709 research outputs found

    HUWE1 E3 ligase promotes PINK1/PARKINindependent mitophagy by regulating AMBRA1 activation via IKKa

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    The selective removal of undesired or damaged mitochondria by autophagy, known as mitophagy, is crucial for cellular homoeostasis, and prevents tumour diffusion, neurodegeneration and ageing. The pro-autophagic molecule AMBRA1 (autophagy/beclin-1 regulator-1) has been defined as a novel regulator of mitophagy in both PINK1/PARKIN-dependent and -independent systems. Here, we identified the E3 ubiquitin ligase HUWE1 as a key inducing factor in AMBRA1-mediated mitophagy, a process that takes place independently of the main mitophagy receptors. Furthermore, we show that mitophagy function of AMBRA1 is post-translationally controlled, upon HUWE1 activity, by a positive phosphorylation on its serine 1014. This modification is mediated by the IKKα kinase and induces structural changes in AMBRA1, thus promoting its interaction with LC3/GABARAP (mATG8) proteins and its mitophagic activity. Altogether, these results demonstrate that AMBRA1 regulates mitophagy through a novel pathway, in which HUWE1 and IKKα are key factors, shedding new lights on the regulation of mitochondrial quality control and homoeostasis in mammalian cells

    Epidemiology of HIV Infection in Large Urban Areas in the United States

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    Background: While the U.S. HIV epidemic continues to be primarily concentrated in urban area, local epidemiologic profiles may differ and require different approaches in prevention and treatment efforts. We describe the epidemiology of HIV in large urban areas with the highest HIV burden. Methods/Principal Findings: We used data from national HIV surveillance for 12 metropolitan statistical areas (MSAs) to determine disparities in HIV diagnoses and prevalence and changes over time. Overall, 0.3 % to 1 % of the MSA populations were living with HIV at the end of 2007. In each MSA, prevalence was.1 % among blacks; prevalence was.2 % in Miami, New York, and Baltimore. Among Hispanics, prevalence was.1 % in New York and Philadelphia. The relative percentage differences in 2007 HIV diagnosis rates, compared to whites, ranged from 239 (San Francisco) to 1239 (Baltimore) for blacks and from 15 (Miami) to 413 (Philadelphia) for Hispanics. The epidemic remains concentrated, with more than 50 % of HIV diagnoses in 2007 attributed to male-to-male sexual contact in 7 of the 12 MSAs; heterosexual transmission surpassed or equaled male-to-male sexual transmission in Baltimore, Philadelphia, and Washington, DC. Yet in several MSAs, including Baltimore and Washington, DC, AIDS diagnoses increased among men-who-have sex with men in recent years. Conclusions/Significance: These data are useful to identify local drivers of the epidemic and to tailor public health effort

    A mid year comparison study of career satisfaction and emotional states between residents and faculty at one academic medical center

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    BACKGROUND: The Accreditation Council for Graduate Medical Education's (ACGME) new requirements raise multiple challenges for academic medical centers. We sought to evaluate career satisfaction, emotional states, positive and negative experiences, work hours and sleep among residents and faculty simultaneously in one academic medical center after implementation of the ACGME duty hour requirements. METHODS: Residents and faculty (1330) in the academic health center were asked to participate in a confidential survey; 72% of the residents and 66% of the faculty completed the survey. RESULTS: Compared to residents, faculty had higher levels of satisfaction with career choice, competence, importance and usefulness; lower levels of anxiousness and depression. The most positive experiences for both groups corresponded to strong interpersonal relationships and educational value; most negative experiences to poor interpersonal relationships and issues perceived outside of the physician's control. Approximately 13% of the residents and 14% of the faculty were out of compliance with duty hour requirements. Nearly 5% of faculty reported working more than 100 hours per week. For faculty who worked 24 hour shifts, nearly 60% were out of compliance with the duty-hour requirements. CONCLUSION: Reasons for increased satisfaction with career choice, positive emotional states and experiences for faculty compared to residents are unexplained. Earlier studies from this institution identified similar positive findings among advanced residents compared to more junior residents. Faculty are more frequently at risk for duty-hour violations. If patient safety is of prime importance, faculty, in particular, should be compliant with the duty hour requirements. Perhaps the ACGME should contain faculty work hours as part of its regulatory function

    Dental profile of patients with Gaucher disease

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    BACKGROUND: This study was conducted to determine whether patients with Gaucher disease had significant dental pathology because of abnormal bone structure, pancytopenia, and coagulation abnormalities. METHODS: Each patient received a complete oral and periodontal examination in addition to a routine hematological evaluation. RESULTS: Gaucher patients had significantly fewer carious lesions than otherwise healthy carriers. Despite prevalence of anemia, there was no increase in gingival disease; despite the high incidence of thrombocytopenia, gingival bleeding was not noted; and despite radiological evidence of bone involvement, there was no greater incidence loss of teeth or clinical tooth mobility. CONCLUSIONS: These data represent the first survey of the oral health of a large cohort of patients with Gaucher disease. It is a pilot study of a unique population and the results of the investigation are indications for further research. Based on our findings, we recommend regular oral examinations with appropriate dental treatment for patients with Gaucher disease as for other individuals. Consultation between the dentist and physician, preferably one with experience with Gaucher disease, should be considered when surgical procedures are planned

    The Importance of pH in Regulating the Function of the Fasciola hepatica Cathepsin L1 Cysteine Protease

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    The helminth parasite Fasciola hepatica secretes cathepsin L cysteine proteases to invade its host, migrate through tissues and digest haemoglobin, its main source of amino acids. Here we investigated the importance of pH in regulating the activity and functions of the major cathepsin L protease FheCL1. The slightly acidic pH of the parasite gut facilitates the auto-catalytic activation of FheCL1 from its inactive proFheCL1 zymogen; this process was ∼40-fold faster at pH 4.5 than at pH 7.0. Active mature FheCL1 is very stable at acidic and neutral conditions (the enzyme retained ∼45% activity when incubated at 37°C and pH 4.5 for 10 days) and displayed a broad pH range for activity peptide substrates and the protein ovalbumin, peaking between pH 5.5 and pH 7.0. This pH profile likely reflects the need for FheCL1 to function both in the parasite gut and in the host tissues. FheCL1, however, could not cleave its natural substrate Hb in the pH range pH 5.5 and pH 7.0; digestion occurred only at pH≤4.5, which coincided with pH-induced dissociation of the Hb tetramer. Our studies indicate that the acidic pH of the parasite relaxes the Hb structure, making it susceptible to proteolysis by FheCL1. This process is enhanced by glutathione (GSH), the main reducing agent contained in red blood cells. Using mass spectrometry, we show that FheCL1 can degrade Hb to small peptides, predominantly of 4–14 residues, but cannot release free amino acids. Therefore, we suggest that Hb degradation is not completed in the gut lumen but that the resulting peptides are absorbed by the gut epithelial cells for further processing by intracellular di- and amino-peptidases to free amino acids that are distributed through the parasite tissue for protein anabolism

    Effectiveness of accelerated perioperative care and rehabilitation intervention compared to current intervention after hip and knee arthroplasty. A before-after trial of 247 patients with a 3-month follow-up

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    <p>Abstract</p> <p>Background</p> <p>In Denmark, approximately 12,000 hip and knee arthroplasties were performed in 2006, and the hospital costs were close to US$ 110,000,000. In a randomized clinical trial, we have recently demonstrated the efficacy of accelerated perioperative care and rehabilitation intervention after hip and knee arthroplasty compared to current intervention under ideal circumstances. We do not, however, know whether these results could be reached under usual circumstances of healthcare practice. We therefore investigated whether length of stay after implementation of accelerated perioperative care and rehabilitation after hip and knee arthroplasty could be reduced in a normal healthcare setting, and how the achieved results matched those observed during the randomized clinical trial.</p> <p>Methods</p> <p>An effectiveness study as a before-after trial was undertaken in which all elective primary total hip and total knee arthroplasty patients were divided into a before-implementation group receiving the current perioperative procedure, and an after-implementation group receiving the new accelerated perioperative care and rehabilitation procedures as provided by a new multi-disciplinary organization. We used the Breakthrough Series Collaborative Model for implementation. The primary outcome measure was in hospital length of stay (LOS), and the secondary outcome measure was adverse effects within 3 months postoperatively.</p> <p>Results</p> <p>We included a total of 247 patients. Mean LOS was significantly (<it>P </it>< 0.001) reduced by 4.4 (95% CI 3.8–5.0) days after implementation of the accelerated intervention, from 8.8 (SD 3.0) days before implementation to 4.3 (SD 1.8) days after implementation. No significant differences in adverse effects were observed. LOS in this effectiveness study was significantly lower than LOS reported in the efficacy study.</p> <p>Conclusion</p> <p>Accelerated perioperative care and rehabilitation intervention after hip and knee arthroplasty was successfully and effectively implemented. Results obtained during usual hospital circumstances matched the results achieved under ideal circumstances in this group of patients.</p

    Small Heat Shock Protein αA-Crystallin Prevents Photoreceptor Degeneration in Experimental Autoimmune Uveitis

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    The small heat shock protein, αA-crystallin null (αA−/−) mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU). In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB), a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA−/− and wild type mice with EAU as donors and Rag2−/− as the recipient mice), which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ), both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses

    What Lies behind the Wish to Hasten Death? A Systematic Review and Meta-Ethnography from the Perspective of Patients

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    BACKGROUND: There is a need for an in-depth approach to the meaning of the wish to hasten death (WTHD). This study aims to understand the experience of patients with serious or incurable illness who express such a wish. METHODS AND FINDINGS: Systematic review and meta-ethnography of qualitative studies from the patient's perspective. Studies were identified through six databases (ISI, PubMed, PsycINFO, CINAHL, CUIDEN and the Cochrane Register of Controlled Trials), together with citation searches and consultation with experts. Finally, seven studies reporting the experiences of 155 patients were included. The seven-stage Noblit and Hare approach was applied, using reciprocal translation and line-of-argument synthesis. Six main themes emerged giving meaning to the WTHD: WTHD in response to physical/psychological/spiritual suffering, loss of self, fear of dying, the desire to live but not in this way, WTHD as a way of ending suffering, and WTHD as a kind of control over one's life ('having an ace up one's sleeve just in case'). An explanatory model was developed which showed the WTHD to be a reactive phenomenon: a response to multidimensional suffering, rather than only one aspect of the despair that may accompany this suffering. According to this model the factors that lead to the emergence of WTHD are total suffering, loss of self and fear, which together produce an overwhelming emotional distress that generates the WTHD as a way out, i.e. to cease living in this way and to put an end to suffering while maintaining some control over the situation. CONCLUSIONS: The expression of the WTHD in these patients is a response to overwhelming emotional distress and has different meanings, which do not necessarily imply a genuine wish to hasten one's death. These meanings, which have a causal relationship to the phenomenon, should be taken into account when drawing up care plans

    Local deformation in a hydrogel induced by an external magnetic field

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    The aim of this study is to prove the feasibility of a system able to apply local mechanical loading on cells seeded in a hydrogel for tissue engineering applications. This experimental study is based on a previously developed artificial cartilage model with different concentrations of poly(vinyl alcohol) (PVA) that simulates the cartilage extracellular matrix (ECM). Poly(l-lactic acid) (PLLA) microspheres with dispersed magnetic nanoparticles (MNPs) were produced with an emulsion method. These microspheres were embedded in aqueous PVA solutions with varying concentration to resemble increased viscosity of growing tissue during regeneration. The ability to induce a local deformation in the ECM was assessed by applying a steady or an oscillatory magnetic field gradient to different PVA solutions containing the magnetic microparticles, similarly as in ferrogels. PLLA microparticle motion was recorded, and the images were analyzed. Besides, PVA gels and PLLA microparticles were introduced into the pores of a polycaprolactone scaffold, and the microparticle distribution and the mechanical properties of the construct were evaluated. The results of this experimental model show that the dispersion of PLLA microparticles containing MNPs, together with cells in a supporting gel, will allow applying local mechanical stimuli to cells during tissue regeneration. This local stimulation can have a positive effect on the differentiation of seeded cells and improve tissue regeneration.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the MAT2013-46467-C4-1-R project, including the Feder funds. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. 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    NOF1 Encodes an Arabidopsis Protein Involved in the Control of rRNA Expression

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    The control of ribosomal RNA biogenesis is essential for the regulation of protein synthesis in eukaryotic cells. Here, we report the characterization of NOF1 that encodes a putative nucleolar protein involved in the control of rRNA expression in Arabidopsis. The gene has been isolated by T-DNA tagging and its function verified by the characterization of a second allele and genetic complementation of the mutants. The nof1 mutants are affected in female gametogenesis and embryo development. This result is consistent with the detection of NOF1 mRNA in all tissues throughout plant life's cycle, and preferentially in differentiating cells. Interestingly, the closely related proteins from zebra fish and yeast are also necessary for cell division and differentiation. We showed that the nof1-1 mutant displays higher rRNA expression and hypomethylation of rRNA promoter. Taken together, the results presented here demonstrated that NOF1 is an Arabidopsis gene involved in the control of rRNA expression, and suggested that it encodes a putative nucleolar protein, the function of which may be conserved in eukaryotes
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