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Amyloid fibres attract considerable interests due to their biological roles in neurodegenerative diseases and their potentials as functional biomaterials. We describe here a completely new finding about an intrinsic signal of amyloid fibres in the near infrared (NIR) range. When combined with their recently reported blue luminescence, it paves the way toward new blueprints for label-free detections of amyloid deposits within in vitro up to in vivo contexts. The blue luminescence allows for staining-free characterization of amyloid deposits within human samples. The NIR signal offers promising prospects for innovative diagnostic strategies of neurodegenerative diseases; a need to improve medical care and to develop new therapies. As a proof of concept, we demonstrate direct detection of amyloid deposits within brains of living aged "Alzheimer's" mice using non-invasive and contrast agent-free imaging. UV-Vis-NIR optical properties of amyloids opens new research avenues across amyloidoses as well as for next generation biophotonic devices.

The cellular localization of inducible (iNOS) and constitutive (cNOS) nitric oxide synthase was studied in rats by immunocytochemical techniques involving specific iNOS and cNOS directed antibodies and by NADPH-diaphorase histochemistry. Paraformaldehyde-fixed vibratome sections of brains and cryostat sections of peripheral lymph nodes were studied of rats treated with endotoxin (2.5 micrograms/kg or 2.5 mg/kg i.v.), rats infected with rabies virus, and rats exposed to experimental allergic encephalomyelitis (EAE). Endotoxin-treated animals showed no appearance of immunoreactive iNOS (ir-iNOS) cells in the brain with the exception of a few microglial cells near the median eminence and some meningeal macrophages. In the same animals however, iNOS-immunoreactive cells were found in peripheral lymph nodes. Neurons that stain positive for cNOS and for NADPH-diaphorase could be observed in brains of control as well as of endotoxin-treated animals with a similar distribution and staining intensity. In contrast, animals that had been infected with rabies virus or subjected to EAE, showed the appearance of ir-iNOS-positive cells in several brain areas. These cells are located near blood vessels and lesion sites. The majority of these cells are GSA-I-B4 isolectin-positive and therefore are likely to represent macrophages. Our data suggest that increased production of nitric oxide may play a role in the altered brain functions in rabies-infected and EAE rats. On the contrary, increased nitric oxide production is probably not involved in the non-specific symptoms of sickness induced by endotoxin.

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It was concluded that the hypothalamus, hippocampus, thalamus and cortex react rapidly to peripheral irradiation by releasing pro-inflammatory mediators. The results also show that the vagus nerve is one of the major ascending pathways for rapid signalling to the brain with respect to partial body irradiation.