Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Stress

  • Reynold shear stress
  • Reynold stress
  • abiotic stress
  • acid stress
  • acute psychological stress
  • acute restraint stress
  • acute stress
  • additional stress
  • al stress
  • anaerobic stress
  • anthropogenic stress
  • applied stress
  • au stress
  • bending stress
  • biomechanical stress
  • biotic stress
  • bone stress
  • cadmium stress
  • cardiac stress
  • caregiver stress
  • cell stress
  • cellular oxidative stress
  • cellular stress
  • chemical stress
  • chilling stress
  • chronic mild stress
  • chronic oxidative stress
  • chronic psychosocial stress
  • chronic restraint stress
  • chronic social stress
  • chronic stress
  • circumferential wall stress
  • climatic stress
  • cold stress
  • compression stress
  • compressive residual stress
  • compressive stress
  • compressive yield stress
  • constant stress
  • contact stress
  • contraction stress
  • copper stress
  • desiccation stress
  • developmental stress
  • different stress
  • drought stress
  • early stress
  • economic stress
  • effective stress
  • emotional stress
  • endoplasmic reticulum stress
  • energetic stress
  • energy stress
  • environmental stress
  • equivalent stress
  • er stress
  • ethanol stress
  • excessive stress
  • experience stress
  • external stress
  • failure stress
  • family stress
  • film stress
  • financial stress
  • fiscal stress
  • flow stress
  • fluid shear stress
  • food stress
  • fracture stress
  • genotoxic stress
  • great stress
  • heat stress
  • high oxidative stress
  • high shear stress
  • high stress
  • high-salinity stress
  • highest stress
  • horizontal stress
  • hyperosmotic stress
  • hypertonic stress
  • hypo-osmotic stress
  • hypoxic stress
  • immobilization stress
  • in-plane stress
  • increased oxidative stress
  • increased stress
  • induced oxidative stress
  • inescapable stress
  • inflammatory stress
  • initial stress
  • interfacial shear stress
  • internal stress
  • job stress
  • large stress
  • lateral stress
  • life stress
  • light stress
  • local stress
  • low stress
  • low-temperature stress
  • lower stress
  • macroscopic stress
  • maternal emotional stress
  • maternal stress
  • maximum stress
  • mean stress
  • mechanical stress
  • mental stress
  • metabolic stress
  • metal stress
  • mild stress
  • mise stress
  • mitochondrial oxidative stress
  • moisture stress
  • multiple stress
  • nacl stress
  • nitrosative stress
  • non-linear stress
  • normal stress
  • novelty stress
  • nutrient stress
  • nutritional stress
  • o3 stress
  • occupational stress
  • of stress
  • orthostatic stress
  • osmotic stress
  • other stress
  • oxidant stress
  • oxidative stress
  • oxygen stress
  • parental stress
  • parenting stress
  • peak stress
  • perceived job stress
  • perceived stress
  • ph stress
  • photo-oxidative stress
  • physical stress
  • physiological stress
  • plane stress
  • post-traumatic stress
  • posttraumatic stress
  • predator stress
  • prenatal stress
  • principal stress
  • psychological stress
  • psychosocial stress
  • renal oxidative stress
  • residual compressive stress
  • residual stress
  • restraint stress
  • reticulum stress
  • role stress
  • saline stress
  • salinity stress
  • salt stress
  • severe stress
  • severe water stress
  • shear stress
  • significant oxidative stress
  • significant stress
  • sintering stress
  • situ stress
  • social stress
  • soil water stress
  • subjective stress
  • surface stress
  • surgical stress
  • systemic oxidative stress
  • tectonic stress
  • temperature stress
  • tensile stress
  • thermal stress
  • tissue stress
  • traumatic stress
  • true stress
  • ultimate stress
  • uniaxial stress
  • variety of stress
  • various stress
  • vertical stress
  • vivo oxidative stress
  • von mise stress
  • wall shear stress
  • wall stress
  • water stress
  • water-deficit stress
  • wind stress
  • work stress
  • work-related stress
  • yield stress

  • Terms modified by Stress

  • stress activation
  • stress adaptation
  • stress agent
  • stress amplitude
  • stress analysis
  • stress appraisal
  • stress being
  • stress biomarker
  • stress change
  • stress component
  • stress concentration
  • stress concentration factor
  • stress concept
  • stress condition
  • stress corrosion cracking
  • stress criterion
  • stress data
  • stress decreased
  • stress dependence
  • stress development
  • stress difference
  • stress direction
  • stress disorder
  • stress disorder scale
  • stress disorder symptom
  • stress distribution
  • stress echocardiogram
  • stress echocardiography
  • stress effect
  • stress effects
  • stress environment
  • stress equation
  • stress event
  • stress experience
  • stress experiment
  • stress exponent
  • stress exposure
  • stress factor
  • stress fiber
  • stress fiber formation
  • stress fibre
  • stress field
  • stress fracture
  • stress fractures
  • stress function
  • stress generation
  • stress gradient
  • stress gradient hypothesis
  • stress granule
  • stress group
  • stress history
  • stress hormone response
  • stress hormones
  • stress hyperglycemia
  • stress hypothesis
  • stress incontinence
  • stress increase
  • stress index
  • stress indicator
  • stress induction
  • stress injury
  • stress intensity
  • stress intensity factor
  • stress invariant
  • stress lead
  • stress leading
  • stress level
  • stress magnitude
  • stress management
  • stress management skill
  • stress marker
  • stress measurement
  • stress metabolite
  • stress model
  • stress models
  • stress paradigm
  • stress parameter
  • stress paths
  • stress pathway
  • stress perception
  • stress perturbation
  • stress physiology
  • stress problem
  • stress profile
  • stress protection
  • stress protein
  • stress questionnaire
  • stress range
  • stress rate
  • stress ratio
  • stress reaction
  • stress reactivity
  • stress reduction
  • stress regime
  • stress regulation
  • stress relate
  • stress relaxation
  • stress research
  • stress resistance
  • stress response
  • stress response gene
  • stress response mechanism
  • stress response pathway
  • stress responsiveness
  • stress scale
  • stress score
  • stress sensitivity
  • stress sensor
  • stress signal
  • stress singularity
  • stress situation
  • stress space
  • stress state
  • stress states
  • stress stimulus
  • stress study
  • stress survival
  • stress symptom
  • stress symptomatology
  • stress syndrome
  • stress system
  • stress task
  • stress tensor
  • stress test
  • stress testing
  • stress theory
  • stress tolerance
  • stress transfer
  • stress treatment
  • stress ui
  • stress ulcer
  • stress urinary incontinence
  • stress value
  • stress wave

  • Selected Abstracts


    ADDICTION, Issue 8 2009
    No abstract is available for this article. [source]


    EVOLUTION, Issue 3 2009
    Mark E. Sherrard
    Environmental stress can alter genetic variation and covariation underlying functional traits, and thus affect adaptive evolution in response to natural selection. However, the genetic basis of functional traits is rarely examined in contrasting resource environments, and consequently, there is no consensus regarding whether environmental stress constrains or facilitates adaptive evolution. We tested whether resource availability affects genetic variation for and covariation among seven physiological traits and seven morphological/performance traits by growing the annual grass Avena barbata in dry and well-watered treatments. We found that differences in the overall genetic variance,covariance (G) matrix between environments were driven by physiological traits rather than morphology and performance traits. More physiological traits were heritable in the dry treatment than the well-watered treatment and many of the genetic correlations among physiological traits were environment dependent. In contrast, genetic variation and covariation among the morphological and performance traits did not differ across treatments. Furthermore, genetic correlations between physiology and performance were stronger in the dry treatment, which contributed to differences in the overall G -matrix. Our results therefore suggest that physiological adaptation would be constrained by low heritable variation in resource-rich environments, but facilitated by higher heritable variation and stronger genetic correlations with performance traits in resource-poor environments. [source]


    EVOLUTION, Issue 2 2004
    W. Talloen
    Abstract Evolutionary studies typically focus on adaptations to particular environmental conditions, thereby often ignoring the role of possible constraints. Here we focus on the case of variation in dorsal wing melanization in a satyrine butterfly Pararge aegeria. Because melanin is a complex polymer, its synthesis may be constrained if ambient conditions limit the resource budget. This hypothesis was tested by comparing melanization among butterflies that fed as larvae on host grasses experiencing different drought-stress treatments. Treatment differences were validated both at the level of the host plant (nitrogen, carbonate, and water content) and of the butterfly (life-history traits: survival, development time, and size at maturity). Melanization rate was measured as average gray value of the basal dorsal wing area. This area, close to the thorax, is known to be functionally significant for basking in order to thermoregulate. Individuals reared on drought-stressed host plants developed paler wings, and development of darker individuals was slower and less stable as estimated by their level of fluctuating asymmetry. These results provide evidence that melanin is indeed costly to synthesize, and that differences in environmental quality can induce phenotypic variation in wing melanization. Therefore, studies dealing with spatial and/or temporal patterns of variation in wing melanization should not focus on adaptive explanations alone, but rather on a cost-benefit balance under particular sets of environmental conditions. [source]

    DROUGHT STRESS: Comparative Time Course Action of the Foliar Applied Glycinebetaine, Salicylic Acid, Nitrous Oxide, Brassinosteroids and Spermine in Improving Drought Resistance of Rice

    M. Farooq
    Abstract Worldwide rice productivity is being threatened by increased endeavours of drought stress. Among the visible symptoms of drought stress, hampered water relations and disrupted cellular membrane functions are the most important. Exogenous use of polyamines (PAs), salicylic acid (SA), brassinosteroids (BRs), glycinebetaine (GB) and nitrous oxide (NO) can induce abiotic stresses tolerance in many crops. In this time course study, we appraised the comparative role of all these substances to improve the drought tolerance in rice (Oryza sativa L.) cultivar Super-Basmati. Plants were subjected to drought stress at four leaf stage (4 weeks after emergence) by maintaining soil moisture at 50 % of field capacity. Pre-optimized concentrations of GB (150 mg l,1), SA (100 mg l,1), NO (100 ,mol l,1 sodium nitroprusside as NO donor), BR (0.01 ,m 24-epibrassinolide) and spermine (Spm; 10 ,m) were foliar sprayed at five-leaf stage (5 weeks after emergence). There were two controls both receiving no foliar spray, viz. well watered (CK1) and drought stressed (CK2). There was substantial reduction in allometric response of rice, gas exchange and water relation attributes by drought stress. While drought stress enhanced the H2O2, malondialdehyde (MDA) and relative membrane permeability, foliar spray of all the chemicals improved growth possibly because of the improved carbon assimilation, enhanced synthesis of metabolites and maintenance of tissue water status. Simultaneous reduction in H2O2 and MDA production was also noted in the plants treated with these substances. Drought tolerance was sturdily associated with the greater tissue water potential, increased synthesis of metabolites and enhanced capacity of antioxidant system. Of all the chemicals, foliar spray with Spm was the most effective followed by BR. [source]

    DROUGHT STRESS: Role of Carbohydrate Metabolism in Drought-Induced Male Sterility in Rice Anthers,

    G. N. Nguyen
    Abstract Rice plants exposed to three consecutive days of water stress (,0.5 MPa) show a reduction in male fertility and grain set, which is attributed to increased levels of reactive oxygen species (ROS) and activation of a programmed cell death. This current research was conducted to further investigate the association of sugar metabolism with microspore abortion in rice anthers. Biochemical assays showed that sucrose, glucose and fructose contents were found to be significantly increased in anthers from water stressed plants compared with the control. qRT-PCR analyses and in situ hybridization of metabolic genes (sugar transporters, invertase and phosphotransferase/kinases) demonstrated that the supply of sugars for developing microspores and the initial steps of sugar utilization e.g. glycolysis, were not repressed. However, it appears that the accumulation of sugars in stressed anthers might involve a reduction of mitochondrial activity during the tricarboxylic acid cycle, which could result in excessive production of ROS and a depletion of the ATP pool. These results also suggest that higher levels of sugars at all stages of anther development seemed to be associated with some measure of protection to the anthers against oxidative stress. Induced expression of sugar transporter genes might have maintained the high levels of sugar in the tapetum and the locules, which alleviated oxidant damage caused by excessive ROS generation. Thus, the increased level of sugars might potentially be a natural response in providing protection against oxidant damage by strengthening the antioxidant system in anthers. [source]


    Reduced and oxidized glutathione was assayed in wheat, barley, rye, oats and buckwheat before and after extrusion cooking. The results obtained indicate that GSH/GSSG ratio was decreased from 1.91 and 10.72 for raw oat and buckwheat grains to the 1.13, 1.01, 1.10 and 4.72, 3.89, 3.89 for extruded material, respectively, in temperature used of 120, 160 and 200C. These results indicate that the oxidative stress is least developed during extrusion cooking of oat and buckwheat grains. Wheat and barley grains were more prone to oxidative damage, and the observed decrease of the ratio ranged from 6.84 and 4.89 (wheat cv. Almari and barley cv. Mobek, raw material) to the 1.89 and 2.07 (after extrusion cooking at 200C, respectively). No significance differences were found between two cultivars of wheat and barley being used in the experiment. The most decreased ratio up to five times was found in rye grain extrudates. The extrusion performed under barrel temperature profile of 80,100,120,120,120C caused significant decrease in GSH content when compared to raw material. The next higher barrel temperature profiles of 100,130,160,160,120C and 120,160,200,200,120C led to further GSH decrease in extruded wheat grains. In contrast, the two high temperature profiles did not [source]


    ABSTRACT Because mineral composition data for lupins subjected to water stress (ws) are incomplete, it is essential to analyze those seeds in order to assess the quality of potential food source for both human and animal nutrition. So, we have performed chemical proximate analysis and determined the mineral profile of seeds from two lupins subjected to ws period and compared with seeds from well-watered (ww) plants. From the above results we can conclude that the values obtained fall within the range of values reported for both species (at ww conditions) and no significant (P > 0.05) differences were found in nutritional composition and mineral content between both lupins. Ws period was responsible for a significant increase in sugar, ash, both macroelements (Ca, Na, K, Mg) and microelements (Fe, Zn, Mn, Cu) as well as phytate content. The results obtained are relevant for selection of better mineral nutritive value of seeds from lupin species. [source]


    Briana S. Nelson Goff
    Research traditionally has focused on the development of symptoms in those who experienced trauma directly but overlooked the impact of trauma on the families of victims. In recent years, researchers and clinicians have begun to examine how individual exposure to traumatic stress affects the spouses/partners, children, and professional helpers of trauma survivors. However, empirically supported, theory-based literature that identifies the mechanisms by which interpersonal or "secondary trauma" occurs in response to traumatic events is limited. Here, we present the Couple Adaptation to Traumatic Stress Model, a systemic model of the development of interpersonal symptoms in the couple dyad based on empirical literature. Potential mechanisms and clinical vignettes are included to describe the systemic processes that occur with trauma couples. Areas for future research and clinical implications also are identified. [source]


    Rachel Lev-Wiesel
    In this study, we examined the issue of secondary traumatic stress (STS) among spouses of Holocaust survivors who were children during the World War II. STS is defined as comprising the same components as posttraumatic stress disorder (PTSD), except that the person evidencing the symptoms has not actually been exposed to the traumatic event(s), but has developed them as a result of caring for someone with PTSD. Participants were 90 couples who completed self-report questionnaires regarding posttraumatic symptoms, psychological distress, and marital quality. The results showed that about one-third of the spouses suffered from some degree of STS symptoms. Secondary traumatic stress symptoms and psychological distress among spouses were significantly related to hostility, anger, paranoia, and interpersonal sensitivity in the survivor, but unrelated to whether the survivor had shared his/her reminiscences with the spouse. Female spouses were found to suffer more distress than male spouses, especially when their partner suffered high levels of PTSD. The results suggest that STS is, to a large degree, related to the demands of living with a symptomatic survivor, possibly more than to the empathic element thought to be central to this syndrome. [source]


    JOURNAL OF PHYCOLOGY, Issue 5 2006
    Silvia K. Kawakami
    Phytoplankton deal with metal toxicity using a variety of biochemical strategies. One of the strategies involves glutathione (GSH) and phytochelatins (PCs), which are metal-binding thiol peptides produced by eukaryotes and these compounds have been related to several intracellular functions, including metal detoxification, homeostasis, metal resistance and protection against oxidative stress. This paper assesses our state of knowledge on the production of PCs and GSH by marine phytoplankton in laboratory and field conditions and the possible applications of PCs for environmental purposes. Good relationships have been observed between metal exposure and PC production in phytoplankton in the laboratory with Cd, Pb, and Zn showing the greatest efficacy, thereby indicating that PCs have a potential for application as a biomarker. Fewer studies on PC distributions in particulate material have been undertaken in the field. These studies show that free Cu has a strong relationship with the levels of PC in the particulate material. The reason for this could be because Cu is a common contaminant in coastal waters. However it could also be due to the lack of measurements of other metals and their speciation. GSH shows a more complex relationship to metal levels both in the laboratory and in the field. This is most likely due to its multifunctionality. However, there is evidence that phytoplankton act as an important source of dissolved GSH in marine waters, which may form part of the strong organic ligands that control metal speciation, and hence metal toxicity. [source]


    JOURNAL OF PHYCOLOGY, Issue 4 2001
    Jean-Paul Parkhill
    In biological oceanography, it has been widely accepted that the maximum quantum yield of photosynthesis is influenced by nutrient stress. A closely related parameter, the maximum quantum yield for stable charge separation of PSII, (,PSII)m, can be estimated by measuring the increase in fluorescence yield from dark-adapted minimal fluorescence (Fo) to maximal fluorescence (Fm) associated with the closing of photosynthetic reaction centers with saturating light or with a photosynthetic inhibitor such as 3,-(3,4-dichlorophenyl)-1,,1,-dimethyl urea (DCMU). The ratio Fv/Fm (= (Fm, Fo)/Fm) is thus used as a diagnostic of nutrient stress. Published results indicate that Fv/Fm is depressed for nutrient-stressed phytoplankton, both during nutrient starvation (unbalanced growth) and acclimated nutrient limitation (steady-state or balanced growth). In contrast to published results, fluorescence measurements from our laboratory indicate that Fv/Fm is high and insensitive to nutrient limitation for cultures in steady state under a wide range of relative growth rates and irradiance levels. This discrepancy between results could be attributed to differences in measurement systems or to differences in growth conditions. To resolve the uncertainty about Fv/Fm as a diagnostic of nutrient stress, we grew the neritic diatom Thalassiosira pseudonana (Hustedt) Hasle et Heimdal under nutrient-replete and nutrient-stressed conditions, using replicate semicontinuous, batch, and continuous cultures. Fv/Fm was determined using a conventional fluorometer and DCMU and with a pulse amplitude modulated (PAM) fluorometer. Reduction of excitation irradiance in the conventional fluorometer eliminated overestimation of Fo in the DCMU methodology for cultures grown at lower light levels, and for a large range of growth conditions there was a strong correlation between the measurements of Fv/Fm with DCMU and PAM (r2 = 0.77, n = 460). Consistent with the literature, nutrient-replete cultures showed consistently high Fv/Fm (,0.65), independent of growth irradiance. Under nutrient-starved (batch culture and perturbed steady state) conditions, Fv/Fm was significantly correlated to time without the limiting nutrient and to nutrient-limited growth rate before starvation. In contrast to published results, our continuous culture experiments showed that Fv/Fm was not a good measure of nutrient limitation under balanced growth conditions and remained constant (,0.65) and independent of nutrient-limited growth rate under different irradiance levels. Because variable fluorescence can only be used as a diagnostic for nutrient-starved unbalanced growth conditions, a robust measure of nutrient stressed oceanic waters is still required. [source]


    ALCOHOLISM, Issue 2008
    Sunju Sohn
    Aims:, Young male adults in the U. S. military drink at much higher rates than civilians and females of the same age. Drinking has been shown to be associated with stress and individuals' ability to effectively cope with stressors. Despite numerous studies conducted on young adults' drinking behaviors such as college drinking, current literature is limited in fully understanding alcohol use patterns of the young military population. The aim of the present study was to develop and test the hypothesized Structural Equation Model (SEM) of alcohol use to determine if stress coping styles moderate the relationship between stress, drinking motives, impulsivity, alcohol consumption and job performance. Methods:, Structural equation models for multiple group comparisons were estimated based on a sample of 1,715 young (aged 18 to 25) male military personnel using the 2005 Department of Defense Survey of Health Related Behaviors among Military Personnel. Coping style was used as the grouping factor in the multi-group analysis and this variable was developed through numerous steps to reflect positive and negative behaviors of coping. The equivalences of the structural relations between the study variables were then compared across two groups at a time, controlling for installation region, race/ethnicity, marital status, education, and pay grade, resulting in two model comparisons with four coping groups. If the structural weight showed differences across groups, each parameter was constrained and tested one at a time to see where the models are different. Results:, The results showed that the hypothesized model applies across all groups. The structural weights revealed that a moderation effect exists between a group whose tendency is to mostly use positive coping strategies and a group whose tendency is to mostly use negative coping strategies (,,2(39)= 65.116, p<.05). More specifically, the models were different (with and without Bonferroni Type I error correction) in the paths between "motive and alcohol use" and "alcohol use and alcohol-related consequences (job performance)." Conclusions:, It seems plausible that coping style significantly factors into moderating alcohol use among young male military personnel who reportedly drink more excessively than civilians of the same age. The results indicate that it may be particularly important for the military to assess different stress coping styles ofyoung male military personnel so as to limit excessive drinking as well as to promote individual wellness and improve job performance. [source]


    Li-Xia Lou
    SUMMARY 1Iron overload contributes to the pathogenesis of various diseases and directly induces tissue injury. In the present study, we investigated the relationship between heart and liver injury induced by iron overload and cellular endoplasmic reticulum (ER) stress to explore the molecular mechanism of iron overload-induced cellular injury. 2Iron overload in rats was generated by intraperitoneal injection of iron,dextran chronically (30 mg/kg per day for 9 weeks) or acutely (300 mg/kg once). Tissue injury was assessed by determining serum lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, as well as malondialdehyde (MDA) content in the heart and liver. The ER stress response was analysed by expression of glucose-response protein 78 (GRP78) and activation of caspase 12. 3In chronic iron-loaded rats, iron levels in the heart and liver were higher, by approximately 2-and 7.8-fold, respectively (P < 0.01), compared with control. Serum LDH, ALT and AST activity, as well as MDA content, GRP78 expression and caspase 12 activity in the heart and liver, were upregulated in chronically iron-loaded rats. In acute iron-loaded rats, iron content in the heart and liver was 51% and 63% higher than in controls (both P < 0.01). Serum LDH, ALT and AST activity, MDA content in the heart and liver and levels of ER stress markers were all increased in acute iron-loaded rats. N -Acetylcysteine (150 mg/kg, s.c.) lowered the levels of these parameters in acute iron-loaded rats. 4The results of the present study indicate that ER stress may play an important role in iron-induced tissue injury and that reactive oxygen species may mediate the ER stress response in the pathogenesis of iron-overload cellular injury. [source]


    Elenara Rieger
    SUMMARY 1Glycerol has been used for the treatment of intracranial hypertension, cerebral oedema and glaucoma. Experimentally, intramuscular administration of hypertonic glycerol solution is used to produce acute renal failure. In this model, glycerol causes rhabdomyolysis and myoglobinuria, resulting in the development of renal injury. The pathogenesis is thought to involve vascular congestion, the formation of casts and oxidative stress. However, the effect of glycerol itself independent of rhabdomyolysis has not been investigated. Therefore, the aim of the present study was to investigate the effects of i.p. glycerol on some biochemical and oxidative stress parameters in the kidney of young rats. 2Rats received 10 mL/kg, i.p., hypertonic glycerol solution (50% v/v) or saline (NaCl 0.85 g%) followed by 24 h water deprivation. Twenty-four hours after the administration of glycerol, rats were killed. Creatinine levels and the activity of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined in the plasma. In addition, CK, pyruvate kinase and LDH activity and oxidative stress parameters (free radical formation, lipid peroxidation and protein carbonylation) were measured in renal tissue. 3Glycerol did not alter plasma CK activity and increased plasma creatinine levels, suggesting renal insufficiency and the absence of rhabdomyolysis. Renal CK and pyruvate kinase activity was decreased, suggesting diminution of energy homeostasis in the kidney. Plasma and renal LDH activity was decreased, whereas the formation of free radicals, lipid peroxidation and protein carbonylation were increased, suggesting oxidative stress. 4These results are similar to those described after the intramuscular administration of glycerol. Therefore, it is possible that glycerol may provoke renal lesions by mechanisms other than those induced by rhabdomyolysis. [source]


    Vincent Lagente
    SUMMARY 1It was proposed previously that oxidative stress is a main component of the inflammatory process in chronic obstructive pulmonary disease (COPD). Thus, in the present study, we investigated the inflammatory response in mice deficient for the p47phox subunit of NADPH oxidase (p47 KO) exposed to cigarette smoke (CS). 2Exposure of mice to CS elicited an increase in the number of macrophages and neutrophils and levels of interleukin (IL)-6, keratinocyte-derived chemokine (KC/CXCL1) and monocyte chemoattractant protein-1 (MCP1/CCL2) in bronchoalveolar lavage fluid (BALF), which were lower in p47 KO mice compared with control mice. In contrast, 24 h after lipopolysaccharide (LPS) exposure, the number of macrophages and neutrophils, as well as KC/CXCL1 levels, in BALF was significantly greater in p47 KO mice compared with control mice. 3The present study has shown that airway inflammation is decreased in p47 KO mice after exposure to CS, but not LPS, suggesting that oxidative stress is involved in the pathogenesis of airway inflammation associated with COPD. [source]


    Yu Yamaguchi
    SUMMARY 1Oxidative stress has been recognized as an important factor in the biology of lifestyle-related diseases. Systemic oxidative stress may increase in metabolic syndrome characterized by a cluster of metabolic risk factors. To confirm this hypothesis, we investigated systemic oxidative/nitrative stress in a new congenic model of metabolic syndrome, namely SHRSP/ZF rats, which are derived from stroke-prone spontaneously hypertensive (SHRSP) and Zucker fatty (Zucker) rats. 2The SHRSP/ZF rats display obesity, hypertension, hyperlipidaemia, hyperglycaemia and glucose intolerance. At 6 weeks of age, SHRSP/ZF rats already showed increases in serum levels of thiobarbituric acid-reactive substances (TBARS) and oxidatively modified low-density lipoprotein (Ox-LDL) compared with lean SHRSP littermates and Zucker rats, whereas serum levels of 8-hydroxy-2,-deoxyguanine (8-OHdG), 3-nitrotyrosine, 3-chlorotyrosine and high-sensitivity C-reactive protein (hsCRP), an inflammatory marker, did not differ significantly among the three rat strains. However, levels of these oxidative/nirative stress markers in SHRSP/ZF rats, as well as in SHRSP, increased gradually with age. After 36 weeks of age, the levels of TBARS, 8-OHdG, 3-nitrotyrosine and hsCRP in SHRSP/ZF rats increased rapidly and three of six rats died thereafter. Increased oxidative/nitrative stress may be associated with death in these rats. 3Our findings indicate that systemic oxidative/nitrative stress is evidently increased in metabolic syndrome. [source]


    Z Sahnoun
    SUMMARY 1Severe cases of scorpion envenomation (SE) generally show both respiratory and cardiocirculatory dysfunction. However, the pathophysiology of SE remains controversial. In the present study, we tried to explain the pathophysiology of the haemodynamic perturbations and cardiac failure in rats poisoned by the venom of Buthus occitanus tunetanus through a histomorphometric study of myocardial and muscular skeletal microcirculation and analysis of the oxidative stress state in order to evaluate the implication of the inflammatory process in the pathogenesis of SE. 2Experiments were performed on 96 rats divided into 16 groups (n = 6 in each group). Two groups were used to determine the optimum conditions of venom administration and times when to measure haemodynamic parameters. The B. occitanus tunetanus venom was administered at a dose of 800 µg/kg and tissues were removed 5 and 20 min after envenomation. Six groups were used for histomorphometric study: two control groups, two poisoned groups an two melatonin-pretreated and poisoned groups. The histomorphometric study was performed on isolated hearts and skeletal muscles. The final eight groups of rats (two control groups, two envenomated groups, two control groups pretreated with melatonin and two groups pretreated and envenomated) were used to investigate the state of tissue oxidative stress during SE and to evaluate the anti-oxidant effect of melatonin on rats poisoned with B. occitanus tunetanus venom. This study was based on the determination of tissue malondialdehyde in isolated organs as an indicator of thiobarbituric acid-reactive substances (TBARS). Melatonin was injected at a dose of 5 mg/kg, i.v., 15 min before the administration of serum or venom. Data were compared using analysis of variance and Tukey's test for multiple pair-wise comparisons. 3Five minutes after venom injection, a significant reduction in the mean relative volume of venules and arterioles in the heart and skeletal muscles of poisoned rats was noted. Twenty minutes after venom injection, these volumes were significantly increased in the heart and skeletal muscles of poisoned rats. Pretreatment of envenomated rats with melatonin resulted in a significant decrease in the mean relative volume of the venules and arterioles in the heart and skeletal muscles 5 and 20 min after venom injection compared with untreated envenomated rats. Investigation of the oxidative stress state showed a highly significant increase in TBARS in poisoned rats compared with control groups 5 and 20 min after venom injection. Melatonin pretreatment of rats poisoned with B. occitanus tunetanus venom resulted in an important and highly significant reduction of TBARS compared with untreated envenomated rats. 4It appears from the results of the present study that administration of B. occitanus tunetanus venom engendered an excessive myocardial and skeletal muscular vasoconstriction attributed to massive catecholamine release followed by arteriolar and venular vasodilatation. This venous stasis at the muscular microcirculation could be due to myocardiac failure. However, the concomitant presence of arteriolar vasodilatation suggests an inflammatory process in the pathophysiology of SE. This process was suggested by the genesis of a state of oxidative stress in relation to the important lipoperoxidation, which was inhibited by administration of the anti-oxidant melatonin. Thus, melatonin pretreatment seemed to accentuate the first phase of vascular reactivity in envenomed rats and inhibit the second vasodilator phase observed 20 min after administration of the venom. [source]

    Noninvasive Stress and Reproductive Measures of Social and Ecological Pressures in Free-Ranging African Elephants

    C. A. H. Foley
    This, coupled with political pressures to delist the elephant, has created a need for noninvasive physiological measures that can quantify the long-term effects of past mortality patterns of this long-lived species. We collected fresh fecal samples from 16 female elephants in three different groups over 23 months at Tarangire National Park, Tanzania, and analyzed them for fecal progesterone and cortisol metabolites. Social and ecological measures were collected concurrently. Fecal progesterone metabolite measures corresponded significantly with stage of gestation, and appear to be able to confirm pregnancy in female elephants from as early as 3 months of gestation. We found that progesterone metabolite concentrations were significantly lower during the dry season than during the wet season after controlling for stage of gestation. Fecal cortisol metabolite concentrations showed the opposite seasonal pattern, being significantly higher in the dry season and inversely correlated with rainfall across seasons. Fecal cortisol metabolite concentrations also increased with group size and were correlated positively with dominance rank in the largest group. Our results suggest that measures of progesterone and cortisol metabolites in feces provide indices of reproductive function and physiological stress that can quantify both natural and human disturbances in African elephants. These measures are ideally suited for monitoring the long-term effects of social disruption from poaching and a variety of other management concerns. Resumen: Debido a la cacería furtiva, la población de elefante africano ( Loxodonta africana) declinó en un 60%, principalmente adultos, entre 1979 y 1988. Esto, aunado a presiones políticas para eliminar al elefante de las listas de especies en peligro, ha creado la necesidad de medidas fisiológicas no invasivas que puedan cuantificar efectos a largo plazo de patrones de mortalidad en el pasado de esta especie longeva. Recolectamos muestras fecales de 16 elefantes hembras en tres grupos diferentes en el Parque Nacional Tarangire, Tanzania a lo largo de 23 meses, y las analizamos para detectar metabolitos de progesterona fecal y de cortisol. Al mismo tiempo se recolectaron medidas sociales y ecológicas. Las medidas de metabolitos de progesterona fecal correspondieron significativamente con la etapa de gestación, y parecen permitir la confirmación de preñez en elefantes hembras tan temprano como a los tres meses de gestación. Las concentraciones de metabolitos de progesterona fueron significativamente menores durante la época de sequía que en la de lluvias después de controlar para la etapa de gestación. Las concentraciones de metabolitos de cortisol fecal mostraron un patrón estacional opuesto, siendo significativamente más altas en la época de sequía e inversamente correlacionados con la precipitación en todas las estaciones. Las concentraciones de metabolitos de cortisol fecal también incrementaron con el tamaño del grupo y se correlacionaron positivamente con el rango de dominancia en el grupo más grande. Nuestros resultados sugieren que las medidas de metabolitos de progesterona y cortisol en las heces proporcionan índices de la función reproductiva y del estrés fisiológico que puede cuantificar perturbaciones, tanto naturales como humanas, en elefantes africanos. Estas medidas son idealmente adecuadas para monitorear efectos a largo plazo de la disrupción social por la cacería furtiva y así como una variedad de aspectos del manejo. [source]

    Does PTSD occur in sentenced prison populations?

    A systematic literature review
    Background,A systematic review of the literature on mental disorder in prisoners, published in 2002, made no mention of post-traumatic stress disorder (PTSD), but indicators from other studies suggest that a history of serious and chronic trauma is common among offenders. Aims,To conduct a systematic review of the literature with the specific questions: does any epidemiological study of sentenced prisoners include data on prevalence of PTSD while in prison? If so, what is the prevalence in this group? Method,Literature databases EMBASE, Medline, PsychInfo, PILOTS and SIGLE were searched. The Journal of Traumatic Stress was searched manually. Preliminary screening was conducted by reading abstracts of hundreds of papers. Ten exclusion criteria were then applied to the screened selection. Reference sections of all accessed papers were searched for any further studies. Results,One hundred and three potentially relevant papers were identified after preliminary screening. Four met all criteria for inclusion and suffered none of the exclusion criteria. PTSD rates ranged from 4% of the sample to 21%. Women were disproportionately affected. Conclusions and implications for practice,All four papers suggested that the prevalence of PTSD among sentenced prisoners is higher than that in the general population, as reported elsewhere. Overall the findings suggest a likely need for PTSD treatment services for sentenced prisoners. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    China's Rangelands under Stress: A Comparative Study of Pasture Commons in the Ningxia Hui Autonomous Region

    Peter Ho
    China's economic reforms have exacerbated the problems of over-grazing and desertification in the country's pastoral areas. In order to deal with rangeland degradation, the Chinese government has resorted to nationalization, or semi-privatization. Since the implementation of rangeland policy has proved very difficult, however, experiments with alternative rangeland tenure systems merit our attention. In Ningxia, in northwest China, local attempts have been undertaken to establish communal range management systems with the village as the basic unit of use and control. Some of these management regimes are under severe stress, due to large-scale digging for medicinal herbs in the grasslands. This digging has resulted in serious conflicts between Han and Hui Muslim Chinese, during which several farmers have been killed. It is against this backdrop that this article explores the institutional dynamics of range management in two different villages. [source]

    Patient-assessed health outcome measures for diabetes: a structured review

    DIABETIC MEDICINE, Issue 1 2002
    A. M. Garratt
    Abstract Aims To identify available disease-specific measures of health-related quality of life (HRQL) for diabetes and to review evidence for the reliability, validity and responsiveness of instruments. Methods Systematic searches were used to identify instruments. Instruments were assessed against predefined inclusion and exclusion criteria. Letters were sent to authors requesting details of further instrument evaluation. Information relating to instrument content, patients, reliability, validity and responsiveness to change was extracted from published papers. Results The search produced 252 references. Nine instruments met the inclusion criteria: Appraisal of Diabetes Scale (ADS), Audit of Diabetes-Dependent Quality of Life (ADDQoL), Diabetes Health Profile (DHP-1, DHP-18), Diabetes Impact Measurement Scales (DIMS), Diabetes Quality of Life Measure (DQOL), Diabetes-Specific Quality of Life Scale (DSQOLS), Questionnaire on Stress in Diabetic Patients-Revised (QSD-R), Diabetes-39 (D-39) and Well-being Enquiry for Diabetics (WED). The shortest instrument (ADS) has seven items and the longest (WED) has 50 items. The ADS and ADDQoL are single-index measures. The seven multidimensional instruments have dimensions covering psychological well-being and social functioning but vary in the remainder of their content. The DHP-1 and DSQOLS are specific to Type 1 diabetes patients. The DHP-18 is specific to Type 2 diabetes patients. The DIMS and DQOL have weaker evidence for reliability and internal construct validity. Patients contributed to the content of the ADDQoL, DHP-1/18, DQOL, DSQOLS, D-39, QSD-R and WED. The authors of the ADDQoL, DHP-1/18, DQOL, DSQOLS gave explicit consideration to content validity. The construct validity of instruments was assessed through comparisons with instruments measuring related constructs and clinical and sociodemographic variables. None of the instruments has been formally assessed for responsiveness to changes in health. Conclusions Five of the diabetes-specific instruments have good evidence for reliability and internal and external construct validity: the ADDQoL, DHP-1/18, DSQOLS, D-39 and QSD-R. Instrument content should be assessed for relevance before application. The instruments should be evaluated concurrently for validity and responsiveness to important changes in health. [source]

    Segmental Contribution to Left Ventricular Systolic Function at Rest and Stress: A Quantitative Real Time Three-Dimensional Echocardiographic Study

    ECHOCARDIOGRAPHY, Issue 2 2010
    F.A.S.E., Smadar Kort M.D.
    Objective: To assess the relative contribution of each myocardial segment to global systolic function during stress using real time three-dimensional echocardiography (RT3DE). Background: During stress, global augmentation in contractility results in an increased stroke volume. The relative contribution of each myocardial segment to these volumetric changes is unknown. Methods: Full volume was acquired using RT3DE at rest and following peak exercise in 22 patients who had no ischemia and no systolic dyssynchrony on two-dimensional (2D) stress echocardiography. The following were calculated at rest and peak stress: end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), relative SV, and relative EF. Results: With stress, an increase in global EDV from 90.8 to 101.1 ml (P < 0.001), SV from 59 to 78.4 ml (P = 0.01), and EF from 65.6 to 78.4% (P = 0.001) was observed. ESV decreased from 31.8 to 22.7 ml (P < 0.001). Segmental analysis revealed significantly higher SV, relative SV, and relative EF for the basal anterior, basal anterolateral, and basal inferolateral segments compared with the apical septum and apical inferior segments at both rest and stress (P < 0.001). The SV, relative SV, and relative EF increased significantly from apex to mid to base at both rest and stress (P < 0.001). Conclusions: The relative volumetric contribution of each myocardial segment to global left ventricular systolic function at rest and stress is not uniform. The basal segments contribute more than the mid and apical segments. Specifically, the basal anterior, basal anterolateral, and basal inferolateral segments contribute the most to augmentation of left ventricular systolic function with exercise. (ECHOCARDIOGRAPHY 2010;27:167-173) [source]

    Real Time Myocardial Contrast Echocardiography During Supine Bicycle Stress and Continuous Infusion of Contrast Agent.

    ECHOCARDIOGRAPHY, Issue 6 2007
    Cutoff Values for Myocardial Contrast Replenishment Discriminating Abnormal Myocardial Perfusion
    Background: Myocardial contrast echocardiography (MCE) is a new imaging modality for diagnosing coronary artery disease (CAD). Objective: The aim of our study was to evaluate feasibility of qualitative myocardial contrast replenishment (RP) assessment during supine bicycle stress MCE and find out cutoff values for such analysis, which could allow accurate detection of CAD. Methods: Forty-four consecutive patients, scheduled for coronary angiography (CA) underwent supine bicycle stress two-dimensional echocardiography (2DE). During the same session, MCE was performed at peak stress and post stress. Ultrasound contrast agent (SonoVue) was administered in continuous mode using an infusion pump (BR-INF 100, Bracco Research). Seventeen-segment model of left ventricle was used in analysis. MCE was assessed off-line in terms of myocardial contrast opacification and RP. RP was evaluated on the basis of the number of cardiac cycles required to refill the segment with contrast after its prior destruction with high-power frames. Determination of cutoff values for RP assessment was performed by means of reference intervals and receiver operating characteristic analysis. Quantitative CA was carried out using CAAS system. Results: MCE could be assessed in 42 patients. CA revealed CAD in 25 patients. Calculated cutoff values for RP-analysis (peak-stress RP >3 cardiac cycles and difference between peak stress and post stress RP >0 cardiac cycles) provided sensitive (88%) and accurate (88%) detection of CAD. Sensitivity and accuracy of 2DE were 76% and 79%, respectively. Conclusions: Qualitative RP-analysis based on the number of cardiac cycles required to refill myocardium with contrast is feasible during supine bicycle stress MCE and enables accurate detection of CAD. [source]

    Vasodilator Stress Induces Infrequent Wall Thickening Abnormalities Compared to Perfusion Defects in Mild-to-Moderate Coronary Artery Disease: Implications for the Choice of Imaging Modality with Vasodilator Stress

    ECHOCARDIOGRAPHY, Issue 4 2004
    M.R.C.P., Ph.D., Prem Soman M.D.
    Background: Experimental evidence suggests that although vasodilator stress agents consistently induce regional flow disparity between stenosed and normal coronary vascular beds, the occurrence of functional myocardial ischemia is infrequent, especially in mild-to-moderate coronary artery stenosis. Thus, it is hypothesized that dipyridamole infusion, even at high doses, will result in a disproportionately higher frequency of perfusion defects compared to regional wall thickening abnormalities. Methods: We performed simultaneous high-dose (0.84 mg/kg) dipyridamole stress echocardiography (Echo) and Tc-99m sestamibi SPECT (MIBI, methoxyisobutyl isonitrile) in 46 patients with coronary artery diameter stenosis >50% and ,90% in one or two epicardial coronary arteries, and no previous myocardial infarction. Results: Of a total of 828 segments, MIBI showed 97 reversible defects while Echo showed only 23 reversible wall thickening abnormalities. Of the 97 segments with reversible MIBI defects, only 13 (13%) showed simultaneous reversible wall thickening abnormalities during dipyridamole infusion. There were 24 patients with MIBI defects, of whom 10 (41%) showed a corresponding wall thickening abnormality. The sensitivity of MIBI and Echo for the detection of coronary artery disease was 52% and 21%, respectively (P = 0.001). Conclusion: This suggests that vasodilator stress is not optimally suited for use with techniques that use regional wall thickening abnormality as a marker of ischemia for the diagnosis of coronary artery disease. (ECHOCARDIOGRAPHY, Volume 21, May 2004) [source]

    Stress, the hippocampus, and epilepsy

    EPILEPSIA, Issue 4 2009
    Marian Joëls
    Summary Stress is among the most frequently self-reported precipitants of seizures in patients with epilepsy. This review considers how important stress mediators like corticotropin-releasing hormone, corticosteroids, and neurosteroids could contribute to this phenomenon. Cellular effects of stress mediators in the rodent hippocampus are highlighted. Overall, corticosterone,with other stress hormones,rapidly enhances CA1/CA3 hippocampal activity shortly after stress. At the same time, corticosterone starts gene-mediated events, which enhance calcium influx several hours later. This later effect serves to normalize activity but also imposes a risk for neuronal injury if and when neurons are concurrently strongly depolarized, for example, during epileptic activity. In the dentate gyrus, stress-induced elevations in corticosteroid level are less effective in changing membrane properties such as calcium influx; here, enhanced inhibitory tone mediated through neurosteroid effects on ,-aminobutyric acid (GABA) receptors might dominate. Under conditions of repetitive stress (e.g., caused from experiencing repetitive and unpredictable seizures) and/or early life stress, hormonal influences on the inhibitory tone, however, are diminished; instead, enhanced calcium influx and increased excitation become more important. In agreement, perinatal stress and elevated steroid levels accelerate epileptogenesis and lower seizure threshold in various animal models for epilepsy. It will be interesting to examine how curtailing the effects of stress in adults, for example, by brief treatment with antiglucocorticoids, may be beneficial to the treatment of epilepsy. [source]

    Stress for maintaining memory: HSP70 as a mobile messenger for innate and adaptive immunity

    Taoyong Chen
    Abstract HSP are abundant and conserved proteins present in all cells. Upon temperature shock or other stress stimuli, HSP are synthesized intracellularly, which may protect cells from protein denaturation or from death. Although HSP are synthesized intracellularly, HSP can also be mobilized to the plasma membrane or even be released under stress conditions. Elucidating the roles of cell surface and extracellular HSP in immune regulation has attracted much attention in recent years. Extracellularly, HSP can serve a cytokine function to initiate both innate and adaptive immunity through activation of APC. HSP serves also a chaperone function and facilitates presentation of antigen peptide to T cells. Similarly, cell surface HSP may activate APC and promote antigen presentation through cell,cell contact. A study in this issue of the European Journal of Immunology demonstrates that cell surface HSP70 on DC induced by stress can upregulate membrane-associated IL-15, which in turn promotes the proliferation of CD4+CD45RA memory T cells. Moreover, a DC-CD4+ T-cell interacting circuit formed by CD40L on T cells and CD40 on DC is proposed to play a role in the maintenance of memory homeostasis. This study has widened our view of HSP in adaptive immunity as well as their classical functions such as APC activator and antigen carrier. [source]

    New Approaches to 12-Coordination: Structural Consequences of Steric Stress, Lanthanoid Contraction and Hydrogen Bonding

    Anthony S. R. Chesman
    Abstract The anionic dinitrile ligand dicyanonitrosomethanide (dcnm), C(CN)2(NO),, and the anion resulting from its addition product with water, carbamoylcyanonitrosomethanide (ccnm), C(CN)(CONH2)(NO),, have been incorporated into lanthanoid complexes and display unusual ,2(N,O) nitroso coordination modes. (Et4N)3[Ln(ccnm)6] (1Ln; 1Ln = 1La, 1Ce, 1Pr, 1Nd, 1Sm) and (Me4N)3[Ln(ccnm)6] (2Ln; 2Ln = 2La, 2Ce, 2Pr, 2Nd) are systems containing 12-coordinate homoleptic trianionic lanthanoidate complexes. The nitroso groups of the ccnm ligands form three-membered ring chelates with the lanthanoid metal centre, with the asymmetry of the nitroso ,2 interactions dependent upon the intramolecular N,H···O=N hydrogen bonding. Additional intermolecular hydrogen bonding interactions exist between adjacent amide and nitrile groups giving rise to 3D ,-Po and 6,8-connected (412.63)(420.68) networks in 1Ln and 2Ln, respectively. The compounds (Me4N)3[Ln(dcnm)6] (3Ln; 3Ln = 3La, 3Ce, 3Nd, 3Sm) also contain a 12-coordinate trianionic lanthanoidate complex with the nitroso group exhibiting a highly symmetrical ,2 interaction. The sterically crowded environments of [Ln(18-crown-6)(dcnm)3] (4Ln; 4Ln = 4La, 4Ce, 4Pr, 4Nd) result in a shift towards a more asymmetric ,2 bonding of the nitroso group with decrease in the Ln3+ radius. There is a corresponding increase of the Ln,O,N angle, and one ligand is ,1(O) binding in 4Nd. The dcnm ligands in the discrete complexes [La(phen)3(dcnm)(3,x)Clx], x , 0.25 (5) (phen = 1,10-phenanthroline), (Et4N)[Ce(phen)2(dcnm)4] (6a/b, 6c) and [Ce(phen)2(dcnm)Cl2H2O] (7) display a variety of coordination modes. Complex 5 has 1D chains formed by ,,, stacking of adjacent phen co-ligands. Complexes 6 contain the monoanionic complex [Ce(phen)2(dcnm)4], with two geometric isomers present in the crystal structure of 6a/b. Complex 7 forms extended 1D chains via hydrogen bonding between coordinated water and chloride atoms and an extensive array of face-to-face , interactions. [source]

    REVIEW: Stress, alcohol and drug interaction: an update of human research

    ADDICTION BIOLOGY, Issue 1 2009
    Magdalena Uhart
    ABSTRACT A challenging question that continues unanswered in the field of addiction is why some individuals are more vulnerable to substance use disorders than others. Numerous risk factors for alcohol and other drugs of abuse, including exposure to various forms of stress, have been identified in clinical studies. However, the neurobiological mechanisms that underlie this relationship remain unclear. Critical neurotransmitters, hormones and neurobiological sites have been recognized, which may provide the substrates that convey individual differences in vulnerability to addiction. With the advent of more sophisticated measures of brain function in humans, such as functional imaging technology, the mechanisms and neural pathways involved in the interactions between drugs of abuse, the mesocorticolimbic dopamine system and stress systems are beginning to be characterized. This review provides a neuroadaptive perspective regarding the role of the hormonal and brain stress systems in drug addiction with a focus on the changes that occur during the transition from occasional drug use to drug dependence. We also review factors that contribute to different levels of hormonal/brain stress activation, which has implications for understanding individual vulnerability to drug dependence. Ultimately, these efforts may improve our chances of designing treatment strategies that target addiction at the core of the disorder. [source]

    REVIEW: Modeling stress and drug craving in the laboratory: implications for addiction treatment development

    ADDICTION BIOLOGY, Issue 1 2009
    Rajita Sinha
    ABSTRACT Addition is a chronic relapsing illness affected by multiple social, individual and biological factors that significantly impact course and recovery of the illness. Stress interacts with these factors and increases addiction vulnerability and relapse risk, thereby playing a significant role in the course of the illness. This paper reviews our efforts in developing and validating laboratory models of stress and drug cue-related provocation to assess stress responses and stress-related adaptation in addicted individuals compared with healthy controls. Empirical findings from human laboratory and brain imaging studies are presented to show the specific stress-related dysregulation that accompanies the drug-craving state in addicted individuals. In order to adequately validate our laboratory model, we have also carefully examined relapse susceptibility in the addicted individuals and these data are reviewed. The overarching goal of these efforts is to develop a valid laboratory model to identify the stress-related pathophysiology in addiction with specific regard to persistent craving and compulsive seeking. Finally, the significant implications of these findings for the development of novel treatment interventions that target stress processes and drug craving to improve addiction relapse outcomes are discussed. [source]

    Stress reverses plasticity in the pathway projecting from the ventromedial prefrontal cortex to the basolateral amygdala

    Mouna Maroun
    Abstract We have previously shown that high-frequency stimulation to the basolateral amygdala (BLA) induces long-term potentiation (LTP) in the ventromedial prefrontal cortex (vmPFC) and that prior exposure to inescapable stress inhibits the induction of LTP in this pathway [Maroun & Richter-Levin (2003)J. Neurosci., 23, 4406,4409]. Here, we show that the reciprocal pathway projecting from the vmPFC to the BLA is resistant to the induction of LTP. Conversely, long-term depression (LTD) is robustly induced in the BLA in response to low-frequency stimulation to the vmPFC. Furthermore, prior exposure to inescapable stress reverses plasticity in this pathway, resulting in the promotion of LTP and the inhibition of LTD. Our findings suggest that, under normal and safe conditions, the vmPFC is unable to exert excitatory synaptic plasticity over the BLA; rather, LTD, which encodes memory of safety in the BLA, is favoured. Following stressful experiences, LTP in the BLA is promoted to encode memory of fear. [source]