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Biomedical subjects

G Watanabe

Publications and source records attributed to G Watanabe.

At least 379 records · Page 21Linked to original sources
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Inhibins in the male Göttingen miniature pig: Leydig cells are the predominant source of inhibin B.

The expression of inhibin subunits in the testes of the Göttingen miniature pig was examined by in situ hybridization and immunohistochemistry. In addition, the major forms were determined by enzyme-linked immunosorbent assay (ELISA). Strong positive immunostaining for the inhibin alpha subunit was observed in Sertoli and late-stage germ cells, but it was weak in Leydig cells. However, Leydig cells showed strong positive staining for the betaA subunit, but Sertoli cells and spermatogonia showed a weak reaction. Strong positive immunostaining for the betaB subunit was observed in Leydig cells but spermatogonia showed weak staining for it. In contrast to the staining specificity of inhibin alpha and betaA subunits, the betaB subunit did not exhibit positive staining in Sertoli cells. In situ hybridization revealed that although the a subunit mRNA signal was highly expressed in all cell types, the reaction appeared to be stronger in Sertoli cells and spermatogonia than in Leydig cells. betaA subunit mRNA expression was somewhat identical to that of the alpha subunit, however, germ cells showed a weak stain for it. A strong, positive mRNA signal for the betaB subunit was confined to Leydig cells and late-stage germ cells. ELISA results showed that concentrations of inhibin B and inhibin pro-alphaC were high in the circulation and testes. In contrast, inhibin A levels in both plasma and testes were undetectable. The present results strongly suggest that inhibin B is the major form of circulating inhibin and that Leydig cells are the predominant source of this dimeric inhibin in male Göttingen miniature pigs. Furthermore, the germ cells also appear to be an important source of circulating inhibins.

Animals↗
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Two small intrahepatic cholangiocarcinomas with different sonographic appearances.

We report on 2 cases of small intrahepatic (or peripheral) cholangiocarcinomas initially detected by sonography and completely resected. The lesions had a peripheral hypoechoic component and a central isoechoic or hyperechoic component. One had posterior acoustic shadowing on sonography, and the other did not. Comparison with pathologic findings in both cases indicated that severe fibrotic changes may have caused the posterior acoustic shadowing. This finding is extremely rare. We found only 1 previously reported case of cholangiocarcinoma accompanied by acoustic shadowing.

Acoustics↗
PubMedDate not supplied

Ultrasonically guided cholangiography and bile drainage.

Ultrasonically guided percutaneous transhepatic cholangiography (UG-PTC), bile drainage (UG-PTBD) and gallbladder drainage procedure (UG-PTGBD), developed by us, were performed in 47, 183 and 36 patients, respectively. In 47 patients UG-PTC was successfully performed 51 times without complications. By UG-PTBD 220 intubations were carried out successfully and four attempts failed (1.8%). The main complication was that the catheter slipped out from the bile duct. It was experienced 27 times (12.3%) in 23 patients (12.4%) from two to 47 days after intubation. UG-PTGBD was successfully performed 36 times. Bleeding from the catheter was experienced in four patients. However, other complications such as cholascos were not experienced. Due to the development of ultrasonic diagnosis and the UG-PTBD procedure, the indications for percutaneous transhepatic cholangiography (PTC) are now limited. For differentiation of jaundice, ultrasonic examination takes over from PTC. For preparation of PTBD, thin needle cholangiography is no longer necessary because UG-PTBD is a single-step procedure without the need for cholangiography. Therefore, the indication for PTC is limited to patients with partial dilatation of intrahepatic bile ducts without jaundice, for example when only the left hepatic duct is dilated due to hepatolithiasis.

Bile↗
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Hypothyroidism increases prolactin secretion and decreases the intromission threshold for induction of pseudopregnancy in adult female rats.

In order to understand the mechanism by which thyroid hormones alter prolactin (PRL) secretion, we investigated the role of tuberoinfundibular dopamine (TIDA) neurons and pituitary and hypothalamus vasoactive intestinal peptide (VIP) in thiouracil- (0. 03% in drinking water for 16 days) induced-hypothyroid adult female rats. The intromission threshold for induction of pseudopregnancy also was examined to evaluate the PRL response to coital stimulation in hypothyroid rats. Hypothyroidism in adult female rats did not affect TIDA neuronal activity as measured by tyrosine hydroxylase activity (DOPA accumulation 30 min after administration of m-hydroxybenzylhydrazine dihydrochloride, 100 mg/kg, i.p.) in the stalk-median eminence compared with that in euthyroid rats, whereas pituitary concentration of VIP was dramatically increased. Plasma concentration of PRL was higher at 1100 h of proestrus and estrus in hypothyroid rats as compared with that of euthyroid rats. The proportion of female rats exhibiting pseudopregnancy was higher in hypothyroid animals (100%) receiving seven intromissions than in euthyroid animals (43%). Administration of L-thyroxine in hypothyroid rats decreased the proportion of pseudopregnancy (40%) to the level of euthyroid animals. These results indicate that the increased level of pituitary VIP probably affects PRL secretion in a paracrine or autocrine manner and account for the hyperprolactinemia induced in hypothyroid female rats. No role for TIDA neurons in PRL elevation can be ascribed. A decrease in the intromission threshold for induction of pseudopregnancy might be due to increased levels of PRL in hypothyroid female rats.

Animals↗
PubMedDate not supplied

A dose-response relationship between chromosome aberrations and hypoxic insults in overripened hamster ova.

An attempt was made to analyze the quantitative occurrence of chromosome anomalies by the exposure of slightly overripened ova (delayed fertilization) to hypoxic insults in golden hamsters. Three groups were established: (1) a control group (PO2 = 152 mmHg); (2) a 4,500 m altitude group (PO2 = 87 m5 hr post-ovulatory aging revealed no striking effect on reproductive performance, as well as on the production of chromosome aberrations. Nervertheless, even in a slightly overripened condition ovum increased in susceptibility to the production of chromosome anomalies after hypoxic exposure equivalent to 4,500 m altitude. The dose-response relationship between hypoxia and the occurrence of triploidies was particularly distinguished. On the other hand, a similar relationship was not so evident in the production of aneuploidies, especially of trisomies. It can, therefore, be surmised that the change in the cytogenetic milieu at the time of the second polar body extrusion has some quantitative relation to the severity of environmental stressors.

Animals↗
PubMedDate not supplied

Trisomies and triploidies in hamster embryos: induction by low-pressure hypoxia and pH imbalances.

The authors produced trisomic and triploid embryos by mating hamster females approximately 1 hr before estimated ovulation and subsequently submitting them to low-pressure atmospheres equivalent to those found at mountain altitudes for 6 hr. During hypoxic exposures in the low-pressure chamber, the continuous monitoring of pH levels--both subcutaneously and intramuscularly--registered pH decreases from inital values as high as 7.6 to below 6.9. These findings indicate that trisomies in some embryos and triploidies in others have their origin in different, but related mechanisms involving maternal pH imbalances between ovulation and fertilization.

Acid-Base Imbalance↗
PubMedDate not supplied

Diagnostic value of plasma vascular endothelial growth factor as a tumor marker in patients with non-small cell lung cancer.

We assessed the diagnostic value of circulating VEGF as a tumor marker in patients with lung cancer and compared its clinical utility with that of other markers such as carcinoembryonic antigen (CEA) and cytokeratin 19 (CYFRA). One hundred and sixty non-small cell lung cancer patients and 70 healthy volunteers were included in the study. Circulating VEGF was assessed by enzyme-linked immunosorbent assay (ELISA). The serum concentrations of both CEA and CYFRA were measured by means of immunoradiometric assays. The diagnostic value of plasma VEGF (VEGFp) was better than that of CYFRA and similar to that of CEA. When the diagnostic value of VEGFp and CEA for the diagnosis of adenocarcinoma was compared, the two markers proved to have nearly equal discriminatory power. In diagnosing squamous cell carcinoma, VEGFp showed less discrimination than CYFRA. When the diagnostic value of VEGFp was analyzed for stage I adenocarcinoma patients, VEGFp was slightly more discriminatory than CEA. The combination assay of VEGFp and CEA had a sensitivity of 75% and a specificity of 60% at a cutoff of 104.4 pg/mL for VEGFp and 5.2 ng/mL for CEA. The combination of VEGF and CEA was superior to CEA alone in the early diagnosis of adenocarcinoma of the lung.

Adult↗