Roles of Gonadotropin Receptors in Sexual Development of Medaka.

The gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are secreted from the pituitary and bind to the FSH receptor (FSHR) and LH receptor (LHR) to regulate gonadal development in vertebrates. Previously, using fshr-knockout (KO) medaka (Oryzias latipes), we demonstrated that FSH regulates ovarian development by elevating estrogen levels. However, the lhr-KO phenotype in medaka is poorly characterized. Here, we generated lhr-KO medaka using the transcription activator-like effector nuclease (TALEN) technique. We analyzed its phenotype and that of fshr-KO, lhr;fshr double-heterozygotes (double-hetero), and double-KO fish. All genetically male medaka displayed normal testes and were fertile, whereas fshr-KO and double-KO genetically female fish displayed small ovaries containing many early pre-vitellogenic oocytes and were infertile. Although lhr-KO genetically female fish had normal ovaries with full-grown oocytes, ovulation did not occur. Levels of 17α,20ß-dihydroxy-4-pregnen-3-one, which is required for meiotic maturation of oocytes and sperm maturation in teleost fish, were significantly decreased in all KO female medaka ovaries except for double-heteros. Further, 17ß-estradiol levels in fshr-KO and double-KO ovaries were significantly lower than those in double-heteros. These findings indicate that LH is necessary for oocyte maturation and FSH is necessary for follicle development, but that neither are essential for spermatogenesis in medaka.

[A case of delayed diagnosis of pulmonary thromboembolism in a patient with mitral stenosis undergoing cesarean section].

Cesarean section was performed under general anesthesia in a 38-year-old patient with congestive heart failure due to severe mitral stenosis. During surgery, pulmonary hypertension, right ventricular distension and the dissociation of PETCO2 and PaCO2 were observed. However, pulmonary thromboembolism (PTE) was proved after the operation when she developed severe hypotension in the intensive care unit. Although she recovered once from circulatory unstability with the use of percutaneous cardiopulmonary support (PCPS) and she could be weaned from PCPS at the 4th postoperative day, she died from tracheal bleeding and recurrent cardiopulmonary collapse 22nd day after the surgery. It should be noted that the increasing dissociation of PETCO2 and PaCO2 may be an early sign of PTE even in a patient with severe mitral stenosis and pulmonary hypertension.

[Perioperative cardiovascular complications in patients with hypertrophic cardiomyopathy].

BACKGROUND: The aim of this study was to examine the incidence of cardiac complications in patients with hypertrophic cardiomyopathy (HCM) during noncardiac surgery. METHODS: A retrospective study was made for surgical patients in the period of 1989-2000 at Kitasato University Hospital. RESULTS: Thirty out of 66000 patients were preoperatively diagnosed as HCM. Sixty percent of the HCM patients had one or more perioperative cardiovascular complications. There were perioperative congestive heart failure in 3 patients (10%), and myocardial ischemia in 4 patients (13%). However, there were no myocardial infarction, no life-threatening dysarrthythmia and no cardiac death. Factors which appeared to be associated with the perioperative cardiovascular complications were the type of HCM (HOCM), major surgery, general anesthesia and preoperative medication with a beta-blocker or a calcium channel blocker. CONCLUSIONS: It is suggested that patients with HCM undergoing noncardiac surgery have a high incidence of cardiac complications such as congestive heart failure and myocardial ischemia.

[Clinical characteristics of perioperative pulmonary thromboembolism: analysis of 18 patients in Kitasato University Hospital].

Clinical characteristics of perioperative pulmonary thromboembolism (PTE) at Kitasato University Hospital in Japan were analyzed. Eighteen patients were documented as apparent diagnosis of PTE which developed perioperatively in the period of 1991-1999. The incidence of PTE was 18 out of approximately 50,000 surgical cases. Mean age of patients was 48 years (range, 21 to 79 years). There were 4 men and 14 women. Perioperative risk factors included obesity with body mass index over 26.4 (6/18), and prolonged bed rest after surgery more than 4 days (6/18). Perioperative PTE tended to occur in patients with laparoscopic cholecystectomy (3/18) and cesarean section (3/18). Seven out of 18 PTE patients died. It should be noted that perioperative PTE is prevalent in patients with risk factors of obesity and prolonged bed rest after surgery, and that laparoscopic cholecystectomy and cesarean section may become additional risk factors in patients who are otherwise healthy young adults.