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A Vernes

Publications and source records attributed to A Vernes.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Application of a co-electrosyneresis reaction to the diagnosis and serological surveillance of candidiasis in a hospital milieu].

We have previously described a co-immunofiltration reaction which identifies a specific precipitating system (SPCS) in sera from patients presenting systemic candidiasis. The SPCS is characterized by coalescence with an experimental serum directed against the germinative tubes of Candida albicans. The present study concerns our experience of the use of co-immunofiltration in routine hospital practice. Complete observations involving clinical, mycological and serologic data were selected in order to illustrate various possible developmental trends for SPCS during candidiasis. The SPCS usually develops early infections due to the yeast species most frequently implicated in hospital pathologies; an increase in its intensity reflects a developing infection or the start of therapy. The SPCS disappears slowly and gradually when infectious development is favorable, but its sudden disappearance represents an unfavorable prognosis correlated with detection of circulating antigens. Circulating antigens are also seen in severe cases of candidiasis in which the SPCS is not present. Indeed there is a certain complementarity between these two observations.

Antibody Formation↗
PubMed1986

[Human anisakiasis: 5 cases in northern France].

We report 5 cases of human anisakiasis revealed respectively by an acute intestinal obstruction due to multiple small bowel stenosis, an acute inflammatory ileitis simulating appendicitis, ulcer type epigastralgia, purulent peritonitis and a latent small bowel tumor. Diagnosis was established in 4 cases on microscopic analysis of bowel specimens (eosinophilic granulomas and/or parasitic fragments) and in 1 case at gastroscopy. Serodiagnosis was positive in 2 of 4 cases and the consumption undercooked fishes was found in 4. In small samples we estimated the infestation (1 to 50 parasites) by anisakis larvae of 3 fish species: 80 p. 100 for herrings, 63 p. 100 for mackerels and 100 p. 100 for whitings. This work emphasizes the role of anisakiasis as a source of digestive symptoms and intestinal eosinophilic granuloma.

Adult↗
PubMed1985

[Use of a method of lipid extraction from Candida albicans cell walls blastospores. Ultrastructural implications concerning their localization and parietal microfibril organization].

A chemical method for lipid extraction has been applied to Candida albicans blastospores previously to their examination by transmission electron microscopy. The results led to the concept of a superficial location of lipids bounded to the peptidopolysaccharidic matrix of the cell wall. This lipid extraction also allowed us to describe cell wall microfibrillar structures. Two types of microfibrills have been particularly identified: microfibrils of approximately 50 A in diameter, involved in a network of the cell wall intermediate layers and supposed to correspond to beta 1-3 glucans; fibrillar structures of 120 A in diameter, similar to chitin microfibrils, observed in the bud scar septum.

Candida albicans↗
PubMed1985

Influence of medium osmolality on the in vitro growth of Plasmodium falciparum: a morphologic and radioisotopic study.

The study of the growth rate and incorporation of [3H]hypoxanthine and [14C]isoleucine showed that in vitro variations of Plasmodium falciparum parasitemia levels and incorporation rates of the two radiolabeled molecules have been correlated. In our experimental conditions, P. falciparum blood forms in vitro tolerate osmolalities ranging from 180 to 360 mOSM. A weak hypo-osmolality (241 mOSM) favored the development of the parasite. The highest sensitivity of the parasite to osmotic variations was observed during schizogony. The merozoite stage and reinvasion process seemed less affected by hypo-osmolalities than by hyperosmolalities. The minor alterations in morphology of the parasites in hypo- and hyperosmotic media suggested that P. falciparum may have efficient osmoregulatory power.

Animals↗
PubMed1985

A 50 kilodalton exoantigen specific to the merozoite release-reinvasion stage of Plasmodium falciparum.

The immunoglobulins G of a human plasma inhibiting in vitro Plasmodium falciparum merozoite reinvasion have been purified and used to immunoprecipitate the antigens released into the culture medium by an [35S]methionine-labeled synchronous culture. Several of the major exoantigens identified were found throughout the entire life cycle; they were also immunoprecipitated from the labeled parasitized cells. Some antigens were found only after the reinvasion stage, and especially a major one of molecular mass 50 kDa and pI 5.5. The latter was not found in the parasitized cells but derived most likely from the processing of a major 126 kDa antigen which disappeared from the parasites during the reinvasion period and which was immunoprecipitated by an anti-50 kDa monoclonal antibody.

Antigen-Antibody Complex↗
PubMed1985

In vitro inhibition of Plasmodium falciparum merozoite invasion by human plasma fibronectin.

Human fibronectin isolated from citrated blood was tested for its ability to bind to Plasmodium falciparum by an indirect immunofluorescent assay using rabbit antiserum to human fibronectin. A positive reaction was observed on merozoites inside schizont-infected erythrocytes. The binding was not observed on non-parasitized red blood cells. The effect of human fibronectin on P. falciparum growth was further studied using an in vitro inhibition assay; 50% inhibition of parasite multiplication was obtained with approximately 100 micrograms/ml of human fibronectin. Slight inhibition was observed below 10 micrograms/ml. The significance of this finding is discussed.

Animals↗
PubMed1985

[Lipoproteins and malaria. I. Immunogenicity of serum lipoproteins in mice infected with Plasmodium chabaudi].

Anti-lipoprotein antibodies (anti-Lp Ab) have been investigated during the course of acute infection with P. chabaudi in Swiss mice using a radio-immunoprecipitation assay with (125)-iodine radiolabelled lipoproteins from normal or infected mice. Antibodies were detected 11 days after the beginning of infection; however, the highest lipoprotein precipitations were observed with purified (125)-I labelled lipoproteins from day-5 or day-7 infected mice. P. chabaudi infected mice were treated with chloroquine at various intervals after the beginning of infection and anti-Lp Ab were assayed on day 13. Anti-Lp Ab were not observed in mice treated before day 7 but were present in all mice treated after day 7. Anti-Lp Ab were not detected in mice infected with P. yoelii 17 X. Injection of purified lipoproteins from day-7 P. chabaudi infected mice (Lp day-7) to normal uninfected mice did not induce an antibody response to lipoproteins but anti-Lp Ab were observed when the same injection was performed in P. yoelii infected mice. Moreover, anti-Lp Ab were detected in uninfected mice injected concomitantly with Lp day-7 and hematin extracted from malarial pigment. Our results suggest that anti-Lp Ab observed in P. chabaudi infected mice are mainly against modified lipoproteins produced during infection and that the induction of the antibody response against lipoproteins requires an adjuvant effect such as the hematin which is released during infection.

Animals↗
PubMed1985

[Lipoproteins and malaria. II. Immunoregulatory role of immunoglobulin-lipoprotein complexes in mice infected with Plasmodium chabaudi on antibody producing cells].

Injection of lipoproteins from Plasmodium chabaudi infected mice into mice previously immunized with either human serum transferrin, bovine serum albumin, polyvinyl-pyrrolidone or tetanus toxoid, was followed by a decrease in the levels of antibodies directed against these antigens, suggesting a blockade of antibody secreting cells (Goumard et al., 1982). However, lipoproteins in P. chabaudi infected mice are complexed with immunoglobulins during the second week of infection (Demonchy et al., 1982). In this study, the effects of lipoproteins and Ig-lipoprotein complexes (Ig-Lp) on antibody secreting cells was investigated in vitro. Spleen cells from mice immunized with tetanus toxoid were cultured in microplates and the antitetanus antibodies (anti-TT Ab) were measured in the culture supernatants using a radioimmunoassay (Goumard et al., 1984). Ig-Lp purified from day-11 or day-13 P. chabaudi infected mice inhibited the secretion of anti-TT Ab when introduced into microcultures. On the contrary, lipoproteins purified from either day-5, day-7, day-21 or day-28 infected mice as well as lipoproteins from uninfected mice did not inhibit anti-TT Ab secreting cells. Ig-Lp formed in vitro with lipoproteins purified from day-7 infected mice (Lp J-7) and day-20 infected mice sera, inhibited anti-TT Ab secreting cells. IgG purified from day-20 sera and incubated with Lp J-7, inhibited anti-TT Ab secreting cells but no inhibitory effect was observed with the F(ab')2 fragments of these Ig. Pre-incubation of anti-TT Ab secreting cells with Fc fragments of mouse IgG blocked the inhibitory effect of Ig-Lp purified from infected mouse sera or formed in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Stage-specific antigens at the surface of erythrocytes infected by Plasmodium falciparum. Preliminary study].

Immunofluorescence microscopy, and ultrastructural immunolabelling have been used to localize antigens determinants present on the surface of prefixed erythrocytes infected by P. falciparum. Two classes of antigens have been demonstrated: 1) one located on intact erythrocytes close to the site of invasion; 2) another detected after saponin treatment, and distributed over the entire surface of infected erythrocytes. Such antigens appeared to have a variable expression according to the stage of the parasite.

Animals↗
PubMed1985

Antigenic variability of Candida albicans.

The concepts of modern biology lead us to think that all structures are liable to continual changes. Ultrastructural and biochemical methods have been able to objectify such a dynamic in Candida albicans, an opportunistic yeast. A broad analysis of antigens is a reliable way to study the antigenic variations which concern this organism. Numerous information on somatic and metabolic antigens of C. albicans is available at the moment. Paradoxically, if one accepts studies dealing with dimorphism, very few works have shown antigenic variability of this species or investigated the mechanisms involved in such a variability. The few approaches done in this way tend to prove that it may be possible to link together the expression of particular antigens and the behavior of the yeast, particularly when it acts as a pathogen.

Animals↗
PubMed1985

Parasitologic and immunologic studies of experimental Plasmodium falciparum infection in nonsplenectomized chimpanzees (Pan troglodytes).

Parasitologic, hematologic, and immunologic parameters were monitored in intact (nonsplenectomized), adult chimpanzees infected with a "chimp-adapted" strain of Plasmodium falciparum. Following primary and secondary injections of 10(9) P. falciparum-infected erythrocytes, each chimpanzee developed a low grade parasitemia (up to 1,000/mm3) and maintained the infection without evidence of eliminating the parasites. Hematologic and serum biochemical values, as well as the majority of immunologic parameters tested, remained unaltered in infected chimpanzees. However, 2 weeks after infection T cells from infected chimpanzees demonstrated an enhanced response in vitro to stimulation with the mitogen PHA, and monocyte phagocytic activity for antibody-coated erythrocytes (Fc-mediated phagocytosis) increased significantly. During malarial infection, apes developed a strong T cell proliferative response to P. falciparum antigens and monocytes showed enhanced phagocytic activity for P. falciparum-infected erythrocytes in the absence of immune serum. These results suggest that cellular immune mechanisms, especially macrophage activation, may help control, but not eliminate, P. falciparum malaria in chimpanzees.

Animals↗
PubMed1985

[Malarial infection of the placenta. Parasitologic, clinical and immunologic aspects].

Among 1,206 pregnant women tested in Franceville (Gabon), 36.4% showed a positive parasitemia as compared to 21.9% of 154 non pregnant (p less than 0.001). Increase in the incidence of parasitemia appeared at the 4th month of pregnancy with two peaks at the 5th (44.4%) and 9th months (43.6%). Of 741 placenta studied, 33% showed plasmodial pathological changes; placental lesions were associated with a decrease in mean placental weight (26 g; p less than 0.001) and birth weight (220 g; p less than 0.001). Parasitemia during pregnancy and placental changes were more frequent in 1st or 2nd parous women and were associated with a decrease of inhibitory antibody titres in mothers at delivery, and with a synthesis of specific antibodies by the foetus i.e. with a transplacental transmission of plasmodial antigens to the foetus. Maternal inhibitory antibodies were constantly detected in cord blood and this could account for the absence of plasmodium in the 1,128 cord blood samples which have been examined.

Female↗
PubMed1984

Cytochemical and ultrastructural studies of Candida albicans. III. Evidence for modifications of the cell wall coat during adherence to human buccal epithelial cells.

Ultrastructural modifications of the cell wall coat of Candida albicans during adherence to host cells were investigated using various cytochemical techniques. Attachment of the fungus to buccal epithelial cells appeared to involve spatial rearrangement of their cell wall surface. In particular adhering yeast developed a fibrogranular surface layer visualized by the periodic acid--thiocarbohydrazide--silver proteinate technique (a polysaccharide detection technique); Concanavalin A binding sites detected on their cell wall coat were highly increased. Attachment of yeasts to epithelial cells appeared mediated by fibrillar structures or polysaccharidic granules distributed on the cell wall coat. But free extra-cell wall material containing mannoproteins released from the yeast surface suggested additional mechanisms.

Adhesiveness↗
PubMed1984

Plasmodium falciparum strain-specific human antibody inhibits merozoite invasion of erythrocytes.

The extent to which human antibodies involved in functional immunity react with antigenic determinants varying between different isolates or strains of the human malaria parasite Plasmodium falciparum will influence the design of vaccines against malaria. We identified nine immune sera from Cambodian refugees which blocked in vitro invasion of erythrocytes by merozoites of the Camp strain of P. falciparum and agglutinated Camp strain merozoites. However, none of these sera blocked invasion of erythrocytes by merozoites of the FCR-3 strain. We conclude that antibodies in these human sera recognized antigenic determinants present on the surface of viable merozoites of the Camp strain but not the FCR-3 strain. These parasite strains and in vitro assays can be used to analyze strain-specific functional immunity in humans.

Adolescent↗