Plasma catecholamines in fasted and sucrose supplemented rats

Rats were food deprived or given a sucrose supplemented diet for 3 days. Resting plasma catecholamine levels measured remotely from undisturbed rats were not altered by either dietary treatment. However, food deprivation did result in decreases in resting mean arterial blood pressure, heart rate, plasma volume and plasma Na+ concentration. After one minute of intermittent footshock food deprived and sucrose fed rats did not differ from controls with respect to blood pressure, heart rate or plasma catecholamine levels but food deprived rats were less active during footshock and had lower levels of plasma glucose immediately after footshock when compared to controls or sucrose fed rats. Food deprivation and dietary sucrose supplementation have been shown to alter norepinephrine (NE) turnover in specific sympathetic target tissues. Our data indicate that these changes in turnover are not reflected by changes in plasma NE. Therefore, NE turnover rates and plasma NE concentration may not be equivalent indices of sympathetic activity.     

Plasma catecholamines in rats: Daily variations in basal levels and increments in response to stress

Chronic tail artery catheters were surgically implanted into male Sprague-Dawley rats to allow for repeated sampling of blood. Animals were housed individually and maintained on a controlled photoperiod (lights on 0600–1800 hours). In the first experiment, blood samples were obtained 2 days after surgery from animals at 0800, 1600, and 2400 hours and again at 0800 hours on the next day. Plasma levels of the sympathetic transmitter norepinephrine (NE) were higher at 2400 hours compared to all other sampling times. In contrast, plasma levels of the adrenal medullary hormone, epinephrine (EPI), were similar across sampling times. In a second experiment, individual rats were transferred to a shock chamber and after 3 minutes received 10 footshocks (2.0 mA, 0.5 sec duration, every 6 sec). Separate groups of rats were stressed in this manner at 0800, 1600, or 2400 hours. Basal and transfer-induced increments in plasma levels of NE and EPI did not vary with time of day. However, footshock-induced increments in plasma levels of EPI were greater at 0800 hours than at 1600 or 2400 hours. Footshock-induced alterations in plasma NE and behavior of rats did not vary with time of day. These results suggest that basal plasma levels of NE are elevated at 2400 hours due to postural changes associated with increased locomotor activity and not to an endogenous circadian rhythm. Furthermore, this effect is consistent within but not across groups of rats. The responsiveness of the adrenal medulla to the intense stress of footshock appears to be greatest in early morning compared to later afternoon and midnight.     

Perceived stress is associated with smaller hippocampal volume in adolescence

Perceived stress has been associated with decreased hippocampal, amygdala, and prefrontal cortex volume, as well as decreased memory and executive functioning performance in adulthood. Parents' perceived stress has been linked to decreased hippocampal volume in young children. However, no studies have investigated the links between self‐perceived stress and brain structure or function in adolescents. Additionally, findings from previous research with younger or older samples are inconsistent, likely in part due to inconsistencies in participants' age range. In this study, we investigated the associations among self‐perceived stress, family socioeconomic factors (family income, parental education), subcortical (hippocampus, amygdala) volumes, prefrontal cortical thickness and surface area, and memory and executive functioning performance in adolescents. One hundred and forty‐three participants (12–20 years old) were administered a cognitive battery, a questionnaire to assess perceived stress, and a structural MRI scan. Higher levels of perceived stress were associated with decreased adolescent hippocampal volume. This study provides empirical evidence of how experience may shape brain development in adolescence—a period of plasticity during which it may be possible to intervene and prevent negative developmental outcomes.     

Mild prenatal stress in rats is associated with enhanced conditioned fear

We tested the hypothesis that prenatal stress would enhance conditioned fear in adult rats. Pregnant Sprague-Dawley rats were stressed by exposure to a novel environment and subcutaneous injection of saline (0.1 ml 0.9% NaCl) at random times daily from Days 14 to 21 of pregnancy. When compared to adult control (CON) male rats from unmanipulated pregnancies, adult prenatally stressed (PS) male rats showed increased freezing behavior in response to acute footshock as well as increased freezing behavior the next day in the same context, without shock delivery. In another experiment, the gestational stressor was examined for elevations in corticosterone and ACTH. At gestational days (G)15, G17, G19 and G21, maternal and fetal plasma was collected. Analysis showed elevations in corticosterone and ACTH in the PS dams when compared to the CON dams. Additionally, increased corticosterone was found in the PS fetuses when compared to the CON fetuses. Finally, some CON and PS litters were examined for alterations in length of gestation, number of pups born, bodyweight on postnatal day (P)1 and anogenital distance on P1 and differences were not found. In conclusion, our data demonstrate that a mild stressor during gestation, sufficient to raise plasma corticosterone and ACTH, is associated with enhanced conditioned fear during adulthood.     

Forced expiratory volume is associated with cardiovascular and cortisol reactions to acute psychological stress

It has been argued that blunted cardiovascular and cortisol reactions to acute psychological stress reflect a dysregulation of the neural system that supports motivation. We examined the association between forced expiratory volume in 1 s, an effort (hence motivation) dependent measure of lung function measured by spirometry, and cardiovascular and cortisol reactions to a battery of standard psychological stress tasks, assessed 7 years later. Irrespective of how it was expressed, low forced expiratory volume was associated with blunted heart rate and cortisol stress reactivity. The association survived adjustment for smoking, a range of anthropometric and sociodemographic covariates, and commitment to the stress tasks, as well as cognitive ability.     

Impaired hemodynamic response to mental stress in subjects with prehypertension is improved after a single bout of maximal dynamic exercise

INTRODUCTION:

High blood pressure during mental stress in subjects with prehypertension is associated with blunted vasodilation in skeletal muscles, which might be improved by an acute bout of exercise.

OBJECTIVE:

To investigate the hemodynamic responses to mental stress before and after a bout of exercise in subjects with prehypertension.

METHOD:

Eighteen subjects with prehypertension and 16 with normotension underwent a mental stress test before and after a maximal cardiopulmonary exercise test on a treadmill. Blood pressure was measured by auscultation, and forearm blood flow was measured by venous occlusion plethysmography; from these measurements, the vascular conductance was calculated.

RESULTS:

Subjects with prehypertension had a higher mean blood pressure during mental stress (prehypertension 112±2 vs. normotension 101±3 mm Hg, p<0.05), and their vascular conductance did not increase (baseline 0.025±0.004 vs. mental stress 0.022±0.003 a.u., p>0.05). After the exercise bout, the mean blood pressure during mental stress was lower in subjects with prehypertension (before exercise 112±2 vs. after exercise 107±2 mm Hg, p<0.05), and vascular conductance increased (baseline 0.011±0.001 vs. mental stress 0.024±0.004 a.u., p<0.05).

CONCLUSION:

Subjects with prehypertension had elevated blood pressure and a blunted vasodilator response during mental stress, but their blood pressure was attenuated and their vasodilator response was normalized after a single bout of maximal dynamic exercise.     

Soluble E-cadherin is associated with oxidative stress in patients with chronic HBV infection

Mounting evidence indicates that serum soluble E-cadherin (sE-cadherin) serves as an important player in various physiological and pathological processes. However, the crosstalk between serum sE-cadherin and oxidative stress in chronic hepatitis B (CHB) remains to be illustrated. The main purpose of this study is to explore the molecular mechanisms underlying the function of sE-cadherin in CHB virus infection. Levels of serum sE-cadherin, total antioxidant capacity (TAC), glutathione (GSH), superoxide dismutase (SOD), total oxidant activity (TOA), NADPH oxidase 2 (NOX2), and malondialdehyde (MDA), from 51 patients with hepatitis B envelope antigen (HBeAg)-negative CHB, 54 patients with HBeAg-positive CHB, and 109 healthy individuals were detected by enzyme-linked immunosorbent assay. In our study, patients with CHB showed significantly higher serum sE-cadherin levels than healthy individuals (P < .01). Furthermore, we also found that the serum sE-cadherin levels were significantly negatively correlated with TAC, antioxidant enzymes (GSH and SOD) in patients with CHB, and that serum sE-cadherin concentrations were significantly positively correlated with liver enzyme markers (alanine transaminase and aspartate aminotransferase) and oxidative markers (TOA, NOX2, and MDA) in patients with CHB. Therefore, serum sE-cadherin may act as a new candidate biomarker for reflecting inflammation and oxidative stress status in the development and progression of hepatitis B virus infection.     

Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = ?.009, SE = .005, p = .09) and diastolic (B = ?.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = ?.007, SE = .003, p = .03) and impaired vagal tone (B = ?.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.     

High perceived stress in relation to life events is associated with blunted cardiac reactivity

The current study examined whether the perception of life stress related to cardiovascular reactivity. Participants (n = 100) completed the Perceived Stress Scale, the Undergraduate Stress Questionnaire, and undertook a standard mental arithmetic stress task. Blood pressure and pulse rate were measured at baseline, during, and following stress task exposure. Reactivity was the difference between stress and baseline cardiovascular activity. A perceived stress difference score (PSDS) was calculated by subtracting the Undergraduate Stress Questionnaire scores from the Perceived Stress Scale scores. Two groups were created: high PSDS (n = 15; PSDS at least 1 SD above the mean) and low PSDS (n = 15; PSDS at least 1 SD below the mean). There was a significant difference between groups in pulse rate reactivity, F(1,28) = 8.73, p = .006, η² = .24. High PSDS scores were associated with significantly lower pulse rate reactions to stress. Those who perceived their lives as more stressful than their actual stress exposures justified would appear to be characterised by blunted cardiac reactivity.     

Prolonged marital stress is associated with short‐lived responses to positive stimuli

Marital stress is associated with a higher incidence of psychiatric disorders, in particular major depression. One pathway through which marital stress may impact emotional health is by compromising emotion‐responding processes. We examined a longitudinal sample of adults (N = 116; 59 males; 39–84 years) to verify how marital stress predicts reactivity to, and recovery from, emotional provocation. Individuals watched positive, neutral, and negative pictures while an objective measure of affective state, corrugator supercilii muscle activity, was recorded continuously. Our results indicate that marital stress is associated with short‐lived responses to positive pictures, indexed by a less persistent decrease in corrugator activity after picture offset. Extending beyond the prior focus on negative emotional processes, these results suggest that social stress may impact health by influencing the time course of responding to positive events.     

Oxidative stress is associated with atopic indices in relation to childhood rhinitis and asthma

BackgroundThe association between oxidative stress and atopic diseases is uncertain. Several risk factors for atopic diseases have been identified, however, a comprehensive investigation of the relationship between oxidative stress markers and atopic indices related to atopic diseases is currently lacking.MethodsWe investigated 132 children who completed a 7-years follow-up in a birth cohort. Oxidative stress markers including plasma glutathione peroxidase (GPx), myeloperoxidase (MPO), total anti-oxidant capacity (TAC), and urine 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels were measured. Allergen-specific IgE levels, FeNO levels, and pulmonary function tests were also obtained.ResultsThe activity of GPx and levels of MPO were inversely correlated to food (shrimp and crab) and house dust mite sensitization respectively. The 8-OHdG levels were strongly negatively correlated with FeNO levels (p < 0.01). A significant positive correlation was found between TAC levels and pre-and post-bronchodilator FVC % and FEV1% predicted (p < 0.05). All oxidative stress markers were not associated with the risk of atopic diseases. However, GPx-related crab sensitization and 8-OHdG related FeNO levels were significantly associated with increased risk of allergic rhinitis, while MPO-related mite sensitization and TAC-related pulmonary function parameters were strongly associated with risk of asthma (p < 0.01).ConclusionOxidative stress is strongly correlated with allergic indices, potentially playing a role in the modulation of allergic responses contributing to atopic diseases.     

Neuropeptide S receptor gene is associated with cortisol responses to social stress in humans

The neuropeptide S (NPS) and its receptor NPSR represent a transmitter system critically involved in the modulation of anxiety and arousal in rodents. Initial human studies indicate that the T-allele of the functional NPSR gene (NPSR1) polymorphism (rs324981), which increases NPS potency at NPSR, is associated with anxiety-related phenotypes. Since stress is critically involved in the pathogenesis of anxiety disorders, we tested the association between rs324981 and stress reactivity in 196 healthy males. Participants were exposed to the Trier Social Stress Test for Groups (TSST-G), a standardized laboratory protocol for stress exposure in a group format. Salivary cortisol and subjective stress responses were assessed. A significant genotype by time interaction and a main effect of genotype were shown, with T-allele carriers displaying larger cortisol and subjective stress responses. This is the first report to show involvement of the NPS system in the regulation of the neuroendocrine stress response in humans.     

Exercise-induced shear stress is associated with changes in plasma von Willebrand factor in older humans

Shear stress is the frictional force of blood against the endothelium, a stimulus for endothelial activation and the release of von Willebrand factor (vWF). This study tested the hypothesis that the increase in shear stress associated with exercise correlates with plasma vWF. Young (n = 14, 25.7 ± 5.4 years) and older (n = 13, 65.6 ± 10.7 years) individuals participated in 30 min of dynamic handgrip exercise at a moderate intensity. Brachial artery diameter and blood flow were measured using ultrasound Doppler and blood samples were collected before, immediately after, and following 30 min of recovery from exercise with plasma levels of vWF. Plasma levels of vWF increased (P < 0.05) by 6 ± 2% in young individuals and 4 ± 1% in older individuals immediately after exercise. The change in plasma vWF was linearly correlated with the increase in shear stress during exercise in older individuals (post-exercise: r = 0.78, 30 min recovery: r = 0.77, P < 0.01), but no association was found in the young individuals. These changes in plasma levels of vWF in humans suggest that aging influences endothelial activation and hemostasis.     

Type D personality is associated with low cardiovascular reactivity to acute mental stress in heart failure patients

Background

The distressed (Type D) personality is associated with adverse coronary heart disease outcomes, but the mechanisms accounting for this association remain to be elucidated. We examined whether myocardial and hemodynamic responses to mental stress are disrupted in Type D patients with chronic heart failure (HF).

Methods

Ninety-nine HF patients (mean age 65 ± 12 years; 75% men) underwent a public speech task, during which heart rate (HR) and blood pressure (BP) were recorded. Type D personality and its components negative affectivity (NA) and social inhibition (SI) were assessed with the DS14. General linear models with repeated measures and logistic regression were used to assess differences in stress response and recovery.

Results

Type D personality was associated with a reduced HR response (F_1,93 = 4.31, p < .05) independent of the use of beta adrenergic blocking agents and the presence of atrial fibrillation. There were no differences between HF patients with and without a Type D personality with respect to the BP response. Examining continuous NA and SI scores and their interaction (NA ∗ SI), revealed a significant association of NA ∗ SI with the SBP response (F_1,93 = 4.11, p < .05), independent of BP covariates. Results with respect to HR and DBP responses were comparable to the findings using the dichotomous Type D measure. No significant associations between Type D and recovery patterns were found.

Conclusion

HF patients with Type D personality may show an inadequate response to acute social stress, characterized by a blunted HR response.     

Low forced expiratory volume is associated with blunted cardiac reactions to acute psychological stress in a community sample of middle-aged men and women

It has been argued recently that blunted cardiovascular reactions to acute psychological stress have adverse behavioural and health corollaries that reflect dysregulation of the neural systems that support motivation. We examined the association between cardiovascular reactions to a standard stress task, the paced auditory serial arithmetic rest, and forced expiratory volume in one second, an effort, hence motivation, dependent assessment of lung function measured by spirometry. Low forced expiratory volume, expressed as a ratio to height squared was associated with blunted heart rate, but not blood pressure, stress reactivity, r = .17, p < .001. The association survived adjustment for smoking, a range of anthropometric and sociodemographic covariates, resting heart rate and stress task performance, β = .11, p = .005. As such, our results provide support for the hypothesis that blunted stress reactivity may be a peripheral marker of a dysfunction in the brain systems that support motivated behaviour.     

慢性束缚应激致大鼠持续性高血糖症与孤束核损伤有关

目的 探讨孤束核联合亚核前部（acNTS）损伤在慢性束缚应激（CRS）所致的胰岛素抵抗性高血糖症发生中的作用。 方法 采用CRS大鼠模型（n=20;7 d束缚+3 d自由活动，共40 d），检测葡萄糖代谢相关指标。 结果 CRS导致约1/3的个体（n=7）持续性的中度胰岛素抵抗性高血糖（空腹血糖不超过11 mmol/L）。CRS高血糖鼠acNTS可观察到神经元染色浓缩，Caspase-3表达和TUNEL阳性染色，提示出现神经元凋亡样改变。机械损伤acNTS（n=6），空腹血糖水平逐渐升高，也能导致胰岛素抵抗性高血糖, 且高胰岛素血症、胰岛平均体积增大和血清皮质酮水平不变等特点与CRS小鼠一致。 结论 CRS损伤了acNTS的葡萄糖敏感神经元，从而使血糖调节紊乱。     

Posttraumatic stress disorder is associated with attenuated baroreceptor sensitivity among female, but not male, smokers

BACKGROUND: The relationship between posttraumatic stress disorder (PTSD) and parasympathetic nervous system (PNS) functioning was investigated using baroreflex sensitivity (BRS). We hypothesized that individuals with PTSD would exhibit lower BRS than those without PTSD. METHODS: Participants were 80 PTSD patients and 50 controls aged 18-68 years. All participants were smokers, many were veterans (55%), and 60 were women. Beat-to-beat BP was collected during a 5-min baseline rest periods from which estimates of BRS were derived using the sequence method. RESULTS: Women with PTSD exhibited lower BRS (M = 10.5, S.D. = 5.1) than women without PTSD (M = 14.6, S.D. = 10.7). For men, PTSD diagnosis was not associated with BRS, p > .05. CONCLUSIONS: Among women, PTSD was associated with reduced PNS functioning. Men with PTSD did not have attenuated BRS, which may be due to sample characteristics, such as age and combat veteran status. Reduced PNS activity may predispose women with PTSD to poorer cardiovascular health.     

Influenza A virus induction of oxidative stress and MMP-9 is associated with severe lung pathology in a mouse model

Infection by different strains of influenza virus presents different pictures. Whether the pathogenicity of influenza virus is defined by the ability of the virus to induce differential immunopathlogical responses in the lungs still remains unclear. We compared the immunopathological response induced by influenza virus A/WSN/33 (H1N1) and that by A/Panama-like (H3N2) virus in C57BL/6 mice. WSN virus, in contrast to Panama-like virus, induced high mortality and severe lung pathology accompanied by massive Gr-1⁺ and CD11b⁺ cell infiltration and high levels of CXCL6/GCP-2, CCL2/MCP-1 and TIMP-1 production. Infection by WSN virus but not by Panama-like virus induced up-regulation of the active and latent forms of MMP-9 in the lungs and MMP-2/9 inhibitor partially reduced WSN virus-induced lung pathology. Both Gr-1⁺ and CD11b⁺ cells in WSN virus-infected lungs produced reactive oxygen and nitrogen species (ROS/RNS). While wild type mice infected by WSN virus had severe lung pathology and the presence of oxidized phospholipids and numerous MMP-9⁺ cells in the lungs, ncf1 deficiency ablated their expression and manifested less lung pathology. Employing a pulmonary mouse model we demonstrated in this study that infection by virulent influenza virus is characterized by a heavy cellular infiltration, severe lung pathology which is accompanied by oxidative stress and MMP-9 production.     

女性压力性尿失禁经TVT术并发症(附8例报告)

目的提高对经阴道中段吊带（TVT）术并发症的诊断及处理能力。方法选取2002年5月～2006年8月进行的66例TVT术出现并发症8例．包括膀胱穿孔2例、阴道出血1例、膀胱结石2例、排尿困难2例和阴道前壁侵蚀感染1例。对其临床症状、体征、诊断及处理进行分析。结果对并发症处理后的所有病例随访6个月，结果满意，无排尿困难及尿痛等症状的复发。结论认识TVT术相关并发症的表现可提高诊断和处理TVT并发症的能力。