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Biomedical subjects

H Chiang

Publications and source records attributed to H Chiang.

At least 73 records · Page 4Linked to original sources
PubMed1994

The clinicopathological correlation of epithelial subtyping in thymoma: a study of 112 consecutive cases.

The clinicopathological features of 112 thymomas collected from the surgical pathological files of Taipei Veterans General Hospital from 1961 to 1991 were investigated to determinate the clinical efficacy of epithelial subtyping. All thymomas were categorized based on the Müller-Hermelink system into three subtypes: cortical thymoma, mixed thymoma, and medullary thymoma. The former was further subclassified into organoid thymoma, conventional cortical thymoma, and well differentiated thymic carcinoma (WDTC) according to the systems of Pescarmona and Kirchner. The association of each subtype with sex, age at diagnosis, clinical stage, presence of myasthenia gravis, and length of survival was studied. As classified by the Müller-Hermelink system, the cortical thymomas as a whole tended to occur in younger patients and were more frequently associated with myasthenia gravis than the medullary thymomas. The cortical thymomas also showed a propensity to be invasive in nature, whereas the medullary thymomas generally behaved as benign tumors. Further subclassification of cortical thymomas into organoid thymoma, conventional thymoma, and WDTC did not provide more information about clinical behavior. By Kaplan-Meier's actuarial survival analyses none of the epithelial subtypes displayed a statistically significant influence on prognosis. It is concluded that staging remains the most important factor affecting the patient's outcome. Because of the existence of many intermediate forms and the deficiency of clinical relevance, the subclassification of cortical thymomas should be interpreted as a morphological continuum rather than as distinct histological variants.

Adolescent↗
PubMed1994

The effects of in vitro and in vivo exposure to insulin upon prostaglandin E1 stimulation of platelet adenylate cyclase activity in healthy subjects.

Insulin treatment of platelets is associated with increased prostaglandin E1-stimulated adenylyl cyclase activity and decreased platelet aggregation. Because non-insulin dependent (Type II) diabetes mellitus is associated with hyperinsulinemia, we sought to determine the effect of insulin treatment in vivo and in vitro upon stimulation of platelet adenylyl cyclase by prostaglandin E1. Incubation of platelet-rich plasma obtained from normal subjects with 2 microM prostaglandin E1 resulted in a 16-fold increase in cAMP accumulation. Pre-incubation of platelet-rich plasma with 0.7 nM insulin resulted in a 62% increase in prostaglandin E1 (2 microM)-stimulated cAMP accumulation (p < 0.005). Pretreatment of platelets with cholera toxin prior to incubation with insulin had no effect on subsequent prostaglandin E1-stimulated cAMP accumulation. By contrast, pretreatment of platelets with pertussis toxin prior to incubation with insulin resulted in a nearly 2-fold increase in prostaglandin E1-stimulated cAMP accumulation (p < 0.005). To determine whether platelets exposed in vivo to elevated concentrations of insulin would show similar responses, we isolated platelet-rich plasma from subjects before and after a 120 minute euglycemic clamp study in which insulin was infused (40 mU m-2min-1) intravenously. Patients who underwent the euglycemic clamp study achieved steady state serum levels on insulin of 0.70 +/- 0.19 pmol/ml. Platelets obtained after insulin infusion had a 65% increase in prostaglandin E1-stimulated cAMP. Our results indicate that serum levels of insulin that are common in patients with type II diabetes mellitus can increase the sensitivity of platelet adenylyl cyclase to stimulation by prostaglandin E1.

Adenylate Cyclase Toxin↗
PubMed1993

Deoxyribonucleic acid histogram of testes in primary transsexualism.

The influence of oestrogen on spermatogenesis was evaluated by comparing its effect on the testes of primary male transsexuals and those who had undergone hormone therapy for prostatic carcinoma. Eight primary transsexuals were studied. They had been diagnosed on clinical and psychiatric evidence and had been on oestrogen therapy for several years since puberty. Histological sections of testicular tissue obtained at reassignment surgery from 8 phenotypic male transsexuals (aged 24-32 years) with an XY chromosome complement were studied by light microscopy. The formalin-embedded specimens were analysed by flow cytometry for deoxyribonucleic acid (DNA) histograms. Both the histology and DNA histograms revealed a pattern of maturation arrest in 12 of 16 testes in which the diploid cell compartment occupied most of the spermatogenetic element, followed by tetraploid and monoploid cells. Two testes showed impaired spermatogenesis and 2 were normal. The DNA histograms and pathology were also evaluated in 20 testes after 3 to 8 years of hormone therapy in patients with advanced prostatic carcinoma (aged 60-78 years). No maturation arrest was found in these patients. Sixteen of them had a pattern of fibrosis and atrophy and 4 had impaired spermatogenesis. It was concluded that oestrogen influenced spermatogenesis and affected the maturation of spermatogonia mostly during puberty.

Adult↗
PubMed1993

Creutzfeldt-Jakob disease. Report of a case of the panencephalopathic type and experiences of a teaching hospital in Taiwan.

We report a case of the unusual panencephalopathic type of Creutzfeldt-Jakob disease (CJD) in Taiwan. This 59-year-old woman presented in 1983 with typical clinical manifestations of CJD and died 16 months later. Postmortem examination revealed severe neuronal loss, spongiosis and gliosis extensively in cerebral cortex and striatum as well as in the white matter. We also report 6 other CJD patients seen from 1983 to 1991 at Veterans General Hospital-Taipei.

Aged↗
PubMed1993

Amelioration of antioxidant enzyme suppression and proteinuria in cyclosporin-treated puromycin nephrosis.

The effect of cyclosporin (CS) on intrinsic glomerular level of antioxidants in puromycin aminonucleoside (PAN) nephrosis was examined. A single intravenous dose of PAN (50 mg/kg body weight) given to Sprague-Dawley rats resulted in marked proteinuria. Ten days after PAN injection, the rats were treated with daily intraperitoneal injection of CS (10 mg/kg body weight/day) for 10 days. PAN-treated rats without CS treatment (PAN rats) had significantly lower activities of glomerular superoxide dismutase (SOD) and catalase (CAT) than normal rats (p < 0.05, respectively). When compared with PAN rats, CS-treated PAN rats had significantly less proteinuria and higher activities of glomerular SOD and CAT (p < 0.01 and p < 0.05, respectively). Significant elevation of glomerular malondialdehyde (MDA) level characteristic of PAN rats was absent in CS-treated PAN rats. Moreover, segmental sclerosis with capsular adhesion, hyalinosis, epithelial cell foot process fusion and microvillous transformation seen in PAN rats were apparently attenuated in CS-treated PAN rats. When compared with normal rats, rats receiving CS only had a significantly higher CAT activity and MDA level (p < 0.01 and p < 0.05, respectively). Assessment of glomerular reduced glutathione revealed no significant differences among PAN rats, CS-treated PAN rats, normal rats, and rats receiving only CS. These data indicate that glomerular antioxidant enzyme activities are modulated by CS.

Animals↗
PubMed1993

[VDT pulse magnetic field enhances teratogenic effect of ara-c in mice].

Impregnated NIH mice were irradiated 4 hrs daily on days 16th-17th of gestation with 15.6 kHz pulse magnetic field at 40 microT peak to peak. Significant enhancement of ara-c induced teratogenic potency by the magnetic field can be observed. The incidence of harelip fetuses bearing harelip and/or cleft palate was significantly higher in the combined exposure group, in which mice were exposed to the magnetic field and given an intraperitoneal injection of ara-c on the 9th day of gestation, than that of mice treated with ara-c alone.

Abnormalities, Drug-Induced↗
PubMed1993

Program description and preliminary health survey data in Kin-Hu, Kinmen.

The study subjects were those over 30 years of age in Kin-Hu, Kinmen. From January to February 1991, demographic data, physical data, life style and blood chemistry parameters were collected from 2929 respondents (1368 men and 1561 women) out of 4475 eligible subjects. The study, conducted by the Yang-Ming Crusade, used a structured questionnaire and venipuncture technique. After clarifying missing values, a total number of 2868 (64.1%; 1334 men and 1534 women) subjects had completed the data set. Of the total subjects, 32.3% were 30-39 years of age, 24.3% were 40-49 yrs, 22.4% were 50-59 yrs, and 21.0% were above 60 years old. Fifty-two percent of men and 2.8% of women, were current smokers. Most of the surveyed subjects described themselves as having infrequent physical activity (men vs. women, 66.4% vs. 81.0%, p < 0.001). Men had significantly lower body mass index (BMI) and higher waist-hip ratio (W/H) than women (BMI: 22.9 +/- 3.2 vs. 23.2 +/- 3.7, p < 0.01; W/H: 0.89 +/- 0.06 vs. 0.84 +/- 0.07, p < 0.01). Men also had higher fasting plasma glucose (FPG), systolic/diastolic blood pressure (SBP/DBP) than women (FPG: 99 +/- 25.3 vs. 95.7 +/- 25.3 mg/dl, p < 0.0001; SBP: 132.1 +/- 19 vs. 126.4 +/- 21.5 mmHg, p < 0.0001; DBP: 80.4 +/- 12.5 vs. 76.5 +/- 12.3 mmHg, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Rapid quantification of adenosine cyclic 3',5'-monophosphate by competitive enzyme-linked immunosorbent assay.

A reliable and rapid enzyme-linked immunosorbent assay (ELISA) for cyclic AMP determination is described. Succinyl cyclic AMP, coupled to human albumin, was injected into rabbit to elicit antibodies to cyclic nucleotide hapten. Succinyl cyclic nucleotide to human albumin as immunogen or the cyclic AMP to porcine thyroglobulin as coating antigen was conjugated by a carbodiimide coupling procedure. The latter conjugate, captured to microplate with coating buffer and blocked with 0.8% gelatin for 30 minutes, was bound to antibody in inverse proportion to free cyclic AMP in a sample or standard. Bound antibody was then quantified with horseradish peroxidase-labelled goat antirabbit immunoglobulin and ABTS (2, 2'-Azinobis (3-ethylbenzthiazolinesulfonic Acid). Our results showed that concentration of both standard and sample cyclic AMP could be measured as low as 2.5 fmol/well (0.05 pmol/ml). The intra- and inter-assay coefficients of variation for samples were 6.0-8.0% and 8.9-9.5%, respectively. In addition, there was no cross-reaction of the antisera with ADP, ATP, 5'-AMP or cyclic GMP. Short period of incubation at room temperature seems as good as long period of incubation at 4 degrees C. The biological study demonstrated a consistency between increase in platelet-cyclic AMP generation after prostaglandin E1 stimulation and its biological effects. Our approach to ELISA is validated by showing agreement in levels, obtained in parallel by ELISA and RIA, of cyclic AMP content in extracts of prostaglandin E1-stimulated platelet cells.

Cyclic AMP↗
PubMed1993

The characterization of adenyl cyclase activity in FRTL-5 cell line.

The purpose of this study is to characterize the adenyl cyclase (AC) activity in Fisher rat thyroid cell line when stimulated with several agonists, such as: forskolin, sodium fluoride, Gpp(NH)p (guanosine-5'-(beta, gamma -imino) triphosphate or thyrotropin. The following studies such as: dose-response, pH, temperature, time-response, millieu concentration, 3H-thymidine uptake, Km and Vm study were also performed. Adenyl cyclase activity was measured as adenosine 3', 5'-cyclic monophosphate generated by cell cultures in 120- minutes incubation at 37 degrees C. The basal AC activity was 15.0 +/- 7.0 (mean +/- SEM, n = 6) pmol/100,000 cells/120 minutes. Forskolin at 0.1 mM increased the AC activity to 10 folds of basal AC activity. Thyroid stimulating hormone at 1 mU/ml and 10 mU/ml increased the AC activity 2 and 15 folds, respectively. Sodium fluoride stimulation study demonstrated dual actions of fluoride on adenylate cyclase; when the cells were assayed with increasing concentration of NaF, the AC activity increased as the concentration of NaF increased from 0.01 to 1 mM, but decreased strikingly as that concentration increased from 1 mM to 100 mM. When the concentration of nonhydrolyzable guanine nucleotide analogs increased in the presence of TSH, there was first an increase in adenylate cyclase activity, followed by a decrease at higher concentration. The amount of cAMP generation was much higher (P < 0.05) in hypotonic than in isotonic millieu. When the incubation temperature raised to 56 degrees C, all the AC activity was diminished. The optimal pH for AC activity was in the range of 7.4 and 8.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1993

Hepatic actinomycosis with portal vein thrombosis mimicking hepatocellular carcinoma: a case report.

A fatal case of hepatic actinomycosis with portal vein thrombosis is reported. The diagnosis of actinomycosis was delayed because of its rarity in Taiwan. This 63-year-old man was admitted due to body weight loss and poor appetite. No fever was noted before admission. Liver biochemical test showed a decreased serum albumin level with elevated serum levels of globulin and alkaline phosphatase. He was not a hepatitis B carrier and his serum level of alfafetoprotein was within normal range. Image studies (abdominal sonography and computed tomography) showed a hepatic mass over the medial segment of the left lobe with involvement of right lobe of the liver. Main portal vein thrombosis was also seen. Because of profound cachexia, he died of aspiration pneumonia and disseminated intravascular coagulation on the 11th day after admission. An autopsy revealed hepatic actinomycosis. High index of suspicion for early diagnosis and treatment is emphasized.

Actinomycosis↗
PubMed1992

Correlation of contractile function and passive properties of rabbit urinary bladder subjected to outlet obstruction--an in vitro whole bladder study.

The present study investigated the correlation between contractile function and passive properties of rabbit urinary bladder subjected to outlet obstruction. Mild bladder outlet obstruction was induced by placing silicone rings (7 mm. diameter) around the bladder necks of male New Zealand rabbits. The animals were sacrificed after 2 weeks of obstruction. Contractile function was evaluated by measuring the response of the in vitro whole bladder to 500 microM bethanechol administration. Passive properties was assessed by performing in vitro cystometry and stress-relaxation techniques utilizing six different infusion rates. When the intravesical pressure reached 30 cm. H2O the infusion was stopped, allowing the bladder to relax and intravesical pressure to drop to a steady state level. The results can be summarized as follows: 1) Although the intravesical pressure response to bethanechol was about the same in control (13.3 cm. H2O) and obstructed (12.4 cm. H2O) bladder, the obstructed bladder emptied significantly less than control (20.4 vs 89.3%); 2) the results of the passive properties study showed that bladder stiffness was significantly higher at all infusion rates in the obstructed bladder, 3) the obstructed bladder showed significantly less relaxation after rapid stretching of the whole bladder by high speed fluid infusion; 4) histological examination of obstructed bladders revealed marked fibrous thickening of the serosal layer, interstitial fibrosis of the muscle layers, and hypertrophic and/or degenerative changes of the muscle fibers. In summary, 2 weeks after mild outlet obstruction of the urinary bladder the emptying ability, but not pressure generation, was reduced along with increased bladder stiffness and diminished capacity for stress-relaxation. Interstitial fibrosis and changing the properties of the smooth muscle cells might be involved in the functional impairment and deranged viscoelasticity of the urinary bladder after outlet obstruction.

Animals↗
PubMed1992

Determinant role of testosterone in the pathogenesis of urolithiasis in rats.

By using an ethylene glycol-induced urolithiasis model, we assessed the role of testosterone in the pathogenesis of urolithiasis. The intact and castrated male and female rats were fed with 0.5% ethylene glycol in drinking water for four weeks. The renal excretions of oxalate, citrate and other electrolytes were measured, and the stone and crystal deposit were examined microscopically. The results showed that drinking a loading of 0.5% ethylene glycol for four weeks produced hyperoxaluria in all rats, but the intact male rats excreted more urinary oxalate than any other groups of rats. The ethylene glycol-fed rats exhibited hypocitraturia except the castrated male rats. However, urolithiasis occurred in intact male but not female rats. Castration in male rats fed with ethylene glycol dramatically decreased the incidence of renal stone from 71.4% (5/7) to 14.3% (1/7). On the other hand, there was still no renal stone formed in the oophorectomized female rats which received ethylene glycol treatment. These data indicate that serum testosterone level plays a determinant role in urolithiasis formation.

Animals↗
PubMed1992

Detection of antibodies to human immunodeficiency virus (HIV-1) with the particle agglutination test.

This study was designed to evaluate the sensitivity and specificity of the particle agglutination test (PA) for antibody detection and to determine whether it is possible to use this test as a screening routine for anti-human immunodeficiency virus type I antibodies instead of the enzyme linked immunosorbent assay (ELISA). Serum samples were collected from 5,142 subjects and tested with the above two tests. A total of 83 samples were observed to be ELISA-positive. However, only 36 were found to be seropositive by the PA test. These samples were then confirmed by the Western blot analysis and 28 were positive for HIV-1, 33 were negative and 22 gave indeterminate results. The most common indeterminate band was p15/17 and the p24 band came next. The sensitivity and specificity of the PA test were 100% and 99.9%. The results indicate that the PA test is not only a convenient technique but also has a high sensitivity and specificity. It can be used as a primary screening test for antibody against HIV-1 instead of the ELISA.

Agglutination Tests↗