Search PubMed⌕ Search

Biomedical subjects

A Leung

Publications and source records attributed to A Leung.

At least 91 records · Page 5Linked to original sources
PubMed1987

The evaluation of a pregnancy test (Tandem ICON) in the management of ectopic pregnancy.

A comparison was made between the Tandem ICON and Gravindex tests in the management of suspected ectopic pregnancy in 38 patients. The Tandem ICON test was significantly more accurate than the Gravindex in predicting an ectopic pregnancy. After the exclusion of cases with intrauterine pregnancy, there was no error when the Tandem ICON test was used, but 8 false negative cases were found with the Gravindex.

Antibodies, Monoclonal↗
PubMed1987

Estrogens, progestogens, and androgens enhance the follicle-stimulating hormone-stimulated plasminogen activator production by cultured rat granulosa cells.

We have previously shown that FSH caused a dose-dependent increase in plasminogen activator (PA) production by cultured rat granulosa cells. PA production was assayed by culturing granulosa cells, obtained from immature diethylstilbestrol-treated rats, on [125I]fibrin plates and determining the extent of fibrinolysis after the addition of the specific substrate plasminogen. To study the effect of ovarian steroids on FSH-stimulated PA production, concomitant treatment with FSH and estradiol [(E2) 10(-7) M], progesterone [(P) 10(-6) M], testosterone [(T) 10(-7) M] or 5 alpha-dihydrotestosterone [(DHT) 10(-7) M] were tested in these cultures. Treatment with E2 significantly enhanced the FSH-stimulated PA production by 35-210% over the whole range of the FSH dose response curve. The augmentation of FSH-stimulated PA production by E2 was not affected by the concomitant treatment with the antiprogestin RU 486 (10(-6) M). Similarly, P significantly enhanced the FSH-stimulated PA production by 34 to 90%. The stimulating action of P on FSH-dependent PA production was blocked by the simultaneous treatment with RU 486. Concomitant treatment with T significantly increased the FSH-induced PA production by 22-60%. That the effect of T was not due to the aromatization to E2 was evidenced by the augmentation by DHT of FSH-stimulated PA production. DHT caused a significant 20-39% enhancement in the responsiveness of the granulosa cells to FSH by further increasing PA production. The enhancement of PA production by androgen is decreased partially by concomitant treatment with the antiandrogen flutamide (10(-5) M) and the antiprogestin RU 486. These in vitro data demonstrated the importance of estrogens, progestogens, and androgens in modulating the stimulating effect of FSH on PA production by immature rat granulosa cells.

Androgens↗
PubMed1987

Serum bioactive follicle-stimulating hormone in men with idiopathic azoospermia and oligospermia.

Using an in vitro granulosa cell aromatase bioassay (GAB), serum bioactive FSH (bio-FSH) levels were measured in 20 fertile men and 74 men with idiopathic azoospermia or oligospermia. The serum bio-FSH levels measured by the GAB assay and the immunoreactive FSH (immuno-FSH) levels measured by RIA were positively correlated (r = 0.93). Compared to normal men, serum bio-FSH and immuno-FSH levels were elevated in patients with idiopathic azoospermia associated with severe germinal epithelium damage; the bioactive to immunoreactive ratio (B:I ratio) of FSH in these men [mean, 1.5 +/- 0.5 (+/- SD)] was significantly lower than that in fertile men (2.7 +/- 0.8). Similarly, in men with moderate and severe oligospermia, the B:I ratios of FSH were decreased (1.4 +/- 0.4 and 1.7 +/- 0.3, respectively). Although serum immuno-FSH levels correlated weakly with mean sperm concentrations in the normal and oligospermic men (r = -0.35), no relationship was found between serum bio-FSH and sperm concentrations. The B:I ratio of FSH correlated weakly with sperm concentration (r = 0.46). These findings suggest that the B:I ratio of FSH measured by the GAB assay decreases in patients with low sperm concentrations and germinal cell failure.

Adult↗
PubMed1987

First branchial cleft fistula: case reports and literature review.

The 1st branchial cleft accounts for about 5% of branchial arch anomalies. The necessity for wide surgical exposure to delineate the anatomy between the facial nerve and tract is stressed; migrating mesenchyme, which brings with it the facial nerve, can orientate medically, laterally or both sides of the tract. Three cases and a literature review are presented.

Branchial Region↗
PubMed1987

Is there a pathogenetic role of hepatitis B virus in lupus nephritis?

In view of the widely disputed frequency with which hepatitis B surface antigen (HBsAg) is found in the sera and kidney biopsy specimens of patients with systemic lupus erythematosus (SLE), serologic screening of HBsAg and immunofluorescence studies for HBsAg and hepatitis B core antigen in renal biopsy specimens were performed in 45 patients with SLE. Five of the 45 patients with SLE had HBs antigenemia, and the prevalence was not significantly different from that of the general population in Hong Kong. The renal biopsy findings of these five patients showed lupus nephritis in two and features suggestive of hepatitis-induced glomerulonephritis in three. Our findings do not support an increased prevalence of HBsAg in sera or kidney of patients with SLE, and hepatitis B virus is unlikely to have a pathogenetic role in SLE in areas where both SLE and HBs antigenemia are common.

Adolescent↗
PubMed1986

LHRH stimulates plasminogen activator and inhibits steroid production by granulosa cells of adult rat Graafian follicles.

We studied the effects of LHRH and its analogs on plasminogen activator production and progesterone and estradiol secretion by granulosa cells isolated from adult rat Graafian follicles. LHRH and its agonist ([des- -Gly10,D-Trp6,Pro9-NHEt]LHRH) stimulated small but significant increases in plasminogen activator production. This stimulatory action of LHRH was blocked by the addition of the specific antagonist ([D- pGlu1,D-Phe2,D-Trp3,6]LHRH). In contrast, LHRH treatment had no significant effect on basal steroid production by granulosa cells of Graafian follicles cultured for 2-6 days. However, LHRH decreased the FSH-stimulated steroidogenesis. This inhibitory effect of LHRH on steroidogenesis was abolished by concomitant addition of the LHRH antagonist. The results show that LHRH has a stimulatory effect on plasminogen activator production and a suppressive action on steroidogenesis in granulosa cells isolated from Graafian follicles of adult rats.

Animals↗
PubMed1985

Suppression of defective-sporulation phenotypes by mutations in the major sigma factor gene (rpoD) of Bacillus subtilis.

Mutations (crsA47 and crsA4) in the major sigma factor gene (rpoD) of Bacillus subtilis RNA polymerase have been found to be powerful intergenic suppressors of spoOB, spoOE, spoOF, spoOK and spoIIG mutations. The crsA47 suppressor restores sporulation of spoOE, spoOF, spoOK and spoIIG mutants to levels near those of wild type bacteria and substantially improves the sporulation of a spoOB strain. The crsA mutations are shown to prevent the induction by aliphatic alcohols of SpoO phenocopies in wild type B. subtilis cells.

Bacillus subtilis↗
PubMed1985

Resolution of prepubertal male gynecomastia following removal of a giant pigmented nevus.

A male infant is reported in whom substantial gynecomastia resolved following removal of a giant pigmented nevus. Endocrinological studies were normal. It is postulated that the nevus contributed to the development of gynecomastia. Surgeons should be aware of a possible relationship between these two seemingly unrelated conditions when making evaluation and management decisions.

Facial Neoplasms↗
PubMed1985

Cross-sectional study of semen parameters in a large group of normal Chinese men.

Testicular size, semen characteristics and serum reproductive hormone levels were studied in 1239 normal Chinese men. The mean testicular size of 17 ml in this group of subjects was similar to other reports in Orientals but was smaller than that reported in Caucasians. Semen volume, and the sperm count, motility and morphology were comparable to those described for Caucasian subjects. The cervical mucus penetration test (Kremer's test) and the zona-free hamster egg penetration test were also studied in some of the subjects. Age showed a positive correlation with the serum levels of FSH and LH, which were highly correlated with each other. Sperm concentration and the total sperm count were positively correlated with testicular volume, the length of abstinence, the % of sperm with an oval head, and the zona-free hamster egg penetration test, but were negatively correlated with serum FSH. Sperm motility was negatively correlated with the duration of abstinence but was positively correlated with the % normal sperm. The results constitute a normal data base from Chinese men for comparison with studies in male infertility and fertility regulation.

Adult↗
PubMed1985

[Nuclear spin resonance tomography and its anatomic-pathological correlates].

NMR examination of a preserved head was performed using different Inversion Recovery and Spin Echo sequences. Correlations were made between the MR and the macroscopic pathological and later, the histological appearances of the specimen at corresponding slices. Normal anatomical structures and the multiple pathological lesions were all clearly demonstrated by MRI.

Aged↗