Indicazioni all\u2019uso delle protesi vascolari per l\u2019accesso emodialitico : un\u2019esperienza italiana basata sul consenso

In Italy, the use of arteriovenous grafts (AVGs) is limited (1-4%) due to different approaches to vascular access management compared to other countries, where guidelines that may not apply to the Italian setting have been produced. Therefore, the Vascular Access Study Group of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. The most controversial and innovative issues of the existing guidelines have been summed up in 12 different topics. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their approval or disapproval on each issue, thus creating a new method to share and exchange information. Almost all agreed on specific criteria for the choice of AVG over native arteriovenous fistulas (AVF) and tunneled venous catheters (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients and patients at risk of developing ischemia, as an alternative to brachiobasilic fistula with vein transposition, and in case of a poorly organized setting. When AVF is feasible, it should be preferred. AVGs are indicated when superficial veins are unavailable or to repair an AVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to allow clinical benefits. The ultimate choice of the graft type is made by the physician in charge of the surgical intervention. Antithrombotic prophylaxis may be justified in some cases

On the Growth of Scientific Knowledge: Yeast Biology as a Case Study

The tempo and mode of human knowledge expansion is an enduring yet poorly understood topic. Through a temporal network analysis of three decades of discoveries of protein interactions and genetic interactions in baker's yeast, we show that the growth of scientific knowledge is exponential over time and that important subjects tend to be studied earlier. However, expansions of different domains of knowledge are highly heterogeneous and episodic such that the temporal turnover of knowledge hubs is much greater than expected by chance. Familiar subjects are preferentially studied over new subjects, leading to a reduced pace of innovation. While research is increasingly done in teams, the number of discoveries per researcher is greater in smaller teams. These findings reveal collective human behaviors in scientific research and help design better strategies in future knowledge exploration

SISTEMA E PROCEDIMENTO DI BONIFICA IN SITU CON ELETTRODI PER LA RIMOZIONE DI INQUINANTI INORGANICI E/O ORGANICI IN UN MEZZO POROSO

Un procedimento di bonifica in situ per la rimozione di inquinanti inorganici e/o organici in un mezzo poroso che utilizza almeno una coppia di elettrodi (E1, E2) per attivare meccanismi di azione in funzione delle condizioni di esercizio. Il procedimento prevede di procedere alla caratterizzazione del sito e all’iniezione nel mezzo poroso di acqua e/o soluzioni chimiche per l’estrazione dal mezzo poroso degli inquinanti presenti e/o la loro degradazione all’interno del mezzo poroso stesso. Per contaminazione da INORGANICI si attivano i processi di mobilizzazione e trasporto al fine di recuperare le specie chimiche in oggetto attraverso pozzi di estrazione (PE) o camere elettrodiche (CE) mediante alimentazione continua (DC). Per contaminazione da ORGANICI si attivano i processi di ossidazione/riduzione e/o biodegradazione e/o elettro-ossidazione/riduzione e/o bio-elettrodegradazione con l’applicazione di alimentazione continua DC e successivamente si attiva una fase di alimentazione alternata AC allo scopo di riscaldare il mezzo poroso per accelerare la cinetica dei processi e/o attivare alcuni ossidanti chimici. Per contaminazione MISTA la sequenza di operazioni può essere individuata sulla base della contaminazione prevalente, dell’abbattimento della contaminazione richiesto e della compatibilità dei differenti meccanismi di azione sulle diverse tipologie di inquinanti

Structural Properties and Dissociative Fluxional Motion of 2,9-Dimethyl-1,10-Phenanthroline in Platinum(II) Complexes

A dynamic H-1 NMR study has been carried out on the fluxional motion of the symmetric chelating ligand 2,9-dimethyl-1,10-phenanthroline(Me-2-phen) between nonequivalent exchanging sites in a variety of square-planar complexes of the type [Pt(Me)(Me-2-phen)(PR3)]BArf, 1-14,(BArf = B[3,5-(CF3)(2)C6H3](4)). In these compounds, the P-donor ligands PR3 encompass a wide range of steric and electronic characteristics [PR3 = P(4-XC6H4)(3), X = H 1, F, 2, Cl 3, CF3 4, MeO 5, Me 6; PR3 = PMe(C6H5)(2) 7, PMe2(C6H5) 8, PMe3 9, PEt3 10,P(i-Pr)(3) 11, PCY(C6H5)(2) 12, PCy2(C6H5) 13, PCy3 14]. All complexes have been synthesized and fully characterized through elemental analysis, H-1 and P-31{H-1} NMR. X-ray crystal structures are reported for the compounds 8, 11, 14, and for Pt(Me)(phen)(P(C6H5)(3))]PF6 (15), all but the last showing loss of planarity and a significant rotation of the Me2-phen moiety around the N1-N2 vector. Steric congestion brought about by the P-donor ligands is responsible for tetrahedral distortion of the coordination plane and significant lengthening of the Pt-N-2 (cis to phosphane) bond distances. Application of standard quantitative analysis of ligand effects (QALE) methodology enabled a quantitative separation of steric and electronic contributions of P-donor ligands to the values of the platinum-phosphorus (1)J(PtP) coupling constants and of the free activation energies DeltaG(double dagger) of the fluxional motion of Me2-phen in 1-14. The steric profiles for both (1)J(PtP) and DeltaG(double dagger) show the onset of steric thresholds (at cone angle values of 150degrees and 148degrees, respectively), that are associated with an overload of steric congestion already evidenced by the crystal structures of 11 and 14. The sharp increase of the fluxional rate of Me-2-phen can be assumed as a perceptive kinetic tool for revealing ground-state destabilization produced by the P-donor ligands. The mechanism involves initial breaking of a metal-nitrogen bond, fast interconversion between two 14-electron three-coordinate T-shaped intermediates containing)eta(1)-coordinated Me-2-phen, and final ring closure. By use of the results from QALE regression analysis, a free-energy surface has been constructed that represents the way in which any single P-donor ligand can affect the energy of the transition state in the absence of aryl or pi-acidity effects

Echocardiographic measurements and cardiac anatomy in healthy Western hognose snakes (Heterodon nasicus)

This study aims to describe the most important cardiac structures in the Heterodon nasicus through echocardiography and anatomical dissection. Echocardiographic and echo-Doppler measurements were performed on twenty healthy adult Heterodon nasicus (10.10). The values of the ventricular length, aortic diameter, pulmonary trunk diameter, the mean thickness of the interventricular septum, and thicknesses of the wall of the cavum pulmonale (Cav. P) and cavum arteriosum (Cav. A), were measured. The aortic flow and pulmonary trunk flow were recorded. Two dead specimens (1.1) were dissected. The male's pulmonary trunk diameter was bigger compared to the female's in both the long and short axis. The reproductive ecology of Heterodon nasicus has yet to be fully elucidated upon, however, male territorialism and dispersal from the hibernacula, and multiple male courtships toward a single female were described, hence, the more active reproductive activity of the male and the consequent sexual selection toward a higher aerobic performance can be hypothesised. A moderate interventricular right to left shunt was noticed in the Cav. V of all the specimens, which is considered normal and should not confuse the clinician. Congenital defects, cardiomyopathies, valvulopathies, and pericardial diseases are known to occur in ophidians and other reptiles. Reliable data and profound knowledge of the anatomy and physiology of the ophidian heart are fundamental for the in vivo diagnosis of cardiac diseases in snakes

Echocardiographic measurements and cardiac anatomy in healthy Western hognose snakes (Heterodon nasicus)

This study aims to describe the most important cardiac structures in the Heterodon nasicus through echocardiography and anatomical dissection. Echocardiographic and echo-Doppler measurements were performed on twenty healthy adult Heterodon nasicus (10.10). The values of the ventricular length, aortic diameter, pulmonary trunk diameter, the mean thickness of the interventricular septum, and thicknesses of the wall of the cavum pul-monale (Cav. P) and cavum arteriosum (Cav. A), were measured. The aortic flow and pulmonary trunk flow were recorded. Two dead specimens (1.1) were dissected. The male's pulmonary trunk diameter was bigger compared to the female's in both the long and short axis. The reproductive ecology of Heterodon nasicus has yet to be fully elucidated upon, however, male territorialism and dispersal from the hibernacula, and multiple male courtships toward a single female were described, hence, the more active reproductive activity of the male and the conse-quent sexual selection toward a higher aerobic performance can be hypothesised. A moderate interventricular right to left shunt was noticed in the Cav. V of all the specimens, which is considered normal and should not confuse the clinician. Congenital defects, cardiomyopathies, valvulopathies, and pericardial diseases are known to occur in ophidians and other reptiles. Reliable data and profound knowledge of the anatomy and physiology of the ophidian heart are fundamental for the in vivo diagnosis of cardiac diseases in snakes

Indications for vascular grafts as hemodialysis access : consensus from experience in Italy

Introduction: In Italy, the use of arteriovenous grafts (AVG) is limited (1-5 %) due to different approaches to vascular access (VA) management as compared to other Countries, where guidelines (which may not apply to the Italian setting) have been produced. Therefore, the Study Group (GdS) on VA of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. Methods: The most controversial and innovative issues of existing guidelines have been summed up in 12 different statements. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their agreement/disagreement on each issue, thus creating a new method to share and exchange information. Results: Most of them agreed (consensus > 90%) on specific criteria set to choose AVG over native AVF (nAVF) and tunnelled venous catheter (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients, in patients at risk of developing ischemia, on the priority of AVG as an alternative to brachial-basilic fistula with vein transposition, and in case of a poorly organized setting regarding graft maintenance. Keeping in mind that the nAVF should be preferred whenever is feasible, AVGs are indicated when superficial veins are unavailable or to repair a nAVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to guarantee its clinical benefits