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Made available in DSpace on 2020-12-12T01:46:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Cerebral blood flow (CBF) assessment is mainly performed by scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI). New approaches to assess the CBF through the passage of magnetic nanoparticles (MNPs) to blood-brain barrier (BBB) are convenient to help decrease the use of ionizing radiation and unleash the required MRI schedule in clinics. The development of nanomedicine and new biomedical devices, such as the magnetic particle imaging (MPI), enabled new approaches to study dynamic brain blood flow. In this paper, we employed MNPs and the alternating current biosusceptometry (ACB) to study the brain perfusion. We utilized the mannitol, before the MNPs, injection to modulate the BBB permeability and study its effects on the circulation time of the MNPs in the brain of rats. Also, we characterized a new ACB sensor to increase the systems' applicability to study the MNPs' accumulation, especially in the animals' brain. Our data showed that the injection of mannitol increased the circulation time of MNPs in the brain. Also, the mannitol increased the accumulation of MNPs in the brain. This paper suggests the use of the ACB as a tool to study brain perfusion and accumulation of MNPs in studies of new nano agents focused on the brain diagnostics and treatment. Department of Physics and Biophysics UNESP São Paulo State University Biosciences Institute of Botucatu, Prof. Antonio Celso Wagner Zanin Street Institute of Physics Federal University of Goiás Department of Physics and Biophysics UNESP São Paulo State University Biosciences Institute of Botucatu, Prof. Antonio Celso Wagner Zanin Street

Made available in DSpace on 2018-11-26T15:43:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-21 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundacao de Amparo a Pesquisa do estado de Goias (FAPEG) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Background: We introduce and demonstrate that the AC biosusceptometry (ACB) technique enables real-time monitoring of magnetic nanoparticles (MNPs) in the bloodstream. We present an ACB system as a simple, portable, versatile, non-invasive, and accessible tool to study pharmacokinetic parameters of MNPs, such as circulation time, in real time. We synthesized and monitored manganese doped iron oxide nanoparticles in the bloodstream of Wistar rats using two different injection protocols. Aiming towards a translational approach, we also simultaneously evaluated cardiovascular parameters, including mean arterial pressure, heart rate, and episodes of arrhythmia in order to secure the well-being of all animals. Results: We found that serial injections increased the circulation time compared with single injections. Immediately after each injection, we observed a transitory drop in arterial pressure, a small drop in heart rate, and no episodes of arrhythmia. Although some cardiovascular effects were observed, they were transitory and easily recovered in both protocols. Conclusions: These results indicate that the ACB system may be a valuable tool for in vivo, real-time MNP monitoring that allows associations with other techniques, such as pulsatile arterial pressure and electrocardiogram recordings, helping ensuring the protocol safety, which is a fundamental step towards clinical applications. Sao Paulo State Univ, Biosci Inst Botucatu, Botucatu, SP, Brazil Univ Fed Goias, Inst Phys, Goiania, Go, Brazil Univ Sao Paulo, Ribeirao Preto Sch Med, Ribeirao Preto, SP, Brazil Univ Fed Goias, Inst Fis, BR-74690900 Goiania, Go, Brazil Sao Paulo State Univ, Biosci Inst Botucatu, Botucatu, SP, Brazil

Made available in DSpace on 2018-11-26T17:34:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We describe the development of a joint in vivo/ex vivo protocol to monitor magnetic nanoparticles in animal models. Alternating current biosusceptometry (ACB) enables the assessment of magnetic nanoparticle accumulation, followed by quantitative analysis of concentrations in organs of interest. We present a study of real-time liver accumulation, followed by the assessment of sequential biodistribution using the same technique. For quantification, we validated our results by comparing all of the data with electron spin resonance (ESR). The ACB had viable temporal resolution and accuracy to differentiate temporal parameters of liver accumulation, caused by vasculature extravasation and macrophages action. The biodistribution experiment showed different uptake profiles for different doses and injection protocols. Comparisons with the ESR system indicated a correlation index of 0.993. We present the ACB system as an accessible and versatile tool to monitor magnetic nanoparticles, allowing in vivo and real-time evaluations of distribution and quantitative assessments of particle concentrations. (C) 2017 Elsevier Inc. All rights reserved. Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Fed Goias, Inst Fis, Goiania, Go, Brazil Univ Texas MD Anderson Canc Ctr, Dept Expt Radiat Oncol, Houston, TX 77030 USA Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil Univ Sao Paulo, Fac Med Ribeirao Preto, Ribeirao Preto, SP, Brazil Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, Ribeirao Preto, SP, Brazil Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil FAPESP: 2010/07639-9 FAPESP: 2011/18696-6 FAPESP: 2013/20842-6 FAPESP: 2015/14914-0

Background This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats. Methods Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions. Key Results Mean time of gastric emptying after solid meals were significantly different (p