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Biomedical subjects

M D Minden

Publications and source records attributed to M D Minden.

126 records · Page 7Linked to original sources
PubMed1986

The structure of the T cell antigen receptor genes in normal and malignant T cells.

In this review the genomic structure and the RNA transcripts of the alpha and beta chain of the T cell antigen receptor have been discussed. Studies of the structure of TcR beta in hematologic malignancies have revealed rearrangement in almost all of the T cell malignancies and a small proportion of non-T cell malignancies. In addition, clonal involvement of T cells in diseases such as Hodgkin's disease, angioimmunoblastic lymphadenopathy, and chronic T cell lymphocytosis have been observed. The study of the structure of the TcR beta gene is thus a useful tool for identifying clonal expansions of cells and in conjunction with studies of the immunoglobulin gene structure, and cell surface markers a useful tool for identifying cell lineage. At the present time the evaluation of the structure of the alpha chain genes has not been as fruitful. However, chromosome translocations involving the TcR alpha chain genes have been recognized and, in one case, this rearrangement has been in association with a known oncogene. With the isolation of more probes to the alpha chain region it should be possible to test its utility in identifying clonal populations and cell lineage. The recent isolation of the gamma gene of the T cell will also permit such studies. Preliminary results of studies carried out with a probe to the gamma chain gene of the T cell have paralleled results obtained with the TcR beta probe (unpublished observation).

Chromosomes, Human, 6-12 and X↗
PubMed1986

The structure of the T cell gamma chain gene in lymphoproliferative disorders and lymphoma cell lines.

During the development of B and T cells, a number of genes undergo rearrangement. In this paper we have studied the structure of the T cell gamma-chain gene in primary lymphomas and cell lines derived from patients with lymphoma. Samples derived from patients with angioimmunoblastic lymphadenopathy (AIL), Lennert's lymphoma, and Hodgkin's disease were also examined. TcR gamma was rearranged in all T cell lymphomas and in some B cell lymphomas and B cell lymphoma cell lines. Rearrangement of the gamma-chain gene was also found in AIL, Lennert's lymphoma, and four of eight cases of Hodgkin's disease. These studies indicate that rearrangement of TcR gamma is a useful clonal marker but does not aid in the identification of cell lineage.

Cell Line↗
PubMed1986

Effects of recombinant GM-CSF on the blast cells of acute myeloblastic leukemia.

The effects of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) were compared to those of media conditioned by the continuous bladder carcinoma line, HTB9 (HTB9-CM), using three criteria. First, both GM-CSF and HTB9-CM stimulated blast colony formation in methylcellulose cultures, patient-to-patient variations were seen in the dose-response curves, and GM-CSF was effective, but less so that HTB9-CM. Second, GM-CSF also enhanced growth of blast progenitors in suspension culture, indicating its capacity to support self-renewal. GM-CSF was as effective as HTB9-CM in the production of adherent cells during the growth of blast cells in suspension, a finding that is interpreted to mean that GM-CSF also supports postdeterministic events in blast differentiation. Finally, colonies growing in the presence of GM-CSF were not phenotypically different than those stimulated by HTB9-CM.

Cells, Cultured↗
PubMed1985

Somatic rearrangement of T-cell antigen receptor gene in human T-cell malignancies.

A cDNA clone representing the gene encoding the beta chain of the human T-cell antigen receptor has been isolated recently. By using fragments of this cDNA as hybridization probes in Southern blot analysis of restriction endonuclease-digested genomic DNA, we have now examined the structure of the gene in DNA from 26 patients with acute leukemia and from 23 normal individuals. We have found that the T-cell antigen receptor gene has undergone somatic rearrangement in 14 of 14 patients with the phenotypic diagnosis of T-cell acute lymphoblastic leukemia. In this group of patients, similar patterns of rearrangement appear to occur in different patients. This finding suggests that there is either a limited repertoire of possible rearrangements or an association between the development of leukemia and specific patterns of rearrangement. DNA from 6 patients with acute myeloblastic leukemia, 6 patients with non-B, non-T acute lymphoblastic leukemia, and 23 nonleukemic individuals showed no rearrangement or polymorphism. One case of T-cell acute lymphoblastic leukemia, however, showed rearrangement of both the T-cell receptor beta chain and the constant region of the immunoglobulin gene. Studies with mixtures of DNAs from leukemic bone marrow cells and cultured skin fibroblasts, as well as with remission and relapse marrow DNAs from the same patients, indicate that this technique can detect 1% leukemic cells in a mixed population. In addition, DNA from the marrow of a patient in relapse contains a similar rearrangement to that found in the marrow sample taken at the time of diagnosis, which suggests that the original clone of leukemic cells was responsible for relapse. Our results indicate that assessment of rearrangement of the T-cell antigen receptor gene will be valuable in the diagnosis and management of leukemia and can be used to evaluate clonality in T-cell neoplasia.

Chromosome Mapping↗
PubMed1985

Origin of leukemic relapse after bone marrow transplantation detected by restriction fragment length polymorphism.

Bone marrow transplantation has become an accepted modality in the treatment of acute leukemia. With this therapy, it is possible to obtain long-term disease-free survival. However, leukemia recurs occasionally. In most cases, leukemic relapse is of recipient origin. There have been several reports, though, of leukemia developing in donor cells. These cases have been limited to instances in which there is an easily identifiable chromosome difference or abnormality, usually a sex chromosome. In this paper we describe the use of restriction fragment-length polymorphism analysis to determine the origin of recurrent leukemia cells in which no identifying chromosome was present. We found that the leukemia had recurred in recipient cells. We also were able to demonstrate the presence of normal hemopoietic cells of donor origin.

Adult↗
PubMed1985

Varying degrees of amplification of the N-ras oncogene in the human breast cancer cell line MCF-7.

The oncogene N-ras has been found to be amplified (congruent to 20 copies) in the human breast carcinoma cell line MCF-7. The amplified sequences have been localized to a marker chromosome by in situ hybridization. Sublines of MCF-7, serially passaged in different laboratories, have marked variation in the degree of N-ras amplification. The differing degrees of amplification of N-ras are further evidence of heterogeneity within MCF-7 subclones. The phenomenon may not have general relevance for breast cancer, since other breast cancer cell lines and DNA from patient biopsies failed to show evidence of N-ras amplification.

Breast Neoplasms↗
PubMed1984

Chromosome-mediated transfer of the malignant phenotype by human acute myelogenous leukemic cells.

Acute myelogenous leukemia (AML) is a malignancy of the myeloid cells of the bone marrow. Recently, a number of groups have demonstrated that it is possible to study the malignant phenotype at the level of DNA through gene transfer experiments. We have used such an approach to determine whether it is possible to transfer the malignant phenotype of anchorage independence from human AML cells to anchorage-dependent rodent cells, using chromosomes as the source of genetic information. We found that chromosomes isolated from leukemic cell lines were capable of transferring the malignant phenotype of anchorage independence, whereas chromosomes derived from the lymphocytes of normal individuals were not active in this assay. Using Southern blot analysis of the DNA from transferants, we were able to show that the transfer of anchorage independence correlated with the presence of human DNA in the transferants. The pattern of human DNA in the transferants derived from different transfection experiments is compared.

Animals↗
PubMed1982

Detection of genes coding for human differentiation markers by their transient expression after DNA transfer.

We have developed an assay for specific genes in DNA based on transient expression. DNA prepared from patients with acute myeloblastic or acute lymphoblastic leukemia or from the continuous leukemic cell line HL60 was transferred to LTA cells; 48-72 hr later, these recipients expressed hemopoietic differentiation markers as detected by monoclonal antibodies against My-1 (granulocyte specific) and OK-T3 (T-cell specific) using immunofluorescence. The efficiency of transfer was dose and time dependent. We found that genes not expressed in the original cells were expressed after transfer by using this assay. Restriction enzyme analysis showed that My-1 was not expressed with DNA that had been incubated before transfer with either HindIII or Sal I but was present after digestion with either EcoRI or BamHI; after digestion of DNA with the same enzymes, OK-T3 expression was observed only in the HindIII-treated DNA. These studies indicate that DNA was transferred; this approach may provide an efficient method for detecting the activity of specific genes in the absence of selection.

Animals↗
PubMed1981

Lethality of human myeloblasts correlates with the incorporation of arabinofuranosylcytosine into DNA.

We recently demonstrated a highly significant relationship between the incorporation of 1-beta-D-arabinofuranosylcytosine (ara-C) into L1210 DNA and the loss of clonogenic survival. These studies have now been extended to the human promyeloblast (HL-60) cell line and myeloblasts from a patient with acute myelogenous leukemia. Our results demonstrate: (i) the specific internucleotide incorporation of ara-C into human myeloblast DNA; (ii) the lability of [3H]ara-C-labeled DNA to alkali which necessitates the use of nondegrading assay conditions; and (iii) a highly significant relationship (P less than 0.0001) between the loss of clonogenicity of these cells and the extent of ara-C incorporation. These findings suggest that the incorporation of ara-C into DNA is one of the initial events leading to cell lethality. This method is applicable to clinical samples of bone marrow and peripheral blood as an in vitro assay for studying the sensitivity of cell populations to this drug.

Cell Division↗
PubMed1980

Colony formation by normal and malignant human B-lymphocytes.

A method is described that permits colony formation in culture by B lymphocytes from normal blood and from blood, marrow or lymph nodes of patients with myeloma or lymphoma. The method depends on: (1) exhaustively depleting cell suspensions of T lymphocytes, (2) a medium conditioned by T lymphocytes in the presence of phytohaemagglutinin (PHA-TCM), and (3) irradiated autologous or homologous T lymphocytes. Under these conditions the assay is linear. Cellular development of B lymphocytes can be followed; differentiation to plasma cells is seen in cultures of cells from normal individuals and myeloma patients, but not lymphoma patients. Malignant B lymphocytes in culture produced immunoglobulin of the class identified in the patient's blood, or in freshly obtained cells. We conclude that the assay is suitable for studying the growth, differentiation and regulation of normal and malignant B lymphocytes in culture.

B-Lymphocytes↗
PubMed1979

Acute myeloblastic leukemia considered as a clonal hemopathy.

Acute myeloblastic leukemia, like certain other hematologic disorders, originates in pluripotent stem cells. Two general biologic processes underlie development of the disease. Over long times, clonal progression leads from normal polyclonal hemopoiesis through clonal preleukemia to leukemia. Overt leukemia is characterized by the emergence of blast cell populations. Over shorter times, clonal expansion yields cellular diversity based upon randomizing events. The analysis indicates that that blast population is of crucial importance. Characteristics of a colony assay for blast cell progenitors are presented.

Clone Cells↗
PubMed1979

Self-renewal in culture of proliferative blast progenitor cells in acute myeloblastic leukemia.

We have proposed that colonies of cells with blastlike morphology growing in culture are derived from a blast subpopulation with high proliferative potential. To test whether or not these blast progenitors have the capacity for self-renewal, blast colonies grown from the peripheral blood of the 21 patients with acute myeloblastic leukemia were replated; secondary colonies were observed in 17 instances, and these were similar to primary colonies in size, morphology, and culture requirements. Great patient-to-patient variation was observed in the frequency of secondary colonies, but low secondary plating efficiency was significantly correlated with successful remission induction. We conclude that the blast progenitors detected in the assay have at least limited self-renewal capacity and that this capacity may, along with other risk factors, contribute to clinical outcome.

Adult↗
PubMed1979

Separation of blast cell and T-lymphocyte progenitors in the blood of patients with acute myeloblastic leukemia.

The peripheral blood of acute myeloblastic leukemia (AML) patients often contains large numbers of two distinct cell populations, both capable of forming colonies in culture under similar conditions. The first population consists of the precursors of blast cells and has specificity for AML; the second population consists of T-lymphocyte precursors, also found in normal blood. The two progenitor populations can be separated by exploiting the capacity of T-lymphocyte (but not blasts) progenitors to form rosettes with sheep erythrocytes (E rosettes). After E-rosette formation, T-lymphocyte precursors can be removed by centrifugation on Ficoll-Hypaque. Such separation has a number of consequences: (1) Blast progenitors can be detected where unseparated mononuclear preparations have yielded either no colonies or only T-lymphocyte colonies (20 of 21 patients). (2) The stimulator requirements of the blast progenitors change, indicating that cell-cell interactions may take place between blast and T-lymphocyte progenitors. (3) It is feasible to characterize blast and T-lymphocyte precursors independently, even though they may coexist in peripheral blood. This may be important if progenitor properties are attributes contributing to the variance in outcome in AML.

Cell Division↗
PubMed1978

Proliferative state of blast cell progenitors in acute myeloblastic leukemia (AML).

Peripheral blood from patients with acute myeloblastic leukemia (AML) contains cells capable of giving rise to colonies in culture when stimulated by media conditioned by leukocytes (LCM) in the presence of phytohemagglutinin (PHA). Two types of colonies are recognized with high frequency: The first grows in the presence of low concentrations of PHA LCM, have a blast-like morphology, and are numerically correlated with morphologically identified blast cells. The second requires either high PHA LCM concentrations or PHA alone with or without 2-mercaptoethanol and consists of cells capable of forming rossettes with sheep erythrocytes and resembles. T-lymphocyte colonies from normal blood. Precursors of blast cell colonies from 15 leukemic patients were tested for cycle state, using either the 3H-thymidine or hydroxyurea techniques. All were found to have a high proportion of cells in the S phase of the cycle. In contrast, T lymphocyte precursors from three normal individual were quiescent. The data are consistent with the maintenance of the leukemic blast cell populations by the proliferative activity of a small subpopulation of blasts.

Adult↗
PubMed1978

Clonal expansion and progression in acute myeloblastic leukemia.

Diseaes originating in pluripotent stem cells, then developing through clonal expansion and clonal progression may properly be grouped together because of their common features. Among these, AML appears to be unique by reason of the presence within the clone of a blast cell population. Studies of cellular composition and regulation in AML clones require assays that measure not only myelopoiesis but also blast cell proliferation. The relation of the blast population to other components of AML clones remains uncertain. Resolution of the uncertainty is important in considering therapeutic strategies.

Bone Marrow Cells↗
PubMedDate not supplied

Organization and sequences of the variable, joining and constant region genes of the human T-cell receptor alpha-chain.

An essential property of the immune system is its ability to generate great diversity in antibody and T-cell immune responses. The genetic and molecular mechanisms responsible for the generation of antibody diversity have been investigated during the past several years. The gene for the variable (V) region, which determines antigen specificity, is assembled when one member of each of the dispersed clusters of V gene segments, diversity (D) elements (for heavy chains only) and joining (J) segments are fused by DNA rearrangement. The cloning of the beta-chain of the T-cell antigen receptor revealed that the organization of the beta-chain locus, which is similar to that of immunoglobulin genes, is also composed of noncontiguous segments of V, D, J and constant (C) region genes. The structure of the alpha-chain seems to consist of a V and a C domain connected by a J segment. We report here that the human T-cell receptor alpha-chain gene consists of a number of noncontiguous V and J gene segments and a C region gene. The V region gene segment is interrupted by a single intron, whereas the C region contains four exons. The J segments, situated 5' of the C region gene, are dispersed over a distance of at least 35 kilobases (kb). Signal sequences, which are presumably involved in DNA recombination, are found next to the V and J gene segments.

Amino Acid Sequence↗
PubMedDate not supplied

Breakpoints in the human T-cell antigen receptor alpha-chain locus in two T-cell leukaemia patients with chromosomal translocations.

Specific chromosomal translocations have been observed in several human and animal tumours and are believed to be important in tumorigenesis. In many of these translocations the breakpoints lie near cellular homologues of transforming genes, suggesting that tumour development is partly due to the activation of these genes. The best-characterized example of such a translocation occurs in mouse plasmacytoma and human B-cell lymphoma, where c-myc, the cellular homologue of the viral oncogene myc, is brought into close proximity with either the light- or heavy-chain genes of the immunoglobulin loci, resulting in a change in the regulation of the myc gene. T-cell malignancies also have characteristic chromosomal abnormalities, many of which seem to involve the 14q11-14q13 region. This region has recently been found to contain the alpha-chain genes of the human T-cell antigen receptor. Here we determine more precisely the chromosome breakpoints in two patients whose leukaemic T cells contain reciprocal translocations between 11p13 and 14q13. Segregation analysis of somatic cell hybrids demonstrates that in both patients the breakpoints occur between the variable (V) and constant (C) region genes of the T-cell receptor alpha-chain locus, resulting in the translocation of the C-region gene from chromosome 14 to chromosome 11. As the 11p13 locus has been implicated in the development of Wilms' tumour, it is possible that either the Wilms' tumour gene or a yet unidentified gene in this region is involved in tumorigenesis and is altered as a result of its translocation into the T-cell receptor alpha-chain locus.

Animals↗