Biomedical subjects

M Prenant

Publications and source records attributed to M Prenant.

7 recordsLinked to original sources

PubMed1978

Three-dimensional model of bone marrow.

Three-dimensional scale models of bone marrow from a hypertransfused and a normal rat were constructed. The model of marrow from the hypertransfused rat demonstrated the existence of distinct erythroblastic islands in situ in which the erythroblasts underwent sychronous maturation. Macrophages were found in close association with the developing erythroblasts. The immature erythroblasts were tightly grouped, but as they matured they began to move apart. Erythroblasts in individual clusters were found to be at the same stage of morphologic maturation. In contrast, the model of marrow from the normal rat showed a majority of clusters containing erythroblasts at various stages of maturation. Erythropoiesis was not spatially restricted to the area proximal to the sinuses but was found to occur over the entire marrow space. Thrombopoiesis, however, was found to take place exclusively in the immediate vicinity of the marrow sinuses.

Animals↗

PubMed1978

Erythropoiesis: comparison of in vivo and in vitro amplification.

1. Amplification is defined as the phase of erythropoiesis that includes all cell divisions of the recognizable erythron. 2. In vivo, amplification always takes place surrounding a central histiocyte (erythroblastic island). It is made up of four to five successive synchronous divisions. 3. In vitro, complete maturation and amplification of erythropoietic cells can be obtained without apparent association with a central histiocyte. 4. The functional significance of the 'erythroblastic island' and disorders of amplification are discussed in relation to clinical disorders of erythropoiesis.

Animals↗

PubMed1978

On the proper use of the Soret band for hemoglobin detection in erythrocytic cells.

Intracellular hemoglobin detection by light microscopy in the Soret band (414nm) is a sensitive means of correlating morphology and biochemical function in studies of erythrpoiesis. Correct application of the technique requires a light source with strong emission in the near ultra-violet, a filter with a pass-band at 414nm, a preparation of living cells or an unfixed smear, and a receiver that is sensitive to the Soret wavelength. The human eye is very insensitive to light at 414nm and quite sensitive to stray green light: it is consequently much inferior to a black and white television or camera film for viewing a Soret image. The appearance of hemoglobin during maturation of erythroid cells in human bone marrow can be detected with greater sensitivity by this method than by a peroxidase-benzidine stain and it is the only method applicable to living cells.

Animals↗

PubMed1977

Reticulocyte motility and form: studies on maturation and classification.

A new two-stage living cell cytological classification is presented for reticulocytes in the rat and shown on an overall population basis to be the equivalent of the classical new methylene blue staining characterization. Class 1 reticulocytes (R1) are motile and multilobular. They comprise about 25% of normal bone marrow reticulocytes, but none of the reticulocytes in normal blood. Class 2 reticulocytes (R2) are asymmetrically "deep dished" in appearance and contain visible refractile granules, viewed in phase-contrast microscopy. In animals "stimulated" by bleeding, the percentage of motile marrow reticulocytes is found to be a linear function of hematocrit over the range of about 25%-70% total reticulocytes. In the blood, the associated maximum rise of class R1 is only to about 8%. These and related cellular properties are discussed with respect to the maturation and release of normal reticulocytes. Applicability of this work to studies on humans and to pathology is also indicated.

Animals↗

PubMedDate not supplied

[Isolation of erythroblastic islands. Study by optical and scanning electron microscopy (author's transl)].

1. A simple technique is described for isolation and estimation of number of erythroblastic islands (EBI) in rat bone marrow. The number of EBI decreases during hypertransfusion polycythemia, and increases during experimentally-induced hemolytic anemia. It has also been possible to maintain EBI in vitro, under culture conditions, for up to 36 hours. 2. Each EBI contains a central cell having the character of a macrophage-histiocyte which adheres to glass and spreads, while still retaining its connections with the erythroblasts. 3. In an EBI the erythroblasts are arranged in the form of concentric rings, with the outer cells being more mature than the inner. The outermost layer is frequently made up of reticulocytes even in the isolated island. The erythroblasts of a single ring appear to be at the same stage of maturation which suggests that they are derived from the same stem cell. 4. Using a coordinate reference system, studies of nuclear expulsion were made, by both optical microscopy and scanning electron microscopy.

Animals↗

PubMedDate not supplied

Origin of stress macroreticulocytes from macronormoblasts.

Stress erythropoiesis was induced in rats and guinea-pigs by graded amounts of bleeding and phenyl-hydrazine administration. Hemoglobin and DNA content was measured by microspectrophometry of single erythroblasts in the process of nuclear extrusion. DNA content was always 2 C. Hemoglobin content was in all cases superior to the normal value, occasionally reaching a value of almost twice normal.

Animals↗

PubMedDate not supplied

[In vitro studies on amplification of rat erythropoiesis (author's transl)].

From rat bone marrow in which erythropoiesis has been depressed (by suppression of erythropoietin production), liquid culture has yielded a predominantly synchronous amplification of erythroblast development. Groups of 2, 4, 8, 16 and 32 erythrolbasts are observed at 9-15 hour intervals in successive stages of maturation, similar (by their staining characteristics and nuclear size) to that seen in vivo.

Animals↗