Comparing phase and electrographic flow mapping for persistent atrial fibrillation.

BACKGROUND: An increasing number of methods are being used to map atrial fibrillation (AF), yet the sensitivity of identifying potential localized AF sources of these novel methods are unclear. Here, we report a comparison of two approaches to map AF based upon (1) electrographic flow mapping and (2) phase mapping in a multicenter registry of patients in whom ablation terminated persistent AF. METHODS: Fifty-three consecutive patients with persistent AF in whom ablation terminated AF in an international multicenter registry were enrolled. Electrographic flow mapping (EGF) and phase mapping were applied to the multipolar simultaneous electrograms recorded from a 64-pole basket catheter in the chamber (left vs right atrium) where AF termination occurred. We analyzed if the mapping methods were able to detect localized sources at the AF termination site. We also analyzed global results of mapping AF for each method, patterns of activation of localized sources. RESULTS: Patients were 64.3 ± 9.4 years old and 69.8% were male. EGF and phase mapping identified localized sources at AF termination sites in 81% and 83% of the patients, respectively. Methods were complementary and in only n = 2 (3.7%) neither method identified a source. Globally, EGF identified more localized sources than phase mapping (5.3 ± 2.8 vs 1.8 ± 0.5, P < 0.001), with a higher prevalence of focal (compared to rotational) activation pattern (49% vs 2%, P < 0.01). CONCLUSIONS: EGF is a novel vectorial-based AF mapping method, which can detect sites of AF termination, agreeing with, and complementary to, an alternative AF mapping method using phase analysis.

Integrated genetic and morphological data support eco-evolutionary divergence of Angolan and South African populations of Diplodus hottentotus.

The genus Diplodus presents multiple cases of taxonomic conjecture. Among these the D. cervinus complex was previously described as comprising three subspecies that are now regarded as separate species: Diplodus cervinus, Diplodus hottentotus and Diplodus omanensis. Diplodus hottentotus exhibits a clear break in its distribution around the Benguela Current system, prompting speculation that Angolan and South African populations flanking this area may be isolated and warrant formal taxonomic distinction. This study reports the first integrated genetic [mitochondrial (mt)DNA and nuclear microsatellite] and morphological (morphometric, meristic and colouration) study to assess patterns of divergence between populations in the two regions. High levels of cytonuclear divergence between the populations support a prolonged period of genetic isolation, with the sharing of only one mtDNA haplotype (12 haplotypes were fully sorted between regions) attributed to retention of ancestral polymorphism. Fish from the two regions were significantly differentiated at a number of morphometric (69·5%) and meristic (46%) characters. In addition, Angolan and South African fish exhibited reciprocally diagnostic colouration patterns that were more similar to Mediterranean and Indian Ocean congeners, respectively. Based on the congruent genetic and phenotypic diversity we suggest that the use of hottentotus, whether for full species or subspecies status, should be restricted to South African D. cervinus to reflect their status as a distinct species-like unit, while the relationship between Angolan and Atlantic-Mediterranean D. cervinus will require further demo-genetic analysis. This study highlights the utility of integrated genetic and morphological approaches to assess taxonomic diversity within the biogeographically dynamic Benguela Current region.

Selective serotonin reuptake inhibitors and myocardial infarction.

BACKGROUND: Depression is an independent risk factor for myocardial infarction (MI). Selective serotonin reuptake inhibitors (SSRIs) may reduce this risk through attenuation of serotonin-mediated platelet activation in addition to treatment of depression itself. METHODS AND RESULTS: case-control study of first MI in smokers 30 to 65 years of age was conducted among all 68 hospitals in an 8-county area during a 28-month period. Cases were patients hospitalized with a first MI. Approximately 4 community control subjects per case were randomly selected from the same geographic area using random digit dialing. Detailed information regarding use of antidepressant medication as well as other clinical and demographic data were obtained by telephone interview. A total of 653 cases of first MI and 2990 control subjects participated. After adjustment, using multivariable logistic regression, for age, sex, race, education, exercise, quantity smoked per day, body mass index, aspirin use, family history of MI, number of physician encounters, and history of coronary disease, diabetes, hypertension, or hypercholesterolemia, the odds ratio for MI among current SSRI users compared with nonusers was 0.35 (95% CI 0.18, 0.68; P<0.01). Non-SSRI antidepressant users had a nonsignificant reduction in MI risk with wide confidence intervals (adjusted odds ratio 0.48, CI 0.17, 1.32; P=0.15). However, analysis of this group was limited by the small number of exposed subjects. CONCLUSIONS: The use of SSRIs may confer a protective effect against MI. This could be attributable to the inhibitory effect SSRIs have on serotonin-mediated platelet activation or possibly amelioration of other factors associated with increased risk for MI in depression.

Choreography of the squid's "nuptial dance".

A mass spawning of squid resembles, at first glance, a chaotic "nuptial dance" (1). But for the first time, we have applied 3-D, radio-linked acoustic positioning (RAP) to this confusing process, and our early results now reveal a choreography that is, in fact, well organized in time and space. Remote tracking with RAP of individual Loligo vulgaris reynaudii off South Africa has provided insights into the daily sequence of behaviours that lead these animals to aggregate for sexual selection. Each dawn, the squid navigate for several kilometers, towards the shore, to small, well-defined zones near egg beds on the substrate. After several hours of circling above the egg beds, a pelagic, 3-D lek-like aggregation of large males forms: females are drawn in, and the aggregation condenses as the females and males pair, mate, and lay eggs. Smaller "sneaker males" remain on the periphery of the mating arena and, from this station, attempt extra-pair copulations (EPCs). The mating system of squids is thus unexpectedly complex, rivaling those of mammals and birds (2, 3). Commercial squid-jigging fishermen in South Africa have recently been attracted to the spawning grounds, and they have been successful. Moreover, their activities may be selective for large males. Thus, attention should be devoted to ensuring that such targeted fishing does not alter the characteristics of squid population genetics. Remote tracking and video observations, in combination with genetic analyses, may offer a new opportunity to monitor mating effort and reproductive success, and thus to manage the fishery.

FXR1, an autosomal homolog of the fragile X mental retardation gene.

Fragile X mental retardation syndrome, the most common cause of hereditary mental retardation, is directly associated with the FMR1 gene at Xq27.3. FMR1 encodes an RNA binding protein and the syndrome results from lack of expression of FMR1 or expression of a mutant protein that is impaired in RNA binding. We found a novel gene, FXR1, that is highly homologous to FMR1 and located on chromosome 12 at 12q13. FXR1 encodes a protein which, like FMR1, contains two KH domains and is highly conserved in vertebrates. The 3' untranslated regions (3'UTRs) of the human and Xenopus laevis FXR1 mRNAs are strikingly conserved (approximately 90% identity), suggesting conservation of an important function. The KH domains of FXR1 and FMR1 are almost identical, and the two proteins have similar RNA binding properties in vitro. However, FXR1 and FMR1 have very different carboxy-termini. FXR1 and FMR1 are expressed in many tissues, and both proteins, which are cytoplasmic, can be expressed in the same cells. Interestingly, cells from a fragile X patient that do not have any detectable FMR1 express normal levels of FXR1. These findings demonstrate that FMR1 and FXR1 are members of a gene family and suggest a biological role for FXR1 that is related to that of FMR1.

An Ethogram of Body Patterning Behavior in the Squid Loligo vulgaris reynaudii on Spawning Grounds in South Africa.

Squids are capable of a high degree of visual signaling, most of which is expressed through the neurally controlled chromatophore organs in the skin. An accurate catalog (or ethogram) of these signals is an essential prerequisite to quantified behavioral analyses and experimentation. Body patterns such as those described here may also be useful for distinguishing between morphologically identical species or subspecies of commercial importance. The natural behavior of Loligo vulgaris reynaudii on spawning grounds was filmed by divers, and the body patterning repertoire was described in detail; 23 chromatic components, 4 postural components, and 9 locomotor components of body patterning were observed and correlated with different types of behaviors. Most of the chromatic components were expressed during intraspecific behaviors (e.g., agonistic behavior among males, courtship, mating) and, to a lesser extent, during interspecific interactions with fishes. Several of the most basic types of body patterns are described, the most distinctive of which are Lateral Display and White Flashing used between males in agonistic contests. This species is comparable to other Loligo spp. in its complexity of body patterning behavior.