PubMed Health⌕ Search

Biomedical subjects

Q Wang

Publications and source records attributed to Q Wang.

At least 217 records · Page 12Linked to original sources
PubMed2001

Inhibition of PYK2-induced actin cytoskeleton reorganization, PYK2 autophosphorylation and focal adhesion targeting by FAK.

Focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK2) are structurally related tyrosine kinases. They are implicated in regulating actin cytoskeleton organization, a process critical for cell migration, mitosis and tumor metastasis. In this paper, we demonstrate that, although both PYK2 and FAK were expressed and colocalized at focal adhesions in fibroblasts, microinjection of PYK2, but not FAK, in Swiss 3T3 fibroblastic cells led to reorganization of focal adhesions and cell rounding. PYK2-mediated actin cytoskeleton reorganization required the PYK2 N terminus, the focal adhesion targeting (FAT) domain, catalytic activity and autophosphorylation. Remarkably, FAK suppressed PYK2-mediated reorganization of focal adhesions and cell rounding. In addition, FAK inhibited PYK2 autophosphorylation and focal adhesion targeting, which might contribute to FAK-mediated suppression of PYK2's phenotypes. Further analyses demonstrated that the inhibition of PYK2 autophosphorylation required the FAK N terminus but not FAK tyrosine phosphorylation. The FAK FAT domain seemed to be critical for FAK-mediated suppression of PYK2 focal adhesion targeting. Taken together, these results demonstrate that FAK could inhibit PYK2 autophosphorylation, focal adhesion targeting and actin cytoskeleton reorganization, suggesting that the balance between FAK and PYK2 tyrosine kinases is important for regulating cellular morphology, cell migration and cell growth.

Actins↗
PubMed2001

Molecular cloning of three genes encoding G protein alpha subunits in the white root rot fungus, Rosellinia necatrix.

Three genes encoding G protein alpha subunits were cloned from the white root rot fungus, Rosellinia necatrix, and characterized. Only one copy of each gene was present in the genome. The protein sequences of Rga1, Rga2, and Rga3 are very similar to those of MagA, MagB and MagC of Magnaporthe grisea, respectively. Moreover, Rga1 is similar to Mod-D which is closely related to vegetative incompatibility in Podospora anserina, which suggests that Rga1 is important in the vegetative incompatibility reaction in R. necatrix. Reverse transcription PCR (RT-PCR) analysis of Rga1, Rga2, and Rga3 mRNA expression showed that the three genes were all transcribed in R. necatrix cells.

Amino Acid Sequence↗
PubMed2001

Isomeric effects on thiosulfate transformation and detoxification of 1,3-dichloropropene.

The fumigant 1,3-dichloropropene (1,3-D) is one of the most heavily used pesticides but also a suspected carcinogen. Previous research has shown that 1,3-D was rapidly transformed and detoxified by ammonium thiosulfate (ATS), a sulfur and nitrogen fertilizer. As common formulations contain cis and trans isomers at roughly equivalent ratios, this study was conducted to understand isomeric differences in thiosulfate transformation and detoxification of 1,3-D. Under the same conditions, reaction of cis-1,3-D with thiosulfate was more than three times faster than trans-1,3-D, which was correlated with a lower reaction activation energy for the cis isomer. The trans isomer was considerably more toxic to the luminescent bacteria Vibrio fisheri than the cis isomer, but the toxicity was reduced by 14 times after thiosulfate transformation. Mutagenic activity to strains of Salmonella typhimurium was observed for trans-1,3-D but was not detected after thiosulfate transformation. These results suggest that thiosulfate transformation detoxifies 1,3-D primarily by deactivating the trans isomer, and the reaction is toxicologically beneficial, as it negates the potential harmful effects of 1,3-D to the environment and human health.

Allyl Compounds↗
PubMed2001

Alterations in metastatic properties of hepatocellular carcinoma cell following H-ras oncogene transfection.

AIM: To demonstrate the relationship between H-ras oncogene and hepatocellular carcinoma (HCC) metastasis. METHODS: Activated H-ras oncogene was transfected into SMMC 7721, a cell line derived from human HCC, by calcium phosphate transfection method. Some metastasis-related parameters were detected in vitro, including adhesion assay, migration assay, expression of collagenase IV(c IV ase) and epidermal growth factor receptor (EGFR). RESULTS: The abilities of H-ras-transfected cell clones in adhesion to laminin (LN) or fibronectin (FN), migration, c IV ase secretion increased markedly, and the expression of EGFR elevated moderately. More importantly, these alterations were consistent positively with the expression of p21, the protein product of H-ras oncogene. CONCLUSION: H-ras oncogene could induce the metastatic phenotype of HCC cell in vitro to raise its metastatic potential.

Carcinoma, Hepatocellular↗
PubMed2001

The relationship between opsin overexpression and photoreceptor degeneration.

PURPOSE: To characterize the process by which overexpression of normal opsin leads to photoreceptor degeneration. METHODS: Three transgenic mouse lines were generated that express different levels of an opsin with three amino acid modifications at the C terminus. These modifications created an epitopic site that can be readily distinguished from the endogenous protein using a bovine opsin-specific antibody. Evidence of degeneration associated with opsin overexpression was provided by anatomic studies and electroretinogram (ERG) recordings. Western blot analysis was used to confirm the production of the transgenic opsin, and an enzyme-linked immunosorbent assay (ELISA) was used to determine the amounts of opsin overexpressed in each line. Immunocytochemistry was used to determine the cellular localization of transgenic opsin. Amounts of 11-cis retinal were determined by extraction and high-performance liquid chromatography (HPLC). RESULTS: Opsin expression levels in the three lines were found to be 123%, 169%, and 222% of the level measured in nontransgenic animals, providing direct correlation between the level of transgene expression and the severity of the degenerative phenotype. In the lower expressing lines, ERG a-wave amplitudes were reduced to less than approximately 30% and 15% of normal values, whereas responses of the highest expressing line were indistinguishable from noise. In the lowest expressor, a 26% elevation in 11-cis retinal was observed, whereas in the medium and the high expressors, 11-cis retinal levels were increased by only 30% to 33%, well below the 69% and 122% increases in opsin levels. CONCLUSIONS: The overexpression of normal opsin induces photoreceptor degeneration that is similar to that seen in many mouse models of retinitis pigmentosa. This degeneration can be induced by opsin levels that exceed by only approximately 23% that of the normal mouse retina. Opsin overexpression has potential implications in retinitis pigmentosa.

Amino Acid Sequence↗
PubMed2001

[Cloning of cNDAs involved in malignant transformation induced by glycidyl methacrylate].

The malignant transformation of human embryonic lung fibroblasts (HELF) induced by glycidyl methacrylate (GMA) in vitro was used as a model for comparing gene expression between the transformed cells and controls. Using mRNA differential display PCR(DD-PCR) technique, the three cDNA fragments up-regulated in the transformed cells were identified and highly homologous to human breast cancer transcription factor(ZABC1), Tbx3 and mouse ubiquitin conjugating enzyme(E2) gene. These results suggest that activation or inactivation of genes including ZABC1, Tbx3 and E2 may be involved in GMA-induced transformation.

Air Pollutants, Occupational↗
PubMed2001

[Expression of tumor suppressor genes p16, p21 and p53 in a pair of lung adenocarcinoma cell lines with different metastasis potentials: Anip973 and AGZY83-a].

OBJECTIVE: In order to investigate the suppression effect of tumor suppressor genes in lung adenocarcinoma. METHODS: p16 and p21 expression vectors were transfected into a pair of lung adenocarcinoma cell lines with different metastasis potentials: Anip973(high metastasis potential)and AGZY83-a (low metastasis potential). In the mean time, AGZY83-a, Anip973, AGZY83-ap16 and Anip973p16 were infected with recombinant adenovirus encoding wild- type p53 gene. The suppression effects of these genes were evaluated by cell growth curve, MTT, cloning efficiency assay, flow cytometric analysis and TUNEL technique. RESULTS: Overexpression of p16 gene in Anip973 and AGZY83-a could only lengthen the G(1) phase while increased expression of p21 in both of the cell lines was associated with significant lengthening of G(1) phase, decreased proliferation potential and decreased cloning efficiency. High efficient expression of wild-type p53 gene in AGZY83-a, Anip973, Anip973p16 and AGZY83-ap16 inhibited the growth of these four kinds of lung cancer cells and killed the cells in the end. Apoptosis was detected in all the four kinds of cells. The suppression effect of p53 gene was higher in Anip973 and Anip973p16 than in AGZY83-a and AGZY83-ap16 while co-expression of p53 and p16 in this pair of cell lines inhibited the cells more efficiently as compared with the expression of p53 gene. CONCLUSION: Increased expression of p21 gene suppressed the lung adenocarcinoma cells by G(1) arrest and the co-transfection of tumor suppressor genes p16 and p53 into the lung adenocarcinoma cell line proved more effective in lung cancer gene therapy.

Adenocarcinoma↗
PubMed2001

[Kinetics of in vitro drug release from chitosan and N-alkyl chitosan membranes].

By using the so-called "lag-time" method, we studied the effect of membrane thickness(h), initial drug concentration(Co) and flow rate(V) on the difusion coefficient(D) of model drug in membranes. The experiment indicates that D increases as h and v increase; D Keeps constant when C0 changes; Under the same condition, the D value of N-alkyl chitosan membrane is bigger than that of pure chitosan membrane.

Chitin↗
PubMed2001

[Evaluation of biocompatibility on titanium-zicornium alloy].

In this study, the general toxicity tests including cytotoxicity, haemolysis and oral mucous irratation of the Ti-Zr alloy were investigated. The results showed the level of cytotoxicity was grade 0, the haemolysis degree was 0.15% and no histomorphologic change was observed in the animals of Ti-Zr alloy groups. These data indicate that Ti-Zr alloy has good biocompatibility as a dental material.

Alloys↗
PubMed2001

[Cloning and sequence analysis of a pseudogene of liver regeneration augmenter in rats].

OBJECTIVE: To investigate the status of the augmenter of liver regeneration (ALR) in rat's genome. METHODS: Polymerase chain reaction (PCR) was used to amplify the genomic DNA of rat, with a set of specific primers designed according to the cDNA sequence of ALR. The products were ligated into pGEM Teasy vector. Two positive clones were sequenced separately. RESULTS: Two products were amplified from the rat's genome by PCR. After sequencing, one pseudogene was identified. The homology of the amino acid sequence between the ALR and its pseudogene was 88.8%. CONCLUSIONS: ALR pseudogene is found in rat's genome, implying that there is an ALR multigene family. This finding lays a foundation for further study of ALR molecular evolution mode.

Amino Acid Sequence↗
PubMed2001

[Role of angiotensin-(1-7) in amino-acid-neurotransmitter-mediated blood pressure regulation in rat rostral ventrolateral medulla].

The present study was undertaken to investigate the linkage between angiotensin-(1-7) [Ang-(1-7)] and the release of amino acid neurotransmitters in the the rostral ventrolateral medulla (RVLM) by techniques of microinjection, microdialysis combined with high performance liquid chromatography (HPLC)-fluorescent detection. Unilateral microinjection of Ang-(1-7) into the RVLM of anesthetized rats produced an increase in mean arterial pressure (MAP) accompanied by an increased release of glutamate (Glu). In contrast, microinjection of Ang779, a selective antagonist of Ang-(1-7) receptor, caused a decrease in MAP with a decreased release of Glu and an increased release of glycine, taurine and gamma-aminobutyric acid. The pressor effect of Ang-(1-7) and the depressor effect of Ang779 were in part blocked by corresponding antagonists of amino acid receptors. These results suggest that the pressor effect of Ang-(1-7) in the RVLM may be partially due to an increased release of Glu, whereas the depressor effect of Ang779 may be partially attributed to a decreased release of Glu and an increased release of inhibitory amino acid neurotransmitters.

Amino Acids↗
PubMed2001

[Cloning and sequence analysis of truncated S gene from circulation of patients with chronic hepatitis B virus infection].

OBJECTIVE: To find different mutated status of HBV DNA in circulation from chronic HBV patients. METHODS: Specially designed primers and polymerase chain reaction method were applied to amplify the whole S gene of HBV from the serum of 2 patients. After being sequenced, 4 clones were compared with HBV adr subtype (China strain) to identify the mutant sites. RESULTS: Sequencing results implied that there was a truncated large/middle S gene in the serum of the patients. Besides that, HBsAg and HBV DNA polymerase defective clones were also detected. CONCLUSIONS: Truncated middle S gene is found in the circulation of patients with chronical HBV infection, suggestive of a poor prognosis.

Cloning, Molecular↗
PubMed2001

[Atmospheric particulate mercury concentration in Changchun City and its dry deposition flux].

From July 1999 to January 2000, the particulate mercury(Hg(p)) concentration of five function sites and one contrast site were determined. In non-heating time, the particulate mercury concentration in urban atmosphere ranged from 0.022 to 0.398 ng.m-3 with an average of 0.145 ng.m-3 and the contrast site with an average of 0.084 ng.m-3. In heating time, the Hg(p) concentration in urban was in the range of 0.148-1.984 ng.m-3 with an average of 0.461 ng.m-3 and with an average of 0.211 ng.m-3 in the contrast site. The Hg(p) concentration in heating time was two times higher than that of non-heating time. Coal fire and wind-blown soil material were the two important sources of Hg(p). Wind-blown soil material contributed 7.9%-38.5% of the Hg(p) with an average of 24.1% in urban. Use theory model to estimate the dry deposition flux with the results of 43.06 micrograms.(m2.a)-1 in urban and 21.28 micrograms.(m2.a)-1 in the contrast site.

Air Pollutants↗
PubMed2001

Regulation of keratinocyte growth factor receptor and androgen receptor in epithelial cells of the human prostate.

PURPOSE: Stromal-epithelial interactions of growth factors and the androgen receptor may have implications for the pathophysiology of benign and neoplastic transformation of the human adult prostate. We investigated a possible interaction of keratinocyte growth factor with its receptor as well as with the androgen receptor signaling pathway in human prostatic epithelial cells. MATERIALS AND METHODS: Human prostatic epithelial cells were obtained from explant primary culture, established in DU145 cell conditioned medium and maintained in keratinocyte serum-free medium with supplements. Epithelial cells were characterized by light and electron microscopy, and immunocytochemical study using epithelial and mesenchymal markers. Androgen receptor, keratinocyte growth factor receptor and keratinocyte growth factor messenger RNA expression was measured by polymerase chain reaction (PCR). The response to 0.01 to 10 nM. dihydrotestosterone, 10 microM. flutamide and 1 to 1,000 ng./ml. keratinocyte growth factor was tested by [3H] thymidine assay. The difference in keratinocyte growth factor receptor and androgen receptor gene expression after treatment with and without keratinocyte growth factor and flutamide were determined by quantitative multiplex PCR and quantitated using densitometry analysis. RESULTS: Immunocytochemical and electron microscopy characterization revealed typical epithelial differentiation. PCR showed keratinocyte growth factor receptor and androgen receptor expression in epithelial cultured cells but no keratinocyte growth factor expression. Epithelial cells showed a significant time and dose dependent stimulation of cell proliferation with keratinocyte growth factor and dihydrotestosterone (p <0.05). When combined with the anti-androgen flutamide the effect of 100 ng./ml. keratinocyte growth factor was significantly decreased (p <0.05). At 100 ng./ml. keratinocyte growth factor quantitative multiplex PCR revealed stimulated keratinocyte growth factor receptor and androgen receptor messenger RNA expression. CONCLUSIONS: These results show that keratinocyte growth factor up-regulates the keratinocyte growth factor and androgen receptors in the absence of androgen. Thus, the androgen signaling pathway may be activated by growth factors such as keratinocyte growth factor in an androgen deficient environment.

Androgen Antagonists↗
PubMed2001

[Studies on inhibiting activities of five antitumour drugs to human cancer cell in vitro with MTT assay].

The inhibiting activities of five antitumour drugs including "An ke su" to human cancer cell lines coming from 19 patients were measured in vitro with MTT assay, which can provide proper antitumor agents for clinical chemotherapy. The evaluation rate of medicine sensitivity is 89.47%, which is same as the result of clinical therapy. This method indicates the response of tumour cells to "An Ke Su" and other agents. Being simple, sensitive and rapid, it proves to be valuable in clinical therapy.

Antineoplastic Agents↗
PubMed2001

[Causes and countermeasures about adverse reaction of traditional Chinese medicine].

The literatures about the adverse reaction (AR) of traditional Chinese medicine from 1915 to 1996 in China and some recent reports abroad were reviewed. The principal causes of the AR of traditional Chinese medicine were summarized and some corresponding preventive countermeasures were put forward. The principal causes of this problem were overdosage and drug abuse. The key problem to be solved is to adhere to "treatment according to syndrome differentiation" and the rational administration of traditional Chinese medicine.

Drugs, Chinese Herbal↗
PubMed2001

[The current situation and future of extracellular matrix materials for bone tissue engineering].

The requirements of ideal extracellular matrix materials for bone tissue engineering were stated, and the advantages and disadvantages of bioceramics, biodegradable synthetic polymers and natural polymers were analyzed. Based on these, we highlight a point that the ideal extracellular matrix materials for bone tissue engineering should be made up of bioceramics materials, synthetic polymers or natural polymers. These materials should possess a morphological structure of three-dimensional foam and have a self-mediated drug delivery system of bone growth factors. The design and manufacture of such compound extracellular matrix materials for bone tissue engineering is a very important and urgent challenge.

Biocompatible Materials↗