38 patients with dentition defect in our hospital for magnetic attachment dental treatment were analyzed. At the same time,34 cases of patients with dentition defects were ,being treated with conventional prosthodontics, selected to compare the stability of overdentures and masticatory function with magnetic attachment. The stability of overdentures and masticatory function after restored with magnetic attachment was significantly higher than before(P< 0. 01),while there was no difference after 4 weeks. Cementation language,comfort and appearance satisfaction after 4 weeks were significantly higher than before(P < 0. 05). The stability of overdentures,masticatory function, cementation language,comfort and appearance satisfaction after restored with magnetic attachment was significantly higher than conventional prosthodontics(P < 0. 05). It finally indicated that magnetic attachment had the advanta-ges of comfort,convenience and good effect. The stability of overdentures,masticatory function and application sat-isfaction was superior to conventional prosthodontics,and it had an application prospect.

0.05). 6 cases of Hirschsprung′s disease showed microcolon with the appearances of shortage of colon frame, barium reflux into distal ileum and barium retention. Conclusion Local notch of the distal rectum, spiral or irregular bizarre saw-toothed contractions of the rectum and distal sigmoid colon, and delayed evacuation of barium are 3 valuable radiographic signs. Colitis itself isn′t a valuable diagnostic radiographic sign of Hirschsprung′s disease. It only shows inflammation of colon. And microcolon with the appearances of shortage of colon frame, barium reflux into distal ileum, and barium retention may suggest the diagnosis of total aganglionic colon.

BACKGROUND: Studies regarding synthesizing composite bone repair materials with organic macromolecules as mineralizers template are the hot research spot. However, reports concerning using agar as bone repair materials are few. OBJECTIVE: To synthesize a novel agar-hydroxyapatite composite material, and to evaluate its physical and chemical properties as well as cytocompatibility.METHODS: ①A certain amount of the non-nano-hydroxyapatite in hydrochloric acid solution was added into a certain amount of agar sol, and the reaction system was adjusted with PH value of 7-8. And then the precipitate was lyophilized to obtain the composite of agar-hydroxyapatite.②The third generation of rat bone marrow stromal cell (BMSC) was co-cultured with agar-hydroxyapatite. And the growth of cells was observed at days 1, 3 and 5 after culture. RESULTS AND CONCLUSION: The results of X-ray diffraction patterns, Fourier transform infrared spectrometer (FTIR), thermal analyzer, transmission electron microscope, and scanning electron microscope showed that agar could manipulate the growth of hydroxyapatite, and hydroxyapatite nanocrystals was equably formed on the agar-fibers with high porosity. The BMSC grew well in the composite and form a clear cytoskeletal at days 3 and 5 after culture. The results reveal that agar-hydroxyapatite composite has good physical and chemical properties and cytocompatibility.

OBJECTIVETo prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material.

METHODSSodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted microscope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate.

RESULTSSodium alginate-nanohydroxyapatite composite material displayed porosity, the porous pore rate was (88.6 +/- 4.5)%. BMSCs showed full stretching and vigorous growth under inverted microscope and SEM. BMSCs cultured with liquid extracts of the material had good activities. The toxicity of composite material was graded as 1. Hemolysis test results showed that the hemolysis rate of the composite material was 1.28%, thus meeting the requirement of medical biomaterials.

CONCLUSIONThe composite material fabricated in this study has high porosity and good biocompatibility.

Alginates ; Biocompatible Materials ; Cells, Cultured ; Glucuronic Acid ; Hexuronic Acids ; Humans ; Mesenchymal Stromal Cells ; Porosity ; Tissue Engineering ; Tissue Scaffolds

Objective:To obtain optimum template for randomly amplified polymorphic DNA(RAPD). Methods:Four different methods(rod winding, precipitation, boiling and lysis)for extraction of template DNA were used.The length and purity of template DNA and its RAPD profile were observed separately by agarose gel electrophoresis, spectrophotometric scan assays and RAPD reaction.Results:The template DNA (>23 kb) with high purity and the same RAPD profile with 2-4 kb DNA fragments were obtained by both rod winding and precipitation method. However,the template DNA (4 kb and 2 kb,respectively) with break and dispersion and low purity was extracted by method of boiling and lysis, and 600-2 000 bp DNA fragments were seen in the similar RAPD profile.Conclusions: Template DNA extracted by rod winding or precipitation method was optimized for RAPD.

Objective To explore the safe bone channels for transverse placement of sacroiliac screws via the second sacral vertebra in the fixation of longitudinal fracture of the sacrum by digital analysis and clinical observation.Methods Firstly,abdomen CT scanning was performed in 50 healthy adult volunteers.They were 30 males and 20 females,aged from 18 to 56 years (mean,34.6 years).After their CT images were transformed by software Materialise Mimics Innovation Suite 15.0,three-dimensional (3D) models of the pelvis were generated,stored in stereolithography format,and transferred into software Imageware 12.0.In the standard antero-posterior position,the sacrum was segmented and the points of 2D image coordinate geometric boundary were extracted to generate an optimal channel for transverse placement of sacroiliac screws via the second sacral vertebra.Secondly,we admitted 10 patients with longitudinal fracture of the sacrum.They were 7 men and 3 women,aged from 20 to 51 years (average,38.3 years).By Tile classification,4 cases were type B2 and 6 type C1.All the fractures were Denis region Ⅱ ones.Pubic ramus fracture was complicated in 3 cases.After traction reduction of the tibial tubercle was conducted for patients with obvious displacement,the optimal channel was calculated on the basis of the CT data.On the lateral images of the sacrum acquired before operation by C-arm fluoroscopy,the optimal channel for transverse placement of sacroiliac screws via the second sacral vertebra was located.After the skin was marked,2.5 mm Kirschner wire was drilled and the 6.0 mm hollow screws were fixated along the Kirschner wire.Postoperative CT scanning images and 3D reconstructed models were analyzed to validate the accuracy of screw placement.Results The projection of safety bone channel on the sagittal fluoroscopy of S2 vertebral body displayed an irregular water drop shape;the projection area in males (213.9 ± 52.4 mm2) was significantly larger than that in the females (171.6 ±49.6 mm2) (P ＜ 0.05).The average length of the channel in men (135.2 ± 12.9 mm) was significantly longer than that in women (121.1 ± 10.1 mm);the average diameter of the screw in men (10.2 ± 0.9 mm) was also significantly larger than that in women (9.1 ±0.8 mm) (P ＜ 0.05).The postoperative X-ray and CT scanning images showed satisfactory positions and lengths of the screws.The screw lengths averaged 98.2 mm;the operation time averaged 25.6 min.No nerve or vascular injury,loosening or breakage of the sacroiliac screws occurred in the patients.Follow-ups for 12 to 24 months revealed no other complications.Conclusion The safety channel for transverse placement of sacroiliac screws via the second sacral vertebra can be determined using the lateral 3D reconstruction images of the sacrum in preoperative planning,which facilitates the percutaneous transverse fixation of longitudinal fracture of the sacrum.

Objective To observe the clinical efficacy of minimally invasive percutaneous K-wire crossover fixation treating scaphoid fractures under C-arm.Methods From March 2011 to May 2014,20 patients with fresh scaphoid fractures had postoperative regular outpatient follow-up.Evaluation indicators included Cooney wrist scoring system,X-ray assessment of fracture healing,questionnaire survey of patient's subjective satisfaction at the final follow-up.Results All patients were followed up for 4 to 18 months,the mean follow-up time being 10 months.Postoperative X-ray showed all cases achieved bony union within 8 to 12 weeks,an average of 9.2 weeks.The questionaire resuits of patient's subjective satisfaction showed that general feeling of treatment in 2 cases,relatively satisfied in 2 cases,greatly satisfied in remaining 16 patients at the final follow-up.According to the postoperative Cooney wrist score,excellent in 8 cases,good in 10 cases,fair in 2 cases,the overall satisfactory rate was 90.2％.There were not pin tract infection,nonunion,malunion,avascular necrosis of scaphoid and other complications.2 cases showed that wrist pain during weight-bearing activities and weather getting cold,minor limitations of wrist function and degree of activity,grip strength slightly worse than the contralateral.Conclusions Minimally invasive percutaneous K-wire crossover fixation under C-arm combined with postoperative plaster external fixation properly can attain good clinical results in the treating of scaphoid fractures and worthy of further promotion.

OBJECTIVE To compare two different procedures of blood donation in volunteer donors,which lead to different discard rates of blood,different donation reaction rates and the satisfaction of the donor agency,so as to seek the better procedure bringing less discard of blood and more convenience for the military donor agency and blood center. METHODS In group A,3 667 donors blood was collected before the tests and retests for transfusion transmitted diseases(TTD) were done.While in group B,4 185 donors were taken blood samples for pre-donation test.The blood collection was performed 4 hours later. RESULTS In group A,3 652 units of blood were collected,of which 69 units were discarded on account of positive results in test and retest.Meanwhile,in group B 3 718 units of blood were collected from the donors who passed the pre-donation test for TTD.As a result,34 units of blood were discarded because of the positive results in retest.The discard rates of blood were 1.89% and 0.91% while the donation reaction rates were 2.22% and 3.98%,respectively.in two procedures.The discard rates of blood in group A were higher than those in group B.But the donation reaction rate in group B was higher than that in group A. CONCLUSIONS The discard rate of blood in the procedure collecting before test is higher than that in the procedure testing before collection.But the donation reaction rate is low and the waiting period for donation is short in the former procedure,which is suitable for low TTD infections population of military agencies.

Objective To explore the association between folic acid supplementation during periconcerptional period and congenital heart disease in newborns to provide scientific evidence for making intervening measures.Methods Using stratified random cluster sampling,a total of 30 counties were sampled from Shaanxi Province.A questionnaire survey was conducted among childbearing-aged women pregnant between January 2010 and November 2013.All of the included women had definite pregnancy outcomes and had signed the consent form.Logistic regression was performed to investigate the association between folic acid supplementation during pregnancy and congenital heart disease in newborns.Results In total,28 354 questionnaires were available for analysis.The overall prevalence of congenital heart disease among live-birth neonates in the present study was 7.3‰.The percentage of childbearing-age women who had taken folic acid supplementation during pregnancy was 64.4％,while only 17.2％ of them took folic acid according to the specification.Taking folic acid regularly during pregnancy was associated with a lower risk of congenital heart disease among the newborns (OR 0.502,95％ CI:0.279 0.902).The multiple-factor analysis results also showed that taking folic acid regularly during periconcerptional period could reduce the risk of congenital heart disease (adjusted OR=0.512,P=0.046) when we controlled the family background factors,mother factors and exposure risk factors during pregnancy.However,no association was found between irregularly taking folic acid during periconcerptional period and the risk of congenital heart disease.Conclusion Taking folic acid according to the specification during periconcerptional period (taking folic acid during 3 months before pregnancy to 3 months after pregnancy with a daily dose of 0.4mg for more than 90 days) may prevent congenital heart disease of newborns.

Objective To analyze the effect of special risk exposures during periconception period on birth defects of newborns.Methods From Jul.to Dec.2013,the multi-stage stratified random sampling method was adopted.Women of childbearing age between 15 and 49 who were pregnant during 2010 to 2013 in Shaanxi Province were selected as study subjects for investigation on special risk factors exposed during periconception period.The Logistic regression model was adopted to analyze the association between newborns' birth defects and special risk exposures.Results The study included 30 010 women of childbearing age and 29 550 newborns with 572 (193.57/ 10 000) cases of birth defects.After adjusting for demographic factors,the risk factors for birth defects were drinking [OR=2.29,95％ CI (1.22,4.29)] and passive smoking [OR=1.25,95％ CI (1.02,1.53)] during periconception.There was a higher risk of birth defects when exposure to medicine [OR =1.64,95％ CI (1.04,2.61)],pesticides [OR =2.41,95％ CI (1.09,5.35)],biological risk factors [OR-1.64,95％ CI (1.05,2.56)],physical risk factors [OR=1.15,95％ CI (1.13,2.34)] and chemical risk factors [OR =2.36,95％ CI (1.36,4.11)] 3 months both before and after pregnancy.Similarly,after adjusting for demographic factors and behaviors,we found that birth defects were related to antibiotics,salicylates,and antitussive,which could increase the risk of birth defects (P＜0.05).Conclusion Exposure to passive smoking and drinking during periconception and exposure to medicines and pesticides,as well as biological,physical and chemical risk factors 3 months before and after pregnancy could increase the risk of birth defects in newborns.