
J. M. MENTER ET AL. 161
quences. Although the consequences of these interactions
are not well known with respect to keloids, one might
gain insight by considering the closely-related case of
systemic sclerosis, where imbalances in NO metabolism,
type I collagen expression, and the occurrence of nitrated
proteins have been known to occur for certain disease
states [24-26]. Melanin sequestration of NO and its role
in generating toxic NOx might have similar effects on
normal fibroblasts that could possibly result in their
transformation to keloid fibroblasts. This latter question
is currently under investigation in our laboratory (Nok-
kaew et al., in progress).
5. Conclusions
a) Sepia melanin accelerates (couples) the oxidation of
NO to NOx and the reduction of molecular O2 in buffered
aqueous solution.
b) The reaction kinetics fit well to a simple Langmuir
adsorption isotherm, and the reaction therefore appears to
take place between adsorbed NO and O2 via a chemi-
sorption mechanism. We obtained a value of pseudo first
order constant 7
8.2 10 sk1
and adsorption
coefficient Kad = 4.04 M1.
c) Such a reaction occurring in situ in dermal tissue
might have significant epigenetic consequences in keloid
formation or related pathologies.
6. Acknowledgements
This work was funded in part by GRANTS: MBRS
#GM08248, RCMI #8G12MD007602, and DOD # 911
NF-10-1 0448. There are no conflicts of interest.
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