A. Di Nardo

Echographic Evaluation with Image Analysis of Normal Skin: Variations according to Age and Sex

In order to identify and characterize the sonographic variations between different age groups, 48 subjects, 24 aged 27-30, and 24 over 60, were studied with a 20-MHz B scanner on six skin sites. Images were evaluated by the instruments standard programme and by a new image analysis software package enabling the characterization of steady structures or transitory functional aspects of skin reactions, by highlighting areas in which the echo amplitudes are included within selected values, and by calculating their extension. Three bands were selected as intervals of interest, respectively, highlighting hyporeflecting parts of the dermis, tissue reflecting with intermediate amplitude values and hyperreflecting epidermis and dermis. This method was employed to assess skin thickness, demonstrating its decrease in elderly skin, to characterize and quantify the hypoechogenic subepidermal band appearing in the elderly at volar and dorsal forearm skin, and to evaluate echogenicity of the upper and lower dermis. Our data show that there is a great regional variation in the behaviour of ultrasound reflection of elderly skin in respect to the skin of young subjects. However, a general trend can be identified, consisting in a shift from low-intensity ultrasound echoes, characteristic in the dermis of young subjects, to intermediate or high reflection amplitudes, which are more frequent in elderly skin. Thus, the echographic method provides two parameters for the evaluation of skin aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Ceramide 2 (N‐acetyl sphingosine) is associated with reduction in Bcl‐2 protein levels by Western blotting and with apoptosis in cultured human keratinocytes

Background  Ceramides produced by sphingomyelin hydrolysis activate a cycle that is followed by three different major cellular responses: downregulation of cell proliferation, induction of cell differentiation and apoptosis. In the skin, the generation of intracellular ceramide may also provide a link between an extracellular signal and the induction of the apoptosis programme for the elimination of damaged cells. Objectives We investigated the effect of ceramides capable of entering cells on cultured keratinocytes. Methods Human keratinocytes from neonatal skin were cultured in serum‐free medium with or without increasing concentrations of ceramide 2 (CER‐2; N‐acetyl sphingosine) (5, 10, 20 and 40 µmol L−1). Proliferative effects were studied either by cell counts or by 3H‐thymidine incorporation and flow cytometric analysis. Apoptosis was studied by TUNEL staining and Western blot analysis of Bcl‐2 protein. Results Cell counts and DNA synthesis were reduced in a dose‐dependent manner following CER‐2 treatment. TUNEL staining showed CER‐2‐induced apoptosis at 48, 72 and 96 h. Western blot analysis showed that CER‐2 induces downregulation of Bcl‐2 at 24–96 h. Conclusions These results demonstrate that CER‐2 inhibits cell proliferation and induces apoptosis, possibly via a Bcl‐2‐dependent mechanism.

Echographic evaluation with image analysis of histamine-induced wheals.

10 healthy, non-atopic women, aged 20-30, underwent histamine prick tests, performed in duplicate on the volar surface of the forearm with progressively increasing histamine concentration, from elbow to wrist on the left arm and from wrist to elbow on the right. Histamine wheal assessments were performed with the following methods at 5, 10, 15 and 20 min from challenge: planimetry for wheal area determination, A-scanning for skin thickness evaluation and echographic image analysis for assessing skin edema corresponding to the hypoechogenic area in the dermis. Wheal extension, skin thickness and edema of the dermis increase in time according to the histamine concentration. However, in response to the same concentration, regional variations consisting in greater wheal extension and dermis hypoechogenic areas were observed on proximal than on distal sites. Conversely, statistically significant differences were found between tests carried out on the right arm compared to those on the left regarding skin thickness. These variations have to be considered when interpreting data derived from pharmacological studies on the inhibition of histamine-induced reactions.