Epitheliogenesis imperfecta in a crossbred Holstein calf, southwestern Iran

Epitheliogenesis imperfect (EI) is a rare autosomal recessive skin defect that is clinically identified with absence of cutaneous epithelium of the limbs, muzzle and nostrils as well as oral mucous membranes. This congenital newborn desease is reported mainly in domestic animals. The present study described EI in a 13 day-old, female crossbred Holstein calf. Gross examination showed epithelium agenesis of two front and hind limbs skin around the carpal and tarsal joints, and also extensive areas of the metacarpal and metatarsal regions. The calf died 5 days after antibiotic therapy and use of topical cream.

NGF mRNA expression in developing cutaneous epithelium related to innervation density

To determine if the initial level of NGF mRNA in developing cutaneous epithelium is correlated with its final innervation density, we measured the concentration of NGF mRNA in the epithelia of the maxillary, mandibular and ophthalmic territories of trigeminal ganglion in the embryonic mouse. At the onset of neuronal death in the ganglion there were marked differences in the concentration of NGF mRNA in these epithelia: the level was highest in the epithelium of the densely innervated maxillary territory, it was lower in the epithelium of the moderately innervated mandibular territory and was lowest in the epithelium of the sparsely innervated ophthalmic territory. These regional differences in the level of NGF mRNA during the early stages of target field innervation suggest that the level of NGF production in target field cells, rather than regional differences in the access of innervating neurons to NGF, governs the number of neurons that survive. Because the same percentage cell death occurs in each of the subsets of trigeminal neurons that innervate the maxillary, mandibular and ophthalmic territories, regional differences in NGF synthesis are not responsible for establishing differences in innervation density, rather they maintain differences that arise earlier in development.

Calcium exchange in isolated cutaneous epithelium of toad Bufo marinus

The Ca content of isolated cutaneous epithelium of toads (Bufo marinus) was 5 mmol/kg wet wt (compared with approximately 300 mmol/kg wet wt for intact skin), of which approximately 1.7 mM is not readily exchangeable with external 45Ca. After incubation in a solution containing 45Ca, loss of the accumulated isotope in an isotope-free medium is almost complete in 2 h. This efflux or washout is reduced by the presence of external Ca- and Na-free media and by La. Loss of Ca from the epithelium may thus reflect the presence of several mechanisms including a Ca-Ca exchange and a Ca-Na exchange. The effect of La (2 mM) was greater than that of a Na- and Ca-free medium, possibly reflecting the presence of an uncoupled Ca extrusion or extrusion by a Ca-ATPase (pump) mechanism. Drugs (ouabain and amiloride) that, respectively, increase or decrease levels of internal Na had no significant effects on efflux or accumulation of Ca. Vasopressin was also without such effects on Ca.