The evaluation of biomaterial biocompatibility is a key step before the clinical application.With the rapid development of molecular biology,scientists have begun to evaluate biomaterial biocompatibility at molecular level and proposed the concept of molecular biocompatibility.Researchers'main tasks at present are to identify more molecular markers using molecular biology technology and to establish standards for evaluating molecular biocompatibility of biomaterial,which will provide the guidance for the design of better biomaterials.

Biodegradable polymers as drug delivery systems have attracted investigators. They degrade in biological fluids to produce biocompatible and nontoxic products, which could be removed from the body by normal physiological pathways without extra surgical removal. In this article, literatures on biodegradable polymers mainly served as matrix in controlled release systems are analyzed and reviewed.

Current trends in nanotechnology and RNA interference technology have made the application of nanocarriers (NCS) as a novel gene and drug delivery systems very promising for the field of multidrug resistance (MDR) cancer treatment. Co-delivery of gene and chemotherapy drugs with NCS has a good synergistic effect compared with the traditional chemotherapy which can increase the amount of the drug distribution in target organ in order to reduce the toxic side effects thereby enhancing efficacy. Therefore, the advent of co-delivery systems with NCS especially in the clinical treatment of MDR has had a significant impact on the cancer treatment.

Guinea pig, pigeon and toad are the vertebrates on different evolution level. The acid phosphatase content in the hepatocytes of centrilobular area and periportal area of hepatic lobules were quantitatively measured by microspectrophotometer and image analyser. The results showed that the content of acid phosphatase of hepatocytes was highest in guinea pig, lowest in pigeon, and toad in between the both. The average density of acid phosphatase distribution in the hepatocytes increases according to the evolution order. The significance of this phenomenon was discussed.

In this paper,the classification,application and advantages of three-dimensional (3D) printing in biomedical engineering are summarized.The working principles of 3D printing,stereolithography,fused deposition modeling,selective laser sintering and 3D spray printing,as well as merits,demerits and recent progress are reviewed.The 3D printing has been widely used in the synthetic of bone tissue engineering scaffolds,with biodegradable and bioactive materials in the scaffold.Synthetic bone materials and surgical simulation by 3D printing technology are increasingly common and has achieved satisfactory results in China.Although 3D printing technology has developed rapidly,development of suitable biomaterials and improving relevant techniques are still urgent issues.Up to now,the functionalization of bionic organs is the most difficult issue,in which the cell co-culture,vascularization and preparation of the scaffolds are problem to be solved.The 3D printing technology will make remarkable achievements for the regeneration and repair of human organ through our efforts.

Objective:To investigate the expression of estrogen receptor ? and ?(ER? and ER?) in temporomandibular joints(TMJs) of Sprague-Dawley rats.Methods:The expression of ER? and ER? in TMJs was examined by SABC technique of immunocytochemistry, meanwhile the co-expression of them was detected by double-staining technique of immunocytochemistry.Results:①Intense ER? and ER? immunoreactivity was localized in the hypertrophic layer of condyle cartilage,and some immunoreactivity was found in osteocytes of mandible and temporal bone. ②The immunoreactivity of ER? and ER? was found in both nuclei and cytoplasms. Most of immunoreactivity of ER? was localized in nuclei, while ER? was distrubuted more evenly. ③The expression of ER? was wider than that of ER?.Conclusions:TMJ is one of target organs of estrogen.The expression of ER? is different from that of ER?,which suggests there may be different mechanisms directed by ERs.

Many factors influence the elastin-like polypeptides (ELPs) self-assembled into micron-sized particles. However, few efforts were made to investigate these factors. Using the ELPs [KV8F]n as the target, we studied systematically the factors with the dynamic light scattering. Our results show that the particle size increased and the uniform of particles decreased with the increase of the molecular weight. The analysis of size variation in self-assembled ELPs in response to changes in salt concentration indicated that the size increased with increasing the salt concentration, and the opposite response was observed when the concentration was above 0.4 mol/L. Under these conditions, the particles are micron-sized and larger than 1.1 μm. However, when the fusions containing the same ELPs and xylanase or 1,3-propanediol oxidoreductase, the size of the self-assembled ELPs particles decreased dramatically, which was only about 1/10 of that of the free ELPs. We proposed that the solvent accessible charged area of the enzymes could interact with the ELPs, the sterical hindrance of the enzymes prevent the aggregation of the ELPs. This might be the most important parameter in altering the particle size sharply.
Elastin ; chemistry ; Molecular Weight ; Particle Size ; Peptides ; chemistry ; Salts ; chemistry

Objective:To investigate the effect of tooth wear on the morphological features of mandibular first molars. Methods:15 extracted mandibular first molars with tooth wear and 15 without wear were investigated. Data about the morphological features of tooth were collected through the general measurement and the image measurement by electronic meter. Results:①In non-tooth-wear group, mesiodistal width of tooth was greater than buccolingual width(P0.05); ②The vertical distance between the lowest point of pulp chamber roof and occlusal surface in non-tooth-wear group was greater than that in tooth-wear group(P05); ④The distance between distolingual pulp horn and distal proximal plane was greater than that between mesiolingual pulp horn and mesial proximal plane in both two groups(P0.05). Conclusion:For different parts of tooth, the effect of tooth wear differs. As for mandibular first molars, the distal part of occlusal surface and the buccal part of distal proximal plane are susceptible to tooth wear, which is mainly due to occlusal factors and the features of biomechanical system.

Objective To assess the effect of the gamma knife radiosurgery (GKS) for acoustic neuromas, and to analyze the MRI features of the tumors after GKS. Methods GKS was performed in 309 patients with acoustic neuromas from December 1994 to December 2002 at our center. The Leksell Gamma Knife models B and C were used. 249 cases with 256 tumors were followed up with MRI, which included 107 males and 142 females. The median age of the patients was 48.7?14.2 years (10-77 years). GKS was applied as primary treatment for 189 cases (75.9%), and was an adjunctive management approach for 60 cases (24.1%). The median clinical follow-up period and radiological follow-up period was (26.4?21.3) months (6-101 months) and (22.4?19.0) months (6-93 months), respectively. Results Of the 256 tumors, 79 tumors (30.8%) regressed, 165 tumors (64.5%) remained stable, 12 tumors (4.7%) enlarged, and the overall tumor control rate was 95.3%. Among 30 tumors of NF-Ⅱ , 8 tumors (26.6%) regressed, 19 tumors (63.4) remained stable, and 3 tumors (10.0%) enlarged, and tumor control rate was 90%. The rate of hearing deterioration was 22.7%, the rate of permanent facial paralysis was 0%, the rate of transient facial paralysis was 5.9%, and the incidence of transient trigeminal neuropathies was 19.9%. On the image of follow-up MRI, 79 tumors (30.0%) showed loss of contrast enhancement (LOE). LOE was the imaging property of neuromas on follow-up MRI, which symbolized a chronic decrease in the vascularity of neuromas. The histological findings of LOE demonstrated radiation-induced tumor necrosis. The transient swelling of tumors could not be confounded with the growth of tumors. Conclusion GKS is confirmed to be an effective treatment for acoustic neuromas and plays an important role in the control of NF―Ⅱ, and GKS can prevent cranial nerve from injury to a great extent.

Objective To evaluate the clinical curative effect of Salvia miltiorrhiza Ligustrazine combined with Butylphthalide in cerebral infarction of children. Methods Sixty-two children with acute cerebral infarction were randomly divided into treatment group (33 patients) and control group (29 patients). The patients in two groups received the same basic treatment. The control group used Salvia Ligustrazine injection, and the treatment group used Salvia Ligustrazine injection combined with Butylphthalide. The total efficiency, the degree of recovery of muscle strength and the scores of nerve defect 2 weeks after treatment were compared. Results The total efficiency in treatment group was 87.9%(29/33), in control group was 75.9%(22/29), and there was significant difference (P<0.05). Two weeks after treatment, the muscle strength scores in treatment group was (4.00 ± 0.47) scores , in control group was (3.59 ± 0.98) scores, and there was significant difference (P<0.05). Two weeks after treatment, the scores of nerve defect in treatment group was (5.42 ± 2.18) scores, in control group was (6.86 ± 2.23) scores, and there was significant difference (P<0.05). Conclusions Salvia Ligustrazine combined with Butylphthalide in treatment of cerebral infarction of children has obvious effect, and it is worthy of spreading.