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Erythrocyte production was measured in 21 iron deficiency anemia patients after therapy with parenteral iron. The red cell mass was measured twice with 51Cr and red blood cell survival by labeling with 51Cr. In all cases, erythrocyte production increased in the 12 h following parenteral iron administration (dextran or polysaccharide-iron oxide). Production increased sharply for 3 to 6 days, remained high for 2 or 3 days and fell sharply thereafter. It is suggested that this fall is not due to a lack of available iron.

The influence of ACD and CPDA-1 anticoagulants, and storage time for 3 and 6 months on F VIII:C activity were compared in cryoprecipitate obtained at -70 degrees C, and -30 degrees C plasma freezing temperature. To eliminate variations in F VIII:C activity between donor plasma, the cryoprecipitation at -70 degrees C and -30 degrees C was made in paired plasma volumes (approximately 100 ml) from each blood unit. Employing ACD plasmas (n = 50), there was no significant difference in F VIII:C activity between cryoprecipitate prepared at -70 degrees C (mean = 31.1 IU/bag) and -30 degrees C (X = 30.5 IU/bag), and the storage did not modify F VIII:C activity. In contrast, in cryoprecipitate prepared from CPDA-1 plasmas (n = 31), the F VIII:C levels obtained at -30 degrees C (mean = 43.8 IU/bg) were significantly higher than those at -70 degrees C (mean = 37.3 IU/bag), but a deterioration of F VIII:C activity (about 50%) was observed after 6 months of cryoprecipitate storage. Therefore, if cryoprecipitate is stored it would be more convenient to use ACD instead of CPDA-1 and make cryoprecipitation either at -70 degrees C or -30 degrees C.

The non-heme iron, folates, and vitamin B12 in the liver of 77 fetuses were assayed as were serum levels of these metabolites in 70 of their mothers. The findings indicate the existence of independent placental transport mechanisms, switched on and off at different stages of late gestation, and peculiar to each metabolite.

Hemoglobin (Hb), packed cell volume (PCV), red blood cells (RBCs), mean cell volume (MCV), and mean cell hemoglobin concentration (MCHC) were measured by a single operator in a single laboratory by means of an electronic particle counter in 942 healthy adults (491 females and 451 males) residing at five altitudes: 0, 1000, 1860, 2220, and 2670 meters above sea level. The subjects were carefully screened clinically, and subjects with low transferrin saturation (less than 15%) were excluded. In both sexes there was a differential behavior as a function of altitude, of Hb and PCV on the one hand, and number of RBCs on the other. The findings suggest the presence of two sequential mechanisms of adaptation to progressively lower atmosphere oxygen pressure: One operating from sea level to 1860 meters, which leads to a progressively increasing number of relatively microcytic RBC; and a second one -- from 1860 to 2670 meters -- in which there is an increased but constant number of progressively more normocytic RBC, so that a simplistic model of equal magnitude increases in the three parameters and is seen at 2670 meters, but not at the intermediate altitudes. The middle group's comparativity, essential to these interpretations, apparently was achieved with regard to time elapsed between sampling and testing and with regard to the people integrating the groups.