Postnatal development of intestinal villi in the rat. Determination of villus size gradient.

The existence of the so called "Villus Size Gradient" (VSG) which defines the proportional decrease in height of intestinal villi from duodenum to ileum is well documented in adult animals and man. The aim of this study is to define whether the VSG is present since birth or, if not, when and why it appears. We have measured the height of intestinal villi in 25 rats: 5 at 1 day from birth, 5 at 5 days, 5 at 8 days, 5 at 15 days and 5 at 30 days. We have prepared histological slides of a duodenal, jejunal and ileal tract of each animal and measured the height of villi on microphotographs. At day 1 we observed a higher size of duodenal villi statistically significant with respect to jejunum and ileum, while at day 5 no differences were observed between the various intestinal tracts. The VSG become evident 8 days after birth progressively increasing to day 30. The predominance of duodenum present at birth is therefore probably due to the fetal developmental growth which is known to be more precocious in duodenum than in more distal tracts. Five days after birth the intestinal villi are equally developed, while in later ages the VSG appears. So we can conclude that the VSG is a consequence of luminal and humoral factors and not a predetermined event.

Sensory endings in skin grafts and scars after extensive burns.

Fifteen patients who underwent a split thickness skin graft operation for full thickness burns and six patients with postburn scars were biopsied after a standard aesthesiological examination completed with Weber and Dellon tests. A semiquantitative evaluation was performed on immunohistochemically stained sections to determine the presence or absence of PGP 9.5 immunoreactive intraepithelial fibres, complex sensory receptors, nerve fibres in the dermal papillae, vessel-innervating fibres, gland-innervating fibres, and nerve trunks in the deep dermis. The reinnervation pattern was similar in grafts and scars. With regard to sensory receptors, free nerve endings and Merkel-neurite complexes were observed. Statistical analysis suggested a significant correlation between sensibility and the amount of regenerated nerve structures (particularly in the epidermis and dermal papillae).

Morphology of corpuscular receptors in hairy and nonhairy human skin as visualized by an antiserum to protein gene product 9.5 compared to anti-neuron-specific enolase and anti-S-100 protein.

The present study elucidates the morphology of encapsulated receptors in human skin by means of immunohistochemistry for the recently characterized neurospecific marker protein gene product 9.5, in comparison with neuronal specific enolase and S-100 protein. Only two types of corpuscles are identified, Meissner's corpuscles and simple coiled corpuscles. Moreover, this investigation reveals that though regional specialization may exist with regard to the encapsulated receptor density, the comparison of hairy and nonhairy skin does not reveal important differences.

An immunohistochemical study on cutaneous sensory receptors after chronic median nerve compression in man.

Carpal tunnel syndrome represents the most frequent chronic compressive neuropathy in man and hence may be investigated as a spontaneous model of peripheral nerve damage and repair. In the present report the fate of nerve fibers in the digital skin after long-lasting median nerve compression has been investigated immunohistochemically in comparison to normal digital skin, with special consideration to sensory endings and encapsulated receptors. The presence has been documented of the neurospecific marker PGP 9.5, the glia-associated protein S-100, and the neuropeptides CGRP and CPON which are mainly associated with the sensory and sympathetic nerve fibers respectively. The morphology and distribution of nerve fibers and corpuscles appeared comparable to that of normal digital skin; a reduction in the density of sensory receptors has, however, been observed, although not to the degree that was expected to explain the clinical deficits. It has been also demonstrated that at least part of the CGRP-containing sensory and CPON-containing sympathetic axons may survive unaltered even in patients with a long clinical history of profound sensorial impairment. An apparent discrepancy between the maintenance of nerve fibers and the sensory disturbances and the frequent observation of prompt postoperative recovery even after years of compression results from this investigation. The correlation of immunohistochemical observations and functional scores may not be considered conclusive. It must, however, be discussed if the sensorial impairment in this syndrome might have, at least in some cases, not only an anatomical but also an electrophysiological basis.