Effects of a topically applied preparation of epidermal lipids on the stratum corneum barrier of atopic dogs.

Canine atopic dermatitis (AD) is characterized ultrastructurally by disorganization of the lamellar lipids (LLs) in the stratum corneum (SC), similar to that seen in the human disease. This study, based on the examination of biopsy samples, was designed to investigate the expression of canine epidermal lipids and to evaluate quantitatively, by means of electron microscopy and ruthenium tetroxide post-fixation, the effect of a new topical skin lipid complex (SLC) on the structural deficit in the skin of five dogs with AD. The non-lesional skin of atopic dogs differed from the skin of healthy dogs in that the LLs were reduced in number and highly disorganized.

Melatonin is more effective than taurine and 5-hydroxytryptophan against hyperglycemia-induced kidney-cortex tubules injury.

The antioxidative effects of melatonin (Mel), 5-hydroxytryptophan (5-HTP) and taurine (TAU) on hyperglycemia-induced oxidative stress was investigated in primary cultures of kidney-cortex tubule cells grown in metabolically and hormonally defined medium. In the presence of 30 mm glucose (hyperglycemic conditions), cell viability was decreased by about 35% in comparison with that estimated in the glucose-depleted medium probably as a result of induction of apoptosis, as concluded from: (i) chromatin condensation and DNA fragmentation assays, (ii) a significant enhancement of reactive oxygen species (ROS) production, (iii) 8-hydroxydeoxyguanosine (8-OHdG) generation, (iv) an increased protein peroxidation and (v) a decline of reduced glutathione (GSH) levels leading to a disturbed glutathione redox state. The addition of 100 microm Mel to the hyperglycemic medium resulted in a twofold decrease in both 8-OHdG accumulation and protein peroxidation as well as restoration of the control intracellular ROS levels accompanied by a substantial increase in GSH/oxidized glutathione (GSSG) ratio due to a decline in GSSG content.