Biologic drugs represent a substantial progress in the treatment of chronic
inflammatory immunologic diseases. However, its crescent use has revealed seldom
reported or unknown adverse reactions, mainly associated with anti-tumor
necrosis factor (anti-TNF). Psoriasiform cutaneous reactions and few cases of
alopecia can occur in some patients while taking these drugs. Two cases of
alopecia were reported after anti-TNF therapy. Both also developed psoriasiform
lesions on the body. This is the second report about a new entity described as
'anti-TNF therapy-related alopecia', which combines clinical and
histopathological features of both alopecia areata and psoriatic alopecia. The
recognition of these effects by specialists is essential for the proper
management and guidance of these patients.
The rate of S-nitrosocysteine decomposition in a pH range between 0.7 < pH < 13 exhibits first- and second-order dependence on total cysteine concentration. The second-order term is only observed for pH values between 6.9 < pH < 12. Both first- and second-order terms show a complex dependence on the acidity of the medium. They increase with increasing pH, reaching a maximum value around pH = 8 and then decrease with further increase in pH. An analysis of the reaction products reveals the absence of nitrite ion and ammonia. No evidence of catalysis by copper ions is observed. These results suggest the existence of a new decomposition pathway for S-nitrosocysteine, which proceeds via an intramolecular nitroso group transfer producing a primary N-nitrosamine that decomposes rapidly to give the corresponding diazonium salt. The nitroso group transfer reaction occurs intermolecularly for the decomposition pathway exhibiting a quadratic dependence on cysteine concentration. Both nitroso group transfer pathways are subject to acid catalysis by cysteine. Kinetic results indicate that the extent of S...NO bond cleavage in the transition state is ahead of protonation of the AH...S sulfur atom. The results obtained show the existence of a new decomposition pathway for the S-nitrosocysteine where NO is not released, and hence, it has a significant biological impact due to the potential use of nitrosothiols as NO donors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.