Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 505
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Virol ; 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31694940

RESUMO

RNA interference (RNAi) is a conserved antiviral immune defence in eukaryotes, and numerous viruses have been found to encode viral suppressors of RNAi (VSRs) to counteract antiviral RNAi. Alphaviruses are a large group of positive-stranded RNA viruses that maintain their transmission and life cycles in both mosquitoes and mammals. However, there is little knowledge about how alphaviruses antagonize RNAi in both host organisms. In this study, we identified that Semliki Forest virus (SFV) capsid protein can efficiently suppress RNAi in both insect and mammalian cells by sequestrating dsRNA and siRNA. More importantly, when the VSR activity of SFV capsid was inactivated by reverse genetics, the resulting VSR-deficient SFV mutant showed severe replication defects in mammalian cells, which could be rescued by blocking the RNAi pathway. Besides, capsid protein of Sindbis virus (SINV) also inhibited RNAi in cells. Together, our findings show that SFV uses capsid protein as VSR to antagonize RNAi in infected mammalian cells, and this mechanism is probably used by other alphaviruses, which shed new light on the knowledge of SFV and alphavirus.Importance Alphaviruses are a genus of positive-stranded RNA viruses and include numerous important human pathogens, such as Chikungunya virus, Ross River virus, Western equine encephalitis virus, etc, which create the emerging and re-emerging public health threat worldwide. RNA interference (RNAi) is one of the most important antiviral mechanisms in plants and insects. Accumulating evidence has provided strong support for the existence of antiviral RNAi in mammals. In response to antiviral RNAi, viruses have evolved to encode viral suppressors of RNAi (VSRs) to antagonize the RNAi pathway. It is unclear if alphaviruses encode VSRs that can suppress antiviral RNAi during their infection in mammals. In this study, we first uncovered that capsid protein encoded by Semliki Forest virus (SFV), a prototypic alphavirus, had a potent VSR activity that can antagonize antiviral RNAi in the context of SFV infection in mammalian cells, and this mechanism is probably used by other alphaviruses.

2.
Small ; : e1903723, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31577385

RESUMO

As promising cathode materials, iron-based phosphate compounds have attracted wide attention for sodium-ion batteries due to their low cost and safety. Among them, sodium iron fluorophosphate (Na2 FePO4 F) is widely noted due to its layered structure and high operating voltage compared with NaFePO4 . Here, a mesoporous Na2 FePO4 F@C (M-NFPF@C) composite derived from mesoporous FePO4 is synthesized through a facile ball-milling combined calcination method. Benefiting from the mesoporous structure and highly conductive carbon, the M-NFPF@C material exhibits a high reversible capacity of 114 mAh g-1 at 0.1 C, excellent rate capability (42 mAh g-1 at 10 C), and good cycling performance (55% retention after 600 cycles at 5 C). The high plateau capacity obtained (>90% of total capacity) not only shows high electrochemical reversibility of the as-prepared M-NFPF@C but also provides high energy density, which mainly originates from its mesoporous structure derived from the mesoporous FePO4 precursor. The M-NFPF@C serves as a promising cathode material with high performance and low cost for sodium-ion batteries.

5.
Medicine (Baltimore) ; 98(39): e17144, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574815

RESUMO

RATIONALE: Benign fibrous histiocytoma with pleural involvement in spinal region is a highly unusual disease with no standard curative managements yet. The objective of this study is to report an extremely rare case of a giant benign fibrous histiocytoma with pleural involvement in spinal region successfully operated by posterior spinal surgery. The management of these unique cases has yet to be well-documented. PATIENT CONCERNS: A 23-year-old man presented with a 2-month history of continuous and progressive back pain. A giant, expanding lesion of the T7 vertebral and paraspinal region with pleural involvement was identified. DIAGNOSES: Computed tomography scan and magnetic resonance imaging of spine showed expanding lesion of the T7 vertebral and paraspinal region involving the right thoracic cavity, which presented as a solid tumor. Postoperative pathology confirmed the diagnosis of thoracic benign fibrous histiocytoma. INTERVENTIONS: The patient underwent thoracic spinal canal decompression, complete tumor resection, pleural defect repair, and T4 to T10 internal fixation procedure via a posterior approach. OUTCOMES: The patient's symptom improved significantly after the surgery, and the postoperative period was uneventful at the 2-year follow-up visit. There were no complications associated with the operation during the follow-up period. LESSONS: In summary, the tumor's clinical features, imaging results, and pathological characteristics are unique. Combined efforts of specialists from orthopedics, thoracic surgery, neurosurgery, pathology, and medical oncology led to the successful diagnosis and management of this patient. Giant benign fibrous histiocytoma with pleural involvement in spinal region, although rare, should be part of the differential diagnosis when the patient presents with back pain and radiculopathy. We recommend the posterior or 1-stage anterior-posterior combined approach for complete resection of the giant thoracic benign fibrous histiocytoma when the tumor has caused severe symptoms or neurological deficits.


Assuntos
Descompressão Cirúrgica/métodos , Histiocitoma Fibroso Benigno/cirurgia , Neoplasias Pleurais/cirurgia , Neoplasias da Coluna Vertebral/cirurgia , Adulto , Histiocitoma Fibroso Benigno/patologia , Humanos , Masculino , Cavidade Pleural/patologia , Cavidade Pleural/cirurgia , Neoplasias Pleurais/patologia , Neoplasias da Coluna Vertebral/patologia , Vértebras Torácicas/patologia , Vértebras Torácicas/cirurgia
6.
Medicine (Baltimore) ; 98(39): e17145, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574816

RESUMO

RATIONALE: Paragangliomas are rare neuroendocrine tumors that originate in specialized cells derived from the neural crest with metastasis to the thoracic spine being among the rarest forms. Here, we are presenting a detailed analysis of a case of malignant paraganglioma in the thoracic spinal region in a 14-year-old boy. Our focus is to emphasize the importance of considering malignant paraganglioma as a diagnosis and guiding the perioperative management upon surgical treatment. The management of these unique cases has yet to be well-documented. PATIENT CONCERNS: A 14-year-old boy presented with a 5-month history of continuous and progressive elevated blood pressure and back pain. The patient, who had been diagnosed of malignant paraganglioma in the left posterior mediastinum for 3 months, received surgical resection of paraganglioma in the left posterior mediastinum, which had involved the left intervertebral foramen of T4. However, the tumor was not completely resected during the first operation. DIAGNOSES: Magnetic resonance imaging of spine and positron emission tomography-computed tomography showed spinal cord compression secondary to the epidural component of the T4 mass, with increased marrow infiltration of the left T4 intervertebral foramen, which was difficult to be removed. Postoperative pathology confirmed the diagnosis of spinal involvement of malignant paraganglioma. INTERVENTIONS: The patient underwent biopsy and percutaneous vertebroplasty of T4 and paravertebral lesions, and needle-track cement augmentation via a posterior approach. OUTCOMES: The patient's neurological deficits improved significantly after the surgery, and the postoperative period was uneventful at the 10-month follow-up visit. There were no other complications associated with the operation during the follow-up period. LESSONS: Combined efforts of specialists from orthopedics, neurosurgery, thoracic surgery, and medical oncology led to the successful diagnosis and management of this patient. Malignant paraganglioma of thoracic spine, although rare, should be part of the differential diagnosis when the patient has a history of paraganglioma and presents with back pain and radiculopathy. We recommend the posterior approach for spinal decompression of the malignant paraganglioma when the tumor has caused neurological deficits. Osteoplasty by cement augmentation is also a good choice for surgical treatment. However, we need to take the potential risk of complications in bone cement applications into full consideration.


Assuntos
Neoplasias do Mediastino/cirurgia , Procedimentos Neurocirúrgicos/métodos , Procedimentos Ortopédicos/métodos , Paraganglioma/cirurgia , Neoplasias da Coluna Vertebral/cirurgia , Adolescente , Descompressão Cirúrgica , Humanos , Masculino , Neoplasias do Mediastino/patologia , Paraganglioma/patologia , Neoplasias da Coluna Vertebral/patologia , Vértebras Torácicas/patologia , Vértebras Torácicas/cirurgia , Vertebroplastia/métodos
7.
Bioconjug Chem ; 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31644261

RESUMO

The progression of hepatic fibrosis can lead to cirrhosis and hepatic failure, but the development of antifibrotic drugs have faced the challenges of poor effectiveness and targeted specificity. Herein, a theranostic strategy was carried to encapsulate a natural medicine (Quercetin, QR) into hepatitis B core (HBc) protein nanocages (NCs) for imaging and targeted treatment of hepatic fibrosis. It was noted that nanoparticles (RGD-HBc/QR) with surface-displayed RGD targeting ligand exhibit a rather high selectivity toward activated HSCs via the binding affinity with integrin αvß3, and an efficient inhibition of proliferation and activation of hepatic stellate cells (HSCs) in vitro and in vivo. Once encapsulated in quercetin-gadolinium complex and/or labeled with the NIR fluorescent probes (Cy5.5), the resulting nanoparticles (RGD-HBc/QGd) show great potential as NIR fluorescent and magnetic resonance imaging contrast agents for hepatic fibrosis in vivo. Therefore, the multifunctional integrin-targeted nanoparticles could selectively deliver QR to the activated HSCs, and may provide an effective antifibrotic theranostic strategy.

8.
Appl Opt ; 58(20): 5568-5574, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31504029

RESUMO

An essential issue for the low-noise system application of the fiber optic gyroscope (FOG) is to reduce its noise level. The relative intensity noise (RIN) of the light source is the dominant noise of the FOG when the light power on the detector reaches a certain level. The noise subtraction method is effective for RIN reduction and easy to implement in a FOG. This paper theoretically analyzes the factors that influence the result of the method and deduces the function to calculate the noise suppression ratio that can be achieved. A method that uses an optimum filter design based on the Wiener filter in the reference detector signal is proposed to improve the subtraction result. A FOG system is set up to test the feasibility of the method. The experiment results meet with the theoretical analysis, and by using the Wiener filter, the achieved noise subtraction factor reaches the limitation that restrains the optical system and detection circuit.

9.
Sensors (Basel) ; 19(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31489880

RESUMO

The stable alignment and transmission of free space optical communication (FSO) is susceptible to internal dynamics and external disturbances. In this paper, a virtual dual-loop feedback control (VDFC) with model-construction linear extended state observer (MCLESO), which is applied to the fast tip-tilt mirror platform to enhance the disturbance suppression ability (DSA) for FSO. MCLESO, which is modified on a classical linear extended state observer by introducing the available model information, is shown to use the input and output signal data of the system to observe total disturbances, including internal dynamics and external disturbance. Since the position and velocity signals are both observed only with the optoelectronic target detector and MCLESO, the controllers of the dual-loop feedback control (DFC) system are employed directly. This method has a more accurate control performance after model construction, which enhances the DSA of the tip-tilt mirror control system in low and medium frequency. It is also beneficial to miniaturization and cost saving by not using velocity sensors. Both simulations and experiments validate the effectiveness of the proposed method in the tip-tilt mirror control system under the condition of disturbance.

10.
Environ Pollut ; 254(Pt A): 112962, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31394348

RESUMO

Soil is a fundamental carrier to support for human living and development and has been polluted seriously by heavy metals. This fact highlights the urgency to realize soil heavy metal pollution prevention through soil heavy metals contamination status assessment and root cause analysis. The previous research tends to focus status assessment and source identification without consideration of economic aspect. This study realized the systematic analysis from status assessment, sources identification and economic-environmental cost-benefits analysis in the Yangtze River basin. Through the spatial difference comparison among the provinces of upper, middle and lower in the Yangtze River basin, it revealed that anthropogenic influence is the main reason caused the current Cd contamination in Yangtze River basin. An interesting finding is that the human caused Cd concentration contribution amount is nearly the same between upstream and downstream which is all about 0.1 mg/kg, while they have quite different economic scale. It indicated that due to the difference of the scale and structure of local economy, and the level of cleaner production and pollution treatment, some regions could own high economic-benefits and low environmental cost, which it is opposite in other regions. The geographic location and natural resources is the root cause to form the environmental cost-economic benefits difference among regions. The convenient traffic promoted downstream to develop large amount and high quality of economy. The natural mineral resources promoted midstream to develop resources based economy. The poor condition of traffic and natural resources has restricted the development of Qinghai province, and made it has the highest Cd pollution intensity. The results would provide effective economic management measures for better soil quality and sustainable development goals achievement.

11.
Postgrad Med J ; 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31371461
12.
QJM ; 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31385589
13.
Dis Markers ; 2019: 6270187, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396294

RESUMO

The ratio of soluble fms-like tyrosine kinase-1 to placental growth factor (sFlt-1/PlGF) is elevated and proved to be useful in preeclampsia (PE) diagnosis. Its value in differential diagnosis with other pregnancy complications and prediction of pregnancy duration has yet to be clarified in Chinese population. We retrospectively analyzed 118 singleton pregnancies with suspected or diagnosed PE at the Peking Union Medical College Hospital (PUMCH) in China. Among these, 62 pregnancies were diagnosed as PE (48 early onsets and 14 late onsets, with 39 and 5 severe PE, respectively), 12 gestational hypertension (GH), 15 chronic hypertension (chrHTN), 16 autoimmune diseases, and 13 pregnancies with uncomplicated proteinuria. And 76 normal pregnancies were included as control. The results showed (1) the sFlt-1/PlGF ratio in early onset PE subgroup was significantly higher than that in GH, chrHTN, and control groups; the sFlt-1/PlGF ratio in late onset PE subgroup was significantly higher than that in chrHTN and control groups, but similar as GH group; the sFlt-1/PlGF ratio was similar among GH, chrHTN, and control groups. (2) The sFlt-1/PlGF ratio was significantly increased in the PE group compared with autoimmune disease and uncomplicated proteinuria pregnancies. (3) By ROC curve analysis, the cutoff value of the sFlt-1/PlGF ratio was less than 21.5 to rule out PE and higher than 97.2 to confirm the diagnosis of PE. (4) The sFlt-1/PlGF ratio was higher in PE pregnancies delivering within 7 days than those more than 7 days, either in early onset PE or severe PE. In conclusion, we show that maternal sFlt-1/PlGF ratio is an efficient biomarker in the diagnosis and differential diagnosis of PE. This ratio can be used to predict the timing of delivery for PE pregnancies.

14.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1126-1127: 121722, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31401453

RESUMO

This study established a simple and rapid method for simultaneous determination of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in human serum by high performance liquid chromatography coupled with electron spray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF/MS). A simple pretreatment procedure of protein precipitation by acetonitrile coupled with liquid-liquid extraction by n-hexane was employed for extraction and purification. The purified samples were separated by a PFP chromatographic column. This method could effectively eliminate the matrix effect by lipids and other matrix substances in serum samples with less time and solvent consuming. 76 congener groups of SCCPs and MCCPs with C10-C17 and Cl5-Cl13 were quantified by their [M-H]- ions. Method detection limit (MDL) were 1.0-8.0 ng mL-1 for ∑SCCPs and ∑MCCPs. Recoveries were 98.4 ±â€¯4.42%, 98.8 ±â€¯3.96% and 90.7 ±â€¯2.79% for SCCPs and 93.1 ±â€¯6.67%, 108 ±â€¯1.21% and 90.8 ±â€¯3.78% for MCCPs at spiking concentrations of 20, 50 and 200 ng·mL-1, respectively. The relative standard deviations (RSDs) of intra- and inter-day variations were 1.41% and 9.84% for SCCPs, and 4.23% and 6.26% for MCCPs. The suitability of the developed method was demonstrated through the application to analysis of SCCPs and MCCPs in human serum samples.

15.
Ying Yong Sheng Tai Xue Bao ; 30(7): 2345-2351, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31418238

RESUMO

Clubroot, caused by the soil-borne obligate pathogen Plasmodiophora brassicae, is one of the most severe disease in cruciferous crops. Previous studies showed that when oilseed rape was planted after soybean (namely soybean-oilseed rotation), the incidence and severity of clubroot of oilseed rape could be significantly reduced, compared with that with oilseed rape-oilseed rape conti-nuous cropping. Therefore, the soybean-oilseed rape rotation is a good way to suppress clubroot of oilseed rape. In this study, we compared the rhizosphere microbiome of soybean and oilseed rape rhizosphere soil collected from the field by 16S rRNA (for identification of prokaryotes) and the internal transcribed spacer (ITS) (for identification of fungi) sequencing. The results showed that both soybean and oilseed rape rhizosphere soils had Proteobacteria, Bacteroidetes, Acidobacteria, Actinobacteria, Ascomycota, Zygomycota, Basidiomycota and Chytridiomycota. Many microbial genera (e.g., Flavobacterium, Sphingomonas, Bacillus, Streptomyces, Pseudomonas, Trichoderma and Coniothyrium) with activities of biological control and plant growth promotion were more abundant in soybean rhizosphere soil than in the oilseed rape rhizosphere soil. The abundance of plant pathogenic bacteria and fungi was higher in the oilseed rape rhizosphere soil than in the soybean rhizosphere soil. Moreover, the soybean rhizosphere soil was enriched with Rhizobium, Bradyrhizobium (both for nitrogen fixation), and arbuscular mycorrhizal fungus (Glomus). These results indicated that soybean rhizosphere soil could promote the growth and proliferation of beneficial microorga-nisms, but inhibit that of plant pathogens. Our results provide evidence for explanation of the effectiveness of soybean-oilseed rape rotation to control clubroot of oilseed rape and provide potential bio-control resources for clubroot prevention.


Assuntos
Microbiota , Rizosfera , Microbiologia do Solo , Brassica rapa/crescimento & desenvolvimento , Brassica rapa/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala , RNA Ribossômico 16S , Soja/crescimento & desenvolvimento , Soja/microbiologia
17.
Medicine (Baltimore) ; 98(35): e16990, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31464948

RESUMO

RATIONALE: Giant thoracic chordoma is a highly unusual disease with no standard curative managements yet. The objective of this study is to report a very rare case of giant thoracic chordoma successfully operated by combination of thoracoscopic surgery together with posterior spinal surgery. The management of these unique cases has yet to be well-documented. PATIENT CONCERNS: A 64-year-old man presented with a 4-month history of continuous and progressive back pain. The patient, who had been diagnosed of sacral chordoma for 2 years, received surgical treatment of posterior sacral tumor resection and instrumentation. A lytic, expanding lesion of the T5 and T6 vertebral and paraspinal region with mild epidural spinal cord compression was identified. DIAGNOSIS: MRI of spine and PET/CT showed spinal cord compression secondary to the epidural component of the T5 and T6 mass, with increased metastatic marrow infiltration of the left T5 and T6 vertebral and paravertebral region, which presented as a solid tumor. Postoperative pathology confirmed the diagnosis of thoracic chordoma. INTERVENTIONS: The patient underwent 1-stage thoracoscopic release of vertebral and paravertebral tumors, posterior resection of T5-T6 vertebral and paravertebral tumors, T4-T7 spinal canal decompression, and T2-T9 pedicle screw fixation procedure via a posterior approach. OUTCOMES: The patient's neurological deficits improved significantly after the surgery, and the postoperative period was uneventful at the 3-month and 6-month follow-up visit. There were no other complications associated with the operation during the follow-up period. LESSONS: Taken together, the lesion's clinical features, imaging results, and pathological characteristics are unique. Combined efforts of specialists from orthopedics, thoracic surgery, neurosurgery, and medical oncology led to the successful diagnosis and management of this patient. Giant thoracic chordoma, although rare, should be part of the differential diagnosis when the patient has a history of sacral chordoma and presents with back pain and radiculopathy. We recommend the posterior approach for spinal decompression of the giant thoracic chordoma when the tumor has caused neurological deficits. One-stage thoracoscopic release or resection of vertebral and paravertebral tumor is also a good choice for surgical treatment.


Assuntos
Cordoma/cirurgia , Neoplasias da Coluna Vertebral/cirurgia , Procedimentos Cirúrgicos Operatórios/métodos , Vértebras Torácicas/cirurgia , Cordoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Procedimentos Ortopédicos/métodos , Neoplasias da Coluna Vertebral/patologia , Toracoscopia/métodos
18.
Oxid Med Cell Longev ; 2019: 6869350, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31428228

RESUMO

Our previous study has demonstrated the effects of aqueous extract of lily bulb in alleviating menopause-related psychiatric symptoms in ovariectomized (OVX) mice. This study sought to further investigate the psychotropic effects of total polysaccharides of lily bulb (TPLB) against anxiety, depression, and cognitive deterioration and the underlying mechanisms in OVX mice using behavioral, neurochemical, molecular, and proteomic approaches in comparison with estrogen therapy. While TPLB and estradiol showed similar effects in reducing OVX-induced anxiety, depression, and cognitive impairment, the psychotropic effects of TPLB were more closely associated with the predominant activation of estrogen receptors (ERs) and regulation of brain regional neurotransmitters and neurotrophins with minor effects on the uterus. Estradiol had similar potencies in binding affinity at ERα and ERß, which caused widespread genetic and epigenetic effects. In contrast, TPLB displayed a higher affinity at ERß than ERα, triggering the specific Ras/Akt/ERK/CREB signaling pathway without affecting any epigenetic activity. TPLB additionally modulated multiple proteins associated with mitochondrial oxidative stress, but estradiol did not. These results indicate that TPLB has comparable efficacy in reducing menopause-associated neuropsychological symptoms with a better safety profile compared to estrogen therapy. We suggest that TPLB could serve as a novel agent for menopause syndrome.

20.
Am J Pathol ; 189(10): 2019-2035, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323189

RESUMO

Obesity is associated with adipose inflammation, defined by macrophages encircling dead adipocytes, as well as extracellular matrix (ECM) remodeling and increased risk of breast cancer. Whether ECM affects macrophage phenotype in obesity is uncertain. A better understanding of this relationship could be strategically important to reduce cancer risk or improve outcomes in the obese. Using clinical samples, computational approaches, and in vitro decellularized ECM models, this study quantified the relative abundance of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages in human breast adipose tissue, determined molecular similarities between obesity and tumor-associated macrophages, and assessed the regulatory effect of obese versus lean ECM on macrophage phenotype. Our results suggest that breast adipose tissue contains more M2- than M1-biased macrophages across all body mass index categories. Obesity further increased M2-biased macrophages but did not affect M1-biased macrophage density. Gene Set Enrichment Analysis suggested that breast tissue macrophages from obese versus lean women are more similar to tumor-associated macrophages. These changes positively correlated with adipose tissue interstitial fibrosis, and in vitro experiments indicated that obese ECM directly stimulates M2-biased macrophage functions. However, mammographic density cannot be used as a clinical indicator of these changes. Collectively, these data suggest that obesity-associated interstitial fibrosis promotes a macrophage phenotype similar to tumor-associated macrophages, which may contribute to the link between obesity and breast cancer.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA