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Biomedical subjects

Yu Wang

Publications and source records attributed to Yu Wang.

At least 199 records · Page 11Linked to original sources
PubMed2005

[Identification of a plasmid-mediated AmpC beta-lactamase from clinical isolates of Escherichia coli and Klebsiella pneumoniae].

OBJECTIVE: To investigate the susceptibility and genotype characteristics of Escherichia coli and Klebsiella pneumoniae producing plasmid-mediated AmpC beta lactamase. METHODS: A total of 110 strains of Escherichia coli and Klebsiella pneumoniae were collected from patients hospitalized in our respiratory ward during January 2002-May 2004. The isolates harboring AmpC beta-lactamase were detected by three-dimensional test, and isoelectric focusing analysis, electroporation, PCR and DNA sequencing were performed to determine the genotypes. RESULTS: AmpC enzyme was detected in 9.30% (4/43) of the Escherichia coli isolates and 4.48% (3/67) of the Klebsiella pneumoniae isolates. The susceptibility test showed 7 isolates tested were all resistant to cefoxitin, and part of these strains were resistant to the third-generation cephalosporins, beta-lactams/beta-lactamase inhibitors, aztreonam, amikacin and ciprofloxacin, but most of them were susceptible to cefepime and imipenem. Three strains of Klebsiella pneumoniae and 2 strains of Escherichia coli transferred cefoxitin-resistance to recipients by electroporation. Results of PCR and DNA sequencing defined them to be DHA-1 AmpC beta-lactamase. CONCLUSION: Escherichia coli and Klebsiella pneumoniae producing plasmid-mediated AmpC beta lactamase were isolated from clinical strains in this hospital, and its gene can be transferred horizontally.

Bacterial Proteins↗
PubMed2005

[Analysis of peri-operative management in 1,510 patients with orthotopic liver transplantation].

OBJECTIVE: To study the clinical factors and treatment that related to early prognosis of patients after orthotopic liver transplantation (OLT), in order to improve peri-operative care and raise the survival rate in patients undergoing this operation. METHODS: Clinical records of 1,510 patients who had undergone OLT in our center were retrospectively analyzed. Twenty variables in pre-operative, intra-operative or post-operative periods were included, and several risk factors which affected the early prognosis after OLT were screened. RESULTS: With univariate analysis, the following variables showed significant difference between the survival group and the dead group: acute pathology and chronic health evaluation III (APACHE III) score, volume of transfusion and oxygen delivery (DO(2)) of tissue during operation, incidence of infection, and demand of blood purification. CONCLUSION: During peri-operative periods of OLT, combined therapy should be used, and attention should be paid to the risk factors.

Adolescent↗
PubMed2005

Middle and long-term clinical outcomes of patients with regional hepatolithiasis after subcutaneous tunnel and hepatocholangioplasty with utilization of the gallbladder.

BACKGROUND: Roux-en-Y choledochojejunostomy is routinely performed in patients with regional hepatolithiasis. However, some of these patients, who have a normal gallbladder and normal Oddi's sphincter, are unnecessarily undergoing bilio-intestinal drainage. Alternatively, reconstruction can be achieved by subcutaneous tunnel and hepatocholangioplasty with the utilization of the gallbladder (STHG). This method is effective to potential endoscopic tunnel and intervention during follow-up, and prevention of reflux cholangitis as well as the disorders of the GI tract. METHODS: The middle and long-term complications of 46 patients who underwent STHG were analyzed. With B-ultrasonography and biochemical assay, the contraction and concentration function of the gallbladder were also studied. RESULTS: Follow-up showed that all patients survived with a relatively normal life. One patient experienced right epigastric pain, chills and fever because of a stone which impacted in the left hepatic bile duct. Another patient had cholangitis because of biliary ascariasis. The two patients were treated by endoscopic therapy within the subcutaneous gallbladder under local anesthesia. CONCLUSIONS: This operation not only keeps the normal physical functional of the gallbladder, Oddi's sphincter and gastrointestinal tract, but also prevents reflux cholangitis and the disorder of the digestive tract. Hence STHG is a novel operation dealing with regional hepatolithiasis.

Adult↗
PubMed2005

[A kind of method for time-frequency analysis of electrocardiosignal imitation].

Electrocardiosignal (ECG) is an important evidence base for the diagnoses of cardiovascular diseases as well as for the researches in basic and clinical medicine. Because it presents typical non-steady signals, the wave in time can not reflect the essential characteristic very well. In this article, by analysis in time-frequency domain, we have obtained some typical time-frequency diagrams of normal ECG and abnormal ECG, which reflect the comparatively essential characteristics of the original signal in some aspects and seem likely to become a basis for validating the relevant diagnosis.

Algorithms↗
PubMed2005

[A case-control study on JWA promoter -76G-->C polymorphism and the susceptibility of bladder cancer].

OBJECTIVE: This case-control study was aimed to detect the single nucleotide polymorphisms (SNPs) in JWA promoter region, to assess the effect of SNP on transcriptional activity, and to probe the relationship between SNP and the risk of bladder cancer. METHODS: The design of one control per case was adopted. The JWA gene promoter region in 155 patients with bladder cancer and in 155 cancer-free controls was amplified by PCR-SSCP technique, and the SNP were confirmed by direct DNA sequencing. The recombinant plasmids of JWA promoter fragment which contain the SNP were constructed as CAT reporter gene and were transfected transiently into NIH 3T3 cells for disclosing whether SNP changes the transcriptional activity of the promoter. RESULTS: A novel SNP -76 G-->C at promoter region of JWA gene was found. The frequencies of the C allele and GC genotype at JWA promoter -76G-->C in bladder cancer group (10.00% and 20.00% respectively) were significantly higher than those in control group (5.16% and 10.32% respectively) (P < 0.05). The transcriptional activity of -76GC allele genotype was significantly down-regulated as compared with that of -76GG allele genotype (P < 0.01). Multivariate logistic regression analysis revealed that JWA polymorphism at promoter -76G-->C is an independent novel risk factor for bladder cancer. CONCLUSION: The JWA -76G-->C variant genotype may play an important role in transcription regulation of JWA gene and in the susceptibility to bladder cancer.

Aged↗
PubMed2005

[Experimental study of Raman spectra of magnesite at 297 K and at the pressure of 0.13-1 GPa].

The experimental study of Raman spectra of magnesite has been conducted at the pressure of 967 MPa and at the temperatureof 297 K using a cubic zirconia-anvil cell. The result shows that neither phase transition nor organic substances were observed during compression, and the Raman peak of magnesite shifted to higher frequency with increasing pressure. The relation between the pressure and the Raman peak position of magnesite (1094 cm(-1)) was obtained as follows: v (cm(-1)) = 0.007 44 x P(MPa) + 1 093.3. The value of dv/dP of magnesite is greater than the previous data obtained by Gillet, which was mostly taken under the mantle pressure. And at the ambient temperature, magnesite can be used as a pressure gauge, and the relation between the pressure and Raman shift of 1 094 cm(-1) peak position is given as following: P(MPa) = 125.8 x (deltavp) 1094 + 124.7 (1094 cm(-1) < vp < 1101 cm(-1)).

Algorithms↗
PubMed2005

[Effects of iptakalim on intracellular calcium concentrations, PKA and PKC activities in rat tail artery smooth muscle cells].

AIM: To investigate the effects of iptakalim, a new structural potassium channel opener (KCO), on intracellular calcium concentration ([Ca2+]i), protein kinase C (PKC), and cAMP-dependent kinase (PKA) activities in rat tail artery smooth muscle cells (RTA-SMC), and to analyze mechanisms involved in iptakalim reversing hypertensive vascular remodeling. METHODS: RTA-SMC was cultured and passages 3-4 were used for experiment. [Ca2+] i was measured by laser scanning confocal microscope after loaded with fluorescent indicator fluo-3-acetoxymethylester, and activities of PKA and PKC were detected by commercial assay kits (the nonradioactive PepTag system) following instructions. RESULTS: Compared with baseline, [Ca2+] i reduced significantly after iptakalim- or pinacidil-treatment at concentrations of 0.1, 1 and 10 micromol x L(-1), while diazoxide caused significant decrease at concentration of 1 and 10 micromol x L(-1). After preincubation with 1 micromol x L(-1) glibenclamide, [Ca2+] i was not significantly changed when iptakalim, pinacidil or diazoxide were added at concentration of 0.1 and 1 micromol x L(-1). Activities of PKA and PKC increased significantly by 1 micromol x L(-1) iptakalim- or pinacidil-treatment, while 1 micromol x L(-1) diazoxide induced significant change in activity of PKC but not in that of PKA. CONCLUSION: The characteristics of iptakalim on [Ca2+] i, PKA and PKC are more or less similar to those of pinacidil. Iptakalim decreased [Ca2+] i while increased PKA and PKC activities of RTA-SMCs, which may contribute to its ability to reverse antihypertensive vascular remodeling.

Animals↗
PubMed2005

[The expression of 11 cancer/testis (CT) antigen genes in esophageal carcinoma].

OBJECTIVE: To investigate the expression status of 11 different cancer/testis (CT) antigen genes in esophageal carcinoma. METHODS: Esophageal carcinoma tissue and adjacent normal esophageal mucosa taken from 35 esophageal carcinoma patients were assayed for the expression of 11 different CT antigen genes by RT-PCR techniques. RESULTS: Of the 11 CT antigen genes analyzed, none of them was expressed in normal esophageal mucosa. MAGE-3 was found to be the most frequently expressed in esophageal carcinoma tissues (62.9%), followed, in the order of expression frequency, by MAGE4 (31.4%), LAGE-1 (28.6%), MAGE-1 (25.7%), CT10 (20.0%), NY-ESO-1 (20.0%), CT7 (5.7%) and SCP1 (2.9%). No expression of SSX-1, SSX-2 and SSX-4 was found. Among the 35 cases, 28 (80.0%) expressed at least one CT antigen gene, 21 (60.0%) expressed more than 2 CT antigen genes, and 4 of the 21 (19.0%) expressed more than 4 CT antigens, which accounted for 11.4% of total number of patients (4/35). No CT antigen expression was found in the tumor tissue in 7 cases, including 5 cases in stage II and 1 case each in stage I and IV, respectively. Of the 11 CT genes examined, expression of 5 genes (NY-ESO-1, LAGE-1, MAGE-1, MAGE-3 and MAGE-4) was correlated with tumor progression. SCP-1 and CT10 expression was found more frequently in early stage patients. With progression of the disease, the frequency of co-expression of multiple CT antigen genes was significantly increased reaching 28.6% in stage III patients. CONCLUSION: Of the 11 different CT antigen genes examined by RT-PCR in esophageal carcinoma, 8 genes were detected in various frequencies in 28 of the 35 esophageal cancer patients studied. They are candidate tumor-associated antigens in the preparation of tumor vaccines for immunotherapy in esophageal cancer patients.

Adult↗
PubMed2004

Vibrational spectroscopic studies of (3-mercaptopropyl)trimethoxylsilane sol-gel and its coating.

Organosilane sol-gels have been prepared under different conditions from mercaptopropyltrimethoxysilane (MPTMS) and mercaptopropyltriethoxysilane (MPTES). These sol-gels were applied for the thin film coating on aluminum. Vibrational spectroscopy has been employed to trace and to study the proceeding of the sol-gel formation and the curing of the coated films on Al. Based on the group frequencies as well as their spectral behavior under different conditions, vibrational assignments have been made for most of the observed bands. Surface enhanced Raman scattering has revealed the chemical adsorption of MPTMS sol-gel on silver particles. Recorded reflection and absorption infrared (RAIR) spectra of coated tiles cured at different temperatures have indicated that surface reaction may occur at high temperature. The anticorrosion characters of the coated metals have been evaluated with the measured electrochemical data. Results from cyclic voltammographs have indicated that each layer of sol-gel coating would reduce the redox current across the electrode/electrolyte solution interface. Tafel plots have shown that the anodic current of the coated electrode decreases significantly and the corrosion potentials shift to the positive side.

Electrochemistry↗
PubMed2004

Fetal cells in mother rats contribute to the remodeling of liver and kidney after injury.

Fetal microchimerism indicates a mixture of cells of maternal and fetal origin seen in maternal tissues during and after pregnancy. Controversy exists about whether persistent fetal microchimerism is related with some autoimmune disorders occurring during and after pregnancy. In the current experiment, an animal model in which EGFP positive cells were taken as fetal-origin cells was designed to detect the fetal microchimerism in various maternal organs. Ethanol drinking and gentamicin injection were adopted to induce liver and kidney injury simultaneously. EGFP positive cells were engrafted not only in the maternal circulation and bone marrow, but also in the liver and kidney as hepatocytes and tubular cells, respectively. These results indicate that fetal cells are engrafted to maternal hematopoietic system without apparent injury and they also contribute to the repairing process of maternal liver and kidney.

Animals↗
PubMed2004

Characterization of a specific phage-displayed Peptide binding to vasculature of human gastric cancer.

Antivascular therapy provides a promising method for anticancer therapy. But targeting to gastric cancer vessels is nonselective due in part to the lack of specific cell-surface receptors identified on target vascular cells. Herein we used in vivo screening of phage displayed peptide library to identify some peptides that bind selectively to endothelial cells of human gastric cancer rather than nonendothelial cells. After four rounds of selection, one phage was obtained with a cyclic 7-mer peptide CGNSNPKSC homing to human gastric adenocarcinoma . There was a 4.6 approximately 137.26-fold increase in the number of the selected phage in gastric cancer xenograft in comparision with control organs brain, heart, liver, spleen and kidney. Immunohistochemistry in mouse and human tissue showed that this phage peptide only bind to the endothelial cells of human gastric cancer. This peptide was observed only specific binding to HUVEC not to SGC-7901, Eca-109, LoVo and Hep-G2 by ELISA. The competitive and inhibitory result between the synthetic CGNSNPKSC peptide and the phage displaying the peptide CGNSNPKSC on HUVEC and in vivo was also confirmed its specific binding effect. This peptide may be a possible candidate for targeted drug delivery in antivascular therapy.

Angiogenesis Inhibitors↗
PubMed2004

[Expression of NY-ESO-1/LAGE-1 genes in hepatocellular carcinoma and autologous humoral responses induced thereby].

OBJECTIVE: To investigate the potential of utilizing NY-ESO-1/LAGE-1 antigens in hepatocellular carcinoma (HCC) vaccines. METHODS: RT-PCR method was used to detect the expression of NY-ESO-1/LAGE-1 mRNA in the cancerous tissues and adjacent tissues resected from 34 patients with HCC. ELISA assay was adopted to analyze the NY-ESO-1 specific antibodies in 37 serum samples of HCC patients, 1 positive control sample, and 8 samples of normal persons. RESULTS: Nine (26.5%) out of the 34 HCC samples were NY-ESO-1 mRNA positive, while 12 (35.3%) were LAGE-1 positive. Among them, seven HCC samples expressed both genes, and 14 (41.6%) expressed at least one of the genes. Among the 37 serum samples tested six contained high titer of anti-NY-ESO-1 antibodies. Five of the samples were from stage III or later stage HCC patients; one was from a stage II patient. CONCLUSION: NY-ESO-1/LAGE-1 mRNA is expressed in a high frequency in HCC tissue samples, and induces autologous humoral responses in HCC patients. Both of the antigens can be considered as candidates for HCC vaccines.

Antibodies, Neoplasm↗
PubMed2004

A new series of pyrimidine-containing linear molecules: their elegant crystal structures and intriguing photophysical properties.

A new series of aza-substituted analogues 3-5 based on the 1,4-bis(phenylethynyl)benzene moiety have been synthesized by the selective Pd-catalyzed Sonogashira coupling reaction from 5-bromo-2-iodopyrimidine (1). In these linear molecules, the dipolar pyrimidine moiety is introduced as a probe to investigate factors that control the intermolecular interactions over the crystal engineering. The results reveal that the manner of packing changes both dipolar interactions between linear pyrimidine-containing molecules and transition moments simultaneously, resulting in remarkably different photophysical properties. Due to their versatile dipole-dipole and face-to-face pi-piinteractions in a crystal motif, further applications on the design of ordered crystalline materials for the field effect transistors are promising.

Journal Article↗
PubMed2004

Cancer/testis antigen expression and autologous humoral immunity to NY-ESO-1 in gastric cancer.

Gastric cancer has the highest mortality rate and the second-highest morbidity rate of all malignant tumors in China. Since cancer/testis (CT) antigens are expressed in various types of human tumors but generally not in normal tissue except for testis, they are promising antigens for cancer immunotherapy. NY-ESO-1, in particular, is the most immunogenic of the CT antigens. To study the feasibility of developing a CT antigen vaccine for gastric cancer, 101 gastric cancer samples were analyzed for the presence of NY-ESO-1 mRNA and that of 10 other CT antigen genes. Twelve out of 101 samples (11.9%) were found to be NY-ESO-1 mRNA-positive, 11 of them from advanced stage patients. In 7 of the 12 NY-ESO-1 mRNA-positive samples, the NY-ESO-1 protein was also detected by immunohistochemistry. An autologous humoral immune response to NY-ESO-1 was detected in 6 of 12 advanced stage NY-ESO-1 mRNA-positive patients, indicating that NY-ESO-1 is immunogenic in advanced stage gastric cancer. The serum from a patient with an NY-ESO-1 negative but LAGE-1 positive tumor was also found to be NY-ESO-1 antibody positive, possibly due to cross-reactivity between NY-ESO-1 and LAGE-1. All NY-ESO-1 mRNA-positive gastric cancer samples also expressed one to seven additional CT genes, revealing a tendency toward a clustered expression pattern, regardless of disease stage. About 74% of the samples expressed at least one CT antigen, most frequently MAGE-3 (41.6%). NY-ESO-1 and MAGE-3 are thus potential targets for a multivalent CT antigen vaccine.

Antibody Formation↗
PubMed2004

Hepatic differentiation capability of rat bone marrow-derived mesenchymal stem cells and hematopoietic stem cells.

AIM: To investigate the different effects of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) on hepatic differentiation. METHODS: MSCs from rat bone marrow were isolated and cultured by standard methods. HSCs from rat bone marrow were isolated and purified by magnetic activated cell sorting. Both cell subsets were induced. Morphology, RT-PCR and immunocytochemistry were used to identify the hepatic differentiation grade. RESULTS: MSCs exhibited round in shape after differentiation, instead of fibroblast-like morphology before differentiation. Albumin mRNA and protein were expressed positively in MSCs, without detection of alpha-fetoprotein (AFP). HSCs were polygonal in shape after differentiation. The expression of albumin signal decreased and AFP signal increased. The expression of CK18 was continuous in MSCs and HSCs both before and after induction. CONCLUSION: Both MSCs and HSCs have hepatic differentiation capabilities. However, their capabilities are not the same. MSCs can differentiate into mature hepatocyte-like cells, never expressing early hepatic specific genes, while Thy-1.1(+) cells are inclined to differentiate into hepatic stem cell-like cells, with an increasing AFP expression and a decreasing albumin signal. CK18 mRNA is positive in Thy-1.1(+) cells and MSCs, negative in Thy-1.1(-) cells. It seems that CK18 has some relationship with Thy-1.1 antigen, and CK18 may be a predictive marker of hepatic differentiation capability.

Animals↗
PubMed2004

Effects of nNOS antisense in the paraventricular nucleus on blood pressure and heart rate in rats with heart failure.

Using neuronal NO synthase (nNOS)-specific antisense oligonucleotides, we examined the role of nitric oxide (NO) in the paraventricular nucleus (PVN) on control of blood pressure and heart rate (HR) in conscious sham rats and rats with chronic heart failure (CHF). After 6-8 wk, rats with chronic coronary ligation showed hemodynamic and echocardiographic signs of CHF. In sham rats, we found that microinjection of sodium nitroprusside (SNP, 20 nmol, 100 nl) into the PVN induced a significant decrease in mean arterial pressure (MAP). SNP also induced a significant decrease in HR over the next 10 min. In contrast, the NOS inhibitor N(G)-monomethyl-L-arginine (L-NMMA, 200 pmol, 100 nl) significantly increased MAP and HR over the next 18-20 min. After injection of nNOS antisense, MAP was significantly increased in sham rats over the next 7 h. The peak response was 27.6 +/- 4.1% above baseline pressure. However, in the CHF rats, only MAP was significantly increased. The peak magnitude was 12.9 +/- 5.4% of baseline, which was significantly attenuated compared with sham rats (P < 0.01). In sham rats, the pressor response was completely abolished by alpha-receptor blockade. HR was significantly increased from hour 1 to hour 7 in sham and CHF rats. There was no difference in magnitude of HR responses. The tachycardia could not be abolished by the beta(1)-blocker metoprolol. However, the muscarinic receptor antagonist atropine did not further augment the tachycardia. We conclude that NO induces a significant depressor and bradycardiac response in normal rats. The pressor response is mediated by an elevated sympathetic tone, whereas the tachycardia is mediated by withdrawal of parasympathetic tone in sham rats. These data are consistent with a downregulation of nNOS within the PVN in CHF.

Adrenergic alpha-Antagonists↗
PubMed2004

Effect of insulin on hyperkalemia during anhepatic stage of liver transplantation.

AIM: To investigate the effectiveness of insulin on decreasing serum potassium concentration during anhepatic stage of orthotopic liver transplantation. METHODS: Sixteen patients with serum potassium concentrations greater than 4.0 mmol/L at the onset of anhepatic stage were randomized into two groups. The patients in control group (n = 8) received no treatment, while those in treatment group (n = 8) received an intravenous bolus injection of regular insulin (20 U) 10 min into the anhepatic stage, followed by a glucose infusion (500 mL 50 g/L dextrose) over 15 min. RESULTS: In control group, potassium concentration underwent no changes whereas in treatment group, it decreased from 4.8+/-0.48 mmol/L to 4.19+/-0.55 mmol/L (mean+/-SD) within 15 min and to 3.62+/-0.45 mmol/L 60 min after the therapy. The potassium concentration was lower in treatment group than in control group within 30 min of treatment (3.94+/-0.57 vs 4.47+/-0.42 mmol/L, respectively; P<0.05), and increased similarly 30 s after graft reperfusion in both groups of patients, but remained lower in treatment group (5.81+/-1.78 vs 7.44+/-1.75 mmol/L, respectively; P<0.05). The potassium concentration returned to pre-reperfusion levels within 5 min after graft reperfusion. CONCLUSION: In patients undergoing orthotopic liver transplantation, the administration of insulin rapidly decreases serum potassium concentration even in the absence of the liver, suggesting an important contribution by extrahepatic tissues in insulin-stimulated uptake of potassium.

Adult↗