Hippuran-123I: Preparation and quality control

A kit-like procedure is described for the labelling of Hippuran by exchange in a melt with carrier-free iodide-123 directly formed from the decay of¹²³Xe. Decay and subsequent melting for 15 min at 180°C are performed in one and the same ampoule. This results in a transfer of 95% of the¹²³I-activity into Hippuran with a residual¹²³I-content of <1.0%. Quality control is based on thin-layer chromatography. Contaminants are discussed and a comparison is made with commercial preparations of Hippuran-¹³¹I.     

Evidence for the reaction of a long-lived monotypic species of iodine in the gas phase

A monotypic long-lived radioactive iodine of¹²³I or¹²⁵I resulting from the¹²³I or¹²⁵Xe(EC)¹²⁵I nuclear transformation, respectively, is described. The iodine species has the characteristics thought peculiar to the hydrated halogen that participates in certain concerted termolecular halogen-halogen reactions. The reaction leading to¹²³ICl or¹²⁵ICl in gas phase substrates of Cl₂, NOCl, HCl and CCl₄ was studied. Deceased, visiting scientist during 1972 from the Institute of Atomic Physics, Bucharest. Romania.     

Iodination of lactate dehydrogenase isoenzymes using radioactive and inactive iodine

The iodination of lactate dehydrogenase isoenzymes which has not been attempted so far has been performed using radioactive and inactive iodine. A new method for the determination of trace amounts of protein-bound iodine in the range of 10–100 μg has been developed. Out of two methods employed for iodination, chloramine-T method was found to be superior to the lactoperoxidase method for iodination with both radioactive and inactive iodine. It was found that the amount of iodinated LDH formed during iodination depends on the amount of LDH and of the reagents used for iodination. Completely purified LHD-1 and LDH-2 isoenzymes were iodinated using both inactive and radioactive iodine. The iodinated isoenzymes were separated from the unreacted iodide by gel permeation chromatography using Sephadex G-75-120 column. The ratio of radioiodinated LDH to unreacted¹²⁵I was largest (3.72) when the amount of LDH used was 4.54 μg. The specific activity obtained when iodination was carried out under optimum conditions was 238 μCi/μg. No radiation damage for the radioiodinated LDH was observed when it is kept for as long as two weeks after iodination.     

Kinetics of 17-(123I) iodoheptadecanoic acid in myocardium of rats

Myocardial uptake and turnover of 17-(¹²³I)-iodoheptadecanoic acid, injected i.v., was studied in rats. Kinetics of radioactivity incorporated into myocardial tissue and heart lipids as well as myocardial radioactivity recovered as¹²³I iodide were determined. Maximal heart uptake of IHA (7.9% dose/g heart) was observed as early as 30 sec., p.i., followed by mono-component elimination period. Already 10 to 30 sec p.i. 70 to 80% of total myocardial radioactivity was recovered as¹²³I iodide. IHA was incorporated only in modest amounts into myocardial phospholipids and triglycerides. Time course of total myocardial radioactivity grossly paralleled that recovered as¹²³I iodide. These findings indicate stringent limitations in utility of IHA as a tracer for assessment of β-oxidation.     

123I production at the Milan AVF cyclotron

The production of¹²³I from enriched¹²⁴Te is described. Preliminary experiments on a distillation separation of iodine from the Te target have been performed and the method seems promising in comparison to the time-consuming chemical separation technique.     

Studies on the234U and238U ratio in natural materials

With the use of an 80 MeV isochronous cyclotron, a preparation procedure for¹²³I is outlined. The nuclear reaction applied in the process is: $$^{127} I\left( {p,5n} \right)^{123} Xe\xrightarrow[{2.1h}]{{\beta ^ + CE}}^{123} I$$ A liquid target is irradiated and a continuous gas-liquid extraction of parent¹²³Xe is performed. After a short growth time the daughter¹²³I is dissolved and treated for various applications. The radionuclidic purity is very high, only¹²⁵I is detectable with a maximum of 0.2% to the end of the preparation process. In this production of carrier-free¹²³Xe and¹²³I, the major chemical problem consists of a separation into microquantities. Attempts to find a solution to various technical problems are also described.     

The Photochemistry of Ch3I in Various Matrices at Low Temperature

The photodissociation of methyl iodide in various matrices at low temperature was studied. The observed Raman spectra excited by 514.5 nm laser radiation showed that there were two different photolytically produced iodine species isolated in the matrices after illumination by a medium pressure mercury lamp. One species which was dominant at lower iodine concentrations and exhibited a progression with an ωe of 201 cm^?1, belonged to the matrix isolated iodine monomer (I₂). The other species, which was dominant at higher iodine concentrations with an ω_e of approximately 180 cm^?1, belonged to the iodine aggregate ((I₂)_n). Five progressions of resonance Raman or resonance fluorescence of these two species were also observed in the other matrices. The iodine aggregate in the methyl iodide matrix at 77 K was formed in a crystalline structure, while the photolytically generated iodine aggregate from CH₃I/Ar (2/3) matrix at 10 K, after illumination with a mercury lamp, was in amorphous form. The rearrangement of photolytically produced iodine aggregate in methyl iodide matrix was observed as a function of the duration of illumination. Local heating effects of the laser radiation might induce the iodine monomer to aggregate in matrices. The photodissociation mechanism of methyl iodide in matrices is also proposed.     

A condition variation study for radioiodination via triazene intermediates

Pyrrolidyl triazenes prepared by interception of the diazonium transient in the Sandmeyer reaction of amines can serve as useful intermediates in the iodination and radioiodination of aryl rings. Decomposition of such triazenes in the presence of iodide is acid-catalyzed and is sensitive to choice of solvent, acid, and triazene structure. A condition variation study by HPLC of four different solvent systems and two non-nucleophilic acids was carried out on the¹²³I iodination of the triazenes of p-nitroaniline, p-anisidine and p-toluidine. This method has proven useful in radiolabeling of two pharmaceutical analogs which were not amenable to labeling through the classic Sandmeyer method.     

Isotope exchange of iodine between sodium iodide [Na131I] and [4-127I]iodoantipyrine via organic medium

The present investigation deals with a study of the isotope exchange reaction of iodine between sodium iodide [Na¹³¹I] and [4-¹²⁷I]iodoantipyrine in organic medium, using different iodinating radioiodine reagents of different carrier-iodine concentration. A maximum saturation yield over 90% of pure [4-¹³¹I]iodoantipyrine has been obtained by performing the isotope exchange reaction in ethanol at 80°C in 30 min. The same yield has been obtained using the same concentrations by performing the reaction at room temperature (17–20°C) for 3 h. Also the rate of the isotope exchange reaction was found to be carrier-iodine dependent as well as time and temperature dependent. According to these results and reaction conditions, a kit form method was elaborated for the synthesis of [4-¹³¹I]iodoantipyrine as well as [4-¹²³I]iodoantipyrine.     

Kinetics of the Rapid Base Catalyzed Iodination of Imidazole and 2‐Methylimidazole by Molecular Iodine in Aqueous Medium: pH Effect

The second‐order kinetics of iodination of imidazole and 2‐methylimidazole in aqueous medium at various pH values and temperatures are studied in the presence and absence of a base catalyst. The reactions being electrophilic substitutions, molecular iodine is the sole iodinating agent, as the reactant solutions used are totally devoid of I ^? ions. The specific reaction rates of imidazole ( I ) and 2‐methylimidazole ( II ) for the catalyzed reactions are found to be 87.00 and 62.92 M^?1 s^?1 at 27.0°C, respectively, at 7.0 pH. The base component of the buffer used to maintain the pH catalyzes the reactions. The rapidity of the reactions necessitates the use of a rotating platinum electrode to follow the decay of the unreacted iodine. The study provides a quantitative verification of the reactivities of the substrates.     

Development of a process for routine production of123I using the127I(p, 5n)123Xe→123I reaction

The object of this paper is to give details of a production method for¹²³I, now in routine use at Harwell. We employ the (p, 5n) reaction, irradiating a liquid target of di-iodomethane (CH₂I₂) spiked with additional iodine, with 58 MeV protons. A yield of ∼9 mCi/μAh is obtained; the only detectable radionuclidic impurity is¹²⁵I, present to the extent of ∼0.15% by activity at the time of separation of Xe from I.     

Excitation functions of proton-induced nuclear reactions on124Xe: Production of123I

Highy enriched gaseous¹²⁴Xe /99.9%/ is used to perform instrumental measurements of excitation functions of the¹²⁴Xe/p, 2n/¹²³Cs and¹²⁴Xe/p, pn/¹²³Xe reactions up to the proton energy of 33 MeV. Differential and integral yields of¹²³I have also been determined /6.6 h after irradiation/.     

Electrochemistry of iodine and iodide in chloroaluminate melts

The electrochemical behavior of iodine and iodide has been studied in AlCl₃+NaCl mixtures with compositions ranging from NaCl saturated melts to AlCl₃+NaCl (63+37 mol %) at platinum and tungsten electrodes. Iodide is oxidized in two steps to iodine and I(I); a reduction wave to iodide and an oxidation wave to I(I) are obtained in iodine solutions. The equilibrium constant for the reaction, I^?+I(I)=I₂, is 6×10⁸ l mol^?1 in molten chloroaluminate melts at 175°C.     

Degradation of 81 keV <Superscript>133</Superscript>Xe gamma-rays into the 31 keV X-ray peak in CsI scintillators

Pacific Northwest National Laboratory uses beta-gamma coincidence detectors in a number of xenon sampling and measurement systems to enable simultaneous, sensitive measurements of ¹³¹Xe, ¹³³Xe, ^133mXe, and ¹³⁵Xe for treaty monitoring applications. In recent years, a new style of beta–gamma detector was developed to improve upon the detector module used in the Automated Radioxenon Sampler/Analyzer. The results of an MCNP5 Monte Carlo simulation of the new detector cell are presented, with particular emphasis on the identification of an energy deposition sequence with the potential to introduce significant error into the detector efficiency calibration. This sequence occurs when an 81 keV gamma from ¹³³Xe is absorbed in an inactive region of the CsI(Na) scintillator, followed by emission of a 31 keV X-ray from cesium (or possibly a 28.5 keV X-ray from iodine). These X-rays add excess counts into the 31 keV peak observed in the decay of ¹³³Xe. The impact of this effect on different efficiency calibration techniques is discussed.     

Changes in the secondary structure of proteins labeled with <Superscript>125</Superscript>I: CD spectroscopy and enzymatic activity studies

Summary Bovine serum albumin (BSA) and lysozyme (LSZ) were radiolabeled with ¹²⁵I. Three different methods for protein iodination with ¹²⁵I were optimized. Parameters like incubation time and ratio of oxidizing agent and amount of protein were established. During protein iodination with ¹²⁵I, structural damages caused by the introduction of iodine into the protein may occur. These damages depend on the oxidizing agent used and may lead to considerable changes in the protein structure and, hence, their biological activity. Changes in secondary structure of LSZ and BSA were examined by circular dichroism (CD). Enzymatic activity tests were performed with lysozyme to check its biological activity. The Iodo Bead was found the best oxidizing agent for protein iodination.     

Chemical processing of 123I with a modified Bio-Rex 5 resin

The Bio-Rex 5 resin was used for the recovery of ¹²³I, producedin a cyclotron by irradiation of a ¹²⁴ Xe target. Initially fouranion exchange resins AG1-X8, AG2-X8, Amberlite IRA-93 and Bio-Rex 5 wereused, but none of them gave good separations. Bio-Rex 5, consisting of a largeportion of tertiary and a smaller portion of quaternary amino groups, wasthen modified so that the resin contained only tertiary amine functional groupsand this modified resin was used for the separation. The concentrations ofiodide solutions were ca 5 ppb and the volumes about 120 ml. For measurementof iodide, ¹³¹I was added as tracer. In this study 6 columns ofvarious sizes were used and the best of them, in terms of maximum recoveryand minimum volume of NaOH for elution, was selected for routine production.     

(Perhalogenmethylthio)heterocyclen. XVIII . Synthese und eigenschaften von halogenierten (perhalogenmethylthio)pyrrolen

(Trifluoromethyltho)pyrroles 1-5 and (chlorodifluoromethylthio)pyrroles 6 were chlorinated by sulfuryl chloride, sulfuryl chloride/silicon dioxide, sulfuryl chloride/disulfur dichloried/aluminium trichloried to give the corresponding chloropyrroles 1a-d , 2a,b , 3a,b , 4a , 5a , and 6a-c Bromination with bromine or iodination with iodine/potassium iodide of 2, 3, 4 , and 6 yielded the derivatives 2c,d, 3c,d, 4b, 6d , and 2e, 3e, f, 4c , 6e respectively. Mixed halogenated pyrroles 3g and h were obtained from 3a and bromne or 3a and iodine/potassium iodide. During some chlorination reactions 7, 8 , and 9 were fromed in low yield asbyproducts. The ¹H-nmr, ¹⁹F-nmr and ir spectroscopic data are presented.     

133Xe gas release during irradiation of uranium metal in the presence of air

Uranium metal samples of large surface to volume ratios were irradiated in the presence of 1 cm³ of air. It was found that 1.708±0.015% of¹³³Xe was released during irradiation. It was proved that this amount of¹³³Xe is due to the decay of¹³³I originally released. The release of¹³³Xe was attributed to the knock-out mechanism.     

Tracer experiments for the determination of chemical forms of radioiodine in water samples

Two simple methods, (1) isotope exchange method and (2) anion exchanger column method, are developed for the determination of chemical forms of radioiodine (iodide and iodate) in water samples. Using these methods, transformations of chemical forms of iodine in various water samples were studied. It was observed that iodate in rain water (unfiltered) and milk tended to change iodide form, whereas iodide was converted to iodate form in seawater and tap water. After the Chernobyl accident both chemical forms of¹³¹I (iodide and iodate) were found in rain water samples collected in Japan.     

Investigation on the iodination reaction of methylene blue by liquid chromatography-mass spectrometry with ionspray ionisation.

Radioactive iodine (131I and 123I) labelled methylene blue is used for the early diagnosis of melanoma metastases. We studied the iodination reaction of methylene blue (using "cold" iodine) in order to characterise the iodination product(s) as far as number and position of iodine atoms introduced on the aromatic ring(s) is concerned. The reaction was carried out under the same experimental conditions used for the radioactive one, that is in a large excess of methylene blue. The ionspray HPLC-MS analysis of the reaction mixture showed that the iodinated methylene blue was present only in a very small amount and the main iodinated product was a demethylated one, coming out from the iodination of an impurity azure B. We also studied the iodination reaction of azure B in order to better explain the reaction pathway. Commercial azure B contains impurities of methylene blue and all the possible demethylated derivatives. HPLC-MS analysis of the reaction mixture allowed a complete characterisation of the iodinated and bis-iodinated products.