Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

This article summarizes the available evidence on the efficacy of gangliosides to reduce the degree of reactive oxygen species (ROS)-mediated damage. The antioxidative efficacy of exogenous gangliosides in protecting different cells encouraged us to examine their ability to protect human spermatozoa. Gangliosides are sialic acid-containing glycosphingolipids with strong amphiphilic character due to the bulky headgroup made of several sugar rings with sialic acid residues and the double-tailed hydrophobic lipid moiety. The amphiphilicity of gangliosides allows them to exist as micelles in aqueous media when they are present at a concentration above their critical micellar concentration. The protective effect of ganglioside micelles on spermatozoa is believed to stem from their ability to scavenge free radicals and prevent their damaging effects. In our study, we particularly focused our attention on the protective effect of ganglioside micelles on DNA in human spermatozoa exposed to cryopreservation. The results indicate that ganglioside micelles can modulate the hydrophobic properties of the sperm membrane to increase tolerance to DNA fragmentation, thus protecting the DNA from cryopreservation-induced damage. Further actions of ganglioside micelles, which were documented by biochemical and biophysical studies, included (i) the modulation of superoxide anion generation by increasing the diffusion barrier for membrane events responsible for signal translocation to the interior of the cell; (ii) the inhibition of iron-catalysed hydroxyl radical formation due to the iron chelation potential of gangliosides; and (iii) inhibition of hydrogen peroxide diffusion across the sperm membrane.     

Persistent Behavioural Changes in Rats Following Inescapable Shock Stress: a Potential Model of Posttraumatic Stress Disorder

Behavioural changes in rats two weeks after inescapable shock stress were studied using a shuttle-box task (active avoidance/escape). Rats exposed to inescapable shock stress two weeks beforehand showed more frequent avoidance responses and greater within-group variation in both avoidance response and general activity during the test than rats in a control group. General activity during an unstressful period (before starting the test) did not differ significantly between groups. This relatively prolonged increase in responsiveness to external stimuli in the stressful context may be a useful experimental model of posttraumatic stress disorder, especially in relation to hypervigilance.     

临床护士工作压力源调查分析及对策

目的通过研究临床护士的工作压力源，为探索减轻临床护士压力的方法和途径提供理论依据。方法采用护士压力源量表，利用随机分层抽样的方法，对我院内、外、妇、儿，四大临床科室共102名护士进行调查。结果临床护士在五个维度的压力源中，护理专业及工作方面的得分高于时间分配及工作量、病人护理、管理及人际关系、环境及设备方面，差异具有统计学意义（P〈0．01）。结论针对临床护士最突出的压力源特点，护士自身、医院和社会应采取有效对策，预防或减轻护士工作压力，以促进护士的身心健康及个人综合素质的普遍提升，不断提高护理质量。     

Methuselah‐like genes affect development,stress resistance,lifespan and reproduction in Tribolium castaneum

Methuselah (Mth) is associated with lifespan, stress resistance and reproduction in Drosophila melanogaster, but Mth is not present in nondrosophiline insects. A number of methuselah‐likes (mthls) have been identified in nondrosophiline insects, but it is unknown whether the functions of mth are shared by mthls or are divergent from them. Five mthls have been identified in Tribolium castaneum. Although they have different developmental expression patterns, they all enhance resistance to starvation. Only mthl1 and mthl2 enhance resistance to high temperature, whereas mthl4 and mthl5 negatively regulate oxidative stress in T. castaneum. Unlike in the fly with mth mutation, knockdown of mthls, except mthl3, shortens the lifespan of T. castaneum. Moreover, mthl1 and mthl2 are critical for Tribolium development. mthl1 plays important roles in larval and pupal development and adult eclosion, while mthl2 is required for eclosion. Moreover, mthl1 and mthl2 silencing reduces the fertility of T. castaneum, and mthl1 and mthl4 are also essential for embryo development. In conclusion, mthls have a significant effect on insect development, lifespan, stress resistance and reproduction. These results provide experimental evidence for functional divergence among mthls/mth and clues for the signal transduction of Mthls.     

Acute and subacute pulmonary toxicity and mortality in mice after intratracheal instillation of ZnO nanoparticles in three laboratories

Inhalation is the main pathway of ZnO exposure in the occupational environment but only few studies have addressed toxic effects after pulmonary exposure to ZnO nanoparticles (NP). Here we present results from three studies of pulmonary exposure and toxicity of ZnO NP in mice. The studies were prematurely terminated because interim results unexpectedly showed severe pulmonary toxicity. High bolus doses of ZnO NP (25 up to 100 μg; ≥1.4 mg/kg) were clearly associated with a dose dependent mortality in the mice. Lower doses (≥6 μg; ≥0.3 mg/kg) elicited acute toxicity in terms of reduced weight gain, desquamation of epithelial cells with concomitantly increased barrier permeability of the alveolar/blood as well as DNA damage. Oxidative stress was shown via a strong increase in lipid peroxidation and reduced glutathione in the pulmonary tissue. Two months post-exposure revealed no obvious toxicity for 12.5 and 25 μg on a range of parameters. However, mice that survived a high dose (50 μg; 2.7 mg/kg) had an increased pulmonary collagen accumulation (fibrosis) at a similar level as a high bolus dose of crystalline silica. The recovery from these toxicological effects appeared dose-dependent. The results indicate that alveolar deposition of ZnO NP may cause significant adverse health effects.     

High Dietary Fat Intake during Lactation Promotes the Development of Social Stress-Induced Obesity in the Offspring of Mice

This study examined how a maternal high-fat diet (HD) during lactation and exposure of offspring to isolation stress influence the susceptibility of offspring to the development of obesity. C57BL/6J mice were fed a commercial diet (CD) during pregnancy and a CD or HD during lactation. Male offspring were weaned at three weeks of age, fed a CD until seven weeks of age, and fed a CD or HD until 11 weeks of age. Offspring were housed alone (isolation stress) or at six per cage (ordinary circumstances). Thus, offspring were assigned to one of eight groups: dams fed a CD or HD during lactation and offspring fed a CD or HD and housed under ordinary circumstances or isolation stress. Serum corticosterone level was significantly elevated by isolation stress. High-fat feeding of offspring reduced their serum corticosterone level, which was significantly elevated by a maternal HD. A maternal HD and isolation stress had combined effects in elevating the serum corticosterone level. These findings suggest that a maternal HD during lactation enhances the stress sensitivity of offspring. White adipose tissue weights were significantly increased by a maternal HD and isolation stress and by their combination. In addition, significant adipocyte hypertrophy was induced by a maternal HD and isolation stress and exacerbated by their combination. Thus, a maternal HD and isolation stress promote visceral fat accumulation and adipocyte hypertrophy, accelerating the progression of obesity through their combined effects. The mechanism may involve enhanced fatty acid synthesis and lipid influx from blood into adipose tissue. These findings demonstrate that a maternal HD during lactation may increase the susceptibility of offspring to the development of stress-induced obesity.     

创伤后应激障碍合并酒精使用障碍的访谈与治疗

本文目的是通过报道病例诊疗全过程,呈现创伤后应激障碍(PTSD)合并酒精使用障碍的临床诊疗思路及治疗方案。咨客,男性,55岁。12岁时目睹母亲自杀的全过程,随后出现恐惧、孤独、失眠、回避谈论创伤相关话题、反复出现与创伤相关的梦境、易激惹、疼痛及酗酒等一系列情绪、认知、躯体及行为改变,并持续至今。社会功能明显受损,近1年和妻子离婚后症状加重而前来咨询。经过本次咨询,被诊断为PTSD合并酒精使用障碍。建议采用生物-心理-社会的综合干预方法,鼓励咨客进行规律运动,使用选择性5-羟色胺和去甲肾上腺素再摄取抑制剂(SNRI)及第二代抗精神病药物改善情绪、缓解疼痛;心理治疗方面,推荐延迟暴露疗法和认知调整;社会资源方面,在症状缓解后,鼓励咨客积极寻找工作,创造挽回其前妻的可能性。