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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Levels of platelets and other hematological values were monitored in 21 Saimiri and 12 Aotus monkeys over a period of three weeks post-infection with monkey-adapted Indochina CDC-1 strain of Plasmodium falciparum. In both Saimiri sciureus boliviensis and Aotus nancymai karyotype-1 monkeys the severest thrombocytopenia was observed at 14 days post-infection coinciding with peak parasitemia, neutropenia, lymphocytosis, and anemia associated with severe hemoglobinemia and elevated fibrinogen degeneration products(FDP's). MCH and MCV profiles in Aotus monkeys decreased with ascending parasitemia. In contrast, these parameters in Saimiri were characterized by a significant compensatory increase correlating with parasitemia. In general, thrombocytopenia was one of the earliest clinical manifestations of the infection with the platelets returning to normal levels shortly after peak parasitemia at 14 days. Platelet kinetics had a strong correlation with hematologic and parasitologic values in the Aotus model. No consistent associations were observed between platelet kinetics and other parameters in the Saimiri model. These data indicate that the Aotus model for malaria is more predictable than the Saimiri. Further, platelet turnover rates and recovery provide a useful prognostic parameter during malaria infection. The results are discussed in relation to the value of the two species of monkeys as models for the pathogenesis of human malaria.
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PMID:Platelet kinetics and other hematological profiles in experimental Plasmodium falciparum infection: a comparative study between Saimiri and Aotus monkeys. 142 30

Heme, a ubiquitous iron-containing compound, is present in large amounts in many cells and is inherently dangerous, particularly when it escapes from intracellular sites. The release of heme from damaged cells and tissues is supposed to be higher in diseases such as malaria and hemolytic anemia or in trauma and hemorrhage. We investigated here the role of free ferriprotoporphyrin IX (hemin) as a proinflammatory molecule, with particular attention to its ability to activate neutrophil responses. Injecting hemin into the rat pleural cavity resulted in a dose-dependent migration of neutrophils, indicating that hemin is able to promote the recruitment of these cells in vivo. In vitro, hemin induced human neutrophil chemotaxis and cytoskeleton reorganization, as revealed by the increase of neutrophil actin polymerization. Exposure of human neutrophils to 3 microM hemin activated the expression of the chemokine interleukin-8, as demonstrated by quantitative reverse-transcription polymerase chain reaction, indicating a putative molecular mechanism by which hemin induces chemotaxis in vivo. Brief incubation of human neutrophils with micromolar concentrations of hemin (1-20 microM) triggered the oxidative burst, and the production of reactive oxygen species was directly proportional to the concentration of hemin added to the cells. Finally, we observed that human neutrophil protein kinase C was activated by hemin in vitro, with a K(1/2) of 5 microM. Taken together, these results suggest a role for hemin as a proinflammatory agent able to induce polymorphonuclear neutrophil activation in situations of clinical relevance, such as hemolysis or hemoglobinemia.
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PMID:Neutrophil activation by heme: implications for inflammatory processes. 1201 Aug 21

1. Intravenous injections of alkaline hematin in the rabbit produce an anemia the severity of which is proportional to the amount of hematin injected and the susceptibility of the animal. 2. Hemoglobinemia is an occasional consequence of hematin poisoning. 3. The leucocytes in hematin intoxication are usually increased in number and are always characterized by a high percentage of large mononuclear cells and by pigmented phagocytes. 4. The platelets are markedly reduced by alkaline hematin and ultimately a prolongation of the coagulation time of the blood and of the bleeding time results. 5. The anemia, the hemoglobinemia, the high percentage of large mononuclear leucocytes, the destruction of platelets, and the tendency to hemorrhage in malaria are all influenced by the malarial pigment, hematin.
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PMID:MALARIAL PIGMENT (HEMATIN) AS AN ACTIVE FACTOR IN THE PRODUCTION OF THE BLOOD PICTURE OF MALARIA. 1986 88