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1.
Cureus ; 16(4): e57993, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38738130

RESUMO

Bickerstaff brainstem encephalitis (BBE) is a rare disorder that is characterized by ophthalmoplegia, ataxia, and disturbance in consciousness. Definite diagnosis is made primarily through clinical presentation and serology testing with anti-GQ1b antibody. However, in a country where access to serologic testing is scarce, electrophysiologic tests such as brainstem auditory evoked response (BAER) may contribute to the diagnosis. Due to its rarity and generally good prognosis, there is no established consensus for the treatment of BBE. Immunomodulatory treatments such as intravenous immunoglobulin (IVIG), plasma exchange, steroids, or a combination of these therapies are often used with good response. However, there are severe cases that respond poorly to these conventional treatments. We report the case of a 26-year-old Filipino man who came in for sudden onset of diplopia, with a one-week history of upper respiratory tract infection. Subsequently, he developed paresthesias, quadriparesis, and an altered level of consciousness. On initial examination, he only had partial third nerve palsy, but eventually became quadriparetic and obtunded during admission. Initial electromyography and nerve conduction velocity (EMG-NCV) study showed a reduced recruitment pattern of the right rectus femoris, absent H reflexes of bilateral posterior tibial nerves, and no abnormal increase in temporal dispersion. Cranial MRI with contrast was unremarkable. Video electroencephalogram (video-EEG) showed intermittent generalized 5-6 Hz and 6-7 Hz theta slowing of the background activity in the stimulated state. BAER was done revealing bilateral partial dysfunction of the auditory pathways to support brainstem involvement of the disease. He received IVIG and methylprednisolone pulse therapy with no significant clinical improvement. Hence, he was given a rituximab infusion. One week post-rituximab, he had sustained wakefulness and was able to move his extremities.

2.
Eur J Cancer ; 178: 37-48, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36399909

RESUMO

BACKGROUND: In patients with RAS wild-type metastatic colorectal cancer, depth of response (DpR) has gained importance as a novel end-point in clinical trials. We investigated the overall DpR, as well as the prognostic and predictive impact of DpR to induction therapy (six cycles of 5-fluorouracil, leucovorin [FU/FA], oxaliplatin [FOLFOX] and panitumumab [Pmab]) on consecutive maintenance therapy (FU/FA plus Pmab or FU/FA alone) in patients treated within the PanaMa trial. METHODS: Central radiological assessment was performed according to RECIST 1.1. DpR was defined as percentage change in tumour diameter within defined time intervals (induction therapy, maintenance therapy, total course of therapy). For prognostic and predictive analyses, median DpR (

Assuntos
Neoplasias do Colo , Neoplasias Colorretais , Neoplasias Retais , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Fluoruracila/uso terapêutico , Quimioterapia de Indução , Leucovorina/uso terapêutico , Panitumumabe , Neoplasias Retais/tratamento farmacológico
3.
Asian J Psychiatr ; 67: 102946, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34871966

RESUMO

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive treatment option for psychiatric conditions, including catatonia. Our patient is a 30-year-old Filipino female admitted due to mutism, motor, and behavioral changes. Laboratory tests, cranial magnetic resonance imaging, electroencephalogram and cerebrospinal fluid analysis were unremarkable. The patient was diagnosed with stuporous catatonia and was given psychiatric medications, without significant improvement. The patient underwent 10 sessions of rTMS and showed marked improvement of symptoms. This highlights rTMS as a treatment option for catatonic patients that do not respond to pharmacotherapy or in situations where ECT is contraindicated or not available.


Assuntos
Catatonia , Transtornos Mentais , Adulto , Povo Asiático , Catatonia/terapia , Hospitalização , Humanos , Estimulação Magnética Transcraniana , Resultado do Tratamento
4.
Case Rep Oncol ; 14(3): 1516-1521, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34899245

RESUMO

Renal cell carcinoma is one of the leading causes of cancer worldwide. Brain metastasis is a poor prognostic factor among patients with this disease. The advancements in understanding of the molecular framework behind malignancy and brain metastasis led to more sophisticated treatment regimens which include targeted drugs and immunotherapy. While the role of tyrosine kinase inhibitors in metastatic renal cell carcinoma has been proven in the literature, its specific role among patients with brain metastasis has not yet been fully elucidated. We report a case of a Filipino male with renal cell carcinoma and brain metastasis who underwent stereotactic radiosurgery of his right frontal lesion followed by pazopanib taken initially at 800 mg/day and then decreased to 600 mg/day. A significant increase in creatinine level led to the discontinuation of the medication after >3 years. He had a remarkable progression-free survival of 38 months. This is the first documented case of such significant response to pazopanib in a patient with renal cell carcinoma and brain metastasis. In the Philippine setting where options for cancer treatment are limited by the prohibitive cost of medications, this case can support the use of pazopanib as a potent agent for treating patients with this condition.

5.
Sci Rep ; 10(1): 7480, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366912

RESUMO

Temperature-resolved magnetic particle imaging (MPI) represents a promising tool for medical imaging applications. In this study an approach based on a single calibration measurement was applied for highlighting the potential of MPI for monitoring of temperatures during thermal ablation of liver tumors. For this purpose, liver tissue and liver tumor phantoms embedding different superparamagnetic iron oxide nanoparticles (SPION) were prepared, locally heated up to 70 °C and recorded with MPI. Optimal temperature MPI SPIONs and a corresponding linear model for temperature calculation were determined. The temporal and spatial temperature distributions were compared with infrared (IR) camera results yielding quantitative agreements with a mean absolute deviation of 1 °C despite mismatches in boundary areas.


Assuntos
Hipertermia Induzida , Raios Infravermelhos , Neoplasias Hepáticas , Nanopartículas de Magnetita , Tomografia Óptica , Animais , Galinhas , Fígado , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/terapia
6.
J Clin Neurosci ; 71: 297-299, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31477466

RESUMO

Chronic inflammatory demyelinating polyneuropathy is one of the immune-mediated polyneuropathies responsive to immunotherapy. Its usual clinical presentation is a chronic course of symmetric sensorimotor affectation of both proximal and distal extremities with signs of demyelination on electrophysiologic studies. Cranial nerve signs in this condition is not commonly encountered, particularly involvement of the hypoglossal nerve. To date, there are only three published cases of hypoglossal involvement in this condition. This case report presents a patient with tongue fasciculation, which is an uncommon finding in chronic inflammatory demyelinating polyneuropathy. This paper highlights the importance of considering chronic inflammatory demyelinating polyneuropathy in the differential diagnoses of a patient with tongue fasciculation as it has been found to be responsive to immunotherapy in comparison to other lower motor neuron syndromes.


Assuntos
Fasciculação/etiologia , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/complicações , Língua , Adulto , Diagnóstico Diferencial , Humanos , Masculino , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/diagnóstico
7.
Mult Scler Relat Disord ; 31: 124-130, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30981191

RESUMO

Neuromyelitis optica spectrum disorder (NMOSD) is a rare disease that commonly presents with optic nerve and spinal cord inflammation, and it is associated with the presence of aquaporin-4 immunoglobulin G antibody (AQP4-IgG). Information on the clinical profile and occurrence of NMOSD among Filipino patients, however, is not sufficiently documented. In this series, we presented eighteen (18) patients with NMOSD consecutively seen in the Philippine General Hospital, a major tertiary referral center. Demographic data showed a female-to-male ratio of 2.6:1. Median age of onset of symptoms was 26 years. Eight patients (53.3%) were positive for AQP4-IgG. Most patients initially presented with myelitis (56.6%) and followed by optic neuritis (16.7%) and area postrema syndrome (16.7%). All patients had longitudinally extensive transverse myelitis on magnetic resonance imaging (MRI). Cranial MRI rarely demonstrated lesions in the optic nerves (18.2%). CSF pleocytosis (33%) and increased protein (8.3%) were infrequent. These results demonstrated that the profile of Filipino patients with NMOSD seen in our institution strengthens those described in other populations with this disorder. Large scale cross-sectional studies are necessary to fully define the profile of these patients and to determine with accuracy the prevalence and incidence of this disorder in the Philippines. Further investigation regarding the utility of ancillary tests as diagnostic and prognostic indicators in patients with NMOSD are also suggested by the authors.


Assuntos
Neuromielite Óptica/epidemiologia , Adulto , Idade de Início , Aquaporina 4/imunologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Feminino , Humanos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Neuromielite Óptica/diagnóstico por imagem , Neuromielite Óptica/imunologia , Neuromielite Óptica/patologia , Filipinas , Medula Espinal/diagnóstico por imagem , Medula Espinal/patologia , Centros de Atenção Terciária , Adulto Jovem
8.
Rev Sci Instrum ; 90(2): 024101, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30831678

RESUMO

Superparamagnetic iron oxide nanoparticles (SPIONs) are used as a tracer material in sentinel node biopsies. The latter is a procedure to analyze if cancer cells have spread to lymph nodes, helping to personalize patient care. To predict SPION behavior in vivo, it is important to analyze their magnetic properties in biological environments. The superparamagnetic quantifier (SPaQ) is a new device to measure the dynamic magnetization curve of SPIONs. The magnetization curve was measured for two types of SPIONs: Resovist and SHP-25. We used three techniques: Vibrating Sample Magnetometry (VSM), Magnetic Particle Spectroscopy (MPS), and our new SPaQ. Furthermore, AC susceptibility (ACS) measurements were performed as part of the evaluation of the three techniques. SPaQ and VSM results were found to be similar. Measurement results were nearly identical in both directions, indicating minor hysteresis. However, in MPS measurements, a clear hysteresis loop was observed. Furthermore, the ACS measurements showed a pronounced Brownian maximum, indicating an optimal response for an AC frequency below 10 kHz for both particle systems. Both the SPaQ and MPS were found to be superior to VSM since measurements are faster, can be performed at room temperature, and are particularly sensitive to particle dynamics. The main difference between the SPaQ and MPS lies in the excitation sequence. The SPaQ combines an alternating magnetic field that has a low amplitude with a gradual DC offset, whereas MPS uses only an alternating field that has a large amplitude. In conclusion, both the SPaQ and MPS are highly suited to improve understanding SPION behavior, which will lead to the radical improvement of sentinel node biopsy accuracy.

9.
Nanotechnology ; 29(42): 425705, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30052525

RESUMO

Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinTMR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinTMXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 105 rad s-1, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.

10.
Acute Med ; 17(4): 178-181, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30882100

RESUMO

The aim was to classify patients who returned unscheduled to an emergency department within 7 days. We categorized the patients' cases arbitrarily according to the underlying cause of the return. The main causes for returning unscheduled were: "patient related" (24,2%), "illness related" (35,4%), "physician related" (18,3%), "system related" (3,8%) and "other" (21,7%). We also analyzed missed diagnoses, as the literature describes this special patient population as a high risk group. 15,4% of all return cases had a wrong diagnosis. No typical risk constellation/symptom could be found. Vital signs or blood values were within normal limits as well.


Assuntos
Serviço Hospitalar de Emergência , Readmissão do Paciente , Alemanha , Humanos , Médicos , Sinais Vitais
11.
Sci Rep ; 7(1): 14274, 2017 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-29079753

RESUMO

Norrin is a secreted signaling molecule activating the Wnt/ß-catenin pathway. Since Norrin protects retinal neurons from experimental acute injury, we were interested to learn if Norrin attenuates chronic damage of retinal ganglion cells (RGC) and their axons in a mouse model of glaucoma. Transgenic mice overexpressing Norrin in the retina (Pax6-Norrin) were generated and crossed with DBA/2J mice with hereditary glaucoma and optic nerve axonal degeneration. One-year old DBA/2J/Pax6-Norrin animals had significantly more surviving optic nerve axons than their DBA/2J littermates. The protective effect correlated with an increase in insulin-like growth factor (IGF)-1 mRNA and an enhanced Akt phosphorylation in DBA/2J/Pax6-Norrin mice. Both mouse strains developed an increase in intraocular pressure during the second half of the first year and marked degenerative changes in chamber angle, ciliary body and iris structure. The degenerations were slightly attenuated in the chamber angle of DBA/2J/Pax6-Norrin mice, which showed a ß-catenin increase in the trabecular meshwork. We conclude that high levels of Norrin and the subsequent constitutive activation of Wnt/ß-catenin signaling in RGC protect from glaucomatous axonal damage via IGF-1 causing increased activity of PI3K-Akt signaling. Our results identify components of a protective signaling network preventing degeneration of optic nerve axons in glaucoma.


Assuntos
Axônios/patologia , Proteínas do Olho/metabolismo , Glaucoma/metabolismo , Glaucoma/patologia , Proteínas do Tecido Nervoso/metabolismo , Nervo Óptico/patologia , Animais , Modelos Animais de Doenças , Fator de Crescimento Insulin-Like I/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Ganglionares da Retina/metabolismo , Células Ganglionares da Retina/patologia , Transdução de Sinais
12.
Nanoscale ; 9(16): 5094-5101, 2017 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-28397910

RESUMO

Hysteresis losses in magnetic nanoparticles constitute the basis of magnetic hyperthermia for delivering a local thermal stress. Nevertheless, this therapeutic modality is only to be realised through a careful appraisal of the best possible intrinsic and extrinsic conditions to the nanoparticles for which they maximise and preserve their heating capabilities. Low frequency (100 kHz) hysteresis loops accurately probe the dynamical magnetic response of magnetic nanoparticles in a more reliable manner than calorimetry measurements, providing conclusive quantitative data under different experimental conditions. We consider here a set of iron oxide or cobalt ferrite nanocubes of different sizes, through which we experimentally and theoretically study the influence of the viscosity of the medium on the low frequency hysteresis loops of magnetic colloids, and hence their ability to produce and dissipate heat to the surroundings. We analyse the role of nanoparticle size, size distribution, chemical composition, and field intensity in making the magnetisation dynamics sensitive to viscosity. Numerical simulations using the stochastic Landau-Lifshitz-Gilbert equation model the experimental observations in excellent agreement. These results represent an important contribution towards predicting viscosity effects and hence to maximise heat dissipation from magnetic nanoparticles regardless of the environment.

13.
Rev Sci Instrum ; 88(3): 035006, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28372431

RESUMO

Magnetoresistive (MR) sensors and sensor systems are used in a large variety of applications in the field of industrial automation, automotive business, aeronautic industries, and instrumentation. Different MR sensor technologies like anisotropic magnetoresistive, giant magnetoresistive, and tunnel magnetoresistive sensors show strongly varying properties in terms of magnetoresistive effect, response to magnetic fields, achievable element miniaturization, manufacturing effort, and signal-to-noise ratio. Very few data have been reported so far on the comparison of noise performance for different sensor models and technologies, especially including the temperature dependence of their characteristics. In this paper, a stand-alone measurement setup is presented that allows a comprehensive characterization of MR sensors including sensitivity and noise over a wide range of temperatures.

14.
Klin Monbl Augenheilkd ; 234(9): 1146-1153, 2017 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-28380651

RESUMO

Background Optical coherence tomography angiography (OCTA) offers the possibility to visualize, non-invasively, blood vessels of the retina. In vascular tumors, especially hemangioblastomas in Hippel-Lindau disease, new information can be obtained with OCTA concerning structure of the tumor, tumor activity and treatment success. Patients Ten eyes of 10 patients with retinal hemangioblastoma in Hippel-Lindau disease were included. The age of the patients ranged from 19 years to 65 years (median 44 years). Results A total of 10 active and one inactive hemangioblastomas were examined with OCTA. In larger tumors, only the superficial blood flow could be visualized. Four hemangioblastomas were not treated due to their location near the optic nerve head. Six hemangioblastomas in the peripheral retina were treated with laser photocoagulation. In 4 eyes, a reduced blood flow could be shown directly after the treatment. The visualization of the perfusion was partially blocked after laser treatment. Conclusion OCTA enables innovative methods of pre- and postoperative assessment of retinal hemangioblastomas. It has the potential to give new information about the morphology, activity and effects of treatment. Prospective studies with longer follow-up are needed to evaluate the therapeutic relevance of this new imaging method.


Assuntos
Angiografia/métodos , Hemangioblastoma/diagnóstico por imagem , Hemangioblastoma/cirurgia , Neoplasias da Retina/diagnóstico por imagem , Neoplasias da Retina/cirurgia , Tomografia de Coerência Óptica/métodos , Doença de von Hippel-Lindau/diagnóstico por imagem , Doença de von Hippel-Lindau/cirurgia , Adulto , Feminino , Seguimentos , Humanos , Fotocoagulação a Laser , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/cirurgia , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/cirurgia , Reoperação , Adulto Jovem
15.
Phys Med Biol ; 62(9): 3470-3482, 2017 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-28035904

RESUMO

Magnetic particle imaging (MPI) facilitates the rapid determination of 3D in vivo magnetic nanoparticle distributions. In this work, liver MPI following intravenous injections of ferucarbotran (Resovist®) was studied. The image reconstruction was based on a calibration measurement, the so called system function. The application of an enhanced system function sample reflecting the particle mobility and aggregation status of ferucarbotran resulted in significantly improved image reconstructions. The finding was supported by characterizations of different ferucarbotran compositions with the magnetorelaxometry and magnetic particle spectroscopy technique. For instance, similar results were obtained between ferucarbotran embedded in freeze-dried mannitol sugar and liver tissue harvested after a ferucarbotran injection. In addition, the combination of multiple shifted measurement patches for a joint reconstruction of the MPI data enlarged the field of view and increased the covering of liver MPI on magnetic resonance images noticeably.


Assuntos
Meios de Contraste/química , Dextranos/química , Processamento de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Nanopartículas de Magnetita/química , Imagem Molecular/métodos , Animais , Calibragem , Meios de Contraste/administração & dosagem , Meios de Contraste/farmacocinética , Dextranos/administração & dosagem , Dextranos/farmacocinética , Fígado/metabolismo , Nanopartículas de Magnetita/administração & dosagem , Camundongos , Distribuição Tecidual
16.
Nano Lett ; 16(2): 1150-5, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26788750

RESUMO

We demonstrate the ability of Mössbauer spectroscopy to simultaneously investigate Brownian motion and Néel relaxation in ferrofluidic samples. For this purpose, Mössbauer spectra of coated iron oxide nanoparticles with core diameters of 6.0-26.4 nm dissolved in 70 vol % glycerol solution were recorded in the temperature range of 234-287 K and compared to low-temperature spectra without Brownian motion. By comparison to theory, we were able to determine the particle coating thickness and the dynamic viscosity of the fluid from the broadening of the absorption lines (Brownian motion), as well as the state of Néel relaxation. Results from Mössbauer spectroscopy were crosschecked by AC-susceptometry at several temperatures for Brownian motion and in the high-frequency regime (100 Hz-1 MHz) for Néel relaxation.

17.
Exp Eye Res ; 145: 317-326, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-26706283

RESUMO

Norrin is an angiogenic signaling molecule that activates canonical Wnt/ß-catenin signaling, and is involved in capillary formation in retina and brain. Moreover, Norrin induces vascular repair following an oxygen-induced retinopathy (OIR), the model of retinopathy of prematurity in mice. Since insulin-like growth factor (IGF)-1 is a very potent angiogenic molecule, we investigated if IGF-1 is a downstream mediator of Norrin's angiogenic properties. In retinae of transgenic mice with an ocular overexpression of Norrin (ßB1-Norrin), we found at postnatal day (P)11 a significant increase of IGF-1 mRNA compared to wild-type littermates. In addition, after treatment of cultured Müller cells or dermal microvascular endothelial cells with Norrin we observed an increase of IGF-1 and its mRNA, an effect that could be blocked with DKK-1, an inhibitor of Wnt/ß-catenin signaling. When OIR was induced, the expression of IGF-1 was significantly suppressed in both transgenic ßB1-Norrin mice and wild-type littermates when compared to wild-type animals that were housed in room air. Furthermore, at P13, one day after the mice had returned to normoxic conditions, IGF-1 levels were significantly higher in transgenic mice compared to wild-type littermates. Finally, after intravitreal injections of inhibitory α-IGF-1 antibodies at P12 or at P12 and P14, the Norrin-mediated vascular repair was significantly attenuated. We conclude that Norrin induces the expression of IGF-1 via an activation of the Wnt/ß-catenin signaling pathway, an effect that significantly contributes to the protective effects of Norrin against an OIR.


Assuntos
Proteínas do Olho/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Proteínas do Tecido Nervoso/fisiologia , Neovascularização Retiniana/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Ependimogliais/efeitos dos fármacos , Células Ependimogliais/metabolismo , Proteínas do Olho/farmacologia , Humanos , Fator de Crescimento Insulin-Like I/antagonistas & inibidores , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/farmacologia , Oxigênio/efeitos adversos , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Neovascularização Retiniana/etiologia , Via de Sinalização Wnt/fisiologia
18.
Nanoscale Res Lett ; 10(1): 992, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26153125

RESUMO

Nanoparticles experience increasing interest for a variety of medical and pharmaceutical applications. When exposing nanomaterials, e.g., magnetic iron oxide nanoparticles (MNP), to human blood, a protein corona consisting of various components is formed immediately. The composition of the corona as well as its amount bound to the particle surface is dependent on different factors, e.g., particle size and surface charge. The actual composition of the formed protein corona might be of major importance for cellular uptake of magnetic nanoparticles. The aim of the present study was to analyze the formation of the protein corona during in vitro serum incubation in dependency of incubation time and temperature. For this, MNP with different shells were incubated in fetal calf serum (FCS, serving as protein source) within a water bath for a defined time and at a defined temperature. Before and after incubation the particles were characterized by a variety of methods. It was found that immediately (seconds) after contact of MNP and FCS, a protein corona is formed on the surface of MNP. This formation led to an increase of particle size and a slight agglomeration of the particles, which was relatively constant during the first minutes of incubation. A longer incubation (from hours to days) resulted in a stronger agglomeration of the FCS incubated MNP. Quantitative analysis (gel electrophoresis) of serum-incubated particles revealed a relatively constant amount of bound proteins during the first minutes of serum incubation. After a longer incubation (>20 min), a considerably higher amount of surface proteins was determined for incubation temperatures below 40 °C. For incubation temperatures above 50 °C, the influence of time was less significant which might be attributed to denaturation of proteins during incubation. Overall, analysis of the molecular weight distribution of proteins found in the corona revealed a clear influence of incubation time and temperature on corona composition.

19.
IEEE Trans Magn ; 51(2)2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26052157

RESUMO

The drive-field frequency of Magnetic Particle Imaging (MPI) systems plays an important role for system design, safety requirements and tracer selection. Because the commonly utilized MPI drive-field frequency of 25 kHz might be increased in future system generations to avoid peripheral nerve stimulation, a performance evaluation of tracers at higher frequencies is desirable. We have studied single-core magnetite nanoparticles that were optimized for MPI applications, utilizing Magnetic Particle Spectrometers (MPS) with drive-field frequencies in the range from 1 kHz up to 100 kHz. The particles have core diameters of 25 nm and a hydrodynamic size of 77 nm. Measurements in the frequency range above 5 kHz were carried out with a newly designed MPS system. In addition, to exclude possible particle interaction, samples of different concentrations were characterized and compared.

20.
Mol Genet Metab Rep ; 2: 34-37, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28649523

RESUMO

Mucolipidosis II and III alpha/beta (ML II/III alpha/beta) are rare autosomal recessive lysosomal storage diseases that are caused by a deficiency of UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase, the enzyme responsible for the synthesis of the mannose 6-phosphate targeting signal on lysosomal hydrolases. A Brazilian patient suspected of having a very mild ML III was investigated using whole next-generation sequencing (NGS). Two mutations in the GNPTAB gene were detected and confirmed to be in trans status by parental analysis: c.1208T>C (p.Ile403Thr), previously reported as being pathogenic, and the novel mutation c.1723G>A (p.Gly575Arg). This study demonstrates the effectiveness of using whole NGS for the molecular diagnosis of very mild ML III alpha/beta patients.

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