Real-time fluorescent quantitative PCR assay for measuring cytomegalovirus DNA load in patients after haematopoietic stem cell transplantation.
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Biomedical subjects
Publications and source records attributed to Lan-juan Li.
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BACKGROUND: Automated immunoassay analyzers are used to identify hepatitis B virus (HBV) serum markers. In regions with high prevalence of HBV, it is imperative to compare test results from different immunoassay analyzers. METHODS: Samples from 496 subjects were collected and HBV markers were determined (double-blind, parallel manner) using Abbott AxSYM, Roche Modular Analytics E170, and Abbott Architect i2000). RESULTS: Concurrence between AxSYM and E170 was 97.78% for HBsAg, 91.13% for anti-HBs, 98.79% for anti-HBc, 98.39% for HBeAg, and 88.91% for anti-HBe. Positive rates of anti-HBs and anti-HBe from AxSYM were lower than E170 (P<0.01). Concurrence between AxSYM and Architect i2000 was 98.79% for HBsAg, 91.33% for anti-HBs, 95.97% for anti-HBc, 98.39% for HBeAg, and 95.77% for anti-HBe. Positive anti-HBs rates from AxSYM were lower than Architect i2000 (P<0.01). Concurrence between E170 and Architect i2000 was 97.38% for HBsAg, 94.15% for anti-HBs, 95.56% for anti-HBc, 99.60% for HBeAg, and 88.10% for anti-HBe. Positive anti-HBe rates using Architect i2000 were lower than E170 (P<0.01). Overall, the greatest differences were observed in samples with low-level serum HBV markers. CONCLUSION: Significant discrepancies were observed among results for the 3 automated immunoassay analyzers, especially for low-level anti-HBs and anti-HBe results.
OBJECTIVE: To identify the aminoglycoside resistance gene in the high-level gentamicin resistant (HLGR) enterococcus and its transmission mechanism. METHODS: A HLGR strain, HZ95, of Enterococcus casseliflavus was screened by agar dilution method. The aminoglycoside activation enzyme genes were screened by PCR. The PCR products underwent purification, cloned, and sequenced. Plasmids were extracted and underwent Southern hybridization. Plasmid-mediated aminoglycoside modifying enzymes were cloned. The resistance of the HZ05 strain to different antimicrobial agents was determined by K-B method or agar dilution method. RESULTS: A new aminoglycosides-modifying enzyme, APH (2'')-Ie, leading to HLGR, was found in the plasmid of the HZ95 bacteria. The aph (2'')-Ie gene and partial sequence of a streptomycin adenylyltransferase gene (str) were contained in the 8.7-kb cloned fragment, and the transposase gene (tnpA) was on the upper stream. The aph (2'')-Ie gene was located on the 16-kb plasmid with the amino acid sequence 96.1% homologous with chromosome-mediated APH (2'')-Id aminoglycoside-modifying enzyme. CONCLUSION: HLGR can be caused by a new plasmid-mediated aminoglycosides-modifying enzyme, APH (2'')-Ie, which can be transmitted among plasmids or chromosome with other resistant genes through transposase.
OBJECTIVE: To determine the antibiotics resistance, aminoglycoside-modifying enzymes and homology of high-level gentamycin resistant enterococcus in clinical specimens. METHODS: The high-level gentamicin resistant (HLGR) isolates were screened by the agar method and the resistance of 14 antimicrobial agents was determined by K-B method. The aminoglycoside-modifying enzyme genes were detected by polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) was used to analyze the homology of HLGR isolates. RESULTS: The ratio of HLGR was 64.2% (68/106). Among the HLGR,there were no isolates resistant to linezolid, vancomycin and tecoplanin, and Enterococcus faecium was more resistant to beta-lactam antibiotics and quinolone than Enterococcus faecalis. The positive rate of aac(6')-Ie-aph(2')-Ia was 92.6% and 3 isolates had the resistance gene mostly similar to aph(2')-Id. And among 51 HLGR isolates from the hospitalized patients, PFGE grouped 17 E. faecalis isolates into 4 clusters (A-D), and 33 E. faecium isolates into 8 clusters (A-H) with A cluster as predominant. CONCLUSION: HLGR has become the important antibiotic resistance bacteria which results in nosocomial infection; and aac(6')-Ie-aph(2')-Ia is the main aminoglycoside-modifying enzyme gene which causes HLGR.
OBJECTIVE: To explore the role played by HBV antigen specific cytotoxic lymphocytes (CTLs) in severe hepatitis B patients. METHODS: Three kinds of HBV specific CD8+ T cells responding to HBV core 18-27, polymerase 575-583 and envelope 335-343 specific CD8+ T cells were searched with major histocompatibility complex (MHC)-peptide tetramer flow cytometry in the patients we studied. The cytokines produced by these specific CTLs such as IFNgamma, TNFalpha, IL-4, IL-10 were detected using ELISPOT assays. Their ability to lyse target cells was analyzed using a CytoTox96 Non-Radioactive Cytotoxicity Assay kit (Promega). RESULTS: The number of HBV core 18-27 specific CD8+ T cells was significantly higher in the peripheral blood of acute severe hepatitis B group patients than that in chronic severe hepatitis group (P less than 0.05), but lower than that in the acute hepatitis B patients. The IFNgamma and TNFalpha levels of acute severe hepatitis B patients were both significantly higher than those in the chronic severe hepatitis group (P less than 0.05). The ability to lyse target cells of HBV core 18-27 CTLs was also significantly higher in the acute severe hepatitis B group than that in the chronic severe hepatitis B group (P less than 0.05). CONCLUSION: The response to antigen stimulation was much higher in acute severe hepatitis B than in chronic severe hepatitis B patients. The specific CTLs persisted among the peripheral blood mononuclear cells in acute severe hepatitis B, which may be related to the viral clearance.
OBJECTIVE: To clone the gene of plasmid-mediated AmpC beta-lactamase from the plasmid of multiple-drug resistance Klebsiella pneumoniae producing plasmid-mediated AmpC beta-lactamase and demonstrate its mechanism of transmission. METHODS: Plasmids of the transconjugant were extracted and digested with restriction endonuclease HindIII. Taq DNA polymerase was applied to fill the recessed 3' termini, and a single deoxyadenosine was added to the 3' termimi of fragments. Then these fragments were ligated with pGEM-T Easy vector. E. coli DH5alpha containing recombinant plasmid was selected on MacConkey agar plates containing ampicillin and cefoxitin. Insert fragments were sequenced by primer walking. MIC determinations and isoelectric focusing electrophoresis (IFE) were utilized to analyze recombinant. RESULTS: The recombinant plasmid pT948 containing a 5.2-kb insert was obtained. The inserted fragment contained a bla(DHA-1) and a regulatory gene ampR. The insertion sequence (IS26), qacEDelta1 and sulI genes of the I type integron were obtained near the bla(DHA-1) gene. Recombinant expressed a beta-lactamase with pI of 7.7. MIC determinations showed that recombinant was resistant to cefoxitin and the resistance to ceftazidime could be induced by the cefoxitin. CONCLUSION: The plasmid-mediated ampC gene cloned was identified as bla(DHA-1). IS26 observed on the flanks of the bla(DHA-1) maybe relate to the translocation of bla(DHA-1) gene region from the chromosome to plasmid.
OBJECTIVES: To investigate the intestinal microflora status related to ischemia/reperfusion (I/R) liver injury and explore the possible mechanism. METHODS: Specific pathogen free grade Sprague-Dawley rats were randomized into three groups: Control group (n=8), sham group (n=6) and I/R group (n=10). Rats in the control group did not receive any treatment, rats in the I/R group were subjected to 20 min of liver ischemia, and rats in the sham group were only subjected to sham operation. Twenty-two hours later, the rats were sacrificed and liver enzymes and malondialdehyde (MDA), superoxide dismutase (SOD), serum endotoxin, intestinal bacterial count, intestinal mucosal histology, bacterial translocation to mesenteric lymph nodes, liver, spleen, and kidney were studied. RESULTS: Ischemia/reperfusion increased liver enzymes, MDA, decreased SOD, and was associated with plasma endotoxin elevation in I/R group compared to those in the sham group. Intestinal Bifidobacterium and Lactobacillus decreased and intestinal Enterobacteria and Enterococci, bacterial translocation to kidney increased in the I/R group compared to the sham group. Intestinal microvilli were lost, disrupted and the interspace between cells became wider in the I/R group. CONCLUSION: I/R liver injury may lead to disturbance of intestinal microflora and impairment of intestinal mucosal barrier function, which contributes to endotoxemia and bacterial translocation to kidney.
OBJECTIVE: To evaluate the clinical efficacy and study the mechanism of combining plasma exchange and continuous veno-venous hemofiltration in treating patients with chronic severe viral hepatitis B in their mid- and late stages. METHODS: 94 patients suffering from chronic severe viral hepatitis B were divided into three groups. 29 patients were treated with plasma exchange plus continuous veno-venous hemofiltration (group A). 31 patients were treated with plasma exchange alone (group B). 34 patients received routine treatment (group C). The efficacy of treatment and survival rate of the three groups was investigated. Before and after artificial liver support system treatment the levels of cytokine were examined. RESULTS: In group A, hyponatremia improved, the levels of interleukin 8 (IL-8) obviously decreased, the level of IL-10 increased, 5 of the 10 patients in coma regained normal consciousness (50.0%) and their survival rate was 48.3%. In group B, hyponatremia did not change, the level of IL-8 and IL-10 did not change. 2 of 11 patients in coma regained normal consciousness (18.2%) while survival rate was 22.6%. In group C, 1 of 11 patients in coma regained normal consciousness (9.1%) while survival rate was 20.6%. CONCLUSIONS: It shows that plasma exchange with continuous veno-venous hemofiltration in treating patients with mid- and late stage chronic severe viral hepatitis B can increase the survival rate. IL-8 can be significantly removed, IL-10 significantly increased. This combined therapy is easy to practice, and should be used as an artificial liver support system.
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OBJECTIVE: To study the effect of Gardenia-Aweto compound (GAC) and two component on preventing acute respiratory distress syndrome (ARDS) by the rabbit model of ARDS induced by intravenous injection of oleic acid. To detect the efficiency component of GAC in preventing ARDS. METHOD: GAC was divided into two compounts, ethanol-soluble components (ESC) and ethanol-deposition components (EDC), based on polarity. Forty-three new zealand rabbits were randomly divided into five groups, the blank control group, the model group, the GAC groups, the ESC group, and the EDC group. The ARDS model was induced by intravenous injection of oleic acid. Dynamic changes of arterial blood gas, lung index, albumin in bronchoalveolar lavage fluid (BALF) in different groups and lung histological changes were observed and compared. RESULT: As compared with the blank group, in the model group, GAC group, ESC group, EDC group the arterial PO2 and oxygen saturation deprived continuously. While SO2 in GAC group at time points 30, 60, 90, 120 min (P < 0.05 or 0.01) and SO2 in ESC group at time points 30, 60, 90 min were higher than those in ARDS group. PO2 in ESC group at time points 30, 60 min (P < 0.05) were higher than those in ARDS group. The value of LI and W/D were higher in ARDS group than in sham group (P < 0.01), they were much lower in HD group than in ARDS group (P < 0.01). Concentration of BALF-albumin increased markedly in ARDS group and pre-treatment groups compared with sham group, but it was much lower in GAC group and ESC group, there was a significant difference between GAC group (P < 0.01), ESC group (P < 0.05) and ARDS group. The lung histological changes had been improved in GAC group and ESC group. But no significantly difference between above-mentioned parameters was found in comparison in the model group and in the EDC group. CONCLUSION: Preventive administration of GAC or ESC an protect the damaged lung function in ARDS rabbits induced by oleic acid. The efficiency component of GAC in preventing ARDS is ESC. GAC antagonizing ARDS may relate to its anti-inflammatory, immuno-modulatory, anti-oxidant and antithrombotic effects.
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OBJECTIVE: To study the association between hepatitis B virus (HBV) mutants and the pathogenesis of severe hepatitis B by full-length HBV genome. METHODS: Serum samples from 10 severe hepatitis B patients were collected in our hospital. Serum HBV DNAs were extracted using DNA mini Kit, and amplified by LA Taq DNA polymerase to yield full-length HBV DNA. PCR products were isolated and cloned into vector pUCm-T, then transfected into DH-5 alpha cells. Positive clones were selected and checked by digestion, and full-length HBV DNAs were sequenced. RESULTS: 4 cases were cloned into vector pUCm-T successfully and completed the full-length sequencing. Among them, 3 cases had a G to A mutation at nucleotide 1896 in pre-C region and 1 had a double mutation of T1762-A1764 in the core promoter region. Some amino acid changes occurred within the known CTL, B or T cell epitopes of the PrS2 and C regions. CONCLUSIONS: This method could serve to study the relationship between HBV genome and the pathogenesis of severe hepatitis B.
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BACKGROUND: SARS-CoV is the causative agent of severe acute respiratory syndrome (SARS) which has been associated with outbreaks of SARS in Guangdong, Hong Kong and Beijing of China, and other regions worldwide. SARS-CoV from human has shown some variations but its origin is still unknown. The genotyping and phylogeny of SARS-CoV were analyzed and reported in this paper. METHODS: Full or partial genomes of 44 SARS-CoV strains were collected from GenBank. The genotype, single nucleotide polymorphism and phylogeny of these SARS-CoV strains were analyzed by molecular biological, bioinformatic and epidemiological methods. RESULTS: There were 188 point mutations in the 33 virus full genomes with the counts of mutation mounting to 297. Further analysis was carried out among 36 of 188 loci with more than two times of mutation. All the 36 mutation loci occurred in coding sequences and 22 loci were non-synonymous. The gene mutation rates of replicase 1AB, S2 domain of spike glycoprotein and nucleocapsid protein were lower (0.079% - 0.103%). There were 4 mutation loci in S1 domain of spike glycoprotein. The gene mutation rate of ORF10 was the highest (3.333%) with 4 mutation loci in this small domain (120 bp) and 3 of 4 loci related to deletion mutation. By bioinformatics processing and analysis, the nucleotides at 7 loci of genome (T:T:A:G:T:C:T/C:G:G:A:C:T:C) can classify SARS-CoV into two types. Therefore a novel definition is put forward that according to these 7 loci of mutation, 40 strains of SARS-CoV in GenBank can be grouped into two genotypes, T:T:A:G:T:C:T and C:G:G:A:C:T:C, and named as SARS-CoV Yexin genotype and Xiaohong genotype. The two genotypes can be further divided into some sub-genotypes. These genotypes can also be approved by phylogenetic tree of three levels of 44 loci of mutation, spike glycoprotein gene and complete genome sequence. Compared to various strains among SARS-CoV Yexin genotype and Xiaohong genotype, GD01 strain of Yexin genotype is more closely related to SARS-CoV like-virus from animals. CONCLUSION: The results mentioned above suggest that SARS-CoV is responding to host immunological pressures and experiencing variation which provide clues, information and evidence of molecular biology for the clinical pathology, vaccine developing and epidemic investigation.
OBJECTIVE: To investigate the dynamic variability of intestinal flora and endotoxins in rats with fulminate hepatic failure. METHODS: Establishing the fulminate hepatic failure models by intraperitoneal injection of Galactosamine. Forty Sprague-Dawley rats were divided into three groups: group A (n=10) were killed at the beginning of the experiment as control; while Group B (n=12) and C (n=18), the fulminate hepatic failure models, were killed 24 and 48 hours respectively after successful induction. Then, the contents of the jejunum, ileum and colon descendents were collected and a quantitative analysis was made about intestinal flora. Meanwhile, the concentrations of endotoxin in portal vein and right ventricle were determined and so were those in contents of ileums and colons. RESULTS: Our experiments showed that the livers of rats in group B were injured most seriously among three groups, and a minor recovery of hepatic function was observed in group C with the decrease of total bile acids (P< 0.05). Analysis on intestinal flora show: the intestinal enterobacteriacea increase and the lactobacillus decrease in group B (P< 0.01 in jejunum and ileum and P<0.05 in colon). The comparisons between group C and B showed that the enterobacteriacea in the former decreased in both jejunum and colon (P< 0.05) while the number of lactobacillus recovered in the jejunum of group C (P<0.05). Quantitative analysis on endotoxins showed that the ileum endotoxin increased in group B (P< 0.05) and in group C, endotoxins in ileum and colons also increased (vs. control, P<0.01); portal endotoxin in group B showed higher level than that in group A and C (P< 0.01). CONCLUSION: The alteration of intestinal flora was observed in fulminate hepatic failure rats. Abnormal intestinal flora might lead to incline of endotoxin in ileum, colon and portal vein, while the recovery of normal intestinal flora would decrease the level of portal endotoxin.
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