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Biomedical subjects

A Tosti

Publications and source records attributed to A Tosti.

At least 127 records · Page 7Linked to original sources
PubMed1995

Euxyl K 400: incidence of sensitization, patch test concentration and vehicle.

The aim of this study was to verify the most suitable vehicle and concentration for testing Euxyl K 400 and its individual ingredients, and to evaluate the prevalence of sensitization to this preservative over the years in Italy. From January 1991 to October 1994, Euxyl K 2.5% pet. was positive in 99 patients (35 male, 64 female) out of 3455 (2.8%). Of these, 22 out of 855 patients had a positive reaction during 1991 (2.6%), 29 out of 1037 in 1992 (2.8%), 28 out of 858 in 1993 (3.3%), and 20 out of 705 in 1994 (2.8%). 51 of the 99 patients with a reaction to Euxyl K 400 2.5% pet. showed a positive reaction to dibromodicyanobutane 0.5% pet. and 2 to phenoxyethanol 5% pet. The results of patch testing with serial dilutions of Euxyl K 400 in different vehicles indicate that water is a good vehicle for testing the preservative. However, since Euxyl K 400 is only hydrosoluble to a limited extent, the maximum concentration that can be tested using water is 0.5%, and so with this concentration about 40% of sensitized patients are missed. The results of patch testing with serial dilutions of Euxyl K 400 in petrolatum demonstrate that concentrations lower than 2.5% are not suitable for detection of all sensitized patients. Euxyl K 400 in ethanol frequently causes irritant reactions without offering significant advantages in detecting sensitized patients.

Adolescent↗
PubMed1995

The various clinical patterns of xanthoma disseminatum. Considerations on seven cases and review of the literature.

BACKGROUND: Xanthoma disseminatum (XD) is a rare mucocutaneous xanthoma nowadays classified as a benign non-Langerhans cell histiocytosis. OBJECTIVE: We studied 7 cases of XD with a long follow-up and reviewed the literature in order to compare and discuss previous reports. METHODS: We studied clinical manifestations, course, histopathologic, ultrastructural and immunohistochemical findings of 7 cases of XD followed for 1-20 years. RESULTS: We report our findings and compare our cases with those described in the literature. CONCLUSIONS: XD and Langerhans cell histiocytosis were distinguished by clinical differences, as well as ultrastructural and immunohistochemical methods. Three clinical patterns of XD appeared to emerge in our group of patients and in the cases reviewed from the literature.

Adult↗
PubMed1995

Idiopathic atrophy of the nails: clinical and pathological study of 2 cases.

BACKGROUND: Whether idiopathic atrophy of the nails (IAN) should be considered a separate entity or a clinical variant of nail lichen planus is still controversial. OBJECTIVE: We report here the pathological study of 2 patients with IAN. METHODS: Our patients had similar clinical features consisting of severe nail atrophy with and without pterygium. RESULTS: The nail matrix architecture was markedly deformed with complete disappearance of the keratogenous zone that was replaced by a 3- to 10-cell-thick granular layer. CONCLUSION: The hypothesis that IAN is an acute and self-limited variety of lichen planus is still the most presumable. Even though this hypothesis can not be definitely proven, it is nevertheless not excluded by the clinical and pathological findings of our cases.

Adult↗
PubMed1995

Diffuse partial woolly hair.

We report here a 14-year-old girl with diffuse partial woolly hair. The patient presented mild hair loss associated with the presence of fine, short and kinky hairs closely interspersed with the normal hair throughout the scalp. The pathology of the scalp revealed the presence of intermediate-sized hair follicles regularly intermingled with normal follicles in each follicular unit. The possibility that diffuse partial woolly hair may result from a progressive miniaturization of the hair follicles may explain the presence of evident hair thinning in several adult patients affected by this rare abnormality.

Adolescent↗
PubMed1994

Characterization of cultured nail matrix cells.

BACKGROUND: Cultures of epidermal cells are commonly used to study skin biology and differentiation. Recently a method to culture nail matrix cells has been established. OBJECTIVE: We report the biologic characteristics of nail matrix cells in vitro compared with those of epidermal keratinocytes. METHODS: Human nail matrix cells were isolated and cultured in defined medium. Electron-microscopic examination, growth rate, integrin expression and keratin synthesis pattern were evaluated. In addition, the cells were cultured in serum-containing medium. RESULTS: Nail matrix cells appear to be larger than human epidermal keratinocytes and, at the ultrastructural level, they contain a higher euchromatin/heterochromatin ratio and a lower nucleus/cytoplasm ratio and have a higher growth rate. The synthesis of "hard" keratins was detected at all calcium concentrations. Immunofluorescence analyses showed the expression of alpha 2, alpha 3, and alpha 6 integrin subunits. When cultured in serum-containing medium, nail matrix cells produced an outgrowth of epithelium and a spontaneous migration phenomenon associated with a tendency to stratify in a semilunar area that resembles the architecture of the nail matrix. The pluristratified epithelium showed characteristic markers of nail differentiation. CONCLUSION: Culture of nail matrix cells may represent a useful model to study the biologic properties of nail structure, alterations in some nail diseases and the effects of drugs.

Cell Division↗
PubMed1994

Characterization of nail matrix melanocytes with anti-PEP1, anti-PEP8, TMH-1, and HMB-45 antibodies.

BACKGROUND: The normal nail matrix contains quiescent melanocytes with a peculiar arrangement and behavior. OBJECTIVE: Our purpose was to identify nail matrix melanocytes with antibodies that recognize melanocytic cells in tissue sections. METHODS: We used the polyclonal antibodies anti-PEP1 and anti-PEP8 and the monoclonal antibody TMH-1, which recognize melanocytic enzymes, and the monoclonal antibody HMB-45, which reacts with melanoma cells and fetal melanocytes, but not with normal adult melanocytes. Nail matrix specimens were obtained from longitudinal specimens of eight white patients with ingrown toenails. Specimens from normal adult forearm skin were used as controls. RESULTS: All nail specimens gave similar results. Dendritic melanocytes were more numerous in the distal than in the proximal nail matrix. They were not restricted to the basal layer, but were also found in the suprabasal layers of the nail matrix epithelium. Melanocytes were seen both a single dendritic cells among the nail matrix keratinocytes and as small clusters that appeared irregularly distributed along the length of the nail matrix. Each cluster usually consisted of three to four cells. CONCLUSION: Even if normally quiescent, nail matrix melanocytes possess the key enzymes responsible for the formation of melanin. The suprabasal location of nail matrix melanocytes may be a consequence of the distribution of adhesion molecules in the nail epithelium. In fact, in the nail matrix alpha 2, alpha 3, and beta 1 integrins are not only expressed on the basal, but also on the fourth to fifth suprabasal layers, with suprabasal expression gradually decreasing from distal to proximal matrix. The behavior of nail matrix keratinocytes may cause the peculiar arrangement and behavior of nail matrix melanocytes.

Antibodies, Monoclonal↗
PubMed1994

Nail matrix hypergranulosis.

Nail pathology shares some common features with skin pathology, but it also has its own peculiar aspects. The anatomical and physiological characteristics of the nail unit probably play a major role in determining these pathological differences. Although the presence of keratohyaline granules is a normal feature of the skin, there is no granular layer in the normal nail matrix. As a consequence, nail matrix hypergranulosis should be considered a separate entity from skin hypergranulosis. In our review of 150 longitudinal nail biopsy specimens, keratohyaline granules were seen in the nail matrix of 24 cases of lichen planus, 29 cases of spongiotic trachyonychia, 10 cases of psoriasis, and three cases of Hallopeau acrodermatitis. In all cases, the presence of keratohyaline granules was associated with the absence of the normal keratogenous zone. Similar nail matrix features were detectable in three cases of malignant melanoma, two cases of primary systemic amyloidosis, and one case of histiocytoid hemangioma compressing the nail matrix. Our data suggest that inflammatory and compressive insults to the nail matrix cause both disappearance of the keratogenous zone and matrix keratinization with the formation of keratohyaline granules. Skin hypergranulosis reflects a hyperplasia of a normal skin component. In the nail matrix, however, hypergranulosis represents the appearance of structures not normally present. Nail matrix hypergranulosis should be considered a pattern of nail matrix reaction to different inflammatory insults. It is therefore more analogous to epidermal parakeratosis than to epidermal hypergranulosis.

Acrodermatitis↗
PubMed1994

Idiopathic trachyonychia (twenty-nail dystrophy): a pathological study of 23 patients.

We report the clinical features and pathological findings in 23 patients with idiopathic trachyonychia (twenty-nail dystrophy). Clinically, the nail changes in the majority of patients consisted of the typical 'sandpapered' appearance, with a rough, lustreless nail plate. In some, however, the nail plate abnormality was less severe, with numerous small, superficial pits, which imparted a shiny appearance to the surface of the nail. Histology of nail biopsy specimens showed spongiotic changes in 19 patients, psoriasiform features in three, and features of lichen planus in one patient. The mean follow-up of these patients was 2 years, during which time none developed alopecia areata or mucocutaneous lesions. Idiopathic trachyonychia is therefore a consequence of several inflammatory disorders, which produce a disturbance of nail matrix kinetics. The course of the inflammation and the extent of the inflammatory process within the nail matrix produce two different patterns of nail plate surface abnormalities.

Adolescent↗