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Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by the triad of tyrosinase-positive oculocutaneous albinism, bleeding diathesis due to storage-pool deficiency of platelets, and a lysosomal ceroid storage disease. The disorder is particularly frequent in Puerto Rico and in an isolated village in the Swiss Alps. We have used a linkage disequilibrium mapping approach to localize the HPS gene in both of these groups to a 0.6 centiMorgan interval in chromosome segment 10q23.1-q23.3. These results indicate that the Puerto Rican and Swiss forms of HPS are either allelic or that they result from mutations in very closely linked genes in this region. This region of distal chromosome 10q is syntenic to the region of mouse chromosome 19 that includes 'pale ear' (ep) and 'ruby-eye' (ru), which must be considered as potential murine homologues to human HPS.

As ferritin has been identified as an important factor in antioxidant defense in cultured human skin cells we evaluated the presence of ferritin in human skin in vivo and the modifications following irradiation with UVA I, UVA I + II, and solar simulating light by immunohistochemical analysis. We report that the putative protective protein ferritin is regularly present in the basal layer of unirradiated epidermis in vivo and that the induction of ferritin was dependent on wavelength and cell type. Following UVA I radiation, ferritin increased both in epidermal and in dermal tissue. The same response occurred, although to a lesser extent, with UVA I + II but did not occur following solar simulating radiation. Quantitative analysis for ferritin in cultured keratinocytes and fibroblasts from seven individuals following each UV spectra were also assessed by enzyme-linked immunosorbent assay. The induction of ferritin by UV was highly dependent on the waveband and cell type. UVA I and UVA I + II radiations induced ferritin expression in dermal fibroblasts up to 260% and 200% over basal levels, respectively. Solar simulating radiation produced only a small induction of ≈130% over basal ferritin levels in dermal fibroblasts. Ferritin increased in cultured fibroblasts as early as 3 h post-UVA with a peak at 6 h that remained until 48 h; there was no observable qualitative or quantitative increase seen in the undifferentiated cultured epidermal keratinocytes. Our findings indicate that the putative defense system of ferritin exists in human skin in vivo and its induction is dependent on UV spectra and cell type. The increased concentrations of this antioxidant in human skin following acute UV radiation could afford increased protection against subsequent oxidative stress. Key word: oxidative stress. J Invest Dermatol 111:159–163 1998

DNA damage by UV radiation plays an essential role in skin cancer induction. We report that even sub-erythemal doses of solar simulating radiation, are capable of inducing substantial nuclear damage, namely pyrimidine dimers and p53 induction in human skin in situ . The quantity and distribution of p53 induced in human skin by UV radiation depended highly on the waveband and dose of UV used. Solar simulating radiation induced very high levels of p53 throughout all layers in epidermal keratinocytes 24 hr following an erythemal dose (230 ± 15.9/1000 cells), and the induction followed a dose response. Following UVA I + II and UVA I radiations, p53 expression was approximately half of that seen with equivalent biological doses of solar simulating radiation (63.5 ± 28.5 and 103 ± 15.9, respectively). Expression of p53 was seen in basal cell keratinocytes at lower doses of UVA, but all layers of the epidermis were affected at higher doses. Pyrimidine dimer induction, however, was seen to be the same for equivalent biological doses of UVA I, UVA I + II and solar simulating radiations, which coincides with previous findings that pyrimidine dimers initiate the erythemal response and are implicated in skin carcinogenesis. When equivalent biological doses of pure UVA are used with no UVB contamination, significant nuclear alterations occur in human skin in situ, which can approach those seen with UVB radiation. Our results suggest that DNA damage assessed in vivo by immunohistochemistry could provide a very sensitive endpoint for determining the efficacy of protective measures, such as sunscreens or protective clothing, against both UVB- and UVA-induced damage in human skin. Int. J. Cancer 76:201–206, 1998.© 1998 Wiley-Liss, Inc.

Ultraviolet radiation, and in particular UVA (320-400 nm), induces significant oxidative stress to human skin. Ferritin and glutathione have been shown to be among the more important molecules within human skin cells providing protection against this damage, the presence of lower levels of these anti-oxidants giving rise to increased cellular sensitivity to stress. We compared endogenous levels of ferritin and glutathione in human melanoma cells with normal human skin fibroblasts and keratinocytes, also the response of melanoma cells to oxidative stress with fibroblasts and keratinocytes. Ferritin levels were heterogenous in the untreated melanoma cell lines tested and remained the same following oxidative stress (UVA radiation) or hemin treatment. Epidermal keratinocytes were unaffected, as were the melanoma cell lines, but skin fibroblasts showed dose-dependent ferritin depletion. Similar results were seen for glutathione alterations resulting from UVA radiation : melanoma cell lines and epidermal skin keratinocytes remained unchanged following UVA radiation, while skin fibroblasts showed dose-dependent depletion. Our results show that human melanoma cells have low ferritin and glutathione levels, yet are resistant to oxidative stress.

We report 2 cases of clinically typical Meleda disease in a family from Herzegovina. Electron microscopy did not reveal major ultrastructural anomalies of keratinization; however, the transition from stratum granulosum to stratum corneum appeared to occur less abruptly than normally by a stepwise process suggesting a slowing down of terminal cornification.

Background: Retinoic acid (RA) cream treatment alters epidermal proliferation and differentiation in photoaged skin. Objective: To study the changes in the expression of markers of epidermal differentiation in photoaged skin following RA cream treatment. Methods: Ten subjects with photoaged skin were examined before treatment and at regular intervals during 12 months of once daily application of 0.05% tretinoin cream over the left forearm. Paraffin-embedded biopsy sections from the forearm were stained with loricrin, filaggrin, involucrin and cornifin antisera in addition to hematoxylin and eosin. The various layers were measured using a calibrated optical micrometer. Results: The thickness of the epidermis increased rapidly, reaching a substantial increase after 1 month of retinoid cream application and retaining it during the following 12 months. The stratum granulosum achieved a transient but substantial increase after 1 and 3 months. Except involucrin, the ratio between the layers expressing the various markers of epidermal differentiation and the epidermis significantly increased following tretinoin cream treatment. Conclusion: RA cream treatment not only increases the thickness of the epidermis but also the programming of late terminal epidermal differentiation, as expressed by the markers studied. Thus, RA appears to affect both proliferation and differentiation of keratinocytes in vivo.

Skin fibroblasts from certain patients with the photosensitivity dermatitis/actinic reticuloid syndrome show enhanced sensitivity to ultraviolet radiation compared to normal fibroblasts. To probe further the link between oxidative damage and this disease, we have obtained a more extensive set of cell lines from patients with a severe form of the disease and examined their sensitivity towards oxidative stress by measuring cell survival following UVA radiation (330-450 nm) or hydrogen peroxide treatment (0.1-2.4 mM). The activation of the stress gene, heme oxygenase, has also been assessed by measuring the accumulation of mRNA after hydrogen peroxide treatment. Our studies have confirmed that a slight ultraviolet sensitivity is a characteristic of photosensitivity dermatitis/actinic reticuloid syndrome cell strains and we further demonstrate that these cell lines are particularly sensitive to hydrogen peroxide with up to a three- to fourfold increased sensitivity as compared to normal controls. We also show that certain ataxia telangiectasia strains that are especially sensitive to hydrogen peroxide are also slightly sensitive to ultraviolet radiation. Hydrogen peroxide induces accumulation of mRNA for the oxidant-inducible stress protein, heme oxygenase, with similar kinetics (maximum mRNA accumulation 2-4 h following treatment) and with a similar range of magnitudes in both normal (6.6-20.6 times mRNA increase over basal levels) and photosensitivity dermatitis/actinic reticuloid (2.9-12.8 times) skin cells. Because cells from photosensitivity dermatitis/actinic reticuloid patients show increased sensitivity towards oxidative stress but show no significant change in oxidant activation of the heme oxygenase gene, we propose that the defect involves a late stage of processing of oxidative damage rather than a compromised free radical scavenging system.

Crude extracts of Panamian plants (153 representing 28 species from 21 families) have been screened for antifungal activity against Candida albicans and Cladosporium cucumerinum. Activity was asses...

A simple bioautographic agar overlay assay using Candida albicans as the indicator organism for the detection and activity-guided fractionation of antifungal compounds by thin layer chromatography has been developed. Inhibition of fungal growth was assessed by the detection of dehydrogenase activity with thiazolyl blue (methylthiazolyltetrazolium chloride; MTT). A series of clinically used antimycotic agents were tested in order to determine the sensitivity of the assay. The compatibility of the agar overlay technique with chemically modified silica gel (Diol and RP-18) plates and with various organic solvents was evaluated. The methodology is also applicable to the search for antibacterial compounds, as shown with Bacillus subtilis as a test organism.

A 22-month-old boy had xanthomatous skin lesions, neurofibromatosis, and chronic granulocytic leukemia. Histologic examination of the xanthomatous skin lesions disclosed juvenile xanthogranulomas. Twenty-three previously published cases of this association are reviewed.

Nucleolar organizer regions (NORs) are loops of DNA which are present within the nucleoli of cells that possess ribosomal RNA (rRNA) genes. NORs are associated with proteins which can be visualized by a simple silver staining technique. As the number of NORs appears to reflect cell and nuclear activity its determination in benign, intermediate and malignant conditions could be of help in their differential diagnosis. In this study, we investigated 35 fibrohistiocytic tumors of the skin of benign, intermediate and malignant potential from 32 patients: 15 fibrous histiocytomas (FH), 5 FH with atypia (AFH), 7 atypical fibroxanthomas (AFX), 5 dermatofibrosarcoma protuberans (DFSP) and 3 malignant FH (MFH). A one-step silver technique was used on formalin or Bouin fixed specimens. Ag-NOR counts from benign conditions (FH, AFH) significantly differed from that of their intermediate-risk (AFX, DFSP) and malignant (MFH) counterparts. Furthermore, in 2 cases (one AFX; one MFH) which twice recurred, Ag-NOR counts steadily increased with time. However, a distinction could not be achieved between AFX and MFH. Although Ag-NOR is a simple and valuable technique, it does not allow a definite distinction between malignant and intermediate processes, at least as far as fibrohistiocytic tumors of the skin are concerned.

Neonatal ichthyosis-sclerosing cholangitis (NISCH) syndrome, a rare autosomal recessive ichthyosis syndrome characterized by scalp hypotrichosis, scarring alopecia, ichthyosis, and sclerosing cholangitis, was described for the first time in 2002. It is caused by a mutation in the gene coding for the tight junction protein claudin-1. Only four patients carrying the same mutation of the CLDN1 gene have been described until now. We report a patient presenting with the clinical characteristics of NISCH syndrome and carrying a novel mutation in the CLDN1 gene.

BP180/collagen XVII is a hemidesmosomal transmembrane molecule serving as cell-surface receptor. Mutations in its gene cause junctional epidermolysis bullosa. Here, we report a patient with mutations in the gene for BP180/collagen XVII, COL17A1, but predominant phenotypic features of epidermolysis bullosa simplex. At birth, the proband presented with bullous lesions on the trunk, face, and hands. Ultrastructurally, hemidesmosomes were fairly normal, but the attachment of intermediate filaments with the hemidesmosomal plaques appeared to be impaired. Blister formation demonstrated both intraepidermal and junctional cleavage. Immunofluores cence staining with antibodies to keratins, several hemidesmosomal proteins, and the extracellular domain of BP180/collagen XVII showed normal staining patterns, whereas an antibody against the intracellular domain of BP180/collagen XVII yielded a negative immunofluorescence signal. Analysis of BP180/collagen XVII cDNA revealed a 1172 bp deletion corresponding to an in-frame deletion from Ile-18 to Asn-407 from the intracellular domain of the polypeptide. Mutation analysis of the COL17A1 gene disclosed a paternal nonsense mutation, R1226X, and a large maternal genomic deletion extending from intron 2 to intron 15, but no mutations in basal keratin genes. These findings underline the functional importance of the intracellular BP180/collagen XVII domain for the interaction of hemidesmosomes with keratin intermediate filaments and for the spatial stability of basal keratinocytes, and provide a functional explanation for the epidermolysis-bullosa- simplex-like phenotype. Further, the data demonstrate that defects in a given gene can cause unexpected phenotypes of epidermolysis bullosa categories, depending on the function of the affected protein domain.

A 20-year-old black patient with bullous systemic lupus erythematosus developed papular and vesicular lesions on the extensor surfaces of the extremities. Histologically, subepidermal blisters and pap

Epidermolytic hyperkeratosis is a hereditary skin disorder characterized by blistering and a marked thickening of the stratum corneum. In one family, affected individuals exhibited a mutation in the highly conserved carboxyl terminal of the rod domain of keratin 1. In two other families, affected individuals had mutations in the highly conserved amino terminal of the rod domain of keratin 10. Structural analysis of these mutations predicts that heterodimer formation would be unaffected, although filament assembly and elongation would be severely compromised. These data imply that an intact keratin intermediate filament network is required for the maintenance of both cellular and tissue integrity.

We report the case of a 30-year-old Nigerian patient with mycetoma of the foot without bone involvement caused by Fusarium sp.. Long-term administration of ketoconazole produced a s

The modification of ferritin in human skin cells in vitro and in vivo following infrared-A irradiation by immunohistochemical analysis and ELISA were evaluated. In addition, we observed that IR-A is not capable of inducing frank damage to DNA (pyrimidine dimers, p53), induction of oxidative stress proteins (heme oxygenase, nitric oxide, superoxide dismutase, heat shock proteins) or proteases (collagenase, stromelysin, gelatinase) involved in carcinogenesis and photoaging of the skin. in vivo, basal levels of ferritin were heterogeneous for all individuals tested but all showed ferritin to stain precisely in the basal layer of unirradiated epidermis. Following IR-A radiation, the ferritin increase was localized to epidermal tissue and showed an increase from 120 to 220%. Parallel to the in vivo analysis, dermal fibroblasts were cultured from six individuals. Quantitative analysis for ferritin in cultured fibroblasts was assessed by ELISA and increases were seen to be dose-dependent and up to 130% of basal levels of ferritin following infrared-A. Our findings indicate that the putative defense system of ferritin that exists in human skin in vivo can be induced by infrared-A radiation and that these wavelengths may prove to be beneficial for human skin. Importantly, following the same doses of IR-A that induced ferritin levels, there was no alteration seen for nuclear DNA type damage, oxidative stress proteins or proteases involved in the degradation of skin. The increased concentrations of this antioxidant in human skin following acute UV radiation could afford increased protection against subsequent oxidative stress.

It is well known today, that exposure of human skin to solar light can result in short-tern responses, such as immune suppression, erythema and pigmentation, and long-term responses, such as carcinogenesis and premature aging (C.C. Cross et al., 1987). These deleterious biological effects are mainly due to the UVB portion of the sun spectrum, but recently it was shown, that wavelengths in the UVA range can produce similar biological effects by other mechanisms (L. A. Applegate et al., 1995; 3. Fuchs et al., 1989). These mechanisms involve endogenous chromophores such as quinons, steroids, flavins, free porphyrins and heme containing enzymes, which act as photosensitizers when induced by UVA irradiation. Reactive oxygen species (ROS), including singlet oxygen, superoxide radical anion, hydroxyl radical and hydrogen peroxide are produced during these photosensitized reactions in such a manner, that the proantioxidant balance can be overwhelmed (Y. Shindo et al., 1994). The resulting photo-oxidative stiess due to these harmful ROS is considered to play a major role in causing modifications of DNA, lipids, proteins and carbohydrates in human skin (K. Punnonen et al., 1991), which could lead to several cutaneous manefestations mentioned above.

It is generally accepted that a UVA-induced erythema is difficult to detect except in the most sensitive individuals.As UVA effects on human skin and skin cells have been shown to depend strongly on anatomical body sites, UVA I, UVA I + II and solar simulator radiations were compared in their ability to induce erythema and melanin pigmentation responses in individuals with skin types I-IV on both previously sun-exposed (arms, forearms, thighs) and nonexposed body sites (buttocks).Erythema induction by UVA I on previously nonexposed skin sites followed a dose response in all skin types which was contrary to the absence of erythema induction seen on previously sun-exposed sites. Melanin expression followed a dose and skin type response and was shown to be more enhanced in previously exposed skin and in skin types III and IV. In contrast, UVA I + II induced erythema on nonexposed skin areas and to a lesser extent on frequently sun-exposed skin. Melanin production by UVA I + II was similar to that seen with UVA I alone in individuals of skin types II and III. Solar simulator radiation was very efficient in erythema induction regardless of previous sun exposure of skin.We have found that contrary to the widespread opinion that UVA and in particular UVA I could not induce a significant erythema, this waveband is capable of measurable erythema induction on skin nonexposed to sunlight. The diminished erythema induction by UVA I on chronically sun-exposed skin suggests the possibility of a defense mechanism against UVA-induced damage in this tissue.

Hermansky–Pudlak syndrome (HPS) is an often–fatal autosomal recessive disease in which albinism, bleeding, and lysosomal storage result from defects of diverse cytoplasmic organelles: melanosomes, platelet dense bodies, and lysosomes. HPS is the most common single–gene disorder in Puerto Rico, with an incidence of 1 in 1,800. We have identified the HPS gene by positional cloning, and found homozygous frameshifts in this gene in Puerto Rican, Swiss, Irish and Japanese HPS patients. The HPS polypeptide is a novel transmembrane protein that is likely to be a component of multiple cytoplasmic organelles and that is apparently crucial for their normal development and function. The different clinical phenotypes associated with the different HPS frameshifts we observed suggests that differentially truncated HPS polypeptides may have somewhat different consequences for subcellular function.

We describe a man with generalized congenital ichthyosiform dermatosis, severe cheilitis, and palmar and plantar hyperkeratosis with superficial blistering. Low-dose acitretin therapy induced areas of peeling skin, similar to that seen in the peeling skin syndrome. Histologically, the skin was moderately hyperkeratotic and the palmar blisters were subcorneal. Electron microscopy revealed that the splitting occurred within the desmosomal plaque. Ultrastructural and biochemical investigations indicated epidermal hypervitaminosis A, probably related to alteration of epidermal retinoic acid metabolism. This disease is proposed as a hitherto unreported variant of the peeling skin syndrome.

Four compounds including a flavone, an acetylenic lactone, a prenylated coumarin, and a 3-methyl ether flavone were isolated from the dichloromethane leaf extract of Baccharis pedunculata (Mill.) Cabr. (Asteraceae). The latter three compounds were identified to be responsible for the antifungal activity against some human pathogenic and phytopathogenic fungi. The most active compound, lachnophyllum lactone, an acetylenic lactone, showed a very high toxicity (LD50 2 micrograms/ml) against human keratinocytes.

— Activation of expression of the heme oxygenase (HO) gene appears to be involved in a cellular defense system in mammalian cells. We now demonstrate that while HO-1 mRNA levels are strongly inducible in dermal fibroblasts they are barely inducible in human epidermal keratinocytes following oxidative stress (UVA radiation and hydrogen peroxide). Paralleling this result was the observation that HO-2 mRNA levels were low in dermal fibroblasts but were high in epidermal keratinocytes. In neither case was the HO-2 gene inducible. The expression of the two HO genes led to enzymatic activity in both types of skin cells with an approximately 2.5-fold higher level of enzymatic activity present in keratinocytes compared with fibroblasts derived from the same biopsy. In addition, ferritin levels, which have been found to be augmented via the HO-dependent release of iron from endogenous heme sources, were two- to three-fold higher in keratinocytes compared with matching fibroblasts. This higher ferritin pool would result in an enhancement of cellular iron sequestering capacity that may confer increased resistance to oxidative stress. Indeed, keratinocytes showed less UVA radiation-dependent cell membrane damage than fibroblasts. These results are consistent with the hypothesis that HO expression in human epidermis and dermis is related to cellular defense mechanisms that operate in human skin.

OBJECTIVE: The authors determined the role of Candida colonization in the development of subsequent infection in critically ill patients. DESIGN: A 6-month prospective cohort study was given to patients admitted to the surgical and neonatal intensive care units in a 1600-bed university medical center. METHODS: Patients having predetermined criteria for significant Candida colonization revealed by routine microbiologic surveillance cultures at different body sites were eligible for the study. Risk factors for Candida infection were recorded. A Candida colonization index was determined daily as the ratio of the number of distinct body sites (dbs) colonized with identical strains over the total number of dbs tested; a mean of 5.3 dbs per patient was obtained. All isolates (n = 322) sequentially recovered were characterized by genotyping using contour-clamped homogeneous electrical field gel electrophoresis that allowed strain delineation among Candida species. RESULTS: Twenty-nine patients met the criteria for inclusion; all were at high risk for Candida infection; 11 patients (38%) developed severe infections (8 candidemia); the remaining 18 patients were heavily colonized, but never required intravenous antifungal therapy. Among the potential risk factors for candida infection, three discriminated the colonized from the infected patients--i.e., length of previous antibiotic therapy (p < 0.02), severity of illness assessed by APACHE II score (p < 0.01), and the intensity of Candida spp colonization (p < 0.01). By logistic regression analysis, the latter two who were the independent factors that predicted subsequent candidal infection. Candida colonization always preceded infection with genotypically identical Candida spp strain. The proposed colonization indexes reached threshold values a mean of 6 days before Candida infection and demonstrated high positive predictive values (66 to 100%). CONCLUSIONS: The intensity of Candida colonization assessed by systematic screening helps predicting subsequent infections with identical strains in critically ill patients. Accurately identifying high-risk patients with Candida colonization offers opportunity for intervention strategies.

The detection limits in two bioautographic assays have been determined for a series of antifungal compounds, including clinically used antimycotics, fungicidal agrochemicals, and various classes of secondary plant metabolites. Target organisms were the filamentous fungus Cladosporium cucumerinum and the yeast Candida albicans. For clinical agents and agrochemicals, the detection limits in the two assays reflected to a certain extent their known spectrum of activity. Most of the plant-derived compounds tested showed a positive response in both assays, but with detection limits varying by a factor up to tenfold. For screening purposes, it is thus advisable to use both tests, as some activities would otherwise go undetected. The MIC values of these substances were determined in order to verify a possible correlation with the detection limit in the bioautographic assays.

To examine the longitudinal and cross-sectional patterns of yeast colonization in critically ill patients using genotypic characteristics defined by contour-clamped homogeneous electric field (CHEF) gel electrophoresis, 322 clinical isolates of Candida species were prospectively collected from 29 critically ill patients under routine surveillance over a 6-month period. All isolates, recovered from multiple anatomic sites and from the same sites on different days, were characterized by several identification methods (germ tube test), phenotyping (API system), and genotyping (electrophoretic karyotyping). Electrophoretic karyotype (EK) was determined using pulsed field electrophoresis with the CHEF technique. We used a karyotyping system for Candida albicans (EK code) that facilitated intraspecies delineation. C. albicans colonized 83% of the 29 patients. Candida sp. strains isolated from an individual patient had an identical EK pattern, even when isolated from different body sites, and remained the same over a prolonged period, up to 140 days. EK delineated not only the different Candida species, but also different strains of C. albicans. Strains of C. albicans isolated from different patients were distinguished using the EK pattern, but not API system. Minor variations in EK pattern could be demonstrated in a minority of strains recovered from four patients and were interpreted as chromosomal rearrangements between parent strains. Severe candidal infections, including eight episodes of fungemia, occurred in 11 of 29 patients (38%). All patients had been previously colonized with strains with identical EK patterns. Infection occurred a mean of 25 days after initial surveillance cultures grew yeast. No horizontal transmission could be demonstrated during the study period. In conclusion, EK is a reproducible, stable marker allowing inter-, as well as, intraspecies Candida strain delineation. EK strain delineation is a useful tool in candidal epidemiologic and pathogenic studies. Yeast colonization with the same strain preceded infection in critically ill patients.

Aspergillus fumigatus secreted an inducible alkaline protease (AlPase) when cultivated in the presence of collagen (200 micrograms/ml) as sole nitrogen and carbon source. Proteolytic activity was maximum at pH 9.0 with azocollagen as substrate. The enzyme, which was the major protein found in the supernate of a liquid culture, was purified by ammonium sulphate precipitation and gel filtration. The Mr was determined to be 33 Kda by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The isoelectric point was estimated to be pH 8.2. Divalent cations strongly inhibited enzyme activity, whereas non-ionic detergents and reducing agents had no effect. A. fumigatus AlPase was totally inhibited by phenylmethanesulphonyl fluoride, antipain, chymostatin and alpha-2-macroglobulin. A. fumigatus AlPase is closely related to the A. oryzae AlPase, a serine protease of the subtilisin family, as attested by the antigen pattern seen by immunoblotting. The high collagenic activity and the ability of A. fumigatus AlPase to digest elastin could play a role in the invasion of the tissues by the fungus.

The diagnostic significance of 8 previously proposed minor features of atopic dermatitis (AD) was evaluated. The minor features studied were: nipple eczema, cheilitis, Dennie-Morgan infraorbital fold, pityriasis alba, anterior neck folds, wool intolerance, white dermographism and infraauricular fissuring. The incidence of these features was appreciated in 105 patients with typical AD (median age 8.5 years) and compared to that in 113 control subjects (median age 16 years). The ages of all studied individuals ranged from 7 months to 24 years. Two of these signs, anterior neck folds and the Dennie-Morgan infraorbital fold as defined by us, were shown to be of no diagnostic significance. The other 6 features were confirmed to be valuable diagnostic clues in AD.

The epidermis of superficial human skin samples could easily be separated from the dermis following incubation at +4 degrees C for 1 h in a solution containing 250-500 micrograms/ml thermolysin, a proteolytic enzyme hitherto mostly used for protein analysis. Light and electron microscopy revealed that the dermo-epidermal separation occurred at the basement membrane between the sites of bullous pemphigoid antigen and laminin and that the hemidesmosomes were selectively disrupted. The cohesion and morphology of the separated epidermis as well as the immunologic parameters investigated were not altered by this procedure. The clear cut dermo-epidermal separation produced by thermolysin treatment differed from the separation obtained with trypsin, which predominantly occurred between basal and suprabasal cells by disruption of desmosomes.

The Spitz nevus (large spindle and/or epithelioid cell nevus) is a benign acquired melanocytic tumour found predominantly in children and adolescents. Depending on the architecture (junctional, compound, dermal) and cytology (predominance of spindle or epithelioid cells, or presence of both cell types) several variants have been distinguished. A histological feature occasionally leading to diagnostic difficulties is the involvement of the suprabasal epidermis. The present study details the occurrence of intraepidermal involvement (pagetoid spread, nesting of cells, trans-epidermal elimination) according to the age of the patients. 89 cases of Spitz nevus were reviewed. There were 19 compound Spitz nevi with evidence of epidermal involvement, 56 cases of compound Spitz nevi without evidence of epidermal involvement and 14 cases of dermal Spitz nevi. The epidermal involvement mainly consisted of nesting of nevus cells above the basal cell layer, 9 cases clearly showing evidence of transepidermal elimination of cell nests. Upward spread of single melanocytes (pagetoid spread) was minimal and always associated with nesting or trans-epidermal elimination. The mean age of patients was significantly lower in the group of compound nevi with intraepidermal involvement (7.16 +/- 4.52 years), than in the group of compound nevi without epidermal involvement (13.18 +/- 8.88 years). The age of the latter group was significantly lower than the group of pure intradermal nevi (30.14 +/- 11.25 years). Thus, involvement of the suprabasal epidermis is not a feature of Spitz nevi in adults; in such a case the diagnosis of malignant melanoma should be considered.

The monoethyl ether of hydroquinone (MEH) is known to be a very potent depigmenting agent for skin and hair of black guinea pigs. Its action is due to selective destruction of melanocytes. In order to better understand its pharmacology, MEH was applied or injected into the skin of red and albino guinea pigs, grey DBA-1 mice, black C-57 mice and Syrian golden hamsters. Experimental melanomas S 91, B 16, Asc.M.Mel.1 and V 15 were also treated with this agent. MEH depigmented the brown epidermis of the red guinea pigs; the red hair, however, regrew without any color change. The melanocytes of the albino guinea pigs were not damaged by MEH. The hair of the 2 types of mice treated always became white and the fur of Syrian hamsters lost its black component. The survival time of animals with transplanted melanomas was not increased and gross and microscopic appearance of their melanomas was not altered by intratumoral injections of MEH.

The albinotic skin and hair of 2 patients with Hermansky-Pudlak syndrome were investigated by light and electron microscopy. Incubation of hairbulbs and epidermis in l-dopa revealed a weak tyrosinase activity. The epidermal melanocyte population was of normal density. The most striking feature was the presence of numerous giant melanosomes resembling those mainly reported in various hyperpigmented skin lesions. The association of this melanosomal disorder with the platelet dysfunction and ceroid storage typical of the autosomal recessive Hermansky-Pudlak syndrome might provide new insights into the mechanism leading to formation of giant melanosomes.

The numerical keratinocyte to melanocyte relation was studied in café au lait spots and adjacent normally pigmented skin of 9 patients with classical neurofibromatosis. Compared to normal skin of healthy individuals, the keratinocyte:melanocyte ratio distributions obtained in neurofibromatosis indicated a shift to lower values in the biopsies of café au lait spots and normally pigmented skin. These results are evidence in favor of an impaired tissue organization of the epidermis in neurofibromatosis with regard to the keratinocyte-melanocyte interrelation.

Die Analyse der bei Krankheiten vorkommenden Anderungen der Haarfarbe wird dadurch erschwert, das die biologischen Grundlagen der mit dem Auge erfasbaren reichen Palette von Haarfarben noch ganz ungenugend bekannt sind. Die Komplexitat der die Haarfarbe bestimmenden Faktoren ist erst in den letzten Jahren besser erfast worden.

• An unusual nonfollicular keratinization disorder was observed in a father and his son, and in an unrelated woman. The disorder began during the second decade of life and gradually became more widespread and more pronounced thereafter. The dermatosis is characterized by tiny, rough, keratotic spikes giving the skin a raspy feel on palpation. Microscopically, the lesions showed a thick compact stratum corneum without structural changes in the underlying epidermis except for moderate epidermal cell hyperplasia and some reduction in keratohyalin content. (Arch Dermatol1981;117:412-414)

SINCE 19221 it has been known that in man sunburn and suntan are caused by the action of only a narrow band within the ultraviolet spectrum (λ 290 to 320 mμ). Various methods have been used to prev...

• Background.— Loricrin and involucrin are major precursor proteins to the cornified cell envelope expressed late in epidermal differentiation. Involucrin expression starts in the upper spinous layers in normal human epidermis and precedes loricrin expression, which is restricted to the granular layer. Subsequently, both proteins become cross-linked by the activity of transglutaminases TGK/E as major components of the cornified cell envelope by N e -(γ-glutamyl)lysine isopeptide bonds. In this study, three cases of lamellar ichthyosis were analyzed by immunohistologic study with antibodies to loricrin, involucrin, filaggrin, and transglutaminase TGK. Observations.— A high expression of loricrin and involucrin with a peculiar and abnormal cytoplasmic staining concurred with a diminished cytoplasmic staining of transglutaminase TGK as assessed by antibodies B.C.1 and K.D.3. This pattern was absent in a collodion baby at birth but present 2 weeks later before a phenotype of lamellar ichthyosis appeared clinically. Conclusions.— The results suggest that in our cases of lamellar ichthyosis, (1) disturbed membrane anchorage of transglutaminase TGK could alter loricrin and involucrin cross-linkage and the formation of the cornified cell envelope and that (2) immunohistologic study might serve as an early diagnostic and prognostic tool in the treatment of collodion babies. ( Arch Dermatol. 1993;129:618-624)

Epidermolytic hyperkeratosis is caused by mutations of the differentiation-specific keratins K1 and R10. These mutations produce a weakened cytoskeleton that is prone to collapse resulting in cell fragility and lysis. In this study we have analyzed cultured keratinocytes from EHK patients bearing 10R-to-H and 15L-to-S mutations within the 1A segment of the K10 rod domain. Keratinocytes were grown submerged in serum-free medium and induced to differentiate by growing to confluence and increasing the Ca++ concentration in the medium. Cultures were either harvested for mRNA sequence analysis or subjected to immunofluorescence microscopy. Differentiating keratinocytes from these patients were found to express these K10 mutations in their mRNA. Moreover, these cells could be distinguished from normal kerati- nocytes by their aberrrant morphology. EHK keratinocytes frequently exhibited a collapsed perinuclear network of K1/ K10 filaments and sometimes peripheral granules of K1 and K10 aggregates, reminiscent of the cells of the suprabasal layers in these patients. This report documents the expression of mutant keratin 10 in cultured EHK keratinocytes.

Lamellar ichthyosis is a severe congenital skin disorder characterized by generalized large scales and variable redness. Affected individuals in three families exhibited drastically reduced keratinocyte transglutaminase (TGK) activity. In two of these families, expression of TGK transcripts was diminished or abnormal and no TGK protein was detected. Homozygous or compound heterozygous mutations of the TGK gene were identified in all families. These data suggest that defects in TGK cause lamellar ichthyosis and that intact cross-linkage of cornified cell envelopes is required for epidermal tissue homeostasis.

In Reply.— I agree with Drs Estes and Millman that the patients of Goldstein and Yoon and Gibbs had keratinization disorders similar to what we have recently reported in three cases. Three additional patients in a family of Swiss descent who were living in Argentina were described by Aufgang 1 in 1972. Unfortunately, we missed these reports in our review of the literature. We believe that our cases and those in the literature represent variants of the same entity, which we also characterized by electron microscopy. The clinical manifestation of our cases was different from the others in that our patients complained of a "raspy feel" of the involved skin, caused by the greater number and smaller size of the hard, hyperkeratotic spikes. In the patients described earlier in the literature, the individual lesions were larger and thicker and, therefore, had a flaccid and cosmetically objectionable character.

Experiments with various topically applied compounds have demonstrated that 2-mercaptoethylamine HCI (MEA) and N(2-mercaptoethyl)-dimethylamine HCI (MEDA) are very potent agents that cause depigmentation in treated areas only. When applied to the skin of black guinea pigs, they inhibited melanogenesis, acted selectively on melanocytes, decreased melanocyte density significantly, and rendered the few remaining melanocytes degenerative. In epidermis from MEDA-treated areas, melanocytes could be detected only rarely by electron microscopy. Those that were found contained few melanized melanosomes, many vacuoles, and swollen mitochondria. Depigmentation by any exogenous agent can result from destruction or loss of melanocytes; interference with (1) the biosynthesis of premelanosomes and melanosomes, (2) the conversion of tyrosine to dopa to melanin, (3) the biosynthesis of tyrosinase or the active center of the enzyme, (4) the transfer of melanosomes to keratinocytes; and alteration of the melanin present in melanosomes. Depigmentation by MEDA appears to result from selective destruction or degeneration of melanocytes.