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Biomedical subjects

A Vernes

Publications and source records attributed to A Vernes.

At least 55 records · Page 3Linked to original sources

[Preferential action of chloroquine on Plasmodium within mature erythrocytes].

In vitro studies on the effects of chloroquine on Plasmodium berghei in relation to the age of the host cell made it possible to demonstrate the preferential effect of the drug on parasites growing in mature red blood cells. The ED-50 for parasites in mature red blood cells is lower (1,64 +/- 0,2 mg/kg/day) than in reticulocytes (2,45 +/- 0,2 mg/kg/day). The result of clumping test for chloroquino-sensitive P. berghei growing in young red blood cells, is almost similar as in a chloroquino-resistant strain of the same species. These results are compared with physiological observations on Plasmodium host parasite relationships and bioclinical discrepancies noticed between in vivo chloroquine sensitivity of P. falciparum wild strains versus in vitro testing.

Animals↗

[Fungal infections: involved species and minimal inhibitory concentrations of common antifungal agents].

Fungal cultures of cutaneous or ungual origin (477 cultures), nasopharyngeal and urogenital origin (2,000 cultures), and blood, internal organs, surgical incisions, and catheters (300 cultures) were obtained in this study. Analysis of the data yielded the following information: Candida albicans and C. tropicalis, frequent causes of superficial or systemic mycoses, were very sensitive to flucytosine and amphotericin B in a liquid medium, but less sensitive to the imidazole derivatives; C. parapsilosis, a cause of superficial and systemic mycoses, was remarkably sensitive to all four antifungal agents tested; Torulopsis glabrata and C. krusei are of greatest concern in a hospital setting since systemic or visceral infections are minimally sensitive to antifungal agents; C. pseudotropicalis, C. guilliermondii, and C. zeylanoides are less pathogenic and sensitive to antifungal agents varies, depending on the strain. Specific measures are presented for management of fungal infections in a hospital setting. The role of antifungal susceptibility testing in everyday practice is also evaluated.

Amphotericin B↗

Antigenic variations of Candida albicans in vivo and in vitro--relationships between P antigens and serotypes.

Serum samples from patients with candidosis and from rabbits experimentally infected with serotype B C. albicans strains consistently showed higher antibody titers against Candida strains with serotype A antigens than strains with serotype B antigens, in indirect fluorescent antibody tests. When sera from rabbits infected with C. albicans serotype B strains were absorbed with blastospores of the homologous strain they continued to react against strains of C. albicans serotype A and a C. tropicalis strain with serotype A antigens. Serotype A-specific antisera reacted against tissue forms of C. albicans serotype B in vivo and against serotype B germ tubes, but not their parent blastospores, in vitro. These findings suggest that C. albicans B serotype cells may sometimes express, in vitro or in vivo, one or several antigens so far considered as specific of serotype A. The results have implications for the classical concept of C. albicans serotypes and for the serological diagnosis of candidosis in relation with the previously described strain P variable antigens.

Agglutination Tests↗

[Parasitologic study of feces: simultaneous performance of Faust's, Janecko-Urbanyi's and Ritchie's concentration technics].

The authors propose the simultaneous use of Faust's, Janeckso-Urbanyi's and Ritchie's techniques according to a protocol which combines the effectiveness of the three techniques, with a saving in reagents, a significant simplification of the manipulations (a single dilution of the stools, a single straining and a total of three centrifugations) and the possibility of conducting valid comparative studies, as the three techniques are performed from the same faecal aqueous suspension.

Feces↗

[Parasitic infestation and haemoglobinopathies in a population of 1170 refugees from South East Asia].

One thousand one hundred and seventy refugees from Cambodia, Laos and Vietnam were examined in the north of France from 1976 to 1980. 58% of them carried digestive parasites, 22% had anti-Plasmodium antibodies and 2% showed circulating Plasmodium. The most frequent parasites were hookworms (28%), Opisthorchiidae (15%) and Giardia intestinalis (12%). Strongyloides stercoralis (5,7%), Entamoeba histolytica (4,5%), tapeworms (3,3%), human coccidia (1,3%) and Trichostrongylus sp. (1%) were less frequent. Four cases of japonicum schistosomiasis were diagnosed by rectal biopsy. Three species of Plasmodium were identified: P. falciparum (10 cases), P. vivax (3 cases) and P. malariae (2 cases). 16% of the refugees displayed E haemoglobin (Hb E). The occurrence of parasitic infestation and Hb E were more frequent in Cambodians and Laotians than in Vietnameses. Specific anti-P. falciparum antibodies were observed with a significant higher frequency in patients carrying Hb E.

Adolescent↗

[An ultrastructural study of spermatogenesis in Trichinella spiralis Owen 1835 (Nématode Trichuroide) (author's transl)].

The ultrastructural study of spermatogenesis in T. spiralis demonstrated the main characteristics of the male germ cells in the class Nematoda, i.e. lack of flagella, lack of reconstitution of the nuclear envelope after the meiotic divisions, and atypical structure of the centriole. The spermatozoon of T. spiralis was compared with previous classifications of the nematoda spermatozoa.

Animals↗

Trichinella spiralis in rats: in vivo effects of the bile and in vitro action of secretory IgA from bile.

The biliary secretion of rats is diverted from the choledoch duct to the bladder. These rats are resuscitated by sub-cutaneous injections of a salt solution and then infected with Trichinella spiralis larvae. It is shown that the number of adult worms is increased (+ 66%); as is the female larvae production (+ 51%); the females' length is also increased (+ 25%). 40 days after the infection the number of muscular larvae is considerably increased (+ 79%) in comparison with control rats. Secretory IgA (SIgA) from rats bile were tested in vitro on the female production of larvae. This larvae production was more inhibited (59%) by immune SIgA than by control SIgA (25%).

Animals↗

Experimental study of resistance to infection by Trichophyton mentagrophytes: demonstration of memory skin cells.

The mechanisms governing the development of local immunity in experimental dermatophytosis were studied by injecting intravenously trichophytin in guinea pigs cured of a prior Trichophyton mentagrophytes infestation. Dermal cell modifications were observed which were greater in the healed zones than in those not affected during the prior dermatophyte inoculation. These modifications included lymphocyte activation and accumulation and an accumulation of basophilic leukocytes. These observations suggest that after an acute dermatophyte infection heals, immunocompetent cells remain which are more numerous at the sites of lesions and that these cells would be responsible for the increased rate of elimination of the fungus during a reinfection. This hypothesis is discussed in the framework of the relationships observed in dermatophyte infections between delayed type hypersensitivity and resistance.

Animals↗

[Changes of serum lipoproteins during the course of human malaria (author's transl)].

Triacylglycerides (TAG), total cholesterol (TC) and serum lipoproteins (SLP) were studied during the course of 12 cases of human malaria and one case of simian inui malaria. The erythrocytic schizogony induced quickly an increase of TAG, a decrease of TC and modifications of SLP such an increase of VLDL parallel with a decrease or a disappearance of HDL. These modifications, always clear-cut, were not correlated with the intensity of parasitaemia or the species of Plasmodium. They were transient but longer than those described in connection with experimental rodent malaria. The changes of HDL could be associated with defective triglyceride removal of the plasma compartment due to an inhibition of the lipoprotein lipase induced by the parasite.

Animals↗