Parenchymal and vascular lesions in ageing equine brains: histological and immunohistochemical studies.

Many age-related changes are described in the nervous system of different species, but detailed studies of brain lesions in ageing horses are lacking. The aim of the present study was to systematically characterize lesions in the brains of 60 horses aged from 7 to 23 years. No gross changes were present in any brain. Microscopically, spongiform changes, lipofuscin storage, corpora amylacea, gliosis and satellitosis were common, together with axonal and neuronal swellings. The most important findings were the presence of pseudocalcium-calcium (pCa-Ca) deposits and arterial wall degeneration. Scanning electron microscopical examination of two cases with vascular mineralization revealed marked deposition of an amorphous substance in the vessel walls that was probably formed by a polyanionic protein matrix and a mineral component. Immunohistochemically, numerous axonal spheroids were positively labelled for ubiquitin. No PrPsc was detected in sections with neuronal vacuolation. Neuronal swelling, corpora amylacea, hippocampal Tau-positive neurons and methenamine-positive diffuse (preamyloid) plaques were also detected. Congo red staining failed to detect amyloid deposition. The characterization of age-related lesions in the brains of these horses will allow these changes to be discriminated from pathological processes in future studies. Some lesions described here, including some vascular changes, the presence of diffuse plaques and tau accumulation in hippocampal neurons, have not been described previously in the horse.

Application of true color X-ray vision for electron microscopy in fired bullets and gunshot residue investigation

An X-ray color imaging system was used to study primer particles and fired bullets from different .22 rimfire ammunition. The technique proved to be very useful, allowing a ready, concomitant analysis of the morphology of primer particles and their elemental composition. The investigation of the bottom of fired bullets showed that antimony present in the bullet alloy is not evenly distributed, but organized in plates made up of almost pure antimony. Moreover, particles and other traces adherent to lead bottomed bullets containing elements different from lead, therefore, useful to the understanding of primer composition are readily and easily detected.

Dermal surface morphology in wound healing. An experimental scanning electron microscope study.

The authors observed, with a scanning electron microscope, the dermal surfaces of experimental wounds, following the enzymatic digestion with trypsin of the dermo-epidermal junction. Cut lesions showed an early reconstitution of the basement membrane and progressive convergence of the margins. A peculiar arrangement of the dermal crests was also observed. In wounds with loss of substance, the complete coating by newly formed basement membrane took longer. There was an early deformation of the holes of hair follicles in the undamaged dermis surrounding the lesion, as well as the appearance of creases that moved toward the center. This process was over within a few days; then the lesion became very small and the holes of the hair follicles reappeared. The results suggest a force of traction bound toward the center of the lesion and acting on the surface, the effects of which on the basement membrane are most evident between the eighth and the 15th days.