[en] The role of halogen atom as a reaction centre in reactions of organic and inorganic halogen derivatives was considered. It is shown that many of the reactions actually proceed by substitution mechanism in halogen atom rather than in carbon or metal atoms as was assumed earlier. Reasons for increase in reactivity from fluorine- to iodine-derivatives, as well as in the opposite direction, are formulated

[en] Clinical experience with a new tri-iodized contrast medium (Telebrix 300) in cerebral angiography is reported. In one of its forms, Telebrix is available as the pure methylglucamine salt of the newly developed ioxitalaminoacid in 66% aqueous solution, with an iodine content of 300 mg/ml. The results of the use of Telebrix 300 in 302 patients examined with over 600 single vascular visualisations (direct puncture and catheter angiography) are communicated. Unforeseen incidents with permanent neurological disturbances were not observed. Local and general tolerance of Telebrix 300 is excellent, even after large quantities of the contrast medium (up to 300 ml). (orig.)

[en] The contrast production for the chemical elements with the atomic numbers Z=1-83 were determined by computer-tomography. With the formula relation of the Δ-number and the atomic number can one compute the contrast production of any chosen chemical compound. Iodine-free and inorganic iodine-containing contrast media are examined for their contrast production and compared with presently used organic iodine-containing contrast media. The contrast enhancement of organic contrast media in tissue are discussed. (orig.)

[en] Published in summary form only

[en] Radiation dose estimations are usually made with the aid of assessment models in which model parameters such as the transfer factors of radionuclides from one environmental compartment to another are involved. In simple models the parameters are often described as the concentration ratio of a radionuclide between two compartments, when the system is under equilibrium condition. In this paper, the authors introduce the values of the parameters of radioiodine obtained by tracer experiments. Laboratory experiments on the transfer parameters of radionuclides from the atmosphere to rice plant were carried out in the atmosphere-to-crops system (deposition pathway). It is known that the typical chemical species of gaseous iodine in the atmosphere are elemental iodine (I₂) and methyliodide (CH₃I). The deposition characteristics of both chemical species of gaseous iodine to rice grains were obtained. Mass normalized deposition velocity (V_D) and grain number normalized deposition velocity (V_S) of gaseous elemental iodine (I₂) and also methyliodide (CH₃I) on unhulled rice were measured. Both V_D and V_S of methyliodide were about one percent of those of elemental iodine. Distribution pattern of methyliodide between unhulled rice and brown rice was significantly lower than that of elemental one. For wet deposition, we investigated the retention of radioiodines (iodide [I^-] and iodate [IO₃^-] on rice grains and their translocation from the surface of the grains to brown rice. Though the ears were dipped into the solution containing ¹²⁵I^- or ¹²⁵IO₃^- more than 15 min., both iodine species in the solutions were hardly taken up to the rice grains. The transfer rates of iodide and iodate, which are defined as 'the amount of the iodine in brown rice' divided by 'the amount of iodide in unhulled rice' were about 0.015 and 0.04, respectively. The rates were not changed with time after the radioiodine application. (author)

No abstract available

[en] A system was developed which allowed the determination of four different atmospheric iodine species by preparing glass microfibre filters, which were arranged in consecutive order, in a specific way. Particulate iodine was collected by a particle filter, HI and I₂ by a NaOH impregnated filter, HOI was adsorbed on a TBAH impregnated filter and organoiodine was adsorbed on a filter loaded with activated charcoal. These behaviours were checked by extensive model experiments. Two or more filters of the same type were used in series to show the degree of collection of one iodine species. Two European samples, one of continental and one of marine origin, and two Antarctic samples were analysed by this filter system using isotope dilution mass spectrometry (IDMS) for quantification. The distribution pattern for the different iodine species is similar for the two European samples. Organoiodine is found to be the most abundant species whereas in Antarctica the HI/I₂ fraction is up to nearly 50% of the total iodine. The particulate iodine fraction is higher in Europe than in Antarctica, which is due to the low particle concentration in the remote area of Antarctica. The higher HI/I₂ and HOI fractions found at the North Sea compared with the continental sample indicate that the ocean is a primary source of these species. Concentrations in the range of (0.3-3.1) ngI/m³ were analysed for particulate iodine, (0.4-1.3) ng I/m³ for HI/I₂, (0.2-1.8) ng I/m³ for HOI and (0.4-7.6) ng I/m³ for organoiodine. The detection limits varied with the variances of the blank values of the different filters and lay between 0.02 ng I/m³ and 0.24 ng I/m³ using sample volumes of 70 m³ air. (orig.)

[en] A definitive method of isotope dilution mass spectrometry (IDMS) was developed to determine four different iodine species in aquatic systems (iodide, iodate and two organoiodine compounds: one of the organic species is chromatographically elutable from a column filled with an anion exchanger resin, the other one is not). The iodine species were analysed after the isotope dilution step with an enriched ¹²⁹I spike and after their chromatographic separation. The total iodine concentration was measured after decomposition of organic compounds in the aquatic system by UV irradiation. Different types of natural water samples (river water, water of a pond, moorland lake water) were analysed and important water parameters like pH-value, redox potential, oxygen content and dissolved organic carbon were measured for each of these samples. The total iodine concentration in the different samples differed only slightly in the range of 2-7 μg/l. In most of the moorland lake water samples only the two organoiodine species could be detected. In these samples the concentration of iodide and iodate was less than the detection limit of 0.5 μg/l and 0.1 μg/l, respectively. On the other hand, all four iodine species could be determined in most of the river water samples. Positive correlations were found for the oxygen content of the water samples and the iodate concentration as well as for the redox potential and the anionic organoiodine compound. (orig.)

[en] This review was presented as a plenary lecture at the International Symposium on Radioiodines. The chemical nature of iodinating species are reviewed with emphasis on biological iodinations and goitrogens. (author)

[en] Thirty radioisotopes of iodine are known but only those with mass numbers from 123 to 135 are of major radiotoxicological interest. Exposure of animals or man to inorganic ¹³¹I or ¹²⁵I may result in the induction of benign or malignant thyroid tumors or depression of thyroid function; Bq for Bq ¹²⁵I is less toxic than ¹³¹I. However, the shorter lived radioiodines ¹³²I, ¹³³I, and ¹³⁵I appear to be 10 to 100 times more toxic than ¹³¹I alone. Little information is available about the toxicity of radioiodine containing organic compounds. The DNA precursor, iododeoxyuridine when labelled with ¹²⁵I becomes incorporated into the cell nucleus and produces severe and often irreparable damage due to the emission of Auger electrons. The risk estimate for the induction of thyroid carcinoma or adenoma by inorganic ¹³¹I is considered to be 10 to 20x10^-6 persons Gy ^-1y^-1, but may be up to 100 times larger for persons exposed to mixtures of short-lived radioiodines. (author)