Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STRESS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources
PubMed1998

A cyanobacterium lacking iron superoxide dismutase is sensitized to oxidative stress induced with methyl viologen but Is not sensitized to oxidative stress induced with norflurazon

A strain of Synechococcus sp. strain PCC 7942 with no functional Fe superoxide dismutase (SOD), designated sodB-, was characterized by its growth rate, photosynthetic pigments, and cyclic photosynthetic electron transport activity when treated with methyl viologen or norflurazon (NF). In their unstressed conditions, both the sodB- and wild-type strains had similar chlorophyll and carotenoid contents and catalase activity, but the wild type had a faster growth rate and higher cyclic electron transport activity. The sodB- was very sensitive to methyl viologen, indicating a specific role for the FeSOD in protection against superoxide generated in the cytosol. In contrast, the sodB- mutant was less sensitive than the wild type to oxidative stress imposed with NF. This suggests that the FeSOD does not protect the cell from excited singlet-state oxygen generated within the thylakoid membrane. Another up-regulated antioxidant, possibly the MnSOD, may confer protection against NF in the sodB- strain. These results support the hypothesis that different SODs have specific protective functions within the cell.

Journal Article↗
PubMed1997

Cortisol and glucose responses after acute stress by net handling in the sparid red porgy previously subjected to crowding stress

In red porgy Pagrus pagrus subjected to 3 weeks of chronic stress by crowding, plasma cortisol remained significantly higher in crowded fish compared to controls. There was no significant effect of crowding on plasma glucose levels. When the crowded fish were subjected to an acute handling the plasma cortisol response was similar to that of the uncrowded fish. No significant differences were found between the groups. The changes in plasma glucose following acute handling were also similar in both crowded and uncrowded fish.

Journal Article↗
PubMed2005

Hypothalamo-pituitary-adrenocortical axis in stress-susceptible and stress-resistant pigs: endocrine responses to corticotrophin-releasing factor and vasopressin.

Swiss Landrace pigs selected into genetically well-characterized low and high tissue fat lines (f and F respectively) react differently to exogenous and endogenous stressors. Response of the hypothalamo-pituitary-adrenocortical (HPA) axis to i.v. administered ovine corticotrophin-releasing factor (oCRF) and lysine vasopressin (LVP) in young females, intact and pretreated with dexamethasone or metyrapone, leads to the conclusion that different stress susceptibility of the two lines correlates with the sensitivity of pituitary corticotrophs to oCRF stimulation. Total amount of ACTH released after stimulation with submaximal oCRF doses was roughly equal in both lines, and cortisol level is even lower in the f-line, most likely due to the considerably enhanced metabolic clearance rate of cortisol (lower half-life of plasma cortisol compared with F-line). LVP-stimulated ACTH release is comparable with that of oCRF is stronger in the f-line. Combined effect of oCRF and LVP is rather additive than synergistic but the half-life ratio cortisol/ACTH after this stimulation is about four times higher than for stimulation by LVP and oCRF separately. In cases of externally stimulated HPA axis, cortisol plasma concentration tightly cross-correlates with that of ACTH.

Adrenocorticotropic Hormone↗
PubMed2006

Salt stress upregulates periplasmic arabinogalactan proteins: using salt stress to analyse AGP function.

Arabinogalactan proteins (AGPs) are implicated in cell expansion by unknown mechanisms, thus AGP content and cell-expansion rate might be correlated. We used Yariv reagent to quantify release rates and distribution of AGP at the cell surface of tobacco BY-2 cells: plasma membrane (M); soluble periplasmic AGPs released by cell rupture (S); cell wall (W); and growth medium (Gsink). In contrast to earlier reports, we observed massive upregulation of AGPs in salt-stressed cells, and hence the absence of a simple, direct cause-and-effect relationship between growth rate and AGP release. There was a more subtle connection. A dynamic flux model, M-->S-->W-->Gsink, indicated that turnover was nondegradative, with little free diffusion of AGPs trapped in the pectic matrix of nonadapted cells where transmural migration of high molecular-weight AGPs occurred mainly by plug flow (apposition and extrusion). In contrast, however, an up to sixfold increased AGP release rate in the slower-growing salt-adapted cells indicated a greatly increased rate of AGP diffusion through a much more highly porous pectic network. We hypothesize that classical AGPs act as pectin plasticizers. This explains how beta-D-glycosyl Yariv reagents might inhibit expansion growth by crosslinking monomeric AGPs, and thus mimic an AGP loss-of-function mutation.

Acclimatization↗
PubMed1979

The relative value of the non-stress and stress cardiotocograph: a protocol and pilot study.

A simple and safe protocol is described for the conduct of a controlled comparison of the relative predictive values of the antenatal cardiotocograph in the absence and in the presence of artificial stress (oxytocin challenge) to the fetus. Each patient serves as her own control, the tests are performed on the same day, and labour also commences on the same day, so that fetal performance in labour and status at birth are closely related in time to both tests and provide a reasonable assessment of the relative value of the tests. A pilot study of 83 patients has been carried out and the results are presented.

Electrocardiography↗
PubMed1997

Stress proteins and stress tolerance in an Antarctic, psychrophilic yeast, Candida psychrophila.

Conditions are described for the heat shock acquisition of thermotolerance, peroxide tolerance and synthesis of heat shock proteins (hsps) in the Antarctic, psychrophilic yeast Candida psychrophila. Cells grown at 15 degrees C and heat shocked at 25 degrees C (3 h) acquired tolerance to heat (35 degrees C) and hydrogen peroxide (100 mM). Novel heat shock inducible proteins at 80 and 110 kDa were observed as well as the presence of hsp 90, 70 and 60. The latter hsps were not significantly heat shock inducible. The absence of hsp 104 was intriguing and it was speculated that the 110 kDa protein may play a role in stress tolerance in psychrophilic yeasts, similar to that of hsp 104 in mesophilic species.

Candida↗
PubMed2006

Stress-ING out: phosphoinositides mediate the cellular stress response.

Phosphoinositides regulate numerous cellular processes required for growth, proliferation, and motility. Whereas phosphoinositide signal transduction pathways within the cytosol have been well characterized, nuclear signaling pathways remain poorly understood. Accumulating experimental data have now started to uncover critical functions for nuclear phosphoinositides. In particular, phosphoinositides modulate the activity of the tumor suppressor protein ING2 in response to extracellular stress. These findings highlight a previously uncharacterized function for phosphoinositides and implicate their metabolism in signaling pathways critical for cell survival.

Animals↗
PubMed1996

Role of osmolytes in adaptation of osmotically stressed and chill-stressed Listeria monocytogenes grown in liquid media and on processed meat surfaces.

Listeria monocytogenes is a food-borne pathogen that is widely distributed in nature and is found in many kinds of fresh and processed foods. The pervasiveness of this organism is due, in part, to its ability to tolerate environments with elevated osmolarity and reduced temperatures. Previously, we showed that L. monocytogenes adapts to osmotic and chill stress by transporting the osmolyte glycine betaine from the environment and accumulating it intracellularly (R. Ko, L. T. Smith, and G. M. Smith, J. Bacteriol. 176:426-431, 1994). In the present study, the influence of various environmental conditions on the accumulation of glycine betaine and another osmolyte, carnitine, was investigated. Carnitine was shown to confer both chill and osmotic tolerance to the pathogen but was less effective than glycine betaine. The absolute amount of each osmolyte accumulated by the cell was dependent on the temperature, the osmolarity of the medium, and the phase of growth of the culture. L. monocytogenes also accumulated high levels of osmolytes when grown on a variety of processed meats at reduced temperatures. However, the contribution of carnitine to the total intracellular osmolyte concentration was much greater in samples grown on meat than in those grown in liquid media. While the amount of each osmolyte in meat was less than 1 nmol/mg (fresh weight), the overall levels of osmolytes in L. monocytogenes grown on meat were about the same as those in liquid samples, from about 200 to 1,000 nmol/mg of cell protein for each osmolyte. This finding suggests that the accumulation of osmolytes is as important in the survival of L. monocytogenes in meat as it is in liquid media.

Adaptation, Physiological↗
PubMed1996

Hypochlorous acid stress in Escherichia coli: resistance, DNA damage, and comparison with hydrogen peroxide stress.

We have investigated the mechanisms of killing of Escherichia coli by HOCl by identifying protective functions. HOCl challenges were performed on cultures arrested in stationary phase and in exponential phase. Resistance to HOCl in both cases was largely mediated by genes involved in resistance to hydrogen peroxide (H2O2). In stationary phase, a mutation in rpoS, which controls the expression of starvation genes including those which protect against oxidative stress, renders the cells hypersensitive to killing by HOCl. RpoS-regulated genes responsible for this sensitivity were dps, which encodes a DNA-binding protein, and, to a lesser extent, katE and katG, encoding catalases; all three are involved in resistance to H2O2. In exponential phase, induction of the oxyR regulon, an adaptive response to H2O2, protected against HOCl exposure, and the oxyR2 constitutive mutant is more resistant than the wild-type strain. The genes involved in this oxyR-dependent resistance have not yet been identified, but they differ from those primarily involved in resistance to H2O2, including katG, ahp, and dps. Pretreatment with HOCl conferred resistance to H2O2 in an OxyR-independent manner, suggesting a specific adaptive response to HOCl. fur mutants, which have an intracellular iron overload, were more sensitive to HOCl, supporting the generation of hydroxyl radicals upon HOCl exposure via a Fenton-type reaction. Mutations in recombinational repair genes (recA or recB) increased sensitivity to HOCl, indicative of DNA strand breaks. Sensitivity was visible in the wild type only at concentrations above 0.6 mg/liter, but it was observed at much lower concentrations in dps recA mutants.

Bacterial Proteins↗
PubMed1997

A mutation in the ftsK gene of Escherichia coli affects cell-cell separation, stationary-phase survival, stress adaptation, and expression of the gene encoding the stress protein UspA.

An insertional mutation in ftsK, encoding an Escherichia coli product similar to the sporulation protein SpoIIIE of Bacillus subtilis, results in uspA overexpression in stationary phase and impairs cell division. The ftsK1::cat insertion mutant forms chains which are the result of inhibited cell-cell separation, while chromosome synthesis and partitioning appear to be normal as judged by flow cytometry and electron and light microscopy in combination with DNA staining. The cells of the chains are attached to each other by a small envelope structure, and unlike in a spoIIIE mutant of B. subtilis, there is no DNA trapped in the division plane. In addition, plasmids harboring a truncated ftsK allele lacking the last 195 bp of the gene cause chain formation in wild-type cells. While the mutant cells grow at essentially the same rate as the parent in complex and defined minimal media, they are sensitive to stresses. Specifically, the mutant failed to grow at elevated salt concentrations and survived stationary phase poorly. The phenotypes of the ftsK1::cat mutant are complemented by the 3' end (spoIIIE-like half) of the ftsK locus. In contrast, the 5' end of the ftsK locus reported to complement ftsK44(Ts) phenotypes does not complement the phenotypes of the ftsK1::cat mutant.

Bacterial Proteins↗
PubMed1997

Ribotoxic stress response: activation of the stress-activated protein kinase JNK1 by inhibitors of the peptidyl transferase reaction and by sequence-specific RNA damage to the alpha-sarcin/ricin loop in the 28S rRNA.

Inhibition of protein synthesis per se does not potentiate the stress-activated protein kinases (SAPKs; also known as cJun NH2-terminal kinases [JNKs]). The protein synthesis inhibitor anisomycin, however, is a potent activator of SAPKs/JNKs. The mechanism of this activation is unknown. We provide evidence that in order to activate SAPK/JNK1, anisomycin requires ribosomes that are translationally active at the time of contact with the drug, suggesting a ribosomal origin of the anisomycin-induced signaling to SAPK/JNK1. In support of this notion, we have found that aminohexose pyrimidine nucleoside antibiotics, which bind to the same region in the 28S rRNA that is the target site for anisomycin, are also potent activators of SAPK/JNK1. Binding of an antibiotic to the 28S rRNA interferes with the functioning of the molecule by altering the structural interactions of critical regions. We hypothesized, therefore, that such alterations in the 28S rRNA may act as recognition signals to activate SAPK/JNK1. To test this hypothesis, we made use of two ribotoxic enzymes, ricin A chain and alpha-sarcin, both of which catalyze sequence-specific RNA damage in the 28S rRNA. Consistent with our hypothesis, ricin A chain and alpha-sarcin were strong agonists of SAPK/JNK1 and of its activator SEK1/MKK4 and induced the expression of the immediate-early genes c-fos and c-jun. As in the case of anisomycin, ribosomes that were active at the time of exposure to ricin A chain or alpha-sarcin were able to initiate signal transduction from the damaged 28S rRNA to SAPK/JNK1 while inactive ribosomes were not.

Animals↗
PubMed1996

Comparison of dobutamine stress echocardiography with dipyridamole stress echocardiography for detection of viable myocardium after myocardial infarction treated with thrombolysis.

OBJECTIVE: To compare the ability of dobutamine and dipyridamole stress echocardiography to detect functional recovery of stunned but viable myocardial regions early after acute myocardial infarction, and to predict late functional recovery of the reperfusion salvaged myocardium within the infarct area. METHODS: Within 10 d of acute myocardial infarction, 51 patients--30 anterior and 21 inferior, 44 Q wave and seven non-Q-wave infarction--were submitted to a dobutamine echocardiography test at low dose (5-10 micrograms/kg/min over 5 min) and high dose (20-40 micrograms/kg/min over 3 min) and to dipyridamole echocardiography test (0.56 mg/kg over 4 min + 0.28 mg/kg over 2 min) on different days and in random order, after interruption of any vasoactive drug. Resting echocardiography was repeated at two months in 41 of 51 patients (80%). Regional wall motion of the left ventricle was analysed in a semiquantitative manner on a 14-segment model. Viability was defined as improvement of one grade or more of at least two basally asynergic segments in the infarcted area. RESULTS: Regional functional recovery was detected by low dose dobutamine in 38/51 patients (75%) and in 147/308 (48%) of basally asynergic segments, compared to 25/51 patients (49%; P < 0.001) and 78/308 segments (25%; P < 0.001) only identified by dipyridamole. Late spontaneous functional recovery was detected in 24/41 patients (59%) and in 78/254 basally asynergic segments (31%). The sensitivity of dobutamine and dipyridamole echocardiography for predicting spontaneous functional recovery was 72% and 51% respectively (P < 0.001), specificity 68% and 82% (P < 0.001), positive predictive value 50% and 56%, and negative predictive value 85% and 79%. CONCLUSIONS: In comparison with dipyridamole in patients with thrombolysed myocardial infarction, dobutamine induces regional functional recovery. This suggests that dobutamine is more sensitive in showing the presence of viable myocardium within the infarct zone, though it has a lower specificity in predicting delayed spontaneous functional recovery of non-contractile but still viable areas.

Coronary Angiography↗
PubMed2001

Can pre-treatment with beta-agonists reduce stress test time and the use of atropine in dobutamine stress testing?

AIM: To determine whether the use of inhaled beta-agonists decreases the duration of dobutamine stress testing (DAS), reduces the amount of dobutamine infused and decreases the use of atropine. METHODS: 34 patients on beta-agonists (group A) (mean age 65 +/- 8 years) and 32 patients not on beta-agonists or beta-blockers (group B) (mean age 65 +/- 10 years) undergoing DAS with SPECT were enrolled. RESULTS: The time of infusion of dobutamine in group A was 6.41 +/- 1.58 min and in group B was 9.77 +/- 3.60 min (p < 0.001). The amount of dobutamine infused was 10.64 +/- 5 mg in group A and 19.20 +/- 8 mg in group B (p < 0.001). In group A, 2 of 34 patients and 18 of 32 patients in group B needed atropine to reach peak HR (p < 0.001). CONCLUSION: Patients on short acting beta-agonists require smaller amounts of dobutamine with a shorter infusion time during DAS, and lesser use of side-effect prone atropine.

Administration, Inhalation↗
PubMed1995

Comparison of digital dipyridamole stress echocardiography and upright bicycle stress echocardiography for identification of coronary artery stenosis.

This study compared the diagnostic accuracy of dipyridamole (0.84 mg i.v./10 min) and bicycle stress echocardiography in 37 patients with inconclusive standard bicycle electrocardiography (ECG) tests; all underwent coronary angiography. Sensitivity for detection of coronary stenosis with dipyridamole echocardiography was 68% (21 of 31 patients), and for 1-, 2- and 3-vessel disease 56, 69 and 83%, respectively. Overall bicycle echocardiography sensitivity was 84%, and 78, 88 and 83% for patients with 1-, 2- and 3-vessel disease, respectively. Dipyridamole echocardiography was negative in all 6 patients with negative coronary angiography (specificity 100%), bicycle echocardiography was positive in 2 (specificity 67%). We conclude that dipyridamole echocardiography tends to be less sensitive in patients with mild disease, but is more specific than bicycle echocardiography.

Adult↗
PubMed1975

Predictive implications of stress testing. Follow-up of 2700 subjects after maximum treadmill stress testing.

Follow-up data on 2700 subjects who had had maximum stress tests were assembled in life tables. A positive test, characterized by ST-segment depression of 1.5 mm, 0.08 sec from the J point, predicted an incidence of some new coronary event of 9.5% a year, as compared with 1.7% in those with a negative test. The incidence of infarction and death was also significantly higher than in the negative responders. Early onset of ischemia occurring at moderate exercise (4 metabolic equivalents-METS) resulted in an incidence of all coronary events of 15% a year, while ischemia first manifested at the seventh minute of exercise (approximately 8 METS) results in an incidence of only 4% per year. The magnitude of ST depression and the age of onset of ischemia failed to influence the incidence of coronary events. A myocardial infarction previous to the test increased the incidence of events in both positive and negative responders. The positives with a previous infarction had more than double the incidence of coronary events than the positive responders with no pre-existing infarction. Those with chronotropic incompetence had a high incidence of coronary events even though the ECG response to exercise was normal.

Adult↗
PubMed1995

Dobutamine-atropine stress echocardiography in asymptomatic healthy individuals. The relativity of stress-induced hyperkinesia.

BACKGROUND: Interpretation of dobutamine-atropine stress echocardiography (DASE) is based on the assumption that the normal response to dobutamine-atropine infusion is characterized by increased systolic thickening and motion of the left ventricular (LV) walls, whereas a reduction or no change is considered indicative of coronary artery disease. The aim of this study was to quantitatively assess changes in LV dimension and wall motion patterns during DASE in a healthy population. METHODS AND RESULTS: Forty-two asymptomatic voluntary subjects (22 men) with a mean age of 59 years (range, 31 to 79 years) and a likelihood of < 5% for coronary artery disease underwent DASE with digital recording of two-dimensional and M-mode echocardiography at baseline and low-dose and peak infusion rates. Mean end-diastolic and end-systolic LV diameters and areas decreased and wall thicknesses increased progressively throughout the test. Wall motion and thickening increased from baseline to low-dose infusion in nearly all subjects. However, from low-dose to peak infusion, the mean absolute wall motion and relative wall thickening decreased by 13.1% (95% CI, 2.7 to 23.5) and 21.4% (95% CI, 6.4 to 36.4) regardless of age, sex, or use of atropine. Changes in fractional shortening and absolute wall thickening varied considerably, with a decrease observed in 15 and 13 individuals (36% and 31%), respectively. CONCLUSIONS: In healthy subjects, measures of wall motion and wall thickening increased from baseline to low-dose infusion but decreased from low-dose to peak infusion. These findings call for revision of the assumptions on which the common analysis of DASE is based.

Age Factors↗
PubMed1998

Health status, somatization, and severity of posttraumatic stress disorder in Vietnam combat veterans with posttraumatic stress disorder.

OBJECTIVE: A two-part study was conducted to examine the health status of Vietnam veterans with posttraumatic stress disorder (PTSD). In part 1, veterans with and without PTSD were compared on health behaviors and on self-reported and physician-rated health problems. Consistency of self-report with physician rating for health problems across the two groups was compared. In part 2, the association between health status and PTSD symptom severity, depression, somatization, and health behaviors in PTSD patients was evaluated. METHOD: In part 1, 276 combat veterans (225 with PTSD and 51 without PTSD) provided health status information, and medical records were reviewed. In part 2, 225 PTSD patients completed standardized PTSD severity, somatization, and depression measures. RESULTS: When analyses controlled for age, socioeconomic status, minority status, combat exposure, alcohol use, and pack-year history, veterans with PTSD reported and were rated as having a greater number of health problems than veterans without PTSD. Agreement between self-report and physician ratings for both groups ranged from low to moderate. Level of agreement between patient and physician was similar across groups. In the analysis of veterans with PTSD, somatization and PTSD symptom severity were significantly related to self-report of health problems, whereas only PTSD symptom severity was related to physician-rated health. Pack-year history was significantly related to self-reported health status in both groups. CONCLUSIONS: The presence and severity of PTSD in veterans were associated with greater physical health problems and conditions. Psychological variables (e.g., PTSD status, PTSD severity, somatization) and a behavioral variable (pack-year history) were related to health status.

Adult↗
PubMed2003

Tomato heat stress protein Hsp16.1-CIII represents a member of a new class of nucleocytoplasmic small heat stress proteins in plants.

We describe a new class of plant small heat stress proteins (sHsps) with dominant nuclear localization (Hsp17-CIII). The corresponding proteins in tomato, Arabidopsis, and rice are encoded by unique genes containing a short intron in the beta4-encoding region of the alpha-crystallin domain (ACD). The strong nuclear localization results from a cluster of basic amino acid residues in the loop between beta5 and beta6 of the ACD. Using yeast 2-hybrid tests, analyses of native complexes of the sHsps, and immunofluorescence data, we demonstrate that, in contrast to earlier observations (Kirschner et al 2000), proteins of the sHsp classes CI, CII, and CIII interact with each other, thereby influencing oligomerization state and intracellular localization.

Amino Acid Sequence↗