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Biomedical subjects

G Watanabe

Publications and source records attributed to G Watanabe.

At least 325 records · Page 18Linked to original sources
PubMed1989

In vivo release of luteinizing hormone releasing hormone increases with puberty in the female rhesus monkey.

To determine the regulatory mechanism of the LHRH release associated with puberty, episodic release of LHRH from the stalk-median eminence was measured using a push-pull perfusion technique in conscious prepubertal and peripubertal female monkeys. After insertion of a push-pull cannula into the stalk-median eminence, a modified Krebs-Ringer phosphate buffer solution was infused through the push-cannula, and perfusates were collected through the pull-cannula at 200 microliters/10 min. LHRH in perfusates was determined by RIA. Two 6-h sampling sessions, in the morning (0600-1200 h; lights on 0600 h) and in the evening (1800-2400 h; lights off 1800 h) were performed in each animal. LHRH release patterns were analyzed in prepubertal (15.7 +/- 0.7 months of age; mean +/- SEM, n = 6) early pubertal (premenarcheal; 26.1 +/- 1.0 months, n = 7), and midpubertal (40.0 +/- 1.4 months, n = 6) monkeys. Results were as follows: 1) LHRH release was pulsatile in all age groups. While LHRH release in five of six prepubertal animals consisted of small (amplitude less than 2.5 pg/ml) pulses, in all peripubertal animals LHRH release was a mixture of small and large (amplitude greater than 2.5 pg/ml) pulses. 2) There was a significant developmental increase in mean LHRH release (P less than 0.02), and this was particularly apparent in the evening. Mean LHRH release in the early and midpubertal groups was higher than that in the prepubertal group (P less than 0.05 for morning and P less than 0.01 for evening). The mean release in the evening of the midpubertal group further increased over that of the early pubertal group (P less than 0.05). 3) Similarly, LHRH pulse amplitude increased developmentally (P less than 0.01). Pulse amplitudes in early and midpubertal groups were higher than those in the prepubertal group (P less than 0.05 for morning and P less than 0.02 for evening). Again the amplitude in the evening further increased from the early pubertal to the midpubertal period (P less than 0.05). 4) There was also a developmental increase in basal LHRH release (P less than 0.01). The evening values in the early pubertal and midpubertal groups were higher than those in the prepubertal group (P less than 0.05). 5) The interpulse interval decreased developmentally (P less than 0.001). Interpulse intervals in early and midpubertal groups were shorter than those in the prepubertal group (P less than 0.01 for morning and P less than 0.025 for evening).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Peripheral blood levels of immunoreactive inhibin during pseudopregnancy, pregnancy and lactation in the rat.

Concentrations of inhibin in peripheral blood were determined by radioimmunoassay in pseudopregnant, pregnant and lactating rats and correlated with the status of follicular development, luteal function in the ovaries and placental function. In pseudopregnant rats, plasma concentrations of inhibin remained relatively high from days 2 to 12 of pseudopregnancy and no significant changes occurred throughout pseudopregnancy. In pregnant rats, a marked decline in plasma concentrations of inhibin occurred between days 6 and 14 followed by an abrupt increase on days 20 and 21. In lactating rats, plasma concentrations of inhibin were consistently lower in dams nursing eight pups than in dams nursing two pups. Plasma concentrations of inhibin remained low during the early stages of lactation followed by a significant increase during the late stages in dams nursing eight pups. These changes in inhibin during the period of lactation correlated with those of plasma concentrations of LH, but not with those of oestradiol-17 beta, testosterone and progesterone. Throughout pseudopregnancy, pregnancy and lactation, on the other hand, plasma concentrations of FSH were within the range of dioestrous levels. These findings indicate that concentrations of inhibin in peripheral plasma vary with the number of healthy antral follicles and no positive correlation was observed with luteal function during the luteal phase in rats. The results also suggest that inhibin is a more direct index of follicular development than oestradiol-17 beta in rats.

Animals↗
PubMed1989

Radioimmunoassay of inhibin in various mammals.

A sensitive radioimmunoassay (RIA) for the determination of inhibin in peripheral plasma and tissue homogenates of different species has been developed using antisera to partially purified bovine follicular fluid (bFF) inhibin and 125I-labelled bFF 32 kDa inhibin. Antisera were produced by immunization of rabbits with partially purified bFF inhibin prepared by immunoaffinity chromatography. Increasing doses of a high titre antiserum could neutralize the suppressing effect of bFF, porcine follicular fluid and rat ovarian homogenate on FSH secretion from rat anterior pituitary cells in culture. Sensitivity of the assay was 3.1 ng International Research Standard of porcine inhibin per tube. Parallel inhibition curves were obtained for inhibin preparations from female and male animals of ten species, i.e. cattle, goats, sheep, cats, dogs, monkeys, pigs, horses, rats and man. Inhibin subunits and related proteins cross-reacted minimally with the antiserum used in the study. Plasma concentrations of inhibin in adult male and female rats were measured by the RIA before and at various times after gonadectomy. Inhibin levels in peripheral plasma before gonadectomy were significantly higher in adult female than in adult male rats. Inhibin levels decreased abruptly after gonadectomy in both sexes and they correlated negatively with plasma concentrations of FSH. This inhibin RIA will facilitate studies of the physiology of inhibin in various species of animals.

Animals↗
PubMed1989

Sudden unexpected death from a superior mesenteric venous thrombosis after a gastrectomy.

Reported are the autopsy findings of a 55-year-old man who died unexpectedly 20 h after a subtotal gastrectomy of an early gastric cancer. The cause of his death was a superior mesenteric venous thrombosis, involving his small bowel which manifested a marked vascular engorgement. The entire small bowel mesentery was thickened and edematous, and hemorrhagic infarctions were scattered near the bowel. Many fresh thrombi could be identified in the superior mesenteric veins. This case is described, together with the legal aspects of medical malpractice.

Death, Sudden↗
PubMed1989

[Evaluation of the collo-thoraco-abdominal dissection for the intrathoracic esophageal carcinoma].

Five hundred and forty three cases of intrathoracic esophageal carcinoma were reviewed. Of these, one hundred and sixty one cases had collo-thoraco-abdominal (CTA) dissection and three hundred and eighty two cases had thoraco-abdominal (TA) dissection. Postoperative pulmonary complications occurred in 35.5% of the patients who had CTA dissection and in 18.0% of those who had TA dissection. Incidences of postoperative hoarseness of voice and anastomotic leakage were almost similar in the two groups. However, the mortality rates within 30 postoperative days was 4.3% for the CTA groups compared to 1.8% for the TA group. The average number of lymph nodes resected per case was much higher in the CTA group than than the TA group. This implied that the dissection was more extensively performed in the CTA group involving not only bilateral cervical regions but also the upper mediastinum continuing into the neck. Better 1, 2 and 3 years survival rates were observed in the CTA group than the TA group, but for the 4, 5 years survival rates there was no statistical difference noted. For stage-0 and stage-4 carcinoma of the upper third esophagus, marked improvement in the survival rates were obtained in the CTA dissection cases. In conclusion, collo-thoraco-abdominal dissection can be justified for the surgical treatment of intrathoracic esophageal carcinoma despite its postoperative mortality rate of 4.3%.

Abdomen↗
PubMed1989

[Second surgical intervention for contralateral recurrence or second primary lung cancer].

Resection of contralateral lung cancer (6 cases of pulmonary metastasis from the first lung cancer and one case of second primary lung cancer) were evaluated retrospectively in terms of postoperative complication, pulmonary function and survival rate. Out of 691 cases with resected non small cell lung cancer, 7 cases (1.0%) had contralateral lung cancer which were resected as the second operation. Six cases were squamous cell carcinoma and one case was adenocarcinoma. The interval between the first and the second operation was 12 months to 10 years (average 46 months). The post-operative stage of first lung cancer were stage I in 5 cases and stage IIIB in 2 cases, but no case had lymphadenopathy at the first operation. Operative procedures for contralateral lung were as follows; one case of lobectomy----lobectomy, one case of lobectomy----segmentectomy, two cases of lobectomy----partial resection, two cases of pneumonectomy----partial resection. For a metachronous lung cancer, right upper sleeve lobectomy was done as the first operation followed by left lower sleeve lobectomy as the second cancer five years later. Contralateral lung resection impaired pulmonary function, but all cases well tolerated the second operation. The five-years survival rate after second operation was 40.0%.

Aged↗
PubMed1989

[Left ventricular performance before and after left ventriculotomy and removal of a left ventricular aneurysm].

The effects of left ventriculotomy on left ventricular performance were studied in seven patients with ventricular tachyarrhythmia (VT) and nine patients with left ventricular aneurysm (LVA). Hemodynamic and left ventriculographic findings were evaluated before and after operations. In VT the non-contracting areas, measured at end-diastole, as mean 10.8 +/- 7.1% of the left ventricular internal surface area. There was no significant fall in left ventricular ejection fractions (EF), cardiac indexes (CI) and left ventricular end-diastolic volume indexes (LVEDVI) after left ventriculotomy. In LVA, the non-contracting areas decreased from 31.0 +/- 7.4% to 13.7 +/- 13.5% (p less than 0.01) in association with a reflex decrease in LVEDVI from 117 +/- 31.8 ml/m2 to 90.4 +/- 24.7 ml/m2 (p less than 0.05). EF increased from 40.8 +/- 7.00% to 54.6 +/- 10.7% (p less than 0.01). There was no significant change in CI and left ventricular stroke volume index after left ventricular aneurysmectomy. The observations indicate that left ventriculotomy of limited size is an acceptable and a safety approach to the ventricular tachyarrhythmias and another cardiac operations.

Adolescent↗
PubMed1989

[Surgical management of infective endocarditis].

We reviewed fourty-six patients who had undergone surgery for infective endocarditis in the past fifteen years and identified risk factors affecting the outcome. Twenty-nine patients had infection of the native valve only, 11 had infective endocarditis associated with congenital heart disease, and 6 had prosthetic valve endocarditis. Overall hospital mortality was 6.5%. Prosthetic valve endocarditis carried a higher mortality (33%) than native valve endocarditis (3.4% or congenital heart disease with infective endocarditis (0%). For the patients with active endocarditis, the early mortality rate was higher (13%) than with inactive endocarditis (3.2%). Staphylococcal infections were more likely to cause severe valve destruction and residual infection than streptococcal infection. Our results indicated that surgical management of infective endocarditis should be done after the completion of adequate antibiotic therapy. Early diagnosis should reduce the mortality, prevent fatal complications, and lead to qualitative improvement of infective endocarditis.

Adolescent↗
PubMed1989

[Skeletal muscle ventricle used for right ventricle assistance].

There are a number of advantages in using an electrically stimulated autogenous skeletal muscle to construct an auxiliary ventricle to assist a heart. The purpose of this study was to determine the feasibility of biological right ventricular assistance using long-term electrically stimulated skeletal muscle grafts. In fourteen dogs, the latissimus dorsi muscles and the right thoracodorsal nerves were exposed and unipolar pulse generator was implanted. The initial rate of 70 cycle/min. was increased to a rate of 100 cycle/min. Six or 12 months later, the latissimus dorsi was wrapped around a latex pouch equipped with inflow and outflow valved conduit (skeletal muscle ventricles; SMVs). The SMVs were connected to main pulmonary artery and right atrium. These SMVs were stimulated 20 Hz for 200 msec at a fixed rate of 90 cycle/min, the hemodynamic changes with or without skeletal muscle ventricular assistance (SMVA) were measured. In as animals the circulation failed after total right ventricular bypass without SMVA. But the SMVA increased aortic blood pressure, aortic blood flow, left atrial pressure and peak pulmonary pressure significantly. There was a linear correlation between central venous pressure and skeletal muscle ventricular assist flow. Histologic studies showed the conditioned muscles had a greater percentage of slow-twitch, fatigue resistant fibers on ATPase stain. These results suggested the long-term electrical conditioning skeletal muscle could be possible to use SMVs in humans to provide support in children with some types of congenital heart disease.

Animals↗
PubMed1988

Intraoperative evaluation of coronary bypass grafts by measuring myocardial blood flow using the electrolytic hydrogen clearance method.

The regional myocardial blood flow (MBF) was measured in 33 patients who underwent coronary bypass graft surgery in order to evaluate the efficiency of coronary bypass grafts in restoring MBF. MBF was measured by the electrolytic hydrogen clearance method during the coronary bypass surgery. The mean prebypass MBF was 161 +/- 19, 162 +/- 12, 80 +/- 12, 43 +/- 14, 104 +/- 18 ml/min/100 g in segments supplied by the left anterior descending coronary artery (LAD) showing less than or equal to 50 per cent, 75 per cent, 90 per cent, 99 per cent, and 100 per cent stenosis with collaterals, respectively. After bypass grafting of the LAD, the mean MBF increased from 70 +/- 13 and 126 +/- 12 ml/min/100 g to 133 +/- 14 and 163 +/- 9 ml/min/100 g in the segments with and without infarction, respectively. The mean postbypass MBF was 149 +/- 10 and 152 +/- 14 ml/min/100 g in the segments supplied by the LAD bypassed with saphenous vein grafts and mammary artery grafts, respectively. Postbypass MBF was dependent upon the magnitude of myocardial infarction. Measurement of MBF by the electrolytic hydrogen clearance method made it possible to quantitatively evaluate myocardial perfusion at the time of operation. It also provided direct information about the effectiveness of myocardial revascularization.

Blood Flow Velocity↗
PubMed1988

A new male pseudohermaphrodite rat mutant with androgen deficiency.

A male pseudohermaphrodite rat mutant showing a blind-ending vagina, small undescended testes, rudimentary male sex accessory organs and XY karyotype was investigated. Genetic analysis revealed an autosomal single recessive transmission of this defect and indicated that the gene action is restricted to males. Microscopic examination showed an absence of typical Leydig cells in testes of the mutant. Plasma concentrations of testosterone were extremely low and the values were comparable to those of castrated male rats and did not change after castration and/or after administration of hCG. Plasma concentrations of LH and FSH were remarkably high and the values were comparable to those of long-term castrated normal male rats which declined to basal levels after administration of exogenous testosterone. Weights of thymus and adrenal glands decreased and weights of preputial glands, kidneys and male accessory sex organs increased in response to exogenous testosterone. These results indicate that the primary defect in the mutant is an androgen deficiency probably due to a Leydig cell agenesis in the testes.

Androgens↗
PubMed1988

A scanning electron microscopy and electron probe X-ray microanalysis (SEM-EPMA) of pink teeth.

Samples of postmortem pink teeth were investigated by scanning electron microscopy and electron probe X-ray microanalysis. Fracture surfaces of the dentin in pink teeth were noticeably rough and revealed many more smaller dentinal tubules than those of the control white teeth. Electron probe X-ray microanalysis showed that the pink teeth contained iron which seemed to be derived from blood hemoglobin. The present study confirms that under the same circumstance red coloration of teeth may occur more easily in the teeth in which the dentin is less compact and contains more dentinal tubules.

Animals↗
PubMed1988

[Intraoperative ultrasound imaging and its application to cardiovascular operations].

Intraoperative ultrasound imaging was employed for qualitative and quantitative studies during cardiovascular operations in 36 patients. A 7.5M Hz high frequency ultrasound scanner was used to image. The ultrasound probe was sterilized by gas and placed directly on the heart by the hand of surgeon. On the clinical application, 10 cases of patients with coronary artery disease were scanned. Left main trunk and proximal portion of other three branches were visualized and pathological lesions were demonstrated clearly. Four cases of myocardial bridging were observed. Intramyocardial coronary arteries were easily detected and supraarterial myotomy was performed safely. Four cases of valvular disease were examined. We could evaluate valvular anatomy and physiologic aspects of valvular disease and 15 cases of aortic root disease were examined intraoperatively. In aortic root dissection, the size and site of the true and false lumens were clearly demonstrated in all patients. In conclusion intraoperative ultra-sound imaging is a versatile technique with quantitative and qualitative studies of cardiovascular surgery during operation and the perioperative period.

Aortic Dissection↗