Multiple clear cell acanthomas. A clinical, histological, and ultrastructural report.

A case of multiple clear cell acanthomas in a 64-year-old woman is reported. The clinical and histological findings of this rare entity are consistent with the hypothesis that clear cell acanthomas are benign epidermal tumors. An ultrastructural study was performed with special emphasis on the melanocytic-keratinocytic interaction.

Glutathione reductase in human epidermal tumors. Basal and squamous cell epithelioma, verruca seborrhoeica.

Glutathione reductase activities, both with NADPH and NADH, were determined in basal and squamous cell epitheliomas, in verrucae seborrhoeicae and in human epidermis. Significantly elevated activites were measured in basal cell epitheliomas and in verrucae seborrhoeicae. Some properties of the enzyme were also investigated.

Glutathione in human epidermal tumors. Basal and squamous cell epithelioma, verruca seborrhoeica.

Methods for the determination of glutathione in small epidermal and tumor fragments are compared. The best results were obtained by an enzymatic cycling technique. The total glutathione concentrations in basal cell epithelioma, squamous cell epithelioma, and verruca seborrhoeica were 2.08, 1.81, and 1.87 mg/g dry weight, respectively. In normal epidermis adjacent to the basal cell epitheliomas the concentration was 1.27 mg/g dry weight.

Nuclear differentiation and ultimate fate during epidermal keratinization. Two-wavelength and cytofluorometric DNA investigations completed by computerized scanning image analysis.

Quantitative DNA cytophotometric investigations were performed to clarify some aspects of the differentiation and fate of nuclei in bovine snout and human epidermis representing various sites and different degrees of keratinization. We elaborated optimal conditions for hydrolysis and Feulgen staining. Diverse cytophotometric techniques, including computerized scanning cytophotometry and image analysis were applied. This approach provided the first quantitative data concerning changes of nucleotype during soft keratinization. Cytophotometric DNA measurements provide evidence for a continuous decline of nuclear DNA content from immediately beyond the basal layer to the transition zone. The overall loss of DNA is an orderly process that intensifies gradually and culminates in the stratum granulosum. Gradual nuclear degeneration, however, is not a general phenomenon, and a significant number of nuclei retains a DNA content within the diploid limits throughout the entire stratum spinosum and part of the stratum granulosum. At any level of differentiation or decay, residual nucleoprotein complexes remain intact, as judged from their resistance to acid hydrolysis. Karyological features change completely during keratinization. Basal cell nuclei are rather compact, ellipsoid and heterochromatic. Beyond the basal layer, nuclei enlarge, round up and obviously evolve to an extremely euchromatic state, with preferential localization of the dispersed heterochromatic clumps at the more peripheral sites. In the upper stratum spinosum, nuclei undergo even more drastic changes: nuclear area and volume shrink, nuclei partially regain the ellipsoid shape and revert to heterochromasia. Nevertheless, euchromatin remains the major constituent of decaying nuclei. Terminal differentiation stages, except in human sole, are marked by heterochromatin clumping. In human sole, persistence or even progression of heterochromatin dispersion is observed. Heterochromatic dots are situated along the nuclear membrane in human terminal keratinocytes, but are almost randomly distributed in bovine stratum granulosum nuclei. Finally, nuclear contrast analysis partially reveals statistically significant changes throughout keratinization.

An immunohistochemical and histochemical study of cytokeratin, involucrin and transglutaminase in seborrhoeic keratosis.

The mode of differentiation of seborrhoeic keratoses was investigated by immunohistochemical staining using cytokeratin (CK) polypeptide-specific monoclonal antibodies and an antibody specific for the particulate form of epidermal transglutaminase (ETgase), and by applying an anti-human involucrin serum. The role played by (E)Tgase was further evaluated using an activity assay based on the covalent attachment of monodansylcadaverine. Samples of uninvolved epidermis served as reference tissue. CK reactivities suggested that seborrhoeic keratoses is a hyperproliferative disease with an epidermal CK composition. CK5 and CK14 were prominent markers of basal and basaloid keratinocytes, whereas a decrease in staining occurred in advanced maturation stages and areas of terminal keratinization. In contrast, CK1 and CK10 were prominent markers of suprabasaloid differentiation stages and produced complementary stainings to those of CK5 and 14. Generally, CK10 staining was more impressive than CK1 staining and seemed to start before CK1 staining. In contrast to CK10 staining, cornified areas lost CK1 reactivity. These staining patterns were similar to those observed in uninvolved reference tissues. The epidermal CK subset was further supplemented with the 'hyperproliferative' CK6 and 16 which occur sequentially. Positive staining for CK6 was noted from basal and proximal basaloid cells onwards, whereas distal basaloid cells additionally showed CK16 staining. The presence of other non-epidermal CK polypeptides could not be shown. The competence for other differentiation markers belonging to the group of (E)Tgase and cornifying cell membranes also evolved with a typical epidermal pattern. (E)Tgase activity was restricted to advanced and terminal stages of keratinization and was dual in nature, i.e. a diffuse cytoplasmic staining occurred together with a prominent staining of cornifying cell membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

An investigation of cytokeratin expression in skin epithelial cysts and some uncommon types of cystic tumours using chain-specific antibodies.

The differentiation state of skin epithelial cysts and some uncommon types of epithelial skin tumours was investigated by immunohistochemical staining, mainly using cytokeratin (CK) polypeptide-specific monoclonal antibodies. Samples of interfollicular epidermis, hair follicles and eccrine sweat glands were included as reference tissues. The CK reactivity in epidermoid cysts and milia is not restricted to CKs involved in epidermal-type differentiation, i.e. CK1, 5, 10 and 14, but in addition CK16, a hyperproliferative keratinocyte marker is suprabasally expressed. CK1 and 10 are other prominent suprabasal markers, while CK14 seems to be preferentially expressed in the basal cell layer. Of the non-epidermal CKs, only CK4 was focally or more extensively detected in about 50% of the cases. In terms of CK reactivity, keratinization of trichilemmal cysts corresponds to the keratinization of the anagen-phase hair follicle in the isthmus. The CK reactivity is again restricted to CK1, 5, 10, 14 and 16. However, the CK1 as well as CK10 reactivity is subject to serious limitations, since both CKs were only convincingly observed in foci of terminal differentiation. Eccrine hydrocystoma obligatorily expresses a complex CK set, including CK7, 8, 14, 18 and 19. This CK set perfectly corresponds to the CK composition observed in acini of eccrine sweat glands. In addition, a discontinuous CK4 and 16 reactivity was seen in about 50% of the sites, while CK1 and 10 displayed a strictly focal appearance. On the other hand, syringoma produces in its distinct structures, a CK pattern reminiscent of the one observed in eccrine sweat gland ducts and includes CK1, 5, 10, 14, 16 and 19.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of acitretin.

Acitretin, the metabolite of etretinate, is eliminated far more rapidly from the human body than is etretinate. It has therefore been suggested that only a short period of contraception would be required following the completion of long-term therapy. However, recent studies have demonstrated the presence of etretinate in the plasma of acitretin-treated patients. In this paper, we review the results of studies at our centre in view of the recently discovered metabolic pathways for acitretin. Re-esterification of acitretin to etretinate, however, results in a loss of the metabolic advantages of acitretin. Because of this new knowledge, the recommended contraception period after acitretin therapy has been lengthened to 2 years.

A retrospective study of the inpatient treatment of psoriasis with dithranol.

This study reports the results of the Ingram dithranol regimen for the treatment of psoriasis in 275 inpatients. The median duration of hospitalization until clearance was 25 days and the medians of the interval until a next treatment or hospitalization was needed were 11 and 8.5 months, respectively.

Dose measurement in PUVA therapy.

The dose emitted by the fluorescent tubes used in PUVA therapy is not constant: it varies in function of time, age of the lamps, and several other factors. Exact knowledge of the dose given to the patient requires continuous measurement and integration of the UV-A output.

[Biochemistry of elastin]. / Biochemie des Elastin.

The recent findings on the composition and synthesis of elastin are presented. Particular attention is paid to the various specific cross-links and to their formation from lysine residues in the polypeptide chains.