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Biomedical subjects

M Miegeville

Publications and source records attributed to M Miegeville.

At least 19 recordsLinked to original sources

[Cyclospora cayetanensis presence in aquatic surroundings in Hanoi (Vietnam). Environmental study (well water, lakes and rivers)].

Cyclospora cayetanensis is a pathogenic agent originating from the intertropical zone. It causes diarrhoeal diseases in local populations as well as in travellers visiting these zones. In the first part of this work, an epidemiological study on drinking water supply (reservoirs and consumers' taps) was conducted in Hanoi over 12 months; samples were daily collected and have revealed the presence of Cyclospora cayetanensis oocysts during the whole year in tanks and only during monsoon season. Molecular methods were used for species identification. In the second part, we tried to investigate different water sources in Hanoi city in order to detect Cyclospora cayetanensis environmental contamination: groundwaters, surface waters collected in lakes and rivers and also waters from treatment plants. Our results show that none Cyclospora cayetanensis oocyst was found in the groundwaters and in the desinfected finished waters after treatment. In contrast, in rivers and lakes samples, the level of positivity reached about 63.6% with significant differences between the districts regarding the rates of oocysts recovery: only 24% positive specimens in Hoan Kiem district, whilst respectively 80.4%, 78.3% and 65% positive samples in Hai Ba Trung, Dong Da and Ba Dinh districts. The results of this study seem to confirm that environmental water is contaminated by Cyclospora cayetanensis oocysts and points out the importance of water as a significant source of human transmission. It is quite obvious that observation could be probably extended to the other endemic areas.

Cyclospora↗

Adherence of platelets to Candida species in vivo.

The in vivo interactions of platelets with Candida species yeast cells were investigated in a murine model. Mice were injected intravenously via the lateral caudal vein, and blood drawn by periorbital puncture was collected in phosphate-buffered saline-formaldehyde to avoid in vitro platelet activation. The study of the clearance of blastoconidia of Candida albicans and Candida glabrata showed that these cells disappeared quickly from the bloodstream. Microscopic observation of blood samples, stained by Calcofluor white or May Grunwald Giemsa, demonstrated the rapid attachment of platelets to fungal elements of all the Candida spp. tested. The attachment of murine platelets to C. albicans cells, observed by scanning electron microscopy, revealed morphological changes. The platelets lost their discoid shape, generated pseudopodia, and flattened against the yeast cells. The reversibility of platelet binding to C. albicans by chelating agents suggests a cation-dependent link. In contrast, the fixation of C. glabrata and Candida tropicalis was not modified by chelating agents. The mechanisms involved in the in vivo adherence of platelets to Candida cells may therefore differ according to the species of Candida.

Adhesiveness↗

[Optimization of parasitological diagnosis of human intestinal microsporidiosis].

The diagnosis of microsporidiosis by staining stools is known to be fast and cheap. To obtain a specific and sensitive result, two colorimetric methods must be used: staining by the fluorochrome Uvitex 2 B (VAN GOOL) and trichrome. Among the four staining methods of trichrome currently studied, the WEBER coloration could be considered as the most efficient. The density of microsporidia spores could be semi-quantitatively evaluated, because their distribution is homogeneous.

Azo Compounds↗

[Fusaria infection in patients with neutropenia: apropos of 3 cases].

The authors report three cases of fusarial infection in neutropenic patients with hematologic malignancies. The first patient was affected by a cutaneous extensive fusariosis. The second patient developed a fusarial lung infection during a multiple organ failure following allogenic bone marrow transplantation. The third patient who presented with refractory acute myelogenous leukemia, developed fusarial skin lesions, and died from pulmonary failure. The treatment of fusarial infection is disappointing and requires amphotericin B, in association with hematopoietic growth factors. The role of new agents, or combination chemotherapy remains to be determinated. The recovery of adequate neutrophil levels is the most important factor in the resolution of fusarial infection.

Adult↗

Binding of resting platelets to Candida albicans germ tubes.

The binding of resting platelets to Candida albicans germ tubes was studied by means of an affinity column in which germ tubes were physically immobilized. Adhesion of platelets to the column was dependent on both the germ tube concentration and the number of platelets applied. It was found that the interaction of C. albicans germ tubes with platelets is specific and should be mediated by a fungal protein receptor. The results obtained by scanning electron microscopy confirmed that resting platelets can fix directly onto germ tubes. In addition, this study showed that attachment of platelets onto C. albicans is associated with morphological changes. Platelets lost their discoid shape, became globular, generated spikes or pseudopods, and then flattened on the yeast cells.

Blood Platelets↗

[Anisakiasis in the Nantes area. From fishmongers' stalls to medical offices].

1,103 fish-fillets belonging to 4 species were examined during one year, during a survey conducted among commercial marine fish-fillets in the Nantes area (west coast) in France. Anisakis simplex L3 were found in 3 different species and most of them are frequently present in coal fish (Pollachius virens) and whiting (Merlangius merlangus). We report 6 cases of human anisakiasis (3 certain cases and 3 probably cases). Diagnosis was established in 3 cases by microscopic analysis of intestin bowel specimens (eosinophilic granulomas and/or parasitic fragments) and in 3 cases gastroscopy. Serodiagnosis was positive in 1 case and the consumption of undercooked fishes was found in 5 cases. This work emphasizes the role of anisakiasis as a source of digestive symptoms and intestinal eosinophilic granuloma.

Adult↗

Microsporum gypseum complex in man and animals.

Twenty-eight strains of the Microsporum gypseum complex isolated from humans and animals were studied. The perfect form was found for 25 of the isolates. Nannizzia incurvata was the species most frequently involved in human pathology, while Nannizzia gypsea was most frequently found on animal lesions. Nannizzia fulva was rarely involved pathologically and Nannizzia corniculata was not isolated during this study. It is surprising to note that this species was not found even though most of our strains (22/28) came from Africa. Reliable methods are not available for differentiating among the anamorphs, which are commonly called M. gypseum, Microsporum fulvum or Microsporum boullardii. The Sabouraud medium conventionally used for medical mycology makes almost no distinction among them. We found that the species could be easily distinguished by colonial and microscopic features when grown on Takashio medium. When strains are atypical, sexual reproduction remains the reference technique but, in most cases, Takashio medium makes it possible to avoid this long drawn-out procedure.

Adolescent↗

The role of dental canal fillings in the development of Aspergillus sinusitis. A report of 85 cases.

Radiopaque concretions in the maxillary sinus in cases of sinusitis are often observed in infections with aspergillosis. For several authors, such features are considered to be typical of these infections. For us this foreign body in most cases is believed to be related to overfilling of the teeth. We have previously drawn attention to this fact. We report 85 cases of aspergillosis of the maxillary sinus. Cases involving immunosuppressed patients were excluded because of very different clinical conditions. A radiopaque foreign body was seen in 94% of the cases. Of this group, 85% were believed to be related to overfilling of maxillary teeth with dental paste, particularly since evidence for endodontic treatment was found in the premolar/molar region. An image of intrasinus dental paste was demonstrated in 12% of the cases as a direct extension of filling paste from affected teeth. The nature of the dental paste is important because the zinc contained can stimulate the growth of Aspergillus fumigatus. In vitro studies in our laboratory also showed that the growth of A. fumigatus was stimulated with a low concentration of zinc.

Adolescent↗

[Use of scanning electron microscopy coupled with transmission electron microscopy in comparative studies of the relation between Schistosoma mansoni and Salmonella typhimurium].

Relations between Schistosoma mansoni and Salmonella typhimurium are studied in vivo and in vitro using scanning and transmission electron microscopy as complementary methods. Salmonellae adhesion is a specific process materialized in special places of male and mature schistosome tegumental surface. Interactions are marked by bacterial strong fibres creating a network all around Schistosoma where Salmonellae are dividing. Membrane junction is the last stage leading to symbiotic balance between two biologic systems.

Animals↗

[Babesiasis, pediatric malaria: does confusion exist in Africa?].

The authors describe a case of febrile disease acquired by a nursling in Africa: was it induced by Pl. falciparum or by Babesia sp.? In spite of numerous microscopic and serological appraisals from veterinary and medical authorities, it is difficult to state definitively this subject, but it is more probably a babesiosis of canine or rodent origin.

Animals↗

[Specificity in the relationship between Salmonella typhimurium and Schistosoma mansoni].

Special interaction between Salmonella typhimurium (STM) and Schistosoma mansoni is considered under two complementary aspects, in vivo and in vitro, using scanning and transmission electron microscopy. The resulting observations have obviously permitted us to discover a large specificity in these adhesion phenomena that seems to lead to the fusion of membranes between the two organisms. Microanalysis trials executed in these areas of strong affinity were attempted.

Animals↗

[Possible transfer between sarcomatous mouse cells (BP8) and yeasts (Saccharomyces cerevisiae, whole bodies and protoplasts)].

From our observation in vitro, we can suggest that : a direct contact between sarcomatous cells and physiologically active yeasts appears to be necessary for the transfer of the radioactive labelling; the presence of a filter with pores of 1.2 micrometer diameter prevents passage of fragments of DNA or RNA between the cells; this transfer is a very small fact, but implies about the third of the yeasts.

Animals↗

[Observation of Schistosoma mansoni by scanning electron microscopy].

The integumental surface of adult Schistosoma mansoni was studied by scanning electron microscopy (SEM) at 220 to 10,000 magnifications. SEM shows certain basic features such as spines in the oral sucker and the acetabulum which may facilitate rasping and attachment of the parasite to stay in the bloodstream of the definitive host. It seems likely that SEM visualization will be a means for differentiation some species of the genus Schistosoma.

Animals↗

[New scanning electron microscopy contribution to the study of yeast protoplasts].

Study by scanning electron microscopy enables us to describe with precision the morphology of protoplasts. We can confirm that the wrinkles more or less perceptible on the protoplasts studied, do belong to the morphology of those just mentioned, that the presence or the absence of globulous component is connected with the physiological activity of the cell and that it is possible to distinguish the different protoplasts thanks to their morphological aspect.

Candida↗