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Biomedical subjects

Lei Zhang

Publications and source records attributed to Lei Zhang.

At least 253 records · Page 14Linked to original sources
PubMed2005

[Screening for phenanthrene-degrading bacteria and its characteristics].

One bacterial strain, designated as Phx1, was isolated from Daqing oil-field with the method of sublimate-plate and determination of dioxygenase activity. Phxl can degrade phenanthrene (100microg/mL, in LB media) completely in 24 h. Compared to MSM, LB and broth media can accelerate the phenanthrene degradation, promote the degradation of intermediates especially. With the method of plasmid elimination, it was proved that the genes encoding for degradation of phenanthrene locate on the larger one of the two plasmids. According to morphological and physio-biochemical characteristics, Phxl was identified as Agrobacterium sp. and was probably a new species of the genus Agrobacterium due to its 16S rDNA sequence which has the similarities of 97.8 % and 96.6% to Agrobacterium tumefaciens UP-3 and Agrobacterium albertimagni respectively.

Biodegradation, Environmental↗
PubMed2005

[A preliminary study of CTGF in bleomycin-induced mouse pulmonary fibrosis].

AIM: To investigate CTGF's role in bleomycin-induced pulmonary fibrosis. METHODS: Kunming mice were intratracheally administered with bleomycin to establish pulmonary fibrosis model. The expression of CTGF was studied by immunohistochemical method and RT-PCR. The degree of fibrosis was evaluated by pulmonary hydroxyproline assay. RESULTS: CTGF protein and mRNA were not expressed in normal mice. However, they were detected in pulmonary fibrotic mice from day 7 after bleomycin treatment, and increased as fibrosis developed (P <0.01). CTGF protein's expression was correlated with hydroxyproline content in lung tissue (r=0.92, P <0.01). CONCLUSION: CTGF plays a role in pulmonary fibrosis. Detection of CTGF may be an early and sensitive marker for evaluating the occurrence and development of pulmonary fibrosis.

Animals↗
PubMed2005

[Measurement of monoamine transmitters in the brains of ovariectomized mice using high performance liquid chromatography with fluorescence detection and gradient flow rate elution].

A method for the determination of norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in brains of ovariectomized mice was established by using high performance liquid chromatograph with a fluorescence detector, a C18 column and a gradient flow rate delivered by a single pump. The mobile phase was a mixture of 0.1 mol/L KH2PO4 and CH3OH (9/1, v/v). Detection limits of the method were determined to be lower than 10 nmol/L, absolute recoveries were above 80% and the relative standard deviations (RSDs) of intra-day were all within 3.03%. The method has the advantages of high sensitivity and of simple sample preparation. Short analysis time and better separation of samples were also obtained.

Animals↗
PubMed2005

[Relationship between plasma brain natriuretic peptide concentration and clinical prognosis in patients of acute myocardial infarction].

OBJECTIVE: To evaluate the value of brain natriuretic peptide (BNP) in estimating risk stratification in patients with acute myocardial infarction (AMI) and to determine the relationship between BNP and adverse cardiac events after AMI. METHODS: The 135 subjects were selected into the study, including 25 healthy subjects and 110 patients with a first AMI. The plasma concentrations of BNP were measured at two to four days after infarction in patients and healthy controls. Left ventricular function was evaluated by echocardiography with the parameters of left ventricular ejection function (LVEF) after 3 months. Patients were followed up at 12 months. The main outcome measures were heart failure, left remodeling, mortality and other adverse cardiac events at one year. RESULTS: Plasma BNP concentrations in patients with AMI were much higher than those in the health control people (416.7 +/- 208.0 ng/L versus 61.8 +/- 34.1 ng/L, P < 0.01). The BNP count ranged from 5 to 2500 ng/L in AMI patients. There was no association between the BNP count and mortality rate. The development of new congestive heart failure (CHF) was associated with a higher BNP count (P = 0.02). The development of any of the clinical end points (death/CHF/shock) occurred more frequently in patients with a higher BNP count (13.8% for BNP count of < 100 ng/L, 39.1% for BNP count of 100 - 200 ng/L, 43.3% for BNP count of 200 - 400 ng/L, 46.4% for BNP count of > 400 ng/L; P = 0.019). Plasma BNP concentrations remained independently associated with the development of clinical end points in multivariable model that adjusted for potential confounding variables. CONCLUSION: The results of the present study confirm that the elevated BNP count related to the risk stratification and prognosis in patients with AMI. Elevations in BNP count are associated with a higher incidence of new CHF and adverse clinical outcomes after AMI. It could serve as a strong predictor for the subsequent development of poor outcomes in AMI patients.

Adult↗
PubMed2005

[A retrospective study on the association of sexual behavior during pregnancy with intrauterine infection of hepatitis B virus].

OBJECTIVE: Case-control study was employed to explore the association of sexual behavior during pregnancy and hepatitis B virus (HBV) intrauterine infection. METHODS: 212 HBsAg positive pregnant women were consecutively collected and investigated as objects. Those neonates detected for HBsAg with S/N value > or = 5 by Abbott reagents in periphery sera were selected as cases, others as controls. Information on sexual behavior during pregnancy, maternal HBeAg status and other factors was collected, and were analyzed with univariate analysis, multivariate logistic regression analysis, etc, to explore the association of factors with HBV intrauterine infection. RESULTS: Ten of the 214 neonates were validated as occurrence of HBV intrauterine infection. Sexual behavior in the second trimester during pregnancy, with odd ratios 9.15 (95% CI: 1.10 - 76.28), as well as maternal positivity for HBeAg and HBV DNA, was significantly associated with HBV intrauterine infection, and sequently affirmed by multiple logistic regression analysis. The strength of association increased with frequency of sexual behavior. Interaction analysis suggested that there was synergistic interaction between maternal positivity of HBeAg and sexual behavior in the second trimester. CONCLUSION: Sexual behavior was a newly discovered risk factor for HBV intrauterine infection, which need to be estimated in future studies. Inhibition of virus replication and moderate control of sexual behavior would be helpful to prevent HBV intrauterine infection.

Case-Control Studies↗
PubMed2005

[Study on the molecular epidemiology of Stenotrophomonas maltophilia infection in patients on mechanical ventilation].

OBJECTIVE: To investigate a potential outbreak of Stenotrophomonas maltophilia (pma) infection occurred in patients on mechanical ventilation in a respiratory ICU (RICU) and to track the infective origins by antibiotype and pulsed-field gel electrophoresis (PFGE) typing methods. METHODS: (1) Thirteen pma strains were isolated from 9 patients on mechanical ventilation (9 strains), hand swabs of medical staffs in RICU (2 strains) and fiberscope used for intubations and aspiration (2 strains) from December, 2002 to February, 2003. (2) Sixteen strains gathered from different wards during the period of 1997 - 2000 were collected and used as control. (3) Antibiotic susceptibility data of all strains were collected. (4) Homology of the strains was analyzed by the methods of antibiotype and PFGE genotype. RESULTS: Of the 9 pma isolated from patients on mechanical ventilation, eight had identical PFGE genotype. The isolates from two RICU staffs and two fiberscope displayed the same genotype with the eight patients above. Seven of the 9 isolates shared an identical antibiotype. The consistent rate of antibiotype with PFGE genotype was 85% (11/13). There were 11 PFGE genotypes and 9 antibiotypes in 16 strains of the control group, which indicated that they came from different clones. CONCLUSIONS: Eight pma strains of patients in RICU came from the same clone. This result proved that clone transmission occurred in patients on mechanical ventilation. Contaminated fiberscope and hands of staffs may be the infective origin and the route of transmission.

Bacterial Typing Techniques↗
PubMed2005

Retrospective analysis of 472 Chinese children with chronic idiopathic thrombocytopenic purpura: a single center experience.

We retrospectively analyzed the clinical characteristics and management of 472 Chinese children (age 1~14 years) with chronic idiopathic thrombocytopenic purpura (ITP). The distribution of cases by age showed a maximum at 4 years and more patients below 7 years old than between 7 and 14 years old had ITP (337, 71.4% vs. 135, 28.6%). Variable bleeding signs occurred in this series of patients. Steroids therapy was effective for Chinese children with chronic ITP whether as first- or second-line therapy. Traditional Chinese medicine was less effective than steroids.

Adolescent↗
PubMed2005

[Effects of high dose glucose-insulin-potassium infusion on myocardial injury and serum sFas/ sFasL concentration in acute myocardial infarction].

OBJECTIVE: This study was designed to evaluate reperfusion therapy, co-administered with high dose glucose-insulin-potassium (GIK) treatment on serum soluble Fas/APO-1 (sFas) and Fas ligand (sFasL) concentration in Acute Myocardial Infarction (AMI) patients. METHODS: Seventy-four patients with AMI underwent reperfusion therapy were randomized into GIK group (n = 35) receiving high-dose GIK for 24 hours or a vehicle group (n = 39). Thirty-four control subjects (NC) were also enrolled in the present study. Strepavidin-biotin ELISA was used to determine the serum sFas and sFasL concentration at baseline and different time point (24 h, 3 d, 7 d and 14 d) after reperfusion. RESULTS: (1) The serum concentration of sFas and sFas-L ([sFas] and [sFas-L]) of AMI patients were significantly elevated at baseline as compared with NC (P < 0.01). (2) The [sFas] in GIK and non-GIK group decreased 24 h after reperfusion (P < 0.01 vs. baseline) and then increased during 3-7 d period (P < 0.01 vs. 24 h). (3) The GIK group demonstrated reduced [sFas] at 14 d (P < 0.01 vs. 7 d), with no concomitant changes in the non-GIK group. (4) The [sFasL] in the GIK and non-GIK group were no significant difference during 3-14 d period. CONCLUSION Owing to cardioprotective effects reported here and by others, a high-dose GIK infusion co-administered with the timely establishment of perfusion should be strongly considered as a treatment of choice for AMI.

Adult↗
PubMed2005

[Hydrolysis and mechanism of wastewater contained protein using immobilized protein enzyme].

Protein-enzyme was immobilized on big-hole resin, activated charcoal and silica particles by a absorption method. This study focuses on effect of enzyme immobilization, thermal stability and hydrolysis efficiency of wastewater. The result of batch test show that the ratio of immobilized enzyme on activated charcoal, big-hole resin and silica particles was 61.95%, 37.85% and 20.31% respectively. The highest of thermal ability of activated charcoal, big-hole resin and silica particles was 18.68 mg/min, 21.48 mg/min and 3.6 mg/min respectively at pH 5.5. The total amino-acids of big-hole resin and activated charcoal immobilized enzyme after hydrolysis was respectively increased to 21.26 times and 14.6 times. The kind of amino-acid was increased from 14 to 16 kinds. The continuous-flow test result indicate that concentration of substrate in influent had significant effect on the hydrolysis rate of immobilized enzyme reactor. The reactor was able to gain hydrolysis rate of 80% for protein and 36.1% (VFA/COD%) for organic materials in the wastewater with a moderate concentration of protein (500 mg/L). The ethanol and acetic of volatile hydrolysis-mixture composition were 50.3% and 33.3% respectively.

Enzymes, Immobilized↗
PubMed2005

[Effect of elastic pivot stable bite plate on treating irreducible temporal bone displacement of the temporomandibular joint].

OBJECTIVE: To investigate the effect of elastic pivot stable bite plate on treating irreducible temporal bone displacement of the temporomandibular joint. METHODS: Twenty-eight cases of irreducible temporal bone displacement of the temporomandibular joint treated with the elastic pivot stable bite plate from 2000 to 2004 were summarized. The ages of the patients ranged from 15 to 58 years including 11 men and 17 women. RESULTS: All the patients were treated for 1 month and followed up for 3 to 6 months. The effective rate was 87.51%. The patients who had shorter course of diseases obtained better effect than the patients who had longer courses of diseases. CONCLUSION: Elastic pivot stable bite plate is an effective alternative for treating irreducible temporal bone displacement of the temporomandibular joint and it exerts better effect on the patients that have short courses of diseases.

Adolescent↗
PubMed2005

[Inhibitory effects of transfected Bcl-XL antisense oligodeoxynucleotide on proliferation of esophageal cancer cells and growth of human esophageal carcinoma in nude mice].

OBJECTIVE: To investigate the biologic effects of Bcl-XL antisense oligodeoxynucleotide (ASODN) transfected into cultured esophageal carcinoma cells and human esophageal carcinoma xenograft in nude mice. METHODS: Cationic liposome-mediated ASODN was used to transfect esophageal carcinoma cells. RT-PCR, Western blot, MTT assay, flow cytometry and in-situ apoptosis cells detection (TUNEL detection) were used to systematically study the biological effects of the transfected cells in vitro and in vivo. RESULTS: MTT assay showed that the proliferation of esophageal carcinoma cells in the ASODN group decreased significantly as compared with control (P < 0.05), along with a 57.3% inhibitory rate of Bcl-XL mRNA, a significant decrease of Bcl-XL protein and the apoptosis rates of (31.1 +/- 5.8)% and 35.0% by flow cytometry and TUNEL assay, respectively (P < 0.01, as compared with controls). The growth of human esophageal carcinoma in nude mice was also significantly inhibited in the ASODN group (P < 0.05), along with a significant decrease of Bcl-XL mRNA and protein expression, and also an enhanced apoptosis of the tumor cells in nude mice. CONCLUSIONS: Bcl-XL ASODN can effectively inhibit the proliferation of esophageal carcinoma cells in vitro and the growth of the tumor in vivo. The suppression of Bcl-XL expression by ASODN may offer both a therapeutic approach and an important theoretic foundation for gene therapy against esophageal carcinoma.

Animals↗
PubMed2005

[Management of blood vessels in the vascularized autogenous submandibular gland transfer for severe keratoconjunctivitis sicca].

OBJECTIVE: To summarize the management of blood vessels in the transfer of vascularized autogenous submandibular gland. METHODS: Sixty-eight cases of vascularized transfer of autogenous submandibular gland for severe keratoconjunctivitis sicca performed from August 1999 to April 2004 were reviewed. Data collected for each patient included general items, donor and recipient vessels, vessel crisis, salvage of the vessel thrombosis, and survival of transferred glands. RESULTS: Among the 68 cases, all the donor and recipient arteries were facial artery and superficial temporal artery respectively. For donor veins, 55 were facial veins, 1 was vein near the duct, and 12 were venae comitantes of facial artery. For recipient veins, 62 were superficial temporary veins and five were veins in the upper neck, one was deep temporary vein. Vessel thromboses occurred in 10 cases, 9 were venous and 1 were arterial. The salvage rate was 10.0%, with the overall survival rate of 86.8% of transferred gland. CONCLUSIONS: Variation in venous outflow is common in microvascular transfer of submandibular gland, and anastomosis between venae comitante of facial artery and superficial temporal vein is most dependable. Vessel anastomosis under microscope may reduce the vessel thrombosis rate after operation.

Adolescent↗
PubMed2005

[Relationship between expression of Smad and ventricular remodeling after myocardial infarction in rats].

OBJECTIVE: To investigate the relationship between expression of Smad3, Smad7 and ventricular remodeling in rats after myocardial infarction. METHODS: Myocardial infarction was induced by left anterior descending coronary artery ligation in rats (n = 11) and sham-operated rats were used as control (n = 10). The rats were sacrificed 8 weeks later. Heart weight/body weight (HW/BW), mean blood pressure, left ventricular end diastolic pressure (LVEDP), collagen content in the un-infarcted area were examined. The mRNA levels of transforming growth factor (TGF)beta(1), Smad 3, Smad7 were determined by RT-PCR. RESULT: Compared with controls, the level of HW/BW, LVEDP and collagen content were significant increased. The mRNA expression of TGFbeta(1) and Smad3 was significantly increased in areas of myocardial infarction, border of the infarction, interventricular septum and right ventricle. The expression of Smad7 mRNA in these areas was decreased. CONCLUSION: These results indicated that TGFbeta(1)-Smads signaling was correlated to the ventricular remodeling after myocardial infarction. Smad3 might promote the process while Smad7 inhibit the process.

Animals↗
PubMed2005

Effect of nitric oxide on toll-like receptor 2 and 4 gene expression in rats with acute lung injury complicated by acute hemorrhage necrotizing pancreatitis.

BACKGROUND: Toll-like receptor (TLR) 2/4 might play important roles in mediating proinflammatory cytokine synthesis and release. And nitric oxide (NO) has been used to treat acute respiratory distress syndrome (ARDS). This study aimed to investigate the changes in TLR2/4 gene expression in the lungs of rats with acute lung injury (ALI) complicated by acute hemorrhage necrotizing pancreatitis (AHNP) and the effect of NO on the TLR2/4 gene expression. METHODS: One hundred and ten SD male rats were randomly divided into sham-operated group (n=10), AHNP group (n=30), chloroquine-treated group (n=30), and L-Arg-treated group (n=40). The lungs were dissected for lung histological scoring, and bronchoalveolar lavages were harvested for lung injury indexing. TLR2/4 mRNA expression in the lungs was measured by RT-PCR. RESULTS: TLR2/4mRNA was detected in the lungs with low values in the sham-operated group (0.016+/-0.210E-2, 0.112+/-0.750E-2), but it was markedly increased at 3 hours in the AHNP group (0.787+/-0.751E-2, 1.512+/-1.794E-2), peaking at 12 hours (1.113+/-6.141E-2, 2.957+/-2.620E-2; P<0.05 or P<0.01). When lung injuries were aggravated, TNF-alpha concentrations in the lungs were increased, but NO concentrations were decreased (P<0.05 or P<0.01). When TLR2/4mRNA was inhibited by CQ (3h: 0.313+/-5.491E-2, 0.005+/-1.419E-3; 6h: 0.488+/-7.442E-2, 0.010+/-1.518E-3; 12h: 0.883+/-8.911E-2, 0.024+/-2.760E-3; P<0.05 or P<0.01), lung injuries were relieved. NO concentrations in the lungs were increased but TNF-alpha concentrations were decreased (P<0.05 or P<0.01). When the rats with AHNP were treated with L-Arg, TLR2/4mRNA expression in the lungs could be effectively inhibited (50 mg-T: 0.656+/-3.977E-2, 1.501+/-6.111E-2; 100 mg-T: 0.260+/-0.891E-2, 0.732+/-5.135E-2; 200 mg-T: 0.126+/-0.914E-2, 0.414+/-1.678E-2; 400 mg-T: 0.091+/-0.399E-2, 0.287+/-0.176E-2;P<0.05 or P<0.01) and lung injuries were relieved. At the same time, NO concentrations in the lungs were markedly increased, but TNF-alpha concentrations were decreased (P<0.05 or P<0.01). CONCLUSIONS: The expression of TLR2/4mRNA is increased in the lungs in rats with AHNP and lung injuries are aggravated.TLR2/4mRNA gene expression of the lungs of rats with AHNP could be markedly inhibited by NO, leading to the relief of lung injuries.

Animals↗
PubMed2005

Value of bilirubin oxidase and its mutants in the diagnosis of hyperbilirubinemia.

OBJECTIVE: To elucidate the significance of the coordination amino acid residues in bilirubin oxidase (BO) and their kinetic characteristics, and evaluate whether BO mutants may serve as better diagnostic agent for hyperbilirubinemia. METHODS: The BO mutants I402G and C457S were obtained by site-directed mutagenesis and confirmed by amino acid sequence analysis. Ru-incorporated C457S mutant was obtained by direct incubation of ruthenium compounds with the mutant. The electron paramagnetic resonance (EPR) spectra of the recombinant BO and the mutants were investigated, and the enzyme kinetics of the recombinant BO and I402G mutant were measured with bilirubin as the substrate at 25 degrees C. RESULTS: The BO mutants were expressed and purified successfully. The mutant I402G showed low enzyme activity, and had C457S virtually no enzyme activity. Nevertheless Ru-incorporation conferred higher enzyme activity to C457S mutant. The enzyme kinetic investigations revealed that the kinetic parameter k(cat) of the recombinant BO and I402G mutant was 235.8 min(-1) and 6.9 min(-1), respectively, suggesting higher enzyme activity of the recombinant BO. CONCLUSIONS: The coordinating amino acids have important significance in maintaining the integrity of active centers and enzyme activities of recombinant BO and its mutants. The enzyme activities of the mutants I402G and C457S are much lower than those of recombinant BO, therefore they are not appropriate for diagnostic purpose. Ru-incorporation facilitates the formation of a new intact active center in C457S mutant, which therefore acquires enzyme activity.

Aspergillus oryzae↗
PubMed2005

Degradation of dyestuff wastewater using visible light in the presence of a novel nano TiO2 catalyst doped with upconversion luminescence agent.

A new upconversion luminescence agent, 40CdF2 x 60BaF2 x 0.8Er2O3, was synthesized and its fluorescent spectra were determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks shown in the fluorescent spectra whose wavelengths are all below 387 nm under the excitation of 488 nm visible light. This upconversion luminescence agent was mixed into nano rutile TiO2 powder by ultrasonic and boiling dispersion and the novel doped nano TiO2 photocatalyst utilizing visible light was firstly prepared. The doped TiO2 powder was charactered by XRD and TEM and its photocatalytic activity was tested through the photocatalytic degradation of methyl orange as a model compound under the visible light irradiation emitted by six three basic color lamps. In order to compare the photocatalytic activities, the same experiment was carried out for undoped TiO2 powder. The degradation ratio of methyl orange in the presence of doped nano TiO2 powder reached 32.5% under visible light irradiation at 20 h which was obviously higher than the corresponding 1.64% in the presence of undoped nano TiO2 powder, which indicate the upconversion luminescence agent prepared as dopant can effectively turn visible lights to ultraviolet lights that are absorbed by nano TiO2 particles to produce the electron-cavity pairs. All the results show that the nano rutile TiO2 powder doped with upconversion luminescence agent is a promising photocatalyst using sunlight for treating the industry dye wastewater in great force.

Azo Compounds↗