The in vivo effects of beta-3-receptor agonist CGP-12177 on thyroxine deiodination in cold-exposed, sympathectomized rat brown fat

Objective: The effects of the beta-3-receptor agonist CGP-12177 on thyroxine (T4) deiodination in sympathectomized (SX) interscapular brown adipose tissue (BAT) were assessed in 300 g body weight (BW) Wistar rats. Design: Seven days after SX, groups of rats were implanted s.c. with pellets containing 5 mg CGP-12177 or 5 mg norepinephrine (NE) and were immediately placed at 4°C for 24 h. Other SX groups were injected with CGP-12177 or NE 1 mg/kg BW i.p. and placed in the cold for 4 h. The latter group was injected, in addition, with prazosin 0.4 mg/100 g BW i.p. or propranolol 0.5 mg/100 g BW i.p. 15 min before and 2 h after the administration of CGP-12177 or NE. Methods: Two hours after the last injection of prazosin or propranolol, animals were killed and BAT was removed, homogenized and centrifuged at 500g for 10min at 4°C. The infranatants were incubated during 60min in the presence of dithiothreitol and 1 μCi [125I]T4. Aliquots were chromatographed on paper for the measurement of [125I]T4 and its deiodinated subproducts. Results: CGP-12177 restored normal T4 deiodination in SX BAT from both groups, but NE was slightly more effective. Propranolol, although not prazosin, blocked the CGP-12177 effects. Contrariwise, the NE-induced rise in deiodination was blocked by prazosin and to a lesser extent by propranolol. Conclusions: The results indicate that CGP-12177 stimulated the in vivo activation of 5'-deiodinase type II activity predominantly via beta-3-receptor, without participation of alpha-1-receptors.Fil: Hofer, Dietmar. Karl-Franzens-Universität Graz; AustriaFil: Raices, Marilina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ; ArgentinaFil: Schauenstein, Konrad. Karl-Franzens-Universität Graz; AustriaFil: Porta, Sepp. Karl-Franzens-Universität Graz; AustriaFil: Korsatko, Wolfgang. Karl-Franzens-Universität Graz; AustriaFil: Hagmüller, Karl. Karl-Franzens-Universität Graz; AustriaFil: Zaninovich, Angel Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentin

Određivanje antioksidativne aktivnosti i toksičnosti ekstrakata iz ploda bazge (Sambucus nigra) alternativnim metodama

The aim of the study is to measure the in vitro antioxidant activity of elderberry (Sambucus nigra) fruit extract and to study its toxicity in a plant model system with regard to its possible application in food and agricultural industry. The antioxidant capacity of Sambucus nigra fruit powder was quantified by a photochemiluminescence method. The study of phytotoxicity of aqueous solutions of powder extract was performed using Allium cepa as a test organism. Photochemiluminescence determinations showed a very high antioxidant capacity of the product but also revealed its cytotoxic effect, along with mitodepressive activity and even inhibiton of mitosis at the preprophase stage when the fruit extract was used at higher concentrations. Aqueous solutions of the fruit powder have a reasonably expressed mutagenic activity in vivo on the radicles of Allium cepa, especially when they are used at a concentration of 1 g/dL for a prolonged time (48 h). At lower concentrations (0.1 g/dL), however, the mutagenic effect was not observed any more. The conclusion of our study is that Sambucus nigra fruit extract powder has a very high in vitro antioxidant activity and no mutagenic effects at low concentrations, which makes it recommendable for applications in the food industry.Svrha je ovoga rada bila odrediti in vitro antioksidativnu aktivnost ekstrakta plodova bazge (Sambucus nigra) i njegovu toksičnost za biljke, radi moguće primjene u poljoprivredi i prehrambenoj industriji. Antioksidativna svojstva voćnog praha određena su metodom fotokemiluminiscencije. Ispitana je fitotoksičnost vodene otopine praha ekstrakta bazge na luku (Allium cepa) kao testnom organizmu. Utvrđena je jaka antioksidativna sposobnost proizvoda, ali i njegova citotoksičnost te mitodepresivni učinak. Osim toga, veća koncentracija ekstrakta uzrokovala je inhibiciju mitoze u ranoj profazi. Vodene su otopine voćnog praha imale izrazito mutageni učinak in vivo na korijen luka, osobito duže vrijeme (48 h) pri koncentraciji od 1 g/dL. Pri manjim koncentracijama (0,1 g/dL) nije primijećeno mutageno djelovanje. Može se zaključiti da ekstrakt ploda bazge u prahu ima veliku antioksidativnu aktivnost in vitro, a pri manjim koncentracijama nema mutageni učinak, pa se može primijeniti u prehrambenoj industriji

Determination of Antioxidant Activity and Toxicity of Sambucus nigra Fruit Extract Using Alternative Methods

The aim of the study is to measure the in vitro antioxidant activity of elderberry (Sambucus nigra) fruit extract and to study its toxicity in a plant model system with regard to its possible application in food and agricultural industry. The antioxidant capacity of Sambucus nigra fruit powder was quantified by a photochemiluminescence method. The study of phytotoxicity of aqueous solutions of powder extract was performed using Allium cepa as a test organism. Photochemiluminescence determinations showed a very high antioxidant capacity of the product but also revealed its cytotoxic effect, along with mitodepressive activity and even inhibiton of mitosis at the preprophase stage when the fruit extract was used at higher concentrations. Aqueous solutions of the fruit powder have a reasonably expressed mutagenic activity in vivo on the radicles of Allium cepa, especially when they are used at a concentration of 1 g/dL for a prolonged time (48 h). At lower concentrations (0.1 g/dL), however, the mutagenic effect was not observed any more. The conclusion of our study is that Sambucus nigra fruit extract powder has a very high in vitro antioxidant activity and no mutagenic effects at low concentrations, which makes it recommendable for applications in the food industry

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field