The Modulatory Properties of Chronic Antidepressant Drugs Treatment on the Brain Chemokine - Chemokine Receptor Network: A Molecular Study in an Animal Model of Depression.

PubMed

Trojan, Ewa; Ślusarczyk, Joanna; Chamera, Katarzyna; Kotarska, Katarzyna; Głombik, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka

2017-01-01

An increasing number of studies indicate that the chemokine system may be the third major communication system of the brain. Therefore, the role of the chemokine system in the development of brain disorders, including depression, has been recently proposed. However, little is known about the impact of the administration of various antidepressant drugs on the brain chemokine - chemokine receptor axis. In the present study, we used an animal model of depression based on the prenatal stress procedure. We determined whether chronic treatment with tianeptine, venlafaxine, or fluoxetine influenced the evoked by prenatal stress procedure changes in the mRNA and protein levels of the homeostatic chemokines, CXCL12 (SDF-1α), CX3CL1 (fractalkine) and their receptors, in the hippocampus and frontal cortex. Moreover, the impact of mentioned antidepressants on the TGF-β, a molecular pathway related to fractalkine receptor (CX3CR1), was explored. We found that prenatal stress caused anxiety and depressive-like disturbances in adult offspring rats, which were normalized by chronic antidepressant treatment. Furthermore, we showed the stress-evoked CXCL12 upregulation while CXCR4 downregulation in hippocampus and frontal cortex. CXCR7 expression was enhanced in frontal cortex but not hippocampus. Furthermore, the levels of CX3CL1 and CX3CR1 were diminished by prenatal stress in the both examined brain areas. The mentioned changes were normalized with various potency by chronic administration of tested antidepressants. All drugs in hippocampus, while tianeptine and venlafaxine in frontal cortex normalized the CXCL12 level in prenatally stressed offspring. Moreover, in hippocampus only fluoxetine enhanced CXCR4 level, while fluoxetine and tianeptine diminished CXCR7 level in frontal cortex. Additionally, the diminished by prenatal stress levels of CX3CL1 and CX3CR1 in the both examined brain areas were normalized by chronic tianeptine and partially fluoxetine administration. Tianeptine modulate also brain TGF-β signaling in the prenatal stress-induced animal model of depression. Our results provide new evidence that not only prenatal stress-induced behavioral disturbances but also changes of CXCL12 and their receptor and at less extend in CX3CL1-CX3CR1 expression may be normalized by chronic antidepressant drug treatment. In particular, the effect on the CXCL12 and their CXCR4 and CXCR7 receptors requires additional studies to elucidate the possible biological consequences.

Effects of prebiotic, protein level, and stocking density on performance, immunity, and stress indicators of broilers.

PubMed

Houshmand, M; Azhar, K; Zulkifli, I; Bejo, M H; Kamyab, A

2012-02-01

An experiment was conducted to determine the effects of period on the performance, immunity, and some stress indicators of broilers fed 2 levels of protein and stocked at a normal or high stocking density. Experimental treatments consisted of a 2 × 2 × 2 factorial arrangement with 2 levels of prebiotic (with or without prebiotic), 2 levels of dietary CP [NRC-recommended or low CP level (85% of NRC-recommended level)], and 2 levels of stocking density (10 birds/m(2) as the normal density or 16 birds/m(2) as the high density), for a total of 8 treatments. Each treatment had 5 replicates (cages). Birds were reared in 3-tiered battery cages with wire floors in an open-sided housing system under natural tropical conditions. Housing and general management practices were similar for all treatment groups. Starter and finisher diets in mash form were fed from 1 to 21 d and 22 to 42 d of age, respectively. Supplementation with a prebiotic had no significant effect on performance, immunity, and stress indicators (blood glucose, cholesterol, corticosterone, and heterophil:lymphocyte ratio). Protein level significantly influenced broiler performance but did not affect immunity or stress indicators (except for cholesterol level). The normal stocking density resulted in better FCR and also higher antibody titer against Newcastle disease compared with the high stocking density. However, density had no significant effect on blood levels of glucose, cholesterol, corticosterone, and the heterophil:lymphocyte ratio. Significant interactions between protein level and stocking density were observed for BW gain and final BW. The results indicated that, under the conditions of this experiment, dietary addition of a prebiotic had no significant effect on the performance, immunity, and stress indicators of broilers.

Natural thermal adaptation increases heat shock protein levels and decreases oxidative stress.

PubMed

Oksala, Niku K J; Ekmekçi, F Güler; Ozsoy, Ergi; Kirankaya, Serife; Kokkola, Tarja; Emecen, Güzin; Lappalainen, Jani; Kaarniranta, Kai; Atalay, Mustafa

2014-01-01

Heat shock proteins (HSPs), originally identified as heat-inducible gene products, are a family of highly conserved proteins that respond to a wide variety of stress including oxidative stress. Although both acute and chronic oxidative stress have been well demonstrated to induce HSP responses, little evidence is available whether increased HSP levels provide enhanced protection against oxidative stress under elevated yet sublethal temperatures. We studied relationships between oxidative stress and HSPs in a physiological model by using Garra rufa (doctor fish), a fish species naturally acclimatized to different thermal conditions. We compared fish naturally living in a hot spring with relatively high water temperature (34.4±0.6°C) to those living in normal river water temperature (25.4±4.7°C), and found that levels of all the studied HSPs (HSP70, HSP60, HSP90, HSC70 and GRP75) were higher in fish living in elevated water temperature compared with normal river water temperature. In contrast, indicators of oxidative stress, including protein carbonyls and lipid hydroperoxides, were decreased in fish living in the elevated temperature, indicating that HSP levels are inversely associated with oxidative stress. The present results provide evidence that physiologically increased HSP levels provide protection against oxidative stress and enhance cytoprotection. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Low-level laser therapy (LLLT) reduces oxidative stress in primary cortical neurons in vitro.

PubMed

Huang, Ying-Ying; Nagata, Kazuya; Tedford, Clark E; McCarthy, Thomas; Hamblin, Michael R

2013-10-01

Low-level laser (light) therapy (LLLT) involves absorption of photons being in the mitochondria of cells leading to improvement in electron transport, increased mitochondrial membrane potential (MMP), and greater ATP production. Low levels of reactive oxygen species (ROS) are produced by LLLT in normal cells that are beneficial. We exposed primary cultured murine cortical neurons to oxidative stressors: hydrogen peroxide, cobalt chloride and rotenone in the presence or absence of LLLT (3 J/cm², CW, 810 nm wavelength laser, 20 mW/cm²). Cell viability was determined by Prestoblue™ assay. ROS in mitochondria was detected using Mito-sox, while ROS in cytoplasm was detected with CellRox™. MMP was measured with tetramethylrhodamine. In normal neurons LLLT elevated MMP and increased ROS. In oxidatively-stressed cells LLLT increased MMP but reduced high ROS levels and protected cultured cortical neurons from death. Although LLLT increases ROS in normal neurons, it reduces ROS in oxidatively-stressed neurons. In both cases MMP is increased. These data may explain how LLLT can reduce clinical oxidative stress in various lesions while increasing ROS in cells in vitro. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cold hardiness in relation to trace metal stress in the freeze-avoiding beetle Tenebrio molitor.

PubMed

Pedersen, Sindre A; Kristiansen, Erlend; Hansen, Bjørn H; Andersen, Rolf A; Zachariassen, Karl E

2006-08-01

The antifreeze proteins (AFPs) are a family of proteins characterised by their ability to inhibit the growth of ice. These proteins have evolved as a protection against lethal freezing in freeze avoiding species. Metal stress has been shown to reduce the cold hardening in invertebrates, but no study has investigated how this type of stress affects the production of AFPs. This study demonstrates that exposure to cadmium (Cd), copper (Cu) and zinc (Zn) reduces the normal developmental increase in AFP levels in Tenebrio molitor larvae reared under summer conditions. Exposure to winter conditions, however stimulated the production of AFPs in the metal exposed larvae, and raised the concentrations of AFPs to normal winter levels. The reduced level of AFPs in metal-stressed animals acclimated to summer conditions seems to arise from alterations in the normal gene expression of AFPs. The results indicate that metal exposure may cause freeze avoiding insects to become more susceptible to lethal freezing, as they enter the winter with lowered levels of AFPs. Such an effect cannot be revealed by ordinary toxicological tests, but may nevertheless be of considerable ecological importance.

5,7-Dimethoxycoumarin prevents chronic mild stress induced depression in rats through increase in the expression of heat shock protein-70 and inhibition of monoamine oxidase-A levels.

PubMed

Yang, Wei; Wang, Huanlin

2018-02-01

The current study was aimed to investigate the role of 5,7-dimethoxycoumarin in the prevention of chronic mild stress induced depression in rats. The chronic mild stress rat model was prepared using the known protocols. The results from open-field test showed that rats in the chronic mild stress group scored very low in terms of crossings and rearings than those of the normal rats. However, pre-treatment of the rats with 10 mg/kg doses of 5,7-dimethoxycoumarin prevented decline in the locomotor activity by chronic mild stress. The level of monoamine oxidase-A in the chronic mild stress rat hippocampus was markedly higher. Chronic mild stress induced increase in the monoamine oxidase-A level was inhibited by pre-treatment with 10 mg/kg doses of 5,7-dimethoxycoumarin in the rats. Chronic mild stress caused a marked increase in the level of caspase-3 mRNA and proteins in rat hippocampus tissues. The increased level of caspase-3 mRNA and protein level was inhibited by treatment of rats with 5,7-dimethoxycoumarin (10 mg/kg). 5,7-Dimethoxycoumarin administration into the rats caused a marked increase in the levels of heat shock protein-70 mRNA and protein. The levels of heat shock protein-70 were markedly lower both in normal and chronic mild stress groups of rats compared to the 5,7-dimethoxycoumarin treated groups. Thus 5,7-dimethoxycoumarin prevented the chronic mild stress induced depression in rats through an increase in the expression of heat shock protein-70 and inhibition of monoamine oxidase-A levels.

Characterization of the Differential Response of Endothelial Cells Exposed to Normal and Elevated Laminar Shear Stress

PubMed Central

White, Stephen J; Hayes, Elaine M; Lehoux, Stéphanie; Jeremy, Jamie Y; Horrevoets, Anton JG; Newby, Andrew C

2011-01-01

Most acute coronary events occur in the upstream region of stenotic atherosclerotic plaques that experience laminar shear stress (LSS) elevated above normal physiological levels. Many studies have described the atheroprotective effect on endothelial behavior of normal physiological LSS (approximately 15 dynes/cm2) compared to static or oscillatory shear stress (OSS), but it is unknown whether the levels of elevated shear stress imposed by a stenotic plaque would preserve, enhance or reverse this effect. Therefore we used transcriptomics and related functional analyses to compare human endothelial cells exposed to laminar shear stress of 15 (LSS15-normal) or 75 dynes/cm2 (LSS75-elevated). LSS75 upregulated expression of 145 and downregulated expression of 158 genes more than twofold relative to LSS15. Modulation of the metallothioneins (MT1-G, -M, -X) and NADPH oxidase subunits (NOX2, NOX4, NOX5, and p67phox) accompanied suppression of reactive oxygen species production at LSS75. Shear induced changes in dual specificity phosphatases (DUSPs 1, 5, 8, and 16 increasing and DUSPs 6 and 23 decreasing) were observed as well as reduced ERK1/2 but increased p38 MAP kinase phosphorylation. Amongst vasoactive substances, endothelin-1 expression decreased whereas vasoactive intestinal peptide (VIP) and prostacyclin expression increased, despite which intracellular cAMP levels were reduced. Promoter analysis by rVISTA identified a significant over representation of ATF and Nrf2 transcription factor binding sites in genes upregulated by LSS75 compared to LSS15. In summary, LSS75 induced a specific change in behavior, modifying gene expression, reducing ROS levels, altering MAP kinase signaling and reducing cAMP levels, opening multiple avenues for future study. J. Cell. Physiol. 226: 2841–2848, 2011. © 2011 Wiley-Liss, Inc. PMID:21302282

Characterization of the differential response of endothelial cells exposed to normal and elevated laminar shear stress.

PubMed

White, Stephen J; Hayes, Elaine M; Lehoux, Stéphanie; Jeremy, Jamie Y; Horrevoets, Anton J G; Newby, Andrew C

2011-11-01

Most acute coronary events occur in the upstream region of stenotic atherosclerotic plaques that experience laminar shear stress (LSS) elevated above normal physiological levels. Many studies have described the atheroprotective effect on endothelial behavior of normal physiological LSS (approximately 15 dynes/cm(2)) compared to static or oscillatory shear stress (OSS), but it is unknown whether the levels of elevated shear stress imposed by a stenotic plaque would preserve, enhance or reverse this effect. Therefore we used transcriptomics and related functional analyses to compare human endothelial cells exposed to laminar shear stress of 15 (LSS15-normal) or 75 dynes/cm(2) (LSS75-elevated). LSS75 upregulated expression of 145 and downregulated expression of 158 genes more than twofold relative to LSS15. Modulation of the metallothioneins (MT1-G, -M, -X) and NADPH oxidase subunits (NOX2, NOX4, NOX5, and p67phox) accompanied suppression of reactive oxygen species production at LSS75. Shear induced changes in dual specificity phosphatases (DUSPs 1, 5, 8, and 16 increasing and DUSPs 6 and 23 decreasing) were observed as well as reduced ERK1/2 but increased p38 MAP kinase phosphorylation. Amongst vasoactive substances, endothelin-1 expression decreased whereas vasoactive intestinal peptide (VIP) and prostacyclin expression increased, despite which intracellular cAMP levels were reduced. Promoter analysis by rVISTA identified a significant over representation of ATF and Nrf2 transcription factor binding sites in genes upregulated by LSS75 compared to LSS15. In summary, LSS75 induced a specific change in behavior, modifying gene expression, reducing ROS levels, altering MAP kinase signaling and reducing cAMP levels, opening multiple avenues for future study. Copyright © 2011 Wiley-Liss, Inc.

Stress inhibits PYY secretion in obese and normal weight women.

PubMed

Kiessl, Gundula R R; Laessle, Reinhold G

2016-06-01

The impact of stress on circulating levels of appetite-regulating hormones remains largely unknown. The aim of this study was to analyze the effect of acute psychosocial stress on the gut hormone peptide YY (PYY) secretion in obese and normal weight women. Therefore, we compared pre- and post-prandial plasma PYY secretion of 42 obese and 43 normal weight women in a repeated measure randomized controlled laboratory experiment. PYY and cortisol concentrations were measured and ratings of stress and satiety were also recorded in response to a psychological stressor (Trier Social Stress Test, TSST). PYY samples were collected in the fasting state both before participating in the TSST and before a control session. Participants had a standardized meal after the TSST and control session, respectively. PYY was measured both 30 and 60 min after the TSST and control session, respectively. Stress inhibited PYY secretion as well as food intake in all women, but did not influence subjective satiety perception. The present data indicate that despite of lower PYY levels the subjects' requirement to overeat was not increased. From an evolutionary perspective this finding is adaptive. After stress the organism is prepared for fight or flight reaction, whereas not primarily necessary functions are inhibited. Therefore, increased food intake during stress would be dysfunctional.

Salt-tolerant and -sensitive alfalfa (Medicago sativa) cultivars have large variations in defense responses to the lepidopteran insect Spodoptera litura under normal and salt stress condition

PubMed Central

Lei, Yunting; Liu, Qing; Hettenhausen, Christian; Cao, Guoyan; Tan, Qing; Zhao, Weiye; Lin, Honghui

2017-01-01

In nature, plants are often exposed to multiple stress factors at the same time. Yet, little is known about how plants modulate their physiology to counteract simultaneous abiotic and biotic stresses, such as soil salinity and insect herbivory. In this study, insect performance bioassays, phytohormone measurements, quantification of transcripts, and protein determination were employed to study the phenotypic variations of two alfalfa (Medicago sativa) cultivars in response to insect Spodoptera litura feeding under normal and salt stress condition. When being cultivated in normal soil, the salt-tolerant alfalfa cultivar Zhongmu-1 exhibited lower insect resistance than did the salt-sensitive cultivar Xinjiang Daye. Under salinity stress, the defense responses of Xinjiang Daye were repressed, whereas Zhongmu-1 did not show changes in resistance levels. It is likely that salinity influenced the resistance of Xinjiang Daye through suppressing the accumulation of jasmonic acid-isoleucine (JA-Ile), which is the bioactive hormone inducing herbivore defense responses, leading to attenuated trypsin proteinase inhibitor (TPI) activity. Furthermore, exogenous ABA supplementation suppressed the insect herbivory-induced JA/JA-Ile accumulation and levels of JAR1 (jasmonate resistant 1) and TPI, and further decreased the resistance of Xinjiang Daye, whereas Zhongmu-1 showed very little response to the increased ABA level. We propose a mechanism, in which high levels of abscisic acid induced by salt treatment may affect the expression levels of JAR1 and consequently decrease JA-Ile accumulation and thus partly suppress the defense of Xinjiang Daye against insects under salt stress. This study provides new insight into the mechanism by which alfalfa responds to concurrent abiotic and biotic stresses. PMID:28719628

Salt-tolerant and -sensitive alfalfa (Medicago sativa) cultivars have large variations in defense responses to the lepidopteran insect Spodoptera litura under normal and salt stress condition.

PubMed

Lei, Yunting; Liu, Qing; Hettenhausen, Christian; Cao, Guoyan; Tan, Qing; Zhao, Weiye; Lin, Honghui; Wu, Jianqiang

2017-01-01

In nature, plants are often exposed to multiple stress factors at the same time. Yet, little is known about how plants modulate their physiology to counteract simultaneous abiotic and biotic stresses, such as soil salinity and insect herbivory. In this study, insect performance bioassays, phytohormone measurements, quantification of transcripts, and protein determination were employed to study the phenotypic variations of two alfalfa (Medicago sativa) cultivars in response to insect Spodoptera litura feeding under normal and salt stress condition. When being cultivated in normal soil, the salt-tolerant alfalfa cultivar Zhongmu-1 exhibited lower insect resistance than did the salt-sensitive cultivar Xinjiang Daye. Under salinity stress, the defense responses of Xinjiang Daye were repressed, whereas Zhongmu-1 did not show changes in resistance levels. It is likely that salinity influenced the resistance of Xinjiang Daye through suppressing the accumulation of jasmonic acid-isoleucine (JA-Ile), which is the bioactive hormone inducing herbivore defense responses, leading to attenuated trypsin proteinase inhibitor (TPI) activity. Furthermore, exogenous ABA supplementation suppressed the insect herbivory-induced JA/JA-Ile accumulation and levels of JAR1 (jasmonate resistant 1) and TPI, and further decreased the resistance of Xinjiang Daye, whereas Zhongmu-1 showed very little response to the increased ABA level. We propose a mechanism, in which high levels of abscisic acid induced by salt treatment may affect the expression levels of JAR1 and consequently decrease JA-Ile accumulation and thus partly suppress the defense of Xinjiang Daye against insects under salt stress. This study provides new insight into the mechanism by which alfalfa responds to concurrent abiotic and biotic stresses.

Direct Shear Tests of Sandstone Under Constant Normal Tensile Stress Condition Using a Simple Auxiliary Device

NASA Astrophysics Data System (ADS)

Cen, Duofeng; Huang, Da

2017-06-01

Tension-shear failure is a typical failure mode in the rock masses in unloading zones induced by excavation or river incision, etc., such as in excavation-disturbed zone of deep underground caverns and superficial rocks of high steep slopes. However, almost all the current shear failure criteria for rock are usually derived on the basis of compression-shear failure. This paper proposes a simple device for use with a servo-controlled compression-shear testing machine to conduct the tension-shear tests of cuboid rock specimens, to test the direct shear behavior of sandstone under different constant normal tensile stress conditions ( σ = -1, -1.5, -2, -2.5 and -3 MPa) as well as the uniaxial tension behavior. Generally, the fracture surface roughness decreases and the proportion of comminution areas in fracture surface increases as the change of stress state from tension to tension-shear and to compression-shear. Stepped fracture is a primary fracture pattern in the tension-shear tests. The shear stiffness, shear deformation and normal deformation (except the normal deformation for σ = -1 MPa) decrease during shearing, while the total normal deformation containing the pre-shearing portion increases as the normal tensile stress level (| σ|) goes up. Shear strength is more sensitive to the normal tensile stress than to the normal compressive stress, and the power function failure criterion (or Mohr envelope form of Hoek-Brown criterion) is examined to be the optimal criterion for the tested sandstone in the full region of tested normal stress in this study.

Increased plasma peroxides as a marker of oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

PubMed

Maes, Michael; Kubera, Marta; Uytterhoeven, Marc; Vrydags, Nicolas; Bosmans, Eugene

2011-04-01

There is evidence that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by activation of immune, inflammatory, oxidative and nitrosative stress (IO&NS) pathways. The present study was carried out in order to examine whether ME/CFS is accompanied by increased levels of plasma peroxides and serum oxidized LDL (oxLDL) antibodies, two biomarkers of oxidative stress. Blood was collected from 56 patients with ME/CFS and 37 normal volunteers. Severity of ME/CFS was measured using the Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale. Plasma peroxide concentrations were significantly higher in patients with ME/CFS than in normal controls. There was a trend towards significantly higher serum oxLDL antibodies in ME/CFS than in controls. Both biomarkers contributed significantly in discriminating between patients with ME/CFS and normal controls. Plasma peroxide and serum oxLDL antibody levels were both significantly related to one of the FF symptoms. The results show that ME/CFS is characterized by increased oxidative stress.

Blood glucose may condition factor VII levels in diabetic and normal subjects.

PubMed

Ceriello, A; Giugliano, D; Quatraro, A; Dello Russo, P; Torella, R

1988-12-01

Increased factor VII levels have been reported in Type 1 (insulin-dependent) diabetic subjects. A direct correlation between fasting plasma glucose and factor VII level was found to exist in both diabetic and normal subjects. Induced-hyperglycaemia was able to increase factor VII levels in both diabetic patients and normal control subjects while, when euglycaemia was achieved in diabetic patients, factor VII values returned to normal range. This study shows that the level of factor VII may be directly conditioned by circulating blood glucose and, therefore, stresses the role of hyperglycaemia in conditioning coagulation abnormalities in diabetes mellitus.

Differing patterns of stress and craving across the day in moderate-heavy alcohol consumers during their typical drinking routine and an imposed period of alcohol abstinence.

PubMed

Mayhugh, Rhiannon E; Rejeski, W Jack; Petrie, Meredith R; Laurienti, Paul J; Gauvin, Lise

2018-01-01

Stress is a known factor related to alcohol use. However, how the relationship between alcohol craving and stress varies across the day is not fully understood. As craving is a consistent predictor of alcohol use disorder (AUD), understanding stress and craving patterns across the day in routine, non-dependent, moderate-heavy alcohol consumers may help in understanding those who may be vulnerable to transitioning into AUD. Moderate-heavy drinkers were recruited from the local community (n = 32) and assessed for fluctuations in craving and stress intensity across the day via Ecological Momentary Assessment (EMA) during 3 consecutive days of imposed alcohol abstinence (abstained trial) and their normal drinking routine (normal trial). A multilevel modeling statistical approach assessed differences in diurnal craving and stress patterns with the Alcohol Craving Experience Questionnaire (ACE) examined as a moderator. Immediately following alcohol consumption on normal trials, EMA craving levels were significantly reduced compared to pre-drinking levels. Moreover, the post-drinking craving levels were lower than on abstained trials. Higher ACE scores were associated with significantly higher EMA craving across the day and higher peaks at midday. Higher ACE scores were also associated with greater EMA stress across the day. Drinking relieved stress relative to abstained trials, but not in individuals with higher ACE scores. Higher stress was associated with greater EMA craving, which was stronger among those with higher ACE scores. These findings suggest that ACE scores are important to understanding patterns of stress and craving experienced across the day in routine, non-dependent, moderate-heavy drinkers and may provide new insights for vulnerability to transitioning into AUD.

Effect of psychological stress on fertility hormones and seminal quality in male partners of infertile couples.

PubMed

Bhongade, M B; Prasad, S; Jiloha, R C; Ray, P C; Mohapatra, S; Koner, B C

2015-04-01

The present study evaluated the effect of psychological stress on male fertility hormones and seminal quality in male partner of infertile couples. Seventy male partners of infertile couples were evaluated for level of psychological stress using Hospital Anxiety and Depression Score (HADS) questionnaire, serum total testosterone, luteinising hormone (LH) and follicle-stimulating hormone (FSH) by electrochemiluminescence assay and serum GnRH by ELISA. Seminal analysis was performed as per WHO guideline. Nineteen (27%) of them had HADS anxiety and depression score ≥8 (abnormal HADS score). The persons having abnormal HADS had lower serum total testosterone, higher serum FSH and LH than those of persons having normal HADS. Serum total testosterone correlated negatively with HADS, but LH and FSH correlated positively. There was no change in GnRH with the change in stress or testosterone levels. Sperm count, motility and morphologically normal spermatozoa were lower in persons having abnormal HADS. Sperm count correlated positively with total testosterone and negatively with FSH and LH. Abnormal sperm motility and morphology were related to lower testosterone and higher LH and FSH levels. Psychological stress primarily lowers serum total testosterone level with secondary rise in serum LH and FSH levels altering seminal quality. Stress management is warranted for male infertility cases. © 2014 Blackwell Verlag GmbH.

Resveratrol alleviates diabetes-induced testicular dysfunction by inhibiting oxidative stress and c-Jun N-terminal kinase signaling in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faid, Iman; Al-Hussaini, Heba; Kilarkaje, Narayana, E-mail: knarayana@hsc.edu.kw

Diabetes adversely affects reproductive functions in humans and animals. The present study investigated the effects of Resveratrol on diabetes-induced alterations in oxidative stress, c-Jun N-terminal kinase (JNK) signaling and apoptosis in the testis. Adult male Wistar rats (13–15 weeks; n = 6/group) were segregated into 1) normal control, 2) Resveratrol-treated (5 mg/kg; ip; given during last 3 weeks), 3) Streptozotocin-induced diabetic and, 4) Resveratrol-treated diabetic groups, and euthanized on day 42 after the confirmation of diabetes. Resveratrol did not normalize blood glucose levels in diabetic rats. Resveratrol supplementation recovered diabetes-induced decreases in reproductive organ weights, sperm count and motility, intra-testicularmore » levels of superoxide dismutase, catalase, and glutathione peroxidase and an increase in 4-hydroxynonenal activities (P < 0.05). Resveratrol also recovered diabetes-induced increases in JNK signaling pathway proteins, namely, ASK1 (apoptosis signal-regulating kinase 1), JNKs (46 and 54 kDa isoforms) and p-JNK to normal control levels (P < 0.05). Interestingly, the expression of a down-stream target of ASK1, MKK4 (mitogen-activated protein kinase kinase 4) and its phosphorylated form (p-MKK4) did not change in experimental groups. Resveratrol inhibited diabetes-induced increases in AP-1 (activator protein-1) components, c-Jun and ATF2 (activating transcription factor 2), but not their phosphorylated forms, to normal control levels (P < 0.05). Further, Resveratrol inhibited diabetes-induced increase in cleaved-caspase-3 to normal control levels. In conclusion, Resveratrol alleviates diabetes-induced apoptosis in testis by modulating oxidative stress, JNK signaling pathway and caspase-3 activities, but not by inhibiting hyperglycemia, in rats. These results suggest that Resveratrol supplementation may be a useful strategy to treat diabetes-induced testicular dysfunction. - Highlights: • Resveratrol up-regulates glutathione peroxidase and catalase levels in the testis. • Diabetes up-regulates oxidative stress and JNK pathway in the testis. • Resveratrol inhibits diabetes-induced oxidative stress and JNK pathway. • Resveratrol mitigates diabetes-induced apoptosis of testicular cells. • Resveratrol treatment alleviates diabetes-induced testicular dysfunction.« less

Alpha-mangostin attenuates diabetic nephropathy in association with suppression of acid sphingomyelianse and endoplasmic reticulum stress.

PubMed

Liu, Tingting; Duan, Wang; Nizigiyimana, Paul; Gao, Lin; Liao, Zhouning; Xu, Boya; Liu, Lerong; Lei, Minxiang

2018-02-05

Diabetic nephropathy is a common complication of diabetes, but there are currently few treatment options. The aim of this study was to gain insight into the effect of alpha-mangostin on diabetic nephropathy and possible related mechanisms. Goto-Kakizaki rats were used as a diabetic model and received alpha-mangostin or desipramine treatment with normal saline as a control. Ten age-matched Sprague Dawley rats were used as normal controls and treated with normal saline. At week 12, blood glucose, albuminuria, apoptosis and renal pathologic changes were assessed. Protein levels for acid sphingomyelinase, glucose-regulated protein 78, phosphorylated PKR-like ER-resident kinase, activated transcription factor 4, CCAAT/enhancer-binding protein, homologous protein), and cleaved-caspase12 were measured. The level of acid sphingomyelinase was significantly increased, and ER stress was activated in diabetic rat kidneys when compared to the control animals. When acid sphingomyelinase was inhibited by alpha-mangostin, the expression of ER stress-related proteins was down-regulated in association with decreased levels of diabetic kidney injury. Alpha-mangostin, an acid sphingomyelinase inhibitor plays a protective role in diabetic neuropathy by relieving ER stress induced-renal cell apoptosis. Copyright © 2018 Elsevier Inc. All rights reserved.

Protective effect of catechin in type I Gaucher disease cells by reducing endoplasmic reticulum stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Yea-Jin; Kim, Sung-Jo, E-mail: sungjo@hoseo.edu; Heo, Tae-Hwe, E-mail: thhur92@catholic.ac.kr

Highlights: {yields} Catechin reduces the expression level of ER stress marker protein in type I Gaucher disease cells. {yields} Catechin induces the proliferation rate of GD cells similar levels to normal cells. {yields} Catechin improves wound healing activity. {yields} Catechin-mediated reductions in ER stress may be associated with enhanced cell survival. {yields} We identified catechin as a protective agent against ER stress in GD cells. -- Abstract: Gaucher disease (GD) is the most common lysosomal storage disorder (LSD) and is divided into three phenotypes, I, II, and III. Type I is the most prevalent form and has its onset inmore » adulthood. The degree of endoplasmic reticulum (ER) stress is one of the factors that determine GD severity. It has recently been reported that antioxidants reduce ER stress and apoptosis by scavenging the oxidants that cause oxidative stress. For this report, we investigated the possibility that catechin can act on type I GD patient cells to alleviate the pathogenic conditions of GD. We treated GD cells with catechin and examined the expression level of GRP78/BiP (an ER stress marker) by western blots and fluorescence microscopy, the proliferation rate of GD cells, and scratch-induced wound healing activity. Our results show that catechin reduces the expression level of GRP78/BiP, leads to cell proliferation rates of GD cells similar levels to normal cells, and improves wound healing activity. We conclude that catechin protects against ER stress in GD cells and catechin-mediated reductions in ER stress may be associated with enhanced cell survival.« less

Cardiac damage associated with stress hyperglycaemia and acute coronary syndrome changes according to level of presenting blood glucose.

PubMed

Al Jumaily, Talib; Rose'Meyer, Roselyn B; Sweeny, Amy; Jayasinghe, Rohan

2015-10-01

To determine the prevalence of stress hyperglycaemia in people presenting with acute coronary syndrome (ACS), and the relationships between admission glucose and cardiac damage, cardiovascular mortality and morbidity. In a prospective observational study people presenting with ACS at the Gold Coast Hospital had their admission glucose (AG) level tested to determine stress hyperglycaemia. A range of measurements supplemented this data including troponin levels, category of ACS and major adverse coronary events (MACEs) were obtained through hospital records and patient follow-up post-discharge. One hundred eighty-eight participants were recruited. The prevalence of stress hyperglycaemia in ACS was 44% with 31% having a previous diagnosis of type 2 diabetes and 7.7% had undiagnosed diabetes. The stress hyperglycaemic group had a significantly higher median troponin levels compared to participants with normal blood glucose levels on admission (p<0.05) however the highest presenting glucose group (>15 mmol/L) had troponin levels similar to people presenting with normal blood glucose levels and ACS (p>0.05). Cardiac necrosis as measured by troponin levels is significantly increased in people with ACS and stress hyperglycaemia. This study found that one in four participants presenting with ACS and an admission glucose of >7.0 had no previous diagnosis for diabetes. Consistently ordering HbA1C testing on patients with high AG can enable earlier diagnosis and treatment of diabetes. Copyright © 2015. Published by Elsevier Ireland Ltd.

Stress-induced ascorbic acid depletion and cortisol production in two salmonid fishes

USGS Publications Warehouse

Wedemeyer, Gary

1969-01-01

Interrenal ascorbic acid and serum cortisol were measured in non-specificity stressed yearling coho salmon and rainbow trout.Interrenal ascorbate was markedly decreased during stress but increased to normal if adaptation occurred.Serum cortisol was elevated by non-specific stress and remained high after interrenal ascorbate had returned to initial levels.

Dynamic release and clearance of circulating microparticles during cardiac stress.

PubMed

Augustine, Daniel; Ayers, Lisa V; Lima, Eduardo; Newton, Laura; Lewandowski, Adam J; Davis, Esther F; Ferry, Berne; Leeson, Paul

2014-01-03

Microparticles are cell-derived membrane vesicles, relevant to a range of biological responses and known to be elevated in cardiovascular disease. To investigate microparticle release during cardiac stress and how this response differs in those with vascular disease. We measured a comprehensive panel of circulating cell-derived microparticles by a standardized flow cytometric protocol in 119 patients referred for stress echocardiography. Procoagulant, platelet, erythrocyte, and endothelial but not leukocyte, granulocyte, or monocyte-derived microparticles were elevated immediately after a standardized dobutamine stress echocardiogram and decreased after 1 hour. Twenty-five patients developed stress-induced wall motion abnormalities suggestive of myocardial ischemia. They had similar baseline microparticle levels to those who did not develop ischemia, but, interestingly, their microparticle levels did not change during stress. Furthermore, no stress-induced increase was observed in those without inducible ischemia but with a history of vascular disease. Fourteen patients subsequently underwent coronary angiography. A microparticle rise during stress echocardiography had occurred only in those with normal coronary arteries. Procoagulant, platelet, erythrocyte, and endothelial microparticles are released during cardiac stress and then clear from the circulation during the next hour. This stress-induced rise seems to be a normal physiological response that is diminished in those with vascular disease.

Ectopic expression of ABSCISIC ACID 2/GLUCOSE INSENSITIVE 1 in Arabidopsis promotes seed dormancy and stress tolerance.

PubMed

Lin, Pei-Chi; Hwang, San-Gwang; Endo, Akira; Okamoto, Masanori; Koshiba, Tomokazu; Cheng, Wan-Hsing

2007-02-01

Abscisic acid (ABA) is an important phytohormone that plays a critical role in seed development, dormancy, and stress tolerance. 9-cis-Epoxycarotenoid dioxygenase is the key enzyme controlling ABA biosynthesis and stress tolerance. In this study, we investigated the effect of ectopic expression of another ABA biosynthesis gene, ABA2 (or GLUCOSE INSENSITIVE 1 [GIN1]) encoding a short-chain dehydrogenase/reductase in Arabidopsis (Arabidopsis thaliana). We show that ABA2-overexpressing transgenic plants with elevated ABA levels exhibited seed germination delay and more tolerance to salinity than wild type when grown on agar plates and/or in soil. However, the germination delay was abolished in transgenic plants showing ABA levels over 2-fold higher than that of wild type grown on 250 mm NaCl. The data suggest that there are distinct mechanisms underlying ABA-mediated inhibition of seed germination under diverse stress. The ABA-deficient mutant aba2, with a shorter primary root, can be restored to normal root growth by exogenous application of ABA, whereas transgenic plants overexpressing ABA2 showed normal root growth. The data reflect that the basal levels of ABA are essential for maintaining normal primary root elongation. Furthermore, analysis of ABA2 promoter activity with ABA2::beta-glucuronidase transgenic plants revealed that the promoter activity was enhanced by multiple prolonged stresses, such as drought, salinity, cold, and flooding, but not by short-term stress treatments. Coincidently, prolonged drought stress treatment led to the up-regulation of ABA biosynthetic and sugar-related genes. Thus, the data support ABA2 as a late expression gene that might have a fine-tuning function in mediating ABA biosynthesis through primary metabolic changes in response to stress.

Perceived Support as a Predictor of Acculturative Stress among International Students in the United States

ERIC Educational Resources Information Center

Bai, Jieru

2016-01-01

A quantitative study was conducted to measure the acculturative stress of international students and investigate the predictors of acculturative stress. A total of 186 students participated in the survey. Results showed that 22.4% of the students in this study exceeded the normal stress level and might need counseling or psychological…

Behaviour problems and cortisol levels in very-low-birth-weight children.

PubMed

Wadsby, Marie; Nelson, Nina; Ingemansson, Fredrik; Samuelsson, Stefan; Leijon, Ingemar

2014-11-01

Abstract Background. There are still diverging results concerning the behaviour of children with very-low-birth-weight (VLBW) and they have been questioned to display different levels of stress hormone than normal-birth-weight (NBW) children. Aims. This study examined behaviour and the stress hormone cortisol in children with VLBW at the ages of 7 and 9 years compared with children with NBW. Results. Fifty-one VLBW and 50 NBW children were studied with the Child Behavior Checklist. Cortisol rhythm was measured through saliva samples three times a day for 2 days. VLBW children displayed more behavioural problems than NBW children, specifically social and attention problems, although still within normal ranges. They showed lower cortisol levels both at 7 and 9 years of age. No strong association between behaviour and cortisol levels was shown. Conclusion. VLBW children display more behaviour problems compared with NBW children but both groups score are within the normal range. Down-regulation of their hypothalamic-pituitary-adrenal (HPA) function in terms of lower cortisol levels is also noted.

Effects of Lentinula edodes consumption on biochemical, hematologic and oxidative stress parameters in rats receiving high-fat diet.

PubMed

Spim, Sara Rosicler Vieira; de Oliveira, Bruna Giovanna Corrêa Chrispim; Leite, Fernanda Gomes; Gerenutti, Marli; Grotto, Denise

2017-10-01

Functional foods can prevent/reduce the risks related to obesity. Lentinula edodes is a highly nutritious mushroom rich in protein, vitamins and minerals. Some studies have demonstrated the hypocholesterolemic effects from L. edodes in high doses, which does not represent the consumption in humans. We evaluated ingestion of a realistic dose of L. edodes associated with a high-fat diet (HFD) on hematologic, biochemical and oxidative stress parameters. Eighteen male Wistar rats were divided into three groups: control (normal diet); HFD; and HFD + L. edodes (100 mg/kg/day). After 30 days, blood was collected. Biochemical and hematologic parameters were analyzed, as well as oxidative stress biomarkers. The HFD increased levels of total cholesterol and triglycerides. Lentinula edodes reduced these parameters significantly to concentrations found in the control group. The HFD increased levels of alanine transaminase and aspartate transaminase (markers of liver damage). Lentinula edodes returned the levels of these enzymes to normal levels and normalized serum levels of urea (which were also increased owing to consumption of the HFD). Lentinula edodes reduced levels of urea and glucose. Lipid peroxidation was increased in rats receiving the HFD, and L. edodes reduced malondialdehyde levels, thereby preventing oxidation of fatty acids. Lentinula edodes was shown to have hypolipidemic, hypoglycemic, hepatoprotective and renoprotective features in doses that are suitable for humans.

Evaluation and selection of reliable reference genes for gene expression under abiotic stress in cotton (Gossypium hirsutum L.).

PubMed

Wang, Min; Wang, Qinglian; Zhang, Baohong

2013-11-01

Reference genes are critical for normalization of the gene expression level of target genes. The widely used housekeeping genes may change their expression levels at different tissue under different treatment or stress conditions. Therefore, systematical evaluation on the housekeeping genes is required for gene expression analysis. Up to date, no work was performed to evaluate the housekeeping genes in cotton under stress treatment. In this study, we chose 10 housekeeping genes to systematically assess their expression levels at two different tissues (leaves and roots) under two different abiotic stresses (salt and drought) with three different concentrations. Our results show that there is no best reference gene for all tissues at all stress conditions. The reliable reference gene should be selected based on a specific condition. For example, under salt stress, UBQ7, GAPDH and EF1A8 are better reference genes in leaves; TUA10, UBQ7, CYP1, GAPDH and EF1A8 were better in roots. Under drought stress, UBQ7, EF1A8, TUA10, and GAPDH showed less variety of expression level in leaves and roots. Thus, it is better to identify reliable reference genes first before performing any gene expression analysis. However, using a combination of housekeeping genes as reference gene may provide a new strategy for normalization of gene expression. In this study, we found that combination of four housekeeping genes worked well as reference genes under all the stress conditions. © 2013.

Relationship between general intelligence, emotional intelligence, stress levels and stress reactivity.

PubMed

Singh, Yogesh; Sharma, Ratna

2012-07-01

Stressful life events and daily life stresses have both deleterious and cumulative effects on human body. In several studies, stress has been shown to affect various parameter of higher mental function like attention, concentration, learning and memory. Present study was designed to explore the relationship among GI level, EI level, psychological stress levels and acute stress reactivity in young normal healthy subjects. The study was conducted on thirty four healthy male student volunteers to study a) acute stress reactivity in subjects with varying levels of General Intelligence (GI) and Emotional Intelligence (EI) and b) correlation between GI, EI, acute stress and perceived stress. Baseline GI and EI and acute stress and perceived stress scores were measured by standard assessment scales. Using median value of GI and EI scores as cutoff values, subjects were categorized into four groups. Among different GI-EI groups, acute stress reactivity was similar but salivary Cortisol (especially post stressor level) and perceived stress level was a differentiating factor. High level of EI was associated inversely with acute and chronic perceived stress level. Significant correlation was found between acute and chronic perceived stress levels. Level of general intelligence showed no relation to acute or chronic stress levels as well as acute stress reactivity. The differences in various groups of GI and EI had no effect on the baseline and post stress performance on Sternberg memory test and all the three conditions of Stroop test. In conclusion emotional intelligence as an attribute is better suited to handle day to day acute stress and chronic perceived stress.

Hormonal treatment reduces psychobiological distress in gender identity disorder, independently of the attachment style.

PubMed

Colizzi, Marco; Costa, Rosalia; Pace, Valeria; Todarello, Orlando

2013-12-01

Gender identity disorder may be a stressful situation. Hormonal treatment seemed to improve the general health as it reduces psychological and social distress. The attachment style seemed to regulate distress in insecure individuals as they are more exposed to hypothalamic-pituitary-adrenal system dysregulation and subjective stress. The objectives of the study were to evaluate the presence of psychobiological distress and insecure attachment in transsexuals and to study their stress levels with reference to the hormonal treatment and the attachment pattern. We investigated 70 transsexual patients. We measured the cortisol levels and the perceived stress before starting the hormonal therapy and after about 12 months. We studied the representation of attachment in transsexuals by a backward investigation in the relations between them and their caregivers. We used blood samples for assessing cortisol awakening response (CAR); we used the Perceived Stress Scale for evaluating self-reported perceived stress and the Adult Attachment Interview to determine attachment styles. At enrollment, transsexuals reported elevated CAR; their values were out of normal. They expressed higher perceived stress and more attachment insecurity, with respect to normative sample data. When treated with hormone therapy, transsexuals reported significantly lower CAR (P < 0.001), falling within the normal range for cortisol levels. Treated transsexuals showed also lower perceived stress (P < 0.001), with levels similar to normative samples. The insecure attachment styles were associated with higher CAR and perceived stress in untreated transsexuals (P < 0.01). Treated transsexuals did not expressed significant differences in CAR and perceived stress by attachment. Our results suggested that untreated patients suffer from a higher degree of stress and that attachment insecurity negatively impacts the stress management. Initiating the hormonal treatment seemed to have a positive effect in reducing stress levels, whatever the attachment style may be. © 2013 International Society for Sexual Medicine.

Reduction in plasma vasopressin levels of dehydrated rats following acute stress

NASA Technical Reports Server (NTRS)

Keil, L. C.; Severs, W. B.

1977-01-01

Results are presented for an investigation directed to substantiate and extend preliminary findings of stress-induced reduction in plasma arginine vasopressin (pAVP). Since normally hydrated rats have very low levels of pAVP, it is difficult to measure reliably any decrease in pAVP that may result from stress. To overcome this problem, the pAVP levels of the tested rats were raised by dehydration prior to application of stress. A radioimmunoassay for pAVP is described and used to determine the levels of vasopressin in the plasma of nondehydrated and dehydrated rats after exposure to ether or acceleration stress. Plasma pAVP is also determined in rats following nicotine administration. It is shown that exposure of nondehydrated rats to ether or acceleration stress does not elicit any significant alterations in circulating pAVP levels while nicotine injections stimulate a marked increase. In particular, ether and acceleration stress produce a rapid reduction in the pAVP level of dehydrated rats, the decrease being observed in both large and small animals. The mechanism for this reduction in pAVP level following stress is yet unknown.

Negative Social Evaluation Impairs Executive Functions in Adolescents With Excess Weight: Associations With Autonomic Responses.

PubMed

Padilla, María Moreno; Fernández-Serrano, María J; Verdejo García, Antonio; Reyes Del Paso, Gustavo A

2018-06-22

Adolescents with excess weight suffer social stress more frequently than their peers with normal weight. To examine the impact of social stress, specifically negative social evaluation, on executive functions in adolescents with excess weight. We also examined associations between subjective stress, autonomic reactivity, and executive functioning. Sixty adolescents (aged 13-18 years) classified into excess weight or normal weight groups participated. We assessed executive functioning (working memory, inhibition, and shifting) and subjective stress levels before and after the Trier Social Stress Task (TSST). The TSST was divided into two phases according to the feedback of the audience: positive and negative social evaluation. Heart rate and skin conductance were recorded. Adolescents with excess weight showed poorer executive functioning after exposure to TSST compared with adolescents with normal weight. Subjective stress and autonomic reactivity were also greater in adolescents with excess weight than adolescents with normal weight. Negative social evaluation was associated with worse executive functioning and increased autonomic reactivity in adolescents with excess weight. The findings suggest that adolescents with excess weight are more sensitive to social stress triggered by negative evaluations. Social stress elicited deterioration of executive functioning in adolescents with excess weight. Evoked increases in subjective stress and autonomic responses predicted decreased executive function. Deficits in executive skills could reduce cognitive control abilities and lead to overeating in adolescents with excess weight. Strategies to cope with social stress to prevent executive deficits could be useful to prevent future obesity in this population.

Calnexin, an ER stress-induced protein, is a prognostic marker and potential therapeutic target in colorectal cancer.

PubMed

Ryan, Deborah; Carberry, Steven; Murphy, Áine C; Lindner, Andreas U; Fay, Joanna; Hector, Suzanne; McCawley, Niamh; Bacon, Orna; Concannon, Caoimhin G; Kay, Elaine W; McNamara, Deborah A; Prehn, Jochen H M

2016-07-01

Colorectal cancer (CRC) is a leading cause of cancer mortality in the Western world and commonly treated with genotoxic chemotherapy. Stress in the endoplasmic reticulum (ER) was implicated to contribute to chemotherapeutic resistance. Hence, ER stress related protein may be of prognostic or therapeutic significance. The expression levels of ER stress proteins calnexin, calreticulin, GRP78 and GRP94 were determined in n = 23 Stage II and III colon cancer fresh frozen tumour and matched normal tissue samples. Data were validated in a cohort of n = 11 rectal cancer patients treated with radiochemotherapy in the neoadjuvant setting. The calnexin gene was silenced using siRNA in HCT116 cells. There were no increased levels of ER stress proteins in tumour compared to matched normal tissue samples in Stage II or III CRC. However, increased calnexin protein levels were predictive of poor clinical outcome in the patient cohort. Data were validated in the rectal cancer cohort treated in the neoadjuvant setting. Calnexin gene-silencing significantly reduced cell survival and increased cancer cell susceptibility to 5FU chemotherapy. Increased tumour protein levels of calnexin may be of prognostic significance in CRC, and calnexin may represent a potential target for future therapies.

Stress perturbation associated with the Amazonas and other ancient continental rifts

USGS Publications Warehouse

Zoback, M.L.; Richardson, R.M.

1996-01-01

The state of stress in the vicinity of old continental rifts is examined to investigate the possibility that crustal structure associated with ancient rifts (specifically a dense rift pillow in the lower crust) may modify substantially the regional stress field. Both shallow (2.0-2.6 km depth) breakout data and deep (20-45 km depth) crustal earthquake focal mechanisms indicate a N to NNE maximum horizontal compression in the vicinity of the Paleozoic Amazonas rift in central Brazil. This compressive stress direction is nearly perpendicular to the rift structure and represents a ???75?? rotation relative to a regional E-W compressive stress direction in the South American plate. Elastic two-dimensional finite element models of the density structure associated with the Amazonas rift (as inferred from independent gravity modeling) indicate that elastic support of this dense feature would generate horizontal rift-normal compressional stresses between 60 and 120 MPa, with values of 80-100 MPa probably most representative of the overall structure. The observed ???75?? stress rotation constrains the ratio of the regional horizontal stress difference to the rift-normal compressive stress to be between 0.25 and 1.0, suggesting that this rift-normal stress may be from 1 to 4 times larger than the regional horizontal stress difference. A general expression for the modification of the normalized local horizontal shear stress (relative to the regional horizontal shear stress) shows that the same ratio of the rift-normal compression relative to the regional horizontal stress difference, which controls the amount of stress rotation, also determines whether the superposed stress increases or decreases the local maximum horizontal shear stress. The potential for fault reactivation of ancient continental rifts in general is analyzed considering both the local stress rotation and modification of horizontal shear stress for both thrust and strike-slip stress regimes. In the Amazonas rift case, because the observed stress rotation only weakly constrains the ratio of the regional horizontal stress difference to the rift-normal compression to be between 0.25 and 1.0, our analysis is inconclusive because the resultant normalized horizontal shear stress may be reduced (for ratios >0.5) or enhanced (for ratios <0.5). Additional information is needed on all three stress magnitudes to predict how a change in horizontal shear stress directly influences the likelihood of faulting in the thrust-faulting stress regime in the vicinity of the Amazonas rift. A rift-normal stress associated with the seismically active New Madrid ancient rift may be sufficient to rotate the horizontal stress field consistent with strike-slip faults parallel to the axis of the rift, although this results in a 20-40% reduction in the local horizontal shear stress within the seismic zone. Sparse stress data in the vicinity of the seismically quiescent Midcontinent rift of the central United States suggest a stress state similar to that of New Madrid, with the local horizontal shear stress potentially reduced by as much as 60%. Thus the markedly different levels of seismic activity associated with these two subparallel ancient rifts is probably due to other factors than stress perturbations due to dense rift pillows. The modeling and analysis here demonstrate that rift-normal compressive stresses are a significant source of stress acting on the lithosphere and that in some cases may be a contributing factor to the association of intraplate seismicity with old zones of continental extension.

Analysis of space-time projection of differential and Michelson-type speckle-interferometer output signal for cardiovibration measurement

NASA Astrophysics Data System (ADS)

Ulyanov, Sergey S.; Tuchin, Valery V.

1993-06-01

The sex differences in cardiovascular system responses to a mild noise stress are established using the physiological and the dynamic systems theory methods. Lower levels of basal systolic arterial pressure and higher rates of its dropping and normalization under influence and after its cessation are typical for women. There are no hypertensive responses to stresses in women in contrast to men. The normalized entropy of the ECG signal, describing the physiological variability, increases in women and decreases in men. The advantages of female cardiovascular system response to mild stresses are discussed.

The effect of glucose concentration and sodium phenylbutyrate treatment on mitochondrial bioenergetics and ER stress in 3T3-L1 adipocytes.

PubMed

Tanis, Ross M; Piroli, Gerardo G; Day, Stani D; Frizzell, Norma

2015-01-01

While the 3T3-L1 adipocyte model is routinely used for the study of obesity and diabetes, the mitochondrial respiratory profile in normal versus high glucose has not been examined in detail. We matured adipocytes in normal (5mM) or high (30 mM) glucose and insulin and examined the mitochondrial bioenergetics. We also assessed the requirement for the Unfolded Protein Response (UPR) and ER stress under these conditions. Basal respiration was ~1.7-fold greater in adipocytes that had matured in 30 mM glucose; however, their ability to increase oxygen consumption in response to stress was impaired. Adipogenesis proceeded in both normal and high glucose with concomitant activation of the UPR, but only high glucose was associated with increased levels of ER stress and mitochondrial stress as observed by parallel increases in CHOP and protein succination. Treatment of adipocytes with sodium phenylbutyrate relieved mitochondrial stress through a reduction in mitochondrial respiration. Our data suggests that mitochondrial stress, protein succination and ER stress are uniquely linked in adipocytes matured in high glucose. Copyright © 2014 Elsevier B.V. All rights reserved.

The Effect of Glucose Concentration and Sodium Phenylbutyrate Treatment on Mitochondrial Bioenergetics and ER Stress in 3T3-L1 Adipocytes

PubMed Central

Tanis, Ross M.; Piroli, Gerardo G.; Day, Stani D.; Frizzell, Norma

2016-01-01

While the 3T3-L1 adipocyte model is routinely used for the study of obesity and diabetes, the mitochondrial respiratory profile in normal versus high glucose has not been examined in detail. We matured adipocytes in normal (5 mM) or high (30 mM) glucose and insulin and examined the mitochondrial bioenergetics. We also assessed the requirement for the Unfolded Protein Response (UPR) and ER stress under these conditions. Basal respiration was ∼1.7-fold greater in adipocytes that had matured in 30 mM glucose; however, their ability to increase oxygen consumption in response to stress was impaired. Adipogenesis proceeded in both normal and high glucose with concomitant activation of the UPR, but only high glucose was associated with increased levels of ER stress and mitochondrial stress as observed by parallel increases in CHOP and protein succination. Treatment of adipocytes with sodium phenylbutyrate relieved mitochondrial stress through a reduction in mitochondrial respiration. Our data suggests that mitochondrial stress, protein succination and ER stress are uniquely linked in adipocytes matured in high glucose. PMID:25448036

Cortisol as a Biomarker of Stress in Term Human Labor: Physiological and Methodological Issues

PubMed Central

Newton, Edward R.; Tanner, Charles J.; Heitkemper, Margaret M.

2013-01-01

Literature on the use of plasma cortisol to quantify psychophysiological stress in humans is extensive. However, in parturition at term gestation the use of cortisol as a biomarker of stress is particularly complex. Plasma cortisol levels increase as labor progresses. This increase seems to be important for maintenance of maternal/fetal wellbeing and facilitation of normal labor progress. Unique physiological and methodological issues involved in the use of cortisol as a biomarker of stress in labor present challenges for researchers. This review examines these issues, suggests mixed methods and within-subject repeated measures designs, and offers recommendations for assay procedures for parturient sampling. Documentation of clinical interventions and delivery outcomes may elucidate relationships among psychophysiological stressors, cortisol and normal labor progress. With attention to these methodological issues, analysis of plasma cortisol may lead to clinical interventions that support normal labor physiology. PMID:23338011

Differential effects of cyclic and constant stress on ATP release and mucociliary transport by human airway epithelia

PubMed Central

Button, Brian; Picher, Maryse; Boucher, Richard C

2007-01-01

In the lungs, the first line of defence against bacterial infection is the thin layer of airway surface liquid (ASL) lining the airway surface. The superficial airway epithelium exhibits complex regulatory pathways that blend ion transport to adjust ASL volume to maintain proper mucociliary clearance (MCC). We hypothesized that stresses generated by airflow and transmural pressures during breathing govern ASL volume by regulating the rate of epithelial ATP release. Luminal ATP, via interactions with apical membrane P2-purinoceptors, regulates the balance of active ion secretion versus absorption to maintain ASL volume at optimal levels for MCC. In this study we tested the hypothesis that cyclic compressive stress (CCS), mimicking normal tidal breathing, regulates ASL volume in airway epithelia. Polarized tracheobronchial epithelial cultures from normal and cystic fibrosis (CF) subjects responded to a range of CCS by increasing the rate of ATP release. In normal airway epithelia, the CCS-induced increase in ASL ATP concentration was sufficient to induce purinoceptor-mediated increases in ASL height and MCC, via inhibition of epithelial Na+-channel-mediated Na+ absorption and stimulation of Cl− secretion through CFTR and the Ca2+-activated chloride channels. In contrast, static, non-oscillatory stress did not stimulate ATP release, ion transport or MCC, emphasizing the importance of rhythmic mechanical stress for airway defence. In CF airway cultures, which exhibit basal ASL depletion, CCS was partially effective, producing less ASL volume secretion than in normal cultures, but a level sufficient to restore MCC. The present data suggest that CCS may (1) regulate ASL volume in the normal lung and (2) improve clearance in the lungs of CF patients, potentially explaining the beneficial role of exercise in lung defence. PMID:17317749

On the Normal Force Mechanotransduction of Human Umbilical Vein Endothelial Cells

NASA Astrophysics Data System (ADS)

Vahabikashi, Amir; Wang, Qiuyun; Wilson, James; Wu, Qianhong; Vucbmss Team

2016-11-01

In this paper, we report a cellular biomechanics study to examine the normal force mechanotransduction of Human Umbilical Vein Endothelial Cells (HUVECs) with their implications on hypertension. Endothelial cells sense mechanical forces and adjust their structure and function accordingly. The mechanotransduction of normal forces plays a vital role in hypertension due to the higher pressure buildup inside blood vessels. Herein, HUVECs were cultured to full confluency and then exposed to different mechanical loadings using a novel microfluidic flow chamber. One various pressure levels while keeps the shear stress constant inside the flow chamber. Three groups of cells were examined, the control group (neither shear nor normal stresses), the normal pressure group (10 dyne/cm2 of shear stress and 95 mmHg of pressure), and the hypertensive group (10 dyne/cm2 of shear stress and 142 mmHg of pressure). Cellular response characterized by RT-PCR method indicates that, COX-2 expressed under normal pressure but not high pressure; Mn-SOD expressed under both normal and high pressure while this response was stronger for normal pressure; FOS and e-NOS did not respond under any condition. The differential behavior of COX-2 and Mn-SOD in response to changes in pressure, is instrumental for better understanding the pathogenesis of hypertensive cardiovascular diseases. This research was supported by the National Science Foundation under Award #1511096.

Housing in Pyramid Counteracts Neuroendocrine and Oxidative Stress Caused by Chronic Restraint in Rats

PubMed Central

Rao, Guruprasad; Murthy, K. Dilip; Bhat, P. Gopalakrishna

2007-01-01

The space within the great pyramid and its smaller replicas is believed to have an antistress effect. Research has shown that the energy field within the pyramid can protect the hippocampal neurons of mice from stress-induced atrophy and also reduce neuroendocrine stress, oxidative stress and increase antioxidant defence in rats. In this study, we have, for the first time, attempted to study the antistress effects of pyramid exposure on the status of cortisol level, oxidative damage and antioxidant status in rats during chronic restraint stress. Adult female Wistar rats were divided into four groups as follows: normal controls (NC) housed in home cage and left in the laboratory; restrained rats (with three subgroups) subject to chronic restraint stress by placing in a wire mesh restrainer for 6 h per day for 14 days, the restrained controls (RC) having their restrainers kept in the laboratory; restrained pyramid rats (RP) being kept in the pyramid; and restrained square box rats (RS) in the square box during the period of restraint stress everyday. Erythrocyte malondialdehyde (MDA) and plasma cortisol levels were significantly increased and erythrocyte-reduced glutathione (GSH) levels, erythrocyte glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were significantly decreased in RC and RS rats as compared to NC. However, these parameters were maintained to near normal levels in RP rats which showed significantly decreased erythrocyte MDA and plasma cortisol and significantly increased erythrocyte GSH levels, erythrocyte GSH-Px and SOD activities when compared with RS rats. The results showed that housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats. PMID:17342239

Surplus dietary tryptophan reduces plasma cortisol and noradrenaline concentrations and enhances recovery after social stress in pigs.

PubMed

Koopmans, Sietse Jan; Ruis, Marko; Dekker, Ruud; van Diepen, Hans; Korte, Mechiel; Mroz, Zdzislaw

2005-07-21

Social stress occurs in intensive pig farming due to aggressive behavior. This stress may be reduced at elevated dietary levels of tryptophan (TRP). In this study, we compared the effects of high (13.2%) vs. normal (3.4%) dietary TRP to large neutral amino acid (LNAA) ratios on behavior and stress hormones in catheterized pigs ( approximately 50 kg BW), which were exposed to social stress by placing them twice into the territory of a dominant pig ( approximately 60 kg) for 15 min. Pre-stress plasma TRP concentrations were 156+/-15 vs. 53+/-6 micromol/l (p<0.01) in pigs on the high vs. normal TRP diets, respectively. Pre-stress plasma cortisol and noradrenaline concentrations were twofold (p<0.01) and 1.4-fold (p<0.05) lower but plasma adrenaline concentration was similar in pigs on the high vs. normal TRP diets, respectively. During the social confrontations, pigs on the high vs. normal TRP diets show a tendency towards reduced active avoidance behavior (3.2+/-1.1 vs. 6.7+/-1.2 min, p<0.1) but their physical activity (8.5+/-0.6 vs. 10.2+/-0.8 min) and aggressive attitude towards the dominant pig (11+/-3 vs. 7+/-2 times biting) were similar. Immediate (+5 min) post-stress plasma cortisol, noradrenaline and adrenaline responses were similar among dietary groups. After the social confrontations, the post-stress plasma cortisol, noradrenaline and adrenaline concentrations and/or curves (from +5 min to 2 h) were lower/steeper (p<0.05) in pigs on the high vs. normal TRP diets. In summary, surplus TRP in diets for pigs (1) does not significantly affect behavior when exposed to social stress, (2) reduces basal plasma cortisol and noradrenaline concentrations, (3) does not affect the immediate hormonal response to stress, and (4) reduces the long-term hormonal response to stress. In general, pigs receiving high dietary TRP were found to be less affected by stress.

PtrA/NINV, an alkaline/neutral invertase gene of Poncirus trifoliata, confers enhanced tolerance to multiple abiotic stresses by modulating ROS levels and maintaining photosynthetic efficiency.

PubMed

Dahro, Bachar; Wang, Fei; Peng, Ting; Liu, Ji-Hong

2016-03-29

Alkaline/neutral invertase (A/N-INV), an enzyme that hydrolyzes sucrose irreversibly into glucose and fructose, is essential for normal plant growth,development, and stress tolerance. However, the physiological and/or molecular mechanism underpinning the role of A/N-INV in abiotic stress tolerance is poorly understood. In this report, an A/N-INV gene (PtrA/NINV) was isolated from Poncirus trifoliata, a cold-hardy relative of citrus, and functionally characterized. PtrA/NINV expression levels were induced by cold, salt, dehydration, sucrose, and ABA, but decreased by glucose. PtrA/NINV was found to localize in both chloroplasts and mitochondria. Overexpression of PtrA/NINV conferred enhanced tolerance to multiple stresses, including cold, high salinity, and drought, as supported by lower levels of reactive oxygen species (ROS), reduced oxidative damages, decreased water loss rate, and increased photosynthesis efficiency, relative to wild-type (WT). The transgenic plants exhibited higher A/N-INV activity and greater reducing sugar content under normal and stress conditions. PtrA/NINV is an important gene implicated in sucrose decomposition, and plays a positive role in abiotic stress tolerance by promoting osmotic adjustment, ROS detoxification and photosynthesis efficiency. Thus, PtrA/NINV has great potential to be used in transgenic breeding for improvement of stress tolerance.

Cumulative hip contact stress predicts osteoarthritis in DDH.

PubMed

Mavcic, Blaz; Iglic, Ales; Kralj-Iglic, Veronika; Brand, Richard A; Vengust, Rok

2008-04-01

Hip stresses are generally believed to influence whether a hip develops osteoarthritis (OA); similarly, various osteotomies have been proposed to reduce contact stresses and the risk of OA. We asked whether elevated hip contact stress predicted osteoarthritis in initially asymptomatic human hips. We identified 58 nonoperatively treated nonsubluxated hips with developmental dysplasia (DDH) without symptoms at skeletal maturity; the control group included 48 adult hips without hip disease. The minimum followup was 20 years (mean, 29 years; range, 20-41 years). Peak contact stress was computed with the HIPSTRESS method using anteroposterior pelvic radiographs at skeletal maturity. The cumulative contact stress was determined by multiplying the peak contact stress by age at followup. We compared WOMAC scores and radiographic indices of OA. Dysplastic hips had higher mean peak contact and higher mean cumulative contact stress than normal hips. Mean WOMAC scores and percentage of asymptomatic hips in the study group (mean age 51 years) were similar to those in the control group (mean age 68 years). After adjusting for gender and age, the cumulative contact stress, Wiberg center-edge angle, body mass index, but not the peak contact stress, independently predicted the final WOMAC score in dysplastic hips but not in normal hips. Cumulative contact stress predicted early hip OA better than the Wiberg center-edge angle. Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Antioxidant potential of the methanol-methylene chloride extract of Terminalia glaucescens leaves on mice liver in streptozotocin-induced stress.

PubMed

Njomen, Guy Bertrand Sabas Nya; Kamgang, René; Oyono, Jean Louis Essame; Njikam, Njifutie

2008-11-01

The antioxidant effect of the methanol-methylene chloride extract of Terminalia glaucescens (Combretaceae) leaves was investigated in streptozotocin (STZ)-induced oxidative stress. Oxidative stress was induced in mice by a daily dose of STZ (45 mg/kg body weight i.p.) for five days. From day one, before STZ injection, normal and diabetic-test mice received an oral dose of the extract (100 or 300 mg/kg b.w.) daily. Plasma metabolites, lipid peroxidation, and antioxidant enzymes in the liver were assessed and gain in body weight recorded. In normal mice the plant extract reduced food and water intake, blood glucose and LDL-C level and body weight gain, did not affect the lipid peroxidation in the liver, while the antioxidant enzyme activities seemed increased. Blood glucose was decreased (P < 0.05) in normal mice treated with 300 mg/kg extract. Diabetic mice pretreated with 100 mg/kg extract as diabetic control mice (DC) showed significant (P < 0.001) body weight loss, polyphagia and polydipsia, high plasma glucose level, decrease in the liver catalase, peroxidase, and superoxide dismutase activities, and increase in lipid peroxidation. The HDL-C level was lowered (P < 0.05) whereas LDL-C increased. In 300 mg/kg extract-pretreated diabetic mice the extract prevented body weight loss, increase of blood glucose level, lipid peroxidation in liver, food and water intake, and lowering of plasma HDL-C level and liver antioxidants; this extract prevented LDL-C level increase. These results indicate that T. glaucescens protects against STZ-induced oxidative stress and could thus explain its traditional use for diabetes and obesity treatment or management.

Effects of Parsley (Petroselinum crispum) and its Flavonol Constituents, Kaempferol and Quercetin, on Serum Uric Acid Levels, Biomarkers of Oxidative Stress and Liver Xanthine Oxidoreductase Aactivity inOxonate-Induced Hyperuricemic Rats.

PubMed

Haidari, Fatemeh; Keshavarz, Seid Ali; Mohammad Shahi, Majid; Mahboob, Soltan-Ali; Rashidi, Mohammad-Reza

2011-01-01

Increased serum uric acid is known to be a major risk related to the development of several oxidative stress diseases. The aim of this study was to investigate the effect of parsley, quercetin and kaempferol on serum uric acid levels, liver xanthine oxidoreductase activity and two non-invasive biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) in normal and oxonate-induced hyperuricemic rats. A total of 60 male Wistar rats were randomly divided into ten equal groups; including 5 normal groups (vehicle, parsley, quercetin, kaempferol and allopurinol) and 5 hyperuricemic groups (vehicle, parsley, quercetin, kaempferol and allopurinol). Parsley (5 g/Kg), quercetin (5 mg/Kg), kaempferol (5 mg/Kg) and allopurinol (5 mg/Kg) were administrated to the corresponding groups by oral gavage once a day for 2 weeks. The results showed that parsley and its flavonol did not cause any significant reduction in the serum uric acid levels in normal rats, but significantly reduced the serum uric acid levels of hyperuricemic rats in a time-dependent manner. All treatments significantly inhibited liver xanthine oxidoreductase activity. Parsley, kaempferol and quercetin treatment led also to a significant increase in total antioxidant capacity and decrease in malondialdehyde concentration in hyperuricemic rats. Although the hypouricemic effect of allopurinol was much higher than that of parsley and its flavonol constituents, it could not significantly change oxidative stress biomarkers. These features of parsley and its flavonols make them as a possible alternative for allopurinol, or at least in combination therapy to minimize the side effects of allopurinol to treat hyperuricemia and oxidative stress diseases.

Effects of Parsley (Petroselinum crispum) and its Flavonol Constituents, Kaempferol and Quercetin, on Serum Uric Acid Levels, Biomarkers of Oxidative Stress and Liver Xanthine Oxidoreductase Aactivity inOxonate-Induced Hyperuricemic Rats

PubMed Central

Haidari, Fatemeh; Keshavarz, Seid Ali; Mohammad Shahi, Majid; Mahboob, Soltan-Ali; Rashidi, Mohammad-Reza

2011-01-01

Increased serum uric acid is known to be a major risk related to the development of several oxidative stress diseases. The aim of this study was to investigate the effect of parsley, quercetin and kaempferol on serum uric acid levels, liver xanthine oxidoreductase activity and two non-invasive biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) in normal and oxonate-induced hyperuricemic rats. A total of 60 male Wistar rats were randomly divided into ten equal groups; including 5 normal groups (vehicle, parsley, quercetin, kaempferol and allopurinol) and 5 hyperuricemic groups (vehicle, parsley, quercetin, kaempferol and allopurinol). Parsley (5 g/Kg), quercetin (5 mg/Kg), kaempferol (5 mg/Kg) and allopurinol (5 mg/Kg) were administrated to the corresponding groups by oral gavage once a day for 2 weeks. The results showed that parsley and its flavonol did not cause any significant reduction in the serum uric acid levels in normal rats, but significantly reduced the serum uric acid levels of hyperuricemic rats in a time-dependent manner. All treatments significantly inhibited liver xanthine oxidoreductase activity. Parsley, kaempferol and quercetin treatment led also to a significant increase in total antioxidant capacity and decrease in malondialdehyde concentration in hyperuricemic rats. Although the hypouricemic effect of allopurinol was much higher than that of parsley and its flavonol constituents, it could not significantly change oxidative stress biomarkers. These features of parsley and its flavonols make them as a possible alternative for allopurinol, or at least in combination therapy to minimize the side effects of allopurinol to treat hyperuricemia and oxidative stress diseases. PMID:24250417

Perceived early-life maternal care and the cortisol response to repeated psychosocial stress.

PubMed

Engert, Veronika; Efanov, Simona I; Dedovic, Katarina; Duchesne, Annie; Dagher, Alain; Pruessner, Jens C

2010-11-01

In the past decade, a body of animal and human research has revealed a profound influence of early-life experiences, ranging from variations in parenting behaviour to severe adversity, on hypothalamic-pituitary-adrenal axis regulation in adulthood. In our own previous studies, we have shown how variations in early-life parental care influence the development of the hippocampus and modify the cortisol awakening response. In the present study, we investigated the influence of early-life maternal care on cortisol, heart rate and subjective psychological responses to the repeated administration of a psychosocial laboratory stressor in a population of 63 healthy young adults. Low, medium and high early-life maternal care groups were identified using the Parental Bonding Instrument. Controlling for the effect of sex, we found an inverted u-shaped relation between increasing levels of maternal care and cortisol stress responsivity. Specifically, overall and stress-induced cortisol levels went from below normal in the low maternal care, to normal in the medium care, back to below normal in the high maternal care groups. We found no group differences with respect to heart rate and subjective psychological stress measures. Whereas low and high maternal care groups exhibited similarly low endocrine stress responses, their psychological profiles were opposed with increased levels of depression and anxiety and decreased self-esteem in the low care group. Sex was unequally distributed among maternal care groups, whereby the number of men with low maternal care was too small to allow introducing sex as a second between-group variable. We discuss the potential significance of this dissociation between endocrine and psychological parameters with respect to stress vulnerability and resistance for each maternal care group.

Perceived early-life maternal care and the cortisol response to repeated psychosocial stress

PubMed Central

Engert, Veronika; Efanov, Simona I.; Dedovic, Katarina; Duchesne, Annie; Dagher, Alain; Pruessner, Jens C.

2010-01-01

Background In the past decade, a body of animal and human research has revealed a profound influence of early-life experiences, ranging from variations in parenting behaviour to severe adversity, on hypothalamic–pituitary–adrenal axis regulation in adulthood. In our own previous studies, we have shown how variations in early-life parental care influence the development of the hippocampus and modify the cortisol awakening response. Methods In the present study, we investigated the influence of early-life maternal care on cortisol, heart rate and subjective psychological responses to the repeated administration of a psychosocial laboratory stressor in a population of 63 healthy young adults. Low, medium and high early-life maternal care groups were identified using the Parental Bonding Instrument. Results Controlling for the effect of sex, we found an inverted u-shaped relation between increasing levels of maternal care and cortisol stress responsivity. Specifically, overall and stress-induced cortisol levels went from below normal in the low maternal care, to normal in the medium care, back to below normal in the high maternal care groups. We found no group differences with respect to heart rate and subjective psychological stress measures. Whereas low and high maternal care groups exhibited similarly low endocrine stress responses, their psychological profiles were opposed with increased levels of depression and anxiety and decreased self-esteem in the low care group. Limitations Sex was unequally distributed among maternal care groups, whereby the number of men with low maternal care was too small to allow introducing sex as a second between-group variable. Conclusion We discuss the potential significance of this dissociation between endocrine and psychological parameters with respect to stress vulnerability and resistance for each maternal care group. PMID:20964960

Activation of ATP-sensitive potassium channel by iptakalim normalizes stress-induced HPA axis disorder and depressive behaviour by alleviating inflammation and oxidative stress in mouse hypothalamus.

PubMed

Zhao, Xiao-Jie; Zhao, Zhan; Yang, Dan-Dan; Cao, Lu-Lu; Zhang, Ling; Ji, Juan; Gu, Jun; Huang, Ji-Ye; Sun, Xiu-Lan

2017-04-01

Stress-induced disturbance of the hypothalamic-pituitary-adrenal (HPA) axis is strongly implicated in incidence of mood disorders. A heightened neuroinflammatory response and oxidative stress play a fundamental role in the dysfunction of the HPA axis. We have previously demonstrated that iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could prevent oxidative injury and neuroinflammation against multiple stimuli-induced brain injury. The present study was to demonstrate the impacts of Ipt in stress-induced HPA axis disorder and depressive behavior. We employed 2 stress paradigms: 8 weeks of continuous restraint stress (chronic restraint stress, CRS) and 2h of restraint stress (acute restraint stress, ARS), to mimic both chronic stress and severe acute stress. Prolonged (4 weeks) and short-term (a single injection) Ipt treatment was administered 30min before each stress paradigm. We found that HPA axis was altered after stress, with different responses to CRS (lower ACTH and CORT, higher AVP, but normal CRH) and ARS (higher CRH, ACTH and CORT, but normal AVP). Both prolonged and short-term Ipt treatment normalized stress-induced HPA axis disorders and abnormal behaviors in mice. CRS and ARS up-regulated mRNA levels of inflammation-related molecules (TNFα, IL-1β, IL-6 and TLR4) and oxidative stress molecules (gp91phox, iNOS and Nrf2) in the mouse hypothalamus. Double immunofluorescence showed CRS and ARS increased microglia activation (CD11b and TNFα) and oxidative stress in neurons (NeuN and gp91phox), which were alleviated by Ipt. Therefore, the present study reveals that Ipt could prevent against stress-induced HPA axis disorders and depressive behavior by alleviating inflammation and oxidative stress in the hypothalamus. Copyright © 2017 Elsevier Inc. All rights reserved.

Impedance-Based Pre-Stress Monitoring of Rock Bolts Using a Piezoceramic-Based Smart Washer-A Feasibility Study.

PubMed

Wang, Bo; Huo, Linsheng; Chen, Dongdong; Li, Weijie; Song, Gangbing

2017-01-27

Pre-stress degradation or looseness of rock bolts in mining or tunnel engineering threatens the stability and reliability of the structures. In this paper, an innovative piezoelectric device named a "smart washer" with the impedance method is proposed with the aim of developing a real-time device to monitor the pre-stress level of rock bolts. The proposed method was verified through tests on a rock bolt specimen. By applying high-frequency sweep excitations (typically >30 kHz) to the smart washer that was installed on the rock bolt specimen, we observed that the variation in impedance signatures indicated the rock bolt pre-stress status. With the degradation of rock bolt pre-stress, the frequency in the dominating peak of the real part of the electrical impedance signature increased. To quantify the effectiveness of the proposed technique, a normalized root mean square deviation (RMSD) index was developed to evaluate the degradation level of the rock bolt pre-stress. The experimental results demonstrated that the normalized RMSD-based looseness index, which was computed from the impedance value detected by the "smart washer", increased with loss of the pre-stress of the rock bolt. Therefore, the proposed method can effectively detect the degradation of rock bolt pre-stress, as demonstrated by experiments.

Impedance-Based Pre-Stress Monitoring of Rock Bolts Using a Piezoceramic-Based Smart Washer—A Feasibility Study

PubMed Central

Wang, Bo; Huo, Linsheng; Chen, Dongdong; Li, Weijie; Song, Gangbing

2017-01-01

Pre-stress degradation or looseness of rock bolts in mining or tunnel engineering threatens the stability and reliability of the structures. In this paper, an innovative piezoelectric device named a “smart washer” with the impedance method is proposed with the aim of developing a real-time device to monitor the pre-stress level of rock bolts. The proposed method was verified through tests on a rock bolt specimen. By applying high-frequency sweep excitations (typically >30 kHz) to the smart washer that was installed on the rock bolt specimen, we observed that the variation in impedance signatures indicated the rock bolt pre-stress status. With the degradation of rock bolt pre-stress, the frequency in the dominating peak of the real part of the electrical impedance signature increased. To quantify the effectiveness of the proposed technique, a normalized root mean square deviation (RMSD) index was developed to evaluate the degradation level of the rock bolt pre-stress. The experimental results demonstrated that the normalized RMSD-based looseness index, which was computed from the impedance value detected by the “smart washer”, increased with loss of the pre-stress of the rock bolt. Therefore, the proposed method can effectively detect the degradation of rock bolt pre-stress, as demonstrated by experiments. PMID:28134811

Heart rate variability (HRV): an indicator of stress

NASA Astrophysics Data System (ADS)

Kaur, Balvinder; Durek, Joseph J.; O'Kane, Barbara L.; Tran, Nhien; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

2014-05-01

Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy [3], [4], [10] & [11]. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one [4], [13] & [14]. In all of these past works, although processing is done in both frequency and time domains, few classification algorithms have been explored for classifying normal from stressed RRintervals. In this paper we used 30 s intervals from the Electrocardiogram (ECG) time series collected during normal and stressed conditions, produced by means of a modified version of the Trier social stress test, to compute HRV-driven features and subsequently applied a set of classification algorithms to distinguish stressed from normal conditions. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications, namely 1) logistic regression (LR) [16] and 2) linear discriminant analysis (LDA) [6]. Classification performance for various levels of stress over the entire test was quantified using precision, accuracy, sensitivity and specificity measures. Results from both classifiers were then compared to find an optimal classifier and HRV features for stress detection. This work, performed under an IRB-approved protocol, not only provides a method for developing models and classifiers based on human data, but also provides a foundation for a stress indicator tool based on HRV. Further, these classification tools will not only benefit many civilian applications for detecting stress, but also security and military applications for screening such as: border patrol, stress detection for deception [3],[17], and wounded-warrior triage [12].

Stress induction in the bacteria Shewanella oneidensis and Deinococcus radiodurans in response to below-background ionizing radiation.

PubMed

Castillo, Hugo; Schoderbek, Donald; Dulal, Santosh; Escobar, Gabriela; Wood, Jeffrey; Nelson, Roger; Smith, Geoffrey

2015-01-01

The 'Linear no-threshold' (LNT) model predicts that any amount of radiation increases the risk of organisms to accumulate negative effects. Several studies at below background radiation levels (4.5-11.4 nGy h(-1)) show decreased growth rates and an increased susceptibility to oxidative stress. The purpose of our study is to obtain molecular evidence of a stress response in Shewanella oneidensis and Deinococcus radiodurans grown at a gamma dose rate of 0.16 nGy h(-1), about 400 times less than normal background radiation. Bacteria cultures were grown at a dose rate of 0.16 or 71.3 nGy h(-1) gamma irradiation. Total RNA was extracted from samples at early-exponential and stationary phases for the rt-PCR relative quantification (radiation-deprived treatment/background radiation control) of the stress-related genes katB (catalase), recA (recombinase), oxyR (oxidative stress transcriptional regulator), lexA (SOS regulon transcriptional repressor), dnaK (heat shock protein 70) and SOA0154 (putative heavy metal efflux pump). Deprivation of normal levels of radiation caused a reduction in growth of both bacterial species, accompanied by the upregulation of katB, recA, SOA0154 genes in S. oneidensis and the upregulation of dnaK in D. radiodurans. When cells were returned to background radiation levels, growth rates recovered and the stress response dissipated. Our results indicate that below-background levels of radiation inhibited growth and elicited a stress response in two species of bacteria, contrary to the LNT model prediction.

78 FR 41716 - Hours of Service; Limited 90-Day Waiver From the 30-Minute Rest Break Requirement for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-11

..., is a significant concern to the agricultural industry. The animals face a variety of stresses... the transportation of pigs because these animals do not sweat and are subject to heat stress. When heat stress occurs, a pig's body temperature rises to a level that it cannot control through its normal...

Interactions between Polygonal Normal Faults and Larger Normal Faults, Offshore Nova Scotia, Canada

NASA Astrophysics Data System (ADS)

Pham, T. Q. H.; Withjack, M. O.; Hanafi, B. R.

2017-12-01

Polygonal faults, small normal faults with polygonal arrangements that form in fine-grained sedimentary rocks, can influence ground-water flow and hydrocarbon migration. Using well and 3D seismic-reflection data, we have examined the interactions between polygonal faults and larger normal faults on the passive margin of offshore Nova Scotia, Canada. The larger normal faults strike approximately E-W to NE-SW. Growth strata indicate that the larger normal faults were active in the Late Cretaceous (i.e., during the deposition of the Wyandot Formation) and during the Cenozoic. The polygonal faults were also active during the Cenozoic because they affect the top of the Wyandot Formation, a fine-grained carbonate sedimentary rock, and the overlying Cenozoic strata. Thus, the larger normal faults and the polygonal faults were both active during the Cenozoic. The polygonal faults far from the larger normal faults have a wide range of orientations. Near the larger normal faults, however, most polygonal faults have preferred orientations, either striking parallel or perpendicular to the larger normal faults. Some polygonal faults nucleated at the tip of a larger normal fault, propagated outward, and linked with a second larger normal fault. The strike of these polygonal faults changed as they propagated outward, ranging from parallel to the strike of the original larger normal fault to orthogonal to the strike of the second larger normal fault. These polygonal faults hard-linked the larger normal faults at and above the level of the Wyandot Formation but not below it. We argue that the larger normal faults created stress-enhancement and stress-reorientation zones for the polygonal faults. Numerous small, polygonal faults formed in the stress-enhancement zones near the tips of larger normal faults. Stress-reorientation zones surrounded the larger normal faults far from their tips. Fewer polygonal faults are present in these zones, and, more importantly, most polygonal faults in these zones were either parallel or perpendicular to the larger faults.

Laying hen responses to acute heat stress and carbon dioxide supplementation: I. Blood gas changes and plasma lactate accumulation.

PubMed

Koelkebeck, K W; Odom, T W

1994-04-01

Exposure to heat stress lowered partial pressure of arterial blood carbon dioxide (paCO2), arterial blood bicarbonate ion (HCO3-), but increased arterial blood pH (pHa) and plasma lactate (LA). Increasing ambient carbon dioxide (CO2) to 1.5% increased paCO2 from hypocapnic levels to normocapnic levels, raised HCO3-, lowered pHa and plasma LA to pre-heat stress levels. Following CO2 treatment, respiratory alkalosis conditions returned. It was evident in this study that increasing ambient chamber CO2 to 1.5% was effective in ameliorating acid-base disturbances and reducing elevated levels of plasma LA which normally develops when laying hens are subjected to an acute heat stress exposure.

Is stress level related to Dengue Hemorrhagic fever cases in Semarang?

NASA Astrophysics Data System (ADS)

Purdianingrum, Julliana; Adib Mubarok, Muhammad; Putri Sunarno, Rahmah; Khairunisa, Ummi; Endah Wahyuningsih, Nur; Murwani, Retno; Budiharjo, Anto

2018-05-01

Dengue Hemorrhagic Fever (DHF) is transmitted to humans by dengue virus harboring Aedes aegypti. Immune response against viral infection can be influenced by stress as stress could weaken immune response. Stress can cause illness through physiological changes and changes in immune function. The immunological changes associated with stress were adapted from the immunological changes in response to infection. The purpose of this study was to determine the relationship between DHF cases with stress level._We used a case control study with DHF sample cases from three hospitals in Semarang city (n=27) from the period of March to May 2017 and the control groups from healthy respondents with matched age, sex, and district location (n=27). The data was processed by Chi-Square test._Levels of stress were categorized into two namely high and low tress levels. The data was normally distributed. The frequency distribution in case group at high stress category were 15 respondents (55.6%) and low stress were 12 respondents (44.4%). Meanwhile, in control group there were 8 respondents (29.6%) at high stress category and 19 respondents (70.4%) at low stress category. The Chi Square Test revealed that the p value was 0,054 and OR was 2,969. In conclusion there was no relation between stress level and Dengue Hemorrhagic Fever cases.

A longitudinal investigation of parenting stress in caregivers of children with retinoblastoma.

PubMed

Willard, Victoria W; Qaddoumi, Ibrahim; Zhang, Hui; Huang, Lu; Russell, Kathryn M; Brennan, Rachel; Wilson, Matthew W; Rodriguez-Galindo, Carlos; Phipps, Sean

2017-04-01

Retinoblastoma is typically diagnosed in young children and may present unique parenting challenges. Qualitative research suggests that parents experience distress related to the initial diagnosis and treatment that subsequently resolves. The objectives were to systematically assess parenting stress over time in parents of young children with retinoblastoma and to examine associations between parenting stress and child outcomes. Parents of children with retinoblastoma completed the Parenting Stress Index (PSI) during serial psychological assessments scheduled based on the child's age (6 months to 5 years). Caregivers of 92 patients (85.9% mothers) completed the assessments. Child outcomes included developmental functioning and parent-reported adaptive functioning. At baseline and age 5, all subscales on the PSI were within normal limits, and most were significantly below normative means (i.e., demonstrating low levels of stress). All domains remained relatively stable over time. Associations between parenting stress and child outcomes were much stronger at age 5 than at baseline. Child-directed parenting stress was a small but significant contributor to declines in child functioning over time. Parents of children with retinoblastoma report normal levels of parenting stress while their children are young. However, baseline parenting stress appears to contribute to changes in child functioning over time. Future studies should assess illness-related aspects of adjustment to further understand the parenting experience of young children with cancer and/or having a visually impaired child. © 2016 Wiley Periodicals, Inc.

Effects of emotional and perceptual-motor stress on a voice recognition system's accuracy: An applied investigation

NASA Astrophysics Data System (ADS)

Poock, G. K.; Martin, B. J.

1984-02-01

This was an applied investigation examining the ability of a speech recognition system to recognize speakers' inputs when the speakers were under different stress levels. Subjects were asked to speak to a voice recognition system under three conditions: (1) normal office environment, (2) emotional stress, and (3) perceptual-motor stress. Results indicate a definite relationship between voice recognition system performance and the type of low stress reference patterns used to achieve recognition.

Gene expression of regulatory enzymes of glycolysis/gluconeogenesis in regenerating rat liver.

PubMed Central

Rosa, J L; Bartrons, R; Tauler, A

1992-01-01

Levels of mRNA for glucokinase, L-pyruvate kinase, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase were analysed during liver regeneration. Levels of mRNA for glycolytic enzymes (glucokinase and L-pyruvate kinase) decreased rapidly after partial hepatectomy. Glucokinase mRNA increased at 16-24 h, returning to normal values after this time. L-pyruvate kinase mRNA recovered control levels at 168 h. In contrast, phosphoenolpyruvate carboxykinase mRNA increased rapidly after liver resection and remained high during the regenerative process. However, the levels of fructose-1,6-bisphosphatase mRNA were not modified significantly. These results correlate with the reported increased rate of gluconeogenesis and changes in enzyme levels after partial hepatectomy. The effect of stress on the mRNA levels was also studied. All enzymes showed variations in their mRNA levels after the surgical stress. In general, the differences were more pronounced in regenerating liver than in sham-operated animals, being practically normalized at 24 h. Images Fig. 2. Fig. 3. PMID:1329724

Central neuropeptide Y plays an important role in mediating the adaptation mechanism against chronic stress in male rats.

PubMed

Yang, Yu; Babygirija, Reji; Zheng, Jun; Shi, Bei; Sun, Weinan; Zheng, Xiaojiao; Zhang, Fan; Cao, Yu

2018-02-07

Exposure to continuous life stress often causes gastrointestinal (GI) symptoms. Studies have shown that neuropeptide Y (NPY) counteracts the biological actions of corticotrophin-releasing factor (CRF), and is involved in the termination of the stress response. However, in chronic repeated restraint stress (CRS) conditions, the actions of NPY on GI motility remain controversial. To evaluate the role of NPY in mediation of the adaptation mechanism and GI motility in CRS conditions, a CRS rat model was set up. Central CRF and NPY expression levels were analyzed, serum corticosterone and NPY concentrations were measured, and GI motor function was evaluated. The NPY Y1 receptor antagonist BIBP-3226 was centrally administered before stress loading, and on days, 1-5, of repeated stress, the central CRF and the serum corticosterone concentrations were measured. In addition, gastric and colonic motor functions were evaluated. The elevated central CRF expression and corticosterone concentration caused by acute stress began to fall after 3 days of stress loading, while central NPY expression and serum NPY began to increase. GI dysmotility also returned to a normal level. Pretreatment with BIBP-3226 abolished the adaptation mechanism, and significantly increased CRF expression and the corticosterone concentration, which resulted in delayed gastric emptying and accelerated fecal pellet output. Inhibited gastric motility and enhanced distal colonic motility were also recorded. CRS-produced adaptation, over-expressed central CRF, and GI dysmotility observed in acute restraint stress were restored to normal levels. Central NPY via the Y1 receptor plays an important role in mediating the adaptation mechanism against chronic stress. Copyright © 2018 Endocrine Society.

Effect of housing rats within a pyramid on stress parameters.

PubMed

Bhat, Surekha; Rao, Guruprasad; Murthy, K Dilip; Bhat, P Gopalakrishna

2003-11-01

The Giza pyramids of Egypt have been the subject of much research. Pyramid models with the same base to height ratio as of the Great Pyramid of Giza, when aligned on a true north-south axis, are believed to generate, transform and transmit energy. Research done with such pyramid models has shown that they induced greater relaxation in human subjects, promoted better wound healing in rats and afforded protection against stress-induced neurodegnerative changes in mice. The present study was done to assess the effects of housing Wistar rats within the pyramid on the status of oxidative damage and antioxidant defense in their erythrocytes and cortisol levels in their plasma. Rats were housed in cages under standard laboratory conditions. Cages were left in the open (normal control), under a wooden pyramid model (experimental rats) or in a cubical box of comparable dimensions (6 hr/day for 14 days). Erythrocyte malondialdehyde and plasma cortisol levels were significantly decreased in rats kept within the pyramid as compared to the normal control and those within the square box. Erythrocyte reduced glutathione levels, erythrocyte glutathione peroxidase and superoxide dismutase activities were significantly increased in the rats kept in the pyramid as compared to the other two groups. There was no significant difference in any of the parameters between the normal control and rats kept in the square box. The results showed that exposure of adult female Wistar rats to pyramid environment reduces stress oxidative stress and increases antioxidant defense in them.

Effect of hepatitis B virus infection on sperm quality and oxidative stress state of the semen of infertile males.

PubMed

Qian, Li; Li, Qiong; Li, Haibo

2016-09-01

The effects of hepatitis B virus (HBV) infection on sperm quality and oxidative stress state of the semen of infertile males remain undetermined. Normal males and 60 semen samples from infertile males (with or without HBV infection) were subjected to semen analysis. Semen volume, semen pH, sperm density, percentage of forward, movement of sperm, sperm activation rate, sperm survival rate, rate of normal sperm morphology of infertile males with HBV infection were significantly lower than those of infertile males without genital infection and of normal males (P<.05), while interleukin (IL)-17, IL-18, and malondialdehyde (MDA) levels in subjects with HBV infection were significantly higher than those of infertile males without genital infection and of normal males (P<.05). In patients with HBV infection, MDA level was found to be negatively correlated with semen quality, but positively correlated with semen IL-17 and IL-18 concentrations. HBV infection increased MDA level, induced abnormal expression of IL-17 and IL-18, and negatively affected male reproductive capacity, resulting in male infertility. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Stress and physiological, behavioral and performance patterns of children under varied air ion levels

NASA Astrophysics Data System (ADS)

Fornof, K. T.; Gilbert, G. O.

1988-12-01

The possibility that individual differences in reactivity to stressors are a major factor underlying discordant results reported for air ion studies prompted an investigation of response patterns in school children under both normal indoor air ion levels and moderately increased negative air ion levels (4000±500/cm3). It was hypothesized that the impact of stressors is reduced with high negative air ionization, and that resultant changes in stress effects would be differentially exhibited according to the children's normal degree of stimulus reactivity. A counter-balanced, replicative, withinssubject design was selected, and the subjects were 12 environmentally sensitive, 1st 4th grade school children. In addition to monitoring stress effects on activity level, attention span, concentration to task and conceptual performance, measures were also made of urinary 5-hydroxyindole acetic acid levels and skin resistance response (SRR) to determine if changes extended to the physiological state. The cold water test was used to add physical stress and enable calculations of Lacey's autonomic lability scores (ALS) as indicators of individual reactivity. The results show main effects for air ions on both physiological parameters, with 48% less change in %SRR ( P<0.01) and 46% less change in urinary 5-HIAA levels ( P<0.055) during negative air ions, indicating increased stress tolerance. Strong interactive effects for ALS x air ion condition appeared, with high and low ALS children reacting oppositely to negative air ions in measures of skin resistance level ( P<0.01), wrist activity ( P<0.01) and digit span backwards ( P<0.004). Thus individual differences in autonomic reactivity and the presence or absence of stressors appear as critical elements for internal validity, and in preventing consequent skewed results from obscuring progress in air ion research.

Validation of reference genes for normalization of qPCR mRNA expression levels in Staphylococcus aureus exposed to osmotic and lactic acid stress conditions encountered during food production and preservation.

PubMed

Sihto, Henna-Maria; Tasara, Taurai; Stephan, Roger; Johler, Sophia

2014-07-01

Staphylococcus aureus represents the most prevalent cause of food-borne intoxications worldwide. While being repressed by competing bacteria in most matrices, this pathogen exhibits crucial competitive advantages during growth at high salt concentrations or low pH, conditions frequently encountered in food production and preservation. We aimed to identify reference genes that could be used to normalize qPCR mRNA expression levels during growth of S. aureus in food-related osmotic (NaCl) and acidic (lactic acid) stress adaptation models. Expression stability of nine housekeeping genes was evaluated in full (LB) and nutrient-deficient (CYGP w/o glucose) medium under conditions of osmotic (4.5% NaCl) and acidic stress (lactic acid, pH 6.0) after 2-h exposure. Among the set of candidate reference genes investigated, rplD, rpoB,gyrB, and rho were most stably expressed in LB and thus represent the most suitable reference genes for normalization of qPCR data in osmotic or lactic acid stress models in a rich medium. Under nutrient-deficient conditions, expression of rho and rpoB was highly stable across all tested conditions. The presented comprehensive data on changes in expression of various S. aureus housekeeping genes under conditions of osmotic and lactic acid stress facilitate selection of reference genes for qPCR-based stress response models. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Effect of voluntary wheel running on circadian corticosterone release and on HPA axis responsiveness to restraint stress in Sprague-Dawley rats.

PubMed

Fediuc, Sergiu; Campbell, Jonathan E; Riddell, Michael C

2006-06-01

Adaptations of the hypothalamic-pituitary-adrenal (HPA) axis to voluntary exercise in rodents are not clear, because most investigations use forced-exercise protocols, which are associated with psychological stress. In the present study, we examined the effects of voluntary wheel running on the circadian corticosterone (Cort) rhythm as well as HPA axis responsiveness to, and recovery from, restraint stress. Male Sprague-Dawley rats were divided into exercise (E) and sedentary (S) groups, with E rats having 24-h access to running wheels for 5 wk. Circadian plasma Cort levels were measured at the end of each week, except for week 5 when rats were exposed to 20 min of restraint stress, followed by 95 min of recovery. Measurements of glucocorticoid receptor content in the hippocampus and anterior pituitary were performed using Western blotting at the termination of the restraint protocol. In week 1, circadian Cort levels were twofold higher in E compared with S animals, but the levels progressively decreased in the E group throughout the training protocol to reach similar values observed in S by week 4. During restraint stress and recovery, Cort values were similar between E and S, as was glucocorticoid receptor content in the hippocampus and pituitary gland after death. Compared with E, S animals had higher plasma ACTH levels during restraint. Taken together, these data indicate that 5 wk of wheel running are associated with normal circadian Cort activity and normal negative-feedback inhibition of the HPA axis, as well as with increased adrenal sensitivity to ACTH after restraint stress.

Oxidative Stress, Antioxidant Status and Neurodevelopmental Outcome in Neonates Born to Pre-eclamptic Mothers.

PubMed

Bharadwaj, Shruthi K; Vishnu Bhat, B; Vickneswaran, V; Adhisivam, B; Bobby, Zachariah; Habeebullah, S

2018-05-01

To measure the oxidative stress and antioxidant status in preeclamptic mother-newborn dyads and correlate them with neurodevelopmental outcome at one year of corrected age. This cohort study conducted in a tertiary care teaching hospital, south India included 71 preeclamptic and 72 normal mother-newborn dyads. Biochemical parameters including total antioxidant status (TAS), protein carbonyls and malondialdehyde levels (MDA) were measured in both maternal and cord blood. Infants in both the groups were followed up to one year of corrected age and neurodevelopmental assessment was done using Developmental Assessment Scale for Indian Infants (DASII). Correlation and multivariate regression analysis was done to evaluate the oxidative stress markers in relation to neurodevelopmental outcome. All oxidative stress markers were higher in maternal and cord blood of pre-ecclampsia group compared to the normal group. Maternal Total antioxidant status (M-TAS) was lower in pre-eclampsia group than normal group. More neonates in the pre-ecclampsia group were preterm and intrauterine growth restriction (IUGR) and had higher incidence of morbidities like respiratory distress syndrome (RDS) and early onset sepsis (EOS). Infants in the preeclampsia group had lower motor age, motor score and motor developmental quotient (MoDQ). On multivariate logistic regression analyses, lower M-TAS levels were strongly associated with poor neuro-motor outcomes at 1 y of corrected age. Maternal TAS with a cut-off value of 0.965 mmol/L had a sensitivity of 77.8% and specificity of 55.3% in predicting MoDQ <70 at one year corrected age in infants born to preeclamptic mothers. Oxidative stress is increased in preeclamptic mother-newborn dyads. Low maternal TAS levels are associated with poor neuro-motor outcomes. Maternal TAS in preeclampsia is useful in predicting poor motor development at one year corrected age.

Influence of mental stress on the plasma homocysteine level and blood pressure change in young men.

PubMed

Sawai, Asuka; Ohshige, Kenji; Kura, Naoki; Tochikubo, Osamu

2008-04-01

Objective. This study aimed to determine whether mental stress influences the plasma total homocysteine level or blood pressure in young men. Method. Twenty-seven male university students were assigned to a normal blood pressure group (24-h systolic blood pressure <125 mmHg and diastolic blood pressure <75 mmHg; 13 subjects) or a high blood pressure group (24-h systolic blood pressure > or =125 mmHg, or 24-h diastolic blood pressure > or =75 mmHg; 14 subjects). Wearing an ambulatory blood pressure monitoring device, subjects rested for 30 minutes, underwent an arithmetic test for 15 minutes, and rested again for 15 minutes. Blood samples were taken before and after the test. Plasma total homocysteine levels were measured. Heart rate, blood pressure, and sympathovagal balance were determined during the test. Results. The mean total homocysteine level at rest in the high blood pressure group was slightly, but not significantly, higher than that in the normal blood pressure group. The resting total homocysteine level was significantly higher in subjects with parental history of hypertension than in those without (p < 0.01). Blood pressure, heart rate, and the plasma total homocysteine level were increased significantly by mental stress (p < 0.05). The change in total homocysteine correlated significantly with the changes in systolic blood pressure and sympathovagal balance (p < 0.05). Conclusion. Resting total homocysteine level was significantly higher in male students with a parental history of hypertension than in those without. It was shown that mental stress elevates heart rate, blood pressure, sympathovagal activity, and the plasma total homocysteine level in young men.

Selection of reliable reference genes for quantitative real-time PCR gene expression analysis in Jute (Corchorus capsularis) under stress treatments

PubMed Central

Niu, Xiaoping; Qi, Jianmin; Zhang, Gaoyang; Xu, Jiantang; Tao, Aifen; Fang, Pingping; Su, Jianguang

2015-01-01

To accurately measure gene expression using quantitative reverse transcription PCR (qRT-PCR), reliable reference gene(s) are required for data normalization. Corchorus capsularis, an annual herbaceous fiber crop with predominant biodegradability and renewability, has not been investigated for the stability of reference genes with qRT-PCR. In this study, 11 candidate reference genes were selected and their expression levels were assessed using qRT-PCR. To account for the influence of experimental approach and tissue type, 22 different jute samples were selected from abiotic and biotic stress conditions as well as three different tissue types. The stability of the candidate reference genes was evaluated using geNorm, NormFinder, and BestKeeper programs, and the comprehensive rankings of gene stability were generated by aggregate analysis. For the biotic stress and NaCl stress subsets, ACT7 and RAN were suitable as stable reference genes for gene expression normalization. For the PEG stress subset, UBC, and DnaJ were sufficient for accurate normalization. For the tissues subset, four reference genes TUBβ, UBI, EF1α, and RAN were sufficient for accurate normalization. The selected genes were further validated by comparing expression profiles of WRKY15 in various samples, and two stable reference genes were recommended for accurate normalization of qRT-PCR data. Our results provide researchers with appropriate reference genes for qRT-PCR in C. capsularis, and will facilitate gene expression study under these conditions. PMID:26528312

Delayed degradation of chlorophylls and photosynthetic proteins in Arabidopsis autophagy mutants during stress-induced leaf yellowing

PubMed Central

Sakuraba, Yasuhito; Lee, Sang-Hwa; Kim, Ye-Sol; Park, Ohkmae K.; Hörtensteiner, Stefan; Paek, Nam-Chon

2014-01-01

Plant autophagy, one of the essential proteolysis systems, balances proteome and nutrient levels in cells of the whole plant. Autophagy has been studied by analysing Arabidopsis thaliana autophagy-defective atg mutants, but the relationship between autophagy and chlorophyll (Chl) breakdown during stress-induced leaf yellowing remains unclear. During natural senescence or under abiotic-stress conditions, extensive cell death and early yellowing occurs in the leaves of atg mutants. A new finding is revealed that atg5 and atg7 mutants exhibit a functional stay-green phenotype under mild abiotic-stress conditions, but leaf yellowing proceeds normally in wild-type leaves under these conditions. Under mild salt stress, atg5 leaves retained high levels of Chls and all photosystem proteins and maintained a normal chloroplast structure. Furthermore, a double mutant of atg5 and non-functional stay-green nonyellowing1-1 (atg5 nye1-1) showed a much stronger stay-green phenotype than either single mutant. Taking these results together, it is proposed that autophagy functions in the non-selective catabolism of Chls and photosynthetic proteins during stress-induced leaf yellowing, in addition to the selective degradation of Chl–apoprotein complexes in the chloroplasts through the senescence-induced STAY-GREEN1/NYE1 and Chl catabolic enzymes. PMID:24510943

A critical state model for mudrock behavior at high stress levels

NASA Astrophysics Data System (ADS)

Heidari, M.; Nikolinakou, M. A.; Flemings, P. B.

2016-12-01

Recent experimental work has documented that the compression behavior, friction angle, and lateral stress ratio (k0) of mudrocks vary over the stress range of 1 to 100 MPa. We integrate these observations into a critical state model. The internal friction angle and the slope of the compression curve are key parameters in a mudrock critical state model. Published models assume that these parameters do not depend on the stress level, and hence predict lateral stress and normalized strength ratios that do not change with the stress level. However, recent experimental data on resedimented mudrock samples from Eugene Island, Gulf of Mexico, demonstrate that all these parameters vary considerably with the stress level (Casey and Germaine, 2013; Casey et al., 2015). To represent these variations, we develop an enhanced critical state model that uses a stress-level-dependent friction angle and a curvilinear compression curve. We show that this enhanced model predicts the observed variations of the lateral stress and strength ratios. The successful performance of our model indicates that the critical state theory developed for soil can predict mudrock nonlinear behavior at high stress levels and thus can be used in modeling geologic systems. Casey, B., Germaine, J., 2013. Stress Dependence of Shear Strength in Fine-Grained Soils and Correlations with Liquid Limit. J. Geotech. Geoenviron. Eng. 139, 1709-1717. Casey, B., Germaine, J., Flemings, P.B., Fahy, B.P., 2015. Estimating horizontal stresses for mudrocks under one-dimensional compression. Mar. Pet. Geol. 65, 178-186.

Antibiotic tigecycline enhances cisplatin activity against human hepatocellular carcinoma through inducing mitochondrial dysfunction and oxidative damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jun; Song, Meijun; Zhou, Mi

Targeting mitochondrial metabolism has been recently demonstrated to be a promising therapeutic strategy for the treatment of various cancer. In this work, we demonstrate that antibiotic tigecycline is selectively against hepatocellular carcinoma (HCC) through inducing mitochondrial dysfunction and oxidative damage. Tigecycline is more effective in inhibiting proliferation and inducing apoptosis of HCC than normal liver cells. Importantly, tigecycline significantly enhances the inhibitory effects of chemotherapeutic drug cisplatin in HCC in vitro and in vivo. Mechanistically, tigecycline specifically inhibits mitochondrial translation as shown by the decreased protein levels of Cox-1 and -2 but not Cox-4 or Grp78, and increased mRNA levels of Cox-1more » and -2 but not Cox-4 in HCC cells exposed to tigecycline. In addition, tigecycline significantly induces mitochondrial dysfunction in HCC cells via decreasing mitochondrial membrane potential, complex I and IV activities, mitochondrial respiration and ATP levels. Tigecycline also increases levels of mitochondrial superoxide, hydrogen peroxide and ROS levels. Consistent with oxidative stress, oxidative damage on DNA, protein and lipid are also observed in tigecycline-treated cells. Importantly, antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of tigecycline, suggesting that oxidative stress is required for the action of tigecycline in HCC cells. We further show that HCC cells have higher level of mitochondrial biogenesis than normal liver cells which might explain the different sensitivity to tigecycline between HCC and normal liver cells. Our work is the first to demonstrate that tigecycline is a promising candidate for HCC treatment and highlight the therapeutic value of targeting mitochondrial metabolism in HCC. - Highlights: • Tigecycline selectively targets HCC in vitro and in vivo. • Tigecycline enhances HCC cell response to chemotherapeutic drug. • Tigecycline inhibits mitochondrial translation and functions in HCC cells. • Tigecycline induces oxidative stress and damage in HCC cells. • Mitochondrial biogenesis and respiration is higher in HCC than normal liver cells.« less

Investigation of Thermal Stress Convection in Nonisothermal Gases Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Mackowski, Daniel W.; Knight, Roy W.

1996-01-01

Microgravity conditions offer an environment in which convection in a nonisothermal gas could be driven primarily by thermal stress. A direct examination of thermal stress flows would be invaluable in assessing the accuracy of the Burnett terms in the fluid stress tensor. We present a preliminary numerical investigation of the competing effects of thermal stress, thermal creep at the side walls, and buoyancy on gas convection in nonuniformly heated containers under normal and reduced gravity levels. Conditions in which thermal stress convection becomes dominant are identified, and issues regarding the experimental measurement of the flows are discussed.

Evaluation of Reference Genes for Normalization of Gene Expression Using Quantitative RT-PCR under Aluminum, Cadmium, and Heat Stresses in Soybean.

PubMed

Gao, Mengmeng; Liu, Yaping; Ma, Xiao; Shuai, Qin; Gai, Junyi; Li, Yan

2017-01-01

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is widely used to analyze the relative gene expression level, however, the accuracy of qRT-PCR is greatly affected by the stability of reference genes, which is tissue- and environment- dependent. Therefore, choosing the most stable reference gene in a specific tissue and environment is critical to interpret gene expression patterns. Aluminum (Al), cadmium (Cd), and heat stresses are three important abiotic factors limiting soybean (Glycine max) production in southern China. To identify the suitable reference genes for normalizing the expression levels of target genes by qRT-PCR in soybean response to Al, Cd and heat stresses, we studied the expression stability of ten commonly used housekeeping genes in soybean roots and leaves under these three abiotic stresses, using five approaches, BestKeeper, Delta Ct, geNorm, NormFinder and RefFinder. We found TUA4 is the most stable reference gene in soybean root tips under Al stress. Under Cd stress, Fbox and UKN2 are the most stable reference genes in roots and leaves, respectively, while 60S is the most suitable reference gene when analyzing both roots and leaves together. For heat stress, TUA4 and UKN2 are the most stable housekeeping genes in roots and leaves, respectively, and UKN2 is the best reference gene for analysis of roots and leaves together. To validate the reference genes, we quantified the relative expression levels of six target genes that were involved in soybean response to Al, Cd or heat stresses, respectively. The expression patterns of these target genes differed between using the most and least stable reference genes, suggesting the selection of a suitable reference gene is critical for gene expression studies.

Gibberellins Producing Endophytic Fungus Porostereum spadiceum AGH786 Rescues Growth of Salt Affected Soybean

PubMed Central

Hamayun, Muhammad; Hussain, Anwar; Khan, Sumera A.; Kim, Ho-Youn; Khan, Abdul L.; Waqas, Muhammad; Irshad, Muhammad; Iqbal, Amjad; Rehman, Gauhar; Jan, Samin; Lee, In-Jung

2017-01-01

In the pursuit of sustainable agriculture through environment and human health friendly practices, we evaluated the potential of a novel gibberellins (GAs) producing basidiomycetous endophytic fungus Porostereum spadiceum AGH786, for alleviating salt stress and promoting health benefits of soybean. Soybean seedlings exposed to different levels of NaCl stress (70 and 140 mM) under greenhouse conditions, were inoculated with the AGH786 strain. Levels of phytohormones including GAs, JA and ABA, and isoflavones were compared in control and the inoculated seedlings to understand the mechanism through which the stress is alleviated. Gibberellins producing endophytic fungi have been vital for promoting plant growth under normal and stress conditions. We report P. spadiceum AGH786 as the ever first GAs producing basidiomycetous fungus capable of producing six types of GAs. In comparison to the so for most efficient GAs producing Gibberella fujikuroi, AGH786 produced significantly higher amount of the bioactive GA3. Salt-stressed phenotype of soybean seedlings was characterized by low content of GAs and high amount of ABA and JA with reduced shoot length, biomass, leaf area, chlorophyll contents, and rate of photosynthesis. Mitigation of salt stress by AGH786 was always accompanied by high GAs, and low ABA and JA, suggesting that this endophytic fungus reduces the effect of salinity by modulating endogenous phytohormones of the seedlings. Additionally, this strain also enhanced the endogenous level of two isoflavones including daidzen and genistein in soybean seedlings under normal as well as salt stress conditions as compared to their respective controls. P. spadiceum AGH786 boosted the NaCl stress tolerance and growth in soybean, by modulating seedlings endogenous phytohormones and isoflavones suggesting a valuable contribution of this potent fungal biofertilizer in sustainable agriculture in salt affected soils. PMID:28473818

Effect of psychological distress on weight concern and weight control behaviors.

PubMed

Roohafza, Hamidreza; Kabir, Ali; Sadeghi, Masoumeh; Shokouh, Pedram; Aalaei-Andabili, Seyed Hossein; Mehrabi, Yadollah; Sarrafzadegan, Nizal

2014-09-01

Obesity is associated with chronic disorders like coronary artery diseases, metabolic syndrome, cancers, and psychiatric disorders. Stress may contribute to weight gain by disrupting weight concern, and lead to uncontrolled eating behavior. This study aimed to investigate the effects of stress on weight concern and control behaviors in normal weight and obese adults. A total of 9544 subjects were selected by multi-stage random sampling from three provinces in central Iran. Information related to weight concern and control behavior was registered in normal weight and obese participants. Psychological distress was measured by a 12-item General Health Questionnaire (GHQ-12) and subjects were divided into high and low stress groups. Logistic regression was used for analysis. The mean age of participants was 38.7 ± 15.5 years and 50% (4772) of them were males. The adjusted odds ratio (OR) for age, sex and education of high stress to low stress level for weight concern, weight control behavior and acceptable physical activity behavior was more than 1; but the OR was less than 1 for waist circumference, obesity and healthy diet behavior. Among obese participants, higher levels of stress were associated with lower weight concern with OR, 95%CI: 0.821, (0.682 - 0.988), lower acceptable physical activity with OR = 0.833, 95%CI: (0.624 - 0.912), but higher rates of healthy diet behavior with OR = 1.360, 95% CI: (1.040 - 1.780). Individuals with high stress level have lower weight concern and lower physical activity; therefore, they are prone to weight gain and obesity. It could be concluded that stress management should be considered as a crucial component of obesity prevention and control programs.

8-oxo-7,8-dihydroguanine level - the DNA oxidative stress marker - recognized by fluorescence image analysis in sporadic uterine adenocarcinomas in women.

PubMed

Postawski, Krzysztof; Przadka-Rabaniuk, Dorota; Piersiak, Tomasz

2013-01-01

In the case of carcinogenesis in human endometrium no information exists on tissue concentration of 8-oxo-7,8-dihydroguanine, the DNA oxidative stress marker This was the main reason to undertake the investigation of this DNA modification in human uterine estrogen-dependent tissue cancers. In order to estimate the level of oxidative damage, 8-oxo-7,8-dihydroguanine was determined directly in cells of tissue microscope slides using OxyDNA Assay Kit, Fluorometric. Cells were investigated under confocal microscope. Images of individual cells were captured by computer-interfaced digital photography and analyzed for fluorescence intensities (continuous inverted 8-bit gray-scale = 0 [black]-255 [white]). Fluorescence scores were calculated for each of 13 normal endometrial samples and 31 uterine adenocarcinoma specimens. Finally the level of the oxidative stress marker was also analyzed according to histological and clinical features of the neoplasms. The obtained data revealed that: 8-oxo-7,8-dihydroguanine levels were higher in uterine adenocarcinomas than in normal endometrial samples (48,32 vs. 38,64; p<0,001); in contrast to normal endometrium there was no correlation between age and DNA oxidative modification content in uterine cancer; highest mean fluorescence intensity was recognized in G2 endometrial adenocarcinomas; level of 8-oxo-7,8-dihydroguanine does not depend on Body Mass Index (BMI) and cancer uterine wall infiltration or tumor FIGO stage. Our study indicates that accumulation of the oxidized DNA base may contribute to the development of endometrial neoplasia, however oxidative DNA damage does not seem to increase with tumor progression.

Inhibition of stress-inducible HSP70 impairs mitochondrial proteostasis and function.

PubMed

Leu, Julia I-Ju; Barnoud, Thibaut; Zhang, Gao; Tian, Tian; Wei, Zhi; Herlyn, Meenhard; Murphy, Maureen E; George, Donna L

2017-07-11

Protein quality control is an important component of survival for all cells. The use of proteasome inhibitors for cancer therapy derives from the fact that tumor cells generally exhibit greater levels of proteotoxic stress than do normal cells, and thus cancer cells tend to be more sensitive to proteasome inhibition. However, this approach has been limited in some cases by toxicity to normal cells. Recently, the concept of inhibiting proteostasis in organelles for cancer therapy has been advanced, in part because it is predicted to have reduced toxicity for normal cells. Here we demonstrate that a fraction of the major stress-induced chaperone HSP70 (also called HSPA1A or HSP72, but hereafter HSP70) is abundantly present in mitochondria of tumor cells, but is expressed at quite low or undetectable levels in mitochondria of most normal tissues and non-tumor cell lines. We show that treatment of tumor cells with HSP70 inhibitors causes a marked change in mitochondrial protein quality control, loss of mitochondrial membrane potential, reduced oxygen consumption rate, and loss of ATP production. We identify several nuclear-encoded mitochondrial proteins, including polyadenylate binding protein-1 (PABPC1), which exhibit decreased abundance in mitochondria following treatment with HSP70 inhibitors. We also show that targeting HSP70 function leads to reduced levels of several mitochondrial-encoded RNA species that encode components of the electron transport chain. Our data indicate that small molecule inhibitors of HSP70 represent a new class of organelle proteostasis inhibitors that impair mitochondrial function in cancer cells, and therefore constitute novel therapeutics.

Mechanosensitive channels protect plastids from hypoosmotic stress during normal plant growth.

PubMed

Veley, Kira M; Marshburn, Sarah; Clure, Cara E; Haswell, Elizabeth S

2012-03-06

Cellular response to osmotic stress is critical for survival and involves volume control through the regulated transport of osmolytes. Organelles may respond similarly to abrupt changes in cytoplasmic osmolarity. The plastids of the Arabidopsis thaliana leaf epidermis provide a model system for the study of organellar response to osmotic stress within the context of the cell. An Arabidopsis mutant lacking two plastid-localized homologs of the bacteria mechanosensitive channel MscS (MscS-like [MSL] 2 and 3) exhibits large round epidermal plastids that lack dynamic extensions known as stromules. This phenotype is present under normal growth conditions and does not require exposure to extracellular osmotic stress. Here we show that increasing cytoplasmic osmolarity through a genetic lesion known to produce elevated levels of soluble sugars, exogenously providing osmolytes in the growth media, or withholding water rescues the msl2-1 msl3-1 leaf epidermal plastid phenotype, producing plastids that resemble the wild-type in shape and size. Furthermore, the epidermal plastids in msl2-1 msl3-1 leaves undergo rapid and reversible volume and shape changes in response to extracellular hypertonic or hypotonic challenges. We conclude that plastids are under hypoosmotic stress during normal plant growth and dynamic response to this stress requires MSL2 and MSL3. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of Bauhinia forficata Tea on Oxidative Stress and Liver Damage in Diabetic Mice

PubMed Central

Salgueiro, Andréia Caroline Fernandes; da Silva, Marianne Pires; Mendez, Andreas Sebastian Loureiro; Zemolin, Ana Paula Pegoraro; Posser, Thaís; Puntel, Robson Luiz; Puntel, Gustavo Orione

2016-01-01

This study was designed to evaluate the effects of Bauhinia forficata Link subsp. pruinosa (BF) tea on oxidative stress and liver damage in streptozotocin (STZ)-induced diabetic mice. Diabetic male mice have remained 30 days without any treatment. BF treatment started on day 31 and continued for 21 days as a drinking-water substitute. We evaluated (1) BF chemical composition; (2) glucose levels; (3) liver/body weight ratio and liver transaminases; (4) reactive oxygen species (ROS), lipid peroxidation, and protein carbonylation in liver; (5) superoxide dismutase (SOD) and catalase (CAT) activities in liver; (6) δ-aminolevulinate dehydratase (δ-ALA-D) and nonprotein thiols (NPSH) in liver; (7) Nrf2, NQO-1, and HSP70 levels in liver and pancreas. Phytochemical analyses identified four phenols compounds. Diabetic mice present high levels of NQO-1 in pancreas, increased levels of ROS and lipid peroxidation in liver, and decrease in CAT activity. BF treatment normalized all these parameters. BF did not normalize hyperglycemia, liver/body weight ratio, aspartate aminotransferase, protein carbonyl, NPSH levels, and δ-ALA-D activity. The raised oxidative stress seems to be a potential mechanism involved in liver damage in hyperglycemic conditions. Our results indicated that BF protective effect could be attributed to its antioxidant capacity, more than a hypoglycemic potential. PMID:26839634

Effects of Bauhinia forficata Tea on Oxidative Stress and Liver Damage in Diabetic Mice.

PubMed

Salgueiro, Andréia Caroline Fernandes; Folmer, Vanderlei; da Silva, Marianne Pires; Mendez, Andreas Sebastian Loureiro; Zemolin, Ana Paula Pegoraro; Posser, Thaís; Franco, Jeferson Luis; Puntel, Robson Luiz; Puntel, Gustavo Orione

2016-01-01

This study was designed to evaluate the effects of Bauhinia forficata Link subsp. pruinosa (BF) tea on oxidative stress and liver damage in streptozotocin (STZ)-induced diabetic mice. Diabetic male mice have remained 30 days without any treatment. BF treatment started on day 31 and continued for 21 days as a drinking-water substitute. We evaluated (1) BF chemical composition; (2) glucose levels; (3) liver/body weight ratio and liver transaminases; (4) reactive oxygen species (ROS), lipid peroxidation, and protein carbonylation in liver; (5) superoxide dismutase (SOD) and catalase (CAT) activities in liver; (6) δ-aminolevulinate dehydratase (δ-ALA-D) and nonprotein thiols (NPSH) in liver; (7) Nrf2, NQO-1, and HSP70 levels in liver and pancreas. Phytochemical analyses identified four phenols compounds. Diabetic mice present high levels of NQO-1 in pancreas, increased levels of ROS and lipid peroxidation in liver, and decrease in CAT activity. BF treatment normalized all these parameters. BF did not normalize hyperglycemia, liver/body weight ratio, aspartate aminotransferase, protein carbonyl, NPSH levels, and δ-ALA-D activity. The raised oxidative stress seems to be a potential mechanism involved in liver damage in hyperglycemic conditions. Our results indicated that BF protective effect could be attributed to its antioxidant capacity, more than a hypoglycemic potential.

Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception.

PubMed

Cao, Jing; Wang, Po-Kai; Tiwari, Vinod; Liang, Lingli; Lutz, Brianna Marie; Shieh, Kun-Ruey; Zang, Wei-Dong; Kaufman, Andrew G; Bekker, Alex; Gao, Xiao-Qun; Tao, Yuan-Xiang

2015-12-02

Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. In this study, we showed that pre- or post-surgical exposure to immobilization 6 h daily for three consecutive days did not change basal responses to mechanical, thermal, or cold stimuli or peak levels of incision-induced hypersensitivity to these stimuli; however, immobilization did prolong the duration of incision-induced hypersensitivity in both male and female rats. These phenomena were also observed in post-surgical exposure to forced swimming 25 min daily for 3 consecutive days. Short-term stress induced by immobilization was demonstrated by an elevation in the level of serum corticosterone, an increase in swim immobility, and a decrease in sucrose consumption. Blocking this short-term stress via intrathecal administration of a selective glucocorticoid receptor antagonist, RU38486, or bilateral adrenalectomy significantly attenuated the prolongation of incision-induced hypersensitivity to mechanical, thermal, and cold stimuli. Our results indicate that short-term stress during the pre- or post-operative period delays postoperative pain recovery although it does not affect basal pain perception. Prevention of short-term stress may facilitate patients' recovery from postoperative pain.

Reduction in perceived stress as a migraine trigger

PubMed Central

Lipton, Richard B.; Hall, Charles B.; Tennen, Howard; DeFreitas, Tiffani A.; Borkowski, Thomas M.; Grosberg, Brian M.; Haut, Sheryl R.

2014-01-01

Objective: To test whether level of perceived stress and reductions in levels of perceived stress (i.e., “let-down”) are associated with the onset of migraine attacks in persons with migraine. Methods: Patients with migraine from a tertiary headache center were invited to participate in a 3-month electronic diary study. Participants entered data daily regarding migraine attack experience, subjective stress ratings, and other data. Stress was assessed using 2 measures: the Perceived Stress Scale and the Self-Reported Stress Scale. Logit-normal, random-effects models were used to estimate the odds ratio for migraine occurrence as a function of level of stress over several time frames. Results: Of 22 enrolled participants, 17 (median age 43.8 years) completed >30 days of diaries, yielding 2,011 diary entries including 110 eligible migraine attacks (median 5 attacks per person). Level of stress was not generally associated with migraine occurrence. However, decline in stress from one evening diary to the next was associated with increased migraine onset over the subsequent 6, 12, and 18 hours, with odds ratios ranging from 1.5 to 1.9 (all p values < 0.05) for the Perceived Stress Scale. Decline in stress was associated with migraine onset after controlling for level of stress for all time points. Findings were similar using the Self-Reported Stress Scale. Conclusions: Reduction in stress from one day to the next is associated with migraine onset the next day. Decline in stress may be a marker for an impending migraine attack and may create opportunities for preemptive pharmacologic or behavioral interventions. PMID:24670889

Stress management at the worksite: reversal of symptoms profile and cardiovascular dysregulation.

PubMed

Lucini, Daniela; Riva, Silvano; Pizzinelli, Paolo; Pagani, Massimo

2007-02-01

Work stress may increase cardiovascular risk either indirectly, by inducing unhealthy life styles, or directly, by affecting the autonomic nervous system and arterial pressure. We hypothesized that, before any apparent sign of disease, work-related stress is already accompanied by alterations of RR variability profile and that a simple onsite stress management program based on cognitive restructuring and relaxation training could reduce the level of stress symptoms, revert stress-related autonomic nervous system dysregulation, and lower arterial pressure. We compared 91 white-collar workers, enrolled at a time of work downsizing (hence, in a stress condition), with 79 healthy control subjects. Psychological profiles were assessed by questionnaires and autonomic nervous system regulation by spectral analysis of RR variability. We also tested a simple onsite stress management program (cognitive restructuring and relaxation training) in a subgroup of workers compared with a sham subgroup (sham program). Workers presented an elevated level of stress-related symptoms and an altered variability profile as compared with control subjects (low-frequency component of RR variability was, respectively, 65.2+/-2 versus 55.3+/-2 normalized units; P<0.001; opposite changes were observed for the high-frequency component). These alterations were largely reverted (low-frequency component of RR variability from 63.6+/-3.9 to 49.3+/-3 normalized units; P<0.001) by the stress management program, which also slightly lowered systolic arterial pressure. No changes were observed in the sham program group. This noninvasive study indicates that work stress is associated with unpleasant symptoms and with an altered autonomic profile and suggests that a stress management program could be implemented at the worksite, with possible preventive advantages for hypertension.

Low serum uric acid levels in chronic insomnia patients: A case-control study.

PubMed

Zhao, Kai; Luan, Xiaoqian; Liu, Zhihua; Zhu, Zhuoying; Chen, Huijun; Shen, Huiping; Cai, Yan; Qiu, Huihua; Wang, Qiongzhang; Gu, Yingying; Zhu, Lin; He, Jincai

2017-09-14

Recent studies have demonstrated the presence of oxidative stress in insomnia patients. Uric acid (UA) is regarded as one of the most important antioxidants that may attenuate oxidative stress. The aim of our study was to investigate whether there is an alteration of serum UA levels in chronic insomnia patients. The association between sleep quality and serum UA in chronic insomnia patients was also investigated. We recruited 300 chronic insomnia patients and 300 age- and gender-matched normal controls. The uricase-PAP method was used to measure the concentration of UA both in patient and normal control subjects. The Pittsburgh Sleep Quality Index (PSQI) was used to assess the sleep quality of chronic insomniac participants. As a result, significantly lower serum UA levels were observed in patients with chronic insomnia when compared with normal control subjects (279.56±65.80 vs. 299.10±61.17μmol/L, t=-3.991, p<0.001). Low serum UA levels were correlated with high PSQI scores in multiple linear regression models (β=-0.322, p<0.001). Our results suggested that low serum UA levels were associated with the presence and severity of chronic insomnia. Copyright © 2017 Elsevier B.V. All rights reserved.

A Statistical Perspective on Highly Accelerated Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Edward V.

Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use ofmore » highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning the assumed relationship between the stress level and performance. In addition, this document contains recommendations for conducting more informative accelerated tests.« less

Clinical risk factors demonstrate an age-dependent relationship with oxidative stress biomarkers in African Americans.

PubMed

Sturgeon, Kathleen M; Feairheller, Deborah L; Diaz, Keith M; Williamson, Sheara T; Veerabhadrappa, Praveen; Brown, Michael D

2010-01-01

To examine the interaction of oxidative stress biomarkers with age, and also factors that influence oxidative stress such as body mass index (BMI) and fitness in a population of individuals with established higher risk of cardiovascular disease, African Americans. Blood samples were obtained from healthy college-age and middle-age to older African Americans. Participants underwent a graded exercise test. Superoxide dismutase (SOD) activity, total antioxidant capacity and thiobarbituric acid reactive substances (TBARS) levels were measured. TBARS levels were significantly (P = .001) lower in young participants relative to middle-age to older participants. SOD activity was significantly (P = .001) lower in middle-age to older participants with low fitness relative to participants with normal fitness, and lower (P = .04) in middle-age to older participants that were overweight relative to normal weight participants. In a healthy middle-age to older population of African Americans, BMI and fitness are crucial for maintaining a healthy endothelium.

Frictional response of simulated faults to normal stresses perturbations probed with ultrasonic waves

NASA Astrophysics Data System (ADS)

Shreedharan, S.; Riviere, J.; Marone, C.

2017-12-01

We report on a suite of laboratory friction experiments conducted on saw-cut Westerly Granite surfaces to probe frictional response to step changes in normal stress and loading rate. The experiments are conducted to illuminate the fundamental processes that yield friction rate and state dependence. We quantify the microphysical frictional response of the simulated fault surfaces to normal stress steps, in the range of 1% - 600% step increases and decreases from a nominal baseline normal stress. We measure directly the fault slip rate and account for changes in slip rate with changes in normal stress and complement mechanical data acquisition by continuously probing the faults with ultrasonic pulses. We conduct the experiments at room temperature and humidity conditions in a servo controlled biaxial testing apparatus in the double direct shear configuration. The samples are sheared over a range of velocities, from 0.02 - 100 μm/s. We report observations of a transient shear stress and friction evolution with step increases and decreases in normal stress. Specifically, we show that, at low shear velocities and small increases in normal stress (<5% increase), the shear stress on the fault does not increase instantaneously with the normal stress step while the ultrasonic wave amplitude and normal displacement do. In other words, the shear stress does not follow the load point stiffness curve. At high shear velocities and larger normal stress steps (> 5% increases), the shear stress evolves immediately with normal stress. We show that the excursions in slip rate resulting from the changes in normal stress must be accounted for in order to predict fault strength evolution. Ultrasonic wave amplitudes which first increase immediately in response to normal stress steps, then decrease approximately linearly to a new steady state value, in part due to changes in fault slip rate. Previous descriptions of frictional state evolution during normal stress perturbations have not adequately accounted for the effect of large slip velocity excursions. Here, we attempt to do so by using the measured ultrasonic amplitudes as a proxy for frictional state during transient shear stress evolution. Our work aims to improve understanding of induced and triggered seismicity with focus on simulating static triggering using rate and state friction.

Evaluating Heavy Metal Stress Levels in Rice Based on Remote Sensing Phenology.

PubMed

Liu, Tianjiao; Liu, Xiangnan; Liu, Meiling; Wu, Ling

2018-03-14

Heavy metal pollution of croplands is a major environmental problem worldwide. Methods for accurately and quickly monitoring heavy metal stress have important practical significance. Many studies have explored heavy metal stress in rice in relation to physiological function or physiological factors, but few studies have considered phenology, which can be sensitive to heavy metal stress. In this study, we used an integrated Normalized Difference Vegetation Index (NDVI) time-series image set to extract remote sensing phenology. A phenological indicator relatively sensitive to heavy metal stress was chosen from the obtained phenological periods and phenological parameters. The Dry Weight of Roots (WRT), which directly affected by heavy metal stress, was simulated by the World Food Study (WOFOST) model; then, a feature space based on the phenological indicator and WRT was established for monitoring heavy metal stress. The results indicated that the feature space can distinguish the heavy metal stress levels in rice, with accuracy greater than 95% for distinguishing the severe stress level. This finding provides scientific evidence for combining rice phenology and physiological characteristics in time and space, and the method is useful to monitor heavy metal stress in rice.

The interplay of stress and sleep impacts BDNF level.

PubMed

Giese, Maria; Unternaehrer, Eva; Brand, Serge; Calabrese, Pasquale; Holsboer-Trachsler, Edith; Eckert, Anne

2013-01-01

Sleep plays a pivotal role in normal biological functions. Sleep loss results in higher stress vulnerability and is often found in mental disorders. There is evidence that brain-derived neurotrophic factor (BDNF) could be a central player in this relationship. Recently, we could demonstrate that subjects suffering from current symptoms of insomnia exhibited significantly decreased serum BDNF levels compared with sleep-healthy controls. In accordance with the paradigm indicating a link between sleep and BDNF, we aimed to investigate if the stress system influences the association between sleep and BDNF. Participants with current symptoms of insomnia plus a former diagnosis of Restless Legs Syndrome (RLS) and/or Periodic Limb Movement (PLM) and sleep healthy controls were included in the study. They completed questionnaires on sleep (ISI, Insomnia Severity Index) and stress (PSS, Perceived Stress Scale) and provided a blood sample for determination of serum BDNF. We found a significant interaction between stress and insomnia with an impact on serum BDNF levels. Moreover, insomnia severity groups and score on the PSS each revealed a significant main effect on serum BDNF levels. Insomnia severity was associated with increased stress experience affecting serum BDNF levels. Of note, the association between stress and BDNF was only observed in subjects without insomnia. Using a mediation model, sleep was revealed as a mediator of the association between stress experience and serum BDNF levels. This is the first study to show that the interplay between stress and sleep impacts BDNF levels, suggesting an important role of this relationship in the pathogenesis of stress-associated mental disorders. Hence, we suggest sleep as a key mediator at the connection between stress and BDNF. Whether sleep is maintained or disturbed might explain why some individuals are able to handle a certain stress load while others develop a mental disorder.

Sustaining hypercitrullinemia, hypercholesterolemia and augmented oxidative stress in Japanese children with aspartate/glutamate carrier isoform 2-citrin-deficiency even during the silent period.

PubMed

Nagasaka, Hironori; Okano, Yoshiyuki; Tsukahara, Hirokazu; Shigematsu, Yosuke; Momoi, Toru; Yorifuji, Junko; Miida, Takashi; Ohura, Toshihiro; Kobayashi, Keiko; Saheki, Takeyori; Hirano, Kenichi; Takayanagi, Masaki; Yorifuji, Tohru

2009-05-01

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) shows diverse metabolic abnormalities such as urea cycle dysfunction together with citrullinemia, galactosemia, and suppressed gluconeogenesis. Such abnormalities apparently resolve during the first year of life. However, metabolic profiles of the silent period remain unknown. We analyzed oxidative stress markers and profiles of amino acids, carbohydrates, and lipids in 20 asymptomatic children with aspartate/glutamate carrier isoform 2-citrin-deficiency aged 1-10 years, for whom tests showed normal liver function. Despite normal plasma ammonia levels, the affected children showed higher blood levels of ornithine (p<0.001) and citrulline (p<0.01)--amino acids involved in the urea cycle--than healthy children. Blood levels of nitrite/nitrate, metabolites of nitric oxide (NO), and asymmetric dimethylarginine inhibiting NO production from arginine were not different between these two groups. Blood glucose, galactose, pyruvate, and lactate levels after 4-5h fasting were not different between these groups, but the affected group showed a significantly higher lactate to pyruvate ratio. Low-density and high-density lipoprotein cholesterol levels in the affected group were 1.5 times higher than those in the controls. Plasma oxidized low-density lipoprotein apparently increased in the affected children; their levels of urinary oxidative stress markers such as 8-hydroxy-2'-deoxyguanosine and acrolein-lysine were significantly higher than those in the controls. Results of this study showed, even during the silent period, sustained hypercitrullinemia, hypercholesterolemia, and augmented oxidative stress in children with citrin deficiency.

Astressin B, a corticotropin-releasing hormone receptor antagonist, accelerates the return to normal luteal function after an inflammatory-like stress challenge in the rhesus monkey.

PubMed

Xiao, Ennian; Xia-Zhang, Linna; Vulliemoz, Nicolas; Rivier, Jean; Ferin, Michel

2007-02-01

Endogenous release of CRH in stress has been associated with a dysfunctional reproductive endocrine axis. In the rhesus monkey, an inflammatory-like stress challenge in the luteal phase decreases luteal secretory function. Here, we tested the effectiveness of astressin B, a nonspecific CRH receptor antagonist, in constraining the deleterious impact of a 10-d lipopolysaccharide (LPS) challenge on the menstrual cycle. Two protocols were carried out in nine animals. In the first, the animals, after showing two normal consecutive control cycles, were injected daily for 10 days with LPS (75-125 mug/d) during the luteal phase of the cycle. The animals were followed through the two postchallenge cycles. The second protocol, carried out in the following year, was identical with protocol 1, except that the animals were treated with astressin B (0.45 mg/kg) 1 h before each daily LPS challenge during the luteal phase. Blood samples were obtained daily to document cyclic hormones levels. The LPS challenge significantly decreased luteal progesterone and LH release during the challenge cycle. Inhibition of luteal progesterone extended to the two successive postchallenge cycles. Astressin B treatment prevented luteal LH but not luteal progesterone decrease during the treatment cycle and restored normal progesterone secretion during the two posttreatment cycles. We conclude that the deleterious impact of a short-term inflammatory stress challenge on luteal function is far longer than the stress period itself. Systemic administration of astressin B accelerates the return to normal luteal function, presumably by restoring normal neuroendocrine regulation of gonadotropin secretion.

Using RNA-seq to Profile Gene Expression of Spikelet Development in Response to Temperature and Nitrogen during Meiosis in Rice (Oryza sativa L.).

PubMed

Yang, Jun; Chen, Xiaorong; Zhu, Changlan; Peng, Xiaosong; He, Xiaopeng; Fu, Junru; Ouyang, Linjuan; Bian, Jianmin; Hu, Lifang; Sun, Xiaotang; Xu, Jie; He, Haohua

2015-01-01

Rice reproductive development is sensitive to high temperature and soil nitrogen supply, both of which are predicted to be increased threats to rice crop yield. Rice spikelet development is a critical process that determines yield, yet little is known about the transcriptional regulation of rice spikelet development in response to the combination of heat stress and low nitrogen availability. Here, we profiled gene expression of rice spikelet development during meiosis under heat stress and different nitrogen levels using RNA-seq. We subjected plants to four treatments: 1) NN: normal nitrogen level (165 kg ha-1) with normal temperature (30°C); 2) HH: high nitrogen level (264 kg ha-1) with high temperature (37°C); 3) NH: normal nitrogen level and high temperature; and 4) HN: high nitrogen level and normal temperature. The de novo transcriptome assembly resulted in 52,250,482 clean reads aligned with 76,103 unigenes, which were then used to compare differentially expressed genes (DEGs) in the different treatments. Comparing gene expression in samples with the same nitrogen levels but different temperatures, we identified 70 temperature-responsive DEGs in normal nitrogen levels (NN vs NH) and 135 DEGs in high nitrogen levels (HN vs HH), with 27 overlapping DEGs. We identified 17 and seven nitrogen-responsive DEGs by comparing changes in nitrogen levels in lower temperature (NN vs HN) and higher temperature (NH vs HH), with one common DEG. The temperature-responsive genes were principally associated with cytochrome, heat shock protein, peroxidase, and ubiquitin, while the nitrogen-responsive genes were mainly involved in glutamine synthetase, amino acid transporter, pollen development, and plant hormone. Rice spikelet fertility was significantly reduced under high temperature, but less reduced under high-nitrogen treatment. In the high temperature treatments, we observed downregulation of genes involved in spikelet development, such as pollen tube growth, pollen maturation, especially sporopollenin biosynthetic process, and pollen exine formation. Moreover, we observed higher expression levels of the co-expressed DEGs in HN vs HH compared to NN vs NH. These included the six downregulated genes (one pollen maturation and five pollen exine formation genes), as well as the four upregulated DEGs in response to heat. This suggests that high-nitrogen treatment may enhance the gene expression levels to mitigate aspects of heat-stress. The spikelet genes identified in this study may play important roles in response to the combined effects of high temperature and high nitrogen, and may serve as candidates for crop improvement.

Normal Stress or Adjustment Disorder?

MedlinePlus

... Lifestyle Stress management What's the difference between normal stress and an adjustment disorder? Answers from Daniel K. Hall-Flavin, M.D. Stress is a normal psychological and physical reaction to ...

The burden of online friends: the effects of giving up Facebook on stress and well-being.

PubMed

Vanman, Eric J; Baker, Rosemary; Tobin, Stephanie J

2018-01-01

People occasionally choose to cut themselves off from their online social network by taking extended breaks from Facebook. This study investigated whether abstaining from Facebook reduces stress but also reduces subjective well-being because of the resulting social disconnection. Participants (138 active Facebook users) were assigned to either a condition in which they were instructed to give up Facebook for 5 days or continue to use Facebook as normal. Perceived stress and well-being, as well as salivary cortisol, were measured before and after the test period. Relative to those in the Facebook Normal condition, those in the No Facebook condition experienced lower levels of cortisol and life satisfaction. Our results suggest that the typical Facebook user may occasionally find the large amount of social information available to be taxing, and Facebook vacations could ameliorate this stress-at least in the short term.

MECHANISMS IN ENDOCRINOLOGY: Nutrition as a mediator of oxidative stress in metabolic and reproductive disorders in women.

PubMed

Diamanti-Kandarakis, Evanthia; Papalou, Olga; Kandaraki, Eleni A; Kassi, Georgia

2017-02-01

Nutrition can generate oxidative stress and trigger a cascade of molecular events that can disrupt oxidative and hormonal balance. Nutrient ingestion promotes a major inflammatory and oxidative response at the cellular level in the postprandial state, altering the metabolic state of tissues. A domino of unfavorable metabolic changes is orchestrated in the main metabolic organs, including adipose tissue, skeletal muscle, liver and pancreas, where subclinical inflammation, endothelial dysfunction, mitochondrial deregulation and impaired insulin response and secretion take place. Simultaneously, in reproductive tissues, nutrition-induced oxidative stress can potentially violate delicate oxidative balance that is mandatory to secure normal reproductive function. Taken all the above into account, nutrition and its accompanying postprandial oxidative stress, in the unique context of female hormonal background, can potentially compromise normal metabolic and reproductive functions in women and may act as an active mediator of various metabolic and reproductive disorders. © 2017 European Society of Endocrinology.

An analytical and experimental study of crack extension in center-notched composites

NASA Technical Reports Server (NTRS)

Beuth, Jack L., Jr.; Herakovich, Carl T.

1987-01-01

The normal stress ratio theory for crack extension in anisotropic materials is studied analytically and experimentally. The theory is applied within a microscopic-level analysis of a single center notch of arbitrary orientation in a unidirectional composite material. The bulk of the analytical work of this study applies an elasticity solution for an infinite plate with a center line to obtain critical stress and crack growth direction predictions. An elasticity solution for an infinite plate with a center elliptical flaw is also used to obtain qualitative predictions of the location of crack initiation on the border of a rounded notch tip. The analytical portion of the study includes the formulation of a new crack growth theory that includes local shear stress. Normal stress ratio theory predictions are obtained for notched unidirectional tensile coupons and unidirectional Iosipescu shear specimens. These predictions are subsequently compared to experimental results.

Normalized coffin-manson plot in terms of a new life function based on stress relaxation under creep-fatigue conditions

NASA Astrophysics Data System (ADS)

Jeong, Chang Yeol; Nam, Soo Woo; Lim, Jong Dae

2003-04-01

A new life prediction function based on a model formulated in terms of stress relaxation during hold time under creep-fatigue conditions is proposed. From the idea that reduction in fatigue life with hold is due to the creep effect of stress relaxation that results in additional energy dissipation in the hysteresis loop, it is suggested that the relaxed stress range may be a creep-fatigue damage function. Creep-fatigue data from the present and other investigators are used to check the validity of the proposed life prediction equation. It is shown that the data satisfy the applicability of the life relation model. Accordingly, using this life prediction model, one may realize that all the Coffin-Manson plots at various levels of hold time in strain-controlled creep-fatigue tests can be normalized to make one straight line.

Salt and nitric oxide synthase inhibition-induced hypertension: kidney dysfunction and brain anti-oxidant capacity.

PubMed

Oktar, Süleyman; Ilhan, Selçuk; Meydan, Sedat; Aydin, Mehmet; Yönden, Zafer; Gökçe, Ahmet

2010-01-01

The specific aim of this study was to examine the effects of salt-loading on kidney function and brain antioxidant capacity. Wistar rats were divided into four groups: Control rats were given normal drinking water and no drug treatment for 2 weeks. LNNA group: rats were given normal drinking water and the nitric oxide (NO) inhibitor NG-nitro-L-arginine (L-NNA), 3 mg/kg/day. LNNA + Salt group: rats were given drinking water containing salt 2% and 3 mg/kg L-NNA. Salt group: rats were given drinking water containing salt 2% and no drug treatment. Basal blood pressure and the levels of serum BUN, creatinine, uric acid, cortisol, electrolyte, serum antioxidant capacity, and oxidative stress were measured. NO, superoxide dismutase (SOD), and catalase (CAT) levels were measured in the hypothalamus, brainstem, and cerebellum. Salt overload increased the blood pressure of the LNNA + Salt group. Salt-loading enhanced BUN, creatinine, sodium retention. High salt produced an increase in uric acid levels and a decrease in cortisol levels in serum. Additionally, the oxidative stress index in serum increased in the LNNA + Salt group. Salt-loading enhanced brain NO levels, but not SOD and CAT activity. L-NNA increased brain SOD activity, but not CAT and NO levels. In conclusion, salt-loading causes hypertension, kidney dysfunction, and enhances oxidative stress in salt-sensitive rats.

Use of a student support group to reduce student stress in a nurse anesthesia program.

PubMed

Kless, J R

1989-02-01

Stress in nurse anesthesia programs may be excessive at times, especially in new students. While some degree of stress is necessary to motivate learning, excessive or prolonged stress can interfere with the normal learning process, thereby prolonging a student's clinical and academic progress. In the extreme, excessive stress may even preclude a student's successful completion of the educational program. Active faculty intervention through a student support group is advocated as a method for controlling stress levels and facilitating student learning. The positive effects of such intervention also increase the overall productivity of a program and better prepare nurse anesthesia students for their future careers.

Disrupted autophagy after spinal cord injury is associated with ER stress and neuronal cell death

PubMed Central

Liu, S; Sarkar, C; Dinizo, M; Faden, A I; Koh, E Y; Lipinski, M M; Wu, J

2015-01-01

Autophagy is a catabolic mechanism facilitating degradation of cytoplasmic proteins and organelles in a lysosome-dependent manner. Autophagy flux is necessary for normal neuronal homeostasis and its dysfunction contributes to neuronal cell death in several neurodegenerative diseases. Elevated autophagy has been reported after spinal cord injury (SCI); however, its mechanism, cell type specificity and relationship to cell death are unknown. Using a rat model of contusive SCI, we observed accumulation of LC3-II-positive autophagosomes starting at posttrauma day 1. This was accompanied by a pronounced accumulation of autophagy substrate protein p62, indicating that early elevation of autophagy markers reflected disrupted autophagosome degradation. Levels of lysosomal protease cathepsin D and numbers of cathepsin-D-positive lysosomes were also decreased at this time, suggesting that lysosomal damage may contribute to the observed defect in autophagy flux. Normalization of p62 levels started by day 7 after SCI, and was associated with increased cathepsin D levels. At day 1 after SCI, accumulation of autophagosomes was pronounced in ventral horn motor neurons and dorsal column oligodendrocytes and microglia. In motor neurons, disruption of autophagy strongly correlated with evidence of endoplasmic reticulum (ER) stress. As autophagy is thought to protect against ER stress, its disruption after SCI could contribute to ER-stress-induced neuronal apoptosis. Consistently, motor neurons showing disrupted autophagy co-expressed ER-stress-associated initiator caspase 12 and cleaved executioner caspase 3. Together, these findings indicate that SCI causes lysosomal dysfunction that contributes to autophagy disruption and associated ER-stress-induced neuronal apoptosis. PMID:25569099

The cortisol level and its relationship with depression, stress and anxiety indices in chronic methamphetamine-dependent patients and normal individuals undergoing inguinal hernia surgery.

PubMed

Pirnia, Bijan; Givi, Fatemeh; Roshan, Rasool; Pirnia, Kambiz; Soleimani, Ali Akbar

2016-01-01

Stimulants addition and abuse can cause some functional and morphological changes in the normal function of glands and hormones. Methamphetamine as an addictive stimulant drug affects the Hypothalamic- pituitary-adrenal (HPA) axis and consequently makes some changes in the psychological state of the drug users. The present study aims to examine the relationship between plasma levels of cortisol with depression, stress and anxiety symptoms in chronic methamphetamine-dependent patients and normal individuals who have undergone the inguinal hernia surgery. To meet the purpose of the study, 35 chronic methamphetamine-dependent patients in the active phase of drug abuse and 35 non-users (N=70) who were homogenized regarding the demographic features were purposefully selected from among the patients referred to undergo inguinal hernia surgery since March 15 to June 9, 2015. The participants were then divided into the control and experiment group. The changes in cortisol levels in plasma were measured using Radioimmunoassay (RIA) in three-time series including 0 (upon the induction of anesthesia), 12 and 24 hours after the surgery. Further, three behavioral indices of depression, anxiety and stress were measured using the Depression Anxiety Stress Scale 21 (DASS-21) and then the data were analyzed using t-test and Pearson Correlation coefficient. The plasma level of cortisol in the chronic methamphetamine-dependent patients (experiment group) had a significant increase in 24 hours after surgery (p<0.05). This study showed that cortisol levels in chronic methamphetamine-dependent patients were significantly higher than non-dependent patients in response to alarming events such as inguinal surgery. Changes in cortisol levels were intensified due to a confrontation with the phenomenon of pain and anxiety. In addition, depression index was higher in the chronic methamphetaminedependent patients than that in the non-dependent patients. However, there was no significant relationship between the cortisol level and depression index (p=0.001). The Hypothalamic-pituitary-adrenal (HPA) axis is considered as a key structure in the addiction to simulants, the reason which can explain the faster response of the chronic methamphetamine-dependent patients to the stressors such as surgery.

Effect of long-term stress on H3Ser10 histone phosphorylation in neuronal nuclei of the sensorimotor cortex and midbrain reticular formation in rats with different nervous system excitability.

PubMed

Pavlova, M B; Dyuzhikova, N A; Shiryaeva, N V; Savenko, Yu N; Vaido, A I

2013-07-01

The effects of long-term mental and pain stress on H3Ser10 histone phosphorylation in neurons of the the sensorimotor corex and midbrain reticular formation were studied 24 h, 2 weeks, and 2 months after exposure of rats differing by the nervous system excitability. Rats with high excitability threshold exhibited higher basal level of H3Ser10 histone phosphorylation in the midbrain reticular formation neurons than rats with low excitability threshold. The sensorimotor cortical neurons of the two strains did not differ by this parameter. Stress led to a significant increase in the counts of immunopositive neuronal nuclei in rats with low excitability threshold: the parameter increased significantly in the sensorimotor cortex 24 h after exposure and normalized in 2 weeks after neurotization. In the midbrain reticular formation of this rat strain stress stimulated H3Ser10 histone phosphorylation after 24 h and after 2 weeks; the parameter normalized after neurotization in 2 months. Hence, genetically determined level of the nervous system excitability was essential for the basal level of neuron phosphorylation and for the time course of this process after long-term exposure to mental and pain stress, depending on the brain structure. A probable relationship between H3Ser10 histone phosphorylation process and liability to obsessive compulsive mental disorders in humans was discussed.

Cardiovascular effects of variations in habitual levels of physical activity

NASA Technical Reports Server (NTRS)

Blomqvist, C. G.; Mitchell, J. H.

1975-01-01

Mechanisms involved in human cardiovascular adaption to stress, particularly adaption to different levels of physical activity are determined along with quantitative noninvasive methods for evaluation of cardiovascular function during stess in normal subjects and in individuals with latent or manifest cardiovascular disease. Results are summarized.

Environmental Enrichment Effect on Fecal Glucocorticoid Metabolites and Captive Maned Wolf (Chrysocyon brachyurus) Behavior.

PubMed

Coelho, Carlyle Mendes; de Azevedo, Cristiano Schetini; Guimarães, Marcelo Alcino de Barros Vaz; Young, Robert John

2016-01-01

Environmental enrichment is a technique that may reduce the stress of nonhuman animals in captivity. Stress may interfere with normal behavioral expression and affect cognitive decision making. Noninvasive hormonal studies can provide important information about the stress statuses of animals. This study evaluated the effectiveness of different environmental enrichment treatments in the diminution of fecal glucocorticoid metabolites (stress indicators) of three captive maned wolves (Chrysocyon brachyurus). Correlations of the fecal glucocorticoid metabolite levels with expressed behaviors were also determined. Results showed that environmental enrichment reduced fecal glucocorticoid metabolite levels. Furthermore, interspecific and foraging enrichment items were most effective in reducing stress in two of the three wolves. No definite pattern was found between behavioral and physiological responses to stress. In conclusion, these behavioral and physiological data showed that maned wolves responded positively from an animal well being perspective to the enrichment items presented.

On factors controlling precursor slip fronts in the laboratory and their relation to slow slip events in nature

NASA Astrophysics Data System (ADS)

Selvadurai, Paul A.; Glaser, Steven D.; Parker, Jessica M.

2017-03-01

Spatial variations in frictional properties on natural faults are believed to be a factor influencing the presence of slow slip events (SSEs). This effect was tested on a laboratory frictional interface between two polymethyl methacrylate (PMMA) bodies. We studied the evolution of slip and slip rates that varied systematically based on the application of both high and low normal stress (σ0=0.8 or 0.4 MPa) and the far-field loading rate (VLP). A spontaneous, frictional rupture expanded from the central, weaker, and more compliant section of the fault that had fewer asperities. Slow rupture propagated at speeds Vslow˜0.8 to 26 mm s-1 with slip rates from 0.01 to 0.2 μm s-1, resulting in stress drops around 100 kPa. During certain nucleation sequences, the fault experienced a partial stress drop, referred to as precursor detachment fronts in tribology. Only at the higher level of normal stress did these fronts exist, and the slip and slip rates mimicked the moment and moment release rates during the 2013-2014 Boso SSE in Japan. The laboratory detachment fronts showed rupture propagation speeds Vslow/VR∈ (5 to 172) × 10-7 and stress drops ˜ 100 kPa, which both scaled to the aforementioned SSE. Distributions of asperities, measured using a pressure sensitive film, increased in complexity with additional normal stress—an increase in normal stress caused added complexity by increasing both the mean size and standard deviation of asperity distributions, and this appeared to control the presence of the detachment front.

Gastroprotective Properties of Karanjin from Karanja (Pongamia pinnata) Seeds; Role as Antioxidant and H, K-ATPase Inhibitor.

PubMed

Vismaya; Belagihally, Srikanta M; Rajashekhar, Sindhu; Jayaram, Vinay B; Dharmesh, Shylaja M; Thirumakudalu, Sindhu Kanya C

2011-01-01

Plant extracts are the most attractive sources of newer drugs and have been shown to produce promising results for the treatment of gastric ulcers. Karanjin, a furano-flavonoid has been evaluated for anti-ulcerogenic property by employing adult male albino rats. Karanjin (>95% pure) was administered to these rats in two different concentrations, that is, 10 and 20 mg kg(-1) b.w. Ulcers were induced in the experimental animals by swim and ethanol stress. Serum, stomach and liver-tissue homogenates were assessed for biochemical parameters. Karanjin inhibited 50 and 74% of ulcers induced by swim stress at 10 and 20 mg kg(-1) b.w., respectively. Gastric mucin was protected up to 85% in case of swim stress, whereas only 47% mucin recovery was seen in ethanol stress induced ulcers. H(+), K(+)-ATPase activity, which was increased 2-fold in ulcer conditions, was normalized by Karanjin in both swim/ethanol stress-induced ulcer models. Karanjin could inhibit oxidative stress as evidenced by the normalization of lipid peroxidation and antioxidant enzyme (i.e., catalase, peroxidase and superoxide dismutase) levels. Karanjin at concentrations of 20 mg kg(-1) b.w., when administered orally for 14 days, did not indicate any lethal effects. There were no significant differences in total protein, serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase and alkaline phosphatase between normal and Karanjin-treated rats indicating no adverse effect on major organs. During treatment schedule, animals remained as healthy as control animals with normal food and water intake and body weight gain.

Gastroprotective Properties of Karanjin from Karanja (Pongamia pinnata) Seeds; Role as Antioxidant and H+, K+-ATPase Inhibitor

PubMed Central

Vismaya; Belagihally, Srikanta M.; Rajashekhar, Sindhu; Jayaram, Vinay B.; Dharmesh, Shylaja M.; Thirumakudalu, Sindhu Kanya C.

2011-01-01

Plant extracts are the most attractive sources of newer drugs and have been shown to produce promising results for the treatment of gastric ulcers. Karanjin, a furano-flavonoid has been evaluated for anti-ulcerogenic property by employing adult male albino rats. Karanjin (>95% pure) was administered to these rats in two different concentrations, that is, 10 and 20 mg kg−1 b.w. Ulcers were induced in the experimental animals by swim and ethanol stress. Serum, stomach and liver-tissue homogenates were assessed for biochemical parameters. Karanjin inhibited 50 and 74% of ulcers induced by swim stress at 10 and 20 mg kg−1 b.w., respectively. Gastric mucin was protected up to 85% in case of swim stress, whereas only 47% mucin recovery was seen in ethanol stress induced ulcers. H+, K+-ATPase activity, which was increased 2-fold in ulcer conditions, was normalized by Karanjin in both swim/ethanol stress-induced ulcer models. Karanjin could inhibit oxidative stress as evidenced by the normalization of lipid peroxidation and antioxidant enzyme (i.e., catalase, peroxidase and superoxide dismutase) levels. Karanjin at concentrations of 20 mg kg−1 b.w., when administered orally for 14 days, did not indicate any lethal effects. There were no significant differences in total protein, serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase and alkaline phosphatase between normal and Karanjin-treated rats indicating no adverse effect on major organs. During treatment schedule, animals remained as healthy as control animals with normal food and water intake and body weight gain. PMID:21799691

High-fat diet effects on metabolic responses to chronic stress.

PubMed

Nemati, Marzieh; Zardooz, Homeira; Rostamkhani, Fatemeh; Abadi, Alireza; Foroughi, Forough

2017-07-01

High-fat diets and chronic stress are prevalent risk factors for various chronic diseases in modern societies. This study investigated the effect of high-fat diet on glucose-related metabolic responses to chronic foot-shock stress. Male rats were divided into high-fat diet (containing 54.21% saturated and 44.89% unsaturated fatty acids) and normal diet groups and then into stress and non-stress subgroups. The diets were applied for 5 weeks, and stress was induced during the last week of the diet course. Plasma levels of metabolic parameters, HOMA-IR index, intra-abdominal fat weight, and islets' insulin secretion were assessed. High-fat diet increased abdominal fat weight and plasma leptin, and insulin levels in response to stress without affecting HOMA-IR index and islets' insulin secretion. High proportion of unsaturated fat may not lead to deleterious metabolic responses; however combined with chronic stress has a synergistic and adverse effect on visceral adiposity and results in elevated plasma leptin.

Alternate methods for FAAT S-curve generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaufman, A.M.

The FAAT (Foreign Asset Assessment Team) assessment methodology attempts to derive a probability of effect as a function of incident field strength. The probability of effect is the likelihood that the stress put on a system exceeds its strength. In the FAAT methodology, both the stress and strength are random variables whose statistical properties are estimated by experts. Each random variable has two components of uncertainty: systematic and random. The systematic uncertainty drives the confidence bounds in the FAAT assessment. Its variance can be reduced by improved information. The variance of the random uncertainty is not reducible. The FAAT methodologymore » uses an assessment code called ARES to generate probability of effect curves (S-curves) at various confidence levels. ARES assumes log normal distributions for all random variables. The S-curves themselves are log normal cumulants associated with the random portion of the uncertainty. The placement of the S-curves depends on confidence bounds. The systematic uncertainty in both stress and strength is usually described by a mode and an upper and lower variance. Such a description is not consistent with the log normal assumption of ARES and an unsatisfactory work around solution is used to obtain the required placement of the S-curves at each confidence level. We have looked into this situation and have found that significant errors are introduced by this work around. These errors are at least several dB-W/cm{sup 2} at all confidence levels, but they are especially bad in the estimate of the median. In this paper, we suggest two alternate solutions for the placement of S-curves. To compare these calculational methods, we have tabulated the common combinations of upper and lower variances and generated the relevant S-curves offsets from the mode difference of stress and strength.« less

Short-term impact of a stress management and health promotion program on perceived stress, parental stress, health locus of control, and cortisol levels in parents of children and adolescents with diabetes type 1: a pilot randomized controlled trial.

PubMed

Tsiouli, Eleni; Pavlopoulos, Vassilis; Alexopoulos, Evangelos C; Chrousos, George; Darviri, Christina

2014-01-01

Parents of children and adolescents with diabetes type 1 (DT1) usually experience high stress levels, as they have to cope with multiple demands in their everyday life. Different complex interventions have been implemented, which sometimes have led to opposite results. The purpose of this study was to assess stress levels in parents of children and adolescents with DT1 and to evaluate the effectiveness of a stress management program (progressive muscle relaxation combined with diaphragmatic breathing) in reducing perceived and parenting stress, increasing internal locus of control, promoting healthy lifestyle, and normalizing cortisol levels. Randomized controlled trial. A total of 44 parents were randomly assigned to the intervention group (performing relaxation for eight weeks, n = 19) and control group (n = 25). Pre-post measurements included cortisol levels, lifestyle characteristics, perceived stress, perception of health, and parenting stress. A statistically significant decrease in perceived stress (from 27.21 to 19.00, P = .001), as well as in parenting stress (from 85.79 to 73.68, P = .003), was observed in the intervention group. A statistically significant difference was found in perceived stress between the two groups after the intervention (Dmean = 6.64, P = .010). No significant difference was revealed between or within the groups in cortisol levels. Significant improvement was reported by the subjects of the intervention group in various lifestyle parameters. Relaxation techniques seem to have a positive impact on stress and on various lifestyle factors in parents of children and adolescents with DT1. Future research on long-term benefits of an intervention program comprising of various relaxation schemes is warranted. Copyright © 2014 Elsevier Inc. All rights reserved.

YB-1 Is Important for Late-Stage Embryonic Development, Optimal Cellular Stress Responses, and the Prevention of Premature Senescence

PubMed Central

Lu, Zhi Hong; Books, Jason T.; Ley, Timothy J.

2005-01-01

Proteins containing “cold shock” domains belong to the most evolutionarily conserved family of nucleic acid-binding proteins known among bacteria, plants, and animals. One of these proteins, YB-1, is widely expressed throughout development and has been implicated as a cell survival factor that regulates the transcription and/or translation of many cellular growth and death-related genes. For these reasons, YB-1 deficiency has been predicted to be incompatible with cell survival. However, the majority of YB-1−/− embryos develop normally up to embryonic day 13.5 (E13.5). After E13.5, YB-1−/− embryos exhibit severe growth retardation and progressive mortality, revealing a nonredundant role of YB-1 in late embryonic development. Fibroblasts derived from YB-1−/− embryos displayed a normal rate of protein synthesis and minimal alterations in the transcriptome and proteome but demonstrated reduced abilities to respond to oxidative, genotoxic, and oncogene-induced stresses. YB-1−/− cells under oxidative stress expressed high levels of the G1-specific CDK inhibitors p16Ink4a and p21Cip1 and senesced prematurely; this defect was corrected by knocking down CDK inhibitor levels with specific small interfering RNAs. These data suggest that YB-1 normally represses the transcription of CDK inhibitors, making it an important component of the cellular stress response signaling pathway. PMID:15899865

Ameliorative Effects of Allium sativum Extract on iNOS Gene Expression and NO Production in Liver of Streptozotocin + Nicotinamide-Induced Diabetic Rats.

PubMed

Ziamajidi, Nasrin; Behrouj, Hamid; Abbasalipourkabir, Roghayeh; Lotfi, Fatemeh

2018-04-01

Diabetes mellitus (DM) is one of the most prevalent diseases in the world, which is strongly associated with liver dysfunction. Hyperglycemia, through an oxidative stress pathway, damages various tissues. Herbal medicine is a good candidate to ameliorate hyperglycemia and oxidative stress. In this study, the effects of aqueous Allium sativum (garlic) extract (AGE) on gene expression of inducible nitric oxide synthases (iNOS) and production of nitric oxide (NO) were evaluated in the liver tissue of diabetic rats. Four groups of rats contained normal control rats, garlic control rats (AGE), Streptozotocin (STZ) + nicotinamide-induced diabetic rats (DM), and diabetic rats treated with garlic (DM + AGE). Glucose levels and liver enzymes activities were determined by colorimetric assay in the serum. Gene expression of iNOS by real-time PCR, NO levels by Griess method, oxidative stress parameters by spectrophotometric method and histopathological examination by hematoxylin and eosin staining method were evaluated in the liver tissues. Glucose levels, activities of liver enzymes, oxidative stress markers, iNOS gene expression, and NO production increased significantly in diabetic rats in comparison with control rats, whereas after oral administration of garlic, these parameters decreased significantly, close to the normal levels. Hence, the beneficial effects of garlic on the liver injury of diabetes could be included in the hypoglycaemic and antioxidant properties of garlic via a decrease in gene expression of iNOS and subsequent NO production.

A Tele-Behavioral Health Intervention to Reduce Depression, Anxiety, and Stress and Improve Diabetes Self-Management.

PubMed

Mochari-Greenberger, Heidi; Vue, Lee; Luka, Andi; Peters, Aimee; Pande, Reena L

2016-08-01

Depression is prevalent among individuals with diabetes and associated with suboptimal self-management. Little is known about the feasibility and potential impact of tele-behavioral therapy to improve depressive symptoms and self-management among diabetes patients. This was a retrospective observational study of consecutive graduates enrolled in a national 8-week diabetes behavioral telehealth program between August 1, 2014, and January 31, 2015 (N = 466; mean age 56.8 ± 5.0 years; 56% female). Participant characteristics (demographics, comorbidities) were obtained by standardized questionnaire. Depression, anxiety, and stress symptoms (DASS; validated Depression Anxiety and Stress Scale 21 survey), and glucose self-testing frequency and values (point-of-care monitor) were measured at program start and completion. Changes in DASS severity and glucose self-testing frequency were assessed by chi-square tests. Changes in DASS and blood glucose levels were evaluated by paired t-tests. At baseline, approximately one in three participants had elevated depression (32%), anxiety (33%), or stress (31%) scores. Significant reductions in average DASS, depression (-8.8), anxiety (-6.9), and stress (-9.9), scores were observed at graduation among those with elevated baseline scores (p < 0.0001); most (≥80%) improved to less severe depression, anxiety, or stress categories. Improved glucose self-testing frequency (69% vs. 60% tested ≥once per week; p = 0.0005) and significant reductions in mean morning glucose levels (-12.3 mg/dL; p = 0.0002) were observed from baseline to graduation. Participants with normal versus non-normal depression scores were more likely to have lower (

Biomechanical Assessment of Restored Mandibular Molar by Endocrown in Comparison to a Glass Fiber Post-Retained Conventional Crown: 3D Finite Element Analysis.

PubMed

Helal, Mohammed Abu; Wang, Zhigang

2017-10-25

To compare equivalent and contact stresses in a mandibular molar restored by all-ceramic crowns through two methods: ceramic endocrowns and ceramic crowns supported by fiber-reinforced composite (FRC) posts and core, by using 3D finite element analysis during normal masticatory load. Three 3D models of a mandibular first molar were made and labeled as such: intact molar with no restoration (A); ceramic endocrown-restored molar (B); ceramic crown supported by FRC posts and core restored molar (C). By using 3D FE analysis with contact components, normal masticatory load was simulated. The mvM stresses in all models were calculated. Maximal mvM stresses in the ceramic of restorations, dentin, and luting cement were contrasted among models and to values of materials' strength. Contact shear and tensile stresses in the restoration/tooth interface around restorations were also calculated. The highest mvM stress levels in the enamel and dentin for the tooth restored by ceramic endocrown were lower in the crown ceramic than in tooth restored with FRC posts and all-ceramic crowns; however, in the resin adhesive cement interface it was lower for ceramic crown supported by FRC posts than the in ceramic endocrown restoration. The maximum contact shear and tensile stress values along the restoration/tooth interface of ceramic endocrowns were lower than those with ceramic crowns supported by FRC posts. Ceramic endocrown restorations presented a lower mvM stress level in dentin than the conventional ceramic crowns supported by FRC posts and core. Ceramic endocrown restorations in molars are less susceptible to damage than those with conventional ceramic crowns retained by FRC posts. Ceramic endocrowns properly cemented in molars must not be fractured or loosen during normal masticatory load. Therefore, ceramic endocrowns are advised as practicable, minimally invasive, and esthetic restorations for root canal treated mandibular molars. © 2017 by the American College of Prosthodontists.

Gaseous hydrogen-induced cracking of Ti-5Al-2.5Sn.

NASA Technical Reports Server (NTRS)

Williams, D. P.; Nelson, H. G.

1972-01-01

Study of the kinetics of hydrogen-induced cracking in the Ti-5Al-2.5Sn titanium alloy, which has a structure of acicular alpha platelets in a beta matrix. The crack-growth rate at low stress-intensity levels was found to be exponentially dependent on stress intensity but essentially independent of temperature. The crack-growth rate at intermediate stress-intensity levels was found to be independent of stress intensity but dependent on temperature in such a way that crack-growth rate was controlled by a thermally activated mechanism having an activation energy of 5500 cal/mole and varied as the square root of the hydrogen pressure. The crack-growth rate at stress-intensity levels very near the fracture toughness is presumed to be independent of environment. The results are interpreted to suggest that crack growth at high stress intensities is controlled by normal, bulk failure mechanisms such as void coalescence and the like. At intermediate stress-intensity levels the transport of hydrogen to some interaction site along the alpha-beta boundary is the rate-controlling mechanism. The crack-growth behavior at low stress intensities suggests that the hydrogen interacts at this site to produce a strain-induced hydride which, in turn, induces crack growth by restricting plastic flow at the crack tip.

Myricetin Attenuates Depressant-Like Behavior in Mice Subjected to Repeated Restraint Stress

PubMed Central

Ma, Zegang; Wang, Guilin; Cui, Lin; Wang, Qimin

2015-01-01

Increasing evidence has shown that oxidative stress may be implicated in chronic stress-induced depression. Several flavonoids with anti-oxidative effects have been proved to be anti-depressive. Myricetin is a well-defined flavonoid with the anti-oxidative, anti-inflammatory, anti-apoptotic, and neuroprotective properties. The aim of the present study is to investigate the possible effects of chronic administration of myricetin on depressant-like behaviors in mice subjected to repeated restraint (4 h/day) for 21 days. Our results showed that myricetin administration specifically reduced the immobility time in mice exposed to chronic stress, as tested in both forced swimming test and tail suspension test. Myricetin treatment improved activities of glutathione peroxidase (GSH-PX) in the hippocampus of stressed mice. In addition, myricetin treatment decreased plasma corticosterone levels of those mice subjected to repeated restraint stress. The effects of myricetin on the brain-derived neurotrophic factor (BDNF) levels in hippocampus were also investigated. The results revealed that myricetin normalized the decreased BDNF levels in mice subjected to repeated restraint stress. These findings provided more evidence that chronic administration of myricetin improves helpless behaviors. The protective effects of myricetin might be partially mediated by an influence on BDNF levels and might be attributed to myricetin-mediated anti-oxidative stress in the hippocampus. PMID:26633366

Selection of reference genes for microRNA analysis associated to early stress response to handling and confinement in Salmo salar.

PubMed

Zavala, Eduardo; Reyes, Daniela; Deerenberg, Robert; Vidal, Rodrigo

2017-05-11

MicroRNAs are key non-coding RNA molecules that play a relevant role in the regulation of gene expression through translational repression and/or transcript cleavage during normal development and physiological adaptation processes like stress. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) has become the approach normally used to determine the levels of microRNAs. However, this approach needs the use of endogenous reference. An improper selection of endogenous references can result in confusing interpretation of data. The aim of this study was to identify and validate appropriate endogenous reference miRNA genes for normalizing RT-qPCR survey of miRNAs expression in four different tissues of Atlantic salmon, under handling and confinement stress conditions associated to early or primary stress response. Nine candidate reference normalizers, including microRNAs and nuclear genes, normally used in vertebrate microRNA expression studies were selected from literature, validated by RT-qPCR and analyzed by the algorithms geNorm and NormFinder. The results revealed that the ssa-miR-99-5p gene was the most stable overall and that ssa-miR-99-5p and ssa-miR-23a-5p genes were the best combination. Moreover, the suitability of ssa-miR-99-5p and ssa-miR-23a-5p as endogeneuos reference genes was demostrated by the expression analysis of ssa-miR-193-5p gene.

The effect of ubiquinone and combined antioxidant therapy on oxidative stress markers in non-proliferative diabetic retinopathy: A phase IIa, randomized, double-blind, and placebo-controlled study.

PubMed

Rodríguez-Carrizalez, Adolfo Daniel; Castellanos-González, José Alberto; Martínez-Romero, Esaú César; Miller-Arrevillaga, Guillermo; Pacheco-Moisés, Fermín Paul; Román-Pintos, Luis Miguel; Miranda-Díaz, Alejandra Guillermina

2016-07-01

Objective To evaluate the effect of ubiquinone (Coenzyme Q10) and combined antioxidant therapy (CAT) on oxidative stress markers in non-proliferative diabetic retinopathy (NPDR) under clinical management. Study design In a randomized, double-blind, phase IIa, placebo-controlled, clinical trial, three study groups were formed and administered medications as follows: Group 1, Coenzyme Q10; Group 2, CAT; and Group 3, placebo. Methods Serum levels of the products of lipid peroxidation (LPO) and nitrites/nitrates, as markers of oxidative/nitrosative stress, were measured. As antioxidants, the total antioxidant capacity (TAC), catalase activity, and glutathione peroxidase (GPx) activity were measured. Results Baseline serum levels of LPO and nitrites/nitrates were significantly elevated in the three groups vs. healthy group (P < 0.0001), while final levels in the Coenzyme Q10 and CAT groups were decreased vs. normal levels (P < 0.0001). The baseline TAC was consumed in the three groups (P < 0.0001), while final results in the Coenzyme Q10 and CAT groups improved (P < 0.0001). Baseline catalase activity was increased in all groups vs. normal values (P < 0.001), while final levels in the Coenzyme Q10 (P < 0.001) and CAT groups (P < 0.0001) were decreased. GPx behaved similarly to catalase and improved in the final results (P < 0.0001). Discussion Adjunctive antioxidant treatment for 6 months was effective and safe for improving the oxidative stress in NPDR.

The cellular immunity and oxidative stress markers in early pregnancy loss.

PubMed

Daglar, Korkut; Biberoglu, Ebru; Kirbas, Ayse; Dirican, Aylin Onder; Genc, Metin; Avci, Aslihan; Biberoglu, Kutay

2016-01-01

We investigated whether changes in cellular immunity and oxidative stress in pregnancy have any association with spontaneous miscarriage. Circulating adenosine deaminase (ADA) activity as a marker of cellular immunity and malondialdehyde (MDA) and catalase (CAT), glutathione peroxidase (GPx) as markers of T lymphocyte activation and parameters of oxidative stress and antioxidant defense were compared between 40 women with early pregnancy loss and another 40 women with ungoing healthy pregnancy. Women with miscarriage had higher serum ADA and GPx levels when compared with women with normal pregnancy (p = 0.034 and p < 0.001, respectively). Although serum MDA level was slightly higher in women with miscarriage, the difference was not significant (p = 0.083). CAT levels were alike in both groups. We have demonstrated an increased cellular immunity and perhaps a compensated oxidative stress related to increased antioxidant activation in women with early spontaneous pregnancy loss.

Toward an understanding of mechanism of aging-induced oxidative stress in human mesenchymal stem cells.

PubMed

Benameur, Laila; Charif, Naceur; Li, Yueying; Stoltz, Jean-François; de Isla, Natalia

2015-01-01

Under physiological conditions, there is a production of limited range of free radicals. However, when the cellular antioxidant defence systems, overwhelm and fail to reverse back the free radicals to their normal basal levels, there is a creation of a condition of redox disequilibrium termed "oxidative stress", which is implicated in a very wide spectrum of genetic, metabolic, and cellular responses. The excess of free radicals can, cause unfavourable molecular alterations to biomolecules through oxidation of lipids, proteins, RNA and DNA, that can in turn lead to mutagenesis, carcinogenesis, and aging. Mesenchymal stem cells (MSCs) have been proven to be a promising source of cells for regenerative medicine, and to be useful in the treatment of pathologies in which tissue damage is linked to oxidative stress. Moreover, MSCs appeared to efficiently manage oxidative stress and to be more resistant to oxidative insult than normal somatic cells, making them an interesting and testable model for the role of oxidative stress in the aging process. In addition, aging is accompanied by a progressive decline in stem cell function, resulting in less effective tissue homeostasis and repair. Also, there is an obvious link between intracellular reactive oxygen species levels and cellular senescence. To date, few studies have investigated the promotion of aging by oxidative stress on human MSCs, and the mechanism by which oxidative stress induce stem cell aging is poorly understood. In this context, the aim of this review is to gain insight the current knowledge about the molecular mechanisms of aging-induced oxidative stress in human MSCs.

Adrenal cortical response to stress at Three Mile Island.

PubMed

Schaeffer, M A; Baum, A

1984-01-01

The present study examined the relationship between biochemical, psychologic, and behavioral components of chronic stress associated with living near the damaged nuclear power plant at Three Mile Island (TMI). Relative to control subjects, TMI subjects had higher levels of urinary cortisol, which correlated significantly with urinary catecholamines, self-report of physical and mental symptoms, and decrements in task performance. Further, it was found that males had higher urinary cortisol levels than females at TMI, while at the control sites, levels of cortisol were comparable between males and females. Finally, no significant relationship between coping style and urinary cortisol was detected. Levels of stress response among TMI are residents, though significantly greater than control subjects, were within normal ranges and thus should be considered subclinical in intensity. Their persistence over 17 months, however, suggests some cause for concern.

Repressed SIRT1/PGC-1α pathway and mitochondrial disintegration in iPSC-derived RPE disease model of age-related macular degeneration.

PubMed

Golestaneh, Nady; Chu, Yi; Cheng, Shuk Kei; Cao, Hong; Poliakov, Eugenia; Berinstein, Daniel M

2016-12-20

Study of age related macular degeneration (AMD) has been hampered by lack of human models that represent the complexity of the disease. Here we have developed a human in vitro disease model of AMD to investigate the underlying AMD disease mechanisms. Generation of iPSCs from retinal pigment epithelium (RPE) of AMD donors, age-matched normal donors, skin fibroblasts of a dry AMD patient, and differentiation of iPSCs into RPE (AMD RPE-iPSC-RPE, normal RPE-iPSC-RPE and AMD Skin-iPSC-RPE, respectively). Immunostaining, cell viability assay and reactive oxygen species (ROS) production under oxidative stress conditions, electron microscopy (EM) imaging, ATP production and glycogen concentration assays, quantitative real time PCR, western blot, karyotyping. The AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE present functional impairment and exhibit distinct disease phenotypes compared to RPE-iPSC-RPE generated from normal donors (Normal RPE-iPSC-RPE). The AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE show increased susceptibility to oxidative stress and produced higher levels of reactive oxygen species (ROS) under stress in accordance with recent reports. The susceptibility to oxidative stress-induced cell death in AMD RPE-iPSC-RPE and Skin-iPSC-RPE was consistent with inability of the AMD RPE-iPSC-RPE and Skin-iPSC-RPE to increase SOD2 expression under oxidative stress. Phenotypic analysis revealed disintegrated mitochondria, accumulation of autophagosomes and lipid droplets in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE. Mitochondrial activity was significantly lower in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE compared to normal cells and glycogen concentration was significantly increased in the diseased cells. Furthermore, Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a regulator of mitochondrial biogenesis and function was repressed, and lower expression levels of NAD-dependent deacetylase sirtuin1 (SIRT1) were found in AMD RPE-iPSC-RPE and AMD Skin-iPSC-RPE as compared to normal RPE-iPSC-RPE. Our studies suggest SIRT1/PGC-1α as underlying pathways contributing to AMD pathophysiology, and open new avenues for development of targeted drugs for treatment of this devastating neurodegenerative disease of the visual system.

Early Life Stress Differentially Modulates Distinct Forms of Brain Plasticity in Young and Adult Mice

PubMed Central

Reichardt, Wilfried; Clark, Kristin; Geiger, Julia; Gross, Claus M.; Heyer, Andrea; Neagu, Valentin; Bhatia, Harsharan; Atas, Hasan C.; Fiebich, Bernd L.; Bischofberger, Josef; Haas, Carola A.; Normann, Claus

2012-01-01

Background Early life trauma is an important risk factor for many psychiatric and somatic disorders in adulthood. As a growing body of evidence suggests that brain plasticity is disturbed in affective disorders, we examined the short-term and remote effects of early life stress on different forms of brain plasticity. Methodology/Principal Findings Mice were subjected to early deprivation by individually separating pups from their dam in the first two weeks after birth. Distinct forms of brain plasticity were assessed in the hippocampus by longitudinal MR volumetry, immunohistochemistry of neurogenesis, and whole-cell patch-clamp measurements of synaptic plasticity. Depression-related behavior was assessed by the forced swimming test in adult animals. Neuropeptides and their receptors were determined by real-time PCR and immunoassay. Early maternal deprivation caused a loss of hippocampal volume, which returned to normal in adulthood. Adult neurogenesis was unaffected by early life stress. Long-term synaptic potentiation, however, was normal immediately after the end of the stress protocol but was impaired in adult animals. In the forced swimming test, adult animals that had been subjected to early life stress showed increased immobility time. Levels of substance P were increased both in young and adult animals after early deprivation. Conclusion Hippocampal volume was affected by early life stress but recovered in adulthood which corresponded to normal adult neurogenesis. Synaptic plasticity, however, exhibited a delayed impairment. The modulation of synaptic plasticity by early life stress might contribute to affective dysfunction in adulthood. PMID:23071534

Low-level infrared laser modulates muscle repair and chromosome stabilization genes in myoblasts.

PubMed

da Silva Neto Trajano, Larissa Alexsandra; Stumbo, Ana Carolina; da Silva, Camila Luna; Mencalha, Andre Luiz; Fonseca, Adenilson S

2016-08-01

Infrared laser therapy is used for skeletal muscle repair based on its biostimulative effect on satellite cells. However, shortening of telomere length limits regenerative potential in satellite cells, which occurs after each cell division cycle. Also, laser therapy could be more effective on non-physiologic tissues. This study evaluated low-level infrared laser exposure effects on mRNA expression from muscle injury repair and telomere stabilization genes in myoblasts in normal and stressful conditions. Laser fluences were those used in clinical protocols. C2C12 myoblast cultures were exposed to low-level infrared laser (10, 35, and 70 J/cm(2)) in standard or normal (10 %) and reduced (2 %) fetal bovine serum concentrations; total RNA was extracted for mRNA expression evaluation from muscle injury repair (MyoD and Pax7) and chromosome stabilization (TRF1 and TRF2) genes by real time quantitative polymerization chain reaction. Data show that low-level infrared laser increases the expression of MyoD and Pax7 in 10 J/cm(2) fluence, TRF1 expression in all fluences, and TRF2 expression in 70 J/cm(2) fluence in both 10 and 2 % fetal bovine serum. Low-level infrared laser increases mRNA expression from genes related to muscle repair and telomere stabilization in myoblasts in standard or normal and stressful conditions.

BDNF in sleep, insomnia, and sleep deprivation.

PubMed

Schmitt, Karen; Holsboer-Trachsler, Edith; Eckert, Anne

2016-01-01

The protein brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors involved in plasticity of neurons in several brain regions. There are numerous evidence that BDNF expression is decreased by experiencing psychological stress and that, accordingly, a lack of neurotrophic support causes major depression. Furthermore, disruption in sleep homeostatic processes results in higher stress vulnerability and is often associated with stress-related mental disorders. Recently, we reported, for the first time, a relationship between BDNF and insomnia and sleep deprivation (SD). Using a biphasic stress model as explanation approach, we discuss here the hypothesis that chronic stress might induce a deregulation of the hypothalamic-pituitary-adrenal system. In the long-term it leads to sleep disturbance and depression as well as decreased BDNF levels, whereas acute stress like SD can be used as therapeutic intervention in some insomniac or depressed patients as compensatory process to normalize BDNF levels. Indeed, partial SD (PSD) induced a fast increase in BDNF serum levels within hours after PSD which is similar to effects seen after ketamine infusion, another fast-acting antidepressant intervention, while traditional antidepressants are characterized by a major delay until treatment response as well as delayed BDNF level increase. Key messages Brain-derived neurotrophic factor (BDNF) plays a key role in the pathophysiology of stress-related mood disorders. The interplay of stress and sleep impacts on BDNF level. Partial sleep deprivation (PSD) shows a fast action on BDNF level increase.

Speech perception in older listeners with normal hearing:conditions of time alteration, selective word stress, and length of sentences.

PubMed

Cho, Soojin; Yu, Jyaehyoung; Chun, Hyungi; Seo, Hyekyung; Han, Woojae

2014-04-01

Deficits of the aging auditory system negatively affect older listeners in terms of speech communication, resulting in limitations to their social lives. To improve their perceptual skills, the goal of this study was to investigate the effects of time alteration, selective word stress, and varying sentence lengths on the speech perception of older listeners. Seventeen older people with normal hearing were tested for seven conditions of different time-altered sentences (i.e., ±60%, ±40%, ±20%, 0%), two conditions of selective word stress (i.e., no-stress and stress), and three different lengths of sentences (i.e., short, medium, and long) at the most comfortable level for individuals in quiet circumstances. As time compression increased, sentence perception scores decreased statistically. Compared to a natural (or no stress) condition, the selectively stressed words significantly improved the perceptual scores of these older listeners. Long sentences yielded the worst scores under all time-altered conditions. Interestingly, there was a noticeable positive effect for the selective word stress at the 20% time compression. This pattern of results suggests that a combination of time compression and selective word stress is more effective for understanding speech in older listeners than using the time-expanded condition only.

Effects of routine handling and tagging procedures on physiological stress responses in juvenile chinook salmon

USGS Publications Warehouse

Sharpe, C.S.; Thompson, D.A.; Blankenship, H.L.; Schreck, C.B.

1998-01-01

Juvenile chinook salmon Oncorhynchus tshawytscha were subjected to handling and tagging protocols typical of normal hatchery operations and monitored for their physiological response to stress. Treatments included coded-wire-tagging, counting, ventral fin clipping, adipose fin clipping, and a procedure simulating a pond split. Treatment fish were also subjected to a standardized stress challenge (1 h confinement) to evaluate their ability to deal with disturbances subsequent to a handling or tagging procedure. Circulating levels of cortisol and glucose were used as indicators of stress. Each of the treatments elicited very similar responses among treatment groups. Cortisol increased from resting levels of about 20 ng/mL to about 90 ng/mL by 1 h poststress and returned to near resting levels by 8 h poststress. Glucose levels increased from 50 mg/dL to about 80 mg/dL by 1 h poststress and remained elevated for much of the experiment. The cortisol and glucose responses to the confinement stress did not differ over time or among treatments. However, the confinement stress results do suggest a small but significant cumulative response, indicating small residual effects of the original handling protocols. No deaths were noted among treatment groups.

Differential Expression Analysis of a Subset of Drought-Responsive GmNAC Genes in Two Soybean Cultivars Differing in Drought Tolerance

PubMed Central

Thao, Nguyen Phuong; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Van Ha, Chien; Tran, Lam-Son Phan

2013-01-01

The plant-specific NAC transcription factors play important roles in plant response to drought stress. Here, we have compared the expression levels of a subset of GmNAC genes in drought-tolerant DT51 and drought-sensitive MTD720 under both normal and drought stress conditions aimed at identifying correlation between GmNAC expression levels and drought tolerance degree, as well as potential GmNAC candidates for genetic engineering. The expression of 23 selected dehydration-responsive GmNACs was assessed in both stressed and unstressed root tissues of DT51 and MTD720 using real-time quantitative PCR. The results indicated that expression of GmNACs was genotype-dependent. Seven and 13 of 23 tested GmNACs showed higher expression levels in roots of DT51 in comparison with MTD720 under normal and drought stress conditions, respectively, whereas none of them displayed lower transcript levels under any conditions. This finding suggests that the higher drought tolerance of DT51 might be positively correlated with the higher induction of the GmNAC genes during water deficit. The drought-inducible GmNAC011 needs to be mentioned as its transcript accumulation was more than 76-fold higher in drought-stressed DT51 roots relative to MTD720 roots. Additionally, among the GmNAC genes examined, GmNAC085, 092, 095, 101 and 109 were not only drought-inducible but also more highly up-regulated in DT51 roots than in that of MTD720 under both treatment conditions. These data together suggest that GmNAC011, 085, 092, 095, 101 and 109 might be promising candidates for improvement of drought tolerance in soybean by biotechnological approaches. PMID:24322442

Protective effects of azelaic acid against high-fat diet-induced oxidative stress in liver, kidney and heart of C57BL/6J mice.

PubMed

Muthulakshmi, Shanmugam; Saravanan, Ramalingam

2013-05-01

Excess fat intake induces hyperinsulinaemia, increases nutrient uptake and lipid accumulation, amplifies ROS generation, establishes oxidative stress and morphological changes leading to tissue injury in the liver, kidney and heart of high-fat diet (HFD)-fed mice. The effect of azelaic acid (AzA), a C9 α,ω-dicarboxylic acid, against HFD-induced oxidative stress was investigated by assaying the activities and levels of antioxidants and oxidative stress markers in the liver, kidney and heart of C57BL/6J mice. Mice were segregated into two groups, one fed standard diet (NC) and the other fed high-fat diet (HFD) for 15 weeks. HFD-fed mice were subjected to intragastric administration of AzA (80 mg/kg BW)/RSG (10 mg/kg BW) during 11-15 weeks. Glucose, insulin, triglycerides, hepatic and nephritic markers were analysed in the plasma and the activity of enzymatic, non-enzymatic antioxidants and lipid peroxidation markers were examined in the plasma/erythrocytes, liver, kidney and heart of normal and experimental mice. We inferred significant decrease in enzymatic and non-enzymatic antioxidants along with significant increase in glucose, insulin, hepatic and nephritic markers, triglycerides and lipid peroxidation markers in HFD-fed mice. Administration of AzA could positively restore the levels of plasma glucose, insulin, triglycerides, hepatic and nephritic markers to near normal. AzA increased the levels of enzymatic and nonenzymatic antioxidants with significant reduction in the levels of lipid peroxidation markers. Histopathological examination of liver, kidney and heart substantiated these results. Hence, we put forward that AzA could counteract the potential injurious effects of HFD-induced oxidative stress in C57BL/6J mice.

The Characteristic Long-Term Upregulation of Hippocampal NF-κB Complex in PTSD-Like Behavioral Stress Response Is Normalized by High-Dose Corticosterone and Pyrrolidine Dithiocarbamate Administered Immediately after Exposure

PubMed Central

Cohen, Hagit; Kozlovsky, Nitsan; Matar, Michael A; Zohar, Joseph; Kaplan, Zeev

2011-01-01

Nuclear factor-κB (NF-κB) is a ubiquitously expressed transcription factor for genes involved in cell survival, differentiation, inflammation, and growth. This study examined the role of NF-κB pathway in stress-induced PTSD-like behavioral response patterns in rats. Immunohistochemical technique was used to detect the expression of the NF-κB p50 and p65 subunits, I-κBα, p38, and phospho-p38 in the hippocampal subregions at 7 days after exposure to predator scent stress. Expression of p65 nuclear translocation was quantified by western blot as the level of NF-κB activation. The effects of intraperitoneally administered corticosterone or a selective NF-κB inhibitor (pyrrolidine dithiocarbamate (PDTC)) at 1 h post exposure on behavioral tests (elevated plus-maze and acoustic startle response) were evaluated 7 days later. Hippocampal expressions of those genes were subsequently evaluated. All data were analyzed in relation to individual behavior patterns. Extreme behavioral responder animals displayed significant upregulation of p50 and p65 with concomitant downregulation of I-κBα, p38, and phospho-p38 levels in hippocampal structures compared with minimal behavioral responders and controls. Immediate post-exposure treatment with high-dose corticosterone and PDTC significantly reduced prevalence rates of extreme responders and normalized the expression of those genes. Stress-induced upregulation of NF-κB complex in the hippocampus may contribute to the imbalance between what are normally precisely orchestrated and highly coordinated physiological and behavioral processes, thus associating it with stress-related disorders. PMID:21734649

Constraints on Friction, Dilatancy, Diffusivity, and Effective Stress From Low-Frequency Earthquake Rates on the Deep San Andreas Fault

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David

2018-01-01

Families of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor on the San Andreas Fault in central California are sensitive to tidal stresses. LFEs occur at all levels of the tides, are strongly correlated and in phase with the 200 Pa shear stresses, and weakly and not systematically correlated with the 2 kPa tidal normal stresses. We assume that LFEs are small sources that repeatedly fail during shear within a much larger scale, aseismically slipping fault zone and consider two different models of the fault slip: (1) modulation of the fault slip rate by the tidal stresses or (2) episodic slip, triggered by the tides. LFEs are strongly clustered with duration much shorter than the semidiurnal tide; they cannot be significantly modulated on that time scale. The recurrence times of clusters, however, are many times longer than the semidiurnal, leading to an appearance of tidal triggering. In this context we examine the predictions of laboratory-observed triggered frictional (dilatant) fault slip. The undrained end-member model produces no sensitivity to the tidal normal stress, and slip onsets are in phase with the tidal shear stress. The tidal correlation constrains the diffusivity to be less than 1 × 10-6/s and the product of the friction and dilatancy coefficients to be at most 5 × 10-7, orders of magnitude smaller than observed at room temperature. In the absence of dilatancy the effective normal stress at failure would be about 55 kPa. For this model the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid.

Differential Effects of Inescapable Stress on Locus Coeruleus GRK3, Alpha2-Adrenoceptor and CRF1 Receptor Levels in Learned Helpless and Non-Helpless Rats: A potential link to stress resilience

PubMed Central

Taneja, Manish; Salim, Samina; Saha, Kaustuv; Happe, H. Kevin; Qutna, Nidal; Petty, Frederick; Bylund, David B.; Eikenburg, Douglas C.

2011-01-01

Exposure of rats to unpredictable, inescapable stress results in two distinct behaviors during subsequent escape testing. One behavior, suggestive of lack of stress resilience, is prolonged escape latency compared to non-stressed rats and is labeled learned helplessness (LH). The other behavior suggestive of stress resilience is normal escape latency and is labeled non-helpless (NH). This study examines the effects of unpredictable, inescapable tail-shock stress (TSS) on alpha2-adrenoceptor (α2-AR) and corticotropin-releasing factor 1 receptor (CRF1) regulation as well as protein levels of G protein-coupled receptor kinase 3 (GRK3), GRK2, tyrosine hydroxylase (TH) plus carbonylated protein levels in locus coeruleus (LC), amygdala (AMG), cortex (COR) and striatum (STR). In NH rats, α2-AR and CRF1 receptors were significantly down-regulated in LC after TSS. No changes in these receptor levels were observed in the LC of LH rats. GRK3, which phosphorylates receptors and thereby contributes to α2-AR and CRF1 receptor down-regulation, was reduced in the LC of LH but not NH rats. GRK2 levels were unchanged. In AMG, GRK3 but not GRK2 levels were reduced in LH but not NH rats, and receptor regulation was impaired in LH rats. In STR, no changes in GRK3 or GRK2 levels were observed. Finally, protein carbonylation, an index of oxidative stress, was increased in the LC and AMG of LH but not NH rats. We suggest that reduced stress resilience after TSS may be related to oxidative stress, depletion of GRK3 and impaired regulation of α2-AR and CRF1 receptor in LC. PMID:21333691

Residual stresses in welded plates

NASA Technical Reports Server (NTRS)

Bernstein, Edward L.

1994-01-01

The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

The role of the habenula-interpeduncular pathway in modulating levels of circulating adrenal hormones.

PubMed

Murray, M; Murphy, C A; Ross, L L; Haun, F

1994-01-01

The fasciculus retroflexus (FR) is the major pathway by which the medial and lateral habenular nuclei project to the interpeduncular nucleus (IPN) and ventral tegmentum. Recent work has suggested that the habenula-interpeduncular system may be involved in the regulation of states of arousal. Bilateral FR lesions have been shown to disrupt chronically, and habenula transplants have been shown to restore normal sleep patterns in rats [J. NeuroscL, 12 (1992) 3282-3290]. In this study, we examined whether FR lesions and habenula cell transplants would also modify chronically the circulating plasma levels of the stress-related hormones, norepinephrine (NE), epinephrine (EPI) and corticosterone. When plasma samples were obtained via retro-orbital eye-bleed during anesthesia, animals with FR lesions had significantly increased levels of plasma NE, EPI and corticosterone 2-3 months postoperatively compared to unoperated controls. Transplants of embryonic habenula cells placed near the denervated IPN in FR-lesioned animals restored levels of NE and EPI to normal, but did not attenuate elevated corticosterone levels. When plasma samples were obtained in conscious animals via indwelling arterial cannulae, FR-lesioned rats likewise exhibited increased basal levels of corticosterone but plasma levels of catecholamines were similar to those of unoperated controls. Differences in our results obtained using the two methods of blood sampling may be explained by the effects of anesthesia and stress associated with the eye-bleed method. Thus, the effect of FR lesions in increasing plasma levels of catecholamines may not reflect a difference in basal hormone levels, but a heightened sympathetic adrenomedullary response to stress. While these results indicate that the integrity of the habenular efferent pathway is important in modulating circulating levels of hormones associated with the stress response, two separate mechanisms appear to control its interactions with sympathetic-adrenal medullary and adrenocortical pathways.

Oxidative Stress Correlates with Headache Symptoms in Fibromyalgia: Coenzyme Q10 Effect on Clinical Improvement

PubMed Central

Cordero, Mario D.; Cano-García, Francisco Javier; Alcocer-Gómez, Elísabet; De Miguel, Manuel; Sánchez-Alcázar, José Antonio

2012-01-01

Background Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q10 (CoQ10) supplementation on biochemical markers and clinical improvement were also evaluated. Methods We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ10, catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. Results We found decreased CoQ10, catalase and ATP levels in BMCs from FM patients as compared to normal control (P<0.05 and P<0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P<0.001). Significant negative correlations between CoQ10 or catalase levels in BMCs and headache parameters were observed (r = −0.59, P<0.05; r = −0.68, P<0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ10 supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P<0.001). Discussion The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM. PMID:22532869

Oxidative stress correlates with headache symptoms in fibromyalgia: coenzyme Q₁₀ effect on clinical improvement.

PubMed

Cordero, Mario D; Cano-García, Francisco Javier; Alcocer-Gómez, Elísabet; De Miguel, Manuel; Sánchez-Alcázar, José Antonio

2012-01-01

Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q(10) (CoQ(10)) supplementation on biochemical markers and clinical improvement were also evaluated. We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ(10), catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. We found decreased CoQ(10), catalase and ATP levels in BMCs from FM patients as compared to normal control (P < 0.05 and P < 0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P < 0.001). Significant negative correlations between CoQ(10) or catalase levels in BMCs and headache parameters were observed (r  = -0.59, P < 0.05; r  =  -0.68, P < 0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ(10) supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P < 0.001). The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM.

[Analysis of the binding capacity of the benzodiazepine site of gabaa receptor in mice C57BL/6 and BALB/C pretreated with anxiolytics].

PubMed

Iarkova, M A

2011-01-01

The level of specific 3H-flunitrazepam binding in synaptosomal membranes of C57BL/6 and BALB/c mice brain underwent to the stress of different types has been studied. Mild stress (Elevated Plus Maze) was shown to induce the decrease of benzodiazepine binding in BALB/c mice only, while the strong one (Exposure to a predator) was revealed to cause this decrease in both strains. Behavioral effects of different non-benzodiazepine drugs possessing anxiolytic properties (Afobazol, Ladasten and Noopept) was accompanied with the normalization of the level of benzodiazepine reception, reduced by the stress of both modalities.

[Effect of stress on nucleic acid metabolism in the rat spleen and liver after a flight on the Kosmos-1129 biosatellite].

PubMed

Komolova, G S; Troitskaia, E N; Egorov, I A; Tigranian, R A

1982-01-01

Changes in nucleic acid metabolism of the spleen and liver of rats flown for 18.5 days on Cosmos-112 were investigated. Postflight changes in the liver RNA synthesis after an additional stress effect (immobilization) in the flown rats were expressed to a lesser degree than in the controls. The DNA synthesis remained essentially at the preflight level. The tissue content of nucleic acids suggests that postflight the dystrophic changes induced by the additional stress effect increased. It is very likely that an exposure to space flight effects contributes to the depletion of compensatory mechanisms maintaining the normal level of metabolic processes.

Low Cobalamin Levels as Predictors of Cobalamin Deficiency: Importance of Comorbidities Associated with Increased Oxidative Stress.

PubMed

Solomon, Lawrence R

2016-01-01

Cobalamin (B12) deficiency can lead to irreversible neurocognitive changes if unrecognized. Screening involves measurement of serum cobalamin levels, but the sensitive metabolic indicators of cobalamin deficiency, methylmalonic acid (MMA) and homocysteine (HCys), may be normal when cobalamin values are low and elevated when cobalamin values are normal. Because cobalamin is inactivated by oxidation, the relationship between these metabolites and comorbidities associated with increased oxidative stress (oxidant risks) in subjects with low and low-normal cobalamin levels was studied. A retrospective record-review was conducted of community-dwelling adults evaluated for cobalamin deficiency during a 12-year period with serum cobalamin values in the low (≤ 200 pg/mL; n = 49) or low-normal (201-300 pg/mL; n = 187) range and concurrent measurement of MMA. When "No" oxidant risk was present, elevated MMA (>250 nmol/L) and HCys (>12.1 μmol/L) values occurred in 50% and 30% of subjects, respectively (P <.01). In contrast, when "Three or More" oxidant risks were present, mean MMA and HCys values were significantly higher, and elevated MMA and HCys values occurred in 84% and 78% of these subjects, respectively (P ≤.012). Pharmacologic doses of cyanocobalamin significantly decreased metabolite values in ≥ 94% of treated subjects. In subjects with low or low-normal cobalamin values, metabolic evidence of cobalamin deficiency is more frequent when 3 or more oxidant risks are present. Thus, defining a low serum cobalamin level to screen for cobalamin deficiency may be a "moving target" due to the variable presence and severity of often subtle, confounding clinical conditions in individual subjects. Copyright © 2016 Elsevier Inc. All rights reserved.

Combating photooxidative stress in green hairy roots of Daucus carota cultivated under light irradiation.

PubMed

Mukherjee, Chiranjit; Sircar, Debabrata; Chatterjee, Moniya; Das, Sampa; Mitra, Adinpunya

2014-01-15

The light-dependent generation of active oxygen species, which can disrupt normal metabolic process of plant, is termed as photo-oxidative stress. Plants are equipped with enzymatic and non-enzymatic antioxidative defence system to reduce the effect of such stress. Hairy root culture of Daucus carota when cultivated under continuous illumination (250 μmol m(-2)s(-1)) turned green. To know the reason behind that and photo-oxidative stress response in green hairy roots, activities of several antioxidant enzymes were measured. When compared with normal hairy roots, green hairy roots showed an enhanced superoxide dismutase (SOD) activity. Treatment with a SOD inhibitor diethyldithiocarbamate led to suppression of SOD activity in a concentration-dependent manner in green hairy roots. Interestingly, SOD-suppressed root showed three-fold enhanced caffeic acid glucoside accumulation in the soluble fraction as compared to untreated ones. While ascorbate peroxidase activity showed marginal increase in green hairy roots, a decrease in the activities of guaiacol peroxidase and catalase were observed. SDS-PAGE of crude protein profile from green hairy roots showed a distinct band, which was absent in normal hairy roots. MALDI-TOF-MS/MS analysis of the extracted protein confirmed it as the large subunit of RuBisCO. RT-PCR based expression analysis of betaine aldehyde dehydrogenase showed enhanced transcript levels in green hairy roots as compared to normal hairy roots, whereas reverse trends were observed with the transcripts accumulation for phenylalanine ammonia-lyase and chalcone synthase. These findings corroborate with the in vitro BADH activities in hairy roots, and thus indicate an important role of this stress enzyme in combating photo-oxidative stress in green hairy roots upon continuous light exposure. Copyright © 2013 Elsevier GmbH. All rights reserved.

Role of Paraoxonase 1 Activity and Oxidative/Antioxidative Stress Markers in Patients with Acute Cerebral Infarction.

PubMed

Zhu, Hui; Zhao, Teng; Liu, Jingyao

2018-06-01

Paraoxonase1 (PON1) is an antioxidant which confers antioxidant properties to high-density lipoprotein (HDL) and prevents low-density lipoprotein (LDL) oxidation. The purpose of this study was to evaluate the activities of PON1 and oxidative/antioxidative stress markers in acute cerebral infarction. In this study, 161 patients diagnosed with acute cerebral infarction and 161 gender- and age-matched healthy controls were recruited. Based on the clinicoradiological profiles, the patients were further classified into two groups: lacunar infarction group and large-artery atherosclerosis group. We measured the individual lipid status parameters, oxidative and antioxidative stress status parameters, and PON1 activity. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and oxidative stress parameters in patients with acute cerebral infarction were significantly higher than those in the normal controls (p < 0.05). High-density lipoprotein cholesterol (HDL-C) level, PON1 activity, superoxide dismutase (SOD) activity, and antioxidative stress parameters in patients were lower than in the normal controls (p < 0.05). Superoxide anion (O2-), malondialdehyde (MDA), and PON1 levels in the lacunar infarction group were lower than in the large-artery atherosclerosis group (p < 0.05). Oxidative stress markers and PON1 activity are sensitive indicators of acute cerebral infarction. Our findings suggest a severely impaired antioxidative protection mechanism in these patients. Our study provides new insights into the pathophysiological mechanisms of acute cerebral infarction, which may also provide new therapeutic targets for ischemic cerebrovascular diseases.

[Thyroid function in patients with anorexia nervosa and depression].

PubMed

Natori, Y; Yamaguchi, N; Koike, S; Aoyama, A; Tsuchibuchi, S; Kojyo, K; Demura, R

1994-12-01

Thyroid hormone levels were measured in 21 patients with anorexia nervosa, 15 patients with depression and 16 patients with severe depression and were compared with those in 53 normal subjects. In anorexia nervosa and severe depressed patients, serum T3, T4, fT3, fT4 and T3/T4 ratio showed significantly lower values than those in normal subjects. However there was no difference between depressed patients and normal subjects. The serum TSH levels were within normal range in all of the studied subjects. Thus, thyroid hormone levels in severe depressed patients were similar to those in anorexia nervosa and the changes were inversely related to disease conditions. The supplementation of thyroid hormones to antidepressant relieved clinical symptoms in some of the severe depressed patients. These results suggested that the changes in thyroid hormone levels in anorexia nervosa and severe depression were mainly due to impaired conversion of T4 to T3 by increased cortisol secretion through emotional stress.

Effect of second to first normal stress difference ratio at the die exit on neck-in phenomenon in polymeric flat film production

NASA Astrophysics Data System (ADS)

Barborik, Tomas; Zatloukal, Martin

2017-05-01

In this study, viscoelastic modeling of the extrusion film casting process, based on the lD membrane model and modified Leonov constitutive equation, was conducted and the effect of the viscoelastic stress state at the die exit (captured here via second to first normal stress difference ratio) on the unwanted neck-in phenomenon has been analyzed for wide range of Deborah numbers and materials having different level of uniaxial and planar extensional strain hardening. Relevant experimental data for LDPE and theoretical predictions based on multimode eXtended Pom-Pom model acquired from the open literature were used for the validation purposes. It was found that firstly, the predicting capabilities of both constitutive equations for given material and processing conditions are comparable even if the single mode modified Leonov model was used and secondly, the agreement between theoretical and experimental data on neck-in is fairly good. Results of the theoretical study revealed that the viscoelastic stress state at the die exit (i.e. -N2/N1 ratio) increases the level of neck-in if uniaxial extensional strain hardening, planar to uniaxial extensional viscosity ratio and Deborah number increases. It has also been revealed that there exists threshold value for Deborah number and extensional strain hardening below which the neck-in becomes independent on the die exit stress state.

Resource Optimization Techniques and Security Levels for Wireless Sensor Networks Based on the ARSy Framework.

PubMed

Parenreng, Jumadi Mabe; Kitagawa, Akio

2018-05-17

Wireless Sensor Networks (WSNs) with limited battery, central processing units (CPUs), and memory resources are a widely implemented technology for early warning detection systems. The main advantage of WSNs is their ability to be deployed in areas that are difficult to access by humans. In such areas, regular maintenance may be impossible; therefore, WSN devices must utilize their limited resources to operate for as long as possible, but longer operations require maintenance. One method of maintenance is to apply a resource adaptation policy when a system reaches a critical threshold. This study discusses the application of a security level adaptation model, such as an ARSy Framework, for using resources more efficiently. A single node comprising a Raspberry Pi 3 Model B and a DS18B20 temperature sensor were tested in a laboratory under normal and stressful conditions. The result shows that under normal conditions, the system operates approximately three times longer than under stressful conditions. Maintaining the stability of the resources also enables the security level of a network's data output to stay at a high or medium level.

Resource Optimization Techniques and Security Levels for Wireless Sensor Networks Based on the ARSy Framework

PubMed Central

Kitagawa, Akio

2018-01-01

Wireless Sensor Networks (WSNs) with limited battery, central processing units (CPUs), and memory resources are a widely implemented technology for early warning detection systems. The main advantage of WSNs is their ability to be deployed in areas that are difficult to access by humans. In such areas, regular maintenance may be impossible; therefore, WSN devices must utilize their limited resources to operate for as long as possible, but longer operations require maintenance. One method of maintenance is to apply a resource adaptation policy when a system reaches a critical threshold. This study discusses the application of a security level adaptation model, such as an ARSy Framework, for using resources more efficiently. A single node comprising a Raspberry Pi 3 Model B and a DS18B20 temperature sensor were tested in a laboratory under normal and stressful conditions. The result shows that under normal conditions, the system operates approximately three times longer than under stressful conditions. Maintaining the stability of the resources also enables the security level of a network’s data output to stay at a high or medium level. PMID:29772773

Refining the multisystem view of the stress response: Coordination among cortisol, alpha-amylase, and subjective stress in response to relationship conflict

PubMed Central

Powers, Sally I.; Granger, Douglas A.

2013-01-01

This study investigated associations among young adults' hypothalamic-pituitary-adrenal axis activity, autonomic nervous system activity, and subjective stress in response to interpersonal conflict to better characterize coordination across stress systems. Seven saliva samples were collected from 199 young adult opposite-sex couples before, during, and after they discussed an unresolved relationship conflict. Samples were later assayed for cortisol and alpha-amylase (sAA). Couples rated anticipatory stress prior to the conflict and perceived stress immediately following the task. Growth curve modeling was used to examine two possible levels of within-person coordination across physiological systems: alignment between cortisol and sAA responses throughout the sampling period (“matched phase coordination”), and association between overall levels of cortisol and sAA in response to conflict (“average level coordination”). Whereas both partners showed the former type of coordination, only women showed the latter type. Positive anticipation of the stressor predicted stronger cortisol-sAA matched phase coordination for women. Pre-task ratings related to women's sAA, and post-task ratings related to both partners' cortisol responses. Implications for a multisystem interpretation of normal and pathological responses to daily stress are discussed. PMID:23684904

Reduction of oxidative-nitrosative stress underlies anticataract effect of topically applied tocotrienol in streptozotocin-induced diabetic rats

PubMed Central

Abdul Nasir, Nurul Alimah; Agarwal, Renu; Sheikh Abdul Kadir, Siti Hamimah; Vasudevan, Sushil; Tripathy, Minaketan; Iezhitsa, Igor; Mohammad Daher, Aqil; Ibrahim, Mohd Ikraam; Mohd Ismail, Nafeeza

2017-01-01

Cataract, a leading cause of blindness, is of special concern in diabetics as it occurs at earlier onset. Polyol accumulation and increased oxidative-nitrosative stress in cataractogenesis are associated with NFκB activation, iNOS expression, ATP depletion, loss of ATPase functions, calpain activation and proteolysis of soluble to insoluble proteins. Tocotrienol was previously shown to reduce lens oxidative stress and inhibit cataractogenesis in galactose-fed rats. In current study, we investigated anticataract effects of topical tocotrienol and possible mechanisms involved in streptozotocin-induced diabetic rats. Diabetes was induced in Sprague Dawley rats by intraperitoneal injection of streptozotocin. Diabetic rats were treated with vehicle (DV) or tocotrienol (DT). A third group consists of normal, non-diabetic rats were treated with vehicle (NV). All treatments were given topically, bilaterally, twice daily for 8 weeks with weekly slit lamp monitoring. Subsequently, rats were euthanized and lenses were subjected to estimation of polyol accumulation, oxidative-nitrosative stress, NFκB activation, iNOS expression, ATP levels, ATPase activities, calpain activity and total protein levels. Cataract progression was delayed from the fifth week onwards in DT with lower mean of cataract stages compared to DV group (p<0.01) despite persistent hyperglycemia. Reduced cataractogenesis in DT group was accompanied with lower aldose reductase activity and sorbitol level compared to DV group (p<0.01). DT group also showed reduced NFκB activation, lower iNOS expression and reduced oxidative-nitrosative stress compared to DV group. Lenticular ATP and ATPase and calpain 2 activities in DT group were restored to normal. Consequently, soluble to insoluble protein ratio in DT group was higher compared to DV (p<0.05). In conclusion, preventive effect of topical tocotrienol on development of cataract in STZ-induced diabetic rats could be attributed to reduced lens aldose reductase activity, polyol levels and oxidative-nitrosative stress. These effects of tocotrienol invlove reduced NFκB activation, lower iNOS expression, restoration of ATP level, ATPase activities, calpain activity and lens protein levels. PMID:28350848

Reduction of oxidative-nitrosative stress underlies anticataract effect of topically applied tocotrienol in streptozotocin-induced diabetic rats.

PubMed

Abdul Nasir, Nurul Alimah; Agarwal, Renu; Sheikh Abdul Kadir, Siti Hamimah; Vasudevan, Sushil; Tripathy, Minaketan; Iezhitsa, Igor; Mohammad Daher, Aqil; Ibrahim, Mohd Ikraam; Mohd Ismail, Nafeeza

2017-01-01

Cataract, a leading cause of blindness, is of special concern in diabetics as it occurs at earlier onset. Polyol accumulation and increased oxidative-nitrosative stress in cataractogenesis are associated with NFκB activation, iNOS expression, ATP depletion, loss of ATPase functions, calpain activation and proteolysis of soluble to insoluble proteins. Tocotrienol was previously shown to reduce lens oxidative stress and inhibit cataractogenesis in galactose-fed rats. In current study, we investigated anticataract effects of topical tocotrienol and possible mechanisms involved in streptozotocin-induced diabetic rats. Diabetes was induced in Sprague Dawley rats by intraperitoneal injection of streptozotocin. Diabetic rats were treated with vehicle (DV) or tocotrienol (DT). A third group consists of normal, non-diabetic rats were treated with vehicle (NV). All treatments were given topically, bilaterally, twice daily for 8 weeks with weekly slit lamp monitoring. Subsequently, rats were euthanized and lenses were subjected to estimation of polyol accumulation, oxidative-nitrosative stress, NFκB activation, iNOS expression, ATP levels, ATPase activities, calpain activity and total protein levels. Cataract progression was delayed from the fifth week onwards in DT with lower mean of cataract stages compared to DV group (p<0.01) despite persistent hyperglycemia. Reduced cataractogenesis in DT group was accompanied with lower aldose reductase activity and sorbitol level compared to DV group (p<0.01). DT group also showed reduced NFκB activation, lower iNOS expression and reduced oxidative-nitrosative stress compared to DV group. Lenticular ATP and ATPase and calpain 2 activities in DT group were restored to normal. Consequently, soluble to insoluble protein ratio in DT group was higher compared to DV (p<0.05). In conclusion, preventive effect of topical tocotrienol on development of cataract in STZ-induced diabetic rats could be attributed to reduced lens aldose reductase activity, polyol levels and oxidative-nitrosative stress. These effects of tocotrienol invlove reduced NFκB activation, lower iNOS expression, restoration of ATP level, ATPase activities, calpain activity and lens protein levels.

Cortisol Response to Stress in Adults with Attention Deficit Hyperactivity Disorder

PubMed Central

Palomar, Gloria; Ferrer, Roser; Real, Alberto; Nogueira, Mariana; Corrales, Montserrat; Casas, Miguel; Ramos-Quiroga, Josep Antoni

2015-01-01

Background: Differences in the cortisol response have been reported between children exhibiting the inattentive and hyperactive/impulsive subtypes of attention deficit hyperactivity disorder. However, there is no such information about adults. The aim of the present study was to determine the possible differences between the combined and inattentive subtypes in the cortisol response to stress. Methods: Ninety-six adults with attention deficit hyperactivity disorder, 38 inattentive and 58 combined, without any medical or psychiatric comorbidities and 25 healthy controls were included. The Trier Social Stress Test was used to assess physiological stress responses. Clinical data and subjective stress levels, including the Perceived Stress Scale, were also recorded. Results: No significant differences in the cortisol response to the Trier Social Stress Test were found between patients and controls. However, albeit there were no basal differences, lower cortisol levels at 15 (P=.015), 30 (P=.015), and 45 minutes (P=.045) were observed in the combined compared with the inattentive subtype after the stress induction; these differences disappeared 60 minutes after the stress. In contrast, the subjective stress responses showed significant differences between attention deficit hyperactivity disorder patients and controls (P<.001), but no differences were seen between attention deficit hyperactivity disorder subtypes. In turn, subjective stress measures, such as the Perceived Stress Scale, positively correlated with the whole cortisol stress response (P<.027). Conclusions: Both the combined and inattentive attention deficit hyperactivity disorder adults exhibited a normal cortisol response to stress when challenged. Nevertheless, the inattentive patients displayed a higher level of cortisol after stress compared with the combined patients. Despite the differences in the cortisol response, adults with attention deficit hyperactivity disorder reported high levels of subjective stress in their every-day life. PMID:25782526

Cortisol Response to Stress in Adults with Attention Deficit Hyperactivity Disorder.

PubMed

Corominas-Roso, Margarida; Palomar, Gloria; Ferrer, Roser; Real, Alberto; Nogueira, Mariana; Corrales, Montserrat; Casas, Miguel; Ramos-Quiroga, Josep Antoni

2015-03-17

Differences in the cortisol response have been reported between children exhibiting the inattentive and hyperactive/impulsive subtypes of attention deficit hyperactivity disorder. However, there is no such information about adults. The aim of the present study was to determine the possible differences between the combined and inattentive subtypes in the cortisol response to stress. Ninety-six adults with attention deficit hyperactivity disorder, 38 inattentive and 58 combined, without any medical or psychiatric comorbidities and 25 healthy controls were included. The Trier Social Stress Test was used to assess physiological stress responses. Clinical data and subjective stress levels, including the Perceived Stress Scale, were also recorded. No significant differences in the cortisol response to the Trier Social Stress Test were found between patients and controls. However, albeit there were no basal differences, lower cortisol levels at 15 (P=.015), 30 (P=.015), and 45 minutes (P=.045) were observed in the combined compared with the inattentive subtype after the stress induction; these differences disappeared 60 minutes after the stress. In contrast, the subjective stress responses showed significant differences between attention deficit hyperactivity disorder patients and controls (P<.001), but no differences were seen between attention deficit hyperactivity disorder subtypes. In turn, subjective stress measures, such as the Perceived Stress Scale, positively correlated with the whole cortisol stress response (P<.027). Both the combined and inattentive attention deficit hyperactivity disorder adults exhibited a normal cortisol response to stress when challenged. Nevertheless, the inattentive patients displayed a higher level of cortisol after stress compared with the combined patients. Despite the differences in the cortisol response, adults with attention deficit hyperactivity disorder reported high levels of subjective stress in their every-day life. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Dynamics of neuroendocrine stress response: bistability, timing, and control of hypocortisolism

NASA Astrophysics Data System (ADS)

D'Orsogna, Maria; Chou, Tom; Kim, Lae

The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates numerous physiological processes. Disruptions in its activity are correlated with stress-related diseases such as post-traumatic stress disorder (PTSD) and major depressive disorder. We characterize ``normal'' and ``diseased'' states of the HPA axis as basins of attraction of a dynamical system describing the inhibition of peptide hormones, corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH), by circulating glucocorticoids such as cortisol (CORT). Our model includes ultradian oscillations, CRH self-upregulation of CRH release, and distinguishes two components of negative feedback by cortisol on circulating CRH levels: a slow direct suppression of CRH synthesis and a fast indirect effect on CRH release. The slow regulation mechanism mediates external stress-driven transitions between the stable states in novel, intensity, duration, and timing-dependent ways. We find that the timing of traumatic events may be an important factor in determining if and how the hallmarks of depressive disorders will manifest. Our model also suggests a mechanism whereby exposure therapy of stress disorders may act to normalize downstream dysregulation of the HPA axis.

Ecological comparison of cellular stress responses among populations - normalizing RT-qPCR values to investigate differential environmental adaptations.

PubMed

Koenigstein, Stefan; Pöhlmann, Kevin; Held, Christoph; Abele, Doris

2013-05-16

Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species' response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions.

Ecological comparison of cellular stress responses among populations – normalizing RT-qPCR values to investigate differential environmental adaptations

PubMed Central

2013-01-01

Background Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species’ response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Results Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. Conclusions This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions. PMID:23680017

Decrease of premature mothers' stress levels in the intensive care unit.

PubMed

Villamizar-Carvajal, B; Vargas-Porras, C; García-Corzo, J R

2018-04-03

To determine the effectiveness of the 'Creating Opportunities for Parent Empowerment' (COPE) programme in reducing stress levels in mothers of preterm infants in the neonatal intensive care unit (NICU). Clinical trial performed in Colombia, including mothers of infants younger than 34 weeks of gestation, hospitalized, without a history of premature delivery. The mothers with psychiatric illnesses, language disorders, history of use of psychoactive substances and whose newborns had a congenital malformation were excluded. A group intervened with the COPE programme and a control group with the usual institutional management were formed. Block randomization and masking was used for mothers and evaluators. The Parental Stress Scale was applied: NICU; Shapiro Wilk normality test, Wilcoxon test and covariance analysis (ANCOVA) with a significance level of p<.05, 95% CI. 66 mothers were enrolled. The two groups were similar in their demographic characteristics and in the initial stress level score. The control group increased the final stress score in two categories and the intervention group decreased final values in all categories. The initial and final scores of the overall general stress level showed a significant decrease (p<.01), but when comparing with the ANCOVA analysis there was no significant difference (p=.4). The COPE programme reduces the level of maternal stress, strengthening aspects during hospitalization, such as: emotional support, strengthening their role as caregivers and interaction with their babies and the development of a friendly environment in the NICU. Copyright © 2018. Publicado por Elsevier España, S.L.U.

Biomonitoring of physiological status and cognitive performance of underway submariners undergoing a novel watch-standing schedule

NASA Astrophysics Data System (ADS)

Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.

2005-05-01

Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.

Effects of chronic stress and high-fat diet on metabolic and nutritional parameters in Wistar rats.

PubMed

Bruder-Nascimento, Thiago; Campos, Dijon Henrique Salomé; Alves, Carlos; Thomaz, Samuel; Cicogna, Antônio Carlos; Cordellini, Sandra

2013-11-01

The aim of this study was assess the role of chronic stress on the metabolic and nutritional profile of rats exposed to a high-fat diet. Thirty-day-old male Wistar rats (70-100 g) were distributed into four groups: normal-diet (NC), chronic stress (St), high-fat diet (HD), and chronic stress/high-fat diet (HD/St). Stress consisted at immobilization during 15 weeks, 5 times per week, 1h per day; and exposure to the high-fat diet lasted 15 weeks. Nutritional and metabolic parameters were assessed. The level of significance was 5%. The HD group had final body weight, total fat, as well as insulin and leptin increased, and they were insulin resistant. The St and HD/St had arterial hypertension and increased levels of corticosterone. Stress blocked the effects of the high-fat diet. Chronic stress prevented the appearance of obesity. Our results help to clarify the mechanisms involved in metabolic and nutritional dysfunction, and contribute to clinical cases linked to stress and high-fat diet.

Fisetin Modulates Antioxidant Enzymes and Inflammatory Factors to Inhibit Aflatoxin-B1 Induced Hepatocellular Carcinoma in Rats

PubMed Central

Maurya, Brajesh Kumar; Trigun, Surendra Kumar

2016-01-01

Fisetin, a known antioxidant, has been found to be cytotoxic against certain cell lines. However, the mechanism by which it inhibits tumor growth in vivo remains unexplored. Recently, we have demonstrated that Aflatoxin-B1 (AFB1) induced hepatocarcinogenesis is associated with activation of oxidative stress-inflammatory pathway in rat liver. The present paper describes the effect of in vivo treatment with 20 mg/kg b.w. Fisetin on antioxidant enzymes vis-a-vis oxidative stress level and on the profile of certain proinflammatory cytokines in the hepatocellular carcinoma (HCC) induced by two doses of 1 mg/kg b.w. AFB1 i.p. in rats. The reduced levels of most of the antioxidant enzymes, coinciding with the enhanced level of reactive oxygen species in the HCC liver, were observed to regain their normal profiles due to Fisetin treatment. Also, Fisetin treatment could normalize the enhanced expression of TNFα and IL1α, the two proinflammatory cytokines, reported to be involved in HCC pathogenesis. These observations were consistent with the regression of neoplastic lesion and declined GST-pi (placental type glutathione-S-transferase) level, a HCC marker, in the liver of the Fisetin treated HCC rats. The findings suggest that Fisetin attenuates oxidative stress-inflammatory pathway of AFB1 induced hepatocarcinogenesis. PMID:26682000

Rock friction under variable normal stress

USGS Publications Warehouse

Kilgore, Brian D.; Beeler, Nicholas M.; Lozos, Julian C.; Oglesby, David

2017-01-01

This study is to determine the detailed response of shear strength and other fault properties to changes in normal stress at room temperature using dry initially bare rock surfaces of granite at normal stresses between 5 and 7 MPa. Rapid normal stress changes result in gradual, approximately exponential changes in shear resistance with fault slip. The characteristic length of the exponential change is similar for both increases and decreases in normal stress. In contrast, changes in fault normal displacement and the amplitude of small high-frequency elastic waves transmitted across the surface follow a two stage response consisting of a large immediate and a smaller gradual response with slip. The characteristic slip distance of the small gradual response is significantly smaller than that of shear resistance. The stability of sliding in response to large step decreases in normal stress is well predicted using the shear resistance slip length observed in step increases. Analysis of the shear resistance and slip-time histories suggest nearly immediate changes in strength occur in response to rapid changes in normal stress; these are manifested as an immediate change in slip speed. These changes in slip speed can be qualitatively accounted for using a rate-independent strength model. Collectively, the observations and model show that acceleration or deceleration in response to normal stress change depends on the size of the change, the frictional characteristics of the fault surface, and the elastic properties of the loading system.

Enhanced nitrogen diffusion induced by atomic attrition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ochoa, E.A.; Figueroa, C.A.; Czerwiec, T.

2006-06-19

The nitrogen diffusion in steel is enhanced by previous atomic attrition with low energy xenon ions. The noble gas bombardment generates nanoscale texture surfaces and stress in the material. The atomic attrition increases nitrogen diffusion at lower temperatures than the ones normally used in standard processes. The stress causes binding energy shifts of the Xe 3d{sub 5/2} electron core level. The heavy ion bombardment control of the texture and stress of the material surfaces may be applied to several plasma processes where diffusing species are involved.

Psychosocial stress and obesity among children residing in Kaunas City.

PubMed

Grazuleviciene, Regina; Petraviciene, Inga; Andrusaityte, Sandra; Balseviciene, Birute

2017-08-01

An unfavorable psychosocial environment has been associated with an increased prevalence of obesity among children. However, the available evidence on the association of low socioeconomic status and parent-child relationships with childhood obesity is scarce. The aim of our study was to conduct a simultaneous evaluation of the risks associated with pathological mother-child relationships, education level, and overweight/obesity among 4-6 year-old children. This cross-sectional study included 1489 mother-child pairs living in Kaunas city, Lithuania. The Parenting Stress Index was measured using the Parent-Child Dysfunctional Interaction subscale. Children's overweight/obesity was defined as the body mass index ≥18kg/m 2 . Logistic regression models as well as crude and adjusted odds ratios (OR) and their 95% confidence intervals (CI) were used to indicate the strength of the associations between childhood overweight/obesity, maternal education level, and psychosocial stress. The percentage of children with overweight/obesity rose with an increasing Parenting Stress Index score. The percentage of children with overweight/obesity in the group of parents with better education and normal mother-child relations was 6.0%, while in the group of less educated parents and pathological mother-child relations, this percentage reached 13.9%. The stratified multivariable model showed that, with reference to the group of better educated parents and normal mother-child relations, lower education level and pathological mother-child relations were statistically significant risk factors for overweight/obesity in 4-6 year-old children, increasing the OR of overweight/obesity (aOR: 2.43; 95% CI: 1.31-4.51). Pathological mother-child relations and maternal smoking mediated the effect of low maternal education level on children's BMI z-scores. Pathological mother-child relations, lower parental education levels, and smoking may be predictors of children's overweight/obesity. Measures oriented towards health behavior and psychosocial stress management should be encouraged among parents in order to decrease the risk of overweight/obesity in their children. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-oxidative effects of curcumin on immobilization-induced oxidative stress in rat brain, liver and kidney.

PubMed

Samarghandian, Saeed; Azimi-Nezhad, Mohsen; Farkhondeh, Tahereh; Samini, Fariborz

2017-03-01

Restraint stress has been indicated to induce oxidative damage in tissues. Several investigations have reported that curcumin (CUR) may have a protective effect against oxidative stress. The present study was designed to investigate the protective effects of CUR on restraint stress induced oxidative stress damage in the brain, liver and kidneys. For chronic restraint stress, rats were kept in the restrainers for 1h every day, for 21 consecutive days. The animals received systemic administrations of CUR daily for 21days. In order to evaluate the changes of the oxidative stress parameters following restraint stress, the levels of malondialdehyde (MDA), reduced glutathione (GSH), as well as antioxidant enzyme activities superoxide dismutase (SOD) glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) were measured in the brain, liver and kidney of rats after the end of restraint stress. The restraint stress significantly increased MDA level, but decreased the level of GSH and activists of SOD, GPx, GR, and CAT the brain, liver and kidney of rats in comparison to the normal rats (P<0.001). Intraperitoneal administration of CUR significantly attenuated oxidative stress and lipid peroxidation, prevented apoptosis, and increased antioxidant defense mechanism activity in the tissues versus the control group (P<0.05). This study shows that CUR can prevent restraint stress-induced oxidative damage in the brain, liver and kidney of rats and propose that CUR may be useful agents against oxidative stress in the tissues. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Normal stresses in semiflexible polymer hydrogels

NASA Astrophysics Data System (ADS)

Vahabi, M.; Vos, Bart E.; de Cagny, Henri C. G.; Bonn, Daniel; Koenderink, Gijsje H.; MacKintosh, F. C.

2018-03-01

Biopolymer gels such as fibrin and collagen networks are known to develop tensile axial stress when subject to torsion. This negative normal stress is opposite to the classical Poynting effect observed for most elastic solids including synthetic polymer gels, where torsion provokes a positive normal stress. As shown recently, this anomalous behavior in fibrin gels depends on the open, porous network structure of biopolymer gels, which facilitates interstitial fluid flow during shear and can be described by a phenomenological two-fluid model with viscous coupling between network and solvent. Here we extend this model and develop a microscopic model for the individual diagonal components of the stress tensor that determine the axial response of semiflexible polymer hydrogels. This microscopic model predicts that the magnitude of these stress components depends inversely on the characteristic strain for the onset of nonlinear shear stress, which we confirm experimentally by shear rheometry on fibrin gels. Moreover, our model predicts a transient behavior of the normal stress, which is in excellent agreement with the full time-dependent normal stress we measure.

Dietary nitrate and nitrite modulate blood and organ nitrite and the cellular ischemic stress response

PubMed Central

Raat, Nicolaas J.H.; Noguchi, Audrey C.; Liu, Virginia B.; Raghavachari, Nalini; Liu, Delong; Xu, Xiuli; Shiva, Sruti; Munson, Peter J.; Gladwin, Mark T.

2009-01-01

Dietary nitrate, found in abundance in green vegetables, can be converted to the cytoprotective molecule nitrite by oral bacteria, suggesting that nitrate and nitrite may represent active cardioprotective constituents of the Mediterranean diet. We therefore tested the hypothesis that dietary nitrate and nitrite levels modulate tissue damage and ischemic gene expression in a mouse liver ischemia-reperfusion model. We found that stomach content, plasma, heart and liver nitrite levels were significantly reduced after dietary nitrate and nitrite depletion, and could be restored to normal levels with nitrite supplementation in water. Remarkably, we confirmed that basal nitrite levels significantly reduced liver injury after ischemia-reperfusion. Consistent with an effect of nitrite on the post-translational modification of complex I of the mitochondrial electron transport chain, the severity of liver infarction was inversely proportional to complex I activity after nitrite repletion in the diet. The transcriptional response of dietary nitrite after ischemia was more robust than after normoxia, suggesting a hypoxic potentiation of nitrite-dependent transcriptional signaling. Our studies indicate that normal dietary nitrate and nitrite levels modulate ischemic stress responses and hypoxic gene expression programs, supporting the hypothesis that dietary nitrate and nitrite are cytoprotective components of the diet. PMID:19464364

Interdependency between mechanical parameters and afferent nerve discharge in remodeled diabetic Goto-Kakizaki rat intestine.

PubMed

Zhao, Jingbo; Yang, Jian; Liao, Donghua; Gregersen, Hans

2017-01-01

Gastrointestinal disorders are very common in diabetic patients, but the pathogenesis is still not well understood. Peripheral afferent nerves may be involved due to the complex regulation of gastrointestinal function by the enteric nervous system. We aimed to characterize the stimulus-response function of afferent fibers innervating the jejunum in the Goto-Kakizaki (GK) type 2 diabetic rat model. A key question is whether changes in afferent firing arise from remodeled tissue or from adaptive afferent processes. Seven 32-week-old male GK rats and seven age-matched normal Wistar rats were studied. Firing from mesenteric afferent nerves was recorded in excised jejunal segments of seven GK rats and seven normal Wistar rats during ramp test, stress relaxation test, and creep test. The circumferential stress-strain, spike rate increase ratio (SRIR), and single unit firing rates were calculated for evaluation of interdependency of the mechanical stimulations and the afferent nerve discharge. Elevated sensitivity to mechanical stimuli was found for diabetic nerve bundles and single unit activity ( P <0.05). The stress relaxed less in the diabetic intestinal segment ( P <0.05). Linear association between SRIR and the thickness of circumferential muscle layer was found at high stress levels as well as for SRIR and the glucose level. Altered viscoelastic properties and elevated mechanosensitivity were found in the GK rat intestine. The altered nerve signaling is related to muscle layer remodeling and glucose levels and may contribute to gastrointestinal symptoms experienced by diabetic patients.

Effect of stress perturbation on frictional instability: an experimental study

NASA Astrophysics Data System (ADS)

Yuanmin, H.; Shengli, M.

2017-12-01

We have performed a series of frictional experiments with direct shear configuration of three granite blocks by using a servo-controlled biaxial loading machine. In the experiments, a small- amplitude sine wave is modulated to shear and normal loading in order to study the effects of stress perturbation on stick-slip instability. The main results are as follows. Under the constant average normal stress and the constant loading point velocity in shear direction, the sample shows regular stick-slip behavior. After the stress perturbation is modulated, the correlation between the timing of stick-slip events and the perturbation increases with increasing the perturbation amplitude, and stress drop and interval time of stick-slip events tend to be discrete. This results imply that the change in Coulomb stress caused by stress perturbation may obviously change not only the occurrence time of earthquakes but also the earthquake magnitude. Both shear and normal stress perturbation can affect the stick-slip behavior, shear stress perturbation can only change the driving stress along fault, while the normal stress perturbation can change the contact state of asperities on the fault, so it's effect is more obviously. The stress perturbation can obviously affect acoustic emission (AE) activity during fault friction, which can trigger some AE events so that AE activity before stick-slip becomes stronger and occurs earlier. The perturbation in shear stress is more evident than that in normal stress in affecting AE activity, so we should not only pay attention to the magnitude of Coulomb stress changes caused by the perturbation, but also try to distinguish the stress changes are the shear stress changes or the normal stress changes, when study the effect of stress perturbation on fault friction.

A pivotal role for starch in the reconfiguration of 14C-partitioning and allocation in Arabidopsis thaliana under short-term abiotic stress.

PubMed

Dong, Shaoyun; Zhang, Joshua; Beckles, Diane M

2018-06-18

Plant carbon status is optimized for normal growth but is affected by abiotic stress. Here, we used 14 C-labeling to provide the first holistic picture of carbon use changes during short-term osmotic, salinity, and cold stress in Arabidopsis thaliana. This could inform on the early mechanisms plants use to survive adverse environment, which is important for efficient agricultural production. We found that carbon allocation from source to sinks, and partitioning into major metabolite pools in the source leaf, sink leaves and roots showed both conserved and divergent responses to the stresses examined. Carbohydrates changed under all abiotic stresses applied; plants re-partitioned 14 C to maintain sugar levels under stress, primarily by reducing 14 C into the storage compounds in the source leaf, and decreasing 14 C into the pools used for growth processes in the roots. Salinity and cold increased 14 C-flux into protein, but as the stress progressed, protein degradation increased to produce amino acids, presumably for osmoprotection. Our work also emphasized that stress regulated the carbon channeled into starch, and its metabolic turnover. These stress-induced changes in starch metabolism and sugar export in the source were partly accompanied by transcriptional alteration in the T6P/SnRK1 regulatory pathway that are normally activated by carbon starvation.

Shear-coupled grain-boundary migration dependence on normal strain/stress

NASA Astrophysics Data System (ADS)

Combe, N.; Mompiou, F.; Legros, M.

2017-08-01

In specific conditions, grain-boundary (GB) migration occurs in polycrystalline materials as an alternative vector of plasticity compared to the usual dislocation activity. The shear-coupled GB migration, the expected most efficient GB based mechanism, couples the GB motion to an applied shear stress. Stresses on GB in polycrystalline materials seldom have, however, a unique pure shear component. This work investigates the influence of a normal strain on the shear coupled migration of a Σ 13 (320 )[001 ] GB in a copper bicrystal using atomistic simulations. We show that the yield shear stress inducing the GB migration strongly depends on the applied normal stress. Beyond, the application of a normal stress on this GB qualitatively modifies the GB migration: while the Σ 13 (320 )[001 ] GB shear couples following the 〈110 〉 migration mode without normal stress, we report the observation of the 〈010 〉 mode under a sufficiently high tensile normal stress. Using the nudge elastic band method, we uncover the atomistic mechanism of this 〈010 〉 migration mode and energetically characterize it.

Evaluation of plasma reactive oxygen metabolites levels in obese subjects with periodontal disease.

PubMed

Suresh, Snophia; Mahendra, Jaideep; Sudhakar, Uma; Pradeep, A R; Singh, Gurdeep

2016-01-01

Obesity represents the systemic condition capable of influencing the onset and progression of periodontal disease. Obesity is associated with oxidative stress. Plasma level of reactive oxidative metabolites (ROMs) is measured as an indicator of oxidative stress in the body. The aim of this study is to assess and compare the plasma ROM levels in obese subjects with healthy and inflammatory periodontal status. Sixty subjects selected were grouped as 15 obese or overweight subjects with generalized chronic periodontitis, 15 obese or overweight subjects with generalized chronic gingivitis, 15 obese or overweight subjects with healthy periodontium, and 15 nonobese and healthy periodontium. The clinical periodontal parameters such as plaque index, gingival index, probing pocket depth, and clinical attachment level were measured. Blood samples were obtained to measure the plasma levels of ROM. In this study, obese subjects with chronic periodontitis (Group I) had mean plasma ROM levels (442.3 ± 15.65 Carratelli unit [CARR U]) showing 100% subjects with high oxidative stress. Obese subjects with chronic gingivitis (Group II) had mean plasma ROM levels (358.7 ± 20.61 CARR U) indicating 86.7% subjects with oxidative stress. Obese subjects with healthy periodontium (Group III) had 46.7% subjects with slight oxidative stress, and the mean ROM level was 320.2 ± 17.57. Nonobese subjects with healthy periodontium (Group IV) had 80% of subjects with normal oxidative stress and the mean plasma ROM level was 296.9 ± 20.35 CARR U. The intra- and inter-group comparison showed significant difference (P < 0.001). From our study, we report that obese subjects with periodontitis have more oxidative stress compared to obese subjects with healthy periodontium.

Perceived stress and well-being among dental hygiene and dental therapy students.

PubMed

Harris, M; Wilson, J C; Holmes, S; Radford, D R

2017-01-27

Aims To explore dental hygiene and dental therapy students' (DHDTS') perception of stress and well-being during their undergraduate education and establish base-line data for further studies of this group of dental professionals.Subjects and methods A questionnaire was distributed to Years 1, 2 and 3 DHDTS and final year outreach dental students (DS) (as a comparison group), at the University of Portsmouth Dental Academy (UPDA), during summer 2015. Data were collected on students' perception of levels of stress and well-being. Statistical analyses were undertaken using SPSS software. Mann-Whitney U tests with Bonferroni corrections were used and the level for a statistically significant difference was set at p <0.002.Results A response rate of 81% (DHDTS) and 85% (DS) was achieved. Clinical factors and academic work were perceived as stressful for both DHDTS and DS, with no significant difference between the groups. The majority of respondents reported levels of depression, anxiety, and stress to be within the normal range. All students reported high levels of positive well-being, with DHDTS scoring significantly higher than DS in the dimensions of personal growth, purpose in life, self-acceptance and positive relations with others (p <0.002).Conclusions DHDTS and DS identified sources of stress within their undergraduate education, but also perceived themselves as positively-functioning individuals.

Supplementation of α-Tocopherol Attenuates Minerals Disturbance, Oxidative Stress and Apoptosis Occurring in Favism.

PubMed

Koriem, Khaled M M; Arbid, Mahmoud S; Gomaa, Nawal E

2017-10-01

The favism is a metabolic disease that characterized with an acute hemolytic anemia where α-tocopherol is a type of tocopherol accumulated inside the human body. The objective of such a study was established to evaluate the effect of α-tocopherol in favism disorders. A total of 75 human cases were divided into 5 groups as follow; group 1 normal cases without any treatment and group 2 normal cases orally administrated α-tocopherol (200 mg/kg) once a day over 30 days period. Group 3 favism patients without any treatment. Groups 4 and 5 favism patients orally administrated 100 and 200 mg α-tocopherol/kg, respectively once a day over 30 days period. The results obtained revealed that oral administration of α-tocopherol into normal cases over 30 days period did not induce any biological change. In favism, hemoglobin, hematocrit, red and white blood cells, serum glucose, glucose-6-phosphate dehydrogenase, total protein, albumin, globulin, aspartate and alanine aminotransferases, blood glutathione, superoxide dismutase, glutathione peroxidase and serum calcium, phosphorous, sodium, potassium and chloride levels were significantly decreased. On the other hand, serum alkaline phosphatase, bilirubin, selenium, zinc, manganese, copper and iron, malondialdehyde levels showed significant increase in favism. Supplementation with α-tocopherol into favism restores all the above mentioned parameters to approach the normal levels. Also, α-tocopherol has anti-apoptotic effect in favism. In conclusion, α-tocopherol attenuates minerals disturbance, oxidative stress and apoptosis occurring in favism.

Beneficial effect of fluoxetine treatment aganist psychological stress is mediated by increasing BDNF expression in selected brain areas

PubMed Central

Li, Gongying; Jing, Ping; Liu, Zhidong; Li, Zhiruo; Ma, Hongxia; Tu, Wenzhen; Zhang, Wei; Zhuo, Chuanjun

2017-01-01

SSRI antidepressant fluoxetine is widely used to treat psychological stress related disorders, however the underlying working mechanisms is not fully understood, as SSRIs can rapidly increase the extracellular serotonin levels but it normally takes weeks to reveal their therapeutic effect in the stress-related psychological disorders. Our previous study demonstrated that purely psychological stress without any physic stimuli induces a biphasic change in the expression of brain-derived neurotrophic factor (BDNF), which immediately decrease and then gradually increase after the stress; and that the latter BDNF increase in response to the psychological stress involves the activation of serotonin system. To investigate the role of BDNF in the fluoxetine treatment for stress-related psychological disorders, we examined the mRNA and protein levels of BDNF in the brain of Sprague-Dawley (SD) rats, which were pretreated with fluoxetine at 10 mg/kg or vehicle solution for 14 days, over 24 hour after an acute psychological stress exposure. In situ hybridization and immunohistochemistry were performed to detect the expression of BDNF at different time points in various brain regions after the psychological stress. We found that fluoxetine treatment completely blocked the BDNF decrease induced by the psychological stress, and also enhanced the gradual increase in the expression of BDNF in most of the brain regions except VTA after the psychological stress. The results suggest that the enhancement in BDNF levels induced by chronic fluoxetine treatment mediates the therapeutic effect against psychological stress. PMID:29050222

Effects of stress in early life on immune functions in rats with asthma and the effects of music therapy.

PubMed

Lu, Yanxia; Liu, Meng; Shi, Shousen; Jiang, Hong; Yang, Lejin; Liu, Xin; Zhang, Qian; Pan, Fang

2010-06-01

Although studies have shown that psychological stress has detrimental effects on bronchial asthma, there are few objective data on whether early-life stress, as early postnatal psychosocial environment, has a long-lasting effect on adult asthma and the potential pathophysiologic mechanism. This study aims to examine the effects on immune function and hypothalamic-pituitary-adrenal (HPA) axis responses in adult asthmatic rats that experienced stress in early life and the potential ameliorative effects of music therapy on these parameters. Forty male Wistar rat pups were randomly assigned to the asthma group, the adulthood-stressed asthma group, the childhood-stressed asthma group, the music group, and the control group. Restraint stress and Mozart's Sonata K.448 were applied to ovalbumin (OVA)-induced asthmatic rats to establish psychological stress and music therapy models. The levels of serum corticosterone were examined in both childhood after stress and adulthood after OVA challenge. Immune indicators in blood, lung, and brain tissues were measured after the last OVA challenge. Stress in both childhood and adulthood resulted in increases in leukocyte and eosinophil numbers and serum interleukin (IL)-4 levels. The adulthood-stressed group demonstrated increased corticosterone levels after challenge, whereas the childhood-stressed group showed increased corticosterone concentration in childhood but decreased level in adulthood. Central IL-1beta exhibited a similar tendency. Music group rats showed reduced serum IL-4 and corticosterone. Stress in childhood and adulthood resulted in different HPA axis responsiveness in the exacerbation of markers of asthma. These data provide the first evidence of the long-term normalizing effects of music on asthmatic rats.

Left ventricular wall stress and sarcoplasmic reticulum Ca(2+)-ATPase gene expression in renal hypertensive rats: dose-dependent effects of ACE inhibition and AT1-receptor blockade.

PubMed

Zierhut, W; Studer, R; Laurent, D; Kästner, S; Allegrini, P; Whitebread, S; Cumin, F; Baum, H P; de Gasparo, M; Drexler, H

1996-05-01

Cardiac hypertrophy is associated with altered Ca2+ handling and may predispose to the development of LV dysfunction and cardiac failure. At the cellular level, the re-expression of ANF represents a well-established marker of myocyte hypertrophy while the decreased expression of the sarcoplasmatic reticulum (SR) Ca(2+)-ATPase is thought o play a crucial role in the alterations of Ca2+ handling and LV function. We assessed the dose-dependent effect of chronic ACE inhibition or AT1 receptor blockade on cardiac function in relation to the cardiac expression of the SR Ca(2+)-ATPase and ANF. Renal hypertensive rats (2K-1C) were treated for 12 weeks with three different doses of the ACE inhibitor benazepril, the AT1-receptor antagonist valsartan (each drug 0.3, 3, and 10 mg/kg per day i.p.) or placebo. LV dimensions, hypertrophy and wall stress were determined in vivo by magnetic resonance imaging and the gene expressions of ANF and SR Ca(2+)-ATPase were quantified by Northern blot. Low doses of both drugs did not affect blood pressure, hypertrophy, systolic wall stress and the ANF and SR Ca(2+)-ATPase gene expression. High doses of each drug reduced systolic blood pressure, wall stress, and LV hypertrophy to a similar extent and to values comparable to normotensive, age-matched rats. In addition, high dose treatment reduced LV end-systolic and end-diastolic volume as compared to untreated 2K-1C animals and normalized the mRNA levels of both ANF and SR Ca(2+)-ATPase (as compared to normotensive animals). We conclude that in this model, high doses of ACE inhibition and AT1-receptor blockade are necessary to normalize systolic blood pressure, LV hypertrophy and systolic LV wall stress which, in turn, is associated with restoration of a normal cardiac phenotype with respect to SR Ca(2+)-ATPase and ANF and normalization of cardiac function.

Evidence against a direct role for oxidative stress in cadmium-induced axial malformation in the chick embryo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Jennifer, E-mail: jennifer.thompson@ucd.i; Doi, Takashi; The Children's Research Centre, Our Lady's Children's Hospital, Dublin 12

Cadmium (Cd) is a powerful inducer of oxidative stress. It also causes ventral body wall defects in chick embryos treated at Hamburger-Hamilton stages 16-17. By measuring malondialdehyde levels (TBARS method) and cotreating with antioxidants (tempol, ascorbate, and N-acetylcysteine), we sought to determine if oxidative stress were directly related to teratogenesis. We also investigated the expression of mRNAs for antioxidant enzymes superoxide dismutase (SOD) -1 and -2, catalase (CAT), and glutathione peroxidase (GPx). RT-PCR showed reductions in SOD-1, SOD-2, and CAT 1 hour after treatment with Cd. MDA levels increased 4 hours after Cd, and remained elevated 24 hours after treatment.more » Of the antioxidants, only N-acetylcysteine reduced MDA levels to control values. Nonetheless, no antioxidant could reduce embryo lethality or malformation rates. Furthermore, MDA levels 24 hours after treatment were identical in malformed and normal embryos exposed to Cd. Hence, we conclude that oxidative stress may not have a direct role in Cd teratogenesis.« less

Glucocorticoids, stress, and fertility.

PubMed

Whirledge, S; Cidlowski, J A

2010-06-01

Modifications of the hypothalamo-pituitary-adrenal axis and associated changes in circulating levels of glucocorticoids form a key component of the response of an organism to stressful challenges. Increased levels of glucocorticoids promote gluconeogenesis, mobilization of amino acids, and stimulation of fat breakdown to maintain circulating levels of glucose necessary to mount a stress response. In addition to profound changes in the physiology and function of multiple tissues, stress and elevated glucocorticoids can also inhibit reproduction, a logical effect for the survival of self. Precise levels of glucocorticoids are required for proper gonadal function; where the balance is disrupted, so is fertility. Glucocorticoids affect gonadal function at multiple levels in hypothalamo-pituitary-gonadal axis: 1) the hypothalamus (to decrease the synthesis and release of gonadotropin-releasing hormone [GnRH]); 2) the pituitary gland (to inhibit the synthesis and release of luteinizing hormone [LH] and follicle stimulating hormone [FSH]); 3) the testis/ovary (to modulate steroidogenesis and/or gametogenesis directly). Furthermore, maternal exposure to prenatal stress or exogenous glucocorticoids can lead to permanent modification of hypothalamo-pituitary-adrenal function and stress-related behaviors in offspring. Glucocorticoids are vital to many aspects of normal brain development, but fetal exposure to superabundant glucocorticoids can result in life-long effects on neuroendocrine function. This review focuses on the molecular mechanisms believed to mediate glucocorticoid inhibition of reproductive functions and the anatomical sites at which these effects take place.

Prohibitin as an oxidative stress biomarker in the eye

PubMed Central

Lee, Hyunju; Arnouk, Hilal; Sripathi, Srinivas; Chen, Ping; Zhang, Ruonan; Hunt, Richard C.; Hrushesky, William J. M.; Chung, Hyewon; Lee, Sung Haeng; Jahng, Wan Jin

2016-01-01

Identification of biomarker proteins in the retina and the retinal pigment epithelium (RPE) under oxidative stress may imply new insights into signaling mechanisms of retinal degeneration at the molecular level. Proteomic data from an in vivo mice model in constant light and an in vitro oxidative stress model are compared to controls under normal conditions. Our proteomic study shows that prohibitin is involved in oxidative stress signaling in the retina and RPE. The identity of prohibitin in the retina and the RPE was studied using 2D electrophoresis, immunohistochemistry, western blot, and mass spectrometry analysis. Comparison of expression levels with apoptotic markers as well as translocation between mitochondria and the nucleus imply that the regulation of prohibitin is an early signaling event in the RPE and retina under oxidative stress. Immunohistochemical analysis of murine aged and diabetic eyes further suggests that the regulation of prohibitin in the RPE/retina is related to aging- and diabetes-induced oxidative stress. Our proteomic approach implies that prohibitin in the RPE and the retina could be a new biomarker protein of oxidative stress in aging and diabetes. PMID:20832420

Prohibitin as an oxidative stress biomarker in the eye.

PubMed

Lee, Hyunju; Arnouk, Hilal; Sripathi, Srinivas; Chen, Ping; Zhang, Ruonan; Bartoli, Manuela; Hunt, Richard C; Hrushesky, William J M; Chung, Hyewon; Lee, Sung Haeng; Jahng, Wan Jin

2010-12-01

Identification of biomarker proteins in the retina and retinal pigment epithelium (RPE) under oxidative stress may imply new insights into signaling mechanisms of retinal degeneration at the molecular level. Proteomic data from an in vivo mice model in constant light and an in vitro oxidative stress model are compared to controls under normal conditions. Our proteomic study shows that prohibitin is involved in oxidative stress signaling in the retina and RPE. The identity of prohibitin in the retina and RPE was studied using 2D electrophoresis, immunohistochemistry, western blot, and mass spectrometry analysis. Comparison of expression levels with apoptotic markers as well as translocation between mitochondria and the nucleus imply that the regulation of prohibitin is an early signaling event in the RPE and retina under oxidative stress. Immunohistochemical analysis of murine aged and diabetic eyes further suggests that the regulation of prohibitin in the RPE/retina is related to aging- and diabetes-induced oxidative stress. Our proteomic approach implies that prohibitin in the RPE and the retina could be a new biomarker protein of oxidative stress in aging and diabetes. Copyright © 2010 Elsevier B.V. All rights reserved.

[Study of the occupational stress norm and it's application for the executive group and administrative support group].

PubMed

Yang, Xin-wei; Wang, Zhi-ming; Jin, Tai-yi; Lan, Ya-jia

2006-07-01

A study of the occupational stress norm and it's application for the executive group and administrative support group. In this study, cross-sectional study method is used, and a synthetic way of sorting and randomized sampling is adopted to deal with research targets (263 executive group, 569 administrative support group). Descriptive statistics for OSI-R scale scores for the executive group, administrative support group were modulated. Scale raw score to T-score conversion tables derived from the OSI-R normative sample for executive group, administrative support group were established. OSI-R profile from for executive group, administrative support group were established. For the ORQ and PSQ scales, scores at or above 70 indicate a strong levels of maladaptive stress and strain. Score inthe range of 60 to 69 suggest middle levels of maladaptive stress and strain. Score in the range of 40 to 59 indicate normal levels of stress and strain. Score below 40 indicate a relative absence of occupational stress and strain. For the PRQ scales, score below 30 indicate a significant lack of coping resources. Score in the range of 30 to 39 suggest middle deficits in coping resources. Score in the range of 40 to 59 indicate average coping resources. Scores at or above 60 indicate a strong levels of coping resources. Based on occupational Stress norm, raw score to T-score conversion tables, OSI-R profile form and classification criterion, we could estimate the level of occupation stress, stressor, strain and coping resources in different occupation. In addition, we combined subjective and objective environment match model of occupational stress. The various individual and organizational intervention measures should be taken to reduce the occupational stress and to increase coping so as to improve the work ability.

Relationship between oxidative stress and "burning mouth syndrome" in female patients: a scientific hypothesis.

PubMed

Tatullo, M; Marrelli, M; Scacco, S; Lorusso, M; Doria, S; Sabatini, R; Auteri, P; Cagiano, R; Inchingolo, F

2012-09-01

Burning Mouth Syndrome (BMS) is characterized by burning sensation and pain in the mouth with or without inflammatory signs and specific lesions. Aim of the present study was to investigate about a possible correlation between the Burning Mouth Syndrome and oxidative stress. We recruited 18 healthy female patients between 54 and 68 years of age with a diagnosis of Burning Mouth Syndrome. Oxidative stress assessment was performed by means of an integrated analytical system composed of a photometer and a mini-centrifuge (FRAS4, H and D s.r.l., Parma, Italy). Samples of whole capillary blood were taken by a finger puncture in a heparinized tube and immediately centrifuged; a small amount of samples plasma (10 microL) were thereafter tested for total oxidant capacity (d-ROMs test) and biological antioxidant potential as iron-reducing activity (BAP test) (Diacron International s.r.l., Grosseto, Italy). Our results indicate that female patients affected by Burning Mouth Syndrome show significantly different d-ROMs and BAP levels, similar to those present in oxidative stress condition with respect to the general population. It was also emphasized that, after the most painful phase, the levels representing the present oxidative stress, progressively return to normal, even if still significantly higher 7 days after, with respect to the normal population. No similar study was performed up to now. This study confirms the effectiveness of antioxidant treatments in the patients affected by BMS, in order to prevent or decrease the onset of oxidative stress and the consequent increased risk of oxidative-related systemic diseases.

Maternal stress during pregnancy increases neonatal allergy susceptibility: role of glucocorticoids.

PubMed

Lim, Robert; Fedulov, Alexey V; Kobzik, Lester

2014-07-15

We sought to test experimentally whether maternal stress can promote susceptibility to development of asthma-like allergic airways disease in offspring. Normal pregnant mice (day 15) were subjected to a single restraint stress exposure. We subsequently tested their offspring for the development of airway hyperreactivity (AHR) and allergic airway inflammation (AI), after an intentionally suboptimal sensitization protocol. The offspring of stressed mothers showed levels of AI and enhanced airway responses to methacholine comparable to those seen in fully sensitized and challenged positive control animals; in contrast, minimal effects were seen in control offspring. Restraint stress caused a rapid and large increase in plasma corticosterone levels. Maternal treatment with dexamethasone on day 15 of pregnancy mimicked the stress effect and reproduced the AI and AHR outcomes, whereas blockade of the stress-induced corticosterone surge with metyrapone pretreatment of pregnant mice abrogated the effect. We conclude that stress-triggered glucocorticoids during pregnancy can increase susceptibility to allergy in offspring. Because inflammation typically includes a stress hormone response, the results also suggest a common pathway by which various injurious exposures during pregnancy might increase offspring susceptibility to asthma. Copyright © 2014 the American Physiological Society.

Tinnitus and other auditory problems - occupational noise exposure below risk limits may cause inner ear dysfunction.

PubMed

Lindblad, Ann-Cathrine; Rosenhall, Ulf; Olofsson, Åke; Hagerman, Björn

2014-01-01

The aim of the investigation was to study if dysfunctions associated to the cochlea or its regulatory system can be found, and possibly explain hearing problems in subjects with normal or near-normal audiograms. The design was a prospective study of subjects recruited from the general population. The included subjects were persons with auditory problems who had normal, or near-normal, pure tone hearing thresholds, who could be included in one of three subgroups: teachers, Education; people working with music, Music; and people with moderate or negligible noise exposure, Other. A fourth group included people with poorer pure tone hearing thresholds and a history of severe occupational noise, Industry. Ntotal = 193. The following hearing tests were used: - pure tone audiometry with Békésy technique, - transient evoked otoacoustic emissions and distortion product otoacoustic emissions, without and with contralateral noise; - psychoacoustical modulation transfer function, - forward masking, - speech recognition in noise, - tinnitus matching. A questionnaire about occupations, noise exposure, stress/anxiety, muscular problems, medication, and heredity, was addressed to the participants. Forward masking results were significantly worse for Education and Industry than for the other groups, possibly associated to the inner hair cell area. Forward masking results were significantly correlated to louder matched tinnitus. For many subjects speech recognition in noise, left ear, did not increase in a normal way when the listening level was increased. Subjects hypersensitive to loud sound had significantly better speech recognition in noise at the lower test level than subjects not hypersensitive. Self-reported stress/anxiety was similar for all groups. In conclusion, hearing dysfunctions were found in subjects with tinnitus and other auditory problems, combined with normal or near-normal pure tone thresholds. The teachers, mostly regarded as a group exposed to noise below risk levels, had dysfunctions almost identical to those of the more exposed Industry group.

Tinnitus and Other Auditory Problems – Occupational Noise Exposure below Risk Limits May Cause Inner Ear Dysfunction

PubMed Central

Lindblad, Ann-Cathrine; Rosenhall, Ulf; Olofsson, Åke; Hagerman, Björn

2014-01-01

The aim of the investigation was to study if dysfunctions associated to the cochlea or its regulatory system can be found, and possibly explain hearing problems in subjects with normal or near-normal audiograms. The design was a prospective study of subjects recruited from the general population. The included subjects were persons with auditory problems who had normal, or near-normal, pure tone hearing thresholds, who could be included in one of three subgroups: teachers, Education; people working with music, Music; and people with moderate or negligible noise exposure, Other. A fourth group included people with poorer pure tone hearing thresholds and a history of severe occupational noise, Industry. Ntotal = 193. The following hearing tests were used: − pure tone audiometry with Békésy technique, − transient evoked otoacoustic emissions and distortion product otoacoustic emissions, without and with contralateral noise; − psychoacoustical modulation transfer function, − forward masking, − speech recognition in noise, − tinnitus matching. A questionnaire about occupations, noise exposure, stress/anxiety, muscular problems, medication, and heredity, was addressed to the participants. Forward masking results were significantly worse for Education and Industry than for the other groups, possibly associated to the inner hair cell area. Forward masking results were significantly correlated to louder matched tinnitus. For many subjects speech recognition in noise, left ear, did not increase in a normal way when the listening level was increased. Subjects hypersensitive to loud sound had significantly better speech recognition in noise at the lower test level than subjects not hypersensitive. Self-reported stress/anxiety was similar for all groups. In conclusion, hearing dysfunctions were found in subjects with tinnitus and other auditory problems, combined with normal or near-normal pure tone thresholds. The teachers, mostly regarded as a group exposed to noise below risk levels, had dysfunctions almost identical to those of the more exposed Industry group. PMID:24827149

Therapeutic Ultrasound in Navicular Stress Injuries in Elite Track and Field Athletes.

PubMed

Malliaropoulos, Nikolaos; Alaseirlis, Dimosthenis; Konstantinidis, George; Papalada, Agapi; Tsifountoudis, Ioannis; Petras, Kosmas; Maffulli, Nicola

2017-05-01

To ascertain whether therapeutic ultrasound (TUS) can be used to assess the progression of conservative management in navicular stress injuries. This is a prospective, clinical case series. Level of evidence IV. All participants were examined and followed up in a private Sports Injury Clinic. Ten elite track and field athletes with severe dorsal midfoot pain over the navicular bone participated in this study. All patients underwent both TUS and magnetic resonance imaging (MRI) evaluation. The painful threshold of TUS on initial evaluation was a mean of 0.707 ± 149 W/cm, and MRI detected a navicular stress injury in all patients. The athletes received conservative treatment and underwent sequential TUS evaluations at 4, 8, 12 and 16 weeks. Therapeutic ultrasound pain threshold values were recorded, and the patients were additionally asked to grade local tenderness on a Visual Analogue Scale. Time to return to play was also recorded. The level of pain produced by the application of TUS on a navicular stress fracture seemed to correlate well with Visual Analogue Scale scores and the grade of fracture demonstrated on MRI. The initial low TUS painful mean value increased to a normal mean value of 1.97 ± 0.067 W/cm by 16 weeks. When clinical and TUS findings had returned to normal, the patients were allowed to return to sports activities, with no recurrences experienced during the study period. The production of pain associated with the application of TUS on a navicular stress fracture is a safe and reproducible method of monitoring the resolution of these fractures. We have used it successfully in making return-to-play decisions for elite level track and field athletes.

[The scale and application of the norm of occupational stress on the professionals in Chengdu and Chongqing area].

PubMed

Zeng, Fan-Hua; Wang, Zhi-Ming; Wang, Mian-Zhen; Lan, Ya-Jia

2004-12-01

To establish the scale of the norm of occupational stress on the professionals and put it into practice. T scores were linear transformations of raw scores, derived to have a mean of 50 and a standard deviation of 10. The scale standard of the norm was formulated in line with the principle of normal distribution. (1) For the occupational role questionnaire (ORQ) and personal strain questionnaire (PSQ) scales, high scores suggested significant levels of occupational stress and psychological strain, respectively. T scores >/= 70 indicated a strong probability of maladaptive stress, debilitating strain, or both. T scores in 60 approximately 69 suggested mild levels of maladaptive stress and strain, and in 40 approximately 59 were within one standard deviation of the mean and should be interpreted as being within normal range. T scores < 40 indicated a relative absence of occupational stress or psychological strain. For the personal resources questionnaire (PRQ) scales, high scores indicated highly developed coping resources. T scores < 30 indicated a significant lack of coping resources. T scores in 30 approximately 39 suggested mild deficits in coping skills, and in 40 approximately 59 indicated average coping resources, where as higher scores (i.e., >/= 60) indicated increasingly strong coping resources. (2) This study provided raw score to T-score conversion tables for each OSI-R scale for the total normative sample as well as for gender, and several occupational groups, including professional engineer, professional health care, economic business, financial business, law, education and news. OSI-R profile forms for total normative samples, gender and occupation were also offered according to the conversion tables. The norm of occupational stress can be used as screening tool, organizational/occupational assessment, guide to occupational choice and intervention measures.

Water and Salt Stresses, Kinetin and Protein Synthesis in Tobacco Leaves 1

PubMed Central

Ben-Zioni, Aliza; Itai, C.; Vaadia, Y.

1967-01-01

The capacity of tobacco (Nicotiana rustica) leaf discs to incorporate l-leucine 14C into proteins was measured. Leaf discs were obtained from plants which experienced soil water depletion, or which were exposed to a saline or osmotic stress in the root medium. The stresses were brief of relatively short duration and water potential did not decrease below 4 bars in the root media. Leaf discs were sampled 2 hours after stress removal, achieved by reirrigation, or replacement of saline and osmotic solutions with normal nutrient solution. Plants were always turgid when leaves were sampled. All stressed tissues showed reduced capacity to incorporate l-leucine 14C into protein. The reduction was about 50% and could not be attributed either to reduced uptake into the discs, or to possible isotopic dilution. Incorporation decreased progressively with leaf age in control discs as well as in stressed leaf discs. At all ages tested, incorporation in stressed discs was lower than that of the control. Full recovery of incorporation capacity in stressed discs was obtained when discs were sampled 72 hours after stress removal but not earlier. Kinetin pretreatment prior to incubation with labelled leucine partially restored incorporation in stressed discs. The differences in response to kinetin of stressed and control discs suggest a lower endogenous level of cytokinins in the stressed discs. The results were qualitatively similar regardless of the kind of stress given to the plants during pretreatment. This supports the hypothesis that the normal supply of root cytokinins is important in shoot metabolism. PMID:16656515

Uptake and metabolism of ammonium and nitrate in response to drought stress in Malus prunifolia.

PubMed

Huang, Linlin; Li, Mingjun; Zhou, Kun; Sun, Tingting; Hu, Lingyu; Li, Cuiying; Ma, Fengwang

2018-06-01

Using a hydroponics culture system, we monitored morphological, physiological, and molecular changes in Malus prunifolia seedlings when drought conditions induced by 5% polyethylene glycol (PEG) were combined with a low or normal supply of N (0.05 mM or 1 mM NH 4 NO 3 , respectively). Under either nutrient level, drought stress negatively inhibited seedling performance, as manifested by reduced photosynthesis and biomass production, decreased accumulations of total N, and inhibited root growth. Concentrations of NO 3 - and NH 4 + and the activities of enzymes involved in N metabolism (nitrate reductase, glutamine synthetase, and glutamate synthase) were also significantly decreased under drought stress. The net influx of NO 3 - at the surface of the fine roots declined while that of NH 4 + rose markedly, suggesting that the latter may play a more important role in improving drought tolerance in M. prunifolia. Consistently, two ammonium transporters (AMT1;2 and AMT4;2) were notably up-regulated in response to drought stress, whereas most genes related to nitrate uptake, reduction, and N metabolism were down-regulated. At the normal N level, PEG-treated plants showed higher values for biomass production, root growth, and N uptake/reduction when compared with plants exposed to the lower N supply. These results suggest that the negative effect of drought stress on M. prunifolia may be alleviated when more nitrogen is available. Copyright © 2018. Published by Elsevier Masson SAS.

22q11.2 deletion syndrome: behaviour problems of children and adolescents and parental stress.

PubMed

Briegel, W; Schneider, M; Schwab, K Otfried

2008-11-01

22q11.2 deletion syndrome can be associated with a variety of somatic symptoms, developmental delays and psychiatric disorders. At present, there is little information on behaviour problems, parental stress and possible relations between these factors. Therefore, this study investigates behaviour problems of children and adolescents with 22q11.2DS, and their primary caregivers' stress. Parents of 4-17 year old subjects known to the German 22q11.2 deletion syndrome foundation were anonymously asked to fill out several questionnaires, e.g. the Child Behavior Checklist 4-18 (CBCL/4-18). The primary caregivers of 77/126 children [43 males, 34 females, mean age: 8;0 (4;0-16;11) years] sent back filled-out questionnaires. Forty-six of 76 subjects were rated as clinical on at least one of the CBCL-scales. Males had significantly higher scores on the total problems scale and the internalizing problems scale than females. The patients' age correlated with several CBCL-scales. Eleven of 49 subjects were suspicious of an autism spectrum disorder. Compared with the general population, but not with other parents of mentally and/or physically handicapped children, the primary caregivers experienced higher levels of stress, but showed normal life satisfaction. In spite of high rates of clinical behaviour problems among children and adolescents with 22q11.2DS and despite increased parental stress, most primary caregivers seem to have effective coping strategies, e.g. partnership support, to sustain normal levels of life satisfaction.

Development of Alopecia Areata Is Associated with Higher Central and Peripheral Hypothalamic–Pituitary–Adrenal Tone in the Skin Graft Induced C3H/HeJ Mouse Model

PubMed Central

Zhang, Xingqi; Yu, Mei; Yu, Wayne; Weinberg, Joanne; Shapiro, Jerry; McElwee, Kevin J.

2016-01-01

The relationship of the stress response to the pathogenesis of alopecia areata (AA) was investigated by subjecting normal and skin graft-induced, AA-affected C3H/HeJ mice to light ether anesthesia or restraint stress. Plasma corticosterone (CORT), adrenocorticotropic hormone (ACTH), and estradiol (E2) levels were determined by RIA, whereas gene expression in brains, lymphoid organs, and skin was measured by quantitative RT-PCR for corticotropin-releasing hormone (Crh), arginine vasopressin (Avp), proopiomelanocortin (Pomc), glucocorticoid receptor (Nr3c1), mineralo corticoid receptor (Nr3c2), corticotropin-releasing hormone receptor types 1 and 2 (Crhr1, Crhr2), interleukin-12 (Il12), tumor necrosis factor-α (Tnfα), and estrogen receptors type-1 (Esr1) and type-2 (Esr2). AA mice had a marked increase in hypothalamic–pituitary–adrenal (HPA) tone and activity centrally, and peripherally in the skin and lymph nodes. There was also altered interaction between the adrenal and gonadal axes compared with that in normal mice. Stress further exacerbated changes in AA mouse HPA activity both centrally and peripherally. AA mice had significantly blunted CORT and ACTH responses to acute ether stress (physiological stressor) and a deficit in habituation to repeated restraint stress (psychological stressor). The positive correlation of HPA hormone levels with skin Th1 cytokines suggests that altered HPA activity may occur as a consequence of the immune response associated with AA. PMID:19020552

Fault stability under conditions of variable normal stress

USGS Publications Warehouse

Dieterich, J.H.; Linker, M.F.

1992-01-01

The stability of fault slip under conditions of varying normal stress is modelled as a spring and slider system with rate- and state-dependent friction. Coupling of normal stress to shear stress is achieved by inclining the spring at an angle, ??, to the sliding surface. Linear analysis yields two conditions for unstable slip. The first, of a type previously identified for constant normal stress systems, results in instability if stiffness is below a critical value. Critical stiffness depends on normal stress, constitutive parameters, characteristic sliding distance and the spring angle. Instability of the first type is possible only for velocity-weakening friction. The second condition yields instability if spring angle ?? <-cot-1??ss, where ??ss is steady-state sliding friction. The second condition can arise under conditions of velocity strengthening or weakening. Stability fields for finite perturbations are investigated by numerical simulation. -Authors

[Prospective cohort study on the occupational stress and mental disorder among the oilfield workers in Xinjiang Autonomous Region in 2013-2015].

PubMed

Han, Rui; Shi, Haohua; Chen, Yulu; Lian, Yulong; Liu, Jiwen

2018-01-01

To explore the relationship between occupational stress and psychological disorder among oilfield workers. In 2013, 1485 psychological normal oilfield workers using the stratified cluster sampling in Xinjiang Autonomous Region were investigated, and the follow-up was conducted in 2015. Occupational stress and mental health status were assessed by questionnaire for the occupation stress and self-rating symptom. The people with mental disorder was 556, the incidence rate was40. 29%. The level of occupational stress level low-high group( RR = 2. 689, 95% CI1. 342-5. 391) and middle-high group( RR = 2. 878, 95% CI 1. 205-6. 875) of mental disorder were higher than the low-low group, the level of Personal Strain Questionnaire low-middle group( RR = 2. 500, 95% CI 1. 700-3. 763) and low-high group( RR =3. 907, 95% CI 1. 955-7. 651) and middle-middle group( RR = 2. 141, 95% CI 1. 016-4. 512) of mental disorder were higher than low-low group. Without drinking( RR =0. 779, 95% CI = 0. 622-0. 976) was protective factor for mental disorders. Occupational stress and drinking are the risk factors of mental disorder, it is more practical to multiple measurement of the psychological disorder of occupational stress exposure than single one.

Refining the multisystem view of the stress response: coordination among cortisol, alpha-amylase, and subjective stress in response to relationship conflict.

PubMed

Laurent, Heidemarie K; Powers, Sally I; Granger, Douglas A

2013-07-02

This study investigated associations among young adults' hypothalamic-pituitary-adrenal axis activity, autonomic nervous system activity, and subjective stress in response to interpersonal conflict to better characterize coordination across stress systems. Seven saliva samples were collected from 199 young adult opposite-sex couples before, during, and after they discussed an unresolved relationship conflict. Samples were later assayed for cortisol and alpha-amylase (sAA). Couples rated anticipatory stress prior to the conflict and perceived stress immediately following the task. Growth curve modeling was used to examine two possible levels of within-person coordination across physiological systems: alignment between cortisol and sAA responses throughout the sampling period ("matched phase coordination"), and association between overall levels of cortisol and sAA in response to conflict ("average level coordination"). Whereas both partners showed the former type of coordination, only women showed the latter type. Positive anticipation of the stressor predicted stronger cortisol-sAA matched phase coordination for women. Pre-task ratings related to women's sAA, and post-task ratings related to both partners' cortisol responses. Implications for a multisystem interpretation of normal and pathological responses to daily stress are discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

Stress influenced trapping processes in Si based multi-quantum well structures and heavy ions implanted Si

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciurea, Magdalena Lidia, E-mail: ciurea@infim.ro; Lazanu, Sorina, E-mail: ciurea@infim.ro

2014-10-06

Multi-quantum well structures and Si wafers implanted with heavy iodine and bismuth ions are studied in order to evaluate the influence of stress on the parameters of trapping centers. The experimental method of thermostimullatedcurrents without applied bias is used, and the trapping centers are filled by illumination. By modeling the discharge curves, we found in multilayered structures the parameters of both 'normal' traps and 'stress-induced' ones, the last having a Gaussian-shaped temperature dependence of the cross section. The stress field due to the presence of stopped heavy ions implanted into Si was modeled by a permanent electric field. The increasemore » of the strain from the neighborhood of I ions to the neighborhood of Bi ions produces the broadening of some energy levels and also a temperature dependence of the cross sections for all levels.« less

Stress influenced trapping processes in Si based multi-quantum well structures and heavy ions implanted Si

NASA Astrophysics Data System (ADS)

Ciurea, Magdalena Lidia; Lazanu, Sorina

2014-10-01

Multi-quantum well structures and Si wafers implanted with heavy iodine and bismuth ions are studied in order to evaluate the influence of stress on the parameters of trapping centers. The experimental method of thermostimullatedcurrents without applied bias is used, and the trapping centers are filled by illumination. By modeling the discharge curves, we found in multilayered structures the parameters of both 'normal' traps and 'stress-induced' ones, the last having a Gaussian-shaped temperature dependence of the cross section. The stress field due to the presence of stopped heavy ions implanted into Si was modeled by a permanent electric field. The increase of the strain from the neighborhood of I ions to the neighborhood of Bi ions produces the broadening of some energy levels and also a temperature dependence of the cross sections for all levels.

Obesity-Associated Oxidative Stress: Strategies Finalized to Improve Redox State

PubMed Central

Savini, Isabella; Catani, Maria Valeria; Evangelista, Daniela; Gasperi, Valeria; Avigliano, Luciana

2013-01-01

Obesity represents a major risk factor for a plethora of severe diseases, including diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and cancer. It is often accompanied by an increased risk of mortality and, in the case of non-fatal health problems, the quality of life is impaired because of associated conditions, including sleep apnea, respiratory problems, osteoarthritis, and infertility. Recent evidence suggests that oxidative stress may be the mechanistic link between obesity and related complications. In obese patients, antioxidant defenses are lower than normal weight counterparts and their levels inversely correlate with central adiposity; obesity is also characterized by enhanced levels of reactive oxygen or nitrogen species. Inadequacy of antioxidant defenses probably relies on different factors: obese individuals may have a lower intake of antioxidant- and phytochemical-rich foods, such as fruits, vegetables, and legumes; otherwise, consumption of antioxidant nutrients is normal, but obese individuals may have an increased utilization of these molecules, likewise to that reported in diabetic patients and smokers. Also inadequate physical activity may account for a decreased antioxidant state. In this review, we describe current concepts in the meaning of obesity as a state of chronic oxidative stress and the potential interventions to improve redox balance. PMID:23698776

Traction force microscopy of engineered cardiac tissues.

PubMed

Pasqualini, Francesco Silvio; Agarwal, Ashutosh; O'Connor, Blakely Bussie; Liu, Qihan; Sheehy, Sean P; Parker, Kevin Kit

2018-01-01

Cardiac tissue development and pathology have been shown to depend sensitively on microenvironmental mechanical factors, such as extracellular matrix stiffness, in both in vivo and in vitro systems. We present a novel quantitative approach to assess cardiac structure and function by extending the classical traction force microscopy technique to tissue-level preparations. Using this system, we investigated the relationship between contractile proficiency and metabolism in neonate rat ventricular myocytes (NRVM) cultured on gels with stiffness mimicking soft immature (1 kPa), normal healthy (13 kPa), and stiff diseased (90 kPa) cardiac microenvironments. We found that tissues engineered on the softest gels generated the least amount of stress and had the smallest work output. Conversely, cardiomyocytes in tissues engineered on healthy- and disease-mimicking gels generated significantly higher stresses, with the maximal contractile work measured in NRVM engineered on gels of normal stiffness. Interestingly, although tissues on soft gels exhibited poor stress generation and work production, their basal metabolic respiration rate was significantly more elevated than in other groups, suggesting a highly ineffective coupling between energy production and contractile work output. Our novel platform can thus be utilized to quantitatively assess the mechanotransduction pathways that initiate tissue-level structural and functional remodeling in response to substrate stiffness.

Mangifera indica L. leaf extract alleviates doxorubicin induced cardiac stress

PubMed Central

Bhatt, Laxit; Joshi, Viraj

2017-01-01

Aim: The study was undertaken to evaluate the cardioprotective effect of the alcoholic leaf extract of Mangifera indica L. against cardiac stress caused by doxorubicin (DOX). Materials and Methods: Rats were treated with 100 mg/kg of M. indica leaf extract (MILE) in alone and interactive groups for 21 days. Apart from the normal and MILE control groups, all the groups were subjected to DOX (15 mg/kg, i.p.) toxicity for 21 days and effects of different treatments were analyzed by changes in serum biomarkers, tissue antioxidant levels, electrocardiographic parameters, lipid profile, and histopathological evaluation. Results: The MILE treated group showed decrease in serum biomarker enzyme levels and increase in tissue antioxidants levels. Compared to DOX control group, MILE treated animals showed improvement in lipid profile, electrocardiographic parameters, histological score, and mortality. Conclusion: These findings clearly suggest the protective role of alcoholic leaf extract of M. indica against oxidative stress induced by DOX. PMID:28894627

Concrete with onyx waste aggregate as aesthetically valued structural concrete

NASA Astrophysics Data System (ADS)

Setyowati E., W.; Soehardjono, A.; Wisnumurti

2017-09-01

The utillization of Tulungagung onyx stone waste as an aggregate of concrete mixture will improve the economic value of the concrete due to the brighter color and high aesthetic level of the products. We conducted the research of 75 samples as a test objects to measure the compression stress, splits tensile stress, flexural tensile stress, elasticity modulus, porosity modulus and also studied 15 test objects to identify the concrete micro structures using XRD test, EDAX test and SEM test. The test objects were made from mix designed concrete, having ratio cement : fine aggregate : coarse aggregate ratio = 1 : 1.5 : 2.1, and W/C ratio = 0.4. The 28 days examination results showed that the micro structure of Tulungagung onyx waste concrete is similar with normal concrete. Moreover, the mechanical test results proved that Tulungagung onyx waste concretes also have a qualified level of strength to be used as a structural concrete with higher aesthetic level.

Oxidative stress and apoptosis in preeclampsia.

PubMed

Can, Murat; Guven, Berrak; Bektas, Sibel; Arikan, Ilker

2014-12-01

We aimed to determine the oxidative stress and antioxidant status in preeclamptic placenta. Also, we investigated the apoptotic index of villous trophoblast and proliferation index of cytotrophoblasts. The study included 32 pregnant with preeclampsia and 31 normotensive healthy pregnant women. Malondialdehyde (MDA) and total antioxidant status (TAS) levels were measured in the placenta. For detection of apoptosis and proliferation in trophoblast, apoptosis protease activating factor 1 (APAF-1) and Ki-67 were used. Placental MDA levels in preeclamptic women were significantly higher than normal pregnancies (p=0.002). There was no significant difference between the groups in the TAS levels of placenta (p=0.773). Also, the apoptotic index in villous trophoblasts increased (p<0.001), but proliferation index did not change in preeclampsia (p=0.850). Increased oxidative stress and apoptosis in pathological placenta are not balanced by antioxidant systems and proliferation mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Detection of Redox Imbalance in Normal Lymphocytes with Induced Mitochondrial Dysfunction - EPR Study.

PubMed

Georgieva, Ekaterina; Zhelev, Zhivko; Aoki, Ichio; Bakalova, Rumiana; Higashi, Tatsuya

2016-10-01

The present study describes a new approach for direct imaging of redox status in live cells using paramagnetic spin-probes, which allows evaluation of the level of oxidative stress due to overproduction of superoxide. The method is based on redox cycling of cell/mitochondria-penetrating nitroxide radicals (e.g. mito-TEMPO) and their electron-paramagnetic resonance (EPR) contrast, which makes them useful molecular sensors for analysis of redox status and oxidative stress in cells and tissues. Oxidative stress was induced in normal human lymphocytes by treatment with 2-methoxyestradiol and rotenone (ME/Rot) at different concentrations. This combination provokes mitochondrial dysfunction, which is accompanied by overproduction of superoxide. The EPR measurements were performed in dynamics on X-Band spectrometer after addition of mito-TEMPO to cell suspensions. The intensity of the EPR signal in untreated cells decreased significantly, which indicates a conversion of paramagnetic mito-TEMPO to its non-contrast diamagnetic form (hydroxylamine - mito-TEMPOH) due to reduction. In ME/Rot-treated cells, the signal decreased more slowly and to a lower level with increasing the concentration of ME/Rot. These data indicate an induction of oxidative stress in the cells in a concentration-dependent manner. A very good positive correlation between the intensity of EPR signal of mito-TEMPO and the intracellular level of superoxide was found, analyzed by conventional dihydroethidium test (R=0.9143, p<0.001). In conclusion, our study demonstrated that cell-penetrating paramagnetic spin-probes, such as mito-TEMPO, are valuable tools for EPR imaging of the superoxide level in live cells, as well as for EPR imaging of mitochondrial dysfunction and metabolic activity, accompanied by superoxide imbalance. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

The hepatocurative effects of Cynara scolymus L. leaf extract on carbon tetrachloride-induced oxidative stress and hepatic injury in rats.

PubMed

Colak, Emine; Ustuner, Mehmet Cengiz; Tekin, Neslihan; Colak, Ertugrul; Burukoglu, Dilek; Degirmenci, Irfan; Gunes, Hasan Veysi

2016-01-01

Cynara scolymus is a pharmacologically important medicinal plant containing phenolic acids and flavonoids. Experimental studies indicate antioxidant and hepatoprotective effects of C. scolymus but there have been no studies about therapeutic effects of liver diseases yet. In the present study, hepatocurative effects of C. scolymus leaf extract on carbon tetrachloride (CCl4)-induced oxidative stress and hepatic injury in rats were investigated by serum hepatic enzyme levels, oxidative stress indicator (malondialdehyde-MDA), endogenous antioxidants, DNA fragmentation, p53, caspase 3 and histopathology. Animals were divided into six groups: control, olive oil, CCl4, C. scolymus leaf extract, recovery and curative. CCl4 was administered at a dose of 0.2 mL/kg twice daily on CCl4, recovery and curative groups. Cynara scolymus extract was given orally for 2 weeks at a dose of 1.5 g/kg after CCl4 application on the curative group. Significant decrease of serum alanine-aminotransferase (ALT) and aspartate-aminotransferase (AST) levels were determined in the curative group. MDA levels were significantly lower in the curative group. Significant increase of superoxide dismutase (SOD) and catalase (CAT) activity in the curative group was determined. In the curative group, C. scolymus leaf extract application caused the DNA % fragmentation, p53 and caspase 3 levels of liver tissues towards the normal range. Our results indicated that C. scolymus leaf extract has hepatocurative effects of on CCl4-induced oxidative stress and hepatic injury by reducing lipid peroxidation, providing affected antioxidant systems towards the normal range. It also had positive effects on the pathway of the regulatory mechanism allowing repair of DNA damage on CCl4-induced hepatotoxicity.

ROLE OF NRF2 IN THE OXIDATIVE STRESS-DEPENDENT HYPERTENSION ASSOCIATED WITH THE DEPLETION OF DJ-1

PubMed Central

Cuevas, Santiago; Yang, Yu; Konkalmatt, Prasad; Asico, Laureano; Feranil, Jun; Jones, John; Villar, Van Anthony; Armando, Ines; Jose, Pedro A.

2015-01-01

Renal dopamine 2 receptor dysfunction is associated with oxidative stress and high blood pressure. We have reported that DJ-1, an oxidative stress response protein, is positively regulated by dopamine 2 receptor in the kidney. The transcription factor Nrf2 regulates the expression of several antioxidant genes. We tested the hypothesis that Nrf2 is involved in the renal DJ-1-mediated inhibition of reactive oxygen species production. We have reported that silencing dopamine 2 receptor in mouse renal proximal tubule cells decreases the expression of DJ-1. We now report that silencing DJ-1 or dopamine 2 receptor in mouse proximal tubule cells and mouse kidneys, decreases Nrf2 expression and activity and increases reactive oxygen species production; blood pressure is also increased in mice in which renal DJ-1 or dopamine 2 receptor is silenced. DJ-1−/− mice have decreased renal Nrf2 expression and activity, and increased nitro-tyrosine levels an dopamine 2 receptor d blood pressure. Silencing Nrf2 in mouse proximal tubule cells does not alter the expression of DJ-1 or dopamine 2 receptor, indicating that Nrf2 is downstream of dopamine 2 receptor and DJ-1. A Nrf2 inducer, bardoxolone, normalizes the systolic blood pressure and renal malondialdehyde levels in DJ-1−/− mice without affecting them in their wild-type littermates. Because Nrf2 ubiquitination is increased in DJ-1−/− mice, we conclude that the protective effect of DJ-1 on renal oxidative stress is mediated, in part, by preventing Nrf2 degradation. Moreover, renal dopamine 2 receptor and DJ-1 are necessary for normal Nrf2 activity to keep a normal redox balance and blood pressure. PMID:25895590

Oxidative stress biomarkers and their relationship with cytokine concentrations in overweight/obese pregnant women and their neonates.

PubMed

Hernández-Trejo, María; Montoya-Estrada, Araceli; Torres-Ramos, Yessica; Espejel-Núñez, Aurora; Guzmán-Grenfell, Alberto; Morales-Hernández, Rosa; Tolentino-Dolores, Maricruz; Laresgoiti-Servitje, Estibalitz

2017-01-07

Oxidative damage present in obese/overweight mothers may lead to further oxidative stress conditions or inflammation in maternal and cord blood samples. Thirty-four pregnant women/newborn pairs were included in this study to assess the presence of oxidative stress biomarkers and their relationship with serum cytokine concentrations. Oxidative stress biomarkers and antioxidant enzymes were compared between the mother/offspring pairs. The presence of 27 cytokines was measured in maternal and cord blood samples. Analyses were initially performed between all mothers and newborns and later between normal weight and mothers with overweight and obesity, and diabetic/non-diabetic women. Significant differences were found in biomarker concentrations between mothers and newborns. Additionally, superoxide-dismutase activity was higher in pre-pregnancy overweight mothers compared to those with normal weight. Activity for this enzyme was higher in neonates born from mothers with normal pregestational weight compared with their mothers. Nitrites in overweight/obese mothers were statistically lower than in their offspring. Maternal free fatty acids, nitrites, carbonylated proteins, malondialdehyde and superoxide dismutase predicted maternal serum concentrations of IL-4, IL-13, IP-10 and MIP-1β. Arginase activity in maternal plasma was related to decreased concentrations of IL-4 and IL-1β in cord arterial blood. Increased maternal malondialdehyde plasma was associated with higher levels of IL-6 and IL-7 in the offspring. Oxidative stress biomarkers differ between mothers and offspring and can predict maternal and newborn cytokine concentrations, indicating a potential role for oxidative stress in foetal metabolic and immunologic programming. Moreover, maternal obesity and diabetes may affect maternal microenvironments, and oxidative stress related to these can have an impact on the placenta and foetal growth.

Nonlinear interaction of strong S-waves with the rupture front in the shallow subsurface

NASA Astrophysics Data System (ADS)

Sleep, N. H.

2017-12-01

Shallow deformation in moderate to large earthquakes is sometimes distributed rather than being concentrated on a single fault plane. Strong high-frequency S-waves interact with the rupture front to produce this effect. For strike-slip faults, the rupture propagation velocity is a fraction of the S-wave velocity. The rupture propagation vector refracts essentially vertically in the low (S-wave) velocity shallow subsurface. So does the propagation direction of S-waves. The shallow rupture front is essentially mode 3 near the surface. Strong S-waves arrive before the rupture front. They continue to arrive for several seconds in a large event. There are simple scaling relationships. The dynamic Coulomb stress ratio of horizontal stress on horizontal planes from S-waves is the normalized acceleration in g's. For fractured rock and gravel, frictional failure occurs when the normalized acceleration exceeds the effective coefficient of friction. Acceleration tends to saturate at that level as the anelastic strain rate increases rapidly with stress. For muddy materials, failure begins at a low normalized acceleration but increases slowly with dynamic stress. Dynamic accelerations sometimes exceed 1 g. In both cases, the rupture tip finds the shallow subsurface already in nonlinear failure down to a few to tens of meters depth. The material does not distinguish between S-wave and rupture tip stresses. Both stresses add to the stress invariant and hence to the anelastic strain rate tensor. Surface anelastic strain from fault slip is thus distributed laterally over a distance scaling to the depth of nonlinearity from S-waves. The environs of the fault anelastically accommodate the fault slip at depth. This process differs from blind faults where the shallow coseismic strain is mostly elastic and interseismic anelastic processes accommodate the long-term shallow deformation.

Iodinated contrast media can induce long-lasting oxidative stress in hemodialysis patients.

PubMed

Hwang, Seun Deuk; Kim, Yoon Ji; Lee, Sang Heun; Cho, Deok Kyu; Cho, Yun Hyeong; Moon, Sung Jin; Lee, Sang Choel; Yoon, Soo Young

2013-11-01

Due to their comorbidities, dialysis patients have many chances to undergo radiologic procedures using iodinated contrast media. We aimed to assess time-sequenced blood oxidative stress level after contrast exposure in hemodialysis (HD) patients compared to those in the non-dialysis population. We included 21 anuric HD patients [HD-coronary angiography (CAG) group] and 23 persons with normal renal function (nonHD-CAG group) scheduled for CAG, and assessed 4 oxidative stress markers [advanced oxidation protein products (AOPP); catalase; 8-hydroxydeoxyguanosine; and malondialdehyde] before and after CAG, and subsequently up to 28 days. In the nonHD-CAG group, only AOPP increased immediately after CAG and returned to baseline within one day. However, in the HD-CAG group, all four oxidative stress markers were significantly increased starting one day after CAG, and remained elevated longer than those in the nonHD-CAG group. Especially, AOPP level remained elevated for a month after contrast exposure. Our study showed that iodinated contrast media induces severe and prolonged oxidative stress in HD patients.

Flux-pinning-induced interfacial shearing and transverse normal stress in a superconducting coated conductor long strip

NASA Astrophysics Data System (ADS)

Jing, Ze; Yong, Huadong; Zhou, Youhe

2012-08-01

In this paper, a theoretical model is proposed to analyze the transverse normal stress and interfacial shearing stress induced by the electromagnetic force in the superconducting coated conductor. The plane strain approach is used and a singular integral equation is derived. By assuming that the critical current density is magnetic field independent and the superconducting film is infinitely thin, the interfacial shearing stress and normal stress in the film are evaluated for the coated conductor during the increasing and decreasing in the transport current, respectively. The calculation results are discussed and compared for the conductor with different substrate and geometry. The results indicate that the coated conductor with stiffer substrate and larger width experiences larger interfacial shearing stress and less normal stress in the film.

Normal stresses in shear thickening granular suspensions.

PubMed

Pan, Zhongcheng; de Cagny, Henri; Habibi, Mehdi; Bonn, Daniel

2017-05-24

When subjected to shear, granular suspensions exhibit normal stresses perpendicular to the shear plane but the magnitude and sign of the different components of the normal stresses are still under debate. By performing both oscillatory and rotational rheology measurements on shear thickening granular suspensions and systematically varying the particle diameters and the gap sizes between two parallel-plates, we show that a transition from a positive to a negative normal stress can be observed. We find that frictional interactions which determine the shear thickening behavior of suspensions contribute to the positive normal stresses. Increasing the particle diameters or decreasing the gap sizes leads to a growing importance of hydrodynamic interactions, which results in negative normal stresses. We determine a relaxation time for the system, set by both the pore and the gap sizes, that governs the fluid flow through the inter-particle space. Finally, using a two-fluid model we determine the relative contributions from the particle phase and the liquid phase.

One-pot three-component synthesis of novel heterocyclic steroids as a central antioxidant and anti-inflammatory agents.

PubMed

Mohamed, Nadia R; Abdelhalim, Mervat M; Khadrawy, Yasser A; Elmegeed, Gamal A; Abdel-Salam, Omar M E

2012-11-01

Oxidative stress and inflammation have been implicated in several neurodegenerative and developmental brain disorders. The present work was devoted to the design and synthesis of novel steroid derivatives bearing promising heterocyclic moiety that would act to reduce neuro-inflammation and oxidative stress in brain. The novel heterocyclic steroids were synthesized and their chemical structures were confirmed by studying their analytical and spectral data. The tested compounds were assayed in the model of neuro-inflammation produced in rats by cerebral lipopolysaccharide injection. The intracerebral administration of bacterial endotoxin resulted in cerebral inflammatory state evidenced by increased malondialdehyde (MDA), decreased reduced glutathione (GSH) level, increased nitric oxide as well as increased acetylcholinesterase (AChE) activity in the brain. Compounds 6, 10, 8b and 13a markedly increased reduced glutathione. Malondialadehyde and nitric oxide levels were reduced to normal values after treatment with all tested compounds. AChE activity was normalized by compound 8b and reduced to below normal values by compounds 10 and 14a. These results are exciting in that these agents might be useful candidates in treatment of cerebral inflammation. Copyright © 2012 Elsevier Inc. All rights reserved.

D1 Receptors Regulate Dendritic Morphology in Normal and Stressed Prelimbic Cortex

PubMed Central

Lin, Grant L.; Borders, Candace B.; Lundewall, Leslie J.; Wellman, Cara L.

2014-01-01

Both stress and dysfunction of prefrontal cortex are linked to psychological disorders, and structure and function of medial prefrontal cortex (mPFC) are altered by stress. Chronic restraint stress causes dendritic retraction in the prelimbic region (PL) of mPFC in rats. Dopamine release in mPFC increases during stress, and chronic administration of dopaminergic agonists results in dendritic remodeling. Thus, stress-induced alterations in dopaminergic transmission in PL may contribute to dendritic remodeling. We examined the effects of dopamine D1 receptor (D1R) blockade in PL during daily restraint stress on dendritic morphology in PL. Rats either underwent daily restraint stress (3 h/day, 10 days) or remained unstressed. In each group, rats received daily infusions of either the D1R antagonist SCH23390 or vehicle into PL prior to restraint; unstressed and stressed rats that had not undergone surgery were also examined. On the final day of restraint, rats were euthanized and brains were processed for Golgi histology. Pyramidal neurons in PL were reconstructed and dendritic morphology was quantified. Vehicle-infused stressed rats demonstrated dendritic retraction compared to unstressed rats, and D1R blockade in PL prevented this effect. Moreover, in unstressed rats, D1R blockade produced dendritic retraction. These effects were not due to attenuation of the HPA axis response to acute stress: plasma corticosterone levels in a separate group of rats that underwent acute restraint stress with or without D1R blockade were not significantly different. These findings indicate that dopaminergic transmission in mPFC during stress contributes directly to the stress-induced retraction of apical dendrites, while dopamine transmission in the absence of stress is important in maintaining normal dendritic morphology. PMID:25305546

D1 receptors regulate dendritic morphology in normal and stressed prelimbic cortex.

PubMed

Lin, Grant L; Borders, Candace B; Lundewall, Leslie J; Wellman, Cara L

2015-01-01

Both stress and dysfunction of prefrontal cortex are linked to psychological disorders, and structure and function of medial prefrontal cortex (mPFC) are altered by stress. Chronic restraint stress causes dendritic retraction in the prelimbic region (PL) of mPFC in rats. Dopamine release in mPFC increases during stress, and chronic administration of dopaminergic agonists results in dendritic remodeling. Thus, stress-induced alterations in dopaminergic transmission in PL may contribute to dendritic remodeling. We examined the effects of dopamine D1 receptor (D1R) blockade in PL during daily restraint stress on dendritic morphology in PL. Rats either underwent daily restraint stress (3h/day, 10 days) or remained unstressed. In each group, rats received daily infusions of either the D1R antagonist SCH23390 or vehicle into PL prior to restraint; unstressed and stressed rats that had not undergone surgery were also examined. On the final day of restraint, rats were euthanized and brains were processed for Golgi histology. Pyramidal neurons in PL were reconstructed and dendritic morphology was quantified. Vehicle-infused stressed rats demonstrated dendritic retraction compared to unstressed rats, and D1R blockade in PL prevented this effect. Moreover, in unstressed rats, D1R blockade produced dendritic retraction. These effects were not due to attenuation of the HPA axis response to acute stress: plasma corticosterone levels in a separate group of rats that underwent acute restraint stress with or without D1R blockade were not significantly different. These findings indicate that dopaminergic transmission in mPFC during stress contributes directly to the stress-induced retraction of apical dendrites, while dopamine transmission in the absence of stress is important in maintaining normal dendritic morphology. Copyright © 2014 Elsevier Ltd. All rights reserved.

[OPEN FIELD BEHAVIOR AS A PREDICTIVE CRITERIA REFLECTING RATS CORTICOSTERONELEVEL BEFORE AND AFTER STRESS].

PubMed

Umriukhin, P E; Grigorchuk, O S

2015-12-01

In the presented study we investigated the possibility to use the open field behavior data for prediction of corticosterone level in rat blood plasma before and after stress. It is shown that the most reliable open field behavior parameters, reflecting high probability of significant upregulation of corticosterone after 3 hours of immobilization, are the short latency of first movement and low locomotor activity during the test. Rats with high corticosterone at normal non-stress conditions are characterized by low locomotor activity and on the contrary long latency period for the entrance of open field center.

Stress and the HPA Axis

PubMed Central

Stephens, Mary Ann C.; Wand, Gary

2012-01-01

Stress has long been suggested to be an important correlate of uncontrolled drinking and relapse. An important hormonal response system to stress—the hypothalamic–pituitary–adrenal (HPA) axis—may be involved in this process, particularly stress hormones known as glucocorticoids and primarily cortisol. The actions of this hormone system normally are tightly regulated to ensure that the body can respond quickly to stressful events and return to a normal state just as rapidly. The main determinants of HPA axis activity are genetic background, early-life environment, and current life stress. Alterations in HPA axis regulation are associated with problematic alcohol use and dependence; however, the nature of this dysregulation appears to vary with respect to stage of alcohol dependence. Much of this research has focused specifically on the role of cortisol in the risk for, development of, and relapse to chronic alcohol use. These studies found that cortisol can interact with the brain’s reward system, which may contribute to alcohol’s reinforcing effects. Cortisol also can influence a person’s cognitive processes, promoting habit-based learning, which may contribute to habit formation and risk of relapse. Finally, cortisol levels during abstinence may be useful clinical indicators of relapse vulnerability in alcohol-dependent people. PMID:23584113

Anti-Apoptotic Protein Bcl-xL Expression in the Midbrain Raphe Region Is Sensitive to Stress and Glucocorticoids.

PubMed

Shishkina, Galina T; Kalinina, Tatyana S; Bulygina, Veta V; Lanshakov, Dmitry A; Babluk, Ekaterina V; Dygalo, Nikolay N

2015-01-01

Anti-apoptotic proteins are suggested to be important for the normal health of neurons and synapses as well as for resilience to stress. In order to determine whether stressful events may influence the expression of anti-apoptotic protein Bcl-xL in the midbrain and specifically in the midbrain serotonergic (5-HT) neurons involved in neurobehavioral responses to adverse stimuli, adult male rats were subjected to short-term or chronic forced swim stress. A short-term stress rapidly increased the midbrain bcl-xl mRNA levels and significantly elevated Bcl-xL immunoreactivity in the midbrain 5-HT cells. Stress-induced increase in glucocorticoid secretion was implicated in the observed effect. The levels of bcl-xl mRNA were decreased after stress when glucocorticoid elevation was inhibited by metyrapone (MET, 150 mg/kg), and this decrease was attenuated by glucocorticoid replacement with dexamethasone (DEX; 0.2 mg/kg). Both short-term stress and acute DEX administration, in parallel with Bcl-xL, caused a significant increase in tph2 mRNA levels and slightly enhanced tryptophan hydroxylase immunoreactivity in the midbrain. The increasing effect on the bcl-xl expression was specific to the short-term stress. Forced swim repeated daily for 2 weeks led to a decrease in bcl-xl mRNA in the midbrain without any effects on the Bcl-xL protein expression in the 5-HT neurons. In chronically stressed animals, an increase in tph2 gene expression was not associated with any changes in tryptophan hydroxylase protein levels. Our findings are the first to demonstrate that both short-term stress and acute glucocorticoid exposures induce Bcl-xL protein expression in the midbrain 5-HT neurons concomitantly with the activation of the 5-HT synthesis pathway in these neurons.

46 CFR Appendix B to Part 154 - Stress Analyses Definitions

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

46 CFR Appendix B to Part 154 - Stress Analyses Definitions

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

46 CFR Appendix B to Part 154 - Stress Analyses Definitions

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

46 CFR Appendix B to Part 154 - Stress Analyses Definitions

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

46 CFR Appendix B to Part 154 - Stress Analyses Definitions

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

Sleep deprivation predisposes liver to oxidative stress and phospholipid damage: a quantitative molecular imaging study

PubMed Central

Chang, Hung-Ming; Mai, Fu-Der; Chen, Bo-Jung; Wu, Un-In; Huang, Yi-Lun; Lan, Chyn-Tair; Ling, Yong-Chien

2008-01-01

Sleep disorders are associated with an increased rate of various metabolic disturbances, which may be related to oxidative stress and consequent lipid peroxidation. Since hepatic phosphatidylcholine plays an important role in metabolic regulation, the aim of the present study was to determine phosphatidylcholine expression in the liver following total sleep deprivation. To determine the effects of total sleep deprivation, we used adult rats implanted for polygraphic recording. Phosphatidylcholine expression was examined molecularly by the use of time-of-flight secondary ion mass spectrometry, along with biochemical solid-phase extraction. The parameters of oxidative stress were investigated by evaluating the hepatic malondialdehyde levels as well as heat shock protein 25 immunoblotting and immunohistochemistry. In normal rats, the time-of-flight secondary ion mass spectrometry spectra revealed specific peaks (m/z 184 and 224) that could be identified as molecular ions for phosphatidylcholine. However, following total sleep deprivation, the signals for phosphatidylcholine were significantly reduced to nearly one-third of the normal values. The results of solid-phase extraction also revealed that the phosphatidylcholine concentration was noticeably decreased, from 15.7 µmol g–1 to 9.4 µmol g–1, after total sleep deprivation. By contrast, the biomarkers for oxidative stress were drastically up-regulated in the total sleep deprivation-treated rats as compared with the normal ones (4.03 vs. 1.58 nmol mg–1 for malondialdehyde levels, and 17.1 vs. 6.7 as well as 1.8 vs. 0.7 for heat shock protein 25 immunoblotting and immunoreactivity, respectively). Given that phosphatidylcholine is the most prominent component of all plasma lipoproteins, decreased expression of hepatic phosphatidylcholine following total sleep deprivation may be attributed to the enhanced oxidative stress and the subsequent lipid peroxidation, which would play an important role in the formation or progression of total sleep deprivation-induced metabolic diseases. PMID:18221481

Exposure to excess insulin (glargine) induces type 2 diabetes mellitus in mice fed on a chow diet.

PubMed

Yang, Xuefeng; Mei, Shuang; Gu, Haihua; Guo, Huailan; Zha, Longying; Cai, Junwei; Li, Xuefeng; Liu, Zhenqi; Cao, Wenhong

2014-06-01

We have previously shown that insulin plays an important role in the nutrient-induced insulin resistance. In this study, we tested the hypothesis that chronic exposure to excess long-acting insulin (glargine) can cause typical type 2 diabetes mellitus (T2DM) in normal mice fed on a chow diet. C57BL/6 mice were treated with glargine once a day for 8 weeks, followed by evaluations of food intake, body weight, blood levels of glucose, insulin, lipids, and cytokines, insulin signaling, histology of pancreas, ectopic fat accumulation, oxidative stress level, and cholesterol content in mitochondria in tissues. Cholesterol content in mitochondria and its association with oxidative stress in cultured hepatocytes and β-cells were also examined. Results show that chronic exposure to glargine caused insulin resistance, hyperinsulinemia, and relative insulin deficiency (T2DM). Treatment with excess glargine led to loss of pancreatic islets, ectopic fat accumulation in liver, oxidative stress in liver and pancreas, and increased cholesterol content in mitochondria of liver and pancreas. Prolonged exposure of cultured primary hepatocytes and HIT-TI5 β-cells to insulin induced oxidative stress in a cholesterol synthesis-dependent manner. Together, our results show that chronic exposure to excess insulin can induce typical T2DM in normal mice fed on a chow diet. © 2014 The authors.

Toxicological and pharmacological concerns on oxidative stress and related diseases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saeidnia, Soodabeh; College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon; Abdollahi, Mohammad, E-mail: Mohammad@TUMS.Ac.Ir

2013-12-15

Although reactive oxygen species (ROS) such as superoxide, hydrogen peroxide and hydroxyl radical are generated as the natural byproduct of normal oxygen metabolism, they can create oxidative damage via interaction with bio-molecules. The role of oxidative stress as a remarkable upstream part is frequently reported in the signaling cascade of inflammation as well as chemo attractant production. Even though hydrogen peroxide can control cell signaling and stimulate cell proliferation at low levels, in higher concentrations it can initiate apoptosis and in very high levels may create necrosis. So far, the role of ROS in cellular damage and death is wellmore » documented with implicating in a broad range of degenerative alterations e.g. carcinogenesis, aging and other oxidative stress related diseases (OSRDs). Reversely, it is cleared that antioxidants are potentially able to suppress (at least in part) the immune system and to enhance the normal cellular protective responses to tissue damage. In this review, we aimed to provide insights on diverse OSRDs, which are correlated with the concept of oxidative stress as well as its cellular effects that can be inhibited by antioxidants. Resveratrol, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, statins, nebivolol and carvedilol, pentaerythritol tetranitrate, mitochondria-targeted antioxidants, and plant-derived drugs (alone or combined) are the potential medicines that can be used to control OSRD.« less

Long-term treatment of hydrogen-rich saline abates testicular oxidative stress induced by nicotine in mice.

PubMed

Li, Shu; Lu, DanDan; Zhang, Yaling; Zhang, Yi

2014-01-01

The present study was designed to test the hypothesis that long-term treatment with hydrogen-rich saline abated testicular oxidative stress induced by nicotine in mice. The effects of hydrogen-rich saline (6 ml/kg, i.p.), vitamin C (60 mg/kg, i.p.) and vitamin E (100 mg/kg, i.p.) on reproductive system and testicular oxidative levels in nicotine-treated (4.5 mg/kg, s.b.) mice were investigated. It was found that vitamin C and vitamin E attenuated serum oxidative level, but did not lower testicular oxidative levels in mice subjected to chronic nicotine treatment, and did not improve the male reproductive damage and apoptosis induced by nicotine. Different from normal antioxidants, vitamin C and vitamin E, hydrogen-rich saline abated oxidative stress in testis, and protected against nicotine-induced male reproductive damages. Our results first demonstrated that long-term treatment with hydrogen-rich saline attenuated testicular oxidative level and improved male reproductive function in nicotine-treated mice.

Project ES3: attempting to quantify and measure the level of stress.

PubMed

Aguiló, Jordi; Ferrer-Salvans, Pau; García-Rozo, Antonio; Armario, Antonio; Corbí, Ángel; Cambra, Francisco J; Bailón, Raquel; González-Marcos, Ana; Caja, Gerardo; Aguiló, Sira; López-Antón, Raúl; Arza-Valdés, Adriana; Garzón-Rey, Jorge M

2015-11-01

The WHO has qualified stress as a 'world epidemic' due to its increasingly greater incidence on health. The work described in this paper represents an attempt to objectively quantify the level of stress. The aim of the method developed here is to measure how close or how far a subject is from a situation that can be considered 'normal' in medical and social terms. The literature on the pathophysiology of stress and its methods of study in experiments on both animals and humans was reviewed. Nine prospective observational studies were undertaken with different types of subjects and stressors covering the different types of stress. The results of the literature review made it possible to identify the different types of stress, the indicators that yield significant results, the psychometric tests and the well-documented 'stressors'. This material was then used to design the general method and the details of the nine clinical trials. The preliminary results obtained in some of the studies were used to validate the indicators as well as the efficacy of the techniques used experimentally to diminish stress or to produce it. The early results obtained in the experimental trials show that we are on the right path towards defining and validating multivariable markers for quantifying levels of stress and also suggest that the method can be applied in a similar way to the study of mental disorders.

Fluid involvement in normal faulting

NASA Astrophysics Data System (ADS)

Sibson, Richard H.

2000-04-01

Evidence of fluid interaction with normal faults comes from their varied role as flow barriers or conduits in hydrocarbon basins and as hosting structures for hydrothermal mineralisation, and from fault-rock assemblages in exhumed footwalls of steep active normal faults and metamorphic core complexes. These last suggest involvement of predominantly aqueous fluids over a broad depth range, with implications for fault shear resistance and the mechanics of normal fault reactivation. A general downwards progression in fault rock assemblages (high-level breccia-gouge (often clay-rich) → cataclasites → phyllonites → mylonite → mylonitic gneiss with the onset of greenschist phyllonites occurring near the base of the seismogenic crust) is inferred for normal fault zones developed in quartzo-feldspathic continental crust. Fluid inclusion studies in hydrothermal veining from some footwall assemblages suggest a transition from hydrostatic to suprahydrostatic fluid pressures over the depth range 3-5 km, with some evidence for near-lithostatic to hydrostatic pressure cycling towards the base of the seismogenic zone in the phyllonitic assemblages. Development of fault-fracture meshes through mixed-mode brittle failure in rock-masses with strong competence layering is promoted by low effective stress in the absence of thoroughgoing cohesionless faults that are favourably oriented for reactivation. Meshes may develop around normal faults in the near-surface under hydrostatic fluid pressures to depths determined by rock tensile strength, and at greater depths in overpressured portions of normal fault zones and at stress heterogeneities, especially dilational jogs. Overpressures localised within developing normal fault zones also determine the extent to which they may reutilise existing discontinuities (for example, low-angle thrust faults). Brittle failure mode plots demonstrate that reactivation of existing low-angle faults under vertical σ1 trajectories is only likely if fluid overpressures are localised within the fault zone and the surrounding rock retains significant tensile strength. Migrating pore fluids interact both statically and dynamically with normal faults. Static effects include consideration of the relative permeability of the faults with respect to the country rock, and juxtaposition effects which determine whether a fault is transmissive to flow or acts as an impermeable barrier. Strong directional permeability is expected in the subhorizontal σ2 direction parallel to intersections between minor faults, extension fractures, and stylolites. Three dynamic mechanisms tied to the seismic stress cycle may contribute to fluid redistribution: (i) cycling of mean stress coupled to shear stress, sometimes leading to postfailure expulsion of fluid from vertical fractures; (ii) suction pump action at dilational fault jogs; and, (iii) fault-valve action when a normal fault transects a seal capping either uniformly overpressured crust or overpressures localised to the immediate vicinity of the fault zone at depth. The combination of σ2 directional permeability with fluid redistribution from mean stress cycling may lead to hydraulic communication along strike, contributing to the protracted earthquake sequences that characterise normal fault systems.

Differential responsiveness in VEGF receptor subtypes to hypoxic stress in various tissues of plateau animals.

PubMed

Xie, Hui-Chun; Li, Jin-Gang; He, Jian-Ping

2017-05-04

With hypoxic stress, hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) are elevated and their responses are altered in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (Ochotona curzoniae)] as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. The results indicate that HIF-1alpha and VEGF are engaged in physiological functions under hypoxic environment. The purpose of the current study was to examine the protein levels of VEGF receptor subtypes (VEGFRs: VEGFR-1, VEGFR-2 and VEGFR-3) in the end organs, namely skeletal muscle, heart and lung in response to hypoxic stress. ELISA and Western blot analysis were employed to determine HIF-1alpha and the protein expression of VEGFRs in control animals and plateau pikas. We further blocked HIF-1alpha signal to determine if HIF-1alpha regulates alternations in VEGFRs in those tissues. We hypothesized that responsiveness of VEGFRs in the major end organs of plateau animals is differential with insult of hypoxic stress and is modulated by low oxygen sensitive HIF-1alpha. Our results show that hypoxic stress induced by exposure of lower O(2) for 6 h significantly increased the levels of VEGFR-2 in skeletal muscle, heart and lung and the increases were amplified in plateau pikas. Our results also demonstrate that hypoxic stress enhanced VEGFR-3 in lungs of plateau animals. Nonetheless, no significant alternations in VEGFR-1 were observed in those tissues with hypoxic stress. Moreover, we observed decreases of VEGFR-2 in skeletal muscle, heart and lung; and decreases of VEGFR-3 in lung following HIF-1alpha inhibition. Overall, our findings suggest that in plateau animals 1) responsiveness of VEGFRs is different under hypoxic environment; 2) amplified VEGFR-2 response appears in skeletal muscle, heart and lung, and enhanced VEGFR-3 response is mainly observed in lung; 3) HIF-1alpha plays a regulatory role in the levels of VEGFRs. Our results provide the underlying cellular and molecular mechanisms responsible for hypoxic environment in plateau animals, having an impact on research of physiological and ecological adaptive responses to acute or chronic hypoxic stress in humans who living at high attitude and who live at a normal sea level but suffer from hypoxic disorders.

A minimal titration model of the mammalian dynamical heat shock response

NASA Astrophysics Data System (ADS)

Sivéry, Aude; Courtade, Emmanuel; Thommen, Quentin

2016-12-01

Environmental stress, such as oxidative or heat stress, induces the activation of the heat shock response (HSR) and leads to an increase in the heat shock proteins (HSPs) level. These HSPs act as molecular chaperones to maintain cellular proteostasis. Controlled by highly intricate regulatory mechanisms, having stress-induced activation and feedback regulations with multiple partners, the HSR is still incompletely understood. In this context, we propose a minimal molecular model for the gene regulatory network of the HSR that reproduces quantitatively different heat shock experiments both on heat shock factor 1 (HSF1) and HSPs activities. This model, which is based on chemical kinetics laws, is kept with a low dimensionality without altering the biological interpretation of the model dynamics. This simplistic model highlights the titration of HSF1 by chaperones as the guiding line of the network. Moreover, by a steady states analysis of the network, three different temperature stress regimes appear: normal, acute, and chronic, where normal stress corresponds to pseudo thermal adaption. The protein triage that governs the fate of damaged proteins or the different stress regimes are consequences of the titration mechanism. The simplicity of the present model is of interest in order to study detailed modelling of cross regulation between the HSR and other major genetic networks like the cell cycle or the circadian clock.

Sensor for Direct Measurement of the Boundary Shear Stress in Fluid Flow

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Sherrit, Stewart; Chang, Zensheu; Chen, Beck; Widholm, Scott; Ostlund, Patrick

2011-01-01

The formation of scour patterns at bridge piers is driven by the forces at the boundary of the water flow. In most experimental scour studies, indirect processes have been applied to estimate the shear and normal stress using measured velocity profiles. The estimations are based on theoretical models and associated assumptions. However, the turbulence flow fields and boundary layer in the pier-scour region are very complex. In addition, available turbulence models cannot account accurately for the bed roughness effect. Direct measurement of the boundary shear and normal stress and their fluctuations are attractive alternatives. However, this approach is a challenging one especially for high spatial resolution and high fidelity measurements. The authors designed and fabricated a prototype miniature shear stress sensor including an EDM machined floating plate and a high-resolution laser optical encoder. Tests were performed both in air as well as operation in water with controlled flow. The sensor sensitivity, stability and signal-to-noise level were measured and evaluated. The detailed test results and a discussion of future work will be presented in this paper.

N-acetylcysteine normalizes the urea cycle and DNA repair in cells from patients with Batten disease.

PubMed

Kim, June-Bum; Lim, Nary; Kim, Sung-Jo; Heo, Tae-Hwe

2012-12-01

Batten disease is an inherited disorder characterized by early onset neurodegeneration due to the mutation of the CLN3 gene. The function of the CLN3 protein is not clear, but an association with oxidative stress has been proposed. Oxidative stress and DNA damage play critical roles in the pathogenesis of neurodegenerative diseases. Antioxidants are of interest because of their therapeutic potential for treating neurodegenerative diseases. We tested whether N-acetylcysteine (NAC), a well-known antioxidant, improves the pathology of cells from patients with Batten disease. At first, the expression levels of urea cycle components and DNA repair enzymes were compared between Batten disease cells and normal cells. We used both mRNA expression levels and Western blot analysis. We found that carbamoyl phosphate synthetase 1, an enzyme involved in the urea cycle, 8-oxoguanine DNA glycosylase 1 and DNA polymerase beta, enzymes involved in DNA repair, were expressed at higher levels in Batten disease cells than in normal cells. The treatment of Batten disease cells with NAC for 48 h attenuated activities of the urea cycle and of DNA repair, as indicated by the substantially decreased expression levels of carbamoyl phosphate synthetase 1, 8-oxoguanine DNA glycosylase 1 and DNA polymerase beta proteins compared with untreated Batten cells. NAC may serve in alleviating the burden of urea cycle and DNA repair processes in Batten disease cells. We propose that NAC may have beneficial effects in patients with Batten disease. Copyright © 2012 John Wiley & Sons, Ltd.

46 CFR Appendix A to Part 154 - Equivalent Stress

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in “xy...

46 CFR Appendix A to Part 154 - Equivalent Stress

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in “xy...

46 CFR Appendix A to Part 154 - Equivalent Stress

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in “xy...

46 CFR Appendix A to Part 154 - Equivalent Stress

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in “xy...

46 CFR Appendix A to Part 154 - Equivalent Stress

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in “xy...

Interspecies and Intraspecies Analysis of Trehalose Contents and the Biosynthesis Pathway Gene Family Reveals Crucial Roles of Trehalose in Osmotic-Stress Tolerance in Cassava

PubMed Central

Han, Bingying; Fu, Lili; Zhang, Dan; He, Xiuquan; Chen, Qiang; Peng, Ming; Zhang, Jiaming

2016-01-01

Trehalose is a nonreducing α,α-1,1-disaccharide in a wide range of organisms, and has diverse biological functions that range from serving as an energy source to acting as a protective/signal sugar. However, significant amounts of trehalose have rarely been detected in higher plants, and the function of trehalose in the drought-tolerant crop cassava (Manihot esculenta Crantz) is unclear. We measured soluble sugar concentrations of nine plant species with differing levels of drought tolerance and 41 cassava varieties using high-performance liquid chromatography with evaporative light-scattering detector (HPLC-ELSD). Significantly high amounts of trehalose were identified in drought-tolerant crops cassava, Jatropha curcas, and castor bean (Ricinus communis). All cassava varieties tested contained high amounts of trehalose, although their concentrations varied from 0.23 to 1.29 mg·g−1 fresh weight (FW), and the trehalose level was highly correlated with dehydration stress tolerance of detached leaves of the varieties. Moreover, the trehalose concentrations in cassava leaves increased 2.3–5.5 folds in response to osmotic stress simulated by 20% PEG 6000. Through database mining, 24 trehalose pathway genes, including 12 trehalose-6-phosphate synthases (TPS), 10 trehalose-6-phosphate phosphatases (TPP), and two trehalases were identified in cassava. Phylogenetic analysis indicated that there were four cassava TPS genes (MeTPS1–4) that were orthologous to the solely active TPS gene (AtTPS1 and OsTPS1) in Arabidopsis and rice, and a new TPP subfamily was identified in cassava, suggesting that the trehalose biosynthesis activities in cassava had potentially been enhanced in evolutionary history. RNA-seq analysis indicated that MeTPS1 was expressed at constitutionally high level before and after osmotic stress, while other trehalose pathway genes were either up-regulated or down-regulated, which may explain why cassava accumulated high level of trehalose under normal conditions. MeTPS1 was then transformed into tobacco (Nicotiana benthamiana). Results indicated that transgenic tobacco lines accumulated significant level of trehalose and possessed improved drought stress tolerance. In conclusion, cassava accumulated significantly high amount of trehalose under normal conditions due to multiplied trehalose biosynthesis gene families and constant expression of the active MeTPS1 gene. High levels of trehalose subsequently contributed to high drought stress tolerance. PMID:27420056

Deformability analysis of sickle blood using ektacytometry.

PubMed

Rabai, Miklos; Detterich, Jon A; Wenby, Rosalinda B; Hernandez, Tatiana M; Toth, Kalman; Meiselman, Herbert J; Wood, John C

2014-01-01

Sickle cell disease (SCD) is characterized by decreased erythrocyte deformability, microvessel occlusion and severe painful infarctions of different organs. Ektacytometry of SCD red blood cells (RBC) is made difficult by the presence of rigid, poorly-deformable irreversibly sickled cells (ISC) that do not align with the fluid shear field and distort the elliptical diffraction pattern seen with normal RBC. In operation, the computer software fits an outline to the diffraction pattern, then reports an elongation index (EI) at each shear stress based on the length and width of the fitted ellipse: EI=(length-width)/(length+width). Using a commercial ektacytometer (LORCA, Mechatronics Instruments, The Netherlands) we have approached the problem of ellipse fitting in two ways: (1) altering the height of the diffraction image on a computer monitor using an aperture within the camera lens; (2) altering the light intensity level (gray level) used by the software to fit the image to an elliptical shape. Neither of these methods affected deformability results (elongation index-shear stress relations) for normal RBC but did markedly affect results for SCD erythrocytes: (1) decreasing image height by 15% and 30% increased EI at moderate to high stresses; (2) progressively increasing the light level increased EI over a wide range of stresses. Fitting data obtained at different image heights using the Lineweaver-Burke routine yielded percentage ISC results in good agreement with microscopic cell counting. We suggest that these two relatively simple approaches allow minimizing artifacts due to the presence of rigid discs or ISC and also suggest the need for additional studies to evaluate the physiological relevance of deformability data obtained via these methods.

Melatonin prevents retinal oxidative stress and vascular changes in diabetic rats

PubMed Central

Özdemir, G; Ergün, Y; Bakariş, S; Kılınç, M; Durdu, H; Ganiyusufoğlu, E

2014-01-01

Purpose To evaluate the role of melatonin, an antioxidant agent, in diabetic oxidative stress and vascular damage. Methods Diabetes was induced in 21 male Wistar rats by intraperitoneal (IP) administration of streptozotocin and then the rats were equally and randomly allocated to diabetic, melatonin, and vehicle groups. Seven healthy normal rats with similar features comprised the control group as the fourth group. All animals were followed for 12 weeks. The melatonin group received IP melatonin daily and the vehicle group received 2.5% ethanol IP at the last month. At the end of 12 weeks, the rats were killed and retinas were harvested. The retinas were investigated for the existence of hypoxia-inducible factor 1-α (HIF-1α), vascular endothelial growth factor A (VEGF-A), and pigment epithelium-derived factor (PEDF) by ELISA. Retinal oxidative stress is quantitated by measuring nitrotyrosine and malondialdehyde levels. Retinal immunohistochemistry with antibody against CD31 antigen was carried out on retinal cross-sections. For statistics, ANOVA test was used for multiple comparisons. Results Hyperglycemia increased retinal oxidation as measured through levels of nitrotyrosine and malondialdehyde. Diabetic retinas are also associated with abnormal vascular changes such as dilatation and deformation. HIF-1α, VEGF-A, and PEDF were all increased because of diabetic injury. Melatonin showed a potential beneficial effect on retinopathy in diabetic rats. It decreased retinal nitrotyrosine and malondialdehyde levels, showing an antioxidative support. The vasculomodulator cytokines are decreased accordingly by melatonin therapy. Melatonin normalized retinal vascular changes as well. Conclusion Melatonin may show some advantage on diabetic vascular changes through decreasing oxidative stress and vessel-related cytokines. PMID:24924441

BAG3 affects the nucleocytoplasmic shuttling of HSF1 upon heat stress.

PubMed

Jin, Young-Hee; Ahn, Sang-Gun; Kim, Soo-A

2015-08-21

Bcl2-associated athoanogene (BAG) 3 is a member of the co-chaperone BAG family. It is induced by stressful stimuli such as heat shock and heavy metals, and it regulates cellular adaptive responses against stressful conditions. In this study, we identified a novel role for BAG3 in regulating the nuclear shuttling of HSF1 during heat stress. The expression level of BAG3 was induced by heat stress in HeLa cells. Interestingly, BAG3 rapidly translocalized to the nucleus upon heat stress. Immunoprecipitation assay showed that BAG3 interacts with HSF1 under normal and stressed conditions and co-translocalizes to the nucleus upon heat stress. We also demonstrated that BAG3 interacts with HSF1 via its BAG domain. Over-expression of BAG3 down-regulates the level of nuclear HSF1 by exporting it to the cytoplasm during the recovery period. Depletion of BAG3 using siRNA results in reduced nuclear HSF1 and decreased Hsp70 promoter activity. BAG3 in MEF(hsf1(-/-)) cells actively translocalizes to the nucleus upon heat stress suggesting that BAG3 plays a key role in the processing of the nucleocytoplasmic shuttling of HSF1 upon heat stress. Copyright © 2015 Elsevier Inc. All rights reserved.

Three-dimensional elastic-plastic finite-element analyses of constraint variations in cracked bodies

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Bigelow, C. A.; Shivakumar, K. N.

1993-01-01

Three-dimensional elastic-plastic (small-strain) finite-element analyses were used to study the stresses, deformations, and constraint variations around a straight-through crack in finite-thickness plates for an elastic-perfectly plastic material under monotonic and cyclic loading. Middle-crack tension specimens were analyzed for thicknesses ranging from 1.25 to 20 mm with various crack lengths. Three local constraint parameters, related to the normal, tangential, and hydrostatic stresses, showed similar variations along the crack front for a given thickness and applied stress level. Numerical analyses indicated that cyclic stress history and crack growth reduced the local constraint parameters in the interior of a plate, especially at high applied stress levels. A global constraint factor alpha(sub g) was defined to simulate three-dimensional effects in two-dimensional crack analyses. The global constraint factor was calculated as an average through-the-thickness value over the crack-front plastic region. Values of alpha(sub g) were found to be nearly independent of crack length and were related to the stress-intensity factor for a given thickness.

BAG3 affects the nucleocytoplasmic shuttling of HSF1 upon heat stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Young-Hee; Ahn, Sang-Gun; Kim, Soo-A., E-mail: ksooa@dongguk.ac.kr

2015-08-21

Bcl2-associated athoanogene (BAG) 3 is a member of the co-chaperone BAG family. It is induced by stressful stimuli such as heat shock and heavy metals, and it regulates cellular adaptive responses against stressful conditions. In this study, we identified a novel role for BAG3 in regulating the nuclear shuttling of HSF1 during heat stress. The expression level of BAG3 was induced by heat stress in HeLa cells. Interestingly, BAG3 rapidly translocalized to the nucleus upon heat stress. Immunoprecipitation assay showed that BAG3 interacts with HSF1 under normal and stressed conditions and co-translocalizes to the nucleus upon heat stress. We alsomore » demonstrated that BAG3 interacts with HSF1 via its BAG domain. Over-expression of BAG3 down-regulates the level of nuclear HSF1 by exporting it to the cytoplasm during the recovery period. Depletion of BAG3 using siRNA results in reduced nuclear HSF1 and decreased Hsp70 promoter activity. BAG3 in MEF(hsf1{sup −/−}) cells actively translocalizes to the nucleus upon heat stress suggesting that BAG3 plays a key role in the processing of the nucleocytoplasmic shuttling of HSF1 upon heat stress. - Highlights: • The expression level of BAG3 is induced by heat stress. • BAG3 translocates to the nucleus upon heat stress. • BAG3 interacts with HSF1 and co-localizes to the nucleus. • BAG3 is a key regulator for HSF1 nuclear shuttling.« less

DinB Upregulation Is the Sole Role of the SOS Response in Stress-Induced Mutagenesis in Escherichia coli

PubMed Central

Galhardo, Rodrigo S.; Do, Robert; Yamada, Masami; Friedberg, Errol C.; Hastings, P. J.; Nohmi, Takehiko; Rosenberg, Susan M.

2009-01-01

Stress-induced mutagenesis is a collection of mechanisms observed in bacterial, yeast, and human cells in which adverse conditions provoke mutagenesis, often under the control of stress responses. Control of mutagenesis by stress responses may accelerate evolution specifically when cells are maladapted to their environments, i.e., are stressed. It is therefore important to understand how stress responses increase mutagenesis. In the Escherichia coli Lac assay, stress-induced point mutagenesis requires induction of at least two stress responses: the RpoS-controlled general/starvation stress response and the SOS DNA-damage response, both of which upregulate DinB error-prone DNA polymerase, among other genes required for Lac mutagenesis. We show that upregulation of DinB is the only aspect of the SOS response needed for stress-induced mutagenesis. We constructed two dinB(oc) (operator-constitutive) mutants. Both produce SOS-induced levels of DinB constitutively. We find that both dinB(oc) alleles fully suppress the phenotype of constitutively SOS-“off” lexA(Ind−) mutant cells, restoring normal levels of stress-induced mutagenesis. Thus, dinB is the only SOS gene required at induced levels for stress-induced point mutagenesis. Furthermore, although spontaneous SOS induction has been observed to occur in only a small fraction of cells, upregulation of dinB by the dinB(oc) alleles in all cells does not promote a further increase in mutagenesis, implying that SOS induction of DinB, although necessary, is insufficient to differentiate cells into a hypermutable condition. PMID:19270270

On the continuity of mean total normal stress in geometrical multiscale cardiovascular problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanco, Pablo J., E-mail: pjblanco@lncc.br; INCT-MACC, Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica, Petrópolis; Deparis, Simone, E-mail: simone.deparis@epfl.ch

2013-10-15

In this work an iterative strategy to implicitly couple dimensionally-heterogeneous blood flow models accounting for the continuity of mean total normal stress at interface boundaries is developed. Conservation of mean total normal stress in the coupling of heterogeneous models is mandatory to satisfy energetic consistency between them. Nevertheless, existing methodologies are based on modifications of the Navier–Stokes variational formulation, which are undesired when dealing with fluid–structure interaction or black box codes. The proposed methodology makes possible to couple one-dimensional and three-dimensional fluid–structure interaction models, enforcing the continuity of mean total normal stress while just imposing flow rate data or evenmore » the classical Neumann boundary data to the models. This is accomplished by modifying an existing iterative algorithm, which is also able to account for the continuity of the vessel area, when required. Comparisons are performed to assess differences in the convergence properties of the algorithms when considering the continuity of mean normal stress and the continuity of mean total normal stress for a wide range of flow regimes. Finally, examples in the physiological regime are shown to evaluate the importance, or not, of considering the continuity of mean total normal stress in hemodynamics simulations.« less

Statistical Characterization of the Mechanical Parameters of Intact Rock Under Triaxial Compression: An Experimental Proof of the Jinping Marble

NASA Astrophysics Data System (ADS)

Jiang, Quan; Zhong, Shan; Cui, Jie; Feng, Xia-Ting; Song, Leibo

2016-12-01

We investigated the statistical characteristics and probability distribution of the mechanical parameters of natural rock using triaxial compression tests. Twenty cores of Jinping marble were tested under each different levels of confining stress (i.e., 5, 10, 20, 30, and 40 MPa). From these full stress-strain data, we summarized the numerical characteristics and determined the probability distribution form of several important mechanical parameters, including deformational parameters, characteristic strength, characteristic strains, and failure angle. The statistical proofs relating to the mechanical parameters of rock presented new information about the marble's probabilistic distribution characteristics. The normal and log-normal distributions were appropriate for describing random strengths of rock; the coefficients of variation of the peak strengths had no relationship to the confining stress; the only acceptable random distribution for both Young's elastic modulus and Poisson's ratio was the log-normal function; and the cohesive strength had a different probability distribution pattern than the frictional angle. The triaxial tests and statistical analysis also provided experimental evidence for deciding the minimum reliable number of experimental sample and for picking appropriate parameter distributions to use in reliability calculations for rock engineering.

Ketogenic diets as an adjuvant cancer therapy: History and potential mechanism

PubMed Central

Allen, Bryan G.; Bhatia, Sudershan K.; Anderson, Carryn M.; Eichenberger-Gilmore, Julie M.; Sibenaller, Zita A.; Mapuskar, Kranti A.; Schoenfeld, Joshua D.; Buatti, John M.; Spitz, Douglas R.; Fath, Melissa A.

2014-01-01

Cancer cells, relative to normal cells, demonstrate significant alterations in metabolism that are proposed to result in increased steady-state levels of mitochondrial-derived reactive oxygen species (ROS) such as O2•−and H2O2. It has also been proposed that cancer cells increase glucose and hydroperoxide metabolism to compensate for increased levels of ROS. Given this theoretical construct, it is reasonable to propose that forcing cancer cells to use mitochondrial oxidative metabolism by feeding ketogenic diets that are high in fats and low in glucose and other carbohydrates, would selectively cause metabolic oxidative stress in cancer versus normal cells. Increased metabolic oxidative stress in cancer cells would in turn be predicted to selectively sensitize cancer cells to conventional radiation and chemotherapies. This review summarizes the evidence supporting the hypothesis that ketogenic diets may be safely used as an adjuvant therapy to conventional radiation and chemotherapies and discusses the proposed mechanisms by which ketogenic diets may enhance cancer cell therapeutic responses. PMID:25460731

[The investigation of the influence of cryopreservation and inbreeding on the variability of morphological characteristics of the evening-primrose biennial (Oenothera biennis L.)].

PubMed

Chetviverikova, E P; Iashina, S G; Shabaeva, E V; Egorova, E F; Iashina, A V

2005-01-01

The effect of deep freezing of seeds at -196 degrees C (-320.8 degrees Fahrenheit) and inbreeding on the morphological characteristics of the evening-primrose biennal (Oenothera biennis L.), such as the size of plant parts and the amount of fruits, cauline nodes, and generative and vegetative shoots was investigated. The variation coefficients for these characteristics after treatment with low temperatures and inbreeding were calculated. It was shown that the characteristics of plant size show a low and a middle level of variability in the control group. The variation curves for these characteristics are similar to normal distribution curves. After stresses they slightly change or remain invariant. Large adventive shoots show a high level of variability. The distribution of the results in this case significantly differs from the normal. The branching of plants changes after both stress factors: the amount of all kinds of shoots decreases by half or even more.

Hypoglycemic and antioxidant potential of coconut water in experimental diabetes.

PubMed

Preetha, P P; Devi, V Girija; Rajamohan, T

2012-07-01

Coconut water is a natural nutritious beverage that contains several biologically active compounds. The present study aims to evaluate the hypoglycemic and antioxidant effects of mature coconut water (MCW) on alloxan-induced diabetes in experimental rats. The experimental animals were divided into four groups - normal control, normal rats treated with MCW, diabetic control and diabetic rats treated with MCW. The blood glucose, plasma insulin, hemoglobin, glycated hemoglobin, activities of the various antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase) and lipid peroxidation markers (malondialdehyde, hydroperoxides and conjugated dienes) were evaluated in all the groups. The results indicate that the diabetic animals treated with MCW had decreased blood glucose levels and reduced oxidative stress induced by alloxan, which was evident from the increased activities of the antioxidant enzymes and the decreased levels of the lipid peroxidation products. The overall results indicate that MCW significantly attenuated hyperglycemia and oxidative stress in alloxan-induced diabetic rats, indicating the therapeutic potential of MCW.

Normal Human Fibroblasts Are Resistant to RAS-Induced Senescence

PubMed Central

Benanti, Jennifer A.; Galloway, Denise A.

2004-01-01

Oncogenic stimuli are thought to induce senescence in normal cells in order to protect against transformation and to induce proliferation in cells with altered p53 and/or retinoblastoma (Rb) pathways. In human fibroblasts, RAS initiates senescence through upregulation of the cyclin-dependent kinase inhibitor p16INK4A. We show here that in contrast to cultured fibroblast strains, freshly isolated normal fibroblasts are resistant to RAS-induced senescence and instead show some characteristics of transformation. RAS did not induce growth arrest or expression of senescence-associated β-galactosidase, and Rb remained hyperphosphorylated despite elevated levels of p16. Instead, RAS promoted anchorage-independent growth of normal fibroblasts, although expression of hTert with RAS increased colony formation and allowed normal fibroblasts to bypass contact inhibition. To test the hypothesis that p16 levels determine how cells respond to RAS, we expressed RAS in freshly isolated fibroblasts that expressed very low levels of p16, in hTert-immortalized fibroblasts that had accumulated intermediate levels of p16, and in IMR90 fibroblasts with high levels of p16. RAS induced growth arrest in cells with higher p16 levels, and this effect was reversed by p16 knockdown in the hTert-immortalized fibroblasts. These findings indicate that culture-imposed stress sensitizes cells to RAS-induced arrest, whereas early passage cells do not arrest in response to RAS. PMID:15024073

Vitamin B12-responsive neuropathies: A case series.

PubMed

Solomon, Lawrence R

2016-05-01

Neuropathies often accompany vitamin B12 deficiency. Since many neuropathies are linked to oxidative stress and since B12 has both antioxidant and neurotrophic properties, B12 may also be effective treatment in non-deficient subjects. Thus, the characteristics and predictors of B12-responsive neuropathies and their relationship to disorders associated with increased oxidative stress (oxidant risks) were examined. Retrospective review of 78 subjects with neurological abnormalities treated with B12 and evaluated by the measurement of B12 and the B12-dependent metabolites, methylmalonic acid (MMA), and homocysteine. Sixty-five subjects had neurological improvement (83%), including 35 with other known causes of neuropathy. Only two responders had B12-responsive macrocytosis. Pretherapy B12, MMA, and homocysteine values were normal in 72, 33 and 54% of responders, with all three normal in 23%. Moreover, B12 therapy did not significantly decrease elevated MMA and homocysteine levels in 20 and 37%, respectively, of responders tested but did decrease both metabolites in 75% of evaluable non-responders. At least one oxidant risk was present in 41 of the 46 responders with normal B12 levels (89%). Oral therapy was effective, but parenteral B12 improved responses in four subjects. B12-responsive neuropathies are thus (1) common even when confounding disorders are present; (2) dissociated from the presence of hematological abnormalities; (3) dissociated from the presence of B12-responsive metabolical abnormalities; and (4) associated with the presence of oxidant risks when B12 levels are normal. Since no predictors of responses to B12 therapy were identified, empiric trials with parenteral B12 should be considered in appropriate subjects.

When endocrinology and democracy collide: emotions, cortisol and voting at national elections.

PubMed

Waismel-Manor, Israel; Ifergane, Gal; Cohen, Hagit

2011-11-01

Faced with stressful experiences, such as uncertainty or novelty, the adrenal glands secrete glucocorticoid hormones to help us cope with stress. Since many decision-making situations are stressful, there is reason to believe that voting is a stressful event. In this study, we asked voters in Israel's national election (N=113) to report on their general affective state immediately before entering the polling place using the Positive Affect Negative Affect Schedule (PANAS) and to provide us with a saliva sample through which we could evaluate their cortisol levels. Compared to a second sample of voters who reported their affective state on election night (N=70), we found that voters at the ballot box had higher positive and negative affect. Moreover, our voters at the polling place exhibited cortisol levels that were significantly higher than their own normal levels obtained on a similar day, and significantly higher than those of a second control group sampled the day after the elections (N=6). Our data demonstrate that elections are exciting, yet stressful events, and it is this stress, among other factors, that elevates the cortisol levels of voters. Since elevated cortisol has been found to affect memory consolidation, impair memory retrieval and lead to risk-seeking behavior, we discuss how these outcomes of elevated cortisol levels may affect voting in general and the field of electoral studies in particular. Copyright © 2011 Elsevier B.V. and ECNP. All rights reserved.

Accurate Thermal Stresses for Beams: Normal Stress

NASA Technical Reports Server (NTRS)

Johnson, Theodore F.; Pilkey, Walter D.

2002-01-01

Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

Accurate Thermal Stresses for Beams: Normal Stress

NASA Technical Reports Server (NTRS)

Johnson, Theodore F.; Pilkey, Walter D.

2003-01-01

Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

Comparative evaluation of serum antioxidant levels in periodontally diseased patients: An interventional study

PubMed Central

Thomas, Biju; Madani, Shabeer Mohamed; Prasad, B. Rajendra; Kumari, Suchetha

2014-01-01

Background: Periodontal disease is an immune-inflammatory disease characterized by connective tissue breakdown, loss of attachment and alveolar bone resorption. In normal physiology, there is a dynamic equilibrium between reactive oxygen species activity and antioxidant defense capacity and when that equilibrium shifts in favor of reactive oxygen species, oxidative stress results. Oxidative stress is thought to play a causative role in the pathogenesis of periodontal diseases. Catalase (CAT) protects cells from hydrogen peroxide generated within them. Even though, CAT is not essential for some cell types under normal conditions, it plays an important role countering the effects of oxidative stress on the cell. Aim: This study was designed to estimate and compare the CAT and total antioxidant capacity (TAOC) levels in the serum of periodontitis, gingivitis, and healthy individuals before and after nonsurgical periodontal therapy. Materials and Methods: This study was conducted in the Department of Periodontics, A. B. Shetty Memorial Institute of Dental Sciences, Deralakatte, Mangalore. The study was designed as a single blinded interventional study comprising of 75 subjects, inclusive of both sexes and divided into three groups of 25 patients each. Patients were categorized into chronic periodontitis, gingivitis and healthy. The severity of inflammation was assessed by using gingival index and pocket probing depth. Biochemical analysis was done to estimate the TAOC and CAT levels before and after nonsurgical periodontal therapy. Results obtained were then statistically analyzed using ANOVA test and paired t-test. Results: The results showed a higher level of serum TAOC and CAT in the healthy group compared with the other groups. The difference was found to be statistically significant (P < 0.0001). The posttreatment levels of TAOC were statistically higher than the pretreatment levels in periodontitis group. PMID:25191070

Analysis tool and methodology design for electronic vibration stress understanding and prediction

NASA Astrophysics Data System (ADS)

Hsieh, Sheng-Jen; Crane, Robert L.; Sathish, Shamachary

2005-03-01

The objectives of this research were to (1) understand the impact of vibration on electronic components under ultrasound excitation; (2) model the thermal profile presented under vibration stress; and (3) predict stress level given a thermal profile of an electronic component. Research tasks included: (1) retrofit of current ultrasonic/infrared nondestructive testing system with sensory devices for temperature readings; (2) design of software tool to process images acquired from the ultrasonic/infrared system; (3) developing hypotheses and conducting experiments; and (4) modeling and evaluation of electronic vibration stress levels using a neural network model. Results suggest that (1) an ultrasonic/infrared system can be used to mimic short burst high vibration loads for electronics components; (2) temperature readings for electronic components under vibration stress are consistent and repeatable; (3) as stress load and excitation time increase, temperature differences also increase; (4) components that are subjected to a relatively high pre-stress load, followed by a normal operating load, have a higher heating rate and lower cooling rate. These findings are based on grayscale changes in images captured during experimentation. Discriminating variables and a neural network model were designed to predict stress levels given temperature and/or grayscale readings. Preliminary results suggest a 15.3% error when using grayscale change rate and 12.8% error when using average heating rate within the neural network model. Data were obtained from a high stress point (the corner) of the chip.

Effects of shear stress on the microalgae Chaetoceros muelleri

PubMed Central

van der Goot, Atze J.; Norsker, Niels-Henrik; Wijffels, René H.

2010-01-01

The effect of shear stress on the viability of Chaetoceros muelleri was studied using a combination of a rheometer and dedicated shearing devices. Different levels of shear stress were applied by varying the shear rates and the medium viscosities. It was possible to quantify the effect of shear stress over a wide range, whilst preserving laminar flow conditions through the use of a thickening agent. The threshold value at which the viability of algae was negatively influenced was between 1 and 1.3 Pa. Beyond the threshold value the viability decreased suddenly to values between 52 and 66%. The effect of shear stress was almost time independent compared to normal microalgae cultivation times. The main shear stress effect was obtained within 1 min, with a secondary effect of up to 8 min. PMID:20191365

Characteristics of Asperity Damage and Its Influence on the Shear Behavior of Granite Joints

NASA Astrophysics Data System (ADS)

Meng, Fanzhen; Zhou, Hui; Wang, Zaiquan; Zhang, Chuanqing; Li, Shaojun; Zhang, Liming; Kong, Liang

2018-02-01

Surface roughness significantly affects the shear behavior of rock joints; thus, studies on the asperity damage characteristics and its influence on the shear behavior of joints are extremely important. In this paper, shear tests were conducted on tensile granite joints; asperity damage was evaluated based on acoustic emission (AE) events; and the influence of asperity damage on joint shear behavior was analyzed. The results indicated that the total AE events tended to increase with normal stress. In addition, the asperity damage initiation shear stress, which is defined as the transition point from slow growth to rapid growth in the cumulative events curve, was approximately 0.485 of the peak shear strength regardless of the normal stress. Moreover, 63-85% of the AE events were generated after the peak shear stress, indicating that most of the damage occurred in this stage. Both the dilation and the total AE events decreased with shear cycles because of the damage inflicted on asperities during the previous shear cycle. Two stages were observed in the normal displacement curves under low normal stress, whereas three stages (compression, dilation and compression again) were observed at a higher normal stress; the second compression stage may be caused by tensile failure outside the shear plane. The magnitude of the normal stress and the state of asperity are two important factors controlling the post-peak stress drop and stick-slip of granite joints. Serious deterioration of asperities will stop stick-slip from recurring under the same normal stress because the ability to accumulate energy is decreased. The AE b-value increases with the number of shear cycles, indicating that the stress concentration inside the fault plane is reduced because of asperity damage; thus, the potential for dynamic disasters, such as fault-slip rockbursts, will be decreased.

Modeling and Studying the Effect of Texture and Elastic Anisotropy of Copper Microstructure in Nanoscale Interconnects on Reliability in Integrated Circuits

NASA Astrophysics Data System (ADS)

Basavalingappa, Adarsh

Copper interconnects are typically polycrystalline and follow a lognormal grain size distribution. Polycrystalline copper interconnect microstructures with a lognormal grain size distribution were obtained with a Voronoi tessellation approach. The interconnect structures thus obtained were used to study grain growth mechanisms, grain boundary scattering, scattering dependent resistance of interconnects, stress evolution, vacancy migration, reliability life times, impact of orientation dependent anisotropy on various mechanisms, etc. In this work, the microstructures were used to study the impact of microstructure and elastic anisotropy of copper on thermal and electromigration induced failure. A test structure with copper and bulk moduli values was modeled to do a comparative study with the test structures with textured microstructure and elastic anisotropy. By subjecting the modeled test structure to a thermal stress by ramping temperature down from 400 °C to 100 °C, a significant variation in normal stresses and pressure were observed at the grain boundaries. This variation in normal stresses and hydrostatic stresses at the grain boundaries was found to be dependent on the orientation, dimensions, surroundings, and location of the grains. This may introduce new weak points within the metal line where normal stresses can be very high depending on the orientation of the grains leading to delamination and accumulation sites for vacancies. Further, the hydrostatic stress gradients act as a driving force for vacancy migration. The normal stresses can exceed certain grain orientation dependent critical threshold values and induce delamination at the copper and cap material interface, thereby leading to void nucleation and growth. Modeled test structures were subjected to a series of copper depositions at 250 °C followed by copper etch at 25 °C to obtain initial stress conditions. Then the modeled test structures were subjected to 100,000 hours ( 11.4 years) of simulated thermal stress at an elevated temperature of 150 °C. Vacancy migration due to concentration gradients, thermal gradients, and mechanical stress gradients were considered under the applied thermal stress. As a result, relatively high concentrations of vacancies were observed in the test structure due to a driving force caused by the pressure gradients resulting from the elastic anisotropy of copper. The grain growth mechanism was not considered in these simulations. Studies with two grain analysis demonstrated that the stress gradients developed will be severe when (100) grains are adjacent to (111) grains, therefore making them the weak points for potentially reliability failures. Ilan Blech discovered that electromigration occurs above a critical product of the current density and metal length, commonly referred as Blech condition. Electromigration stress simulations in this work were carried out by subjecting test structures to scaled current densities to overcome the Blech condition of (jL)crit for small dimensions of test structure and the low temperature stress condition used. Vacancy migration under the electromigration stress conditions was considered along with the vacancy migration induced stress evolution. A simple void growth model was used which assumes voids start to form when vacancies reach a critical level. Increase of vacancies in a localized region increases the resistance of the metal line. Considering a 10% increase in resistance as a failure criterion, the distributions of failure times were obtained for given electromigration stress conditions. Bimodal/multimodal failure distributions were obtained as a result. The sigma values were slightly lower than the ones commonly observed from experiments. The anisotropy of the elastic moduli of copper leads to the development of significantly different stress values which are dependent on the orientation of the grains. This results in some grains having higher normal stress than the others. This grain orientation dependent normal stress can reach a critical stress necessary to induce delamination at the copper and cap interface. Time taken to reach critical stress was considered as time to fail and distributions of failure times were obtained for structures with different grain orientations in the microstructure for different critical stress values. The sigma values of the failure distributions thus obtained for different constant critical stress values had a strong dependence of on the critical stress. It is therefore critical to use the appropriate critical stress value for the delamination of copper and cap interface. The critical stress necessary to overcome the local adhesion of the copper and the cap material interface is dependent on grain orientation of the copper. Simulations were carried out by considering grain orientation dependent critical normal stress values as failure criteria. The sigma value thus obtained with selected critical stress values were comparable to sigma values commonly observed from experiments.

Effects of human recombinant erythropoietin on differentiation and distribution of erythroid progenitor cells on murine medullary and splenic erythropoiesis during hypoxia and post-hypoxia.

PubMed

Mide, S M; Huygens, P; Bozzini, C E; Fernandez Pol, J A

2001-01-01

Hemopoietic cells, the extracellular matrix, growth factors and the microenvironment are involved in the regulation of hemopoiesis. Although the regulation of erythropoiesis is well understood at the cellular level in vivo and in vitro, the role of hemopoietic sites of erythroid progenitors production has not been well defined in both steady state conditions and in stress erythropoiesis. In this study we examined the qualitative erythroid differentiation and quantitative changes of the erythroid progenitors in different erythropoietic organs during erythropoiesis of stress in a hypoxia-induced polycythemia and post-hypoxic changes in a mice model. Chronic intermittent exposure to hypobaric hypoxia induced polycythemia in mice and the post-hypoxic period was characterized by total suppression of erythropoiesis. The number and distribution in hemopoietic sites of Immature Erythroid Burst (BFU-EI), Mature Erythroid Burst (BFU-EM) and Erythroid Colony Forming Units (CFU-E) was evaluated in bone marrow and spleen of hypoxic and post-hypoxic mice after removal from the chamber. The number of BFU-EI and CFU-E, was evaluated in both femoral bone marrow and spleen of ex-hypoxic polycythemic mice, at two times intervals after the end of hypoxia. We found that in both bone marrow and spleen, the kinetics of the CFU-E pool was characterized by a sharp fall from above normal to lower than normal levels. BFU-EM increased from normal to higher than normal levels. These results have been correlated with both erythropoietin (EPO) and the erythropoietic activity. The results show that EPO levels largely control both the differentiation and the amplification of the CFU-E pool and they suggest that EPO may acts as a "survival factor" at the CFU-E level and/or increase the flow of cells from BFU-E to CFU-E. After the termination of the period of hypoxia and during post-hypoxia there was a reduction in EPO production which subsequently caused a depletion of the CFU-E population, indicating that the size of the CFU-E pool is EPO-dependent. After the injection of 1U of recombinant human erythropoietin (rHuEPO) the size of that pool was increased and the pool of BFU-EI was decreased. It is noteworthy that our studies show that the spleen functions as a large reservoir of erythroid precursors for hypoxia-induced stress erythropoiesis.

Identification of Reference Genes and Analysis of Heat Shock Protein Gene Expression in Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum, after Exposure to Heat Stress.

PubMed

Liu, Yong-Nan; Lu, Xiao-Xiao; Ren, Ang; Shi, Liang; Jiang, Ai-Liang; Yu, Han-Shou; Zhao, Ming-Wen

2017-01-01

Ganoderma lucidum has been considered an emerging model species for studying how environmental factors regulate the growth, development, and secondary metabolism of Basidiomycetes. Heat stress, which is one of the most important environmental abiotic stresses, seriously affects the growth, development, and yield of microorganisms. Understanding the response to heat stress has gradually become a hotspot in microorganism research. But suitable reference genes for expression analysis under heat stress have not been reported in G. lucidum. In this study, we systematically identified 11 candidate reference genes that were measured using reverse transcriptase quantitative polymerase chain reaction, and the gene expression stability was analyzed under heat stress conditions using geNorm and NormFinder. The results show that 5 reference genes-CYP and TIF, followed by UCE2, ACTIN, and UBQ1-are the most stable genes under our experimental conditions. Moreover, the relative expression levels of 3 heat stress response genes (hsp17.4, hsp70, and hsp90) were analyzed under heat stress conditions with different normalization strategies. The results show that use of a gene with unstable expression (SAND) as the reference gene leads to biased data and misinterpretations of the target gene expression level under heat stress.

Overexpression of a Common Wheat Gene TaSnRK2.8 Enhances Tolerance to Drought, Salt and Low Temperature in Arabidopsis

PubMed Central

Zhang, Hongying; Mao, Xinguo; Wang, Chengshe; Jing, Ruilian

2010-01-01

Drought, salinity and low temperatures are major factors limiting crop productivity and quality. Sucrose non-fermenting1-related protein kinase 2 (SnRK2) plays a key role in abiotic stress signaling in plants. In this study, TaSnRK2.8, a SnRK2 member in wheat, was cloned and its functions under multi-stress conditions were characterized. Subcellular localization showed the presence of TaSnRK2.8 in the cell membrane, cytoplasm and nucleus. Expression pattern analyses in wheat revealed that TaSnRK2.8 was involved in response to PEG, NaCl and cold stresses, and possibly participates in ABA-dependent signal transduction pathways. To investigate its role under various environmental stresses, TaSnRK2.8 was transferred to Arabidopsis under control of the CaMV-35S promoter. Overexpression of TaSnRK2.8 resulted in enhanced tolerance to drought, salt and cold stresses, further confirmed by longer primary roots and various physiological characteristics, including higher relative water content, strengthened cell membrane stability, significantly lower osmotic potential, more chlorophyll content, and enhanced PSII activity. Meanwhile, TaSnRK2.8 plants had significantly lower total soluble sugar levels under normal growing conditions, suggesting that TaSnRK2.8 might be involved in carbohydrate metabolism. Moreover, the transcript levels of ABA biosynthesis (ABA1, ABA2), ABA signaling (ABI3, ABI4, ABI5), stress-responsive genes, including two ABA-dependent genes (RD20A, RD29B) and three ABA-independent genes (CBF1, CBF2, CBF3), were generally higher in TaSnRK2.8 plants than in WT/GFP controls under normal/stress conditions. Our results suggest that TaSnRK2.8 may act as a regulatory factor involved in a multiple stress response pathways. PMID:21209856

Nuclear DNA Methylation and Chromatin Condensation Phenotypes Are Distinct Between Normally Proliferating/Aging, Rapidly Growing/Immortal, and Senescent Cells

PubMed Central

Gertych, Arkadiusz; Tajbakhsh, Jian

2013-01-01

This study reports on probing the utility of in situ chromatin texture features such as nuclear DNA methylation and chromatin condensation patterns — visualized by fluorescent staining and evaluated by dedicated three-dimensional (3D) quantitative and high-throughput cell-by-cell image analysis — in assessing the proliferative capacity, i.e. growth behavior of cells: to provide a more dynamic picture of a cell population with potential implications in basic science, cancer diagnostics/prognostics and therapeutic drug development. Two types of primary cells and four different cancer cell lines were propagated and subjected to cell-counting, flow cytometry, confocal imaging, and 3D image analysis at various points in culture. Additionally a subset of primary and cancer cells was accelerated into senescence by oxidative stress. DNA methylation and chromatin condensation levels decreased with declining doubling times when primary cells aged in culture with the lowest levels reached at the stage of proliferative senescence. In comparison, immortal cancer cells with constant but higher doubling times mostly displayed lower and constant levels of the two in situ-derived features. However, stress-induced senescent primary and cancer cells showed similar levels of these features compared with primary cells that had reached natural growth arrest. With regards to global DNA methylation and chromatin condensation levels, aggressively growing cancer cells seem to take an intermediate level between normally proliferating and senescent cells. Thus, normal cells apparently reach cancer-cell equivalent stages of the two parameters at some point in aging, which might challenge phenotypic distinction between these two types of cells. Companion high-resolution molecular profiling could provide information on possible underlying differences that would explain benign versus malign cell growth behaviors. PMID:23562889

Nuclear DNA methylation and chromatin condensation phenotypes are distinct between normally proliferating/aging, rapidly growing/immortal, and senescent cells.

PubMed

Oh, Jin Ho; Gertych, Arkadiusz; Tajbakhsh, Jian

2013-03-01

This study reports on probing the utility of in situ chromatin texture features such as nuclear DNA methylation and chromatin condensation patterns - visualized by fluorescent staining and evaluated by dedicated three-dimensional (3D) quantitative and high-throughput cell-by-cell image analysis - in assessing the proliferative capacity, i.e. growth behavior of cells: to provide a more dynamic picture of a cell population with potential implications in basic science, cancer diagnostics/prognostics and therapeutic drug development. Two types of primary cells and four different cancer cell lines were propagated and subjected to cell-counting, flow cytometry, confocal imaging, and 3D image analysis at various points in culture. Additionally a subset of primary and cancer cells was accelerated into senescence by oxidative stress. DNA methylation and chromatin condensation levels decreased with declining doubling times when primary cells aged in culture with the lowest levels reached at the stage of proliferative senescence. In comparison, immortal cancer cells with constant but higher doubling times mostly displayed lower and constant levels of the two in situ-derived features. However, stress-induced senescent primary and cancer cells showed similar levels of these features compared with primary cells that had reached natural growth arrest. With regards to global DNA methylation and chromatin condensation levels, aggressively growing cancer cells seem to take an intermediate level between normally proliferating and senescent cells. Thus, normal cells apparently reach cancer-cell equivalent stages of the two parameters at some point in aging, which might challenge phenotypic distinction between these two types of cells. Companion high-resolution molecular profiling could provide information on possible underlying differences that would explain benign versus malign cell growth behaviors.

The biologic effects of grounding the human body during sleep as measured by cortisol levels and subjective reporting of sleep, pain, and stress.

PubMed

Ghaly, Maurice; Teplitz, Dale

2004-10-01

Diurnal cortisol secretion levels were measured and circadian cortisol profiles were evaluated in a pilot study conducted to test the hypothesis that grounding the human body to earth during sleep will result in quantifiable changes in cortisol. It was also hypothesized that grounding the human body would result in changes in sleep, pain, and stress (anxiety, depression, irritability), as measured by subjective reporting. Twelve (12) subjects with complaints of sleep dysfunction, pain, and stress were grounded to earth during sleep for 8 weeks in their own beds using a conductive mattress pad. Saliva tests were administered to establish pregrounding baseline cortisol levels. Levels were obtained at 4-hour intervals for a 24-hour period to determine the circadian cortisol profile. Cortisol testing was repeated at week 6. Subjective symptoms of sleep dysfunction, pain, and stress were reported daily throughout the 8-week test period. Measurable improvements in diurnal cortisol profiles were observed, with cortisol levels significantly reduced during night-time sleep. Subjects' 24-hour circadian cortisol profiles showed a trend toward normalization. Subjectively reported symptoms, including sleep dysfunction, pain, and stress, were reduced or eliminated in nearly all subjects. Results indicate that grounding the human body to earth ("earthing") during sleep reduces night-time levels of cortisol and resynchronizes cortisol hormone secretion more in alignment with the natural 24-hour circadian rhythm profile. Changes were most apparent in females. Furthermore, subjective reporting indicates that grounding the human body to earth during sleep improves sleep and reduces pain and stress.

Effect of Hypergravity on the Level of Heat Shock Proteins 70 and 90 in Pea Seedlings

NASA Astrophysics Data System (ADS)

Kozeko, Liudmyla; Kordyum, Elizabeth

2009-01-01

Exposure to hypergravity induces significant changes in gene expression of plants which are indicative of stress conditions. A substantial part of the general stress response is up-regulation of heat shock proteins (Hsp) which function as molecular chaperones. The objective of this research was to test the possible changes in the Hsp70 and Hsp90 level in response to short-term hypergravity exposure. In this study 5-day-old etiolated pea seedlings were exposed to centrifuge-induced hypergravity (3-14 g) for 15 min and 1 h and a part of the seedlings was sampled at 1.5 and 24 h after the exposures. Western blot analysis showed time-dependent changes in Hsp70 and Hsp90 levels: an increase under hypergravity and a tendency towards recovery of the normal content during re-adaptation. The quantity and time of their expression was correlated with the g-force level. These data suggest that short-term hypergravity acts as a stress which could increase the risk of protein denaturation and aggregation. Molecular chaperons induced during the stress may have an essential role in counteracting this risk.

The relaxation response: reducing stress and improving cognition in healthy aging adults.

PubMed

Galvin, Jennifer A; Benson, Herbert; Deckro, Gloria R; Fricchione, Gregory L; Dusek, Jeffery A

2006-08-01

Aging adults are vulnerable to the effects of a negative emotional state. The relaxation response (RR) is a mind-body intervention that counteracts the harmful effects of stress. Previous studies with relaxation techniques have shown the non-pharmacological benefit of reducing stress and improving the memory of healthy older adults. Our pilot study evaluated whether a RR training program would decrease anxiety levels, improve attention, declarative memory performance and/or decrease salivary cortisol levels in healthy older adults. Fifteen adults participated and were randomly assigned to a RR training or control groups. Mean age was 71.3 years and mean education level was 17.9 years. Reaction time on a simple attention/psychomotor task was significantly improved (p<0.0025) with RR training, whereas there was no significant improvement on complex tasks of attention, verbal, or visual declarative memory tests. Self-reported state anxiety levels showed a marginally significant reduction (p<0.066). All subjects' salivary cortisol levels were within low-normal range and did not significantly change. Our 5-week program in highly educated, mobile, healthy, aging adults significantly improved performance on a simple attention task.

Systemic effects of AGEs in ER stress induction in vivo.

PubMed

Adamopoulos, Christos; Mihailidou, Chrysovalantou; Grivaki, Christofora; Papavassiliou, Kostas A; Kiaris, Hippokratis; Piperi, Christina; Papavassiliou, Athanasios G

2016-08-01

Emerging evidence indicates that accumulation of advanced glycation end products (AGEs) in human tissues may contribute to cell injury, inflammation and apoptosis through induction of endoplasmic reticulum (ER) stress. Human metabolism relies on ER homeostasis for the coordinated response of all metabolic organs by controlling the synthesis and catabolism of various nutrients. In vitro studies have demonstrated AGE-induced enhancement of unfolded protein response (UPR) in different cell types including endothelial, neuronal, pancreatic cells and podocytes, suggesting this crosstalk as an underlying pathological mechanism that contributes to metabolic diseases. In this minireview, we describe in vivo studies undertaken by our group and others that demonstrate the diverse systemic effects of AGEs in ER stress induction in major metabolic tissues such as brain, kidney, liver and pancreas of normal mice. Administration of high-AGEs content diet to normal mice for the period of 4 weeks upergulates the mRNA and protein levels of ER chaperone Bip (GRP78) indicative of UPR initiation in all major metabolic organs and induces activation of the pivotal transcription factor XBP1 that regulates glucose and lipid metabolism. Furthermore, animals with genetic ablation of UPR-activated transcription factor C/EBP homologous protein CHOP allocated in high-AGEs diet, exhibited relative resistance to UPR induction (BiP levels) and XBP1 activation in major metabolic organs. Since CHOP presents a critical mediator that links accumulation and aggregation of unfolded proteins with induction of oxidative stress and ER stress-related apoptosis, it is revealed as an important molecular target for the management of metabolic diseases.

Nonlinear dynamics applied to the study of cardiovascular effects of stress

NASA Astrophysics Data System (ADS)

Anishchenko, T. G.; Igosheva, N. B.

1998-03-01

We study cardiovascular responses to emotional stresses in humans and rats using traditional physiological parameters and methods of nonlinear dynamics. We found that emotional stress results in significant changes of chaos degree of ECG and blood pressure signals, estimated using a normalized entropy. We demonstrate that the normalized entropy is a more sensitive indicator of the stress-induced changes in cardiovascular systems compared with traditional physiological parameters Using the normalized entropy we discovered the significant individual differences in cardiovascular stress-reactivity that was impossible to obtain by traditional physiological methods.

A simple model for the prediction of the discrete stiffness states of a homogeneous electrostatically tunable multi-layer beam

NASA Astrophysics Data System (ADS)

Bergamini, A.; Christen, R.; Motavalli, M.

2007-04-01

The adaptive modification of the mechanical properties of structures has been described as a key to a number of new or enhanced technologies, ranging from prosthetics to aerospace applications. Previous work reported the electrostatic tuning of the bending stiffness of simple sandwich structures by modifying the shear stress transfer parameters at the interface between faces and the compliant core of the sandwich. For this purpose, the choice of a sandwich structure presented considerable experimental advantages, such as the ability to obtain a large increase in stiffness by activating just two interfaces between the faces and the core of the beam. The hypothesis the development of structures with tunable bending stiffness is based on, is that by applying a normal stress at the interface between two layers of a multi-layer structure it is possible to transfer shear stresses from one layer to the other by means of adhesion or friction forces. The normal stresses needed to generate adhesion or friction can be generated by an electrostatic field across a dielectric layer interposed between the layers of a structure. The shear stress in the cross section of the structure (e.g. a beam) subjected to bending forces is transferred in full, if sufficiently large normal stresses and an adequate friction coefficient at the interface are given. Considering beams with a homogeneous cross-section, in which all layers are made of the same material and have the same width, eliminates the need to consider parameters such as the shear modulus of the material and the shear stiffness of the core, thus making the modelling work easier and the results more readily understood. The goal of the present work is to describe a numerical model of a homogeneous multi-layer beam. The model is validated against analytical solutions for the extreme cases of interaction at the interface (no friction and a high level of friction allowing for full shear stress transfer). The obtained model is used to better understand the processes taking place at the interfaces between layers, demonstrate the existence of discrete stiffness states and to find guidance for the selection of suitable dielectric layers for the generation of the electrostatic normal stresses needed for the shear stress transfer at the interface.

Tidal triggering of low frequency earthquakes near Parkfield, California: Implications for fault mechanics within the brittle-ductile transition

USGS Publications Warehouse

Thomas, A.M.; Burgmann, R.; Shelly, David R.; Beeler, Nicholas M.; Rudolph, M.L.

2012-01-01

Studies of nonvolcanic tremor (NVT) have established the significant impact of small stress perturbations on NVT generation. Here we analyze the influence of the solid earth and ocean tides on a catalog of ∼550,000 low frequency earthquakes (LFEs) distributed along a 150 km section of the San Andreas Fault centered at Parkfield. LFE families are identified in the NVT data on the basis of waveform similarity and are thought to represent small, effectively co-located earthquakes occurring on brittle asperities on an otherwise aseismic fault at depths of 16 to 30 km. We calculate the sensitivity of each of these 88 LFE families to the tidally induced right-lateral shear stress (RLSS), fault-normal stress (FNS), and their time derivatives and use the hypocentral locations of each family to map the spatial variability of this sensitivity. LFE occurrence is most strongly modulated by fluctuations in shear stress, with the majority of families demonstrating a correlation with RLSS at the 99% confidence level or above. Producing the observed LFE rate modulation in response to shear stress perturbations requires low effective stress in the LFE source region. There are substantial lateral and vertical variations in tidal shear stress sensitivity, which we interpret to reflect spatial variation in source region properties, such as friction and pore fluid pressure. Additionally, we find that highly episodic, shallow LFE families are generally less correlated with tidal stresses than their deeper, continuously active counterparts. The majority of families have weaker or insignificant correlation with positive (tensile) FNS. Two groups of families demonstrate a stronger correlation with fault-normal tension to the north and with compression to the south of Parkfield. The families that correlate with fault-normal clamping coincide with a releasing right bend in the surface fault trace and the LFE locations, suggesting that the San Andreas remains localized and contiguous down to near the base of the crust. The deep families that have high sensitivity to both shear and tensile normal stress perturbations may be indicative of an increase in effective fault contact area with depth. Synthesizing our observations with those of other LFE-hosting localities will help to develop a comprehensive understanding of transient fault slip below the “seismogenic zone” by providing constraints on parameters in physical models of slow slip and LFEs.

Leptin downregulates heat shock protein-70 (HSP-70) gene expression in chicken liver and hypothalamus.

PubMed

Figueiredo, Denise; Gertler, Arieh; Cabello, Gérard; Decuypere, Eddy; Buyse, Johan; Dridi, Sami

2007-07-01

Heat shock protein (HSP)-70 is expressed in normal and stressed cells but is highly stress-inducible. Although leptin has long been suggested to be involved in the regulation of stress response, its interaction with the HSP-70 gene is still unknown, under both unstressed and stressed conditions. The present study has aimed to investigate the effect of leptin on HSP-70 gene expression in normal chicken liver, hypothalamus, and muscle. Continuous infusion of recombinant chicken leptin (8 mug/kg per hour) at a constant rate of 3 ml/h for 6 h in 3-week-old broiler chickens significantly (P < 0.05) decreased food intake and HSP-70 mRNA levels in liver and hypothalamus, but not in muscle. In an attempt to discriminate between the effect of leptin and of leptin-reduced food intake on HSP-70 gene expression, we also evaluated the effect of food deprivation on the same cellular responses in two broiler chicken lines genetically selected for low (LL) or high (FL) abdominal fat pad size. Food deprivation for 16 h did not affect HSP-70 gene expression in any of the studied tissues indicating that the effect of leptin was independent of the inhibition of food intake. Regardless of the nutritional status, HSP-70 mRNA levels were significantly (P < 0.05) higher in the hypothalamus of FL compared with LL chickens consistent with higher mRNA levels for hypothalamic corticotropin-releasing factor. To assess, whether the effects of leptin were direct or indirect, we carried out in vitro studies. Leptin treatments did not affect HSP-70 mRNA levels in a leghorn male hepatoma cell line or quail myoblast cell line suggesting that the effect of leptin on HSP-70 gene expression is mediated through the central nervous system. Furthermore, HSP-70 gene expression was gender-dependent with significantly (P < 0.05) higher levels in male than in female chickens.

Dorsal aorta catheterization in rainbow trout (Salmo gairdneri) I. Its validity in the study of blood gonadotropin patterns.

PubMed

Zohar, Y

1980-01-01

The use of a dorsal aorta catheterization technique to study gonadotropin secretion patterns in the rainbow trout was tested. Heparin used to flush the cannula between repetitive samplings did not have any effect on plasma GTH levels. Catheterization resulted in a slight short-term change in those levels. The gonadotropin levels returned to their initial values as soon as 30 min to 6 hrs after the operation. From then on, the GTH levels remained close to the initial values in fish exhibiting normal feeding behaviour, whereas they tended to decrease in "stressed" females which did not eat normally. The fish which adapted well to dorsal aortic catheterization did not show any changes in the diurnal pattern of GTH levels or in normal gonadal function and GTH profiles during the processes of oocyte maturation and ovulation. It is concluded that individual catheterized trout can be used advantageously for studying gonadotropin secretion patterns after a 3-day recovery period and the elimination of those fish which neither resume normal feeding nor return to initial, pre-operative GTH levels. Using this technique, it was demonstrated that hypophysial GTH release in trout with oocytes undergoing active vitellogenesis is probably effected by short-term bursts (pulses) of secretion.

Beneficial effects of benzodiazepine diazepam on chronic stress-induced impairment of hippocampal structural plasticity and depression-like behavior in mice.

PubMed

Zhao, Yunan; Wang, Zhongli; Dai, Jianguo; Chen, Lin; Huang, Yufang; Zhan, Zhen

2012-03-17

Whether benzodiazepines (BZDs) have beneficial effects on the progress of chronic stress-induced impairment of hippocampal structural plasticity and major depression is uncertain. The present study designed four preclinical experiments to determine the effects of BZDs using chronic unpredictable stress model. In Experiment 1, several time course studies on behavior and hippocampus response to stress were conducted using the forced swim and tail suspension tests (FST and TST) as well as hippocampal structural plasticity markers. Chronic stress induced depression-like behavior in the FST and TST as well as decreased hippocampal structural plasticity that returned to normal within 3 wk. In Experiment 2, mice received p.o. administration of three diazepam dosages prior to each variate stress session for 4 wk. This treatment significantly antagonized the elevation of stress-induced corticosterone levels. Only low- (0.5mg/kg) and medium-dose (1mg/kg) diazepam blocked the detrimental effects of chronic stress. In Experiment 3, after 7 wk of stress sessions, daily p.o. diazepam administration during 1 wk recovery phase dose-dependently accelerated the recovery of stressed mice. In Experiment 4, 1 wk diazepam administration to control mice enhanced significantly hippocampal structural plasticity and induced an antidepressant-like behavioral effect, whereas 4 wk diazepam administration produced opposite effects. Hence, diazepam can slow the progress of chronic stress-induced detrimental consequences by normalizing glucocorticoid hormones. Considering the adverse effect of long-term diazepam administration on hippocampal plasticity, the preventive effects of diazepam may depend on the proper dose. Short-term diazepam treatment enhances hippocampal structural plasticity and is beneficial to recovery following chronic stress. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of berberine on the growth and immune performance in response to ammonia stress and high-fat dietary in blunt snout bream Megalobrama amblycephala.

PubMed

Chen, Qing-Qing; Liu, Wen-Bin; Zhou, Man; Dai, Yong-Jun; Xu, Chao; Tian, Hong-Yan; Xu, Wei-Na

2016-08-01

This study aimed to figure out the effects of berberine on growth performance, immunity, oxidative stress and hepatocyte apoptosis of blunt snout bream (Megalobrama amblycephala) fed with high-fat diet. 320 fish (80.00 ± 0.90 g) were divided randomly into four trial groups (each with four replicates) and fed with 4 diets (normal diet, normal diet with 50 mg/kg berberine, high-fat diet, high-fat diet with 50 mg/kg berberine), respectively. At the end of the feeding trial, ammonia stress test was carried out for 5 days. The result showed the growth performance, immune parameters including plasm acid phosphatase (ACP) activities, lysozyme (LYZ) activities and alternative complement C3 and C4 contents were suppressed in fish fed with high-fat diets but improved in berberine diets compared with control (normal diet). Hepatopancreas oxidative status, the malondialdehyde (MDA), protein carbonyl (PC) and lipid peroxide (LPO) were increased significantly (P < 0.05) when fish were fed with high-fat diets. Berberine could slow the progression of the oxidative stress induced by high-fat through increasing superoxide dismutase (SOD) activities and total sulfydryl (T-SH) levels of fish. And the hepatocyte apoptosis in the high-fat group could also be alleviated by berberine. After the ammonia stress test, the accumulative mortality was extremely (P < 0.05) low in fish fed high-fat diet with berberine compared to other groups. It was concluded berberine as a functional feed additive significantly inhibited the progression of oxidative stress, reduced the apoptosis and enhanced the immunity of fish fed with high-fat diet. Copyright © 2016 Elsevier Ltd. All rights reserved.

CD47 Receptor Globally Regulates Metabolic Pathways That Control Resistance to Ionizing Radiation*

PubMed Central

Miller, Thomas W.; Soto-Pantoja, David R.; Schwartz, Anthony L.; Sipes, John M.; DeGraff, William G.; Ridnour, Lisa A.; Wink, David A.; Roberts, David D.

2015-01-01

Modulating tissue responses to stress is an important therapeutic objective. Oxidative and genotoxic stresses caused by ionizing radiation are detrimental to healthy tissues but beneficial for treatment of cancer. CD47 is a signaling receptor for thrombospondin-1 and an attractive therapeutic target because blocking CD47 signaling protects normal tissues while sensitizing tumors to ionizing radiation. Here we utilized a metabolomic approach to define molecular mechanisms underlying this radioprotective activity. CD47-deficient cells and cd47-null mice exhibited global advantages in preserving metabolite levels after irradiation. Metabolic pathways required for controlling oxidative stress and mediating DNA repair were enhanced. Some cellular energetics pathways differed basally in CD47-deficient cells, and the global declines in the glycolytic and tricarboxylic acid cycle metabolites characteristic of normal cell and tissue responses to irradiation were prevented in the absence of CD47. Thus, CD47 mediates signaling from the extracellular matrix that coordinately regulates basal metabolism and cytoprotective responses to radiation injury. PMID:26311851

Ulcerative Dermatitis in C57BL/6 Mice Exhibits an Oxidative Stress Response Consistent with Normal Wound Healing

PubMed Central

Williams, Lisa K; Csaki, Lauren S; Cantor, Rita M; Reue, Karen; Lawson, Greg W

2012-01-01

Ulcerative dermatitis (UD) is a common syndrome of unknown etiology that results in profound morbidity in C57BL/6 mice and lines on a C57BL/6 background. The lesions are due to severe pruritus-induced self-trauma, progressing from superficial excoriations to deep ulcerations. UD may be behavioral in origin, with ulcerative lesions resulting from self-mutilating behavior in response to unresolved inflammation or compulsion. Alternatively, abnormal oxidative damage may be a mechanism underlying UD. To evaluate whether UD behaves similarly to normal wounds, consistent with a secondary self-inflicted lesion, or is a distinct disorder with abnormal wound response, we evaluated expression levels of genes representing various arms of the oxidative stress response pathway UD-affected and unwounded C57BL/6J mice. No evidence indicated that UD wounds have a defect in the oxidative stress response. Our findings are consistent with an understanding of C57BL/6 UD lesions as typical rather than atypical wounds. PMID:22776048

Variability of Slip Behavior in Simulations of Dynamic Rupture Interaction With Stronger Fault Patches Over Long-Term Deformation Histories

NASA Astrophysics Data System (ADS)

Lapusta, N.; Liu, Y.

2007-12-01

Heterogeneity in fault properties can have significant effect on dynamic rupture propagation and aseismic slip. It is often assumed that a fixed heterogeneity would have similar effect on fault slip throughout the slip history. We investigate dynamic rupture interaction with a fault patch of higher normal stress over several earthquake cycles in a three-dimensional model. We find that the influence of the heterogeneity on dynamic events has significant variation and depends on prior slip history. We consider a planar strike-slip fault governed by rate and state friction and driven by slow tectonic loading on deeper extension of the fault. The 30 km by 12 km velocity-weakening region, which is potentially seismogenic, is surrounded by steady-state velocity-strengthening region. The normal stress is constant over the fault, except in a circular patch of 2 km in diameter located in the seismogenic region, where normal stress is higher than on the rest of the fault. Our simulations employ the methodology developed by Lapusta and Liu (AGU, 2006), which is able to resolve both dynamic and quasi-static stages of spontaneous slip accumulation in a single computational procedure. The initial shear stress is constant on the fault, except in a small area where it is higher and where the first large dynamic event initiates. For patches with 20%, 40%, 60% higher normal stress, the first event has significant dynamic interaction with the patch, creating a rupture speed decrease followed by a supershear burst and larger slip around the patch. Hence, in the first event, the patch acts as a seismic asperity. For the case of 100% higher stress, the rupture is not able to break the patch in the first event. In subsequent dynamic events, the behavior depends on the strength of heterogeneity. For the patch with 20% higher normal stress, dynamic rupture in subsequent events propagates through the patch without any noticeable perturbation in rupture speed or slip. In particular, supershear propagation and additional slip accumulation around the patch are never repeated in the simulated history of the fault, and the patch stops manifesting itself as a seismic asperity. This is due to higher shear stress that is established at the patch after the first earthquake cycle. For patches with higher normal stress, shear stress redistribution also occurs, but it is less effective. The patches with 40% and 60% higher normal stress continue to affect rupture speed and fault slip in some of subsequent events, although the effect is much diminished with respect to the first event. For example, there are no supershear bursts. The patch with 100% higher normal stress is first broken in the second large event, and it retains significant influence on rupture speed and slip throughout the fault history, occasionally resulting in supershear bursts. Additional slip complexity emerges for patches with 40% and higher normal stress contrast. Since higher normal stress corresponds to a smaller nucleation size, nucleation of some events moves from the rheological transitions (where nucleation occurs in the cases with no stronger patch and with the patch of 20% higher normal stress) to the patches of higher normal stress. The patches nucleate both large, model-spanning, events, and small events that arrest soon after exiting the patch. Hence not every event that originates at the location of a potential seismic asperity is destined to be large, as its subsequent propagation is significantly influenced by the state of stress outside the patch.

The stress protein level under clinorotation in context of the seedling developmental program and the stress response

NASA Astrophysics Data System (ADS)

Kozeko, Lyudmyla; Kordyum, Elizabeth

2006-09-01

Heat-shock proteins (HSP70 and HSP90) are present in plant cells under the normal growth conditions. At the same time, a variety of environmental disruptions results in their rapid synthesis as a substantial part of adaptation. HSP amounts can be indicative of a cellular stress level. Altered gravity (clinorotation) is unnatural for plants, so it may be a kind of stress. The aim of this study was to analyze the influence of horizontal clinorotation on the HSP70 and HSP90 level during seedling development. Pea (Pisum sativum L.) seedlings grown for 3 days from seed imbibitions in stationary control and under slow clinorotation (2 rpm) are used for this investigation. Western blot analysis indicated that HSP70 and HSP90 were abundant in the embryos of dry seeds and their amount decreased significantly during seed germination. But under horizontal clinorotation, their level in seedlings remained higher compared to the control. Furthermore, a comparison of the influence of horizontal and vertical clinorotation on the HSP level was carried out. On the ELISA data, HSP70 and HSP90 amounts in the 3-day old seedlings were higher after horizontal clinorotation than after vertical. The obtained data show an increased HSP70 and HSP90 level in pea seedlings under clinorotation. Both, rotation and change in the cell position relatively to a gravity vector affect the HSP level.

Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

NASA Astrophysics Data System (ADS)

Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

2017-03-01

The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

Normalization for Relative Quantification of mRNA and microRNA in Soybean Exposed to Various Abiotic Stresses

PubMed Central

Zhou, Yonggang; Chen, Huan; Dong, Yuanyuan; Wang, Nan; Li, Xiaowei; Jameel, Aysha; Yang, He; Zhang, Min; Chen, Kai; Wang, Fawei; Li, Haiyan

2016-01-01

Plant microRNAs are small non-coding, endogenic RNA molecule (containing 20–24 nucleotides) produced from miRNA precursors (pri-miRNA and pre-miRNA). Evidence suggests that up and down regulation of the miRNA targets the mRNA genes involved in resistance against biotic and abiotic stresses. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is a powerful technique to analyze variations in mRNA levels. Normalizing the data using reference genes is essential for the analysis of reliable RT-qPCR data. In this study, two groups of candidate reference mRNAs and miRNAs in soybean leaves and roots treated with various abiotic stresses (PEG-simulated drought, salinity, alkalinity, salinity+alkalinity, and abscisic acid) were analyzed by RT-qPCR. We analyzed the most appropriate reference mRNA/miRNAs using the geNorm, NormFinder, and BestKeeper algorithms. According to the results, Act and EF1b were the most suitable reference mRNAs in leaf and root samples, for mRNA and miRNA precursor data normalization. The most suitable reference miRNAs found in leaf and root samples were 166a and 167a for mature miRNA data normalization. Hence the best combinations of reference mRNAs for mRNA and miRNA precursor data normalization were EF1a + Act or EF1b + Act in leaf samples, and EF1a + EF1b or 60s + EF1b in root samples. For mature miRNA data normalization, the most suitable combinations of reference miRNAs were 166a + 167d in leaf samples, and 171a + 156a or 167a + 171a in root samples. We identified potential reference mRNA/miRNAs for accurate RT-qPCR data normalization for mature miRNA, miRNA precursors, and their targeted mRNAs. Our results promote miRNA-based studies on soybean plants exposed to abiotic stress conditions. PMID:27176476

Effects of snake venom from Saudi cobras and vipers on hormonal levels in peripheral blood.

PubMed

Abdel-Galil, Khidir A; Al-Hazimi, Awdah M

2004-08-01

Knowledge about the effects of snake venoms on endocrine glands in the Kingdom of Saudi Arabia (KSA) is meager. The aim of the present study is to investigate the acute and chronic envenomation from 4 snakes out of 8 species of Saudi Cobras and Vipers on the tissues of endocrine glands and peripheral hormonal levels in male rats. The peripheral blood levels of 4 hormones mainly testosterone, cortisol, insulin and thyroxin were investigated in male Wistar rats following acute and chronic treatment of the rats with poisonous snake venoms at the Department of Physiology, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia between September 2000 to May 2001. Using radio immunoassay for hormonal analysis, a rise in testosterone levels in peripheral blood was obtained following acute treatment, which is due to the effect of the venoms on vascular permeability and increased blood flow. In contrast, the chronic treatment with venoms resulted in a delayed effect on vascular permeability and testicular degeneration resulting in a decreased blood flow and a significant drop in testosterone concentration. Cortisol levels were no different from the controls during acute treatment but it demonstrates gradual rise following chronic treatment to withstand the stress imposed on the animals. Similar results were obtained for insulin, which showed normal values with acute treatment but decreased levels of chronic treatment suggesting insulin insufficiently. Likewise, the thyroxin levels were decreased with chronic treatment suggesting a toxic effect of the poison on the rich blood supply of the thyroid follicles with a subsequent decrease in blood flow to the tissues and therefore, decreased thyroid hormone levels. The effects of venom toxicity on testosterone levels were either normal or stimulatory with acute treatment or inhibitory with chronic treatment depending on the vascular blood flow and testicular degeneration. Cortisol levels were normal at acute treatment but showed a gradual rise reflecting the stress imposed on the animals. The rise in cortisol levels was visualized to potentiate the cardiovascular and metabolic changes. The effects on insulin and thyroxin were similar to those of testosterone level showing normal or stimulatory effect with acute treatment followed by decreased levels of hormones with chronic treatment.

Personality dimensions in bulimia nervosa, binge eating disorder, and obesity.

PubMed

Peterson, Carol B; Thuras, Paul; Ackard, Diann M; Mitchell, James E; Berg, Kelly; Sandager, Nora; Wonderlich, Stephen A; Pederson, Melissa W; Crow, Scott J

2010-01-01

The purpose of this investigation was to examine differences in personality dimensions among individuals with bulimia nervosa, binge eating disorder, non-binge eating obesity, and a normal-weight comparison group as well as to determine the extent to which these differences were independent of self-reported depressive symptoms. Personality dimensions were assessed using the Multidimensional Personality Questionnaire in 36 patients with bulimia nervosa, 54 patients with binge eating disorder, 30 obese individuals who did not binge eat, and 77 normal-weight comparison participants. Participants with bulimia nervosa reported higher scores on measures of stress reaction and negative emotionality compared to the other 3 groups and lower well-being scores compared to the normal-weight comparison and the obese samples. Patients with binge eating disorder scored lower on well-being and higher on harm avoidance than the normal-weight comparison group. In addition, the bulimia nervosa and binge eating disorder groups scored lower than the normal-weight group on positive emotionality. When personality dimensions were reanalyzed using depression as a covariate, only stress reaction remained higher in the bulimia nervosa group compared to the other 3 groups and harm avoidance remained higher in the binge eating disorder than the normal-weight comparison group. The higher levels of stress reaction in the bulimia nervosa sample and harm avoidance in the binge eating disorder sample after controlling for depression indicate that these personality dimensions are potentially important in the etiology, maintenance, and treatment of these eating disorders. Although the extent to which observed group differences in well-being, positive emotionality, and negative emotionality reflect personality traits, mood disorders, or both, is unclear, these features clearly warrant further examination in understanding and treating bulimia nervosa and binge eating disorder.

Cerebrospinal Fluid Concentration of Key Autophagy Protein Lamp2 Changes Little During Normal Aging

PubMed Central

Loeffler, David A.; Klaver, Andrea C.; Coffey, Mary P.; Aasly, Jan O.

2018-01-01

Autophagy removes both functional and damaged intracellular macromolecules from cells via lysosomal degradation. Three autophagic mechanisms, namely macroautophagy, chaperone-mediated autophagy (CMA), and microautophagy, have been described in mammals. Studies in experimental systems have found macroautophagy and CMA to decrease with normal aging, despite the fact that oxidative stress, which can activate both processes, increases with normal aging. Whether autophagic mechanisms decrease in the human brain during normal aging is unclear. The primary objective of this study was to examine the association of a major autophagy protein, lysosome-associated membrane glycoprotein (lamp2), with age in cerebrospinal fluid (CSF) samples from healthy subjects. Lamp2 consists of three isoforms, lamp2a, 2b and 2c, all of which participate in autophagy. Lamp2’s CSF concentration decreases in Parkinson’s disease (PD) and increases in Alzheimer’s disease (AD), but whether its CSF concentration changes during normal aging has not been investigated. Our secondary objectives were to examine the associations of lamp2’s CSF concentration with CSF levels of the molecular chaperone heat shock 70-kDa protein (HSPA8), which interacts with lamp2a in CMA, and oxidative stress markers 8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-isoprostane (8-ISO) and Total Antioxidant Capacity (TAC) in healthy subjects. We found lamp2’s observed associations with these variables to be weak, with all Kendall’s tau-b absolute values ≤0.20. These results suggest that CSF lamp2 concentration changes little during normal aging and does not appear to be associated with HSPA8 or oxidative stress. Further studies are indicated to determine the relationship between CSF lamp2 concentration and brain autophagic processes.

Performance Under Stress Conditions During Multidisciplinary Team Immersive Pediatric Simulations.

PubMed

Ghazali, Daniel Aiham; Darmian-Rafei, Ivan; Ragot, Stéphanie; Oriot, Denis

2018-06-01

The primary objective was to determine whether technical and nontechnical performances were in some way correlated during immersive simulation. Performance was measured among French Emergency Medical Service workers at an individual and a team level. Secondary objectives were to assess stress response through collection of physiologic markers (salivary cortisol, heart rate, the proportion derived by dividing the number of interval differences of successive normal-to-normal intervals > 50 ms by the total number of normal-to-normal intervals [pNN50], low- and high-frequency ratio) and affective data (self-reported stress, confidence, and dissatisfaction), and to correlate them to performance scores. Prospective observational study performed as part of a larger randomized controlled trial. Medical simulation laboratory. Forty-eight participants distributed among 12 Emergency Medical System teams. Individual and team performance measures and individual stress response were assessed during a high-fidelity simulation. Technical performance was assessed by the intraosseous access performance scale and the Team Average Performance Assessment Scale; nontechnical performance by the Behavioral Assessment Tool for leaders, and the Clinical Teamwork Scale. Stress markers (salivary cortisol, heart rate, pNN50, low- and high-frequency ratio) were measured both before (T1) and after the session (T2). Participants self-reported stress before and during the simulation, self-confidence, and perception of dissatisfaction with team performance, rated on a scale from 0 to 10. Scores (out of 100 total points, mean ± SD) were intraosseous equals to 65.6 ± 14.4, Team Average Performance Assessment Scale equals to 44.6 ± 18.1, Behavioral Assessment Tool equals to 49.5 ± 22.0, Clinical Teamwork Scale equals to 50.3 ± 18.5. There was a strong correlation between Behavioral Assessment Tool and Clinical Teamwork Scale (Rho = 0.97; p = 0.001), and Behavioral Assessment Tool and Team Average Performance Assessment Scale (Rho = 0.73; p = 0.02). From T1 to T2, all stress markers (salivary cortisol, heart rate, pNN50, and low- and high-frequency ratio) displayed an increase in stress level (p < 0.001 for all). Self-confidence was positively correlated with performance (Clinical Teamwork Scale: Rho = 0.47; p = 0.001, Team Average Performance Assessment Scale: Rho = 0.46; p = 0.001). Dissatisfaction was negatively correlated with performance (Rho = -0.49; p = 0.0008 with Behavioral Assessment Tool, Rho = -0.47; p = 0.001 with Clinical Teamwork Scale, Rho = -0.51; p = 0.0004 with Team Average Performance Assessment Scale). No correlation between stress response and performance was found. There was a positive correlation between leader (Behavioral Assessment Tool) and team (Clinical Teamwork Scale and Team Average Performance Assessment Scale) performances. These performance scores were positively correlated with self-confidence and negatively correlated with dissatisfaction.

The Influence of Artificial Cervical Disc Prosthesis Height on the Cervical Biomechanics: A Finite Element Study.

PubMed

Yuan, Wei; Zhang, Haiping; Zhou, Xiaoshu; Wu, Weidong; Zhu, Yue

2018-05-01

Artificial cervical disc replacement is expected to maintain normal cervical biomechanics. At present, the effect of the Prestige LP prosthesis height on cervical biomechanics has not been thoroughly studied. This finite element study of the cervical biomechanics aims to predict how the parameters, like range of motion (ROM), adjacent intradiscal pressure, facet joint force, and bone-implant interface stress, are affected by different heights of Prestige LP prostheses. The finite element model of intact cervical spine (C3-C7) was obtained from our previous study, and the model was altered to implant Prestige LP prostheses at the C5-C6 level. The effects of the height of 5, 6, and 7 mm prosthesis replacement on ROM, adjacent intradiscal pressure, facet joint force, as well as the distribution of bone-implant interface stress were examined. ROM, adjacent intradiscal pressure, and facet joint force increased with the prosthesis height, whereas ROM and facet joint force decreased at C5-C6. The maximal stress on the inferior surface of the prostheses was greater than that on the superior surface, and the stresses increased with the prosthesis height. The biomechanical changes were slightly affected by the height of 5 and 6 mm prostheses, but were strongly affected by the 7-mm prosthesis. An appropriate height of the Prestige LP prosthesis can preserve normal ROM, adjacent intradiscal pressure, and facet joint force. Prostheses with a height of ≥2 mm than normal can lead to marked changes in the cervical biomechanics and bone-implant interface stress. Copyright © 2018 Elsevier Inc. All rights reserved.

Enhancement of allergic skin wheal responses in patients with atopic eczema/dermatitis syndrome by playing video games or by a frequently ringing mobile phone.

PubMed

Kimata, H

2003-06-01

Playing video games causes physical and psychological stress, including increased heart rate and blood pressure and aggression-related feelings. Use of mobile phones is very popular in Japan, and frequent ringing is a common and intrusive part of Japanese life. Atopic eczema/dermatitis syndrome is often exacerbated by stress. Stress increases serum IgE levels, skews cytokine pattern towards Th2 type, enhances allergen-induced skin wheal responses, and triggers mast cell degranulation via substance P, vasoactive intestinal peptide and nerve growth factor. (1). In the video game study, normal subjects (n = 25), patients with allergic rhinitis (n = 25) or atopic eczema/dermatitis syndrome (n = 25) played a video game (STREET FIGHTER II) for 2 h. Before and after the study, allergen-induced wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factor, and in vitro production of total IgE, antihouse dust mite IgE and cytokines were measured. (2). In the mobile phone study, normal subjects (n = 27), patients with allergic rhinitis (n = 27) or atopic eczema/dermatitis syndrome (n = 27) were exposed to 30 incidences of ringing mobile phones during 30 min. Before and after the study, allergen-induced wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factor were measured. Playing video games had no effect on the normal subjects or the patients with allergic rhinitis. In contrast, playing video games significantly enhanced allergen-induced skin wheal responses and increased plasma levels of substance P, vasoactive intestinal peptide and nerve growth factors in the patients with atopic eczema/dermatitis syndrome. Moreover, playing video games enhanced in vitro production of total IgE and anti-house dust mite IgE with concomitant increased production of IL-4, IL-10 and IL-13 and decreased production of IFN-gamma and IL-12 in the patients with atopic eczema/dermatitis syndrome. However, exposure to frequently ringing mobile phones significantly enhanced allergen-induced skin wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factors in the patients with atopic eczema/dermatitis syndrome, but not in the normal subjects or the patients with allergic rhinitis. Playing video games enhanced allergic responses with a concomitant increased release of substance P, vasoactive intestinal peptide and nerve growth factor, and skewing of the cytokine pattern toward Th2 type in the patients with atopic eczema/dermatitis syndrome. In addition, exposure to frequently ringing mobile phones also enhanced allergic responses with a concomitant increased release of substance P, vasoactive intestinal peptide and nerve growth factor Collectively, high technology causes stress, which in turn may aggravate symptoms of atopic eczema/dermatitis syndrome.

In utero glucocorticoid (GLC) exposure reduces fetal skeletal muscle growth in rats

USDA-ARS?s Scientific Manuscript database

Maternal undernutrition and stress expose the fetus to above normal levels of GLC and predispose to intrauterine growth restriction. The aim of this study was to determine if fetal GLC exposure impairs skeletal muscle growth independently of maternal undernutrition. Three groups (n=7/group) of timed...

Exercise, Animal Aerobics, and Interpretation?

ERIC Educational Resources Information Center

Oliver, Valerie

1996-01-01

Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

Role stress among auxiliary nurses midwives in Gujarat, India.

PubMed

Purohit, Bhaskar; Vasava, Paul

2017-01-23

Understanding Role Stress is important as health service providers, especially nurses experience high levels of Role Stress which is linked to burnout, poor quality of care and high turnover. The current study explicates the concept of Role Stress and assesses the Role Stress experienced by the Auxiliary Nurse Midwives (ANMs) working with rural government health centres from Gujarat, India. The study included 84 ANMs working with government health centres from one district in India. A structured instrument with established reliability and validity was used to measure 10 dimensions of Role Stress namely: Inter-role distance, role stagnation, role expectation conflict, role erosion: role overload, role isolation, personal inadequacy, self-role distance, role ambiguity and resource inadequacy. The study instrument was based on 5 point Likert rating scale that contained 50 unidirectional negative statements, 5 for each dimension. Kolmogorov-Smirnov and Shapiro-Wilk test were carried out to assess if the data were normally distributed. Cronbach's alpha test was carried out to assess reliability of the instrument. The study data was analyzed using descriptive statistics mainly using mean scores with higher scores indicating higher Role Stress and vice versa. The data was analyzed using SPSS version 19. Kolmogorov-Smirnov and Shapiro-Wilk test indicated that the data were normally distributed. Cronbach's alpha test indicated values of 0.852 suggesting high reliability of the tool. The highest Role Stress among ANMs was experienced for resource inadequacy. Role overload, role stagnation and inter-role distance were among the other important role stressors for ANMs. The study results suggests that ANMs frequently feel that: they do not have adequate amount of resources, facilities and financial support from the high levels authorities; people have too many expectations from their roles and as result they are overloaded with work and have very limited opportunities for future growth. The current study has the potential to provide a useful and a comprehensive framework to understand the Role Stress among the health service providers that could be further useful in designing interventions specifically aimed at reducing Role Stress in order to prevent burnout thereby addressing the productivity and retention.

Anti-stress effects of cilnidipine and nimodipine in immobilization subjected mice.

PubMed

Kumar, Naresh; Singh, Nirmal; Jaggi, Amteshwar Singh

2012-03-20

The present study was designed to investigate the ameliorative role of cilnidipine and nimodipine in immobilization stress-induced behavioral alterations and memory defects in the mice. Acute stress was induced by immobilizing the mice for 150 min and stress-induced behavioral changes were assessed using actophotometer, hole board, open field and social interaction tests. The learning and memory was evaluated using elevated plus maze tests and biochemically, the corticosterone levels were measured in the blood serum. Acute immobilization stress resulted in decrease in locomotor activity, frequency of head dips and rearings in hole board; line crossing and rearing in the open field; increase in avoidance in social behavior along with development of memory deficits assessed by an increased transfer latency time and elevation of the corticosterone levels. Administration of cilnidipine (10 mg/kg), an L and N-type dual calcium channel blocker, and nimodipine (10 mg/kg), an L-type calcium channel blocker, significantly attenuated the immobilized stress-induced behavioral changes and restored memory deficits along with normalization of the corticosterone levels. Cilnidipine and nimodipine produced comparable beneficial effects in restoring immobilization stress subjected mice. It may be concluded that cilnidipine and nimodipine mediated attenuation of corticosterone release by blockage of calcium channels (both L and N-type) on the HPA-axis is responsible for beneficial effects in restoration of behavioral alterations and memory deficits in immobilization-induced acute stress in mice. Copyright © 2011 Elsevier Inc. All rights reserved.

Psychological Health and Overweight and Obesity Among High Stressed Work Environments

PubMed Central

Faghri, Pouran D; Mignano, Christina; Huedo- Medina, Tania B; Cherniack, Martin

2016-01-01

Correctional employees are recognized to underreport stress and stress symptoms and are known to have a culture that discourages appearing “weak” and seeking psychiatric help. This study assesses underreporting of stress and emotions. Additionally, it evaluates the relationships between stress and emotions on health behaviors. Correctional employees (n=317) completed physical assessments to measure body mass index (BMI), and surveys to assess perceived stress, emotions, and health behavior (diet, exercise, and sleep quality). Stress and emotion survey items were evaluated for under-reporting via skewness, kurtosis, and visual assessment of histograms. Structural equation modeling evaluated relationships between stress/emotion and health behaviors. Responses to stress and negatively worded emotions were non-normally distributed whereas responses to positively-worded emotions were normally distributed. Emotion predicted diet, exercise, and sleep quality whereas stress predicted only sleep quality. As stress was a poor predictor of health behaviors and responses to stress and negatively worded emotions were non-normally distributed it may suggests correctional employees are under-reporting stress and negative emotions. PMID:27547828

Psychological Health and Overweight and Obesity Among High Stressed Work Environments.

PubMed

Faghri, Pouran D; Mignano, Christina; Huedo-Medina, Tania B; Cherniack, Martin

2015-07-01

Correctional employees are recognized to underreport stress and stress symptoms and are known to have a culture that discourages appearing "weak" and seeking psychiatric help. This study assesses underreporting of stress and emotions. Additionally, it evaluates the relationships between stress and emotions on health behaviors. Correctional employees (n=317) completed physical assessments to measure body mass index (BMI), and surveys to assess perceived stress, emotions, and health behavior (diet, exercise, and sleep quality). Stress and emotion survey items were evaluated for under-reporting via skewness, kurtosis, and visual assessment of histograms. Structural equation modeling evaluated relationships between stress/emotion and health behaviors. Responses to stress and negatively worded emotions were non-normally distributed whereas responses to positively-worded emotions were normally distributed. Emotion predicted diet, exercise, and sleep quality whereas stress predicted only sleep quality. As stress was a poor predictor of health behaviors and responses to stress and negatively worded emotions were non-normally distributed it may suggests correctional employees are under-reporting stress and negative emotions.

Clinical significance of stress-related increase in blood pressure: current evidence in office and out-of-office settings.

PubMed

Munakata, Masanori

2018-05-29

High blood pressure is the most significant risk factor of cardiovascular and cerebrovascular diseases worldwide. Blood pressure and its variability are recognized as risk factors. Thus, hypertension control should focus not only on maintaining optimal levels but also on achieving less variability in blood pressure. Psychosocial stress is known to contribute to the development and worsening of hypertension. Stress is perceived by the brain and induces neuroendocrine responses in either a rapid or long-term manner. Moreover, endothelial dysfunction and inflammation might be further involved in the modulation of blood pressure elevation associated with stress. White-coat hypertension, defined as high clinic blood pressure but normal out-of-office blood pressure, is the most popular stress-related blood pressure response. Careful follow-up is necessary for this type of hypertensive patients because some show organ damage or a worse prognosis. On the other hand, masked hypertension, defined as high out-of-office blood pressure but normal office blood pressure, has received considerable interest as a poor prognostic condition. The cause of masked hypertension is complex, but evidence suggests that chronic stress at the workplace or home could be involved. Chronic psychological stress could be associated with distorted lifestyle and mental distress as well as long-lasting allostatic load, contributing to the maintenance of blood pressure elevation. Stress issues are common in patients in modern society. Considering psychosocial stress as the pathogenesis of blood pressure elevation is useful for achieving an individual-focused approach and 24-h blood pressure control.

Perturbation of Auxin Homeostasis and Signaling by PINOID Overexpression Induces Stress Responses in Arabidopsis

PubMed Central

Saini, Kumud; AbdElgawad, Hamada; Markakis, Marios N.; Schoenaers, Sébastjen; Asard, Han; Prinsen, Els; Beemster, Gerrit T. S.; Vissenberg, Kris

2017-01-01

Under normal and stress conditions plant growth require a complex interplay between phytohormones and reactive oxygen species (ROS). However, details of the nature of this crosstalk remain elusive. Here, we demonstrate that PINOID (PID), a serine threonine kinase of the AGC kinase family, perturbs auxin homeostasis, which in turn modulates rosette growth and induces stress responses in Arabidopsis plants. Arabidopsis mutants and transgenic plants with altered PID expression were used to study the effect on auxin levels and stress-related responses. In the leaves of plants with ectopic PID expression an accumulation of auxin, oxidative burst and disruption of hormonal balance was apparent. Furthermore, PID overexpression led to the accumulation of antioxidant metabolites, while pid knockout mutants showed only moderate changes in stress-related metabolites. These physiological changes in the plants overexpressing PID modulated their response toward external drought and osmotic stress treatments when compared to the wild type. Based on the morphological, transcriptome, and metabolite results, we propose that perturbations in the auxin hormone levels caused by PID overexpression, along with other hormones and ROS downstream, cause antioxidant accumulation and modify growth and stress responses in Arabidopsis. Our data provide further proof for a strong correlation between auxin and stress biology. PMID:28824662

Antidepressant-like effects of oleoylethanolamide in a mouse model of chronic unpredictable mild stress.

PubMed

Jin, Peng; Yu, Hai-Ling; Tian-Lan; Zhang, Feng; Quan, Zhe-Shan

2015-06-01

Oleoylethanolamide (OEA) is an endocannabinoid analog that belongs to a family of endogenous acylethanolamides. Increasing evidence suggests that OEA may act as an endogenous neuroprotective factor and participate in the control of mental disorder-related behaviors. In this study, we examined whether OEA is effective against depression and investigated the role of circulating endogenous acylethanolamides during stress. Mice were subjected to 28days of chronic unpredictable mild stress (CUMS), and during the last 21days, treated with oral OEA (1.5-6mg/kg) or 6mg/kg fluoxetine. Sucrose preference and open field test activity were used to evaluate depression-like behaviors during CUMS and after OEA treatment. Weights of the prefrontal cortex and hippocampus were determined, and the adrenal index was measured. Furthermore, changes in serum adrenocorticotropic hormone (ACTH), corticosterone (CORT) and total antioxidant capacity (T-AOC), brain-derived neurotrophic factor (BDNF), and lipid peroxidation product malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activities in the hippocampus and prefrontal cortex were detected. Our findings indicate that OEA normalized sucrose preferences, locomotion distances, rearing frequencies, prefrontal cortex and hippocampal atrophy, and adrenal indices. In addition, OEA reversed the abnormalities of BDNF and MDA levels and SOD activities in the hippocampus and prefrontal cortex, as well as changes in serum levels of ACTH, CORT, and T-AOC. The antidepressant effects of OEA may be related to the regulation of BDNF levels in the hippocampus and prefrontal cortex, antioxidant defenses, and normalizing hyperactivity in the hypothalamic-pituitary-adrenal axis (HPA). Copyright © 2015 Elsevier Inc. All rights reserved.

High self-perceived stress and many stressors, but normal diurnal cortisol rhythm, in adults with ADHD (attention-deficit/hyperactivity disorder).

PubMed

Hirvikoski, Tatja; Lindholm, Torun; Nordenström, Anna; Nordström, Anna-Lena; Lajic, Svetlana

2009-03-01

Attention-deficit/hyperactivity disorder (ADHD) in adults is associated with significant impairment in many life activities and may thus increase the risk of chronic stress in everyday life. We compared adults with a DSM-IV ADHD diagnosis (n=28) with healthy controls (n=28) regarding subjective stress and amounts of stressors in everyday life, diurnal salivary cortisol in the everyday environment and salivary cortisol before and after cognitive stress in a laboratory setting. The association between cortisol concentrations and impulsivity was also investigated. Consistent with assumptions, individuals with ADHD reported significantly more self-perceived stress than controls, and subjective stress correlated with the amount of stressors in everyday life. The two groups were comparable with respect to overall diurnal cortisol levels and rhythm, as well as in pre- and post-stress cortisol concentrations. Post-stress cortisol (but not baseline cortisol) concentration was positively correlated with impulsivity. The group with high post-stress cortisol also reported more symptoms of depression and anxiety, as well as self-perceived stress and stressors in every-day life. The diagnosis of ADHD significantly increased the risk of belonging to the group with high post-stress cortisol levels. The results in this study warrant a focus not only on the primary diagnosis of ADHD, but also calls for a broader assessment of stressors and subjective stress in everyday life, as well as support comprising stress management and coping skills.

Prevention of psychological stress-induced immune suppression by aged garlic extract.

PubMed

Kyo, E; Uda, N; Ushijima, M; Kasuga, S; Itakura, Y

1999-11-01

We determined the effect of Aged Garlic Extract (AGE) on damage caused to immune function by a psychological stress using a communication box. After four days of a psychological stress, a decrease in spleen weight and spleen cells was observed in the psychological stress-exposed mice as compared normal mice (non-stress). AGE significantly prevented the decreases in spleen weight and cells. Additionally, AGE significantly prevented the reduction of hemolytic plaque-forming-cells in spleen cells and anti-SRBC antibody titer in serum caused by this psychological stress. Moreover, a reduction in NK activities was observed in the psychological stress-exposed mice as compared with normal mice (non-stress), whereas NK activities in the AGE administered mice were almost the same as normal mice (non-stress). These results indicate that psychological stress qualitatively and quantitatively impairs immune function, and that AGE is extremely useful for preventing psychologically-induced damage.

Influence of bacterial kidney disease on smoltification in salmonids: Is it a case of double jeopardy?

USGS Publications Warehouse

Mesa, M.G.; Maule, A.G.; Poe, T.P.; Schreck, C.B.

1999-01-01

We investigated the effects of a chronic, progressive infection with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), on selected aspects of smoltification in yearling juvenile spring chinook salmon (Oncorhynchus tshawytscha). After experimentally infecting fish with Rs using an immersion challenge, we sampled them every two weeks to monitor changes in gill Na+, K+-ATPase (ATPase), cortisol, infection level, mortality, growth, and other stress-related physiological factors during the normal time of parr-smolt transformation in fresh water (i.e., from winter to spring). A progressively worsening infection with Rs did not alter the normal changes in gill ATPase and condition factor associated with smoltification in juvenile chinook salmon. The infection did, however, lead to elevated levels of plasma cortisol and lactate and depressed levels of plasma glucose, indicating that the disease is stressful during the later stages. A dramatic proliferation of BKD was associated with maximal responses of indicators of smoltification, suggesting that the process of smoltification itself can trigger outbreaks of disease. Our results suggest mechanisms that probably influence the reported inability of Rs-infected fish to successfully adapt to sea water.

Neuronal Responses to Physiological Stress

PubMed Central

Kagias, Konstantinos; Nehammer, Camilla; Pocock, Roger

2012-01-01

Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, due to an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level. PMID:23112806

Changes of testicular phosphorylated proteins in response to restraint stress in male rats*

PubMed Central

Arun, Supatcharee; Burawat, Jaturon; Sukhorum, Wannisa; Sampannang, Apichakan; Uabundit, Nongnut; Iamsaard, Sitthichai

2016-01-01

Objective: To investigate male reproductive parameters via changes of potential testicular protein markers in restraint-stress rats. Methods: Male Sprague-Dawley rats were divided into two groups (non-immobilized control and restraint-immobilized/stress groups, n=8 each group). The stress animals were immobilized (12 h/d) by a restraint cage for 7 consecutive days. All reproductive parameters, morphology and histology were observed and compared between groups. In addition, the expression of steroidogenic acute regulatory (StAR) and phosphotyrosine proteins (previously localized in Sertoli and late spermatid cells) in testicular lysate was assayed by immuno-Western blotting. Results: Testosterone level, sperm concentration and sperm head normality of stress rats were significantly decreased while the corticosterone level was increased as compared with the control (P<0.05). Histologically, stress rats showed low sperm mass in epididymal lumen and some atrophy of seminiferous tubules. Although the expression of testicular StAR protein was not significantly different between groups, changed patterns of the 131, 95, and 75 kDa testicular phosphorylated proteins were observed in the stress group compared with the control group. The intensity of a testicular 95-kDa phosphorylated protein was significantly decreased in stress rats. Conclusions: This study has demonstrated the alteration of testicular phosphorylated protein patterns, associated with adverse male reproductive parameters in stress rats. It could be an explanation of some infertility in stress males. PMID:26739523

Discrimination, Psychosocial Stress, and Health among Latin American Immigrants in Oregon

PubMed Central

McClure, Heather H.; Snodgrass, J. Josh; Martinez, Charles R.; Eddy, J. Mark; Jiménez, Roberto A.; Isiordia, Laura E.

2009-01-01

Chronic psychosocial stress related to discrimination has been shown to be associated with biological measures such as elevated systolic blood pressure (SBP), increased body fat, and higher fasting glucose levels. Few studies have examined this relationship in immigrant populations. The present study recruited a sample of 132 Oregon Latino immigrant adults in order to investigate the relationships between perceived discrimination and several health measures (blood pressure, body mass index [BMI], and fasting glucose). Results indicate that perceived discrimination stress predicted elevated SBP among men but not among women. Perceived discrimination was significantly higher among obese women than among women of normal BMI. The same pattern was not observed for men. Further, a strong trend relationship was detected: the higher women’s reported discrimination stress, the higher their fasting glucose levels. Again, this pattern was not observed for men. These results suggest that chronic psychosocial stress plays an important role in disease risk among Latin American immigrants, and that male and female immigrants may have distinctive physiological responses. If confirmed, these findings may have important clinical and public health implications for chronic disease prevention among Latinos. PMID:19844904

Iodinated Contrast Media Can Induce Long-Lasting Oxidative Stress in Hemodialysis Patients

PubMed Central

Hwang, Seun Deuk; Kim, Yoon Ji; Lee, Sang Heun; Cho, Deok Kyu; Cho, Yun Hyeong; Moon, Sung Jin; Lee, Sang Choel

2013-01-01

Purpose Due to their comorbidities, dialysis patients have many chances to undergo radiologic procedures using iodinated contrast media. We aimed to assess time-sequenced blood oxidative stress level after contrast exposure in hemodialysis (HD) patients compared to those in the non-dialysis population. Materials and Methods We included 21 anuric HD patients [HD-coronary angiography (CAG) group] and 23 persons with normal renal function (nonHD-CAG group) scheduled for CAG, and assessed 4 oxidative stress markers [advanced oxidation protein products (AOPP); catalase; 8-hydroxydeoxyguanosine; and malondialdehyde] before and after CAG, and subsequently up to 28 days. Results In the nonHD-CAG group, only AOPP increased immediately after CAG and returned to baseline within one day. However, in the HD-CAG group, all four oxidative stress markers were significantly increased starting one day after CAG, and remained elevated longer than those in the nonHD-CAG group. Especially, AOPP level remained elevated for a month after contrast exposure. Conclusion Our study showed that iodinated contrast media induces severe and prolonged oxidative stress in HD patients. PMID:24142649

Insulin/IGF-1 signaling mutants reprogram ER stress response regulators to promote longevity.

PubMed

Henis-Korenblit, Sivan; Zhang, Peichuan; Hansen, Malene; McCormick, Mark; Lee, Seung-Jae; Cary, Michael; Kenyon, Cynthia

2010-05-25

When unfolded proteins accumulate in the endoplasmic reticulum (ER), the unfolded protein response is activated. This ER stress response restores ER homeostasis by coordinating processes that decrease translation, degrade misfolded proteins, and increase the levels of ER-resident chaperones. Ribonuclease inositol-requiring protein-1 (IRE-1), an endoribonuclease that mediates unconventional splicing, and its target, the XBP-1 transcription factor, are key mediators of the unfolded protein response. In this study, we show that in Caenorhabditis elegans insulin/IGF-1 pathway mutants, IRE-1 and XBP-1 promote lifespan extension and enhance resistance to ER stress. We show that these effects are not achieved simply by increasing the level of spliced xbp-1 mRNA and expression of XBP-1's normal target genes. Instead, in insulin/IGF-1 pathway mutants, XBP-1 collaborates with DAF-16, a FOXO-transcription factor that is activated in these mutants, to enhance ER stress resistance and to activate new genes that promote longevity.

The impact of lexical-semantic impairment and of executive dysfunction on the word reading performance of patients with probable Alzheimer dementia.

PubMed

Colombo, Lucia; Fonti, Cristina; Cappa, Stefano

2004-01-01

The influence of lexical-semantic impairment and of executive dysfunction on word naming performance was investigated in a group of patients with probable Alzheimer dementia (AD). The patients, who varied in the severity of the illness, were tested in a word naming task where they had to read aloud Italian three-syllable words with a dominant or subordinate stress pattern. These types of words have been shown to interact with frequency in normal adults [J. Exp. Psychol.: Hum. Percept. Perform. 18 (4) (1992) 987], so that the effect of the subordinate stress pattern (slower reading times) is only apparent for low frequency words. The frequency and stress effects on accuracy increased across dementia severity levels. Regression analyses showed that the impairment in reading low frequency words with subordinate stress depended largely on the level of lexical-semantic impairment, measured by a test of semantic memory and comprehension. Implications for the current reading models are discussed.

Oxidative stress and Na,K-ATPase activity differential regulation in brainstem and forebrain of Wistar Audiogenic rats may lead to increased seizure susceptibility.

PubMed

Parreira, Gabriela Machado; Resende, Maria Daniela Aparecida; Garcia, Israel José Pereira; Sartori, Daniela Bueno; Umeoka, Eduardo Henrique de Lima; Godoy, Lívea Dornela; Garcia-Cairasco, Norberto; Barbosa, Leandro Augusto; Santos, Hérica de Lima; Tilelli, Cristiane Queixa

2018-01-15

The Wistar Audiogenic Rat (WAR) is a well-characterized seizure-prone, inbred rodent strain that, when acutely stimulated with high-intensity sounds, develops brainstem-dependent tonic-clonic seizures that can evolve to limbic-like, myoclonic (forebrain) seizures when the acoustic stimuli are presented chronically (audiogenic kindling). In order to investigate possible mechanisms underlying WAR susceptibility to seizures, we evaluated Na,K-ATPase activity, Ca-ATPase activity, Mg-ATPase activity, lipid membrane composition and oxidative stress markers in whole forebrain and whole brainstem samples of naïve WAR, as compared to samples from control Wistar rats. We also evaluated the expression levels of α1 and α3 isoforms of Na,K-ATPase in forebrain samples. We observed increased Na,K-ATPase activity in forebrain samples and increased oxidative stress markers (lipid peroxidation, glutathione peroxidase and superoxide dismutase) in brainstem samples of WAR. The Ca-ATPase activity, Mg-ATPase activity, lipid membrane composition and expression levels of α1 and α3 isoforms of Na,K-ATPase were unaltered. In view of previous data showing that the membrane potentials from naïve WAR's neurons are less negative than that from neurons from Wistar rats, we suggest that Na,K-ATPase increased activity might be involved in a compensatory mechanism necessary to maintain WAR's brains normal activity. Additionally, ongoing oxidative stress in the brainstem could bring Na,K-ATPase activity back to normal levels, which may explain why WAR's present increased susceptibility to seizures triggered by high-intensity sound stimulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Caffeine affects cardiovascular and neuroendocrine activation at work and home.

PubMed

Lane, James D; Pieper, Carl F; Phillips-Bute, Barbara G; Bryant, John E; Kuhn, Cynthia M

2002-01-01

This study investigated the effects of moderate doses of caffeine on ambulatory blood pressure and heart rate, urinary excretion of epinephrine, norepinephrine, and cortisol, and subjective measures of stress during normal activities at work and at home in the evening. Healthy, nonsmoking, habitual coffee drinkers (N = 47) participated in 3 days of ambulatory study. After a day of ad lib caffeine consumption, caffeine (500 mg) and placebo were administered double-blind in counter-balanced order on separate workdays. Ambulatory blood pressure and heart rate were monitored from the start of the workday until bedtime. Urinary excretion of catecholamines and cortisol was assessed during the workday and evening. Caffeine administration significantly raised average ambulatory blood pressure during the workday and evening by 4/3 mm Hg and reduced average heart rate by 2 bpm. Caffeine also increased by 32% the levels of free epinephrine excreted during the workday and the evening. In addition, caffeine amplified the increases in blood pressure and heart rate associated with higher levels of self-reported stress during the activities of the day. Effects were undiminished through the evening until bedtime. Caffeine has significant hemodynamic and humoral effects in habitual coffee drinkers that persist for many hours during the activities of everyday life. Furthermore, caffeine may exaggerate sympathetic adrenal-medullary responses to the stressful events of normal daily life. Repeated daily blood pressure elevations and increases in stress reactivity caused by caffeine consumption could contribute to an increased risk of coronary heart disease in the adult population.

Stress response in Caenorhabditis elegans caused by optical tweezers: wavelength, power, and time dependence.

PubMed Central

Leitz, Guenther; Fällman, Erik; Tuck, Simon; Axner, Ove

2002-01-01

Optical tweezers have emerged as a powerful technique for micromanipulation of living cells. Although the technique often has been claimed to be nonintrusive, evidence has appeared that this is not always the case. This work presents evidence that near-infrared continuous-wave laser light from optical tweezers can produce stress in Caenorhabditis elegans. A transgenic strain of C. elegans, carrying an integrated heat-shock-responsive reporter gene, has been exposed to laser light under a variety of illumination conditions. It was found that gene expression was most often induced by light of 760 nm, and least by 810 nm. The stress response increased with laser power and irradiation time. At 810 nm, significant gene expression could be observed at 360 mW of illumination, which is more than one order of magnitude above that normally used in optical tweezers. In the 700-760-nm range, the results show that the stress response is caused by photochemical processes, whereas at 810 nm, it mainly has a photothermal origin. These results give further evidence that the 700-760-nm wavelength region is unsuitable for optical tweezers and suggest that work at 810 nm at normal laser powers does not cause stress at the cellular level. PMID:11916877

Mechanobiology in Lung Epithelial Cells: Measurements, Perturbations, and Responses

PubMed Central

Waters, Christopher M.; Roan, Esra; Navajas, Daniel

2015-01-01

Epithelial cells of the lung are located at the interface between the environment and the organism and serve many important functions including barrier protection, fluid balance, clearance of particulate, initiation of immune responses, mucus and surfactant production, and repair following injury. Because of the complex structure of the lung and its cyclic deformation during the respiratory cycle, epithelial cells are exposed to continuously varying levels of mechanical stresses. While normal lung function is maintained under these conditions, changes in mechanical stresses can have profound effects on the function of epithelial cells and therefore the function of the organ. In this review, we will describe the types of stresses and strains in the lungs, how these are transmitted, and how these may vary in human disease or animal models. Many approaches have been developed to better understand how cells sense and respond to mechanical stresses, and we will discuss these approaches and how they have been used to study lung epithelial cells in culture. Understanding how cells sense and respond to changes in mechanical stresses will contribute to our understanding of the role of lung epithelial cells during normal function and development and how their function may change in diseases such as acute lung injury, asthma, emphysema, and fibrosis. PMID:23728969

Transcriptome-Wide Identification of Reference Genes for Expression Analysis of Soybean Responses to Drought Stress along the Day.

PubMed

Marcolino-Gomes, Juliana; Rodrigues, Fabiana Aparecida; Fuganti-Pagliarini, Renata; Nakayama, Thiago Jonas; Ribeiro Reis, Rafaela; Bouças Farias, Jose Renato; Harmon, Frank G; Correa Molinari, Hugo Bruno; Correa Molinari, Mayla Daiane; Nepomuceno, Alexandre

2015-01-01

The soybean transcriptome displays strong variation along the day in optimal growth conditions and also in response to adverse circumstances, like drought stress. However, no study conducted to date has presented suitable reference genes, with stable expression along the day, for relative gene expression quantification in combined studies on drought stress and diurnal oscillations. Recently, water deficit responses have been associated with circadian clock oscillations at the transcription level, revealing the existence of hitherto unknown processes and increasing the demand for studies on plant responses to drought stress and its oscillation during the day. We performed data mining from a transcriptome-wide background using microarrays and RNA-seq databases to select an unpublished set of candidate reference genes, specifically chosen for the normalization of gene expression in studies on soybean under both drought stress and diurnal oscillations. Experimental validation and stability analysis in soybean plants submitted to drought stress and sampled during a 24 h timecourse showed that four of these newer reference genes (FYVE, NUDIX, Golgin-84 and CYST) indeed exhibited greater expression stability than the conventionally used housekeeping genes (ELF1-β and β-actin) under these conditions. We also demonstrated the effect of using reference candidate genes with different stability values to normalize the relative expression data from a drought-inducible soybean gene (DREB5) evaluated in different periods of the day.

[Effect of the thyroid status on the proteinases/inhibitors system under stress].

PubMed

Gorodetskaya, I V; Gusakova, E A

2015-01-01

Тhe alarm-stage of stress reaction (аn hour after the stress of swimming of rats in a cage during an hour) is characterized by the stimulation of trypsinе-like activity (TLA) in the liver, and especially in the blood. At the resistance stage (48 hours after the stress) there is normalization of TLA in the blood and limitation of its growth in the liver. At the stage of exhaustion (an hour of stress during 10 days) the most significant increase of TLA in the liver and blood develops. Experimental hypothyroidism (25 mg/kg merkazolil within 20 days) per se causes a reduction of TLA, defines more pronounced stimulation of proteolysis in the alarm-stage, prevents its normalization at the resistance-stage, and promotes its excessive activation at the stage of exhaustion. Introduction of small doses of L-thyroxine (1.5-3.0 g/kg during 28 days) does not affect the system of proteolysis, limitis the increase of TLA at the alarm- and exhaustion stages, prevents its stimulation at the resistance-stage. The dependence of the changes in the proteases/inhibitors system under stress from the level of iodine-containing thyroid hormones in the blood is due to their influence on the activity of endogenous proteinase inhibitors (a1-antitrypsin and a2-macroglobulin) and on the permeability of lysosomes membranes.

eIF4E Threshold Levels Differ in Governing Normal and Neoplastic Expansion of Mammary Stem and Luminal Progenitor cells

PubMed Central

Avdulov, Svetlana; Herrera, Jeremy; Smith, Karen; Peterson, Mark; Gomez-Garcia, Jose R.; Beadnell, Thomas C.; Schwertfeger, Kathryn L.; Benyumov, Alexey O.; Manivel, J. Carlos; Li, Shunan; Bielinsky, Anja-Katrin; Yee, Douglas; Bitterman, Peter B.; Polunovsky, Vitaly A.

2015-01-01

Translation initiation factor eIF4E mediates normal cell proliferation, yet induces tumorigenesis when overexpressed. The mechanisms by which eIF4E directs such distinct biological outputs remains unknown. We found that mouse mammary morphogenesis during pregnancy and lactation is accompanied by increased cap-binding capability of eIF4E and activation of the eIF4E-dependent translational apparatus, but only subtle oscillations in eIF4E abundance. Using a transgenic mouse model engineered so that lactogenic hormones stimulate a sustained increase in eIF4E abundance in stem/progenitor cells of lactogenic mammary epithelium during successive pregnancy/lactation cycles, eIF4E overexpression increased cell self-renewal, triggered DNA replication stress, and induced formation of pre-malignant and malignant lesions. Using complementary in vivo and ex vivo approaches, we found that increasing eIF4E levels rescued cells harboring oncogenic c-Myc or H-RasV12 from DNA replication stress and oncogene-induced replication catastrophe. Our findings indicate that distinct threshold levels of eIF4E govern its biological output in lactating mammary glands, and that eIF4E overexpression in the context of stem/progenitor cell population expansion can initiate malignant transformation by enabling cells to evade DNA damage checkpoints activated by oncogenic stimuli. Maintaining eIF4E levels below its pro-neoplastic threshold is an important anticancer defense in normal cells, with important implications for understanding pregnancy-associated breast cancer. PMID:25524901

Autophagy levels are elevated in Barrett’s esophagus and promote cell survival from acid and oxidative stress

PubMed Central

Kong, Jianping; Whelan, Kelly A.; Laczkó, Dorottya; Dang, Brendan; Monroig, Angeliz Caro; Soroush, Ali; Falcone, John; Amaravadi, Ravi K.; Rustgi, Anil K.; Ginsberg, Gregory G; Falk, Gary W; Nakagawa, Hiroshi; Lynch, John P.

2015-01-01

Autophagy is a highly conserved mechanism that is activated during cellular stress. We hypothesized that autophagy may be induced by acid reflux, which causes injury and inflammation, and therefore contributes to the pathogenesis of Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC). Currently, the role of autophagy in BE and EAC is poorly studied. We quantitatively define autophagy levels in human BE cell lines, a transgenic mouse model of BE, and human BE and EAC biopsies. Human non-dysplastic BE had the highest basal number of autophagic vesicles (AVs), while AVs were reduced in normal squamous cells and dysplastic BE cells, and nearly absent in EAC. To demonstrate a functional role for autophagy in BE pathogenesis, normal squamous (STR), non-dysplastic BE (CPA), dysplastic BE (CPD), and esophageal adenocarcinoma (OE19) cell lines were exposed to an acid pulse (pH3.5) followed by incubation in the presence or absence of chloroquine, an autophagy inhibitor. Acid exposure increased reactive oxygen species (ROS) levels in STR and CPA cells. Chloroquine alone had a small impact on intracellular ROS or cell survival. However, combination of chloroquine with the acid pulse resulted in a significant increase in ROS levels at 6 hours in STR and CPA cells, and increased cell death in all cell lines. These findings establish increased numbers of AVs in human BE compared to normal squamous or EAC, and suggest that autophagy functions to improve cell survival after acid reflux injury. Autophagy may thus play a critical role in BE pathogenesis and progression. PMID:26373456

eIF4E threshold levels differ in governing normal and neoplastic expansion of mammary stem and luminal progenitor cells.

PubMed

Avdulov, Svetlana; Herrera, Jeremy; Smith, Karen; Peterson, Mark; Gomez-Garcia, Jose R; Beadnell, Thomas C; Schwertfeger, Kathryn L; Benyumov, Alexey O; Manivel, J Carlos; Li, Shunan; Bielinsky, Anja-Katrin; Yee, Douglas; Bitterman, Peter B; Polunovsky, Vitaly A

2015-02-15

Translation initiation factor eIF4E mediates normal cell proliferation, yet induces tumorigenesis when overexpressed. The mechanisms by which eIF4E directs such distinct biologic outputs remain unknown. We found that mouse mammary morphogenesis during pregnancy and lactation is accompanied by increased cap-binding capability of eIF4E and activation of the eIF4E-dependent translational apparatus, but only subtle oscillations in eIF4E abundance. Using a transgenic mouse model engineered so that lactogenic hormones stimulate a sustained increase in eIF4E abundance in stem/progenitor cells of lactogenic mammary epithelium during successive pregnancy/lactation cycles, eIF4E overexpression increased self-renewal, triggered DNA replication stress, and induced formation of premalignant and malignant lesions. Using complementary in vivo and ex vivo approaches, we found that increasing eIF4E levels rescued cells harboring oncogenic c-Myc or H-RasV12 from DNA replication stress and oncogene-induced replication catastrophe. Our findings indicate that distinct threshold levels of eIF4E govern its biologic output in lactating mammary glands and that eIF4E overexpression in the context of stem/progenitor cell population expansion can initiate malignant transformation by enabling cells to evade DNA damage checkpoints activated by oncogenic stimuli. Maintaining eIF4E levels below its proneoplastic threshold is an important anticancer defense in normal cells, with important implications for understanding pregnancy-associated breast cancer. ©2014 American Association for Cancer Research.

Dietary antioxidents and oxidative stress in predialysis chronic kidney disease patients

PubMed Central

L Gupta, Krishan; Sahni, Nancy

2012-01-01

Context Dietary antioxidants are important in protecting against human diseases. Oxidative stress, a non- traditional risk factors of cardio-vascular disease is far more prevalent in chronic kidney disease (CKD) patients than in normal subjects. Evidence Acquisitions Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched. Results Oxidative stress could be a consequence of an increase in reactive oxygen species as well as a decrease in antioxidant defenses. Among the important factors that can be involved in triggering oxidative stress is insufficient dietary intake of antioxidants. Malnourished CKD patients are reported to have more oxidative stress than well nourished ones. Conclusions Moving beyond the importance of assessment of dietary protein and energy in pre dialysis CKD patients to the assessment of dietary antioxidants is of utmost importance to help combat enhanced oxidative stress levels in such patients. PMID:24475404

Dietary antioxidents and oxidative stress in predialysis chronic kidney disease patients.

PubMed

L Gupta, Krishan; Sahni, Nancy

2012-10-01

Dietary antioxidants are important in protecting against human diseases. Oxidative stress, a non- traditional risk factors of cardio-vascular disease is far more prevalent in chronic kidney disease (CKD) patients than in normal subjects. Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched. Oxidative stress could be a consequence of an increase in reactive oxygen species as well as a decrease in antioxidant defenses. Among the important factors that can be involved in triggering oxidative stress is insufficient dietary intake of antioxidants. Malnourished CKD patients are reported to have more oxidative stress than well nourished ones. Moving beyond the importance of assessment of dietary protein and energy in pre dialysis CKD patients to the assessment of dietary antioxidants is of utmost importance to help combat enhanced oxidative stress levels in such patients.

Nonlinear Reduced-Order Simulation Using Stress-Free and Pre-Stressed Modal Bases

NASA Technical Reports Server (NTRS)

Przekop, Adam; Stover, Michael A.; Rizzi, Stephen A.

2009-01-01

A study is undertaken to determine the advantages and disadvantages associated with application of stress-free and pre-stressed modal bases in a reduced-order finite-element-based nonlinear simulation. A planar beam is chosen as an application example and its response due to combined thermal and random pressure loadings is examined. Combinations of two random pressure levels and two thermal conditions are investigated. The latter consists of an ambient temperature condition and an elevated temperature condition in the post-buckled regime. It is found that stress-free normal modes establish a broadly applicable modal basis yielding accurate results for all the loading regimes considered. In contrast, the range of applicability for a thermally pre-stressed modal basis is found to be limited. The behavior is explained by scrutinizing the coupling found in the linear stiffness and the effect this coupling has on the structural response characteristics under the range of loading conditions considered.

CD4+ T cells are important mediators of oxidative stress that cause hypertension in response to placental ischemia.

PubMed

Wallace, Kedra; Cornelius, Denise C; Scott, Jeremy; Heath, Judith; Moseley, Janae; Chatman, Krystal; LaMarca, Babbette

2014-11-01

Preeclampsia is associated with oxidative stress, which is suspected to play a role in hypertension, placental ischemia, and fetal demise associated with the disease. Various cellular sources of oxidative stress, such as neutrophils, monocytes, and CD4(+) T cells have been suggested as culprits in the pathophysiology of preeclampsia. The objective of this study was to examine a role of circulating and placental CD4(+) T cells in oxidative stress in response to placental ischemia during pregnancy. CD4(+) T cells and oxidative stress were measured in preeclamptic and normal pregnant women, placental ischemic and normal pregnant rats, and normal pregnant recipient rats of placental ischemic CD4(+) T cells. Women with preeclampsia had significantly increased circulating (P=0.02) and placental CD4(+) T cells (P=0.0001); lymphocyte secretion of myeloperoxidase (P=0.004); and placental reactive oxygen species (P=0.0004) when compared with normal pregnant women. CD4(+) T cells from placental ischemic rats cause many facets of preeclampsia when injected into normal pregnant recipient rats on gestational day 13. On gestational day 19, blood pressure increased in normal pregnant recipients of placental ischemic CD4(+) T cells (P=0.002) compared with that in normal pregnant rats. Similar to preeclamptic patients, CD4(+) T cells from placental ischemic rats secreted significantly more myeloperoxidase (P=0.003) and induced oxidative stress in cultured vascular cells (P=0.003) than normal pregnant rat CD4(+)Tcells. Apocynin, a nicotinamide adenine dinucleotide phosphate inhibitor, attenuated hypertension and all oxidative stress markers in placental ischemic and normal pregnant recipient rats of placental ischemic CD4(+)Tcells (P=0.05). These data demonstrate an important role for CD4(+) T cells in mediating another factor, oxidative stress, to cause hypertension during preeclampsia. © 2014 American Heart Association, Inc.

Characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks

NASA Astrophysics Data System (ADS)

Almrabat, Abdulhadi M.

The thesis presents the results of a study of the characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks. A new laboratory High Pressure and High Temperature (HPHT) triaxial testing system was developed to characterize the seismic properties of sandstone under different levels of effective stress confinement and changes in pore-fluid composition. An intact and fractured of Berea sandstones core samples were used in the experimental studies. The laboratory test results were used to develop analytical models for stress-level and pore-fluid dependent seismic velocity of sandstones. Models for stress-dependent P and S-wave seismic velocities of sandstone were then developed based on the assumption that stress-dependencies come from the nonlinear elastic response of micro-fractures contained in the sample under normal and shear loading. The contact shear stiffness was assumed to increase linearly with the normal stress across a micro-fracture, while the contact normal stiffness was assumed to vary as a power law with the micro-fracture normal stress. Both nonlinear fracture normal and shear contact models were validated by experimental data available in the literature. To test the dependency of seismic velocity of sandstone on changes in pore-fluid composition, another series of tests were conducted where P and S-wave velocities were monitored during injection of supercritical CO 2 in samples of Berea sandstone initially saturated with saline water and under constant confining stress. Changes in seismic wave velocity were measured at different levels of supercritical CO2 saturation as the initial saline water as pore-fluid was displaced by supercritical CO 2. It was found that the P- iv wave velocity significantly decreased while the S-wave velocity remained almost constant as the sample supercritical CO2 saturation increased. The dependency of the seismic velocity on changes on pore fluid composition during injection of supercritical CO 2 in Berea sandstone was modeled using a re-derived Biot-Gassmann substitution theory. In using the Biot-Gassmann substitution theory, it was found necessary to account for the changes in the pore-fluid compressibility in terms of the volumetric proportion and distribution of saline water and supercritical CO 2 in the sample pore space. This was done by using the empirical model of Brie et al. to account for the compressibility of mixtures of two-phase immiscible fluids. The combined Biot-Gassman and Brie et al. models were found to represent adequately the changes in P-wave velocity of Berea sandstone during displacement of saline water by supercritical CO2. The third experimental and modeling study addressed shear-wave splitting due to the presence of fractures in a rock mass. Tests were conducted using the high temperature and high pressure (HPHT) triaxial device on samples of Berea sandstone, containing a single induced tensile fracture running along the height of the sample. The fracture was created via a modified Brazilian Split Test loading where the edges of cylindrical samples were loaded on diametrically opposite two points by sharp guillotines. The Joint Roughness Coefficient (JRC) values of the fractured core samples were determined by profilometry and tilt test. The effect of mismatching of the fracture surfaces on shear wave splitting was investigated by applying different amounts of shear displacements to three core samples. The degree of mismatching of the fracture surfaces in the core samples was evaluated using the Joint Matching Coefficient (JMC). Shear-wave splitting, as measured by the difference in magnitudes of shear-wave velocities parallel and perpendicular to the fracture, Vs1 and Vs2 respectively, increases with increasing mismatch of the fracture surfaces and decreases with increasing effective stress, and approaches zero in the effective stress range tested. A model for the stress and JMC dependent shear-wave splitting was developed based on the experimental observations. Finally, the magnitude of shear-wave splitting was correlated with the permeability of the fractured porous sandstone for fluid flow parallel to the induced fracture. (Abstract shortened by UMI.)

Mucuna pruriens Reduces Stress and Improves the Quality of Semen in Infertile Men

PubMed Central

Shukla, Kamla Kant; Ahmad, Mohammad Kaleem; Jaiswar, Shyam Pyari; Shankwar, Satya Narain; Tiwari, Sarvada Chandra

2010-01-01

The present investigation was undertaken to assess the role of Mucuna pruriens in infertile men who were under psychological stress. Study included 60 subjects who were undergoing infertility screening and were found to be suffering from psychological stress, assessed on the basis of a questionnaire and elevated serum cortisol levels. Age-matched 60 healthy men having normal semen parameters and who had previously initiated at least one pregnancy were included as controls. Infertile subjects were administered with M. pruriens seed powder (5 g day−1) orally. For carrying out morphological and biochemical analysis, semen samples were collected twice, first before starting treatment and second after 3 months of treatment. The results demonstrated decreased sperm count and motility in subjects who were under psychological stress. Moreover, serum cortisol and seminal plasma lipid peroxide levels were also found elevated along with decreased seminal plasma glutathione (GSH) and ascorbic acid contents and reduced superoxide dismutase (SOD) and catalase activity. Treatment with M. pruriens significantly ameliorated psychological stress and seminal plasma lipid peroxide levels along with improved sperm count and motility. Treatment also restored the levels of SOD, catalase, GSH and ascorbic acid in seminal plasma of infertile men. On the basis of results of the present study, it may be concluded that M. pruriens not only reactivates the anti-oxidant defense system of infertile men but it also helps in the management of stress and improves semen quality. PMID:18955292

Mucuna pruriens Reduces Stress and Improves the Quality of Semen in Infertile Men.

PubMed

Shukla, Kamla Kant; Mahdi, Abbas Ali; Ahmad, Mohammad Kaleem; Jaiswar, Shyam Pyari; Shankwar, Satya Narain; Tiwari, Sarvada Chandra

2010-03-01

The present investigation was undertaken to assess the role of Mucuna pruriens in infertile men who were under psychological stress. Study included 60 subjects who were undergoing infertility screening and were found to be suffering from psychological stress, assessed on the basis of a questionnaire and elevated serum cortisol levels. Age-matched 60 healthy men having normal semen parameters and who had previously initiated at least one pregnancy were included as controls. Infertile subjects were administered with M. pruriens seed powder (5 g day(-1)) orally. For carrying out morphological and biochemical analysis, semen samples were collected twice, first before starting treatment and second after 3 months of treatment. The results demonstrated decreased sperm count and motility in subjects who were under psychological stress. Moreover, serum cortisol and seminal plasma lipid peroxide levels were also found elevated along with decreased seminal plasma glutathione (GSH) and ascorbic acid contents and reduced superoxide dismutase (SOD) and catalase activity. Treatment with M. pruriens significantly ameliorated psychological stress and seminal plasma lipid peroxide levels along with improved sperm count and motility. Treatment also restored the levels of SOD, catalase, GSH and ascorbic acid in seminal plasma of infertile men. On the basis of results of the present study, it may be concluded that M. pruriens not only reactivates the anti-oxidant defense system of infertile men but it also helps in the management of stress and improves semen quality.

Oxidative stress mediated toxicity of TiO2 nanoparticles after a concentration and time dependent exposure of the aquatic macrophyte Hydrilla verticillata.

PubMed

Spengler, Annette; Wanninger, Lena; Pflugmacher, Stephan

2017-09-01

The present study focused on oxidative stress effects in the aquatic macrophyte Hydrilla verticillata after exposure to titanium dioxide nanoparticles (TiO 2 -NPs). Experiments were conducted with different TiO 2 -NPs and concentrations (0.1 mg/L and 10 mg/L) in a time-dependent manner (0 h, 24 h, 48 h, 96 h, 168 h). To assess various levels of the oxidative stress response in H. verticillata, the level of hydrogen peroxide (H 2 O 2 ), the ratio of reduced to oxidized glutathione (GSH/GSSG), and activities of the antioxidative enzymes catalase (CAT) and glutathione reductase (GR) were evaluated. Study results imply oxidative stress effects after TiO 2 -NP exposure as adaptations in plant metabolism became apparent to counteract increased ROS formation. All TiO 2 -NPs caused elevated activities of the enzymes CAT and GR. Moreover, decreased ratios of GSH/GSSG indicated an activation of GSH-dependent pathways counteracting ROS formation. Plants exposed to a bulk-sized control revealed a size-dependent influence on the antioxidative stress response. As H 2 O 2 level increases were solely detected after exposure to 10 mg/L TiO 2 -NPs and nano-exposed plants showed normalization in its antioxidative stress response after 168h of exposure, it can be suggested that macrophytes are able to cope with currently predicted low-level exposures to TiO 2 -NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Cardiovascular function in male and female JCR:LA-cp rats: effect of high-fat/high-sucrose diet.

PubMed

Hunter, Ian; Soler, Amanda; Joseph, Gregory; Hutcheson, Brenda; Bradford, Chastity; Zhang, Frank Fan; Potter, Barry; Proctor, Spencer; Rocic, Petra

2017-04-01

Thirty percent of the world population is diagnosed with metabolic syndrome. High-fat/high-sucrose (HF/HS) diet (Western diet) correlates with metabolic syndrome prevalence. We characterized effects of the HF/HS diet on vascular (arterial stiffness, vasoreactivity, and coronary collateral development) and cardiac (echocardiography) function, oxidative stress, and inflammation in a rat model of metabolic syndrome (JCR rats). Furthermore, we determined whether male versus female animals were affected differentially by the Western diet. Cardiovascular function in JCR male rats was impaired versus normal Sprague-Dawley (SD) rats. HF/HS diet compromised cardiovascular (dys)function in JCR but not SD male rats. In contrast, cardiovascular function was minimally impaired in JCR female rats on normal chow. However, cardiovascular function in JCR female rats on the HF/HS diet deteriorated to levels comparable to JCR male rats on the HF/HS diet. Similarly, oxidative stress was markedly increased in male but not female JCR rats on normal chow but was equally exacerbated by the HF/HS diet in male and female JCR rats. These results indicate that the Western diet enhances oxidative stress and cardiovascular dysfunction in metabolic syndrome and eliminates the protective effect of female sex on cardiovascular function, implying that both males and females with metabolic syndrome are at equal risk for cardiovascular disease. NEW & NOTEWORTHY Western diet abolished protective effect of sex against cardiovascular disease (CVD) development in premenopausal animals with metabolic syndrome. Western diet accelerates progression of CVD in male and female animals with preexisting metabolic syndrome but not normal animals. Exacerbation of baseline oxidative stress correlates with accelerated progression of CVD in metabolic syndrome animals on Western diet. Copyright © 2017 the American Physiological Society.

Cardiovascular function in male and female JCR:LA-cp rats: effect of high-fat/high-sucrose diet

PubMed Central

Hunter, Ian; Soler, Amanda; Joseph, Gregory; Hutcheson, Brenda; Bradford, Chastity; Zhang, Frank Fan; Potter, Barry; Proctor, Spencer

2017-01-01

Thirty percent of the world population is diagnosed with metabolic syndrome. High-fat/high-sucrose (HF/HS) diet (Western diet) correlates with metabolic syndrome prevalence. We characterized effects of the HF/HS diet on vascular (arterial stiffness, vasoreactivity, and coronary collateral development) and cardiac (echocardiography) function, oxidative stress, and inflammation in a rat model of metabolic syndrome (JCR rats). Furthermore, we determined whether male versus female animals were affected differentially by the Western diet. Cardiovascular function in JCR male rats was impaired versus normal Sprague-Dawley (SD) rats. HF/HS diet compromised cardiovascular (dys)function in JCR but not SD male rats. In contrast, cardiovascular function was minimally impaired in JCR female rats on normal chow. However, cardiovascular function in JCR female rats on the HF/HS diet deteriorated to levels comparable to JCR male rats on the HF/HS diet. Similarly, oxidative stress was markedly increased in male but not female JCR rats on normal chow but was equally exacerbated by the HF/HS diet in male and female JCR rats. These results indicate that the Western diet enhances oxidative stress and cardiovascular dysfunction in metabolic syndrome and eliminates the protective effect of female sex on cardiovascular function, implying that both males and females with metabolic syndrome are at equal risk for cardiovascular disease. NEW & NOTEWORTHY Western diet abolished protective effect of sex against cardiovascular disease (CVD) development in premenopausal animals with metabolic syndrome. Western diet accelerates progression of CVD in male and female animals with preexisting metabolic syndrome but not normal animals. Exacerbation of baseline oxidative stress correlates with accelerated progression of CVD in metabolic syndrome animals on Western diet. PMID:28087518

HPC in Basin Modeling: Simulating Mechanical Compaction through Vertical Effective Stress using Level Sets

NASA Astrophysics Data System (ADS)

McGovern, S.; Kollet, S. J.; Buerger, C. M.; Schwede, R. L.; Podlaha, O. G.

2017-12-01

In the context of sedimentary basins, we present a model for the simulation of the movement of ageological formation (layers) during the evolution of the basin through sedimentation and compactionprocesses. Assuming a single phase saturated porous medium for the sedimentary layers, the modelfocuses on the tracking of the layer interfaces, through the use of the level set method, as sedimentationdrives fluid-flow and reduction of pore space by compaction. On the assumption of Terzaghi's effectivestress concept, the coupling of the pore fluid pressure to the motion of interfaces in 1-D is presented inMcGovern, et.al (2017) [1] .The current work extends the spatial domain to 3-D, though we maintain the assumption ofvertical effective stress to drive the compaction. The idealized geological evolution is conceptualized asthe motion of interfaces between rock layers, whose paths are determined by the magnitude of a speedfunction in the direction normal to the evolving layer interface. The speeds normal to the interface aredependent on the change in porosity, determined through an effective stress-based compaction law,such as the exponential Athy's law. Provided with the speeds normal to the interface, the level setmethod uses an advection equation to evolve a potential function, whose zero level set defines theinterface. Thus, the moving layer geometry influences the pore pressure distribution which couplesback to the interface speeds. The flexible construction of the speed function allows extension, in thefuture, to other terms to represent different physical processes, analogous to how the compaction rulerepresents material deformation.The 3-D model is implemented using the generic finite element method framework Deal II,which provides tools, building on p4est and interfacing to PETSc, for the massively parallel distributedsolution to the model equations [2]. Experiments are being run on the Juelich Supercomputing Center'sJureca cluster. [1] McGovern, et.al. (2017). Novel basin modelling concept for simulating deformation from mechanical compaction using level sets. Computational Geosciences, SI:ECMOR XV, 1-14.[2] Bangerth, et. al. (2011). Algorithms and data structures for massively parallel generic adaptive finite element codes. ACM Transactions on Mathematical Software (TOMS), 38(2):14.

[A study of the occupational stress norm and it' s application for the technical group and scientific research group].

PubMed

Yang, Xin-wei; Liu, Ze-jun; Zhao, Pei-qing; Bai, Shao-ying; Pang, Xing-huo; Wang, Zhi-ming; Jin, Tai-yi; Lan, Ya-jia

2006-11-01

A study of the occupational stress norm and it' s application for the technical group and scientific research group. In this study, cross-sectional study method is used, and a synthetic way of sorting and randomized sampling is adopted to deal with research targets(235 scientific research group, 857 technical group). Descriptive statistics for OSI-R scale scores for the technical group and scientific research group were modulated. Scale raw score to T-score conversion tables derived from the OSI-R normative sample for technical group and scientific research group were established. OSI-R profile from for technical group and scientific research group were established. For the ORQ and PSQ scales, scores at or above 70T indicate a strong levels of maladaptive stress and strain. Score in the range of 60T to 69T suggest middle levels of maladaptive stress and strain. Score in the range of 40T to 59T indicate normal levels of stress and strain. Score below 40T indicate a relative absence of occupational stress and strain. For the PRQ scales, score below 30T indicate a significant lack of coping resources. Score in the range of 30T to 39T suggest middle deficits in coping resources. Score in the range of 40T to 59T indicate average coping resources. Scores at or above 60T indicate a strong levels of coping resources. Different intervention measure should be take to reduce the occupational stress so as to improve the work ability.

Proteomic Adaptations to Starvation Prepare Escherichia coli for Disinfection Tolerance

PubMed Central

Du, Zhe; Nandakumar, Renu; Nickerson, Kenneth; Li, Xu

2015-01-01

Despite the low nutrient level and constant presence of secondary disinfectants, bacterial re-growth still occurs in drinking water distribution systems. The molecular mechanisms that starved bacteria use to survive low-level chlorine-based disinfectants are not well understood. The objective of this study is to investigate these molecular mechanisms at the protein level that prepare starved cells for disinfection tolerance. Two commonly used secondary disinfectants chlorine and monochloramine, both at 1 mg/L, were used in this study. The proteomes of normal and starved Escherichia coli (K12 MG1655) cells were studied using quantitative proteomics. Over 60-min disinfection, starved cells showed significantly higher disinfection tolerance than normal cells based on the inactivation curves for both chlorine and monochloramine. Proteomic analyses suggest that starvation may prepare cells for the oxidative stress that chlorine-based disinfection will cause by affecting glutathione metabolism. In addition, proteins involved in stress regulation and stress responses were among the ones up-regulated under both starvation and chlorine/monochloramine disinfection. By comparing the fold changes under different conditions, it is suggested that starvation prepares E. coli for disinfection tolerance by increasing the expression of enzymes that can help cells survive chlorine/monochloramine disinfection. Protein co-expression analyses show that proteins in glycolysis and pentose phosphate pathway that were up-regulated under starvation are also involved in disinfection tolerance. Finally, the production and detoxification of methylglyoxal may be involved in the chlorine-based disinfection and cell defense mechanisms. PMID:25463932

Impact of oral cadmium intoxication on levels of different essential trace elements and oxidative stress measures in mice: a response to dose.

PubMed

Kumar, Narendra; Kumari, Vandna; Ram, Chand; Bharath Kumar, Bagepalli Sathyanarayana; Verma, Sunita

2018-02-01

The study evaluated the effect of oral intoxication of cadmium and the possible causes of oxidative stress and its preferential accumulation in different organs as well as sub-sequential effects in mice. Twenty-four Swiss albino male mice were divided into three groups viz., normal control group without cadmium chloride (CdCl 2 ), whereas a daily dose of 0.5 and 1.2 mg of CdCl 2 was orally administered for a period of a week to dose group 1 (DG-1) and dose group 2 (DG-2), respectively. A significant increase in the severity of cadmium toxicity was observed in animals as evidenced by aggravation in liver enzymes viz., serum alanine aminotransferase and aspartate transaminase, whereas lower levels of antioxidative stress markers in liver and kidney tissues of treated mice were observed as compared to normal control group. A significant depletion of calcium levels in liver tissues of DG-1 (217.36 ± 1.73 μg/g of wet tissues) and DG-2 (186.41 ± 1.56 μg/g of wet tissues) groups, along with Cd accumulation, was observed. To summarize, the current study would increase our understanding with respect to dose-dependent absorption of Cd and its toxicity led to mortality as well as adverse health effects in the body of mice. Graphical abstract ᅟ.

Proteomic adaptations to starvation prepare Escherichia coli for disinfection tolerance.

PubMed

Du, Zhe; Nandakumar, Renu; Nickerson, Kenneth W; Li, Xu

2015-02-01

Despite the low nutrient level and constant presence of secondary disinfectants, bacterial re-growth still occurs in drinking water distribution systems. The molecular mechanisms that starved bacteria use to survive low-level chlorine-based disinfectants are not well understood. The objective of this study is to investigate these molecular mechanisms at the protein level that prepare starved cells for disinfection tolerance. Two commonly used secondary disinfectants chlorine and monochloramine, both at 1 mg/L, were used in this study. The proteomes of normal and starved Escherichia coli (K12 MG1655) cells were studied using quantitative proteomics. Over 60-min disinfection, starved cells showed significantly higher disinfection tolerance than normal cells based on the inactivation curves for both chlorine and monochloramine. Proteomic analyses suggest that starvation may prepare cells for the oxidative stress that chlorine-based disinfection will cause by affecting glutathione metabolism. In addition, proteins involved in stress regulation and stress responses were among the ones up-regulated under both starvation and chlorine/monochloramine disinfection. By comparing the fold changes under different conditions, it is suggested that starvation prepares E. coli for disinfection tolerance by increasing the expression of enzymes that can help cells survive chlorine/monochloramine disinfection. Protein co-expression analyses show that proteins in glycolysis and pentose phosphate pathway that were up-regulated under starvation are also involved in disinfection tolerance. Finally, the production and detoxification of methylglyoxal may be involved in the chlorine-based disinfection and cell defense mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lipopolysaccharide-binding protein and leptin are associated with stress-induced interleukin-6 cytokine expression ex vivo in obesity.

PubMed

Huang, Chun-Jung; Stewart, Jennifer K; Shibata, Yoshimi; Slusher, Aaron L; Acevedo, Edmund O

2015-05-01

Obesity is associated with enhanced inflammation and mental stress, but limited information has addressed the potential additive effect of psychological stress on obesity-associated inflammation. This study examined whether obese subjects would elicit a greater host immune response (IL-6 mRNA and cytokine) to lipopolysaccharide (LPS) in response to mental stress. Blood samples for LPS-stimulated IL-6 mRNA and cytokine were collected prior to and following mental stress. Results showed that obese subjects elicited a greater LPS-induced IL-6 along with its mRNA expression following mental stress compared to normal-weight subjects. Stress-induced IL-6 cytokine response to LPS was correlated with the baseline levels of plasma LPS binding protein (LBP) and leptin. These findings are consistent with the idea that endogenous inflammatory agents (e.g., LBP and leptin), often elevated with obesity, enhance inflammatory responses to psychological stress. © 2014 Society for Psychophysiological Research.

Vitamin D3 contributes to enhanced osteogenic differentiation of MSCs under oxidative stress condition via activating the endogenous antioxidant system.

PubMed

Zhou, J; Wang, F; Ma, Y; Wei, F

2018-06-02

The anti-oxidative effects of vitamin D3 (Vd3) on mesenchymal stem cells (MSCs) have not been studied before. The present study suggested that Vd3 could not only promote the osteogenic differentiation of MSCs under normal condition but also partly protect it from oxidative stress damage by activating the endogenous antioxidant system. Evolving evidence proved that oxidative stress caused by reactive oxygen species (ROS) overproduction might lead to bone loss. Vd3, a commonly used osteogenic induction drug, was proved to exhibit potent anti-oxidative effects on other cell types. The present study aims to investigate the protective effects of Vd3 on oxidative stress-induced dysfunctions of MSCs, as well as its underlying mechanisms. The H 2 O 2 was used as exogenous reactive oxygen species (ROS). The influence of ROS and anti-oxidative protection of Vd3 on MSCs were analyzed too. Multi-techniques were used to assess the beneficial effects of Vd3 on MSCs under oxidative stress condition. The results demonstrated that Vd3 could significantly attenuate the H 2 O 2 -induced cell injury of MSCs via Sirt1/FoxO1 signaling pathway, and reduced the H 2 O 2 exposure-induced intracellular oxidative stress status of MSCs. What's more, the H 2 O 2 exposure resulted in the decreased osteogenic differentiation of MSCs, as evidenced by decreased alkaline phosphatase activity, calcium deposition level, and osteogenic differentiation gene mRNA levels, but the injury was restored via Vd3 administration. The results suggested that Vd3 could not only promote the osteogenic differentiation of osteoblastic cells under normal condition but also partly protect the cell from oxidative stress damage by activating endogenous antioxidant system. The study shed light on the new roles of Vd3 in bone modeling and remodeling regulation.

Dietary Pyridoxine Protects against Stress and Maintains Immunohaematological Status in Chanos chanos Exposed to Endosulfan.

PubMed

Kumar, Neeraj; Ambasankar, Kondusamy; Krishnani, Kishore Kumar; Bhushan, Shashi; Minhas, Paramjit Singh

2016-09-01

The amelioration effect of water-soluble vitamin pyridoxine against stress was evaluated in milkfish, Chanos chanos exposed to endosulfan. Two hundred and twenty-five fish were distributed randomly into five treatments, each with three replicates. Four isocaloric and isonitrogenous diets with graded levels of pyridoxine feed were as follows: normal water and fed with control diet (En0/PY0); endosulfan-treated water and fed with control diet (En/PY0); and endosulfan-treated water and fed with 50 (En/PY 50 mg/kg), 75 (En/PY 75 mg/kg) and 100 mg/kg (En/PY 100 mg/kg) pyridoxine-supplemented feed. The endosulfan in treated water was maintained at a level of 1/40th of LC50 (0.52 ppb). The effect of dietary pyridoxine supplementation was studied in terms of antioxidative enzymes (catalase, superoxide dismutase, glutathione-S-transferase), stress markers [heat-shock protein 70, caspase-3, cortisol, acetylcholine esterase (AChE), blood glucose], immunohaematological parameters (total protein, albumin, globulin and A/G ratio, nitroblue tetrazolium, RBC, WBC, Hb), gill histopathology and a subsequent challenge study with Vibrio parahaemolyticus. The antioxidative enzymes, stress markers, albumin and A/G ratio were significantly (p < 0.01) elevated, brain AChE and immunohaematological parameters were significantly (p < 0.01) decreased, and chromosome aberration and gill histopathology were also altered due to endosulfan exposure. The relative survival % was reduced due to the combined effect of endosulfan stress and bacterial challenge. Fish fed the diet supplemented with pyridoxine at 75 and 100 mg/kg was found to restore the studied parameter towards normal compared with control and indicated protection against endosulfan-induced stress significantly (p < 0.01). Results obtained in the present study indicate that the supplementation of 75 and 100 mg/kg of pyridoxine in the diet has a definitive role in the mitigation of the endosulfan-induced stress in milkfish, C. chanos fingerlings. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Intra-renal delivery of mesenchymal stem cells attenuates myocardial injury after reversal of hypertension in porcine renovascular disease.

PubMed

Eirin, Alfonso; Zhu, Xiang-Yang; Ferguson, Christopher M; Riester, Scott M; van Wijnen, Andre J; Lerman, Amir; Lerman, Lilach O

2015-01-19

Percutaneous transluminal renal angioplasty (PTRA) fails to fully improve cardiac injury and dysfunction in patients with renovascular hypertension (RVH). Mesenchymal stem cells (MSCs) restore renal function, but their potential for attenuating cardiac injury after reversal of RVH has not been explored. We hypothesized that replenishment of MSCs during PTRA would improve cardiac function and oxygenation, and decrease myocardial injury in porcine RVH. Pigs were studied after 16 weeks of RVH, RVH treated 4 weeks earlier with PTRA with or without adjunct intra-renal delivery of MSC (10^6 cells), and controls. Cardiac structure, function (fast-computed tomography (CT)), and myocardial oxygenation (Blood-Oxygen-Level-Dependent- magnetic resonance imaging) were assessed in-vivo. Myocardial microvascular density (micro-CT) and myocardial injury were evaluated ex-vivo. Kidney venous and systemic blood levels of inflammatory markers were measured and their renal release calculated. PTRA normalized blood pressure, yet stenotic-kidney glomerular filtration rate, similarly blunted in RVH and RVH + PTRA, normalized only in PTRA + MSC-treated pigs. PTRA attenuated left ventricular remodeling, whereas myocardial oxygenation, subendocardial microvascular density, and diastolic function remained decreased in RVH + PTRA, but normalized in RVH + PTRA-MSC. Circulating isoprostane levels and renal release of inflammatory cytokines increased in RVH and RVH + PTRA, but normalized in RVH + PTRA-MSC, as did myocardial oxidative stress, inflammation, collagen deposition, and fibrosis. Intra-renal MSC delivery during PTRA preserved stenotic-kidney function, reduced systemic oxidative stress and inflammation, and thereby improved cardiac function, oxygenation, and myocardial injury four weeks after revascularization, suggesting a therapeutic potential for adjunctive MSC delivery to preserve cardiac function and structure after reversal of experimental RVH.

Lowering Effects of Onion Intake on Oxidative Stress Biomarkers in Streptozotocin-Induced Diabetic Rats

PubMed Central

Azuma, Keiko; Minami, Yuko; Ippoushi, Katsunari; Terao, Junji

2007-01-01

The protective effect of onion against oxidative stress in streptozotosin-induced diabetic rats was investigated in comparison with that of quercetin aglycone. We measured oxidative stress biomarkers involving the susceptibility of the plasma against copper ion-induced lipid peroxidation, which was estimated by the amounts of thiobarbituric acid-reactive substances (TBARS) and cholesteryl ester hydroperoxides, and urine TBARS and 8-hydroxydeoxyguanosine contents. After the 12-week feeding period, plasma glucose levels and these biomarkers increased in diabetic rats compared to normal rats. In diabetic rats fed a 6.0% onion diet (quercetin equivalent: 0.023%), quercetin metabolites accumulated in the plasma at concentrations of approximately 35 µM. Onion intake decreased plasma glucose levels and lowered the oxidative stress biomarkers. On the other hand, quercetin metabolites in the plasma of rats fed a diet with 0.023% quercetin aglycone were found at lower concentrations (14.2 µM) than the rats fed the onion diet. Furthermore, oxidative stress biomarkers were higher in the quercetin diet group compared to the onion diet group. These results strongly suggest that onion intake suppresses diabetes-induced oxidative stress more effectively than the intake of the same amount of quercetin aglycone alone. PMID:18188415

Cortisol reactivity and emotional memory after psychosocial stress in oral contraceptive users.

PubMed

Mordecai, Kristen L; Rubin, Leah H; Eatough, Erin; Sundermann, Erin; Drogos, Lauren; Savarese, Antonia; Maki, Pauline M

2017-01-02

Oral contraceptive (OC) users typically show a blunted or no cortisol response to psychosocial stress. Although most OC regimens include both an inactive (dummy) and active pill phase, studies have not systematically investigated cortisol responses during these pill phases. Further, high levels of cortisol following a stressor diminish retrieval of emotional material, but the effects of stress on memory among OC users are poorly understood. We examined the effects of a psychosocial stressor, the Trier Social Stress Test, vs. a control condition on cortisol responsivity and emotional memory retrieval in women tested either during their active (n = 18) or inactive pill phase (n = 21). In secondary analyses, we quantitatively compared OC users with normally cycling women and showed a significant lack of cortisol response during both active and inactive pill phase. Emotional recall did not differ between active and inactive pill phases. Stress differentially diminished recall of negative words compared with positive or neutral words, but cortisol levels were unrelated to memory performance. These findings indicate that OC users have distinct cortisol and memory responses to stress that are similar between the active and inactive pill phases. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Early-life stress and the development of obesity and insulin resistance in juvenile bonnet macaques.

PubMed

Kaufman, Daniel; Banerji, Mary Ann; Shorman, Igor; Smith, Eric L P; Coplan, Jeremy D; Rosenblum, Leonard A; Kral, John G

2007-05-01

Stress is a risk factor for chronic illnesses such as obesity, type 2 diabetes, and hypertension and has been postulated to cause the metabolic syndrome via perturbation of the hypothalamo-pituitary-adrenal (HPA) axis. In our model of early-life stress (variable foraging demand [VFD]), food insecurity is imposed on monkey mothers for 16 weeks beginning when their nursing offspring are 3-5 months of age. Under VFD, food availability is never restricted, and the infant's growth is unaffected. VFD rearing does, however, cause a range of neurobiological abnormalities, including dysregulation of the HPA axis, manifested in abnormal cerebrospinal fluid cortisol and corticotropin-releasing factor levels. We previously reported spontaneous occurrence of metabolic syndrome in 14% of normally reared peripubertal bonnet macaques given ad libitum access to standard monkey chow. Here, we show that compared with normally reared monkeys, peripubertal VFD juveniles exhibit greater weight, BMI, abdominal circumference, and glucagon-like peptide-1 and decreased glucose disposal rates during hyperinsulinemic-euglycemic clamps. Our data suggest that early-life stress during a critical period of neuro development can result in the peripubertal emergence of obesity and insulin resistance.

Glucose metabolism in different regions of the rat brain under hypokinetic stress influence

NASA Technical Reports Server (NTRS)

Konitzer, K.; Voigt, S.

1980-01-01

Glucose metabolism in rats kept under long term hypokinetic stress was studied in 7 brain regions. Determination was made of the regional levels of glucose, lactate, glutamate, glutamine, aspartate, gamma-aminobutyrate and the incorporation of C-14 from plasma glucose into these metabolites, in glycogen and protein. From the content and activity data the regional glucose flux was approximated quantitatively. Under normal conditions the activity gradient cortex and frontal pole cerebellum, thalamus and mesencephalon, hypothalamus and pons and medulla is identical with that of the regional blood supply (measured with I131 serum albumin as the blood marker). Within the first days of immobilization a functional hypoxia occurred in all brain regions and the utilization of cycle amino acids for protein synthesis was strongly diminished. After the first week of stress the capillary volumes of all regions increased, aerobic glucose metabolism was enhanced (factors 1.3 - 2.0) and the incorporation of glucose C-14 via cycle amino acids into protein was considerably potentiated. The metabolic parameters normalized between the 7th and 11th week of stress. Blood supply and metabolic rate increased most in the hypothalamus.

L.D.V. measurements of unsteady flow fields in radial turbine

NASA Astrophysics Data System (ADS)

Tabakoff, W.; Pasin, M.

1992-07-01

Detailed measurements of an unsteady flow field within the inlet guide vanes (IGV) and the rotor of a radial inflow turbine were performed using a three component Laser Doppler Velocimeter (LDV) system together with a rotary encoder. The mean velocity, the flow angle and the turbulence contours for IGV passages are presented at four blade-to-blade planes for different rotor positions to give three dimensional, unsteady behavior of the IGV flow field. These results are compared with the measurements obtained in the same passage in the absence of the rotor. The flow field of the IGV passage was found to be affected by the presence of the rotor. The ratio of the tangential normal stresses to the radial normal stresses at the exit of the IGV was found to be more than doubled when compared to the case without the rotor. The rotor flow field measurements are presented as relative mean velocity and turbulence stress contours at various cross section planes throughout the rotor. The cross flow and turbulence stress levels were found to be influenced by the incidence angle. Transportation of the high turbulence fluid by the cross flow was observed downstream in the rotor blade passages.

Adrenocorticotrophic Hormone Levels in Ground Based Studies

NASA Technical Reports Server (NTRS)

Campbell, B. O.

1972-01-01

Baseline values of immunoreactive ACTH were established in the normal healthy adult. Normal levels of ACTH secretion were determined for both the male and the female in circulating plasma and serum. The data obtained in these studies are particularly significant in that the sampling was carefully controlled; only healthy employed individuals of both sexes were tested in a routine work situation that would not be considered conducive to stress. It has been found that alterations in the classically described circadian rhythm of ACTH secretion can occur when activities (such as work/rest cycles) are imposed on the individual studied. These changes can be demonstrated even when there is no appreciable change noted in the rhythm of hydrocortisone secretion.

PprM is necessary for up-regulation of katE1, encoding the major catalase of Deinococcus radiodurans, under unstressed culture conditions.

PubMed

Jeong, Sun-Wook; Seo, Ho Seong; Kim, Min-Kyu; Choi, Jong-Il; Lim, Heon-Man; Lim, Sangyong

2016-06-01

Deinococcus radiodurans is a poly-extremophilic organism, capable of tolerating a wide variety of different stresses, such as gamma/ultraviolet radiation, desiccation, and oxidative stress. PprM, a cold shock protein homolog, is involved in the radiation resistance of D. radiodurans, but its role in the oxidative stress response has not been investigated. In this study, we investigated the effect of pprM mutation on catalase gene expression. pprM disruption decreased the mRNA and protein levels of KatE1, which is the major catalase in D. radiodurans, under normal culture conditions. A pprM mutant strain (pprM MT) exhibited decreased catalase activity, and its resistance to hydrogen peroxide (H2O2) decreased accordingly compared with that of the wild-type strain. We confirmed that RecG helicase negatively regulates katE1 under normal culture conditions. Among katE1 transcriptional regulators, the positive regulator drRRA was not altered in pprM (-), while the negative regulators perR, dtxR, and recG were activated more than 2.5-fold in pprM MT. These findings suggest that PprM is necessary for KatE1 production under normal culture conditions by down-regulation of katE1 negative regulators.

Mesoporosity as a new parameter for understanding tension stress generation in trees.

PubMed

Chang, Shan-Shan; Clair, Bruno; Ruelle, Julien; Beauchêne, Jacques; Di Renzo, Francesco; Quignard, Françoise; Zhao, Guang-Jie; Yamamoto, Hiroyuki; Gril, Joseph

2009-01-01

The mechanism for tree orientation in angiosperms is based on the production of high tensile stress on the upper side of the inclined axis. In many species, the stress level is strongly related to the presence of a peculiar layer, called the G-layer, in the fibre cell wall. The structure of the G-layer has recently been described as a hydrogel thanks to N(2) adsorption-desorption isotherms of supercritically dried samples showing a high mesoporosity (pores size from 2-50 nm). This led us to revisit the concept of the G-layer that had been, until now, only described from anatomical observation. Adsorption isotherms of both normal wood and tension wood have been measured on six tropical species. Measurements show that mesoporosity is high in tension wood with a typical thick G-layer while it is much less with a thinner G-layer, sometimes no more than normal wood. The mesoporosity of tension wood species without a G-layer is as low as in normal wood. Not depending on the amount of pores, the pore size distribution is always centred around 6-12 nm. These results suggest that, among species producing fibres with a G-layer, large structural differences of the G-layer exist between species.

History of cigarette smoking in cognitively-normal elders is associated with elevated cerebrospinal fluid biomarkers of oxidative stress.

PubMed

Durazzo, Timothy C; Mattsson, Niklas; Weiner, Michael W; Korecka, Magdalena; Trojanowski, John Q; Shaw, Leslie M

2014-09-01

Cigarette smoking in adults is associated with abnormalities in brain neurobiology. Smoking-induced central nervous system oxidative stress (OxS) is a potential mechanism associated with these abnormalities. The goal of this study was to compare cognitively-normal elders on cerebrospinal fluid (CSF) levels of F2-isoprostane biomarkers of OxS. Elders with a lifetime history of smoking (smokers; n=50; 75±5 years of age; 34±28 pack-years; approximately 12% were actively smoking at the time of study) were compared to never-smokers (n=61; 76±6 years of age) on CSF iPF2α-III and 8,12, iso-iPF2α-VI F2-isoprostanes levels. F2-isoprostanes levels were quantitated with HPLC-atmospheric pressure chemical ionization-tandem mass spectrometry. Associations between F2-isoprostanes levels, hippocampal volumes, and cigarette exposure measures were also evaluated. Smokers showed higher iPF2α-III level than never-smokers. An age×smoking status interaction was observed for 8,12, iso-iPF2α-VI, where smokers demonstrate a significantly greater concentration with increasing age than never-smokers. In smokers only, higher 8,12, iso-iPF2α-VI concentration was associated with smaller hippocampal volume, and greater iPF2α-III level was related to greater pack years. This is the first study to demonstrate that a history of cigarette smoking in cognitively-normal elders was associated with significantly elevated CSF F2-isoprostane levels and greater age-related increases in F2-isoprostanes, and that higher F2-isoprostane levels in smokers were related to smaller hippocampal volume. These findings provide additional novel evidence that a history of chronic smoking during adulthood is associated with adverse effects on the human brain that are potentially enduring even with extended smoking cessation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of Two Different Doses of Dexmedetomidine on Stress Response in Laparoscopic Pyeloplasty: A Randomized Prospective Controlled Study.

PubMed

Shamim, Rafat; Srivastava, Shashi; Rastogi, Amit; Kishore, Kamal; Srivastava, Aneesh

2017-01-01

Clonidine, opioids, β-blockers, and dexmedetomidine have been tried to attenuate stress responses during laparoscopic surgery. We evaluated the efficacy of dexmedetomidine in two different doses in attenuating stress responses on patients undergoing laparoscopic pyeloplasty. Ninety patients were assigned to one of the three groups: Group A, Group B, and Group C. Group B received dexmedetomidine 1 mcg/kg as loading dose, followed by 0.7 mcg/kg/h for maintenance; Group C received dexmedetomidine 0.7 mcg/kg as a loading dose, followed by 0.5 mcg/kg/h for maintenance. Group A received normal saline. Stress responses were assessed by the variations in heart rate (HR), mean arterial pressure (MAP), blood glucose levels, and serum cortisol levels. One-way analysis of variance test was applied. Multiple comparisons between groups were done with post hoc Bonferroni test. The HR and MAP were found to be higher in Group A. The difference was statistically significant ( P < 0.05) during intubation, carbon dioxide insufflation, and extubation when compared with Groups B and C. Blood glucose levels at postintubation and at extubation were higher in Group A and statistically significant ( P < 0.05) when compared with Groups B and C. Serum cortisol levels at postintubation, during midsurgery, and 2 h after extubation were higher in Group A and statistically significant ( P < 0.05) when compared with Groups B and C. However, HR, MAP, blood glucose levels, and serum cortisol levels were similar in dexmedetomidine groups. Dexmedetomidine decreases stress response and provides good condition for maintenance of anesthesia. Dexmedetomidine when used in lower dose in Group C decreases stress response comparable to higher dose in Group B.

Comparisons of the oxidative stress biomarkers levels in gestational diabetes mellitus (GDM) and non-GDM among Thai population: cohort study.

PubMed

Rueangdetnarong, Hathairat; Sekararithi, Rattanaporn; Jaiwongkam, Thidarat; Kumfu, Sirinart; Chattipakorn, Nipon; Tongsong, Theera; Jatavan, Phudit

2018-05-01

The primary objective of this study was to compare the levels of oxidative stress biomarkers between pregnancies with gestational diabetes mellitus (GDM) and normoglycemic pregnancies. A prospective study was conducted on pregnant women at average risk for GDM. The participants were screened for GDM with glucose challenge test and confirmed by 100 g, 3-h oral glucose tolerance test and categorized into the control (non-GDM) and GDM groups. Maternal blood was collected from all participants at gestational age (GA) 24-28 weeks and early labor and fetal cord blood was collected for measurements of 8 Isoprostane (8Isop) (oxidative stress marker), TNF-α (inflammatory marker) and IL-10 (anti-inflammatory marker) and were followed up for maternal and neonatal outcomes. A total of 62 women, 30 in GDM and 32 in control group, met the inclusion criteria. At 24-28 weeks of gestation, maternal serum 8Isop and TNF-α levels were significantly higher in GDM group ( P  = 0.032 and P  = 0.047), in spite of good glycemic control. At early labor, maternal 8Isop levels were significantly higher in GDM ( P  = 0.001). The biomarkers in the cord blood as well as maternal and neonatal outcomes in both groups were not significantly different. GDM is significantly associated with inflammatory process when compared to normal pregnancy, as indicated by higher oxidative stress and apoptosis markers. However, such levels were not correlated with the pregnancy outcomes. An increase in oxidative stress could not be prevented by good glycemic control. Cord blood biomarker levels in pregnancy with GDM were not changed, suggesting that the placenta could be the barrier for the oxidative stress and cytokines. © 2018 The authors.

[Study on the occupational stress norm and it's application for the marketing group, public service/safety group and production laborer group].

PubMed

Yang, Xin-Wei; Wang, Zhi-Ming; Jin, Tai-Yi; Lan, Ya-Jia

2006-09-01

A study of the occupational stress norm and it's application for the marketing group, public service/safety group and production laborer group. In this study, cross-sectional study method is used, and a synthetic way of sorting and randomized sampling is adopted to deal with research targets (36 marketing group, 331 public service/safety group, 903 production laborer group). Descriptive statistics for OSI-R scale scores for the marketing group, public service/safety group and production laborer group were modulated. Scale raw score to T-score conversion tables derived from the OSI-R normative sample for marketing group public service/safety group and production laborer group were established. OSI-R profile from for marketing group, public service/safety group and production laborer group were established. For the ORQ and PSQ scales, scores at or above 70 indicate a strong levels of maladaptive stress and strain. Score in the range of 60 to 69 suggest middle levels of maladaptive stress and strain. Score in the range of 40 to 59 indicate normal levels of stress and strain. Score below 40 indicate a relative absence of occupational stress and strain. For the PRQ scales, score below 30 indicate a significant lack of coping resources. Score in the range of 30 to 39 suggest middle deficits in coping resources. Score in the range of 40 to 59 indicate average coping resources. Scores at or above 60 indicate a strong levels of coping resources. The authors combined subjective and objective environment match model of occupational stress. Different intervention measure should be take to reduce the occupational stress so as to improve the work ability.

Childhood socioeconomic status and serotonin transporter gene polymorphism enhance cardiovascular reactivity to mental stress.

PubMed

Williams, Redford B; Marchuk, Douglas A; Siegler, Ilene C; Barefoot, John C; Helms, Michael J; Brummett, Beverly H; Surwit, Richard S; Lane, James D; Kuhn, Cynthia M; Gadde, Kishore M; Ashley-Koch, Allison; Svenson, Ingrid K; Schanberg, Saul M

2008-01-01

To test the hypothesis that low socioeconomic status (SES) and the 5HTTLPR L allele are associated with increased cardiovascular reactivity (CVR) to stress in a larger sample and that SES and 5HTTLPR genotypes interact to enhance CVR to stress. CVR to mental stress has been proposed as one mechanism linking stress to the pathogenesis of cardiovascular disease. The more transcriptionally efficient long (L) allele of a polymorphism of the serotonin transporter gene promoter (5HTTLPR) has been found associated with increased risk of myocardial infarction. We found the long allele associated with larger CVR to mental stress in a preliminary study of 54 normal volunteers. Subjects included 165 normal community volunteers stratified for race, gender, and SES, who underwent mental stress testing. Childhood SES as indexed by Father's Education Level was associated with larger systolic blood pressure (SBP) (p < .05) and diastolic blood pressure (DBP) (p = .01) responses to mental stress. The L allele was associated with larger SBP (p = .04), DBP (p < .0001), and heart rate (p = .04) responses to mental stress compared with the short (S) allele. Subjects with the SS genotype and high Father's Education exhibited smaller SBP (5.2 mm Hg) and DBP (2.9 mm Hg) responses than subjects with LL genotype and low Father's Education (SBP = 13.3 mm Hg, p = .002; DBP = 9.7 mm Hg, p < .0001). Both the 5HTTLPR long allele and low SES, particularly during childhood, are associated with increased CVR to mental stress, which could account, at least in part, for the increased cardiovascular disease risk associated with these characteristics. If confirmed in further research, these characteristics could be used to identify persons who might benefit from preventive interventions.

Daily exercise prevents diastolic dysfunction and oxidative stress in a female mouse model of western diet induced obesity by maintaining cardiac heme oxygenase-1 levels.

PubMed

Bostick, Brian; Aroor, Annayya R; Habibi, Javad; Durante, William; Ma, Lixin; DeMarco, Vincent G; Garro, Mona; Hayden, Melvin R; Booth, Frank W; Sowers, James R

2017-01-01

Obesity is a global epidemic with profound cardiovascular disease (CVD) complications. Obese women are particularly vulnerable to CVD, suffering higher rates of CVD compared to non-obese females. Diastolic dysfunction is the earliest manifestation of CVD in obese women but remains poorly understood with no evidence-based therapies. We have shown early diastolic dysfunction in obesity is associated with oxidative stress and myocardial fibrosis. Recent evidence suggests exercise may increase levels of the antioxidant heme oxygenase-1 (HO-1). Accordingly, we hypothesized that diastolic dysfunction in female mice consuming a western diet (WD) could be prevented by daily volitional exercise with reductions in oxidative stress, myocardial fibrosis and maintenance of myocardial HO-1 levels. Four-week-old female C57BL/6J mice were fed a high-fat/high-fructose WD for 16weeks (N=8) alongside control diet fed mice (N=8). A separate cohort of WD fed females was allowed a running wheel for the entire study (N=7). Cardiac function was assessed at 20weeks by high-resolution cardiac magnetic resonance imaging (MRI). Functional assessment was followed by immunohistochemistry, transmission electron microscopy (TEM) and Western blotting to identify pathologic mechanisms and assess HO-1 protein levels. There was no significant body weight decrease in exercising mice, normalized body weight 14.3g/mm, compared to sedentary mice, normalized body weight 13.6g/mm (p=0.38). Total body fat was also unchanged in exercising, fat mass of 6.6g, compared to sedentary mice, fat mass 7.4g (p=0.55). Exercise prevented diastolic dysfunction with a significant reduction in left ventricular relaxation time to 23.8ms for exercising group compared to 33.0ms in sedentary group (p<0.01). Exercise markedly reduced oxidative stress and myocardial fibrosis with improved mitochondrial architecture. HO-1 protein levels were increased in the hearts of exercising mice compared to sedentary WD fed females. This study provides seminal evidence that exercise can prevent diastolic dysfunction in WD-induced obesity in females even without changes in body weight. Furthermore, the reduction in myocardial oxidative stress and fibrosis and improved HO-1 levels in exercising mice suggests a novel mechanism for the antioxidant effect of exercise. Copyright © 2016 Elsevier Inc. All rights reserved.

Psychological stress alters the ultrastructure and increases IL-1β and TNF-α in mandibular condylar cartilage

PubMed Central

Lv, Xin; Li, Qiang; Wu, Shun; Sun, Jing; Zhang, Min; Chen, Yong-Jin

2012-01-01

Psychological factors can be correlated with temporomandibular disorders (TMDs), but the mechanisms are unknown. In the present study, we examined the microstructural changes and expression of proinflammatory cytokines in mandibular condylar cartilage of the temporomandibular joint (TMJ) in a psychological stress animal model. Male Sprague-Dawley rats (8 weeks old, 210 ± 10 g) were randomly divided into 3 groups: psychological stress (PS, N = 48), foot shock (FS, N = 24), and control (N = 48). After inducing psychological stress using a communication box with the FS rats for 1, 3, or 5 weeks, PS rats were sacrificed and compared to their matched control littermates, which received no stress and were killed at the same times as the PS rats. Body and adrenal gland weight were measured and corticosterone and adrenocorticotropic hormone levels were determined by radioimmunoassay. After hematoxylin-eosin staining for histological observation, the ultrastructure of the TMJ was examined by scanning electron microscopy. Transcription and protein levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were evaluated by ELISA and semi-quantitative RT-PCR. The PS group showed a significantly higher adrenal gland weight after 3 weeks of stress and higher hormone levels at weeks 1, 3, and 5. Histopathological changes and thinning cartilage were apparent at weeks 3 and 5. In the PS group, TNF-α increased at 1, 3, and 5 weeks and IL-1β increased significantly after 1 and 3 weeks of stress, and then decreased to normal levels by 5 weeks. Psychological stress increased plasma hormone levels and RT-PCR indicated increased IL-1β and TNF-α expression in the TMJ in a time-dependent manner. These results suggest that cytokine up-regulation was accompanied by stress-induced cartilage degeneration in the mandibular condyle. The proinflammatory cytokines play a potential role in initiating the cartilage destruction that eventually leads to the TMDs. PMID:22714807

Effects of Weight Reduction After Sleeve Gastrectomy on Metabolic Variables in Saudi Obese Subjects in Aseer Province of Kingdom of Saudi Arabia.

PubMed

Bawahab, Mohammed A; Assiri, Abdullah S; Maksoud, Walid Abdel; Patel, Ayyub; Kadoumi, Osama; Zaman, Gaffar Sarwar; Alessih, Riyad Mohammed Khalil; Haider, Syed Saleem

2017-08-01

The objectives of this study were to investigate the occurrence of oxidative stress, status of protective antioxidants enzymes, inflammatory biomarkers, and some metabolic health variables in the blood and to compare the results between those of the normal controls and obese patients submitted to sleeve gastrectomy-induced weight loss over a 1-year follow-up period. A prospective study was conducted in Aseer Central Hospital and Abha Private Hospital in the Kingdom of Saudi Arabia from January 2012 to January 2013 on 50 normal (BMI = 22-25 kg/m 2 ) control subjects and 50 obese (BMI = 45-50 kg/m 2 ) patients. A subset of 20 men and 80 women patients, aged 20-45 years, was included. The systemic blood cell counts were determined by Beckman Coulter UniCel analyzer. The occurrence of oxidative stress, the status of antioxidant enzyme system in the blood, levels of serum hepatic enzymes, cardiovascular risk factors, and serum sodium, potassium, copper, and zinc levels were determined by spectrophotometric procedures. The concentration of TSH and T 4 were analyzed by Siemens Immunoassay System. Group 1 (Obese: preoperative) This group compared with the normal controls exhibited significant (p < 0.05) increase in inflammatory biomarkers, a significant (p < 0.05) rise in hepatic enzymes, a significant (p < 0.05) decrease in serum total bilirubin. Concentration of serum total cholesterol (TC), triacylglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and fasting blood glucose(FBG) were significantly (p < 0.05) increased, but HDL cholesterol (HDL-C) was significantly depleted (p < 0.05). Serum urea and creatinine contents were significantly (p < 0.05) decreased. Serum copper and zinc levels were significantly (p < 0.05) increased. Group 2: Sleeve Gastrectomy Surgery (Obese: postoperative) This group compared with the obese group, preoperatively, demonstrated a profound reduction in body weight (-32%) as well as in BMI (-29%). Serum malondialdehyde, a stress index, was significantly (p < 0.001) inhibited and conversely, activities of antioxidant enzymes: superoxide dismutase(Cu-Zn SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PDH), and vitamin C, were remarkably (p < 0.001) increased. Furthermore, remarkable improvements in deranged metabolic variables approaching normality were discernible. Inflammatory biomarkers in the blood and hepatic enzymes in serum were significantly (p < 0.001) decreased. Levels of TC, TG, LDL-C, FBG, and HDL-C in serum exhibited significant (p < 0.05) reductions, a reversal toward normality. Serum albumin and total bilirubin concentrations were significantly increased (p < 0.001). Serum sodium, potassium, copper, zinc, and TSH levels were significantly (p < 0.001) decreased. Obesity is a chronic disease of multifactorial origin and resulted in perturbations of whole body metabolism in this study. It is thus likely that this imbalance was associated with an inhibition in protective antioxidants and occurrence of oxidative stress. The staging concept of sleeve gastrectomy is a safe and effective approach with remarkable efficacy in sustaining weight loss and bringing back normal metabolism of variables in tissues over a 1-year follow-up period.

Boron attenuates malathion-induced oxidative stress and acetylcholinesterase inhibition in rats.

PubMed

Coban, Funda Karabag; Ince, Sinan; Kucukkurt, Ismail; Demirel, Hasan Huseyin; Hazman, Omer

2015-10-01

Organophosphorus compounds cause oxidative stress and lead to alterations in antioxidant status in organisms. In this study, the effects of subchronic exposure to malathion and the protective effects of boron (B) were evaluated in 48 Wistar rats, which were divided equally into six groups. For 28 d, the control group received a normal diet and tap water, the corn oil group received a normal diet and 0.5 mL of corn oil by gastric gavage and the malathion group received a normal diet and malathion (100 mg/kg/d) by gastric gavage. During the same period, each of the three other groups received a different dosage of B (5, 10 and 20 mg/kg/d, respectively) and malathion (100 mg/kg/d) by gastric gavage. Malathion administration during the period increased malondialdehyde, nitric oxide and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, as well as markers of liver function, yet decreased acetylcholinesterase, reduced glutathione, superoxide dismutase, and catalase activities in blood, liver, kidney and brain tissues. Administration of B in a dose-dependent manner also reversed malathion-induced oxidative stress, lipid peroxidation (LPO) and antioxidant enzyme activity. Moreover, B exhibited protective action against malathion-induced histopathological changes in liver, kidney and brain tissues. These results demonstrate that, if used in a dose-dependent manner, B decreases malathion-induced oxidative stress, enhances the antioxidant defense mechanism and regenerates tissues in rats.

Nucleation and triggering of earthquake slip: effect of periodic stresses

USGS Publications Warehouse

Dieterich, J.H.

1987-01-01

Results of stability analyses for spring and slider systems, with state variable constitutive properties, are applied to slip on embedded fault patches. Unstable slip may nucleate only if the slipping patch exceeds some minimum size. Subsequent to the onset of instability the earthquake slip may propagate well beyond the patch. It is proposed that the seismicity of a volume of the earth's crust is determined by the distribution of initial conditions on the population of fault patches that nucleate earthquake slip, and the loading history acting upon the volume. Patches with constitutive properties inferred from laboratory experiments are characterized by an interval of self-driven accelerating slip prior to instability, if initial stress exceeds a minimum threshold. This delayed instability of the patches provides an explanation for the occurrence of aftershocks and foreshocks including decay of earthquake rates by time-1. A population of patches subjected to loading with a periodic component results in periodic variation of the rate of occurrence of instabilities. The change of the rate of seismicity for a sinusoidal load is proportional to the amplitude of the periodic stress component and inversely proportional to both the normal stress acting on the fault patches and the constitutive parameter, A1, that controls the direct velocity dependence of fault slip. Values of A1 representative of laboratory experiments indicate that in a homogeneous crust, correlation of earthquake rates with earth tides should not be detectable at normal stresses in excess of about 8 MPa. Correlation of earthquakes with tides at higher normal stresses can be explained if there exist inhomogeneities that locally amplify the magnitude of the tidal stresses. Such amplification might occur near magma chambers or other soft inclusions in the crust and possibly near the ends of creeping fault segments if the creep or afterslip rates vary in response to tides. Observations of seismicity rate variations associated with seasonal fluctuations of reservoir levels appear to be consistent with the model. ?? 1987.

Anti-Apoptotic Protein Bcl-xL Expression in the Midbrain Raphe Region Is Sensitive to Stress and Glucocorticoids

PubMed Central

Kalinina, Tatyana S.; Bulygina, Veta V.; Lanshakov, Dmitry A.; Babluk, Ekaterina V.

2015-01-01

Anti-apoptotic proteins are suggested to be important for the normal health of neurons and synapses as well as for resilience to stress. In order to determine whether stressful events may influence the expression of anti-apoptotic protein Bcl-xL in the midbrain and specifically in the midbrain serotonergic (5-HT) neurons involved in neurobehavioral responses to adverse stimuli, adult male rats were subjected to short-term or chronic forced swim stress. A short-term stress rapidly increased the midbrain bcl-xl mRNA levels and significantly elevated Bcl-xL immunoreactivity in the midbrain 5-HT cells. Stress-induced increase in glucocorticoid secretion was implicated in the observed effect. The levels of bcl-xl mRNA were decreased after stress when glucocorticoid elevation was inhibited by metyrapone (MET, 150 mg/kg), and this decrease was attenuated by glucocorticoid replacement with dexamethasone (DEX; 0.2 mg/kg). Both short-term stress and acute DEX administration, in parallel with Bcl-xL, caused a significant increase in tph2 mRNA levels and slightly enhanced tryptophan hydroxylase immunoreactivity in the midbrain. The increasing effect on the bcl-xl expression was specific to the short-term stress. Forced swim repeated daily for 2 weeks led to a decrease in bcl-xl mRNA in the midbrain without any effects on the Bcl-xL protein expression in the 5-HT neurons. In chronically stressed animals, an increase in tph2 gene expression was not associated with any changes in tryptophan hydroxylase protein levels. Our findings are the first to demonstrate that both short-term stress and acute glucocorticoid exposures induce Bcl-xL protein expression in the midbrain 5-HT neurons concomitantly with the activation of the 5-HT synthesis pathway in these neurons. PMID:26624017

Oxygen radical absorbance capacity (ORAC) and exercise-induced oxidative stress in trotters.

PubMed

Kinnunen, Susanna; Hyyppä, Seppo; Lehmuskero, Arja; Oksala, Niku; Mäenpää, Pekka; Hänninen, Osmo; Atalay, Mustafa

2005-12-01

Strenuous exercise is a potent inducer of oxidative stress, which has been suggested to be associated with disturbances in muscle homeostasis, fatigue and injury. There is no comprehensive or uniform view of the antioxidant status in horses. We have previously shown that moderate exercise induces protein oxidation in trotters. The aim of this study was to measure the antioxidative capacity of the horse in relation to different antioxidant components and oxidative stress markers after a single bout of moderate exercise to elucidate the mechanisms of antioxidant protection in horses. Eight clinically normal and regularly trained standard-bred trotters were treadmill-exercised for 53 min at moderate intensity. Blood samples were collected prior to and immediately after exercise and at 4 and 24 h of recovery. Muscle biopsies from the middle gluteal muscle were taken before exercise and after 4 h of recovery. Acute induction of oxygen radical absorbance capacity (ORAC) did not prevent exercise-induced oxidative stress, which was demonstrated by increased lipid hydroperoxides (LPO). Pre-exercise ORAC levels were, however, a determinant of total glutathione content of the blood after 4 and 24 h of recovery. Furthermore, baseline ORAC level correlated negatively with 4-h recovery LPO levels. Our results imply that horses are susceptible to oxidative stress, but a stronger antioxidant capacity may improve coping with exercise-induced oxidative stress.

The expression of heat shock proteins 70 and 90 in pea seedlings under simulated microgravity conditions

NASA Astrophysics Data System (ADS)

Kozeko, L.

Microgravity is an abnormal and so stress factor for plants. Expression of known stress-related genes is appeared to implicate in the cell response to different kinds of stress. Heat shock proteins HSP70 and HSP90 are present in plant cells under the normal growth conditions and their quantity increases during stress. The effect of simulated microgravity on expression of HSP70 and HSP90 was studied in etiolated Pisum sativum seedlings grown on the horizontal clinostat (2 rpm) from seed germination for 3 days. Seedlings were also subjected to two other types of stressors: vertical clinorotatoin (2 rpm) and 2 h temperature elevation (40°C). HSPs' level was measured by ELISA. The quantity of both HSPs increased more than in three times in the seedlings on the horizontal clinostat in comparison with the stationary 1 g control. Vertical clinorotation also increased HSPs' level but less at about 20% than horizontal one. These effects were comparable with the influence of temperature elevation. The data presented suggest that simulated microgravity upregulate HSP70 and HSP90 expression. The increased HSPs' level might evidence the important functional role of these proteins in plant adaptation to microgravity. We are currently investigating the contribution of constitutive or inducible forms of the HSPs in this stress response.

Linking megathrust earthquakes to brittle deformation in a fossil accretionary complex

PubMed Central

Dielforder, Armin; Vollstaedt, Hauke; Vennemann, Torsten; Berger, Alfons; Herwegh, Marco

2015-01-01

Seismological data from recent subduction earthquakes suggest that megathrust earthquakes induce transient stress changes in the upper plate that shift accretionary wedges into an unstable state. These stress changes have, however, never been linked to geological structures preserved in fossil accretionary complexes. The importance of coseismically induced wedge failure has therefore remained largely elusive. Here we show that brittle faulting and vein formation in the palaeo-accretionary complex of the European Alps record stress changes generated by subduction-related earthquakes. Early veins formed at shallow levels by bedding-parallel shear during coseismic compression of the outer wedge. In contrast, subsequent vein formation occurred by normal faulting and extensional fracturing at deeper levels in response to coseismic extension of the inner wedge. Our study demonstrates how mineral veins can be used to reveal the dynamics of outer and inner wedges, which respond in opposite ways to megathrust earthquakes by compressional and extensional faulting, respectively. PMID:26105966

The effect of bone growth onto massive prostheses collars in protecting the implant from fracture.

PubMed

Fromme, Paul; Blunn, Gordon W; Aston, William J; Abdoola, Tasneem; Koris, Jacob; Coathup, Melanie J

2017-03-01

Limb-sparing distal femoral endoprotheses used in cancer patients have a high risk of aseptic loosening. It had been reported that young adolescent patients have a higher rate of loosening and fatigue fracture of intramedullary stems because the implant becomes undersized as patients grow. Extracortical bone growth into the grooved hydroxyapatite-coated collar had been shown to reduce failure rates. The stresses in the implant and femur have been calculated from Finite Element models for different stages of bone growth onto the collar. For a small diameter stem without any bone growth, a large stress concentration at the implant shoulder was found, leading to a significant fracture risk under normal walking loads. Bone growth and osseointergration onto the implant collar reduced the stress level in the implant to safe levels. For small bone bridges a risk of bone fracture was observed. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Does medial tenderness predict deep deltoid ligament incompetence in supination-external rotation type ankle fractures?

PubMed

DeAngelis, Nicola A; Eskander, Mark S; French, Bruce G

2007-04-01

To identify whether medial tenderness is a predictor of deep deltoid ligament incompetence in supination-external rotation ankle fractures. All Weber B lateral malleolar fractures with normal medial clear space over a 9 month period were prospectively included in the study. Fracture patterns not consistent with a supination-external rotation mechanism were excluded. High-volume tertiary care referral center and Level I trauma center. Fifty-five skeletally mature patients with a Weber B lateral malleolar fracture and normal medial clear space presenting to our institution were included. All study patients had ankle anteroposterior, lateral, and mortise radiographs. Each patient was seen and evaluated by an orthopedic specialist and the mechanism of injury was recorded. Each patient was assessed for tenderness to palpation in the region of the deltoid ligament and then had an external rotation stress mortise radiograph. Correlating medial tenderness with deep deltoid competence as measured by stress radiographs. Thirteen patients (23.6%) were tender medially and had a positive external rotation stress radiograph. Thirteen patients (23.6%) were tender medially and had a negative external rotation stress radiograph. Nineteen patients (34.5%) were nontender medially and had a negative external rotation stress radiograph. Ten patients (18.2%) were nontender medially and had a positive external rotation stress radiograph. We calculated a chi statistic of 2.37 as well as the associated P value of 0.12. Medial tenderness as a measure of deep deltoid ligament incompetence had a sensitivity of 57%, a specificity of 59%, a positive predictive value of 50%, a negative predictive value of 66%, and an accuracy of 42%. There was no statistical significance between the presence of medial tenderness and deep deltoid ligament incompetence. There is a 25% chance of the fracture in question with medial tenderness having a positive external rotation stress and a 25% chance the fracture with no medial tenderness having a positive stress test. Medial tenderness in a Weber B lateral ankle fracture with a normal clear space on standard plain radiographs does not ensure the presence of a positive external rotation stress test.

Constraining friction, dilatancy and effective stress with earthquake rates in the deep crust

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Thomas, A.; Burgmann, R.; Shelly, D. R.

2015-12-01

Similar to their behavior on the deep extent of some subduction zones, families of recurring low-frequency earthquakes (LFE) within zones of non-volcanic tremor on the San Andreas fault in central California show strong sensitivity to stresses induced by the tides. Taking all of the LFE families collectively, LFEs occur at all levels of the daily tidal stress, and are in phase with the very small, ~200 Pa, shear stress amplitudes while being uncorrelated with the ~2 kPa tidal normal stresses. Following previous work we assume LFE sources are small, persistent regions that repeatedly fail during shear within a much larger scale, otherwise aseismically creeping fault zone and that the correlation of LFE occurrence reflects modulation of the fault creep rate by the tidal stresses. We examine the predictions of laboratory-observed rate-dependent dilatancy associated with frictional slip. The effect of dilatancy hardening is to damp the slip rate, so high dilatancy under undrained pore pressure reduces modulation of slip rate by the tides. The undrained end-member model produces: 1) no sensitivity to the tidal normal stress, as first suggested in this context by Hawthorne and Rubin [2010], and 2) fault creep rate in phase with the tidal shear stress. Room temperature laboratory-observed values of the dilatancy and friction coefficients for talc, an extremely weak and weakly dilatant material, under-predict the observed San Andreas modulation at least by an order of magnitude owing to too much dilatancy. This may reflect a temperature dependence of the dilatancy and friction coefficients, both of which are expected to be zero at the brittle-ductile transition. The observed tidal modulation constrains the product of the friction and dilatancy coefficients to be at most 5 x 10-7 in the LFE source region, an order of magnitude smaller than observed at room temperature for talc. Alternatively, considering the predictions of a purely rate-dependent talc friction would constrain the ambient effective normal stress to be no more than 40 kPa. In summary, for friction models that have both rate-dependent strength and dilatancy, the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid pressures.

Full-Scale Linear Cutting Tests in Chongqing Sandstone to Study the Influence of Confining Stress on Rock Cutting Forces by TBM Disc Cutter

NASA Astrophysics Data System (ADS)

Pan, Yucong; Liu, Quansheng; Liu, Jianping; Peng, Xingxin; Kong, Xiaoxuan

2018-06-01

In order to study the influence of confining stress on rock cutting forces by tunnel boring machine (TBM) disc cutter, full-scale linear cutting tests are conducted in Chongqing Sandstone (uniaxial compressive strength 60.76 MPa) using five equal biaxial confining stressed conditions, i.e. 0-0, 5-5, 10-10, 15-15 and 20-20 MPa; disc cutter normal force, rolling force, cutting coefficient and normalized resultant force are analysed. It is found that confining stress can greatly affect disc cutter resultant force, its proportion in normal and rolling directions and its acting point for the hard Chongqing Sandstone and the confining stress range used in this study. For every confining stressed condition, as cutter penetration depth increases, disc cutter normal force increases with decreasing speed, rolling force and cutting coefficient both increase linearly, and acting point of the disc cutter resultant force moves downward at some extent firstly and then upward back to its initial position. For same cutter penetration depth, as confining stress increases, disc cutter normal force, rolling force, cutting coefficient and normalized resultant force all increase at some extent firstly and then decrease rapidly to very small values (quite smaller than those obtained under the non-stressed condition) after some certain confining stress thresholds. The influence of confining stress on rock cutting by TBM disc cutter can be generally divided into three stages as confining stress increases, i.e. strengthening effect stage, damaging effect stage and rupturing effect stage. In the former two stages (under low confining stress), rock remains intact and rock cutting forces are higher than those obtained under the non-stressed condition, and thus rock cutting by TBM disc cutter is restrained; in the last stage (under high confining stress), rock becomes non-intact and rock slabbing failure is induced by confining stress before disc cutting, and thus rock cutting by TBM disc cutter is facilitated. Meanwhile, some critical values of confining stress and cutter penetration depth are identified to represent the changes of rock cutting state. This study provides better understanding of the influence of confining stress on disc cutter performance and can guide to optimize the TBM operation under stressed condition.

The impact of epilepsy on preschool children and their families.

PubMed

Tanriverdi, Müberra; Mutluay, Fatma Karantay; Tarakçi, Devrim; Güler, Serhat; Iscan, Akin

2016-09-01

This study investigated the possible presence of sensory-motor developmental impairments in preschool children with epilepsy and explored epilepsy impact on their activities and quality of life and on the stress load of their family. Study participants were children aged 2-6years diagnosed with epilepsy without any other comorbidities (epi-only children). The instruments used for assessment included the Neurological, Sensory, Motor, Developmental Assessment (NSMDA) scale for sensory-motor development, the Impact of Childhood Neurologic Disability Scale (ICNDS), and the Impact of Pediatric Epilepsy Scale (IPES) for disease impact on disability and Quality of Life (QoL), as well as the Pediatric Outcomes Data Collection Instrument (PODCI) for functional health status, and the Parental Stress Scale (PSS) for the family stress load. Required data were obtained from direct testing or observation of children's activities and mother-supplied answers to questions. Eighty-two children were investigated. The NSMDA scores were in the normal development range 6-8. Significant moderate impact of the disease on disability and QoL was estimated with the ICNDS and IPES instruments. The PODCI scores were similar to healthy population levels except for the happiness dimension which was better for children with epilepsy. PSS were significantly above normal. The functional health and QoL of the children as well as their family stress were found to be positively correlated with increasing age. It is found that epilepsy does not degrade neuromotor development and functional health status of preschool epi-only children, though it has a significant impact on their neurological disability and QoL and the stress level of their families; this impact seems to decrease with age. Copyright © 2016 Elsevier Inc. All rights reserved.

Biological stress systems, adverse life events and the onset of chronic multisite musculoskeletal pain: a 6-year cohort study.

PubMed

Generaal, Ellen; Vogelzangs, Nicole; Macfarlane, Gary J; Geenen, Rinie; Smit, Johannes H; de Geus, Eco J C N; Penninx, Brenda W J H; Dekker, Joost

2016-05-01

Dysregulated biological stress systems and adverse life events, independently and in interaction, have been hypothesised to initiate chronic pain. We examine whether (1) function of biological stress systems, (2) adverse life events, and (3) their combination predict the onset of chronic multisite musculoskeletal pain. Subjects (n=2039) of the Netherlands Study of Depression and Anxiety, free from chronic multisite musculoskeletal pain at baseline, were identified using the Chronic Pain Grade Questionnaire and followed up for the onset of chronic multisite musculoskeletal pain over 6 years. Baseline assessment of biological stress systems comprised function of the hypothalamic-pituitary-adrenal axis (1-h cortisol awakening response, evening levels, postdexamethasone levels), the immune system (basal and lipopolysaccharide-stimulated inflammation) and the autonomic nervous system (heart rate, pre-ejection period, SD of the normal-to-normal interval, respiratory sinus arrhythmia). The number of recent adverse life events was assessed at baseline using the List of Threatening Events Questionnaire. Hypothalamic-pituitary-adrenal axis, immune system and autonomic nervous system functioning was not associated with onset of chronic multisite musculoskeletal pain, either by itself or in interaction with adverse life events. Adverse life events did predict onset of chronic multisite musculoskeletal pain (HR per event=1.14, 95% CI 1.04 to 1.24, p=0.005). This longitudinal study could not confirm that dysregulated biological stress systems increase the risk of developing chronic multisite musculoskeletal pain. Adverse life events were a risk factor for the onset of chronic multisite musculoskeletal pain, suggesting that psychosocial factors play a role in triggering the development of this condition. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

METRO-APEX Volume 8.1: Water Quality Manager's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The water Quality Manager's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air…

METRO-APEX Volume 21.1: Pressure Groups' Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Pressure Groups' Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 20.1: News Media Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The News Media Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution Exercise…

METRO-APEX Volume 18.1: Legal Reference Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Legal Reference Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 10.1: Developer's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Developer's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution Exercise…

METRO-APEX Volume 4.1: County Politician's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The County Politician's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 9.1: Solid Waste Manager's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Solid Waste Manager's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 3.1: City Politician's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The City Politician's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 5.1: Planner's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Planner's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution Exercise…

METRO-APEX Volume 2.1: Computer Operator's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Computer Operator's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

METRO-APEX Volume 6.1: Environmental Quality Agency's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Environmental Quality Agency's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air…

METRO-APEX Volume 1.1: Game Overall Director's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Game Overall Director's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air…

An Analytical Model for Two-Order Asperity Degradation of Rock Joints Under Constant Normal Stiffness Conditions

NASA Astrophysics Data System (ADS)

Li, Yingchun; Wu, Wei; Li, Bo

2018-05-01

Jointed rock masses during underground excavation are commonly located under the constant normal stiffness (CNS) condition. This paper presents an analytical formulation to predict the shear behaviour of rough rock joints under the CNS condition. The dilatancy and deterioration of two-order asperities are quantified by considering the variation of normal stress. We separately consider the dilation angles of waviness and unevenness, which decrease to zero as the normal stress approaches the transitional stress. The sinusoidal function naturally yields the decay of dilation angle as a function of relative normal stress. We assume that the magnitude of transitional stress is proportionate to the square root of asperity geometric area. The comparison between the analytical prediction and experimental data shows the reliability of the analytical model. All the parameters involved in the analytical model possess explicit physical meanings and are measurable from laboratory tests. The proposed model is potentially practicable for assessing the stability of underground structures at various field scales.

The effect of inertia, viscous damping, temperature and normal stress on chaotic behaviour of the rate and state friction model

NASA Astrophysics Data System (ADS)

Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

2018-04-01

A fundamental understanding of frictional sliding at rock surfaces is of practical importance for nucleation and propagation of earthquakes and rock slope stability. We investigate numerically the effect of different physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic behaviour of the two state variables rate and state friction (2sRSF) model. In general, a slight variation in any of inertia, viscous damping, temperature and effective normal stress reduces the chaotic behaviour of the sliding system. However, the present study has shown the appearance of chaos for the specific values of normal stress before it disappears again as the normal stress varies further. It is also observed that magnitude of system stiffness at which chaotic motion occurs, is less than the corresponding value of critical stiffness determined by using the linear stability analysis. These results explain the practical observation why chaotic nucleation of an earthquake is a rare phenomenon as reported in literature.

A patient with stress-related onset and exacerbations of Graves disease.

PubMed

Vita, Roberto; Lapa, Daniela; Vita, Giuseppe; Trimarchi, Francesco; Benvenga, Salvatore

2009-01-01

An 18-year-old, nonsmoking woman presented to her general practitioner with a 1-week history of weakness, fatigue, palpitations, nervousness, tremors, insomnia, heat intolerance, and sudden enlargement of a thyroid goiter that had been detected 2 years earlier. The patient's symptoms had started shortly after she experienced emotional stress. Diagnostic work-up disclosed an avid radioactive iodine uptake by the goiter. On ultrasound examination, the thyroid gland was enlarged with a diffusely hypoechogenic structure and intense vascularization. Thyroid scintigraphy with (131)I; ultrasonography of the thyroid gland; and measurements of serum free T(3), free T(4), TSH levels and thyroid autoantibodies, including autoantibodies against thyroglobulin (TgAb), thyroperoxidase (TPOAb) and TSH receptor (TRAb). Graves disease, with stress-related onset and subsequent stress-related exacerbations. The patient was treated with methimazole to normalize levels of thyroid hormone and thyroid autoantibodies, and with bromazepam to help her cope with stress. The daily dose of methimazole was kept low during pregnancy. Over the 4 year period when the patient was taking methimazole, exacerbations of hyperthyroidism occurred twice: during her first pregnancy and 9 months after her first delivery. On all three occasions, symptoms were preceded by stressful life events. Further exacerbations were avoided by starting bromazepam treatment soon after the patient experienced stressful events.

Knockdown of an inflorescence meristem-specific cytokinin oxidase - OsCKX2 in rice reduces yield penalty under salinity stress condition.

PubMed

Joshi, Rohit; Sahoo, Khirod Kumar; Tripathi, Amit Kumar; Kumar, Ritesh; Gupta, Brijesh Kumar; Pareek, Ashwani; Singla-Pareek, Sneh Lata

2018-05-01

Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyse irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2 - in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content and photosynthetic efficiency and reduced electrolyte leakage as compared with the wild type under salinity stress. Importantly, we found a negative correlation between OsCKX2 expression and plant productivity as evident by assessment of agronomical parameters such as panicle branching, filled grains per plant and harvest index both under control and salinity stress conditions. These results suggest that OsCKX2, via controlling cytokinin levels, regulates floral primordial activity modulating rice grain yield under normal as well as abiotic stress conditions. © 2017 John Wiley & Sons Ltd.

Life stress and illness: a systems approach.

PubMed

Christie-Seely, J

1983-03-01

The link between stress and illness has been forged by researchers like Holmes and Rahe whose Social Readjustment Rating Scale can be used by family physicians to assess their patients' stress. The concept of stress has been clarified by the systems approach to illness. Stress and illness are embedded in a biopsychosocial matrix of several systems levels, each of which may be a source of stress as well as a support system. Stress is not the end result of a linear chain of causes and effects, but part of a feedback system in a community or family. The family is the major source of lifestyle and personality, the health belief system and modes of problem solving and coping, as well as of stress and support. The family physician can have a major role in educating the individual and family about stress and illness, and in altering the meaning of stress from catastrophe to challenge and source of growth. Anticipatory guidance for the normal crises of the life cycle and the crises of illness, loss and death can help prevent further family dysfunction and illness.

Apparent stress, fault maturity and seismic hazard for normal-fault earthquakes at subduction zones

USGS Publications Warehouse

Choy, G.L.; Kirby, S.H.

2004-01-01

The behavior of apparent stress for normal-fault earthquakes at subduction zones is derived by examining the apparent stress (?? a = ??Es/Mo, where E s is radiated energy and Mo is seismic moment) of all globally distributed shallow (depth, ?? 1 MPa) are also generally intraslab, but occur where the lithosphere has just begun subduction beneath the overriding plate. They usually occur in cold slabs near trenches where the direction of plate motion across the trench is oblique to the trench axis, or where there are local contortions or geometrical complexities of the plate boundary. Lower ??a (< 1 MPa) is associated with events occurring at the outer rise (OR) complex (between the OR and the trench axis), as well as with intracrustal events occurring just landward of the trench. The average apparent stress of intraslab-normal-fault earthquakes is considerably higher than the average apparent stress of interplate-thrust-fault earthquakes. In turn, the average ?? a of strike-slip earthquakes in intraoceanic environments is considerably higher than that of intraslab-normal-fault earthquakes. The variation of average ??a with focal mechanism and tectonic regime suggests that the level of ?? a is related to fault maturity. Lower stress drops are needed to rupture mature faults such as those found at plate interfaces that have been smoothed by large cumulative displacements (from hundreds to thousands of kilometres). In contrast, immature faults, such as those on which intraslab-normal-fault earthquakes generally occur, are found in cold and intact lithosphere in which total fault displacement has been much less (from hundreds of metres to a few kilometres). Also, faults on which high ??a oceanic strike-slip earthquakes occur are predominantly intraplate or at evolving ends of transforms. At subduction zones, earthquakes occurring on immature faults are likely to be more hazardous as they tend to generate higher amounts of radiated energy per unit of moment than earthquakes occurring on mature faults. We have identified earthquake pairs in which an interplate-thrust and an intraslab-normal earthquake occurred remarkably close in space and time. The intraslab-normal member of each pair radiated anomalously high amounts of energy compared to its thrust-fault counterpart. These intraslab earthquakes probably ruptured intact slab mantle and are dramatic examples in which Mc (an energy magnitude) is shown to be a far better estimate of the potential for earthquake damage than Mw. This discovery may help explain why loss of life as a result of intraslab earthquakes was greater in the 20th century in Latin America than the fatalities associated with interplate-thrust events that represented much higher total moment release. ?? 2004 RAS.

Transcriptional responses of the rat vasopressin gene to acute and repeated acute osmotic stress.

PubMed

Zemo, David A; McCabe, Joseph T

2002-09-01

To determine the impact of hypertonic saline administration upon rat arginine vasopressin (AVP) gene transcription in supraoptic nucleus neurons, a probe complementary to the first intron (AVP1) of AVP was used to measure changes in AVP heteronuclear RNA (hnRNA) levels. Animals that received hypertonic saline had increases in AVP1 after 15 and 30 min, with a return to baseline levels by 180 min. In a double injection paradigm, animals were given an injection of normal or hypertonic saline followed 180 min later by a second injection of normal or hypertonic saline and sacrificed 30 min later. When both injections were hypertonic saline (H-H), AVP1 levels were greater than levels seen after a single hypertonic saline injection, or after an injection of normal saline followed by a second injection of hypertonic saline (N-H). This study shows acute, repeated exposure to hypertonic saline causes a robust increase in vasopressin gene transcription. Since a second hyperosmotic stimulus is known to increase neuronal firing rate and activity, our results suggest that a correlation exists with intracellular mechanisms regulating vasopressin gene transcription.

Novel Monitoring Techniques for Characterizing Frictional Interfaces in the Laboratory

PubMed Central

Selvadurai, Paul A.; Glaser, Steven D.

2015-01-01

A pressure-sensitive film was used to characterize the asperity contacts along a polymethyl methacrylate (PMMA) interface in the laboratory. The film has structural health monitoring (SHM) applications for flanges and other precision fittings and train rail condition monitoring. To calibrate the film, simple spherical indentation tests were performed and validated against a finite element model (FEM) to compare normal stress profiles. Experimental measurements of the normal stress profiles were within −7.7% to 6.6% of the numerical calculations between 12 and 50 MPa asperity normal stress. The film also possessed the capability of quantifying surface roughness, an important parameter when examining wear and attrition in SHM applications. A high definition video camera supplied data for photometric analysis (i.e., the measure of visible light) of asperities along the PMMA-PMMA interface in a direct shear configuration, taking advantage of the transparent nature of the sample material. Normal stress over individual asperities, calculated with the pressure-sensitive film, was compared to the light intensity transmitted through the interface. We found that the luminous intensity transmitted through individual asperities linearly increased 0.05643 ± 0.0012 candelas for an increase of 1 MPa in normal stress between normal stresses ranging from 23 to 33 MPa. PMID:25923930

Women with previous stress fractures show reduced bone material strength

PubMed Central

Duarte Sosa, Daysi; Fink Eriksen, Erik

2016-01-01

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls. Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined. Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover. Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients. PMID:27321443

Mediating and moderating effects of work-home interference upon farm stresses and psychological distress.

PubMed

McShane, Connar Jo; Quirk, Frances

2009-10-01

This study investigated whether work-home (WHI) or home-work interference (HWI) explained or affected the strength of the relationship between farmers' stresses and reported psychological distress. Distribution of questionnaire package; included Work-Home Conflict Scale, Farm Stress Survey, Depression Anxiety Stress Scale. Participants recruited via advertising in newsletters and newspapers, and distribution through businesses and meetings. The majority of farmers (N = 51, male = 45, female = 5) were recruited from the one district. Farmers were individuals who identified their occupation as a farm owner, farm manager, or farm hand. It was predicted farmers would report higher levels of WHI than HWI; time, a determinant of interference, would mediate the relationship between farmers' stresses and psychological distress; WHI and HWI would moderate farmers' stresses and their psychological distress; overall reported level of psychological distress would be in normal to mild range because of positive general economic conditions. Farmers reported significantly higher levels of WHI than HWI (M = 3.21, M = 2.76, P < 0.001 respectively). WHI and time-based WHI mediated farmers' stresses and psychological distress, particularly anxiety. WHI, time and strain, determinants of WHI mediated personal finances and subcomponents of psychological distress (stress, anxiety, depression). Time-based HWI mediated personal finances and stress. No moderating effects were found for WHI (r = -0.02, P = 0.882) or HWI (r = 0.15, P = 0.306). Farmers of this specific sample presented a unique work-home interface. Limitations include the small sample size, recruitment methods, and culturally irrelevant measures as well as only assessing work-related stresses. Future research should aim to develop measures appropriate for farmers of Australia.

The ameliorative effect of thymol against hydrocortisone-induced hepatic oxidative stress injury in adult male rats.

PubMed

Aboelwafa, Hanaa R; Yousef, Hany N

2015-08-01

The aim of the present study was to investigate whether hydrocortisone induces oxidative stress in hepatocytes and to evaluate the possible ameliorative effect of thymol against such hepatic injury. Twenty-four adult male rats were divided into control, thymol, hydrocortisone, and hydrocortisone+thymol groups. The 4 groups were treated daily for 15 days. Hydrocortisone significantly induced oxidative stress in the liver tissues, marked by increased serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total oxidative capacity (TOC), and tumor necrosis factor-alpha (TNF-α) accompanied by marked decline of serum levels of total protein, albumin, and total antioxidant capacity (TAC). Also, marked elevation in the levels of the thiobarbituric acid reactive substances (TBARS) and TNF-α, beside significant decrease in the level of glutathione (GSH) in hepatic tissues were recorded. These biochemical alterations were accompanied by histopathological changes marked by destruction of the normal hepatic architecture, in addition to ultrastructural alterations represented by degenerative features covering almost all the cytoplasmic organelles of the hepatocytes. Supplementation of hydrocortisone-treated rats with thymol reversed most of the biochemical, histological, and ultrastructural alterations. The results of our study confirm that thymol has strong ameliorative effect against hydrocortisone-induced oxidative stress injury in hepatic tissues.

Bioactive Compounds of Kimchi Inhibit Apoptosis by Attenuating Endoplasmic Reticulum Stress in the Brain of Amyloid β-Injected Mice.

PubMed

Woo, Minji; Noh, Jeong Sook; Cho, Eun Ju; Song, Yeong Ok

2018-05-16

This study investigated the inhibitory effects of kimchi bioactive compounds against endoplasmic reticulum (ER) stress-induced apoptosis in amyloid beta (Aβ)-injected mice. Mice received a single intracerebroventricular injection of Aβ 25-35 , except for the normal group. Mice were subjected to oral administration of 10 mg of capsaicin, 50 mg of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), 50 mg of quercetin, 50 mg of ascorbic acid, or 200 mg of kimchi methanol extract (KME) per kilogram of body weight for 2 weeks ( n = 7 per group). In the in vitro blood-brain barrier (BBB) permeability test, all bioactive compounds penetrated the BBB except ascorbic acid. The protein expression level of APP, BACE, and p-Tau elevated by Aβ injection was decreased by kimchi bioactive compounds ( P < 0.05). Quercetin, HDMPPA, and KME decreased oxidative stress, as indicated by ROS and TBARS levels ( P < 0.05). The protein expression level of ER stress markers GRP78, p-PERK, p-eIF2α, XBP1, and CHOP and the proapoptotic molecules Bax, p-JNK, and cleaved caspases-3 and -9 decreased ( P < 0.05). In contrast, the protein expression level of antiapoptotic molecules Bcl2 and cIAP increased ( P < 0.05). These results were supported by histological analysis.

FITNESS, a CCT domain-containing protein, deregulates reactive oxygen species levels and leads to fine-tuning trade-offs between reproductive success and defense responses in Arabidopsis.

PubMed

Osella, Ana Virginia; Mengarelli, Diego Alberto; Mateos, Julieta; Dong, Shuchao; Yanovsky, Marcelo J; Balazadeh, Salma; Valle, Estela Marta; Zanor, María Inés

2018-05-31

Environmental stresses are the major factors that limit productivity in plants. Here, we report on the function of an uncharacterized gene At1g07050, encoding a CCT domain-containing protein, from Arabidopsis thaliana. At1g07050 expression is highly repressed by oxidative stress. We used metabolomics, biochemical and genomic approaches to analyze performance of transgenic lines with altered expression of At1g07050 under normal and oxidative stress conditions. At1g07050 overexpressing lines showed increased levels of reactive oxygen species (ROS) while knock-out mutants exhibited decreased levels of ROS and higher tolerance to oxidative stress generated in the chloroplast. Our results uncover a role for At1g07050 in cellular redox homeostasis controlling H 2 O 2 levels, due to changes in enzymes, metabolites and transcripts related to ROS detoxification. Therefore, we call this gene FITNESS. Additionally, several genes such as ACD6, PCC1, and ICS1 related to SA signalling and defense were found differentially expressed among the lines. Notably, FITNESS absence significantly improved seed yield suggesting an effective fine-tuning trade-off between reproductive success and defense responses. This article is protected by copyright. All rights reserved.

Stress and the Hair Growth Cycle: Cortisol-Induced Hair Growth Disruption.

PubMed

Thom, Erling

2016-08-01

The stress hormone, cortisol, is known to affect the function and cyclic regulation of the hair follicle. When cortisol is present at high levels it has been demonstrated to reduce the synthesis and accelerate the degradation of important skin elements, namely hyaluronan and proteoglycans by approximately 40%. The following discussion outlines the relationship between stress, cortisol, and the effect on the normal function of the hair follicle. As a result of this connection, important correlations have been established in the literature to form a basis for novel, effective treatments of stress-related hair growth disorders.
Amongst various treatment methods and substances, oral supplementation with a specific bioavailable proteoglycan stands out as a promising new therapeutic treatment method.

J Drugs Dermatol. 2016;15(8):1001-1004.

Physiological and biochemical responses of Prorocentrum minimum to high light stress

NASA Astrophysics Data System (ADS)

Park, So Yun; Choi, Eun Seok; Hwang, Jinik; Kim, Donggiun; Ryu, Tae Kwon; Lee, Taek-Kyun

2009-12-01

Prorocentrum minimum is a common bloomforming photosynthetic dinoflagellate found along the southern coast of Korea. To investigate the adaptive responses of P. minimum to high light stress, we measured growth rate, and generation of reactive oxidative species (ROS), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in cultures exposed to normal (NL) and high light levels (HL). The results showed that HL (800 μmol m-2 s-1) inhibited growth of P. minimum, with maximal inhibition after 7-9 days. HL also increased the amount of ROS and MDA, suggesting that HL stress leads to oxidative damage and lipid peroxidation in this species. Under HL, we first detected superoxide on day 4 and H2O2 on day 5. We also detected SOD activity on day 5 and CAT activity on day 6. The level of lipid peroxidation, an indicator of cell death, was high on day 8. Addition of diphenyleneiodonium (DPI), an NAD(P)H inhibitor, decreased the levels of superoxide generation and lipid peroxidation. Our results indicate that the production of ROS which results from HL stress in P. minimum also induces antioxidative enzymes that counteract oxidative damage and allow P. minimum to survive.

Urinary excretion values in 2-day food-deprived, unrestrained chimpanzees.

NASA Technical Reports Server (NTRS)

Mcnew, J. J.; Sabbot, I. M.; Hoshizaki, T.; Mandell, A. J.; Spooner, C. E.; Marcus, I.; Adey, W. R.

1972-01-01

A study was conducted to determine the baseline 24-hr urinary excretion values in the young, unrestrained chimpanzee, and also changes in urinary values, if any, induced by the two-day food deprivation stress. Urine was analyzed for volume, osmolarity, creatinine, creatine, urea nitrogen, 17-hydroxycorticosteroids (17-OHCS), 3-methoxy-4-hydroxymandelic acid (VMA), calcium, and inorganic phosphorus. Significant increases due to food deprivation stress were observed for volume, creatine, urea nitrogen, 17-OHCS, VMA, and phosphorus values, with significant decreases in osmolarity and calcium. All values approached normal levels by the second poststress day. No significant changes were observed in creatinine. A comparison is drawn between human and chimpanzee adaptation to stress.

Regulation of ethanol intake under chronic mild stress: roles of dopamine receptors and transporters.

PubMed

Delis, Foteini; Rombola, Christina; Bellezza, Robert; Rosko, Lauren; Grandy, David K; Volkow, Nora D; Thanos, Panayotis K

2015-01-01

Studies have shown that exposure to chronic mild stress decreases ethanol intake and preference in dopamine D2 receptor wild-type mice (Drd2 (+/+)), while it increases intake in heterozygous (Drd2 (+/-)) and knockout (Drd2 (-/-)) mice. Dopaminergic neurotransmission in the basal forebrain plays a major role in the reinforcing actions of ethanol as well as in brain responses to stress. In order to identify neurochemical changes associated with the regulation of ethanol intake, we used in vitro receptor autoradiography to measure the levels and distribution of dopamine D1 and D2 receptors and dopamine transporters (DAT). Receptor levels were measured in the basal forebrain of Drd2 (+/+), Drd2 (+/-), and Drd2 (-/-) mice belonging to one of four groups: control (C), ethanol intake (E), chronic mild stress exposure (S), and ethanol intake under chronic mild stress (ES). D2 receptor levels were higher in the lateral and medial striatum of Drd2 (+/+) ES mice, compared with Drd2 (+/+) E mice. Ethanol intake in Drd2 (+/+) mice was negatively correlated with striatal D2 receptor levels. D2 receptor levels in Drd2(+/-) mice were the same among the four treatment groups. DAT levels were lower in Drd2(+/-) C and Drd2 (-/-) C mice, compared with Drd2 (+/+) C mice. Among Drd2(+/-) mice, S and ES groups had higher DAT levels compared with C and E groups in most regions examined. In Drd2(-/-) mice, ethanol intake was positively correlated with DAT levels in all regions studied. D1 receptor levels were lower in Drd2(+/-) and Drd2(-/-) mice, compared with Drd2(+/+), in all regions examined and remained unaffected by all treatments. The results suggest that in normal mice, ethanol intake is associated with D2 receptor-mediated neurotransmission, which exerts a protective effect against ethanol overconsumption under stress. In mice with low Drd2 expression, where DRD2 levels are not further modulated, ethanol intake is associated with DAT function which is upregulated under stress leading to ethanol overconsumption.

Incidence of depression, anxiety and stress following traumatic injury: a longitudinal study.

PubMed

Wiseman, Taneal A; Curtis, Kate; Lam, Mary; Foster, Kim

2015-03-28

Traumatic injury and mental health disorders are co-associated. Early identification of depression, anxiety and stress following injury, and subsequent preventive intervention, may reduce the long-term symptoms and negative impacts associated with depression and anxiety. The purpose of the study was to determine the incidence, severity and predictors of depression, anxiety and stress in injured patients in the acute phase of care, and at six months following injury, as well as the effectiveness of an in-hospital screening tool. This descriptive longitudinal study of trauma patients was conducted at a Level 1 Metropolitan Trauma Centre in Australia over 14 months. Participants were interviewed using the Depression Anxiety Stress Scale short-form version (DASS-21) during hospital admission then at 3 and 6 months after injury. Descriptive statistics were performed to evaluate participant characteristics and incidence of depression, anxiety and stress. Correlations and logistic regression were conducted to investigate the ability of the DASS-21 to predict symptoms of depression, anxiety and stress and to investigate factors associated with depression, anxiety and stress 6 months after injury. 201 participants ranging in age (18-94 years) and injury severity participated in the baseline interview and 109 completed all 3 interviews over 6 months. Over half (54%) reported above normal scores for depression, anxiety and/or stress in at least one of the 3 time points. Intensive care unit admission and high levels of depression, anxiety and stress at 3 months post injury were predictors for high levels of depression, anxiety and stress at 6 months. Low scores for depression, anxiety and stress during admission were correlated with low scores for depression, anxiety and stress at 3 and 6 months. Depression, anxiety and stress in patients hospitalised following injury is common and should be anticipated in patients who have had an intensive care admission. Screening at 3 months following injury identifies patients at risk of long-term symptoms of depression, anxiety and stress.

Pectinase-treated Panax ginseng protects heat stress-induced testicular damage in rats.

PubMed

Kim, Min Kyoung; Cha, Kyu-Min; Hwang, Seock-Yeon; Park, Un-Kyu; Seo, Seok Kyo; Lee, Sang-Ho; Jeong, Min-Sik; Cho, SiHyun; Kopalli, Spandana Rajendra; Kim, Si-Kwan

2017-06-01

Testicular hyperthermia is well studied to cause impaired spermatogenesis. In the present study, the protective effect of enzymatically modified (pectinase-treated) Panax ginseng (GINST) against intermittent sub-chronic heat stress-induced testicular damage in rats was investigated. Male Sprague-Dawley rats were divided into four groups: normal control (NC), heat-stressed control (HC), heat-stressed plus GINST-100 mg/kg/day (HG100) and heat-stressed plus GINST-200 mg/kg/day (HG200) treatment groups. GINST (100 and 200 mg/kg/day) was mixed separately with a regular pellet diet and was administered orally for 8 weeks starting from 1 week before heat exposure. Parameters such as organ weight, blood chemistry, sperm kinetic values, expression of antioxidant enzymes, spermatogenesis molecules and sex hormone receptors levels were measured. Data revealed that kidney and epididymis weight were significantly ( P  < 0.05) decreased with heat stress and recovered by GINST treatment. Further, the altered levels of blood chemistry panels and sperm kinetic values in heat stress-induced rats were attenuated when GINST was administered ( P  < 0.05). Furthermore, the expression levels of antioxidant-related enzymes (GSTM5 and GPX4), spermatogenesis-related proteins (CREB1 and INHA) and sex hormone receptors (androgen receptor, luteinizing hormone receptor and follicle-stimulating hormone receptor) were reduced by heat stress; however, GINST treatment effectively ameliorated these changes. In conclusion, GINST was effective in reducing heat-induced damage in various male fertility factors in vivo and has considerable potential to be developed as a useful supplement in improving male fertility. © 2017 Society for Reproduction and Fertility.

Effects of Music Therapy on the Cardiovascular and Autonomic Nervous System in Stress-Induced University Students: A Randomized Controlled Trial.

PubMed

Lee, Kyoung Soon; Jeong, Hyeon Cheol; Yim, Jong Eun; Jeon, Mi Yang

2016-01-01

Stress is caused when a particular relationship between the individual and the environment emerges. Specifically, stress occurs when an individual's abilities are challenged or when one's well-being is threatened by excessive environmental demands. The aim of this study was to measure the effects of music therapy on stress in university students. Randomized controlled trial. Sixty-four students were randomly assigned to the experimental group (n = 33) or the control group (n = 31). Music therapy. Initial measurement included cardiovascular indicators (blood pressure and pulse), autonomic nervous activity (standard deviation of the normal-to-normal intervals [SDNN], normalized low frequency, normalized high frequency, low/high frequency), and subjective stress. After the first measurement, participants in both groups were exposed to a series of stressful tasks, and then a second measurement was conducted. The experimental group then listened to music for 20 minutes and the control group rested for 20 minutes. A third and final measurement was then taken. There were no significant differences between the two groups in the first or second measurement. However, after music therapy, the experimental group and the control group showed significant differences in all variables, including systolic blood pressure (p = .026), diastolic blood pressure (p = .037), pulse (p < .001), SDNN (p = .003), normalized low frequency (p < .001), normalized high frequency (p = .010), and subjective stress (p = .026). Classical music tends to relax the body and may stimulate the parasympathetic nervous system. These results suggest music therapy as an intervention for stress reduction.

Maternal stress modifies the effect of exposure to lead during pregnancy and 24-month old children's neurodevelopment.

PubMed

Tamayo Y Ortiz, Marcela; Téllez-Rojo, Martha María; Trejo-Valdivia, Belem; Schnaas, Lourdes; Osorio-Valencia, Erika; Coull, Brent; Bellinger, David; Wright, Rosalind J; Wright, Robert O

2017-01-01

Lead and psychosocial stress disrupt similar but not completely overlapping mechanisms. Exposure during the prenatal period to each of these insults singularly has been found to alter normal neurodevelopment; however, longitudinal associations with stress modifying the effect of lead have not been sufficiently analyzed in epidemiologic studies. To evaluate prenatal stress as an effect modifier of gestational lead neurotoxicity. We used a structural equations modeling approach with a trivariate response to evaluate cognitive, language and motor scores of the Bayley Scales of Infant Development-III in 24month-old children (n=360). Maternal blood lead levels were measured at the 2nd and 3rd trimester and psychosocial stress during pregnancy was assessed using a negative life events (NLE) scale derived from the CRYSIS questionnaire. 3rd trimester lead (mean 3.9±3.0 SDμg/dL) and stress (median=3 NLE) were negatively associated with Bayley III scores. Using the model's results we generated profiles for 0, 2, 4 and 6 NLE across lead levels (up to 10μg/dL) and observed a dose-response for the developmental scores when lead levels were below 2μg/dL. Each NLE curve had a different shape across increasing lead levels. Higher stress (NLE=6) resulted in lower cognitive scores for both sexes, in lower language scores in girls but not boys. In the absence of stress we saw a negative association with lead for all scores, however for language and motor scores, higher stress seemed to mask this association. Our work examined and confirmed prenatal stress exposure as a modifier of the well-known neurotoxic effects of prenatal lead. It adds to the existing evidence pointing at the importance of studying the co-exposure of chemical and non-chemical exposures, specifically of considering the emotional environment of children at early developmental stages of life. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maternal stress modifies the effect of exposure to lead during pregnancy and 24-month old children's neurodevelopment

PubMed Central

Ortiz, Marcela Tamayo y; Téllez-Rojo, Martha María; Trejo-Valdivia, Belem; Schnaas, Lourdes; Osorio-Valencia, Erika; Coull, Brent; Bellinger, David; Wright, Rosalind J.; Wright, Robert O.

2016-01-01

Background Lead and psychosocial stress disrupt similar but not completely overlapping mechanisms. Exposure during the prenatal period to each of these insults singularly has been found to alter normal neurodevelopment; however, longitudinal associations with stress modifying the effect of lead have not been sufficiently analyzed in epidemiologic studies. Objective To evaluate prenatal stress as an effect modifier of gestational lead neurotoxicity. Methods We used a structural equations modeling approach with a trivariate response to evaluate cognitive, language and motor scores of the Bayley Scales of Infant Development-III in 24 month-old children (n=360). Maternal blood lead levels were measured at the 2nd and 3rd trimester and psychosocial stress during pregnancy was assessed using a negative life events (NLE) scale derived from the CRYSIS questionnaire. Results 3rd trimester lead (mean 3.9 ± 3.0 SD μg/dL) and stress (median=3 NLE) were negatively associated with Bayley III scores. Using the model's results we generated profiles for 0, 2, 4 and 6 NLE across lead levels (up to 10 μg/dL) and observed a dose-response for the developmental scores when lead levels were below 2 μg/dL. Each NLE curve had a different shape across increasing lead levels. Higher stress (NLE=6) resulted in lower cognitive scores for both sexes, in lower language scores in girls but not boys. In the absence of stress we saw a negative association with lead for all scores, however for language and motor scores, higher stress seemed to mask this association. Conclusions Our work examined and confirmed prenatal stress exposure as a modifier of the well-known neurotoxic effects of prenatal lead. It adds to the existing evidence pointing at the importance of studying the co-exposure of chemical and non-chemical exposures, specifically of considering the emotional environment of children at early developmental stages of life. PMID:27865525

Effects of levetiracetam in lipid peroxidation level, nitrite-nitrate formation and antioxidant enzymatic activity in mice brain after pilocarpine-induced seizures.

PubMed

Oliveira, A A; Almeida, J P C; Freitas, R M; Nascimento, V S; Aguiar, L M V; Júnior, H V N; Fonseca, F N; Viana, G S B; Sousa, F C F; Fonteles, M M F

2007-05-01

: Oxidative stress has been implicated in a large number of human degenerative diseases, including epilepsy. Levetiracetam (LEV) is a new antiepileptic agent with broad-spectrum effects on seizures and animal models of epilepsy. Recently, it was demonstrated that the mechanism of LEV differs from that of conventional antiepileptic drugs. Objectifying to investigate if LEV mechanism of action involves antioxidant properties, lipid peroxidation levels, nitrite-nitrate formation, catalase activity, and glutathione (GSH) content were measured in adult mice brain. The neurochemical analyses were carried out in hippocampus of animals pretreated with LEV (200 mg/kg, i.p.) 60 min before pilocarpine-induced seizures (400 mg/kg, s.c.). The administration of alone pilocarpine, 400 mg/kg, s.c. (P400) produced a significant increase of lipid peroxidation level in hippocampus. LEV pretreatment was able to counteract this increase, preserving the lipid peroxidation level in normal value. P400 administration also produced increase in the nitrite-nitrate formation and catalase activity in hippocampus, beyond a decrease in GSH levels. LEV administration before P400 prevented the P400-induced alteration in nitrite-nitrate levels and preserved normal values of catalase activity in hippocampus. Moreover, LEV administration prevented the P400-induced loss of GSH in this cerebral area. The present data suggest that the protective effects of LEV against pilocarpine-induced seizures can be mediated, at least in part, by reduction of lipid peroxidation and hippocampal oxidative stress.

Parameters of hormetic stress and resilience to trauma in rats.

PubMed

Plumb, Traci N; Cullen, Patrick K; Minor, Thomas R

2015-01-01

Hormesis is the process by which small stresses build resilience to large stresses. We pre-exposed rats to various parameters of mild-to-moderate stress prior to traumatic stress in the present experiments to assess the potential benefits of hormetic training on resilience to traumatic, uncontrollable stress. Rats underwent varying stress pre-training parameters prior to exposure to uncontrollable traumatic stress in the learned helplessness procedure. The ability to prevent the exaggerated fear responding and escape deficits that normally follow experience with traumatic stress were used as a measure of the benefits of hormetic training. Four experiments examined the effects of number of training sessions, stressor severity and pattern of rest between pre-training stress sessions. Repeated exposure to mild restraint stress or moderate shock stress eliminated both the enhanced fear conditioning and shuttle-escape deficits that result from exposure to traumatic, inescapable shock. The pattern of rest did not contribute to resilience when the pre-exposure stressor was mild, but was vital when the pre-exposure stressor was moderate, with an alternation of stress and rest being the most effective procedure. The data also suggest that the level of resilience may increase with the number of pre-exposure sessions.

The influence of topographic stresses on faulting, emphasizing the 2008 Wenchuan, China earthquake rupture

NASA Astrophysics Data System (ADS)

Styron, R. H.; Hetland, E. A.; Zhang, G.

2013-12-01

The weight of large mountains produces stresses in the crust that locally may be on the order of tectonic stresses (10-100 MPa). These stresses have a significant and spatially-variable deviatoric component that may be resolved as strong normal and shear stresses on range-bounding faults. In areas of high relief, the shear stress on faults can be comparable to inferred stress drops in earthquakes, and fault-normal stresses may be greater than 50 MPa, and thus may potentially influence fault rupture. Additionally, these stresses may be used to make inferences about the orientation and magnitude of tectonic stresses, for example by indicating a minimum stress needed to be overcome by tectonic stress. We are studying these effects in several tectonic environments, such as the Longmen Shan (China), the Denali fault (Alaska, USA) and the Wasatch Fault Zone (Utah, USA). We calculate the full topographic stress tensor field in the crust in a study region by convolution of topography with Green's functions approximating stresses from a point load on the surface of an elastic halfspace, using the solution proposed by Liu and Zoback [1992]. The Green's functions are constructed from Boussinesq's solutions for a vertical point load on an elastic halfspace, as well as Cerruti's solutions for a horizontal surface point load, accounting for irregular surface boundary and topographic spreading forces. The stress tensor field is then projected onto points embedded in the halfspace representing the faults, and the fault normal and shear stresses at each point are calculated. Our primary focus has been on the 2008 Wenchuan earthquake, as this event occurred at the base of one of Earth's highest and steepest topographic fronts and had a complex and well-studied coseismic slip distribution, making it an ideal case study to evaluate topographic influence on faulting. We calculate the topographic stresses on the Beichuan and Pengguan faults, and compare the results to the coseismic slip distribution, considering several published fault models. These models differ primarily in slip magnitude and planar vs. listric fault geometry at depth. Preliminary results indicate that topographic stresses are generally resistive to tectonic deformation, especially above ~10 km depth, where the faults are steep in all models. Down-dip topographic shear stresses on the fault are normal sense where the faults dip steeply, and reach 20 MPa on the fault beneath the Pengguan massif. Reverse-sense shear up to ~15 MPa is present on gently-dipping thrust flats at depth on listric fault models. Strike-slip shear stresses are sinistral on the steep, upper portions of faults but may be dextral on thrust flats. Topographic normal stress on the faults reaches ~80 MPa on thrust ramps and may be higher on flats. Coseismic slip magnitude is negatively correlated with topographic normal and down-dip shear stresses. The spatial patterns of topographic stresses and slip suggest that topographic stresses have significantly suppressed slip in certain areas: slip maxima occur in areas of locally lower topographic stresses, while areas of higher down-dip shear and normal stress show less slip than adjacent regions.

Involvement of cortisol and sirtuin1 during the response to stress of hypothalamic circadian system and food intake-related peptides in rainbow trout, Oncorhynchus mykiss.

PubMed

Naderi, Fatemeh; Hernández-Pérez, Juan; Chivite, Mauro; Soengas, José L; Míguez, Jesús M; López-Patiño, Marcos A

2018-05-08

Stress is conditioning animal welfare by negatively affecting a wide range of physiological and behavioral functions. This may be applied to circadian physiology and food intake. Cortisol, the stress-related hormone, may mediate such effect of stress, but other indirect mediators might be considered, such as sirtuin1. Then, either the independent modulatory effect or the existence of any interaction between mediators may be responsible. The circadian system is the main modulator of several integrative mechanisms at both central and peripheral levels that are rhythmically presented, thus influencing different processes such as food intake. In this way, food intake is controlled by the circadian system, as demonstrated by the persistence of such rhythms of food intake in the absence of environmental external cues. Our study aimed to evaluate the daily profile of hypothalamic mRNA abundance of circadian clock genes (clock1a, bmal1, per1 and rev-erbβ-like), and food intake regulators (crf, pomc-a1, cart, and npy) in rainbow trout (Oncorhynchus mykiss), the impact of stress on such rhythms, and the involvement of cortisol and sirtuin1 as mediators. Four cohorts of trout were subjected to 1) normal stocking density (control group), 2) high stocking density for 72 hours (stress group), 3) normal stocking density and implanted with mifepristone, a glucocorticoid receptors antagonist, and 4) mifepristone administered and stressed for 72 hours. Fish from each group were sampled every 4-h along the 24-h LD cycle, and cortisol, glucose and lactate plasma levels were evaluated. Hypothalamic mRNA abundance of clock genes, food intake regulators, glucocorticoid receptors and sirtuin1 were qPCR assayed. Our results reveal the impact of stress on most of the genes assayed, but different mechanisms appear to be involved. The rhythm of clock genes displayed decreased amplitude and averaged levels in stressed trout, with no changes of the acrophase being observed. This effect was not prevented by mifepristone. On the contrary, the effect of stress on the daily profile of crf, pomc-a1, and npy was totally prevented by mifepristone administration. Accordingly, cortisol appears to mainly mediate the effect of stress on food intake regulators through binding to specific glucocorticoid receptors within trout hypothalamus, whereas sirtuin1 is apparently mediating such effects on the circadian system in the same brain region. Further research must be performed to clarify those mechanisms through which stress influences food intake and the circadian oscillator within the same brain region, hypothalamus, in rainbow trout, and the interaction among them all.

Molt-associated changes in hematologic and plasma biochemical values and stress hormone levels in African penguins (Spheniscus demersus).

PubMed

Mazzaro, Lisa M; Meegan, Jenny; Sarran, Delphine; Romano, Tracy A; Bonato, Vinicius; Deng, Shibing; Dunn, J Lawrence

2013-12-01

Handling, including blood collection, has often been discouraged in molting penguins because it is considered an additional stress imposed on birds already experiencing major physiologic stress associated with molting. To evaluate the degree of physiologic stress posed by molting, we compared the hematologic and plasma biochemical values and hormone levels of molting and nonmolting African penguins, Spheniscus demersus. Five male and 5 female penguins randomly chosen were given complete physical examinations, were weighed, and blood samples were taken at 7 time points before, during, and after the molt. Data were analyzed by linear mixed-model analysis of variance. Throughout the study, behavior and appetite remained normal. Catecholamine levels were highly variable within and among subjects, whereas mean corticosterone levels were significantly different between baseline, molt, and postmolt values. Significant differences from baseline values were observed in many of the hematologic analytes; however, only decreases in hematocrit and red blood cell count values were considered clinically significant. Anemia due to experimentally induced blood loss as a possible cause of the significant hematologic changes was ruled out based on results of a follow-up control study during the nonmolt season, which showed no significant changes in hematocrit level or total red blood cell counts when using similar sampling protocols, which indicates that these changes were associated with molt.

Hypoglycemic activity of Gymnema sylvestre extracts on oxidative stress and antioxidant status in diabetic rats.

PubMed

Kang, Myung-Hwa; Lee, Min Sun; Choi, Mi-Kyeong; Min, Kwan-Sik; Shibamoto, Takayuki

2012-03-14

Diabetes mellitus, which is associated with oxidative damage, has a significant impact on health, quality of life, and life expectancy. An ethanol extract of Gymnema sylvestre leaf was examined in vitro and in vivo to investigate the role of antioxidants in diabetic rats. The extract exhibited strong antioxidant activity in the assays, including TBA (56%), SOD-like (92%), and ABTS (54%). Blood glucose levels in the diabetic rats fed G. sylvestre extract decreased to normal levels. The presence of the antihyperglycemic compounds gymnemagenin and gymnemic acids in G. sylvestre extract was detected by LC/MS analysis. Lipid peroxidation levels were decreased by 31.7% in serum, 9.9% in liver, and 9.1% in kidney in the diabetic rats fed the extract. Feeding G. sylvestre extract to the diabetic rats decreased the activity of glutathione peroxidase in cytosolic liver and glutamate pyruvate transaminase in serum to normal levels.

Viscous pressure correction in the irrotational flow outside Prandtl's boundary layer

NASA Astrophysics Data System (ADS)

Joseph, Daniel; Wang, Jing

2004-11-01

We argue that boundary layers on solid with irrotational motion outside are like a gas bubble because the shear stress vanishes at the edge of the boundary layer but the irrotational shear stress does not. This discrepancy induces a pressure correction and an additional drag which can be advertised as due to the viscous dissipation of the irrotational flow. Typically, this extra correction to the drag would be relatively small. A much more interesting implication of the extra pressure theory arises from the consideration of the effects of viscosity on the normal stress on a solid boundary which are entirely neglected in Prandtl's theory. It is very well known and easily demonstrated that as a consequence of the continuity equation the viscous normal stress must vanish on a rigid solid. It follows that all the greatly important effects of viscosity on the normal stress are buried in the pressure and the leading order effects of viscosity on the normal stress can be obtained from the viscous correction of viscous potential flow.

Stress transfer mechanisms at the submicron level for graphene/polymer systems.

PubMed

Anagnostopoulos, George; Androulidakis, Charalampos; Koukaras, Emmanuel N; Tsoukleri, Georgia; Polyzos, Ioannis; Parthenios, John; Papagelis, Konstantinos; Galiotis, Costas

2015-02-25

The stress transfer mechanism from a polymer substrate to a nanoinclusion, such as a graphene flake, is of extreme interest for the production of effective nanocomposites. Previous work conducted mainly at the micron scale has shown that the intrinsic mechanism of stress transfer is shear at the interface. However, since the interfacial shear takes its maximum value at the very edge of the nanoinclusion it is of extreme interest to assess the effect of edge integrity upon axial stress transfer at the submicron scale. Here, we conduct a detailed Raman line mapping near the edges of a monolayer graphene flake that is simply supported onto an epoxy-based photoresist (SU8)/poly(methyl methacrylate) matrix at steps as small as 100 nm. We show for the first time that the distribution of axial strain (stress) along the flake deviates somewhat from the classical shear-lag prediction for a region of ∼ 2 μm from the edge. This behavior is mainly attributed to the presence of residual stresses, unintentional doping, and/or edge effects (deviation from the equilibrium values of bond lengths and angles, as well as different edge chiralities). By considering a simple balance of shear-to-normal stresses at the interface we are able to directly convert the strain (stress) gradient to values of interfacial shear stress for all the applied tensile levels without assuming classical shear-lag behavior. For large flakes a maximum value of interfacial shear stress of 0.4 MPa is obtained prior to flake slipping.

The quality of fetal arm movements as indicators of fetal stress.

PubMed

Reissland, Nadja; Francis, Brian

2010-12-01

Although a number of studies have found that maternal stress affects the fetus, it is unclear whether jerky fetal movements observed on ultrasound scans are indicative of fetal stress, or whether they are part of normal development. The present study was designed to examine the relationship between jerky fetal arm movements in relation to fetal age and stress. Video recordings were made of routine ultrasound scans of 57 fetuses (age range 8 to 33 weeks) classified into three age groups: 1st trimester (8-12 weeks, N=9), 2nd trimester (13-24 weeks, N=38), and 3rd trimester (26-33 weeks, N=10). Following previous research on stress behaviour in neonates, a fetal index of stress was derived from frequency of hiccup, back arch and rhythmical mouthing. Results indicated that while stress level was unrelated to fetal age, jerkiness of arm movements was significantly associated with the fetal stress index but not age. Our findings suggest that jerky arm movements in fetuses are suggestive of fetal stress. Copyright © 2010 Elsevier Ltd. All rights reserved.

GILZ overexpression attenuates endoplasmic reticulum stress-mediated cell death via the activation of mitochondrial oxidative phosphorylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

André, Fanny; Corazao-Rozas, Paola; Idziorek, Thierry

The Glucocorticoïd-induced leucine zipper (GILZ) protein has profound anti-inflammatory activities in haematopoietic cells. GILZ regulates numerous signal transduction pathways involved in proliferation and survival of normal and neoplastic cells. Here, we have demonstrated the potential of GILZ in alleviating apoptosis induced by ER stress inducers. Whereas the glucocorticoid, dexamethasone, protects from tunicamycin-induced cell death, silencing endogeneous GILZ in dexamethasone-treated cancer cells alter the capacity of glucocorticoids to protect from tunicamycin-mediated apoptosis. Under ER stress conditions, overexpression of GILZ significantly reduced activation of mitochondrial pathway of apoptosis by maintaining Bcl-xl level. GILZ protein affects the UPR signaling shifting the balance towardsmore » pro-survival signals as judged by down-regulation of CHOP, ATF4, XBP1s mRNA and increase in GRP78 protein level. Interestingly, GILZ sustains high mitochondrial OXPHOS during ER stress and cytoprotection mediated by GILZ is abolished in cells depleted of mitochondrial DNA, which are OXPHOS-deficient. These findings reveal a new role of GILZ, which acts as a cytoprotector against ER stress through a pathway involving mitochondrial OXPHOS. - Highlights: • GILZ attenuates apoptotic cell death induced by ER stress conditions. • GILZ promotes pro-survival signaling of the UPR. • GILZ overexpression sustains high mitochondrial activity under ER stress. • Mitochondrial OXPHOX is required for GILZ protective effects against ER stress-mediated apoptosis.« less

The role of transcriptome resilience in resistance of corals to bleaching.

PubMed

Seneca, Francois O; Palumbi, Stephen R

2015-04-01

Wild populations increasingly experience extreme conditions as climate change amplifies environmental variability. How individuals respond to environmental extremes determines the impact of climate change overall. The variability of response from individual to individual can represent the opportunity for natural selection to occur as a result of extreme conditions. Here, we experimentally replicated the natural exposure to extreme temperatures of the reef lagoon at Ofu Island (American Samoa), where corals can experience severe heat stress during midday low tide. We investigated the bleaching and transcriptome response of 20 Acropora hyacinthus colonies 5 and 20 h after exposure to control (29 °C) or heated (35 °C) conditions. We found a highly dynamic transcriptome response: 27% of the coral transcriptome was significantly regulated 1 h postheat exposure. Yet 15 h later, when heat-induced coral bleaching became apparent, only 12% of the transcriptome was differentially regulated. A large proportion of responsive genes at the first time point returned to control levels, others remained differentially expressed over time, while an entirely different subset of genes was successively regulated at the second time point. However, a noteworthy variability in gene expression was observed among individual coral colonies. Among the genes of which expression lingered over time, fast return to normal levels was associated with low bleaching. Colonies that maintained higher expression levels of these genes bleached severely. Return to normal levels of gene expression after stress has been termed transcriptome resilience, and in the case of some specific genes may signal the physiological health and response ability of individuals to environmental stress. © 2015 John Wiley & Sons Ltd.

Time courses of changes of para-, meta-, and ortho-tyrosine in septic patients: A pilot study.

PubMed

Szélig, Lívia; Kun, Szilárd; Woth, Gábor; Molnár, Gergő A; Zrínyi, Zita; Kátai, Emese; Lantos, János; Wittmann, István; Bogár, Lajos; Miseta, Attila; Csontos, Csaba

2016-07-01

Sepsis is associated with oxidative stress. Due to oxidative stress, three tyrosine isoforms, para-, meta-, and ortho-tyrosine (p-, m-, and o-Tyr), can be formed non-enzymatically in smaller amounts. p-Tyr is mainly formed physiologically in the kidneys through the activity of the phenylalanine hydroxylase enzyme. The three tyrosine isoforms may undergo different renal handling. Twenty septic patients were involved in the study and 25 healthy individuals served as controls. Blood and urine levels of p-, m-, and o-Tyr were measured on admission and four consecutive days. Serum m-Tyr levels were higher in septic patients than in controls on days 2 (P = 0.031) and 3 (P = 0.035). Serum p-Tyr levels were lower in the cases than in controls on days 1 (P = 0.005) and 2 (P = 0.040), and subsequently normalized due to a day-by-day elevation (P = 0.002). The tendency of urinary m-Tyr concentration was decreasing (P = 0.041), while that of urinary p-Tyr concentration was increasing (P = 0.001). Fractional excretion of m-Tyr (FEm-Tyr) showed a decreasing tendency (P = 0.009), and was, on all days, higher than FEp-Tyr, which remained near-normal, less than 4%. Procalcitonin showed significant correlation with FEm-Tyr (r = 0.454; P < 0.001). Our data suggest that the oxidative stress marker m-Tyr and physiologic p-Tyr may be handled differently in septic patients. The excretion of m-Tyr correlates with inflammation. m-Tyr may be actively secreted or produced in the kidney in some patients, whereas the decreased serum level of p-Tyr is a consequence of diminished renal production and not of renal loss.

Effects of levothyroxine on learning and memory deficits in a rat model of Alzheimer's disease: the role of BDNF and oxidative stress.

PubMed

Bavarsad, Kowsar; Hadjzadeh, Mousa-Al-Reza; Hosseini, Mahmoud; Pakdel, Roghayeh; Beheshti, Farimah; Bafadam, Soleyman; Ashaari, Zeinab

2018-06-21

The effect of levothyroxine (L-T4) on the learning and memory impairment induced by streptozotocin (STZ) and brain tissue oxidative damage in rats was evaluated. An animal model of the Alzheimer's disease (AD) was established by intracerebroventricular injection of STZ (3 mg/kg) in male Wistar rats (250 ± 50 g). After that, the rats were treated for 3 weeks with L-T4 (10, 100 μg/kg) or normal saline. Passive avoidance (PA) learning and spatial memory were evaluated using shuttle box and Morris water maze (MWM), respectively. Finally, the rats were euthanized, their blood samples were collected for further thyroxine assessment and their brains were removed after decapitation in order to measure the oxidative stress parameters and brain-derived neurotrophic factor (BDNF). In the MWM, latency (s) increased in the AD rats compared with the normal control group while it decreased in the 10 μg/kg L-T4 injected AD rats compared with the AD group. In the PA, the latency for entering the dark compartment was lower in the AD group than in the normal control group and it decreased in the 10 μg/kg L-T4 injected AD rats. The low dose of L-T4 (10 μg/kg) reduced malondialdehyde concentration but increased thiols concentration, superoxide dismutase, catalase activities and BDNF level in hippocampal tissues of the AD rats. Injection of L-T4 (10 μg/kg) alleviated memory deficits and also improved factors of oxidative stress and BDNF level in the STZ-induced AD rats.

Salicylic acid alleviates decreases in photosynthesis under heat stress and accelerates recovery in grapevine leaves.

PubMed

Wang, Li-Jun; Fan, Ling; Loescher, Wayne; Duan, Wei; Liu, Guo-Jie; Cheng, Jian-Shan; Luo, Hai-Bo; Li, Shao-Hua

2010-02-23

Although the effect of salicylic acid (SA) on photosynthesis of plants including grapevines has been investigated, very little is yet known about the effects of SA on carbon assimilation and several components of PSII electron transport (donor side, reaction center and acceptor side). In this study, the impact of SA pretreatment on photosynthesis was evaluated in the leaves of young grapevines before heat stress (25 degrees C), during heat stress (43 degrees C for 5 h), and through the following recovery period (25 degrees C). Photosynthetic measures included gas exchange parameters, PSII electron transport, energy dissipation, and Rubisco activation state. The levels of heat shock proteins (HSPs) in the chloroplast were also investigated. SA did not significantly (P < 0.05) influence the net photosynthesis rate (Pn) of leaves before heat stress. But, SA did alleviate declines in Pn and Rubisco activation state, and did not alter negative changes in PSII parameters (donor side, acceptor side and reaction center QA) under heat stress. Following heat treatment, the recovery of Pn in SA-treated leaves was accelerated compared with the control (H2O-treated) leaves, and, donor and acceptor parameters of PSII in SA-treated leaves recovered to normal levels more rapidly than in the controls. Rubisco, however, was not significantly (P < 0.05) influenced by SA. Before heat stress, SA did not affect level of HSP 21, but the HSP21 immune signal increased in both SA-treated and control leaves during heat stress. During the recovery period, HSP21 levels remained high through the end of the experiment in the SA-treated leaves, but decreased in controls. SA pretreatment alleviated the heat stress induced decrease in Pn mainly through maintaining higher Rubisco activation state, and it accelerated the recovery of Pn mainly through effects on PSII function. These effects of SA may be related in part to enhanced levels of HSP21.

The traditional drug Gongjin-Dan ameliorates chronic fatigue in a forced-stress mouse exercise model.

PubMed

Hong, Sung-Shin; Lee, Ji-Young; Lee, Jin-Seok; Lee, Hye-Won; Kim, Hyeong-Geug; Lee, Sam-Keun; Park, Bong-Ki; Son, Chang-Gue

2015-06-20

Gongjin-Dan is a representative traditional Oriental medicine herbal drug that has been used to treat chronic fatigue symptoms for several hundred years. We evaluated the anti-fatigue effects of Gongjin-Dan and the underlying mechanisms in a chronic forced exercise mouse model. Balb/C male mice underwent an extreme treadmill-based running stress (1-h, 5 days/week), and daily oral administration of distilled water, Gongjin-Dan (100, 200, or 400 mg/kg), or ascorbic acid (100 mg/kg) for 28 days. The anti-fatigue effects of Gongjin-Dan were evaluated with behavioral tests (exercise tolerance and swimming tests), and the corresponding mechanisms were investigated based on oxidative stress and inflammatory cytokine and stress hormone levels in skeletal muscle, sera, and brain tissue. Gongjin-Dan significantly increased exercise tolerance and latency times but reduced the number of electric shocks and immobilization time on the treadmill running and swimming tests, compared with the control group. Gongjin-Dan also significantly ameliorated alterations in oxidative stress-related biomarkers (reactive oxygen species and malondialdehyde), inflammatory cytokines (tumor necrosis factor-α, interleukin-1 beta, interleukin-6, and interferon-γ) and glycogen and L-lactate levels in skeletal muscle, compared with those in the control group. Moreover, Gongjin-Dan considerably normalized the forced running stress-induced changes in serum corticosterone and adrenaline levels, as well as brain serotonin level. These antioxidant and anti-stress effects of Gongjin-Dan were supported by the results of Western blotting (4-hydroxynonenal and heme oxygenase-1) and the gene expression levels (serotonin receptor and serotonin transporter). These results support the clinical relevance of Gongjin-Dan regarding anti-chronic fatigue properties. The underlying mechanisms involve attenuation of oxidative and inflammatory reactions in muscle and regulation of the stress response through the hypothalmo-pituitary-adrenal axis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Identification and Expression Analysis of Cytokinin Metabolic Genes in Soybean under Normal and Drought Conditions in Relation to Cytokinin Levels

PubMed Central

Le, Dung Tien; Nishiyama, Rie; Watanabe, Yasuko; Vankova, Radomira; Tanaka, Maho; Seki, Motoaki; Ham, Le Huy; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

2012-01-01

Cytokinins (CKs) mediate cellular responses to drought stress and targeted control of CK metabolism can be used to develop drought-tolerant plants. Aiming to manipulate CK levels to improve drought tolerance of soybean cultivars through genetic engineering of CK metabolic genes, we surveyed the soybean genome and identified 14 CK biosynthetic (isopentenyltransferase, GmIPT) and 17 CK degradative (CK dehydrogenase, GmCKX) genes. Comparative analyses of GmIPTs and GmCKXs with Arabidopsis counterparts revealed their similar architecture. The average numbers of abiotic stress-inducible cis-elements per promoter were 0.4 and 1.2 for GmIPT and GmCKX genes, respectively, suggesting that upregulation of GmCKXs, thereby reduction of CK levels, maybe the major events under abiotic stresses. Indeed, the expression of 12 GmCKX genes was upregulated by dehydration in R2 roots. Overall, the expressions of soybean CK metabolic genes in various tissues at various stages were highly responsive to drought. CK contents in various organs at the reproductive (R2) stage were also determined under well-watered and drought stress conditions. Although tRNA-type GmIPT genes were highly expressed in soybean, cis-zeatin and its derivatives were found at low concentrations. Moreover, reduction of total CK content in R2 leaves under drought was attributable to the decrease in dihydrozeatin levels, suggesting a role of this molecule in regulating soybean's responses to drought stress. Our systematic analysis of the GmIPT and GmCKX families has provided an insight into CK metabolism in soybean under drought stress and a solid foundation for in-depth characterization and future development of improved drought-tolerant soybean cultivars by manipulation of CK levels via biotechnological approach. PMID:22900018

Predictive value of myocardial perfusion single-photon emission computed tomography and the impact of renal function on cardiac death.

PubMed

Hakeem, Abdul; Bhatti, Sabha; Dillie, Kathryn Sullivan; Cook, Jeffrey R; Samad, Zainab; Roth-Cline, Michelle D; Chang, Su Min

2008-12-09

Patients with chronic kidney disease (CKD) have worse cardiovascular outcomes than those without CKD. The prognostic utility of myocardial perfusion single-photon emission CT (MPS) in patients with varying degrees of renal dysfunction and the impact of CKD on cardiac death prediction in patients undergoing MPS have not been investigated. We followed up 1652 consecutive patients who underwent stress MPS (32% exercise, 95% gated) for cardiac death for a mean of 2.15+/-0.8 years. MPS defects were defined with a summed stress score (normal summed stress score <4, abnormal summed stress score>or=4). Ischemia was defined as a summed stress score >or=4 plus a summed difference score >or=2, and scar was defined as a summed difference score <2 plus a summed stress score >or=4. Renal function was calculated with the Modified Diet in Renal Disease equation. CKD (estimated glomerular filtration rate <60 mL . min(-1) . 1.73 m(-2)) was present in 36%. Cardiac death increased with worsening levels of perfusion defects across the entire spectrum of renal function. Presence of ischemia was independently predictive of cardiac death, all-cause mortality, and nonfatal myocardial infarction. Patients with normal MPS and CKD had higher unadjusted cardiac death event rates than those with no CKD and normal MPS (2.7% versus 0.8%, P=0.001). Multivariate Cox proportional hazards models revealed that both perfusion defects (hazard ratio 1.90, 95% CI 1.47 to 2.46) and CKD (hazard ratio 1.96, 95% CI 1.29 to 2.95) were independent predictors of cardiac death after accounting for risk factors, left ventricular dysfunction, pharmacological stress, and symptom status. Both MPS and CKD had incremental power for cardiac death prediction over baseline risk factors and left ventricular dysfunction (global chi(2) 207.5 versus 169.3, P<0.0001). MPS provides effective risk stratification across the entire spectrum of renal function. Renal dysfunction is also an important independent predictor of cardiac death in patients undergoing MPS. Renal function and MPS have additive value in risk stratisfying patients with suspected coronary artery disease. Patients with CKD appear to have a relatively less benign prognosis than those without CKD, even in the presence of a normal scan.

Magnetic field effects on shear and normal stresses in magnetorheological finishing.

PubMed

Lambropoulos, John C; Miao, Chunlin; Jacobs, Stephen D

2010-09-13

We use a recent experimental technique to measure in situ shear and normal stresses during magnetorheological finishing (MRF) of a borosilicate glass over a range of magnetic fields. At low fields shear stresses increase with magnetic field, but become field-independent at higher magnetic fields. Micromechanical models of formation of magnetic particle chains suggest a complex behavior of magnetorheological (MR) fluids that combines fluid- and solid-like responses. We discuss the hypothesis that, at higher fields, slip occurs between magnetic particle chains and the immersed glass part, while the normal stress is governed by the MRF ribbon elasticity.

YiXin-Shu, a ShengMai-San-based traditional Chinese medicine formula, attenuates myocardial ischemia/reperfusion injury by suppressing mitochondrial mediated apoptosis and upregulating liver-X-receptor α.

PubMed

Zhao, Yichao; Xu, Longwei; Qiao, Zhiqing; Gao, Lingchen; Ding, Song; Ying, Xiaoying; Su, Yuanyuan; Lin, Nan; He, Ben; Pu, Jun

2016-03-11

Positive evidence from clinical trials has fueled growing acceptance of traditional Chinese medicine (TCM) for the treatment of cardiac diseases; however, little is known about the underlying mechanisms. Here, we investigated the nature and underlying mechanisms of the effects of YiXin-Shu (YXS), an antioxidant-enriched TCM formula, on myocardial ischemia/reperfusion (MI/R) injury. YXS pretreatment significantly reduced infarct size and improved viable myocardium metabolism and cardiac function in hypercholesterolemic mice. Mechanistically, YXS attenuated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway (as reflected by inhibition of mitochondrial swelling, cytochrome c release and caspase-9 activity, and normalization of Bcl-2 and Bax levels) without altering the death receptor and endoplasmic reticulum-stress death pathways. Moreover, YXS reduced oxidative/nitrative stress (as reflected by decreased superoxide and nitrotyrosine content and normalized pro- and anti-oxidant enzyme levels). Interestingly, YXS upregulated endogenous nuclear receptors including LXRα, PPARα, PPARβ and ERα, and in-vivo knockdown of cardiac-specific LXRα significantly blunted the cardio-protective effects of YXS. Collectively, these data show that YXS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and oxidative stress and by upregulating LXRα, thereby providing a rationale for future clinical trials and clinical applications.

Environmental exposure to lead induces oxidative stress and modulates the function of the antioxidant defense system and the immune system in the semen of males with normal semen profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasperczyk, Aleksandra; Dobrakowski, Michał; Czuba, Zenon P.

We investigated the associations between environmental exposure to lead and a repertoire of cytokines in seminal plasma of males with normal semen profile according to the WHO criteria. Based on the median lead concentration in seminal plasma, 65 samples were divided into two groups: low (LE) and high exposure to lead (HE). Differences in semen volume and the pH, count, motility and morphology of sperm cells were not observed between the examined groups. The total oxidant status value and the level of protein sulfhydryl groups as well as the activities of manganese superoxide dismutase and catalase were significantly higher inmore » the HE group, whereas the total antioxidant capacity value and the activities of glutathione reductase and glutathione-S-transferase were depressed. IL-7, IL-10, IL-12, and TNF-α levels were significantly higher in the HE group compared with the LE group. Environmental exposure to lead is sufficient to induce oxidative stress in seminal plasma and to modulate antioxidant defense system. - Highlights: • Lead induces oxidative stress in seminal plasma in human. • Lead modulates antioxidant defense system in seminal plasma in human. • Lead does not change a Th1/Th2 imbalance in seminal plasma in human.« less

The affection of the disturbance of the hydrodynamics of blood in case of stress on pathological increase of level of low density lipoproteins in blood. The formation of cylindrical plaques, and their participation in the development of acute ischemic disorders of heart and brain.

PubMed

Rusanov, S E

2017-09-01

In this article is given the new insight about the affection of stress on the increase of level of low density lipoproteins (LDL) in the blood, which is connected with the disturbance of hydrodynamics in the bloodstream, the attention was paid to the cylindrical cholesterol plaque, and it's classification. The disturbance of hydrodynamics of blood under the stress leads to the formation of a cylindrical cholesterol plaque, which repeats the contour of the vessel, and leads to the ischemic disorders of the heart and brain. The cylindrical cholesterol plaque goes through several stages of development: friable, yielding, dense, old. In the case of destruction of friable, fresh cholesterol plaque, releases a big quantity of low-density lipoproteins. This leads to the pathological increase of level of LDL in the blood. In the case of long disturbance of hydrodynamics, occurs the formation of strong links between low-density lipoproteins. Yielding cholesterol plaque is formed. Further maturation of cylindrical cholesterol plaque, leads to it's densifying and damage. We may emphasize, that short periods of strong contraction and expansion of vessels lead to the increase of level of LDL in the blood. Self-dependent restoration of normal level of LDL in blood occurs in the case of restoration of pressure in the limits of numbers, which are specific for particular person, and which don't exceed the physiological standard. Among patients with long duration of stress, the duration of vasospasm increases. LDL, without having a possibility to crumble, begin to stick together and form the yielding cylindrical plaque. It is characterized by having of not so strong connection with the vascular wall, and maintains only at the expanse of iteration of the vascular wall, it has cylindrical shape, is elastic and yellow. The thickness and length of walls depends on the degree of cross-clamping during the time of formation of yielding cylindrical plaque. In the case of stopping of spasm, yielding cylindrical plaque can resolve slowly. Among hypotensive and individuals, which have normal pressure, the increase of level of LDL isn't noted. There aren't such investigations, where such link was noted. The increasing of level of LDL among these people (especially under the stress) can say about cases of short-term increase of pressure, which could be unnoticed. These patients require pressure monitoring and, accordingly, the adjustment of the state of stress and anger. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

NASA Astrophysics Data System (ADS)

Alatawneh, Natheer; Rahman, Tanvir; Lowther, David A.; Chromik, Richard

2017-06-01

Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

NASA Astrophysics Data System (ADS)

Oomen, Marijn; Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea

2012-11-01

We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

Biological Stress Systems, Adverse Life Events, and the Improvement of Chronic Multisite Musculoskeletal Pain Across a 6-Year Follow-Up.

PubMed

Generaal, Ellen; Vogelzangs, Nicole; Macfarlane, Gary J; Geenen, Rinie; Smit, Johannes H; de Geus, Eco J C N; Dekker, Joost; Penninx, Brenda W J H

2017-02-01

Dysfunction of biological stress systems and adverse life events, independently and in interaction, have been hypothesized to predict chronic pain persistence. Conversely, these factors may hamper the improvement of chronic pain. Longitudinal evidence is currently lacking. We examined whether: 1) function of biological stress systems, 2) adverse life events, and 3) their combination predict the improvement of chronic multisite musculoskeletal pain. Subjects of the Netherlands Study of Depression and Anxiety (NESDA) with chronic multisite musculoskeletal pain at baseline (N = 665) were followed-up 2, 4, and 6 years later. The Chronic Pain Grade Questionnaire was used to determine improvement (not meeting the criteria) of chronic multisite musculoskeletal pain at follow-up. Baseline assessment of biological stress systems included function of hypothalamic-pituitary-adrenal axis (1-hour cortisol awakening response, evening level, and post dexamethasone level), the immune system (basal and lipopolysaccharide-stimulated inflammatory markers), the autonomic nervous system (heart rate, pre-ejection period, SD of the normal-to-normal interval, and respiratory sinus arrhythmia). The number of adverse life events were assessed at baseline and 2-year follow-up using the List of Threatening Events Questionnaire. We showed that hypothalamic-pituitary-adrenal axis, immune system, and autonomic nervous system functioning and adverse life events were not associated with the improvement of chronic multisite musculoskeletal pain, either as a main effect or in interaction. This longitudinal study could not confirm that biological stress system dysfunction and adverse life events affect the course of chronic multisite musculoskeletal pain. Biological stress systems and adverse life events are not associated with the improvement of chronic multisite musculoskeletal pain over 6 years of follow-up. Other determinants should thus be considered in future research to identify in which persons pain symptoms will improve. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Laboratory observations of fault strength in response to changes in normal stress

USGS Publications Warehouse

Kilgore, Brian D.; Lozos, Julian; Beeler, Nicholas M.; Oglesby, David

2012-01-01

Changes in fault normal stress can either inhibit or promote rupture propagation, depending on the fault geometry and on how fault shear strength varies in response to the normal stress change. A better understanding of this dependence will lead to improved earthquake simulation techniques, and ultimately, improved earthquake hazard mitigation efforts. We present the results of new laboratory experiments investigating the effects of step changes in fault normal stress on the fault shear strength during sliding, using bare Westerly granite samples, with roughened sliding surfaces, in a double direct shear apparatus. Previous experimental studies examining the shear strength following a step change in the normal stress produce contradictory results: a set of double direct shear experiments indicates that the shear strength of a fault responds immediately, and then is followed by a prolonged slip-dependent response, while a set of shock loading experiments indicates that there is no immediate component, and the response is purely gradual and slip-dependent. In our new, high-resolution experiments, we observe that the acoustic transmissivity and dilatancy of simulated faults in our tests respond immediately to changes in the normal stress, consistent with the interpretations of previous investigations, and verify an immediate increase in the area of contact between the roughened sliding surfaces as normal stress increases. However, the shear strength of the fault does not immediately increase, indicating that the new area of contact between the rough fault surfaces does not appear preloaded with any shear resistance or strength. Additional slip is required for the fault to achieve a new shear strength appropriate for its new loading conditions, consistent with previous observations made during shock loading.

Confinement of NORMAL- AND HIGH-STRENGTH CONCRETE by Shape Memory Alloy (SMA) Spirals

NASA Astrophysics Data System (ADS)

Gholampour, A.; Ozbakkaloglu, T.

2018-01-01

This paper presents the results of an experimental study on the axial compressive behaviour of normal- and high-strength concrete (NSC and HSC) confined by shape memory alloy (SMA) spirals. A spiral pitch space of 36 and 20 mm was used for SMA confinement of NSC and HSC columns, respectively. The confining pressure was applied on the concrete cylinders by SMA spirals that were prestrained at 0, 5.5, and 9.5%. The compression test results on the SMA-confined specimens indicate that the prestrain level of SMA significantly affects the axial compressive behaviour of both NSC and HSC. An increase in the level of prestrain leads to an increase in the peak axial stress and corresponding strain of SMA-confined concrete.

Caspase-12 ablation preserves muscle function in the mdx mouse

PubMed Central

Moorwood, Catherine; Barton, Elisabeth R.

2014-01-01

Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin. Several downstream consequences of dystrophin deficiency are triggers of endoplasmic reticulum (ER) stress, including loss of calcium homeostasis, hypoxia and oxidative stress. During ER stress, misfolded proteins accumulate in the ER lumen and the unfolded protein response (UPR) is triggered, leading to adaptation or apoptosis. We hypothesized that ER stress is heightened in dystrophic muscles and contributes to the pathology of DMD. We observed increases in the ER stress markers BiP and cleaved caspase-4 in DMD patient biopsies, compared with controls, and an increase in multiple UPR pathways in muscles of the dystrophin-deficient mdx mouse. We then crossed mdx mice with mice null for caspase-12, the murine equivalent of human caspase-4, which are resistant to ER stress. We found that deleting caspase-12 preserved mdx muscle function, resulting in a 75% recovery of both specific force generation and resistance to eccentric contractions. The compensatory hypertrophy normally found in mdx muscles was normalized in the absence of caspase-12; this was found to be due to decreased fibre sizes, and not to a fibre type shift or a decrease in fibrosis. Fibre central nucleation was not significantly altered in the absence of caspase-12, but muscle fibre degeneration found in the mdx mouse was reduced almost to wild-type levels. In conclusion, we have identified heightened ER stress and abnormal UPR signalling as novel contributors to the dystrophic phenotype. Caspase-4 is therefore a potential therapeutic target for DMD. PMID:24879640

Protective effect of aqueous seed extract of Vitis Vinifera against oxidative stress, inflammation and apoptosis in the pancreas of adult male rats with diabetes mellitus.

PubMed

Adam, Siti Hajar; Giribabu, Nelli; Kassim, Normadiah; Kumar, Kilari Eswar; Brahmayya, Manuri; Arya, Aditya; Salleh, Naguib

2016-07-01

Protective effects of Vitis Vinifera seed aqueous extract (VVSAE) against pancreatic dysfunctions and elevation of oxidative stress, inflammation and apoptosis in the pancreas in diabetes were investigated. Histopathological changes in the pancreas were examined under light microscope. Blood and pancreas were collected from adult male diabetic rats receiving 28days treatment with VVSAE orally. Fasting blood glucose (FBG), glycated hemoglobin (HbA1c), insulin and lipid profile levels and activity levels of anti-oxidative enzymes (superoxide dismutase-SOD, catalase-CAT and glutathione peroxidase-GPx) in the pancreas were determined by biochemical assays. Histopathological changes in the pancreas were examined under light microscopy and levels of insulin, glucose transporter (GLUT)-2, tumor necrosis factor (TNF)-α, Ikkβ and caspase-3 mRNA and protein were analyzed by real-time PCR (qPCR) and immunohistochemistry respectively. Radical scavenging activity of VVSAE was evaluated by in-vitro anti-oxidant assay while gas chromatography-mass spectrometry (GC-MS) was used to identify the major compounds in the extract. GC-MS analyses indicated the presence of compounds that might exert anti-oxidative, anti-inflammatory and anti-apoptosis effects. Near normal FBG, HbAIc, lipid profile and serum insulin levels with lesser signs of pancreatic destruction were observed following administration of VVSAE to diabetic rats. Higher insulin, GLUT-2, SOD, CAT and GPx levels but lower TNF-α, Ikkβ and caspase-3 levels were also observed in the pancreas of VVSAE-treated diabetic rats (p<0.05 compared to non-treated diabetic rats). The extract possesses high in-vitro radical scavenging activities. In conclusions, administration of VVSAE to diabetic rats could help to protect the pancreas against oxidative stress, inflammation and apoptosis-induced damage while preserving pancreatic function near normal in diabetes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Use of structured personality survey techniques to indicate operator response to stressful situations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waller, M.A.

Under given circumstances, a person will tend to operate in one of four dominant orientations: (1) to perform tasks; (2) to achieve consensus; (3) to achieve understanding, or (4) to maintain structure. Historically, personality survey techniques, such as the Myers-Briggs type indicator, have been used to determine these tendencies. While these techniques can accurately reflect a person's orientation under normal social situations, under different sets of conditions, the same person may exhibit other tendencies, displaying a similar or entirely different orientation. While most do not exhibit extreme tendencies or changes of orientation, the shift in personality from normal to stressfulmore » conditions can be rather dramatic, depending on the individual. Structured personality survey techniques have been used to indicate operator response to stressful situations. These techniques have been extended to indicate the balance between orientations that the control room team has through the various levels of cognizance.« less

Hyperglycemia: a bad signature on the vascular system

PubMed Central

Costantino, Sarah; Paneni, Francesco

2015-01-01

Experimental work has clearly demonstrated that hyperglycemia is able to derail molecular pathways favouring oxidative stress, inflammation and endothelial dysfunction. Consistently, pooled analyses from prospective studies provide strong evidence that glycemic markers, namely glycated haemoglobin (HbA1c), predict cardiovascular risk, with an increase of about 18% in risk for each 1% absolute increase in HbA1c concentration, regardless of classical risk factors. Although the importance of hyperglycemic burden on cardiovascular phenotype, normalization of blood glucose levels in patients with long-standing hyperglycemia does not seem to reduce macrovascular complications. These data suggest that hyperglycemia may exert long-lasting detrimental effects on the cardiovascular system. This emerging phenomenon is defined metabolic or hyperglycemic memory to indicate a long-term persistence of hyperglycemic stress, even after blood glucose normalization. Here, we discuss clinical evidence and potential molecular mechanisms implicated in metabolic memory and, hence, diabetes-related cardiovascular complications. PMID:26543827

Effect of radiation on red cell membrane and intracellular oxidative defense systems.

PubMed

Katz, D; Mazor, D; Dvilansky, A; Meyerstein, N

1996-03-01

Ionizing radiation is currently used for prevention of transfusion associated graft versus host disease (TAGVHD). As radiation damage is associated with the production of activated oxygen species, the aim of this study was to observe the immediate effect of ionizing radiation on red cell membrane and intracellular oxidative defense systems. Neonatal and iron deficiency (IDA) cells, known for their increased sensitivity to oxidative stress, were chosen and compared with normal cells. Irradiation was performed in doses of 1500 cGy, 3000 cGy and 5000 cGy. GSH and methemoglobin levels and the activity of different antioxidant enzymes, measured under optimal in vitro conditions, were preserved in all cells after irradiation. Only radiation at the highest does of 5000 cGy, caused significant potassium leakage in neonatal cells and insignificant increase in IDA cells. Thus, cells with increased sensitivity to oxidative stress are more susceptible to damage by ionizing radiation than normal cells.

Investigating the role of nisoldipine in foot-shock-induced post-traumatic stress disorder in mice.

PubMed

Verma, Meenu; Bali, Anjana; Singh, Nirmal; Jaggi, Amteshwar S

2016-04-01

This study was designed to investigate the effectiveness of nisoldipine, an L-type voltage-sensitive calcium channel blocker, to ameliorate anxiety and fear response in a mouse model of post-traumatic stress disorder (PTSD). Acute trauma was induced in Swiss albino mice in a 2-day electric foot-shock paradigm consisting of 15 intermittent foot-shocks of 0.8 mA intensity, 10-s duration and 10-s intershock interval, during 5 min, followed by 3 weekly situational reminders, that is, once per week in the same context on three successive weeks. PTSD-induced behavioral changes were assessed using actophotometer, open-field, social interaction test, and freezing behavior. Biochemically, the serum corticosterone levels were estimated. Electric foot-shock and situational reminders produced behavioral alterations and decreased corticosterone levels, assessed on the 21st day following the traumatic event. Administration of sertraline (Ser 15 mg/kg), a selective serotonin reuptake inhibitor (SSRI) and nisoldipine (20 and 40 mg/kg), significantly attenuated the foot-shock-trauma-induced behavioral changes along with normalization of the corticosterone levels. It may be concluded that nisoldipine produces beneficial effects in re-establishing behavioral alterations, which may be due to normalization of reduced corticosterone levels in PTSD in mice. © 2015 Société Française de Pharmacologie et de Thérapeutique.

The Wheat NAC Transcription Factor TaNAC2L Is Regulated at the Transcriptional and Post-Translational Levels and Promotes Heat Stress Tolerance in Transgenic Arabidopsis.

PubMed

Guo, Weiwei; Zhang, Jinxia; Zhang, Ning; Xin, Mingming; Peng, Huiru; Hu, Zhaorong; Ni, Zhongfu; Du, Jinkun

2015-01-01

Heat stress poses a serious threat to global crop production. In efforts that aim to mitigate the adverse effects of heat stress on crops, a variety of genetic tools are being used to develop plants with improved thermotolerance. The characterization of important regulators of heat stress tolerance provides essential information for this aim. In this study, we examine the wheat (Triticum aestivum) NAC transcription factor gene TaNAC2L. High temperature induced TaNAC2L expression in wheat and overexpression of TaNAC2L in Arabidopsis thaliana enhanced acquired heat tolerance without causing obvious alterations in phenotype compared with wild type under normal conditions. TaNAC2L overexpression also activated the expression of heat-related genes in the transgenic Arabidopsis plants, suggesting that TaNAC2L may improve heat tolerance by regulating the expression of stress-responsive genes. Notably, TaNAC2L is also regulated at the post-translational level and might be degraded via a proteasome-mediated pathway. Thus, this wheat transcription factor may have potential uses in enhancing thermotolerance in crops.

Oxidative stress and plasma lipoproteins in cancer patients

PubMed Central

Maia, Fernanda Maria Machado; Santos, Emanuelly Barbosa; Reis, Germana Elias

2014-01-01

Objective To evaluate the relation between oxidative stress and lipid profile in patients with different types of cancer. Methods This was an observational cross-sectional. A total of 58 subjects were evaluated, 33 males, divided into two groups of 29 patients each: Group 1, patients with cancer of the digestive tract and accessory organs; Group 2 patients with other types of cancers, all admitted to a public hospital. The plasma levels (lipoproteins and total cholesterol, HDL, and triglycerides, for example) were analyzed by enzymatic kits, and oxidative stress based on thiobarbituric acid-reactive substances, by assessing the formation of malondialdehyde. Results In general the levels of malondialdehyde of patients were high (5.00μM) as compared to 3.31μM for healthy individuals. The median values of lipids exhibited normal triacylglycerol (138.78±89.88mg/dL), desirable total cholesterol values (163.04±172.38mg/dL), borderline high LDL (151.30±178.25mg/dL) and low HDL (31.70±22.74mg/dL). Median HDL levels in Group 1 were lower (31.32mg/dL) than the cancer patients in Group 2 (43.67mg/dL) (p=0.038). Group 1 also showed higher levels of oxidative stress (p=0.027). Conclusion The lipid profile of patients with cancer was not favorable, which seems to have contributed to higher lipid peroxidation rate, generating a significant oxidative stress. PMID:25628201

Testing Plastic Deformations of Materials in the Introductory Undergraduate Mechanics Laboratory

ERIC Educational Resources Information Center

Romo-Kroger, C. M.

2012-01-01

Normally, a mechanics laboratory at the undergraduate level includes an experiment to verify compliance with Hooke's law in materials, such as a steel spring and an elastic rubber band. Stress-strain curves are found for these elements. Compression in elastic bands is practically impossible to achieve due to flaccidity. A typical experiment for…

METRO-APEX Volume 17.1: Industrialist's Manual No. 7, Shick Cannery. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 7 (Shick Cannery) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of…

METRO-APEX Volume 19.1: City Manager and County Administrative Officer's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The City Manager and County Administrative Officer's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an…

METRO-APEX Volume 13.1: Industrialist's Manual No. 3, Rusty's Iron Foundry. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 3 (Rusty's Iron Foundry) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion…

METRO-APEX Volume 7.1: Air Pollution Control Officer's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Air Pollution Control Officer's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air…

METRO-APEX Volume 11.1: Industrialists' Manual No. 1, Shear Power Company. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 1 (Shear Power Company) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion…

METRO-APEX Volume 12.1: Industrialist's Manual No. 2, People's Pulp Plant. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 2 (People's Pulp Plant) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion…

METRO-APEX Volume 15.1: Industrialist's Manual No. 5, Caesar's Rendering Plant. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 5 (Caesar's Rendering Plant) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an…

METRO-APEX Volume 16.1: Industrialist's Manual No. 6, Dusty Rhodes Cement Company. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 6 (Dusty Rhodes Cement Company) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an…

METRO-APEX Volume 14.1: Industrialist's Manual No. 4, Gestalt Malt Brewery. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Industrialist's Manual No. 4 (Gestalt Malt Brewery) is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion…

Physical Properties Of Acupuncture Needles: Do Disposable Acupuncture Needles Break With Normal Use

DTIC Science & Technology

2016-06-01

Lamb shank, which has complexity of tendon, fascia, and bone, was used to mimic human tissue. The needles (n=10) were stressed in the tissue substitute...needles were re-imaged after stressing and visually assessed. RESULTS: Only one manufacturing scuff mark was noted out of 90 needles before stress ...testing. Needles buckled but did not break when they were stressed beyond normal clinical use. No cracks or fractures were noted after stress

Interdependency between mechanical parameters and afferent nerve discharge in remodeled diabetic Goto-Kakizaki rat intestine

PubMed Central

Zhao, Jingbo; Yang, Jian; Liao, Donghua; Gregersen, Hans

2017-01-01

Background Gastrointestinal disorders are very common in diabetic patients, but the pathogenesis is still not well understood. Peripheral afferent nerves may be involved due to the complex regulation of gastrointestinal function by the enteric nervous system. Objective We aimed to characterize the stimulus–response function of afferent fibers innervating the jejunum in the Goto-Kakizaki (GK) type 2 diabetic rat model. A key question is whether changes in afferent firing arise from remodeled tissue or from adaptive afferent processes. Design Seven 32-week-old male GK rats and seven age-matched normal Wistar rats were studied. Firing from mesenteric afferent nerves was recorded in excised jejunal segments of seven GK rats and seven normal Wistar rats during ramp test, stress relaxation test, and creep test. The circumferential stress–strain, spike rate increase ratio (SRIR), and single unit firing rates were calculated for evaluation of interdependency of the mechanical stimulations and the afferent nerve discharge. Results Elevated sensitivity to mechanical stimuli was found for diabetic nerve bundles and single unit activity (P<0.05). The stress relaxed less in the diabetic intestinal segment (P<0.05). Linear association between SRIR and the thickness of circumferential muscle layer was found at high stress levels as well as for SRIR and the glucose level. Conclusion Altered viscoelastic properties and elevated mechanosensitivity were found in the GK rat intestine. The altered nerve signaling is related to muscle layer remodeling and glucose levels and may contribute to gastrointestinal symptoms experienced by diabetic patients. PMID:29238211

Transient ventricular dysfunction after an asphyxiation event: stress or hypoxia?

PubMed

Valletta, Mary E; Haque, Ikram; Al-Mousily, Faris; Udassi, Jai; Saidi, Arwa

2008-11-01

This report of a pediatric patient with acute upper airway obstruction causing asphyxiation emphasizes the need to maintain clinical suspicion for acquired myocardial dysfunction, despite the presumed role of noncardiogenic causes for pulmonary edema after an acute upper airway obstruction. Case report. A tertiary pediatric intensive care unit. A 10-year-old girl with no significant medical history who developed flash pulmonary edema and acute myocardial dysfunction after an acute upper airway obstruction. Serial echocardiograms, exercise stress test, and coronary angiography were performed. Serial pro-brain natriuretic peptide, troponins, and CK-MB levels were also followed. Troponin level normalized approximately 7 days after the acute event. CK-MB and pro-brain natriuretic peptide levels decreased but had not completely normalized by time of discharge. The patient was discharged home 10 days after the event on an anticipated 6-month course of metoprolol without any signs or symptoms of cardiac dysfunction. Myocardial dysfunction is rarely documented in children after an acute upper airway obstruction or an asphyxiation event. Pediatric intensivists and hospitalists should maintain a high degree of clinical suspicion and screen for possible myocardial dysfunction in the pediatric patient with an acute severe hypoxic event especially when accompanied by pulmonary edema. Prompt evaluation ensures appropriate support. Additionally, some role may exist for early adrenergic receptor blockade.

Static and kinetic friction of granite at high normal stress

USGS Publications Warehouse

Byerlee, J.D.

1970-01-01

Frictional sliding on ground surfaces of granite, angle of sliding planes 30?? and 45??, was investigated as a function of confining pressure. Over the normal stress range of 2-12 kb, the static frictional shear stress ??s follows the relationship ??s = 0??5 + 0?? ??n and the kinetic frictional shear stress ??k was calculated to be ??k = 0??25 + 0??47 ??n. ?? 1970.

ATR-like kinase Mec1 facilitates both chromatin accessibility at DNA replication forks and replication fork progression during replication stress

PubMed Central

Rodriguez, Jairo; Tsukiyama, Toshio

2013-01-01

Faithful DNA replication is essential for normal cell division and differentiation. In eukaryotic cells, DNA replication takes place on chromatin. This poses the critical question as to how DNA replication can progress through chromatin, which is inhibitory to all DNA-dependent processes. Here, we developed a novel genome-wide method to measure chromatin accessibility to micrococcal nuclease (MNase) that is normalized for nucleosome density, the NCAM (normalized chromatin accessibility to MNase) assay. This method enabled us to discover that chromatin accessibility increases specifically at and ahead of DNA replication forks in normal S phase and during replication stress. We further found that Mec1, a key regulatory ATR-like kinase in the S-phase checkpoint, is required for both normal chromatin accessibility around replication forks and replication fork rate during replication stress, revealing novel functions for the kinase in replication stress response. These results suggest a possibility that Mec1 may facilitate DNA replication fork progression during replication stress by increasing chromatin accessibility around replication forks. PMID:23307868

Branched-chain amino acids attenuate early kidney injury in diabetic rats.

PubMed

Mi, Na; Zhang, Xiu Juan; Ding, Yan; Li, Guo Hua; Wang, Wei Dong; Xian, Hui Xia; Xu, Jin

2015-10-16

Diabetic nephropathy (DN) is the most severe diabetic microvascular complication. The pathogenesis of diabetic nephropathy is complex, and oxidative stress plays an important role in the development of diabetic nephropathy. Elevated reactive oxygen species (ROS) levels activate various signaling pathways and influence the activities of transforming growth factor-β (TGF-β) and matrix metalloproteinase-9 (MMP-9), which contributes to glomerular hypertrophy. Branched-chain amino acids (BCAAs) are widely used in clinical treatment, and BCAAs can reduce the oxidative stress associated with the diabetic pancreas and some liver diseases. Thus, the aim of the present study was to determine whether BCAAs could attenuate oxidative stress in the kidneys of streptozotocin (STZ)-induced diabetic rats to prevent early diabetic kidney injury. Male Wistar rats were fed for two weeks with a normal chow diet or a high-fat diet in which 40% of calories were derived from fat. After this two-week period, the mice fed normal chow were injected with vehicle, while the high-fat diet group was injected intraperitoneally (i.p.) with 40 mg/kg STZ. The STZ-treated group was randomly divided into four subgroups that were treated with different doses of BCAAs or vehicle for two months by oral gavage. Plasma glucose, plasma creatinine, urinary protein and JNK, TGF-β, and MMP-9 mRNA and protein expression levels were measured in the rats. The ROS levels and proteinuria in the STZ-induced diabetic rats were significantly higher than those in the control groups. Moreover, early kidney injury occurred in the STZ-induced diabetic rats. However, BCAAs treatment decreased ROS levels, proteinuria and kidney injury. Moreover, JNK, TGF-β and MMP-9 mRNA and protein levels were significantly increased in the diabetic rats when compared with the control rats, and BCAAs treatment reversed these changes. Our results suggest that BCAAs counter oxidative stress in the kidneys of diabetic rats and alleviate diabetic kidney injury via the JNK/TGF-β/MMP-9 pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

Cardiac Uptake of Minocycline and Mechanisms for In Vivo Cardioprotection

PubMed Central

Romero-Perez, Diego; Fricovsky, Eduardo; Yamasaki, Katrina Go; Griffin, Michael; Barraza-Hidalgo, Maraliz; Dillmann, Wolfgang; Villarreal, Francisco

2008-01-01

Objectives The ability of minocycline to be transported into cardiac cells, concentrate in normal and ischemic myocardium and act as in vivo cardioprotector was examined. We also determined minocycline's capacity to act as a reducer of myocardial oxidative stress and matrix metalloproteinase (MMP) activity. Background The identification of compounds with the potential to reduce myocardial ischemic injury is of great interest. Tetracyclines (TTCs) are antibiotics with pleiotropic cytoprotective properties that accumulate in normal and diseased tissues. Minocycline is highly lipophilic and has shown promise as a possible cardioprotector. However, minocycline's potential as an in vivo cardioprotector as well as the means by which this action is attained are not well understood. Methods Rats were subjected to 45 min of ischemia and 48 h of reperfusion. Animals were treated 48 h before and 48 h after thoracotomy with either vehicle or 50 mg/kg/day minocycline. Tissue samples were used for biochemical assays and cultured cardiac cells for minocycline uptake experiments. Results Minocycline significantly reduced infarct size (∼33%), tissue MMP-9 activity and oxidative stress. Minocycline was concentrated ∼24-fold in normal (0.5 mM) and ∼50-fold in ischemic regions (1.1 mM) vs. blood. Neonatal rat cardiac fibroblasts, myocytes and adult fibroblasts demonstrate a time- and temperature-dependent uptake of minocycline to levels that approximate those of normal myocardium. Conclusions Given the high intracellular levels observed and results from the assessment of in vitro antioxidant and MMP inhibitor capacities, it is likely that minocycline acts to limit myocardial ischemic injury via mass action effects. PMID:18848143

Surgical treatment of diaphyseal stress fractures of the fifth metatarsal in competitive athletes: long-term follow-up and computerized pedobarographic analysis.

PubMed

Pecina, Marko; Bojanic, Ivan; Smoljanovic, Tomislav; Ivkovic, Alan; Mirkovic, Maja; Jelic, Miroslav

2011-01-01

Proximal diaphyseal stress fractures of the fifth metatarsal are common in athletes. Conservative treatment has been shown to result in high rates of delayed union, nonunion, and refracture, so internal fixation has become the treatment of choice in competitive athletes. Twenty top-level athletes with diaphyseal stress fractures fixed with intramedullary malleolar screws were evaluated. Functional outcome was assessed by American Orthopaedic Foot and Ankle Society midfoot score. Static and dynamic maximum vertical force and peak plantar pressures were evaluated with a computerized pedobarograph. Mean follow-up from surgery to interview was 10.3 years (range, 3.5-19.0 years). Clinical healing was 95%, and there has been one refracture (5%). The mean time from surgery to return to sport was 9 weeks (range, 5-14 weeks). Twelve athletes (60%) returned to a higher level of training, 7 (35%) to the same level, and 1 (5%) to a lower level compared with the level of training before injury. Average American Orthopaedic Foot and Ankle Society midfoot score was 93.8 (range, 85-100). During the computerized pedobarographic evaluations, 18 patients (90%) presented with varus of the metatarsus and the midfoot and 2 (10%) presented with a normal plantigrade foot. Intramedullary malleolar screws can yield reliable and effective healing of fifth metatarsal stress fractures in athletes. Varus of the metatarsus and the midfoot were predisposing factors for stress fractures in this population of competitive athletes, and all were recommended to wear orthoses until their competitive careers were completed.

Anti-oxidant and anti-inflammatory effects of apigenin in a rat model of sepsis: an immunological, biochemical, and histopathological study.

PubMed

Karamese, Murat; Erol, Huseyin Serkan; Albayrak, Mevlut; Findik Guvendi, Gulname; Aydin, Emsal; Aksak Karamese, Selina

2016-06-01

We hypothesize that apigenin may inhibit some cellular process of sepsis-induced spleen injury and simultaneously improve inflammation and oxidative stress. Therefore, the aim of this study was to investigate the potential protective effects of apigenin in a polymicrobial sepsis rat model of by cecal ligation and puncture. 64 female Wistar albino rats were divided into 8 groups. The pro-inflammatory (tumor necrosis factor-alpha, interleukin-6, and interleukin-1-beta) and anti-inflammatory (tumor growth factor-beta and interleukin-10) cytokine levels were measured by enzyme-linked immunosorbent assay. CD3, CD68, and nuclear factor kappa B (NF-κB) positivity rates were detected by immunohistochemical methods. Oxidative stress parameters were measured by tissue biochemistry. Sepsis caused a significant increase in TNF-alpha, IL-1-beta, IL-6, and TGF-beta levels whereas it reduced IL-10 level. Additionally, it led to an increase in CD3, CD68, and NF-κB positivity rates as well as oxidative stress parameters levels. However, apigenin inhibited the inflammation process, increased the IL-10 level and normalized the oxidative stress parameters. Pretreatment with apigenin results in a significant reduction in the amount of inflammatory cells. The beneficial effect of apigenin on spleen injury also involved inhibition of NF-κB pathway, suppression of proinflammatory cytokines, and induction of anti-inflammatory cytokine production. Additionally, it led to a decrease in oxidative stress in spleen tissue. Taking everything into account, apigenin may be an alternative therapeutic option for prevention of sepsis-induced organ.

Effects of maternal stress and perinatal fluoxetine exposure on behavioral outcomes of adult male offspring.

PubMed

Kiryanova, V; Meunier, S J; Vecchiarelli, H A; Hill, M N; Dyck, R H

2016-04-21

Women of child-bearing age are the population group at highest risk for depression. In pregnant women, fluoxetine (Flx) is the most widely prescribed selective serotonin reuptake inhibitor (SSRI) used for the treatment of depression. While maternal stress, depression, and Flx exposure have been shown to effect neurodevelopment of the offspring, separately, combined effects of maternal stress and Flx exposure have not been extensively examined. The present study investigated the effects of prenatal maternal stress and perinatal exposure to the SSRI Flx on the behavior of male mice as adults. C57BL/6 dams exposed to chronic unpredictable stress from embryonic (E) day 4 to E18 and non-stressed dams were administered Flx (25 mg/kg/d) in the drinking water from E15 to postnatal day 12. A separate control group consisted of animals that were not exposed to stress or Flx. At 12 days of age, brain levels of serotonin were assessed in the male offspring. At two months of age, the male offspring of mothers exposed to prenatal stress (PS), perinatal Flx, PS and Flx, or neither PS or Flx, went through a comprehensive behavioral test battery. At the end of testing brain-derived neurotropic factor (BDNF) levels were assessed in the frontal cortex of the offspring. Maternal behavior was not altered by either stress or Flx treatment. Treatment of the mother with Flx led to detectible Flx and NorFlx levels and lead to a decrease in serotonin levels in pup brains. In the adult male offspring, while perinatal exposure to Flx increased aggressive behavior, prenatal maternal stress decreased aggressive behavior. Interestingly, the combined effects of stress and Flx normalized aggressive behavior. Furthermore, perinatal Flx treatment led to a decrease in anxiety-like behavior in male offspring. PS led to hyperactivity and a decrease in BDNF levels in the frontal cortex regardless of Flx exposure. Neither maternal stress or Flx altered offspring performance in tests of cognitive abilities, memory, sensorimotor information processing, or risk assessment behaviors. These results demonstrate that maternal exposure to stress and Flx have a number of sustained effects on the male offspring. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Blunted Myocardial Oxygenation Response During Vasodilator Stress in Patients With Hypertrophic Cardiomyopathy

PubMed Central

Karamitsos, Theodoros D.; Dass, Sairia; Suttie, Joseph; Sever, Emily; Birks, Jacqueline; Holloway, Cameron J.; Robson, Matthew D.; Jerosch-Herold, Michael; Watkins, Hugh; Neubauer, Stefan

2013-01-01

Objectives This study sought to assess myocardial perfusion and tissue oxygenation during vasodilator stress in patients with overt hypertrophic cardiomyopathy (HCM), as well as in HCM mutation carriers without left ventricular (LV) hypertrophy, and to compare findings to those in athletes with comparable hypertrophy and normal controls. Background Myocardial perfusion under vasodilator stress is impaired in patients with HCM. Whether this is associated with impaired myocardial oxygenation and tissue ischemia is unknown. Furthermore, it is not known whether perfusion and oxygenation are impaired in HCM mutation carriers without left ventricular hypertrophy (LVH). Methods A total of 27 patients with overt HCM, 10 HCM mutation carriers without LVH, 11 athletes, and 20 healthy controls underwent cardiovascular magnetic resonance (CMR) scanning at 3-T. Myocardial function, perfusion (perfusion reserve index [MPRI]), and oxygenation (blood-oxygen level dependent signal intensity [SI] change) under adenosine stress were assessed. Results MPRI was significantly reduced in HCM (1.3 ± 0.1) compared to controls (1.8 ± 0.1, p < 0.001) and athletes (2.0 ± 0.1, p < 0.001), but remained normal in HCM mutation carriers without LVH (1.7 ± 0.1; p = 0.61 vs. controls, p = 0.02 vs. overt HCM). Oxygenation response was attenuated in overt HCM (SI change 6.9 ± 1.4%) compared to controls (18.9 ± 1.4%, p < 0.0001) and athletes (18.7 ± 2.0%, p < 0.001). Interestingly, HCM mutation carriers without LVH also showed an impaired oxygenation response to adenosine (10.4 ± 2.0%; p = 0.001 vs. controls, p = 0.16 vs. overt HCM, p = 0.003 vs. athletes). Conclusions In overt HCM, both perfusion and oxygenation are impaired during vasodilator stress. However, in HCM mutation carriers without LVH, only oxygenation is impaired. In athletes, stress perfusion and oxygenation are normal. CMR assessment of myocardial oxygenation has the potential to become a novel risk factor in HCM. PMID:23498131

Type 2 diabetes mellitus induces congenital heart defects in murine embryos by increasing oxidative stress, endoplasmic reticulum stress, and apoptosis.

PubMed

Wu, Yanqing; Reece, E Albert; Zhong, Jianxiang; Dong, Daoyin; Shen, Wei-Bin; Harman, Christopher R; Yang, Peixin

2016-09-01

Maternal type 1 and 2 diabetes mellitus are strongly associated with high rates of severe structural birth defects, including congenital heart defects. Studies in type 1 diabetic embryopathy animal models have demonstrated that cellular stress-induced apoptosis mediates the teratogenicity of maternal diabetes leading to congenital heart defect formation. However, the mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects remain largely unknown. We aim to determine whether oxidative stress, endoplasmic reticulum stress, and excessive apoptosis are the intracellular molecular mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects. A mouse model of maternal type 2 diabetes mellitus was established by feeding female mice a high-fat diet (60% fat). After 15 weeks on the high-fat diet, the mice showed characteristics of maternal type 2 diabetes mellitus. Control dams were either fed a normal diet (10% fat) or the high-fat diet during pregnancy only. Female mice from the high-fat diet group and the 2 control groups were mated with male mice that were fed a normal diet. At E12.5, embryonic hearts were harvested to determine the levels of lipid peroxides and superoxide, endoplasmic reticulum stress markers, cleaved caspase 3 and 8, and apoptosis. E17.5 embryonic hearts were harvested for the detection of congenital heart defect formation using India ink vessel patterning and histological examination. Maternal type 2 diabetes mellitus significantly induced ventricular septal defects and persistent truncus arteriosus in the developing heart, along with increasing oxidative stress markers, including superoxide and lipid peroxidation; endoplasmic reticulum stress markers, including protein levels of phosphorylated-protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated-IRE1α, phosphorylated-eIF2α, C/EBP homologous protein, and binding immunoglobulin protein; endoplasmic reticulum chaperone gene expression; and XBP1 messenger RNA splicing, as well as increased cleaved caspase 3 and 8 in embryonic hearts. Furthermore, maternal type 2 diabetes mellitus triggered excessive apoptosis in ventricular myocardium, endocardial cushion, and outflow tract of the embryonic heart. Similar to those observations in type 1 diabetic embryopathy, maternal type 2 diabetes mellitus causes heart defects in the developing embryo manifested with oxidative stress, endoplasmic reticulum stress, and excessive apoptosis in heart cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Antioxidant activity and induction of mechanisms of resistance to stresses related to the inoculation with Azospirillum brasilense.

PubMed

Fukami, Josiane; Ollero, Francisco Javier; de la Osa, Clara; Valderrama-Fernández, Rocio; Nogueira, Marco Antonio; Megías, Manuel; Hungria, Mariangela

2018-06-07

We investigated the effects of Azospirillum brasilense strains Ab-V5 and Ab-V6 in the induction of mechanisms of systemic acquired resistance (SAR) and induced system resistance (ISR) on maize (Zea mays L.) plants. Under normal growth conditions, the treatments consisted of the standard inoculation of cells at sowing, and leaf spray of cells or their metabolites at the V2.5 growth stage; under saline stress (170 mM NaCl), the treatment consisted of standard single and co-inoculation of A. brasilense and Rhizobium tropici. The main compounds in the Azospirillum metabolites were identified as indole-3-acetic acid (IAA) and salicylic acid (SA). Under normal conditions, A. brasilense cells applied at sowing or by leaf spray increased the activities of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) in leaves, and of ascorbate peroxidase (APX) in roots; however, interestingly, in general the highest activities were observed by leaf spray of metabolites. Under normal conditions, the highest levels of salicylic acid (SA) and jasmonic acid (JA) were achieved in leaves by leaf spray of metabolites, of SA in roots by leaf spray of cells, and of JA in roots by standard inoculation and leaf spray of metabolites. Under saline stress, plant protection occurred via SA and abscisic acid (ABA), but not JA. In general, inoculation resulted in further increases in SA in leaves and roots, and ABA in leaves. We hypothesize that A. brasilense confers protection to maize plants by simultaneous induction of JA and SA pathways, and, under saline stressing conditions, by SA and ABA pathways.

Regulation of eIF2α phosphorylation in hindlimb-unloaded and STS-135 space-flown mice

NASA Astrophysics Data System (ADS)

Zhao, Liming; Tanjung, Nancy; Swarnkar, Gaurav; Ledet, Eric; Yokota, Hiroki

2012-09-01

Various environmental stresses elevate the phosphorylation level of eukaryotic translation initiation factor 2 alpha (eIF2α) and induce transcriptional activation of a set of stress responsive genes such as activating transcription factors 3 and 6 (ATF3 and ATF6), CCAAT/enhancer-binding protein homologous protein (CHOP), and Xbp1 (X-box binding protein 1). These stress sources include radiation, oxidation, and stress to the endoplasmic reticulum, and it is recently reported that unloading by hindlimb unloading is such a stress source. No studies, however, have examined the phosphorylation level of eIF2α (eIF2α-p) using skeletal samples that have experienced microgravity in space. In this study we addressed a question: Does a mouse tibia flown in space show altered levels of eIF2α-p? To address this question, we obtained STS-135 flown samples that were harvested 4-7 h after landing. The tibia and femur isolated from hindlimb unloaded mice were employed as non-flight controls. The effects of loading were also investigated in non- flight controls. Results indicate that the level of eIF2α-p of the non-flight controls was elevated during hindlimb unloading and reduced after being released from unloading. Second, the eIF2α-p level of space-flown samples was decreased, and mechanical loading to the tibia caused the reduction of the eIF2α-p level. Third, the mRNA levels of ATF3, ATF6, and CHOP were lowered in space-flown samples as well as in the non-flight samples 4-7 h after being released from unloading. Collectively, the results herein indicated that a release from hindlimb unloading and a return to normal weight environment from space provided a suppressive effect to eIF2α-linked stress responses and that a period of 2-4 h is sufficient to induce this suppressive outcome.

Ursolic acid protects monocytes against metabolic stress-induced priming and dysfunction by preventing the induction of Nox4☆

PubMed Central

Ullevig, Sarah L.; Kim, Hong Seok; Nguyen, Huynh Nga; Hambright, William S.; Robles, Andrew J.; Tavakoli, Sina; Asmis, Reto

2014-01-01

Aims Dietary supplementation with ursolic acid (UA) prevents monocyte dysfunction in diabetic mice and protects mice against atherosclerosis and loss of renal function. The goal of this study was to determine the molecular mechanism by which UA prevents monocyte dysfunction induced by metabolic stress. Methods and results Metabolic stress sensitizes or “primes” human THP-1 monocytes and murine peritoneal macrophages to the chemoattractant MCP-1, converting these cells into a hyper-chemotactic phenotype. UA protected THP-1 monocytes and peritoneal macrophages against metabolic priming and prevented their hyper-reactivity to MCP-1. UA blocked the metabolic stress-induced increase in global protein-S-glutathionylation, a measure of cellular thiol oxidative stress, and normalized actin-S-glutathionylation. UA also restored MAPK phosphatase-1 (MKP1) protein expression and phosphatase activity, decreased by metabolic priming, and normalized p38 MAPK activation. Neither metabolic stress nor UA supplementation altered mRNA or protein levels of glutaredoxin-1, the principal enzyme responsible for the reduction of mixed disulfides between glutathione and protein thiols in these cells. However, the induction of Nox4 by metabolic stress, required for metabolic priming, was inhibited by UA in both THP-1 monocytes and peritoneal macrophages. Conclusion UA protects THP-1 monocytes against dysfunction by suppressing metabolic stress-induced Nox4 expression, thereby preventing the Nox4-dependent dysregulation of redox-sensitive processes, including actin turnover and MAPK-signaling, two key processes that control monocyte migration and adhesion. This study provides a novel mechanism for the anti-inflammatory and athero- and renoprotective properties of UA and suggests that dysfunctional blood monocytes may be primary targets of UA and related compounds. PMID:24494201

Chronic stress and coping among cardiac surgeons: a single center study

PubMed Central

Spiliopoulos, Kyriakos; Gansera, Laura; Weiland, Hans Christian; Schuster, Tibor; Eichinger, Walter; Gansera, Brigitte

2014-01-01

Introduction Cardiac surgeons stress may impair their quality of life and professional practice. Objective To assess perceived chronic stress and coping strategies among cardiac surgeons. Methods Twenty-two cardiac surgeons answered two self-assessment questionnaires, the Trier Inventory for Chronic Stress and the German SGV for coping strategies. Results Participants mean age was 40±14.1 years and 13 were male; eight were senior physicians and 14 were residents. Mean values for the Trier Inventory for Chronic Stress were within the normal range. Unexperienced physicians had significantly higher levels of dissatisfaction at work, lack of social recognition, and isolation (P<0.05). Coping strategies such as play down, distraction from situation, and substitutional satisfaction were also significantly more frequent among unexperienced surgeons. "Negative" stress-coping strategies occur more often in experienced than in younger colleagues (P=0.029). Female surgeons felt more exposed to overwork (P=0.04) and social stress (P=0.03). Conclusion Cardiac surgeons show a tendency to high perception of chronic stress phenomena and vulnerability for negative coping strategies. PMID:25372902

Fatigue and mental health in Australian rural and regional ambulance personnel.

PubMed

Pyper, Zoe; Paterson, Jessica L

2016-02-01

Australian ambulance personnel experience stress, fatigue and exposure to traumatic events. These risks have been extensively researched in metropolitan paramedics. However, there has been limited research in rural and regional personnel. Rural and regional ambulance personnel make up a significant proportion of the Australian ambulance workforce and may be exposed to unique stressors. The aim of the current study was to investigate levels of fatigue, stress, and emotional trauma in rural and regional ambulance personnel. A sample of 134 (103 male, 31 female) rural and regional ambulance personnel completed a mixed methods survey assessing fatigue, stress and emotional trauma. Data were analysed using a combination of descriptive analysis and qualitative, deductive analysis that involved data immersion, coding, and categorisation. Participants reported high levels of fatigue and emotional trauma. Qualitative data revealed stressors including community expectations and 'office politics'. Participants also reported negative effects of fatigue including errors in drug administration and falling asleep while driving. The majority of participants reported normal levels of stress. It may be the case that working with known individuals in a community offers some degree of 'protective' impact for stress in rural and regional ambulance personnel. This is one of the first studies to investigate fatigue, stress, and emotional trauma in a rural and regional ambulance population. Results indicate a complex and unique profile of risks and challenges for this critical and understudied community resource. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Religious and spiritual beliefs, self-esteem, anxiety, and depression among nursing students.

PubMed

Papazisis, Georgios; Nicolaou, Panagiotis; Tsiga, Evangelia; Christoforou, Theodora; Sapountzi-Krepia, Despina

2014-06-01

Research of the role of religious belief and/or spirituality has been conducted on a wide range of health-related topics, across many disciplines, and in many countries. The purpose of this study was to determine the relationship between religious beliefs, self-esteem, anxiety, and depression in nursing students in Cyprus. One hundred and twenty-three nursing students were asked to complete a survey consisting of four self-report questionnaires (Beck Depression Inventory, State-Trait Anxiety Inventory, The Royal Free Interview for Religious and Spiritual Beliefs, and Rosenberg Self-esteem Scale). The lowest levels of depression were observed in the third and fourth study year. Normal self-esteem levels were found in the majority of the students (71.3%) and most of them perceived current stress at mild levels. No significant differences on the basis of sex were observed. The vast majority (98.2%) of the students stated a strong religious and/or a spiritual belief that was strongly positively correlated with increased self-esteem and negatively correlated with depression, current stress, and stress as personality trait. © 2013 Wiley Publishing Asia Pty Ltd.

Placental Induced Growth Factor (PIGf) in Coronary Artery Disease

NASA Technical Reports Server (NTRS)

Sundaresan, Alamelu; Carabello, Blaise; Mehta, Satish; Schlegel, Todd; Pellis, Neal; Ott, Mark; Pierson, Duane

2010-01-01

Our previous studies on normal human lymphocytes have shown a five-fold increase (p less than 0.001) in angiogenic inducers such as Placental Induced Growth Factor (PIGf) in physiologically stressful environments such as modeled microgravity, a space analog. This suggests de-regulation of cardiovascular signalling pathways indicated by upregulation of PIGf. In the current study, we measured PIGf in the plasma of 33 patients with and without coronary artery disease (CAD) to investigate whether such disease is associated with increased levels of PIGf. A control consisting of 31 sex matched apparently healthy subjects was also included in the study. We observed that the levels of PIGf in CAD patients were significantly increased compared to those in healthy control subjects (p less than 0.001) and usually increased beyond the clinical threshold level (greater than 27ng/L). The mechanisms leading to up-regulation of angiogenic factors and the adaptation of organisms to stressful environments such as isolation, high altitude, hypoxia, ischemia, microgravity, increased radiation, etc are presently unknown and require further investigation in spaceflight and these other physiologically stressed environments.

Gravitational failure of sea cliffs in weakly lithified sediment

USGS Publications Warehouse

Hampton, M.A.

2002-01-01

Gravitational failure of sea cliffs eroded into weakly lithified sediment at several sites in California involves episodic stress-release fracturing and cantilevered block falls. The principal variables that influence the gravitational stability are tensional stresses generated during the release of horizontal confining stress and weakening of the sediment with increased saturation levels. Individual failures typically comprise less than a cubic meter of sediment, but large areas of a cliff face can be affected by sustained instability over a period of several days. Typically, only the outer meter or so of sediment is removed during a failure episode. In-place sediment saturation levels vary over time and space, generally being higher during the rainy season but moderate to high year-round. Laboratory direct-shear tests show that sediment cohesion decreases abruptly with increasing saturation level; the decrease is similar for all tested sediment if the cohesion is normalized by the maximum, dry-sediment cohesion. Large failures that extend over most or all of the height of the sea cliff are uncommon, but a few large wedge-shaped failures sometimes occur, as does separation of large blocks at sea cliff-gully intersections.

Abiotic Stress Tolerance in Plants: Myriad Roles of Ascorbate Peroxidase

PubMed Central

Pandey, Saurabh; Fartyal, Dhirendra; Agarwal, Aakrati; Shukla, Tushita; James, Donald; Kaul, Tanushri; Negi, Yogesh K.; Arora, Sandeep; Reddy, Malireddy K.

2017-01-01

One of the most significant manifestations of environmental stress in plants is the increased production of Reactive Oxygen Species (ROS). These ROS, if allowed to accumulate unchecked, can lead to cellular toxicity. A battery of antioxidant molecules is present in plants for keeping ROS levels under check and to maintain the cellular homeostasis under stress. Ascorbate peroxidase (APX) is a key antioxidant enzyme of such scavenging systems. It catalyses the conversion of H2O2 into H2O, employing ascorbate as an electron donor. The expression of APX is differentially regulated in response to environmental stresses and during normal plant growth and development as well. Different isoforms of APX show differential response to environmental stresses, depending upon their sub-cellular localization, and the presence of specific regulatory elements in the upstream regions of the respective genes. The present review delineates role of APX isoforms with respect to different types of abiotic stresses and its importance as a key antioxidant enzyme in maintaining cellular homeostasis. PMID:28473838

The NADPH-oxidase AtRbohI plays a positive role in drought-stress response in Arabidopsis thaliana

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Huan; Yan, Jingwei; Yu, Xiaoyun

As the major resource of reactive oxygen species (ROS), the NADPH oxidases (Rbohs) have been shown to play important roles in plant cells under normal growth and stress conditions. Although many family members of Rbohs were studied, little is known about the function of RbohI in Arabidopsis thaliana. Here, we report that exogenous ABA application decreases RbohI expression and mannitol significantly increases RbohI expression at transcript level. The RbohI transcripts were strongly detected in dry seeds and roots. The loss-of-function mutant rbohI exhibited sensitivity to ABA and mannitol stress during germination. Furthermore, the lateral root growth of rbohI was severelymore » inhibited after treatment with mannitol stress. Overexpression of RbohI in Arabidopsis significantly improves the drought tolerance. Moreover, more H 2O 2 accumulated in RbohI overexpressors than in wild type plants in response to mannitol stress. Our conclusion is that AtRbohI functions in drought-stress response in Arabidopsis thaliana.« less

Family functioning, parenting stress and quality of life in mothers and fathers of Polish children with high functioning autism or Asperger syndrome

PubMed Central

2017-01-01

The aim of the study was to investigate the perception of the family functioning in parents of children with autism spectrum disorders (ASD) with normal-range intelligence and the relationships between family functioning, parenting stress and quality of life. Dyads of parents of children with ASD without intellectual disability and parents of typically developing children (controls) completed a set of self-report questionnaires. Parents of children with ASD reported lower functioning of the family as a whole and their own functioning as family members; they exhibited higher levels of parenting stress and lower quality of life. Mothers of children with ASD experienced more stress in personal domain than fathers. Relationships between family functioning, parenting stress and quality of life have been established. There were also moderate to strong correlations in mother-father dyads between their assessments of family functioning, parenting stress and QoL in social relationships and environmental domains. PMID:29036188

Family functioning, parenting stress and quality of life in mothers and fathers of Polish children with high functioning autism or Asperger syndrome.

PubMed

Pisula, Ewa; Porębowicz-Dörsmann, Anna

2017-01-01

The aim of the study was to investigate the perception of the family functioning in parents of children with autism spectrum disorders (ASD) with normal-range intelligence and the relationships between family functioning, parenting stress and quality of life. Dyads of parents of children with ASD without intellectual disability and parents of typically developing children (controls) completed a set of self-report questionnaires. Parents of children with ASD reported lower functioning of the family as a whole and their own functioning as family members; they exhibited higher levels of parenting stress and lower quality of life. Mothers of children with ASD experienced more stress in personal domain than fathers. Relationships between family functioning, parenting stress and quality of life have been established. There were also moderate to strong correlations in mother-father dyads between their assessments of family functioning, parenting stress and QoL in social relationships and environmental domains.

Coseismic and postseismic stress changes in a subducting plate: Possible stress interactions between large interplate thrust and intraplate normal-faulting earthquakes

NASA Astrophysics Data System (ADS)

Mikumo, Takeshi; Yagi, Yuji; Singh, Shri Krishna; Santoyo, Miguel A.

2002-01-01

A large intraplate, normal-faulting earthquake (Mw = 7.5) occurred in 1999 in the subducting Cocos plate below the downdip edge of the ruptured thrust fault of the 1978 Oaxaca, Mexico, earthquake (Mw = 7.8). This situation is similar to the previous case of the 1997 normal-faulting event (Mw = 7.1) that occurred beneath the rupture area of the 1985 Michoacan, Mexico, earthquake (Mw = 8.1). We investigate the possibility of any stress interactions between the preceding 1978 thrust and the following 1999 normal-faulting earthquakes. For this purpose, we estimate the temporal change of the stress state in the subducting Cocos plate by calculating the slip distribution during the 1978 earthquake through teleseismic waveform inversion, the dynamic rupture process, and the resultant coseismic stress change, together with the postseismic stress variations due to plate convergence and the viscoelastic relaxation process. To do this, we calculate the coseismic and postseismic changes of all stress components in a three-dimensional space, incorporating the subducting slab, the overlying crust and uppermost mantle, and the asthenosphere. For the coseismic stress change we solve elastodynamic equations, incorporating the kinematic fault slip as an observational constraint under appropriate boundary conditions. To estimate postseismic stress accumulations due to plate convergence, a virtual backward slip is imposed to lock the main thrust zone. The effects of viscoelastic stress relaxations of the coseismic change and the back slip are also included. The maximum coseismic increase in the shear stress and the Coulomb failure stress below the downdip edge of the 1978 thrust fault is estimated to be in the range between 0.5 and 1.5 MPa, and the 1999 normal-faulting earthquake was found to take place in this zone of stress increase. The postseismic variations during the 21 years after the 1978 event modify the magnitude and patterns of the coseismic stress change to some extent but are not large enough to overcome the coseismic change. These results suggest that the coseismic stress increase due to the 1978 thrust earthquake may have enhanced the chance of occurrence of the 1999 normal-faulting event in the subducting plate. If this is the case, one of the possible mechanisms could be static fatigue of rock materials around preexisting weak planes involved in the subducting plate, and it is speculated that that one of these planes might have been reactivated and fractured because of stress corrosion cracking under the applied stress there for 21 years.

Electrical and mechanical characteristics of fully transparent IZO thin-film transistors on stress-relieving bendable substrates

NASA Astrophysics Data System (ADS)

Park, Sukhyung; Cho, Kyoungah; Oh, Hyungon; Kim, Sangsig

2016-10-01

In this study, we report the electrical and mechanical characteristics of fully transparent indium zinc oxide (IZO) thin-film transistors (TFTs) fabricated on stress-relieving bendable substrates. An IZO TFT on a stress-relieving substrate can operate normally at a bending radius of 6 mm, while an IZO TFT on a normal plastic substrate fails to operate normally at a bending radius of 15 mm. A plastic island with high Young's modulus embedded on a soft elastomer layer with low Young's modulus plays the role of a stress-relieving substrate for the operation of the bent IZO TFT. The stress and strain distributions over the IZO TFT will be analyzed in detail in this paper.

Design and Analysis of the Warm-To Suspension Links for Jefferson Lab's 11 Gev/c Super High Momentum Spectrometer

NASA Astrophysics Data System (ADS)

Sun, E.; Brindza, P.; Lassiter, S.; Fowler, M.

2010-04-01

This paper describes design and analysis performed for the warm-to-cold suspension links of the warm iron yoke superconducting quadrupole magnets, and superconducting dipole magnet. The results of investigation of titanium Ti-6Al-4V and Nitronic 50 stainless steel for the suspension links to support the cold mass, preloads, forces due to cryogenic temperature, and imbalanced magnetic forces from misalignments are presented. Allowable stresses at normal-case scenarios and worst-case scenarios, space constraints, and heat leak considerations are discussed. Principles of the ASME Pressure Vessel Code were used to determine allowable stresses. Optimal angles of the suspension links were obtained by calculation and finite element methods. The stress levels of suspension links at multiple scenarios are presented, discussed, and compared with the allowable stresses.

Hsp27 (HSPB1) differential expression in normal salivary glands and pleomorphic adenomas and association with an increased Bcl2/Bax ratio.

PubMed

Siqueira, Elisa C de; Souza, Fabrício T A; Diniz, Marina G; Gomez, Ricardo S; Gomes, Carolina C

2015-01-01

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm. The Hsp27 (HSPB1) is an antiapoptotic protein whose synthesis follows cytotoxic stresses and result in a transient increase in tolerance to subsequent cell injury. Although Hsp27 is expressed in a range of normal tissues and neoplasms, a wide variation in its expression exists among different cells and tissues types. In certain tumours of glandular origin (such as oesophageal adenocarcinomas), the level of Hsp27 is decreased. In the present study, Hsp27 protein levels were evaluated by enzyme-linked immunosorbent assay (ELISA) in a set of 18 fresh PA and 12 normal salivary gland samples. In addition, we tested if Hsp27 protein levels correlated with p53 expression and cell proliferation index, as well as with the transcriptional levels of Bcl-2-associated X protein (BAX), B cell lymphoma 2 (BCL2) and Caspase 3 in PA. We further tested the association between Hsp27 expression and PA tumour size. While all normal salivary gland samples expressed Hsp27 protein, only half of the PA samples expressed it, resulting in a reduced expression of Hsp27 in PA when compared with normal salivary glands (P = 0.003). The expression levels of this protein correlated positively with a higher messenger ribonucleic acid (mRNA) ratio of Bcl2/Bax (R = 0.631; P = 0.01). In conclusion, a decreased Hsp27 protein expression level in PA was found. In addition, Hsp27 levels correlated positively with the Bcl2/Bax mRNA ratio, suggesting an antiapoptotic effect.

A randomized trial on mineralocorticoid receptor blockade in men: effects on stress responses, selective attention, and memory.

PubMed

Cornelisse, Sandra; Joëls, Marian; Smeets, Tom

2011-12-01

Corticosteroids, released in high amounts after stress, exert their effects via two different receptors in the brain: glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs). GRs have a role in normalizing stress-induced effects and promoting consolidation, while MRs are thought to be important in determining the threshold for activation of the hypothalamic-pituitary-adrenal (HPA) axis. We investigated the effects of MR blockade on HPA axis responses to stress and stress-induced changes in cognitive function. In a double-blind, placebo-controlled study, 64 healthy young men received 400 mg of the MR antagonist spironolactone or placebo. After 1.5 h, they were exposed to either a Trier Social Stress Test or a non-stressful control task. Responses to stress were evaluated by hormonal, subjective, and physiological measurements. Afterwards, selective attention, working memory, and long-term memory performance were assessed. Spironolactone increased basal salivary cortisol levels as well as cortisol levels in response to stress. Furthermore, spironolactone significantly impaired selective attention, but only in the control group. The stress group receiving spironolactone showed impaired working memory performance. By contrast, long-term memory was enhanced in this group. These data support a role of MRs in the regulation of the HPA axis under basal conditions as well as in response to stress. The increased availability of cortisol after spironolactone treatment implies enhanced GR activation, which, in combination with MR blockade, presumably resulted in a decreased MR/GR activation ratio. This condition influences both selective attention and performance in various memory tasks.

Differential hippocampal protein expression between normal aged rats and aged rats with postoperative cognitive dysfunction: A proteomic analysis.

PubMed

Li, Yang; Wang, Saiying; Ran, Ke; Hu, Zhonghua; Liu, Zhaoqian; Duan, Kaiming

2015-08-01

The aim of the present study was to investigate the differences in the expression of hippocampal proteins between normal control aged rats and aged rats with postoperative cognitive dysfunction (POCD). A total of 24 aged rats were randomly divided into a surgery group (n=12) and a control group (n=12). The rats in the surgery group were treated with 2 h isoflurane anesthesia and splenectomy, while the rats in the control group received 40% oxygen for 2 h without surgery. The cognitive functions of the two groups were examined using a Y-maze test. The protein expression profiles of the hippocampus of six aged rats (three rats with POCD and three from the normal control group) were assessed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry. A total of three differential proteins were further confirmed between the POCD rats and normal rats using reverse transcription quantitative polymerase chain reaction (RT-qPCR). The expression levels of 21 proteins in the rats with POCD were significantly different compared with the normal control rats. These proteins were functionally clustered to synaptic plasticity (three proteins), oxidative stress (four proteins), energy production (six proteins), neuroinflammation (three proteins) and glutamate metabolism (two proteins). In addition, three proteins (fatty acid binding protein 7, brain, glutamate dehydrogenase 1 and glutamine synthetase), associated with astrocytic function, were significantly different in the rats with POCD compared with those in the normal control (P<0.05). Similar changes in the mRNA expression levels of the three proteins in the hippocampi of POCD rats were also detected using RT-qPCR. Neuroinflammation, glutamate toxicity and oxidative stress were possibly involved in the pathological mechanism underlying POCD in aged rats. In addition, astrocytes may also be important in POCD in aged rats.

Quercetin Attenuates Vascular Calcification through Suppressed Oxidative Stress in Adenine-Induced Chronic Renal Failure Rats.

PubMed

Chang, Xue-Ying; Cui, Lei; Wang, Xing-Zhi; Zhang, Lei; Zhu, Dan; Zhou, Xiao-Rong; Hao, Li-Rong

2017-01-01

This study investigated whether quercetin could alleviate vascular calcification in experimental chronic renal failure rats induced by adenine. 32 adult male Wistar rats were randomly divided into 4 groups fed normal diet, normal diet with quercetin supplementation (25 mg/kg·BW/d), 0.75% adenine diet, or adenine diet with quercetin supplementation. All rats were sacrificed after 6 weeks of intervention. Serum renal functions biomarkers and oxidative stress biomarkers were measured and status of vascular calcification in aorta was assessed. Furthermore, the induced nitric oxide synthase (iNOS)/p38 mitogen activated protein kinase (p38MAPK) pathway was determined to explore the potential mechanism. Adenine successfully induced renal failure and vascular calcification in rat model. Quercetin supplementation reversed unfavorable changes of phosphorous, uric acid (UA) and creatinine levels, malonaldehyde (MDA) content, and superoxide dismutase (SOD) activity in serum and the increases of calcium and alkaline phosphatase (ALP) activity in the aorta ( P < 0.05) and attenuated calcification and calcium accumulation in the medial layer of vasculature in histopathology. Western blot analysis showed that iNOS/p38MAPK pathway was normalized by the quercetin supplementation. Quercetin exerted a protective effect on vascular calcification in adenine-induced chronic renal failure rats, possibly through the modulation of oxidative stress and iNOs/p38MAPK pathway.

Quercetin Attenuates Vascular Calcification through Suppressed Oxidative Stress in Adenine-Induced Chronic Renal Failure Rats

PubMed Central

Chang, Xue-ying; Cui, Lei; Wang, Xing-zhi; Zhang, Lei; Zhu, Dan

2017-01-01

Background This study investigated whether quercetin could alleviate vascular calcification in experimental chronic renal failure rats induced by adenine. Methods 32 adult male Wistar rats were randomly divided into 4 groups fed normal diet, normal diet with quercetin supplementation (25 mg/kg·BW/d), 0.75% adenine diet, or adenine diet with quercetin supplementation. All rats were sacrificed after 6 weeks of intervention. Serum renal functions biomarkers and oxidative stress biomarkers were measured and status of vascular calcification in aorta was assessed. Furthermore, the induced nitric oxide synthase (iNOS)/p38 mitogen activated protein kinase (p38MAPK) pathway was determined to explore the potential mechanism. Results Adenine successfully induced renal failure and vascular calcification in rat model. Quercetin supplementation reversed unfavorable changes of phosphorous, uric acid (UA) and creatinine levels, malonaldehyde (MDA) content, and superoxide dismutase (SOD) activity in serum and the increases of calcium and alkaline phosphatase (ALP) activity in the aorta (P < 0.05) and attenuated calcification and calcium accumulation in the medial layer of vasculature in histopathology. Western blot analysis showed that iNOS/p38MAPK pathway was normalized by the quercetin supplementation. Conclusions Quercetin exerted a protective effect on vascular calcification in adenine-induced chronic renal failure rats, possibly through the modulation of oxidative stress and iNOs/p38MAPK pathway. PMID:28691026

The effects of dietary fish oil on inflammation, fibrosis and oxidative stress associated with obstructive renal injury in rats.

PubMed

Peake, Jonathan M; Gobe, Glenda C; Fassett, Robert G; Coombes, Jeff S

2011-03-01

We examined whether dietary supplementation with fish oil modulates inflammation, fibrosis and oxidative stress following obstructive renal injury. Three groups of Sprague-Dawley rats (n=16 per group) were fed for 4 wk on normal rat chow (oleic acid), chow containing fish oil (33 g eicosapentaenoic acid and 26 g docosahexaenoic acid per kg diet), or chow containing safflower oil (60 g linoleic acid per kg diet). All diets contained 7% fat. After 4 wk, the rats were further subdivided into four smaller groups (n=4 per group). Unilateral ureteral obstruction was induced in three groups (for 4, 7 and 14 days). The fourth group for each diet did not undergo surgery, and was sacrificed as controls at 14 days. When rats were sacrificed, plasma and portions of the kidneys were removed and frozen; other portions of kidney tissue were fixed and prepared for histology. Compared with normal chow and safflower oil, fish oil attenuated collagen deposition, macrophage infiltration, TGF-β expression, apoptosis, and tissue levels of arachidonic acid, MIP-1α, IL-1β, MCP-1 and leukotriene B(4). Compared with normal chow, fish oil increased the expression of HO-1 protein in kidney tissue. Fish oil intake reduced inflammation, fibrosis and oxidative stress following obstructive renal injury. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Melanoma Inhibition by Anthocyanins Is Associated with the Reduction of Oxidative Stress Biomarkers and Changes in Mitochondrial Membrane Potential.

PubMed

Diaconeasa, Zoriţa; Ayvaz, Huseyin; Ruginǎ, Dumitriţa; Leopold, Loredana; Stǎnilǎ, Andreea; Socaciu, Carmen; Tăbăran, Flaviu; Luput, Lavinia; Mada, Diana Carla; Pintea, Adela; Jefferson, Andrew

2017-12-01

Anthocyanins are water soluble pigments which have been proved to exhibit health benefits. Several studies have investigated their effects on several types of cancer, but little attention has been given to melanoma. The phytochemical content of nine different berry samples was assessed by liquid chromatography followed by electrospray ionization mass spectrometry (LC-ESI + -MS). Twenty-six anthocyanins were identified, after a previous C 18 Sep-pak clean-up procedure. Chokeberry and red grape anthocyanins rich extracts (C-ARE and RG-ARE) were selected to be tested on normal and melanoma cell lines, due to their different chemical pattern. C-ARE composition consists of cyanidin aglycone glycosylated with different sugars; while RG-ARE contains glucosylated derivatives of five different aglycones. Both C-ARE and RG-ARE anthocyanins reduced proliferation, increased oxidative stress biomarkers and diminished mitochondrial membrane potential in melanoma cells, having no negative influence on normal cells. A synergistic response may be attributed to the five different aglycones present in RG-ARE, which proved to exert greater effects on melanoma cells than the mixture of cyanidin derivatives with different sugars (C-ARE). In conclusion, C-ARE and RG-ARE anthocyanins may inhibit melanoma cell proliferation and increase the level of oxidative stress, with opposite effect on normal cells. Therefore, anthocyanins might be recommended as active ingredients for cosmetic and nutraceutical industry. Graphical Abstract ᅟ.

Selection of Suitable Reference Genes for RT-qPCR Normalization under Abiotic Stresses and Hormone Stimulation in Persimmon (Diospyros kaki Thunb)

PubMed Central

Wang, Peihong; Xiong, Aisheng; Gao, Zhihong; Yu, Xinyi; Li, Man; Hou, Yingjun; Sun, Chao; Qu, Shenchun

2016-01-01

The success of quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) to quantify gene expression depends on the stability of the reference genes used for data normalization. To date, systematic screening for reference genes in persimmon (Diospyros kaki Thunb) has never been reported. In this study, 13 candidate reference genes were cloned from 'Nantongxiaofangshi' using information available in the transcriptome database. Their expression stability was assessed by geNorm and NormFinder algorithms under abiotic stress and hormone stimulation. Our results showed that the most suitable reference genes across all samples were UBC and GAPDH, and not the commonly used persimmon reference gene ACT. In addition, UBC combined with RPII or TUA were found to be appropriate for the "abiotic stress" group and α-TUB combined with PP2A were found to be appropriate for the "hormone stimuli" group. For further validation, the transcript level of the DkDREB2C homologue under heat stress was studied with the selected genes (CYP, GAPDH, TUA, UBC, α-TUB, and EF1-α). The results suggested that it is necessary to choose appropriate reference genes according to the test materials or experimental conditions. Our study will be useful for future studies on gene expression in persimmon. PMID:27513755

REST and stress resistance in ageing and Alzheimer's disease

NASA Astrophysics Data System (ADS)

Lu, Tao; Aron, Liviu; Zullo, Joseph; Pan, Ying; Kim, Haeyoung; Chen, Yiwen; Yang, Tun-Hsiang; Kim, Hyun-Min; Drake, Derek; Liu, X. Shirley; Bennett, David A.; Colaiácovo, Monica P.; Yankner, Bruce A.

2014-03-01

Human neurons are functional over an entire lifetime, yet the mechanisms that preserve function and protect against neurodegeneration during ageing are unknown. Here we show that induction of the repressor element 1-silencing transcription factor (REST; also known as neuron-restrictive silencer factor, NRSF) is a universal feature of normal ageing in human cortical and hippocampal neurons. REST is lost, however, in mild cognitive impairment and Alzheimer's disease. Chromatin immunoprecipitation with deep sequencing and expression analysis show that REST represses genes that promote cell death and Alzheimer's disease pathology, and induces the expression of stress response genes. Moreover, REST potently protects neurons from oxidative stress and amyloid β-protein toxicity, and conditional deletion of REST in the mouse brain leads to age-related neurodegeneration. A functional orthologue of REST, Caenorhabditis elegans SPR-4, also protects against oxidative stress and amyloid β-protein toxicity. During normal ageing, REST is induced in part by cell non-autonomous Wnt signalling. However, in Alzheimer's disease, frontotemporal dementia and dementia with Lewy bodies, REST is lost from the nucleus and appears in autophagosomes together with pathological misfolded proteins. Finally, REST levels during ageing are closely correlated with cognitive preservation and longevity. Thus, the activation state of REST may distinguish neuroprotection from neurodegeneration in the ageing brain.

Airplane Stress Analysis

NASA Technical Reports Server (NTRS)

Zahm, A F; Crook, L H

1918-01-01

Report presents stress analysis of individual components of an airplane. Normal and abnormal loads, sudden loads, simple stresses, indirect simple stresses, resultant unit stress, repetitive and equivalent stress, maximum steady load and stress are considered.

Serum antioxidant status in patients with systemic sclerosis.

PubMed

Hassan, Iffat; Sajad, Peerzada; Majid, Sabiya; Hassan, Tehseen

2013-05-01

Vascular endothelial dysfunction is a central event in pathogenesis of a variety of human diseases. Systemic sclerosis is one of such diseases. The oxidative stress and depletion of antioxidants in the serum is believed to be one of the factors in causing this dysfunction. The aim of this case control study was to compare the levels of antioxidants in the serum of patients with systemic sclerosis and the normal age and sex matched controls. Our study consisted of 16 successively admitted patients with systemic sclerosis and 16 healthy, age and sex matched controls. The age group of patient's ranged between 25 and 55 years. The duration of the disease in patients ranged from 1 to 8 years. The serum of patients and controls were assayed for the levels of antioxidants (GSH, NO, MDA, SOD and GPX) by spectrophotometry. The statistical method of analysis used was the one sample t-test. THE MEDIAN LEVELS OF ANTIOXIDANTS IN THE CONTROL PATIENTS WERE: SOD-4.14 units/ml; GSH-4.76 units/ml; NO-5.58 nmol/l; MDA-0.53 nmol/l and GPX-49 μmol/l. The levels of NO, GSH and SOD were decreased in these patients with a significant P value (<0.001) whereas the levels of GPX and MDA were normal to increased with a significant P value. The depletion of antioxidants and oxidative stress in serum might be responsible for the vascular dysfunction and other hallmark manifestations of systemic sclerosis. Therefore micronutrient antioxidant supplements may be of therapeutic value.

Impact of composite plates: Analysis of stresses and forces

NASA Technical Reports Server (NTRS)

Moon, F. C.; Kim, B. S.; Fang-Landau, S. R.

1976-01-01

The foreign object damage resistance of composite fan blades was studied. Edge impact stresses in an anisotropic plate were first calculated incorporating a constrained layer damping model. It is shown that a very thin damping layer can dramatically decrease the maximum normal impact stresses. A multilayer model of a composite plate is then presented which allows computation of the interlaminar normal and shear stresses. Results are presented for the stresses due to a line impact load normal to the plane of a composite plate. It is shown that significant interlaminar tensile stresses can develop during impact. A computer code was developed for this problem using the fast Fourier transform. A marker and cell computer code were also used to investigate the hydrodynamic impact of a fluid slug against a wall or turbine blade. Application of fluid modeling of bird impact is reviewed.

Quantitation of mRNAs for α 1-acid glycoprotein and for serum albumin in livers of normal, stressed, fasted, and refed rats. [ 125I or 131I radioimmunoassay for protein products of specific mRNA activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Linda Jean

1978-01-01

A new procedure for determining the relative levels of a specific mRNA species was developed and applied to mRNA for rat serum albumin (RSA) and α 1-AGP) in rat liver. The method is a radioimmunoassay ( 125In or 131I) for the completed protein, but which also detects antigenic determinants in nascent polypeptide chains on plysomes synthesizing the specific protein. Results show that 24 hs after stressing the rat by turpentine injection the total number of polysomes per mg DNA has increased by 20 to 25%; however, the number of RSA synthesizing polysomes per mg DNA has decreased slightly. In ratsmore » fasted for 6 days, the number of RSA synthesizing polysomes per mg polysomal RNA is only slightly below normal, but the total number of RSA synthesizing polysomes per mg DNA has decreased by 40%. Again, it is seen that RSA mRNA levels do not decrease as sharply as the rate of RSA synthesis. Twelve hours after refeeding the rats, the number of RSA synthesizing polysomes begins to increase, reaching a peak two to three times normal levels 24 to 48 hours after commencement of refeeding. During the first 24 hs after turpentine injection, there is a linear increase in the number of α 1-AGP synthesizing polysomes. The increase is smaller during the next 24 hs and there is a small decrease between 48 and 72 hs. The serum concentrations of α 1-AGP following turpentine treatment reflect these changes in polysome levels. It was not possible to compare the number of α 1-AGP synthesizing polysomes in livers of normal, fasted, and refed rats because the levels detected were only slightly higher than those seen in rat and rat kidney polysome controls. This background activity must be eliminated before the technique can be applied to quantitating mRNA for proteins synthesized in very small quantities. This technique offers several advantages over other procedures commonly used to quantitate mRNA. (ERB)« less

Studies on toxicity, anti-stress and hepato-protective properties of Kombucha tea.

PubMed

Pauline, T; Dipti, P; Anju, B; Kavimani, S; Sharma, S K; Kain, A K; Sarada, S K; Sairam, M; Ilavazhagan, G; Devendra, K; Selvamurthy, W

2001-09-01

The objective of the study was to evaluate toxicity, anti-stress activity and hepato-protective properties of Kombucha tea. Kombucha tea was fed orally for 15 days using three different doses i.e. normal dose, five and ten times the dose. Rats were then sacrificed and various biochemical, and histological parameters were estimated. Anti-stress activity was evaluated either by 1) by exposing animals to cold and hypoxia and estimating the levels of malondialdehyde and reduced glutathione in plasma/blood or 2) by subjecting the animals to restraint stress and recording faecal output. Hepato-toxicity was induced by challenging the animals to an acute dose of paracetamol (1 gm/kg) orally and determining the plasma levels of SGPT, SGOT and MDA. The effect of oral administration of different doses of K-tea to albino rats was examined and the results indicate that K-tea has no significant toxicity as revealed by various biochemical and histopathological parameters. K-tea has been found to prevent lipid peroxidation and fall in reduced glutathione level when rats were exposed to cold and hypoxia in simulated chamber. Further, K-tea has also been found to decrease the Wrap-restraint faecal pellet output in rats. K-tea has also been found to decrease paracetamol induced hepatotoxicity significantly. The study shows that K-tea has anti-stress and hepato-protective activities.

Validity and reliability of the Cohen 10-item Perceived Stress Scale in patients with chronic headache: Persian version.

PubMed

Khalili, Robabe; Sirati Nir, Masoud; Ebadi, Abbas; Tavallai, Abbas; Habibi, Mehdi

2017-04-01

The Cohen Perceived Stress Scale is being used widely in various countries. The present study evaluated the validity and reliability of the Cohen 10-item Perceived Stress Scale (PSS-10) in assessing tension headache, migraine, and stress-related diseases in Iran. This study is a methodological and cross-sectional descriptive investigation of 100 patients with chronic headache admitted to the pain clinic of Baqiyatallah Educational and Therapeutic Center. Convenience sampling was used for subject selection. PSS psychometric properties were evaluated in two stages. First, the standard scale was translated. Then, the face validity, content, and construct of the translated version were determined. The average age of participants was 38 years with a standard deviation (SD) of 13.2. As for stress levels, 12% were within the normal range, 36% had an intermediate level, and 52% had a high level of stress. The face validity and scale content were remarkable, and the KMO coefficient was 0.82. Bartlett's test yielded 0.327 which was statistically significant (p<0.0001) representing the quality of the sample. In factor analysis of the scale, the two elements of "coping" and "distress" were determined. A Cronbach's Alpha coefficient of 0.72 was obtained. This confirmed the remarkable internal consistency and stability of the scale through repeated measure tests (0.93). The Persian PSS-10 has good internal consistency and reliability. The availability of a validated Persian PSS-10 would indicate a link between stress and chronic headache. Copyright © 2017 Elsevier B.V. All rights reserved.

Coping with Stress among Pregnant Women with Gestational Diabetes Mellitus.

PubMed

Sürücü, Hamdiye Arda; Besen, Dilek Büyükkaya; Duman, Mesude; Yeter Erbil, Elif

2018-03-01

Introduction: The stress of pregnancy itself, gestational diabetes mellitus (GDM) that develops during pregnancy is also a stressor, because it can cause serious maternal and fetal health problems. The aim of this study was to examine the relationships between the characteristics of pregnant women with GDM and their styles of coping with stress. Methods: This descriptive cross-sectional study was conducted on 126 pregnant women with GDM. The sample consisted of patients who applied to the diabetes mellitus training polyclinic of a training and research and university hospital in southeastern Turkey, Data were evaluated using descriptive statistics, Kolmogorov-Smirnov normality tests, Spearman's rho and Pearson Correlation analysis, the Student's t-test, Mann-Whitney U-test and Kruskal-Wallis- test by SPSS software (version 13.0). Results: It was determined that a planned pregnancy, a high educational level, a first pregnancy and weight gain were important factors in the women with GDM in the study who coped effectively with stress during pregnancy. Unemployment and a second or subsequent pregnancy were important factors in the women with GDM< who coped ineffectively with stress during pregnancy. In addition, it was determined that the hemoglobin HbA1c levels of the pregnant women with GDM with "optimistic" and "submissive" approaches towards coping with stress were lower. Conclusion: It was determined that pregnant women with optimistic and submissive approaches towards coping with stress had lower HbA1c levels. It is suggested that randomized controlled studies be conducted to further determine the coping styles of patients with GDM.

Modeling consequences of prolonged strong unpredictable stress in zebrafish: Complex effects on behavior and physiology.

PubMed

Song, Cai; Liu, Bai-Ping; Zhang, Yong-Ping; Peng, Zhilan; Wang, JiaJia; Collier, Adam D; Echevarria, David J; Savelieva, Katerina V; Lawrence, Robert F; Rex, Christopher S; Meshalkina, Darya A; Kalueff, Allan V

2018-02-02

Chronic stress is the major pathogenetic factor of human anxiety and depression. Zebrafish (Danio rerio) have become a novel popular model species for neuroscience research and CNS drug discovery. The utility of zebrafish for mimicking human affective disorders is also rapidly growing. Here, we present a new zebrafish model of clinically relevant, prolonged unpredictable strong chronic stress (PUCS). The 5-week PUCS induced overt anxiety-like and motor retardation-like behaviors in adult zebrafish, also elevating whole-body cortisol and proinflammatory cytokines - interleukins IL-1β and IL-6. PUCS also elevated whole-body levels of the anti-inflammatory cytokine IL-10 and increased the density of dendritic spines in zebrafish telencephalic neurons. Chronic treatment of fish with an antidepressant fluoxetine (0.1mg/L for 8days) normalized their behavioral and endocrine phenotypes, as well as corrected stress-elevated IL-1β and IL-6 levels, similar to clinical and rodent data. The CNS expression of the bdnf gene, the two genes of its receptors (trkB, p75), and the gfap gene of glia biomarker, the glial fibrillary acidic protein, was unaltered in all three groups. However, PUCS elevated whole-body BDNF levels and the telencephalic dendritic spine density (which were corrected by fluoxetine), thereby somewhat differing from the effects of chronic stress in rodents. Together, these findings support zebrafish as a useful in-vivo model of chronic stress, also calling for further cross-species studies of both shared/overlapping and distinct neurobiological responses to chronic stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Perceived stress and high fat intake: A study in a sample of undergraduate students

PubMed Central

Vidal, E. Jair; Alvarez, Daily; Martinez-Velarde, Dalia; Vidal-Damas, Lorena; Yuncar-Rojas, Kelly A.; Julca-Malca, Alesia

2018-01-01

Objectives Different studies have reported the association between perceived stress and unhealthy diet choices. We aimed to determine whether there is a relationship between perceived stress and fat intake among undergraduate medical students. Methods/Principal findings A cross-sectional study was performed including first-year medical students. The outcome of interest was the self-report of fat intake assessed using the Block Screening Questionnaire for Fat Intake (high vs. low intake), whereas the exposure was perceived stress (low/normal vs. high levels). The prevalence of high fat intake was estimated and the association of interest was determined using prevalence ratios (PR) and 95% confidence intervals (95%CI). Models were created utilizing Poisson regression with robust standard errors. Data from 523 students were analyzed, 52.0% female, mean age 19.0 (SD 1.7) years. The prevalence of high fat intake was 42.4% (CI: 38.2%–46.7%). In multivariate model and compared with those with lowest levels of stress, those in the middle (PR = 1.59; 95%CI: 1.20–2.12) and highest (PR = 1.92; 95%CI: 1.46–2.53) categories of perceived stress had greater prevalence of fat intake. Gender was an effect modifier of this association (p = 0.008). Conclusions Greater levels of perceived stress were associated with higher fat intake, and this association was stronger among males. More than 40% of students reported having high fat consumption. Our results suggest the need to implement strategies that promote decreased fat intake. PMID:29522535