RESUMO
Pro-inflammatory autoantigen-specific CD4+ T helper (auto-Th) cells are central orchestrators of autoimmune diseases (AIDs). We aimed to characterize these cells in human AIDs with defined autoantigens by combining human leukocyte antigen (HLA)-tetramer-based and activation-based multidimensional ex vivo analyses. In aquaporin4-antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) patients, auto-Th cells expressed CD154, but proliferative capacity and pro-inflammatory cytokines were strongly reduced. Instead, exhaustion-associated co-inhibitory receptors were expressed together with FOXP3, the canonical regulatory T cell (Treg) transcription factor. Auto-Th cells responded in vitro to checkpoint inhibition and provided potent B cell help. Cells with the same exhaustion-like (ThEx) phenotype were identified in soluble liver antigen (SLA)-antibody-autoimmune hepatitis and BP180-antibody-positive bullous pemphigoid, AIDs of the liver and skin, respectively. While originally described in cancer and chronic infection, our data point to T cell exhaustion as a common mechanism of adaptation to chronic (self-)stimulation across AID types and link exhausted CD4+ T cells to humoral autoimmune responses, with implications for therapeutic targeting.
Assuntos
Autoantígenos , Doenças Autoimunes , Linfócitos T CD4-Positivos , Humanos , Autoantígenos/imunologia , Doenças Autoimunes/imunologia , Linfócitos T CD4-Positivos/imunologia , Fenótipo , Linfócitos T Reguladores/imunologia , Citocinas/metabolismo , Citocinas/imunologia , Autoanticorpos/imunologia , FemininoRESUMO
In an attempt to chart parallel sensory streams passing through the visual thalamus, we acquired a 100-trillion-voxel electron microscopy (EM) dataset and identified cohorts of retinal ganglion cell axons (RGCs) that innervated each of a diverse group of postsynaptic thalamocortical neurons (TCs). Tracing branches of these axons revealed the set of TCs innervated by each RGC cohort. Instead of finding separate sensory pathways, we found a single large network that could not be easily subdivided because individual RGCs innervated different kinds of TCs and different kinds of RGCs co-innervated individual TCs. We did find conspicuous network subdivisions organized on the basis of dendritic rather than neuronal properties. This work argues that, in the thalamus, neural circuits are not based on a canonical set of connections between intrinsically different neuronal types but, rather, may arise by experience-based mixing of different kinds of inputs onto individual postsynaptic cells.
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Corpos Geniculados/ultraestrutura , Rede Nervosa/ultraestrutura , Vias Neurais/fisiologia , Células Ganglionares da Retina/metabolismo , Animais , Axônios/metabolismo , Lógica Fuzzy , Corpos Geniculados/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Rede Nervosa/fisiologia , Vias Neurais/ultraestrutura , Sinapses , Córtex Visual/citologiaRESUMO
We describe automated technologies to probe the structure of neural tissue at nanometer resolution and use them to generate a saturated reconstruction of a sub-volume of mouse neocortex in which all cellular objects (axons, dendrites, and glia) and many sub-cellular components (synapses, synaptic vesicles, spines, spine apparati, postsynaptic densities, and mitochondria) are rendered and itemized in a database. We explore these data to study physical properties of brain tissue. For example, by tracing the trajectories of all excitatory axons and noting their juxtapositions, both synaptic and non-synaptic, with every dendritic spine we refute the idea that physical proximity is sufficient to predict synaptic connectivity (the so-called Peters' rule). This online minable database provides general access to the intrinsic complexity of the neocortex and enables further data-driven inquiries.
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Microscopia Eletrônica de Varredura/métodos , Microtomia/métodos , Neocórtex/ultraestrutura , Neurônios/ultraestrutura , Animais , Automação , Axônios/ultraestrutura , Dendritos/ultraestrutura , Camundongos , Neocórtex/citologia , Sinapses/ultraestrutura , Vesículas Sinápticas/ultraestruturaRESUMO
An animal's nervous system changes as its body grows from birth to adulthood and its behaviours mature1-8. The form and extent of circuit remodelling across the connectome is unknown3,9-15. Here we used serial-section electron microscopy to reconstruct the full brain of eight isogenic Caenorhabditis elegans individuals across postnatal stages to investigate how it changes with age. The overall geometry of the brain is preserved from birth to adulthood, but substantial changes in chemical synaptic connectivity emerge on this consistent scaffold. Comparing connectomes between individuals reveals substantial differences in connectivity that make each brain partly unique. Comparing connectomes across maturation reveals consistent wiring changes between different neurons. These changes alter the strength of existing connections and create new connections. Collective changes in the network alter information processing. During development, the central decision-making circuitry is maintained, whereas sensory and motor pathways substantially remodel. With age, the brain becomes progressively more feedforward and discernibly modular. Thus developmental connectomics reveals principles that underlie brain maturation.
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Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Caenorhabditis elegans/citologia , Conectoma , Modelos Neurológicos , Vias Neurais , Sinapses/fisiologia , Envelhecimento/metabolismo , Animais , Encéfalo/anatomia & histologia , Encéfalo/ultraestrutura , Caenorhabditis elegans/anatomia & histologia , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/ultraestrutura , Individualidade , Interneurônios/citologia , Microscopia Eletrônica , Neurônios/citologia , Comportamento EstereotipadoRESUMO
Maps of the nervous system that identify individual cells along with their type, subcellular components and connectivity have the potential to elucidate fundamental organizational principles of neural circuits. Nanometer-resolution imaging of brain tissue provides the necessary raw data, but inferring cellular and subcellular annotation layers is challenging. We present segmentation-guided contrastive learning of representations (SegCLR), a self-supervised machine learning technique that produces representations of cells directly from 3D imagery and segmentations. When applied to volumes of human and mouse cortex, SegCLR enables accurate classification of cellular subcompartments and achieves performance equivalent to a supervised approach while requiring 400-fold fewer labeled examples. SegCLR also enables inference of cell types from fragments as small as 10 µm, which enhances the utility of volumes in which many neurites are truncated at boundaries. Finally, SegCLR enables exploration of layer 5 pyramidal cell subtypes and automated large-scale analysis of synaptic partners in mouse visual cortex.
Assuntos
Neurópilo , Córtex Visual , Humanos , Animais , Camundongos , Neuritos , Células Piramidais , Aprendizado de Máquina Supervisionado , Processamento de Imagem Assistida por ComputadorRESUMO
Following on from the 2015 Lancet Oncology Commission on expanding global access to radiotherapy, Radiotherapy and theranostics: a Lancet Oncology Commission was created to assess the access and availability of radiotherapy to date and to address the important issue of access to the promising field of theranostics at a global level. A marked disparity in the availability of radiotherapy machines between high-income countries and low-income and middle-income countries (LMICs) has been identified previously and remains a major problem. The availability of a suitably trained and credentialled workforce has also been highlighted as a major limiting factor to effective implementation of radiotherapy, particularly in LMICs. We investigated initiatives that could mitigate these issues in radiotherapy, such as extended treatment hours, hypofractionation protocols, and new technologies. The broad implementation of hypofractionation techniques compared with conventional radiotherapy in prostate cancer and breast cancer was projected to provide radiotherapy for an additional 2·2 million patients (0·8 million patients with prostate cancer and 1·4 million patients with breast cancer) with existing resources, highlighting the importance of implementing new technologies in LMICs. A global survey undertaken for this Commission revealed that use of radiopharmaceutical therapy-other than 131I-was highly variable in high-income countries and LMICs, with supply chains, workforces, and regulatory issues affecting access and availability. The capacity for radioisotope production was highlighted as a key issue, and training and credentialling of health professionals involved in theranostics is required to ensure equitable access and availability for patient treatment. New initiatives-such as the International Atomic Energy Agency's Rays of Hope programme-and interest by international development banks in investing in radiotherapy should be supported by health-care systems and governments, and extended to accelerate the momentum generated by recognising global disparities in access to radiotherapy. In this Commission, we propose actions and investments that could enhance access to radiotherapy and theranostics worldwide, particularly in LMICs, to realise health and economic benefits and reduce the burden of cancer by accessing these treatments.
Assuntos
Acessibilidade aos Serviços de Saúde , Neoplasias , Humanos , Neoplasias/radioterapia , Países em Desenvolvimento , Radioterapia/economia , Nanomedicina Teranóstica , Disparidades em Assistência à Saúde , Radioterapia (Especialidade)/economia , Radioterapia (Especialidade)/educaçãoRESUMO
BACKGROUND: Amino acid production features of Corynebacterium glutamicum were extensively studied in the last two decades. Many metabolic pathways, regulatory and transport principles are known, but purely rational approaches often provide only limited progress in production optimization. We recently generated stable synthetic co-cultures, termed Communities of Niche-optimized Strains (CoNoS), that rely on cross-feeding of amino acids for growth. This setup has the potential to evolve strains with improved production by selection of faster growing communities. RESULTS: Here we performed adaptive laboratory evolution (ALE) with a CoNoS to identify mutations that are relevant for amino acid production both in mono- and co-cultures. During ALE with the CoNoS composed of strains auxotrophic for either L-leucine or L-arginine, we obtained a 23% growth rate increase. Via whole-genome sequencing and reverse engineering, we identified several mutations involved in amino acid transport that are beneficial for CoNoS growth. The L-leucine auxotrophic strain carried an expression-promoting mutation in the promoter region of brnQ (cg2537), encoding a branched-chain amino acid transporter in combination with mutations in the genes for the Na+/H+-antiporter Mrp1 (cg0326-cg0321). This suggested an unexpected link of Mrp1 to L-leucine transport. The L-arginine auxotrophic partner evolved expression-promoting mutations near the transcriptional start site of the yet uncharacterized operon argTUV (cg1504-02). By mutation studies and ITC, we characterized ArgTUV as the only L-arginine uptake system of C. glutamicum with an affinity of KD = 30 nM. Finally, deletion of argTUV in an L-arginine producer strain resulted in a faster and 24% higher L-arginine production in comparison to the parental strain. CONCLUSION: Our work demonstrates the power of the CoNoS-approach for evolution-guided identification of non-obvious production traits, which can also advance amino acid production in monocultures. Further rounds of evolution with import-optimized strains can potentially reveal beneficial mutations also in metabolic pathway enzymes. The approach can easily be extended to all kinds of metabolite cross-feeding pairings of different organisms or different strains of the same organism, thereby enabling the identification of relevant transport systems and other favorable mutations.
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Aminoácidos , Corynebacterium glutamicum , Aminoácidos/metabolismo , Leucina/metabolismo , Técnicas de Cocultura , Mutação , Arginina , Corynebacterium glutamicum/metabolismo , Engenharia Metabólica/métodosRESUMO
In vitro models of the developing brain such as three-dimensional brain organoids offer an unprecedented opportunity to study aspects of human brain development and disease. However, the cells generated within organoids and the extent to which they recapitulate the regional complexity, cellular diversity and circuit functionality of the brain remain undefined. Here we analyse gene expression in over 80,000 individual cells isolated from 31 human brain organoids. We find that organoids can generate a broad diversity of cells, which are related to endogenous classes, including cells from the cerebral cortex and the retina. Organoids could be developed over extended periods (more than 9 months), allowing for the establishment of relatively mature features, including the formation of dendritic spines and spontaneously active neuronal networks. Finally, neuronal activity within organoids could be controlled using light stimulation of photosensitive cells, which may offer a way to probe the functionality of human neuronal circuits using physiological sensory stimuli.
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Encéfalo/citologia , Vias Neurais/fisiologia , Neurogênese , Organoides/citologia , Organoides/efeitos da radiação , Linhagem Celular , Separação Celular , Córtex Cerebral/citologia , Córtex Cerebral/metabolismo , Dendritos , Perfilação da Expressão Gênica , Humanos , Técnicas In Vitro , Luz , Rede Nervosa/citologia , Rede Nervosa/efeitos da radiação , Vias Neurais/citologia , Vias Neurais/efeitos da radiação , Especificidade de Órgãos , Organoides/crescimento & desenvolvimento , Células Fotorreceptoras de Vertebrados/citologia , Células-Tronco Pluripotentes/citologia , Retina/citologia , Retina/metabolismo , Análise de Sequência de RNA , Análise de Célula Única , Fatores de Tempo , TranscriptomaRESUMO
The first phase of the Human Connectome Project pioneered advances in MRI technology for mapping the macroscopic structural connections of the living human brain through the engineering of a whole-body human MRI scanner equipped with maximum gradient strength of 300 mT/m, the highest ever achieved for human imaging. While this instrument has made important contributions to the understanding of macroscale connectional topology, it has also demonstrated the potential of dedicated high-gradient performance scanners to provide unparalleled in vivo assessment of neural tissue microstructure. Building on the initial groundwork laid by the original Connectome scanner, we have now embarked on an international, multi-site effort to build the next-generation human 3T Connectome scanner (Connectome 2.0) optimized for the study of neural tissue microstructure and connectional anatomy across multiple length scales. In order to maximize the resolution of this in vivo microscope for studies of the living human brain, we will push the diffusion resolution limit to unprecedented levels by (1) nearly doubling the current maximum gradient strength from 300 mT/m to 500 mT/m and tripling the maximum slew rate from 200 T/m/s to 600 T/m/s through the design of a one-of-a-kind head gradient coil optimized to minimize peripheral nerve stimulation; (2) developing high-sensitivity multi-channel radiofrequency receive coils for in vivo and ex vivo human brain imaging; (3) incorporating dynamic field monitoring to minimize image distortions and artifacts; (4) developing new pulse sequences to integrate the strongest diffusion encoding and highest spatial resolution ever achieved in the living human brain; and (5) calibrating the measurements obtained from this next-generation instrument through systematic validation of diffusion microstructural metrics in high-fidelity phantoms and ex vivo brain tissue at progressively finer scales with accompanying diffusion simulations in histology-based micro-geometries. We envision creating the ultimate diffusion MRI instrument capable of capturing the complex multi-scale organization of the living human brain - from the microscopic scale needed to probe cellular geometry, heterogeneity and plasticity, to the mesoscopic scale for quantifying the distinctions in cortical structure and connectivity that define cyto- and myeloarchitectonic boundaries, to improvements in estimates of macroscopic connectivity.
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Conectoma/métodos , Imagem de Difusão por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Masculino , Neuroimagem/métodos , Imagens de FantasmasRESUMO
Morphological and molecular characteristics determine the function of biological tissues. Attempts to combine immunofluorescence and electron microscopy invariably compromise the quality of the ultrastructure of tissue sections. We developed NATIVE, a correlated light and electron microscopy approach that preserves ultrastructure while showing the locations of multiple molecular moieties, even deep within tissues. This technique allowed the large-scale 3D reconstruction of a volume of mouse hippocampal CA3 tissue at nanometer resolution.
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Encéfalo/ultraestrutura , Imageamento Tridimensional/métodos , Microscopia Eletrônica/métodos , Microscopia de Fluorescência/métodos , Anticorpos de Domínio Único/imunologia , Animais , Feminino , Imunofluorescência , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Testicular germ cell tumours (GCTs) mostly affect young men at age 17-40. Although high cure rates can be achieved by orchiectomy and chemotherapy, GCTs can still be a lethal threat to young patients with metastases or therapy resistance. Thus, alternative treatment options are needed. Based on studies utilising GCT cell lines, the histone deacetylase inhibitor romidepsin is a promising therapeutic option, showing high toxicity at very low doses towards cisplatin-resistant GCT cells, but not fibroblasts or Sertoli cells. In this study, we extended our analysis of the molecular effects of romidepsin to deepen our understanding of the underlying mechanisms. Patients will benefit from these analyses, since detailed knowledge of the romidepsin effects allows for a better risk and side-effect assessment. We screened for changes in histone acetylation of specific lysine residues and analysed changes in the DNA methylation landscape after romidepsin treatment of the GCT cell lines TCam-2, 2102EP, NCCIT and JAR, while human fibroblasts were used as controls. In addition, we focused on the role of the dehydrogenase/reductase DHRS2, which was strongly up-regulated in romidepsin treated cells, by generating DHRS2-deficient TCam-2 cells using CRISPR/Cas9 gene editing. We show that DHRS2 is dispensable for up-regulation of romidepsin effectors (GADD45B, DUSP1, ZFP36, ATF3, FOS, CDKN1A, ID2) but contributes to induction of cell cycle arrest. Finally, we show that a combinatory treatment of romidepsin plus the gluccocorticoid dexamethasone further boosts expression of the romidepsin effectors and reduces viability of GCT cells more strongly than under single agent treatment. Thus, romidepsin and dexamethasone might represent a new combinatorial approach for treatment of GCT.
Assuntos
Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Carbonil Redutase (NADPH)/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Depsipeptídeos/farmacologia , Neoplasias Embrionárias de Células Germinativas/tratamento farmacológico , Neoplasias Testiculares/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Dexametasona/farmacologia , Inibidores de Histona Desacetilases/farmacologia , Humanos , Neoplasias Embrionárias de Células Germinativas/metabolismo , Neoplasias Testiculares/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Supported ionic liquid phase (SILP) catalysis enables a highly efficient, Ru-based, homogeneously catalyzed water-gas shift reaction (WGSR) between 100 °C and 150 °C. The active Ru-complexes have been found to exist in imidazolium chloride melts under operating conditions in a dynamic equilibrium, which is dominated by the [Ru(CO)3 Cl3 ]- complex. Herein we present state-of-the-art theoretical calculations to elucidate the reaction mechanism in more detail. We show that the mechanism includes the intermediate formation and degradation of hydrogen chloride, which effectively reduces the high barrier for the formation of the requisite dihydrogen complex. The hypothesis that the rate-limiting step involves water is supported by using D2 O in continuous catalytic WGSR experiments. The resulting mechanism constitutes a highly competitive alternative to earlier reported generic routes involving nucleophilic addition of hydroxide in the gas phase and in solution.
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BACKGROUND AND AIMS: The association of proximal small and diminutive hyperplastic polyps (HPs) with synchronous advanced neoplasia is not well-defined. However, sessile serrated polyps (SSPs), even when small, are known to portend a risk of synchronous neoplasia. Currently, the U.S. Multi-Society Task Force on Colorectal Cancer does not recommend a change in the surveillance interval when proximal small HPs are detected. We aimed to compare the rates of synchronous advanced neoplasia in a screening colonoscopy cohort of patients with small and then diminutive proximal HPs in comparison, first to a cohort absent any serrated or proximal HPs and then in comparison with a cohort with small proximal SSPs. METHODS: Consecutive screening colonoscopies were recorded between 2005 and 2010 at an academic medical center. Patients were divided into 3 mutually exclusive groups. Group 1 consisted of patients with at least 1 HP that was proximal to the sigmoid colon, <1 cm in endoscopic size, and up to 3 total HPs in number. Group 2 included patients without any proximal HPs or SSPs. Group 3 consisted of patients with 1 to 2 SSPs, with at least 1 being proximal to the sigmoid colon, that were <1 cm in endoscopic size and without dysplasia. Rates of synchronous advanced neoplasia in patients with small (<1 cm) and diminutive (≤5 mm) proximal HPs were compared with the rates for the other 2 groups. RESULTS: There were 482 of 2569 patients (18.8%) with a small proximal HP who met the criteria for Group 1. The rate of synchronous advanced neoplasia in patients with a small proximal HP (61/482, 12.7%) was significantly greater compared with the average risk in the non-serrated cohort (Group 2, 133/1878, 7.1%; P < .001). There was no significant difference in the rate of synchronous advanced neoplasia when the small proximal HP group was subdivided by size (≤5 mm, 51/404, 12.6% vs 6-9 mm, 10/78, 12.8%; P = 1.00). The rate of synchronous advanced neoplasia in patients with diminutive (≤5 mm) proximal HPs (51/404, 12.6%) was not significantly different from the rate observed with proximal SSPs of similar size (17/113, 15.0%; P = .529). CONCLUSION: Patients with small and diminutive proximal HPs tend to harbor higher rates of synchronous advanced neoplasia compared with those without any serrated lesions detected on screening colonoscopy. Surveillance outcomes for metachronous advanced neoplasia for patients with small proximal HPs deserves further study. The synchronous advanced neoplasia rate in patients with proximal diminutive HPs is similar to that of proximal diminutive SSPs and could have implications in a resect and discard strategy.
Assuntos
Adenoma/epidemiologia , Colo/patologia , Pólipos do Colo/epidemiologia , Neoplasias Colorretais/epidemiologia , Neoplasias Primárias Múltiplas/epidemiologia , Pólipos do Colo/patologia , Colonoscopia , Detecção Precoce de Câncer , Feminino , Humanos , Hiperplasia , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: A target goal for screening adenoma detection rate (S-ADR) of ≥ 25% has been set to define high-quality colonoscopy performance. However, there is no current accepted target goal for ADR in colorectal cancer (CRC) surveillance. This makes quality assessment challenging when physicians perform cancer surveillance colonoscopy but minimal screening procedures. METHODS: In this cohort study, consecutive colonoscopies performed at either Rush University Medical Center or Rush Oak Park Hospital by a gastroenterologist or colorectal surgeon in average risk screening population and CRC surveillance population were reviewed retrospectively from 2006 to 2012 and prospectively from 2013 to 2016. ADR in first surveillance colonoscopy following surgical resection of CRC (CRC-ADR) was reported in high-quality detectors (HQD) or low-quality detectors (LQD) based on achievement of 25% ADR in consecutive screening colonoscopy in average risk patients. Pearson's correlation was used to describe the association between individual S-ADR and CRC-ADR for colonoscopists. RESULTS: There was a very strong positive correlation (r = 0.88, p = 0.002) between ADR in average risk screening and first time CRC surveillance. For HQD as defined by S-ADR ≥ 25% (n = 10 colonoscopists), the CRC-ADR was 37.7% (78/207, SD 8%) which was very similar to their respective S-ADR of 33.4% (816/2440, p = 0.22). For LQD (n = 5 colonoscopists), the CRC-ADR was 20.2% (40/198) which was similar to their respective S-ADR of 20.1% (119/591, p = 0.99). The CRC-ADR was significantly higher for HQD than for LQD (37.7 vs. 20.2%, p < 0.0001). CONCLUSIONS: The major finding of this study is a defined CRC-ADR for HQD based on the ability to achieve S-ADR ≥ 25%. S-ADR strongly correlates with CRC-ADR. CRC-ADR is quite similar to the colonoscopists' respective S-ADR for both HQD and LQD. For colonoscopists who perform limited screening colonoscopies but do perform CRC surveillance colonoscopies, ADR metrics similar to S-ADR to assess quality in colonoscopy could be considered.
Assuntos
Adenoma/diagnóstico , Colonoscopia/métodos , Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer/métodos , Programas de Rastreamento/métodos , Vigilância da População , Adenoma/epidemiologia , Neoplasias Colorretais/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Estados Unidos/epidemiologiaRESUMO
BACKGROUND AND AIMS: Non-neoplastic polypectomies (NNPs) add pathology and procedural costs but do not reduce cancer risk and should be minimized. We sought to define the minimal non-neoplastic polypectomy rate (NNPR) for those colonoscopists achieving high-quality colorectal cancer screening based on adenoma detection rates (ADRs). METHODS: NNPRs for colonoscopists achieving high-quality adenoma detection rates were reported to determine minimal NNPR goals. Two approaches to tracking NNPR monitoring were compared: (1) total NNPR, an NNPR inclusive of all non-neoplastic specimens with exclusion of only hyperplastic polyp, sessile serrated polyp, and adenoma; and (2) normal tissue-only NNPR, an NNPR inclusive of those specimens with only normal colonic mucosa or lymphoid follicles. RESULTS: For those performing colonoscopy with high-quality ADRs (≥25%), half (6/12) of the colonoscopists had a total NNPR of ≤8.5% and 2 gastroenterologists had a total NNPR of ≤3.4%. The mean total NNPR of the cohort was 8.7% versus the normal tissue only NNPR, which was 7.5% (mean difference of 1.2%, standard deviation ± 0.97). The widest variation between total NNPR versus normal tissue only NNPR for any colonoscopist was 2.9%. The total NNPR ranged between 2.6% and 21.3% among 14 colonoscopists. CONCLUSIONS: Colonoscopy with a high-quality ADR can be achieved while maintaining a low total NNPR. A total NNPR, inclusive of all non-neoplastic specimens as an alternative to an approach in which all specimens require individual review in order to select out only normal tissue can be considered for monitoring of NNPR.
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Adenoma/diagnóstico , Colo/cirurgia , Pólipos do Colo/cirurgia , Colonoscopia/métodos , Neoplasias Colorretais/diagnóstico , Tecido Linfoide/cirurgia , Qualidade da Assistência à Saúde , Procedimentos Desnecessários , Adenoma/patologia , Idoso , Colo/patologia , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Detecção Precoce de Câncer , Feminino , Gastroenterologistas , Humanos , Hiperplasia , Tecido Linfoide/patologia , Masculino , Pessoa de Meia-IdadeRESUMO
PURPOSE: The purpose of this study is to report time points relevant to the neurosurgical management of posthemorrhagic hydrocephalus (PHH). METHODS: Data were collected retrospectively on 104 preterm infants with intraventricular hemorrhage (IVH) who received neurosurgical intervention for PHH at St. Louis Children's Hospital from 1994 to 2016. Kaplan-Meier curves were constructed for various endpoints. RESULTS: IVH grade on head ultrasound obtained through routine clinical care was II, III, and IV in 5 (4.8%), 33 (31.7%), and 66 (63.5%) of the patients, respectively. Neither IVH size nor location appeared to affect development of PHH. Days from birth to IVH, ventriculomegaly, temporizing neurosurgical procedure (TNP), and permanent neurosurgical intervention were 2.0 (95% CI 1.7-2.3), 3.0 (2.5-3.5), 24.0 (22.2-25.8), and 101.0 (90.4-111.6), respectively. Grades III and IV IVH did not differ in age at IVH diagnosis (Χ 2 (1 d.f.) = 1.32, p = 0.25), ventriculomegaly (Χ 2 = 0.73, p = 0.40), TNP (Χ 2 = 0.61, p = 0.43), or permanent intervention (Χ 2 = 2.48, p = 0.17). Ventricular reservoirs and ventriculosubgaleal shunts were used in 71 (68.3%) and 30 (28.8%), respectively. Eighty (76.9%) of the patients ultimately received a VPS. Five (4.8%) underwent a primary endoscopic third ventriculostomy (ETV), and two (1.9%) had ETV for a revision procedure. Four of the seven ETVs had choroid plexus cauterization. CONCLUSIONS: Although most infants who develop IVH and ventriculomegaly will do so within a few days of birth, at-risk infants should be observed for at least 4 weeks with serial head ultrasounds to monitor for PHH requiring surgery.
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Hemorragia Cerebral/complicações , Hidrocefalia/complicações , Hidrocefalia/epidemiologia , Hidrocefalia/cirurgia , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Estimativa de Kaplan-Meier , Masculino , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de RiscoRESUMO
Hydrocephalus (HC) is a common, debilitating neurological condition that requires urgent clinical decision-making. At present, neurosurgeons rely heavily on a patient's history, physical examination findings, neuroimaging, and clinical judgment to make the diagnosis of HC or treatment failure (e.g., shunt malfunction). Unfortunately, these tools, even in combination, do not eliminate subjectivity in clinical decisions. In order to improve the management of infants and children with HC, there is an urgent need for new biomarkers to complement currently available tools and enable clinicians to confidently establish the diagnosis of HC, assess therapeutic efficacy/treatment failure, and evaluate current and future developmental challenges, so that every child has access to the resources they need to optimize their outcome and quality of life.
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Biomarcadores , Líquido Cefalorraquidiano/metabolismo , Hidrocefalia/cirurgia , Hemorragia Cerebral/complicações , Humanos , Hidrocefalia/etiologia , Lactente , Recém-Nascido , Doenças do Prematuro/cirurgia , Pediatria , Qualidade de VidaRESUMO
The elementary reactions leading to the formation of the first carbon-carbon bond during early stages of the zeolite-catalyzed methanol conversion into hydrocarbons were identified by combining kinetics, spectroscopy, and DFT calculations. The first intermediates containing a C-C bond are acetic acid and methyl acetate, which are formed through carbonylation of methanol or dimethyl ether even in presence of water. A series of acid-catalyzed reactions including acetylation, decarboxylation, aldol condensation, and cracking convert those intermediates into a mixture of surface bounded hydrocarbons, the hydrocarbon pool, as well as into the first olefin leaving the catalyst. This carbonylation based mechanism has an energy barrier of 80â kJ mol(-1) for the formation of the first C-C bond, in line with a broad range of experiments, and significantly lower than the barriers associated with earlier proposed mechanisms.
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We integrate the all-electron electronic structure code FHI-aims into the general ChemShell package for solid-state embedding quantum and molecular mechanical (QM/MM) calculations. A major undertaking in this integration is the implementation of pseudopotential functionality into FHI-aims to describe cations at the QM/MM boundary through effective core potentials and therewith prevent spurious overpolarization of the electronic density. Based on numeric atomic orbital basis sets, FHI-aims offers particularly efficient access to exact exchange and second order perturbation theory, rendering the established QM/MM setup an ideal tool for hybrid and double-hybrid level density functional theory calculations of solid systems. We illustrate this capability by calculating the reduction potential of Fe in the Fe-substituted ZSM-5 zeolitic framework and the reaction energy profile for (photo-)catalytic water oxidation at TiO2(110).
RESUMO
The likelihood ratio (LR) is a probabilistic method that has been championed as a 'simple rule' for evaluating the probative value of forensic evidence in court. Intuitively, if the LR is greater than one then the evidence supports the prosecution hypothesis; if the LR is less than one it supports the defence hypothesis, and if the LR is equal to one then the evidence favours neither (and so is considered 'neutral'-having no probative value). It can be shown by Bayes' theorem that this simple relationship only applies to pairs of hypotheses for which one is the negation of the other (i.e. to mutually exclusive and exhaustive hypotheses) and is not applicable otherwise. We show how easy it can be - even for evidence experts - to use pairs of hypotheses that they assume are mutually exclusive and exhaustive but are not, and hence to arrive at erroneous conclusions about the value of evidence using the LR. Furthermore, even when mutually exclusive and exhaustive hypotheses are used there are extreme restrictions as to what can be concluded about the probative value of evidence just from a LR. Most importantly, while the distinction between source-level hypotheses (such as defendant was/was not at the crime scene) and offence-level hypotheses (defendant is/is not guilty) is well known, it is not widely understood that a LR for evidence about the former generally has no bearing on the LR of the latter. We show for the first time (using Bayesian networks) the full impact of this problem, and conclude that it is only the LR of the offence level hypotheses that genuinely determines the probative value of the evidence. We investigate common scenarios in which evidence has a LR of one but still has significant probative value (i.e. is not neutral as is commonly assumed). As illustration we consider the ramifications of these points for the case of Barry George. The successful appeal against his conviction for the murder of Jill Dando was based primarily on the argument that the firearm discharge residue (FDR) evidence, assumed to support the prosecution hypothesis at the original trial, actually had a LR equal to one and hence was 'neutral'. However, our review of the appeal transcript shows numerous examples of the problems with the use of hypotheses identified above. We show that if one were to follow the arguments recorded in the Appeal judgement verbatim, then contrary to the Appeal conclusion, the probative value of the FDR evidence may not have been neutral as was concluded.