【Abstract】 Objective To summarize the latest developments in silk fibroin as biomaterials and its appl icationsin tissue engineering. Methods The recent original l iterature on silk fibroin as biomaterials were extensively reviewed,illustrating the properties and appl ications of silk fibroin biomaterials in tissue engineering. Results Silk fibroinas biomaterials had good biocompatibil ity and degradabil ity. It supported the cell adhesion differentiation and growth. It was used for artificial l igament, vessel, bone, nerve and so on. After modification, silk fibroin could be extensively used in tissue engineering. Conclusion Silk fibroin is a good biomaterial, which has a great potential appl ications in tissue engineering.
To evaluate the cytocompatibil ity of Arg-Gly-Asp-recombinant spider silk protein (pNSR16) / poly vinyl alcohol (PVA) through in vitro cytotoxicity experiment and cell-material co-culture experiment. Methods pNSR16/PVA scaffold and its extraction were prepared by using solvent casting/particulate leaching method, and NIH-3T3 cells were cultivated with the extraction in vitro. The cytotoxicity of scaffold was analyzed using MTT assay 1, 3 and 5 days after culture. Scanning electron microscope and HE staining observation were conducted 2, 4 and 6 days after culturing NIH-3T3 cells on the pNSR16/PVA scaffold. Immunohistochemistry detection was performed 6 days after co-culture. Adhesion, growthand expression of the cells on the scaffold were observed. Results The cytotoxicity of pNSR16/PVA scaffold was in grade 0. Scanning electron microscope observation: the cells covered the surface of the scaffold and were arranged in a directional manner 4 days after co-culture. HE staining: the cells adhered to and grew on the surface of scaffold, and migrated into the scaffold with the increase of culture duration. Immunohistochemistry detection: bFGF was secreted by NIH-3T3 cells, and the cells differentiated normally. Conclusion pNSR16/PVA scaffold has a satisfactory cytocompatibil ity and may be an ideal tissue engineered scaffold materia
Objective To investigate the effectiveness and technical points of shortened replantation combined with limb lengthening in the treatment of severe amputation of middle and distal lower leg. Methods Twelve cases of severe amputation of middle and distal lower leg were treated with shortened replantation at the 1st stage and limb lengthening at the 2nd stage between April 2009 and May 2016. There were 9 males and 3 females with an average age of 28 years (range, 16-32 years). The injury causes included traffic accident injury in 4 cases, heavy pound injury in 6 cases, and machine crush injury in 2 cases. The interval from injuries to treatment ranged from 30 minuts to 6 hours (mean, 3 hours and 12 minutes). All of 12 cases, 6 cases were completely amputated in the right middle and distal lower leg, 4 were not completely amputated in the left middle and distal lower leg, and 2 were ankle amputations. The limbs were 4.0-12.5 cm shorter than the contralateral sides, with an average of 7.3 cm. Limb lengthening was performed at 1.5-8.0 months after replantation and the time of extension was 1.7-5.3 months (mean, 3.1 months). Results All 12 patients recovered the same lengths of both lower extremities after shortened replantation and limb lengthening. The lengthened segments gained good bone mineralization, bony union was achieved at lengthened segments and broken end of fracture at 7-16 months (mean, 11.3 months). All patients were followed up 6 months to 5 years (mean, 2 years and 5 months). The range of motion of the knee joint were 0-5° (mean, 3°) in hyperextension and 110-140° (mean, 120°) in flexion. Except for 2 cases of ankle arthrodesis, plantar flexion angles were 15-45° (mean, 26°) and dorsiflexion angles were 10-25° (mean, 15°) in the other cases. The plantar sensation was restored to the S3+ level in 4 cases, S3 level in 6 cases, and S2 level in 2 cases. At last follow-up, the affected limb function were excellent in 7 cases, good in 3 cases, fair in 2 cases according to Kofoed functional evaluation criteria. Conclusion It expanded indications for replantation of lower limb amputation, reduced the operation difficulty and trauma with shortened replantation combined with limb lengthening in the treatment of severe amputation of middle and distal lower leg.
ObjectiveTo analyze the epidemiological burden and change trend of five sexually transmitted infections (STIs) in China from 1990 to 2019. MethodsThe estimated numbers and standardized rates of STIs incidence, prevalence, and disability-adjusted life years (DALY) in China and other regions were obtained from the Global Burden of Disease Study 2019. The epidemic burden and change trend of STIs in China were compared and evaluated. ResultsIn 2019, STIs affected about 242 million people in China, resulting in 173 million new cases and 350 000 person years of DALY losses. Compared with 1990, the prevalence and incidence of STIs increased by 59.75% and 30.02%, respectively, and the number of DALY decreased by 35.19%. From 1990 to 2019, the incidence rate of chlamydia infection and gonococcal infection in the young and middle-aged group (aged 15-49 years) showed an upward trend; in addition, the DALY rate of genital herpes and trichomoniasis also increased. Among the 5 STIs, the disease burden caused by trichomoniasis infection in women was much higher than that in men. With the increase in the socio-demographic index (SDI), the burden of STIs in China gradually decreased. After the SDI exceeded 0.65, the decline rate of standardized DALY rate sharply increased. ConclusionThe disease burden of STIs in China shows a downward trend from 1990 to 2019, and the disease burden of the young and middle-aged group (aged 15-49 years) is the most significant, especially in trichomoniasis and chlamydia infection.