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Considering enormous growth in population, technical advancement, and added reliance on electronic devices leading to adverse health effects, in situ simulations were made to evaluate effects of non-ionizing radiations emitted from three cell phone towers (T1, T2, and T3) of frequency bands (800, 1800, 2300 MHz), (900, 1800, 2300 MHz), and (1800 MHz), respectively. Five sites (S1-S5) were selected near cell phone towers exhibiting different power densities. The site with zero power density was considered as control. Effects of radiations were studied on morphology; protein content; antioxidant enzymes like ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione-S-transferase (GST), guaiacol peroxidase (POD), and glutathione reductase (GR); and genotoxicity using Allium cepa. Mean power density (µW/cm2) was recorded as 1.05, 1.18, 1.6, 2.73, and 12.9 for sites 1, 2, 3, 4, and 5, respectively. A significant change in morphology, root length, fresh weight, and dry weight in Allium cepa was observed under the exposure at different sites. Protein content of roots showed significant difference for samples at all sites while bulbs at sites S4 and S5 when compared to control. Antioxidant activity for root in terms of APX, GST, and POD showed significant changes at S4 and S5 and GR at site S5 and SOD at S1, S2, S3, S4, and S5. Similarly, bulbs showed significant changes at sites S4 and S5 for APX while at sites S3, S4, and S5 for POD and S2, S3, S4, and S5 for SOD and S5 for GR and GST. Genotoxicity study has shown induction of abnormalities at different stages of the cell cycle in Allium cepa root tips. The samples under exposure to radiation with maximum power density have shown maximum induction of oxidative stress and genotoxicity.
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Telefone Celular , Cebolas , Monitoramento Ambiental , Glutationa Redutase , Antioxidantes , Glutationa Transferase , Superóxido Dismutase , Radiação não IonizanteRESUMO
With increasing technological developments, exposure to non-ionizing radiations has become unavoidable as people cannot escape from electromagnetic field sources, such as Wi-Fi, electric wires, microwave oven, radio, telecommunication, bluetooth devices, etc. These radiations can be associated with increased health problems of the users. This review aims to determine the effects of non-ionizing electromagnetic radiations on female fertility. To date, several in vitro and in vivo studies unveiled that exposure to non-ionizing radiations brings about harmful effects on oocytes, ovarian follicles, endometrial tissue, estrous cycle, reproductive endocrine hormones, developing embryo, and fetal development in animal models. Non-ionizing radiation also upsurges the free radical load in the uterus and ovary, which leads to inhibition of cell growth and DNA disruptions. In conclusion, non-ionizing electromagnetic radiations can cause alterations in both germ cells as well as in their nourishing environment and also affect other female reproductive parameters that might lead to infertility.
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Campos Eletromagnéticos , Reprodução , Animais , Feminino , Campos Eletromagnéticos/efeitos adversos , Radiação Eletromagnética , FertilidadeRESUMO
Unprecedented growth in the communication sector and expanded usage of the number of wireless devices in the past few decades have resulted in a tremendous increase in emissions of non-ionizing electromagnetic radiations (EMRs) in the environment. The widespread EMRs have induced many significant changes in biological systems leading to oxidative stress as well as DNA damage. Considering this, the present study was planned to study the effects of EMRs at 900 MHz frequency with the power density of 10.0 dBm (0.01 W) at variable exposure periods (0.5 h, 1 h, 2 h, 4 h, and 8 h per day for 7 days) on percentage germination, morphological characteristics, protein content, lipid peroxidation in terms of malondialdehyde content (MDA), and antioxidant defense system of Trigonella foenum-graecum test system. The genotoxicity was also evaluated using similar conditions. It was observed that EMRs significantly decreased the germination percentage at an exposure time of 4 h and 8 h. Fresh weight and dry weight of root and shoot did not show significant variations, while the root and shoot length have shown significant variations for 4 h and 8 h exposure period. Further, EMRs enhanced MDA indicating lipid peroxidation. In response to exposure of EMRs, there was a significant up-regulation in the activities of enzymes such as ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione-S-transferase (GST), guaiacol peroxidase (POD), and glutathione reductase (GR) in the roots and shoots of Trigonella-foenum graecum. The genotoxicity study showed the induction of chromosomal aberrations in root tip cells of the Trigonella foenum-graecum test system. The present study revealed the induction of oxidative stress and genotoxicity of EMRs exposure in the test system.
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Trigonella , Trigonella/metabolismo , Estresse Oxidativo , Antioxidantes/metabolismo , Extratos Vegetais/farmacologia , Dano ao DNA , Fenômenos EletromagnéticosRESUMO
INTRODUCTION: Nowadays, using electromagnetic devices (EMD) has been increased. However, the control of EMD hazards was poorly evaluated, especially those affected the hippocampus. Regular physical exercises are safe, easily, inexpensive, and acceptable for long-term use. It is reported that exercise protects against many health problems. AIM: is to investigate the hypothesis of the possible prophylactic effect of exercise on the hippocampal damage induced by electromagnetic waves of Wi-Fi. MATERIAL AND METHODS: Adult male albino rats were divided into four groups: group I (control), group II (exercise), group III (Wi-Fi), and group IV (exercise -Wi-Fi). Hippocampi were subjected to biochemical, histological, and immunohistochemical techniques. RESULTS: In group III, a significant increase in the oxidative enzymes as well as decrease in antioxidant enzymes were detected in rat hippocampus. Additionally, the hippocampus showed degenerated pyramidal and granular neurons. An evident decrease in both PCNA and ZO-1 immunoreactivity was also noticed. In group IV, physical exercise alleviates the effect of Wi-Fi on previously mentioned parameters. CONCLUSION: Regular physical exercise performance significantly minimizes the hippocampal damage and protects against the hazarders of chronic Wi-Fi radiation exposure.
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Antioxidantes , Ondas de Rádio , Animais , Masculino , Antioxidantes/farmacologia , Hipocampo , RatosRESUMO
Present study exhibited the oxidative potential of microwave radiation (MWR) leading to the neurodegeneration in rats. Wistar rats were exposed at 2100 MHz frequency for 4 h/day, 5 days/week/3 months. Animals were exposed at an estimated specific absorption rate (0.453 W/kg) and power density (8.237 µW/m2). After exposure irradiated group was compared with control group. Results indicated that microwave exposure significantly increased the levels of serological triglycerides and cholesterol. Oxidative stress is observed through alteration of glutathione homeostasis followed by activated inflammatory response further confirmed by pro and anti-inflammatory cytokines in the exposed group. Histopathological assessments and electron microscopic observation confirmed a significant change in the myelination pattern and cellular organelles in the brain of exposed animals. Taking everything into account it can be concluded that chronic exposure of 2100-MHz frequency caused oxidative stress, which leads to neural damage and demyelination and may affect neural communication.
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Antioxidantes , Doenças Desmielinizantes , Animais , Antioxidantes/metabolismo , Encéfalo/metabolismo , Doenças Desmielinizantes/etiologia , Estresse Oxidativo , Ondas de Rádio , Ratos , Ratos WistarRESUMO
Behavioral impairments are the most pragmatic outcome of long-term mobile uses but the underlying causes are still poorly understood. Therefore, the Aim of the present study to determine the possible mechanism of mobile induced behavioral alterations by observing redox status, cholinesterase activity, cellular, genotoxic damage and cognitive alterations in rat hippocampus. This study was carried out on 24 male Wistar rats, randomly divided into four groups (n = 6 in each group): group I consisted of sham-exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation (900 MHz) at different time duration 1 h, 2 h, and 4 h respectively for 90 days. After 90 days of exposure, rats were assessing learning ability by using T-Maze. A significantly increased level of malondialdehyde (MDA) with concomitantly depleted levels of superoxide dismutase (SOD), catalase (CAT) and redox enzymes (GSH, GPX, GR, GST, G-6PDH) indicated an exposure of mobile emitted EMR induced oxidative stress by the depleted redox status of brain cells. The depletion in the acetylcholinesterase (AChE) level reveals altered neurotransmission in brain cells. Resultant cellular degeneration was also observed in the radiation-exposed hippocampus. Conclusively, the present study revealed that microwave radiation induces oxidative stress, depleted redox status, and causes DNA damage with the subsequent reduction in working memory in a time-dependent manner. This study provides insight over the associative reciprocity between redox status, cellular degeneration and reduced cholinergic activity, which presumably leads to the behavioral alterations following mobile emitted electromagnetic radiation.
Assuntos
Acetilcolinesterase/metabolismo , Encéfalo/efeitos da radiação , Radiação Eletromagnética , Memória de Curto Prazo/efeitos da radiação , Oxirredução , Estresse Oxidativo/efeitos da radiação , Animais , Encéfalo/metabolismo , Catalase/metabolismo , Dano ao DNA/efeitos da radiação , Glutationa Peroxidase/metabolismo , Masculino , Malondialdeído/metabolismo , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismo , Transmissão Sináptica/fisiologia , Transmissão Sináptica/efeitos da radiaçãoRESUMO
BACKGROUND: Our recent findings have demonstrated that electromagnetic radiations (EMR) (1.8 GHz radiofrequency) are able to in vitro induce morphometrical and morphological modifications of human leukocytes from normal donors. METHODS: In view of the evidence that polyphenols exert many beneficial effects on plants, animals and humans, leukocytes from human peripheral blood were pre-treated for 1 h with two polyphenol preparations from red grape before EMR exposure (1.8 GHz). RESULTS: Our data will show that polyphenol pre-treatment reverts to normality the morphology of irradiated leukocytes in comparison to irradiated cells only. Conversely, leukocyte morphometry seems to be not affected by this treatment. CONCLUSION: Here, we demonstrate that polyphenols are also able to normalize leukocyte morphology per se altered before as well as after irradiation. Finally, a working hypothesis aimed at clarifying the protective mechanisms exerted by polyphenols on irradiated leukocytes will be illustrated.
Assuntos
Forma Celular/efeitos da radiação , Citoproteção/efeitos dos fármacos , Radiação Eletromagnética , Leucócitos/citologia , Leucócitos/efeitos da radiação , Polifenóis/farmacologia , Lesões por Radiação/prevenção & controle , Adulto , Humanos , Contagem de Linfócitos , Doses de RadiaçãoRESUMO
NAD+-dependent Isocitrate Dehydrogenase (NAD+-IDH) could be one of the cell phone radiation targets. Enzyme activity alteration may lead to decline in sperm motility during radio-frequency electromagnetic waves (RF-EMW) exposure. The current case control study aimed to investigate the possible relationship between mitochondrial NAD+-IDH activity in human seminal plasma and sperm motility among asthenozoospermic cellular phone users. A total number of ninety idiopathic infertile males referred from the Department of Dermatology and Andrology, were enrolled in this study. NAD+-IDH activity was measured in human seminal plasma by spectrophotometer. Computer-aided sperm analysis (CASA) following WHO criteria has been used for semen analyses. The results showed that IDH activity was increased in patients with prolonged cell phone daily use ≥4 h/day. Its level, correlated negatively with either the motility ratio percentages (r = -0.46, p < 0.001) or the progressive motility percentages (r = -0.50, p < 0.001) in the study groups. The current study suggests that NAD+-IDH in human seminal plasma could be one of seminal plasma biomarkers reflecting the mitochondrial function of spermatozoa. Alteration of its level could reflect the defective motility of sperms among some cases of cellular phone users.
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OBJECTIVE: Cell phones use electromagnetic, nonionizing radiations in the microwave range, which some believe may be harmful to human health. The present study aimed to determine the effect of electromagnetic radiations (EMRs) on unstimulated/stimulated salivary flow rate and other health-related problems between the general populations residing in proximity to and far away from mobile phone base stations. MATERIALS AND METHODS: A total of four mobile base stations were randomly selected from four zones of Jaipur, Rajasthan, India. Twenty individuals who were residing in proximity to the selected mobile phone towers were taken as the case group and the other 20 individuals (control group) who were living nearly 1 km away in the periphery were selected for salivary analysis. Questions related to sleep disturbances were measured using Pittsburgh Sleep Quality Index (PSQI) and other health problems were included in the questionnaire. Chi-square test was used for statistical analysis. RESULTS: It was unveiled that a majority of the subjects who were residing near the mobile base station complained of sleep disturbances, headache, dizziness, irritability, concentration difficulties, and hypertension. A majority of the study subjects had significantly lesser stimulated salivary secretion (P < 0.01) as compared to the control subjects. CONCLUSIONS: The effects of prolonged exposure to EMRs from mobile phone base stations on the health and well-being of the general population cannot be ruled out. Further studies are warranted to evaluate the effect of electromagnetic fields (EMFs) on general health and more specifically on oral health.
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La proliferación incontrolada de estaciones base de telefonía móvil (EBTM) en centros urbanos y, especialmente, en zonas con establecimientos considerados como vulnerables a las radiaciones no ionizantes (RNI) con relación al tipo de personas que albergan, ha generado preocupación por los posibles efectos nocivos para la salud que se pueden presentar en la población, a causa de la exposición a las radiaciones electromagnéticas emitidas por este tipo de equipos. Para abordar esta situación desde un enfoque técnico-ambiental, se diseñó e implementó una metodología para diagnosticar áreas con alta exposición a RNI emitidas por EBTM, en la que se tienen en cuenta factores amenazantes y vulnerables de este potencial escenario de riesgo. Esta metodología se estructura mediante la elaboración de un inventario de EBTM, una zonificación de las áreas con alta exposición a RNI emitidas por estas fuentes radioeléctricas y la implementación de una matriz multicriterios. Con la interacción de estos tres elementos, se genera un mapa de riesgo por exposición a RNI emitidas por EBTM, que facilita a nivel territorial la localización y visualización de áreas con alta exposición, teniendo en cuenta las zonas con mayor grado de vulnerabilidad. Finalmente, con base en estos resultados se obtiene un diagnóstico del escenario de riesgo por el posicionamiento de EBTM, pudiéndose identificar las zonas críticas o de alto riesgo, las cuales son consideradas como áreas sensibles donde se deben realizar de forma prioritaria las mediciones de las RNI de inmisión y emisión y, determinar el cumpliendo de los límites establecidos. La validación de esta metodología se efectuó en el municipio de Cartago (Valle del Cauca), donde se diagnosticaron las áreas con alta exposición a las RNI emitidas por las EBTM y se determinaron las zonas de alto riesgo.
The uncontrolled proliferation of mobile phone base stations (MPBS) in urban centers and especially in areas with facilities considered vulnerable to non-ionizing radiation (NIR) in relation to the type of people they are home to has generated concerns about the potential adverse health effects that may occur in the population, because of the exposure to electromagnetic radiation emitted by this type of equipment. To address this situation from a technical and environmental approach, a methodology to diagnose areas exposed to NIR issued by MPBS was designed and implemented, which takes into account threatening and vulnerable factors of this potential risk scenario. This methodology is structured through the development of an MPBS inventory, a zoning of the areas exposed to high NIR emitted by these radio-electric sources, and the implementation of a multicriteria matrix. With the interaction of these three elements, a risk map is generated by exposure to NIR emitted by MPBS, which facilitates the location and visualization of areas with high exposure at the territorial level, thus considering the areas of greatest vulnerability. Finally, based on these results a diagnosis of the risk scenario is obtained by the MPBS positioning, being possible to identify critical or high risk areas, which are considered as sensitive areas where NIR emission and immision measurements must be done as a priority and determine the accomplishment of defined limits. The validation of this methodology was made in the municipality of Cartago (Valle del Cauca), where areas highly exposed to NIR emitted by EBTM were diagnosed and high-risk areas were identified.
Assuntos
Humanos , Radiação não Ionizante , Mapa de Risco , Telefone Celular , Radiação EletromagnéticaRESUMO
La omnipresencia de estaciones base de telefonía móvil (EBTM) en los territorios urbanos ha dado lugar a que la población esté siendo expuesta a las radiaciones no ionizantes (RNI) emitidas por este tipo de fuentes radioeléctricas, dado que estas han sido ubicadas cerca de los sitios donde habitan y/o concurren las personas que se han considerado más susceptibles a las radiaciones electromagnéticas. Este escenario se ha caracterizado por las constantes preocupaciones de los ciudadanos y expertos en torno a los posibles efectos nocivos que se pueden presentar por la exposición a las RNI; no obstante, existe también un ambiente de desconocimiento e incertidumbre frente al tema, lo que ha generado que sea más complejo evaluar este potencial riesgo de origen antrópico tecnológico. Por lo tanto, se consideró importante analizar la respuesta social frente al riesgo generado por las radiaciones electromagnéticas emitidas por EBTM, con el fin de realizar un diagnóstico integral de esta situación. Para ello, se adaptó el método del paradigma psicométrico, y se realizó un análisis descriptivo y multivariado, los cuales permitieron conocer la percepción social frente al riesgo en la zona que se consideró más crítica, según los resultados que surgieron del diagnóstico de las áreas urbanas expuestas a las RNI emitidas por las EBTM, localizadas en el municipio de Cartago (Valle del Cauca). Los resultados de los análisis muestran que la percepción de cada individuo se basa en juicios intuitivos y factores socioculturales, que se traducen en actitudes y decisiones que se toman frente al riesgo evaluado, que al parecer, en el imaginario social no ha sido concebido en su totalidad como un potencial factor de riesgo. Es por esto que se puede concluir que los juicios sobre el riesgo evaluado difieren no solo individualmente sino también colectivamente.
The omnipresence of mobile phone base stations (MPBS) in urban areas has resulted in the population being exposed to non-ionizing radiation (NIR) emitted by this type of radio sources, inasmuch as they have been located near places inhabited or frequently visited by people who are considered more susceptible to electromagnetic radiations. This scenario has been characterized by the constant concerns of citizens and experts about the possible adverse health effects that may occur from exposure to NIR. However, there is also an atmosphere of ignorance and uncertainty regarding the topic which makes it more difficult to evaluate this technological anthropogenic potential risk.. Therefore, it was considered important to analyze the social response in front of the risk generated by the electromagnetic radiation emitted by MPBS, in order to make an integral diagnosis of this situation. To do this, the psychometric paradigm method was adapted and a descriptive and multivariate analysis was carried out, which allowed knowing the social perception of the risk in the area that was considered more critical according to the results that emerged from the diagnosis of urban areas exposed to NIR emitted by MPBS located in the municipality of Cartago (Valle del Cauca). The results of the analyses show that the perception of each individual is based on intuitive judgments and sociocultural factors which result in attitudes and decisions made against the assessed risk which, apparently, in the social imaginary has not been conceived in its entirety as a potential risk factor. That is why, it can be concluded that judgments about the assessed risk differ not only individually but also collectively.
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Humanos , Pesqueiros , Artemia , Oceano Pacífico , ColômbiaRESUMO
Se realizó una búsqueda informativa a través de la consultoría BIOMUNDI relacionada con radiaciones electromagnéticas y afectaciones al estado de salud. El resultado de la búsqueda refleja la actualidad del tema y la importancia que se presta por los sistemas de salud a este aspecto que muchos han llamado la epidemia del desarrollo científico-tecnológico. Se confirma en muchas investigaciones la fuerte relación entre radiaciones electromagnéticas y cáncer
A information search was carried out in BIOMUNDI consultancy firm related to electromagnetic radiations and the affections to health status. Findings showed the subject updating and significance that health systems offer on this feature called the the epidemic of scientific-technological development. In many researches it is verified the strong relation between the electromagnetic radiations and the cancer
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Humanos , Impactos da Poluição na Saúde/efeitos adversos , Lesões por Radiação/prevenção & controle , Nível de SaúdeRESUMO
INTRODUCCION: La electricidad y las comunicaciones son aspectos sin los cuales es imposible la vida moderna; sin embargo, las radiaciones electromagnéticas (radiaciones no ionizantes) afectan la salud. De ahí que reviste gran importancia conocer la posible influencia que sobre el estatus oxidativo, la capacidad antioxidante y los niveles hemoquímicos pudiera ejercer la exposición a las ondas electromagnéticas no ionizantes. OBJETIVO: Valorar el comportamiento del ácido úrico, la albúmina y las proteínas totales en sujetos expuestos a las radiaciones electromagnéticas. MÉTODOS: Se realizó un estudio prospectivo, longitudinal y analítico de casos y controles en 125 sujetos del sexo masculino, con edades comprendidas entre 20 y 29 años. Se conformaron dos grupos de estudios: el primero formado por n = 63 sujetos expuestos (operan equipos de radiolocalización a través de radares) y el segundo grupo control formado por sujetos no expuestos a radiaciones ionizantes, n = 62. Para detectar diferencias significativas entre grupos fue utilizado el test T para muestras independientes. El nivel de significación fue de p ú 0,05. RESULTADOS: Al comparar ambos grupos, se observaron diferencias significativas en cuanto a los valores de proteínas totales y albúmina; sin embargo, los niveles de ácido úrico no sufrieron afectación. CONCLUSIONES: Los sujetos expuestos a radiaciones electromagnéticas no ionizantes en el orden de las supra altas frecuencias (SAF - 3 a 30 GHz) presentan un aumento significativo en los niveles de proteínas totales y de albúmina, lo cual pudiera afectar su capacidad de defensa antioxidante
INTRODUCTION: The electricity and communications are features essential in the modern life; however, the electromagnetic radiations (non-ionizing radiations affect the health. Hence, it is very important to know the potential influence that on the oxidative status, the antioxidant ability and the hemochemical levels could exert the exposition to non-ionizing electromagnetic radiations. OBJECTIVE: To assess the behavior of uric acid, the albumin and the total proteins in subjects exposed to electromagnetic radiations. METHODS: A analytical, longitudinal and prospective cases-controls study was conducted in 125 male subjects aged between 20 and 29. Two study groups were created: the first one included n= 63 exposed subjects (using radio location equipments by radar) and the second one included subjects non-exposed to ionizing radiations, n = 62. To detect significant differences among groups T test was used for independent samples. The significance level was of p ? 0,05. RESULTS: Comparing both groups it was possible to observe significant differences as regards total proteins and albumin values; however, the uric acid levels remained without affection. CONCLUSIONS: The subjects exposed to non0ionizing electromagnetic radiations in the order of very high frequencies (SAF - 3 to 30 GHz) had a significant increase in the total proteins and albumin levels, which could to affect its ability of antioxidant defense
Assuntos
Humanos , Masculino , Adulto , Ácido Úrico/efeitos da radiação , Albumina Sérica/efeitos da radiação , Proteínas Sanguíneas/efeitos da radiação , Estudos Longitudinais , Estudos ProspectivosRESUMO
La energía radiante abarca todo el espectro electromagnético y proviene de la fusión en el sol, de 4 núcleos de hidrógeno en uno de helio. Las radiaciones electromagnéticas tienen características de ondas, con la velocidad de la luz (c) y difieren en sus longitudes de ondas (λ). La energía lumínica es transmitida en unidades individuales o fotones: E = h c/λ así, los fotones de menores λs son los de mayor energía. Las radiaciones ultravioletas (UV) (λs de 200 - 400 nm) pueden dividirse: UVA (λs 315 - 400 nm); UVB (λs 280 - 315 nm) y UVC (λs < 280 nm). UVB y UVC son las más importantes, en inducir respuestas biológicas. Por acción de las radiaciones electromagnéticas el O2, da productos agrupados bajo la denominación de Especies Reactivas del Oxígeno (ROS). El alto contenido de O2 en los sistemas biológicos estimula la formación de ROS, que si no son controladas por el sistema endógeno de antioxidantes, afectan el estado redox de las células y generan daños tisulares ("stress oxidativo"). Inducen peroxidación de lípidos, entrecruzamiento de proteínas, inhibición de enzimas, pérdida de integridad y función de membranas plasmáticas y mitocondriales, ruptura de organelas intracelulares. Como consecuencias producen inflamación, envejecimiento, carcinogénesis y muerte celular. Mientras las radiaciones infrarrojas, inducen aumento de la temperatura cutánea, llegando a producir graves quemaduras, las UVA y UVB, en forma encubierta, reaccionan con cromóforos del tejido cutáneo, que absorben fotones y generan alteraciones fotoquímicas, implicadas en el envejecimiento celular e inducción de cáncer. La radiación UV al alcanzar el núcleo de las células causa daños en el ADN. Los seres humanos debemos protegernos de los efectos deletéreos del sol que representa un problema de salud pública, de suma importancia. Defensa que logramos con la vestimenta y uso de productos protectores de la piel. Las bacterias, así como otros procariotas, más expuestas a las radiaciones solares han generado plásmidos, que incrementan por medio de un sistema de reparación del ADN, la tolerancia a la UV y otros agentes mutagénicos.
The energy of electromagnetic radiation is derived from the fusion in the sun of four hydrogen nuclei to form a helium nucleus. The sun radiates energy representing the entire electromagnetic spectrum. Light is a form of electromagnetic radiation. All electromagnetic radiation has wave characteristics and travels at the same speed (c: speed of light). But radiations differ in wavelength (λ). Light energy is transmitted not in a continuum stream but only in individual units or photons: E = h c/λ. Short wave light is more energetic than photons of light of longer wavelength. Ultraviolet radiations (UV) (λs 200 - 400 nm) can be classified in UVA (λs 315 - 400 nm.); UVB (λs 280 - 315 nm) and UVC (λs < 280 nm). UVB and UVC are the most significant UV radiations to induce biological responses. Electromagnetic radiations on molecular oxygen lead to several reactive products known as Reactive Oxygen Species (ROS). High O2 content in biological systems promotes ROS synthesis. If ROS are not controlled by endogenous antioxidants, cell redox status is affected and tissue damage is produced ("oxidative stress"). ROS induce lipid peroxidation, protein cross-linking, enzyme inhibition, loss of integrity and function of plasmatic and mitochondrial membranes conducing to inflammation, aging, carcinogenesis and cell death. While infra-red radiations lead to noticeable tissue temperature conducing to severe burns, UVA and UVB undercover react with skin chromophores producing photochemical alterations involved in cellular aging and cancer induction. As UV radiations can reach cellular nucleus, DNA can be damage. Human beings need protection from the damaging sunbeams. This is a very important concern of public health. While humans need to protect their skin with appropriate clothing and/or by use of skin sunblocks of broad spectrum, some bacteria that are extensively exposed to sunlight have developed genomic evolution (plasmid-encoded DNA repair system) which confer protection from the damaging effect of UV radiation.