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Biomedical subjects

L Andreassi

Publications and source records attributed to L Andreassi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cyclin D1, B and A expression and cell turnover in psoriatic skin lesions before and after cyclosporin treatment.

BACKGROUND: Cyclosporin induces a dramatic reversal to normality in psoriatic lesions, with a reduction of inflammatory infiltrate and epidermal proliferation. It is known that the cell cycle and cell proliferation are regulated by the sequential activation of cyclin-dependent kinase/cyclin complexes. AIM: We evaluated epidermal cell turnover and thickness, as well as the expression of cyclins D1, B and A in psoriatic skin before and after therapy with cyclosporin. METHODS: Epidermal thickness, mitotic and apoptotic indices (MI, AI), as well as the percentages of epidermal cell nuclei positive for Ki-67 and cyclins D1, B and A were calculated. Cytoplasmic positivity to cyclin B was also evaluated. RESULTS: After 6 weeks of therapy, we observed a clinical improvement of the disease and normalization of the epidermis. Epidermal thickness and Ki-67-, cyclins B- and A-positive nuclei percentage were significantly higher before therapy than after (0.52 +/- 0.05 mm vs. 0.21 +/- 0.03 mm, P < 0.001; 19 vs. 2.6, 19 vs. 3, and 12 vs. 1, respectively; P < 0.0005); cytoplasmic positivity to cyclin B was slightly higher before therapy (score 3 vs. 2-3). Cyclin D1 was negative or expressed in a low percentage of nuclei in psoriasis before therapy (0.78), whereas it was always negative after therapy. MI was 0.15 before therapy, whereas mitoses were almost absent afterwards. Apoptoses were undetectable before therapy, whereas a few apoptoses were observed after treatment (AI = 0.4). CONCLUSIONS: Overexpression of cyclins B and A, rather than D1 seems to characterize psoriasis. Their evaluation could provide further insights in understanding the development of this disorder and could be used to verify the efficacy of currently used therapies as well as future ones.

Adult↗
PubMed1999

Digital dermoscopy analysis for the differentiation of atypical nevi and early melanoma: a new quantitative semiology.

OBJECTIVES: To use a digital dermoscopy analyzer with a series of "borderline" pigmentary skin lesions (ie, clinically atypical nevi and early melanoma) to find correlation between the studied variables and to determine their discriminating power with respect to histological diagnosis. DESIGN: A total of 147 pigmentary skin lesions were histologically examined by 3 experienced dermatopathologists and identified as nevi (n = 90) and melanomas (n = 57). The system evaluated 36 variables to be studied as possible discriminant variables, grouped into 4 categories: geometries, colors, textures, and islands of color. SETTING: University medical department. PATIENTS: A sample of patients with excised pigmentary skin lesions (nevi and melanomas). MAIN OUTCOME MEASURES: Sensitivity, specificity, and accuracy of the model for evaluating "borderline" pigmentary skin lesions. RESULTS: After multivariate stepwise discriminant analysis, only 13 variables were selected to compute the canonical discriminant function. CONCLUSION: The present method made it possible to determine which objective variables are important for distinguishing atypical benign pigmentary skin lesions and early melanoma.

Adult↗
PubMed1999

Autosomal dominant aplasia cutis congenita: report of a large Italian family and no hint for candidate chromosomal regions.

We studied a three-generation pedigree in which seven individuals were affected by aplasia cutis congenita, a rare disorder characterized by the congenital absence of the epidermis, dermis and subcutaneous tissue of the vertex or occipital region. Accurate clinical and formal genetic analysis suggested that this family was affected by the autosomal dominant form of the disease, a hereditary condition due to mutations of an unknown gene. To define the map position of this locus, we performed linkage analysis on candidate chromosomes (long arm of chromosomes 1 and 12). Negative lod scores were obtained for all markers analysed and linkage with genes located in these chromosomal regions was excluded.

Chromosome Mapping↗
PubMed1999

A new model for studying differentiation and growth of epidermal cultures on hyaluronan-based carrier.

Here, a three-dimensional model based on fragments of human de-epidermized dermis (DED) is prepared in order to study the performance of a microperforated, hyaluronan-based membrane as a carrier of cultured epidermal cells. Hyaluronic acid is, in fact, considered to be an optimal biomaterial allowing proliferation of both keratinocytes and melanocytes, and it is already used for clinical aims. The carrier with subconfluent human epidermal cultures is positioned onto the DED and kept in culture until a new epidermis is formed. This model system allowed to study the migration and growth of human epidermal cells from the carrier, resembling 'in vivo' re-epithelization.

Adjuvants, Immunologic↗
PubMed1999

Quantitative characterization and study of the relationship between constitutive-facultative skin color and phototype in Caucasians.

In this study constitutive and facultative colorimetric values were quantified to determine the physiologic changes in Caucasian skin color and to define the correlation between skin color and phototype assessed according to the Fitzpatrick method. Our population consisted of 401 subjects ranging in age from 24 to 28 years with similar life styles. Skin color was measured with a Minolta CR-200 colorimeter on the upper medial quarter of the buttock (constitutive color) and on the cheek (facultative color). Advanced multivariate statistical analysis allowed differentiation between constitutive and facultative skin color in relation to the phototype to be quantified. Moreover, Kullback divergence showed that the probability of correctly determining a subject's phototype is high when the variables of constitutive and facultative skin color are considered together. This interesting result makes it possible, in the future, to use colorimetric values of exposed and nonexposed skin, together with determination of Fitzpatrick phototype and of other phenotypic characters, to better predict cutaneous sun reactivity.

Adult↗
PubMed1999

UV-B radiation microphototherapy. An elective treatment for segmental vitiligo.

BACKGROUND: Vitiligo is a common disease of unknown cause that produces disfiguring white patches of depigmentation. Previous studies have suggested the effectiveness of UV-B radiation in generalized vitiligo (GV) therapy, but there was no evidence to support the same role for segmental vitiligo (SV). OBJECTIVE: The purpose of this study was to use UV-B radiation exclusively on vitiligo patches of individuals affected by SV to evaluate the effectiveness of this therapy. SUBJECTS AND METHODS: Eight individuals with SV were treated for 6 months with a new device called BIOSKIN that can produce a focused beam of UV-B (microphoto-therapy) on vitiligo patches only. Photographs of the subjects were taken at the beginning of the therapy and once a month thereafter for 6 months. The response to treatment was estimated in two comparable photographs using planimetry. A control group of eight individuals matched for sex and age was treated with placebo, using the same device but not releasing any kind of detectable light. RESULTS: After 6 months of microphototherapy five subjects of the eight studied achieved normal pigmentation on more than 75% of the treated areas. In particular, three of these were totally repigmented. Two individuals achieved 50-75% pigmentation of the treated areas, and only one showed less than 50% repigmentation. In the control group only one patient showed moderate repigmentation (less than 50%). CONCLUSION: UV-B microphototherapy seems highly effective in restoring pigmentation in patients affected by vitiligo. As no side-effects have been observed, this could represent the treatment of choice in the limited (segmental) forms of vitiligo.

Adolescent↗
PubMed1999

Sun and skin. Role of phototype and skin colour.

The study of the biological effects of sun on the skin is one of the most topical questions in the recent dermatological literature. Interest in these effects has grown since it was demonstrated that the sun accelerates intrinsic skin ageing and is a principal factor for skin cancer. Skin damage caused by the sun is mainly due to UV radiation. Skin damage certainly has ancient roots, but has undergone sudden changes since man began to migrate to different geographical areas, for example when northern European populations colonised sunny areas close to equator. It is not a coincidence that the highest incidence of sun induced neoplasias is observed among white population of Australia. This epidemiological finding focused the interest towards the identification of phenotypic factors conditioning skin response to sunlight, and hence towards the definition of the so called phototype. After the fundamental work of Fitzpatrick based on sun exposure history more recent studies have shown that skin response to UV-rays can be predicted, to a good approximation, by skin colorimetry. Therefore this simple, cheap and non invasive measurement enables to predict sun reactivity skin type and to evaluate the melanoma risk.

Colorimetry↗
PubMed1998

Altered expression of the alpha2 laminin chain in psoriatic skin: the effect of treatment with cyclosporin.

The histopathological pattern of psoriasis is characterized by dermal inflammatory reaction and hyperproliferation of the epidermis. The mechanism of the epidermal hyperproliferation is not completely understood, but it is probably modulated by the basal lamina (BL), the alterations of which have not been described. We performed the present study to evaluate the expression of the alpha1, alpha2, beta1 and gamma1 laminin chains and collagen IV in the BL of active psoriasis vulgaris before and after cyclosporin treatment administered until the psoriasis was in remission. The results showed that the alpha2 chain is weak and irregular in the lesions, while the alpha1, beta1 and gamma1 chains and collagen IV are normal, with intense and continuous reaction. In the same subjects, this alteration was absent in skin that was clinically unaffected. After treatment with cyclosporin, the altered expression of the alpha2 chain returned to normal in the healing lesions.

Adult↗
PubMed1998

A new model of epidermal culture for the surgical treatment of vitiligo.

BACKGROUND: Vitiligo can be successfully treated with grafts of autologous cultured epidermal cells. OBJECTIVE: To evaluate the efficacy of autologous grafting of epidermal cells, cultured by an original method, in the treatment of localized vitiligo refractory to other therapies. METHODS: Autologous normally pigmented skin was used to culture keratinocytes and melanocytes on a supporting layer of biomaterial (Laserskin), which was grafted directly onto achromatic skin after de-epithelialization with liquid carbon dioxide. The percentage area of repigmentation was calculated by image analysis. RESULTS: Initial repigmentation of the treated areas was observed 1 month after treatment. Repigmentation continued to increase for 3 months after grafting. Follow-up at 3, 6, 12, and 18 months showed almost complete repigmentation in six out of 11 cases. In four other patients, 40-71% of the grafted achromatic area was repigmented. In one patient, repigmentation was impeded by sepsis. CONCLUSIONS: The method was found to be effective in the treatment of localized vitiligo refractory to other treatments. The therapeutic procedure was simple, reproducible, and easy to use.

Adult↗
PubMed1998

Instrumental measurement of skin colour and skin type as risk factors for melanoma: a statistical classification procedure.

A statistical procedure to evaluate melanoma risk in Caucasian subjects on the basis of colorimetric measurement of skin colour and Fitzpatrick phototype is described. One hundred and sixty melanoma patients and 546 randomized healthy subjects of similar age, sex and place of origin were examined in the same period for skin colour using a tristimulus colorimeter and for Fitzpatrick phototype. A clinical score for classification purposes was obtained by statistical discriminant analysis with multivariate data transformation and dimension reduction techniques. A Fisher linear classifier was chosen for its simplicity and robustness in correctly predicting melanoma risk in new subjects. The classification rule was designed to avoid classifying subjects at high risk for melanoma as low risk, i.e. to give a negligible number of false negatives at the expense of more false positives. The procedure is objective and readily adapted to different clinical requirements. This is only a preliminary study but it is hoped that by performing more complex statistical analyses, e.g. neural networks, and adding other parameters (proven risk factors such as number of naevi) the performance will be further improved.

Colorimetry↗
PubMed1998

Relationship between minimal phototoxic dose and skin colour plus sun exposure history: a neural network approach.

Before beginning PUVA-therapy it is important to accurately gauge an individual's degree of psoralen photosensitivity. This determination is usually based on an individual's skin phototype or minimal phototoxic dose. Since minimal phototoxic dose is technically complex and time consuming to measure, sun reactivity skin phototype is often used instead; however, it has recently been shown that skin phototype lacks specificity as a predictor of an individual's minimal phototoxic dose. In this study, an artificial neural network was developed to attempt to predict the minimal phototoxic dose from skin colour measurements combined with skin phototype. Our results showed that minimal phototoxic dose was predicted with an error less than 1 J/cm2 in only about half the subjects. In conclusion, minimal phototoxic dose probably cannot be predicted with sufficient accuracy on the basis of skin colour and skin phototype alone.

Adult↗