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Biomedical subjects

S C Wu

Publications and source records attributed to S C Wu.

At least 19 recordsLinked to original sources
PubMed1992

Selective reversible and irreversible ligands for the kappa opioid receptor.

(+-)-(5 beta,7 alpha,8 beta)-3,4-Dichloro-N-methyl-N-[3-methylene-2- oxo-8-(1-pyrrolidinyl)-1-oxaspiro[4,5]dec-7-yl]benzeneacetamide (14) and its (5 alpha,7 alpha,8 beta) diastereomer 15 have been synthesized from 1,4-cyclohexanedione monoethylene ketal (1) in 10 steps. Compound 14, which we have designated SMBU-1, was found to bind with moderate affinity (Ki = 109 nM) and good selectivity (mu/kappa = 29) to the kappa opioid receptor, while 15 was only 1/10 as potent as a kappa ligand. Preincubation of brain membranes with 14 resulted in wash-resistant inhibition of kappa-receptor binding (69 +/- 6% of control at 10(-6) M). The ketone precursor trans-N-methyl-N-[5-oxo-2-(1- pyrrolidinyl)cyclohexyl]benzeneacetamide (12) showed a higher kappa-affinity (Ki = 78 nM) and a much higher kappa-selectivity (mu/kappa = 166) than 14. Compound 10, the ethylene ketal precursor of 12, exhibited a similar receptor binding profile to 14, with increased kappa-selectivity (mu/kappa = 55), while ketal 11, being a regioisomer of 10 and an oxygen isostere of the kappa-selective analgesic spiradoline (U-62,066), demonstrated the highest kappa-affinity (Ki = 1.5 nM) and kappa-selectivity (mu/kappa = 468) observed in this series.

Benzeneacetamides↗
PubMed1992

Three years' experience with levonorgestrel-releasing intrauterine device and Norplant-2 implants: a randomized comparative study.

A randomized comparative study of levonorgestrel-releasing intrauterine device (LNG-IUD) and Norplant-2 implants was carried out in 200 women for 36 months. Three thousand one hundred woman-months of use were observed with each device. Only one pregnancy occurred in users of LNG-IUD at the 12th month of use. The change in bleeding pattern was the most frequent reason for discontinuation. The discontinuation rate for irregular bleeding with Norplant-2 was 17.3 and 26.8 at 24 and 36 months, respectively, as compared to 3.3 with LNG-IUD at both 24 and 36 months. The differences were statistically significant. Removal for amenorrhea and pain only occurred in acceptors of LNG-IUD. About 20-40% of women using Norplant-2 had prolonged bleeding through 36 months. The percentage of amenorrhea in LNG-IUD was the highest (29.3%) at the end of two years of use. More than 97% of subjects reported satisfaction with the methods used by themselves.

Adult↗
PubMed1992

The structure of the Mental Health Inventory among Chinese in Taiwan.

This study attempted to ascertain the construct validity and external validity of the Mental Health Inventory in a Chinese population in Taiwan and contrast these results with results obtained from studies of several U.S. populations. In particular, a series of measurement models were specified and evaluated to address the issues of reliability and validity. Data were collected from personal interviews of a probability sample of 1,194 Chinese respondents 14 years of age and older in four townships in southwest Taiwan. The Mental Health Inventory was found to involve two major components: positive well-being and psychological distress. As a hierarchical structure, each component consists of one second-order and two or three first-order factors. The relationships between well-being and distress can be characterized as substantially independent and modestly bipolar depending on the level and specification.

Adolescent↗
PubMed1992

Efficacy of anticholinergic and beta-adrenergic agonist treatment of maximal cholinergic bronchospasm in tracheally intubated rabbits.

Cholinergically induced bronchoconstriction is thought to be a major cause of bronchospasm during anesthesia. We used tracheally intubated rabbits (4-mm endotracheal tube) stimulated with methacholine to assess the efficacy of beta-adrenergic agonist and anticholinergic treatment in reversing the increases in respiratory system resistance. Four groups were compared: (a) inhaled metaproterenol, 20 puffs via metered dose inhaler (0.65 mg/puff); (b) inhaled ipratropium bromide, 20 puffs from a metered dose inhaler (18 micrograms/puff); (c) 2 mg of intravenous atropine; and (d) no treatment after methacholine challenge as a control group. Methacholine increased respiratory system resistance from 0.041 +/- 0.001 (mean +/- SEM) to 0.098 +/- 0.006 cm H2O.mL-1.s-1 (P < 0.001). Whereas beta-adrenergic agonist treatment was ineffective in ameliorating bronchoconstriction, inhaled ipratropium bromide and atropine were highly effective, causing an 86%-88% reversal in the methacholine-induced increase in respiratory system resistance. Both these agents were also effective in improving dynamic compliance. We conclude that inhaled ipratropium bromide is effective in treating cholinergic bronchospasm even when administered via a small endotracheal tube and that the beta-adrenergic agonist metaproterenol is ineffective in rabbits in the face of maximal cholinergic stimulation.

Adrenergic beta-Agonists↗
PubMed1992

Expression of growth factor mRNA in rabbit PVR model systems.

Proliferative vitreoretinopathy (PVR) involves the formation of intravitreal fibrocellular membranes which may lead to traction retinal detachment and blindness. The cellular component of epiretinal membranes originates from the proliferation and migration of cells within the eye. Several growth factors and other cytokines are plausible candidates for directing the processes leading to membrane formation. A reproducible animal model is needed for experimental studies of cytokine expression during PVR induction or treatment. We found that intravitreal injection of > 10(6) mixed mononuclear leukocytes or adherent monocytes along with a trans-scleral incision through the pars plana leads to the development of PVR-like disease in rabbit eyes. The severity of the disease was related to the number of monocytes injected. Typically, organized membranes extending from the incision toward the optic nerve formed within one week. Progression to extensive traction retinal detachment required 1 to 4 weeks. Injection of up to 5 x 10(6) lymphocytes or freeze-thaw killed monocytes was ineffective, and coinjecting 100 micrograms endotoxin with the monocytes did not result in enhanced disease. The histological appearance of the epiretinal membranes was similar to human PVR membranes. Macrophage, cytokeratin-positive (epithelial), and fibroblast-like cells were present. Northern blot analysis of RNA extracted from the rabbit membranes revealed the presence of mRNA for acidic fibroblast growth factor (aFGF). Acidic FGF mRNA was not expressed by the injected monocytes. A comparable level of aFGF mRNA and also mRNAs for basic FGF, platelet-derived growth factor-B, and transforming growth factor beta were found in epiretinal membranes induced by a scleral incision in association with cryopexy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A simple animal model for inducing and releasing surgical jaundice in rats.

Surgical jaundice can be easily induced by ligation of bile duct, but it is not easy to reverse the ligation in rats. Therefore, a simple method was designed in our laboratory to address the problem. Obstruction of bile duct can be achieved by the compression by two arms of a fine silicon tube enveloped in an outer bigger silicon tube. Both silicon tubes are then fixed and sutured to the abdominal peritoneum. Therefore, if the releasing of the obstruction is required, removal of the inner fine silicon tube by removing off the previous suture tire of silicon tube which had settled under the skin. Thus, the reversing of obstruction could be achieved without extensive exploration into the abdominal cavity. One week after obstruction the bile duct of rats were dialated 6.10 +/- 1.26 mm (Mean +/- SD) in rats. The serum bilirubin and alkaline phosphatase were 6.29 +/- 1.26 mg% and 229.30 +/- 82.22 IU respectively. The dilated bile duct decreased into 3.00 +/- 0.98 mm one week after decompress with this method. Serum bilirubin and alkaline phosphatase were 1.80 +/- 0.79 mg% and 90.50 +/- 19.60 IU respectively. It proved that this animal model was simple and had the benefit of being able to sample the bile without contamination with intestinal contents after decompression.

Alkaline Phosphatase↗
PubMed1991

Antibodies to hepatitis C virus in uremic patients on continuous ambulatory peritoneal dialysis.

The prevalence of antibody to hepatitis C virus (anti-HCV) among 101 uremic patients receiving continuous ambulatory peritoneal dialysis (CAPD) was evaluated using a synthetic peptide-based HCV antibodies enzyme immunoassay. Thirty (29.7%) were found anti-HCV positive. This is significantly higher than 500 unselected paid blood donors (4.2%, P less than 0.0001). Among CAPD patients, anti-HCV positivity was found more frequently in patients who had received frequent and longer duration of hemodialysis previously (40.4% vs. 20.4%, P less than 0.05). These findings suggest that hemodialysis patients have a higher risk of HCV infection. At present, CAPD may be a suitable way to reduce the incidence of HCV infection in uremic patients.

Adolescent↗
PubMed1991

Polychotomous multivariate models for coronary heart disease simulation. I. Tests of a logistic model.

Stochastic compartmental modeling techniques have been employed to simulate coronary heart disease morbidity and mortality. In the current paper, polychotomous logistic models are used to describe the relationship between risk of disease and multiple risk factors, effect modification and confounding variables. The process of estimating the parameters for two risk factors and three types of outcomes is described for a population followed for five years. A Statistical Analysis System (SAS) procedure was used to estimate risk factor coefficients based on two partial periods and on the entire five year epoch. Most of the estimated coefficients were found to be statistically significant. The model performance was evaluated by comparing the observational data with simulated outcomes using a micropopulation and Monte Carlo techniques. Two different tests of goodness of fit were used. Satisfactory fits were obtained both for the risk coefficients based on two partial periods and those based on the entire epoch. This indicates that the model is suitable for simulation of the effects of intervention strategies. The use of the entire epoch involved estimates of one half as many parameters as did the use of two partial periods. Accordingly, it is concluded that only the entire epoch need be considered for future studies of this population.

Adult↗
PubMed1991

Fabrication and biocompatibility of a porous bioglass ceramic in a Na2O-CaO-SiO2-P2O5 system.

A porous bioglass ceramic was prepared from a finely pulverized bioglass powder mixed with particles of two sizes (5 and 500 microns) of 30% by weight with the foaming agent polyethylene glycol 4000 (HO (C2H4O) nH). The batch composition of the bioglass was Na2O 12%, CaO 28%, SiO2 50% and P2O5 10% by weight. The specimens, formed by pressing, were sintered in a high temperature furnace. In this study we are concerned with the preparation and microstructure of the material and its performance in biological tests. The microstructure and crystalline phases of the material were investigated by differential thermal analysis, X-ray diffraction analysis, transmission electron microscopy and scanning electron microscopy. In a biomedical examination, it was shown that the porous material was compatible with animal tissues. The microstructure of the implant indicated that newly grown bone interlocked well with the glass ceramic and that macropores and micropores were distributed uniformly in the material, which provided channels for bone ingrowth and improved the microscopic bioresorption.

Animals↗
PubMed1991

[An assessment of patients hospitalized for burn injuries].

To study the causes of burn injuries and the nature of their medical treatment, we investigated the medical histories of hospitalized patients admitted to the burn center of Taipei City Ho-Ping Hospital from June 6, 1983 to June 6, 1987. Additionally, a phone interview follow-up on recovery conditions was made. Among the 300 patients admitted, the majority (53.7%) were burned by scalding water, while fire was the second most common cause of burns. The rate of incidence was highest for those aged 0-4 years, and 90% of this age group were victims of scalding. For all age groups, 78.9% of the burns resulted from negligence, with most accidents occurring in a kitchen, factory or workplace, or a bathroom. Men's burns were more severe than women's burns on average. Severe fire burns constituted half of the cases. The majority of the burns affected the front of the limbs, torso, head and neck. The degree of the burns was mixed, but second degree burns were most prominent (36%). Sixty percent of the patients were burned over less than 10% of their body surface. Seasonality was not evident, but most cases occurred between noon and eight o'clock in the evening. Patients with electric burns had the longest hospital stays, averaging 30.5 days, while those burned by scalding had the shortest (16 days). Those with severe burns average 26.5 days. Half (50.7%) of the patients recovered by the time they left the hospital. Examining the death rate by type of burn, we found that the death rate for chemical burns was the highest (10.34%), while the rate was lowest for scalding.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Inconsistent effectiveness of myocardial preservation among cardiac chambers during hypothermic cardioplegia.

The purpose of this study was to examine the selective and differential natures of ischemic injuries among three cardiac chambers (right atrium, right ventricle, and left ventricle) from the viewpoint of ultrastructural morphometric study. Twenty consecutive adult patients undergoing cardiac operations were studied. The duration of aortic crossclamp time varied from 36 to 142 minutes (mean 83.4 +/- 36.4 minutes). Two serial specimens (preischemic and ischemic) were obtained from the right atrium, the right ventricle, and the left ventricle, respectively. A total of 120 biopsy specimens was obtained from these 20 patients. The average mitochondrial surface area of the left ventricle was 0.308 +/- 0.062 micron 2 in the preischemic stage and 0.352 +/- 0.083 microns 2 in the ischemic stage. This represented a 14.3% increase in mitochondrial surface area after ischemic injury (p less than 0.01). The mitochondrial surface area of the right ventricle showed an average increase of 43.7%, from 0.252 +/- 0.036 micron 2 in the preischemic stage to 0.362 +/- 0.087 micron 2 in the ischemic stage (p less than 0.0005). With respect to the mitochondrial surface area of the right atrium, there was an increase of 88.0%, from 0.217 +/- 0.044 micron 2 in the preischemic stage to 0.408 +/- 0.084 micron 2 (p less than 0.0005). The difference of mitochondrial swelling among three chambers was statistically significant (right atrium versus right ventricle versus left ventricle, p less than 0.0005). Moreover, the differences of mitochondrial swelling between any two chambers were also highly significant (right atrium versus right ventricle, p less than 0.0005; right ventricle versus left ventricle, p less than 0.01; right atrium versus left ventricle, p less than 0.0005). In conclusion, our findings suggest that from the viewpoint of ultrastructural morphometric study myocardial injury after an average of 83 minutes of ischemic arrest is poorer in the right chambers of the heart than in the left ventricle, with the right atrium having the poorest preservation.

Adult↗
PubMed1990

Comparison of the clinical performance, contraceptive efficacy and acceptability of levonorgestrel-releasing IUD and Norplant-2 implants in China.

The levonorgestrel-releasing IUD (LNG-IUD, 20 micrograms/d) and the Norplant-2 implants were studied in a randomized comparative clinical trial with 200 women for one year. No pregnancy or expulsion occurred with the Norplant-2. In the LNG-IUD group, there was one pregnancy at the 12th month of use after an unnoticed expulsion. The net cumulative pregnancy and expulsion rates of LNG-IUD were 1.0 and 3.0. The removal rate due to menstrual disturbances in both LNG-IUD and Norplant-2 groups was 3.0. The use-related discontinuation rates were 9.0 and 3.0, and the continuation rates were 90.0 and 96.0, respectively. The differences were not statistically significant. Menstrual disturbance was the main side effect. It was improved after long time use, especially in the LNG-IUD group. After one year, the percentages of women with amenorrhea were 18.9 for the LNG-IUD and 8.3 for the Norplant-2. The menstrual blood loss was statistically significantly reduced in the LNG-IUD group, and blood haemoglobin concentration increased in both groups. The LNG-IUD and Norplant-2 are highly effective, safe, long-acting, and well accepted by the Chinese women.

Administration, Intravaginal↗
PubMed1990

Reduction of serum calcium by sodium sulfonated polystyrene resin.

Sodium resin has been clinically administered against hyperkalemia widely, but its effects of lowering the serum calcium has never been documented. In our study, 7 patients with chronic renal failure were chosen at random to take sodium resin 30 g per day for 3 days. The sodium resin not only lowered the serum potassium level (p less than 0.05) but also brought down the level of serum calcium (p less than 0.05). The reduced ability of patients with chronic renal failure to absorb calcium from the gastrointestinal tract is well recognized, so its effects of lowering calcium will be more likely to aggravate the serum calcium imbalance further. If sodium resin has to be used for the maintainance of serum potassium in patients with chronic renal failure the serum calcium should be monitored closely in order to lighten the osteodystrophy and secondary hyperparathyroidism.

Adult↗
PubMed1990

Secondary prevention of ischemic stroke with low dose acetylsalicylic acid.

In order to evaluate the efficacy of low dose acetylsalicylic acid (ASA) for the secondary prevention of ischemic stroke, this cooperative multicenter clinical trial was conducted on a non-blind basis. Patients having a first transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND) or completed ischemic stroke were eligible for this trial. A total of 590 patients including 47 cases of TIA, 23 cases of RIND and 520 cases of completed stroke entered this study. These patients were allocated by the time of admission to one of the following 5 trial regimens: (1) vasodilators having no known inhibitory effect on platelet function (control group), (2) dipyridamole (DP) 50 mg 3 times a day (DP group), (3) ASA 300 mg once a day (ASA 300 mg group), (4) ASA 300 mg once in combination with DP 50 mg 3 times a day (ASADP group), and (5) ASA 100 mg once a day (ASA1 group). No difference in effect between the control and DP groups was observed, nor between the ASA 300 mg and ASADP groups. Therefore, we combined the control and DP groups to make a non-ASA group, and joined the ASA 300 mg and ASADP groups to make an ASA3 group. The differences in the cumulative event-free rate appeared to be significant between the non-ASA group and the ASA3 group and also between the non-ASA group and the ASA1 group. But the frequency distribution of age, territory of stroke, diabetes mellitus, cardiac disease, hematological disease and hyperuricemia were significantly different among these 3 study groups. We thus included these covariates in the Cox's proportional hazard model to control their possible confounding effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Histological evaluation of biocompatible orthopaedic polymer.

The biocompatibility of biocompatible orthopaedic polymer implant materials was studied in subcutaneous and bony tissue of rats and rabbits. The tissue response was evaluated by histological techniques. No bone induction capacity of biocompatible orthopaedic polymer could be observed. In rabbits, the presence of plasma cells was significantly higher than in rats. The biomaterial showed some signs of biodegradation and was not very biocompatible.

Animals↗
PubMed1990

Neuro-Behçet's disease: report of three cases with a review of the literature.

We report three cases of neuro-Behçet's disease, including one woman and two men (age range 52-56 years), who displayed symptoms of high fever, headache and confusion. The EEG showed generalized slowing in two cases, and periodic lateralized epileptiform discharges in one. Brain CT scans from two patients revealed cortical atrophy with multiple low density areas in one case, and focal contrast enhancement in the other. The CSF study revealed pleocytosis in all cases, but only one showed lymphophagocytosis. All of the patients responded dramatically to steroid therapy, although administration of the drug was somewhat delayed in two cases, during which initial management was aimed at the CNS infection of bacterial origin. Recurrent attacks of confusion or mental dullness were found in two patients, and high cortical dysfunction persisted on follow-up for some time. The clinical manifestations, laboratory findings, and neuroradiological features of neuro-Behçet's disease in the reported cases are reviewed.

Behcet Syndrome↗
PubMed1989

Polyadenylated H3 histone transcripts and H3 histone variants in alfalfa.

Histone H3 mRNAs were found in polyA(+) fractions of total RNA prepared from alfalfa plants, calli and somatic embryos. The sequence analysis of cDNAs revealed the presence of a polyA tail on independent alfalfa H3 mRNAs. A highly conserved sequence motif AAUGAAA identified about 20bp upstream from the 3' ends of the alfalfa H3 cDNAs was suggested to be one of the possible regulatory elements in the 3' end formation and polyadenylation. Three out of the four analysed H3 cDNAs have more than 97% homology with a genomic clone and encode the same protein. While the fourth represents a minor species with only 78.8% homology to the coding region of the genomic clone and encodes a H3 histone with four amino acid replacements. On the basis of compilation analysis we suggest a consensus sequence for plant H3 histones which differs from that of animal's by four amino acid changes.

Amino Acid Sequence↗