Maturation of Plasmodium falciparum in multiply infected erythrocytes and the potential role in malaria pathogenesis.

Erythrocytes containing two or more parasites, referred to here as multiply infected erythrocytes (MIEs), are common in the blood of humans infected by Plasmodium falciparum. It is necessary to study these cells closely because the excess numbers of parasites they contain suggest that they could be overloaded with virulence factors. Here, microscopic examinations of blood smears from patients showed that up to seven merozoites can successfully invade an erythrocyte and mature to ring stage.

Possible relationship between Plasmodium falciparum ring-infected erythrocyte surface antigen (RESA) and host cell resistance to destruction by chemicals.

Repeated incubation of Plasmodium falciparum culture in 0.015% saponin solution for a total of 35 min destroys most of the uninfected cells, leaving only the ring-infected erythrocytes (RIEs). Parasites concentrated by this method can subsequently complete the asexual cycle and infect other erythrocytes.

Hemozoin accumulation in Garnham bodies of Plasmodium falciparum gametocytes.

Garnham bodies are curious objects exclusive in erythrocytes containing sexual forms (gametocytes) of Plasmodium falciparum. Although the name is familiar, only a few photographs of Garnham bodies (G-bodies) have been published. Considering that other objects in malaria-infected erythrocytes, such as Schuffner's dots of Plasmodium vivax and Maurer's clefts of P.

Erythrocyte membranes convert monomeric ferriprotoporphyrin IX to β-hematin in acidic environment at malarial fever temperature.

Hemozoin production makes it possible for intraerythrocytic malaria parasites to digest massive quantities of hemoglobin but still avoid potential ferriprotoporphyrin IX (FP) toxicity, which they cannot decompose further. Some antimalarial drugs, such as chloroquine, work by inhibiting this production, forcing the parasite to starve to death. As part of the efforts to identify possible biological mechanisms of FP polymerization, we have used normal human erythrocyte membranes as a model, to promote β-hematin (β-h) synthesis.

Microscopic detection of mixed malarial infections: improvement by saponin hemolysis.

Objective: The objective of the present study was to determine whether saponin hemolysis could improve microscopic detection of malaria parasites in human blood, since it has been previously reported that the technique has been used to enrich Plasmodium falciparum culture to >or=90% parasitemia.

Material And Methods: Blood samples from suspected malaria cases were first examined in routine thick and thin smears under the microscope. The sample (1 ml) was then hemolyzed with 0.