Tissue Injury and Cellular Immune Responses to Cadmium Chloride Exposure in the Common Mussel Mytilus edulis: Modulation by Lipopolysaccharide

The immunotoxic effects of cadmium (Cd) exposure in bivalves are poorly understood and whether or not stimulation of the immune system exacerbates Cd toxicity is unclear. The mussel Mytilus edulis was exposed to 20 or 50 μg/l total Cd for up to 11 days compared to no added Cd controls to assess immune and other physiological responses. Selected experiments were then repeated in the presence of a lipopolysaccharide (LPS) challenge with and without subsequent Cd exposure. Immune functions of hemocytes, hematology, hemolymph glucose and ion content, as well as superoxide dismutase (SOD) activity and organ pathology were measured. Cd accumulated mainly in digestive gland and gills and to a lesser extent in the adductor muscle. Exposure to 20 μg/l Cd alone caused a transient modulated of phagocytosis and increased neutral red retention (Kruskal–Wallis, p = 0.002). The higher Cd concentration also increased cytotoxicity, and decreased hemocyte count. Changes in hemolymph Na⁺, K⁺, and glucose were small or negligible. Histopathological examination showed tissue injuries consistent with inflammation and necrosis in the gills, digestive gland, and adductor muscle during Cd exposure alone. LPS injection alone and LPS + Cd caused an increase in the number of circulating hemocytes by the end of the experiment (Kruskal–Wallis, p = 0.01) and a transient rise in phagocytosis at day 4 (analysis of variance (ANOVA), p = 0.001). The LPS + Cd treatment also caused transient changes in neutral red retention and in the cytotoxicity of hemocytes compared to controls. Intracellular SOD activity did not change in hemocytes under any treatment. Tissue inflammation and pathology was greatly increased by the effect of Cd exposure with an LPS injection compared to either treatment alone. We conclude that immunostimulation with LPS can greatly increase Cd-related organ pathologies but does not necessarily alter the responses of hemocytes.     

Cellular Immunity And Malnutrition

Cellular immunity is depressed in infantile malnutrition. Anatomic and functional changes in the lymphoid system play an important part in determining the clinical patterns of infection suffered, by children with protein-calorie malnutrition.     

Cellular transporters for zinc

Nutritionally essential metals such as zinc are moved into and out of cells by a series of transport proteins or transporters. Their tri-fold purpose is to procure zinc from the environment, to protect cells against zinc toxicity, and maintain ample supplies of zinc for metabolic purposes. Two families of zinc transporters are known: the ZIP family that imports zinc and the ZnT family that functions in releasing zinc or sequestering zinc internally.     

端粒与细胞衰老

端粒是现代生物学研究的热点,端粒封闭了染色体的末端并维持了染色体的稳定性,端粒的缺失与细胞的衰老有密切的关系。本文就端粒的结构和功能与细胞老化的关系进行了综述。     

战创伤伤情评估四种评分法比较

目的 对比研究临床上常用的四种不同的创伤评分法,创伤记分、简易战伤记分法、院前指数和CRAMS评分在战伤伤情评估中的相互关系和差异性.方法 分别采用TS、SWS、PHI和CRAMS评分对2014年某军医大学卫勤演练的32名模拟伤员进行伤情评估,用Spearman秩相关分析四种方法的相关性,采用Friedman Test检验进行差异性分析,采用Wilcoxon符号秩检验进行各种评分方法之间的两两比较.结果 四种方法之间有明显相关性,PHI与其他三种评分法均呈负相关,TS、SWS和CRAMS评分呈正相关.Friedman秩和检验表明四种评分方法之间差异有统计学意义.除PHI和CRAMS评分之间没有统计学差异之外,其他任何两种评分之间均有统计学差异.结论 四种评分法均可用于战伤伤情评估,PHI和CRAMS评分评估病情危重程度方面更为接近,但每种评分法各有其局限性,有待于完善.