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Biomedical subjects

W G Zhang

Publications and source records attributed to W G Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1999

[The expression of E-cadherin-catenin complex in human salivary adenoid cystic carcinoma]

OBJECTIVE: The aim of this study was to investigate the expression of the E-cadherin-catenin(E-cad-cat) complex in human salivary adenoid cystic carcinoma(ACC) and determine the effects of E-cad-cat expression on tumor differentiation,metastasis and invasion as well as their clinical significance. METHODS:The expression of adhesion molecules,which included E-cadherin,alpha-catenin and beta-catenin,in 10 cases of normal salivary glands,50 cases of human salivary ACC was investigated by immunohistochemistry.RESULT:Co-expression of E-cadherin,alpha-catenin and beta-catenin was detected in 29(58%) of the 50 ACC specimens.Positive staining of E-cad-cat complex was detected in 7(39%) of the 18 ACC primary sites which had aggressive phenotype of nerve and vasculature.CONCLUSION:Strong positive signals of E-cad-cat complex were showed in normal salivary glands,and the down regulation expression was observed in ACC cases,The expression of E-cad-cat complex was associated with a more aggressive phenotype on nerve and vasculature.No association with various histopathologic subtypes was found;Down-regulation of E-cad-cat complex may be associated with canceration of normal salivary glands.

Journal Article↗
PubMed1999

[The expression of adhesion molecules in human salivary adenoid cystic carcinoma cell line]

OBJECTIVE:The aim of this study was to investigate the expression of the adhesion molecules in human salivary adenoid cystic carcinoma(ACC) cell lines (ACC-2 line and ACC-M strain) which had different metastatic ability.METHODS:The expression of adhesion molecules,which included CD44s,CD44v6,E cadherin,alph-catenin and beta-catenin in two human salivary ACC cell lines and Scid mice neoplasm models was investigated by immunohistochemistry. RESULTS: (1)Positive staining of adhesion molecules in lung metastatic foci of ACC was higher than that in subcutaneous implanted tumor mass.(2)The growing of ACC-M was slower in the cells of abdominal cavity implanted tumor,and also the differentiation of the former was better than the latter.(3)Weaker Positive staining of CD44v6 in ACC cells in vitro was showed,however,no positive staining was detected in lung metastatic foci cells of ACC M and the cells of subcutaneous tumor.CONCLUSION: The expression of CD44s in ACC cells was influenced by cell differentiation,and may affect the growth conditions;The expression levels of E cad/cat was positively correlative to the differentiation of ACC tumor cells;No significant correlation was revealed between the expression of CD44v6 and metastatic ability of ACC.

Journal Article↗
PubMed1999

[Research on expression of telomerase hTR gene in oral precancerous lesion and squamous cell carcinoma]

OBJECTIVE:The aim of present study was to investigate the expression of telomerase hTR gene in oral precancerous lesion and squamous cell carcinoma. METHODS:82 cases were detected by in situ hybridization technique for hTR gene,including 7 cases of normal oral mucosa,7 cases of hyperplasia lesions,30 cases of oral precancerous lesions(dysplasia lesion),38 cases of oral squamous cell carcinomas.RESULTS:Weaker signal of hTR gene expression was observed in normal oral mucosa and hyperplasia lesions,positive cell were present in basal layer,hTR positivity was 28.56%(4 of 14).The expression of hTR gene in the precancerous lesions was gradually strong associated with phenotypic progression and the degree of dysplasia;positive cell extended from basal layer to multi layered epithelium,hTR positivity was 60%(18 of 30).Strong hTR expression was observed in squamous cell carcinoma,the positivity was 81.58%(31 of 38).CONCLUSION:Telomerase is activated frequently during the late stage of oral precancerous lesion and may play a crucial role in oral squamous cell carcinogenesis.

Journal Article↗
PubMed1999

[Expression of p53 protein and PCNA in premalignant lesions of oral mucosa and its clinical significance]

OBJECTIVE:The study was to investigate the expression features of p53 protein and PCNA antigens in premalignant lesions of oral mucosa and further to discuss its clinical significance.METHODS: 50 samples were retrieved from the biopsy of the patients with suspicious premalignancy.Followed by the diagnosis pathologically,the sections were labeled with p53 and PCNA antigens by immunohistochemistry. RESULTS: In premalignant lesions,the progression staining with p53 and PCNA antigens were positively corresponding to the epithelial dysplasia from the basal layer to the keratinous layer. CONCLUSION: The p53 and PCNA antigens expressed synchronously in premalignant lesions of oral mucosa and exhibited direct correlation with the degree of epithelial dysplasia;The positive signals with p53 and PCNA antigens in the premalignant lesions may be the earlier incidence in carcinogenesis, which may initiated at the earlier stage of epithelial dysplasia.This phenomenon is deserving of clinicians' attention for discovering the premalignant lesions earlier;The detection of p53 and PCNA antigens would be helpful to find out the lesion which has the tendency turning to dysplasia.

Journal Article↗
PubMed1998

A novel photosensitizer, 2-butylamino-2-demethoxy-hypocrellin A (2-BA-2-DMHA). 1. Synthesis of 2-BA-2-DMHA and its phototoxicity to MGC803 cells.

The reaction of hypocrellin A (HA) with n-butylamine in pyridine under reflux leads to the formation of 2-butylamino-2-demethoxy-hypocrellin A (2-BA-2-DMHA), which is illustrated by ultraviolet-visible absorption spectra, proton nuclear magnetic resonance spectra, infrared spectra and mass spectra. The product exhibits stronger red-light absorption and has a much higher photopotentiation factor than HA (i.e., more than 200 versus four at a dose of 4 J cm-2 of red light on human gastric adenocarcinoma MGC803 cells). The mechanism of phototoxicity of 2-BA-2-DMHA on MGC803 cells irradiated with red light (lamada = 600-700 nm) has also been studied. An examination of extracted cellular DNA by agarose gel electrophoresis shows that the DNA has degraded into fragments with lengths which are multiples of approximately 180-190 base pairs (i.e., oligonucleosome size), a biochemical marker of apoptosis. Transmission electron microscopy reveals chromatin condensation around the periphery of the nucleus, which is also characteristic of apoptosis. This study suggests that 2-BA-2-DMHA is a potential photosensitizer and that its photoxicity to MGC803 cells proceeds via apoptosis.

Adenocarcinoma↗
PubMed1998

[The observation of the acute toxicity of the lanthanum and cerium to the buccal mucosa and systemic conditions of mice]

OBJECTIVE:The present study was to investigate the systemic and local acute toxicity of the lanthanum(La) and cerium(Ce) to the mice. METHODS: 0.2% and 1% La and Ce solutions were applied to buccal mucoa of mice.The systemic conditions and local histopathological changes were observed. RESULTS: The mice hadn't any systemic acute toxic reactions. Histological observation found that mucosal structures of most mice were almost normal,only a few mice showed the slight inflammation,but there were no significant differences between experimental and control groups. CONCLUSION: It was safe for local use of 0.2%,1% La and Ce to the buccal mucosa of mice. La and Ce may become a kind of safe caries-preventive drugs for local application.

Journal Article↗
PubMed1998

[The influences of lanthanum,cerium and fluoride on the activity of glucosyltransferase(GTF) and adherence of oral cariogenic bacteria in vitro]

OBJECTIVE:Study of the influences of lanthanum,cerium and fluoride on the activity of flucosyltransferase(GTF) and adherence of oral cariogenic bacteria. METHODS: The influences of lanthanum,certium and fluoride on the acitivity of GTF and adherences of Steptococcus sobrinus 6715,Lactobacillus 4356 and Actinomycetes viscosus 19246 in vitro were investigated. RESULTS: Lanthanum and cerium can efficiently inhibit the acitivity of GTF than fluoride. CONCLUSION: The result was given a data that lanthanum and cerium could be used as a cariostatic agent in future.At the same time the inhibition of the bacterial adherence by these trace elements was also revealed.

Journal Article↗
PubMed1998

[The influence of fluoride on the development of the osteoblast phenotype in rat calvarial osteoblasts: an in vitro study]

OBJECTIVE:The effects of low doses fluoride on the phenotypic development of rat fetal calvarial osteoblast were studied because the cellular mechanism of fluoride promotes the increasing of bone volume clinically is unclear. METHODS:The influence of fluoride on the rat first passage osteoblast were valuated by histochemistry, enzyme-histochemistry and electron microanalysis in vitro.RESULTS:The study had revealed that not only the bone tubular and the degree of mineralization, but also the activity expression of alkaline phosphatase of osteoblasts in fluoride group were better than the control group. CONCLUSION:The results suggested that low doses fluoride might not only increase the proliferation and differentiation of osteoblast precursors as well as the production and activity of alkaline phosphatase; but also favored the mineralized formation of osteoblast nodules.

Journal Article↗
PubMed1998

[The effect of fluoride on bone extracellular matrix proteins expression in rat calvarial osteoblast in culture]

OBJECTIVE:The expression of various non-collagenous proteins and collagen protein on the rat fetal calvarial osteoblast cultured in low doses fluoride condition in vitro had been studied.METHODS:Our study applied the immunohistochemistry technique to detect the expression of bone sialoprotein, osteocalcin, osteopontin, alkaline phosphatase and type I collagen expressed in the bone matrix.RESULTS:They demonstrated that there were difference in the location and function of the collagenous and non-collagenous proteins in the development of bone matrix.CONCLUSION:The present results revealed that fluoride might enhance the proliferation activity of osteoblast precursors; simultaneously, fluoride might accelerate the phenotypic development of osteoblast and the expression of collagenous and non-collagenous proteins. As a result,low doses fluoride played a favorable role in the development of bone extracellular matrix.

Journal Article↗
PubMed1998

[The effects of fluoride and dexamethasone on the phenotypic development of osteoblast grown on the demineralized dental root surface]

OBJECTIVE: To investigate the effects of the phenotypic development of osteoblast growing on the periodontitis affected root surface in the condition with fluoride and dexamethasone.METHODS:Cell culture technique in vitro had been used to study the growth condition of MC3T3-E1 osteoblast line on the surf ace of cementum treated with various methods.RESULTS:The present study showed that osteoblast treated with fluoride and dexamethasone had a better cellular growth behavior.CONCLUSION: The results demonstrated that demineralization procedure by citric acid might promote the osteoblasts attachment and growth on root surface; and dexamethasone and low dose fluoride were of benefit to maintain the phenotype of osteoblast as well as promote the maturation of bone-like matrix and increase the mineralization formation.

Journal Article↗
PubMed1997

Expression and mutation of the tumor suppressor gene p53 in AIDS-associated Kaposi's sarcoma.

Alteration of the p53 gene is the most frequent event reported in human cancer, and p53 mutations have been observed in various neoplasms, including certain forms of skin cancer. Therefore, we postulated that p53 may also be involved in Kaposi's sarcoma associated with AIDS (AIDS-KS). Expression of the p53 gene was examined in freshly isolated tumor biopsy specimens from 15 patients with AIDS-KS. p53 mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in both the AIDS-KS tumors and in normal skin control samples. p53 protein was detected in 4 of the 15 AIDS-KS specimens by immunohistochemical staining. Single-strand conformation polymorphism analysis PCR-products (PCR-SSCP) was used for detection of mutations of the p53 gene. One of the p53 positive AIDS-KS samples showed mobilized shifts in exon 6 suggestive of a mutation. Sequencing data showed the mutation to be located in codon 210. We examined other mechanisms that could stabilize p53 protein. SV40 large T antigen and adenovirus E1B protein were not found in the AIDS-KS specimens. MDM2, a p53-binding protein, was also detected in five of the AIDS-KS specimens, two of which also contained p53-positive cells. These observations suggest that the tumor suppressor gene p53 may be involved in the pathogenesis of AIDS-KS.

AIDS-Related Opportunistic Infections↗
PubMed1997

[Immunohistochemical detection of PCNA and p53 protein in the premalignant lesions and squamous cell carcinomas of the oral mucosa]

PCNA and p53 protein expression were detected by immunohistochemical technique in 39 oral premalignant and malignant lesion;which included 11 oral mucosal leukoplakia(LK),9 oral lichen planus (LP),7 in situ carcinomas(ISC) and 12 squamous cell carcinomas(SCC);in order to investigate the significance of PCNA and p53 Protein overexpression in predicting malignant transformation.The results showed that the gradual strong expression of PCNA and mutated p53 protein positive signal from premalignant to malignant lesions.The remarkable correlation were found on PCNA expression between LK and ISC; on p53 protein expression between SCC I grade and SCC II grade and on PCNA and p53 protein expression between premalignant and malignant lesions.The results imply that expression of PCNA and mutated p53 protein may be as indicators for potential malignant development in benign lesions of oral mucosa premalignant.

Journal Article↗
PubMed1997

[The influences of lanthanum,cerium and fluorine ions to the activity of collagenase degrading cemental collagens]

The influences of trace elements lanthanum,cerium and fluorine to the activity of clostridium histolyticum collagenase(CHC) during the period of CHC degrading the cemental root collagen in vitro is studied.The results reveal that La(3+) can significantly inhibit the activity of the CHC than Ce(3+) and F(-). Therefore it suggests that lanthanum may be used as a new kind of element in preventing root caries.The mechanisms of above functions are also discussed.

Journal Article↗
PubMed1996

Transcription of human herpesvirus-like agent (HHV-8) in Kaposi's sarcoma.

Recently, DNA sequences of what appear to be a unique human herpesvirus-like agent (HHV-8) have been detected in different types of Kaposi's sarcoma (KS) tumors (Chang, Y., E.C. Cesarman, M.S. Pessin, F. Lee, J.C. Culpepper, D.M. Knowles, and P.S. Moore. 1994. Science (Wash. DC). 266:1865-1869). To further elucidate the possibility that HHV-8 plays a role in the pathogenesis of KS, the expression of HHV-8 RNA was examined in fresh KS tissue specimens which were found to harbor HHV-8 DNA by polymerase chain reaction (PCR). The transcription of HHV-8 RNA was detected by RT-PCR in 26 of 29 specimens (89.7%) of the KS tumors including 2 of 3 CKS and 24 of 26 AIDS-KS. No positive signal was detected in eight biopsy specimens of normal skin from healthy donors. By Northern blot analysis, the expression of HHV-8 was detected in 2 of 10 KS tumors examined. Furthermore, the RNA transcripts were observed in endothelial cells lining the irregular vascular spaces and perivascular spindle-shaped cells histologically characteristic of KS in 2 out of 8 different KS specimens examined by in situ hybridization using an antisense probe specific of HHV-8. The detection of RNA expression of HHV-8 in KS tumors further supports the possible etiopathogenic role of this virus in the development of KS.

Base Sequence↗
PubMed1996

[Recurrent fetal cellular rhabdomyoma:histopathological and ultrastructural observations]

A mass of the neck in an 8-year-old boy diagnosed with recurrent fetal cellular rhabdomyoma was reported.The recurrent tumor consisted of undifferentiated round and short spindle cells and immature striated muscle cells,which was similar to the primary tumor occured in five years ago.However,there were more large round myoblasts which mainly located at the periphery of the tumor and osteoid stroma in the recurrent case immuno-histochemistry stain and ultrstructure observation suggested that these were undifferntiated mesenchymal cell and myoblasts.The differential diagnosis from fibrosarcoma,highly differentiated rhabdomyosarcoma,and hemangiopericytoma were dicussed.Author considered FRMs has a recurrent and malignant change tendency though it belongs to benign tumor.

Journal Article↗