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Biomedical subjects

L Didierjean

Publications and source records attributed to L Didierjean.

At least 55 records · Page 3Linked to original sources
PubMed1990

Biological true and false serological tests for syphilis: their relationship with anticardiolipin antibodies.

Anticardiolipin antibodies (ACA) were determined by an ELISA assay in 142 VDRL-positive patients who were classified in two groups: group I consisted of 77 patients with syphilis and group II of 65 patients with biological false-positive reaction in the standard test for syphilis. In group I 10% had ACA versus 52% in group II (p less than 0.0001). Isotype distribution in group II showed a predominance of IgG. These results suggest that antiphospholipid antibodies in VDRL and ACA tests have different specificities.

Adult↗
PubMed1989

Bullous pemphigoid and multiple sclerosis: more than a coincidence? Report of three cases.

In three patients with long-standing multiple sclerosis, bullous pemphigoid developed. The diagnosis of bullous pemphigoid was based on histologic findings, direct and indirect immunofluorescence, and Western blots showing IgG reacting with the 220 to 240 kD bullous pemphigoid antigen in the serum of three patients. Contrary to previous observations, bullous pemphigoid associated with multiple sclerosis was not different from bullous pemphigoid alone. Three similar cases have been reported previously, so the occurrence of bullous pemphigoid in patients with multiple sclerosis may be more than a coincidence.

Aged↗
PubMed1989

Heterogeneous bullous pemphigoid antibodies: detection and characterization by immunoblotting when absent by indirect immunofluorescence.

We studied sera from 59 patients with bullous pemphigoid (BP) and 25 control subjects (normal volunteers, patients with pemphigus, psoriasis, eczema, or other dermatoses) by western blotting analysis on protein bands from normal human heat-separated epidermis. BP sera reacted with four protein bands that were not detected by control sera: two major bands at 220-240 and 165 kD and two faint bands at 190 and 95 kD. Three of these bands were significantly associated with BP: 220-240 kd (51% of the BP patients; p less than 0.001), 165 kD (49%; p less than 0.001) and 190 kD (20%; p less than 0.05). These results are consistent with a molecular heterogeneity of BP antibodies, because each individual BP serum showed a distinctive pattern of reactivity. Thirty out of the 59 BP sera contained anti-basement membrane zone antibodies demonstrable by indirect immunofluorescence (IIF). All these IIF positive BP sera reacted by immunoblotting with at least one protein band: 23 (77%) with the 220-240-kD band and 21 (70%) with the 165-kD band. Furthermore, 45% of the 29 IIF negative BP sera showed a reactivity with the 220-240-kD band and/or the 165-kD band. These results indicate that western immunoblotting might be a more sensitive method for the detection of circulating BP antibodies than IIF techniques, including IIF on salt split skin.

Antibodies↗
PubMed1989

Localization and characterization of the interleukin 1 immunoreactive pool (IL-1 alpha and beta forms) in normal human epidermis.

A panel of polyclonal antisera and monoclonal antibodies (MoAb) raised against recombinant human interleukin 1 alpha (rh IL-1 alpha) and beta (rh IL-1 beta) was used to localize IL-1 pools within epidermal compartments and to characterize the immunoreactive species. Interleukin 1 alpha and beta immunoreactive species were detected by Western blot analysis only when epidermal extracts were obtained in extraction buffers containing dithiothreitol (DTT), sodium dodecyl sulfate (SDS), or 2 mercaptoethanol. Together with the 31-kD (intracellular precursor molecule) and the 17-kD (mature, secreted form) species, most of the antisera and MoAb reacted with a protein of 52-kD that was not found in several internal organs, and from which a 31-kD form could be released upon reelectrophoresis. Interleukin 1 beta immunoreactivity was consistently found by immunohistology at the level of the stratum granulosum, where IL-1 alpha immunoreactivity, although less consistently, also localized. Several monoclonal antibodies to IL-1 beta reacted intensively and specifically with epidermal basal cells. At the electron microscopical level, IL-1 beta immunoreactivity was detected in the upper layers of the stratum granulosum; it appeared to be membrane associated and suggested an exocytosis process similar to that involving lamellar bodies. These observations 1) confirm the presence of IL-1 species in the normal unstimulated human epidermis, 2) show that both IL-1 alpha and beta are detectable herein, 3) identify 52-kD IL-1 alpha and beta immunoreactive bands that appear special to the epidermis, and 4) suggest a link between epidermal IL-1 and the differentiation process of the keratinocyte.

Antibodies, Monoclonal↗
PubMed1989

Interleukin 1 alpha and beta in psoriatic skin: enzymoimmunoassay, immunoblot studies and effect of systemic retinoids.

Interleukin 1 alpha (IL-1 alpha) and interleukin 1 beta (IL-1 beta) proteins were studied by enzymoimmunoassay (EIA) and Immunoblot analysis in the 10,000 g supernatant of normal and psoriatic (lesional and nonlesional) human skin specimens. By EIA IL-1 alpha was the principal form detected in all the specimens, which contrasts with the predominance of IL-1 beta in human blood monocytes. In psoriatic plaques relatively less IL-1 alpha and more IL-1 beta were detected. On Immunoblot analysis the mature form (17 kD) was not detected in normal skin, which showed only 52-kD immunoreactive forms. In contrast the 17-kD form was found in psoriatic skin. This indicates either a distinct processing of IL-1 molecules or a contribution of inflammatory cells infiltration to the IL-1 pool in psoriatic plaques. During systemic retinoids therapy the amount of both IL-1 species decreased in lesional and nonlesional psoriatic skin.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

Calcium-binding proteins in rat skin.

Skin Ca2+-binding protein (SCaBP) was reported to be distinct from the Ca2+-binding parvalbumin (PV), however, more recently its amino acid sequence was shown to be identical to PV. We purified a protein (Mr 12,000; pI4.5) from isolated epidermis (free of other cell layers) of adult rats and whole skin (containing no PV) of newborn rats. This protein is referred to as epidermal protein (EP-12), distinct from PV in its hydrophobicity, amino acid composition and immunological properties. Previously isolated SCaBP was shown to be a mixture of EP-12 and PV. The localization and possible functions of EP-12 and of PV in skin of adult and newborn rat are discussed.

Amino Acids↗
PubMed1987

Systemic administration of etretin increases epidermal interleukin I in the rat.

We have studied the effect of systemic administration of etretin (Ro 10-1670) on the epidermal interleukin I (ILI) pool in the rat. Hairless rats were given varying doses of etretin intraperitoneally for 21 days, or a fixed dose for 2, 8 and 16 days. Abdominal skin was taken and processed for light microscopy, autoradiography (using [3H]-thymidine) and ILI assays. ILI was assayed in supernatants of epidermal extracts by both the lymphocyte activating factor (LAF) assay and the stimulation of prostaglandin E2 (PGE2) release from dermal fibroblasts. A significant increase in both LAF and PGE2 stimulatory activities was found during etretin administration. After 21 days' treatment with varying doses there was a two- to three-fold increase as compared to the controls, with a peak at 2 and 5 mg/kg. At a fixed dose a two-fold increase was found after 2 days and a three- to four-fold increase after 16 days; normal pretreatment values were restored 16 days after cessation of etretin. This is the first demonstration in vivo that a retinoid can modulate ILI content in a tissue. As epidermal ILI has been found to be decreased in psoriasis, its modulation by retinoids might have therapeutic significance.

Acitretin↗
PubMed1986

Skin calcium binding protein: effect of ultraviolet B irradiation.

Skin calcium binding protein (SCaBP) has been found in the epidermal basal layer but not in the suprabasal layers, suggesting that its presence is correlated with the position of the cell and/or the cells' low degree of differentiation and high proliferation capacity. Rats were exposed to ultraviolet B (UVB) irradiation (280-320 nm, 0.1 J/cm2) to dissociate these two main characteristics of basal layer cells. Skin biopsy specimens were taken 24 and 48 h after UVB exposure. The [3H]thymidine labeling index, SCaBP localization (indirect immunofluorescence), and SCaBP levels monitored by radioimmunoassay were investigated. The [3H]thymidine labeling index was significantly increased after UVB treatment, and the [3H]thymidine-labeled cells were present not only in the basal layer but also in the suprabasal epidermal layers. Anti-SCaBP immunofluorescence was observed in both suprabasal and basal layers (rather than exclusively in the basal layer, as in control conditions). The radioimmunoassay indicated an overall increase in skin SCaBP content. No evidence was obtained that this increase was due to humoral factors, as no changes in SCaBP concentration on cell proliferation were observed in nonirradiated epidermal areas. Topical application of a single dose of vitamin D3, equivalent to the amount synthesized by UVB exposure, was also without effect. Thus the presence of this marker is correlated with the low degree of cell maturity and the cells' ability to proliferate rather than their basal position.

Animals↗
PubMed1986

Merkel cells do not express bullous pemphigoid antigen.

Merkel cells (MC) are epithelial cells expressing cytokeratin-type intermediate filaments. They often are localized within the basal cell layer of the epidermis. Since basal cell layer keratinocytes synthetize basal membrane components, it was of interest to investigate whether or not MC could also do so. We used both double-labeling immunofluorescence and immune electron microscopy techniques with a panel of antibodies allowing the identification of MC as well as the staining of basal membrane zone components (including bullous pemphigoid antigen, laminin, type IV collagen and epidermolysis bullosa antigen). A specific loss of BP antigen expression was observed below all MC directly in contact with BMZ. This suggests that, although being an epithelial cell and in contrast to basal keratinocytes, MC does not secrete BP antigens.

Animals↗
PubMed1985

Antibodies to orthokeratotic keratinocytes in monitoring the drug-induced inhibition of parakeratotic differentiation in adult and infant mice.

Parakeratosis (PK) is a common feature of the abnormal epidermis in several disorders of keratinization. Tar phenols, retinoids and steroids which cause the inhibition of PK and the restoration of orthokeratosis (OK) are used for treating psoriasiform conditions. In this work, we studied two experimental models of the drug-induced inhibition of PK: (1) the suppression of the normal development of PK in the infant mouse tail and (2) the OK conversion of established PK in the adult tail. Two markers of OK were studied: the histological evaluation of the granular layer and the expression of cytoplasmic antigens linked to OK differentiation. It was demonstrated that high-boiling tar phenols cause a more potent inhibition of PK than betamethasone valerate. Most importantly, immunofluorescence showed that the switch to OK differentiation was located in the cells situated in a suprabasal position. The use of these immunological markers to investigate and anti-parakeratotic mechanisms has revealed that these drugs act at stages of keratinocyte differentiation which are distinct from those previously suggested.

Acids↗
PubMed1985

Activation of the alternative pathway of complement by skin immune deposits.

Skin immune deposits at the basement membrane zone have been demonstrated by functional assays to activate complement. This important biologic function has not yet been explored for immune deposits present in other locations mainly because many cytoplasmic structures in the skin have the capacity to activate the complement cascade by the classical pathway. In this study the capacity of immune deposits to activate directly the alternative pathway was examined using a functional guinea pig C3 binding test. This test was devised so as to avoid complement activation by normal cutaneous structures, thus it did not examine the capacity of immune reactants to activate the classical pathway. The main findings were that alternative pathway activation could be demonstrated only when human C3 deposits were seen by direct immunofluorescence, but not all C3 deposits were found to activate the alternative pathway; such activation was restricted to vascular deposits; the phlogistic potential of the immune deposits correlated with serologic evidence of ongoing immune reactions, i.e., hypocomplementemia and circulating immune complexes. It is suggested that this test provides data on one aspect of the phlogistic potential of skin immune deposits not detectable by direct immunofluorescence.

Animals↗
PubMed1984

Skin calcium-binding protein: effect of vitamin D deficiency and vitamin D treatment.

The amount of skin calcium-binding protein, evaluated using a sensitive radioimmunoassay and indirect immunofluorescence, was decreased in vitamin-D deficient rats and increased after one week vitamin D3 or 1 alpha-hydroxyvitamin D3 treatment. In vitamin D replete and in vitamin D-deficient animals, skin calcium-binding protein was not sensitive to changes in dietary and/or serum calcium concentrations. These results indicate that this protein is different from other calcium-binding proteins such as parvalbumin and calmodulin which are not vitamin D-dependent, and also different from intestinal calcium-binding protein which, in D replete animals, is sensitive to changes in dietary and serum calcium concentrations. Skin calcium-binding protein may, therefore, represent a new class of vitamin D-dependent protein.

Animals↗
PubMed1984

Antibodies to Merkel cells in human sera. Incidence and significance.

Antibodies to Merkel cells (MC) are not known to occur in human sera. Using a newly described technic, we looked for the presence of antibodies directed against skin structures in sera from 2,300 patients with various dermatologic and hematologic disorders, as well as graft-versus-host disease (GVHD). Three of these sera (0.1%) were found to react with MC. One monoclonal IgM antibody was present in serum obtained from a patient with chronic cold agglutinin disease, the second from a patient with GVHD, and the third from a patient with pemphigus vulgaris. The present inadequate knowledge about normal MC function and the absence of described symptoms of MC dysfunction preclude analysis of the pathogenic significance of these MC antibodies in human sera.

Aged↗
PubMed1984

Normal rabbit Merkel cells do not express neurofilament proteins.

Three hundred and five normal Merkel cells (MC) were studied in rabbit lip specimens by a double indirect immunofluorescence technique using both neurofilament (NF) antiserum and a monoclonal antibody to rabbit MC. NF proteins were not found to be expressed in MC. This suggests that MC are not neural cells and that NF-positive neuroendocrine carcinomas of the skin do not derive from MC.

Animals↗
PubMed1984

The intermediate filament proteins of rabbit normal epidermal Merkel cells are cytokeratins.

Four hundred Merkel cells (MC) have been studied by double-label immunofluorescence using: (1) a monoclonal antibody which has been previously demonstrated to react with MC and (2) antisera and monoclonal antibodies against the 5 types of intermediate filaments. It was demonstrated that MC did not react with vimentin, desmin, glial acidic fibrillary protein, or neurofilament antisera. A strong staining of MC was observed with 2 antisera and 2 monoclonal antibodies against keratin. The cytokeratin polypeptide pattern of MC is probably similar to that of simple epithelia. These findings attest to the epithelial nature of MC.

Animals↗
PubMed1984

Alterations in rat epidermis provoked by chronic vitamin D deficiency.

Long-term effects of vitamin D deficiency on epidermis were studied using histometric techniques, [3H]thymidine incorporation into DNA (labeling index), estimation of epidermal acid phosphatase activity, and one-dimensional gel electrophoresis of keratin proteins. The decrease in epidermal thickness due to a reduced number of granular cell layers and a lower level of epidermal acid phosphatase activity were observed in vitamin D-deficient rats. The number of nuclei in the basal layer was increased. No changes in labeled index due to chronic vitamin D deficiency or to 'single injection of 1,25-dihydroxycholecalciferol to vitamin D-deficient rats were observed. A comparative study of the keratin composition revealed differences in the keratin polypeptide pattern: vitamin D-deficient epidermis specifically lacked two low-molecular-weight components and presented several quantitative differences among other keratin polypeptides. The changes in epidermal morphology and metabolism that took place with vitamin D deficiency were independent of plasma calcium levels because similar modifications were present in vitamin D-deficient but normocalcemic rats (fed a diet rich in calcium and supplemented with lactose). These findings suggest that vitamin D may be one of the important factors for maintaining normal epidermal structure and metabolism through an effect on cell differentiation and formation of granular cell layers. They offer the possibility of using epidermal modification as an additional marker of vitamin D deficiency.

Acid Phosphatase↗