低强度微波辐射对人精子非热生物效应的研究

选用频率２４５０ＭＨｚ分别在３、５、７、９ｍＷ／ｃｍ２的功率密度,使用新型宽带横电磁传输室（ＢＴＥＭＣＥＬＬ）辐射人精子１小时,我们发现只有５ｍＷ／ｃｍ２的强度对人射子的活动度、存活率、畸形率又穿卵率有显著的影响,这表明在５ｍＷ／ｃｍ２附近存在明显的功率密度窗效应。同时还发现,７ｍＷ／ｃｍ２组的精子的染色体出现畸变。最后对实验结果进行了讨论。     

Experimental study and mechanism analysis on bioeffects by nanosecond electromagnetic pulses

The athermal bioeffects caused by nanosecond electromagnetic pulses with body cells was studied by using a broad band transverse EM-wave cell (BTEM CELL). The experimental system and preliminary mechanism analysis were presented.     

Influence of cycle exercise on acetone in expired air and skin gas

Abstract

This study investigated the influence of cycle exercise on acetone concentration in expired air and skin gas. The subjects for this experiment were eight healthy males. Subjects performed a continuous graded exercise test on a cycle ergometer. The workloads were 360 (1.0 kg), 720 (2.0 kg), 990 (2.75 kg) kgm/min, and each stage was 5 min in duration. A pedaling frequency of 60 rpm was maintained. Acetone concentration was analyzed by gas chromatography. The acetone concentration in expired air and skin gas during exercise at 990 kgm/min intensity was significantly increased compared with the basal level. The skin-gas acetone concentration at 990 kgm/min significantly increased compared with the 360 kgm/min (P < 0.05). The acetone excretion of expired air at 720 kgm/min and 990 kgm/min significantly increased compared with the basal level (P < 0.05). Acetone concentration in expired air was 4-fold greater than skin gas at rest and 3-fold greater during exercise (P < 0.01). Skin gas acetone concentration significantly related with expired air (r = 0.752; P < 0.01). This study confirmed that the skin-gas acetone concentration reflected that of expired air.     

The mechanism underlying the effects of the cell surface ATP synthase on the regulation of intracellular acidification during acidosis

The F1F0 ATP synthase has recently become the focus of anti‐cancer research. It was once thought that ATP synthases were located strictly on the inner mitochondrial membrane; however, in 1994, it was found that some ATP synthases localized to the cell surface. The cell surface ATP synthases are involved in angiogenesis, lipoprotein metabolism, innate immunity, hypertension, the regulation of food intake, and other processes. Inhibitors of this synthase have been reported to be cytotoxic and to induce intracellular acidification. However, the mechanisms by which these effects are mediated and the molecular pathways that are involved remain unclear. In this study, we aimed to determine whether the inhibition of cell proliferation and the induction of cell apoptosis that are induced by inhibitors of the cell surface ATP synthase are associated with intracellular acidification and to investigate the mechanism that underlines the effects of this inhibition, particularly in an acidic tumor environment. We demonstrated that intracellular acidification contributes to the cell proliferation inhibition that is mediated by cell surface ATP synthase inhibitors, but not to the induction of apoptosis. Intracellular acidification is only one of the mechanisms of ecto‐ATP synthase‐targeted antitumor drugs. We propose that intracellular acidification in combination with the inhibition of cell surface ATP generation induce cell apoptosis after cell surface ATP synthase blocked by its inhibitors. A better understanding of the mechanisms activated by ecto‐ATP synthase‐targeted cancer therapies may facilitate the development of potent anti‐tumor therapies, which target this enzyme and do not exhibit clinical limitations. J. Cell. Biochem. 114: 1695–1703, 2013. © 2013 Wiley Periodicals, Inc.     

Cadmium affects focal adhesion kinase (FAK) in mesangial cells: Involvement of CaMK‐II and the actin cytoskeleton

The toxic metal ion cadmium (Cd²⁺) induces pleiotropic effects on cell death and survival, in part through effects on cell signaling mechanisms and cytoskeletal dynamics. Linking these phenomena appears to be calmodulin‐dependent activation of the Ca²⁺/calmodulin‐dependent protein kinase II (CaMK‐II). Here we show that interference with the dynamics of the filamentous actin cytoskeleton, either by stabilization or destabilization, results in disruption of focal adhesions at the ends of organized actin structures, and in particular the loss of vinculin and focal adhesion kinase (FAK) from the contacts is a result. Low‐level exposure of renal mesangial cells to CdCl₂ disrupts the actin cytoskeleton and recapitulates the effects of manipulation of cytoskeletal dynamics with biological agents. Specifically, Cd²⁺ treatment causes loss of vinculin and FAK from focal contacts, concomitant with cytoskeletal disruption, and preservation of cytoskeletal integrity with either a calmodulin antagonist or a CaMK‐II inhibitor abrogates these effects of Cd²⁺. Notably, inhibition of CaMK‐II decreases the migration of FAK‐phosphoTyr925 to a membrane‐associated compartment where it is otherwise sequestered from focal adhesions in a Cd²⁺‐dependent manner. These results add further insight into the mechanism of the CaMK‐II‐dependent effects of Cd²⁺ on cellular function. J. Cell. Biochem. 114: 1832–1842, 2013. © 2013 Wiley Periodicals, Inc.     

Evidence for ACD5 ceramide kinase activity involvement in Arabidopsis response to cold stress

Although sphingolipids emerged as important signals for plant response to low temperature, investigations have been limited so far to the function of long‐chain base intermediates. The formation and function of ceramide phosphates (Cer‐Ps) in chilled Arabidopsis were explored. Cer‐Ps were analysed by thin layer chromatography (TLC) following in vivo metabolic radiolabelling. Ceramide kinase activity, gene expression and growth phenotype were determined in unstressed and cold‐stressed wild type (WT) and Arabidopsis ceramide kinase mutant acd5. A rapid and transient formation of Cer‐P occurs in cold‐stressed WT Arabidopsis plantlets and cultured cells, which is strongly impaired in acd5 mutant. Although concomitant, Cer‐P formation is independent of long‐chain base phosphate (LCB‐P) formation. No variation of ceramide kinase activity was measured in vitro in WT plantlets upon cold stress but the activity in acd5 mutant was further reduced by cold stress. At the seedling stage, acd5 response to cold was similar to that of WT. Nevertheless, acd5 seed germination was hypersensitive to cold and abscisic acid (ABA), and ABA‐dependent gene expression was modified in acd5 seeds when germinated at low temperature. Our data involve for the first time Cer‐P and ACD5 in low temperature response and further underline the complexity of sphingolipid signalling operating during cold stress.