BACKGROUND:With increasing freeze-drying time,the water content of allogeneic bone reduces along with the bone mechanical strength.The suitable dehydration degree that maintains mechanical strength of allogeneic bone and allows long-term preservation at room temperature remains controversial.OBJECTIVE:To detect the mechanical properties of bovine bone nail following different degrees of dehydration using the three-point bending mechanics tests.DESIGN,TIME AND SETTING:Biomechanical analysis,comparative observation.The experiment was performed at the Mechanical Laboratory of Southern Medical University between May 2007 and May 2008.MATERIALS:Bone nails,50 mm length and 3 mm diameter,made from healthy adult bovine femoral cortical bone were divided into control and freeze-drying groups (8,12,24 hours,respectively) with 20 samples in each group.METHODS:The water content of bone nails with or without freeze-drying was measured by SH10A Moisture Quick Determination Meter.Three-point bending mechanics tests were performed using MTS 858 Mini Bionix.The parameters included load range 0-2000 N,resolution 0.01 N,cross beam replacement resolution 0.001 mm,span 50 mm and loading speed (cross beam replacement speed) 2 mm/min.MAIN OUTCOME MEASURES:Water content,maximal load and elasticity load.RESULTS:The water content of control group was 7%-9%,and following freeze-drying for 8 hours,the water content was 5.5%-6%,which met the standard of freeze-drying bone;Compared with control group,the maximal load and elasticity load reduced respectively 0.004% and 0.000 8% (P＞0.05).Following freeze-drying for 12 and 24 hours,the water content was 3.5%-4% and 1%-1.5%;the maximal load reduced 21% and 37% and the elasticity load reduced 22.5% and 39% compared with control group (P＜0.05).CONCLUSION:Freeze-drying for 8 hours is the best time of dehydration.The mechanical load and elastic modulus reduce with increasing freeze-drying time.

BACKGROUND:Chitosan and gelatin have good biocompatibility and biodegradable properties.More and more attentions have been given to the application of the composite membrane of chitosan/hydroxyapatite(HA)and gelatin/HA as the tissue scaffolds.OBJECTIVE:To prepare a biocompatible composite membrane of chitosan/HA/gelatin having nanometer multilayer HA,and to investigate whether such a membrane might be a candidate of the tissue scaffolds for the bond repair and regeneration,DESIGN:Controlled observation.SETTING:College of Chemistry and Environmental Engineering,Jianghan UniversityMATERIALS:The experiments were performed at the Laboratory of Fine Chemistry,College of Chemistry and Environmental Engineering,Jianghan University from February to August 2007.Chitosan (Yuhnan Ocean Biochemistry Co.,Ltd,Zhengjiang,China,Mw 13.44×104,93% degree of deacetylation),and gelation(provided by Shanghai Chemical Reagent Co.,Shanghai,China)were used in the present study.METHODS:The mixture chitosan/CaCl2 solution was casted on a glass plate to give the membrane of chitosan/CaCl2.Then,the membrane was soaked in KH2PO4 solution,0.1 mol/L NaOH solution,and 3 wt% gelatin aqueous solution,respectively.The resulted membrane was washed and dried to obtain the chtiosan/HA/gelatin composite membrane.The morphological observation of the composite membrane and HA crystal were carded on a scanning electron microscope.The mechanical properties of the composite membrane were measured using the universal testing machine.The tensile strength(σb)and the elongation at break (ε)were calculated.The thermal stability of composite membrane was determined using a WCT-2C thermobalance.MAIN OUTCOME MEASURES:The morphologies,the mechanical properties,and the thermal stability of the composite membrane and HA crystal were observed.RESULTS:The multilayer HA crystal with 400 nm thickness in the composite membrane was observed.The tensile strength(σb)and the elongation at break(ε)of the composite membrane were 3.83-10.25 MPa and 3.97%-10.14%,respectively.The decomposition temperature of HA-treated membrane was 310℃,which was higher than that of chitosan/gelatin membrane(305℃).CONCLUSION:The composite chitosan/HA/gelatin membrane was prepared by using chitosan/CaCl2,KH2PO4 and gelatin solutions.Such a biocompatible composite membrane with multilayer HA might be a promising tissue scaffold.

Hilar cholangiocarcinoma is a rare tumor with a poor prognosis.Due to advances in preoperative imaging and enhanced comprehension of tumor biological behavior,surgical management of hilar cholangiocarcinoma has evolved since its original description.Currently,it has been accepted that complete surgical resection provides the only possibility for cure or long-term survival,however,the surgical management of hilar cholangiocarcinoma is extremely challenging because of its anatomical location and vascular proximity.In order to achieve complete resection, several surgical approaches have been investigated and evaluated regarding major hepatic resection,lymph node dissection,vascular resection,extended resection and liver transplantation,however,there are still many disputations. Furthermore,many surgical technical difficulties exist in biliary reconstruction after resection owing to anatomical problems.Focusing on the disputes and problems mentioned above,we herein review and discuss surgical strategies in managing hilar cholangiocarcinoma.

Objective To explore the application of association rules with Constraints in medical data analysis.Methods Constraints were applied in mining association rules of medical data by analyzing the characteristics of the data.An effective algorithm for mining association rules with constraints from medical data called CAMD was developed.The algorithm was applied to the analysis ofcoronary heart disease dataset.Results Assigning minimum support and minimum confidence as 0.20 and 0.60,respectively,with data from 303 cases of coronary heart dieses analyzed,8 association rules were tained.Crrelations between age,sex,electrocardiograph results,pathogeny and diagnosis of coronary heart disease were discovered.Conclusion Results from our experiments show that CAMD scans the database fewer times and has no need of pruning candidate itemsets.Thus,it greatly decrease the amount of useless rules produced and rapidly discover interesting association rules of medical data.

Objective To evaluate the efficacy and safety of sufentanil used for patient-controlled subcutaneous analgesia (PCSA) with different models after craniotomy.Methods Sixty ASA Ⅰ～Ⅱ patients undergoing craniotomy were randomly divided into two groups with or without background infusion. Sufentanil 0.12 mg was used via patient-controlled analgesia (PCA) and no loading dose was administered. The PCA device was programmed background infusion of 1 ml/h, bolus dose of 0.5 ml in group of using continuance plus PCA model (group CP) and bolus dose of 0.75 ml without background infusion in group P. Hour limit of 3 ml/h, lockout time of 15 minutes were set in two groups. Postoperative pain was assessed at rest and when moving, using Visual Analogue Scale (VAS) at 2 h, 20 h, 24 h, 44 h and 48 h after operation. Side-effects were also recorded systematically during the first 48 h after surgery.Results No significant differences were observed in patients' physical status, fentanyl consumption during operation and anaesthetic time. There were no significant differences in VAS scores between the two groups within 48 h after operation, but the incidence of complaining postoperative pain was significantly more in group P than that in group CP at 20 h and 24 h after surgery (P<0.05). The cumulative analgesic consumption of sufentanil in group CP and group P were 98.73±5.96 μg and 57.25±9.73 μg, respectively (P<0.05). Compared with group P, the mean arterial pressure in 20 h and 24 h were significantly lower in group CP (P<0.05). The sedation degree and the incidence of nausea, vomiting in two groups had no significant differences. No restrain of respiration occurred in two groups. The patients' satisfactory rate with PCA in group CP and group P were 90% and 80%, respectively.Conclusion PCSA with sufentanil and continuance plus PCA model is an effective and safe analgesic method after craniotomy.

Objective To study the value of bone marrow MR imaging in mornitoring chronic myeloid leukemia(CML).Methods 12 cases of CML underwent twice MR examination of pelvis and femur respectively at different time.MRI appearances were compared with the results of morphology and blood routine at the same time.The relation between MR findings and course was analysed.Results MR appearances of bone marrow were changed with the progression of disease.The condition of patients was improved in 2 cases and worse in 4 cases,the signal intensity of bone marrrow were increased and decreased respectively.The signal intensity of bone marrow showed no change in 6 patients whose condition kept stable.Conclusion The characteristics of MRI can reflect the progression of CML,it is of important value in mornitoring this disease.

Objective To investigate the clinical application of free submental flap for defects reconstruction after oral cancer ablation.Methods Eleven cases of free submental flaps for defects reconstruction after oral cancer ablation from April,2013 to May,2014 were reviewed.The primary disease,defect type,flap side,flap size and flap survival rate were recorded.The follow-up data of tumor recurrence,lymph node metastasis,as well as postoperative facial appearance and function of marginal mandibular branch of facial nerve were collected.Results Primary disease of all 11 cases was oral squamous cell carcinoma.No flap failure was reported and the overall flap survived.The follow-up period was 6-18 months with the average of 9 months.There was no tumor recurrence and metastasis of lymph node.Postoperative facial appearance was satisfactory and there was no nerve injury of marginal mandibular branch which showed normal and symmetrical expression motion.Conclusion Free submental flap owns many ad vantages including constant anatomy,long vascular pedicle,wide range of indications and low donor-site morbidity.Contralater submental flap may avoid potential lymph node metastasis.Free submentai flaps is an ideal choice for reconstruction of oral and maxillofacial defects after cancer ablation.

Objective:To generate Epstein-Barr virus(EBV) Latent Membrane Protein 2A(LMP2A) recombinant adenovirus,and provide for further investigation on the therapy vaccine against EBV associated malignancies.Methods:Full length cDNA of encoding LMP2A of EBV had been amplified by reverse transcription-PCR and cloned into pGEM-T vector.The encoding cDNA of LMP2A was inserted into E1,E3-substituted adenovirus vector pAX1CW,then the LMP2A recombinant adenovirus vector was contransfected into 293 cells togetherwith EcoT221 digested Ad5-TPC.The LMP2A recombinant adenovirus was generated by homologous recombination,and primarily identificated by ClaI enzyme digestion.The expression of LMP2A on CV1 cells infected with recombinant adenovirus analyzed by fluorescence-activated cell sorting(FACS) and confocal microscope.Results:The replication-deficient LMP2A recombinant adenovirus was generated efficiently with the titers of 2.3?10 8 pfu/ml.The LMP2A could be seen on CV1 cells membrane with confocal microscope 48 h post infected with recombinant adenovirus and the percentage of CV1 cells expressing LMP2A was 94.4% by means of FACS analysis.Conclusion:These suggested that LMP2A could be expressed efficiently by recombinant adenovirus mediated transfer,and it was the foundation of further researching in its function and developing the suitable genetic engineering vaccine against EBV associated malignancies.

BACKGROUND: The application of three-dimensional (3D) precision printing in orthopedic rehabilitation medicine is attracting more and more attention from clinicians, engineers and researchers. OBJECTIVE: To review the development of 3D printing in orthopedic rehabilitation. METHODS: Relevant documents published from 2011 to 2019 were retrieved from CNKI database, Wanfang database, PubMed database and Elsevier database by computer. The search terms were “3D Precision Printing, Orthopedic rehabilitation medicine, Artificial Intelligence” in English and Chinese. RESULTS AND CONCLUSION: At present, 3D precision printing is the key technology in the application of orthopedic rehabilitation medicine, including medical image processing and 3D modeling, surgical simulation planning system, surgical guide board design, implant design and 3D precision printing equipment. Among them, 3D reconstruction technologies such as multiplanar reconstructions, volume rendering technique, maximum intensity projection, minimum intensity projection and surface shaded display are used to read medical digital data and realize visual medical image processing and 3D modeling, which can improve doctor-patient communication efficiency. The thinking process and intelligent behavior of doctors in rehabilitation surgery can be simulated by computer, and a cloud service center with function similar to the brain intelligence of doctors is created to assist doctors in the planning of rehabilitation surgery. With the aid of personalized rehabilitation surgery guide board design software, the bone graft osteotomy guide board can be used to plan the osteotomy line and osteotomy range for the doctor, which can shorten the operation time and improve the operation safety. Using polymer materials, metal materials, ceramic materials and other materials as 3D printing materials, there are still problems such as poor mechanical adaptation and physiological adaptation. The automation degree of common biological 3D design software is relatively low, which is prone to problems such as unsatisfactory matching between the performance of orthopedic medical devices and the defect site, and single internal pore structure of implants. However, the application of 3D precision printing technology in the immersion rehabilitation medicine teaching system is beneficial to the cultivation of rehabilitation medicine talents combining with interdisciplinary medical workers.

Objective To evaluate the accuracy of ultrasonographic measurement of the transverse diameter of the cricoid cartilage in selecting the cuffed endotracheal tube (ETT) size for pediatric patients.Methods A total of 120 pediatric patients of both sexes,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,aged 1 month-6 yr,with body mass index of 10.9-31.2 kg/m2,undergoing endotracheal intubation and general anesthesia,were divided into group A and group B,with 60 pediatric patients in each group.The pediatric patients were intubated with a cuffed ETT in two groups.The ETT size was selected based on the transverse diameter of the cricoid cartilage measured by ultrasonography in group A.The ETT size was selected according to the age-based formula in group B.A tracheal leak was detected after intubation to determine whether or not the ETT size selected was appropriate.ETTs were replaced when the actually selected ones were not appropriate,and the number of replacement was recorded.The development of intubation-related complications was also recorded.Results The accurate rate of cuffed ETT size selected at the first time was 95％ in group A,and it was significantly higher than that in group B (60％) (P＜ 0.05).There was no significant difference in the incidence of intubation-related complications between the two groups (P＞0.05).Conclusion Uhrasonographic measurement of the transverse diameter of the cricoid cartilage produces higher accuracy in selecting the cuffed ETT size for pediatric patients and is worthy of clinical application.