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Biomedical subjects

C M Lapiere

Publications and source records attributed to C M Lapiere.

At least 55 records · Page 3Linked to original sources
PubMed1982

Significant progress in dermatologic research since 1977.

Some active fields of experiment dermatology have been selected to demonstrate the interaction between basic research and clinical dermatology. The identification of the Langerhans cell, the typing of mononuclear cells, and the identification of T cell growth factors have significant implication in contact dermatitis, lymphomas, etc. The group of papovaviruses is better defined in relationship to the type of disease that they produce and its oncogenic potential. Various types of vasculitis are better understood, thanks to research in humoral immunity and complement activation. Melanogenesis and its control by peptides is progressing. New specific proteins have been identified in the connective tissues, and their role has been clarified. Identification of specific proteins of keratinocytes and study of differentiation of these cells have provided useful information and some skin disorders. The control of epidermal cell proliferation and differentiation, through membrane receptors, growth factors, and intracellular enzymes, is progressively giving clues to the understanding of genetic disorders, cancers, the effect of retinoids and phototherapy.

Complement Activation↗
PubMed1982

Proliferation of the characteristic histiocyte of histiocytosis X in the skin.

The proliferation of the characteristic histiocyte of histiocytosis X in the skin of a patient with localized lesions of Hand-Schüller-Christian disease has been studied by counting cells in mitosis and cells that incorporated tritiated thymidine. The mitotic index was very low although about one-quarter of the cells were synthesizing DNA. In the deep dermis, many eosinophils were associated with a decreased tendency of the characteristic cells to synthesize DNA. We conclude that in this patient with a localized type of histiocytosis X, the characteristic cells are stimulated to enter the S phase when they are situated close to the epidermis, but there is no evidence that they divide in the skin subsequently.

Adult↗
PubMed1982

Angioplastic necrolytic migratory erythema. Unique association of necrolytic migratory erythema, extensive angioplasia, and high molecular weight glucagon-like polypeptide.

A diabetic patient developed necrolytic migratory erythema with extensive angioplasia and high molecular weight glucagon-like polypeptide. There was no associated neoplasm such as glucagonoma. Lesions in the skin were studied by standard optical microscopy and by radioautography after incorporation of tritiated thymidine. Alterations in the skin begin as focal necrosis in the epidermis and in epithelial structures of adnexa, followed by marked angioplasia and a superficial and deep perivascular dermatitis.

Adult↗
PubMed1982

Actinic granulomas and relapsing polychondritis.

A patient developed concomitantly chondritis of the two auricles, diffuse cutaneous vasculitis and actinic granulomas. Alterations in skin and cartilage were prominent in the elastic tissue. Anticollagen type II antibodies were absent from the serum and there was no deposit of immunoreactants in cartilages. In this form of relapsing polychondritis, the pathomechanism resembles that of diffuse actinic arteritis as proposed by O'Brien. It is concluded that relapsing polychondritis may represent a heterogeneous syndrome with regard to its pathogenesis.

Biopsy↗
PubMed1980

Follicular lymphomatoid papulosis.

In two patients who episodically developed eruptions of papules and nodules for many years, the lesions developed at the sites of hair follicles or around ruptured follicular cysts. They were pseudomalignant lymphomas in histologic appearance and benign in biologic behavior. From its limitation largely to follicular adnexa, the condition appears to be a distinct type of lymphomatoid papulosis.

Adult↗
PubMed1979

Phenytoin dependent fibrosis in polyfibromatosis syndrome.

We have followed up the evolution of a polyfibromatosis syndrome in a 20-year-old male treated with diphenylhydantoin for epileptic convulsions. The main symptoms were attributable to fibrosis of the adventitial dermis associated with camptodactyly, knuckle pads, tendinous calcification, osseous hypoplasia of the face, scoliosis with thoracic deformation, and osteolytic changes of wrists, hands and feet. Quantitative variations of the mechanical properties of skin measured in vivo suggested a reversible fibrosing action of diphenylhydantoïn in a genetically predisposed patient.

Adult↗
PubMed1979

Cell proliferation in a malignant angioendothelioma during sequential chemotherapy.

The rate of cellular proliferation was studied in the neoplastic cells of a malignant angioendothelioma and in its inflammatory infiltrate by means of optical radioautography after incorporation ex vivo of tritiated thymidine. One third of the normal looking, as well as the atypical, endothelial cells were engaged in the cell cycle of proliferation. This large pool has been effectively suppressed during subsequent chemotherapy which resulted in partial regression of the neoplasm. The proliferative activity of the infiltrate was higher inside the neoplasm than at its periphery.

Aged↗
PubMed1978

The relationship between blood pressure and aortic collagen metabolism in renal hypertensive rats.

1. Biosynthesis and deposition of collagen, as well as DNA and total proteins, are increased in aortae of rats after 1, 3 and 6 weeks of hypertension. 2. The maximal increase in the rate of synthesis of collagen is observed within one week of hypertension when the stress to the arterial wall is maximal. 3. Reserpine administration prevents hypertension and inhibits the increase of collagen metabolism. 4. At any time of evolution of the hypertension, a linear positive correlation is found between the collagen content in the aorta and the level of blood pressure. 5. These data suggest that synthesis of matrix components by the arterial smooth-muscle cells is controlled by variation in the blood pressure level and is not a direct consequence of circulating humoral factors liberated by the ischaemic kidney.

Animals↗
PubMed1977

Interaction between collagen type I and type III in conditioning bundles organization.

Type I and type III collagen extracted from skin was purified by differential salt precipitation and chromatography. By heating to 37 degrees, type I formed after a lag phase a floppy and opalescent gel of high optical density and type III formed more rapidly a translucent and rigid gel of low optical density. Addition of type III to type I resulted in formation of gels of reduced optical density and lag phase related to the proportion of type III added. Phase contrast and scanning electronmicroscopy demonstrated the formation of thick bundles of type I, thin fibers of type III and bundles of intermediate size related to the proportion of type III. The relationship between collagen type and bundle architecture might prove most significant in conditioning the mechanical properties of the connective tissues in normal and pathological conditions.

Amino Acids↗
PubMed1975

Type III procollagen and collagen in skin.

A form of collagen, containing three alpha chains of type III, can be extracted from foetal calf, calf and rat skin under physiological conditions. This native collagen was purified by DEAE-cellulose chromatography and then was analysed by polyacrylamide gel electrophoresis which showed it consisted of several high molecular weight components, the size of gamma components and larger species. Prior reduction in dithiothreitol dissociated these large polymers into two components: the minor one migrated between the alpha1 (I) and alpha2 chains while the predominant one migrated between the alpha and beta chains. These two monomers were isolated by CM-cellulose chromatography. The minor one, which eluted between the alpha1 and alpha2 chains, had a molecular weight of approx. 95 000; its amino acid composition was similar to that of alpha1(III). The major one eluted in the alpha1 region and had a molecular weight of approx. 120 000; its amino acid composition, while similar to that of the alpha1(III) chain, differed in detail, and it is presumed to be a pro-alpha1(III) chain. Following pepsin digestion, the native collagen remained as a disulfide-bonded trimer which dissociated into only one component, a1(III), when denatured in dithiothreitol. These results suggest that the original, extracted protein consisted primarily ofa precursor form of type III collagen. This procollagen did not polymerize when heated at 37 degrees C and did not form the usual segment long spacing aggregates under suitable conditions. It was not modified by incubation with a purified procollagen peptidase preparation. This appears to be the first example of the isolation of type III (pro)collagen by extractive methods, without resorting to tissue digestion by proteolytic enzymes.

Amino Acids↗
PubMed1975

[Influence of x-rays on depolymerization of lathyric collagen fibers reconstituted in vitro].

Irradiation of native collagen from lathyric rats in solution reduces the depolymerisation speed in the cold of fibres formed by gelification at 37 degrees C, rendering it thus comparable to the speed observed with normal collagen. In our test this normalisation does not appear if the collagen is irradiated in the state of gel. These observations and the absence of specific modifications induced by irradiation in the presence of reagents of the aldehydes speak in favour of the interference, on irradiation, of chemical groups different from the physiological aldehyde groups.

Aminopropionitrile↗