Elucidation of mitochondrial effects by tetrahydroaminoacridine (tacrine) in rat, dog, monkey and human hepatic parenchymal cells

Tetrahydroaminoacridine (tacrine) causes morphological and functional changes in the endoplasmic reticulum, ribosomes, and mitochondria in the liver of humans and animals. In order to investigate species differences as well as to understand the morphological changes, we examined the effects of tacrine on respiration and electron transport in mitochondria isolated from rat, dog, monkey, and human liver. Tacrine produced significantly decreased respiratory control ratios (RCR) in all species at concentrations ranging from 5 to 25 microg/ml. Human mitochondria were more sensitive to tacrine effects with RCR decreased 24% at 5 microg/ml while other species were unaffected at this concentration. The tacrine effects were characterized by increased hepatic mitochondrial State 4 respiration in rats and decreased State 3 respiration in humans. Mitochondria from aged rats were more sensitive to the effects of tacrine than mitochondria from young animals, with significantly decreased RCR at 10 microg/ml in aged rats while mitochondria from young rats were unaffected at this concentration. Concomitant with the respiratory changes, mitochondrial DNA synthesis was impaired. Since tacrine undergoes extensive biotransformation, we also explored the possibility that metabolites could exert detrimental effects. The ranking order of potency for decreasing RCR caused by monohydroxylated metabolites was: tacrine > 4-OH and 7-OH > 2-OH, 1-OH, and velnacrine with the latter group of metabolites having no effect on mitochondrial respiration at concentrations up to 50 microg/ml. In vivo administration of 20 mg/kg tacrine to rats for up to 20 days caused a paradoxical increase in RCR and P/O on Day 1 and decreased RCR on Days 9 and 20, the later findings being consistent with in vitro data. From these data we propose that tacrine does not necessarily have to be metabolized to exert effects on mitochondria at different sites in the electron transport chain that differ among species. These effects are exacerbated in mitochondria from older animals and humans appear to be more sensitive than the laboratory animals studied.     

Lingual ischemia following tongue entrapment in a glass bottle

A 10-year-old, previously healthy female presented to the emergency department via emergency medical service transport, with her tongue tightly entrapped inside a glass bottle (9 oz, Yoohoo brand of chocolate drink). The tongue was massively edematous and ecchymotic due to impaired venous return from constriction by the neck of the bottle. After repeated attempts at mechanically reducing the tongue out of the bottle, a professional glazier was contacted, who was able to remove the bottle in the operating room with a steel glass cutter. Needle evacuation of a small hematoma was then performed to decrease the pressure ischemia to the tongue, which began to improve quickly.     

Percutaneous transjejunal biliary intervention: 10-year experience with access via Roux-en-Y loops

Ancylostoma duodenale is still the dominant hookworm species in the Mediterranean area, India, China and Japan. In the present study, biopsied materials were taken from the small intestine of 30 patients infected only with A. duodenale and 12 cross matched controls. The results showed some pathological changes in severely infected cases. However, normal or insignificant changes were seen in the enzymatic activity of the intestinal mucosa.     

端点安全面临重重危机 如何轻松应对

正事实上,绝大多数攻击者是经由用户及其设备进入企业的。现实情况往往是黑客跟踪一个用户,然后此用户成为帮助黑客到达数据库或用户凭据的一个管道。因此,企业不仅需要端点安全和网络安全,而且还要将不同的安全方案集成起来。安全厂商也应当听从时代的召唤,建设针对新威胁的安全方案,迎接深度安全的新时代。     

Global Intrinsic Symmetries of Shapes

Although considerable attention in recent years has been given to the problem of symmetry detection in general shapes, few methods have been developed that aim to detect and quantify the intrinsic symmetry of a shape rather than its extrinsic, or pose‐dependent symmetry. In this paper, we present a novel approach for efficiently computing symmetries of a shape which are invariant up to isometry preserving transformations. We show that the intrinsic symmetries of a shape are transformed into the Euclidean symmetries in the signature space defined by the eigenfunctions of the Laplace‐Beltrami operator. Based on this observation, we devise an algorithm which detects and computes the isometric mappings from the shape onto itself. We show that our approach is both computationally efficient and robust with respect to small non‐isometric deformations, even if they include topological changes.     

Sublethal concentrations of mercury in river otters: monitoring environmental contamination

Hair, muscle, and liver mercury concentrations were determined in river otter (Lutra canadensis) carcasses collected from the lower coastal plain and piedmont of Georgia. Mean muscle and hair mercury concentrations were greater (P < 0.001) in otters from the lower coastal plain (4.42 and 24.25 mg/kg wet wt, respectively) compared to otters from the piedmont (1.48 and 15.24 mg/kg, respectively). Liver tissue from lower coastal plain otters averaged 7.53 mg/kg mercury. Mean fetus brain and muscle mercury concentrations were 1.03 and 1.58 mg/kg wet wt, respectively, and fetal muscle mercury concentrations were correlated (r = 0.92) with maternal muscle mercury concentrations. Comparison of mercury concentrations found in Georgia otters to those associated with adverse effects in otter and mink (Mustela vison), indicate sublethal contamination with concentrations in some individuals approaching that observed in experimentally dosed individuals that developed clinical signs of mercurialism. Mercury concentrations in fish from the lower coastal plain approached or exceeded concentrations demonstrated to be toxic to experimentally dosed otters.