Stress relaxation of wood partially non-crystallized using aqueous NaOH solutions

Wood samples (Picea jezoensis Carr.) were treated with aqueous NaOH solutions (0-0.20 concentration fraction, 12 conditions), and bending tests were performed to measure stress relaxation. The relationship between mechanical properties and NaOH concentration is discussed. The relaxation modulus and relaxation rate were divided into three concentration ranges. Both decreased slightly for NaOH concentrations less than 0.10, decreased drastically for concentrations between 0.11 and 0.14, and decreased slightly for concentrations greater than 0.15. The change in relaxation behavior upon NaOH treatment was due to an increase in molecular chain mobility in non-crystallized regions along the microfibril longitudinal axis in wood as well as lignin swelling. Furthermore, the molecular chain response in this region required time; thus, the dependence of crystallinity on the relaxation rate was apparent in the long time region.     

Stress, glucocorticoids and glutamate release: effects of antidepressant drugs

Stressful life events impact on memory, cognition and emotional responses, and are known to precipitate mood/anxiety disorders. It is increasingly recognized that stress and its neurochemical and endocrine mediators induce changes in glutamate synapses and circuitry, and this in turn modify mental states. Half a century after the monoamine hypothesis, it is widely accepted that maladaptive changes in excitatory/inhibitory circuitry have a primary role in the pathophysiology of mood/anxiety disorders. The neuroplasticity hypothesis posits that volumetric changes consistently found in limbic and cortical areas of depressed subjects are in good part due to remodeling of neuronal dendritic arbors and loss of synaptic spines. A considerable body of work, carried out with in vivo microdialysis as well as alternative methodologies, has shown that both stress and corticosterone treatment induce enhancement of activity-dependent glutamate release. Accordingly, results from preclinical studies suggest that stress- and glucocorticoid-induced enhancement of glutamate release and transmission plays a main role in the induction of maladaptive cellular effects, in turn responsible for dendritic remodeling.Additional recent work has showed that drugs employed for therapy of mood/anxiety disorders (antidepressants) prevent the enhancement of glutamate release induced by stress. Understanding the action of traditional drugs on glutamate transmission could be of great help in developing drugs that may work directly at this level.     

Long Memory Effects in the Stress Correlation Function

Abstract

The stress correlation function (SCF) in a one-dimensional cellular automata-fluid is calculated by computer simulations upto 3000 time steps. The results are compared with the 1-D tails t ^?1/2 and t ^?2/3 of bare (BMC) and self-consistent (SCMC) mode coupling theories. The crossover between both tails is estimated to occur after t _cross ? 35000 time steps. For t < 400 and systems with L ≥ 500 sites there is good agreement with BMC-theory for finite systems. For t > 400 there are signs of faster-than-1/√t-decay in the SCF. The simulated data for the “divergent” transport coefficient at times t > 400 are analyzed in terms of a crossover function, constructed from SCMC-theory. However a quantitative verification of the SCMC-theory is still out of reach.     

氟比洛芬酯术前预处理对患者术中应激反应的影响

目的：探讨氟比洛芬酯术前预处理对患者术中应激反应的影响。方法：选择我院行全麻下腹式子宫全切术患者60例,随机分为观察组和对照组,每组30例。两组均采用相同的麻醉诱导和维持方案,观察组于手术开始前10min缓慢静注氟比洛芬酯脂微球注射液1mg·Kg。记录诱导前、切皮时、探查时和术毕的平均动脉压和心率;放射免疫分析法测定患者血浆中血浆肾素、血管紧张素Ⅱ、醛固酮、皮质醇的浓度变化。结果：观察组心率、平均动脉压在切皮时、探查时、术毕时均较对照组低,但无显著性差异（p〉0．05）;观察组切皮时、探查时、术毕时血浆肾素、血管肾张素Ⅱ、醛固酮、皮质醇浓度均较对照组低,且差异具有统计学意义（P〈0．05）;两组术中的四种麻药用量均有不同,但差异无统计学意义（P〉0．05）。结论：氟比洛芬酯术前预处理能降低腹式子宫全切术中机体的应激反应,值得推广应用。     

A型行为者应激变量方程的图景

目的：建立A型行为者的应激测量模型方程和应激变量方程与相似性,并作控制分析;方法：A型行为类型问卷得分获得判分尺度,把安静状态与应激状态下测定血浆皮质醇水平的变量以及应激测量模型的应激量和基础量,再经矩阵反演出具体变化方程、并分析稳定性与可控性和能观性;结果：获得一组有生理意义的方程：(1)y=(s-0．839／s 1)X;(2)7．587d^2y／d^2s—(3．068 1．027y)dy／ds-0.1475y=0等,不同时可控性和能观性的特性,心理应激的反馈作用对稳定性有影响;结论：本文初步获得一组应激变量方程,应激反应在心理和生理方面都具有相似性．     

内生真菌对植物生长发育及抗逆性的影响

本文从内生真菌的涵义和基本生物学特征出发,以国内外近二十年来关于内生真菌与植物关系的研究情况作了综述。主要包括内生真菌的检测、鉴定和转染,内生真菌对植物生长发育与抗逆性的影响,以及内生真菌在农业及其他相关领域的应用前景。文中提及作者近期开展的关于内生真菌对黑麦草抗旱性影响的研究课题及其初步进展。     

Role of corticotropin releasing factor in anxiety disorders: a translational research perspective

Anxiety disorders are a group of mental disorders that include generalized anxiety disorder (GAD), panic disorder, phobic disorders (e.g., specific phobias, agoraphobia, social phobia) and posttraumatic stress disorder (PTSD). Anxiety disorders are among the most common of all mental disorders and, when coupled with an awareness of the disability and reduced quality of life they convey, they must be recognized as a serious public health problem. Over 20 years of preclinical studies point to a role for the CRF system in anxiety and stress responses. Clinical studies have supported a model of CRF dysfunction in depression and more recently a potential contribution to specific anxiety disorders (i.e., panic disorder and PTSD). Much work remains in both the clinical and preclinical fields to inform models of CRF function and its contribution to anxiety. First, we will review the current findings of CRF and HPA axis abnormalities in anxiety disorders. Second, we will discuss startle reflex measures as a tool for translational research to determine the role of the CRF system in development and maintenance of clinical anxiety.     

Gender Differences in the Effects of Prenatal Stress on Brain Development and Behaviour

An increased incidence of anxiety, depression and attention deficits in children has been linked to psychological stress during pregnancy. Subjection of a pregnant rat to stress at a time when the foetal limbic and hypothalamic pituitary adrenal (HPA) axes develop results in anxiogenic and depressive behaviour and learning and attention deficits in the offspring, which depend on its gender, intensity and timing of the maternal stress and behaviour being tested. Maternal stress increases corticosterone levels in the foetal brain, decreases foetal testosterone and brain aromatase activity in males, and alters brain catecholamine activity to that in females. Learning deficits, reductions in hippocampal neurogenesis, LTP and dendritic spine density in the prefrontal cortex are more readily seen in prenatally-stressed males, while anxiety, depression and increased response of the HPA axis to stress are more prevalent in females. Genders may differ in the sensitivity of developing brain areas to stress hormones. Special issue dedicated to Dr. Moussa Youdim.     

Changes in pCO<Subscript>2</Subscript>, Symptoms,and Lung Function of Asthma Patients During Capnometry-assisted Breathing Training

In a recent pilot study with asthma patients we demonstrated beneficial outcomes of a breathing training using capnometry biofeedback and paced breathing assistance to increase pCO₂ levels and reduce hyperventilation. Here we explored the time course changes in pCO₂, respiration rate, symptoms and lung function across treatment weeks, in order to determine how long training needs to continue. We analyzed in eight asthma patients whether gains in pCO₂ and reductions in respiration rate achieved in home exercises with paced breathing tapes followed a linear trend across the 4-week treatment period. We also explored the extent to which gains at home were manifest in weekly training sessions in the clinic, in terms of improvement in symptoms and spirometric lung function. The increases in pCO₂ and respiration rate were linear across treatment weeks for home exercises. Similar increases were seen for in-session measurements, together with gradual decreases in symptoms from week to week. Basal lung function remained stable throughout treatment. With our current protocol of paced breathing and capnometry-assisted biofeedback at least 4 weeks are needed to achieve a normalization of pCO₂ levels and reduction in symptoms in asthma patients.     

不同应激因子对小鼠肝脏金属硫蛋白诱导合成的影响

目的筛选出小鼠肝脏金属硫蛋白（MT）合成量最大的诱导方式。方法从时间-效应和剂量-效应两方面研究了重金属元素（Cd）、微量元素（Zn）、重金属与微量元素的组合（Cd＋Zn）、生理因子（饥饿）及创伤因子等五大类组合应激因子、19种诱导方式对小鼠肝脏中MT诱导合成的影响及效果。结果生理因子诱导MT量最小,饥饿诱导小鼠肝脏MT的量随饥饿程度的加重而增加,但各组间差异不显著（P〉0.05）;创伤因子诱导产生MT的量最高,其诱导量随创伤恢复时间的增加而降低,各组之间差异显著（P〈0.01）,本实验诱导峰值（9.0241±0.6441μmol/g）出现在创伤后6 h;重金属元素和微量元素诱导量居中,且两者混合诱导量比单独诱导量之和要大。结论成功筛选出诱导小鼠肝脏MT合成最有效的因子和最佳时间,为进一步大量合成MT及研究其功能等奠定基础。     

外源MeJA对高温胁迫下半夏抗氧化系统和胁迫基因的影响

研究叶面喷施外源MeJA对高温胁迫下半夏的超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性的影响;对脯氨酸(Pro)、丙二醛(MDA)、可溶性糖含量及有效成分含量的影响;对小分子热激蛋白(sHSP)等胁迫相关基因表达的影响。将生长状况一致的半夏植株在40℃高温下进行胁迫处理,实验组喷施50μmol·L^-1的外源MeJA溶液,空白组喷施等量的水,分别在处理2、6、12、24、48 h时进行取样,对样品进行指标测定。结果发现,在40℃高温下,喷施一定浓度的外源MeJA可以提高半夏叶片的SOD、POD、APX活性,降低MDA质量分数,增加脯氨酸及可溶性糖含量;对半夏有机酸含量无明显影响。2个细胞质型小分子热激蛋白和GRRBP蛋白,在MeJA处理后表达量显著增加。由此得出结论:喷施外源MeJA可以增强半夏中部分抗氧化酶的活性,保护半夏的细胞膜,增强细胞的渗透调节能力,且外源MeJA可能增加半夏高温胁迫响应基因的表达。     

Effects of Graded Levels of Tissue Oxygen Pressure on Dopamine Metabolism in the Striatum of Newborn Piglets

Abstract: The effect of graded levels of tissue hypoxia on the extracellular levels of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid has been monitored in vivo by microdialysis. Reproducible levels of decreased oxygen in the brain were obtained by increasing the rate of ventilation from the control value of 25/min to as high as 95/min. With increasing ventilatory rate, the oxygen pressure in the cortex decreased from ∼40 torr to 16 torr. As the oxygen pressure decreased stepwise from 40 to 27, 22, and 16 torr, the dopamine levels in the extracellular medium rose by 70, 90, and 150%, respectively, returning to baseline within a few minutes of return to control ventilation rates. Levels of the catabolic products 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid decreased with decreasing tissue oxygen. Unlike the dopamine levels, these catabolite levels continued to decrease through 30 min of recovery (to 50% of control), returning to baseline only after recovery periods of 1–2 h. These data suggest that hypoxia induces long-term alterations in the neurotransmitter turnover. The marked effects of mild tissue hypoxia (decrease of oxygen from 40 torr to 26 torr) on both the extracellular dopamine concentration and dopamine metabolism indicate that the metabolic consequences of decreased tissue oxygen pressure extend to higher values than generally appreciated.     

Proteasomes Associated with the Blm10 Activator Protein Antagonize Mitochondrial Fission through Degradation of the Fission Protein Dnm1

The conserved Blm10/PA200 activators bind to the proteasome core particle gate and facilitate turnover of peptides and unfolded proteins in vitro. We report here that Blm10 is required for the maintenance of functional mitochondria. BLM10 expression is induced 25-fold upon a switch from fermentation to oxidative metabolism. In the absence of BLM10, Saccharomyces cerevisiae cells exhibit a temperature-sensitive growth defect under oxidative growth conditions and produce colonies with dysfunctional mitochondria at high frequency. Loss of BLM10 leads to reduced respiratory capacity, increased mitochondrial oxidative damage, and reduced viability in the presence of oxidative stress or death stimuli. In the absence of BLM10, increased fragmentation of the mitochondrial network under oxidative stress is observed indicative of elevated activity of the mitochondrial fission machinery. The degradation of Dnm1, the main factor mediating mitochondrial fission, is impaired in the absence of BLM10 in vitro and in vivo. These data suggest that the mitochondrial functional and morphological changes observed are related to elevated Dnm1 levels. This hypothesis is supported by the finding that cells that constitutively overexpress DNM1 display the same mitochondrial defects as blm10Δ cells. The data are consistent with a model in which Blm10 proteasome-mediated turnover of Dnm1 is required for the maintenance of mitochondrial function and provides cytoprotection under conditions that induce increased mitochondrial damage and programmed cell death.     

Stress sensitivity and the development of affective disorders

Depressive disorders are the most common form of mental illness in America, affecting females twice as often as males. The great variability of symptoms and responses to therapeutic treatment emphasize the complex underlying neurobiology of disease onset and progression. Evidence from human and animal studies reveals a vital link between individual stress sensitivity and the predisposition toward mood disorders. While the stress response is essential for maintenance of homeostasis and survival, chronic stress and maladaptive responses to stress insults can lead to depression or other affective disorders. A key factor in the mediation of stress responsivity is the neuropeptide corticotropin-releasing factor (CRF). Studies in animal models of heightened stress sensitivity have illustrated the involvement of CRF downstream neurotransmitter targets, including serotonin and norepinephrine, in the profound neurocircuitry failure that may underlie maladaptive coping strategies. Stress sensitivity may also be a risk factor in affective disorder development susceptibility. As females show an increased stress response and recovery time compared to males, they may be at an increased vulnerability for disease. Therefore, examination of sex differences in CRF and downstream targets may aid in the elucidation of the underlying causes of the increased disease presentation in females. While we continue to make progress in our understanding of mood disorder etiology, we still have miles to go before we sleep. As an encouraging number of new animal models of altered stress sensitivity and negative stress coping strategies have been developed, the future looks extremely promising for the possibility of a new generation of drug targets to be developed.     

CRF type 1 receptors of the medial amygdala modulate inhibitory avoidance responses in the elevated T-maze

Corticotropin-releasing factor (CRF) plays a critical role in the mediation of physiological and behavioral responses to stressors. In the present study, we investigated the role played by the CRF system within the medial amygdala (MeA) in the modulation of anxiety and fear-related responses. Male Wistar rats were bilaterally administered into the MeA with CRF (125 and 250 ng/0.2 μl, experiment 1) or with the CRFR1 antagonist antalarmin (25 ng/0.2 μl, experiment 2) and 10 min later tested in the elevated T-maze (ETM) for inhibitory avoidance and escape measurements. In clinical terms, these responses have been respectively related to generalized anxiety and panic disorder. To further verify if the anxiogenic effects of CRF were mediated by CRFR1 activation, we also investigated the effects of the combined treatment with CRF (250 ng/0.2 μl) and antalarmin (25 ng/0.2 μl) (experiment 3). All animals were tested in an open field, immediately after the ETM, for locomotor activity assessment. Results showed that CRF, in the two doses administered, facilitated ETM avoidance, an anxiogenic response. Antalarmin significantly decreased avoidance latencies, an anxiolytic effect, and was able to counteract the anxiogenic effects of CRF. None of the compounds administered altered escape responses or locomotor activity measurements. These results suggest that CRF in the MeA exerts anxiogenic effects by activating type 1 receptors, which might be of relevance to the physiopathology of generalized anxiety disorder.     

水杨酸对香荚兰抗逆相关酶的活性和丙二醛含量的影响

对大田栽培的香荚兰植株进行不同浓度的水杨酸(SA)处理,结果表明：较低浓度(25～100mg/L)的SA,使其叶片的SOD、POD、PAL和PPO活性增加,MDA含量降低,抗逆性增强;而较高浓度的SA(150～200mg/L)则抑制了这些酶的活性、使MDA含量升高,抗逆性减弱。     

Proline Biosynthesis Is Required for Endoplasmic Reticulum Stress Tolerance in Saccharomyces cerevisiae

The amino acid proline is uniquely involved in cellular processes that underlie stress response in a variety of organisms. Proline is known to minimize protein aggregation, but a detailed study of how proline impacts cell survival during accumulation of misfolded proteins in the endoplasmic reticulum (ER) has not been performed. To address this we examined in Saccharomyces cerevisiae the effect of knocking out the PRO1, PRO2, and PRO3 genes responsible for proline biosynthesis. The null mutants pro1, pro2, and pro3 were shown to have increased sensitivity to ER stress relative to wild-type cells, which could be restored by proline or the corresponding genetic complementation. Of these mutants, pro3 was the most sensitive to tunicamycin and was rescued by anaerobic growth conditions or reduced thiol reagents. The pro3 mutant cells have higher intracellular reactive oxygen species, total glutathione, and a NADP⁺/NADPH ratio than wild-type cells under limiting proline conditions. Depletion of proline biosynthesis also inhibits the unfolded protein response (UPR) indicating proline protection involves the UPR. To more broadly test the role of proline in ER stress, increased proline biosynthesis was shown to partially rescue the ER stress sensitivity of a hog1 null mutant in which the high osmolality pathway is disrupted.     

产乳酸凝结芽胞杆菌N001的抗逆性研究

目的研究前期经初筛的产乳酸凝结芽胞杆菌N001芽胞的抗逆性。方法在模拟饲料制粒条件下和动物消化道内逆境条件下的存活能力,测定N001芽胞的抗热、抗酸、耐胆盐性能和对抗生素的敏感性。结果凝结芽胞杆菌N001芽胞具有很强的耐高温、耐酸、耐胆盐能力;同时N001芽胞对营养体敏感的抗生素也有良好的耐受性。结论凝结芽胞杆菌N001芽胞具有很强的抗逆性,可以作为益生菌制剂的良好菌种。     

Women's physical and psychological condition independently predict their preference for apparent health in faces

Physical condition (e.g., health, fertility) influences female mate preferences in many species, with females in good condition preferring "higher quality" (e.g., healthier) mates. In humans, condition may comprise both physical (e.g., health and fertility) and psychological factors (e.g., stress, anxiety, and depression). We found that women with low waist-to-hip ratios (indicating health and fertility) or who scored low on anxiety, depression, and stress measures expressed greater attraction to composite male (but not female) faces with color and texture cues associated with apparent health than did women with relatively high waist-to-hip ratios or who scored relatively high on the anxiety, depression, and stress measures. These effects of physical and psychological condition were independent and were not mediated by women's perceptions of their own attractiveness. Our findings indicate that women's physical and psychological conditions both contribute to individual differences in face preferences.