BACKGROUND:Silk fibroin, chitosan, and nano hydroxyapatite are natural materials, and they al have good biological activity and physical or chemical properties. As tissue engineering materials, they have been already widely used in clinic or research work, but there are some defects in the application of these three kinds of materials. OBJECTIVE:To discuss the preparation and characteristics of silk fibroin/chitosan/nano hydroxyapatite complicated scaffolds which could be used in bone tissue engineering. METHODS:Silk fibroin, chitosan, and nano hydroxyapatite were separately prepared into 2%solution, and then mixed at the ratio of 1:1:0.5, 1:1:1, 1:1:1.5 respectively. The three-dimensional complicated scaffolds were prepared by those mixed liquids through repeated freeze drying and chemical crosslinking technology. Scanning electron microscope was used to detect the pore size of the scaffolds. Porosity, water absorption rate, and hot-water loss rate were determined. Mechanical tester was used to measure the tensile and compressive modulus of dried three-dimensional scaffolds. RESULTS AND CONCLUSION:The silk fibroin/chitosan/nano hydroxyapatite complicated scaffold in the dry state had no special smel , appeared to be a stabilized solid cylinder, and exhibited clear resiliency and flexibility with a touch. With the increased content of nano hydroxyapatite, the porosity, water absorption rate and average pore size of the scaffolds appeared to be decreased, while the hot-water loss rate and compressive strength were increased. The scaffold prepared at 1:1:1 was better for bone tissue engineering, and the average pore size, water absorption rate and hot-water loss rate were 85.67 μm, (135.65±4.56)%and (22.84±1.06)%, respectively, closer to the needs of the bone tissue engineering. Uniform pores were found within the scaffold at 1:1:1, showing the network structure, developed transport among pores, and the network structure was approximately 10μm.

BACKGROUND:Poly lactic acid as an excellent delivery has good biocompatibility.
OBJECTIVE:To prepare recombinant human bone morphogenetic protein-2 (rhBMP-2)/poly lactic acid (PLA) sustained release microspheres, and to study its physical and chemical properties.
METHODS:The rhBMP-2/PLA sustained release microspheres were prepared using w/o/w solvent evaporation method. Scanning electron microscopy, laser particle size, zeta potential, and swel ing properties were detected. ELISA kit was utilized for measurement of encapsulation efficiency, drug-loading rate and in vitro drug release rate.
RESULTS AND CONCLUSION:Under the scanning electron microscope, rhBMP-2/PLA sustained release microspheres were approximately circle with excellent dispersion. The uniform spheres were visible with a mean particle size of 839.6 nm. The zeta potential were (-32.93±3.74) mV. The swel ing coefficient was 1.157±0.059. The drug-loading rate and encapsulation efficiency of rhBMP-2/PLA sustained release microspheres were (88.943±2.878)%and (0.026±0.001)%respectively. The drug release rate at 1 day was about 10.199%, then the drug release was relatively constant, and til 19 days, the cumulative drug release rate was 54.643%. These findings indicate that the constructed rhBMP-2/PLA sustained release microspheres meet the requirement of the Chinese Pharmacopoeia (10th edition) that the encapsulation efficiency is not less than 80%and the microspheres have a good slow-release function in vitro.

Objective To explore the influence on cyclin and cyclin-dependent kinase inhibitor of cell cycle of Kasumi-1 cell-derived from t(8;21)/AML treated with histone deacetylase(HDAC)inhibitor valproic acid(VPA).Methods RT-PCR assay was applied to detect mRNA expression of regulation factor of cell cycle of Kasumi-1 cell with VPA at different concentration and different time. Results VPA could down-regulate mRNA expression of cyclinD1,cyclinE1 and cyclinB1,and up-regulate mRNA expression of p21 WAF1/CIP1 with no obvious variation of mRNA level of p27KIP1. Condusion VPA could regulate cell cycle through the regulation of cyclins and cyclin-dependent kinase,arresting Kasumi-1 cell at G0/G1 phase.

BACKGROUND:Silk fibroin/chitosan/nano hydroxyapatite (SF/CS/nHA) composite scaffold constructed in preliminary experiments has good physical and chemical properties.
OBJECTIVE:To study the capacity and mechanism of SF/CS/nHA composite scaffold for repair of rabbit radial bone defects.
METHODS:Thirty-six New Zealand white rabbits were selected to make animal models of right radial bone defects, and then randomly divided into SF/CS/nHA group, SF/CS group and blank control group. Blank control group had no treatment after modeling. X-ray radiography, gross observation and histopathological observation were performed at 4, 8, 12, 16 weeks postoperatively.
RESULTS AND CONCLUSION:Sixteen weeks after surgery, bone defects in the SF/CS/nHA group were completed replaced by normal bone tissue on X-ray images, and the bone marrow cavity showed complete recanalization with new bone formation;hematoxylin-eosin staining showed bone trabecula and many fusiform bone cells. In the SF/CS group, the bone mineral density in the defect area was slightly lower than that of the normal bone tissues, the bone marrow cavity was partly rehabilitated, and many chondrocytes were seen around bone cells that arranged irregularly with no bone trabecula or bone lamel a. In the blank control group, the images of bone calcification were consistent with normal bone tissues, and a closed bone ununion was formed at each end;hematoxylin-eosin staining showed that the blank control group was fil ed by fibrous connective tissue and a smal amount of bone-like tissues. SF/CS/nHA composite scaffold is better for repair of rabbit radial bone defects.

Objective To determine whether nitric oxide may result in different effects on cardiac function at the different time points during the course of myocardial ischhemia and reperfusien of rats in viwo, and if so, to investigate the mechanisms involved.Methods Male adult rats were subjected to 30 minutes of myocardial ischemia followed by 5 hours of reperfusien. L-arginine was administrated at a bolus at both 10 minutes before and 50 minutes after reperfusion in early treatment group. The L-arginine was administrated at a bolus at both 3 and 4 hours after reperfusion in late treatment group. The following variables were measured: cardiac hemodynamic parameters, myocardial easpase 3 activity, iNOS and total NO content. Results Compared with vehicle group, administration of L-arginine at early reperfusion markedly reduced myocardial caspase 3 activity, and improved cardiac function. In strict contrast, administration of L-arginine at late reperfusion resulted in a significant increase in myocardial NOx content, myocardial apoptosis, and depressed the cadiac function. Conclusion Timely administration of L-arginine might inhibit apoptosis while late administration of L-arginine might enhance apoptosis.

Objective To investigate the influence of recombinant human bone morphogenetic protein‐2(rhBMP‐2)of poly lactic acid(PLA) release microspheres for compatibility of rabbit bone marrow mesenchymal stem cells(BMSCs) .Methods The rh‐BMP‐2‐PLA release microspheres were prepared by w/o/w multiple emulsion volatilizing method and then cocultured BMSCs .The effects of rhBM P‐2‐PLA release microspheres on the cytotoxicity and relative proliferation rate by MTTassay .Evaluation of mate‐rials biocompatibility by inverted microscope and scanning electron microscope(SEM) .Results The rhBMP‐2‐PLA release micro‐spheres in various concentration of leaching solution and BMSCs training of uninfected cells .Experimental group and control group in 4 different time cell proliferation OD values by analysis of repeated measurement variance between time OD values were statisti‐cally significant(P=0 .000) ,the experimental group and control group OD values are statistically significant(P=0 .025) ,the exper‐imental group higher than the control group ,experimental group OD value time there was a significant interaction effect and the group number ,the change trend are obviously different(P=0 .006) .Inverted microscope to observe materials normal cell prolifera‐tion ,SEM found that vaccination cells surrounding rhBMP‐2‐PLA release microspheres of 7 days later ,the cells grew well and split proliferation activity .Conclusion rhBMP‐2‐PLA release microspheres of BMSCs has non‐toxic and has compatibility .

BACKGROUND:Bone morphogenetic protein-2 (BMP-2) is a key to bone formation and repair.However,it has some disadvantages such as easy to lose and degrade and difficult to sustain continuous effect.OBJECTIVE:To study the preparation and properties of silk fibroin/chitosan/nano-hydroxyapatite (SF/CS/nHA) scaffold loading BMP-2.METHODS:After silk degumming,dissolution and purification,2％ SF solution was obtained.BMP-2 was dissolved in 2％ CS solution,and then fully mixed with equal volume of SF solution and proper amount of nHA.At last,the SF/CS/nHA scaffold loading BMP-2 was prepared using freeze-drying method as experimental group.The SF/CS/nHA scaffold was soaked in the BMP-2 solution as control group.The scaffold porosity was measured by Archimedes method,the surface morphology of the scaffold was observed by scanning electron microscope,the compressive strength was measured by universal testing machine.Scaffolds in the two groups were soaked in PBS,and the release of BMP-2 was measured by ELISA method at different time points.RESULTS AND CONCLUSION:(1) The scaffolds in the two groups had irregular porous structure,interconnected pores and uneven pore wall.There was no significant difference between the two groups in mean pore diameter,porosity and maximum compressive strength.(2) On the 1st day,the release rate of BMP-2 was 4.63％ in the experimental group,and the release curve increased slowly.After 28 days,the release curve of BMP-2 was transferred to the plateau stage.But in the control group,the release rate of BMP-2 on the 1stday was 58.84％,and it was a significant initial burst release.The release curve increased rapidly,and was transferred to the platform stage on the 10th day.The release rate of BMP-2 release was significantly different between the two groups at days 1,2,4,10 (P ＜ 0.05).These results show that the SF/CS/nHA scaffold loading BMP-2 could sustainably and slowly release BMP-2.

Objective To investigate the expressions of CD28 and CD117 in patients with newly diagnosed multiple myeloma (MM) and their clinical significances. Methods The clinical data of 115 newly diagnosed MM patients in the First Affiliated Hospital of Zhengzhou University from May 2015 to December 2017 were retrospectively analyzed. The expressions of CD28 and CD117 were detected by using multiparameter flow cytometry. The relationship between the expressions of CD28 and CD117 and MM staging and clinical parameters was analyzed. The staging was performed according to the International Staging System (ISS). Results Among these 115 patients, there were 15 patients with CD117 positive and 30 patients with CD28 positive. Erythrocyte sedimentation rate (r ＝ -0.481, P ＝ 0.039), Cˉreactive protein level (r ＝ -0.314, P＝0.015), the proportion of plasma cells detected by bone marrow cytology (r＝-0.027, P＝0.001) were negatively correlated with CD117 positive expressions. CD28 positive expression was positively correlated with lactate dehydrogenase level (r ＝ 0.249, P ＝ 0.033) and ISS stage (r ＝ 0.319, P ＝ 0.017), while it was negatively correlated with hemoglobin level (r ＝ -0.372, P ＝ 0.026). CD28 positive was associated with light chain type, and nonˉsecretory type mostly occurred (P ＝ 0.016). The incidence of osteolytic lesions in CD28 positive group and CD117 positive group was high, but there was no statistical difference between CD28 positive group, CD117 positive group and CD28 negative group, CD117 negative group (P ＝ 0.052, P＝0.479). Conclusions The positive expression of CD117 in the early stage of MM patients is higher than that in the advanced stage, and the expression of CD28 positive in the advanced stage of MM patients is higher than that in the early stage. CD28 and CD117 can be used as indicators of prognosis stratification in the patients with newly diagnosed MM.

Objective To survey the prevalence of greenhouse farmer's lung and related risk factors in part of rural areas of Liaoning Province.Methods Using uniform scheme,procedures and questionnaire,a survey for 5420 farmers(2660 men and 2760 women)with complete data who work inside greenhouses was performed in Shenyang,Xinmin,Chaoyang,and Jinzhou between August 2006 and June 2009.Pulmonary function tests was performed for every active farmer.Results Greenhouse farmer's lung was diagnosed in 308 cases,205 men(66.55%,205/308)and 103 women(33.44%,103/308),a prevalence of 5.7%(308/5420).The prevalence rate of greenhouse farmer's lung in males was significantly higher than that in females(?2=39.93,P0.05).In the 308 cases,the number of patiernts presented with fever chill,cough/sputum,chest tightness/shortness of breath were 180(58.44%),192(62.34%),160(51.95%)respectively,and the number of crepitations,radiological changes,spirometry abnormalities and serum IgE antibodies(+)was 164(53.25%),153(49.68%),147(47.73%)and 136(44.16%)at the time of the study.62.34%(192/308)of patients with greenhouse farmer's lung were mild and 38.66%(116/308)were severe.Conclusion The total prevalence rate of greenhouse farmer's lung in part of rural areas of Liaoning Province was 5.7% and multiple risk factors were associated with the disease.