PubMed Health⌕ Search

Biomedical subjects

L Andreassi

Publications and source records attributed to L Andreassi.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1997

Extracorporeal photochemotherapy restores Th1/Th2 imbalance in patients with early stage cutaneous T-cell lymphoma.

Extracorporeal photochemotherapy (ECP) has been shown to be a potent activator of peripheral blood macrophages because it causes a marked release of macrophage-dependent proinflammatory cytokines, and it is therefore currently considered to be a safe and non-toxic immunomodulatory treatment. On this basis we studied the function of peripheral blood mononuclear cells (PBMC) in eight patients with early stage (Ib) cutaneous T-cell lymphoma (CTCL), before and 1 year after ECP, together with their clinical and histological responses. In particular we evaluated in vitro phytohaemagglutinin (PHA)-stimulated proliferation and production of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) as well as lipopolysaccharide (LPS)-induced production of IL-12. Before treatment we observed that PBMC of patients produced significantly higher levels of IL-4 and lower levels of IFN-gamma and IL-12 than those of healthy control subjects. After 1 year of ECP, IL-4, IFN-gamma and IL-12 production no longer differed from that of control subjects. Moreover, we observed a good clinical result matched by histological response. Our data confirm that early-stage CTCL patients show a predominantly type-2 immune response that might be responsible for several immunological abnormalities found in this disease. We have demonstrated that ECP reverses the T-helper type 1/T-helper type 2 (Th1/Th2) imbalance and may therefore be considered an efficient biological response modifier.

Aged↗
PubMed1997

Relationship between skin color and sun exposure history: a statistical classification approach.

In this study our aim was to determine the biophysical values of constitutive skin color in Caucasians and to define the correlation between skin color and phototype assessed according to the Fitzpatrick method. Constitutive skin color was measured on the buttock, with a Minolta CR-200 colorimeter, in a population-of 557 consecutive subjects belonging to phototype categories I, II, III and IV. The colorimeter expresses the results in five different color systems. We used the "Yxy" and L*a*b* systems, which are the most widespread in dermatology. Statistical analysis of the data showed that the "Yxy" system is even more discriminant than the L*a*b* system when the Fitzpatrick classification scheme is adopted as the reference and shows a poor ability to correctly classify the intermediate phototypes (II and III). On the contrary the "Yxy" system performs well in distinguishing phototypes I and IV. To establish whether this low discriminating capacity for phototypes II and III is related to a low discriminating capacity of the method suggested by Fitzpatrick or by our procedure, an objective technique (minimal erythemal dose) should be used to evaluate the percentage errors of classification of both the Fitzpatrick method and instrumental measurement of skin color. The results of such a study are extremely important because the evaluation of skin color is objective, simple and has potential applications in dermatology and cosmetology.

Adult↗
PubMed1997

Extracorporeal photochemotherapy induces a significant increase in CD36+ circulating monocytes in patients with mycosis fungoides.

BACKGROUND: In patients with Sezary syndrome undergoing extracorporeal photochemotherapy it is currently thought that photodamage of a congruent number of pathogenic circulating T cells is a necessary condition for a specific anticlonal response to be induced against these cells by the immune system. However other mechanisms of action, such as the induction of release by photoirradiated monocytes of some cytokines, are thought to cooperate in the induction of a therapeutic response. OBJECTIVE: We investigated the effects of extracorporeal photochemotherapy on peripheral blood mononuclear cells in seven stage Ib cutaneous T cell lymphoma patients. METHOD: Samples of peripheral blood were taken before starting extracorporeal photochemotherapy (baseline), and before the 3rd and 6th cycle of treatment, and then incubated with specific monoclonal antibodies. RESULTS: The results showed a significant increase of CD8+ and CD36+ and a significant decrease of CD25+ in all the treated patients. CONCLUSION: Our results show that extracorporeal photochemotherapy is able to induce an increase of CD36+ cell in peripheral blood of patients with mycosis fungoides in its early stages. This subset of monocytes could be involved in the complex mechanism of action of extracorporeal photochemotherapy.

Aged↗
PubMed1997

The behaviour of Sarcoptes scabiei var. hominis in human skin: an ultrastructural study.

The biology of Sarcoptes scabiei var. hominis is poorly understood because of the lack of an in vivo or in vitro propagation system. To obtain more information on the mite behaviour in its natural habitat we conducted an ultrastructural study of burrows in a number of patients with common scabies. Scanning electron microscopy furnished attractive images of the tunnel, parasite body and eggs architecture and demonstrated the presence of holes in the tunnel roof probably representing aeration structures. Transmission electron microscopy showed a marked keratinocyte damage around burrowing mites, well evident ahead of the mite capitulum also. Faecal pellets containing keratinocyte micro-organelles (melanosomes and mitochondria) were documented in posterior midgut. For the first time we disclosed the adhesion mechanism of eggs to the burrow floor. We showed that the typical finger-like projections of the outer layer of the egg shell gradually disappear where the eggs are in contact with the tunnel floor. This allows the inner layer of the egg shell to fuse and stick with the damaged keratinocytes lining the tunnel floor. Our observation substantiates that Sarcoptes scabiei produces a proteolytic substance (salivary secretions?) that has a key role in its life cycle allowing burrowing, feeding and eggs-burrow adhesion.

Adolescent↗
PubMed1996

A case of cryofibrinogenaemia responsive to stanozolol.

Cryofibrinogen is a plasma protein complex whose presence in the peripheral blood is generally asymptomatic, but may sometimes cause multiple thromboembolism in the skin, lung and myocardium. The pathological manifestations associated with cryofibrinogenaemia have been treated with plasmapheresis and fibrinolytic drugs such as streptokinase, streptodornase and/or urokinase. Good results have recently been reported with stanozolol. This prompted us to treat a patient suffering from cryofibrinogenaemia with this androgenic hormone. The patient was a 66-year-old woman with rapidly evolving leg ulcers. Stanozolol was orally administered at 4 mg b.i.d. for 5 months and then gradually reduced. Plasma cryofibrinogen disappeared after 45 d from the start of therapy and cutaneous ulcers healed in 5 months.

Aged↗