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N Mamaev

Publications and source records attributed to N Mamaev.

6 recordsLinked to original sources
PubMed1998

Age related decrease of NOR activity in bone marrow metaphase chromosomes from healthy individuals.

AIMS: To present data obtained from human bone marrow preparations from healthy individual showing that the proportion of metaphases with silver stained nucleolar organiser region (AgNOR) chromosomes is associated with the age of the donor. METHODS: Bone marrow preparations from eight Russian and 10 Argentinian healthy individuals donating bone marrow for heterologous transplantation were studied by silver staining. The Russian bone marrow preparations were used directly, while the bone marrow specimens from Argentinian donors were incubated for 24 hours at 37 degrees C in F-10 medium with 15% fetal bovine serum. The slides were silver stained by the one step method of Howell and Black with slight modifications. Thirty metaphases with clearly defined D and G group chromosomes were scored for the numbers of AgNORs. All metaphases that were adjacent to silver stained interphase nuclei were analysed to assess the percentage of AgNOR positive mitoses. The Kruskal Wallis test and Kendall's rank correlation coefficient (rK) were used to assess the relation between age and the percentage of AgNOR positive cells. RESULTS: The mean numbers (SE) of AgNORs per metaphase were 5.06 (0.17) and 5.56 (0.23) for the Russian and Argentinian groups, respectively, with no significant differences between the two groups. The common percentage of AgNOR positive cells decreased significantly as a function of age, with an rK = -0.57 (p < 0.0012). CONCLUSIONS: The percentages of AgNOR negative metaphases in bone marrow from healthy individuals is strongly associated with age and this may be related to age related telomere loss.

Adolescent↗
PubMed1991

AgNOR staining in benign hyperplasia and carcinoma of the prostate.

We have modified existing techniques for silver staining of nucleolar organizer regions of intact interphase cells by hypotonic swelling and by formic acid treatment to reduce background staining. This allowed the microscopic identification and counting of individual AgNORs in the nucleoli. The method was used on nine adenomatous prostatic samples (including one of normal prostate tissue outside a localized tumor) and on seven prostatic adenocarcinomas. In general, the adenomatous samples displayed fewer AgNORs (mean 13 dots/cell) than did the carcinomas (mean 24 dots/cell). Although no cells with very high AgNOR counts were found in specimens from nonmalignant tumors, two of the adenomatous prostates did have AgNOR profiles that to a large extent overlapped with those of carcinomas. A highly differentiated carcinoma (of which only very small amounts were present in the sample) had low AgNOR counts. The three moderately differentiated carcinomas had more silver-positive material than the nonmalignant prostates but less than the three poorly differentiated carcinomas. The latter tumors also had a substantial proportion of cells with greater than 60 AgNOR counts, something that was never seen in carcinomas with higher differentiation. The data indicate that analysis of silver staining-positive material in intact interphase cells may help distinguish between benign and malignant prostatic tumors and between highly malignant and low malignant carcinomas.

Adenocarcinoma↗
PubMed1988

Morphofunctional characteristics of silver-stained nucleoli of tumor cells in a patient with dimorphous pulmonary carcinoma.

The first detailed description of morphofunctional characteristics of silver-stained nucleoli of tumor cells in a patient with dimorphous pulmonary carcinoma is presented. The article deals with the problems of heterogeneity of tumor cells in respect to nucleolus apparatus. Possible mechanisms that underlie the enlargement of nucleoli of tumor cells and activation of their ribosomal DNA are discussed.

Adult↗
PubMed1985

The activity of nucleolar organizer regions of human bone marrow cells studied with silver staining. I. Chronic myelocytic leukemia.

The activity of nucleolar organizer regions (NORs) in chromosomes and interphase nuclei of bone marrow (BM) cells from 21 patients with chronic myelocytic leukemia (CML), including seven patients at the time of blastic crisis (BC), has been studied with silver nitrate staining. The average numbers of Ag-NOR per metaphase in PHA-stimulated peripheral blood lymphocytes from patients with CML and normal individuals were 7.1 +/- 0.3 and 7.4 +/- 0.1, respectively, indicating no statistical difference between them. Those in BM cells from patients with CML, as in the normal donors, were more heterogeneous compared to PHA-stimulated lymphocytes, and most of the metaphases (up to 67%) did not contain silver-stained NORs. The average number of Ag-positive NORs in BM mitoses from untreated patients in the chronic phases of CML and from those in the BC were similar (4.9 +/- 0.3 and 4.8 +/- 0.4, respectively). As for NORs of the Ph chromosome, they were Ag-positive in the majority of patients, including 9 of 14 in the chronic phase and 3 of 7 in the BC. This article contains some data in support of the authors' previous assumption regarding the correlation between BM Ag-NOR patterns and the degree of maturity of the cells tested in mitosis.

Adolescent↗
PubMed1985

Two cases of acute myeloblastic leukemia (M2 type) with karyotypes 45X,-X,t(6;8)(q27;q22),inv(9) and 46,XY,t(8;21)(q22;q22),del(9)(q22).

Two patients with acute myelogenous leukemia (AML) are described. The first case is that of a patient with AML who had a low leukocyte alkaline phosphatase level associated with a variant (6;8)(q27;q22) translocation, coupled with loss of an X chromosome in bone marrow and unstimulated blood cells. The second case is that of an AML patient in whom the karyotype of the leukemic cells at the time of diagnosis was 46,XY,t(8;21)(q22;q22),del(9)(q22); at relapse, the patient acquired an additional chromosome #19. The lack of involvement of chromosome #21 in the first case, as well as the occurrence of an abnormality of chromosome #9, in addition to the t(8q-;21q+) in the second case are discussed with reference to the character of the possible specific chromosomal events in patients with type M2 AML.

Adult↗