Identification of the epidermal barrier: a comprative histological study using different techniques

The present study has been undertaken to re-evaluate the site responsible for the low permeability of skin. Utilization of transmission electron microscopy and electron-dense tracer technique has made it possible to show that all the intercellular spaces of the stratum basale, stratum spinosum, stratum granulosum and, more significantly, the intercellular space between the superficial granular and basal corneal layers of the epidermis are permeated by Lanthanum. In the granular-corneal interface dense deposits of lanthanum and aggregations of excreted contents of lamellar bodies are observed. However, no lanthanum has entered the intercellular spaces of the stratum corneum. The present study suggests that the stratum granulosum and the granular-corneal interface do not function as an effective barrier to the passage of water-soluble intercellular tracers. It is concluded that the intercellular substance in the entire stratum corneum provides or forms "Physiological" tight junctions which impede the movement of water-soluble intercellular tracers and, more significantly, to transepidermal water loss

Complete metopism associated with other cranial abnormalities

Metopism is complete or incomplete persistence of the metopic suture that is normally present between the two frontal bones in the fetus, newborn and early childhood. Identification of the metopic suture and its morphological pattern have been infrequently investigated in some populations using visual inspection of dried skulls, plain x-rays of living and cadaveric heads and routine ultrasonographic examination of fetuses. The aim of the present study is to determine the incidence of persistent complete metopic suture in a collection of dried skull bones and to describe its morphology. We recommend that metopism has to be first ruled out before the diagnosis of frontal bone fracture in case of traumatic injury of the head. Additionally, a diagnosis of an abnormal configuration of the metopic suture in fetuses and newborns might give a clue to other more serious skeletal facial abnormalities