Accumulation of radionuclides from radioactive substrata by some micromycetes.

Overgrowing (interaction) and dissolution of intact and milled hot particles by various micromycetes were studied under laboratory conditions. Hot particles used for the investigation originated from the Chernobyl accident release and atomic bomb testing sites. The micromycetes investigated were mitosporic fungi mainly isolated from the Chernobyl site and vicinity. Most of the fungal species and strains showed a tendency to grow towards the hot particle, overgrow it and dissolve it after prolonged contact. The accumulation (absorption and adsorption) of radionuclides from intact hot particles was generally more intensive for (152)Eu than for (137)Cs by a factor of about 2.6-134, while in experiments with milled samples the (152)Eu and (137)Cs accumulation was similar, except for some fungal species, which showed higher (152)Eu than (137)Cs sorption. It could be shown that the main factors influencing Cs and Eu accumulation in fungi are: fungal species and strains and the size and composition of the hot particle.

Gender-related plasma levels of progesterone, interleukin-8 and interleukin-10 during and after cardiopulmonary bypass in infants and children.

BACKGROUND: It is known that proinflammatory and anti-inflammatory cytokines are released during and after cardiopulmonary bypass (CPB) in infants and children. Sex steroids are known to have immunomodulatory functions, and release of the anti-inflammatory cytokine IL-10 is stimulated by progesterone in vitro. The purpose of the present study was to investigate the plasma levels of progesterone, IL-8 (proinflammatory cytokine) and IL-10, and to relate them to sex and postoperative morbidity. METHOD: Eighteen infants and children (eight female) undergoing CPB were prospectively studied. Plasma levels of progesterone, IL-8 and IL-10 were determined before and 10 min after the start of CPB, and immediately after CPB; and 6 h, 24 h, 3 days and 7 days postoperatively. Organ dysfunction was identified on the basis of arbitrarily defined criteria. RESULTS: After CPB, all patients showed significant increases in plasma levels of progesterone, IL-8 and IL-10. Plasma levels of IL-10 were significantly higher in female patients, except for during the immediate postoperative period. According to the criteria used, six out of 10 male patients, but none of the female patients developed multiple organ dysfunction (MOD). CONCLUSION: The present study shows that CPB induces a significant and marked increase in plasma levels of progesterone in infants and children. Studies of administration of progesterone-blocking substances to male and female animals may help to elucidate the roles of sex and progesterone in the setting of CBP.

Classification of hot particles from the Chernobyl accident and nuclear weapons detonations by non-destructive methods.

Both after the Chernobyl accident and nuclear weapon detonations, agglomerates of radioactive material, so-called hot particles, were released or formed which show a behaviour in the environment quite different from the activity released in gaseous or aerosol form. The differences in their characteristic properties, in the radionuclide composition and the uranium and actinide contents are described in detail for these particles. While nuclear bomb hot particles (both from fission and fusion bombs) incorporate well detectable trace amounts of 60Co and 152Eu, these radionuclides are absent in Chernobyl hot particles. In contrast, Chernobyl hot particles contain 125Sb and 144Ce which are absent in atomic bomb HPs. Obvious differences are also observable between fusion and fission bombs' hot particles (significant differences in 152Eu/l55Eu, 154Eu/155Eu and 238Pu/239Pu ratios) which facilitate the identification of HPs of unknown provensence. The ratio of 239Pu/240Pu in Chernobyl hot particles could be determined by a non-destructive method at 1:1.5. A non-destructive method to determine the content of non-radioactive elements by Kalpha-emission measurements was developed by which inactive Zr, Nb, Fe and Ni could be verified in the particles.

The long-term decrease of 90Sr availability in the environment and its transfer to man after a nuclear fallout.

Due to its long physical half-life, and the fact that its long-term mobility in the environment as well as its radiotoxicity is higher than that of 137Cs, the long-term bio-availability of 90Sr in the environment is of importance with regard to the long-term population exposure after fallout from nuclear weapons detonations or a severe reactor accident. It will also substantially influence the time-span required until re-utilisation of highly contaminated territory is possible again. An assessment of the long-term decrease of the activity concentration in all foodstuffs relevant for internal exposure after severe 90Sr fallout was performed. The observed effective half-lives were approximately 1.8-2.1 years in the first 2-3 years after the end of fallout and 8-10 years in the following three decades. This is equivalent to a biological half-life of about 13.2 years and results in a total 50 year dose of 6.2 times the first year exposure. Due to this decline in 90Sr-availability, the average annual activity intake of 90Sr in Austria has decreased from 840 Bq at the climax of the nuclear weapons tests to about 42 Bq in 1997 for adults, and from 500 Bq to about 35 Bq for 1 year old infants. This is equivalent to a 90Sr ingestion dose of 1.2 microSv for adults and 2.5 microSv for 1 year old infants in 1997 or less than 0.4% of the ingestion dose by natural radionuclides in the diet.

Design and dosimetry of a novel 90Y beta source to prevent restenosis after angioplasty.

PURPOSE: Post-dilatation irradiation of the vessel wall is currently under investigation for prevention of restenosis after balloon dilatation. For the irradiation, special sources were designed for animal experiments which would give equivalent irradiation conditions and doses to the vessel wall that would later be employed for human application. METHODS AND MATERIALS: For the planned irradiations, a specially designed yttrium-wire of 0.45-mm diameter coated with a thin shrink tube to prevent contamination was deployed. Several leakage tests applied before and after application proved that the irradiation source was leakproof. Dosimetry was performed by using 0.1-mm-thick thermoluminescent dosimeters (TLD-100) calibrated against a primary standard. A shielding transport and application container was designed to facilitate the handling of the source during use, while reducing exposure of the medical personnel. RESULTS: The designed source proves to be flexible for the insertion into proximal coronary vessels, and positioning at the site of stenosis. It provides an optimum protection of the animal and requires little radiation protection efforts on behalf of the medical staff. Dosimetric calculations and measurements showed that a centering of the source inside the vessel could be achieved with a maximum deviation of 50% between maximum and average dose levels. CONCLUSION: A yttrium-90 beta brachytherapy source was designed which provides high flexibility within proximal coronary arteries, ensures an adequate centering inside the artery, and provides irradiation conditions to the vessel wall of the experimental animal comparable to the application inside a human artery.

Long-term effective decrease of cesium concentration in foodstuffs after nuclear fallout.

The long-term decrease in activity concentrations in various foodstuffs relevant for the long-term ingestion dose after a nuclear fallout is reviewed. The effective decrease observed in various countries of Central Europe after the Chernobyl accident are compared to the effective decrease observed after the atmospheric nuclear weapons testing. The presentation also includes the short-term decline immediately after fallout and the time course in the first year, which are relevant to the first year ingestion dose. The initial effective decrease is dominantly controlled by plant growth and follows an approximate half-life of 4.2 d in lettuce and spinach, and 10.5 d in grass during the growing season, resulting in an effective half-life of 33 d in milk. In order to avoid artifacts due to local fallout or plant variations or differences in the metabolism of single animals, the sampling of each foodstuff was spread over very large areas of production and a large number of samples including investigations in several individual provinces. The long-term decrease over the following years, which is vital for the long-term internal exposure, is slower but still follows an effective half-life for different foodstuffs: milk = 1.4-2.2 y, vegetables = 1.4-2.7 y, potatoes = 2.0-2.6 y, cereals = 3.0-3.4 y, and fruit = 1.2-1.6 y. Differences observed between the different products and areas are discussed. Half-lives in milk vary between three central-European countries from 708 d (Austria), to 663 d (Germany), to 538 d (Czechia). The observed effective half-life is much shorter than observed after nuclear weapons testing where a half-life of approximately 4.5-4.9 y was observed, which is explained by the weapons tests' fallout lasting for several years compared to the single short-term fallout after the Chernobyl accident.

Longterm reduction of caesium concentration in milk after nuclear fallout.

Time trends in activity concentrations in milk as observed in Austria after the Chernobyl accident are presented. Both the short term decrease immediately after fallout and the medium term decline in the years following the event are very important for estimating the total exposure to be expected from a given deposition. In order to avoid artifacts due to local fallout, plant variations, or differences in the metabolism of single animals, large areas of production were used for the observations. This was achieved by observations of activity concentrations in milk powder, produced in large milk powder plants in Austria. After an initial decay with an approximate half-life of 34 days for the period of May to August 1986, a slower decrease in activity was observed during the following years. Observed half-lives are in the range of 1.5-2.0 a. Differences in the decrease observed between the different producing areas are discussed. The radiocesium contamination of milk and milk products depends directly on its presence in grass or hay and therefore, time trends observed in milk correspond closely to the time trend in these fodders. Other foodstuffs which are also produced on grass and hay, such as beef or lamb, should therefore display similar decay patterns, except for the early period after fallout when the biological half-lives in the animals influences the decrease.

Estimate of the dose due to 90Sr to the Austrian population after the Chernobyl accident.

In order to estimate the contribution of 90Sr to the exposure of the Austrian population, the ratio of 90Sr to 137Cs in 126 food samples and nine drinking water samples was determined. From this and the average activity concentration of 137Cs in each type of food as obtained by the measurement of some 100,000 food samples after the Chernobyl accident, a good estimate of the average activity concentration of 90Sr in these food items could be obtained. Samples were investigated at various times after the accident to take into account possible changes with time in the 90Sr-activity concentration and its ratio to 137Cs. Also, pre-Chernobyl samples were measured to estimate the relative contribution of the reactor accident and the fallout of the atomic bomb testing to the intake of 90Sr. Assuming average food consumption, the intake of 90Sr for an adult person amounted to 168 Bq in the first year and 115 Bq in the second year after the accident, resulting in an effective dose equivalent of 5.9 muSv and 4.0 muSv, respectively. This is a minor fraction of the dose due to the ingestion of Cs isotopes, which amounted to 360 muSv in the first year and 97 muSv in the second year. For the one-year-old infant, a 90Sr intake of 96 Bq (10.5 muSv) in the first year and 65 Bq (7.1 muSv) in the second year is estimated. Approximately 50% of the intake in the first year and 70% of that in the second year are due to 90Sr from nuclear weapons testing.

Legionella pneumophila: identification in tissue sections by a new immunoenzymatic procedure.

A modified glucose oxidase immunoenzyme technique was shown to be highly sensitive and specific for detection of serogroup 1 Legionella pneumophila in 4% formaldehyde solution-fixed, paraffin-embedded tissue sections. There was complete concordance between infection with L pneumophila and detection of the organisms in tissue sections by glucose oxidase immunoenzyme staining. The L pneumophila organisms stained blue-black and were found within phagocytic cells as well as in the extracellular space. A cloud of blue-black pigment, probably representing diffusable antigen, was present in the extracellular spaces in the area of L pneumophila localization. No false-positive or false-negative reactions were found. This technique requires no specialized equipment, may be applicable to retrospective diagnostic problems, and can be adapted to routine diagnostic practice.

Immunoprophylaxis of respiratory syncytial virus infection in the infant ferret.

Infant ferrets can be protected from respiratory syncytical virus challenge at 3 days of age by gestational infection of their mothers. Ferrets acquire their immunity to respiratory syncytial virus postpartum via immunizing products of lactation. The level of protection against viral replication correlates with the maternal serum neutralizing titer or a concomitant factor. Passive administration of adult ferret serum with a neutralizing titer of 1:1024 or greater, either i.p. or orally does not confer immunity. A nonantibody-mediated protective mechanism appears to play an important role in protecting the infant ferret from respiratory syncytial virus replication. Our findings allow the testing of the efficacy of future human vaccines before human clinical trial.

Ontogeny of the ferret humoral immune response.

Infant ferrets are born with nearly undetectable immunoglobulin levels, but by 9 days of age the infant ferret serum contains 77, 29, and 13% of adult mean serum levels of IgG, IgA, and IgM. Transmucosal uptake of IgG by the infant ferret occurred for the first 30 days of life. The specific anti-respiratory syncytial virus neutralizing titer of whole milk was 5.5 times higher than maternal serum despite a lower concentration of immunoglobulins in the milk.

Improvement of the glucose oxidase immunoenzyme technic. Use of a tetrazolium whose formazan is stable without heavey metal chelation.

Glucose oxidase immunoenzymatic localization provides a simple way to show antigens in mammalian tissues, with no need for the quenching of endogenous nonspecific staining. The method is useful for the demonstration of many antigens in formalin-fixed, paraffin-embedded tissues. Improvement of this technic by the use of p-nitro blue tetrazolium chloride (NBT) as the disclosing reagent provides a stable, finely grained localization not possible with the previously used thiazolyl blue (MTT). The described modification makes available an ideal immunoenzymatic stain for the study of tissues at the level of the light microscope. This stain is especially useful for the examination of tissues with hemorrhagic or inflammatory lesions, since there is no endogenous background staining. Slides are permanent, and the technic can be used with peroxidase-labeled antibody to localize two antigens in the same tissue.

A new method for fluorescence immunoassay using plane surface solid phases (FIAPS).

A method distinguished by high sensitivity, low non-specific binding, easy handling, and broad applicability with respect to various antigens is described. Films of polymethyl-methacrylate with plane surfaces were selected as solid phase for adhesive or covalent binding of different antigens (DNA, histone, human, rabbit or goat immunoglobulins). Proteins were covalently bound to the films by the azide method (Orth and Brummer, 1972). Polymethylmethacrylate films thus coated had a negligible autofluorescence and gave minimal non-specific binding of protein. Coated films were used for specificity control of FITC-labeled antibody preparations and in the double antibody and sandwich techniques for detection of antibodies or antigens in sera from man, rabbit and goat. FITC-conjugated hyperimmune antibody, in some cases purified by immunoadsorption was used as second antibody in indirect techniques. The amount of fluorescent-labeled antibody bound per unit of surface area of film was measured by incident light with a Zeiss-Axiomat fluorescence microscope equipped for fluorescence photometry and an uranyl acetate glass plate was used as a standard. The technique appears superior to present methods of quantitative immunofluorescence analysis.

Vesicular stomatitis virus causes abortion and neonatal death in ferrets.

Vesicular stomatitis virus caused transplacental infection in ferrets, resulting in infant death. No clinically significant illness was observed in the adult, despite histological changes in the uterus, liver, and spleen.