Biomedical subjects

F Mielot

Publications and source records attributed to F Mielot.

28 records · Page 2Linked to original sources

PubMed1984

Hemoglobin content of individual erythroblasts in hematopoietic dysplasia: marked heterogeneity at late stages of maturation.

Defective hemoglobin synthesis and gross morphologic abnormalities of erythroblasts are striking features of hematopoietic dysplasia. In order to define the effects of defective hemoglobin synthesis on hemoglobin content of erythroblasts at each stage of maturation, we measured the hemoglobin content and concentration of individual erythroblasts at various stages of maturation in the bone marrow by scanning microspectrophotometry. In contrast to normal erythroblasts, those from hematopoietic dysplasia had decreased hemoglobin content and decreased hemoglobin concentration at late stages of maturation. This observation, together with the observed near-normal hemoglobin content and concentration of circulating red cells in this disorder, suggests that polychromatophilic erythroblasts with decreased hemoglobin content fail to complete normal maturation. The abnormalities in hemoglobin content observed in vivo in hematopoietic dysplasia could be reproduced in the in vitro cultures of erythroid progenitors of bone marrow cells from the patients.

Anemia, Hypochromic↗

PubMed1981

Characterization of circulating erythroid progenitor cells in human newborn blood.

The pattern of in vitro growth of erythroid progenitors in cord blood was assayed by the methyl cellulose culture system. The erythroid nature of colonies in culture was determined by Soret band examination for hemoglobin and by immunofluorescence for specific membrane protein spectrin, as well as by conventional techniques. In contrast to adult blood cultures, we found small but definite erythroid colony growth in the cultures of cord blood progenitors in the absence of added Ep (endogenous erythroid colonies). In addition, in the presence of Ep increased numbers of progenitors were found in cord blood compared with adult blood. Comparison of cultures from newborns, normal adults, anemic adults, and adults with PV and myelofibrosis showed that endogenous erythroid colonies are also found in cultures of patients with PV and myelofibrosis but not in cultures of normal cells and cells from anemic subjects. The physiologic relevance of these endogenous colony-forming cells in newborn blood is unknown; however, we speculate that they may be related to residual extramedullary erythropoiesis at birth.

Adult↗

PubMed1980

[Granulocyte progenitor cells (CFC) culture in the adult chronic idiopathic neutropenia. A study of 12 cases (author's transl)].

Granulocyte progenitors (CFC) from 12 patients with idiopathic neutropenia were cultured in vitro and followed, in some cases, for several months. The results were similar whatever the degree of neutropenia and in the presence or absence of medullary hypoplasia. The medullary concentration of CFC was always clearly depressed, which correlated with a very low total number of CFC. In every case, when the cloning efficiency was low, there were few CFC per 10(5) metamyelocytes plated, which suggests an increase in mitotic amplification between the progenitor and the mature granulocytes. When circulating CFC were cultured, there was little or no growth, confirming the paucity of CFC in the host. No patient had an increase in cloning efficiency in marrow or blood that might have suggested ineffective granulopoiesis. In four patients, stimulatory or inhibitory activity in serum was studied; one serum was stimulatory, another, on two occasions, inhibitory. Possible machanisms for these results and their prognostic value are discussed.

Adolescent↗

PubMed1979

Enrichment of murine granulomonocytic progenitors using a continuous linear Ficoll-Isopaque gradient.

Murine bone marrow was fractionated using a Ficoll-Isopaque continuous linear gradient characterized by an osmolarity of 290 mOsm constant throughout the gradient and a physiological pH of 7.4. The cellular peak detected prior to fractionation by means of a 405 nm light beam served as a guide for determining fraction collection. Under these conditions CFC enrichment was observed constantly for densities lower than that of the cellular peak. In 17 experiments the enrichment factor amounted to 3.6 +/- 1.4. Enrichment appeared to be due to both an increase in CFC concentration and an improvement in CFC cloning efficiency. A correlation between the concentration of CFC and that of undifferentiated blasts was observed. The CFC density distribution was dependent on the cell load. For cell loads lower than 25 x 10(6) the modal density of CFC was within the range 1.0615-1.0715. For cell loads higher than 25 x 10(6) there was a shift of the distribution curve towards higher density. Clu-CFC appeared to be denser than CFC. This increase in density may be due to a maturation process from CFC to Clu-FC as a maturation gradient with increasing density was found for the granulocytic series and for erythroblasts.

Animals↗

PubMed1976

Acute myeloblastic leukemia after immunodepressive therapy for primary nonmalignant disease.

Three patients treated with immunodepressive chemotherapy over a period of 43, 60, 38 months respectively, for primary nonmalignant disease, developed AML after cessation of chemotherapy. During the months preceding the AML outbreak, there were hematologic changes with seemed to reveal a preleukemic state. Our 3 patients, and 8 previously published cases, making a total of 11 patients, developed AML after chemical immunodepression for reasons which were neither hematologic nor neoplastic.

Arthritis, Rheumatoid↗

PubMed1972