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1.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 41(1): 98-104, 2024 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-38403609

RESUMO

Transcranial magnetic stimulation (TMS), a widely used neuroregulatory technique, has been proven to be effective in treating neurological and psychiatric disorders. The therapeutic effect is closely related to the intracranial electric field caused by TMS, thus accurate measurement of the intracranial electric field generated by TMS is of great significance. However, direct intracranial measurement in human brain faces various technical, safety, ethical and other limitations. Therefore, we have constructed a brain phantom that can simulate the electrical conductivity and anatomical structure of the real brain, in order to replace the clinical trial to achieve intracranial electric field measurement. We selected and prepared suitable conductive materials based on the electrical conductivity of various layers of the real brain tissue, and performed image segmentation, three-dimensional reconstruction and three-dimensional printing processes on each layer of tissue based on magnetic resonance images. The production of each layer of tissue in the brain phantom was completed, and each layer of tissue was combined to form a complete brain phantom. The induced electric field generated by the TMS coil applied to the brain phantom was measured to further verify the conductivity of the brain phantom. Our study provides an effective experimental tool for studying the distribution of intracranial electric fields caused by TMS.


Assuntos
Encéfalo , Estimulação Magnética Transcraniana , Humanos , Encéfalo/fisiologia , Estimulação Magnética Transcraniana/métodos , Cabeça , Mapeamento Encefálico/métodos , Condutividade Elétrica , Campos Eletromagnéticos
2.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 40(3): 401-408, 2023 Jun 25.
Artigo em Zh | MEDLINE | ID: mdl-37380377

RESUMO

In transcranial magnetic stimulation (TMS), the conductivity of brain tissue is obtained by using diffusion tensor imaging (DTI) data processing. However, the specific impact of different processing methods on the induced electric field in the tissue has not been thoroughly studied. In this paper, we first used magnetic resonance image (MRI) data to create a three-dimensional head model, and then estimated the conductivity of gray matter (GM) and white matter (WM) using four conductivity models, namely scalar (SC), direct mapping (DM), volume normalization (VN) and average conductivity (MC), respectively. Isotropic empirical conductivity values were used for the conductivity of other tissues such as the scalp, skull, and cerebrospinal fluid (CSF), and then the TMS simulations were performed when the coil was parallel and perpendicular to the gyrus of the target. When the coil was perpendicular to the gyrus where the target was located, it was easy to get the maximum electric field in the head model. The maximum electric field in the DM model was 45.66% higher than that in the SC model. The results showed that the conductivity component along the electric field direction of which conductivity model was smaller in TMS, the induced electric field in the corresponding domain corresponding to the conductivity model was larger. This study has guiding significance for TMS precise stimulation.


Assuntos
Imagem de Tensor de Difusão , Estimulação Magnética Transcraniana , Condutividade Elétrica , Eletricidade , Couro Cabeludo
3.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 40(5): 1005-1011, 2023 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-37879931

RESUMO

Transcranial electric stimulation (TES) is a non-invasive, economical, and well-tolerated neuromodulation technique. However, traditional TES is a whole-brain stimulation with a small current, which cannot satisfy the need for effectively focused stimulation of deep brain areas in clinical treatment. With the deepening of the clinical application of TES, researchers have constantly investigated new methods for deeper, more intense, and more focused stimulation, especially multi-electrode stimulation represented by high-precision TES and temporal interference stimulation. This paper reviews the stimulation optimization schemes of TES in recent years and further analyzes the characteristics and limitations of existing stimulation methods, aiming to provide a reference for related clinical applications and guide the following research on TES. In addition, this paper proposes the viewpoint of the development direction of TES, especially the direction of optimizing TES for deep brain stimulation, aiming to provide new ideas for subsequent research and application.


Assuntos
Estimulação Encefálica Profunda , Estimulação Transcraniana por Corrente Contínua , Estimulação Transcraniana por Corrente Contínua/métodos , Encéfalo/fisiologia , Cabeça , Estimulação Elétrica/métodos
4.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 40(1): 1-7, 2023 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-36854542

RESUMO

Existing neuroregulatory techniques can achieve precise stimulation of the whole brain or cortex, but high-focus deep brain stimulation has been a technical bottleneck in this field. In this paper, based on the theory of negative permeability emerged in recent years, a simulation model of magnetic replicator is established to study the distribution of the induced electric field in the deep brain and explore the possibility of deep focusing, which is compared with the traditional magnetic stimulation method. Simulation results show that a single magnetic replicator realized remote magnetic source. Under the condition of the same position and compared with the traditional method of stimulating, the former generated smaller induced electric field which sharply reduced with distance. By superposition of the magnetic field replicator, the induced electric field intensity could be increased and the focus could be improved, reducing the number of peripheral wires while guaranteeing good focus. The magnetic replicator model established in this paper provides a new idea for precise deep brain stimulation, which can be combined with neuroregulatory techniques in the future to lay a foundation for clinical application.


Assuntos
Encéfalo , Córtex Cerebral , Simulação por Computador , Eletricidade , Campos Magnéticos
5.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 39(1): 10-18, 2022 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-35231961

RESUMO

Electric field stimulation (EFS) can effectively inhibit local Ca 2+ influx and secondary injury after spinal cord injury (SCI). However, after the EFS, the Ca 2+ in the injured spinal cord restarts and subsequent biochemical reactions are stimulated, which affect the long-term effect of EFS. Polyethylene glycol (PEG) is a hydrophilic polymer material that can promote cell membrane fusion and repair damaged cell membranes. This article aims to study the combined effects of EFS and PEG on the treatment of SCI. Sprague-Dawley (SD) rats were subjected to SCI and then divided into control group (no treatment, n = 10), EFS group (EFS for 30 min, n = 10), PEG group (covered with 50% PEG gelatin sponge for 5 min, n = 10) and combination group (combined treatment of EFS and PEG, n = 10). The measurement of motor evoked potential (MEP), the motor behavior score and spinal cord section fast blue staining were performed at different times after SCI. Eight weeks after the operation, the results showed that the latency difference of MEP, the amplitude difference of MEP and the ratio of cavity area of spinal cords in the combination group were significantly lower than those of the control group, EFS group and PEG group. The motor function score and the ratio of residual nerve tissue area in the spinal cords of the combination group were significantly higher than those in the control group, EFS group and PEG group. The results suggest that the combined treatment can reduce the pathological damage and promote the recovery of motor function in rats after SCI, and the therapeutic effects are significantly better than those of EFS and PEG alone.


Assuntos
Polietilenoglicóis , Traumatismos da Medula Espinal , Animais , Estimulação Elétrica , Polietilenoglicóis/farmacologia , Polietilenoglicóis/uso terapêutico , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/fisiologia , Medula Espinal , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/terapia
6.
J Neurosci Res ; 99(7): 1850-1863, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33847010

RESUMO

The application of electric field stimulation (EFS) can reduce the cation influx after spinal cord injury. However, regenerated cation influx and reestablished injury potential are observed after EFS. Polyethylene glycol (PEG) is popular as an effective cell membrane fusion agent. This study aims to determine the effects of the combination therapy of EFS and PEG in the ex vivo spinal cord after compression. The ex vivo spinal cords of female rats with compression injury were incubated in a double sucrose gap recording chamber (DSGRC) and randomly divided into the following four groups: (1) compression group: compression only, (2) EFS group: EFS for 15 min, (3) PEG group: PEG treatment for 4 min, and (4) EFS + PEG group: EFS for 15 min and PEG treatment for 4 min. The hematoxylin-eosin staining was performed to measure the necrotic area of the spinal cords. The gap potential was detected, and the area under the curve of the gap potential was calculated. The intracellular cation concentration, membrane permeability, and compound action potential were measured and quantified. Results revealed no significant difference in the necrotic areas among different groups, and the compression model of the ex vivo spinal cord in the DSGRC had high consistency and stability. The combination therapy could attenuate cation inflow, promote cell membrane restoration, and promote the functional recovery of the spinal cord conduction after compression in ex vivo spinal cords.


Assuntos
Estimulação Elétrica/métodos , Polietilenoglicóis/farmacologia , Compressão da Medula Espinal/fisiopatologia , Medula Espinal/fisiopatologia , Potenciais de Ação/efeitos dos fármacos , Animais , Terapia Combinada/métodos , Feminino , Condução Nervosa/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Ratos , Ratos Sprague-Dawley , Medula Espinal/efeitos dos fármacos
7.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 38(2): 232-240, 2021 Apr 25.
Artigo em Zh | MEDLINE | ID: mdl-33913282

RESUMO

Spinal cord stimulation (SCS) for pain is usually implanted as an open loop system using unchanged parameters. To avoid the under and over stimulation caused by lead migration, evoked compound action potentials (ECAP) is used as feedback signal to change the stimulating parameters. This study established a simulation model of ECAP recording to investigate the relationship between ECAP component and dorsal column (DC) fiber recruitment. Finite element model of SCS and multi-compartment model of sensory fiber were coupled to calculate the single fiber action potential (SFAP) caused by single fiber in different spinal cord regions. The synthetized ECAP, superimposition of SFAP, could be considered as an index of DC fiber excitation degree, because the position of crests and amplitude of ECAP corresponds to different fiber diameters. When 10% or less DC fibers were excited, the crests corresponded to fibers with large diameters. When 20% or more DC fibers were excited, ECAP showed a slow conduction crest, which corresponded to fibers with small diameters. The amplitude of this slow conduction crest increased as the stimulating intensity increased while the amplitude of the fast conduction crest almost remained unchanged. Therefore, the simulated ECAP signal in this paper could be used to evaluate the degree of excitation of DC fibers. This SCS-ECAP model may provide theoretical basis for future clinical application of close loop SCS base on ECAP.


Assuntos
Estimulação da Medula Espinal , Potenciais de Ação , Simulação por Computador , Estimulação Elétrica , Potenciais Evocados , Medula Espinal
8.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 35(1): 151-155, 2018 02 25.
Artigo em Zh | MEDLINE | ID: mdl-29745615

RESUMO

Bioartificial liver support system (BALSS) provides a new way to treat liver failure and leaves more time for patients who are waiting for liver transplantation. It has detoxification function as well as the human liver, at the same time it can provide nutrition and improve the internal environment inside human body. Bioreactors and hepatocytes with good biological activity are the cores of BALSS which determine the treatment effect. However, in the course of prolonged treatment, the function and activity of hepatocytes might be greatly changed which could influence the efficacy. Therefore, it is very important to detect the status of the hepatocytes in BALSS. This paper presents some common indicators of cell activity, detoxification and synthetic functions, and also introduces the commonly detection methods corresponding to each indicator. Finally, we summarize the application of detection methods of the hepatocyte status in BALSS and discuss its development trend.

9.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 35(4): 564-570, 2018 08 25.
Artigo em Zh | MEDLINE | ID: mdl-30124019

RESUMO

Modified electroconvulsive therapy (MECT) and magnetic seizure therapy (MST) are effective treatments for severe major depression. MECT has better efficacy in the treatment than MST, but it has cognitive and memorial side effects while MST does not. To study the causes of these different outcomes, this study contrasted the electric filed strength and spatial distribution induced by MECT and MST in a realistic human head model. Electric field strength induced by MECT and MST are simulated by the finite element method, which was based on a realistic human head model obtained by magnetic resonance imaging. The electrode configuration of MECT is standard bifrontal stimulation configuration, and the coil configuration of MST is circular. Maps of the ratio of the electric field strength to neural activation threshold are obtained to evaluate the stimulation strength and stimulation focality in brain regions. The stimulation strength induced by MECT is stronger than MST, and the activated region is wider. MECT stimulation strength in gray matter is 17.817 times of that by MST, and MECT stimulation strength in white matter is 23.312 times of that by MST. As well, MECT stimulation strength in hippocampi is 35.162 times of that by MST. More than 99.999% of the brain volume is stimulated at suprathreshold by MECT. However, MST activated only 0.700% of the brain volume. The stimulation strength induced by MECT is stronger than MST, and the activated region is wider may be the reason that MECT has better effectiveness. Nevertheless, the stronger stimulation strength in hippocampi induced by MECT may be the reason that MECT is more likely to give rise to side effects. Based on the results of this study, it is expected that a more accurate clinical quantitative treatment scheme should be studied in the future.

10.
Neural Regen Res ; 17(6): 1318-1323, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34782577

RESUMO

Oscillating field stimulation (OFS) is a potential method for treating spinal cord injury. Although it has been used in spinal cord injury (SCI) therapy in basic and clinical studies, its underlying mechanism and the correlation between its duration and nerve injury repair remain poorly understood. In this study, we established rat models of spinal cord contusion at T10 and then administered 12 weeks of OFS. The results revealed that effectively promotes the recovery of motor function required continuous OFS for more than 6 weeks. The underlying mechanism may be related to the effects of OFS on promoting axon regeneration, inhibiting astrocyte proliferation, and improving the linear arrangement of astrocytes. This study was approved by the Animal Experiments and Experimental Animal Welfare Committee of Capital Medical University (supplemental approval No. AEEI-2021-204) on July 26, 2021.

11.
Brain Topogr ; 23(4): 375-84, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20577795

RESUMO

Recent studies in adults have found consistent contralateral high gamma activities in the sensorimotor cortex during unilateral finger movement. However, no study has reported on this same phenomenon in children. We hypothesized that contralateral high gamma activities also exist in children during unilateral finger movement. Sixty normal children (6-17 years old) were studied with a 275-channel MEG system combined with synthetic aperture magnetometry (SAM). Sixty participants displayed consistently contralateral event-related synchronization (C-ERS) within high gamma band (65-150 Hz) in the primary motor cortices (M1) of both hemispheres. Interestingly, nineteen younger children displayed ipsilateral event-related synchronization (I-ERS) within the high gamma band (65-150 Hz) just during their left finger movement. Both I-ERS and C-ERS were localized in M1. The incidence of I-ERS showed a significant decrease with age. Males had significantly higher odds of having ipsilateral activity compared to females. Noteworthy, high gamma C-ERS appeared consistently, while high gamma I-ERS changed with age. The asymmetrical patterns of neuromagnetic activities in the children's brain might represent the maturational lateralization and/or specialization of motor function. In conclusion, the present results have demonstrated that contralateral high-gamma neuromagnetic activities are potential biomarkers for the accurate localization of the primary motor cortex in children. In addition, the interesting finding of the ipsilateral high-gamma neuromagnetic activities opens a new window for us to understand the developmental changes of the hemispherical functional lateralization in the motor system.


Assuntos
Envelhecimento/fisiologia , Dedos/fisiologia , Magnetoencefalografia , Córtex Motor/fisiologia , Movimento/fisiologia , Adolescente , Criança , Sincronização Cortical , Sinais (Psicologia) , Feminino , Humanos , Modelos Logísticos , Magnetoencefalografia/métodos , Masculino , Córtex Motor/crescimento & desenvolvimento , Oscilometria , Fatores Sexuais
12.
Headache ; 50(6): 1005-16, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20487034

RESUMO

OBJECTIVE: To investigate the functional abnormalities of the motor cortices in children with migraine using magnetoencephalography (MEG) and a finger-tapping task. BACKGROUND: Cortical hyperexcitability has been reported in adults with migraine using MEG. Many children with migraine report difficulty with motor functioning. There is no report on motor-evoked magnetic activation in children with migraine using MEG and the latest signal processing methods. METHODS: Ten children with migraine (all female, 9 right-handed and 1 left-handed, aged 13-17 years) and 10 age- and gender-matched healthy children were studied with a 275-channel MEG system. After hearing a unilateral, randomly presented sound cue (500 Hz, 30 milliseconds square tone), each subject immediately performed a brisk index finger tapping with either the right or the left index finger. The auditory stimuli consisted of 200 trials of square tone, 100 trials per ear, randomly distributed. The latency and amplitude of neuromagnetic responses were analyzed with averaged waveforms. Neuromagnetic sources were estimated using synthetic aperture magnetometry (SAM). SAM images were normalized for each participant for group comparison. RESULTS: In comparison with healthy children, children with migraine had prolonged latency of motor-evoked magnetic response in the right hemispheres during left finger movement (62.33 +/- 34.55 milliseconds vs 34.9 +/- 17.29 milliseconds, P < .05). In addition, children with migraine had stronger activation in the motor cortex during right finger movement (8097.46 +/- 5168.99 vs 4697.54 +/- 3194.74, P < .05). CONCLUSIONS: The results suggest that there are neurophysiological changes in the motor cortices of children with migraine that can be measured with neuromagnetic imaging techniques. The findings expand the ability to study the cerebral mechanisms of migraine using MEG and may facilitate the development of new therapeutic strategies in migraine treatment via alterations in cortical excitability.


Assuntos
Transtornos de Enxaqueca/fisiopatologia , Córtex Motor/fisiopatologia , Movimento/fisiologia , Adolescente , Mapeamento Encefálico , Feminino , Dedos , Lateralidade Funcional/fisiologia , Humanos , Magnetoencefalografia , Processamento de Sinais Assistido por Computador
13.
Bioelectromagnetics ; 30(8): 663-8, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19496105

RESUMO

The effects of extremely low frequency (ELF) magnetic fields on membrane F(0)F(1)-ATPase activity have been studied. When the F(0)F(1)-ATPase was exposed to 60 Hz magnetic fields of different magnetic intensities, 0.3 and 0.5 mT magnetic fields enhanced the hydrolysis activity, whereas 0.1 mT exposure caused no significant changes. Even if the F(0)F(1)-ATPase was inhibited by N,N-dicyclohexylcarbodiimide, its hydrolysis activity was enhanced by a 0.5 mT 60 Hz magnetic field. Moreover, when the chromatophores which were labeled with F-DHPE were exposed to a 0.5 mT, 60 Hz magnetic field, it was found that the pH of the outer membrane of the chromatophore was unchanged, which suggested that the magnetic fields used in this work did not affect the activity of F0. Taken together, our results show that the effects of magnetic fields on the hydrolysis activity of the membrane F(0)F(1)-ATPases were dependent on magnetic intensity and the threshold intensity is between 0.1 and 0.3 mT, and suggested that the F1 part of F(0)F(1)-ATPase may be an end-point affected by magnetic fields.


Assuntos
Magnetismo , ATPases Translocadoras de Prótons/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise
14.
Epileptic Disord ; 11(2): 113-25, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19473946

RESUMO

PURPOSE: Invasive intracranial recordings have suggested that high-frequency oscillation is involved in epileptogenesis and is highly localized to epileptogenic zones. The aim of the present study is to characterize the frequency and spatial patterns of high-frequency brain signals in childhood epilepsy using a non-invasive technology. METHODS: Thirty children with clinically diagnosed epilepsy were studied using a whole head magnetoencephalography (MEG) system. MEG data were digitized at 4,000 Hz. The frequency and spatial characteristics of high-frequency neuromagnetic signals were analyzed using continuous wavelet transform and beamformer. Three-dimensional magnetic resonance imaging (MRI) was obtained for each patient to localize magnetic sources. RESULTS: Twenty-six patients showed high-frequency (100-1,000 Hz) components (26/30, 86%). Nineteen patients showed more than one high-frequency component (19/30, 63%). The frequency range of high-frequency components varied across patients. The highest frequency band was identified around 910 Hz. The loci of high-frequency epileptic activities were concordant with the lesions identified by magnetic resonance imaging for 21 patients (21/30, 70%). The MEG source localizations of high-frequency components were found to be concordant with intracranial recordings for nine of the eleven patients who underwent epilepsy surgery (9/11, 82%). CONCLUSION: The results have demonstrated that childhood epilepsy was associated with high-frequency epileptic activity in a wide frequency range. The concordance of MEG source localization, MRI and intracranial recordings suggests that measurement of high-frequency neuromagnetic signals might provide a novel approach for clinical management of childhood epilepsy.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/patologia , Encéfalo/fisiopatologia , Eletroencefalografia , Epilepsia/diagnóstico , Imageamento por Ressonância Magnética , Magnetoencefalografia , Adolescente , Criança , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Epilepsia/patologia , Epilepsia/fisiopatologia , Feminino , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Magnetoencefalografia/métodos , Masculino
15.
Neural Regen Res ; 13(5): 869-876, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29863018

RESUMO

Our previous study revealed that early application of electrical field stimulation (EFS) with the anode at the lesion and the cathode distal to the lesion reduced injury potential, inhibited secondary injury and was neuroprotective in the dorsal corticospinal tract after spinal cord injury (SCI). The objective of this study was to further evaluate the effect of EFS on protection of anterior horn motoneurons and their target musculature after SCI and its mechanism. Rats were randomized into three equal groups. The EFS group received EFS for 30 minutes immediately after injury at T10. SCI group rats were only subjected to SCI and sham group rats were only subjected to laminectomy. Luxol fast blue staining demonstrated that spinal cord tissue in the injury center was better protected; cross-sectional area and perimeter of injured tissue were significantly smaller in the EFS group than in the SCI group. Immunofluorescence and transmission electron microscopy showed that the number of spinal cord anterior horn motoneurons was greater and the number of abnormal neurons reduced in the EFS group compared with the SCI group. Wet weight and cross-sectional area of vastus lateralis muscles were smaller in the SCI group to in the sham group. However, EFS improved muscle atrophy and behavioral examination showed that EFS significantly increased the angle in the inclined plane test and Tarlov's motor grading score. The above results confirm that early EFS can effectively impede spinal cord anterior horn motoneuron loss, promote motor function recovery and reduce muscle atrophy in rats after SCI.

16.
Biomed Res Int ; 2018: 7456898, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29992160

RESUMO

Renal dysfunction is one of the most common complications of liver cirrhosis and is associated with increased morbidity and mortality. However, no available technology can simultaneously support liver and renal function in these patients. The aim of this study was to evaluate the safety and efficacy of an artificial liver and renal support system in cynomolgus monkeys with surgery-induced ARF. The ARF model was established by ligature of bilateral renal arteries in eight cynomolgus monkeys, which were randomly divided into a treatment group (n = 4) and control group (n = 4). Biochemical indexes were determined before and after surgery. Blood endotoxin levels, biochemical indexes, and bacterial cultures were assessed at 0, 3, and 6 h during treatment. System pressures and vital signs were recorded at 1 h intervals. Pathological examination was performed after death. ARF was successfully established, based on significant elevation of biochemical indexes and pathological examination. The treatment group had significantly reduced biochemical indexes relative to the control group. Measurement of blood endotoxins and aerobic and anaerobic bacteria cultures indicated no bacterial growth. The system pressures and vital signs were stable during treatment. The results indicate that our support system for the treatment of cynomolgus monkeys with surgery-induced acute renal failure is safe and effective.


Assuntos
Injúria Renal Aguda/terapia , Fígado Artificial , Injúria Renal Aguda/etiologia , Animais , Modelos Animais de Doenças , Feminino , Humanos , Cirrose Hepática/complicações , Macaca fascicularis , Masculino
17.
Neurosci Lett ; 412(2): 143-7, 2007 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-17123730

RESUMO

This study aimed to determine the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on electroencephalograms (EEGs) of rats. Fifteen Sprague-Dawley rats were subject to 100 pulses of 0.5 Hz rTMS, or sham stimulation. EEGs were recorded before stimulation and within 1 min after rTMS or sham stimulation. Estimates of the EEG correlation dimension (D(2)) and power spectra were calculated. Results show that the D(2) reduced significantly after low-frequency rTMS, but not after sham stimulation. Mean absolute power (MAP) of the gamma band and relative power (RP) of the beta and gamma bands reduce markedly after low-frequency rTMS, but there are no changes with sham stimulation. These results indicate that low-frequency rTMS could affect cortical activities significantly, but effects were markedly different from those of high-frequency rTMS.


Assuntos
Encéfalo/fisiologia , Encéfalo/efeitos da radiação , Eletroencefalografia/efeitos da radiação , Campos Eletromagnéticos , Estimulação Magnética Transcraniana , Potenciais de Ação/fisiologia , Potenciais de Ação/efeitos da radiação , Animais , Masculino , Neurônios/fisiologia , Neurônios/efeitos da radiação , Ratos , Ratos Sprague-Dawley
18.
Zhonghua Wai Ke Za Zhi ; 45(24): 1685-7, 2007 Dec 15.
Artigo em Zh | MEDLINE | ID: mdl-18476527

RESUMO

OBJECTIVE: To analyze the effect of low frequency transcranial magnetic stimulation (LF-TMS) on changing neuropeptide-Y (NPY) expression and apoptosis of hippocampus neurons in epilepsy rats induced by pilocarpine (PLO). METHODS: Thirty male Sprague Dawley rats (240 g +/- 20 g) were randomly divided into 2 groups. I group simply celiac injected pilocarpine. II group celiac injected PLO after LF-TMS. Pathological item included HE staining, NPY immunohistochemical staining and apoptosis staining. RESULTS: HE staining revealed neurons of hippocampus were obviously death and cell's structure was destroyed in PLO group. The PLO + LF-TMS group was less injured and destroyed. Using One-Way ANOVA, NPY immunohistochemical staining shown the positive cell number was increased at all areas of hippocampus in PLO group contrasting with the low positive cell number in the PLO + LF-TMS group. In PLO group the number of apoptosis cell at hippocampus areas was significant higher than the PLO + LF-TMS group. CONCLUSIONS: Using the PLO evoked epilepsy model, LF-TMS alleviated neurons injury at hippocampus area, so LF-TMS might playing an important role in resisting the progressing of epilepsy. The positive cell number of NPY increased at all areas of hippocampus, which indicated the close relation between NPY and epilepsy. NPY might have some function on resisting epilepsy.


Assuntos
Apoptose , Epilepsia do Lobo Temporal/terapia , Neurônios/patologia , Neuropeptídeo Y/metabolismo , Estimulação Magnética Transcraniana/métodos , Animais , Modelos Animais de Doenças , Epilepsia do Lobo Temporal/induzido quimicamente , Epilepsia do Lobo Temporal/metabolismo , Epilepsia do Lobo Temporal/patologia , Hipocampo/metabolismo , Hipocampo/patologia , Masculino , Neurônios/metabolismo , Pilocarpina/toxicidade , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
19.
Artigo em Zh | MEDLINE | ID: mdl-18230298

RESUMO

OBJECTIVE: To investigate the effect of the extremely low frequency pulsed electromagnetic field (PEMF) on the proliferation and differentiation of osteoblast-like cells. METHODS: The MC3T3-E1 cell and the primary osteoblast cell derived from 2-day-old Sprague Dawley (SD) rat calvaria were exposed to PEMF with a magnetic flux density of 1.55 mT at 48 Hz for 24 or 48 h. MTS was applied to analyze cell proliferation and flow cytometry to detect cell cycle. The intracellular alkaline phosphatase (ALP) activity was measured by colorimetry. RESULTS: PEMF of 1.55 mT at 48 Hz decreased significantly the cell percentage of S or G(2)M phase (P < 0.05), but did not affect cell number of MC3T3-E1 cells. Although the number of the primary osteoblast cells did not alter by MTS assay after exposure to PEMF for 24 h continuously, the cell percentage of G(2)M phase increased significantly (P < 0.01). When the culture time extended to 48 h, the cell number increased greatly (P < 0.01) and the cell percentage of G(2)M phase decreased significantly despite of the exposure type (P < 0.01). After the primary osteoblast cells were exposed to PEMF for 24 h continuously, the ALP activity decreased significantly (P < 0.05), whereas it increased significantly after exposure to PEMF for 48 h continuously (P < 0.05). CONCLUSION: PEMF of 1.55 mT at 48 Hz does not affect proliferation and differentiation of MC3T3-E1 cell, but it promotes proliferation of primary osteoblast cell, inhibits differentiation at proliferation stage and promotes differentiation at differentiation stage of primary osteoblast cell.


Assuntos
Campos Eletromagnéticos/efeitos adversos , Osteoblastos/efeitos da radiação , Animais , Diferenciação Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Células Cultivadas , Relação Dose-Resposta à Radiação , Camundongos , Osteoblastos/citologia , Osteoblastos/metabolismo , Ratos , Ratos Sprague-Dawley
20.
Exp Ther Med ; 13(5): 2247-2254, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28565833

RESUMO

Transcranial magnetic stimulation (TMS) is a method of noninvasive brain stimulation that causes neuromodulation by activating neurons or changing excitability in a certain brain area. Considering the known effects of TMS and the pathophysiology of traumatic brain injury (TBI), TMS was proposed to have potential for treating this condition. Moderate TBI was induced in adult male Sprague Dawley rats using Feeney's weight-dropping method. Injured rats were divided into a TMS group and a control group. Repetitive TMS (rTMS) was administered to rats in the TMS group from post-TBI day 2. At post-TBI days 7, 14 and 28, three or four of the rats were sacrificed, and harvested brains were embedded in paraffin and sectioned. Sections were then treated with hematoxylin and eosin and immunohistochemical staining. Three rats from each group underwent fludeoxyglucose F 18 micro-positron emission tomography scanning on post-TBI day 2 and 13. The unexpected mortality rate after injury was lower in the TMS group than in the control group. The modified neurological severity score of the TMS group was lower compared with the control group at post-TBI day 14. According to the results of hematoxylin eosin staining, relative cerebral parenchyma loss was lower at post-TBI day 28 in the TMS group compared with the control group. However, the aforementioned differences were not found to be statistically significant. There was also no significant difference in glucose metabolism between the two groups. According to immunohistochemical staining, the TMS group showed a significantly higher level of proliferation (indicated by bromodeoxyuridine) in the subventricular zone, as compared with the control group (P<0.05). A significantly higher rate of neuron survival at day 28 (P<0.05; indicated by NeuN) and a significantly reduced rate of apoptosis at days 7 and 14 (P<0.05; indicated by caspase-3) were observed in the perilesional zone of the TMS group, as compared with the control group. The current findings suggest that high-frequency rTMS may promote neurogenesis and provide a basis for further studies in this area.

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