Objective To study the role of chimerism on immune tolerance to cardiac allografts. Methods Male DA rat hearts were transplanted to male Lewis rats using Ono’s model and randomly divided into three groups: normal control group (group Ⅰ), rejection group (group Ⅱ), immune tolerance group (group Ⅲ). Mean survival time (MST), histological changes, mixed lymphocyte reaction (MLR), chimerism of recipients’ spleen and thymus were measured after operation. Results The MST of cardiac allografts in group Ⅲ (85.28±7.48 d) was significantly longer than that in the group Ⅱ (7.33±1.03 d). Only a few inflammatory cells infiltrated in cardiac allografts in group Ⅲ. MLR of group Ⅲ were significantly decreased compared with those of group Ⅰ (Plt;0.01). Conclusion The chimerism of recipient plays an important role on immune tolerance to cardiac allografts.
Objective To study the relationship between Th1/Th2 cytokines messenger ribonucleic acid (mRNA) expression and immune tolerance to cardiac allografts in rats. Methods Male DA rat hearts were transplanted to male Lewis rats using Ono’s model and randomly divided into three groups: control group, rejection group, and tolerance group (each group 10 rats). Mean survival time (MST), histological changes, mRNA expression level of Th1/Th2 cytokines interleukin-2 (IL-2), interferon-γ (IFN-γ), interleukin-4(IL-4), interleukin-10(IL-10) were measured. Results MST (85.28±7.48 d) of heart allografts in tolerance group was significantly longer than that(7.33±1.03 d) in rejection group. Only a few inflammatory cells infiltrated in cardiac allografts in tolerance group. The mRNA expression of IL-2, IFN-γ (Th1 cytokines) in rejection group were much ber than those in control group, and in tolerance group were much lower; mRNA expression of IL-4, IL-10 (Th2 cytokines) in rejection group were much ...更多lower than those in control group,and in tolerance group were much ber than those in control group. Conclusions The dynamic equilibrium of Th1/Th2 cytokines is very important in immune tolerance. The deviation of Th1 to Th2 is one of the mechanisms in immune tolerance.
OBJECTIVE To compare the permeability and incidence rate of complication of arteriovenous internal fistula made by autogenous, homologous, and artificial Teflon blood vessels. METHODS Two hundred and forty one cases with arteriovenous internal fistula made by autogenous, homologous, and artificial Teflon blood vessels were followed up to compare the permeability and incidence rate of complication at 6 months, 1 year, 3 years, and 5 years. RESULTS The incidence rate of complication of autogenous blood vessels was lowest, it had no statistical differences compared with arteriovenous internal fistula made by homologous blood vessels. The permeability of arteriovenous internal fistula made by homologous blood vessels was highest, and it had no statistical differences compared with autogenous blood vessels. The permeability of arteriovenous internal fistula made by artificial Teflon blood vessels was lowest, but the incidence rate of complication was highest, and it had significantly statistical differences compared with arteriovenous internal fistula made by autogenous blood vessels (P lt; 0.01). CONCLUSION Arteriovenous internal fistulas made by autogenous and homologous blood vessels have high permeability and low incidence rate of complication, they are superior to the arteriovenous internal fistula made by artificial Teflon blood vessels.
In order to compare the immunogenecity and biological properties of homologous tendon grafts after treatment from different methods of freezing, tendons from chickens received repeated freezing-thawing treatment or ultra-low-temperature treatment, and then, the post-treatment tendons were preserved in liquid nitrogen for 3 months before transplantation. The autogenous tendon transplantation was served as the control. It was found that in the group of repeated freezing-thawing treated tendons, the tendon cells all died and while in the ultra-low temperature treated tendons the active rate of tendon cells was 92.5% +/- 3.4%, and the histological observation showed that transplantation of frozen tendons would result in extensive infiltration of inflammatory cells in the grafted tendons and the peritendinous adhesion was serious than that of the autografts. The active flexion function, hydroxyproline levels and the biomechanical analysis showed no significant differences between the repeated freezing-thawing treated homografts and the ultra-low-temperature treated homografts, and that the autografts was definitely superior to the homografts. The conclusions were: (1) Transplantation of the homologous tendons from the two different methods of freezing could receive considerable success and there was no significant difference between them; (2) Transplantation of frozen homologous tendon graft might give successful result which was probably due to the preservation of the cellular activity of the tendon cells following freezing treatment and elimination of the antigen presenting cells in the tendon as well, and (3) Although the cellular components of the tendon were damaged and the antigenicity of the tendon was lowered, it did not necessarily mean that homologous tendon graft would always be successful in transplantation.
【Abstract】ObjectiveTo discuss the molecular structures and functions of Alu repeats,and its relationships with malignant tumors. MethodsAdvances in molecular biology and oncology of Alu repeats in recent years had been reviewed. ResultsHomologous recombination between Alu repeats may result in various genetic exchanges,including duplications, deletions and translocations,cause a series of malignancy alteration by activating some oncogenes. ConclusionAlu repeats as a sort of multifunction regulatory sequences may play an important role during the carcinogenesis and progression of some tumors.