224 research outputs found

    Peculiarities of educational environment at mining and metallurgical schools of the Urals

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    The relevancy of the issue under study stems from the contradiction between the need for a modern interpretation of the activities of mining and metallurgical schools, which had played a prominent role in the institutionalization of the vocational education environment as well as from moral “obsolescence” of research work results in this field. The goal of the article is the development of environmental indices of mining and metallurgical education of the Urals. The principal concept of research of this problem is the system approach, which allows considering the main peculiarities of the educational environment at mining and metallurgical schools of the Urals comprehensively. This article includes structurally significant characteristics of the educational environment at mining and metallurgical schools of the Urals. The contents of the article may be used for the purpose of modeling, designing and construction of an educational establishment (system) meeting the demands of the new communicational reality within the system of relations between education, industry, and social environment. © 2016 Chapaev, Erofeev and Dvořáková

    A Systematic Literature Review of Students as Partners in Higher Education

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    “Students as Partners” (SaP) in higher education re-envisions students and staff as active collaborators in teaching and learning. Understanding what research on partnership communicates across the literature is timely and relevant as more staff and students come to embrace SaP. Through a systematic literature review of empirical research, we explored the question: How are SaP practices in higher education presented in the academic literature? Trends across results provide insights into four themes: the importance of reciprocity in partnership; the need to make space in the literature for sharing the (equal) realities of partnership; a focus on partnership activities that are small scale, at the undergraduate level, extracurricular, and focused on teaching and learning enhancement; and the need to move toward inclusive, partnered learning communities in higher education. We highlight nine implications for future research and practice.</jats:p

    Proper cytoskeleton α‐tubulin distribution is concomitant to tyrosine phosphorylation during in vitro capacitation and acrosomal reaction in human spermatozoa

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    Spermatozoa motility is a key parameter during the fertilization process. In this context, spermatozoa tyrosine protein phosphorylation and an appropriate cytoskeleton α‐tubulin distribution are some of the most important physiological events involved in motility. However, the relationship between these two biomarkers remains poorly defined. Here, we characterized simultaneously by immunocytochemistry the α‐tubulin (TUBA4A) distribution and the tyrosine phosphorylation at flagellum before capacitation, during different capacitation times (1 and 4 hr), and after acrosome reaction induction in human spermatozoa. We found that the absence of spermatozoa phosphorylation in tyrosine residues positively and significantly correlated (p < 0.05) with the terminal piece α‐tubulin flagellar distribution in all physiological conditions. Conversely, we observed a positive significant correlation (p < 0.01) between phosphorylated spermatozoa and continuous α‐tubulin distribution in spermatozoa flagellum, independently of the physiological condition. Similarly, the subpopulation of spermatozoa with tyrosine phosphorylated and continuous α‐tubulin increases with longer capacitation times and after the acrosome reaction induction. Overall, these findings provide novel insights into the post‐transcriptional physiological events associated to α‐tubulin and the tyrosine phosphorylation during fertilization, which present potential implications for the improvement of spermatozoa selection methods.This research was supported by Human Fertility Cathedra of the University of Alicante, VIOGROB-186, and the project of the Ministry of Economy and Competitiveness AGL2015-70159-P

    The Na+/H+ Exchanger Controls Deoxycholic Acid-Induced Apoptosis by a H+-Activated, Na+-Dependent Ionic Shift in Esophageal Cells

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    Apoptosis resistance is a hallmark of cancer cells. Typically, bile acids induce apoptosis. However during gastrointestinal (GI) tumorigenesis the cancer cells develop resistance to bile acid-induced cell death. To understand how bile acids induce apoptosis resistance we first need to identify the molecular pathways that initiate apoptosis in response to bile acid exposure. In this study we examined the mechanism of deoxycholic acid (DCA)-induced apoptosis, specifically the role of Na+/H+ exchanger (NHE) and Na+ influx in esophageal cells. In vitro studies revealed that the exposure of esophageal cells (JH-EsoAd1, CP-A) to DCA (0.2 mM -0.5 mM) caused lysosomal membrane perturbation and transient cytoplasmic acidification. Fluorescence microscopy in conjunction with atomic absorption spectrophotometry demonstrated that this effect on lysosomes correlated with influx of Na+, subsequent loss of intracellular K+, an increase of Ca2+ and apoptosis. However, ethylisopropyl-amiloride (EIPA), a selective inhibitor of NHE, prevented Na+, K+ and Ca2+ changes and caspase 3/7 activation induced by DCA. Ouabain and amphotericin B, two drugs that increase intracellular Na+ levels, induced similar changes as DCA (ion imbalance, caspase3/7 activation). On the contrary, DCA-induced cell death was inhibited by medium with low a Na+ concentrations. In the same experiments, we exposed rat ileum ex-vivo to DCA with or without EIPA. Severe tissue damage and caspase-3 activation was observed after DCA treatment, but EIPA almost fully prevented this response. In summary, NHE-mediated Na+ influx is a critical step leading to DCA-induced apoptosis. Cells tolerate acidification but evade DCA-induced apoptosis if NHE is inhibited. Our data suggests that suppression of NHE by endogenous or exogenous inhibitors may lead to apoptosis resistance during GI tumorigenesis

    Absence of spermatozoal CD46 protein expression and associated rapid acrosome reaction rate in striped field mice (Apodemus agrarius)

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    <p>Abstract</p> <p>Background</p> <p>In rodents, the cell surface complement regulatory protein CD46 is expressed solely on the spermatozoal acrosome membrane. Ablation of the CD46 gene is associated with a faster acrosome reaction. Sperm from Apodemus flavicollis (yellow-necked field mice), A. microps (pygmy field mice) and A. sylvaticus (European wood mice) fail to express CD46 protein and exhibit a more rapid acrosome reaction rate than Mus (house mice) or BALB/c mice. A. agrarius (striped field mice) belong to a different Apodemus subgenus and have pronounced promiscuity and large relative testis size. The aim of this study was to determine whether A. agrarius sperm fail to express CD46 protein and, if so, whether A. agrarius have a faster acrosome reaction than Mus.</p> <p>Methods</p> <p>Reverse transcription polymerase chain reaction (RT-PCR) was used to assess whether A. agrarius transcribe testicular CD46 mRNA. RT-PCR was supplemented with 3'- and 5'-rapid amplification of cDNA ends to determine the complete nucleotide sequence of A. agrarius CD46. Fluorescence microscopy was used to assess whether CD46 protein is expressed by A. agrarius sperm. The acrosome status of A. agrarius sperm was calculated over time by immunocytochemistry using peanut agglutinin lectin.</p> <p>Results</p> <p>We demonstrate that A. agrarius mice transcribe two unique alternatively spliced testicular CD46 mRNA transcripts, both lacking exon 7, which differ from those described previously in other Apodemus species. The larger A. agrarius CD46 transcript has an insert between exons 10 and 11 which, if translated, would result in a novel cytoplasmic tail. In addition, A. agrarius CD46 transcripts have an extended AU-rich 3'-untranslated region (UTR) and a truncated 5'-UTR, resulting in failure to express spermatozoal CD46 protein. We show that A. agrarius has a significantly faster spontaneous acrosome reaction rate than A. sylvaticus and Mus.</p> <p>Conclusion</p> <p>Absence of CD46 protein expression is associated with acrosomal instability in rodents. A. agrarius mice express novel CD46 transcripts, resulting in the trade of spermatozoal CD46 protein expression for a rapid acrosome reaction rate, in common with other species of field mice. This provides a strategy to increase competitive sperm advantage for individuals, leading to faster fertilisation in this highly promiscuous genus.</p

    Elevated tumour interleukin-1β is associated with systemic inflammation: a marker of reduced survival in gastro-oesophageal cancer

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    Systemic inflammation is associated with adverse prognosis cancer but its aetiology remains unclear. We investigated the expression of proinflammatory cytokines within normal mucosa from healthy controls and tumour tissue in cancer patients and related these levels with markers of systemic inflammation and with the presence of a tumour inflammatory infiltrate. Tissue was collected from 56 patients with gastro-oesophageal cancer and from 12 healthy controls. Tissue cytokine mRNA concentrations were measured by real-time PCR and tissue protein concentrations by cytometric bead array. The degree of chronic inflammatory cell infiltrate was recorded. Serum cytokine and acute phase protein concentrations (including C-reactive protein (CRP)) were measured by enzyme-linked immunosorbent assay. Proinflammatory cytokines were significantly overexpressed (interleukin (IL)-1β, IL-6, IL-8 and tumour necrosis factor-α) both at mRNA and protein levels in the cancer specimens compared with mucosa from controls. Interleukin-1β was expressed in greatest (10–100-fold) concentration and protein levels correlated significantly with systemic inflammation (CRP) (P=0.05, r=0.31). A chronic inflammatory infiltrate was observed in 75% of the cancer specimens and was associated with systemic inflammation (CRP: P=0.01). However, the presence of chronic inflammation per se was not associated with altered cytokine expression within the tumour. Both a chronic inflammatory infiltrate and systemic inflammation (CRP) were associated with reduced survival (P=0.05 and P=0.03, respectively). Tumour chronic inflammatory infiltrate and tumour tissue IL-1β overexpression are potential independent factors influencing systemic inflammation in oesophagogastric cancer patients

    Reactive Oxygen Species Production and Mitochondrial Dysfunction Contribute to Quercetin Induced Death in Leishmania amazonensis

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    BACKGROUND: Leishmaniasis, a parasitic disease caused by protozoa of the genus Leishmania, affects more than 12 million people worldwide. Quercetin has generated considerable interest as a pharmaceutical compound with a wide range of therapeutic activities. One such activity is exhibited against the bloodstream parasite Trypanosoma brucei and amastigotes of Leishmania donovani. However, the mechanism of protozoan action of quercetin has not been studied. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we report here the mechanism for the antileishmanial activity of quercetin against Leishmania amazonensis promastigotes. Quercetin inhibited L. amazonensis promastigote growth in a dose- and time- dependent manner beginning at 48 hours of treatment and with maximum growth inhibition observed at 96 hours. The IC(50) for quercetin at 48 hours was 31.4 µM. Quercetin increased ROS generation in a dose-dependent manner after 48 hours of treatment. The antioxidant GSH and NAC each significantly reduced quercetin-induced cell death. In addition, quercetin caused mitochondrial dysfunction due to collapse of mitochondrial membrane potential. CONCLUSIONS/SIGNIFICANCE: The effects of several drugs that interfere directly with mitochondrial physiology in parasites such as Leishmania have been described. The unique mitochondrial features of Leishmania make this organelle an ideal drug target while minimizing toxicity. Quercetin has been described as a pro-oxidant, generating ROS which are responsible for cell death in some cancer cells. Mitochondrial membrane potential loss can be brought about by ROS added directly in vitro or induced by chemical agents. Taken together, our results demonstrate that quercetin eventually exerts its antileishmanial effect on L. amazonensis promastigotes due to the generation of ROS and disrupted parasite mitochondrial function
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