The significance of copper chelators in clinical and experimental application

The essentiality and redox-activity of copper make it indispensable in the mammalian system. However, a comprehensive understanding of copper metabolism and function has not been achieved. Copper chelators have been used as an approach to provide insights into copper acquisition, distribution, and disposition at both the cellular and organism level. Unfortunately, the understanding of effective copper chelators is predominantly based upon their chemical structures and their reactions with copper. The understanding of the efficacy of copper chelators in the biological system has been equivocal, thereby leading to under- or misleading-utilization of these agents in clinical and experimental approaches. Current use of copper chelators in vivo almost exclusively either limits the availability or focuses on the removal of copper in mammalian organ system. There are at least two aspects of copper chelators that are yet to be explored. First, copper chelators preferentially bind either cuprous or cupric. As a result, they potentially modulate copper redox-activity without removing copper from the system. Second, copper chelators are characterized as either membrane-permeable or -impermeable, thus would serve as an organ-selective copper delivery or deprivation system to manipulate the biological function of copper. Here we review clinically relevant copper chelators that have been experimentally or clinically studied for their role in manipulation of copper metabolism and function, paying critical attention to potentially more valuable usage of these agents.     

Wolbachia infection and incompatibility dynamics in experimental selection lines

High and low levels of Wolbachia-induced cytoplasmic incompatibility (CI) were selected for in the parasitic wasp Nasonia vitripennis, in the single-infected strain Ti277. After nine generations of selection, males from lines selected for high incompatibility level (HI lines) were significantly more incompatible with uninfected females (AsymC) than the maternal strain. The reverse response, a full compatibility with AsymC, was observed in eight out of 12 lines selected for low incompatibility (LO lines), correlated with loss of Wolbachia infection. Bacterial density estimates in the eggs of some HI lines increased significantly. The procedure for line maintenance resulted in introgression of AsymC nuclear genome into the Ti277 background. Significant changes of CI level and bacterial density due to the introgression were also observed in the control lines, possibly reflecting an effect of host genotype on bacterial density and CI. After selection had been relaxed for six generations, bacterial density in the five high-infected HI lines declined back to a level comparable to the other lines. The data are consistent with the ‘bacterial dosage’ model, but with an upper threshold of bacterial infection above which there is no correlation between infection level and CI level. We further investigate the maternal transmission of bacterial density by a mother–daughter regression on bacterial density. The pattern observed is consistent with a density dependent regulation of bacterial numbers around an ‘equilibrium’ density, independent of any effects of CI. The equilibrium value is likely to be determined by both bacterial strain and host genotype.     

植物功能型及其生态学意义

植物功能型是近年来在全球变化研究中引入的一个新的生态学术语,综 植物功能型概念的由来、划分植物及其生态学意义,用系统生物学的理论与方法理解植物功能型,并指出了植物功能型在全球变化研究中的意义。     

Phenomenon of DNA-abzyme cross-reactivity and its significance for the mechanisms of cytotoxicity and apoptosis

The physiological role of DNA-abzymes and their involvement in pathogenesis of different autoimmune disorders is still unknown. At the same time, a variety of properties and features of DNA-hydrolyzing autoantibodies have been studied. Here, the phenomenon of the cross-reactivity of DNA-abzymes with the nuclear matrix proteins was studied. The possible value of the phenomenon for the cytotoxic activity of DNA-hydrolyzing autoantibodies was debated as well. A new hypothesis is put forward regarding the DNA-abzymes formation based on the phenomenon of the cross-reactivity of polyclonal DNA-abzymes with nuclear matrix proteins free of native DNA. Preliminary results suggest that there are mechanisms of cytotoxicity mediated by DNA-abzymes and independent from the system of complement and cytotoxic T-lymphocytes.     

Anatomy of the buccal fat pad and its clinical significance

Interest in the anatomy of the buccal fat pad was aroused by two clinical cases where the fat pad was involved by pathology. In one, there was an extensive lipoma of the buccal fat pad which had been unsuccessfully operated on on two previous occasions. The reason for the lack of success was incomplete removal of the fat pad. In the second case, there was an arteriovenous malformation involving the fat pad which necessitated complete removal. Fresh cadaver dissections were carried out to accurately determine the anatomy. Particular attention was paid to the temporal extension, since this area is frequently disregarded.