Biomedical subjects

F McOdimba

Publications and source records attributed to F McOdimba.

5 recordsLinked to original sources

PubMed1995

The effect of Trypanosoma brucei brucei infection on rabbit plasma iron and zinc concentrations.

Changes in plasma iron and zinc concentration were studied in rabbits following a needle challenge with Trypanosoma brucei brucei clone ILTat 2.1. The infection resulted in a decrease of the concentration of both trace elements. Plasma iron concentrations decreased gradually and were decreased maximally to 52.3% of pre-infection levels on day 18 post-inoculation. Plasma zinc concentrations, on the other hand, decreased more rapidly and were decreased maximally to 27.4% of pre-infection levels on day 3 post-inoculation. The onset of these decreases coincided with the appearance of parasites in the peripheral blood. Furthermore, the magnitude of their decrease correlated closely with the level and duration of the parasitaemia. Other abnormal findings, namely, anaemia and periods of leucocytosis and leukopenia, were also observed. This study therefore demonstrates that depression in plasma iron and zinc concentrations is part of the acute phase response in rabbits infected with this clone of T. b. brucei.

Acute-Phase Reaction↗

PubMed1993

A colorimetric assay for trypanosome viability and metabolic function.

We have adapted a tetrazolium salt (MTT) colorimetric cytotoxicity assay to the assessment of viability and metabolic function in cultured African trypanosomes. Trypomastigotes of Trypanosoma congolense and T. brucei rhodesianse were harvested from the blood of parasitemic rats and cultured under axenic conditions that support trypanosome viability and growth. Analysis of serial dilutions of these bloodstream forms indicated that the assay could detect 10(4) parasites. To assess the effect of lymphoid cytokines on trypomastigote viability, 10(5) freshly harvested parasites were cultured with a wide range of dilutions of human recombinant IL-1, IL-3, IL-6, interferon-gamma (IFN gamma) or tumor necrosis factor-alpha (TNF alpha), or bovine recombinant IFN gamma or TNF alpha for 24, 48 or 96 h. These cytokines had no apparent growth enhancing or inhibitory effect on the trypomastigotes compared with growth in supplemented medium alone. This assay has several advantages over traditional counting methods, including increased sensitivity and rapid, repeatable quantitation. This adaptation of the MTT colorimetric assay should be useful in screening drugs and host-derived factors for growth-modulating effects on trypanosomes and other extracellular protozoan parasites.

Animals↗

PubMed1992

Experimental infection with a haemorrhage-causing Trypanosoma vivax in N'Dama and Boran cattle.

N'Dama cattle control experimental infections with clones of Trypanosoma congolense of varying degrees of virulence, but nothing is known about their capacity to control infections caused by highly virulent, East African stocks of T. vivax. Thus four N'Damas and four trypanosusceptible Borans were infected with a tsetse-transmitted stock of T. vivax IL2337. In Ayrshire cattle this stock is known to cause severe haemorrhagic disease. No differences were observed in the parasitaemia between the two groups. Both groups became anaemic. The mean packed cell volume fell to 16.8 +/- 5.0% in the N'Dama cattle and to 24.2 +/- 2.2% in the Borans on day 26 post infection. These differences were not significant. Antibody responses to invariant trypanosome antigens were analysed. No differences were observed between the groups in the pattern of recognition or the isotype elicited. Antibody bound to the surface of erythrocytes was occasionally detected. No anti-platelet activity was observed. The results show that N'Dama cattle, which are known to be resistant to disease caused by T. congolense and by T. vivax stocks from West Africa, were highly susceptible to an infection of T. vivax which causes acute haemorrhagic disease.

Animals↗

PubMed1992

Purification of sn-glycerol-3-phosphate dehydrogenase from Trypanosoma brucei brucei.

A protein has been purified from the membranes of bloodstream forms of Trypanosoma brucei brucei. The purified material contained a single polypeptide chain of molecular mass 67 kilodaltons as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; under "native" conditions it migrated through a Sephacryl S-300 column with a similar molecular mass. The purified protein catalysed electron transfer from sn-glycerol 3-phosphate to oxygen with the subsequent formation of water. Electron transfer by the purified enzyme to O2 was dependent on the presence of low concentrations of the mediator phenazine methosulfate. This protein is clearly the major membrane-bound sn-glycerol-3-phosphate dehydrogenase, but it also has some characteristics suggestive of the trypanosome alternative oxidase activities.

Animals↗

PubMed1982

A comparative evaluation of the parasitological techniques currently available for the diagnosis of African trypanosomiasis in cattle.

The parasitological techniques currently in use for the diagnosis of African trypanosomiasis were compared in a series of experiments for their capacity to detect Trypanosoma congolense, T. vivax and T. brucei in the blood of cattle. The darkground/phase contrast buffy coat method proved to be more sensitive than the haematocrit centrifugation technique, thick, thin and wet blood films in detecting T. congolense and T. vivax. On the other hand with T. brucei, mouse inoculation was the most sensitive method, followed by the haematocrit centrifugation technique. In a further series of experiments involving cattle infected with either T. congolense or T. vivax, the darkground/phase contrast buffy coat method was consistently more sensitive in detecting parasites than haematocrit centrifugation, capillary concentration using glycerol and miniature anion-exchange/centrifugation techniques. As well as showing superior sensitivity, the darkground/phase contrast buffy coat method allowed species identification, estimation of parasitaemia and simultaneous assessment of anaemia (packed red cell volume).

Animals↗