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1.
Artigo em Inglês | MEDLINE | ID: mdl-34665724

RESUMO

In recent years, the manufacturing process of lead zinc niobate-lead titanate [Pb(Zn1/3Nb2/3)O3-PbTiO3, also called PZN-PT] has been enhanced with improvements in size, consistency and a suitable compromise between piezoelectric properties and phase transition temperature, which means that it is possible to obtain PZN-PT single crystals in sufficient size for performance characterization studies and batch manufacturing to produce high-performance medical ultrasonic transducers. This paper mainly focuses on the development of the 64-element phased array ultrasonic transducer based on novel large-size PZN-PT piezoelectric single crystals. The composition of the single crystal was chosen as PZN-5.5 %PT. The designed center frequency of the phased array is 3.0 MHz, which is suitable for cardiac ultrasound imaging. The array elements were spaced at a 0.254 mm pitch, and interconnected through a custom-designed flexible circuit. Double matching layers with a light backing structure were applied in the transducer fabrication process to improve the performance of the array. The test results of the developed phased array showed a center frequency of 3.0 MHz, and an average -6 dB fractional bandwidth of 72%. In the vicinity of the center frequency, the two-way insertion loss (IL) was about -46 dB, while a crosstalk between the adjacent elements was less than -31 dB. The wire phantom can be distinctly imaged with the phased array and the axial and lateral resolutions were measured to be 660 and 1299 µm, respectively. The image of a standard phantom was acquired to present the imaging performance of the transducer. The final results indicate that the transducer arrays based on novel large-size PZN-PT single crystals are quite promising for use in medical ultrasound imaging applications.

2.
Shanghai Kou Qiang Yi Xue ; 30(3): 247-252, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34476439

RESUMO

PURPOSE: To investigate the effects of different hypoxic concentrations on biological characteristics of human dental pulp stem cells in vitro. METHODS: Impacted mandibular third molars were extracted from healthy individuals, and the dental pulp stem cells were cultured by tissue block enzyme digestion. Cells cultured under the conditions of 3%, 5% and 21% oxygen concentration for 7 days were set as 3% hypoxia group, 5% hypoxia group, and 21% nomoxia group, respectively. Flow cytometry was used to detect cell surface markers, cell cycle and apoptosis. Cell proliferation was measured by CCK-8 method. Transwell chamber assay was used to detect migration ability. Statistical analysis was completed by SPSS 20.0 software package. RESULTS: The expression rates of CD44, CD29 and D73 of the subculture cells were 97.25%, 99.36% and 99.60%, respectively. The proliferation ability of dental pulp stem cells was the strongest in 5% hypoxia group, and weakest in 3% hypoxia group, with significant difference(P<0.05). The apoptosis rate had no significant difference among various concentrations of oxygen(P>0.05). Compared with 21% nomoxia group, the proportion of dental pulp stem cells in G1 phase was significantly lower than that in 3% hypoxia group and 5% hypoxia group(P<0.05), and cell in S phase was significantly higher than that in 3% hypoxia group and 5% hypoxia group(P<0.05). The migration ability was the strongest in 3% hypoxia group, and weakest in 21% nomoxia group, with significant difference(P<0.05). CONCLUSIONS: Different concentrations of hypoxia have great influence on the morphology, proliferation, migration and cell cycle of human dental pulp stem cells in vitro with little impact on cell apoptosis.


Assuntos
Polpa Dentária , Células-Tronco , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Humanos , Hipóxia
3.
Artigo em Inglês | MEDLINE | ID: mdl-34550882

RESUMO

Cardiovascular disease has become one of the leading causes of death in China, accounting for 45.5% of all deaths in rural areas and 43.16% in urban areas. Hence, its early diagnosis is important. With the development of intravascular imaging technology, the intravascular ultrasound (IVUS) is widely used. The available commercial mechanical rotary side-looking IVUS transducers are driven by external motors that use long flexible shafts to transmit the rotation. However, when the transducer passes through a long-curved blood vessel, it easily causes the non-uniform rotation distortion (NURD) of the image. A catheter which contains a distal motor and NaCl solution is presented in this study as an attempt to solve such issues. The NaCl solution is used to connect the transducer and micromotor so that the motor can directly drive the transducer to rotate and acquire the information of the blood vessel. The results showed that the center frequency and -6 dB fraction bandwidth of the single element were 47 MHz and 98%, respectively. The side-looking IVUS catheter consists of a distal motor, with speed stability and high resolution, has potential to diagnose cardiovascular disease. This novel structure can decrease the dimension at the top of the catheter, and reduce the risks of the clinical diagnosis.

4.
Cell Metab ; 33(8): 1640-1654.e8, 2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34107313

RESUMO

Obesity is characterized by the excessive accumulation of the white adipose tissue (WAT), but healthy expansion of WAT via adipocyte hyperplasia can offset the negative metabolic effects of obesity. Thus, identification of novel adipogenesis regulators that promote hyperplasia may lead to effective therapies for obesity-induced metabolic disorders. Using transcriptomic approaches, we identified transmembrane BAX inhibitor motif-containing 1 (TMBIM1) as an inhibitor of adipogenesis. Gain or loss of function of TMBIM1 in preadipocytes inhibited or promoted adipogenesis, respectively. In vivo, in response to caloric excess, adipocyte precursor (AP)-specific Tmbim1 knockout (KO) mice displayed WAT hyperplasia and improved systemic metabolic health, while overexpression of Tmbim1 in transgenic mice showed the opposite effects. Moreover, mature adipocyte-specific Tmbim1 KO did not affect WAT cellularity or nutrient homeostasis. Mechanistically, TMBIM1 binds to and promotes the autoubiquitination and degradation of NEDD4, which is an E3 ligase that stabilizes PPARγ. Our data show that TMBIM1 is a potent repressor of adipogenesis and a potential therapeutic target for obesity-related metabolic disease.

5.
Ultrasonics ; 116: 106478, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34174743

RESUMO

Keratoconus, a serious corneal disorder, often causes highly irregular astigmatism and different degrees of visual impairment. Riboflavin/UVA corneal collagen cross-linking(CXL) is currently approved for effective treatment of keratoconus by enhancing the mechanical strength of collagen fibers in the cornea. However, few methods are capable of quantitatively and non-destructively assessing the mechanical properties of the cornea before and after CXL treatments. This study developed a corneal viscoelasticity imaging method based on comb-push ultrasound shear elastography (CUSE) and implemented this method on a Verasonics™ Vantage 256 ultrasound open system with a high-frequency linear array ultrasound transducer. Push beams were generated by three teeth each consisting of 10 elements (working frequency = 10.41 MHz) for inducing Lamb wave propagation in the cornea, and then the system immediately switched to the plane wave imaging mode using 60 elements in the middle (working frequency = 18 MHz). This method can provide a high-resolution 2D Lamb wave velocity image overlapping with a B-mode image as well as quantitative viscoelasticity estimation according to experimentally obtained phase velocity dispersion of Lamb waves. The validation experiments were performed on ex vivo porcine corneas, and the accuracy of elasticity estimation was verified by a tensile test. The results showed that the shear elasticity increased and the viscosity decreased after CXL treatment. The shear elasticity results (reported as mean ±â€¯standard deviation) of one control group with no CXL treatment and three CXL-treated groups named as 10 min, 30 min, and 60 min groups according to UV irradiation time were 14.62 ±â€¯3.38 kPa, 49.47 ±â€¯3.63 kPa, 116.54 ±â€¯23.99 kPa, and 197.89 ±â€¯39.64 kPa, respectively, which was in agreement with the results of tensile tests. The ultrasound safety measurement indicated that this method could have acceptable safety, but further to ocular tissue and vision function. The study demonstrated the possibility of using a commercial ultrasound system to obtain high-resolution images of corneal mechanical properties as well as the ability to quantify changes induced by CXL treatment. Therefore, the proposed method could serve as a helpful tool in the studies related in corneal biomechanics.

6.
Biomed Eng Online ; 20(1): 45, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941179

RESUMO

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming one of the most common liver diseases. Ultrasound elastography has been used for the diagnosis of NAFLD. However, clinical research on steatosis by elastography technology has mainly focused on steatosis with fibrosis or non-alcoholic steatohepatitis (NASH), while steatosis without fibrosis has been poorly studied. Moreover, the relationship between liver viscoelasticity and steatosis grade is not clear. In this study, we evaluated the degree of liver steatosis in a simple steatosis rat model using shear wave elastography (SWE). RESULTS: The viscoelasticity values of 69 rats with hepatic steatosis were measured quantitatively by SWE in vivo and validated by a dynamic mechanical analysis (DMA) test. Pathological sections were used to determine the steatosis grade for each rat. The results showed that the elasticity values µ obtained by the two methods followed the same trend, and µ is significantly correlated with liver steatosis. The Pearson's correlation coefficients indicate that [Formula: see text] obtained by SWE is positively linear correlated with DMA (r = 0.628, p = 7.85 × 10-9). However, the viscosity values [Formula: see text] obtained by SWE were relatively independent of those obtained by DMA with a correlation coefficient of - 0.01. The combined Voigt elasticity measurements have high validity in the prediction of steatosis (S0 vs. S1-S4), with an AUROC of 0.755 (95% CI 0.6175-0.8925, p < 0.01) and the optimal cutoff value was 2.08 kPa with a sensitivity of 78% and specificity of 63%. CONCLUSION: SWE might have the feasibility to be introduced as an auxiliary technique for NAFLD patients in clinical settings. However, the viscosity results measured by SWE and DMA are significantly different, because the two methods work in different frequency bands.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Técnicas de Imagem por Elasticidade , Fígado , Masculino , Ratos , Viscosidade
8.
Phys Med Biol ; 66(9)2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33725674

RESUMO

Magneto-acousto-electrical tomography (MAET) is designed to produce conductivity images with high spatial resolution for a conducting object. In a previous study, for an irregular conductor, transverse scanning and rotational methods with a focus transducer were combined to collect complete electrical information. This kind of method, however, is time-consuming because of the transverse scanning procedure. In this study, we proposed a novel imaging method based on plane ultrasound waves and a new aspect of projection in rotational MAET. In the proposed method, we achieved the projection in each rotation angle by using plane waves rather than mechanical scanning of the focus waves along the transverse direction. Thus, the imaging time was significantly saved. To verify the proposed method, we derived a measurement formula containing a lateral integration, which built the relationship between the measurement formula and the projection under each rotation angle. Next, we constructed two different numerical models to compute magneto-acousto-electrical signals by using a finite element method and reconstructed the corresponding conductivity parameter images based on a filtered back-projection algorithm. Then, simulated signals under different signal-to-ratios (6, 20, 40, and 60 dB) were generated to test the performance of the proposed algorithm. To improve the image quality, we further analysed the influence of the filters and the frequency scaling factors embedded in the filtered back-projection algorithm. Moreover, we computed the L2norm of the error in case of different frequency scaling factors and measurement noises. Finally, we conducted a phantom experiment with a 64-element linear phased array transducer (center frequency of 2.7 MHz) and reconstructed the conductivity parameter images of the circular phantom with an elliptical hole. The experimental results demonstrated the feasibility and time-efficiency of the proposed rapid rotational MAET.


Assuntos
Tomografia , Acústica , Algoritmos , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Fatores de Tempo , Tomografia Computadorizada por Raios X
9.
Front Genet ; 12: 608629, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732283

RESUMO

Non-obstructive azoospermia (NOA) is one of the most important causes of male infertility. It is mainly characterized by the absence of sperm in semen repeatedly or the number of sperm is small and not fully developed. At present, its pathogenesis remains largely unknown. The goal of this study is to identify hub genes that might affect biomarkers related to spermatogenesis. Using the clinically significant transcriptome and single-cell sequencing data sets on the Gene Expression Omnibus (GEO) database, we identified candidate hub genes related to spermatogenesis. Based on them, we performed Gene Ontology (GO) functional enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analyses, protein-protein interaction (PPI) network analysis, principal component analysis (PCA), cell cluster analysis, and pseudo-chronological analysis. We identified a total of 430 differentially expressed genes, of which three have not been reported related to spermatogenesis (C22orf23, TSACC, and TTC25), and the expression of these three hub genes was different in each type of sperm cells. The results of the pseudo-chronological analysis of the three hub genes indicated that TTC25 was in a low expression state during the whole process of sperm development, while the expression of C22orf23 had two fluctuations in the differentiating spermatogonia and late primary spermatocyte stages, and TSACC showed an upward trend from the spermatogonial stem cell stage to the spermatogenesis stage. Our research found that the three hub genes were different in the trajectory of sperm development, indicating that they might play important roles in different sperm cells. This result is of great significance for revealing the pathogenic mechanism of NOA and further research.

10.
IEEE Trans Cybern ; 51(1): 233-246, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31567112

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disease with an irreversible and progressive process. To understand the brain functions and identify the biomarkers of AD and early stages of the disease [also known as, mild cognitive impairment (MCI)], it is crucial to build the brain functional connectivity network (BFCN) using resting-state functional magnetic resonance imaging (rs-fMRI). Existing methods have been mainly developed using only a single time-point rs-fMRI data for classification. In fact, multiple time-point data is more effective than a single time-point data in diagnosing brain diseases by monitoring the disease progression patterns using longitudinal analysis. In this article, we utilize multiple rs-fMRI time-point to identify early MCI (EMCI) and late MCI (LMCI), by integrating the fused sparse network (FSN) model with parameter-free centralized (PFC) learning. Specifically, we first construct the FSN framework by building multiple time-point BFCNs. The multitask learning via PFC is then leveraged for longitudinal analysis of EMCI and LMCI. Accordingly, we can jointly learn the multiple time-point features constructed from the BFCN model. The proposed PFC method can automatically balance the contributions of different time-point information via learned specific and common features. Finally, the selected multiple time-point features are fused by a similarity network fusion (SNF) method. Our proposed method is evaluated on the public AD neuroimaging initiative phase-2 (ADNI-2) database. The experimental results demonstrate that our method can achieve quite promising performance and outperform the state-of-the-art methods.


Assuntos
Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Redes Neurais de Computação , Doença de Alzheimer/diagnóstico por imagem , Progressão da Doença , Humanos , Imageamento por Ressonância Magnética , Máquina de Vetores de Suporte
11.
Ultrasonics ; 110: 106272, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33065465

RESUMO

Sonodynamic therapy (SDT) is a promising modality for cancer treatment. Sinoporphyrin sodium (DVDMS), purified from Photofrin II, shows great potential in SDT evidenced by growing studies. The purpose of the current study was to investigate the antitumor effect of SDT combined with DVDMS on human glioblastoma (U87 MG) cell line in vitro. The cellular uptake of DVDMS was investigated by confocal microscopy and IVIS spectrum imaging system. In addition, DVDMS toxicity and anti-tumor effect of SDT were assessed by flow cytometry. The generation of intracellular reactive oxygen species (ROS) was determined using DCFH-DA staining. Simultaneously, fluorescence microscopy was performed to access the destabilization of mitochondrial membrane potential (MMP). The results showed that DVDMS could easily enter the cells and accumulated in the cytoplasm, especially the mitochondria. And the intracellular DVDMS increased with incubation time or concentrations. The results also showed remarkable cytotoxicity of DVDMS-mediated SDT (center frequency: 0.970 MHz; peak-rarefactional pressure: 0.52-MPa; acoustic power: 0.32 W; pulse repetition frequency: 1 Hz; duty cycle: 1-30%; duration: 3 min) on U87 MG cells, while DVDMS alone was non-toxic to the cells. In comparison with the control group, the SDT-treated group showed significant generation of intracellular ROS and loss of MMP at 1 h post-treatment. These results indicated that DVDMS-mediated SDT could induce great cytotoxicity in U87 MG cells via the production of ROS and showed potentials in the treatment for glioblastoma.


Assuntos
Antineoplásicos/farmacologia , Glioblastoma/terapia , Porfirinas/farmacologia , Terapia por Ultrassom/métodos , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Desenho de Equipamento , Humanos , Técnicas In Vitro , Potencial da Membrana Mitocondrial , Necrose , Espécies Reativas de Oxigênio/metabolismo
12.
Theranostics ; 10(25): 11794-11819, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33052247

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disease manifested by cognitive impairment. As a unique approach to open the blood-brain barrier (BBB) noninvasively and temporarily, a growing number of studies showed that low-intensity focused ultrasound in combination with microbubbles (FUS/MB), in the absence of therapeutic agents, is capable of ameliorating amyloid or tau pathology, concurrent with improving memory deficits of AD animal models. However, the effects of FUS/MB on both the two pathologies simultaneously, as well as the memory behaviors, have not been reported so far. Methods: In this study, female triple transgenic AD (3×Tg-AD) mice at eight months of age with both amyloid-ß (Aß) deposits and tau phosphorylation were treated by repeated FUS/MB in the unilateral hippocampus twice per week for six weeks. The memory behaviors were investigated by the Y maze, the Morris water maze and the step-down passive avoidance test following repeated FUS/MB treatments. Afterwards, the involvement of Aß and tau pathology were assessed by immunohistochemical analysis. Neuronal health and phagocytosis of Aß deposits by microglia in the hippocampus were examined by confocal microscopy. Further, hippocampal proteomic alterations were analyzed by employing two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with mass spectrometry. Results: The three independent memory tasks were indicative of evident learning and memory impairments in eight-month-old 3×Tg-AD mice, which developed intraneuronal Aß, extracellular diffuse Aß deposits and phosphorylated tau in the hippocampus and amygdala. Following repeated FUS/MB treatments, significant improvement in learning and memory ability of the 3×Tg-AD mice was achieved. Amelioration in both Aß deposits and phosphorylated tau in the sonicated hemisphere was induced in FUS/MB-treated 3×Tg-AD mice. Albeit without increase in neuron density, enhancement in axonal neurofilaments emerged from the FUS/MB treatment. Confocal microscopy revealed activated microglia engulfing Aß deposits in the FUS/MB-treated hippocampus. Further, proteomic analysis revealed 20 differentially expressed proteins, associated with glycolysis, neuron projection, mitochondrial pathways, metabolic process and ubiquitin binding etc., in the hippocampus between FUS/MB-treated and sham-treated 3×Tg-AD mice. Conclusions: Our findings reinforce the positive therapeutic effects on AD models with both Aß and tau pathology induced by FUS/MB-mediated BBB opening, further supporting the potential of this treatment regime for clinical applications.


Assuntos
Doença de Alzheimer/terapia , Hipocampo/patologia , Transtornos da Memória/terapia , Microbolhas/uso terapêutico , Terapia por Ultrassom/métodos , Doença de Alzheimer/complicações , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos da radiação , Modelos Animais de Doenças , Feminino , Hipocampo/efeitos da radiação , Humanos , Transtornos da Memória/diagnóstico , Transtornos da Memória/genética , Transtornos da Memória/patologia , Camundongos , Camundongos Transgênicos , Presenilina-1/genética , Presenilina-1/metabolismo , Proteômica , Ondas Ultrassônicas , Proteínas tau/genética , Proteínas tau/metabolismo
13.
Math Biosci Eng ; 17(4): 2864-2880, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32987504

RESUMO

Magneto-Acousto-Electrical Tomography (MAET) is a novel multi-physics imaging method, which promises to offer a unique biophysical property of tissue electrical impedance with the additional benefit of excellent spatial resolution of the ultrasonic imaging. It opens the potential for early diagnosis of cancer by revealing changes of dielectric characteristics. However, direct MAET is unable to image the irregularly-shaped lesions fully due to the dependence on the angle between conductivity boundary and ultrasound beam direction. In this paper, a numerical simulation of multi-angle MAET is presented for an improved image reconstruction for MAET in order to discern irregularly-shaped tumors in different positions. The results show that the conductivity boundary interfaces are invisible in single angle B-mode reconstructed image, wherever the ultrasound beam and conductivity boundary are nearly parallel. When the multi-angle scanning was adopted, the image reconstructed with image rotation method reproduced the original object pattern. Furthermore, the relationship between reconstruction error and the number of angles was also discussed. It is found that 12 angles would be necessary to achieve nearly the optimal reconstruction. Finally, reconstructed images in L2 norm of the error with the measurement noise are presented.


Assuntos
Acústica , Algoritmos , Impedância Elétrica , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Tomografia , Tomografia Computadorizada por Raios X
14.
Theranostics ; 10(23): 10448-10465, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32929359

RESUMO

Rationale: Insufficient penetration and accumulation of theranostic payloads in solid tumors greatly challenge the clinical translation of cancer nanomedicines. To address this challenge, we synthesized natural melanin-cored and doxorubicin-loaded perfluoropentane nanodroplets with good biocompatibility and self-assembling ability. Methods: We used an opto-acoustic synergistic irradiation (OASI) method that was effective at lower energy levels than ultrasound- or laser-only irradiation to safely vaporize the nanodroplets and to cavitate the generated microbubbles for mechanically enhancing intratumoral delivery. The delivered melanin and doxorubicin inside the tumors mediated secondary chemo-photothermal therapy under laser irradiation to fully kill cancer cells. Results: In vivo animal experiments demonstrated direct mechanical disruption of tumor structures (H&E staining), enhanced intratumoral penetration of melanin (photoacoustic imaging), and efficient intratumoral accumulation of doxorubicin (fluorescent imaging). Anti-tumor experiments demonstrated that the nanodroplets combined with OASI treatment and subsequent laser irradiation could efficiently eliminate melanoma tumors. Conclusion: Melanin-cored and doxorubicin-loaded perfluoropentane nanodroplets hold great promise for translational sono-chemo-photothermal cancer therapy.


Assuntos
Doxorrubicina/administração & dosagem , Portadores de Fármacos/efeitos da radiação , Microbolhas/uso terapêutico , Neoplasias/terapia , Nanomedicina Teranóstica/métodos , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/química , Feminino , Fluorcarbonetos/química , Humanos , Hipertermia Induzida/métodos , Terapia a Laser/métodos , Melaninas/química , Melaninas/efeitos da radiação , Camundongos , Nanopartículas/química , Nanopartículas/efeitos da radiação , Neoplasias/diagnóstico por imagem , Neoplasias/patologia , Técnicas Fotoacústicas/métodos , Fotoquimioterapia/métodos , Terapia por Ultrassom/métodos , Volatilização/efeitos da radiação , Ensaios Antitumorais Modelo de Xenoenxerto
15.
BMC Microbiol ; 20(1): 197, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32631309

RESUMO

BACKGROUND: Salmonella is one of the main causative agents of diarrhea which results in substantial disease burden. To determine the prevalence, serotype distribution, and antimicrobial resistance profiles of clinical Salmonella isolates in Shenzhen, a 6-year surveillance study was conducted. RESULTS: A total of 297 (5.7%) Salmonella strains were isolated from stool samples from 5239 patients. Among the 42 serotypes identified, serotype Typhimurium was the most common one which represented 39.7% of the isolates (118), followed by serotype Enteritidis (71, 23.9%), London (12, 4.0%), 4, 5, 12: i: - (11, 3.7%), and Senftenberg (8, 2.7%). A high frequency of resistance was found in ampicillin (70.6%), piperacillin (64.5%), tetracycline (63.5%), and streptomycin (54.3%). Resistance to ampicillin and tetracycline was observed in 95.3% of S. Typhimurium isolates; and nalidixic acid in 93.1% of S. Enteritidis isolates. Resistance to 5 or more antimicrobial agents was found in 78.8% of S. Typhimurium and 69.0% of S. Enteritidis isolates. A decreased susceptibility to ciprofloxacin and levofloxacin was associated with amino acid alteration in gyrA gene. Point mutations without amino acid changes were seen in gyrB, parC, and parE genes. CONCLUSIONS: A broad range of serotypes are responsible for Salmonellosis in Shenzhen, with Enteritidis and Typhimurium being the most common serotypes. The high level of antibiotic resistance is of public health significance and ongoing monitoring combined with rational use of antibiotics are recommended. Point mutations in gyrA gene might play an important role in the resistance to fluoroquinolones.


Assuntos
Antibacterianos/farmacologia , Diarreia/microbiologia , Farmacorresistência Bacteriana , Infecções por Salmonella/epidemiologia , Salmonella/classificação , Adolescente , Adulto , Criança , Pré-Escolar , China/epidemiologia , Diarreia/epidemiologia , Diarreia/imunologia , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Filogenia , Vigilância da População , Prevalência , Salmonella/efeitos dos fármacos , Salmonella/imunologia , Salmonella/isolamento & purificação , Infecções por Salmonella/imunologia , Sorogrupo , Adulto Jovem
16.
Med Image Anal ; 64: 101716, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32492581

RESUMO

Skin lesion segmentation from dermoscopy images is a fundamental yet challenging task in the computer-aided skin diagnosis system due to the large variations in terms of their views and scales of lesion areas. We propose a novel and effective generative adversarial network (GAN) to meet these challenges. Specifically, this network architecture integrates two modules: a skip connection and dense convolution U-Net (UNet-SCDC) based segmentation module and a dual discrimination (DD) module. While the UNet-SCDC module uses dense dilated convolution blocks to generate a deep representation that preserves fine-grained information, the DD module makes use of two discriminators to jointly decide whether the input of the discriminators is real or fake. While one discriminator, with a traditional adversarial loss, focuses on the differences at the boundaries of the generated segmentation masks and the ground truths, the other examines the contextual environment of target object in the original image using a conditional discriminative loss. We integrate these two modules and train the proposed GAN in an end-to-end manner. The proposed GAN is evaluated on the public International Skin Imaging Collaboration (ISIC) Skin Lesion Challenge Datasets of 2017 and 2018. Extensive experimental results demonstrate that the proposed network achieves superior segmentation performance to state-of-the-art methods.


Assuntos
Diagnóstico por Computador , Processamento de Imagem Assistida por Computador , Humanos
17.
Biomed Eng Online ; 19(1): 52, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32552718

RESUMO

BACKGROUND: Colorectal cancer is the third leading cause of cancer-related deaths worldwide. Sonodynamic therapy (SDT) is an emerging cancer therapy, and in contrast to photodynamic therapy, could non-invasively reach deep-seated tissues and locally activates a sonosensitizer preferentially accumulated in the tumor area to produce cytotoxicity effects. In comparison with traditional treatments, SDT may serve as an alternative strategy for human colon cancer treatment. Here, we investigated the sonodynamic effect using sinoporphyrin sodium (DVDMS) as a novel sonosensitizer on human colon cancer cells in vitro. RESULTS: The absorption spectra of DVDMS revealed maximum absorption at 363 nm wavelength and emission peak at 635 nm. Confocal microscopy images revealed the DVDMS was primarily localized in the cytoplasm, while no evident signal was detected within the nuclei. Flow cytometry analysis showed rapid intracellular uptake of DVDMS by two types of human colon cancer cells (HCT116 and RKO). Cell viability of HCT116 was tolerant with the concentration of DVDMS up to 20 µg/mL, while the case of RKO was 5 µg/mL. In comparison with the control group, the SDT-treated groups of these two types of human colon cancer cells showed significant increase in cellular apoptosis and necrosis ratio. Increased intracellular reactive oxygen species (ROS) production was detected, indicating the involvement of ROS in mediating SDT effects. CONCLUSION: DVDMS results an effective sonosensitizer for the ultrasound-mediated cancer cell killing, and its anticancer effect seems to rely on its ability to produce ROS under ultrasound exposure.


Assuntos
Neoplasias do Colo/patologia , Neoplasias do Colo/terapia , Porfirinas/farmacologia , Terapia por Ultrassom/métodos , Apoptose/efeitos dos fármacos , Transporte Biológico , Células HCT116 , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Necrose/induzido quimicamente , Porfirinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
18.
Front Microbiol ; 11: 736, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32373106

RESUMO

Autophagy is a primary protective process that involves removing damaged organelles or dysfunctional proteins in eukaryotes. The autophagy pathway not only maintains cellular homeostasis, but also modulates the host's cellular response to pathogen infection. Several studies proved that autophagy plays a dominant role in plant fitness and immunity. As intracellular parasites, the replication and spread of viruses entirely rely upon the molecular machinery of the host cell, including the autophagy process. Plant viruses severely affect crop yields and quality. During infection, complex interactions occur between viral proteins and host factors in relation to plant defense and virus counter-defense. An increasing number of studies demonstrated that plants use autophagy to eliminate and inhibit viruses; some viruses were shown to manipulate the process of autophagy to promote their own replication and survival in plant cells. In this review, we summarize recent advances in plant autophagy, with an emphasis on the role of autophagy in plant virus infection.

19.
Med Phys ; 47(8): 3533-3544, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32343838

RESUMO

PURPOSE: Magnetoacoustic tomography with magnetic induction (MAT-MI) is a technique that utilizes the acoustic signals induced by magnetic stimulation to reconstruct the electrical impedance distribution in biological tissues. Most algorithms ignored the fact that acoustic properties in human tissues are heterogeneous, which lead to distortion and blurring of small reconstructed objects. In this study, a novel algorithm is proposed for exact reconstruction of the sound source distribution in acoustic heterogeneous tissues. METHODS: Based on the ring transducer array, we develop an algorithm which combines algebraic reconstruction technique (ART) and time reversal method. Different to existing reconstruction methods, the ultrasonic transmission tomography (UTT) and the MAT-MI can be completed in same system, which decreases the system complexity. The sound velocity distribution is reconstructed with the ART so that the propagation time of the magnetoacoustic signals in the heterogeneous tissue is corrected. And then, the sound source image is reconstructed based on the time reversal method from new sound pressure data. Both numerical simulations and phantom experiments are established to validate the proposed method. RESULTS: Compared with the results without consideration of the variation on acoustic speed, sound sources reconstructed by our method are more consistent with the model in terms of size and shape. CONCLUSIONS: The novel algorithm can be used to reconstruct the high-accuracy image of MAT-MI sound source in the sound velocity inhomogeneous media. In addition, this method is applicable to scenarios that the prior knowledge of the imaging targets is unknown. The signal acquisition time of MAT-MI in acoustically heterogeneity media is greatly reduced due to the introduction of ring transducer array into the imaging system. Therefore, our method will promote the application of MAT-MI in noninvasive early diagnosis of tumor for preclinical study.


Assuntos
Algoritmos , Tomografia , Acústica , Humanos , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Transdutores
20.
J Cell Biochem ; 121(11): 4397-4405, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32031285

RESUMO

Ovarian cancer (OC) is one of the deadliest malignancies of the female reproductive system. The present study focused on the role of Nucleolar spindle-associated protein 1 (NuSAP1) in OC. Relative expression of NuSAP1 was detected in OC tissues as well as cells. After knocking down NuSAP1 with lentivirus-mediated shRNA and verifying the knockdown efficiency via quantitative real-time polymerase chain reaction and Western blot assays, the cell proliferation, apoptosis, and cell cycle were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony formation, and flow cytometry, respectively. Transwell assay was conducted to detect the migration and invasion of OC cells. It was showed that NuSAP1 was abundantly expressed in OC tissues and cell lines. After knocking down NuSAP1 in OC cells, in addition to significantly inhibiting proliferation and colony forming ability, it also promotes apoptosis and affects cell cycle distribution. Moreover, cells in the shNuSAP1 group showed significantly suppressed migration and invasion ability compared with that in the shCtrl group. In conclusion, NuSAP1 may act as an oncogenic factor in OC and therefore might serve as an indicator for prognosis and therapeutic target for OC treatment.


Assuntos
Biomarcadores Tumorais/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas Associadas aos Microtúbulos/metabolismo , Neoplasias Ovarianas/patologia , Apoptose , Biomarcadores Tumorais/genética , Movimento Celular , Proliferação de Células , Feminino , Humanos , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/genética , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Prognóstico , RNA Interferente Pequeno/genética , Células Tumorais Cultivadas
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