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Fertility indices of cows in a high-yielding herd

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The aim of the study was to analyse the effect of non-genetic factors on fertility indices in high-yielding Black-and-White Polish Holstein-Friesian cows. The analysis covered 2414 reproductive periods in 1063 cows born in the years 1999-2008. Fertility indices of the cows were evaluated. The age of heifers at first calving was found to decrease in successive years in the population analysed. A shorter rearing period for heifers was not found to negatively affect fertility indices during their later productive life. A significant decrease in reproductive efficiency was observed in the case of yield exceeding 3600 kg over 100 days of lactation in primiparous cows. However, milk yield in the previous standard lactation had the strongest influence on fertility indices. Where milk yield exceeded 9000 kg, each increase of 2000 kg had a significant (P≤0.01) negative effect on all the fertility indices evaluated in the study.
For many years research on tumour development focused exclusively on the functions of cancer cells. Less attention was paid to tumour-associated cells, which form the tumour microenvironment. Nowadays we know that inflammatory infiltration cells associated with tumour proliferation may have a pro-tumour or an anti-tumour effect. Current studies are focused on interaction (cross-talk) between cells in the tumour microenvironment. Myeloid suppressor cells (MDSCs) and lymphocytes T are special groups of cells associated with tumour. Interaction between cancer cells, MDSCs and lymphocytes T leads to the development of an immunosuppression network that prevents effective combat against cancer cells and creates conditions favourable for tumour progression, migration and metastasis. The understanding of the crosstalk between cancer cells and immune cells has become the main task of scientists and oncologists.
We examined the interaction between the roots of Pinus sylvestris and closely related species Heterobasidion annousum s.l. (H. annosum s.s., H. parviporum, H. abietinum) that differ in host plant preference. The aim of the current study was to determine in roots the accumulation pattern of low molecular mass compounds such as catecholate and hydroxamate derivates, oxalic acid as well as iron-reduction ability of that low molecular mass compounds, that play important roles in wood degradation and they are also involved in pathogenesis. The accumulation of catechol and hydroxamate derivates increased during the early (2–6 h) and late (24–48 h) stages of interaction and similar pattern of oxalic acid accumulation were observed. The level of catecholate derivates in P. sylvestris roots that were challenged with H. parviporum or H. abietinum correlated strongly with iron reducing ability. However, when host was exposed to H. annosum s. s. hydroxamates rather than catecholates regulated iron reducing ability. The extracellular Fe3+ reducing activity was greater for H. annosum s. s. isolates than for isolates of two other species, and reduction of ferric iron may promote oxidative burst in host cell and fungal colonization. Catecholate concentration in the presence of H. annosum s.s. contributing to host cell death, confirm iron involvement in infection success.
Cancer chemotherapy can fail in many ways. One of the most significant is the development of multiple drug resistance (MDR), which constitutes a serious clinical problem. The development of MDR relates to the expression of a major membrane pump, P-glycoprotein (P-gp). Thus, currently one of the goals of experimental and clinical oncology is to decrease its activity. So far, many different P-gp inhibitors are available, but their efficacy is still questionable and requires further study. The aim of our study was to assess an impact of classical P-gp inhibitors (verapamil and cyclosporin A) in the reversion of multidrug resistance in canine mammary cancer cells. We used two cell lines isolated from mammary tumors and two cell lines isolated from their lung metastases. All of them showed P-gp over-expression confirmed using Real-time rt-PCR, Skan^R screening station and confocal microscopy. The FACS analysis showed that in three of the examined cell lines, treatment with verpamil/cyclosporin A was ineffective to reverse cancer chemoresistance. However, more studies in this field are required.
Anthracyclines have commonly been used in the treatment of many cancers in humans and animals for more than two decades. Unfortunately, the cardiotoxicity of these drugs and a mechanism of chemoresistance to anthracyclines are the main factors limiting their use. Drug delivery systems (DDS) are of great promise in cancer therapy because they transport anthracyclines to cancer cells via endocytosis. Drugs transported with delivery systems are also less toxic. The best-studied drug carriers are liposomes, micelles, dendrimers, as well as polymeric and viral nanoparticles. They increase the apoptosis/necrosis of cancer cells, but the drugs are less toxic to normal cells and tissues. Modern drug delivery systems can improve anticancer therapy in humans and in animals.
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