White blood cell counts and malaria.

White blood cells (WBCs) were counted in 4697 individuals who presented to outpatient malaria clinics in Maesod, Tak Province, Thailand, and Iquitos, Peru, between 28 May and 28 August 1998 and between 17 May and 9 July 1999. At each site and in each year, WBC counts in the Plasmodium falciparum-infected patients were lower than those in the Plasmodium vivax-infected patients, which, in turn, were lower than those in the uninfected patients. In Thailand, one-sixth of the P. falciparum-infected patients had WBC counts of <4000 cells/microL. Leukopenia may confound population studies that estimate parasite densities on the basis of an assumed WBC count of 8000 cells/microL. For instance, in the present study, use of this conventional approach would have overestimated average asexual parasite densities in the P. falciparum-infected patients in Thailand by nearly one-third.

Cell population dynamics model for deconvolution of murine embryonic stem cell self-renewal and differentiation responses to cytokines and extracellular matrix.

Stem cell self-renewal versus differentiation fate decisions are difficult to characterize and analyze due to multiple competing rate processes occurring simultaneously among heterogeneous cell subpopulations. To address this challenge, we describe a mathematical model for cell population dynamics that allows flow cytometry measurement of population distributions of molecular markers to be deconvoluted in terms of subpopulation-specific rate parameters distinguishing commitment to differentiation, proliferation of differentiated cells, and proliferation of undifferentiated cells (i.e., self-renewal). We validate this model-based parameter determination by means of dedicated, independent cell-tracking studies. Our approach facilitates interpretation of relationships underlying effects of external cues on cell responses in differentiating cultures via intracellular signals.