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Copyright of Der Hautarzt is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electron microscopical investigations of untreated solar keratosis, squamous cell carcinoma, and Bowen carcinoma showed intranuclear bundles of intermediate filaments in suprabasal keratinocytes. We found evidence that the filaments are incorporated into the nucleus during atypical mitosis. [ABSTRACT FROM AUTHOR]

Although cyclosporin is effective in immunosuppression following organ transplantation and in the treatment of psoriasis, its use is limited by its side-effects, notably impaired renal function and hypertension. As SDZ IMM 125, a new derivative of the cyclosporin family, showed considerable immunosuppressive activity in experimental studies, with less effect on renal function, it was considered a potential successor to cyclosporin for both indications. In this multicentre, double-blind, placebo-controlled study, the efficacy and tolerability of 40, 100, 200 and 400 mg SDZ IMM 125 daily were studied in 59 patients with psoriasis. Patients were followed for a period of 5 weeks (4 weeks treatment, and 1 week post-treatment observation). A dose-dependent effect of SDZ IMM 125 was observed. A significant correlation was found between the dose of SDZ IMM 125 and changes in the sum of severity scores of three indicator plaques. There was a significant decrease in the body surface area affected by psoriasis in the 400-mg group (P ≤ 0.01), whereas a decrease of the global psoriasis severity was observed in the 200-mg (P ≤ 0.01) and the 400-mg groups (P ≤ 0.001). No serious adverse events occurred during the 4 weeks of treatment. Three patients discontinued treatment because of adverse events (one sore throat, two influenza). Clinical adverse events were similar to those reported with cyclosporin, the most frequent being gastrointestinal disturbances. Estimation of renal function indices showed that increases from baseline values were dose-dependent, and appeared to be similar to those seen with cyclosporin. Changes in liver function tests showed a clearcut dose-dependent increase of some liver enzymes, principally alanine aminotransferase (ALAT). SDZ IMM 125 is effective in clearing psoriasis. However, long-term studies comparing the efficacy and safety of SDZ IMM 125 and cyclosporin must be performed, to determine whether SDZ IMM 125 has a better risk-benefit ratio than cyclosporin. [ABSTRACT FROM AUTHOR]

The in vitro effects of liposomes on HaCaT humph keratinocytes were studied with regard to their uptake, lipid fluidity and proliferation of the cells. Oligolamellar liposomes, prepared from soya bean phospholipids, had a mean size of 150 nm and consisted predominantly of phosphattdylcholine (83%) and phosphatidylethanolamine (10%) and the fatty acids comprised mainly linoleic acid (66%) or other unsaturated fatty acids. After 6 and 24 h of incubation with I and 0.1% w/v of liposomal lipids, phase-contrast microscopy revealed marked cytoplasmic vacuolization of the cells. Keratinocytes treated with the liposomes contained aggregations of multilaminated lipid material without delimiting cell membranes. The cellular lipid fluidity (reciprocal of diphenylhexatriene fluorescence polarization P-value) correlated with liposomal concentration and incubation time. A significant elevation of lipid fluidity (P < 0.05) was observed with I and 0.1% liposomes after 1 h of incubation (81.84 ± 4:7 and 95.7 ± 1.2% of control P value) and for 0.01% liposomes alter 3 h (96.24 ± 5%). Maximum fluidity occurred alter 48 h of exposure to 1% liposomes (42.1 ± 3.1%). Exposure to liposomal lipids for 24 and 48 h resulted in suppressed cell proliferation with 50% inhibition concentrations (IC50), being 0.06% for incorporation of [³H]-thymidine. 0.08% for [14C]-amino-acid corporation and > 1% for protein content per well after 24 h of exposure. The cells were able to proliferate and lipid fluidity returned to normal within 7 days following discontinuation of incubation with liposomal lipids. [ABSTRACT FROM AUTHOR]

The article reports that membranes are complex layers of proteins, lipids and carbohydrates. They are semipermeable and build up gradients of concentrations which are necessary conditions for life. Polar lipids, in the main part phospholipids, are arranged in a laminar bilayer, directing their polar hydrophilic head groups to the outer acquous phase and their non-polar hydrophobic groups to the inside of the membrane. The lipid component is suggested to be in a viscous state, so that proteins are able to disperse according to functional parameters.

This study has been undertaken to elucidate the localization and the activity of cyclic nucleotide phosphodiesterase (PDE) in psoriatic epidermis compared to normal. The results showed that the evaluation of cytochemical methods may be difficult because of the various factors which interfere with the reaction and the considerable amount of background staining. Additionally, only the tissue bound particulate enzyme fraction may be demonstrated by cytochemical means. Nevertheless, the method did reveal that the activity of PDE, if any, is localized on the cytoplasmic membranes of the cells, independent of their origin, and not on the cell surface. Moreover, no differences were found between normal and psoriatic skin. It seems, therefore, that the intracellular degradation of cAMP remains unaltered in psoriasis. [ABSTRACT FROM AUTHOR]

The total membrane-bound ATP hydrolytic activity in human epidermis is due to the activities of at least three differently located enzymes, namely Mg++-activated ATPase, phosphomonoesterase and adenyl cyclase. Cytochemical studies on psoriatic epidermis with various inhibitory and stimulatory substances showed reduced activities of ATPase and phosphomonoesterase, and a lack of sensitivity of adenyl cyclase to specific stimulators such as isoproterenol and glucagon. Since no differences of basal adenyl cyclase activity were observed between normal and psoriatic human skin without stimulation, it seems likely that in psoriasis a latent defect of adenyl cyelase may exist, resulting in a deficient response of this enzyme to regulatory agents. In conclusion, the present study reveals that not a single enzyme but the entire membrane-bound nucleotide metabolism is altered in psoriatic keratinocytes, causing a disturbance of the membrane-bound energy utilization, similar to findings in proliferating tumour cells. [ABSTRACT FROM AUTHOR]

Previous studies from our laboratory suggested that architectural alterations of the cell membranes may have a major significance in the pathogenesis of psoriasis. Consequently, the membrane-bound Mg++ activated ATP-hydrolytic activity was investigated in normal and psoriatic epidermis under the electron microscope. The present study revealed that, in contrast to normal epidermis, only minimal ATP-hydrolytic activity is present on the cell membranes of psoriatic keratinocytes. This finding may reflect either a diminished attachment of substrate on the altered cell surface or an enzyme defect of the cell membrane a In both cases the reduced interaction between ATP and membrane-bound ATP-hydrolysing enzymes represents a functional membrane disorder of the psoriatic keratinocyte, presumably resulting in an insufficient utilization of ATP for active transport mechanisms on the cell surface. [ABSTRACT FROM AUTHOR]

Both auricles of 21 domestic rabbits were painted with dimethylbenz-anthracene (DMBA). Eleven animals of this group were additionally fed aromatic retinoid (AR) by an esophageal tube. Two control animals were not treated at all. Eight or 9 weeks after the beginning of the study six of the seven remaining animals, which had only been painted with DMBA, developed a total of 25 keratoacanthoma-like tumors (KA). On the other hand, none of the seven animals left, which were painted with DMBA and fed AR showed any tumor by this time. The systemic effect of AR was studied in biopsies from the snout and the back. The epidermis of the snout showed 'mucous mataplasia' by histochemical and electron-microscopic criteria, whereas the epidermis of the back was not significantly altered. The production of intra- and extracellular lamellated material indicated an additional effect of AR on epidermal lipid metabolism. The effect of AR in the prevention of DMBA-induced tumors was characterized by 'mucoid cytolysis' and karyolysis. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Dermatological Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)