[en] The quality control in the environment analysis must be exhaustive in order to assure the measurements of atmospheric contamination. The quality control must be used at the laboratories, the certifications, data treatment, feasibility etc

[en] Synthesis of pyruvaldehyde-bis-(N⁴-methylthiosemicarbazide) (PTSM), used for medical investigation and diagnosis, has been carried out in our Radiopharmaceutical Division in C.A.E. (Ezeiza Atomic Center). PTSM has been obtained introducing modifications to a previous synthesis published by H.G. Petering. (M.P. 236-238 degrees C). TLC, HPLC and IR spectrum controls have been performed. Cu-64 can be obtained by the Cu-63(n,α) and Zn-64(n,p) reactions. This last reaction has been chosen for the production in the RA-3 reactor since it leads to Cu-64 of high specific activity. Two different assays have been performed to obtain the chelate PTSM-Cu-64. The first one has been obtained by buffering the Cu-64 to pH 3-4; adding the PTSM solution to ethanol. The second assay has been carried out by buffering the Cu-64 solution with sodium acetate 3M and adding 100 μl of PTSM solution. Biodistribution studies have been carried out on NIH and rats showing a brain uptake of 4%, 30 minutes after injection. Thus, PTSM-Cu-64 proves a good brain diagnosis agent. (author). 1 ref

[en] Chinese Hamster chromosomes R-banded in vitro were gamma-irradiated and chromatid breaks and rearrangements examined by electron microscopy employing whole-mounting technique. Breaks were preferentially located at the point of transition between G- and R-bands where the chromosome showed an average diameter 71.65 % of the wide condensed R-bands. This result was similar to the average diameter of narrow G-bands. Three chromosomes which were thin sectioned presented their broken terminal end organized as a coil constituted by two 23 nm wide chromatin fibers coiling together. Coils diameter was 43.70 % of the mean chromatid diameter. The border of damage-breakage was analyzed in whole-mounted chromosomes where breaks were photoinduced in BrdU-substituted DNA. Measurements of the angle of the sharp border of damage with respect to the chromatid axis showed a tendency to be more perpendicular as condensation progressed. These results clearly correlate with the several levels of chromatin fiber organization of the metaphase chromosome. (author)

[en] The automatic detection and measurement of defects in heat exchanger tubes is commonly being carried out by industrial inspection systems based on eddy currents techniques. These methods allow the inspection of tubing for defects any type (holes, pits, inclusions, cracks) in any orientation (axial, transverse, or in between) with a relatively low resolution even employing eddy currents probes with optimized configurations and coil orientations. Moreover, in the case of heat exchangers and steam generators with supporting plates, eddy currents techniques present strong limitations for inspecting the areas of the tubes at the neighbourhood of the plates. To overcome these limitations we have developed an automatic industrial inspection system that provides an image of the inner surface of the tubes. The system acquire the image by means of a fibre optic probe of new conception based on a reflectometer principle. The surface of a tube is fully inspected by only one pass of the probe along it. In this work, the configuration and features of the optical probe as well as the whole inspection system are presented. Images of real tubes (with both real and artificial defects for the purpose of calibrations) acquired with a laboratory prototype have been analyzed, demonstrating a precise dimensional characterization of the defects (silhouette, length, width, orientation and position in the tube) with a resolution of about 50 microns, and sensibility of 13 microns. (Author)

[en] Synthesis of Pyruvaldehide-bis-(N⁴-methyl-thio semicarbazone) PTSM used for medical investigation and diagnosis has been carried out in our Radiopharmaceutical Division in Centro Atomico Ezeiza. PTSM has been obtained introducing modifications to a previous synthesis published by H.G. Petering TLC, HPLC and IR, UV spectrum controls have been performed. Cu-64 can be obtained by the Cu-63 (n, γ) and Zn-64 (n,p) reactions. This last reaction has been chosen for the production in the RA-3 reactor since it leads to Cu-64 of high specific activity. Two different assays have been performed to obtain the chelate PTSM-Cu-64. The first one has beer carried out by buffering the Cu-64 solution to pH 3-4; adding the PTSM solution in ethanol. The second assay has been carried out by buffering the Cu-64 solution with sodium acetate 3 M and adding 100 μl of PTSM solution in ethanol. The chelate thus obtained is purified in Sepak C-18. Radiochemical purity has been tested by thin layer chromatography. Biodistribution studies have been carried on NIH mice and Wistar rats showing a brain uptake of 4%, 30 minutes after injection. Thus, FTMS-Cu-64 proves to be a good brain diagnosis agent. (author). 7 refs., 3 figs

[en] The design of an add-on card for PC that enables it to record nuclear pulses provided by two channels is described in this paper. This card carries acts as a pulse discriminator, and according to the software it finds many appliances in radioimmunoassay, nuclear medicine, industry and other fields

[en] The spectrophotometric determination of cerium can be carried out by several methods, which involve either the formation of complexes of cerium(III) and cerium(IV) or the oxidation of suitable reagents by cerium(IV) and further measuring the intensity of the colour of the oxidised matter. The latter methods show a lack of selectivity and low sensitivity owing to the nature of the redox reaction. The methods that involve the formation of complexes have also been shown to have low selectivity and sensitivity. However, the most useful methods are those based on the complexes of cerium(III) with Xylenol Orange and Methylthymol Blue (MTB), but they are affected by many interferences. In this work the reaction of cerium(III) with MTB in the presence of oxalate and cyanide ions was studied at pH 10.2, which improves the sensitivity and the selectivity of the determination of cerium. (author)

[en] Exposure to ionizing radiations is a well-known source of chromosome damage. Here we present a comparison among three different methodologies employed to recognize cytogenetic damage, after an acute exposure of human lymphocytes to 3 Gy of X-rays (100kVp). Scoring of dicentric chromosomes, present in first mitosis ''in vitro'', was the method of preference as dicentrics increased 937.5 times with respect to background. Micronucleus scoring in binucleated-cytokinesis blocked cells showed an increase of 32.5 times, while it was only of 1.46 times when Sister Chromatid Exchanges (SCEs) were analyzed. The estimated probability of an acentric fragment becoming a micronucleus was around 0.25. Intercellular distribution of dicentrics agree with Poisson, while micronucleus were overdispersed. When analyzed at second cycle after damage induction, the dicentrics yield as well as the level of cells with unstable cromosome aberrations, decreased around a half. Finally, SCEs level was similar in cells with or without unstable structural chromosome aberrations. (Author)

[en] A group of 365 patients with pituitary adenoma who underwent postoperatory irradiation were analyzed. Hormone values, both pre and posttreatment, as well as the result of treatment on the symptoms and visual involvement were assessed. Best results were obtained in non-functioning adenomas, with a 100% disease control in the first 3 years, whereas the this percentage was 70% in GH secreting adenomas and 76.9% in prolactinomas. However, after five years, disease control decreases to 85.7% in those with non-secretory adenoma, to 46.7% in patients with GH secreting adenoma and to 30.8% in those presenting prolactinomas. (Author)

[en] The present job describes the technical characteristics and operation of two clinical equipment designed in Cuba, for the determination in vivo of the osseous mineral content in forearm, based on the of gamma absorption technique of a single photon. The development of these equipment and the measurements done with one of them are the first intents carried out in the country to diagnose osseous illnesses by means of this method. (author)