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La estimulación magnética transcraneal (EMT) es una técnica no invasiva que consiste en la utilización de campos magnéticos para estimular a las neuronas de la corteza cerebral. Si bien la electricidad se ha pretendido emplear previamente en el campo de la medicina, la historia de la EMT se remonta al descubrimiento de la inducción electromagnética, por Faraday, en el siglo XIX. Sin embargo, no fue hasta la década de 1980 cuando Anthony Barker, en la Universidad de Sheffield, desarrolló el primer dispositivo de EMT. La EMT funciona mediante una bobina colocada en el cuero cabelludo, la cual produce un campo magnético que puede atravesar el cráneo y estimular las neuronas corticales. La intensidad y la frecuencia del campo magnético pueden ajustarse para dirigirse a zonas específicas del cerebro y producir efectos excitatorios e inhibitorios. Los principios de la EMT se basan en el concepto de neuroplasticidad, que se refiere a la capacidad del cerebro para cambiar y adaptarse en respuesta a nuevas experiencias y estímulos. Al estimular las neuronas del cerebro con la EMT, es posible inducir cambios en la actividad neuronal y la conectividad, lo que a su vez puede provocar cambios cognitivos y en el estado de ánimo.
Transcranial magnetic stimulation (TMS) is a noninvasive technique that uses magnetic fields to stimulate neurons in the cerebral cortex. While electricity has previously been intended to be used in the medical field, the history of TMS dates back to the discovery of electromagnetic induction by Faraday in the 19th century. However, it was not until the 1980s when Anthony Barker developed the first TMS device at the University of Sheffield. TMS works by means of a coil placed against the scalp, thereby producing a magnetic field. This magnetic field can pass through the skull and stimulate cortical neurons. The intensity and frequency of the magnetic field can be adjusted to target specific areas of the brain and produce excitatory and inhibitory effects. The principles of TMS are based on the concept of neuroplasticity, which refers to the brain's ability to change and adapt in response to new experiences and stimuli. By stimulating neurons in the brain with TMS, it is possible to cause changes in neuronal activity and connectivity, which in turn can lead to cognitive and mood changes.
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Abstract Background: There have been scattered reports indicating the possibility that applied magnetic fields can lower human blood viscosity, which has been considered as encouraging for decreasing blood pressure as a result of greater fluidity. Additional motivation comes from partial studies in animals showing some response of vascular variables to magnetic fields. Recently developed FeNbB magnets enable topical application to appropriate sites of much stronger permanent magnetic fields than previously available. Objectives: To establish whether powerful magnetic fields permanently applied along important arteries of the human body can lower blood pressure and, if so, to what extent. Methods: Ambulatory blood pressure tests were performed on 70 patients, half of them wearing real magnets, while the other 35 patients were wearing a similar placebo. Magnets or placebo devices were assigned at random. Each patient underwent two consecutive ambulatory 24-hour blood pressure (BP) tests; the first without a device and the second one with a device. Results: Results were compiled and analyzed only after the last measurement was completed. Individual responses, average values, standard deviations, information content, and Student's t test showed that no difference was found between measurements in either group. Conclusion: Permanent strong magnetic fields applied along the main arteries of the human body do not alter blood pressure. This was observed both in statistical terms and in individuals as well.
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Resumen Introducción: la demanda de energía eléctrica va de la mano del aumento de la población, por lo que para satisfacerla se debe asegurar la capacidad de generación eléctrica, esto incentivaría la construcción de plantas térmicas; aumentando los trabajadores expuestos a los peligros de termoeléctricas. Esta revisión tiene como fin identificar cuáles riesgos y peligros en termoeléctricas han sido estudiadas en el mundo durante el periodo 20072017. Objetivo: identificar, a través de una revisión bibliográfica, los principales peligros a que están expuestos los trabajadores de termoeléctricas. Materiales y métodos: se realizó una revisión sistemática teniendo en cuenta las recomendaciones de la guía PRISMA, se tuvieron en cuenta estudios acerca de los factores de riesgos a los que se exponen el personal de operaciones de centrales térmicas; para la búsqueda se establecieron dos algoritmos con descriptores DeCS y MeSH en las bases de datos Scopus, Pubmed, Scient Direct y Google académico, encontrándose 21 publicaciones que cumplían con los criterios de inclusión. Resultados: los peligros más relevantes para los trabajadores en termoeléctricas son físicos, ergonómicos, químicos, biológicos y psicosociales. Conclusión: los trabajadores de termoeléctricas están expuestos a varios peligros que pueden aumentar el riesgo de ocasionarles enfermedades respiratorias, musculoesqueleticas, pérdida de capacidad auditiva, cáncer, leucemia y su variedad, pericarditis, Alzheimer, Parkinson, daño genético y celular; también se pudo evidenciar que el efecto en la salud por exposición en campos magnéticos requiere de estudios de más profundidad.
Abstract Introduction: the demand for electric power, goes hand in hand with the population increasing, to satisfy it, the power generation capacity must be ensured, this would encourage the construction of thermal plants; increasing the exposition of workers to the thermoelectric plant dangers. This review aims to identify which risks and dangers in thermoelectric plants have been studied in the world for the period 2007-2017. Objective: identify the main hazards to which thermoelectric workers are exposed through a literature review. Materials and methods: a systematic review was carried out taking into account the recommendations of the PRISMA guide, studies were taken into account about the risk factors to which thermal power plant operations personnel are exposed; Two algorithms with DeCS and MeSH descriptors were established in the Scopus, PubMed, Scient Direct and Google academic databases, with 21 publications meeting the inclusion criteria. Results: the most relevant hazards for thermoelectric workers are physical, ergonomic, chemical, biological and psychosocial. Conclusion: thermoelectric workers are exposed to various hazards that may increase the risk of respiratory, musculoskeletal, hearing loss, cancer, leukemia and its variety, pericarditis, Alzheimer's, Parkinson's, genetic and cellular damage; It could also be evidenced that the effect on health by exposure in magnetic fields requires more in-depth studies.
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Humans , Power Plants , Occupational Risks , Risk Factors , Morbidity , Occupational Health , Greenhouse Gases , Magnetic FieldsABSTRACT
Los neonatos pretérminos nacen con inmadurez en los órganos, lo que lleva al compromiso del sistema inmunológico. Los campos electromagnéticos afectan la producción de melatonina a niveles bajos de exposición. Estos niños necesitan equipamiento médico las 24 horas del día para su recuperación, por lo que están expuestos a los campos magnéticos durante todo el tiempo que se encuentren en la Unidad de Terapia Intensiva. El objetivo fue medir los niveles de campo magnético que se generan alrededor de cada una de las incubadoras utilizando un gaussímetro y comparar los resultados con las recomendaciones de la Comisión Internacional para la Protección contra las Radiaciones No Ionizantes de 2010 y la norma de la International Electrotechnical Commission (IEC) IEC 60601-1-2:2004. En 11 neonatos internados, los valores de radiación se encontraban dentro de los recomendados, pero existía interferencia electromagnética por problemas de disposición de los equipos en el área.
Preterm infants are born with immature organs, thus affecting the immune system. Electromagnetic fields influence melatonin production with low exposure levels. These infants require medical equipment 24/7 to recover, so they are constantly exposed to magnetic fields during their stay in the Intensive Care Unit. Our objective was to measure magnetic field levels generated around each incubator using a gauss meter and compare our results to the 2010 recommendations by the International Commission on Non-Ionizing Radiation Protection and the IEC 60601-1-2:2004 standard by the International Electrotechnical Commission (IEC). Among 11 hospitalized newborn infants, radiation was found within the recommended limits, but there was electromagnetic interference resulting from medical equipment layout problems in the unit.
Subject(s)
Humans , Male , Female , Infant, Newborn , Magnetic Fields/adverse effects , Infant, Premature , Equipment and Supplies , Water Level Measurement/analysis , Incubators , Intensive Care Units , Maximum Allowable Concentration , MelatoninABSTRACT
Objective To observe the clinical efficacy and safety of Yishen Huoxue Decoction combined with low-frequency pulse magnetic fields (PEMFs) for treatment of hemiplegia with osteoporosis (OP). Methods Totally 144 patients were divided into TCM group and control group with randomized parallel controlled method, with 72 cases in each group. Patients in control group were treated with Western routine therapy, rehabilitation training, PEMFs (putting the magnetic head on the back, five times every week, 20-30 minutes each time). On the basis of control group,TCM group received Yishen Huoxue Decoction,one dosage per day,twice a day,orally.The therapeutic course for both groups was 6 weeks. The Fugl-Meyer assessment (FMA), Barthel index (MBI), NIH stroke scale (NIHSS), and visual analogue scale (VAS) before and after treatment were observed in the two groups of patients. Bone mineral density (BMD) was measured. Blood calcium, serum phosphorus, osteocalcin (BGP) content, type 1 procollagen amino-terminal peptide (P1NP), alkaline phosphatase (BALP) were tested. Safety was tested and adverse reactions were observed. Results Compared with before treatment, the scores of FMA, MBI, NIHSS and VAS improved in both groups (P<0.05); the scores of FMA, NIHSS and VAS in the TCM group were significantly improved than the control group after treatment (P<0.05). Compared with before treatment, the levels of BMD, bone metabolic index were improved in both groups (P<0.05). The levels of BMD, BGP, BALP in the TCM group were better than the control group (P<0.05). There was no abnormality in blood routine, liver and kidney function in the 2 groups after treatment, and no obvious adverse reactions were observed. Conclusion Yishen Huoxue Decoction combined with PEMFs can enhance the motor function, improve the neurological deficit symptoms and decrease the pain in hemiplegia patients with OP, and the bone metabolism.
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Objective To observe any effect of low-frequency transcranial magnetic stimulation (rTMS) on the sleep and mood of elderly insomniacs.Methods Thirty-four elderly insomniacs were divided randomly into an experiment group (n =18) and a control group (n =16).The experiment group received rTMS of the right dorsolateral prefrontal cortex,while the control group was given alternating magnetic field stimulation at the same site.Before and after 4 weeks of the treatments,all of the subjects were assessed using the Pittsburgh sleep quality index (PSQI),the Hamilton anxiety scale (HAMA) and the Hamilton depression scale (HAMD).They were also assessed with those instruments omitting the sleep items in order to reduce the possible impact of any sleep changes on the HAMA and HAMD scores.Results Before the treatment there were no significant differences in the groups' average PSQI,HAMA and HAMD scores.After 4 weeks all the measurements in both groups had decreased significantly,with the experimental group's averages significantly lower than those of the control group.Conclusions rTMS treatment is more effective than alternating magnetic field treatment for the elderly with insomnia,significantly improving their sleep and mood.
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Objective@#To investigate the influence of extremely low-frequency magnetic field on periodical expression of cryptochrome (Cry) gene in mouse embryonic fibroblast NIH3T3 cells.@*Methods@#The NIH3T3 cells were divided into magnetic field group and sham-exposure group. The NIH3T3 cells in the magnetic field group were stimulated by horse serum and then exposed to an extremely low-frequency magnetic field (50 Hz and 0.3 mT) for 48 hours, and those in the sham-exposure group were also stimulated by horse serum and then exposed to a coil for 48 hours. The NIH3T3 cells were collected, total RNA was extracted, and cDNA was obtained via reverse transcription. Real-time fluorescent quantitative RT-PCR was used to measure the changes in transcription cycles of Cry and Period genes in both groups.@*Results@#There was no significant difference in the proliferation rate at 0, 12, 24, and 48 hours of exposure between the two groups (P>0.05) . Both sham-exposure group and magnetic field group showed a rhythmic change in the expression of Cry gene, and compared with the sham-exposure group, the magnetic field group had a significantly shortened circadian rhythm of Cry gene in NIH3T3 cells (t=2.57, P<0.05) . Both groups had rhythmic and periodical expression of Period gene and there was no significant difference between the two groups (t=0.70, P>0.05) .@*Conclusion@#Extremely low-frequency magnetic field can significantly shorten the circadian rhythm of Cry gene in mouse embryonic fibroblasts, while there is no significant change in the circadian rhythm of Period gene.
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Inserido no paradigma da transdisciplinaridade, o presente trabalho foi desenvolvido em etapas, com os seguintes objetivos: a) Construir um dispositivo com base de metal não magnético para ímãs permanentes, visando à geração de um Campo Magnético Estático (CME) ou de um Campo Magnético Compensado (CMC); b) Expor culturas de células mesenquimais a um CME e a um CMC, ou a nenhum campo (controle); c) Analisar a influência destes campos na viabilidade e proliferação celular e nos casos em que houve alteração em pelo menos um destes parâmetros, utilizar a análise proteômica como ferramenta para a compreensão dos mecanismos envolvidos. O dispositivo foi construído utilizando aço inoxidável, capaz de gerar dois tipos de Campos Magnéticos: Compensado (CMC) com intensidade de aproximadamente 0 mT e Estático (CME) com intensidade média de 165 mT. Estes campos foram aplicados a culturas de células mesenquimais de medula óssea de camundongos AJ (MSC/AJ), nos períodos de 0, 24, 48, 72 e 96 h (CMC) e 24 h (CME). Os efeitos sobre a proliferação e a viabilidade foram avaliados por método de contagem manual de células com marcação por azul de tripan. A análise proteômica foi realizada para os experimentos com CMC, com o objetivo de descrever as proteínas envolvidas nas alterações encontradas. A exposição ao CMC tendeu a reduzir a proliferação das células de medula óssea MSC/AJ em relação ao controle em 96 h, porém sem diferença significativa, o que poderia estar relacionado a proteínas que inibem a transcrição, como a Forkhead box protein P2 Foxp2. Este mesmo campo aumentou a viabilidade celular em relação ao baseline para todos os tempos experimentais, o que poderia estar relacionado a proteínas relacionadas à ligação ao Ca+2. Esses mecanismos, entretanto, precisam ser estudados mais profundamente para que possam ser comprovados ou não. Já a exposição ao CME levou a uma tendência à diminuição da proliferação e viabilidade celular em relação ao grupo controle, embora sem diferenças significativas, provavelmente por conta do tamanho amostral e tempo de avaliação (24 h).(AU)
Inserted in the transdisciplinarity paradigm, the present work was developed by steps with the following aims: a) To build a device of non-magnetic metal to hold permanent magnets for the generation of a Static Magnetic Field (SMF) or a Compensated Magnetic Field (CMF); b) To expose mesenchimal cells to the SMF and to CMF or to none of the fields (control); c) To analyze the influence of these fields on cell viability and cell proliferation and in the case where it occurred alteration in at least one of these parameters, to use proteomics as a tool for the comprehension of the involved mechanisms. The device was built in stainless steel, able to generate two kinds of Magnetic Fields: Compesated (CMF) with an intensity of nearly zero mT and Static (SMF) with a mean intensity of 165 mT. These fields were applied to bone marrow mesenchimal cell cultures from AJ mice (MSC/AJ), for 0, 24, 48, 72 and 96 h (CMF) and 24 h (SMF) periods. The effects on the proliferation and viability were assessed by tripan blue dying and manual counting of the cells. Proteomics was done for the experiments with CMF, aiming to describe the involved proteins on found alterations. The exposition to CMF tends to reduce the bone marrow cell proliferation of MSC/AJ in relation to control in 96 h, but with no significant difference, which may be related to proteins that inhibit the transcription, like Forkhead box protein P2 Foxp2. This very field raised the cell viability in relation to the baseline for all the experimental times that could be related to proteins connected to Ca2+ binding. However, these mechanisms need more experiments, so they can be confirmed or not. The exposition to the SMF tends to decrease both cell proliferation and viability in relation to the control group, although with no significant difference, probably because of the sample number and the exposition time (24h).(AU)
Subject(s)
Animals , Male , Mice , Cell Proliferation/physiology , Magnetic Fields , Mesenchymal Stem Cells/physiology , Cell Count , Cell Survival/physiology , Cells, Cultured , Chromatography, Liquid , Mass Spectrometry , Reference Values , Reproducibility of Results , Time FactorsABSTRACT
Abstract Introduction Ongoing research in the use of electromagnetic stimulation as coadjuvant in fracture healing has led the authors to begin generating computer models in order to predict cellular growth changes when cells are electromagnetically stimulated. By generating these models, scientists will be able to better understand how electromagnetic fields affect cellular development. The experimental design integrated a cellular culture bioreactor along with an external magnetic stimulation system, which allowed for dermal models to be exposed to controlled magnetic fields. Methods Initially, it was necessary to analyze the static growth of Normal Human Skin Fibroblast (NHSF) cells when they were exposed to Extremely Low Frequency – Electromagnetic Fields (ELF-EMFs). Using optimal conditions for the NHSF culture, from stimulation signal to scaffolding material, we were able to perform the dynamic flow stimulation experiments. Results The following systems were developed: (1) a bioreactor aimed at cellular tissue culture, and (2) Helmholtz coils capable of generating stimulation signals for the cultured tissue. The authors were able to appreciate the quantified values of cellular density diluted in all the experiment samples that were taken and overall, the irradiated samples displayed an average increase of 53% higher cellular density for the same amount of initial cellular seeding when the cells were exposed to a 1 mT, 60 Hz magnetic field signal. Conclusion ELF-EMF’s indeed alter NHSF cell growth rates and it is the challenge of the authors to continue investigating what cellular mechanisms are altered when cells are exposed to ELF-EMF’s.
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PURPOSE: Toxicity of mucosa is one of the major concerns of radiotherapy (RT), when a target tumor is located near a mucosal lined organ. Energy of photon RT is transferred primarily by secondary electrons. If these secondary electrons could be removed in an internal cavity of mucosal lined organ, the mucosa will be spared without compromising the target tumor dose. The purpose of this study was to present a RT dose reduction in near target inner-surface (NTIS) of internal cavity, using Lorentz force of magnetic field. MATERIALS AND METHODS: Tissue equivalent phantoms, composed with a cylinder shaped internal cavity, and adjacent a target tumor part, were developed. The phantoms were irradiated using 6 MV photon beam, with or without 0.3 T of perpendicular magnetic field. Two experimental models were developed: single beam model (SBM) to analyze central axis dose distributions and multiple beam model (MBM) to simulate a clinical case of prostate cancer with rectum. RT dose of NTIS of internal cavity and target tumor area (TTA) were measured. RESULTS: With magnetic field applied, bending effect of dose distribution was visualized. The depth dose distribution of SBM showed 28.1% dose reduction of NTIS and little difference in dose of TTA with magnetic field. In MBM, cross-sectional dose of NTIS was reduced by 33.1% with magnetic field, while TTA dose were the same, irrespective of magnetic field. CONCLUSION: RT dose of mucosal lined organ, located near treatment target, could be modulated by perpendicular magnetic field.
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Axis, Cervical Vertebra , Magnetic Fields , Models, Theoretical , Mucous Membrane , Prostatic Neoplasms , Radiation Injuries , Radiotherapy , RectumABSTRACT
Aims: This report is the first study of the possible relationship between extremely low frequency (50-60 Hz, ELF) magnetic field (MF) exposure and severe cognitive dysfunction. Earlier studies investigated the relationships between MF occupational exposure and Alzheimer’s disease (AD) or dementia. These studies had mixed results, depending upon whether the diagnosis of AD or dementia was performed by experts and upon the methodology used to classify MF exposure. Study Design: Population-based case-control. Place and Duration of Study: Neurology and Preventive Medicine, Keck School of Medicine, University of Southern California, 2 years. Methodology: The study population consisted of 3050 Mexican Americans, aged 65+, enrolled in Phase 1 of the Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE) study. Mini-Mental State Exam (MMSE) results, primary occupational history, and other data were collected. Severe cognitive dysfunction was defined as an MMSE score below 10. The MF exposure methodology developed and used in earlier studies was used. Results: Univariate odds ratios (OR) were 3.4 (P< .03; 95% CI: 1.3-8.9) for high and 1.7 (P=.27; 95% CI: 0.7-4.1) for medium or high (M/H) MF occupations. In multivariate main effects models, the results were similar. When interaction terms were allowed in the models, the interactions between M/H or high occupational MF exposure and smoking history or age group were statistically significant, depending upon whether two (65-74, 75+) or three (65-74, 75-84, 85+) age groups were considered, respectively. When the analyses were limited to subjects aged 75+, the interactions between M/H or high MF occupations and a positive smoking history were statistically significant. Conclusion: The results of this study indicate that working in an occupation with high or M/H MF exposure may increase the risk of severe cognitive dysfunction. Smoking and older age may increase the deleterious effect of MF exposure.
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PURPOSE: The accuracy of the automated external defibrillator (AED) is susceptible to environmental factors such as vibration, motion artifacts, and electromagnetic interference (EMI). The purpose of this study was to evaluate whether the EMI produced by an electric mattress can affect the performance of AEDs. METHODS: Four commercially available AEDs were evaluated under four ECG rhythm settings (normal sinus rhythm, asystole, ventricular fibrillation, and ventricular tachycardia) with or without an electric mattress. The sensitivity, specificity, positive predictable value, negative predictable value, and accuracy of AEDs were calculated to differentiate shockable from nonshockable rhythms. Times required to interpret the ECGs were checked with and without an electric mattress. RESULTS: A total of 320 tests were recorded, and each AED was tested a total of 80 times. Depending on the AED model used on an electric mattress, sensitivity ranged from 55% to 90% with a specificity of 100%, and accuracy ranged from 77.5% to 95%. For some AEDs, sensitivity was reduced compared to the control. Although there was no significant difference in times required to interpret ECG signals with or without an electric mattress, some AEDs detected a relatively small interference as motion artifacts when an electric mattress was used. All recorded ECG rhythms on an electric mattress showed baseline artifacts and these artifacts lessened with increasing distance from an electric mattress. CONCLUSION: This study suggests that an electric mattress could affect the shockable rhythm performance of some AEDs. Electromagnetic interference generated by an electric mattress could interfere with the ability of some commercial AEDs to correctly interpret stimulated ECG rhythms and provide appropriate defibrillation.
Subject(s)
Artifacts , Defibrillators , Electrocardiography , Heart Arrest , Magnetic Fields , Magnets , Sensitivity and Specificity , Ventricular Fibrillation , VibrationABSTRACT
PURPOSE: The accuracy of the automated external defibrillator (AED) is susceptible to environmental factors such as vibration, motion artifacts, and electromagnetic interference (EMI). The purpose of this study was to evaluate whether the EMI produced by an electric mattress can affect the performance of AEDs. METHODS: Four commercially available AEDs were evaluated under four ECG rhythm settings (normal sinus rhythm, asystole, ventricular fibrillation, and ventricular tachycardia) with or without an electric mattress. The sensitivity, specificity, positive predictable value, negative predictable value, and accuracy of AEDs were calculated to differentiate shockable from nonshockable rhythms. Times required to interpret the ECGs were checked with and without an electric mattress. RESULTS: A total of 320 tests were recorded, and each AED was tested a total of 80 times. Depending on the AED model used on an electric mattress, sensitivity ranged from 55% to 90% with a specificity of 100%, and accuracy ranged from 77.5% to 95%. For some AEDs, sensitivity was reduced compared to the control. Although there was no significant difference in times required to interpret ECG signals with or without an electric mattress, some AEDs detected a relatively small interference as motion artifacts when an electric mattress was used. All recorded ECG rhythms on an electric mattress showed baseline artifacts and these artifacts lessened with increasing distance from an electric mattress. CONCLUSION: This study suggests that an electric mattress could affect the shockable rhythm performance of some AEDs. Electromagnetic interference generated by an electric mattress could interfere with the ability of some commercial AEDs to correctly interpret stimulated ECG rhythms and provide appropriate defibrillation.
Subject(s)
Artifacts , Defibrillators , Electrocardiography , Heart Arrest , Magnetic Fields , Magnets , Sensitivity and Specificity , Ventricular Fibrillation , VibrationABSTRACT
Objective To explore the impacts of magnetic fields of different intensities on the superoxide dismutase (SOD) activity and malondialdchvde (MDA) levels in rat pancreatic islet cells under normal and hypoxic conditions.Methods Rat pancreatic islet cells were culured,and after 3 days were subjected to a magnetic field of either 44.8 mT,90.6 mT or 182.1 mT under either normal or hypoxic conditions.Control cells received no magnetic field exposure,SOD activity and MDA level were measured after 72 hr.Results The cultured cells grew linearly with optical density (OD) of 0.067 ± 0.021 after 2 days and 0.449 ± 0.113 afier 5 days.SOD activity was significantly lower in the three magnetic field intervention groups than in the control group.Under hypoxic culture conditions,in all the magnetic field intervention groups SOD activity increased at first and then deereased.Under normal culture conditions,MDA content was significantly higher in the 182.1 mT group than in the control group.In the other two groups it was significantly lower.Conclusion Magnetic field exposure can cause oxidative damage to pancreatic islet cells,at least rat cells in culture.Under hypoxic culture conditions a magnetic field can inhibit such damage.
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Objective To observe the effects of permanent magnetic fields with different magnetic inductions on oxidative damage to human brain microvascular endothelial cells (HBMECs) under normal and hypoxic conditions. Methods HBMECs were cultured in vitro under normal and hypoxic conditions,then divided into a control group and groups receiving magnetic induction at 8.1,16.5,20.3,26.0,27.3,62.5,110.7 and 215.6 mT.Changes in superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in each group were measured 72 h after exposure to the magnetic fields. Results Under normal conditions the SOD activities of the magnetic groups were not significantly different from that of the control group. Only the MDA content of the 215.6 mT group was statistically different (slightly higher) than that of the control group (P ＜ 0.05 ).Under hypoxic conditions,there was again no statistically significant difference in SOD activity,but the MDA content of the 110.7 mT group was significantly lower. Conclusions Under normal conditions,a 215.6 mT permanent magnetic field has an effect on MDA in HBMECs; under hypoxic conditions a 110.7 mT permanent magnetic field has such an effect.
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Objective To observe the effect of a rotating magnetic field in preventing and treating irradiation-induced esophagitis in rats. Methods Forty female Wistar rats were randomized into 5 groups:a non-irradiated control group,an irradiation group,an amifostine treatment group ( amifostine group ),a 90 min magnetic field treatment group (90 min magnetic group) and a 120 min magnetic field treatment group ( 120 min magnetic group),with 8 rats in each group.The esophaguses of all rats except those in the control group were exposed to a single irradiation with 6 MV X-rays from a linear accelerator at a dosage of 43 Gy.Four rats in each group were randomly chosen to be observed 1 and 2 weeks after the irradiation.Blood cytokines were detected in their arterial blood.Any pathological changes of the esophagus were observed with HE staining under a light microscope at the same time. Results Irradiation-induced esophagitis was observed in the irradiation group 7 days after irradiation,with obvious exfoliation and necrosis of the esophagal epithelium mucosae.The submucosa were hyperaemic and dropsical with abundant inflammatory cell infiltration.The pathological changes of the esophagus were similar at 7 and 14 days after irradiation.However,the irradiation-induced esophagitis of rats in the amifostine group,the 90 min magnetic group and the 120 min magnetic group were relatively slighter and the blood leucocytes and neutrophis in those 3 groups were significantly lower than those in the irradiation group,while a tendency toward repair of the mucosa of the esophagus was detected.Serum TNF-α,IL-1 and IL-6 in the 90 min magnetic group and 120 min magnetic group were significantly lower than those in the irradiation group. Conclusions Both a rotating magnetic field and amifostine can help prevent and treat irradiation-induced esophagitis.Their therapeutic efficacy is similar.Exposure to a rotating magnetic field could inhibit the expression of inflammatory factors,and thus lessen the inflammatory reaction of acute irradiation-induced esophagitis.
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Objective To observe the effects of a natural static magnetic field (NSMF) on the proliferation of human hepatocarcinoma cells. Methods Three human hepatocarcinoma cell lines ( BEL-7402,HEP G-2 and QGY-7701 ) were cultured under standard conditions and then exposed to NSMFs of 0.1 Tesla at 600 Hz,0.2 Tesla at 250 Hz,0.2 Tesla at 400 Hz or 0.2 Tesla at 500 Hz for 30 minutes daily for 3 or 6 days.Flow cytometry and the XTT cell proliferation assay were used to check apoptosis and the proliferation of cells all groups. Results Only exposure to 0.2 Tesla magnetism at 400 Hz induced apoptosis of the BEL-7402 cell line.None of the NSMFs induced apoptosis in the other 2 hepatocarcinoma cell lines. Conclusions Different reactions of the three hepatocarcinoma cell lines to the same NSMF implies that each cell line has its own features,and that individualized NSMF treatment protocols should be adopted for better clinical outcomes.
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Objective To evaluate the effects of static magnetic fields (SMFs) of different intensity and exposure duration on the proliferation and apoptosis of human umbilical cord endothelial cells (HUVECs),and their release of nitric oxide (NO),6-keto-prostacyclin 1α (6-keto-PGF1α) and endothelin (ET-1).Methods Cultured HUVECs were exposed to a SMF at 5,22,86 or 135 mT for 8,12 or 24 hours.Their proliferation and apoptosis were monitored by flow cytometry (FCM).The medium was collected to test its NO content by optical density.ET-1 and 6-keto-PGF1α were measured by radioimmunization.Results ( 1 ) The proliferation of HUVECs increased when the cells were exposed to a SMF at 5 mT for 8 h,but a SMF at 135 mT for 12 h or 24 h inhibited the proliferation of HUVECs.(2)An SMF had no effect on apoptosis of HUVECs.(3)An SMF at 5 mT for 8 h increased the release of NO and 6-keto-PGF1 a,but the release of NO and 6-keto-PGF1 a decreased when the SMF intensity was 135 mT or the cells were exposed to an SMF for 12 h or 24 h.(4) An SMF at 5 mT or 22 mT for 8 h did not effect the release of ET-1.An SMF at 86 mT or 135 mT increased the release of ET-1.Compared with a control group,an SMF at 5 mT for 12 or 24 h did not affect the release of ET1,but at 22,80 or 135 mT,the release of ET-1 decreased significantly.Conclusions Exposure to a low intensity SMF for a short duration could improve the proliferation of HUVECs and increase the release of vasoactive factors,but if HUVECs are exposed to a strong SMF or exposed for a long duration,the proliferation and the release of vasoactive factors is decreased.
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Objective To estimate any influence of strong pulsed magnetic fields on the expression of growth-related genes in human bladder cancer BIU-87 cells. Methods Human BIU-87 cells were cultured in vitro and randomly divided into a magnetic field group and a control group. Each group was further divided into 24 h, 48 h and 72 h sub-groups. The magnetic field group cells were exposed to an 8 T magnetic field pulsed at 15 Hz for 2 h every day. The control group cells also placed on the same environment, but not exposed to any strong, pulsed magnetic field. The expression of B cell lymphoma/leukemia gene-2 (Bcl-2) mRNA, Bax mRNA and caspase-3 mRNA was measured with RT-PCR, and flow cytometry was used to evaluate the expression of the Bcl-2, Bax and caspase-3 genes of the tumor cells in vitro. Results The expression of Bax mRNA and protein was significantly higher in the cells exposed to the magnetic field than in the control groups. The expression of Bcl-2 mRNA and protein was significantly less. The expression of caspase-3 mRNA and protein in the two groups showed no significant differences.Conclusions A strong, pulsed magnetic field can inhibit the growth of bladder tumor BIU-87 cells and promote their apoptosis. The mechanism is probably related with the magnetic field promoting Bax mRNA and protein expression and inhibiting Bcl-2 mRNA and protein expression.