Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros

Base de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Int J Mol Sci ; 24(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37373510

RESUMO

The diagnosis of liquid and solid biopsies by different instruments makes the clinic loading difficult in many aspects. Given the compositions of magnetic particles (MPs) with diverse characterizations and the innovative acoustic type of vibration sample magnetometer (VSM), the versatile, accessible magnetic diagnosis platform was proposed to meet clinical demands, such as low loading for multiple biopsies. In liquid biopsies of alpha-fetoprotein (AFP) standard solutions and subject serums, molecular concentration was analyzed from saturation magnetization by the soft type of Fe3O4 MPs with AFP bioprobe coating. In the phantom mixture simulated as bounded MPs in tissue, the bounded MPs was evaluated from the area of the hysteresis loop by hard type of cobalt MPs without bio-probes coating. Not only a calibration curve was founded for many hepatic cell carcinoma stages, but also microscale images verified the Ms increase due to magnetic protein clusters, etc. Hence, its wide populations in clinics could be expected.


Assuntos
Neoplasias Hepáticas , alfa-Fetoproteínas , Humanos , Magnetismo , Neoplasias Hepáticas/diagnóstico , Fenômenos Magnéticos , Biópsia
2.
Biomed Eng Online ; 21(1): 38, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715781

RESUMO

BACKGROUND: Although the powerful clinical effects of radiofrequency and microwave ablation have been established, such ablation is associated with several limitations, including a small ablation size, a long ablation time, the few treatment positioning, and biosafety risks. To overcome these limitations, biosafe and efficient magnetic ablation was achieved in this study by using biocompatible liquid gallium as an ablation medium and a contrast medium for imaging. RESULTS: Magnetic fields with a frequency (f) lower than 200 kHz and an amplitude (H) × f value lower than 5.0 × 109 Am-1 s-1 were generated using the proposed method. These fields could generate an ablation size of 3 cm in rat liver lobes under a temperature of approximately 300 °C and a time of 20 s. The results of this study indicate that biomedical gallium can be used as a contrast medium for the positioning of gallium injections and the evaluation of ablated tissue around a target site. Liquid gallium can be used as an ablation medium and imaging contrast medium because of its stable retention in normal tissue for at least 3 days. Besides, the high anticancer potential of gallium ions was inferred from the self-degradation of 100 µL of liquid gallium after around 21 days of immersion in acidic solutions. CONCLUSIONS: The rapid wireless ablation of large or multiple lesions was achieved through the simple multi-injection of liquid gallium. This approach can replace the currently favoured procedure involving the use of multiple ablation probes, which is associated with limited benefits and several side effects. METHODS: Magnetic ablation was confirmed to be highly efficient by the consistent results obtained in the simulation and in vitro tests of gallium and iron oxide as well as the electromagnetic specifics and thermotherapy performance comparison detailed in this study Ultrasound imaging, X-ray imaging, and magnetic resonance imaging were found to be compatible with the proposed magnetic ablation method. Self-degradation analysis was conducted by mixing liquid gallium in acidic solutions with a pH of approximately 5-7 (to imitate a tumour-containing microenvironment). X-ray diffraction was used to identify the gallium oxides produced by degraded gallium ions.


Assuntos
Técnicas de Ablação , Ablação por Cateter , Gálio , Animais , Gálio/farmacologia , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Ratos , Ultrassonografia
3.
Sensors (Basel) ; 22(22)2022 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-36433573

RESUMO

The objective of the proposed human-machine cooperation (HMC) workstation is to both rapidly detect calcium-based fish bones in masses of minced fish floss and visually guide operators in approaching and removing the detected fish bones by hand based on the detection of fingernails or plastic-based gloves. Because vibration is a separation mechanism that can prevent absorption or scattering in thick fish floss for UV fluorescence detection, the design of the HMC workstation included a vibration unit together with an optical box and display screens. The system was tested with commonly used fish (swordfish, salmon, tuna, and cod) representing various cooking conditions (raw meat, steam-cooked meat, and fish floss), their bones, and contaminating materials such as derived from gloves made of various types of plastic (polyvinylchloride, emulsion, and rubber) commonly used in the removal of fish bones. These aspects were each investigated using the spectrum analyzer and the optical box to obtain and analyze the fluorescence spectra and images. The filter was mounted on a charge-coupled device, and its transmission-wavelength window was based on the characteristic band for fish bones observed in the spectra. Gray-level AI algorithm was utilized to generate white marker rectangles. The vibration unit supports two mechanisms of air and downstream separation to improve the imaging screening of fish bones inside the considerable flow of fish floss. Notably, under 310 nm ultraviolet B (UVB) excitation, the fluorescence peaks of the raw fillets, steam-cooked meat, and fish floss were observed at for bands at longer wavelengths (500-600 nm), whereas those of the calcium and plastic materials occurred in shorter wavelength bands (400-500 nm). Perfect accuracy of 100% was achieved with the detection of 20 fish bones in 2 kg of fish floss, and the long test time of around 10-12 min results from the manual removal of these fish bones.


Assuntos
Cálcio , Vibração , Animais , Humanos , Fluorescência , Vapor , Peixes , Tecnologia , Plásticos
4.
Sensors (Basel) ; 18(4)2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29601532

RESUMO

An alternating-current magnetosusceptometer of antibody-functionalized magnetic nanoparticles (MNPs) was developed for immunomagnetic reduction (IMR). A high-sensitivity, high-critical-temperature superconducting quantum interference device was used in the magnetosusceptometer. Minute levels of biomarkers of early-stage neurodegeneration diseases were detectable in serum, but measuring each biomarker required approximately 4 h. Hence, an eight-channel platform was developed in this study to fit minimal screening requirements for Alzheimer's disease. Two consistent results were measured for three biomarkers, namely Aß40, Aß42, and tau protein, per human specimen. This paper presents the instrument configuration as well as critical characteristics, such as the low noise level variations among channels, a high signal-to-noise ratio, and the coefficient of variation for the biomarkers' IMR values. The instrument's ultrahigh sensitivity levels for the three biomarkers and the substantially shorter total measurement time in comparison with the previous single- and four-channels platforms were also demonstrated in this study. Thus, the eight-channel instrument may serve as a powerful tool for clinical high-throughput screening of Alzheimer's disease.


Assuntos
Nanopartículas de Magnetita , Doença de Alzheimer , Peptídeos beta-Amiloides , Biomarcadores , Humanos , Imunoensaio , Magnetismo , Proteínas tau
5.
J Neurol Neurosurg Psychiatry ; 88(10): 818-824, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28550072

RESUMO

OBJECTIVE: α-Synuclein is critical to the pathogenesis of Parkinson's disease (PD). Few studies examined the plasma levels of α-synuclein due to the exceptionally low level of α-synuclein in plasma compared with cerebrospinal fluid. We aimed to investigate plasma α-synuclein in patients with PD of different disease severity. METHODS: There were total 114 participants, including 80 patients with PD and 34 controls, in the study. Participants received a complete evaluation of motor and non-motor symptoms, including cognitive function. We applied immunomagnetic reduction-based immunoassay to measure plasma levels of α-synuclein. RESULTS: Plasma levels of α-synuclein were significantly higher in patients with PD compared with controls (median: 1.56 pg/mL, 95% CI 1.02 to 1.98 pg/mL vs 0.02 pg/mL, 95% CI 0.01 to 0.03 pg/mL; p<0.0001). Although there was a significant increase in plasma α-synuclein levels in PD patients with a higher Hoehn-Yahr (H-Y) stage, there was no correlation with motor symptom severity, as assessed by Unified Parkinson's Disease Rating Scale part III scores, after confounders (age, gender, and disease duration) were taken into account. However, plasma α-synuclein levels were significantly higher in PD patients with dementia (PDD) than in PD patients with mild cognitive impairment (PD-MCI) or normal cognition (0.42 pg/mL, (95% CI 0.25 to 0.93) for PD with normal cognition; 1.29 pg/mL (95% CI 0.76 to 1.93) for PD-MCI and 4.09 pg/mL (95% CI 1.99 to 6.19) for PDD, p<0.01) and were negatively correlated with Mini-Mental State Examination scores (R2-adjusted=0.3004, p<0.001), even after confounder adjustment. CONCLUSIONS: Our data suggest that plasma α-synuclein level correlates with cognitive decline but not motor severity in patients with PD. Plasma α-synuclein could serve as a surrogate biomarker for patients at risk of cognitive decline.


Assuntos
Disfunção Cognitiva/sangue , Doença de Parkinson/complicações , alfa-Sinucleína/sangue , Biomarcadores/sangue , Disfunção Cognitiva/etiologia , Demência/sangue , Demência/etiologia , Humanos
7.
Sensors (Basel) ; 17(9)2017 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-28869515

RESUMO

In this work, we report characterizations of biofunctionalized magnetic nanoparticles (BMNPs) associated with alpha-fetoprotein (AFP) for biomedical applications. The example BMNP in this study is anti-alpha-fetoprotein (anti-AFP) conjugated onto dextran-coated Fe3O4 labeled as Fe3O4-anti-AFP, and the target is AFP. We characterize magnetic properties, such as increments of magnetization ΔMH and effective relaxation time Δτeff in the reaction process. It is found that both ΔMH and Δτeff are enhanced when the concentration of AFP, ФAFP, increases. The enhancements are due to magnetic interactions among BMNPs in magnetic clusters, which contribute extra MH after the association with MH and in turn enhance τeff. The screening of patients carrying hepatocellular carcinoma (HCC) is verified via ΔMH/MH. The proposed method can be applied to detect a wide variety of analytes. The scaling characteristics of ΔMH/MH show the potential to develop a vibrating sample magnetometer system with low field strength for clinic applications.


Assuntos
Nanopartículas de Magnetita , Carcinoma Hepatocelular , Humanos , Neoplasias Hepáticas , Magnetismo , alfa-Fetoproteínas
8.
Nanotechnology ; 27(23): 235101, 2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27138705

RESUMO

After a needle biopsy, immunohistochemistry is generally used to stain tissue slices for clinically confirming tumours. Currently, tissue slices are immersed in a bioprobe-linked fluorescent reagent for several minutes, washed to remove the unbound reagent, and then observed using a fluorescence microscope. However, the observation must be performed by experienced pathologists, and producing a qualitative analysis is time consuming. Therefore, this study proposes a novel scanning superconducting quantum interference device biosusceptometry (SSB) method for avoiding these drawbacks. First, stain reagents were synthesised for the dual modalities of fluorescent and magnetic imaging by combining iron-oxide magnetic nanoparticles and the currently used fluorescent reagent. The reagent for the proposed approach was stained using the same procedure as that for the current fluorescent reagent, and tissue slices were rapidly imaged using the developed SSB for obtaining coregistered optical and magnetic images. Analysing the total intensity of magnetic spots in SSB images enables quantitatively determining the tumour cells of tissue slices. To confirm the magnetic imaging results, a traditional observation methodology entailing the use of a fluorescence microscope was also performed as the gold standard. This study determined high consistency between the fluorescent and magnetic spots in different regions of the tissue slices, demonstrating the feasibility of the proposed approach, which will benefit future clinical pathology.


Assuntos
Neoplasias , Humanos , Magnetismo , Microscopia de Fluorescência , Nanopartículas
9.
J Nanobiotechnology ; 14(1): 41, 2016 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-27278241

RESUMO

BACKGROUND: It is difficult to discriminate healthy subjects and patients with Parkinson disease (PD) or Parkinson disease dementia (PDD) by assaying plasma α-synuclein because the concentrations of circulating α-synuclein in the blood are almost the same as the low-detection limit using current immunoassays, such as enzyme-linked immunosorbent assay. In this work, an ultra-sensitive immunoassay utilizing immunomagnetic reduction (IMR) is developed. The reagent for IMR consists of magnetic nanoparticles functionalized with antibodies against α-synuclein and dispersed in pH-7.2 phosphate-buffered saline. A high-Tc superconducting-quantum-interference-device (SQUID) alternative-current magnetosusceptometer is used to measure the IMR signal of the reagent due to the association between magnetic nanoparticles and α-synuclein molecules. RESULTS: According to the experimental α-synuclein concentration dependent IMR signal, the low-detection limit is 0.3 fg/ml and the dynamic range is 310 pg/ml. The preliminary results show the plasma α-synuclein for PD patients distributes from 6 to 30 fg/ml. For PDD patients, the concentration of plasma α-synuclein varies from 0.1 to 100 pg/ml. Whereas the concentration of plasma α-synuclein for healthy subjects is significantly lower than that of PD patients. CONCLUSIONS: The ultra-sensitive IMR by utilizing antibody-functionalized magnetic nanoparticles and high-Tc SQUID magnetometer is promising as a method to assay plasma α-synuclein, which is a potential biomarker for discriminating patients with PD or PDD.


Assuntos
Anticorpos Imobilizados/química , Demência/sangue , Nanopartículas de Magnetita/química , Doença de Parkinson/sangue , alfa-Sinucleína/sangue , Adulto , Idoso , Biomarcadores/sangue , Demência/diagnóstico , Feminino , Humanos , Imunoensaio/métodos , Limite de Detecção , Magnetismo/métodos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico
10.
J Nanobiotechnology ; 13: 11, 2015 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-25889863

RESUMO

BACKGROUND: For intraoperative imaging in operating theaters or preoperative imaging in clinics, compact and economic integration rather than large and expensive equipment is required to coregister structural and functional imaging. However, current technologies, such as those integrating optical and gamma cameras or infrared and fluorescence imaging, involve certain drawbacks, including the radioactive biorisks of nuclear medicine indicators and the inconvenience of conducting measurements in dark environments. METHODS: To specifically and magnetically label liver tumors, an anti-alpha-fetoprotein (AFP) reagent was synthesized from biosafe iron oxide magnetic nanoparticles (MNPs) coated with anti-AFP antibody and solved in a phosphate buffered saline solution. In addition, a novel dual-imaging model system integrating an optical camera and magnetic scanning superconducting-quantum-interference device (SQUID) biosusceptometry (SSB) was proposed. The simultaneous coregistration of low-field magnetic images of MNP distributions and optical images of anatomical regions enabled the tumor distribution to be determined easily and in real time. To simulate targeted MNPs within animals, fewer reagents than the injected dose were contained in a microtube as a sample for the phantom test. The phantom test was conducted to examine the system characteristics and the analysis method of dual images. Furthermore, the animal tests were classified into two types, with liver tumors implanted either on the backs or livers of rats. The tumors on the backs were to visually confirm the imaging results of the phantom test, and the tumors on the livers were to simulate real cases in hepatocellular carcinoma people. RESULTS: A phantom test was conducted using the proposed analysis method; favorable contour agreement was shown between the MNP distribution in optical and magnetic images. Consequently, the positioning and discrimination of liver tumors implanted on the backs and livers of rats were verified by conducting in vivo and ex vivo tests. The results of tissue staining verified the feasibility of using this method to determine the distribution of liver tumors. CONCLUSION: The results of this study indicate the clinical potential of using anti-AFP-mediated MNPs and the dual-imaging model SSB for discriminating and locating tumors.


Assuntos
Neoplasias Hepáticas Experimentais/diagnóstico , Nanopartículas de Magnetita , Magnetometria/métodos , Animais , Desenho de Equipamento , Processamento de Imagem Assistida por Computador/métodos , Cuidados Intraoperatórios , Neoplasias Hepáticas Experimentais/patologia , Magnetometria/instrumentação , Masculino , Imagens de Fantasmas , Cuidados Pré-Operatórios , Ratos , Ratos Endogâmicos F344 , Gravação em Vídeo/instrumentação , alfa-Fetoproteínas/química
11.
Hum Brain Mapp ; 35(7): 3132-42, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24129926

RESUMO

Neurofibrillary tangles are associated with cognitive dysfunction, and hippocampal atrophy with increased CSF tau markers. However, the plasma tau levels of Alzheimer's disease (AD) have not been well studied. We investigated plasma tau by using an immunomagnetic reduction assay in 20 patients with mild cognitive impairment (MCI) due to AD, 10 early AD dementia, and 30 healthy elders (HE). All received a 3D-brain MRI scan and a set of cognitive function test. We explored their relationships with both brain structure and cognitive functions. Images were analyzed to determine the brain volumes and gray matter densities. Patients with MCI or early AD had significantly increased plasma tau levels compared with HE. Plasma tau levels were negatively associated with the performance of logical memory, visual reproduction, and verbal fluency; also negatively associated with volume of total gray matter, hippocampus, amygdala; and gray matter densities of various regions. Regression analyses indicated that logical memory explained 0.394 and hippocampus volume predicted .608 of the variance of plasma tau levels, both P < 0.001. Education years were negatively associated with the gray matter densities of the supramarginal (r = -0.407), middle temporal gyrus (r = -0.40) and precuneus (r = -0.377; all P < 0.05) in HE; and negatively associated with plasma tau levels in patients (r = -0.626). We propose that plasma tau may serve as a window to both structure and function of the brain. Higher education is a protective factor against AD and is associated with lower plasma tau levels in patients.


Assuntos
Doença de Alzheimer , Encéfalo/patologia , Disfunção Cognitiva , Transtornos da Memória/etiologia , Proteínas tau/sangue , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/sangue , Doença de Alzheimer/complicações , Doença de Alzheimer/patologia , Apolipoproteínas E/genética , Disfunção Cognitiva/sangue , Disfunção Cognitiva/complicações , Disfunção Cognitiva/patologia , Feminino , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Nanopartículas , Testes Neuropsicológicos , Análise de Regressão
12.
Sensors (Basel) ; 14(11): 21409-17, 2014 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-25397920

RESUMO

In this work, we report the use of bio-functionalized magnetic nanoparticles (BMNs) and dynamic magnetic resonance (DMR) to characterize the time-dependent spin-spin relaxation time for sensitive bio-detection. The biomarkers are the human C-reactive protein (CRP) while the BMNs are the anti-CRP bound onto dextran-coated Fe3O4 particles labeled as Fe3O4-antiCRP. It was found the time-dependent spin-spin relaxation time, T2, of protons decreases as time evolves. Additionally, the ΔT2 of of protons in BMNs increases as the concentration of CRP increases. We attribute these to the formation of the magnetic clusters that deteriorate the field homogeneity of nearby protons. A sensitivity better than 0.1 µg/mL for assaying CRP is achieved, which is much higher than that required by the clinical criteria (0.5 mg/dL). The present MR-detection platform shows promise for further use in detecting tumors, viruses, and proteins.


Assuntos
Técnicas Biossensoriais/instrumentação , Proteína C-Reativa/análise , Dextranos/química , Separação Imunomagnética/instrumentação , Espectroscopia de Ressonância Magnética/instrumentação , Nanopartículas de Magnetita/química , Proteína C-Reativa/imunologia , Materiais Revestidos Biocompatíveis/síntese química , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Nanopartículas de Magnetita/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Marcadores de Spin
13.
Micromachines (Basel) ; 13(10)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36295958

RESUMO

Ablation is a clinical cancer treatment, but some demands are still unsatisfied, such as electromagnetic interferences amongst multiple ablation needles during large tumour treatments. This work proposes a physical synthesis for composite particles of biocompatible iron oxide particles and liquid metal gallium (Ga) with different alternative-current (AC)-magnetic-field-induced heat mechanisms of magnetic particle hyperthermia and superior resistance heat. By some imaging, X-ray diffraction, and vibrating sample magnetometer, utilised composite particles were clearly identified as the cluster of few iron oxides using the small weight ratio of high-viscosity liquid metal Ga as conjugation materials without surfactants for physical targeting of limited fluidity. Hence, well penetration inside the tissue and the promotion rate of heat generation to fit the ablation requirement of at least 60 °C in a few seconds are achieved. For the injection and the post-injection magnetic ablations, the volume variation ratios of mice dorsal tumours on Day 12 were expressed at around one without tumour growth. Its future powerful potentiality is expected through a percutaneous injection.

14.
Biosensors (Basel) ; 11(10)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34677319

RESUMO

Infections of orchids by the Odontoglossum ringspot virus or Cymbidium mosaic virus cause orchid disfiguration and are a substantial source of economic loss for orchid farms. Although immunoassays can identify these infections, immunoassays are expensive, time consuming, and labor consuming and limited to sampling-based testing methods. This study proposes a noncontact inspection platform that uses a spectrometer and Android smartphone. When orchid leaves are illuminated with a handheld optical probe, the Android app based on the Internet of Things and artificial intelligence can display the measured florescence spectrum and determine the infection status within 3 s by using an algorithm hosted on a remote server. The algorithm was trained on optical data and the results of polymerase chain reaction assays. The testing accuracy of the algorithm was 89%. The area under the receiver operating characteristic curve was 91%; thus, the platform with the algorithm was accurate and convenient for infection screening in orchids.


Assuntos
Orchidaceae , Smartphone , Inteligência Artificial , Doenças das Plantas/virologia , Reação em Cadeia da Polimerase , Potexvirus , Tobamovirus
15.
ACS Chem Neurosci ; 11(2): 191-196, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31799825

RESUMO

Dementia frequently occurs in Down syndrome (DS) patients, and early intervention is important in its management. We have previously demonstrated a positive correlation of plasma ß-amyloid Aß42 levels and negative correlations of Aß40 and tau levels with dementia in DS. In this study, we examined more cases and constructed composite scores with both tau and amyloids to correlate with dementia in DS. Plasma Aß42, Aß40, and tau proteins were measured by an immunomagnetic reduction assay in DS patients. Data were randomly and repeatedly split into training and validating sets, and logistic regression was applied to calculate the area under the curve (AUC) for each biomarker. A total of 73 DS patients (among them, 23 had neurodegeneration) and 77 controls were recruited. In DS patients without dementia, plasma Aß40 and tau levels were highly elevated, but Aß42 levels were lower than those of the healthy controls. DS patients with dementia, compared with DS patients with no dementia, had a large decline in Aß40 and tau but a rise in Aß42. For biomarker scores correlating with dementia, Aß40 revealed an AUC of 0.912; the composite score of Aß40 × tau revealed an AUC of 0.953; and a combined composite score of 0.1 for Aß40 × Tau +0.9 Tau × Aß40/Aß42 achieved the highest AUC of 0.965. Therefore, composite biomarker scores including both plasma tau and ß-amyloid levels correlate with dementia in DS better than using individual biomarker scores. The pattern of tau decline and Aß42 rise in DS patients with dementia are also different from previous findings in Alzheimer's disease.


Assuntos
Peptídeos beta-Amiloides/sangue , Biomarcadores/sangue , Demência/etiologia , Síndrome de Down/sangue , Síndrome de Down/complicações , Proteínas tau/sangue , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Appl Opt ; 48(29): 5604-11, 2009 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-19823245

RESUMO

We use a heterodyne Mach-Zehnder interferometer to simultaneously and simply measure the complex refractive index by only normal incidence on the specimen, instead of using a complicated measurement procedure or instrument that only measures the real or imaginary part of the complex refractive index. To study the tiny variation of the complex refractive index, the small complex refractive-index variation of a rare-concentration magnetic-fluid thin film, due to a weak field of less than 200 Oe, was processed by this interferometer. We also present the wavelength trend of the complex refractive index of magnetic fluids to verify the appearance of the slight change in a small wavelength range.


Assuntos
Interferometria/instrumentação , Membranas Artificiais , Refratometria/instrumentação , Reologia/instrumentação , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Magnetismo , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Neurology ; 93(11): e1104-e1111, 2019 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-31420461

RESUMO

OBJECTIVE: To examine whether plasma neurofilament light chain (NfL) levels were associated with motor and cognitive progression in Parkinson disease (PD). METHODS: This prospective follow-up study enrolled 178 participants, including 116 with PD, 22 with multiple system atrophy (MSA), and 40 healthy controls. We measured plasma NfL levels with electrochemiluminescence immunoassay. Patients with PD received evaluations of motor and cognition at baseline and at a mean follow-up interval of 3 years. Changes in the Unified Parkinson's Disease Rating Scale (UPDRS) part III motor score and Mini-Mental State Examination score were used to assess motor and cognition progression. RESULTS: Plasma NfL levels were significantly higher in the MSA group than in the PD and healthy groups (35.8 ± 6.2, 17.6 ± 2.8, and 10.6 ± 2.3 pg/mL, respectively, p < 0.001). In the PD group, NfL levels were significantly elevated in patients with advanced Hoehn-Yahr stage and patients with dementia (p < 0.001). NfL levels were modestly correlated with UPDRS part III scores (r = 0.42, 95% confidence interval 0.46-0.56, p < 0.001). After a mean follow-up of 3.4 ± 1.2 years, a Cox regression analysis adjusted for age, sex, disease duration, and baseline motor or cognitive status showed that higher baseline NfL levels were associated with higher risks for either motor or cognition progression (p = 0.029 and p = 0.015, respectively). CONCLUSIONS: Plasma NfL levels correlated with disease severity and progression in terms of both motor and cognitive functions in PD. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that plasma NfL level distinguishes PD from MSA and is a surrogate biomarker for PD progression.


Assuntos
Progressão da Doença , Proteínas de Neurofilamentos/sangue , Doença de Parkinson/sangue , Doença de Parkinson/diagnóstico , Índice de Gravidade de Doença , Idoso , Biomarcadores/sangue , Feminino , Seguimentos , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/psicologia , Estudos Prospectivos
18.
Front Aging Neurosci ; 10: 123, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29755341

RESUMO

Objective: Parkinson's disease (PD) has significant clinical overlaps with atypical parkinsonism syndromes (APS), which have a poorer treatment response and a more aggressive course than PD. We aimed to identify plasma biomarkers to differentiate PD from APS. Methods: Plasma samples (n = 204) were obtained from healthy controls and from patients with PD, dementia with Lewy bodies (DLB), multiple system atrophy, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), or frontotemporal dementia (FTD) with parkinsonism (FTD-P) or without parkinsonism. We measured plasma levels of α-synuclein, total tau, p-Tau181, and amyloid beta 42 (Aß42) by immunomagnetic reduction-based immunoassay. Results: Plasma α-synuclein level was significantly increased in patients with PD and APS when compared with controls and FTD without parkinsonism (p < 0.01). Total tau and p-Tau181 were significantly increased in all disease groups compared to controls, especially in patients with FTD (p < 0.01). A multivariate and receiver operating characteristic curve analysis revealed that a cut-off value for Aß42 multiplied by p-Tau181 for discriminating patients with FTD from patients with PD and APS was 92.66 (pg/ml)2, with an area under the curve (AUC) of 0.932. An α-synuclein cut-off of 0.1977 pg/ml could separate FTD-P from FTD without parkinsonism (AUC 0.947). In patients with predominant parkinsonism, an α-synuclein cut-off of 1.388 pg/ml differentiated patients with PD from those with APS (AUC 0.87). Conclusion: Our results suggest that integrated plasma biomarkers improve the differential diagnosis of PD from APS (PSP, CBD, DLB, and FTD-P).

19.
ACS Nano ; 11(3): 3030-3037, 2017 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-28276684

RESUMO

Biofunctional magnetic nanoparticles (MNPs) have been widely applied in biomedical engineering. MNPs are used as a contrast medium in magnetic imaging. Current methods of magnetic imaging, such as magnetic particle imaging and magnetic relaxometry, use small amounts of MNPs at target points far from the surface of the patient's body; these methods always consume considerable power to produce magnetic fields of high uniformity or gradient excitations. Some drawbacks, such as a limited imaging region, imaging system shielding, and complex algorithms based on assumptions of MNP properties or environmental factors, also limit the application of MNP methods in clinics. Therefore, this work proposes an interdisciplinary methodology of ultrasound-induced magnetic imaging that lacks these drawbacks. In the proposed imaging method, magnet sets were designed with uniform magnetic fields to magnetize MNPs. Besides, magnetized MNPs are subjected to ultrasound vibrations; the motion of the MNPs induces weak induction voltages at the imaging pickup coils. The highly sensitive scanning superconducting quantum interference device biosusceptometry with three sets of ultrasound focus chips was developed to construct magnetic tomography at three depths. A phantom test showed favorable consistency between the visual photos and the magnetic images of alpha-fetoprotein antibody (anti-AFP) MNP distribution on gauzes. In animal tests, rats with liver tumors were imaged at the pre-injection and post-injection of anti-AFP MNPs. The consistent results of magnetic images and ultrasound images implied that the proposed method has high clinical potential.


Assuntos
Neoplasias Hepáticas/diagnóstico , Campos Magnéticos , Nanopartículas de Magnetita/química , Ultrassonografia , alfa-Fetoproteínas/química , Animais , Magnetismo , Ratos
20.
IEEE Trans Biomed Eng ; 63(8): 1681-6, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26415145

RESUMO

The accredited biomarker alpha-fetoprotein (AFP) offers limited sensitivity and specificity in the early detection of hepatocellular carcinoma (HCC). To improve the screening performance, des-gamma-carboxy prothrombin (DCP) has been identified as another promising biomarker of HCC, combined with AFP biomarkers. The results of the commercial optical enzyme-linked immunosorbent assay (ELISA) kit easily have the interference problem due to the optical methodology. The immunomagnetic reduction (IMR) assay based on the magnetic measurement was utilized to assay DCP biomarkers without the excellent antiinterference performances. A DCP magnetic reagent, composed of iron-oxide (Fe3O4 ) magnetic nanoparticles coated with anti-DCP antibodies solved in phosphoryl-buffer solution, was synthesized and characterized. In the test of standard DCP antigens, superior antiinterference and sensitivity than optical ELISA were proved. In the animal test, the results indicate good agreement between the IMR assay findings and the tumor sizes of HCC rats at all time points after the HCC implantation. The feasibility of the developed DCP magnetic reagent with the IMR for the detection of DCP is verified, and demonstrates the high potential for future clinical applications.


Assuntos
Biomarcadores Tumorais/análise , Biomarcadores/análise , Carcinoma Hepatocelular/química , Ensaio de Imunoadsorção Enzimática/métodos , Separação Imunomagnética/métodos , Neoplasias Hepáticas/química , Precursores de Proteínas/análise , Protrombina/análise , Animais , Biomarcadores/sangue , Biomarcadores/química , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/química , Estudos de Viabilidade , Nanopartículas de Magnetita/química , Masculino , Precursores de Proteínas/sangue , Precursores de Proteínas/química , Protrombina/química , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA