bromochloroacetic-acid and Callosities

Several cosmetic ingredients, especially sunscreens, should be substantive, which means they are to be adsorbed to specific binding sites within the upper skin layers, particularly keratinized structures of the stratum corneum, and thus show resistance to washing off. We investigated the affinity of 10 non-ionic compounds, among these UV-absorbing chemicals, antioxidants, antimicrobial compounds and a repellent to animal keratin and human callus. In each case a linear relationship between the drug amount, which has accumulated in the respective keratin, and the remaining free concentration of the applied solution could be established. Moreover, drug affinities to keratinous substrates are in direct proportion to the octanol/vehicle partition coefficients, pointing to the fact, that drug enrichment in keratinic substrates is clearly governed by lipophilicity, while specific adsorption, i.e. genuine substantivity, does not seem to occur. After application of a saturated solution non-ionic compounds with a pronounced keratin/vehicle partition coefficient will build up the highest concentration within the stratum corneum. If these compounds show, at the same time, a high solubility in the vehicle, they will penetrate the skin most easily. The used callous tissue seems to be a suitable substrate to simulate and quantify solute uptake into human skin.

Topics: Animals; Callosities; Calorimetry, Differential Scanning; Cattle; Chromatography, High Pressure Liquid; Cosmetics; Humans; Keratins; Lipids; Sunscreening Agents

Topics: Callosities; Humans; Keratins; Microscopy, Electron; Skin; Skin Abnormalities

Keratin was extracted from normal human horny cells of the leg, calluses of the sole, and psoriatic scales. After dissociation in sodium dodecyl sulfate the polypeptides were separated by Laemmli's gel electrophoresis method and their molecular weights and relative amounts determined. Normal horny cells contained 3 polypeptide chains of Mr 67K, 59K, and 57K, while those of callus contained 9 polypeptides of Mr 67K, 66K, 63K, 62K, 58K, 54K, 52K, 48K, and 45K. In both cases all keratin polypeptides participated in filament reassembly in vitro and were recovered from the filaments. In psoriatic scale keratin, 7 prominent polypeptides were detected having Mr 67K, 59K, 57K, 50K, 48K, 42K, and 40K. The 67K polypeptide could not be recovered from reassembled filaments. Ultrastructural studies revealed that these filaments are imperfect and readily aggregate into thick fibrils. These observations indicate that there are significant differences in composition of keratin of normal horny cells, calluses, and psoriatic scales.

Topics: Callosities; Electrophoresis, Polyacrylamide Gel; Epithelium; Humans; Keratins; Peptides; Psoriasis

Polyacrylamide gel electrophoretic investigations were carried out on solubilized proteins from psoriatic and normal stratum corneum obtained by adhesive tape stripping. The proteins in the scales adhering to the tape were solubilized by incubating the tape in 1% sodium dodecyl sulphate (SDS) solution. The electrophoretic behaviour of these solubilized proteins on SDS-polyacrylamide gel was compared with the alpha-fibrous proteins (keratin) of callus. The proteins isolated from callus of normal human heel showed six main bands which were similar to those of the keratin isolated by the 8 M urea-mercaptoethanol method. The lesional skin of forty-five psoriatic patients consistently showed nine main bands on polyacrylamide gels, but only two main bands were observed in the non-lesional, non-heel skin. Six of these nine bands had mobilities and relative intensities almost identical with those of alpha-keratin extracted by the mercaptoethanol method, but the other three bands had greater mobilities on the gels. These results suggest that this technique may have considerable potential for studying changes in alpha-keratin in patients with psoriasis and other disorders of keratinization.

Topics: Callosities; Electrophoresis, Polyacrylamide Gel; Humans; Keratins; Methods; Proteins; Psoriasis; Skin

The structure of single filaments of horny cells of normal and psoriatic epidermis was studied in the electron microscopy in situ and in filaments reconstituted from urea extracts by dialysis, against low ionic strength buffer. It was found that both in situ and reconstituted filaments consist of 20 A protofibrils. In filaments of normal horny cells the protofibrils seem to form a rope-like structure while in those of psoriatic horny cells protofibrils appear randomly arranged. The filaments reconstituted from extracts of psoriatic scales range in width from 90 to 500 A, indicating a defect in lateral assembly of protofibrils. Numerous small particles are detectable at high magnification in extracts of both normal and psoriatic horny cells, which are about 20 A wide and 200 A long. These particles are consisted to be the basic structural units from which the protofibrils are formed, by end-to-end junctions.

Topics: Callosities; Cytoskeleton; Epidermis; Humans; Keratins; Microscopy, Electron; Psoriasis

The chemistry and structure of the epidermal alpha-keratin extracted from the skin of patients with a variety of disorders of keratinization have been investigated using biochemical, biophysical, and electron microscopic techniques developed for the characterization of normal mammalian epidermal keratin. Generally, the alpha-keratin polypeptides of the diseased epidermis differed from those of uninvolved epidermis or of normal volunteers in having varying numbers of polypeptide components of lower molecular weights, numerous free amino acids, higher contents of alpha-helix, and only limited facility for polymerization in vitro into native-type epidermal keratin filaments. As the alpha-helix-enriched fragments, which represent up to two-thirds of the polypeptide chains, isolated after limited tryptic digestion of the keratin filaments of normal, uninvolved, and involved epidermis, were physicochemically identical, it seems that the end-terminal non-alpha-helical regions of the polypeptides of diseased epidermis are abnormal. These differences may be a result of degradation or of altered protein synthesis.

Topics: Amino Acid Sequence; Callosities; Cytoskeleton; Epidermis; Humans; Keratins; Microscopy, Electron; Molecular Weight; Protein Conformation; Psoriasis; Skin Diseases

Topics: Amino Acids; Autoanalysis; Cadaver; Callosities; Chemical Precipitation; Chromatography, Gel; Dextrans; Electrophoresis, Polyacrylamide Gel; Humans; Hydrogen-Ion Concentration; Ichthyosis; Keratins; Protein Denaturation; Psoriasis; Skin; Tissue Extracts

Topics: Adult; Callosities; Female; Hair; Histocytochemistry; Humans; Infant; Intercellular Junctions; Keratins; Male; Methods; Microscopy, Electron; Nails; Osmium; Psoriasis; Skin; Staining and Labeling; Thioglycolates

Topics: Adult; Callosities; Extracellular Space; Humans; Intercellular Junctions; Keratins; Male; Microscopy, Electron; Microscopy, Electron, Scanning; Thioglycolates

Topics: Biochemical Phenomena; Biochemistry; Callosities; DNA; Electrophoresis; Hair; Histocytochemistry; Humans; Keratins; Nails; Nitrogen; Proteins; Psoriasis; Skin; Sulfhydryl Compounds

Topics: Callosities; Epidermis; Humans; Keratins; Phosphates; Psoriasis; Skin; Water

Topics: Acetates; Callosities; Hair; Keratins; Keratins, Type II; Nails; Psoriasis; Sulfhydryl Compounds; Thioglycolates

Topics: Callosities; Epithelium; Humans; Keratins; Skin; Skin Physiological Phenomena