Red cell antioxidant enzymes and prognostic indexes in patients with burns

Red cell superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) were measured in 66 burned patients (57 men, 9 women, age 16–78 years). BSAB varied from 15 to 93% and ABSI from 3 to 14 points. In the first week after injury the activity of SOD was significantly decreased as compared with the activity of the enzymes in the control group and was also below the reference values. Later the activity of SOD increased up to the normal range. The activity of CAT followed a similar pattern but the differences were not significant. No significant changes in red cell GPX were found during the monitored period. We did not find any significant association between the antioxidant enzyme activities and the markers of burns severity. On the other side there was a significant indirect association between the change of SOD activity (calculated as a difference between the first week values after the injury and the activities measured later) and BSAB.     

香丹注射液联合左卡尼汀治疗急性病毒性心肌炎的临床研究

目的探讨香丹注射液联合左卡尼汀治疗急性病毒性心肌炎的临床效果。方法选取2014年2月—2017年2月上海市静安区闸北中心医院收治的急性病毒性心肌炎患者80例,随机分为对照组(40例)和治疗组(40例)。对照组静脉滴注左卡尼汀注射液,100 mg/kg加入5%葡萄糖溶液100 mL,1次/d。治疗组在对照组基础上静脉滴注香丹注射液,0.5 mL/kg加入5%葡萄糖溶液100 mL,最大剂量15 mL/d,1次/d。两组均连续治疗14 d。观察两组患者临床疗效,同时比较治疗前后两组患者症状改善时间、心肌酶谱、心功能指标、氧化应激指标、免疫球蛋白和淋巴细胞水平。结果治疗后,对照组和治疗组临床有效率分别为77.5%、95.0%,两组比较差异具有统计学意义(P0.05)。治疗后,治疗组患者胸闷、头晕、肢冷、烦躁等症状改善时间比对照组显著缩短(P0.05)。治疗后,两组血清天门冬氨酸氨基转移酶(AST)、磷酸肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)水平均显著下降(P0.05),左室射血分数(LVEF)、每搏输出量(SV)显著升高(P0.05),且治疗后治疗组心肌酶谱和心功能指标改善明显优于对照组(P0.05)。治疗后,两组血清超氧化物歧化酶(SOD)、谷胱甘肽(GSH)水平均显著升高(P0.05),血清丙二醛(MDA)水平均显著降低(P0.05),且治疗后治疗组比对照组改善更明显(P0.05)。治疗后,两组血清IgA、IgG水平均显著上升(P0.05),外周血Th17细胞百分率、Th17/Treg比率均显著减小(P0.05),且治疗后治疗组比对照组改善更明显(P0.05)。结论香丹注射液联合左卡尼汀治疗急性病毒性心肌炎更能有效缓解患者症状,改善心功能,调控机体氧化应激状态,增强免疫功能。     

The immunological benefit of higher dose N-acetyl cysteine following mechanical ventilation in critically ill patients

Background

Sepsis complication is a major cause of death in multiple trauma critically ill patients. Defensin (cysteine rich anti-microbial peptides), as an important component of immune system, might play an important role in this process. There is also rising data on immunological effects of N-acetyl-cysteine (NAC), a commonly used anti-oxidant in oxidative stress conditions and glutathione (GSH) deficiencies. The aim of the present study was to evaluate the potential beneficial effects of NAC administration on multiple trauma patients with sepsis.

Methods

In a prospective, randomized controlled study, 44 multiple trauma critically ill patients who were mechanically ventilated and met the criteria of sepsis and admitted to the intensive care unit (ICU) were randomized into two groups . Control group received all standard ICU therapies and NAC group received intravenous NAC 3 gr every 6 hours for 72 hours in addition to standard therapies. Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, length of ICU stay, ICU mortality were recorded. Levels of serum Immunoglobulin M (IgM), Human β-Defensin 2 (HβD2) and GSH were assessed at baseline and 24, 72, 120 hours after intervention.

Results

During a period of 13-month screening, 44 patients underwent randomization but 5 patients had to be excluded. 21 patients in NAC group and 18 patients in control group completed the study. For both groups the length of ICU stay, SOFA score and systemic oxygenation were similar. Mortality rate (40% vs. 22% respectively, p = 0.209) and ventilator days (Mean ± SD 19.82 ± 19.55 days vs. 13.82 ± 11.89 days respectively, p = 0.266) were slightly higher for NAC group. IgM and GSH levels were similar between two groups (p = 0.325, 0.125 respectively), HβD2 levels were higher for NAC group (at day 3).

Conclusion

High dose of NAC administration not only did not improve patients’ outcome, but also raised the risk of inflammation and was associated with increased serum creatinine.     

Isolation,synthesis and characterization of ω-TRTX-Cc1a,a novel tarantula venom peptide that selectively targets L-type CaV channels

Spider venoms are replete with peptidic ion channel modulators, often with novel subtype selectivity, making them a rich source of pharmacological tools and drug leads. In a search for subtype-selective blockers of voltage-gated calcium (Ca_V) channels, we isolated and characterized a novel 39-residue peptide, ω-TRTX-Cc1a (Cc1a), from the venom of the tarantula Citharischius crawshayi (now Pelinobius muticus). Cc1a is 67% identical to the spider toxin ω-TRTX-Hg1a, an inhibitor of Ca_V2.3 channels. We assembled Cc1a using a combination of Boc solid-phase peptide synthesis and native chemical ligation. Oxidative folding yielded two stable, slowly interconverting isomers. Cc1a preferentially inhibited Ba²⁺ currents (I_Ba) mediated by L-type (Ca_V1.2 and Ca_V1.3) Ca_V channels heterologously expressed in Xenopus oocytes, with half-maximal inhibitory concentration (IC₅₀) values of 825 nM and 2.24 μM, respectively. In rat dorsal root ganglion neurons, Cc1a inhibited I_Ba mediated by high voltage-activated Ca_V channels but did not affect low voltage-activated T-type Ca_V channels. Cc1a exhibited weak activity at Na_V1.5 and Na_V1.7 voltage-gated sodium (Na_V) channels stably expressed in mammalian HEK or CHO cells, respectively. Experiments with modified Cc1a peptides, truncated at the N-terminus (ΔG1–E5) or C-terminus (ΔW35–V39), demonstrated that the N- and C-termini are important for voltage-gated ion channel modulation. We conclude that Cc1a represents a novel pharmacological tool for probing the structure and function of L-type Ca_V channels.     

A tamoxifen derivative,N,N-diethyl-2-[4-(phenylmethyl) phenoxy] ethanamine,selectively targets P-glycoprotein-positive multidrug resistant Chinese hamster cells

DPPE, a tamoxifen derivative with antihistamine activity, was previously shown to potentiate the toxicity of chemotherapeutic drugs. Recently, a Phase III clinical study using doxorubicin with DPPE demonstrated significant increase in the overall survival of breast cancer patients. In this study we examined the effects of DPPE alone on the growth of drug sensitive and P-gp positive CHO cell line. Our results demonstrate DPPE is selectively toxic to P-gp positive cells and the sensitivity to DPPE alone correlated with the levels of P-gp expression. Moreover, in MDR cells, DPPE-induced apoptosis was significantly reduced with Bcl2 overexpression and in the presence of P-gp ATPase inhibitor, PSC833. Furthermore, knockdown of P-gp expression in MDR cells with P-gp-siRNA reversed DPPE sensitivity and increased their sensitivity to doxorubicin and taxol but not to cisplatin. The addition of DPPE to membrane fractions led to dose-dependent increase in P-gp ATPase that was inhibited with PSC833. Moreover, incubation of P-gp positive cells with DPPE led to a significant increase in superoxide levels and a drop in cellular ATP and GSH pools that were reversible with inhibitors of P-gp ATPase. The combined presence of DPPE and the mitochondria electron transport complex III inhibitor, antimycin A, synergized in their effects on the growth of MDR cells but had no effect on the growth of parental drug sensitive cells. Collectively, the results of this study provide a possible mechanism that may be relevant to the clinical results of DPPE in breast cancer trial and demonstrates DPPE as P-gp collateral sensitivity drug.     

Disturbance of antioxidant capacity produced by beauvericin in CHO-K1 cells

Glutathione (GSH) levels, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) as antioxidant defense system were evaluated in CHO-K1 cells after beauvericin (BEA) exposure. The effect of N-acetyl-cysteine (NAC) pre-treatment was assessed. GSH levels significantly decrease 18% and 29% after 5 μM of BEA in fresh medium and NAC pre-treatment, respectively compared to their controls. The GPx activity increased significantly from 35% to 66% in fresh medium and 20% in NAC pre-treatment. GR activity decreased after 5 μM of BEA up to 43% and 53% in fresh medium and NAC pre-treatment, respectively. The GST activity increased in fresh medium (from 61% to 89%) and decreased (from 22% to 35%) after NAC pre-treatment. Comparing BEA exposure in fresh medium and NAC pre-treatment, GSH levels, GPx activity and GST activity increased 716%, 458% and 206%, respectively respect to fresh medium; conversely no changes were observed in GR activity. In addition, NAC is an effective scavenger of BEA. GSH and related enzymes play an antioxidant role in the defense system of CHO-K1 cells exposed to BEA.     

谷胱甘肽对胰岛素淀粉样纤维化的抑制作用

目的探索谷胱甘肽抑制胰岛素淀粉样纤维化及纤维细胞毒性的分子机制。方法在pH 2.0、37℃及90r·min-1震荡的条件下孵育胰岛素,采用硫黄素(ThT)荧光检测胰岛素形成淀粉样纤维的动力学曲线,8-苯胺-1-萘磺酸(ANS)荧光检测胰岛素分子聚集体表面疏水性的变化,透射电镜观察纤维形态,以淀粉样纤维诱导人红细胞的聚集为指标,评估谷胱甘肽对胰岛素纤维细胞毒性的抑制作用。结果胰岛素在本文的实验条件下孵育可形成淀粉样纤维,谷胱甘肽能够抑制胰岛素的淀粉样纤维化和降低形成的纤维聚集体的表面疏水性,并降低胰岛素纤维对细胞的损害作用。谷胱甘肽的这种作用与分子中的巯基相关。结论谷胱甘肽能够抑制胰岛素的淀粉样纤维化,改变胰岛素聚集体的表面特性,从而使聚集体的细胞毒性降低。     

稳恒磁场对小鼠肾脏组织GSH-Px活性及MDA含量的影响

目的　研究稳恒磁场对小鼠肾组织中丙二醛 (MDA)含量及谷胱甘肽过氧化物酶 (GSH Px)活性的影响。方法　采用磁感应强度 (B)为 2 4 6± 4 2mT ,42 0± 2 1mT ,63 5± 3 0mT ,85 1± 2 9mT的稳恒磁场分别作用于小鼠 ,每天平均 4h ,1 5d后处死小鼠检测肾脏组织中MDA的含量及GSH Px活性。结果　B为 2 4 6± 4 2mT ,42 0± 2 1mT ,63 5± 3 0mT ,85 1± 2 9mT磁场暴露的小鼠 ,其肾组织中MDA含量较对照组明显减少 (P <0 0 1 ) ,B为 42 0± 2 1mT ,63 5± 3 0mT的磁场暴露的小鼠 ,其肾组织中GSH Px活性明显增加 (P <0 0 1 ) ,但B为 2 4 6±4 2mT ,85 1± 2 9mT时的GSH Px活性没有明显的变化。结论　提示一定磁感应强度的稳恒磁场对小鼠的肾组织的脂质过氧化代谢产生影响 ,降低了氧化物的生成 ,对延缓衰老有积极作用     

Long-term dietary exposure to low concentration of dichloroacetic acid promoted longevity and attenuated cellular and functional declines in aged Drosophila melanogaster

Dichloroacetic acid (DCA), a water disinfection by-product, has attained emphasis due to its prospect for clinical use against different diseases including cancer along with negative impact on organisms. However, these reports are based on the toxicological as well clinical data using comparatively higher concentrations of DCA without much of environmental relevance. Here, we evaluate cellular as well as organismal effects of DCA at environmentally and mild clinically relevant concentrations (0.02–20.0 μg/ml) using an established model organism, Drosophila melanogaster. Flies were fed on food mixed with test concentrations of DCA for 12–48 h to examine the induction of reactive oxygen species (ROS) generation, oxidative stress (OS), heat shock genes (hsps) and cell death along with organismal responses. We also examined locomotor performance, ROS generation, glutathione (GSH) depletion, expression of GSH-synthesizing genes (gclc and gclm), and hsps at different days (0, 10, 20, 30, 40, 50) of the age in flies after prolonged DCA exposure. We observed mild OS and induction of antioxidant defense system in 20.0 μg/ml DCA-exposed organism after 24 h. After prolonged exposure to DCA, exposed organism exhibited improved survival, elevated expression of hsp27, gclc, and gclm concomitant with lower ROS generation and GSH depletion and improved locomotor performance. Conversely, hsp27 knockdown flies exhibited reversal of the above end points. The study provides evidence for the attenuation of cellular and functional decline in aged Drosophila after prolonged DCA exposure and the effect of hsp27 modulation which further incites studies towards the therapeutic application of DCA.