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Objective: Patients suffering from Glioblastoma (GBM) usually present with perilesional edema which is the major contributor of neurologic deficit. Dexamethasone (Dex) has become the corticoid of choice due to its fast and effective alleviation of perilesional edema. The impact of concomitant Dex treatment on TTFields efficacy is unexplored to date. Methods: Human GBM cell lines MZ54 and U251 were treated with TTF in combination with Dex and the effects on cell counts and cell death were determined via flow cytometry. We furthermore investigated the influence of Dex on the cell cycle distribution/cell cycle arrest with and without double thymidine block for synchronisation via flow cytometry in both cell lines. Results: TTF treatment (200 kHz/250 kHz) for 72 h was able to induce massive cell death (70 %) in the cultures of both cell lines. Cell cycle analysis performed after synchronization showed that Dex treatment (65 µM/165 µM) evoked an accumulation of both cell lines in the G0/G1 phase. Concurrent Dex treatment had no significant influence on the extent of apoptosis induced by TTFields. Conclusions: Despite the partial G0/G1 arrest induced by Dex, our results show no interference of Dex with the antitumorous capacity of TTF in vitro. These data support the hypothesis that concomitant therapy with Dex does not negatively interfere with TTF efficacy in primary GBM. Citation Format: Abigail Schiesl, Benedikt Linder, Franz Rödel, Stephanie Hehlgans, Ömer Güllülü, Volker Seifert, Donat Koegel, Christian Senft, Daniel Dubinski. Concomitant dexamethasone treatment and tumor treating fields induced cell death in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1065.

Sažetak Ekološki prihvatljiva maziva su ona, koja će u kontaktu s okolišem uzrokovati minimum štetnog djelovanja, i kod proizvodnje i primjene i kod zbrinjavanja otpada. Jedan od uvjeta ekološke prihvatljivosti je biološka razgradljivost maziva. Pored biološke razgradljivosti potrebna su i ekotoksikološka ispitivanja na bakterije, alge i ribe te određivanje bioakumulacije maziva., Ecologically acceptable lubricants are those that when in contact with the environment cause minimal detrimental effects, both in the process of production and application as well as in the phase of waste disposal. The biodegradability of lubricants is one of the conditions of their ecological acceptability. Along with the biodegradability condition, an ecotoxicological testing on bacterias, sea weeds (algae) and fish is necessary to determine the bioaccumulation of lubricants.

Sažetak Metode za određivanje toksičnosti kemijskih tvari na vodene organizme, propisane organizacijama kao što su OECD, EU ili ISO odnose se na kemijske supstancije s točnim generičkim opisom, tj. propisuju ispitivanje vodotopljivih, kemijski stabilnih i nehlapljivih tvari. Međutim, ako se te metode primjenjuju za tvari koje ne podliježu navedenim svojstvima (tvari koje su samo djelomično ili slabo topljive u vodi, nestabilne, hlapljive ili kompleksnog sastava), mogu se očekivati teškoće u procjeni toksičnosti. Prema sadašnjim saznanjima najbolja raspoloživa metoda za ispitivanje toksičnosti u vodi slabo topljivih kemijskih tvari je WAF metodologija (Water Accommodated Fraction). WAF predstavlja vodeni medij koji sadrži frakciju supstancije zaostale u vodenom mediju nakon miješanja i odvajanja faza. Predmet naših ispitivanja su maziva teško topljiva u vodi od kojih neka imaju svojstvo intenzivnog prijanjanja uz podlogu i maziva ulja koja s vodom stvaraju emulziju. Prema svom sastavu to su maziva na osnovi sintetičkih estera i biljnih ulja različito ugušćeni sa sapunima ili organofilnim bentonitima. Ispitivana maziva miješana su s deioniziranom vodom i mineralnim medijem pomoću elektromagnetske mješalice i u vremenskom razdoblju od 24-96 sati miješanja praćeni su određeni parametri (koncentracija lipofilnih tvari, totalni organski ugljik i prisutnost organskih kiselina eventualno nastalih hidrolizom estera)., Test methods for assessment toxicity chemical substances to aquatic organisms have been described by various organizations including the OECD, EU or ISO. Those test methods are typically designed for substances with precise generic description and substances, which are readily water soluble, chemically stable and non-volatile. When test methods are applied to substances with different chemical properties (sparingly soluble, unstable or volatile substances or those of a complex composition) it is possible to expect some difficulties in toxicity evaluation. According to present knowledge the best test method for toxicity examination of water-resistant substances is WAF methodology (Water Accommodated Fraction). WAF is an aqueous medium containing only that fraction of a substance which remains in the aqueous phase after mixing and phase separation. The subjects for our examination were water-resistant greases (some of them have very strong adhesive characteristics) and lubricant oils which form emulsion with water. According to their chemical composition there are synthetic based esters and plant oils thickned with soaps and organophylic bentonits. The greases were mixed with deionised water and mineral media on magnetic stirrer and during the time period of 24-96 hours some parameters were defined (concentration of lipophylic substances, total organic carbon and organic acids eventually made by ester hydrolyzis).