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Acute Effects (acute + effects)
Selected AbstractsTemporary Epicardial Ventricular Stimulation in Patients with Atrial Fibrillation: Acute Effects of Ventricular Pacing Site on Bypass Graft FlowsJOURNAL OF CARDIAC SURGERY, Issue 4 2009Navid Madershahian M.D. This study aimed to evaluate the optimal epicardial ventricular pacing site in patients with AF following coronary artery bypass surgery (CABG). Methods: In 23 consecutive patients (mean age = 69.2 ± 1.9 years, gender = 62% male, ejection fraction [EF]= 50.4 ± 2.1%) monoventricular stimulations (VVI) were tested with a constant pacing rate of 100 bpm. The impact of ventricular pacing on bypass graft flow (transit-time flow probe) and pulsatility index (PI) were measured after lead placement on the mid paraseptal region of the right (RVPS) and the left (LVPS) ventricle, on the right inferior wall (RVIW), and on the right ventricular outflow tract (RVOT). In addition, hemodynamic parameters were measured. Patients served as their own control. Results: Comparison of all tested pacing locations revealed that RVOT stimulation provided the highest bypass grafts flows (59.9 ± 6.1 mL/min) and PI (2.2 ± 0.1) when compared with RVPS (51.3 ± 4.7 mL/min, PI = 2.6 ± 0.2), RVIW (54.0 ± 5.1 mL/m; PI = 2.4 ± 0.2), and LVPS (53.1 ± 4.5 mL/min; PI = 2.3 ± 0.1), respectively (p < 0.05). When analyzing patients according to their preoperative LV function (group I = EF > 50%; group II = EF < 50%), higher bypass graft flows were observed with RVOT pacing in patients with lower EF (p = n.s.). Conclusions: Temporary RVOT pacing facilitates optimal bypass graft flows when compared with other ventricular pacing sites and should be the preferred method of temporary pacing in cardiac surgery patients with AF. Especially in patients with low EF following CABG, RVOT pacing may improve myocardial oxygen conditions for the ischemic myocardium and enhance graft patency in the early postoperative period. [source] Acute Effects of Low Doses of Red Wine on Cardiac Conduction and Repolarization in Young Healthy SubjectsALCOHOLISM, Issue 12 2009Matteo Cameli Background:, Moderate to high blood concentrations of ethanol have been shown to yield acute changes in cardiac electrophysiological properties, but the effect of low concentrations have never been assessed. The role of concomitant changes in clinical variables or cardiac dimensions is also still unknown. This study aimed at exploring the acute effects of low doses of ethanol, administered as Italian red wine, on conduction, depolarization, and repolarization electrocardiographic (ECG) intervals in a population of healthy subjects. Methods:, Forty healthy young volunteers drank a low quantity of red wine (5 ml/kg), and an equal volume of fruit juice in separate experiments. Heart rate, P-wave duration, PR interval, QRS duration, QT interval, corrected QT interval, QT dispersion, and corrected QT dispersion were assessed at baseline and after 60 minutes from challenge. Results:, Mean blood ethanol concentration after drinking was 0.48 ± 0.06 g/l. Compared to the control challenge, significant changes after red wine intake were observed in P-wave duration (from 101 ± 11 to 108 ± 14 milliseconds, p = 0.0006), PR interval (from 153 ± 15 to 167 ± 17 milliseconds, p < 0.0001), QT interval (from 346 ± 28 to 361 ± 24 milliseconds, p < 0.0001), and corrected QT interval (from 388 ± 24 to 402 ± 30 milliseconds, p = 0.0006). None of these changes showed correlations with modifications in clinical or echocardiographic variables. In multivariate analyses aimed at exploring predictors of ECG changes, none of the variables entered the final models. Conclusions:, Low doses of red wine acutely slow cardiac conduction and prolong repolarization in normal individuals. These changes are poorly predictable. The potential arrhythmogenic impact of these effects is worthy of exploration. [source] Acute Effects of Ethanol on Behavior of Adolescent Rats: Role of Social ContextALCOHOLISM, Issue 3 2001Elena I. Varlinskaya Background: First experiences with alcohol in humans occur predominantly in adolescence, and to a large extent the attractiveness of alcohol at this age is based on its ability to facilitate certain forms of social behavior (social facilitation). Adolescence is strongly marked by a focus on peer relationships, and the social nature of the situation plays an important role in responsiveness to alcohol. Peer-directed social activity of adolescent rats may be a valuable experimental model for the study of ethanol-induced changes in social behavior and assessment of the role of the social context in responsiveness to ethanol. Method: In the present study we used a modified dyad social interaction test to characterize acute effects of ethanol on different forms of social behavior (social investigation, contact behavior, and play) and social motivation (preference/avoidance of a peer) in adolescent rats. Ethanol effects on behavior directed toward a peer were compared with those induced by exposure to an inanimate novel object. Results: In the social context, the effects of ethanol were dose-dependent and biphasic. Low doses of ethanol (0.25,0.75 g/kg) produced apparent social facilitation (increased social activity and enhanced social preference), whereas higher doses (3 and 4 g/kg) caused social inhibition (decreased social activity and avoidance of a peer). This pattern was not observed for a nonsocial stimulus: Although overall activity in the nonsocial context was suppressed by 2 and 3 g/kg of ethanol, 0.5 g/kg of ethanol did not activate overall activity directed to the inanimate object. Conclusions: These findings demonstrate that the social nature of the testing situation plays an important role in responsiveness to alcohol in adolescence, especially to its activating effects. The results suggest also that the study of ethanol effects on social behavior of adolescent rats may be an effective tool for the study of adolescent alcohol use and abuse. [source] Acute Effects of Ethanol on Kainate Receptors in Cultured Hippocampal NeuronsALCOHOLISM, Issue 2 2000Edmar T. Costa Background: Kainate receptors are a subclass of ionotropic glutamate receptors that regulate excitability and mediate synaptic transmission and plasticity in the hippocampus. The acute effects of ethanol on these receptors are not completely understood. Methods: The acute effects of ethanol on pharmacologically isolated kainate receptor-mediated currents were studied in cultured hippocampal neurons obtained from neonatal rats. Whole-cell patch-clamp electrophysiological techniques were used for these studies. LY303070 (GYKI-53784), a potent AMPA (,-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor-selective noncompetitive antagonist, was used to isolate kainate currents. Results: Kainate receptor-mediated currents corresponded to 7% of the total non- N -methyl- d -aspartate (non-NMDA) currents in these neurons and were reduced to 24% of control values in the presence of 15 ,M lanthanum. These kainate receptor-mediated currents were significantly inhibited by ethanol concentrations of 50 mM or more. Under our recording conditions, ethanol inhibited non-NMDA receptor- and NMDA receptor-mediated currents to a similar extent as kainate receptor-mediated currents. Western blot analysis indicated that glutamate receptor-5 and -6/7 subunits, and kainic acid-2 subunits are expressed in these cultured hippocampal neurons. Conclusions: The present results suggest that kainate receptors are important targets for the actions of ethanol in the central nervous system. [source] Acute Effects of Moxonidine on Cardiac Autonomic ModulationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2010DAYIMI KAYA M.D. Background: Moxonidine, an imidazoline I1 receptor agonist, is a centrally acting antihypertensive agent having sympatholytic effect. However, there are only limited data regarding the effects of this drug on autonomic cardiac functions. Methods and results: In this study we investigated the acute effects of moxonidine on cardiac autonomic modulation by heart rate variability (HRV) analysis. The effects of oral 0.4-mg moxonidine were studied on 11 healthy male volunteers in a randomized, double-blind, placebo controlled, and crossover study. After 15 minutes rest, time and frequency domain parameters of HRV were calculated from 5-minute continue electrocardiography recordings in supine position, during controlled respiration (15 breath/min) and during handgrip exercise before and 1 hour after taking placebo or moxonidine. Baseline parameters before taking placebo and moxonidine were similar (P > 0.05). Moxonidine, but not placebo, caused an increase in heart failure (HF) (119 ± 21 vs 156 ± 23, P = 0.029) and HFnu (39 ± 4 vs 47 ± 4, P = 0.033) and decrease in LFnu (61 ± 4 vs 53 ± 4, P = 0.033) and LF/HF ratio (1.96 ± 0.36 vs 1.12 ± 0.35, P = 0.010) in supine position compared with baseline parameters. However, there was no difference in other time or frequency domain parameters during controlled breathing and handgrip exercise either with moxonidine or placebo administration (P > 0.05). Single dose of moxonidine administration increases cardiovagal tone but parasympathetic and sympathetic autonomic maneuvers attenuated its short term effects on HRV in healthy male subjects. (PACE 2010; 929,933) [source] Acute effects of desmin mutations on cytoskeletal and cellular integrity in cardiac myocytesCYTOSKELETON, Issue 2 2003Kurt Haubold Mutations in desmin have been associated with a subset of human myopathies. Symptoms typically appear in the second to third decades of life, but in the most severe cases can manifest themselves earlier. How desmin mutations lead to aberrant muscle function, however, remains poorly defined. We created a series of four mutations in rat desmin and tested their in vitro filament assembly properties. RDM-G, a chimera between desmin and green fluorescent protein, formed protofilament-like structures in vitro. RDM-1 and RDM-2 blocked in vitro assembly at the unit-length filament stage, while RDM-3 had more subtle effects on assembly. When expressed in cultured rat neonatal cardiac myocytes via adenovirus infection, these mutant proteins disrupted the endogenous desmin filament to an extent that correlated with their defects in in vitro assembly properties. Disruption of the desmin network by RDM-1 was also associated with disruption of plectin, myosin, and ,-actinin organization in a significant percentage of infected cells. In contrast, expression of RDM-2, which is similar to previously characterized human mutant desmins, took longer to disrupt desmin and plectin organization and had no significant effect on myosin or ,-actinin organization over the 5-day time course of our studies. RDM-3 had the mildest effect on in vitro assembly and no discernable effect on either desmin, plectin, myosin, or ,-actinin organization in vivo. These results indicate that mutations in desmin have both direct and indirect effects on the cytoarchitecture of cardiac myocytes. Cell Motil. Cytoskeleton 54:105,121, 2003. © 2003 Wiley-Liss, Inc. [source] Acute effects of the antibiotic oxytetracycline on the bacterial community of the grass shrimp, Palaemonetes pugio,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2009Miguel Uyaguari Abstract The toxicity of oxytetracycline (OTC) was evaluated in adult grass shrimp, Palaemonetes pugio. Initially, static acute (96 h) toxicity tests were conducted with shrimp exposed from 0 to 1,000 mg/L OTC. A calculated lethal concentration 50% value of 683.30 mg/L OTC (95% confidence interval 610.85,764.40 mg/L) was determined from these tests, along with a lowest-observable-effect concentration of 750 mg/L and no-observable-effect concentration of 500 mg/L. Moreover, chronic sublethal effects of OTC exposure on grass shrimp intestinal bacterial population were assessed using doses from 0 to 32 mg/L OTC. The total viable counts in digestive tract content had levels between 5.2 and 1 × 104 colony-forming units per gram of tissue at times 0 and 96 h, respectively. Aeromonas hydrophila were the most resistant isolates (27.78%) to OTC exposure. Vibrio alginolyticus showed significant positive growth following exposure to OTC, whereas other bacterial species abundance declined over time. A total of 268 bacterial isolates were screened using antibiotic resistance analysis from a library containing 459 isolates. Among the tested isolates from the OTC treatments, 15.4% were resistant to OTC and 84.6% were OTC sensitive. Oxytetracycline was generally not consistently quantifiable with liquid chromatography-mass spectroscopy technique in shrimp homogenates. The only peak detected was at the 32 mg/L dose of OTC at 96 h. Nevertheless, OTC had a significant biological effect on the bacterial population. Antibiotic resistance to five other antibiotics (penicillin G, sulfathiazole, trimethoprim, trimethoprim and sulfamethoxazole, and tetracycline) was strongly associated with OTC exposures. The present study indicates that OTC toxicity effects in P. pugio and changes in the shrimp microbial community would only be expected under special circumstances. [source] Ecdysteroid synthesis and imaginal disc development in the midge Chironomus riparius as biomarkers for endocrine effects of tributyltinENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2002Torsten Hahn Abstract Acute effects of the endocrine disruptor bis (tri- n -butyltin) oxide (TBTO) on molting-hormone biosynthesis and imaginaldisc development were investigated in larvae of the midge Chironomus riparius (Meigen). Ecdysteroid synthesis was measured by 24-h incubation of molting-hormone-synthesizing tissues (prothoracic glands) in vitro with or without the addition of TBTO. The amount of ecdysteroids produced was analyzed by radioimmunoassay. Developmental effects in vivo were investigated by determining the developmental phase of the genital imaginal discs before and after a 48-h exposure to TBTO in water. Sex-specific effects were found with both endpoints. Ecdysteroid synthesis was significantly reduced (analysis of variance [ANOVA], p , 0.005) in female larvae at all concentrations (TBTO-Sn at 50, 500, and 5,000 ng/L), whereas a significant elevation of the biosynthesis rate occurred in male larvae in the 500-ng/L treatment (ANOVA, p , 0.05). In vivo experiments with development of the genital imaginal disc within a 48-h exposure period revealed a significantly slower development in female larvae and a significantly faster development in male larvae (contingency tables, p , 0.001) at all concentrations tested (TBTO-Sn at 10, 50, 200, and 1,000 ng/L). These results partly coincided with the in vitro effects on molting-hormone synthesis. The 48-h median lethal concentration (LC50) was 25 ,g/L (20,30 ,g/L 95% confidence intervals). The combination of in vitro and in vivo methods has proven to be a useful approach for the detection of endocrine effects of TBTO in C. riparius at levels 2,000-fold below the LC50 value. High sensitivity and short test duration suggest that chironomids may have potential as freshwater sentinel organisms for endocrine-disrupting chemicals. [source] Acute effects of caffeine and tobacco on arterial function and wave travelEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2006J. Swampillai Abstract Background, Caffeine and tobacco consumption are risk factors for heart failure, but their effects remain controversial. It has been hypothesized that they cause alterations in arterial stiffness and arterial wave travel which may increase ventricular loading. In this study the authors examined the influence of these widely used stimulants on wave intensity and arterial stiffness parameters using carotid wave intensity analysis. Materials and methods, A new Doppler-based ultrasound method was used to measure the acute effects of caffeine and tobacco on wave intensity in the right common carotid artery. The measurements enabled changes in arterial stiffness parameters to be recorded. Results, In 17 subjects compared with 10 controls, caffeine increased blood pressure, early systolic wave intensity and wave speed, but late-systolic wave intensity and mid-systolic reflections were unchanged. In 11 smokers studied before and after smoking one cigarette, blood pressure and arterial stiffness increased but wave intensity was unchanged. No changes were observed in the controls. Conclusions, Increased wave intensity during ejection after caffeine suggested sympathomimetic effects on the left ventricular function. Increased wave speed in the common carotid artery implied augmented central loading after caffeine, but the absence of measurable changes in local arterial stiffness in the carotid artery suggested more complex and regional effects. Cigarette smoking acutely increased local arterial stiffness in the common carotid artery. These changes can be detected using wave intensity analysis. [source] Review on the effects of exposure to spilled oils on human healthJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2010Francisco Aguilera Abstract Harmful effects of oil spills on diverse flora and fauna species have been extensively studied. Nevertheless, only a few studies have been compiled in the literature dealing with the repercussions of oil exposure on human health; most of them have focused on acute effects and psychological symptoms. The objective of this work was to gather all these studies and to analyze the possible consequences of this kind of complex exposure in the different aspects of human health. Studies found on this topic were related to the disasters of the Exxon Valdez, Braer, Sea Empress, Nakhodka, Erika, Prestige and Tasman Spirit oil tankers. The majority of them were cross-sectional; many did not include control groups. Acute effects were evaluated taking into account vegetative-nervous symptoms, skin and mucous irritations, and also psychological effects. Genotoxic damage and endocrine alterations were assessed only in individuals exposed to oil from Prestige. The results of the reviewed articles clearly support the need for biomonitoring human populations exposed to spilled oils, especially those individuals involved in the cleanup, in order to evaluate not only the possible immediate consequences for their health but also the medium- and long-term effects, and the effectiveness of the protective devices used. Copyright © 2010 John Wiley & Sons, Ltd. [source] Acute effects of exposure to vapours of standard and dearomatized white spirits in humans.JOURNAL OF APPLIED TOXICOLOGY, Issue 3 2009Abstract A move from ,standard' white spirit (stdWS, 15,20% aromatics) to low-aromatic or dearomatized white spirit (deWS) has been seen, as the latter are considered to carry a smaller risk of health effects. However, data on health risks of deWS on humans are sparse. The aim of this dose-finding study was to identify thresholds of irritation and central nervous system (CNS) effects of the two types of white spirit, as a basis for more detailed studies. Four female and four male healthy volunteers rated symptoms related to irritation, smell and CNS effects on a 0,100 mm visual analogue scale while exposed to increasing levels of deWS or stdWS in eight 10 min steps from 0.5 to 600 mg m,3. Combined ratings of questions related to irritation revealed statistically significant increases compared with pre-exposure ratings at 50 mg m,3 and higher exposures. The ratings increased in a dose-dependent fashion, the medians reaching ,somewhat' for stdWS and ,hardly at all' for deWS. Higher ratings of irritation were found during exposure to stdWS compared with deWS, reaching significance only at 500 mg m,3. The combined ratings of CNS effects reached ,hardly at all', and were significantly increased only for stdWS at 500 and 600 mg m,3. Copyright © 2008 John Wiley & Sons, Ltd. [source] In vivo measurements of T1 relaxation times in mouse brain associated with different modes of systemic administration of manganese chlorideJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2005Yu-Ting Kuo MD Abstract Purpose To measure regional T1 and T2 values for normal C57Bl/6 mouse brain and changes in T1 after systemic administration of manganese chloride (MnCl2) at 9.4 T. Materials and Methods C57Bl/6 mice were anesthetized and baseline T1 and T2 measurements obtained prior to measurement of T1 after administration of MnCl2 at 9.4 T. MnCl2 was administered systemically either by the intravenous (IV), intraperitoneal (IP), or subcutaneous (SC) routes. T1 and T2 maps for each MRI transverse slice were generated using commercial software, and T1 and T2 values of white matter (WM), gray matter (GM), pituitary gland, and lateral ventricle were obtained. Results When compared with baseline values at low-field, significant lengthening of the T1 values was shown at 9.4 T, while no significant change was seen for T2 values. Significant T1 shortening of the normal mouse brain was observed following IV, IP, and SC administration of MnCl2, with IV and IP showing similar acute effects. Significant decreases in T1 values were seen for the pituitary gland and the ventricles 15 minutes after either IV or IP injection. GM showed greater uptake of the contrast agent than WM at 15 and 45 minutes after either IV or IP injections. Although both structures are within the blood-brain barrier (BBB), GM and WM revealed a steady decrease in T1 values at 24 and 72 hours after MnCl2 injection regardless of the route of administration. Conclusion Systemic administration of MnCl2 by IV and IP routes induced similar time-course of T1 changes in different regions of the mouse brain. Acute effects of MnCl2 administration were mainly influenced by either the presence or absence of BBB. SC injection also provided significant T1 change at subacute stage after MnCl2 administration. J. Magn. Reson. Imaging 2005;21:334,339. © 2005 Wiley-Liss, Inc. [source] Acute effects of escalating doses of amiodarone in isolated guinea pig heartsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2002S. BICER Bicer, S., Patchell, J. S., Hamlin, D. M., Hamlin, R. L. Acute effects of escalating doses of amiodarone in isolated guinea pig hearts. J. vet Pharmacol. Therap.25, 221,226. Cardiac effects of escalating concentrations of amiodarone were determined on isolated perfused guinea pig hearts (Langendorff preparations). Spontaneously beating hearts were instrumented for the measurement of RR, PQ, QRS, QT and QTc durations (from a bipolar electrogram), and dP/dtmax and dP/dtmin from an isovolumetric left ventricular pressure curve. Ten hearts were exposed to escalating concentrations of amiodarone (10,7, 10,6, 10,5 and 10,4 M) in dimethyl sulfoxide (DMSO)/Krebs,Henseleit or to DMSO/Krebs,Henseleit (vehicle). Measurements were collected during the last minute of a 15-min concentration. Means of all parameters were compared by ANOVA with repeated measures design. When compared with vehicle, amiodarone prolonged QT and QTc durations at concentrations >10,6 M. The apparent lengthening of RR, PQ and QRS at concentrations >10,6 M did not achieve statistical significance. Similarly, the apparent decreases in dP/dtmax and dP/dtmin at concentrations >10,6 M did not achieve statistical significance. The putative therapeutic concentration of amiodarone is between 2 and 4 × 10,6 M. In this study, at a concentration of 10,6 M, only RR and dP/dtmin tended to change, but they were not different from vehicle. Thus, amiodarone in this preparation has little potential for cardiac toxicity at therapeutic concentrations. [source] Acute effects of methylphenidate on performance during the Test of Variables of Attention in children with attention deficit/hyperactivity disorderPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 3 2007YU-SHU HUANG md Abstract This study attempted to determine the acute effects of methylphenidate (MPH) on cognitive performance using the Test of Variables of Attention (TOVA) in children with attention deficit/hyperactivity disorder (ADHD). The study subjects comprised 57 children diagnosed with ADHD aged 6,13 years. Diagnoses of ADHD and other comorbid psychiatric disorders were based on Diagnostic and Statistical Manual of Mental Disorders-fourth edition criteria following a standard interview with the Schedule for Affective Disorder and Schizophrenia for School-Age Children, epidemiologic version. The subjects' performance on the TOVA was compared before and 1 h after administration of MPH. After administration of MPH, commission scores, response time and ADHD scores improved significantly, however, there were no significant changes in omission scores, response time variability or response sensitivity. The authors concluded that administration of one dose of MPH (0.5,1.0 mg/kg) produced more effects on impulsivity than on attention deficiency in children with ADHD, and that the second half section of the TOVA could be more sensitive than the first half in determining the acute effects of MPH therapy in children with ADHD. However, the effects of different MPH doses on the TOVA results need further investigation. [source] Modulatory effects of static magnetic fields on blood pressure in rabbitsBIOELECTROMAGNETICS, Issue 6 2001Hideyuki Okano Abstract Acute effects of locally applied static magnetic fields (SMF) on pharmacologically altered blood pressure (BP) in a central artery of the ear lobe of a conscious rabbit were evaluated. Hypotensive and vasodilator actions were induced by a Ca2+ channel blocker, nicardipine (NIC). Hypertensive and vasoconstrictive actions were induced by a nitric oxide synthase (NOS) inhibitor, N, -nitro- L -arginine methyl ester (L-NAME). The hemodynamic changes in the artery exposed to SMF were measured continuously and analyzed by penetrating microphotoelectric plethysmography (MPPG). Concurrently, BP changes in a central artery contralateral to that of the exposed ear lobe were monitored. SMF intensity was 1,mT and the duration of exposure was 30,min. A total of 180 experimental trials were carried out in 34 healthy adult male rabbits weighing 2.6,3.8,kg. Six experimental procedures were chosen at random: (1) sham exposure without pharmacological treatment; (2) SMF exposure alone; (3) decreased BP induced by a single intravenous (iv) bolus injection of NIC (100,,M/kg) without SMF exposure; (4) decreased BP induced by injection of NIC with SMF exposure; (5) increased BP induced by a constant iv infusion of L-NAME (10,mM/kg/h) without SMF exposure; (6) increased BP induced by infusion of L-NAME with SMF exposure. The results demonstrated that SMF significantly reduced the vasodilatation with enhanced vasomotion and antagonized the reduction of BP via NIC-blocked Ca2+ channels in vascular smooth muscle cells. In addition, SMF significantly attenuated the vasoconstriction and suppressed the elevation of BP via NOS inhibition in vascular endothelial cells and/or central nervous system neurons. These results suggest that these modulatory effects of SMF on BP might, in part, involve a feedback control system for alteration in NOS activity in conjunction with modulation of Ca2+ dynamics. Bioelectromagnetics 22:408,418, 2001. © 2001 Wiley-Liss, Inc. [source] Acute effects of the sigma-2 receptor agonist siramesine on lens epithelial cellsACTA OPHTHALMOLOGICA, Issue 2007JO KARLSSON Purpose: Experiments were carried out to study the effects of siramesine on markers for apoptosis, oxidative damage and mitochondrial function in primary cultures of human lens epithelial cells (HLEC). Methods: HLEC were incubated with 25 ,M siramesine for 1, 2, 3, 4, 6 and 8 hours. Caspase-3 was assayed in cell extracts with DEVD-AMC. Mitochondrial depolarization was assayed with JC-1. Peroxide production was studied with DCF-DA and superoxide levels with hydroethidium. Glutathione levels were assayed with monochlorobimane. Results: Siramesine induced a significant increase of caspase-3 activity after 6h exposure to 25 ,M siramesine. Nuclear morphology examined with Hoechst 33342 showed signs of apoptosis after the same time intervals. A significant increase in the production of peroxide and superoxide were found up to 4 -8 hours after administration of siramesine. Conclusions: Siramesine, a piperidine analogue, was developed for the treatment of psychiatric disorders and is considered to be relatively nontoxic. This study, and others, indicate effects on cell growth, apoptosis and production of ROS. The sigma-2 receptor may be a regulator of HLEC growth and apoptosis. [source] All-cause mortality and fatal alcohol poisoning in Belarus, 1970,2005DRUG AND ALCOHOL REVIEW, Issue 5 2008YURY E. RAZVODOVSKY Abstract Introduction and Aims. Although alcohol appears to be an important contributor to the burden of disease in the countries of eastern Europe, little systematic research has been undertaken on its impact on mortality in the former Soviet republic of Belarus. There may be a number of factors underlying the particularly negative effect of alcohol on mortality in Belarus, including the pattern of drinking and use of surrogates. A solid body of research and empirical evidence suggests that hazardous patterns of alcohol consumption (binge drinking) lead to quicker and deeper intoxication, increasing the propensity for alcohol-related mortality. Design and Method. To estimate the aggregate level effect of binge drinking on the all-cause mortality rate, trends in the all-cause mortality and fatal alcohol poisoning rates (as a proxy for binge drinking) in Belarus from 1970 to 2005 were analysed employing AutoRegressive Integrated Moving Average (ARIMA) time,series analysis in order to assess a bivariate relationship between the two time,series. Results. The results of time,series analysis suggest a close relationship between all-cause mortality and fatal alcohol poisoning rates at the population level. Conclusions. This study supports the hypothesis that alcohol and all-cause mortality are connected closely in countries where the drinking culture is characterised by heavy drinking episodes and adds to the growing body of evidence that a substantial proportion of total mortality in Belarus is due to acute effects of binge drinking. [source] Testing for cannabis in the work-place: a review of the evidenceADDICTION, Issue 3 2010Scott Macdonald ABSTRACT Background Urinalysis testing in the work-place has been adopted widely by employers in the United States to deter employee drug use and promote ,drug-free' work-places. In other countries, such as Canada, testing is focused more narrowly on identifying employees whose drug use puts the safety of others at risk. Aims We review 20 years of published literature on questions relevant to the objectives of work-place drug testing (WPDT), with a special emphasis on cannabis, the most commonly detected drug. Results We conclude (i) that the acute effects of smoking cannabis impair performance for a period of about 4 hours; (ii) long-term heavy use of cannabis can impair cognitive ability, but it is not clear that heavy cannabis users represent a meaningful job safety risk unless using before work or on the job; (iii) urine tests have poor validity and low sensitivity to detect employees who represent a safety risk; (iv) drug testing is related to reductions in the prevalence of cannabis positive tests among employees, but this might not translate into fewer cannabis users; and (v) urinalysis has not been shown to have a meaningful impact on job injury/accident rates. Conclusions Urinalysis testing is not recommended as a diagnostic tool to identify employees who represent a job safety risk from cannabis use. Blood testing for active tetrahydrocannabinol (THC) can be considered by employers who wish to identify employees whose performance may be impaired by their cannabis use. [source] Acute alcohol impairs conditioning of a behavioural reward-seeking response and inhibitory control processes,implications for addictive disordersADDICTION, Issue 12 2009Sabine Loeber ABSTRACT Aims To investigate whether acute alcohol would affect performance of a conditioned behavioural response to obtain a reward outcome and impair performance in a task measuring inhibitory control to provide new knowledge of how the acute effects of alcohol might contribute to the transition from alcohol use to dependence. Design A randomized controlled between-subjects design was employed. Settings The laboratory of experimental psychology at the University of Sussex. Participants Thirty-two light to moderate social drinkers recruited from the undergraduate and postgraduate population. Measurements After the administration of alcohol (0.8 g/kg) or placebo participants underwent an instrumental reward-seeking procedure, with abstract stimuli serving as S+ (always predicting a win of 10 pence) and S, (always predicting a loss of 10 pence). In addition, a Stop Signal task was administered before and after the administration of alcohol. Findings Participants of the alcohol group performed the behavioural response to obtain the reward outcome more often than placebo subjects in trials associated with loss of money. This finding was observed, although alcohol was not affecting explicit knowledge of stimulus,response outcome contingencies and acquisition of conditioned attentional and emotional responses. In addition, alcohol increased Stop Signal reaction time indicating disinhibiting effects of alcohol, and this was associated positively with response probability to the S,. Conclusions These results demonstrate that alcohol is affecting inhibitory control of behavioural responses to external signals even when associated with punishment, contributing in this way to the transition from alcohol use to dependence. [source] The effects of acute exercise on attentional bias towards smoking-related stimuli during temporary abstinence from smokingADDICTION, Issue 11 2009Kate Janse Van Rensburg ABSTRACT Rationale Attentional bias towards smoking-related cues is increased during abstinence and can predict relapse after quitting. Exercise has been found to reduce cigarette cravings and desire to smoke during temporary abstinence and attenuate increased cravings in response to smoking cues. Objective To assess the acute effects of exercise on attentional bias to smoking-related cues during temporary abstinence from smoking. Method In a randomized cross-over design, on separate days regular smokers (n = 20) undertook 15 minutes of exercise (moderate intensity stationary cycling) or passive seating following 15 hours of nicotine abstinence. Attentional bias was measured at baseline and post-treatment. The percentage of dwell time and direction of initial fixation was assessed during the passive viewing of a series of paired smoking and neutral images using an Eyelink II eye-tracking system. Self-reported desire to smoke was recorded at baseline, mid- and post-treatment and post-eye-tracking task. Results There was a significant condition × time interaction for desire to smoke, F(1,18) = 10.67, P = 0.004, eta2 = 0.36, with significantly lower desire to smoke at mid- and post-treatment following the exercise condition. The percentage of dwell time and direction of initial fixations towards smoking images were also reduced significantly following the exercise condition compared with the passive control. Conclusion Findings support previous research that acute exercise reduces desire to smoke. This is the first study to show that exercise appears to also influence the salience and attentional biases towards cigarettes. [source] Effect of isometric exercise and body scanning on cigarette cravings and withdrawal symptomsADDICTION, Issue 7 2009Michael Ussher ABSTRACT Aims To examine the acute effects of a guided relaxation routine (body scan) and isometric exercise on desire to smoke and tobacco withdrawal symptoms. Design Experimental comparison of three conditions. Participants Forty-eight individuals reporting smoking ,10 cigarettes daily. Intervention Random assignment to one of three interventions delivered via a 10-minute audio: isometric exercise (IE, n = 14), body scanning (BS, n = 18) or a reading about natural history (control group, n = 16). Interventions were delivered twice on the same day: in the laboratory, then in their ,normal' environment. Measurements Desire to smoke (primary outcome) and withdrawal symptoms were rated at pre-intervention and up to 30 minutes post-intervention. Findings Controlling for baseline scores, post-intervention desire to smoke and withdrawal symptoms were significantly lower for IE and BS groups, compared with the controls, in both environments. There were no significant differences for IE versus BS. For desire to smoke, controlling for baseline values, ratings in the laboratory were significantly lower for IE and BS versus the control up to 30 minutes post-intervention. In the normal environment, these ratings were significantly lower only up to 5 minutes post-intervention. Conclusions Brief IE and BS interventions are effective for reducing desire to smoke and withdrawal symptoms in temporarily abstaining smokers. These interventions were found to be more effective in the laboratory than in the smoker's normal environment, but this may be an artefact of there not being a sufficient ,wash-out' period between interventions. These techniques may be beneficial for managing desire to smoke and tobacco withdrawal. [source] First report of saxitoxin in Finnish lakes and possible associated effects on human healthENVIRONMENTAL TOXICOLOGY, Issue 3 2005Jarkko Rapala Abstract This study is the first report of saxitoxin in cyanobacterial blooms in Finland. Bloom samples (n = 50) were collected from Finnish freshwater sites during summer months of 2002 and 2003. These samples were screened for the presence of paralytic shellfish toxins (PSTs) using the Jellett rapid PSP screening test. Samples testing positive for PSTs (n = 7) were further analyzed with saxiphilin- and voltage-gated sodium channel [3H]-STX,binding radioreceptor assays and liquid chromatography using fluorescence and mass spectrometric analysis. The results indicated that saxitoxin (STX) was the only PST analogue in the samples and that it was present in high concentrations, as much as 1 mg L,1. Microscopic analysis revealed that 95%,100% of the phytoplankton in the positive samples consisted of Anabaena lemmermannii. The trophic status of lakes in which STX-containing blooms were found varied from oligotrophic to hypertrophic. All the lakes had high nitrogen-to-phosphorus ratios. In some instances, samples had been collected from sites where swimmers had reported adverse health effects, and in three such cases, reported adverse health effects were associated with sites from which samples testing positive for STX had been received. Symptoms of fever, eye irritation, abdominal pains, and skin rash were reported in children aged 2,10 years after exposure to the water. These were not the adverse human symptoms typical of STX poisoning; rather, they represented acute effects often reported following recreational exposure to cyanobacterial blooms. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 331,340, 2005 [source] Comparison of hardness- and chloride-regulated acute effects of sodium sulfate on two freshwater crustaceansENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2007David John Soucek Abstract Based on previous observations that hardness (and potentially chloride) influences sodium sulfate toxicity, the objective of the current study was to quantify the influence of both chloride and water hardness on acute toxicity to Hyalella azteca and Ceriodaphnia dubia. In addition, observed toxicity data from the present study were compared to toxicity predictions by the salinity/toxicity relationship (STR) model. Hardness had a strong influence on sulfate toxicity that was similar for both crustaceans, and nearly identical median lethal concentration (LC50)/hardness slopes were observed for the two species over the tested range. Chloride had a strong but variable influence on sulfate acute toxicity, depending on the species tested and the concentration range. At lower chloride concentrations, LC50s for H. azteca strongly were correlated positively with chloride concentration, although chloride did not affect the toxicity of sodium sulfate to C. dubia. The opposite trend was observed over the higher range of chloride concentrations where there was a negative correlation between chloride concentration and sulfate LC50 for both species. The widely ranging values for both species and a high correlation between LC50s in terms of sulfate and conductivity suggested that, whether based on sulfate, conductivity, or total dissolved solids (TDS), attempts at water quality standard development should incorporate the fact that water quality parameters such as hardness and chloride strongly influence the toxicity of high TDS solutions. The STR model predicted toxicity to C. dubia relatively well when chloride was variable and hardness fixed at approximately 100 mg/L; however, the model did not account for the protective effect of hardness on major ion/TDS toxicity. [source] Influence of developmental stage on sensitivity to ammonium nitrate of aquatic stages of amphibiansENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006Manuel E. Ortiz-Santaliestra Abstract In static renewal experiments, we studied how developmental stage influences the effect of ammonium nitrate on embryonic and larval stages of anuran amphibians. The observed lethal effects caused by ammonium nitrate increased with both concentration and duration of exposure. Significant differences were observed in sensitivity to ammonium nitrate as a function of developmental stage in Discoglossus galganoi, Pelobates cultripes, and Bufo calamita. In D. galganoi and P. cultripes, younger individuals displayed greater acute effects from the chemical fertilizer compared with older individuals. For example, 100% of P. cultripes hatchlings died after 4 d of exposure to a nominal concentration of 225.8 mg N-NO3NH4/L, whereas less than 40% of individuals from older larval stages died when exposed to this concentration. A delay of 4 d in the beginning of the exposure to the chemical was enough to cause significant differences in sensitivity. Bufo calamita showed a higher sensitivity in later larval stages after 12 d of exposure. Hyla meridionalis and B. calamita were less sensitive than the other two species. Peak ammonium nitrate concentrations usually occur when amphibians are breeding and, thus, when the most sensitive aquatic stage is in the water. The developmental stage of the test animals should be considered when evaluating the risk of ammonium nitrate to amphibians. [source] Acute and chronic toxicity of imidazolium-based ionic liquids on Daphnia magnaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2005Randall J. Bernot Abstract Room-temperature ionic liquids (ILs) are considered to be green chemicals that may replace volatile organic solvents currently used by industry. However, IL effects on aquatic organisms and ecosystems are currently unknown. We studied the acute effects of imidazolium-based ILs on survival of the crustacean Daphnia magna and their chronic effects on number of first-brood neonates, total number of neonates, and average brood size. Lethal concentrations of imidazolium ILs with various anions (X,) ranged from a median lethal concentration (LC50) of 8.03 to 19.91 mg L,1, whereas salts with a sodium cation (Na+ X,) were more than an order of magnitude higher (NaPF6 LC50, 9,344.81 mg L,1; NaBF4 LC50, 4765.75 mg L,1). Thus, toxicity appeared to be related to the imidazolium cation and not to the various anions (e.g., CI,, Br,, PF,6, and BF,4). The toxicity of imidazolium-based ILs is comparable to that of chemicals currently used in manufacturing and disinfection processes (e.g., ammonia and phenol), indicating that these green chemicals may be more harmful to aquatic organisms than current volatile organic solvents. We conducted 21-d chronic bioassays of individual D. magna exposed to nonlethal IL concentrations at constant food-resource levels. Daphnia magna produced significantly fewer total neonates, first-brood neonates, and average neonates when exposed to lower concentrations (0.3 mg L,1) of imidazolium-based ILs than in the presence of Na-based salts at higher concentrations (400 mg L,1). Such reductions in the reproductive output of Daphnia populations could cascade through natural freshwater ecosystems. The present study provides baseline information needed to assess the potential hazard that some ILs may pose should they be released into freshwater ecosystems. [source] Predicting the toxicity of chromium in sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2004Walter J. Berry Abstract Chromium exists in sediments in two oxidation states: Cr(III), which is relatively insoluble and nontoxic, and Cr(VI), which is much more soluble and toxic. Chromium(VI) is thermodynamically unstable in anoxic sediments, and acid-volatile sulfide (AVS) is formed only in anoxic sediments; therefore sediments with measurable AVS concentrations should not contain toxic Cr(VI). If this hypothesis holds true, measuring AVS could form the basis for a theoretically based guideline for Cr in sediments. Ten-day water-only and spiked sediment toxicity tests with the amphipod Ampelisca abdita were performed with Cr(VI) and Cr(III), along with sediments collected from a site contaminated with high concentrations of Cr. In sediments where AVS exceeded analytical detection limits, Cr concentrations in interstitial water were very low (<100 ,g/L) and no significant toxicity to A. abdita was observed. In sediments in which AVS was not significantly greater than zero, Cr concentrations in interstitial waters increased significantly, with greater than 90% of the Cr present as Cr(VI), and mortality of A. abdita was elevated. These results demonstrate that measurements of AVS and interstitial water chromium can be useful in predicting the absence of acute effects from Cr contamination in sediments. [source] Pregabalin Exerts Oppositional Effects on Different Inhibitory Circuits in Human Motor Cortex: A Double-blind, Placebo-controlled Transcranial Magnetic Stimulation StudyEPILEPSIA, Issue 5 2006Nicolas Lang Summary:,Purpose: To explore acute effects of pregabalin (PGB) on human motor cortex excitability with transcranial magnetic stimulation (TMS). Methods: PGB, 600 mg/day, was orally administered in 19 healthy subjects twice daily in a randomized, double-blind, placebo-controlled crossover design. Several measures of motor cortex excitability were tested with single- and paired-pulse TMS. Results: Mean short-interval intracortical inhibition (SICI) was reduced after PGB (74 ± 7% of unconditioned response) compared with placebo (60 ± 6% of unconditioned response). In contrast, mean long-interval intracortical inhibition (LICI) was increased by PGB (26 ± 4% of unconditioned response) compared with placebo (45 ± 8% of unconditioned response), and mean cortical silent period (CSP) showed an increase from 139 ± 8 ms or 145 ± 8 ms after placebo to 162 ± 7 ms or 161 ± 10 ms after PGB. Motor thresholds, intracortical facilitation, and corticospinal excitability were unaffected. Conclusions: The observed excitability changes with oppositional effects on SICI and LICI or CSP suggest ,-aminobutyric acid (GABA)B -receptor activation. They are markedly distinct from those induced by gabapentin, although both PGB and gabapentin are thought to mediate their function by binding to the ,(2)-, subunit of voltage-gated calcium channels. Conversely, the TMS profile of PGB shows striking similarities with the pattern evoked by the GABA-reuptake inhibitor tiagabine. [source] The Relative Influence of Epileptic EEG Discharges, Short Nonconvulsive Seizures, and Type of Epilepsy on Cognitive FunctionEPILEPSIA, Issue 1 2004Albert Aldenkamp Summary: Purpose: This study addressed whether cognitive impairment in children with epilepsy is caused by disease-related stable factors, such as the type of epilepsy, or by acute effects of paroxysmal epileptic activity such as epileptic EEG discharges. We studied a nonselected group with short nonconvulsive seizures, as these seizures may elude detection and may therefore persist over a longer period. In this group, the diagnostic issue is to differentiate between the combined effects of several epilepsy-related factors on cognition. Methods: All children were assessed with 32-channel EEG, synchronized with a computerized cognitive test system and a video-monitoring system. Recording time was 2 h. The primary inclusion criteria were unclear seizures and fluctuations in cognitive performance and/or frequent epileptic EEG discharges in a recent EEG. Results: One hundred fifty-two patients met the inclusion criteria; 31 patients appeared not to have a diagnosis of epilepsy and were used as a nonepilepsy control group. Our results show that type of epilepsy has an impact on stable cognitive functions, such as educational achievement. Paroxysmal epileptic activity (acute effects of seizures and epileptic EEG discharges) affects primarily transient mechanistic cognitive processes (alertness, mental speed). Conclusions: These results suggest that the effects of paroxysmal epileptic activity on transient cognitive mechanisms may accumulate over time and consequently affect the more stable aspects of cognitive function such as educational achievement. The clinical relevance is that early detection of the cognitive impact of seizure-related activity and subsequent treatment may prevent its detrimental impact on cognitive and educational development. [source] Acute effects of caffeine and tobacco on arterial function and wave travelEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2006J. Swampillai Abstract Background, Caffeine and tobacco consumption are risk factors for heart failure, but their effects remain controversial. It has been hypothesized that they cause alterations in arterial stiffness and arterial wave travel which may increase ventricular loading. In this study the authors examined the influence of these widely used stimulants on wave intensity and arterial stiffness parameters using carotid wave intensity analysis. Materials and methods, A new Doppler-based ultrasound method was used to measure the acute effects of caffeine and tobacco on wave intensity in the right common carotid artery. The measurements enabled changes in arterial stiffness parameters to be recorded. Results, In 17 subjects compared with 10 controls, caffeine increased blood pressure, early systolic wave intensity and wave speed, but late-systolic wave intensity and mid-systolic reflections were unchanged. In 11 smokers studied before and after smoking one cigarette, blood pressure and arterial stiffness increased but wave intensity was unchanged. No changes were observed in the controls. Conclusions, Increased wave intensity during ejection after caffeine suggested sympathomimetic effects on the left ventricular function. Increased wave speed in the common carotid artery implied augmented central loading after caffeine, but the absence of measurable changes in local arterial stiffness in the carotid artery suggested more complex and regional effects. Cigarette smoking acutely increased local arterial stiffness in the common carotid artery. These changes can be detected using wave intensity analysis. [source] Enhanced external counterpulsation improves skin oxygenation and perfusionEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2004M. J. Hilz Abstract Background, Enhanced external counterpulsation (EECP) augments diastolic and reduces systolic blood pressures. Enhanced external counterpulsation has been shown to improve blood flow in various organ systems. Beneficial effects on skin perfusion might allow EECP to be used in patients with skin malperfusion problems. This study was performed to assess acute effects of EECP on superficial skin blood flow, transdermal oxygen and carbon dioxide pressures. Materials and methods, We monitored heart rate, blood pressure, transdermal blood flow as well as oxygen and carbon dioxide pressures in 23 young, healthy persons (28 ± 4 years) and 15 older patients (64 ± 7 years) with coronary artery disease before, during and 3 min after 5 min EECP. Friedman test was used to compare the results of 90-s epochs before, during and after EECP. Significance was set at P < 0·05. Results, Enhanced external counterpulsation increased heart rate and mean blood pressure. During EECP, transdermal oxygen pressure and concentration of moving blood cells increased while transdermal carbon dioxide pressure and velocity of moving blood cells decreased significantly in both groups. After EECP, transdermal carbon dioxide pressure was still reduced while the other parameters returned to baseline values. Conclusions, Improved skin oxygenation and carbon dioxide clearance during EECP seem to result from the increased concentration and reduced flow velocity, i.e. prolonged contact time, of erythrocytes. The increased concentration of moving blood cells and the decreased velocity of moving blood cells at both tested skin sites indicate peripheral vasodilatation. [source] | ||||||||||||||||||||||||||||||||||||||||