[Objective]To observe the degradation process of PDLLA in the intervertebral fusion.[Method]Twenty goats were divided into 4 groups as experimental group,and their L_(3~4)intervertebal spaces were implanted with PDLLA cage containing pieces of graft bone.Animals were sacrificed at 4,8,12,16 wks and specimens were taken for observation of the degradation process and bone fusion by gross observation and electronic microscope.Another 12 goats were used as normal fusion control group.Their L_(3~4)space were grafted with bone block for fusion.[Result]The degradation rate was non-lineal.In the early stage of fusion,the main degradation and decrease of molecular weight was shown at the superficial decomposition.With the proceeding of fusion and degradation,as the kydrolyzation speeding-up,internal decomposition by self-catalyse resulted into the collapse and total disassemble of the PDLLA.The PDLLA cage maintained its shape in the early stage and its biomechanical strength decrease in late stage but was still enough to keep the structure from collapse,till the fusion was achieved in the bone implant area.[Conclusion]The velocity of degradation of PDLLA is slower than the speed of bone regeneration of bone fusion,so the PDLLA cage could provide sufficient support during the process of intervertebal fusion and is a suitable choice of degradative material for cage in the intervertebal fusion.

Objective To evaluate the adhesion, proliferation and osteogenic differentiation of rabbits' mesenchymal stem cells (MSCs) cultured in demineralized bone matrix coated with OB-Cadherin. Method The second generation of MSC s were seeded onto the OB-Cadherin cover over allogenic frozen-dried demineralized bone matrix(FDBM) and the FDBM without OB-Cadhefin as control, and then both were cultured separably in vitro. The densities of seeded cells, the adhesion rate were measured, and their ALP activity was assayed in order to take it as an index of cell adhesion, proliferation and osteogenic differentiation. The growth and adhension of MSCs on the FDBM was observed and evaluated microscopically and electronic scanning microscopically. Data were ex-pressed as means and standard deviation (x±s), and were analyzed with SPSS 12.0. Independent-Sanples T-test and Paired t test was used, and P<0.05 indicated statistically significant. Results There was no significant dif-ference in cell proliferation between modified FDBM and unmodified FDBM cultured fot 7, 14, 21 d. ays. After culture for 20 hours, the adhesion rate in the control group was (35.56±1.75)%, the densities of seeded cells were less than 2.7×104. The adhesion rate of cells in the modified group was consistent at 80%, whereas the densities of seeded cells were as high as 5.0×105 compared with control group (P<0.01). After cultured for 20 hours, the efficiency of cell adhesion in the modified FDBM was higher than that in the unmodified FDBM. After cultured for 7 days, the cultured MSC on modified FDBM expressed higher AIP activity, and after cultured for 14 days, the ALP activity on modified FDBM was much higher than that on unmodified FDBM (p<0.01). After cultured for 14 days, osteocalcin immunohistochemical positive rate of modified group was (71±11)%, while that of the control group was(49±8)% with significant difference Conclusion OB-Cadherin enhances cell adhesion to FDBM and promotes MSC to differentiate to osteoblast, but no obvious effects d OB-Cadherin on cell proliferation were observed.

Objective To study the effects of unilateral graded facetectomy on lumbar spinal stability in biomechanics and to investigate the biomechanical characteristics of articular process and the safety of decompression produre for lumbar disc herniation.Methods The vertebral column L4/5 function spinal unit(FSU) of 5 adult cadavers was used and graded facetectomy was performed on left articular process of L4/5 resulting in 0,1/4,1/2,3/4,4/4 facetectomy of lateral small vertebral joints.The stability of each model was determined using three-dimension movement test machine of vertebral column.Results When more than 1/2 facetectomy of lateral small vertebral joints was carried out,the circuitation stability of left,right lateral flexion and the left,right axial direction of vertebral column and that of normal vertebral column had significant difference(P

Objective To explore a simple classification of the axial mastoid process and its clinical significance in improving the traditional screw insertion in the treatment of odontoid fracture with percutaneous anterior odontoid screwing. Methods The median sagittal CT images of 120 patients with cervical dis-ease were measured. They were 63 males and 57 females, aged from 31 to 59 years (average, 41.6 years). On their median sagittal CT images, line A was the connection of the lowest point of the anterior inferior boarder of the axis body to the vertex of the odontoid process and line B a parallel line to line A through the mastoid process. The distance between lines A and B was measured (the height of the axial mastoid process) and a complete statistical record was made to analyze the distribution and regularity of distances AB. The improved insertion points were indentified based on the above measurements (X25%and X75%) and clinical ex-perience. We reviewed 32 patients with odontoid fracture of Anderson&D' Alonzo typeⅡA, ⅡB or superficialⅢ. Of them 15 underwent percutaneous anterior screwing by the improved insertion points and 17 underwent percutaneous anterior screwing by the conventional insertion points. The 2 groups were compared in terms of incision length, operation time, bleeding, fluoroscopy frequency and hospital stay. Results Distance AB was 3.42 ± 0.68 mm. The distance AB <3 mm was classified as low-level mastoid process, the distance AB between 3 to 4 mm as slightly convex mastoid process, and the distance AB > 4 mm as convex mastoid process. Of the 120 patients, 32 (26.7% ) were classified as having a low-level mastoid process, 57 (47.5%) as having a slightly convex mastoid process, and 31 (25.8%) as having a convex mastoid process. Compared with the conventional insertion group, the improved insertion group had significantly shorter oper-ation time (31.32 ± 2.12 min versus 46.18 ± 3.63 min), significantly lower fluoroscopy frequency (18.20 ±1.57 times versus 21.27 ± 2.50 times) but significantly greater bleeding (43.22 ± 3.17 mL versus 31.22 ± 3.52 mL) (P <0.05). There were no significant differences between the 2 groups in incision length or hospital stay (P > 0.05). Conclusions In the treatment of odontoid fracture with percutaneous anterior odontoid screwing, the screw insertion can be improved according to our classification of the axial mastoid process. Our simple classification of the axial mastoid process may lead to more efficient operation and less radiation hazard.

BACKGROUND: Irradiation therapy in the cancer patients after surgery may have negative effects on implant fixation. OBJECTIVE: To observe the effects of 60Co irradiation and trace element zinc on fixation strengths of titanium implant. METHODS: Thirty-six adult male rabbits were involved. One piece of titanium implant was separately placed into the bilateral proximal tibial heads in rabbits to set up animal models of titanium implants. The animals were randomly divided into control group, zinc supplement group, 60Co irradiation group and 60Co irradiation and zinc supplement group. Zinc sulfate of 10 g/L was administered intramuscularly to animals in the zinc supplement group at the dose of 4 mg/kg once per day, and those in the control group were treated with saline at the same dose. The animals in the 60Co irradiation group received 60Co irradiation at the dose of 45 Gy and saline by intramuscular injection. Those in the 60Co irradiation and zinc supplement group received 60Co irradiation and zinc sulfate. The animals were killed at 1, 4 and 12 weeks after treatment. The fixation strengths were measured and compared among groups. RESULTS AND CONCLUSION: (1) Zinc supplement made the titanium implants have higher fixation strengths, and reach a high level at 4 weeks after surgery. (2) 60Co irradiation significantly inhibited the fixation strengths of the implants. After 60Co radiation, zinc supplement stil could promote fixation strengths of titanium implants. (3) It is indicated that amount of zinc supplement after irradiation therapy can al eviate the negative effects of irradiation on implant fixation.

Objective This study aimed to assess the efficiency and purification of the Trace DNA extraction with a quantified method for the magnetic bead-based DNA extraction as performed on the Tecan Automated systems with TE-MAGS magnetic separator. Methods Serial dilutions of standard commercial DNA 9947A were used with the total DNA contents, 0.1ng, 0.2ng,0.3ng, 0.4ng,0.5ng, 0.6ng, 0.7ng, 0.8ng, 0.9ng,1ng,diluted progressively and a 1ng DNA (standard commercial DNA 9947A) admixed with 6 common DNA-PCR inhibitors were extracted on the Automated systems and then performed via Fluorogenic probe quantitative PCR and STR genotype for the quantification analysis of recovery and purification. Results The recovery rate of standard 9947A DNA diluted with 0.1~1ng was 38.92~60.01%, and 0.3ng and more DNA could observed the full STR profiles. For the different PCR inhibitors, above 94.5% of bile acid, collagen and urea were efficient removal during the purification process, and the hemoglobin, melanin and humic acid removal efficiency were about 97.5%, 97.85%, 82.14%, respectively.Conclusion Our results suggested that The TE-MAGS magnetic bead-based DNA extraction was suitable for the extraction of trace DNA with high recovery efficiency and purification ability.

OBJECTIVETo discuss the risk factors of splenic arterial steal syndrome (SASS) after orthotopic liver transplantation.

METHODSTwenty-four cases who confirmed SASS after liver transplantation in Tianjin First Central Hospital between June 2005 and June 2013 were analyzed retrospectively. Another 96 cases were selected randomly from those patients of the same time with no complication of SASS patients postoperatively as control group. Clinical data of two groups including diameter of splenic artery and hepatic artery preoperatively, weight of graft, weight of recipients, cold/warm ischemia time, an hepatic period and operation time and so on were collected. Others including hepatic artery peak systolic velocity (PSV), end diastolic velocity (EDV), blood flow resistance index and portal vein average velocity (PVF) on the first day after liver transplantation, the day before diagnosis, the day when diagnosed, the 1, 3, 7 days after treatment in SASS group and on 1, 3, 7, 9, 11, 14 days after liver transplantation in control group. Statistical analysis were made between two groups.

RESULTSThe splenic artery/hepatic artery ratio preoperatively and weight of donor liver,and the GRWR in SASS group and control group were 1.26 and 1.00, 1 032 g and 1 075 g, (1.40±0.30)% and (1.82±0.21)% respectively, with significantly statistical differences (Z=-6.40, Z=-2.22, t=-6.50; all P<0.05). The warm ischemia time, the cold ischemia time, the anhepatic period and operation time in SASS group and control group were 3.5 minutes and 4.0 minutes, 10.25 hours and 10.10 hours, 43 minutes and 45 minutes, 8.7 hours and 8.7 hours, with no significantly statistical differences (all P>0.05). RI of hepatic went up gradually in the early time after transplantation while dropped obviously when spleen artery spring coils embolization was received (P<0.01) and trended to stable two weeks later.

CONCLUSIONSSplenic artery/hepatic artery ratio and GRWR are the positive and negative risk factors respectively for SASS. The gradual rising of hepatic RI in the early time after transplantation may be the warning signal SASS and spleen artery spring coils embolization is the effective strategy for SASS after liver transplantation.

Cold Ischemia ; Embolization, Therapeutic ; Hepatic Artery ; pathology ; Humans ; Liver ; surgery ; Liver Transplantation ; adverse effects ; Retrospective Studies ; Risk Factors ; Spleen ; blood supply ; Splenic Artery ; pathology ; Vascular Diseases ; epidemiology ; Warm Ischemia

Objective To evaluate the effects of early tracheostomy and late tracheostomy on the prognosis of patients with cervical spinal cord injury,so as to provide evidence based guidance for the timing of tracheostomy.Methods Relevant literatures studying the timing of tracheostomy in patients with cervical spinal cord injury were searched in PubMed,Embase,Medline,Cochrane Library,Chinese Biological Medical Literature database (CBM),China National Knowledge Infrastructure database (CNKI),and VIP journal database with time range from journal establishment to March 2018.The retrieved articles were screened according to the inclusion and exclusion criteria.The article quality was rigorously evaluated according to the Newcastle-Ottawa scale (NOS).Meta analysis was conducted using Review Manager 5.3 software to compare the mechanical ventilation time,ICU stay,incidence of pneumonia,incidence of complications,and mortality between early and late tracheostomy in patients with cervical spinal cord injury.Results A total of eight articles of cohort study including 466 patients were included,with 241 patients in the early tracheostomy group and 225 patients in the late tracheostomy group.The eight articles were all determined as high quality studies according NOS.The results of Meta analysis showed that there were significant differences between the two groups in terms of the total mechanical ventilation time (MD =-12.28,95％ CI-20.09--4.47,P ＜ 0.01),post tracheostomy mechanical ventilation time (MD =-9.92,95％ CI-14.27--5.57,P ＜ 0.01),total ICU stay (MD =-10.30,95％ CI-17.12--3.47,P ＜ 0.01),post tracheostomy ICU stay (MD =-5.79,95％ CI -6.53--5.05,P ＜ 0.01),incidence of complications (RR =0.56,95％ CI 0.38-0.83,P ＜ 0.01),and mortality (RR =0.34,95％ CI 0.15-0.78,P ＜ 0.05).However,no significant differences were detected between the two groups in the incidence of total pneumonia (RR =0.77,95％ CI 0.57-1.05,P ＞0.05) and the incidence of post tracheostomy pneumonia (RR =0.80,95％ CI 0.51-1.26,P ＞0.05).Conclusion Early tracheostomy can shorten the mechanical ventilation time,ICU stay,incidence of complications,and mortality,but it cannot reduce the incidence of pneumonia.

Objective To compare the surgical effects between minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider and open anterior ondontoid screw fixation in the treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ.Methods From July 2011 to July 2016,28 adults with odontoid fracture of Anderson-D'Alonzo type Ⅱ were treated at Department Ⅱ of Spinal Surgery,Hospital of 89 Army Group of Chinese PLA.Of them,15 were treated by minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider (guider group) while the other 13 by open anterior ondontoid screw fixation (open group).All the patients were male,aged from 31 to 59 years (average,42.7 years).The 2 groups were compared in terms of incision length,operation time,intraoperative bleeding,intraoperative fluoroscopic frequency and hospital stay.Results There were no significant differences between the 2 groups of patients in their preoperative general data,indicating they were compatible (P ＞ 0.05).All the patients were followed up for 12 to 45 months (average,22.1 months).The internal fixation was in good place and clinical union achieved in all the 28 patients.The incision length (2.2 ± 0.1 cm),operation time (45.0 ± 3.1 min),intraoperative bleeding (29.0 ± 2.3 mL) and intraoperative fluoroscopic frequency (15.5 ± 1.9 times) for the guider group were all significantly less than those (2.9 ±0.7 cm,61.6±3.8 min,51.6±3.9 mL and 21.7±3.2 times,respectively) for the open group (P ＜0.05),but there was no significant difference between the 2 groups in hospital stay (6.5 ± 0.5 d versus 6.5 ± 0.6 d) (P ＞ 0.05).Conclusion In the treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ,compared with open anterior ondontoid screw fixation,the minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider may lead to a smaller incision,shorter operation time,less blood loss and a lower fluoroscopic frequency.

Nano-drug delivery strategies have been highlighted in cancer treatment, and much effort has been made in the optimization of bioavailability, biocompatibility, pharmacokinetics profiles, and in vivo distributions of anticancer nano-drug delivery systems. However, problems still exist in the delicate balance between improved anticancer efficacy and reduced toxicity to normal tissues, and opportunities arise along with the development of smart stimuli-responsive delivery strategies. By on-demand responsiveness towards exogenous or endogenous stimulus, these smart delivery systems hold promise for advanced tumor-specificity as well as controllable release behavior in a spatial-temporal manner. Meanwhile, the blossom of nanotechnology, material sciences, and biomedical sciences has shed light on the diverse modern drug delivery systems with smart characteristics, versatile functions, and modification possibilities. This review summarizes the current progress in various strategies for smart drug delivery systems against malignancies and introduces the representative endogenous and exogenous stimuli-responsive smart delivery systems. It may provide references for researchers in the fields of drug delivery, biomaterials, and nanotechnology.