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Evidence for important roles of the highly reactive oxidant peroxynitrite in diabetic complications is emerging. We evaluated the role of peroxynitrite in early peripheral neuropathy and vascular dysfunction in STZ-diabetic rats. In the first dose-finding study, control and STZ-diabetic rats were maintained with or without the potent peroxynitrite decomposition catalyst Fe(III)tetrakis-2-(N-triethylene glycol monomethyl ether) pyridyl porphyrin (FP15) at 3, 5, or 10 mg x [kg.sup.-1] x [day.sup.-1] in the drinking water for 4 wk after an initial 2 wk without treatment for assessment of early neuropathy. In the second study with similar experimental design, control and STZ-diabetic rats were maintained with or without FP15, 5 mg x [kg.sup.-1] x [day.sup.-1], for vascular studies. Rats with 6-wk duration of diabetes developed motor and sensory nerve conduction velocity deficits, mechanical hyperalgesia, and tactile allodynia in the absence of small sensory nerve fiber degeneration. They also had increased nitrotyrosine and poly(ADP-ribose) immunofluorescence in the sciatic nerve and dorsal root ganglia. All these variables were dose-dependently corrected by FP15, with minimal differences between the 5 and 10 mg x [kg.sup.-1] x [day.sup.-1] doses. FP15, 5 mg x [kg.sup.-1] x [day.sup.-1], also corrected endoneurial nutritive blood flow and nitrotyrosine, but not superoxide, fluorescence in aorta and epineurial arterioles. Diabetes-induced decreases in acetylcholine-mediated relaxation by epineurial arterioles and coronary and mesenteric arteries, as well as bradykinin-induced relaxation by coronary and mesenteric arteries, were alleviated by FP15 treatment. The findings reveal the important role of nitrosative stress in early neuropathy and vasculopathy and provide the rationale for further studies of peroxynitrite decomposition catalysts in long-term diabetic models.

The mechanism of hydrocarbon hydroxylation mediated by polyhalogenated ruthenium porphyrin catalysts with 2,6-dichloropyridine N-oxide as the oxidant is reported. The analysis has shown that the Ru(II), Ru(IV), and Ru(VI) porphyrin species observed during catalysis act as a reservoir of catalyst precursors and the results have supported a Ru(III)-oxoRu(V) cycle for the 'fast catalysis'.

The formation of both radical and cation intermediates during the hydroxylations of diagnostic hydrocarbon substrate probes by T4moH is implicated. The results present a divergence of radical and cation pathways for T4-moH-mediated hydroxylation that can be dissected by diagnostic substrate probe rearrangements and by changes in the source of oxygen used for substrate oxygenation.

A new general synthesis of the citrate-based siderophores acinetoferrin (Af) and schizokinen (Sz) and their analogues is described. The molecular structure of gallium schizokinen was determined by (super 1)H NMR spectroscopy.