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Biomedical subjects

S W Wang

Publications and source records attributed to S W 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

cDNA surveying of specific tissue expression of human chromosome 19 sequences.

cDNA surveying is a straightforward approach for identifying sequences in genomic clones expressed in specific tissues. It has been applied to a subchromosomal region of human chromosome 19 (19q13.2-q13.4), a region that contains several known expressed sequences including the locus for myotonic dystrophy (DM). Genomic clones were selected from this region by probing a human placental cosmid library with a chromosome 19q-specific minisatellite sequence, or human genomic clones were isolated from a cosmid library constructed from a human chromosome 19q13.2-q13.3 hamster hybrid cell line using human repetitive DNA as probe. Pooled cDNAs synthesized from RNA of specific tissues characteristically affected in DM were depleted in repetitive sequences and used as hybridization probes against gridded cosmid arrays. DNA from the cDNA-positive cosmid clones was transferred to nylon filters and reprobed with cDNAs to identify restriction fragments that were expressed in these tissues. Hybridizing restriction fragments were subcloned, sequenced, and demonstrated to be nonrepetitive. Primer pairs complementary to subcloned sequences were constructed and used for PCR amplification of cDNA synthesized from RNA of tissues affected in myotonic dystrophy. PCR products were sequenced to verify the identity of expressed genomic DNA and its corresponding cDNA.

Animals↗
PubMed1992

Purification of core-binding factor, a protein that binds the conserved core site in murine leukemia virus enhancers.

The Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major genetic determinant of the thymic disease specificity of the Moloney virus genetically maps to two protein binding sites in the Moloney virus enhancer, the leukemia virus factor b site and the adjacent core site. Point mutations introduced into either of these sites significantly shifts the disease specificity of the Moloney virus from thymic leukemia to erythroleukemia (N. A. Speck, B. Renjifo, E. Golemis, T. Frederickson, J. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We have purified several polypeptides that bind to the core site in the Moloney virus enhancer. These proteins were purified from calf thymus nuclear extracts by selective pH denaturation, followed by chromatography on heparin-Sepharose, nonspecific double-stranded DNA-cellulose, and core oligonucleotide-coupled affinity columns. We have achieved greater than 13,000-fold purification of the core-binding factors (CBFs), with an overall yield of approximately 19%. Analysis of purified protein fractions by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis reveals more than 10 polypeptides. Each of the polypeptides was recovered from an SDS-polyacrylamide gel, and those in the molecular size range of 19 to 35 kDa were demonstrated to have core-binding activity. The purified CBFs were shown by DNase I footprint analyses to bind the core site in the Moloney virus enhancer specifically, and also to core motifs in the enhancers from a simian immunodeficiency virus, the immunoglobulin mu chain, and T-cell receptor gamma-chain genes.

Base Sequence↗
PubMed1992

Prediction of life-threatening arrhythmia in patients after myocardial infarction by late potentials, ejection fraction and Holter monitoring.

In order to compare the prognostic significance of late potentials (LPs) on signal-averaged electrocardiogram (SA-ECG), left ventricular ejection fraction (EF) and 24-hour Holter monitoring (HM) following myocardial infarction, a prospective study on 60 patients (age 61.7 +/- 8.02 years old) just after acute myocardial infarction (AMI) was done. LPs, EF and HM were performed in all patients. Coronary arteriography had been done in 25 patients. The results showed that LPs were associated with a slightly higher incidence of life-threatening arrhythmia (34.8%) than HM (28.6%) and EF (25%). During the follow-up period (10 +/- 6 months), 9 patients had serious ventricular arrhythmic events, among whom 3 had sudden death due to ventricular fibrillation. The event rate in patients with abnormal LPs was higher than in patients with normal LPs (p = 0.01, odds ratio = 19.2). The study showed that there was no correlation between abnormal LPs and sex, age, number of narrowed coronary arteries, ventricular aneurysm, location of myocardial infarction, or EF alone. But there was a correlation between abnormal LPs and high grade ventricular ectopic activity detected by HM (r = 0.62899, p = 0.024). In addition, the combination of abnormal values of LPs, EF and HM could predict sustained ventricular tachycardia or sudden death in the first year after myocardial infarction with very high sensitivity (100%) as well as high specificity (p = 0.0009, odds ratio = 19).

Adult↗
PubMed1992

[A study on knee joint geometry in Chinese: significance to prosthesis design].

This study for the first time provided the geometric parameters of knee joints in Chinese, which are indispensable for the design of domestic knee prosthesis. Thirty five items, including linear, radial and angular measurements, were taken from 105 cadaver knees and knee X-ray films of 100 subjects. The method and calculation for proper correction of the X-ray image magnification and joint cartilage space was established. Correlation between the X-ray correction coefficients and the body weight was found to exist, and it formed the basis for individualized correction of X ray measurements. Statistical analysis revealed that most of the linear and radial measurements were highly related while the angular measurements were independent of others. Principal component analysis showed that the width of femoral condyle might be taken as the leading index in determining the dimension of the knee, and regression functions were established. Multivariate discriminate functions could aid the selection of knee prosthesis.

Adolescent↗
PubMed1992

A study of Chinese knee joint geometry for prosthesis design.

This study for the first time provides the geometric parameters of the knee joint of Chinese, which is indispensible to the design of knee prosthesis used for compatriotic patients. Thirty-five items, including linear, radial and angular measurements, were taken from 105 cadaveric knees and knee X-ray films of 1,100 subjects. The method and calculation for proper correction of the X-ray image magnification and joint cartilage space was established. Correlation was found to exist between the X-ray correction coefficients and the body weight, which formed the basis for individualized correction of X-ray measurements. Statistical analysis revealed that most of the linear and radial measurements were highly related while the angular measurements were independent of others. Principal component analysis showed that the width of femoral condyle might be taken as the leading index in determining the dimension of the knee, and regression functions were established to supply the serial parameters for prosthetic design. Multivariate discriminate functions could aid the selection of knee prosthesis.

Anthropometry↗
PubMed1992

[Synthesis of molluscacidal synergists].

Chemical molluscicides are useful in schistosomiasis control. A synergist can potentiate the efficacy and reduce the dosage of a molluscicide, thus decreasing the toxicity and environmental pollution. In order to search for potential molluscicidal synergists, 13 compounds of O,O-dialkyl-O-(2-substituted-3-benzofurylacetonitrile-alpha-oxi mino)phosphate or thiophosphate (VI1-13) and 2 compounds of O,O-dialkyl-O-(2-thienylacetonitrile-alpha-oximino)phosphate (X14,15) were prepared. Preliminary test demonstrated that compound X15 had strong synergic effect with sodium pentachlorophenol in combating mollusks. Compounds X14 and VI1,2,3,6,8,10,12,13, also showed some molluscicidal synergistic activity.

Animals↗
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↗
PubMed1990

Effect of ethanol on hepatotoxicity and hepatic DNA-binding of aflatoxin B1 in rats.

The hepatocarcinogen aflatoxin B1 is converted to reactive metabolites that bind covalently to cellular macromolecules. These metabolites may also react with glutathione, resulting in the formation of glutathione conjugates and detoxication of the reactive metabolite. When rats were pretreated with ethanol by gastric intubation at a dose of 100 mmol/kg, 6 hr (the time of maximal GSH depletion) before the administration of aflatoxin B1, the covalent binding of 8,9-epoxide-aflatoxin B1 to DNA in vivo was increased by 47% and the hepatotoxicity was also potentiated. However, the covalent binding was not increased by pretreatment with ethanol 18 hr (time with approximately normal GSH levels) before administration of the toxin, and no potentiation of hepatotoxicity was observed. Pretreatment with a non-toxic dose of ethanol had no effects on the activity of glutathione S-transferase and glutathione peroxidase. These results suggest that the depletion of GSH and the increased formation of DNA-adduct from the liver constitute an important mechanism for the potentiation of aflatoxin B1-induced hepatotoxicity by ethanol.

Aflatoxin B1↗
PubMed1990

Study on BcII/St14 RFLPs in Chinese for DNA diagnosis for hemophilia A.

The BcII polymorphism within DXS52 (St14) was reported. It was composed of 4 allelic fragments, 4.0 kb, 3.3 kb, 3.0 kb and 2.3 kb. The frequency of these fragment were 0.09, 0.12, 0.44 and 0.35 respectively in the Chinese. The polymorphism provided the PIC of 0.66. DNA analysis of families with hemophilia A showed that the confidence of the RFLPs was the same as the TaqI/St14 RFLPs and for carrier detection the former is much better than that of the TaqI/St14 RFLPs.

China↗
PubMed1990

A clinicopathologic comparison of acute myocardial infarction in the elderly Chinese and American.

A prospective study was done on 110 patients, 55 Chinese and 55 American elderly who had clinically proved acute myocardial infarction with histologic confirmation. The Chinese patients were much more likely to have typical pain than the American (65.4% vs 49.0%). The incidence of painlessness was only 18.1% vs 36.3%. The difference has statistical significance (P less than 0.05). Cardiac failure, shock, pulmonary infection as a major complication had no statistical significance, but the incidence of cardiac rupture group was 29.0% vs 10.9%. Ventricular fibrillation incidence was 18.1% in the Chinese vs 45.4% in the American. The incidence of recent occlusive coronary thrombi, hemorrhage and rupture of plague in coronary arteries had significant statistical difference. The incidence of triple, double and single vessel diseases were 41.8%, 29.0% and 27.2% in the Chinese group vs 36.3%, 27.2% and 25.4% in the American respectively.

Aged↗
PubMed1990

Clinical features of multiple organ failure in the elderly.

Multiple organ failure (MOF) in the elderly is a new syndrome evolved from multiple organ chronic diseases on the basis of multiple organ dysfunction in the aged. Its characteristics are clinically different from those of MOF due to serious trauma. 122 cases of MOF were analysed retrospectively and their clinical features discussed. MOF with a long course is the natural presentation in many of the elderly before death. Its main precipitating factors are pulmonary infection, metastatic carcinoma, cardiac attack, etc. The sequence of a failure in organs is heart, lung, kidney, liver, etc. The mortality is similar to that of MOF due to trauma. However, those suffering from 4-organ failure can still survive, and instead, the renal failure can be mostly fatal. More attention should be paid to the prevention of MOF in the elderly so as to shorten its developing course.

Aged↗
PubMed1990

[Inherited relationship of levels of serum lipid and lipoprotein in nuclear families in patients with arteriosclerotic stroke].

This report presents the study on inherited relationship of levels of lipids and lipoprotein in 20 nuclear families of patients with arteriosclerotic stroke through application of analysis of correlation and regression. The results showed that the levels of serum lipids between spouses had little or nearly no correlation; and that between mid-parent and their children had positive or significant positive correlation, and so did that between siblings. It seems that the genetic factor have an important influence on levels of serum lipids in members of nuclear families of patients with arteriosclerotic stroke.

Cholesterol↗
PubMed1989

The efficacy of triclabendazole (Fasinex) against immature and adult Fasciola hepatica in experimentally infected cattle.

Eighteen Chinese cattle were experimentally infected with metacercariae of Fasciola hepatica and randomly assigned to 6 groups. Five groups of cattle were treated with a single oral dose of triclabendazole at a dose rate of 12 mg kg-1. At necropsy, the reduction in fluke burden compared with the untreated group was 85, 99.6, 99.8, 100 and 100% for cattle treated 2, 6, 8, 12 and 16 weeks after infection, respectively. Data are also presented on body weight changes during the experimental period and on serum gamma-GT activity in cattle from selected groups. Triclabendazole is considered to be safer and more efficacious than currently available fasciolicides in China.

Animals↗
PubMed1989

[Biotinylated Y chromosome specific probe for human sexing].

Human chromosome DNA from WBC or fetus chorion samples were digested with Hae III and hybridized with biotinylated Y chromosome specific probe by Southern blotting, and hybridization signals were developed by the ABC (Avidin-biotin-alkaline phosphatase complex) system. The hybridization signal for 0.1 microgram of male DNA could be detected clearly, while the signal for even 5 micrograms of female DNA could not. Parallel tests showed that the sexing results using 32P-labeled and biotinylated Y probe were identical. This suggests that the biotinylated Y probe can be applied to the determination of X-linked genetic diseases and sex abnormality, forensic analysis, sex determination of sportsmen and women, heterosexual transplantation of bone marrow, etc. It could become a convenient means for genetic diagnosis.

Affinity Labels↗