Objective To provide a fixtures and feasible injection method for rat tail vein injection.Methods SD rats were randomly divided into A group and B group,thirty rats in each group.Rats in group A fixed by a simple and practical experimental rats fixtures.And rats in group B fixed by common plastic drink bottles.Then the tail vein injection experiment was conducted respectively.Results It took one people 31.2 seconds in group A and 33.1 seconds in group B to finish the experiment from capture to fix rats,and took one people 68.4 seconds in group A to finish the experiment from capture to finish the injection,while it couldn't finish in group B.It took two people 25.4 seconds in group A and 25.8 seconds in group B to finish the experiment from capture to fix rats,and took 63.7 seconds in group A and 85.6 seconds in group B to finish the experiment from capture to finish the injection.Conclusion The experimental rats fixtures can increase the success rate of rats tail vein injection,and shorten the injection time.It is a safe and effective method.

OBJECTIVEThe super-high-molecular-weight poly-DL-lactic acid (PDLLA), with the molecular weight of 900 kD, is a newly emerging biomaterial and potentially used in the therapy of bone fracture because of its excellent mechanical property. However the biocompatibility of this material has not been reported so far, therefore this experiment was designed to examine whether the super-high-molecular-weight PDLLA was harmful to creatures, when it was implanted in the body of animals for a long period.

METHODSThe material was prepared in small cuboids, with the size of 1.0 mm x 1.5 mm x 2.0 mm, and these blocks were implanted into the masseteric space of SD rats and, the activity of the SD-rats was monitored continuously. The animals were sacrificed in the 3rd, 6th, 9th, 12th months after the operation and, the specimens were taken out from the animals. The examination included anatomical, pathological and haematological methods. The data were analyzed with SPSS 8.0.

RESULTSThe wound healed well after the operation. Super-high-molecular-weight PDLLA degraded 6 months after the implantation. In the 3rd month after the operation, a thin fiber membrane around the materials was formed. In the 6th month, the membrane was much thinner than that in the 3rd month and completely disappeared in the 9th month. The pathological examination showed that slightly inflammatory reaction appeared in the tissue around these blocks in the 3rd month, but the inflammatory reactions were gradually remitted in the following 6th, 9th and 12th months. Further, the haematological examination did not show any abnormity during the 12-month observation period.

CONCLUSIONThe super-high-molecular-weight PDLLA can be degrade when it is implanted into the body of creatures, which proves its good biocompatibility.

Animals ; Biocompatible Materials ; chemistry ; metabolism ; Biodegradation, Environmental ; Bone Substitutes ; Implants, Experimental ; Lactic Acid ; chemistry ; metabolism ; Male ; Mandible ; metabolism ; surgery ; Molecular Weight ; Polyesters ; Polymers ; chemistry ; metabolism ; Rats ; Rats, Sprague-Dawley

A new technique was developed to fabricate PDLLA and PDLLA/PELA composite scaffolds by thermally induced phase separation in combination, with particulate-leaching. Effects of PDLLA/PELA ratio, PEG/PLA ratio and PEG molecular weight on properties of mechanics, degradation behavior and cell toxicity as well as morphological properties were investigated. As the result showed, by thermally induced phase separation/ particulate-leaching, a unique morphology that macropores (100-250 microm) and micropores (5-40 microm)coexisted in the scaffold was obtained. An increase of PEG content or a decrease of PEG molecular weight raised the porosity of the scaffold. A decrease of PDLLA/PELA ratio or an increase of PEG/PLA ratio weakened mechanical properties and accelerated the degradation of the scaffold. PDLLA and PDLLA/PELA scaffolds didn't show cell toxicity. When PDLLA/PELA ratio was 3:1 and PEG5000/PLA ratio was 25:75, the scaffold got a regular, highly interconnected, macro-co-micro porous structure.
Biocompatible Materials ; chemistry ; Lactates ; chemistry ; Lactic Acid ; chemistry ; Polyesters ; Polyethylene Glycols ; chemistry ; Polyglycolic Acid ; chemistry ; Polymers ; chemistry ; Porosity ; Surface Properties ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry ; Water ; chemistry

OBJECTIVETo evaluate the biocompatibility of the super high molecular weight poly D,L-lactic acid (SHMW-PDLLA) implant.

METHODSThe SHMW-PDLLA plates were implanted into the SD-rats between the masseter and ramus of the mandible. The blood specimens were gained at 3, 6, 9, 12 months after the operation. The proteins, electrolyte, enzyme and other indices were tested by use of Beckman automatic biochemical analysis device. The soft tissue specimens around the SHMW-PDLLA plates were gained at 3, 6, 9, 12 months after the operation and the tissue reaction was observed with the pathological and haematological methods.

RESULTSThere were not any abnormal findings in the blood after the SHMW-PDLLA plates implanted in the body of SD-rats. The implanted SHMW-PDLLA plates were degraded gradually in 6 to 12 months after the operation. There was not any abnormal tissue reaction found to the soft tissue around the SHMW-PDLLA plates by histological and pathological observations.

CONCLUSIONSThe SHMW-PDLLA implant has a good biocompatibility to SD-rats.

Animals ; Biocompatible Materials ; chemistry ; Bone Plates ; Lactic Acid ; chemistry ; Mandible ; Molecular Weight ; Prostheses and Implants

This study was designed to assess the effect of implantation site and environment on early in vivo degradation behaviors of poly(L-lactide) (PLLA) and poly(L-lactide-co-glycolide) (PLGA) copolymer. The rods were implanted at two sites in each of 24 New Zealand White rabbits. The first site was within the suprapatellar bursa of the joint cavities (JC) and the second site was in the opposite condyles of femurs (CF). Three rabbits of each group underwent explantation of rods after 4, 8, 12, and 16 weeks. At each interval, measures were taken to evaluate the molecular weight, shear strength, weight loss and thermal properties of PLLA and PLGA. It was found that PLGA degraded slightly faster than PLLA. After 16 weeks, PLLA's initial inherent viscosity of 4.6 decreased to about 3.4 in both implantation sites while that of PLGA decreased from 4.6 to about 2.2. Both PLGA and PLLA showed enough shear strength retention in 16 weeks (> or = 53MPa) within 16 weeks. Autocatalysis mechanism was confirmed by the fact of accelerated weight loss of PLGA after 8 weeks and of PLLA after 12 weeks. The results revealed that PLGA could be a promising candidate material as a replacement of PLLA in internal fixation of bone fractures, and no significant difference of early in vivo degradation behaviors between PLLA and PLGA was observed in regard to different implantation sites in 16 weeks.
Absorbable Implants ; Animals ; Bone Nails ; Female ; Implants, Experimental ; Internal Fixators ; Lactic Acid ; chemistry ; metabolism ; Male ; Polyesters ; Polyglycolic Acid ; chemistry ; metabolism ; Polymers ; chemistry ; metabolism ; Rabbits

Amine-terminated poly (ethylene glycol) (PEG) was prepared by two steps. Firstly, potassium naphthalene was added to a solution of methoxypolyethylene glycol 5,000 in benzene until the solution maintains green in half of an hour, then excess tosylchloride was introduced; secondly, the conversion of the tosylate into an amine was carried out by Gabriel synthesis. The block copolymer poly (ethylene glycol)-co-poly (gamma-benzyl L-glutamate ) could be obtained by ring-opening polymerization of gamma-benzyl-L-glutamate N-carboxy anhydride with amine-terminated PEG as macroinitiator. And the benzyl group could be removed by sodium hydroxide. The product structure was characterized by IR, 1HNMR, GPC. The cisplatin-loaded micelle was observed by transmission electron microscope (TEM). And the block copolymer is expected to be useful as functional materials including carrier systems in drug controlled delivery applications.
Drug Carriers ; Polyethylene Glycols ; chemical synthesis ; Polyglutamic Acid ; Polymers ; chemical synthesis ; chemistry ; Surface Properties

The aim of this study was to develop a bioactive membrane for inducing bone regeneration. The membrane was composed of polylactic acid, collagen, recombinant human bone morphogenetic protein-2 (rhBMP-2). The PLA + collagen + rhBMP-2 membrane was fabricated by solvent-casting and cool-drying. The mechanic properties of this compound membrane were tested. The two surfaces of membrane were observed by SEM. Degradability of PLA was evaluated by SEM observation and molecular weight measure in vitro and in vivo. The compound membranes were implanted in rabbit muscles. The samples were obtained when animals were sacrificed at different periods: 2 weeks, 1, 2, 3, 6 months after surgery. The biodegradability and biocompatibility of the membrane were evaluated. The heterotopic bone inducing activity of BMP was identified. The results indicated that the strength at extension to failure of the compound membrane was 36.4MPa at 2.3% strain. The compound membrane was found bearing active factor on its coarse side, which can induce bone regeneration. After implantation in vivo, the membrane maintained the structure for three months and degraded in 6 months. Based on histological analysis, there was no obvious inflammation. Heterotopic bone was induced. We could conclude that the PLA + collagen + rhBMP-2 membrane is an absorbable compound membrane that possesses good biocompatibility, adequate mechanic properties and excellent property of bone induction. It could be applied as an ideal membrane for inducing bone regeneration.
Animals ; Biocompatible Materials ; Biodegradation, Environmental ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; administration & dosage ; pharmacology ; Bone Regeneration ; drug effects ; Collagen ; administration & dosage ; pharmacology ; Guided Tissue Regeneration ; Lactic Acid ; administration & dosage ; pharmacology ; Male ; Membranes, Artificial ; Polyesters ; Polymers ; administration & dosage ; pharmacology ; Rabbits ; Transforming Growth Factor beta ; administration & dosage ; pharmacology

BACKGROUND:The key to preventing the recurrence of intrauterine adhesions is to reconstruct the endometrium with normal function.The latest breakthrough in the treatment of recurrent intrauterine adhesions in and outside China is the use of degradable materials to prepare hydrogels to prevent the recurrence of adhesions. OBJECTIVE:To review the research advance in hydrogel-promoted endometrial repair in intrauterine adhesions. METHODS:PubMed,Web of Science,China National Knowledge Infrastructure(CNKI),and WanFang databases were searched systematically,with the keywords"intrauterine adhesions,endometrial injury,endometrium regeneration,hydrogel"in Chinese and English.Relevant articles published in each database from January 1990 to March 2023 were collected. RESULTS AND CONCLUSION:In recent years,research on hydrogel-promoted endometrial repair in uterine adhesions in and outside China has made some progress and plays an important role in the prevention and treatment of intrauterine adhesions and the promotion of endometrial repair:(1)As an important carrier in tissue engineering,hydrogel itself has excellent biocompatibility,biodegradability and three-dimensional network structure,which can be better applied in the treatment of intrauterine adhesions.(2)The hydrogel-based carrier system can promote the proliferation and differentiation of endometrial epithelial cells by transporting drugs/biologics/stem cells,and restore normal uterine morphology to prevent adhesion recurrence.(3)Hyaluronic acid hydrogels can not only meet good biocompatibility,but also promote the proliferation and differentiation of endometrial epithelial cells,and will be hydrolyzed by corresponding enzymes in utero,without affecting the normal metabolism of the body.They are currently commonly used uterine anti-adhesion agents in the clinic and are also the most commonly used hydrogel carriers in tissue engineering research.(4)Poloxamer hydrogel with excellent temperature-sensitive properties can rapidly gelate into the body,quickly form a physical barrier,and can play a slow-release effect on carrying substances and provide a platform for cell growth/adhesion.(5)There are broad prospects for the preparation of therapeutic hydrogels using materials with different characteristics,such as temperature-sensitive hydrogels,pH-responsive hydrogels and photosensitive hydrogels,but there are still many problems to be solved,such as the safety of the hydrogel system,whether the degradation products cause immune reactions,and whether they have an impact on the normal body's menstrual period.A large number of animal experiments and clinical trials are needed to verify its safety and efficacy,and continuously improve the treatment strategy.

TSCI have dyskinesia and sensory disturbance that can cause various life-threaten complications. The patients with traumatic spinal cord injury (TSCI), seriously affecting the quality of life of patients. Based on the epidemiology of TSCI and domestic and foreign literatures as well as expert investigations, this expert consensus reviews the definition, injury classification, rehabilitation assessment, rehabilitation strategies and rehabilitation measures of TSCI so as to provide early standardized rehabilitation treatment methods for TSCI.

Periarticular fracture of the shoulder is a common type of fractures in the elderly. Postoperative adverse events such as internal fixation failure, humeral head ischemic necrosis and upper limb dysfunction occur frequently, which seriously endangers the exercise and health of the elderly. Compared with the fracture with normal bone mass, the osteoporotic periarticular fracture of the shoulder is complicated with slow healing and poor rehabilitation, so the clinical management becomes more difficult. At present, there is no targeted guideline or consensus for this type of fracture in China. In such context, experts from Youth Osteoporosis Group of Chinese Orthopedic Association, Orthopedic Expert Committee of Geriatrics Branch of Chinese Association of Gerontology and Geriatrics, Osteoporosis Group of Youth Committee of Chinese Association of Orthopedic Surgeons and Osteoporosis Committee of Shanghai Association of Chinese Integrative Medicine developed the Chinese expert consensus on the diagnosis and treatment of osteoporotic periarticular fracture of the shoulder in the elderly ( version 2023). Nine recommendations were put forward from the aspects of diagnosis, treatment strategies and rehabilitation of osteoporotic periarticular fracture of the shoulder, hoping to promote the standardized, systematic and personalized diagnosis and treatment concept and improve functional outcomes and quality of life in elderly patients with osteoporotic periarticular fracture of the shoulder.