Biomedical subjects
Publications and source records attributed to C Pierard-Franchimont.
A 4 year-old boy presented an acute pruriginous dermatitis of the hands, forearms and abdomen. A skin surface biopsy revealed numerous trichomes, small prickles present on plants. These trichomes were those of prickly pears and stuck deeply in the skin, inducing an inflammatory reaction known as Sabra dermatitis. A number of plant dermatitides are due to the presence of trichomes such as those due to linden, primula, wild rose or nettle.
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Photochemotherapy induces alterations in the skin that resemble those in xeroderma pigmentosum. Acute responses may be distinguished from late, chronic, and delayed responses to PUVA. All of the types of cells present in the skin are affected by photochemotherapy. The structure of the epidermis and of the superficial dermis are altered and, possibly as a consequence, neoplasms may ensue.
Replication of Paget cells in mammary and extramammary Paget's disease was evaluated by autoradiography after incorporation of tritiated thymidine. Neoplastic cells proliferated in the deepest layers of the epidermis suggesting a topographical control of their multiplication similar to that of the normal epidermis.
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Cylindromas of the skin are subjected to a constant biological evolution in their growth and differentiation, leading in rare instances to metaplasia or even in true malignancy. By using optical microscopy and autohistoradiography after incorporation of tritiated thymidine and proline, several stages of neoplastic progression can be recognized such as growth, primary involution, inflammatory regression and malignant transformation. The stage of growth is characterized by low proliferative indices in clear cells of the lobules while dark cells are almost not dividing. Primary involution consists of massive accumulation of basement membrane components accompanied by lysis of cells. Inflammatory regression results from the infiltration of the neoplasm by lymphocytes with disappearance of the basement membrane. Malignant transformation appears to be multifocal.
We report the observation of 16 cases of cutaneous T cell lymphoma consisting of 11 cases with mycosis fungoides and 5 cases with high-grade malignant lymphomas. A standardized clinical evaluation is proposed for patients with low-grade malignant lymphomas for whom we favor the use of non-aggressive therapeutic regimens. High-grade lymphomas need a more complete systemic exploration. Treatment of cutaneous T cell lymphomas should be started with the least aggressive antineoplastic therapy.
The proliferative rates of cells of malignant melanomas were studied by autoradiography after incorporation of tritiated thymidine in them. There is a relationship between the proportion of melanomatous cells synthesizing DNA and the maximum thickness of the neoplasm. Our data suggest that there are two biologically distinct steps in the evolution of malignant melanoma that are closely related to the direction of growth of the neoplasm (horizontal or vertical) but unrelated to the clinicopathological pattern (superficial spreading, nodular or lentiginous). Malignant melanomas with high risk for early metastases are characterized by higher labeling indices for tritiated thymidine (greater than 1.5%) and by greater numbers of melanomatous cells synthesizing DNA (greater than 40/mm2 at the lateral margins of the neoplasms).
The spontaneous evolution of molluscum contagiosum was studied on autoradiograms after incorporation of tritiated thymidine. Three patterns of distribution and intensity of labeling were distinguished and interpreted as three successive stages in the evolution of the lesions, corresponding to growth, steady-state, and regression. The association of an inflammatory cell infiltrate with the traumatic disruption of the infected epithelium may occur during any of the three stages. It is concluded that spontaneous regression of molluscum contagiosum may depend upon two distinct mechanisms that belong to spontaneous noninflammatory and traumatic-inflammatory processes.
Impetigo herpetiformis and pustular psoriasis during pregnancy are distinct diseases. Pustular psoriasis during pregnancy is indistinguishable clinically, genetically, and histologically from pustular psoriasis in women who are not pregnant. Impetigo herpetiformis is not a heritable disorder and is not found particularly in persons with a personal or family history of psoriasis. Histologically in impetigo herpetiformis there are many large mononuclear cells in the dermis and in epidermal pustules. Proliferation of these mononuclear cells in the dermis is intense.
Suprabasal acantholysis, a common feature of several inflammatory skin diseases, develops exclusively within the germinative cellular pool of the epidermis. The process induces repair mechanisms by proliferation of cells in the suprabasal layers in whatever conditions it occurs, except in pemphigus vulgaris. Dyskeratotic acantholytic cells do not synthesize histidine-rich keratohyaline. Acantholysis with dyskeratosis is a peculiar type of death that affects cells that are probably engaged principally in proliferation.
Pseudolymphomas and malignant lymphomas may be distinguished on the basis of their proliferative activities, evaluated by radioautography after incorporation of tritiated thymidine. In malignant lymphomas, cells synthesizing DNA are numerous and are distributed regularly in the infiltrate. In pseudolymphomas many atypical cells do not synthesize DNA, and those labelled with [3H]TdR are often grouped in restricted areas of the infiltrate.
The Ehlers-Danlos syndrome is commonly divided into at least 8 types according to clinical, genetic, and biochemical aspects. We propose histological criteria that would permit a more precise diagnosis of the gravis and mitis types. In the gravis type, collagen bundles are thin and rare in the dermis and hypodermal septae; in polarized light, they are less refringent than in normal skin. This is associated with an increase in the relative proportion of elastic fibers. In the mitis type, the looseness of the collagen network is much less evident; elastic fibers are not in excess but irregular in size, shape, distribution, and orientation.
4 patients suffering from generalized pustular psoriasis, von Zumbusch type, were treated with the aromatic retinoid Ro-10-9359. Lesions were completely cleared after 4 weeks of therapy. A maintenance dose was usually required to prevent relapses. Side-effects were often observed but always remained very mild. Ro-10-9359 represents the best available treatment for generalized pustular psoriasis.
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The resistance to traction of the dermo-epidermal junction and of the superficial vascular plexus is altered by oral photochemotherapy. The dermo-epidermal junction is weakened when the resistance of vascular walls increases. These modifications are related to the histological alterations occurring during photosclerosis induced by PUVA.
Formation of hyperplastic dermal papillae in psoriasis was studied by radioautography after incorporation of tritiated thymidine, by planimetry and by scanning electron microscopy. At the border zone of a psoriatic plaque, hyperplastic dermal papillae result from a passive lengthening of dermal papillae. At the center of a psoriatic plaque, papillomatosis represents an active remodelling of the papillary dermis with destructions and neoformation of the basement membrane zone. The origin of these remodellings is presumably mechanical and related to forces exerted by the epidermis.
Intradermal (i.d.) tests with phytohemagglutinin (PHA) and tuberculin are used in clinical practice to evaluate the cell-mediated immunity. The biologic significance of the skin response to PHA, clinically evaluated by the extent of erythema and induration, was studied histologically after incorporation of tritiated thymidine. It was compared to tuberculin tests. The rate of recruitment and the respective amount of inflammatory cells varied between patients and in time. In PHA tests the inflammatory reaction occurred in two phases, the first one consisting in the predominance of polymorphonuclears, the second one being characterized by chemotactism of lymphoblasts many of which synthesized DNA. The "in vivo" reaction to PHA is therefore complex; the same clinical evaluation corresponds to markedly different stages and events in the biological reaction. The histological grading of the PHA test is therefore desirable in the evaluation of the cell-mediated immunity because only the blastic proliferation is of importance in its rating and not the edema and the accumulation of polymorphonuclears.