R. Marks

SKIN SURFACE BIOPSY: AN IMPROVED TECHNIQUE FOR THE EXAMINATION OF THE HORNY LAYER

—^The cyanoacrylate adhesives have been used to examine the superficial horny layer in a horizontal plane. The adhesive strips a thin layer of horn from the skin and sticks Jt to glass slides. The preparations are superior to skin surface replicas because of the ease and speed of their production and because of their unfailing clarity. In addition, because actual horn is seen in its in vtvo arrangment, the preparations can be stained histologically and histochemlcally. The results of examination of normal skin and its regional variation, and of viral and seborrhoeic warts, moles, pityriasis versicolor, psoriasis and ichthyosis are reported. The scanning electron microscope has been used to examine the horny squames removed with thivS technique from normal, ichthyotic and psoriatic skins. In psoriatic squames a particularly well developed series of folds and outpouchings of the plasma membrane were noted.

The diagnostic significance of immunoglobulin and fibrin deposition in lichen planus

Direct immunofluorescent (IF) staining was performed on biopsy specimens from fifty‐three patients with active lichen planus. In fifteen of these cases uninvolved skin sites were also examined. Globular or cytoid body‐like deposits of immunoglobulins, mainly IgM, were detected in forty‐six of the active lesions, and in half the uninvolved skin biopsies. The deposition of fibrin in the papillary dermis and around follicular structures was seen only in the active lichen planus papules.

Secondary syphilis: a clinico-pathological review

The histological appearances found in biopsies from fifty‐seven patients with secondary syphilis have been correlated with the clinical morphology of the eruptions. Considerable variation of histological pattern was encountered, and the frequency with which some of the classically described changes were found to be absent or inconspicuous is stressed. Of particular interest were the findings that, in nearly one‐quarter of the biopsies, plasma cell infiltration was either absent or very sparse, and that vascular damage was seen in less than half. Where present, the vessel changes were almost entirely confined to swelling of the endothelial cells. Proliferation of the endothelial cells was most uncommon.

PITYRIASIS LICHENOIDES: A rEAPPRAISAL

Summary.— One hundred and twenty‐eight cases of pityriasis lichenoides presenting at St. Johns Hospital for Diseases of the Skin in the past decade have been reviewed. Sixty of these were seen personally, and 44 of these had lesiuns at the time of interview. Eighteen other patients completed proformata, and adequate hospital records were available for the rest. One hundred and two biopsies from 82 patients with pityriasis lichenoides were also examined in the course of this study. The various clinical manifestations seen in this group of patients has been analysed in order to define the clinical range of the Disease. None of the patients studied developed a cutaneous reticulosis and thus the risk for such an occurrence must be small. Patients with pityriasis lichenoides did not appear prone to any systemic complaint, and the disease seemed to be limited to the skin. Some of the patients who had had the disease for several years developed haemorrhagic and necrotic lesions, suggesting that pityriasis lichenoides varioliformis et acuta and pityriasis lichenoides chronica are variants of a single disease process. Altliough small vessel involvement in the inflammatory process was usual, no histological evidence was obtained to suggest that a vasculitis is of central importance in the pathogenesis of the disease.

RECEPTORS FOR HISTAMINE IN HUMAN SKIN BLOOD VESSELS: A REVIEW

Histamine was one of the first of the drugs occurring naturally in man to be discovered, and it is surprising that even now the pharmacological characterization of such a simple, abundant and ubiquitous amine still remains incomplete. Histamine was first identified by Dale & Laidlaw (1910; 1911) in extracts of ergot. They emphasized its oxytocic actions but also drew attention to its inhibitory properties. The identification of histamine in animal tissues had to await studies of lung and liver extracts by Best, Dale, Dudley & Thorpe (1927) who also highlighted the inhibitory and vasodilator actions of histamine. At about the same time Lewis (1927) adduced considerable indirect evidence that histamine was liberated from human skin following injury and was an important mediator of skin inflammation. However direct evidence of the release of histamine from skin following injury had to await skin perfusion studies (Greaves & Sondergaard 1970; Sondergaard & Greaves, 1971) in which increased amounts of histamine were recovered in perfusates from urticated skin. More recently increased histamine concentrations have been found in venous blood draining cold-challenged skin in cold urticaria (Bentley-Phillips, Black & Greaves, 1976). The frequent failure of conventional antihistamine given systemically to produce reliable suppression of urticarial reactions has led to the suggestion that histamine may be only one of several mediators responsible for the observed vascular changes. However an alternative explanation is now afforded by the discovery of the existence of subclasses of histamine receptors. Ash & Schild (1966) by studying the responses ofa wide range of preparations to analogues of histamine were able to delineate two subclasses of receptors. Subsequent work by Black et al. (1972) defined H|-receptors which were involved in actions of histamine antagonized by conventional (H,) antihistamines and H, receptors which were unaffected by H,-antihistamines, but were antagonized by burimamide which was thus defined as an H2-receptor antagonist. Actions of histamine involving Hj-receptors include stimulation of gastric acid secretions, the chronotropic action of histamine on the heart and inhibition of contraction of the rat uterus The possibility that further subclasses of histamine receptors exist has not been excluded. Exploration of the possibility that human skin blood vessels possess both classes of receptor was prompted hy the observation that the vascular flushing in skin of human volunteers who had received histamine intravenously could be suppressed by administration of H2-receptor antagonists (Wyllie, Hesselbo & Black, 1972; Burland et ah, 1975) and by the identification of two synthetic analogues of histamine, 2-methyl histamine and 4-methyl histamine with predominantly H,-agonist and Hiagonist activity respectively (Black et al., 1972). 2-Methyl histamine evokes a weal and a bright red surrounding fiare due at least in part to an axon refiex. 4-Methyl histamine also causes a weal but the surrounding erythema is less bright and does not involve an axon reflex. The magnitude of the erythema response, but not the weal, is dose-related for each drug. Itching and pain are variable and occur in response to both compounds (Robertson & Greaves, 1977). These observations suggest that the axon refiex and vasodilator actions of histamine are predominantly due to H, and H2 receptors respectively. The actions of chlorpheniramine, an H,-antihistamine, and cimetidine, a highly selective Hiantihistamine (Brimblecombe et al, 1975), on erythema and wealing due to three doses of both agonists are of great interest (Figs i and 2). Chlorpheniramine inhibited erythema due to 2-methyl histamine but cimetidine had no effect on this reaction. By contrast the erythema reaction due to 4-

Epidermal cell kinetics in lichen planus

The epidermis in lichen planus presents an apparently paradoxical situation. There are on the one hand epidermal hypertrophy acanthosis and hypergranulosis, and on the other, destruction of the generative compartment with erosion of the basal layer. In order to understand how the two processes can co‐exist, thirty‐five lichen planus papules from twenty‐five patients were injected intracutaneously with IO μ Ci of tritiated thymidine. Sixteen of these lesions were removed after 50‐60 min and nineteen were removed after longer intervals of up to 10 days. Autoradiographs prepared from biopsied lesions demonstrated that keratinocytes had migrated into the lichen planus lesion from the intact margins, replaced the eroded basal layer and repopulated the epidermis of the lesion. It is concluded that the changes observed in the epidermis seen in lichen planus can be interpreted as the result of a continuous process of (1) erosion and (2) repopulation in an attempt at healing of the wounded area.

Sclerosing epithelial hamartoma.

The clinical aspects and histological details of sixteen examples of an epithelial hamartoma are reported. Similar cases have previously been described as solitary trichoepithelioma. However, the histological features are distinct and warrant a separate designation. The importance of histological differential diagnosis is emphasized.

Trimethylaminuria: the use of choline as an aid to diagnosis

Trimethylamine metabolism can be studied by means of choline loading. The value and some limitations of the method are illustrated by results obtained in normal subjects, a patient with the Fish Odour syndrome and his kindred.

Active epidermal movement in human skin in vitro

Epidermal cells migrate from the edges of adult human skin in culture during the first 48 h. In order to determine whether mitotic acitivity was responsible for this cell movement the autoradiographic labelling index for cells in DNA synthesis was determined for skin at different stages of culture. The labelling index of skin maintained for 48 h but labelled with tritiated thymidine in the first 4 h, did not differ significantly from skin both maintained and labelled for 4 h only. Skin maintained for 48 h but labelled in the last 4 h showed a much lower labelling index. No normal mitotic figures were seen in the epidermis of skin maintained for 48 h but exposed to colcemid for the last 4 h of culture.

FIBROUS PAEULP OF THE NOSE

SUMMARY.— A study has been made of 34 cases of fibrous papule of the nose presenting at St Johns Hospital for Diseases of the Skin in the past decade, Histological sections from biopsies of these lesions were examined and compared with lesions of juvenile melanoma and naevus cell naevus arising on the face. In 2 patients fibrous papules were investigated by enzyme histochemical methods. Fibrous papules were usually single small nodules on the nose, often simulating angiomata, moles or pyogenic granulomata. The sexes were equally affected and most of the patients were in the third to the fifth decades. Although these lesions were not distinctive clinically, histologically they presented a characteristic appearance, which included a distinctive fibro‐vascular component composed of broad bands of connective tissue orientated at right angles to the surface and interspersed with multinucleate cells and undoubted naevus cells, and an increased number of epidermal clear cells.