25 research outputs found
Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy
Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme
Učinak bakra na toksičnost i genotoksičnost kadmija u vodenoj leći (Lemna minor L.)
We investigated interactions between copper (in the concentrations of 2.5 μmol L-1 and 5 μmol L-1) and cadmium (5 μmol L-1) in common duckweed (Lemna minor L.) by exposing it to either metal or to their combinations for four or seven days. Their uptake increased with time, but it was lower in plants treated with combinations of metals than in plants treated with either metal given alone. In separate treatments, either metal increased malondialdehyde (MDA) level and catalase and peroxidase activity. Both induced DNA damage, but copper did it only after 7 days of treatment. On day 4, the combination of cadmium and 5 μmol L-1 copper additionally increased MDA as well as catalase and peroxidase activity. In contrast, on day 7, MDA dropped in plants treated with combinations of metals, and especially with 2.5 μmol L-1 copper plus cadmium. In these plants, catalase activity was higher than in copper treated plants. Peroxidase activity increased after treatment with cadmium and 2.5 μmol L-1 copper but decreased in plants treated with cadmium and 5 μmol L-1 copper. Compared to copper alone, combinations of metals enhanced DNA damage after 4 days of treatment but it dropped on day 7. In conclusion, either metal given alone was toxic/genotoxic and caused oxidative stress. On day 4 of combined treatment, the higher copper concentration was more toxic than either metal alone. In contrast, on day 7 of combined treatment, the lower copper concentration showed lower oxidative and DNA damage. These complex interactions can not be explained by simple antagonism and/or synergism. Further studies should go in that direction.U svrhu istraživanja interakcija između bakra kao esencijalnog elementa te kadmija kao neesencijalnog i toksičnog metala, vodenu leću Lemna minor L. uzgajali smo na podlogama s kadmijem (5 μmol L-1) odnosno s bakrom (2,5 μmol L-1 i 5 μmol L-1) te s njihovim kombinacijama. Unos metala u biljke povećavao se s trajanjem pokusa, a kod kombinacije metala u biljkama je izmjerena niža količina kadmija nego u onima uzgajanima samo na kadmiju. U biljkama tretiranim pojedinačnim metalom došlo je do povećanja
sadržaja malondialdehida (MDA) te aktivnosti katalaze i peroksidaze u odnosu na kontrolne biljke. Također, primijećeno je oštećenje DNA iako kod bakra tek sedmog dana tretmana. Količina MDA i aktivnost obaju enzima dodatno se povećala na tretmanu kombinacijom kadmija i bakra (5 μmol L-1) nakon četvrtog dana pokusa, dok se količina MDA smanjila nakon sedmog dana kod kombinacije kadmija i 2,5 μmol L-1 bakra. U tim biljkama primijećena je i veća aktivnost katalaze, dok je aktivnost peroksidaze porasla na tretmanu kadmijem i 2,5 μmol L-1 bakrom, ali se smanjila na tretmanu kadmijem i 5 μmol L-1 bakrom. Oštećenje DNA koje je bilo veće kod kombinacije metala nakon četvrtog dana, osobito u usporedbi sa samim bakrom, smanjilo se nakon sedmog dana pokusa. Iz ovih rezultata može se zaključiti da su oba metala u istraživanim koncentracijama toksična i genotoksična za vodenu leću i da uzrokuju oksidacijski stres. Kadmij u kombinaciji s bakrom više koncentracije bio je toksičniji od pojedinačnih metala nakon
četvrtog dana pokusa, dok su u biljaka tretiranih kombinacijom kadmija i bakra niže koncentracije toksični učinci bili manji. Budući da su primijećene interakcije vrlo kompleksne i ne uključuju samo antagonizam odnosno sinergizam potrebna su daljnja istraživanja
Green technology meets ecotoxicology
By applying concept and principles of green chemistry into different technological processes, green technologies are developed. The environmental and economic benefits of “green” approach is achieved through several directions, such as the use of renewable raw materials, creation of economic efficiency, the use of alternative reaction conditions, as well as the application of non-conventional solvents. From the point view of green chemistry, alternative solvents, in order to be a “green“ substitution to hazardous organic solvents, should be: non-volatile, non-flammable, stabile, synthesized by an environmentally friendly procedure, nontoxic and biodegradable. The toxic impact of all newly synthesized chemicals, such as alternative solvents, could be determined by methods and techniques of ecotoxicology. Ecotoxicology, an interdisciplinary scientific field, can serve as a way of monitoring the greenness of the processes. In vivo and in vitro experiments are used to study the effects of chemicals on different levels of organizations, from molecules to communities and ecosystem. The usage of in vitro methods is encouraged by a scientific community and regulatory agencies as an alternative to in vivo studies in order to reduce the number of laboratory animals used in the toxicological studies. Therefore, in this paper we gave a brief overview on the usage of animal cell cultures within the field of green chemistry and technology
Dynamics of heat-shock induced DNA damage and repair in senescent tobacco plants
Oxidative stress plays an important role in plant ageing and in response to different stresses. Oxidative DNA damage, unless repaired, may have detrimental consequences and increase genetic instability. Therefore, we determined the role of heat-shock induced oxidative stress on induction and repair of DNA damage in relation to oxidative stress tolerance in senescent tobacco plants. One-month-old (young) and three-month-old (senescent) plants were exposed to 42 °C for 2 and 4 h and left to recover at 26 °C for 24 and 72 h. The progression of senescence was characterized by the lower soluble protein and malondialdehyde content compared to young plants. Immediately after the heat shock, an increase in lipid peroxidation and guaiacol peroxidase activity, as well as DNA damage measured by the Comet assay were induced to higher extent in the young plants than in the senescent ones compared to their respective controls. Moreover, after 24-h recovery, the DNA damage further increased in the young plants whereas tendency of DNA repair was observed in the senescent plants. Upon 72-h recovery, no significant differences were noticed in all parameters studied (regardless of plant age) compared to the controls. The random amplified polymorphic DNA (RAPD) analysis confirmed genetic stability of the tobacco plants during the heat-shock exposures as well as the subsequent recovery periods
Ionske kapljevine – razvoj i izazovi industrijske primjene
Establishment of novel, highly productive, and sustainable processes for the production of industrially important compounds is becoming a growing area of research. Due to non-volatility, inflammability, great thermal, chemical and electrochemical stability and also recyclability, ionic liquids are extensively studied as possible green replacement for widely used conventional molecular solvents. Due to the extremely large number of possible chemical structures of ionic liquids, the ability to design ionic liquids for specific applications makes them unique solvents in electrochemistry, analytical chemistry, organic synthesis and (bio)catalysis, separation processes, as well as functional fluids (lubricants, heat transfer fluids, corrosion inhibitors etc.). This paper presents a review of the scientific and technical literature related to ionic liquids, their basic properties, preparation and application, as well as the challenges of their application on an industrial scale.Uspostavljanje novih visokoučinkovitih i održivih procesa proizvodnje industrijski važnih kemikalija predmet je brojnih znanstvenih istraživanja. Stoga se ionske kapljevine, zbog neznatne hlapljivosti, nezapaljivosti, velike toplinske, kemijske i elektrokemijske stabilnosti, te posebice mogućnosti regeneracije, posljednjih godina intenzivno proučavaju kao zelena zamjena za sveprisutna tradicionalna škodljiva otapala. Budući da je broj mogućih kemijskih struktura ionskih kapljevina iznimno velik, mogućnost dizajniranja ionskih kapljevina za specifične namjene čini ih jedinstvenim otapalima za raznovrsnu uporabu u elekrokemiji, organskoj sintezi i (bio)katalizi, analitici, separacijskim postupcima, ali i kao funkcionalnih kapljevina (sredstva za podmazivanje, akumulatori topline, inhibitori korozije i dr.). U ovom je radu dat pregled znanstvene i stručne literature vezane uz ionske kapljevine, njihova karakteristična svojstva, pripravu i primjenu, ali i izazove njihove primjene u industrijskom mjerilu
Dataset of the vascular e-Learning during the COVID-19 pandemic (EL-COVID) survey
10.1016/j.dib.2021.107442Data in Brief38107442