The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs ...

In this investigation, we have measured the invasion and growth of the malaria parasite Plasmodium falciparum into elliptocytic red blood cells (RBCs) obtained from subjects with homozygous hereditary elliptocytosis. These elliptocytic RBCs have been previously characterized to possess molecular defects in protein 4.1 and glycophorin C. Our results show that the invasion of Plasmodium falciparu...

Neonatal RBCs can undergo receptor-mediated endocytosis; normal adult RBCs cannot. Previously, we showed that drug-induced endocytosis, which can occur in adult RBCs exposed to amphipathic cations like primaquine, is greatly enhanced in all density-defined fractions of neonatal RBCs. To investigate the similarities and differences between receptor-mediated endocytosis and drug-induced endocytos...

In sickle cell disease (SCD), hemoglobin molecules polymerize intracellularly and lead to a cascade of events resulting in decreased deformability and increased adhesion of red blood cells (RBCs). Decreased deformability and increased adhesion of sickle RBCs lead to blood vessel occlusion (vaso-occlusion) in SCD patients. Here, we present a microfluidic approach integrated with a cell dimension...

In the last issue, I introduced this series of articles on critical software testing processes. For our first article, let’s look at the processes associated with an essential precondition for any test activities: creation, delivery, and installation of a software release into the test environment. Without software to test, there can be no software testing, but, as obvious as this is, many soft...

Phospholipid asymmetry is well maintained in erythrocyte (RBC) membranes with phosphatidylserine (PS) exclusively present in the inner leaflet. The appearance of PS on the surface of the cell can have major physiologic consequences, including increased cell-cell interactions. Because increased adherence of PS-exposing RBCs to endothelial cells (ECs) may be pathologically important in hemoglobin...

Since it is not known why sickle RBCs tend to undergo microvesiculation, we have investigated their susceptibility to thermal stress. While normal RBCs start to vesiculate at 49.0 +/- 0 degrees C (n = 14), sickle RBCs begin to vesiculate at 47.9 +/- 0.5 degrees C, with a range of 46.5 to 48.5 degrees C (n = 14). This abnormality is reproduced by treating normal RBCs with phenazine methosulfate ...

Red blood cells (RBCs) are known to perform one prominent function: to carry and deliver oxygen to the tissues. Earlier studies, however, suggested a role for RBCs in potentiating T-cell proliferation in vitro. Here it is shown that the presence of RBCs in cultures of stimulated human peripheral blood lymphocytes strengthens T-cell proliferation and survival. Analysis of phosphatidylserine exte...

In Arabidopsis thaliana, four genes have been identified in the RBCS gene family, one being assigned to subfamily RBCS-A and the other three to subfamily RBCS-B (1B, 2B and 3B). To determine the chromosomal location of these genes, hybridization analysis with CIC YAC high-density filters was carried out for the RBCS-A gene, and CAPS analysis for the three RBCS-B genes, based on the finding that...

Healthy red blood cells (RBCs) have remarkable deformability, squeezing through narrow capillaries as small as 3 microns in diameter without any damage. However, in many hematological disorders the spectrin network and lipid bilayer of diseased RBCs may be significantly altered, leading to impaired functionality including loss of deformability. We employ a two-component whole-cell multiscale mo...