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1.
Brief Bioinform ; 25(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38385872

RESUMO

Drug discovery and development constitute a laborious and costly undertaking. The success of a drug hinges not only good efficacy but also acceptable absorption, distribution, metabolism, elimination, and toxicity (ADMET) properties. Overall, up to 50% of drug development failures have been contributed from undesirable ADMET profiles. As a multiple parameter objective, the optimization of the ADMET properties is extremely challenging owing to the vast chemical space and limited human expert knowledge. In this study, a freely available platform called Chemical Molecular Optimization, Representation and Translation (ChemMORT) is developed for the optimization of multiple ADMET endpoints without the loss of potency (https://cadd.nscc-tj.cn/deploy/chemmort/). ChemMORT contains three modules: Simplified Molecular Input Line Entry System (SMILES) Encoder, Descriptor Decoder and Molecular Optimizer. The SMILES Encoder can generate the molecular representation with a 512-dimensional vector, and the Descriptor Decoder is able to translate the above representation to the corresponding molecular structure with high accuracy. Based on reversible molecular representation and particle swarm optimization strategy, the Molecular Optimizer can be used to effectively optimize undesirable ADMET properties without the loss of bioactivity, which essentially accomplishes the design of inverse QSAR. The constrained multi-objective optimization of the poly (ADP-ribose) polymerase-1 inhibitor is provided as the case to explore the utility of ChemMORT.


Assuntos
Aprendizado Profundo , Humanos , Desenvolvimento de Medicamentos , Descoberta de Drogas , Inibidores de Poli(ADP-Ribose) Polimerases
2.
Brief Bioinform ; 23(2)2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35212357

RESUMO

Structural information for chemical compounds is often described by pictorial images in most scientific documents, which cannot be easily understood and manipulated by computers. This dilemma makes optical chemical structure recognition (OCSR) an essential tool for automatically mining knowledge from an enormous amount of literature. However, existing OCSR methods fall far short of our expectations for realistic requirements due to their poor recovery accuracy. In this paper, we developed a deep neural network model named ABC-Net (Atom and Bond Center Network) to predict graph structures directly. Based on the divide-and-conquer principle, we propose to model an atom or a bond as a single point in the center. In this way, we can leverage a fully convolutional neural network (CNN) to generate a series of heat-maps to identify these points and predict relevant properties, such as atom types, atom charges, bond types and other properties. Thus, the molecular structure can be recovered by assembling the detected atoms and bonds. Our approach integrates all the detection and property prediction tasks into a single fully CNN, which is scalable and capable of processing molecular images quite efficiently. Experimental results demonstrate that our method could achieve a significant improvement in recognition performance compared with publicly available tools. The proposed method could be considered as a promising solution to OCSR problems and a starting point for the acquisition of molecular information in the literature.


Assuntos
Aprendizado Profundo , Estrutura Molecular , Redes Neurais de Computação
3.
Brief Bioinform ; 22(6)2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34427296

RESUMO

Computational methods have become indispensable tools to accelerate the drug discovery process and alleviate the excessive dependence on time-consuming and labor-intensive experiments. Traditional feature-engineering approaches heavily rely on expert knowledge to devise useful features, which could be costly and sometimes biased. The emerging deep learning (DL) methods deliver a data-driven method to automatically learn expressive representations from complex raw data. Inspired by this, researchers have attempted to apply various deep neural network models to simplified molecular input line entry specification (SMILES) strings, which contain all the composition and structure information of molecules. However, current models usually suffer from the scarcity of labeled data. This results in a low generalization ability of SMILES-based DL models, which prevents them from competing with the state-of-the-art computational methods. In this study, we utilized the BiLSTM (bidirectional long short term merory) attention network (BAN) in which we employed a novel multi-step attention mechanism to facilitate the extracting of key features from the SMILES strings. Meanwhile, SMILES enumeration was utilized as a data augmentation method in the training phase to substantially increase the number of labeled data and enlarge the probability of mining more patterns from complex SMILES. We again took advantage of SMILES enumeration in the prediction phase to rectify model prediction bias and provide a more accurate prediction. Combined with the BAN model, our strategies can greatly improve the performance of latent features learned from SMILES strings. In 11 canonical absorption, distribution, metabolism, excretion and toxicity-related tasks, our method outperformed the state-of-the-art approaches.


Assuntos
Quimioinformática/métodos , Aprendizado Profundo , Descoberta de Drogas/métodos , Software , Algoritmos , Desenvolvimento de Medicamentos , Projetos de Pesquisa
4.
Brief Bioinform ; 22(6)2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33951729

RESUMO

MOTIVATION: Accurate and efficient prediction of molecular properties is one of the fundamental issues in drug design and discovery pipelines. Traditional feature engineering-based approaches require extensive expertise in the feature design and selection process. With the development of artificial intelligence (AI) technologies, data-driven methods exhibit unparalleled advantages over the feature engineering-based methods in various domains. Nevertheless, when applied to molecular property prediction, AI models usually suffer from the scarcity of labeled data and show poor generalization ability. RESULTS: In this study, we proposed molecular graph BERT (MG-BERT), which integrates the local message passing mechanism of graph neural networks (GNNs) into the powerful BERT model to facilitate learning from molecular graphs. Furthermore, an effective self-supervised learning strategy named masked atoms prediction was proposed to pretrain the MG-BERT model on a large amount of unlabeled data to mine context information in molecules. We found the MG-BERT model can generate context-sensitive atomic representations after pretraining and transfer the learned knowledge to the prediction of a variety of molecular properties. The experimental results show that the pretrained MG-BERT model with a little extra fine-tuning can consistently outperform the state-of-the-art methods on all 11 ADMET datasets. Moreover, the MG-BERT model leverages attention mechanisms to focus on atomic features essential to the target property, providing excellent interpretability for the trained model. The MG-BERT model does not require any hand-crafted feature as input and is more reliable due to its excellent interpretability, providing a novel framework to develop state-of-the-art models for a wide range of drug discovery tasks.


Assuntos
Modelos Teóricos , Redes Neurais de Computação
5.
J Chem Inf Model ; 63(8): 2345-2359, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-37000044

RESUMO

The n-octanol/buffer solution distribution coefficient at pH = 7.4 (log D7.4) is an indicator of lipophilicity, and it influences a wide variety of absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties and druggability of compounds. In log D7.4 prediction, graph neural networks (GNNs) can uncover subtle structure-property relationships (SPRs) by automatically extracting features from molecular graphs that facilitate the learning of SPRs, but their performances are often limited by the small size of available datasets. Herein, we present a transfer learning strategy called pretraining on computational data and then fine-tuning on experimental data (PCFE) to fully exploit the predictive potential of GNNs. PCFE works by pretraining a GNN model on 1.71 million computational log D data (low-fidelity data) and then fine-tuning it on 19,155 experimental log D7.4 data (high-fidelity data). The experiments for three GNN architectures (graph convolutional network (GCN), graph attention network (GAT), and Attentive FP) demonstrated the effectiveness of PCFE in improving GNNs for log D7.4 predictions. Moreover, the optimal PCFE-trained GNN model (cx-Attentive FP, Rtest2 = 0.909) outperformed four excellent descriptor-based models (random forest (RF), gradient boosting (GB), support vector machine (SVM), and extreme gradient boosting (XGBoost)). The robustness of the cx-Attentive FP model was also confirmed by evaluating the models with different training data sizes and dataset splitting strategies. Therefore, we developed a webserver and defined the applicability domain for this model. The webserver (http://tools.scbdd.com/chemlogd/) provides free log D7.4 prediction services. In addition, the important descriptors for log D7.4 were detected by the Shapley additive explanations (SHAP) method, and the most relevant substructures of log D7.4 were identified by the attention mechanism. Finally, the matched molecular pair analysis (MMPA) was performed to summarize the contributions of common chemical substituents to log D7.4, including a variety of hydrocarbon groups, halogen groups, heteroatoms, and polar groups. In conclusion, we believe that the cx-Attentive FP model can serve as a reliable tool to predict log D7.4 and hope that pretraining on low-fidelity data can help GNNs make accurate predictions of other endpoints in drug discovery.


Assuntos
Descoberta de Drogas , Halogênios , 1-Octanol , Aprendizagem , Redes Neurais de Computação
6.
Pancreatology ; 20(1): 95-100, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31786057

RESUMO

OBJECTIVES: FOLFIRINOX (FFX) or abraxane plus gemcitabine (AG)-based chemotherapy is used widely as firstline treatment for patients with pancreatic cancer. However, their use in the elderly is discouraged because of adverse events. More clinical data about the therapeutic response and tolerability to FFX or AG in elderly patents (over 70 years old) are required. METHODS: Patients with advanced pancreatic cancer (n = 203; 131 metastatic pancreatic cancer patients (MPC) and 72 locally advanced pancreatic cancer patients (LAPC)) were treated using modified-FFX (mFFX) or AG and mFFX sequentially. The patients were grouped according to their age, patients below 70 years old and patients above 70 years old. The objective response rate (ORR), disease control rate (DCR), progression free survival (PFS), overall survival (OS) and adverse events were compared between the groups. RESULTS: The ORRs in the elderly and in patients below 70 were similar (30.0% versus 32.3%). The median OS and PFS were also similar between the groups (mOS 13.3 m vs 12.7 m, p = 0.729, HR 0.874 (95% CI 0.5310 to 1.438); mPFS mPFS 10.6 m vs 10.3 m, p = 0.363, HR 0.800 (95% CI 0.4954 to 1.293)). However, the elderly patients suffered a higher incidence of severe adverse events (50% vs. 28.3%). CONCLUSIONS: These data could provide guidance for chemotherapy use in elderly patients with advanced pancreatic cancer. Age did not affect treatment outcome; however, supportive treatment is very important for elderly patients receiving chemotherapy.


Assuntos
Paclitaxel Ligado a Albumina/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxicitidina/análogos & derivados , Neoplasias Pancreáticas/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/uso terapêutico , Desoxicitidina/administração & dosagem , Desoxicitidina/uso terapêutico , Fluoruracila/uso terapêutico , Humanos , Irinotecano/uso terapêutico , Leucovorina/uso terapêutico , Oxaliplatina/uso terapêutico , Gencitabina
7.
Acta Pharmacol Sin ; 41(6): 825-834, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32066885

RESUMO

Chalcomoracin (CMR) is a kind of Diels-Alder adduct extracted from the mulberry leaves. Recent studies showed that CMR has a broad spectrum of anticancer activities and induces paraptosis in breast cancer and prostate cancer cells. In this study, we investigated the effects of CMR against human non-small cell lung cancer cells and the underlying mechanisms. We found that CMR dose-dependently inhibited the proliferation of human lung cancer H460, A549 and PC-9 cells. Furthermore, exposure to low and median doses of CMR induced paraptosis but not apoptosis, which was presented as the formation of extensive cytoplasmic vacuolation with increased expression of endoplasmic reticulum stress markers, Bip and Chop, as well as activation of MAPK pathway in the lung cancer cells. Knockdown of Bip with siRNA not only reduced the cell-killing effect of CMR, but also decreased the percentage of cytoplasmic vacuoles in H460 cells. Moreover, CMR also increased the sensitivity of lung cancer cells to radiotherapy through enhanced endoplasmic reticulum stress. In lung cancer H460 cell xenograft nude mice, combined treatment of CMR and radiation caused greatly enhanced tumor growth inhibition with upregulation of endoplasmic reticulum stress proteins and activation of pErk in xenograft tumor tissue. These data demonstrate that the anticancer activity and radiosensitization effect of CMR result from inducing paraptosis, suggesting that CMR could be considered as a potential anticancer agent and radiation sensitizer in the future cancer therapeutics.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Benzofuranos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Neoplasias Pulmonares/terapia , Células A549 , Animais , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Nus , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neoplasias Experimentais/terapia , Células Tumorais Cultivadas
8.
Cryobiology ; 94: 18-25, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32413358

RESUMO

A droplet-vitrification protocol was described for cryopreservation of shoot tips of kiwifruit 'Yuxiang' (Actinidia chinensis var. deliciosa). No significant differences were found in root formation and shoot growth between the in vitro-derived shoots (the control) and cryo-derived ones when cultured in vitro. No significant differences were detected in survival and vegetative growth between the in vitro-derived plants (the control) and cryo-derived ones after re-establishment in greenhouse conditions. Inter-simple sequence repeat (ISSR) and amplified fragment length polymorphism (AFLP) did not detect any polymorphic bands in the cryo-derived shoots when cultured in vitro and the cryo-derived plants after re-establishment in greenhouse conditions. These data indicate rooting ability, vegetative growth and genetic stability are maintained in the cryo-derived kiwifruit plants recovered from the droplet-vitrification cryopreservation. Methylation sensitive amplification polymorphism (MSAP) detected 12.8% and 1.6% DNA methylation in the cryo-derived shoots when cultured in vitro and the cryo-derived plants after re-established in greenhouse conditions, respectively. This droplet-vitrification was applied to five cultivars and three rootstocks belonging to A. chinensis var. deliciosa, A. chinensis var. chinensis, A. macrosperma, A. polygama and A. valvata. The highest (68.3%) and lowest (22.5%) shoot regrowth were obtained in A. macrosperma and A. chinensis var. chinensis 'Jinmi', respectively, with an average of 46.4% shoot regrowth obtained across the eight genotypes. The droplet-vitrification protocol described here can be considered the most applicable cryopreservation method so far reported for the genus Actinidia. Results reported here provide theoretical and technical supports for setting up cryo-banks of genetic resources of Actinidia spp.


Assuntos
Actinidia , Criopreservação/métodos , Brotos de Planta , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Metilação de DNA , Epigênese Genética , Genótipo , Vitrificação
9.
BMC Cancer ; 15: 917, 2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26582454

RESUMO

BACKGROUND: Standardized chemotherapy used in cancer patients with severe kidney insufficiency is ineffective. Although there are some pharmacokinetic studies on cyclophosphamide in kidney insufficiency patients, to the best of our knowledge, the pharmacokinetics and safety of combination of cyclophosphamide and docetaxel as postoperative chemotherapy in a patient with early stage breast cancer undergoing hemodialysis is unclear thus far. CASE PRESENTATION: The patient received regular TC regimen (cyclophosphamide 600 mg/m2, docetaxel 75 mg/m2). She underwent hemodialysis 48 h after chemotherapy. Blood samples at multiple time-points were collected for determination of plasma levels of cyclophosphamide and docetaxel. Pharmacokinetic analyses indicated that compared with the reference data, the in vivo half-life (66.96 h) and drug exposure (150%) of cyclophosphamide significantly increased; however, pharmacokinetic parameters of docetaxel was unaffected. Patient developed grade I thrombocytopenia and grade III leukopenia without any other severe adverse reactions. In total, four cycles of treatment were completed. After the chemotherapy, the patient received tamoxifen as endocrine therapy for one and a half years. No recurrence was reported. CONCLUSION: These results suggest that the standard TC regimen is mostly safe and could be used as postoperative adjuvant chemotherapy for hemodialysis patients with early stage breast cancer.


Assuntos
Antineoplásicos/farmacocinética , Neoplasias da Mama/tratamento farmacológico , Ciclofosfamida/farmacocinética , Diálise Renal , Insuficiência Renal Crônica/metabolismo , Taxoides/farmacocinética , Antineoplásicos/efeitos adversos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/cirurgia , Ciclofosfamida/efeitos adversos , Docetaxel , Feminino , Humanos , Pessoa de Meia-Idade , Período Pós-Operatório , Insuficiência Renal Crônica/terapia , Taxoides/efeitos adversos
10.
Pharmazie ; 70(4): 213-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26012249

RESUMO

A series of novel ocotillol-type furoxan derivatives was synthesized by coupling various furoxans to 3-OH of 6-deoxy ocotillol, and their in vitro nitric oxide (NO) releasing capability was studied. The discharge of NO was examined after 30 min at two different concentrations, the results showed that all of the compounds tested could release NO in a dose-dependent manner. All of the synthesized compounds released similar amounts of NO at 100 µM, whereas at 500 µM these compounds showed more difference, in which compound II1, II3, II4, III2 displayed higher potency in releasing NO at this concentration. Analysis of the in vitro data showed that the derivatives bearing the same furoxan group on different ocotillol cores possessed various NO releasing capacity, suggesting that the structure of carrier of NO releasing groups may affect the NO release. Indeed, except compound II2, 24(S)-6-deoxy ocotillol derivatives from compound 6 with different furoxan substitutions at 3-OH and III2 displayed enhanced NO releasing capacity, compared to other compounds derived from compounds 5 and 9. The results illustrated that the functional group and the stereochemistry on the ocotillol structure may affect the NO release of furoxans.


Assuntos
Ginsenosídeos/síntese química , Ginsenosídeos/farmacologia , Doadores de Óxido Nítrico/síntese química , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/química , Oxidiazóis/síntese química , Oxidiazóis/farmacologia , Desenho de Fármacos , Indicadores e Reagentes , Nitratos/química , Nitritos/química , Relação Estrutura-Atividade
11.
World J Clin Cases ; 10(28): 10236-10243, 2022 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-36246828

RESUMO

BACKGROUND: Hepatoid adenocarcinoma of the lung (HAL) is an extremely rare malignant tumor, and many patients with HAL exhibit high levels of alpha-fetoprotein (AFP) expression. Currently, there is no standardized treatment strategy for advanced HAL and its prognosis is poor. CASE SUMMARY: We report a 55-year-old man with unresectable AFP-related HAL. The largest cross-sectional area of the mass in the upper lobe of the left lung at the beginning of treatment was 8.46 cm × 6.53 cm. The patient's serum AFP level was 9283 ng/mL. The mass increased in size to 8.86 cm × 8.21 cm after two courses of platinum-based combination chemotherapy and immunotherapy, and serum AFP reached its highest level (71232.2 ng/mL). The patient was treated with sorafenib (400 mg twice daily, per os). Forty days later, the mass was reduced to 5.63 cm × 5.29 cm and serum AFP level dropped to 786.8 ng/mL. The patient achieved partial remission for > 9 mo with sorafenib and an excellent biomarker response, as well as survival > 13 mo, which is among the longest reported for unresectable stage IV HAL. CONCLUSION: This is the first report to document successful treatment of unresectable AFP-related HAL with single-agent sorafenib after multiline therapy.

12.
World J Clin Cases ; 10(8): 2497-2503, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35434068

RESUMO

BACKGROUND: Immune checkpoint inhibitors (ICIs) targeting the programmed death (PD)-1 pathway have substantially changed the clinical management of metastatic urothelial carcinoma (mUC); however, the response rate remains low. There are ongoing efforts to identify robust biomarkers that can effectively predict the treatment response to ICIs. Previous studies have suggested that ERBB2/3 mutations are associated with the efficacy of ICIs in gallbladder carcinoma. CASE SUMMARY: We present a 59-year-old man with mUC harboring ERBB2/3 mutations (in-frame insertion of ERBB2 and ERBB3 amplification), negative PD-ligand 1 expression, and low tumor mutation burden. He received anti-PD-1 antibodies and paclitaxel as second-line treatment. After two cycles of treatment, the lung metastases had significantly shrunk, achieving good partial remission. After six cycles of combination therapy, the patient received sindilimab 200 mg once every 3 wk as maintenance monotherapy. At the last follow-up, the patient continued to exhibit a partial response and progression-free survival for as long as 19 mo. CONCLUSION: ERBB2/3 mutations may represent a predictive biomarker for selecting a subgroup of mUC patients who will benefit from ICIs.

13.
Eur J Pharmacol ; 932: 175236, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36044971

RESUMO

Diabetic cardiomyopathy is a diabetic complication with complicated pathophysiological changes and pathogenesis and difficult treatment. Sodium houttuyfonate is the adduct of sodium bisulfite and houttuynin, the main volatile component in Houttuynia cordata Thunb, possesses a variety of activities including multiple interventions on inhibiting ventricular remodeling. The study aims to explore effect of sodium houttuyfonate on diabetic myocardial injury and its underlying mechanisms. The diabetes model was established by intraperitoneal injection of streptozotocin at a dose of 85 mg/kg. By intragastric administration for 26 days, sodium houttuyfonate (50 and 100 mg/kg/d) reversed the abnormal serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol and low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio, improved the abnormal levels of serum aspartate aminotransferase and brain natriuretic peptide, reduced electrocardiogram P-R and QRS interval extension, accelerated the heart rate, decreased serum malondialdehyde content, up-regulated the myocardial energy metabolism including elevated the contents of ATP, ADP, total adenine nucleotides and phosphocreatine in myocardium, decreased AMP/ATP ratio, elevated myocardial Ca2+-Mg2+-ATPase activity, and down-regulated the mRNA expressions of AMP protein activation kinase α2 (AMPK-α2) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). In a conclusion, these results suggest that sodium houttuyfonate can improve cardiac energy metabolism disorder caused by diabetes by increasing cardiac Ca2+-Mg2+-ATPase activity and regulating AMPK signaling pathway, and then attenuates cardiac injury caused by hyperglycemia. In addition, sodium houttuyfonate also has the effects of anti-oxidation and improving abnormal levels of blood lipid.


Assuntos
Diabetes Mellitus Experimental , Traumatismos Cardíacos , Proteínas Quinases Ativadas por AMP/metabolismo , Difosfato de Adenosina/metabolismo , Monofosfato de Adenosina , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Alcanos , Animais , Aspartato Aminotransferases/metabolismo , Colesterol , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Metabolismo Energético , Traumatismos Cardíacos/tratamento farmacológico , Traumatismos Cardíacos/prevenção & controle , Lipoproteínas HDL , Lipoproteínas LDL/metabolismo , Malondialdeído , Peptídeo Natriurético Encefálico/metabolismo , PPAR gama/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Fosfocreatina/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Estreptozocina , Sulfitos , Triglicerídeos
14.
Ying Yong Sheng Tai Xue Bao ; 33(11): 2963-2970, 2022 Oct.
Artigo em Zh | MEDLINE | ID: mdl-36384830

RESUMO

Elucidating the interannual variation of soil organic nitrogen fractions and its response to straw returning is of great significance for rational regulation of soil organic nitrogen pool and sustainable soil utilization. We conducted a field microcosm experiment with typic hapludoll soil at the National Field Observation and Research Station of Shenyang Agroecosystems. Three treatments were set, including nitrogen fertilizer addition (200 kg N·hm-2, the same in other treatments), nitrogen fertilizer addition with 50% straw return, and nitrogen fertilizer addition with 100% straw return. We classified soil organic nitrogen fractions in the 1st, 3rd, 6th, and 9th years of the experiment by using the Bremner acid hydrolysis method. The results showed that the content of amino acid nitrogen increased with the tillage years, with an increase rate of 39.8% compared with 1st year. The content of hydrolyzable unknown nitrogen increased by 10.8% compared with 1st year, which reached the highest in the 3rd year. The content of total soil nitrogen and other organic nitrogen fractions showed limited variation with tillage years. The proportion of hydrolyzable total nitrogen that is relatively easy to mineralize in the total soil nitrogen gradually increased with the tillage years, and that of relatively stable acid insoluble nitrogen to total soil nitrogen gradually decreased, indicating that soil nitrogen availability increased with the tillage years, which would facilitate the soil nitrogen supply capacity. Compared with the treatment without straw returning, adding straw improved soil total nitrogen and each hydrolyzable nitrogen contents, with such positive effect be stronger under the treatment with heavier straw returning. The effect of straw returning on hydrolyzable nitrogen fractions mainly occurred in the 6th and 9th years. The components of soil total nitrogen that have been increased were mainly the amino acid nitrogen and hydrolyzed unknown nitrogen, resulting in increased proportion of hydrolyzable nitrogen. Straw returning could increase soil nitrogen pool and improve soil nitrogen conservation and supply capacity.


Assuntos
Nitrogênio , Solo , Solo/química , Nitrogênio/análise , Fertilizantes , Agricultura/métodos , Aminoácidos
15.
Research (Wash D C) ; 2022: 0004, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-39285949

RESUMO

Accurate prediction of pharmacological properties of small molecules is becoming increasingly important in drug discovery. Traditional feature-engineering approaches heavily rely on handcrafted descriptors and/or fingerprints, which need extensive human expert knowledge. With the rapid progress of artificial intelligence technology, data-driven deep learning methods have shown unparalleled advantages over feature-engineering-based methods. However, existing deep learning methods usually suffer from the scarcity of labeled data and the inability to share information between different tasks when applied to predicting molecular properties, thus resulting in poor generalization capability. Here, we proposed a novel multitask learning BERT (Bidirectional Encoder Representations from Transformer) framework, named MTL-BERT, which leverages large-scale pre-training, multitask learning, and SMILES (simplified molecular input line entry specification) enumeration to alleviate the data scarcity problem. MTL-BERT first exploits a large amount of unlabeled data through self-supervised pretraining to mine the rich contextual information in SMILES strings and then fine-tunes the pretrained model for multiple downstream tasks simultaneously by leveraging their shared information. Meanwhile, SMILES enumeration is used as a data enhancement strategy during the pretraining, fine-tuning, and test phases to substantially increase data diversity and help to learn the key relevant patterns from complex SMILES strings. The experimental results showed that the pretrained MTL-BERT model with few additional fine-tuning can achieve much better performance than the state-of-the-art methods on most of the 60 practical molecular datasets. Additionally, the MTL-BERT model leverages attention mechanisms to focus on SMILES character features essential to target properties for model interpretability.

16.
J Agric Food Chem ; 69(20): 5618-5627, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-33979145

RESUMO

Natural products with minor side effects have been reported to be an effective adjuvant therapy for glucose and lipid metabolism disorders. Chrysin, a flavone, has a wide range of physiological effects, such as antioxidant, anti-inflammatory, anti-diabetes, anti-hyperlipidemia, and hepatoprotective. This study was designed to explore the effects and mechanism of chrysin on metabolic syndrome using insulin-resistant HepG2 cells and HFD/STZ-induced C57BL/6J mice. The results indicated that chrysin significantly decreased insulin resistance, oxidative stress, inflammation, and liver injury. In addition, chrysin improved glycogen synthesis and fatty acid oxidation and inhibited gluconeogenesis and fatty acid synthesis by regulating GSK3ß, G6Paes, PEPCK, SREBP1, FAS, and ACC1. Furthermore, the results of western blot and real-time PCR experiments demonstrated that chrysin modulated glucose and lipid metabolism through the AMPK/PI3K/AKT signaling pathway. Treatment with the AMPK inhibitor verified that AMPK activation is positively correlated with chrysin activity on glycolipid metabolism. This study confirms that chrysin is a potential treatment for glucose and lipid metabolism disorders.


Assuntos
Resistência à Insulina , Transtornos do Metabolismo dos Lipídeos , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Flavonoides , Glucose , Células Hep G2 , Humanos , Insulina/metabolismo , Metabolismo dos Lipídeos , Camundongos , Camundongos Endogâmicos C57BL , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais
17.
World J Clin Cases ; 8(3): 594-599, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32110671

RESUMO

BACKGROUND: Targeted treatments may greatly affect the natural history of urothelial carcinoma based on their pharmacokinetics. A phase II trial has explored the combination of cytotoxic chemotherapy with the anti-HER-2 monoclonal antibody trastuzumab in selected patients with metastatic bladder cancer, but it failed. CASE SUMMARY: Here, we report a case of recurrent urothelial bladder carcinoma (UBC) in a patient who has undergone three operations, and further illuminate its diagnosis and treatment. The diagnosis of UBC was rendered according to the pathological indices. Next-generation sequencing on formalin fixed paraffin-embedded (FFPE) tissue was also performed and suggested HER2 gene amplification in the FFPE tissue. Based on HER2 gene amplification in FFPE, the patient was treated with chemotherapy in combination with trastuzumab after his third surgery. Fortunately, the patient got a clinically complete remission to trastuzumab for 34 mo. CONCLUSION: There is not enough clinical evidence for incorporating trastuzumab in routine treatment of UBC. This case hinted that recurrent UBC patients with HER2 gene amplification may benefit from targeted trastuzumab. Further studies are needed to further investigate the status of HER2 gene and better determine trastuzumab in the management of UBC.

18.
World J Clin Cases ; 8(24): 6524-6528, 2020 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-33392340

RESUMO

BACKGROUND: Idiopathic adulthood ductopenia (IAD) is a chronic cholestatic liver disease of unknown etiology that usually presents as unexplained jaundice. It is characterized by adult onset, lack of autoantibodies, inflammatory bowel disease and loss of interlobular bile ducts. CASE SUMMARY: This case presents a 27-year-old woman with elevation of transaminases and alkaline phosphatase without clinical symptoms. Five years ago, the patient had abnormal transaminases but no cholestasis. Three months before admission, physical examination revealed an increase in transaminases. Oral hepatoprotective drugs did not show any significant improvement, and she was admitted to hospital for further diagnosis and treatment. Liver biopsy confirmed IAD. After about 2 wk of ursodeoxycholic acid treatment, serological and histological examination showed a significant response. CONCLUSION: IAD is a manifestation of cholestasis, but also may be an abnormal increase in transaminase in the early stage.

19.
J Nanosci Nanotechnol ; 20(3): 1838-1844, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31492350

RESUMO

Pt/Bi2WO6 composite photocatalysts were prepared by a facile photoreduction method. Pt nanoparticles with an average size of 5-8 nm were successfully deposited on the surface of Bi2WO6 microspheres and the photocatalytic activity of Bi2WO6 was greatly improved by Pt nanoparticles. The photo-induced charge transfer properties of samples were studied by means of surface photovoltage (SPV) and transient photovoltage (TPV) techniques, giving an insight into the intrinsic reasons of the improvement in photocatalytic activity. The SPV and TPV results revealed that the deposited Pt nanoparticles could trap photo-induced electrons and then largely enhance the separation efficiency of photo-induced charge carriers.

20.
Ying Yong Sheng Tai Xue Bao ; 31(9): 2993-3004, 2020 Sep 15.
Artigo em Zh | MEDLINE | ID: mdl-33345500

RESUMO

The khulan (Equus hemionus hemionus) is a representative species in desert, semi-desert and desert steppe in Asia. The estimation of suitable habitat and population density of khulan can provide scientific decision-making basis for the conservation management. We investigated the distribution and population density of khulan in the Mt. Kalamaili Ungulate Nature Reserve in Xinjiang during May-August in 2018 and 2019, using the line transect method. The khulan population density, number and the encounter rate were estimated by the Distance 7.0 software, and through the MaxEnt model analysis and combining environmental variables, we assessed the most suitable habitats and main influencing factors. In total, we recorded 4782 individuals from 718 groups and 363 effective occurrences. Our results showed that the suitable summer habitat covered an area of 6737.5 km2, accounting for 45.4% of the total reserve area and located mainly in the central and eas-tern parts of the reserve. We estimated that the density of the summer khulan population was (0.5±0.1) individuals·km-2 and the total khulan population were (3246±575) individuals in the Mt. Kalamaili Ungulate Nature Reserve. The prediction accuracy of MaxEnt model was relatively high, with an average AUC of 0.890. The results of the Jackknife test showed that the distance to water sources, vegetation type, distance to human interference, distance to national highway G216, altitude, and precipitation of driest areas were the most important factors affecting the habitat suitability for khulan. For improving the protection of the khulan population in this reserve, we suggested strengthen the protection of water sources, adjust the core areas, monitor wildlife passages, and enhance traffic construction.


Assuntos
Altitude , Ecossistema , Animais , Animais Selvagens , Ásia , Humanos , Densidade Demográfica
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