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Biomedical subjects

R Laurent

Publications and source records attributed to R Laurent.

At least 127 records · Page 7Linked to original sources
PubMed1981

An improved method for sacro-iliac joint imaging: a study of normal subjects, patients with sacro-iliitis and patients with low back pain.

A new method is described for quantitative measurement of the uptake of 99mTc--methylene diphosphonate (MDP) by the sacro-iliac joints. The method uses 'regions of interest' providing advantages over the previously described 'slice' method; the two methods are compared in normal subjects, patients with known sacro-iliitis and patients with low back pain. Sacro-iliac activity, as calculated by the sacro-iliac index (SII) in normal patients, was shown to decrease with age in females but not in males. The SII was compared with radiographs of the sacro-iliac joints in the patients with known sacro-iliac joint disease and in those with low back pain. The method is useful for the exclusion of sacro-iliitis as a specific cause of back pain.

Adolescent↗
PubMed1981

Synovial histopathology of behçet's syndrome.

Synovial tissue obtained from 7 patients with Behçet's syndrome and 7 patients with early rheumatoid arthritis could not be distinguished under ordinary light microscopy when examined blind. A wide spectrum of features was seen in both diseases, and it is suggested that these may reflect severity and duration as much as the nature of the arthritis. Electron microscopy also failed to illustrate any distinct features of Behçet's syndrome, but immunofluorescent studies indicated consistent deposition of IgG.

Adult↗
PubMed1980

Action of trypsin on human plantar stratum corneum. An ultrastructural study.

Incubation of human plantar stratum corneum (SC) with trypsin at various pH suppressed the typical "keratin pattern" in the cytoplasm of the horny cells and disclosed tonofilaments and desmosomal attachment plates as they are seen in living keratinocyts. Tonofilaments were 62-75 A wide and showed a 100-120 A periodicity. This effect was non-specific since it was also obtained by incubation of SC with citric acid or sodium citrate, but it was not due to hydration alone. Partial acantholysis was obtained by incubation with trypsin followed by citric acid. After simultaneous action of trypsin in sodium citrate and in citric acid, cell membranes were separated from the cytoplasm and many of them were broken around desmosomes with subsequent isolation of desmosomes. The role of trypsin in this effect was uncertain. These findings strongly suggest that the filamentous network built up by living keratinocytes remains almost unchanged during the keratinization process although no longer visible under E.M.

Buffers↗
PubMed1980

Sebum levels during the first year of life.

Skin surface lipid levels in forty-five newborn babies and 193 infants aged less than 12 months were determined by an optical density method, using samples collected on ground glass. Although there was a wide individual range, sebum levels in the first week of life were very high, and were of the same magnitude as in adults. Females displayed a different pattern of sebum excretion from males. On the first day of life, the levels in females were lower than in the males but a large increase took place between the 3rd and 6th day, followed by a fall, bringing the level below that of the males. At 6 months the levels were low in both sexes. These findings suggest that there is a strong stimulation of sebum secretion before birth which probably stops at or soon after birth. Androgen may be involved in this stimulation and the probable role of dehydroepiandrosterone (DHEA) is discussed.

Adolescent↗
PubMed1980

Defective polymorphonuclear leucocyte chemotaxis in rheumatoid arthritis associated with a serum inhibitor.

Cellular and/or serum components of polymorphonuclear leucocyte chemotaxis were assessed in 21 patients with rheumatoid arthritis. No difference in the chemotactic migration of control and patient cells in response to a number of chemotactic solutions could be detected (P = 0.38). Deficient generation of chemotactic activity in patient sera (P = 0.58) as compared to control sera (P = 0.014) after incubation of the sera with Escherichia coli lipopolysaccharide, resulted in a significant difference in the chemotactic activity of the control and rheumatoid serum preparations for polymorphonuclear leucocytes (P = 0.0012). This defect was associated with the presence of a serum inhibitor of chemotaxis, the potency of which was inversely correlated with the level of chemotactic activity generated in the rheumatoid sera (r = -0.941, P less than 0.001).

Arthritis, Rheumatoid↗
PubMed1979

Lymphocyte studies in rheumatoid arthritis. III. A comparative study of the responses of peripheral blood and synovial fluid lymphocytes to phytomitogens.

The response of peripheral blood and synovial fluid lymphocytes to three non-specific mitogens has been studied. The paired samples were taken from patients with a range of inflammatory arthritides. Unstimulated synovial fluid lymphocytes (SFL) tended to have a greater uptake of tritiated thymidine than had unstimulated peripheral blood lymphocytes (PBL). This background uptake of tritiated thymidine by SFL showed a positive correlation with the response these SFL then showed to the mitogens. A significant depression was observed in the SFL response to phytohaemagglutinin when compared with the paired PBL response; this was seen in both the rheumatoid arthritis and other inflammatory joint diseases groups. SFL responses to concanavalin A and pokeweed mitogen, although depressed in individual cases, failed to show a significant depression overall. Attempts to restore the SFL response to that of the paired PBL by removal of any possible blocking substance from the cell surface either by pre-incubation of SFL in tissue culture medium or by enzyme treatment were unsuccessful. This suggested that cell surface blockers were possibly not the reason for deficient SFL reponses and that other factors were involved.

Arthritis, Rheumatoid↗
PubMed1979

[Haemorrhagic oedema acute in neonatal skin. Immunological and ultrastructural examination (author's transl)].

There are three reports on acute haemorrhagic oedema of the skin of infants, an illness which English-speaking authors do not individualize but only regard as a clinical variety of Henoch-Schönlein purpura. Yet the features of the disease, as described in children under two years of age, are very characteristic. --Clinical feature is the sudden appearance of oedemas on face and limbs and of cocarde-like purpura with an occasional temperature. --Histological feature is the presence of leukocytoclastic vasculitis. --Immunologically the disease is characterized by the deposit of immune complexes. --Ultrastructural examination confirms the presence of leukocytoclastic vasculitis accompanied by deposit of immune complexes and of platelets. These three reports enable the authors to study the nosological aspects of the illness among the varieties of allergic vasculitis.

Acute Disease↗
PubMed1978

Comparative electron microscopic study of clear cells in epidermodysplasia verruciformis and flat warts.

Are Epidermodysplasia verruciformis (E.V.) and disseminated flat warts different diseases? Are there any diagnostic criteria between them? In order to attempt answering these 2 questions, fundamental for prognosis and nosology, a comparative ultrastructural study was made of epidermal clear cells of 2 cases of E.V. and 4 flat warts from 4 patients of whom 3 were under immunosuppression drugs. The reason of cytoplasmic electron translucency was mainly a reduction in tonofilaments and keratohyalin amounts in E.V. and a centrifugal edema and vacuolization in flat warts. On the other hand, the number of ribosomes was raised in E.V. and reduced in flat warts. These findings allow differentiation between the 2 diseases and suggest a possible different host-virus relationship.

Adult↗
PubMed1978

Heterogeneous keratohyalin formation in warts.

The heterogenecity of keratohyalin (KH) has been demonstrated in rats, then in human warts where similar morphological features have been found and among them, dense homogeneous ovoïd single granules (SG) and composite granules (CG) apparently made up of single granules "coated" with a matrix. This work compares the ultrastructure of the KH of the tongue of newborn rats with that of common warts with and without post-fixation by OsO4, after oxydation by H2O2 and after pepsin treatment. The osmiophily of the SG is confirmed as well as the absence of osmiophily of the matrix of the CG. In man, however, the SG are resistant to oxydation by H2O2 and the CG matrix is oxydation sensitive whereas the opposite is observed in the case of rats. These differences show that it is impossible to deduce the composition of the KH in human warts from that of the rat despite their close ultrastructural resemblance but that important modification of the keratogenesis and KH formation are induced in the cells parasited by the virus of common warts.

Animals↗
PubMed1978

[Herpes gestationis. Ultrastructural and immunologic data, about two cases (author's transl)].

Herpes gestationis, a rare vesiculobullous dermatitis of pregnancy and the postpartal period, can be more easily identified today thanks to recent immunologic and ultrastructural researches. Comparing two new case reports with the data provided by the literature, underlines the individuality of the disease, in spite of the analogies it shows with bullous pemphigoid. Clinically, the illness only appears during pregnancy or the postpartal period and generally responds well to vitamin B6. Histologically the bullae at the dermal-epidermal junction are accompanied by extra- and intra-cellular epidermal edema and vacuolation of the basal cells. Ultrastructural examination shows that the initial alteration affects the plasmatic membrane of the basal cells. The immunologic mechanism of the disease is specific as the usual indirect in vitro immunofluorescent methods cannot reveal factor B.

Diagnosis, Differential↗
PubMed1978

[Cutaneous manifestations of malabsorption diseases (author's transl)].

Malabsorption (M) is characterized by absorption defect of one or several nutriments in small bowel. Its clinical expression is rarely obvious and biological signs are: anaemia, low serum protein, albumin and lipid rates, low serum calcium, phosphorus and potassium level, and hypoprothrombinaemia. But only 4 simple and reliable tests are needed for diagnosis: i. e.: daily faecal fat amount measurement, daily faecal nitrogen excretion, the xylose test and the Schilling's test. This syndrome is related to many conditions which can be divided into 2 groups with and without intestinal abnormalities. The relationships between M and skin diseases belong to 4 types (J. Marks and S. Shuster): 1) M is responsible for the cutaneous signs, 2) M is caused by a skin disease, 3) both M and skin disease are the result of a same cause, 4) M and skin disease are associated in an indirect way. Only the two first types are dealt with in this report. Skin manifestations occur as a complication in 10 p. 100 to 20 p. 100 of cases of M. They are mostly polymorphous or non-specific, as they are related to multiple vitamin or essential amino acid deficiencies and heal with the treatment of M. The main conditions encountered are diffuse pigmentation, acquired ichthyosis, follicular keratosis, nail brittleness and hair loss. Mucous membrane lesions, purpura and eczematoid or psoriasis-like dermatitis have also been described. More uncommon are clubbing of fingers, finger print abnormalities, kwashiorkor or acrodermatitis enteropathica-like eruptions. The dermatogenic enteropathy, i. e. a M syndrome due to a skin disease, occurs as a result of widespread involvement of the body for instance in psoriasis or eczema; its clinical expression is rarely obvious, the histological record of gut biopsy usually normal and the results of biological tests often dissociated, but steatorrhoea is frequently found. The pathogenesis of the condition is still unknown but its importance is related to the extent of the skin disease and it only improves with the treatment of the latter. All these features and others are discussed in the report with a comprehensive review of the literature.

Alopecia↗
PubMed1978

[Chédiak-Higashi disease (report on a new case) (author's transl)].

A typical case of Chédiak-Higashi disease is reported in a French four years old boy (no parents consanguinity). The clinical aspect of oculo-cutaneous and pilar hypopigmentation, associated with recurrent infections led to the diagnosis of C. H. disease which was confirmed by the presence of giant leukocytes granulations in the blood and giant melanosomes in epidermal melanocytes; these giant pigmented granules, are made of a limiting unique membrane with granular matrix and periodic filamentous structures, which correspond to stade I, II and III melanosomes. In keratinocytes, melanosomes are rare, never isolated and scattered in cytoplasm, but grouped in giant melanosomes complexes. No specific immunity deficiency is found in this patient but the chemotaxis of neutrophil polymorphonuclear leukocytes was decreased but restored by levamisole treatment. Concanavaline A Cap formation by polymorphonuclear leukocytes was abnormally increased, but returned at a normal level after cyclic GMP incubation and levamisole treatment. Unfortuntely, the patient died soon after accelerated phase had begun, in an anatomo-clinical picture of pseudo-lymphoma. A pathogenic discussion of CH disease is presented with the help of a study of 102 cases of literature.

Chediak-Higashi Syndrome↗
PubMed1978

Comparative electron microscopic study of clear cells in epidermodysplasia verruciformis and flat warts.

Are Epidermodysplasia verruciformis (E.V.) and disseminated flat warts different diseases? Are there any diagnostic criteria between them? In order to attempt answering these 2 questions, fundamental for prognosis and nosology, a comparative ultrastructural study was made of epidermal clear cells of 2 cases of E.V. and 4 flat warts from 4 patients of whom 3 were under immunosuppression drugs. The reason of cytoplasmic electron translucency was mainly a reduction in tonofilaments and keratohyalin amounts in E.V. and a centrifugal edema and vacuolization in flat warts. On the other hand, the number of ribosomes was raised in E.V. and reduced in flat warts. These findings allow differentiation between the 2 diseases and suggest a possible different host-virus relationship.

Adult↗