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Samples of l-[ S-methyl-C]methionine prepared by on-column [C]methylation on a C18 cartridge were analyzed by HPLC under different conditions in order to explain some anomalies observed in the UV-chromatograms. By so doing, two new unlabelled impurities were found and identified as iodide and homocystine. Their amounts are still compatible with the safe human use of the radiotracer solution. Nevertheless, if needed, iodide can be totally removed by elution through an anion-exchange resin, while homocystine can be reduced by either decreasing the amount of precursor used in the synthesis or preventing its air oxidation. [ABSTRACT FROM AUTHOR]

Comments on a study on the immunogenecity and safety of virosomal vaccine in HIV-infected children. Determination of serum antihaemagglutinin antibody titres; Definition of seroconversion.

Introduction: The incidence of melanoma increased considerably in recent decades, representing a significant public health problem. We aimed to evaluate the ability of non-specialists for the preliminary screening of skin lesions to identify melanoma-suspect lesions., Materials and Methods: A medical student and a dermatologist specialist examined the total body scans of 50 patients., Results: The agreement between the expert and the non-specialist was 87.75% (κ = 0.65) regarding the assessment of clinical significance. The four parameters of the ABCD rule were evaluated on the 129 lesions rated as clinically significant by both observers. Asymmetry was evaluated similarly in 79.9% (κ = 0.59), irregular borders in 74.4% (κ = 0.50), color in 81.4% (κ = 0.57), and diameter in 89.9% (κ = 0.77) of the cases. The concordance of the two groups was 96.9% (κ = 0.83) in the case of the detection of the Ugly Duckling Sign., Conclusions: Although the involvement of GPs is part of routine care worldwide, emphasizing the importance of educating medical students and general practitioners is crucial, as many European countries lack structured melanoma screening training programs targeting non-dermatologists.

By adapting previously reported reaction conditions, [ 18 F]FMISO was synthesized using a TracerLab FX-FDG module in 31 min from no carrier added [ 18 F]fluoride in 56% radiochemical yield. A novel and simple purification setup based on disposable cartridges was developed allowing the radiopharmaceutical to be obtained in high radiochemical purity (>99.5%) and with chemical impurities far below the Ph.Eur.'s thresholds. Moreover, the study pinpointed some shortcomings of the high-performance liquid chromatography (HPLC) method reported in the dedicated Ph.Eur's monograph., (© 2021 John Wiley & Sons, Ltd.)

Tetrabutylammonium is a phase-transfer agent commonly used in PET radiochemistry. Its toxicity makes its quantification mandatory. However, the official HPLC method for tetrabutylammonium analysis reported in the European Pharmacopoeia (Ph. Eur.) apparently fails to achieve the described separation in most new generation reverse-phase columns. The study highlights the differences in separation achievable by varying some of the chromatographic conditions, such as temperature, eluent composition and ion-pairing agent concentration. In the end, variations to the method within the limits allowed by the Ph. Eur. were not sufficient to overcome the problem, thus forcing to a more radical change of the organic component of the mobile phase., (© 2019 John Wiley & Sons, Ltd.)

Background: The purpose of this study was to rank the risk factors for dental caries among first-year university students in Nice (France)., Methods: All first-year students are required to undergo a compulsory preventive medical examination. Among these students, volunteers were offered a dental visit. Information was collected through an interview followed by an oral examination. We assessed the volunteers' oral hygiene habits (daily toothbrushing frequency, type of toothbrush used, frequency of toothbrush replacement, place of toothpaste purchase, and flossing), daily health-related behaviors (number of main daily meals, daily sugary intakes, smoking, alcohol consumption, consumption of cannabis or other drugs), oral-health-related behaviors (self-reported oral health, dental visits during the past year, reason for the last dental consultation, and failure to seek dental care due to financial reasons), and oral health issues (dental crowding, oral hygiene, presence of caries, presence of pit and fissure sealant remnants). The dependent variable was the presence of at least one untreated carious lesion. The data were subjected to univariate analyses to select explanatory variables, and subsequently, a logistic regression was performed., Results: Six hundred twenty-nine students aged 18.8±1.6 years were enrolled in this study. The sex ratio was 0.72, with a strong predominance of the female gender. Only 59.3% of the students had never experienced dental caries, while 22.4% had already undergone restorative procedures and did not have any carious lesion at the time of the examination, and 11.6% presented with carious lesions and had never been treated by a dentist. Lastly, 6.7% had carious lesions despite evidence of prior restorative procedures. The multivariate analysis revealed the following pejorative risk factors: failure to seek dental care due to financial reasons (OR:3.06, 95% CI: 1.40-6.70), poor oral hygiene revealed during the oral examination (OR:2.59, 95% CI: 1.60-4.20), and poor self-reported oral health (OR:2.43, 95% CI: 1.24-4.77). Conversely, the analysis revealed the following protective factors: preventive visits to the dentist (OR:0.63, 95% CI: 0.41-0.99), the use of an electric toothbrush (OR:0.36, 95% CI: 0.17-0.77), and sealant remnants (OR:0.22, 95% CI: 0.05-0.97)., Conclusions: The highest-ranking caries risk factor for the study population was the financial barrier.

Introduction: 3'-Deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) shows great potential as a tracer for proliferative studies with PET. However, its regular application is often limited by low radiochemical yields and the use of a troublesome HPLC separation. Moreover, a high content of ethanol, at least one-fold higher than the European Pharmacopoeia and US Pharmacopoeia's established limit, is always present in the final product. The present study reports an optimization of the reaction conditions and a simple and straightforward purification step which affords a solution of [(18)F]FLT suitable for human use., Methods: Several conditions and materials were tested for both the nucleophilic substitution and purification step. The latter was achieved by means of a series of commercial solid-phase extraction cartridges. Very conveniently, the whole one-pot synthesis was carried out on commercial automated modules using basically the same setup employed for the synthesis of [(18)F]FDG., Results: Under routine conditions, radiochemical yields of 37% [decay-corrected to start of synthesis (SOS)] were achieved in ca. 39 min from SOS, with radiochemical purities >98% (usually >99%). The negligible radiolysis observed could be easily suppressed by adding 0.5% of EtOH. Typical unlabelled chemical impurities detected were thymidine (0.15 ppm), thymine (0.28 ppm) and stavudine (0.05 ppm)., Conclusions: A reliable, simple and efficient preparation of [(18)F]FLT has been developed, able to afford an ethanol-free solution of the tracer with no need for any HPLC purification. Because of its similarity to the [(18)F]FDG synthesis, the method can be readily implemented on basically all the commercial modules developed for this common radiotracer., (Copyright © 2012 Elsevier Inc. All rights reserved.)