20 results on '"Reuben, R. C."'
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2. Parasitological, serological, and molecular survey of trypanosomosis (Surra) in camels slaughtered in northwestern Nigeria
- Author
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Mamman, S. A., Dakul, D. A., Yohanna, J. A., Dogo, G. A., Reuben, R. C., Ogunleye, O. O., Tyem, D. A., Peter, J. G., and Kamani, J.
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- 2021
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3. Characterization and evaluation of lactic acid bacteria from indigenous raw milk for potential probiotic properties.
- Author
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Reuben, R. C., Roy, P. C., Sarkar, S. L., Rubayet Ul Alam, A. S. M., and Jahid, I. K.
- Abstract
Raw milk contains wide microbial diversity, composed mainly of lactic acid bacteria (LAB), which are used as probiotics in both human and animal husbandry. We isolated, characterized, and evaluated LAB from indigenous Bangladeshi raw milk to assess probiotic potential, including antagonistic activity (against Escherichia coli O157: H7, Enterococcus faecalis, Salmonella Typhimurium, Salmonella Enteritidis, and Listeria monocytogenes), survivability in simulated gastric juice, tolerance to phenol and bile salts, adhesion to ileum epithelial cells, auto- and co-aggregation, hydrophobicity, a-glucosidase inhibitory activity, and antibiotic susceptibility tests. The 4 most promising LAB strains showed probiotic potential and were identified as Lactobacillus casei, Lactobacillus plantarum (which produced plantaricin EF), Lactobacillus fermentum, and Lactobacillus paracasei. These strains inhibited all pathogens tested at various degrees, and competitively excluded pathogens with viable counts of 3.0 to 6.0 log cfu/mL. Bacteriocin, organic acids, and low-molecular-weight substances were mainly responsible for antimicrobial activity by the LAB strains. All 4 LAB strains were resistant to oxacillin and 3 were resistant to vancomycin and streptomycin, with multiple antibiotic resistance indices >0.2. After further in vivo evaluation, these LAB strains could be considered probiotic candidates with application in the food industry. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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4. Anti-Salmonella activity of metabolites from African soldier termites, Macrotermes bellicosus.
- Author
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Afolayan, E. M., Babayi, H., Reuben, R. C., and Akintola, R. I.
- Subjects
HEXANE ,TERMITES ,CARDIAC glycosides ,SALMONELLA typhi ,TYPHOID fever ,MILITARY personnel - Abstract
Copyright of African Journal of Clinical & Experimental Microbiology is the property of African Journals Online (AJOL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2019
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5. A new group of potent inducers of differentiation in murine erythroleukemia cells.
- Author
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Reuben, R C, Wife, R L, Breslow, R, Rifkind, R A, and Marks, P A
- Abstract
This report identifies a group of compounds, polymethylene bisacetamides (acetylated diamines), which are potent inducers of erythroid differentiation in murine erythroleukemia cells. A known inducing agent, N-methylacetamide, was dimerized through varying numbers of methylenes in an attempt to increase the local effective concentration at adjacent target sites. The simple dimer was no more effective than N-methylacetamide alone; introduction of five to eight methylenes between acetamide groups substantially increased the effectiveness of these compounds. The hexamethylene bisacetamide was active between 0.5 mM and 5 mM; the percentage of cells induced and the rate at which they were recruited to differentiation was dependent upon the concentration of inducer within this range. At 5 mM hexamethylene bisacetamide essentially the entire population (greater than 99%) was induced to a pathway of erythroid differentiation which was greater differentiation of the cultured cells than with any inducer yet tested.
- Published
- 1976
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6. Tumor promoter-mediated inhibition of cell differentiation: suppression of the expression of erythroid functions in murine erythroleukemia cells.
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Fibach, E, Gambari, R, Shaw, P A, Maniatis, G, Reuben, R C, Sassa, S, Rifkind, R A, and Marks, P A
- Abstract
Previous studies demonstrated that 12-O-tetradecanoyl-phorbol-13-acetate (TPA), a tumor promoter, is a potent inhibitor of inducer-mediated differentiation of murine erythroleukemia cells. Inhibition of cell differentiation was associated with inhibition of cell growth. The present studies, employing a cell line adapted for growth in TPA, demonstrate that inhibition of differentiation is not dependent upon inhibition of cell growth or a change in the cell division cycle; neither is inhibition of differentiation accompanied by detectable effect on cell uptake of [3H]hexamethylene bisacetamide, the inducer used in these studies. TPA causes an inhibition of expression of all hexamethylene bisacetamide-inducible erythroid characteristics measured, including commitment to terminal cell division, accumulation of globin mRNA, and synthesis of globins, spectrin, heme synthetic enzymes (delta-aminolevulinic acid dehydratase and uroporphyrinogen-I synthase) and heme. A hypothetical model for the inhibitory action of tumor promoters on terminal cell differentiation is discussed.
- Published
- 1979
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7. Transcriptional and post-transcriptional regulation of globin gene accumulation in murine erythroleukemia cells
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Profous-Juchelka, H R, Reuben, R C, Marks, P A, and Rifkind, R A
- Abstract
The mechanism responsible for the accumulation of newly synthesized alpha- and beta-globin mRNA in the cytoplasm of induced murine erythroleukemia cells was examined by nuclear mRNA nascent chain elongation (run-off transcription). Hexamethylenebisacetimide, a potent inducer of murine erythroleukemia cell differention, induced high levels of both alpha- and beta-globin gene transcription within 48 to 72 h in culture. Butyric acid, a modest inducer of murine erythroleukemia cells, induced a somewhat lower level of globin gene transcription. With both inducers, alpha-globin transcriptional rates exceeded those of beta-globin. Hemin, on the other hand, showed no detectable increase over the basal rate observed in uninduced cells, even at a time (48 h) when newly synthesized globin mRNA was accumulating in the cytoplasm. These results suggest that there are at least two mechanisms responsible for regulating alpha- and beta-globin structural gene expression in induced murine erythroleukemia cells and that the mechanisms involved are inducer dependent. Hexamethylenebisacetimide and butyric acid increase the rate at which globin genes are transcribed, but hemin appears to allow constitutive levels of transcripts to accumulate.
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- 1983
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8. Identification of the site of interruption in relaxed circles producing during bacteriophage lambda DNA circle replication
- Author
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Reuben, R C and Skalka, A
- Abstract
The DNA that accumulates in the lambda infection restricted to the early (circular) stage of replication consists of approximately two-thirds covalently closed circles and one-third relaxed circles bearing a single interruption in either strand of the duplex. The latter molecules are presumed to be a unique class in that the interruption is not repairable by DNA polymerase and ligase. Preferential radioisotopic labeling of the region immediately adjacent to the interruption, followed by hybridization to sheared fragments of the lambda chromosome with varying guanine plus cytosine content, suggested that the nick resides at the position of the mature molecular ends of the lambda chromosome. Digestion of the labeled molecules with restriction enzymes and reconstruction experiments in which Hershey circles were generated by annealing of interrupted strands isolated from the relaxed circles support this interpretation. The results indicate that the relaxed circles consist of a population containing one interruption in either of the two strands of the duplex jointly representing the two "nicks" contained in Hershey circles (in which the cohesive ends are annealed). These molecules could result from the inability of the maturation function to make the required staggered endonucleolytic cuts when the DNA substrate is a monomeric circle rather than a multimeric linear molecule. Alternatively, this interruption could be the result of an endonucleolytic cutting event critical to DNA replication.
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- 1977
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9. Multiple biological activities of human recombinant interleukin 1.
- Author
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Dinarello, C A, primary, Cannon, J G, additional, Mier, J W, additional, Bernheim, H A, additional, LoPreste, G, additional, Lynn, D L, additional, Love, R N, additional, Webb, A C, additional, Auron, P E, additional, and Reuben, R C, additional
- Published
- 1986
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10. Co-epidemics: have measures against COVID-19 helped to reduce Lassa fever cases in Nigeria?
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Reuben RC, Gyar SD, Makut MD, and Adoga MP
- Abstract
While the coronavirus disease 2019 (COVID-19) pandemic has multiple devastating public health and socio-economic effects across the world, Nigeria along with other West African countries is simultaneously faced with a recurrent Lassa fever epidemic. The complicating scenario is the similarity in the clinical manifestation of COVID-19 and Lassa fever, making the misdiagnosis of the initial presentation of both diseases a significant risk with an increased likelihood of co-infection. However, the strict implementation of COVID-19 infection prevention and control measures across Nigeria after the initial outbreaks concurrently resulted in the reduction of Lassa fever cases. The abrupt change in the behaviour of Lassa fever epidemiological data, which are attributable to the implementation of COVID-19 infection prevention and control measures at the national, sub-national and community levels, requires detailed investigation during and after the COVID-19 epidemic to elucidate the interactions and evolutionary dynamics of Lassa fever cases in Nigeria., (© 2021 The Authors.)
- Published
- 2021
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11. Regulation of globin gene expression during induced erythroid cell differentiation.
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Rifkind RA, Sheffery M, Profous-Juchelka HR, Reuben RC, and Marks PA
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- Animals, Cell Differentiation, Chromatin ultrastructure, Deoxyribonucleases, Leukemia, Erythroblastic, Acute genetics, Methylation, Mice, Erythropoiesis, Gene Expression Regulation, Globins genetics
- Abstract
We can provide increasing insight, albeit still incomplete, into the changes in MELC that accompany induced globin gene expression. It is suggested that these transformed CFU-E-like erythroid precursor cells exhibit in their uninduced state a DNA methylation pattern and globin gene chromatin configuration (DNase I sensitivity) that is compatible with actual or potential gene transcription. Such features may reflect alterations in chromatin configuration that occurred earlier, during the differentiation of erythroid precursor cells, which is associated with the restriction in developmental potential that is characteristic of progression to the CFU-E (or MELC) stage of erythropoiesis. Uninduced MELC display a low level of globin gene transcription, producing globin mRNA or mRNA precursors whose processing or stabilization is the site of action of hemin. The major increase in MELC globin gene transcription that is initiated by HMBA or butyric acid is accompanied by an increase in DNase I hypersensitivity in the regions 5' to the active globin genes. This suggests that reorganization of chromatin structure in the globin gene domains is associated with accelerated globin gene transcription and may be characteristic of a developmental stage transition during terminal differentiation in the erythroid cell lineage.
- Published
- 1983
12. Regulation of differentiation in normal and transformed erythroid cells.
- Author
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Rifkind RA, Marks PA, Bank A, Terada M, Reuben RC, Maniatis GM, Fibach E, Nudel U, Salmon JE, and Gazitt Y
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- Cell Cycle, Cell Line, Cell Transformation, Viral, Chromatin metabolism, DNA biosynthesis, Dimethyl Sulfoxide pharmacology, Erythropoietin pharmacology, Globins biosynthesis, Hemoglobins biosynthesis, RNA, Messenger biosynthesis, Cell Transformation, Neoplastic, Erythropoiesis
- Abstract
Studies are described employing two erythropoietic systems to elucidate regulatory mechanisms that control both normal erythropoiesis and erythroid differentiation of transformed hemopoietic precursors. Evidence is provided suggesting that normal erythroid cell precursors require erythropoietin as a growth factor that regulates the number of precursors capable of differentiating. Murine erythroleukemia cells proliferate without need of erythropoietin; they show a variable, generally low, rate of spontaneous differentiation and a brisk rate of erythropoiesis in response to a variety of chemical agents. Present studies suggest that these chemical inducers initiate a series of events including cell surface related changes, alterations in cell cycle kinetics, and modifications of chromatin and DNA structure which result in the irreversible commitment of these leukemia cells to erythroid differentiation and the synthesis of red-cell-specific products.
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- 1978
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13. Changes in cyclic adenosine 3':5'-monophosphate levels during induction of differentiation in murine erythroleukemia cells.
- Author
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Gazitt Y, Reuben RC, Deitch AD, Marks PA, and Rifkind RA
- Subjects
- 3',5'-Cyclic-AMP Phosphodiesterases antagonists & inhibitors, Acetamides pharmacology, Animals, Butyrates pharmacology, Cell Cycle drug effects, Cell Line, Diamines pharmacology, Dimethyl Sulfoxide pharmacology, Friend murine leukemia virus, Leukemia, Erythroblastic, Acute pathology, Tumor Virus Infections metabolism, Cyclic AMP metabolism, Erythropoiesis drug effects, Leukemia, Erythroblastic, Acute metabolism, Leukemia, Experimental metabolism
- Published
- 1978
14. Effect of hexamethylene bisacetamide on the commitment to differentiation of murine erythroleukemia cells.
- Author
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Fibach E, Reuben RC, Rifkind RA, and Marks PA
- Subjects
- Animals, Cell Division drug effects, Clone Cells pathology, DNA, Neoplasm biosynthesis, Dimethyl Sulfoxide pharmacology, Dose-Response Relationship, Drug, Erythropoiesis drug effects, Hemoglobins biosynthesis, Kinetics, Leukemia, Erythroblastic, Acute metabolism, Leukemia, Experimental metabolism, Leukemia, Experimental pathology, Acetamides pharmacology, Cell Differentiation drug effects, Leukemia, Erythroblastic, Acute pathology
- Abstract
Friend virus-transformed murine erythroleukemia cells express the program of erythropoietic differentiation under the influence of the previously described, potent inducing agent, hexamethylene bisacetamide. Commitment to differentiation, defined as the ability to continue the processes of differentiation in the absence of inducer, has been examined at the single-cell level, with a combination of suspension and cell-cloning techniques. Recruitment of committed cells is shown to occur prior to the detectable accumulation of hemoglobin or the appearance of morphological changes characteristic or erythroid maturation. The stability of the commitment of murine erythroleukemia cells to differentiate is found to be dependent upon both the concentration of hexamethylene bisacetamide and the duration of exposure to the inducing agent. Under conditions less than optimal for induction, a single cell can give rise to a colony containing both differentiated and undifferentiated cells. On the basis of these findings, it is suggested that fully stabilized differentiation, in addition to the previously demonstrated requirement for the inducing agent to be present during a cell-cycle S phase, involves subsequent stabilizing event(s) caused by a direct or indirect action of the inducing agent.
- Published
- 1977
15. Studies on the mechanism of action of hexamethylene bisacetamide, a potent inducer of erythroleukemic differentiation.
- Author
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Reuben RC
- Subjects
- Animals, Cell Differentiation, Cell Line, Diamines metabolism, Mice, Subcellular Fractions metabolism, Acetamides pharmacology, Erythrocytes cytology, Leukemia, Erythroblastic, Acute physiopathology
- Abstract
Hexamethylene bisacetamide (diacetyldiamino hexane) is a potent inducer of erythroid differentiation in murine erythroleukemia cells. Hexamethylene bisacetamide and the closely related pentamethylene bisacetamide were synthesized with radioactive labels in various portions of the molecule and the uptake, metabolism, and intracellular distribution determined. Bisacetamides are taken up by the cell; an intracellular concentration equal to the extracellular concentration is achieved by 6-8 h. Commitment to differentiation is not detected until at least 10 h after equilibration. Both uptake and commitment to differentiate are concentration and temperature dependent. The majority of the compound is deacetylated upon cell entry and the acetate portion incorporated nonspecifically into lipid and protein. Acetate competes with the incorporation of hexamethylene bisacetamide into protein and lipid, but does not affect inducing activity. The diamine portion of the molecule is detected only in the cytoplasm, in a trichloroacetic acid-soluble and acetylated form, whereas the acetate moiety is detected in both cytoplasm and nucleus and in both a trichloroacetic acid-soluble and insoluble form. The cellular uptake of diamines and bisacetamides (acetylated diamines) are similar, but acetylation of the diamine greatly increases inducing activity.
- Published
- 1979
- Full Text
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16. Induction of globin gene expression during erythroid cell differentiation.
- Author
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Rifkind RA, Sheffery M, Profous-Juchelka HR, Reuben RC, and Marks PA
- Subjects
- Animals, Cell Differentiation drug effects, Chromatin ultrastructure, DNA (Cytosine-5-)-Methyltransferases metabolism, Deoxyribonuclease I, Endodeoxyribonucleases metabolism, Mice, Transcription, Genetic, Gene Expression Regulation, Globins genetics, Leukemia, Erythroblastic, Acute genetics
- Abstract
We can provide increasing insight, albeit still incomplete, into the changes in MELC that accompany globin gene expression induced by polar chemicals, such as DMSO, and other agents. These transformed, CFUe-like erythroid precursor cells exhibit in their uninduced state, a DNA methylation pattern and globin gene (formula; see text) chromatin configuration (DNase I sensitivity) that is compatible with actual or potential gene transcription. Such features may reflect alterations in chromatin configuration that have occurred at a stage prior to leukemic transformation, during the differentiation of earlier erythroid precursor cells and associated with the restriction in developmental potential characteristic of progression to the CFUe (or MELC) stage of erythropoiesis. Uninduced MELC display a low level of globin gene transcription, producing globin mRNA or mRNA precursors whose processing or stabilization is the target of action of hemin. The major increase in MELC globin gene transcription that is initiated by DMSO, HMBA, or butyric acid, is accompanied by, and perhaps preceded by, an increase in DNase I hypersensitivity in the regions 5' to the active globin genes. This suggests that reorganization of chromatin structure in the globin gene domains is associated with accelerated globin gene transcription and may be characteristic of a developmental transition during terminal differentiation in the erythroid cell lineage.
- Published
- 1983
- Full Text
- View/download PDF
17. Inducers of erythroleukemic differentiation. Relationship of structure to activity among planar-polar compounds.
- Author
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Reuben RC, Khanna PL, Gazitt Y, Breslow R, Rifkind RA, and Marks PA
- Subjects
- Acetamides pharmacology, Amides pharmacology, Carboxylic Acids pharmacology, Cell Line, Dicarboxylic Acids pharmacology, Dimethyl Sulfoxide pharmacology, Structure-Activity Relationship, Cell Differentiation drug effects, Leukemia, Erythroblastic, Acute physiopathology
- Abstract
Hexamethylenebisacetamide is a potent inducer of erythroid differentiation in murine erythroleukemia cells. A series of chemical compounds structurally related to hexamethylenebisacetamide were tested for inducing activity including polymethylene chains terminally substituted with various combinations of carboxylate, amino, amide, or sulfoxide groups. Effective "dimerization" of dimethyl sulfoxide through a linear polymethylene chain increases its inducing activity by a magnitude similar to that observed when N-methylacetamide is effectively dimerized in such a manner. It was found that all potent inducing agents possess both a hydrophilic and hydrophobic portion of the molecule, as well as a planar portion. All are Lewis bases, possessing a free electron pair available for hydrogen bonding. The polymethylene chain joining functional groups must be flexible and must be 5 to 6 carbon atoms in length to achieve maximal activity. Introduction of triple or double (cis or trans) bonds into the polymethylene chain does not alter activity.
- Published
- 1978
18. Analysis of globin genes from murine erythroleukemia cells.
- Author
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Reuben RC, Lenny AB, and Stotish RL
- Subjects
- Animals, Cell Line, Cloning, Molecular, DNA Restriction Enzymes, Friend murine leukemia virus genetics, Genes, Mice, Multiple Myeloma genetics, Neoplasms, Experimental genetics, Polymorphism, Genetic, Tumor Virus Infections genetics, Globins genetics, Leukemia, Erythroblastic, Acute genetics
- Abstract
Globin structural genes from a murine erythroleukemia cell line were analyzed by Southern blot hybridization of genomic DNA and after isolation of cloned globin genes from a genomic library. The globin genes isolated from the erythroid cell line did not differ, when analyzed by extensive restriction endonuclease digestion, from globin genes isolated from nonerythroid cells. No gross structural differences were seen between murine erythroleukemia globin genes, either before or after hexamethylene bisacetamide (HMBA)-mediated erythroid differentiation, and globin genes from normal mouse liver DNA. Whereas the murine erythroleukemia genome hybridizes extensively to cloned Friend leukemia virus probes, there was no evidence of viral integration into sequences adjacent to the globin genes.
- Published
- 1983
19. Chemically induced murine erythroleukemic differentiation.
- Author
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Reuben RC, Rifkind RA, and Marks PA
- Subjects
- Acetamides pharmacology, Animals, Anti-Bacterial Agents pharmacology, Antineoplastic Agents pharmacology, Cell Cycle, Cell Line, DNA-Directed DNA Polymerase metabolism, Globins biosynthesis, Kinetics, Mice, Protein Biosynthesis, RNA, Messenger biosynthesis, Spectrin biosynthesis, Transcription, Genetic, Cell Differentiation drug effects, Leukemia, Experimental physiopathology
- Published
- 1980
- Full Text
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20. DNA polymerase activities during induced differentiation in murine erythroleukemia cells.
- Author
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Giri JG, Reuben RC, Rifkind RA, and Marks PA
- Subjects
- Acetamides pharmacology, Animals, Cell Cycle, Cell Division, Cell Separation, Cells, Cultured, Diamines pharmacology, Mice, Nucleic Acid Synthesis Inhibitors, Cell Differentiation, DNA-Directed DNA Polymerase metabolism, Leukemia, Erythroblastic, Acute enzymology, Leukemia, Experimental enzymology
- Published
- 1981
- Full Text
- View/download PDF
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