Tumoral stem cells capable of multiplying can be selected from human tumours by in vitro culture techniques. These are the cells which renew the tumour and form metastases. Placed in a suitable agar medium, they give birth to cellular clones. The selection of clone-forming cells from human tumours makes it possible to devise chemograms, as has successfully been done in the U.S.A. by the Salmon and von Hoff teams. Working on a fairly large number of different cancers and using in vitro tests in the presence of drugs, these scientists were able to predict chemosensitivity and chemoresistance in 62 to 96% of tumours. The new techniques and results are presented and discussed.

The preleukemic states are disorders which constitute early phases of acute non-lymphoblastic leukemia. The nomenclature associated with the preleukemias has been confusing, and therefore the problems of their definition and diagnosis are discussed. The laboratory investigations are reviewed and the contribution of cytogenetic and cell cultures to improved knowledge of the pathophysiology is stressed. The preleukemic states are clonal hematopoietic stem cell malignancies manifested by maturation and proliferation defects of the different cellular strains of the marrow. Treatment of preleukemias remains controversial. While the use of cytostatic drugs is not generally accepted, remissions are reported to have been achieved by polychemotherapy. Chemotherapy in patients with severe complications of cytopenias thus appears to be justified. On the other hand, controlled studies of therapy in preleukemic states are needed.

Autologous bone marrow transplantation represents a new approach to the treatment of malignant diseases when conventional therapy has failed. For this reason, the authors have collected bone marrow from 46 patients, including 24 with acute leukaemia, 7 with chronic myeloid leukaemia, 10 with lymphosarcoma and 5 with solid tumours. The mean of total cryopreserved CFU-c was 8.5 X 10(6) (range: 0.2-25). Ten cases of autologous bone marrow transplantation are reported. Seven patients had been prepared with high dosage chemotherapy alone (TACC) and three with chemotherapy combined with total body irradiation. Haematopoiesis restarted within 9 to 15 days in 5 patients and within 22 to 34 days in the other 5. Complete remission was obtained in all 5 patients with acute myeloid leukaemia grafted during their first relapse, the longest remission up to now being 390 days. One patient with chronic granulocytic leukaemia is still in second chronic phase after 360 days. Stem cells were transplanted early in the course of a T-lymphosarcoma, during complete remission; maintenance chemotherapy was withdrawn, and the chances of success of this treatment alone are being evaluated. The kinetics of blood and bone marrow CFU-c populations after transplantation were studied in 4 cases and were found to correlate closely with haematopoietic recovery following ablative bone marrow therapy. Stem cell transplantation can only be justified in acute leukaemia if it is carried out immediately after complete remission to consolidate the results and, hopefully, to prolong the remission.

An immunohistochemical and electron microscopy study has allowed us to find in a human thyroid cancer, follicle differentiation associating in a characteristic architectural pattern C cells, ciliated cells and follicular cells. Ultrastructural features were similar to those described in the normal adult Mouse thyroid by Wetzel and Wollman [1] and interpreted by them as a second type of thyroid follicle of ultimobranchial origin. The discovery of these structures within metastatic lymph nodes excludes normal thyroid follicle contamination. The presence of these neoplastic structures lead us to make the hypothesis of a stem cell of ultimobranchial and endodermal origin common to all the cells described.

The authors report a clinically typical case of trichopoliodystrophy (Menkes' disease) ; Neuropathological studies showed classical alterations, particularly irregular thickenings of Purkinje cell dendrites, and some less usual modifications : presence of an ectopic neuronal layer in the cerebellar molecular layer, suggestive of Obersteiner cells stopped in their progression ; normal appearance of myelin and elastic structures of systemic arteries. Ultrastructural studies showed some calcic concretions in mitochondria of hepatocytes and Purkinje cells, and lamellar structures in the cytoplasm of Purkinje cells, probably of ergastoplasmic origin. The activity of dopamine-beta-hydroxylase (DBH, or norepinephrine synthesising enzyme) and of phenylethanolamine - N-methyltransferase (PNMT, or epinephrine synthesising enzyme) was studied in 22 samples of brain stem. Activity was reduced in 3 samples, and increased in 4 : 6 of these 7 samples were from structures involved in cardiovascular and respiratory control. These results suggest the existence of a central vegetative neuropathy, which could explain the cardiovascular and respiratory disturbances sometimes reported in Menkes' disease ; but this neurochemical study gave no account of the sleep organization alterations of the patient.

An inhibitor of bone marrow stem cell (CFU-S) proliferation, prepared from fetal calf marrow, was administered to mice during sequential treatments with Cytosine Arabinoside. Results show that the percentage of CFU-S survival is significantly increased when the inhibitor is given simultaneously with the drug. A purified fraction of the inhibitor obtained by chromatography permitted survival of mice receiving lethal doses of Cytosine Arabinoside. The inhibit seems to be specific for CFU-S and has no effect on EMT6 tumor cells in vitro. Since it is not specific for the animal species, its clinical use could be envisaged to protect bone marrow during chemotherapy.

In the bronchi, the ultrastructural findings allow a schema to be established of proliferation-differentiation of basal cells, undifferentiated cells and mucus cells. In the bronchioles, the Clara cells or an immediate progenitor seem at the same time to play the role of stem cell for ciliated cells, mucus cells and brush cells. Same observations suggest that the bronchial and bronchiolar stem cells may produce neuro-secretary cells; the increase in neuro-secretary cells is a common enough phenomenon under the influence of numerous stimuli. No evidence of neuro-secretory cells dividing was observed. The histology and the kinetics of the cell population of bronchus associated lymphoid tissue (BALT) are reviewed. In the parenchyma, the role of the pneumocyte in restoring epithelial cells to high concentrations of oxygen is also discussed. Throughout the literature and also in the authors' experience, attention is drawn to the lack of correlation between the inflammation cell septal infiltrate and the endo-alveolar population. The cytokinetics of the alveolar macrophages (MA) are reviewed and recent findings discussed, including the absence of maintained cell division of the MA, the recruitment of young cells, the heterogenous distribution in the tissues of actively mitotic macrophages and the role of chemotactic factors.

The gonad of young Helix aspersa, studied by light and electron microscopy during the first post-hatching week, showed a compact structure. Eventually, a lumen appeared as the cells moved apart. The gonad was composed of stem and germinal cells. The latter cells were represented by primordial germ cells and oocytes. With our method of rearing, the female germinal line differentiated first.

Intratubular atypical germ cells are quite frequent in seminiferous tubules of tumor-free tissue adjacent to germ cell tumors of the adult testis. Atypical germ cells are considered by several authors to be totipotent stem cells for different types of germ cell tumors. If this theory is correct, atypical germ cells should be demonrable in the vicinity of germ cell tumors of children as well. We reviewed 30 testicular germ cell tumors of children aged 6 months to 6 1/2 years (17 yolk sac tumors and 13 mature teratomas). In five cases no tumor-free testicular tissue was present. In the remaining 25 cases - 15 patients with yolk sac tumors and 10 patients with mature teratomas - no atypical germ cells, neither intra-nor extratubular in location, could be found. The question arises, therefore, whether these so-called atypical germ cells are really the precursor cells of germ cell tumors or if they represent, at least in some cases, a reactive phenomenon due to the presence of a germ cell tumor.

The presence of a CSF activity in long term bone marrow cultures in Mice was not described until now. Using a double layer agar technique directly on the adherent layers of the cultures, a strong CSF activity is detected in these adherent layers, before recharging the cultures at the third week, or when the cultures are not recharged. The role of this activity in long term myelopoiesis maintenance in vitro is discussed.

Adult male rats received one injection (J0) of busulfan (10 mg/kg BW), which is specifically lethal for type A spermatogonia (Jackson and al., 1962). They were subsequently injected daily (J1 - J10) either with a proteinaceous extract of adult ram testis (10 mg of proteins/day) via the subcutaneous route, or with ram testicular fluid (1, 2 mg of protein/day), or with bovine serum albumin (1 mg/day) in order to analyse the resultant modification of the repopulation of seminiferous epithelium by the reserve stem cells (Clermont and Mauger, 1974). At the end of the treatments (J11), the number of type A spermatogonia per tubular cross section was significantly decreased in animals receiving testicular extract of fluid. The number of primary spermatocytes, from preleptotene up to zygotene stages were only diminished by testicular fluid supplementation. Ten days later (J20) the populations of primary spermatocytes, from preleptotene to pachytene stages derived from cells which were type A spermatogonia at the time of injections, were depleted. Type A spermatogonia were only decreased by testicular fluid treatment. Testicular fluid or extracts did not modify body weight nor the weights of other organs. A protein-like factor originating from the testis and present in the testicular fluid can thus modify the population of type A spermatogonia. Its action, however, is not specific for germ cells as Sertoli cells are affected by the administration of testicular extract in prepuberal rats (Hochereau-De-Reviers and Courot, 1978).

Burst forming units (BFU-E) from the blood of eight normal adults were grown in methylcellulose culture. Follow up of i and I antigens detected by an indirect immunofluorescence technique from the 9th to the 14th day of culture revealed that i antigen expression diminished while maturation proceeded. On the contrary 1 antigen expression increased meanwhile. Nevertheless, in addition to this maturation process, expression of i antigen must be determined by a regulatory mechanism operating during erythroid stem cell differentiation since a large proportion of immature erythroblasts at the 10th day of culture do not express i antigen.

96 patients with a dysmyelopoiesis have had an in vitro study of bone marrow CFUc at the time of diagnosis. A correlation between in vitro growth characteristics and the transformation in acute leukemia (AT) was searched. We found 5 types of in vitro growth: 3 with a "non-leukemic" pattern IA, IB, and IC, and 2 with a "leukemic" pattern II and III. In the type IA (normal growth) there is few death (16%), all without AT. In the types IB and ic with decreased in vitro growth, 40% of patients dead without an at and 25% after an AT. In the types II (with excess of clusters) and III (clusters without colonies) an AT was almost the case. The specificity, the positive and negative predictive values of in vitro growth type for the study of an AT outcome were the best of all that we obtained in the study of biological parameters in the dysmyelopoiesis. The study of bone marrow CFUc in dysmyelopoiesis can separate a group of patients with high risk of an AT outcome, which could be ameliorate with chimiotherapy.

In a case of Sezary syndrome with monoclonal serum immunoglobulin (IgM kappa) haematological investigations and a study of lymphocyte membrane markers failed to demonstrate any proliferation of B-lymphocytes. In order to test the hypothesis that the T-cells of Sezary syndrome and the B-cells producing the monoclonal immunoglobulin derived from the same stem cells and belonged to the same clone, an antiserum specific for the idiotype determinants of the IgM was used to detect by membrane immunofluorescence the possible presence in Sezary cells of surface receptors containing these determinants. The results were negative. The significance of the association--probably relatively too frequent to be fortuitous--between T-lymphocyte proliferation and monoclonal serum immunoglobulin therefore remains uncertain.

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.

We here report the results of our first attempts at fertilising the human oocyte in vitro. No external hormonal stimulation was used to induce follicular growth or maturation of the oocyte. Nine oocytes were obtained laparoscopically in ten women in the pre-ovulation hours. They were incubated in a synthetic culture medium in the presence of freshly ejaculated spermatozoa. Five oocytes were fertilised normally, of which three were cultured just up to the stage of 4-6 blastomeres. The three failures of fertilisation can be put down to poor quality of the gametes. The discussion is carried on about the quality of the oocyte and of the embryo and justifies further studies to deepen our knowledge before embarking on embryo transplant.

Alkaline phosphatase activity allows a certain discrimination between lympho-inhibition following a direct action on the lymphoid stem cells or a modification of mesenchyme/epithelium interactions; in this study we have compared the evolution of this activity in untreated chick embryos and in chick embryos following graft-versus-host-reactions. The important decrease of mesenchyme alkaline phosphatase activity induced here, involves a localisation of allograft reaction in this tissue; this result does not agree with the former explanations about a direct action on the lymphoid stem cells.