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System Activity (system + activity)
Kinds of System Activity Selected AbstractsII. INTERACTIONS AMONG MARITAL CONFLICT, SYMPATHETIC, AND PARASYMPATHETIC NERVOUS SYSTEMS ACTIVITY IN THE PREDICTION OF CHILDREN'S EXTERNALIZING PROBLEMSMONOGRAPHS OF THE SOCIETY FOR RESEARCH IN CHILD DEVELOPMENT, Issue 1 2009Article first published online: 18 MAR 200 First page of article [source] Effect of galactose and glucose on the exopolysaccharide production and the activities of biosynthetic enzymes in Lactobacillus casei CRL 87JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2001F. Mozzi Aims: The objective of this work was to study the influence of the sugar source on exopolysaccharide (EPS) production and the activities of the enzymes involved in the synthesis of sugar nucleotides in Lactobacillus casei CRL 87. The relationship between these enzymes and EPS formation was determined. Methods and Results: The concentration of EPS was estimated by the phenol/sulphuric acid method while the chemical composition of purified EPS was investigated using gas-liquid chromatography. Biosynthetic enzyme activities were determined spectrophotometrically by measuring the formation or disappearance of NAD(P)H at 340 nm. Polysaccharide production by Lb. casei CRL 87 was 1·7 times greater on galactose than on glucose. The isolated polymer was composed of rhamnose, glucose and galactose. The activities of uridine-diphosphate (UDP)-glucose-pyrophosphorylase, thymidine-diphosphate (dTDP)-glucose-pyrophosphorylase and the dTDP-rhamnose-synthetic enzyme system were higher in galactose-grown than in glucose-grown cells. When an EPS, mutant strain was used, galactokinase activity was not detected on galactose, this sugar not being available for the formation of sugar nucleotides for further EPS production. dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities were lower than the values found for the wild type strain. Conclusions: The carbon source present in the culture medium affects EPS production by Lb. casei CRL 87. The greater polymer synthesis by galactose-grown cells is correlated with the higher UDP-glucose-pyrophosphorylase, dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities. Initial sugar metabolism is also an important step for the synthesis of EPS precursors by this strain. Significance and Impact of the Study: Knowledge of the effect of the sugar source on EPS production and the activities of biosynthetic enzymes provides information about the mechanisms of regulation of the synthesis of EPS which can contribute to improving polymer production. [source] Do rural hospitals lag behind urban hospitals in addressing community health needs?AUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 4 2009An analysis of recent trends in US community hospitals Abstract Objective:,This study examined whether rural and urban hospitals differ in their level of responsiveness to community health needs. Design:,This study used a multivariate, longitudinal research design. Research setting:,A cross-sectional survey was the setting for this study. Participants:,The participants were rural or urban hospitals in the United States. Main outcome measures:,The dependent variables were selected from the American Hospital Association hospital survey questions that are related to community health needs. The independent variable was rural or urban location. Results:,Rural hospitals improved more than urban hospitals in addressing community health needs from 1997 through 2006 for most of the indicators, especially in working with other providers to conduct a community health assessment. However, rural hospitals still lag significantly behind urban hospitals in tracking health information. Conclusions:,This study suggests that rural hospitals do not lag behind urban hospitals in addressing community health needs. Further research is needed to understand the role of community hospitals in influencing local health delivery system activities regarding the potential community benefits and their impact on improving health of local populations. [source] Volume natriuresis vs. pressure natriuresisACTA PHYSIOLOGICA, Issue 4 2004P. Bie Abstract Body fluid regulation depends on regulation of renal excretion. This includes a fast vasopressin-mediated water-retaining mechanism, and slower, complex sodium-retaining systems dominated by the renin,angiotensin aldosterone cascade. The sensory mechanisms of sodium control are not identified; effectors may include renal arterial pressure, renal reflexes, extrarenal hormones and other regulatory factors. Since the pioneering work of Guyton more than three decades ago, pressure natriuresis has been in focus. Dissociations between sodium excretion and blood pressure are explained as conditions where regulatory performance exceeds the precision of the measurements. It is inherent to the concept, however, that sudden transition from low to high sodium intake elicits an arterial pressure increase, which is reversed by the pressure natriuresis mechanism. However, such transitions elicit parallel changes in extracellular fluid volume thereby activating volume receptors. Recently we studied the orchestration of sodium homeostasis by chronic and acute sodium loading in normal humans and trained dogs. Small increases in arterial blood pressure are easily generated by acute sodium loading, and dogs appear more sensitive than humans. However, with suitable loading procedures it is possible , also acutely , to augment renal sodium excretion by at least one order of magnitude without any change in arterial pressure whatsoever. Although pressure natriuresis is a powerful mechanism capable of overriding any other controller, it seems possible that it is not operative under normal conditions. Consequently, it is suggested that physiological control of sodium excretion is neurohumoral based on extracellular volume with neural control of renin system activity as an essential component. [source] Mood states, sympathetic activity, and in vivo ,-adrenergic receptor function in a normal populationDEPRESSION AND ANXIETY, Issue 7 2008Bum-Hee Yu M.D. Ph.D. Abstract The purpose of this study was to examine the relationship between mood states and ,-adrenergic receptor function in a normal population. We also examined if sympathetic nervous system activity is related to mood states or ,-adrenergic receptor function. Sixty-two participants aged 25,50 years were enrolled in this study. Mood states were assessed using the Profile of Mood States (POMS). ,-adrenergic receptor function was determined using the chronotropic 25 dose isoproterenol infusion test. Level of sympathetic nervous system activity was estimated from 24-hr urine norepinephrine excretion. Higher tension-anxiety, depression-dejection, and anger-hostility were related to decreased ,-adrenergic receptor sensitivity (i.e., higher chronotropic 25 dose values), but tension-anxiety was the only remaining independent predictor of ,-adrenergic receptor function after controlling for age, gender, ethnicity, and body mass index (BMI). Urinary norepinephrine excretion was unrelated to either mood states or ,-adrenergic receptor function. These findings replicate previous reports that anxiety is related to decreased (i.e., desensitized) ,-adrenergic receptor sensitivity, even after controlling for age, gender, ethnicity, and body mass index. Depression and Anxiety 0:1,6, 2007. © 2007 Wiley-Liss, Inc. [source] Forearm vasoconstrictor response in uncomplicated type 1 diabetes mellitusEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2006P. J. Van Gurp Abstract Background, According to the ,haemodynamic hypothesis', increased tissue perfusion predisposes to microangiopathy in diabetic patients. We hypothesized that the typical haemodynamic changes underlying the increased tissue perfusion can be explained by a decreased sympathetic nerve activity caused by chronic hyperglycaemia. In this study we investigated sympathetic activity in patients with uncomplicated type 1 diabetes mellitus (DM). Materials and methods, In 15 DM patients (DM duration 6·3 ± 3·8 year; HbA1c 7·9 ± 1·3%) and 16 age- and sex-matched healthy volunteers (Control), sympathetic nervous system activity was measured at rest (baseline) and during sympathoneural stimulation (lower body negative pressure (LBNP)) by means of interstitial and plasma noradrenaline (NA) sampling and power spectral analysis. Muscle sympathetic nerve activity (MSNA) was measured before (baseline) and during a cold pressure test. Forearm blood flow was measured during forearm vascular ,- and ,-adrenergic receptor blockade. Results, At baseline, forearm vascular resistance (FVR), plasma NA concentrations, MSNA and heart rate variability were similar in both groups. LBNP-induced vasoconstriction was significantly attenuated in the DM group compared with the Control group (,FVR: 12 ± 4 vs. 19 ± 3 arbitrary units, P < 0·05). The responses of plasma NA and heart rate variability did not differ. Conclusions,, Baseline FVR and sympathetic nerve activity are normal in patients with uncomplicated type 1 diabetes. However, the forearm vasoconstrictor response to sympathetic stimulation is attenuated, which cannot be attributed to an impaired sympathetic responsiveness. [source] Obesity,hypertension: an ongoing pandemicINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 2 2007E. A. Francischetti Summary Considerable evidence has suggested that excessive weight gain is the most common cause of arterial hypertension. This association has been observed in several populations, in different regions of the world. Obesity,hypertension, a term that underscores the link between these two deleterious conditions, is an important public health challenge, because of its high frequency and concomitant risk of cardiovascular and kidney diseases. The obesity,hypertension pandemic imposes a considerable economic burden on societies, directly reflecting on healthcare system costs. Increased renal sodium reabsorption and blood volume expansion are central features in the development of obesity,hypertension. Overweight is also associated with increased sympathetic activity. Leptin, a protein expressed in and secreted by adipocytes, is the main factor linking obesity, increased sympathetic nervous system activity and hypertension. The renin,angiotensin,aldosterone system has also been causally implicated in obesity,hypertension, because angiotensinogen is expressed in and secreted by adipose tissue. Hypoadiponectinemia, high circulating levels of free fatty acids and increased vascular production of endothelin-1 (ET-1) have been reported as potential mechanisms for obesity,hypertension. Lifestyle changes are effective in obesity,hypertension control, though pharmacological treatment is frequently necessary. Despite the consistency of the mechanistic approach in explaining the causal relation between hypertension and obesity, there is yet no evidence that one class of drug is superior to the others in controlling obesity,hypertension. In this review, we present the current knowledge and research in obesity,hypertension, exploring the epidemiologic evidence of the association, its probable pathophysiological mechanisms and treatment issues. [source] Mechanisms underlying the inhibition of the cytochrome P450 system by copper ionsJOURNAL OF APPLIED TOXICOLOGY, Issue 8 2009M. E. Letelier Abstract Copper toxicity has been associated to the capacity of free copper ions to catalyze the production of superoxide anion and hydroxyl radical, reactive species that modify the structure and/or function of biomolecules. In addition, nonspecific Cu2+ -binding to thiol enzymes, which modifies their catalytic activities, has been reported. Cytochrome P450 (CYP450) monooxygenase is a thiol protein that binds substrates in the first and limiting step of CYP450 system catalytic cycle, necessary for the metabolism of lipophilic xenobiotics. Therefore, copper ions have the potential to oxidize and bind to cysteinyl residues of this monooxygenase, altering the CYP450 system activity. To test this postulate, we studied the effect of Cu2+ alone and Cu2+/ascorbate in rat liver microsomes, to independently evaluate its nonspecific binding and its pro-oxidant effects, respectively. We assessed these effects on the absorbance spectrum of the monooxygenase, as a measure of structural damage, and p -nitroanisole O -demethylating activity of CYP450 system, as a marker of functional impairment. Data obtained indicate that Cu2+ could both oxidize and bind to some amino acid residues of the CYP450 monooxygenase but not to its heme group. The differences observed between the effects of Cu2+ and Cu2+/ascorbate show that both mechanisms are involved in the catalytic activity inhibition of CYP450 system by copper ions. The significance of these findings on the pharmacokinetics and pharmacodynamics of drugs is discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Nongenomic Actions of Adrenal Steroids in the Central Nervous SystemJOURNAL OF NEUROENDOCRINOLOGY, Issue 8 2010N. K. Evanson Mineralocorticoids and glucocorticoids are steroid hormones that are released by the adrenal cortex in response to stress and hydromineral imbalance. Historically, adrenocorticosteroid actions are attributed to effects on gene transcription. More recently, however, it has become clear that genome-independent pathways represent an important facet of adrenal steroid actions. These hormones exert nongenomic effects throughout the body, although a significant portion of their actions are specific to the central nervous system. These actions are mediated by a variety of signalling pathways, and lead to physiologically meaningful events in vitro and in vivo. We review the nongenomic effects of adrenal steroids in the central nervous system at the levels of behaviour, neural system activity, individual neurone activity and subcellular signalling activity. A clearer understanding of adrenal steroid activity in the central nervous system will lead to a better ability to treat human disease as well as reduce the side-effects of the steroid treatments already in use. [source] Preclinical Evaluation of Riluzole: Assessments of Ethanol Self-Administration and Ethanol Withdrawal SymptomsALCOHOLISM, Issue 8 2009Joyce Besheer Background:, Many of the neurobehavioral effects of ethanol are mediated by inhibition of excitatory N -methyl- d -aspartate (NMDA) and enhancement of inhibitory ,-amino-butyric-acid (GABA) receptor systems. There is growing interest in drugs that alter these systems as potential medications for problems associated with alcoholism. The drug riluzole, approved for treatment of amyotrophic lateral sclerosis (ALS), inhibits NMDA and enhances GABAA receptor system activity. This study was designed to determine the preclinical efficacy of riluzole to modulate ethanol self-administration and withdrawal. Methods:, Male C57BL/6J mice were trained to lever press on a concurrent fixed-ratio 1 schedule of ethanol (10% v/v) versus water reinforcement during daily 16-hour sessions. Riluzole (1 to 40 mg/kg, IP) was evaluated on ethanol self-administration after acute and chronic (2 week) treatment. To determine if riluzole influences ethanol withdrawal-associated seizures, mice were fed an ethanol-containing or control liquid diet for 18 days. The effects of a single injection of riluzole (30 mg/kg) were examined on handling-induced convulsions after ethanol withdrawal. Results:, Acute riluzole (30 and 40 mg/kg) reduced ethanol self-administration during the first 4 hours of the session, which corresponds to the known pharmacokinetics of this drug. Ethanol self-administration was also reduced by riluzole after chronic treatment. Riluzole (30 mg/kg) significantly decreased the severity of ethanol-induced convulsions 2 hours after ethanol withdrawal. Conclusions:, These results demonstrate that riluzole decreases ethanol self-administration and may reduce ethanol withdrawal severity in mice. Thus, riluzole may have utility in the treatment of problems associated with alcoholism. [source] Heart Rate Variability and Sympathetic Skin Response in Male Patients Suffering From Acute Alcohol Withdrawal SyndromeALCOHOLISM, Issue 9 2006Karl-Jürgen Bär Background: Many symptoms of alcohol withdrawal (AW) such as tachycardia or elevated blood pressure might be explained by increased peripheral and central adrenergic activity. In contrast to many neurochemical studies of sympathetic activation during AW, only very few studies investigated autonomic balance using neurophysiological methods. Methods: We investigated heart rate variability (HRV) and sympathetic skin response (SSR) in male patients suffering from mild AW syndrome (n=20, no treatment required) and in patients with moderate to severe AW syndrome (n=20, clomethiazole treatment) in the acute stage. Sympathovagal influence was quantified using measures of time and frequency domain of HRV as well as modern nonlinear parameters (compression entropy). Furthermore, we obtained latencies and amplitudes of SSR to quantify isolated sympathetic influence. Measures were obtained during the climax of withdrawal symptomatology before treatment, 1 day after climax, and shortly before discharge from hospital. Alcohol withdrawal scores were obtained and correlated to autonomic measures. Results: Ambulatory blood pressure and AW scores revealed characteristic withdrawal symptoms in both patient groups. Apart from the nonlinear parameter compression entropy, Hc, measures of HRV revealed no sign of autonomic dysfunction in contrast to the significantly increased heart rates at the time of admission. Latencies and amplitudes of SSR did not indicate any increase of sympathetic activity. A negative correlation was found between Hc and mental withdrawal symptoms. Conclusions: We show here that classical measures for autonomic nervous system activity such as HRV and SSR are not suitable for describing the autonomic changes seen in acute AW, although a major role for the sympathetic nervous system has been proposed. This might be due to multiple dysregulation of metabolites in AWS or to subtle alcohol-induced damage to neuronal structures, issues that should be addressed in future studies. [source] Restless legs syndrome: Evidence for nocturnal hypothalamic-pituitary-adrenal system activation,MOVEMENT DISORDERS, Issue 8 2010Claudia Schilling MD Abstract Epidemiological studies consistently point to a relationship between restless legs syndrome (RLS) and cardiovascular disease. The mechanism underlying this association is unclear. Activation of the hypothalamic-pituitary-adrenal (HPA) system has been shown to contribute to the metabolic syndrome and an enhanced cardiovascular risk. We investigated cortisol levels as an indicator of HPA system activity in RLS during the nighttime, when RLS symptoms are at their maximum. We assessed nocturnal urinary cortisol excretion in 73 patients with RLS and 34 healthy controls, controlling for age and gender. Urine sampling was paralleled by polysomnographic recordings. We found significantly enhanced nocturnal cortisol excretion in RLS, demonstrating nocturnal HPA system overactivity in RLS. HPA system overactivity is a possible mechanism contributing to the enhanced load of cardiovascular disease in RLS patients. Nocturnal cortisol release showed weak correlations with some polysomnographic parameters of disturbed sleep, making a potential contribution of RLS-induced sleep disruption to HPA system activation conceivable. © 2010 Movement Disorder Society [source] Neuromodulatory Processes of the Brain,Gut AxisNEUROMODULATION, Issue 4 2008Alexandru Gaman MD ABSTRACT Brain,gut axis represents a complex reflex circuit that integrates the communication between cortex and the digestive system. Disturbances of the neuromodulatory processes in the brain,gut axis generate functional digestive disorders mainly centered on the pain symptoms and motility disorders. This article reviews structural and pathophysiologic aspects of the brain,gut axis and explains how the neuromodulatory interventions currently used in order to treat gastrointestinal conditions related to the brain,gut axis disturbances. The neuromodulation can be realized by pharmacologic targeting mainly receptors in the periphery or using electrical stimulation applied at different levels of the nervous system or directly in the muscular layers of the bowels resulting in modulation of the digestive system activity. The efficacy of the methods using electrostimulation is dependent on the parameters of the physical system used: amplitude, frequency, burst time of the electrical current, and also the positioning of the electrodes. While pharmacologic interventions are largely used at the moment, neuromodulatory interventions involving electrical stimulation showed clinical efficacy in research trials and have promise. [source] Continuous Vagus Nerve Stimulation Effects on the Gut-Brain Axis in SwineNEUROMODULATION, Issue 1 2007Idoia Díaz-Güemes DVM ABSTRACT Objectives., This study was designed to assess vagus nerve stimulation effects on the food intake pattern in swine and determine the electrical stimulus direction. Material and Methods., Fifteen Large White pigs were randomly divided into three groups, groups A,C. All animals underwent implantation of a vagus nerve stimulator at the gastro-esophogeal junction. In group A, the stimulation was switched off, whereas stimulation was switched on in groups B and C. Food intake and body weight were registered in groups A and B, but not in group C, which was used to measure direction of stimulation in the vagus and effect on heart rate and blood pressure. Variables measured in group C included the bispectral index, blood pressure, and heart rate. A Student's t -test and one-way analysis of variance were used to detect differences between groups. All animals were sacrificed to identify effects of implantation and stimulation on the vagus nerve. Results., With respect to food intake, there was no difference between groups A and B; however, body weight did register a continuous increase. During stimulation, in group C arterial pressures decreased significantly, whereas the heart rate and bispectral index increased. Conclusion., The stimulation protocol applied in this study was insufficient to cause changes in the feeding behavior of swine; however, it did increase central nervous system activity. [source] The peripheral sympathetic nervous system in human obesityOBESITY REVIEWS, Issue 1 2001M. A. van Baak Summary The peripheral sympathetic nervous system is a key factor in the regulation of energy balance in humans. Differences in sympathetic nervous system activity may contribute to variations in 24 h energy expenditure between individuals. ,-Adrenoceptors play a more important role than ,-adrenoceptors in this regulation. The involvement of both ,1-and ,2-adrenoceptor subtypes has been demonstrated, the role of the ,3-adrenoceptor subtype is not yet clear. Normal or increased levels of sympathetic nervous system activity and reduced reactivity appear to be present in established obesity. Furthermore, the sensitivity for ,-adrenoceptor stimulation is impaired in obesity. The blunted reactivity and sensitivity may contribute to the maintenance of the obese state. There are data to suggest that they may also play a role in the aetiology of obesity, because the impairments often remain after weight reduction. Furthermore, a negative correlation between baseline sympathetic nervous system activity and weight gain during follow-up has been found in Pima Indians. Recently, genetic evidence about the involvement of adrenoceptors in obesity has become available. Although the results of association and linkage studies on polymorphisms in the ,2-, ,3- and ,2-adrenoceptor genes are inconsistent, the functional correlates of some of these polymorphisms (changes in agonist-promoted down-regulation, protein expression levels, lipolytic sensitivity, basal metabolic rate, sympathetic nervous system activity) suggest that they may be important in the aetiology of obesity. [source] Modeling multisystem biological risk in young adults: The Coronary Artery Risk Development in Young Adults StudyAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2010Teresa Seeman Although much prior research has focused on identifying the roles of major regulatory systems in health risks, the concept of allostatic load (AL) focuses on the importance of a more multisystems view of health risks. How best to operationalize allostatic load, however, remains the subject of some debate. We sought to test a hypothesized metafactor model of allostatic load composed of a number of biological system factors, and to investigate model invariance across sex and ethnicity. Biological data from 782 men and women, aged 32,47, from the Oakland, CA and Chicago, IL sites of the Coronary Artery Risk Development in Young Adults Study (CARDIA) were collected as part of the Year 15exam in 2000. These include measures of blood pressure, metabolic parameters (glucose, insulin, lipid profiles, and waist circumference), markers of inflammation (interleukin-6, C-reactive protein, and fibrinogen), heart rate variability, sympathetic nervous system activity (12-hr urinary norepinephrine and epinephrine) and hypothalamic-pituitary-adrenal axis activity (diurnal salivary free cortisol). A "metafactor" model of AL as an aggregate measure of six underlying latent biological subfactors was found to fit the data, with the metafactor structure capturing 84% of variance of all pairwise associations among biological subsystems. There was little evidence of model variance across sex and/or ethnicity. These analyses extend work operationalizing AL as a multisystems index of biological dysregulation, providing initial support for a model of AL as a metaconstruct of inter-relationships among multiple biological regulatory systems, that varies little across sex or ethnicity. Am. J. Hum. Biol. 2010. © 2009 Wiley-Liss, Inc. [source] Thermoregulatory sympathetic nervous system activity and diet-induced waist-circumference reduction in obese Japanese womenAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2009Mami Fujibayashi The present study is designed to investigate how and to what extent sympathovagal behavior in a balanced low-calorie diet relates to favorable changes of body mass, waist circumference, and/or metabolic risk factors. The study involved 28 mildly obese women without clinical complications, who underwent an 8-week calorie restriction program using a 1,200-kcal daily diet with an adequate nutrient content; including two regular meals, and one formula meal replacement. All subjects were examined before and after the dietary intervention. We measured anthropometric parameters, blood pressure, and biochemical blood profiles for lipid metabolism. Autonomic nervous system activity was evaluated by heart rate variability power spectral analysis. The dietary intervention induced moderate, but significant reduction of waist circumference (,5.3% ± 0.8%), body fat percentage (,5.8% ± 0.8%), and body mass (,6.6% ± 0.5%). Linear regression analysis showed that ,very low frequency (VLF) power reflecting energy metabolic- and thermoregulatory sympathetic function significantly correlated to ,waist circumference (r = ,0.53, P < 0.01), ,body fat percentage (r = ,0.39, P < 0.05), ,body mass (r = ,0.43, P < 0.05), ,HDL-cholesterol/total cholesterol ratio (HDL-C/TC) (r = 0.62, P < 0.001), and ,nonesterified fatty acids (NEFA) (r = 0.56, P < 0.01). A stepwise multiple regression analysis additionally revealed that ,waist circumference (P = 0.024), ,HDL-C/TC (P = 0.013), and ,NEFA (P = 0.016) were significant and independent factors, which contributing to the variance in ,VLF power (r2 = 0.61). Although causes and consequences of obesity continue to elude researchers, the present study indicates that thermoregulatory sympathetic activity relates to moderate waist-circumference reduction together with favorable changes of blood lipid profiles after short-term dietary modification in mildly obese women. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc. [source] Methodological considerations in the use of salivary ,-amylase as a stress marker in field researchAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2008Jason A. DeCaro Salivary ,-amylase recently has been identified as a stress-related biomarker for autonomic nervous system activity. This study addresses sample collection and handling considerations for field researchers. Saliva was collected by unstimulated passive drool from 14 adults and pooled. Incubation of pooled saliva at 22 or 37°C for 21 days did not diminish amylase activity. However, sodium azide added at concentrations ,1.12 mg/ml to pooled saliva artificially inflated activity. After dosing cotton rolls within Salivette saliva collection devices with 0.25 to 1.5 ml of unpooled passive drool saliva from six additional adults, recovery of amylase activity was significantly below 100% at all volumes, with increased variance in recovery when the cotton was incompletely saturated (,1.0 ml). Hence, collection by passive drool instead of cotton-containing devices for amylase determinations is recommended, particularly whenever it is impossible to ensure full, uniform cotton saturation, and azide should be avoided as a preservative. Am. J. Hum. Biol., 2008. © 2008 Wiley-Liss, Inc. [source] Adult female crickets, Gryllus texensis, maintain reproductive output after repeated immune challengesPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2007KELLY L. SHOEMAKER Abstract Both immunity and reproduction are thought to be energetically costly and therefore likely to make trade-offs with one another. To assess whether increasing immune system activity results in a decline in egg production, the immune system in the cricket Gryllus texensis is activated over a period of 12 days with regular injections of lipopolysaccharide (LPS) derived from Serratia marcescens, and the number of eggs laid during this time counted. Egg quality is also assessed by measuring total protein of eggs laid, fertilization and hatching success, and the weight of individual eggs laid after the series of injections. Indirect evidence suggests that LPS induces an immune response in G. texensis. However, the number of eggs produced is not affected. There is also no effect of repeated LPS injections on female weight, egg protein content, or fertilization and hatching success. Taken together, these results suggest that with food and water provided ad libitum, females can protect many aspects of fitness in the face of increased immune system activity. However, there is some evidence to suggest that large (100 ,g) doses of LPS lead to reduced female longevity, and also in egg weight that could affect offspring success. Although the possibility exists that the decline in lifespan and egg weight after high-dose injections reflects a trade-off between reproduction and immune investment, another possibility is that these doses yield nonspecific effects, or that the high-dose induces an overwhelming immune response that leads to self-damage. [source] Are there ethnic differences in sleep architecture?AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2002Judi Profant The possibility of ethnic differences in sleep architecture was initially examined in conjunction with studies of sleep apnea (study 1). This possibility was then examined in another cohort of patients to determine whether the results might generalize (study 2). Polysomnography was obtained in both cohorts as part of larger protocols investigating sympathetic nervous system activity, blood pressure, and sleep. Sleep monitoring took place in an inpatient clinical research center of a university hospital. Study 1 focused on sleep apnea physiology and involved volunteers with sleep apnea who were otherwise healthy. Study 2 focused on differences in stress reactivity between American Black and White subjects and involved hypertensive and normotensive volunteers who were otherwise healthy. Analyses include 61 participants from study 1 and 35 participants from study 2. Ethnicity in both cohorts was determined by self-report. Participants in both studies were monitored during sleep with traditional polysomnography including electroencephalography (EEG), electromyography (EMG), electrooculography (EOG), and oximetry. In Study 1, Blacks had longer TST (P < 0.01), more REM sleep (P < 0.05), and less WASO (P < 0.05) than Whites. After controling for RDI, Blacks had longer TST and spent a smaller percentage of time in deep sleep (P < 0.05). In study 2, Blacks had longer TST and REM sleep, lower percent deep sleep, and lower percent deep sleep controling for RDI (P < 0.05). In two separate studies, Blacks had longer TST, more minutes of REM, and lower percentage deep sleep. These findings suggest possible ethnic differences in sleep architecture. Am. J. Hum. Biol. 14:321,326, 2002. © 2002 Wiley-Liss, Inc. [source] Alpha power is influenced by performance errorsPSYCHOPHYSIOLOGY, Issue 2 2009Joshua Carp Abstract Error commission evokes changes in event-related potentials, autonomic nervous system activity, and behavior, presumably reflecting the operation of a cognitive control network. Here we test the hypothesis that errors lead to increased cortical arousal, measurable as changes in electroencephalogram (EEG) alpha band power. Participants performed a Stroop task while EEG was recorded. Following correct responses, alpha power increased and then decreased in a quadratic pattern, implying transient mental disengagement during the intertrial interval. This trend was absent following errors, which elicited significantly less alpha power than correct trials. Moreover, post-error alpha power was a better predictor of individual differences in post-error slowing than the error-related negativity (ERN), whereas the ERN was a better predictor of post-error accuracy than alpha power. These findings imply that changes in cortical arousal play a unique role in modulating post-error behavior. [source] Modulation of the human mirror neuron system during cognitive activityPSYCHOPHYSIOLOGY, Issue 6 2008Suresh D. Muthukumaraswamy Abstract In this experiment we examined the relationship between the mirror neuron system and increased attention caused by task demands. Whole head MEG recordings were made from 13 participants who were asked to passively observe finger movement sequences, observe these sequences with the knowledge they would later have to perform the sequence presented, and finally, to perform a nonmotor mathematics task based on the finger-movement sequences. Beta-band (15,35 Hz) sensorimotor desynchronization was found in overlapping areas during passive observation and in a separate motor execution condition, indicating the activity of the human mirror neuron system. The beta desynchronization in these areas was enhanced relative to passive viewing when participants had to watch the stimuli to later imitate and when they performed the mathematics task, indicating that mirror neuron system activity can be modulated by attention. [source] Ethnic (Black-White) Contrasts in 24-Hour Heart Rate Variability in Male Adolescents with High and Low Blood Pressure: The Bogalusa Heart StudyANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2000Elaine M. Urbina M.D. Background: Heart rate variability (HRV) has been used to study autonomic effects on the heart. The time-domain measure RMSSD (root mean square of successive differences) represents high frequency (HF) changes in HRV reflecting parasympathetic nervous system activity (PS). The frequency-domain ratio of low to high power (LF/HF) represents sympathetic (SYMP) to PS balance. In adults, increased SYMP tone has been found in hypertensive as compared to normals. The present study was performed to look for differences in HRV by race and between young subjects with high and low levels of diastolic blood pressure (DBP). Methods: Subjects included 34 healthy males age 13,17 years (53% white). Half were selected with K4 DBP < 85th% for height (HT) measured twice, 3,5 years apart. Half had DBP < 15th% for HT. Subjects underwent a physical examination including BP, HT, WT, and ECG prior to Holter monitor application. HRV data was analyzed from 24-hour Holter recordings obtained during normal activity. Results: The RMSSD was lower in whites compared to blacks for day, night, and 24-hour average (P , 0.05) with day-time measurements showing the largest racial difference. This suggests increased PS tone in blacks especially with activity. The LF/HF ratio was higher in whites for all times, reaching significance during the day (all P , 0.05) suggesting SYMP predominance in whites during activity. Subjects with higher levels of DBP had lower RMSSD and higher LF/HF ratio for all times, but these did not reach statistical significance. Conclusions: There is a trend towards SYMP predominance in children with higher DBP. Healthy white adolescents exhibit increased SYMP tone compared to blacks when measured during normal daytime activity. [source] Prolonging Cell-Free Protein Synthesis by Selective Reagent AdditionsBIOTECHNOLOGY PROGRESS, Issue 3 2000Dong-Myung Kim Factors causing the early cessation of protein synthesis have been studied in a cell-free system from Escherichia coli. We discovered that phosphoenol pyruvate (PEP), the secondary energy source for ATP regeneration, and several amino acids are rapidly degraded during the cell-free protein synthesis reaction. The degradation of such compounds takes place even in the absence of protein synthesis. This degradation severely reduces the capacity for protein synthesis. The lost potency was completely recovered when the reaction mixture was supplied with additional PEP and amino acids. Of the 20 amino acids, only arginine, cysteine, and tryptophan were required to restore system activity. Through repeated additions of PEP, arginine, cysteine,and tryptophan, the duration of protein synthesis was greatly extended. In this fed-batch reaction, after a 2 h incubation, the level of cell-free synthesized chloramphenicol acetyl transferase (CAT) reached 350 ,g/mL, which is 3.5 times the yield of the batch reaction. Addition of fresh magnesium further extended the protein synthesis. As a result, through coordinated additions of PEP, arginine, cysteine, tryptophan, and magnesium, the final concentration of cell-free synthesized CAT increased more than 4-fold compared to a batch reaction. SDS-PAGE analysis of such a fed-batch reaction produced an obvious band of CAT upon Coomassie Blue staining. [source] 2357: Autonomic nervous system and endothelial peripheral dysfunction in normal tension glaucoma patientsACTA OPHTHALMOLOGICA, Issue 2010J WIERZBOWSKA Purpose To define parameters of autonomic nervous system activity and peripheral vascular reactive hyperemia in normal tension glaucoma patients. Methods Ambulatory 24-hour electrocardiogram and blood pressure (BP) monitoring by using Lifecard CF and SpaceLab 90207-30 combined with occlusion provocation test were carried out in 54 NTG patients (44 women, mean age 59.7) and 43 matched control subjects (34 women, mean age 57.0). Heart rate variability (HRV) time and frequency domain parameters [low-frequency (LF), high-frequency (HR) and LF/HF ratio], and blood pressure variability (BPV) were calculated and analyzed for both study groups. Postocclusive hyperemia response parameters (TM - time to peak flow, TH ,half-time hyperaemia, TR ,time to rest flow, BZ-biological zero and MAX , maximum hyperemic response) were compared for patients with a nocturnal fall in mean BP (MPB) of less than 10% (non-dippers), of 10-20% (dippers) and of more than 20% (over-dippers) Results NTG patients demonstrated higher LF and LF/HF values for 24-hour period, day-time and night time than control subjects. There was no difference in BPV between study groups (10.4 ± 1.9 vs. 10.5 ± 2.1, p=0.790). In NTG patients, TH was significantly higher (79.0 ± 80.9 s vs. 51.5 ± 35.3 s, p=0.028) and BZ was significantly lower (2.3 ± 1.0 vs. 3.1 ± 2.0, p=0.009) as compared to the control group. There was statistically significant difference between NTG non-dippers, dippers and over,dippers in the BZ parameter (2.3 ± 0.9 vs. 2.7 ± 1.3 vs. 1.4 ± 0.4 p=0.024). Conclusion NTG patients exhibit abnormal ANS system activity and a different systemic hyperemia response as compared with healthy subjects. [source] Association of neuropeptides with Th1/Th2 balance and allergic sensitization in childrenCLINICAL & EXPERIMENTAL ALLERGY, Issue 11 2006G. Herberth Summary Background Among neurogenic factors, the neuropeptides have an important regulatory influence on immune system activity and may lead to allergic sensitization. Objective The aim of our study was to investigate the relationship of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM) and substance P (SP) on modulation of Th1/Th2 balance and allergic sensitization in children. Methods Within the LISAplus (Life style,Immune system,Allergy) study, blood samples of 321 six-year-old children were analysed for concentration of neuropeptides, Th1 and Th2 cytokines, transcription factors for T cell regulation and suppressors of cytokine signalling. In addition, samples were screened for specific IgE against inhalant and food allergens. Results Children with high SOM values showed a Th2 polarization and a reduced expression of FOXP3, the marker for regulatory T cells. High (VIP) levels correlated inversely with the expression of T cell transcription factors (Tbet and SOCS3). In contrast, elevated levels of SP were associated with reduced GATA3 and SOCS3 expression and with increased IFN-, concentrations. Allergic sensitization was more prevalent in children with higher SOM and VIP concentrations but not associated with SP levels. Conclusion Our data reveal an association between neuropeptides and modulatory effects on immune cells in vivo, especially on Th1/Th2 balance with a correlation to allergic sensitization in children. We suggest that elevated SOM and VIP concentrations and the inducing factors should be considered as allergy risk factors. [source] Rhodiola rosea: A Versatile AdaptogenCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 3 2005Farhath Khanum ABSTRACT Rhodiola rosea (rose root) belonging to the family Crassulaceae is a popular medicinal plant in Russia, Scandinavia, and many other countries. Extracts of the roots of this plant have been found to favorably affect a number of physiological functions including neurotransmitter levels, central nervous system activity, and cardiovascular function. It is being used to stimulate the nervous system, decrease depression, enhance work performance, eliminate fatigue, and prevent high-altitude sickness. Most of these effects have been ascribed to constituents such as salidroside (rhodioloside), rosavins, and p-tyrosol. It has also been found to be a strong antioxidant and anticarcinogen due to the presence of several phenolic compounds. Adaptogens are plant extracts that allow an organism to counteract adverse physical, chemical, and biological stressors by generating nonspecific resistance. Adaptogens are known to increase the availability of energy during the day, reduce stressed feelings, increase endurance, and increase mental alertness. This multipurpose medicinal plant (R. rosea), with adaptogenic properties that increase the body's nonspecific resistance and normalize functions, has been traditionally grown and used in Russia and Mongolia. Due to increasing consumer demands toward natural health products and the growing interests in the secondary metabolites of plants and their application in biotechnology and therapy, much focus has been put on the rose root and its medical properties. The rose root imparts normalizing influences on adverse physical, chemical, and biological disturbances but is otherwise innocuous. In India, the plant has been growing wild in the high altitudes of the Himalayas. The Defence Research and Development Organization in India has taken on the responsibilities of its conservation, as well as the development of multiple management practices and the development of health foods, supplements, and nutraceuticals in India. [source] | |||||||||||||||||||||||||||||||