6,461 research outputs found

    Imaging C. elegans Embryos using an Epifluorescent Microscope and Open Source Software

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    Cellular processes, such as chromosome assembly, segregation and cytokinesis,are inherently dynamic. Time-lapse imaging of living cells, using fluorescent-labeled reporter proteins or differential interference contrast (DIC) microscopy, allows for the examination of the temporal progression of these dynamic events which is otherwise inferred from analysis of fixed samples1,2. Moreover, the study of the developmental regulations of cellular processes necessitates conducting time-lapse experiments on an intact organism during development. The Caenorhabiditis elegans embryo is light-transparent and has a rapid, invariant developmental program with a known cell lineage3, thus providing an ideal experiment model for studying questions in cell biology4,5and development6-9. C. elegans is amendable to genetic manipulation by forward genetics (based on random mutagenesis10,11) and reverse genetics to target specific genes (based on RNAi-mediated interference and targeted mutagenesis12-15). In addition, transgenic animals can be readily created to express fluorescently tagged proteins or reporters16,17. These traits combine to make it easy to identify the genetic pathways regulating fundamental cellular and developmental processes in vivo18-21. In this protocol we present methods for live imaging of C. elegans embryos using DIC optics or GFP fluorescence on a compound epifluorescent microscope. We demonstrate the ease with which readily available microscopes, typically used for fixed sample imaging, can also be applied for time-lapse analysis using open-source software to automate the imaging process

    Degradation of the Deubiquitinating Enzyme USP33 is Mediated by p97 and the Ubiquitin Ligase HERC2

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    Because the deubiquitinating enzyme USP33 is involved in several important cellular processes (β-adrenergic receptor recycling, centrosome amplification, RalB signaling, and cancer cell migration), its levels must be carefully regulated. Using quantitative mass spectrometry, we found that the intracellular level of USP33 is highly sensitive to the activity of p97. Knockdown or chemical inhibition of p97 causes robust accumulation of USP33 due to inhibition of its degradation. The p97 adaptor complex involved in this function is the Ufd1-Npl4 heterodimer. Furthermore, we identified HERC2, a HECT-domain-containing E3 ligase, as responsible for polyubiquitination of USP33. Inhibition of p97 causes accumulation of polyubiquitinated USP33, suggesting that p97 is required for post-ubiquitination processing. Thus, our study has identified several key molecules that control USP33 degradation within the ubiquitin-proteasome system

    Survivorship research for people with metastatic or advanced cancer: A time for action

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    Over recent decades, survival outcomes for people diagnosed with cancer have changed dramatically, with approximately 20% improvement in five-year relative survival rates in high-income countries including the United States and Australia. Regardless of regions, there is a decrease in overall cancer mortality rate of about 1% per year. Likewise, the cancer disease trajectory has changed. The traditional linear cancer trajectory in which a patient moves from cancer diagnosis through to a binary outcome (cure or death)—is no longer applicable and does not adequately describe the complexity of experience for many people. Indeed, the availability of targeted therapies and immunotherapies has meant that people diagnosed with cancers once rapidly fatal in the advanced or metastatic stages, such as prostate, breast, ovarian, melanoma, myeloma, and non-small cell lung cancer, are now being treated over relatively long periods of time with treatments that slow the progression of their cancer, prolong life and control cancer symptoms.1 However, despite the ability of these novel therapies to extend life, most patients with an advanced or metastatic cancer diagnosis will never be cured. For these patients, cancer is often a chronic and complex illness that is, often unpredictable and requires ongoing monitoring, treatment, care, and support

    Association between repeat hospitalization and early intervention in dialysis patients following hospital discharge

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    Dialysis patients have a greater number of hospitalization events compared to patients without renal failure. Here we studied the relationship between different post-discharge interventions and repeat hospitalization in over 126,000 prevalent hemodialysis patients to explore outpatient strategies that minimize the risk of repeat hospitalization. The primary outcome was repeat hospitalization within 30 days of discharge. Compared to pre-hospitalization values, the levels of hemoglobin, albumin, phosphorus, calcium, and parathyroid hormone and weight were significantly decreased after hospitalization. Using covariate-adjusted models, those patients whose hemoglobin was monitored within the first 7 days after discharge, followed by modification of their erythropoietin dose had a significantly reduced risk for repeat-hospitalization when compared to the patients whose hemoglobin was not checked, nor was the dose of erythropoietin changed. Similarly, administration of vitamin D within the 7 days following discharge was significantly associated with reduced repeat hospitalization when compared to patients on no vitamin D. Therefore, it appears that immediate re-evaluation of anemia management orders and resumption of vitamin D soon after discharge may be an effective way to reduce repeat hospitalization

    Genome-independent hypoxic repression of estrogen receptor alpha in breast cancer cells

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    Averages and standard deviations of band intensities calculated for all repeats of each western blot in Fig. 2a. Specific band intensities normalized to the loading control bands (β-actin). Calculations derived from at least three independent experiments. (DOCX 17 kb

    Diet and exercise advice and referrals for cancer survivors: An integrative review of medical and nursing perspectives

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    Purpose: To examine the perspectives of medical and nursing health professionals concerning their roles and responsibilities in providing dietary and exercise advice to cancer survivors, and referrals to allied health professionals. Methods: An integrative review. PubMed, CINAHL, PsycINFO, Embase, Web of Science databases, and bibliographies of relevant studies were searched from December 2011 to June 2021. All studies were eligible for inclusion. The Mixed-Methods Appraisal Tool (MMAT) was used to critically appraise included studies. Data were extracted and synthesised regarding the perspectives of medical and nursing health professionals on their roles, responsibilities, barriers, and facilitators. Results: Twenty-one studies involving 3401 medical and nursing health professionals and 264 cancer survivors of diverse cancer types were included. Ten quantitative, nine qualitative, and two mixed-methods studies were eligible. All included studies met at least 80% of the quality criteria in the MMAT. Major findings include the following: (1) medical and nursing health professionals were unclear on their roles in providing dietary and exercise advice to cancer survivors but agreed they play a key role in referrals to dietitians and exercise professionals; (2) most cancer survivors valued the involvement of their general practitioner when receiving dietary and exercise advice. Conclusion: Although medical and nursing health professionals understand that referrals to allied health professionals form part of their role, there is a lack of clarity regarding their roles to provide dietary and exercise advice to cancer survivors. Future studies should address barriers and facilitators of dietary and exercise advice and referral by medical and nursing health professionals

    Transcription Factor Nrf1 Mediates the Proteasome Recovery Pathway after Proteasome Inhibition in Mammalian Cells

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    In Saccharomyces cerevisiae, chemical or genetic inhibition of proteasome activity induces new proteasome synthesis promoted by the transcription factor RPN4. This ensures that proteasome activity is matched to demand. This transcriptional feedback loop is conserved in mammals, but its molecular basis is not understood. Here, we report that nuclear factor erythroid-derived 2-related factor 1 (Nrf1), a transcription factor of the cap “n” collar basic leucine zipper family, but not the related Nrf2, is necessary for induced proteasome gene transcription in mouse embryonic fibroblasts (MEFs). Promoter-reporter assays revealed the importance of antioxidant response elements in Nrf1-mediated upregulation of proteasome subunit genes. Nrf1^(−/−) MEFs were impaired in the recovery of proteasome activity after transient treatment with the covalent proteasome inhibitor YU101, and knockdown of Nrf1 in human cancer cells enhanced cell killing by YU101. Taken together, our results suggest that Nrf1-mediated proteasome homeostasis could be an attractive target for therapeutic intervention in cancer
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