Interindividual differences in radiation-induced apoptosis of peripheral blood leukocytes in normal individuals and breast cancer patients

Quantification of radiation-induced apoptosis in peripheral blood lymphocytes [PBLs] has been proposed as a possible screening test for cancer-prone individuals and also for the prediction of normal tissue responses after radiotherapy. The neutral version of the comet assay [single-cell gel electrophoresis] was used 24, 48, 72 hours after irradiation with 8 Gy gamma rays to assess interindividual differences in gamma rays-induced apoptosis in peripheral blood leucocytes between a panel of 30 normal individuals, and 30 breast cancer patients who hadn't received radiotherapy or chemotherapy previously. Slides were stained with ethidium bromide and comets were assessed using visual and computer analysis. In all incubation times, the baseline and radiation induced apoptosis values were higher in breast cancer patients compared to normal individuals which were significantly different [p<0.01]. Although, both baseline and radiation induced values were higher in young breast cancer patients, the age did not seem to have a significant effect on apoptosis values both in cancer cases and controls. The increased rate of apoptosis observed in the leukocytes of breast cancer cases might be associated with their deficient DNA repair mechanisms. This finding might indicate that the radiation induced apoptosis could have some predictive potential. However, large interindividual variation has been a drawback. More studies are required to investigate the causes of interindividual variation and how it might be minimized

Hepatocytes, rather than leukocytes reverse DNA damage in vivo induced by whole body y-irradiation of mice, as shown by the alkaline comet assay

DNA damage repair was assessed in quiescent (G0) leukocytes and in hepatocytes of mice, after 1 and 2 hours recovery from a single whole body y-irradiation with 0.5, 1 or 2 Gy. Evaluation of single-strand breaks (SSB) and alkali-labile sites together were carried out by a single-cell electrophoresis at pH>13.0 (alkaline comet assay). In non-irradiated (control) mice, the constitutive, endogenous DNA damage (basal) was around 1.5 times higher in leukocytes than in hepatocytes. Irradiation immediately increased SSB frequency in both cell types, in a dose-dependent manner. Two sequential phases took place during the in vivo repair of the radio-induced DNA lesions. The earliest one, present in both hepatocytes and leukocytes, further increased the SSB frequency, making evident the processing of some primary lesions in DNA bases into the SSB repair intermediates. In a second phase, SSB frequency decreased because of their removal. In hepatocytes, such a frequency regressed to the constitutive basal level after 2 hours recovery from either 0.5 orí Gy. On the other hand, the SSB repair phase was specifically abrogated in leukocytes, at the doses and recovery times analyzed. Thus, the efficiency of in vivo repair of radio-induced DNA damage in dormant cells (lymphocytes) is quite different from that in hepatocytes whose low proliferation activity accounts only for cell renewal.

Determination of the effects of extremely low frequency electromagnetic fields on the percentages of peripheral blood leukocytes and histology of lymphoid organs of the mouse

To determine the effects of very weak, extremely low frequency [50 Hz] electromagnetic field [ELF-EMF] on the relative spleen weight, lymphoid organ histology, peripheral blood leukocyte and alpha-naphthyl acetate esterase positive [ANAE- positive] lymphocyte percentages of the mouse. The study was carried out in Scientific Research and Application Center of Selcuk University, Konya, Turkey in 2005. A total of 120 Swiss albino mice were divided into 6 groups [20 in each group]. The experimental animals were exposed to 1, 2, 3, 4 and 5 uT flux intensities [rms] of EMF at 50 Hz for 40 days. In the exposure groups with 20 animals, the body weight [BW] increased gradually in higher field intensities and reached at peak level in the 4 uT, and then slightly decreased. The relative spleen weight [% of the BW] was not affected. The ELF-EMF treatment did not cause any significant change in lymphocyte, monocyte and ANAE-positive lymphocyte ratios, whereas percentages of neutrophils and basophiles changed non-linearly. Any change in the lymphoid organ histology, which is attributable to the field effect, was not observed in the exposure groups. Extremely low frequency-EMF exposure with the flux intensities between 1-5 uT for 40 days did not cause any effect on the relative spleen weight, lymphoid organ histology, leukocyte and ANAE-positive lymphocyte percentages of the mouse

Effect of famotidine on radiation induced apoptosis in human peripheral blood leukocytes

Radioprotective effects of famotidine, an antagonist of H2 receptor clinically used for peptic ulcer treatment, was previously shown on radiation-induced micronuclei and chromosomal aberration in human peripheral blood lymphocytes and mouse bone marrow cells. This study was conducted to investigate radioprotective property of famotidine against radiation induced apoptosis in human peripheral blood leukocytes. Peripheral blood was obtained from 6 healthy volunteers including three males and three females. 12 microL of blood sample diluted in 1 ml RPMI-1640 supplemented with antibiotics and foetal calf serum was irradiated a dose of 8 Gy gamma rays generated from a Co-60 source at a dose rate of 1.27 Gy/min. After 48 h incubation in a 37 ?C incubator, cells embedded in low melting point agarose were transferred to a slide precoated with normal agarose. Cells were lysed and subjected to electrophoresis under neutral condition. Slides were then stained with ethidium bromide and analysed under a fluorescence microscope. 500 cells were analysed for each sample for the presence of apoptosis. The data were statistically evaluated using Man-Whitney non-parametric and ANOVA tests. Results show a significant increase in apoptosis induction following 8 Gy gamma-irradiation comparing with controls [p<0.001]. The presence of famotidine at 50 and 100 microg/ml did not show any protective effect against radiation induced apoptosis; however, the presence of famotidine at higher concentration [200 microg/ml] significantly deceased radiation induced apoptosis [p<0.001]. The obtained results suggest that famotidine suppresses radiation-induced apoptosis at 200 microg/ml, probably via OH radical scavenging and an intracellular antioxidation mechanism. Famotidine appears to be a useful candidate for the future development of post-irradiation radioprotectors

Peritoneal infection by Candida albicansL study of number and size limphocytes and phagocitic activity of peritoneal macrophages in mice

The main purpose of this investigation was to study some aspects of leucocytes (granulocytes and limphocytes) and the phagocitic activity of peritoneal macrophages. In this experiment, which took place at Escola Paulista de Medicina - Universidade Federal de SÒo Paulo - Brazil, it was used twenty female C57BLACK mice. Half of them were submitted to radiation to obtain immunossupressed animals (group A - irradiated mice). The other ten mice were not irradiated (Group B - control). The animals were sorted in four subgroups: A-1, A-2, B-1 and B-2. Mice of the groups A-1 and B-1 were injected with saline, and those the subgroups A-2 and B-2, were infected with Candida albicans (ATCC 90029). The resultant data showed significant differences in the number of leucocytes (granulocytes and limphocytes), and in the medium size of limphocytes between irradiated and non irradiated mice. Related to peritoneal macrophages, it was observed that the number of macrophages was lower in irradiated mice and the phagocitic activity was decreased in the irradiated and infected animals.

Detección de heterocigotos de ataxia telangiectasia por la sensibilidad a la radiación ionizante / Detection of heterocygotic with patients with ataxia telangiectasia show chromosomic rupture

Investigaciones recientes han demostrado que los pacientes homocigotos y heterocigotos de ataxia telangiectasia (AT) tienen rompimientos cromosómicos. De acuerdo con esta característica se diseñó el estudio inducido rompimientos cromosómicos en células granulocíticas de pacientes con diagnóstico de AT, heterocigotos obligados de AT y comparados con un grupo de individuos sanos. A todos los pacientes se les cuantificó el número de rompimientos cromosómicos con 14 dosis de radiación 125 kv, 125 mA. Los resultados sugieren diferencias significativas en el número de alteraciones estructurales cromosómicas inducidas por la radiación en los granulocitos de heterocigotos de ataxia telangiectasia similares a las alteraciones estructurales de los linfocitos de pacientes con AT y se demuestra que estas alteraciones se presentan preferentemente en un cromosoma del grupo C de homocigotos y heterocigotos de AT

Effects of whole-body x-irradiation on the peripheral blood of primate Cebus apella

The effects of ionizing radiation on the peripheral blood elements of primate Cebus apella were examined after a single 25.8mC/kg (100 R) dose of whole-body X-ray. We determined the number of white blood cells,neutrophils, osophils, basophils,lymphocytes,monocytes anderythrocytes up to 90 days after exposure of 5 animals. Hemoglobin content and microhematocrit were also determined. Under these experimental conditions, the total number of leukocytes was reduced from 9440/mm***3 to 5660/mm***3 on day6, mainly because of a decrease inthe lymphocyte population from 5843.2/mm***3 to 2349.0/mm***3 on day 6. No significant differences were observed in the values of erythrocytes, neutrophils,eosinophils,basophils,monocytes,hemoglobin content and microhematocrit. All hematological parameters studied returned tonormal values by day 90 after a single irradiation dose of 100R

Comparative study of different methods used to isolated Trypanosoma cruzi from defibrinated blood of irradiated mice

Different methods are being used for the isolation and purification of Trypanosoma cruzi blood forms from infected vertebrate hosts. In this study we compare four of these methods (differential centrifugation, Ficoll-Hypaque, Histopaque 1077 and metrizamide) in terms of parasite recovery rates, contamination with cells, duration of the process and role of host irradiation. male albino Swins mice irradiated in a Gamma Cell 220 (500 rads) were inoculated with CL and VL-10 T. cruzi strains and bled at the peak of parasitemia. Infected defibrinated blood was then used for the isolation. Although all methods permitted the recovery of viable trypomastigotes, the best results were obtained with Ficoll-Hypaque and Histopaque 1077. Recovery rates ranged between 71% to 88% and parasite-enriched preparations were obtained in approximately 75 min. irradiation and blood defibrination drastically reduced platelet and leukocyte contamination of the preparations

Alteraçöes hematológicas em camundongos da raça C57 BL expostos à irradiaçäo corpo-inteiro pelo cobalto radioativo / Hematologia changes in C57 BL mice exposed to whole body irradiation with radioactive cobalt

Sete grupos de 5 camundongos da raça B57 B1 submeteram-se à radiaçäo corpo-inteiro em dose única de 1.000 rads (285m C/Kg). Cada grupo foi sacrificado, respectivamente nos 1§, 3§, 5§, 7§, 8§, 9§ e 10§ dias após a exposiçäo à radiaçäo. Um 8§ grupo de 5 animais servia de controle, näo se submetendo à radiaçäo. Antes do sacrifício, colhia-se sangue periférico para a feitura de extensöes, as quais foram coradas pelo Leishman. Em seguida, retirava-se o fêmur E, para a realizaçäo de cortes de medula óssea. Verificou-se acentuada reduçäo dos elementos figurados do sangue, paralela a igual depressäo medular, que se fez progressivamente até o 10§ dia, quando a aplasia era quase total. Nessa ocasiäo, verificaram-se, na medula óssea, quase que exclusivamente, linfócitos, plasmócitos, fibroblastos e células endoteliais, além de raros megacariócitos, mantendo-se, entretanto, as plaquetas no sangue periférico em número proximamente normal