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PubMed2005

The legacy of monazite processing in Brazil.

The exploitation of natural resources containing naturally occurring radionuclides may lead to enhanced levels of radioactive isotope and enhanced potential for exposure to naturally occurring radionuclides in products, by-products, residues or wastes. Such resources include, for instance, monazite, the processing of which, in Brazil, generated a great amount of radioactive residues, being stored in buried concrete tanks, in temporary storage buildings and in sealed trenches. In addition, during the 1980s there were no radiological protection rules concerning the storage and transportation of these kinds of residues. Mineral radioactive residues were used as landfills and the residues of chemical processes contaminated floors and buildings. The decommissioning process and cleaning of old plants have generated tons of wastes that has been added to previously produced wastes. This paper reports and discusses the cycle of monazite in Brazil and its consequences in terms of site remediation and amount of wastes and residues generated and stored.

Brazil↗
PubMed1980

[Lymphoedema of the upper limb following surgery or radiotherapy. Investigation by indirect radioactive lymphography (author's transl)].

Indirect radioactive isotope lymphography using intravenous 99 m Tc-labelled colloidal antimony sulfide was performed on 76 patients with lymphoedema of the upper limb consecutive to surgery or radiotherapy. The time required to reach 50% of maximum radioactivity was taken as index of the lymphatic flow rate, and the patients were divided into 3 groups depending upon the index (< 20 min; 20-60 min; > 60 min). It appears that in huge lymphoedemas the lymphatic flow rate index may remain subnormal, owing to associated veno-occlusive oedema. This non-invasive method provides data on the site and, frequently, on the nature and importance of lymph blockade. It might also help to predict the efficacy of a new drug currently under study.

Arm↗
PubMed1989

Metabolism of collagen in bone of adjuvant induced arthritic rat.

The metabolism of collagen was examined in bones of rats rendered adjuvant arthritis and matched controls using radioactive isotopic tracer techniques. The rate of the synthesis was studied after the incorporation of tritiated labeled proline into the total bone collagen and determining the content of total hydroxyproline and estimating the specific and total activities of radioactive labeled hydroxyproline. The rate of the catabolism was examined by measuring the activities of various collagen degrading proteolytic enzymes in the bone extract and by estimating the total content of hydroxyproline excreted in the urine. The degradation of collagen was also followed by measuring the specific and total radioactivities of (3H)-hydroxyproline in the urine. When (3H)-proline was injected into the adjuvant arthritic rat, the specific and total radioactivities of (3H)-hydroxyproline in bone collagen were reduced significantly in diseased bone. The activities of various enzymes involved in the catabolism of collagen and other extracellular matrix components were appreciably elevated (about 2-3 fold) in the bone extract of arthritic rat. Similarly, the specific and total activities of (3H)-hydroxyproline in urine samples were also greatly increased in arthritic rats. In addition, the decreased content of hydroxyproline in total bone collagen was accompanied by the increased excretion of urinary hydroxyproline in adjuvant arthritic rats. The results clearly suggest that the arthritic disease induces the qualitative and quantitative changes in bone composition and causes the alteration in the metabolism of collagen in diseased tissue. These observations could therefore, explain in part, the altered response of connective tissue of bone to inflammation and arthritis.

Acetylglucosaminidase↗
PubMed2000

Elemental and radioactive analysis of commercially available seaweed.

Edible seaweed products have been used in many countries, specifically Japan, as a food item. Recently these products have become popular in the food industry because of a number of interesting medicinal properties that have been associated with certain edible marine algae. Very little control exists over the composition of these products, which could be contaminated with a number of agents including heavy metals and certain radioactive isotopes. Fifteen seaweed samples (six local samples from the coast of British Columbia, seven from Japan, one from Norway and one undisclosed) were obtained. All samples were analyzed for multiple elements, using ICP mass spectrometry and for radioactive constituents. It was found that six of eight imported seaweed products had concentrations of mercury orders of magnitude higher than the local products. Lead was found at somewhat higher concentrations in only one local product. Laminaria japonica had the highest level of iodine content followed by Laminaria setchellii from local sources. Only traces of cesium-137 were found in a product from Norway and radium-226 was found in a product from Japan. Arsenic levels were found to be elevated. In order to estimate the effect of these levels on health, one needs to address the bioavailability and the speciation of arsenic in these samples.

British Columbia↗
PubMed1976

The hybrid resolution approach to automated autoradiographic analysis.

The use of radioactive isotopes in the investigation of cells and their relations to an organism as a physiologic unit is an important area of research to the biologist. The manual analysis of the autoradiographs which result from the use of radioactive tracers is, however, very time consuming and prone to error. This paper describes the utilization of hybrid resolution image processing techniques for the rapid and automatic analysis of tissue region autoradiographs. Nine regional features can be extracted and six properties characterized using the present system implementation. Priliminary measurements on two tissue types show good agreement between manual and automated readings.

Autoanalysis↗
PubMed1991

Connective tissue metabolism in bone and cartilage of adjuvant arthritic rat.

The metabolism of connective tissue matrix components such as glycosaminoglycans and glycoproteins was investigated in normal as well as pathological tissues of bone and cartilage associated with adjuvant arthritis using rat as animal model of the disease. The inflammatory process of adjuvant arthritis was induced in rats with the inoculation of Freund's adjuvant containing heat killed Mycobacterium tuberculosis suspended in paraffin oil. The changes in the metabolism of matrix components in bone and cartilage were examined using radioactive isotopic labeling measurements during the acute as well as chronic phases of arthritic disease. The glycosaminoglycans were fractionated into sulfated and non-sulfated glycosaminoglycans by chemical and enzymic modifications. The biosynthesis of sulfated glycosaminoglycans was evaluated using radioactive labeled (35S)-sulfate. Alterations were demonstrated in the metabolism of connective tissue in the bone and cartilage tissues of arthritic rat. The results obtained showed an increased incorporation of radioactive sulfate in specimens of bone and cartilage during the process of adjuvant arthritis. The contents of sulfated as well as non-sulfated glycosaminoglycans were found to be increased in both the tissues of arthritic rat. Similarly, the amount of total glycosaminoglycans was also found to be increased significantly in the diseased tissues. In addition, various components of tissue glycoproteins such as fucose, sialic acid and total hexose were found to be elevated in insoluble fractions of bone and cartilage during the diseased state. The effects of experimentally induced adjuvant arthritis on the connective tissue were discussed in the light of changes taking place in the metabolism of glycosaminoglycans and glycoproteins in bone and cartilage of arthritic rat.

Animals↗
PubMed1986

Distribution of intrapleural and intravenous Corynebacterium parvum in humans; 99mTc-, and 131I-labeled bacteria.

The distribution of Corynebacterium parvum labeled with 131iodine or 99mtechnetium was studied in 17 patients with bronchogenic carcinoma. The labeled bacteria were given intravenously or intrapleurally and monitored by whole-body gamma tracking and samples of blood and urine. Even though the rate of physical decay is quite different for 131iodine and 99mtechnetium, the tracking time of labeled bacteria was limited to 24 h after injection for both radioactive isotopes. Technetium labeling was preferred because of greater imaging resolution and less radiation dose to the patient. Following intravenous administration, labeled C. parvum was found predominantly in the liver and spleen, and in a lesser amount in the lung. Radioactivity was confined to the pleural cavity after intrapleural injection. These results suggest the combined intravenous and intrapleural route of adjuvant immunosupportive agents such as C. parvum for operable lung cancer patients.

Adjuvants, Immunologic↗
PubMed2002

Stable isotope labeling by amino acids in cell culture, SILAC, as a simple and accurate approach to expression proteomics.

Quantitative proteomics has traditionally been performed by two-dimensional gel electrophoresis, but recently, mass spectrometric methods based on stable isotope quantitation have shown great promise for the simultaneous and automated identification and quantitation of complex protein mixtures. Here we describe a method, termed SILAC, for stable isotope labeling by amino acids in cell culture, for the in vivo incorporation of specific amino acids into all mammalian proteins. Mammalian cell lines are grown in media lacking a standard essential amino acid but supplemented with a non-radioactive, isotopically labeled form of that amino acid, in this case deuterated leucine (Leu-d3). We find that growth of cells maintained in these media is no different from growth in normal media as evidenced by cell morphology, doubling time, and ability to differentiate. Complete incorporation of Leu-d3 occurred after five doublings in the cell lines and proteins studied. Protein populations from experimental and control samples are mixed directly after harvesting, and mass spectrometric identification is straightforward as every leucine-containing peptide incorporates either all normal leucine or all Leu-d3. We have applied this technique to the relative quantitation of changes in protein expression during the process of muscle cell differentiation. Proteins that were found to be up-regulated during this process include glyceraldehyde-3-phosphate dehydrogenase, fibronectin, and pyruvate kinase M2. SILAC is a simple, inexpensive, and accurate procedure that can be used as a quantitative proteomic approach in any cell culture system.

3T3 Cells↗
PubMedDate not supplied

Chernobyl three years later: radiobiologic evaluation of a radioactive contamination.

On April 26, 1986, after partial fusion and confining loss by explosion of a nuclear reactor, 5 x 10(7) Ci of radionuclides escaped from Chernobyl. Three years later, maps show contamination by radioactive isotopes (formed during that period) of 21,000 km2 of Soviet soil, mainly in Byelorussia and part of the Ukraine. Decontamination measures have not been effective to date and 135,000 persons are being followed medically, taking into account the radioactive doses they received. An initial excess of morbidity from solid tumors has been noted much sooner than in the case of Hiroshima and Nagasaki, but its significance is in dispute. Three years later, only the extent of the ecologic disaster caused by the radioactive contamination can be confirmed. It is too early to draw conclusions about radiation-induced carcinogenesis for the contaminated population.

Accidents↗
PubMed1972

Technique for measuring 14 CO 2 uptake by soil microorganisms in situ.

Uptake of (14)CO(2) in soils due to algae or sulfur-oxidizing bacteria was examined by incubation of soil samples with gaseous (14)CO(2) and subsequent chemical oxidation of biologically fixed radioactive isotope to (14)CO(2) for detection with a liquid scintillation counting system. The (14)CO(2) was added to the soil in the gas phase so that no alteration of the moisture or ionic strength of the soil occurred. Wet oxidation of radioactive organic matter was carried out in sealed ampoules, and the (14)CO(2) produced was transferred to a phenethylamine-liquid scintillation counting system with a simply constructed apparatus. The technique is inexpensive and efficient and does not require elaborate traps since several possible interfering factors were found to have no harmful effects. Experiments in coal mine regions and in geothermal habitats have demonstrated the ecological applicability of this technique for measurement of CO(2) fixation by sulfur-oxidizing bacteria and soil algae.

Bacteria↗
PubMed2000

Determination of stable isotopic enrichment and concentration of glycerol in plasma via gas chromatography-mass spectrometry for the estimation of lipolysis in vivo.

Measuring glycerol's rate of appearance into the plasma compartment provides an excellent estimation of whole-body lipolysis. The glycerol rate of appearance can be calculated by estimating the plasma dilution of continuously infused stable or radioactive isotopes of glycerol. Previously, determination of glycerol stable isotopic enrichment has required either chemical ionization gas chromatography-mass spectrometry (GC-MS) or electron impact ionization GC-MS in which a fragment containing only a portion of the glycerol molecule was measured. The present method uses tert.-butyldimethylsilyl (tBDMS) derivatization and electron impact ionization to measure a fragment including the entire glycerol molecule. The method determines concentration and enrichment of plasma glycerol in a simple, precise, and cost-efficient manner, providing a basis from which lipid homeostasis can be assessed.

Animals↗
PubMed1997

Pretargeting strategies for radio-immunoguided tumour localisation and therapy.

The selective recognition of tumour cells by monoclonal antibodies, labelled with radioactive isotopes, for use in diagnosis and treatment, forms the basis of immunoscintigraphy, radio-immunoguided surgery and radio-immunotherapy. Research into the application of these systems has encountered multiple difficulties, most notably a low tumour to non-tumour ratio of radioactivity. The development of pretargeting systems, separating the individual steps of tumour cell targeting and the introduction of the radioactive label, have led to significant increments in tumour to non-tumour ratios and an improvement in diagnostic accuracy. Before pretargeting strategies are applied clinically, a thorough understanding of these systems is required and forms the backbone of this report. Clinical examples of early trials have already confirmed many of the theoretical advantages of pretargeting systems and new protocols are already being investigated.

Antibodies, Monoclonal↗
PubMed2006

High-resolution quantitative imaging of mammalian and bacterial cells using stable isotope mass spectrometry.

BACKGROUND: Secondary-ion mass spectrometry (SIMS) is an important tool for investigating isotopic composition in the chemical and materials sciences, but its use in biology has been limited by technical considerations. Multi-isotope imaging mass spectrometry (MIMS), which combines a new generation of SIMS instrument with sophisticated ion optics, labeling with stable isotopes, and quantitative image-analysis software, was developed to study biological materials. RESULTS: The new instrument allows the production of mass images of high lateral resolution (down to 33 nm), as well as the counting or imaging of several isotopes simultaneously. As MIMS can distinguish between ions of very similar mass, such as 12C15N- and 13C14N-, it enables the precise and reproducible measurement of isotope ratios, and thus of the levels of enrichment in specific isotopic labels, within volumes of less than a cubic micrometer. The sensitivity of MIMS is at least 1,000 times that of 14C autoradiography. The depth resolution can be smaller than 1 nm because only a few atomic layers are needed to create an atomic mass image. We illustrate the use of MIMS to image unlabeled mammalian cultured cells and tissue sections; to analyze fatty-acid transport in adipocyte lipid droplets using 13C-oleic acid; to examine nitrogen fixation in bacteria using 15N gaseous nitrogen; to measure levels of protein renewal in the cochlea and in post-ischemic kidney cells using 15N-leucine; to study DNA and RNA co-distribution and uridine incorporation in the nucleolus using 15N-uridine and 81Br of bromodeoxyuridine or 14C-thymidine; to reveal domains in cultured endothelial cells using the native isotopes 12C, 16O, 14N and 31P; and to track a few 15N-labeled donor spleen cells in the lymph nodes of the host mouse. CONCLUSION: MIMS makes it possible for the first time to both image and quantify molecules labeled with stable or radioactive isotopes within subcellular compartments.

Adipocytes↗
PubMed1977

Optic disc edema in raised intracranial pressure. IV. Axoplasmic transport in experimental papilledema.

Tritiated leucine was injected intravitreously into the eyes of rhesus monkeys that had developed papilledema secondary to implantation of intracranial balloons. Autoradiographic studies of the optic nerve head showed that six hours after intravitreous injection of the isotope the fast component of axoplasmic transport accumulated in the regions of the lamina choroidalis and lamina scleralis. The slow component arrived at the optic nerve head two to four days after injection, and the swollen axons of the entire optic nerve head were filled with radioactive isotopes. Twelve days after injection of isotope, the axons in the optic nerve head were still diffusely labeled. Disturbance of axoplasmic transport was one of the primary events resulting in swelling of axons in papilledema. The pattern of axoplasmic disturbances in papilledema secondary to raised intracranial pressure was similar to that observed in papilledema secondary to ocular hypotony or increased intraocular pressure. Ocular hypotony, raised intracranial pressure, and increased intraocular pressure appear to share a final common pathway. All these conditions apparently converge into this final common pathway of disturbance of axoplasmic transport to give rise to papilledema.

Animals↗
PubMed1997

Effect of freeze-drying or gamma-irradiation on remodeling of tendon allograft in a rat model.

Freezing or freeze-drying and gamma-irradiation are techniques currently used for processing tendon allografts. However, it is still unknown how these processing methods affect graft remodeling. In this study, we used a rat patellar tendon transplantation model to investigate the effect of various processing methods on remodeling by quantifying loss of collagen labeled with a radioactive isotope. The grafts were divided into the following four groups according to the processing method: fresh-frozen, freeze-dried, fresh-frozen and gamma-irradiated, or freeze-dried and gamma-irradiated. The percentage of donor collagen, calculated from hydroxyproline content and radioactivity level, was used as an indicator of graft remodeling. At 2 weeks, the level of donor collagen in the fresh-frozen group was 62%; in the freeze-dried group, 59%; in the fresh-frozen and irradiated group, 57%; and in the freeze-dried and irradiated group, 44%. At 4 weeks, the percentage of donor collagen remaining in grafts decreased to 38% in the fresh-frozen group, 19% in the freeze-dried group, 27% in the fresh-frozen and irradiated group, and 12% in the freeze-dried and irradiated group. Finally, at 12 weeks, the levels were 19% in the fresh-frozen group, 20% in the freeze-dried group, 15% in the fresh-frozen and irradiated group, and 6% in the freeze-dried and irradiated group. The percentages of donor collagen in the freeze-dried and the fresh-frozen and irradiated groups were significantly lower than that in the fresh-frozen group at 4 weeks. The values for the freeze-dried and irradiated group were significantly lower than those for the fresh-frozen and irradiated group at 4 and 12 weeks. These data suggest that freeze-drying, freeze-drying followed by gamma-irradiation, and fresh-freezing followed by gamma-irradiation temporarily accelerate graft remodeling.

Animals↗
PubMed2002

Direct detection of isotopically labeled metabolites bound to a protein microarray using a charge-coupled device.

A charge-coupled device (CCD) was used to quantitatively detect isotope-labeled ligands bound to a protein microarray. Protein microarrays with protein dots, 10-50 microm in diameter, were fabricated on an aluminized Mylar film using an electrospray deposition technique. Proteins in dots were immobilized by cross-linking in glutaraldehyde vapor. After contact with solutions of isotope-labeled metabolites, the protein microarrays were washed, dried and placed face down onto the surface of a standard B/W video CCD chip with the protective window removed. We show here that such a simple inexpensive CCD detector can be used to quantify distribution of 14C and other radioactive isotopes on microarrays.

Automation↗
PubMed2000

Mobilisation of cadmium by meso- and racemic-2,3-dimercaptosuccinic acid (DMSA) in rats.

A higher efficiency of cadmium binding with racemic than with meso-2,3-dimercaptosuccinic acid (rac-DMSA; meso-DMSA) was found in an in vitro speciation model by Fang et al. (1996). This finding has not yet been tested in vivo. This paper presents results on mobilisation of cadmium by meso- and rac-DMSA in rats. Cadmium chloride was administered as the radioactive isotope 109Cd intraperitoneally to all animals. One group was an untreated control and two groups were treated with meso- and rac-DMSA, respectively. Treatment with chelators was applied twice, immediately after 109Cd and 24 hr afterwards intraperitoneally at the dose of 1 mmol/kg, each. Six days later radioactivity was measured in the liver and kidneys. Whole-body counting was carried out on days 1, 2, 3 and 6 of the experiment. At the end of the experiment, both treatments caused a decrease in 109Cd whole-body retention with rac-DMSA being more efficient (decrease from 83% in control to 74% and 64% in groups treated with meso- and rac-DMSA, respectively). The same reduction of 109Cd was obtained by both chelators in the liver (from 57% to about 47%). In the kidney only rac-DMSA produced significant reduction of 109Cd (from 5.3% to 3.5%). In conclusion, these results show modest reduction of cadmium in the body by two isoforms of DMSA with rac-DMSA being slightly more efficient than meso-DMSA.

Analysis of Variance↗
PubMed2001

The (13)C-urea breath test for non-invasive diagnosis of Helicobacter pylori infection: which procedure and which measuring equipment?

1) The (13)C-urea breath test is one of the most important non-invasive methods for detecting Helicobacter pylori infection in both pre- and post-treatment phases. 2) In order to render the test less expensive and more rapid, a series of modifications have recently been proposed concerning the dose of (13)C-urea and its formulation, as well as the type of measuring equipment used for detecting (13)CO(2) in breath samples. 3) The use of small doses (40--50 mg) of isotope in gelatin capsules or mixed with citric acid in rapid-releasing tablets seems to be promising as it shortens sampling time to 10--20 min. 4) Infrared spectroscopy and laser-assisted ratio analysis equipment are two new valid and less expensive alternatives to conventional isotope mass spectrometry for (13)C analysis in breath. The (13)C-urea breath test is one of the most accurate non-invasive tests for diagnosing Helicobacter pylori infection. This method has become increasingly popular in the last decade since it employs an innocuous, non-radioactive isotope that can be safely used in both children and adults. The test has been recently simplified by reducing the dose of (13)C-urea used, by adopting shorter sampling times and by using new and cheaper measuring methods for (13)C analysis in the breath samples. These include nondispersive isotope-selective infrared spectroscopy (NDIRS) and laser-assisted ratio analysis (LARA), which greatly differ from each other in their technical characteristics and cost. Both NDIRS and LARA are valid alternatives to conventional isotope ratio mass spectrometry (IRMS), although LARA appears to be more suitable for large laboratories or gastroenterological centres, which need to process many breath samples per day, whereas NDIRS seems to be more suitable for small laboratories or doctors' offices.

Breath Tests↗