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A quantitative study of dermal collagen as a function of age was carried out by computerized digital image analysis. Fast Green-Syrius Red stained sections were obtained of skin biopsies taken from the upper inner arm of 33 healthy women and 38 healthy men. The Leitz texture Analysis System (Leitz-TAS) and mathematical morphology (Serra, 1982) were used for the evaluation of the data. Collagen was studied in the superficial dermis and also in the reticular dermis using the same program. There were significant correlations, firstly between the percentage of collagen measured by the morphometric method and the concentration of collagen analysed biochemically (microg/mm(2) of tissue section) (r = 0.79, p < 0.001) and secondly between the decreased concentration of collagen and age (r = 0.58, p < 0.05). The morphometrical measurements have shown that the relative percentage of collagen bundles (surface of collagen fibers as a function of the dermal area analyzed) was 93.35% in the superficial dermis and 89.2% in the reticular dermis. Although this value is higher than the chemically determined ratio of collagen to other proteins (over 70%), this may be due to the relatively uniform distribution pattern of (type I and III) collagen through the dermis covering most other components of the skin. As the collagen fiber density per unit dermal surface did not change with age, the decrease in collagen content of the skin may be ascribed to the loss of about 6% of dermal mass per decade (Branchet, 1990), although large individual variations exist. The histogram of the diameter distribution of collagen fiber bundles of the reticular dermis showed thinner diameters in persons between 20 and 40 years of age than in older persons. The histogram of the distribution of interfiber spaces did not show any variation with age in the superficial dermis, while in the reticular dermis there was a predominance of smaller interspaces in persons older than 50 years.

A quantitative study of dermal elastic fibers was carried out by computerized digital image analysis. Sections of skin biopsies taken from the upper inner arm of 33 healthy women and 38 healthy men were stained by a selective procedure for elastic fibers. The Leitz texture analysis system (Leitz-Tas) and mathematical morphology were used for the evaluation of the data. Distinct programs were used for the vertical superficial elastic fibers and for the mature elastic fibers of the reticular dermis. For elastic fibers of the superficial dermis there was no significant variation with age or sex for total area occupied by the fibers or for the total number of fibers per unit skin area or total fiber length. The distribution of the relative fiber number as a function of their length showed that about 80% of the fibers had a length of 0–20 μm, with no detectable age- or sex-dependent variation. The distribution of fiber number frequency as a function of fiber diameter did not show any significant variation with sex or age, either. The relative area of mature elastic fibers increased significantly with age after the sixth decade of life. The total number (Nt) of these fibers did not show however any significant variation with age or sex: Nt per mm2 of skin surface was 3220±660 (S.D.). We found for all age groups a significant increase of total fiber length by comparing persons between 20 and 30 years with those above 60 years. There was, however, no significant variations according to age or sex for the frequency distribution of mature elastic fiber length and diameter. As a significant decrease with age of the dermal thickness was also found in males and females, the loss of elastic fibers with age is mainly due to a loss of skin thickness (skin volume) with age. This loss is about 30% at 50 years and nearly 50% at 80 years. Loss of skin elasticity with age can be due to loss of cells (fibroblasts), to a decrease of their biosynthetic activity and to qualitative modifications of extracellular matrix macromolecules.

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Total Ki-67 stained area percentage was studied in 32 B and 46 T malignant lymphomas (ML) using two different image analyser systems (TAS, Leitz; SAMBA TM 2005, TITN) respectively. The total Ki-67 area percentage was highly correlated to the number of Ki-67 positive cellular profiles (B-ML, r = 0.93; T-ML, r = 0.88), indicating that area percentage is a reliable alternative method to the manual cell counting. Image analysis allows quicker measurements, appropriate to large and strictly lymphomatous regions. The cell image processor (SAMBA TM 2005, TITN) linked to a color video camera was more suitable for immunohistochemical sections and allowed more automated and faster measurements than the texture analyser (TAS, Leitz) linked with a black and white camera. Alkaline phosphatase technique with fast red as chromogen was more suitable for the detection of Ki-67 stained area by thresholding than peroxidase technique with aminoethylcarbazol or with diaminobenzidine as chromogens. Significant differences were found between low and high grade in B and T ML according to the Kiel classification (mean values +/- SD of 7.7 +/- 3.8% and 16.6 +/- 6.2% in B-ML and of 10.2 +/- 7.9% and 25.6 +/- 16.3% in T-ML respectively). In follicular B-ML, considering follicular areas only, values were comparable to high grade ML; angioimmunoblastic-lymphadenopathy-like (AILD-type) T-ML belonging to low grade ML showed similar values to pleomorphic T-ML with medium and/or large cells belonging to high grade ML.(ABSTRACT TRUNCATED AT 250 WORDS)

Skin ageing was studied with a noninvasive method: indentometry. We measured two rheological parameters: resistance to pressure, indentation, under the pressure of 10 g/cm2, and elastic rebound, elasticity, after the removal of the pressure. We studied three different populations: cloistered nuns, white collar and blue collar workers. We found in all populations a steady decrease in elasticity as a function of age; this effect was always steeper in females. The working women lost their elasticity more rapidly than the nuns, and the male blue collar workers lost their elasticity more rapidly than the male white collar workers. The development of indentation as a function of age is somewhat different. The white collar males showed a steady loss of resistance to pressure with age much more rapidly than their blue collar counterparts. The females showed either a biphasic change (the nuns), no change at all (the white collar workers) or a loss of resistance to pressure (the blue collar workers). These results show that professional as well as social factors may influence skin ageing.