Prospective observational cohort study of the association between antiplatelet therapy, bleeding and thrombosis in patients with coronary stents undergoing noncardiac surgery

Background: The perioperative management of antiplatelet therapy in noncardiac surgery patients who have undergone previous percutaneous coronary intervention (PCI) remains a dilemma. Continuing dual antiplatelet therapy (DAPT) may carry a risk of bleeding, while stopping antiplatelet therapy may increase the risk of perioperative major adverse cardiovascular events (MACE). Methods: Occurrence of Bleeding and Thrombosis during Antiplatelet Therapy In Non-Cardiac Surgery (OBTAIN) was an international prospective multicentre cohort study of perioperative antiplatelet treatment, MACE, and serious bleeding in noncardiac surgery. The incidences of MACE and bleeding were compared in patients receiving DAPT, monotherapy, and no antiplatelet therapy before surgery. Unadjusted risk ratios were calculated taking monotherapy as the baseline. The adjusted risks of bleeding and MACE were compared in patients receiving monotherapy and DAPT using propensity score matching. Results: A total of 917 patients were recruited and 847 were eligible for inclusion. Ninety-six patients received no antiplatelet therapy, 526 received monotherapy with aspirin, and 225 received DAPT. Thirty-two patients suffered MACE and 22 had bleeding. The unadjusted risk ratio for MACE in patients receiving DAPT compared with monotherapy was 1.9 (0.93–3.88), P=0.08. There was no difference in MACE between no antiplatelet treatment and monotherapy 1.03 (0.31–3.46), P=0.96. Bleeding was more frequent with DAPT 6.55 (2.3–17.96) P=0.0002. In a propensity matched analysis of 177 patients who received DAPT and 177 monotherapy patients, the risk ratio for MACE with DAPT was 1.83 (0.69–4.85), P=0.32. The risk of bleeding was significantly greater in the DAPT group 4.00 (1.15–13.93), P=0.031. Conclusions: OBTAIN showed an increased risk of bleeding with DAPT and found no evidence for protective effects of DAPT from perioperative MACE in patients who have undergone previous PCI

Adattamento metabolico di calli di actinidia deliciosa in presenza di alte concentrazioni di 3-O-metil glucosio.

Allo scopo di ottenere cellule adattate allo stress osmotico e di analizzare i processi fisiologici e biochimici coinvolti nell'adattamento a tale stress, calli di Actinidia deliciosa sono stati cresciuti per subcolture successive su agar in presenza di 0.2 M 3-0- metilglucosio. (3-0MG). carboidrato non trofico e permeabile le cellule. L' utilizzo di un composto permeabile nasce dalla considerazione che in natura lo stress idrico si verifica in presenza di soluti permeabili e quindi la caduta di turgore dei tessuti non \ue8 cos\uec rapida e drastica come quando viene sperimentalmente imposto utilizzando soluti non permeantile cellule. Il 3-0MG \ue8 assorbito dai calli dove raggiunge in tempi brevi concentrazioni simili a quelle del mezzo. Il potenziale dell' acqua dei calli cresciuti in 3-0MG e soprattutto il potenziale di soluto sono inferiori a quelli del controllo. Nei calli trattati, i livelli di osmoliti quali saccarosio, aminoacidi liberi e K+ sono pi\uf9 elevati, ma tali incrementi non sono tali da giustificare i valori di potenziale di soluto misurati. che quindi sono sostanzialmente dovuti al 3-0MG presente nel tessuto. I livelli di prolina aumentano in modo consistente nelle prime subcolture per poi ridursi e stabilizzarsi nelle ultime. I calli non ossidano il 3- OMG a CO2 tuttavia lo metabolizzano parzialmente. L'esposizione dei calli a 3-0MG determina nella prima subcoltura una caduta del consumo di 02' che poi aumenta sino a raggiungere livelli simili a quelli del controllo. Nei calli trattati una pi\uf9 alta frazione del consumo di O2 \ue8 extramitocondriale; ci\uf2 insieme con un piu basso quoziente respiratorio e pi\uf9 alti livelli di malondialdeide suggerisce l'instaurarsi nel tessuto di condizioni di stress ossidativo. Il tessuto cresciuto in presenza di 3- 0MG ha un contenuto in Ca2+ simile al controllo e un contenuto in Na+ minore. Nei calli di A. deliciosa il K+ \ue8 assorbito attivamente e gli influssi sono pi\uf9 elevati specialmente a basse concentrazioni esterne del catione. I dati nel loro insieme indicano che il trattamento con 3- 0MG induce nel callo classiche risposte adattive a stress osmotici e. dato il carattere particolare dell'agente osmotico utilizzato (\ue8 permeabile), suggeriscono che nelle nostre condizioni tali risposte si innescano non tanto per drastiche e rapide cadute del turgore cellulare ma piuttosto per la condizione di basso potenziale di soluto cellulare determinato dall' elevata concentrazione del 3-0MG nelle cellule. Tali riposte adattative quindi sarebbero correlabili ad effetti chimici o fisici indotti dal 3-0MG stesso. E' inoltre interessante sottolineare come il processo selettivo in esame sembri accompagnarsi a situazioni caratteristiche di stress ossidativo al quale il tessuto potrebbe adattarsi, aumentanto r efficienza dei meccanismi di detossificazione

Effect of Heat Treatment on the Electrochemical and Mechanical Behavior of the Ti6Al4V Alloy

The effects of heat treatment on the hardness and electrochemical behavior of the Ti6Al4V alloy were studied. Two heat treatments were performed: one below (800 °C) and the other above (1050 °C) its beta transformation temperature (T= 980 ± 20 °C) and cooled using three conditions: water quenching, normalizing, and furnace. A microstructure observed using Optical Microscopy showed dependence on the heat treatment temperature applied; mainly three microstructures were obtained: martensitic, globular, and lamellar. Besides, alpha and beta phases were characterized by X-ray diffraction (XRD) technique. The Berkovich tests were performed to measure the hardness and reduced modulus (E). The Ti6Al4V alloy treated at 1050 °C and air-cooled exhibited hardness values closer to those of the Ti6Al4V as-received alloy. Electrochemical tests were carried out to analyze the electrochemical behavior after 7-day immersion in Hank’s solution at 37 °C and pH 7.40. Open Circuit Potentials (E) showed less negative values for Ti6Al4V and Ti6Al4V alloys, suggesting ennoblement of these materials. Furthermore, these alloys exhibited an outstanding electrochemical behavior compared to the Ti6Al4V as-received alloy by Electrochemical Impedance Spectroscopy (EIS) technique.The authors thank David Pérez-Risco for sharing his experience and useful advice on Berkovich Nano-indenter at the National Metallurgical Research Center (CENIM-CSIC Madrid, Spain), allowing this work to be carried out. Mercedes Paulina Chávez-Díaz thanks the National Science and Technology Council (CONACyT) for a doctoral fellowship to hold a research stay at CENIM-CSIC. This work was supported by the Government of Spain, through the Ministry of Economy and Competitiveness [MAT2015-67750-C3-1]. Elsa Miriam Arce-Estrada and Román Cabrera-Sierra wish to thank the National Research System (SNI) for the distinction of its members and the stipend received