CONGESTIVE HEART FAILURE, Issue 1 2010
Rhidian J. Shelton MRCP
Congest Heart Fail. 2010;16:3,9. ©2009 Wiley Periodicals, Inc. The prevalence of atrial fibrillation (AF) in patients with heart failure (HF) is high, but longitudinal studies suggest that the incidence of AF is relatively low. The authors investigated this paradox prospectively in an epidemiologically representative population of patients with HF and persistent AF. In all, 891 consecutive patients with HF [mean age, 70±10 years; 70% male; left ventricular ejection fraction, 32%±9%] were enrolled. The prevalence of persistent AF at baseline was 22%. The incidence of persistent AF at 1 year was 26 per 1000 person-years, ranging from 15 in New York Heart Association class I/II to 44 in class III/IV. AF occurred either at the same time or prior to HF in 76% of patients and following HF in 24%. A risk score was developed to predict the occurrence of persistent AF. The annual risk of persistent AF developing was 0.5% (0%,1.3%) for those in the low-risk group compared with 15% (3.4%,26.6%) in the high-risk group. Despite a high prevalence of persistent AF in patients with HF, the incidence of persistent AF is relatively low. This is predominantly due to AF coinciding with or preceding the development of HF. The annual risk of persistent AF developing can be estimated from clinical variables. [source]

Predictive Value of Admission Electrocardiography in Patients With Heart Failure

CONGESTIVE HEART FAILURE, Issue 4 2008
Karolina M. Zareba MD
Admission electrocardiography (ECG) in heart failure (HF) patients provides important diagnostic information; however, there are limited data regarding the prognostic significance of ECG parameters for predicting cardiac events (CEs). The ECGs of 246 patients admitted with acute HF were evaluated for heart rate, rhythm, QRS and ST-T wave abnormalities, QTc duration, QT peak corrected (QTpc), T amplitude, and axis. The end points included rehospitalization for a CE or death during 30-day follow-up. There were 71 (29%) patients with CEs. In patients with CEs, atrial fibrillation (AF) was observed more frequently (27% vs 13%, respectively; P=.009) and QTpc was shorter (370±43 vs 386±44 ms, respectively; P=.020). Multivariate logistic regression analysis revealed that QTpc ,360 ms and AF were predictive of CE after adjustment for clinical covariates. In conclusion, apart from AF, the presence of short QTpc ,360 ms is independently associated with increased risk of rehospitalization or death in HF patients. [source]

Mitral Regurgitation Associated with Mitral Annular Dilation in Patients with Lone Atrial Fibrillation: An Echocardiographic Study

ECHOCARDIOGRAPHY, Issue 8 2009
Takashi Kihara M.D.
Background: Whether and how lone atrial fibrillation (AF) is associated with functional mitral regurgitation (MR) remain unclear. Method: We studied 12 lone AF patients without left ventricular (LV) dysfunction and/or dilatation, who underwent mitral valve annuloplasty for functional mitral regurgitation (MR). Ten lone AF patients without MR served as controls. Results: Lone AF Patients with MR had a greater mitral valve annular area and left atrial area than those without MR. There were no differences in LV volumes or LV ejection fraction. Conclusions: Therefore, we concluded that left atrial dilation and corresponding mitral annular dilation may cause MR in lone AF patients without LV dysfunction and/or dilatation. [source]

Role of Echocardiography in Percutaneous Occlusion of the Left Atrial Appendage

ECHOCARDIOGRAPHY, Issue 4 2007
Mráz M.D.
Percutaneous occlusion of the left atrial appendage (LAA) is a modern alternative for the treatment of patients with atrial fibrillation (AF) and with a high risk of stroke who are not eligible for long-term anticoagulation therapy. Echocardiography plays a significant role in selecting patients, guiding the procedure, and in the postprocedural follow-up. Objectives and methods: To test the role of transesophagoeal echocardiography (TEE) and intracardiac echocardiography (ICE) in facilitating and shortening the procedure. Results: ICE represents a more convenient approach in patients who are not under generally anesthesia and helps to facilitate transseptal puncture. On the other hand, TEE, having the ability to rotate the image plane, helps to better determine the position of the occluder. Conclusions: Echocardiographic guidance of this procedure is essential. Which approach will be preferred will depend on the development of these two methods. [source]

EFFECT OF PARAPROSTHETIC MODERETE TO SEVERE MITRAL REGURGITATION ON EMBOLIC EVENTS IN PATIENTS WITH PROSTHETIC MITRAL VALVES

ECHOCARDIOGRAPHY, Issue 5 2004
C. 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 Fibrillation

ECHOCARDIOGRAPHY, Issue 5 2002
Ökçün 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 Fibrillation

ECHOCARDIOGRAPHY, Issue 4 2000
MASOOR 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]

Electrochemical Preparation of Poly(acriflavine) Film-Modified Electrode and Its Electrolcatalytic Properties Towards NADH, Nitrite and Sulfur Oxoanions

ELECTROANALYSIS, Issue 9 2007
Shen-Ming Chen
Abstract Electrochemical polymerization of acriflavine (AF) was carried out onto glassy carbon electrodes (GCE) from the aqueous buffer solution containing 1.5×10,3,M AF monomer (pH,3.5) which produced a thin electrochemically active film. This is noted as poly(AF) film modified electrodes (PAF/GCE). This modified electrode was shown a stable reversible redox couple centered at +0.22,V in pH,3.5 buffer solutions. PAF/GCE was found to be more stable in acidic solutions and its formal potential was found to be pH dependent with a slope close to ,60,mV/pH. The electrochemical deposition kinetics of poly(AF) onto gold coated quartz crystal was studied by using electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV). PAF/GCE was found be good mediator for electrochemical oxidation of reduced nicotinamide adenine dinucleotide (NADH) in pH,5 buffer solutions. The electrocatalytic oxidation of SO and electrocatalytic reduction of NO, SO and S2O were carried out at PAF/GCE electrode in acidic aqueous solutions. The electrocatalytic oxidation of NADH was also investigated by using amperometric method. [source]

Management of new onset atrial fibrillation in previously well patients less than 60 years of age

EMERGENCY MEDICINE AUSTRALASIA, Issue 1 2005
David McD Taylor
Abstract Objective:, This study reviewed the ED management of new onset atrial fibrillation (AF) in previously well patients aged less than 60 years. Methods:, We undertook a retrospective review of ED patients from 1998 to 2002 inclusive. The main outcome measures were approaches to rate or rhythm control and anticoagulation, the use of echocardiography, the value of diagnostic testing and the frequency of hospital admission. Results:, Fifty-two patients were identified. In general, all patients were haemodynamically stable. One patient had mild cardiac failure and one was clinically thyrotoxic. Serum potassium was measured in 51 (98%) patients, magnesium in 23 (44%) and cardiac enzymes in 30 (58%); results were generally unhelpful. Thyroid function tests were carried out in 40 (77%) patients; results were unremarkable except for the clinically thyrotoxic patient. No patient had echocardiography in the ED; however, 6 patients (12%) were later found to have major cardiac abnormalities. Forty-four (85%) patients received a variety of medications; 37 (71%) received an anti-arrhythmic and 24 (46%) an antithrombotic. Overall, 17 (33%) patients received theoretically effective therapy for conversion to sinus rhythm. Twenty-two (42%) patients were admitted to hospital. Conclusions:, This study reveals variation in the management of acute AF in previously well, haemodynamically stable, young patients. Pathology testing was frequently carried out with a low yield. There were high rates of attempts to cardiovert, use of antithrombotics and of admission to hospital. Although cardioversion attempts appeared to be contrary to existing guidelines, decisions may have been based primarily on patient symptoms. Echocardiography should be considered prior to anti-arrhythmic therapy. [source]

Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation

EQUINE VETERINARY JOURNAL, Issue 4 2007
D. de CLERCQ
Summary Reason for performing study: Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses. Objectives: To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF. Methods: Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by 1.1 mg/kg bwt/h for 47 h. In the second phase, horses received a second loading dose of 3.74 mg AD/kg bwt/h for 1 h followed by 1.31 mg/kg bwt/h for 47 h. Clinical signs were monitored, a surface ECG and an intra-atrial electrogram were recorded. AD treatment was discontinued when conversion or any side effects were observed. Results: Three of the 6 horses cardioverted successfully without side effects. The other 3 horses did not convert and showed adverse effects, including diarrhoea. In the latter, there were no important circulatory problems, but the diarrhoea continued for 10,14 days. The third horse had to be subjected to euthanasia because a concomitant Salmonella infection worsened the clinical signs. Conclusion: The applied treatment protocol based upon pharmacokinetic data achieved clinically relevant concentrations of AD and desethylamiodarone. Potential relevance: Intravenous AD has the potential to be an alternative pharmacological treatment for AF in horses, although AD may lead to adverse drug effects, particularly with cumulative dosing. [source]

Rivaroxaban , an oral, direct Factor Xa inhibitor , lessons from a broad clinical study programme

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2009
Sylvia Haas
Abstract Anticoagulants are recommended for the prevention and treatment of venous thromboembolism (VTE), prevention of stroke in patients with atrial fibrillation (AF) and secondary prevention in patients with acute coronary syndrome (ACS). There is a clinical need for novel anticoagulants offering improvements over current standard of care, such as fixed oral dosing and no need for routine monitoring. Rivaroxaban, an oral, once-daily, direct Factor Xa inhibitor, has recently completed the RECORD phase III programme for the prevention of VTE in patients undergoing total hip or knee replacement (THR or TKR), an indication for which it is approved in Europe and Canada. It is being investigated in large-scale phase III studies for VTE treatment and prevention of stroke in patients with AF, and phase III studies will soon commence for secondary prevention in patients with ACS. Phase I studies demonstrated that no routine anticoagulation monitoring was required, while phase II studies suggested that fixed daily doses had a wide therapeutic window. The four RECORD studies consistently showed that rivaroxaban was significantly more effective than enoxaparin in the prevention of VTE after THR and TKR, with a similar safety profile. This review describes the development of this novel anticoagulant, from bench to bedside. [source]

Alkali Metal (Li+,Cs+) Salts with Hexafluorochromate(V), Hexafluorochromate(IV), Pentafluorochromate(IV), and Undecafluorodichromate(IV) Anions

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2008
Zoran Mazej
Abstract The compounds ACrF6 (A = Li,Cs) were prepared by photochemical reactions of AF/CrF3 mixtures in anhydrous HF with elemental F2 at ambient temperature. The crystal structures of compounds ACrF6 (A = K,Cs) are analogous to that of KOsF6, and NaCrF6 exhibits polymorphism. The trigonal phase (II) can be classified to have the well-known LiSbF6 type of structure, while the crystal structure of the orthorhombic modification (I) appears to be a new structure-type. Thermal decomposition of the ACrF6 salts produce ACrF5(A = Rb, Cs), ACrF5/A2CrF6 (A = K), or A2CrF6 (A = Li, Na). These compounds undergo partial solvolysis in anhydrous HF with precipitation of CrF4. From the remaining solutions of the [CrF6]2, anions and dissolved AF (A = Li,Cs), single crystals of ACrF5 (A = K,Cs), A2CrF6·2HF (A = Na, K), A2CrF6·4HF (A = Rb, Cs), Li2CrF6, and K3Cr2F11·2HF were grown, and their crystal structures determined. The main structural feature of the ACrF5 compounds is the infinite zig-zag [CrF5]nn, chain of distorted [CrF6] octahedra joined by cis vertices. The crystal structures of A2CrF6·2HF (A = Na, K) and A2CrF6·4HF (A = Rb, Cs) consist of distorted [CrF6]2, octahedra involved in moderate to strong hydrogen bonding with HF molecules, while two A+ cations compensate the negative charge of each octahedron. In Na2CrF6·2HF, two neighboring HF molecules are involved in moderate to strong hydrogen bonding with each other. (HF)2 dimers with a parallelogram structure are formed. The mutual interactions in the crystal structure of K2CrF6·2HF differ from those found in Na2CrF6·2HF. In the former, each HF molecule interacts with the [CrF6]2, anion and three K+ cations. A2CrF6·4HF compounds of Rb and Cs are isostructural. Their structures consist of A+ cations and [CrF6]2, anions involved in hydrogen bonding with two sets of HF molecules in the trans position. The crystal structure of K3Cr2F11·2HF reveals a rare case of the [M2F11]3, anion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Modulation by adenosine of both muscarinic M1 -facilitation and M2 -inhibition of [3H]-acetylcholine release from the rat motor nerve terminals

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2002
Laura Oliveira
Abstract The crosstalk between adenosine and muscarinic autoreceptors regulating evoked [3H]-acetylcholine ([3H]-ACh) release was investigated on rat phrenic nerve-hemidiaphragm preparations. Motor nerve terminals possess facilitatory M1 and inhibitory M2 autoreceptors that can be activated by McN-A-343 (1,30 µm) and oxotremorine (0.3,100 µm), respectively. The muscarinic receptor antagonist, dicyclomine (3 nm,10 µm), caused a biphasic (inhibitory/facilitatory) effect, indicating that M1 -facilitation prevails during 5 Hz stimulation trains. Concomitant activation of AF,DX 116-sensitive M2 receptors was partially attenuated, as pretreatment with M1 antagonists, muscarinic toxin 7 (MT-7, 0.1 nm) and pirenzepine (1 nm), significantly enhanced inhibition by oxotremorine. Activation of A2A -adenosine receptors with CGS 21680C (2 nm) (i) potentiated oxotremorine inhibition, and (ii) shifted McN-A-343-induced facilitation into a small inhibitory effect. Conversely, the A1 -receptor agonist, R- N6 -phenylisopropyl adenosine (R-PIA, 100 nm), attenuated the inhibitory effect of oxotremorine, without changing facilitation by McN-A-343. Synergism between A2A and M2 receptors is regulated by a reciprocal interaction with facilitatory M1 receptors, which may be prevented by pirenzepine (1 nm). During 50 Hz-bursts, facilitation (M1) of [3H]-ACh release by McN-A-343 disappeared, while the inhibitory (M2) effect of oxotremorine became predominant. This muscarinic shift results from the interplay with A2A receptors, as it was precluded by the selective A2A receptor antagonist, ZM 241385 (10 nm). In conclusion, when the muscarinic M1 positive feedback loop is fully operative, negative regulation of ACh release is mediated by adenosine A1 receptors. During high frequency bursts, tonic activation of A2A receptors promotes M2 autoinhibition by braking the M1 receptor operated counteraction. [source]

Perirhinal cortex resolves feature ambiguity in complex visual discriminations

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2002
Timothy J. Bussey
Abstract The present experiment tested predictions of a ,perceptual,mnemonic/feature conjunction' (PMFC) model of perirhinal cortex function. The model predicts that lesions of perirhinal cortex should disrupt complex visual discriminations with a high degree of ,feature ambiguity', a property of visual discrimination problems that can emerge when features of an object are rewarded when they are part of one object, but not when part of another. As feature ambiguity is thought to be the critical factor, such effects should be independent of the number of objects to be discriminated. This was tested directly, by assessing performance of control monkeys and monkeys with aspiration lesions of perirhinal cortex on a series of concurrent discriminations in which the number of object pairs was held constant, but the degree of feature ambiguity was varied systematically. Monkeys were tested in three conditions: Maximum Feature Ambiguity, in which all features were explicitly ambiguous (AB+, CD+, BC,, AD,; the biconditional problem); Minimum Feature Ambiguity, in which no features were explicitly ambiguous (AB+, CD+, EF,, GH,); and Intermediate Feature Ambiguity, in which half the features were explicitly ambiguous (AB+, CD+, CE,, AF,). The pattern of results closely matched that predicted by simulations using a connectionist network: monkeys with perirhinal cortex lesions were unimpaired in the Minimum Feature Ambiguity condition, mildly impaired in the Intermediate Feature Ambiguity condition and severely impaired in the Maximum Feature Ambiguity condition. These results confirm the predictions of the PMFC model, and force a reconsideration of prevailing views regarding perirhinal cortex function. [source]

A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescence

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2010
Avijit Banerjee
Banerjee A, Cook R, Kellow S, Shah K, Festy F, Sherriff M, Watson T. A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescence. Eur J Oral Sci 2010; 118: 75,79. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci This study aimed to investigate the null hypothesis that there is no relationship between the microhardness of carious dentine and its native autofluorescence (AF). Six extracted, carious molars were sectioned through natural lesions in the mesio-distal longitudinal plane. The Knoop microhardness (Knoop hardness number, KHN) of the cut surfaces of each sample was recorded at regular intervals through sound and carious dentine. Confocal fibre-optic micro-endoscopic (CFOME) examination of the carious dentine and the sound dentine was carried out at the same intervals using the Cellvizio system (600 ,m wide, flat-end probe) with an excitation wavelength of 488 nm. The blindly collected numerical data were analysed using the original microhardness KHN. The data analysis indicated that the autofluorescence signals increased significantly when the microhardness of dentine dropped below 25 KHN. Therefore, the null hypothesis was disproved, and it was concluded from this investigation that the autofluorescent signal intensity recorded using CFOME could produce an objective and reproducible correlation to the microhardness of carious dentine. Confocal fibre-optic micro-endoscopic examination could have clinical potential as a technology to help delineate the carious dentine that might be excavated in a clinical procedure in vivo. [source]

Which parameters differ in very old patients with chronic atrial fibrillation treated by anticoagulant or aspirin?

FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 5 2008
Antithrombotic treatment of atrial fibrillation in the elderly
Abstract The objective was to determine the main parameters taken into account for the decision of antithrombotic treatment of atrial fibrillation (AF) by vitamin K antagonist or aspirin. This was a prospective clinical study of four clinical services of geriatric medicine. Two hundred and nine inpatients, 84.7 ± 7 years (women 60.8%), with chronic AF were included. The patients were distributed into two groups (anticoagulant or aspirin) according to medical decision. All the decision criteria for treatment were recorded: cardiopathy, conditions of life, clinical examination (nutrition and autonomy, mini-mental state examination (MMSE), walking evaluation, comorbidity), subjective evaluation of risk of falls and glomerular filtration rate. The thromboembolic risk and the bleeding risk, evaluated subjectively for each patient, were compared with two scores of thrombo-embolic risk and bleeding risk. The evolution of the patients was recorded after 3 months. Student's t -test and chi-squared tests were used for statistical analysis. One hundred and two patients (48.8%) received anticoagulant and 107 patients received aspirin. Patients in the aspirin group were significantly older (86.5 ± 6.5 vs. 82.9 ± 7.1 years), with more frequent social isolation, higher systolic blood pressure, and had more important subjective bleeding risk and risk of falls. Patients in the anticoagulant group had significantly more valvulopathies and a more important subjective thromboembolic risk. Thrombo-phlebitis antecedents, dementia, denutrition and walking alterations were only slightly more frequent in patients in the aspirin group. Physicians underestimated thromboembolic risk (one-third of patients) and they overestimated bleeding risk (half of the patients). After 3 months, the two groups did not significantly differ for death, bleeding or ischaemic events. In common practice, the decision of antithrombotic treatment for AF should take into account not only cardiovascular but also geriatric criteria. [source]

Dronedarone: a new option in atrial fibrillation

FUTURE PRESCRIBER, Issue 1 2009
Professor A. John Camm MD
Many antiarrhythmic agents exploiting new mechanisms of action (as well as modified analogues of traditional antiarrhythmic drugs, with different combinations of ion channel- and receptor-blocking effects and less complicated metabolic profiles) are currently being investigated. Dronedarone is an amiodarone derivative that is devoid of iodine atoms and is believed to have a better safety profile than amiodarone. It is the only antiarrhythmic drug for the treatment of atrial fibrillation (AF) that has been shown to improve survival in high-risk patients. This review provides a contemporary insight into the clinical development of dronedarone, its efficacy and safety in preventing recurrent AF, and its potential additional advantage of improving outcome in patients with AF. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Palaeointensity and palaeodirectional studies of early Riphaean dyke complexes in the Lake Ladoga region (Northwestern Russia)

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2008
V. V. Shcherbakova
SUMMARY Results of palaeointensity and palaeomagnetic studies for the volcanic rocks of 1450 Ma, from Early Riphaean Baltic shield dyke complex sampled in Lake Ladoga region (Karelia, Northwestern Russia) are reported. Electron microscope observations, thermomagnetic and hysteresis measurements indicate the presence of single domain (SD) to pseudo-single domain (PSD) titanomagnetite (TM) with low Ti content as the main magnetic mineral. Stepwise alternating field (AF) and/or thermal demagnetization revealed a two-component natural remanent magnetization (NRM) for most of the samples. The characteristic remanent magnetization (ChRM) component was isolated between 440 and 590 °C. Note that the ChRM amounts to 95 per cent of the NRM intensity. The geographic position of the ChRM palaeopoles does not contradict the ,key poles' of the [1270; 1580] Myr time interval, testifying anticlockwise rotation of whole East Europe Craton between 1450 and 1500 Ma. Palaeointensity determinations were performed by Coe-modified Thellier procedure. 35 samples passed our palaeointensity selection criteria and show large linear segments on Arai-Nagata plots. The site mean virtual dipole moment (VDM) varies from 2.00 to 3.91 (× 1022 A m2). Based on these and other observations, we suggest that the Palaeo- and MezoProterozoic was dominated by low VDMs. [source]

REVIEW ARTICLE: An improved manufacturing process for Xyntha/ReFacto AF

HAEMOPHILIA, Issue 5 2010
B. KELLEY
Summary., ReFacto® Antihemophilic Factor is a second-generation antihaemophilia A product manufactured using a process that includes therapeutic grade human serum albumin (HSA) in the cell culture medium, but is formulated without HSA as a stabilizer. Even though this second-generation antihaemophilia product has a good safety profile, a programme was implemented to eliminate all animal- and human-derived raw materials from the production process, thus producing a third-generation product. To that end, HSA has been removed from the master and working cell banks and from the culture medium. The hybridoma-derived monoclonal antibody formerly used in the purification process has been replaced by a chemically synthesized affinity peptide, and a virus-retaining filtration step has been added to enhance the clearance of large viruses, such as retroviruses. The purification process has been validated for the removal of a panel of model viruses and provides significant clearance of all viruses tested. Host cell- and process-derived impurity removal validations also were conducted, including host cell DNA and protein, in addition to the affinity peptide. Compared with the product manufactured according to the original process, these changes had no detectable effect on the structural integrity, stability or clinical efficacy of this antihaemophilia A product. The product produced by the improved manufacturing process is named XynthaÔ/ReFacto AF. [source]

Increase of granzyme B-positive cells in ascitic fluid of patients with spontaneous bacterial peritonitis

HEPATOLOGY RESEARCH, Issue 4 2008
Alessandro Perrella
Spontaneous bacterial peritonitis (SBP) occurs as a direct consequence of bacteria entering ascitic fluid (AF) from the intestinal lumen trough in several ways, including the hematogenous and mesenteric lymph nodes route. There are few studies on the cytokine profile of ascitic-derived mononuclear cells of patients with SBP, particularly on granzyme B (GZB). The aim of the present study was to verify whether patients with SBP have GZB-positive cells, whether they are increased in patients with aseptic ascites, and their trend after antibiotic treatment. We enrolled 36 consecutive patients (24 males and 12 females) with SBP on histologically-proven hepatitis C virus cirrhosis (group A) and 20 patients (11 males and nine females with ascites, but without evidences of SBP (group B). The diagnosis of SBP was made according to the following criteria: positive colture in AF or blood (at least two cultures) and neutrophils in AF (>250 mL polymorphonuclear leukocytes). For these patients we used ELISpot to assay GZB production on purified mononuclear cells in ascitesand peripheral blood, coupled with tumor necrosis factor-, tested using ELISA. A non-parametric statistical analysis was used to assess significant differences and correlations. We found positive culture in all of the patients with SBP (80% Escherichia coli; 20% Enterococcus faecium). Furthermore, the patients in group A had a higher number of GZB spot-forming colonies than the patients in group B (P < 0.001). GZB-positive cells were lower in the peripheral blood than those found in the AF of patients with SBP, while no differences were found between blood and AF in group B. Furthermore, after antibiotic treatment, GZB was reduced in the patients with SBP (P < 0.05). In conclusion, GZB may be an important mediator of the immune response towards bacteria in AF and could be used as a diagnostic tool. [source]

Could exercise be a new strategy to revert some patients with atrial fibrillation?

INTERNAL MEDICINE JOURNAL, Issue 1 2010
P. Gates
Abstract Background: This study is the result of the anecdotal observation that a number of patients with atrial fibrillation (AF) had noted reversion to sinus rhythm (SR) with exercise. We aimed to evaluate the potential role of exercise stress test (EST) for the reversion of AF. Methods: Patients with AF who were scheduled to undergo electrical cardioversion (DCR) underwent EST using a modified Bruce protocol. Results: Eighteen patients (16 male); aged 36,74 years (mean 58 years) were studied. Five patients (27.7%) had successful reversion with exercise (group 1). Thirteen patients remained in AF (group 2). No patient who failed to revert with exercise did so spontaneously before DCR 3 h to 7 months later (median 20 days). Comparison between group 1 and group 2 did not reveal any significant difference Conclusion: This small preliminary study suggests that in some patients it may be possible to revert AF to SR with exercise and avoid DCR and concomitant general anaesthesia. The authors suggest that a larger multicentre randomized trial is warranted to confirm or refute these initial results and if correct identify those who might benefit. [source]

Management of atrial fibrillation in the emergency department

INTERNAL MEDICINE JOURNAL, Issue 4 2003
I. Crozier
Abstract Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is a frequent cause for presentation to the emergency department. With an understanding of the pathophysiology and types of AF, efficient and effective management strategies for AF can be formulated. Patients with paroxysmal AF will often revert spontaneously and can initially be managed on an outpatient basis, unless an antiarrhythmic is commenced. In patients with AF and severe underlying heart disease, the management is primarily directed at the underlying heart disease, supplemented with rate-controlling measures, and prevention of thromboembolic complications. In patients with persistent AF good rate control, early cardioversion and initiation of an antiarrhythmic are likely to reduce the risk of recurrence. (Intern Med J 2003; 33: 182,185) [source]

First time and repeat cardioversion of atrial tachyarrhythmias , a comparison of outcomes

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 8 2010
A. Arya
Summary Introduction:, Repeat cardioversion may be necessary in over 50% of patients with persistent atrial fibrillation (AF), but identifying responders remains challenging. This study evaluates the long-term success of direct current cardioversion (DCCV) and the clinical and echocardiographical parameters that influence them, in over 1000 sedation-cardioversion procedures undertaken at Eastbourne General Hospital between 1996 and 2006. Methods:, A total of 770 patients of mean age (SD) 70.1(10.1) underwent 1013 DCCVs (first n = 665, repeat n = 348) for atrial tachyarrhythmias from 1996 to 2006. Time to persistent arrhythmia recurrence was compared between first and multiple DCCV, and the effect of age, gender, presence of heart disease, left atrial size, fractional shortening, arrhythmia duration, anti-arrhythmic drug therapy (AAD) and other concomitant cardiac medication was evaluated using the Kaplan,Meier method and Cox's Proportional-hazards model. Results:, In all, 33% of first and 29% of repeat DCCVs were in sinus rhythm (SR) at 12 months (m). There was no difference in median time to arrhythmia recurrence (SE) between first and multiple procedures: 1.5 ± 0.1 m (1.3,1.7) and 1.5 ± 0.0 m (1.4,1.6) respectively, p = 0.45. AAD use was significantly higher, arrhythmia duration shorter and more diabetic patients underwent repeat procedures. Amiodarone, OR 0.56, p = 0.04, sotalol, OR 0.61, p = 0.02 and arrhythmia duration, < 6 m, OR 0.72, p = 0.03 were independent predictors of improved outcome in first procedures only. In patients undergoing first procedures on amiodarone or sotalol, median time to arrhythmia recurrence was longer and 12 m SR rates higher, 6.0 ± 2.4 m (42%) than those who had a repeat procedure on the same medication, 1.5 ± 0.1 m (33%), p = 0.06. Conclusions:, The efficacy of first and subsequent DCCV procedures is similar, achieving a similar proportion of SR maintenance at 1 year. However, the benefits of AAD therapy are the greatest following first time procedures. Concomitant AAD therapy should be considered for all first time procedures for persistent AF. [source]

The effect of pretreatment with renin-angiotensin-aldosterone system blockers on cardioversion success and acute recurrence of atrial fibrillation

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2009
A. Dogan
Summary Background:, Renin-angiotensin-aldosterone system (RAS) may be activated during atrial fibrillation (AF). It is unclear whether RAS inhibition may facilitate cardioversion from AF and may prevent acute recurrence of AF (ARAF). We thus investigated the effect of pretreatment with RAS blockers on cardioversion success and ARAF in patients with AF scheduled for elective cardioversion. Methods:, This observational study included 356 patients with AF undergoing elective pharmacological or electrical cardioversion. Of these patients, 135 were not included based on exclusion criteria and the remaining 221 patients were divided into RAS group (n = 116, 69 male) or non-RAS group (n = 105, 58 male) based on precardioversion use of any RAS blocker. Results:, Hypertension, coronary heart disease and heart failure were more frequent in the RAS group. Cardioversion from AF was more successful in the RAS group than in the non-RAS group (%92 vs. %82, p = 0.026). The rate of ARAF was lower in RAS group compared with that in non-RAS group (17% vs. 31%, p = 0.026). In multivariate analysis, pretreatment with RAS blockers in addition to shock number and enlarged left atrium, independently predicted ARAF (OR: 0.33, 95% CI: 0.15,0.75, p = 0.008). Independent predictors of cardioversion success were shock number and left atrial dilatation, but not use of RAS blocker. Conclusion:, Precardioversion use of RAS blockers may reduce ARAF following successful cardioversion of AF, but did not improve electrical cardioversion. [source]

Performance analysis of relative service using TCP-aware marking and dynamic WRED

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2009
Christos Bouras
Abstract The implementation of successful assured forwarding (AF) services according to the DiffServ framework remains a challenging problem today, despite the numerous proposals for assured forwarding per-hop-behaviour (AF PHB) mechanisms and AF-based service implementations. The interaction of the TCP and UDP traffic under an AF-based service and a number of relative issues such as fairness among flows, achievable bandwidth guarantees and qualitative performance have been taken into consideration in this work in order to address the existing limitations. We propose two modules, the TCP-window aware marker (TWAM) and the dynamic WRED (WRED) mechanism for implementing the differentiated services (DiffServ) AF PHB. We provide analytical models and an experimental evaluation in order to demonstrate how they succeed in enhancing the quality, improving the performance and easing the deployment of a production level AF-based service. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Pretibial epidermolysis bullosa: is this case a new subtype with loss of types IV and VII collagen?

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2009
Hong-sun Lee MD
Pretibial epidermolysis bullosa (PEB) is an extremely rare subtype of dominant dystrophic epidermolysis bullosa (DDEB), in which recurrent blistering with scarring predominantly involves the pretibial skin. Nail dystrophy, albopapuloid lesions, and hypertrophic scars may also occur. In PEB, immunohistochemical and electron microscopic studies demonstrate the complete or partial loss of the anchoring fibril (AF) in the basement membrane zone, suggesting disturbed synthesis or excessive degradation of collagen VII, the main component of AF. Interestingly, we report a case of PEB with unusual results of joint loss of types IV and VII collagen. [source]

Molecular analysis of Oenococcus oeni population dynamics and the effect of aeration and temperature during alcoholic fermentation on malolactic fermentation

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2005
Cristina Reguant
Summary The effects of aeration and temperature during alcoholic fermentation (AF) on spontaneous and inoculated malolactic fermentation (MLF) of wine have been analysed by following the population dynamics of Oenococcus oeni strains with multiplex random amplified polymorphic DNA-polymerase chain reaction. It has enabled us to follow precisely the proportion of different autochthonous strains and the starter strain through fermentations. Lack of aeration led to delays in AF, which meant that autochthonous lactic acid bacteria could develop earlier and prevented the starter strain from developing correctly. Temperature was not found to lead to any differences. Two strains were isolated in the same spontaneous MLF, suggesting that, in some cases, multiple strains might be responsible for the degradation of malic acid in wine. It can be concluded that delays in the AF can negatively affect the control of MLF and that this can be studied by following the development of the different strains of O. oeni. [source]

Disc structure function and its potential for repair

INTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 1 2002
J. Melrose
The intervertebral disc (IVD) is the largest predominantly avascular, aneural, alymphatic structure of the human body. It provides articulation between adjoining vertebral bodies and also acts as a weight-bearing cushion dissipating axially applied spinal loads. The IVD is composed of an outer collagen-rich annulus fibrosus (AF) and a central proteoglycan (PG)-rich nucleus pulposus (NP). Superior and inferior cartilaginous endplates (CEPs), thin layers of hyaline-like cartilage, cover the ends of the vertebral bodies. The AF is composed of concentric layers (lamellae) which contain variable proportions of type I and II collagen, this tissue has high tensile strength. The NP in contrast is a gelatinous PG-rich tissue which provides weight-bearing properties to the composite disc structure. With the onset of age, cells in the NP progressively die as this tissue becomes depleted of PGs, less hydrated and more fibrous as the disc undergoes an age-dependent fibrocartilaginous transformation. Such age-dependent cellular and matrix changes can decrease the discs' biomechanical competence and trauma can further lead to failure of structural components of the disc. Annular defects are fairly common and include vertebral rim-lesions, concentric (circumferential) annular tears (separation of adjacent annular lamellae) and radial annular tears (clefts which initiate within the NP). While vascular in-growth around annular tears has been noted, evidence from human post-mortem studies indicate they have a limited ability to undergo repair. Several experimental approaches are currently under evaluation for their ability to promote the repair of such annular lesions. These include growth of AF fibrochondrocytes on a resorbable polycaprolactone (PCL) bio-membrane.1 Sheets of fibrochondrocytes lay down type-I collagen and actin stress fibres on PCL. These matrix components are important for the spatial assembly of the collagenous lamella during annular development and correct phenotypic expression of cells in biomatrices.1 An alternative approach employs preparation of tissue engineered IVDs where AF and NP cells are separately cultured in polyglycolic acid and sodium alginate biomatrices, either separately or within a manifold designed to reproduce the required IVD dimensions for its use as a prospective implant device.2 AF and NP cells have also been grown on tissue culture inserts after their recovery from alginate bead culture to form plugs of tissue engineered cartilage.3 A key component in this latter strategy was the stimulation of the high density disc cell cultures with osteogenic protein-1 (OP-1) 200 ng/mL.3 This resulted in the production of tissue engineered AF and NP plugs with compositions, histochemical characteristics and biomechanical properties approaching those of the native disc tissues.2,3 Such materials hold reat promise in future applications as disc or annular implants. The introduction of appropriate genes into disc cells by gene transduction methodology using adenoviral vectors or ,gene-gun' delivery systems also holds considerable promise for the promotion of disc repair processes.4 Such an approach with the OP-1 gene is particularly appealing.5 The anchoring of discal implants to vertebral bodies has also been evaluated by several approaches. A 3D fabric based polyethylene biocomposite holds much promise as one such anchorage device6 while biological glues used to seal fibrocartilaginous structures such as the AF and meniscus8 following surgical intervention, also hold promise in this area. Several very promising new experimental approaches and strategies are therefore currently under evaluation for the improvement of discal repair. The aforementioned IVD defects are a common cause of disc failure and sites of increased nerve in-growth in symptomatic IVDs in man and are thus often sources of sciatic-type pain. Annular defects such as those described above have formerly been considered incapable of undergoing spontaneous repair thus a clear need exists for interventions which might improve on their repair. Based on the rapid rate of progress and the examples outlined above one may optimistically suggest that a successful remedy to this troublesome clinical entity will be developed in the not so distant future. References 1JohnsonWEBet al. (2001) Directed cytoskeletal orientation and intervertebral disc cell growth: towards the development of annular repair techniques. Trans Orthop Res Soc26, 894. 2MizunoHet al. (2001) Tissue engineering of a composite intervertebral disc. Trans Orthop Res Soc26, 78. 3MatsumotoTet al. (2001) Formation of transplantable disc shaped tissues by nucleus pulposus and annulus fibrosus cells: biochemical and biomechanical properties. Trans Orthop Res Soc26, 897. 4NishidaKet al. (2000) Potential applications of gene therapy to the treatment of intervertebral disc disorders. Clin Orthop Rel Res379 (Suppl), S234,S241. 5MatsumotoTet al. (2001) Transfer of osteogenic protein-1 gene by gene gun system promotes matrix synthesis in bovine intervertebral disc and articular cartilage cells. Trans Orthop Res Soc26, 30. 6ShikinamiY , Kawarada (1998) Potential application of a triaxial three-dimensional fabric (3-DF) as an implant. Biomaterials19, 617,35. [source]

The effects of sex, self gender type, and partner's gender type on interpersonal adjustment during a first encounter: androgynous and stereotypically sex-typed couples

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 2 2000
Kumi Hirokawa
The present study compared the effects of sex, self gender type, and partner's gender type on interpersonal adjustment during a 5-min first encounter of androgynous and stereotypically sex-typed couples. The 52 subjects were assigned to one of four mixed-sex couple types: sex-typed male and female (MF); sex-typed male and androgynous female (MA); androgynous male and sex-typed female (AF); and androgynous male and female (AA). Questionnaires (the State-Trait Anxiety Inventory, and Iceberg Profile) and subjects' behaviors during the interaction were assessed. These data were analyzed by sex, self gender type and partner's gender type using a 2 × 2 ×2 analysis of variance. Our hypothesis that androgynous individuals may have better interpersonal relationships was supported by some of our findings. Androgynous individuals may have better interpersonal adjustment. [source]

A comparative analysis of the differential spatial and temporal distributions of the large (aggrecan, versican) and small (decorin, biglycan, fibromodulin) proteoglycans of the intervertebral disc

JOURNAL OF ANATOMY, Issue 1 2001
JAMES MELROSE
This study provides a comparative analysis of the temporal and spatial distribution of 5 intervertebral disc (IVD) proteoglycans (PGs) in sheep. The main PGs in the 2 and 10 y old sheep groups were polydisperse chondroitin sulphate and keratan sulphate substituted species. Their proportions did not differ markedly either with spinal level or disc zone. In contrast, the fetal discs contained 2 slow migrating (by composite agarose polyacrylamide gel electrophoresis, CAPAGE), relatively monodisperse chondroitin sulphate-rich aggrecan species which were also identified by monoclonal antibody 7-D-4 to an atypical chondroitin sulphate isomer presentation previously found in chick limb bud, and shark cartilage. The main small PG detectable in the fetal discs was biglycan, whereas decorin predominated in the 2 and 10 y old IVD samples; its levels were highest in the outer annulus fibrosus (AF). Versican was most abundant in the AF of the fetal sheep group; it was significantly less abundant in the 2 and 10 y old groups. Furthermore, versican was immunolocalised between adjacent layers of annular lamellae suggesting that it may have some role in the provision of the viscoelastic properties to this tissue. Versican was also diffusely distributed throughout the nucleus pulposus of fetal IVDs, and its levels were significantly lower in adult IVD specimens. This is the first study to identify versican in ovine IVD tissue sections and confirmed an earlier study which demonstrated that ovine IVD cells synthesised versican in culture (Melrose et al. 2000). The variable distribution of the PGs identified in this study provides further evidence of differences in phenotypic expression of IVD cell populations during growth and development and further demonstrates the complexity of the PGs in this heterogeneous but intricately organised connective tissue. [source]