© 1995 Vevy Europe Photoimage Human skin. Histochemical reaction to localize enzyme alkaline phosphatase activity. Reactivity is essentially localized in the dermal hair component (papilla and cuticle), since keratinocytes are deprived of such enzyme. The capillaries are red stained, especially those in active proliferation. The dermal papilla, rich in alkaline phosphatase, is sranding out because the hair section is in anagen phase in which this organule is in its highest development and trophism stage. Magn. 300x

© 1995 Vevy Europe Photoimage Cutis of 80-year-old man. Hematoxylin-eosin. Magn. 500x.

© 1995 Vevy Europe Photoimage Mast cells or Mast-zellen. Giemsa Staining. Magn 300x. Ear section from normal mouse (skin of Balb/C) A line of globoid cells with large empty spaces inside can be observed at the bottom. They are chondrocytes, i.e. cartilage cells of the pinna. At the top, the skin can be seen, stained in pink, with s ebaceous glands (in the middle), hairs, fibroblasts and mast cells. The latter cells are easily detectable because of the purple colour they acquire when stained with Giemsa, due to metachromasia. In this specimen, mast cells have a normal shape with a homogeneous distribution in the skin. They are in a patrolling state, though no inflammation is under way. The purple stain of these cells is expressed by va soactive substances contained in their vacuoles and released when stimulated by antigens or inflammatory factors. Rashes, burning and swelling of inflamed parts are mainly due to these cells that, with their substances, amplify the response against harmful agents. They allow greater blood flow to supply the damaged area with abundant plasma proteins to ensure immune defense.

© 1995 Vevy Europe Photoimage Cutis of woman aged 45. Giemsa Staining Magn. 500x. Cutaneous fold with rather thin epidermis. This stain not only shows the cellular structure but also melanin which turns green due to metachromasia typical for this stain. Almost all the epithelial cells of the basal layer in this skin segment feature this pigment. It is not limited to melanocytes but also extends to normal epithelial cells which have ahsorbed the pigment from the latter. The skin indeed is tanned.

© 1995 Vevy Europe Distribution pattern of the arterial, venous and lymphatic plexus of the skin. 1. Papillary capillaries; 2. dead-end starting lymph capillaries; 3. lymph branch of the superficial lymphatic plexus; 4. candelabrum-shaped communicating branches debouching into the dermal papillae; 5. supe rficial venous plexus; 6. hair with its follicle and its vascularized venous and artery branches of the superficial plexus; 7. primary arteries and veins of the vasal plexus profundus; 8. lymph collector of the lymphatic system of the superficial plexus; 9. primary artery branch originating the artery plexus profundus; 10. venous and artery branches descending towards the subcutaneous adipose lobuli. In the papillary section, the lymphatic system is a closed systerm: consequently, the lymph circulates, in the first instance, outside the lymphatic system, directly bathing the dermic elements: this is the "plasmatic circulation" wh ich constitutes the internal means allowing nutritional exchange to take place. The plasmatic circulation which regulates the lymphatic circulation, is under the influence of the blood circulation; its exudation is regulated by blood pressure and by the o smotic pressure of fluids, by nervous influences, endocrine influences, cellular metabolism, by the state of constriction and dilation of the vessels, and finally by the release of H vasodilatory substances emitted in large amounts by irritated cell tissu e.

note: click the image to zoom in

© 1995 Vevy Europe Photoimage Cutis of a guinea pig. Staining Azan Mallory, Magn. 500x. This methodology requires the utilization of two dyes: nuclear red and blue selectively staining the collagen fibers. The photo shows the uniformely pink stained epidermal layer and the bright red horny layer, whereas the dermis is blue stained. So me reddish fibroblast nuclei and endothelial cells pertaining to the capillaries of the dermis can also be observed. In this picture, it is interestig to observe that the basal layer is entirely consisting of cylindrical cells, while the spinous layer has pcrfectly round nuclei, clearly featuring densifled chromatin nuclei (forming tiny red dots), most of which r epresent RNA messenger segments and, to a lesser extent, DNA segments.

© 1995 Vevy Europe Photoimage Cutis of a woman aged 55. LAP reaction after 50 minutes. Epidermis and dermis: intense red granular (lysosomial) reaction of the dermal fibroblasts. This enzyme proves the existence of an intensive peptidase activity in these elements derivi ng from complex proteolysis and proteosynthesis phenomena. Magn. 1250x.

© 1995 Vevy Europe Photoimage Cutis of a man aged 60. LAP reaction after 60 minutes. Dermal papilla. Some fibroblasts with strongly reacting long cytoplasmatic fibers are clearly visible. No LAP activity in the epidermis. Magn. 1250x.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 200. Alpha-napthil esterase reaction 33 minutes. Epidermis and dermis. The enzimatic activity of skin is localized in the stratum granulosum which seems marked by a continuous red-brown strip. That means that th ese cells have a great production of enzyme, even if they are in their penultimate phase of life. We can also see many melanocytes in the stratum germinativum: here the staining is only due to their pigment. All nucleous are stained by methil green.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Alpha-naphtyl esterase reaction, 20 minutes. Skin fold in clavear area. The reaction in the stratum granulosum is less intense than in the former photo (Fig. 1), because the incubation time is less: 20 min utes instead of 33. Many melanocytes full of melaninic granules are disposed along the basal membrane. The presence of esterasic enzymes in the cells of the stratum granulosum is connected with their process of keratinization.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Alpha-naphtyl esterase reaction, 20 minutes. Cutaneous crest, it is evident the positivity of the stratum granulosum. The nucleous of this layer are placed longitudinally; all the cytoplasm is brown throug h the precipitation of pararosaniline, that is a diazo reagent which reveals the enzimatic activity points. The layers below are not reactive for this enzyme and the stratum corneum not even.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Alpha-naphtyl esterase reaction, 20 minutes. Group of about ten melanocytes with melaninic granules. The stratum granulosum is stained with pararosaniline which evidentiates the places were the enzymatic a ctivity is.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 500. Alpha-naphtyl esterase activity, 30 minutes. Sweat eccrine gland of the clavear area. The ducts are composed of a double layer of cuboid cells marked by the activity. Above we can see some duct sections mor e reactive. The cells here have a reabsorbtion tuch and perhaps they need a greatest quantity of enzyme. The enzymatic activity is connected with physiological cellular activity.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Alpha-naphtyl esterase activity, 30 minutes. With a greatest magnification it is visible the difference between the activity of the secretory portion (down) and these of the escretory duct (up). The last c an be distinguished for its greatest activity evidentiated by a dark brown staining. Green stain of the nucleous is due to methil green.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Alpha-naphtyl reaction, 30 minutes. The section cuts an hair-sebaceous formation in eruptive phase. Activity is concentrated in the neck of the sebaceous gland and in the epithelial cells standing up the h air in growth phase, were the further hair duct will pass. Epiderm under hair push has bend. We can see down in the photo a sweat gland.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 500. Alpha-naphtyl reaction 30 minutes. With a greatest magnification of the precedent photo (Fig.7) we see the confluence point of the hair part and of the sweat connected gland. Hair bulb has a tidy stratum ge rminativum, the glassy membrane is visible and the hair cavity also. Activity is evidentiate with red-brown staining of pararosaniline, it is situated in the epiteliocytes overhanging the hair and where the cuct is going to form. This indicate a great cel lular activity in this point during the eruptive phase.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 500. Alpha-naphtyl reaction 20 minutes. Root of a developed hair. There is no activity in the epithelial cells of the hair duct. The allonged positive cells (brown with green nucleous) along the hair are macroph ages. They are disposed in a strategical way in the point of less cutaneous defence; in fact hair determin an interruption of the dermic barrier. We can easily see some melanocytes in the hair bulb. Down in the photography is a sweat gland.

© 1995 Vevy Europe Photoimage Skin of a 50 years old man. X 1250. Giemsa staining. Sweat eccrin gland. The section cuts many tubules. There are visible somewhere metacromatic and birifrangent granules in the epitheliocytes of the secretory part.

© 1995 Vevy Europe Photoimage Cutis of woman aged 20. ATPase reaction after 5 minutes. The epidermis is essentially but not uniformly stained by the reaction at stratum germinativum level (brownish-black precipitates, green nuclei). Langerhans cells are observed among th e positive suprabasal cells. The path of the black stained vessels can be easily followed in the dermis. Magn. 300x.

© 1995 Vevy Europe Photoimage Cutis of woman aged 20. ATPase reaction after 5 minutes. Epidermis. The alignment of the germinative cells on the basement mambrane can be observed. The cells in the centre are stained blackissh-brown by the lead sulphide precipitate located in the ATPase activity site, in the apical zone of the cell. Magn. 1250x.

© 1995 Vevy Europe Photoimage Cryostatic section of mouse miocardium. 20 min. SD reaction. The strong blue staining is given by the succinic dehydrogenase reaction whose concentration is highest in this tissue. The muscle fibrocell pattern can be identified: each blue do t corresponds to a fully active mitochondrion which, adjacent to contractile filaments of the muscle cells, yields energy for contraction. The unstained area at the centre of the picture corresponds to a coronary vessel. Smooth muscle cells of the artery muscular tunica can be observed with the shape of blue commas. They also contain blue SD reaction stained mitochondria. Magn. 300x.

© 1995 Vevy Europe Photoimage Cryostatic section of mouse skin. 60 min. SD reaction. In this low magnification picture the following elements can be identified from bottom to top: a layer of muscle tissue, in blue; just above it deep derma with a good number of longitudi nally arranged (rose-shaped) fibroblasts; then the surface derma and pilosebaceous complexes with SD activity and finally the epidermis. In the skeleton muscles, at the bottom, several cell groups can be identified having different blue intensity. This is due to a non simultaneous contraction of muscle fibres which, therefore, have different energy requirements and enzymatic complement. Fibre contraction is limited in time. During the resting stage, adjacent fibres contract. Thus the strong blue staining characterizes a fibre under contraction, whereas lighter colours indicatenon contracted fibres. Magn. 125x.

© 1995 Vevy Europe Photoimage Human hair. 60 min. SD reaction. The pulled out hair has a sheath of epidermal cells adhering to the shaft and still fully active. The SD reaction, indicated by blue dots, proves this. With time, these cells die and gradually lose the enzyma tic activity investigated here. Activity decrease depends on time and it can be employed for biological dating. If applied when the hair is pulled out, this method shows hair functional condition and any related pathologies. Magn. 25x.

© 1995 Vevy Europe Photoimage Untreated cutis of a 70 days old mouse. The brownish-red colour shows the localized reaction of the horny layer, the green coloured cell nuclea are revealed by a contrast dye. You may notice the two piliferous twin formations originating fro m the same dermal papilla. The reaction involves the two hair shafts. Acid phosphatase reaction, 80 minutes, 300x.

© 1995 Vevy Europe Photoimage Cutis of a 70 days old mouse treated for one week with Oil-1. The almost complete absence of enzymic activity may be noticed as shown by the red (pararosaniline) dye, both in the horney layer and in numerous piliferous formations in the derm a. You may notice the absence of keratin matter (dandruff) in exfoliation phase. Acid phosphatase reaction, 90 minutes, 200x.

© 1995 Vevy Europe Photoimage Human skin. 80 year old woman. X 1250. Acid phosphatase reaction. 60 minutes. Pararosaniline fixes in the place where the enzymatic activity is and stains with a red colour the deepest cells of the stratum corneum. Note the evident differenc e between weak stained epidermis, compared with the stratum corneum, and dermis completely unstained by the eaction.

© 1995 Vevy Europe Photoimage Human skin. 25 year old man. X 500. Acid phosphatase reaction, 60 minutes. Cutaneous crest. The acid phosphatase activity is localized in the same places as in the case of fig.1 and with the same intensity. In green tint, you can see the nuc leous of thee cells stained with methyl green.

© 1995 Vevy Europe Photoimage Human skin. 80 year old woman. X 1250. Acid phosphatase reaction, 50 minutes. Evident positivity of the stratum corneum in the deepest cells of this layer still maintains a cellular individuality. In the lower part of the picture, in the str atum germinativum some melanocytes (cells with brown granules) containing their tipical pigment can be seen.

© 1995 Vevy Europe Photoimage Human skin. 80 year old woman. X 200. Acid phosphatase reaction, 70 minutes. Superficial part of sweat glands. You can notice an intense acid phosphatasic activity around the two pores (two little red rings). The positive elements belong to the stratum corneum.

© 1995 Vevy Europe Photoimage Human skin. 80 year old man. X 1250. Acid phosphatase reaction, 70 minutes. Particular of sweat glands. The enzymatic activity is localized in the cells around the pore. The glandular outlets are in a little grove of skin.

© 1995 Vevy Europe Photoimage Human skin. 25 year old man. X 400. Acid phosphatase reaction, 50 minutes. Eccrin sweat gland. The reaction marks the whole glandular epithelium (stained in pink). On left, down in the picture, you can see the section of an artery whose tona cae are unstained by the reaction.

© 1995 Vevy Europe Photoimage Human skin. 25 year old man. X 1250. Acid phosphatase reaction, 70 minutes. Section of hair follicle. The greatest reactivity is in the medulla. Nucleous stained in green.

© 1995 Vevy Europe Photoimage Human skin. 80 year old woman. X 500. Acid phosphatase reaction, 50 minutes. Section of a hair follicle. Here the reaction is in the medulla of the hair marked by a red stain. The other layers of the hair are visible thank to methyl green wh ich marks the nucleous of cells.

© 1995 Vevy Europe Photoimage Skin of a guinea-pig. X 500. Acid phosphatase reaction, 50 minutes. Section of hair follicle. As in human subjects (Fig. 7-8) the activity is localized in the medulla that appears stained in red for the presence of pararosaniline and it is a lso stained in brown for the presence of melaninic pigment.

© 1995 Vevy Europe Photoimage Skin of a guinea-pig. X 125. Acid phosphatase reaction, 50 minutes. In the centre of the photo we can see the hair stalk. The reaction is visible in the external root sheath. In this section there are many dermal papillae. The stratum germin ativum is marked by many melanocytes with their dark pigments. In the derma there are many macrophages stained in red by the reaction.