Objective To clone the mature peptide gene of seo, construct two kinds of prokaryotic fusion expression vector, obtain recombinant staphylococcal enterotoxin O(SEO) and evaluate its biological activity. Methods The seo gene was amplified from ZNZ2-3 strain of Staphylococcus xylosus by designed primers and it was cloned into fusion vector pGEX-6P-1 and pET28a. The soluble recombinant protein(GST-SEO) was expressed in E. coli BL21 host cells, the purified GST-SEO was obtained by a single step of affini-ty chromatography using Glutathinione Sepharose 4B colume. Another fusion protein(P28-SEO) with his-tag was expressed in E. coli BL21 ( DE3), the purified P28-SEO protein was harvested by nickel chelate affinity chromatography method. The antigenicity of recombinant SEO was tested by Western blot. The stimulating effects of recombinant SEO on mouse lymphocytes was tested by MTT. The activity of Caspase 3 and the ap-optosis of DNA ladder were tested. Results The nucleotide sequence of the cloned seo gene was the same as that of reported in GenBank. The soluble recombinant protein GST-SEO was expressed at 25% expression level, and P28-SEO was 22%. The Western blot by GST-SEO-positive sera demonstrated that the recombi-nant SEO had good immunogenicity. The MTY assay of the enterotoxin activity showed that low dose of re-combinant SEO stimulated the proliferation of mice spleen lymphocytes, higher doses will lead to apoptosis. Conclusion Two of the recombinant SEO still have superantigen activity, and can lead to apoptosis of mice splenocytes.

Objective:To study the influence of chloroquine combined with decitabine in the apoptosis of leukemia K562 cells and KG-1a1Aor1a cells,to explore the effect of autophagy on the leukemia cell apoptosis induced by decitabine,and to clarify its mechanism.Methods:The leukemia K562 and KG-1a1Aor1a cells were cultivated in vitro and divided into blank control group,decitabine group (10 μmol · L 1) and chloroquine (50 μmol · L 1) combined with decitabine group (combined group).The leukemia cells in combined group were pre-treated with chloroquine for 6 h before experiment.After treatment with drugs for 24 and 48 h,the number of cells was detected and by CCK-8 method the inhibitory rates of proliferation cells were calculated;the apoptotic rates and mitochondrial membrane potential were detected by flow cytometry.Q-PCR method was carried out to determine the gene expression levels of Atg7 and Atg12,and Western blotting was used to test the protein expression of LC3.Results:After treatment for 24 and 48 h,the number of K562 and KG-1a1Aor1a cells in decitabine group and combined group were decreased compared with blank control group (P＜0.05 or P＜0.01);the apoptotic rates and mitochondrial membrane potential were remarkably increased (P＜0.05 or P＜0.01).Compared with decitabine group,the number of K562 and KG-1a1Aor1a in combined group was significantly decreased,and the apoptotic rates were remarkably increased (P＜0.05).After treatment for 24 h,the expression levels of Atg7,Atg12 and LC3-Ⅱ/LC3-Ⅰ in the leukemia K562 and KG-1a1Aor1a cells in decitabine group were significantly increased compared with blank control group (P＜0.05 or P＜0.01);the expression levels of Atg7,Atg12 and LC3-Ⅱ/LC3-Ⅰ in the leukemia K562 and KG-1a1Aor1a cells in combined group were significantly decreased compared with decitabine group (P＜0.05 or P＜0.01).Conclusion:Decitabine could promote the apoptosis of leukemia cells,and the inhibition of autophagy by chloroquine can promote the apoptosis induced by decitabine.

BACKGROUND:Periprosthetic fracture of the femoral of the knee after total knee arthroplasty is one of the common complications,and there is a lack of biomechanical research on the periprosthetic fractures of the femoral of the knee under different bone strength conditions.The three-dimensional finite element analysis can provide a biomechanical basis for clinical practice. OBJECTIVE:To investigate the biomechanical changes of anterior femoral notching after total knee arthroplasty under different bone strengths,and to provide a mechanical basis for the clinical prevention of supracondylar femoral periprosthetic fractures after knee arthroplasty. METHODS:The femoral CT data of healthy adults were obtained,and the three-dimensional model of femoral lateral replacement of the knee joint was established by Mimics,Geomagic studio,and Solidworks software.Anterior femoral notching models of different depths were constructed,and the models were imported into ANSYS software to analyze the changes of biological stress on the femoral condyle with different bone strengths and different anterior femoral notching depths.The stress changes of the femoral anterior condyle section after and before the filling of anterior femoral notching with bone cement were analyzed. RESULTS AND CONCLUSION:(1)Under any bone strength,the supracondylar stress increased with the depth of anterior femoral notching.In normal bone conditions,there was a stress abrupt change point when the anterior femoral notching depth was between 3 mm and 4 mm.In the case of osteoporosis,there was a stress abrupt point when the anterior femoral notching depth was between 2 mm and 3 mm.(2)When anterior femoral notching occurred during knee arthroplasty and the depth exceeded the thickness of the bone cortex,the supracondylar stress of the femoral gradually increased as the bone strength decreased.(3)The stress of the anterior femoral condyle section decreased when the model with an anterior femoral notching depth of 3 mm was filled with bone cement.(4)The results show that anterior femoral notching should be avoided during knee arthroplasty,especially in patients with osteoporosis.If anterior femoral notching occurs during surgery,bone cement can be used to evenly fill the anterior femoral notching to reduce the supracondylar stress of the femur and reduce the incidence of periprosthetic fractures of the femoral joint

OBJECTIVETo study the protective effect of Shaoganduogan (SGDG) on serum transaminase, liver pathology and hepatocyte mitochondria in rat with subacute liver injury induced by carbon tetrachloride.

METHODSubacute liver injury of rats were induced by carbon tetrachloride, and cured by different doses of SGDG through intragastric administration. The activity of serum ALT, AST, liver pathology and ultrastructure, activity of ATPase, SOD and content of MDA of hepatocyte mitochondria were observed.

RESULTSGDG can remarkably reduce the transaminase, alleviate the degeneration and necrosis of liver cells ,enhance activity of Na+ -K+ ATPase, Ca2+ ATPase, SOD, reduce content of MDA of mitochondria, alleviate ultrastructure change of mitochondria, reduce section area, perimeter equivalent diameter and average optical density perimeter of liver cells.

CONCLUSIONSGDG has obvious effect of liver protection, the mechanisms are related with alleviating mitochondria injury.

Animals ; Carbon Tetrachloride ; adverse effects ; Chemical and Drug Induced Liver Injury ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Hepatocytes ; drug effects ; pathology ; Male ; Malondialdehyde ; metabolism ; Mitochondria ; drug effects ; enzymology ; metabolism ; ultrastructure ; Rats ; Rats, Sprague-Dawley