Identification of protein complexes containing the c-rel proto-oncogene product in avian hematopoietic cells.

The c-rel proto-oncogene product has been identified as a 75 kDa protein expressed in lymphoid cells transformed by REV-T and Marek's disease virus. A 4.0 kb c-rel transcript is expressed in the bursa, spleen and thymus of chickens with highest levels of expression at 10 days post hatch. Using antiserum specific for the v-rel oncogene product, P75c-rel has been precipitated from [35S]methionine-labeled extracts of bursal, splenic and thymic lymphocytes. Additionally, proteins with the molecular mass of 40 kDa, 115 kDa, and 124 kDa co-immunoprecipitate. These proteins co-migrate with the proteins found associated with pp59v-rel in REV-T transformed lymphoid cells. Antiserum specific for pp40, the most abundant cellular protein associated with pp59v-rel, co-precipitates p75c-rel verifying the existence of p75c-rel/pp40 complexes in normal avian lymphocytes. Antiserum directed against the amino-terminal region of pp59v-rel fails to precipitate native p75c-rel complexes from normal lymphoid cells. In the presence of ionic detergents, antisera directed against the amino, middle and carboxy-regions precipitate equivalent amounts of p75v-rel. These results suggest that the amino-terminal region of p75c-rel is active in binding other proteins or is inaccessible to the antiserum due to the conformation of p75c-rel in the complex. Two p75c-rel complexes exist in the cytosol of normal lymphocytes. The most abundant complex contains 60% of the p75c-rel associated with p115 and p124. The remaining p75c-rel is associated with pp40.

Effects of recombinant human erythropoietin on the haemopoietic bone marrow monitored by magnetic resonance spectroscopy in patients with end-stage renal disease.

Volume selective magnetic resonance (MR) proton spectroscopy was used to investigate changes in the haemopoietic bone marrow in patients with end-stage renal disease undergoing treatment with recombinant human erythropoietin (rHuEPO). Significant changes could be detected in the spectra 14 days after the beginning of treatment, before any response was seen in the haemoglobin concentration of peripheral blood. The spectral changes indicate an alteration in cellular composition of haemopoietic bone marrow with an increase in the amount of haemopoietic active tissue. One patient showed a major change in the spectrum four days after treatment began, indicating that MR spectroscopy may detect early changes in the cellular composition of the bone marrow. This noninvasive method may be useful in evaluating treatment effects of recombinant human haemopoietic growth factors in the bone marrow, as well as investigating bone marrow response from different modes of rHuEPO administration.

Flow cytometric detection of beta-globin mRNA in murine haemopoietic tissues using fluorescent in situ hybridization.

The novel method for flow cytometric detection of cellular RNA species in suspended cells by fluorescent in situ hybridization (FC-FISH) was applied in the evaluation of beta-globin expression in murine haemopoietic tissues. Normal murine bone marrow cells and regenerating bone marrow cells obtained after lethal irradiation and bone marrow transplantation as well as murine 15 d fetal liver were examined. Furthermore, spleens and bone marrow of phenylhydrazine-induced anaemic mice were studied. Biotinylated sense- and antisense single strand RNA probes, obtained by transcription of a 510 nucleotides murine beta-globin cDNA sequence subcloned into the pGEM1 plasmid were used as hybridization probes. For detection of the hybrids formed, avidin-FITC was used. Only the antisense beta-globin probe gave strongly positive fluorescence signals in a defined population of cells in each of the tissues examined, whereas the sense probe did not give signals higher than control samples. Melting characteristics of the hybrids showed the specificity of the in situ hybridization reaction. Forward light scatter distributions, reflecting cell size of the positive cells were as expected from erythroid cells. Within the erythrocyte subpopulation both beta-globin-negative and -positive cells were detected. The percentages of positive cells determined flow cytometrically correlated with the percentages observed in May-Grünwald/Giemsa stained preparations. Differences observed in fluorescence intensity between positive cells of different organs were no larger than about a factor of two, indicating a rather constant beta-globin mRNA content over the entire differentiation range. An exception was 15 d fetal liver, which was shown biochemically to contain about eight times more beta-globin RNA and which had a 2.4 times higher fluorescence intensity. We estimate that the sensitivity of the present method is such that as little as 500 copies per cell of a specific mRNA of 1 kb length would be detectable.

Characterization of bcr gene products in hematopoietic cells.

The bcr gene plays a critical role in the pathogenesis of two human leukemias associated with the Philadelphia chromosome: chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL). In both instances a chimeric gene, formed between bcr and the abl protooncogene, results in expression of fused bcr-abl proteins with tyrosine kinase activity. There is controversy regarding the normal gene products of bcr. We investigated this problem by several techniques and found proteins of 190/185, 155, 135, 125, 108, 83 and 47 kDa in several human cell lines by immunoprecipitation with two distinct site-directed anti-bcr antibodies termed anti-bcr(738-753) and anti-bcr(898-911). The 190/185, 155, 125 and 108 kDa proteins were consistently detected by anti-bcr(898-911) antibodies by immunoblotting. Antibodies pre-reacted with excess bcr peptide did not detect these proteins. These proteins were labeled with [32P]orthophosphate in vivo and in vitro by [gamma 32P]ATP in immune complex kinase assays performed with anti-bcr antibodies indicating that these proteins are phosphorproteins. Following labeling in kinase assays, phosphoamino acid analyses detected both phosphoserine and phosphothreonine. In structural studies using one dimensional peptide maps derived by partial V8 protease treatment, the 185, 155, 135, 125 and 108 kDa proteins shared several peptide fragments but contained unique fragments as well. Similarly 2-dimensional maps of proteins labeled in the kinase assay exhaustively digested with trypsin, revealed homology between the 155, 135, 125, 108, and 83 kDa proteins. bcr proteins sedimented in glycerol gradients as putative complexes detected in the cytoplasm of the cell. A 47 kDa protein as well as the recently identified Ph-P53 protein appeared to be associated with bcr proteins based on their co-sedimentation in glycerol gradients and co-immunoprecipitation with several different anti-bcr antibodies. None of the proteins exhibited a precursor-product relationship in pulse-chase experiments conducted with [35S]methionine. We conclude that human cells express several different bcr gene products ranging in size from 190 to 83 kDa, and that these proteins can form specific intracellular cytoplasmic complexes with other cellular proteins.

Determination of amsacrine in human nucleated hematopoietic cells.

A new method has been developed for the determination of amsacrine (AMSA) in human nucleated hematopoietic cells. In order to prevent efflux during the cell separation procedure, white blood cells (WBCs) were separated from red blood cells by dextran sedimentation, leaving the WBCs in their natural environment. After cell counting, pelletting the cell suspension and correcting for the admixture of supernatant, AMSA was extracted from the WBCs and determined by high-performance liquid chromatography. Linearity of extraction was observed up to 40.10(6) cells. The inter-assay variation was 4.7%. Plasma and cellular concentrations were measured in five patients at the end of a 3-h infusion of 100 mg/m2 AMSA. A pharmacokinetic study of plasma and cellular AMSA concentrations up to 19 h after infusion was carried out. AMSA concentrations in WBCs correlated well with the plasma levels (n = 20, r = 0.967) with an accumulation factor compared to the plasma concentration of 2.6-9.8 in the patients studied. The method described is useful for studying cellular pharmacokinetics of AMSA in man.

Benzenismo: subsídios para a identificaçäo de grupos ocupacionais de mais elevado risco de exposiçäo / Benzenism: allowance for identifications of occupational groups of high risk of exposure

Após breve revisäo da literatura científica sobre benzeno e doença, particularmente quanto aos efeitos da exposiçäo a longo prazo sobre o sistema hematopoiético, säo descritos os principais aspectos de sua produçäo e utilizaçäo. Quanto à produçäo, é destacada a importância quantitativa do benzeno produzido a partir do petróleo, ou seja, cerca de 92% da produçäo total. A distribuiçäo do consumo do benzeno näo guarda correlaçäo com a distribuiçäo do risco potencial para a saúde de trabalhadores. Assim, embora 95% da demanda do benzeno destine-se à indústria química de base, como matéria-prima para síntese, e apenas 5% da demanda destine-se às suas aplicaçöes como solvente ou diluente, é nos trabalhadores ligados à fabricaçäo e/ou aplicaçäo de tintas, vernizes, "thiners", colas e adesivos que devem se situar o foco de preocupaçäo, pelos riscos à saúde, principalmente nas exposiçöes a longo prazo. Por último, descrevem-se a produçäo e o consumo de benzeno em nosso país, mostrando o acelerado crescimento e a expansäo da populaçäo potencialmente exposta a este hidrocarboneto aromático tóxico

Benzenismo experimental / Experimental benzinism

Foram estudadas as alteraçöes do sangue periférico, medula óssea e baço de camundongos da raça suiça, que receberam injeçöes subcutâneas de 2 ml/kg de benzeno, 3 vezes por semana, em dias alternados, durante 20 semanas. A concentraçäo de hemoglobina, número de leucócitos, granulócitos e linfócitos dos animais tratados foram menores que os controles durante todo o experimento. A estimativa da celularidade da medula óssea näo mostrou diferenças significativas entre os 2 grupos. Apesar do peso do baço dos animais tratados com o benzeno näo diferir dos controles, existiam alteraçöes histológicas caracterizadas por diminuiçäo da celularidade da polpa vermelha e de megacariócitos

Oncogene expression in reticuloendotheliosis virus-transformed lymphoid cell lines and avian tissues.

The genome of reticuloendotheliosis virus (REV-T) contains a unique oncogene, designated v-rel, which is inserted into the env region. Employing a cloned rel DNA probe, a single 2.9- to 3.0-kilobase v-rel mRNA was identified in poly(A)+ RNA from REV-T-transformed lymphoid cell lines. A 4.0-kilobase rel-specific transcript corresponding to the cellular homolog of the v-rel oncogene was identified in MSB-1 cells, a herpesvirus-transformed lymphoid cell line. Cytodot hybridization was used to quantitate the levels of rel, c-rel, c-myc, c-myb, c-abl, c-fms, c-Ha-ras, c-Ki-ras, c-src, c-yes, c-mos, and c-sis mRNA in REV-T-transformed cells. The levels of rel transcription in REV-T-transformed cells were elevated only two to eightfold over levels found in the transformed immature avian lymphoid cell line MSB-1. The relatively modest levels of rel transcription in REV-T-transformed cells and the significant differences between the lengths of the v-rel and c-rel mRNA suggest that REV-T transformation is the result of the production of an altered rel protein. The c-rel proto-oncogene is expressed in all avian hematopoietic tissues but is not expressed at significant levels in brain and muscle. The transcription of other proto-oncogenes is not enhanced in REV-T-transformed lymphoid cell lines.

Quantitation of anthracyclines in human hematopoietic cell subpopulations by flow cytometry correlated with high pressure liquid chromatography.

The major white cell subpopulations present in bone marrow and peripheral blood can be discriminated by forward and perpendicular light scatter two-parameter flow cytometry (FCM). Fluorescent properties of anthracycline antibiotics allow measurement of the concentration of these cytotoxic drugs in hematopoietic cells by FCM as a third parameter. Analysis of scatter-gated fluorescence histograms provides quantitative information about the cellular concentration of at least four cell categories in human blood and bone marrow cells. A good correlation was found between the mean cellular fluorescence measured by FCM and the overall cellular concentration of adriamycin, daunomycin, and their main metabolites determined with high-pressure liquid chromatography (HPLC). In incubation experiments with human hematopoietic tissues, the final concentration of various anthracyclines in subpopulations of white cells appeared to be dependent on cell density, incubation time, temperature, and type of compound and its concentration. FCM analysis is a rapid, sensitive, and quantitative method for measurement of cellular anthracycline concentrations in subpopulations and therefore provides an useful new tool in monitoring chemotherapy.

Electrophoretic analysis of radiolabeled cell surface proteins and glycoproteins of some human hemopoietic cell lines.

Cell surface proteins and glycoproteins of several human lymphoblastoid- and neoplastic hemopoietic cell lines were radiolabeled by lactoperoxidase catalysed iodination and by sodium periodate/tritiated sodium borohydride. Electrophoretic patterns of radiolabeled proteins and glycoproteins obtained by electrophoresis under denaturing conditions (SDS-PAGE) were essentially similar for all examined lymphoblastoid cell lines, with a characteristic group of major radiolabeled glycoproteins gp44 and 24,31. Characteristic, individually different and distinguishable patterns of radiolabeled proteins were observed in different neoplastic hemopoietic cell lines: T-leukemia cell line MOLT 3, erythroleukemic cell line K562, pre-B cell leukemia line NALM 6, and a promyelocytic leukemia cell line HL-60. Cell surface proteins of HL-60 promyelocytic leukemia cell line displayed some similarities to those of another myeloid leukemia cell line ML 3. Examined Burkitt lymphoma cell lines were similar to lymphoblastoid cell lines with some minor differences. Glycoprotein gp44, markedly labeled on lymphoblastoid cell lines, was absent on Burkitt lymphoma cell line Daudi. Electrophoretic patterns of cell surface proteins of blast cells from a few patients with leukemia examined simultaneously with the cell lines are described and discussed.