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Biomedical subjects

W L Wang

Publications and source records attributed to W L Wang.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of transient expression of the oestrogen receptor on constitutive and inducible CYP1A1 in Hs578T human breast cancer cells.

Hs578T human breast cancer cells are an oestrogen receptor (ER)-negative cell line. Treatment of these cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in formation of a 6.9 S nuclear aryl hydrocarbon (Ah) receptor complex, which bound to a [32P]dioxin-responsive element in a gel electrophoretic mobility shift assay. However, TCDD does not induce CYP1A1 gene expression or chloramphenicol acetyl transferase (CAT) activity in cells transiently transfected with pRNH11c or pMCAT5.12, which are Ah-responsive plasmids derived from the 5'-flanking region of the human and murine CYP1A1 genes respectively. Restoration of Ah responsiveness was investigated by co-transfecting Hs578T cells with pRNH11c or pMCAT5.12 and plasmids that express the ER (hER), Ah receptor (AhR) and AhR nuclear translocator (Arnt) proteins. ER expression resulted in significantly increased basal CAT activity; however, TCDD did not induce CAT activity in the transiently transfected cells. Expression of the AhR or Arnt proteins did not alter basal or inducible CAT activity. Expression of N- or C-terminal truncated ER in Hs578T resulted in differential regulation of Ah responsiveness. In Hs578T cells transiently expressing the ER, which contains C-terminal deletions (amino acids 282-595), basal CAT activity was also increased; however, Ah responsiveness was not restored. In contrast, transient expression of N-terminal-deleted (amino acids 1-178) ER resulted in a marked decrease in basal CAT activity but a restoration of Ah responsiveness. These results suggest that basal and inducible CAT activity in Hs578T cells transiently transfected with pRNH11c is modulated differentially by ER domains that are present in the N- and C-terminal regions of the ER.

Base Sequence↗
PubMed1996

Apoptosis and expression of Bcl-2 after compression trauma to rat spinal cord.

We have evaluated by in situ nick-end labeling the presence of apoptotic cells in the spinal cord of rats with compression injury at the level of Th8-9 of mild, moderate, and severe degrees resulting in no neurologic deficit, reversible paraparesis, and paraplegia, respectively. Rats with compression injury surviving 4 or 9 days showed apoptotic glial cells in the longitudinal tracts of the Th8-9, the cranial Th7, and the caudal Th10 segments. The apoptotic cells were most frequently observed in Th7. They did not express glial fibrillar acidic protein (GFAP) and their morphology was compatible with that of oligodendrocytes. Neurons of the gray matter did not present signs of apoptosis. In addition, we studied the immunohistochemical expression of Bcl-2, an endogenous inhibitor of apoptosis. Compression induced Bcl-2 immunoreactivity in axons of the long tracts, particularly after moderate and severe compression and 1-day survival. Neurons of dorsal root ganglia were immunoreactive but the neurons of the spinal cord were unstained. The accumulation, presumably caused by arrested axonal transport in sensory pathways, was absent in rats surviving 9 days. In conclusion, compression trauma to rat spinal cord induces signs of apoptosis in glial cells, presumably oligodendrocytes of the long tracts. This may induce delayed myelin degeneration after trauma to the spinal cord. Bcl-2 does not seem to be upregulated in oligodendrocytes.

Animals↗
PubMed1995

Testing human hair for drugs of abuse. IV. Environmental cocaine contamination and washing effects.

Active cocaine use results in sequestration of parent drug in hair. In addition, hair has unique physicochemical properties that permit absorption of cocaine from the environment. When hair is tested for evidence of cocaine, it is important to consider whether the positive test resulted from active drug use or environmental contamination. In a series of laboratory experiments, it was found that exposure of 'cut' hair to cocaine vapor ('crack' smoke) and to aqueous solutions of cocaine hydrochloride resulted in significant contamination of hair samples. Similar results were obtained with two subjects who were exposed to cocaine vapor in an unventilated room. The amount of contamination adsorbed by hair depended upon both time and extent of exposure. Washing the hair samples with methanol removed > 70% of the cocaine contaminant after cocaine vapor exposure, but was less effective (< 50%) following contamination with aqueous cocaine. Shampoo treatment cycles (overnight soaking) progressively removed increasing amounts of cocaine from the contaminated hair, but residual cocaine remained after 10 cycles. Studies were also performed to determine the usefulness of benzoylecgonine as a marker of active cocaine administration. Small amounts of benzoylecgonine (ca. 1 ng/mg) were formed in hair as a result of environmental contamination with cocaine. Also, it was found that benzoylecgonine could be adsorbed from illicit cocaine contaminated with benzoylecgonine. It was concluded that positive hair test results should be interpreted cautiously due to the possibility of environmental contamination from cocaine and related constituents.

Air Pollution↗
PubMed1994

Simultaneous assay of cocaine, heroin and metabolites in hair, plasma, saliva and urine by gas chromatography-mass spectrometry.

As part of an ongoing research program on the development of drug detection methodology, we developed an assay for the simultaneous measurement of cocaine, heroin and metabolites in plasma, saliva, urine and hair by solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). The analytes that could be measured by this assay were the following: anhydroecgonine methyl ester; ecgonine methyl ester;. ecgonine ethyl ester; cocaine; cocaethylene; benzoylecgonine; cocaethylene; norcocaethylene; benzoylnorecgonine; codeine; morphine; norcodeine; 6-acetylmorphine; normorphine; and heroin. Liquid specimens were diluted, filtered and then extracted by SPE. Additional handling steps were necessary for the analysis of hair samples. An initial wash procedure was utilized to remove surface contaminants. Washed hair samples were extracted with methanol overnight at 40 degrees C. Both wash and extract fractions were collected, evaporated and purified by SPE. All extracts were evaporated, derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS) and analyzed by GC-MS. The limit of detection (LOD) for cocaine, heroin and metabolites in biological specimens was approximately 1 ng/ml with the exception of norcodeine, normorphine and benzoylnorecgonine (LOD = 5 ng/ml). The LOD for cocaine, heroin and metabolites in hair was approximately 0.1 ng/mg of hair with the exception of norcodeine (LOD = 0.3 ng/mg) and normorphine and benzoylnorecgonine (LOD = 0.5 ng/mg). Coefficients of variation ranged from 3 to 26.5% in the hair assay. This assay has been successfully utilized in research on the disposition of cocaine, heroin and metabolites in hair, plasma, saliva and urine and in treatment studies.

Cocaine↗
PubMed1994

Immunohistochemical demonstration of CCAAT/enhancer binding protein (C/EBP) in human liver tissues of various origin.

C/EBP is a sequence-specific DNA-binding protein. In order to identify its distribution and localization, immunohistochemical technique (ABC method) was done using anti-C/EBP polypeptide antibodies 1103#, 425# in liver specimens from 20 normal adults, 5 neonates, 6 patients with hepatitis, 25 with liver cirrhosis, 80 with hepatocellular carcinoma (40 cases were associated with surrounding nontumorous tissues) and 26 patients with cholangiocarcinoma (15 cases were associated with surrounding nontumorous tissues). The results showed that C/EBP was diffusely distributed in nuclei and cytoplasm of differentiated liver cells and very low or undetectable in liver cancer cells. The manifestation of C/EBP correlated with degree of differentiation of tumour cells, and was obviously weaker than that in surrounding nontumorous tissues. C/EBP positive staining has also been found in regenerating epithelial cells of bile ductules. The results suggested that C/EBP should play an important role in establishing and maintaining the differentiation of liver cells.

CCAAT-Enhancer-Binding Proteins↗
PubMed1994

[Localization of apoptosis-antagonizing bcl-2 translated product in Hodgkin's disease].

We applied more sensitive immunohistochemical method, i.e. multilayered PAP, to investigate the expression and distribution of apoptosis-antagonizing gene bcl-2 in Hodgkin's disease (HD), bcl-2-positive Reed-Sternberg (RS) cells were found in 7 of 21 (33%) of HD, and 2 of 7 (mixed cellularity) accompanied by a lot of reactive lymphoid follicles, the germinal centers of which were also positive for bcl-2. In contrast, in 4 cases of inflammatory lymphoid follicular hyperplasia as positive controls, the mantle zones rich in long-lived B cells were strongly positive stained with bcl-2 antibody, whereas germinal centers were negative. Thus, our data indicate that overexpressed bcl-2 gene-mediated apoptosis impairment is strongly associated with pathogenesis of HD.

Apoptosis↗
PubMed1994

[In situ PCR-gene hybridization method for detecting mycobacterium tuberculosis in tissue specimens].

The authors combined the technique of polymerase chain reaction (PCR) with hybridization in situ, and find the method is better, quicker and more sensitive for detecting a trace of bacterial DNA, especially for observing the relation between the lesion and the peripheral tissue, the method is more simple and no radioactive pollution. It seems to be suitable for detection on samples from autopsy, biopsy and smears. We suppose the method might have a prospect for clinical diagnosis.

Base Sequence↗
PubMed1993

Biosynthesis of ecdysteroid hormones by crustacean Y-organs: conversion of cholesterol to 7-dehydrocholesterol is suppressed by a steroid 5 alpha-reductase inhibitor.

A pair of glands (Y-organs) in crustaceans synthesize and secrete ecdysteroid hormones; the obligate precursor for synthesis is circulating cholesterol. Ecdysteroid output by the Y-organs is regulated negatively by an eyestalk neurosecretory peptide, molt-inhibiting hormone (MIH). The question was addressed, does MIH suppress ecdysteroid synthesis by decreasing cholesterol supply (uptake) or its utilization or both? Experiments were conducted with Y-organs in vitro from the crab, Menippe mercenaria, in the presence of labeled cholesterol, with or without the steroid 5 alpha-reductase inhibitor, L-645390 (Merck). Other experiments superimposed the presence or absence of eyestalk extract containing MIH activity. L-645390 greatly depressed incorporation of cholesterol into an early intermediate, 7-dehydrocholesterol and into secreted ecdysteroids. At the same time, cholesterol accumulated in the Y-organs, to levels significantly higher than in untreated controls. MIH alone depressed both cholesterol uptake and incorporation. MIH together with L-645390 produced the greatest depression of cholesterol incorporation while also preventing the cholesterol accumulation seen with L-645390 alone. These results indicate that cholesterol uptake and its metabolic utilization in Y-organs are separable events representing separate sites of regulation by MIH.

5-alpha Reductase Inhibitors↗
PubMed1993

Immunoassay evidence for fentanyl in hair of surgery patients.

Head hair samples obtained from surgery patients who received fentanyl during anesthesia were analyzed by immunoassay for the presence of fentanyl. Thirteen hair samples were collected from patients following intravenous administration of 1-6 mg of fentanyl. Additional hair samples were collected following the administration of 0.18 and 0.38 mg of sufentanil to 2 patients. The elapsed time after drug administration for all patients ranged from 7 to 273 days. Twenty control hair samples also were collected from staff members who reported no surgery or anesthesia during the previous year. All samples were initially washed with methanol, followed by extraction with methanol and reconstitution in citrate buffer. Analysis of wash and extract fractions was performed by radioimmunoassay (Coat-A-Count Fentanyl assay). Segmental analysis was performed on the surgery patients' hair samples. Eight of the fentanyl patients' hair samples contained fentanyl concentrations (equivalents) of 0.13-0.48 ng/10 mg of hair in the 'root' end. Fentanyl concentrations in the 'tip' segment were lower than those found in the 'root' segment with the exception of 1 subject whose hair sample had been collected only 7 days after surgery. The remaining 5 patients had fentanyl concentrations similar to those determined for the control subjects hair samples (0-0.08 ng/10 mg, n = 19). No correlation between hair fentanyl concentration and administered dose was found for the 13 fentanyl subjects. Both sufentanil subjects' hair samples tested negative. One control subject who had experienced environmental exposure to fentanyl had a fentanyl concentration of 0.29 ng/10 mg in the extract and 0.63 ng/10 mg in the wash fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The occurrence of cocaine, heroin and metabolites in hair of drug abusers.

The analysis of hair for drugs of abuse reveals information regarding past drug exposure. We developed methods for washing, extraction and analysis of hair samples for cocaine, heroin and metabolites. Twenty paired head- and arm-hair samples, collected from known heroin/cocaine abusers, were analyzed with a new comprehensive GC/MS assay for cocaine, heroin and metabolites. Cocaine and 6-acetylmorphine (6-AM) were the major analytes present in both head- and arm-hair samples. Cocaine was detected in all head- and 17 arm-hair samples. The concentration of cocaine found was 4-760 ng/10 mg in head hair and 0-1090 ng/10 mg in arm hair. Less benzoylecgonine was present in a concentration range of 0-158 ng/10 mg of head hair and 0-125 ng/10 mg of arm hair. Heroin was found in only 2 head-hair samples, whereas 6-AM was present in 14 head and 6 arm-hair samples. The concentration of 6-AM was 0-8 ng/10 mg in head hair and 0-31 ng/10 mg in arm hair. Morphine was present in 3 head-hair samples in a range of 2-9 ng/10 mg and was not detected in arm-hair samples. When results were compared by groups (head hair versus arm hair, Caucasoid versus Africoid), only two significant differences were found. Cocaine concentrations in both head and arm hair were significantly (P < 0.05) higher in the Africoid group than in the Caucasoid group. The reasons for these differences were not readily apparent, but could have been due to differences in the level of cocaine use or to ethnic differences in the deposition of drug in hair.

Adult↗
PubMed1993

[Expression of five different antigens of HBV in human intrahepatic cholangiocarcinoma and cholangiohepatocarcinoma].

Surgical specimens of 20 cases of human intrahepatic cholangiocarcinoma (n = 12) and cholangiohepatocarcinoma (n = 8) were studied immunohistochemically by ABC technique for HBxAg, pre-S1 and pre-S2 and by PAP method for HBsAg and HBcAg. The neighboring liver tissues with chronic hepatitis or cirrhosis surrounding the tumor were also examined in 19 cases. Of the cancerous tissues, 15 were positive for HBxAg (75%), 8 positive for pre-S1 and pre-S2 (40%), respectively and 2 for HBsAg (10%). Sixteen of 19 liver tissues surrounding the tumor were also positive for HBxAg (84.2%), 9 for pre-S1 and pre-S2 each (47.4%), 6 for HBsAg and HBcAg each (31.6%). The results suggest that a close relationship exists between cholangiocarcinoma and cholangiohepatocarcinoma and hepatitis B virus infection. The HBxAg might play an important role in the pathogenesis of cholangiocarcinoma.

Bile Duct Neoplasms↗
PubMed1992

Formation of ecdysteroids by Y-organs of the crab, Menippe mercenaria. I. Biosynthesis of 7-dehydrocholesterol in vivo.

Y-organs of the xanthid crab, Menippe mercenaria, secrete ecdysteroid hormones in vitro, apparently both 3-dehydroecdysone and 25-deoxyecdysone. Studies were initiated on the biosynthetic path(s), in which cholesterol is converted to these ecdysteroids. Crabs were injected with [3H]cholesterol. Y-organs and hemolymph were removed 12 hr later and extracted directly and the extracts were analyzed by HPLC. Both polar and nonpolar sterols were surveyed. The only metabolite of cholesterol detectable in Y-organs was 7-dehydrocholesterol (identified by mass spectrometry). The total amount of 7-dehydrocholesterol and the amount that was labeled were generally greater than for cholesterol and were higher in Y-organs from de-eyestalked crabs than in those from intact crabs. Subcellular fractionation of the Y-organs showed that over 70% of total radioactivity was in cholesterol and 7-dehydrocholesterol of mitochondria and microsomes, distributed about equally between the two organellar fractions. In hemolymph, the only nonpolar sterols present were cholesterol and 7-dehydrocholesterol; the concentration ratio was 20:1. However, 7-dehydrocholesterol was not significantly labeled. Analyses of polar compounds revealed two prominent, uv-absorbing ecdysteroids which coeluted with the authentic standards, 3-dehydro-20-hydroxyecdysone and 25-deoxy-20-hydroxyecdysone (ponasterone A). The radioactivity profile showed, in addition, a third prominent peak that corresponded in retention time with 3-dehydroecdysone. These results indicate that the Y-organs in vivo form 7-dehydrocholesterol from cholesterol and convert the latter to secretion products without accumulation of other intermediates. At least two ecdysteroids are secreted and appear to be converted peripherally in this crab to their respective 20-hydroxy derivatives.

Animals↗
PubMed1992

[Adsorption in stratum corneum and percutaneous penetration of propranolol hydrochloride].

The sorption and rate of permeation of propranolol hydrochloride were measured as a function of drug concentration in the solution bathing rat skin in vitro. The sorption isotherm was nonlinear, and can be expressed in Langmuir form. The lag time and apparent permeability coefficient through intact skin decreased as the concentration of donor compartment increased, and those through stripped skin were not varied. These results indicate that an adsorption process existed when propranolol hydrochloride penetrated through the stratum corneum. Based on the adsorption--diffusion theory, a mathematical formula was developed for expressing the relationship between the concentration of drug and permeability coefficient through the skin quantitatively.

Animals↗
PubMed1992

[Expression and significance of Pre-S1 and Pre-S2 in human primary hepatic carcinoma (PHC)].

135 specimens of primary hepatic carcinoma (PHC) were formalin fixed and paraffin embedded and stained for Pre-S1, Pre-S2 and HBxAg by ABC method, for HBsAg and HBcAg by PAP method. The detection rates of Pre-S1 and Pre-S2 positive cases in cancerous tissues were 22.2% and 20.0%. The detection rates of Pre-S1 and Pre-S2 in non-cancerous liver tissues were 60.0% and 59.6%. The positive ratio of Pre-S1 and Pre-S2 in the same hepatoma was 16.3% and that in the same non-cancerous liver tissue was 55.6%. Among 135 cases of PHC, HBsAg, HBxAg and HBcAg positives in tumor tissues were 16.3%, 55.6% and 8.9%, respectively. Those in non-cancerous tissues were 59.6%, 78.8% and 24.2%. This study suggested that the detection rates of Pre-S1 and Pre-S2 positivity in hepatoma tissues were higher than those of HBsAg and HBcAg but lower than that of HBxAg. The frequency of positive Pre-S1 and Pre-S2 in non-cancerous liver tissues was similar to HBsAg, and slightly lower than that of HBxAg. S1 and S2 are considered new markers for HBV infection. Their antigens could play an important role in the pathogenesis of PHC.

Carcinoma, Hepatocellular↗
PubMed1992

[Immunohistochemical study on X antigen of HBV (HBxAg) in primary hepatic carcinoma].

Specimens of 110 cases of primary hepatic carcinoma were obtained from the pathological Laboratory of the First Teaching Hospital of the 4th Military Medical University, Xi'an. P. R. China. Sections from formalin-fixed and paraffin-embedded material were stained for HBxAg by ABC method and for HBsAg and HBcAg by PAP method. Among the 110 cases of primary hepatic carcinoma, 64 (58.2%) showed HBxAg-positive reaction in tumor tissue, and 63 (78.8%) of 80 cases of noncancerous surrounding hepatic tissue displayed HBxAg positivity. Among 64 HBxAg-positive cases in tumor tissue, 15 (23.4%) were associated with HBsAg and/or HBcAg and among 63 HBxAg-positive cases in non-tumor tissue, 45 (71.4%) were associated with HBsAg and/or HBcAg. These findings suggested a close relationship between primary hepatic carcinoma and HBV infection. The high detection rate of HBxAg indicates very active expression of the integrated HBV-DNA genome in the host cells. However, how does HBxAg act in pathogenesis of hepatocellular carcinoma remains to be further investigated.

Carcinoma, Hepatocellular↗
PubMed1991

Hepatitis B x antigen in hepatitis B virus carrier patients with liver cancer.

Formalin-fixed, paraffin-embedded specimens from 110 cases of primary hepatocellular carcinoma were stained for hepatitis B x antigen (HBxAg), hepatitis B surface antigen (HBsAg), and hepatitis B core antigen (HBcAg). Eighty-four % of these patients were HBxAg positive in their tumor cells. Among the 110 cases studied, 80 had adjacent nontumorous tissue in the same block, and 65 of these nontumorous liver tissues stained positive for HBxAg (81%). HBsAg was positive in 19% of cases within tumor tissue and 61% in surrounding nontumorous tissue. HBcAg was positive in 11% of cases within tumor tissue and 26% in surrounding nontumorous tissue. These findings show that HBxAg is a common marker in the liver of patients with hepatitis B virus (HBV)-associated primary hepatocellular carcinoma and that it is closely associated with tumor cells in these individuals. In addition, the finding of HBxAg in the absence of detectable HBsAg and HBcAg in the liver tissues of many HBsAg carriers suggests that HBxAg could be expressed independent of HBV replication and implies that the synthesis of this antigen may be directed from integrated HBV DNA templates. The finding of HBxAg in the nucleus of hepatocytes from primary hepatocellular carcinoma patients with dysplasia, combined with the known trans-activating properties of HBxAg, implies that HBxAg plays one or more important roles in hepatocarcinogenesis. The finding of HBxAg in bile duct epithelium and cholangiocarcinoma tissues is compatible with the hypothesis that HBV may contribute to this other primary tumor type in the liver. Together, these results further implicate HBxAg in the pathogenesis of primary liver cancers.

Carcinoma, Hepatocellular↗
PubMed1991

HBxAg in the liver from carrier patients with chronic hepatitis and cirrhosis.

Formalin-fixed, paraffin-embedded specimens from 110 cases of chronic hepatitis and 108 cases of cirrhosis were stained for HBxAg by the avidin-biotin complex technique using specific antisera made against full-length HBxAg polypeptide or derived synthetic peptides. These tissues were also stained for the HBsAg and HBcAg by the peroxidase-anti-peroxidase method. Among patients with chronic hepatitis, 86% were HBsAg positive in liver cells, 60% were surface antigen positive and 32% were core antigen positive. Among patients with cirrhosis, 97% were HBsAg positive in liver cells, 72% were surface antigen positive and 17% were positive for core antigen. Staining specificity was demonstrated, in part, by using preimmune sera in the place of primary antibody, by blocking of the primary antibody with the appropriate antigen before assay and by testing uninfected liver controls. The persistence and high frequency of HBxAg in liver cells from patients with chronic liver disease suggest that it may play one or more important roles in the pathogenesis of chronic infection. It is possible that detection of HBxAg in the liver could be an additional new diagnostic marker for hepatitis B virus infection. However, the function(s) of HBxAg in the pathogenesis of the chronic liver disease, if any, remains to be explained.

Carrier State↗