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Biomedical subjects

J Y Yu

Publications and source records attributed to J Y Yu.

At least 55 records · Page 3Linked to original sources
PubMed1986

Species variation of gonadotropic activity in an in vitro assay measuring androgen formation by carp (Cyprinus carpio) testis with special reference to bioassay of piscine gonadotropins.

The objectives of this study were to establish a suitable and validated in vitro bioassay of piscine gonadotropins (GTHs) by using a carp testis androgen production system and to compare the androgenic responses in such an assay to gonadotropins from various vertebrate species. The testes from mature carp with gonadosomatic indices of 8-30% were used. Androgen production was first compared with respect to methods for preparation of the carp testis (sliced, minced, homogenized, and collagenase-dispersed testis preparations). The time course of androgen formation, the effects of xanthine and theophylline, and other factors on androgen production also were investigated. Theophylline was more effective than xanthine in potentiation of gonadotropin-evoked androgen formation by carp testis. The testis preparations were incubated in medium 199 (pH 7.40) containing 2 mM theophylline with shaking at 100 cycles/min at 25 degrees C for 4 hr. Homogenized testis preparations had limited ability for androgen production, while sliced, minced, and minced-collagenase-dispersed testis preparations were highly responsive to gonadotropins for androgen production. The minced testis preparation, utilizing 100 mg/ml incubation medium per vial, was chosen as the standard incubation procedure in this study. The minced testis androgen production assay was highly sensitive to gonadotropins from several piscine species (silver carp, common carp, and salmon), and all these GTHs produced parallel dose-related androgen production curves. Mammalian GTHs were also capable of promoting androgen formation by carp testis, but they were much less potent than were piscine GTHs. Pregnant mares' serum gonadotropin (PMSG) was more effective than human chorionic gonadotropin (hCG) in evoking carp testis androgen production.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗
PubMed1986

Effects of long-term testosterone replacement on copulatory activity in old male rats.

Various parameters of copulatory behavior were examined in intact and castrated testosterone-(T-)treated male rats of various ages ranging from 3 to 27 months. Serum T levels were controlled by subcutaneous implantation of different sizes of T-filled Silastic capsules at the time of castration. In intact male rats, scores of various parameters of copulatory behavior declined gradually from middle age and no ejaculation was observed in any rats over 22 months of age. When serum T levels were maintained at 0.78-0.87 ng/ml for 6 months from 4 months of age, these rats showed the same copulatory activity as intact rats, except that fewer rats exhibited ejaculation at 8 and 10 months of age and showed decreased total mount frequency at 10 months of age. Even when serum T levels were maintained at 2.95-3.53 ng/ml for a period of 6 months from 18 months of age, copulatory activity still declined gradually and no rats over 22 months of age ejaculated. However, long-term elevation of serum T level could prevent further decline of intromission frequency in old age. These results indicate that the copulatory activity of male rats in response to circulatory T declined with advancing age and that prolonged low levels of serum T had only a minor role in the onset of decreased responsiveness of neural male sexual behavior.

Aging↗
PubMed1986

Primary neuroendocrine carcinoma of the liver.

A case of primary neuroendocrine carcinoma in an unusual location, the liver, is reported. The neoplasm was composed of small, uniform cells that had distinct borders and grew in strands, ribbons and nests; its appearance resembled that of a carcinoid. Electron microscopy and special staining of the neoplastic cells confirmed the neuroendocrine nature of the tumor, and the cells showed immunoreactivity for gastrin and pancreatic polypeptide by the PAP. The recent literature is reviewed, and the possible histogenesis of hepatic neuroendocrine carcinoma is discussed.

Aged↗
PubMed1986

The influence of estrogen on the hyperglycemic action of alloxan in female rats.

The purposes of this study were to investigate (1) the relationship between estrogen and glucose levels in the circulation during an estrous cycle of the rat and (2) the effect of estrogen on the hyperglycemic action of alloxan. Three-month old Long Evans strain rats were used. The present study established for the first time the correlation between estrogen and glucose levels in the circulation during an estrous cycle. A significant (p less than 0.01) negative correlation was observed with the lowest glucose level at the proestrus stage where estrogen is at peak. The severity of hyperglycemia induced by alloxan was positively correlated with the circulating level of endogenous estrogen, but was negatively correlated with the fasting glucose level. A similar pattern was observed in ovariectomized female rats that were followed by estradiol implantation to achieve a constant level of circulating estrogen. It may be concluded from the present study that estrogen, under physiological conditions, participates in the regulation of glucose metabolism during various stages of the estrous cycle in the rats, and that glucose is likely able to protect the pancreatic beta cells of the animals against the hyperglycemic action of alloxan.

Alloxan↗
PubMed1985

Early detection of hepatocellular carcinoma by real-time ultrasonography. A prospective study.

For early detection of hepatocellular carcinoma (HCC), real-time ultrasonography (US) was performed prospectively in 528 patients, including 236 with cirrhosis, 81 with chronic hepatitis, 168 asymptomatic hepatitis B surface antigen carriers, and 43 with a family history of HCC. Simultaneous measurement of serum alpha-fetoprotein (AFP) level was also done. In addition, 233 patients had regular controls at 3- to 6-month intervals, with an average follow-up period of 1.4 years. On initial screening, a total of 17 patients were found to have HCC: 13 in the cirrhotic group, 3 in the HCC family group, and 1 in the asymptomatic carriers. Of these HCCs, 7 were smaller than 3 cm, 6 were between 3 to 5 cm, and 4 were larger than 5 cm. In patients with tumors smaller than 5 cm, the AFP levels were normal in 46.2%, between 20 to 400 ng/ml in another 46.2%, and only 7.6% were over 400 ng/ml. On follow-up, another seven patients, all in the cirrhotic group, were found to have HCCs varying from 1.6 to 4.7 cm; three of them had normal serum AFP level. The authors conclude that real-time US is more sensitive than AFP assay in early detection of HCC, and the high-risk subjects should receive this procedure at regular intervals.

Adolescent↗
PubMed1985

Effects of septal lesion on lordosis response induced by estradiol in middle-aged and old female rats.

Long-Evans female rats were divided into three age groups: 10 young rats (5 months of age), 7 middle-aged rats (10-13 months of age) and 6 old rats (21-27 months of age). The rats were ovariectomized and immediately implanted subcutaneously with a silastic capsule filled with estradiol benzoate (E2). Lordosis response was compared in each animal before and after the septal lesion. Serum E2 levels were 197 +/- 27 pg/ml (mean +/- SEM), 192 +/- 81 pg/ml and 405 +/- 83 pg/ml in young, middle-aged and old rats respectively. When serum E2 levels were adjusted by analysis of covariance, LQ (lordosis quotient) was 42, 36 and 61 in young, middle-aged and old rats respectively before the septal lesion and 98, 68 and 88 respectively after the septal lesion. The extent of potentiation of lordosis after the septal lesion was less in middle-aged and old rats than young rats. These results indicate that an enhanced lordosis response in aged rats is partly due to high circulating E2 levels and partly due to disinhibition of the septal region on lordosis.

Aging↗
PubMed1984

Ultrasonography of small hepatic tumors using high-resolution linear-array real-time instruments.

Abdominal ultrasonography using a high-resolution linear-array real-time scanner was compared to computed tomography, celiac arteriography, and radionuclide imaging in 24 patients with a total of 33 hepatocellular carcinomas (HCC), 10 patients with cavernous hemangioma (12 tumors), and 2 patients with metastatic carcinoma of the liver (3 tumors), all smaller than 3 cm. Ultrasound proved to be the most sensitive method of detecting such small tumors. Most small HCCs were hypoechoic and most small hemangiomas hyperechoic. Aspiration cytology and/or biopsy under ultrasound guidance detected 92.3% of HCCs and 100% of hemangiomas. Intraoperative ultrasound was employed in 19 cases of small HCC and aided resection in 8. Real-time ultrasound may play a prominent role in early detection and diagnosis of small HCCs.

Adult↗
PubMed1984

Simulatory hypothyroidism pituitary function in vitro: dynamics of TSH release after TRH stimulation in perifused rat hemipituitaries.

The production of immunoreactive TSH by hemipituitaries (Hps) to the stimulation of TRH in perifusion with negligible influence of the feedback of secretogogues and hormones was analysed. The stimulations were of long term continuous (3 hrs) and short term (15 min), with the dose levels of 1, 10 and 100 ng per ml of medium (for 3 hrs) or in 2 ml (for 15 min). The largest amount in production and the fastest rate in release of TSH found in present report is at 10 ng level. Only total TSH, in tissue plus in medium, after continuous TRH stimulation were dose-related, but not in release alone. We present herein an analysis of pituitary TSH production, in a perifusion system under steady TRH stimulation. This arrangement is believed to be a condition simulating hypothyroidism in pituitary level and suitable for study of the functions of the pituitary with hyperactivated thyrotrophs.

Animals↗
PubMed1984

Types of mucosal metaplasia in relation to the histogenesis of gastric carcinoma.

One hundred thirty-nine surgically resected stomachs and 16 stomachs obtained at necropsy in China were studied histochemically to evaluate the types and distribution of mucosal metaplasia in relation to benign and malignant disease. Three classes of mucin were distinguished: small-intestinal (N-acylated sialomucin); colonic (sulfated and O-acylated sialomucin); and gastric (neutral mucin). Small-intestinal type of metaplasia (SIM) occurred in 95% of instances of atrophic gastritis, 36% of cases of superficial gastritis, 60% of cases of gastric ulcers, and 39% of cases of duodenal ulcers. Colonic type of metaplasia (CIM) was less common and was found in only 11% of benign lesions. It was located in the antrum, particularly on the lesser curvature. Mucin was present in 66 of 84 carcinomas. The stomach tumors fell into three histochemical groups: colonic (acid mucin), 32; gastric (neutral mucin), 19; and mixed (acidic and neutral), 15. In 94% (30/32) of colonic type of gastric carcinoma, CIM was present. Thus, CIM is related to development of colonic type of gastric carcinoma, whereas SIM is a nonspecific reaction to mucosal damage.

Adolescent↗
PubMed1983

Endoscopic examination of the upper gastrointestinal tract in infancy.

Forty endoscopic examinations of the upper gastrointestinal tract were performed in 38 infants with an age range from 2 days to 12 months. The main indications were upper gastrointestinal bleeding, chronic intractable vomiting, and small intestinal biopsy. Duodenal ulcer, hemorrhagic gastritis, and gastric erosions were the most common causes of upper gastrointestinal bleeding in infancy. An acute viral infection with fever, aspirin ingestion, and diarrhea frequently preceded gastrointestinal bleeding from duodenal ulcer and gastric erosion. Four of the 27 bleeding patients demonstrated no abnormality endoscopically.

Duodenal Diseases↗
PubMed1983

A placebo-controlled, double-blind study of sucralfate in the short-term treatment of duodenal ulcer.

Seventy-six outpatients with endoscopically proven duodenal ulcer were entered into a double-blind, randomized, placebo-controlled study to assess the efficacy of sucralfate in ulcer healing. The patients were assigned to either sucralfate or placebo given in a dose of 2 tablets of 500 mg 4 times daily. Sixty-five patients were re-evaluated endoscopically at the end of the fourth week of treatment. Complete healing was observed in 24 of the 33 patients (72.7%) on sucralfate and 8 of 32 patients (25.0%) on placebo (Fisher's exact test; p = 0.0003). The improvement of subjective symptoms and the amount of antacid consumed were similar in the two groups. No serious side effects were noted.

Adult↗
PubMed1981

Theory on prospect of population evolution processes.

This paper is aimed at investigating the dynamic process of population growth applied to population of the People's Republic of China. The discrete and continuous models of population evolution process are revised and adjusted to suit the social conditions of China. The relationship between two kinds of models is established. A series of new formulae of demographic indices are studied and defined as functions on the negative space of generalized solutions of the population equation. Based on survey data collected in China for recent years, the prospect of population growth according to different projections is offered for a one-hundred-year period from now on.

Demography↗