Study skins

Toxicological studies Skin irritation rabbit test... 

N. Sekkat, R. H. Guy, Biological Models to Study Skin Permeation , in Pharmacokinetic Optimization in Drug Research Biological, Physicochemical and Computational Strategies , Eds. B. Testa, H. van de Waterbeemd, G. Folkers, R. Guy, Verlag Helvetica Chimica Acta, Zurich, 2001, p. 155- 172. 

In mice skin-painting studies, skin tumors were produced by steam-refined petroleum bitumens, an air-refined bitumen in toluene, two cracking residue bimmens, and a pooled mixmre of steam- and air-blown petroleum bitumens. In contrast, standard roofing petroleum asphalts produced no tumors. 

Diglycidyl ether is extremely damaging to skin, producing ecchymoses and necrosis. In one long-term study, skin painting three times per week for 1 year caused hyperkeratosis, epithelial hyperplasia, and skin papillomas. ... 

Marzulll, F.N., and Maibach, H.l. The use of graded concentrations In studying skin sensitizers Experimental contact sensitization in man. Food Cosmet. Toxicol. 12 219-227, 1974. 

Kuzmina, N., Hagstromer, L., and Emtestam, L., Urea and sodium chloride in moisturisers for skin of the elderly—a comparative, double-blind, randomised study, Skin Pharmacol. Appl. Skin Physiol., 15 (3), 166, 2002. 

The friction coefficient varies with anatomical site Cua et al.8,22 found that friction coefficients varied from 0.12 on the abdomen to 0.34 on the forehead. Eisner etal.11 measured the vulvar friction coefficient at 0.66, whereas the forearm friction coefficient was 0.48. Sivamani et al.24 found that the proximal volar forearm had a higher friction coefficient than the distal volar forearm. Manuskiatti et al.23 studied skin roughness and found significant differences in skin roughness at various anatomical sites. Differences in environmental influences (i.e., sun exposure) and hydration may account for this. Eisner et al.11 showed that the more-hydrated vulvar skin had a 35% higher friction coefficient than the forearm, and this is in agreement with hydration studies that contend that skin has an increased friction coefficient under increased hydration. 

Vertebrate animals may be preserved dry or in fluid. Traditional systematic species collections may include study skins, skeletons, and fluid-preserved animals or body parts. Study skins are, as the name implies, the skin of the animal with hair and feathers intact. In small animals, the bones are often left in place since it would be too difficult and damaging to remove them. In study skins, the eyes and mouth are usually filled with cotton, and the body is stuffed gently with either cotton or acid-free tissue in order to keep the skin extended to its original size and shape. Large animals, such as whales or elephants, require a great deal of preparation and storage space. Some researchers may keep only those parts that are relevant to their collections, like the skull or extremities. Soft tissue or stomach contents may be frozen or preserved in alcohol. 

Fur rugs and wall hangings are created in much the same way as study skins and taxidermy mounts, except that the bones are completely removed and the skin is trimmed into the desired size and shape. An exception to this is the trophy mg, in which the head and sometimes the feet are left intact. 

Vertebrates Mammals Study skins, pelts, mounted specimens (taxidermy), whole or partial skeletons, teeth, wet-preserved animals, parts, or stomach contents, eggs, nests Ivory, ruminant horn, rhino horn, antler, bone, claws, skin (leather, vellum), hair (bristles, quills, fur) hooves... 

Vertebrates Reptiles and amphibians Study skins, mounted specimens (taxidermy), whole or partial skeletons, wet-preserved animals or parts Tortoise shell, teeth, skin... 

Leveque, J. L. and De Rigal, J. Impedance methods for studying skin moisturiza-tion. J. Soc. Cosmet. Chem. 34 419, 1983. 

See also Aniline Cosmetics and Personal Care Products Safety Testing, Clinical Studies Skin Toluidine. 

Phorbol esters were first detected in oil prepared from seeds of Croton tiglium, and are the most widely studied skin tumor promoters however, many other chemical compounds have been shown to possess skin tumor-promoting properties, for example, phenobarbitol, DDT, and the peroxisomal prolifera-tors. Within a few hours after application of a single effective dose of phorbol 12-myristate 13-acetate (also known as TPA and 12-O-tetradecanoyTphor-boTl3-acetate, CAS 16561-29-8) to mouse skin, localized edema and erythema characteristic of inflammation and irritation are evident, and within 24 h there is leukocytic infiltration of the dermis. Within 1 or 2 days after a single promoter treatment, stimulation of mitotic activity in the basal cell layer of the epidermis is evident and continues for several days. This results in an increased number of... 

Human skin equivalents have been developed by several laboratories. One equivalent, Testskin, consists of human keratinocytes seeded onto a collagen base or collagen-glycosaminoglycan matrix containing human fibroblasts. In many respects, the epidermis which develops resembles epidermis in vivo. The tissue culture system survives for several weeks and may be useful in studying skin penetration. Testskin is a commercially produced skin equivalent system marketed by Organogenesis, Inc. (Cambridge, MA) ... 

Buchanan, T. M., Faber, L. C., and Feldman, R. A., Brucellosis in the United States, 1960-1972. An abattoir-associated disease. Medicine 53, 403-413 (1974). Butler, T, A clinical study of the bubonic plague. Observations of the 1970 Vietnam epidemic with emphasis on coagulation studies, skin histology and electrocardiograms. Am. J. Med. 53, 268-276 (1972). 

Marzulli, F.N., Brown, D.W.C., and Maibach, H.I. (1969). Techniques for studying skin penetration. Toxicology and Applied Pharmacology, Supplement 3 76-83. 

Kommuru, T.R. Khan, M.A. Reddy, I.K. Racemate and enantiomers of ketoprofen phase diagram, thermodynamic studies, skin permeability, and use of chiral permeation enhancers. J. Pharm. Sci. 1998, 87, 833-840. 

Marzulli FN, Maibach HI (1974) The use of graded concentrations in studying skin sensitizers experimental contact sensitization in man. Fd Cosmet Toxicol 12 219-227 Marzulli FN, Maibach HI (1977 a) Dermatotoxicology and pharmacology. John Wiley Sons, New York Chichester... 

Therkildsen, R, Hasdersdal, M., Lock-Andersen, J., Olivarisu, F. dF., Poulsen, T., Wulf, H.C., 1998. Epidermal thickness measured by light microscopy a methodological study. Skin Res. Technol. 4, 174—179. 

Use of an exposure chamber designed for experiments with controlled exposure to airborne particles, mainly skin and respiratory allergens and irritants. The aims are to study skin effects and to develop methods for the measurement of the deposition of particles on the skin (Liden et al. 1998). 

On occasion, such a survey may indicate the need for a more formal epidemiological study. Skin complaints may, for example, be widespread but unusually hard to explain. Such investigations should never be undertaken by clinicians without previous epidemiological and statistical consultation. Coenraads and Nater (1987) have published a useful introduction to the problems that may arise, including true prevalence estimation, bias, confounding variables and sample size. Questions of disease definition and inter-observer variability are not necessarily familiar to clinicians, who may therefore need to seek epidemiological advice at the earliest opportunity. Questionnaires are frequently designed that ask for far more detail than can possibly be usefully analysed statistically, and they should always be piloted first in order to achieve validity. 

The efficacy of some modifications in correcting the assay were studied. Skin biopsies were removed and cultured by standard methods (3). Cell extracts were prepared by freezigg and thawing of concentrated cell suspensions (>6x10 /ml) in the presence of 1 mM PRPP. HGPRT and APRT were determined in the dialyzed supernatants of the cell extracts by a radiochemical method in which the labelled purine bases are converted to their respective nucleotides by reacting with PRPP,... 

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