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Biomedical subjects

W Fang

Publications and source records attributed to W Fang.

At least 37 records · Page 2Linked to original sources
PubMed2000

Frequent frameshift mutations of RIZ in sporadic gastrointestinal and endometrial carcinomas with microsatellite instability.

Many lines of evidence suggest that the retinoblastoma protein interacting zinc finger gene RIZ is a strong candidate for the tumor suppressor locus on 1p36, a region commonly deleted in many human cancers with chromosomal instability. In addition, a role for RIZ in tumors of the microsatellite instability pathway is suggested by frequent frameshift mutations in hereditary non-polyposis colorectal carcinomas. Here we studied RIZ mutations in sporadic cancers with microsatellite instability. Frameshift mutations in the two coding polyadenosine tracks of RIZ were found in 19 (48%) of 40 gastric carcinomas, 6 (33%) of 18 endometrial carcinomas, 14 (26%) of 51 of colorectal carcinomas, and 7 (54%) of 13 cell lines. Eleven tumor tissues showed biallelic inactivation of RIZ. In contrast, no frameshift mutations were found in 70 microsatellite stable tumors. These results suggest an important role for RIZ in sporadic cancers with microsatellite instability.

Alleles↗
PubMed2000

Point mutation associated with X-linked dominant Charcot-Marie-Tooth disease impairs the P2 promoter activity of human connexin-32 gene.

Many lines of evidence suggest that connexin-32 gap junction is involved in the exchange of information and metabolites in the peripheral nervous system. It has been shown that connexin-32 protein and mRNA are expressed in Schwann cells that function as myelinating cells of the peripheral nervous system. The physiological importance of connexin-32 gap junctions in regulating the normal function of myelinating Schwann cell is indicated by recent findings that X-linked dominant Charcot-Marie-Tooth disease, a hereditary peripheral neuropathy, is associated with the mutations of connexin-32 gene. Recently, we encountered a Taiwanese family affected with X-linked dominant Charcot-Marie-Tooth neuropathy. Therefore, we investigated the possible mutation in the coding and noncoding regions of the connexin-32 gene of affected members of this family. Our results suggest that a G-to-A transition at the position -215 (in relation to the transcription initiation site) of the nerve-specific P2 promoter region is associated with the pathogenesis of X-linked dominant Charcot-Marie-Tooth disease. Further experiments using the promoter assay indicate that G-to-A mutation at the position -215 greatly impairs the transcriptional activity of connexin-32 P2 promoter. These findings propose that a reduced expression of connexin-32 mRNA and protein in the myelin sheath could be responsible for the development of X-linked dominant Charcot-Marie-Tooth neuropathy.

Animals↗
PubMed2000

Establishment and characterization of HKESC-1, a new cancer cell line from human esophageal squamous cell carcinoma.

The establishment of an esophageal cancer cell line can facilitate the search for molecular mechanisms involved in esophageal carcinogenesis. A new human cancer cell line, HKESC-1, was established from a primary moderately-differentiated squamous cell carcinoma of the esophagus from a 47-year-old Hong Kong Chinese man. The pathological characteristics (morphology, immunohistochemical, and electron microscopic studies), the tumorigenecity in nude mice, the cytogenetic features, the DNA ploidy, and telomerase activity of the cell line were investigated. The HKESC-1 cells have been maintained continuously in vitro for more than 16 months and passaged over 96 times. HKESC-1 cells grow as a monolayer, with a doubling time of 46 hours. The HKESC-1 cells are of a squamous epithelial origin, as shown by their immunopositivity with the anti-cytokeratin antibodies and ultrastructural demonstration of tonofilaments and desmosomes. The HKESC-1 cells possess characteristics of malignancy because they are highly tumorigenic in nude mice and have strong telomerase activity. The HKESC-1 cells had an aneuploid DNA content, as demonstrated by flow cytometric analysis. Cytogenetic analysis revealed hyperdiploidy of greater than 50 in 80% of analyzable metaphases. Chromosome gains and losses were common, and loss of the Y chromosome was a consistent numerical aberration. Additionally, many structural chromosomal abnormalities were encountered, with frequent breakpoints at 1p32, 7p22, 7q34, and 20q13. This newly established cell line serves as a useful model for studying the molecular pathogenesis, and testing new therapeutic reagents for esophageal squamous cell carcinoma.

Animals↗
PubMed2000

Effects of lactoferrin and milk on adherence of Streptococcus uberis to bovine mammary epithelial cells.

OBJECTIVE: To determine whether lactoferrin (LF) or milk influenced adherence of Streptococcus uberis to bovine mammary epithelial cells. SAMPLE POPULATION: Three strains of S uberis from cows with mastitis, pooled milk samples from 3 clinically healthy Jersey cows early in the lactation period, and bovine mammary epithelial cells from a clonal cell line. PROCEDURES: Adherence of S uberis to bovine mammary epithelial cells in the presence of various concentrations of LF or milk and after pretreatment of bacteria with LF or milk was tested. Bacteria were cultured with mammary epithelial cell monolayers for 1 hour. The culture supernatant was removed, and the epithelial cells were lysed. Adherence index was calculated as number of colony-forming units (CFU) in the cell lysate divided by number of CFU in the supernatant times 10,000. RESULTS: All 3 strains of S uberis were found to bind to purified LF and LF in milk. Addition of LF to the culture medium enhanced adherence of all 3 strains to mammary epithelial cells, whereas addition of milk enhanced adherence of 2 strains and decreased adherence of the third. Pretreatment of bacteria with LF or milk increased adherence of 1 of the strains but decreased adherence of the other 2. Increased adherence was antagonized by rabbit antibovine LF antibody. CONCLUSIONS: Results suggest that LF may function as a bridging molecule between S uberis and bovine mammary epithelial cells, facilitating adherence of the bacteria to the cells.

Alkanes↗
PubMed2000

Mapping of a minimal deleted region in human hepatocellular carcinoma to 1p36.13-p36.23 and mutational analysis of the RIZ (PRDM2) gene localized to the region.

Human chromosome band 1p36 commonly undergoes loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC) but the minimal deleted region remains to be mapped. This chromosomal region contains a candidate HCC suppressor gene, RIZ (PRDM2), that is a member of the PR (PRDI-BF1-RIZ homology)-domain-containing zinc finger gene family. One characteristic of this family is the unusual yin-yang involvement in human cancers. The PR-domain-containing RIZ1 product of the RIZ locus, in contrast to the PR-domain-minus product RIZ2, is commonly lost or underexpressed in HCC. Furthermore, RIZ1 can induce cell cycle arrest, apoptosis, or both and suppress HCC tumorigenicity in nude mice. To help identify the putative HCC locus on 1p36 and to evaluate a genetic role of RIZ in HCC, we studied 97 HCC cases and mapped a minimal deleted region in HCC to 1p36.13-p36. 23 between markers D1S434 and D1S436. Notably, RIZ mapped within this region and was found to undergo LOH in 37% (25/67) of HCC cases. Single-strand conformation polymorphism (SSCP) analysis, however, did not show mutations in the PR-domain region of RIZ1 in 49 cases of HCC examined. Our data suggest that the RIZ locus is a target of frequent deletion in HCC, but that the more common way of RIZ inactivation in HCC may not involve mutations that alter peptide sequences. Genes Chromosomes Cancer 28:269-275, 2000.

Alleles↗
PubMed2000

[Inhibition of growth and metastasis of human giant cell carcinoma of the lung by transfection of antisense VEGF121 cDNA].

OBJECTIVE: To explore the effects of blocking the VEGF/VEGF receptor paracrine pathway on growth and metastasis of human lung carcinoma cell line PG and to evaluate its potential application in gene therapy of cancer. METHODS: The eukaryotic expression vectors bearing either sense-VEGF121 cDNA or antisense-VEGF121 cDNA was constructed and transfected into PG cells. In vitro and in vivo tests such as Northern blotting hybridization, Western blotting immunochemistry analysis, as well as xenografting in nude mice were used to analyze the effect of antisense-VEGF. RESULTS: The transfectants stably expressing antisense VEGF121 were observed to produce markedly reduced 3.3 kb VEGF mRNA and 45 KD, 41 KD, 32KD VEGF proteins. When xenografted s.c. into nude mice, growth and metastasis of the antisense-VEGF transfected cell lines were greatly inhibited when compared with control cells. CONCLUSION: Antisense VEGF gene significantly inhibited tumor growth and metastasis and may provide an experimental example for the development of antiangiogenic gene therapy.

Animals↗
PubMed2000

[The significance of the expressions of lipopolysaccharide binding protein mRNA and lipopolysaccharide receptor CD14 mRNA in the liver of burned rat].

OBJECTIVE: To explore the significance and the correlation between enteric endotoxin translocation and hepatic endotoxin -- sensitivity -- enhancing system--lipopolysaccharide -- binding protein (LBP)/lipopolysaccharide receptor CD14 (LBP/CD14) after burn. METHODS: Wistar rats subjected to 35% III degree burn were employed as the model. The rats were randomly divided into three groups: i.e. normal control (C, n = 8) group, thermal injury (T, n = 10) group and recombinant bactericidal/permeability -- increasing protein (rBPI(21)) treatment (R, n = 6) group. The rats in T and R groups were sacrificed at 12 postburn hour (PBH) and the liver tissue was collected for the detection of the mRNA expressions of LBP, CD14 and tumor necrosis factor (TNFalpha) and blood samples collected for hepatic functional indices. RESULTS: The hepatic endotoxin content increased significantly postburn (P < 0.01), and the expressions of LBP/CD14 and TNFalpha mRNA in liver tissue increased obviously. However the use of rBPI(21) could evidently lower hepatic endotoxin content and inhibit the expression of tissue LBP/CD14 and TNFalpha. In addition, rBPI(21) could also significantly decrease serum level of glutamic -- pyruvic transaminase (ALT) (P < 0.01). CONCLUSION: Aggregation of endotoxin in liver due to postburn translocation might obviously stimulate the expression of LBP/CD14 mRNA locally. The up -- regulation of the expression of LBP/CD14 might be the principle molecular basis enhandced activity of translocated endotoxin on inflammatory cells.

Acute-Phase Proteins↗
PubMed2000

The value of 99mTc-MIBI myocardial perfusion spect imaging in detecting coronary artery disease in patients with valvular disease before operation.

OBJECTIVE: The aim of this study was to detect coronary artery disease using 99mTc-MIBI myocardial perfusion imaging in patients with valvular disease. METHODS: Thirty patients with valvular disease confirmed by echocardiography underwent 99mTc-MIBI myocardial perfusion imaging using multiSPECT 1h after stress test (exercise, dipyridamole or dobutamine test) and were performed coronary angiography within 1 month before valvular operation. RESULTS: For 29 out of the 30 patients, the results of 99mTc-MIBI myocardial perfusion imaging were similar with those of coronary angiography, the concordance rate was 96.7% and the negative predictability was 100%. CONCLUSION: 99Tc-MIBI myocardial perfusion imaging is a reliable non-invasive method for detecting coronary artery disease in patients with valvular disease and so as to draw up suitable operation programs for them.

Coronary Angiography↗
PubMed1999

Adherence and internalization of Streptococcus uberis to bovine mammary epithelial cells are mediated by host cell proteoglycans.

The role of cell glycosaminoglycans (GAG) on adherence and internalization of Streptococcus uberis to bovine mammary epithelial cells was evaluated by adherence/internalization competition assays, by removal of GAG from the host cell surface and by inhibition of GAG glycosylation in the host cell. Heparin (HEP), heparan sulfate (HSA), chondroitin sulfate A (CSA) and chondroitin sulfate B (CSB) inhibited adherence and internalization of S. uberis in a dose-dependent manner. However, inhibition was lower with CSA and CSB than that observed with HEP and HSA. Adherence and internalization were also inhibited upon treatment of mammary epithelial cells with GAG lyases. The greatest inhibition was observed with heparinase I. Tunicamycin, an inhibitor of mammalian cell glycosylation of cell surface glycoproteins, markedly inhibited internalization of S. uberis into mammary epithelial cells. Differences between strains were observed. These results suggest that a HSA proteoglycan receptor on the host cell surface may mediate S. uberis adherence to and internalization of bovine mammary epithelial cells.

Animals↗
PubMed1999

Relaxed negative selection in germinal centers and impaired affinity maturation in bcl-xL transgenic mice.

The role of apoptosis in affinity maturation was investigated by determining the affinity of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific antibody-forming cells (AFCs) and serum antibody in transgenic mice that overexpress a suppressor of apoptosis, Bcl-xL, in the B cell compartment. Although transgenic animals briefly expressed higher numbers of splenic AFCs after immunization, the bcl-xL transgene did not increase the number or size of germinal centers (GCs), alter the levels of serum antibody, or change the frequency of NP-specific, long-lived AFCs. Nonetheless, the bcl-xL transgene product, in addition to endogenous Bcl-xL, reduced apoptosis in GC B cells and resulted in the expansion of B lymphocytes bearing VDJ rearrangements that are usually rare in primary anti-NP responses. Long-lived AFCs bearing these noncanonical rearrangements were frequent in the bone marrow and secreted immunoglobulin G(1) antibodies with low affinity for NP. The abundance of noncanonical cells lowered the average affinity of long-lived AFCs and serum antibody, demonstrating that Bcl-xL and apoptosis influence clonal selection/maintenance for affinity maturation.

Animals↗
PubMed1999

Identification of lactoferrin-binding proteins in bovine mastitis-causing Streptococcus uberis.

All strains of Streptococcus uberis evaluated bound to lactoferrin (Lf) in milk as detected by polyacrylamide gel electrophoresis and Western blotting. A biotin-avidin-based microplate binding assay and ELISA also revealed that these bacterial strains bound to purified Lf. Binding of bacteria of Lf was not inhibited by mannose and galactose, indicating that glycosidic domains of the Lf molecule were not involved in binding. Lf binding was also unaffected by bovine transferrin. Western blot analysis demonstrated that there were at least two bacterial proteins involved in Lf-binding. Lf binding by S. uberis could enable this bacterium to acquire iron necessary for its growth.

Animals↗
PubMed1999

Evaluation of a postmilking teat disinfectant containing a phenolic combination for the prevention of mastitis in lactating dairy cows.

A trial was conducted for 12 months in a herd of 120 Holstein cows in order to determine the efficacy of a teat disinfectant, which contained a phenolic combination, for the prevention of bovine intramammary infections during lactation. Postmilking teat disinfection was compared to a negative control using a split-udder experimental design. The percentage of quarters newly infected by mastitis pathogens was 45% lower in mammary glands with teats that had been dipped in the experimental teat disinfectant after milking than it was in undipped controls. New infections caused by Streptococcus uberis, Staphylococcus aureus, coagulase-negative Staphylococcus species, and Corynebacterium bovis were significantly lower in mammary glands with teats that had been dipped in the experimental teat disinfectant than in undipped controls. No statistical differences in the incidence of clinical mastitis between treatment groups were observed. No irritation or chapping of teats dipped in the experimental teat disinfectant were observed. The results of this study suggest that the experimental teat disinfectant containing a phenolic combination is an effective postmilking teat disinfectant for use in the prevention of new intramammary infections by both contagious and environmental mastitis pathogens.

Animals↗
PubMed1999

[The time course and tissue distribution of endotoxin in rats after thermal injury].

OBJECTIVE: To observe the time course and tissue distribution of endotoxin, and to evaluate the potential role of local endotoxin in mediating multiple organ damage following burns. METHODS: Wistar rats were subjected to a 35 percent full-thickness scald injury. They were grouped according to time of sacrifice: no burn, and 12, 24, 48, 72 hours postburn. Tissue specimens from liver, kidneys, lungs and intestine were aseptically harvested to determine tissue endotoxin levels. In addition, blood samples were obtained for measurement of organ function parameters. RESULTS: It was found that endotoxin levels in liver, spleen and lungs increased markedly after thermal injury, with the highest level in liver. Meanwhile, serum GPT, GOT, CK-MB levels, and pulmonary myeloperoxidase(MPO) activities markedly elevated after scald injury, reaching a maximum between 12 and 24 hours. Intestinal diamine oxidase(DAO) activities tended to decrease at various time points postburn. In addition, there were highly positive correlations between pulmonary endotoxin levels and MPO activities, and also between renal endotoxin levels and serum Cr values. CONCLUSION: Burn injury per se can result in gut-derived endotoxin translocation which is mainly distributed to the liver, spleen and lungs. Endotoxin accumulated in local sites may play an important role in mediating multiple organ damage secondary to major burns.

Animals↗
PubMed1999

[Specific point-mutate p53 mini-gene transfectimg effects on biological behaviors of a human cancer cell line PG derived from human pulmonary giant carcinoma].

OBJECTIVES: To explore the suppressive effects of a murine genomic p53 minigene containing an Arg-->Leu substitution at its encoding amino acid 172 on biological behaviors of human carcinoma cell and evaluate its potential application in cancer gene therapy. METHODS: By LipofectaMINE and electraporation methods, this mutant p53 gene which lacked of exon 1 and intron 1 expression vector driven by CMV promoter was co-transfected with PCMVneo into PG cell in which dominant negative p53 pre-exists. A wild-type and another kind of genomic mutate-type p53 gene expression vector were transfected. The latter p53 gene encoding protein contained an Arg-->His substitution at the same position, and pBLuscript plasmid was used as control. All transfectants were screened by 500 micrograms/ml geneticin and identified by mouse specific p53 mRNA RT-PCR and Northern blot analysis. After transfection, the biological behavior changes were studied by colony formation and TUNEL test together with in-situ clone regression for chemosensitivity of anti-cancer drugs. RESULTS: The transfecting effects of this unusual p53 gene were surprisingly strong. They were more significant than those of the wild-type p53 and could suppress the formation of transgenic colonies and passage. The transgenic colonies were sensitive to be treated in adromycin and 5-Fu, and the gene transient expression could result in cell apoptosis. CONCLUSION: Codon 172 mutant (Arg-->Leu) p53 genomic DNA exhibited a strong suppressive transfecting effects on carcinoma cell, so it is a possible candidate to be used in cancer gene therapy.

Apoptosis↗
PubMed1999

[The effect of bactericidal/permeability-increasing protein on lipopolysaccharide-binding protein and lipopolysaccharide receptor CD14 mRNA expression in rats after thermal injury].

OBJECTIVE: To elucidate the possible mechanisms underlying beneficial effect of recombinant bactericidal/permeability-increasing protein (rBPI) on multiple organ damage secondary to major burns. METHODS: Wistar rats were subjected to a 35% full-thickness scald injury, and randomly divided into 3 groups: normal controls (n = 8), thermal injury (n = 21), and rBPI21 treatment (n = 12). In thermal injury and rBPI21 treatment groups, animals were sacrificed at 12 and 24 hours after burn, respectively. Tissue samples from liver, kidneys, lungs and intestine were collected to measure lipopolysaccharide-binding protein (LBP)/lipopolysaccharide receptor CD14 and tumor necrosis factor-alpha (TNF-alpha) mRNA expression. In addition, blood samples were obtained for measurement of organ function parameters. RESULTS: Treatment with rBPI21 could significantly decrease tissue LBP and CD14 mRNA expression in various organs (P < 0.05-0.01). Also, TNF-alpha mRNA expression in liver, kidneys and lungs were markedly inhibited by rBPI21 secondary to acute insults (P < 0.05-0.01). Moreover, in the rBPI21 treatment group, significant reduction in serum GPT levels and elevation in intestinal DAO activities were found compared to those in the thermal injury group (P < 0.05-0.01). CONCLUSIONS: Treatment with rBPI21 is effective in attenuating multiple organ damage resulted from gut origin endotoxin translocation after thermal injury, which might be associated with down-regulation effect of tissue LBP and CD14 gene expression by use of rBPI21.

Acute-Phase Proteins↗
PubMed1999

Toxicology of intrahepatic arterial administration of interventional phosphorus-32 glass microspheres to domestic pigs.

OBJECTIVE: To evaluate the toxic response to intrahepatic arterial administration of radioactive phosphorus-32 glass microspheres (32P-GMS) in domestic pigs. METHODS: Through selective catheterization of hepatic artery, 32P-GMS was infused to 5 healthy domestic pigs in a dosage equivalent to the therapeutic dose for human being, and 31P-GMS was infused to other 5 healthy domestic pigs. Two pigs served as the whole course blank controls. One pig from each group was surrendered to euthanasia at week 1, 2, 4, 8 and 16, respectively, and liver biopsies were performed on the rest of pigs at the corresponding time points. Liver tissues from different sites were taken for light and electron microscopy. The ultrastructural histopathological changes were evaluated semiquantitatively. RESULTS: The accumulative amount of 32P-GMS in the target tissue attained more than 90% of the total dose administrated. Histologically, abnormal hepatocytes were easily found at week 1 or 2. At week 4 they were less than at week 1 or 2, and endothelium of the sinuses were damaged prominently. At week 8 they were scarcely seen, and liver tissue recovered gradually. The histological features of liver tissue restored to normal at week 16. Semiquantitative analysis of ultrastructural morphology in the experimental group showed no statistical difference (P > 0.50) between the nuclear abnormality (Nabn) and mitochrondrial variability (Mvar) at week 1 or 2, but revealed prominent difference (P < 0.01, P < 0.001) as compared with those in other groups. In the experimental group the Nabn in tissues showed no significant difference (P > 0.20) between week 8 and week 16. CONCLUSION: 32P-GMS internal irradiation at the dosage equivalent to human therapeutic dosage exerts reversible injury to domestic pig liver tissue, and it takes more than 8 weeks for the injured liver tissue to recover.

Animals↗
PubMed1999

[Expression of tumor metastasis suppressor gene KAI1/CD82 in human cancer cell lines with different metastasis potential].

OBJECTIVE: To investigate the correlation of a newly-defined tumor metastasis suppressor gene KAI1/CD82 and metastatic potential of human cancer cell lines. METHODS: Expressions of KAI1/CD82 in eight human cancer cell lines of prostate, lung and melanoma with different metastasis potential were studied by Northern blot hybridization and the mutation were detected by PCR-SSCP. RESULTS: Expressions of KAI1 mRNA decreased in human prostate cancer cell lines PC3 and PC3M, and lung cancer cell line PG which were metastatic cancer cell lines (integral light density values: 0.0319, 0.0266 and 0.0549, respectively). Expression of KAI1 mRNA showed high level in PAa, a human lung cancer cell line with no metastasis (integral light density value: 0.7313). In human melanoma cell lines with different metastasis potential (WM35, WM1341b, WM983a and WM451), expression of KAI1 showed moderate expression (integral light density values are 0.1798, 0.1582, 0.1501, 0.1800 respectively). PCR-SSCP analysis indicated the existence of band shift in exon 7 of KAI1 gene in PC3, PG and PC3M. CONCLUSION: Decreased KAI1/CD82 expression may be associated with enhanced metastatic potential in prostate cancer cell lines and lung cancer cell line other than melanoma cell lines. The decreased expression may be partially nelaled with mutation of KAI1 gene.

Adenocarcinoma↗