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PubMed1992

[Dimensions of coping with chronic pain--a replication study].

Clinical-psychological research on pain conceptualizes pain as a transactional process. There, important components are pain-experience, pain control (coping with pain) and subjectively felt pain-related stress. The intent of one preceding study (Geissner, 1991) was to describe, analyze, and validate behavioral and cognitive aspects of pain control and emotional and behavioral aspects of pain-related subjective stress. The purpose of the present study is to replicate the factors of pain-processing, gained by exploratory data-analyses. 162 patients with headache, back pain and joint pain answered the revised version of the set of questionnaires used in the former study. Analyses are done by means of confirmatory factor analysis (LISREL 7 by Jöreskog & Sörbom) and with admission of steps to optimize a solution found. 3 Dimensions of more behavioral aspects of pain control are identified: Mental distraction, relaxation and counteractivities. Also, 3 dimensions of cognitive aspects of pain control are found: Cognitive restructuring, planning skills to deal with the pain, and self-assurance of ones own skills. The dimensions of subjectively felt pain-related stress are (1) helplessness/depression, (2) anxiety, and (3) anger. All dimensions prove to be factorially homogenous and structurally distinct. In regard to the solution found in the preceding study, differences are small. Therefore, it can be said, that the results gained formerly are replicable. Findings from correlational and regression-analytic studies further support the validity of the dimensions of pain-processing.

Adaptation, Psychological↗
PubMed1997

Phenotypic and evolutionary adaptation of a model bacterial system to stressful thermal environments.

We studied both phenotypic and evolutionary adaptation to various thermal environments using the bacterium Escherichia coli as an experimental model system. We determined that 42 degrees C was stressful to a bacterial clone adapted to 37 degrees C, based on reductions in both absolute and competitive fitness, as well as induction of a heat stress response. This clone was also used to found replicated populations that were propagated for thousands of generations under several different thermal regimes, including 42 degrees C. Evolutionary adaptation of the populations to 42 degrees C resulted in an increase in both absolute and relative fitness at that temperature, measured respectively as an increase in the number of descendants (and their biovolume) and in competitive ability relative to the ancestral clone. The replicated experimental lineages achieved their evolutionary improvement by several distinct pathways, which produced differential preadaptation to a non-stressful nutrient environment. Adaptation to this stressful temperature entailed neither a change in the ancestral thermal niche nor any pronounced trade-offs in fitness within the thermal niche, contrary to a priori predictions. This study system was several important advantages for evaluating hypotheses concerning the effects of stress on phenotypic and evolutionary adaptation, including the ability to obtain lineages that have evolved in controlled and defined environments, to make direct measurements of fitness and to quantify the degree of stress imposed by different environments.

Adaptation, Physiological↗
PubMedDate not supplied

[Redox status in HIV+ patients under HAART].

Oxidative stress decreases immune defences and is also suggested to participate in the activation of HIV virus replication. That is why we decided to explore some biomarkers of oxidative stress (reduced glutathione, lipoperoxides, true malondialdehyde and vitamin C) in 20 HIV positive patients whose HIV replication was determined by measurement of RNA viral load. Reduced glutathione is decreased in HIV positive patients, without correlation with the viral load. The patients mean content of lipoperoxides is twice that of controls but with such a large range that there is no statistical difference.

Adult↗
PubMed1975

The role of information in attenuating behavioral responses to stress: a reinterpretation of the misattribution phenomenon.

Two experiments replicating and extending Ross, Rodin, and Zimbardo were conducted to determine whether reductions in emotional behavior resulted from misattribution of naturally occurring arousal states or from informational factors confounded in previous research. In Experiment 1, arousal or arousal-irrelevant symptoms were attributed to noise or the threat of shock. Subjects receiving arousal symptoms avoided shock less, regardless of attribution. Extended manipulation checks revealed no evidence of differential attribution of arousal. In Experiment 2 subjects heard high or low noise. Arousal symptoms were attributed to noise or threat of shock. Subjects for whom arousal symptoms were attributed to noise and who heard low noise spent more time in shock avoidance than the other three groups. Again there was no evidence of misattribution of arousal. The results are interpreted as indicating that the results of misattribution studies are best explained in terms of the presentation of arousal information in a plausible context.

Arousal↗
PubMed2003

A snapshot of the low temperature stress transcriptome of developing rice seedlings (Oryza sativa L.) via ESTs from subtracted cDNA library.

Rice (Oryza sativa L.) is sensitive to chilling particularly during early seedling development. Given the biochemical complexity of tolerance mechanisms, genetic potential for this trait depends on highly coordinated expression of many genes. We used a simple cDNA subtraction strategy to develop Expressed Sequence Tags (ESTs) that represent an important subset of cold stress-upregulated genes. The 3,084 subtracted cDNA clones represent a total of 1,967 unigenes from 1,354 singletons and 613 contigs. As expected in the developing seedlings, genes involved in basic cellular processes, i.e., metabolism, growth and development, protein synthesis, folding and destination, cellular transport, cell division and DNA replication were widely represented. Genes with stress-related and regulatory functions comprised 23.17% of the total ESTs. These categories included proteins with known function in cellular defenses against abiotic (drought, cold and salinity) and biotic (pathogen) stresses, and proteins involved in developmental and stress response signalling and transcription. Based on the types of genes represented, tolerance mechanisms rely on precise integration of developmental processes with stress-related responses. A large fraction of the ESTs (38.7%) represents unknown proteins. This EST library is a rich source of cold stress-related genes, and supplements for other publicly available libraries for comprehensive analysis of the stress-response transcriptome.

Cold Temperature↗
PubMed2002

Clinal variation in Drosophila serrata for stress resistance and body size.

Clines for size and stress resistance traits have been described for several Drosophila species and replicable clines across different species may indicate climatic selection. Here we consider clines in stress resistance traits in an Australian endemic species, D. serrata, by comparing levels of variation within and among isofemale lines initiated with flies collected from the eastern coast of Australia. We also consider clinical variation in chill coma recovery, a trait that has recently been shown to exhibit high levels of variation among Drosophila species. Patterns were compared with those in the cosmopolitan species D. melanogaster from the same area. Both desiccation and starvation resistance showed no clinical pattern despite heritable variation among isofemale lines. In contrast chill coma resistance exhibited a linear cline in the anticipated direction, resistance increasing with latitude. Body size was measured as wing length and body weight. Both traits showed geographic variation and strong non-linear clines with a sharp reduction in size in the tropics. These results are discussed in the context of climatic selection and evolutionary processes limiting species borders.

Animals↗
PubMed2006

A three-dimensional model of differentiation of immortalized human bronchial epithelial cells.

A therapeutic approach being investigated for a variety of pathologies is tissue regeneration using a patient's own cells. Such studies have been hampered due to the difficulty in growing epithelial cells for prolonged periods in culture. Replicative senescence due to short telomeres and p16 induced by culture stress work together to inhibit cell growth. Forced expression of telomerase (hTERT) can prevent replicative senescence, and expression of the cell cycle protein cdk4 can sequester p16, thereby immortalizing epithelial cells in culture. In the present study, we used this method to immortalize human bronchial epithelial cells (HBECs) to determine whether immortalized HBECs retain the ability to differentiate normally. HBECs were plated atop contracted collagen gels containing lung fibroblasts. This three-dimensional (3D) tissue model was cultured initially submerged, then raised to the air/liquid interface for up to 28 days. Normal differentiation was assessed by the presence of ciliated cells, goblet (mucin-producing) cells, and basal epithelial cells. Scanning electron microscopic observations revealed both ciliated and non-ciliated cells in these 3D tissues. Histological examination revealed the presence of mucin-producing cells, and immunohistochemistry using antibodies against p63 and keratin 14 showed the presence of basal cells. These results demonstrate that immortalized HBECs retain the capacity to differentiate into each of three cell types: basal, mucin-producing, and columnar ciliated epithelial cells. Such cells will be useful cellular reagents for research in aging, cancer progression, as well as normal bronchial epithelial differentiation and will help progress the use of engineered cells to enhance tissue regeneration.

Biomarkers↗
PubMed1993

Effect of environmental heat stress on follicular development and steroidogenesis in lactating Holstein cows.

Lactating Holstein cows were utilized over two replicate periods (July and September, 1990) to examine the effect of summer heat stress on follicular growth and steroidogenesis. On day of synchronized ovulations, cows were assigned to shade (n=11) or no shade (n=12) management systems. Follicular development was monitored daily by ultrasonography until ovariectomy on Day 8 post estrus. At time of ovariectomy, dominant and second largest follicles were dissected from the ovary. Aromatase activity and steroid concentrations in dominant and subordinate follicles were measured. Acute heat stress had no effects on patterns of growth of first wave dominant and subordinate follicles between Days 1 and 7 of the cycle. Compared with shaded cows, the heat stressed cows did not have suppression of medium size (6 to 9 mm) follicles between Days 5 and 7. A treatment x follicle interaction was detected (P<0.01) for follicular diameter and fluid volume at Day 8. Dominant follicles in shade were bigger (16.4>14.5 mm) and contained more fluid (1.9>1.1 ml) than dominant follicles in no shade. Conversely, subordinate follicles in no shade were bigger (10.1>7.9 mm) and contained more fluid (0.4>0.2 ml) than subordinate follicles in shade. Concentrations of estradiol in plasma and follicular fluid were higher (P<0.01) in July than in September. Heat stress appears to alter the efficiency of follicular selection and dominance, and to have adverse effects on the quality of ovarian follicles.

Journal Article↗
PubMed2005

Inhibition of the herpes simplex virus type 1 DNA polymerase induces hyperphosphorylation of replication protein A and its accumulation at S-phase-specific sites of DNA damage during infection.

The treatment of mammalian cells with genotoxic substances can trigger DNA damage responses that include the hyperphosphorylation of replication protein A (RPA), a protein that plays key roles in the recognition, signaling, and repair of damaged DNA. We have previously reported that in the presence of a viral polymerase inhibitor, herpes simplex virus type 1 (HSV-1) infection induces the hyperphosphorylation of RPA (D. E. Wilkinson and S. K. Weller, J. Virol. 78:4783-4796, 2004). We initiated the present study to further characterize this genotoxic response to HSV-1 infection. Here we report that infection in the presence of polymerase inhibitors triggers an S-phase-specific response to DNA damage, as demonstrated by induction of the hyperphosphorylation of RPA and its accumulation within viral foci specific to the S phase of the cell cycle. This DNA damage response occurred in the presence of viral polymerase inhibitors and required the HSV-1 polymerase holoenzyme as well as the viral single-stranded-DNA binding protein. Treatment with an inhibitor of the viral helicase-primase did not induce the hyperphosphorylation of RPA or its accumulation in infected cells. Taken together, these results suggest that the S-phase-specific DNA damage response to infection is dependent on the specific inhibition of the polymerase. Finally, RPA hyperphosphorylation was not induced during productive infection, indicating that active viral replication does not trigger this potentially detrimental stress response.

Animals↗
PubMed2003

Kinematic changes after fusion and total replacement of the ankle: part 1: Range of motion.

BACKGROUND: The purpose of this study was to determine how closely the present designs of ankle prostheses mimic the unique requirements of the foot and ankle. The three-dimensional range of motion (ROM) of the ankle joint complex, before and after ankle arthrodesis and after implantation of three currently used total ankle prostheses, was investigated. METHODS: The three-dimensional ROM was determined in six fresh-frozen cadaver leg specimens using a 6-df device with an axial load of 200 N and a four-camera high-speed video system. A moment of 100 Nm was applied to the footplate to determine the ROM in the sagittal (dorsiflexion and plantarflexion) and frontal (inversion and eversion) planes. The same moment was applied to the tibia to determine the ROM for the internal and external tibial rotation. The measurements were performed for the normal ankle, the fused ankle, and the AGILITY, HINTEGRA, and S.T.A.R. prostheses. RESULTS: Compared to the normal condition, the ROM for dorsiflexion and plantarflexion was changed for all surgical interventions. The changes were highest for the ankle arthrodesis. The changes due to the prostheses were significantly less than the changes due to ankle arthrodesis. Compared to the normal condition, the total ROM for inversion/eversion was slightly decreased by the fused ankle and not changed by the three-component prostheses (HINTEGRA, S.T.A.R.). However, the ROM for inversion/eversion was significantly higher for the two-component prosthesis, AGILITY. The ROM for internal and external tibial rotation was not altered by the AGILITY and HINTEGRA ankle, but it was significantly reduced by the ankle arthrodesis. S.T.A.R. showed a significant shift of the total ROM toward internal tibial rotation. CONCLUSIONS: The three tested ankle joint prostheses changed the ROM of the ankle joint complex less than ankle fusion did. Total ankle prostheses were shown to replicate normal joint ROM closely. However, ankle arthrodesis was found to reduce the ROM substantially in all three planes: the sagittal, frontal, and horizontal planes. CLINICAL IMPLICATIONS: With respect to the ROM, total ankle replacement changes the natural ankle joint condition less than ankle arthrodesis, which reduces the ROM in all three planes and might increase stress in adjacent structures. The prosthesis that replicated the normal ankle joint ROM best was the one with the most anatomical design.

Aged↗
PubMed1996

Social desirability in the assessment of trauma.

Since admitting distress is often considered undesirable, the role of social desirability as a moderator variable in the assessment of traumatic events scores, on the PTSD Interview, and diagnosis was investigated. A sample of 342 city bus drivers were grouped by their lifetime exposure to trauma (nonexposed, stressful but nontraumatic event, traumatic event). Analyses replicate and extend findings from the literature on life events: social desirability plays a marginal role as a moderator variable in the assessment of trauma.

Bias↗
PubMed1990

The Inventory of College Students' Recent Life Experiences: a decontaminated hassles scale for a special population.

The development and validation of a new decontaminated hassles measure, the Inventory of College Students' Recent Life Experiences, are described. An initial pool of 85 items was administered to 100 undergraduates along with the Perceived Stress Scale. Forty-nine items were selected based on significant correlations against the Perceived Stress Scale. The alpha reliability of the resultant final form of the Inventory of College Students' Recent Life Experiences and its correlation against the Perceived Stress Scale were both high. In a separate cross-replication sample of 108 undergraduates, the alpha reliability of the Inventory and its correlation against the Perceived Stress Scale showed little shrinkage. Furthermore, separate analyses for male and female subjects supported the reliability and validity of the Inventory of College Students' Recent Life Experiences across gender. Factor analysis of the Inventory yielded seven interpretable factors. Intercorrelations among sub-scales based on these factors were generally modest, though in all cases significant, suggesting that the Inventory is relatively free of contamination by psychological distress.

Adult↗
PubMed2000

Positive torsional strain causes the formation of a four-way junction at replication forks.

The advance of a DNA replication fork requires an unwinding of the parental double helix. This in turn creates a positive superhelical stress, a (+)-DeltaLk, that must be relaxed by topoisomerases for replication to proceed. Surprisingly, partially replicated plasmids with a (+)-DeltaLk were not supercoiled nor were the replicated arms interwound in precatenanes. The electrophoretic mobility of these molecules indicated that they have no net writhe. Instead, the (+)-DeltaLk is absorbed by a regression of the replication fork. As the parental DNA strands re-anneal, the resultant displaced daughter strands base pair to each other to form a four-way junction at the replication fork, which is locally identical to a Holliday junction in recombination. We showed by restriction endonuclease digestion that the junction can form at either the terminus or the origin of replication and we visualized the structure with scanning force microscopy. We discuss possible physiological implications of the junction for stalled replication in vivo.

DNA Replication↗
PubMed2007

Impact of age at first drink on stress-reactive drinking.

BACKGROUND: Although recent data from animal models indicate that adolescent ethanol exposure increases self-administered ethanol intake in adult rats, the impact of age at first drink on the association between stress and drinking has not been studied in humans. METHODS: Data collected in the 2001 to 2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were used to estimate the extent to which age at first drink modified the association between stress and average daily volume (ADV) of ethanol intake in a sample of 26,946 past-year drinkers. Successive models estimated the magnitude and significance of the interaction between age at first drink (ages 14 or younger, 15-17, and 18 or older) and number of stressors (out of 12 past-year negative life events) after (1) adjusting for sociodemographic characteristics, (2) additionally adjusting for family history of alcoholism, comorbid psychopathology, adolescent, and past-year tobacco and illicit drug use, and (3) additionally adjusting for all other significant interactions with number of stressors. RESULTS: Even after adjusting for a wide range of confounders and their interactions with stress, initiation of drinking at ages 14 and younger increased the association between the number of stressors and ADV of ethanol consumption by 8% (p=0.014), when considering the full range of 12 potential stressors. In fact, the positive association between stress and consumption was significant only for this group of drinkers with early adolescent exposure to ethanol. Within this group, ADV of consumption increased by an average of 7% with each additional stressor experienced, although the exact percentage increase varied as a function of other covariates that had significant interactions with stress. When a reduced set of 4 stressors was considered, the magnitudes of the associations were mostly unchanged, but the modifying effect of age at first drink fell short of statistical significance (p=0.309) in the fully adjusted model. CONCLUSIONS: The findings of this study are consistent with the argument that early-onset drinking may increase stress-reactive ethanol consumption; however, these findings need to be replicated in an experimental human study in order to control fully the direction of the relationship between stress and consumption.

Adolescent↗
PubMed2006

Targeted disruption of the mouse ing1 locus results in reduced body size, hypersensitivity to radiation and elevated incidence of lymphomas.

Ing1 belongs to the family of evolutionary conserved genes encoding nuclear PHD finger-containing proteins implicated in a variety of processes, including tumorigenesis, replicative senescence, excision repair and response to genotoxic stress. We have generated mice deficient in all the isoforms of Ing1 by targeted disruption of the exon that is common for all ing1 transcripts. Embryonic fibroblasts from ing1-knockout mice were similar to the wild-type cells in their growth characteristics, replicative lifespan in culture, p53 induction and sensitivity to various cytotoxic treatments with minor alterations in cell cycle distribution in response to genotoxic stress. ing1-deficient animals are characterized by reduced size with no obvious morphological, physiological or behavioral abnormalities, indicating that ing1 function is dispensable for the viability of mice under normal physiological conditions. Loss of ing1 was associated with earlier onset and higher incidence of lymphomas. Consistent with the possible involvement of Ing1 in DNA repair, ing1-deficient mice were more sensitive to total body gamma radiation. Our observations are well in line with the suggested role of ing1 as a candidate tumor suppressor gene involved in control of DNA damage response.

Abnormalities, Multiple↗
PubMed2005

Defective DNA single-strand break repair in spinocerebellar ataxia with axonal neuropathy-1.

Spinocerebellar ataxia with axonal neuropathy-1 (SCAN1) is a neurodegenerative disease that results from mutation of tyrosyl phosphodiesterase 1 (TDP1). In lower eukaryotes, Tdp1 removes topoisomerase 1 (top1) peptide from DNA termini during the repair of double-strand breaks created by collision of replication forks with top1 cleavage complexes in proliferating cells. Although TDP1 most probably fulfils a similar function in human cells, this role is unlikely to account for the clinical phenotype of SCAN1, which is associated with progressive degeneration of post-mitotic neurons. In addition, this role is redundant in lower eukaryotes, and Tdp1 mutations alone confer little phenotype. Moreover, defects in processing or preventing double-strand breaks during DNA replication are most probably associated with increased genetic instability and cancer, phenotypes not observed in SCAN1 (ref. 8). Here we show that in human cells TDP1 is required for repair of chromosomal single-strand breaks arising independently of DNA replication from abortive top1 activity or oxidative stress. We report that TDP1 is sequestered into multi-protein single-strand break repair (SSBR) complexes by direct interaction with DNA ligase IIIalpha and that these complexes are catalytically inactive in SCAN1 cells. These data identify a defect in SSBR in a neurodegenerative disease, and implicate this process in the maintenance of genetic integrity in post-mitotic neurons.

Axons↗
PubMed1999

Immediate increase of portal pressure, reflecting sinusoidal shear stress, induced liver regeneration after partial hepatectomy.

The mechanisms whereby hepatocytes in the normal liver can be primed for replication following partial hepatectomy (PHx) are poorly understood. To determine whether "shear stress," which is induced by acute portal hypertension after PHx, is involved in liver regeneration, we studied liver regeneration in rats with splenic transposition (SPT) in which we can minimize the postoperative elevation of portal pressure. Rats underwent 70% PHx following splenic transposition or sham surgery and were killed at various time points to measure portal pressure and other factors. In the control groups, the portal pressure was significantly increased immediately after surgery, peaking at 48 h, and returning to near the preoperative levels by 168 h after PHx. In the SPT group, although portal pressure increased immediately, it decreased to the control levels 6 h after PHx and thereafter repeatedly increased. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels peaked at 24 and 6 h after PHx, respectively. Proliferative cell analysis was done using MIB-5 antibody, and there were no significant differences between the two groups. Furthermore, liver weight was restored in the same way in both groups. Taken together, the results suggest that an immediate increase in portal pressure is necessary for the initiation of liver regeneration.

Animals↗
PubMed2001

Topoisomerase II can unlink replicating DNA by precatenane removal.

We have analysed the role of topoisomerase II (topo II) in plasmid DNA replication in Xenopus egg extracts, using specific inhibitors and two-dimensional gel electrophoresis of replication products. Topo II is dispensable for nuclear assembly and complete replication of plasmid DNA but is required for plasmid unlinking. Extensive unlinking can occur in the absence of mitosis. Replication intermediates generated in the absence of topo II activity have an increased positive superhelical stress (+DeltaLk), suggesting a deficiency in precatenane removal. The geometry of replication intermediates cut by poisoning topo II with etoposide and purified by virtue of their covalent attachment to topo II subunits demonstrates that topo II acts behind the forks at all stages of elongation. These results provide direct evidence for unlinking replicating DNA by precatenane removal and reveal a division of labour between topo I and topo II in this eukaryotic system. We discuss the role of chromatin structure in driving DNA unlinking during S phase.

Animals↗