Biomedical subjects
Publications and source records attributed to H Tagami.
We describe a 19-year-old Japanese man with severe extensive necrotizing fasciitis that started as Fournier's gangrene to involve the external genitalia, thigh and lower abdomen. High creatine phosphokinase, transient immunosuppression (reduced serum IgG level and negative tuberculin skin test reaction) and disseminated intravascular coagulation occurred during the necrotizing fasciitis.
Contact sensitivity and immediate hypersensitivity to extracts from Pityrosporum ovale were studied in patients with atopic dermatitis (AD). In a chamber-scarification patch test, 75 (64%) of 118 patients with AD responded positively, compared with 1 (3%) of 35 healthy volunteers. However, no significant statistical correlations were found between contact sensitivity to P ovale in patients with AD and any of the following factors: age, sex, distribution of skin lesions, presence of pruriginous papules, history of infantile seborrheic dermatitis, or concomitance of other atopic diseases. Lymphocyte transformation test with P ovale antigen confirmed that those with positive patch test reactions showed significantly high stimulation indexes. The antigenic substances divided by gel filtration high-performance liquid chromatography were found in a fraction of components with molecular weights above 60 kd. In addition, 25 (71%) of 35 patients with AD showed a positive immediate response to P ovale extract in a prick test, whereas none of 11 healthy volunteers showed any response. Although the incidence of the positive immediate responses was similar to that in contact sensitivity, there was no clear correlation between the delayed and immediate hypersensitivity reactions. Based on these results, we think that P ovale plays a role as an allergen derived from the host environment in the exacerbation of the skin lesions of AD.
Subungual melanomas are one of the most common types of malignant melanoma among the Japanese population. Although most pigmented nail streaks are benign and remain unchanged in their color and shape for a long time, rarely are they precursor lesions of subungual melanomas i.e., a rapid growing pigmented nail streak resulting in diffuse melanosis of the nail is thought to be an early stage of subungual melanoma in situ. We found four patients with these changes: three of these patients were children. The lesions occurred on the right index finger, right thumb, left middle finger, and right great toe, respectively. A slightly haphazard combination of colors ranging from dark brown to black, the important characteristic of subungual melanoma in situ, was observed in two cases. In the remaining two cases, although the haphazard combination of colors was not distinctive, many fine, dark longitudinal lines were seen within diffuse, light-brownish pigmentation. Serial histologic examination of the excised tissue specimens showed great proliferation of vacuolated melanocytes with variable nuclear atypicality along the entire basal layer in all cases. These histologic changes were compatible with those of atypical melanocytic hyperplasia or intraepidermal melanoma (in situ melanoma), which is an early lesion of subungual melanoma. An adult case is thought to be a definite example of a subungual melanoma in situ. We also made the diagnosis of melanoma in situ in the remaining three cases of children with rapidly growing pigmented nail streaks because their histopathologic features were distinguishable from those of the adult case. However, there remains some hesitation about this because invasive subungual melanoma is rare in children.
Tyrosinase-negative oculocutaneous albinism (OCA) is an inborn error of metabolism, characterized by a complete lack of melanin pigments in the eyes and skin. We have isolated and characterized the tyrosinase gene of one affected child (S.S.) with tyrosinase-negative OCA. Sequence analysis reveals a single-base insertion in the exon 2 that shifts the reading frame and introduces a premature termination signal (TGA codon) after the amino acid residue 298. Functional analysis of the mutated gene indicates that such a truncated tyrosinase lacking one potential copper-binding region is catalytically inactive. We therefore conclude that the albino phenotype of the patient S.S. is a consequence of the inactive tyrosinase caused by the nonsense mutation in the tyrosinase gene.
The DNA segment harboring the promoter region and the exon 1 of the human tyrosinase gene has been cloned and characterized. Sequence analysis reveals the amino-terminal half of tyrosinase molecule including a signal peptide, of which six amino acid residues are not represented in the tyrosinase cDNA, pHT gamma 1 [Shibahara et al. (1988) Tohoku J. Exp. Med. 156, 403-414]. We therefore constructed the expression plasmid containing the human tyrosinase precursor cDNA, and introduced it into mouse amelanotic melanoma cells. Both tyrosine hydroxylase and dopa oxidase activities were expressed only in the cells transfected with such a full-length cDNA, providing direct evidence that tyrosinase actually possesses a dual catalytic activity.
We have examined the effects of four well-characterized cytokines with T lymphocyte-stimulatory activity, i.e., interleukin (IL)-2, IL-3, IL-4, and granulocyte-macrophage colony-stimulating factor (GM-CSF) on [3H]-thymidine incorporation in peripheral blood mononuclear cells (PBMs) obtained from patients with psoriasis. Under the influence of these cytokines, the incorporation of [3H]-thymidine into the PBMs was not different between psoriatic patients and healthy controls either in culture supplemented with pooled AB serum or with autologous serum. However, a potent immunopotentiator OK-432, which is a lyophilized preparation of penicillin-treated low virulence Su-strain of Streptococcus pyogenes group A3, induced significantly less incorporation of [3H]-thymidine into the PBMs from psoriatic patients than those from healthy controls [in both the culture supplemented with pooled AB serum (p less than 0.01) and that with autologous serum (p less than 0.01)]. This reduction in thymidine uptake was closely related to the disease activity as well as to the extent of skin lesions of the psoriatic patients. The defective immune response of PBMs from psoriatic patients to OK-432 probably reflects an abnormality at the level of interaction between monocytes and T cells or at the subsequent production and release of cytokines by them.
We investigated in vitro the contents of epidermal cysts for complement activation and found that they activated complement mainly through the alternative pathway. Chemotactic C5a anaphylatoxin produced by the cyst contents after contact with serum most likely plays a significant role in the initiation and aggravation of inflammation in ruptured epidermal cysts. Our additional study disclosed that components of three representative follicular resident microorganisms (Pityrosporum ovale, Propionibacterium acnes, and Staphylococcus epidermidis) also produced C5a anaphylatoxin mainly through the alternative pathway; the C5a production was more vigorous than that by a virulent pathogen, Staphylococcus aureus. These results suggest that accidental colonization of the cyst contents by these follicular microbial flora further augments the inflammatory changes in ruptured epidermal cysts.
Tumor necrosis factor (TNF)-alpha is a cytokine with multiple biological properties, particularly proinflammatory, apart from the induction of tumor necrosis. In order to elucidate the role of TNF-alpha in the pathogenesis of psoriasis, we have carried out bioassay and enzyme-linked immunosorbent assay for TNF-alpha in suction blister fluids and horny tissue extracts from psoriatic skin. Although bioassay showed some activities in the suction blister fluids and horny tissue extracts, there were no significant differences between the levels of activities from normal and psoriatic skin. They were at the background level and pretreatment of the samples with anti-TNF-alpha antiserum failed to abrogate the activities. ELISA confirmed the absence of TNF-alpha. Therefore, the present study could not verify that TNF-alpha plays a major role in the pathogenesis of psoriasis.
In contrast to scales collected from the scalps of nine healthy individuals where a few parakeratotic cells are observable, a large number of parakeratotic cells associated with some infiltrated polymorphonuclear leukocytes (PMNLs) were found in the scales obtained from 11 individuals complaining of dandruff. Therefore, we determined the neutrophil chemotactic properties of the water-soluble extracts of dandruff scales and normal control scalp scales. Aqeous extracts fractionated by Sephadex G-75 showed a potent chemotactic activity only in the fractions of the dandruff patients that eluted with cytochrome C marker (cyt C; molecular weight, 12 kDa). It was comparatively stable to heat but was greatly inhibited by the addition of anti-C5 antiserum. Radioimmunoassay demonstrated that, although small amounts of C5a and C4a anaphylatoxins were demonstratable even in the extracts of normal scalp, they were found in significantly increased amounts in the extracts of dandruff. Moreover, there was a significantly positive correlation between C5a and C4a concentrations in these extracts. These results suggest that classical complement pathway activation with resultant production of C5a anaphylatoxin is involved in the migration of PMNLs into the lesional skin of dandruff.
The peptide fractions containing C5a des arg and anionic neutrophil activating peptide (ANAP) and the low-molecular-weight fractions containing LTB4 in psoriatic scale extracts exert a potent polymorphonuclear leukocyte (PMN) chemotactic activity. To evaluate whether any of these components in the psoriatic scale extracts stimulate a respiratory burst in PMNs, we studied luminol-dependent chemiluminescence (CL) in PMNs under their direct stimulation. After fractionation by molecular sieve chromatography, pooled peptide fractions eluting near the cytochrome c marker from eight samples induced high CL in PMNs, whereas those eluted in low-molecular-weight fractions after vitamin B12 marker were very weak in this response. Moreover, in six samples such low-molecular-weight fractions eluting near the vitamin B12 marker were found to have a suppressive effect on the oxidative metabolism of neutrophils induced by other stimulators. These findings suggest that the fraction of chemotactic peptides in psoriatic scales plays a major role in the activation of PMNs, inducing tissue damage in the psoriatic lesional epidermis. On the other hand, at least some low-molecular-weight components in psoriatic scales seem to exert an inhibitory effect on the respiratory burst induced by other activators.
Multicentric reticulohistiocytosis affecting a 13-year-old boy induced a sclerosing change of the leg. The cellular infiltrate comprising activated T lymphocytes and macrophages and human lymphocyte antigen (HLA)-DR expression by keratinocytes in lesional skin all suggest the involvement of cellular immune reactions. We administered systemic cyclosporine but could not obtain a favorable effect without a concomitant low dosage of prednisone.
The involvement of cellular immune reactions in the pathogenesis of many inflammatory dermatoses can be postulated from their histopathologic features, e.g., those dermatoses that show a perivascular lymphohistiocytic infiltration in the dermis in addition to their own characteristic epidermal changes. Several granulomatous dermatoses further show an additional infiltration of epithelioid cells. However, experimental production of similar changes is usually not feasible in animals. A human model is needed of delayed-hypersensitivity skin reaction induced by a definite antigen. After closely observing the histopathologic changes of the skin reactions to the purified protein derivative (PPD) of tuberculin, we noted that all patients did not show uniform histologic patterns at intradermal PPD injection sites. Therefore, we have tentatively analyzed histopathologically the pattern of tuberculin skin reactions at injection sites 48 h to 1 year after injection in eight healthy volunteers and 63 patients with various dermatoses. We classified the reactions at 48 h into three types, based on the extent of the tissue damage (i.e., their resemblance to features noted in corresponding inflammatory dermatoses): (a) the perivascular dermatitis type, (b) the basal spongiotic dermatitis type, and (c) the erythema multiforme type. There was a clear correlation between the magnitude of macroscopic skin reactions and these histopathologic patterns. Even those with clinically negative reactions showed a reaction pattern of perivascular dermatitis, whereas those who clinically developed prominent inflammatory reactions with blister formation always showed a erythema multiforme-like histologic pattern. Interestingly, in more than half of the cases, the dermal cellular infiltrate had a mixture of various numbers of neutrophils in addition to mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Anti-DNA autoantibodies are known to cross-react with a wide variety of substances including cell-surface molecules. Thus, we examined cross-reactivities of 20 murine monoclonal anti-DNA antibodies with normal human and mouse skin tissues. Hybridomas producing these monoclonal antibodies were established from non-immunized spleen cells from autoimmune MRL-lpr/lpr mice, a strain characterized by spontaneous development of SLE-like disorders including skin changes. They were selected based on their reactivity to DNA in a typical enzyme-linked immunosorbent assay, in which nine monoclonal antibodies were reactive with both double-stranded DNA and single-stranded DNA, whereas nine monoclonals were reactive only with single-stranded DNA. Even though only seven of them were observed to stain nuclei, most of the monoclonal antibodies revealed strong and distinct cross-reactivities to various components of the skin tissues including the epidermal basement membrane, keratinocytes at different locations of the epidermis, melanocytes, Langerhans cells, Thy-1+ dendritic cells in the case of murine skin, and mast cells. Our results suggest a possible role of so-called anti-DNA antibodies with high or low affinities to DNA in the pathogenesis of cutaneous lesions of lupus erythematosus.
Because of its efficient water-holding capacity, healthy stratum corneum (SC) can stay soft and flexible under any environmental conditions. There may be, however, a great difference in water content within the SC between the lowermost layer that faces the wet underlying living tissue and the superficial portion of the SC that is exposed to the relatively dry ambient atmosphere. To better understand the water profile of the SC and also to verify the accuracy of measurements of high frequency conductance used to evaluate the hydration state of the skin surface, we devised a simple and convenient in vitro model of the SC that stimulates the in vivo setting of the SC. It consists of an isolated sheet of SC whose lower surface covers a pad of water-saturated filter paper, and its upper surface is exposed to the ambient atmosphere. By placing this model in environments with different relative humidities (RH), we confirmed that the recorded conductance values correlated well with the actual water content of the SC (r = 0.94). Using a model having five layers of SC sheets, the water content of the innermost portion of the SC was estimated to be equivalent to about 90% of its dry weight; this level of water content remaining relatively constant over a wide range of ambient RH except in extraordinarily humid environments above 90% RH when water began to accumulate excessively in the whole SC. Using this five SC-sheet model, it was clearly demonstrated that there was an almost straight water concentration gradient from the lowermost layer to the uppermost layer of the SC. We also confirmed that the skin conductance of the high frequency current correlated well with the water content of the superficial portion of the SC as well as with that of the whole SC, therefore, it is a good parameter of the hydration state of the superficial layer of the SC.
We provide evidence that stratum corneum (SC) activates complement through the alternative pathway to generate C5a anaphylatoxin. By immunofluorescence studies it was shown that in addition to circulating IgG autoantibody, there were anti-SC antibodies of IgM and IgA classes in the sera from normal individuals. However, all the titers were significantly lower than the level of C3 deposition between corneocytes. By contrast, no C1q deposition occurred. Immunoelectrophoretically the orthokeratotic SC homogenates were found to induce the conversion of C3 from native C3 to C3b in fresh human serum even when the classic pathway was blocked by Ca2+-chelation. Enzyme immunoassay showed that factor B split product, Bb, was generated by the SC homogenates in the Ca2+-chelated serum. Radioimmunoassay for C5a also demonstrated that the SC homogenates could generate C5a anaphylatoxin in serum to an extent similar to that in non-treated serum when restricted to the alternative pathway activation; neutrophil chemotactic activity was generated in Ca2+-chelated serum at levels comparable to that generated in non-treated fresh serum. We separated the SC samples into a cornified envelope and soluble and keratin fractions. The cornified envelope was more effective in activating complement. This activity resided in heat-stable and non-lipid substances of corneocytes. Our hypothesis is that when the SC comes in contact with serum, it activates complement mainly through the alternative pathway to induce chemotactic C5a anaphylatoxin. Hence, inflammation in normal individuals after a traumatic injury to the skin or rupture of acne comedones, or epidermal cysts and possibly the formation of subcorneal sterile pustules noted in several dermatoses are explainable through this mechanism.
A patient with malignant lymphoma repeatedly developed transient rosacea-like dermatitis several days after each interruption of continuous oral prednisone intake. We thought that the eruption was provoked by withdrawal of orally administered steroid, and thus we diagnosed the patient as having steroid-withdrawal rosacea-like dermatitis, one manifestation of steroid-withdrawal syndrome.
The relationship between clinical severity, the hydration state of the skin surface as assessed by a conductance with a 3.5 MHz high frequency impedance meter, and the amino acid content of the stratum corneum (SC) of six patients with ichthyosis vulgaris and 30 elderly persons with varying degrees of xerosis was investigated. With an increase in the severity of xerosis the SC showed a decrease in hydration and in its extractable amino acid content. There was a significant correlation between the hydration state and amino acid content of the SC. Although there was a significant correlation between the amino acid content of the lower leg SC and that of the forearm SC in the same subject, the former was generally lower, corresponding to the greater incidence of xerosis on the lower leg. These results suggest that a decreased amount of amino acids may be the result of low profilaggrin biosynthesis in the epidermis and that this is involved in the pathogenesis of these xerotic skin conditions. Clinical improvement of the xerosis following treatment with a urea-containing cream was not accompanied by any significant change in the amino acid content of the SC.
White dermographism constitutes an abnormal vascular reaction characteristically demonstrable in atopic dermatitis; however, there is no information about it in the infantile phase of atopic dermatitis. Therefore we examined 73 infants younger than 3 years of age with eczematous dermatitis for the demonstrability of white dermographism after mechanical stroking of the lesional skin. None of the 40 healthy control infants showed white dermographism on their normal skin. In contrast, an age-dependent increase was demonstrated in patients with infantile eczema, from 11% in those 1 to 2 months of age to 85% in those older than 7 months. There was no correlation between the demonstrability of white dermographism in early infancy and the prognosis of infantile eczema. Based on our study of various types of dermatitis experimentally induced in adult volunteers, we think that, in addition to the immaturity of infantile skin, the presence of acute dermatitic changes may be related to inability to demonstrate white dermographism in the early phase of infantile eczema.