BACKGROUND:Compared with traditional hydrogels, intel igent hydrogels can appear to exhibit different responses to different stimuli such as temperature, pH value, light, and magnetic field, produce two-stage structure and alter chemical structure to generate the ordered supramolecular structure by self-assembling, and ultimately cause the formation of the gel with three-dimensional structure.
OBJECTIVE:To review the research status of intel igent hydrogels and its application in tissue engineering.
METHODS:A computer-based search of CNKI and PubMed databases was performed to retrieve articles addressing intel igent hydrogels in tissue engineering published before 2014. The keywords were“hydrogel, tissue engineering”in Chinese and English.
RESULTS AND CONCLUSION:Intel igent hydrogels are classified into temperature sensitivity, pH sensitivity, photosensitivity, magnetic susceptibility and temperature/pH dual responsive hydrogels. The change of the external environment can be automatical y detected and responded. Intel igent hydrogels exhibit a series of outstanding performances in drug delivery systems, drug delivery, repair and improvement of defected tissues, which are not possessed by traditional materials. In particular, the intel igent hydrogels show considerable superiorities in tissue engineering, including low immunogenicity that reducing inflammation and rejection, biodegradability, realizing the three-dimensional scale simulation of cel microenvironment that is conducive to cel adhesion, growth, migration and differentiation.

Objective To evaluate the safety of a self-made vena cava stent-filter(VCSF)for prevention of pulmonary embolism.Methods Fusiform unmbrella-like vena cava filter was made of Nitinol wires and stainless steel metal pole,and then ten mongrel dogs were implanted with these self-made filters and divided into 5 groups according to the different periods(2,3,4,5 and 6 w) of filter placement,with 2 dogs in each group.After the VCSFs were placed in inferior vena cava via the right femoral vein approach,the dogs in each group were bred for 2-6 weeks,respectively.The blood flow of inferior vena cava and the position of the filters were inspected by inferior vena-cavography according to the indwelling periods.Finally the metal pole was retrieved via the femoral vein,leaving the VCSF as permanent venous stent.The feasibility of retrieval and the free state of filter net with the adhering vascular wall were evaluated.Laparotomies were performed to remove the inferior vena cava from the animals for gross and electron microscopic examinations of the inferior vena cava intimal changes of the involved segment.Results All 10 VCSFs were placed at the right positions of the dogs successfully.Angiography showed patent inferior vena cava without filter thrombosis at 2-6 weeks.There were no tilting and migration of the filter and all the metal poles were successfully retrieved.The superior and inferior extremities of filter nets could be set free with all the filters turning into venous stents.Postmortem displayed retroperitoneal hemorrhage and caval thrombosis.The barbs of the filters penetrated over the caval adventitial coat.Under electron microscope,a thin layer of neointima already covered the braiding net of VCSFs at 2 weeks after the deployment.The tunica intima became slightly thick at 3-4 weeks and with moderate proliferation at 5-6 weeks.Conclusions The self-made vena cava stent-filter possesses rather long indwelling period according to the necessity of treatment with simultaneously keeping patent caval flow,stability of the position and easy for displacement and retrieval.

Objective To explore the mechanism of protective immunity against Schistosoma japonicum infection induced by Sj26 gene transfected dendritic cell(DC).Methods 48 BALB/c mice were divided randomly into 4 groups with 12 each.The mice were injected through auricle for three times with Sj26 gene transfected DC(Group A),pcDNA3 transfected DC(Group B),untreated DC(Group C) and RPMI-1640(Group D) respectively,and challenged with 40?2 cercariae of S.japonicum per mouse 2 weeks after the last immunization.Sera from mice were examined for IgG antibody,IFN-? and IL-4 by ELISA.Western blot was used for detecting specific anti-Sj26 IgG antibody.The production of IFN-? and IL-4 in the supernatant of spleen cells stimulated with soluble egg antigen(SEA) and ConA was quantified by sandwich ABC-ELISA.The proliferation of spleen cells were measured with MTT method.Results IgG antibody increased significantly in the mice of group A at 2 weeks after the last immunization(absorbency A491=0.117),higher than that of group B(A491=0.061) and group C(A491=0.058)(P

Telomerase, as a highly specific ribonucleoprotein, is composed by the RNA template and protein subunits. It can delay or prevent the process of disc degeneration by maintaining telomere length homeostasis as well as affecting the p53-p21-pRb pathway, p16Ink41-pRb pathway and Wnt/β-catenin signal pathway. Telomerase can regulate the senescence and apoptosis of intervertebral disc cell, expected to prevention and repair reconstruction of the structure by telomerase gene therapy of intervertebral disc degeneration.

Objective To compare a potential role of dendritic cells (DCs) and macrophages in inducing protective immunity against infection with Schistosoma japonicum. Methods DCs and macrophages were pulsed in vitro with soluble egg antigen (SEA) of S. japonicum. BALB/c mice were injected three times with DCs or macrophages, either antigen-pulsed or not,and challenged with 40 ± 2 cercariae of S. japonicum per mouse. Worms were collected 42 days later by portal perfusion of the mice and egg number of liver was calculated. To evaluate whether protective immunity had been induced by preparations of DCs or macrophages, the worm burden and fertility ( eggs per female per mouse liver) were compared between the groups of mice. The antibody level against SEA was detected by ELISA. Results With respect to mice injected with untreated cells, numbers of worms and eggs per female worms were significantly reduced in the groups of mice having received pulsed DCs (26. 3% and 37.9%, respectively), or pulsed macrophages (22. 0% and 30.7%). Untreated DCs and macrophages induced no significant effects. The antibody level against SEA rose in sera of all groups of mice up to 42 days after the challenge, but most pronounced in those immunized with pulsed DCs, although this was not significantly different from other groups. Conclusion The results suggest that the protective immunity against S. japonicum might be induced by DCs to a higher extent than by macrophages after in vitro pulsing with egg antigen.

Objective:To prepare old tea buccal tablets using wet granulation method and optimize the preparation technology. Methods:The amount of each adjuvant was studied by single factor experiments, and the formula of the buccal tablets was optimized by the orthogonal experiments using taste and disintegration time as indices. Results:The optimal formula was composed of old tea ex-tract 30 g,mannitol 60g,PEG6000 20 g,aspartame 10 g,citric acid 10 g and menthol crystal 1 g. All the tested indices including ap-pearance, hardness and disintegration time met the requirements described in Chinese pharmacopeia. Conclusion: The preparation technology is reasonable and feasible for the industrial production.

Objective:To establish the quality standard for Sipunculus nudus polysaccharide. Methods:The water content, igni-tion residues and heavy metals in Sipunculus nudus polysaccharide were determined. Authrone-sulfuric acid colorimetry was used to de-termine the polysaccharide content. Results: The water content in the polysaccharide should not exceed 5. 0%, ignition residues should not exceed 1. 0%, and the content of heavy metals should not exceed 20 ppm. The polysaccharide content should exceed 80%( glucose) . Conclusion:The method is accurate and simple, and can be effectively used in the quality control of polysaccharide in Sipunculus nudus Linnaeu.

Objective To observe the regulatory effect of acupotomy lysis on SP level in spinal cord and tissues above spinal cord of rats with knee osteoarthritis.Methods 60 healthy SD rats were randomly divided into normal control group,model group,electro-acupuncture(EA)group,and acupotomy lysis(AL)group.Mix 4%papain solution with 0.3 mol/L cysteine solution in the ratio of 1∶1.After pausing for 0.5h,inject the mixture,20 μl each time,into the left knee joint cavities of rats in model,AL,and EA groups on the day of 1,4,7.After 4 weeks AL group was treated with acupotomy lysis and EA group with electro-acupuncture.Three weeks after treatment,take samples of spinal cord,midbrain,pituitary gland,thalamus,and hypothalamus from the swellings of rats'waists.Measure the content of SP therein separately.Results Compared with normal control group,there was a significant rise in the content of SP in spinal cord and the tissues above spinal cord of model group rats (P＜0.05,P＜0.01),and there was a significant rise in spinal cord,pituitary gland,thalamus and hypothalamus of EA group rats (P＜0.05,P＜0.01);in AL group,there was a significant rise in spinal cord,pituitary gland,thalamus,and there was no statistically difference in hypothalamus and midbrain.Compared with normal control group,there was a significant rise in spinal cord (P＜0.05)and a significant decrease in the SP contents in hypothalamus(P＜0.05,P＜0.01)in EA group.There was no statistically difference between EA group and AL group except in hypothalamus(P＜0.05).Conclusion Acupotomy lysis has positive functions in regulating SP content in centrum of rats with knee osteoarthritis,which helps easing pain.

Objective To investigate the radioprotective effect of cimetidine on survival rate and hematopoietic system in acutely irradiated mice.Methods The total body irradiation doses were 6.0Gy and 8.0Gy respectively at 1.01Gy/min rate. Sixty healthy male C57BL/6 mice were randomly divided into control group, model group, positive-drug (523) group and cimetidine groups (33.3mg/kg, 100mg/kg and 300mg/kg). Each group had ten mice. The mice were given intragastric administration of cimetidine for 6d before the irradiation in cimetidine groups, and 523 was administered before irradiation once a day for one day in 523 group, and at 5h after irradiation, was given again. The 30d survival rate after 8.0Gy irradiation was recorded. The peripheral blood cells, bone marrow DNA content and frequency of micronucleated polychromatic erythrocytes (fMNPCE) were determined 30d after 6.0Gy irradiation.Results After 8.0Gy irradiation, all the mice died on 21th day in model control group. The survival rates in cimetidine groups were 50%, 20% and 30%, respectively. After 6.0Gy irradiation on 30th day, compared with control group, the peripheral white blood cells (WBC) and bone marrow DNA content were decreased significantly (P<0.01,P<0.05) in model group, and fMNPCE was increased significantly (P<0.05). Compared with model group, WBC was significantly increased in 300mg/kg cimetidine group (P<0.01). In cimetidine groups, the bone marrow DNA content was increased significantly after irradiation (P<0.01 orP<0.05), and the fMNPCE was decreased significantly (P<0.01 orP<0.05) and tended towards normal.Conclusion Cimetidine could improve 30d survival rate of acutely irradiated mice and has good protective effect on hematopoietic system.

Objective:To investigate influencing factors of dental caries among 3 to 5-year-old children in the Yuhua District of Changsha by Cariostat detection and provide evidence to prevent caries.Methods:1 032 children aged 3-5 years old from 6 kindergartens in Yuhua District of Changsha were randomly selected for oral health examination. 565 children in 6 large classes, 6 middle classes and 6 small classes were randomly selected from 6 kindergartens were perfected caries activity test (CAT) by Cariostat detection.Results:Among 1 032 children, 626 had caries, the caries rate was 60.66%, the caries was 2.87±3.67, and the caries filling rate was 8.53%. The caries rate of maxillary central incisors was the highest (37.89%), followed by mandibular second primary molars (32.56%) and mandibular first primary molars (32.36%). There was significant difference in caries rate among different age groups (χ 2=9.231, P<0.05). The caries rate of 5-year-old children was the highest (66.50%). 1 032 children were divided into 4 groups according to dmft (decayed, missing, filled teeth) value, and the number of caries free group was the largest; the number of caries in the middle caries group was the least. The number of missing teeth in 1 032 children with caries was 2 959. The number of missing teeth in the high caries group was the most, up to 1 861, accounting for 61.89% of the total number of missing teeth. The analysis of 565 children by CAT showed that the caries rate was different in different CAT grades (χ 2=27.390, P<0.05). The caries rate in the high-risk group was the highest, 90.48%. The CAT value was positively correlated with caries ( r=0.261, P<0.05). Conclusions:The incidence of dental caries in children aged 3-5 years in Yuhua District of Changsha was 60.66%. Cariostat method can truly reflect the situation of caries in children and is helpful to screen the population susceptible to caries in children.