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Biomedical subjects

S L Fleck

Publications and source records attributed to S L Fleck.

22 records · Page 2Linked to original sources
PubMed1985

Detection of Giardia in human jejunum by the immunoperoxidase method. Specific and non-specific results.

Rabbit antiserum to cultured trophozoites of Giardia intestinalis (G. lamblia) was used to detect organisms in jejunal biopsies using the PAP immunoperoxidase technique. In 30 sections examined from seven cases of giardiasis associated with histological changes in malabsorption, trophozoites were seen in the lamina propria in one instance, although they were otherwise seen in the intestinal lumen and surface mucus. One anti-Giardia serum reacted with the neutrophil polymorphs in all infected jejunal biopsies, and in jejunal and rectal biopsies from patients not suffering from giardiasis. The reaction with Giardia and with polymorphs could be absorbed out using washed Giardia trophozoites but not with preparations of bacteria.

Giardia↗
PubMedDate not supplied

The effect of atovaquone (566C80) on the maturation and viability of Plasmodium falciparum gametocytes in vitro.

Atovaquone (566C80), a hydroxynaphthoquinone, was investigated for activity against Plasmodium falciparum gametocytes (NF54 strain) in vitro. After 96 h of continuous exposure to the drug at 1.4 x 10(-7) M (a concentration achievable in humans 14 d after administration of a therapeutic dose of 10 mg/kg) reductions of 75%, 54% and 20% in the number of gametocyte stages 2, 3 and 4, respectively, were achieved. A small increase (14%) in stage 5 gametocytes was seen. At the same concentration, atovaquone showed greater activity against the asexual stages of P. falciparum, reductions of 93%, 96% and 43% in the number of rings, schizonts and trophozoites, respectively, being achieved. These data are consistent with inhibition of maturation of trophozoites. The observed effect on maturation of gametocytes is similarly consistent with blockade of gametocyte recruitment from merozoites produced by the preceding schizogony, or to stasis of intraerythrocytic sexual development before the formation of stage 2 gametocytes.

Animals↗
PubMedDate not supplied

Immunological detection of cytoskeletal proteins in the exoerythrocytic stages of malaria by fluorescence and confocal laser scanning microscopy.

Using monospecific antibodies, the presence and distribution of tubulin, actin, myosin, intermediate filaments, and lamins were examined in the exoerythrocytic liver schizont of Plasmodium berghei by conventional indirect fluorescent antibody methods and confocal laser scanning microscopy. The binding reactivity of the antibodies to parasite proteins was determined by Western blot analysis. The localisation of all antibodies in control host hepatocytes followed expected distributions in both uninfected and infected hepatocytes; by contrast, reactivity to the exoerythrocytic schizont was variable. The parasite reacted positively with selected anti-tubulin, -actin, and -myosin antibodies in both fluorescence and Western blot analysis. Anti-lamin antibodies were positive by confocal indirect fluorescent antibody labelling, but no labelling was detected with anti-intermediate filament antibody. Within the technical limits of resolution of the methods as applied to asynchronous parasite infections, not one of the antibodies reacting positively with the parasite by the indirect fluorescent antibody technique could be shown to identify unequivocally the classic architectural features associated with their respective target organelles, i.e. microtubules, stress-fibres or the nuclear envelope.

Animals↗