ObjectiveTo evaluate the effect of nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for living model of canine tibial plateau collapse fracture by biomechanical testing. MethodsSixteen healthy 12-month-old Beagle dogs were randomly divided into 4 group, 4 dogs in each group. The dogs were used to establish the tibial plateau collapse fracture model in groups A, B, and C. Then, the nickel-titanium three-dimensional memory alloy mesh combined with autologous bone (the fibula cortical bone particles), the artificial bone (nano-hydroxyapatite), and autologous fibula cortical bone particles were implanted to repair the bone defects within 4 hours after modeling in groups A, B, and C, respectively; and the plate and screws were fixed outside the bone defects. The dogs were not treated in group D, as normal control. At 5 months after operation, all animals were sacrificed and the tibial specimens were harvested and observed visually. The destructive axial compression experiments were carried out by the biomechanical testing machine. The displacement and the maximum failure load were recorded and the axial stiffness was calculated. ResultsAll animals stayed alive after operation, and all incisions healed. After 1-3 days of operation, the animals could stand and move, and no obvious limb deformity was found. The articular surfaces of the tibial plateau specimens were completely smooth at 5 months after operation. No obvious articular surface collapse was observed. The displacement and maximum failure load of specimens in groups A and D were significantly higher than those in groups B and C (P<0.05). But no significant difference was found between groups A and D and between groups B and C (P>0.05). ConclusionThe nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for subarticular bone defect of tibial plateau in dogs has good biomechanical properties at 5 months after operation, and has better axial stiffness when compared with the artificial bone and autologous bone graft.
Objective
To construct a new composite artificial trachea and to investigate the feasibility of trachea repair and reconstruction with the new composite artificial trachea transplantation in dogs.
Methods
The basic skeleton of the new composite artificial trachea was polytetrafluoroethylene vascular prosthesis linked with titanium rings at both ends. Dualmesh was sutured on titanium rings. Sixteen dogs, weighing (14.9 ± 2.0) kg, female or male, were selected. The 5 cm cervical trachea was resected to prepare the cervical trachea defect model. The trachea repair and reconstruction was performed with the new composite artificial trachea. Then fiberoptic bronchoscope examination, CT scan and three-dimensinal reconstruction were conducted at immediate, 1 month, and 6 months after operation. Gross observation and histological examination were conducted at 14 months to evaluate the repair and reconstruction efficacy.
Results
No dog died during operation of trachea reconstruction. One dog died of dyspnea at 37, 41, 55, 66, 140, and 274 days respectively because of anastomotic dehiscence and artificial trachea displacement; the other 10 dogs survived until 14 months. The fiberoptic bronchoscope examination, CT scan and three-dimensinal reconstruction showed that artificial tracheas were all in good location without twisting at immediate after operation; mild stenosis occurred and anastomoses had slight granulation in 6 dogs at 1 month; severe stenosis developed and anastomosis had more granulation in 1 dog and the other dogs were well alive without anastomotic stenosis at 6 months. At 14 months, gross observation revealed that outer surface of the artificial trachea were encapsulated by fibrous connective tissue in all of 10 dogs. Histological examination showed inflammatory infiltration and hyperplasia of fibrous tissue and no epithelium growth on the inner wall of the artificial trachea.
Conclusion
The new composite artificial trachea can be used to repair and reconstruct defect of the trachea for a short-term. Anastomotic infection and dehiscence are major complications and problems affecting long survival.
Objective To investigate an improved large vascular reconstruction method in the canine liver transplantation and see whether it can shorten the anheptic time and thus reduce the harmful effects during the anhepatic phase. Methods Thirty-two mongrel dogs were enrolled and divided into two groups randomly:the donor group (n=16) and the acceptorgroup(n=16). The dogs in the acceptor group were divided into two groups, according to the different reconstruction methods: Group A using the magnetic rings for a large vein reconstruction in the canine liver transplantation (n=10), and Group B using a handsewing large vein reconstruction in the canine liver transplantation (n=6). The operation time, hemodymics change, anastomosis site, and survival were observed. Results The operation time was as follows: In Group A, the total operation time, the inferior vena cava anastomosistime, and the anheptic phase time were significantly shorter than those in Group B (3.24±0.49 h vs 4.12±0.51 h，5.89±2.27 min vs 28.33±6.04 min，3.89±0.73 min vs 12.16±3.72 min),with a significant difference between the two groups (Plt;0.01). The haemodymics changes were as follows: In Group A, MAP dropped during the anhepatic phase, but it soon recovered after reperfusion，and there was only 730.56±150.56 ml of fluid including the donor blood that needed to be transfused, with no pressor agent required. In Group B, blood pressure dropped during the anhepatic phase，but it slowly recovered，and there was 2241.67±390.78 ml of fluid. In Group A, all the stomas had no errhysis, twistor thrombus. The twisted stomas could be corrected by the revolving of the magnetic rings. The endangium at the site of anastomosis was smooth. In Group B, most of the stomas had errthysis. In Group A, 3 dogs survived for more than 7 days, 6dogs survived for 3-6 days, and 1 dog survived for only 12 hours. In Group B, 2 dogs survived for 3-6 days, 3 dogs survived for 1-2 days, and 1 dog survivedfor only 12 hours. Conclusion Using the magnetic rings for a large vascular reconstruction in the canine liver transplantation is an improvedmethod, which can simplify the anastomosis procedures and significantly shortenthe anheptic phase time. However, the magnetic rings have to be placed in the abdomen, so this method remains to be further improved.
Objective Native extracellular matrix (ECM) is comprised of a complex network of structural and regulatory proteins that are arrayed into a tissue-specific, biomechanically optimal, fibrous matrix. The multifunctional nature of the native ECM will need to be considered in the design and fabrication of tissue engineering scaffolds. To investigate the extraction techniques of naturally derived nerve ECM and the feasibil ity of nerve tissue engineering scaffold. Methods Ten fresh canine sciatic nerves were harvested; nerve ECM material was prepared by hypotonic freeze-thawing, mechanicalgrinding, and differential centrifugation. The ECM was observed by scanning electron microscope. Immunofluorescencestaining was performed to detect specific ECM proteins including collagen type I, laminin, and fibronectin. Total collagen and glycosaminoglycan (GAG) contents were assessed using biochemical assays. The degree of decellularization was evaluated with staining for nuclei using Hoechst33258. The dorsal root gangl ion and Schwann cells of rats were respectively seeded onto nerve tissue-specific ECM films. The biocompatibil ity was observed by specific antibodies for cell markers. Results Scanning electron microscope analysis revealed that nerve-derived ECM consisted of a nanofibrous structure, which diameter was 30-130 nm. Immunofluorescence staining confirmed that the nerve-derived ECM was made up of collagen type I, laminin, and fibronectin. The histological staining showed that the staining results of sirius red, Safranin O, and toluidine blue were positive. Hoechst33258 staining showed no DNA within the decellularized ECM. Those ECM films had good biocompatibil ity for dorsal root gangl ion and Schwann cells. The cotents of total collagen and GAG in the nerve-derived ECM were (114.88 ± 13.33) μg/ mg and (17.52 ± 2.34) μg/mg, showing significant difference in the content of total collagen (P lt; 0.01) and no significant difference in the content of GAG (P gt; 0.05) when compared with the contents of normal nerve tissue [(54.07 ± 5.06) μg/mg and (25.25 ± 1.56) μg/mg)]. The results of immunofluorescence staining were positive for neurofilament 200 after 7 days and for S100 after 2 days. Conclusion Nerve-derived ECM is rich in collagen type I, laminin, and fibronectin and has good biocompatibil ity, so it can be used as a nerve tissue engineering scaffold.
Objective To investigate the effect of imbedding chemotherapy of sustained release of 5-fluorouracil on the healing of colonic stoma in dog. Methods Twenty-eight adult hybrid dogs were randomly divided into chemotherapy group （n=22) and control group (n=6). The canine sigmoid colon were firstly detached and then anastomosed via median abdominal incision, 200 mg sustained release of 5-fluorouracil was imbedded in the mesentery 1.0-1.5 cm away from colonic stoma in chemotherapy group, whereas the control substance was injected into the dogs in control group. Tissue samples were collected from mesentery and stomas on 3, 5, 7, 10 and 15 days after operation, respectively, in order to observe the healing of stoma. The drug concentrations in the stoma and in the tissues that were 0, 1, 3, 5, 7, 10 and 15 cm away from the imbedding point were also measured by high performance liquid chromatographymethod at different phases. Results The tissues from colonic stoma only showed inflammatory reaction at early stage, with no necrosis and cellular degeneration. It was observed that the stoma healed basically on the tenth day after operation. The drug concentrations in the tissues gradually decreased at the range of 0-15 cm over time, but all of which were higher than the anti-tumor effective concentration （0.10 μg/g）. Conclusion The imbedding chemotherapy of sustained release of 5-fluorouracil in mesentery has little effect on the healing of stoma, and it could remain an effective anti-tumor concentration in a period of time.
ObjectiveTo investigate the situation of internal antibody positive rate of Chinese who exposed to rabies virus and received full procedure of rabies vaccination, and to provide the basis for the adjustment of rabies vaccination procedure and policy.
MethodsWe electronically searched databases including WanFang Data, VIP, CNKI, PubMed and EMbase from inception to May 2015 to collect studies about Chinese exposed to rabies virus and received full procedure rabies vaccination. Two reviewers independently screened literature, extracted data, and assessed the methodological quality of included studies. Then, meta-analysis was performed using R software (R3.2.1).
ResultsA total of 33 studies were included. The combined antibody positive rate was 93.99% with 95%CI 92.02% to 95.70%. Antibody positive rate among male was 93.73% with 95%CI 91.65% to 95.54%, while among female was 94.33% with 95%CI 92.35% to 96.04%, and there was no significant difference between male and female (P>0.05). The antibody positive rate of hamster kidney cell rabies vaccine was 89.94% with 95%CI 86.09% to 95%, while the antibody positive rate of vero cell rabies vaccine was 96.65% with 95%CI 94.99% to 94.99%, and there was significant difference between both groups (P<0.05). There was no statistical difference in antibody positive rates among different years of rabies vaccine (P>0.05). However, the antibody positive rate of rabies vaccine had a tendency to reduce with the increasing age
ConclusionAntibody positive rate of vero cell rabies vaccine is higher than that of hamster kidney cell rabies vaccine. Older people have lower antibody positive rate after receiving rabies vaccination. We suggest using vero cell rabies vaccine when giving rabies vaccination; elderly people should receive booster vaccination after basic vaccination.
Objective To observe whether additional penehycl idine hydrochloride (PHC) in mechanical ventilation produces therapeutic effect on oleic acid (OA) induced acute lung injury (ALI) in canine. Methods Seventeen male canines (weighing 12-17 kg) were divided into control group (n=5), OA group (n=6) and PHC group (n=6). ALI model was developed by central venous injection of OA in canines of OA and PHC groups. ALI model was kept steady in air, all groups received mechanical ventilation 90 minutes later. Three groups received normal sal ine 0.25 mg/kg without injection of OA(control group), normal sal ine 0.25 mg/kg after injection of OA (OA group) and PHC 0.25 mg/kg after injection of OA (PHCgroup) respectively at 0 h (90 minutes after onset time of ALI/ARDS). The heart rate (HR), mean arteial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), artery blood gas analysis, cardiac output (CO), extravascular lung water index (EVLWI), FiO2 and VT were observed respectively at basel ine, onset time of ALI/ARDS and 0 h, then again at 1 hour intervals for 6 hours. Besides the above, airway peak pressure (Ppeak), airway plat pressure (Pplat), mean airway pressure (Pmean) and positve end-expriatory pressure (Peep) were also observed each hour during 1-6 hours. Oxygenation index (OI), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), alveolar-arterial differences for O2 (AaDO2) and dynamic lung compl iance (DLC) were calculated and pulmonary tissue was collected for histopathologic investigation and dry wet weight ratio (WDR) test. Results The functional parameters of PHC group were improved when compared those of OA group, but there was no siginficant difference; WDR of independent region of three groups were 80.42% ± 3.48%, 82.67% ± 4.01% and 82.26% ± 1.43% respectively; WDR of dependent region of three groups were 80.51% ± 3.60%, 83.71% ± 1.98% and 82.57% ± 1.08% respectively. WDR of PHC group were obviously improved when compared with those of OA group, but there was no significant difference. Independent and dependent regions of PHC group were significantly improved when compared those of OA group in histopathologic scores, alveolar edema, inflammatory infiltration and over-distension (P lt; 0.01). Conclusion Additional PHC in mechanical ventilation produces obvious therapeutic effect on OA induced acute lung injury in canine.
