Massive Irradiation Research Articles

Precession Electron Diffraction – a versatile tool for the characterization of Phase Change Materials

AbstractPrecession Electron Diffraction (PED) has become a versatile tool of Transmission Electron Microscopy (TEM) for enhancing its nanoscale characterization abilities. In this contribution the advantages of PED are demonstrated on bulk samples of Phase Change Materials (PCM) with the nominal compositions Ge8Sb2Te11 and Ge8Bi2Te11. PED was applied in combination with High Resolution Transmission Electron Microscopy (HRTEM) to determine such homologous structures based on variable sequences of layered building units. The efficiency of PED can be shown by the identification of ordering which is not evident from the projection of the structure in HRTEM or by use of Selected Area Electron Diffraction (SAED). Simulations support the ability of PED for recording 3D structural information. The PED patterns of the PCM can be assigned to superstructures which exhibit specific distances between adjacent Te‐Te double layers. PED was also performed to analyze the structural changes after massive irradiation of PCM crystals. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

THE ROLE OF THE EUROPEAN HAEMATOLOGIST IN A LARGE IRRADIATION EMERGENCY: THE EUROPEAN BLOOD AND MARROW TRANSPLANTATION SOCIETY (EBMT) NUCLEAR ACCIDENT COMMITTEE (NAC)

The European Blood and Marrow Transplantation Society's Nuclear Accident Committee has been a catalyst in bringing together consensus on the triage, Service Configuration, and care that might effectively be given by haematologists in the event of a massive irradiation incident. Further coordinated and integrated effort will be needed at European, international, and national levels to allow unified guidelines to treat such patients. The role of the training haematologist and devising a European Network of effective Service Configuration is the key to delivering an effective response if a major incident occurred.

Gamma and neutron massive irradiation tests of the ATLAS MDT chambers

MDT chambers, the precision tracking system of the ATLAS muon spectrometer, have to operate for 10 years in the harsh LHC background environment mainly due to low energy photons and neutrons. The expected overall maximum count rate is 500 Hz / cm 2 . Moreover the upgrades for S-LHC will involve fluxes ten times higher than that at LHC. To study the behavior of MDT chambers under massive irradiation of gammas and neutrons at level of S-LHC, three extensive tests were performed at the ENEA-Casaccia Research Centre Facilities, irradiating several test detectors. The results about the drift properties, gas gain and tracking performances, both at high rates and after massive irradiation, are given.

Adult Stem Cell Plasticity Defined

After completing this article, readers should be able to: 1. Define stem cell characteristics and the three separate classes of stem cells. 2. Define stem cell plasticity. 3. Describe four possible mechanisms of stem cell plasticity. 4. Describe clinical situations that may benefit from stem cell therapy. 5. Delineate areas of research that are needed to make feasible the use of adult stem cells for clinical therapy Investigators have postulated since the turn of the century that some cells in the body appear to participate in the formation of new cells to replace injured, aged, or infected cells in tissues and organs. The concept that certain specialized cells within an organ (stem cells) could give rise to mature functioning cells in that same organ has been demonstrated most clearly in the hematopoietic system. Evidence for stem cell function in the hematopoietic system has come from controlled laboratory experiments and as a consequence of human exposure to massive irradiation during armed conflict. World War II was brought to an end dramatically in August 1945 with the dropping of atomic bombs on the cities of Hiroshima and Nagasaki, Japan. In the wake of the devastation and human suffering of these events, several hundred thousand Japanese civilians and soldiers were exposed to lethal and sublethal doses of irradiation. Examination of the affected people included, but was not limited to, the ablative effects of irradiation on the body’s hematopoietic system. Observation and treatment of these patients led to several scientific reports confirming the postulated existence of stem cells that are responsible for the continuous production of all circulating blood cells. Subsequent studies performed on laboratory rodents detailed the detrimental effects of irradiation on the hematopoietic system as well as the ability of bone marrow transplantation to correct such anomalies. Hematopoietic repopulation was established by transplanting clonogenic marrow cells, which …

Water status and LPO in rat tissues during massive blood loss and irradiation with He-Ne laser.

We revealed a relationship between water balance and LPO in the myocardium, liver, and blood plasma during massive blood loss and irradiation with He-Ne laser. Low-intensity laser irradiation of the plasma inhibits LPO and normalizes water balance in rat tissues during massive blood loss.

Photokinetic behaviour of biphotochromic supramolecular systems: Part 2. A bis-benzo-[2H]-chromene and a spirooxazine–chromene with a ( Z-)ethenic bridge between each moiety

The photochromic behaviour of two new bichromophoric molecules (a symmetric one, formed by two 3,3-diphenyl-[3H]-naphtho[2,1-b]pyran moieties, and an asymmetric one, formed by a naphthopyran and a spiro[indoline-naphthoxazine] moiety) linked through an ethenic double bond has been studied. A model compound, where the chromene moiety is linked to a naphthalene group, was also investigated for comparison purpose. The photochemical and thermal evolution of the bichromophoric molecules were followed spectrophotometrically and by high performance liquid chromatography (HPLC). The photochromic reaction was found to be only partially photoreversible. Massive irradiation with visible light led to degradation. The reaction mechanism for these molecules containing a chromene moiety is characterised by an intermediate, which thermally evolves to different products. The quantum yield of formation and the first-order kinetic constant of the thermal evolution of the intermediate were determined. The identification of the photoproducts was helped by information from a parallel NMR study. Comparison of these results with those previously obtained on related monochromophoric and bichromophoric compounds allowed reasonable photoreaction mechanisms to be proposed.

Desmoid Fibroma: are We Ready to Avoid the Surgical Treatment?

Thirty years experience of treatment of soft tissue desmoid fibroma (Moscow Oncologic Institute) is presented. Efficacy of surgical treatment versus combined and radiation therapy was studied. The rate of relapse of extraabdominal desmoids after surgical treatment was 94%, after combined treatment with preoperative radiation therapy the relapse rate decreased up to 27.5% but after postoperative radiation therapy up to 53%. After radiation therapy the relapse rate was 15.7%. However radiation therapy has limitations related the necessity of massive tumor irradiation and application of high doses of irradiation that may cause postradiation affect of tissues. During subsequent search the original method of chemiotherapy (tamoxiphen, vinblastin, methotrecoat) was tested. This method allows to achieve the persistent remission in 81.3% of patients. Principles of therapeutic tactics in desmoid fibromas are formulated.

Long-term sequelae of Pelvis irradiation: Histological and microradiographical study of a femoral head

Despite the lack of radiological signs, a femoral head showed histological and microradiographical features of osteonecrosis, 54 years after massive irradiation of the right hip. Intertrabecular spaces were invaded by connectivo-vascular tissue with focal accumulation of mast cells, and several resorption foci were filled with mononucleated cells. Moreover, all the microradiographs showed peculiar hypercalcified lines, sometimes containing empty osteocytic lacunae, the origin of which is difficult to precise. This study suggests that massive irradiation of weight-bearing epiphyses may be responsible for particularly long-term hypovascularity, osteonecrosis and disturbed bone remodeling.

Cytogenetic Effects of Chemotherapy and Cranial Irradiation on the Peripheral Blood Lymphocytes of Children with Malignant Disease

Results of a cytogenetic analysis of peripheral blood lymphocytes of children with leukemia after massive chemotherapy and cranial irradiation, and of children with nephrosis after coritisone therapy and cyclophosphamide are presented. Prolonged intensive chemotherapy results in a significant rise in the number of chromatid aberrations after twelve months, and of chromosomal aberrations after 24 months of therapy. After cranial irradiation a sharp rise in chromosome aberrations is present for about three months. This drops after one year to levels present in cases with chemotherapy alone.

Aberrant Recovery of Protein Synthesis after Massive Irradiation of Arachis hypogaea, L. Cells In Vitro

Protein synthesis and respiration of 3 day old V-56R peanut (Arachis hypogaea, L.) cell-suspension cultures are reduced to 45-55% of controls immediately after a massive dose (500 Krad) of radiation. However, they apparently recovered during 3-4 days of postirradiation period. Recovery in protein synthesis and respiration continued and exceeded the control levels one week after radiation. Analysis of the proteins synthesized during the postirradiation period indicated that the distribution of radioactivity in labeled proteins is changed and large molecular weight proteins are directly or indirectly broken down to low molecular weight fractions. A significant increase in endogenous free amino acids is observed during the postirradiation period. Both respiration and protein synthesis started to decline 2 weeks after irradiation and levelled well below the controls during subsequent postirradiation period. Although quantitatively protein synthesis showed an apparent recovery after massive irradiation, the pr...

Induction of Giant Cells in Suspension Cultures of Arachis hypogaea, L. by Massive Irradiation

The growth of V-56R peanut (Arachis hypogaea, L.) cell-suspension cultures was inhibited as a function of dose (5-500 krad) of radiation, however, protein synthesis showed an immediate response only after a dose of more than 50 krad. Morphological observations made on the irradiated cells indicated that while cell division is completely arrested after a dose of 50-500 krad, cell expansion seems to be least affected and 50-60% cells become large filamentous giant cells. The frequency of giant cells increased during postirradiation period of 4-5 weeks. Radiation-induced giant cells showed an active cyclosis, denser cytoplasm and higher number of starch grains. Protein synthesis continued even after a massive dose (500 krad) of radiation at approximately 45-55% of controls, if the cells were incubated in fresh medium after irradiation, and showed an apparent recovery during postirradiation period. The effect of radiation on protein synthesis was also dependent on the age of the cultures and presence of condi...

Effect of serum from irradiated rats on gastrointestinal function.

A STRONG gustatory aversion results when an animal consumes a distinctively flavoured fluid during exposure to sublethal doses (10–30 r.) of ionizing radiation1. Similar aversive reactions are observed when wild rodents consume poisoned food baits2; or when laboratory rats drink flavoured water and are subsequently injected with an emetic drug3; or when these animals are injected with a small amount of serum (1.2 ml.) from a donor exposed to massive irradiation (30 krad) from cobalt 60 (ref. 4).

Adult bronchopulmonary dysplasia: the similarity in roentgen and histopathologic appearance between some cases of oxygen toxicity, radiation pneumonitis, and postcytotoxic nonspecific bronchopneumonia.

Bronchopulmonary dysplasia has been described by Northway et al. (1) as a disease of the lung, especially in infants with severe respiratory distress syndrome, who have been treated with prolonged artificial ventilation and 80 to 100 per cent concentration oxygen. It was represented as a prolongation of the healing phase of the respiratory distress syndrome combined with a generalized pulmonary oxygen toxicity, involving mucosal, alveolar, and vascular changes. Simultaneously, similar changes were described by Nash and his co-workers (2), associated with oxygen therapy and artificial ventilation in 70 patients who came to autopsy after prolonged artificial ventilation in a mechanical ventilator. The gross appearance of these lungs was particularly important in that they were extremely heavy, usually exceeding 1,700 g combined weight as against a control weight of less than 1,200 g and in that they were deeply congested, inelastic, noncrepitant with markedly increased consistency, retaining the lung shape without collapse. We have gathered 11 cases in adults from our autopsy population with similar microscopic and gross findings in the past eighteen months. In these, the pulmonary changes were characterized by a uniform increase in lung weight, uniform poor aeration of the lungs, and microscopic evidence of septal edema, hyperplasia of alveolar lining cells, and remnants of hyaline membranes, consistent with the findings of bronchopulmonary dysplasia and oxygen toxicity as described by Northway et al. and Nash et al. The microscopic appearance is exemplified by the accompanying illustration (Fig. 1) which shows a prominent intra-alveolar fibrin exudate, hyaline membrane formation, marked thickening of the alveolar and interlobular septa with edema, and an extremely cellular fibroblastic proliferation and deposition of reticulin. Radiographically there is a considerable consistency of appearance in our cases (Fig. 2). Here one sees dense opacification of lung bilaterally with numerous interposed pseudocystic bleb-like areas of lucency, which histologically represent emphysematous foci. Interestingly, two of our patients were not treated with oxygen therapy. In one of these, the lesions apparently resulted from massive irradiation (Figs. 1, A and 2, A) to the mediastinum, involving adjoining lung also, given in a mantle fashion in accordance with our lymphoma protocol. In the second case, where no oxygen therapy was employed, there was massive chemotherapy with busulfan (Myleran) (Figs. 1, Band 2, B). Interstitial fibrotic changes have been described previously with longterm busulfan therapy (3, 4). The published microscopic appearances closely resemble those of our present cases. In the other cases in our series oxygen therapy, chemotherapy with cytotoxic agents, or irradiation in varying amounts was administered as indicated in the accompanying table (TABLE I).

MEDICAL NEWS

<h3>Bone Marrow Transplant 'Success' Linked To Tissue Matching Tests</h3> A two-year-old New York boy with Wiskott-Aldrich syndrome is surviving without major symptoms nearly two months after bone marrow transplants from his nine-year-old sister. Chimeric peripheral blood cells and a previously absent ability to synthesize isohemagglutinins indicate "the patient's immune system has been replaced by that of the donor." Application of tissue typing techniques—previously used mainly for renal transplants—is the key to continued survival (as of Nov 14) of the boy, University of Wisconsin clinicians believe. In contrast to transplants of other organs, bone marrow infusion carries more than the danger of rejection, said Fritz H. Bach, MD. "Immunologically competent cells and their precursors are transplanted, raising the difficulties of graftversus-host reactions." <h3>Clinical Response 'Good' In Three</h3> Clinicians in several nations have attempted marrow transplants for leukemia and massive irradiation over the past

Mitochondrial resistance to massive irradiation in vivo: V. Repair and the repair overshoot

An immediate mitochondrial response to injury is apparent when megarad doses of ionizing radiation are absorbed by quiescent fruit cells. Mitochondrial oxidative activity, ADP O , and respiratory control were used as indices of radiation injury and repair. The time-course of recovery and the response to split radiation doses reveal an overcompensation of the initial injury. This is interpreted to result from an overshoot either in repair processes or in de novo synthesis of mitochondria.

Mitochondrial resistance to massive irradiation in vivo—II : Density-gradient distribution of the mitochondrial fraction and associated enzymes

Sucrose density gradient centrifugation was utilized to discern effects of massive γ-irradiation (250 and 1000 krad) on the mitochondrial fraction in pear fruit cells. Protein content and three enzymes, cytochrome oxidase, catalase and acid phosphatase were used to detect the presence of specific organelles along the sucrose gradient. A dose of 250 krad deterred mitochondrial fragmentation and losses in enzyme activities known to occur in the unirradiated, aging control cells. A 1000-krad dose, however, produced obvious manifestations of massive stress to the fruit and augmented the degenerative processes associated with cellular aging.

Mitochondrial resistance to massive irradiation in vivo—I : Structural stability as evidenced by electron microscopy, membrane functions, and fatty acid composition

Mitochondria were isolated from fruit (cherries and pears) which had absorbed from 250 to 1000 krad of ionizing radiation. A lack of obvious structural damage or changes in several membrane characteristics suggest a marked radioresistance of the mitochondria.

Mitochondrial resistance to massive irradiation in vivo: IV. Suppression and recovery in rate of amino acid incorporation into mitochondrial protein

In vivo synthesis of mitochondrial protein has been measured as a function of radiation dose and postirradiation time. A dose of 250 Krad will suppress incorporation of leucine- 14C into mitochondrial protein by about 50%. In 24 hours the rate of incorporation is nearly recovered. A 1000 Krad dose, however, results in a much greater and permanent inhibition. These observations, in concert with other responses of fruit mitochondria to massive irradiation, suggest a capacity in mitochondria for repair or reconstitution of massive radiation damage.

Mitochondrial resistance to massive irradiation in vivo: III. Suppression and recovery of respiratory control

Mitochondria capable of respiratory control have been isolated from pear and apple tissues. Respiratory control, as an index of mitochondrial integrity, was then used to assess dose-dependent radiation damage and postirradiation recovery in vivo. Dose thresholds for suppression of respiratory control lie between 250 and 500 Krad. Recovery of respiratory control will occur 48 hours after doses of 500 and 750 Krad. There is no recovery in a similar period following a dose of 1000 Krad. Such marked radioresistance on the part of fruit mitochondria is in concert with other responses of this tissue to ionizing radiation. Cytological implications are discussed with reference to the established radiosensitivity of animal mitochondria.

Fat-absorption analysis in experimental animals showing the radiation syndrome.

AS IS generally known, radiation injuries of the gastrointestinal tract after massive total-body irradiation play an important part in the death of experimental animals. The digestive system is highly responsive even to relatively low doses. The effects manifest themselves partly in functional damages, such as atony and loss of motility, and partly in morphological changes. It is common knowledge that the absorption of sugar, fat, vitamins soluble in fat, and electrolytes decreases as early as twenty-four hours after irradiation (1). Changes in the ultrastructure of intestinal mucosa are shown by means of electron-microscopic examinations (2) after the application of only 100 R, although morphologically this ultrastructure corresponds roughly to the picture of intact mucosa, with large granules of an in-homogeneous structure in the cytoplasm. With reservations, the authors believe these appearances indicate various metabolic states in structures that form the enzymatic protoplasm of the cell. Excretion of...