In vitro studies using the plasma clot culture system have been performed in order to compare the red cell pregenitors able to rise to erythrocytic colonies in 7 days (CFUE) in the bone marrow of polycythemia vera (PV), secondary polycythemias and normal subjects. In PV but never in normal individuals or secondary polycythemias, the bone marrow cells producing erythroid colonies without addition of erythropoietin were found. The erythropoietin dode response curves in PV is biphasic with a plateau up to a concentration of erythropoietin of 0.02-0.05 i.U./ml followed by a near normal response to erythropoietin at higher doses. Thus our results demonstrate that two populations of erythroid stem cells coexist in PV, one being abnormally sensitive to (or independant of) erythropoietin, the other normally responding to erythropoietin. After remission induced by P32 treatment, the abnormal population can disappear but the prognostic significance of this disappearance is uncertain. On the whole these results are in agreement with those of others laboratories using the plasma clot culture system. The reasons of the disagreement with the data published using the methylcellulose technic of culture are discussed.

A cytological observation, using conventional fixing and staining, is made on the hemopoietic tissue in the crab, Carcinus maenas. The hemopoietic organ is formed by nodules grouping different cell types; nodules are surrounded by a limiting layer including collagenous filaments and material looking like basal lamina. Some fibrocytes and semi-granulous hemocytes are lining this limited layer. These hemocytes, more or less flattened, are transforming in fibrocytes. Fibroblast-like cells, with well developed intercellular junctions, are the first cell type: their dedifferentiation gives rise to isolated mitoting cells. We have named these mitoting cells "hemocytoblast". They are stem cells for hyaline hemocytes. Fibroblast-like cells can be compared with "reticular cells" in Insects. Uncertainty exists as to the formation and evolution of nodules.

The author describes the different techniques of reconstructive surgery of peripheral nerves and the failures that marked these trials until the advent of microsurgical techniques. After stressing the importance of the biology and physiopathology of a traumatized nerve and its stem cells, the author detailes the regeneration stages of the nerve cell when ideal conditions of axonal alignment are established by microtechniques. Considering the different notions of biology and pathology in relation to the time delay between the traumatism and referral to the surgeon, the author insists on the absolute necessity of operating during the period of full regeneration of the nerve cell, i.e. within the first 6 months.

In a case of spent polycythemia after irradiation of the spleen alone (450 rad in 17 sessions and 28 days) the suppression of any hepatic myeloid metaplasia was observed simultaneously with the regression of myelemia and erythroblastemia and the drop in the number of circulating granulomonocytic stem cells. These observations allow to discuss the mode of action of the splenic radiotherapy and the relationship between myeloid metaplasia and the circulating hematopoietic cells (proliferating granulocytic and erythrocytic cells and stem cells).

Rat embryos (8-14 days) were fixed, included and cut. Others in all cases from the same litter, were crushed on smears, in toto or after dissection. A comparative study of the two types of samples is necessary to obtain good results. Primitive erythropoietic stem cells seem to arise by the extra-endothelial way in the yolk sac mesodermic layer. They disappear when blood islands are connected to the vascular net. Primitive red cells, Perls-positive, are always intravascular in hepatic buds, normoblasts always extravascular. When grown on a medium containing hematopoietic factors, primitive (megaloblastic) cells remain megaloblastic and mature, as do the (normoblastic) definitive red cells. On a poor culture medium (Parker 199) normoblasts do not become megaloblastic. The two series, yolk sac primitive and hepatic definitive red cells, seem to proceed from individual cellular clones.

The authors report the observation of a 76-year-old man who since 1974 had a persistent anaemia considered as a pre-leukaemic state. The patient was hospitalized in May 1977 with fever and severe asthenia. The laboratory results indicated a probable diagnosis of acute non-differentiated leukaemia of stem cells. In spite of treatment, the anaemia grew worse, the leukocytosis accompanied by blast cells became more pronounced, a massive thrombopenia occurred and the patient died in irreversible shock. Cytogenetic examination done on a medullar culture revealed the presence in all the cells of a chromosome No. 5 with the long arms deleted : 46,XY,5q--. This rare medullar anomaly was reported for the first time in 1974-1975 by the Louvain school (Van den Berghe, Sokal, et al.) in a group of refractory anaemias. It has also been described in association with other chromosomal aberrations, in anaemias or other hemopathies which all developed into acute myeloblastic leukaemia. The clinical evolution and the cytogenetic data of the patient presented here are compared with those of other cases of 5q-- published in the literature, and the significance of this 5q-- chromosome aberration in hemopathies is discussed.

Leucocytes of normal individuals and patients with polycythemia vera were isolated from the peripheral blood by Ficoll-Hipaque density gradient centrifugation and cultured in vitro suing the bovine plasma clot culture technique with a minor modification: the addition of fresh normal serum. After 14 days in the presence of sheep erythropoïetin (3U/ml) erythropoïetic bursts containing between 3 and 10 subcolonies were observed in normal and polycythemia vera cultures. Blood leucocytes of patients with polycythemia vera rise to these erythropoïetic bursts without addition of erythropoïetin to the culture. This behavior was never observed in the blood of normal individuals. These results indicate that in polycythemia vera commited erythroïd stem cells of high proliferative capacity closely resembling the murine erythroïd burst forming unit have an abnormal sensitivity to erythropoïetin as well as the immediate precursors of the proerythroblasts. The culture of these cells from the peripheral blood offers some practical advantages.

Previous experiments, in dogs with fresh bone marrow or bone marrow frozen with a modified freezing system have demonstrated a 100% recovery of frozen stem cells, stored for periods up to 5 months. Five patients, three with drug resistant acute leukemia and two with metastic carcinomas, have been treated with a high dose combination chemotherapy regimen (TACC) followed by reinfusion of marrow cryopreserved with the same modified freezing system. Following the reinfusion of marrow, autologous engraftment was demonstrated on bone marrow aspiration between days 5 and 10.

Genetic marker changes in malignancy are related to an acquired disfunction of the genetic material in stem cells. This disfunction always leads to the lack of antigen; whenever we evidenced a new specificity it was an unconverted substrate. In malignant states modifications are multiple, polyclonal and independent. This least feature explains the extent of the process giving that disfunction. The evidence of a genetic defect is supported by the simultaneous decrease of the primary gene product: the glycosyl-transferase (ABO locus). In some other malignant carcinoma, blood group specificities were observed, their meaning is not well explained. Blood group specificities associated to carcino embryogenic antigen (CEA) or to some mucins could be related to the structure of macromolecular carriers.

In vitro studies using the plasma clot culture system have been performed in order to compare the red cell pregenitors able to rise to erythrocytic colonies in 7 days (CFUE) in the bone marrow of polycythemia vera (PV), secondary polycythemias and normal subjects. In PV but never in normal individuals or secondary polycythemias, the bone marrow cells producing erythroid colonies without addition of erythropoietin were found. The erythropoietin dose response curves in PV is biphasic with a plateau up to a concentration of erythropoietin of 0.02--0.05 i.U./ml followed by a near normal response to erythropoietin at higher doses. Thus our results demonstrate that two populations of erythroid stem cells coexist in PV, one being abnormally sensitive to (or independent of) erythropoietin, the other normally responding to erythropoietin. After remission induced by P32 treatment, the abnormal population can disappear but the prognostic significance of this disappearance is uncertain. In the whole these results are in agreement with those of others laboratories using the plasma clot culture system. The reasons of the disagreement with the data published using the methylcellulose technic of culture are discussed.

Research in the kinetics of cell proliferation directly interests oncologists for fundamental and pragmatic reasons. Since cancer is a perturbation of the control of cell proliferation and differentiation, such research may help to understand, the regulation mechanisms, in particular the role of microenvironment, of long range humoral factors, and of membrane site receptors. Furthermore the kinetics of cell proliferation in a normal tissue, or a tumour, influences its response to radiation or drugs. From this evolves the practical interest in research on hemopoietic tissues and on human and experimental tumors. Finally, the growth kinetics of human tumors explain their natural history and opens prospects for the treatment of intraclinical neoplastic disease and metastasis.

The present preliminary data obtained from intact fibroblasts of adult mice (polyploid stem L 929) suggest that this cell system possesses high-affinity and saturable nuclear binding sites for triiodothyronine. As estimated by the Scatchard analysis, the equilibrium dissociation constant is approximately 2 X 10(-10) moles, the maximal binding capacity is about 2 000 sites for T3 per cell nucleus.

The authors investigated the relations between cell anomalies (vacuolation, increasing sideroblastosis) caused by the uptake of alcohol and the dynamics of haematopoesis in the bone-marrow of 33 alcoholists who had been admitted in a comatose condition and who were neither affected with anaemia nor with chronic hepatitis. In all cases a maturation arrest of erythropoetic and granulopoetic cell elements which was not in accordance with the number of immature vacuolated cells could be observed. 12 test persons showed increased sideroblastic indices and a slightly diminished medullary reticulocytosis. The majority showed a very active thrombocytopoesis contrasting with the normal or even diminished number of thrombocytes in the peripheral blood. The authors come to the conclusion that alcohol will cause a general metabolic damage of haematopoesis and at the same time it will produce a direct toxic effect on the bone-marrow cells (proerythroblasts, promyelocytes) and the peripheral blood (thrombocytes).

The physiopathogeny of aplastic anemia is still unknown, it can be related to a stem cell defect or a microenvironment disease. An autoimmune origin is suspected but not as yet proved. To demonstrate the autoimmune origin of some cases of aplastic anemia, we have studied the effect of antilymphocyte globulin (ALG) on the hematopoiesis of aplastic patients by serial hematological and bone marrow investigation including blood counts, bone marrow cellularity, scanning with indium and technetium and granulocytic colonies in agar, 8 out of 17 patients had a response to ALG as shown by a rise of granulocytes and reticulocytes counts, increase of bone marrow cellularity and number of granulocytic colonies. This study tends to show that ALG has a stimulating effect on hematopoiesis in some cases of severe aplastic anemia.

Sequential measures of granulomonocytic stem cell (CFUc) pool were undertaken during chemotherapy in a case of multiple myeloma. Whereas the number of blood granulocytes remained unchanged, the total number of CFUc was markedly decreased. Therefore the CFUc marrow pool can be considered as one of the data in the management of chemotherapy. In multiple myeloma, the tumour mass can be evaluated by the secretion of monoclonal lg. It appears possible to adapt the schedule of chemotherapy considering both its effect against the tumoral cells and its toxicity on bone marrow stem cells.

Thirty two patients with malignant lymphoma - mainly Hodgkin's disease - were randomized for simultaneous treatment by high doses of metenolone during MOPP chemotherapy, to reduce its hematological toxicity. The results have shown surprisingly an increased hemato-toxicity in patients receiving androgens, with significantly more marked anemia and thrombocytopenia, reducing the total doses of anti-cancer drugs. This side effect could be explained by a cycling of the hematopoietic stem-cells and call to some caution when androgens are used during cancer chemotherapy.

The intestinal chalones 1 and 2, extracted from the intestine of the adult newt, are known to inhibit the G1 and G2 phases of the cell cycle in the embryonic intestine. The effects of these intestinal chalones on the proliferation and differentiation of intestinal cells of newt embryos were studied with special attention to the dose-response relationship, the embryonic stage and the duration of treatment. The chalone 2 triggered a linear, dose-dependent inhibition between two concentration thresholds; nevertheless about 25% of the cycling cells were not inhibited either by the highest doses injected or by repeated injections. Sensitivity to chalone 2 appeared in the intestinal epithelium at the end of embryonic development (stage 34) but the cells were not delayed in the G2 phase for more than about 20 h in spite of repeated injections. It was inferred from the doseresponse curve of the mitotic inhibition by chalone 1, that the intestinal cell population was heterogeneous: about 50% of the cycling cells were inhibited by low concentrations of chalone 1; an additional proportion of about 25% of cycling cells was inhibited by 100 x more concentrated chalone 1 and the remaining 25% was insensitive to the inhibitor. Repeated injections of chalone 1 blocked about 50% of the cycling cells definitively in the G1 phase, speeded up digestion of yolk platelets, promoted the differentiation of goblet cells and depressed the number of stem cells in the proliferative compartment located beneath the epithelium. A kinetics model of cell proliferation and cell differentiation in the intestinal cell lineages was elaborated and it was suggested that the arrest of mitotic activity and the completion of differentiation in an embryonic cell depends on two incoming signals: one is intracellular and appears when the required number of cell cycles has occured in the cell lineage, leading to a committed stem cell sufficiently differentiated to synthesise chalone and to respond to chalone; the other signal is extracellular and appears when the chalone concentration is high enough: i.e. when the required number of cells is obtained in this tissue.