Nitric oxide (NO) is a small, diffusible free radical that is generated from L-arginine by a family of enzymes, collectively termed the nitric oxide synthases. We investigated the role of NO in tendon healing. NO synthase activity and immunoreactivity was absent in un-injured rat Achilles tendon. After surgical division there was a five-fold increase in NO synthase activity and immunoreactivity within the healing tendon at day 7, with a return to near baseline levels at day 14. Inhibition of NO synthase activity with oral administration of N omega-nitro-L-arginine methyl ester (L-NAME) resulted in a significant reduction in cross-sectional area (30% at day 7, p < 0.01, 50% at day 15, p < 0.001) and failure load (24% at day 7, p < 0.01) of the healing Achilles tendon constructs. Rats fed the same regimen of the enantiomer of L-NAME, (D-NAME) had normal tendon healing. These results indicate that nitric oxide synthase is induced during tendon healing and inhibition of nitric oxide synthase inhibits this tendon healing.

PbI2 crystals have been intercalated with ammonia, methylamine (CH3NH2), ethylamine (C2H5NH2), and butylamine (C4H9NH2) for the first time. Raman spectra of these materials, and also of PbI2 intercalated with nonylamine (C9H19NH2) were obtained using an excitation wavelength of 514.531 nm. For comparison a study of the interaction of CdI2 with the same molecules is included. Raman spectroscopy in the range 10-500 cm-1 demonstrated the occurrence of a polytypic phase transition from 1 T to 3 T on intercalation of PbI2 and also that intercalation results in the breaking up of the crystal into many small crystallites. The existence of strong Pb-N interactions was demonstrated by both infrared and Raman spectroscopy.

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