Search PubMed⌕ Search

Biomedical subjects

W Zhou

Publications and source records attributed to W Zhou.

At least 127 records · Page 7Linked to original sources
PubMed2000

beta(1)-integrin and PI 3-kinase regulate RhoA-dependent activation of skeletal alpha-actin promoter in myoblasts.

RhoA GTPase, a regulator of actin cytoskeleton, is also involved in regulating c-fos gene expression through its effect on serum response factor (SRF) transcriptional activity. We have also shown that RhoA plays a critical role in myogenesis and regulates expression of SRF-dependent muscle genes, including skeletal alpha-actin. In the present study, we examined whether the RhoA signaling pathway cross talks with other myogenic signaling pathways to modulate skeletal alpha-actin promoter activity in myoblasts. We found that extracellular matrix proteins and the beta(1)-integrin stimulated RhoA-dependent activation of the alpha-actin promoter. The muscle-specific isoform beta(1D) selectively activated the alpha-actin promoter in concert with RhoA but inhibited the c-fos promoter. In addition, focal adhesion kinase (FAK) and phosphatidylinositol (PI) 3-kinase were required for full activation of the alpha-actin promoter by RhoA. Expression of a dominant negative mutant of FAK, application of wortmannin to cultured myoblasts, or expression of a dominant negative mutant of PI 3-kinase inhibited alpha-actin promoter activity induced by RhoA. These results suggest that RhoA, beta(1)-integrin, FAK, and PI 3-kinase serve together as an important signaling network in regulating muscle gene expression.

Actins↗
PubMed2000

Predominant role for C5b-9 in renal ischemia/reperfusion injury.

Previous work has indicated that complement is a mediator of ischemia/reperfusion (I/R) injury. To investigate the components of complement responsible for this effect, we examined a model of renal I/R injury in C3-, C4-, C5-, and C6-deficient mice. We occluded the renal arteries and veins (40-58 minutes) and, after reperfusion (0-72 hours), assessed renal structural and functional injury. C3-, C5-, and C6-deficient mice were protected from renal I/R injury, whereas C4-deficient mice were not protected. C6-deficient mice treated with antibody to block C5a generation showed no additional protection from I/R injury. Reconstitution with C6 alone restored the I/R injury in C6-deficient mice. Tubular epithelial cells were the main structures damaged by complement-mediated attack, and, in contrast, the renal vessels were spared. Neutrophil infiltration and myeloperoxidase activity were reduced in C-deficient mouse kidney, but by a similar extent in C3-deficient and C6-deficient mice. We conclude that the membrane attack complex of complement (in which C5 and C6 participate) may account for the effect of complement on mouse renal I/R injury. Neither C5a-mediated neutrophil infiltration nor the classic pathway, in which C4 participates, appears to contribute to I/R injury in this model. By contrast with other organs, such as the heart, the primary effect of complement in the ischemic area is on the parenchymal cell rather than the vascular endothelial cell. The membrane attack complex of complement is a potential target for prevention of I/R injury in this model.

Animals↗
PubMed2000

Syntaxin 1A is expressed in airway epithelial cells, where it modulates CFTR Cl(-) currents.

The CFTR Cl(-) channel controls salt and water transport across epithelial tissues. Previously, we showed that CFTR-mediated Cl(-) currents in the Xenopus oocyte expression system are inhibited by syntaxin 1A, a component of the membrane trafficking machinery. This negative modulation of CFTR function can be reversed by soluble syntaxin 1A peptides and by the syntaxin 1A binding protein, Munc-18. In the present study, we determined whether syntaxin 1A is expressed in native epithelial tissues that normally express CFTR and whether it modulates CFTR currents in these tissues. Using immunoblotting and immunofluorescence, we observed syntaxin 1A in native gut and airway epithelial tissues and showed that epithelial cells from these tissues express syntaxin 1A at >10-fold molar excess over CFTR. Syntaxin 1A is seen near the apical cell surfaces of human bronchial airway epithelium. Reagents that disrupt the CFTR-syntaxin 1A interaction, including soluble syntaxin 1A cytosolic domain and recombinant Munc-18, augmented cAMP-dependent CFTR Cl(-) currents by more than 2- to 4-fold in mouse tracheal epithelial cells and cells derived from human nasal polyps, but these reagents did not affect CaMK II-activated Cl(-) currents in these cells.

Animals↗
PubMed2000

Association analysis of variants in the core promoter region of angiotensinogen gene with essential hypertension in Tibetan population.

OBJECTIVE: To detect the variants in the core promoter region of angiotensinogen(AGT) gene, and to analyse the relationship between the AGT gene polymorphisms and essential hypertension in Tibetan population. METHODS: This is a case-control study consisting of 103 essential hypertensive subjects and 82 normotensive controls matched by age and sex. The variants in the AGT gene core promoter region were screened by polymerase chain reaction/single strand conformation polymorphism(PCR/SSCP) and further identified by automated sequencing. The A(-6)G polymorphism was determined in DNA extracted from leucocytes by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). RESULTS: (1) There were two different electrophoresis band patterns in PCR/SSCP analysis. PCR product direct sequencing showed that the two band patterns represented the AA, AC genotypes in the (-20) site of AGT gene respectively. The distribution of A(-20)C genotype was almost identical in essential hypertensive and normotensive groups (P>0.8). The A allele frequency was very high in both groups (control: 0.9175, hypertensive: 0.9124). (2)Distribution of genotype in the (-6) site of AGT gene was much different between the patient group and control group (P<0.005). The frequency of G allele was statistically higher in the patient group than in controls (0.374 vs 0.220, P<0.025). CONCLUSION: Both Tibetan hypertensives and normotensives have higher frequency of A allele in AGT gene (-20) site. The higher frequency of G allele in the AGT gene (-6) site in Tibetan hypertension patients suggests that this allele may be the genetic susceptibility factor in the proceeding of essential hypertension in the Tibetan population.

Angiotensinogen↗
PubMed2000

Mutagenicity of methyl tertiary butyl ether.

Methyl tertiary butyl ether (MTBE), the main component of oxygenated gasoline, is added to gasoline as an octane enhancer to reduce automotive emissions. We evaluated the mutagenicity of domestic MTBE using the Ames test, unscheduled DNA synthesis (UDS) assay, and NIH/3T3 cell micronucleus test. MTBE did not show any mutagenic potential in the Ames assay (TA98, TA100 strains) with or without rat liver-derived metabolic activation system (S-9). In rat primary hepatocyte UDS assay, a dose-response relationship was observed, which meant that MTBE might damage normal DNA and induce unscheduled DNA synthesis. MTBE did not show positive results in the NIH/3T3 cell micronucleus test. It could be concluded that MTBE has some degree of mutagenicity.

3T3 Cells↗
PubMed2000

Effect of leaded and unleaded gasoline on the mutagenicity of vehicle exhaust particulate matter.

With the removal of lead from gasoline and the use of new technologies, there have been some changes in vehicle emissions. In order to find out if the unleaded gasoline has the ability to reduce the emission of pollutants, leaded and unleaded gasoline were tested on a Santana engine dynamometer under a standard test cycle. The concentrations of hydrocarbons (HC) and carbon monoxide (CO) in emission were analyzed. The extracts of total exhaust particles were also collected and the components were detected by gas chromatography/mass spectrometry (GC/MS). A series of different end point genotoxicity tests, including the Ames test, the single cell gel electrophoresis (SCGE) assay, and micronucleus induction assay, were performed to investigate the mutagenicity in the two kinds of gasoline. We found that unleaded gasoline could reduce the emission of CO and HC and significantly decrease the quantity of vehicle exhaust particulate matter by 60%. As for the component analysis, only 23 kinds of organic substances adsorbed onto the particles were identified in the unleaded gasoline, while 32 kinds of compounds were detected in the leaded gasoline. The genotoxicity tests indicated that both types of gasoline could enhance the number of histidine-independent colonies in the Ames test, cause DNA damage, and increase the frequency of induced micronucleus in the Chinese hamster lung (CHL) cells. For the same particle weight, no difference was found between their mutagenicity. Because of the decrease in the emission of CO, HC, and particles in unleaded gasoline, this gasoline has some benefits for the environment and human health.

Animals↗
PubMed2000

[Effects of hepatitis B virus X gene on apoptosis and the activity of telomerase in HepG(2) cells].

OBJECTIVE: To observe the effects of hepatitis B virus X gene on hepatic carcinoma. METHODS: The expression vectors of HBs gene and HBc gene (pCEP4-S and pCEP4-C) were transfected into HepG(2) cells by electroporation technique, and the cells, HepG(2) cells which contained the expression vectors of HBs (pCEP4-X) were recovered and cultured stably. The activity index of telomerase and the apoptosis rates in three cell lines were determined by PCR-ELISA and flow cytometry. RESULTS: The 39.50% of cells expressed HBx gene came into S-phase of cell cycle, and the activity index of telomerase was higher in the cell line (3.95 +/- 0.07) than in other cell lines and control (F=20.85, P<0.01; d'=2.15, P<0.05) after synchronized culture. Induced by antisense oligonucleotides against telomerase the apoptosis of cell line expressed HBx gene reduced (apoptosis rate: 1.75%). The activity of cells also reduced with the dose increase of the antisense oligonucleotides and it showed a dose-response relationship. CONCLUSION: The activity of HepG(2) cell can be increased and the cell apoptosis can be reduced by HBx gene. It may be another malignant process of hepatocytes.

Apoptosis↗
PubMed2000

Fas ligand expression and apoptosis in primary rat hepatocytes induced by lipopolysaccharide.

OBJECTIVE: To study hepatocyte apoptosis induced by lipopolysaccharide (LPS) directly and indirectly, and to elucidate the mechanisms of liver damage in endotoxemia. METHODS: Rat hepatocytes were isolated using collagenase perfusion, and cultured in RPMI 1640 medium. After 24h or 48 h of LPS treatment at various concentrations (1, 5, 10 mug/ml), membrane-bound Fas ligand (mFasL) expression in hepatocytes was determined by immunocytochemistry, and apoptosis was detected by TUNEL. In another set of experiments it was examined whether LPS-treated hepatocytes and its supernatants can stimulate apoptosis in LPS-untreated hepatocytes. RESULTS: LPS markedly stimulated mFasL expression and apoptosis in hepatocytes in a dose and time (24-48 h) dependent manner. In the co-culture system LPS-treated hepatocytes significantly induced LPS-untreated hepatocyte apoptosis. In contrast, there was no apoptotic cells observed in the supernatant stimulation system. CONCLUSION: LPS not only directly causes hepatocyte apoptosis, but also indirectly induces apoptosis of LPS-untreated hepatocytes by way of stimulating mFasL expression in hepatocytes.

Animals↗
PubMed2000

[Analyses on the association of CA-repeat polymorphism and A1166-->C variant in the 3'-flanking region of AT(1)R gene with essential hypertension in Tibetans].

OBJECTIVE: To investigate whether CA-repeat polymorphism and A1166 --> C variant in the 3n-flanking region of AT(1)R gene are in association with the genetic susceptibily to essential hypertension (EH) in Tibetans. METHODS: A case-control study was carried out. Sibpair analysis and family linkage analysis were conducted. The CA-repeat polymorphism of AT &(1) R gene was identified by polymerase chain reaction(PCR) with fluorescence labeled dCTP as substrate and by semi-automatic sequence technology. The A1166 -->C variant was detected by PCR-RFLP. RESULTS: Association of AT&(1)R gene locus with EH was confirmed through the case-control study in well-characterized group of 113 Tibetan EH patients and 131 normotensives(chi(2)=26.44, P<0.001). A closer examination of this gene locus found 11 alleles from Tibetan population; allele A7 (138 bp) was more frequent in both the patients and the controls. Allele A8(140 bp) was in strong positive association with genetic susceptibility to EH in Tibetans. Frequency of allele A8 was 20.5% in EH and 7.3% in normotensives. The difference of allele frequencies between the groups was significant (chi(2)=9.64, P=0.002, OR=3.46, 95% CI 1.44-8.51). Affected sibpair analysis showed chi(2)=3.85, P=0.025; family linkage analysis gave Lod score of 0.80. No association between A1166 --> C variant in AT(1)R gene and EH in Tibetans was observed (P>0.05). CONCLUSION: The result suggests that CA-repeat polymorphism of AT(1)R gene be in association with EH in Tibetans, which implicates that AT(1)R gene may be in linkage disequilibrium with the causative genes of EH.

Adult↗
PubMed2000

[The sequence of the human PrP gene Exon I and its upstream segment has promoter-like activity].

OBJECTIVE: The human PrP gene locates at the short-arm of the 20th chromosome. This article is was to map the promoter that transcribes the human PrP gene. METHODS: The sequence of the human PrP gene Exon I and its upstream segment were amplified using PCR, and inserted into a CAT reporter plasmid pBL-CAT6 after sequence analysis. The values of the relative CAT expression under the control of this fragment were evaluated after transiently transfected into HeLa, COS7 and Sh-sy5y cell lines. The amounts of transcription activator SP1 in these three cell lines were calculated with band-shift assays. RESULTS: Analysis of the human PrP gene Exon I and its upstream segment showed a GC rich sequence, with several potential SP1 binding sites, but without any TATA-box. Under the control of this fragment, the CAT expressions were 2-3 folds increased in transient transfection. Quantity band-shift assays revealed that SP1 was enriched in HeLa cells, but undetectable in COS7 and Sh-sy5y cells. CONCLUSIONS: The sequence of the human PrP gene Exon I and its upstream segment functions as a promoter-like sequence, probably being as a weak TATA-less promoter. Cells derived from different tissues contain different amount of SP1. The activity of this promoter-like sequence seems to be independent of SP1 presence.

Cell Line↗
PubMed2000

[The immortalized cell lines induced by human papillomavirus type 16 (HPVS 16) YY1 binding-site mutants have some characteristics of transformed cells].

OBJECTIVE: To study the biological characteristics of the immortalized cell lines of human keratinocytes from foreskin induced by human papillomavirus type 16 (HPV 16) YY1 binding-site mutants. METHODS: The cellular extracts of immortalized cell lines were prepared and the cellular endogenous p53 proteins were determined with Western blot. The cellular telomerase activities were analyzed with TRAP. The immortalized cells were incubated in a soft agarose medium containing 10% FCS and the anchorage-independent growth abilities of the tested cell lines were evaluated. RESULTS: Western blot showed that the endogenous p53 protein in all 4 tested clones were undetectable. The telomerases were clearly identified within the 4 tested cell lines, and showed an increasing activity along with the passages of the cells. All the clones were unable to grow in the soft-agarose medium during the earlier passages, but three of them showed anchorage-independent-growth at the passages of 30-35. CONCLUSIONS: The immortalized cell lines induced by the HPV 16 YY1 binding-site mutants have active telomerase activity and ability of anchorage-independent growth.

Agar↗
PubMed2000

[Presence of genetic rearrangements in E1/E2 regions of episomal HPV 16 isolates from cervical carcinomas 5-8].

OBJECTIVE: Analysis of genetic situations of E1/E2 region of episomal HPV 16 isolates from cervical carcinomas. METHODS: Physical statues of HPV 16 DNAs from cervical carcinomas were analyzed by Southern blot hybridization. E1/E2 regions of episomal RPV 16 isolates were amplified by PCR, and the PCR products were cloned and sequenced. RESULTS: Eight isolates from totally 28 cases showed extrachromosomal HPV 16 DNA. PCR cloned sequence analysis revealed that all the eight isolates contained intact E1/E2 regions, whereas 4 isolates had different ratios of genetic rearrangements, including insertion of E1 repeat sequence and several deletions. Only one case showed the same G deletion at position 1138 as HPV 16 prototype. CONCLUSIONS: DNA rearrangements were present in E1/E2 regions of episomal HPV 16 isolates from cervical cancers and might play a role in tumorigenesis. Different viral genotypes in an identical tumor tissue might indicate that the tumor occurring at the same position of a patient may derive from two or even more cell clones.

DNA, Viral↗
PubMed2000

[Preparation of polyclonal antibody to human prion protein using the expressed GST-PrP fusion protein as antigen].

OBJECTIVE: Preparing specific antibody to prion protein. METHODS: Using prokaryotic expressed GST-PrP fusion protein as antigen, rabbits were immunized subcutaneously. RESULTS: ELISA assay revealed that the titer of the prepared antiserum against expressed PrP protein was as high as 1:128 000. Western blot test showed that the antiserum was able to react with the in vitro expressed intact and different lengths of C-terminus truncated PrP proteins, as well as the native PrP proteins from brain homogenization of human and mouse. CONCLUSIONS: The prokaryotic expressed GST-PrP fusion protein can efficiently elicit in immunized animals the PrP-specific antibody.

Animals↗
PubMed2000

Molecular cloning and protein expression of EC1-2 and EC3-4 epitopes of pemphigus vulgaris antigen.

OBJECTIVE: To clone and express EC1-2 and EC3-4 epitopes of PVA (pemphigus vulgaris antigen, desmoglein-3) in order to diagnose pemphigus and study the relationship between epitopes of PVA and anti-PVA antibody. METHODS: RNA was extracted from keratinocytes and the cDNA of epitopes EC1-2 and EC3-4 was synthesized by reverse transcription. Amplified genes of EC1-2 and EC3-4 were inserted into the expression plasmid, PGEX-4T-1, and transformed into E. coli BL21 by electric transduction. Recombinant fusion proteins of EC1-2 and EC3-4 epitopes were expressed by IPTG induction. These proteins were separated on SDS-PAGE gels and electroblotted to nitrocellulose to detect the anti-PVA antibody. RESULTS: The sequences of cloned EC1-2 and EC3-4 genes were identical to the sequence registered in PC/GENE. Expressed recombinant proteins reacted only to sera from patients with pemphigus vulgaris, not to sera from patients with bullous pemphigoid, systemic lupus erythematosus or normal persons. CONCLUSIONS: These recombinant proteins are very specific in antigenicity. This may provide a new method for the diagnosis of pemphigus vulgaris (PV) or the differential diagnosis of other bullous cutaneous diseases via patient sera. It is also helpful in understanding the relationship between adhesion molecules and the pathogenic mechanism of pemphigus vulgaris.

Autoantibodies↗
PubMed2000

[The expression of glial cell derived neurotrophic factor and its receptor GDNFR-alpha and GDNFR-beta mRNA in spinal cord, brainstem and frontal cortex during morphine withdrawal in rats].

OBJECTIVE: To investigate the expression of glial cell derived neurotrophic factor (GDNF) and its receptor GDNFR-alpha (GFRalpha-1) and GDNFR-beta (Ret) genes and the effects of muscarinic receptor antagonists, NMDA receptor antagonist, inhibitor of nitric oxide synthase on the expression of these genes in the spinal cord, brainstem and frontal cortex during morphine withdrawal, and to observe the effects of GDNF antisense oligoneucleotide (i.c.v) on the morphine withdrawal symptoms in rats. METHODS: The levels of GDNF, GDNFR-alpha and GDNFR-beta mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR) with the beta-actin mRNA as an internal control. RESULTS: The GDNF mRNA levels were increased, and GDNFR-alpha and GDNFR-beta mRNA levels was slightly increased in the spinal cord and brainstem during morphine dependence. These genes were decreased at 1 h, increased at 2 h after administration of naloxone in morphine dependent rats. While the GDNF, GDNFR-alpha and GDNFR-beta levels in the frontal cortex were increased significantly at 1, 2 and 4 h after the injection of naloxone during morphine withdrawal. The pre-treatment with L-N-nitric arginine methylester (10 mg/kg), the expressions of GDNF and GDNFR-beta in the spinal cord, both GDNFR-alpha and GDNFR-beta in the frontal cortex were decreased. The expressions of both GDNF and GDNFR-alpha in the frontal cortex were decreased by treatment with MK801 (0.5 mg/kg), and the expressions of GDNF in both the stem and cortex, and GDNFR-beta in the brainstem decreased by treatment with the methyl-scopolamine (0.5 mg/kg). The beta-actin mRNA levels were not different in each group. Moreover, the morphine withdrawal symptoms were attenuated by intracerebroven tricular injection of GDNF antisense oligoneucleotide in 6 hour and 24 hour before naloxone administration in morphine dependent rats. CONCLUSION: The results not only provide direct evidence that the expressions of GDNF and its receptors mRNA in glial cells play an important role in mediating the process of morphine dependence and may be account for the long-term neuro-adaptation associated with morphine dependence, but also suggest that muscarinic receptor, NMDA receptor and nitric oxide pathways may be involved in the expression of GDNF and GDNF receptor genes during morphine withdrawal.

Animals↗
PubMed2000

[MR urography: technique and clinical application in patients with kidney transplantation].

OBJECTIVE: To assess the value of magnetic resonance urography (MRU) for the noninvasive postoperative evaluation of renal transplants. METHODS: 28 cases of renal transplantation were examined with a modified, heavily T2-weighted fast apin-echo pulse sequence and fat-suppression pulse aid. Post-procedure processing was performed with a maximal-projection (MIP) algorithm. RESULTS: 28 patients were studied. MRU revealed abnormal finding in 9 patients: mild dilatation of the renal pelvis without any urodynamic relevant obstruction (2), moderate dilatation of the renal pelvis (3), acute rejection (3), and ATN (1). Ureteral stenosis was diagnosed in 1 patients and treated surgically. CONCLUSIONS: MRU is an alternative to conventional urinary tract images techniques. It requires no radiation or iodinated contrast material. It is reliable and noninvasive in depicting the urinary tract. MRU can be used as a noninvasive technique for assessment of renal transplantation in cases suspicious of complication in the excretory system.

Adult↗
PubMed2000

[Multiple patterns of angle closure mechanisms in primary angle closure glaucoma in Chinese].

OBJECTIVE: The mechanism of primary angle closure glaucoma (PACG) in Chinese is studied to establish a new classification system based on the etiology and mechanism of angle closure. METHODS: The anterior chamber angle's configuration and the anatomic structures related to the angle in 126 cases with PACG were observed with ultrasound biomicroscope (UBM), and the mechanisms of angle closure were analyzed by diagnostic treatment. RESULTS: Based on the configuration of the angle and anatomic structures related to the angle as well as the mechanisms of angle closure, PACG could be divided into following subtypes: pure pupillary block angle closure glaucoma [PPB, 48 cases (38.1%)]; pure non-pupillary angle closure glaucoma [PNP, 9 cases (7.1%)]; multiple mechanism angle closure glaucoma [MM, 69 cases (54.8%)]. PPB manifested that the relative position of pupillary margin was located anteriorly, the peripheral iris bombé was due to the pupillary block, and the angle closure was not related to the location and shape of the peripheral iris and ciliary body. PNP showed that the relative position of pupil margin was located posteriorly, the angle closure was not caused by the pupillary block, but caused by anterior located ciliary body and/or thick and anterior located peripheral iris. MM pattern was caused by both pupillary block and non-pupilary block, and most of the cases manifested creeping angle closure. CONCLUSIONS: The angle closure mechanisms of PACG in Chinese are of multiple patterns. Based on the different mechanisms of angle closure in PACG, a new classification system should be established to improve the diagnosis and treatment of PACG.

Adult↗