We found that hydrolysates of poly(A)RNA from Ehrlich ascites carcinoma cells which were transcribed by RNA polymerase III contained an unusual component designated as X. It was part of B2 RNA representing a transcript of B2 retroposon, typical of rodents. The component X possesses a cap-like structure, xPPP5'G, where x has al non-nucleotide structure. About half of all B2 RNAs contained this group at the 5'-end. Previously, Epstein et al. (Epstein P., Reddy R., Henning D., Busch H. parallel J. Biol. Chem. 1980. V. 255. P. 8901-8906) detected a similar structure at the 5'-end of small nuclear U6RNA. Later, Singh and Reddy (Singh R., Reddy R. parallel Proc. Natl. Acad. Sci. USA. 1989. V. 86. P. 8280-8283) showed methyl to be the blocking group in the component X of U6RNA. Besides B2 RNA, we found 5'-ends containing methyl groups in 7S K-RNA.

A cytochemical technique with silver nitrate staining was used to study the nucleolar organizer activity in metaphase spread of bone marrow cells from 13 patients with acute lymphocytic leukemia (ALL), 11 patients with chronic myelogenous leukemia (CML), 7 patients with acute myelogenous leukemia (AML), and 4 normal persons. Additionally, computer-assisted image analysis was used to quantitate the amount of silver staining in interphase nuclei of bone marrow cells from 6 untreated ALL patients, 3 normal subjects and 1 bone-marrow-transplant recipient. The results obtained have indicated that the nucleolar organizer reactivity (NOR) is significantly lower in the control group than that in ALL patients. NOR activity level is significantly lower in both CML patients in chronic phase, and AML patients than in the ALL group, and is similar to that in the control group. When the data obtained for the interphase nuclei were compared with those obtained for the metaphase spread, a strong correlation was recorded between the fraction of bone-marrow metaphases stained positively with silver, the average number of silver-positive nucleolar organizer regions per metaphase, and the amount of silver staining in the interphase nuclei. Silver staining used for the detection of these disease-related differences in NOR activity can serve as a diagnostic procedure in evaluating human leukemias. The computer-assisted image analysis of bone marrow cell interphase nuclei would be useful for more accurate resolving biological and medical problems.

The activity of nucleolar organizer (NO) in megakaryocytes (MG) from 8 donors, 10 patients with immune thrombocytopenias (IT), 17 patients with chronic myelocytic leukemia (CML) and 14 patients with multiple myeloma (MM) was studied by silver staining. The average number of nucleoli in MG of normal donors comprised 21.8 per nucleus with a range from 16.6 to 33.7. It was significantly lower in MG of CML patients, and, on the contrary, it was higher in MG of IT patients. The average number of Ag grains per nucleus reflecting their activity in relation to ribosomal RNA synthesis was found to be the highest (127 +/- 32.1) in MG of IT patients but rather low (43.2 +/- 7.2) in CML patients as compared to those of the control (76.5 +/- 11.1) and MM patients (86.0 +/- 5.6). The differences in the functional state of MG in varying diseases as well as possibilities of using this new approach in hematology have been discussed.

The ultrastructural organization and the state of silver-staining nucleoli (Ag-NOR) of peripheral blood and bone marrow lymphoblasts of 10 patients with acute lymphoblastic leukemia (ALL) were studied in the complex with the biochemical assay of the ribosomal levels in the cellular cytoplasm of these patients. In the majority of the patients investigated the morphological picture of the nucleolus and the character of Ag-NOR have evidenced the high functional activity of pRNA-synthesizing apparatus and correlated with the high ribosomal level in the cytoplasm of the cells studied. Significant accumulation of granular components (RNP-particles) in the nucleoli of the lymphoblasts, reflecting disorders in their transport from nucleus to cytoplasm, were detected only in 2 patients.

A case of hairy-cell leukemia (HCL) has been described in which the cells of the pathological clone in the course of time lost their surface immunoglobulins and retained membrane markers associated with the T-lymphoid series. It has been suggested that this change in the immunological phenotype of the cells may lead to an erroneous diagnosis of T-cell HCL.

Rat organospecific transplantable RA-2 rhabdomyosarcoma strains RA-2H and RA-2L were investigated using single cell cloning technique for "Micronuclear containing cell frequency" (MCF) and "Metastatic potential" (MP). The RA-2H was obtained from RA-2 during selection for increasing metastatic potential, whereas the RA-2L was the result of selection in opposite direction. MP was assessed by lung colony formation technique and in the case of RA-2H, it was one hundred times greater than in the case of RA-2L (2490 +/- 280 and 22 +/- 11 lung colonies i.v. after injection of 10 cells, respectively). Average MCE for RA-2H was 3 and for RA-2L 5.3%. Also, significant differences were observed between these substrains in percentage of anaphase and telophase cells with bridges and fragments (24 +/- 4 for RA-2H and 56 +/- 5% for RA-2L, P less than 0.05). The selection of RA-2H clones with high level of MCF was successful. In the population obtained MCF was increased up to 7.8% and MP decreased (79 +/- 44). So, the selection for decreasing of MP led to significant increase in genome instability characteristics and the selection for increasing of MCF--to the abrupt decline of MP, which proved the existence of negative correlation between these two characters in populations studied. It is concluded that correlation between malignancy and genome instability in tumor populations with different levels of malignancy is not, as a rule, positive.

Clinical possibilities of using monoclonal antibodies (MCA) in the immunodiagnosis of malignant neoplasms have been analysed. Certain Soviet and foreign MCA to tumor-associated antigens have been characterized, and their clinical importance has been estimated. A special attention has been paid to MCA against "cross", i.e. leukemia-associated, antigens. Basing on the data obtained it has been established that the use of even two MCA series (ICO-10 and ICO-20) makes available sufficiently accurate information on the tumor histogenesis. Besides that, MCA ICO-63, HNK-1, ICO-10, ICO-46 can be used for immunophenotyping of some solid tumors, particularly, for the immunophenotyping of human neuroblastoma cells.

Three new human cervical carcinoma xenografts was established from clinical tumor specimens of patients with I-II stages of disease. Growth characteristics of models are writing. Xenografts designated CC 9, 24 and 25 contain integrated DNA HPV, complemented DNA HPV-16. DNA CC 5 contain neither DNA HPV-16, nor DNA HPV-18.

A case of radiation-induced leukemia has been described in a woman living in the area exposed to radioactive contamination as a result of the disaster at the Chernobyl NPS. Radiation-induced leukemia was diagnosed basing on the cytogenetic changes in the bone marrow and peripheral blood lymphocytes. Cytogenetic changes in the peripheral blood lymphocytes have been recorded in 60 subjects who were evacuated from areas contaminated with isotopes as a result of the disaster.

Proviral integration of a simian T-cell leukemia virus, S(H)TLV-I, highly homologous to human T-cell leukemia virus type 1 was examined in cellular DNAs isolated from lymphoid organs of lymphomatous and healthy baboons from the Sukhumi monkey colony. Most of the sick and some of healthy monkeys contained HTLV-I-related sequences in their chromosomal DNAs. Judging from the integration site of the provirus genome, S(H)TLV-I-infected cells had selective preferences and proliferated monoclonally.

A highly purified thyroglobulin mRNA was isolated from human nodal euthyroid goiter. A full-length cDNA was synthesized from 33S RNA by using reverse transcriptase in the presence of human placenta ribonuclease inhibitor. A DNA complementary to human Tg mRNA was used in liquid hybridization experiments to quantify Tg mRNA. The amount of Tg mRNA in euthyroid nodal and congenital goiter was reduced. In thyroid cancer Tg specific mRNA was absent. Direct correlation between Tg gene expression in thyroid cells and DNAase-I hypersensitivity of chromatin from the thyroid gland nucleus was revealed.

Human corneal endothelial cells (HCEC) were transfected with some cloned oncogenes. The direct microinjection of either early region (E1) genes of monkey (SA7) and human (Ad5) adenoviruses or Ha-ras oncogen in conjunction with the Ad5 Ela-gene into embryonic HCEC nuclei was shown to result in immortalization of these cells. 3 independent immortalized HCEC lines were established in their growth and morphological properties were studied. These properties were very similar to those of primary HCEC, but unlike primary HCEC the immortalized cells didn't need the endothelial cell growth factor.