EXAMINING THE ROLE OF THE NITRIC OXID SYSTEM AS THE ESSENTIAL PATHOGENETIC LINK IN STEVENS-JOHNSON SYNDROME

, , , , The aim: To determine a possible role of nitric oxide system as one of the pathogenesis links in Stevens-Johnson syndrome depending on the severity of disease progression. Material and methods: We examined 11 patients with Stevens-Johnson syndrome. The function of nitric oxide system (NO - NOS) in blood serum was examined. Results: During the study of nitric oxide system (NO-NOS) in patients with SJS, it was observed that NO2¯ level was increased by 1.53 times, NO3¯ level – by 3.33 times, activity of total NOS – by 5.78 times, constitutive (cNOS) – by 1.81 times and inducible (iNOS) – by 13.36 times. Conclusions: The intensity of nitric oxide system function was studied in patients with Stevens-Johnson syndrome and dependence of changes of its parameters from the clinical signs of disease was detected. It was found that the determination of nitrite and nitrate anion levels in blood serum can be used for the purpose of predicting the disease course and choosing the therapy methods for the patients with SJS.

An eutherian intronic sequence gave rise to a major satellite DNA in Platyrrhini

Satellite DNAs (satDNAs) are major components of eukaryote genomes. However, because of their quick divergence, the evolutionary origin of a given satDNA family can rarely be determined. Herein we took advantage of available primate sequenced genomes to determine the origin of the CapA satDNA (~1,500 bp long monomers), first described in Sapajus apella. We show that CapA is an abundant satDNA in Platyrrhini, whereas in the genomes of most eutherian mammals, including humans, this sequence is present only as a single copy located within a large intron of the NOS1AP (nitric oxid synthase 1 adaptor protein) Gene. Our data suggest that this intronic CapA-like sequence gave rise to the CapA satDNA and we discuss possible mechanisms implicated in this event. This is the first report of a single copy intronic sequence giving origin to a satDNA that reaches up to 100,000 copies in some genomes.

Useful and harmful effects of nitric oxide

In living sistems synthesis of nitric oxide occurs during metabolism from Larginin, nitrite and ascorbate. Being very significant carrier of information within numerous both physiological and pathological proceses in mammals' organisms, nitric oxid could possibly be useful as well as harmful. Nitric oxide synthesis is adjuvant in a healthy organism because it represents the basic molecule for understanding numerous processes in neurology, psychology, immunology and varios related fields. In other words, nitric oxide participate in number of physiological processes, such as: transmission of nerve signals (neurotransmitter role), regulation of smooth muscle tissue relaxation (eg. vasodilatation), peristaltic movements, immunomodulation, mastocyte activation, development of inflammatory response, apoptosis regulation, angiogenesis and glucose metabolism, normal heart functioning and antioxidation role. Besides being useful, nitric oxide can be harmful as well, because it has one unpaired electron, so consequently it is susceptible to oxidation becoming a stable free radical. Being such, it reacts quickly with superoxide-anion radical, givind at first an extremely reactive peroxinitrite anion, and subsequently peroxidnitrite acid. This acid is very dangerous causing thiol groups oxidation, tyrosine and phenylalanine nitrosylation, lipid oxidation, DNK chain splitting, nitrification and nucleic bases deamination. These damages of macromolecules can cause a series of undesirable changes which subsequently distub functions of molecules, and thus of cells, tissues and even organs.