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Biomedical subjects

S Seidenari

Publications and source records attributed to S Seidenari.

At least 37 records · Page 2Linked to original sources
PubMed2003

Routine patch testing with frullanolide mix: an European Environmental and Contact Dermatitis Research Group multicentre study.

Contact sensitivity to plants containing 1 or more sesquiterpene lactones (SLs) is difficult to diagnose. The mixture of SLs (SL mix) has been shown to detect only about 60% of sensitized individuals. In order to improve the diagnosis of sensitization to plants containing SLs, we have tested a mixture of frullanolides contained in Frullania dilatata and Frullania tamarisci at 3 different concentrations (0.01%, 0.033% and 0.1% in petrolatum). 8605 consecutive eczema patients in 1 North American and 15 European dermatology departments were tested with this mix, and 0.35% of positive cases to the different concentrations were found. Routine use of this mix permitted detection of only a small percentage of extra cases and did not improve the SL mix score. The frullanolide mix should therefore be restricted to investigations in particular geographical zones and/or in particular occupations.

Allergens↗
PubMed2003

Computer description of colours in dermoscopic melanocytic lesion images reproducing clinical assessment.

BACKGROUND: The assessment of colours is essential for the diagnosis of malignant melanoma (MM), both for pattern analysis on dermoscopic images, and when employing semiquantitative methods. OBJECTIVES: To develop a computer program for colour assessment in MM images mimicking the human perception of lesion colours, and to compare the automatic colour evaluation with one performed by human observers. METHODS: A colour palette comprising six colour groups (black, dark brown, light brown, blue-grey, red and white) was created by selecting single colour components inside melanocytic lesion images acquired by means of a digital videomicroscope, and was implemented in the image analysis program. Subsequently, colours were assessed by the computer program on 331 melanocytic lesion images composing our image database, and the results were compared with the evaluation of lesion colours performed by the clinician. RESULTS: The black, white and blue-grey colours were more frequently found in MMs than in naevi, both by the clinicians and by the computer. In MM images we observed 4.27 +/- 1.14 colours (mean + or - SD) per lesion, as opposed to 3.22 +/- 0.68 in naevi. The correlation between clinical and computer evaluation of the colours was very good, with a value of 0.781 for overall assessment. CONCLUSIONS: This innovative method for automatic colour evaluation, reproducing clinical assessment of melanocytic lesion colours, may provide numerical parameters to be employed for computer-aided diagnosis of MM.

Color↗
PubMed2002

Ultraviolet B radiation induces activation of neutral and acidic sphingomyelinases and ceramide generation in cultured normal human keratinocytes.

The sphingomyelin pathway is an ubiquitous, evolutionary conserved signaling system which transduces an extracellular signal into the cell. During the past few years increasing evidence has shown that the sphingolipid ceramide may play a role as a second messenger in intracellular signal transduction. The ceramide generation via sphingomyelinase (SMase) is followed by three major cellular responses: cell growth arrest, induction of cell differentiation and/or induction of programmed cell death or apoptosis. The aim of this study is to investigate whether activation of SMases and generation of ceramide can be induced by UVB radiation in normal human keratinocytes. The present data show that exposure to UVB radiation results in rapid generation of ceramide. The ceramide accumulation starts 15 min after UV exposure and progressively increases up to 24 h. In vitro measurement of SMase activity following exposure to UVB evidences an activation of both neutral and acidic SMases. Moreover, UVB induces apoptosis in normal human keratinocytes as shown by TUNEL technique and FACS analysis. These data indicate that UVB induced ceramide generation and activation of both neutral and acidic SMases, suggesting that sphingolipids metabolism may be involved in the UVB signaling pathway.

Apoptosis↗
PubMed2002

Monitoring levels of preservative sensitivity in Europe. A 10-year overview (1991-2000).

A 10-year multicentre analysis of the frequency of sensitivity to common preservatives collected in 16 centres in 11 countries has shown stable but persisting high levels of sensitivity to formaldehyde and 5-chloro-2-methyl-4-isothiazolin-3-one + 2-methyl-4-isothiazolin-3-one (MCI/MI). It has also revealed a significant increase in the level of reactivity to methyldibromoglutaronitrile (MDBGN) from 0.7% in 1991 to 3.5% in 2000. The current high level of sensitivity to MDBGN requires an urgent safety re-evaluation and risk assessment update along with consideration of immediate lowering of use concentrations, especially in leave-on products.

Allergens↗
PubMed2002

Sensitization to disperse dyes in a patch test population over a five-year period.

BACKGROUND: In spite of sporadic data pointing at the role of textile dyes as important contact allergens, only few studies have addressed the issue of the frequency of sensitization to textile dyes in populations of consecutive patients. OBJECTIVE: The purpose of this study was to evaluate the prevalence of sensitization to disperse dyes, to investigate cross reactivity between azo dyes and para-amino compounds, to describe azo-dye-positive patients, and to study the correlation between clinical aspects and sensitization to different disperse dyes. METHODS: From January 1996 to December 2000, 6,478 consecutive patients were tested with 7 textile dyes: Disperse Blue 124, Disperse Blue 106, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3 (DO3), para-aminoazobenzene (PAAB), and para-dimethylaminoazobenzene (PDAAB). RESULTS: Of the above, 437 patients were allergic. The most common sensitizers were Disperse Blue (DB) dyes and Disperse Orange 3. Both the clinical aspect and the localization of the lesions were unusual in a fair percentage of cases, especially in DB-positive subjects. Involvement of skin folds was observed in 27% of disperse dye-positive patients, mainly comprising DB-sensitive women. Cross-reactivity between azo-dyes and paraphenylenediamine (PPD) was frequent in DO3-, PAAB-, and PDAAB-positive subjects, but not in DB-allergic ones. Moreover, cross reactions between DB106 and DB124 were observed in 59% of DB106- and/or DB124-positive patients. CONCLUSIONS: The frequency of disperse dye allergy is higher than generally estimated. Further studies, using routine diagnostic testing with disperse dyes, are needed to investigate whether this increasing trend is present outside of Europe.

Adult↗
PubMed2001

Characterization of pseudoxanthoma elasticum-like lesions in the skin of patients with beta-thalassemia.

BACKGROUND: Pseudoxanthoma elasticum (PXE), an inherited disorder of unknown pathogenesis, is characterized by elastic fiber mineralization, collagen fibril alterations, and accumulation of thread material in the extracellular space. PXE-like clinical lesions have been described in patients with beta-thalassemia. OBJECTIVE AND METHODS: Dermal lesions in these two genetic disorders were compared by light and electron microscopy and by immunocytochemistry. RESULTS: In both disorders, elastic fiber polymorphism, fragmentation, and mineralization were structurally identical. Elastic fiber mineralization in beta-thalassemia was associated with vitronectin, bone sialoprotein, and alkaline phosphatase, similar to what was observed in inherited PXE. Furthermore, abnormalities of collagen fibrils and filament aggregates were identical in both disorders. In both inherited and beta-thalassemia-associated PXE, unrelated gene defects seem to induce cell metabolic abnormalities that lead to identical clinical and structural phenotypes. CONCLUSION: Data indicate that patients with beta-thalassemia may undergo important alterations of connective tissues, a better understanding of which may help in preventing clinical complications.

Adult↗
PubMed2001

Water sorption-desorption test and moisture accumulation test for functional assessment of atopic skin in children.

Sorption-desorption and moisture accumulation tests are simple and quick methods for the in vivo functional analysis of stratum corneum hydration kinetics. The aim of this study was to evaluate the hydration dynamics of the uninvolved and affected skin of children with atopic dermatitis and to compare them with the skin of healthy children. The study investigated 45 children. The dynamic tests were performed using the corneometer CM820. Numerical parameters were calculated. With the sorption-desorption test, eczematous skin showed lower water accumulation during the sorption phase, whereas water was released more slowly during the desorption phase. With the moisture accumulation test, increases in water accumulation velocity and in water accumulation were observed in atopic children. Dynamic tests showed that the stratum corneum of unaffected atopic skin was less hydrated but more easily hydratable than normal skin. Conversely, despite a lower absorption capability, eczematous skin showed a greater avidity to retain water. New functional parameters (water-sorption capacity and accumulated water decay) are proposed to describe more precisely the hydration kinetics of eczematous skin.

Body Water↗
PubMed2000

Patch testing with corticosteroid mixes in Europe. A multicentre study of the EECDRG.

This study investigated whether a corticosteroid mix containing tixocortol pivalate, budesonide, and hydrocortisone-17-butyrate could detect contact allergy to corticosteroids. 2 corticosteroid mixes, 1 with a high (mix I) and 1 with a low (mix II) concentration and the 3 individual constituents, each at 2 concentrations, were inserted into the standard series of 16 participating clinics. Tests were read on day (D) 3 or 4. 5432 patients were tested, and 110 (2.0%) had positive reactions to at least 1 of the 8 test preparations. Of the 8 preparations, mix I identified most allergic patients, followed by mix II, budesonide 0.10%, budesonide 0.002%, and tixocortol pivalate, both concentrations (1.0 and 0.10%) tracing the same number. With the mixes, 53.2-59.6% of tixocortol pivalate allergy was missed. 47 patients were allergic to either concentration of tixocortol pivalate, 25% of these only to 1.0% and another 25% only to 0.10%. Testing with mix I and tixocortol pivalate 0.10% picked up 98/110, testing with tixocortol pivalate 1.0% and 0.10% and budesonide 0.10% picked up 105/110. 3379 patients were read on both D3 or D4 as well as on D7. Without a late reading (D7), up to 30% of contact allergy to corticosteroid markers was missed.

Administration, Topical↗
PubMed2000

No increased skin reactivity in subjects with allergic rhinitis during the active phase of the disease.

Data on skin reactivity in patients with respiratory atopy without atopic dermatitis are scarce and controversial. Our purpose was to assess whether skin reactivity in patients with seasonal allergic rhinitis varies according to the phase of the disease and the possible release of inflammatory mediators acting on the skin during the pollen season. The volar forearm skin of eleven patients with seasonal allergic rhinitis without atopic dermatitis was challenged with a single exposure to sodium lauryl sulfate. The skin response was evaluated instrumentally over 72 h by transepidermal water loss, capacitance and echogenicity measurements for the assessment of skin damage and the inflammatory response. Tests were performed in winter and repeated in spring in seasonal allergic rhinitis patients, when they showed respiratory symptoms. Fifteen subjects with atopic dermatitis underwent the same experimental procedure in winter as a control population. Baseline and postexposure values were similar both in winter and in spring in seasonal allergic rhinitis patients. After sodium lauryl sulfate challenge, atopic dermatitis patients showed a higher degree of skin barrier damage and inflammation compared to patients with seasonal allergic rhinitis. These findings suggest that subjects with seasonal allergic rhinitis without atopic dermatitis have normal epidermal barrier function and normal skin reactivity during both the inactive and the active phase of the disease. Inflammatory mediators possibly released by mucous membranes during active allergic rhinitis do not influence skin barrier function.

Adult↗
PubMed2000

Ceramide 2 (N-acetyl sphingosine) is associated with reduction in Bcl-2 protein levels by Western blotting and with apoptosis in cultured human keratinocytes.

BACKGROUND: Ceramides produced by sphingomyelin hydrolysis activate a cycle that is followed by three different major cellular responses: downregulation of cell proliferation, induction of cell differentiation and apoptosis. In the skin, the generation of intracellular ceramide may also provide a link between an extracellular signal and the induction of the apoptosis programme for the elimination of damaged cells. OBJECTIVES: We investigated the effect of ceramides capable of entering cells on cultured keratinocytes. METHODS: Human keratinocytes from neonatal skin were cultured in serum-free medium with or without increasing concentrations of ceramide 2 (CER-2; N-acetyl sphingosine) (5, 10, 20 and 40 micromol L-1). Proliferative effects were studied either by cell counts or by 3H-thymidine incorporation and flow cytometric analysis. Apoptosis was studied by TUNEL staining and Western blot analysis of Bcl-2 protein. RESULTS: Cell counts and DNA synthesis were reduced in a dose-dependent manner following CER-2 treatment. TUNEL staining showed CER-2-induced apoptosis at 48, 72 and 96 h. Western blot analysis showed that CER-2 induces downregulation of Bcl-2 at 24-96 h. CONCLUSIONS: These results demonstrate that CER-2 inhibits cell proliferation and induces apoptosis, possibly via a Bcl-2-dependent mechanism.

Apoptosis↗
PubMed2000

Thickness and echogenicity of the skin in children as assessed by 20-MHz ultrasound.

BACKGROUND: Skin anatomy and physiology undergo modifications throughout the whole lifespan. In children the skin appears with structural characteristics, as evaluated by histology, which differ from those of adults, especially in the first years of life. OBJECTIVE: The aim of our study was to evaluate skin thickness and echogenicity at different sites in children by 20-MHz ultrasound. METHODS: Eight skin sites of 42 children and 30 young adults were studied with a 20-MHz B scanner. Skin thickness and mean echogenicity were evaluated. The echographic images were processed and segmented by a dedicated program: the 0-30 amplitude interval, which marks the hypoechogenic parts of the tissue, and the 201-255 range, highlighting the hyperreflecting areas, have been selected. RESULTS AND CONCLUSION: Whereas skin thickness shows a gradual increase from birth to adulthood, maturation of the skin leads to variations in the intensity of its echogenicity, depending on the different skin areas. Whereas on the face and the trunk it appears lower in adults with respect to children, a gradual increase can be observed on the limbs with growing age. The distribution of skin reflectivity also greatly varies in different phases of life.

Adolescent↗
PubMed1999

Diagnosis of pigmented skin lesions by epiluminescence microscopy: determinants of accuracy improvement in a nationwide training programme for practical dermatologists.

BACKGROUND: The poor accuracy of the clinical examination of pigmented skin lesions (PSLs) is a major limitation of secondary prevention strategies for cutaneous melanoma (CMM). In the last few years, the epiluminescence microscopy (ELM) technique has been used increasingly as an adjunct to clinical examination in the dermatology practice. Although the question of training has emerged as a priority, the diffusion, the effects, and the correlates of educational programmes in ELM have seldom been studied. METHODS: Thirty ELM images of PSLs (11 CMMs, 14 melanocytic nevi (MN), and 5 nonmelanocytic lesions (NMLs) each matched with the corresponding clinical or plain photographic image were independently diagnosed before and after a one-day workshop by 83 Italian dermatologists participating in a nationwide educational programme on ELM. The original histology diagnosis was assumed as a gold standard. The overall effect of training on a set of accuracy measures by PSL type was evaluated. The association of the professional sector (public/private), number of years of general experience in dermatology (1-10/>10), average weekly number of PSLs seen (< or =10/11-20/>20), routine use of ELM (no/yes), and area of residence (northern/southern Italy) with the mean number of PSLs correctly diagnosed before and after training was evaluated with the general factorial analysis of variance. The factors associated with improvement between the two tests were evaluated with the analysis of variance for repeated measures. RESULTS: Compared with pretraining data, the average percentage of exact diagnosis increased significantly for all PSLs (CMMs, 72% vs 55%; MN, 68% vs 64%; NMLs, 67% vs 58%; total lesions combined, 69% vs 60%). Baseline as well as final accuracy were independent from the professional sector and the years of experience but were greater among those subjects who reported >20 PSLs per week compared with the reference group (< or =10 PSLs). The routine use of ELM was associated with a slight advantage in pretraining accuracy. The area of residence was the strongest determinant of baseline as well as final accuracy. The effect of training was independent from all factors studied with the exception of the area of residence with a 13% increase in the frequency of exact diagnosis in northern Italy (from 66-79%) and 6% in southern Italy (from 55-61%). CONCLUSIONS: Though insufficient in absolute terms, a measurable increase in ELM accuracy can be achieved even with intense training sessions of short duration. Medical education to ELM in southern Italy should be a priority.

Clinical Competence↗
PubMed1999

Reduced production of both Th1 and Tc1 lymphocyte subsets in atopic dermatitis (AD).

An imbalance of interferon-gamma (IFN-gamma)-bearing CD4+ T (Th1) cells in the pathogenesis of AD is well recognized; however, a possible role in AD for CD8+ T cells secreting Th1-like cytokines (Tc1) has not been properly addressed. In this study, two- and three-colour FACS analysis allowed us to discriminate the Th1 from the Tc1 subset. AD patients had half the number of IFN-gamma-producing circulating T cells (P < 0.005; 13.6 +/- 1.9% (mean +/- s.d.)) compared with normal donors (25.0 +/- 2.4%). Specifically, both Th1 (4.8 +/- 0.7%) and Tc1 (8.1 +/- 1.1%) cells in AD were decreased compared with Th1 (8.8 +/- 0.8%) and Tc1 (15.0 +/- 1.5%) cells in controls. Moreover, at the mRNA level, the ratios of IFN-gamma/IL-4 and IFN-gamma/IL-10 were lower in cells from AD patients compared with controls. In conclusion, the decrease of IFN-gamma-producing T lymphocytes in AD is due to a reduction in both Th1 and Tc1 IFN-gamma-secreting cells; this may not only contribute to the over-production of IgE, but also explain the high incidence of cutaneous infections observed in AD patients.

CD8-Positive T-Lymphocytes↗