentiation between days 9 to 13 was associated with a change in p21 and p16 staining from the external granular and Purkinje cells to a primarily Purkinje cell distribution. Protein-calorie malnutrition, which was previously shown to arrest rat cerebella development, reduced cyclin D1 kinase activity and p27 levels. However, p16 and p21 levels were unchanged. We conclude that the CDKIs are induced with distinct kinetics in specific cell types and respond differentially to growth factors during cerebella development, suggesting discrete roles for these proteins in normal cerebella development.

Animals↗
PubMed1998

Inhibitory regulation of inhibin gene expression by thyroid hormone during ovarian development in immature rats.

To explore the role of the thyroid gland in ovarian development during the initiation process of puberty, we examined the effects of hypothyroidism on the secretion of ovarian hormones during equine chorionic gonadotropin (eCG)-induced follicle development in immature female rats. Immature rats at 22 days of age were thyroidectomized (Tx) to cause hypothyroidism and then given a single s.c. injection of 5 IU eCG at 26 days of age to induce normal first ovulation. The blood samples were collected at 0, 24, and 48 h after eCG treatment to measure inhibin and estradiol by radioimmunoassay. Serum inhibin and estradiol levels in eCG-primed Tx animals were significantly higher at 24 and 48 h after eCG treatment than those in controls (eCG treated non-Tx rats). The number of healthy follicles larger than 400 microns in diameter and ovarian weight were significantly increased in Tx rats at 48 h after eCG treatment, compared to those in controls. The number of oocytes which are ovulated by an injection of human chorionic gonadotropin (10 IU) was significantly increased on the day after eCG treatment, compared to that of eCG treated non-Tx rats. The increments in both hormones levels, the number of large antral follicles, and ovarian weight in eCG-primed Tx animals were suppressed up to control levels with daily administrations of 5.0 micrograms thyroxine (T4) for 6 days during 22 to 27 days of age. The expression of mRNAs for inhibin alpha and beta A subunits increased in eCG-primed Tx rats at 48 hr after eCG treatment, and the increase in inhibin mRNAs was suppressed by T4 treatment up to control levels. These results clearly demonstrate that thyroid hormone takes part in an inhibitory regulation of ovarian hormonal secretion and folliculogenesis in eCG-primed immature female rats.

Animals↗
PubMed1998

Simultaneous genotyping of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) loci by amplified product length polymorphism (APLP) analysis.

Genotyping of the alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) loci is important in alcohol studies. We describe a method for simultaneous genotyping of ADH2 and ALDH2 based on amplified product length polymorphism (APLP) analysis. Two polymerase chain reaction (PCR) fragments for ADH2 (57 bp, 53 bp) and two for ALDH2 (78 bp, 73 bp) are simultaneously amplified. Nine banding patterns reflecting the genotypes of the ADH2 and ALDH2 loci are clearly and unambiguously distinguished. The APLP method seems to be particularly suited for large-scale population studies of ADH2 and ALDH2 loci because it is simple and rapid.

Alcohol Dehydrogenase↗
PubMed1998

Surgical Procedure for Right Anteroseptal Accessory Conduction Pathways in Wolff-Parkinson-White Syndrome.

In patients with Wolff-Parkinson-White syndrome, the right anteroseptal accessory conduction pathway is rare, and exists from the atrium to the ventricle in close anatomic proximity to the normal atrioventricular conduction system. Catheter ablation of this lesion is reported to interrupt atrioventricular node-His bundle conduction more easily than that of other lesions. At our institute, there were 10 patients with right anteroseptal accessory conduction pathway among 454 patients (2.2%) who underwent the surgical division of the accessory pathway. Our procedure involved the the endocardial approach with knife dissection and cryocoagulation. With the heart beating under normothermal cardiopulmonary bypass, delta wave disappearance was easily noted. Neither complete atrioventricular block nor recurrent conduction occurred. Cryoablation used by our endocardial surgical division, is a safe and accurate procedure.

Journal Article↗
PubMed1998

Pathological Analysis of the Radial and Internal Thoracic Artery.

To evaluate the usefulness of the radial artery (RA) as a graft material for coronary artery bypass grafting (CABG), histologic studies of the RA were performed and compared with the internal thoracic artery (ITA). Specimens were obtained from both ends of 12 RAs and the distal side of the ITA during the operation. The degree of arteriosclerosis was evaluated using an NIH Image 1.57 system. The pathological index of arterioslerotic change was expressed as the ratio of cross-section (Rx: internal luminal area/tunica media area). The mean arteriosclerotic ratio (Rx) of the 12 proximal sides of the RA specimens was 0.18 +/- 0.03, the 12 distal sides 0.27 +/- 0.17, and the 12 ITAs was 0.14 +/- 0.05, respectively. There was significant difference between the distal side of the RA and the ITA. The distal side of the RA was a little greater than the proximal, but there was no significant difference between the proximal side of the RA and the ITA. From the microscopic findings, the tunica media of the RA is poor in elastic fibers and rich in smooth muscle cells compared with the ITA. The internal elastic lumina of the RA is developed as well as the ITA, but more calcification was found in the distal RA than in the others. According to these results, although care must be taken for arteriosclerosis of the distal RA, it can be expected to be a suitable bypass material for CABG.

Journal Article↗
PubMed1998

Bilateral thoracoscopic minimally invasive direct coronary artery bypass grafting using internal thoracic arteries.

BACKGROUND: Single-vessel coronary artery bypass grafting of the left internal mammary artery (ITA) to the left anterior descending coronary artery using a minithoracotomy has been shown to produce excellent results with a very low mortality. However, this procedure cannot be used in patients with double- or triple-vessel disease. Our goal was to develop a minimally invasive direct coronary artery bypass grafting procedure without cardiopulmonary bypass for patients with multivessel disease. METHODS: Both ITAs were thoracoscopically harvested using video imaging. Limited bilateral anterior thoracotomies were performed in the fourth intercostal spaces, thus exposing the right coronary artery and the left anterior descending coronary artery. The right ITA-right coronary artery and ITA-left anterior descending coronary artery anastomoses were performed without cardiopulmonary bypass using 8-0 polypropylene sutures. RESULTS: This procedure was successfully performed in 3 patients. The patients were extubated in the operating room. Postoperative angiographic studies showed patent left ITA and right ITA grafts. CONCLUSIONS: Bilateral thoracoscopic minimally invasive direct coronary artery bypass grafting can be used to treat patients with a proximally diseased left anterior descending coronary artery and right coronary artery. Bilateral thoracoscopic ITA harvesting is a less invasive surgical technique that may become an option for the management of multivessel coronary artery disease.

Aged↗
PubMed1998

Effect of passive immunization against inhibin on FSH secretion, folliculogenesis and ovulation rate during the follicular phase of the estrous cycle in mares.

Physiological roles of inhibin in mares were investigated by means of passive immunization using an antiserum to inhibin that had been raised in a castrated goat. Eight mares were given an intravenous injection of either 100 mL (n = 4) or 200 mL (n = 4) of inhibin antiserum 4 d after a single intramuscular injection of PGF2 alpha on Day 8 after ovulation, 4 control mares were treated with 100 mL castrated goat serum in the same manner. Jugular vein blood samples were collected after treatment with the serum until 192 h post treatment. Follicular growth and ovulations were monitored by ultrasound examination at 24-h intervals. The ability of the inhibin antiserum to neutralize the bioactivity of equine inhibin was examined in vitro using a rat pituitary cell culture system. Suppression of secretion of FSH from cultured rat pituitary cells by equine follicular fluid was reversed by the addition of increasing doses of the inhibin antiserum, thereby indicating its bioactivity. Plasma levels of FSH and estradiol-17 beta were higher in mares treated with the inhibin antiserum. The ovulation rate was significantly higher in mares treated with antiserum (100 mL = 3.75 +/- 0.63; 200 mL = 4.50 +/- 0.65) than in control mares (1.25 +/- 0.25). These results demonstrate that inhibin is important in regulating FSH secretion and folliculogenesis in mares. They also show that neutralization of the bioactivity of inhibin may become a new method for the control of folliculogenesis and ovulation rate in mares.

Animals↗
PubMed1998

Overexpression of the rhoC gene correlates with progression of ductal adenocarcinoma of the pancreas.

It has been reported that the rho genes, which consist of a ras-related small GTPase protein family, regulate cytoskeletal structures and have the potential to transform cultured cells. To investigate the biological relevance of the rho genes in pancreatic carcinogenesis, we examined expressions of the rhoA, B and C genes by polymerase chain reaction after reverse transcription (RT-PCR) in 33 cases of ductal adenocarcinoma of the pancreas. In addition, mutations of the K-ras, rhoA, B and C genes were studied in the same series of tumour tissues to correlate with rho gene expressions. The expression levels of the rhoC gene were significantly higher in tumours than in non-malignant portions (P < 0.001). Metastatic lesions overexpressed the rhoC gene compared with primary tumours (P < 0.05). Carcinoma tissues with perineural invasion and lymph node metastasis exhibited significantly higher expressions of the rhoC gene than tumours without these manifestations (P < 0.001 and P < 0.05 respectively). Overexpression of the rhoC gene significantly correlated with poorer prognosis of patients with pancreatic adenocarcinoma (P < 0.05). In contrast, the expression levels of the rhoA and B genes showed no significant relationship with clinicopathological findings. Mutation was not found either in the rhoA, B or C gene sequences examined. K-ras gene mutation, detected in 27 out of 33 (81.8%) cases, did not affect the expression levels in any of the rho genes. These suggest that elevated expression of the rhoC gene may be involved in the progression of pancreatic carcinoma independent of K-ras gene activation.

Adult↗
PubMed1998

In oesophageal squamous cell carcinoma vascular endothelial growth factor is associated with p53 mutation, advanced stage and poor prognosis.

Vascular endothelial growth factor (VEGF) affects malignant tumours by promoting angiogenesis. The tumour-suppressor gene p53 has been thought to regulate VEGF. We investigated the effect of VEGF on oesophageal carcinoma and the connection between VEGF and p53. One hundred and nine resected oesophageal squamous cell carcinomas were examined. VEGF expression was analysed by immunohistochemical staining. Sixty-five tumours (59.6%, 65 out of 109) were classified as VEGF positive. A significant correlation was found between the VEGF expression and both the depth of invasion (P = 0.0001) and lymph node metastasis (P < 0.0001). With regard to p53, we compared the expression of VEGF with the mutation of p53, examined using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing in tumour samples obtained from 36 patients who we have reported previously. The VEGF expression was significantly correlated to p53 mutation (P = 0.0291). To evaluate the angiogenesis, microvascular density (MVD) was counted, and endothelial cells were stained immunohistochemically using anti-CD34 monoclonal antibody against 29 cases with invasion limited to the submucosal layer. The average MVD had a tendency to correlate to VEGF expression (P = 0.1626). The prognoses of patients with VEGF-positive primary tumours were significantly worse than for those with VEGF-negative primary tumours (P = 0.0077). We have assumed that VEGF contributes to aggressive characteristics in oesophageal carcinomas and that VEGF expression might be affected by p53 status.

Carcinoma, Squamous Cell↗
PubMed1998

Testicular inhibin in the stallion: cellular source and seasonal changes in its secretion.

The cellular localization of inhibin alpha, betaA, and betaB subunits, 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and cytochrome P450 aromatase (aromatase) in stallion testes was investigated. In addition, detailed seasonal changes in circulating immunoreactive (ir)-inhibin were investigated in correlation with testosterone, estradiol, LH, and FSH. Inhibin alpha subunit-positive staining was observed in Sertoli cells, and more clearly positive staining was noted in Leydig cells. Inhibin betaA and betaB subunits were also stained in both types of cells. Immunoreactivity of 3beta-HSD and aromatase was confined to the Leydig cells. There was no seasonal effect on the percentage of the areas within seminiferous tubules and interstitial tissues that stained positive for the inhibin alpha subunit. The highest plasma concentrations of ir-inhibin were observed in the breeding season, and the lowest levels were noted during the nonbreeding season. The circulating concentrations of ir-inhibin, steroid hormones, and gonadotropins were positively correlated with each other throughout the 2 years studied. The presence of the inhibin alpha and beta subunits in Leydig cells and Sertoli cells in the equine testis suggests that these cells may secrete dimetric (bioactive) inhibin in circulation of stallions, and that the circulating ir-inhibin may be a useful indicator of the testicular function of stallions.

3-Hydroxysteroid Dehydrogenases↗
PubMed1998

Inhibin secretion in the mare: localization of inhibin alpha, betaA, and betaB subunits in the ovary.

To determine the source of circulating inhibin and estradiol-17beta during the estrous cycle in mares, the cellular localization of the inhibin alpha, betaA, and betaB subunits and aromatase in the ovary was determined by immunohistochemistry. Concentrations of immunoreactive (ir-) inhibin, estradiol-17beta, progesterone, LH, and FSH in peripheral blood were also measured during the estrous cycle in mares. Immunohistochemically, inhibin alpha subunits were localized in the granulosa cells of small and large follicles and in the theca interna cells of large follicles, whereas inhibin betaA and betaB subunits were localized in the granulosa cells and in the theca interna cells of large follicles. On the other hand, aromatase was restricted to only the granulosa cells of large follicles. Plasma ir-inhibin concentrations began to increase 9 days before ovulation; they remained high until 2 days before ovulation, after which they decreased when the LH surge was initiated. Thereafter, a further sharp rise in circulating ir-inhibin concentrations occurred during the process of ovulation, followed by a second abrupt decline. After the decline, plasma concentrations of ir-inhibin remained low during the luteal phase. Plasma estradiol-17beta concentrations followed a profile similar to that of ir-inhibin, except during ovulation, and these two hormones were positively correlated throughout the estrous cycle. Plasma FSH concentrations were inversely related to ir-inhibin and estradiol-17beta. These findings suggest that the dimeric inhibin is mainly secreted by the granulosa cells and the theca cells of large follicles; granulosa cells of small follicles may secrete inhibin alpha subunit, and estradiol-17beta is secreted by the granulosa cells of only large follicles in mares.

Animals↗