Iskanje po repozitoriju

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Objavljeno v DiRROS: 03.04.2024; Ogledov: 98; Prenosov: 28
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Objavljeno v DiRROS: 03.04.2024; Ogledov: 134; Prenosov: 27
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Povzetek: Background. Patient-derived glioblastoma (GBM) stem-like cells (GSCs) represent a valuable model for basic and therapeutic research. GSCs are usually propagated in serum-free Neural Basal medium supplemented with bFGF and EGF. Yet, the exact influence of these growth factors on GSCs is still unclear. Recently it was suggested that GBM stemlike cells with amplified EGFR should be cultured in stem cell medium without EGF, as the presence of EGF induced rapid loss of EGFR amplification. However, patient biopsies are usually taken into culture before their genomic profiles are defined. Thus, an important question remains whether GBM cells without EGFR amplification also can be cultured in stem cell medium without EGF.Meterials and methods. To address this question, we used two heterogeneous glioblastoma GSC lines (NCH421k and NCH644) that lack EGFR amplification.Results. Although both cell lines showed very low EGFR expression under standard growth conditions, bFGF stimulation induced higher expression of EGFR in NCH644. In both cell lines, expression of the stem cell markers nestin and CD133 was higher upon stimulation with bFGF compared to EGF. Importantly, bFGF stimulated the growth of both cell lines, whereas EGF had no effect. We verified that the growth stimulation by bFGF was either mediated by proliferation (NCH421k) or resistance to apoptosis (NCH644).Conclusions. We demonstrate that GSC cultures without EGFR amplification can be maintained and expanded with bFGF, while the addition of EGF has no significant effect and therefore can be omitted.
Ključne besede: glioblastoma, stem cell cultures, bFGF
Objavljeno v DiRROS: 03.04.2024; Ogledov: 96; Prenosov: 37
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Povzetek: Background Hormonal doping in recreational sports is a public-health concern. The World Anti-Doping Agency (WADA) promoted the creation of the Athlete Biological Passport, aiming to monitor athlete’s biological variables over time to facilitate indirect detection of doping. Detection tests for anabolic androgenic steroids (AAS) and growth hormone (GH) are available while insulin abuse cannot be revealed. We have determined in recreational bodybuilders the metabolic effects associated with different patterns of hormone abuse. All analyses were conducted using Statistical Package for Social Sciences (SPSS) 21.0 software (SPSS Chicago, IL). Results We have assessed plasma concentrations of selected metabolic markers and fatty acid content in erythrocyte membranes of 92 male bodybuilders and in 45 healthy controls. Hormonal abuse was identified by anonymous questionnaires. 43% (%) of recruited bodybuilders regularly abused hormones, i.e., anabolic androgenic steroids (95%) often associated with GH (30%) and/or insulin (38%). HDL-cholesterol was lower in insulin and/or GH abusers. Alanine (ALT) and aspartic (AST) transaminases were greater in hormone abusing bodybuilders than in non-doping bodybuilders and controls. Insulin doping was selectively associated with increased plasma ALT-to-AST ratio. In erythrocyte membranes, elongase activity (i.e., stearic-to-palmitic ratio) was lower in insulin and/or growth hormone doping, whereas increased Δ-9 desaturase activity (i.e., palmitoleic-to-palmitic ratio) was selectively associated with insulin doping. Conclusions In conclusion, our study demonstrates that insulin and GH abuse are characterized by multiple alterations of specific metabolic markers. Although further studies are needed to test whether longitudinal monitoring of selected metabolic marker such as muscle contraction time, HDL levels, ALT-AST ratio as well as the activities of selected enzymes (e.g. Δ-9 desaturase and elongase), could contribute to the detection of insulin and GH abuse in sport.
Ključne besede: bodybuilders, doping, drug abuse, matabolism
Objavljeno v DiRROS: 03.04.2024; Ogledov: 90; Prenosov: 43
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Povzetek: The need to reduce energy consumption and the carbon footprint generated by firing ceramics has stimulated research to develop sintering processes carried out at lower temperatures(ideally not above 300 °C) and high pressures (up to 600 MPa), the so-called cold sintering process (CSP) (Grasso et al., 2020, Maria et al., 2017). To evaluate the applicability of CSP to clays, we focused on two representative clay minerals, kaolinite and illite, and on the natural clay material obtained from a Slovenian brick manufacturer. The selected clay materials were characterized on the basis of mineralogical-chemical composition (XRD, XRF) and particle size distribution (SEM analysis, PSD, BET). The powders of clay minerals and natural clay material were first sintered in a heating microscope to determine the sintering conditions and then in a laboratory furnace at 1100 °C for 2 hours and additionally at 1300 °C for kaolinites. The effect of compression of the initial powders on their final properties was also investigated.
Ključne besede: conventional sintering, cold sintering, clay minerals, characterization, mechanical properties
Objavljeno v DiRROS: 29.03.2024; Ogledov: 152; Prenosov: 67
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