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Biomedical subjects

A Mohacsi

Publications and source records attributed to A Mohacsi.

2 recordsLinked to original sources

Effects of synthesized elastin peptides on human leukocytes.

It is well demonstrated that various peptides derived from elastin are biologically active. The hexapeptide (Val-Gly-Val-Ala-Pro-Gly; VI) as well as elastin peptides were demonstrated to be chemotactic for fibroblasts, while kappa-elastin had marked biological effects on human PMNLs. The aim of our present work was to synthesize various elastin peptides and compare their action to that of kappa-elastin and this hexapeptide. The results indicate that the hexapeptide (Val-Gly-Val-Ala-Pro-Gly) and the two other synthesized hexapeptides (Pro-Gly-Val-Gly-Val-Ala; III and Val-Gly-Val-Gly-Val-Ala; IV) had very similar and specific effects on intracellular free calcium metabolism, on superoxide anion production and elastase release. The other peptides had no effects on these parameters, except a tripeptide (Val-Gly-Val; V) on superoxide anion production. Moreover, the effect of the hexapeptides (III and VI) could be abolished by Pertussis toxin preincubation. All peptides had very similar stimulating effects on H2O2 production and myeloperoxidase release. We conclude that most probably the peptide size and conformation, as well as peptide composition play a role in the biological effects of these peptides, through specific receptors on PMNLs surface.

Amino Acid Sequence↗

Transmembrane signaling changes with aging.

Altered immune response and transmembrane signaling with aging has previously been demonstrated. The aim of the present study was to characterize PMNLs and lymphocyte G proteins and to determine whether their relative amounts are altered with aging. First we studied the effects of FMLP on PMNLs IP3 formation. It was found that in any group of elderly the PMNLs IP3 formation was significantly decreased compared to that of young subjects. In FMLP receptor binding affinity no measurable difference exists in either low- or high-affinity FMLP receptors. The autoradiogram of 32P-ADP-ribosylated proteins by CT in lymphocytes of young individuals showed a major polypeptide of 40 kDa, and two much less prevalent components of 52 and 45 kDa. In contrast, in lymphocytes of elderly subjects the major polypeptide was 45 kDa, and the two others were very weakly labeled. In PMNLs, CT labeled the 45-kDa band quite strongly, mainly in the elderly, and the 52- and 40-kDa bands were very weakly labeled, mainly in young subjects. When PT was used, no age-related pattern changes could be demonstrated, while differences could be observed between the two types of cells.

Adenosine Diphosphate Ribose↗