Acute cadmium chloride administration induces hepatic and renal CYP2A5 mRNA, protein and activity in the mouse: involvement of transcription factor NRF2

Modulation of the cytochrome P450 (CYP) monooxygenase system by cadmium was investigated in male, adult DBA/2J mice treated with a single dose (16 mumol/kg body weight, i.p.) of cadmium chloride (CdCl2). Total CYP content of liver and kidney microsomes decreased maximally (56% and 85%, respectively) 24 and 18 h, respectively, after CdCl2 treatment. Progressive increases of hepatic coumarin 7-hydroxylase (COH) activity; indicative of CYP2A5 activity, relative to the total CYP content were seen at 8 h (2-fold), 12 h (3-fold), 18 h (12-fold), and 24 h (15-fold). Similar changes were seen in the kidney. Liver and kidney CYP2A5 mRNA levels increased maximally 12 and 4 h after treatment and decreased to almost half 6 h later. In contrast, kidney and liver CYP2A5 protein levels increased maximally at 18 and 24 h. The CYP2A5 mRNA levels in the kidney and liver increased after Cd treatment in Nrf2 +/+ but not in Nrf2 -/- mouse. This study demonstrates that hepatic and kidney CYP2A5 is upregulated by cadmium with a somewhat faster response in the kidney than the liver. The strong upregulation of the CYP2A5 both at mRNA and enzyme activity levels, with a simultaneous decrease in the total CYP concentration suggest an unusual mode of regulation of CYP2A5 in response to cadmium exposure, amongst the CYP enzymes. The observed decrease in the mRNA but not in protein levels after maximal induction may suggest involvement of post-trancriptional mechanisms in the regulation. Upregulation of CYP2A5 by cadmium in the Nrf2 +/+ mice but not in the Nrf2 -/- mice indicates a role for this transcription factor in the regulation. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

Physiological responses to water stress in Eucalyptus cloeziana and E-argophloia seedlings

Effects of water stress duration and intensity on gas exchange and leaf water potential were investigated in 7-month-old seedlings of a humid coastal provenance (Gympie) and a dry inland (Hungry Hills) provenance of E. cloeziana F. Muell. and in a dry inland (Chinchilla) provenance of E. argophloia Blakely supplied with 100% (T-100), 70% (T-70), 50% (T-50) of their water requirements, or were watered only after they were wilted at dawn (T-0). Seedlings of E. argophloia had the highest midday net photosynthetic rate (A), stomata] conductance (g(s)), stomatal density and predawn leaf water potential (Psi(pd)) in all treatments. The E. cloeziana provenances did not differ in these attributes. The T-70 and T-50 treatments caused reductions in A of 30% in E. argophloia, and 55% in the E. cloeziana provenances. Under the T-0 treatment, E. argophloia maintained higher rates of gas exchange at all levels of water stress than E. cloeziana provenances. The estimates of Psi(pd) and midday water potential (Psi(md)) at which plants remained wilted overnight were respectively: -2.7 and -4.1 MPa for E. cloeziana (humid), -2.8 and -4.0 MPa for E. cloeziana (dry) and, -3.7 and -4.9 MPa for E. argophloia. Following stress relief, both A and g(s) recovered more quickly in E. argophloia and in the dry provenance of E. cloeziana than in the humid provenance. We conclude that E. argophloia is more drought tolerant and has a potential for cultivation in the humid and semi humid climates, whilst E. cloeziana has greater potential in the humid subtropical climates.

The gambling related cognitions scale (GRCS): development, confirmatory factor validation and psychometric properties

Aims The aims of this study are to develop and validate a measure to screen for a range of gambling-related cognitions (GRC) in gamblers. Design and participants A total of 968 volunteers were recruited from a community-based population. They were divided randomly into two groups. Principal axis factoring with varimax rotation was performed on group one and confirmatory factor analysis (CFA) was used on group two to confirm the best-fitted solution. Measurements The Gambling Related Cognition Scale (GRCS) was developed for this study and the South Oaks Gambling Screen (SOGS), the Motivation Towards Gambling Scale (MTGS) and the Depression Anxiety Stress Scale (DASS-2 1) were used for validation. Findings Exploratory factor analysis performed using half the sample indicated five factors, which included interpretative control/bias (GRCS-IB), illusion of control (GRCS-IC), predictive control (GRCS-PC), gambling-related expectancies (GRCS-GE) and a perceived inability to stop gambling (GRCS-IS). These accounted for 70% of the total variance. Using the other half of the sample, CFA confirmed that the five-factor solution fitted the data most effectively. Cronbach's alpha coefficients for the factors ranged from 0.77 to 0.91, and 0.93 for the overall scale. Conclusions This paper demonstrated that the 23-item GRCS has good psychometric properties and thus is a useful instrument for identifying GRC among non-clinical gamblers. It provides the first step towards devising/adapting similar tools for problem gamblers as well as developing more specialized instruments to assess particular domains of GRC.

Role of catecholaminergic inputs to the medial prefrontal cortex in local and subcortical expression of Fos after psychological stress

A wide variety of stressors elicit Fos expression in the medial prefrontal cortex (mPFC). No direct attempts, however, have been made to determine the role of the inputs that drive this response. We examined the effects of lesions of mPFC catecholamine terminals on local expression of Fos after exposure to air puff, a stimulus that in the rat acts as an acute psychological stressor. We also examined the effects of these lesions on Fos expression in a variety of subcortical neuronal populations implicated in the control of adrenocortical activation, one classic hallmark of the stress response. Lesions of the mPFC that were restricted to dopaminergic terminals significantly reduced numbers of Fos-immunoreactive (Fos-IR) cells seen in the mPFC after air puff, but had no significant effect on stress-induced Fos expression in the subcortical structures examined. Lesions of the mPFC that affected both dopaminergic and noradrenergic terminals also reduced numbers of Fos-IR cells observed in the mPFC after air puff. Additionally, these lesions resulted in a significant reduction in stress-induced Fos-IR in the ventral bed nucleus of the stria terminalis. These results demonstrate a role for catecholaminergic inputs to the mPFC, in the generation of both local and subcortical responses to psychological stress. (C) 2004 Wiley-Liss, Inc.

Repressor- and activator-type ethylene response factors functioning in jasmonate signaling and disease resistance identified via a genome-wide screen of Arabidopsis transcription factor gene expression

To identify transcription factors (TFs) involved in jasmonate (JA) signaling and plant defense, we screened 1,534 Arabidopsis (Arabidopsis thaliana) TFs by real-time quantitative reverse transcription-PCR for their altered transcript at 6 h following either methyl JA treatment or inoculation with the incompatible pathogen Alternaria brassicicola. We identified 134 TFs that showed a significant change in expression, including many APETALA2/ethylene response factor (AP2/ERF), MYB, WRKY, and NACTF genes with unknown functions. Twenty TF genes were induced by both the pathogen and methyl JA and these included 10 members of the AP2/ERF TF family, primarily from the B1a and B3 subclusters. Functional analysis of the B1a TF AtERF4 revealed that AtERF4 acts as a novel negative regulator of JA-responsive defense gene expression and resistance to the necrotrophic fungal pathogen Fusarium oxysporum and antagonizes JA inhibition of root elongation. In contrast, functional analysis of the B3 TF AtERF2 showed that AtERF2 is a positive regulator of JA-responsive defense genes and resistance to F. oxysporum and enhances JA inhibition of root elongation. Our results suggest that plants coordinately express multiple repressor-and activator-type AP2/ERFs during pathogen challenge to modulate defense gene expression and disease resistance.

NmlR of Neisseria gonorrhoeae: a novel redox responsive transcription factor from the MerR family

A MerR-like regulator (NmlR -Neisseria merR-like Regulator) identified in the Neisseria gonorrhoeae genome lacks the conserved cysteines known to bind metal ions in characterized proteins of this family. Phylogenetic analysis indicates that NmlR defines a subfamily of MerR-like transcription factors with a distinctive pattern of conserved cysteines within their primary structure. NmlR regulates itself and three other genes in N. gonorrhoeae encoding a glutathione-dependent dehydrogenase (AdhC), a CPx-type ATPase (CopA) and a thioredoxin reductase (TrxB). An nmlR mutant lacked the ability to survive oxidative stress induced by diamide and cumene hydroperoxide. It also had > 50-fold lower NADH-S-nitrosoglutathione oxidoreductase activity consistent with a role for AdhC in protection against nitric oxide stress. The upstream sequences of the NmlR regulated genes contained typical MerR-like operator/promoter arrangements consisting of a dyad symmetry located between the -35 and -10 elements of the target genes. The NmlR target operator/promoters were cloned into a beta-galactosidase reporter system and promoter activity was repressed by the introduction of NmlR in trans. Promoter activity was activated by NmlR in the presence of diamide. Under metal depleted conditions NmlR did not repress P-AdhC (or P-CopA) promoter activity, but this was reversed in the presence of Zn(II), indicating repression was Zn(II)-dependent. Analysis of mutated promoters lacking the dyad symmetry revealed constitutive promoter activity which was independent of NmlR. Gel shift assays further confirmed that NmlR bound to the target promoters possessing the dyad symmetry. Site-directed mutagenesis of the four NmlR cysteine residues revealed that they were essential for activation of gene expression by NmlR.

Impact of acute weight loss and/or thermal stress on rowing ergometer performance

Purpose: The impact of acute weight loss on rowing performance was assessed when generous nutrient intake was provided in 2 h of recovery after making weight. Methods: Competitive rowers (N = 17) completed four ergometer trials, each separated by 48 h. Two trials were performed after a 4% body mass loss in the previous 24 h (WT) and two were performed after no weight restrictions, that is, unrestricted (UNR). In addition, two trials (I X WT, I X UNR) were in a thermoneutral environment (NEUTRAL, mean 21.1 +/- SD 0.7 degrees C, 29.0 +/- 4.5% RH) and two were in the heat (HOT 32.4, +/- 0.4 degrees C, 60.4 +/- 2.7% RH). Trials were performed in a counterbalanced fashion according to a Latin square design. Aggressive nutritional recovery strategies (WT 2.3 g(.)kg(-11) carbohydrate, 34 mg-kg(-1) Na, 28.4 mL(.)kg(-1) fluid; UNR ad libitum) were employed in the 2 h after weigh-in. Results: Both WT (mean 2.1, 95% CI 0.7-3.4 s; P = 0.003) and HOT (4.1, 2.7 - 5.4 s; P < 0.001) compromised 2000-m time-trial performance. Whereas WT resulted in hypohydration, the associated reduction in plasma volume explained only part of the performance compromise observed (0.2 s for every 1% decrement) Moreover, WT did not influence core temperature or indices of cardiovascular function. Conclusions: Acute weight loss compromised performance, despite generous nutrient intake in recovery, although the effect was small. Performance decrements were further exacerbated when exercise was performed in the heat.

Leukocyte subset responses during exercise under heat stress with carbohydrate or water intake

Purpose: This study investigated leukocyte subset responses to moderate-intensity exercise under heat stress, with water (W) or carbohydrate (CHO) drink ingestion. Methods: In repeated trials, 13 soldiers consumed either a W or CHO drink during 3 h of walking at 4.4 km center dot h(-1) with a 5% gradient (15 min rest per hour) under heat stress (35 C and 55% relative humidity). The soldiers wore combat uniforms and carried water bottles and dummy rifles and ammunition, altogether weighing about 11.5 +/- 1.0 kg. Results: Plasma glucose concentration was significantly higher with CHO than W ingestion during exercise (p < 0.01). There were no significant differences between W and CHO conditions in exercise performance, plasma cortisol concentration, heart rate, or core temperature. CHO ingestion significantly moderated the increases in leukocyte (83% in W, 28% in CHO; p < 0.001), monocyte (60% in W, 34% in CHO; p < 0.05), and granulocyte counts (120% in W, 30% in CHO; p < 0.001), but not in lymphocyte count (41% in W, 25% in CHO). Conclusions: The increases in leukocyte and subset counts during moderate-intensity exercise under heat stress may be comparable to those observed during intense exercise in cool conditions. The response of immune cell counts is blunted by CHO intake during moderate-intensity exercise in the heat, and may not occur through the cortisol pathway.

Steatosis: Co-factor in other liver diseases

The prevalence of fatty liver is rising in association with the global increase in obesity and type 2 diabetes. In the past, simple steatosis was regarded as benign, but the presence of another liver disease may provide a synergistic combination of steatosis, cellular adaptation, and oxidative damage that aggravates liver injury. In this review, a major focus is on the role of steatosis as a co-factor in chronic hepatitis C (HCV), where the mechanisms promoting fibrosis and the effect of weight reduction in minimizing liver injury have been most widely studied. Steatosis, obesity, and associated metabolic factors may also modulate the response to alcohol- and drug-induced liver disease and may be risk factors for the development of hepatocellular cancer. The pathogenesis of injury in obesity-related fatty liver disease involves a number of pathways, which are currently under investigation. Enhanced oxidative stress, increased susceptibility to apoptosis, and a dysregulated response to cellular injury have been implicated, and other components of the metabolic syndrome such as hyperinsulinernia and hyperglycemia are likely to have a role. Fibrosis also may be increased as a by-product of altered hepatocyte regeneration and activation of bipotential hepatic progenitor cells. In conclusion, active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis.

The relationship of adult attachment to emotion, catastrophizing, control, threshold and tolerance, in experimentally-induced pain

Although insecure attachment has been associated with a range of variables linked with problematic adjustment to chronic pain, the causal direction of these relationships remains unclear. Adult attachment style is, theoretically, developmentally antecedent to cognitions, emotions and behaviours (and might therefore be expected to contribute to maladjustment). It can also be argued, however, that the experience of chronic pain increases attachment insecurity. This project examined this issue by determining associations between adult attachment characteristics, collected prior to an acute (coldpressor) pain experience, and a range of emotional, cognitive, pain tolerance, intensity and threshold variables collected during and after the coldpressor task. A convenience sample of 58 participants with no history of chronic pain was recruited. Results demonstrated that attachment anxiety was associated with lower pain thresholds; more stress, depression, and catastrophizing; diminished perceptions of control over pain; and diminished ability to decrease pain. Conversely, secure attachment was linked with lower levels of depression and catastrophizing, and more control over pain. Of particular interest were findings that attachment style moderated the effects of pain intensity on the tendency to catastrophize, such that insecurely attached individuals were more likely to catastrophize when reporting high pain intensity. This is the first study to link attachment with perceptions of pain in a pain-free sample. These findings cast anxious attachment as a vulnerability factor for chronic pain following acute episodes of pain, while secure attachment may provide more resilience. (c) 2006 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Plasma cytokine changes in relation to exercise intensity and muscle damage

The purpose of this study was to compare the effects of exercise intensity and exercise-induced muscle damage on changes in anti-inflammatory cytokines and other inflammatory mediators. Nine well-trained male runners completed three different exercise trials on separate occasions: ( 1) level treadmill running at 60% VO2max (moderate-intensity trial) for 60 min; (2) level treadmill running at 85% VO2max (high-intensity trial) for 60 min; (3) downhill treadmill running ( - 10% gradient) at 60% VO2 max (downhill running trial) for 45 min. Blood was sampled before, immediately after and 1 h after exercise. Plasma was analyzed for interleukin-1 receptor antagonist (IL-1ra), IL-4, IL-5, IL-10, IL-12p40, IL-13, monocyte chemotactic protein-1 (MCP-1), prostaglandin E-2, leukotriene B-4 and heat shock protein 70 (HSP70). The plasma concentrations of IL-1ra, IL-12p40, MCP-1 and HSP70 increased significantly (P< 0.05) after all three trials. Plasma prostaglandin E-2 concentration increased significantly after the downhill running and high-intensity trials, while plasma IL-10 concentration increased significantly only after the high-intensity trial. IL-4 and leukotriene B4 did not increase significantly after exercise. Plasma IL-1ra and IL-10 concentrations were significantly higher ( P< 0.05) after the high-intensity trial than after both the moderate-intensity and downhill running trials. Therefore, following exercise up to 1 h duration, exercise intensity appears to have a greater effect on anti-inflammatory cytokine production than exercise-induced muscle damage.

Patterns of neuronal activation in the rat brain and spinal cord in response to increasing durations of restraint stress

By most accounts the psychological stressor restraint produces a distinct pattern of neuronal activation in the brain. However, some evidence is incongruous with this pattern, leading us to propose that the restraint- induced pattern in the central nervous system might depend on the duration of restraint used. We therefore determined the pattern of neuronal activation ( as indicated by the presence of Fos protein) seen in the paraventricular nucleus (PVN), bed nucleus of the stria terminalis, amygdala, locus coeruleus, nucleus tractus solitarius (NTS), ventrolateral medulla (VLM) and thoracic spinal cord of the rat in response to 0, 15, 30 or 60 min periods of restraint. We found that although a number of cell groups displayed a linear increase in activity with increasing durations of restraint ( e. g. hypothalamic corticotrophin-releasing factor (CRF) cells, medial amygdala neurons and sympathetic preganglionic neurons of the thoracic spinal cord), a number of cell groups did not. For example, in the central amygdala restraint produced both a decrease in CRF cell activity and an increase in non-CRF cell activity. In the locus coeruleus, noradrenergic neurons did not display Fos in response to 15 min of restraint, but were significantly activated by 30 or 60 min restraint. After 30 or 60 min restraint a greater degree of activation of more rostral A1 noradrenergic neurons was observed compared with the pattern of A1 noradrenergic neurons in response to 15 min restraint. The results of this study demonstrate that restraint stress duration determines the amount and the pattern of neuronal activation seen in response to this psychological stressor.

Adult attachment, anxiety, and pain self-efficacy as predictors of pain intensity and disability

Pain self-efficacy and anxiety have each been shown to contribute substantially to pain intensity and pain-related disability. Although adult attachment theory has been related separately to chronic pain, anxiety, and self-efficacy, it has not before been investigated with either pain self-efficacy or anxiety in the context of chronic pain. This study investigated the interrelations between these aspects of the chronic pain experience and their relative contributions towards pain intensity and disability. A clinical sample of 152 chronic pain patients participated in this study, completing self-report measures of attachment, self-efficacy, pain intensity, and disability, prior to attending a multidisciplinary pain clinic. Results revealed that fearful and preoccupied (anxious) attachment categories were associated with low pain self-efficacy, while high scores on the attachment dimension of comfort with closeness were linked with high pain self-efficacy, particularly for males. Insecure attachment (whether defined in terms of categories or dimensions) was related to higher levels of anxiety. Pain self-efficacy proved a stronger predictor of pain intensity than did anxiety and was a stronger predictor of disability than pain intensity or anxiety. In addition, comfort with closeness moderated the associations between pain self-efficacy and disability, pain self-efficacy and pain intensity, and anxiety and disability. Together, these findings support the value of adopting an attachment theoretical approach in the context of chronic pain. Treatment considerations and future research directions are considered. (c) 2006 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Effect of training on the response of plasma vascular endothelial growth factor to exercise in patients with peripheral arterial disease

Expansion of the capillary network, or angiogenesis, occurs following endurance training. This process, which is reliant on the presence of VEGF (vascular endothelial growth factor), is an adaptation to a chronic mismatch between oxygen demand and supply. Patients with IC (intermittent claudication) experience pain during exercise associated with an inadequate oxygen delivery to the muscles. Therefore the aims of the present study were to examine the plasma VEGF response to acute exercise, and to establish whether exercise training alters this response in patients with IC. In Part A, blood was collected from patients with IC (n = 18) before and after (+ 20 and + 60 min post-exercise) a maximal walking test to determine the plasma VEGF response to acute exercise. VEGF was present in the plasma of patients (45.11 +/- 29.96 pg/ml) and was unchanged in response to acute exercise. Part B was a training study to determine whether exercise training altered the VEGF response to acute exercise. Patients were randomly assigned to a treatment group (TMT; n = 7) that completed 6 weeks of high-intensity treadmill training, or to a control group (CON; n = 6). All patients completed a maximal walking test before and after the intervention, with blood samples drawn as for Part A. Training had no effect on plasma VEGF at rest or in response to acute exercise, despite a significant increase in maximal walking time in the TMT group (915 + 533 to 1206 + 500 s; P = 0.009) following the intervention. The absence of a change in plasma VEGF may reflect altered VEGF binding at the endothelium, although this cannot be confirmed by the present data.