Search PubMed⌕ Search

Biomedical subjects

C E Orfanos

Publications and source records attributed to C E Orfanos.

At least 19 recordsLinked to original sources
PubMed1997

Translation initiation factor eIF-4A1 mRNA is consistently overexpressed in human melanoma cells in vitro.

The oncogenic potential of translation initiation factors (eIF-4E and eIF-2alpha) has been described in previous studies leading to the definition of translational oncogenes. Two previously isolated cDNA clones, expressed differently in human melanoma cells and normal human melanocytes, were identified in this study as coding for the translation initiation factor eIF-4A1. Northern-blot analysis revealed consistent overexpression of eIF-4A1 mRNA in a panel of 14 melanoma cell lines (on an average 5.6 times higher than in cultures of normal human melanocytes). In contrast, the mRNAs of the other group-4 translation initiation factors (eIF-4A2, eIF-4B, eIF-4E and eIF-4gamma) were less and not consistently elevated. Cultures of congenital melanocytic nevi exhibited intermediate expression of eIF-4A1. Thus, eIF-4A1 overexpression seems to be an important feature of melanoma cells and might contribute to their malignant transformation.

Base Sequence↗
PubMed1997

1alpha,25-dihydroxyvitamin D3 induces sphingomyelin hydrolysis in HaCaT cells via tumor necrosis factor alpha.

Treatment of the human keratinocyte cell line HaCaT with 1alpha, 25-dihydroxyvitamin D3 (1,25-(OH)2D3) resulted in the hydrolysis of sphingomyelin with peak elevations of ceramide levels after 2-3 h (Geilen, C. C., Bektas, M., Wieder, Th., and Orfanos, C. E. (1996) FEBS Lett. 378, 88-92). In the present paper, the mechanism underlying the effect of 1,25-(OH)2D3 on sphingomyelin hydrolysis was investigated. Using the cell culture supernatant of HaCaT cells treated with 1,25-(OH)2D3 for 2 h, it was possible to induce sphingomyelin hydrolysis as early as 30-60 min after addition to resting cells. Several lines of experimental evidence indicated that tumor necrosis factor alpha (TNFalpha) mediates sphingomyelin hydrolysis after 1,25-(OH)2D3 treatment: (i) 1,25-(OH)2D3 stimulated TNFalpha mRNA expression after 1 h, (ii) newly synthesized TNFalpha occurred 2 h after 1,25-(OH)2D3 treatment, (iii) indirect activation of sphingomyelin hydrolysis by the supernatant of 1, 25-(OH)2D3-treated HaCaT cells was abolished by preincubation of the supernatant with antibodies directed against TNFalpha, and (iv) preincubation of HaCaT cells with neutralizing antibodies directed against the 55-kDa receptor of TNFalpha blocked the ability of 1, 25-(OH)2D3 to induce sphingomyelin hydrolysis in HaCaT cells. These data demonstrate that 1,25-(OH)2D3 activated sphingomyelin hydrolysis by an autocrine mechanism via TNFalpha expression. Furthermore, this indirect mode of action may serve as an explanation for the delayed induction of sphingomyelin hydrolysis by vitamin D3.

Calcitriol↗
PubMed1997

[Mollusca contagiosa in HIV infection. Clinical manifestation, relation to immune status and prognostic value in 39 patients].

Mollusca contagiosa predominantly affect children; their occurrence in adults is rare. In recent years many descriptions of mollusca contagiosa in immunosuppressed patients, mostly in HIV-infected individuals, have appeared. We analysed the occurrence of mollusca contagiosa in a large group of HIV-patients and examined their relation to the immune status and their prognostic significance. 456 patients with HIV-associated skin disorders were documented in the HIV follow-up clinics at the Department of Dermatology, University Medical Center Benjamin Franklin, Berlin, during the years 1982-1992. Molluscum contagiosum was diagnosed in 39 patients (8.6%). 38 of the 39 patients were homosexual and/or bisexual men. The median age of the patients was 34 years. Large, papular and nodular lesions up to 1 cm in diameter were observed in some, individuals. Frequently, multiple lesions in atypical localizations such as the face were found. Significant immunosuppression was present in the majority of patients with mollusca contagiosa at the time of their first diagnosis; median CD(4+)-T-lymphocyte count was 122/microliter and the median CD4+/CD(8+)-ratio was 0.2. The median survival time was 12 months in patients with mollusca contagiosa. There was no significant difference between the prognosis of patients with mollusca contagiosa and other HIV-infected patients showing similar reduction of their immune status. Our study showed that mollusca contagiosa are a rather frequent infection in HIV-patients. Mainly localized to the face, they are easily diagnosed and may serve as an excellent clinical marker for recognizing advanced immunosuppression in HIV-infection. Survival prognosis of patients with molluscum contagiosum is unfavourable, corresponding to their reduced immune status. The presence of mollusca, however, is not an independent prognostic marker, if the immune status is considered.

AIDS-Related Opportunistic Infections↗
PubMed1997

[Superior vena cava syndrome. Description of 3 cases and review of the literature].

Superior vena cava syndrome (VCSS) develops because of a progressive reduction of venous return from the head, neck and the upper extremities. The presenting sign of this relatively rare condition is often a rapidly developing, often massive facial edema. As a consequence, such the patients are often seen initially by a dermatologist. Other clinical characteristics may include cyanotic facial erythema, dilatation of the neck veins, and a prominent venous pattern n the anterior chest. Today, primary lung cancers and other mediastinal tumours represent the most common cause of VCSS, which may take a slowly progressive or a more fulminant course. In these cases, the disease develops rapidly and becomes life-threatening, requiring intensive medial diagnosis and care. We describe three patients with superior vena cava syndrome due to a) bronchogenic carcinoma, b) bihilar sarcoidosis and c) metastasizing malignant melanoma. Since recognition of VCSS broadens the diagnostic spectrum of the dermatologist, an overview on its diagnostic and therapeutic implications is given based on our cases and the literature.

Aged↗
PubMed1997

The phospholipid analogue hexadecylphosphocholine (HePC) inhibits proliferation of keloid fibroblasts in vitro and modulates their fibronectin and integrin synthesis.

Hexadecylphosphocholine (HePC), a topically effective compound, exerts a strong antiproliferative effect on neoplastic cells. In the present study we investigated (1) the antiproliferative effect of HePC on benign mesenchymal cells in vitro, using as examples normal and keloid fibroblasts, and (2) the influence of HePC on various functional properties of these cells, including phosphatidylcholine biosynthesis, their capacity to reorganize a three-dimensional collagen-I matrix, and their expression and synthesis of fibronectin and subunits of the beta 1 integrin family. Fibroblasts derived from keloids (kelfib) and from normal skin (nfib) were cultured in serum-containing medium and treated in the third passage with 50 mumol/l HePC. Proliferative activity was significantly (P < 0.05) more strongly inhibited in kelfib than in nfib under HePC treatment, whereas their phosphatidylcholine synthesis was inhibited to a similar extent. However, the ability of fibroblasts to contract a three-dimensional collagen-I lattice was significantly (P < 0.05) enhanced only in kelfib treated with HePC. These functional differences following treatment with HePC were paralleled by an upregulation of the alpha 2- and beta 1-integrin chains, and a downregulation of fibronectin synthesis and the alpha 5-subunit. Our results indicate a differential modulation of kelfib metabolism by HePC, suggesting a possible new therapeutic approach for keloid and hypertrophic scars in vivo.

Cell Division↗
PubMed1997

Clinical efficacy and safety comparison of adapalene gel and tretinoin gel in the treatment of acne vulgaris: Europe and U.S. multicenter trials.

BACKGROUND: Adapalene is a new chemical entity that exhibits tretinoin-like activities in the terminal differentiation process. OBJECTIVE: We evaluated a dose range effect of two concentrations of adapalene gel as acne treatment and compared adapalene 0.1% gel with tretinoin 0.025% gel in the treatment of acne patients in two large multicenter studies. METHODS: Multicenter, investigator-masked, parallel group studies including 89 acne patients in the dose range study and 591 patients in the concurrent controlled studies were conducted. RESULTS: Adapalene gel 0.1% was significantly more effective in treating acne lesions than 0.03% adapalene gel. Adapalene gel 0.1% was significantly more effective than 0.025% or tretinoin gel in one study and of the same effectiveness in the other study. Adapalene gel was always better tolerated than tretinoin gel. CONCLUSION: Adapalene 0.1% gel is a safe and effective treatment of acne vulgaris.

Adapalene↗
PubMed1997

Merkel cell carcinoma: report of ten cases with emphasis on clinical course, treatment, and in vitro drug sensitivity.

BACKGROUND: Merkel cell carcinoma (MCC) is an uncommon primary neuroendocrine skin tumor most often seen in the elderly. The clinical course varies. Treatment is controversial and few data on drug sensitivity are available. OBJECTIVE: We evaluated the clinical course and treatment of 10 MCC patients and determined MCC chemosensitivity. METHODS: Clinical records as well as laboratory and histopathologic data from 10 patients with MCC treated in our department were examined. Chemosensitivity to various chemotherapeutic agents and interferons of MCC cells from four patients was determined in a soft agar clonogenic assay. RESULTS: MCC behaved as an aggressive tumor with early and frequent local relapses (4 of 10 patients at a 2.2-month average), regional (4 of 10 patients at 2.5 months), and distant metastases (5 of 10 patients 9.6 months after excision of the primary tumor). In all but one patient, regional metastases preceded distant ones. Metastatic spread was associated with an average survival of 21 months from the initial diagnosis. Long-term survival (53+ and 65+ months) was observed in two women. Wide excision of the primary tumor, alone or combined with adjuvant chemotherapy and radiotherapy, was the most effective treatment. In advanced disease, chemotherapy and radiotherapy were not able to induce long-term remission. In vitro assays for MCC drug sensitivity revealed cisplatin, doxorubicin, and vindesine to be the most active. CONCLUSION: MCC has a poor prognosis in advanced stages; therefore the primary tumor should be aggressively treated. The in vitro clonogenic assay may help to identify the chemosensitivity profile of MCC and to optimize chemotherapy protocols.

Adult↗
PubMed1997

Inhibition of plasma membrane NADH oxidase activity and growth of HeLa cells by natural and synthetic retinoids.

Several retinoids, both natural and synthetic, were evaluated for their ability to modulate NADH oxidase activity of plasma membranes of cultured HeLa cells and the growth of HeLa cells in culture. Both NADH oxidase activity and the growth of cells were inhibited by the naturally-occurring retinoids all trans-retinoic acid (tretinoin) and retinol as well as by the synthetic retinoids, trans-acitretin, 13-cis-acitretin, etretinate and arotonoid ethylester (Ro 13-6298). For all retinoids tested, inhibition of NADH oxidase activity and inhibition of growth were correlated closely. With tretinoin, etretinate and arotonoid ethylester, NADH oxidase activity and cell growth were inhibited in parallel in proportion to the logarithm of retinoid concentration over the range of concentrations 10(-8) to 10(-5) M. Approximately 70% inhibition of both NADH oxidase activity and growth was reached at 10 microM. With retinol, trans-acitretin and 13-cis-acitretin, inhibition of NADH oxidase activity and growth also were correlated but maximum inhibition of both was about 40% at 10 microM. The possibility is suggested that inhibition of the plasma membrane NADH oxidase activity by retinoids may be related to their mechanism of inhibition of growth of HeLa cells in culture.

Animals↗
PubMed1997

L-ascorbic acid inhibits UVA-induced lipid peroxidation and secretion of IL-1alpha and IL-6 in cultured human keratinocytes in vitro.

We investigated the antioxidative effect of L-ascorbic acid on lipid peroxidation and on secretion and mRNA expression of IL-1alpha and IL-6 after UVA irradiation (20 J/cm2) in cultured human keratinocytes. Lipid peroxidation was measured by (i) high performance liquid chromatography with UV detection of malondialdehyde (MDA) at 256 nm and (ii) spectrometric measurement of thiobarbituric acid-reactive substances (TBARS). To evaluate UV-induced cytotoxicity, we assessed cell membrane damage by measuring lactate dehydrogenase (LDH) release. UVA-induced lipid peroxidation in cultured human keratinocytes was inhibited by ascorbic acid in a concentration-dependent manner: MDA protein equivalent was reduced by 47% (10(-6)), compared to keratinocytes not exposed to L-ascorbic acid (p < 0.05), and the TBARS showed a concentration-dependent decrease of 49% (10(-6) M) in L-ascorbic acid-supplemented cultures compared to controls (p < 0.05). LDH release was decreased by 45% in L-ascorbic acid-supplemented keratinocyte cultures, indicating protection against cell death (p < 0.05). L-Ascorbic acid was able to downregulate IL-1alpha mRNA expression in both UVA-irradiated and nonirradiated cells; however, IL-6 mRNA expression remained unaffected. The secretion of these cytokines was reduced nearly to normal in the presence of L-ascorbic acid. These findings indicate a major cell-protective effect of L-ascorbic acid on UVA-induced lipid peroxidation and the secretion of pro-inflammatory cytokines by UVA-irradiated human keratinocytes.

Ascorbic Acid↗
PubMed1997

Symmetric lipomatoses in female patients.

BACKGROUND: Symmetric lipomatoses are characterized by marked symmetric deposition of diffusely distributed fatty tissue. Though relatively common disorders, they are rather rarely reported in the literature, possibly being misdiagnosed as general obesity. While the differential diagnosis of symmetric lipomatosis versus general obesity may not appear difficult in males, it is obviously problematic in females. OBSERVATIONS: We describe the findings in 6 representative female patients with symmetric lipomatoses: 3 with benign (multiple) symmetric lipomatosis and 3 with female zonal obesity. The former disorder was characterized by massive, firm, symmetric fat deposition predominantly around the neck and shoulder girdle and was clearly associated with alcohol abuse and/or liver disease. There were no malignant tumors of the upper airways. In the latter case, fatty tissue had accumulated mainly at the buttocks and thighs but characteristically spared the feet and hands. Tenderness was a common symptom. This disorder showed familial predisposition. Histology in both cases revealed normal fatty tissue which was neither encapsulated nor septally divided. CONCLUSIONS: We suggest that the term 'symmetric lipomatoses' refers to two separate disorders, benign (multiple) symmetric lipomatosis and female zonal obesity.

Adipose Tissue↗
PubMed1997

Epidemiology and socioeconomic impact of skin disease in lupus erythematosus.

The prevalence rates of systemic lupus erythematosus (SLE) may vary within 17-48/100,000 population worldwide. Although population-based epidemiological studies are still missing, the cutaneous variants of lupus erythematosus (LE) are 2-3 times more frequent than SLE itself. The most common age of onset is 20-40 y. Overall, cutaneous LE is regarded as a variant with less severe course and better prognosis. However, CDLE and SCLE last for many years and may lead, like SLE, to severe disability for work and limited life quality; also, a small proportion of patients with cutaneous LE develops SLE during the course of their disease. This implies considerable amount of medical management and costs for the community. Early recognition of cutaneous LE patients at risk to develop SLE and preventive measures against disease triggering factors are important tasks for physicians attending with cutaneous LE patients. It seems that signs of nephropathy, elevated ANA-titers and arthralgias may serve as prognostic predictors for transition into SLE. Characteristic features of cutaneous LE are photosensitivity and female predominance. UV light is a major environmental triggering factor in cutaneous LE. Skin lesions may be induced or preexistent lesions may exacerbate due to UV light in up to 80-90% of all patients. Therefore, socioeconomic counseling of the young patients, for example choice of occupation and sun protection, are essentials in compliant patients. Also, since females are 3-6 times more frequently affected than males, the possibility of hormonal influences including pregnancy and estrogen-containing drugs should be discussed. Risk considerations for females wishing to become pregnant are required, and avoidance of estrogen-containing contraceptives should be recommended.

Adolescent↗
PubMed1997

Current use and future potential role of retinoids in dermatology.

Since their introduction 15 years ago, retinoids have been increasingly used for topical and systemic treatment of psoriasis and other hyperkeratotic and parakeratotic skin disorders, keratotic genodermatoses, severe acne and acne-related dermatoses, and also for therapy and/or chemoprevention of skin cancer and other neoplasia. Oxidative metabolites of vitamin A (retinol) are natural retinoids present at low levels in the peripheral blood. Synthetic retinoids are classified into 3 generations including nonaromatic, monoaromatic and polyaromatic compounds. They are detectable in plasma 30-60 minutes after systemic administration, and reach maximum concentrations 2 to 4 hours later. Elimination half-life is 10 to 20 hours for isotretinoin, 80 to 175 days for etretinate and 2 to 4 days for, trans-acitretin; the latter, however, partially converts into etretinate. Retinoid concentrations in skin are rather low in contrast to subcutaneous fat tissue. Intracellularly, retinoids interact with cytosolic proteins and specific nuclear receptors. Two classes of nuclear receptors have been suggested to mediate retinoid activity at the molecular level, RARs and RXRs. The expression of retinoid receptors is tissue specific; skin mainly espresses RAR gamma and RXR alpha. Retinoids affect epidermal cell growth and differentiation as well as sebaceous gland activity and exhibit immunomodulatory and anti-inflammatory properties. Current retinoid research targets the development of receptor-selective retinoids for tailoring and/or improving their therapeutic profile. Currently, tretinoin is used systemically for acute promyelocytic leukaemia, etretinate and acitretin for psoriasis and related disorders, as well as other disorders of keratinisation and isotretinoin for seborrhoea, severe acne, rosacea and acneiform dermatoses. Systemic retinoids are also applied for chemoprevention of epithelial skin cancer and cutaneous T cell lymphoma. The major adverse effect of retinoids is teratogenicity; all other adverse effects are dose-dependent and controllable. Contraception is, therefore, essential during retinoid treatment in women of child-bearing age. Clinical monitoring requires physical examination for adverse effects every 3 to 4 weeks and proper laboratory investigations, also including analysis of retinoid bioavailability in selected cases. Topical retinoids are rapidly developing at present and seem promising for the future; their clinical application includes acne, aging, photodamage, precanceroses, skin cancer and disorders of skin pigmentation. The development of receptor-specific retinoids for topical treatment of psoriasis and/or acne may lead to interesting new compounds based on our current concepts of retinoid function.

Forecasting↗
PubMed1996

Evidence for phosphorylation of CTP:phosphocholine cytidylyltransferase by multiple proline-directed protein kinases.

Reversible phosphorylation of CTP:phosphocholine cytidylyltransferase, the rate-limiting enzyme of phosphatidylcholine biosynthesis, is thought to play a role in regulating its activity. In the present study, the hypothesis that proline-directed kinases play a major role in phosphorylating cytidylyltransferase is substantiated using a c-Ha-ras-transfected clone of the human keratinocyte cell line HaCaT. Cellular extracts from epidermal growth factor-stimulated HaCaT cells and from ras-transfected HaCaT cells phosphorylated cytidylyltransferase much stronger as compared with extracts from quiescent HaCaT cells. The tryptic phosphopeptide pattern of cytidylyltransferase phosphorylated by cell-free extracts from ras-transfected HaCaT cells was similar compared with the patterns of cytidylyltransferase phosphorylated by p44mpkmitogen-activated protein kinase and p34cdc2 kinase in vitro, whereas in the case of casein kinase II the pattern was different. Furthermore, in c-Ha-ras-transfected HaCaT cells the in vivo phosphorylation state of cytidylyltransferase was 2-fold higher as compared with untransfected HaCaT cells. This higher phosphorylation of cytidylyltransferase in the ras-transfected clone was reduced to a level below the phosphorylation of cytidylyltransferase in untransfected cells, using olomoucine, a specific inhibitor of proline-directed kinases. The reduced phosphorylation of cytidylyltransferase in olomoucine-treated cells correlated with an enhanced stimulation of enzyme activity by oleic acid.

CDC2 Protein Kinase↗
PubMed1996

The antitumor phospholipid analog, hexadecylphosphocholine, activates cellular phospholipase D.

Hexadecylphosphocholine (HePC), a glycerol-free phospholipid analog, belongs to a new class of drugs that demonstrate selective anticancer activity. The mechanisms underlying the anticancer activity are unclear. To investigate possible signal transduction relationships we examined the influence of HePC on cellular phospholipid metabolism. When HePC was added to cultured human breast fibroblasts (CCD-986-SK cells) that had been radiolabeled with fatty acid, phosphatidylethanol (PEt, the transphosphatidylation product of phospholipase D (PLD)) formation was stimulated as early as 5 min after addition. In cells labeled with [3H]choline, HePC treatment caused release of choline-containing metabolites to the culture medium, concurrent with PEt formation. HePC also elicited formation of diacylglycerol (DG) which, after 30 min increased 3.5-fold over control. As little is known regarding HePC and PLD, attention was directed towards studies on PC metabolism by PLD. PEt formation was shown to be optimal at 20-50 microM HePC, and structure-activity studies showed HePC to be more potent than either lyso-phosphatidylcholine or 1-hexadecyl-2-O-methyl-rac-glycero-3-phosphocholine for PLD activation. PLD activity induced by HePC was totally inhibited by cellular pretreatment with phorbol dibutyrate, and 59% diminished by pretreatment of cells with staurosporine, a protein kinase C (PKC) inhibitor. Our results demonstrate for the first time that HePC activates PLD, and suggest that PKC participates in this response. The relationship of PLD to the anticancer properties of HePC may be clinically relevant to drug actions.

Antineoplastic Agents↗
PubMed1996

c-Ha-ras oncogene expression increases choline uptake, CTP: phosphocholine cytidylyltransferase activity and phosphatidylcholine biosynthesis in the immortalized human keratinocyte cell line HaCaT.

The effect of c-Ha-ras transfection on phosphatidylcholine biosynthesis of the keratinocyte cell line HaCaT was investigated. It was shown that ras-transfection caused a 3-fold increase of choline incorporation into phosphatidylcholine. By investigating the mechanisms underlying this phenomenon, two targets were obtained. First, the choline uptake was elevated by 2-fold in ras-transfected HaCaT cells as compared with untransfected HaCaT cells, and second, the activity of the rate-limiting enzyme of phosphatidylcholine biosynthesis, CTP:phosphocholine cytidylyltransferase, was increased by 43%. Stimulation of HaCaT cells and ras-transfected HaCaT cells with oleate revealed that the increased activity of cytidylyltransferase might be due to a higher level of enzyme. In these experiments, a 75% increase of the specific activity of fully stimulated, membrane-bound cytidylyltransferase was found in ras-transfected HaCaT cells. Choline kinase which has been previously described as a target of ras-transfection in fibroblasts was unaffected.

Cell Division↗
PubMed1996

The vitamin D3 analogue, calcipotriol, induces sphingomyelin hydrolysis in human keratinocytes.

The possible role of sphingomyelin cycle for the regulation of cell proliferation was investigated in human keratinocytes. The time-dependent breakdown of sphingomyelin was observed in the immortalized human keratinocyte cell line HaCaT as well as in primary human keratinocytes thereby providing evidence that the sphingomyelin cycle might be of importance in the epidermis. Peak levels of 20-30% sphingomyelin hydrolysis were measured 3 h after treatment of the cells with 1 alpha,25-dihydroxyvitamin D3 or with the vitamin D3 analogue, calcipotriol. The decrease of sphingomyelin upon addition of vitamin D3 or calcipotriol was accompanied by an approximately 70% increase of ceramide in the cells. The effects of vitamin D3 and calcipotriol on sphingomyelin breakdown were paralleled by their antiproliferative potency. Furthermore, the cell-permeable ceramide, N-acetylsphingosine, and natural ceramide inhibited cell proliferation of human keratinocytes. The results presented suggest that induction of the sphingomyelin cycle represents one mechanism mediating the therapeutic effect of calcipotriol in treatment of psoriasis.

Calcitriol↗