bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental silicification of the extremophilic Archaea Pyrococcus abyssi and Methanocaldococcus jannaschii: applications in the search for evidence of life in early Earth and extraterrestrial rocks
Authors: ORANGE F. , WESTALL F. , DISNAR J.‐R. , PRIEUR D. , BIENVENU N. , LE ROMANCER M. , DÉFARGE CH. 
Published: July 2009

AbstractHydrothermal activity was common on the early Earth and associated micro‐organisms would most likely have included thermophilic to hyperthermophilic species. 3.5–3.3 billion‐year‐old, hydrothermally influenced rocks contain silicified microbial mats and colonies that must have been bathed in warm to hot hydrothermal emanations. Could they represent thermophilic or hyperthermophilic micro‐organisms and if so, how were they preserved? We present the results of an experiment to silicify anaerobic, hyperthermophilic micro‐organisms from the Archaea Domain Pyrococcus abyssi and Methanocaldococcus jannaschii, that could have lived on the early Earth. The micro‐organisms were placed in a silica‐saturated medium for periods up to 1 year. Pyrococcus abyssi cells were fossilized but the M. jannaschii cells lysed naturally after the exponential growth phase, apart from a few cells and cell remains, and were not silicified although their extracellular polymeric substances were. In this first simulated fossilization of archaeal strains, our results suggest that differences between species have a strong influence on the potential for different micro‐organisms to be preserved by fossilization and that those found in the fossil record represent probably only a part of the original diversity. Our results have important consequences for biosignatures in hydrothermal or hydrothermally influenced deposits on Earth, as well as on early Mars, as environmental conditions were similar on the young terrestrial planets and traces of early Martian life may have been similarly preserved as silicified microfossils.
Early worsening heart failure in patients admitted with acute heart failure – a new outcome measure associated with long‐term prognosis?
Authors: Weatherley Beth Davison , Milo‐Cotter Olga , Michael Felker G. , Uriel Nir , Kaluski Edo , Vered Zvi , O’Connor Christopher M. , Adams Kirkwood F. , Cotter Gad 
Published: July 2009

AbstractA major limitation in acute heart failure (AHF) research has been the lack of an outcome measure paralleling re‐infarction in acute coronary syndromes. The aim of the present study was to assess the time course, prognostic factors and outcome of early worsening heart failure (WHF) in patients admitted for AHF to a community hospital. All AHF admissions between December 2003 and March 2004 in a regional medical center were recorded. Patients were followed through admission and for 6 months after discharge. Early WHF was defined as WHF occurring during the initial 7 days from admission. Study endpoints were cardiovascular mortality and WHF (defined as worsening or persistent signs or symptoms of AHF requiring rescue therapy or hospital readmission). Early WHF rate was 29% and was associated with markers of AHF severity on presentation (higher troponin I, lower oxygen saturation, need for mechanical ventilation, intravascular diuretics and inotropes). Early WHF was a powerful predictor of death during 6 months of follow up, with an age‐adjusted hazard ratio of 3.3 (95% confidence interval 1.7–6.3). Early WHF is a common adverse event in patients admitted with AHF, and is associated with AHF severity and excessive 6‐month mortality. WHF should be considered as a clinically important endpoint in AHF studies.
Cyclosporine and sirolimus pharmacokinetics and drug‐to‐drug interactions in kidney transplant recipients
Authors: Felipe Claudia R. , Park Sung‐In , Pinheiro‐Machado Paula G. , Garcia Riberto , Casarini Dulce E. , Moreira Silvia , Tedesco‐Silva Jr Helio , Medina‐Pestana Jose O. 
Published: July 2009

AbstractThis study was conducted to evaluate the pharmacokinetics (pk) and drug interactions between cyclosporine (CsA) and sirolimus (SRL) in kidney transplant recipients. The morning (a.m.) and evening (p.m.) pk of CsA (4–5 mg/kg/dose) and SRL (2 mg,n = 20; 5 mg,n = 33) were evaluated on day 7 (n = 53). CsA showed circadian variation when comparing a.m. and p.m. administration [AUC: 8066 vs. 6699,P < 0.001 (CI 970.9; 1763.6); C0: 272 vs. 245,P = 0.007 (CI 7.5; 46.1)]. SRL showed dose‐proportional pk. Significant and drug‐to‐drug concentration‐dependent pk interactions were observed within a narrow concentration range for both drugs. A fivefold increase in SRL AUC (from a mean of 130 to 538 ng h/mL) was associated with a 25% increase in mean a.m. CsA AUC [7021 to 8811 ng h/mL,P = 0.037, CI (−3461.2; −118.9)] and with a 42% increase in mean p.m. CsA AUC [5386–7639,P = 0.024, CI (−4164.4; −340.7)]. A twofold increase in a.m. CsA AUC (from 5860 to 10 974 ng h/mL) was associated with a 70% increase in mean SRL AUC [223 to 380 ng h/mL,P = 0.0026, CI (−291.7; −22.8)]. A twofold increase in p.m. CsA AUC (from 4573 to 9692 ng h/mL) was associated with a 63% increase in mean SRL AUC [246 to 400 ng h/mL,P = 0.032, CI (−290.7; −16.6)]. CSA shows circadian pk regardless of sirolimus dose or blood concentration. Significant drug‐to‐drug interactions occur within narrow blood drug concentrations. The magnitude of the effect of CsA on SRL blood concentration is higher than that of SRL on CsA blood concentrations. These findings emphasize the need for therapeutic drug monitoring using this drug combination.
Histamine: metabolism, physiology, and pathophysiology with applications in veterinary medicine
Authors: Peters Lisa J. , Kovacic Jan P. 
Published: July 2009

AbstractObjective –To review the human and veterinary literature on histamine physiology and pathophysiology and potential applications for clinical use in veterinary critical care.Data Sources –Human and veterinary clinical studies, reviews, texts, and recent research in histamine receptor and antagonist therapy.Human Data Synthesis –Recent progress in molecular biology has led to a more complete understanding of the enzymes involved in histamine metabolism and histamine receptor physiology. The past decade of research has confirmed the role of histamine in theclassical functions(contraction of smooth muscle, increase in vascular permeability, and stimulation of gastric acid secretion) and has also elucidated newer ones that are now under investigation. Data on the roles of histamine in angiogenesis, circadian rhythm, bone marrow regeneration, bacterial eradication, and cancer are emerging in the literature. Newer histamine antagonists are currently in drug trials and are expected to advance the clinical field in treatment of allergic, gastrointestinal, and cognitive disorders.Veterinary Data Synthesis –Veterinary histamine research is directed at identifying the effects of certain pharmacological agents on blood histamine concentrations and establishing the relevance in clinical disease states. Research demonstrates important species differences in regards to histamine receptor physiology and tissue response. Studies in the area of trauma, sepsis, anaphylaxis, allergy, and gastrointestinal disorders have direct applications to clinical veterinary medicine.Conclusions –Histamine plays a key role in the morbidity and mortality associated with allergy, asthma, gastric ulcers, anaphylaxis, sepsis, hemorrhagic shock, anesthesia, surgery, cardiovascular disease, cancer, CNS disorders, and immune‐mediated disease. Histamine antagonism has been in common use to block its adverse effects. With recent advances in the understanding of histamine receptor physiology, pharmaceutical agents targeting these receptors have increased the therapeutic options.
Comparison of Cryoballoon and Radiofrequency Ablation of Pulmonary Veins in 40 Patients with Paroxysmal Atrial Fibrillation: A Case‐Control Study
Authors: LINHART MARKUS , BELLMANN BARBARA , MITTMANN‐BRAUN ERICA , SCHRICKEL JAN W. , BITZEN ALEXANDER , ANDRIÉ RENÉ , YANG ALEXANDER , NICKENIG GEORG , LICKFETT LARS , LEWALTER THORSTEN 
Published: July 2009

Introduction: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug‐refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved. Methods and Results: In a case‐control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously. Conclusion: PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure‐ and fluoroscopy duration are not longer than in conventional RF ablation.
Catheter Ablation of Recurrent Scar‐Related Ventricular Tachycardia Using Electroanatomical Mapping and Irrigated Ablation Technology: Results of the Prospective Multicenter Euro‐VT‐Study
Authors: TANNER HILDEGARD , HINDRICKS GERHARD , VOLKMER MARIUS , FURNISS STEVE , KÜHLKAMP VOLKER , LACROIX DOMINIQUE , DE CHILLOU CHRISTIAN , ALMENDRAL JESÚS , CAPONI DOMENICO , KUCK KARL‐HEINZ , KOTTKAMP HANS 
Published: July 2009

Catheter Ablation of Ventricular Tachycardia. Introduction: Ventricular tachycardia (VT) late after myocardial infarction is an important contributor to morbidity and mortality. This prospective multicenter study assessed the efficacy and safety of electroanatomical mapping in combination with open‐saline irrigated ablation technology for ablation of chronic recurrent mappable and unmappable VT in remote myocardial infarction. Methods and Results: In 8 European institutions, 63 patients (89% males) were enrolled in the study. All patients had remote myocardial infarction and presented with a median number of 17 (range 1–380) VTs in the preceding 6 months. Incessant VT was present in 14 patients (22%). Left ventricular ejection fraction measured 30 ± 13%. A mean of 3 VTs were targeted per patient and 22% of all patients had only unmappable VT. The mean follow‐up period was 12 ± 3 months. A total of 164 VTs were targeted during catheter ablation. Ablation was acutely successful in 51 patients (81%). One patient (1.5%) experienced a major complication with degeneration of VT into ventricular fibrillation necessitating cardiopulmonary resuscitation maneuvers. However, no death occurred acutely or within the first 30 days after catheter ablation. During the follow‐up, 19 of the initially successful ablated patients (37%) and 31 of all ablated patients (49%) developed some type of VT recurrence. Conclusions: The results of this multicenter study demonstrate the high acute success rate and a low complication rate of irrigated tip catheter ablation of all clinical relevant VTs in remote myocardial infarction. However, during the follow‐up a relevant number of recurrences occurred. (J Cardiovasc Electrophysiol, Vol. 21, pp. 47–53, January 2010)
Radiofrequency Ablation Guided by Mechanical Termination of Idiopathic Ventricular Arrhythmias Originating in the Right Ventricular Outflow Tract
Authors: KÜHNE MICHAEL , SARRAZIN JEAN‐FRANCOIS , CRAWFORD THOMAS , EBINGER MATTHEW , GOOD ERIC , CHUGH AMAN , JONGNARANGSIN KRIT , PELOSI Jr. FRANK , ORAL HAKAN , MORADY FRED , BOGUN FRANK M. 
Published: July 2009

Mapping of Idiopathic Ventricular Arrhythmias. Background: Termination of ventricular tachycardia (VT) by mechanical pressure has been described for fascicular and postinfarction VT. Mechanical interruption of idiopathic ventricular arrhythmias (VT/premature ventricular complexes [PVCs]) arising in the right ventricular outflow tract (RVOT) has not been described in systematic fashion. Methods: Eighteen consecutive patients (13 females, age 49 ± 13 years, ejection fraction 0.55 ± 0.12) underwent mapping and ablation of RVOT VT or PVCs. In 7 patients, 9 distinct VTs (mean cycle length 440 ± 127 ms), and in 11 patients, 11 distinct PVCs originating in the RVOT were targeted. Mechanical termination was considered present if a reproducibly inducible VT was no longer inducible or if frequent PVCs suddenly ceased with the mapping catheter at a particular location. Endocardial activation time, electrogram characteristics, and pace‐mapping morphology were assessed at this location. Radiofrequency energy was delivered if mechanical termination was observed. Results: All targeted arrhythmias were successfully ablated. In 7 of 18 patients (39%), catheter manipulation terminated the arrhythmia with the mapping catheter located at a particular site. Local endocardial activation time was earlier at sites of mechanical termination (−31 ± 7 ms) compared with effective sites without termination (−25 ± 3 ms, P = 0.04). The 10‐ms isochronal area was smaller in patients with mechanical interruption (0.35 ± 0.2 cm2) than in patients without mechanical termination (1.33 ± 0.9 cm2, P = 0.01). At all sites susceptible to mechanical trauma, the pace map displayed a match with the targeted VT/PVC. All sites where mechanical termination of VT or PVCs occurred were effective ablation sites. Conclusions: Mechanical suppression at the site of origin of idiopathic RVOT arrhythmias frequently occurs during the mapping procedure and is a reliable indicator of effective ablation sites. Mechanical termination of RVOT arrhythmias may be indicative of a more localized arrhythmogenic substrate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 42–46, January 2010)
The Optimal Automatic Algorithm for the Mapping of Complex Fractionated Atrial Electrograms in Patients With Atrial Fibrillation
Authors: TSAI WEN‐CHIN , LIN YENN‐JIANG , TSAO HSUAN‐MING , CHANG SHIH‐LIN , LO LI‐WEI , HU YU‐FENG , CHANG CHIEN‐JUNG , TANG WEI‐HUA , TUAN TA‐CHUN , UDYAVAR AMEYA R. , WANG JI‐HUNG , CHEN SHIH‐ANN 
Published: July 2009

CFAEs and the Voltage. Introduction: Catheter ablation of atrial fibrillation (AF) can be guided by the identification of complex fractionated atrial electrograms (CFAEs). We aimed to study the prediction of the CFAEs defined by an automatic algorithm in different atrial substrates (high voltage areas vs low voltage areas). Methods and Results: This study included 13 patients (age = 56 ± 12 years, paroxysmal AF = 8 and persistent AF = 5), who underwent mapping and catheter ablation of AF with a NavX system. High‐density voltage mapping of the left atrium (LA) was performed during sinus rhythm (SR) (248 ± 75 sites per patient) followed by that during AF (88 ± 24 sites per patient). The CFAE maps were based on the automatic‐detection algorithm. “Operator‐determined CFAEs” were defined according to Nademannee's criteria. A low‐voltage zone (LVZ) was defined as a bipolar voltage of less than 0.5 mV during SR. Among a total of 1150 mapping sites, 459 (40%) were categorized as “operator‐determined CFAE sites,” whereas 691 (60%) were categorized as “operator‐determined non‐CFAE sites.” The sensitivity and negative predictive value increased as the fractionated interval (FI) value of the automatic algorithm increased, but the specificity and positive predictive value decreased. The automatic CFAE algorithm exhibited the highest combined sensitivity and specificity with an FI of <60 ms for the sites inside the LVZ and FI < 70 ms for the sites outside the LVZ, when compared with a single threshold for both the high‐ and low‐voltage groups combined (i.e., no regard for voltage) (ROC: 0.89 vs 0.86). Conclusions: The clinical relevance of the CFAE map would be improved if the calculated index values were accordingly scaled by the electrogram peak‐to‐peak amplitude. (J Cardiovasc Electrophysiol, Vol. 21, pp. 21–26, January 2010)
Safety and Efficacy of Bivalirudin in High‐risk Patients Admitted Through the Emergency Department
Authors: Miller Chadwick D. , Blomkalns Andra L. , Gersh Bernard J. , Pollack Charles V. , Brogan Gerard X. , Diercks Deborah B. , Frank Peacock W. , Stone Gregg W. , Hollander Judd E. , Manoukian Steven V. , Hoekstra James W. ,   on behalf of the ACUITY Investigators
Published: July 2009

AbstractObjectives:  The objective was to assess the safety and efficacy of bivalirudin monotherapy in patients with high‐risk acute coronary syndrome (ACS) presenting to the emergency department (ED).Methods:  Data from the Acute Catheterization and Urgent Intervention Triage StrategY (ACUITY) trial were used to conduct a post hoc subgroup analysis of high‐risk ACS patients (cardiac biomarker elevation or ST‐segment deviation) who initially presented to the ED. The ACUITY trial randomized patients to receive heparin (unfractionated [UFH] or enoxaparin) plus glycoprotein IIb/IIIa inhibition (GPI), bivalirudin plus GPI, or bivalirudin monotherapy. Endpoints included composite ischemia, major bleeding (not coronary artery bypass graft (CABG) related), and net clinical outcome (major bleeding plus composite ischemia).Results:  Of 13,819 participants in the ACUITY trial, 6,441 presented initially to the ED, met high‐risk criteria, and were included in the primary analysis. Bivalirudin alone when compared to heparin plus GPI, after adjusting for covariates, was associated with an improvement in net clinical outcome (12.3% vs. 14.3%, adjusted odds ratio [OR] = 0.81, 95% confidence interval [CI] = 0.66 to 0.99), similar composite ischemia (9.3% vs. 9.1%, adjusted OR = 0.98, 95% CI = 0.77 to 1.24), and less major bleeding (4.0% vs. 6.8%, adjusted OR = 0.57, 95% CI = 0.42 to 0.75). Bivalirudin plus GPI when compared to heparin plus GPI had similar net clinical outcome (13.8% vs. 14.3%, adjusted OR = 0.91, 95% CI = 0.75 to 1.11), composite ischemia (8.8% vs. 9.1%, adjusted OR = 0.87, 95% CI = 0.69 to 1.11), and major bleeding (6.8% vs. 6.8%, adjusted OR = 1.01, 95% CI = 0.79 to 1.30).Conclusions: Bivalirudin monotherapy decreases major bleeding while providing similar protection from ischemic events compared to heparin plus GPI in patients with high‐risk ACS admitted through the ED.
Perceived Challenges to Obtaining Informed Consent for a Time‐sensitive Emergency Department Study of Pediatric Status Epilepticus: Results of Two Focus Groups
Authors: Chamberlain James M. , Lillis Kathleen , Vance Cheryl , Brown Kathleen M. , Fawumi Olubunmi , Nichols Shari , Davis Colleen O. , Singh Tasmeen , Baren Jill M. ,   the Pediatric Emergency Care Applied Research Network (PECARN)
Published: July 2009

AbstractObjectives:  The objective was to describe the perspective of research personnel on issues of informed consent in a time‐sensitive clinical study under emergency circumstances.Methods:  The authors convened concurrent focus groups of research staff and investigators involved in a pharmacokinetic study of lorazepam for status epilepticus (SE). Moderators led discussion with open‐ended questions on selected issues of parental consent, communication and understanding, patient assent, and comparison to other types of studies. Focus group transcripts were analyzed to identify themes and subthemes from the discussions.Results:  Most themes and subthemes were identified in both research staff and investigator focus groups. Focus group discussion points were categorized into three main themes: barriers to and enablers of informed consent, barriers to and enablers of actual enrollment, and overall ethical concerns about the research. Many of the issues identified were unique to emergency research.Conclusions:  From the perspectives of research staff and investigators enrolling patients in a time‐sensitive emergency department study, the authors identified several areas of concern that should be addressed when planning future emergency studies.
Emergency Physician High Pretest Probability for Acute Coronary Syndrome Correlates with Adverse Cardiovascular Outcomes
Authors: Chandra Abhinav , Lindsell Christopher J. , Limkakeng Alexander , Diercks Deborah B. , Hoekstra James W. , Hollander Judd E. , Douglas Kirk J. , Frank Peacock W. , Brian Gibler W. , Pollack Charles V. ,   on behalf of the EMCREG i*trACS Investigators
Published: July 2009

AbstractObjectives:  The value of unstructured physician estimate of risk for disease processes, other than acute coronary syndrome (ACS), has been demonstrated. The authors sought to evaluate the predictive value of unstructured physician estimate of risk for ACS in emergency department (ED) patients without obvious initial evidence of a cardiac event.Methods:  This was a post hoc secondary analysis of the Internet Tracking Registry for Acute Coronary Syndromes (i*trACS), a prospectively collected multicenter data registry of patients over the age of 18 years presenting to the ED with symptoms of ACS between 1999 and 2001. In this registry, following patient history, physical exam, and electrocardiogram (ECG), the unstructured treating physician estimate of risk was recorded. A 30‐day follow‐up and a medical record review were used to determine rates of adverse cardiac events, death, myocardial infarction (MI), or revascularization procedure. The analysis included all patients with nondiagnostic ECG changes, normal initial biomarkers, and a non‐MI initial impression from the registry and excluded those without complete data or who were lost to follow‐up. Data were stratified by unstructured physician risk estimate: noncardiac, low risk, high risk, or unstable angina.Results:  Of 15,608 unique patients in the registry, 10,145 met inclusion/exclusion criteria. Patients were defined as having unstable angina in 6.0% of cases; high risk, 23.5% of cases; low risk, 44.2%; and noncardiac, 26.3% of cases. Adverse cardiac event rates had an inverse relationship, decreasing from 22.0% (95% confidence interval [CI] = 18.8% to 25.6%) for unstable angina, 10.2% (95% CI = 9.0% to 11.5%) for those stratified as high risk, 2.2% (95% CI = 1.8% to 2.6%) for low risk, and to 1.8% (95% CI = 1.4% to 2.4%) for noncardiac. The relative risk (RR) of an adverse cardiac event for those with an initial label of unstable angina compared to those with a low‐risk designation was 10.2 (95% CI = 8.0 to 13.0). The RR of an event for those with a high‐risk initial impression compared to those with a low‐risk initial impression was 4.7 (95% CI = 3.8 to 5.9). The risk of an event among those with a low‐risk initial impression was the same as for those with a noncardiac initial impression (RR = 0.83, 95% CI = 0.6 to 1.2).Conclusions:  In ED patients without obvious initial evidence of a cardiac event, unstructured emergency physician (EP) estimate of risk correlates with adverse cardiac outcomes.