Precocious puberty in a boy with a widespread linear epidermal naevus

A 7-year-old boy with a systematized verrucous epidermal naevus, multiple pigmented naevocytic naevi and precocious puberty is described. The possible basis for this previously unreported association of abnormalities is discussed.

Dermatology and the human gene map

Chromosomal localization has been established for many genetic traits. Gene mapping may lead to the identification of disease genes, an understanding of pathogenesis, and the development of rational therapy, as well as facilitating antenatal diagnosis and genetic counselling. 'The new genetics' is therefore of great interest to the clinician. Unfortunately the complex technology and unfamiliar vocabulary of molecular biology often deter non-specialists from keeping abreast of these developments. This account explains the principles of gene mapping, discusses its relevance to dermatologists, and lists the established loci of dermatologically important genes.

Rothmund-Thomson syndrome: a report of two patients and a review of the literature

Two siblings with poikiloderma, short stature and other abnormalities are described. They were originally reported as having Morquio syndrome; subsequently, mucopolysaccharidosis was excluded biochemically and they were classified as 'a newly recognized syndrome of connective tissue dysplasia'. It is now clear that their disorder is the Rothmund-Thomson syndrome (RTS).

Accessible conformations of melanin-concentrating hormone: a molecular dynamics approach

Molecular dynamics simulations have been used to search for the accessible conformations of the melanin-concentrating hormone (MCH). The studies have been performed on native MCH and two of its peptide fragments, a cyclic MCH(5-14) fragment and a linear MCH(5-14) fragment. An analysis of the molecular dynamics trajectories of the three peptides indicates that two regions of the peptide have characteristic conformational properties that may be important for the biological activity. One is a region around Gly8, which is conformationally mobile, and the other is around Pro13, which shows unusual rigidity. The molecular dynamics simulation results are discussed in terms of backbone structural features like beta turns, side-chain interactions, and orientations of the disulfide bridge. The results of this analysis are used to suggest new analogues that will modify the conformational features of the peptide and further define the conformational requirements for activity. Finally, the results are related to nmr studies of the peptide and reveal agreements between the experimental nuclear Overhauser effect constraints and some of the accessible conformations obtained from the simulation.

Compound allergy to a skin marker for patch testing: a chromatographic analysis

We present details of a patient who was demonstrated to have contact allergy to a solution used to mark sites of application of patch tests, during investigation of allergy to gold and nickel. Negative results were obtained when patch testing was performed using the individual constituents of the marker solution (gentian violet, dihydroxyacetone and acetone). Chromatographic analysis of various combinations of these chemicals did not identify a chemical derivative which might have caused this reaction.

Antigenic stimulation during ultraviolet therapy in man does not result in immunological tolerance

People receiving therapy with either 8-methoxypsoralen plus long wavelength ultraviolet radiation (PUVA) or medium wavelength ultraviolet radiation (UVB) have been studied to see whether their unresponsiveness to the contact sensitizer dinitrochlorobenzene (DNCB) is a form of immunological tolerance. It was confirmed that both PUVA and UVB therapy impair sensitization by DNCB:4/13 PUVA-treated and 9/29 UVB-treated psoriatic subjects became sensitized by a dose of DNCB which sensitizes 100% of untreated patients. Subjects unsuccessfully sensitized during PUVA therapy could subsequently be sensitized perfectly normally. Subjects unsuccessfully sensitized during UVB therapy showed slight impairment of subsequent sensitization which was not statistically significant, and which was probably a persistent effect of UVB exposure. In conclusion, the temporary unresponsiveness seen in human subjects exposed to antigens during PUVA or UVB therapy is not due to immunological tolerance.

Generating alternatives in nursing: turning curriculum into a living process

The transfer of nursing education into higher education institutions is challenging nurses to re-think educational structures and processes. Traditionally, nursing education has used objective curriculum models which tend to reinforce bureaucratic rather than professional values. Critics suggest that these models, by their failure to incorporate social, political and cultural realities, contribute to theory-practice dichotomies. This paper shares the intentions of Deakin University's School of Nursing in developing alternative approaches to curriculum design and to learning and practising nursing.

Genetic counselling in hypomelanosis of Ito: case report and review

A 27-year-old male with hypomelanosis of Ito (HI) is reported. One of his two children had a postaxial ray defect of one leg but neither had cutaneous features of HI. Somatic mosaicism for a gene defect lethal to ectodermal derivatives offers the best explanation for HI in males, with consequent negligible recurrence risk. The limb defect is considered coincidental. The excess of girls with HI could be due to a female cohort with incontinentia pigmenti (IP) which may be indistinguishable: counselling of females must therefore take account of possible X-linked inheritance.

Allergy to non-toxoid constituents of vaccines and implications for patch testing

We report 3 patients with persistent symptoms at vaccination sites. All were allergic to aluminium and one to thiomersal and neomycin too. Aluminium allergy causes false positive patch test reactions and we propose methods of patch testing patients with symptoms at vaccination sites in order to avoid this problem. The practical relevance of allergy to non-toxoid constituents of vaccines is discussed.

Recovery of cutaneous immune responsiveness after PUVA therapy

We studied sensitization to dinitrochlorobenzene (DNCB) in psoriatic patients before, during and 2, 4, and 6 weeks after a course of photochemotherapy (PUVA). The inhibition of sensitivity observed during PUVA was completely reversed after 6 weeks. Thus the PUVA-mediated inhibition of cutaneous immune responsiveness is of short duration. However, whether there are long-term sequelae remains to be established.

Anhidrotic and achromians lesions in incontinentia pigmenti

Three women subsequently shown to have incontinentia pigmenti (IP) presented with white hairless streaks on the limbs as the predominant cutaneous abnormality. Seven other patients with IP diagnosed in infancy were reviewed to establish the frequency of this sign. It was found in all of them, and in the otherwise unaffected mother of three affected girls. A focal absence of sweating in these lesions is reported here for the first time. There are other similarities with anhidrotic ectodermal dysplasia, suggesting a genetic overlap between these two X-linked conditions.

The effect of altering area of application and dose per unit area on sensitization by DNCB

We have investigated the contributions of dose per unit area and area of application to the degree of sensitivity induced by dinitrochlorobenzene (DNCB). Subjects sensitized with 35.4 micrograms/cm2 showed equal sensitization whether the total dose was 250 micrograms applied to 7.1 cm2 or 62.5 micrograms applied to 1.8 cm2. Three groups of subjects were sensitized with 16.4 micrograms/cm2 applied as 56 micrograms on 3.5 cm2, 116 micrograms on 7.1 cm2 or 232 micrograms on 14.2 cm2. Although the total dose changed by a factor of four, the proportions of subjects sensitized were comparable (66, 50 and 55% respectively), and their degrees of reactivity were similar. This contrasts with previous findings that when the area of sensitization was fixed and the concentration was increased over a similar range, highly significant increases in the proportion of sensitized subjects and degree of reactivity occurred.

Susceptibility and amplification of sensitivity in contact dermatitis

We have examined the hypothesis that people who develop contact allergies to environmental substances do so because they have heightened susceptibility. Analysis of data from 2200 consecutive patients tested with the 20 commonest antigens in a patch-test clinic showed that more people developed multiple contact allergies than would be predicted from the frequency of single allergies; the excess was too great to be explained by chance and increased with number and rarity of the combinations of sensitizers. The possibility that this was due to enhanced individual susceptibility to sensitization rather than concomitant exposure to several sensitizers was confirmed by showing that patients with multiple allergies are more readily sensitized experimentally, and to a greater degree than normal, by dinitrochlorobenzene (DNCB), an unrelated antigen. The defect involves induction rather than expression of sensitivity. Amplification of the response to DNCB is proportional to susceptibility (calculated from the ratio of observed prevalence of multiple allergies to that predicted from the prevalence of single allergies) throughout the range from normal subjects, through those with a single sensitivity, to those with rare, multiple allergies. Therefore, we conclude that individual susceptibility is an important factor in the development of contact dermatitis, and occurs by a non-antigen-specific amplification of immune sensitization.