Chemical modification of the eremomycin antibiotic. Formation of a cyclic covalent dimer.
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Biomedical subjects
Publications and source records attributed to A Koncz.
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Previous studies showed that some lactones have beta-lactamase inhibitory or antibacterial effects, others--like A-factor (a gamma-butyrolactone) and its derivatives--stimulate sporulation in Streptomyces griseus strains. Our experiments were aimed at exploring whether synthetic gamma-lactones had such effects. None of the seven gamma-lactones studied showed antibacterial activity, but two of them inhibited beta-lactamases isolated from various bacteria. These two gamma-lactones did not reduce colony formation of murine bone marrow cells in vitro, indicating that they were not toxic to proliferating mammalian cells. Four gamma-lactones, including the two inhibiting beta-lactamase, stimulated sporulation in the non-sporulating S. griseus bald 7 mutant. Further studies of gamma-lactones as potential inhibitors of beta-lactamase seem to be warranted.
The cell distribution and function of alveolar macrophages and T lymphocytes were investigated in the bronchoalveolar lavage (BAL) of 15 patients with systemic sclerosis (SSc). In alveolar macrophages, both spontaneous and PMA-stimulated TNF-alpha production were increased in SSc. PMA-induced IL-6 production was also elevated. Spontaneous IL-6 excretion of scleroderma alveolar macrophages was similar to the controls. Yeast and C3b-coated yeast (opsonised yeast) phagocytosis, chemotaxis and Fc receptor activity of alveolar macrophages were normal. The proportion of CD3, CD4 and CD8 T-lymphocyte subsets in the BAL was similar to the control values. The lymphocyte blast transformation index of the non-adherent cells deriving from the BAL fluid was markedly decreased.
Acylation of amoxycillin and cephalexin with acids III, V and VII, and with isocyanate VIII furnished the corresponding beta-lactam antibiotics (X and XIII-XV, respectively). The antibacterial activity of these new antibiotic analogues against Helicobacter pylori was found to be identical with those of amoxycillin, Augmentin, erythromycin and ciprofloxacin.
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