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Biomedical subjects

W Fang

Publications and source records attributed to W Fang.

At least 55 records · Page 3Linked to original sources
PubMed1999

Molecular cytogenetic detection of trisomy 21 in interphase nuclei and metaphase chromosomes.

OBJECTIVE: To explore the potential application of molecular methodology in the detection of numerical chromosome aberration for clinical diagnosis and prenatal diagnosis of Down's syndrome. METHODS: The primed in situ labelling (PRINS) procedure was carried out by in situ annealing of specific oligonucleotide primers to chromosome 13, 16, 18, 21, X and Y, respectively, followed by primer elongation by a Taq polymerase in the presence of labelled nucleotides. Detection of the labelling sites was performed by immunocytochemistry and conventional fluorescence microscopy. RESULTS: Under the stringent annealing temperature, chromosomes 13, 16, 18, X and Y were specifically labelled at centromeres and the procedure was carried out successfully on interphase nuclei as well as on metaphase spreads with easily scorable signals. In 33 cases of uncultured peripheral blood lymphocytes and 11 cases of uncultured amniocytes tested, two fluorescence signals were shown on more than 87.6% interphase nuclei when chromosomes 13, 16, 18 were investigated. Sex chromosomes were correctly detected in the same way. Blind tests on peripheral blood lymphocytes from 14 cases of normal individuals and 12 cases of Down's syndrome patients and on 9 cases of amniocytes showed that when chromosome 21 was detected by PRINS, two fluorescence spots as positive signals were visible on 89.3% normal nuclei and three spots on 88.8% trisomic nuclei. The above results were fully compatible with karyotypic analysis. CONCLUSION: PRINS provides a rapid and efficient method for the clinical diagnosis or prenatal diagnosis of trisomy 21.

Amnion↗
PubMed1999

[Evaluation of pre- and post-operational esophageal manometric findings with achalasia].

OBJECTIVE: To evaluate the manometric feature of pre- and post-operation with achalasia and the result of surgical myotomy through abdominal incision. METHODS: The manometric studies were performed in 23 pre- and 11 post-operational patients, including 11 patients who received both pre- and post-operational studies. 24 hour pH monitoring was performed in 11 after surgical myotomy. RESULTS: Achalasia, a motor disorder of the esophageal body, and hypertension of the resting LES impaired relaxation. The incidence of reflux was 22.2%. CONCLUSIONS: Surgical myotomy through abdominal incision is an effective procedure. It is necessary to avoid LES incompetence or reflux esophagitis.

Adult↗
PubMed1999

[Gene expression of lipopolysaccharide receptor CD14 and tumor necrosis factor-alpha in rats after thermal injury].

OBJECTIVE: To investigate changes in lipopolysaccharide receptor CD14 and tumor necrosis factor-alpha (TNF-alpha) gene expression in vital organs, and their significance in the pathogenesis of systemic inflammation after burns. METHODS: Wistar rats were subjected to a 35 percent full-thickness scald injury, then sacrificed pre-burn, and postburn 12, 24, 48, 72 hours, respectively. Tissue samples from liver, kidney, lung and intestine were collected to measure CD14 and TNF-alpha mRNA expression. Peritoneal macrophages were harvested by peritoneal lavage to determine CD14 mRNA expression. RESULTS: CD14 mRNA expression increased markedly after thermal injury, peaking at both 12 and 48 hours. Likewise, CD14 mRNA levels were significantly up-regulated in peritoneal macrophages. Gene expression of TNF-alpha elevated markedly in liver, lungs, and kidneys after acute insults. Positive correlation was found between CD14 mRNA and TNF-alpha mRNA in liver, lung, and kidney tissues. CONCLUSIONS: Thermal injury per se can markedly up-regulate both CD14 and TNF-alpha gene expression in various organs. Excessive CD14 mRNA expression may enhance synthesis and release of TNF-alpha stimulated by endotoxin translocation, and the interaction between CD14 and TNF-alpha may play an important role in mediating multiple organ damage secondary to major burns.

Animals↗
PubMed1999

[Expression of membrane-type I matrix metalloproteinase and its correlation with gelatinase A activation in cancer cell lines].

OBJECTIVE: To study the expression of membrane-type I matrix metalloproteinase (MT1-MMP) and its correlation with gelatinase A (MMP2) activation. METHODS: Reverse transcription PCR, northern blots and western blots were employed to detect the expression levels of MT1-MMP mRNA and MMP2 protein in 4 human melanoma cell lines, 2 human lung cancer cell lines and 2 human prostate cancer cell lines. RESULTS: All the cancer cell lines expressed MT1-MMP mRNA, and the MT1-MMP mRNA level in the 4 melanoma cell lines was significantly higher than that in the lung and prostate cancer cell lines. Activated MMP2 proteins were only detected in the melanoma cell lines, whereas PG, a lung cancer cell line, which secreted pro-MMP2 and expressed low level of MT1-MMP, could not produce activated MMP2. CONCLUSIONS: The level of MT1-MMP expression was highly associated with MMP2 activation.

Blotting, Northern↗
PubMed1999

[Isolation and characterization of human prostate cancer cell subclones with different metastatic potential].

OBJECTIVE: To isolate and characterize cancer cell subclones with different metastatic potential from human metastatic prostate cancer cell line (PC-3M). METHODS: Using limited dilution, in vitro growth, Matrigel invasion assay, soft agar cloning and in vivo tumorigenicity and spontaneous metastasis assay in nude mice, were isolated and characterized four subclones with different metastatic potential. RESULTS: Four subclones derived from PC-3M were 1E8, 2E7, 2B6, 2B4. Each subclone exhibited a different metastatic potential when inoculated into nude mice. Among these subclones, 1E8 expressed as the highly metastatic phenotype, with 100% metastasis frequency 5 weeks after subcutaneous inoculation into nude mice, whereas 2B4 was not metastatic. In vitro 1E8 was found to be the most highly invasive cell line in Matrigel invasive assay (98 +/- 24) and had the most clones in soft agar cloning assay (265 +/- 39) while 2B4 was found to have the least invasive abilities (12 +/- 4) and the least clones (137 +/- 14). CONCLUSION: Successful establishment of these subclones with different metastatic potential may be valuable for further study on the molecular mechanisms of cancer metastasis and cloning of cancer metastasis-related genes.

Animals↗
PubMed1998

Protein expression by Streptococcus uberis in co-culture with bovine mammary epithelial cells.

Three strains of Streptococcus uberis isolated from dairy cows with mastitis were co-cultured with a bovine mammary epithelial cell line (MAC-T) in Dulbecco's modified Eagle's medium without fetal bovine serum. Protein profiles from culture supernatants and bacterial pellets among different treatments were compared by electrophoresis. There were proteins induced or having increased expression in both supernatant and surface-associated samples from S. uberis co-cultured with MAC-T cells. Some of these proteins were recognized by antibodies in serum obtained from a cow infected by S. uberis. In supernatant samples, there were two distinct protein bands at 35 and 36.8 kDa for all three strains of S. uberis co-cultured with MAC-T cells. These two bands were absent when bacterial protein synthesis was inhibited by chloramphenicol. This study clearly indicates that bacterial protein expression was regulated in response to co-culture with mammary epithelial cells.

Animals↗
PubMed1998

Self-reactive B lymphocytes overexpressing Bcl-xL escape negative selection and are tolerized by clonal anergy and receptor editing.

Self-reactive B cells Tg for both a bcl-xL death inhibitory gene and an Ig receptor recognizing hen egg lysozyme (HEL-Ig) efficiently escaped developmental arrest and deletion in mice expressing membrane-bound self-antigen (mHEL). In response to the same antigen, Tg HEL-Ig B cells not expressing bcl-xL were deleted, while cells expressing bcl-2 were arrested at the immature B stage. Bcl-xL Tg B cells escaping negative selection were anergic in both in vitro and in vivo assays and showed some evidence for receptor editing. These studies suggest that Bcl-x may have a distinct role in controlling survival at the immature stage of B cell development and demonstrate that tolerance is preserved when self-reactive B cells escape central deletion.

Animals↗
PubMed1998

Decreased growth of Streptococcus uberis in milk from mammary glands of cows challenged with the same mastitis pathogen.

Milk samples from mammary glands challenged with Streptococcus uberis and from unchallenged mammary glands were selected for analyses of bacterial growth, antibody response, and lactoperoxidase activity. All challenged mammary glands became infected with isolation of S. uberis and elevated somatic cell counts in milk during the first week after challenge. In vitro growth of the homologous challenge strain and a heterologous strain of S. uberis was significantly lower in milk from challenged mammary glands than in milk from control mammary glands at 3, 5, and 7 days after challenge. Removal of casein significantly reduced bacterial growth. In general, antibodies specific to S. uberis started to increase at day 3 post-challenge and were higher in milk from challenged mammary glands than in milk from control mammary glands. There was also a marked increase in total IgG in milk from challenged mammary glands. Growth of S. uberis increased following heat treatment at 56 degrees C of pooled milk or whey samples from challenged mammary glands. Growth of S. uberis correlated negatively with the specific antibody response to the bacteria (P < 0.001). Lactoperoxidase activity varied among cows and among different samples over time and did not appear to contribute to decreased growth of S. uberis. These results suggest that decreased growth of S. uberis in milk from challenged mammary glands in comparison to milk from control mammary glands could result from the interaction of antibodies with complement components.

Animals↗
PubMed1998

Effect of interleukin-6 on the growth of human lung cancer cell line.

OBJECTIVE: To investigate the effect of interleukin-6 (IL-6) on the growth of human lung cancer in vivo as well as in vitro. METHODS: To examine the mRNA level of IL-6 receptor (IL-6R) in high-metastatic human lung giant cell carcinoma cell line PG by means of reverse transcription polymerase chain reaction (RT-PCR). To assess the existence of IL-6 receptor complex (including IL-6R and gp130) with the treatment of PG cells by use of recombinant human IL-6 (rhIL-6), recombinant human oncostatin M (rhOSM), and recombinant human leukemia inhibitory factor (rhLIF), respectively. To detect the expression of IL-6 by Northern blotting hybridization and bioactive assay. To identify the effect of IL-6 secreted by PG cells by use of IL-6 and IL-6R antisense oligodeoxynucleotides (ODNs), and specific neutralizing antibody to IL-6. To document the influence of IL-6 on PG cells growth in vivo through the strategy of the transfection of expression vector inserted antisense IL-6 cDNA. RESULTS: RT-PCR analysis revealed that PG cells expressed IL-6R mRNA. Any one of the recombinant cytokine IL-6, OSM and LIF stimulated the growth of PG cells in vitro in a concentration-dependent manner. These results demonstrated IL-6 receptor complex exist in PG cells. At the same time, PG cells expressed IL-6 mRNA and secreted bioactive IL-6. Both IL-6 antisense ODNs and IL-6R ODNs inhibited PG cells proliferation. Treatment of PG cells with IL-6 antibodies reduced the growth of PG cells in vitro. PG cells transfected with IL-6 antisense expression vector showed a decreased growth in nude mice. CONCLUSION: IL-6 functions as an autocrine growth stimulator for PG cells in vivo as well as in vitro.

Animals↗
PubMed1998

[Correlation between p53 gene mutation and protein expression in 30 cases of human lung cancer].

OBJECTIVE: To investigate the correlation between p53 gene mutation and protein expression and discuss the sensitivities of immunohistochemistry and PCR-SSCP in detecting p53 abnormalities in lung cancer. METHODS: Immunohistochemistry, PCR-SSCP, and PCR-sequencing were used. RESULTS: 22 of 30 patients showed p53 mutations by PCR-sequencing. Mutations of 8 patients (36%) located on exon 5, 2(9%) on exon 6, 7 (32%) on exon 7, and 5(23%) on exon 8, respectively. 14 patients (64%) showed missense mutations, and 4(18%) neutral mutations, 3(14%) frameshifts and 1(5%) splice site mutation. In all mutations, G:C-->T:A transversions accounted for 41%(9/22). p53 missense mutations were found in all 10 patients whose immunohistochemistry and PCR-SSCP were both positive. Nine of 10 patients whose PCR-SSCP was positive but immunohistochemistry negative had p53 mutations, including 4 patients with neutral mutations, 3 frameshift mutations, 1 missense mutation, and 1 splice site mutation. In 10 patients whose immunohistochemistry was positive but PCR-SSCP negative, only 3 showed p53 missense mutations. CONCLUSION: Most of p53 mutation sites located on exon 5 and exon 7 in lung cancer of China. Missense mutations and G to T transversions were prevalent. If both PCR-SSCP and immunohistochemistry gave the positive results, p53 missense mutations may be expected.

Adenocarcinoma↗
PubMed1998

[Interleukin-12 gene transfection into murine B16 melanoma cells suppresses tumorigenicity and decreases metastatic potential].

OBJECTIVE: To study the tumorigenicity and metastasis of poorly immunogenic murine B16 melanoma cells transfected with murine interleukin-12 (IL-12) gene. METHODS: Two recombinant vectors containing the full length cDNA of p40 or p35 subunit of IL-12 were constructed. They were cotransfected into B16 melanoma cells by LipofectAMIN method. The expressions of p40 and p35 mRNAs were analyzed by means of reverse transcription polymerase chain reaction (RT-PCR). The secretion of bioactive IL-12 was detected by bioassay (measuring the proliferative response of PMA-activated murine splenocytes). To determine the effects of IL-12 secreted by genetically engineered B16 cells (B16T-IL12) on tumorigenesis and metastasis, the cells were inoculated s.c. or i.v. into C57BL/6 mice. RESULTS: B16T-IL12 cells expressed both p40 and p35 mRNAs, also produced bioactive IL-12. Only 70% of the mice injected with B16T-IL12 cells developed palpable tumors. The emergence of palpable tumors in the mice inoculated with B16T-IL12 cells was significantly delayed (P < 0.01), the growth rate of the tumors was obviously decreased (P < 0.01), and the survival time of tumor-bearing mice was prolonged substantially (P < 0.01), compared with the control B16 or B16Tneo cells. The incidence of experimental pulmonary metastasis of B16T-IL12 cells was inhibited, and the number of pulmonary metastases was reduced markedly, in contrast to the i.v. inoculation of B16 cells (P < 0.01). CONCLUSION: Transfection of IL-12 gene into B16 cells results in the inhibition of tumorigenesis and in the suppression of experimental pulmonary metastasis.

Animals↗
PubMed1998

[The suppressing effect of TIMP-3 gene transfection on the invasion and metastasis of human lung carcinoma cells line].

OBJECTIVE: The purpose of this study is to determine if increasing levels of tissue inhibitor of metalloproteinase 3 (TIMP-3) expression could suppress the malignant phenotype of human cancer cells. METHODS: The recombinant expression vector, which contains full length cDNA of human TIMP-3, was constructed and transfected into BE1 cell line by lipofectin technique. The invasive and spontaneous metastatic potential was examined. RESULTS: TIMP-3 mRNA expression in TIMP-3 gene transfected BE1 cells was upregulated as detected by Northern blot. The invasion of TIMP-3 gene-transfected cells across matrigel-coated filters was significantly decreased when compared with controls. Following subcutaneous injection into nude mice, the TIMP-3 transfected cells suppressed primary tumor growth, as characterized by reduced tumor incidence (9/12 vs 6/6), longer latency and reduced metastatic potential to the lungs (1/12 vs 5/6) and lymph nodes (5/12 vs 6/6). CONCLUSION: The results suggest that upregulation of TIMP-3 expression in BE1 cells resulted in suppression of the invasive potential of BE1 cells in vitro as well as tumorigenic and metastatic potential in nude mice.

Animals↗
PubMed1998

[p53 alterations in human lung cancer and their correlation with clinicopathological features and prognosis].

OBJECTIVE: To investigate p53 protein accumulations and p53 mutations in squamous cell carcinoma and adenocarcinoma of the lung and their correlation with clinicopathological features and prognosis. METHODS: Immunohistochemistry (LSAB) and non-isotopic PCR-SSCP were used to detect p53 abnormalities in lung cancer. RESULTS: The general positive rates for immunohistochemistry using anti-p53 monoclonal antibody Do-7 (DAKO) as first antibody was 50.5% in 95 cases of lung cancer, 56.5% (26/46) in squamous cell carcinoma and 44.9% (22/49) in adenocarcinoma. PCR-SSCP results showed that 39 cases (41.1%) showed abnormal bands. The mutation rate in squamous cell carcinoma was 47.8% (22/46) and 34.7% (17/49) in adenocarcinoma. In 15 (38.5%) cases, the mutations were located on exon 5, 3 (7.7%) were on exon 6, 13 (33.3%) on exon 7 and 8 (20.5%) on exon 8, respectively. The concordance rate of immunohistochemistry and PCR-SSCP was 77.9% (74/95). The mutation rates of p53 gene in N0, N1, N2 staged lung cancer were 22.6% (7/31), 44.2% (19/43) and 61.9% (13/21), respectively. The difference was statistically significant (P < 0.025). The 3 year survival rate in patients with p53 mutations was significantly lower than those without p53 mutations (P < 0.025). CONCLUSION: The location of p53 mutations in squamous cell carcinoma and adenocarcinoma of the lung were more commonly seen on exon 5 and exon 7. p53 mutations were associated with increased lymph nodes metastasis and reduced survival rate in squamous cell carcinoma and adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1998

[A study on the tumor suppressing effect of a specific point mutant p53 minigene in the expression regulated model with a tetracycline-transactivative response promoter].

OBJECTIVE: To establish a tetracycline-regulated expression model and to determine and verify whether a specific point mutant type p53 minigene, containing an Arg-->Leu substitution at amino acid 172, possesses a suppressing effect on human lung cancer. METHODS: The tumor suppressing effects of inducing apoptosis and inhibition of the formation of G418 resistant colonies of the specific point mutated p53 minigene in a structural expression vector on a human cancer cell line PG with preexisting dominant negative p53 were preliminarily verified. Then the specific p53 minigene was sub-cloned into a tetracycline-transactivative controlled expression vector pBPSTR1 by gene recombination methods. Through LipofectaMINE, the vector was transfected into PG cells under the presence of tetracycline (1.0 mg/ml), and the transfectants were screened in the selecting medium containing 1.5 micrograms/ml puromycin, the p53 minigene expression and tumor suppressing effects were studied dynamically in presence/absence (1.0/0 mg/ml) of tetracycline. RESULTS: The specific mutant p53 minigenes had a stronger tumor suppressing effect than wild type p53 minigene on colony formation and transient expression could induce PG cell apoptosis (P < 0.05). The tetracycline transactivative p53 minigene-regulated transgene model was successfully established. When tetracycline was absent, a large amount of apoptosis cells in transgenic passage colonies could be detected. Therefore the tumor suppressing effects were further verified. CONCLUSION: The specific point mutant p53 minigene may be a good candidate for cancer gene therapy. The tetracycline transactivative response promoter was found to be a good regulator of down stream gene expression, this may be useful in future gene therapy.

Animals↗
PubMed1998

[Zymographic analysis of MMPs in human carcinoma cell lines with different metastasis potential].

OBJECTIVE: To investigate the correlation between matrix metalloproteinases (MMPs) activities and metastatic potential of several groups of human carcinoma cells with different metastatic potential. METHODS: Several groups of human carcinoma cell lines (human lung carcinoma, human prostatic carcinoma and melanoma) with different metastatic potential were selected. By using cell culture, collection and concentration of conditioned media and zymographic analysis method the difference of MMPs production and activity among those cell lines were detected. RESULTS: The MMPs production capabilities of carcinoma cells rose following the increase of their invasive and metastatic potentials: that of PG is much higher than PAa's, and BE1 is higher also than CL3 and LH7. Advanced stage melanoma cell WM983a and WM451 product MMP-9, but primary stage cells don't. There are MMP-9 in the conditioned medium of prostatic carcinoma cell PC-3M, the metastatic clone of PC-3 which don't express MMP-9. CONCLUSION: The expression of MMPs especially MMP-9 of carcinoma cells is closely correlated to the metastatic and invasive potential.

Adenocarcinoma↗
PubMed1998

[Preoperative staging of esophageal carcinoma: comparison of endoesophageal ultrasonography, computerized tomography and conventional clinical staging].

OBJECTIVE: To evaluate the value of different methods in preoperative staging of esophageal carcinoma. METHOD: Thirty-six patients undergoing resection of esophageal carcinoma were examined with endoesophageal ultrasonography (EU) before operation. Eight of 36 patients could not be evaluated because of severe esophageal stenosis. Computerized tomography (CT) was performed in 21 patients. Comparison was made between stagings based on EU, CT as well as the conventional clinical staging system, respectively with surgical-pathological staging after resection. RESULT: The accuracy of conventional clinical staging for esophageal cancer was only 36%. The accuracy of CT in T, N and pTNM staging was 38.1%, 57.1% and 47.6% respectively. For EU, the figures were 77.8%, 72.2% and 72.2%, and were improved to be 85.7%, 78.6% and 83.1% when untraversable patients were excluded. CONCLUSION: While conventional clinical staging system lacks accuracy in evaluating esophageal carcinoma, CT makes only moderate improvement. Based on direct morphological examination of lesions, EU is highly accurate in preoperative staging of esophageal carcinoma, especially in evaluating the extent of luminal wall invasion and regional lymph node involvement. Therefore, EU is of critical value in the therapeutic selection for esophageal carcinoma.

Endosonography↗