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The growth of two murine hemangioendotheliomas intracranially, subcutaneously, and in culture, and their comparison with human cerebellar hemangioblastomas: morphological and immunohistochemical studies.

Two thorium dioxide-induced murine hemangioendotheliomas, 42021 TCT and 44347 TST, were grown subcutaneously (for up to 22 and 15 passages respectively) or intracranially (single passage) and were adapted to culture as a monolayer and, in a limited fashion, in an organ culture system or in rotary suspension. They remained viable and malignant following 20-21 years of storage in liquid nitrogen, and had ultrastructural similarities to human hemangioblastomas. The murine tumors were positive for Griffonia (Bandeiraea) simplicifolia isolectin B4 binding, establishing their endothelial nature; however, unlike human hemangioblastic tumors, they did not cross-react with antisera to human factor VIII or fibronectin and they did not demonstrate Ulex europaeus type I lectin (UEA I) binding (as is also the case for non-neoplastic murine vascular endothelial cells). A variety of morphological cell types in cultures derived from the tumors were also positive for Griffonia (Bandeiraea) simplicifolia isolectin B4 binding. Both murine hemangioendotheliomas, when implanted in the cerebrum, were potent inducers of reactive gliosis, but there was no evidence of uptake of glial fibrillary acidic protein. Unlike the human cerebellar hemangioblastomas, murine tumors were malignant and invasive and did not contain stromal cells, nor did they demonstrate Weibel-Palade bodies or extensive pinocytotic activity. Thus, the murine tumors appear to more closely resemble angiosarcomas or epitheloid hemangioblastomas than the cerebellar hemangioblastomas.

Animals↗

Observations on the regulation of cell volume and metabolic control in vitro; changes in the composition and ultrastructure of liver slices under conditions of varying metabolic and transporting activity.

Liver slices incubated at 1 degree C underwent swelling of both cellular and intercellular compartments, as judged by electronmicroscopy. The ultrastructure showed marked changes, including disorganization of the cytocavitary network and plasma membrane and alterations of mitochondria. Restoration of metabolically favorable conditions (oxygenated medium at 38 degrees C) caused a nearly complete recovery of ultrastructure closely associated with extrusion of water; measurements of inulin space and electronmicroscopy both indicate a recovery of cell volume, with intercellular spaces remaining somewhat expended. The fluid lost was a roughly isotonic solution of Na+ and Cl-, while K+ was reaccumulated in exchange for Na+. Cyanide prevented recovery. Ouabain and oligomycin each partially prevented fluid extrusion, but had little effect on ultrastructural recovery except to induce intracellular vesicles containing particles of thorium dioxide derived from sinusoidal spaces. The vesicles were, however, markedly different in form with each inhibitor. There are, thus ouabain-sensitive and insensitive components of volume regulation; the former appears to depend on the coupled transport of Na+ and K+ and the latter, we suggest, on a secretion of Na+ and Cl- into vesicles which release their contents into the bile canaliculi by an oligomycin-sensitive mechanism. Mitochondria showed conformational changes between orthodox and condensed forms, but these could not be directly related to tissue energy states; the numbers of mitochondrial dense granules bore a closer relation to tissue ATP.

Animals↗

[Radiation exposure and risk of radon in the room air of Swiss houses].

The radioactive noble gas radon, a member of the natural decay chains of uranium and thorium, enters the indoor environment in regionally highly diverging amounts. Subsoil of dwellings, building materials and drinking water are the main sources. In Switzerland and in many other countries, exposure of the lung tissue to the short lived radon decay products is the most important component of the radiation dose of the general public. Annual doses in areas with crystalline rock of high uranium content may reach the limits set up for occupational exposure. However, a clear link between cumulative exposure to radon daughters and elevation of the lung cancer incidence exists only for underground miners. The majority of human epidemiological studies point to a linear dose effect relationship. The indoor radon levels are determined by geology, building materials and techniques, climate and behaviour of the occupants. Experiences from Scandinavia and the Northern parts of America clearly indicate the possibility of cost-efficient remedial measures to reduce indoor radon levels.

Air Pollution, Radioactive↗

Quinoline-8-ol-immobilized Amberlite XAD-4: synthesis, characterization, and uranyl ion uptake properties suitable for analytical applications.

Amberlite XAD-4 has been functionalized by coupling it with 5-aminoquinoline-8-ol after acetylation. The resulting resin has been characterized by elemental analysis and IR spectra and has been used for preconcentrating uranyl ions prior to its determination by spectrophotometry. The optimum pH value for quantitative sorption is 4-6, and desorption can be achieved by using 5 mL of 1 mol L(-1) HCl. The sorption capacity of the resin is 11.5 mmol g(-1). The effect of various cations and anions on the preconcentration of uranium in conjunction with the determination procedure has been studied and we have found that none of the ions interfere except thorium. The enrichment factor for preconcentration of uranium was found to be 200. Ten replicate determinations of 40 micro g of uranium present in 1 L of sample gave a mean absorbance of 0.185 with a relative standard deviation of 2.64%. The detection limit corresponding to three times the standard deviation of the bank was found to be 2 micro g L(-1). The validation of the developed preconcentration procedure was carried out by successfully analyzing standard marine sediment reference material. The uranyl content of sediment and soils is estimated by spectrophotometry after its preconcentration with the above chelating resin.

Journal Article↗

Detection of trace radioisotopes in soil, sediment and vegetation by glow discharge mass spectrometry.

The possibility for the determination of some radioisotopes of cesium, strontium, plutonium, uranium and thorium by glow discharge mass spectrometry (GDMS) in soils, sediments and vegetations is investigated. The preparation of samples is described as a combination of the use of a conductive host matrix and a secondary cathode in order to decrease the dilution effect of the blending material for the trace level determination and to gain a stable discharge. Effects of interferences arising from the nature of the conductive host matrix and of the secondary cathode on the sensitivity of the method are discussed. The determination of (137)Cs and (90)Sr has been attempted and the results obtained were in agreement with those from other analytical techniques. Accuracy, internal and external precisions have been also evaluated. GDMS is shown to be a helpful technique for the determination of radioisotopes in environmental samples. Radioisotopes can be determined according to the matrix of the sample (e.g. grass), also in presence of isobaric interferences. However, limitations still exist on the application of GDMS.

Journal Article↗

The Hiroshima thermal-neutron discrepancy for (36)Cl at large distances. Part II: Natural in situ production as a source.

For Hiroshima, a large discrepancy between calculated and measured thermal-neutron fluences had been reported in the past, for distances to the epicenter larger than about 1,000 m. To be more specific, measured (36)Cl concentrations in environmental samples from Hiroshima were too large at these distances, and the ratio of measured to calculated values reached about 70, at a distance of 1,800 m. In an attempt to identify other sources that might also produce (36)Cl in Hiroshima samples, the role of cosmic rays and of neutrons from natural terrestrial sources was investigated. Four reaction mechanisms were taken into account: spallation reactions of the nucleonic (hadronic) component of the cosmic rays on potassium (K) and calcium (Ca) in the sample material, particle emission after nuclear capture of negative muons by K and Ca, reactions of fast-muon induced electromagnetic, and hadronic showers with K and Ca, and neutron capture reactions with (35)Cl in the sample where the neutrons originate from the above three reaction mechanisms and from uranium and thorium decay. These mechanisms are physically described and mathematically quantified. It is shown that among those parameters important for the production of (36)Cl in granite, the chemical composition of the sample, the depth in the quarry where the sample had initially been taken, and the erosion rate at the site of the quarry are most important. Based on these physical, chemical, and geological parameters, (36)Cl concentrations were calculated for different types of granite that are typical for the Hiroshima area. In samples that were of these granite types and that had not been exposed to atomic bomb(A-bomb) neutrons, the (36)Cl concentration was also determined experimentally by means of accelerator mass spectrometry, and good agreement was found with the calculated values. The (36)Cl signal due to natural in situ production was also calculated in granite samples that had been exposed to A-bomb neutrons at distances up to 1,500 m from the hypocenter. It is demonstrated that, for granite samples from Hiroshima exposed to A-bomb neutrons beyond distances of about 1,300 m from the hypocenter, the (36)Cl signal is dominated by natural in situ production.

Biophysical Phenomena↗

Exposure to polymeric materials in vascular soft-tissue sarcomas.

UNLABELLED: Known etiologic factors related to endothelial angiosarcomas are exposures to arsenic, thorium dioxide, therapeutic irradiation, and certain congenital diseases. Little is known on the etiology of hemangiopericytomas. Since 1974, several reports have appeared on a distinct relationship between the exposure to vinyl chloride monomers and angiosarcomas of the liver. The early reports on this matter provided the reason to collect the occupational histories of vascular sarcomas accumulated since that time. METHODS: Data on the occupational histories of patients with different forms of angiosarcomas, treated between 1975 and 1995 in two institutions, were prospectively collected and analyzed. In this personal series the only selection criteria were the referral of patients for postoperative or palliative irradiation and their personal care by the author. FINDINGS: Among 21 adult cases of vascular sarcomas there were 4 patients with occupational exposure to vinyl chloride (VC) either alone or together with other artificial polymers. Seven other patients showed exposure to several plastics or resins other than VC. Altogether, 11 of 21 (52%) of the explored patients were found to have been exposed to artificial polymeric materials over a mean period of 18 years. The patients without such exposure were 4 farmers, 2 house-wives, and 1 woodworker, telephonist, mason, and inland revenue official, respectively. Two cases were radiation-induced. The series contained no angiosarcoma of the liver. INTERPRETATION: This study offers new evidence of the occurrence of vinyl-chloride-induced angiosarcomas outside the liver and confirms observations that have previously been published in case reports. Moreover, it may be suspected from this analysis that polyvinyl chloride and its monomers are not the only polymeric materials that may contribute to an induction of angiosarcomas in humans. Repeated occupational histories have to be taken from the patients to achieve data of the greatest value, since there are many professional activities that do not primarily lead to the assumption of specific exposure to polymeric materials.

Adult↗

The pericellular boundary layer modulates acetylcholine receptor stability in cultured myotubes.

Degradation of acetylcholine receptors in cultured chicken myotubes was measured by release into the medium of radioactivity from 125I-labeled alpha-bungarotoxin. Disturbance of the pericellular boundary layer by stirring of the culture medium shortened the half-life of receptor in the membrane from 24 to 12 h. The effect could not be explained by dissociation of toxin-receptor complexes or by conditioning of the bulk phase of the medium. The rates of synthesis and degradation of total cell protein and the degradation of lactoperoxidase-iodinated surface protein were not affected by medium stirring. The loss of glucosamine-labeled material from the cells was enhanced by stirring, however, and this resulted entirely from the increased shedding of high molecular weight glycosubstances from the cells. Cells in stirred cultures contained lower levels of surface coat material stainable with colloidal thorium. These results indicate that glycosubstances of the pericellular matrix protect ACh receptors from degradation.

Animals↗

Digestion of prey in foraminifera is not anomalous: a correlation of light microscopic, cytochemical, and HVEM technics to study phagotrophy in two allogromiids.

Correlative light, high-voltage electron and conventional electron microscopic methods were used to investigate digestion in two allogromiid foraminiferans, Allogromia sp., strain NF, and A. laticollaris Arnold. Microscopic observations showed that bacterial prey are phagocytosed by reticulopodia and are transported to the allogromiid cell body within blister-like phagosomes. Larger prey (algae, diatoms) are transported along the reticulopodial surface and are either stored extrathalamously or phagocytosed at the oral opening (peduncle). Studies of allogromiids optimally fixed and labeled with an extracellular-space label (colloidal thorium) showed that phagocytosed prey are completely enclosed by a plasma membrane envelope; this finding was corroborated by a serial-section three-dimensional reconstruction of the oral zone of one allogromiid. Cytochemical staining for acid phosphatase showed that lysosomes are absent from reticulopods but abundant in the cell body, particularly in the oral zone cytoplasm. We conclude that digestion in allogromiid foraminiferans is accomplished by a vacuole-based digestive apparatus and not by extracellular digestion within a lacunary system, as has been suggested in earlier studies.

Acid Phosphatase↗

Identification of transferrin as the principal neptunium-binding protein in the blood serum of rats.

The binding of 239Np(V) to blood serum components of rats was examined in vivo and in vitro. After gel filtration of the serum using a Sephacryl S-300 column, 98% of the applied activity appeared with protein fractions representing coeluted albumins and transferrin. A separation of the albumin- and transferrin-proteins by ion-exchange chromatography using DEAE-cellulose showed the 239Np being entirely bound to the iron-carrier protein transferrin. The high elution yields from the ion-exchange columns, greater than 90%, suggest that the binding may be quite strong. The binding capacity of transferrin for neptunium in vivo was found to decline when the iron level in blood serum was increased. Precipitation experiments showed that 84 +/- 2% of the 239Np was precipitated with 10% (w/v) trichloracetic acid, 77 +/- 3% with 90% ethanol but only 6 +/- 1% with saturated ammonium sulphate at pH 7.4. The available data indicate that as for plutonium, thorium, americium and curium, the iron transport protein, transferrin, may be the main carrier protein for neptunium in mammalian blood serum.

Animals↗

Enhanced radioactivity due to natural oil and gas production and related radiological problems.

Increased gamma radiation detected incidentally a few years ago in a North German oil field was traceable to radioactive scale. At the request of the Federal Ministry of the Interior a survey program was then established for dose rate measurements at various production sites, assessment of the radionuclide content of brines and scale and the Rn-222 content of natural gas. Dose equivalent rates of up to 50 mu Sv/h have been measured at the external surface of storage tanks for brines, but 73% of the 160 sites investigated did not show an increase above the natural background. Brines from gas fields contained Ra-226 of up to 286 Bq/l and scale of up to 1 kBq/g. In brines and scale from oil fields Ra-228 was usually the predominant radionuclide. Some samples contained "unsupported" Pb-210 and even Ac-227, too, but practically no uranium or thorium. The Rn-222 concentrations in natural gas samples varied between 0.004 and 4 Bq/l with a mean value of 0.6 Bq/l. It is shown that the radiation exposure due to natural gas consumption is negligible but some other problems or radiological relevance are recognized.

Fossil Fuels↗

Investigation of mine and industry dumps in the FRG in relation to a possible release of natural radioactive elements.

More than 350 dumps of mines and industries in two federal states of the FRG were recorded, measured radiometrically, evaluated, and some of them sampled. Most of the mine dumps belonged to old and smaller residues from lead/zinc and iron ore mining, while the largest depositions contain tailings of modern ore beneficiation or flyash disposal. All mine dumps from uranium exploration in Baden-Württemberg and Bavaria were investigated. The highest doses, up to 100 mSv/a, were found on the piles of the uranium exploration. These depositions, which are supervised and licensed, are followed, in terms of surface dose, by the old uncontrolled mine dumps of silver/cobalt mining with doses up to 20 mSv/a. The numerous porphyry and granite quarries show doses between 1 and 2 mSv/a, as do flyash and slag dumps. The lowest doses were found on the dumps of the hydrothermal Pb/Zn and iron ore deposits, while the slag piles of iron ore processing showed higher thorium values. Assays for Ra-226 and Pb-210 of the materials deposited confirmed the radiometric results. Analyses of seepage waters and gallery waters showed only very few values exceeding the derived drinking water concentrations.

Environmental Pollution↗

Occupational exposure to natural radiation.

Natural sources of radiation can make an important contribution to the exposures of people at work. Two areas of interest are work with minerals having elevated concentrations of activity and work in buildings where radon daughter concentrations are elevated. The Euratom Directive on ionising radiation requires that the handling of radioactive substances be reported to national authorities. National authorities may waive this requirement where the activity per unit mass is below 100 Bq g-1, or for solid natural radioactive substances, 500 Bq g-1. An investigation was undertaken in five factories to determine whether work with minerals having levels of natural activity below these might lead to significant doses. Models based on the data collected were used to relate the activity in the minerals to the effective dose equivalent arising from gamma radiation, inhalation of radon daughters, and intake of long-lived activity. These assessments show that the activity concentration at which exposures to airborne dust could lead to doses equal to one-tenth of the dose limit for workers are 0.3 Bq g-1 for thorium-232 and 1 Bq g-1 for uranium-238. Above these values, radiological supervision may be necessary. In a separate study, measurements of radon daughter concentrations were made in seventy workplaces. Concentrations in some premises approached or exceeded the derived air concentration for occupational exposure. The highest concentrations were found in premises with low ventilation rates.

Air↗

The effects of human activities on natural radiation exposure: health and regulatory implications.

A decade ago, interest in "enhanced" natural radiation was focused primarily on localized industrial activities, e.g., uranium, radium, thorium and phosphate production. Recognition that all human activities influence natural radiation exposure, and that indoor radon exposure is particularly sensitive to such activities (building construction practices, occupant life-styles) has added a new dimension to the problem. Public health assessments must address the problem of high individual risks of lung cancer as well as substantial population risks that are only minimally ameliorated by reduction of high exposures. In the United States, Federal, State, and local government agencies are collaborating with the private sector in developing the information needed for public guidance. Voluntary standards relating to building construction practices are likely to be developed.

Environmental Exposure↗

Electron microscopical x-ray microanalysis of mineralization nodules and several other tissue compartments in fetal bone.

Several chemical components are involved in bone and cartilage mineralization. Acid glycosaminoglycans (GAG) form one class of these components. In this study, the possible presence of sulfated GAG in areas of beginning bone mineralization was investigated. We analyzed areas containing acid groups, which were made visible with positive colloidal ThO2, by means of x-ray microanalysis. Four tissue compartments were internodular matrix, and noncalcified cartilage matrix. Sulfur proved to be present in a higher concentration in the mineralization nodules than in the osteoid, whereas no significant difference could be demonstrated between the sulfur concentrations in mineralized internodular matrix and osteoid. The ratio of the sulfur content between the mineralization nodules and the cartilage matrix is significantly lower than the corresponding thorium ratio. This difference suggests that acid groups different from sulfate groups occur in a relatively larger amount in mineralization nodules than in cartilage matrix.

Animals↗

Quantitative energy-filtered image analysis in cytochemistry. II. Morphometric analysis of element-distribution images.

A combination of energy-filtered electron microscopy (EFEM) and an image-analysis system (IBAS/2000) is used for a morphometric analysis of chemical reaction products in cells. Electron energy-loss spectroscopic element-distribution images are acquired from cytochemical reaction products in a variety of cellular objects: (1) colloidal thorium particles in extra-cellular coat material, (2) iron-containing ferritin particles in liver parenchymal cells, (3) barium-containing reaction products in endoplasmic reticulum stacks, (4) elements present in lysosomal cerium- and barium-containing precipitates connected with acid phosphatase (AcPase) or aryl sulphatase (AS) enzyme activity. Areas or area fractions are determined from such element-distribution images by application of an objective image segmentation method. By superposition of two or more element-distribution images, mutual element relations are qualitatively established in lysosomal cerium- and barium-containing precipitates connected with acid phosphatase (AcPase) or aryl sulphatase (AS) enzyme activity. By comparing electron spectroscopic images (ESI) with element-distribution images, the mutual contrast per element relations are quantitatively investigated. The obtained gain in resolution in such electron energy-loss spectroscopic element-distribution images will be explained and discussed.

Animals↗

High-performance liquid chromatographic method for simultaneous determination of clodronate and some clodronate esters.

A quaternary alkylmethylamine-bonded stationary phase has been used for the liquid chromatographic resolution of bisphosphonates. Clodronate and three of its esters were separated by this technique. Nitric acid (30 mM) was used as the mobile phase. The effect of the pH of the mobile phase on the retention, resolution, capacity factor and theoretical plates of the column was examined. Thorium-ethylenediaminetetraacetic acid-xylenol orange mixed ligand complex was used as a postcolumn reagent for bisphosphonates. Bisphosphonates react quantitatively with this complex in slightly acidic solutions, and a change in the absorbance of postcolumn reagent is used as a measure of the bisphosphonate concentration. The relative standard deviation (R.S.D.) values for samples in aqueous solutions were in the range 2.3-15.5% (area) and 1.7-5.9% (height). The detection limits for different compounds, Cmin, varied from 0.3 to 1.4 mg/l (area) and from 0.3 to 0.5 mg/l (height). In urine samples the R.S.D. (%) varied from 3.1 to 18.9 (area) and from 1.1 to 6.3 (height). The linear dynamic range was from the detection limit up to 16 mg/l.

Chromatography, High Pressure Liquid↗

Rapid and precise micro-methods for quantitating active components in commercial bone scintigraphy kits--II. Diphosphonates.

Two parallel, independent micro-methods for diphosphonate determination are presented. These procedures are based on the interference of diphosphonate with the formation of cation-morin (3,5,7,2',4'-pentahydroxyflavone) complexes. In the spectrophotometric method, a change of the absorbance of thorium-morin complex is used as a measure of diphosphonate concentration. In the fluorimetric method, a decrease of the fluorescence of aluminium-morin complex is used. Both methods: (1) quantitate methylene-diphosphonate in the range of 5-40 x 10(-9) M with a coefficient of variation of less than 1%; (2) are specific and interference-free in commercial kits control; (3) are operative with other diphosphonates; and (4) are adaptable to the analysis of chromatographic eluents.

Bone and Bones↗