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1.
Artigo em Inglês | MEDLINE | ID: mdl-38753392

RESUMO

Adolescent substance use is linked with negative future outcomes (e.g., depression, anxiety, substance use disorder). Given that the brain undergoes significant maturation during adolescence, this developmental period may represent a time of particular vulnerability to substance use. Neuroimaging research has largely focused on heavy or binge patterns of substance use; thus, relatively less is known about the neural impact of a broader range of adolescent substance use. Characterizing the neural impact of a broader range of adolescent substance use may inform prevention and treatment efforts. The present study investigated relationships between adolescent substance use trajectories (i.e., alcohol, tobacco, and cannabis) and gray matter volume in young adulthood. Substance use was assessed in 1,594 participants at ages 11, 13, 16, and 19. Following the last assessment, 320 participants completed a single magnetic resonance imaging session to assess brain gray matter volume. Latent growth curve models were used to estimate growth parameters characterizing alcohol, tobacco, and cannabis use trajectories for each participant. These growth parameters (i.e., intercept, linear slope, and quadratic slope) were then used as predictors of gray matter volume. The gray matter volume of the hippocampus was positively associated with age 14 alcohol use (i.e., intercept) but not other trajectories (i.e., progression or acceleration) or substances (tobacco or cannabis). These results provide new insight into the neural impact of distinct adolescent alcohol, tobacco, and cannabis use trajectories, which may help to refine prevention and treatment efforts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
J Cell Biol ; 222(7)2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37200023

RESUMO

Endosomal Sorting Complex Required for Transport (ESCRT) proteins can be transiently recruited to the plasma membrane for membrane repair and formation of extracellular vesicles. Here, we discovered micrometer-sized worm-shaped ESCRT structures that stably persist for multiple hours at the plasma membrane of macrophages, dendritic cells, and fibroblasts. These structures surround clusters of integrins and known cargoes of extracellular vesicles. The ESCRT structures are tightly connected to the cellular support and are left behind by the cells together with surrounding patches of membrane. The phospholipid composition is altered at the position of the ESCRT structures, and the actin cytoskeleton is locally degraded, which are hallmarks of membrane damage and extracellular vesicle formation. Disruption of actin polymerization increased the formation of the ESCRT structures and cell adhesion. The ESCRT structures were also present at plasma membrane contact sites with membrane-disrupting silica crystals. We propose that the ESCRT proteins are recruited to adhesion-induced membrane tears to induce extracellular shedding of the damaged membrane.


Assuntos
Actinas , Complexos Endossomais de Distribuição Requeridos para Transporte , Integrinas , Actinas/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Integrinas/genética , Integrinas/metabolismo , Transporte Proteico , Fosfolipídeos/química , Membrana Celular , Macrófagos , Células Dendríticas , Fibroblastos , Humanos , Conformação Proteica
3.
Nat Commun ; 13(1): 6589, 2022 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329028

RESUMO

Receptor Tyrosine Kinase (RTK) endocytosis-dependent signalling drives cell proliferation and motility during development and adult homeostasis, but is dysregulated in diseases, including cancer. The recruitment of RTK signalling partners during endocytosis, specifically during recycling to the plasma membrane, is still unknown. Focusing on Fibroblast Growth Factor Receptor 2b (FGFR2b) recycling, we reveal FGFR signalling partners proximal to recycling endosomes by developing a Spatially Resolved Phosphoproteomics (SRP) approach based on APEX2-driven biotinylation followed by phosphorylated peptides enrichment. Combining this with traditional phosphoproteomics, bioinformatics, and targeted assays, we uncover that FGFR2b stimulated by its recycling ligand FGF10 activates mTOR-dependent signalling and ULK1 at the recycling endosomes, leading to autophagy suppression and cell survival. This adds to the growing importance of RTK recycling in orchestrating cell fate and suggests a therapeutically targetable vulnerability in ligand-responsive cancer cells. Integrating SRP with other systems biology approaches provides a powerful tool to spatially resolve cellular signalling.


Assuntos
Endossomos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Ligantes , Endossomos/metabolismo , Endocitose/fisiologia , Autofagia , Fator 10 de Crescimento de Fibroblastos/metabolismo
4.
Matrix Biol ; 110: 16-39, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35405272

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis due to its aggressive progression, late detection and lack of druggable driver mutations, which often combine to result in unsuitability for surgical intervention. Together with activating mutations of the small GTPase KRas, which are found in over 90% of PDAC tumours, a contributory factor for PDAC tumour progression is formation of a rigid extracellular matrix (ECM) and associated desmoplasia. This response leads to aberrant integrin signalling, and accelerated proliferation and invasion. To identify the integrin adhesion systems that operate in PDAC, we analysed a range of pancreatic ductal epithelial cell models using 2D, 3D and organoid culture systems. Proteomic analysis of isolated integrin receptor complexes from human pancreatic ductal epithelial (HPDE) cells predominantly identified integrin α6ß4 and hemidesmosome components, rather than classical focal adhesion components. Electron microscopy, together with immunofluorescence, confirmed the formation of hemidesmosomes by HPDE cells, both in 2D and 3D culture systems. Similar results were obtained for the human PDAC cell line, SUIT-2. Analysis of HPDE cell secreted proteins and cell-derived matrices (CDM) demonstrated that HPDE cells secrete a range of laminin subunits and form a hemidesmosome-specific, laminin 332-enriched ECM. Expression of mutant KRas (G12V) did not affect hemidesmosome composition or formation by HPDE cells. Cell-ECM contacts formed by mouse and human PDAC organoids were also assessed by electron microscopy. Organoids generated from both the PDAC KPC mouse model and human patient-derived PDAC tissue displayed features of acinar-ductal cell polarity, and hemidesmosomes were visible proximal to prominent basement membranes. Furthermore, electron microscopy identified hemidesmosomes in normal human pancreas. Depletion of integrin ß4 reduced cell proliferation in both SUIT-2 and HPDE cells, reduced the number of SUIT-2 cells in S-phase, and induced G1 cell cycle arrest, suggesting a requirement for α6ß4-mediated adhesion for cell cycle progression and growth. Taken together, these data suggest that laminin-binding adhesion mechanisms in general, and hemidesmosome-mediated adhesion in particular, may be under-appreciated in the context of PDAC. Proteomic data are available via ProteomeXchange with the identifiers PXD027803, PXD027823 and PXD027827.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Animais , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Proliferação de Células , Hemidesmossomos/metabolismo , Humanos , Integrina alfa6beta4/genética , Laminina/metabolismo , Camundongos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Proteômica , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo
5.
Nat Mater ; 21(1): 110-119, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34518665

RESUMO

Experimental in vitro models that capture pathophysiological characteristics of human tumours are essential for basic and translational cancer biology. Here, we describe a fully synthetic hydrogel extracellular matrix designed to elicit key phenotypic traits of the pancreatic environment in culture. To enable the growth of normal and cancerous pancreatic organoids from genetically engineered murine models and human patients, essential adhesive cues were empirically defined and replicated in the hydrogel scaffold, revealing a functional role of laminin-integrin α3/α6 signalling in establishment and survival of pancreatic organoids. Altered tissue stiffness-a hallmark of pancreatic cancer-was recapitulated in culture by adjusting the hydrogel properties to engage mechano-sensing pathways and alter organoid growth. Pancreatic stromal cells were readily incorporated into the hydrogels and replicated phenotypic traits characteristic of the tumour environment in vivo. This model therefore recapitulates a pathologically remodelled tumour microenvironment for studies of normal and pancreatic cancer cells in vitro.


Assuntos
Adenocarcinoma , Neoplasias Pancreáticas , Adenocarcinoma/metabolismo , Animais , Matriz Extracelular , Humanos , Hidrogéis/metabolismo , Camundongos , Organoides , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Microambiente Tumoral
6.
EMBO J ; 40(14): e107182, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34086370

RESUMO

Integration of signalling downstream of individual receptor tyrosine kinases (RTKs) is crucial to fine-tune cellular homeostasis during development and in pathological conditions, including breast cancer. However, how signalling integration is regulated and whether the endocytic fate of single receptors controls such signalling integration remains poorly elucidated. Combining quantitative phosphoproteomics and targeted assays, we generated a detailed picture of recycling-dependent fibroblast growth factor (FGF) signalling in breast cancer cells, with a focus on distinct FGF receptors (FGFRs). We discovered reciprocal priming between FGFRs and epidermal growth factor (EGF) receptor (EGFR) that is coordinated at recycling endosomes. FGFR recycling ligands induce EGFR phosphorylation on threonine 693. This phosphorylation event alters both FGFR and EGFR trafficking and primes FGFR-mediated proliferation but not cell invasion. In turn, FGFR signalling primes EGF-mediated outputs via EGFR threonine 693 phosphorylation. This reciprocal priming between distinct families of RTKs from recycling endosomes exemplifies a novel signalling integration hub where recycling endosomes orchestrate cellular behaviour. Therefore, targeting reciprocal priming over individual receptors may improve personalized therapies in breast and other cancers.


Assuntos
Endossomos/metabolismo , Transporte Proteico/fisiologia , Transdução de Sinais/fisiologia , Tirosina/metabolismo , Linhagem Celular Tumoral , Endocitose/fisiologia , Receptores ErbB/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Humanos , Fosforilação/fisiologia
7.
ACS Catal ; 11(8): 4893-4907, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-34055453

RESUMO

Glycerol solutions were vaporized and reacted over ceria catalysts with different morphologies to investigate the relationship of product distribution to the surface facets exposed, particularly, the yield of bio-renewable methanol. Ceria was prepared with cubic, rodlike, and polyhedral morphologies via hydrothermal synthesis by altering the concentration of the precipitating agent or synthesis temperature. Glycerol conversion was found to be low over the ceria with a cubic morphology, and this was ascribed to both a low surface area and relatively high acidity. Density functional theory calculations also showed that the (100) surface is likely to be hydroxylated under reaction conditions which could limit the availability of basic sites. Methanol space-time-yields over the polyhedral ceria samples were more than four times that for the cubic material at 400 °C, where 201 g of methanol was produced per hour per kilogram of the catalyst. Under comparable glycerol conversions, we show that the rodlike and polyhedral catalysts produce a major intermediate to methanol, hydroxyacetone (HA), with a selectivity of ca. 45%, but that over the cubic sample, this was found to be 15%. This equates to a 13-fold increase in the space-time-yield of HA over the polyhedral samples compared to the cubes at 320 °C. The implications of this difference are discussed with respect to the reaction mechanism, suggesting that a different mechanism dominates over the cubic catalysts to that for rodlike and polyhedral catalysts. The strong association between exposed surface facets of ceria to high methanol yields is an important consideration for future catalyst design in this area.

8.
Aging Cell ; 20(5): e13355, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33830638

RESUMO

Although dysfunctional protein homeostasis (proteostasis) is a key factor in many age-related diseases, the untargeted identification of structurally modified proteins remains challenging. Peptide location fingerprinting is a proteomic analysis technique capable of identifying structural modification-associated differences in mass spectrometry (MS) data sets of complex biological samples. A new webtool (Manchester Peptide Location Fingerprinter), applied to photoaged and intrinsically aged skin proteomes, can relatively quantify peptides and map statistically significant differences to regions within protein structures. New photoageing biomarker candidates were identified in multiple pathways including extracellular matrix organisation (collagens and proteoglycans), protein synthesis and folding (ribosomal proteins and TRiC complex subunits), cornification (keratins) and hemidesmosome assembly (plectin and integrin α6ß4). Crucially, peptide location fingerprinting uniquely identified 120 protein biomarker candidates in the dermis and 71 in the epidermis which were modified as a consequence of photoageing but did not differ significantly in relative abundance (measured by MS1 ion intensity). By applying peptide location fingerprinting to published MS data sets, (identifying biomarker candidates including collagen V and versican in ageing tendon) we demonstrate the potential of the MPLF webtool for biomarker discovery.


Assuntos
Mapeamento de Peptídeos/métodos , Proteômica/métodos , Envelhecimento da Pele , Pele/química , Idoso , Biomarcadores/química , Cromatografia Líquida , Matriz Extracelular/química , Hemidesmossomos/química , Humanos , Queratinas/metabolismo , Pessoa de Meia-Idade , Peptídeos/análise , Biossíntese de Proteínas , Proteoma/química , Envelhecimento da Pele/efeitos da radiação , Software , Espectrometria de Massas em Tandem
10.
Clin Pharmacol Ther ; 109(1): 222-232, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33141922

RESUMO

Variability in individual capacity for hepatic elimination of therapeutic drugs is well recognized and is associated with variable expression and activity of liver enzymes and transporters. Although genotyping offers some degree of stratification, there is often large variability within the same genotype. Direct measurement of protein expression is impractical due to limited access to tissue biopsies. Hence, determination of variability in hepatic drug metabolism and disposition using liquid biopsy (blood samples) is an attractive proposition during drug development and in clinical practice. This study used a multi-"omic" strategy to establish a liquid biopsy technology intended to assess hepatic capacity for metabolism and disposition in individual patients. Plasma exosomal analysis (n = 29) revealed expression of 533 pharmacologically relevant genes at the RNA level, with 147 genes showing evidence of expression at the protein level in matching liver tissue. Correction of exosomal RNA expression using a novel shedding factor improved correlation against liver protein expression for 97 liver-enriched genes. Strong correlation was demonstrated for 12 key drug-metabolizing enzymes and 4 drug transporters. The developed test allowed reliable patient stratification, and in silico trials demonstrated utility in adjusting drug dose to achieve similar drug exposure between patients with variable hepatic elimination. Accordingly, this approach can be applied in characterization of volunteers prior to enrollment in clinical trials and for patient stratification in clinical practice to achieve more precise individual dosing.


Assuntos
Transporte Biológico/fisiologia , Sistema Enzimático do Citocromo P-450/metabolismo , Fígado/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Exossomos/metabolismo , Feminino , Humanos , Inativação Metabólica/fisiologia , Biópsia Líquida/métodos , Masculino , Taxa de Depuração Metabólica/fisiologia , Pessoa de Meia-Idade , Adulto Jovem
11.
Am J Surg ; 219(6): 907-912, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31307660

RESUMO

BACKGROUND: Burnout affects surgical residents' well-being. OBJECTIVE: We sought to identify factors associated with burnout among surgery residents. METHODS: An electronic/anonymous survey was sent to surgical residents at 18 programs, consisting of demographic/programmatic questions and validated scales for burnout, depression, perceived stress, self-efficacy, and social support. Residents were grouped into quartiles based off burnout, and predictors were assessed using univariate and multivariate analyses. RESULTS: 42% of residents surveyed completed it. Burnout was associated with depression, higher perceived stress/debt, fewer weekends off, less programmatic social events, and residents were less likely to reconsider surgery if given the chance. Low burnout was associated with lower depression/stress, higher social support/self-efficacy, more weekends off per month, program mentorship, lower debt, and residents being more likely to choose surgery again if given the chance. On multivariate analysis, higher depression/perceived stress were associated with burnout, and lower burnout scores were associated with lower stress/higher self-efficacy. CONCLUSIONS: Burnout in surgery residents is associated with higher levels of depression and perceived stress. The addition of programmatic social events, limiting weekend work, and formal mentoring programs may decrease burnout.


Assuntos
Atitude Frente a Saúde , Esgotamento Profissional/complicações , Esgotamento Profissional/psicologia , Depressão/complicações , Cirurgia Geral/educação , Internato e Residência , Estresse Ocupacional/complicações , Estresse Ocupacional/psicologia , Autoeficácia , Apoio Social , Adulto , Feminino , Humanos , Masculino
12.
Adv Mater ; 31(4): e1803335, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30488990

RESUMO

The self-assembled layered adsorption of proteins onto nanoparticle (NP) surfaces, once in contact with biological fluids, is termed the "protein corona" and it is gradually seen as a determinant factor for the overall biological behavior of NPs. Here, the previously unreported in vivo protein corona formed in human systemic circulation is described. The human-derived protein corona formed onto PEGylated doxorubicin-encapsulated liposomes (Caelyx) is thoroughly characterized following the recovery of liposomes from the blood circulation of ovarian carcinoma patients. In agreement with previous investigations in mice, the in vivo corona is found to be molecularly richer in comparison to its counterpart ex vivo corona. The intravenously infused liposomes are able to scavenge the blood pool and surface-capture low-molecular-weight, low-abundance plasma proteins that cannot be detected by conventional plasma proteomic analysis. This study describes the previously elusive or postulated formation of protein corona around nanoparticles in vivo in humans and illustrates that it can potentially be used as a novel tool to analyze the blood circulation proteome.


Assuntos
Lipossomos/química , Polietilenoglicóis/química , Coroa de Proteína/química , Adsorção , Doxorrubicina/química , Humanos , Nanopartículas/química
14.
Immunity ; 49(2): 247-263.e7, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-30054205

RESUMO

CD4+ T cell differentiation into multiple T helper (Th) cell lineages is critical for optimal adaptive immune responses. This report identifies an intrinsic mechanism by which programmed death-1 receptor (PD-1) signaling imparted regulatory phenotype to Foxp3+ Th1 cells (denoted as Tbet+iTregPDL1 cells) and inducible regulatory T (iTreg) cells. Tbet+iTregPDL1 cells prevented inflammation in murine models of experimental colitis and experimental graft versus host disease (GvHD). Programmed death ligand-1 (PDL-1) binding to PD-1 imparted regulatory function to Tbet+iTregPDL1 cells and iTreg cells by specifically downregulating endo-lysosomal protease asparaginyl endopeptidase (AEP). AEP regulated Foxp3 stability and blocking AEP imparted regulatory function in Tbet+iTreg cells. Also, Aep-/- iTreg cells significantly inhibited GvHD and maintained Foxp3 expression. PD-1-mediated Foxp3 maintenance in Tbet+ Th1 cells occurred both in tumor infiltrating lymphocytes (TILs) and during chronic viral infection. Collectively, this report has identified an intrinsic function for PD-1 in maintaining Foxp3 through proteolytic pathway.


Assuntos
Cisteína Endopeptidases/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Receptor de Morte Celular Programada 1/metabolismo , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Animais , Diferenciação Celular/imunologia , Células Cultivadas , Colite/imunologia , Colite/patologia , Feminino , Doença Enxerto-Hospedeiro/imunologia , Doença Enxerto-Hospedeiro/patologia , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/patologia , Vírus da Coriomeningite Linfocítica/imunologia , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Linfócitos T Reguladores/citologia , Células Th1/citologia
15.
Methods Mol Biol ; 1636: 235-251, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28730483

RESUMO

Integrin adhesion receptors engage with their extracellular matrix (ECM) ligands, initiating intracellular signaling pathways that regulate a range of fundamental cell functions. Protein kinases and phosphatases play an integral role in integrin adhesion-mediated signaling. However, until recently, knowledge of the phosphorylation sites regulated downstream of integrin ligation was limited to candidate-based approaches and did not support a system-level understanding of the molecular mechanisms through which ECM engagement influences cell behavior. Here, we describe a mass spectrometry (MS)-based phosphoproteomic protocol that enables the global characterization of phosphorylation-based signaling networks activated by integrin-mediated adhesion. To analyze specifically integrin-proximal signaling, the phosphoproteomic workflow involves the affinity-based isolation and analysis of integrin-associated complexes (IACs) rather than proteins solubilized from whole-cell lysates , which are typically used for global phosphoproteomic studies. The detection of phosphorylation sites from IAC proteins was optimized at various stages of the workflow, including IAC isolation, proteolytic digestion, and MS-based data acquisition strategies. The protocol permits the identification and quantification of IAC components by both Western blotting and MS. Notably, compared to phosphoproteomic analyses of cell lysates, the workflow described here enables an improved detection of phosphorylation sites from well-defined IAC proteins, including many known components of the signaling pathways activated by adhesion to the ECM.


Assuntos
Espectrometria de Massas , Fosfoproteínas , Proteoma , Proteômica , Adesão Celular , Linhagem Celular Tumoral , Cromatografia de Afinidade , Cromatografia Líquida , Matriz Extracelular , Humanos , Fosfopeptídeos , Proteômica/métodos , Titânio/química , Fluxo de Trabalho
16.
J Surg Res ; 217: 217-225, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28595817

RESUMO

BACKGROUND: The American Board of Surgery In-Training Examination (ABSITE) is used by programs to evaluate the knowledge and readiness of trainees to sit for the general surgery qualifying examination. It is often used as a tool for resident promotion and may be used by fellowship programs to evaluate candidates. Burnout has been associated with job performance and satisfaction; however, its presence and effects on surgical trainees' performance are not well studied. We sought to understand factors including burnout and study habits that may contribute to performance on the ABSITE examination. METHODS: Anonymous electronic surveys were distributed to all residents at 10 surgical residency programs (n = 326). Questions included demographics as well as study habits, career interests, residency characteristics, and burnout scores using the Oldenburg Burnout Inventory, which assesses burnout because of both exhaustion and disengagement. These surveys were then linked to the individual's 2016 ABSITE and United States Medical Licensing Examination (USMLE) step 1 and 2 scores provided by the programs to determine factors associated with successful ABSITE performance. RESULTS: In total, 48% (n = 157) of the residents completed the survey. Of those completing the survey, 48 (31%) scored in the highest ABSITE quartile (≥75th percentile) and 109 (69%) scored less than the 75th percentile. In univariate analyses, those in the highest ABSITE quartile had significantly higher USMLE step 1 and step 2 scores (P < 0.001), significantly lower burnout scores (disengagement, P < 0.01; exhaustion, P < 0.04), and held opinions that the ABSITE was important for improving their surgical knowledge (P < 0.01). They also read more frequently to prepare for the ABSITE (P < 0.001), had more disciplined study habits (P < 0.001), were more likely to study at the hospital or other public settings (e.g., library, coffee shop compared with at home; P < 0.04), and used active rather than passive study strategies (P < 0.04). Gender, marital status, having children, and debt burden had no correlation with examination success. Backward stepwise multiple regression analysis identified the following independent predictors of ABSITE scores: study location (P < 0.0001), frequency of reading (P = 0.0001), Oldenburg Burnout Inventory exhaustion (P = 0.02), and USMLE step 1 and 2 scores (P = 0.007 and 0.0001, respectively). CONCLUSIONS: Residents who perform higher on the ABSITE have a regular study schedule throughout the year, report less burnout because of exhaustion, study away from home, and have shown success in prior standardized tests. Further study is needed to determine the effects of burnout on clinical duties, career advancement, and satisfaction.


Assuntos
Esgotamento Profissional/psicologia , Avaliação Educacional , Cirurgia Geral/educação , Internato e Residência/estatística & dados numéricos , Habilidades para Realização de Testes/estatística & dados numéricos , Adulto , Feminino , Humanos , Masculino
17.
Chemistry ; 22(35): 12290-4, 2016 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-27392112

RESUMO

We report the direct production of 1,3-butadiene from the dehydration of 2,3-butandiol by using alumina as catalyst. Under optimized kinetic reaction conditions, the production of methyl ethyl ketone and isobutyraldehyde, formed via the pinacol-pinacolone rearrangement, was markedly reduced and almost 80 % selectivity to 1,3-butadiene and 1,3-butadiene could be achieved. The presence of water plays a critical role in the inhibition of oligomerization. The amphoteric nature of γ-Al2 O3 was identified as important and this contributed to the improved catalytic selectivity when compared with other acidic catalysts.

18.
Immunol Lett ; 172: 29-39, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-26905931

RESUMO

Pathogens that induce acute and chronic infections, as well as certain cancers, employ numerous strategies to thwart host cellular and humoral immune defenses. One proposed evasion mechanism against humoral immunity is a localized expression of extracellular proteases that cleave the IgG hinge and disable host IgG functions. Host immunity appears to be prepared to counter such a proteolytic tactic by providing a group of autoantibodies, denoted anti-hinge antibodies that specifically bind to cleaved IgGs and provide compensating functional restoration in vitro. These respective counter-measures highlight the complex interrelationships among pathogens and host immunity and suggested to us a possible means for therapeutic intervention. In this study, we combined an investigation of pathogen-mediated proteolysis of host IgGs with an immunization strategy to boost host anti-hinge antibodies. In a Staphylococcus aureus infection model using an artificial tissue cage (wiffle ball) implanted into rabbits, cleaved rabbit IgGs were detected in abundance in the abscesses of untreated animals early after infection. However, in animals previously immunized with peptide analogs of the cleaved IgG hinge to generate substantial anti-hinge antibody titers, S. aureus colony formation was markedly reduced compared to control animals or those similarly immunized with a scrambled peptide sequence. The results of this study demonstrate that extensive local proteolysis of IgGs occurs in a test abscess setting and that immunization to increase host anti-hinge antibodies provided substantial acute protection against bacterial growth.


Assuntos
Abscesso/imunologia , Imunoglobulina G/imunologia , Fragmentos de Peptídeos/imunologia , Proteínas Recombinantes de Fusão/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Carga Bacteriana , Modelos Animais de Doenças , Combinação de Medicamentos , Adjuvante de Freund/imunologia , Hemocianinas/genética , Humanos , Evasão da Resposta Imune , Imunidade Humoral , Imunização , Imunoglobulina G/genética , Imunoglobulina G/metabolismo , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Extratos Vegetais , Proteólise , Coelhos
19.
Breast Cancer Res ; 18(1): 5, 2016 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-26747277

RESUMO

BACKGROUND: High mammographic density is a therapeutically modifiable risk factor for breast cancer. Although mammographic density is correlated with the relative abundance of collagen-rich fibroglandular tissue, the causative mechanisms, associated structural remodelling and mechanical consequences remain poorly defined. In this study we have developed a new collaborative bedside-to-bench workflow to determine the relationship between mammographic density, collagen abundance and alignment, tissue stiffness and the expression of extracellular matrix organising proteins. METHODS: Mammographic density was assessed in 22 post-menopausal women (aged 54-66 y). A radiologist and a pathologist identified and excised regions of elevated non-cancerous X-ray density prior to laboratory characterization. Collagen abundance was determined by both Masson's trichrome and Picrosirius red staining (which enhances collagen birefringence when viewed under polarised light). The structural specificity of these collagen visualisation methods was determined by comparing the relative birefringence and ultrastructure (visualised by atomic force microscopy) of unaligned collagen I fibrils in reconstituted gels with the highly aligned collagen fibrils in rat tail tendon. Localised collagen fibril organisation and stiffness was also evaluated in tissue sections by atomic force microscopy/spectroscopy and the abundance of key extracellular proteins was assessed using mass spectrometry. RESULTS: Mammographic density was positively correlated with the abundance of aligned periductal fibrils rather than with the abundance of amorphous collagen. Compared with matched tissue resected from the breasts of low mammographic density patients, the highly birefringent tissue in mammographically dense breasts was both significantly stiffer and characterised by large (>80 µm long) fibrillar collagen bundles. Subsequent proteomic analyses not only confirmed the absence of collagen fibrosis in high mammographic density tissue, but additionally identified the up-regulation of periostin and collagen XVI (regulators of collagen fibril structure and architecture) as potential mediators of localised mechanical stiffness. CONCLUSIONS: These preliminary data suggest that remodelling, and hence stiffening, of the existing stromal collagen microarchitecture promotes high mammographic density within the breast. In turn, this aberrant mechanical environment may trigger neoplasia-associated mechanotransduction pathways within the epithelial cell population.


Assuntos
Neoplasias da Mama/genética , Colágeno/metabolismo , Glândulas Mamárias Humanas/anormalidades , Mamografia/métodos , Proteômica , Idoso , Animais , Densidade da Mama , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Moléculas de Adesão Celular/metabolismo , Colágeno/ultraestrutura , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Feminino , Humanos , Microscopia de Força Atômica , Pessoa de Meia-Idade , Ratos , Fatores de Risco
20.
Ophthalmic Epidemiol ; 23(1): 1-5, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26751514

RESUMO

PURPOSE: We present rates of acute primary angle-closure glaucoma (APACG), peripheral iridotomy (PI) and cataract surgery in Scotland between 1998 and 2012. METHODS: The number of patients in Scotland with APACG in each of the years between 1998 and 2012 was obtained from Information Service Division (ISD) Scotland. Data was also obtained for patients who had undergone laser PI and cataract surgery. The annual rates of APACG, PI and cataract surgery were calculated using Scotland's population data during each of these years. RESULTS: Between 1998 and 2012 the rate of APACG in National Health Service patients decreased by 46.4% (from 46.7 to 25.0 per million, p < 0.005). The rate of PI increased overall by 116.3% (from 38.0 to 82.2 per million), but demonstrated a decrease of 48.2% (38.0 to 19.7 per million, p = 0.002) between 1998 and 2008, and an increase of 317.3% (19.7 to 82.2 per million, p = 0.005) between 2008 and 2012. Over the same 15-year period, cataract surgery increased by 73.4% (from 354.2 to 615.2 per 100,000, p < 0.005). In this timeframe, mid-year Scottish population estimates increased by 4.6%. CONCLUSION: Our results demonstrate a significant reduction in the rate of APACG in the Scottish population between 1998 and 2012, along with a rising rate of PI and cataract surgery. The trend of decreasing APACG may be due to the increasing rate of cataract surgery in the same time period. This parallels patterns seen in other European countries. We discuss these findings together with other related epidemiological factors.


Assuntos
Extração de Catarata/tendências , Glaucoma de Ângulo Fechado/epidemiologia , Glaucoma de Ângulo Fechado/cirurgia , Iridectomia/tendências , Iris/cirurgia , Doença Aguda , Adulto , Humanos , Pessoa de Meia-Idade , Escócia/epidemiologia
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