Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 143
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Cell Mol Neurobiol ; 44(1): 43, 2024 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-38703332

RESUMEN

Cell transplantation is a promising treatment option for spinal cord injury (SCI). However, there is no consensus on the choice of carrier scaffolds to host the cells. This study aims to evaluate the efficacy of different material scaffold-mediated cell transplantation in treating SCI in rats. According to PRISMA's principle, Embase, PubMed, Web of Science, and Cochrane databases were searched, and relevant literature was referenced. Only original research on cell transplantation plus natural or synthetic scaffolds in SCI rats was included. Direct and indirect evidence for improving hind limb motor function was pooled through meta-analysis. A subgroup analysis of some factors that may affect the therapeutic effect was conducted to understand the results fully. In total, 25 studies met the inclusion criteria, in which 293 rats received sham surgery, 78 rats received synthetic material scaffolds, and 219 rats received natural materials scaffolds. The network meta-analysis demonstrated that although synthetic scaffolds were slightly inferior to natural scaffolds in terms of restoring motor function in cell transplantation of SCI rats, no statistical differences were observed between the two (MD: -0.35; 95% CI -2.6 to 1.9). Moreover, the subgroup analysis revealed that the type and number of cells may be important factors in therapeutic efficacy (P < 0.01). Natural scaffolds and synthetic scaffolds are equally effective in cell transplantation of SCI rats without significant differences. In the future, the findings need to be validated in multicenter, large-scale, randomized controlled trials in clinical practice. Trial registration: Registration ID CRD42024459674 (PROSPERO).


Asunto(s)
Trasplante de Células , Traumatismos de la Médula Espinal , Andamios del Tejido , Animales , Traumatismos de la Médula Espinal/terapia , Ratas , Andamios del Tejido/química , Trasplante de Células/métodos , Metaanálisis en Red , Resultado del Tratamiento , Recuperación de la Función
2.
Opt Lett ; 48(2): 335-338, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36638451

RESUMEN

Tunable slow and fast light generation in a silicon-on-insulator (SOI) Fano resonator is proposed and experimentally demonstrated. The slow and fast light generation with symmetric and asymmetric coupling conditions of the Fano resonator is theoretically analyzed. Under a slightly imbalanced coupling condition, the two output ports of the Fano resonator could produce a fast light and a slow light, respectively. By utilizing the thermo-optic (TO) effect to change the phase difference of the two optical beams coupled into the resonator, the transition of fast and slow light can be realized at the fixed resonance wavelength. Experimental results show that a slow-to-fast transition (group delay from 0.852 to -1.057 ns) at one resonance wavelength, and a fast-to-slow transition (group delay from -0.22 to 0.867 ns) at another resonance wavelength are realized simultaneously by controlling the microheater to tune the phase difference.

3.
PLoS Comput Biol ; 18(10): e1010594, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36215325

RESUMEN

Advanced volumetric imaging methods and genetically encoded activity indicators have permitted a comprehensive characterization of whole brain activity at single neuron resolution in Caenorhabditis elegans. The constant motion and deformation of the nematode nervous system, however, impose a great challenge for consistent identification of densely packed neurons in a behaving animal. Here, we propose a cascade solution for long-term and rapid recognition of head ganglion neurons in a freely moving C. elegans. First, potential neuronal regions from a stack of fluorescence images are detected by a deep learning algorithm. Second, 2-dimensional neuronal regions are fused into 3-dimensional neuron entities. Third, by exploiting the neuronal density distribution surrounding a neuron and relative positional information between neurons, a multi-class artificial neural network transforms engineered neuronal feature vectors into digital neuronal identities. With a small number of training samples, our bottom-up approach is able to process each volume-1024 × 1024 × 18 in voxels-in less than 1 second and achieves an accuracy of 91% in neuronal detection and above 80% in neuronal tracking over a long video recording. Our work represents a step towards rapid and fully automated algorithms for decoding whole brain activity underlying naturalistic behaviors.


Asunto(s)
Encéfalo , Caenorhabditis elegans , Animales , Caenorhabditis elegans/fisiología , Encéfalo/fisiología , Neuronas/fisiología
4.
J Asian Nat Prod Res ; 25(9): 834-841, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36617869

RESUMEN

A chemical investigation of 95% ethanol extract from the stem and branch of Tripterygium wilfordii has resulted in the isolation and characterization of two new compounds, one neolignan (1) and one phenylalanine derivative (2), as well as four known compounds (3-6). The structures of the new compounds were determined based on extensive spectroscopic analyses. The absolute configuration of compound 1 was defined by X-ray crystallographic analyses and electronic circular dichroism calculation. In addition, compounds 2 and 4-6 exhibited inhibitory effects against NO production in LPS-induced RAW 264.7 macrophages with the IC50 value ranging from 3.51 µM to 30.40 µM.


Asunto(s)
Óxido Nítrico , Tripterygium , Ratones , Animales , Células RAW 264.7 , Tripterygium/química , Hojas de la Planta/química , Macrófagos , Estructura Molecular
5.
J Asian Nat Prod Res ; 25(12): 1184-1190, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37178131

RESUMEN

Two new pregnane glycosides (1 and 2), together with four known ones (3- 6), were isolated from the roots of Cynanchum auriculatum Royle ex Wight (Asclepiadaceae). On the basis of detailed spectroscopic analysis and chemical method, the structures of new compounds were characterized to be metaplexigenin 3-O-ß-D-cymaropyranosyl- (1→4)-α-L-diginopyranosyl-(1→4)-ß-D-cymaropyranoside (1), metaplexigenin 3-O-α-L-diginopyranosyl-(1→4)-ß-D-cymaropyranoside (2). All the isolated compounds (1-6) were tested for their in vitro inhibitory activity against the growth of human colon cancer cell lines HCT-116. Compounds 5 and 6 showed significant cytoxicities with IC50 values of 43.58 µM and 52.21 µM.


Asunto(s)
Cynanchum , Humanos , Cynanchum/química , Raíces de Plantas/química , Pregnanos/farmacología , Pregnanos/química , Glicósidos/farmacología , Glicósidos/química , Estructura Molecular
6.
Int J Mol Sci ; 24(3)2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36769161

RESUMEN

Pancreatic cancer (PC) is one of the most aggressive malignancies. A combination of targeted therapies could increase the therapeutic efficacy in tumors with heterogeneous target expression. Overexpression of the human epidermal growth factor receptor type 3 (HER3) and the epithelial cell adhesion molecule (EpCAM) in up to 40% and 30% of PCs, respectively, is associated with poor prognosis and highlights the relevance of these targets. Designed ankyrin repeat protein (DARPin) Ec1 fused with the low immunogenic bacterial toxin LoPE provides specific and potent cytotoxicity against EpCAM-expressing cancer cells. Here, we investigated whether the co-targeting of HER3 using the monoclonal antibody seribantumab (MM-121) and of EpCAM using Ec1-LoPE would improve the therapeutic efficacy in comparison to the individual agents. Radiolabeled 99mTc(CO)3-Ec1-LoPE showed specific binding with rapid internalization in EpCAM-expressing PC cells. MM-121 did not interfere with the binding of Ec1-LoPE to EpCAM. Evaluation of cytotoxicity indicated synergism between Ec1-LoPE and MM-121 in vitro. An experimental therapy study using Ec1-LoPE and MM-121 in mice bearing EpCAM- and HER3-expressing BxPC3 xenografts demonstrated the feasibility of the therapy. Further development of the co-targeting approach using HER3 and EpCAM could therefore be justified.


Asunto(s)
Proteínas de Repetición de Anquirina Diseñadas , Neoplasias Pancreáticas , Humanos , Animales , Ratones , Molécula de Adhesión Celular Epitelial , Xenoinjertos , Estudios de Factibilidad , Línea Celular Tumoral , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/patología , Modelos Animales de Enfermedad , Ensayos Antitumor por Modelo de Xenoinjerto , Neoplasias Pancreáticas
7.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 54(1): 39-48, 2023 Jan.
Artículo en Zh | MEDLINE | ID: mdl-36647641

RESUMEN

Periodontitis is a chronic oral inflammatory disease with a high incidence in the global population. Periodontal pathogens can colonize and infect multiple human tissues and organs through blood transmission, which is an important risk factor of many systemic diseases. Recently, the correlation between periodontitis and adverse pregnancy outcomes (APOs) has attracted growing research interest. Herein, we systematically reviewed the research progress in the relationship between periodontitis and APOs and summarized reported findings on the pathways and mechanisms by which periodontitis contributes to APOs. We also clarified that intrauterine infection caused by oral pathogens transmitted through blood is an important pathway by which periodontitis interferes with pregnancy. In addition, further research focused on the discovery of more APOs-related oral pathogenic bacteria and their virulence factors, analysis of the interaction between pathogenic bacteria and placental tissue, and pathogenic pathways of oral bacterial invasion of the fetus will promote thorough analysis of the specific molecular mechanism of how periodontitis affects APOs. Furthermore, the validation of the results of human population-based studies through animal/cell experiments and the translation into effective intervention strategies are of great clinical significance to the prevention and control of the occurrence and development of APOs.


Asunto(s)
Periodontitis , Complicaciones del Embarazo , Animales , Embarazo , Femenino , Humanos , Resultado del Embarazo , Placenta , Periodontitis/complicaciones , Periodontitis/microbiología , Factores de Riesgo
8.
Opt Express ; 30(14): 24852-24861, 2022 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-36237029

RESUMEN

We experimentally demonstrate a polarization-insensitive optical filter (PIOF) using polarization rotator-splitters (PRSs) and microring resonators (MRRs) on the silicon-on-insulator (SOI) platform with complementary metal-oxide-semiconductor (CMOS) compatible fabrication process. The PRS consists of a tapered-rib waveguide and an asymmetrical directional coupler (ADC), which realize the polarization rotation and splitting, to ensure the connected MRRs-based optical filter operating at one desired polarization when light with different polarizations are launched into the device. The measured results show that the optical transmission spectra of the device are identical for TE and TM polarization input. The box-like filtering spectra are also achieved with a 3-dB bandwidth of ∼0.15 nm and a high extinction ratio (ER) over 30 dB.

9.
Int J Mol Sci ; 23(18)2022 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-36142633

RESUMEN

Mammals that live in cold climates endure months of exposure to low temperature in the winter. The incidence of respiratory diseases has increased. The goal of this study was to investigate the effects of chronic cold stress on lung inflammatory networks, apoptosis, and mitochondrial function via Yorkshire pig models, as well as the ameliorative effect of glucose as energy supplements. Here, two trials were conducted (chronic cold stress and glucose supplementation). The results showed that chronic cold stress induced obvious inflammatory cell infiltration in the lungs and damaged the lung tissue structure. Compared with the Y-Con group, the expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), high mobility group box 1 (HMGB1), nucleotide-binding domain, and leucine-rich repeat protein 3 (NLRP3), IL-1ß, IL-2, IL-6, and IFN-γ in the lungs of the Y-CS group was enhanced by chronic cold stress (p < 0.05). Moreover, chronic cold stress promoted the expression of the Bax and Mfn2 in lungs of Y-CS group (p < 0.05). Interestingly, dietary glucose supplementation significantly reduced inflammatory cell infiltration in the lungs. Moreover, glucose supplementation inhibited the expression of TLR4, MyD88, HMGB1, NLRP3, IL-1ß, IL-2, IL-6, IFN-γ, and Bax during chronic cold stress. In conclusion, chronic cold stress promoted inflammatory networks, apoptosis, and mitochondrial fusion in the lungs. Dietary glucose supplementation inhibited the inflammatory network during chronic cold stress.


Asunto(s)
Proteína HMGB1 , Receptor Toll-Like 4 , Animales , Respuesta al Choque por Frío , Suplementos Dietéticos , Glucosa/farmacología , Proteína HMGB1/metabolismo , Inflamación , Interleucina-2/metabolismo , Interleucina-6/metabolismo , Pulmón/metabolismo , Mamíferos/metabolismo , Factor 88 de Diferenciación Mieloide/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Nucleótidos/metabolismo , Transducción de Señal , Porcinos , Receptor Toll-Like 4/metabolismo , Proteína X Asociada a bcl-2/metabolismo
10.
Molecules ; 27(19)2022 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-36235020

RESUMEN

Pure organic room-temperature phosphorescence (RTP) materials built upon noncovalent interactions have attracted much attention because of their high efficiency, long lifetime, and stimulus-responsive behavior. However, there are limited reports of noncovalent RTP materials because of the lack of specific design principles and clear mechanisms. Here, we report on a noncovalent material prepared via facile grinding that can emit fluorescence and RTP emission differing from their components' photoluminescent behavior. Exciplex can be formed during the preparation process to act as the minimum emission unit. We found that H-bonds in the RTP system provide restriction to nonradiative transition but also enhance energy transformation and energy level degeneracy in the system. Moreover, water-stimulated photoluminescent ink is produced from the materials to achieve double-encryption application with good resolution.

11.
Mod Pathol ; 34(5): 922-933, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-32973328

RESUMEN

We report 17 cases of sinusoidal large B-cell lymphoma (SLBCL). Clinical, morphologic, immunophenotypic, and molecular features were detected and analyzed. All cases showed an obvious sinusoidal growth pattern, usually associated with residual atrophic lymphoid tissue. All tumors contained large pleomorphic lymphoid cells and one or more prominent nucleoli, with abundant amphophilic cytoplasms; 15/17 cases showed anaplastic morphologic features. The patient age ranged from 43 to 80 years (median 57 years), and 7 males and 10 females were included. Eleven of 15 (73.3%) patients had Ann Arbor stage III or IV disease, and 10/15 (66.6%) patients had an International Prognostic Index (IPI) score ≥3. Immunophenotypically, 16/17 (94.1%) cases displayed a nongerminal center B-cell (non-GCB) immunophenotype. Furthermore, 16/17 (94.1%) cases were positive for CD30, and p53 was expressed in 10/16 (62.5%) cases. In total, 12/14 (85.7%) cases expressed BCL2 and MYC simultaneously (double expression), and 11/14 (78.6%) cases showed PD-L1 positivity (6/11 had a PD-L1 tumor proportion score ≥50%). Cytogenetically, concurrent MYC and BCL2 and/or BCL6 abnormalities (break-apart or extra copy) were detected in 10/15 cases, and 7/13 (53.8%) cases harbored a PD-L1/L2 amplification. TP53 mutation was found in 7/13 (53.8%) cases by Sanger sequencing. Whole-exome and large-panel sequencing results revealed high mutation frequencies of TP53 (4/7), MYD88 (3/7), KMT2D (3/7), CREBBP (3/7), and PIM1 (3/7). Among the 13 patients with SLBCL treated with aggressive chemotherapy regimens, the median overall survival (OS) was 18 months, and the 2-year OS rate was 34.6%. The OS of patients with SLBCL was markedly worse than that of 35 control group patients with common diffuse large B-cell lymphoma (DLBCL) without sinusoidal features (P < 0.001). SLBCL may represent a specific type of DLBCL that has characteristic pathologic features. The cancer is aggressive in most clinical cases, and outcomes are poor. SLBCL and anaplastic DLBCL (A-DLBCL) have many overlapping clinicopathological and molecular features.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biomarcadores de Tumor/genética , Linfoma de Células B/patología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Frecuencia de los Genes , Humanos , Inmunofenotipificación , Linfoma de Células B/tratamiento farmacológico , Linfoma de Células B/genética , Linfoma de Células B/mortalidad , Masculino , Persona de Mediana Edad , Mutación , Estadificación de Neoplasias , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-6/genética , Proteínas Proto-Oncogénicas c-myc/genética , Tasa de Supervivencia , Resultado del Tratamiento , Proteína p53 Supresora de Tumor/genética
12.
J Hum Genet ; 66(5): 543-548, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33177702

RESUMEN

Foveal hypoplasia is the major cause of visual loss. Here we report an isolated foveal hypoplasia patient without nystagmus. It is very rare, and its etiology is not completely understood. Using whole-exome sequencing and foveal hypoplasia-related gene filtering from a family with two generations, we identified a novel variant c.859T>C (p.S287P) and a rare non-frameshift variant c.229_230insGGG (p.Arg77_Glu78insGly) in the tyrosinase (TYR) gene that co-segregated in the affected member of this family. The compound heterozygous variants inherited in the proband were confirmed by Sanger sequencing and predicted from in silico studies to have an effect on protein function. In conclusion, our finding extends the spectrum of TYR variants and supports the important role of TYR in the development of eyes.


Asunto(s)
Enfermedades Hereditarias del Ojo/genética , Fóvea Central/anomalías , Monofenol Monooxigenasa/genética , Mutagénesis Insercional , Mutación Missense , Nistagmo Congénito/genética , Mutación Puntual , Secuencia de Aminoácidos , Angiografía/métodos , Niño , Simulación por Computador , Ojo/embriología , Enfermedades Hereditarias del Ojo/diagnóstico por imagen , Femenino , Fóvea Central/diagnóstico por imagen , Heterocigoto , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Masculino , Modelos Moleculares , Monofenol Monooxigenasa/química , Nistagmo Congénito/diagnóstico por imagen , Linaje , Prolina/química , Conformación Proteica , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad , Tomografía de Coherencia Óptica , Secuenciación del Exoma
13.
Proc Natl Acad Sci U S A ; 115(19): E4493-E4502, 2018 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-29686107

RESUMEN

Descending signals from the brain play critical roles in controlling and modulating locomotion kinematics. In the Caenorhabditis elegans nervous system, descending AVB premotor interneurons exclusively form gap junctions with the B-type motor neurons that execute forward locomotion. We combined genetic analysis, optogenetic manipulation, calcium imaging, and computational modeling to elucidate the function of AVB-B gap junctions during forward locomotion. First, we found that some B-type motor neurons generate rhythmic activity, constituting distributed oscillators. Second, AVB premotor interneurons use their electric inputs to drive bifurcation of B-type motor neuron dynamics, triggering their transition from stationary to oscillatory activity. Third, proprioceptive couplings between neighboring B-type motor neurons entrain the frequency of body oscillators, forcing coherent bending wave propagation. Despite substantial anatomical differences between the motor circuits of C. elegans and higher model organisms, converging principles govern coordinated locomotion.


Asunto(s)
Animales Modificados Genéticamente/metabolismo , Caenorhabditis elegans/fisiología , Uniones Comunicantes/fisiología , Interneuronas/fisiología , Locomoción , Actividad Motora/fisiología , Neuronas Motoras/fisiología , Animales , Animales Modificados Genéticamente/genética , Conducta Animal , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Calcio/metabolismo , Interneuronas/citología , Neuronas Motoras/citología , Optogenética
14.
J Asian Nat Prod Res ; 23(12): 1140-1147, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33502251

RESUMEN

A pair of new enantiomeric trinorsesquiterpenes, (+)-genpenterpene A (1a) and (-)-genpenterpene A (1b), together with seven known compounds (2-8), were isolated from the aerial parts of Justicia gendarussa Burm.f.. All of these known compounds were isolated from this plant for the first time. Racemic genpenterpene A was separated by chiral HPLC column. Their chemical structures were elucidated based on extensive spectroscopic analysis, single crystal X-ray diffraction, and ECD calculations. (+)-genpenterpene A (1a) exhibited potent inhibitory effect against nitric oxide production in lipopolysaccharide-activated RAW 264.7 mouse macrophage cells with an IC50 value of 9.54 ± 1.02 µM.


Asunto(s)
Género Justicia , Animales , Lipopolisacáridos/farmacología , Ratones , Estructura Molecular , Componentes Aéreos de las Plantas , Células RAW 264.7
15.
J Asian Nat Prod Res ; 23(1): 82-88, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31888376

RESUMEN

Barbaram (1), a neolactam together with other five known compunds (2-6) was isolated from the EtOAc-soluble fraction of an EtOH extract of the root and stem of Lycium barbarum by using silica gel, Sephadex LH-20 column chromatography and semi-preparative RP-C18 HPLC. Based on HR-TOF-MS, NMR spectral data, quantum chemistry ECD calculations and referencing to the data reported earlier, the structures of these compounds (1-6) were determined, specially including the absolute configuration of the neolactam (1). Compounds 2 and 4 showed significant anti-inflammatory activity in LPS-induced RAW 264.7 macrophages with the IC50 values of 8.98 ± 0.57 µM, 6.68 ± 0.77 µM.


Asunto(s)
Lycium , Antiinflamatorios , Cromatografía Líquida de Alta Presión , Espectroscopía de Resonancia Magnética , Estructura Molecular
16.
J Craniofac Surg ; 31(1): e53-e57, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31609953

RESUMEN

Postoperative remote intracranial hemorrhage (rICH) secondary to craniotomy surgery is an extremely rare but catastrophic complication. The present study aimed to investigate the incidence and the possible pathophysiological mechanism of rICH after brain tumor surgery. The clinical data from 9 rICH cases among 4588 patients undergoing brain tumor surgery were collected retrospectively. Remote intracranial hemorrhage occurred in 9 cases, including 6 cases of remote epidural hemorrhage (rEDH), 2 cases of remote subdural hemorrhage (rSDH), and 1 case of remote cerebellar hemorrhage (rCBH). Among the 9 cases, 2 were males and 7 were females, with an age range of 22 to 63 years (mean of 44.3 years). The incidence of rICH in the patients with ventricular system opening/drainage (4/258) was much higher than the patients without ventricular system opening/drainage (5/4330), and the difference was statistically significant (P < 0.01). Hematoma evacuation was performed in 7 patients with serious neurological status or massive hematoma. The outcome for most of the rICH cases was good, and the Glasgow outcome scale scores of 4-5 were found in 8 cases with a 3-month-long follow-up. Our results suggest that brain tumor surgery with ventricular system opening/drainage was more susceptible to rICH. Paying particlular attention to gradual reduction of intracranial pressure and avoiding excessive loss of cerebrospinal fluid may aid to prevent the occurrence of rICH. The authors suggest that a high index of suspicion, a prompt diagnosis, and emergent management is of vital importance to achieve good prognosis for rICH patients secondary to brain tumor surgery.


Asunto(s)
Neoplasias Encefálicas/cirugía , Craneotomía/efectos adversos , Hemorragias Intracraneales/etiología , Adulto , Drenaje , Femenino , Escala de Consecuencias de Glasgow , Humanos , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Estudios Retrospectivos , Adulto Joven
17.
Sensors (Basel) ; 20(4)2020 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-32102356

RESUMEN

The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)°, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.

18.
Int J Mol Sci ; 21(9)2020 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32392820

RESUMEN

Epithelial cell adhesion molecule (EpCAM) is overexpressed in 55%-75% of ovarian carcinomas (OC). EpCAM might be used as a target for a treatment of disseminated OC. Designed ankyrin repeats protein (DARPin) Ec1 is a small (18 kDa) protein, which binds to EpCAM with subnanomolar affinity. We tested a hypothesis that Ec1 labeled with a non-residualizing label might serve as a companion imaging diagnostic for stratification of patients for EpCAM-targeting therapy. Ec1 was labeled with 125I using N-succinimidyl-para-iodobenzoate. Binding affinity, specificity, and cellular processing of [125I]I-PIB-Ec1 were evaluated using SKOV-3 and OVCAR-3 ovarian carcinoma cell lines. Biodistribution and tumor-targeting properties of [125I]I-PIB-Ec1 were studied in Balb/c nu/nu mice bearing SKOV-3 and OVCAR-3 xenografts. EpCAM-negative Ramos lymphoma xenografts served as specificity control. Binding of [125I]I-PIB-Ec1 to ovarian carcinoma cell lines was highly specific and had affinity in picomolar range. Slow internalization of [125I]I-PIB-Ec1 by OC cells confirmed utility of non-residualizing label for in vivo imaging. [125I]I-PIB-Ec1 provided 6 h after injection tumor-to-blood ratios of 30 ± 11 and 48 ± 12 for OVCAR-3 and SKOV-3 xenografts, respectively, and high contrast to other organs. Tumor targeting was highly specific. Saturation of tumor uptake at a high dose of Ec1 in SKOV-3 model provided a rationale for dose selection in further studies using therapeutic conjugates of Ec1 for targeted therapy. In conclusion, [125I]I-PIB-Ec1 is a promising agent for visualizing EpCAM expression in OC.


Asunto(s)
Molécula de Adhesión Celular Epitelial/metabolismo , Radioisótopos de Yodo/química , Imagen Molecular/métodos , Neoplasias Ováricas/diagnóstico por imagen , Proteínas Recombinantes de Fusión/administración & dosificación , Animales , Línea Celular Tumoral , Estudios de Factibilidad , Femenino , Humanos , Ratones , Ratones Desnudos , Terapia Molecular Dirigida , Trasplante de Neoplasias , Neoplasias Ováricas/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/farmacocinética , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón Único , Distribución Tisular
19.
Int J Mol Sci ; 21(4)2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-32075258

RESUMEN

Human epidermal growth factor receptor type 3 (HER3) is an emerging therapeutic target in several malignancies. To select potential responders to HER3-targeted therapy, radionuclide molecular imaging of HER3 expression using affibody molecules could be performed. Due to physiological expression of HER3 in normal organs, high imaging contrast remains challenging. Due to slow internalization of affibody molecules by cancer cells, we hypothesized that labeling (HE)3-ZHER3:08698-DOTAGA affibody molecule with non-residualizing [125I]-N-succinimidyl-4-iodobenzoate (PIB) label would improve the tumor-to-normal organs ratios compared to previously reported residualizing radiometal labels. The [125I]I-PIB-(HE)3-ZHER3:08698-DOTAGA was compared side-by-side with [111In]In-(HE)3-ZHER3:08698-DOTAGA. Both conjugates demonstrated specific high-affinity binding to HER3-expressing BxPC-3 and DU145 cancer cells. Biodistribution in mice bearing BxPC-3 xenografts at 4 and 24 h pi showed faster clearance of the [125I]I-PIB label compared to the indium-111 label from most tissues, except blood. This resulted in higher tumor-to-organ ratios in HER3-expressing organs for [125I]I-PIB-(HE)3-ZHER3:08698-DOTAGA at 4 h, providing the tumor-to-liver ratio of 2.4 ± 0.3. The tumor uptake of both conjugates was specific, however, it was lower for the [125I]I-PIB label. In conclusion, the use of non-residualizing [125I]I-PIB label for HER3-targeting affibody molecule provided higher tumor-to-liver ratio than the indium-111 label, however, further improvement in tumor uptake and retention is needed.


Asunto(s)
Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Radioisótopos/farmacología , Receptor ErbB-3/aislamiento & purificación , Distribución Tisular/efectos de la radiación , Animales , Línea Celular Tumoral , Xenoinjertos , Humanos , Radioisótopos de Indio/química , Radioisótopos de Yodo/química , Marcaje Isotópico , Ratones , Imagen Molecular/métodos , Radiofármacos/farmacología , Receptor ErbB-3/genética
20.
Molecules ; 25(19)2020 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-32998229

RESUMEN

Albumin binding domain-Derived Affinity ProTeins (ADAPTs) are small (5 kDa) engineered scaffold proteins that are promising targeting agents for radionuclide-based imaging. A recent clinical study has demonstrated that radiolabeled ADAPTs can efficiently visualize human epidermal growth factor receptor 2 (HER2) expression in breast cancer using SPECT imaging. However, the use of ADAPTs directly labeled with radiometals for targeted radionuclide therapy is limited by their high reabsorption and prolonged retention of activity in kidneys. In this study, we investigated whether a co-injection of lysine or gelofusin, commonly used for reduction of renal uptake of radiolabeled peptides in clinics, would reduce the renal uptake of [99mTc]Tc(CO)3-ADAPT6 in NMRI mice. In order to better understand the mechanism behind the reabsorption of [99mTc]Tc(CO)3-ADAPT6, we included several compounds that act on various parts of the reabsorption system in kidneys. Administration of gelofusine, lysine, probenecid, furosemide, mannitol, or colchicine did not change the uptake of [99mTc]Tc(CO)3-ADAPT6 in kidneys. Sodium maleate reduced the uptake of [99mTc]Tc(CO)3-ADAPT6 to ca. 25% of the uptake in the control, a high dose of fructose (50 mmol/kg) reduced the uptake by ca. two-fold. However, a lower dose (20 mmol/kg) had no effect. These results indicate that common clinical strategies are not effective for reduction of kidney uptake of [99mTc]Tc(CO)3-ADAPT6 and that other strategies for reduction of activity uptake or retention in kidneys should be investigated for ADAPT6.


Asunto(s)
Riñón/metabolismo , Proteínas/farmacología , Radiofármacos/farmacología , Animales , Autorradiografía , Cromatografía Líquida de Alta Presión , Cromatografía de Fase Inversa , Femenino , Ratones , Proteínas/administración & dosificación , Proteínas/metabolismo , Radiofármacos/administración & dosificación , Distribución Tisular/efectos de los fármacos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA