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1.
Proc Natl Acad Sci U S A ; 117(47): 29720-29729, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-33139533

RESUMO

Forest vulnerability to drought is expected to increase under anthropogenic climate change, and drought-induced mortality and community dynamics following drought have major ecological and societal impacts. Here, we show that tree mortality concomitant with drought has led to short-term (mean 5 y, range 1 to 23 y after mortality) vegetation-type conversion in multiple biomes across the world (131 sites). Self-replacement of the dominant tree species was only prevalent in 21% of the examined cases and forests and woodlands shifted to nonwoody vegetation in 10% of them. The ultimate temporal persistence of such changes remains unknown but, given the key role of biological legacies in long-term ecological succession, this emerging picture of postdrought ecological trajectories highlights the potential for major ecosystem reorganization in the coming decades. Community changes were less pronounced under wetter postmortality conditions. Replacement was also influenced by management intensity, and postdrought shrub dominance was higher when pathogens acted as codrivers of tree mortality. Early change in community composition indicates that forests dominated by mesic species generally shifted toward more xeric communities, with replacing tree and shrub species exhibiting drier bioclimatic optima and distribution ranges. However, shifts toward more mesic communities also occurred and multiple pathways of forest replacement were observed for some species. Drought characteristics, species-specific environmental preferences, plant traits, and ecosystem legacies govern postdrought species turnover and subsequent ecological trajectories, with potential far-reaching implications for forest biodiversity and ecosystem services.


Assuntos
Secas/mortalidade , Florestas , Biodiversidade , Mudança Climática/mortalidade , Ecossistema , Especificidade da Espécie , Árvores/fisiologia
2.
Hepatology ; 72(3): 965-981, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-31875970

RESUMO

BACKGROUND AND AIMS: Intrahepatic cholangiocarcinoma (ICC) is a severe malignant tumor in which the standard therapies are mostly ineffective. The biological significance of the desmoplastic tumor microenvironment (TME) of ICC has been stressed but was insufficiently taken into account in the search for classifications of ICC adapted to clinical trial design. We investigated the heterogeneous tumor stroma composition and built a TME-based classification of ICC tumors that detects potentially targetable ICC subtypes. APPROACH AND RESULTS: We established the bulk gene expression profiles of 78 ICCs. Epithelial and stromal compartments of 23 ICCs were laser microdissected. We quantified 14 gene expression signatures of the TME and those of 3 functional indicators (liver activity, inflammation, immune resistance). The cell population abundances were quantified using the microenvironment cell population-counter package and compared with immunohistochemistry. We performed an unsupervised TME-based classification of 198 ICCs (training set) and 368 ICCs (validation set). We determined immune response and signaling features of the different immune subtypes by functional annotations. We showed that a set of 198 ICCs could be classified into 4 TME-based subtypes related to distinct immune escape mechanisms and patient outcomes. The validity of these immune subtypes was confirmed over an independent set of 368 ICCs and by immunohistochemical analysis of 64 ICC tissue samples. About 45% of ICCs displayed an immune desert phenotype. The other subtypes differed in nature (lymphoid, myeloid, mesenchymal) and abundance of tumor-infiltrating cells. The inflamed subtype (11%) presented a massive T lymphocyte infiltration, an activation of inflammatory and immune checkpoint pathways, and was associated with the longest patient survival. CONCLUSION: We showed the existence of an inflamed ICC subtype, which is potentially treatable with checkpoint blockade immunotherapy.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Imunofenotipagem/métodos , Transdução de Sinais/imunologia , Microambiente Tumoral/imunologia , Neoplasias dos Ductos Biliares/classificação , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/imunologia , Neoplasias dos Ductos Biliares/patologia , Ductos Biliares Intra-Hepáticos/patologia , Colangiocarcinoma/classificação , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/imunologia , Colangiocarcinoma/patologia , Descoberta de Drogas , Feminino , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Imunidade/imunologia , Imuno-Histoquímica , Inflamação/imunologia , Inflamação/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Transcriptoma
3.
Gastroenterology ; 154(4): 1009-1023.e14, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29133078

RESUMO

BACKGROUND & AIMS: Paneth cell dysfunction causes deficiencies in intestinal C-type lectins and antimicrobial peptides, which leads to dysbiosis of the intestinal microbiota, alters the mucosal barrier, and promotes development of inflammatory bowel diseases. We investigated whether transgenic (TG) expression of the human regenerating family member 3 alpha gene (REG3A) alters the fecal microbiota and affects development of colitis in mice. METHODS: We performed studies with C57BL/6 mice that express human regenerating family member 3 alpha (hREG3A) in hepatocytes, via the albumin gene promoter. In these mice, hREG3A travels via the bile to the intestinal lumen. Some mice were given dextran sodium sulfate (DSS) to induce colitis. Feces were collected from mice and the composition of the microbiota was analyzed by 16S ribosomal RNA sequencing. The fecal microbiome was also analyzed from mice that express only 1 copy of human REG3A transgene but were fed feces from control mice (not expressing hREG3A) as newborns. Mice expressing hREG3A were monitored for DSS-induced colitis after cohousing or feeding feces from control mice. Colitis was induced in another set of control and hREG3A-TG mice by administration of trinitrobenzene sulfonic acid; some mice were given intrarectal injections of the hREG3A protein. Colon tissues were collected from mice and analyzed by histology and immunohistochemistry to detect mucin 2, as well as by 16S ribosomal RNA fluorescence in situ hybridization, transcriptional analyses, and quantitative polymerase chain reaction. We measured levels of reactive oxygen species (ROS) in bacterial cultures and fecal microbiota using 2',7'-dichlorofluorescein diacetate and flow cytometry. RESULTS: The fecal microbiota of mice that express hREG3A had a significant shift in composition, compared with control mice, with enrichment of Clostridiales (Ruminococcaceae, Lachnospiraceae) and depletion of Bacteroidetes (Prevotellaceae); the TG mice developed less-severe colitis following administration of DSS than control mice, associated with preserved gut barrier integrity and reduced bacterial translocation, epithelial inflammation, and oxidative damage. A similar shift in the composition of the fecal microbiota occurred after a few months in TG mice heterozygous for REG3A that harbored a wild-type maternal microbiota at birth; these mice developed less-severe forms of colitis following DSS administration. Cohoused and germ-free mice fed feces from REG3A-TG mice and given DSS developed less-severe forms of colitis and had reduced lipopolysaccharide activation of the toll-like receptor 4 and increased survival times compared with mice not fed feces from REG3A-TG mice. REG3A TG mice developed only mild colonic inflammation after exposure to 2,4,6-trinitrobenzene sulfonic acid, compared with control mice. Control mice given intrarectal hREG3A and exposed to 2,4,6-trinitrobenzene sulfonic acid showed less colon damage and inflammation than mice not given intrarectal hREG3A. Fecal samples from REG3A-TG mice had lower levels of ROS than feces from control mice during DSS administration. Addition of hREG3A to bacterial cultures reduced levels of ROS and increased survival of oxygen-sensitive commensal bacteria (Faecalibacterium prausnitzii and Roseburia intestinalis). CONCLUSIONS: Mice with hepatocytes that express hREG3A, which travels to the intestinal lumen, are less sensitive to colitis than control mice. We found hREG3A to alter the colonic microbiota by decreasing levels of ROS. Fecal microbiota from REG3A-TG mice protect non-TG mice from induction of colitis. These findings indicate a role for reduction of oxidative stress in preserving the gut microbiota and its ability to prevent inflammation.


Assuntos
Bactérias/metabolismo , Colite/prevenção & controle , Colo/metabolismo , Microbioma Gastrointestinal , Hepatócitos/metabolismo , Proteínas Associadas a Pancreatite/metabolismo , Animais , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Colite/induzido quimicamente , Colite/metabolismo , Colite/microbiologia , Colo/microbiologia , Sulfato de Dextrana , Modelos Animais de Doenças , Transplante de Microbiota Fecal , Humanos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Viabilidade Microbiana , Estresse Oxidativo/efeitos dos fármacos , Proteínas Associadas a Pancreatite/genética , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo , Ácido Trinitrobenzenossulfônico
4.
J Virol ; 88(9): 5152-64, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24574393

RESUMO

UNLABELLED: The success of future clinical trials with oncolytic viruses depends on the identification and the control of mechanisms that modulate their therapeutic efficacy. In particular, little is known about the role of autophagy in infection by attenuated measles virus of the Edmonston strain (MV-Edm). We investigated the interaction between autophagy, innate immune response, and oncolytic activity of MV-Edm, since the antiviral immune response is a known factor limiting virotherapies. We report that MV-Edm exploits selective autophagy to mitigate the innate immune response mediated by DDX58/RIG-I like receptors (RLRs) in non-small cell lung cancer (NSCLC) cells. Both RNA interference (RNAi) and overexpression approaches demonstrate that autophagy enhances viral replication and inhibits the production of type I interferons regulated by RLRs. We show that MV-Edm unexpectedly triggers SQSTM1/p62-mediated mitophagy, resulting in decreased mitochondrion-tethered mitochondrial antiviral signaling protein (MAVS) and subsequently weakening the innate immune response. These results unveil a novel infectious strategy based on the usurpation of mitophagy leading to mitigation of the innate immune response. This finding provides a rationale to modulate autophagy in oncolytic virotherapy. IMPORTANCE: In vitro studies, preclinical experiments in vivo, and clinical trials with humans all indicate that oncolytic viruses hold promise for cancer therapy. Measles virus of the Edmonston strain (MV-Edm), which is an attenuated virus derived from the common wild-type measles virus, is paradigmatic for therapeutic oncolytic viruses. MV-Edm replicates preferentially in and kills cancer cells. The efficiency of MV-Edm is limited by the immune response of the host against viruses. In our study, we revealed that MV-Edm usurps a homeostatic mechanism of intracellular degradation of mitochondria, coined mitophagy, to attenuate the innate immune response in cancer cells. This strategy might provide a replicative advantage for the virus against the development of antiviral immune responses by the host. These findings are important since they may not only indicate that inducers of autophagy could enhance the efficacy of oncolytic therapies but also provide clues for antiviral therapy by targeting SQSTM1/p62-mediated mitophagy.


Assuntos
RNA Helicases DEAD-box/metabolismo , Vírus do Sarampo/fisiologia , Mitofagia , Vírus Oncolíticos/fisiologia , Transdução de Sinais , Replicação Viral , Linhagem Celular Tumoral , Proteína DEAD-box 58 , Humanos , Imunidade Inata , Vírus do Sarampo/imunologia , Receptores Imunológicos
5.
Glob Chang Biol ; 21(1): 275-86, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25059822

RESUMO

The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network.


Assuntos
Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais/métodos , Ecossistema , Modelos Biológicos , Conservação dos Recursos Naturais/estatística & dados numéricos , Conservação dos Recursos Naturais/tendências
6.
Biomech Model Mechanobiol ; 23(3): 911-925, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38324073

RESUMO

The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin's main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young's modulus, elastic Young's modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young's modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young's modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue.


Assuntos
Colágeno , Derme , Módulo de Elasticidade , Elastina , Estresse Mecânico , Humanos , Elastina/metabolismo , Adulto , Derme/fisiologia , Pessoa de Meia-Idade , Colágeno/metabolismo , Colágeno/química , Fenômenos Biomecânicos , Idoso , Feminino , Masculino , Pele , Adulto Jovem , Imageamento Tridimensional
7.
J Clin Med ; 13(12)2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38930068

RESUMO

Background/Objectives: Severe aortic stenosis (AS) is the most frequent valvular heart disease. Models for stratifying cardiac damage associated with aortic stenosis have been developed to predict outcomes following valve replacement. However, evidence regarding morphological and functional evolution, as well as potential changes in the degree of cardiac damage, is limited. We aim to provide information on the evolution of cardiac morphology and the function of patients undergoing transcatheter aortic valve replacement (TAVR) who have been classified using a cardiac damage staging system. Methods: In total, 496 patients were included in the analysis, and were classified into four stages based on the extent of cardiac damage as follows: Stage 0, no cardiac damage: left ventricle global longitudinal strain (LV-GLS) < -17%; right ventricular-arterial coupling (RVAc) ≥ 0.35), and absence of significant mitral regurgitation (MR). Stage 1, left-sided subclinical damage: LV-GLS ≥ -17%. Stage 2, left-sided damage: significant MR. Stage 3, right-sided damage: RVAc < 0.35. Results: The mean age was 82.1 ± 5.9 years, and 53.0% were female. In total, 24.5% of patients met the criteria for Stage 0, and Stage 1 included 42.8% of patients, Stage 2 included 16.5%, and Stage 3 comprised 16.2% of patients. Mortality was 8.4% for stage 0, 17.4% for stage 1, 25.6% for stage 2, and 28.6% for stage 3 patients (p = 0.004). Diabetes mellitus (DM) (p = 0.047) and chronic kidney disease (CKD) (p = 0.024) were the only clinical predictors of no change or worsening in the stage of cardiac damage. Regarding echocardiographic variables, concomitant tricuspid, and mitral regurgitation, ≥ 2 were both significantly associated with no change or worsening, also (p < 0.001). Conclusions: Cardiac damage that is secondary to severe aortic stenosis has morphological and functional repercussions that, even after valve replacement, persist and might worsen the prognosis.

8.
Anticancer Drugs ; 24(1): 14-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23111416

RESUMO

On the basis of previous findings that certain lung carcinoma cell lines are resistant to the dual PI3K/mTOR inhibitor PI103, we searched for new strategies to overcome this resistance. Here, we report that the lysosomotropic agent chloroquine (CQ) reverses the resistance of lung carcinoma cells to PI3K/mTOR inhibition and primes cells for PI103-induced apoptosis. Investigations of the underlying mechanism of this cooperative interaction show that PI103 increases lysosomal volume and function, as indicated by upregulation of the lysosomal marker protein LAMP-1 and maturation of the lysosomal enzyme cathepsin B, whereas CQ destabilizes lysosomal membranes. Together, CQ and PI103 act in concert to trigger lysosomal membrane permeabilization, resulting in the activation of caspases and apoptosis. The broad-range caspase inhibitor zVAD.fmk significantly decreases PI103-induced and CQ-induced loss of cell viability, indicating that caspases are required for cell death induction. Importantly, inhibition of lysosomal enzymes by CA-074me significantly reduces PI103-mediated and CQ-mediated loss of cell viability, showing that lysosomal enzymes are critical mediators of PI103/CQ-induced cytotoxicity. In conclusion, CQ overcomes resistance of lung carcinoma cells to PI103-induced apoptosis by cooperating with PI103 to trigger lysosome-mediated apoptosis. These findings have important implications for developing effective PI3K/mTOR inhibitor-based therapies for lung cancer.


Assuntos
Antineoplásicos/farmacologia , Cloroquina/farmacologia , Furanos/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Piridinas/farmacologia , Pirimidinas/farmacologia , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Catepsina B/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Furanos/administração & dosagem , Humanos , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Neoplasias Pulmonares/patologia , Proteína 1 de Membrana Associada ao Lisossomo/genética , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Permeabilidade , Inibidores de Fosfoinositídeo-3 Quinase , Piridinas/administração & dosagem , Pirimidinas/administração & dosagem , Serina-Treonina Quinases TOR/antagonistas & inibidores , Regulação para Cima/efeitos dos fármacos
9.
Radiat Oncol ; 18(1): 91, 2023 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-37248490

RESUMO

BACKGROUND: Segmentation of the Gross Tumor Volume (GTV) is a crucial step in the brachytherapy (BT) treatment planning workflow. Currently, radiation oncologists segment the GTV manually, which is time-consuming. The time pressure is particularly critical for BT because during the segmentation process the patient waits immobilized in bed with the applicator in place. Automatic segmentation algorithms can potentially reduce both the clinical workload and the patient burden. Although deep learning based automatic segmentation algorithms have been extensively developed for organs at risk, automatic segmentation of the targets is less common. The aim of this study was to automatically segment the cervical cancer GTV on BT MRI images using a state-of-the-art automatic segmentation framework and assess its performance. METHODS: A cohort of 195 cervical cancer patients treated between August 2012 and December 2021 was retrospectively collected. A total of 524 separate BT fractions were included and the axial T2-weighted (T2w) MRI sequence was used for this project. The 3D nnU-Net was used as the automatic segmentation framework. The automatic segmentations were compared with the manual segmentations used for clinical practice with Sørensen-Dice coefficient (Dice), 95th Hausdorff distance (95th HD) and mean surface distance (MSD). The dosimetric impact was defined as the difference in D98 (ΔD98) and D90 (ΔD90) between the manual segmentations and the automatic segmentations, evaluated using the clinical dose distribution. The performance of the network was also compared separately depending on FIGO stage and on GTV volume. RESULTS: The network achieved a median Dice of 0.73 (interquartile range (IQR) = 0.50-0.80), median 95th HD of 6.8 mm (IQR = 4.2-12.5 mm) and median MSD of 1.4 mm (IQR = 0.90-2.8 mm). The median ΔD90 and ΔD98 were 0.18 Gy (IQR = -1.38-1.19 Gy) and 0.20 Gy (IQR =-1.10-0.95 Gy) respectively. No significant differences in geometric or dosimetric performance were observed between tumors with different FIGO stages, however significantly improved Dice and dosimetric performance was found for larger tumors. CONCLUSIONS: The nnU-Net framework achieved state-of-the-art performance in the segmentation of the cervical cancer GTV on BT MRI images. Reasonable median performance was achieved geometrically and dosimetrically but with high variability among patients.


Assuntos
Braquiterapia , Aprendizado Profundo , Neoplasias do Colo do Útero , Feminino , Humanos , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/radioterapia , Neoplasias do Colo do Útero/patologia , Braquiterapia/métodos , Carga Tumoral , Estudos Retrospectivos , Imageamento por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador
10.
Phys Imaging Radiat Oncol ; 28: 100500, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37869474

RESUMO

Background and purpose: Existing methods for quality assurance of the radiotherapy auto-segmentations focus on the correlation between the average model entropy and the Dice Similarity Coefficient (DSC) only. We identified a metric directly derived from the output of the network and correlated it with clinically relevant metrics for contour accuracy. Materials and Methods: Magnetic Resonance Imaging auto-segmentations were available for the gross tumor volume for cervical cancer brachytherapy (106 segmentations) and for the clinical target volume for rectal cancer external-beam radiotherapy (77 segmentations). The nnU-Net's output before binarization was taken as a score map. We defined a metric as the mean of the voxels in the score map above a threshold (λ). Comparisons were made with the mean and standard deviation over the score map and with the mean over the entropy map. The DSC, the 95th Hausdorff distance, the mean surface distance (MSD) and the surface DSC were computed for segmentation quality. Correlations between the studied metrics and model quality were assessed with the Pearson correlation coefficient (r). The area under the curve (AUC) was determined for detecting segmentations that require reviewing. Results: For both tasks, our metric (λ = 0.30) correlated more strongly with the segmentation quality than the mean over the entropy map (for surface DSC, r > 0.65 vs. r < 0.60). The AUC was above 0.84 for detecting MSD values above 2 mm. Conclusions: Our metric correlated strongly with clinically relevant segmentation metrics and detected segmentations that required reviewing, indicating its potential for automatic quality assurance of radiotherapy target auto-segmentations.

11.
Commun Biol ; 6(1): 269, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36918710

RESUMO

Innate immune mediators of pathogen clearance, including the secreted C-type lectins REG3 of the antimicrobial peptide (AMP) family, are known to be involved in the regulation of tissue repair and homeostasis. Their role in metabolic homeostasis remains unknown. Here we show that an increase in human REG3A improves glucose and lipid homeostasis in nutritional and genetic mouse models of obesity and type 2 diabetes. Mice overexpressing REG3A in the liver show improved glucose homeostasis, which is reflected in better insulin sensitivity in normal weight and obese states. Delivery of recombinant REG3A protein to leptin-deficient ob/ob mice or wild-type mice on a high-fat diet also improves glucose homeostasis. This is accompanied by reduced oxidative protein damage, increased AMPK phosphorylation and insulin-stimulated glucose uptake in skeletal muscle tissue. Oxidative damage in differentiated C2C12 myotubes is greatly attenuated by REG3A, as is the increase in gp130-mediated AMPK activation. In contrast, Akt-mediated insulin action, which is impaired by oxidative stress, is not restored by REG3A. These data highlight the importance of REG3A in controlling oxidative protein damage involved in energy and metabolic pathways during obesity and diabetes, and provide additional insight into the dual function of host-immune defense and metabolic regulation for AMP.


Assuntos
Anti-Infecciosos , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Resistência à Insulina , Camundongos , Humanos , Animais , Camundongos Obesos , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Experimental/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Glucose/metabolismo , Obesidade/genética , Insulina/farmacologia , Homeostase , Anti-Infecciosos/farmacologia
12.
Proc Natl Acad Sci U S A ; 106(24): 9721-4, 2009 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-19509337

RESUMO

Managed relocation (MR) has rapidly emerged as a potential intervention strategy in the toolbox of biodiversity management under climate change. Previous authors have suggested that MR (also referred to as assisted colonization, assisted migration, or assisted translocation) could be a last-alternative option after interrogating a linear decision tree. We argue that numerous interacting and value-laden considerations demand a more inclusive strategy for evaluating MR. The pace of modern climate change demands decision making with imperfect information, and tools that elucidate this uncertainty and integrate scientific information and social values are urgently needed. We present a heuristic tool that incorporates both ecological and social criteria in a multidimensional decision-making framework. For visualization purposes, we collapse these criteria into 4 classes that can be depicted in graphical 2-D space. This framework offers a pragmatic approach for summarizing key dimensions of MR: capturing uncertainty in the evaluation criteria, creating transparency in the evaluation process, and recognizing the inherent tradeoffs that different stakeholders bring to evaluation of MR and its alternatives.


Assuntos
Biodiversidade , Animais , Incerteza
13.
Biomed Phys Eng Express ; 8(5)2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35732139

RESUMO

Objective. Auto-contouring of organs at risk (OAR) is becoming more common in radiotherapy. An important issue in clinical decision making is judging the quality of the auto-contours. While recent studies considered contour quality by looking at geometric errors only, this does not capture the dosimetric impact of the errors. In this work, we studied the relationship between geometrical errors, the local dose and the dosimetric impact of the geometrical errors.Approach. For 94 head and neck patients, unmodified atlas-based auto-contours and clinically used delineations of the parotid glands and brainstem were retrieved. VMAT plans were automatically optimized on the auto-contours and evaluated on both contours. We defined the dosimetric impact on evaluation (DIE) as the difference in the dosimetric parameter of interest between the two contours. We developed three linear regression models to predict the DIE using: (1) global geometric metrics, (2) global dosimetric metrics, (3) combined local geometric and dosimetric metrics. For model (3), we next determined the minimal amount of editing information required to produce a reliable prediction. Performance was assessed by the root mean squared error (RMSE) of the predicted DIE using 5-fold cross-validation.Main results. In model (3), the median RMSE of the left parotid was 0.4 Gy using 5% of the largest editing vectors. For the right parotid and brainstem the results were 0.5 Gy using 10% and 0.4 Gy using 1% respectively. The median RMS of the DIE was 0.6 Gy, 0.7 Gy and 0.9 Gy for the left parotid, the right parotid and the brainstem, respectively. Model (3), combining local dosimetric and geometric quantities, outperformed the models that used only geometric or dosimetric information.Significance. We showed that the largest local errors plus the local dose suffice to accurately predict the dosimetric impact, opening the door to automated dosimetric QA of auto-contours.


Assuntos
Órgãos em Risco , Planejamento da Radioterapia Assistida por Computador , Cabeça , Humanos , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos
15.
Phys Med Biol ; 66(11)2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32217828

RESUMO

We developed and validated a dedicated small field back-projection portal dosimetry model for pretreatment andin vivoverification of stereotactic plans entailing small unflattened photon beams. For this purpose an aSi-EPID was commissioned as a small field dosimeter. Small field output factors for 6 MV FFF beams were measured using the PTW microDiamond detector and the Agility 160-leaf MLC from Elekta. The back-projection algorithm developed in our department was modified to better model the small field physics. The feasibility of small field portal dosimetry was validated via absolute point dose differences w.r.t. small static beams, and 5 hypofractionated stereotactic VMAT clinical plans measured with the OCTAVIUS 1000 SRS array dosimeter and computed with the treatment planning system Pinnacle v16.2. Dose reconstructions using the currently clinically applied back-projection model were also computed for comparison. We found that the latter yields underdosage of about -8% for square beams with cross section near 10 mm x 10 mm and about -6% for VMAT treatments with PTV volumes smaller than about 2cm3. With the methods described in this work such errors can be reduced to less than the ±3.0% recommendations for clinical use. Our results indicate that aSi-EPIDs can be used as accurate small field radiation dosimeters, offering advantages over point dose detectors, the correct positioning and orientation of which is challenging for routine clinical QA.


Assuntos
Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Algoritmos , Imageamento Tridimensional , Aceleradores de Partículas , Radiometria , Dosagem Radioterapêutica
16.
Phys Med Biol ; 66(10)2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33906177

RESUMO

Purpose. Auto-contouring (AC) is rapidly becoming standard practice for OAR contouring. However, in clinical practice, clinicians still need to manually check and correct contours. Anomaly detection systems (ADS) can aid the clinical decision process by suggesting which structures require corrections or not, greatly enhancing the value of AC. The purpose of this work is to develop and evaluate a decision support system for detecting anomalies in the case of parotid gland delineations. METHODS: Head and neck parotid gland delineations (1037 right, 1038 left), were retrieved from the Netherlands Cancer Institute (NKI) database. Morphological and image-based features were extracted from each patient's CT and structure set. An isolation forest model was initially trained on 70% of the data, of which 10% had synthetically generated anomalies and validated on the remaining 30% of clinical data. The ADS was tested on an independent set of 250 patients (Normal: 174, Anomalies: 76) and on a clinical autocontouring software. RESULTS: Applied to the validation set, the ADS system resulted in area under the curve (AUC) values of 0.93 and 0.94 for the parotid left and right respectively. Image features appeared more important than morphological, but using all features resulted marginally in the best model. Applied to the test set the ADS system reached an accuracy level of 0.83 and 0.81 for the parotid left and right respectively. The ADS was particularly sensitive to uniform expansions/contractions, misplacements, extra/missing slices and anisotropic over-contouring. CONCLUSION: Anomaly detection can serve as a powerful contour quality assurance tool, especially for cases of organ misplacement and over-contouring.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Neoplasias , Cabeça , Humanos , Glândula Parótida/diagnóstico por imagem
17.
Biochem Biophys Res Commun ; 392(1): 53-7, 2010 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-20056110

RESUMO

Mitogaligin, a protein encoded by galig, an internal cytotoxic gene of the galectin-3 locus, is mostly a mitochondrial protein. Mitochondrial targeting is due to an already identified mitochondrial localization signal. Interaction of mitogaligin with mitochondria leads to cytochrome c cytosolic leakage and ultimately to cell death. We have previously pointed out that mitogaligin can also be directed to the nucleus when the mitochondrial addressing signal is inactivated, indicating a possible dual intracellular localization of the protein. When expressed in the nucleus, mitogaligin exhibits also apoptotic properties leading to cell death. In this report, we show that nuclear addressing of mitogaligin depends on a sequence differing from classical signals containing basic, lysine or proline-tyrosine rich residues. The signal consists of a long sequence of amino acids residues based on a series of a short repetitive degenerated sequence.


Assuntos
Proteínas Sanguíneas/metabolismo , Núcleo Celular/metabolismo , Galectinas/metabolismo , Sinais de Localização Nuclear/metabolismo , Transporte Ativo do Núcleo Celular , Sequência de Aminoácidos , Proteínas Sanguíneas/química , Proteínas Sanguíneas/genética , Galectinas/química , Galectinas/genética , Células HeLa , Humanos , Dados de Sequência Molecular , Sinais de Localização Nuclear/química , Sinais de Localização Nuclear/genética , Estrutura Terciária de Proteína , Deleção de Sequência
18.
J Vis Exp ; (166)2020 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-33346196

RESUMO

The protocol described is based on a plug-transfer technique that allows accurate determination of microorganism quantities and their developmental stages. A specified number of spores are spread on an agar plate. This agar plate is incubated for a defined period to allow the fungi to reach the expected developmental stage, except for spores where incubation is not required. Agar plugs covered by spores, hyphae, or mycelium are next withdrawn and transferred onto agar media containing the antifungal compound to be tested either placed at a distance from the fungi or in contact. This method is applicable to test both liquid extracts and solid samples (powders). It is particularly well suited for quantifying the relative contributions of volatile and non-volatile agents in bioactive mixtures and for determining their effects, specifically on spores, early hyphae, and mycelium. The method is highly relevant for the characterization of the antifungal activity of biocontrol products, notably plant-derived products. Indeed, for plant treatment, the results can be used to guide the choice of mode of application and to establish the trigger thresholds.


Assuntos
Antifúngicos/análise , Antifúngicos/farmacologia , Fungos/efeitos dos fármacos , Controle Biológico de Vetores , Meios de Cultura , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Plantas/química , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/fisiologia , Volatilização
19.
Biochem Biophys Res Commun ; 378(4): 816-20, 2009 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-19071086

RESUMO

Galig, an internal gene to the galectin-3 gene, encodes two proteins and induces cell death in human cells. Mitogaligin, one of these proteins, contains a mitochondrial targeting sequence and promotes the release of cytochrome c into the cytosol. Here, we show that mitogaligin can also localize to nucleus. The nuclear form of mitogaligin induced cell death through a pathway exhibiting typical properties of apoptosis. These observations indicate for the first time that mitogaligin expresses cytotoxic properties not only when addressed to mitochondria but also when targeted to the nucleus.


Assuntos
Apoptose , Proteínas Sanguíneas/metabolismo , Núcleo Celular/metabolismo , Galectinas/metabolismo , Proteínas Sanguíneas/genética , Dano ao DNA , Galectinas/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células HeLa , Humanos , Mitocôndrias/metabolismo , Transporte Proteico , Proteína X Associada a bcl-2/metabolismo
20.
Environ Manage ; 44(6): 1043-52, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19548023

RESUMO

Since its establishment in 1903, the National Wildlife Refuge System (NWRS) has grown to 635 units and 37 Wetland Management Districts in the United States and its territories. These units provide the seasonal habitats necessary for migratory waterfowl and other species to complete their annual life cycles. Habitat conversion and fragmentation, invasive species, pollution, and competition for water have stressed refuges for decades, but the interaction of climate change with these stressors presents the most recent, pervasive, and complex conservation challenge to the NWRS. Geographic isolation and small unit size compound the challenges of climate change, but a combined emphasis on species that refuges were established to conserve and on maintaining biological integrity, diversity, and environmental health provides the NWRS with substantial latitude to respond. Individual symptoms of climate change can be addressed at the refuge level, but the strategic response requires system-wide planning. A dynamic vision of the NWRS in a changing climate, an explicit national strategic plan to implement that vision, and an assessment of representation, redundancy, size, and total number of units in relation to conservation targets are the first steps toward adaptation. This adaptation must begin immediately and be built on more closely integrated research and management. Rigorous projections of possible futures are required to facilitate adaptation to change. Furthermore, the effective conservation footprint of the NWRS must be increased through land acquisition, creative partnerships, and educational programs in order for the NWRS to meet its legal mandate to maintain the biological integrity, diversity, and environmental health of the system and the species and ecosystems that it supports.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Animais , Animais Selvagens , Ecossistema , Estados Unidos
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