bromochloroacetic-acid and n-hexadecane

A method for analyzing free nucleotides in the epidermis of the guinea pig is presented. Free nucleotides were extracted by using a methylalethanol mixture, and the analysis was carried out by high-pressure liquid chromatography on a column of Lichrosorb-NH2 with a single buffer of potassium phosphate. The concentration of total free nucleotides in the epidermis is about 4 times greater than that in the liver, kidney, spleen, or intestinal epithelium.l The free nucleotide level is markedly elevated in the hyperkeratotic epidermis induced by n-hexadecane. The alternation of free nucleotides in hyperkeratotic epidermis is discussed in relation to nucleic acid content, DNase, disc-electrophoretic properties of DNase, and salvage pathway enzymatic activity. Significant increases in the enzyme activity of the salvage pathway and in neutral DNase were observed in the hyperkeratotic stage. However, the DNA content and acid DNase activity were decreased. It is suggested that the pool size of free nucleotides in the epidermis is affected by the salvage enzyme system.

Topics: Alkanes; Animals; Chromatography, High Pressure Liquid; Deoxyribonucleases; Epidermal Cells; Epidermis; Guinea Pigs; Keratins; Nucleic Acids; Nucleotides; Skin

Evidence is provided for a possible dermal influence on the epidermis. Topical vitamin A stimulates a number of dermal cells with different enzyme reactions, and these invade the epidermis at about the time a granular layer is induced in mouse tail scale epidermis. N-hexadecane also induced a granular layer formation in the tail scale epidermis but the application of this agent only results in the invasion of the epidermis by non-specific esterase cells. These non-specific esterase cells are present in the follicular zone where a granular layer is usually present. It appears that dendritic cells may be responsible for the formation of a granular layer and that these cells in some way influence the keratinocytes to discharge their lyosomal enzymes and thus form a granular layer. It appears unlikely that the dendritic cells actually contribute their own acid hydrolases to the cell cytolysis necessary for the production of granular layer.

Topics: Acid Phosphatase; Adenosine Triphosphatases; Administration, Topical; Alkanes; Animals; Coal Tar; Epidermal Cells; Epidermis; Esterases; Granulation Tissue; Keratins; Male; Mice; Monophenol Monooxygenase; Skin; Vitamin A

The C-14 content of epidermis, dermis, subdermal muscle and certain other tissues was determined 48 hours following topical application of hexadecane-1-C-14 to the skin of guinea pigs. The effect of simultaneous application of U.S.P. heavy mineral oil, n-docosane, and heptane as well as hexadecane pre-treatment on the extent of penetration of hexadecane-1-C-14 was also measured. Large amounts of C-14 were found in the epidermis whereas relatively little accumulated in the dermis and underlying tissues. Each of the carrier vehicles reduced the amount of C-14 in the epidermis; whereas, docosane and mineral oil, but not heptane, reduced the amount of C-14 in the dermis and subdermal muscle. This correlated with the ability of heavy mineral oil and docosane, but not heptane, to decrease the dermatoxic effects of hexadecane. Pre-treatment of the skin with hexadecane 48 hours prior to application of hexadecane-1-C-14, if anything, increased the amount of the C-14 in the epidermis; however, pre-treatment with mineral oil:hexadecane reduced the amount of epidermal and dermal C-14 from a subsequent application of mineral oil:hexadecane-1-C-14. The results support the proposal that heavy mineral oil and alkanes with a chain length of over 20 carbon atoms reduce the dermatoxic effect of hexadecane by interfering with its penetration to the site of action. This site would appear to be either the deeper layers of epidermis or possibly the dermis. The increased uptake of hexadecane-C-14 by the epidermis following pretreatment with hexadecane provides a possible explanation for the more severe response seen with multiple hexadecane applications as opposed to a single application of the same amount of material.

Topics: Administration, Cutaneous; Alkanes; Animals; Carbon Radioisotopes; Guinea Pigs; Heptanes; Keratins; Male; Mineral Oil; Pharmaceutical Vehicles; Skin; Skin Absorption; Time Factors

Topics: Alkanes; Body Weight; Guinea Pigs; Hydrocarbons; Hyperplasia; Keratins; Keratosis; Keratosis, Actinic; Metabolism; Pharmacology; Research; Skin; Toxicology; Water