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 1,369 records · Page 76Linked to original sources
PubMed1977

Myocardial stress perfusion scintigraphy with rubidium-81 versus stress electrocardiography.

Fifty-six patients who subsequently underwent selective coronary angiography were studied noninvasively with relative myocardial perfusion scintigraphy with rubidium-81 and graded stress electrocardiography in an attempt to evaluate the ability of these tests to identify the presence of significant ischemia and, indirectly, coronary stenosis. Both the sensitivity (0.91) and specificity (0.91) of perfusion scintigraphy were impressive and better than the sensitivity (0.79) and specificity (0.64) of stress electrocardiography, the specificity of scintigraphy significantly so (P less than 0.05). Additionally, perfusion scintigraphy yielded excellent localizing information and was reliable even in the presence of drug effect, conduction abnormalities and nonspecific electrocardiographic abnormalities. Rare cases of triple vessel disease, prior myocardial infarction or single vessel disease with widespread collateral vessels were causes of scintigraphic misdiagnosis. Although ribidium-81 perfusion scintigraphy with the scintillation camera requires special collimation and significant quality control, it provides well resolved images and may prove particularly useful in facilitating quick successive multiple scintigraphic cardiac studies.

Angina Pectoris↗
PubMed2003

Low-frequency electromagnetic fields induce a stress effect upon higher plants, as evident by the universal stress signal, alanine.

15N NMR analysis reveals alanine production in Duckweed plants exposed to low intensity sinusoidally varying magnetic fields (SVMF) at 60 and 100Hz, and fed by 15N-labeled ammonium chloride. Alanine does not accumulate in the absence of SVMF. Addition of vitamin C, a radical scavenger, reduced alanine production by 82%, indicating the roll of free radicals in the process. Alanine accumulation in plants and animals in response to exposure to a variety of stress conditions, including SVMF, is a general phenomenon. It is proposed that alanine is a universal first stress signal expressed by cells.

Alanine↗
PubMed2002

Stress and the single cell: intrapopulation diversity is a mechanism to ensure survival upon exposure to stress.

We traditionally celebrate the capacity of bacteria for growth in a diverse range of environmental niches. As the attention has switched to their survival, we are no less impressed by the diversity of mechanisms that aid survival upon exposure to a variety of stresses. Mechanistically, we usually measure adaptation by the changes that occur upon rapid transfer from condition A to B. Implicit in such analyses is the homogeneity of the population of cells in terms of their biochemistry and responsiveness. In contrast, the literature contains many reports of heterogeneity within bacterial populations. A practical importance of such heterogeneity is the ability of a small fraction of any population to survive exposure to stresses that kill the majority of the population. The origins and properties of such organisms have been receiving renewed attention. This brief review considers some of the routes by which heterogeneity is generated in bacterial populations and suggests that such inherent transient diversity in phenotype of individual cells is a survival aid.

Adaptation, Physiological↗
PubMed1998

Purine stress in crithidia: adaptation of a parasite to environmental stress.

How parasitic protozoa survive varying nutrient levels is a key issue in parasitology. Here, Annette Gero explains how the Trypanosomatid Crithidia luciliae responds to purine stress by increasing the rates of transport of nucleosides and bases from the environment and by increasing the activity of the ectoenzyme 3'-nucleotidase (3'NTase), which breaks down external nucleotides so that they can be salvaged as nucleosides. The increase in activity of the purine transporters, and the 3'NTase activity is simultaneous with a general increase in the purine metabolic pathway, hence ensuring that purines are readily available to the parasite during purine stress.

Journal Article↗
PubMed1999

Cognitive-behavioral stress management buffers decreases in dehydroepiandrosterone sulfate (DHEA-S) and increases in the cortisol/DHEA-S ratio and reduces mood disturbance and perceived stress among HIV-seropositive men.

This study examined the effects of a 10-week cognitive-behavioral stress management (CBSM) intervention on dehydroepiandrosterone sulfate (DHEA-S) levels and the ratio of cortisol to DHEA-S (cortisol/DHEA-S), potential surrogate adrenal markers of HIV disease progression, in relation to alterations in mood and distress. HIV-seropositive men were randomized to either a group-based CBSM intervention (n = 43) or to a wait-list control group (n = 24), with both hormonal and distress measures assessed just prior to and immediately following the 10-week period. Results showed that CBSM buffers decreases in DHEA-S and increases in the cortisol/DHEA-S ratio. Further examination also revealed that changes in the cortisol/DHEA-S ratio were significantly and positively related to changes in total mood disturbance and perceived stress over time. These findings demonstrate that a short-term CBSM intervention can buffer against decrements in DHEA-S and increments in the cortisol/DHEA-S ratio among symptomatic, HIV-positive men, and that alterations in the cortisol/DHEA-S ratio move in concert with changes in mood and distress observed during CBSM.

Adolescent↗
PubMed2001

When to stress patients after coronary artery bypass surgery? Risk stratification in patients early and late post-CABG using stress myocardial perfusion SPECT: implications of appropriate clinical strategies.

OBJECTIVES: The study compared the prognostic significance of myocardial perfusion single-photon emission computed tomography (SPECT) (MPS) in patients early and late after coronary artery bypass graft surgery (CABG). BACKGROUND: The long-term effectiveness of CABG is limited by graft stenosis. The greatest incidence of graft occlusion occurs between five and eight years after surgery. However, little is known regarding the appropriate time to stress patients post-CABG with respect to risk stratification. METHODS: We identified 1,765 patients, who underwent MPS 7.1 +/- 5.0 years post-CABG. All patients underwent rest T1-201/stress Tc-99m sestamibi MPS and were followed up > or =1 year after testing. Patients with early CABG or PTCA (<60 days after MPS) were censored. The prognostic population consisted of 1,544 patients. A semiquantitative visual analysis employing a 20-segment model was used to define summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), and the number of nonreversible segments (NRS). RESULTS: During follow-up, 53 cardiac deaths (CD) occurred. There was a significant increase in annual CD rates as a function of SSS. A multivariate analysis identified age, ischemia (SDS), and infarct size (NRS) as independent predictors of CD. Nuclear variables added incremental value to prescan information. The annual CD rate was relatively low (1.3%) in patients < or =5 years post-CABG. In this subgroup only age and infarct size (NRS) were predictive of CD. CONCLUSION: MPS is strongly predictive of subsequent CD in post-CABG patients and adds incremental value over clinical and treadmill test information. Our data suggest that symptomatic patients < or =5 years and all patients >5 years post-CABG may benefit from testing.

Aged↗
PubMedDate not supplied

The comparative diagnostic value of dobutamine stress echocardiography and thallium stress tomography for detecting restenosis after coronary angioplasty.

The noninvasive detection of restenosis is clinically important for the subsequent management of patients in whom percutaneous transluminal coronary angioplasty (PTCA) has been performed. The aim of this study was to compare the diagnostic value of dobutamine stress echocardiography (DSE) and stress 201Tl single-photon emission computed tomography (SPECT) for detecting restenosis after PTCA. Fifty-three consecutive patients referred for the evaluation of possible restenosis or whom had been scheduled for follow-up study underwent DSE a mean of 5 months after angiographically successful PTCA. Dobutamine was infused incrementally under two-dimensional echocardiographic imaging. The left ventricle was divided into 16 segments and grouped into three coronary vascular territories. Rest, low-dose, and peak-dose images were digitized and displayed in a quad-screen format. Positive findings for restenosis were defined as new or worsened wall motion abnormality at a previously dilated vascular territory. All but one patient underwent SPECT. Positive findings for restenosis were defined as the presence of redistribution. All patients underwent quantitative coronary angiography after two tests. Restenosis was angiographically demonstrated in 23 (43%) of 53 patients and 25 (42) of 59 vessels. The sensitivity of DSE and SPECT for detecting restenosis was 78% and 74%, specificity was 93% and 93%, and accuracy was 87% and 85%, respectively. In a total of 59 vascular regions, DSE was 76% sensitive and 94% specific for detecting individual restenosis. It is concluded that DSE is comparable in diagnostic accuracy to SPECT for detecting restenosis in patients after PTCA.

Adrenergic beta-Agonists↗
PubMed2003

Stress management: MHC class I and class I-like molecules as reporters of cellular stress.

The evolutionarily ancient intracellular stress response protects cells from the effects of external and internal forces which perturb cellular metabolism. Members of the major histocompatibility complex (MHC) class I-like superfamily act as cell surface indicators of the intracellular stress response. Cellular immunity employs these indicators as a cue for elimination of damaged, infected, and malignant cells, promoting the health of the individual and the evolutionary success of the species.

Animals↗
PubMed2004

The water- and salt-stress-regulated Asr1 (abscisic acid stress ripening) gene encodes a zinc-dependent DNA-binding protein.

Tomato (Lycopersicon esculantum) ASR1 (abscisic acid stress ripening protein), a small plant-specific protein whose cellular mode of action defies deduction based on its sequence or homology analyses, is one of numerous plant gene products with unknown biological roles that become over-expressed under water- and salt-stress conditions. Steady-state cellular levels of tomato ASR1 mRNA and protein are transiently increased following exposure of plants to poly(ethylene glycol), NaCl or abscisic acid. Western blot and indirect immunofluorescence analysis with anti-ASR1 antibodies demonstrated that ASR1 is present both in the cytoplasmic and nuclear subcellular compartments; approx. one-third of the total ASR1 protein could be detected in the nucleus. Nuclear ASR1 is a chromatin-bound protein, and can be extracted with 1 M NaCl, but not with 0.5% Triton X-100. ASR1, overexpressed in Escherichia coli and purified to homogeneity, possesses zinc-dependent DNA-binding activity. Competitive-binding experiments and SELEX (systematic evolution of ligands by exponential enrichment) analysis suggest that ASR1 binds at a preferred DNA sequence.

Binding Sites↗
PubMedDate not supplied

[Shear fracture stress of the spongiosa and pressure fracture stress of cortical bone of cadaveric vertebrae].

By biomechanic examinations of the vertebrae of human dead bodies the ultimate stress due to shearing (Schubbruchspannung) of the spongy substance could be found out with 1.80 N/mm2 and the ultimate stress due to compression (Druckbruchspannung) of the cortical-belonging to the thick of cortical--with 280 N/mm2. Both measuring results are important for the ultimate strength of the connection (Verankerungsfestigkeit) of screws in vertebae.

Adolescent↗
PubMed1999

MEKK-1, a component of the stress (stress-activated protein kinase/c-Jun N-terminal kinase) pathway, can selectively activate Smad2-mediated transcriptional activation in endothelial cells.

Smad proteins are essential components of the intracellular signaling pathways utilized by members of the transforming growth factor-beta (TGF-beta) superfamily of growth factors. Certain Smad proteins (e.g. Smad1, -2, and -3) can act as regulated transcriptional activators, a process that involves phosphorylation of these proteins by activated TGF-beta superfamily receptors. We demonstrate that the intracellular kinase mitogen-activated protein kinase kinase kinase-1 (MEKK-1), an upstream activator of the stress-activated protein kinase/c-Jun N-terminal kinase pathway, can participate in Smad2-dependent transcriptional events in cultured endothelial cells. A constitutively active form of MEKK-1 but not mitogen-activated protein kinase kinase-1 (MEK-1) or TGF-beta-activated kinase-1, two distinct intracellular kinases, can specifically activate a Gal4-Smad2 fusion protein, and this effect correlates with an increase in the phosphorylation state of the Smad2 protein. These effects do not require the presence of the C-terminal SSXS motif of Smad2 that is the site of TGF-beta type 1 receptor-mediated phosphorylation. Activation of Smad2 by active MEKK-1 results in enhanced Smad2-Smad4 interactions, nuclear localization of Smad2 and Smad4, and the stimulation of Smad protein-transcriptional coactivator interactions in endothelial cells. Overexpression of Smad7 can inhibit the MEKK-1-mediated stimulation of Smad2 transcriptional activity. A physiological level of fluid shear stress, a known activator of endogenous MEKK-1 activity in endothelial cells, can stimulate Smad2-mediated transcriptional activity. These data demonstrate a novel mechanism for activation of Smad protein-mediated signaling in endothelial cells and suggest that Smad2 may act as an integrator of diverse stimuli in these cells.

Animals↗
PubMed1999

TL1, a novel tumor necrosis factor-like cytokine, induces apoptosis in endothelial cells. Involvement of activation of stress protein kinases (stress-activated protein kinase and p38 mitogen-activated protein kinase) and caspase-3-like protease.

TL1 is a recently discovered novel member of the tumor necrosis factor (TNF) cytokine family. TL1 is abundantly expressed in endothelial cells, but its function is not known. The present study was undertaken to explore whether TL1 induces apoptosis in endothelial cells and, if so, to explore its mechanism of action. Cultured bovine pulmonary artery endothelial cells (BPAEC) exposed to TL1 showed morphological (including ultrastructural) and biochemical features characteristic of apoptosis. TL1-induced apoptosis in BPAEC was a time- and concentration-dependent process (EC50 = 72 ng/ml). The effect of TL1 was not inhibited by soluble TNF receptors 1 or 2. TL1 up-regulated Fas expression in BPAEC at 8 and 24 h after treatment, and significantly activated stress-activated protein kinase (SAPK) and p38 mitogen-activated protein kinase (p38 MAPK). The peak activities of SAPK and p38 MAPK in TL1-treated BPAEC were increased by 9- and 4-fold, respectively. TL1-induced apoptosis in the BPAEC was reduced by expression of a dominant-interfering mutant of c-Jun (62.8%, p < 0.05) or by a specific p38 inhibitor, SB203580 (1-10 microM) dose-dependently. TL1 also activated caspases in BPAEC, and TL1-induced apoptosis in BPAEC was significantly attenuated by the caspase inhibitor, ZVAD-fluromethyl-ketone. The major component activated by TL1 in BPAEC was caspase-3, which was based on substrate specificity and immunocytochemical analysis. These findings suggest that TL1 may act as an autocrine factor to induce apoptosis in endothelial cells via activation of multiple signaling pathways, including stress protein kinases as well as certain caspases.

Animals↗
PubMed1995

Diagnosis of coronary artery disease and viable myocardium by stress echocardiography. Diagnostic accuracy of different stress modalities.

Stress echocardiography is being used more commonly for routine clinical diagnosis of coronary artery disease. In addition to physical treadmill or bicycle exercise echocardiography, pharmacological stress echocardiography with dobutamine and dipyridamole has also gained increasing significance over the past few years. Numerous studies have proven that these methods diagnose coronary artery disease accurately (exercise echocardiography: sensitivity 71 to 98%, specificity 64 to 100%, dobutamine echocardiography; sensitivity 54 to 96%, specificity 66 to 95%; dipyridamole echocardiography: sensitivity 57 to 74%, specificity 80 to 100%), but no direct comparison has hitherto been able to prove the superiority of any one of these protocols. However it is recognized that the skill and experience of the echocardiographer performing this study has an influence on the accuracy of the technique.

Coronary Disease↗
PubMed1989

Interaction of the fluorescent dye 1-N-phenylnaphthylamine with Escherichia coli cells during heat stress and recovery from heat stress.

The fluorescent dye 1-N-phenylnaphthylamine permeated Escherichia coli cells after exposure to a heat stress at 55 degrees C in Tris/Mg2+ buffer, pH 8.0. The rate of dye permeation increased with time during heat treatment and decreased gradually during subsequent incubation at 37 degrees C in a minimal medium. The initial level of rapid adsorption of the dye also increased with heating time, although it remained roughly constant during post-heating incubation. The results obtained suggest that the permeability barrier to the dye in the outer membrane was damaged by heat stress and was repaired after sublethal heating. RNA, protein and lipid syntheses, as well as an energy-yielding process, appeared to be necessary for the repair of impermeability to the dye.

1-Naphthylamine↗
PubMed2006

Shear stress, temperature, and inoculation concentration influence the adhesion of water-stressed Helicobacter pylori to stainless steel 304 and polypropylene.

Although molecular techniques have identified Helicobacter pylori in drinking water-associated biofilms, there is a lack of studies reporting what factors affect the attachment of the bacterium to plumbing materials. Therefore, the adhesion of H. pylori suspended in distilled water to stainless steel 304 (SS304) coupons placed on tissue culture plates subjected to different environmental conditions was monitored. The extent of adhesion was evaluated for different water exposure times, using epifluorescence microscopy to count total cell numbers. High shear stresses-estimated through computational fluid dynamics-negatively influenced the adhesion of H. pylori to the substrata (P < 0.001), a result that was confirmed in similar experiments with polypropylene (P < 0.05). However, the temperature and inoculation concentration appeared to have no effect on adhesion (P > 0.05). After 2 hours, H. pylori cells appeared to be isolated on the surface of SS304 and were able to form small aggregates with longer exposure times. However, the formation of a three-dimensional structure was only very rarely observed. This study suggests that the detection of the pathogen in well water described by other authors can be related to the increased ability of H. pylori to integrate into biofilms under conditions of low shear stress. It will also allow a more rational selection of locations to perform molecular or plate culture analysis for the detection of H. pylori in drinking water-associated biofilms.

Bacterial Adhesion↗
PubMed1993

Release of stress proteins from Mesocestoides corti is a brefeldin A-inhibitable process: evidence for active export of stress proteins.

Substantial evidence indicates that molecules released by infectious organisms affect virulence and influence immunity to infection. The characterization of extracellular molecules and their mechanism of release is therefore critical to understanding host-parasite relationships. The cestode parasite Mesocestoides corti is known to release at the larval stage several molecules including the heat shock proteins hsp70 and hsp60. In this report, it is shown that several molecules released by M. corti, including 70- and 60-kDa proteins, are induced by a temperature shift from room temperature to 37 degrees C. Such a shift is comparable to the thermal stress of parasites transmitted from insect vector to vertebrate host. By drug inhibition studies and Western blot (immunoblot) analyses, it is shown that M. corti hsp70 and hsp60 as well as other released molecules are actively exported. The active release of stress proteins by parasites has not been described and may play a critical role in the disease process.

Animals↗
PubMed2005

The stress-responsive gene GADD45G is a functional tumor suppressor, with its response to environmental stresses frequently disrupted epigenetically in multiple tumors.

The CpG island of GADD45G was identified as a target sequence during the identification of hypermethylated genes using methylation-sensitive representational difference analysis combined with 5-aza-2'-deoxycytidine demethylation. Located at the commonly deleted region 9q22, GADD45G is a member of the DNA damage-inducible gene family. In response to stress shock, GADD45G inhibits cell growth and induces apoptosis. Same as other GADD45 members, GADD45G is ubiquitously expressed in all normal adult and fetal tissues. However, its transcriptional silencing or down-regulation and promoter hypermethylation were frequently detected in tumor cell lines, including 11 of 13 (85%) non-Hodgkin's lymphoma, 3 of 6 (50%) Hodgkin's lymphoma, 8 of 11 (73%) nasopharyngeal carcinoma, 2 of 4 (50%) cervical carcinoma, 5 of 17 (29%) esophageal carcinoma, and 2 of 5 (40%) lung carcinoma and other cell lines but not in any immortalized normal epithelial cell line, normal tissue, or peripheral blood mononuclear cells. The silencing of GADD45G could be reversed by 5-aza-2'-deoxycytidine or genetic double knockout of DNMT1 and DNMT3B, indicating a direct epigenetic mechanism. Aberrant methylation was further frequently detected in primary lymphomas although less frequently in primary carcinomas. Only one single sequence change in the coding region was detected in 1 of 25 cell lines examined, indicating that genetic inactivation of GADD45G is very rare. GADD45G could be induced by heat shock or UV irradiation in unmethylated cell lines; however, this stress response was abolished when its promoter becomes hypermethylated. Ectopic expression of GADD45G strongly suppressed tumor cell growth and colony formation in silenced cell lines. These results show that GADD45G can act as a functional new-age tumor suppressor but being frequently inactivated epigenetically in multiple tumors.

Antigens, Differentiation↗
PubMed1978

Chronic gastric ulcer and stress. A comparison of an ulcer population with a control population regarding stressful events over a lifetime.

Stress was measured by the frequency of 31 major life events with consequent change and distress scores in 50 patients with chronic gastric ulcer and 50 control subjects, matched for age, sex and place of residence. The gastric ulcer population did not differ from the control population regarding the number of events experienced and the associated change and distress scores. However, when analysed according to social grade, the ulcer patients in the lower status suburbs experienced more events and more change than their controls, but the stress scores were similar. In the higher status suburbs, no difference was present between the patients and controls. Change and distress scores rose progressively with age, but there was no significant difference in the number of events experienced between the three age groups. Both men patients and their controls experienced significantly more events and higher change scores than women patients and their controls.

Adult↗