Preliminary analysis results of LGOM dolomite samples structure modification based on stereological investigations and irreversible strain measurements

W referacie zaprezentowano wyniki wstępnych analiz dotyczących zmian pierwotnej struktury dolomitu z LGOM. Analizy dokonano na podstawie wyników badań stereologicznych naturalnej i naruszonej obciążeniem struktury oraz makroskopowego pomiaru trwałych odkształceń osiowych i poprzecznych rejestrowanych w trakcie testu jednoosiowego ściskania. Uzyskane wyniki badań wyraźnie wskazują na anizotropię zniszczenia tzn. na anizotropowy rozwój spękań w trakcie obciążenia.The results of preliminary analyses of the LGOM dolomite samples concerning on internal structure modifications are presented in this paper. The analyses were based on the stereological investigation of structure modifications of the compressed and uncompressed rock samples and also on the macroscopic measurements of irreversible axial and lateral strains. The results have shown the damage anisotropy i.e. the anisotropy evolution of fractures during loading

Involvement of high-density lipoprotein in stimulatory effect of hormones supporting function of the bovine corpus luteum.

The hypothesis that epinephrine (noradrenaline, NA) enhances utilisation of high-density lipoproteins (HDL) by bovine luteal cells and that this process involves phospholipase (PL) C and protein kinase (PK) C intracellular pathway was tested. Luteal cells from days 2-4, 5-10 or 11-17 of the oestrous cycle were pre-incubated for 20h. Subsequently DMEM/Ham's F-12 medium was replaced by fresh medium and the cells were treated for 6 h as follows: In Experiment I with HDL (5-75μg cholesterol per ml), NA, isoprenaline (ISO) or luteinising hormone (LH). In Experiment II cells were incubated for further 24h in deficient medium (without FCS) and next treated as in Experiment I. In Experiment III cells were stimulated with NA, ISO or LH alone and together with HDL. In Experiment IV cells were treated with PLC inhibitor (U-73122) or with PKC inhibitor (staurosporine) or stimulator (phorbol 12-myristrate 13-acetate) and with either NA, insulin or LH. Only luteal cells from days 5-10 of the cycle responded on HDL and β-mimetics (P<0.05). LH stimulated progesterone secretion from the luteal cells during all stages of the cycle (P<0.001). Cells incubated in deficient medium and supplemented with HDL secreted as much progesterone as those stimulated by LH in all stages of the cycle. Beta-mimetics were unable to enhance the stimulatory effect of HDL. Blockade of PLC had no influence on progesterone secretion from cells treated with either NA or LH, but this did impair the stimulatory effect of insulin (P<0.05). Similarly, blockade of PKC by staurosporine impaired (P<0.05) the effect of insulin only but not that observed after LH or NA treatment. We suggest that: (a) noradrenergic stimulation does not enhance utilisation of cholesterol from HDL for progesterone secretion; (b) the fasting of luteal cells seems to activate enzymes responsible for the progesterone synthesis; (c) effect of NA on progesterone secretion from luteal cells does not involve the PLC-PKC pathway

Dichlorodiphenyldichloroethylene (DDE) residue limit exceeded in pig tissues after feed-borne exposure to maximum allowed concentration

Monitoring of undesirable substances by the European Union indicates a presence of natural and anthropogenic pollutants in animal feed that may be of concern for the producers, as well as the veterinary services. Although the literature concerning toxicity of DDT (an insecticide widely used in the past) is extensive, less attention has been focused on the biological properties of DDE and its interactions with other contaminants. This study reports on the concentration profile of p,p’-DDE and two other ogranochlorines (p,p’-DDT, p,p’-DDD) in different tissues of immature gilts after 14, 28, and 42 days of oral exposure to p,p’-DDE alone (0.5mg·kg-1feed·day-1) and in mixture with naturally occurring mycotoxin zearalenone, ZEN (0.5+0.1mg·kg-1feed·day-1). The treatment resulted in a time-dependent accumulation of p,p’-DDE in fat-rich tissues. Although the pesticide’s concentration found in the adipose tissue exceeded the FAO/WHO maximum residue limit (5mg·kg-1 of fat), human dietary risk is little, as it requires a substantial consumption of such contaminated pork fat. Importantly, the high concentration of p,p’-DDE found in the adrenal glands suggests a threat to the animals’ health. Finally, a difference in the accumulation of p,p’-DDE was observed between the groups treated with this compound alone or in mixture with ZEN. This is most likely related to growth performance of the animals, altered by the endocrine disrupting activity of both compounds. Further research should evaluate the effects of p,p-DDE at the observed concentrations on the pigs’ health status and enable the studies of possible interactions with other environmental pollutants

Dichlorodiphenyldichloroethylene (DDE) residue limit exceeded in pig tissues after feed-borne exposure to maximum allowed concentration

Monitoring of undesirable substances by the European Union indicates a presence of natural and anthropogenic pollutants in animal feed that may be of concern for the producers, as well as the veterinary services. Although the literature concerning toxicity of DDT (an insecticide widely used in the past) is extensive, less attention has been focused on the biological properties of DDE and its interactions with other contaminants. This study reports on the concentration profile of p,p’-DDE and two other ogranochlorines (p,p’-DDT, p,p’-DDD) in different tissues of immature gilts after 14, 28, and 42 days of oral exposure to p,p’-DDE alone (0.5mg·kg-1feed·day-1) and in mixture with naturally occurring mycotoxin zearalenone, ZEN (0.5+0.1mg·kg-1feed·day-1). The treatment resulted in a time-dependent accumulation of p,p’-DDE in fat-rich tissues. Although the pesticide’s concentration found in the adipose tissue exceeded the FAO/WHO maximum residue limit (5mg·kg-1 of fat), human dietary risk is little, as it requires a substantial consumption of such contaminated pork fat. Importantly, the high concentration of p,p’-DDE found in the adrenal glands suggests a threat to the animals’ health. Finally, a difference in the accumulation of p,p’-DDE was observed between the groups treated with this compound alone or in mixture with ZEN. This is most likely related to growth performance of the animals, altered by the endocrine disrupting activity of both compounds. Further research should evaluate the effects of p,p-DDE at the observed concentrations on the pigs’ health status and enable the studies of possible interactions with other environmental pollutants