Biomedical subjects

T S Yang

Publications and source records attributed to T S Yang.

At least 55 records · Page 3Linked to original sources

PubMed1995

Comparison of human menopausal gonadotropin and follicle-stimulating hormone with gonadotropin-releasing hormone agonist desensitization for controlled ovarian hyperstimulation in in vitro fertilization.

BACKGROUND: A pregnancy in patients treated with gonadotropin-releasing hormone agonists (GnRHa) using follicle-stimulating hormone (FSH) alone was first reported by Shaw et al. in 1991. Recently, several comparative trials have shown that FSH is as effective as human menopausal gonadotropin (hMG) in this indication. In other words, the residual endogenous levels of luteinizing hormone (LH) in GnRHa treated cycles may be generally sufficient to support FSH-induced follicular development to exempt from the co-administration of exogenous LH. METHODS: A total of 42 consecutive candidates for in vitro fertilization (IVF) participated in a prospective randomized study. In this study, the efficacy of two different gonadotropins (Pergonal and Metrodin, Serono, Italy) in inducing ovulation was investigated. All treated women were less than 40 years of age and had received a long desensitized protocol by a GnRHa (Leuprolide acetate, Takeda or Decapeptyl, Ferring). Ovarian inactivity was monitored by plasma estradiol and LH concentration. After the pituitary gland was down-regulated, all patients were given either hMG (n = 25) or FSH (n = 17) for controlled ovarian hyperstimulation (COH). RESULTS: The mean number of gonadotropin ampoules and the peak estradiol level were significantly higher in hMG group than in the FSH group. No significant differences were found between both groups in the incidence of cancelled cycles, failed oocyte recovery, mean number of oocytes recovered per patient, the fertilization and embryo cleavage-rate. However, the hMG group demonstrated a higher pregnancy and abortion rate. CONCLUSIONS: There is no significant difference between hMG and FSH stimulation when used following GnRHa desensitization for COH, so the cost should be considered.

Adult↗

PubMed1995

Efficacy and safety of estriol replacement therapy for climacteric women.

BACKGROUND: As an estrogen derivative, estriol is rather effective in the relief of climacteric symptoms due to estrogen deficiency. When given one dose a day, it will not provoke endometrial proliferation and shedding. Thus, it is suitable for postmenopausal women who no longer want to have uterine bleeding and for those with comparatively higher risk of endometrial hyperplasia. In the aspect of postmenopausal osteoporosis, the prevention of further bone loss due to estrogen deficiency is also important and to be evaluated. METHODS: We collected 20 patients, aged 44-62 years, who had undergone either natural or surgical menopause and were treated with estriol succinate (Synapause; Organon; Holland 2 mg/tab) 2 mg/day for 2 years, with relief of climacteric symptoms evaluated after the first 3 months of treatment. Bone mineral density (BMD) of lumbar spine was measured using quantitative computed tomography (QCT) after one and two years of treatment, respectively. RESULTS: Estriol was very effective in the improvement of major subjective climacteric complaints in 86% of patients, especially hot flush and insomnia within 3 months. The atrophic genital changes caused by estrogen deficiency were also improved satisfactorily. No subjective symptoms induced by the therapy were seen. The rate of uterine bleeding was low, complained by only one patient. However, our study did not show the preventive effect of estriol against osteoporosis. CONCLUSIONS: Estriol can be a safe and effective alternative in the relief of climacteric symptoms for postmenopausal women, but it cannot prevent the bone loss.

Adult↗

PubMed1994

Some physicochemical and enzymic properties of selenium-containing abzyme.

We successfully prepared the Se-containing abzyme (Se-abzyme) with glutathione peroxidase (GPX) activity and further studied its physicochemical and enzymic properties and stabilities. Data showed that the isoelectric point of the abzyme was 6.95-7.08, and its molecular weight was 158 KD. The ranges of optimum pH and temperature of the Se-abzyme were wider than the native GPX. The store stability of the abzyme was higher than the native GPX. The Se content in the abzyme was found to be 5 mol Se/mol abzyme by X-ray photoelectron spectrum, and binding constant 1.11 x 10(7)M-1 by using ELISA method. The Se-abzyme was inhibited competitively by dithiobis(2-nitrobenzoic acid) (DTNB), and inhibition constant was determined to be 1.25 x 10(-3)M-1.

Electrophoresis, Polyacrylamide Gel↗

PubMed1994

Generation of selenium-containing abzyme by using chemical mutation.

A new strategy for generating abzyme was developed. Glutathione peroxidase (GPX, EC 1.11.1.9) is one of the important members of antioxidation enzyme system; it catalyzes the reductions of a variety of hydroperoxides in presence of glutathione(GSH). We have first prepared the monoclonal antibody (McAb) with GSH binding sites, then incorporated GPX catalytic group selenocystein (SeCys) into the antibody combining sites by using chemical mutation. Thus the mutated antibody displays high GPX activity, which approaches the magnitude level of native GPX, exhibits the kinetic behavior similar to native GPX, and has some advantages over native GPX.

Animals↗

PubMed1994

Transient neurological disturbances induced by the chemotherapy of high-dose methotrexate for osteogenic sarcoma.

Temporary neurologic abnormalities were observed in one out of 23 patients undergoing chemotherapy with high-dose methotrexate (HD-MTX) for osteogenic sarcoma. This patient developed sequential symptoms including alternative hemiparesis, dysarthria and altered consciousness 5 days after the second course of HD-MTX (8 gm/m2 by 6 h continuous infusion) with leucovorin rescue. Laboratory evaluations disclosed normal electrolytes, hemograms and non-toxic serum MTX levels at the onset of the symptoms. Computed tomography of the brain was normal but electroencephalography showed focal theta and delta slow waves over the right temporal-parietal-occipital area. The neurological symptoms resolved completely within 72 h.

Adolescent↗

PubMed1994

[Effect of concanavalin A on morphology and DNA synthesis of resting chondrocyte cultures].

Rabbit chondrocytes were isolated from resting cartilage of ribs of 4-week-old New Zealand rabbits. Chondrocytes were seeded at low density and grown to confluency in medium (DME) with 10% fetal bovine serum, 50 micrograms/ml ascorbic acid, and antibiotics, at 37 degrees C under 5% CO2 in air, and then serum concentration was reduced to 0.3%. At the low serum concentration, chondrocytes adopted fibroblastic morphology. Addition of concanavalin A to the culture medium induced a morphologic alteration of the fibroblastic cells to polygonal or spherical chondrocytes that were surrounded by refractile matrix. Wheat germ agglutinin and garden pea lectin induced similar cell shape changes without any increase in matrix synthesis. Concanavalin A decreased [3H]thymidine incorporation into DNA in a dose-dependent manner with an ED50 of 0.4-1 micrograms/ml in the presence of various concentrations of serum ranging from 0.3 to 20%. The concanavalin A inhibition of DNA synthesis was abolished by 10 mmol/L methyl-D-mannopyranoside. The inhibition of chondrocyte proliferation does not seem to be specific to concanavalin A. Wheat germ agglutinin, lentil lectin, phytohemagglutinin, Ulex europeaus agglutinin, and garden pea lectin also decreased, dose-dependently, [3H]thymidine incorporation into DNA in chondrocytes. Other lectins at 0.01-20 micrograms/ml had little effect on [3H] thymidine incorporation. Because the molecular structure of concanavalin A and its mode of actions have been extensively characterized, chondrocytes exposed to this lectin will be useful as a novel model in studying of the control of cellular differentiation.

Animals↗

PubMed1994

[Stimulation of maturing and terminal differentiation by concanavalin A in rabbit permanent chondrocyte cultures].

The effect of concanavalin A (Con A) on maturing and terminal differentiation in permanent chondrocyte cultures were examined. Chondrocytes isolated from permanent cartilage were seeded at low density and grown in MEM medium containing 10% fetal bovine serum, 50 micrograms/ml of ascorbic acid and antibiotics, at 37 degrees C under 50% CO2 in air. At 0.3% of low serum concentration, addition of Con A to the culture medium increased by 3- to 4-fold the incorporation of [35S] sulfate into large chondroitin sulfate proteoglycan that characteristically found in cartilage. Chemical analysis showed a 4-fold increase in the accumulation of macromolecular containing hexuronic acid in Con A-maintained cultures. The effect of Con A on [35S]sulfate incorporation into proteoglycan was greater than that of various growth factor or hormones. Brief exposure of the permanent chondrocytes to Con A (5 micrograms/ml) for 24 hours and subsequent incubation in its absence for 5-10 days resulted in 10- to 100-fold increase in alkaline phosphatase and binding of 1.25 (OH)2 vitamin D3 to cells. Treatment with Con A also resulted in 10- to 20-fold increase in calcium content and 45Ca incorporation into insoluble material. Methyl-D-mannopyranoside reversed the effect of Con A on [35S]sulfate incorporation into proteoglycan and alkaline phosphatase activity. Since other lectins, such as wheat germ agglutinin, lentil lectin, phytohemagglutinin, Ulex europeasu agglutinin and garden pea lectin had been tested to have little effect on [35S]sulfate incorporation into proteoglycans and induction of alkaline phosphatase activity, the Con A action on chondrocytes seems specific. These results indicate that Con A is a potent modulator of differentiation of chondrocytes, which induces the onset on a maturing and a terminal differentiation in chondrocytes, leading to extensive calcification of the extracellular matrix.

Alkaline Phosphatase↗

PubMed1994

[Reorganization of growth-plate-like tissue by isolated chondrocytes in culture].

Growth-plate cartilage is organized into four cellular zones containing resting, proliferating, maturing, and hypertrophic cells. Rabbit chondrocytes were isolated from growth-plate costal cartilage of 4-week-old New Zealand rabbits, the cells (15 x 10(4)) were suspended in 1 ml of Iscove's modified Dulbecco's medium (IMDM) with 10% fetal bovine serum, 50 micrograms ascorbic acid, and 60 micrograms kanamycin (medium A), then transferred to a 15 ml of plastic centrifuge tube, and centrifuged at 1500 rpm for 5 min. The cell pellet was incubated at 37 degrees C under 5% CO2 in air. The cultures reorganized into growth plate-like tissue which could be seen 7-14 days after cell seeding. This growth-plate, histologically, was organized longitudinally into cellular columns and horizontally into four cellular zones containing resting, proliferating, maturing and hypertrophic cells. The hypertrophic cells in the upper were large in size and round or oval in shape, the proliferating and the mature chondrocytes in the lower were small in size and spherical or elongated in shape. These chondrocytes were surrounded by an extensive matrix. Biochemically, DNA content of cultures began to rise on the 2nd day after cell seeding and reached a plateau after 10 days later. The uronic acid content increased from day 4 and reached the maximum on day 15. In contrast in the early culture, alkaline phosphatase activity was extremely low, it began to rise on day 9 and was the highest on day 20. The sequential increase of DNA, uronic acid and alkaline phosphatase contents was analogous to the in vivo changes of growth-plate chondrocytes.

Alkaline Phosphatase↗

PubMed1993

Estradiol administered in a percutaneous gel for the prevention of postmenopausal bone loss.

Sixty-one postmenopausal women were randomized into 3 groups. Two groups of women were treated with estrogen replacement therapy (ERT) by percutaneous administration of estradiol gel at a dosage of 1.25 g and 2.5 g, respectively. The third group of women, receiving no treatment except placebo, was studied concurrently as a control group. Bone mineral density (BMD) was measured by quantitative computed tomography (QCT) in the vertebrae from T12-L3 and hormones (E1, E2, FSH, LH and testosterone) were determined by radioimmunoassay at baseline, then at 6 monthly intervals thereafter. One year of the study has been completed thus far. The results of this study indicate that: (1) loss of BMD in the control group was observed significantly only in surgical menopausal women and no significant loss of BMD was observed in women receiving ERT treatment regimens; (2) decrease of E1 in control group and increase of E1 in the treatment group were both significant. These data suggest that percutaneous ERT may be used in prevention of postmenopausal bone loss, particularly in surgical menopausal women and the increased E1 may play a beneficial role in inhibiting loss of bone mass and relieving menopausal syndrome. Different dosages of estradiol gel which did not create any significant difference between the 2 treatment groups, need a longer period of follow-up.

Administration, Cutaneous↗

PubMed1993

Homotransplantation of testis. A report of 11 cases.

Testis homotransplantation has been carried out in 11 patients since 1986. Of them, 8 suffered from congenital testicular dysplasia and the other 3 from orchiatrophy as a result of orchitis. Preoperatively, manifestations were a small penis, small testes, sexual dysfunction, indistinct secondary sex characteristics and low serum testosterone (1.7-7.35 mmol/L). Three cases had cadaver transplants and 8 had living relatives' transplants. The patients were followed up for 7 months to 4 years. The secondary sex characteristics and sexual function were improved remarkably after transplantation. Serum testosterone increased up to 12.8-18.2 mmol/L. All of 5 married patients resumed sexual intercourse satisfactorily. Three others got married after transplantation and have enjoyed normal sexual functions. Spermatozoa have been found in the semen in 3 of the cases.

Adult↗

PubMed1993

Snoring and sleep apnoea in men: association with central obesity and hypertension.

The objective of this study was to examine the relationship between sleep apnoea, measures of obesity and blood pressure. The study was cross-sectional in design, involving 1464 consecutive men undergoing sleep studies at two non-hospital sleep laboratories. Detailed sleep studies, body mass index (BMI), neck, hip and waist circumferences and morning and evening blood pressures were measured in each patient. Twenty-eight per cent of patients were obese (BMI > 30 kg/m2) and 47% were overweight (BMI 26-30 kg/m2). Body fat distribution in these patients was typically central with a mean waist-hip ratio (WHR) for the entire group of 0.99 with over 80% of patients having a WHR more than 0.94. Increasing severity of sleep apnoea measured either by respiratory disturbance index (RDI) or minimum oxygen saturation in sleep (MOS) was associated with increasing central obesity and morning but not evening blood pressure. Normal weight patients (BMI < 25 kg/m2) with sleep apnoea were characterized by increased waist and hip circumferences and increased morning diastolic blood pressure compared to patients without sleep apnoea. The best explanatory variables for sleep apnoea were waist (r2 = 0.156, P < 0.001) and age (r2 = 0.013, P = 0.003) only. Morning but not evening blood pressure was related to sleep apnoea independently of obesity and age. We concluded that patients with sleep apnoea are centrally obese. Waist circumference is a better predictor for sleep apnoea than neck circumference or BMI suggesting that the link between obesity and sleep apnoea cannot be explained solely by neck fat deposition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Transient hyperprolactinemia in gonadotropin-stimulated cycles for in vitro fertilization and its effect on conception.

The significance of transiently increased serum prolactin (PRL) levels on pregnancy rates in vitro fertilization (IVF) is unknown. The aim of this study was to evaluate PRL levels in IVF patients who conceived and in matched controls who did not. Ten IVF cycles resulting in pregnancy and forty nonpregnant cycles were compared. Prolactin was measured before ovarian stimulation with gonadotropins and estradiol (E2), progesterone (P) and PRL were measured 36 hours, 12 hours, 10 minutes before and 12 hours after human chorionic gonadotropin (hCG) administration at mid-cycle. Serum PRL levels at various time were not significantly higher in the nonpregnant women than in the pregnant women. Twelve hours before hCG, P levels were significantly higher in the nonpregnant women than in the pregnant women (1.5 +/- 0.2 ng/ml [mean +/- standard error] and 0.9 +/- 0.3 ng/ml, respectively; P < 0.05). All women had transient hyperprolactinemia for one to three times during ovarian hyperstimulation. There was no correlation between PRL and E2 in either group. These results do not support the treatment of transient hyperprolactinemia with dopamine agonists in IVF patients.

Chorionic Gonadotropin↗

PubMed1992

Defibrase, a purified fibrinolytic protease from snake venom in acute myocardial infarction.

To investigate the thrombolytic effects of defibrase in AMI, 157 pts with AMI were studied. Of the 157 pts, 87 were assigned to defibrase thrombolysis and 70 to the conventional therapy plus heparin (control). Coronary arteriography was performed in 36 pts of the defibrase group and 26 of the control group. Pretreatment coronary arteriography was performed in 10 pts and total occlusion of infarct-related artery (IRA) was demonstrated in 7. Thirty to 45 min after either intracoronary or intravenous defibrase thrombolysis, recanalization occurred in 4 of the 7 pts. The perfusion and stenosis was improved in 2 of the 3 pts with patent IRA. Of the 10 pts who underwent emergency coronary arteriography after the onset of i.v. defibrase thrombolysis, 6 were shown to have patent IRAs. Of the 16 pts who underwent coronary arteriography two weeks after the i.v. defibrase thrombolysis, 13 were shown to have patent IRAs. In contrast, only 11 of the 26 pts in the control group had patent IRAs two weeks after admission to the hospital. Of the 36 angiographic cases of the defibrase group, 15 underwent follow-up coronary arteriography, only 1 pt showed reocclusion. In comparison to the control group, the pts in the defibrase group had earlier CPK peaking, higher percentage of pts with LVEF > 0.5, a lower mortality and complication rate. Major spontaneous bleeding complications were rarely seen with defibrase. The results indicate that defibrase is an effective thrombolytic agent with a reasonable recanalization rate, low reocclusion rate and a low rate of bleeding complications.

Batroxobin↗

PubMed1991

Freezing of phosphocholine headgroup in fully hydrated sphingomyelin bilayers and its effect on the dynamics of nonfreezable water at subzero temperatures.

Differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy are applied to characterize the nonfreezable water molecules in fully hydrated D2O/sphingomyelin at temperatures below 0 degrees C. Upon cooling, DSC thermogram displays two thermal transitions peaked at -11 and -34 degrees C. The high-temperature exothermic transition corresponds to the freezing of the bulk D2O, and the low-temperature transition, which has not previously been reported, can be ascribed to the freezing of the phosphocholine headgroup in the lipid bilayer. The dynamics of nonfreezable water are also studied by 2H NMR T1 (spin-lattice relaxation time) and T2e (spin-spin relaxation time obtained by two pulse echo) measurements at 30.7 MHz and at temperatures down to -110 degrees C. The temperature dependence of the T1 relaxation time is characterized by a distinct minimum value of 2.1 +/- 0.1 ms at -30 degrees C. T2e is discontinuous at temperature around -70 degrees C, indicating another freezing-like event for the bound water at this temperature. Analysis of the relaxation data suggest that nonfreezable water undergoes both fast and slow motions at characteristic NMR time scales. The slow motions are affected when the lipid headgroup freezes.

Calorimetry, Differential Scanning↗

PubMed1991

Buserelin treatment of endometriosis in Chinese women.

Twenty five patients with endometriosis of varying degree had been treated with Buserelin (GnRH analogue) for 6 months. Among them, 83.4% reached castrated level by measuring the serum estradiol (E2) 2 months after therapy. Dysmenorrhea was alleviated or completely disappeared during therapy. Hot flush was the one mostly complained. Vaginal dryness was the second and decreased libido the third. Persisted periodic bleeding was noted in 3 patients. Ovulation was suppressed as evidenced by low serum progesterone throughout the whole course of treatment. Second-look laparoscopy was done at the end of 6-month therapy. Scoring assigned by the American Fertility Society (AFS) was reduced by 27.5%. The adrenal gland, liver and renal functions as well serum calcium and phosphate were retained at the end of treatment. Ovulation and menstruation also returned to normal within 2 months after cessation of therapy. There were 4 pregnancies during the 6-month follow period (4/15 = 26.6% pregnancy rate). 7 patients had improved symptoms whereas 7 patients sustained recurrent dysmenorrhea. The hormonal profile showed that dysmenorrhea improved group had better ovarian suppression than the dysmenorrhea recurrent group.

Adult↗

PubMed1991

Adrenal autotransplantation with A-V anastomosis for treatment of Cushing's disease. A follow-up study of 31 cases.

Thirty-one patients with Cushing's disease were treated with bilateral adrenalectomy and partial left adrenal autotransplantation with A-V anastomosis. They were followed up for 1 to 5 years. Three patients failed after adrenal autotransplantation to the abdominal muscle with the left gland's central vein anastomosed to the inferior epigastric artery. Twenty-eight patients underwent adrenal autotransplantation to the omentum with the gland's vein anastomosed to the gastroepiploic artery. Steroid could be omitted a short period after operation and life-long replacement therapy was avoidable in most patients. A few patients subsequently developed hypocorticalism. Two died and one had recurrence of Cushing's disease. Clinical and animal experimental results showed that the omentum is suitable for adrenal autotransplantation with A-V anastomosis. Transabdominal bilateral adrenalectomy and adrenal autotransplantation to the omentum with A-V anastomosis are acceptable in the treatment of Cushing's disease. The subsequent development of hypocorticalism and recurrence of Cushing's syndrome are also discussed.

Adolescent↗

PubMed1991

The 1958 and 1987 ARA revised criteria for rheumatoid arthritis in Chinese patients. A comparative study.

The American Rheumatism Association (ARA) 1958 and 1987 criteria for the classification of rheumatoid arthritis (RA) were applied to 111 consecutive RA patients and 54 patients with non-RA connective tissue diseases from three hospitals of tertiary level in Beijing. Comparison of the two criteria showed that the specificity was the same, being 88% for both, whereas the sensitivity varied from 94% of the 1958 criteria to 91% of the 1987 criteria. Factors affecting the sensitivity were morning stiffness for more than one hour and increase of number of swollen joints from one to three in the 1987 revised criteria.

Adolescent↗

PubMed1991

What factors explain racial differences in lung volumes?

In order to examine the physical characteristics that may determine racial differences in lung volumes, we studied healthy, nonsmoking Caucasian, Chinese and Indian males of similar ages (range 18-51 yrs). We measured spirometric function, flow volume curves, lung volumes, inspiratory and expiratory muscle pressures, alveolar distensibility and diffusing capacity, together with height, weight and fat free mass. Chest shape was measured using radiographs. The mean total lung capacity and vital capacity in the Caucasian group, expressed as percentage predicted, were 5 and 10% higher than in the Chinese group and 17 and 20% higher than in the Indian group. Chinese values for these measurements were 12 and 10% greater than Indian. We found that Caucasians had higher fat free masses, higher inspiratory and expiratory muscle pressures and wider chests than the other races. The Caucasians and Chinese had longer chests than the Indians. There was no difference in alveolar distensibility or in the diffusion coefficient between the groups. These findings suggest that Caucasians have larger lung volumes than Chinese and Indians because they have increased numbers of alveoli and physically larger chest cavities, and not because of greater alveolar distensibility. Chest dimensions, together with height and race explained 90% of the variation in forced vital capacity and 86% of the variation in total lung capacity. Height multiplied by fat free mass, a "physique factor", previously suggested as the best predictive factor for forced vital capacity in Caucasians, did not account for much of the variation in forced vital capacity between Caucasians and Indians, presumably because it takes no account of differences in chest dimensions.

Adolescent↗