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Biomedical subjects

C J Wang

Publications and source records attributed to C J Wang.

At least 19 recordsLinked to original sources
PubMed1992

Inhibitory effect of geniposide on aflatoxin B1-induced DNA repair synthesis in primary cultured rat hepatocytes.

We have previously demonstrated that geniposide (GP) inhibits the aflatoxin B1 (AFB1) induced-hepatotoxicity and hepatic DNA binding in rats. To address the mechanism of action, the effects of GP on AFB1-induced DNA repair synthesis and AFB1 biotransformation in cultured rat hepatocytes were investigated. By evaluation of unscheduled DNA synthesis (UDS), GP reduced AFB1-induced DNA repair synthesis in a dose-dependent manner in hepatocyte cultures. GP elevates the metabolism of AFB1 and decreases the formation of AFM1. The enzyme activities of glutathione S-transferase (GST) and GSH-peroxidase (GSH-Px) in AFB1-treated hepatocyte cultures are enhanced in the presence of GP. GP reduces AFB1-induced DNA repair synthesis through an increased AFB1 detoxication metabolism. It provides one possible mechanism for the chemopreventive activity of GP.

Aflatoxin B1↗
PubMed1992

Inhibition of penta-acetyl geniposide on AFB1-induced genotoxicity in C3H10T1/2 cells.

A new compound, penta-acetyl geniposide ((Ac)5-GP), was obtained from modified extract of Gardenia fructus (San-Jee-Chee in Chinese). The structure of the compound was identified as 1-(beta-D-2',3',4',6'-tetraacetyl-glucopyrannosyloxyl)-1,4a, 5,7a-tetrahydro-7-(acetomethyl)-cyclopentapyran-4-carboxylic acid methyl ester, according to the spectral data. The inhibitory effects of (Ac)5-GP on aflatoxin B1 (AFB1)-induced cytotoxicity and DNA damage were studied. In the investigation of the inhibitory effect of (Ac)5-GP on AFB1-cytotoxicity, the plating efficiency of C3H10T1/2 cells in S-9 activation system was increased. In addition, (Ac)5-GP inhibited the DNA damage of AFB1-treated C3H10T1/2 cells, and it interfered with the inhibitory effect of DNA synthesis caused by AFB1. These results suggest that the reduced DNA damage and the increased DNA synthesis from cultured C3H10T1/2 cells are important mechanisms for the inhibition of AFB1-cytotoxicity by (Ac)5-GP.

Aflatoxin B1↗
PubMed1992

Effects of cement, cement space, marginal design, seating aid materials, and seating force on crown cementation.

An evaluation of the effects of a die spacer, the seating force, the marginal design, seating aid materials, and the cement type during cementation was conducted. Two stainless steel dies were used: one with a 1 mm shoulder and the other with a shoulder and a 65-degree bevel. Ten stone dies were produced from each metal die and half were painted with four layers of die spacer. The crowns were waxed on the dies and cast in a nonprecious alloy, and the seating of crowns was measured with a micrometer before and after cementation. Comparisons were made between zinc phosphate and glass ionomer cements under two seating forces of 5 and 30 lb using an orangewood stick or E-Z-bite seating aid. ANOVA and the Newman-Keuls test revealed that the use of a die spacer, a heavier force of 30 lb, and glass ionomer cement significantly improved crown seating. The beveled preparation led to superior crown seating when the heavier force or glass ionomer cement was used. The orangewood stick and bite device had a similar effect on crown seating.

Cementation↗
PubMed1992

A competitive enzyme immunoassay for the direct determination of mometasone furoate (SCH 32088) in human plasma.

Mometasone furoate (SCH 32088) is a synthetic corticosteroid which has a topical anti-inflammatory activity with a minimal potential for suppressing hypothalamic-pituitary-adrenocortical (HPA) axis. A sensitive competitive enzyme immunoassay (EIA) for measuring SCH 32088 in unextracted human plasma has been developed. The 3-(O-carboxymethyl)oxime (CMO) of SCH 32088 was synthesized and conjugated with bovine thyroglobulin, and the product was used for the production of antibodies in rabbits. SCH 32088-3-CMO was also conjugated with horseradish peroxidase, which was used as the tracer. The EIA thus developed can detect 1 pg SCH 32088 per assay or 25 pg per ml of human plasma. It can reliably quantitate SCH 32088 in human plasma from 50 pg ml-1 to 2.5 ng ml-1 with good linearity, accuracy and precision. The assay can be extended to measure SCH 32088 in plasma of laboratory animals. The availability of this sensitive assay makes it possible to evaluate the pharmacokinetics and toxicokinetics of SCH 32088 in laboratory animals and man.

Administration, Topical↗
PubMed1992

Perinatal mortality and prevalence of major congenital malformations of twins in Taipei city.

In order to examine perinatal mortality and prevalence of major congenital malformations in twins, deliveries in four teaching hospitals in Taipei City were studied. Among a total of 73,264 deliveries from October 1985 to June 1989, there were 844 pairs of twins. The zygosity of the twin pairs was determined by sex, placentation and 12 red blood cell antigens. There were 482 MZ and 252 DZ twin pairs identified, but the zygosity of a further 110 twin pairs was indeterminable due to lack of information on plancentation and/or blood types. A total of 4,573 singletons delivered in one study hospital from July 1986 to June 1987 were also studied as controls. The perinatal mortality rate was 7.5% for MZ twins, 1.4% for DZ twins, and 0.7% for singletons. The concordance rate of perinatal death was significantly higher in MZ (60%) than in DZ (0%) twins. The prevalence of major congenital malformations was 2.7% for MZ twins, 1.0% for DZ twins, and 0.6% for singletons. The concordance rate of major congenital malformations was 18% for MZ twins, but no DZ pair was concordant in any major congenital malformation. The concordance rate of facial clefts was 29% for MZ twins. There were 2 sets of conjoined twins giving a prevalence rate of 2.7 per 100,000 deliveries. These findings showing the prevalence of perinatal mortality and major congenital malformation to be highest in MZ twins, intermediate in DZ twins and lowest in singletons, suggest the importance of intrauterine environments in the determination of perinatal mortality and congenital malformations.

Congenital Abnormalities↗
PubMed1992

Secular trend and associated factors of twinning in Taiwan.

Delivery records of public hospitals and local health centers were analyzed to investigate the secular trend of multiple births from 1955 to 1990 in Taiwan. Twinning rates decreased gradually from the late 1950s to 1973, slightly increased and remained stable from 1974 to 1980, and then increased strikingly from 1981 to 1990. During the study period, MZ rates were consistently higher than DZ rates except in 1986 when a higher DZ rate was observed. The highest MZ rate of 7.7 per 1,000 deliveries was observed in 1985, while the highest DZ rate of 4.6 per 1,000 deliveries was observed in 1986. The triplet incidence rate also declined from the early 1960s to 1973 and then increased markedly from 1974 to 1990. A case-control study including 482 MZ and 252 DZ twin pairs and 1,496 singletons was carried out in four teaching hospitals in Taipei City between October 1985 and June 1989 to examine factors related to twinning. The zygosity of twin pairs was determined by sex, placentation and red blood cell antigens. Multiple logistic regression analysis showed that the higher the maternal age, the lower the MZ and DZ rates, while the higher the parity, the higher the rates. There was no association of paternal age or of maternal educational level with twinning rates.

Adult↗
PubMed1992

Functional study of hepatitis delta virus large antigen in packaging and replication inhibition: role of the amino-terminal leucine zipper.

The large hepatitis delta antigen (HDAg) has been found to be essential for the assembly of the hepatitis delta virion. Furthermore, in a cotransfection experiment, the large HDAg itself, without the hepatitis delta virus (HDV) genome and small HDAg, could be packaged into hepatitis B surface antigen (HBsAg) particles. By deletion analysis, it was shown that the amino-terminal leucine zipper domain was dispensable for packaging. The large HDAg could also help in copackaging of the small HDAg into HBsAg particles without the need for HDV RNA. This process was probably mediated through direct interaction of the two HDAgs as a mutated large HDAg whose leucine zipper domain was deleted such that it could not help in copackaging of the small HDAg. This mutated large HDAg did not suppress HDV replication, suggesting that this effect is probably also via protein interaction. These results indicated that functional domains of the large HDAg responsible for packaging with HBsAg particles and for the trans-negative effect on HDV replication can be separated.

Antigens, Viral↗
PubMed1992

Study of the changes in collagen of the tunica albuginea in venogenic impotence and Peyronie's disease.

We identified the collagen type and content of the tunica albuginea in Peyronie's disease and venogenic impotence compared with the tunica albuginea from the donor of the renal transplant and patients with penile injury. Type III collagen was detected obviously in Peyronie's plaque and was also present in venogenic impotence. It can be hardly found in normal controls. The ratios of type III to type I collagen were significantly higher in Peyronie's plaque while there was a moderate increase in venogenic impotence. The scarcity of type V collagen was noted in human tunica albuginea. The decreased percentage of glycine and alanine in Peyronie's disease and venogenic impotence implied the abnormal composition of collagen or presence of noncollagen protein. The results suggest the biochemical aberration of the tunica albuginea might interfere with the normal function of the penile drainage system.

Amino Acids↗
PubMed1992

A comparative study with intracavernous injection of prostaglandin E1 versus papaverine for the diagnostic assessment of erectile impotence.

The intracavernous injection of vasoactive drugs is a valuable diagnostic aid and an important tool for the treatment of erectile failure. A comparative study with intracavernous injection of prostaglandin E1 (PGE1) and papaverine was performed in 60 patients with impotence. We evaluated the efficiency and side effects of both agents. The overall positive response rate was 85.0% in the PGE1 group and 65.0% in the papaverine group which suggests PGE1 has a stronger vascular effect. The mean onset of maximal erection was after 9.6 minutes in the PGE1 group and after 6.5 minutes in the papaverine group. The mean maintenance of erection was for 53.2 minutes in the PGE1 group and for 38.6 minutes in the papaverine group. There were no systemic side effects of either agent. Three instances of injection pain and 2 of burning sensation in the penis were noted in the PGE1 group, while in the papaverine group, there were 21 reports of injection pain, 4 of prolonged erection and 2 of burning sensation in the penis. These results suggest that PGE1 is a more desirable vasoactive alternative for the diagnosis of impotence.

Adult↗
PubMed1992

Nonfunctioning pituitary adenoma.

A total of 14 patients (8 males and 6 females) with nonfunctional pituitary adenomas were diagnosed and underwent surgical intervention at the Kaohsiung Medical College Hospital between 1986 and 1991. Their ages ranged from 20 to 68 years with an average of 49.7 years. Eight adenomas were composed of small polygonal cells with chromophobic cytoplasm and other six were of large cells with pale eosinophilic granular cytoplasm. Immunohistochemical staining had negative staining of prolactin (PRL), growth hormone (GH), adrenal corticotropic hormone (ACTH) and thyroid stimulating hormone (TSH) in all cases, but scattered or wide spread cells containing alpha-subunit of glycoprotein hormones were found in 6 cases. Hormonal hypersecretion was absent in all of the clinical and biological pictures, as was reactivity to immunohistochemical examination. There were either very few signs of secretory activity, or none at all. CT and MRI scanning revealed 13 macroadenomas (92.9%) and one microadenoma. In seven cases, local invasion or suprasellar extension resulted in decreased visual acuity, but the most common clinical symptoms were progressive headache (78.6%), and visual disturbance (50.0%). After surgical intervention, symptoms disappeared in 74.2% of the patients.

Adenoma↗
PubMed1992

Occurrence of nasopharyngeal carcinoma in aboriginals of Taiwan: report of 14 cases.

The authors describe the rare occurrence of nasopharyngeal carcinoma (NPC) in 14 aboriginals of Taiwan (ABT), a minor ethnic group now accounting for less than 2% of the total population in Taiwan. The observation is epidemiologically unusual, representing a low-risk ethnic group in an NPC prevalent area. With regard to patient characteristics, symptomatology and pathology, we have not found any appreciable differences in reports from other geographic areas. Serological profiles of antiEBV-VCA (Epstein-Barr virus, viral capsid antigen) antibody in 7/9 patients available for review of IgA and 5/7 patients available for review of IgG were found significantly elevated, ranging respectively from 1:40-640/1:160-1280. Interestingly, 12 of the 14 patients were found to be exclusively from the Paiwan tribe residing in Pintung, a district in southern Taiwan. Since the exact prevalence of NPC in this minority remains unknown, it is not clear whether the apparent preponderance is real or merely causal due in part to geographic bias. To a lesser extent, however, our observations indicate that NPC is not an uncommon malignancy in Paiwan aboriginals of southern Taiwan.

Adult↗
PubMed1992

Pituitary oncocytoma: three cases report.

Three out of 102 pituitary adenoma patients, including 2 males and one female, had their pituitary tumors diagnosed as "oncocytomas" and underwent transsphenoidal adenomectomy. The tumors were confirmed as "pituitary oncocytomas" by both immunohistochemical staining and electron microscopy. They had poorly developed subcellular organelles and were markedly hyperplastic and pleomorphic, with swollen mitochondria in the cytoplasm and scattered secretory granules along the cell membranes. Postoperative follow-up revealed that visual acuity gradually improved in all the patients, and no tumor recurrence was found. The accurate preoperative diagnosis of pituitary oncocytomas relies on endocrinological, neuroradiological clinical evaluation, and the management of this disease must be surgery with postoperative radiotherapy.

Adenoma↗
PubMed1991

The large form of hepatitis delta antigen is crucial for assembly of hepatitis delta virus.

The virions of hepatitis delta virus (HDV) contain two species of HDV-specific protein, a large and a small form of hepatitis delta antigen (HDAg). We examined the role of individual HDAgs in virion assembly in cotransfection experiments. First, we constructed a replication-competent HDV mutant expressing only the small HDAg. When cotransfected with a plasmid expressing hepatitis B virus surface antigens to the HuH-7 cells, the mutant did not produce HDV virions, whereas the wild-type HDV clone did. Therefore, though the small HDAg is important for viral replication and is incorporated into the virus, the small-form delta antigen by itself is insufficient for virion formation. When the system was co-transfected with an additional plasmid providing the large HDAg, the HDV virion was then recovered. There was also evidence suggesting that the large HDAg could be copackaged into the HBsAg particles, without the presence of the HDV genome and the small HDAg. The results indicate a crucial role of the large HDAg in HDV assembly.

Antigens, Viral↗
PubMed1991

Monoclonal anti-idiotypic antibodies to platelet activating factor (PAF) and their interaction with PAF receptors.

Monoclonal anti-idiotypic antibodies (3C3F3E4 and 10D3F8H7) that interact with platelet activating factor (PAF) receptors were generated using an auto-anti-idiotypic approach by immunizing mice with an aldehydic analog of PAF coupled to bovine thyroglobulin. The resulting hybridomas were screened for anti-idiotypic antibody (anti-anti-PAF) with F(ab')2 fragments of affinity-purified polyclonal rabbit anti-PAF antibody. These antibodies displayed internal image properties of PAF and were considered as Ab2 beta according to the following criteria: (a) they bound to F(ab')2 fragments of the affinity-purified rabbit polyclonal anti-PAF antibody that had high affinity for PAF; (b) they inhibited [3H]PAF binding to rabbit polyclonal anti-PAF antibody and its F(ab')2 fragment in a concentration-dependent manner; (c) they displaced [3H]PAF from the anti-PAF antibody/[3H]PAF complex specifically; (d) they inhibited [3H]PAF binding to PAF receptors on rabbit platelet membranes dose dependently; (e) they displaced [3H]PAF from the [3H]PAF/PAF receptor complex specifically; and (f) they stimulated rabbit platelets to aggregate, and this aggregation could be inhibited or totally blocked by specific PAF receptor antagonists WEB 2086 and SRI 63-441. All of the above are consistent with the first successful production of monoclonal antibodies that mimic PAF and interact specifically with the PAF binding domain of PAF receptors on rabbit platelet membranes.

Animals↗
PubMed1991

Thyroid hormone changes after cardiovascular surgery and clinical implications.

Alterations in serum concentrations of total triiodothyronine (TT3), total thyroxine (TT4), and thyroid-stimulating hormone (TSH) frequently occur in patients with nonthyroidal illnesses. These changes correlate with the severity of the illness and the prognosis. In this study, 44 patients undergoing a cardiovascular operation had significant declines in serum TT3 and TT4 levels during cardiopulmonary bypass and thereafter. Serum TT3 and TT4 concentrations reached their nadir at 30 minutes after the start of cardiopulmonary bypass with values (mean +/- standard error of the mean) of 0.77 +/- 0.12 nmol/L (50.4 +/- 7.6 ng/dL) and 68.2 +/- 10.2 nmol/L (5.30 +/- 0.79 micrograms/dL), respectively. The mean serum concentrations of TSH and TT4 returned to preoperative levels by the sixth day after operation, whereas TT3 levels remained low throughout the study period. The patients whose recovery was uneventful had higher serum TT3, TT4, and TSH levels than those who had complications or died. The trend toward recovery was initiated by a sharp increase in the serum TSH level and increases in serum TT3 and TT4 concentrations on the fourth day after operation. Patients with complications either did not show these changes or had only a transient increase in TT3 and TT4 levels. All of the patients had a normal serum free T4 level before anesthesia. Those with an uneventful recovery had a higher serum free T4 level on the sixth day after operation than those with complications. Two patients in the latter group had serum free T4 levels less than normal at that time.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Modulatory effect of crocetin on aflatoxin B1 cytotoxicity and DNA adduct formation in C3H10T1/2 fibroblast cell.

Crocetin is a carotenoid isolated from the seeds of Cape jasmine (Gardenia jasminoides). The cytotoxicity and DNA-adduct formation of rat microsome-activated aflatoxin B1 (AFB1) in the C3H10T1/2 cells were significantly inhibited by pretreatment of crocetin. Most significant inhibition was found at the time of 9 h after crocetin pretreatment. Under these experimental conditions, consistent elevation in the cytosolic glutathione (GSH) levels and the activities of GSH S-transferase (GST) and GSH-peroxidase (GSH-Px) were observed. Crocetin treatment also resulted in a decrease in AFB1-DNA adduct formation in vitro, while no effect of crocetin on the formation of AFB1-8,9-oxide in vitro system was detected as measured by the Trisdiol method. From these results, we suggested that the protective effect of crocetin on the AFB1-cytotoxicity in C3H10T1/2 cells might be due to the cellular defense mechanisms that elevated the cytosol GSH and the activities of GST and GSH-Px.

Aflatoxin B1↗
PubMed1991

Suppressive effect of geniposide on the hepatotoxicity and hepatic DNA binding of aflatoxin B1 in rats.

The effects of geniposide pretreatment on both hepatic aflatoxin B1 (AFB1)-DNA binding and AFB1 hepatotoxicity in rats has been examined. For these studies, male Sprague-Dawley rats were treated with AFB1 (2 mg/kg) by i.p. administration, and the different degrees of hepatic damage were revealed by the elevations of levels of serum marker enzymes such as aspartate aminotransferase (AST), alanine amino-transferase (ALT) and gamma-glutamyltranspeptidase (gamma-GT). After pretreatment of animals with geniposide (10 mg/kg) daily for 3 consecutive days, the enzyme elevations were significantly suppressed. This suggested that the geniposide possessed chemopreventive effects on the early acute hepatic damage induced by AFB1. Under these experimental conditions, consistent elevation of the activities of glutathione S-transferase (GST) and gamma-glutamylcysteine synthetase but not glutathione peroxidase (GSH-Px) and gamma-glutamyltranspeptidase were observed. Treatment of rats with geniposide significantly lowered hepatic GSH and GSSG levels, but the ratio of GSH to GSSG was not changed. Geniposide treatment also decreased AFB1-DNA adduct formation in AFB1-treated animals. From these results, we suggest that the protective effect of geniposide on AFB1 hepatotoxicity in rats might be due to the hepatic tissues' defense mechanisms that involve the enhanced GST activity for AFB1 detoxication and induction gamma-glutamylcysteine synthetase for GSH biosynthesis.

Aflatoxin B1↗