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Biomedical subjects

D Poulain

Publications and source records attributed to D Poulain.

98 records · Page 6Linked to original sources
PubMedDate not supplied

Monoclonal antibody-gold silver staining dot assay for the detection of antigenaemia in candidosis.

A monoclonal antibody (Mab), designated 5B2, reacting with cell wall mannoproteins of Candida albicans has been purified and coupled to colloidal gold. The ability of the gold conjugated Mab to detect C. albicans antigens in serum during infection has been assessed in a dot immunobinding assay involving an immunogold silver enhancement procedure (GSS). A double blind study was made with sera from 140 guinea pigs, including 40 control animals and 100 infected intravenously with C. albicans. Sera from infected animals were collected either 2 days (4 animals), 15 days (9 animals), or 21 days (87 animals) after inoculation. The overall sensitivity, specificity and positive predictive value of the test were 89, 95, and 98%, respectively. However, differences were encountered in the ratio of positive tests in relation to duration of the infection. Mab-GSS dot immunobinding has also been applied, together with Mab co-counterimmunoelectrophoresis on successive sera from 2 patients who recovered from clinically and mycologically proven episodes of systemic candidosis. It was demonstrated that both patients synthesized antibodies against glycoproteins sharing the 5B2 epitope, which was initially present transiently in their sera.

Animals↗
PubMedDate not supplied

[Ultrastructural study of host-parasite relationships in epidermis during "Trichophyton mentagrophytes" infection (author's transl)].

This study presents information concerning (1) location of fungal cells within the tissue, (2) subsequent tissue alterations and (3) behaviour of immunocompetent cells. 1) During initiation of infection, the fungal cells were found to be intracellular in the lower parts of stratum corneum. Digestion of intracellular keratin is obvious, but the resistant cell wall of the squames remain unaltered. During reinfection fungal cells were located intercellulary in the upper parts of stratum corneum. 2) The study of ultrastructural changes in the underlying viable parts of epidermis reveals many alterations of keratinocytes such as mitochondrial damage, lost of tonofilaments, vacuolization, and rupture of cytoplasmic bonds. The epidermal cells are disjoined by an oedematous reaction, and these manifestations may involve large epidermic areas. 3) Cells, arising from the dermis, move into the intercellular spaces that originate from epidermal cellular dissociation. These cells are interpretated as corresponding mainly to lymphocytes, monocytes and macrophages. This cellular infiltration is intense. Most of the lymphocytes and macrophages are activated (even giant cells are to be observed). In addition, some of these cells may reach the stratum corneum, the area of parasitic location. The relationships between these manifestations and those related to cutaneous delayed hypersensitivity reactions are discussed. It seems possible to demonstrate the immunopathologic status of the reaction where some specific immunological manifestations appear to be related to the fungal growth acting in a special way by antigenic stimulation.

Animals↗
PubMedDate not supplied

[Candida albicans meningo-encephalo-myelo-radiculitis at an addict].

Beside immunodepression induced by the human immunodeficiency virus, fungal infections of the central nervous system are extremely rare in heroin-addict patients. We report here a case of meningo-encephalitis with myelo-radicular lesions in a 25-year-old intravenous heroin addict but non-HIV patient, who was admitted for an acute confusion associated with gait disorders. The diagnosis of Candida albicans meningo-encephalo-myelo-radiculitis was established by magnetic resonance imagery and mycological and serological examinations of cerebrospinal fluid. The infection was cured with amphotericin B lipid complex and 5-fluorocytosine. Early diagnosis and antifungal therapy for 6 months resulted in a favorable outcome. The detection of circulating Candida mannan in cerebrospinal fluid with a more sensitive technique combined to MRI were particularly decisive to confirm Candida infection diagnosis, allowing an appropriate antifungal therapy.

Adult↗
PubMedDate not supplied

Ultrastructure of the cell wall of Candida albicans blastospores: study of its constitutive layers by the use of a cytochemical technique revealing polysaccharides.

Cytochemical detection of polysaccharides, using the Thiéry method (PATAg) for the ultrastructural localization of periodic acid-engendered carbohydrate macromolecules, suggests eight constitutive layers in the cell wall of the blastospore of C. albicans. Each layer has been assigned a probable chemical composition according to its reactivity at the ultrastructural level. These results are discussed with respect to previous work in the field and to our present knowledge of fungal physiology.

Candida albicans↗
PubMedDate not supplied

[Ultrastructural organization of "Candida albicans" blastospore cell wall: localization of chemical and antigenic components (author's transl)].

Various ultrastructural methods were applied to study the localization of chemical and/or antigenic components of Candida albicans blastospore cell wall. They concerned: PATAg reaction for the detection of polysaccharides on ultrathin sections associated with enzymatic digestions or polysaccharide extraction; the indirect immunoferritin method on intact cells; the indirect immunoperoxidase method on ultrathin section of water soluble embedding medium; the indirect immunofluorescence test, using patients and experimental sera. The cytochemical results confirmed a previously described eight layer organization. The immunocytochemical methods, also in agreement with this stratification, showed in addition to external structures that the layer located near the plasmalemma must be considered as an important antigenic area. The mannans responsible for antigenic differences between strains of C. albicans and namely those supporting the serotype A activity were shown to be, at least, distributed among two of the described peripheral layers.

Antigens, Fungal↗
PubMedDate not supplied

[Ultrastructural and cytochemical aspects of regenerating "Candida albicans" sphero-protoplasts (author's transl)].

Subcellular modifications associated with sphero-protoplast regeneration of Candida albicans were followed with the electron microscope. After 30 min of regeneration the ultrastructural study revealed a considerable proliferation of plasmalemma invaginations and an abundant synthesis of glycogen in association with an extension of the Golgi apparatus/endoplasmic reticulum system. Later, the inflection of these invaginations and their fusion with the plasmalemma lead to a rejection of cytoplasmic areas in the cell wall. Glycogen-like particles so released in the wall were distributed in clearly delineated layers. The incorporation of cytoplasmic material through the intermediary of the plasmalemma constituted a mechanism believed to mediate the reconstitution and thus the integrity of the newly-forming cell wall.

Candida albicans↗