جستجوی مقالات مرتبط با کلیدواژه « Electromagnetic Fields » در نشریات گروه « پزشکی »

 Non-ionizing electromagnetic field (EMF) exposure therapies are non-invasive and safe treatment options that can potentially change available treatments. In this review, we examined the applications of such therapies in dental implant surgery by conducting a systematic review.

A comprehensive search of several international electronic databases was conducted from inception to December 14, 2022. This review included interventional studies that evaluated the advantages of adjunctive magnetic or combined EMFs on dental implants compared to conventional treatments.

 From a total of 1695 studies, 12 preclinical and clinical studies were selected, discussing EMF-based treatments for enhancing implant stability, osteogenesis, and osseointegration, as well as alleviating post-implant surgery manifestations. Almost all studies on maxillary and mandibular implant stability showed beneficial effects of non-ionizing EMF in humans. Most studies evaluating osteogenesis and osseointegration indicated that EMF exposure could accelerate bone repair and peri-implant bone formation and increase bone contact ratios, bone volume fraction (bone volume/total volume), trabecular number, and trabecular thickness. Only two clinical studies examined the effect of EMF on pain and swelling after dental implant surgery, with one finding that subjects exposed to EMF used analgesics fewer times and in far lower doses than the control group and the other finding no significant difference in reducing these outcomes between the groups.

 Overall, devices that deliver non-ionizing low-level EMF can be a viable and widely recognized non-invasive adjuvant therapy for attaining success and better outcomes after dental implant surgery due to their efficacy, safety, and short exposure time.

Electromagnetic induction hyperthermia is a promising method to treat the deep-seated tumors such as brain and prostatic tumors. This technique is performed using the induction of electromagnetic waves in the ferromagnetic cores implanted at the solid tumor. This study aims at determining the conditions of the optimal thermal distribution in the different frequencies before performing the in vitro cellular study. In this experimental study, the i-Cu alloy (70.4-29.6; wt%) was prepared and characterized and then the parameters, affecting the amount of induction heating in the ferromagnetic core, were investigated. Self-regulating cores in 1, 3, 6, and 9 arrangements in the water phantom with a volume of 2 cm3 were used as a replacement for solid tumor. Inductively Coupled Plasma (ICP) analysis and Energy Dispersive X-ray Spectroscopy (EDS) show the uniformity of the alloy after 4 times remeling by vacuum arc remelting furnace. The Vibrating Sample Magnetometer (VSM) shows that the Curie temperature (TC) of the ferromagnetic core is less than 50 °C. Temperature profile with a frequency of 100-400 kHz for 30 min, was extracted by infrared imaging camera, indicating the increase temperature in the range of 42 °C to 46 °C.  The optimum conditions with used hyperthermia system are supplied in the frequency of 100 kHz, 200 kHz and 400 kHz with 6, 3 and 1 seeds, respectively. It is also possible to induce a temperature up to 50 °C by increasing the number of seeds at a constant frequency and power, or by increasing the applied frequency at a constant number of seeds.

Previous research has shown that children are more vulnerable to the adverse effects of radiofrequency electromagnetic fields (RF-EMFs) and blue light emitted from digital screens compared to healthy adults. This paper presents the findings of a cross-sectional study conducted in Yasuj, Iran, to investigate the screen time habits of children and adolescents and its potential impact on their health. A total of 63 participants, including 44 boys and 19 girls, were randomly selected for the study. The results showed that the average daily screen time for the children was 87.38 minutes, with a standard deviation of 49.58. When examining the specific purposes of screen time, it was found that the children spent an average of 17.54 minutes per day on screens for school assignments, 70 minutes per day for recreational purposes, and 23.41 minutes per day for contacting family, friends, and relatives. Our study highlights that a significant portion of the children’s screen time was allocated to recreational activities. We observed some differences in screen time between girls and boys. Boys had a slightly higher overall daily screen time, primarily driven by more recreational screen time. However, girls spent slightly more time on screens for school assignments. The screen time for social interactions was similar for both genders. Our findings on the cognitive performance of children with different levels of screen time will be published in a separate paper.

Exposure to low-frequency electromagnetic fields (LF-EMF) has been considered a global concern because of its harmful effects on human health (cancer, neurodegenerative disorders, etc.). According to the International Agency for Research on Cancer, EMF has been classified as a possible cancerous element for human health. Antioxidants such as vitamin C improve the damage caused by EMF by reducing oxidative stress. To evaluate the effects of EMF on the serum total protein, blood sugar, albumin and triglyceride, and the inhibitory role of vitamin C, 40 male BALB/c mice were recruited. Participants were randomly distributed into four groups 1- exposure to LF-EMF, 2- exposure to LF-EMF which received vitamin C (50 mg/kg), 3- exposure to LF-EMF which received vitamin C (100 mg/kg), and 4- control group (no exposure). The experimental groups (1-3) received LF-EMF (50 Hz, 4 mT, 4 hours/day, and 1 month) while both groups 2 and 3 had intraperitoneally injected vitamin C (50 mg/kg, 100 mg/kg) every other day basis respectively. The obtained results demonstrated higher triglyceride and total protein levels and lower albumin and blood sugar levels in the LF-EMF group compared to controls while vitamin C restricts their alterations (p<0.05). To sum it up, our data show that intraperitoneal injection of vitamin C restricts the effects of LF-EMF exposure on the biochemical parameters in mice. However, the antioxidant characteristics of vitamin C may be probably involved in the LF-EMF effects of biochemical parameters in mice.

This study aimed to assess the specific absorption rate (SAR) due to the exposure to the radiations from different brands of cellphones, and to compare it with guideline values. The SAR is calculated using the mathematic equation based on the measured energy.

In this regard, 204 cellphones from different brands were randomly surveyed. A questionnaire composed of demographic and self-reported questions was designed to survey the students’ awareness and attitude about cellphone brands, usage duration and observed health effects. The Kolmogorov-Smirnov test was used for statistical analysis at frequencies of 900 and 1800 MHz and the differences between brands were assessed by the Kruskal-Wallis test.

According to the results, it was found that 46.7% and 8.4% of people used cellphones for less than 4 and more than 12 hours per day, respectively. According to the statistical tests, students with higher talk time, sent messages, and Internet usage, and those using wireless hands-free, had the most reported symptoms of headache, tinnitus, eye burning and eyestrain, sleep disturbances, and skin color changes.

The authors found that there was no significant difference between different brands based on the SAR values. However, Samsung and Nokia brands had the highest SAR values and ASUS brand had the lowest ones. Also, the type of game apps (online/offline) was significantly correlated with possible health effects. Therefore, regarding these cases, as well as the fact that many dangers of cellphone use are unknown, it is recommended to use cellphones cautiously.

During the last decade, people have been dramatically exposed to radiation emitted from widely-used radiofrequency electromagnetic fields (RF-EMF) generating devices.  This study aimed to evaluate the effects of exposure to RF-EMF emitted from smart phones and Wi-Fi routers on the growth rate and antibiotic sensitivity of Enterococcus faecalis (E. faecalis) as a pathogen in the root canals of teeth. In this experimental study, E. faecalis ATCC 19115 was used, characterized and confirmed by morphological and biochemical tests. Antibiotic susceptibility test was measured for several common antibiotics. To perform antibiotic susceptibility tests, disk diffusion (Kirby-Bauer) method on Mueller-Hinton agar plates was used before and after exposure to RF-EMFs emitted from a commercial Wi-Fi router or a mobile phone simulator. Moreover, we measured the optical density at 625 nm after different exposure times using a calibrated UV-visible spectrophotometer to evaluate the effect of RF-EMF exposure on the bacterial growth rate.  Exposure to RF-EMF significantly altered the antimicrobial sensitivity of the E. faecalis. While, the susceptibility of the bacteria decreased significantly after 6 h of exposure, longer exposure time (e.g. exposure for 24 h) increased the susceptibility of the bacteria to all antibiotics. Furthermore, it was found that the bacteria tended to regress to their early state. Moreover, the non-exposed E. faecalis showed a slower growth rate than the bacteria exposed to RF-EMFs.   Exposure to RF-EMF emitted by Wi-Fi routers or mobile phone simulator can significantly change the antibiotic susceptibility and growth rate of E. faecalis.

Exposure to the low frequency electric and magnetic fields (ELF-EMF) is very common in workers occupied in the combined cycle power plant during work shifts  The present study aimed to measure ELF-EMF flux density among shift and non-shift workers, determine job stress among workers and office workers, and identify major factors associated with job stress in the studied groups.

In this cross-sectional study, the exposed group was divided into 75 shift workers and 75 non-shift workers. Seventy-five office workers were selected as the reference group. The participants’ exposure to ELF-EMF was measured by the EMF-828 device. In addition, Osipow Occupational Stress Questionnaire was used to assess the participants’ stress levels.

Maximum levels of ELF-EMF among shift workers, non-shift workers, and office workers were 28.67 μT, 23.43 μT, and 0.06 μT, respectively.  Although the explosion rate to ELF-EMF was higher in the shift and non-shift workers than the office one's, this rate in both of them were lower than the recommended limit as suggested by the American Conference of Governmental Industrial Hygienists (ACGIH). The highest stress score was related to shift workers exposed to ELF-EMF, in which 42.7% of them experienced moderate to high levels of job stress. Multivariate linear regression analysis showed a significant association between shift work and exposure to ELF-EMF with increased stress.

The findings suggested that exposure to ELF-EMF, even at low intensities, is associated with increased stress. Moreover, Shift work is another risk factor for stress.

Gastric cancer is one of the most prevalent and deadliest cancers in the world. Environmental factors including chemicals, sunlight, and electromagnetic fields can induce changes in gene expression. Though the resizing mechanism of its effect has not been fully recognized, free radicals are seen as the possible mechanism involved. Although low-frequency electromagnetic fields are not considered a carcinogenic factor, some studies have shown disruption in deoxyribonucleic acid (DNA) and gene expression in different cell categories.

This study was intendant to examine the effects of low-frequency electromagnetic flux densities of 0.2 and 2 mT on the expression of cathepsin L2 (CTSL2) and suppressor of cytokine signaling 3 (SOCS3) genes in adenocarcinoma gastric (AGS) cell lines.

The AGS cell line was cultured in Hamas12 and was exposed to electromagnetic fields continuously and discontinuously for 18 hours. Moreover, Cell viability was assessed by the MTT (3-(4, 5-Dimethylthiazol-2-yl)) assay. The change in the expression of genes was measured by real-time polymerase chain reaction (PCR).

Low-frequency electromagnetic fields increased gene expression compared to the control group. The changes in the expression are directly associated with the electromagnetic field strength. Expression levels of CTSL2 were increased under the exposure of electromagnetic fields and this increase was significant when discontinuous exposure was applied (33.26 ± 7.4 fold change for 0.2mT and 64.4±7.7 for 2mT, p- value <0.001). SOCS3 was significantly up-regulated under the exposure of discontinuous magnetic flux density of 2mT (p-value <0.05).

In general, all experimental groups under the illuminated fields have increased in expression. This is directly associated with the field-strength increase, with more pronounced changes in expression in the group subjected to intermittent radiation.

Breast cancer is the most common metastatic malignancy and the second leading cause of cancer death in women. Recently, extremely low-frequency electromagnetic fields (ELF-EMFs) seem to modulate the rate of proliferation and enhance apoptosis and are considered as an emerging approach to cancer therapy. Despite recent success in the electromagnetic fields, the results are still neither definitive nor even contradictory.

In this study, induction of apoptosis was considered as one of the possible mechanisms of ELF-EMFs on cancer inhibition. Breast cancer cell lines were exposed to a 1 Hz, 100 mT ELF-EMF (2 h/day) for five days. The apoptosis rate of both the exposure and sham exposure groups was determined by flow cytometry. The expression levels of Bax and Bcl-2 were evaluated by real-time PCR.

The mRNA expression levels of Bax were increased; while the expression of Bcl-2 showed a decrease in MDA-MB231 cells exposed to 1Hz EMF compared with sham exposure. Moreover, the ratio of Bax/Bcl-2 was significantly increased in comparison to the sham exposure. The increased Bax/Bcl-2 ratio induces cell apoptosis.

It is suggested that ELF-EMF is a new adjuvant therapeutical method that may contribute to anti-cancer and cancer therapy research.

Recently, increasing use of electronic devices, which generate electromagnetic fields, focused researchers' attention on investigating the effects of electromagnetic fields on human health. The aim of this study was to investigate the effects of extremely low frequency electromagnetic fields on, weight of spleen and weight of liver and kidney and role of Vitamin C in the mice.In this experimental study, 24 adult male mice (Balb/C) were divided into 3 groups. The control group consist of 8 mice were kept in normal conditions. The group exposure to electromagnetic field consist of 8 mice, which were exposed to electromagnetic low field (ELF) (50Hz, 4Mt) for 15 days, and the group that exposure to electromagnetic field supplemented with vitamin C, contains 8 mice that were exposed to ELF (50Hz, 4Mt) for 15 days and vitamin C were injected intraperitoneally 7 times. After 15 days, the weight of mice were measured, then this samples were dissected, finally spleen, liver and kidney was removed to measure. Data was analyzed using one way ANOVA test. The results show electromagnetic fields leads a significant reduction in weight of spleen and weight of liver and appropriate dose of vitamin C is a treatment that damage is caused by electromagnetic fields with a frequency of 50 Hz decreases.

Complex regional pain syndrome (CRPS) is a frequent and devastating complication that occurs after trauma and immobilization and is very frequent after wrist fractures (1% - 37%) and after volar locking plate fixation (3% - 10%). The development of CRPS considerably lengthens the time of recovery after a traumatic injury, causing a great impact on work, social activities and psychological well-being.

To demonstrate the efficacy of physical therapy and TIOBEC® (a combination of α-lipoic acid and vitamin B, C, and E) in terms of pain amelioration and edema reduction in the management of CRPS in a small series of patients.

Prospective before-and-after study. The protocol of treatment included physical therapy (electromagnetic fields applied to the symptomatic limb [20 Hz-50 Gauss-20 min] followed by manual therapy [assisted, active and resisted mobilization plus manual drainage]) plus oral medication (TIOBEC® 400 mg) prescribed twice a day. Components of TIOBEC® included α-lipoic acid (800 mg), vitamin C (60 mg), niacin (36 mg), vitamin E (10 mg), vitamin B1 (25 mg), vitamin B2 (25 mg), vitamin B6 (9.5 mg), vitamin B12 (25 µg) and folic acid (400 µg). Outcome measures included VAS (visual analog scale) pain scale, reduction of edema at the metacarpal phalangeal joint (hand/foot) and functional evaluation (by Kapandji score) before-and-after treatment. Outcome measures were evaluated at baseline and at mid-term (4 months follow-up period).

Five patients (mean [SD] age: 61 [7.9]) who had been diagnosed clinically by neurophysiological sympathetic skin-response, gammagraphy, and radiography were recruited in the study. Mean electrotherapy and manual therapy sessions were 40 ± 27.83. Mean oral medication (TIOBEC®) was 84 ± 13.41 days. Physical therapy and TIOBEC® decreased pain from 6.6 ± 0.54 to 2.8 ± 1.3 (P = 0.001), decreased edema from 12 ± 5.7 mm to 4 ± 4.18 mm (P = 0.035) and improved functional Kapandji score from 6.2 ± 2.77 to 9.4 ± 1.34 (P = 0.029). Neither of the patients stopped oral medication nor reported adverse events.

The protocol that includes the electromagnetic field, manual therapy, and TIOBEC® may be safely used in patients with CRPS in an attempt to ameliorate pain, to reduce edema and to improve function. In light of the results of this study, the protocol used might accelerate recovery time. More studies are needed to corroborate the present results observed in this pilot study.

Breast cancer is the most common cause of cancer-related death among women. Recently, extremely low-frequency electromagnetic field (ELF-EMF) has been proposed as a new interfering agent with future therapeutic potentials. Many studies have revealed that cellular processes such as apoptosis in breast cancer are affected by ELF-EMFs. However, more researches are needed to clarify the underlying mechanism of action for these fields. In this study, the apoptotic effect of ELF-EMF on the MC4L2 cell line was examined and the mRNA expression level of the P21 and P38 genes were further investigated.

A triple-positive mouse breast cancer cell line (MC4L2) was purchased from the Genetic Resource Center (Iran). This study was performed on two groups of ELF-EMF exposure (100mT/1 Hz for 5 days, 120 min each day) and sham exposure. Cell viability and apoptosis rate of both the exposure and sham exposure groups weredetermined by flow cytometry. Alterations in the P21 and P38 mRNAs expression levelswere investigated; using real-time PCR.

ELF-EMF exposure induced 30% apoptosis in MC4L2 cells compared with the control group. The mRNA expression level of P38 and P21 was significantly increased after ELF-EMF exposure compared to the control group.

ELF-EMF induces apoptosis in the MC4L2 triple-positive cell line. Furthermore, this exposure affects important gene expression involved in the cell cycle. Our data propose that ELF-EMF in a specific time, intensity and frequency could be beneficial for breast cancer treatment. However, more studies are required to confirm our findings.

Pulsed radiofrequency (PRF) affects animal and plant tissues; however, the mechanism has not been defined. We hypothesized that the magnetic field produced by PRF exerts its effects by the magnetic sensitivity of transitions between spin states -a spin-correlated radical-pair mechanism (SCRPM)- which, in turn, affects the rates of chemical reactions with participation of paramagnetic species.

This study aimed to evaluate the effects of PRF on redox equilibrium and inflammatory status in a standard model of muscle injury in rats.

Twenty-four animals were subjected to a single impact trauma to the left quadriceps and the groups exposed and not exposed to PRF were compared. On day 7 of the experiment, the animals were killed and the quadriceps muscles were removed for analysis.

There was a significant increase in the concentration of thiobarbituric acid reactive substances (TBARS) in the muscle of animals from the trauma group (+233%), and this increase was eliminated by PRF administration. Superoxide dismutase (SOD) activity was increased (+411%) by trauma, resulting in significantly higher consumption of catalase (-72%), while PRF administration brought both of these markers back to levels close to those of the control group. Trauma induced considerable production of interleukins TNF-α, IL-1β, and IL-6 (+215%, +262%, and +326% vs. controls, respectively) and these effects were also significantly reduced by PRF administration.

In total, PRF inhibits oxidative stress and restores antioxidant enzymes to control levels and may block production of inflammatory markers in muscles of animals subjected to trauma. By modulating redox equilibrium, PRF treatment might block production of noxious mediators involved in development of trauma-induced injury.

Extremely low-frequency electromagnetic fields (ELF-EMFs) are abundantly produced in modern societies. In recent years, interest in the possible effects of ELF-EMFs on the immune system has progressively increased.

To examine the effects of ELF-EMFs with magnetic flux densities of 1, 100, 500, and 2000 µT on the serum levels of interleukin (IL)-9, IL-10, and tumor necrosis factor-alpha (TNF-α).

80 adult male rats were exposed to ELF-EMFs at a frequency of 50 Hz for 2 h/day for 60 days. The serum cytokines were measured at two phases of pre- and post-stimulation of the immune system by human serum albumin (HSA).

Serum levels of IL-9 and TNF-α, as pro-inflammatory cytokines, were decreased due to 50 Hz EMFs exposure compared with the controls in the pre- and post-stimulation phases. On the contrary, exposures to 1 and 100 µT 50 Hz EMFs increased the levels of antiinflammatory cytokine, and IL-10 only in the pre-stimulation phase. In the post-stimulation phase, the mean level of serum IL-10 was not changed in the experimental groups.

The magnetic flux densities of 1 and 100 µT 50 Hz EMFs had more immunological effects than EMFs with higher densities. Exposure to 50 Hz EMFs may activate anti-inflammatory effects in rats, by down-modulation of pro-inflammatory cytokines (IL-9 and TNF-α) and induction of the anti-inflammatory cytokine (IL-10).

A slight increase in the childhood cancer trend has been observed for the past few decades. Non-ionizing radiation is one of the environmental factors linked to childhood cancers. This review is conducted to assess the association between non-ionizing radiation and childhood cancer based on all original studies to date.

A systematic search was conducted on the titles and abstracts pertaining to non-ionizing radiation and childhood cancers using the PubMed, Scopus, SAGE and ScienceDirect databases from inception up to November 2018. Quality of each article was appraised using the Newcastle-Ottawa Scale, meta-analysis was performed with Review Manager, and fixed effects were used to estimate the pooled OR of the selected studies.

A total of 15 articles met all the selection criteria. Twelve articles were included in the meta-analysis. Pooled risk estimates of the 12 studies, obtained via fixed effects model, showed that children exposed to 0.2 µT or more of EMF non-ionizing radiation run 1.33 times higher risks of contracting childhood cancer compared to those with less than 0.2 µT exposure (95% CI: 1.10, 1.60). The studies were statistically homogeneous (chi-squared P=0.71, I2=0%), and there was no evidence of publication bias.

It cannot be concluded that children exposed to non-ionizing radiation have higher risks of childhood cancer compared to those who were not exposed as claimed by the previous reviews. However, concerns about non-ionizing radiation exposure and childhood cancer should not be neglected.

Today the use of electromagnetic waves has dramatically increased in modern industrial societies. This study aimed to investigate the effect of prenatal exposure to 2.4 GHz wireless frequency on forelimb development in an NMRI mouse in vivo.

A total of 21 female mice weighing 25-30 g were included in the present study. They were randomly assigned to three groups, namely control (n=7), sham (n=7), and experimental (n=7). After mating, the experimental group was exposed to 2.4 GHz radio frequency at a distance of 20-30 cm from the device, 4 h per day until the delivery. The sham group was placed at a distance of 20-30 cm from the device every day without exposure to electromagnetic waves, and the control group had a pregnancy period without any stress and electromagnetic wave exposure. After giving birth, the forelimbs were isolated from the infants and examined by stereological studies and RT-PCR for the evaluation of osteocalcin and RUNX2 gene expression.

Although, at first glance, there was no macroscopic teratogen effect in forelimbs in all groups, via a stereological method, we showed that bone and cartilage volume decreased in the experimental group compared to the other groups. We also found that the experimental group had lower expression of the osteocalcin and RUNX2 gene than the control and sham groups did. However, there were no significant differences between the control and sham groups in terms of bone and cartilage volume and gene expression.

Although teratogen effect of prenatal exposure to 2.4 GHz radio frequency on forelimbs was not demonstrated macroscopically, further studies showed negative effects on the forelimb bone, cartilage volume, and gene expression.

This study aimed to determine whether exposure to pulsed electromagnetic field (PEMF) can impair behavioral failure as induced by PTSD, and also its possible effects on hippocampal neurogenesis. PEMF was used as a non-invasive therapeutic tool in psychiatry. Male rats were divided into Control-Sham exposed, Control-PEMF, PTSD-Sham exposed, and PTSD-PEMF groups. PTSD rats were conducted by the single prolonged stress procedures and then conditioned by the contextual fear conditioning apparatus. Control rats were only conditioned. Experimental rats were submitted to daily PEMF (7 mT, 30 Hz for 16 min/day, 14 days). Sham-exposed groups were submitted to the turned off PEMF apparatus. Fear extinction, sensitized fear and anxiety, cell density in the hippocampus, and proliferation and survival rate of BrdU-labeled cells were evaluated. Freezing of PTSD-PEMF rats was significantly lower than PTSD-Sham exposed. In the PTSD-PEMF, center and total crossing in open field, also the percentage of open arms entry and time in the elevated plus maze, significantly increased as compared with PTSD-Sham exposed (P<0.001). Numbers of CA1, CA3, and DG cells in PTSD-PEMF and Control-Sham exposed groups were significantly more than PTSD-Sham exposed (P<0.001). There were more BrdU-positive cells in the DG of the PTSD-PEMF as compared with the PTSD-Sham exposed. Qualitative observations showed an increased number of surviving BrdU-positive cells in the PTSD-PEMF as compared with PTSD-Sham exposed. Using 14-day PEM attenuates the PTSD-induced failure of conditioned fear extinction and exaggerated sensitized fear, and this might be related to the neuroprotective effects of magnetic fields on the hippocampus.