Killing of Aspergillus fumigatus by alveolar macrophages is mediated by reactive oxidant intermediates

Phagocytosis and mechanisms of killing of Aspergillus fumigatus conidia by murine alveolar macrophages (AM), which are the main phagocytic cells of the innate immunity of the lung, were investigated. Engulfment of conidia by murine AM lasts 2 h. Killing of A. fumigatus conidia by AM begins after 6 h of phagocytosis. Swelling of the conidia inside the AM is a prerequisite for killing of conidia. The contributions of NADPH oxidase and inducible nitric oxide synthase to the conidicidal activity of AM were studied using AM from OF1, wild-type and congenic p47phox(-/-) 129Sv, and wild-type and congenic iNOS(-/-) C57BL/6 mice. AM from p47phox(-/-) mice were unable to kill A. fumigatus conidia. Inhibitors of NADPH oxidase that decreased the production of reactive oxidant intermediates inhibited the killing of A. fumigatus without altering the phagocytosis rate. In contrast to NADPH oxidase, nitric oxide synthase does not play a role in killing of conidia. Corticosteroids did not alter the internalization of conidia by AM but did inhibit the production of reactive oxidant intermediates and the killing of A. fumigatus conidia by AM. Impairment of production of reactive oxidant intermediates by corticosteroids is responsible for the development of invasive aspergillosis in immunosuppressed mice.

Thrombopoietin promotes hematopoietic recovery and survival after high-dose whole body irradiation

PURPOSE

The therapeutic potential of thrombopoietin (TPO), the major regulator of platelet production, was evaluated for hematopoietic recovery and survival in mice following lethal and supralethal total body irradiation (TBI).

METHODS AND MATERIALS

Hematopoietic recovery was studied in C57BL6/J mice after 8 Gy TBI (gamma-rays). Survival experiments were performed with C57BL6/J and BCBA F1 mice. Two protocols of TPO administration were evaluated: treatment for 7 consecutive days (7 x 0.3 microg/mice) beginning 2 h after exposure, or a single dose (0.3 microg/mice) administered 2 h after irradiation.

RESULTS

TPO improved the platelet nadir and accelerated the platelet reconstitution of irradiated mice in comparison to placebo-treated mice. Recovery of neutrophils and erythrocytes was stimulated as well. TPO induced an accelerated recovery of hematopoietic progenitors and immature multilineage progenitors in bone marrow and spleen. In addition, TPO administration induced approximately 90% survival of 8 Gy irradiated C57BL6/J mice, a TBI dose which resulted in 100% mortality within 30 days for placebo-treated mice. Single TPO administration was as effective as repeated injections for hematopoietic recovery and prevention of mortality. Dose-effect survival experiments were performed in BCBA F1 mice and demonstrated that TPO shifted the LD50/30 from approximately 9.5 Gy to 10.5 Gy TBI given as a single dose, and from 14 Gy to as high as 17 Gy when TBI was given in three equal doses, each separated by 24 h.

CONCLUSION

These results demonstrate that the multilineage hematopoietic effects of TPO may be advantageously used to protect against lethal bone marrow failure following high dose TBI.

Abdominal radiation exposure elicits inflammatory responses and abscopal effects in the lungs of mice

An inflammatory reaction is a classical feature of radiation exposure and appears to be a key event in the development of the acute radiation syndrome. We have investigated the radiation-induced inflammatory response in C57BL6/J mice after total abdominal or total-body irradiation at a dose of 15 Gy. Our goal was to determine the radiation-induced inflammatory response of the gut and to study the consequences of abdominal irradiation for the intestine and for the lungs as a distant organ. A comparison with total-body irradiation was used to take into account the hematopoietic response in the inflammatory process. For both irradiation regimens, systemic and intestinal responses were evaluated. A systemic inflammatory reaction was found after abdominal and total-body irradiation, concomitant with increased cytokine and chemokine production in the jejunum of irradiated mice. In the lungs, the radiation-induced changes in the production of cytokines and chemokines and in the expression of adhesion molecules after both abdominal and total-body irradiation indicate a possible abscopal effect of radiation in our model. The effects observed in the lungs after irradiation of the abdomino-pelvic region may be caused by circulating inflammatory mediators consequent to the gut inflammatory response.

Characterization of the response of human bone marrow endothelial cells to in vitro irradiation

Endothelial cell dysfunction is a classic consequence of radiation damage. Bone marrow endothelial cells (BMEC) are a critical component of the stroma in the regulation of haemopoiesis. In animal models, radiation-induced injury of BMEC has been described and a role for BMEC in haemopoietic regeneration after irradiation has been suggested. However, functions of BMEC involved in the haemopoietic regeneration have not been assessed. Therefore we studied the functional response of human BMEC to irradiation using the transformed human BMEC line (TrHBMEC) irradiated with 2. 5 or 10Gy. Our results showed a time- and a dose-dependent increase in damage to irradiated TrHBMEC measured by a decreased number of adherent cells which correlated with increased apoptosis and augmented release of soluble ICAM-1 and von Willebrand factor. 2 Gy irradiated TrHBMEC expressed more ICAM-1 on their surface than non-irradiated cells, whereas no change in VCAM-1, E-selectin and PECAM-1 expression was observed. An increased production of G-CSF, GM-CSF, IL-8, IL-6, IL-1alpha, IL-11, MIP-1alpha and SCF and no production of LIF, TNF-alpha, TPO and IL-3 by 2 Gy irradiated TrHBMEC was observed. The haemopoietic supportive function of TrHBMEC was not altered after a 2 Gy exposure. These results suggest that although radiation induces endothelial cell damage, irradiated cells still support the proliferation and the differentiation of CD34+ haemopoietic cells.

Characterization of the acute inflammatory response after irradiation in mice and its regulation by interleukin 4 (Il4)

The aim of this study was to determine the effects of total-body irradiation of mice on the acute release of a panel of several mediators of inflammation and to evaluate the efficacy of Il4 in regulating these radiation-induced modifications. We studied the effects of exposure of C57BL6/J mice to 8 Gy gamma rays on the early release of cytokines, chemokines, acute-phase proteins, prostaglandins and corticosterone in either plasma or tissues compared to those observed after intraperitoneal injection of lipopolysaccharide from 1 h to 3 days after stimulation. During the characterization of the acute inflammatory response induced by radiation or lipopolysaccharide, we observed differences both in the type of mediators produced and in the time course of release. We next determined the anti-inflammatory potential of Il4 in this model of total-body irradiation. We found that Il4 was able to down-regulate the radiation-induced production of mediators of inflammation such as Gro1 (also known as KC, N51) in plasma and lung, corticosterone in blood, Il1b in lung, and prostaglandin E(2) in colon, suggesting the anti-inflammatory potential of Il4 in regulating the radiation-induced response.

Single administration of thrombopoietin to lethally irradiated mice prevents infectious and thrombotic events leading to mortality

A sufficiently high dose of thrombopoietin to overcome initial c-mpl-mediated clearance stimulates hematopoietic reconstitution following myelosuppressive treatment. We studied the efficacy of thrombopoietin on survival after supralethal total body irradiation (9 Gy) of C57BL6/J mice and the occurrence of infectious and thrombotic complications in comparison with a bone marrow graft or prophylactic antibiotic treatment. Administration of 0.3 microg thrombopoietin, 2 hours after irradiation, protected 62% of the mice as opposed to no survival in placebo controls. A graft with a supraoptimal number of syngeneic bone marrow cells (10(6) cells) fully prevented mortality, whereas antibiotic treatment was ineffective. Blood cell recovery was observed in the thrombopoietin-treated mice but not in the placebo or antibiotic-treated group. Bone marrow and spleen cellularity as well as colony-forming unit granulocyte-macrophage and burst-forming unit erythroid were considerably increased in thrombopoietin-treated mice relative to controls. Histologic examination at day 11 revealed numerous petechiae and vascular obstructions within the brain microvasculature of placebo-treated mice, which was correlated with hypercoagulation and hypofibrinolysis. Thrombopoietin treatment prevented coagulation/fibrinolysis disorder and vascular thrombosis. High fibrinogen levels were related to bacterial infections in 67% of placebo-treated mice and predicted mortality, whereas the majority of the thrombopoietin-treated mice did not show high fibrinogen levels and endotoxin was not detectable in plasma. We conclude that thrombopoietin administration prevents mortality in mice subjected to 9-Gy total body irradiation both by interfering in the cascade leading to thrombotic complications and by amelioration of neutrophil and platelet recovery and thus protects against infections and hemorrhages.

Tumorigenic conversion of human mesothelial cells as a consequence of platelet-derived growth factor-A chain overexpression

Overexpression of platelet-derived growth factor (PDGF)-A as well as PDGF-B chain mRNA has previously been reported in human mesothelioma cell lines. In this report, it has been established that the A but not the B chain protein is expressed at detectable levels in cell lysates and conditioned medium from these cell lines. In order to investigate the effect of overexpression of PDGF-A chain in a human mesothelial cell model system, a retroviral vector containing a human PDGF-A chain cDNA insert under the control of the Moloney murine leukemia virus (MoMLV) promoter was inserted into the SV-40 T-antigen immortalized human mesothelial cell line MeT-5A. Selected cells showed overexpression of PDGF-A chain relative to MeT-5A and induced tumors in athymic nude mice. PDGF-A chain overexpression was also found in the tumor specimens excised from the mice. PDGF-A mRNA and protein were expressed at a higher level in the tumor explant cell lines, suggesting a correlation of tumorigenicity with A chain production.

Mesothelioma in rats following intrapleural injection of chrysotile and phosphorylated chrysotile (chrysophosphate)

Pathological effects of asbestos are probably dependent on the size and surface properties of the fibers. Surface-modified chrysotile fibers were injected into the pleural cavity of rats to investigate the potency of the fiber to induce mesothelioma. Chrysotile fibers were modified by a phosphorylation process, resulting in the presence of phosphorus at the fiber surface. Phosphorylated samples were characterized by enhanced durability and reduced affinity for biological macromolecules. Five samples were tested: 1 untreated and 4 phosphorylated. ChrP1, ChrP2 and ChrP3 corresponded to phosphorylated samples obtained by first, second and third passages through an Alpine classifier; Pm was defibrillated ChrP1. The number of fibers per microgram and the size distribution were determined by transmission electron microscopy and classified in 4 size groups. Groups of 35 rats were inoculated with 20 mg of fibers suspended in 0.9% NaCl solution. No mesothelioma was found in the saline controls. All fiber samples were proficient in producing mesothelioma; the percentages were different between groups and untreated chrysotile but not significantly so. The differences may be explained on the basis of the number of fibers injected which were greater than 8 microns in length and less than 0.25 microns in diameter. The findings of a proficiency of long fibers to produce mesothelioma, previously reported by others for glass fibers, could be applied to chrysotile.

Internal contamination by actinides after wounding: a robust rodent model for assessment of local and distant actinide retention

Internal contamination by actinides following wounding may occur in nuclear fuel industry workers or subsequent to terrorist activities, causing dissemination of radioactive elements. Contamination by alpha particle emitting actinides can result in pathological effects, either local or distant from the site of entry. The objective of the present study was to develop a robust experimental approach in the rat for short- and long- term actinide contamination following wounding by incision of the skin and muscles of the hind limb. Anesthetized rats were contaminated with Mixed OXide (MOX, uranium, plutonium oxides containing 7.1% plutonium) or plutonium nitrate (Pu nitrate) following wounding by deep incision of the hind leg. Actinide excretion and tissue levels were measured as well as histological changes from 2 h to 3 mo. Humid swabs were used for rapid evaluation of contamination levels and proved to be an initial guide for contamination levels. Although the activity transferred from wound to blood is higher after contamination with a moderately soluble form of plutonium (nitrate), at 7 d most of the MOX (98%) or Pu nitrate (87%) was retained at the wound site. Rapid actinide retention in liver and bone was observed within 24 h, which increased up to 3 mo. After MOX contamination, a more rapid initial urinary excretion of americium was observed compared with plutonium. At 3 mo, around 95% of activity remained at the wound site, and excretion of Pu and Am was extremely low. This experimental approach could be applied to other situations involving contamination following wounding including rupture of the dermal, vascular, and muscle barriers.

Human mesothelioma cells and asbestos-exposed mesothelial cells are selectively resistant to amosite toxicity: a possible mechanism for tumor promotion by asbestos

To determine if asbestos exposure could contribute to mesothelial cell carcinogenesis by selection and/or expansion of an initiated cell population, we compared normal human pleural mesothelial cells to either human mesothelioma cell lines or mesothelial cells transfected with cancer-related genes for sensitivity to amosite fibers in vitro. Neither normal nor mesothelioma cells were directly stimulated to replicate or increase DNA synthesis by any of the asbestos exposure conditions tested. The potential selective effect of asbestos exposure was demonstrated by a differential sensitivity of normal mesothelial cells and mesothelioma cells to amosite: for example, up to 20-fold higher concentrations of amosite fibers were required to inhibit replication of mesothelioma cell lines than normal mesothelial cells. In addition, a significant resistance (4-fold) to amosite toxicity was observed for SV40 immortalized mesothelial cell lines that had previously been selected in vitro for resistance to asbestos. SV40 immortalized cells that have become tumorigenic after transfection with either Ha-ras or PDGF A-chain genes were not significantly more resistant to the cytotoxic effects of amosite than primary normal cells, and the primary cells were equally sensitive to amosite as mesothelial cells that were only immortalized by SV40. The sensitivity of normal mesothelial cells to asbestos does not appear to be simply a result of general fragility of the mesothelial cells, since similar levels of hydrogen peroxide and silica were cytotoxic for normal mesothelial cells and mesothelioma cell lines. Because mesothelioma cells have a greater resistance to asbestos cytotoxicity than normal mesothelial cells, we hypothesize that a differential resistance to cell killing by asbestos fibers in vivo may result in a selective expansion of an initiated or transformed cell population and thus contribute to the carcinogenesis process. Since tumorigenicity and asbestos resistance occur independently of one another in genetically altered mesothelial cell lines, genotypic and phenotypic alterations that lead to tumorigenic conversion may not be the same changes that provide resistance to cell killing by asbestos.

Isotopic and elemental composition of plutonium/americium oxides influence pulmonary and extra-pulmonary distribution after inhalation in rats

The biodistribution of plutonium and americium has been studied in a rat model after inhalation of two PuO(2) powders in lungs and extra-pulmonary organs from 3 d to 3 mo. The main difference between the two powders was the content of americium (approximately 46% and 4.5% of total alpha activity). The PuO(2) with a higher proportion of americium shows an accelerated transfer of activity from lungs to blood as compared to PuO(2) with the lower americium content, illustrated by increased urinary excretion and higher bone and liver actinide retention. The total alpha activity measured reflects mostly the americium biological behavior. The activity contained in epithelial lining fluid, recovered in the acellular phase of broncho-alveolar lavages, mainly contains americium, whereas plutonium remains trapped in macrophages. Epithelial lining fluid could represent a transitional pulmonary compartment prior to translocation of actinides to the blood and subsequent deposition in extra-pulmonary retention organs. In addition, differential behaviors of plutonium and americium are also observed between the PuO(2) powders with a higher dissolution rate for both plutonium and americium being obtained for the PuO(2) with the highest americium content. Our results indicate that the biological behavior of plutonium and americium after translocation into blood differ two-fold: (1) for the two actinides for the same PuO(2) aerosol, and (2) for the same actinide from the two different aerosols. These results highlight the importance of considering the specific behavior of each contaminant after accidental pulmonary intake when assessing extra-pulmonary deposits from the level of activity excreted in urine or for therapeutic strategy decisions.

Growth of normal and neoplastic rat pleural mesothelial cells in the presence of conditioned medium from neoplastic mesothelial cells

Several transformed cells have been demonstrated to secrete growth factors. We studied the effect of conditioned medium from neoplastic rat pleural mesothelial cells on normal and neoplastic mesothelial cell growth. The results showed that the concentrated conditioned medium stimulated neoplastic mesothelial cell growth but inhibited reversibly normal mesothelial cell growth.

In vitro growth characteristics of rat mesothelioma cells in culture

The study reports morphological growth characteristics and chromosome analysis of neoplastic rat pleural mesothelial cells (RPMC) isolated from a mesothelioma-bearing rat. The pleural mesothelioma was induced by intrapleural injection of chrysotile fibers. Neoplastic RPMC were cultured by the standard methods used for normal RPMC. Neoplastic RPMC cultures had a population doubling time of 19 hr versus 30 hr for the normal cells. Plating efficiency in liquid medium was almost 100%. Cultures of neoplastic RPMC were anchorage-independent since 70% of the seeded cells formed colonies after one week; after the second week, colony size was enhanced but colony recovery was not. The serum dependence of neoplastic cells was less than that of the normal cells. 79 out of 100 metaphase cells analyzed had 41 to 43 chromosomes, and the modal number was 42 (38%). A large metacentric chromosome was observed in 77 of the 100 neoplastic metaphase cells analyzed, but not in any normal metaphase cells. In nude mice, the neoplastic RPMC were tumorigenic.

Effect of epidermal growth factor on rat pleural mesothelial cell growth

We recently reported that the growth of normal rat pleural mesothelial cells (RPMCs) is inhibited by conditioned media from either in vivo or in vitro transformed RPMCs. In this study we report that the growth of normal RPMCs is inhibited by epidermal growth factor (EGF). This was demonstrated by using three methods of investigation. Two types of studies were carried out with growing cells. First, cell counts indicated that the number of cells was reduced in EGF-treated cultures when compared with untreated cultures. Second, the percentage of S cells detected by flow cytometry following treatment with EGF was lower than without EGF. In other experiments, incorporation of tritiated thymidine in confluent cells was decreased by EGF treatment, either in the presence or absence of fetal calf serum; these effects were dose dependent and were observed from 2 ng/ml EGF. Lower EGF concentrations did not significantly modify thymidine incorporation when compared with untreated cells. Analysis of 125I EGF binding experiments by the Scatchard method indicated that RPMCs posses EGF receptors (about 10(5) per cell) with low ligand binding affinity (Kd = 1.7 +/- 0.4 nM). These results indicate that EGF might modulate the growth of RPMCs.

Late-occurring pulmonary pathologies following inhalation of mixed oxide (uranium + plutonium oxide) aerosol in the rat

Accidental exposure by inhalation to alpha-emitting particles from mixed oxide (MOX: uranium and plutonium oxide) fuels is a potential long-term health risk to workers in nuclear fuel fabrication plants. For MOX fuels, the risk of lung cancer development may be different from that assigned to individual components (plutonium, uranium) given different physico-chemical characteristics. The objective of this study was to investigate late effects in rat lungs following inhalation of MOX aerosols of similar particle size containing 2.5 or 7.1% plutonium. Conscious rats were exposed to MOX aerosols and kept for their entire lifespan. Different initial lung burdens (ILBs) were obtained using different amounts of MOX. Lung total alpha activity was determined by external counting and at autopsy for total lung dose calculation. Fixed lung tissue was used for anatomopathological, autoradiographical, and immunohistochemical analyses. Inhalation of MOX at ILBs ranging from 1-20 kBq resulted in lung pathologies (90% of rats) including fibrosis (70%) and malignant lung tumors (45%). High ILBs (4-20 kBq) resulted in reduced survival time (N = 102; p < 0.05) frequently associated with lung fibrosis. Malignant tumor incidence increased linearly with dose (up to 60 Gy) with a risk of 1-1.6% Gy for MOX, similar to results for industrial plutonium oxide alone (1.9% Gy). Staining with antibodies against Surfactant Protein-C, Thyroid Transcription Factor-1, or Oct-4 showed differential labeling of tumor types. In conclusion, late effects following MOX inhalation result in similar risk for development of lung tumors as compared with industrial plutonium oxide.

Forecasting the In Vivo Behavior of Radiocontaminants of Unknown Physicochemical Properties Using a Simple In Vitro Test

An understanding of the "bioavailability" of disseminated radiocontaminants is a necessary adjunct in order to tailor treatment and to calculate dose. A simple test has been designed to predict the bioavailability of different actinide forms likely to be found after dissemination of radioactive elements by dispersal devices or nuclear reactor incidents. Plutonium (Pu) or Americium (Am) nitrate or MOX (U,PuO2) are immobilized in culture wells using a static gel phase simulating biological compartments (lung, wound, etc.). Gels are incubated in a fluid phase representing physiological media (plasma, sweat, etc.). Transfer of radionuclide from static to fluid phase reflects contaminant bioavailability. After 48 h of incubation in physiological saline, Am transfer from static to fluid phase was greater than for Pu (70% vs. 15% of initial activity). Transfer of Pu or Am was markedly less from the oxide form of the two elements (1% Am and 0.05% Pu transferred). Medium representing intracellular lysosomal fluid (pH 4) increased transfer of Pu and Am, whereas culture medium including serum reduced actinide transfer. Actinide transfer was also reduced by elements of the extracellular matrix present in the static gel phase. Increasing DTPA concentrations (5 to 500 μM) to the fluid phase significantly enhanced transfer of Pu and Am. Although this agarose gel cannot fully represent in vivo complexity, this simple test can be used to investigate and predict the behavior in vivo of radiocontaminants to support medical treatments and medical forensic investigations.

Evidence for a differential translocation of actinides across human lung epithelial cell monolayer in vitro according to their physicochemical properties and the presence of a chelating agent

The epithelial cell plays a key role in the transfer of radionuclides from lungs to blood following pulmonary exposure. The present study was designed to evaluate the transfer across human lung epithelial cells of various actinides (plutonium, americium and uranium), the influence of the physicochemical properties of plutonium compounds and of the chelating agent diethylene triamine pentaacetic acid (DTPA). To address this question, Calu-3 cells grown in a bicameral culture system were used. The integrity of the epithelial barrier was evaluated by measuring transepithelial electrical resistance (TEER) and the passage of a fluorescent marker, lucifer yellow. Activity measurement in basal compartment following periodic collection of culture medium was made from 2 h to seven days. To facilitate data handling and analysis, the statistical tool STATBIODIS was used. The results indicate differences in transfer for the different elements, and according to Pu physicochemical properties. Though to various extents, the chelating agent DTPA always increased the transfer of Pu and Am across the epithelial cells, without altering the integrity of the epithelial barrier. This in vitro cell culture model, by mimicking translocation of actinides from lungs to blood, can represent a valuable tool to further understand the underlying mechanisms and properties controlling this process.

Influence of initial lung deposit on pulmonary clearance after plutonium oxide inhalation in rat

Alveolar macrophages are a key element in the clearance of inhaled particles after phagocytosis, and thus participate actively in lung dose distribution and in the risk of tumour formation. We studied the influence of initial lung deposit (ILD) on lung clearance and distribution of activity from 3 d to 3 months after inhalation of two forms of PuO2 (97% 239Pu and 70% 239Pu) in rats. ILDs ranging from 2.1 to 17 kBq were used. The total activity measured using X-ray spectrometry 3 months post-inhalation, relative to the ILD, showed a similar decrease in all groups, with the remaining activity representing approximately 30% of the ILD. The total activity recovered in bronchoalveolar lavages represented approximately 60% of the total lung activity. This ratio remained stable over time for the lowest ILD tested but decreased for higher ILD. In addition, the percentage of macrophages associated with particles decreased faster with time in rats with the highest ILD. Under our experimental conditions, there were no marked differences in lung clearance between groups. However, the distribution of the activity seems to vary with the time post-exposure between low and high ILD.

Interleukin 4 promotes survival of lethally irradiated mice in the absence of hematopoietic efficacy

The therapeutic potential of Il4 in lethally irradiated mice was evaluated in C57BL6/J mice subjected to 7 to 10 Gy total-body irradiation (TBI) from a (60)Co gamma-ray source. Il4 was administered 2 h after TBI either in a single injection or for 5 consecutive days. Il4 treatment increased 30-day survival of mice irradiated with doses as high as 8.5 Gy, which caused 100% mortality in placebo-treated animals. By convention, hematopoietic failure would induce death over a period of up to 30 days. However, in our study, the Il4-enhanced survival of mice within this period could not be attributed to significantly accelerated hematopoietic reconstitution as shown by blood cell counts and progenitor cell contents in the bone marrow and spleen. Our data strongly suggest that aplasia is not the only cause of death of animals irradiated with doses around the LD(50) and that Il4-treated animals can survive in spite of a very poor hematopoietic activity.

Behavioural consequences of an 8 Gy total body irradiation in mice: regulation by interleukin-4

The effects of an 8 Gy gamma total body irradiation (TBI) on exploration and locomotion activities as well as temperature were studied in C57BL6/J mice. Survival, body weight, and blood cell counts were also assessed in irradiated mice treated with placebo or interleukin (IL)-4. The efficacy of IL-4 treatment on improvement in exploration activity was evaluated. The study was carried out from 3 h to 30 days following exposure. Our results showed a biphasic response to irradiation concerning the exploration activity of mice. Irradiated mice had reduced activity as early as 3 h after exposure, with recovery of activity within 24 h. The exploration activity again decreased 4 days after irradiation and the recovery occurred slowly after day 17. IL-4 ameliorated the exploration status in mice in both phases. The locomotion activity was studied using a telemetry apparatus. A similar pattern to that of the exploration data was observed, with a minimal activity observed between days 13 and 17. A radiation-induced hypothermia was also noticed over the same time period.

[Therapeutic approaches of hematopoietic syndrome following accidental total whole body irradiation]

Since the first radiation accidents which resulted in severe health effects in the workforce or the population, great progress has been made in the fields of diagnosis, prognosis and treatment of accidentally overexposed victims. Since then, progress has also been made in the medical management of diseases such as aplasia. Because of the relative scarcity of radiation accidents, there is a need for complementary researches, in order to take advantage of new techniques and medical approaches. After whole body overexposure, the key issue is the therapeutic decision, ie, the choice between bone marrow transplantation and other strategies. The indications of bone marrow transplantation cover only a short range of doses, provided the exposure is distributed uniformly within the body. The last accidental overexposures which happened in the world have demonstrated the possible efficiency of haematopoietic growth factors, most of them being still under clinical trials. Actions based on these various approaches are summarized, as well as the lessons which have been learned.

Take a Swipe at Actinide Bioavailability: Application of a New In Vitro Method

ABSTRACT

Filter swipe tests are used for routine analyses of actinides in nuclear industrial, research, and weapon facilities as well as following accidental release. Actinide physicochemical properties will determine in part bioavailability and internal contamination levels. The aim of this work was to develop and validate a new approach to predict actinide bioavailability recovered by filter swipe tests. As proof of concept and to simulate a routine or an accidental situation, filter swipes were obtained from a nuclear research facility glove box. A recently-developed biomimetic assay for prediction of actinide bioavailability was adapted for bioavailability measurements using material obtained from these filter swipes. In addition, the efficacy of the clinically-used chelator, diethylenetriamine pentaacetate (Ca-DTPA), to enhance transportability was determined. This report shows that it is possible to evaluate physicochemical properties and to predict bioavailability of filter swipe-associated actinides.