Biomedical subjects

G Watanabe

Publications and source records attributed to G Watanabe.

At least 217 records · Page 12Linked to original sources

PubMed1997

Cyclin D1 is required for S phase traversal in bovine tracheal myocytes.

We examined the role of cyclin D1 in cultured bovine tracheal myocyte mitogenesis. Immunoblots using a polyclonal antibody against cyclin D1 showed the appearance of this protein 4 h after treatment with platelet-derived growth factor (PDGF), a potent mitogen for these cells. Immunoblots utilizing an antibody against the 110-kDa retinoblastoma protein (Rb), a downstream phosphorylation target of the cyclin D1/cyclin-dependent kinase 4 (cdk4) complex, showed reduced electrophoretic mobility of this protein as early as 8 h after PDGF treatment, suggesting phosphorylation of Rb by the cyclin D1/cdk4 dimer in vivo. Epidermal growth factor (EGF), a nonmitogen, failed to induce either cyclin D1 synthesis or Rb phosphorylation. PDGF treatment of cells transiently transfected with the full-length cyclin D1 promoter subcloned into a luciferase reporter increased luciferase activity almost threefold, demonstrating transcriptional activation of the cyclin D1 promoter with mitogenic stimulation. Finally, microinjection of individual myocytes with an affinity-purified antibody against cyclin D1 reduced the percentage of cells traversing S phase after serum stimulation, as assessed by fractional bromodeoxyuridine labeling (isotype control antibody, 0.74 +/- 0.10; anti-cyclin D1, 0.22 +/- 0.04; P = 0.0001). We conclude that 1) mitogenic stimulation of cultured bovine tracheal myocytes by PDGF induces cyclin D1 transcriptional activation and protein expression, 2) cyclin D1 expression is accompanied by Rb phosphorylation, which is evidence of increased cyclin D1-associated kinase activity in vivo, and 3) microinjection of anti-cyclin D1 antibodies inhibits cellular DNA synthesis, which is evidence that cyclin D1 is required for airway smooth muscle S phase traversal.

Animals↗

PubMed1997

Genotype distribution of estrogen receptor polymorphisms in men and postmenopausal women from healthy and coronary populations and its relation to serum lipid levels.

The cardiovascular protective effects of estrogen are known to be mediated by its beneficial effects on lipid metabolism and its direct actions on the vessel wall. The latter can be mediated by a specific receptor for estrogen present on smooth muscle cells and endothelial cells. The gene for the receptor (the classic estrogen receptor [ER]) has three known polymorphisms, Pvu II, Xba I, and B-variant polymorphisms, which are reportedly associated with receptor expression and altered receptor function and with some disorders including breast cancer, hypertension, and spontaneous abortion. However, the significance of genetic variations of the ER in vascular diseases has not been reported. We have examined the association between coronary artery disease (CAD) and the three polymorphisms in ER. Genotypes (P1/P2, X1/X2, and B-wild type/B-variant type) were determined in 87 men and postmenopausal women with myocardial infarction or angina pectoris whose lesions were confirmed by coronary angiography, as well as from 94 control individuals from the general population with no coronary heart disease and normal resting ECG. For B-variant polymorphism, all individuals examined had B-wild type, which contrasts with the reported allele frequency for B-variant type (0.1) in the white population. Genotype distributions and allele frequencies of Pvu II or Xba I polymorphisms were not significantly different between control subjects and patients (P > .05 for Pvu II or Xba I genotypes; P > .05 for Pvu II or Xba I allele frequencies). When the allele frequencies were analyzed separately by sex, there was still no statistically significant difference for both polymorphisms (P > .05 for men; P > .05 for women). No association was found between the polymorphisms and the angiographic severity of CAD. Total cholesterol, triglyceride, or HDL-cholesterol levels were not significantly different among ER genotypes. These findings suggest that the three polymorphisms in ER are not associated with the prevalence and severity of CAD and that the polymorphisms are unrelated to the serum lipid levels in control subjects and patients.

Adult↗

PubMed1997

A 192Arg variant of the human paraoxonase (HUMPONA) gene polymorphism is associated with an increased risk for coronary artery disease in the Japanese.

Recent reports have suggested that polymorphisms in the human paraoxonase (HUMPONA) gene may be a genetic risk factor for coronary artery disease (CAD) in white populations. However, this association has not yet been confirmed in other ethnic populations. We studied 75 Japanese patients with CAD, whose coronary lesions were confirmed by angiography, and 115 Japanese control subjects with no history of CAD and a normal resting electrocardiogram. The assays for genotyping the two polymorphisms in the HUMPONA gene (192Arg/Gln and 55Leu/Met) were based on changes in restriction enzyme digestion patterns. For codon 192, the frequencies of the Arg-coding allele (B allele) in both patients and control subjects were much higher than those from published results of whites (.26 to .31), and the difference between patients (.74) and control subjects (.59) was statistically significant (P = .002). The patient group had a higher proportion of Arg/Arg (B/B) homozygotes (52.0% vs 32.2%, P = .006). For codon 55, the frequencies of the Leu-coding allele in control subjects and patients were much higher (.91 and .93, respectively) than those published results for whites, but there was no difference between Japanese control subjects and Japanese patients. When subjects with the 55Leu/Leu genotype only were analyzed, 192Arg/Arg homozygotes were still significantly more frequent in the patients than in the control subjects (55.4% vs 37.2%, P = .024), and the frequency of the 192Arg allele was also higher in patients than control subjects (P = .013). Logistic regression analysis including conventional coronary risk factors revealed that 192Arg is an independent risk factor for CAD. Thus, in the Japanese, the association of CAD with the 192Arg variant of HUMPONA (B-type enzyme) is similar to that reported for whites, although the allele frequencies for 192Arg and 55Leu are much higher in the former than the latter population.

Adult↗

PubMed1997

Postoperative influences of surgical cryoablation for Wolff-Parkinson-White syndrome--a analysis of myocardial enzymes and function.

We evaluated postoperative myocardial enzymes and function associated with cryoablation in 20 patients with Wolff-Parkinson-White syndrome undergoing surgical treatment for a single left-sided accessory conduction pathway. Ten patients underwent endocardial atrial incision with cryoablation using CO2 at -60 degrees C for 120 sec (group A), while the remaining 10 patients did not receive cryoablation (group B). Levels of aspartate aminotransferase (GOT), lactate dehydrogenase (LDH), and creatine kinase (CK-MB) on postoperative days 1, 2, and 3 were higher in patients in group A than in group B (p < 0.05). However, mean values remained low (GOT, 120.5 IU/L; LDH, 1105.1 IU/L; CK-MB, 76.3 IU/L). No electrocardiographic changes were detected. Parameters of cardiac function, including cardiac index, stroke volume index, systemic vascular resistance, and ejection fraction, remained unchanged during the postoperative period in both groups. Furthermore, 201Tl cardiac scintigraphy demonstrated no evidence of myocardial perfusion defects due to cryoablation in group A. In conclusion, myocardial damage induced by cryoablation is very minor and is not associated with any clinical impairment of cardiac function.

Adult↗

PubMed1997

Ovarian response and FSH profile in cows following injection of various doses of inhibin antiserum.

Dose effect of inhibin antiserum on ovarian response and hormonal profiles were investigated. On day 12 of the estrous cycle (day 0 = estrus), 14 of 19 cows were given a single i.v. injection of 25 ml (n = 4), 37.5 ml (n = 5) or 50 ml (n = 5) antiserum against inhibin produced in a castrated male goat. The other 5 animals were given 50 ml castrated male goat serum (control serum). The animals in each group received a single i.m. injection of 0.5 mg prostaglandin F2 alpha analogue (PG) 48 hr following the serum injection. The population of follicles and ovulation rate (estimated by the number of corpora lutea) were examined by ultrasonography. Administration of inhibin antiserum consistently resulted in a significant (p < 0.01) increase in plasma concentrations of follicle-stimulating hormone (FSH) in inhibin-neutralized groups, although the increased FSH levels were sustained longer in 50-ml group than in the 25- and 37.5- ml groups. Levels in the circulating inhibin antibody titer were positively correlated with dosage of inhibin antiserum. A large number of antral follicles (> or = 4 mm in diameter) developed similarly after hypersecretion of FSH in all neutralized groups, coupled with a rise in plasma estradiol levels, while the number of large follicles (> or = 10 mm in diameter) on estrus showed a dose-dependent increase. Multiple ovulation (2 to 4) was recorded in all animals after injection of 50 ml inhibin antiserum, however all cows in the 25-ml group experienced only one ovulation and injection of 37.5 ml resulted in a variable number of ovulations (1 to 5). These results demonstrated that administration of inhibin antiserum on day 12, followed by injection of PG, was able to induce hypersecretion of FSH and subsequently multiple ovulations. The number of large follicles on estrus day and ovulations were affected by dosage of inhibin antiserum and were correlated with persistence of increased FSH levels or circulating antibody levels.

Animals↗

PubMed1997

Effects of repeated ether stress on the hypothalamic-pituitary-testes axis in adult rats with special reference to inhibin secretion.

Effects of ether stress on the hypothalamo-hypophysial-gonadal axis in adult male rats were examined. To clarify the role of adrenal glucocorticoids in gonadal function, the effects of adrenalectomy and Dexamethasone treatment were also investigated. Ether stress increased the plasma concentrations of ACTH and corticosterone, but decreased the plasma concentrations of LH, FSH, inhibin and testosterone. The pituitary responsiveness to LH-RH for LH release and testicular responsiveness to the endogenous LH for testosterone release were maintained in stressed rats. Adrenalectomy caused an increase in the plasma concentrations of ACTH, but decreased the plasma concentrations of LH, FSH and testosterone. Dexamethasone treatment in adrenalectomized rats recovered the levels of plasma gonadotropins to control levels. The concentration of plasma inhibin did not change in adrenalectomized rats, but it was decreased compared to control rats by Dexamethasone treatment. Treatments of Dexamethasone in intact male rats resulted in a decline in plasma levels of testosterone and inhibin without a decrease in the levels of LH and FSH, indicating the direct effect of Dexamethasone on the testes. These results indicate that increased ACTH secretion in stressed rats is probably due to hypersecretion of CRH from the hypothalamus, which suppresses gonadotropin secretion via the inhibition of LH-RH. The decreased levels of testosterone may be caused by a stress-induced decrease in plasma LH concentrations and increased secretion of corticosterone in the ether stressed rats. The low levels of plasma inhibin in stressed rats was also probably due to the direct effect of corticosterone on the Sertoli cells.

Adrenalectomy↗

PubMed1997

The pressor response induced by repeated injections of neostigmine into the central nervous system is desensitized in adrenalectomized, but not in intact rats.

To investigate whether or not pressor responses to repeated stimulation of central cholinoceptive neurons are desensitized, mean arterial blood pressure (MAP) and heart rate (HR) were measured following repeated injections of neostigmine, an acetylcholinesterase inhibitor, into the third cerebral ventricle in conscious, unrestrained intact or adrenalectomized (ADX) rats. Neostigmine (5 x 10(-9) or 5 x 10(-8) mol) in 1 milliliter saline increased MAP dose-dependently and increased HR in intact rats. The peak values in MAP and HR after three repeated injections at 4 hour intervals did not wane. Neostigmine (5 x 10(-8) mol) also increased MAP in ADX rats, and the peak values after the first injection were higher in the ADX rats than in the intact rats. The pressor responses to the second and third injection, however, were less than to the first injection in the ADX rats. HR responses to the repeated injections in the ADX rats were identical to those in the intact rats. These findings suggest that the adrenal gland plays a role in antagonizing the development of desensitization in the neostigmine-induced pressor response.

Adrenalectomy↗

PubMed1997

Ontogeny of inhibin secretion in the rat testis: secretion of inhibin-related proteins from fetal Leydig cells and of bioactive inhibin from Sertoli cells.

The ontogeny of inhibin secretion in the testis of rats was investigated. Testicular localization, content of immunoactive and bioactive inhibin and its molecular size in fetal and neonatal rats (from 16 days of gestation to 5 days of age) were determined. Strong immunostaining with an antiserum against a polypeptide of porcine inhibin alpha-subunit was noted in testicular interstitial cells from 16 days of gestation. Co-localization of inhibin alpha-subunit and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was observed in the interstitial cells until 2 days of age. Immunoreactive inhibin alpha-subunit in the interstitial tissue had disappeared by 5 days of age, although 3 beta HSD-positive cells were still detected. Weak immunostaining for the inhibin alpha-subunit was detected in the seminiferous tubules, probably in the cytoplasm of Sertoli cells, from 20 days of gestation onward. No inhibin alpha-subunit immunostaining was observed in germ cells throughout the experimental period. Testicular inhibin was detected at 16 days of gestation (49.5 +/- 6.7 pg per testis) by RIA. Testicular immunoreactive inhibin showed a tendency to increase during fetal life and levels were maintained at a similar value after birth (697.0 +/- 46.9 pg per testis at 5 days of age). Inhibin bioactivity and its molecular size in testicular homogenate was examined at 17 days of gestation and 0 and 5 days of age. Although no bioactivity was detected at 17 days of gestation, bioactivity was noted at 0 and 5 days of age (177.7 and 1303.9 pg per testis respectively). Immunoblot analysis with antiserum against inhibin alpha-subunit revealed only approximately 40 kDa molecular masses in the testis at 17 days of gestation, probably inhibin-related proteins, but not inhibin. At 0 and 5 days of age, a protein of 30 kDa molecular mass, possibly inhibin, was detected as well as material of approximately 40 kDa molecular mass. FSH in the plasma was first detected at 19 days of gestation (1197.0 ng/l), increased towards birth, and thereafter decreased (4588.5 +/- 572.3 ng/l at 21 days of gestation and 2400.0 +/- 179.6 ng/l at 5 days of age). These results indicate that Leydig cells in fetal and neonatal rats produce inhibin-related substances with no inhibin bioactivity, whereas Sertoli cells begin to produce inhibin during the perinatal period as a possible regulator of FSH secretion.

3-Hydroxysteroid Dehydrogenases↗

PubMed1997

[Minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass: a case report].

A new coronary artery bypass grafting of the left anterior descending coronary arteries (LAD) with in situ internal thoracic artery (ITA) bypass grafts through a limited anterior thoracotomy was performed in a 70-year-old [correction of 60] patient. The left ITA-LAD anastomosis was completed without cardiopulmonary bypass and postoperative angiography showed a patent anastomosis. With this minimally invasive approach, the procedure should provide the benefits of ITA grafting with rapid recovery short hospital stay without complication associated with cardiopulmonary bypass in selected cases.

Aged↗

PubMed1997

[Studies on residual cardiovascular dysfunction in patients receiving long-term antihypertensive treatment of calcium channel blockers: with special reference to left ventricular hypertrophy, and impairments of left ventricular diastolic function and carotid arterial distensibility].

Residual cardiovascular dysfunctions including left ventricular hypertrophy, and impairment of left ventricular diastolic function and carotid arterial distensibility were investigated in hypertensive patients treated with calcium channel blockers for more than 1 year. Ultrasonographic examinations of the heart and carotid artery were performed in patients treated with calcium channel blocker alone for more than 1 year (n = 45) and in age-, sex- and weight-matched control subjects (n = 29). The following parameters were obtained: left ventricular mass index, cardiac diastolic function (A/E ratio) and carotid arterial distensibility (Distens). Hypertensive subjects were re-examined under the same conditions with the same parameters after 10 +/- 5 months. Patients with hypertension revealed no significant changes in these three parameters after 10 +/- 5 months Patients with left ventricular hypertrophy (n = 20) revealed significant impairments in diastolic function and carotid arterial distensibility (A/E = 1.42 +/- 0.25, Distens = 2.4 +/- 1.3% kPa) compared to those without left ventricular hypertrophy (n = 25) (A/E = 1.18 +/- 0.29, Distens = 3.8 +/- 1.7% kPa, p < 0.05). Patients without left ventricular hypertrophy had significantly impaired cardiovascular functions compared to the normal control group (A/E = 1.03 +/- 0.27, Distens = 6.3 +/- 2.2% kPa, p < 0.05, p < 0.01 respectively). Therefore, only reduction of blood pressure with calcium channel blocker may not be enough to improve cardiovascular organ damage, especially in patients with residual left ventricular hypertrophy, and such residual functional deteriorations must be corrected probably with another pharmaceutical modality.

Aged↗

PubMed1997

[Three cases of recombinated gene in the ABO blood group system].

We found the AG allele in three cases (two cases are AGOA type and one case is A1AG type) out of unrelated 150 Japanese by amplified product length polymorphism technique for genotyping of ABO blood group system. The AG alleles amplified with allele-specific PCR method, were analyzed from exon 6 to 7 by direct sequencing. The AG allele was divided into suballees, AG1 and AG2. The AG1 and AG2 were revealed to have the same sequence as B allele in exon 6. In exon 7, however, the AG1 allele had the same sequence as A1 allele and the AG2 allele had hybrid sequence of B and OG allele.

ABO Blood-Group System↗

PubMed1997

[Composite arterial conduits with internal thoracic artery and radial artery for a myocardial revascularization].

From April 1996 to December 1996, 15 patients were submitted to myocardial revascularization using composite arterial conduit with internal thoracic artery (ITA) and radial artery (RA). The age ranged from 51 to 76 years (mean age, 65.7 years); Forty patients were male. All patients had double or triple vessel disease or LMT disease. We used 28 arterial conduits including 15 left ITAs, 15 RA, 9 right gastroepiploic artery and one inferior epigastric artery. 15 RAs were anastomosed to LITAs and 15 composite arterial conduits were constructed (branched in 15). There was no operative deaths. Early postoperative angiographic controls demonstrated 93.3% (14/15) patency of composite grafts in 14 of 15 patients. The composite arterial graft using ITA and RA is feasible and the anastomoses so performed are completely safe.

Aged↗

PubMed1997

[Pathological examination of radial artery--as a graft material for coronary artery bypass grafting].

To evaluate the usefulness of the radial artery (RA) as a graft material for coronary artery bypass grafting (CABG), the histologic studies of the RA were performed. Specimens were obtained from both sides of 10 RAs during the operations. The degree of arteriosclerosis was evaluated by two methods. The one was microscopic examination by a pathologist, while the other was used by NIH Image 1.57 system. Using this system, the pathological index of arteriosclerotic change was expressed as a ratio (Rx: internal luminal area/tunica media area) of the cross section. From the pathological view the tunica media of RA was rich in smooth muscle cells and poor in elastic fiber. And there was little arteriosclerosis in this artery. The mean Rx of the proximal side of RA was 0.177 +/- 0.033 and that of the distal side was 0.258 +/- 0.132. There was no significant difference between the two, but the proximal side of the RA was slightly larger than the distal. These results showed that RA has a low grade of arteriosclerosis. This was confirmed on microscopic examination. According to these results, the RA can be expected to be a suitable bypass material for CABG.

Aged↗

PubMed1997

[A simple technique for the genotyping of TH01 locus].

It is difficult to differentiate between type 9.3 and 10 at the TH01 locus. Therefore, we designed three primers including allele-specific primer for the type 9.3. Our primer sets gave shorter fragments ranging from 62 to 81 bp than those in other reports, allowing each allelic band to be resolved by 10% non-denaturing polyacrylamide gel electrophoresis and stained with SYBR Green I. TH01 typing was successfully applied to human remains such as sera, whole bloods and blood stains made about 80 years ago without extracting DNA from them. The simple and fast methods for TH01 typing as demonstrated herein will be useful in the field of forensic practice.

Base Sequence↗

PubMed1996

Induction of cyclin D1 by simian virus 40 small tumor antigen.

Cell-cycle progression is mediated by a co-ordinated interaction between cyclin-dependent kinases and their target proteins including the pRB and E2F/DP-1 complexes. Immunoneutralization and antisense experiments have established that the abundance of cyclin D1, a regulatory subunit of the cyclin-dependent kinases, may be rate-limiting for G1 phase progression of the cell cycle. Simian virus 40 (SV40) small tumor (t) antigen is capable of promoting G1 phase progression and augments substantially the efficiency of SV40 transformation through several distinct domains. In these studies, small t antigen stimulated cyclin D1 promoter activity 7-fold, primarily through an AP-1 binding site at -954 with additional contributions from a CRE site at -57. The cyclin D1 AP-1 and CRE sites were sufficient for activation by small t antigen when linked to an heterologous promoter. Point mutations of small t antigen between residues 97-103 that reduced PP2A binding were partially defective in the induction of the cyclin D1 promoter. These mutations also reduced activation of MEK1 and two distinct members of the mitogen-activated protein kinase family, the ERKs (extracellular signal regulated kinases) and the SAPKs (stress-activated protein kinases), in transfected cells. Dominant negative mutants of either MEK1, ERK or SEK1, reduced small t-dependent induction of the cyclin D1 promoter. SV40 small t induction of the cyclin D1 promoter involves both the ERK and SAPK pathways that together may contribute to the proliferative and transformation enhancing activity of small t antigen.

Animals↗

PubMed1996

Angiotensin II activation of cyclin D1-dependent kinase activity.

Angiotensin II (AII) binds to specific G protein-coupled receptors and is mitogenic in adrenal, liver epithelial, and vascular smooth muscle cells. Since the cyclin D1 gene encodes the regulatory subunit of the cyclin D1-dependent kinase (CD1K) required for phosphorylation of the retinoblastoma protein (pRB), an essential and rate-limiting step in G1 phase progression of the cell cycle, we examined the effect of AII on cyclin D1 expression and CD1K activity in the human adrenal cell line H295R. AII (10(-6) M) stimulated G1 phase progression within 12 h, with a maximal effect after 72 h. This action was antedated by the induction of cyclin D1 mRNA (3-fold), cyclin D1 nuclear protein abundance (4-fold), and CD1K activity (4-fold). AII induced cyclin D1 promoter activity 4-fold, via the AT1 receptor through an enhancer sequence at -954 base pairs. c-Fos and c-Jun bound the cyclin D1 -954 enhancer sequence, and the abundance of c-Fos within this complex was increased by AII treatment. AII induced extracellular signal-regulated kinase (ERK) activity 7-fold, and dominant-negative mutants of either p21(ras) or ERK reduced AII-stimulated cyclin D1 promoter activity. These findings suggest that AII may stimulate mitogenesis by increasing CD1K activity through a p21(ras)/ERK/activator protein 1 pathway.

Angiotensin II↗

PubMed1996

An impaired carotid sinus distensibility and baroreceptor sensitivity alter autonomic activity in patients with effort angina associated with significant coronary artery disease.

Baroreceptor sensitivity and carotid sinus distensibility were lower in patients with angina associated with significant coronary artery disease than in patients with vasospastic angina. Baroreceptor sensitivity was significantly correlated with carotid sinus distensibility in both groups of patients.

Angina Pectoris↗

PubMed1996

Rhotekin, a new putative target for Rho bearing homology to a serine/threonine kinase, PKN, and rhophilin in the rho-binding domain.

Using a mouse embryo cDNA library, we conducted a two-hybrid screening to identify new partners for the small GTPase Rho. One clone obtained by this procedure contained a novel cDNA of 291 base pairs and interacted strongly with RhoA and RhoC, weakly with RhoB, and not at all with Rac1 and Cdc42Hs. Full-length cDNAs were then isolated from a mouse brain library. While multiple splicing variants were common, we identified three cDNAs with an identical open reading frame encoding a 61-kDa protein that we named rhotekin (from the Japanese "teki," meaning target). The N-terminal part of rhotekin, encoded by the initial cDNA and produced in bacteria as a glutathione S-transferase fusion protein, exhibited in vitro binding to 35S-labeled guanosine 5'-3-O-(thio)triphosphate-bound Rho, but not to Rac1 or Cdc42Hs in ligand overlay assays. In addition, this peptide inhibited both endogenous and GTPase-activating protein-stimulated Rho GTPase activity. The amino acid sequence of this region shares approximately 30% identity with the Rho-binding domains of rhophilin and a serine/threonine kinase, PKN, two other Rho target proteins that we recently identified (Watanabe, G., Saito, Y., Madaule, P., Ishizaki, T., Fujisawa, K., Morii, N., Mukai, H., Ono, Y., Kakizuka, A., and Narumiya, S. (1996) Science 271, 645-648). Thus, not only is rhotekin a novel partner for Rho, but it also belongs to a wide family of proteins that bear a consensus Rho-binding sequence at the N terminus. To our knowledge, this is the first conserved sequence for Rho effectors, and we have termed this region Rho effector motif class 1.

Adaptor Proteins, Signal Transducing↗