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Biomedical subjects

G Watanabe

Publications and source records attributed to G Watanabe.

At least 289 records · Page 16Linked to original sources
PubMed1993

Third-time coronary artery revascularization.

Eighteen patients underwent a third coronary artery revascularization (rere-CABG) between 1983 and 1991. The factors necessitating rere-CABG were graft failure in 83% of the patients and progression of native coronary atherosclerosis in 17%. Mean interval between the second and third operation was 49.1 months. Median sternotomy and cardiopulmonary bypass (CPB) were used in 12 patients, a left thoracotomy approach was used in 6 (with CPB in 3 patients and without CPB in 3). The mean revascularization rate was 2.2 (grafts/patient). The internal thoracic artery was employed in 12 patients and the right gastroepiploic artery was used in one. Operative mortality was 11.1% (2 deaths). Non-fatal perioperative myocardial infarction, reexploration for bleeding, and respiratory failure occurred in one patient each. There were no other serious complications. Long-term follow-up was obtained in 15 of the 16 survivors. Four patients had recurrence of angina pectoris, and one late death due to myocardial infarction occurred. The myocardial event-free rate was 75% at 3.4 years. This experience indicates that a third coronary revascularization can be justified: operative approach and choice of graft material have to be individualized, but adequate long-term results can be obtained.

Aged↗
PubMed1993

Inhibition by indomethacin of the already accelerated secretion of inhibin and estradiol in equine chorionic gonadotropin-primed immature female rats.

In immature female rats, the secretion of ovarian inhibin and estradiol is greatly accelerated by equine chorionic gonadotropin (eCG) treatment. The present study has been carried out to determine whether or not the levels of the two hormones are inhibited by a single s.c.-injection of indomethacin (INDO) 24 h after eCG administration. The levels of ovarian hormones and gonadotropins were measured by double-antibody radioimmunoassay using 125I-labeled radioligands. The serum levels of inhibin and estradiol were considerably inhibited within 24 and 12 h, respectively, after INDO injection. In addition, the serum levels of follicle-stimulating hormone (FSH) after INDO injection remained lower than the basal levels before eCG treatment. The luteinizing hormone (LH) levels were significantly reduced within 12 h after INDO treatment. The results demonstrate that the levels of inhibin and estradiol, even in the situation where the production of both hormones is already accelerated by eCG pretreatment, are suppressed by an inhibitor of prostaglandin (PG) synthesis, suggesting that locally produced PGs may play a role in the regulation of the production of both hormones in the ovary.

Animals↗
PubMed1993

Age-related changes in blood concentrations of FSH, LH and testosterone and testicular morphology in a new rat sterile mutant with hereditary aspermia.

A new rat mutant showing aspermia was investigated. Groups of 4-7 mutant male rats were killed at 3, 5, 10, 15 and 25 weeks of age. Examination by microscope showed apparent abnormalities in the seminiferous epithelium from 3 weeks of age onward. Inclusion-like bodies were observed in the cytoplasm of pachytene spermatocytes from 3 weeks old and instead of spermiation, polynuclear giant cells were formed within the seminiferous epithelium after 5 weeks of age. Histological analysis of seminiferous epithelium of adult mutant rats also showed a marked decrease in the number of preleptotene, leptotene and pachytene spermatocytes and tubules containing only spermatogonia and Sertoli cells in the seminiferous epithelium increased with age. However, the combination of other cellular elements of germ cells in the seminiferous epithelium was similar to that in normal rats and the distribution rate of these seminiferous tubules was close to that of normal rats, indicating that cyclicity of seminiferous epithelium was still maintained in the mutant rats despite the lack of spermiation. Plasma concentrations of FSH and LH were significantly higher in the mutant male rats than in normal male rats at 5 and 10 weeks of age onward, respectively. Plasma concentrations of testosterone were lower in the mutant male rats than in normal male rats. Silastic capsules containing testosterone were implanted into the unilateral testis of adult mutant male rats and animals were autopsied 5 weeks later. However, intratesticular administration of testosterone did not affect restoration of spermatogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Evidence that inhibin is an important factor in the regulation of FSH secretion during the mid-luteal phase in cows.

To investigate the physiological importance of inhibin in the regulation of FSH secretion in cows, seven cyclic cows were treated with an inhibin antiserum raised against bovine 32 kDa inhibin in a castrated goat. The same animals treated with a castrated goat serum (control serum) served as controls. On day 12 of the oestrous cycle (day 0 = day of oestrus), four of seven cows were injected with 100 ml inhibin antiserum first, and the remaining three cows with 100 ml control serum first. Twelve days after the second oestrus following the first serum injection (42-46 days after the first serum injection), the former four cows were injected with control serum and the latter three with inhibin antiserum. Follicular development after the injections of control serum or inhibin antiserum was assessed by daily ultrasonographic examination. Treatment with inhibin antiserum resulted in a marked increase (P < 0.01) in plasma concentrations of FSH and oestradiol-17 beta but not LH or progesterone, compared with those after treatment with control serum. Plasma concentrations of FSH increased significantly (P < 0.01) at 8 h after injection of anti-inhibin serum when compared with the control value. Concentrations of FSH in the plasma remained high for 72 h, then declined to the control level by 84 h, concomitant with an abrupt decrease in the titre of free inhibin antibody in the plasma. High concentrations of oestradiol-17 beta were observed between 36 and 96 h after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Involvement of inhibin in the regulation of FSH secretion in prepubertal bulls.

To investigate the physiological importance of inhibin in the regulation of FSH secretion in prepubertal bulls, animals (6-month-old) were passively immunized against inhibin. Five animals were given an i.v. bolus injection of 50 ml inhibin antiserum raised against bovine 32 kDa inhibin in a castrated male goat, and four bulls were given the same amount of castrated male goat serum (control serum) as controls. Treatment with the inhibin antiserum resulted in a marked increase (P < 0.01) in plasma concentrations of FSH within 12 h compared with control animals, and FSH levels in immunized animals remained high until 168 h after the injection. Concentrations of plasma LH and testosterone in the immunized animals were not different from those in the control animals. The present findings provide strong evidence that inhibin plays an important role in the inhibitory regulation of FSH secretion in prepubertal bulls.

Animals↗
PubMed1993

Suppression of basal secretion of FSH inhibits follicular development and maturation during the oestrous cycle of the rat.

The role of basal FSH secretion during the rat oestrous cycle in regulating ovulation was examined by suppressing FSH secretion using charcoal-treated porcine follicular fluid (pFF). Although 0.5 ml pFF given at 05.00 and 11.00 h on the day of pro-oestrus had no effect on ovulation, 0.5 ml pFF given five times at 6-h intervals from 11.00 h on dioestrus to 11.00 h on pro-oestrus completely eliminated ovulation on the morning of the next oestrus. When 0.25 ml pFF was given on the same schedule, all animals ovulated a significantly decreased number of oocytes (9.0 +/- 0.8) at the next oestrus. During the period of pFF treatment, the number of follicles capable of ovulating in response to human chorionic gonadotrophin (hCG) decreased (7.6 +/- 0.7 at 05.00 h on pro-oestrus) and plasma levels of oestradiol showed a peak level 6 h later than in controls treated with 0.5 ml steroid-free porcine serum. Treatment with pFF suppressed plasma FSH concentrations in a dose-dependent manner, although plasma LH was inhibited irregularly. Supplementary administration of LH throughout the treatment period and 0.5 ml pFF resulted in ovulation of one to three oocytes in response to hCG in only three out of ten animals. These results suggest that basal secretion of FSH during the rat oestrous cycle plays an essential role in follicular development and maturation towards ovulation, and that the levels of FSH secretion may contribute to the maturation of normal numbers of follicles for ovulation.

Animals↗
PubMed1993

[A successful case report of coronary bypass grafting by utilizing inferior epigastric artery, gastroepiploic artery and bilateral internal thoracic artery].

We performed coronary artery bypass grafting with the bilateral internal thoracic artery (ITA), right gastroepiploic artery (RGEA) and inferior epigastric artery (IEA) on a 53-year-old patient who was associated with familiar hypercholesterolemia. The IEA was extended with right ITA as a composite graft and sequentially anastomosed to the right coronary artery and distal branch of the right coronary artery. Both the LITA to the left anterior descending artery and the RGEA to the circumflex artery were used as in situ graft. The postoperative coronary angiogram showed all the graft patient.

Abdominal Muscles↗
PubMed1993

[Clinical effect and characteristics of low dose leucovorin and high dose 5-FU therapy in patients with recurrent gastric cancer--a new method of biochemical modulation].

The biochemical modulation of 5-fluorouracil (5-FU) and leucovorin (LV) has resulted in a remarkable increase of the response rate in patients with colorectal cancer. Recently, in the treatment of gastric cancer this biochemical modulation has been introduced into clinical practice and has also achieved good antitumor activity. A review of the literature indicates that 5-FU/LV therapy for gastric cancer is effective only when LV is administered at high doses (200 mg-500 mg/m2), and the efficacy of low dose LV (20 mg/m2) administration with the combination of high dose 5-FU is still unknown. Thirty-five patients with measurable recurrent gastric cancer received low dose LV and high dose 5-FU for 4 days. The schedule was as follows: iv injection of low dose leucovorin (20 mg/m2) and from one hour later 2-hour infusion of high dose 5-FU (700 mg/m2). This new treatment for recurrent gastric cancer achieved a response rate of 40.0%, and 80.0% of the patients with pronounced palliative effects measured as recurrence-related symptoms. It is very rare for 7 out of 8 patients (87.5%) to be relieved of obstructive jaundice, and we now prefer this therapy to percutaneous transhepatic biliary drainage in patients with jaundice. The toxicity of this biochemical modulation is leukopenia, stomatitis and diarrhea, and the number of patients with toxicity over grade 3 was 5 (14.3%). There was no treatment-related death.

Adult↗
PubMed1992

Indomethacin inhibits the secretion of inhibin and oestradiol-17 beta stimulated by pregnant mare serum gonadotrophin in the immature female rat.

The involvement of prostaglandins (PGs) in the regulation of inhibin and oestradiol-17 beta secretion from the ovary was studied by determining the effects of indomethacin and/or pregnant mare serum gonadotrophin (PMSG) on the levels of ovarian hormones in immature female rats. An increase in serum and ovarian levels of inhibin and oestradiol-17 beta was observed with a reciprocal reduction in serum follicle-stimulating hormone (FSH) levels from within 26 to 50 h after a single injection of 5 IU PMSG (s.c.) when the rats were 26 days of age. Administration of indomethacin to suppress PGs synthesis, simultaneously with PMSG, resulted in a substantial reduction in the levels of ovarian PGF2 alpha and serum inhibin and oestradiol-17 beta, which were both enhanced by PMSG treatment, 24 h after treatment with drugs. Indomethacin also reduced the basal serum level of inhibin. In the indomethacin-treated animals, the serum level of FSH was significantly increased regardless of the treatment with PMSG, indicating that the negative feedback regulation between FSH and inhibin is operating in these animals. These results demonstrate the inhibitory effects of indomethacin on PMSG-enhanced inhibin and oestradiol-17 beta production, suggesting that PGs play a regulatory role in the secretion of inhibin and oestradiol-17 beta from the gonadotrophin-stimulated ovary.

Animals↗
PubMed1992

Role of brain histamine H1- and H2-receptors in neostigmine-induced hyperglycemia in rats.

We previously reported that when neostigmine, an inhibitor of acetylcholine esterase, was injected into the third cerebral ventricle, the concentration of hepatic venous plasma glucose was increased via central muscarinic receptors in anesthetized rats. To determine whether brain histamine receptors are involved in cholinergic system transmission with regard to central nervous system (CNS)-mediated glucoregulation, we examined the effects of the H1 receptor antagonist pyrilamine and the H2 receptor antagonist ranitidine on neostigmine-induced hyperglycemia in anesthetized rats. The injection of pyrilamine (5 x 10(-9)-5 x 10(-7) mol) into the third cerebral ventricle suppressed hyperglycemia induced by intraventricular injection of neostigmine (1 x 10(-9) mol) in a dose-dependent manner. Injection of ranitidine (5 x 10(-9)-5 x 10(-7) mol) into the third cerebral ventricle did not suppress the hyperglycemia induced by neostigmine, but enhanced it in a dose-dependent manner. These findings suggest that neostigmine-induced CNS-mediated hyperglycemia is transmitted by not only brain cholinergic muscarinic receptors but also in part by histamine H1 receptors.

Animals↗
PubMed1992

Changes in peripheral levels of bioactive and immunoreactive inhibin, estradiol-17 beta, progesterone, luteinizing hormone, and follicle-stimulating hormone associated with follicular development in cows induced to superovulate with equine chorionic gonadotropin.

Changes in concentrations of bioactive and immunoreactive (ir-) inhibin, estradiol-17 beta, progesterone, LH, and FSH in peripheral blood were determined in cows induced to superovulate with eCG. The pattern of follicular growth was also characterized by daily ultrasonographic examination. Hormonal profiles and follicular development during the intact estrous cycle of the same animals before eCG treatment served as controls. Equine CG increased the number of follicles of various sizes (small, greater than or equal to 4 less than 7, medium, greater than or equal to 7 less than 10; large, greater than or equal to 10 mm in diameter) by 4 days after administration. The second growth of large follicles occurred within 1 day after superovulation. Inhibin bioactivity in jugular vein blood was detectable 48 h after eCG injection (44 h before LH peak), whereas it was not detected before administration of eCG or during control cycles. Circulating levels of bioactive inhibin further increased during the two waves of growth of large follicles. The highest activity of inhibin was noted at the time of the preovulatory LH peak (0 h). Thereafter, bioactivity of inhibin in peripheral plasma dropped from 0 to 24 h after the LH peak, and the activity increased again at 72 h compared to the value at -44 h. Plasma levels of ir-inhibin showed a pattern similar to changes in bioactive inhibin in the eCG-treated cows. Plasma concentrations of estradiol-17 beta also increased concomitantly with two waves of growth of large follicles. There was no correlation between plasma levels of progesterone and inhibin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Heart transplantation, assist devices, and cardiomyoplasty.

Allograft replacement of the heart in pediatric patients has gained growing interest within the spectrum of cardiac transplantation. Here and in other age groups, new immunosuppressive agents are under investigation, hopefully providing more selective reduction of the immune response with lower side effects compared with conventional therapy. Many clinical investigators and basic scientists are working to understand, prevent, and possibly treat chronic cardiac allograft rejection, one of the major threats in long-term survivors. Within the scope of mechanical assist device application, bridge to transplantation does provide the best results. New developments include emergency treatment of cardiogenic shock by an intravascular left ventricular assist device and cardiopulmonary bypass, both designed as life support systems. Clinical studies on permanent implants of ventricular assist devices are on the way. As another alternative to heart transplantation, dynamic cardiomyoplasty using the latissimus dorsi muscle has gained increasing clinical attention. Results relating to clinical and hemodynamic improvement, however, remain conflicting, and long-term results are not yet available.

Assisted Circulation↗
PubMed1992

[Current treatment of Wolff-Parkinson-White syndrome and ventricular tachycardia: surgical ablation versus catheter ablation?].

From November 1973, 454 patients with Wolff-Parkinson-White syndrome underwent surgical ablation of accessory pathways. Overall curative rate was 94% in our series including 65 cases of simultaneous surgical repair for combined heart diseases. In recent months, radiofrequency catheter ablation was applied in 7 cases. There has been 2 failures, which have taken more than 2 hours of radiation exposure and have required surgery. There has been 47 patients who underwent surgical ablation for non-ischemic ventricular tachycardia. Forty cases (85%) had a successful outcome of surgical ablation and another 2 cases required DC catheter ablation postoperatively to eliminate ventricular tachycardias. In conclusion, radiofrequency ablation of WPW syndrome in patients without combined heart disease or multiple accessory pathways is feasible. Surgical ablation is effective and safe technique compared with catheter ablation in patients with ventricular tachycardia.

Adolescent↗
PubMed1992

[Prospective randomized trial comparing modified FAM (5-fluorouracil (5-FU) + adriamycin + mitomycin C) versus 5-FU alone for the treatment of non-resectable pancreatic and biliary tract carcinomas (the 1st trial in non-resectable patients). Study Group of Surgical Adjuvant Therapy for Carcinomas of the Pancreas and Biliary Tract].

The modified FAM (5-fluorouracil (5-FU) + adriamycin (ADR) + mitomycin C (MMC)) therapy (FAM group) was compared with 5-FU mono-therapy (F group) by multi-institutional randomized trial in the patients with cancer of the pancreas or the biliary tract who underwent non-resection. The patients in FAM group received 6 mg/m2 of i.v. MMC during operation, 310 mg/m2 of i.v. 5-FU for 5 days in the 1st and 3rd postoperative weeks and 12 mg/m2 of i.v. ADR in the 2nd postoperative week. Those in F group received only 5-FU course in the administration schedule of FAM group. Among the cases which completed respective whole administration schedules. 35 cases in FAM group and 36 in F group, better effect than partial response (PR) was observed in neither groups, and there was no significant difference between groups with respect to overall/each disease survival duration, progression-suppressed duration and clinical effect. Primary adverse effects were alimentary symptoms and hepatic dysfunction, neither of which was serious, and there was no difference between groups except that hair loss was observed in more cases in FAM group (p less than 0.05). Results in FAM group did not statistically surpass those in F group, but a tendency was observed that FAM group was better than F group in terms of survival duration and clinical effect for cancer of the gall-bladder.

Adult↗
PubMed1992

[Basic study of myocardial coagulation by intraoperative laser ablation: in the presence and absence of blood].

To investigate whether the efficacy of laser ablation therapy is affected by the color of the target organ, we irradiated 9 canine hearts through the epicardium with Nd-YAG laser (200 J, 400 J), and compared coagulated myocardial volume in the beating heart (reddish) with that in the stopped heart (whitish) infused with 0 degrees C saline (cardioplegic model) via a coronary artery. The coagulated myocardial volume of the beating heart was significantly larger than that of the arrested heart, indicating the YAG laser energy is absorbed by red myocardium to greater extent than it is by white myocardium. In conclusion, during intraoperative laser ablation, the presence or absence of blood in cardiac tissue is an important factor for safe irradiation.

Animals↗