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PubMed1986

In vitro function of radiocolloid-labelled monocytes.

Human monocytes in a mononuclear cell suspension were labelled specifically using 111In-Fe-colloid, with the ultimate goal of using them for monocyte kinetic studies in haematological malignancies. In order to examine the function of the labelled monocytes, in vitro function tests were performed on cell suspensions containing labelled or non-labelled monocytes. These tests were: phagocytosis of opsonized zymosan particles and ability of monocytes to mature into macrophages when cultured in glass tissue chambers. There were no significant differences in in vitro function between labelled and non-labelled monocytes. Cell viability was always greater than 90%. During culture, a rapid loss of monocyte-bound radioactivity took place. We conclude that the labelling procedures do not interfere with subsequent in vitro cell function. However, because of the rapid loss of cell bound radioactivity in vitro, monocytes labelled by this method do not seem suited for long-term studies in vivo.

Colloids↗

PubMed2003

Hepatic clearance of Sonazoid perfluorobutane microbubbles by Kupffer cells does not reduce the ability of liver to phagocytose or degrade albumin microspheres.

This study has been performed to examine which cells are responsible for the hepatic clearance of the new ultrasound contrast agent Sonazoid and to study whether uptake of these gas microbubbles disturbs the function of the cells involved. Sonazoid was injected into rats and perfused fixed livers were studied by electron microscopy, which revealed that the Sonazoid microbubbles were exclusively internalised in Kupffer cells, i.e. by the macrophages located in the liver sinusoids, and not by parenchymal, stellate or endothelial cells. This is the first demonstration of intact phagocytosed gas microbubbles within Kupffer cells. Uptake of the Sonazoid perfluorobutane microbubbles by the Kupffer cells following injection of a dose corresponding to 20x the anticipated clinical dose for liver imaging did not result in measurable changes in the uptake and degradation of radioactively labelled albumin microspheres previously shown to be a useful indicator marker for Kupffer cell phagocytosis.

Albumins↗

PubMed1983

Incidence of lung cancer among iron miners.

A study has been performed using 5300 iron miners from Lorraine (France) with ages ranging from 35 to 55 years, who were working, and had a normal chest radiography. 1173 workers were chosen randomly and given the following examinations: questionnaire, clinical examination and function tests (VC, FEV1, residual volume (RV), acetylcholine test, carbon monoxide steady-state test). This group of 1173 was followed for 5 years. 40 died and the exact causes of death were known. 13 had lung cancer, which is more than three times the number expected in the French male population of the same ages. All subjects who died from lung cancer were underground miners and, at the first examination, had a higher incidence of bronchitis and more functional defects than both the 27 who died from other causes and the underground miner group as a whole. The excess mortality due to lung cancer is discussed with regard to noxious agents that were measured (radioactivity, which was rather low, total and respirable dusts, Nox, CO) and with regard to both the work environment and duration of work.

Adult↗

PubMed1980

[Problems relating to the use of radioactively labelled bacteria in animal experiments. 3. Distribution of activities in mice, following parenteral administration of Pasteurella multocida labeled with various radionuclides].

When radioactively labelled fully developed Pasteurella (P.) multocida antigens were parenterally applied to mouse, through intravenous, intraperitoneal or subcutaneous routes, activity distribution was found to depend both the technique of application and the radionuclide used. This has given rise to the conclusion that activity distribution could be equated with whole-germ distribution only under certain conditions. Experimental antigen distribution, accordingly, reflected a complex process in which transport, location, and metabolism of bacteria had to be considered as being in conflict with the given host organism. Iodine labelled 125 was split off bacteria at relatively high rate and accumulated in the thyroid gland. When 59Fe was used, interpretation of distribution was rendered more difficult by propagation of iron through the organs of the host. Relatively favourable data were obtainable from the use of 3H or 14C which could be used in the form of nucleic acid precursors (orotic acid) in labelling Pasteurella. Intraperitoneal and intravenous forms of administration were found to be the same for intra-organic activity distribution. Retention of activity in liver, spleen, and lung was recordable and established from all the reviewed techniques for the application of P. multocida complete antigen. While maximum concentrations were measured between the first and third days, activities still were detectable after 14 days (period under review). Relatively high radioactivity was recordable from the digestive tract, within short time from the use of the parenteral procedures tested. This seemed to suggest passage of complete or incomplete P. multocida antigen through the mucous membranes of the gastro-intestinal tract.

Animals↗

PubMed2004

Development and validation of a fluorescence technology for both primary and secondary screening of kinases that facilitates compound selectivity and site-specific inhibitor determination.

The IQ Technology has been developed to serve as a homogeneous, universal detection platform for HTS of kinases and phosphatases. The technology is a direct, noncompetitive assay format that does not require antibodies or radioactive reagents to measure phosphorylation state. Fluorophore-labeled peptides are used as enzyme substrates, and kinase or phosphatase activity is quantitated by direct measurement of the phosphorylation state of the substrate. Phosphorylation is measured by the change in fluorescence intensity that occurs when a proprietary iron-containing compound binds specifically to phosphoryl groups on peptides. This change in observed fluorescence is proportional to the extent of phosphorylation of the fluorophore-labeled peptide. The technology provides a universal method that can be used with any peptide sequence and is insensitive to high concentrations of ATP. Inhibition at the ATP-binding site versus the phosphorylation site can be differentiated and compound selectivity identified using the same detection method as in the primary screen. The technology has been tested against a large number of detergents, organics, and other reagents found in reaction mixtures, and the detection method eliminates common issues associated with fluorescent and chromogenic compounds. The technology has been formatted for 96-, 384-, and 1,536-well microplate formats, and a representative Z' value of 0.7 was obtained. IC(50) values generated using this platform correlate with previously reported values, and screening of a small compound library was performed to evaluate the assay further.

Amino Acid Sequence↗

PubMed2001

Health evaluation of penguins (Sphenisciformes) following mortality in the Falklands (South Atlantic).

In the Falklands, heavy mortality of rock-hopper penguins Eudyptes chrysocome occurred during the 1985-86 breeding season. Starvation was diagnosed as the primary cause of death, possibly caused by a shortage of euphausiid crustaceans (krill) due to unusual meterological conditions. 'Puffinosis' may possibly have been a contributory factor; otherwise no conclusive evidence of infectious disease or toxicosis was found and also no evidence of radioactive contamination. In the 1986-87 breeding season no unusual mortality occurred, but 99 apparently healthy penguins were examined, i.e., rockhoppers Eudyptes chrysocome syn E. crestatus, gentoos Pygoscelis papua and Magellanics Spheniscus magellanicus. Full necropsies were carried out on 54. Tissue examinations were made for cadmium, copper, iron, manganese, mercury, lead and zinc. High tissue cadmium concentrations found in healthy birds in 1987 were similar to those in penguins which died in 1986, and therefore not considered to be of pathological significance. Although there has been no repetition of the unusually hot 1985-86 breeding season in the Falklands, penguins and other seabirds have had fluctuating breeding successes since then. The precise cause, including the roles of meteorological conditions and overexploitation of some forms of prey species, is unclear.

Animals↗

PubMed1984

[Essential thrombocythemia. Clinical, biological study and developmental study of 61 cases].

The 61 observations of primary thrombocythemia described in this report represent approximately 15% of the cases of polycythemia vera recorded by the authors over the same 18-year period. The group includes 35 females and 26 males, with a mean age of 62. The disease is usually discovered on routine blood tests (half of cases), and more rarely because of hemorrhagic or thrombotic manifestations. Splenomegaly is found in one-third of cases. Platelet count is permanently above 800 X 10(9)/l (mean : 1 500 X 10(9)/l); mild hyperleukocytosis (mean : 16 X 10(9)/l) with predominant neutrophil polynuclears is usual but myelemia is not constant (28% of cases) and always very moderate; red cell parameters are normal in three-fourths of cases, while the remaining patients have anemia, either due to iron depletion or not. Reticulinic myelofibrosis, usually minimal, is found in 40% of cases. Medullary karyotype is always normal, without chromosome Ph1. Platelet functional abnormalities are not constant and do not correlate with the magnitude of thrombocythemia. 51 patients (84%) received myelosuppressive therapy, mainly by busulfan or radioactive phosphorus. Most deaths were due to intercurrent causes and only one patient developed acute leukemia. 71% of patients are alive at five years and subsequent decrease in the actuarial survival curve is very gradual.

Busulfan↗

PubMed2006

Competitive effect of iron(III) on metal complexation by humic substances: characterisation of ageing processes.

Aiming at an assessment of counteractive effects on colloid-borne migration of actinides in the event of release from an underground repository, competition by Fe(III) in respect of metal complexation by dissolved organic matter was investigated for the example of Eu(III) as an analogue of trivalent actinides. Complexation with different humic materials was examined in cation exchange experiments, using (59)Fe and (152)Eu as radioactive tracers for measurements in dilute systems as encountered in nature. Competitive effects proved to be significant when Fe is present at micromolar concentrations. Flocculation as a limiting process was attributed to charge compensation of humic colloids. Fe fractions bound to humic acids (HA) were higher than 90%, exceeding the capacity of binding sites at high Fe concentrations. It is thus concluded that the polynuclear structure of hydrolysed Fe(III) is maintained when bound to HA, which is also inferred from UV-Vis spectrometry. The competitive effect was found to be enhanced if Fe and HA were in contact before Eu was added. Depending on the time of Fe/HA pre-equilibration, Eu complexation decreased asymptotically over a time period of several weeks, the amount of bound Fe being unchanged. Time-dependent observations of UV-Vis spectra and pH values revealed that the ageing effect was due to a decline in Fe hydrolysis rather than structural changes within HA molecules. Fe polycations are slowly degraded in contact with humic colloids, and more binding sites are occupied as a consequence of dispersion. The extent of degradation as derived from pH shifts depended on the Fe/HA ratio.

Benzopyrans↗

PubMed1988

The effect of riboflavin deficiency in rats on the absorption and distribution of iron.

1. Riboflavin may play a part in the transport of iron across the gastrointestinal mucosa. Fe absorption was measured in the rat by monitoring whole-body retention of a dose of 59Fe using a small-animal gamma-counter. 2. Female Norwegian Hooded rats were fed on a diet deficient in riboflavin (B2-) from 5 weeks of age. Control animals, fed on a complete diet (B2+), were weight-matched to rats fed on the B2- diet. After 7 weeks all rats were fed on a test meal extrinsically labelled with 59Fe and whole-body radioactivity measured for 15 d. 3. Riboflavin deficiency was associated with a reduction in the percentage of the dose absorbed and an increase in the rate of loss of Fe post absorption. 4. A smaller percentage of the absorbed dose was present in the livers of the riboflavin-deficient animals.

Animals↗

PubMed2003

Why and how to use radioisotopes in human nutrition research.

Tracer methodology using radioisotopes in human nutrition research has been the object of unjustified limitations in its use. These limitations have encumbered research studies where micronutrient and macronutrient deficiencies are prevalent. Stable isotope methodologies are expensive, including the cost of the isotopes, equipment and its maintenance, and are often fraught with serious pitfalls. We have been developing safe radioisotopic methods to study the metabolism of micronutrients, especially iron and zinc in the developing world. These should allow scientists everywhere to conduct their own research without having to depend on facilities and laboratories in the industrial world, and thus enhance productive collaborative research. All radioisotopic research must be subjected to strict safety criteria, based on scientific evidence of risk, but should not be hampered by unscientific fears. Examples on the use of radio and stable isotopes to study iron and zinc absorptions are given including the radiation exposure and risk calculations.

Costs and Cost Analysis↗

PubMed1995

Isolated rat hepatocytes acquire iron from lactoferrin by endocytosis.

The iron-binding protein lactoferrin (Lf) present in blood is metabolized by the liver. Isolated rat hepatocytes vigorously endocytose bovine Lf via recycling Ca2(+)-dependent binding sites, but the uptake of iron from Lf by hepatocytes has not been examined. In this study, isolated rat hepatocytes were incubated with radiolabelled bovine Lf (125I-Lf, 59Fe-Lf or 125I-59Fe-Lf) at 37 degrees C, then washed at 4 degrees C in the presence of dextran sulphate with either Ca2+ or EGTA to distinguish between total bound and internal radioactivity respectively. Cells internalized 125I-Lf protein and Lf-bound 59Fe at maximal endocytic rates of 1700 and 480 mol.cell-1.s-1 respectively. When Lf was normalized for 59Fe content, these endocytic rates were equivalent and reflected an uptake potential of at least 3400 mol of iron.cell-1.s-1. Cells prebound with 125I-59Fe-Lf to Ca2+(-)dependent sites at 4 degrees C internalized more than 80% of both 125I-Lf protein and Lf-bound 59Fe approx. 6 min after warming to 37 degrees C at similar rates (125I-Lf: k(in) = 0.276 min-1, 59Fe: k(in) = 0.303 min-1). Within 4 h at 37 degrees C, cells had released 25% or less internalized Lf protein in the form of acid-soluble 125I-by-products but retained all the Lf-delivered 59Fe. Hyperosmotic disruption of clathrin-dependent endocytosis blocked the uptake of 125I-Lf and Lf-bound 59Fe. Incubation of cells with 125I-59Fe-Lf and a 100 molar excess of diferric transferrin reduced slightly the endocytosis of 125I-Lf protein and 59Fe accumulation. Treatment of cells with the ferric chelator desferrioxamine did not alter uptake of 125I-Lf protein or Lf-bound 59Fe, but the ferrous chelator bathophenanthroline disulphonate slightly elevated endocytosis of 125I-Lf protein and Lf-bound 59Fe. These findings indicate that Lf does not release its bound iron before endocytosis. It was concluded from this study that hepatocytes take up iron from Lf at high rates by a process that requires endocytosis of Lf-iron complexes.

Animals↗

PubMed1987

Transferrin-receptor interaction and iron uptake by reticulocytes of vertebrate animals--a comparative study.

Transferrin-receptor interactions and iron uptake were studied in eleven different species of vertebrate animals (3 eutherian mammals, 3 marsupials, 2 reptiles and 1 bird, amphibian and bony fish). In the initial experiments it was shown that the uptake of transferrin-bound iron by immature erythroid cells from marsupial and reptilian species occurs by receptor-mediated endocytosis as in other vertebrate animals. Reticulocytes were incubated with 125I-59Fe-labelled transferrins from heterologous species and the results for iron and transferrin uptake compared with those obtained with the homologous protein. Cells from eutherian mammals were able to take up transferrin and iron from other eutherians and from the bob-tailed lizard but not from marsupials and other submammalian species. With marsupials and reptiles a similar specificity was observed, and the marsupial cells could also utilize chicken transferrin but not vice versa. The results were extended by performing competition experiments in which the cells were incubated with radiolabelled homologous transferrin in the presence of increasing concentrations of non-radioactive heterologous transferrins. From the ability of the heterologous proteins to inhibit uptake of the homologous protein relative association constants (Ka1) for the transferrin-receptor interactions could be calculated. These Ka1 values reflected the patterns observed in the first series of experiments. These studies demonstrate that, although specificity exists in transferrin-receptor interactions throughout the range of vertebrate animals, in several instances reactivity between widely divergent species is also observed. Hence, structural similarities have been maintained throughout evolution. Nevertheless, no evidence of interaction between transferrin and its receptor from the two divisions of the Mammalia, the eutherians and the marsupials, was observed.

Animals↗

PubMed1998

Residual 60Co activity in steel samples exposed to the Hiroshima atomic-bomb neutrons.

Residual 60Co radioactivity produced by the neutrons from the Hiroshima atomic bomb has been measured by means of gamma-ray spectrometry for seven steel samples located up to 1,800 m slant range and one control sample obtained at 4.5 km from the hypocenter. After removing the main constituent of iron ions from the steel sample by the solvent extraction method, nickel and cobalt were chemically separated by the ion exchange process. Gamma-ray measurements were performed with a low background well-type germanium detector. Derived specific activities 60Co:Co were compared with previous measurements and with the calculation based on the neutron fluence of current dosimetry system DS86. It has been shown that a systematic discrepancy exists between the measured and calculated activity. The calculated-to-measured ratios for 60Co are consistent with those of 152Eu and 36Cl activity.

Chlorine↗

PubMed1989

The nature of the inhibition of 4,7-dioxobenzothiazole derivatives on mitochondrial ubiquinol-cytochrome c reductase.

To investigate the inhibitory action and binding site of a quinone-like molecule, 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT), a series of 4,7-dioxobenzothiazole derivatives were synthesized and their inhibitory efficiencies studied. Replacing the 6-hydroxyl or 2-hydrogen of UHDBT with a bromo or a methoxy group causes only a slight decrease in inhibitory efficiency, indicating that the 6-hydroxyl or the 2-hydrogen of UHDBT is not a structural requirement for inhibition. 5-Undecyl-6-bromo (or methoxy)-4,7-dioxobenzothiazole shows a pH-dependent inhibition similar to that observed with UHDBT, suggesting that the pH dependence is due to the presence of a dissociable group in the protein complex and not to the deprotonation of the hydroxyl group of the inhibitor. Replacing the 6-hydroxyl group with an azido group causes changes similar to those observed with UHDBT; the inhibition is accompanied by alteration of the epr characteristics of reduced iron-sulfur protein in ubiquinol-cytochrome c reductase. The extent of inhibition is not changed upon illumination of the treated reductase. When the photolyzed, 6-azido-5-(1',2'-[3H] undecyl)-4,7-dioxobenzothiazole [( 3H]6-azido-UDBT)-treated reductase is subjected to organic solvent extraction, no radioactivity is found in the reductase protein. Rather, the radioactivity is located in the phospholipid fraction. A [3H]azido-UDBT-cardiolipin adduct, identified after separation of the phospholipid fraction by high performance liquid chromatography, has 6-azido-UDBT linked to an acyl group, not to the head group of the cardiolipin molecule. These results suggest that inhibition by UHDBT is due to perturbation of specific cardiolipin molecules in ubiquinol-cytochrome c reductase. Since UHDBT and 6-azido-UDBT also inhibit the ubiquinol-cytochrome c reductase activity of delipidated reductase (10% of the original lipid remaining) assayed after reconstitution with ubiquinone and phospholipid, and the [3H]azido-UDBT-cardiolipin adduct is also found in the delipidated reductase, the UHDBT-perturbed cardiolipin molecule is structurally indispensable to reductase and it tightly bound to the reductase protein, most likely the quinone binding proteins.

Electron Transport Complex III↗

PubMed1978

[Nutritional and toxicological impacts of administered inorganic tin for six months in rats (author's transl)].

An experimentation of intoxication by stannous chloride has been realized in the rat. Two groups of animals have been fed ad libitum, during six months, with a diet containing respectively 0,4 and 0,8 g of tin (SnCl2) for 100 g of dry food. By gamma radioactivity measurements (with 113Sn used as a tracer), it results that this metal does not practically clear the digestive barrier. All the treated animals are characterized by a ponderal evolution obviously lower than temoins. At the end of treatment, tin entails a significative diminution of hematocrit, hemoglobin and serous iron, particularly at the highest dose studied. The essential impact remains that tin induces a total irritation of gastro-intestinal tract, proved by histological investigations.

Animals↗

PubMed1986

Oxidative radioiodination damage to human lactoferrin.

Oxidative iodination of human lactoferrin (Lf) as commonly performed by using the chloramine-T, the Iodogen or the lactoperoxidase method produces an unreliable tracer protein because of excessive and heterogeneous polymer formation. Before iodination a minor tetramer fraction may be demonstrable in iron-saturated Lf only. Iodination-induced polymerization of iron-poor as well as iron-saturated Lf occurs independently of the presence or absence of 10 mM-EDTA and the 125I-/Lf molar ratio used for iodination. 125I-Lf polymers are mainly covalently linked, as suggested by the lack of substantial dissociation in SDS/polyacrylamide-gel electrophoresis. Damage to the 125I-Lf monomer may be another consequence of oxidative iodination. This is demonstrated in SDS/polyacrylamide-gel electrophoresis where 50% of the radioactivity of apparently normal monomer (Mr 75,000) is displaced to a lower-Mr region (30,000-67,000) after reduction with dithiothreitol. Non-oxidative iodination by the Bolton-Hunter technique produces an antigenetically stable tracer that is not being subjected to polymerization and monomer degradation as judged by high-performance gel chromatography and SDS/polyacrylamide-gel electrophoresis with and without dithiothreitol treatment. It is concluded that oxidation in itself leads to covalent non-disulphide cross-linking between human Lf molecules and, possibly, to intramolecular peptide-bond breaking becoming unmasked under reducing conditions. In biological experiments with human 125I-Lf this problem should be carefully considered.

Antibody Affinity↗

PubMed1999

Unwanted radioactive sources in the public domain: a historical perspective.

In the 1920's, reports of radium sources entering the public domain in an uncontrolled manner began to appear in the press and in the literature. Additionally, gold jewelry was made from depleted radon gold seeds which, in some cases, resulted in radiation injuries to the persons wearing the jewelry. Such jewelry was made as early as 1910. For many years, radium was distributed and used largely without regulatory oversight for safety. In the 1950's, increasing concern over the radiation hazards associated with the inadequate use, control, and disposal of radium sources resulted in increased regulatory oversight by the States, with significant assistance from the U.S. Public Health Service. In 1958, the U.S. Atomic Energy Commission staff proposed extension of the general license concept to include measuring, gauging, and controlling devices. Since then, more than 1.8 million radioactive devices have been distributed under the general licenses in 10 CFR Part 31.5 and equivalent Agreement State regulations. These devices are typically used with minimal regulatory oversight. In recent years there has been an increasing number of reports of radioactive sources and devices appearing in the public domain as a result of inadequate control and disposal of these items with attendant risk of environmental contamination and radiation exposure. As a result of concerns over these developments there have been calls for increased regulatory oversight of general licensees. It is ironic that the present problems are the result of a program that was established about the time that States were increasing regulatory oversight over radium to address similar problems with radium.

Conservation of Natural Resources↗

PubMed1990

H2O2-mediated cytotoxicity of rat pulmonary endothelial cells. Changes in adenosine triphosphate and purine products and effects of protective interventions.

H2O2-mediated cytotoxicity (as measured by 51Cr-release) of rat pulmonary artery endothelial cells was time-dependent and related to the concentration of H2O2 employed. The cytotoxic effects of H2O2 were, as expected, prevented by catalase and the degree of protection was directly related to its time of addition. Endothelial cells were incubated with [14C]adenosine to achieve intracellular labeling of ATP, after which the cells were exposed to H2O2. Based on analysis of cell extracts by high-performance liquid chromatography, there was a time-dependent loss of intracellular radioactivity and ATP with the simultaneous appearance of purine degradation products including xanthine/hypoxanthine. Approximately 50% of the intracellular ATP was lost after 15 minutes of exposure and up to 80% was lost by 30 minutes. The extracellular fluid of cells exposed to H2O2 contained significant amounts of xanthine/hypoxanthine. The ferric iron chelator deferoxamine provided almost complete protection against H2O2-mediated cytotoxicity. Two inhibitors of xanthine oxidase, allopurinol and oxypurinol, were also protective as was deoxycoformycin, an inhibitor of adenosine deaminase. Remarkably, cells protected by these agents showed the same loss of intracellular ATP as unprotected, H2O2-treated cells. These findings demonstrate the dissociation between ATP loss per se and oxidant injury of endothelial cells. ATP breakdown may be an important event leading to cellular injury in that this results in the formation of substrate for xanthine oxidase.

Adenosine Triphosphate↗