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Factors affecting stress placement for English nonwords include syllabic structure, lexical class, and stress patterns of phonologically similar words.

Seventeen native English speakers participated in an investigation of language users' knowledge of English main stress patterns. First, they produced 40 two-syllable nonwords of varying syllabic structure as nouns and verbs. Second, they indicated their preference for first or second syllable stress of the same words in a perception task. Finally, they indicated words they considered to be phonologically similar to the nonwords. Analyses of variance on the production and perception data indicated that both syllabic structure and lexical class (noun or verb) had an effect on main stress assignment. In logistic regression analyses on the production and perception responses. predictions of stress placement made by (1) syllable structure, (2) lexical class, and (3) stress patterns of phonologically similar words all contributed significantly and uniquely to the prediction of main stress assignment. The results indicate that phonological theories of English word stress need to allow for multiple, competing, probabilistic factors in accounts of main stress placement including syllabic structure (most notably vowel length), lexical class, and stress patterns of phonologically similar words.

Adolescent↗

A key role for stress-induced satellite III transcripts in the relocalization of splicing factors into nuclear stress granules.

Exposure of cells to stressful conditions results in the rapid synthesis of a subset of specialized proteins termed heat shock proteins (HSPs) which function in protecting the cell against damage. The stress-induced activation of hsp genes is controlled by the heat shock transcription factor 1 (HSF1). At the cellular level, one of the most striking effects of stress is the rapid and reversible redistribution of HSF1 into a few nuclear structures termed nuclear stress granules which form primarily on the 9q12 locus in humans. Within these structures, HSF1 binds to satellite III repeated elements and drives the RNA polymerase II-dependent transcription of these sequences into stable RNAs which remain associated with the 9q12 locus for a certain time after synthesis. Other proteins, in particular splicing factors, were also shown to relocalize to the granules upon stress. Here, we investigated the role of stress-induced satellite III transcripts in the relocalization of splicing factors to the granules. We show that the recruitment of the two serine/arginine-rich (SR) proteins SF2/ASF and SRp30c requires the presence of stress-induced satellite III transcripts. In agreement with these findings, we identified the second RNA-recognition motif (RRM2) of hSF2/ASF as the motif required for the targeting to the granules, and we showed by immunoprecipitation that the endogenous hSF2/ASF protein is present in a complex with satellite III transcripts in stressed cells in vivo. Interestingly, satellite III transcripts also immunoprecipitate together with small nuclear ribonucleoproteins (snRNPs) in vivo whereas the intronless hsp70 transcripts do not, supporting the proposal that these transcripts are subject to splicing. Altogether, these data highlight the central role for satellite III transcripts in the targeting and/or retention of splicing factors into the granules upon stress.

Cell Nucleus Structures↗

A modeling analysis of rest-stress and stress-rest injection sequences in performing thallium-201 myocardial perfusion scintigraphy.

A new thallium-201 stress testing protocol is proposed in which rest images are obtained prior to stress images. The advantages of the new protocol are that it saves time and requires no special diet or activity restriction between imaging sets. A potential problem from reversing the standard imaging sequence is decreased sensitivity to stress perfusion defects owing to background counts from the rest image. Using a cardiac phantom, 74 sets of stress and rest images were simulated under the new protocol and the standard stress-redistribution-reinjection protocol. Seven observers were asked to classify the images as normal or abnormal and to distinguish ischemic from fixed defects. Differences in observer performances between the two protocols were compared. With the new protocol, observers had sensitivities of 75%-90% and specificities of 100% in identifying a perfusion defect on the stress study. Accuracy was improved if the image counts from the rest study contributed less than 40% of the final counts of the stress study. Detection of ischemic and fixed defects was as good as or better than with standard protocols. Based on the phantom model, rest followed immediately by stress imaging sequence is an advantageous alternative for thallium-201 stress testing. Clinical trials are necessary to further evaluate this new protocol.

Coronary Disease↗

The role of early adverse experience and adulthood stress in the prediction of neuroendocrine stress reactivity in women: a multiple regression analysis.

Sensitization of stress-responsive neurobiological systems as a possible consequence of early adverse experience has been implicated in the pathophysiology of mood and anxiety disorders. In addition to early adversities, adulthood stressors are also known to precipitate the manifestation of these disorders. The present study sought to evaluate the relative role of early adverse experience vs. stress experiences in adulthood in the prediction of neuroendocrine stress reactivity in women. A total of 49 women (normal volunteers, depressed patients, and women with a history of early abuse) underwent a battery of interviews and completed dimensional rating scales on stress experiences and psychopathology, and were subsequently exposed to a standardized psychosocial laboratory stressor. Outcome measures were plasma adrenocorticotropin (ACTH) and cortisol responses to the stress test. Multiple linear regression analyses were performed to identify the impact of demographic variables, childhood abuse, adulthood trauma, major life events in the past year, and daily hassles in the past month, as well as psychopathology on hormonal stress responsiveness. Peak ACTH responses to psychosocial stress were predicted by a history of childhood abuse, the number of separate abuse events, the number of adulthood traumas, and the severity of depression. Similar predictors were identified for peak cortisol responses. Although abused women reported more severe negative life events in adulthood than controls, life events did not affect neuroendocrine reactivity. The regression model explained 35% of the variance of ACTH responses. The interaction of childhood abuse and adulthood trauma was the most powerful predictor of ACTH responsiveness. Our findings suggest that a history of childhood abuse per se is related to increased neuroendocrine stress reactivity, which is further enhanced when additional trauma is experienced in adulthood.

Adrenocorticotropic Hormone↗

Dynamic reorientation of cultured cells and stress fibers under mechanical stress from periodic stretching.

Cell lines derived from rat aorta and frog kidney were cultured on elastic membrane, and mechanical stress was given to the cells by stretching the membrane periodically. Cell reorientation oblique to the direction of stretching occurred as a result of the rapid withdrawal of cell periphery located along the direction of stretching and gradual extension of the cell membrane toward the direction oblique to the direction of stretching. Dynamic reorganization of stress fibers in living cells was visualized by labeling stress fibers with TRITC(3)-actin or EGFP-tagged moesin fragments with actin-binding ability. Stress fibers aligned in the direction of stretching disappeared soon after the start of stretching and then obliquely reoriented stress fibers appeared. The stretch-induced reorientation of cultured cells was suppressed by an inhibitor of stretch-activated (SA) cation channels and by a Ca(2+) chelator. However, the rearrangement of stress fibers was not affected by these agents. From these results, we suggest that Ca(2+) influx via SA channels is involved in stretch-induced cell reorientation but stress fiber rearrangement is independent of SA channels. Therefore, cell reorientation does not simply depend on the arrangement of stress fibers but may be controlled by some additional mechanism(s) which is regulated by calcium signaling.

Actins↗

Cortical/hippocampal monoamines, HPA-axis changes and aversive behavior following stress and restress in an animal model of post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is characterized by monoaminergic and hypothalamic-pituitary-adrenal (HPA)-axis abnormalities. Understanding monoamine-HPA-axis responses following stress and restress may provide a greater understanding of the neurobiology of PTSD and of its treatment. Hippocampal and frontal cortex serotonin, noradrenaline and dopamine, plasma corticosterone and aversive behavior were studied in rats on day 1 and day 7 post acute stress (AS = sequential restraint stress, swim stress and halothane exposure), and on day 1 and day 7 post restress (RS = swim stress). After AS, there was an early increase in both avoidant behavior and corticosterone (1 h after stress), with subsequent normalisation (day 7), suggesting an adequate adaptive response to the stressor. However, restress (RS) evoked a significant early HPA-axis hyporesponsiveness (1 h after RS) and a later significant increase in avoidant behavior on day 7 post RS. Hippocampal serotonin, noradrenaline and dopamine concentrations were unchanged 1 h post AS, but were significantly raised on day 7 post AS. Restress, however, reduced serotonin and noradrenaline levels 1 h after and on day 7 post RS, respectively, while dopamine was unchanged. In the frontal cortex only dopamine levels were altered, being significantly elevated 1 h after AS, and reduced on day 7 post RS. AS and RS thus differently effect the HPA-axis, evoking regional-specific brain monoamine changes that underlie maladaptive behavior and other post stress-related sequelae.

Analysis of Variance↗

Assembly and reorientation of stress fibers drives morphological changes to endothelial cells exposed to shear stress.

Fluid shear stress greatly influences the biology of vascular endothelial cells and the pathogenesis of atherosclerosis. Endothelial cells undergo profound shape change and reorientation in response to physiological levels of fluid shear stress. These morphological changes influence cell function; however, the processes that produce them are poorly understood. We have examined how actin assembly is related to shear-induced endothelial cell shape change. To do so, we imposed physiological levels of shear stress on cultured endothelium for up to 96 hours and then permeabilized the cells and exposed them briefly to fluorescently labeled monomeric actin at various time points to assess actin assembly. Alternatively, monomeric actin was microinjected into cells to allow continuous monitoring of actin distribution. Actin assembly occurred primarily at the ends of stress fibers, which simultaneously reoriented to the shear axis, frequently fused with neighboring stress fibers, and ultimately drove the poles of the cells in the upstream and/or downstream directions. Actin polymerization occurred where stress fibers inserted into focal adhesion complexes, but usually only at one end of the stress fiber. Neither the upstream nor downstream focal adhesion complex was preferred. Changes in actin organization were accompanied by translocation and remodeling of cell-substrate adhesion complexes and transient formation of punctate cell-cell adherens junctions. These findings indicate that stress fiber assembly and realignment provide a novel mode by which cell morphology is altered by mechanical signals.

Actins↗

Probing the origins and control of shrinkage stress in dental resin-composites: I. Shrinkage stress characterization technique.

The accurate and reliable characterization of the polymerization shrinkage stress is becoming increasingly important, as the shrinkage stress still is a major drawback of current dimethacrylate-based dental materials and restricts its range of applications. The purpose of this research is to develop a novel shrinkage stress measurement device to elucidate the shrinkage stress evolution of dental restorative composites while allowing for controlled sample deformation during the polymerization. Furthermore, the device is designed to mimic the clinically relevant cusp-to-cusp displacement by systematically adjusting the instrument compliance, the bonded surface area/unbonded area by sample geometry, and the total bonded area by sample diameter. The stress measurement device based on the cantilever beam deflection theory has been successfully developed and characterized using a commercial dental composite. It was shown that this device is a highly effective, practical and reliable shrinkage stress measurement tool, which enables its facile applications to the investigation of shrinkage stress kinetics of both commercial and experimental composites, as well as for probing various aspects that dictate shrinkage stress development.

Biocompatible Materials↗

Relationship between acute stress disorder and posttraumatic stress disorder following mild traumatic brain injury.

OBJECTIVE: The aim of this study was to index the frequency of occurrence of acute stress disorder following mild traumatic brain injury and to determine its utility in predicting posttraumatic stress disorder (PTSD). METHOD: Consecutive adult patients who sustained a mild traumatic brain injury following a motor vehicle accident (N = 79) were assessed for acute stress disorder within 1 month of their trauma with the Acute Stress Disorder Inventory, a structured clinical interview based on DSM-IV criteria. Patients were followed up 6 months after the trauma (N = 63) and were administered the PTSD module of the Composite International Diagnostic Interview. RESULTS: Acute stress disorder was diagnosed in 14% of patients, and at follow-up 24% satisfied criteria for PTSD. Six months after the trauma PTSD was diagnosed in 82% of patients who had been diagnosed with acute stress disorder and in 11% of those who had not been diagnosed with acute stress disorder. CONCLUSIONS: These findings point to the frequency of PTSD following mild traumatic brain injury. While the criteria for acute stress disorder are useful in identifying those individuals who are at risk of developing chronic PTSD, the findings suggest that current criteria require modification in order to optimally predict PTSD following mild traumatic brain injury.

Accidents, Traffic↗

Acute stress disorder and posttraumatic stress disorder in victims of violent crime.

OBJECTIVE: In a group of crime victims recruited from the community, the authors investigated the ability of both a diagnosis of acute stress disorder and its component symptoms to predict posttraumatic stress disorder (PTSD) at 6 months. METHOD: A mixed-sex group of 157 victims of violent assaults were interviewed within 1 month of the crime. At 6-month follow-up 88% were reinterviewed by telephone and completed further assessments generating estimates of the prevalence of PTSD. RESULTS: The rate of acute stress disorder was 19%, and the rate of subsequent PTSD was 20%. Symptom clusters based on the DSM-IV criteria for acute stress disorder were moderately strongly interrelated. All symptom clusters predicted subsequent PTSD, but not as well as an overall diagnosis of acute stress disorder, which correctly classified 83% of the group. Similar predictive power could be achieved by classifying the group according to the presence or absence of at least three reexperiencing or arousal symptoms. Logistic regression indicated that both a diagnosis of acute stress disorder and high levels of reexperiencing or arousal symptoms made independent contributions to predicting PTSD. CONCLUSIONS: This exploratory study provides evidence for the internal coherence of the new acute stress disorder diagnosis and for the symptom thresholds proposed in DSM-IV. As predicted, acute stress disorder was a strong predictor of later PTSD, but similar predictive power may be possible by using simpler criteria.

Acute Disease↗

Two-year prospective evaluation of the relationship between acute stress disorder and posttraumatic stress disorder following mild traumatic brain injury.

OBJECTIVE: To assess the ability of acute stress disorder to predict posttraumatic stress disorder (PTSD), the relationship between acute stress disorder and PTSD over the 2 years following mild traumatic brain injury was determined. METHOD: Survivors of motor vehicle accidents who sustained mild traumatic brain injuries were assessed for acute stress disorder within 1 month of the trauma (N=79) and for PTSD at 6 months (N=63) and 2 years (N=50) posttrauma. RESULTS: Acute stress disorder was diagnosed in 14% of the patients. Among the patients who participated in all three assessments, 80% of the subjects who met the criteria for acute stress disorder were diagnosed with PTSD at 2 years. Of the total initial group, 73% of those diagnosed with acute stress disorder had PTSD at 2 years. CONCLUSIONS: This study provides further support for the utility of the acute stress disorder diagnosis as a predictor of PTSD but indicates that the predictive power of the diagnostic criteria can be increased by placing greater emphasis on reexperiencing, avoidance, and arousal symptoms.

Accidents, Traffic↗

Acute stress disorder, posttraumatic stress disorder, and depression in disaster or rescue workers.

OBJECTIVE: The events of Sept. 11, 2001, highlighted the importance of understanding the effects of trauma on disaster workers. To better plan for the health care of disaster workers, this study examined acute stress disorder, posttraumatic stress disorder (PTSD), early dissociative symptoms, depression, and health care utilization in disaster workers. METHOD: Exposed disaster workers (N=207) and unexposed comparison subjects (N=421) were examined at 2, 7, and 13 months after an airplane crash. RESULTS: Exposed disaster workers had significantly higher rates of acute stress disorder, PTSD at 13 months, depression at 7 months, and depression at 13 months than comparison subjects. Those who were younger and single were more likely to develop acute stress disorder. Exposed disaster workers with acute stress disorder were 3.93 times more likely to be depressed at 7 months. Those with high exposure and previous disaster experience or who had acute stress disorder were more likely to develop PTSD. Similarly, those who were depressed at 7 months were 9.5 times more likely to have PTSD. Those who were depressed at 13 months were 7.96 times more likely to also meet PTSD criteria. More exposed disaster workers than comparison subjects obtained medical care for emotional problems at 2, 7, and 13 months. Overall, 40.5% of exposed disaster workers versus 20.4% of comparison subjects had acute stress disorder, depression at 13 months, or PTSD. CONCLUSIONS: Exposed disaster workers are at increased risk of acute stress disorder, depression, or PTSD and seek care for emotional problems at an increased rate.

Accidents, Aviation↗

Acute stress disorder and posttraumatic stress disorder in children and adolescents involved in assaults or motor vehicle accidents.

OBJECTIVE: The authors investigated acute stress disorder and later posttraumatic stress disorder (PTSD) in children and adolescents who had been involved in assaults or motor vehicle accidents. METHOD: They interviewed 93 patients 10-16 years old who were seen in an emergency department for having been assaulted or involved in a motor vehicle accident within 4 weeks after the assault or accident to assess acute stress disorder. At 6 months, they reinterviewed 64 (68.8%) of the patients to assess PTSD. RESULTS: At initial interview, 18 (19.4%) of the 93 patients had acute stress disorder and 23 (24.7%) met all acute stress disorder criteria except dissociation. At 6 months, eight of the 64 patients (12.5%) had PTSD. Acute stress disorder and PTSD did not differ in prevalence between patients who had been assaulted and those who had been in accidents. Sensitivity and specificity statistics and regression modeling revealed that the diagnosis of acute stress disorder was a good predictor of later PTSD but that dissociation did not play a significant role. CONCLUSIONS: Acute stress disorder has merit as a predictor of later PTSD in children and adolescents, but dissociation has questionable utility.

Accidents, Traffic↗

Biting reduces acute stress-induced oxidative stress in the rat hypothalamus.

We investigated the inhibitory effect of para-masticatory activity, namely biting, on restraint stress-induced oxidative stress. A blood brain barrier-permeable nitroxyl spin probe, 3-methoxycarbonyl-2,2,5,5,-tetramethylpyrrolidine-1-oxyl (MC-PROXYL), was administered to rats and L-band electron spin resonance (ESR) and ESR-computerized tomography (ESR-CT) imaging were used to show that the decay rate constant of MC-PROXYL in the hypothalamus of isolated brain after 30 min of restraint stress was more rapid than in unrestrained control rats, suggesting that restraint was associated with oxidative stress. Interestingly, biting during restraint stress caused the decay rate constant of MC-PROXYL in isolated brain to approach that of the control group. These observations suggest that biting suppresses oxidative stress induced by restraint stress, and that the anti-stress effect of masticatory motor activity movements, such as biting, are important for reducing the adverse effects associated with exposure to psychological stressors.

Animals↗

Changes in the FDP (fibrin and fibrinogen degradation products) value under mental and physical stress. I. Changes in FDP and other indices of physio-biochemical effects of stress loaded on volleyball players during training.

It has been known that CA change during physical exercises and associate with dynamic aspects of the coagulation fibrinolysis system of the blood. Therefore, we studied fibrin and fibrinogen degradation products (FDP) under physical exercises together with LDH, CPK, LA, CRE, Na, K and P. 1) College students of Department of Education majoring in sciences of physical education significantly increased activities of CPK and LDH during the training for volleyball games compared with the pre-training values. This increment was remarkable for those who exercised hard, that is, who were loaded with large physical stress. 2) Changes in LA were included in the range of its normal values. Freshmen who had not been trained much and consequently whose adaptability for physical stress was insufficient increased the LA level significantly relative to the pre-training level. 3) Although changes in P were included in the range of its normal values, significant increase was observed by physical stress. Examinations by individual disclosed that a tendency of changes in P was similar to that in CPK and FDP. 4) The tendency of changes in FDP agreed with that in CPK and P and an increase was observed for those who were loaded with large physical stress. It was further observed that especially for those who were loaded with large mental stress together with physical stress the increase in FDP was evident. Therefore, it has been suggested that FDP can be used as an index of biotic effects of not only physical stress but also mental stress.

Adult↗

Exercise and oxidative stress: significance of antioxidants with reference to inflammatory, muscular, and systemic stress.

Many studies have demonstrated that intense muscular work generates considerable amounts of reactive oxygen species (ROS). In order to prevent oxidative stress, the body contains a large number of nonenzymatic and enzymatic antioxidants that either prevent ROS formation or scavenge radical species. Oxidative stress can lead to damage or destruction of cellular macromolecules such as lipids, proteins, and nucleic acids. Therefore, oxidative stress has been associated with decreased physical performance, muscular fatigue, muscle damage, and overtraining. It has been hypothesized that the body's physiological amount of antioxidants is not sufficient to prevent exercise-induced oxidative stress and that additional antioxidants are needed to reduce oxidative stress, muscular damage, or overshooting inflammation. However, some but not all investigations have demonstrated oxidative stress following physical exercise, and also, findings concerning the role of antioxidants in reducing oxidative stress are equivocal. In addition, a clear association between the amount of exercise-induced muscular, metabolic, hormonal, or inflammatory stress and levels of antioxidant vitamins could not be established consistently. Therefore, although the theoretical background may be sound, there is no scientific evidence to recommend increased quantities of antioxidants to physically active people exceeding the amount provided by a healthy, balanced nutrition.

Animals↗

Persistent changes in corticotropin-releasing factor systems due to early life stress: relationship to the pathophysiology of major depression and post-traumatic stress disorder.

In addition to a genetic contribution to the vulnerability for mood and anxiety disorders, such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD), a preeminent role of early adverse life events in the pathogenesis of these disorders has been postulated. Corticotropin releasing factor (CRF), which has been conclusively documented to be the major regulator of the mammalian stress response, may be the seminal neurobiological substrate mediating the effects of early life stress on subsequent psychopathology. Central administration of CRF produces many of the physiological and behavioral effects of stress and of anxiety and depression. Clinical studies have provided evidence for increased activation of CRF neuronal systems in both MDD and PTSD. Similar hyperactivity of CRF neurons and sensitization of the pituitary-adrenal stress response has been observed in adult animals exposed to stress early in life. We propose that early adverse life events might render the human individual vulnerable to the effects of stress later in life, resulting in an increased risk for developing psychopathology via long-lived alterations in CRF-containing neural circuits. Based on these findings, new therapies including early intervention can now be developed to treat individuals exposed to severe stress early in life.

Adult↗

Luteal phase ovarian steroids, stress arousal, premenses perceived stress, and premenstrual symptoms.

The purpose of this study was to examine the relationships among perceived stress, ovarian steroids (estradiol and pregnanediol), stress arousal indicators (cortisol, catecholamines) and premenstrual symptoms (turmoil, fluid retention). Women (N = 74) with low symptom severity (LS), premenstrual syndrome (PMS), or premenstrual magnification (PMM) symptom patterns provided daily urine samples over one cycle and recorded their symptoms and perceived stress levels in a health diary. Multiple regression analysis was used to test models of premenstrual symptoms in separate analyses for women with the LS and PMS symptom patterns and the LS and PMM symptom patterns. Data from the LS and PMS groups revealed that greater stress ratings accounted for turmoil symptoms and higher luteal phase cortisol levels for fluid retention symptoms. For LS and PMM groups, lower luteal phase norepinephrine levels, higher global stress ratings, and a more gradual drop in estradiol premenses accounted for turmoil symptoms. Premenses norepinephrine and epinephrine levels and premenses stress ratings accounted for fluid retention. These findings support an important relationship among perceived stress, stress arousal indicators, and premenstrual symptoms that differs for women with a PMS and PMM symptom pattern.

Adult↗