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Serum vanadium levels have been measured by neutron activation analysis. They are higher (3.10 +/- 1.38 ng/mL) in patients suffering depressive illness than in normal subjects (0.67 +/- 0.32 ng/mL).

Various deep, compact, sedimentary formations have been studied in recent years as potential host rock for a repository for high-level, long-lived radioactive waste. Considering that microbial activities may influence radionuclide chemistry and migration in such environments, we investigated the potential presence of microorganisms in the Opalinus Clay formation, from unperturbed sediment samples (i.e., not affected by gallery excavation and borehole drilling) recovered under aseptic conditions in the Mont Terri Underground Rock Laboratory (Switzerland). A combination of molecular biology techniques and a cultivation-based approach suggested the presence of a few sparse autochthonous microbial cells in the Opalinus Clay. For the first time, ribosomal RNA (rRNA) genes were sequenced from enrichment cultures from such samples. The results suggested that at least two of the bacterial strains isolated were likely unknown species of the Sphingomonas and Alicyclobacillus genera, as their fully-sequenced 16S-rRN...

s Amongst all the fission fragments, actinides and activation products coming from the nuclear energy processes, a dozen radionuclides are a hazard for Man and environment, due to their half-life and toxicity. For the last 3.5–4 billion years (Ga), microorganisms have been present on Earth in all sorts of surroundings, even the most hostile ones, characterized by extreme pH, temperature and/or radioactivity. To grow and multiply, they developed enzymatically induced oxido-reduction reactions by coupling reduction of metals/metalloids with oxidation of organic matter, which, in turn, may change soluble forms of radionuclides or stable elements into non-soluble forms. When this happens, microorganisms contribute to fix the radionuclides and prevent dissemination.

It is shown for the first time that haloalkaliphilic bacteria, isolated from soda-lake environments were capable of reducing Tc(VII)O(4) (-) to the Tc(V), Tc(IV) and Tc(III) at pH 10 in carbonate medium, whereas no reduction took place without bacteria or in the presence of dead biomass. After 34 h of incubation, 55% remained as Tc(VII), 36% was found as Tc(IV) and 8% as Tc(V) and after 2 months 80% of the technetium was reduced. Technetium has a toxic effect on bacteria. Reduction of TcO(4) (-) was drastically decreased at concentration above 1.5 mM. The microbial reduction has been suggested as a potential mechanism for the removal of Tc from contaminated environments or waste streams.

The ability of bacteria to reduce pertechnetate in alkaline conditions was investigated using halophilic bacteria isolated from soda-lakes environments. Anaerobic halophilic bacteria were able to reduce as much as 0.25 mM pertechnetate, whereas no reduction took place without bacteria or in the presence of heat-killed bacteria. The results obtained showed reduction of Tc(VII)O4 − to the Tc(V) and Tc(IV) at pH 10 in the carbonate-bicarbonate medium. About 57% of the total technetium was determined to be Tc(IV), 1–3% as a Tc(V) and 17–20% as a Tc(VII) after 1–3 days of incubation with bacteria. The microbial reduction of Tc(VII) in alkaline conditions has been suggested as a potential mechanism for the removal of Tc from contaminated environments or waste streams.

A laboratory study is made of Tc, Np, and Pu accumulation by natural and sterilized silts collected from two typical eutrophic and dystrophic lakes of the Moscow oblast. After a short inductive period (1-3 days), the rate of Tc uptake by the eutrophic lake silt is about twice that by the dystrophic lake silt (at a dry solid to liquid phase ratio of 0.033 g ml-1). The rate is only slightly temperature-dependent, being practically constant (at a level of about 3% per day) under certain conditions. The distribution coefficients after a month of contact were found to be 1700±50 and 56±5 ml g-1 for the eutrophic and dystrophic lake silts, respectively. Sulfate and nitrate have an inhibiting effect on the Tc uptake. Efficient desorption of Tc from bottom sediments can be realized only in the presence of an oxidant (H2O2), suggesting the reductive mechanism of Tc sorption on silts, complicated by either complexation with microorganism cell components or by intracellular deposition.

A high resolution inductively coupled plasma mass spectrometric (HR-ICP-MS) method for the determination of plutonium isotopes, Am and the 240Pu/239Pu isotope ratio utilising modification of Pu-02-RC Plutonium in Soil Samples, Pu-03-RC Plutonium in Soil Residue—Total Dissolution Method, Pu-11-RC Plutonium Purification—Ion Exchange Technique, Pu-12-RC Plutonium and/or Americium in Soil or Sediments, HASL-300 was developed. Total plutonium concentrations (239+240Pu) measured in environmental samples by this HR-ICP-MS method were in good agreement with recommended data obtained from a-spectrometry. It was achieved the decreasing of the time to analyze the samples over than 33%.

N-myc oncogene amplification is one of the most established prognostic factors in neuroblastoma (NB), a young children solid tumor. Amounts of ferritin, an iron storage protein, are abnormally increased in serum of patients with advanced stage disease. N-myc amplified NB cells can synthesize zinc metalloenzymes allowing tumor invasion and metastases formation. The aim of this study was to find a relationship between N-myc amplification and trace metals in human neuroblasts. Coupling PIXE and RBS techniques, nuclear microprobe allowed to analyze elemental distributions and to determine trace metal concentrations within cultured neuroblasts characterized by various degrees of N-myc amplification. They were compared to trace metal distributions and concentrations in tumor xenograft models of human NB, after injection of cells from the same lines in athymic nude mice. Our data allowed to establish a relation between trace metal contents and mechanisms of NB oncogenesis, amplified cell lines representing more aggressive phenotypes of the disease. They should be confirmed by analysis of cultured neuroblasts and tumors issued from a non-amplified cell line transfected with the N-myc oncogene.

Iron is an essential micronutrient required for cell division and growth. Incorporation of iron into cells is achieved by endocytosis of transferrin. Then, iron may be stored in ferritin and hemosiderin. Increased intracellular iron concentrations may promote malignant cell growth. Patients with advanced-stage neuroblastoma (NB) show abnormally high levels of serum ferritin, very likely synthesized and secreted by the tumor in vivo and consistent with a frequent accumulation of iron in ferritin in NB tumor tissues. In a previous study, we showed that there is no iron accumulation in cultured neuroblasts, and intracellular iron concentrations proved to be especially low. Bio-Normalizer® (BioN) is a nutritional supplement sold to be an anti-oxidant and metal-chelator. In the present study, we tested cell viability and measured iron concentrations in neuroblasts treated or not with BioN. We found that BioN, probably thanks to papain, presents an anti-proliferative effect on NB cultured cells. Besides, preliminary results tend to prove that this natural anti-oxidant and iron-chelator could present interesting effects on trace metal concentrations in neuroblasts. Such a compound may be useful in treatment of this pathology.

The retina as well as other tissues needs iron to survive, but modifications in iron metabolism have also been suggested to contribute to cerebral neurodegenerative diseases. Our study was intended to investigate iron distribution in the retina of normal rats and Royal College of Surgeons (RCS) rats affected by hereditary degeneration of the photoreceptors at different developmental stages (35, 45 and 55 days after birth). Iron (Fe) distribution was determined by proton induced X-ray emission (PIXE) microanalysis on retinal sections and compared to other tissues (cornea, liver, spleen) and to other elements (Cu, Zn, Ca). Elemental concentrations were determined in different retinal layers especially the photoreceptors, which are progressively altered and disappear in the RCS rats. Iron is unevenly distributed throughout the rat retina. The highest concentration is observed in the choroid and the retinal pigmented epithelium and in the inner segments of photoreceptors. Iron content is lower in the outer segments but still significant. It increases during both the development and the disease at the level of the segments. This last localised iron increase can result in an overproduction of free radicals and be correlated with the photoreceptor cell loss. The distributions of other elements (Cu, Zn, Ca) revealed interesting temporal progressions.

N- myc oncogene amplification is a powerful predictor of aggressive behavior of neuroblastoma (NB), the most common solid tumor of the early childhood. Since N- myc overexpression – subsequent to amplification – determines a phenotype of invasiveness and metastatic spreading, it is assumed that N- myc amplified neuroblasts synthesize zinc metalloenzymes leading to tumor invasion and formation of metastases. In order to test a possible relation between N- myc oncogene amplification and trace metal contents in human NB cells, Fe, Cu and Zn concentrations have been measured by nuclear microprobe analysis in three human neuroblastoma cell lines with various degrees of N- myc amplification. Elemental determinations show uniform distribution of trace metals within the cells, but variations of intracellular trace metal concentrations with respect to the degree of N- myc amplification are highly dependent on the nature of the element. Zinc concentration is higher in both N- myc amplified cell lines (IMR-32 and IGR-N-91) than in the non-amplified cells (SK–N–SH). In contrast, intracellular iron content is particularly low in N- myc amplified cell lines. Moreover, copper concentrations showed an increase with the degree of N- myc amplification. These results indicate that a relationship exists between intracellular trace metals and N- myc oncogene amplification. They further suggest that trace metals very probably play a determinant role in mechanisms of the neuroblastoma invasiveness.

Several types of hereditary retinal degeneration with progressive alteration of photoreceptors exist in men and animals. Recent immunohistochemical results have shown strong degradation of transferrin, the protein responsible for iron transport, in retinas of rats with hereditary retinal degeneration. Freeze-dried thin sections of rat retinas from different stages of the disease, and respective coeval control sections, have been analyzed using nuclear microprobe. In this first part of the study, the rat retinas at post-natal stages of 35 and 45 days have been analyzed. The sample preparation and the post-irradiation staining to determine precisely the retinal layers involved are described. Preliminary results of element distributions (K, Ca, Fe) in the rat retina layers are discussed. A very high content of calcium in the choriocapillaris of dystrophic rat retinas was observed. Preliminary results on iron distribution in the rat retina layers are presented.

The effect of extracellular adhesion factors, and of distinct culture substrata, on trace element content of epithelial cancer cells was investigated using nuclear microprobe analysis. Essential trace metal concentrations in human carcinoma cells cultured either onto tissue culture plastic dishes, onto microanalysis supports made of thin Formvar surfaces coated or not with gelatin gel, or onto polycarbonate films, were compared. Abnormally high copper concentrations were noticed specifically in cisplatin-resistant epithelial cancer cells cultured onto Formvar or polycarbonate surfaces with or without reconstituted extracellular matrix. Manganese, iron and zinc concentrations remained unchanged in these cells. These results indicate that (1) metal uptake of cells cultured onto substrata used for X-ray microanalysis can be different to that of cells cultured onto usual plastic dishes, (2) cisplatin-resistant epithelial cancer cells specifically accumulate copper when cultured onto thin Formvar or polycarbonate films, and could be used as in vitro models for copper overload studies.

Resume Le deces de patients VIH-positifs de cause cardiaque n'est pas exceptionnel. L'etiologie des myocardiopathies dilatees associees au sida est souvent inconnue, meme a l'autopsie. Nous rapportons une observation associee a une carence majeure en selenium. Ce patient, seropositif pour le VIH depuis 4 ans presente une pneumocystose pulmonaire puis une cryptococcose neuromeningee. Deux mois plus tard il est hospitalise pour une pancreatite alors qu'il est en etat de grande denutrition. Il presente alors un etat de defaillance cardiaque globale entrainant le deces. Aucun agent pathogene n'est mis en evidence dans le myocarde a la necropsie, mais le taux plasmatique de selenium est effondre a 24 μg/L. Le deficit en selenium a ete associe a une myocardiopathie dilatee en dehors du sida (maladie de Keshan). Les patients VIH-positifs voient une baisse precoce de leur taux plasmatique de selenium, celui-ci pouvant etre effondre chez des patients denutris. La carence en selenium pourrait expliquer un certain nombre des myocardiopathies dilatees associees au sida, et la supplementation en selenium pourrait etre utile chez ces patients.

Some transition metals play important regulatory roles in gene expression. The disturbance of their cellular levels could be involved in oncogene expression and tumorigenesis. Nuclear Microprobe Analysis (NMPA) was used to measure cellular trace metal levels (Mn, Fe, Cu, Zn) in two human neuroblastoma cell lines characterized by distinct genotypes. In this paper, a specific protocol established for sample preparation of neuronal cultured cells is described. Trace metal concentrations in SK-N-SH and IGR-N-91 cells exhibiting respectively a single copy, and 60 copies, of the N-myc oncogene are reported. A brief discussion on experiment design for NMPA of trace metal functions in gene expression is also presented.

BACKGROUND Peripartum cardiomyopathy is a frequent condition of unknown origin in Sahelian West Africa. OBJECTIVE To identify the nutritional and trace-elements status, plasma concentrations of albumin, pre-albumin (trans-thyretin), retinol binding protein, copper, selenium and zinc were assayed in 35 African women living in a Sahelian area, hospitalized in the Hopital national, Niamey (Republic of Niger) with peripartum cardiac failure due to peripartum cardiomyopathy. METHODS Plasma albumin was assayed by an automatic method; pre-albumin and retinol binding protein by radial immunodiffusion (Mancini's method); and plasma copper, selenium and zinc by neutron activation and particle-induced X-ray emission. The results were compared with those for a control group of African women living under the same conditions but without peripartum cardiac failure. RESULTS Plasma albumin and pre-albumin were lower in patients with peripartum cardiomyopathy than they were in controls (P < 0.001). For retinol binding protein, the difference was not statistically significant. The plasma concentrations of selenium and zinc were lower in patients than they were in controls (48 +/- 25 versus 77 +/- 16 ng/ml and 0.90 +/- 0.21 versus 1.17 +/- 0.25 micrograms/ml, respectively, P < 0.001) whereas that of copper was higher (2.03 +/- 0.37 versus 1.23 +/- 0.20 micrograms/ml, P < 0.001). The mean zinc: copper ratio was lower in patients than it was in controls (0.44 versus 0.95). CONCLUSION Such differences may be aetiological factors or biological consequences of the peripartum cardiac failure due to cardiomyopathy. Nutritional abnormalities may play a role in the pathophysiology of the disease.

To investigate the effects of selenium or beta-carotene supplementation in human immunodeficiency virus (HIV)-infected patients, who are known to have deficiencies of selenium and vitamin A, we evaluated the blood enzymatic antioxidant system, including superoxide dismutase (SOD), selenodependent glutathione peroxidase (GPX), and catalase (Cat); glutathione (GSH) status; and plasma selenium concentration. The placebo group consisted of 18 HIV-infected patients with no supplementation, the selenium group was composed of 14 patients receiving oral selenium treatment, and the beta-carotene group comprised 13 patients receiving oral beta-carotene supplementation. All groups were studied for 1 y. At the beginning of the study, a significantly higher SOD activity (P < 0.001) was observed in all HIV-infected patients compared with uninfected control subjects, and GPX activity at baseline was higher in the placebo (P < 0.004) and selenium (P < 0.014) groups than in the control subjects. These higher enzyme activities could be related to an increased synthesis of these enzymes in erythrocyte precursors under oxidative stress. Moreover, we observed significantly lower GSH values in all HIV-infected patients than in control subjects at the beginning of the study (P < 0.001). After selenium or beta-carotene supplementation, no significant difference was observed for SOD activity compared with baseline. On the contrary, GPX activity increased significantly after selenium treatment (P < 0.04 between 3 and 6 mo), whereas a slight increase was found after beta-carotene treatment. Similarly, a significant increase in GSH values was observed at 12 mo compared with baseline both after selenium supplementation (P < 0.001) and beta-carotene supplementation (P < 0.01). Because GPX and GSH play an important role in the natural enzymatic defense system in detoxifying hydrogen peroxide in water, selenium supplementation could be of great interest in protecting cells against oxidative stress. The lower efficiency of beta-carotene could be attributed to the seriousness of the pathology at the time of recruitment into the beta-carotene group.

Macro-and Micro-PIXE analysis were applied to study the mechanisms of cellular resistance to cisplatin, a chemotherapeutic agent, widely used nowadays for the treatment of ovarian cancer. Two cultured cell lines, a cisplatin-sensitive and a resistant one, were compared for their trace elements content and platinum accumulation following in vitro exposure to the drug. Bulk analysis revealed significant differences in copper and iron content between the two lines. Subsequent individual cell microanalysis permitted us to characterize the response of the different morphological cell types of the resistant line. This study showed that the metabolism of some trace metals in cisplatin-resistant cells could be affected but the exact relationship with the resistant phenotype remains to be determined. From a technical point of view, this experiment demonstrated that an accurate measurement of trace elements could be derived from nuclear microprobe analysis of individual cell.

The epithelial cells of the human amniotic membrane have been extensively studied by electrophysiologists with the aim of elucidating the mechanisms of transmembrane ionic transfers. In order to provide complementary information about this model, nuclear microanalysis was performed using the CENBG ion microbeam. Quantitative mapping of the human amnion was carried out and the distributions of most mono- and divalent ions involved in cellular pathways (Na+, Mg2+, Cl−, Ca2+) were determined. The ionic cellular content was also compared, before and after incubation in a Hanks' physiological fluid and the resultant ions transfers were determined. The aim of this paper is to expose the advances of this experimental model, more particularly after the development of simulation programs which improved the accuracy of PIXE analysis in the measurement of low energy X-rays emitters. Statistically significant results can now be extracted and can be explained taking into account the results of previous electrophysiological experiments.

The effect of taurine on the Na(+), K(+), Cl(-) concentration and distribution in epithelial and compact layers of the human amniotic membrane had been investigated using the Bordeaux nuclear microprobe. Particle induced X-ray emission and Rutherford backscattering spectrometry techniques had been used to provice quantitative measurements. In physiological medium, the monovalent ions concentrations were identical in epithelial and compact layers. The addition of taurine in Hanks' physiological fluid had no effect on Na(+) concentration, but decreased K(+) and Cl(-) concentration in both layers. The quantitative results were related to electrophysiological observations on the effect of taurine on ionic exchanges through channels and paracellular pathways.

The micro-PIXE technique has been regularly carried out for more than two years to provide elemental distributions in human cells. Using this technique in the framework of cellular biology, two research axes have been developed: the cellular pharmacology f chemotherapeutic agents and the physiology of ionic cellular exchanges. These studies are based upon in vitro experimental models of human cells, either under the form of isolated cultured cells or as part of well-structured tissues. The aim of this paper is to present the experimental procedures and methodological aspects of cellular and subcellular quantitative mapping. Cell processing, identification of intracellular structures, quantitatives results and beam damage will be discussed and illustrated by examples issuing from the above-mentioned studies.

A new dietary factor, the glucose tolerance factor (GTF), was reported in 1957 that improved impaired glucose tolerance in rats. Most studies on GTF have used brewer's yeast as the starting material, and it has been postulated that the active material is a low-mol wt organic complex containing Cr3+. It seemed thus important to isolate an active GTF from chromium-rich yeast (228 ppm Cr) obtained by incubation with chromium and to compare each fraction with corresponding ones from untreated yeast (0.48 ppm Cr). We developed an isolation and purification procedure by fractionation of yeast extract on an anion and cation exchange resin, and tested the GTF activity (glucose oxidation) on rat adipocytes. PIXE (proton-induced X-ray emission) was used to measure the chromium content of the individual fraction. Individual fractions with GTF activity did not differ between Cr-rich and Cr-deficient yeast, and there was no relationship between Cr content and GTF activity. This does not support the hypothesis that chromium is an obligatory constituent of the GTF, assuming that GTF is a unique substance.

International audience; In this study, we report a rapid sonochemical synthesis of monodisperse nonaggregated Fe3O4@SiO2 magnetic nanoparticles (NPs). We found that coprecipitation of Fe(II) and Fe(III) in aqueous solutions under the effect of power ultrasound yields smaller Fe3O4 NPs with a narrow size distribution (4−8 nm) compared to the silent reaction. Moreover, the coating of Fe3O4 NPs with silica using an alkaline hydrolysis of tetraethyl orthosilicate in ethanol−water mixture is accelerated many-fold in the presence of a 20 kHz ultrasonic field. The thickness of the silica shell can be easily controlled in the range of several nanometers during sonication. Mössbauer spectra revealed that nonsuperparamagnetic behavior of obtained core−shell NPs is mostly related to the dipole−dipole interactions of magnetic cores and not to the particle size effect. Core−shell Fe3O4@SiO2 NPs prepared with sonochemistry exhibit a higher magnetization value than that for NPs obtained under silent conditions owing to better control of the deposited silica quantities as well as to the high speed of sonochemical coating, which prevents the magnetite from oxidizing.

The sorption of selenite ions onto Fe3O4 and Fe/Fe3C nanoparticles (NPs) was studied in aqueous solutions under anoxic conditions using gamma spectrometry and X-ray absorption spectrometry (XAS) techniques. This is the first study related to the remedial applications of Fe/Fe3C NPs. FesO4 NPs have been prepared by conventional coprecipitation of Fe(II) and Fe(III) in basic solutions. Stable Fe/Fe3C NPs have been prepared by Fe(CO)5 sonicating in diphenylmethane solutions and subsequently annealing the as-prepared product. Kinetic study demonstrated that Se(IV) sorption is extremely rapid: the equilibrium is reached in approximately 10 and 30 min for Fe3O4 and Fe/Fe3C NPs, respectively, at pH = 4.9-5.1 in solutions of 0.1 M NaCl. The distribution coefficients are also very high for both kinds of NPs (Kd3000). Increasing the pH to 10.3 or adsorption of organic ligands, like L-lysine or dodecanoate, at the surface of NPs causes the decrease in Kd values. However, even in these cases Kd values exceed 150. Magnetic NPs loaded with selenium can be easily and completely removed from solution with a 0.4 T permanent magnet. XAS study revealed the absence of Se(IV) reduction during the sorption onto Fe3O4 NPs in the pH range of 4.8-8.0. By contrast, the removal of Se(IV) with Fe/Fe3C NPs in anaerobic conditions occurs via Se(IV) reduction to Se(-II) and subsequent formation of iron selenide at the particle surface. Thus, the Fe/Fe3C NPs are superior to Fe3O4 NPs due to their ability to immobilize rapidly and irreversibly Se(IV) via reductive mechanism. Presumably these particles could be also effective for the removal of other contaminants such as hexavalent chromium, actinides, technetium, and toxic organic compounds.

Recently published results of the cooperative studies executed by the Institute of Physical Chemistry and Electrochemistry of Russian Academy of Sciences (IPCE RAS), Research Center Vallée du Rhone (CEA, France), Institute of Nuclear Physics Orsay and University Bordeaux I [Centre Nationale de Recherches Scientifiques (CNRS), France] are reviewed. The review includes data obtained for the first time on the electrochemical properties and anodic dissolution of uranium monocarbide considered among possible bases of the fuel for the reactors of the IVth generation. The results of the investigations in the field of the synthesis of tetraalkyl ammonium pertechnetates, their physicochemical properties and thermal decomposition with formation of Tc metal and Tc monocarbide are summarized. The electrochemical reactions with participation of Tc ions in various oxidation states and their application in the nuclear fuel cycle are described. The behavior of technetium in natural waters near the locations of the radwastes long-term storage and in the areas surrounding nuclear power plants in RF and France was studied.

Opalinus Clay is a candidate host rock for a high-level radioactive waste repository in Switzerland. Microbial metabolism and its by-products could affect the physical and (geo)chemical conditions in such a repository. This study investigated the occurrence of indigenous microbes, their community size and-structure in an Opalinus Clay core from the Mont Terri Underground Research Laboratory, Switzerland, drilled with aseptic techniques. Core sub-samples were distributed to five laboratories, where they were analysed with microscopy, culture-and molecular biology techniques. Evidence supporting a viable microbial community in Opalinus Clay included: five positive culture results (including for sulphate-reducing bacteria, SRB) out of 20 culture attempts; extraction of 64 ng phospholipid fatty acids (PLFA) per g clay, suggesting the presence of viable cells; detection of PLFA biomarkers for anaerobic Gram-negative bacteria and SRB; and the presence of sufficient nutrients to support growth of indigenous and ...

Washed cell suspensions of the anaerobic hyperthermophilic archaea Thermococcus pacificus and Thermoproteus uzoniensis and the anaerobic thermophilic gram-positive bacteria Thermoterrabacterium ferrireducens and Tepidibacter thalassicus reduced technetium [(99)Tc(VII)], supplied as soluble pertechnetate with molecular hydrogen as an electron donor, forming highly insoluble Tc(IV)-containing grayish-black precipitate. Apart from molecular hydrogen, T. ferrireducens reduced Tc(VII) with lactate, glycerol, and yeast extract as electron donors, and T. thalassicus reduced it with peptone. Scanning electron microscopy and X-ray microanalysis of cell suspensions of T. ferrireducens showed the presence of Tc-containing particles attached to the surfaces of non-lysed cells. This is the first report on the reduction in Tc(VII) by thermophilic microorganisms of the domain Bacteria and by archaea of the phylum Euryarchaeota.

The sorption of technetium by powdered and polished mineral stibnite Sb2S3 has been investigated in simulated and natural underground waters from the Meuse/Haute–Marne region (France). The sorption by powdered stibnite has been found to be complete under both aerobic and anaerobic conditions in batch experiments. The sorption rate is higher in the absence of oxygen than under aerobic condition. Increasing the temperature from 30 °C to 60 °C results in a rise of the sorption rate by 9.1 and 27 times under anaerobic and aerobic conditions, respectively. The observed differences in sorption kinetics in the presence and in absence of oxygen are explained by the interaction of oxygen with sulfide ion in aerobic conditions and by the reduction of technetium(VII) by iron(II) and by other impurities present in natural water and in the mineral, and by the subsequent sorption of Tc(IV) on stibnite under anaerobic conditions. The sorption on a polished mineral surface resulted in the formation of a technetium film, probably Tc2S7, with a thickness of 1−3 μg Tc/cm2 at pH 3−6 and 4−12 μg Tc/cm2 at 9−12. The simultaneous formation of stibnite colloids with adsorbed technetium occurs at pH 9−12. The study of the technetium film on the mineral by proton induced X-ray emission analysis showed it to be at least one order of magnitude thinner on the SiO2 impurities than on the main Sb2S3 component and the iron impurities.

Peripartum heart failure due to unexplained dilated cardiomyopathy is a common disorder as Savannak-Sahelian Africa. One of the many suspected risk factors identified is selenium deficiency. The purpose of this study was to measure plasma selenium levels in patients with peripartum heart failure due to cardiomyopathy in Bamako, Republic of Mali and compare data with healthy Sahalian women with the same obstetrical status. Plasma selenium was measured in a patient group consisting of 28 Malian women presenting peripartum heart failure and in a control group of 28 healthy breast-feeding Nigerien women of comparable age. The criteria for matching the two groups was parity (similar number of deliveries) since multiparity is a risk factor for peripartum cardiomyopathy. The Wilcoxon test (nonparametric) was used to compare the 2 groups considering up value0.05 as significant. Plasma selenium was significantly lower in patients from Mali than in controls from Niger (65 +/- 17 ng/ml vs. 78 +/- 17 ng/ml, p = 0.01). The results of this study showing lower plasma selenium in Bamako patients with peripartum cardiomyopathy than in a matching healthy control population confirms the previous data from the Niamey study.

Leaves of plants have the ability to accumulate the long-lived fission product (99)Tc. In the present work, an attempt was made to separate and characterize technetium species formed in maize grown on soil contaminated with Tc(VII)O(4)(-) solution. Data obtained from selective extraction, a Phosphorimager and liquid scintillation were employed.

Cardiac-related death of HIV-positive patients is not rare. The etiology of AIDS-associated dilated cardiomyopathies often remains unknown, even at autopsy. We report an observation associated to a severe deficit in selenium. The patient had been diagnosed as HIV-positive 2 years before. He presented Pneumocystis carinii pneumonia then Cryptococcus meningitis. Two months later he was hospitalized for pancreatitis and cachexia. He presented global heart failure that lead to death. No microorganism was found in myocardium at autopsy but plasma selenium was dramatically decreased (24 micrograms/L). The deficit in selenium has been associated to a dilated cardiomyopathy in non-AIDS patients. HIV-positive patients have an early decrease in plasma selenium, this concentration is dramatically decreased in malnourished patients. Selenium deficit might be the cause of some of the AIDS-related dilated cardiomyopathies and selenium supplementation might be useful in these patients.

In this study, we performed nuclear microprobe analysis on cultured human ovarian cancer cells exposed to pharmacological concentrations of 4′-iodo-4′-deoxydoxorubicin (IDX), an anthracycline anticancer drug. We observed that iodine and iron cellular distributions were strongly correlated, suggesting intracellular iron chelation by the anthracycline. The average cellular iron concentration did not change during drug exposure, but the cellular distribution of iron was modified following the preferential nuclear localization of iodine, as determined by single cell microanalysis. These results are important for understanding the cellular pharmacology of anthracyclines. They suggest that iron cellular delocalization and its subsequent nuclear accumulation may participate to the overall cytotoxicity of IDX, and more generally to anthracycline antitumor activity.

Platinum and trace metal distributions of a human ovarian adenocarcinoma cell line, IGROV1, and a subline resistant to the antitumor agent cisplatin were compared using nuclear microprobe analysis. The cisplatin-resistant cell line IGROV1-DDP exhibited a cytologically heterogeneous cell population. Two subpopulations were distinguished, small mononuclear cells, morphologically similar to the parental cells IGROV1, and enlarged polynuclear cells. Quantitative mapping of platinum and essential trace metal such as manganese, iron, copper and zinc was performed at the cellular level. Elemental maps were obtained with 2 mu m spatial resolution. Platinum appeared uniformly distributed within the cells, in all cell types. The same was true for copper and zinc. In some cases, iron maps showed preferential localization in the perinuclear region, especially in IGROV1-DDP polynuclear cells. Cisplatin resistance was associated with decreased platinum and iron concentrations and increased levels of copper and zinc. Decreased drug accumulation was encountered in both subpopulations of the resistant cell line. In contrast, high inter-individual variation of copper content was noticed in this cell line suggesting that in vitro cisplatin selection of human ovarian adenocarcinoma resistant cells can bring about the emergence of distinct cellular phenotypes.

The effect of the addition of MgCl(2) and of taurine on the concentration and distribution of ions, present in physiological fluid, in epithelial (EL) and compact (CL) layers of the human amniotic membrane has been investigated using the Bordeaux nuclear microprobe. Particle induced X-ray emission and Rutherford backscattering spectrometry techniques had been used to provide quantitative measurements. In physiological medium (Hanks' solution), the monovalent ions (Na+, K+, Cl-) concentrations were identical in both layers. This data indicates that the compact layer acts as a buffer which fix minerals. Mg(2)+, Ca(2)+ and phosphorus levels were higher in EL than in CL. The addition of MgCl(2) in Hanks' solution induced a decrease of the monovalent ions concentration in both layers except Na+ level in EL which remained constant, an increase of the Mg(2)+ level in both layers while the Ca(2)+ and phosphorus remained constant. Addition of taurine in the Hanks' solution implicated several observations: taurine had no effect on the Na+, Mg(2)+, Ca(2)+ and phosphorus levels in EL and CL, but decreased the K+ and Cl- concentrations in both layers. The quantitative results may be related to electrophysiological observations on ionic exchanges through channels and paracellular pathways. The nuclear microanalysis processing may be of great interest to explain pregnancies complicated by poly or oligohydramnios.

The effect of the addition of MgCl2 on the Na+, K+, and Cl- concentration and distribution in epithelial and compact layers of the human amniotic membrane was investigated using the Bordeaux nuclear microprobe. Particle-induced X-ray emission and Rutherford backscattering spectrometry techniques were used to provide quantitative measurements. In physiological medium (Hanks' solution), the monovalent ion concentrations were identical in both layers. The addition of Mg2+ ions in Hanks' solution induced a decrease of, K+, and Cl- concentration in both layers and, Na+ concentration in the compact layer. The results obtained from nuclear microanalysis might be explained from electrophysiological data which indicate that the addition of Mg2+ ions results in an increase in the cellular, paracellular and exchanger ion pathways.

Objective: To investigate red blood cell (RBC) and plasma fatty acids (FA) in HIV-positive patients in relation to oxidative stress and nutritional or immunologiical status. Design and Methods: FA, plasma selenium, vitamins A and E were measured in 95 patients divided into four groups according to CD4 cells. Results: Poly- and di-unsaturated FA (PUFA, DUFA) decreased and saturated FA (SFA) increased in RBC in the patients below 400/mm3 and in plasma in the patients below 50/mm3 RBC SFA correlated to CD4 cells, PUFA to MDA. Unlike vitamin E, plasma vitamin A and selenium decreased in most groups. Plasma SFA and MUFA correlated negatively to selenium and PUFA and DUFA to vitamin E. No correlation was found between PUFA and nutritional markers. Conclusion: FA seem to be modified during HIV infection by oxidative stress and disease evolution, but not by denutrition.

Plasma antioxidant status can be evaluated by selenium, retinol and a-tocopherol. The present study concerns 89 HIV-1 positive patients. The plasma level of selenium was determined by PIXE (proton-induced X-ray emission analysis) and by measurement of levels of vitamins A and E by HPLC. The data were compared to controls; among the HIV-1 patients, significant differences were found for plasma selenium between groups selected on the basis of the CD4 lymphocyte count. Differences were also observed for plasma retinol between the HIV-1 patients and the control subjects. Correlations with other nutritional and immunological parameters were shown.

The effect of magnesium and taurine on the permeability of cell membranes to monovalent cations has been investigated using the Bordeaux nuclear microprobe. PIXE and RBS techniques have been used to provide quantitative measurements and ion distributions in the isolated amniotic membrane. This physiological model for cellular exchanges allowed us to reveal the distribution of most elements involved in cellular pathways and the modifications under different experimental conditions of incubation in physiological fluids. The PIXE microanalysis provided an original viewpoint on these mechanisms. Following this first study, the amnion compact lamina was found to play a role which was not, up to now, taken into account in the interpretation of electrophysiological experimentations. The release of some ionic species, such as K + , from the epithelial cells, during immersion in isotonic fluids, could have been hitherto underestimated.

We have measured the fatty acid (FA) composition of erythrocyte membranes and plasma anti-oxidants in HIV+ patients. Saturated FA are higher and poly-unsaturated FA lower than in controls (P = 0.02). Selenium (Se) is lower in patients less than 400 CD4 cells/mm3 (P = 0.002). Vitamin A is lower in the HIV+ regardless of the CD4 cell count. Se and vitamin A are correlated to nutritional markers (body mass index and albumin).

We have measured TNF-alpha and interferon alpha in 95 HIV positive patients and 20 healthy subjects. TNF-alpha was higher in the HIV+ patients (P = 0.0001) and was correlated to the CD4 cell count (P = 0.02) and cholesterol (negatively) (P = 0.04). Interferon-alpha was correlated to the wasting syndrome (P = 0.002), hypertriglyceridemia (P = 0.004) and haematocrit (P = 0.04).

A specific selenium deficiency is a risk factor for Keshan disease, an endemic cardiomyopathy observed in China. In a Sahelian area of Niger, plasma selenium concentration was measured by neutronic activation and particle induced X-ray emission in 35 black African women with peripartum cardiomyopathy and 36 breast-feeding women without cardiac failure as controls. The plasma selenium concentration in patients was lower (48 +/- 25 ng/ml, mean +/- standard deviation) than in controls (77 +/- 16 ng/ml) (P less than 0.0001). Moreover, 40% (14/35) patients with peripartum cardiomyopathy had very low plasma selenium concentrations, below 45 ng/ml, versus none in controls. A low plasma selenium concentration is a risk factor for the Sahelian peripartum cardiomyopathy.

Antioxidant status can be evaluated by blood selenium, vitamins A and E. The level of selenium was determined in whole blood, erythrocytes and plasma of 170 French people (70-95 years old) healthy and with intercurrent illness, by using PIXE (proton-induced X-ray emission analysis). These results are discussed with other values from the literature. Plasma levels of vitamins A and E have been measured by HPLC. All data were compared with those obtained for younger subjects. Healthy elderly people residing in a geriatric home received selenium supplements during 1 month. The influence of this supplementation brought to light a deficiency for this trace element. The correlation of aging and nutritional requirements with immune function, heart and cancer death rate is presented and discussed.