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E B Mechetner

Publications and source records attributed to E B Mechetner.

At least 37 records · Page 2Linked to original sources
PubMed1991

Determination of boron in tissues and cells using direct-current plasma atomic emission spectroscopy.

We have developed a safe, simple, and efficient method for boron determination by means of direct-current plasma atomic emission spectroscopy. Tissues were solubilized by using concentrated sulfuric acid and 70% hydrogen peroxide to digest the samples without the need of high temperatures and pressures. Boron cluster compounds could be measured with sensitivity, precision, and accuracy similar to those of boric acid standards. Results obtained with [(C2H5)3NH]2B12H12, Cs2B12H11SH.H2O, and C15H32B10O6 show that this analytical method is applicable to a variety of compounds with different chemical structures. A sensitivity of 0.1 ppm has been obtained with known standards alone and in a variety of tissue matrices including tumor, blood, liver, skin, and cell suspensions. The measurement of total boron by direct-current plasma atomic emission spectroscopy (DCP-AES) has been achieved with as little as 50 mg of tissue or as few as 5 x 10(7) cells. The procedure is applicable to the analysis of boron in the ppm range with a high degree of precision and accuracy.

Animals↗
PubMed1991

Heterogeneity of peripheral blood reticulocytes: a flow cytometric analysis with monoclonal antibody HAE9 and thiazole orange.

The expression of a human erythroid cell surface antigen recognized by monoclonal antibody (mAB) HAE9 has been studied on peripheral blood reticulocytes by one- and two-color flow cytometry. Total reticulocyte count was determined using Thiazole Orange (TO) and flow cytometry. In normal individuals, 4.56% of reticulocytes were stained by FITC-labeled mAB HAE9. The correlation between reticulocyte percentage by TO and HAE9 staining was 0.828 (P less than 0.0001) in patients with hematocrits less than 0.25. A HAE9-positive reticulocyte percentage of 6-44% was observed when analyzed by two-color flow cytometry with TO and mAB HAE9. These findings, in conjunction with previous studies, suggest that mAB HAE9 recognizes an early, less differentiated population of peripheral blood reticulocytes. Enumeration of immature reticulocytes may be of clinical utility.

Antibodies, Monoclonal↗
PubMed1991

[Monoclonal antibodies to human small-cell lung cancer].

Murine monoclonal antibodies to human small cell lung cancer (SCLC) have been developed and partially characterized. Primary hybridoma clones were screened in the indirect immunofluorescence assay (IFA) on alive H417 cells. Then five clones (IgG1, IgG2a, IgG3 and IgM) non-reactive with normal human bone marrow cells and positively reactive with SCLC tumors were selected. The H417.3 antibody is directed against 47-50kD surface antigens of H417 cells. The antibodies are supposed to be applied for the immunodetection of SCLC metastases to bone marrow and immunotoxin preparations.

Animals↗
PubMed1991

[Preparation and use of monoclonal antibodies against seal alkaline phosphatase].

Monoclonal antibodies (termed as APP.1 and related to subclass IgG1) against seal alkaline phosphatase, have been obtained. APP.1 did not influence the enzymatic activity of alkaline phosphatase. The dissociation constant for the APP.1 interaction with Greenland seal alkaline phosphatase was equal to 8.5 x 10(-10) M. It was found that APP.1 interact with intestinal isoenzymes of common and fur seal, calf and deer alkaline phosphatases. An APP.1 complex with seal alkaline phosphatase was obtained and successfully applied in immunoenzymatic analysis. The use of this complex made it possible to diminish the limit of detectability of antibodies against peptide fragments of HIV-1 and HIV-2 proteins. Moreover, this complex allowed the identification of cytokeratin-8 and vimentin in human kidney slices and embryonic fibroblast-like cells, respectively.

Alkaline Phosphatase↗
PubMed1989

Two different anti-erythroid monoclonal antibodies in immunodiagnosis of human leukemias: a comparative study.

To date, only anti-glycophorin-A monoclonal antibodies (MAbs) have been widely used as anti-erythroid probes in the diagnosis of leukemias. We have examined blood, bone-marrow and lymph-node samples from 474 patients, adults and children, with different hemopoietic malignancies, using a panel of MAbs including 2 anti-erythroid MAbs directed to glycophorin-A and an antigen of erythroblasts, Ag-Eb. MAb HAE9 directed against a human epitope of Ag-Eb has earlier been shown to be highly specific for immature erythroid cells. Of all the patients, 2.7% demonstrated glycophorin-A expression on blast cells, while anti-Ag-Eb MAb HAE9 reacted positively with cells from 6.0% of patients. Samples from 31 of 474 (6.5%) patients expressed one or both erythroid markers. Our results indicate that MAb HAE9 may be useful, in combination with anti-glycophorin-A MAbs, as an anti-erythroid probe for immunophenotyping human leukemias.

Adult↗
PubMed1987

[Determination of erythroid variants of human leukemias using monoclonal antibodies].

Expression of erythroid antigens identifying with the use of monoclonal antibodies (mab) HAE3 and HAE9 was studied in 333 patients with different types of hemoblastoses. Frequency of erythroid variants based on the reaction with mab was 5.7%. In 2.4% of cases erythroid markers were the only indication on the nature of leukemia. In 2.7% of cases the types of leukemia were accounted for as "mixed" ones, i.e. erythrolymphoid and erythromyeloid variants. Only in 0.6% of cases erythroid variant was detected by the morphological criteria.

Adult↗
PubMed1987

Identification of a human erythroid cell surface antigen by monoclonal antibody HAE9.

A noncytotoxic monoclonal antibody (IgM) HAE9 that selectively binds to 36% CFU-E and more than 90% nucleated erythroid cells in human bone marrow is described. This antibody recognizes a 70-kDa-membrane protein. It is suggested that HAE9 is directed to a human epitope of Ag-Eb, an interspecies mammalian erythroid-specific cell surface marker.

Antibodies, Monoclonal↗
PubMed1986

Elimination of murine erythroleukemic stem cells with a novel anti-erythroid antibody conjugated to ricin A-chain: a model for studies of bone-marrow transplantation therapy.

We have produced a rat monoclonal antibody (MAb) MAE15 (IgG), specific for murine erythroid cells, using a murine erythroid cell line as immunogen. This MAb specifically binds to the surface of normal and neoplastic murine erythroid cells. Murine mature erythrocytes and non-erythroid cells as well as rat and human erythroid and non-erythroid cells are not recognized by MAb MAE15. Immunoblotting analysis and mixed precipitation in agar gel showed MAb MAE15 to be specific for murine epitope of 69 kDa antigen of erythroblasts (Ag-Eb), an interspecies antigenic marker of nucleated red cells and reticulocytes. A conjugate (immunotoxin) was prepared, comprising ricin A-chain and MAb MAE15. The immunotoxin inhibited protein synthesis of murine erythroleukemic Ag-Eb-positive K-2 cells and completely inhibited (at the concentration of 2 X 10(-7) M) spleen colony formation by erythroleukemic stem cells of the Ag-Eb-positive RAL cell line. Approximately 35% of the murine normal stem-cell (CFU-S) population was not affected by the immunotoxin at the concentration of 2 X 10(-7) M. This experimental system may be a convenient model for studies of bone marrow transplantation therapy of erythroleukemias.

Animals↗
PubMed1986

[Human leukemias studied with monoclonal antibodies to erythroid cells].

Activity of monoclonal antibodies HAE3 and HAE9 specific for human erythroid cells to different leukemic cells is described. These monoclonals do not react with nonerythroid leukemic cells. HAE3 and HAE9 reactivities are similar to those of polyclonal monospecific antibodies against an antigen of erythroblasts--a surface antigenic marker of nucleated red cells and reticulocytes. Monoclonal antibodies HAE3 and HAE9 are proposed to be used in diagnosis of leukemias.

Animals↗
PubMed1985

[Identification of the forms of human leukemia using polyclonal antibodies to erythroblast antigen].

Using polyclonal antibodies to an interspecies antigen of erythroblasts (Ag-Eb) with a molecular weight 69 000 D this antigen was revealed by immunofluorescence on the cells of the peripheral blood of patients with erythroleukemias and, in several cases, in those with undifferentiated leukemias. The possibility was shown of using these antibodies as a diagnostic tool when studying erythroleukemias and acute undifferentiated leukemias.

Acute Disease↗
PubMed1982

[Transcription of globin gene in erythroid cells transformed by Rauscher virus].

The synthesis of globin mRNA in cultured murine erythroleukemic cells transformed by the Rauscher leukemia virus and in the spleen of mice with Rauscher erythroleukemia was studied. The content of globin RNA sequence was estimated by cDNA hybridization with increasing amounts of cytoplasmic and poly (A)-containing RNA Globin RNA was found in the spleen of mice with Rauscher erythroleukemia, its content in cytoplasmic RNA and poly (A)-containing RNA being 0.02% and 0.4%, respectively. By contrast, no globin RNA sequences were found in transformed cultured murine erythroleukemic cells, which can be a cause of altered hemoglobin synthesis in these cells.

Animals↗
PubMed1981

Growth of normal and tumour haemopoietic cells on glass coverslips in peritoneal cavity of mice. I. Characterization of colonies.

A method for cultivation of normal and tumour haemopoietic progenitor cells on glass coverslips inserted into the peritoneal cavity of mice is described. This technique is a modification of the method proposed by Seki (1973). Intraperitoneal injections of bone marrow cells into syngeneic mice led to the formation of erythroid, myeloid, megakaryocytic, mixed and non-identified colonies on the GC. The greatest number of erythroid colonies was seen on the 3rd-5th day after bone marrow cell injection. The majority (greater than 90%) of the erythroid colonies consisted of 16-80 benzidine-positive cells. When GC-bearing mice were rendered anaemic, the number of erythroid colonies sharply rose, whereas the number of myeloid colonies remained unaltered. The influence of irradiation on haemopoietic colony formation was also investigated. There was a linear relationship between the dose of bone marrow cells injected and the number of haemopoietic colonies formed. Areas of mono- and multilayer growth were observed on the GC. Haemopoietic colonies always occurred on a cell multilayer containing fibroblast-like cells and were never observed on a cell monolayer consisting of macrophage-like cells. When self-maintaining erythroleukaemic cells transformed by Rauscher leukaemia virus (RAL cell line) were cloned, GC tumour colonies formed not only on a multilayer but also on a monolayer. Erythroleukaemic K-2 cells, which were of the same origin as RAL cells and had undergone 500 passages in vitro, did not form colonies on the GC. The nature of haemopoietic progenitor cells (mainly erythroid) forming colonies on GC, the nature of cells providing the haemopoietic inductive microenvironment on GC, the direction of tumour progression in RAL and K-2 cells, as well as some possible applications of the GC colony assay are discussed.

Anemia↗
PubMed1981

[Effect of serum against hematopoietic stem cells (RAMBS) on self-maintaining cells of Rauscher erythroleukemia].

The spleen colony assay was used to study the effect of rabbit antimouse brain serum (RAMBS) on erythroleukemic colony-forming cells (ECFC). RAMBS was shown to specifically inactivate hemopoietic stem cells (CFU-S) and to have no influence on ECFC growth. Absorption of RAMBS by erythroleukemic cells did not inhibit its anti-CFU-S activity. It is suggested that CFU-S and ECFC differ in the antigenic spectrum.

Animals↗
PubMed1981

Growth of normal and tumour haemopoietic cells on glass coverslips in peritoneal cavity of mice. II. Immunological identification of bone marrow colony-forming cells.

The effect of rabbit anti-mouse brain serum and monospecific antibodies to an antigen of erythroblasts, Ag-Eb, on cells forming haemopoietic colonies on glass coverslips was studied. These colonies developed on the fibroblast-macrophage layer formed on glass coverslips which had been inserted into the peritoneal cavity of mice. when bone marrow cell suspensions were treated with RAMBS and the complement, or with anti-Ag-Eb antibodies plus complement, the CFU-GC colony-forming ability remained unaffected. In the examined cell suspensions, RAMBS inactivated 44% of CFU-S. When bone marrow cell suspensions were treated with anti-Ag-Eb antibodies, the number of immature erythroid cells was reduced to 75%. The CFU-GC are presumed to resemble the committed (unipotent) haemopoietic progenitor cells.

Animals↗