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PubMed2006

[Inductively coupled plasma mass spectrometry. Perspectives in analysis and in biology].

ICP-MS is an instrumental method of multi-elementary qualitative and quantitative analysis. It associates with a mass spectrometer (MS) an ion source composed of a plasma torch fed with inductive coupling with a high frequency electromagnetic generator (ICP), similar to that used as a light source in highly-successful Atomics Emission Spectrometry (AES). ICP-MS can be applied to simultaneous analysis of numerous metallic and metalloid elements (80 or so). Its sensitiveness is all in all far better than that available with previous spectrometric techniques, which nevertheless remain more advantageous for processing certain low atomic mass elements. Thanks to its broad dynamic range, ICP-MS allows quantification of an array of elementary concentrations within a single sample. ICP-MS offers particularly interesting perspectives in geochemistry and metal processing, as well as in biochemistry and food or toxicology and environmental analysis. Implementation is rapid and the technique is suitable for series or continuous analyses, or for analysis of any evolving medium such as effluents from gas or liquid chromatography or from capillary electrophoresis, making it a valuable tool for speciation analyses. Finally it enables non-radioactive isotopic labeling, essential for nutritional studies of trace elements, and sufficiently accurate isotopic dilutions, even with more accessible machines.

Animals↗
PubMed2000

Engineering Deinococcus radiodurans for metal remediation in radioactive mixed waste environments.

We have developed a radiation resistant bacterium for the treatment of mixed radioactive wastes containing ionic mercury. The high cost of remediating radioactive waste sites from nuclear weapons production has stimulated the development of bioremediation strategies using Deinococcus radiodurans, the most radiation resistant organism known. As a frequent constituent of these sites is the highly toxic ionic mercury (Hg) (II), we have generated several D. radiodurans strains expressing the cloned Hg (II) resistance gene (merA) from Escherichia coli strain BL308. We designed four different expression vectors for this purpose, and compared the relative advantages of each. The strains were shown to grow in the presence of both radiation and ionic mercury at concentrations well above those found in radioactive waste sites, and to effectively reduce Hg (II) to the less toxic volatile elemental mercury. We also demonstrated that different gene clusters could be used to engineer D. radiodurans for treatment of mixed radioactive wastes by developing a strain to detoxify both mercury and toluene. These expression systems could provide models to guide future D. radiodurans engineering efforts aimed at integrating several remediation functions into a single host.

Bacterial Proteins↗
PubMed1987

Association of heparan sulfate proteoglycan and laminin with the cytoskeleton in rat liver.

Rats were injected with 35SO4 and after 2 h their livers were removed and used to prepare a detergent-insoluble cytoskeleton fraction. Spectrin, cytokeratins, and actin were major protein components of the isolated cytoskeletons. The cytoskeleton fraction accounted for approximately 14% of the total trichloroacetic acid-insoluble 35SO4 radioactivity incorporated into the liver. The cytoskeleton-associated radioactivity was present in a single species of macromolecule. This molecule was not present to a significant extent in the detergent-soluble fraction containing the cell supernatant and dissolved membrane proteins. Further characterization revealed the cytoskeleton-associated molecule was a heparan sulfate proteoglycan: it was eluted from a Sepharose CL-4B column under denaturing conditions at Kav = 0.4; following mild alkaline hydrolysis the radioactivity was eluted at a Kav = 0.7; when this material was subjected to nitrous acid hydrolysis all of the radioactivity was eluted near the column included volume. The isolated cytoskeletons contained attached nuclei. Pure nuclei isolated without associated cytoskeletal elements contained less than 1% of the total liver trichloroacetic acid-insoluble 35SO4 radioactivity and no detectable heparan sulfate proteoglycan. These results suggested that other matrix proteins might be associated with the liver cytoskeleton. When the subcellular distribution of laminin was monitored by immunostaining proteins transferred to nitrocellulose, laminin was detected exclusively in the cytoskeleton fraction. These results provide evidence for an association between extracellular connective tissue proteins and intracellular structural proteins.

Animals↗
PubMed1994

Cytogenetic conversion in a case of polycythaemia vera treated with interferon-alpha.

Polycythaemia vera is a clonal disorder of the haemopoietic stem cell causing a pathologic expansion of the erythroid and sometimes the megakaryocytic and myeloid elements. In order to avoid the possible mutagenic effects of radioactive phosphorus, alkylating agents and hydroxyurea, since 1988 alpha-IFN has been used for the treatment of PV and has been shown to induce and maintain haematological remission. We describe a 24-year-old PV patient with chromosomal abnormalities who achieved not only a reduction of the proliferation of erythroid elements and reticulin content in the bone marrow, but also a complete cytogenetic remission after IFN treatment.

Adult↗
PubMed1978

Retention of the metabolized trace elements in biological tissues following different drying procedures. I. Antimony, cobalt, iodine, mercury, selenium and zinc in rat tissues.

Loss of Sb, Co, I, Hg, Se and Zn during freeze-drying and oven-drying at 80, 105 and 120 degrees C were studied in rat tissues that contained metabolized radioactive isotopes. No loss was observed for any of the 6 elements on freeze-drying. However, tissue-specific differences were observed in many cases for Hg, Se, I and Sb on oven-drying. A significant loss of Hg was observed in liver even at 80 degrees C, and for brain at 105 degrees C. Se was lost from whole blood, brain, lung, and muscle at 120 degrees C. Sb was lost from whole blood at 105 degrees C, but from brain, kidney, lung and spleen at 120 degrees C. Iodine was also lost from whole blood, kidney, blood serum, erythrocytes, brain, lung and muscle at 120 degrees C. Although the losses were statistically significant, they remained in most cases between 2 and 10%, with the exception of Hg at 120 degrees C, where the losses in some of the tissues were unpredictable. For urine, freeze-drying and oven-drying at 80 degrees C was found to be relatively safe for Hg and I. At 105 degrees C and above, serious loss of Hg was observed. In this experiment, the elements Zn, Co, Sb and Se were no studied for urine.

Animals↗
PubMed2001

Radioactive and conventional pollutants accumulated by edible mushrooms (Boletus sp.) are useful indicators of species origin.

Concentrations of artificial radionuclides and trace elements in Boletus samples collected in different areas of the world were detected, respectively, by gamma spectrometry and neutron activation analysis. The particular commercial value of Boletus edulis, B. aestivalis, and B. pinophilus from the Taro Valley (Parma, Italy) has often stimulated local factories to trade edible Boletus imported from several areas of the world as the real Taro Valley mushroom. Starting from this evidence, the calculation of the Chernobyl radioactive contamination in the mushrooms coupled with the presence of particular stable elements and their concentration factors has been demonstrated to be a potential useful tool for identifying the real origin of the samples. In fact, major differences in the radiocesium activity levels and trace element presence were observed even in mushrooms collected in nearby valleys. The radiometric data are supported by the statistical analysis. In particular, both the principal component analysis and the concentration distribution along a regression line support the idea of two different clusters: one referred to the "king boletus" of the Taro Valley and another one to the other conspecific samples from different ecosystems.

Agaricales↗
PubMed1970

Cardiovascular mortality in relation to radioactivity and hardness of local water supplies in the USA.

Several authors have reported an inverse correlation between death rates from cardiovascular diseases and local water hardness, but the significance of such a relationship is still debated. To investigate further this relationship, another indicator of water quality was used, namely, the alpha-radioactivity level of raw river waters in the USA. This indicator also showed a negative correlation with cardiovascular death rates, particularly from hypertensive heart disease, which was consistent whether the data were analysed by state, by river basin, by county, or by community. The fact that the negative relationship holds true for raw river waters indicates that broader environmental and geochemical factors may be involved. The effects of trace elements present in the soil and in the water on man's mineral balance, and eventually on the cardiocirculatory function, are discussed.

Cardiovascular Diseases↗
PubMed2000

Determination of biokinetic parameters for ingestion of radionuclides of zirconium in animals using stable tracers.

Exposure to the radioactive isotope 95Zr, as in nuclear accidents, and to stable zirconium, due to its use in industry, has increased the interest in the biokinetics of this element. Information has been derived mainly from tests performed on animals by means of radioactive tracers. Due to the fact that extrapolation from animals to humans is always open to question, there is an increasing need of a methodology which allows data to be obtained directly from humans. The use of stable tracers, being ethically justifiable, is a powerful tool for providing this information. As two tracers of the same element must be utilized in order to evaluate gut absorption, an analytical technique which is capable of distinguishing and measuring simultaneously different isotopes of zirconium in biological samples is required. Preliminary tests on laboratory animals were performed in order to assess the feasibility of the double tracer technique combined with proton activation analysis.

Animals↗
PubMed2003

Kinetic partitioning of Co, Mn, Cs, Fe, Ag, Zn and Cd in fresh waters (Loire) mixed with brackish waters (Loire estuary): experimental and modelling approaches.

To simulate the behavior of radionuclides along a salinity gradient, in vitro sorption and desorption kinetics of Co, Mn, Cs, Fe, Ag, Zn and Cd were studied in Loire river water and the macrotidal Loire estuarine water over two different seasons. Partitioning between the dissolved phase and suspended solids were followed up over 100 h after adding radioactive tracers to freshly collected freshwater (sorption stage); this stage was followed by desorption in fresh and estuarine waters. A kinetic model describing the interactions between trace metals and particles under a salinity gradient was developed and calibrated. Among parameters and/or processes that control the fate and behavior of contaminated particles during their transfer in estuarine systems, this study shows that the speciation of trace metals is controlled by: (i) the chemical water composition: for all the elements except for Fe, desorption increased with salinity; however, the amplitude of such an effect strongly depended on the element and/or on the composition of the particulate phase (and consequently on the season); (ii) the possibility for a given element to form (or not) stable surface particle moieties such as oxides or inner-sphere complexes; (iii) the distribution of a given element among different types of sites characterised by different binding forces that can lead (or not) to re-adsorption processes after mixing of contaminated particles with uncontaminated water. Our model enabled the quantification of the contribution and the characteristic time of reactions that took place over short and long periods on the global partitioning between particulate and dissolved phases during sorption and desorption and to determine the extent to which these reactions were modified by the salinity.

Adsorption↗
PubMed1977

The pharmacokinetics of [3H]-vincristine in man.

The pharmacokinetics, metabolism, and excretion of aromatically labeled tritiated vincristine (VCR) was examined in 4 patients. Clearance of radioactivity from the blood was triphasic with half-life t1/2 values of 0.85, 7.4, and 164 min. The initial phases probably represent distribution and binding to formed blood elements which exceeded 50% of the administered dose by 20 min. Excretion of radioactivity was principally fecal, with 33% recovered in the feces by 24 hr and 69% by 72 hr. Considerably less radioactivity (12%) was excreted in the urine over the 72-hr period. Approximately 40% of fecally excreted and 46% of urinary excreted radiolabel represented metabolites, which suggests that at least 34% of the VCR dose was excreted as metabolies. Plasma metabolites represented from less than 1% to 30% or more of radioactivity in plasma. Ultraviolet spectral analysis of all metabolites revealed preservation of the intact VCR dimer, which suggests that metabolism involves alteration of side groups.

Adult↗
PubMed1980

A simple method for measuring zinc absorption in man using a short-lived isotope (69mZn).

Using a short-lived isotope of zinc (69mZn) with a half-life of 13.9 hr, we have developed a simple test of zinc absorption. After an oral dose of isotope (50 muCi) with 2 mg of elemental zinc a plasma appearance curve was constructed from radioactivity determined in blood samples taken sequentially over 8 hr. Two week later an iv dose of isotope (25 muCi) was administered and a plasma disappearance curve was constructed. Absorption was calculated by computer analysis of appearance and disappearance curves using a deconvolution programme. Mean absorption in five normal subjects was 61% (range 41 to 79%). In three subjects given food with, or 1 hr before the isotope, absorption was delayed and reduced to less than 20% of the oral dose at 8 hr. This test of zinc absorption is simple to perform and, because the isotope has a short half-life, has the advantage of subjecting patients to only limited radiation.

Absorption↗
PubMed1976

[Initial results on the use of C11 recoil-labelled amino acids in the animal experiment].

Extracorporeal measurement of incorporated radioactive organic compounds needs labelling with gamma emitters. The elements of organic compounds have only very short-lived gamma-emitting isotopes. (Organic compounds, therefore, up to now were labelled by more or less stable chemical coupling with gamma-emitting isotopes of the halogens or of certain metals as, for instance, chromium-51). The use of the C-11 isotope with a half-life period of about 20 min, emitting gamma radiation due to the annihilation radiation of its positrons, is very problematical, because these very short-lived nuclides can be used only at the place of their production by nuclear engineering. But especially these nuclides are very interesting just because of their short half-life period, the radiation load being lessened thereby and, in addition, the organic compound remaining chemically unchanged. Utilizing the (gamma, n) reaction, we have succeeded in labelling organic molecules in solid state directly within the electron beam due to the retarding of particles from a linear electron accelerator, and the absolute as well as the specific yield was satisfying. Till now, we have tested almost exceptionally amino-acids; during experimentation with rats, an example of the practicable utilization in nuclear medicine was set by means of the amino-acid methionine. This was confirmed by results of comparative studies using C-14 and Se-75 labelled methionine (Se-methionine respectively).

Amino Acids↗
PubMed1996

Instrumental neutron activation analysis of essential and toxic elements in child and adolescent diets in the Chernobyl disaster territories of the Kaluga Region.

The main etiologic factor of various diseases, syndromes and pathologic conditions is an excess, deficiency or imbalance of trace element intake into the human body. Children seem to be the most sensitive to each change of trace element homeostasis. An inadequate essential trace element intake may result in an undesirable consequence that can apparently multiply against a background of additional unfavourable environmental influence such as high levels of radiation, organic and inorganic toxins, etc. Thus, the quality control of children's diets assumes urgent importance within the regions covered by the Chernobyl disaster. Instrumental neutron activation analysis was used to estimate contents of Ag, Br, Ca, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se, Sr, and Zn in the diets of children and adolescents. Diets were chosen from day care centre, boarding school and technical college cafeterias situated within the south and south west territories of the Kaluga Region, where radionuclide contamination ranges up to 15 Ci/km2. Ca and Zn deficiencies were found in the diets of children and adolescents aged 7-18. The Ca intake is only 212 mg/day, 5 times lower than that in developed countries. The Zn intake is 6.8 mg/day, 2 times lower than the level recommended by the WHO.

Adolescent↗
PubMed2005

Accumulation and release of 241Am by a macrophyte of the Yenisei River (Elodea canadensis).

The source of radioactive contamination of the Yenisei River floodplain, including contamination with transuranic elements, is the Mining-and-Chemical Combine of the Russian Ministry of Atomic Energy, which has for many years been producing weapons-grade plutonium. Transuranic elements have been detected not only in the soil and sediment of the river but also in the biomass of aquatic plants. This work is an investigation of accumulation and release of 241Am by a submerged macrophyte of the Yenisei River (Elodea canadensis) in laboratory experiments. In 2000-2003, laboratory experiments were carried out with biomass of E. canadensis Mich. and filtered river water. The samples were collected from the Yenisei River upstream of the discharge of the Combine's radioactive effluent. The experiments showed that 241Am is accumulated by Elodea biomass: the activity concentration of 241Am can reach 3280+/-240 Bq/g, with the concentration factor for 241Am 16 600+/-2200l/kg. Results of chemical fractionation have proved that in the course of 241Am accumulation by Elodea biomass, 241Am tightly bound to biomass increases from 11% to 27% of the total 241Am in the biomass. Release of 241Am from the decaying Elodea biomass has been evaluated experimentally. By the end of the experiment (lasting up to 127 days), the Elodea plants had lost up to 65% of their initial 241Am activity and the rate of 241Am release into the water environment reached 23 Bq/day.

Adsorption↗