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Biomedical subjects

P Danese

Publications and source records attributed to P Danese.

13 recordsLinked to original sources

Familial reticulate acropigmentation of Dohi.

Reticulate acropigmentation (RA) comprises dyschromic disorders that generally have an autosomal dominant pattern of inheritance, Two main forms of RA have been described: reticulate acropigmentation of Kitamura (RAK) and reticulate acropigmentation of Dohi (RAD). We observed a 21-year-old white woman who had progressive reticulate hyper- and hypopigmentation on the volar surface of her forearms and the dorsa of her hands. Many of her relatives have similar lesions. There were no pits or breaks in the epidermal ridge pattern on the palms. A biopsy specimen revealed areas with an excess of melanin in the basal layer alternating with others in which melanin was totally absent, Electron microscopic findings in a hypermelanotic area showed an increased number of melanocytes with high metabolic activity. In the hypomelanotic areas the melanocytes were morphologically abnormal with melanosomes at the early stages of development.

Adult↗

The genetics of IgG4 deficiency: role of the immunoglobulin heavy chain constant region and HLA loci.

IgG4 deficiency is very common (1/400 in the Italian population) and provides a good model for analyzing the genetic factors involved in Ig subclass deficiencies. We have previously reported an association between some immunoglobulin heavy chain constant region (IGHC) polymorphisms and the IgG4 deficiency. The associated polymorphisms spanned the region between the GP and the G4 genes. A larger sample composed of 50 healthy blood donors with IgG4 deficiency (less than 0.001 g/l IgG4), not carrying homozygous gene deletions, together with 82 first-degree relatives is now examined. The results confirmed the association of the deficiency with IGHC polymorphisms, and detected a new association with the HLA-D locus with a strong additive effect between the two systems. However, despite these associations and a highly significant risk for IgG4 deficiency within families, close linkage with either IGHC or HLA loci was not apparent by the affected sib pair method. These findings suggest that several concomitant, possibly cooperating, genetic factors may be involved in IgG4 deficiency.

Chromosome Mapping↗

Positive patch tests to whole mite culture and purified mite extracts in patients with atopic dermatitis, asthma, and rhinitis.

Patch tests with Dermatophagoides were carried out by different authors on patients with atopic dermatitis (AD) employing methods varying both in the type of allergen and in the way of performing the test. In order to examine and compare different methods and various allergenic materials and to define better the indications for this test, we performed patch tests with whole mite culture or purified mite extracts on 72 patients with AD, 40 subjects with mucosal atopy, and 32 healthy volunteers, employing different techniques of application. Positive results were obtained in 51.5% of patients with AD with specific IgE to Dermatophagoides, in 43.6% of patients with AD without this specific IgE and in 40% of subjects affected by mucosal atopy and having specific IgE to Dermatophagoides. From a technical point of view the simple application of the allergenic material on healthy skin gave the best results. Our data show that patch tests with Dermatophagoides extracts could contribute to a better immunoallergologic characterization both of patients with AD and patients with mucosal atopy.

Adolescent↗

Contact sensitization to textile dyes: description of 100 subjects.

We have described 100 subjects sensitized to textile dyes. Of these, 16 had clinically been suspected of having a textile dermatitis from among 1145 patients referred for patch testing. 41 patients were identified from among 861 consecutive subjects tested with the GIRDCA (Italian Research Group on Contact and Environmental Dermatitis) standard series supplemented with 4 disperse dyes (Disperse Blue 124, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3). The remaining 43 patients were identified from among 746 subjects tested with the GIRDCA standard series, supplemented with the 4 disperse dyes mentioned above and a further series of 12 other textile dyes. The clinical picture was extremely variable: most patients had a typical eczematous dermatitis, but we also observed persistent erythematous-wheal-type reactions, a transient urticarial dermatitis and an erythema-multiforme-like eruption. Among these textile dyes, Disperse Blue 124 caused most reactions. With the addition of the 4 disperse dyes to the GIRDCA standard series, we identified 4.8% sensitized to textile dyes, a much higher figure than the 1.4% observed among patients being patch tested on the basis of their history and the clinical findings; the addition of a further 12 textile dyes to the series further increased the detection rate to 5.8%. We stress the importance of routinely patch testing with textile dyes, which can help to elucidate the cause of certain kinds of atypical dermatitis.

Adolescent↗

Contact sensitization among ceramics workers.

139 workers from 3 ceramics factories underwent dermatological and allergological examination, using standard and occupational patch test series, in order to evaluate the prevalence of dermatitis and contact sensitization, to identify the most important sensitizing substances in the ceramics industry, and to correlate the results with possible risk factors such as atopy. Hand dermatitis had affected 37% of the subjects examined. 27% of the workers were sensitized to 1 or more allergens. Of 52 subjects with dermatitis, 37% had allergic contact dermatitis and 63% irritant contact dermatitis. 18 subjects were found to be sensitized without showing any previous or present clinical symptoms. Atopy tended towards correlation with the overall incidence of dermatitis, though not with the prevalence of sensitization.

Ceramics↗

Patch and prick test study of 593 healthy subjects.

593 recruits selected by the Military Health Service as being healthy and without a history of present or previous dermatitis, or ocular refraction defects, were patch tested with the GIRDCA (Italian Research Group on Contact and Environmental Dermatitis) standard series. Of these, 336 were also patch tested with substances used in the processing and dyeing of textiles and prick tested with 8 major allergens. 74 (12.5%) reacted to 1 or more substances. The most frequent sensitizers were: thimerosal (28 cases), ammoniated mercury (7 cases), phenol-formaldehyde resin (6 cases), parabens, nickel and Disperse Red 17 (4 cases each). 113 recruits reacted to 1 or more prick test allergens. We have demonstrated the importance of establishing such reference values in healthy groups for the correct evaluation of data collected from selected groups.

Adolescent↗

Analysis of the rhodopsin and peripherin/RDS gene in two families with pattern dystrophy of the retinal pigment epithelium.

Mutations of the peripherin/retinal degeneration slow (RDS) gene have been reported in autosomal dominant retinitis pigmentosa and variable forms of pattern dystrophy of the retinal pigment epithelium. We screened the rhodopsin and the peripherin/RDS gene in the members of two families who presented the clinical features of pattern dystrophy of the retinal pigment epithelium transmitted as an autosomal dominant trait. No migration patterns were detected in single strand conformation polymorphism or hydrolink gels. Both the rhodopsin and the peripherin/RDS gene were normal in one family. In the second, the proband had a normal rhodopsin gene and, although he passed a different haplotype to each of his affected daughters, there was no linkage with the peripherin/RDS gene. The origin of the retinal disturbance in our two pedigrees must therefore be sought, if indeed DNA is involved, elsewhere in the genome. Our findings provide additional evidence that pattern dystrophies of the retinal pigment epithelium may be pathogenically related in spite of different etiological origins. The genetic polymorphism can probably account for the wide range of phenotypes.

Eye Proteins↗

[Contact sensitization to thimerosal in healthy subjects].

The aim of our study was to evaluate the prevalence of thimerosal allergy in subjects free of dermatitis. 256 recruits, selected by the Military Health Authorities as healthy subjects, without dermatitis or ocular defects, underwent allergological examination. The percentage of sensitization observed (6.25%) was compared to that found among 2150 patients, consecutively admitted to the Allergological Service of our Department, with suspected allergic dermatitis. Here we found 76 positivities (3.53%). Contact sensitization to ammoniated-mercury is lower among thimerosal-negative subjects (1.88%) than among both the healthy group of thimerosal-positive subjects (12.5%) and thimerosal-positive patients (11.84%). In the group of 76 positive patients it was not possible to relate the sensitization to thimerosal to either a particular clinical dermatological picture or to a specific exposure.

Adolescent↗