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K Wolff

Publications and source records attributed to K Wolff.

At least 343 records · Page 19Linked to original sources
PubMed1976

Protective action of beta-carotene against lethal photosensitization of fibroblasts in vitro.

Cell culture experiments using haematoporphyrin photosensitized bovine hoof fibroblasts and long-wave uv-irradiation revealed two distinct and separable patterns of lethal photosensitization according to two different sensitization procedures: (1) Photosensitization of cell membranes by short exposure (5 min) of cells to haematoporphyrin. (2) Cytoplasmic photosensitization elicited by a 2 h exposure of cells to haematoporphyrin. Cell membrane photosensitization was reversible by incubation of cells in serum which removed surface bound haematoporphyrin; cytoplasmic photosensitization was irreversible. Beta-carotene was tested in these two systems and the following results were obtained: (1) Preincubation of bovine hoof fibroblasts in beta-carotene protects from lethal haematoporphyrin photosensitization. (2) Protection with beta-carotene is achieved against both types of photosensitization. (3) The protective effect of beta-carotene depends upon the duration of pretreatment, reaching a maximum after 7 days. (4) Beta-carotene protection is maintained even after trypsinization of bovine hoof fibroblasts and withdrawal of beta-carotene from the medium for 24 h or more. (5) Haematoporphyrin sensitized bovine hoof fibroblasts show a distinct pattern of red fluorescence for each type of photosensitization. Incubation of bovine hoof fibroblasts in beta-carotene prior to haematoporphyrin photosensitization results in a pronounced reduction of red fluorescence. Some of these data indicate that beta-carotene acts, at least in cell membrane photosensitization, at the level of the cell membrane into which it appears to be incorporated.

Animals↗
PubMed1976

Control of scrotal colour in the vervet monkey.

The vervet monkey has a vivid blue scrotum which pales when the animal falls in social rank. Histology and electron microscopy showed dopa-positive melanocytes in the dermis each packed with fully melanised melanosomes. By transmitted light the scrotal skin was brown on a red background: by reflected light the colour was blue. Thus the blue colour is due to Tyndall scattering over a layer of melanin. Variation of scrotal colour was not due to changes in melanocyte number or dispersion of melanosomes. Pallor was induced by injecting fluid, and blueness could be restored by removing fluid. It is concluded that the blue-to-white colour variation is modulated by the degree of dermal hydration.

Animals↗
PubMed1976

Experimental induction of hepatocellular hyalin (Mallory bodies) in mice by griseofulvin treatment. 1. Light microscopic observation.

Griseofulvin (GF) feeding of mice resulted in protoporphyria, liver cell damage, bile duct alterations, and finally hepatoma formation. In addition, hepatocellular hyalin developed, resembling in its morphology classic Mallory bodies (MB) as seen in alcoholic and nonalcoholic liver disorders in man. Liver cells containing MB often displayed features of severe cell damage and MB were finally released into the sinusoids and degraded by macrophages. The rapid disappearance of MB following GF discontinuation and the reappearance after resumption of GF feeding suggest an intimate relationship between metabolic alterations in the hepatocytes exerted by the drug and MB formation. This assumption is further supported by the fact that MB change their tinctoreal properties in chromotrope aniline blue-stained sections after GF discontinuation, possibly relfecting degeneration. Long term GF treatment apparently primed the liver for MB formation since the cells were able to respond almost instantly with MB to a GF challenge after a 1-month GF-free period.

Animals↗
PubMed1975

Immunochemical localization of in vivo bound immunoglobulins in pemphigus vulgaris epidermis. Employment of a peroxidase-antiperoxidase multistep technique for light and electron microscopy.

A multi-step immunocytochemical method utilizing horseradish peroxidase (HRP) as an immunological marker was employed to demonstrate, at the ultrastructural level, IgG antiepithelial autoantibodies bound in vivo to pemphigus epidermis, and circulating IgG antibodies, using monkey oesophagus as substrate. To demonstrate IgG the following antisera were employed in sequential steps: Goat antihuman IgG; rabbit antigoat IgG; goat-anti-HRP-serum. After incubating with the final antigen, HRP, the latter was visualized with a cytochemical method. Results paralleled those obtained by immunofluorescence, the antiepithelial antibody being demonstrated at the sites of the intercellular spaces of the epidermis. Electron microscopic cytochemistry showed IgG in the surface coat of epidermal cells and in the intercellular space, both in the desmosomal and the interdesmosomal areas. These results confirm the results of a previous study but the localization of the antibody is more exact than that obtained with HRP-conjugates. The present method is more versatile and specific than HRP methods that utilize HRP-conjugated antibodies.

Animals↗
PubMed1975

[Photochemotherapy of psoriasis: clinical experiences with 152 patients (author's transl)].

Photochemotherapy, a recently developed method of treatment, is based on the effect of light on a systemically administered photo-active substance. 152 patients with severe generalized psoriasis were exposed, after oral administration of 8-methoxy-psoralen, to a high-intensity UVA light source radiating at a continuous spectrum between 320 and 390 nm (maximum at 365 nm). Radiation doses ranged from 1.4 to 4.8 J/cm2 and were progressively increased. Complete remission occurred in 141 patients, satisfactory improvement in the remaining 11. It required 12+/-6 radiation sessions (-/x +/- s) to obtain remission, mean duration of treatment being 22 +/- 14 days. Apart from a neutral ointment no other local or systemic therapy was used. Photochemotherapy completely healed the psoriatic foci leaving evenly tanned, cosmetically appealing skin. All patients were treated at intervals as out-patients (average once a week or ev-ry other week), and remained without recurrence for up to 400 days. No local treatment is required with photochemotherapy, which is very effective, simple, harmless and does not stress patient or doctor. Interval treatment maintained the cure.

Adolescent↗
PubMed1975

Glycocalyx of epidermal cells in vitro: demonstration and enzymatic removal.

Guinea-pig epidermal cells in culture possess a glycocalyx coat similar to that in vivo, as revealed by the ruthenium red stating technique. Trypsin, phospholipase C, and lysozyme do not produce any changes of the glycocalyx, while hyaluronidase and neuraminidase lead to partial and subcomplete removal respectively. Cells stripped of their glycocalyx coat by neuraminidase do not detach from the support and do not show any signs of toxicity. There is complete reconstitution of the glycocalyx within 24 hr.

Animals↗
PubMed1975

Mouse model for protoporphyria. I. The liver and hepatic protoporphyrin crystals.

Outbred albino mice were rendered protoporphyric by a diet containing 2.5% (weight) of griseofulvin. There was a 5-fold increase in liver weight, hepatocellular degeneration and necrosis, cholestasis, ductular proliferation and cirrhosis. Liver protoporphyrin values were elevated and brown pigment granules were present in hepatocytes, Kupffer cells, and bile ducts. The granules showed red fluorescence, birefringence, and, at the ultrastructural level, consisted of aggregates of needle-like crystals. Crystals isolated from such livers showed solubility and absorption characteristics of protoporphyrin; in vitro recrystallization of protoporphyrin, extracted from protoporphyric mouse livers, yielded crystals identical with those observed in vivo, and commercial protoporphyrin exhibited similar morphologic features. The liver pathology and protoporphyrin crystals observed in these animals are identical to the liver pathology and crystals observed in the human disease, erythropoietic protoporphyria. In this mouse model, protoporphyrin crystals are intimately associated with hepatocellular injury and it appears that their accumulation within hepatocytes leads to hepatocellular destruction. A similar pathogenesis is postulated for the hepatic damage that occurs in some cases of erythropoietic protoporphyria.

Animals↗
PubMed1975

Mouse model for protoporphyria. II. Cellular and subcellular events in the photosensitivity flare of the skin.

Acute phototoxic reactions were induced by long-wave ultraviolet light (UV-A) in mice with griseofulvin-induced protoporphyria. The clinical response was characterized by erythema, pronounced edema, and purpura. Tracer experiments and electron microscopy revealed pronounced vascular damage and leakage of vascular contents, whereas the epidermis and all other dermal components were intact. There was selective destruction of endothelial cells and damage of the basal lamina of the vessels. This striking vascular injury was absent from nonprotoporphyric UV-A-irradiated mice and from protoporphyric and nonprotoporphyric mice exposed to short-wave ultraviolet light (UV-B). Patients with erythropoietic protoporphyria (EPP) exhibit an identical, selective damage of blood vessels when irradiated with UV-A or sunlight but not with UV-B alone. It is hypothesized that in both murine protoporphyria and EPP, endothelial cells are photosensitized by protoporphyrin circulating in the serum and that photosensitized endothelia represent the primary cellular target of the photochemical reaction induced by UV-A.

Animals↗
PubMed1975

Staphylococcal toxic epidermal necrolysis: pathogenesis and studies on the subcellular site of action of exfoliatin.

An exfoliating substance elaborated by certain phage Group 2 staphylococci causes toxic epidermal necrolysis. Both in man and in the newborn mouse, intraepidermal cleavage is the predominant histologic feature following exposure to this toxin. Electron microscopic study of sequential biopsy specimens obtained from neonatal mice and from organ cultures of human skin revealed intercellular cleavage and cell separation. The extracellular nature of the exfoliative process was confirmed in several ways: (1) perfused tracers did not penetrate cells during cell separation; (2) cultured cells exposed to high doses of exfoliating fractions demonstrated no signs of injury; and (3) cleaved surfaces examined by scanning electron microscopy and surface replication demonstrated intact plasma membranes. When fractions capable of inducing exfoliation were applied to cultured keratinocytes of fibroblasts, sperm, or lymphocyte suspensions, and to human or mouse skin in vivo, they did not alter the distribution or intensity of concanavalin A binding, ruthenium red staining, pemphigus antibody binding, or HL-A surface antigens. Therefore, while the pathogenesis of staphylococcal toxic epidermal necrolysis involves intercellular cleavage, the molecular cell surface target remains unknown.

Animals↗
PubMed1975

Erythropoietic protoprophyria--submicroscopic events during the acute photosensitivity flare.

The immediate response of erythropoietic protoporphyria (EPP) skin to long-wave ultraviolet radiation (UVR) was studied with the electron microscope. The main finding was severe vascular injury. This was confined to the superficial vessels of the dermis and consisted of endothelial cell degeneration and a pronounced leakage of vascular contents. In contrast, the epidermis showed no abnormalities. Short-wave UV irradiation of EPP skin resulted in epidermal changes typical for the usual sunburn reaction and spared the dermal blood vessels. The following conclusions are drawn: (i) Endothelial cells are the primary cellular target for the photodynamic reaction in EPP. (ii) The fibrillar material, characteristic for chronic EPP lesions, originates from the vessels and vascular contents. (iii) The multilayered basement membranes observed in such lesions reflect multiple consecutive reparative processes that follow endothelial injuries.

Adult↗
PubMed1975

Liver inclusions in erythropoietic protoporphyria.

Needle-like inclusions have been found, by electron microscopy, in the livers of two unrelated patients with erythropoietic protoporphyria. Since they have not been noted in other hepatic conditions but do occur in the livers of protoporphyric mice it is suggested that they represent markers for protoporphyric liver disease. Paracrystalline inclusions that have been previously described in Wilson's disease and porphyria cutanea tarda were also present in the hepatocytes of one of these patients.

Adult↗
PubMed1975

Hepatocellar hyalin (Mallory bodies) in long term griseofulvin-treated mice: a new experimental model for the study of hyalin formation.

Experimental studies on the significance and origin of hepatocellular "alcoholic" hyalin (Mallory bodies) are hampered by the lack of a suitable animal model. In the present paper, the experimental production of hepatocellular hyalin identical with human alcoholic hyalin both light and electron microscopically in long term griseofulvin-treated mice is described. Moreover, the results conclusively disprove the specificity of Mallory alcoholic hyalin for alcohol-induced liver cell damage.

Alcoholism↗