Human eosinophils were cultured in the presence of recombinant human IL-3 for up to 14 d and their biochemical, functional, and density properties were assessed. After 3 d of culture in 10 pM IL-3, eosinophils had a viability of 70% compared with only 10% in enriched medium alone. Neither IL-1i,

Normodense human peripheral blood eosinophils were isolated under sterile conditions from the 22/23 and 23/24% interfaces and the cell pellet of metrizamide gradients. After culture for 7 d in RPMI media in the presence of 50 pM biosynthetic (recombinant) human granulocyte/macrophage colony-stimulating factor (rH GM-CSF), 43 +/- 7% (mean +/- SEM, n = 8) of the cells were viable; in the absence of rH GM-CSF, no eosinophils survived. The rH GM-CSF-mediated viability was concentration dependent; increased survival began at a concentration of 1 pM, a 50% maximal response was attained at approximately 3 pM, and a maximal effect was reached at concentrations of greater than or equal to 10 pM rH GM-CSF. In the presence of rH GM-CSF and mouse 3T3 fibroblasts, 67 +/- 6% (mean +/- SEM, n = 8) of the eosinophils survived for 7 d. In a comparative analysis, there was no difference in eosinophil viability after 7 and 14 d (n = 3) in the presence of 50 pM GM-CSF and fibroblasts. Culture with fibroblasts alone did not support eosinophil survival. The addition of fibroblast-conditioned media to rH GM-CSF did not further improve eosinophil viability, indicating a primary role for GM-CSF in supporting these eosinophil cell suspensions ex vivo and a supplementary role for 3T3 fibroblasts. Eosinophils cultured for 7 d localized on density gradient sedimentation at the medium/18, 18/20, and 20/21 interfaces of metrizamide gradients, indicating a change to the hypodense phenotype from their original normodense condition. In addition, the cultured eosinophils generated approximately 2.5-fold more LTC4 than freshly isolated cells when stimulated with the calcium ionophore A23187 and manifested sevenfold greater antibody-dependent killing of S. mansoni larvae than the freshly isolated, normodense cells from the same donor. Thus we demonstrate the rH GM-CSF dependent conversion in vitro of normodense human eosinophils to hypodense cells possessing the augmented biochemical and biological properties characteristic of the hypodense eosinophils associated with a variety of hypereosinophilic syndromes. In addition, these studies provide a culture model of at least 14 d suitable for the further characterization of hypodense eosinophils.

An overview of the Tropical Rainfall Measuring Mission (TRMM) Ground Validation (GV) Program is presented. This ground validation (GV) program is based at NASA Goddard Space Flight Center in Greenbelt, Maryland, and is responsible for processing several TRMM science products for validating space-based rain estimates from the TRMM satellite. These products include gauge rain rates, and radar-estimated rain intensities, type, and accumulations, from four primary validation sites (Kwajalein Atoll, Republic of the Marshall Islands; Melbourne, Florida; Houston, Texas; and Darwin, Australia). Site descriptions of rain gauge networks and operational weather radar configurations are presented together with the unique processing methodologies employed within the Ground Validation System (GVS) software packages. Rainfall intensity estimates are derived using the Window Probability Matching Method (WPMM) and then integrated over specified time scales. Error statistics from both dependent and independent validation techniques show good agreement between gauge-measured and radar-estimated rainfall. A comparison of the NASA GV products and those developed independently by the University of Washington for a subset of data from the Kwajalein Atoll site also shows good agreement. A comparison of NASA GV rain intensities to satellite retrievals from the TRMM Microwave Imager (TMI), precipitation radar (PR), and Combined (COM) algorithms is presented, and it is shown that the GV and satellite estimates agree quite well over the open ocean.

The idiopathic hypereosinophilic syndrome (IHES) is characterized by sustained peripheral blood eosinophilia associated with organ involvement in the absence of a defined etiology (1). The isolation ofeosinophils from patients with IHES has resulted in the identification of a population of eosinophils of a lower sedimentation density (hypodense) than that of eosinophils purified from healthy individuals (normodense) (2, 3). As compared with normodense eosinophils, hypodense eosinophils exhibit increases in calcium ionophore A23187-stimulated leukotriene C4 (LTC4) generation (4) and antibody-dependent helminthic cytotoxicity (3). The percentage of circulating hypodense eosinophils directly correlates with the degree ofperipheral blood eosinophilia (5), but the factors that may regulate the eosinophil phenotype in IHES have not been determined previously.A continuous exposure ofnormodense eosinophils to recombinant human granulocyte/macrophage colony-stimulating factor (rGM-CSF) (6), human rIL-3 (7), purified murine IL-5 or human rIL-5 (8) allows them to be maintained ex vivo for at least 2 wk. During this interval, the eosinophils become hypodense and exhibit both augmented calcium ionophore-stimulated LTC4 generation and antibody-dependent cytotoxicity against Schistosoma mansoni larvae . The similarity between hypodense eosinophils, which are generated in vitro by the exposure ofnormodense eosinophils to specific cytokines, and hypodense eosinophils, which are freshly isolated from the peripheral blood ofpatients with IHES, prompted an analysis of eosinophil phenotypes and cytokine activities in the peripheral blood of patients with IHES. Volume 170 July 1989 343-348 Materials and Methods Brief Definitive ReportPatients. Three patients underwent diagnostic studies to rule out collagen-vascular diseases, helminthic infections, neoplasia, drug reactions, atopy, or asthma, and each fulfilled