The freeze-drying is a technology that preserves biological samples in a dry state, which is beneficial for storage, transportation, and cost saving. In this study, the bovine pericardium was treated with a freeze-drying protectant composed of polyethylene glycol (PEG) and trehalose (Tre), and then freeze-dried. The results demonstrated that the mechanical properties of the pericardium treated with PEG + 10% w/v Tre were superior to those of the pericardium fixed with glutaraldehyde (GA). The wet state water content of the rehydrated pericardium, determined using the Karl Fischer method, was (74.81 ± 1.44)%, which was comparable to that of the GA-fixed pericardium. The dry state water content was significantly reduced to (8.64 ± 1.52)%, indicating effective dehydration during the freeze-drying process. Differential scanning calorimetry (DSC) testing revealed that the thermal shrinkage temperature of the pericardium was (84.96 ± 0.49) ℃, higher than that of the GA-fixed pericardium (83.14 ± 0.11) ℃, indicating greater thermal stability. Fourier transform infrared spectroscopy (FTIR) results showed no damage to the protein structure during freeze-drying. Hematoxylin and eosin (HE) staining demonstrated that the freeze-drying process reduced pore formation, prevented ice crystal growth, and resulted in a tighter arrangement of tissue fibers. The frozen-dried bovine pericardium was subjected to tests for cell viability and hemolysis rate. The results revealed a cell proliferation rate of (77.87 ± 0.49)%, corresponding to a toxicity grade of 1. Additionally, the hemolysis rate was (0.17 ± 0.02)%, which is below the standard of 5%. These findings indicated that the frozen-dried bovine pericardium exhibited satisfactory performance in terms of cytotoxicity and hemolysis, thus meeting the relevant standards. In summary, the performance of the bovine pericardium treated with PEG + 10% w/v Tre and subjected to freeze-drying could meet the required standards.
Objective
To systematically review the efficacy and safety of polyethylene glycol and sodium phosphate in bowel preparation of capsule endoscopy.
Methods
We searched CNKI, CBM, WanFang Data, PubMed, EMbase, and The Cochrane Library (Issue 6, 2016) up to June 2016, to collect randomized controlled trials (RCTs) about polyethylene glycol and sodium phosphate in bowel preparation of capsule endoscopy. Two reviewers independently screened literatures, extracted data and assessed the risk of bias of included studies, and then meta-analysis was performed by using RevMan 5.0 software.
Results
A total of six RCTs involving 531 patients were included. The results of meta-analysis showed that: compared with the sodium phosphate solution group, the polyethylene glycol solution group had poor intestinal cleansing effect (OR=0.43, 95%CI 0.21 to 0.88,P=0.02), higher incidence of adverse reaction (OR=3.20, 95%CI 1.13 to 9.06,P=0.03); but shorter gastric retention time (OR=–11.61, 95%CI –13.71 to –9.51,P<0.000 01) and residence time in the small intestine (OR=–4.17, 95%CI –7.74 to –0.60,P=0.02).
Conclusion
The efficacy of oral polyethylene glycol is poor in cleaning effect and adverse reaction than sodium phosphate solution, but better in the digestive tract residence time for capsule endoscopy. Due to the limited quality and quantity of included studies, the above conclusion is still needed to be proved by more high-quality studies.
Objective To study the effect of the high molecular weight polyethylene on the periprosthetic tissue in vivo as to give some reference to treatment of loosening hip arthroplasty. Methods Every lower limb of 20 New Zealand white rabbits was implanted a CoCrMo plug in femur by intercondylar notch. 15 mg polyethylene particles, dispersed in 1.5 ml normal saline solution, were injected into one knee joint. The other knee joint was injected 1.5 ml normal saline solution as control. This procedure was repeated 2,4,6,8 and 10 weeks after the implantation. Both of two lower limbs were given a X-ray examination 10 weeks to assess if there were periprosthetic osteolysis and loosening of the plugs. All animals were killed 2 weeks afer the last injection. The distribution of polyethylene in the knee joint capsule was examined to understand if there were loosening of implants or tissue change around implants. Knee joint capsule tissues and periprosthetic tissues were examed by optical microscope. Results Nine cases formed fibrous membrane and four cases formed new bone around prostheses in experiment group. Eleven cases formed new bone and two cases formed fibrous membrane in control group(Plt;0.05)The X-ray results indicated that the plugs were in distal medulla of femur. There was no sign of priprosthetic osteolysis, implants loosening or new bone formation. Optical microscope study indicated that there were a lot of polyethylene particles inside the capsule. The polythlene particles were surrounded by multinucleated foreignbody giant cells and fibrobast. In some cases, there were fibroblasts and fibrous tissue around plug. There were no polyethylene paticles and multinucleated foreignbody giant cells around plug in the marrow. There were alot of polyehtlene particles on the joint surface. The bone surface that contacted multinucleated foreignbody giant cells was coarse. Conclusion Maximing ultra high molecular weight polyethylene can restrain rabbit periprosthetic bone formation
Objective To develop a tissue engineering scaffold by using 4arm branched polyethylene glycol-VS (PEG-VS) crosslinked with decellularized valved conduits (DVC), and to research on its mechanical and biological functions. Methods The valved aortic conduits of rabbits were taken and decellularized by trypsin method and then were crosslinked with 4arm branched PEG-VS to construct the composite scaffolds (CS). The functions of decellularized valved conduits and the composite scaffolds were tested by mechanics test system. Thirty New Zealand white rabbits were equally and randomly assigned to one of the three groups: the control group, the DVC group, and the CS group. Valved aortic conduits, decellularized valved conduits and composite scaffoldswere transplanted into the common carotid artery of the abovementioned three groups of rabbits respectively. Twentyeight days after the operation, patency of the transplants was tested by Color Doppler ultrasound; micromorphology and inflammatory infiltration were observed by hematoxylin eosin（HE） staining andscanning electron microscope (SEM)，and endothelialization of composite scaffolds was detected by immunofluorescent staining. Results A series of biomechanical analyses revealed that the composite scaffolds had highly similar mechanical properties as fresh tissue, and had superior elastic modulus (P=3.1×10-9) and tensile strength (P=1.1×10-6) compared with decellularized valved conduits. Color Doppler ultrasound revealed that the graft patency for the CS group was better than the control group (P=0.054) and the DVC group (P=0.019), and the intraaortic thrombosis rate and distortion rate decreased significantly. HE staining and SEM showed that the endothelialization of composite scaffolds in the CS group was significantly higher than the other two groups with the endothelial cells evenly distributed on the scaffolds. The [CM(159mm]immunofluorescent staining indicated that the positive rate of the endothelial cell marker CD34 was higher than the other two groups. Conclusion The composite scaffolds using 4arm branched PEGVS crosslinked with DVC have great mechanical and biological properties.
Objective To evaluate the difference of oral sodium phosphate (NaP) and polyethylene glycol-electrolyte lavage solution (PEG-ELS) in the aspects of cleansing efficacy, tolerance, and safety in clinical practice, so as to provide evidence for clinical practice. Methods A systematic review of all the relevant randomized controlled trials (RCTs) was performed according the handbook of the Cochrane Collaboration. RCTs were identified from The Cochrane Library(Issue1,2004) MEDLINE(1980-2004), EMBASE(1984-2004),and CBM(1978-2004).Handsearching was also performed .RCTs comparing the two methods were selected .Tow reviewers independently assessed the quality of included trials and extracted data independently .Results Eighteen trials involving 3668 patients were included .Sub-group analysis was performed. Nap tablet had higher rate of adequate cleansing quality (RR1.08,95%CI1.02 to 1.05,p=0.01).Two-day ,divided-dose oral Nap was superior in the rate of adequate cleansing quality (RR1.27,95%CI1.06 to 1.52,p=0.009). .The. rate of adequate cleansing quality in right colon of Nap was lower than PEG-ELS(RR0.79,95%CI 0.64 to 0.98,p=0.03).The rate of abdominal cramps (RR 0.84,95%CI 0.72 to 0.99),the rate of abdominal fullness (RR 0.48,95%CI 0.26 to 0.89),the rate of nausea (RR 0.65,95%CI 0.56 to 0.76)and the percentage of patients who didn’t finished their prescribed regimen (RR 0.23,95%CI0.14 to 0.36)in Nap group were lower (plt;0.05).Conclusions Compared with PEG-ELS,Nap is superior in cleansing efficacy , patients’ tolerance ,safety and economy . It is possible to promote the use of Nap in clinical practice in China .
Objective To prepare a new sirolimus drug-coated polypropylene (SRL-PP) mesh by grafting he sirolimus onto the surface of the polypropylene (PP) mesh via chemical reaction, and to apply the new mesh to animal experiment to explore its anti-adhesion properties.MethodsThe sirolimus was grafted onto the surface of the mesh by chemical reaction to prepare the SRL-PP mesh, which was compared with the PP mesh and the polyethylene glycol modified polypropylene (PEG-PP) mesh. The three groups of meshes were respectively characterized (infrared spectroscopy test, contact angle measurement), and their tensile property was measured. These meshes were implanted into the abdominal cavity of the rats respectively. The anti-adhesion properties of the new sirolimus drug-coated mesh was studied by intraperitoneal adhesion and histopathological change in rats.ResultsThe results of infrared spectrum analysis showed that there was a new absorption peak at the wavelength 1 643 cm–1 (amide group) of SRL-PP mesh, suggesting that sirolimus drug was successfully uploaded onto the surface of the mesh; the SRL-PP mesh was excellent in hydrophilicity, which provided a favorable condition for the growth of peritoneal mesothelial cells. There was no significant difference in mechanical properties between SRL-PP mesh and PP mesh or PEG-PP mesh, which provided a good mechanical guarantee for clinical application. The degree of abdominal adhesion in SRL-PP mesh group (1.00±0.58) was significantly lower than that in PP mesh group (5.17±0.69) and PEG-PP mesh group (4.00±0.58), and the tD value between SRL-PP mesh group and PP mesh group was 2.76 (P<0.05). The number of inflammatory cells and the expression of inflammatory cytokines in the adhesion tissue in SRL-PP mesh group were significantly lower than those in PP mesh group and PEG-PP mesh group.ConclusionsThe sirolimus is successfully loaded onto the surface in the PP mesh by chemical reaction. Animal experiment shows that the sirolimus drug-coated mesh can significantly reduce the abdominal adhesion of the rats, which provides a basis for clinical trial and application.
Objective To evaluate the strength of polyethylene l inercement interface when cementing a new linerinto a fixed acetabular cup in revision. Methods Twenty-five pairs of metal acetabular cups with polyethylene l iners were randomly divided into 5 groups: 1 group with standard locking device as control group (group A), other l iners were cemented into acetabular cups as 4 experimental groups. According to different intersection angles of metal acetabular cups with polyethylene liners and the polyethylene l iners with or without metal ball, the 4 experimental groups were no ball 0° group (group B), 0° group (group C), 10° group (group D), and 20° group (group E), metal acetabular cups intersected with polyethylene liners without metal ball in group B, with metal ball in groups C, D, and E, respectively. The lever-out biomechanical test reproduced in vivo failure mechanism was then performed to evaluate the lever-out failure strength of l iner-cement-metalcup interface. Results The values of l iver-out failure force were (626.68 ± 206.12), (915.04 ± 197.49), (449.02 ± 119.78),(814.68 ± 53.89), and (1 033.05 ± 226.44) N in groups A, B, C, D, and E, respectively, showing significant differences forcomparison among groups (F=8.989，P=0.000). The values of l iver-out failure force in groups B and E were significantlyhigher than that in group A (P lt; 0.05), but no significant difference was found between groups C, D and group A (P gt; 0.05).Conclusion Cementation of polyethylene l iner into a malposition shell meeting within 20° can provide enough fixed strength.
Electric field stimulation (EFS) can effectively inhibit local Ca2+ influx and secondary injury after spinal cord injury (SCI). However, after the EFS, the Ca2+ in the injured spinal cord restarts and subsequent biochemical reactions are stimulated, which affect the long-term effect of EFS. Polyethylene glycol (PEG) is a hydrophilic polymer material that can promote cell membrane fusion and repair damaged cell membranes. This article aims to study the combined effects of EFS and PEG on the treatment of SCI. Sprague-Dawley (SD) rats were subjected to SCI and then divided into control group (no treatment, n = 10), EFS group (EFS for 30 min, n = 10), PEG group (covered with 50% PEG gelatin sponge for 5 min, n = 10) and combination group (combined treatment of EFS and PEG, n = 10). The measurement of motor evoked potential (MEP), the motor behavior score and spinal cord section fast blue staining were performed at different times after SCI. Eight weeks after the operation, the results showed that the latency difference of MEP, the amplitude difference of MEP and the ratio of cavity area of spinal cords in the combination group were significantly lower than those of the control group, EFS group and PEG group. The motor function score and the ratio of residual nerve tissue area in the spinal cords of the combination group were significantly higher than those in the control group, EFS group and PEG group. The results suggest that the combined treatment can reduce the pathological damage and promote the recovery of motor function in rats after SCI, and the therapeutic effects are significantly better than those of EFS and PEG alone.
Objective To investigate the therapeutic effect of the chitosan/polyethylene glycols-succinate/ mitomycin C (CH/PEG-SA/MMC) film on epidural scarring tissues. Methods According to a specific proportion of respective materials, the film of CH/PEG-SA/MMC was developed under some condition. Thirty SD rats were selected and randomized into 6 groups with 5 rats in each group. A rat model of lumbar laminectomy was used. The amount of 20 mg of the CH film was implanted into the animals in group I, 20 mg of CH/PEG film in group II, 20 mg of CH/PEGSA film in group III, 0.05 mg/mL of the MMC soaking for 5 minutes in group IV, 20 mg of CH/PEG-SA/MMC film in group V, and nothing was done in group VI. Specimens were harvested 4 weeks after the above procedures and were then subjected to immunohistochemical and histological examinations to compare their therapeutic effects on epidural cicatricial tissues. Results All rats were in good conditions after operation, without gait abnormal ity, restlessness, infection and death. There was no significant difference among the 6 groups in the postoperative Rydell score (P lt; 0.05). The content of hydroxyprol ine in groups I, II, III, IV, V and VI was (0.570 8 ± 0.345 0), (0.728 6 ± 0.150 6), (0.553 4 ± 0.122 3), (0.313 3 ± 0.106 4), (0.261 9 ± 0.102 1)and (1.020 1 ± 0.120 6) μg/ mg, respectively. There was a significant difference between groups IV, V and groups I, II, III (P lt; 0.05), and there was significant difference between group VI and the rest 5 groups (P lt; 0.05). According to the histological observation, group V had less collagenous fiber parallel ing the dura mater, with few inflammatory cells infiltration, with few capillary vessels and no reaction of macrophages. Conclusion CH/PEG-SA/MMC films can effectively reduce the amount of Hyp in epidural scarring tissues after lumbar laminectomy and therefore is a good treating method in preventing scarring tissue adhesion.
Objective To investigate the effect of polyethylene glycolbovine hemoglobin (PEG-bHb), which was used as an oxygen carrier in cardioplegic solution, on the protection of isolated rat hearts. Methods The hearts of 32 male SD rats were harvested and transferred to Langendorff circuit. They were divided into 4 groups according to cardiocplegia: St.Thomas group (group A), 1∶2 PEG-bHb group (group B), 1∶4 PEG-bHb group (group C) and 1∶8 PEG-bHb group (group D). After 20min balance period, hearts were perfused with cold (4℃) cardioplegic solutions, and preserved at 30℃ for 60min, then reperfused. Levels of cardiac troponin I (cTn I) and adenosine triphosphate(ATP) contant in coronary effuent were detected, and ultrastructures of myocardium were observed. Results After reperfusion, cTn I contant of group A were higher (F=52.955,Plt;0.05) and ATP contant were lower (F=68.757,Plt;0.05) than those in group B, group C and group D. Myocardial water contant were lower in group B and group C(F=3.048,Plt;0.05). Conclusion PEG-bHb in cardioplegic solutions can provide better myocardial protection during ischemia.
