Effects Of X-irradiation Research Articles

Differential effects of alpha-particle radiation and x-irradiation on genes associated with apoptosis.

This study examined differential effects of alpha-(α-) particle radiation and X-rays on apoptosis and associated changes in gene expression. Human monocytic cells were exposed to α-particle radiation and X-rays from 0 to 1.5 Gy. Four days postexposure, cell death was measured by flow cytometry and 84 genes related to apoptosis were analyzed using real-time PCR. On average, 33% of the cells were apoptotic at 1.5 Gy of α-particle radiation. Transcript profiling showed statistical expression of 15 genes at all three doses tested. Cells exposed to X-rays were <5% apoptotic at ~1.5 Gy and induced less than a 2-fold expression in 6 apoptotic genes at the higher doses of radiation. Among these 6 genes, Fas and TNF-α were common to the α-irradiated cells. This data suggests that α-particle radiation initiates cell death by TNF-α and Fas activation and through intermediate signalling mediators that are distinct from X-irradiated cells.

Effects of X-irradiation on proliferation and differentiation of neural stem cells derived from mouse embryonic stem cells

Effects of X-irradiation on proliferation and differentiation of neural stem cells derived from mouse embryonic stem cells

The Effects of X-Irradiation on Ex Vivo Expansion of Cryopreserved Human Hematopoietic Stem/Progenitor Cells

In our previous study (Life Sciences 84: 598, 2009), we demonstrated that placental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells have the effect to support the regeneration of freshly prepared X-irradiated hematopoietic stem/progenitor cells (HSPCs). Generally, HSPCs are supplied from companies, institutions, and cell banks that cryopreserve them for clinical and experimental use. In this study, the influence of cryopreservation on the responses of HSPCs to irradiation and co-culture with stromal cells is assessed. After cryopreservation with the optimal procedure, 2 Gy-irradiated HSPCs were cultured with or without stromal cells supplemented with combination of interleukin-3, stem cell factor, and thrombopoietin. The population of relatively immature CD34(+)/CD38(-) cells in cryopreserved cells was significantly higher than in fresh cells prior to cryopreservation; furthermore, the hematopoietic progenitor populations of CD34(+)/CD45RA(+) cells and CD34(+)/CD117(+) cells in cryopreserved cells were significantly lower than that in fresh cells. However, the rate of expansion in the cryopreserved HSPCs was lower than in the fresh HSPCs. In the culture of cryopreserved cells irradiated with 2 Gy, the growth rates of CD34(+) cells, CD34(+)/CD38(-) cells, and hematopoietic progenitors were greater than growth rates of their counterparts in the culture of fresh cells. Surprisingly, the effect to support the hematopoiesis in co-culture with stromal cells was never observed in the X-irradiated HSPCs after cryopreservation. The present results demonstrated that cryopreserving process increased the rate of immature and radio-resistant HSPCs but decreased the effects to support the hematopoiesis by stromal cells, thus suggesting that cryopreservation changes the character of HSPCs.

The effect of x-irradiation on the diphtheria antitoxin formation in rabbits.

Acta Pathologica Microbiologica ScandinavicaVolume 37, Issue 1 p. 94-98 THE EFFECT OF X-IRRADIATION ON THE DIPHTHERIA ANTITOXIN FORMATION IN RABBITS G. LAURELL, G. LAURELL THE INSTITUTE OF HYGIENE AND BACTERIOLOGY, UPPSALASearch for more papers by this authorB. SCHUBACK, B. SCHUBACK THE INSTITUTE OF HYGIENE AND BACTERIOLOGY, UPPSALASearch for more papers by this author G. LAURELL, G. LAURELL THE INSTITUTE OF HYGIENE AND BACTERIOLOGY, UPPSALASearch for more papers by this authorB. SCHUBACK, B. SCHUBACK THE INSTITUTE OF HYGIENE AND BACTERIOLOGY, UPPSALASearch for more papers by this author First published: September 1955 https://doi.org/10.1111/j.1699-0463.1955.tb00922.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume37, Issue1September 1955Pages 94-98 RelatedInformation

Local X-irradiation promotes regeneration of spinal cord central nervous system in a rat model

To evaluate the effect of local X-irradiation on spinal cord injury by using physiology, kinology, electrophysiology and histology method. 46 female Sprague-Dawley rats were subjected to spinal cord injury by weight dropping on T(11-12). All animals were divided into 3 groups randomly. One of the animal groups was irradiated with 10 Gy at the lesion site; another was irradiated with 20 Gy, the other without irradiation is regarded as sham-group. The animals were euthanized at different time points at 4 and 12 weeks after irradiation. Spinal cord callus was assessed by using physiology, kinology, and electrophysiology and histology method. In all the groups, the NF at 14 weeks were found higher than that of 6 weeks. Both 10 Gy irradiated and 20 Gy irradiated groups were higher than those of group at each time point (P < 0.05). The MBP decreased at 14 weeks in irradiated groups (P < 0.05), but increased at 14 weeks in sham-group (P < 0.05), the MBP of irradiated groups was lower than that sham-group at 14 weeks (P < 0.05). The GFAP and Nogo-A at 14 weeks were higher than that in 6 weeks in all the groups (P < 0.05), and there was no statistical significance with physiology, kinology, electrophysiology test in all groups. A self-repair mechanism exists after SCI, which will last at least 14 weeks. Local irradiation promotes the regeneration of spinal cord system after injury to some extent.

The effect of neonatal x-irradiation on the accumulation of (3H) by the central nervous system of the rat following injection of (3H)-5-uridine.

The effect of neonatal x-irradiation on the accumulation of (3H) by the central nervous system of the rat following injection of (3H)-5-uridine.

Study on inhibitory effect of low-dose X-irradiation on chronic alcohol-induced damage in mouse

Study on inhibitory effect of low-dose X-irradiation on chronic alcohol-induced damage in mouse

Histological study on inhibitory effects of low-dose X-irradiation on freezing-induced mouse brain damage

Histological study on inhibitory effects of low-dose X-irradiation on freezing-induced mouse brain damage

Induction of apoptosis by Drosophila Myc

Myc proteins are essential regulators of cellular growth and proliferation during normal development. Activating mutations in myc genes result in excessive growth and are frequently associated with human cancers. At the same time, forced expression of Myc sensitizes vertebrate cells towards different pro-apoptotic stimuli. Recently, the ability of overexpressed Myc to induce cell-autonomous apoptosis has been shown to be evolutionarily conserved in Drosophila Myc (dMyc). Here, we show that dMyc induced apoptosis is accompanied by the induction of Drosophila p53 mRNA, but that dp53 activity is not essential for dMyc's ability to induce apoptosis. Conversely, larvae carrying a hypomorphic dmyc mutation are more resistant to the apoptosis-promoting effects of X-irradiation. These data suggest that the control of apoptosis is a physiological function of Myc and that dMyc might play a role in the response to DNA damage.

Effect of X-irradiation on gene expression of rat liver chemokines: in vivo and in vitro studies

Effect of X-irradiation on gene expression of rat liver chemokines: in vivo and in vitro studies

Growth Cone Collapse and Neurite Retractions: An Approach to Examine X-irradiation Affects on Neuron Cells

The growth cone is a structure at the terminal of a neurite that plays an important role in the growth of the neurite. The growth cone collapse assay is considered to be a useful method to quantify the effects of various factors on nerve tissue. Here, we investigated the effect of x-irradiation on growth cones and neurites and also the comparative radiosensitivity of different neurons. Dorsal root ganglia and sympathetic chain ganglion were isolated from day-8 and -16 chick embryos and cultured for 20 h. Neurons were then exposed to x-irradiation and morphological changes were quantitatively evaluated by growth cone collapse assay. Cell viability was examined using TUNEL and WST-1 assays. The results showed that radiation induced growth cone collapse and neurite retraction in a time- and exposure-responsive manner. Growth cone collapse, apoptosis and WST-1 assays showed that no significant difference between the neurons throughout the study period (p > or = 0.5) after irradiation. Both types of day-8 neurons were more radio-sensitive than day-16 neurons (p < or = 0.05). The time course of the growth cone collapse was significantly correlated with the apoptotic and cell viability responses at different irradiation doses. Growth cone collapse may represent a useful marker for assaying the effect of x-irradiation on normal cell neurons.

Reversible effect of X‐irradiation on proliferation, neurogenesis, and cell death in the dentate gyrus of adult mice

Therapeutic cranial X-irradiation causes cognitive deficits in adult and pediatric patients, in particular, when the exposed area includes the medial temporal lobes. Effects on adult neurogenesis within the hippocampus may be related to such deficits. To investigate this relation, we irradiated the brain of young adult C57Bl/6j mice with a single dose of 4 Gy at a dose-rate of 27.5 cGy/min. We observed an approximately 80% decrease in the number of cells immunoreactive for the proliferation marker Ki67, 16 and 48 h after exposure, which was restored to control values after 1 week. The number of doublecortin- and NeuroD-immunoreactive cells of neuronal lineage was reduced by 60-70% up to 1 week after irradiation, but not after 1 month. The number of pyknotic cells increased approximately 2.5 fold after 16 h, decreased to approximately 50% of control numbers after 48 h and 1 week, and was again at normal levels after 1 month. Granule cell number did not differ between different groups and time points. There was no apparent activation of microglia or astrocytes. Our findings consist of an acute and reversible effect of X-irradiation on proliferation, neurogenesis, and cell death. Transient changes of neurogenesis may play a role in transient impairments of cognitive performance of patients exposed to X-irradiation. We present an experimental approach to temporarily alter adult hippocampal neurogenesis (AhN), allowing mechanistic investigations of AhN and its relevance to cognitive performances. The work also represents a step toward optimized radiotherapy schedules.

Indonesia

X-irradiation is a kind of immunosupression which dangerous for health. X-ray can disturb limfosit’s capability to cleavage then reduce the infection immune response. Decreasing immune response, caused by X-irradiation, can be shown in the decrease of antibodies production. The aims of this research were to know significant difference’s antibodies production among the doses of 0.0 Gy, 0.5 Gy, 1.5 Gy, and 3.0 Gy X-ray and the effect of X-irradiation on the BALB/c mice antibodies production after tetanus toxoid immunization. Mice were grouped into four groups with the treatments of 0.0 Gy dose, 0.5 Gy dose, 1.5 Gy dose, 3.0 Gy dose X-ray for 1st, 2nd, 3rd, and 4th group respectively. External irradiation was applied once on the whole body of mice. Tetanus toxoid immunization was done 24 hours after Xirradiation. Indirect ELISA was used to determine the presence of antibodies in serum samples as the quantitative data. Its were analyzed by one way ANOVA and regression. One way of ANOVA was done to know significant difference’s antibodies production among the doses of 0.0 Gy, 0.5 Gy, 1.5 Gy, and 3.0 Gy X-ray then continued with DMRT on 5% significant rate if there was any marked difference. Regression was done to know the effect of X-irradiation on the BALB/c mice antibodies production after tetanus toxoid immunization. Qualitative observations were done on poisoned symptom, the changes of physical and behavior, and mortality. The result of the research showed that there weren’t significant difference’s antibodies production with tetanus toxoid vaccine gift among the dose of 0.0 Gy, 0.5 Gy and 1.5 Gy as the same as 0.5 Gy, 1,5 Gy, and 3,0 Gy dose of X-ray. There was a significant difference at 3.0 Gy and 0.0 Gy dose of X-ray. X-irradiation influenced the antibodies production with tetanus toxoid vaccine gift by caused antibody rate degradation along with the increasing of X-ray dose.

The effect of prenatal X-irradiation on the developing cerebral cortex of rats. II: A quantitative assessment of glial cells in the somatosensory cortex

The developing central nervous system is known to be highly vulnerable to X-irradiation. Although glial cells are involved in various brain functions, knowledge on the effects of X-irradiation on glial cells is limited. Therefore, the purpose of the present study was to evaluate the effects of prenatal X-irradiation on glial cells. Pregnant Wistar rats were exposed to X-irradiation at a dose of 1.0Gy on day 15 of gestation. Their offspring were examined at 7 weeks of age. The forebrain weight of X-irradiated rats was significantly lower than that of the age-matched controls. Histological quantification with stereology of the somatosensory cortex (SC) revealed no significant difference in the numerical density of glial cells between the X-irradiated and control rats. However, the glial cells in the X-irradiated animals had significantly larger nuclear size. We had previously reported that a similar X-irradiation paradigm resulted in no significant change in the numerical density of neurons in the SC. According to the results of the present study, there were no significant differences in the glial cell-to-neuron ratios between the X-irradiated and control animals. Taken together, it is speculated that prenatal X-irradiation has an equal effects on the numerical densities of glial cells and neurons.

Therapeutic Effect of pEgr-IL18-B7.2 Gene Radiotherapy in B16 Melanoma-Bearing Mice

To evaluate the antitumor role of genes B7.2 and IL18, the radiation-inducible dual-gene coexpression plasmid pEgr-IL18-B7.2 was constructed and its effects on tumor were detected both in vitro and in vivo. After the introduction of pEgr-IL18-B7.2 into B16 melanoma cells, followed by X-ray irradiation, higher expression levels of B7.2 and IL18 compared with control were found both by flow cytometry and enzyme-linked immunosorbent assay. It was shown that even low-dose irradiation was able to induce their expression, which could be tightly regulated either by giving cells different doses of radiation or the same dose at different time points. pEgr-IL18-B7.2 was then packaged with liposome and injected into melanoma tumor-bearing mice. The tumors received 5 Gy of local X-ray irradiation every other day for a total of five treatments. B16 tumor growth slowed significantly when treated with pEgr-IL18-B7.2 plus X-radiation versus either treatment separately. Both 1 and 3 days after the last irradiation the group of mice with combined gene and radiation therapy showed significantly higher tumor necrosis factor (TNF)-alpha secretion in peritoneal macrophages, upregulated splenic cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, and higher interferon (IFN)-gamma secretion than those in either individual treatment group or the control group. The stimulation of host anticancer immunity by increased secretion of IL-18 and upregulated immunogenicity of the tumor cells by increased expression of B7.2 on their surface, in addition to the direct effect of local X-irradiation on the tumor cells, may contribute to the novel effect of the combined therapy.

Point:Counterpoint: Satellite cell addition is/is not obligatory for skeletal muscle hypertrophy

Myofiber size is dynamically regulated, increasing and decreasing depending on muscle use. Hypertrophy is defined by increases in myofiber cross-sectional area and mass as well as myofibrillar protein content. Myofibers contain many hundreds of nuclei, each of which has a nuclear domain. A nuclear

A different regional response by mouse oligodendrocyte progenitor cells (OPCs) to high‐dose X‐irradiation has consequences for repopulating OPC‐depleted normal tissue

This study was designed to investigate whether the residual, dysfunctional oligodendrocyte progenitor cells (OPCs) observed following X-irradiation of the mouse spinal cord [D. M. Chari et al. (2003) Exp. Neurol., 198, 145-153], the presence of which prevented the endogenous repopulation of these areas from normal tissue, reflects a general response of OPCs in the mouse central nervous system (CNS) to X-irradiation. The brains of adult mice were exposed to 40 Gy of X-irradiation and the effect of X-irradiation on the OPCs was assessed up to 4 weeks post-irradiation using anti-NG2 antibodies. X-irradiation resulted in almost complete depletion of OPCs within the telencephalon (cortex, corpus callosum and hippocampus) by 7 days post-irradiation, which was followed by progressive repopulation of OPCs from non-irradiated areas of the cortex. By contrast, within the lower brain centres (the diencephalon and mesencephalon) OPC loss occurred much more slowly so that 26% of the OPCs still remained 4 weeks after X-irradiation. The consequence of this heterogeneous response to X-irradiation was that whereas transplanted and endogenous OPCs rapidly established themselves in the OPC-depleted telencephalon this did not occur in the areas where there was incomplete depletion of endogenous OPCs. Our findings confirm not only the requirement for almost complete OPC depletion in order to establish transplanted OPCs in normal tissue but also highlight a heterogeneity of progenitor populations in different areas of the mouse CNS.

The synergistic effect of dimethylamino benzoylphenylurea (NSC #639829) and X-irradiation on human lung carcinoma cell lines

The present study was designed to investigate the ability of N-[4-(5-bromo-2-pyrimidyloxy)-3-methylphenyl]-(dimemethylamino)-benzoylphenylurea (dimemethylamino benzoylphenylurea; BPU) to sensitize cells to radiation and to examine the relationship between phenotype versus survival, DNA damage, apoptosis, or cell cycle progression in non-small cell lung cancer (NSCLC) cell lines. Asynchronous cultures of three NSCLC (phenotype) lines, A549 (adenocarcinoma), NCI-H226 (squamous) and NCI-H596 (adenosquamous) were used. Cells were treated for 24 h with BPU at various concentrations (0-10 microM) to obtain drug doses for inhibiting cell survival by approximately 50% (IC50). Cells were X-irradiated without BPU or after 24 h BPU treatment at IC50. Radiation doses ranged from 0 to10 Gy. Cell survival was determined by a colony-forming ability assay. The effect of BPU on the cell cycle distribution and induction of apoptosis were measured by flow cytometry-based assays. The effect of BPU on radiation-induced DNA damage and repair was analyzed according to nuclear gammaH2AX immunofluorescence of cells exposed to X-rays alone or after BPU. Anti-gammaH2AX antibody staining, a surrogate determinant of double stranded DNA breaks, was measured using flow cytometry. BPU (1.5 microM) for 24 h produced approximately 50% cell survival. BPU and X-irradiation were synergistic in the three cell lines at survival levels of 20-50%. Flow cytometry analysis of replicate experiments with BPU (1.5 microM for 24 h) showed that BPU blocked cell progression at S and/or G2/M. The incidence of apoptosis in BPU-treated versus control cells ranged from approximately 0.3 to approximately 8%. Twenty-four hour after X-irradiation cells pre-treated with BPU and X-irradiated after drug exposure showed gammaH2AX levels approximately two times higher than did the cells exposed to X-rays only. The study identified BPU as a novel radiation sensitizer. The analysis of phosphorylated histone H2AX as a surrogate marker of DNA double strand breaks suggested a positive association between radiosensitization and the inhibition of X-irradiation-induced DNA damage repair by BPU.

Mutagenesis effects of X-irradiation on the germination, growth and development of Maize (&lt;I&gt;Zea mays&lt;/I&gt;) seeds due to time of exposure (part 1)

The time of exposure and mutagenesis effects of X-ray on the germination, growth and development of maize ( Zea mays ) seeds have been investigated employing a nuclear source, ( 90 Sr as X-ray source; 3mA, 70kv). Five sects of zea mays seeds in different packs were irradiated in different times of exposure and later planted separately with another 6 th non-irradiated sects (control experiment) on an open fertile land. Measurements at eight days interval were carried out on the plants' heights, its leaves widths, days to anther and silk for six consecutive times after planting. Results revealed, the day to anther (42) days and day to silk (35) days after planting respectively for the irradiated sects were delayed. A comparative study carried out on all the sects in terms of the plants' height and leaves' width indicated that 83 percent of the plants examined showing consistent mutation in both heights and leaves width as a function of time of exposure. Global Journal of Pure and Applied Sciences Vol. 12(2) 2006: 221-224

How to Avoid Premature Decay of Your Macromolecular Crystal: A Quick Soak for Long Life

Radiation damage to biological samples is currently one of the major limiting factors in macromolecular X-ray crystallography, since it severely and irreversibly affects the quality of the data that can be obtained from a diffraction experiment. However, radiation damage can effectively be reduced by utilizing the electron and radical scavenging potential of certain small-molecule compounds. We propose an approach to protect macromolecular crystals prior to data collection by quick soaking with scavengers. This, in favorable cases, can more than double crystal lifetime in the X-ray beam. The approach has the potential to yield diffraction data of superior quality and hence to increase the amount of high-quality diffraction data and of structural information attainable from a single crystal.