[Outcomes of catheter ablation of atrial fibrillation in patients over 65 years of age]. / Výsledky katetrové ablace fibrilace síní u pacientu nad 65 let.

PURPOSE: This study assessed ablation techniques, recurrent arrhythmias, long-term outcomes, and complications of catheter ablation for atrial fibrillation (AF) in patients 65 years of age. METHODS: Consecutive patients aged < 65 years (n = 653) vs 65 years (n = 213), who underwent catheter ablation of AF in the course of eight years, were compared. Ablation strategy and procedure endpoints were left at the operators discretion. RESULTS: The group of patients 65 years comprised more females (p < 0.001), and more frequently presented with persistent AF (p = 0.010). These patients less frequently underwent simple pulmonary vein isolation (p = 0.017); on the contrary, extensive ablation including coronary sinus intervention was more common (p = 0.020). There was no difference in repeat ablation procedures (25 % vs 26 % patients; p = 0.823, or 1.4 vs 1.5 ablation procedures/1 patients; p = 0.479, respectively). Spectrum of recurrent arrhythmias did not differ between the groups except for more frequent paroxysmal AF before the first repeat ablation in patients < 65 years (p = 0.050). At the end of 49 ± 26 month total follow-up, stable sinus rhythm (SR) was achieved in 85 % patients < 65 years vs 76 % patients 65 years (p = 0.318). To maintain stable SR, older patients more often continued to take antiarrhythmic medication (p = 0.054). More serious complication occurred in 3.8 % of the patients 65 years vs 2.1 % of the patients < 65 years of age (p = 0.207). CONCLUSION: Patients 65 years of age achieved insignificantly worse long-term outcome after insignificantly fewer repeat ablation procedures, and with more frequent use of antiarrhythmic drugs. SR maintenance and risk of complications were, however, favorable.

[Catheter ablation of atrio-ventricular accessory pathways in the era of ablation therapy of complex arrhythmias: a changing perspective for oncoming generation of electrophysiologists]. / Katetrová ablace atrioventrikulárních prídatných drah v ére ablacní lécby komplexních arytmií: menící se perspektiva pro nastupující generaci elektrofyziologu

INTRODUCTION: Catheter ablation of atrio-ventricular accessory pathways has become a routine treatment method. However, its perspective has been changing in the era of ablation of complex arrhythmias. This study was aimed at evaluating accessory pathways ablation efficacy within the last nine years at one center. METHODS: From February 2002 to June 2011, catheter ablation of accessory pathways was performed in 247 patients (100 females, 42 ± 16 years). Elimination of accessory pathways conduction in both directions was the procedure endpoint. RESULTS: Immediate accessory pathways conduction elimination at the first ablation was achieved in 228 (92%) patients. Ablation failed to eliminate accessory pathways conduction in 19 (8%) patients, or accessory pathways conduction subsequently recurred in another 7 (3%) patients. Repeat ablation was completed in 20 (8%) patients, 2 patients underwent a third ablation procedure. In total, accessory pathway was permanently eliminated in 238 (96%) patients. Ablation failure was connected with a risky position in the vicinity of atrio-ventricular conduction system in 6 (67 %) out of 9 patients. By the individual A, B, C, D operators experience, efficacy of the first procedure/total efficacy, was 97%/99%, 90%/96%, 87%/87%, and 91%/91%, respectively (comparison of inter-operator efficacy of the first and repeat ablation by Kruskal-Wallis ANOVA test: p = 0,19 and 0,05, respectively). CONCLUSION: Accessory pathways ablation efficacy exceeds 95%, and ablation failure is dominantly related to the accessory pathways location close to the atrio-ventricular conduction system. Individual operator's experience was associated with a certain disparity between high and nearly absolute accessory pathways ablation efficacy.

Kinetic Analyses of Desulfurization of Dibenzothiophene by Rhodococcus erythropolis in Continuous Cultures.

Rhodococcus erythropolis N1-36, a desulfurization strain, was grown in continuous culture at 10 different dilution rates with 50 (mu)M dibenzothiophene sulfone (DBTO(inf2)) as the growth-limiting nutrient. The steady-state biomass, concentrations of substrate (DBTO(inf2)) and product (monohydroxybiphenyl), saturation constant (0.39 (mu)M DBTO(inf2)), and cell yield coefficient (9 mg of biomass(middot)(mu)M(sup-1) DBTO(inf2)) were measured. Continuous cultures at five temperatures allowed calculation of activation energy (0.84 kcal(middot)mol(sup-1) [ca. 3.5 kJ(middot)mol(sup-1)]) near the optimal temperature (30(deg)C) for growth. A washout technique was used to calculate the maximum specific growth rate (0.235 h(sup-1)), a value equivalent to a minimum generation time of 2.95 h.

Kinetic Analyses of Desulfurization of Dibenzothiophene by Rhodococcus erythropolis in Batch and Fed-Batch Cultures.

The DbtS(sup+) phenotype (which confers the ability to oxidize selectively the sulfur atom of dibenzothiophene [DBT] or dibenzothiophene sulfone [DBTO(inf2)]) of Rhodococcus erythropolis N1-36 was quantitatively characterized in batch and fed-batch cultures. In flask cultures, production of the desulfurization product, monohydroxybiphenyl (OH-BP), was maximal at pH 6.0, while specific productivity (OH-BP cell(sup-1)) was maximal at pH 5.5. Quantitative measurements in fermentors (in both batch and fed-batch modes) demonstrated that DBTO(inf2) as the sole sulfur source yielded a greater amount of product than did DBT. Specifically, 100 (mu)M DBT maximally yielded (apprx=)40 (mu)M OH-BP, while 100 (mu)M DBTO(inf2) yielded (apprx=)60 (mu)M OH-BP. Neither maintaining the pH at 6.0 nor adding an additional carbon source increased the yield of OH-BP. The presence of SO(inf4)(sup2-) in growth media repressed expression of desulfurization activity, but SO(inf4)(sup2-) added to suspensions of cells grown in DBT or DBTO(inf2) did not inhibit desulfurization activity.

Organization of the bacterial chromosome.

Recent progress in studies on the bacterial chromosome is summarized. Although the greatest amount of information comes from studies on Escherichia coli, reports on studies of many other bacteria are also included. A compilation of the sizes of chromosomal DNAs as determined by pulsed-field electrophoresis is given, as well as a discussion of factors that affect gene dosage, including redundancy of chromosomes on the one hand and inactivation of chromosomes on the other hand. The distinction between a large plasmid and a second chromosome is discussed. Recent information on repeated sequences and chromosomal rearrangements is presented. The growing understanding of limitations on the rearrangements that can be tolerated by bacteria and those that cannot is summarized, and the sensitive region flanking the terminator loci is described. Sources and types of genetic variation in bacteria are listed, from simple single nucleotide mutations to intragenic and intergenic recombinations. A model depicting the dynamics of the evolution and genetic activity of the bacterial chromosome is described which entails acquisition by recombination of clonal segments within the chromosome. The model is consistent with the existence of only a few genetic types of E. coli worldwide. Finally, there is a summary of recent reports on lateral genetic exchange across great taxonomic distances, yet another source of genetic variation and innovation.

Acquisitive evolution of ribitol dehydrogenase in Klebsiella pneumoniae.

Selection in continuous culture of Klebsiella pneumoniae mutants that have gained the ability to utilize xylitol while also retaining regulatory control over ribitol utilization was achieved with a dual-substrate regime. Initial steady-state cultures of wild-type organisms were maintained with 0.005% (0.329 mM) ribitol. Mutants of various types proliferated when the composition of the limiting medium was changed to 0.005% ribitol plus 0.250% (16.43 mM) xylitol.

The orderly, in vitro emergence of DNA from bacteriophage phi29 particles.

phi29 DNA-containing 12-13- particles (produced by infecting nonsuppressor hosts of Bacillus subtilis with phage containing suppressible mutations in cistrons 12 and 13) can be complemented with lysates containing proteins p12* and p13 to yield infectious phage. Complementation of these particles with lysates containing p12* but not p13 or complementation with purified p12* in the absence of p13 produces a structure (called complex) which has a markedly different organization. Electron microscopy and sedimentation analysis after digestion with DNase I or proteinase K indicate that complex is composed of an intact phage head with a genome-sized linear DNA molecule attached at the collar-tail region. EcoRI digestion establishes that the DNA molecule has a unique orientation. Gel electrophoresis indicates that p12*, the neck appendage protein, is transferred to the particles when complex is formed. Complex can also be produced by incubation of 12-13- particles at 42 degrees , by incubation at pH 6.0, or by incubation in the presence of 20 mM EDTA. Complex is also formed from DNA-containing 12- particles but to a lesser extent.

Temperature characteristics and Arrhenius plots for nominal psychrophiles, mesophiles and thermophiles.

The specific growth rates at various temperatures of 12 bacterial species were measured and plotted as Arrhenius profiles. Temperature characteristics and optimum temperatures for maximum specific growth rates were estimated from these curves. The data reveal that one of two forms of the Arrhenius profile is characteristic of each bacterium: one curve is a simple smooth curve with a single predominant slope at sub-optimum temperatures; the other is a more complex curve with two distinct slopes at sub-optimum temperatures. The simple curves describes bacteria across the entire biokinetic range whereas the more complex curve occurs only with organisms which have optimum temperatures for replication above 37 degrees C. Describing bacteria in terms of these forms of the Arrhenius profile is less arbitrary than is categorization based on optimum temperatures.