many properties of chemicals depend on their streochemistry. among these, the effects of streoisomerism on percutaneous absorption of drugs, which is subject of the present investigation, is not well studied yet. in this study, tretinoin (tt) and isotretinoin (itt) (geometric isomers) were chosen and their permeations (alone or in the presence of each other) through enhancer-treated excised rat...

Animal models are important tools to predict human in vivo percutaneous absorption/penetration. Monkey, pig, rat, rabbit, guinea pig, hairless rodents, such as hairless rat, hairless mouse, hairless guinea pig and hairless dog, are among the most used animals for this purpose. Each animal model has its own advantages and weakness or limitation. To better correlate animal data with human skin ab...

1. The plasma of guinea pigs treated by injections of rat sarcoma exhibits a toxic action in tissue culture preparations on the cells of both rat sarcoma and rat embryo skin. Similarly, the plasma of guinea pigs immunized by injections of rat embryo skin is toxic for cells of both types. 2. Injection of rat blood immunizes against both sarcoma and embryo skin, although not so strongly as inject...

The existence of the glycolytic sequence of enzymes in rat skiu is suggested by the data of a number of investigators. For example, Barron et al. (1) found that the endogenous, anaerobic evolution of CO, in slices of rat skiu was inhibited by iodoacetate, fluoride, and glyceraldehyde. Dixon and Needham (2) reported that their investigation into the mechanism of vesicant actiou indicated that th...

Collagen is an ubiquitous structural protein, which constitutes about 25-30% by weight of all proteins in the mammalian body. It functions as an important supporting element in vertebrate tissues. Using the method of cleaving the protein chains at the methionyl residues with cyanogen bromide (CNBr), many species of collagen from different sources have been isolated and characterized, e.g. rat s...

Macromolecular heparin from rat skin shows poor lipoprotein lipase-releasing activity in vivo and is a potent inhibitor of rat-heart lipoprotein lipase in vitro. Rat-skin heparin is depolymerized by incubation with the 100,000 x g supernatant from a sonicated homogenate of rat small intestine. The depolymerized products, fractionated by gel filtration, range from inhibitors to activators of lip...

All LMW respiratory allergens known to date can also induce skin allergy in test animals. The question here was if in turn skin allergens can induce allergy in the respiratory tract. Respiratory allergy was tested in Th2-prone Brown Norway (BN) rats by dermal sensitization with the contact allergen dinitrochlorobenzene (DNCB; 1%, day 0; 0.5%, day 7) and a head/nose-only inhalation challenge of ...