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La
Kinds of La Terms modified by La Selected AbstractsHypersensitivity to local anaesthetics , update and proposal of evaluation algorithmCONTACT DERMATITIS, Issue 2 2008Jacob Pontoppidan Thyssen Local anaesthetics (LA) are widely used drugs. Adverse reactions are rare but may be caused by delayed-type hypersensitivity reactions and probably also immediate-type reactions. As it is not always easy to clinically differ between these subtypes, allergy skin testing should be considered. Although numerous test protocols have been published, how patients with hypersensitivity reactions to LA are ideally evaluated remains a topic of discussion. This review attempts to generate a comprehensive update on allergic reactions to LA and to present an algorithm that can be used for the evaluation of patients suspected with immediate- and delayed-type immune reactions. Literature was examined using PubMed-Medline, EMBASE, Biosis and Science Citation Index. Based on the literature, the proposed algorithm may safely and rapidly distinguish between immediate-type and delayed-type allergic immune reactions. [source] Comments on papers reporting IR-spectra and other data of alleged L-alanine alaninium nitrate and L-alanine sodium nitrate crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2009M. Fleck Abstract We argue that the IR- and Raman-spectra of "L-alanine alaninium nitrate" given in "Investigation on the growth, optical behaviour and factor group of an NLO crystal: L-Alanine Alaninium nitrate" by Aravindan et al., Cryst. Res. Technol. 42, 1097 (2007), actually concern L-Alanine. Correspondingly, the data presented in "A comparative study on the growth and characterization of nonlinear optical amino acid crystals: L-Alanine (LA) and L-alanine alaninium nitrate (LAAN)" by Aravindan et al., Spectrochim. Acta A 71, 297 (2008), seems to be erroneous, as is "Synthesis, Growth, and Characterization of a New Semiorganic Nonlinear Optical Crystal: L-Alanine Sodium Nitrate (LASN)", Sethuraman, et al., Cryst. Growth Des. 8, 1863 (2008). In these papers properties and data were reported for L-Alanine compounds that actually are L-Alanine crystals and, in addition, unit cell parameters were given that seem to have been copied from other papers. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] 5-Hydroxytryptamine-induced microvascular pressure transients in lungs of anaesthetized rabbitsACTA PHYSIOLOGICA, Issue 2 2001N. Sen We determined lung microvascular pressure transients induced by 5-hydroxytryptamine (5HT), by the micropuncture technique. We mechanically ventilated anaesthetized (halothane 0.8%), open-chested rabbits, in which we recorded pulmonary artery (PA), left atrial (LA) and carotid artery pressures and cardiac output. For 4-min periods of stopped ventilation, we constantly inflated the lung with airway pressure of 7 cmH2O, then micropunctured the lung to determine pressures in arterioles and venules of 20,25 ,m diameter. An intravenous bolus infusion of 5HT (100 ,g), increased total pulmonary vascular resistance by 59%. Prior to 5HT infusion, the arterial, microvascular and venous segments comprised 30, 50 and 19% of the total pulmonary vascular pressure drop, respectively. However 14 s after 5HT infusion, the PA-arteriole pressure difference (arterial pressure drop) increased 46%, while the venule-LA pressure difference (venous pressure drop) increased >100%. The arteriole,venule pressure difference (microvascular pressure drop) was abolished. The increase in the arterial pressure drop was maintained for 4.8 min, whereas the increased venous pressure drop reverted to baseline in <1 min. We conclude that in the rabbit lung in situ, a 5HT bolus causes sustained arterial constriction and a strong but transient venous constriction. [source] Effect of combined supplementation with vitamin E and alpha-lipoic acid on myocardial performance during in vivo ischaemia-reperfusionACTA PHYSIOLOGICA, Issue 4 2000Coombes Reactive oxygen species (ROS) contribute significantly to myocardial ischaemia-reperfusion (I-R) injury. Recently the combination of the antioxidants vitamin E (VE) and alpha-lipoic acid (, -LA) has been reported to improve cardiac performance and reduce myocardial lipid peroxidation during in vitro I-R. The purpose of these experiments was to investigate the effects of VE and , -LA supplementation on cardiac performance, incidence of dysrhythmias and biochemical alterations during an in vivo myocardial I-R insult. Female Sprague,Dawley rats (4-months old) were assigned to one of the two dietary treatments: (1) control diet (CON) or (2) VE and , -LA supplementation (ANTIOXID). The CON diet was prepared to meet AIN-93M standards, which contains 75 IU VE kg,1 diet. The ANTIOXID diet contained 10 000 IU VE kg,1 diet and 1.65 g , -LA kg,1 diet. After the 14-week feeding period, significant differences (P < 0.05) existed in mean myocardial VE levels between dietary groups. Animals in each experimental group were subjected to an in vivo I-R protocol which included 25 min of left anterior coronary artery occlusion followed by 10 min of reperfusion. No group differences (P > 0.05) existed in cardiac performance (e.g. peak arterial pressure or ventricular work) or the incidence of ventricular dysrhythmias during the I-R protocol. Following I-R, two markers of lipid peroxidation were lower (P < 0.05) in the ANTIOXID animals compared with CON. These data indicate that dietary supplementation of the antioxidants, VE and , -LA do not influence cardiac performance or the incidence of dysrhythmias but do decrease lipid peroxidation during in vivo I-R in young adult rats. [source] The role of cell death in sexually dimorphic muscle development: Male-specific muscles are retained in female bax/bak knockout miceDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2008Dena A. Jacob Abstract The bulbocavernosus (BC) and levator ani (LA) muscles are present in males but absent or severely reduced in females, and the fate of these muscles controls the survival of motoneurons in the sexually dimorphic spinal nucleus of the bulbocavernosus. However, the mechanism underlying the sex difference in BC and LA development has been controversial. We examined the role of cell death in sexual differentiation of the bulbocavernosus BC/LA muscles in mice. Muscle development was mapped from embryonic day 16 (E16) to postnatal day 5 (P5). A sex difference (male > female) first arose on E17 (BC) or E18 (LA), and increased in magnitude postnatally. TUNEL labeling revealed dying cells in the BC and LA muscles of both sexes perinatally. However, females had a significantly higher density of TUNEL-positive cells than did males. A role for the proapoptotic factors, Bax and Bak, in BC/LA development was tested by examining mice lacking one or both of these proteins. In females lacking either Bax or Bak, the BC was absent and the LA rudimentary. Deletion of both bax and bak genes, however, rescued the BC, increased LA size ,20-fold relative to controls, and virtually eliminated TUNEL-positive cells in both muscles. We conclude that cell death plays an essential role in sexual differentiation of the BC/LA muscles. The presence of either Bax or Bak is sufficient for cell death in the BC/LA, whereas the absence of both prevents sexually dimorphic muscle cell death. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source] ,-Lipoic acid reduces congenital malformations in the offspring of diabetic miceDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 3 2009Y. Sugimura Abstract Background The mechanism of diabetes-induced congenital malformation remains to be elucidated. It has been reported that ,-lipoic acid (LA) prevents neural tube defects (NTDs) in offsprings of rats with streptozotocin-induced diabetes. Here, we evaluate the protective effect of LA against diabetic embryopathy, including NTDs, cardiovascular malformations (CVMs), and skeletal malformations, in mice. Methods Female mice were rendered hyperglycemic using streptozotocin and then mated with normal male mouse. Pregnant diabetic or non-diabetic mice were treated daily with either LA (100 mg/kg body weight) or saline between gestational days 0 and 18. On day 18, fetuses were examined for congenital malformations. Results Plasma glucose levels on day 18 were not affected by LA treatment. No congenital malformations were observed either in the saline-treated or LA-treated non-diabetic group. In the saline-treated diabetic group, 39% of fetuses had external malformations and 30% had NTDs. In the LA-treated diabetic group, the corresponding proportions were 11 and 8%, respectively. LA treatment also decreased the incidence of CVMs from 30,3% and of skeletal malformations from 29,6%. Conclusions We conclude that LA can reduce NTDs, CVMs and skeletal malformations in the offspring of diabetic mice at term delivery. Copyright © 2009 John Wiley & Sons, Ltd. [source] Natural disasters and older US adults with disabilities: implications for evacuationDISASTERS, Issue 1 2007Lisa C. McGuire PhD We analysed 2003 and 2004 Behavioral Risk Factor Surveillance System (BRFSS) data from New Orleans-Metairie-Kenner, LA to produce estimates of the number of community dwelling people aged 65 years or older with a disability and requiring special equipment., Approximately, 47,840 (31.6 per cent) older adults with a disability and 24,938 (16.6 per cent) older adults requiring the use of special equipment were community dwelling and might require assistance to evacuate or a shelter that could accommodate special equipment. Older adults who need special equipment were likely to be female, unmarried and white, and to rate their health as fair or poor. Personnel who plan and prepare for evacuations and temporary shelter during disasters need baseline information on the number of older adults with a disability or who require special equipment. A surveillance system, such as the BRFSS, gathers information that planners can use to prepare for and to deliver services. [source] Is the Presence of Mitral Annular Calcification Associated with Poor Left Atrial Function?ECHOCARDIOGRAPHY, Issue 8 2009Vignendra Ariyarajah M.D. Introduction: Mitral annular calcification (MAC) is characterized by calcium and lipid deposition in the annular fibrosa of the mitral valve. MAC is associated with cardiovascular events but little is known of its association with left atrial (LA) function. Methods: We prospectively obtained 12-lead electrocardiograms (ECGs) and transthoracic echocardiograms (TTE) on patients scheduled for nonemergent echocardiographic assessment at a tertiary care hospital. MAC was graded as 0 = none, 1 = mild, 2 = moderate, 3 = severe. LA linear and volume measurements (stroke volume, LA passive emptying fraction, LA active emptying fraction and LA kinetic energy) were done specifically in addition to commonly measured TTE parameters. Results: From the 124 considered for the study, 72 patients remained (aged 68±18 years; 44% male) after excluding those with poor ECG tracings and/or poor TTE images. Eighteen patients had MAC; mild MAC = 14, moderate MAC = 3, severe MAC = 1. When patients with MAC were compared to those without MAC, no significant difference was noted, except for LA linear dimension index (2.1±0.4 vs. 1.9±0.3 cm/m2; P = 0.03). For those with mild and moderate MAC, a trend was noted toward lower LA function with increasing MAC severity. In addition, significant differences were noted between those with and without interatrial conduction delay, where those with such delay had significantly impaired LA stroke volume (9.8±3 vs. 19.93±4 ml; P < 0.0001), LA active emptying fraction (18.83±8 vs. 65.71±9%; P < 0.0001) and LA total/reservoir fraction (39.54±6 vs. 75.1±6%; P < 0.0001). Conclusions: MAC is associated with increase in LA linear dimension on TTE and may be equally represented with lower overall LA function. Further study in a much larger cohort is warranted to delineate these and other potential associations of MAC. [source] Clinical Assessment and Rest and Stress Echocardiography for Prediction of Long-Term Prognosis in African Americans with Known or Suspected Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 5 2009Stephen G. Sawada M.D. Background: There is limited information on noninvasive risk stratification of African Americans, a high-risk group for cardiovascular events. We investigated the value of clinical assessment and echocardiography for the prediction of a long-term prognosis in African Americans. Methods: Dobutamine echocardiography was performed in 324 African Americans. Two-dimensional measurements were performed at rest, and rest and stress wall motion was assessed. A retrospective follow-up was conducted for cardiac events: myocardial infarction (MI) or cardiac death (CD). Results: The mean age was 59 ± 12 years, and 83% of patients had hypertension. The follow-up was obtained in 318 (98%) patients for a mean of 5.3 years. The events occurred in 107 (33%) subjects. The independent predictors of events were history of MI (P = 0.001, risk ratio [RR] 2.04), ischemia (P = 0.007, RR 1.97), fractional shortening (P = 0.033, RR 0.08), and left atrial (LA) dimension (P = 0.034, RR 1.39). An LA size of 3.6 cm and a fractional shortening of 0.30 were the best cutoff values for the prediction of events. Prior MI, ischemia, LA size >3.6 cm, and fractional shortening <0.30 were each considered independent risk predictors for events. The event rates were 13%, 21%, 38%, 59%, and 57% in patients with 0, 1, 2, 3, and 4 risk predictors, respectively. Event-free survival progressively worsened with an increasing number of predictors: 0 or 1 versus 2 predictors, P < 0.001; 2 versus 3 or 4 predictors, P = 0.003. Conclusion: The long-term prognosis of African Americans can be accurately predicted by clinical assessment combined with rest and stress echocardiography. [source] Effect of Alcohol-Induced Septal Ablation on Left Atrial Volume and Ejection Fraction Assessed by Real Time Three-Dimensional Transthoracic Echocardiography in Patients with Hypertrophic CardiomyopathyECHOCARDIOGRAPHY, Issue 7 2008Fadi G. Hage M.D. Alcohol-induced septal ablation (AISA) is an accepted treatment for hypertrophic cardiomyopathy (HCM) patients with left ventricular (LV) outflow obstruction who are unresponsive to medical therapy. As left atrial (LA) enlargement has been correlated with increased morbidity and mortality in HCM, we assessed LA volumes and ejection fraction (EF) prior to and after AISA using real time three-dimensional (3D) transthoracic echocardiography (TTE) in 12 patients (9 women; mean age 52 ± 15 years; 11 Caucasian). All patients underwent successful AISA with no complications and their resting left ventricular outflow gradients decreased from 40.5 ± 22.2 to 9.1 ± 17.6 mmHg (P < 0.001) while their gradients with provocation decreased from 126.2 ± 31.7 to 21.8 ± 28.0 mmHg (P < 0.001). All patients showed improvements in their New York Heart Association (NYHA) functional class. Both the LA end-systolic (45.2 ± 12.9 to 37.2 ± 13.7 ml, P < 0.0001) and end-diastolic (79.6 ± 18.9 to 77.1 ± 18.6 ml, P = 0.001) volumes decreased after AISA. The LA EF increased from 43.1 ± 9.0 to 52.5 ± 8.8% (P = 0.001). The increase in LA EF correlated with the decrease in the resting left ventricular outflow gradient (R =,0.647, P = 0.03). In conclusion, 3D echocardiography can be utilized to follow LA function after AISA for HCM. AISA results in clinical improvement in patients with HCM and in improvement of LA EF that is correlated with the decrease in the left ventricular outflow gradient. [source] Age- and Sex-Related Differences in the Tissue Doppler Imaging Parameters of Left Ventricular Diastolic DysfunctionECHOCARDIOGRAPHY, Issue 6 2007Hyeun S. Park M.D. Background: The effect of age and gender on tissue Doppler imaging measurements comparing the septal and mitral annulus needs to be investigated. Methods: We investigated in 276 outpatients in a university cardiology practice the relationship of age and gender to left atrial (LA) size, LA volume, mitral pulse-wave Doppler E/A ratio, E/Ea ratios by tissue Doppler image of mitral annular velocity (TDI), and left ventricular diastolic dysfunction (LVDD) by TDI. Results: Mitral E/A inflow was statistically decreased with age. E/Ea ratios of the lateral and mean of both lateral and septal annulus showed a statistical increase with age, while the E/Ea ratio of the septal annulus did not correlate with age. When comparing men and women of all ages, the mean LA volume for men was 59.2 cm3± 24.36 cm3 versus 48.54 cm3± 16.14 cm3 (P-value < 0.0001) and the mean LA size was 4.0 + 0.51 cm for men and 3.65 + 0.47 for women (P-value < 0.0001). There was no statistical difference between men and women when looking at mitral E/A inflow ratio, deceleration time, E/Ea ratio of the septal annulus, E/Ea ratio of the lateral annulus, E/Ea ratio of the mean of both septal and lateral annulus, and grades of LVDD. Conclusion: In patients 70 years of age or older, the mean diastolic grade was mild-to-moderate LVDD when using lateral or mean of septal and lateral annular measurements. When only the septal annular measurements were used to determine diastolic grade, all four age groups showed a mean of mildly to moderately impaired LVDD and showed no correlation with age. There were no differences in tissue Doppler imaging measurements between men and women. [source] ORIGINAL INVESTIGATIONS: Comparison of Left Atrial Dimensions by Transesophageal and Transthoracic EchocardiographyECHOCARDIOGRAPHY, Issue 10 2005Harshinder Singh M.D. Transesophageal echocardiography (TEE) is an established cardiovascular diagnostic technique. Left atrial (LA) size, as measured by transthoracic echocardiography (TTE), is associated with cardiovascular disease and is a risk factor for atrial fibrillation, stroke, death, and the success of cardioversion. Assessment of LA size has not been as well validated on TEE as on TTE. We determined LA size measurements in four standard views in 122 patients undergoing TEE and TTE at the same setting. In this study, we found that measurement of LA dimensions by TEE suffers from significant limitations in all views except the basal long-axis view (mid-esophageal level) with transducer plane at 120,150 degrees. This view had the best correlation with transthoracic LA measurements: r = 0.79 for TEE long axis (CI 0.71,0.85), P <.0001. (ECHOCARDIOGRAPHY, Volume 22, November 2005) [source] Analysis of Left Atrial Volume Change Rate for Evaluation of Left Ventricular Diastolic FunctionECHOCARDIOGRAPHY, Issue 7 2004F.E.S.C., Ming-Jui Hung M.D. An excellent correlation exists between the change in the left atrial (LA) angiographic area and posterior aortic wall motion. The aim of the study was to define the role of posterior aortic wall motion, indicating LA volume change, during the left ventricular (LV) phase for the assessment of LV diastolic function. A total of 155 patients underwent echocardiography after cardiac catheterization. Study patients were classified into four groups according to the ratio of early-to-late transmitral flow velocity (E/A ratio) and/or LV end-diastolic pressure (EDP): 42 patients with LVEDP < 15 mmHg and E/A ratio >1 (normal filling); 46 patients with E/A < 1 (impaired relaxation); 46 patients with LVEDP , 15 mmHg and E/A > 1 and <2 (pseudonormal filling); 21 patients with E/A > 2, E , 70 cm/s, and E-wave deceleration time ,160 ms (restrictive filling). The slopes of early and late (slopes E and A) diastolic motion of LA wall were derived from M-mode analysis, together with the LV isovolumic time constant Tau from cardiac catheterization. Values of slope E/A decreased in restrictive filling, pseudonormal filling, and impaired relaxation as compared with normal filling (0.41 ± 0.14, 0.69 ± 0.15, and 0.56 ± 0.23 vs 1.25 ± 0.26, P < 0.001, respectively) and correlated inversely with the isovolumic time constant Tau (r = 0.79, P < 0.001). In cases for which a value of slope E/A < 1 was obtained, indicating a relaxation abnormality, the M-mode derived pattern of LA wall motion identified the underlying abnormal LV diastolic function with a sensitivity of 98.3%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 95.2%. Analysis of the slope of LA wall motion, indicating LA volume change rate, during LV diastolic phase is useful in evaluating LV diastolic function. It provides a new noninvasive index that correlates well with invasive index of LV relaxation. [source] EFFECT OF PARAPROSTHETIC MODERETE TO SEVERE MITRAL REGURGITATION ON EMBOLIC EVENTS IN PATIENTS WITH PROSTHETIC MITRAL VALVESECHOCARDIOGRAPHY, Issue 5 2004C. Cevik Thromboembolism is the major chronic risk for patients with mechanical prosthetic heart valves. Although optimal oral anticoagulantion is the key determinant for embolic events (EE) in these patients; other factors also contribute to this complication. We studied the prevalence and determinants of embolic events in patients with mitral prosthetic heart valves undergoing transesophageal echocardiography (TEE). 210 patients (86 male and 124 female, mean age 45.1 +/, 9.6 years) underwent a TEE study for evaluation of prosthetic valve functions. Clinical and TEE findings of the patients were as follows: Atrial fibrillation in 132 (%62) patients, prosthetic valve thrombus in 55 (%26) suboptimal INR (INR < 1.8) in 61 (%29) pts, left atrial spontenous echocardiographic contrast (SEC) in 31 (%14) patients, paraprosthetic moderete-severe mitral regurgitation (MR) in 28 (%13), left atrial (LA) and/or left atrial appendix (LAA) thrombus in 41 (%19), LA and/or LAA outflow velocities <0.25 m/sn in 21 patiens (%10), left atrial diameter >6 cm in 47 (%22). 72 patients had a history of EE in the previous 6 months (%34). In no patients were there any EE in the presence of paraprosthetic moderate to severe MR. Both with univariate and multivariate analysis presence of prosthetic valve and LA and/or LAA thrombus, absence of paraprosthetic moderete-severe MR, suboptimal INR, atrial fibrillation were found to be independent predictors for embolic events. Conclusions: Although the presence of prosthetic valve and LA and/or LAA thrombus, suboptimal INR, and AF predict EE, clinical and echocardiographic data support the protective effect of paraprosthetic moderate to severe MR against EE in pts with mitral prosthetic valves. [source] Predictors for Maintenance of Sinus Rhythm after Cardioversion in Patients with Nonvalvular Atrial FibrillationECHOCARDIOGRAPHY, Issue 5 2002Ökçün M.D. Recurrence of atrial fibrillation (AF) after cardioversion (CV) to sinus rhythm (SR) is determined by various clinical and echocardiographic parameters. Transesophageal echocardiographic (TEE) parameters have been the focus of clinicians' interests for restoring and maintaining SR. This study determined the clinical, transthoracic, and TEE parameters that predict maintenance of SR in patients with nonvalvular AF after CV. We enrolled 173 patients with nonvalvular AF in the study. TEE could not be performed in 26 patients prior to CV. Twenty-five patients had spontaneously CV prior to TEE. Six patients were excluded because of left atrial (LA) thrombus assessed by TEE. CV was unsuccessful in 6 patients. The remaining 110 consecutive patients (56 men, 54 women, mean age 69 ± 9 years), who had been successfully cardioverted to SR, were prospectively included in the study. Fifty-seven (52%) patients were still in SR 6 months after CV. Age, gender, the configuration of the fibrillation wave on the electrocardiogram, pulmonary venous diastolic flow, and the presence of diabetes, hypertension, coronary artery disease, mitral annulus calcification, and mitral valve prolapse (MVP) did not predict recurrence. Duration of AF, presence of chronic obstructive pulmonary disease (COPD), LA diameter, left ventricular ejection fraction (EF), left atrial appendage peak flow (LAAPF), LAA ejection fraction (LAAEF), pulmonary venous systolic flow (PVSF), and the presence of LA spontaneous echo contrast (LASEC) predicted recurrence of AF 6 months after CV. In multivariate analysis, LAAEF < 30% was found to be the only independent variable (P < 0.0012) predicting recurrence at 6 months after CV in patients with nonvalvular AF. LAAEF more than 30% had a sensitivity of 75% and a specificity of 88% in predicting maintenance of SR 6 months after CV in patients with nonvalvular AF. In conclusion, TEE variables often used to determine thromboembolic risk also might be used to predict the outcome of CV. [source] Effect of Inotropic Stimulation on Left Atrial Appendage Function in Atrial Myopathy of Chronic Atrial FibrillationECHOCARDIOGRAPHY, Issue 4 2000MASOOR KAMALESH M.D. Atrial fibrillation (AF) leads to remodeling of the left atrium (LA) and left atrial appendage (LAA), resulting in atrial myopathy. Reduced LA and LAA function in chronic AF leads to thrombus formation and spontaneous echo contrast (SEC). The effect of inotropic stimulation on LAA function in patients with chronic AF is unknown. LAA emptying velocity (LAAEV) and maximal LAA area at baseline and after dobutamine were measured by transesophageal echocardiography in 14 subjects in normal sinus rhythm (NSR) and 6 subjects in AF. SEC in the LA was assessed before and after dobutamine. LAAEV increased significantly in both groups. However, the LAAEV at peak dobutamine in patients with AF remained significantly lower than the baseline LAAEV in patients who were in NSR (P= 0.009). Maximal LAA area decreased significantly with dobutamine in both groups, but LAA area at peak dose of dobutamine inpatients with AF remained greater than baseline area in those in NSR (P= 0.01). Despite the increase in LAAEV, SEC improved in only two of five patients. We conclude that during AF, the LAA responds to inotropic stimulation with only a modest improvement in function. [source] Functional response and size-dependent foraging on aquatic and terrestrial prey by brown trout (Salmo trutta L.)ECOLOGY OF FRESHWATER FISH, Issue 2 2010P. Gustafsson Gustafsson P, Bergman E, Greenberg LA. Functional response and size-dependent foraging on aquatic and terrestrial prey by brown trout (Salmo trutta L.).Ecology of Freshwater Fish 2010: 19: 170,177. © 2010 John Wiley & Sons A/S Abstract ,, Terrestrial invertebrate subsidies are believed to be important energy sources for drift-feeding salmonids. Despite this, size-specific use of and efficiency in procuring this resource have not been studied to any great extent. Therefore, we measured the functional responses of three size classes of wild brown trout Salmo trutta (0+, 1+ and ,2+) when fed either benthic- (Gammarus sp.) or surface-drifting prey (Musca domestica) in laboratory experiments. To test for size-specific prey preferences, both benthic and surface prey were presented simultaneously by presenting the fish with a constant density of benthic prey and a variable density of surface prey. The results showed that the functional response of 0+ trout differed significantly from the larger size classes, with 0+ fish having the lowest capture rates. Capture rates did not differ significantly between prey types. In experiments when both prey items were presented simultaneously, capture rate differed significantly between size classes, with larger trout having higher capture rates than smaller trout. However, capture rates within each size class did not change with prey density or prey composition. The two-prey experiments also showed that 1+ trout ate significantly more surface-drifting prey than 0+ trout. In contrast, there was no difference between 0+ and ,2+ trout. Analyses of the vertical position of the fish in the water column corroborated size-specific foraging results: larger trout remained in the upper part of the water column between attacks on surface prey more often than smaller trout, which tended to seek refuge at the bottom between attacks. These size-specific differences in foraging and vertical position suggest that larger trout may be able to use surface-drifting prey to a greater extent than smaller conspecifics. [source] Spatial and temporal evaluation of metal concentrations in soils and sediments from new orleans, louisiana, USA, following hurricanes Katrina and RitaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2007Michael T. Abel Abstract During January 2006, soil and sediment samples from 75 sites in the New Orleans (LA, USA) area were collected and tested for 26 inorganic elements. The study design was intended to provide a spatial pattern of metal concentrations within the city following hurricanes Katrina and Rita. The sampling design included four transects that traversed the city in a north,south direction and three transects that traversed the city in an east,west direction. Contaminant concentrations were determined at multiple sites within each transect and compared to U.S. Environmental Protection Agency soil screening criteria pertaining to human health. Concentrations of Pb and As exceeded the criteria indiscriminately throughout the city. Of the 75 sites, 14 (19%) exceeded the soil screening criteria for Pb, and 73 (97%) exceeded the criteria for As. Forty-three of the 75 sites coincided with a previous sampling event in October 2005. Metal concentrations were evaluated for temporal comparisons using a pair sampled t test. Arsenic concentrations differed significantly over time, but Pb concentrations did not. [source] Effect of conditioning horses with short intervals at high speed on biochemical variables in bloodEQUINE VETERINARY JOURNAL, Issue S36 2006A. LINDNER Summary Reasons for performing study: There is limited published work on the effect of training using intensive and short intervals of exercise to condition horses for racing. Objectives: To examine the effect of conditioning horses 1, 2 or 3 x a week using 2 short fast exercise intervals on blood lactate (LA), plasma ammonia (NH3) and urea (urea) as well as creatine kinase (CK) activity. Methods: Thoroughbreds (age 4,5 years) were conditioned at near maximal speed (12,14 m/sec) over 100 m, on 2 occasions separated by a 10 min period at walk, on dirt track (conditioning exercise; CE) during a 6 week conditioning period (CP). The CE was undertaken either once (5 horses), twice (5 horses) or 3 times a week (4 horses) during a CP. Before, every 2 weeks during and after the CP, blood was drawn during the CE at 0, 2 and 4 min after each run and additionally 6 min after the 2nd run to measure blood LA and determine the maximal LA post exercise (LAmax). Plasma NH3 was measured in the same samples and the maximal NH3 post exercise (NH3max) determined. Additional blood samples were taken from the horses when stabled before the CE, and 12 and 24 h after to measure urea and CK activity in plasma. Results: There was no differential effect of the number of weekly CE on LAmax, NH3max, LA and NH3 immediately after exercise (LAO and NH30). Conditioning did not have an effect on LAmax and LAO after the 1st interval (P>0.05), but LAO after the 2nd interval was lower after conditioning. NH3max after the 1st and 2nd exercise interval decreased in response to the conditioning, but not NH3 immediately after exercise (P>0.05). Median plasma CK activity 12 h after exercise was higher than before exercise and returned to pre-exercise levels 24 h post exercise when horses were exercised once and twice/week. In contrast, the median plasma CK activity of horses exercising 3 times/week remained at the pre-exercise level 12 and 24 h post exercise (P>0.05). Conclusion: Conditioning horses with 2 intervals of 100 m at near maximal speed had a positive effect on blood LA and plasma NH3. Potential relevance: With the type of exercise examined, the fitness of racing horses can be maintained and eventually improved. In further studies the effect of increasing the number of runs in one exercise session should be investigated. [source] The workload of riding-school horses during jumpingEQUINE VETERINARY JOURNAL, Issue S36 2006M. M. SLOET Van OLDRUITENBORGH-OOSTERBAAN Summary Reasons for performing the study: As there are no reports on the real workload of horses that jump fences, this study was undertaken in riding-school horses. Objective: To compare the workload of horses jumping a course of fences with that of horses cantering over the same course at the same average speed without jumping fences. The workload variables included heart rate (HR), packed cell volume (PCV), acid-base balance (venous pH, pCO2, HCO3,) and blood lactate (LA), glucose, total protein and electrolyte concentrations. Methods: Eight healthy riding-school horses performed test A (a course of approximately 700 m with 12 jumps from 0.8-1.0 m high at an average speed of approximately 350 m/min) and test B (same course at the same speed, but without the rails) in a crossover study with at least 4 h between the 2 tests. Before each test the horses were fitted with a heart rate meter (Polar Electro)1. Blood samples were taken from the jugular vein at rest prior to the test, after warm-up before starting the course, immediately after the course and after recovery. All samples were analysed immediately. Results: The mean ± s.d maximal HR (beats/min) during the course (184 ± 17 and 156 ± 21, respectively) and the mean HR after recovery (75 ± 6 and 63 ± 7, respectively) were significantly higher in test A compared to test B (P=0.001 and P=0.007 respectively). The mean LA concentrations after the course and after recovery (mmol/1) were significantly higher in test A (3.6 ± 2.7 and 1.0 ± 0.9, respectively) compared to test B (0.9 ± 0.5 and 0.3 ± 0.1, respectively), (P=0.016 and P = 0.048 respectively). The mean PCV (1/1) after the course and after recovery was also significantly different between tests A (0.48 ± 0.04 and 0.39 ± 0.03, respectively) and B (0.42 ± 0.04 and 0.36 ± 0.03, respectively) (P<0.01). The mean pH and the mean HCO3, (mmol/1) after the course were significantly lower in test A (7.40 ± 0.04 and 28.9 ± 1.4, respectively) compared to test B (7.45 ± 0.03 and 30.4 ± 2.3, respectively) (P<0.05). Conclusions: This study indicates that in riding-school horses jumping fences, even at a low level competition, provokes a significant workload compared to cantering the same distance and speed without fences. Potential relevance: This study makes it clear that the extra workload of jumping fences should be taken into account in the training programmes of jumping horses. Further research with more experienced horses jumping higher fences will reveal the workload for top-level jumping horses. [source] Haematological and respiratory gas changes in horses and mules exercised at altitude (3800 m)EQUINE VETERINARY JOURNAL, Issue S36 2006H. M. GREENE Summary Reason for performing study: Despite the common use of equids as visitors to high altitude mountainous environments, there are a paucity of carefully orchestrated scientific approaches. Further, again as a function of a common perceived advantage of mules over horses in these similar environments there are needs for controlled comparisons between these 2 equids. Objective: To measure haematological and respiratory function in horses and mules at low altitude (225 m), at rest and post exercise. In addition the rate and magnitude of these changes were followed over a 13 day period at high altitude (3800 m) to contrast acclimatisation. Methods: Resting and exercise venous blood samples (1 min post exercise) were obtained from 6 horses and 5 mules housed at 225 m (LA) and then transported to 3800 m (HA) for 13 days. The standardised exercise tests at both LA and HA consisted of trotting (3.0 m/sec) up an incline (6%) for 2 km. Data were analysed with repeated measures ANOVA (comparison of altitude acclimatisation and species) for changes in haematological and respiratory gases. Results: At low altitude, no group differences were found with both resting (P=0.69) and exercising (P=0.74) heart rates. Resting PCV was 8% lower in the mules (P=0.02) and 20% lower during exercise (P=0.02). Horses had significantly higher 2,3-diphosphoglycerate (2,3-DPG)/g Hb at both rest (P=0.003) and exercise (P=0.03). Exercise at HA increased PCV (P=0.03) in both groups, but the increase was attenuated in the mules compared to horses. The increase with 2,3-DPG/g Hb was expressed at HA in both groups (P=0.001) and was also attenuated in mules (P=0.03). Both groups were alkalotic compared to LA (P=0.001), and there were no group differences (P = 0.95). Conclusion: Of the variables measured, the most notable distinction between species was identified for only PCV and 2,3-DPG with both higher in horses, at both LA and HA. While the attenuated response of PCV in mules for the same exercise might argue for an improved adaptation to altitude, the lower 2,3-DPG might not. Other variables during the exercise bout were not different between species. [source] Muscarinic control of graded persistent activity in lateral amygdala neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006Alexei V. Egorov Abstract The cholinergic system is crucially involved in several cognitive processes including attention, learning and memory. Muscarinic actions have profound effects on the intrinsic firing pattern of neurons. In principal neurons of the entorhinal cortex (EC), muscarinic receptors activate an intrinsic cation current that causes multiple self-sustained spiking activity, which represents a potential mechanism for transiently sustaining information about novel items. The amygdala appears to be important for experience-dependent learning by emotional arousal, and cholinergic muscarinic influences are essential for the amygdala-mediated modulation of memory. Here we show that principal neurons from the lateral nucleus of the amygdala (LA) can generate intrinsic graded persistent activity that is similar to EC layer V cells. This firing behavior is linked to muscarinic activation of a calcium-sensitive non-specific cation current and can be mimicked by stimulation of cholinergic afferents that originate from the nucleus basalis of Meynert (n. M). Moreover, we demonstrate that the projections from the n. M. are essential and sufficient for the control and modulation of graded firing activity in LA neurons. We found that activation of these cholinergic afferents (i) is required to maintain and to increase firing rates in a graded manner, and (ii) is sufficient for the graded increases of stable discharge rates even without an associated up-regulation of Ca2+. The induction of persistent activity was blocked by flufenamic acid or 2-APB and remained intact after Ca2+ -store depletion with thapsigargin. The internal ability of LA neurons to generate graded persistent activity could be essential for amygdala-mediated memory operations. [source] Fear learning induces persistent facilitation of amygdala synaptic transmissionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2005Bradley W. Schroeder Abstract In the maintenance phase of fear memory, synaptic transmission is potentiated and the stimulus requirements and signalling mechanisms are altered for long-term potentiation (LTP) in the cortico-lateral amygdala (LA) pathway. These findings link amygdala synaptic plasticity to the coding of fear memories. Behavioural experiments suggest that the amygdala serves to store long-term fear memories. Here we provide electrophysiological evidence showing that synaptic alterations in rats induced by fear conditioning are evident in vitro 10 days after fear conditioning. We show that synaptic transmission was facilitated and that high-frequency stimulation dependent LTP (HFS,LTP) of the cortico-lateral amygdala pathway remained attenuated 10 days following fear conditioning. Additionally, we found that the low-frequency stimulation dependent LTP (LFS,LTP) measured 24 h after fear conditioning was absent 10 days post-training. The persistent facilitation of synaptic transmission and occlusion of HFS,LTP suggests that, unlike hippocampal coding of contextual fear memory, the cortico-lateral amygdala synapse is involved in the storage of long-term fear memories. However, the absence of LFS,LTP 10 days following fear conditioning suggests that amygdala physiology 1 day following fear learning may reflect a dynamic state during memory stabilization that is inactive during the long-term storage of fear memory. Results from these experiments have significant implications regarding the locus of storage for maladaptive fear memories and the synaptic alterations induced by these memories. [source] NMDA receptors are essential for the acquisition, but not expression, of conditional fear and associative spike firing in the lateral amygdalaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2004Ki A. Goosens Abstract We examined the contribution of N -methyl- D -aspartate (NMDA) receptors (NMDARs) to the acquisition and expression of amygdaloid plasticity and Pavlovian fear conditioning using single-unit recording techniques in behaving rats. We demonstrate that NMDARs are essential for the acquisition of both behavioral and neuronal correlates of conditional fear, but play a comparatively limited role in their expression. Administration of the competitive NMDAR antagonist ±-3-(2-carboxypiperazin-4-yl) propyl-1-phosphonic acid (CPP) prior to auditory fear conditioning completely abolished the acquisition of conditional freezing and conditional single-unit activity in the lateral amygdala (LA). In contrast, CPP given prior to extinction testing did not affect the expression of conditional single-unit activity in LA, despite producing deficits in conditional freezing. Administration of CPP also blocked the induction of long-term potentiation in the amygdala. Together, these data suggest that NMDARs are essential for the acquisition of conditioning-related plasticity in the amygdala, and that NMDARs are more critical for regulating synaptic plasticity and learning than routine synaptic transmission in the circuitry supporting fear conditioning. [source] Synaptic and non-synaptic mechanisms of amygdala recruitment into temporolimbic epileptiform activitiesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2003Julia Klueva Abstract Lateral amygdala (LA) activity during synchronized-epileptiform discharges in temporolimbic circuits was investigated in rat horizontal slices containing the amygdala, hippocampus (Hip), perirhinal (Prh) and lateral entorhinal (LEnt) cortex, through multiple-site extra- and intracellular recording techniques and measurement of the extracellular K+ concentration. Application of 4-aminopyridine (50 µm) induced epileptiform discharges in all regions under study. Slow interictal-like burst discharges persisted in the Prh/LEnt/LA after disconnection of the Hip, seemed to originate in the Prh as shown from time delay analyses, and often preceded the onset of ictal-like activity. Disconnection of the amygdala resulted in de-synchronization of epileptiform discharges in the LA from those in the Prh/LEnt. Interictal-like activity was intracellularly reflected in LA projection neurons as ,-aminobutyric acid (GABA)A/B receptor-mediated synaptic responses, and depolarizing electrogenic events (spikelets) residing on the initial phase of the GABA response. Spikelets were considered antidromically conducted ectopic action potentials generated at axon terminals, as they were graded in amplitude, were not abolished through hyperpolarizing membrane responses (which effectively blocked evoked orthodromic action potentials), lacked a clear prepotential or synaptic potential, were not affected through blockers of gap junctions, and were blocked through remote application of tetrodotoxin at putative target areas of LA projection neurons. Remote application of a GABAB receptor antagonist facilitated spikelet generation. A transient elevation in the extracellular K+ level averaging 3 mm above baseline occurred in conjunction with interictal-like activity in all areas under study. We conclude that interictal-like discharges in the LA/LEnt/Prh spread in a predictable manner through the synaptic network with the Prh playing a leading role. The rise in extracellular K+ may provide a depolarizing mechanism for recruitment of interneurons and generation of ectopic action potentials at axon terminals of LA projection neurons. Antidromically conducted ectopic action potentials may provide a spreading mechanism of seizure activity mediated by diffuse axonal projections of LA neurons. [source] Lewis Acid Induced [2+2] Cycloadditions of Silyl Enol Ethers with ,,,-Unsaturated Esters: A DFT AnalysisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2005Manuel Arnó Abstract The Lewis acid (LA) induced cycloaddition of trimethysilyl vinyl ether with methyl acrylate has been studied by DFT methods at the B3LYP/6-31G* level. In the absence of an LA, a [4+2] cycloaddition between the silyl enol ether and methyl acrylate in the s-cis conformation takes place through an asynchronous, concerted bond-formation process. This cycloaddition presents a large activation enthalpy of 21.1 kcal,mol,1. Coordination of the LA AlCl3 to the carbonyl oxygen atom of methyl acrylate yields a change of molecular mechanism from a concerted to a two-step mechanism and produces a drastic reduction of the activation energy. This stepwise mechanism is initialized by the nucleophilic attack of the enol ether at the ,-position of methyl acrylate in a Michael-type addition. The very low activation energy (7.1 kcal,mol,1)associated with this nucleophilic attack can be related to the increase of the electrophilicity of the LA-coordinated ,,,-unsaturated ester, which favors the cycloaddition through a polar process. The subsequent ring-closure allows the formation of the corresponding [2+2] and [4+2] cycloadducts. While the [4+2] cycloadduct is formed by kinetic control, the [2+2] cycloadducts are formed by thermodynamic control. The energetic results provide an explanation for the conversion of [4+2] cycloadducts into the thermodynamically more stable [2+2] ones. The cis/trans ratio found for the catalytic [2+2] process is in agreement with the experimental outcome. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Bilayer localization of membrane-active peptides studied in biomimetic vesicles by visible and fluorescence spectroscopiesFEBS JOURNAL, Issue 22 2003Tanya Sheynis Depth of bilayer penetration and effects on lipid mobility conferred by the membrane-active peptides magainin, melittin, and a hydrophobic helical sequence KKA(LA)7KK (denoted KAL), were investigated by colorimetric and time-resolved fluorescence techniques in biomimetic phospholipid/poly(diacetylene) vesicles. The experiments demonstrated that the extent of bilayer permeation and peptide localization within the membrane was dependent upon the bilayer composition, and that distinct dynamic modifications were induced by each peptide within the head-group environment of the phospholipids. Solvent relaxation, fluorescence correlation spectroscopy and fluorescence quenching analyses, employing probes at different locations within the bilayer, showed that magainin and melittin inserted close to the glycerol residues in bilayers incorporating negatively charged phospholipids, but predominant association at the lipid,water interface occurred in bilayers containing zwitterionic phospholipids. The fluorescence and colorimetric analyses also exposed the different permeation properties and distinct dynamic influence of the peptides: magainin exhibited the most pronounced interfacial attachment onto the vesicles, melittin penetrated more into the bilayers, while the KAL peptide inserted deepest into the hydrophobic core of the lipid assemblies. The solvent relaxation results suggest that decreasing the lipid fluidity might be an important initial factor contributing to the membrane activity of antimicrobial peptides. [source] Stepwise proteolytic removal of the , subdomain in ,-lactalbuminFEBS JOURNAL, Issue 15 2001The protein remains folded, can form the molten globule in acid solution Bovine ,-lactalbumin (,-LA) is an ,/, protein which adopts partly folded states when dissolved at low pH (A-state), by removal of the protein-bound calcium at neutral pH and low salt concentration (apo-state), as well as in aqueous trifluoroethanol. Previous spectroscopic studies have indicated that the A-state of ,-LA at pH 2.0, considered a prototype molten globule, has a native-like fold in which the helical core is mostly retained, while the , subdomain is less structured. Here, we investigate the conformational features of three derivatives of ,-LA characterized by a single peptide bond fission or a deletion of 12 or 19/22 amino-acid residues of the , subdomain of the native protein (approximately from residue 34 to 57). These ,-LA derivatives were obtained by limited proteolysis of the protein in its partly folded state(s). A nicked ,-LA species consisting of fragments 1-,3,40 and 41,123 (nicked-LA) was prepared by thermolytic digestion of the 123-residue chain of ,-LA in 50% (v/v) aqueous trifluoroethanol. Two truncated or gapped protein species given by fragments 1,40 and 53,123 (des,1-LA) or fragments 1,34 and 54-,57,123 (des,2-LA) were obtained by digestion of ,-LA with pepsin in acid or with proteinase K at neutral pH in its apo-state, respectively. The two protein fragments of nicked or gapped ,-LA are covalently linked by the four disulfide bridges of the native protein. CD measurements revealed that, in aqueous solution at neutral pH and in the presence of calcium, the three protein species maintain the helical secondary structure of intact ,-LA, while the tertiary structure is strongly affected by the proteolytic cleavages of the chain. Temperature effects of CD signals in the far- and near-UV region reveal a much more labile tertiary structure in the ,-LA derivatives, while the secondary structure is mostly retained even upon heating. In acid solution at pH 2.0, the three ,-LA variants adopt a conformational state essentially identical to the molten globule displayed by intact ,-LA, as demonstrated by CD measurements. Moreover, they bind strongly the fluorescent dye 8-anilinonaphthalene-1-sulfonate, which is considered a diagnostic feature of the molten globule of proteins. Therefore, the , subdomain can be removed from the ,-LA molecule without impairing the capability of the rest of the chain to adopt a molten globule state. The results of this protein dissection study provide direct experimental evidence that in the ,-LA molten globule only the , domain is structured. [source] Geoarchaeology of the Boca Negra Wash Area, Albuquerque Basin, New Mexico, USAGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2006Vance T. Holliday Dozens of Paleoindian sites, including the Boca Negra Wash (BNW) Folsom site (LA 124474), are scattered across a basalt plateau (the West Mesa) on the western side of the Albuquerque Basin, and adjacent uplands. The BNW site, like many others in the area, is located near a small (,60 × 90 m) playa basin that formed in a depression on the basalt surface and was subsequently covered by an eolian sand sheet (Unit 1) dated by OSL to ,23,000 yr B.P. Most of the basin fill is ,2 m of playa mud (Units 2 and 3) dating ,13,970 14C yr B.P. (17,160,16,140 cal yr B.P.) at the sand,mud interface to ,2810 14C yr B.P. (,2960,2860 cal yr B.P.) at the top. C/N ratios suggest that the BNW playa basin probably held water more often during the Folsom occupation; stable carbon isotope values indicate C3 vegetation was more common as well, but C4 grasses became dominant in the Holocene. Cores extracted from four playa basins nearby revealed a similar stratigraphy and geochronology, documenting presence of wetlands on playa floors during the Paleoindian occupation of the area. © 2006 Wiley Periodicals, Inc. [source] Antimicrobial activity studies of the metal complexes derived from cyclobutane-substituted thiazole carbamate ligandsHETEROATOM CHEMISTRY, Issue 7 2001Alaaddin Çukuroval Two novel monodentate carbamate ligands derived mainly from 4-(1-methyl-1-phenylcyclobutyl-3-yl)-2-aminothiazole and 4-(1-phenyl-1-methylcyclobutane-3-yl)-2-(N -methyl)aminothiazole, have been prepared. The ligands and their metal complexes have been characterized by elemental analyses, IR, 13C, and 1H NMR spectra, as well as UV,Vis, and magnetic susceptibility measurements. Both ligands contain 1 mole of water of crystallization and all complexes are mononuclear. Antimicrobial activities of the ligands and their complexes have been screened against the Bacillus subtitis IMG 22 (bacteria), Micrococcus luteus LA 2971 (bacteria), Escherichia coli DM (bacteria), Staphylococcus aureus COWAN I (bacteria), Saccharamyces cerevisiae UGA 102 (yeast), and Candida albicans CCM 314 (yeast). Thermal properties of the ligands and their complexes have been studied by thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC). © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:665,670, 2001 [source] | |||||||||||||||||||||||||||||||||||||||||||||||||