Mutation in nuclear pore component NUP155 leads to atrial fibrillation and early sudden cardiac death.

Atrial fibrillation (AF) is the most common form of sustained clinical arrhythmia. We previously mapped an AF locus to chromosome 5p13 in an AF family with sudden death in early childhood. Here we show that the specific AF gene underlying this linkage is NUP155, which encodes a member of the nucleoporins, the components of the nuclear pore complex (NPC). We have identified a homozygous mutation, R391H, in NUP155 that cosegregates with AF, affects nuclear localization of NUP155, and reduces nuclear envelope permeability. Homozygous NUP155(-/-) knockout mice die before E8.5, but heterozygous NUP155(+/-) mice show the AF phenotype. The R391H mutation and reduction of NUP155 are associated with inhibition of both export of Hsp70 mRNA and nuclear import of Hsp70 protein. These human and mouse studies indicate that loss of NUP155 function causes AF by altering mRNA and protein transport and link the NPC to cardiovascular disease.

Radiofrequency Ablation with an Enhanced-Irrigation Flexible-Tip Catheter versus a Standard-Irrigation Rigid-Tip Catheter.

BACKGROUND: The flexible-tip irrigated ablation catheter Cool Flex™ (St. Jude Medical, St. Paul, MN, USA) was introduced to enhance cooling of the catheter-tissue interface and to conform to endocardial surface with better contact. Little is known about the performance of such catheter design compared to the widely used rigid-tip catheters. METHODS: In a thigh muscle preparation, ablation using the flexible-tip and rigid-tip catheters was performed in seven pigs across a range of ablation settings and catheter orientation. Postprocedure, the thigh muscle was stained with 2,3,5-triphenyltetrazolium-chloride injected into the femoral artery. The muscle was excised, fixed with formalin, and examined grossly. RESULTS: A total of 196 lesions (95 flexible tip, 101 rigid tip) were evaluated. The flexible-tip catheter was associated with enhanced cooling of catheter-tissue interface (31.1 ± 3.3°C vs 36.3 ± 3.7°C, P = 0.0001) in both perpendicular and nonperpendicular catheter orientations. This allowed more energy delivery (37.3 ± 8.9 W vs 33.7 ± 8.1 W, P = 0.004) to targeted tissue and resulted in larger lesions (median 194.7 [interquartile range: 113.1-333.8] mm(3) vs 170.9 [88.7-261.6] mm(3) , P = 0.03) than the rigid-tip catheter with larger maximum diameter (11.1 ± 2.6 mm vs 10.3 ± 2.1 mm, P = 0.03) and larger diameter at tissue surface (10.3 ± 2.4 mm vs 9.6 ± 1.7 mm, P = 0.01). Catheter orientation during ablation affected the efficiency of rigid-tip but not the flexible-tip catheter. The use of the flexible-tip catheter was associated with significantly less char formation on tissue (none vs 5.1% with rigid tip, P = 0.009). CONCLUSION: The Cool Flex™ catheter performed better than a rigid-tip catheter with enhanced cooling, larger ablation lesions, and no charring of targeted tissue.

Downstream coronary effects of drug-eluting stents.

BACKGROUND: Antiproliferative agents used in drug-eluting stents (DES) attenuate atherosclerosis, yet DES implantation has been linked to endothelial dysfunction. The downstream effects of DES on new lesion formation have not been previously directly examined. We sought to compare the development of de novo stenoses and need for treatment in the downstream coronary vessel of patients treated with DES or a bare-metal stent. METHODS: Angiographic images and procedural information were prospectively collected on 463 adults who underwent implantation of a single stent in a proximal coronary artery, had an appropriate control vessel for comparison, and subsequently returned for intervention. Propensity matching identified 89 pairs of patients. End points were defined as angiographic identification of a de novo stenosis or need for secondary intervention in the downstream vessel within 12 months of initial intervention. RESULTS: In the overall (P < .01) and propensity-matched cohort (P = .01), there was reduced risk of new lesions downstream to DES. No difference was seen in respective control vessels (P = .14 and P = .99). A reduced need for downstream intervention with DES was seen in both the overall (P = .01) and propensity-matched cohorts (P = .04). No difference was seen in the control vessels (P = .98 and P = .36). Multivariate proportional hazards modeling of known atherosclerosis risk factors identified stent type as the sole predictor for downstream lesions (P < .01) and downstream events (P = .02). CONCLUSIONS: Patients receiving DES appear less likely to develop downstream stenoses and events compared with patients receiving bare-metal stents, suggesting beneficial downstream drug delivery.

Assessing the ecological risk of active principles used currently by freshwater fish farms.

The global aquaculture industry has grown exponentially in recent years using to control of infections and diseases, a variety of veterinary drugs (VMP) are used, including antibiotics, antifungals and antiparasitics, which have different routes of emission, environmental persistence and side effects to aquatic organisms, becoming one of the main concerns in its use of veterinary drugs (VMP) and its potential toxicological impact on the environment, in this context, Chile is considered one of the main salmon producers. Ecological risk assessment of active principles used infreshwater fish farms worldwide and in Chile were investigated. We recollect a physical - chemical properties of active principles used by fish farms and we could estimate the relative hazard a priori. Later active principles grouped as antibiotics (n = 6), antiparasitics (n = 5), anesthetics (n = 3), and disinfectants (n = 7) were assessed using a mass balance model based on fugacity was developed for each active principle under treatments via immersion and food administration in fish, while a volumetric model for disinfectants and sodium chloride was used for estimating the predicted environmental concentration (PEC), under a real smolt farming scenario in fish farms. Ecotoxicological data were collected from open literature to predict the no-effect concentration (PNEC). The ecological risk assessment was characterized using a risk quotient (RQ = PEC/PNEC) based in two assessment tiers. Results revealed that 12 active ingredients showed a high risk (RQ ≥ 1), thus indicating that adverse effects could occur and further investigation with measured concentrations in the field are required to reduce exposure in surface waters.

High-resolution melting of the cytochrome B gene in fecal DNA: A powerful approach for fox species identification of the Lycalopex genus in Chile.

Easy, economic, precise species authentication is currently necessary in many areas of research and diagnosis in molecular biology applied to conservation studies of endangered species. Here, we present a new method for the identification of three fox species of the Lycalopex genus in Chile. We developed an assay based on high-resolution melt analysis of the mitochondrial cytochrome B gene, allowing a simple, low cost, fast, and accurate species determination. To validate the assay applicability for noninvasive samples, we collected fecal samples in the Atacama Desert, finding unexpectedly one species outside of its known distribution range. We conclude that the assay has a potential to become a valuable tool for a standardized genetic monitoring of the Lycalopex species in Chile.

Protective effect of KCNH2 single nucleotide polymorphism K897T in LQTS families and identification of novel KCNQ1 and KCNH2 mutations.

BACKGROUND: KCNQ1 and KCNH2 are the two most common potassium channel genes causing long QT syndrome (LQTS), an inherited cardiac arrhythmia featured by QT prolongation and increased risks of developing torsade de pointes and sudden death. To investigate the disease expressivity, this study aimed to identify mutations and common variants that can modify LQTS phenotype. METHODS: In this study, a cohort of 112 LQTS families were investigated. Among them two large LQTS families linkage analysis with markers spanning known LQTS genes was carried out to identify the specific gene for mutational analysis. All exons and exon-intron boundaries of KCNH2 and KCNQ1 were sequenced for mutational analysis. RESULTS: LQTS-associated mutations were identified in eight of 112 families. Two novel mutations, L187P in KCNQ1 and 2020insAG in KCNH2, were identified. Furthermore, in another LQTS family we found that KCNH2 mutation A490T co-segregated with a common SNP K897T in KCNH2. KCNH2 SNP K897T was reported to exert a modifying effect on QTc, but it remains controversial whether it confers a risk or protective effect. Notably, we have found that SNP K897T interacts with mutation A490T in cis orientation. Seven carriers for A490T and the minor allele T of SNP K897T showed shorter QTc and fewer symptoms than carriers with A490T or A490P (P < 0.0001). CONCLUSION: Our family-based approach provides support that KCNH2 SNP K897T confers a protective effect on LQTS patients. Our study is the first to investigate the effect of SNP K897T on another KCNH2 mutation located in cis orientation. Together, our results expand the mutational and clinical spectrum of LQTS and provide insights into the factors that determine QT prolongation associated with increased risk of ventricular tachycardia and sudden death.

[A Novel mutation of F189L in CASQ2 in families with catecholaminergic polymorphic ventricular tachycardia].

OBJECTIVE: To identify mutations and variants in CASQ2 gene in 27 CPVT patients/family members. METHODS: Mutational analysis was performed with direct DNA sequence analysis. The frequency of an identified CASQ2 variant was determined using the Taqman genotyping assay. RESULTS: A novel heterozygous mutation, F189L, in CASQ2 gene was identified in one family with CPVT. This mutation occurred at the evolutionarily, highly conserved phenylalanine residue at codon 189, and was not present in 1400 control individuals. No other disease-causing mutations were identified in the CASQ2 gene. CONCLUSION: A novel mutation of F189L in the CASQ2 gene was identified.

A Treatment Planning Study of Stereotactic Body Radiotherapy for Atrial Fibrillation.

PURPOSE:  To explore the feasibility of using stereotactic body radiotherapy (SBRT) to irradiate the antra of the four pulmonary veins while protecting nearby critical organs, such as the esophagus. MATERIALS AND METHODS:  Twenty patients who underwent radiofrequency catheter ablation for atrial fibrillation were selected. For each patient, the antra of the four pulmonary veins were identified as the target volumes on a pre-catheterization contrast or non-contrast CT scan. On each CT scan, the esophagus, trachea, heart, and total lung were delineated and the esophagus was identified as the critical organ. For each patient, three treatment plans were designed with 0, 2, and 5 mm planning margins around the targets while avoiding overlap with a planning organ at risk volume (PRV) generated by a 2 mm expansion of the esophagus. Using three non-coplanar volumetric modulated arcs (VMAT), 60 plans were created to deliver a prescription dose of 50 Gy in five fractions, following the SBRT dose regimen for central lung tumors. With greater than 97% of the planning target volumes (PTV) receiving the prescription doses, we examined dosimetry to 0.03 cc and 5 cc of the esophagus PRV volume as well as other contoured structures. RESULTS: The average PTV-0 mm, PTV-2 mm, and PTV-5 mm volumes were 3.05 ± 1.90 cc, 14.70 ± 5.00 cc, and 40.85 ± 10.20 cc, respectively. With three non-coplanar VMAT arcs, the average conformality indices (ratio of prescription isodose volume to the PTV volume) for the PTV-0 mm, PTV-2 mm and PTV-5 mm were 4.81 ± 2.0, 1.71 ± 0.19, and 1.23 ± 0.08, respectively. Assuming patients were treated under breath-hold with 2 mm planning margins to account for cardiac motion, all plans met esophageal PRV maximum dose limits < 50 Gy to 0.03 cc and 16 plans (80%) met < 27.5 Gy to 5 cc of the esophageal PRVs. For PTV-5 mm plans, 18 plans met the maximum dose limit < 50 Gy to 0.03 cc and only two plans met the maximum dose limit < 27.5 Gy to 5 cc of the esophageal PRV. CONCLUSIONS: The anatomical relationship between the antra of the four pulmonary veins and the esophagus varies from patient to patient. Adding 2 mm planning margins and a 2 mm PRV to the esophagus can meet the dose constraints developed for SBRT central lung tumors. Future studies are needed to validate the safety and efficacy of the planning dose, tolerance dose to normal cardiac tissue, and adequate planning margins.

Genome-wide linkage scan identifies a novel genetic locus on chromosome 5p13 for neonatal atrial fibrillation associated with sudden death and variable cardiomyopathy.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and patients with AF have a significantly increased risk for ischemic stroke. Approximately 15% of all strokes are caused by AF. The molecular basis and underlying mechanisms and pathophysiology of AF remain largely unknown. METHODS AND RESULTS: We have identified a large AF family with an autosomal recessive inheritance pattern. The AF in the family manifests with early onset at the fetal stage and is associated with neonatal sudden death and, in some cases, ventricular tachyarrhythmias and waxing and waning cardiomyopathy. Genome-wide linkage analysis was performed for 36 family members and generated a 2-point logarithm of the odds (LOD) score of 3.05 for marker D5S455. The maximum multipoint LOD score of 4.10 was obtained for 4 markers: D5S426, D5S493, D5S455, and D5S1998. Heterozygous carriers have significant prolongation of P-wave duration on ECGs compared with noncarriers (107 versus 85 ms on average; P=0.000012), but no differences between these 2 groups were detected for the PR interval, QRS complex, ST-segment duration, T-wave duration, QTc, and R-R interval (P>0.05). CONCLUSIONS: Our findings demonstrate that AF can be inherited as an autosomal recessive trait and define a novel genetic locus for AF on chromosome 5p13 (arAF1). A genetic link between AF and prolonged P-wave duration was identified. This study provides a framework for the ultimate cloning of the arAF1 gene, which will increase the understanding of the fundamental molecular mechanisms of atrial fibrillation.

Modificaciones ultraestructurales del endometrio inducidas por dispositivos intrauterinos (DIU) / Ultrastructural modifications of the endometrium due to intrauterine devices

The exact nature of the mechanism of action of intrauterine devices (IUDs) is not known yet, in spite of numerous studies made to ascertain the effects of the devices. The assumption that the foreign body might induce microscopic changes capable of altering the biochemical behavior of the endometrium induced us to study the problem from the morphological viewpoint. thus, a study was performed on 20 yound IUD wearers for periods of 12 to 36 months. The IUDs used were either inert or medicated poliethylene. For this purpose, 2 mm3 samples of endometrium obtained through control biopsies were studied were studied by light microscopy and transmission (TEM) and scanning (SEM) electron microscopy. Controls were obtained from normal endometrium in either the middle or secretory stage of the cycle. The aim was to investigate ephithelial and stromal changes possibli related with the presence of inert or medicated IUDs. Light microscopy and SEM offer similar images: a flat ephithelium devoid of cilia, and areas with exfoliated epithelium, leaving the basal membrane in direct contact with the uterine cavity. An early predecidualization of the stroma is observed. Under TEM, the main changes were located in the cell organelles: decrease of microvilli, degenerative chagnes of mitochondria, vesiculation of citoplasmic membranes. In the stroma, predecidual cells and granulocytes were observed. Based on our observations it may be concluded that IUDs create unfavorable envronmental conditions for blastocystic attachment where apaprently no dislodgement of the implanted ovum occuts. Its action seems to be contraceptive rather than abortifacient in the usual sense

Inervación propioceptiva en ligamentos de la rodilla del gato / Innervation of the ligament of the knee joint in the cat

The proprioceptive receptors are important nerve endings that are found mainly at musculotendinous junctions, ligaments and capsules of the articular joints. Their importance is linked with the fact that they provide the sensory-motor feedback for neurmuscular control. Therefore, more accurate inofrmation on the type, number and regenerative capacity of mechanoreceptors is of great value in traumatology. We studied the neuroanatomical structure of these receptors in cat knee ligaments, by means of metalic impregnation methods. This first communication contains our results with gold chloride. The motor end plates and neuromuscular spindles of tenuissimus muscle of the cat were employed for testing method modifications. This allowed us to reproduce results. The connective septa of collagen bundles show nerves containing 20 to 30 nerve fibers of the myelinic as well as amyelinic type; besides, free endings, branched or elongated structures resembling glomeruli, and corpuscles were observed. Free endings are very rare, and are found only next to blood vessels, whereas branched endings appear as spirals located between fat cells. Some coiled nerve fibres were observed on the surface of collagen fibers. Corpuscles of Ruffini are also presente at the connective septa. In general terms, a great variety in the structure of the receptors was observed. Our description of specific populations of nerve endings in car knee ligaments suggests that they do contribute to the afferent discharge providing information to the initiation of protective reflexs