Objective To investigate the characteristics of interactive effects of magnetic field of two intensities combined with high-temperature and noise simulating ship environment. Methods Orthogonal trial design of three factors and two levels and variance analysis method were employed. The rabbits and rats were grouped into eight combined exposure groups and eight controls, respectively, according to orthogonal table L_8 (2~7). Animals in all groups underwent the experiments and the indices were determined at the same time. Results Analysis of the radius of capillary vessels on rabbit's conjunctiva and HSP70 of rat's liver and spleen showed that magnetic field was the dominant factor (P

BACKGROUND:Because of convenient source, multi-lineage differentiation and low immunogenicity, bone marrow mesenchymal stem cels are the ideal cel type to serve as vectors of transgenic cels in pain management. However, the replicative senescence and smal amount of cels obtained from the bone marrow restrict the application of bone marrow mesenchymal stem cels in pain research. OBJECTIVE:To construct human telomerase reverse transcriptase (hTERT)-immortalized rat bone marrow mesenchymal stem cels as transgenic celular vectors for pain therapy. METHODS:Bone marrow mesenchymal stem cels were obtained from whole rat bone marrow, and then transfected with a lentivirus containing the hTERT (pLV-Puro-EF1α-hTERT) folowed by puromycin selection. hTERT expression and telomerase activity in these transfected cels were determined by RT-PCR and TRAP. Morphological changes, capacity of cel growth and multi-lineage differentiation, chromosome karyotype and tumorigenicity were observed in vitro. Moreover, the expression of cel surface molecule, Nestin, MHC-I and MHC-II in transfected cels were also detected by flow cytometry and immunocytochemistry. RESULTS AND CONCLUSION: The bone marrow mesenchymal stem cels geneticaly modified by hTERT could be cultured and passaged through 30 generations in vitro. Compared to the primary and negative transfected cels, the hTERT-modified bone marrow mesenchymal stem cels showed higher expression of hTERT mRNA, telomerase activity and cel proliferation. Most of transfected cels stayed at G2/M and S stages. The proliferation index of the transfected cels were increased dramaticaly. The positive rates of CD29, CD44 and CD90 were over 70%, but the positive rates of CD34 and CD45 were less than 5%. Transfected cels were positive for Nestin in the cytoplasm, but negative for MHC-1 and MHC-11. In addition, this cel line continued to exhibit the characteristics of fibroblastic bone marrow mesenchymal stem cels, including phenotype, differentiation into osteoblasts, adipocytes and neuron-like cels. No chromosome abnormality and tumor formation were observed in this experiment. Taken together, these data suggests that the rat bone marrow mesenchymal stem cels immortalized by hTERT gene are constructed successfuly and stil maintain major stem cels characteristics, which provide safe and stable cel vectors as research base for pain therapy.

A scaffold fabricated with lysine/nerve growth factor (NGF)/poly (lactic acid coglycolic acid) copolymer (PLGA) and acellular pigskin was evaluated in vitro as a potential artificial nerve scaffold. Properties of the scaffold such as microstructure, mechanical property, degradation behavior in PBS and water, Schwann cell adhesion property, and release of NGF were investigated. Results showed PLGA had permeated into the porous structure of acellular pigskin; its breaking strength was 8.308 MPa, breaking extensibility was 38.98%, elastic modulus was 97.27 MPa. The porosities of the scaffold ranged from 68.3% to 81.2% with densities from 0.62 g/cm3 to 0.68 g/cm3. At 4 weeks of degradation in vitro, maximum mass loss ratio was 43.3%. The release of NGF could still be detected on the 30th day, and its accumulative release rate was 38%. Lysine added into the scaffold neutralized the acidoid preventing degradation of PLGA to maintain a solution pH value. Schwann cells had grown across the scaffold after co-cultivation for 15 days. These in vitro properties of the pigskin based composite might indicate its potentiality to be an artificial nerve scaffold.
Acellular Dermis ; Animals ; Biocompatible Materials ; Guided Tissue Regeneration ; Lactic Acid ; pharmacology ; Lysine ; pharmacology ; Nerve Growth Factors ; chemistry ; pharmacology ; Nerve Regeneration ; Polyglycolic Acid ; pharmacology ; Swine ; Tissue Engineering ; Tissue Scaffolds

In recent years, many researchers have devoted themselves to the application of photodynamic therapy (PDT) in root canal disinfection, as conventional root canal disinfection methods have failed to achieve the optimal effect. Some clinicians have also applied PDT to root canal disinfection. PDT is expected to have a better effect than traditional root canal disinfection. This paper reviews the research progress on the mechanism, effect, influencing factors and limitations of PDT in root canal disinfection. Current research suggests that differences in the type and status of the bacteria, photosensitizers, light sources, operating environment and methods all affect the efficacy of root canal disinfection of PDT. Most of the research into PDT for root canal disinfection finds that it is effective, nontoxic, advantageous to dental pulp regeneration and comfortable for the patient, as well as lacking an excitant; however, its bactericidal effect is inferior to that of sodium hypochlorite. At present, it cannot replace traditional chemical washing but is a promising auxiliary method. The design of the photosensitizer, the energy dose of the light source and the optimal irradiation time need to be determined by further experiments, and more clinical verification is needed before its application in root canal therapy.

Objective:To establish the biology reference interval (RI) of peripheral blood procalcitonin (PCT) for children between 3 days and 6 years old in China.Methods:Totally 3 353 reference individuals with apparent health or no specific diseases were recruited in 18 hospitals throughout the country during October 2020 to May 2021. Reference individuals were divided into four groups: 3-28 days, 29 days - 1 year, 1-3 years and 4-6 years. Vein blood or capillary blood were collected by percutaneous puncture from every reference individual. The PCT level in serum and the capillary whole blood were assayed by Roche Cobas e601 and Norman NRM411-S7 immunoanalyzer. Outliers were deleted and 95th percentiles of every group were provided as RIs. Man-Whitney U test or Kruskal-Wallis test were used performed to assess the difference among different gender, age or method groups. Results:The difference of PCT distribution between male and female is not statistically significant, but the difference between serum and capillary whole blood is statistically significant. The differences between age groups are significant too. For Roche e601, serum PCT RI of 3-28 days group is <0.23 μg/L, 29 days - 6 years are <0.11 μg/L. For NRM411, Serum PCT RI of 3-28 days group is <0.21 μg/L, 29 days - 1 year: <0.09 μg/L, 1 - 6 years: <0.10 μg/L. For whole blood PCT, RI of 3-28 days group is <0.26 μg/L, 29 days - 6 years is <0.15 μg/L.Conclusions:Serum and capillary whole blood PCT have different RIs, however, capillary whole blood PCT testing is valuable in pediatric application. Children in 3-28 days show higher PCT levels than other age group. To establish the RIs and understand the differences among different groups are essential for the interpretation and clinical application of peripheral blood PCT testing results.