ObjectiveTo compare the fixation strength of optimum placed pedicle screw (OS) with re-directionally correctly placed pedicle screw (RS) following a violation of lateral pedicle. MethodsThirty fresh lumbar vertebrae (L1-5) were obtained from 6 pigs weighing 95-105 kg, male or female. Each vertebra was instrumented with a monoaxial pedicle screw into each pedicle using two different techniques. On one side, a perfect screw path was created using direct visualization and fluoroscopy. A pedicle screw of 5 mm in diameter and 35 mm in length was placed with a digital torque driver (OS). On the other side, a lateral pedicle wall violation was created at the pedicle-vertebral body junction with a guide wire, a cannulated tap, and a pedicle probe. This path was then redirected into a correct position, developed, and instrumented with a 5-mm-diameter by 35-mm-long pedicle screw (RS). For each pedicle screw, the maximal torque, seating torque, screw loosening force, and post-loosening axial pullout were measured. Screw loosening and axial pullout were assessed using an MTS machine. ResultsMaximal insertion torque was (111.4±8.2) N·cm and (78.9±6.4) N·cm for OS and RS respectively, showing significant difference (Z=3.038, P=0.002). The seating torque was (86.3±7.7) N·cm and (59.7±5.3) N·cm for OS and RS respectively, showing significant difference (Z=2.802, P=0.005). The screw loosening force was (76.3±6.2) N and (53.0±5.8) N for OS and RS respectively, showing significant difference (Z=2.861, P=0.004). The post-loosening axial pullout force was (343.0±12.6) N and (287.0±10.5) N for OS and RS respectively, showing significant difference (Z=2.964, P=0.003). ConclusionCompared with OS, RS placement after a lateral wall violation shows significantly decreased maximal insertion torque, seating torque, screw loosening force, and post-loosening axial pullout. On this occasion, RS augmentation is a probable option for remediation.
ObjectiveTo explore the application of extracorporeal venovenous bypass in orthotopic liver transplantation in pigs and to compare hemodynamic changes during operation of two different bypass ways. MethodsTwentyfive porcine orthotopic liver transplantations were performed and extracorporeal venovenous bypass was established during anhepatic phase through a catheter in portal vein (group A,n=16) or in splenic vein (group B,n=9).Hemodynamic changes were monitored continuously.ResultsFourteen recipients survived two days after operation (14/16) in group A while all survived in group B (9/9).Transient hemodynamic disturbance (MAP and CVP decreased,and HR increased) was monitored at both the beginning and the end of anhepatic stage in group A,while these parameters kept stable in group B (P＜0.05).ConclusionApplying venovenous bypass may stabilize recipients’ hemodynamics in porcines orthotopic liver transplantation,and splenic vein draining way has more advantages than portal vein.
ObjectiveTo investigate the aim antigen coursing the hyperacute rejection of xenotransplantation. MethodsDocuments about hyperacute rejection in xenotransplantation were reviewed and summarized in detail. ResultsPig is thought to be one of the ideal donors of xenotransplantation, but the major obstacle is hyperacute rejection mediated by complement that is activated though human serum. αGal is recognized as the major antigen and its expression is controlled by α1,3 galactosyltransferase. Immunoabsorption of preexsisted antibody, enzymatic digestion of αGal, knockout αGT gene and transgenic technology have been used to solve this problem. Even so, there remain other antigens which can combine with natural antibodies in human serum, such as, 40×103 molecule in erythrocyte, 210×103, 105×103 and 50×103 antigen in pig embryo brain cell, etc. Conclusion αGal is the major antigen which course the hyperacute rejection. Besides αGal, many nonalphagal need further investigation.
Objective To investigate the mechanism of hyperacute rejection (HAR) in pig to rhesus monkey vein xenograft. Methods Porcine femoral vein was transplanted into rhesus monkey. Deposits of IgM, IgG, C3 and C4 on the grafts were observed by immunoflurescence. Results Great deal of IgM, C3 and C4 were seen along the endothelium of donor vein, but IgG was not seen. ConclusionIn pig to monkey xenograft model, HAR is intiated by the binding of xenoreactive IgM to donor xenoantigens and followed by the activation of complement via the classical pathway.
Piggyback allogeneic orthotopic liver transplantation was performed successfully in a patient with primary biliary cirrhosis on July 26,1996. Topographic study of hepatic veins and short hepatic veins were made in 17 adult cadavers. The majority of short hepatic veins were found in the middle and lower portion of inferior vena cava (IVC) behind liver, but two of 17 cases had a big accessory middle hepatic vein and the right hepatic vein (1 case) divided four branchs into IVC in the area. The lengths of the main trunk of left, middle and right hepatic vein were 22.8±8.80 mm, 50.98±23.94 mm and 22.80±9.50 mm and the diameters were 10.74±2.86 mm, 9.50±3.75 mm and 15.60±4.05 mm respectively. The right hepatic vein in all cases, except one drained into IVC as one vessel. The middle and left hepatic vein drained into IVC in different forms: ①joining as one vessel longer than 1cm before entering IVC (23.5%);②joining right before entering IVC (70.6%); ③draining into IVC separately (5.9%). The distance between right and middle hepatic vein was 7-23 mm. Topography of hepatic veinous flow related with the technique of piggyback operation and removing of diseased liver is discussed.
Objective To investigate the effect of intra-abdominal hypertension(IAH) on respiratory function in pigs.Methods Twelve pigs were randomly divided into two groups (n=6 in each group),ie.IAH20 group(intra-abdominal pressure=20 mm Hg) and IAH30 group(intra-abdominal pressure=30 mm Hg).Pig model of IAH was established by intraperitoneally injection of carbon dioxide.The changes in respiratory function parameters including pulmonary dynamic compliance（Cdyn），peak inspiratory pressure(PIP) ,SpO2 and PaCO2 were recorded at different time points.Results Cdyn was significantly decreased at different time points compared with baseline in group IAH30 and group IAH20.PIP significantly increased at different time points compared with baseline in both IAH groups，but group IAH30 was more severe than group IAH20. No significant changes of SpO2 and PaCO2 were found in two IAH groups.Conclusion IAH can impair respiratory function by decreasing lung compliance and increasing inspiratory pressure.
Objective To explore the effectivness of arthroscopic synovectomy in the treatment of pigmented villonodular synovitis (PVNS) of the knee. Methods A retrospective analysis was conducted on 13 patients with PVNS of the knee treated with arthroscopic synovectomy between June 2008 and December 2011, including 8 left knees and 5 right knees. There were 9 males and 4 females, aged 25-45 years (mean, 33 years). Of 13 patients, 5 had a history of trauma, and 8 had no history of trauma. The disease duration ranged from 4 months to 80 months (mean, 44 months). The preoperative Lysholm score was 45.3 ± 4.2, and International Knee Documentation Committee (IKDC) 2000 score was 46.8 ± 4.9. All patients underwent arthroscopic synovectomy and postoperative radiotherapy. Results The pathological examination proved PVNS in all cases. All incisions obtained healing by first intention after operation. There was no neurovascular injury or knee infection. The average follow-up period was 21.8 months (range, 12-30 months). The Lysholm score was 90.2 ± 7.4, and IKDC2000 score was 87.8 ± 3.8 at last follow-up, showing significant differences when compared with preoperative scores (t=22.64, P=0.00; t=24.32, P=0.00). No recurrence was observed during follow-up. Conclusion Arthroscopic synovectomy can be effective in the treatment of PVNS of the knee, and it has the merits of minimal invasion, rapid function recovery of the knee joint, and satisfactory results. So it is a safe, promising, and minimal invasive procedure in treatment of PVNS.
Objective To investigate the effects of different temperatures on the system of in vitro physiological environment fostering limbs. Methods Twenty-four limbs were harvested from 6 adult Bama mini pigs and were randomly divided into 4 groups (n=6) according to different temperatures: limbs were placed in in vitro physiological environment foster-ing limbs at 26℃ (group A), 4℃ (group B), 10℃ (group C), and 18℃(group D). After 12 hours of perfusion, the morphology observation was done for the structure and ultrastructure changes of the skeletal muscle by light microscope and transmission electron microscope. The mRNA levels of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were detected by real-time fluorescent quantitative PCR (RT-qPCR). Results Histological results showed that the skeletal muscle exhibited mild edema, integrity of the sarcolemma, and occasional perivascular inflammatory cell infiltration in groups B, C, and D, meanwhile, the cells of group C had normal morphology; however, muscle fibers degenerated, muscle cells were seriously damaged, a great number of inflammatory cells infiltrated in the fractured muscle fibers in group A. Transmission electron microscope results showed as follows: the muscle fibers arranged in disorder, and many focal solubility necrosis occurred in group A; the muscle fibers arranged in order relatively and sarcolemma was still intact, with mild swelling and flocculent degenerative mitochondria in group B; a large number of muscle fibers arranged in order and regularity with clear sarcomere in group C; and the muscle fibers arranged in disorder and irregularity and partly dissolved in group D. RT-qPCR results showed that the expressions of inflammatory factor TNF-α and IL-1β mRNA in group A were significantly higher than those in groups B, C, and D (P lt; 0.05); the expressions were significantly lower in groups B and C than in group D, and in group C than in group B (P lt; 0.05). Conclusion In the system of in vitro physiological environment fostering limbs, temperature plays an important role in the preservation of amputated limbs. It is suggested that 10℃ can significantly attenuate the reperfusion-induced skeletal muscle cell injuries in this system.
Objective To fabricate a novel composite scaffold with acellular demineralized bone matrix/acellular nucleus pulposus matrix and to verify the feasibility of using it as a scaffold for intervertebral disc tissue engineering through detecting physical and chemical properties. Methods Pig proximal femoral cancellous bone rings (10 mm in external diameter, 5 mm in internal diameter, and 3 mm in thickness) were fabricated, and were dealed with degreasing, decalcification, and decellularization to prepare the annulus fibrosus phase of scaffold. Nucleus pulposus was taken from pig tails, decellularized with Triton X-100 and deoxycholic acid, crushed and centrifugalized to prepare nucleus pulposus extracellular mtrtix which was injected into the center of annulus fibrosus phase. Then the composite scaffold was freeze-dryed, cross-linked with ultraviolet radiation/carbodiimide and disinfected for use. The scaffold was investigated by general observation, HE staining, and scanning electron microscopy, as well as porosity measurement, water absorption rate, and compressive elastic modulus. Adipose-derived stem cells (ADSCs) were cultured with different concentrations of scaffold extract (25%, 50%, and 100%) to assess cytotoxicity of the scaffold. The cell viability of ADSCs seeded on the scaffold was detected by Live/Dead staining. Results The scaffold was white by general observation. The HE staining revealed that there was no cell fragments on the scaffold, and the dye homogeneously distributed. The scanning electron microscopy showed that the pore of the annulus fibrosus phase interconnected and the pore size was uniform; acellular nucleus pulposus matrix microfilament interconnected forming a uniform network structure, and the junction of the scaffold was closely connected. The novel porous scaffold had a good pore interconnectivity with (343.00 ± 88.25) µm pore diameter of the annulus fibrosus phase, 82.98% ± 7.02% porosity and 621.53% ± 53.31% water absorption rate. The biomechanical test showed that the compressive modulus of elasticity was (89.07 ± 8.73) kPa. The MTT test indicated that scaffold extract had no influence on cell proliferation. Live/Dead staining showed that ADSCs had a good proliferation on the scaffold and there was no dead cell. Conclusion Novel composite scaffold made of acellular demineralized bone matrix/acellular nucleus pulposus matrix has good pore diameter and porosity, biomechanical properties close to natural intervertebral disc, non-toxicity, and good biocompatibility, so it is a suitable scaffold for intervertebral disc tissue engineering.
Objective To investigate the effects of sustained-release basic fibroblast growth factor (bFGF) on healing of bile duct defect. Methods A model of bile duct wall defect (2 cm in length and 1/3-2/3 of the bile duct circumference in width) was made in 24 pigs (male or female, weighing 15-30 kg), and then defect was repaired with sustained-release bFGF collagen membrane (2.0 cm × 1.0 cm × 0.5 cm in size) in the experimental group (n=12) or with collagen membrane (2.0 cm × 1.0 cm × 0.5 cm in size) alone in the blank control group (n=12). Another 4 healthy pigs were used to obtain normal bile duct as normal control group. The survival condition of pigs was observed after operation; at 1, 2, and 3 months after operation, the blood sampling was collected to test the changes of liver function, and the bile duct specimens were harvested to count the microvessel density (MVD) and submucosal gland by HE staining and immunohistochemistry staining; and at 3 months after operation, cholangiography examination was done. Results All the animals survived to completion of the experiment. Intra-abdominal adhesion was serious in the experimental and blank control groups at 1 week after operation, but the adhesion was markedly improved in the experimental group when compared with the blank control group with time passing. The liver function test showed that alkaline phosphatase in the experimental group was significantly lower than that in the blank control group at 2 and 3 months (P lt; 0.05), but no significant difference in aspartate aminortransferase, total bilirubin, and albumin was found among 3 groups (P gt; 0.05). The histology and immunohistochemistry staining observations showed that the regeneration rates of submucosal glands and epithelium in the experimental group were faster than those in the blank control group; defect was covered with the epithelium at 2 months, and the structure was similar to that of normal control group at 3 months; and the edema and inflammation infiltration were reduced when compared with the blank control group. The counts of MVD and submucosal gland were significantly higher than those in blank control group and normal control group at 1 month after operation (P lt; 0.05), and then decreased and remained at normal levels at 2 months after operation. There was a positive correlation between submucosal gland counting and MVD counting in 3 groups after operation (P lt; 0.01). The cholangiography examination showed no biliary dilatation or cholelithiasis after 3 months in experimental group and blank control group. Conclusion Sustained-release bFGF can promote healing of bile duct defect by accelerating the vascularization, gland regeneration, and epithelialization.