RESUMO
High natural-background radioactivity levels occur in the semi-arid region of the State of Rio Grande do Norte, northeastern Brazil. We have studied the lizard Phyllopezus periosus, an endemic species of the Brazilian caatinga with saxicolous habitat, as a bioindicator of environmental quality. Specimens were collected in three areas, an environmental protection area and two areas recognized as having high natural background radiation, one of these being a mining area. Level of metals and gamma radiation emitters present in the water sources potentially used by the lizards were measured. The biological endpoints assessed were micronuclei and nuclear abnormalities in blood samples. Significant differences in background radioactivity levels were found among the assessed areas. Statistically significant differences in micronuclei and nuclear abnormality frequencies were seen, among the study areas and a relationship between radioactivity level and genetic damage was observed.
Assuntos
Radiação de Fundo/efeitos adversos , Eritrócitos , Lagartos , Animais , Brasil , Núcleo Celular/genética , Núcleo Celular/metabolismo , Núcleo Celular/efeitos da radiação , Aberrações Cromossômicas/efeitos da radiação , Aberrações Cromossômicas/veterinária , Análise Citogenética/veterinária , Clima Desértico , Ecossistema , Monitoramento Ambiental , Eritrócitos/metabolismo , Eritrócitos/patologia , Eritrócitos/efeitos da radiação , Lagartos/sangue , Lagartos/genética , Testes de Mutagenicidade/veterinária , RadioatividadeRESUMO
Most women with breast cancer can become pregnant and give birth while undergoing radiation therapy and breastfeeding is generally not contraindicated. The induction of long-lived reactive species in proteins, such as casein by X-ray radiation and DNA damage to unexposed organisms, has been shown when ingesting irradiated cheese. To determine whether exposing lactating rats to X-rays increases the number of micronucleated erythrocytes (MNEs) in peripheral blood of their unexposed or breastfeeding rat pups, 15 female Wistar rats were divided into three groups: Negative control; Experimental group exposed to X-rays, and group exposed to X-rays plus vitamin C. The mothers of groups 2 and 3 were irradiated for three consecutive days after giving birth, returning them to their respective cages each time to continue lactation. A blood sample was taken from the mothers and pups at 0, 24, and 48 hr. Blood smears were stained with acridine orange to analyze MNEs. In mother rats, the frequency of micronucleated polychromatic erythrocytes (MNPCEs) increased significantly at 24 and 48 hr in both study groups exposed to radiation. Likewise, in rat pups the MNPCE and MNE frequencies increased in both groups with radiation and radiation plus vitamin C at 24 and 48 hr, and a protection from vitamin C was observed. In conclusion, the genotoxic damage produced in rat pups that were lactated by mothers irradiated with X-rays is possibly due to the effect of long-lived reactive species that were formed in the breast milk of female Wistar rats during the irradiation process.
Assuntos
Dano ao DNA/genética , Eritrócitos/efeitos da radiação , Lactação/efeitos da radiação , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Animais , Neoplasias da Mama/complicações , Neoplasias da Mama/radioterapia , Dano ao DNA/efeitos da radiação , Eritrócitos/patologia , Feminino , Lactação/genética , Masculino , Testes para Micronúcleos , Mães , Gravidez , Ratos , Ratos Wistar , Raios X/efeitos adversosRESUMO
Light pollution or artificial lighting at night (ALAN) is an emerging threat to biodiversity that can disrupt physiological processes and behaviors. Because ALAN stressful effects are little studied in diurnal amphibian species, we investigated if chronic ALAN exposure affects the leukocyte profile, body condition, and blood cell sizes of a diurnal toad. We hand-captured male toads of Melanophryniscus rubriventris in Angosto de Jaire (Jujuy, Argentina). We prepared blood smears from three groups of toads: "field" (toads processed in the field immediately after capture), "natural light" (toads kept in the laboratory under captivity with natural photoperiod), and "constant light" (toads kept in the laboratory under captivity with constant photoperiod/ALAN). We significantly observed higher neutrophil proportions and neutrophils to lymphocytes ratio in toads under constant light treatment. In addition, we observed significantly better body condition and higher erythrocyte size in field toads compared with captive toads. In summary, ALAN can trigger a leukocyte response to stress in males of the diurnal toad M. rubriventris. In addition, captivity can affect the body condition and erythrocyte size of these toads.
Assuntos
Composição Corporal/efeitos da radiação , Bufonidae/fisiologia , Eritrócitos/efeitos da radiação , Luz , Animais , Tamanho Celular/efeitos da radiação , Eritrócitos/citologia , MasculinoRESUMO
We evaluated the damage caused to optically trapped red blood cells (RBCs) after 1 or 2 min of exposure to near-infrared (NIR) laser beams at 785 or 1064 nm. Damage was quantified by measuring cell elasticity using an automatic, real-time, homemade, optical tweezer system. The measurements, performed on a significant number (hundreds) of cells, revealed an overall deformability decrease up to â¼104% after 2 min of light exposure, under 10 mW optical trapping for the 785-nm wavelength. Wavelength dependence of the optical damage is attributed to the light absorption by hemoglobin. The results provided evidence that RBCs have their biomechanical properties affected by NIR radiation. Our findings establish limits for laser applications with RBCs.
Assuntos
Eritrócitos/efeitos da radiação , Raios Infravermelhos , Lasers , Elasticidade , Hemoglobinas/metabolismo , Humanos , Pinças ÓpticasRESUMO
In previous studies, exposure to phototherapy, but not oxygen therapy, resulted in damage to genetic material in newborns. The objective of this study was to determine whether micronucleated erythrocytes (MNE) increased in preterm newborns (PNBs) who were exposed to blue light phototherapy lamps. MNE of mature organisms are rapidly eliminated by the spleen, and the presence of MNE has been related to immaturity in some species. Furthermore, PNBs present spontaneous MNE. Blood samples were taken from 17 PNBs at birth to establish baseline frequencies (0 h). After beginning blue light phototherapy, blood samples were obtained from 11 of these PNBs at 24-h intervals for 96 h, after the baseline sample. MNE and micronucleated polychromatic erythrocytes (MNPCE) were counted. The basal values of MNE and MNPCE from 17 PNBs were 0.62 ± 0.48 and 1.52 ± 1.28 (), respectively, and no increase in MNE or MNPCE was observed in the serial samples of 11 PNBs exposed to blue light and oxygen therapies, though previous studies reported increases using other types of lamps. In conclusion, under the conditions described no increase in the number of MNE or MNPCE was observed in the peripheral blood of PNBs exposed to blue light phototherapy.
Assuntos
DNA/metabolismo , Luz , DNA/química , Eritrócitos/citologia , Eritrócitos/efeitos da radiação , Feminino , Idade Gestacional , Humanos , Oxigenoterapia Hiperbárica , Hiperbilirrubinemia/terapia , Recém-Nascido , Recém-Nascido Prematuro , Masculino , FototerapiaRESUMO
BACKGROUND: In developing countries, the access to red blood cell (RBC) irradiators is restricted. Thus, it is a common practice in blood banks to stock irradiated RBC units until they expire. The aim of this work is to elucidate the involvement of Na,K-ATPase in potassium leakage from prophylactically irradiated RBCs. METHODS: Whole blood was collected from healthy donors, and blood concentrates were irradiated with 25Gy of γ-radiation within 24h of collection. At days 3, 5, 7, 9, 11, 14 and 28 post-irradiation, fractions were removed and centrifuged and Na,K-ATPase activity from ghost membranes was determined. RESULTS: The inhibition of Na,K-ATPase activity in RBCs reached 12.6% by day 7 of storage and up to 50% by day 14 of storage. The addition of vitamin C prevented the irradiation-induced loss of Na,K-ATPase activity. The irradiation of RBCs provoked an increase in potassium plasma levels and a decrease in sodium plasma levels. The incubation of RBCs with ouabain did not change the sodium or potassium levels in the plasma, and the addition of vitamin C only partially prevented a decrease in sodium levels caused by irradiation. CONCLUSION: Because the inhibition of Na,K-ATPase by ouabain did not cause potassium accumulation in the plasma, we conclude that the irradiation-induced inhibition of the pump is not a key factor driving this effect.
Assuntos
Eritrócitos/metabolismo , Eritrócitos/efeitos da radiação , Potássio/sangue , ATPase Trocadora de Sódio-Potássio/metabolismo , Manejo de Espécimes/métodos , Inibidores Enzimáticos/farmacologia , Humanos , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidoresRESUMO
An investigation into the effects of irradiation and of the storage time on aging and quality are a relevant issue to ensure the safety and the efficiency of irradiation in the prevention of transfusion-associated graft-versus-host disease (TA-GVHD). In this work, the biochemical properties and alterations presented by erythrocyte membranes, up to 28-days post-irradiation, with a dose of 25 Gy, were studied as a function of storage and post-irradiation time. There was a considerable variation in the total of phospholipid content, when comparing the control and irradiated samples, mostly from the third day onwards; and at the same time, the effect occurred as a function on the storage time of blood bags. The levels of total cholesterol decreased 3-9 days after irradiation. TBARS levels were increased after irradiation and 7 days of storage, but no increment of catalase activity was observed after the irradiation. Furthermore, the protein profile was maintained throughout the irradiation and storage time, until the 21st day, with the presence of a protein fragmentation band of around 28 kDa on the 28th day. In conclusion, although gamma irradiation is the main agent for the prevention of TA-GVHD, a better understanding of the physical and biochemical properties of erythrocytes are necessary to better assess their viability, and to be able to issue more secure recommendations on the shelf life of blood bags, and the safe use of the irradiated red cells therein.
Assuntos
Preservação de Sangue , Colesterol/química , Eritrócitos/efeitos da radiação , Raios gama , Fosfolipídeos/química , Catalase/metabolismo , Relação Dose-Resposta à Radiação , Membrana Eritrocítica/química , Membrana Eritrocítica/metabolismo , Membrana Eritrocítica/efeitos da radiação , Eritrócitos/química , Eritrócitos/metabolismo , Peroxidação de Lipídeos/efeitos da radiação , Lipídeos de Membrana/química , Oxirredução , Proteólise , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
The aim of the present work was to evaluate the redox and oligomeric effects associated with the human hemoglobin of stored red blood cells that had been previously submitted to gamma radiation. Whole blood was collected from healthy donors and irradiated with 25 Gy of γ-radiation within 24 h of collection. At days 3, 5, 7, 9, 11, 14, and 28 postirradiation, fractions were removed and centrifuged, and the levels of methehemoglobin and oxyhemoglobin were measured. Hb was isolated to measure the denaturation and UV-vis spectra. The results from electrophoresis demonstrated that there was no fragmentation or cross-linking of the hemoglobin. However, ferrous center oxidation was identified as a very significant process. This mechanism is likely through an autoxidation process of the ferrous heme center, which has a maximal intensity between 5 and 7 days of storage. Interestingly, a subsequent reduction of the oxidized heme species was observed, and after 9 days of storage, the difference between the ferric species present in the control and irradiated samples was not representative. This interesting fact suggests a type of "protective action" by the blood to control the oxidative stress generated by the gamma irradiation. The UV-vis measurements demonstrated that the oxidized species was predominantly formed by hemichrome species (bis-histidine ferric heme species), which are usually associated with Heinz bodies. After 28 days of storage, evidence from the UV-vis measurements indicated that the oxidation of the irradiated sample was much higher than that observed in the control sample. These results demonstrate that despite the minimal polypeptide changes observed in the hemoglobin of stored red blood cells after gamma irradiation, the oxidation of the heme metallic center is not irrelevant and must be controlled to improve the hematological clinical procedures associated with the storage of red blood cells.
Assuntos
Preservação de Sangue , Eritrócitos/efeitos da radiação , Raios gama/efeitos adversos , Hemoglobinas/efeitos da radiação , Procedimentos de Redução de Leucócitos/métodos , Eletroforese das Proteínas Sanguíneas , Heme/efeitos da radiação , Hemoglobinas/ultraestrutura , Humanos , Metemoglobina/análise , Oxirredução , Estresse Oxidativo , Oxiemoglobinas/análise , Conformação Proteica/efeitos da radiação , Desnaturação Proteica , Sulfa-Hemoglobina/análise , Fatores de TempoRESUMO
Preterm newborns (PNBs) have an immature antioxidant defense system, and this makes them more susceptible to oxidative stress generated by postnatal treatments. The objective was to determine whether micronucleated erythrocytes increase in PNB by postnatal treatments such as oxygentherapy and phototherapy. We counted micronucleated erythrocytes and micronucleated polychromatic erythrocytes as DNA damage in 72 blood samples of PNB at 26-36 weeks of gestation, taken between 1 and 84 h after birth. We assume that more time passed between sampling and birth would correspond to greater time of exposure to oxygen (37 cases) and phototherapy plus oxygen (35 cases). In the PNB only exposed to oxygen, the differences were not significant, while there was a significant increase in micronucleated polychromatic erythrocytes with increasing exposure time in those treated with phototherapy plus oxygen. In conclusion, our results suggest that the MN increase from phototherapy can be observed in peripheral blood erythrocytes of PNB.
Assuntos
Núcleo Celular/metabolismo , Eritrócitos/patologia , Oxigênio/efeitos adversos , Oxigênio/uso terapêutico , Fototerapia/efeitos adversos , Nascimento Prematuro/sangue , Nascimento Prematuro/terapia , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/efeitos da radiação , Dano ao DNA , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Eritrócitos/efeitos da radiação , Feminino , Humanos , Recém-Nascido , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Leucócitos Mononucleares/efeitos da radiação , Masculino , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Nascimento Prematuro/genética , Nascimento Prematuro/metabolismoRESUMO
Los eritrocitos son células útiles para la identificación de agentes potencialmente fototóxicos administrados por vía sistémica, así como para el estudio de los mecanismos de fototoxicidad que involucran procesos de estrés oxidativo. OBJETIVO: evaluar el efecto fotohemolítico de extractos blandos de partes aéreas de Cissus sicyoides L (Vitaceae) y Achyranthes aspera L (Amaranthaceae). MÉTODOS: se utilizó un protocolo in vitro que emplea como modelo biológico eritrocitos humanos, los que se irradian con luz ultravioleta durante 90 min para evaluar el daño en las membranas eritrocitarias, por detección de hemoglobina liberada al medio. RESULTADOS: se observó un leve grado de hemólisis, el efecto fotohemolítico fue inferior a los controles positivos. CONCLUSIONES: los extractos de las plantas se clasificaron como no irritantes, lo cual sugiere que la hemólisis observada puede ser causada por la inestabilidad de la membrana del eritrocito, debido a la presencia de diferentes metabolitos en los extractos estudiados
Erythrocytes are useful cells to identify potentially phototoxic agents provided by systemic administration as well as to study the phototoxicity mechanisms involving oxidative stress processes. OBJECTIVE: to evaluate the photohemolytic effect of soft extracts from aerial parts of Cissus sicyoides L (Vitaceae) and Achyranthes aspera L (Amaranthaceae). METHODS: an in vitro protocol using human erythrocytes as biological model; they were ultraviolet light-radiated for 90 minutes to evaluate damage in erythrocyte membranes on the basis of detected hemoglobin released into the medium. RESULTS: mild hemolysis was observed, being the photohemolytic effect lower than that of positive controls. CONCLUSIONS: the extracts from these plants were rated as non-irritating, which suggests that observed hemolysis may be caused by unstable erythrocyte membranes resulting from the existence of different metabolites in the studied extracts