1071. Environment and breast cancer - the role of xenooestrogens in breast cancerAndrej Plesničar, Branko Družina, Viljem Kovač, Božo Kralj, 2002, original scientific article Abstract: The survival rate of breast cancer patients has not changed much in the last few decades in developed countries. In order to improve the efficacy of breast cancer prevention and treatment, the role of xenooestrogens in the mechanisms of its development has been evaluated. These industrial chemical bear little structural resemblance to each other and bind to the oestrogen receptors of exposed cells and/or trigger oestrogenic responses in laboratory test systems. Exposure to xenooestrogens has been regarded as a risk factor for carcinogenesis and a preventable cause of breast carcinoma. Several epidemiological and experimental studies in in vivo and in vitro conditions of the influence of xenooestrogens on the occurrence of breast cancer have been conducted in the last decades and have shown ambiguous results. No increase of breast carcinoma incidence could be found in women who were exposed to relatively high concentrations of xenooestrogens for extended periods and small quantities of these compounds that are present in the environment probably cannot act as etiological agents for the occurence of this disease. A multi step approach is suggested regarding the sequence of studies and measures that should be taken to further assess the importance of xenooestrogens on breast cancer carcinogenesis.
Keywords: dojka, ksenoestrogeni, novotvorbe
Published in DiRROS: 31.01.2024; Views: 192; Downloads: 48
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1072. Endovascular treatment of intracranial arteriovenous malformationsTomaž Šeruga, 2002, original scientific article Abstract: Background. The aim of the study was the introduction of endovascular treatment of cerebral arteriovenous malformations (AVM) with superselective embolization with polymerisation agent. Case reports. Endovascular embolization was performed in five patients with cerebral AVMs. Three of these patients were presented with intracerebral haemathomas whereas in other two patients, cerebral AVM was an incidental finding. Superselective catheterisation of AVMs was performed and acrylic glue was selectively injected into the nidus. Conclusions. Control cerebral angiography after embolization of AVM showed different results. In one patient, AVM was totally occluded after three sessions and in the second case AVM was occluded in a single session. The rate of occlusion in other two cases was estimated between 70% in 80%. Both of these two patients underwent surgery. One patient is still in the process of treatment. Endovascular treatment of cerebral AVMs with superselective embolization with liquid cyanoacrilyc adhesive agent is a safe and effective alternative treatment paths next to microsurgery. Endovascular tratment in combination with radiosurgery could become the method of choice in the therapy of cerebral AVMs in the future.
Published in DiRROS: 31.01.2024; Views: 200; Downloads: 51
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1074. Fine particulate matter (PM2.5) exposure assessment among active daily commuters to induce behaviour change to reduce air pollutionAnja Ilenič, Alenka Mauko Pranjić, Nina Zupančič, Radmila Milačič, Janez Ščančar, 2023, original scientific article Abstract: Fine particulate matter (PM2.5), a detrimental urban air pollutant primarily emitted by traffic and biomass burning, poses disproportionately significant health risks at relatively limited exposure during commuting. Previous studies have mainly focused on fixed locations when assessing PM2.5 exposure, while neglecting pedestrians and cyclists, who often experience higher pollution levels. In response, this research aimed to independently validate the effectiveness of bicycle-mounted low-cost sensors (LCS) adopted by citizens, evaluate temporal and spatial PM2.5 exposure, and assess associated health risks in Ljubljana, Slovenia. The LCS quality assurance results, verified by co-location field tests by air quality monitoring stations (AQMS), showed comparable outcomes with an average percentage difference of 21.29 %, attributed to humidity-induced nucleation effects. The colder months exhibited the highest air pollution levels (μ = 32.31 μg/m3) due to frequent thermal inversions and weak wind circulation, hindering vertical air mixing and the adequate dispersion of pollutants. Additionally, PM2.5 levels in all sampling periods were lowest in the afternoon (μ = 12.09 μg/m3) and highest during the night (μ = 61.00 μg/m3) when the planetary boundary layer thins, leading to the trapping of pollutants near the surface, thus significantly affecting diurnal and seasonal patterns. Analysis of exposure factors revealed that cyclists were approximately three times more exposed than pedestrians. However, the toxicological risk assessment indicated a minimal potential risk of PM2.5 exposure. The collaborative integration of data from official AQMS and LCS can enhance evidence-based policy-making processes and facilitates the realignment of effective regulatory frameworks to reduce urban air pollution.
Keywords: air pollution monitoring, PM2.5 exposure, citizen science, bicycle-mounted low-cost sensors
Published in DiRROS: 30.01.2024; Views: 302; Downloads: 113
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1078. High-temperature oxidation of boiler steels at 650 °CJaka Burja, Barbara Šetina, Borut Žužek, Tilen Balaško, 2023, original scientific article Abstract: This study presents a comprehensive investigation of the formation, composition and
behaviour of oxide layers during the high-temperature oxidation of four different steel alloys (16Mo3,
13Cr, T24 and P91) at a uniform temperature of 650 °C. The study is aimed at assessing the oxidation
damage due to short-term overheating. The research combines CALPHAD (CALculation of PHAse
Diagrams) calculations, thermogravimetric analysis (TGA) and advanced microscopy techniques, in-
cluding scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), to elucidate
the complex mechanisms controlling oxidation kinetics and oxide layer development. CALPHAD
calculations were used to determine the thermodynamically stable phases for each steel type at 650
◦C and different oxygen activities. The results showed different phase compositions, highlighting
the importance of the chromium content in steel for the formation of oxide layers. The different
oxidation kinetics and oxide layer compositions are presented and associated with the increased risk
of material degradation due to overheating. These results have significant implications for industrial
applications, mainly the susceptibility to oxidation of low-alloyed steels like 16Mo3 and 13 Cr and
contribute to a deeper understanding of oxidation processes in steels.
Keywords: high-temperature oxidation, thermogravimetric analysis, kinetics, CALPHAD, boiler steels, SEM, EBSD
Published in DiRROS: 26.01.2024; Views: 340; Downloads: 148
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1079. Morphological characteristics of young and old murine hematopoietic stem cell niches, as modeled in vitroMojca Justin, Ema Rogac Randl, Veno Kononenko, Matej Hočevar, Damjana Drobne, Primož Rožman, 2023, original scientific article Abstract: The hematopoietic stem cell (HSC) niche undergoes detrimental changes with age. The molecular differences between young and
old niches are well studied and understood; however, young and old niches have not yet been extensively characterized in terms of
morphology. In the present work, a 2D stromal model of young and old HSC niches isolated from bone marrow was investigated
using light and scanning electron microscopy (SEM) to characterize cell density after one, two, or three weeks of culturing, cell
shape, and cell surface morphological features. Our work is aimed at identifying morphological differences between young and
old niche cells that could be used to discriminate between their respective murine HSC niches. The results show several age-
specific morphological characteristics. The old niches differ from the young ones in terms of lower cell proliferating capacity,
increased cell size with a flattened appearance, increased number of adipocytes, and the presence of tunneling nanotubes. In
addition, proliferating cell clusters are present in the young niches but not in the old niches. Together, these characteristics
could be used as a relatively simple and reliable tool to discriminate between young and old murine HSC niches and as a
complementary approach to imaging with specific cellular markers.
Keywords: bone marrow, hematoopetic stem cell niche, aging, adipocytes, scanning electron microscopy
Published in DiRROS: 26.01.2024; Views: 296; Downloads: 132
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