Skin surface biopsies

Figure 9.4 shows the appearance of typical parakeratotic cells in SC obtained by skin surface biopsy with tape stripping. As Figure 9.5 shows, no nucleated cells were found in either the controls or HD patients, but they were observed frequently on the lesional skin of AD patients. In some AD patients (16 of 31), they were also found on the nonlesional skin. 

The outermost skin layer, the stratum corneum (SC), consists of corneocytes embedded in lipid layers and represents the main barrier for skin penetration of xenobiotics. Its thickness in healthy adults may vary from 5 to 20 /um, except in the palm and sole where it is much thicker. SC can be removed sequentially by repeated application of appropriate adhesive tapes.1 This technique, commonly known as SC tape stripping, is a relatively noninvasive method to investigate the structure, properties, and functions of SC in vivo2 and is the most frequently used for such purposes. Other techniques to remove SC are skin surface biopsy using cyanoacrylate strips and skin scraping. 

R Marks, ND Ramnarain, B Bhogal, NT Moore. The erythrasma microorganism in situ studies using the skin surface biopsy technique. J Clin Pathol 25[9] 799-803, 1972. 

These authors placed a drop of adhesive glue on a glass slide, which was then placed over the skin and covered with a 200-g cylinder to apply constant pressure for 5 min. The glass shde was thrai removed quickly, and colorimetry was used to assess the resulting biopsy. They performed this procedure twice on each site. It was concluded that the combination of skin surface biopsy and colorimetry has the potmtial to obtain encouraging results, and that the methodology can be extended to the in vivo assessment of more complex formulations. 

Advances of in vivo methods for dermal absorption studies have shown promising results. Microdialysis has bear ranployed successfully for measuring dermal penetration of a wide variety of compounds. This technique has been used extensively in topieal bioavaUabUity and bioequivalenee studies. The noninvasive techniques for percutaneous absorption studies such as tape-stripping, ATR-FTIR, and skin surface biopsies arc also becoming popular because these can be used safely in humans. Regulatory bodies rely on mass balance approaches because all of the topically... 

Marks, R. and Dawber, R.PR., 1971, Skin surface biopsy an improved technique for the examination of the horny layer, Br. J. Dermatol., 84, 117-123. 

Rosado, C. and Rodrigues, L.M., 2003, Solvent effects in permeation assessed in vivo by skin surface biopsy, BMC Dermatol, 3, 1-6. 

Forton F, Seys B (1993) Density of Demodex folliculorum m rosacea a case-control study using standardized skin-surface biopsy. Br J Dermatol 128 650-659... 

The presence of fibres encrusted in the horny layer of the epidermis is clearly shown by the skin surface biopsy technique (Marks and Dawber 1971). The method consists of the following very simple steps ... 

Determination of the presence of particles (and, eventually, of chemicals) in the skin (i.e. using skin-surface biopsy). 

Figure 8.7 Scanning electron micrograph of a skin surface biopsy showing gross disruption in arrangement of squames with prominent gaps (x 1045). Insert shows the microvillous pattern on an individual squame (x2090)...

Skin surface biopsies (SSBs) were taken from the arms (flexor and extensor aspects) of 5 patients with severe dominant ichthyosis using the technique of Marks and Dawber The SSB reveals the ruptured internal surface of the homy layer which partially reflects the internal cohesive forces in the S.C.. ... 

Figure 12.4 Comparison of surfometry tracings from skin surface biopsies (SSB) of a normal individual and a patient with severe dominant ichthyosis...

SEM was performed on both skin surface biopsies obtained using the technique of Marks and Dawber (1971) and on replicas obtained according to the... 

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