Cambios estacionales de la densidad de peces en una laguna del valle aluvial del rio Parana (Argentina)

En aval du confluent du Parana et du Paraguay, les nombreuses espèces de poissons présentes (dont beaucoup d'intérêt commercial) accomplissent des migrations complexes, latérales et longitudinales, encore inexpliquées. La structure et la densité des communautés de poissons sont fonction, pour chaque endroit, de la période de l'année. Ces variations ont été relevées dans une mare permanente de 274,5 ha dans la zone centrale de la plaine d'inondation (31°42'S; 60°37'W), et reliées à la température et au niveau de l'eau. Des estimations mensuelles de densité ont été faites entre janvier 1982 et janvier 1983 par écho-sondage, ainsi que par des pêches expérimentales utilisant les mêmes filets maillants que ceux des pêcheurs locaux. La prise moyenne a été de 21,5 kg par jour pour 100 m2 de file

Long-term results after modified Burton-Pellegrini’s technique in 24 cases affected by advanced rhizarthrosis

Background and aim: Rhizarthrosis iscommon in elderly and represents 10% of all artrhitic manifestations. Trapeziectomy with ligament reconstruction and tendon interposition remains the gold standard for stages II to IV according to Eaton and Littler. This retrospective study aimed to evaluate the results of 24 patients affected by advanced rhizarthrosis who underwent to modified Burton-Pellegrini’s trapeziectomy with ligamentoplasty using the entire flexor carpi radialis tendon. Methods: Patients were assessed through DASH and PRWHE questionnaires; the examination focused also on pain symptoms (VAS score) and the results obtained in carrying out specific tests to evaluate the trapezius-metacarpal functionality (key-pinch, grip strength, Kapandji test, reduction of wrist flexion strength). Furthermore, postoperative complications were evaluated. Results: Clinical evaluation and individual satisfaction were positive in most cases (mean DASH 18,8 and mean PRWHE 21,7). VAS pain score reduced of 76.7%, grip strength and key pinch were similar to those of the non-operated hand and Kapandji test was excellent in 20 patients. One superficial wound infection was encountered which resolved by specific antibiotic therapy. Conclusions: The choice of the most appropriate treatment depends on clinical conditions and socio-occupational factors of the patient (age, sex and functional needs), the degree of osteoarthritis and the presence of deformities of the first metacarpophalangeal joint. Surgery aims to relief pain and to improve joint function and strength. According to the results observed this surgical technique has to be considered a valid option for the treatment of advanced rhizarthrosis as it provides pain relief, stability and mobility of the thumb. (www.actabiomedica.it)

Systematic review and meta-analysis of fibrin sealants for patients undergoing pancreatic resection

AbstractIntroductionPost-operative pancreatic fistula (POPF) is a common complication after partial pancreatic resection, and is associated with increased rates of sepsis, mortality and costs. The role of fibrin sealants in decreasing the risk of POPF remains debatable. The aim of this study was to evaluate the literature regarding the effectiveness of fibrin sealants in pancreatic surgery.MethodsA comprehensive database search was conducted. Only randomized controlled trials comparing fibrin sealants with standard care were included. A meta-analysis regarding POPF, intra-abdominal collections, post-operative haemorrhage, pancreatitis and wound infections was performed according to the recommendations of the Cochrane collaboration.ResultsSeven studies were included, accounting for 897 patients. Compared with controls, patients receiving fibrin sealants had a pooled odds ratio (OR) of developing a POPF of 0.83 [95% confidence interval (CI): 0.6–1.14], P = 0.245. There was a trend towards a reduction in post-operative haemorrhage (OR = 0.43 (95%CI: 0.18–1.0), P = 0.05) and intra-abdominal collections (OR = 0.52 (95%CI: 0.25–1.06), P = 0.073) in those patients receiving fibrin sealants. No difference was observed in terms of mortality, wound infections, re-interventions or hospital stay.ConclusionOn the basis of these results, fibrin sealants cannot be recommended for routine clinical use in the setting of pancreatic resection

SynaptoPAC, an optogenetic tool for induction of presynaptic plasticity

Optogenetic manipulations have transformed neuroscience in recent years. While sophisticated tools now exist for controlling the firing patterns of neurons, it remains challenging to optogenetically define the plasticity state of individual synapses. A variety of synapses in the mammalian brain express presynaptic long-term potentiation (LTP) upon elevation of presynaptic cyclic adenosine monophosphate (cAMP), but the molecular expression mechanisms as well as the impact of presynaptic LTP on network activity and behavior are not fully understood. In order to establish optogenetic control of presynaptic cAMP levels and thereby presynaptic potentiation, we developed synaptoPAC, a presynaptically targeted version of the photoactivated adenylyl cyclase bPAC. In cultures of hippocampal granule cells, activation of synaptoPAC with blue light increases action potential-evoked transmission, an effect not seen in hippocampal cultures of non-granule cells. In acute brain slices, synaptoPAC activation immediately triggers a strong presynaptic potentiation at mossy fiber terminals in CA3, but not at Schaffer collateral synapse in CA1. Following light-triggered potentiation, mossy fiber transmission decreases within 20 minutes, but remains enhanced still after 30 min. Optogenetic potentiation alters the short-term plasticity dynamics of release, reminiscent of presynaptic LTP. SynaptoPAC is the first optogenetic tool that allows acute light-controlled potentiation of transmitter release at specific synapses of the brain, and will enable to investigate the role of presynaptic potentiation in network function and the animal’s behavior in an unprecedented manner. SIGNIFICANCE STATEMENT: SynaptoPAC is a novel optogenetic tool that allows increasing synaptic transmission by light-controlled induction of presynaptic plasticity

Aquivion® PFSA-based spray-freeze dried composite materials with SiO2 and TiO2 as hybrid catalysts for the gas phase dehydration of ethanol to ethylene in mild conditions

Aquivion PFSA resin, a perfluorinated ion-exchange polymer, has been used as a heterogeneous strong acid catalyst for a range of reactions; however, the activity of this material is limited due to the extremely low surface area of the polymer. In this paper we described the one-step synthesis of Aquivion® PFSA-based hybrid materials using heterocoagulation and spray-freeze-drying of sols containing the precursor of the active phases. The intimated encapsulation of different nano-oxides, such as TiO2 and SiO2 in the superacid resin matrix was easily obtained using this technique and compared with similar catalysts prepared by the impregnation conventional route. The approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution and high surface area. The prepared materials were active and selective for the gas phase dehydration of ethanol to ethylene in mild conditions. The increase of the porosity improved the activity of the composites, compared to the pure Aquivion® PFSA, and allowed to reduce the amount of the superacid resin. Moreover, the type of encapsulated oxide, TiO2 or SiO2, modified the improved performance of the catalysts, having TiO2 the higher efficiency for ethanol conversion and selectivity in ethylene at very low temperature

IRSp53 controls plasma membrane shape and polarized transport at the nascent lumen in epithelial tubules

It is unclear whether the establishment of apical\u2013basal cell polarity during the generation of epithelial lumens requires molecules acting at the plasma membrane/actin interface. Here, we show that the I-BAR-containing IRSp53 protein controls lumen formation and the positioning of the polarity determinants aPKC and podocalyxin. Molecularly, IRSp53 acts by regulating the localization and activity of the small GTPase RAB35, and by interacting with the actin capping protein EPS8. Using correlative light and electron microscopy, we further show that IRSp53 ensures the shape and continuity of the opposing plasma membrane of two daughter cells, leading to the formation of a single apical lumen. Genetic removal of IRSp53 results in abnormal renal tubulogenesis, with altered tubular polarity and architectural organization. Thus, IRSp53 acts as a membrane curvature-sensing platform for the assembly of multi-protein complexes that control the trafficking of apical determinants and the integrity of the luminal plasma membrane

The GTPase-activating protein RN-tre controls focal adhesion turnover and cell migration.

SummaryBackgroundIntegrin-mediated adhesion of cells to the extracellular matrix (ECM) relies on the dynamic formation of focal adhesions (FAs), which are biochemical and mechanosensitive platforms composed of a large variety of cytosolic and transmembrane proteins. During migration, there is a constant turnover of ECM contacts that initially form as nascent adhesions at the leading edge, mature into FAs as actomyosin tension builds up, and are then disassembled at the cell rear, thus allowing for cell detachment. Although the mechanisms of FA assembly have largely been defined, the molecular circuitry that regulates their disassembly still remains elusive.ResultsHere, we show that RN-tre, a GTPase-activating protein (GAP) for Rabs including Rab5 and Rab43, is a novel regulator of FA dynamics and cell migration. RN-tre localizes to FAs and to a pool of Rab5-positive vesicles mainly associated with FAs undergoing rapid remodeling. We found that RN-tre inhibits endocytosis of β1, but not β3, integrins and delays the turnover of FAs, ultimately impairing β1-dependent, but not β3-dependent, chemotactic cell migration. All of these effects are mediated by its GAP activity and rely on Rab5.ConclusionsOur findings identify RN-tre as the Rab5-GAP that spatiotemporally controls FA remodeling during chemotactic cell migration

IRSp53 controls plasma membrane shape and polarized transport at the nascent lumen in epithelial tubules

It is unclear whether the establishment of apical–basal cell polarity during the generation of epithelial lumens requires molecules acting at the plasma membrane/actin interface. Here, we show that the I-BAR-containing IRSp53 protein controls lumen formation and the positioning of the polarity determinants aPKC and podocalyxin. Molecularly, IRSp53 acts by regulating the localization and activity of the small GTPase RAB35, and by interacting with the actin capping protein EPS8. Using correlative light and electron microscopy, we further show that IRSp53 ensures the shape and continuity of the opposing plasma membrane of two daughter cells, leading to the formation of a single apical lumen. Genetic removal of IRSp53 results in abnormal renal tubulogenesis, with altered tubular polarity and architectural organization. Thus, IRSp53 acts as a membrane curvature-sensing platform for the assembly of multi-protein complexes that control the trafficking of apical determinants and the integrity of the luminal plasma membrane

Pre-retrieval reperfusion decreases cancer recurrence after rat ischemic liver graft transplantation

Background & Aims Liver transplantation from marginal donors is associated with ischemia/reperfusion (I/R) lesions, which may increase the risk of post-transplant hepatocellular carcinoma (HCC) recurrence. Graft reperfusion prior to retrieval (as for extracorporeal membrane oxygenation – ECMO) can prevent I/R lesions. The impact of I/R on the risk of cancer recurrence was assessed on a syngeneic Fischer-rat liver transplantation model. Methods HCC cells were injected into the vena porta of all recipients at the end of an orthotopic liver transplantation (OLT). Control donors were standard heart-beating, ischemic ones (ISC), underwent 10min or 30min inflow liver clamping prior to retrieval, and ischemic/reperfused (ISC/R) donors underwent 2h liver reperfusion after the clamping. Results I/R lesions were confirmed in the ISC group, with the presence of endothelial and hepatocyte injury, and increased liver function tests. These lesions were in part reversed by the 2h reperfusion in the ISC/R group. HCC growth was higher in the 10min and 30min ISC recipients ( p =0.018 and 0.004 vs. control, as assessed by MRI difference between weeks one and two), and was prevented in the ISC/Rs ( p =0.04 and 0.01 vs. ISC). These observations were associated with a stronger pro-inflammatory cytokine profile in the ISC recipients only, and the expression of hypoxia and HCC growth-enhancer genes, including Hmox1 , Hif1a and Serpine1 . Conclusions This experiment suggests that ischemia/reperfusion lesions lead to an increased risk of post-transplant HCC recurrence and growth. This observation can be reversed by graft reperfusion prior to retrieval