Study of molecular characteristics of methicillin-resistant Staphylococcus aureus in Maanshan area / 中华流行病学杂志

Objective To identity the distribution of enterotoxin and hemolysin,as well as the clonal complexes and drug resistance of the strains of methicillin-resistant Staphylococcus aureus (MRSA) in Maanshan region.Methods Automatic enzyme-linked fluorescent assay system and PCR technology were used to identify the distribution of enterotoxin and hemolysin genes.Seven Staphylococcus aureus hourskeeping genes were choosed as the target genes for multilocus sequence typing (MLST) on 34 strains of MRSA and 3 strains of methicillin-sensitive Staphylococcus aureus (MSSA),comparing the data with the online database and obtaining the sequence typing (ST),conducting affinity analysis on its ST based on eBURST,testing in agar dilution method the drug resistance of MRSA against 12 antibiotics.Results 50.9％ of the 210 Staphylococcus aureus strains were enterotoxin positive,and 97.1％ of them carried hemolysin genes as all 51 strains of MRSA carried hemolsin genes.The 34 MRSA strains were divided into 10 STs,ranging in sequence ST239 (47.1％,16/34),ST5 (17.6％,6/34).Three MSSA strains belonged to ST188,ST1281 and ST7,respectively.Seventeen strains from the patients were divided into 6 STs,ranging in sequence ST239 (35.3％,6/17) and ST5 (29.4％,5/17).Twenty strains from food sources were divided into 9 STs,ranging in sequence ST239 (45.0％,9/20) and ST7 (15.0％,3/20).STs of ST585,ST630 and ST239 were close in affinity,while the rest were distant in affinity.Except for vancomycin,all the strains were found with drug resistance to varying extent to the 10 antibiotics tested.Conclusion Existence of Staphylococcus aureus hemotoxin was universal; ST239 was the main predominant MRSA in Maanshan region,with distant affinity among the STs.

Development of both multiple PCR and real-time SYBR green PCR for the detection of Vibrio cholerae non-O1/O139 serogroups / 中华流行病学杂志

Objective To develop methodology of both multiple PCR and real-time SYBR green PCR for the detection of Vibrio cholerae (V.cholerae) serogroups non-O1 and non-O139.Methods The outer membrane protein gene (ompW) specific for V.cholerae,as well as O antigen rfb genes specific for both O1 and O139,were used for the design of the PCR primers.Both multiple PCR and real-time SYBR green PCR systems were used to detect both O1 and O139.Specific rfb genes and ompW were developed to evaluate their specificity,limit of detection,reproducibility and consistency.Results We established multiple PCR and real-time SYBR green PCR methods.According to the specific electrophoretic bands (multiple PCR) and the specific melt curve temperature (real-time SYBR green PCR),both methods could specifically detect the non-O1,non-O139 V.cholerae,and to differentiate them from O1,O139 V.cholerae,other five Vibrios and 3 intestinal bacteria.The detection limits were 7 × 104 cfu/ml (multiple PCR) and 7 × 102 cfu/ml (real-time SYBR green PCR),with statistically significant difference seen (P＜0.05).For the reproducibility of real-time SYBR green PCR,the external coefficient variation ranging from 0.22％ to 0.92％ while the internal coefficient variation ranging from 0.27％ to 1.41％.370 strains of non-O1,non-O139 V.cholerae,were detected,with both consistency rates as 100％.Conclusion Both multiple PCR and real-time SYBR green PCR could detect non-O1,non-O139 V.cholerae,rapidly,specifically,and reproducibly,that could all be used for the detection and identification of non-O 1,non-O 139 under different conditions.

Effect of statins on occurrence of infection and infection-related mortality: a meta-analysis / 南方医科大学学报

<p><b>OBJECTIVE</b>To systematically review whether statins can reduce the risk of infection and infection-related mortality.</p><p><b>METHODS</b>We searched the Cochrane Library, MEDLINE, EMBASE, PubMed, Elsevier and CBM databases for randomized placebo-controlled trials of statins published by September 2013, and each trial enrolled at least 100 participants with follow-up for at least 4 weeks. Two reviewers independently assessed the quality of the included studies and extracted the relevant data for analysis using Stata 12.0 software.</p><p><b>RESULTS</b>Sixteen trails involving a total of 48973 patients were included in our meta-analysis. The results showed that statins significantly reduced the risk of infection (OR=0.93, 95% CI 0.89 to 0.98, P=0.004) compared to placebo but did not significantly lower infection-related mortality (OR=0.96, 95% CI 0.82 to 1.12, P=0.592).</p><p><b>CONCLUSION</b>Statins can significantly reduce the risk of infection but does not lower infection-related mortality.</p>

Pasteurization affects the physicochemical properties and biological function of hemoglobin? / 中国组织工程研究

BACKGROUND:Pasteurization is a perfect method for albumin virus inactivation, which may not be required for virus inactivation validation. However, there are no systematical reports concerning virus inactivation of hemoglobin blood substitutes. OBJECTIVE:To explore the effects of pasteurization on the physicochemical properties and biological function of hemoglobin blood substitutes. METHODS:Appropriate cord blood samples were taken fol owed by centrifugation, washing blood, rupture of membranes, stabilizer treatment. In the control group, the samples were placed in 55℃water bath, and when the temperature of hemoglobin solution reached (55±1)℃, a heat treatment began and lasted for 2 hours. In the pasteurization group, the samples were placed in 60℃water bath, and when the temperature of hemoglobin solution reached (60±1)℃, a heat treatment began and lasted for 10 hours. The heating process was under continues nitrogen protection. Then, the hemoglobin solution was placed in ice bath and cooled to below 4℃fol owed by low-speed centrifugation and filtration via microporous membrane, purification and viral inactivation thereby to obtain cord blood hemoglobin. RESULTS AND CONCLUSION:The products in the pasteurization group were al red clear liquid. There was no significant difference between the two groups in the yield, methemoglobin concentration, and oxygen-carrying capacity. The purification of the two groups was more than 98%. Two kinds of purification methods had no effects on the oxygen-carrying capacity of hemoglobin. Therefore, pasteurization method can replace thermosensitive purification method of 55℃, 2 hours. The pasteurization method wil not only ensure the physicochemical and biological properties of hemoglobin, but also achieve the purpose of virus inactivation.

Roles and mechanisms of microglia activation and polarization during cerebral ischemia / 国际脑血管病杂志

Inflammation plays a key role in the secondary brain injury after cerebral ischemia,in which microglia activation and polarization play important roles.This article reviews the roles of microglia in inflammation and the molecular mechanisms of microglia activation and polarization after cerebral ischemia.

Elimination of inter-domain interactions increases the cleavage fidelity of the restriction endonuclease DraIII

DraIII is a type IIP restriction endonucleases (REases) that recognizes and creates a double strand break within the gapped palindromic sequence CAC↑NNN↓GTG of double-stranded DNA (↑ indicates nicking on the bottom strand; ↓ indicates nicking on the top strand). However, wild type DraIII shows significant star activity. In this study, it was found that the prominent star site is CAT↑GTT↓GTG, consisting of a star 5' half (CAT) and a canonical 3' half (GTG). DraIII nicks the 3' canonical half site at a faster rate than the 5' star half site, in contrast to the similar rate with the canonical full site. The crystal structure of the DraIII protein was solved. It indicated, as supported by mutagenesis, that DraIII possesses a ββα-metal HNH active site. The structure revealed extensive intra-molecular interactions between the N-terminal domain and the C-terminal domain containing the HNH active site. Disruptions of these interactions through site-directed mutagenesis drastically increased cleavage fidelity. The understanding of fidelity mechanisms will enable generation of high fidelity REases.

Effects of freeze-drying process on polymerized human placenta hemoglobin / 生物医学工程学杂志

The present study was aimed to investigate the influence of freeze-drying on the quality of polymerized human placenta hemoglobin (PolyPHb). The PolyPHb solution was freeze-drying under suitable conditions. Hemoglobin concentration, methemoglobin (MetHb) content, UV spectrum, Fe3 content, oxygen-carrying capacity, pH, the average molecular weight and its distribution, circular dichroism, oxygen equilibrium curve and other indicators were measured before and after freeze-drying. The appearance, residual water content, rehydration time of the lyophilized product were also evaluated. The results showed that there was no significant difference on all the indicators measured above, which indicated that freeze-drying process had no effect on the physical and chemical properties of PolyPHb, as well as on its biological activity. Therefore, the properties of PolyPHb were stable during this freeze-drying process and could be preserved after such freeze-drying process.

Research on optimization of polymerization process of human placenta hemoglobin / 生物医学工程学杂志

Five influencing factors of the polymerization process of glutaraldehyde with hemoglobin were studied in cluding the approach of feeding glutaraldehyde, hemoglobin concentration, the molar ratio of glutaraldehyde and hemoglobin, reaction time and temperature, in order to reduce the average molecular weight and to improve the effective polymerization ratio. The results showed that the optimal process reduced the average molecular weight of hemoglobin based oxygen carriers (HBOCs) from (350.20 +/- 35.45)kD to (158.60 +/- 8.70)kD and improved the effective polymerization ratio from 53.27% +/- 4.95% to 69.50% +/- 3.70%. When the experiments expanded 30 folds, the results of the effective polymerization ratio and the average molecular weight mentioned above could be achieved.

On the modified process of human hemoglobin based blood substitutes / 生物医学工程学杂志

Purified hemoglobin was modified with pyridoxal 5-phosphate(PLP) and polymerized with glutaric dialdehyde(GDA) to get the products. By comparison of the physical, chemical and biological properties of different procedures for modification before and after polymerization, there is no significant difference in molecular distribution, methemoglobin(MetHb) concentration, oxygen carrier capacity, P50 and spectra. Furthermore, the procedure of modification after polymerization can save PLP greatly and decrease cost greatly. So the procedure of modification after polymerization is a better way in research and production. The addition of GDA could control the increasing of MetHb. By comparison on the physical, chemical and biological properties of different procedures, there is no significant difference in molecular distribution, MetHb concentration, oxygen carrier capacity and spectra between the procedure of adding GDA before PLP and that after PLP. But the P50 of adding GDA before PLP is much lower than that after PLP. So the procedure of adding GDA after PLP is a better way.

Effect of tocotrienol rich fraction of palm oil on glucose metabolism in atherosclerotic mice / 中国药理学与毒理学杂志

AIM To investigate the effect of tocotrienol rich fraction of palm oil (TRF) on glucose metabolism in atherosclerotic mice and the possible mechanism. METHODS Apolipoprotein E gene deficient(ApoE~(-/-)) mice were divided into 3 groups as model control, TRF 0.05% and 0.2%(W/W) groups. 10% (W/W) fat and 0.2% (W/W) cholesterol were added into the diets to induce atherosclerosis formation. Oral glucose tolerance test and insulin tolerance test were conducted after mice were treated by TRF for 12 and 14 weeks respectively. Serum cholesterol, triglyceride, free fatty acid, and insulin levels were measured using corresponding kits. The mRNA expression levels for peroxisome proliferator-activated receptor γ(PPARγ), adiponectin and glucose transporter 4 (Glut4) in white adipose tissue (WAT) were determined by using quantitative real-time PCR. Activation of PPARγ by TRF was tested using luciferase reporter assays. RESULTS Compared with the model control group, TRF decreased non-fasting or fasting blood glucose levels and improved insulin sensitivity of ApoE~(-/-) mice. Both TRF groups showed decreased levels of triglyceride and free fatty acid. The mRNA level of adiponectin in WAT was up-regulated by (1.73±0.32) times in TRF 0.2% group compared with the control group. Glut4 mRNA level was increased (1.89±0.24) and (2.01±0.61) times compared with control group in TRF 0.05% group and TRF 0.2% group respectively. The fold inductions of TRF on PPARγ-ligand-binding domain, PPARγ1 and PPARγ2 activities were (2.7±0.2), (6.1±0.65) and (5.3±0.1) times compared with DMSO by using luciferase reporter assay. CONCLUSION TRF can improve glucose metabolism in atherosclerotic mice and this effect may be partly due to modulating the activity of PPARγ.

Freeze-drying of oxygen-carrying substances and storage stability of the freeze-dried solids / 生物医学工程学杂志

Oxygen-carrying substances based on poly-placental hemoglobin were put into freeze-drying. Sucrose was chosen to inhibit the methmoglobin(MetHb) formation. MetHb content, ultravioletes(UV) spectrum, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), High performance liquid chromatography (HPLC) were monitored during freeze-drying. As a result, when the mass ratio of sucrose to protein was above 0.5, MetHb formation was under control;the characteristic absorption of UV spectrum, SDS-PAGE and HPLC showed no visible change. Freeze-dried solids were kept under room temperature and refrigerator for 3 months. As a result, MetHb formation depended upon storage temperature and the mass ratio of sucrose to protein. For group C in which the mass ratio of sucrose to protein was 1.0; there is no marked change in MetHb content, UV spectrum, SDS-PAGE and HPLC after 3 months.

Current status of researches in the development of blood tissue engineering product / 生物医学工程学杂志

The term "blood substitutes" includes plasma substitutes and blood cell substitutes in the broad sense, but in its narrow sense, it means red blood cell (RBC) substitutes, platelet substitutes and white blood cell (WBC) substitutes. The RBC substitutes includes perfluorocarbon, hemoglobin-based and encapsuled substitutes. The hemoglobin-based substitutes which was widely researched in the world includes human hemoglobin-based, animal hemoglobin-based and gene recombined hemoglobin based substitutes. The function and immunology of WBC is very complicated, so it is rarely used in clinic. Nowadays the platelet substitutes pursued by the researches and developments includes mainly the liposome and collagenic fiber species substitutes.

The relevance between the effect on dysmenorrhea and the time of surgery of artery embolization in the treatment of adenomyosis / 中华妇产科杂志

Objective To analyze the relevance between the effect on dvsmenorrbea of uterine artery embolization(UAE)in treatment of adenomyosis(AM)in difierent periods of the menstrual cycle and the time of the operation.nethods Totally 225 cases with preoperative dysmenorrhea voluntarily chose UAE in treatment of AM.They were divided into two groups according to the different times of menstrual cycle(proliferative phase or secretory phase). We analyzed the relevance between the effect of dysmenorrhea of patients in the two groups with the time of surgery after 1,2,3 and4 years.Results(1)The numbers of the cases completely foilowed up were 142,128,119 and 101 each year in the foilowing four years.(2)The effective rate on dysmenorrhcainthetwo groups ofAM patientswas 81%(43/53)and 76%(68/89)after 1 year(P>0.05).(3)The effective rate was 75%(36/48)and 70%(56/80)after 2 years(P>0.05).(4)The effective rate was 70%(32/46)and 63%(46/73)after 3 years(P>0.05).(5)The effective rate was 63%(24/38)and 63%(40/63)after 4 years(P>0.05).Conclusion UAE has a good efficacy in treatment of AM,but the relevance is not significant between the time of surgery and tlle effectiveness on dysmenorrhea.