Synthesis and mass spectrometric fragmentation characteristics of imidazole ribosides-analogs of intermediates of purine de novo synthetic pathway.

Two inherited deficiencies have been described in purine de novo synthesis pathway. Both the defects are diagnosed by detecting ribosides--dephosphorylated substrates of the enzymes--in patient's urine. We describe here a synthesis and mass spectrometric fragmentation of ribosides potentially of diagnostic importance for defects in the second part of the pathway. All the species, except 5-amino-4-imidazolesuccinocarboxamideriboside can be synthesized from the commercially available 5-amino-4-imidazolecarboxamideriboside by chemical methods. Fragmentation spectra of the compounds were obtained by the ion trap mass spectrometry. During fragmentation an opening of the imidazole ring was not observed for any of the compounds but loss of its substituents in the form of small molecules (NH3, CO2, CO) is the major route of fragmentation. The ribose moiety cleaves off molecule(s) of water, undergoes a cross-ring cleavage or breaks away as a whole.

[Changes in cellular immunity in children with acute laryngitis]. / Zmeny v bunecné imunite u detí s akutní laryngitidou.

In 46 children with acute laryngitis the authors tested the state of cellular immunity in the acute stage and repeatedly during controls after 1-3-month intervals. They assessed the number of total T lymphocytes and active T lymphocytes, the number of B lymphocytes and by means of the test of blastic transformation they obtained information on the functional fitness of the T lymphocyte population. They revealed important changes in the state of the T lymphocyte population, i.e. quantitative as well as functional changes which persisted in 80% of the children 1 and a half months after the acute state. This finding must be considered the consequence of viral infection potentiated by corticoids which may be the cause of prolonged morbidity of these children. It is not advisable to admit these children to child communities. In case of repeated respiratory diseases it is recommended to make an immunological examination and apply immunomodulating therapy in immunodeficiencies.