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Genes sharing functions, expression patterns or quantitative traits are not randomly distributed along eukaryotic genomes. In order to study the distribution of genes that share a given feature, we present Cluster Locator, an online analysis and visualization tool. Cluster Locator deter- mines the number, size and position of all the clusters formed by the protein-coding genes on a list according to a given maximum gap, the percentage of gene clustering of the list and its statistical significance. The output includes a visual representation of the distribution of genes and gene clus- ters along the reference genome.

Acromegaly is a rare disease with nonspecific symptoms with acral enlargement being almost universally present at diagnosis. The estimated prevalence is 40-125 cases/million but targeted universal screening studies have found a higher prevalence (about 10 fold). The aim of the ACROSAHS study was to investigate the prevalence of acromegaly and acromegaly comorbidities in patients with sleep apnea symptoms and acral enlargement. ACROSAHS was a Spanish prospective non-interventional epidemiological study in 13 Hospital sleep referral units. Facial and acral enlargement symptoms including: ring size and shoe size increase, tongue, lips and jaws enlargement, paresthesia or carpal tunnel syndrome and widening of tooth spaces, as well as other typical acromegaly comorbidities were recorded with a self-administered questionnaire of patients who attended a first visit for sleep apnea symptoms between 09/2013 and 07/2014. Serum insulin-like growth factor type 1 (IGF1) was measured in patients with =1 acral symptom to determine the prevalence of acromegaly. Of the 1557 patients enrolled, 1477 with complete data (72% male) were analyzed. 530 patients (36%) reported at least 1 acral enlargement symptom and were tested for IGF-1, 41 were above range, persisted in 7, and among those, 2 cases of acromegaly were diagnosed (prevalence of at least 1.35 cases/1000). Overall, 1019 patients (69%) had =2 acromegaly symptoms and should have been screened according to guidelines; moreover 373 patients (25%) had =1 symptom of acral enlargement plus =3 other acromegaly symptoms. In conclusion, in patients with sleep apnea symptoms and acral enlargement, we found an acromegaly prevalence of at least 1.35 cases per 1000 and a high prevalence of typical acromegaly symptoms. It is important that sleep specialists are aware of acromegaly symptoms to aid with acromegaly diagnosis.

If the genomic era was characterized by the massive determination of genomic sequences, the so-called postgenomic era is, among other things, characterized by a lack of methods for obtaining functionally relevant information from these raw sequences. As the number of known protein sequences grows exponentially, it is impossible to experimentally determine their biological functions and the particular regions of these proteins responsible for such functions. For this reason, computational methods that are able to process this genomic information for extracting protein functional features are sought after. © 2012 IEEE.

Comunicaciones a congresos

We report the occurrence of a bilateral pneumothoraces after unilateral central venous catheterization of the right subclavian vein in a 70-year-old patient. The patient had no history of pulmonary or pleural disease and no history of cardiothoracic surgery. Two days earlier, she had a median laparotomy under general and epidural anaesthesia. Prior to the procedure, the patient was hemodynamically stable and her transcutaneous oxygen saturation was 97% in room air. We punctured the right pleural space before cannulation of the right subclavian vein. After the procedure, the patient slowly became hemodynamically instable with respiratory distress. A chest radiograph revealed a complete left-side pneumothorax and a mild right-side pneumothorax. The right-side pneumothorax became under tension after left chest tube insertion. The symptoms finally resolved after insertion of a right chest tube. After a diagnostic work-up, we suspect a congenital “Buffalo chests” explaining bilateral pneumothoraces and a secondary tension pneumothorax.

Sticholysin I and II (St I and St II), two basic cytolysins purified from the Caribbean sea anemone Stichodactyla helianthus, efficiently permeabilize lipid vesicles by forming pores in their membranes. A general characteristic of these toxins is their preference for membranes containing sphingomyelin (SM). As a consequence, vesicles formed by equimolar mixtures of SM with phosphatidylcholine (PC) are very good targets for St I and II. To better characterize the lipid dependence of the cytolysin-membrane interaction, we have now evaluated the effect of including different lipids in the composition of the vesicles. We observed that at low doses of either St I or St II vesicles composed of SM and phosphatidic acid (PA) were permeabilized faster and to a higher extent than vesicles of PC and SM. As in the case of PC/SM mixtures, permeabilization was optimal when the molar ratio of PA/SM was ~1. The preference for membranes containing PA was confirmed by inhibition experiments in which the hemolytic activity of St I was diminished by pre-incubation with vesicles of different composition. The inclusion of even small proportions of PA into PC/SM LUVs led to a marked increase in calcein release caused by both St I and St II, reaching maximal effect at ~5 mol % of PA. Inclusion of other negatively charged lipids (phosphatidylserine (PS), phosphatidylglycerol (PG), phosphatidylinositol (PI), or cardiolipin (CL)), all at 5 mol %, also elicited an increase in calcein release, the potency being in the order CL approximately PA >> PG approximately PI approximately PS. However, some boosting effect was also obtained, including the zwitterionic lipid phosphatidylethanolamine (PE) or even, albeit to a lesser extent, the positively charged lipid stearylamine (SA). This indicated that the effect was not mediated by electrostatic interactions between the cytolysin and the negative surface of the vesicles. In fact, increasing the ionic strength of the medium had only a small inhibitory effect on the interaction, but this was actually larger with uncharged vesicles than with negatively charged vesicles. A study of the fluidity of the different vesicles, probed by the environment-sensitive fluorescent dye diphenylhexatriene (DPH), showed that toxin activity was also not correlated to the average membrane fluidity. It is suggested that the insertion of the toxin channel could imply the formation in the bilayer of a nonlamellar structure, a toroidal lipid pore. In this case, the presence of lipids favoring a nonlamellar phase, in particular PA and CL, strong inducers of negative curvature in the bilayer, could help in the formation of the pore. This possibility is confirmed by the fact that the formation of toxin pores strongly promotes the rate of transbilayer movement of lipid molecules, which indicates local disruption of the lamellar structure.