Biomedical subjects

W Sterry

Publications and source records attributed to W Sterry.

330 records · Page 19Linked to original sources

PubMedDate not supplied

UV/VIS absorbance allows rapid, accurate, and reproducible mass determination of corneocytes removed by tape stripping.

The accurate determination of the mass of the horny layer removed by tape stripping is a decisive prerequisite for the application of this technique in penetration studies. A novel method using optical spectroscopy to determine the amount of stratum corneum (SC) is presented. We could show that the absorbance measured in the visible spectral range accurately reflects the mass of the SC fixed on individual tapes. Furthermore, absorbance measurement allows determination of the absolute mass of corneocyte aggregates on the removed tape strips. Topically applied substances do not disturb the spectroscopic measurements in contrast to the conventionally employed weight determination. Identical results were obtained when performing spectroscopic horny layer quantification independently in two separate institutions. Taken together, this new method is rapid, sensitive, reproducible, and accurate. We anticipate a wide application in penetration studies as well as in dermatopharmacokinetics.

Adult↗

PubMedDate not supplied

Evaluation of the pseudo-absorption method to quantify human stratum corneum removed by tape stripping using protein absorption.

Tape stripping is a well-known method to study the barrier function of the stratum corneum (SC) and penetration processes of topically applied substances into the horny layer. The quantification of the removed corneocytes for each tape strip is the prerequisite for these studies. The pseudo-absorption of the corneocytes was proposed as a measure for the quantification of the removed corneocyte aggregates. In this study, the pseudo-absorption of the corneocytes in the visible range (430 nm) is compared with the protein absorption in the UV range (278 nm) and an absorption at 652 nm obtained after staining of the SC proteins with Trypan blue. Both the protein absorption and the absorption measured after staining correlate well with the pseudo-absorption measured at 430 nm (R(2) = 0.92 +/- 0.04 and R(2) = 0.95 +/- 0.04, respectively).

Adult↗

PubMedDate not supplied

Lateral spreading of topically applied UV filter substances investigated by tape stripping.

The lateral spreading of topically applied substances is a competitive process to the penetration into the stratum corneum (SC). The penetration of topically applied UV filter substances into the human SC and the lateral spreading were investigated in vivo. Tape stripping in combination with spectroscopic measurements was used to study both processes of two UV filter substances. The concentration of both UV filters was determined inside and outside the application area by varying the application and tape stripping protocol. A spreading of the topically applied substances from the treated to the untreated areas was observed, which caused a concentration gradient. This lateral spreading depends on the time between application and tape stripping and the size of the treated skin area. Significant amounts of topically applied substances were found adjoining the application area, due to the lateral spreading which takes place on the skin surface. In general, the lateral spreading must be considered to be a competitive process when studying penetration processes of topically applied substances. It has to be considered during drug treatment of small limited skin areas and for the interpretation of recovery rates obtained in penetration studies.

Administration, Cutaneous↗

PubMedDate not supplied

Reservoir function of the stratum corneum: development of an in vivo method to quantitatively determine the stratum corneum reservoir for topically applied substances.

Investigations on the stratum corneum (SC) reservoir for topically applied substances are of importance in dermatologic science in order to assess the pharmacokinetics of these substances. In the present study, an in vivo method was developed to determine the SC reservoir quantitatively and to investigate the temporal behavior of this reservoir. Therefore, increasing amounts of an oil-in-water emulsion (o/w emulsion) containing 4% of a chemical UV filter were topically applied onto the flexor forearms of 5 healthy volunteers. The saturation of the SC reservoir was determined utilizing the tape stripping technique 1 and 6 h after application. The capacity of the SC reservoir for the o/w emulsion was found to be approximately 2.7 mg/cm(2). Furthermore, a correlation of the capacity of the SC with transepidermal water loss was observed. Extending the time between the topical application and SC removal did not affect the distribution or the recovery rate of the UV filter in the SC. The results indicate that the reservoir of the SC is limited. This is reflected by the saturation level, which depends on the individual volunteer and, presumably, the topically applied substances and formulations used. The results show that the method developed is suited to quantitatively determine in vivo the SC reservoir for topically applied substances.

Administration, Topical↗

PubMedDate not supplied

Chronic indurated ulceration of the leg, epithelioid sarcoma with lymph node metastasis.

Epithelioid sarcoma is a seldom seen tumor characterized by an innocuous presentation of a non tender nodule or cluster of nodules located on a distal extremity with a high propensity for nodal spread as well as relentless local progression. We describe a patient with the neoplasm masquerading as chronic leg ulcers of unknown origin with an unusual immunohistochemical profile. The difficulty of timely clinical and histological diagnosis is a key problem encountered. Better awareness may result in earlier diagnosis and improved prognosis.

Aged↗

PubMedDate not supplied

[Increased expression of adhesion molecules in oral lichen planus].

Adhesion of cells to other cells and to the matrix is the prerequisite for a multitude of cell interactions such as the emigration of circulating leukocytes to sites of inflammation, antigen-presentation, cell-mediated cytotoxicity, cell anchorage and differentiation. In the past few years, a large family of adhesion molecules has been defined which are receptors for these adhesion events. Using immunohistochemical techniques we analyzed the distribution pattern of adhesion molecules in the buccal mucosa of 12 patients with oral lichen planus reticularis and compared it with 12 specimens of normal oral mucosa. In lichen planus, a neo-expression of the antigens VLA-1, 3, 5 and 6, which are receptors for collagen, fibronectin and laminin, could be detected on T cells and macrophages infiltrating the basement membrane zone. ICAM-1, the specific ligand of LFA-1, normally only expressed by endothelial cells, showed a focal expression on basal keratinocytes at sites of intramucosal T cells. The abundance of adhesion molecules on leukocytes and keratinocytes in oral lichen planus is indicative of a special state of activation. It enables the leukocytes to penetrate the tissue, especially the basement membrane zone, to persist in this environment and to exercise their effector functions.

Antigens, CD↗