[Cryobiology of complex tissues].

Cooling biomaterials to liquid-nitrogen temperature is probably the most effective procedure for the preservation of their biochemical and morphological parameters, in so far as adverse effects of cooling are controlled. Potential damage has not the same explanation under different conditions of cold exposure. Even a moderate decrease of temperature leads to irreversible damage when applied to untreated organisms.

alpha-Interferon therapy for congenital dyserythropoiesis type I.

We report the case of a 28-year-old female followed for congenital dyserythropoiesis type I which required repeated transfusions. Alpha-2a interferon treatment was started because of post-transfusion chronic viral hepatitis type C. Following this treatment, haemoglobin level increased and reached normal value during the 24 weeks of interferon treatment.

Interest of simultaneous ultrastructural characterization of morphology, cytochemistry and immune phenotype in a case of putative hybrid acute leukaemia.

A case of acute leukaemia is reported in which blast cells expressed some B-related antigens (namely the CALLA antigen) and no peroxidase activity at the optical level; however, some mature granular cells contained Auer rods. Simultaneous characterization of ultrastructural morphology, cytochemistry and immune phenotype was performed. There was an apparent mutual exclusion in the expression of myeloperoxidase activity and the CALLA antigen, and a heterogeneity in the CALLA expression among the blastic population.

A paediatric case of sideroblastic anaemia. Ultrastructural studies of erythroblasts cultured from marrow BFU-E in a methylcellulose micromethod.

We examined the morphological and functional characteristics of erythroblasts derived from marrow erythroid progenitor cells grown in a methylcellulose microculture, which were taken from a female child with rare atypical sideroblastic anaemia (SA) partially responsive to pyridoxine. Colony formation was within the normal range in three successive cultures (median values: 82.25 CFU-E and 16.

[Arrangement of collagen fibers in the epiphyses and metaphyses of long bones in vertebrates].

The arrangement of collagene fibers in bone epiphyses and mataphyses form various species of reptiles and mammals was studied with a polarized light microscope and with a scanning electron microscope. In spite of the variety of shape observed in the long bone extremities of different species, the collagenic fibers arrangement in the bone epiphyses and metaphyses appeared constant. Even in reptiles known to lack a growth plate, the metaphyseal and epiphyseal fiber patterns evoked those observed in mammals.

[Biology of micro-vascularized cartilaginous transplantation in the growing dog].

Epiphyseal bone transplantations including growth area have been extensively studied experimentally in different animals and applied in children for several decades. Results were unpredictable and the amount of growth obtained with the graft could get 50 per cent of the normal. Development of microsurgical techniques has determined new possibilities of epiphyseal transfer with the respect of the epiphyseal vascularization.

Acute myeloid leukemia with giant inclusions: cytochemical and ultrastructural study.

Giant granules formation was investigated in myeloblasts of a patient with acute myelogenous leukemia by means of the combined techniques of peroxidase cytochemistry both in light and electron microscopy. Several pathologic features were noted: first an abnormal packaging of peroxidase in the peripheral area in large azurophilic granulations, second the progressive enlargement of huge vacuolar inclusions resulting from the interaction and fusion of large azurophilic granules with each other, with normal-sized primary granules and with cytoplasmic components. Microcrystalline structure could not be found in giant vacuoles no in vacuolar inclusions resembling Auer bodies.

Serum inhibitory effect on myeloperoxidase in human cancer.

The myeloperoxidase level is strongly depressed in leucocytes from cancer patients (-59%). Moreover sera of the same subjects induce a significant decrease in the myeloperoxidase activity of healthy subjects' leucocytes (-43%). We have found no convincing evidence of any correlation between the level of the inhibitory effect of sera and the tumour type.

[Viability criteria of islets of Langerhans isolated and purified using Ficoll].

Rejection of islet allografts is generally explained by immunologic problems, due to both cellular and antibody mechanisms. But another great problem is in the isolation of intact and viable islets of Langerhans: it is necessary to use a good method of pancreas distention, to determine the optimal concentration of collagenase for digestion, to select an effective technique for purifying the islets. This study correlates the morphology of isolated pancreatic islets of rats and dogs with secretion of insulin.

Decontamination of bacterial infection of monolayer cultures with a specific bacteriophage.

A few cell lines and primary monolayer cultures were accidentally infected by bacteria. These cultures were successfully decontaminated by means of the specific bacteriophage virus after quick identification of the responsible bacteria. This method presents a practical interest for preservation of valuable cultures.

[Presence of cell fusions in human malignant glioma].

The observation in malignant glioma of multinucleated cells possessing nuclei at different stages of the cell cycle, micrographs never encountered in benign glioma, led us to propose the hypothesis that, at least in this series of tumors, cell fusion was a criterion of malignancy. We tried to confirm this hypothesis by grafting malignant human gliomas into the brains of new-born mice for the purpose of making hybrid cells possessing human and murine characteristics conspicuous, we found these same multinucleated cells in these grafts. We demonstrated the hybrid nature of these cells by means of a fluorochrome, 33,258 Hoechst, which has the property of fixing itself selectively in the chromocentres of mice.

[Heterotransplantation of human glioblastoma in the brain of newborn mice].

7 human multiform glioblastoma have been transplanted into the brain of 100 new born Mice. Electron microscopy and chromosome analysis confirm the growth of a human tumor showing malignant features of glioblastoma.