Production of erythrocytes that contain fetal hemoglobin in anemia. Transient in vivo changes.

Serial microscopic immunodiffusion assays of F cells, i.e., erythrocytes that contain fetal hemoglobin (HbF), in four individuals recovering from anemia demonstrate initial increases in the percentage of circulating reticulocytes that contain HbF (F reticulocytes) and subsequent increases in the percentage of mature erythrocytes that contain HbF (F erythrocytes).

Individual variation in the production and survival of F cells in sickle-cell disease.

The protective role and underlying sources of the elevated levels of fetal hemoglobin associated with sickle-cell anemia were reassessed by microscopical immunodiffusion assays. Three variables that contribute to levels of fetal hemoglobin were examined: the percentage of fetal-hemoglobin-containing reticulocytes produced; the quantity of fetal hemoglobin synthesized within such cells; and the extent to which the fraction of fetal-hemoglobin-bearing erythrocytes is enriched beyond the level produced. Four general findings emerged from analysis of 29 patients: each variable is separately regulated; the expression of each is often distinctly different between individual patients; contrary to prior speculation, production of fetal hemoglobin may be as great in the absence of heterocellular hereditary persistence of the hemoglobin as in its presence; and fetal hemoglobin does not, as often supposed, guarantee preferential cell survival.

Microscopic method for assaying F cell production: illustrative changes during infancy and in aplastic anemia.

Fetal hemoglobin (HbF)-bearing reticulocytes (F reticulocytes) can be detected in peripheral blood by a modification of the microscopic single-cell radial immunodiffusion method. Thereby otherwise inappreciable changes in HbF production can readily be recognized. F reticulocyte frequencies are reporducibly measurable whenever the product of whole blood HbF-bearing red cell (F cell) frequency and reticulocyte frequency is approximately 5 X 10(-4) or greater.

The distribution of satellite and main-band DNA components in the melanogaster species subgroup of Drosophila. I. Fractionation of DNA in actinomycin D and distamycin A density gradients.

Fractionation of total adult DNA of five of the seven species of the melanogaster species sub-group of Drosophila in actinomycin D and distamycin A caesium density gradients has revealed the presence of three main-band DNA components, common to all species, and ten satellite DNAs that are distributed between the species. Satellite DNAs are either unique to a species or common to two or more species. The abundance of a common satellite DNA varies between species.

Inferences from genetical evidence on the course of meiotic chromosome pairing in plants.

Meiotic chromosome pairing is a process that is amenable to genetic and experimental analysis. The combined use of these two approaches allows for the process to be dissected into several finite periods of time in which the developmental stages of pairing can be precisely located. Evidence is now available, in particular in plants, that shows that the pairing of homologous chromosomes, as observed at metaphase I, is affected by events occurring as early as the last premeiotic mitosis; and that the maintenance of this early determined state is subsequently maintained by constituents (presumably proteins) that are sensitive to either colchicine, temperature or gene control.

Hemoglobin SC, SS/GPhiladelphia and SOArab diseases diagnostic importance of an integrative analysis of clinical, hematologic and electrophoretic findings.

Hemoglobin studies are presented on two children in whom electrophoretic analysis of hemolysates at alkaline pH initially suggested the diagnosis of hemoglobin SC disease. In both patients the course of the disease was unusually severe, blood smears contained irreversibly sickled cells, and crystal formation did not occur when red cells were incubated in 3 per cent sodium chloride solution. Each of these findings is inconsistent with the interpretation of the electrophoretic patterns.

Changing erythrocyte populations in juvenile chronic myelocytic leukemia: evidence for disordered regulation.

Fetal and adult erythrocyte characteristics were studied serially in a 30-mo-old female with juvenile chronic myelocytic leukemia. On presentation the erythrocytes exhibited predominantly fetal characteristics as indicated by 69% hemoglobin F (HbF), 1.1% hemoglobin A2 (HbA2), absent I antigen, and fetal levels of the erythrocyte enzymes, carbonic anhydrase I and II, glucose-6-phosphate dehydrogenase, hexokinase, pyruvate kinase, and lactate dehydrogenase; 100% of the erythrocytes present contained HbF.

Delineation of peripheral bone infarcts in a child with a rare hemoglobinopathy (SOArab) and purpura fulminans: case report.

A 27-month-old patient with SOArab hemoglobinopathy complicated by purpura fulminants was studied with 99mTc-pyrophosphate. The study showed an absence of radiotracer in the bones of both feet and the distal portions of both hands, along with an increased concentration of radiotracer proximal to the regions of absent radiotracer. Subsequent amputation of the distal portions of all four extremities was necessary because of dry gangrene.