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Biomedical subjects

J H Saurat

Publications and source records attributed to J H Saurat.

At least 19 recordsLinked to original sources
PubMed1992

Expression of CRABP-I and -II in human epidermal cells. Alteration of relative protein amounts is linked to the state of differentiation.

The physiological role of cellular retinoic acid-binding proteins (CRABPs) may be to influence the intracellular level of free retinoic acid in the cell. In the present study two isoforms of CRABP, CRABP-I and CRABP-II were partially characterized in various human Malpighian epithelia and in human cultured keratinocytes expressing various patterns of differentiation. We have developed a new sensitive radiobinding assay using a PAGE/autoradioblotting technique which effectively separates CRABP-I and CRABP-II. This method allows the simultaneous quantification of these proteins. We show that CRABP-I and -II have similar M(r) values (15,000), but differ in their dissociation constant towards retinoic acid (Kd of 16.6 nM and 50 nM respectively), in pI (4.86 and 5.13) and in their relative mobilities (RF) on PAGE under nondenaturating conditions (RF values 0.65 and 0.44). In addition, we show that CRABP-II is the major isoform expressed in human keratinocytes, in vivo as in vitro. Furthermore, we demonstrate that CRABP-II is actually the CRABP previously studied in epidermal cells by a PAGE assay (Siegenthaler & Saurat (1987) Eur. J Biochem. 166, 209-214) and whose levels are dramatically increased by retinoic acid and its analogues in human epidermis. Keratinocytes, in the absence of full terminal differentiation, as well as hyperplasia, such as cultured human differentiating keratinocytes, psoriatic plaques, and non-keratinized oral mucosa, contained high levels of CRABP-II. CRABP-I was not detected in cultured keratinocytes, whereas normal skin (at full terminal differentiation) expressed CRABP-I and CRABP-II at a ratio of approx. 1:1.4. This value was approx. 1:17 in lesional psoriatic skin and 1:8 in oral mucosa. These observations suggest that CRABP-I and -II are regulated differently in human keratinocytes. The sharp increases in CRABP-II levels are associated with an alteration in the differentiation programme, as well as with cell response to retinoic acid overload, whereas CRABP-I might be a marker for terminal differentiation.

Animals↗
PubMed1992

[Schoenlein-Henoch syndrome in adults and skin infection].

Schoenlein-Henoch purpura is a rare disease in adults clinically characterized by palpable purpura, mainly on the legs, with varying degrees of gastrointestinal, articular and renal involvement. This syndrome is also characterized by IgA-vasculitis and its pathogenesis is still unclear, although it appears frequently after a viral or bacterial infection especially in the ORL sphere. We report here the cases of three adult patients who developed Schoenlein-Henoch purpura shortly after a bacterial infection of the skin, notably by Staphylococcus aureus.

Aged↗
PubMed1992

[Bacillary angiomatosis: apropos of a case].

We report a case of bacillary angiomatosis (BA), a recently described opportunistic infection, in a 30-year-old patient with Aids who was referred for a purplish vascular nodule on the forehead, of one-month duration, surrounded by similar smaller papules. For the previous 4 months he had suffered from progressive cachexia with fever, chills, night sweats, arthralgias and bone pain for which no infectious or malignant cause had been discovered after an extensive medical work-up. Histological examination of the skin lesions using Warthin-Starry staining revealed lobular vascular proliferation and protuberant endothelial cells with clumps of small bacilli. These findings were confirmed by electron microscopy. We believe that this is the first case of BA diagnosed in Switzerland and discuss the skin lesions, systemic symptoms and evolution under antibiotic treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A common precursor for CD4+ T cells producing IL-2 or IL-4.

To investigate whether CD4+ T cells are predetermined to produce a given pattern of lymphokines, we have used a culture system that allows the controlled induction of either IL-2- or IL-4-producing CD4+ T cells. Single, freshly isolated murine CD4+ T cells were activated with Con A, rIL-2, and APC; the developing clones were split and then cultured for an additional 14 days with either rIL-2 alone or with rIL-2 and anti-CD3 stimulation. Subclones expanded in the presence of rIL-2 alone produced predominantly IL-2, although subclones derived from the same precursor and expanded in the presence of rIL-2 and a mitogenic antibody to CD3 released predominantly IL-4. Subclones expanded for 2 wk in the presence of rIL-2 plus a mitogenic mAb to CD3 released up to 60 times more IL-4 but only 1/90 the amount of IL-2 released by subclones derived from the same precursor cell and expanded with rIL-2. Both phenotypes can be derived from IL-2-producing precursor cells. These results demonstrate that IL-2-producing clones can be derived from the same cells as IL-4-producing clones and are most consistent with the view that the IL-2-producing Th1 or the IL-4-producing Th2 phenotype of a T cell clone is acquired during T cell differentiation and is not secondary to the expansion of distinct subpopulations that are predetermined to produce a specific cytokine pattern.

Animals↗
PubMed1992

Central role for TCR/CD3 ligation in the differentiation of CD4+ T cells toward A Th1 or Th2 functional phenotype.

Activated CD4+ T cells can be classified into distinct subsets; the most divergent among them may be considered to be the IL-2 and IFN-gamma-producing Th1 clones and the IL-4 and IL-5-producing Th2 clones. Because Th1 and Th2 clones can usually be detected only after several months of culture, we used conditions that modulate the IL-2 and IL-4 production in short term culture. Here we show that freshly isolated and subsequently in vitro-activated CD4+ T cells that were cultured for 11 days with rIL-2 and restimulated showed a IFN-gamma+ IL-2+ IL-3+ IL-4- IL-5- pattern. Because these cells were not capable of providing B cell help for IgG1, IgG2a, or IgE in an APC- and TCR-dependent T-B cell assay, they expressed a phenotype typical for most Th1 clones. In contrast, activated T cells that were cultured for 11 days with IL-2 plus a mAb to CD3 and then restimulated produced a IFN-gamma- IL-2- IL-3+ IL-4+ IL-5+ pattern. These cells were capable of providing B cell help for IgG1, IgG2a, and IgE synthesis and thus presented a phenotype typical for Th2 clones. Similar results were observed when mitogenic mAb to Thy-1.2 or to framework determinants of the alpha beta TCR were used. The induction of Th1- and Th2-like cells did not depend on the relative expression of CD44 or CD45 by the T cells before activation in vitro. Because the incubation of activated T cells with anti-CD3/TCR mAb induced high unrestricted lymphokine production, the latter might be responsible for the Th2-like lymphokine pattern observed after restimulation. To address this point, TCR V beta 8+ and V beta 8- T cell blasts were co-cultured in the presence of mAb to V beta 8. After restimulation, V beta 8+ cells had a IL-4high IL-2low phenotype and V beta 8- cells had a IL-4low IL-2high phenotype. This demonstrates that TCR ligation but not lymphokines alone are capable of inducing Th2-like cells, and this points out a central role for the TCR in the generation of T cell subsets.

Animals↗
PubMed1992

[Retinoids in dermatology].

Retinoids are natural substances, similar to vitamin A, and acting through nuclear receptor on the gene transcription, with a similar mechanism to steroid hormones. Synthetic retinoids are used in the treatment of different skin diseases including severe acne, abnormal keratinization, psoriasis, epidermoid carcinoma, and inflammatory skin lesions. Systemic or local administration of these compounds acts on the proliferation and differentiation of the skin structure by not clearly understood pathway. This pathway could be either an agonist, antagonist or substitutive modulation of the natural retinoid action or a separate pathway. The different drugs have in common, teratogenic properties, which limit their usefulness.

Administration, Oral↗
PubMed1992

Epidermal and splenic antigen-presenting cell function in a retrovirally induced murine immunodeficiency syndrome (MAIDS).

Since alterations of epidermal Langerhans cells (LC) have been observed in humans infected with HIV, we investigated the morphology and function of these cells in murine acquired immunodeficiency syndrome (MAIDS), a murine model closely resembling human AIDS. The number as well as the shape of dendritic MHC class II+ cells from ear skin of C57BL/6 mice were similar in normal and infected animals. In mixed epidermal cell (EC) lymphocyte cultures, EC from infected mice and from normal mice stimulated allogeneic T cell proliferation to the same extent. In contrast to T cells from normal mice, however, T cells from infected mice did not respond to allogeneic spleen cells, confirming the presence of a T-cell defect in MAIDS. Subcutaneous injection of syngeneic mice with trinitrophenyl-modified MAIDS EC resulted in delayed ear swelling responses after challenge that were equivalent to those induced by hapten-modified EC from normal mice, suggesting that the contact sensitivity inducing potential of MAIDS LC was preserved. To investigate antigen presenting and processing function, EC and spleen cells were tested with the ovalbumin-specific IAb-restricted T cell hybridoma BO.17.10 and either ovalbumin 323-339 peptide or intact ovalbumin protein. MAIDS spleen cells had a reduced antigen presenting capacity compared with normal spleen cells, whereas EC from these mice showed the same processing and presenting capacity as normal controls. In summary, our results demonstrate that the frequency, morphology, level of MHC class II antigen expression and ability to process and present antigen is normal for LC from mice with MAIDS whereas the function of splenic T cells and APC from infected mice is significantly impaired.

Animals↗
PubMed1992

Gap junctional communication of primary human keratinocytes: characterization by dual voltage clamp and dye transfer.

We have compared dye coupling in pairs of small (less than 10 microns in diameter) and large (greater than 20 microns in diameter) keratinocytes isolated from normal human epidermis, using Lucifer yellow microinjection. Under control conditions, dye coupling was found in only 1 out of the 25 small pairs tested, whereas it was evident in 75% of the large pairs (n = 52). After a 30-min incubation of the latter pairs in the presence of 10(-6) and 10(-4) M all-transretinoic acid (RA), the percentage of coupling was 53% (n = 15; NS) and 7% (n = 14; P less than 0.001), respectively. The almost complete uncoupling observed after 10(-4) M RA was not reversible even 30 min after return to control medium (n = 8). Dual whole-cell patch-clamp recordings from large keratinocyte pairs showed a macroscopic junctional conductance (gj) of 9 +/- 2 nS (n = 43), which was abolished by heptanol (3.5 mM) in a fully reversible way. Compared to heptanol, 10(-4) M RA abolished keratinocyte gj more slowly and irreversibly (n = 10). By contrast, 10(-6) M RA had no significant effect on gj (n = 8). Single-gap junctional channels were also identified between large keratinocytes. Events histograms of 152 transitions from three experiments revealed three main unitary conductances (gamma j) of 45 +/- 4, 78 +/- 4, and 106 +/- 7 pS. The dye coupling results indicate that junctional communication is markedly different in pairs of small and large cells, which showed the phenotype and keratin markers of basal and suprabasal keratinocytes, respectively. In the latter cell type, coupling is ensured by channels of three sizes and is blocked irreversibly by pharmacologic concentrations of RA.

Alcohols↗
PubMed1992

Orbital and palpebral paraffinoma.

Paraffinoma is a well-recognized complication of paraffin injection. We describe a 44-year-old man who had an ethmoidectomy for chronic sinusitis. A communicating fracture of the ethmoid bone into the orbit occurred intraoperatively. The nasal cavity was subsequently packed with gauze containing a petrolatum-based antibiotic ointment. Bilateral, periocular swelling developed 1 week later. Optical and electron microscopic studies revealed a paraffinoma.

Administration, Intranasal↗
PubMed1992

Side effects of systemic retinoids and their clinical management.

The safety profile of oral retinoids appears to be well established, although rare new side effects are occasionally reported. Appropriate patient selection, use of the lowest required dose, and adequate follow-up are significant factors in the prevention of these toxicities. Teratogenicity, which can be avoided by following recommended precautions, is the main adverse effect.

Humans↗
PubMed1992

The major cicatricial pemphigoid antigen is a 180-kD protein that shows immunologic cross-reactivities with the bullous pemphigoid antigen.

Recent studies have shown that sera from patients with cicatricial pemphigoid (CP) contained autoantibodies against epidermal antigens of molecular weight 230 kD and/or 180 kD by immunoblotting, similar to those recognized by bullous pemphigoid (BP) sera. Previous immunoprecipitation studies have shown that BP sera only precipitated the 230-kD antigen. To characterize the CP antigen(s) we tested 10 CP sera, 10 BP sera, and four controls by both immunoprecipitation of radiolabeled cells and immunoblotting of epidermal extracts. For immunoprecipitation, we used 0.5% NP-40 extracts of both normal human keratinocytes and Pam cells. All CP sera precipitated a 180-kD protein that co-migrated with the BP180 antigen precipitated by some individual BP sera. Two of these CP sera also faintly bound a 230-kD protein of similar molecular weight as the major BP230 antigen. CP and BP sera with an immunoblotting pattern of 180 kD immunoprecipitated a co-migrating 180-kD protein. CP sera reacting by immunoblotting with the 230-kD antigen precipitated the 180-kD and/or the 230-kD antigen. In contrast, BP sera reacting with the 230-kD antigen only precipitated this antigen. In further experiments, labeled 0.5% NP-40 extracts from Pam cells were first preabsorbed with a reference BP serum and then immunoprecipitated with CP sera. Under these conditions, CP sera that immunoprecipitated both 180-kD and 230-kD proteins with the standard procedure no longer precipitated these proteins. Our results suggest that a 180-kD protein is the major CP target-antigen that demonstrated immunologic cross-reactivities with the BP180 and the BP230 antigens.

Antigens↗
PubMed1992

Interleukin 1 immunoreactivity in sebaceous glands.

Interleukin 1 (IL-1) immunoreactivity in sebaceous glands was studied in paraffin sections of normal human skin. A panel of antibodies against IL-1 alpha and beta was tested using an immunoperoxidase labelling method. All the antibodies showed a similar specific labelling pattern: both glandular and ductal cells were immunoreactive for both IL-1 alpha and beta, provided optimal tissue fixation was used.

Adult↗
PubMed1992

A prospective immunofluorescence study of 111 cases of pruritic dermatoses of pregnancy: IgM anti-basement membrane zone antibodies as a novel finding.

Since 1981, all pregnant women presenting to our department with a pruritic dermatosis have been investigated by histological and immunopathological techniques. We recruited 111 patients and performed skin histology in 77, 109 direct immunofluorescence tests (DIF), 74 indirect immunofluorescence tests (IIF) and 15 Western blots (WB). We identified: (i) five typical cases of pemphigoid gestationis (PG) (4.5%), corresponding to an incidence of 1/7000 pregnancies. (ii) Five cases without PG but showing circulating anti-BMZ antibodies of IgM type. With the exception of one case, clinical features were homogeneous--occurrence of erythematous papular and/or urticarial lesions on the trunk, and less often, on the limbs between the 32nd and 38th week of pregnancy. Rapid clearance of lesions within a few days was the rule. Whenever performed, DIF was negative and IIF showed circulating anti-BMZ antibodies of IgM type. Western blot studies were negative in these five cases. (iii) One hundred and one cases with negative immunofluorescence tests, considered to be suffering from polymorphic eruption of pregnancy. Our results show the value of systematic immunopathological investigations in pregnant women presenting with a pruritic dermatosis, and raise the possibility of a new entity, as defined by circulating anti-BMZ antibodies of IgM type.

Adult↗
PubMed1992

Overexpression of cellular retinoic acid-binding protein type II (CRABP-II) and down-regulation of CRABP-I in psoriatic skin.

Cellular retinoic acid-binding proteins (CRABPs) might exert a physiological function by controlling the intracellular levels of free retinoic acid. The aim of this study was to analyze the relative expression of CRABP-I and CRABP-II in lesional (LPS) and nonlesional (NLPS) psoriatic skin. CRABP-I and -II proteins were analyzed by a PAGE-autoradioblotting technique, and their respective mRNA were studied by RNA blot and in situ hybridization. We found that CRABP-II levels were 6-fold higher in LPS and 2-fold in NLPS as compared to normal skin, whereas CRABP-I levels were decreased in NLPS and LPS. CRABP-II mRNA were grossly overexpressed in all LPS and some NLPS specimens. These results indicate a switch to the overexpression of CRABP-II mRNA in psoriasis which induces high levels of the protein mainly in LPS; these observations may be relevant to the pathophysiology and therapy of psoriasis as CRABP-I and -II have different ligand-binding affinities.

Carrier Proteins↗
PubMed1992

Fox-Fordyce disease: successful treatment with topical clindamycin in alcoholic propylene glycol solution.

We report a 66-year-old woman with a 3-year history of intensely pruritic follicular papules in the axillar, pubic and inguinal areas. Previous treatment with topical fusidic acid and gentamicin sulfate was ineffective. The clinical and histological examination was consistent with Fox-Fordyce disease. Application of clindamycin in an alcoholic propylene glycol solution led to the clearing of the lesions within 1 month. Nine months later, the treatment was stopped, and no recurrence was observed.

1-Propanol↗
PubMed1992

Hip surgery skin cellulitis.

Of 583 erysipelas/cellulitis seen in our Department between 1981 and 1991, six (1.04%) were localized to the buttock and hip. Five patients had had a dynamic hip screw implanted for coxarthritis on the side where the skin infection developed. This does not appear to be secondary to superinfection of the surgical wound as the erysipelas/cellulitis occurred weeks (7 to 520) after surgery. The possible surgical compromise of the venous/lymphatic circulation appears to be the causative factor. In all patients, the course was satisfactory upon systemic antibiotic therapy and no recurrence was seen after a mean follow up of 28 months.

Adult↗
PubMed1992

Frequency of bullous pemphigoid-like antibodies as detected by western immunoblot analysis in pruritic dermatoses.

BACKGROUND AND DESIGN: Ninety-seven patients suffering from a pruritic dermatosis were screened for the detection of bullous pemphigoid (BP) antibodies (ab) using the Western immunoblot (WB) analysis technique. RESULTS: Twenty-four patients (25%) reacted at least twice with the BP antigen on WB analysis at a 1/10 dilution: seven had typical BP, four had papular BP, 10 had pruritus and prurigo of unknown origin, two had eczema, and one had lichen planus. This corresponds to 13% of BP-type ab in patients who did not fulfill criteria for BP. Therefore, we did the following: (1) tested a control group of 24 subjects; (2) assessed the reproducibility of the WB method by retesting the same serum samples on different epidermal extracts; and (3) estimated the BP ab titer. None of the 24 control subjects had detectable BP ab, and reproducible results were obtained in all groups when serum samples were retested at the 1/10 dilution. Although 86% (6/7) of patients with BP had BP ab titers of 1/100 or greater, only 60% (6/10) of the group with pruritus and prurigo and 33% (1/3) of the group with eczema reached such titers. CONCLUSION: These results indicate that due to its sensitivity, the WB method can detect low titers of BP ab in patients with pruritic dermatoses who did not fulfill criteria for BP, and therefore we question the specificity of this method.

Adult↗