Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Adv Sci (Weinh) ; 10(28): e2301011, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37551059

RESUMO

Oxidation states (OS) are the charges on atoms due to electrons gained or lost upon applying an ionic approximation to their bonds. As a fundamental property, OS has been widely used in charge-neutrality verification, crystal structure determination, and reaction estimation. Currently, only heuristic rules exist for guessing the oxidation states of a given compound with many exceptions. Recent work has developed machine learning models based on heuristic structural features for predicting the oxidation states of metal ions. However, composition-based oxidation state prediction still remains elusive so far, which has significant implications for the discovery of new materials for which the structures have not been determined. This work proposes a novel deep learning-based BERT transformer language model BERTOS for predicting the oxidation states for all elements of inorganic compounds given only their chemical composition. This model achieves 96.82% accuracy for all-element oxidation states prediction benchmarked on the cleaned ICSD dataset and achieves 97.61% accuracy for oxide materials. It is also demonstrated how it can be used to conduct large-scale screening of hypothetical material compositions for materials discovery.

2.
Front Oncol ; 12: 812159, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35237517

RESUMO

BACKGROUND: Sarcopenia is prognostic for survival in patients with head and neck cancer (HNC). However, identification of this high-risk feature remains challenging without computed tomography (CT) imaging of the abdomen or thorax. Herein, we establish sarcopenia thresholds at the C3 level and determine if C3 sarcopenia is associated with survival in patients with HNC. METHODS: This retrospective cohort study was conducted in consecutive patients with a squamous cell carcinoma of the head and neck with cross-sectional abdominal or neck imaging within 60 days prior to treatment. Measurement of cross-sectional muscle area at L3 and C3 levels was performed from CT imaging. Primary study outcome was overall survival. RESULTS: Skeletal muscle area at C3 was strongly correlated with the L3 level in both men (n = 188; r = 0.77; p < 0.001) and women (n = 65; r = 0.80; p < 0.001), and C3 sarcopenia thresholds of 14.0 cm2/m2 (men) and 11.1 cm2/m2 (women) were best predictive of L3 sarcopenia thresholds. Applying these C3 thresholds to a cohort of patients with neck imaging alone revealed that C3 sarcopenia was independently associated with reduced overall survival in men (HR = 2.63; 95% CI, 1.79, 3.85) but not women (HR = 1.18, 95% CI, 0.76, 1.85). CONCLUSIONS: This study identifies sarcopenia thresholds at the C3 level that best predict L3 sarcopenia in men and women. In HNC, C3-defined sarcopenia is associated with poor survival outcomes in men, but not women, suggesting sarcopenia may differentially affect men and women with HNC.

3.
J Mol Cell Cardiol ; 165: 115-129, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35041844

RESUMO

Dilated cardiomyopathy (DCM) is a heritable and genetically heterogenous disease often idiopathic and a leading cause of heart failure with high morbidity and mortality. DCM caused by RNA binding motif protein 20 (RBM20) mutations is diverse and needs a more complete mechanistic understanding. RBM20 mutation S637G (S639G in mice) is linked to severe DCM and early death in human patients. In this study, we generated a RBM20 S639G mutation knock-in (KI) mouse model to validate the function of S639G mutation and examine the underlying mechanisms. KI mice exhibited severe DCM and premature death with a ~ 50% mortality in two months old homozygous (HM) mice. KI mice had enlarged atria and increased ANP and BNP biomarkers. The S639G mutation promoted RBM20 trafficking and ribonucleoprotein (RNP) granules in the sarcoplasm. RNA Seq data revealed differentially expressed and spliced genes were associated with arrhythmia, cardiomyopathy, and sudden death. KI mice also showed a reduction of diastolic stiffness and impaired contractility at both the left ventricular (LV) chamber and cardiomyocyte levels. Our results indicate that the RBM20 S639G mutation leads to RNP granules causing severe heart failure and early death and this finding strengthens the novel concept that RBM20 cardiomyopathy is a RNP granule disease.


Assuntos
Cardiomiopatia Dilatada , Insuficiência Cardíaca , Animais , Cardiomiopatia Dilatada/metabolismo , Insuficiência Cardíaca/genética , Humanos , Camundongos , Mortalidade Prematura , Mutação , RNA , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Risco
4.
J Am Acad Dermatol ; 83(1): 71-77, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31931086

RESUMO

BACKGROUND: Tumor necrosis factor-α inhibitor (TNFi)-induced psoriasis is a paradoxic reaction characterized by the development of a psoriasiform rash that mimics idiopathic psoriasis subtypes both clinically and histologically. Few studies have investigated the histologic features of TNFi-induced psoriasis skin lesions, and most of these are limited by inclusion of few specimens. OBJECTIVE: We aimed to characterize histologic features of TNFi-induced psoriasis and identify histologic differences between TNFi-induced psoriasis and idiopathic psoriasis. METHODS: We characterized 60 biopsy specimens obtained from 47 unique patients at a single tertiary care referral center between 2004 and 2016 who developed TNFi-induced psoriasis, and we compared histologic features to those of 85 biopsy specimens from a control group of 85 patients with idiopathic psoriasis. RESULTS: The most common histologic reaction pattern in TNFi-induced psoriasis biopsy specimens was psoriasiform (80.0%). Five histologic parameters were significantly different in TNFi-induced psoriasis biopsy specimens compared with idiopathic psoriasis biopsy specimens: at least 3 dermal eosinophils per histologic section, neutrophils in the stratum corneum, neutrophils in the epidermis, papillary plate thinning, and absence of parakeratosis. LIMITATIONS: Inability to exclude lesion selection bias as a potential reason for some significant histologic differences. CONCLUSIONS: This study supports the idea that histologic differences exist between TNFi-induced psoriasis and idiopathic psoriasis may help distinguish between these conditions, especially for dermal eosinophil counts of 3 or greater.


Assuntos
Psoríase/induzido quimicamente , Psoríase/patologia , Pele/patologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Eosinófilos/patologia , Humanos , Contagem de Leucócitos , Neutrófilos/patologia
5.
Quant Imaging Med Surg ; 7(2): 187-194, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28516044

RESUMO

BACKGROUND: It is technically challenging to design compact yet sensitive miniature catheter radio frequency (RF) coils for endovascular interventional MR imaging. METHODS: In this work, a new design method for catheter RF coils is proposed based on the coaxial transmission line resonator (TLR) technique. Due to its distributed circuit, the TLR catheter coil does not need any lumped capacitors to support its resonance, which simplifies the practical design and construction and provides a straightforward technique for designing miniature catheter-mounted imaging coils that are appropriate for interventional neurovascular procedures. The outer conductor of the TLR serves as an RF shield, which prevents electromagnetic energy loss, and improves coil Q factors. It also minimizes interaction with surrounding tissues and signal losses along the catheter coil. To investigate the technique, a prototype catheter coil was built using the proposed coaxial TLR technique and evaluated with standard RF testing and measurement methods and MR imaging experiments. Numerical simulation was carried out to assess the RF electromagnetic field behavior of the proposed TLR catheter coil and the conventional lumped-element catheter coil. RESULTS: The proposed TLR catheter coil was successfully tuned to 64 MHz for proton imaging at 1.5 T. B1 fields were numerically calculated, showing improved magnetic field intensity of the TLR catheter coil over the conventional lumped-element catheter coil. MR images were acquired from a dedicated vascular phantom using the TLR catheter coil and also the system body coil. The TLR catheter coil is able to provide a significant signal-to-noise ratio (SNR) increase (a factor of 200 to 300) over its imaging volume relative to the body coil. CONCLUSIONS: Catheter imaging RF coil design using the proposed coaxial TLR technique is feasible and advantageous in endovascular interventional MR imaging applications.

6.
Nat Commun ; 7: 11046, 2016 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-26988139

RESUMO

In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh ß-strand of super-folder GFP and sfCherry, respectively. The small size of FP11-tags enables a cost-effective and scalable way to insert them into endogenous genomic loci via CRISPR-mediated homology-directed repair. Tandem arrangement FP11-tags allows proportional enhancement of fluorescence signal in tracking intraflagellar transport particles, or reduction of photobleaching for live microtubule imaging. Finally, we show the utility of tandem GFP11-tag in scaffolding protein oligomerization. These experiments illustrate the versatility of FP11-tag as a labelling tool as well as a multimerization-control tool for both imaging and non-imaging applications.


Assuntos
Proteínas de Fluorescência Verde/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Sobrevivência Celular , Fluorescência , Humanos , Multimerização Proteica , Coloração e Rotulagem
7.
Nucleic Acids Res ; 44(8): e75, 2016 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-26740581

RESUMO

In order to elucidate the functional organization of the genome, it is vital to directly visualize the interactions between genomic elements in living cells. For this purpose, we engineered the Cas9 protein from Staphylococcus aureus (SaCas9) for the imaging of endogenous genomic loci, which showed a similar robustness and efficiency as previously reported for Streptococcus pyogenes Cas9 (SpCas9). Imaging readouts allowed us to characterize the DNA-binding activity of SaCas9 and to optimize its sgRNA scaffold. Combining SaCas9 and SpCas9, we demonstrated two-color CRISPR imaging with the capability to resolve genomic loci spaced by <300 kb. Combinatorial color-mixing further enabled us to code multiple genomic elements in the same cell. Our results highlight the potential of combining SpCas9 and SaCas9 for multiplexed CRISPR-Cas9 applications, such as imaging and genome engineering.


Assuntos
Proteínas Associadas a CRISPR/genética , Sistemas CRISPR-Cas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Staphylococcus aureus/enzimologia , Streptococcus pyogenes/enzimologia , Animais , Linhagem Celular , Proteínas de Ligação a DNA/genética , Genoma/genética , Células HEK293 , Humanos , Camundongos , Staphylococcus aureus/genética , Streptococcus pyogenes/genética
8.
Sci Rep ; 4: 7025, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25395053

RESUMO

Hypervariable loops of HIV-1 Env protein gp120 are speculated to play roles in the conformational transition of Env to the receptor binding-induced metastable state. Structural analysis of full-length Env-based immunogens, containing the entire V2 loop, displayed tighter association between gp120 subunits, resulting in a smaller trimeric diameter than constructs lacking V2. A prominent basal quaternary location of V2 and V3' that challenges previous reports would facilitate gp41-independent gp120-gp120 interactions and suggests a quaternary mechanism of epitope occlusion facilitated by hypervariable loops. Deletion of V2 resulted in dramatic exposure of basal, membrane-proximal gp41 epitopes, consistent with its predicted basal location. The structural features of HIV-1 Env characterized here provide grounds for a paradigm shift in loop exposure and epitope occlusion, while providing substantive rationale for epitope display required for elicitation of broadly neutralizing antibodies, as well as substantiating previous pertinent literature disregarded in recent reports.


Assuntos
Epitopos/química , Fragmentos de Peptídeos/química , Multimerização Proteica , Produtos do Gene env do Vírus da Imunodeficiência Humana/química , Antígenos CD4/química , Antígenos CD4/metabolismo , Epitopos/genética , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/metabolismo , Humanos , Modelos Moleculares , Fragmentos de Peptídeos/genética , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Deleção de Sequência , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismo
9.
J Med Food ; 13(3): 535-47, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20521979

RESUMO

Numerous botanicals are purported to improve glucose metabolism and diabetic risk factors with varying degrees of supportive evidence. We investigated 203 commercially available botanical products representing 90 unique botanical species for effects on lipogenic activity in differentiating 3T3-L1 adipocytes. Anti-inflammatory activity of 21 of these products was further assessed in tumor necrosis factor alpha (TNFalpha)-stimulated, mature 3T3-L1 adipocytes. From these results, rho-isoalpha acids, Acacia nilotica bark, fennel, and wasabi were tested in the db/db mouse model. Fifty-nine percent of the 90 unique botanicals increased adipogenesis as did the standard troglitazone relative to the solvent controls. Botanical species with the greatest percentage of positive products were Centella asiatica, Panax quinquefolius, and Phyllanthus amarus at 100%, Vitis vinifera at 80%, Humulus lupulus at 71%, Aloe barbadensis at 66%, and Momordica charantia, Phaseolus vulgaris, and Punica granatum at 60%. All 21 subset samples inhibited TNFalpha-stimulated free fatty acid release and attenuated TNFalpha inhibition of adiponectin secretion. Both rho-isoalpha acids and A. nilotica reduced nonfasting glucose in the db/db mouse model, whereas A. nilotica also decreased nonfasting insulin levels. A post hoc analysis of the screening results indicated that the positive predictive value of the lipogenesis assay alone was 72%, while adding the criterion of a positive response in the anti-inflammatory assays increased this figure to 82%. Moreover, this large-scale evaluation demonstrates that antidiabetic, in vitro efficacy of botanicals is more a function of manufacturing or quality control differences than the presence of marker compounds and further underscores the need to develop functional as well as analytical bases for standardization of dietary supplements.


Assuntos
Adipócitos/efeitos dos fármacos , Diabetes Mellitus/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos , Extratos Vegetais/farmacologia , Plantas/química , Células 3T3-L1 , Adipócitos/imunologia , Adipócitos/fisiologia , Adipogenia/efeitos dos fármacos , Animais , Diabetes Mellitus/imunologia , Diabetes Mellitus/metabolismo , Diabetes Mellitus/fisiopatologia , Modelos Animais de Doenças , Ácidos Graxos/metabolismo , Insulina/metabolismo , Masculino , Camundongos , Camundongos Obesos , Extratos Vegetais/administração & dosagem , Fator de Necrose Tumoral alfa/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...