Home About us Contact
|
Home About us Contact | ||
|
|
||
Resting Conditions (resting + condition)
Selected AbstractsRELAXANT EFFECT OF ADRENOMEDULLIN ON BOVINE ISOLATED IRIS SPHINCTER MUSCLE UNDER RESTING CONDITIONSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2005Y Uchikawa SUMMARY 1.,The mechanisms involved in the fine adjustment of iris sphincter muscle tone are largely unknown. The aim of the present study was to clarify the effects of adrenomedullin on the resting tension of the bovine isolated iris sphincter muscle. 2.,The motor activity of the bovine isolated iris sphincter muscle was measured isometrically. The effects of adrenomedullin on resting tension were analysed in the presence of indomethacin. The presence of adrenomedullin mRNA in the preparation was determined by reverse transcription,polymerase chain reaction. Immunolabelling for adrenomedullin was also performed. 3.,Adrenomedullin significantly decreased the resting tension of the muscle. The relaxant effect of adrenomedullin was significantly inhibited by adrenomedullin (22,52), a putative antagonist for the adrenomedullin receptor, or calcitonin gene-related peptide (CGRP) (8,37), a putative antagonist for the CGRP1 receptor. The relaxant effect was almost completely blocked by a combination of adrenomedullin (22,52) and CGRP (8,37). 4.,The relaxant effect of adrenomedullin was also significantly diminished by 2,,5,-dideoxyadenosine, an inhibitor of adenylate cyclase, NG -nitro- l -arginine, an inhibitor of nitric oxide synthesis, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase. 5.,Reverse transcription,polymerase chain reaction analysis showed that adrenomedullin mRNA was expressed in the muscle strip. Immunopositive staining for adrenomedullin was detected in blood vessel cells and in the iris sphincter muscle cells. 6.,These results suggest that adrenomedullin may be an autocrine and paracrine regulator of the resting tension of the iris sphincter muscle. Its biological effects may be due to the direct involvement of adrenomedullin receptors and also to the stimulation of CGRP1 receptors. The stimulation of these receptors by the peptide leads to the activation of adenylate cyclase and soluble guanylate cyclase and subsequent relaxation of the muscle strip. [source] Micro- and macroscopic characteristics to stage gonadal maturation of female Baltic codJOURNAL OF FISH BIOLOGY, Issue 2 2003J. Tomkiewicz A set of histological characteristics to judge ovarian development was established and used to elaborate morphological criteria of 10 maturity stages of Baltic cod Gadus morhua sampled throughout the annual cycle to represent different macroscopic maturity stages. The applied characteristics confirmed most stages of the macroscopic scale, but the separation of late immature and resting mature females remained imprecise. Atretic vitellogenic oocytes or encapsulated residual eggs identified the resting condition morphologically, but not all ovaries with visible signs of previous spawning showed such features. One ovarian stage that was previously classified as ,ripening' was changed to ,spawning', owing to the prevalence of hydrated eggs and empty follicles. Ovaries with malfunctions were defined by a separate stage. Macroscopic criteria were revised by comparing the gross anatomy of ovaries with their histology. Female length and gonado-somatic index supported stage definitions, but substantial variation in Fulton's condition factor and the hepato-somatic index rendered these of little use for this purpose. The time of sampling influenced staging accuracy. A female spawner probability function based on the proportion of ripening and ripe specimens in early spring seems to be the most appropriate method to estimate spawner biomass and reproductive potential. [source] The Effect of Acute Psychological Stress on QT Dispersion in Patients with Coronary Artery DiseasePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2009MUSTAFA HASSAN M.D. Background: An acute psychological stress can precipitate ventricular arrhythmias and sudden cardiac death in patients with coronary artery disease (CAD). However, the physiologic mechanisms by which these effects occur are not entirely clear. Mental stress-induced myocardial ischemia occurs in a significant percentage of the CAD population. It is unknown if the proarrhythmic effects of psychological stress are mediated through the development of myocardial ischemia. Objectives: To examine the effects of psychological stress on QT dispersion (QTd) among CAD patients and whether these effects are mediated via the development of myocardial ischemia. Methods: Psychological stress was induced using a public speaking task. Twelve-lead electrocardiograms (ECG) were recorded at rest, during mental stress, and during recovery. QTd was calculated as the difference between the longest and the shortest QT interval in the 12-lead ECG. Rest-stress myocardial perfusion imaging was also performed to detect mental stress-induced myocardial ischemia. Results: Mental stress induced a significant increase in QTd compared to the resting condition (P < 0.001). This effect persisted beyond the first 10 minutes of recovery (P < 0.001). QTd was significantly associated with the development of mental stress ischemia with ischemic patients having significantly higher QTd during mental stress than nonischemic patients (P = 0.006). This finding remained significant after controlling for possible confounding factors (P = 0.01). Conclusion: An acute psychological stress induces a significant increase in QTd, which persists for more than 10 minutes after the cessation of the stressor. This effect seems to be, at least partially, mediated by the development of mental stress-induced myocardial ischemia. [source] Potential association between endogenous leptin and sympatho-vagal activities in young obese Japanese womenAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2003Tamaki Matsumoto Leptin is an adipocyte-derived hormone that decreases food intake and increases energy expenditure through the activation of the sympathetic nervous system (SNS). Notwithstanding recent intensive research, the underlying physiological mechanism of leptin as well as the etiology of obesity in humans remains elusive. The present study attempted to investigate the potential association between endogenous circulating leptin and sympatho-vagal activities in age- and height-matched obese and nonobese healthy young women. Plasma leptin concentrations were measured by radioimmunoassay. The autonomic nervous system activity was assessed during the resting condition by means of a recently devised power spectral analysis of heart rate variability, which serves to identify three separate frequency components, very low (VLO), low (LO), and high (HI). Plasma leptin concentrations were greater in the obese than in the control group (45.7 ± 5.89 vs. 11.2 ± 1.10 ng · ml,1, P < 0.01). As to the contribution of endogenous leptin to SNS activity, both the ratios of the VLO frequency component reflecting thermoregulatory sympathetic function and the global SNS index [(VLO + LO)/HI] to plasma leptin concentration were markedly reduced in the obese compared to the control group (VLO per leptin: 5.9 ± 1.39 vs. 37.8 ± 8.1 ms2 · ml · ng,1, P < 0.01; SNS index per leptin: 0.04 ± 0.008 vs. 0.33 ± 0.01 ml,,·,ng,1, P < 0.01). Additionally, a nonlinear regression analysis revealed that these ratios exponentially decreased as a function of body fat content (VLO per leptin r2 = 0.57, P < 0.01; SNS index per leptin r2 = 0.53, P < 0.01). Our data suggest that reduced sympathetic responsiveness to endogenous leptin production, implying peripheral leptin resistance, might be a pathophysiological feature of obesity in otherwise healthy young women. The findings regarding the association of leptin, body fat content, and SNS activity further indicate that the 30% of total body fat, which has been used as a criterion of obesity, might be a critical point at which leptin resistance is induced. Am. J. Hum. Biol. 15:8,15, 2003. © 2002 Wiley-Liss, Inc. [source] Long-Term Efficacy of Subcutaneous Sweat Gland Suction Curettage for Axillary Hyperhidrosis: A Prospective Gravimetrically Controlled StudyDERMATOLOGIC SURGERY, Issue 9 2008STEPHANIE DARABANEANU PHD BACKGROUND Subcutaneous sweat gland suction curettage (SSGSC) is gaining acceptance as a therapy for axillary hyperhidrosis. Despite its acceptance, there remains a lack of prospective data describing the efficacy and long-term outcome of SSGSC. OBJECTIVE We examined the sweat rates and patients' satisfaction of 12 months following SGSC in 28 patients with axillary hyperhidrosis. METHODS Axillary sweat rates were determined by semiquantitative gravimetry. A questionnaire was used to determine patients' satisfaction. RESULTS A 58% reduction in sweat rate under resting conditions and an 85% reduction during aerobic exercise in sweat rates was observed. A subdivision of patients into three groups based on their baseline preoperative sweat rates (<25, 25,50, and >50 mg/min) showed that patients with resting sweat rates over 25 mg/min benefited particularly from this procedure, whereas patients with less than 25 mg/min did not. CONCLUSION SSGSC produces a significant reduction in the preoperative sweat rates. A low complication rate and a high degree of patient satisfaction were observed. Long-term follow-up evaluations demonstrate a low number of relapses, making SSGSC a convenient and satisfactory method of treating axillary hyperhidrosis. It should be considered in patients refractory to conventional therapies with baseline sweat rates greater than 25 mg/min. [source] Low-fat oxidation may be a factor in obesity among men with schizophreniaACTA PSYCHIATRICA SCANDINAVICA, Issue 6 2009J.-K. Sharpe Objective:, Obesity associated with atypical antipsychotic medications is an important clinical issue for people with schizophrenia. The purpose of this project was to determine whether there were any differences in resting energy expenditure (REE) and respiratory quotient (RQ) between men with schizophrenia and controls. Method:, Thirty-one men with schizophrenia were individually matched for age and relative body weight with healthy, sedentary controls. Deuterium dilution was used to determine total body water and subsequently fat-free mass (FFM). Indirect calorimetry using a Deltatrac metabolic cart was used to determine REE and RQ. Results:, When corrected for FFM, there was no significant difference in REE between the groups. However, fasting RQ was significantly higher in the men with schizophrenia than the controls. Conclusion:, Men with schizophrenia oxidised proportionally less fat and more carbohydrate under resting conditions than healthy controls. These differences in substrate utilisation at rest may be an important consideration in obesity in this clinical group. [source] Redistribution of small GTP-binding protein, Rab27B, in rat parotid acinar cells after stimulation with isoproterenolEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2009Akane Imai Small GTP-binding protein, Rab27, has been implicated in the regulation of different types of membrane trafficking, including melanosome transport in melanocytes and regulated secretion events in a wide variety of secretory cells. We have previously shown that Rab27 is involved in the control of isoproterenol (IPR)-induced amylase release from rat parotid acinar cells. Although Rab27 is predominantly localized on secretory granules under resting conditions, changes to its intracellular localization after ,-stimulation have never been elucidated. The present study investigated IPR-induced redistribution of Rab27B in the parotid acinar cells, revealing translocation from secretory granules to the subapical region after 5 min of IPR treatment and then diffusion into the cytosol after 30 min of IPR treatment. Dissociation of Rab27B from the apical plasma membrane is probably mediated through the Rab GDP dissociation inhibitor (GDI) in the cytosol extracting GDP-bound Rab protein from membranes, as a dramatic increase in the amount of the Rab27B,GDI complex in the cytosol was observed 30 min after stimulation with IPR. These results indicate that, in parotid acinar cells, Rab27B is translocated, in a time-dependent manner, from secretory granules into the apical plasma membrane as a result of exposure to IPR, and then into the cytosol through binding with the GDI. [source] The NMDA receptor antagonist memantine as a symptomatological and neuroprotective treatment for Alzheimer's disease: preclinical evidenceINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue S1 2003Wojciech Danysz Abstract There is increasing evidence for the involvement of glutamate-mediated neurotoxicity in the pathogenesis of Alzheimer's disease (AD). We suggest that glutamate receptors of the N-methyl-D-aspartate (NMDA) type are overactivated in a tonic rather than a phasic manner in this disorder. This continuous mild activation may lead to neuronal damage and impairment of synaptic plasticity (learning). It is likely that under such conditions Mg2+ ions, which block NMDA receptors under normal resting conditions, can no longer do so. We found that overactivation of NMDA receptors using a direct agonist or a decrease in Mg2+ concentration produced deficits in synaptic plasticity (in vivo: passive avoidance test and/or in vitro: LTP in the CA1 region). In both cases, memantine,an uncompetitive NMDA receptor antagonists with features of an ,improved' Mg2+ (voltage-dependency, kinetics, affinity),attenuated this deficit. Synaptic plasticity was restored by therapeutically-relevant concentrations of memantine (1,,M). Moreover, doses leading to similar brain/serum levels provided neuroprotection in animal models relevant for neurodegeneration in AD such as neurotoxicity produced by inflammation in the NBM or ,-amyloid injection to the hippocampus. As such, if overactivation of NMDA receptors is present in AD, memantine would be expected to improve both symptoms (cognition) and to slow down disease progression because it takes over the physiological function of magnesium. Copyright © 2003 John Wiley & Sons, Ltd. [source] Prediction of general mental ability based on neural oscillation measures of sleepJOURNAL OF SLEEP RESEARCH, Issue 3 2005RÓBERT BÓDIZS Summary The usual assessment of general mental ability (or intelligence) is based on performance attained in reasoning and problem-solving tasks. Differences in general mental ability have been associated with event-related neural activity patterns of the wakeful working brain or physical, chemical and electrical brain features measured during wakeful resting conditions. Recent evidences suggest that specific sleep electroencephalogram oscillations are related to wakeful cognitive performances. Our aim is to reveal the relationship between non-rapid eye movement sleep-specific oscillations (the slow oscillation, delta activity, slow and fast sleep spindle density, the grouping of slow and fast sleep spindles) and general mental ability assessed by the Raven Progressive Matrices Test (RPMT). The grouping of fast sleep spindles by the cortical slow oscillation in the left frontopolar derivation (Fp1) as well as the density of fast sleep spindles over the right frontal area (Fp2, F4), correlated positively with general mental ability. Data from those selected electrodes that showed the high correlations with general mental ability explained almost 70% of interindividual variance in RPMT scores. Results suggest that individual differences in general mental ability are reflected in fast sleep spindle-related oscillatory activity measured over the frontal cortex. [source] Pharmacokinetics and pharmacodynamic effects of ABT-627, an oral ETA selective endothelin antagonist, in humansBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 6 2000Marianne C. Verhaar Aims, Endothelins (ETs) may play a role in the pathogenesis of a variety of cardiovascular diseases. The present study was designed to investigate the pharmacokinetic and pharmacodynamic effects of the orally active ETA selective receptor antagonist ABT-627 in healthy humans. Methods, Healthy volunteers were included in two studies with cross-over design. Subjects received single or multiple dose (an 8 day period) administration of oralABT-627 or matched placebo, in a dose range of 0.2,40 mg. The pharmacokinetics of ABT-627 were described and its effects on systemic haemodynamics under resting conditions and on forearm vasoconstriction in response to ET-1 were assessed. Results, ABT-627 was generally well tolerated in both studies, with transient headache being the most reported adverse event (in 62%vs 4% during placebo, P < 0.05, for Study 1 and in 42%vs 60%, P = 0.2, for Study 2). ABT-627 was rapidly absorbed, reaching maximum plasma levels at ,,1 h post dose. Single dose ABT-627, at a dose of 20 and 40 mg, inhibited ET-1 induced forearm vasoconstriction at 8 h post dose. Eight days ABT-627 treatment, at a dose level of 5 mg and above, also effectively blocked forearm vasoconstriction to ET-1. ABT-627 caused a significant reduction in peripheral resistance as compared with placebo (16 ± 1 vs 19 ± 1, 18 ± 2 vs 23 ± 3, 15 ± 1 vs 17 ± 1 AU at 1, 5, 20 mg in Study 2) with only a mild decrease in blood pressure (79 ± 2 vs 84 ± 3, 80 ± 4 vs 90 ± 5, 75 ± 3 vs 79 ± 1 at 1, 5, 20 mg in Study 2). ABT-627 caused a moderate dose-dependent increase in circulating immunoreactive ET levels (a maximal increase of 50% over baseline at the 20 mg dose level). Conclusions, The oral ETA receptor blocker ABT-627 is well tolerated, rapidly absorbed, effectively blocks ET-1 induced vasoconstriction and causes a decrease in total peripheral resistance and mean arterial pressure. Our data suggest that ABT-627 may be a valuable tool in treatment of cardiovascular disease. [source] Development and evaluation of a simple calorimeter for the measurement of resting metabolismCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue S4 2002Toshiyo Tamura Summary 1.,A simple calorimeter based on the measurement of oxygen uptake has been developed. 2.,A respiratory simulator was used to evaluate oxygen uptake at different flow rates. A known concentration of mixed gases flows into the calorimeter via the respiratory simulator. Oxygen concentration and flow rate were measured and stored to memory for further analysis. 3.,Results indicate that large errors occur at low flow rates, but that the error is less than 5% under normal conditions. 4.,This device can be used to measure oxygen uptake under resting conditions. [source] | ||||||||||||||||||||||