The Evaluation of Biomarkers of Physical Activity on Stress Resistance and Wellness

Physical activity can improve health as well as reduce stress and the risk of developing several widespread diseases. However, there exists no accepted standard biomedical examination-method for stress evaluation. The purpose of this study was to investigate the effect of regular physical activity on stress and wellness as well as the evaluation of potential biomarkers in this field. This study included 105 people (mean age = 36.57 ± 1.4 years) who were randomly assigned into the exercise group 1 (EG-1) (n = 41), the exercise group 2 (EG-2) (n = 30), and the control group (CG) (n = 34). Measurements of stress and wellness were obtained by Multiscan BC-OXI before and after experimental period. This device presents a multifrequency segmental body composition 3D analyser with digital pulse oximeter. The key indicators of stress as well as for wellness were significantly improved in the EG-1. Parasympathetic activity showed significant changes as potential stress biomarker. Statistically significant gender differences were not observed in the comparable groups. The results suggest that the stress resistance and well-being significantly improved in the EG-1 due to regular physical activity. However, further research is necessary to determine effects of physical activity on integral health indicators.

     

Impact of Mental and Physical Stress on Blood Pressure and Pulse Pressure under Normobaric versus Hypoxic Conditions

Objective

Hypobaric hypoxia, physical and psychosocial stress may influence key cardiovascular parameters including blood pressure (BP) and pulse pressure (PP). We investigated the effects of mild hypobaric hypoxia exposure on BP and PP reactivity to mental and physical stress and to passive elevation by cable car.

Methods

36 healthy volunteers participated in a defined test procedure consisting of a period of rest 1, mental stress task (KLT-R), period of rest 2, combined mental (KLT-R) and physical task (bicycle ergometry) and a last period of rest both at Graz, Austria (353 m asl) and at the top station Dachstein (2700 m asl). Beat-to-beat heart rate and BP were analysed both during the test procedures at Graz and at Dachstein and during passive 1000 m elevation by cable car (from 1702 m to 2700 m).

Results

A significant interaction of kind of stress (mental vs. combined mental and physical) and study location (Graz vs. Dachstein) was found in the systolic BP (p = .007) and PP (p = .002) changes indicating that during the combined mental and physical stress task sBP was significantly higher under hypoxic conditions whereas sBP and PP were similar during mental stress both under normobaric normoxia (Graz) and under hypobaric hypoxia (Dachstein). During the passive ascent in cable car less trivialization (psychological coping strategy) was associated with an increase in PP (p = .004).

Conclusion

Our data show that combined mental and physical stress causes a significant higher raise in sBP and PP under hypoxic conditions whereas isolated mental stress did not affect sBP and PP under hypoxic conditions. PP-reaction to ascent in healthy subjects is not uniform. BP reactions to ascent that represents an accumulation of physical (mild hypobaric hypoxia) and psychological stressors depend on predetermined psychological traits (stress coping strategies). Thus divergent cardiovascular reactions can be explained by applying the multidimensional aspects of the biopsychosocial concept.     

The Majority of the Migrant Factory Workers of the Light Industry in Shenzhen,China May Be Physically Inactive

Physical inactivity is a strong risk factor of non-communicable diseases (NCD). In China, there are 250 million migrant factory workers, who are susceptible to physical inactivity and hence NCD because of work nature and setting. With random stratified sampling, 807 such workers of the light industry were recruited in Shenzhen, China and completed a self-administered questionnaire with informed consent. The prevalence of inadequate physical activity (defined according to the World Health Organization’s recommendation on level of moderate/vigorous physical activity) was 95.4%. Of all participants, 69.1% showed “a very low level of physical activity” (VLLPA), defined as ≤30 minutes of weekly moderate/vigorous physical activity, which was significantly associated with female sex (Odds ratio [OR]=1.65), lower education level (OR=0.10 to 0.33, primary education as the reference group) and married status (OR=0.63, single status as the reference group). Adjusted for these factors, perceived social support (Adjusted OR=0.87) was negatively associated with VLLPA, while job stress due to workload, which was significant in the univariate analysis (OR=0.98), became non-significant (p=0.184). Significant interaction between perceived social support and perceived job stress onto VLLPA was found (p=0.044), implying that the negative association between job stress and VLLPA, which might reflect a potential response to cope with stress by performing exercises, was stronger among those with weaker social support. The extremely low level of physical activity rings an alarm, as it implies high risk of NCD, and as there are no existing programs promoting physical activity in this group. Interventions need to take into account social support, potential coping to job stress, and structural factors of the factory setting, while involving factories’ management.     

Mental stress induces sustained elevation of blood pressure and lipid peroxidation in postmenopausal women

Mental stress is thought to underlie cardiovascular events, but there is information on oxidative stress induced by mental stress in association with cardiovascular responses in women. Using a sensitive assay for plasma 4-hydroxy-2-nonenal (HNE), as a marker for oxidative stress, we addressed the relation between pressor responses and oxidative stress induced by mental or physical stress in premenopausal and postmenopausal women. Healthy subjects (7 postmenopausal and 8 premenopausal women, in early and late follicular phases) were subjected to mental and physical stress evoked by a Color Word Test (CWT) and isometric handgrip, respectively. The CWT induced a rapid elevation of diastolic blood pressure (DBP), at a higher level in the postmenopausal than in the premenopausal women (p<0.01), and this higher DBP was sustained during the CWT and recovery (p<0.01). The CWT induced a significant elevation in plasma noradrenaline in premenopausal women in the early follicular phase and in postmenopausal women (p<0.05). Plasma nitric oxide metabolites were higher in postmenopausal than in the premenopausal women in the late follicular phase (p<0.05), but did not change during exposure to the two types of stress in either group. Plasma HNE was increased during recovery from the CWT, but not the handgrip, in postmenopausal women (2.4 times, p<0.05). There was a significant difference in the time course of the CWT-induced HNE response between the postmenopausal and premenopausal women (p<0.05). These findings suggest that mental, but not physical, stress causes sustained diastolic blood pressure elevation in postmenopausal women, accompanied by heightened oxidative stress.     

The effect of physical stress on plant cells in suspension cultures

Summary The effect of the physical (hydrodynamic) stress generated by aeration and agitation in suspension cultures onCatharanthus roseus cells was studied. The intensity of the physical stress was closely related to the growth rate of the cells, the maximum cell mass, the size distribution of cell aggregates, the contents of the cell wall, and each component of the cell wall.     

Differential role of microenvironment in microencapsulation for improved cell tolerance to stress

The effect of the microenvironment in alginate–chitosan–alginate (ACA) microcapsules with liquid core (LCM) and solid core (SCM) on the physiology and stress tolerance of Sacchromyces cerevisiae was studied. The suspended cells were used as control. Cells cultured in liquid core microcapsules showed a nearly twofold increase in the intracellular glycerol content, trehalose content, and the superoxide dismutase (SOD) activity, which are stress tolerance substances, while SCM did not cause the significant physiological variation. In accordance with the physiological modification after being challenged with osmotic stress (NaCl), oxidative stress (H₂O₂), ethanol stress, and heat shock stress, the cell survival in LCM was increased. However, SCM can only protect the cells from damaging under ethanol stress. Cells released from LCM were more resistant to hyperosmotic stress, oxidative stress, and heat shock stress than cells liberated from SCM. Based on reasonable analysis, a method was established to estimate the effect of microenvironment of LCM and SCM on the protection of cells against stress factors. It was found that the resistance of LCM to hyperosmotic stress, oxidative stress, and heat shock stress mainly depend on the domestication effect of LCM’s microenvironment. The physical barrier of LCM constituted by alginate–chitosan membrane and liquid alginate matrix separated the cells from the damage of oxidative stress and ethanol stress. The significant tolerance against ethanol stress of SCM attributed to the physical barrier consists of solid alginate–calcium matrix and alginate–chitosan membrane.     

Effects of Stress from Mine Drainage on Diversity, Biomass, and Function of Primary Producers in Mountain Streams

This paper proposes a hypothesis that relates biodiversity, community biomass, and ecosystem function to a gradient of stress. According to this hypothesis, biodiversity has a low threshold of response to stress, whereas biomass and function are stable or increase under low to moderate stress and decrease only under high stress. This hypothesis was tested by examining communities of primary producers in streams under stress from mine drainage in the Rocky Mountains of Colorado, USA. Mine drainage exerts chemical stress (low pH, dissolved metals) as well as physical stress (deposition of metal oxides) on stream biota. Diversity of primary producers was usually more sensitive to stress from mine drainage than community biomass (chlorophyll a) or primary production. Diversity was negatively related to all stresses from mine drainage, but it was especially low in streams with low pH or high concentration of dissolved zinc. Biomass and production were high in streams with only chemical stress, but they were often low in streams with physical stress caused by metal oxide deposition. Stream sites with aluminum oxide deposition usually had very little algal biomass. The rate of metal oxide deposition, presence of aluminum oxides, and pH together explained 65% of the variation in biomass. The rate of net primary production was highly correlated with biomass and had a similar response to stress from mine drainage. Overall, chemical stresses (low pH, high concentration of zinc) generally led to the hypothesized trends in our model of ecosystems under stress. Physical stress (deposition of metal oxides), however, led to variable responses, and often decreased biomass and function even at low intensity, contrary to the original hypothesis. Thus, the nature of ecosystem response to stress may differ for chemical and physical stresses.     

Differential expression of heat shock protein 70 in relation to stress type in the flatworm <Emphasis Type="Italic">Schmidtea polychroa</Emphasis>

Most heat shock proteins help to cope with stress in organisms ranging from bacteria to vertebrates. Many stress types acting on the intensity of intracellular protein can induce expression of heat shock proteins. Here, we studied changes in expression level of heat shock protein 70 (Hsp70), one of the best investigated stress proteins, in response to five potential stress factors in the planarian flatworm Schmidtea polychroa: (1) homogenized planarian tissue, which releases an alarm substance that signals predation injury, (2) physical damage by puncturing, (3) a simulation of ecological competition by adding a mixture of naturally co-occurring species: one Dendrocoelum and two Polycelis flatworms, one Asellus water louse and one leech, and (4) magnesium chloride, which inhibits regeneration ability. We found that alarm substance (1), physical harm (2), and magnesium chloride (4) led to increased expression of Hsp70, while interspecific competition (3) did not result in elevated Hsp70 expression. There was no difference between the experimental negative control and two temporal controls immediately after collection and just before the experiment. Results show that Schmidtea polychroa is not sensitive to sampling and lab maintenance. However, planarian homogenate, magnesium chloride and physical harm all caused Hsp70-inducing stress. We conclude that Hsp70 quantification is appropriate to study the current stress level in planaria in response to specific conditions.     

Urinary dopamine in physical and mental effort

Dopamine in urine was investigated during three levels of physical stress (at 35%, 50%, and 75% VO2 max.) and three kinds of mental stress (delayed auditory feedback, vigilance task and arithmetic task). A statistically significant increase in excretion of dopamine was found in response to physical exercise and the delayed auditory feedback test. The response patterns (ratios noradrenaline/dopamine and adrenaline/dopamine) after physical and mental stress differed. The data presented support the possibility of using dopamine excretion and the above ratios to differentiate between mental and physical effort.     

Antioxidant effect of diphenyl diselenide on oxidative stress caused by acute physical exercise in skeletal muscle and lungs of mice

This study was designed to examine if diphenyl diselenide (PhSe)₂, an organoselenium compound, attenuates oxidative stress caused by acute physical exercise in skeletal muscle and lungs of mice. Swiss mice were pre‐treated with (PhSe)₂ (5 mg kg^‐1 day^‐1) for 7 days. At the 7th day, the animals were submitted to acute physical exercise which consisted of continuous swimming for 20 min. The animals were euthanized 1 and 24 h after the exercise test. The levels of thiobarbituric acid reactive species (TBARS), non‐protein thiols (NPSH) and ascorbic acid and the activity of catalase (CAT) were measured in the lungs and skeletal muscle of mice. Glycogen content was determined in the skeletal muscle of mice. Parameters in plasma (urea and creatinine) were determined. The results demonstrated an increase in TBARS levels induced by acute physical exercise in the skeletal muscle and lungs of mice. Animals submitted to exercise showed an increase in non‐enzymatic antioxidant defenses (NPSH and ascorbic acid) in the skeletal muscle. In lungs of mice, activity of CAT was increased. (PhSe)₂ protected against the increase in TBARS levels and ameliorated antioxidant defenses in the skeletal muscle and lungs of mice submitted to physical exercise. These results indicate that acute physical exercise caused a tissue‐specific oxidative stress in the skeletal muscle and lungs of mice. (PhSe)₂ protected against oxidative damage induced by acute physical exercise in mice. Copyright © 2009 John Wiley & Sons, Ltd.     

Contributions of individual σB-dependent general stress genes to oxidative stress resistance of Bacillus subtilis

The general stress regulon of Bacillus subtilis comprises approximately 200 genes and is under the control of the alternative sigma factor σ(B). The activation of σ(B) occurs in response to multiple physical stress stimuli as well as energy starvation conditions. The expression of the general stress proteins provides growing and stationary nonsporulating vegetative cells with nonspecific and broad stress resistance. A previous comprehensive phenotype screening analysis of 94 general stress gene mutants in response to severe growth-inhibiting stress stimuli, including ethanol, NaCl, heat, and cold, indicated that secondary oxidative stress may be a common component of severe physical stress. Here we tested the individual contributions of the same set of 94 mutants to the development of resistance against exposure to the superoxide-generating agent paraquat and hydrogen peroxide (H(2)O(2)). In fact, 62 mutants displayed significantly decreased survival rates in response to paraquat and/or H(2)O(2) stress compared to the wild type at a confidence level of an α value of ≤ 0.01. Thus, we were able to assign 47 general stress genes to survival against superoxide, 6 genes to protection from H(2)O(2) stress, and 9 genes to the survival against both. Furthermore, we show that a considerable overlap exists between the phenotype clusters previously assumed to be involved in oxidative stress management and the actual group of oxidative-stress-sensitive mutants. Our data provide information that many general stress proteins with still unknown functions are implicated in oxidative stress resistance and further support the notion that different severe physical stress stimuli elicit a common secondary oxidative stress.     

Physically mapping quantitative traits for stress-resistance in the forage grasses

Recent advances in cytogenetics of the Lolium/Festuca complex provide new opportunities for understanding and manipulating physiological mechanisms in complex quantitative traits such as stress resistance. The complex provides a valuable reserve for research and breeding since (a) it includes a wide range of valuable agronomic characters, (b) it has the capacity for intergeneric hybridization with promiscuous recombination, and its genomes, despite their close homology, have sufficient structural heterogeneity to allow Lolium and Festuca chromosomes to be discriminated using genomic in situ hybridization (GISH).Two alternative procedures are used to 'dissect' stress-resistance traits into their individual components both to determine their function and to physically map the relevant QTL(s) onto chromosome arms: (a) Festuca genes are introgessed into Lolium to improve stress resistance, (b) Lolium genes are introgressed into Festuca to reduce stress resistance. Whichever approach is used, alien introgressions can be detected by GISH and assigned to chromosome arms to create a physical map. Genes of interest may then be located more accurately following further recombination events which reduce the size of the relevant alien introgression.It has become obvious during the past years that genetic and physical maps are not directly comparable as chiasmata are not evenly distributed along the chromosome axis. By integrating physical maps created by GISH and genetic linkage-maps, the precise site of genes on a chromosome arm may be determined, and markers found which are tightly linked to the genes of interests, for future use in breeding programmes.Key words: Genomic in situ hybridization (GISH), physical mapping, Lolium/Festuca complex, stress resistance.      

The Mechanical Basis Of Stone Flaking: Problems And Prospects

Abstract

A variety of quite different theories and models concerning the fracture of solids and the behavior of solids under stress have been developed by physical scientists. On the basis of their work, 19 variables are identified that are likely to be important in studying the mechanics of stone flaking. These variables fall into three classes: (1) properties of the material being fractured; (2) properties of the flaking device; and (3) variables relating to the experimental situation. A lack of knowledge concerning the physical properties of many common stone tool materials seriously hinders the direct application of theories of stress and fracture to practical archaeological problems. However, the work of physical scientists may still suggest approaches to problems in lithic technology and variables which may be worth examining.     

The non-synonymous SNP, R1150W, in SCN9A is not associated with chronic widespread pain susceptibility

Background

Chronic pain conditions are characterized by significant individual variability complicating the identification of pathophysiological markers. Leukocyte telomere length (TL), a measure of cellular aging, is associated with age-related disease onset, psychosocial stress, and health-related functional decline. Psychosocial stress has been associated with the onset of chronic pain and chronic pain is experienced as a physical and psychosocial stressor. However, the utility of TL as a biological marker reflecting the burden of chronic pain and psychosocial stress has not yet been explored.

Findings

The relationship between chronic pain, stress, and TL was analyzed in 36 ethnically diverse, older adults, half of whom reported no chronic pain and the other half had chronic knee osteoarthritis (OA) pain. Subjects completed a physical exam, radiographs, health history, and psychosocial questionnaires. Blood samples were collected and TL was measured by quantitative polymerase chain reaction (qPCR). Four groups were identified characterized by pain status and the Perceived Stress Scale scores: 1) no pain/low stress, 2) no pain/high stress, chronic pain/low stress, and 4) chronic pain/high stress. TL differed between the pain/stress groups (p = 0.01), controlling for relevant covariates. Specifically, the chronic pain/high stress group had significantly shorter TL compared to the no pain/low stress group. Age was negatively correlated with TL, particularly in the chronic pain/high stress group (p = 0.03).

Conclusions

Although preliminary in nature and based on a modest sample size, these findings indicate that cellular aging may be more pronounced in older adults experiencing high levels of perceived stress and chronic pain.     

Colon cancer cell adhesion in response to Src kinase activation and actin-cytoskeleton by non-laminar shear stress

Malignant cells shed from tumors during surgical resection or spontaneous metastasis experience physical forces such as shear stress and turbulence within the peritoneal cavity during irrigation, laparoscopic air insufflation, or surgical manipulation, and within the venous or lymphatic system. Since physical forces can activate intracellular signals that modulate the biology of various cell types in vitro, we hypothesized that shear stress and turbulence might increase colon cancer cell adhesion to extracellular matrix, potentiating metastatic implantation. Primary human malignant colon cancer cells isolated from resected tumors and SW620 were subjected to shear stress and turbulence by stirring cells in suspension at 600 rpm for 10 min. Shear stress for 10 min increased subsequent SW620 colon cancer cell adhesion by 40.0 +/- 3.0% (n = 3; P < 0.001) and primary cancer cells by 41.0 +/- 3.0% to collagen I when compared to control cells. In vitro kinase assay (1.5 +/- 0.13 fold) and Western analysis (1.34 +/- 0.04 fold) demonstrated a significant increase in Src kinase activity in cells exposed shear stress. Src kinase inhibitors PP1 (0.1 microM), PP2 (20 microM), and actin-cytoskeleton stabilizer phalloidin (10 microM) prevented the shear stress stimulated cell adhesion to collagen I. Furthermore, PP2 inhibited basal (50.0 +/- 2.8%) and prevented shear stress induced src activation but phalloidin pretreatment did not. These results raise the possibility that shear stress and turbulence may stimulate the adhesion of malignant cells shed from colon cancers by a mechanism that requires both actin-cytoskeletal reorganization an independent physical force activation of Src kinase. Blocking this pathway might reduce tumor metastasis during surgical resection.     

Zonation of shrubs in western Atlantic salt marshes

We explored the generality of the processes mediating shrub zonation in western Atlantic salt marshes by comparing the results of our experiments in Georgia, USA with previous studies from Rhode Island, USA. The shrub Borrichia frutescens dominates the terrestrial border of many Georgia salt marshes. Within the shrub zone, physical stress increased at lower elevations, shrubs at lower elevations were stunted, and experimentally reducing physical stress reduced shrub stunting. Below the shrub zone, physical stress increased further, and the grass Spartina alterniflora dominated. Transplant and neighbor-removal experiments indicated that the lower border of the shrub zone was set more by physical stress than by competition, but that the upper border of the grass zone was set primarily by competition with shrubs. Laboratory experiments indicated that S. alterniflora seedlings survived best and shrub seedlings worst in the flooded, salty treatment that mimicked low-marsh conditions. These processes are similar to those maintaining zonation patterns between the shrub Iva frutescens and the rush Juncus gerardi in Rhode Island salt marshes. However, markedly different processes appear to occur further to the north, where woody shrubs are absent from coastal marshes, and further to the south, where woody plants (mangroves) dominate coastal wetlands.     

Residual stress due to curing can initiate damage in porous bone cement: experimental and theoretical evidence

Residual stress due to shrinkage of polymethylmethacrylate bone cement after polymerisation is possibly one factor capable of initiating cracks in the mantle of cemented hip replacements. No relationship between residual stress and observed cracking of cement has yet been demonstrated. To investigate if any relationship exists, a physical model has been developed which allows direct observation of damage in the cement layer on the femoral side of total hip replacement. The model contains medial and lateral cement layers between a bony surface and a metal stem; the tubular nature of the cement mantle is ignored. Five specimens were prepared and examined for cracking using manual tracing of stained cracks, observed by transmission microscopy; cracks were located and measured using image analysis. A mathematical approach for the prediction of residual stress due to shrinkage was developed which uses the thermal history of the material to predict when stress-locking occurs, and estimates subsequent thermal stress. The residual stress distribution of the cement layer in the physical model was then calculated using finite element analysis. Results show maximum tensile stresses normal to the observed crack directions, suggesting a link between residual stress and pre-load cracking. The residual stress predicted depends strongly on the definition of the reference temperature for stress-locking. The highest residual stresses (4-7 MPa) are predicted for shrinkage from maximum temperature; in this case, magnitudes are sufficiently high to initiate cracks when the influence of stress raisers such as pores or interdigitation at the bone/cement interface are taken into account (up to 24 MPa when calculating stress around a pore according to the method of Harrigan and Harris (J. Biomech. 24(11) (1991) 1047-1058). We conclude that the damage accumulation failure scenario begins before weight-bearing due to cracking induced by residual stress around pores or stress raisers.     

The Long-Term Impact of Physical and Emotional Trauma: The Station Nightclub Fire

Background

Survivors of physical and emotional trauma experience enduring occupational, psychological and quality of life impairments. Examining survivors from a large fire provides a unique opportunity to distinguish the impact of physical and emotional trauma on long-term outcomes. The objective is to detail the multi-dimensional long-term effects of a large fire on its survivor population and assess differences in outcomes between survivors with and without physical injury.

Methods and Findings

This is a survey-based cross-sectional study of survivors of The Station fire on February 20, 2003. The relationships between functional outcomes and physical injury were evaluated with multivariate regression models adjusted for pre-injury characteristics and post-injury outcomes. Outcome measures include quality of life (Burn Specific Health Scale–Brief), employment (time off work), post-traumatic stress symptoms (Impact of Event Scale–Revised) and depression symptoms (Beck Depression Inventory). 104 fire survivors completed the survey; 47% experienced a burn injury. There was a 42% to 72% response rate range. Although depression and quality of life were associated with burn injury in univariate analyses (p<0.05), adjusted analyses showed no significant relationship between burn injury and these outcomes (p = 0.91; p = .51). Post-traumatic stress symptoms were not associated with burn injury in the univariate (p = 0.13) or adjusted analyses (p = 0.79). Time off work was the only outcome in which physical injury remained significant in the multivariate analysis (p = 0.03).

Conclusions

Survivors of this large fire experienced significant life disruption, including occupational, psychological and quality of life sequelae. The findings suggest that quality of life, depression and post-traumatic stress outcomes are related to emotional trauma, not physical injury. However, physical injury is correlated with employment outcomes. The long-term impact of this traumatic event underscores the importance of longitudinal and mental health care for trauma survivors, with attention to those with and without physical injuries.