[en] Analytical ion microscopy has been applied to the study of distribution of stable and radioactive iodine in the thyroid gland. Analytical images, each of them representing the distribution of one isotope of iodine, can easily be obtained in a few seconds from an Epon section with a resolution of 0.5 micron. In thyroids of normal rats, intrafollicular and intracytoplasmic stable 127I can be clearly distinguished. After thyreostimulin injection, a rapid and important redistribution of 127I is observed which reflects an intense cytoplasmic reabsorption of intrafollicular iodine. After injection of a long-lived isotope of iodine, 129I, the progressive incorporation of this isotope has been observed and the images of the natural iodine 129I have been compared to the images of 127I. An unusual iodine distribution has been observed in proliferating cells of an autonomous nodule. The very high sensitivity of this method makes possible the study of intracellular and extracellular stable iodine in the thyroid gland in a number of physiological and pathological conditions; its ability for isotopic analysis in microscopic volumes offers new possibilities for kinetic studies of iodine metabolism. However, in the present state of the art the specimen cannot be studied at the ultrastructural level as it is with other methods, and some difficulties remain in qualitative analysis such as the contamination of spectra with organic mass fragments which makes difficult the study of some elements such as sulfur. In addition, the matrix effect on ionization efficiency or on sputtering rate makes quantitative analysis difficult. In the future, image processing systems will be needed for a better quantitative interpretation

[en] The cathodoluminescence (CL) emission of fluorescent species submitted to electron beam irradiation in a scanning electron microscope may be used to reveal the localisation of the emitter at microscopic level. This technique has been applied to the study of human renal biopsies with membraneous glomerulonephritis. Cryosections of biopsies were stained with specific antibody, labelled either by fluorescein or by rhodamine. Rhodamine exhibited a stronger luminescence and a greater resistance to the 'beam effect' than fluorescein. The authors obtained CL panchromatic pictures of sections labelled with rhodamine at enlargements up to x15000, without noticeable quenching of emission. (author)

[en] This paper discusses analytical ion microscopy (AIM) as a tool developed for the chemical analysis of microscopic or submicroscopic volumes in a solid sample which may be applied to the study of biological tissues. The main advantage of this method is its very high sensitivity which makes possible for the first time analysis of elements at a trace concentration (0.1 ppm or less) in a microvolume. Isotopic analysis is also possible and images of distribution of most stable or radioactive nuclides are easily obtained in a tissue section with a resolution of 0.5 um. This paper presents the potentiality of AIM in cell biology and cell pathology

[en] Some nickel compounds (Ni₃S₂,Ni) induce tumours in muscle, while others have no effect (NiO). It has been suggested that the carcinogenicity of nickel is related to its penetrating power (phagocytosis) in transformed cells. The penetration of various nickel salts into cultured rhabdomyosarcoma cells (RhC) was studied. Electron microscopy and microanalysis were used to study the ultrastructure and intracellular localization of nickel in ultra-thin sections. Nickel subsulfide (Ni₃S₂) and nickel oxide (NiO) penetrated into cells and were concentrated in vacuoles, exhibiting a particular affinity for membrane structure. They subsequently appeared to be eliminated in the extracellular medium. Colloidal nickel and iron carbonyl, on the other hand, did not penetrate these cells. Various tumoral and normal cells were compared for their ability to phagocytose Ni₃S₂; it was found that these compounds penetrated only RhC and macrophages. In vivo studies have demonstrated the various carcinogenic properties of nickel and two of its salts. Comparison with in vitro results suggests that the phagocytosis of nickel compounds is not directly related to eventual induction of a tumour. No nuclear localization could be detected, but a mechanism for concentration and elimination of these compounds, and especially for rhabdomyosarcoma tumour cells, was suggested

No abstract available

[en] The anti-viral drug HPA-23 (ammonium 21-tungsto-9-antimonate) has been proposed for use in the combat against AIDS. The two elements tungsten (W) and antimony (Sb) in the molecule enable the intracellular localization and possible breakdown of the product to be studied using electron probe microanalysis methods. Such studies have been carried out after intravenous injection of different doses of HPA-23 in the rat followed by removal of the liver, kidney, thymus, spleen, bone marrow, and lung. HPA-23 was concentrated in the lysosomes and localized in the macrophages of different tissues (thymus, spleen, and bone marrow). The W/Sb ratio was identical in these macrophages. This localization is perhaps relevant to the mechanism of action of HPA-23

[en] Chronic intratacheal administration of ²³⁷Np to rats was performed during 6 weeks. The total dose administered was 45.8 kBq. Two methods, electron microscopy and electron probe X-ray microanalysis, were used to determined the intracellular sites of localization of ²³⁷Np. Clusters of dense granules were observed in nuclei of pneumocytes and proximal tubular cells of the kidneys. These clusters have been shown to contain neptunium associated with phosphorus, sulfur and calcium. Alternations of nuclei and ultrastructural cytoplasmic lesions were observed. The absorbed doses in lungs and kidneys were very low. These results suggest that the chemical toxicity of ²³⁷Np is more important than its radiological toxicity. 30 refs., 2 figs

[en] In order to study the relationship between amiodarone-induced hepatic phospholipidosis and liver disease, liver biopsies obtained from 13 patients treated with amiodarone for 4 months to 15 years were investigated by light and electron microscopy. Light microscopy showed pseudoalcoholic liver lesions that were probably related to amiodarone in four cases, various alterations (i.e. cirrhosis, three cases; steatosis and fibrosis, two cases; chronic venous congestion, one case; acute hepatitis, one case) that could be explained by another cause than amiodarone in seven cases and normal liver in two cases. In all cases, electron microscopy showed intralysosomal myelin figures suggestive of phospholipidosis. These myelin figures were associated with intralysosomal electron-dense deposits. In the four cases in which analysis by electron microprobe was performed, it demonstrated large amounts of iodine in the electron-dense deposit-containing lysosomes, indicating the accumulation of amiodarone. These results show that hepatic phospholipidosis is constantly observed in amiodarone-treated patients, whether or not pseudoalcoholic liver lesions are present. This phospholipidosis, which could be only a morphological marker of intrahepatic accumulation of the drug, should not therefore be considered grounds for attributing liver disease to the drug

[en] Three groups of adult female mice (S.w.), were exposed whole-body irradiation of 137-Cesium gamma rays at 2, 4, and 6 Gy/mn). For all groups, samples were taken at 2, 6, and 24 hours after irradiation and immediately fixed in a 1.4 % solution of glutaraldehyde containing 0.1 M sodium cacodylate buffer. Specimens were post-fixed in 1 % osmium tetroxide in the same buffer, then dehydrated in ethanol and 1, 2-epoxy-propane, impregnated in a mixture of propylene oxide and epon before being embedded in pure epon and polymerized at 60 deg C during 24 hours. Using a diamond knife and an ultra-microtome, ultrathin sections of approximately 50 nm thick were cut and deposited on copper grids. The sections were stained with uranyl acetate and lead citrate and studied with the electron microscopy (Philips 300). Early ultrastructural lesions were characterized by condensation of chromatin, convolution and fragmentation of nuclei. Clarification of cytoplasm and mitochondrial alterations were observed in a number of thymocytes depending on the radiation dose although the ultrastructure of the other ones remains normal. These lesions increased according to the length of the post-irradiation period. Clarifications of the cytoplasm with important mitochondrial lesions, as well as modifications of the cytoplasmic membrane were observed 24 hours after irradiation at 2 Gy and a number of polymorphonuclear cells and macrophages were observed in the thymus. Most often a single macrophage contains several apoptotic thymocytes, up to eight. The same alterations were observed in the other irradiated groups, but the extent of damage was much more important. In an other experimentation at 6 Gy the earliest ultrastructural lesions of apoptosis have been observed 15 minutes after the irradiation. (authors)

[en] After intravenous administration of (5 x 2.3 kBq and 5 x 9.25 kBq) plutonium citrate in adult male Sprague Dawley rats, their kidneys are withdrawn and prepared for observation under a transmission electron microscope. Seven days after the first injections, deep cellular alterations are observed in the proximal convoluted tubules. These alterations are mainly mitochondrial. The affected mitochondria are of swollen aspect and have their cristae partially or completely destroyed. Nevertheless within the same tubule we observe non altered cells directly in contact with deeply altered cells. In all the cases the lysosomes of the altered cells appear to be perfectly normal. The cell nuclei are mostly unaltered but a few cases of nuclear fragmentation exist. We also notice some architectural modifications in the brush border and in the betacytomembranes of the proximal convoluted tubule. Equally important mitochondrial alterations are also noticed in the different varieties of glomerular cells. We observe no other glomerular alterations. The major subcellular alterations in the proximal convoluted tubules and in the different varieties of glomerular cells deeply contrast with the distal convoluted tubules which are found to be totally unaltered. These mitochondrial alterations may be due to the α particle disintegration of plutonium which may either directly react with the mitochondria or, through the products of radiolysis of water react with the mitochondria respiration process. However the direct chemo-toxicity of plutonium cannot be neglected. (Authors). 21 refs., 1 fig