Areca nut extracts-activated secretion of leukotriene B4, and phosphorylation of p38 mitogen-activated protein kinase and elevated intracellular calcium concentrations in human polymorphonuclear leukocytes.

BACKGROUND AND OBJECTIVE: Polymorphonuclear leukocytes are the major source of leukotriene B4, which is synthesized via the 5-lipoxygenase pathway. Activation of the 5-lipoxygenase pathway is regulated by intracellular calcium and the phosphorylation of p38 mitogen-activated protein kinase (MAPK). The impact of areca nut extracts on the biosynthesis of leukotriene B4 by human polymorphonuclear leukocytes was evaluated, and some of the possible mechanisms underlying the responses were examined. MATERIAL AND METHODS: Polymorphonuclear leukocytes were treated with various concentrations of areca nut extracts. The concentrations of leukotriene B4 released into the supernatants were evaluated using enzyme immunoassay. The phosphorylation of p38 MAPK was monitored using immunoblotting, and the cytosolic calcium kinetics were assessed fluorometrically using Fura-2. RESULTS: Exposure of polymorphonuclear leukocytes to areca nut extracts led to a dose-dependent increase in the production of leukotriene B4, with levels peaking at 30 min and decreasing thereafter. Areca nut extracts enhanced the phosphorylation of p38 MAPK, an enzyme known to activate 5-lipoxygenase. Incubation with areca nut extracts also resulted in a rapid elevation of intracellular calcium concentrations in polymorphonuclear leukocytes. The induction of leukotriene B4 by areca nut extracts was suppressed with the p38 MAPK inhibitor, SB203580, or with the intracellular calcium chelator, BAPTA-AM. CONCLUSION: The interaction of areca nut extracts with polymorphonuclear leukocytes activated the arachidonic acid metabolic cascade. Incubation of polymorphonuclear leukocytes with areca nut extracts resulted in the activation of intracellular events, such as phosphorylation of p38 MAPK and Ca2+ mobilization, involved in the release of pro-inflammatory lipid mediators. The results of this study emphasize the potential importance of polymorphonuclear leukocytes as a source of leukotriene B4, which may modulate the inflammatory response in areca chewers.

Investigation of rice transgene flow in compass sectors by using male sterile line as a pollen detector.

Rice is the most important staple food in the world. The rapid development of transgenic rice and its future commercialization have raised concerns regarding transgene flow and its potential environmental risk. It is known that rice is a self-pollinated crop; the outcrossing rate between common cultivars is generally less than 1%. In order to improve the detection sensitivity of rice transgene flow, a male sterile (ms) line BoA with a high outcrossing rate was used as a pollen detector in this study. A concentric circle design was adopted, in which the transgenic rice B2 containing bar gene as a pollen donor was planted in the center circle and the recipient BoA was planted in eight compass sectors. The frequency of transgene flow in compass sectors was analyzed by continuous sampling to generate cumulative data. The results of two years with sound reproducibility demonstrated that the rice gene flow was closely associated with the wind direction. According to the mean frequency of transgene flow, the eight sectors can be divided into two groups: a higher frequency group downstream of the prevailing wind (DPW) with a mean frequency ranging from 6.47 to 26.24%, and a lower frequency group lateral to or upstream of the prevailing wind (UPW) with a mean frequency of 0.39 to 3.03%. On the basis of the cumulative data, 90-96% of the cumulative gene flow events occurred in the four DPW sectors, while it was 4-10% in the four UPW sectors. By using these systematic data, simulation models and isograms of transgene flow in the eight compass sectors were calculated and drawn, respectively.

Relationship between acupuncture-induced immunity and the regulation of central neurotransmitters in the rabbit: VI. The influence of NDR stimulation on acupuncture regulation of immune function in rabbit.

T-lymphocyte transformation ability decreased and the function of the B-lymphocyte and mononuclear leucocyte/macrophage system increased when the activity of central serotonergic neurons was enhanced by the stimulation of nucleus dorsal raphe (NDR). These changes induced by NDR stimulation were not effected by electroacupuncture (EA) when EA was performed on the background of NDR stimulation. By comparing these results with the previous resultant that immunoreactions were affected by locus coeruleus (LC) stimulation and LC stimulation plus EA, some regularity had been discovered. So, a hypothesis was put forward by us that the catecholaminergic system plays a main role in EA regulation of cellular immunity while the serotonergic system plays such a role in EA regulation of humoral immunity.

Relationship between acupuncture-induced immunity and the regulation of central neurotransmitters in the rabbit: I. Effect of central catecholaminergic neurons in regulating acupuncture-induced immune function.

The central catecholaminergic neurons play an important role in the promotion of the T-lymphocyte transformation and the regulation of the positive rate of acid a-naphthylacetate esterase (ANAE) activity with acupuncture. The mechanism by which acupuncture promotes the T-lymphocyte transformation function may be principally by promoting the anabolism of the T-lymphocyte and speeding up the anabolism of the DNA. Judging from the fact that acupuncture increases the positive rate of ANAE, it can be assumed that the quantity of T-lymphocyte was increased markedly. It remains to be clarified what links exist through which the central catecholaminergic neurons can influence the acupuncture induced immunity, and what the effect of other transmitter neurons of the central nervous system are on acupuncture induced immunity.