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Biomedical subjects

R Brun

Publications and source records attributed to R Brun.

At least 109 records · Page 6Linked to original sources
PubMed1982

Cultivation of procyclic trypomastigotes of Trypanosoma congolense in a semi-defined medium with direct adaptation from bloodstream forms.

Bloodstream forms of Trypanosoma congolense added to the semi-defined medium 109-c (Minimum Essential Medium with Earle's salts, 60 mM HEPES, haemin, and heat-inactivated FBS) and incubated at 28 degrees C transformed into procyclic trypomastigotes. Established cultures of the procyclic forms yielded up to 4.5 X 10(7) parasites/ml. The cultivated populations consisted only of trypomastigotes and were not infective for mice. The amino acids consumed to the greatest extent were glutamine, proline, and threonine. Changes in glucose, pyruvate, and lactate concentrations during growth were determined. The procyclic organisms possessed a well-developed mitochondrion.

Adenosine↗
PubMed1982

Comparative morphometric analysis of bloodstream and lymph forms of Trypanosoma (T.) brucei brucei grown in vitro and in vivo.

The fine structure of bloodstream forms of Trypanosoma brucei cultivated in vitro, and of trypanosomes from lymph and blood of mammalian hosts, was compared morphometrically. The cell volume, quantitative parameters of the mitochondrion and of glycosomes were mainly investigated. A Coulter Channelyzer was used for the first time to measure the mean cell volume of living parasites. In vitro, the monomorphic trypanosomes between the feeder layer cells showed lower values for mitochondrial parameters than the slightly pleomorphic forms from the supernatant medium. Trypanosomes in culture were very similar morphologically to forms from lymph nodes of rats. Despite some morphometric differences between cultivated blood stream forms and those grown in vivo, the similarity of both populations was clear. Both populations, however, differed significantly from stages found in the vector or from procyclic culture forms.

Animals↗
PubMed1982

In vitro cultivation of animal-infective forms of a West African Trypanosoma vivax stock.

Animal-infective forms of a West African Trypanosoma vivax stock were grown in culture for three months using Minimum Essential Medium (MEM) with Earle's salts, supplemented with 20% inactivated goat serum over fibroblast-like cell lines isolated from the embryo of Microtus montanus or of an East African Galla crossbred goat at 36.5 degrees C and in 4% CO2 - 96% air. The bloodstream trypanosomes used to initiate the culture had been isolated from an infected goat. The cultured organisms grown in this system could be subcultured, were infective for mammalian hosts, retained their morphological characteristics and virulence, and could be readily established in Glossina morsitans centralis from goats injected with the cultured T. vivax.

Animals↗
PubMed1982

[Evolution of contact dermatitis factors in a population. Epidemiology 1975-1981 ].

Comparative results between positive patch tests found during the periods 1968-1974 and 1975-1981 are presented. The number of sensitised patients to nickel, chromate and Peru balsam has significantly increased. On the other hand, the number of turpentine-oil-positive patch tests has strongly decreased. This mirrors the drop in the imported quantities of this product. A schema concerning factors influencing the apparent allergenicity is given.

Allergens↗
PubMed1981

In vitro cultivation of bloodstream forms of Trypanosoma brucei, T. rhodesiense, and T. gambiense.

A series of new in vitro systems for the cultivation of bloodstream forms of Trypanosoma (Trypanozoon) brucei brucei, T. (T.) b. rhodesiense, and T. (T.) b. gambiense was developed. The standard system consists of a feeder layer of fibroblast-like cells derived from embryos of New Zealand White rabbits (REF( or a mountain vole, Microtus montanus (MEF), with HEPES-buffered Minimum Essential Medium (MEM), with Earle's salts, supplemented with 15% inactivated rabbit serum. These two and other feeder layers were cross-checked with different sera to test for growth support of bloodstream forms of the three trypanosome subspecies studied. Cultures could be initiated with bloodstream forms from mammalian hosts or from cryopreserved stabilates. Metacyclic forms from infected Glossina m. morsitans could also be sued as inoculum; they transformed within 6 h to bloodstream forms. Maintenance of cultures and growth properties are described in detail. Experiments were undertaken to confirm that the cultivated bloodstream forms still possess some fo the characteristic features of pleomorphic bloodstream populations. Cultivated bloodstream forms were always infective for mice, and a surface coat could be demonstrated by electron microscopy. They could also be cyclically transmitted through tsetse flies, and the metacyclic forms from these flies could be brought back into culture. In vitro cloning with single bloodstream forms and metacyclic forms could be achieve with high cloning efficiency. The consumption of glucose and the production of pyruvate and lactate were determined.

Animals↗
PubMed1980

Pyrazolopyrimidine metabolism in African trypanosomes: metabolic similarities to Trypanosoma cruzi and Leishmania spp.

Growth inhibition and radioisotope incorporation studies with allopurinol (4-hydroxypyrazolo(3,4-d)pyrimidine) have shown that the African trypanosomes are biologically and biochemically similar to Leishmania spp. and Trypanosoma cruzi with respect to their response to this compound. These organisms, as a group, share the unique ability to convert allopurinol sequentially to its ribonucleoside monophosphate and 4-aminopyrazolo(3,4-d)pyrimidine ribonucleoside mono-, di- and triphosphates.

Allopurinol↗
PubMed1980

Characterization of Trypanosoma brucei isolated from lymph nodes of rats.

Forms of Trypanosoma brucei isolated from lymph nodes of cyclically or intravenously infected rats, at different stages of infection, were morphologically compared with the corresponding bloodstream forms. Unlike the pleomorphic bloodstream trypanosome population, the lymph node trypanosome population was essentially monomorphic and resembled the slender forms of the bloodstream. Values for the morphometric parameters indicated a position between the slender and the stumpy forms. The number of trypanosomes/ml of blood showed the well-known periodic fluctuations while the number of trypanosomes/g of lymph node remained fairly constant. Serology revealed that lymph node trypanosome populations differed antigenically from the trypanosome populations isolated simultaneously frrom the bloodstream.

Animals↗
PubMed1980

Hydroxyurea: effect on growth, structure, and [3H]thymidine uptake of Trypanosoma brucei procyclic culture forms.

Hydroxyurea (HU) in concentrations above 50 micrograms/ml reversibly inhibited cell division of Trypanosoma brucei brucei stock STIB 336 procyclic culture forms, but not growth of individual cells. The volume of the nucleus and of the cytoplasm increased in the presence of the drug as did the percentage of cells with 2 kinetoplasts. Electron microscopy revealed that the nuclear membrane was extended forming protrusions which surrounded areas of the cytoplasm. Replication of the kinetoplast DNA did not seem to be affected by HU. The uptake of [3H]thymidine increased in the presence of 25 micrograms/ml HU 3-fold compared to control cells. The nuclear volume and the dry weight of the culture forms increased proportionally to the amount of label incorporated.

Animals↗
PubMed1980

Lack of delayed reaction in presence of cell-mediated immunity in trichophytin hypersensitivity.

Five patients with atopy who had chronic dermatophytosis manifested an immediate and strong trichophytin skin reaction but no delayed reaction. This phenomenon may be caused by the neutralization of injected antigen by serum antibodies during the immediate reaction. When we injected a second dose of trichophytin into the wheal of the immediate reaction, 20 minutes after the first injection, a strong delayed reaction was elicited, demonstrating cell-mediated immune responses in these patients.

Adolescent↗