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1.
Poult Sci ; 100(2): 467-473, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518098

RESUMO

Targeted green light photostimulation during the last stage of broiler incubation increases expression of the somatotropic axis. The purpose of this study was to further shorten the in ovo green light photostimulation and determine the critical age for photostimulation in broilers embryos, as a future strategy for broiler incubation. Fertile broilers eggs (n = 420) were divided into 5 treatment groups. The first group was incubated under standard conditions (in the dark) as the negative control group. The second was incubated under intermittent monochromatic green light using light-emitting diode lamps with an intensity of 0.1 W/m2 at shell level from embryonic day (ED) 0 of incubation until hatch, as a positive control. The third, fourth, and fifth groups were incubated under intermittent monochromatic green light from ED 15, 16, and 18 of incubation, respectively, until hatch. All treatment groups showed elevated somatotropic axis expression compared with the negative control, with the group incubated under monochromatic green light from ED 18 until hatch showing results closest to the positive control. This suggests that broiler embryos can be exposed to in ovo green light photostimulation from a late stage of incubation (when transferring the eggs to the hatchery) and exhibit essentially the same outcome as obtained by photostimulation during the entire incubation period.


Assuntos
Embrião de Galinha/efeitos da radiação , Somatotrofos/metabolismo , Animais , Embrião de Galinha/química , Hormônio do Crescimento/sangue , Hormônio Liberador de Hormônio do Crescimento/análise , Hormônios/análise , Hormônios/sangue , Hipotálamo/metabolismo , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Luz , Fígado/química , Óvulo/efeitos da radiação , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Somatotrofos/efeitos da radiação , Fatores de Tempo
2.
Childs Nerv Syst ; 34(5): 933-938, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29392421

RESUMO

PURPOSE: We aimed to determine whether varying the magnetic field during magnetic resonance imaging would affect the development of chicken embryos and neural tube defects. METHODS: Following incubation for 24 h, we exposed chicken embryos to varying magnetic fields for 10 min to assess the impact on development. Three magnetic resonance imaging devices were used, and the eggs were divided into four groups: group 1 is exposed to 1 T, group 2 is exposed to 1.5 T, group 3 is exposed to 3 T, and group 4, control group, was not exposed to magnetic field. After MRI exposure, all embryos were again put inside incubator to complete 48 h. "The new technique" was used to open eggs, a stereomicroscope was used for the examination of magnified external morphology, and each embryo was examined according to the Hamburger and Hamilton chicken embryo stages. Embryos who had delayed stages of development are considered growth retarded. Growth retardation criteria do not include small for stage. RESULTS: Compared with embryos not exposed to a magnetic field, there was a statistically significant increase in the incidence of neural tube closure defects and growth retardation in the embryos exposed to magnetic fields (p < 0.05). However, although the incidence of neural tube closure defects was expected to increase as exposure (tesla level) increased, we found a higher rate of defects in the 1.5-T group compared with the 3-T group. By contrast, the highest incidence of growth retardation was in the 3-T group, which was consistent with our expectation that growth retardation would be more likely as tesla level increased. CONCLUSIONS: We therefore conclude that the use of magnetic resonance imaging as a diagnostic tool can result in midline closure defects and growth retardation in chicken embryos. We hypothesize that this may also be true for human embryos exposed to MRI. If a pregnant individual is to take an MRI scan, as for lumbar disc disease or any other any other reason, our results indicate that consideration should be given to an avoidance of MRI during pregnancy.


Assuntos
Embrião de Galinha/efeitos da radiação , Desenvolvimento Embrionário/efeitos da radiação , Campos Magnéticos/efeitos adversos , Imageamento por Ressonância Magnética/efeitos adversos , Defeitos do Tubo Neural/etiologia , Tubo Neural/efeitos da radiação , Animais , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Tubo Neural/diagnóstico por imagem , Tubo Neural/embriologia , Defeitos do Tubo Neural/diagnóstico por imagem
3.
Explore (NY) ; 12(6): 451-454, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27659005

RESUMO

BACKGROUND: Modern living is awash with low-frequency electromagnetic radiation raising concern over health effects, birth defects, and infant cancers especially leukemias. Medical/scientific opinion is ambivalent, especially regarding possible mechanisms of action despite our bodies׳ many electric currents. AIMS: Are some cancers induced by morphogenetic changes rather than direct mutation? We wished to see if morphogenetic effects of weak, extremely low-frequency electric (ELF) fields in embryonated hen׳s eggs could induce cancers, knowing that such treatment is usually deleterious. We report a pilot study intended to reveal a promising cell source in which to search for cancer cells by established methods and then to check for DNA damage. METHODS: Stored (5°C for 1-36 days) fresh, fertile hens׳ eggs were incubated (38°C, total five or six days) in presence or absence of a weak ELF oscillating electric field (1-40V/cm, 1-50Hz and two to six days). Separated embryos were assessed for development stage. RESULTS: Storage of untreated eggs (>12 days, 5°C) allows a steady loss of normal embryo formation at 38°C (few viable by 25 days, half-life ~18 days). Surprisingly, incubation in a weak ELF field during the period of declining viability significantly (P: 0.03-0.0001) improved viability and condition of the embryos (new half-life ~21 days), rather than the expected converse. Thus for a few days, the field could keep viable some embryos that would otherwise not have survived. CONCLUSIONS: The rescued embryos and their untreated controls seem the most promising place to seek any carcinogenic effects of ELF fields. The nature of the presumed critical component keeping them viable during 5°C storage is at least of equal interest.


Assuntos
Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos , Animais , Estudos de Casos e Controles , Radiação Eletromagnética , Projetos Piloto
4.
Int. j. morphol ; 27(4): 1003-1008, dic. 2009. ilus
Artigo em Inglês | LILACS | ID: lil-582042

RESUMO

The Laser used correctly in the medical practice offers clear advantages compared with traditional therapies. The improvement and even the elimination of many significant skin lesions can be achieved with reduced risks to patients. However, it is important to keep security measures and understand the possible effects on an experimental model. The chick embryo is a good model to evaluate the direct effects of non-ionizing radiation for its easy handling and availability. The purpose of this communication is to show our histological findings in organs of the chick embryo with and without protective barrier to be subjected to radiation excimer. We used the following issuers: intense pulsed light (excimer Xe-Cl laser of 308 nm wavelength). It was irradiated embryos through an open window on eggshells. Aseptically the eggs were kept for 24 hours in an incubator. The protective barriers were used with and without colored glass, latex, cellophane, paper, polycarbonate of different colors and thicknesses. The most outstanding results, with no barrier and barriers with transparent and green were intense marked congestion in capillaries, edema and focus the necrosis. We concluded that the tissue changes observed are consistent with possible side effects of these radiations fototérmicos we warned about possible side effects when they are applied indiscriminately. We believe it is important to explore different means to safeguard the safety of operators and patients.


El láser utilizado correctamente en la práctica médica ofrece claras ventajas cuando se compara con las terapias tradicionales. La mejoría e incluso la eliminación significativa de muchas lesiones cutáneas se pueden lograr con riesgos reducidos para los pacientes. Sin embargo, es importante guardar medidas de seguridad y conocer los posibles efectos en un modelo experimental. El embrión de pollo es un buen modelo para evaluar los efectos directos de radiaciones no ionizantes por su fácil manipulación y disponibilidad. El objetivo del presente trabajo es comunicar los cambios histopatológicos en órganos del embrión de pollo con y sin barrera de protección al ser sometido a radiación excimer. Se utilizó el siguiente elemento emisor: luz pulsada intensa (Xe-Cl excimer laser de 308 nm de longitud de onda. Se irradiaron los embriones a través de una ventana abierta en la cáscara del huevo. Los huevos fueron mantenidos asépticamente por 24 hs en una incubadora. Las barreras de protección utilizadas fueron vidrio con y sin color, latex, celofán, papel, policarbonato de diferentes colores y espesores. Los resultados más sobresalientes, sin barrera y con barreras transparentes y de color verde fueron: intensa vasocongestión, edema y focosde necrosis. Se concluye que las modificaciones tisulares observadas son compatibles con posibles efectos fototérmicos colaterales de estas radiaciones los que nos advierten sobre posibles efectos adversos cuando las mismas se aplican indiscriminadamente. Creemos que es de importancia estudiar los diferentes medios que permitan resguardar la seguridad de los pacientes y operadores.


Assuntos
Animais , Embrião de Galinha , Cartilagem/efeitos da radiação , Embrião de Galinha/efeitos da radiação , Embrião de Galinha/patologia , Lasers de Excimer/efeitos adversos , Língua/efeitos da radiação , Modelos Biológicos , Necrose , Lasers/efeitos adversos
5.
J Radiat Res ; 50(6): 487-94, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19680012

RESUMO

To observe the sequential radiation-induced apoptosis in a living embryo, we injected Acridine Orange (AO) solution into the yolk of embryo and visualized radiation-induced apoptosis in developing optic tectum (OT). Medaka embryos at stage 28, when neural cells proliferate rapidly in the OT, were irradiated with 5 Gy X-rays which is a non-lethal dose for irradiated embryos at hatching. The irradiated embryos hatched normally without morphological abnormalities in their brains, even though a large number of apoptotic cells were induced transiently in OT. By yolk injection, apoptotic cells in OT were distinguished as AO-positive small nuclei at 3 h after irradiation. At 8-10 h after irradiation, AO-positive rosette-shaped clusters were obviously distinguished in marginal tectal regions of OT where cells are proliferating intensely. The AO-positive clusters became bigger and more obvious, but the number did not increase up to 24 h after irradiation and completely disappeared up to 49 h after irradiation. This characteristic appearance of the AO-positive nuclei/clusters is in good agreement with our previous results, based on the examination of fixed specimens stained with AO by injection into the peri-vitelline space, suggesting that the AO-yolk injection method is highly reliable for detecting apoptotic cells in living embryos. The live imaging of apoptotic cells in developing Medaka embryos by AO-yolk injection method is expected to reveal more of the details of the dynamics of apoptotic responses in the irradiated brain and other tissues.


Assuntos
Laranja de Acridina , Apoptose/efeitos da radiação , Embrião de Galinha/citologia , Embrião de Galinha/efeitos da radiação , Aumento da Imagem/métodos , Colículos Superiores/citologia , Colículos Superiores/efeitos da radiação , Animais , Galinhas , Colículos Superiores/embriologia
6.
Congenit Anom (Kyoto) ; 49(1): 15-9, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19243412

RESUMO

The possible adverse effects of radiofrequency electromagnetic fields (EMF) emitted from mobile phones present a major public concern. Biological electrical activities of the human body are vulnerable to interference from oscillatory aspects of EMF, which affect fundamental cellular activities, in particular, the highly active development process of embryos. Some studies highlight the possible health hazards of EMF, while others contest the hypothesis of biological impact of EMF. The present study was designed to observe the histomorphological effects of EMF emitted by a mobile phone on the retinae of developing chicken embryos. Fertilized chicken eggs were exposed to a ringing mobile set on silent tone placed in the incubator at different ages of development. After exposure for the scheduled duration the retinae of the embryos were dissected out and processed for histological examination. The control and experimental embryos were statistically compared for retinal thickness and epithelial pigmentation grades. Contrasting effects of EMF on the retinal histomorphology were noticed, depending on the duration of exposure. The embryos exposed for 10 post-incubation days exhibited decreased retinal growth and mild pigmentation of the epithelium. Growth retardation reallocated to growth enhancement on increasing EMF exposure for 15 post-incubation days, with a shift of pigmentation grade from mild to intense. We conclude that EMF emitted by a mobile phone cause derangement of chicken embryo retinal differentiation.


Assuntos
Diferenciação Celular/efeitos da radiação , Telefone Celular , Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Ondas de Rádio , Retina/embriologia , Retina/patologia , Animais , Galinhas
7.
J Ayub Med Coll Abbottabad ; 21(1): 130-4, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20364761

RESUMO

BACKGROUND: The possible adverse effects of Electromagnetic Fields (EMFs) emitted from mobile phones present a major public concern today. Some studies indicate EMFs effects on genes, free radical production, immunological and carcinogenic effects. On the other hand there are studies which do not support the hypothesis of any biological impacts of EMFs. This study was designed to observe the effects of mobile phone induced EMFs on survival and general growth and development of chick embryo, investigating dose-response relationship if any. METHODS: This was an experimental study in which developing chick embryos were exposed to different doses of mobile phone induced EMFs. For this purpose a mobile phone was placed in the incubator in the centre of fertilised eggs in silent ringing mode and was 'rung' upon from any other line or cell phone. After incubation for 10 or 15 days the eggs were opened and the developmental mile-stones of the surviving embryos were compared with the non exposed subgroup. RESULTS: EMFs exposure significantly decreased the survivability of the chick embryos. The lower doses of EMFs caused growth retardation. However, this effect of growth retardation reallocated to partial growth enhancement on increasing the dose of EMFs and shifted over to definite growth enhancement on further raising the dose. CONCLUSION: There is an adverse effect of EMFs exposure on embryo survivability. Chick embryos developmental process is influenced by EMFs. However, these effects are variable depending upon the dose of EMFs exposure.


Assuntos
Telefone Celular , Embrião de Galinha/crescimento & desenvolvimento , Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Animais , Relação Dose-Resposta à Radiação , Distribuição Aleatória
9.
Electromagn Biol Med ; 26(2): 73-81, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17613035

RESUMO

We report on a study where 4-day old chicken embryos from different flocks were pre-treated with 50 Hz magnetic fields (MF) prior to a 60-min UV-C exposure (1.7 mW/cm(2)) to investigate the possible protective effect of MF exposure on UV-induced embryo death. Different flux densities (0.010, 0.025, 0.050, 0.10, and 0.20 mT), field directions (vertical and horizontal), as well as MF exposure times (10, 20, and 60 min) were employed. We did not find any significant effects by MF exposure, irrespective of exposure time, flux density, or field direction on the survival of embryos. Neither could we find any flock dependency on sensitivity to MF exposure.


Assuntos
Embrião de Galinha/efeitos da radiação , Lesões por Radiação/prevenção & controle , Raios Ultravioleta , Animais , Campos Eletromagnéticos , Morte Fetal/etiologia , Morte Fetal/prevenção & controle , Fatores de Tempo
10.
Electromagn Biol Med ; 26(2): 83-98, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17613036

RESUMO

We investigated the effects of an electromagnetic field (EMF) of 50 Hz, 1.33-7.32 mT on sections of preincubated white leghorn chicken embryos using light, SEM and TEM microscopes. Five hundred healthy, fresh, and fertilized eggs (55-65 g) were divided into three groups of experimental (n = 18-20), control (n = 60), and sham (n = 50). Experimental eggs (inside the coil) were exposed to 15 different intensities (1.33-7.32 mT) for morphological surveys and to the known most effective intensities for light, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. Sham groups were located inside the same coil with no exposure for 24 h before incubation. Control, sham, and experimental groups were then incubated in an incubator (38 +/- 0.5 degrees C, 60% humidity) for 4 days. At the end of this period, embryos were removed from their shells, prepared for morphometric, light, and SEM/TEM studies. Results of light microscopic studies (serial sections, 6mu) and morphometric data showed significant differences between different groups (P < 0.005). Larger and abnormal brain cavities, spina bifida, monophthalmia, microphthalmia, anophthalmia, and growth retardation were shown on SEM. TEM sections demonstrated that the nucleus was condensed, the nuclear envelope disappeared, and mitochondria degenerated. Golgi apparatus and endoplasmic reticulum were the least affected organelles. The Telencephlon was the most affected region, and the retina was altered more than the lens. We conclude that EMFs affect the brain, especially the Telencephalon and eye of preincubated-exposed chick embryo at the morphological and cellular level, nuclei are the most affected part, and our data agrees with "Ubeda's windows effects" of EMFs on preincubated chick embryos.


Assuntos
Encéfalo/embriologia , Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos , Animais , Encéfalo/efeitos da radiação , Núcleo Celular/efeitos da radiação , Retículo Endoplasmático/efeitos da radiação , Complexo de Golgi/efeitos da radiação , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão/métodos , Fatores de Tempo
11.
Photomed Laser Surg ; 24(1): 29-32, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16503785

RESUMO

OBJECTIVE: We assessed the effect of 670-nm light therapy on dioxin-induced embryonic mortality in chickens (Gallus gallus). BACKGROUND DATA: Developmental photobiomodulation using 670-nm light-emitting diode (LED) arrays improves hatching success and increases body size in hatchling chickens. Photobiomodulation also stimulates signaling pathways resulting in improved energy metabolism, antioxidant production and cell survival. Dioxin causes embryonic mortality, including increases in the frequency of chicken embryos that pip but can't go to hatch. We hypothesized that 670-nm LED therapy would attenuate dioxin-induced embryo mortality. METHODS: Fertile chicken eggs were injected with control or 2, 20, or 200 ppt 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) prior to the start of incubation. Half of the eggs in each dose group were treated once per day from embryonic days 0-20 with 670-nm LED light at a fluence of 4 J/cm(2). In ovo survival and hatching success were compared between dose groups and LED treatment. RESULTS: LED therapy decreased the embryonic mortality rate by 41%, resulting in increased embryonic survival and improved hatching success in eggs exposed to 200 ppt dioxin. However, at sub-lethal dioxin concentrations and in oil-treated controls, LED therapy slightly increased mortality. CONCLUSION: Overall survivorship and hatching success of chicks developmentally exposed to dioxin concentrations above the lethality threshold (>100 ppt TCDD) is improved by 670-nm LED treatment administered throughout the gestation period, but the relationship may be complicated by an LED-oil interaction.


Assuntos
Embrião de Galinha/crescimento & desenvolvimento , Embrião de Galinha/efeitos da radiação , Fototerapia , Dibenzodioxinas Policloradas/toxicidade , Teratogênicos/toxicidade , Animais
12.
Photomed Laser Surg ; 23(3): 268-72, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15954813

RESUMO

OBJECTIVE: The objective of the present study was to assess the survival and hatching success of chickens (Gallus gallus) exposed in ovo to far-red (670-nm) LED therapy. BACKGROUND DATA: Photobiomodulation by light in the red to near-infrared range (630-1000 nm) using low-energy lasers or light-emitting diode (LED) arrays has been shown to accelerate wound healing and improve recovery from ischemic injury. The mechanism of photobiomodulation at the cellular level has been ascribed to the activation of mitochondrial respiratory chain components resulting in initiation of a signaling cascade that promotes cellular proliferation and cytoprotecton. MATERIALS AND METHODS: Fertile chicken eggs were treated once per day from embryonic days 0-20 with 670-nm LED light at a fluence of 4 J/cm2. In ovo survival and death were monitored by daily candling (after Day 4). RESULTS: We observed a substantial decrease in overall and third-week mortality rates in the light-treated chickens. Overall, there was approximately a 41.5% decrease in mortality rate in the light-treated chickens (NL: 20%; L: 11.8%). During the third week of development, there was a 68.8% decrease in the mortality rate in light-treated chickens (NL: 20%; L: 6.25%). In addition, body weight, crown-rump length, and liver weight increased as a result of the 670-nm phototherapy. Light-treated chickens pipped (broke shell) earlier and had a shorter duration between pip and hatch. CONCLUSION: These results indicate that 670-nm phototherapy by itself does not adversely affect developing embryos and may improve the hatching survival rate.


Assuntos
Embrião de Galinha/efeitos da radiação , Luz , Organogênese/efeitos da radiação , Animais , Peso Corporal , Estatura Cabeça-Cóccix , Fototerapia
13.
Artigo em Inglês | MEDLINE | ID: mdl-12413213

RESUMO

The study considers the influence of non-ionic radiation (white and monochromatic light) on the hatching of the Hampshire breed chickens. The chicken embryos were most sensitive to the white light (El), reaching the hatching time of 503.63 +/- 3.17 h, the hatchability of 95.12 +/- 3.72% and an average weight of incubated chickens 46.83 +/- 2.82 g. Of the monochromatic lights, the chicken embryos were most sensitive to yellow and green lights (E5, E4) with the hatching time of 505.22 +/- 4.03 and 507.14 +/- 3.95 h, respectively, the hatchability of 94.89 +/- 3.02 and 94.47 +/- 2.93%, respectively and the average weight of incubated chickens 45.72 +/- 1.93 and 45.05 +/- 2.66 g, respectively. The least reaction of chicken was observed with violet light (E2) with the hatching time of 510.04+/- 1.97 h, hatchability of 90.81 +/- 4.05% and the average weight of incubated chickens 42.02 +/- 3.72 g. The effect of violet light brings the same results as we observed in the case of hatching in darkness (control group C), when the hatching time was 510.41 +/- 2.82 h, hatchability 90.42 +/- 3.35% and average weight of incubated chickens 41.98 +/- 3.05 g.


Assuntos
Embrião de Galinha/crescimento & desenvolvimento , Embrião de Galinha/efeitos da radiação , Luz/efeitos adversos , Animais , Peso Corporal , Ovos
14.
Reprod Toxicol ; 15(2): 111-6, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11297869

RESUMO

Photodynamic therapy (PDT) of malignant processes is based on the ability of a photosensitizer to first, accumulate in malignant (immature) tissue and second, to be destroyed following light irradiation. Because of the similarity between malignant and embryonic immature tissues, we investigated the deleterious effect of the PDT procedure on day 4 chick embryos in ovo. We compared experimentally the photodynamic effect (light-toxic) and the side effect (dark-toxic) of the clinically attractive photosensitizers 5-aminolevulinic acid (ALA) and protoporphyrin IX (PP IX). The dark and light embryotoxicity (i.e. lethality plus teratogenicity) was determined after intra-amniotic injection of one of a range of dose of each compound. Under dark conditions, PP IX exhibited embryotoxicity at a dose of 10 microg/embryo; however ALA did not exhibit embryotoxicity even at the highest dose (300 microg/embryo). Light irradiation of embryos following injection induced strong embryotoxic effects of both substances even at dark-ineffective doses.


Assuntos
Anormalidades Induzidas por Medicamentos , Ácido Aminolevulínico/toxicidade , Embrião de Galinha/efeitos dos fármacos , Embrião de Galinha/efeitos da radiação , Perda do Embrião/induzido quimicamente , Luz/efeitos adversos , Fármacos Fotossensibilizantes/toxicidade , Protoporfirinas/toxicidade , Ácido Aminolevulínico/administração & dosagem , Animais , Escuridão/efeitos adversos , Relação Dose-Resposta a Droga , Lipossomos , Fármacos Fotossensibilizantes/administração & dosagem , Protoporfirinas/administração & dosagem
15.
Radiats Biol Radioecol ; 38(2): 223-31, 1998.
Artigo em Russo | MEDLINE | ID: mdl-9633625

RESUMO

EMF of power density from 0.4 to 10 mW/cm2 can influence forming the memory (imprinting). Showed the possibility to fix EMF modulated in embryonic brain during the natal period and conservation of this information after birth.


Assuntos
Campos Eletromagnéticos , Fixação Psicológica Instintiva/efeitos da radiação , Fatores Etários , Animais , Animais Recém-Nascidos , Encéfalo/efeitos da radiação , Embrião de Galinha/efeitos da radiação , Galinhas , Incubadoras
16.
Bioelectromagnetics ; 18(6): 431-8, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9261540

RESUMO

Several investigators have reported robust, statistically significant results that indicate that weak (approximately 1 microT) magnetic fields (MFs) increase the rate of morphological abnormalities in chick embryos. However, other investigators have reported that weak MFs do not appear to affect embryo morphology at all. We present the results of experiments conducted over five years in five distinct campaigns spanning several months each. In four of the campaigns, exposure was to a pulsed magnetic field (PMF); and in the final campaign, exposure was to a 60 Hz sinusoidal magnetic field (MF). A total of over 2500 White Leghorn chick embryos were examined. When the results of the campaigns were analyzed separately, a range of responses was observed. Four campaigns (three PMF campaigns and one 60 Hz campaign) exhibited statistically significant increases (P > or = 0.01), ranging from 2-fold to 7-fold, in the abnormality rate in MF-exposed embryos. In the remaining PMF campaign, there was only a slight (roughly 50%), statistically insignificant (P = 0.2) increase in the abnormality rate due to MF exposure. When the morphological abnormality rate of all of the PMF-exposed embryos was compared to that of all of the corresponding control embryos, a statistically significant (P > or = .001) result was obtained, indicating that PMF exposure approximately doubled the abnormality rate. Like-wise, when the abnormality rate of the sinusoid-exposed embryos was compared to the corresponding control embryos, the abnormality rate was increased (approximately tripled). This robust result indicates that weak EMFs can induce morphological abnormalities in developing chick embryos. We have attempted to analyze some of the confounding factors that may have contributed to the lack of response in one of the campaigns. The genetic composition of the breeding stock was altered by the breeder before the start of the nonresponding campaign. We hypothesize that the genetic composition of the breeding stock determines the susceptibility of any given flock to EMF-induced abnormalities and therefore could represent a confounding factor in studies of EMF-induced bioeffects in chick embryos.


Assuntos
Anormalidades Induzidas por Radiação , Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos , Indução Embrionária/efeitos da radiação , Análise de Variância , Animais , Embrião de Galinha/fisiologia , Suscetibilidade a Doenças , Relação Dose-Resposta à Radiação , Defeitos do Tubo Neural/embriologia , Defeitos do Tubo Neural/etiologia
17.
Toxicol Lett ; 88(1-3): 313-6, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8920754

RESUMO

The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation.


Assuntos
Anormalidades Induzidas por Medicamentos/prevenção & controle , Embrião de Galinha/efeitos dos fármacos , Embrião de Galinha/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Teratogênicos/toxicidade , Animais , Embrião de Galinha/anormalidades , Insulina/toxicidade , Tetraciclina/toxicidade , Raios X/efeitos adversos
18.
Zentralbl Veterinarmed A ; 42(2): 81-90, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8592891

RESUMO

Chicken embryos were X-irradiated with a dose of 8 Gy. At a developmental stage of 15 days, desoxyribonucleic acid (DNA) synthesis, nucleoid sedimentation, viscosity of the alkaline cell lysates and DNA fragmentation were examined in brain and/or liver cells. Further studies aimed at the appearance of acid-soluble nucleic acid metabolites in the allantoic fluid. Complementary investigations comprised the in vitro activities of a DNase I and a DNase II of liver and brain cells as well as of the allantoic fluid of X-irradiated embryos. It could be shown for the first time that, following acute X-irradiation of the chicken embryo, the inhibition of DNA synthesis is accompanied by at least two enzymatic DNA degradation phases. The early phase comprises a period of 6 (-12) h, whereas the second phase lasts, with organ-specific peculiarities, > or = 24 h. During the early period, some apoptotic phenomena are seen, whereas at the later stages of radiation response signs of necrolysis become evident. The excretion of DNA metabolites, probably oligonucleotides, in the allantoic fluid is enhanced following X-irradiation > 2 Gy and may be used as an additional parameter of the overall radiation damage. Therefore, the chicken embryo may be regarded as a radiobiological and possibly toxicological alternative to laboratory animals with respect to the nucleic acid metabolism.


Assuntos
Embrião de Galinha/efeitos da radiação , Dano ao DNA , DNA/biossíntese , DNA/efeitos da radiação , Desenvolvimento Embrionário e Fetal/efeitos da radiação , Alantoide/química , Animais , Encéfalo/embriologia , Encéfalo/efeitos da radiação , Química Encefálica , DNA/análise , Desoxirribonucleases/análise , Feminino , Fígado/química , Fígado/embriologia , Fígado/efeitos da radiação , Ratos , Ratos Wistar , Timo/citologia , Timo/efeitos da radiação
19.
Radiats Biol Radioecol ; 34(3): 375-8, 1994.
Artigo em Russo | MEDLINE | ID: mdl-8069371

RESUMO

Dynamics of changes in synthesis of cytoplasmatic and mitochondrial proteins in liver of chickens of various age exposed to low dose (0.05 Gy) ionizing radiation has been studied. It has been shown that low dose intensified the incorporation of labeled amino acids into the proteins in all the stages studied, although the degree and character of protein synthesis activation in cytoplasma and mitochondria are different. It is suggested that preincubation irradiation activates translational processes in cell, being one of the most important mechanisms of general stimulating effect of low doses.


Assuntos
Fígado/efeitos da radiação , Biossíntese de Proteínas , Radiação Ionizante , Fatores Etários , Animais , Embrião de Galinha/efeitos da radiação , Galinhas , Citoplasma/metabolismo , Citoplasma/efeitos da radiação , Fígado/metabolismo , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/efeitos da radiação , Doses de Radiação
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