Modified reversed-phase high performance liquid chromatography for the determination of leukotriene B_4 and 5-hydroxyeicosatetraenoic acid in peripheral neutrophils of rabbits

Modification was made on the reversed-phase high performance liquidchromatography（RP-HPLC）with Yue et al’s method as a base.The modified RP-HPLCwas used to detect leukotriene B4（LTB4）and 5-hydroxyeicosatetraenoic acid（5-HETE）.Itwas found that the modified method has the merits of simpler procedures,shortertesting time and more satisfactory efficacy.

Effects of tetrandrine on the changes of free calcium level in neutrophils after smoke inhalation injury in the rabbit

The changes of the cytoplasmic free calcium level in the neutrophils after smoke in-halation injury were observed in rabbits and then the effects of tetrandrine,a calcium antago-nist,on the changes of free calcium level were studied.It was found that the number of neu-trophils increased significantly preceded by a transient decrease in the blood and also increasedin the bronehoalveolar lavage fluid after smoke inhalation.and the level of cytoplasmic free calci-um in the blood neutrophil increased likewise.Administration of tetrandrine resulted in a reduc-tion of the neutrophils number in the lungs and the free calcium level in the blood neutrophils toalleviate the pulmonary injury due to smoke inhalation.It is believed that there is a close rela-tionship between the activation of neutrophils and the pathophysiological changes of the lungs,and tetrandrine can exert its therapeutic effects on the injury by decreasing the free calcium levelin the neutrophils to modulate their functions.

Transplantation tolerance mediated by regulatory T cells in mice

Background With potent suppressive effect on responder T cells, CD 4 +CD 25 + regulatory T (Treg) cells have become the focus of attention only recently and they may play an important role in transplantation tolerance However, the mechanism of action is not clear This study was designed to assess the possibility of using CD 4 +CD 25 + Treg cells to induce transplantation tolerance and to investigate their mechanism of action KH*2/5DMethods CD 4 +CD 25 + Treg cells were isolated using magnetic cell separation techniques Mixed lymphocyte reactions were used to assess the ability of Treg cells to suppress effector T cells Before skin transplantation, various numbers of CD 4 +CD 25 +Treg cells, which have been induced using complex skin antigens from the donor, were injected into the host mice either intraperitoneally (0 5×10 5, 1×10 5, 2×10 5, 3×10 5, 4×10 5, or 5×10 5) or by injection through the tail vein (5×10 3, 1×10 4, 2×10 4, 5×10 4, 1×10 5, 2×10 5) Skin grafts from two different donor types were used to assess whether the induced Treg cells were antigen-specific The survival time of the allografts were observed Single photon emission computed tomography was also used to determine the distribution of Treg cells before and after transplantation Results Treg cells have suppressive effect on mixed lymphocyte reactions Grafts survived longer in mice receiving CD 4 +CD 25 + Treg cell injections than in control mice There was a significant difference between groups receiving intraperitoneal injection of either 2×10 5 or 3×10 5 CD 4 +CD 25 +Treg cells and the control group ( P <0 05, respectively) Better results were achieved when Treg cells were injected via the tail vein than when injected intraperitoneally The transplantation tolerance induced by CD 4 +CD 25 + Treg cells was donor-specific Analysis of the localization of Treg cells revealed that Treg cells mainly migrated from the liver to the allografts and the spleen KH*2/5DConclusions CD 4 +CD 25 +Treg cells can induce donor-specific transplantation tolerance Cell-to-cell contact may be the primary mechanism by which Treg cells act on effector T cells

Polymyxin B antagonizing biological activity of lipopolysaccharide

Objective:To investigate the mechanism of polymyxin B(PMB)antagonizing the biological activity of lipopolysaccharide(LPS). Methods:The affinity of PMB for LPS and lipid A was assayed by biosensor,and the neutralization of PMB for LPS(2 ng/ml)was detected by kinetic turbidimetric limulus test.The releases of TNF-αand IL-6 in murine peritoneal macrophages(PM(?)) after exposure to LPS(100 ng/ml)were detected,and the expression levels of TLR4, TNF-αand IL-6 mRNA in PM(?) induced by LPS(100 ng/ml)were measured by RT-PCR. Results:PMB had high-affinity to LPS and lipid A with dissociation equilibrium constants of 18.9 nmol/L and 11.1 nmol/L,respectively,and neutralized LPS in a dose- dependent manner.Furthermore,PMB could markedly inhibit the expressions of TLR4,TNF-αand IL-6 mRNA and the release of cycokines in LPS-stimulated murine PM(?). Conclusions:PMB neutralizes LPS and inhibites the expression and release of cycokines in macrophages,in which the affinity of PMB for lipid A plays an important role.