Comparison of pro-atrial natriuretic peptide and atrial remodeling in marathon versus non-marathon runners

Long-term endurance sports are associated with atrial remodeling and an increased risk for atrial fibrillation (AF) and atrial flutter. Pro-atrial natriuretic peptide (pro-ANP) is a marker of atrial wall tension and elevated in patients with AF. The aim of this study was to test the hypothesis that atrial remodeling would be perpetuated by repetitive episodes of atrial stretching during strenuous competitions, reflected by elevated levels of pro-ANP. A cross-sectional study was performed on nonelite runners scheduled to participate in the 2010 Grand Prix of Bern, a 10-mile race. Four hundred ninety-two marathon and nonmarathon runners applied for participation, 70 were randomly selected, and 56 entered the final analysis. Subjects were stratified according to former marathon participations: a control group (nonmarathon runners, n = 22), group 1 (1 to 4 marathons, n = 16), and group 2 (≥5 marathons, n = 18). Results were adjusted for age, training years, and average weekly endurance training hours. The mean age was 42 ± 7 years. Compared to the control group, marathon runners in groups 1 and 2 had larger left atria (25 ± 6 vs 30 ± 6 vs 34 ± 7 ml/m(2), p = 0.002) and larger right atria (27 ± 7 vs 31 ± 8 vs 35 ± 5 ml/m(2), p = 0.024). Pro-ANP levels at baseline were higher in marathon runners (1.04 ± 0.38 vs 1.42 ± 0.74 vs 1.67 ± 0.69 nmol/L, p = 0.006). Pro-ANP increased significantly in all groups after the race. In multiple linear regression analysis, marathon participation was an independent predictor of left atrial (β = 0.427, p <0.001) and right atrial (β = 0.395, p = 0.006) remodeling. In conclusion, marathon running was associated with progressive left and right atrial remodeling, possibly induced by repetitive episodes of atrial stretching. The altered left and right atrial substrate may facilitate atrial arrhythmias.     

In vitro bactericidal effect of Nd:YAG laser on Actinomyces israelii

A bactericidal effect has been reported by the use of near-infrared laser light on both Gram-positive and Gram-negative bacteria. The aim of this study was to evaluate the effect of Nd:YAG laser on Actinomyces israelii, filamentous bacteria causing cervicofacial actinomycosis. Experiments were realized on bacterial cells in saline suspension or streaked on Mueller–Hinton (MH) agar plates with or without India ink. Laser application was performed in Eppendorf tubes with different powers and frequencies for 40 s; bacterial suspensions were then streaked on agar plates and incubated at 35 °C in proper conditions for 5 days before colony enumeration. A reduction of colony number variable from 60.13 to 100 % for powers of 2, 4, and 6 W at 25–50 Hz of frequency was observed in comparison with growth control. For agar plates, laser application was performed with different powers at 50 Hz for 60 s. A growth inhibition was observed after 5 days of incubation on MH plates with powers of 6 W and on MH–ink plates with all applied powers. This preliminary study showed a bactericidal effect caused by Nd:YAG laser application worthy to be evaluated in further experiments in vivo.     

Urticaria and its subtypes: the role of second-generation antihistamines

Urticaria is a heterogeneous group of debilitating skin disorders characterized by wheals, pruritus, and frequently angioedema. The various forms of urticaria are often chronic and can exact a toll on quality of life. New diagnostic criteria and management guidelines are available to assist primary care physicians in the identification and proper treatment of different subtypes of urticaria. Second-generation antihistamines are recommended as first-line therapy because of their high degree of efficacy and safety. It is important to note, however, that European indications for most agents in this class are limited to specific forms of urticaria. The exception is desloratadine, the only second-generation antihistamine approved for the treatment of all urticaria subtypes in the European Union. Guidelines and best practice suggest that doses of antihistamines up to 4 times higher than those normally recommended for urticaria may benefit patients who do not respond to standard doses of antihistamines. Adjunctive therapy with leukotriene receptor antagonists may be advantageous in certain subgroups of patients who have suboptimal responses to antihistamine monotherapy. In all cases, physicians should work closely with patients to ensure proper adherence to prescribed regimens—a component that is often lacking but holds the key to successful outcomes.