OBJECTIVE To realize the present resistance characteristics of enterococci to common antimicrobial agents,and to provide reference for clinical therapy. METHODS A total of 79 isolates of enterococci were collected from samples during the period of 2000-2003.The broth microdilution test and ?-lactamase determination were performed for each of the strains.The laboratory data were analyzed. RESULTS The rates of Enterococcus faecalis and E.faecium were 73.4%,and 26.6% of all enterococci isolates.The most common sites of infection were urinary tract(35.4%),surgical secretion(24.1%),and sputum(15.2%).The rate of E.faecium approached 50% of enterococci in urinary tract.The antibiotic resistance of E.faecium was more than E.faecalis to ampicillin,penicillin,and rifampin.The ratio of HLAR enterococci and VRE to total enterococci isolates were 61.9% and 0;?-lactamase producing rate was 6.3%. CONCLUSIONS Urinary infection caused by enterococci is most frequent.E.faecium is found more easily in urinary tract than in the others and very resistant to antibiotics.Vancomycin shows fairly high activity against enterococci.The different regimens should be adopted for different enterococci.

Objective To detect the location of histamine in peripheral sympathetic nerves of guinea pig. Methods Histidine decarboxylase mRNA was detected using in situ hybridization histochemistry with specific oligonucleotide probe,while histamine and tyrosine hydroxylase were detected using double labeled immunohistochemistry with anti-histamine antibody and anti-tyrosine hydroxylase antibody in the superior cervical ganglia of guinea pig. Results The histidine decarboxylase mRNA hybridization signal were detected in both of large and small cells.The TH immunoreactive substance distributed in cytoplasm steadly,but lacked in the nuclei,while the histamine immunoreactive substance distributed in cytoplasm nearby the plasmalemma.After chemical destroy of the guinea pig SCG′s neuron with 6-OHDA,the immunoreactive materials were hardly detected.Conclusion Because the histidine decarboxylase is the only enzyme which catalyzes histidine into histamine,histamine may be synthesized and coexisted with monoaminergic neurotransmitters in the superior cervical ganglia of guinea pig.

BACKGROUND: Hematopoietic stem cells have an ability of multi-directional differentiation and can be differentiated into megakayocytes in the presence of suitable hematopoietic growth factors and lineage special growth factors.Inducing of CD34+ stem cells to megakaryocytes in vitro involves many changes in gene expression, especially the signal transduction genes.OBJECTIVE: To study the expression of signal transduction genes after differentiation from stem cells into megakaryocytes.DESIGN: Open experiment.SETTING: Department of Tumor Immunology, Fujian Provincial Tumor Hospital.MATERIALS: 60-145 mL of cord blood was collected from normal labor fetuses under sterile conditions by using the blood-bag collective method. Patients and their relatives provided the confirmed consent. Reagents and equipments were detailed as follows: VarioMACS segregation apparatus, CD34+ Isolation Kit, SCGM serum-free medium, CD monoclonal antibodies, cytokines, human genome Oligo Set Version 2.1 from the CapitalBio Corporation, and LuxScan 10K/A bi-passage laser scanning apparatus. The researchers obtained consent from the local ethic committee.METHODS: This experiment was carried out in the Department of Tumor Immuonlogy, Fujian Provincial Tumor Hospital and the CaptialBio Corporation. from July 2005 to June 2006. RNA was extracted separately from CD34+ cells purified from cord blood and CD41+ cells induced from the same cord blood. The cDNA probes were synthesized by reverse transcription and purified. CD34+ cells before culturing and CD41+ cells after culturing were labeled with Cy3-dCTP and Cy5-dCTP respectively. Labeled DNA was dissolved in 30 μL hybridization fluid and hybridized at 42 ℃ over night MAIN OUTCOME MEASURES: The differential gene expression between haematopoietic stem cells and megakaryocytes involving cell signal transduction were detected by using DNA microarray analysis. According to the gene chip results,17 differentially expressed genes were selected for further analysis by RT-PCR.RESULTS: In this experiment, 3 522 differentially expressed genes were screened, including 1705 up-regulated genes and 1 817 down-regulated genes. In the 3 522 differentially expressed genes, there were 343 genes involved in cell signaling, 150 genes involved in transcription regulation, 21 genes involved in cell differentiation. The expression of the CD61 gene increased 369.83 fold, the expression of the CD41 gene increased 27.38 fold, and the expression of PF4 gene increased 24.06 folds; The expression of mitogen-activated protein kinases (MAPKs), G protein-coupled receptors (GPCRs) and members of RAS oncogene family increased mostly. The expression of the genes involved in STAT pathways, both SOCS1 and JAK2 were up-regulated, but STAT5A was down-regulated. As determined by the gene chip results, 17 differentially expressed genes were selected for further analysis by RT-PCR. GAPDH was used as the internal control, and RT-PCR results were in agreement and confirmed the finding from the gene chip expression results.CONCLUSION: Thrombopoeitin (TPO) and other hematopoietic growth factors may enhance the proliferation and differentiation of megakaryocytes derived from cord blood stem cells by GPCRs-Ras-MAPK pathway.

Objective To construct the eukaryotic expression vectors of fibroblast growth factor receptor 3(FGFR3) MSCV/puro-fgfr3-WT and MSCV/puro-fgfr3-DN, and to detect their expressions in human chronic myeloid leukemia(CML)K562 cell line.Methods The full-length FGFR3 (fgfr3-WT)and dominant negative FGFR3 (fgfr3-DN)were amplified by polymerase chain reaction (PCR). The two genes were respectively digested with EcoRⅠand BamHⅠ,and then ligated into MSCV/puro to construct the recombinant plasmids MSCV/puro-fgfr3-WT and MSCV/puro-fgfr3-DN which were tranduced into K562 cells by LipofectaminTM 2000 after PCR,double digestion and DNA sequencing.The expressions of FGFR3 protein in K562 cells were detected by Western blotting and flow cytometry. Results The recombinant plasmids MSCV/puro-fgfr3-WT and MSCV/puro-fgfr3-DN were amplified by PCR method, and the results showed fgfr3-WT of 2 400 bp and fgfr3-DN of 1 200 bp had been successfully cloned into MSCV-puro vector. The 2 400 bp fragment was oblained after double digestion of recombinant plasmid.The sequencing results showed that the size of fgfr3-WT was 2 400 bp which was the same as the sequence from GeneBank.Fgfr3-DN of 1 200 bp was also in conformity with the expected sequence.Compared with control (K562 MSCV)group,the expression level of FGFR3-WT in MSCV/puro-fgfr3-WT transfection (K562-WT)group was increased to above 10 times.There was high expression of FGFR3-DN in MSCV/puro-FGFR3-DN transfection (K562-DN)group,but there was no expressions in control(K562 MSCV)group and K562-WT group.The flow cytometry results showed that the high expressions of FGFR3-WT were in 57.5% cells in K562-DN group and the high expressions of FGFR3-DN were in 41.5% cells in K562-DN group. Conclusion The K562 cell lines highly expressing FGFR3-WT and FGFR3-DN are constructed successfully.

Objective To study the effects of mechanical strain on the proliferation of the human pulmonary epithelial cell and the redistribution of its membrane receptors, integrins ? 5 and ? 1. Methods A cyclic strain unit in vitro was designed. The cellular proliferative index was measured by flow cytometry and the redistribution of ? 5 and ? 1 integrins was analyzed in human pulmonary epithelial cell line H727 by laser confocal microscopy. Results The cellular proliferative index reduced significantly after cells were subjected to 15% elongation at frequencies of 20 cycles/min or 40 cycles/min for 24 h. In human pulmonary epithelial H727 cells, ? 5 and ? 1 integrins transferred from the apical layer to the basal layer and formed an adhesion plaque after 24 h exposure to 15% elongation at frequency of 40 cycles/min. Conclusion The results suggest that ? 5 and ? 1 integrins in pulmonary epithelial cells may play an important role in the transduction of mechanical stress.

Objective To study the association between the cerebral infarction and the angiotensin converting enzyme (ACE) gene rs4646994 and rs35397082 polymorphisms in Binhai area ,Tianjin .Methods Gene sequencing and DNA electrophoresis were used for the detection of the ACE gene single nucleotide polymorphisms (SNPs)(rs4646994 and rs35397082) .53 samples from pa‐tients with acute cerebral infarction and 53 samples from healthy volunteers were used in our study .Serum sample were collected from each group and tested by ACE ELISA .Results There were only deletion type of rs35397082 SNP in both of the control and cerebral infarction group .In the control group ,the number of insertion type of rs4646994 was 45(84 .91% ) ,deletion type was 8(15 . 09% ) and in the patients group ,the number of insertion was 47(88 .68% ) and the deletion was 6(11 .32% ) .There was no signifi‐cant difference between the patients group and the healthy donors (P>0 .05) .The concentration of ACE in control group was high‐er than the patients with acute cerebral infraction (P<0 .05) .Conclusion There is no significant association between the ACE gene polymorphisms(rs35397082 and rs4646994) and cerebral infarction in Binhai area ,Tianjin .The different concentration of ACE is not caused by these two SNPs .In this study ,these two SNPs are not the are not the risk factors of the cerebral infarction in Tianjin based on our study .

BACKGROUND:Silver nanoparticles (AgNPs) show strong antibacterial effect and are not easy to have drug resistance. But the antibacterial mechanisms of AgNPs have not been wel developed.
OBJECTIVE:To explain the antibacterial mechanisms of AgNPs.
METHODS:We investigated the influence of Ti, TiO2 and TiO2 containing AgNPs onEscherichia coliand Staphylococcus aureus by bacterial inhibition ring test. Escherichia coli was cultured in LB liquid medium with 0, 5, 10 mg/L AgNPs. We measured the absorbance value of bacterial culture. DNA gel electrophoresis was used to study the effect of AgNPs onEscherichia coliDNA. Then we researched the character of apoptosis on Escherichia coli by Annexin V and PI staining, using flow cytometry.
RESULTS AND CONCLUSION:The inhibiting effect of Ti and TiO2 onEscherichia coliandStaphylococcus aureus was not obvious. But the inhibition rings of TiO2 containing AgNPs to bacteria appeared. The absorbance value of Escherichia coliculture was reduced whenEscherichia coliwas co-cultured with AgNPs. And this decrease tendency was in direct proportion with AgNPs concentration. AgNPs reduced the amount of DNA of Escherichia coli and this tendency was directly proportional with AgNPs concentration. TheEscherichia coli apoptosis rate induced by AgNPs was increased and this tendency was positively correlated to the AgNPs concentration. These results indicate that AgNPs can induce bacterial apoptosis to influence the growth of bacteria.

Objective To identify and rename one strain stored in National Center for Medicine Culture Collections ( CMCC) and used for tracheitis vaccine production. Methods The test strain CMCC (B)29108 and the type strain DSM30007T were cultured on NA medium. Characteristics in morphology, physiology, biochemistry and fatty acid profile were compared between the two strains. Phylogenetic analysis was based on 16S rRNA and rpoB gene sequences, together with the DNA-DNA hybridization assay. Results A Comparative analysis of a partial sequence of the 16S rRNA gene sequence revealed that the CMCC( B) 29108 strain was closed to the Acinetobacter species and showed the highest similarity with the type strain Acinetobacter baumannii DSM30007T. Moreover, the CMCC(B)29108 strain was highly similar to type strain DSM30007T in morphology, physiology, biochemistry and fatty acid profile. On the phylogenetic tree based on 16S rRNA and rpoB gene of all Acinetobacter members, the CMCC(B)29108 strain steadily clustered into one independent branch only with the DSM30007 T strain with a DNA-DNA hybridization value of 100%. Conclusion The CMCC(B)29108 strain that is one of the strains used for the production of tracheitis vac-cine should be assigned to the species of Acinetobacter baumannii based on its phenotypic, phylogenetic and chemotaxonomic characteristics.

Objective:To analyze the clinical characteristics and SLC25A13 gene mutation in children with neonatal intrahepatic cholestasis caused by citrin deficiency(NICCD).Methods:The data of 18 children diagnosed with NICCD in Xi′an Children′s Hospital from January 2014 to December 2018 were collected.The clinical manifestations, biochemical characteristics, SLC25A13 gene mutation and prognosis were analyzed.Results:All the 18 cases of NICCD were from North China and the age of initial diagnosis averaged(63.4±19.5)days.The clinical manifestations included jaundice(100%), light yellow or white stool(38.9%), growth retardation(27.8%)and so on.All patients had cholestasis.Of 18 cases, the levels of glutamyltranspeptidase, total bile acid and alpha fetoprotein were all increased, and serum albumin was decreased.Elevated aspartate aminotransferase(94.4%), elevated glutamic pyruvic transaminase(72.2%), prolonged prothrombin time(88.9%), hyperlactemia(83.3%), hypoglycemia(77.8%), anemia(66.7%)and other biochemical abnormalities were observed.Citrulline and other serum amino acids of all cases were elevated in blood samples by tandem mass spectrometry.The increase of 4-hydroxyphenyllactate and 4-hydroxyphenylpyruvate was found in 70%(7/10)urine samples by gas chromatography.Age was negatively correlated with total bile acid( r=-0.469, P=0.049), and positively correlated with blood ammonia, threonine, methionine, ornithine and tyrosine( r=0.472, 0.690, 0.698, 0.678 and 0.769, respectively, P<0.05). A total of 16 SLC25A13 gene mutations were detected, of them c. 851_854del(33.3%)and c. 1638_1660dup(19.4%)were the most common.c.1841+ 3_1841+ 4del, c.980_981del(p.E327Vfs*45)and c. 602A>T(p.E201V)were novel mutations.Among the 17 children who were followed up, 1 case died and 16 cases had normal biochemical parameters within 1 year. Conclusion:The characteristic biochemical changes are helpful for early recognition of NICCD.The prognosis of NICCD is good if the treatment is appropriate and timely.c.851_854del and c. 1638_1660dup are high-frequency mutations of SLC25A13 gene in north China.

BACKGROUND:Bone marrow mesenchymal stem cel s have attracted widespread attention for the capabilities of self-renewal and muti-differentiation, which have been used in treatment of various diseases.
OBJECTIVE:To study the effect of three-dimensional spheroid culture system on the stemness and senescence of bone marrow mesenchymal stem cel s.
METHODS:Mesechyaml stem cel s were isolated from the bone marrow of C57/B6 mice, 3 weeks old, and cultured onto the culture plates coated with or without chitosan. After 5 days of culture, the cel phenotype and expression of stemness related markers CD44 and Sca-1 were analyzed by flow cytometry. PI and Annexin-V staining were used to detect cel apoptosis. Also,β-Gal staining was applied for identification of aging.
RESULTS AND CONCLUSION:The mouse mesenchymal stem cel s began to form spheroids on day 3. The stemness-related markers, including CD44 and Sca-1, expressed higher in spheroid mesenchymal stem cel s than the cel s under normal culturing. Compared with the normal culture group, the apoptosis and senescence of cel s from spheroid culture were lower. The results indicate that the formation of spheroids on chitosan films can increase the stemness, decrease the apoptosis and slow the senescence of mesenchymal stem cel s.