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Biomedical subjects

S Seidenari

Publications and source records attributed to S Seidenari.

At least 55 records · Page 3Linked to original sources
PubMed1999

Variations in facial skin thickness and echogenicity with site and age.

The characteristic pattern of reflectivity of facial skin, as evaluated by ultrasound, has not previously been described quantitatively. The aim of this study was to evaluate site- and age-dependent variations in skin thickness and echogenicity of facial skin. A total of 40 women, in different age groups, were studied at 12 different facial skin sites. Echographic images were recorded with a 20 MHz B-Scanner and processed by dedicated software. Skin thickness measurements showed significantly higher values on the lower part of the face, whereas skin echogenicity was higher on the upper part of the face. In elderly subjects, an increase in facial skin thickness and overall echogenicity was observed compared with the younger subjects at all assessed skin areas, except the infraorbital regions. Moreover, modifications of skin echogenicity according to age, consisting in the appearance of a subepidermal band and an enhancement of the lower dermis' reflectivity, were observable at most facial skin sites.

Adult↗
PubMed1999

Digital videomicroscopy and image analysis with automatic classification for detection of thin melanomas.

The aim of our investigation was to evaluate the usefulness of a system composed of a digital videomicroscope equipped with a dedicated program for the quantitative characterization of various parameters of the clinically significant features of pigmented skin lesion (PSL) images, forming the basis for automatic differentiation of naevi and thin melanomas. In total 424 naevi and 37 melanomas (including 23 thinner than 0.75 mm) were considered. All the digital images were acquired, framed and analysed using the DBDermo-MIPS program (Biomedical Engineering Dell'Eva-Burroni), which calculates different parameters related to the geometry, the colour distribution and the internal pattern of the lesion. We also assessed the efficacy of an automatic classifier, trained for 100% sensitivity using a subset of PSL images (59 naevi and 19 melanomas), on a test set including 365 naevi and 18 melanomas thinner than 0.75 mm. Significant differences between values from benign and malignant PSLs were observed for most of the numerical parameters. Values from the training set underwent elaboration by means of multivariate discriminant analysis, enabling the identification of variables that are important for distinguishing between the groups in order to develop a procedure for predicting group membership for new cases (test set) in which group membership is undetermined. Going on the training set data, a threshold score was established, enabling each melanoma to be attributed to the right group. When the same threshold value was employed for discriminating between benign and malignant lesions in the test set, all the melanomas were correctly classified, whereas 30 out of the 365 benign lesions were attributed to the wrong group. Thus the specificity of the system reached 92%, whereas the sensitivity was 100%. Our data suggest that elaboration of videomicroscopic images by means of dedicated software improves diagnostic accuracy for thin melanoma. Since elaboration of an image requires only 60s using our system, all the parameter data are available in real time and can be immediately examined by the classifier, providing an instant aid to clinical diagnosis.

Databases, Factual↗
PubMed1999

In vitro testing of tensides employing monolayer cultures: a comparison with results of patch tests on human volunteers.

Evaluation of the irritant potential of new products or ingredients prior to human testing is generally performed in vivo on animals. However, according to the 6th amendment and following updates of the European Community directive on cosmetic products (93/35/EEC), animal testing will be banned when suitable substitutes will be available. To know whether in vitro tests for assessment of skin irritancy provide results approaching human conditions, comparisons have to be made between data deriving from in vitro tests and skin response in humans. The aim of our study was to assess the validity of the monolayer culture system of normal human keratinocytes as a model for the evaluation of the irritant effects of detergents, by comparing in vitro cell culture data to in vivo acute skin irritancy effects of cocamidopropyl betaine (CAPB), an amphoteric compound, Tween 20 (TW20) (polysorbate 20) and Tween 80 (TW80) (polysorbate 80), representing nonionic compounds, applied to the skin of 24 healthy volunteers at a concentration similar to that employed in commercial products. As parameters for cytotoxicity, cell proliferation, cell membrane integrity and cell metabolism were assessed by cell counts, thymidine incorporation, MTT conversion, and Neutral Red uptake. In order to increase the sensitivity of the in vivo evaluation, bioengineering methods for assessment of the effects of test products on the skin were employed. Whereas all 4 in vitro methods ranked the tensides according to their toxicity in the following order: CAPB>SLS>TW20>TW80, both in vivo methods agreed in identifying SLS as the most irritating substance. Moreover, as compared with the irritation potential on human skin, all 4 in vitro tests overestimated the toxicity of CAPB. This suggests that the keratinocyte monolayer cell culture technique cannot directly replace in vivo methods, and that data obtained by this method should be interpreted cautiously.

Adolescent↗
PubMed1998

Digital videomicroscopy improves diagnostic accuracy for melanoma.

BACKGROUND: To enhance the clinical evaluation of pigmented skin lesions (PSL), examination of PSL at a high magnification and computer-aided diagnosis have been introduced. Besides surface microscopes, "videomicroscopes" that are provided with polarized light are commercially available. Images recorded in the polarizing mode are comparable with those obtained after application of a drop of oil and a glass slide. OBJECTIVE: The purpose of this study was to evaluate the usefulness of a digital videomicroscope equipped with a dedicated program for the diagnosis of melanocytic PSL by assessing the digital features referring to benign and malignant PSL images and by comparing the clinical assessment performed on 20-fold magnified images to computer diagnosis that were provided by the discriminant analysis calculation carried out on the numeric values describing the images. METHODS: Nine hundred seventeen melanocytic PSL images, corresponding to 852 nevi and 65 melanomas, were considered. For microscopic examination, a 10- (39 cases), 20-(501 cases), or 50-fold magnification (377 cases) was chosen according to the size of the lesion, enabling the whole lesion to be seen on the monitor. All digital images were framed and analyzed with software that calculates different features related to the geometry, color distribution, and internal pattern of the lesion. Features referring to benign and malignant PSL were compared. Moreover, 90 PSL images recorded by a x20 magnification, corresponding to 59 benign PSL and 31 malignant melanomas, were evaluated by 2 observers, 1 observer experienced in videomicroscopy and 1 observer, an untrained dermatologist. Sensitivity and specificity were estimated for observer assessment and computer diagnosis. RESULTS: Significant differences between values referring to benign and malignant PSL were observed for most numeric features. Sensitivity was higher for the computer assessment and lower for the inexperienced observer, whereas specificity was the same for the computer and the trained observer. CONCLUSION: Numeric features referring to benign PSL significantly differ from those of malignant PSL images. Elaboration of videomicroscopic images by means of a dedicated program improves diagnostic accuracy over the simple examination of pigmented skin lesions by means of magnifying and polarizing systems.

Algorithms↗
PubMed1998

The quantification of patch test responses: a comparison between echographic and colorimetric methods.

Patch testing is widely used both for clinical and experimental purposes. Although the clinical grading employed routinely is of practical value, the lack of objectivity makes it unsuitable for research purposes and dose-response analysis studies. Instrumental measuring techniques have been applied to patch test evaluation, because they enable objective quantification of different biophysical aspects of the inflammatory reaction by means of a continuous assessment scale, providing data suitable for statistical analysis. In order to compare the colorimetric and echographic methods for the evaluation of reactions of different intensity, we performed patch tests with 5% nickel sulfate on the flexor aspect of the forearm in 120 nickel-sensitive patients. Clinical and instrumental measurements were performed at 72 h. Numerical values corresponding to instrumental measurements were compared to the positivity degree, as assessed clinically. Whereas echographic parameters, expressing the intensity of oedema and inflammatory infiltration, enabled a distinction between +, +2 and +3 reactions, colorimetric a* values, describing erythema, failed to distinguish between +2 and +3 reactions. Thus, the use of ultrasound is advisable for the quantification of skin reactions of great intensity, whereas the colorimetric method could be usefully employed for dose-response studies assessing minimal eliciting concentrations of allergens, and for the evaluation of clinically undetectable reactions.

Adult↗
PubMed1998

Ceramide and cholesterol composition of the skin of patients with atopic dermatitis.

Atopic dermatitis skin tends to be easily irritated and appears dry. These clinical peculiarities correspond to impaired barrier function and to increased transepidermal water loss (TEWL) values. A few studies suggest that a reduced amount of total ceramides (especially of ceramide 1) is responsible for functional abnormalities of the skin of atopic dermatitis patients. The aim of this study was to analyze the relationship between epidermal lipids and barrier impairment in the skin of patients with atopic dermatitis. The quantity of ceramides, cholesterol sulphate and free cholesterol of 47 patients with atopic dermatitis and 20 age- and sex-matched healthy subjects was assessed by cyanoacrylate stripping and thin layer chromatography. Capacitance and TEWL were recorded at the same site of the lipid sample. In patients with atopic dermatitis, the levels of ceramide 1 and 3 were significantly lower and values of cholesterol significantly higher with respect to healthy subjects. Moreover, the CER/CH ratio was significantly lower with respect to normal skin. Patients with active signs of eczema also had higher TEWL values and lower capacitance values. By contrast, patients with no active signs of atopic dermatitis had a normal barrier function and intermediate values of ceramides and cholesterols, when compared to patients with atopic dermatitis with active lesions and normal subjects. The quantity of ceramide 3 was significantly correlated with TEWL impairment. These findings suggest that a decrease in ceramides in the stratum corneum is involved in barrier impairment in atopic dermatitis skin. Our data confirm those of other authors and support the view that impaired metabolism of ceramides may be the cause of dry skin and impaired barrier function in atopic dermatitis.

Adolescent↗
PubMed1998

Baseline biophysical parameters in subjects with sensitive skin.

Sensitive skin has been described as a skin type showing higher reactivity than normal skin and developing exaggerated reactions when exposed to external factors. The stinging test, performed by applying lactic acid to the nasolabial fold and evaluating the intensity of subjective symptoms, is widely accepted as a marker of sensitivity and employed for the selection of subjects experiencing invisible cutaneous irritation. However, this test is based on self-perceived assessment and lacks objectivity. In order to contribute to the finding of objective descriptors, we assessed baseline biophysical parameters in subjects with sensitive skin by means of transepidermal water loss (TEWL), capacitance, pH, sebum and skin colour measurements, and compared the data with those obtained in normal subjects, also correlating the results with those of clinical assessments and functional tests. Subjects with sensitive skin showed a trend towards higher scores at all assessment times both for the stinging and the washing test. The skin of sensitive subjects was described as less supple, less hydrated and more erythematous and telangiectatic with respect to the skin of normal subjects. A trend towards an increase in TEWL, pH and colorimetric a* values, and a decrease in capacitance, sebum and colorimetric L* values on the face of subjects with sensitive skin was observable. However, significances were only present for capacitance and a* values. Thus, alterations of baseline capacitance values indicate the tendency to barrier impairment and support the view that skin hyperreactivity to water-soluble irritants is induced by a greater amount of irritants absorbed, whereas the increase in the erythema parameter shows that cutaneous vascular hyperreactivity in subjects with sensitive skin also corresponds to baseline vasodilation.

Adult↗
PubMed1998

Patch testing with nickel sulfate: comparison between 2 nickel sulfate preparations and 2 different test sites on the back.

Among patients routinely undergoing patch testing for suspected allergic contact dermatitis (ACD), nickel is the most frequently sensitizing hapten, with a clear predominance in the female population. However, some patients who report the appearance of dermatitis upon exposure to metal objects show negative patch test results to a nickel sulfate 5% pet. application. In some cases, a positive response to nickel can be observed simply by repeating the patch test. The objective of our study was to assess if, during routine patch testing, positive responses to nickel sulfate are missed owing to contingent problems, referring to application site, patch test execution or variations in skin reactivity. To this end, we applied 2 different patch test materials containing nickel sulfate 5% pet. to 3040 consecutive patients, undergoing patch testing for suspected allergic contact dermatitis, during the same session. The rôle of the test site was also investigated by applying the preparation on 2 different sites of the back in 30 patients. Of the whole, 612 patients (20%) showed positive patch test responses. The 2 nickel materials were almost equivalent: 78% of nickel-sensitive patients had positive reactions to both, whereas 11% showed a positive response to 1 preparation alone. No variations in patch test responses in relation to application site were observed. Our data show that false-negative patch test responses to nickel are frequent. The use of 2 different preparations during the same patch test session increases the response rate by 10%.

Adolescent↗
PubMed1997

Cross-sensitizations between azo dyes and para-amino compound. A study of 236 azo-dye-sensitive subjects.

Combined sensitizations to different azo dyes, probably based both on true cross-sensitization and on simultaneous positive reactions, have frequently been described. However, since azo dyes are included in the standard series in a minority of countries, the case studies considered comprise, with few exceptions, a small number of subjects. The aim of our study was to investigate cross-reactions between different azo dyes and para-amino compounds in azo-dye-sensitive subjects, to study the clinical aspects of azo dye dermatitis, to assess the relevance of sensitization to azo dyes, and to relate the pattern of cross-sensitizations to the chemical structure of the different dyes. Out of 6203 consecutively tested patients, 236 were sensitized to at least 1 of 6 azo compounds employed as textile dyes, included in our standard series. 107 subjects reacted to Disperse Orange 3 (DO3), 104 to Disperse Blue 124 (DB124), 76 to p-aminoazobenzene (PAB), 67 to Disperse Red 1 (DR1), 42 to Disperse Yellow 3 (DY3), and 31 to p-dimethylaminoazobenzene (PDAAB). Co-sensitizations to para-phenylenediamine were present in most subjects sensitized to DO3 (66%) and PAAB (75%), in 27% and 36% of DR1 and DY3-sensitive subjects, and only in 16% of subjects sensitized to DB124. Apart from the hands and the face, the neck and the axillae were the most frequently involved skin sites. Whereas the involvement of flexural areas was mainly connected with sensitization to DB124, in patients with hand dermatitis and in those working as hairdressers, sensitization to DO3 and PAAB was more frequent. Moreover, in the former patient group, a history of textile dye allergy was most frequently obtained. Out of 33 patients tested with an additional textile dye series, only 5 subjects reacted to anthraquinone dyes. Cross-sensitizations between azo dyes and para-amino compounds can partially be explained on the basis of structural affinities.

Azo Compounds↗
PubMed1997

Parallel intraindividual evaluation of the vasoconstrictory action and the anti-allergic activity of topical corticosteroids.

The human skin blanching assay is a well established method for ranking the efficacy of corticosteroids after epicutaneous application. Vasoconstriction is a pharmacological activity, which correlates well with the clinical efficacy, the intensity of skin blanching after a single application under occlusion corresponding, generally, to the clinical efficacy after repeated application without occlusion. However, in studies dealing with the comparison between the vasoconstriction assay and the evaluation of the clinical effects on inflammatory skin diseases, some exceptions to this correlation have been reported. Therefore, in a pre-clinical phase, it would be useful to combine the blanching assay with at least one anti-inflammatory assay. In the present study the blanching assay and the allergic contact dermatitis inhibition test were performed in parallel, in order to compare the two testing procedures in the same group of subjects, utilizing standardized study designs supported by objective means of evaluation. Three commercial preparations of corticosteroids containing clobetasol propionate (CP), clobetasone butyrate (CB) and hydrocortisone acetate (HA), respectively, were employed both to treat nickel-induced positive patch test responses on the volar forearms, and to perform a vasoconstrictor assay on normal forearm skin in 16 nickel-sensitized healthy volunteers. For evaluating skin blanching, we employed colorimetric measurements, whereas for the quantitative determination of the inhibition of the intensity of allergic patch test reactions, 20 MHz B-scanning supported by image analysis was used. Both colorimetric and echogenicity values enabled us to distinguish between the three corticosteroids (at the 17 h evaluation and the 64 h assessment, respectively). A fair correlation was noted between colorimetric and echogenicity values. Both testing procedures ranked the three corticosteroids in the expected order. Corticosteroid preparations should be compared using methods which allow different effects to be simultaneously monitored, without involving a high number of patients. We are proposing this double procedure for the parallel intraindividual evaluation of the vasoconstrictory action and the anti-allergic activity of topical steroids.

Administration, Topical↗
PubMed1997

Inhibition of elicitation of contact dermatitis in humans by mometasone furoate: evaluation by means of 20-MHz B scanning associated with image analysis.

BACKGROUND: Mometasone furoate (MF) is a new strongly lipophilic steroid which has an anti-inflammatory effect as evaluated by in vivo and in vitro studies. OBJECTIVE: The objective of the present study was to investigate the degree of inhibition of experimental allergic contact dermatitis induced by the treatment with MF. METHODS: The therapeutic effect was evaluated by an echographic method associated with image analysis. MF activity was compared to that of hydrocortisone acetate 0.5% (Cortaid Cream, Lachifarma), clobetasone butyrate 0.05% (Eumovate Cream, Glaxo) and clobetasol propionate 0.05% (Clobesol Cream, Glaxo), classified respectively as weak, moderately potent and very potent steroids. RESULTS: The different corticosteroid formulations employed for inhibiting experimentally induced contact dermatitis reflect the expected rank order of efficacy. CONCLUSION: MF behaves like clobetasol butyrate ranking as a moderately potent corticosteroid.

Administration, Topical↗
PubMed1996

Skin reactivity to sodium lauryl sulfate in patients with respiratory atopy.

BACKGROUND: No literature data are available on the skin reactivity of patients with respiratory atopy alone. OBJECTIVE: Our purpose was to assess skin reactivity to detergents in patients with allergic asthma, rhinitis, or both. METHODS: The skin of the volar aspect of the forearm of 19 subjects with allergic asthma or rhinitis (or both) was challenged with a single exposure to 0.5% sodium lauryl sulfate. The skin response was evaluated by transepidermal water loss (TEWL), capacitance, and echogenicity measurements. Results were compared with those obtained in 19 patients with atopic dermatitis (AD) and 20 healthy subjects. RESULTS: In patients with AD preexposure TEWL values were higher than in healthy subjects, whereas capacitance values were lower. In this patient group, postexposure TEWL, capacitance, and echogenicity values showed more pronounced variations than in healthy subjects. Conversely, in patients with allergic asthma or rhinitis (or both), both baseline and postexposure TEWL, capacitance, and echogenicity values were similar to those in healthy subjects. CONCLUSION: Patients with respiratory atopy without AD do not have the functional abnormalities characteristic of skin affected by AD, either under baseline conditions or after exposure to sodium lauryl sulfate.

Adult↗
PubMed1996

Pre-treatment of nickel test areas with sodium lauryl sulfate detects nickel sensitivity in subjects reacting negatively to routinely performed patch tests.

A fair % of patients with a clinical history of nickel allergy show negative patch test results. To improve the response rate to NiSO4 5% pet. patch tests, a testing procedure utilizing pre-treatment of the test area by a 24-h application of sodium lauryl sulfate (SLS) was introduced. 46 women with a clinical history of nickel sensitivity, who exhibited negative reactions to nickel sulfate 5% pet. patch tests, were studied. Patients underwent 6 patch tests on adjacent sites on the volar surface of the forearms. 4 patch tests were performed with a 72-h application of 40 mg nickel sulfate 5% pet. While 1 of these patch tests served as control, 3 test areas underwent 24-h pre-treatment with 40 microliters SLS, 1 with 0.1% and 2 with 0.5% solution. To evaluate differences in the reactivity to SLS plus nickel sulfate related to the site on the forearm, 0.5% SLS pre-treatment was performed both on a proximal and on a distal test site. At the 72-h evaluation, 19 subjects out of 46 showed positive reactions to nickel sulfate 5% pet. at skin sites pre-treated with 0.1% SLS, whereas 23 patients reacted positively at 0.5% SLS pre-treated areas. Echographic values of skin thickness and of hypo-echogenic dermal areas at positive pre-treated nickel test areas were higher than at control test areas, confirming the clinical evidence of an increased response to NiSO4 after SLS pre-treatment. The inflammatory reaction, as evaluated clinically and echographically, was much higher at distal skin areas (0.1% SLS and distal 0.5% SLS) than at proximal 0.5% SLS ones.

Adult↗
PubMed1996

Sensitization to reactive textile dyes in patients with contact dermatitis.

Reactive dyes are used especially for colouring natural fibres (cotton, silk and wool) that are widely used in Western countries, particularly Italy, in the production of clothes. The aim of our study was to investigate sensitization to the most commonly used reactive textile dyes in patients undergoing patch tests, and to assess the clinical relevance of contact sensitization to these dyes. 1813 consecutive patients underwent patch tests with the GIRDCA standard series and an additional textile series of 12 reactive dyes. 18 of these patients were sensitized to reactive dyes (0.99%) (4 only to reactive dyes). The dyes most frequently responsible for positive patch tests were Red Cibacron CR and Violet Remazol 5R (respectively, 8 and 5 positivities). In 5 cases only was a history of intolerance to particular garments given; of 4 patch tests performed with pieces of garment, 2 were positive. In 1 occupationally-exposed patient, airborne contact dermatitis was suspected. Owing to the lack of up-to-date patch test series, some cases of allergic contact dermatitis from textile dyes are probably misdiagnosed: new colouring agents are continuously introduced to the market, so that a close relationship with textile industry is necessary to improve our diagnostic tools.

Adolescent↗
PubMed1996

Ultrasound description and quantification of irritant reactions induced by dithranol at different concentrations. A comparison with visual assessment and colorimetric measurements.

Dithranol (D) is used as a therapeutic topical agent to treat psoriasis, although it produces inflammation and staining of skin and clothing. D-induced irritation has been evaluated by visual scoring and by bioengineering techniques, evidencing modifications of the inflammatory parameters, but no alterations of the skin barrier. The aim of our study was to evaluate the irritant reactions induced by D using ultrasound, and to compare the B-scanning data with visual assessments and colorimetric measurements. 13 healthy women underwent 2, 3-h patch tests with, respectively, 0.02% and 0.1% D in white petrolatum and 1 24-h patch test with 2% sodium lauryl sulfate (SLS). For assessing skin reactions, clinical judgement, colorimetry and echography were employed. Echographic images were evaluated by skin thickness measurements and segmentation procedures, using an 0-30 interval, marking the hyporeflecting areas in the dermis, and a 201-255 interval, assessing the hyperreflecting components of the image (both epidermal and dermal). In all subjects, D produced uniform reactions, the intensity varying according to concentration. Both echographic parameters of inflammation (skin thickness and 0-30 areas) showed an increase at all times of assessment. The 201-255D/0-30 pixel ratio, describing the distribution of dermal edema, indicated that strong inflammatory reactions, such as those caused by the application of 0.1% D, are accompanied by edema in the lower portion of the dermis. Finally, in contrast to SLS reactions, where a 24-h reduction in epidermal reflectivity was observable, D reactions appeared with an accentuation of the 201-255 epidermal band at 24-96-h examinations.

Administration, Topical↗