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Biomedical subjects

G Watanabe

Publications and source records attributed to G Watanabe.

At least 307 records · Page 17Linked to original sources
PubMed1991

Ovarian follicular dynamics and concentrations of oestradiol-17 beta, progesterone, luteinizing hormone and follicle stimulating hormone during the periovulatory phase of the oestrous cycle in the cow.

Changes in the plasma concentration of oestradiol-17 beta, progesterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were characterized during the transition from the luteal to the follicular phase, the periovulatory period and the early luteal phase in five cycling cows. The pattern of growth and the regression of follicles and corpora lutea in the ovary of the same animals were also assessed by daily ultrasonographic examinations. Two waves of follicular growth (ovulatory and non-ovulatory) occurred in all animals. The ovulatory follicular wave started from 4 days before the preovulatory surges of LH and FSH and the wave of next growth of a dominant follicle (non-ovulatory follicle) started within one day after ovulation. Changes in plasma levels of oestradiol-17 beta correlated well with the growth of both ovulatory and non-ovulatory dominant follicles. Suppression of FSH concentration during the follicular phase was inversely related to the increase in plasma concentration of oestradiol-17 beta. These results suggest that, in the cow, ovulatory dominant follicles suppress FSH secretion by increasing the concentration of oestradiol-17 beta (and probably also inhibin) during the follicular phase.

Animals↗
PubMed1991

Seasonal changes in plasma concentrations of immunoreactive inhibin and testicular activity in male Japanese monkeys.

Seasonal changes in plasma immunoreactive (ir-) inhibin, testosterone, LH, and FSH concentrations were examined in five sexually mature male Japanese monkeys (Macaca fuscata fuscata) housed indoors individually, to explore the reproductive cyclicity in the male. Blood samples were collected monthly throughout one year, and testicular size, semen volume, and number of sperm in the semen were ascertained at the same time in the same animals. Semen samples were obtained by penile electrostimulation. The results showed a clear seasonal increase in all parameters: plasma ir-inhibin, testosterone, testicular size, semen volume, and total number of sperm in the liquid portion of the semen during the autumn and winter months in synchrony with the natural breeding season. In contrast, plasma LH and FSH remained unchanged throughout the year, although plasma FSH tended to increase during the breeding season concomitant with an increase in plasma ir-inhibin. A significant positive correlation between FSH and ir-inhibin was observed in two of five monkeys. The positive correlations between plasma ir-inhibin and testicular activities during both the developing and regressing phases of the testicular cycle indicate that plasma ir-inhibin is a useful indicator of testicular activity as well as an indicator of Sertoli cell function in the Japanese monkey.

Animals↗
PubMed1991

Ventricular assistance by right free wall dynamic cardiomyoplasty following acute right heart failure in canines.

The efficacy of right ventricular assistance provided by electrically conditioned skeletal muscle was studied in 17 canines. The right ventricular free wall was made ischemic and akinetic by ligating all coronary branches supplying it. The latter procedure led to deterioration of hemodynamic parameters. After that, 14 canines were divided into two groups: group 1 (n = 8) was observed without cardiomyoplasty for 2 hours; group 2 (n = 6) underwent right ventricular dynamic cardiomyoplasty with the conditioned left latissimus dorsi. The deterioration in hemodynamic parameters in group 1 showed no further significant change during the period of observation. In group 2, right ventricular function was augmented by cardiomyoplasty, as shown by a significant increase in right ventricular and pulmonary artery pressures. In addition, decreased CVP suggested improved right ventricle (RV) filling. Right ventricular function curves obtained by volume loading in a further group of three canines, group 3, also demonstrated improved right ventricular function. Thus right ventricular dynamic cardiomyoplasty appears to contribute significantly to right ventricular function in a model of acute right heart failure.

Acute Disease↗
PubMed1991

Marked seasonal changes in response to the negative feedback action of estradiol on luteinizing hormone secretion in the female Japanese monkey.

The seasonal changes in response to the negative feedback action of estradiol on LH secretion were studied in two groups of ovariectomized Japanese monkeys (Macaca fuscata fuscata; n = 6). Blood samples were collected two to three times a week, and changes in serum concentrations of LH, estradiol, and progesterone were examined. Before ovariectomy (OVX), serum LH was maintained at about 320 pg/ml regardless of the season (breeding season: autumn and winter). After OVX and simultaneous treatment sc with a Silastic implant of estradiol during the first breeding season, serum LH increased rapidly and remained high. As spring arrived, serum LH decreased abruptly and remained low. The removal of implants during the subsequent nonbreeding season resulted in an increase in serum LH similar to that during the previous breeding season after OVX and estradiol treatment. After the reinsertion of implants during the same nonbreeding season, serum LH reverted to previous low levels. As autumn arrived (second breeding season), serum LH rose again and remained high under the presence of implants. In the first subset of animals (n = 3), the implants were left in place until the subsequent mid-nonbreeding season when they were removed, and reinserted during the same non-breeding season. The findings closely corresponded to the previous results. In these animals, the implants were removed during the third breeding season, which resulted in a significant increase in serum LH. The second subset of animals (n = 3) underwent removal of implants during the second breeding season, which resulted in a further increase in serum LH, but the difference was not significant. In both subsets of animals, the timing of the increase and decrease in serum LH under the presence of implants virtually coincided with the onset and end of the breeding season in ovary-intact animals. Serum estradiol after OVX was maintained at levels similar to those in intact animals (80-100 pg/ml) under the presence of implants, but removal of implants resulted in decrease in serum estradiol to around 30 pg/ml within 1 week. Serum progesterone after OVX was maintained at low levels (less than 0.2 ng/ml) regardless of the presence of estradiol implants. These results clearly indicate a marked seasonal difference in serum LH concentrations in ovariectomized monkeys in response to constant serum estradiol. It is suggested that seasonal breeding of the Japanese monkey is governed by biannual changes in the response of the hypothalamo-hypophysial axis to the negative feedback action of estradiol.

Animals↗
PubMed1991

An evaluation of efficacy of cigarette smoking cessation in preventing low levels of serum high-density lipoprotein (HDL) cholesterol.

Correlation of serum high-density lipoprotein cholesterol (HDL-C) with cigarette smoking and alcohol consumption habit was investigated in 562 male office workers aged 31 to 60 yr. HDL-C concentrations were found to be positively associated with alcohol consumption in subjects with relative weight below 10%, but a positive association was not observed in obese subjects having relative weight of 10% or above. In contrast, HDL-C levels were significantly lower in smokers than in non-smokers regardless of obesity. The effectiveness of smoking cessation in preventing low levels of serum HDL-C was estimated by comparing prevalence rates of HDL-C levels lower than an arbitrarily determined HDL-C cutoff value in smokers with those in non-smokers. The estimation was made with unadjusted subjects and also with subjects adjusted for age, relative weight and alcohol consumption. The effectiveness was found to be considerably high in heavy smokers having lower HDL-C levels (less than or equal to 35 mg/dl) with or without hypercholesterolemia (greater than or equal to 220 mg/dl) and further remarkably high in all smokers having hypertriglyceridemia (greater than or equal to 300 mg/dl) besides lower HDL-C levels. It is therefore expected that health education focused on stopping smoking can produce favorable alterations in HDL-C for preventing coronary heart disease, especially in heavy smokers having low serum HDL-C levels concomitant with hypercholesterolemia and/or hypertriglyceridemia.

Adult↗
PubMed1991

[Treatment of cases of cardiac surgery complicated with malignant neoplasms].

There were 10 (1.2%) cases of cardiac surgery complicated with malignant neoplasm among the total 863 cases of cardiac surgery in our hospital and 8 cases were treated also surgically against the neoplasms before and after the cardiac surgery. They all underwent coronary artery bypass grafting, and in one case concomitant mitral valve replacement and abdominal aortic aneurysm resection were carried out. The variety of the neoplasms in these cases were carcinomas of the stomach, pancreas, esophagus, renal pelvis, bile duct, colon and urinary bladder, and pleural mesothelioma. These patients were discharged without operative death or major complication, and there was only one evidence of recurrence among the eight cases treated surgically for the neoplasms. It was considered that patients who have critical cardiac problem also bearing neoplasmic combination could be treated excellently by means of both surgical measures.

Aged↗
PubMed1990

Immunoreactive inhibin levels in peripheral blood during the breeding season in the female Japanese monkey.

Serum levels of immunoreactive inhibin as well as FSH, LH, estradiol-17 beta, and progesterone were measured by RIA in four mature female Japanese monkeys (Macaca fuscata fuscata) during the breeding season and subsequent transition into the nonbreeding season. During the breeding season, each monkey showed 2-6 ovulations, which were inferred from underlying endocrine events. The concentrations of serum inhibin increased during the luteal phase, but were low during the follicular phase. Such changes in serum inhibin levels correlated positively with those in serum progesterone levels. Basal levels of serum inhibin also increased during the breeding season, decreased during transition from the breeding season, and were low during the nonbreeding season. The parallel change in serum levels of inhibin and progesterone together with the increased basal levels of serum inhibin during this period suggests that both the CL and antral follicles are sources of circulating inhibin. Decreases in serum FSH levels during the luteal phase suggest that secretion of FSH is controlled by an inhibitory action of ovarian inhibin in addition to steroid hormones.

Animals↗
PubMed1990

Changes in circulating inhibin levels during pregnancy and early lactation in the Japanese monkey.

Changes in immunoreactive (ir-) inhibin concentrations in serum throughout pregnancy and early lactation up to one month after parturition were characterized in 6 Japanese monkeys (Macaca fuscata fuscata) by a heterologous radioimmunoassay (RIA) based on a bovine RIA. Serum levels of FSH, LH/monkey chorionic gonadotropin (mCG), estradiol-17 beta, and progesterone were also monitored for the entire period. Ir-inhibin levels in the serum were low (under 0.5 ng/ml) before conception. Three marked increases in serum ir-inhibin levels were found during pregnancy. The first increase was noted during early pregnancy, with a peak (2.2 +/- 0.2 ng/ml) at Day 22 of pregnancy (Day 0 = day of LH surge). The second increase was noted after Day 38 until Day 72 of pregnancy, when a peak value was noted (19.0 +/- 1.4 pg/ml). Plateau levels were maintained until late pregnancy, and a final rise was evident near the term with a peak (36.7 +/- 3.8 ng/ml) at Day 158 of pregnancy, 5 days before parturition. After parturition, ir-inhibin levels in the serum plummeted to nonpregnant levels within one day, and were maintained during early lactation. The first rise in serum inhibin during pregnancy was parallel to the rise of mCG and estradiol-17 beta, and the second and third rise were well correlated with serum estradiol-17 beta. Serum FSH was maintained at low levels throughout pregnancy, followed by a slight increase after parturition when serum inhibin decreased abruptly. Both bioactivity and immunoreactivity of inhibin were detected in the placental homogenates obtained at 120 days of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Thermally controlled laser irradiation of the myocardium with intraoperative ultrasound monitoring.

We used intraoperative ultrasonography (IOUS) to study the feasibility and safety of Nd:YAG laser irradiation of the myocardium in 26 canine left ventricular segments. During the laser irradiation process, the myocardial temperature was monitored and surface cooling was used. Afterward, intraoperative ultrasonographic scans, which enabled the evaluation of the irradiated lesions, were compared with cross sections made through the tissues. The total dose of laser energy ranged from 200 to 3,600 joules, and the estimated volume of irradiated lesions ranged from 76.8 to 2590 mm3. There were significant correlations between the laser discharge output (in joules [J]) and the irradiated lesion volume (P less than 0.001), and between the laser energy density (in J/mm2) and the depth of the lesions (P less than 0.01). Macroscopic examination of the cross sections of irradiated myocardium revealed that the lesions were well-demarcated, but not charred or perforated. Thus, we could obtain a satisfactorily large zone of laser photocoagulation without inducing tissue damage, if surface cooling was used and the myocardial temperature was monitored. IOUS was successful in visualizing and locating the irradiated lesions that were seen as hypoechoic, clearly outlined nodules. We submit that this study has established the technical feasibility and dose-response relationship of thermally controlled laser irradiation, and has demonstrated the usefulness of IOUS for the precise localization and monitoring of such laser treatment.

Animals↗
PubMed1990

Effects of electrical stimulation of the medial basal hypothalamus on the in vivo release of luteinizing hormone-releasing hormone in the prepubertal and peripubertal female monkey.

In this study the hypothesis that the LHRH neurosecretory system of the prepubertal female monkey has the capacity to function in a manner comparable to that of monkeys in more mature stages of development was tested. Using push-pull perfusion in the stalk-median eminence, effects of electrical stimulation of the medial basal hypothalamus on in vivo LHRH release were determined in conscious prepubertal, early pubertal, and midpubertal monkeys. After a 180-min period of baseline sample collection, electrical stimulation was applied six times at 90-min intervals via a monopolar electrode, the tip of which was 1-2 mm rostro-dorsal to the perfusion site. Control experiments were performed in the same manner, but without electrical stimulation. During control perfusions, the mean LHRH level remained stable. Mean (+/- SEM) LHRH release for the entire perfusion period in control experiments was 0.5 +/- 0.2, 2.4 +/- 0.4, and 2.2 +/- 0.7 pg/ml.10 min for the prepubertal (n = 6), early pubertal (n = 4), and midpubertal (n = 6) groups, respectively. Mean LHRH release in the prepubertal group was significantly lower than that in either of the older groups (P less than 0.05). In contrast, in all three age groups, repeated electrical stimulation of the medial basal hypothalamus resulted in 1) a short latency increase in LHRH release occurring within 20 min after each stimulation, and/or 2) a gradual increase in mean LHRH release over several hours. In the prepubertal group (n = 4), mean LHRH levels were 0.8 +/- 0.5 pg/ml.10 min during the 90 min before the first electrical stimulation and increased to 6.1 +/- 2.9 pg/ml.10 min during the 90 min after the sixth stimulation. This degree of responsiveness was similar to that of the older age groups. Mean LHRH levels before stimulation were 1.3 +/- 0.6 and 2.4 +/- 1.1 pg/ml.10 min in the early pubertal (n = 5) and midpubertal (n = 5) groups, respectively, and increased to 7.8 +/- 3.5 and 6.0 +/- 1.8 pg/ml.10 min, respectively, after the sixth stimulation. These increases in LHRH concentration with electrical stimulation were significant for all three age groups (P less than 0.03-0.001), while there were no significant differences between age groups. The temporal patterns of these responses suggest that electrical stimulation elicits LHRH release with a similar magnitude in all three age groups by 1) depolarizing LHRH neurons directly, and/or 2) stimulating multineuronal systems that synapse with LHRH neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Dynamics of ovarian inhibin secretion during the oestrous cycle of the rat.

Plasma and ovarian concentrations of inhibin were determined at 3-h intervals throughout the 4-day oestrous cycle of rats by a radioimmunoassay (RIA) based on a bovine RIA. Plasma concentrations of LH, FSH, progesterone, testosterone, oestradiol-17 beta, and pituitary contents of FSH and LH were also determined during the cycle. Plasma levels of inhibin showed a marked increase on the morning of oestrus and the afternoon of metoestrus, and a further increase was noted on the morning of pro-oestrus. These increases in plasma levels of inhibin were probably due to the following three events in the ovary, follicular recruitment on the morning of oestrus, selection of follicles on the day of metoestrus, and final maturation of follicles for ovulation on the morning of pro-oestrus with an increase in oestradiol-17 beta secretion. A striking decrease in inhibin secretion occurred during the process of ovulation after the preovulatory gonadotrophin surge on the afternoon of pro-oestrus. Basal levels of plasma FSH gradually decreased from metoestrus to pro-oestrus as plasma levels of inhibin increased. There was a significant inverse relationship between plasma levels of FSH and inhibin throughout the oestrous cycle (r = -0.51). The present findings suggest that changes in the plasma levels of inhibin during the oestrous cycle provide a precise indicator for follicular recruitment, selection and ovulation, and that changes in concentrations of oestradiol-17 beta in the plasma are associated with follicular maturation.

Animals↗
PubMed1990

[Treatment of Wolff-Parkinson-White syndrome associated with asthma].

We performed division of accessory pathways in five asthma patients associated with Wolff-Parkinson-White (WPW) syndrome, for whom the administration of a beta-blocker for the tachycardia is contraindicated, and the administration of bronchodilators for the asthma attack may cause premature ventricular contractions. As a result, the tachycardic attacks disappeared postoperatively, both at rest and following administration of bronchodilators. Radical treatment of WPW syndrome by division the accessory pathway is considered to be necessary for the safe treatment of asthma.

Adrenergic beta-Antagonists↗
PubMed1990

[A successful surgical treatment of WPW syndrome associated with tricuspid atresia].

The occurrence of both tricuspid atresia and WPW syndrome is quite rare. To our knowledge, only two operated cases have been reported. In this report, a 8-year-old boy with this combination was reported. Tachycardia via the right side accessory pathway was for the first time pointed out after Kreutzer's operation. Epicardial mapping showed the earliest excitation at the right free wall. When fatty tissue around this area was removed by CUSA, a large cardiac vein appeared. By holding this vein with a forceps, the delta wave disappeared temporarily. ACP seemed to be present near this vein. Permanent disappearance of the delta wave was obtained after ligation and division. Four months after surgery, he is free from tachycardia attacks.

Child↗
PubMed1990

[Cryosurgical treatment of atrial tachyarrhythmia with atrial flutter].

Two cases of atrial tachyarrhythmias with atrial flutter requiring cryosurgical treatment are reported. In two cases, preoperative electrophysiological studies revealed supraventricular reentrant tachyarrhythmias during atrial flutter and showed enhanced conduction through the AV node that conducted atrial impulses rapidly to the ventricle. Based on intraoperative endocardial mapping, the earliest excitation site was localized along the AV node and His bundle during supraventricular tachyarrhythmias in one case. The cryosurgical treatment was administered at Koch's triangles and in one case additionally at coronary sinus. After the operation, supraventricular tachyarrhythmias were not inducible and no clinical recurrences have occurred. Normal atrioventricular conduction was preserved in two cases. We concluded that cryosurgical treatment is useful for the treatment of the atrial tachyarrhythmias.

Adult↗
PubMed1990

[Surgical treatment of ventricular tachycardia after radical correction of tetralogy of Fallot].

The patient was 21 year-old male with recurrent sustained VT following complete repair of tetralogy of Fallot. He underwent complete repair of tetralogy of Fallot at the age of 3. Eight years after the operation, he first noted episode of tachycardia. Sustained VT was first documented 15 years after operation, and he required direct-current cardioversion for this tachycardia. Because of life threatening arrhythmia he was transferred to our hospital for surgical management. Sustained VT was induced and found to originate from the inflow-septal and outflow area of right ventricle. During the operation only right outflow type tachycardia could be induced by programmed stimulation. Diastolic fractionated local electrical activity, which suggested a reentrant circuit, was recorded at the outflow epicardial area. The outflow muscle (2 X 2 cm) showing the earliest excitation during VT was excised with cryocoagulation at the outflow tract. The resected area was closed with a Gore-Tex patch using continuous sutures. Another cryocoagulation was applied to the inflow-septal area prophylactically. After surgery, a so-called non-clinical VT was inducible, however this VT could be prevented by antiarrhythmic drugs. No spontaneous episodes of VT have been postoperatively observed for 2 months.

Adult↗
PubMed1990

[Surgical management of aneurysm of the ascending aorta with aortic insufficiency].

Twelve patients had elective surgical treatment for the aneurysm of the ascending aorta with aortic insufficiency at the Kanazawa University School of Medicine between 1976 and 1987. There were 9 men and 3 women aged from 26 to 39 years (mean, 33.0 years). Seven patients had a Marfan's syndrome and 6 of these patients also had aortic dissection. Three patients had aortic valve replacement plus supracoronary tube graft (Wheat's operation) and the other 9 patients underwent composite tube graft, with Bentall's operation in 3, Cabrol's operation in 2, and the modified Bentall's operation in which prosthetic valve was offset inside the tube graft in 4. Early deaths accounted for an operative mortality of 16.7%. The mean aortic cross-clamp time and the amount of bleeding were less with the modified Bentall's operation than with the other composite tube graft procedures. This modification seems to decrease the morbidity and to simplify the procedure in treatment of aneurysm of the ascending aorta with aortic insufficiency. There were 2 late deaths of patients with Marfan's syndrome associated with type I aortic dissection. Regular periodic examinations of the patients is needed, especially when Marfan's syndrome is present, in order to detect and surgically correct residual lesions.

Adult↗
PubMed1990

[A case of complex cardiac anomalies with high pulmonary blood flow treated successfully by PDA banding].

A patient with complex cardiac anomalies who developed severe respiratory insufficiency due to high pulmonary blood flow from a giant PDA was treated successfully by PDA banding. PDA-dependent heart disease causes a reduction in pulmonary blood flow in many patients and is often treated by palliative shunt operation. Although the present patient had PDA-dependent heart disease, heart failure occurred due to increased pulmonary blood flow through PDA and required surgical treatment. We performed PDA banding, because it is technically simple and allows adjustment of the postoperative pulmonary blood flow according to the degree of constriction. The degree of constriction was determined according to the PaO2 value. SO2 levels of 60-70% have been used as an index of the extent of banding, but PaO2 is considered to be equally appropriate.

Constriction↗