Cytogenetic analysis of mouse hybridoma producing monoclonal antibodies to diphtheria toxin and of its derivative, that lost secretory activity at the third passage in vivo, has been carried out. 58% cells of antibody secreting cell lines belonged to a modal class (76-79 chromosomes per cll). The modal chromosomal number of the subline that has stopped producing antibodies decreased to 63-66 per cell and the stem line of this derivative consisted of 30% of cell population only. Chromosome aberrations were much more frequent in hybridoma cells, that ceased to secrete antibodies, than in cells of original hybridoma: 32.3% of aberrant metaphases (1.38 break per cell) and 6.3% of aberrant metaphases (0.1 break per cell), respectively. Mycoplasma infection was found in the hybridoma subline that stopped producing antibodies as defined by the microbiological and cytochemical techniques. Mice might be the possible source of infection. By means of cloning of hybridoma variant, that did not secrete immunoglobulins, several sublines with the recovered secretory function were obtained.

Bone marrow trepanobiopsies were cultivated in the agar drop-liquid medium system. A total of 155 subjects with different diseases of the blood system and 31 controls were examined. It was shown that prolonged cultivation of trepanobiopsies makes it possible to functionally evaluate the stromal elements of the bone marrow. The whole medullary tissue is characterized by marked heterogeneity as regards its ability to synthesize humoral stimulants of granulomonocytopoiesis. The colony-stimulating ability (CSA) of this tissue combines the CSA of the hemopoietic and stromal cells. In bone marrow deficiency of varying degree, the function of the bone marrow stroma is highly activated. The trepanobiopsy areas short of the hemopoietic tissue possess a higher ability to form a monolayer on the dish surface. During AML and ALL relapses, the ability of the bone marrow stroma to synthesize the humoral stimulants is lowered, whereas the ability to form monolayers is less demonstrable. In diseases associated with the development of secondary fibrosis (CMF, CML, IP), the bone marrow stroma was discovered to be less capable of synthesizing the humoral stimulants, which provides evidence against the involvement of fibrous tissue in the formation of the total CSA of the bone marrow. It is assumed that fibroblasts and fatty cells are related histogenetically and that their proliferation is controlled by humoral factors.

The authors describe 4 families whose members showed myeloproliferative diseases. In one of the families, polycythemia vera (PV) was seen in twin brother and sister, in the other one, chronic myeloleukemia (CML) afflicted both daughter and mother, and in the two remaining families PV and CML afflicted two brothers and mother and daughter, respectively. It was established that neutrophil phosphatase activity was lowered not only in the afflicted brother but also in healthy members of the third family. Based on the reported and their own data the authors arrive at the conclusion that familial myeloproliferative diseases occur in rare cases. In all the cases of familial myeloproliferative diseases, the transmission of the illness by heredity was discovered to be impossible. It was also ascertained that transmitted by heredity are only those cell deficiencies of the tissues that later on will be afflicted by leukemia or will develop immunodeficiency manifested by increased mutation of the myelopoietic cells (DNA repair deficiencies) or by inability to eliminate the leukemic cells.

Electron microscopy was applied to study and compare blast cells in 7 patients with acute myeloblastic, 4 with acute monoblastic and 11 patients with acute myelomonoblastic leukemias. Three morphological types of blast cells are described for acute myeloblastic leukemia and 2 types of blast cells for acute monoblastic leukemia. In acute myelomonoblastic leukemia, no specific cells characteristic but for this disease pattern were detected while the main tumor substrate included the different types of blast cells described for acute myeloblastic and monoblastic leukemias. A patients also manifests the predominance of the same type of blast cells, with no combination of different types. Ultrastructure of blast cells in acute non-lymphoblastic leukemias and therapeutic approaches are discussed.

The human leukemia K562 cells differentiation is studied in diffusion chambers implanted in rats intraperitoneally. The investigations revealed the possibility of explantation of leukemic K562 cells in diffusion chambers in a heterogeneous host. The ability of these cells to follow the myeloid lineage of differentiation is shown.

The expression of Fc-receptors to immunoglobulins IgG, IgA, IgM, that of FcH-receptor and receptors to C3-components of the complement in peripheral blood blast cells were studied in 11 patients with acute myeloblast leukosis and 10 patients with chronic granulocytic leukemia at the stage of blast transformation. The data obtained show the lower level of differentiation and functional activity of blast cells in patients with acute myeloblast leukemia while in chronic granulocytic leukemia a degree of expression of surface receptor on myeloblasts is close to the data obtained in the study of membrane receptors on promyelocytes and myelocytes of healthy persons.

Colony- and cluster-forming ability of bone marrow cells in agar medium was studied in 6 healthy children and 13 children suffering from acute leukosis. During acute stages of the diseases colonies and clusters in agar medium consisted of granulocytic cells and their quantity depended on the safety of predecessors of bone marrow granulopoiesis. In contrast to acute lymphoblastic leucosis, acute myeloblastic leucosis is characterized by a sharp growth of cluster-forming and a less intensive growth of colony-forming ability of hemopoietic cells. The bone marrow remission is marked by the growth of diffusive and mixed colonies and clusters, consisting of granulomonocytic elements. The low level of colony- and cluster-formation in the medium at the last stage of therapy (induction of acute leukosis remission) correlated well with positive indices of treatment effectiveness. The results obtained during the cultivation of blood-forming cells in the agar medium may be also used for diagnosis and prognosis.

Ultrastructure of the epithelial components of mammary carcinoma is well studied; detection of the organ and tissue specific features enables the differential diagnostics with tumours of different histogenesis both in the metastatic nodes and in the mammary tumour tissue. Moreover, establishing a certain complex of the electron microscopic features for separate histological variants of mammary carcinoma favours the differential diagnostics between them. Including the ultracytochemical methods into the investigation complex will give an opportunity to clarify the role of some enzymes in he tumour growth. A detailed study of the mammary carcinoma stromal component will help in determining the function of tumour tissue.

Ultrastructural analysis of 9 monophasic spindle-cell synovial sarcomas revealed both undifferentiated tumour cells and histiocyte-like and fibroblast-like elements. Specialized contacts between tumour cells are found in 8 tumours, formation of the cavities of varying size (including vessel-like structure in 2 cases) in 7 tumours. Other findings included a discontinuous external lamina in 4 tumours; filopodium-like cell protrusions in 5, and spindle-shaped collagen bundles with long striation in 2 cases. The observation of cell contacts and cavities is of a diagnostic importance for monophasic synovial sarcoma. The differential diagnosis of these sarcomas and other spindle-cell tumours is discussed. Ultrastructural findings are interpreted as evidence of the monophasic spindle-cell synovial sarcoma origin from mesenchymal stem cells.

The effect of some carcinogenic and non-carcinogenic agents on the content of CFUs and frequency of micronuclei (Howell-Jolly corps) in polychromatic erythrocytes of bone marrow cells was studied in CBA mice. Benzene administration decreased the content of CFUs in bone marrow cells, but this effect is considered to be rather a sign of its hematotropic than carcinogenic action. Changes in the CFUs amount induced by chrysotile-asbestos and quartz DQ-12 action were insignificant. All investigated carcinogenic agents (benz(a)pyrene, asbestos and benzene) significantly increased the number of micronuclei in polychromatic erythrocytes of bone marrow in mice.

Both most common and rare varieties of uterine cervix carcinoma were studied light and electron microscopically. It is shown that tumours histologically classified as squamous-cell carcinoma originate either from the squamous epithelium of the ectocervix or from the metaplastic epithelium. Characteristic ultrastructural features of these histogenetic variants of squamous-cell carcinoma are described. The authors' and literature data are presented indicating that the great histological variety of adenocarcinomas and glandular-squamous carcinomas is due to the pluripotential properties of proliferating stem cells capable of forming glandular, solid and squamous-cell structures. The source of clear-cell adenocarcinoma may be not only Gartner's duct but the mullerian epithelium as well. The classification of uterine cervix carcinomas reflecting their histogenesis is proposed.

The influence of transplantable tumour on migration, proliferation and differentiation of haemopoietic stem cells was studied. It is shown that in the initial period of tumour development the migration and proliferation of stem cells intensify. In the final stage of the tumour growth the quantity of haemopoietic stem cells decreases considerably in the bone marrow, spleen, and peripheral blood. It is established that during the tumour growth the differentiation of stem cells from the spleen changed towards erythropoiesis.

Cholinacetyltransferase (ChAT) activity has been studied in 56 nuclei of the cerebral trunk in human fetuses at the age of 6-8 lunar months. Cytoplasmic and synaptic ChAT activity has been revealed and three types of neurons for cholinergic synaptic transmission has been distinguished. There are only cholinergic-noncholinoceptive neurons in five macrocellular nuclei of the cranial nerves. In 25 nuclei (paravicellular, reticular, pigmented, sensitive nuclei of the cranial nerves, nuclei of the funiculi posterior and some other switching centres) there are only noncholinergic-cholinoceptive neural cells. In 16 nuclei there are three, and in 8 nuclei--two types of cells. Either noncholinergic-cholinoceptive or cholinergic-noncholinoceptive cells predominate; there is no predominance of cholinergic-cholinoceptive neurons in any of the nuclei. Mapping on the position of the cholinergic synaptic transmission neurons in the cerebral trunk is composed.

Genome mutation frequencies (GMF) were determined in cells of endogenous (from bone marrow) and exogenous (from bone marrow, spleen and embryonic liver) spleen colonies on the basis of variations in DNA contents of interphase nuclei. In cells of the former GMF varied from 1.1 X 10(-2) to 10.8 X 10(-2), and in the latter these were equal to 8.9 X 10(-2). In the cells of exogenous colonies derived from X-irradiated precursors (1.8 and 5.9 Gy) GMF were 10.1 X 10(-2) and 11.9 X 10(-2), resp. The mode of transplantation influenced greatly on the GMF: after an additional short transplantation (4-6 days) the number of GMF increased by 1.5-2 times. It is concluded that the increased number of GMF may be responsible for the limited life-span of bone marrow stem cells in the course of their serial transplantations in the irradiated syngenic mice.