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Biomedical subjects

M L Cleary

Publications and source records attributed to M L Cleary.

At least 145 records · Page 8Linked to original sources
PubMed1985

Nucleotide sequence of a t(14;18) chromosomal breakpoint in follicular lymphoma and demonstration of a breakpoint-cluster region near a transcriptionally active locus on chromosome 18.

The t(14;18)(q32;21) chromosomal translocation characteristic of follicular lymphomas is the most common cytogenetic abnormality known to be associated with any specific type of hematolymphoid malignancy. A fragment of DNA containing the crossover point between chromosomes 14 and 18 was cloned from the tumor cells of a patient with a follicular lymphoma carrying this translocation. Nucleotide sequence analysis of the breakpoint DNA revealed that the break in chromosome 14 occurred in joining region 4(J4) of the nonfunctional immunoglobulin heavy chain allele. This finding and other structural similarities of the breakpoint with the functional diversity region-joining region (D-J) joint in this lymphoma suggest that D-J recombination enzymes played a role in the mechanism of the t(14;18) translocation. Hybridization analysis of DNA from 40 follicular lymphomas showed that the majority of t(14;18) translocations occur on chromosome 18 DNA within 4.2 kilobases of the cloned breakpoint. A DNA probe from this breakpoint-cluster region detects transcription products in the tumor cells from which it was cloned and in a B-lymphoma cell line containing a t(14;18) translocation.

Alleles↗
PubMed1985

Leukemia with Down's syndrome: translocation between chromosomes 1 and 19 in acute myelomonocytic leukemia following transient congenital myeloproliferative syndrome.

A girl with Down's syndrome was born with a myeloproliferative disorder. The child had spontaneous regression of the myeloproliferation, with acute leukemia developing at a later date. Morphologic, cytochemical, immunologic, and immunoglobulin gene configuration studies all supported the diagnosis of acute nonlymphocytic leukemia. High-resolution chromosome studies revealed that the leukemic cells consistently contained a translocation between chromosomes 1 and 19: der(19)t(1;19)(q25;p13). Spontaneous regression of the transient myeloproliferative syndrome of the newborn with Down's syndrome may not always be permanent, and the transient myeloproliferative syndrome may sometimes represent an early sign of acute nonlymphocytic leukemia.

Antibodies, Monoclonal↗
PubMed1985

Acute leukemias associated with the 4;11 chromosome translocation have rearranged immunoglobulin heavy chain genes.

Studies of acute leukemia with the 4;11 translocation have yielded conflicting results regarding the lineage of the cell of origin in this disease. To investigate this issue further, we have examined the state of immunoglobulin genes in tumor cells from two affected patients, immunophenotyped their leukemic cells using a number of monoclonal antibody reagents with specificities for lymphoid or myelomonocytic antigens, and examined the malignant cells by electron microscopy. DNA was extracted from leukemic bone marrow cells and hybridized with radiolabeled DNA fragment probes specific for the constant region of immunoglobulin heavy chain and kappa and lambda light chain genes. Autoradiographs revealed rearrangement of both allelic heavy chain genes, but a germline configuration of light chain genes in both cases. Surface marker analysis showed that blasts from both patients expressed HLA-DR and the myeloid antigens Leu-M1, 1C2, 2D1, and 4B3, but lacked common acute lymphocytic leukemia antigen or T antigens. Furthermore, they did not have sheep erythrocyte receptors nor did they express surface or cytoplasmic immunoglobulin or B cell precursor determinants. Electron microscopy analysis showed that blast cells from patient 1 exhibited numerous monoribosomes, polyribosomes, and isolated strands of rough endoplasmic reticulum in their cytoplasm. These ultrastructural features are characteristic for both common acute lymphocytic leukemia and pre-B-ALL cells, but not for T-ALL or acute myelogenous leukemia cells. Peroxidase was undetectable in cells from both patients. Our study suggests that this disorder represents a unique subtype of leukemia. The cell of origin may be an early B cell progenitor that shares certain surface antigens with myeloid cells or a stem cell with the potential for both lymphoid and myelomonocytic differentiation.

Antigens, Neoplasm↗
PubMed1985

DNA rearrangements in non-Hodgkin's lymphomas.

The configuration of DNA at genetic loci that undergo somatic recombination in lymphocytes provides genetic markers that are useful in the diagnosis and characterization of non-Hodgkin's lymphomas. The loci containing rearranged DNA fall into three groups: the immunoglobulin genes, the T cell receptor genes and sites of chromosomal rearrangements, such as chromosomal translocations. DNA fragments cloned from these loci can be used as hybridization probes to characterize the rearranged DNA sequences in biopsy tissues. Only probes for chromosomal rearrangements are capable of directly diagnosing neoplasia and histological subtypes; however, probes for rearrangements of immunoglobulin and T cell receptor genes are valuable for detecting clonal proliferations, determining B or T cell derivation of tumours and distinguishing individual clones of lymphocytes from each other. Applications of DNA rearrangements have already yielded a number of important findings concerning the biology of human lymphoma. These discoveries have included the existence of multiclonal B cell cancers, the widespread dissemination of occult tumour to lymph nodes in mycosis fungoides, the high incidence of circulating tumour cells in patients with low grade lymphomas and the molecular heterogeneity of chromosomal break-points in follicular lymphomas.

B-Lymphocytes↗
PubMed1985

Frequent immunoglobulin and T-cell receptor gene rearrangements in "histiocytic" neoplasms.

The authors have analyzed the DNA of immunoglobulin and T-cell receptor genes in a series of 6 malignancies which were judged to be of histiocytic derivation on the basis of morphologic criteria. They found that 4 of these cases showed rearrangements of the beta T-cell receptor genes in spite of the lack of any specific immunohistochemical markers for B or T cells. One case showed rearrangements of both heavy and light chain immunoglobulin genes and probably represents either a sinusoidal large cell lymphoma or a B-cell lymphoma with activation of histiocytes simulating malignant histiocytosis. A single case lacked both immunoglobulin and T-cell receptor rearrangements consistent with immunologic analyses that suggested its origin from an interdigitating reticulum cell. The result of this study in conjunction with the authors' previous immunologic observations suggests that many presumed histiocytic malignancies actually represent T-cell lymphomas. Alternatively, beta T-cell receptor rearrangement may be a common feature of tumors that show monocyte/histiocytic differentiation.

Antibodies, Monoclonal↗
PubMed1985

Detection of two distinct malignant B cell clones in a single patient using anti-idiotype monoclonal antibodies and immunoglobulin gene rearrangement.

Immunoglobulin gene rearrangement analysis and somatic cell hybridization techniques were used to examine the malignant cell population in an unusual patient with hairy cell leukemia and macroglobulinemia (N Engl J Med 296:92, 1977). Although previous investigations suggested that the IgM macroglobulin was secreted by the circulating leukemia cells, anti-idiotype monoclonal antibodies raised to the IgM macroglobulin failed to react with the malignant cells in the circulation and bone marrow. In contrast, approximately 50% of the mononuclear cells from an enlarged inguinal lymph node reacted strongly with the anti-idiotype antibodies. Subsequent reanalysis of all cell populations demonstrated that whereas the circulating and bone marrow cells were IgM kappa-bearing, the macroglobulin was IgM gamma-bearing and the lymph node cells were evenly divided among IgM kappa-bearing and IgM gamma-bearing. Immunofluorescence flow cytometry indicated that those lymph node cells that reacted strictly with the anti-idiotype antibody were IgM gamma-bearing, demonstrating that they were the source of macroglobulin. An analysis of immunoglobulin gene DNA confirmed the coexistence of two distinct malignant B cell populations in the lymph node and indicated that the IgM kappa-bearing lymph node cells were identical to the circulating and bone marrow leukemic cells.

Aged↗
PubMed1985

Most null large cell lymphomas are B lineage neoplasms.

DNA of immunoglobulin and the beta T cell receptor genes was analyzed for rearrangements in 34 diffuse large cell lymphomas that failed to express immunoglobulins or T cell antigens. Twenty-eight cases had both heavy and light chain immunoglobulin rearrangements, two cases had only heavy chain gene rearrangements, three cases had only light chain gene rearrangements, and one case failed to show rearrangements for any of the immunoglobulin genes. None of the cases showed rearrangements for the beta T cell receptor gene. These results indicate that the vast majority of diffuse large cell lymphomas that lack definitive B or T cell phenotypic markers are actually B cell in origin.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1984

Lymphoproliferative disorders in cardiac transplant recipients are multiclonal lymphomas.

Tissue specimens from 5 immunosuppressed cardiac transplant recipients with lymphoproliferative disorders were examined for rearrangements in immunoglobulin DNA. In each case DNA analysis of tissues obtained from several sites or at various times showed different clonal immunoglobulin gene rearrangements for each of the three immunoglobulin gene loci. These findings indicate that lymphoproliferative disorders in immunosuppressed cardiac transplant recipients represent multiclonal or oligoclonal B cell lymphomas.

Biopsy↗
PubMed1984

Biclonal B-cell lymphoma.

The cells of most tumors are considered to be genetically homogeneous because they are assumed to represent a single clone descended from one abnormal cell. We have discovered three cases of B-cell lymphoma for which this generalization is not true. In each case, the tumor was composed of two subpopulations of cells, each expressing a different immunoglobulin molecule. Antibodies directed against these immunoglobulins were used to separate the two cell subpopulations of each tumor on a fluorescence-activated cell sorter. DNA extracted from the original tumor and the two fractionated subpopulations was analyzed to determine the configuration of immunoglobulin genes. Differences were found in the arrangement of DNA in at least one immunoglobulin gene for each of the two subpopulations. Thus, biclonality of these tumors was revealed by examination of both protein markers (cell-surface immunoglobulin) and DNA markers (immunoglobulin-gene rearrangements). Our results indicate that the incidence of biclonal B-cell lymphoma may be higher than previously recognized, possibly as high as 10 per cent of all B-cell lymphomas. Furthermore, our findings may have important implications for the diagnosis and therapy of lymphoid cancers.

Adult↗
PubMed1984

Monoclonality of lymphoproliferative lesions in cardiac-transplant recipients. Clonal analysis based on immunoglobulin-gene rearrangements.

Whether lymphoproliferative disorders arising in immunosuppressed recipients of organ transplants are primarily neoplastic or hyperplastic in nature is a matter of controversy. Reports of polyclonal B-cell proliferations in these lesions suggest the presence of hyperplasia, but these disorders resemble lymphoma histologically and are clinically aggressive and often rapidly fatal, as expected of a malignant neoplastic disease. We examined tissue specimens from 10 cases of lymphoproliferative disease that occurred in immunosuppressed recipients of cardiac transplants. Specimens from nine of these patients lacked cellular immunoglobulin; however, analysis of DNA extracted from these tissues revealed that each lesion contained large numbers of cells possessing uniform, clonal rearrangements of immunoglobulin-gene DNA. Therefore, when first seen clinically these proliferations contained a notable monoclonal-cell population typical of conventional B-cell lymphomas that are not associated with immunosuppression. We therefore suggest that lymphoproliferative disorders in recipients of cardiac transplants are neoplastic at the earliest stages of detectable disease.

Adolescent↗
PubMed1984

Immunoglobulin gene rearrangement as a diagnostic criterion of B-cell lymphoma.

We describe the use of the Southern blot hybridization technique to diagnose B-cell lymphoma by detecting clonal immunoglobulin gene rearrangements in lymph node and other biopsy tissues. DNA was isolated from a wide variety of neoplastic and non-neoplastic specimens and analyzed for the presence of rearranged immunoglobulin genes using radiolabeled DNA probes specific for the heavy- and light-chain immunoglobulin constant region genes. Among the specimens examined, clonal immunoglobulin gene rearrangements were found only in biopsy samples of B-cell lymphoma and not in samples containing reactive lymphoid processes or non-B-cell cancers. In lymphomas, the presence of rearrangements for either the kappa or lambda light-chain gene correlated with expression of one or the other of these chains when cellular immunoglobulins could be detected by frozen-section immunophenotyping techniques. The analysis of immunoglobulin gene rearrangements offers several advantages over conventional diagnostic methods for lymphomas, including improved sensitivity in detecting minor populations of neoplastic lymphocytes composing as little as 1% of the total cell population. In addition, clonal immunoglobulin gene rearrangements are demonstrable in a subset of lymphomas that lack detectable surface or cytoplasmic immunoglobulin, thus offering positive evidence for both malignancy and the B-cell origin of these tumors. Our studies indicate that detection of immunoglobulin gene rearrangements is a valuable method for diagnosis and classification of various lymphoproliferative disorders that are difficult to evaluate histologically or that lack distinctive antigenic markers.

B-Lymphocytes↗
PubMed1984

Immunoglobulin gene rearrangements in hairy cell leukemia.

Studies of hairy cell leukemia have yielded conflicting data about the cell of origin in this disease. To investigate this issue, we have examined the state of immunoglobulin genes in the cells of 11 randomly selected spleens showing histologic involvement with hairy cell leukemia. DNA was extracted from splenic tissue samples and digested with restriction endonucleases. Following agarose gel electrophoresis and transfer to nitrocellulose filters or activated nylon membranes, splenic DNA was hybridized with radiolabeled DNA fragment probes specific for the constant regions of the immunoglobulin heavy chain and kappa and lambda light chain genes. Autoradiograms of the hybridized DNA in each case revealed rearrangements of a heavy chain gene and at least one light chain gene. In addition, immunophenotyping of cellular immunoglobulin polypeptides was carried out on frozen tissue sections from all but one case. In each case in which an immunoglobulin polypeptide could be detected, a rearrangement was present in the DNA of the corresponding immunoglobulin gene. These studies offer strong evidence for endogenous immunoglobulin synthesis in hairy cells and for the B lymphocytic character of this leukemia.

B-Lymphocytes↗
PubMed1981

Transcription of the beta-like globin genes and pseudogenes of the goat in a cell-free system.

We have examined the transcription in a cell-free system of all the members of a highly regulated gene family, the beta-like hemoglobin genes of the goat. These five genes, which code for embryonic, fetal, juvenile, and adult beta-globin proteins, are all transcribed to roughly the same extent in the in vitro system. In all cases initiation of transcription is accurate. However, two goat beta-globin pseudogenes, as well as several artificially constructed deletion mutants, are not transcribed in vitro. A common feature of the transcriptionally inactive genes is the lack of an AT-rich consensus sequence just upstream of the presumptive initiation site.

Animals↗
PubMed1981

Two related pseudogenes are the result of a gene duplication in the goat beta-globin locus.

We report the nucleotide sequence of two goat beta-globin pseudogenes, psi beta X and psi beta Z, each of which is linked upstream from a functional goat beta-globin gene. Comparison to the functional beta A gene indicates that these two pseudogenes share several identical mutations. These include alterations of the ATA box, an early frameshift mutation in exon 1 and alterations of the universal GT/AG excision sequence of IVS1. The shared deleterious mutations indicate that the two pseudogenes diverged from a common defective sequence. Comparison of the pseudogenes with the functional beta A and beta C genes reveal that the psi beta X-beta C pair and psi beta Z-beta A pair may have been created by a single en bloc duplication event. The persistence and duplication of defective sequences may indicate a role for these pseudogenes as a spacer or regulator.

Animals↗
PubMed1981

Structure and evolution of goat gamma-, beta C- and beta A-globin genes: three developmentally regulated genes contain inserted elements.

We have determined the complete nucleotide sequence of the goat fetal (gamma), preadult (beta C) and adult (beta A) globin genes. In contrast to other globin genes expressed in different stages of development, these three genes are highly homologous (approximately 90%) in both their coding and noncoding regions. The only major difference between them results from elements inserted into their large introns: gamma contains a 247 bp insertion, beta A contains a 318 bp insertion, and beta C contains both a 252 bp insertion and a 60 bp deletion. Based on comparisons of these three genes to each other and to two goat globin pseudogenes, psi beta X and psi beta Z, we conclude that gamma, beta A and beta C have diverged relatively recently, and that the two gene pairs psi beta X - beta C and psi beta Z-beta A arose via a block duplication of an ancestral pseudogene-functional gene pair. Moreover, as opposed to the human fetal genes (G gamma and A gamma), the goat gamma gene appears to be a true beta-like gene that has fetal-specific function. The insertions in gamma, beta A and beta C contain sequence features characteristic of transposon-like elements, and appear to be represented in multiple copies throughout the genome.

Animals↗
PubMed1980

Identification by nucleotide sequence analysis of a goat pseudoglobin gene.

We have recently prepared a recombinant library of goat genomic DNA and have isolated clones containing th known goat globin genes. These include the alpha, gamma, beta C and beta A genes. In addition to these, another beta-like sequence has been observed. In this communication we report the complete nucleotide sequence of this gene, excluding a portion of the large intervening sequence. Several features suggest that this is a non-functional or pseudoglobin gene. The alterations include a frameshift mutation, substitution of the heme-binding histidines, a mutated termination codon, a change in the GT/AG excision sequence of the 5' end of the first intervening sequence, an AT rich sequence in the 3' untranslated region, and a mutated Hogness-Goldberg box. We conclude that this gene cannot function in the synthesis of globin.

Animals↗
PubMed1978

Production of "rapid-harvest" Moloney murine leukemia virus by continuous cell culture on synthetic capillaries.

Moloney murine leukemia virus was harvested automatically within 60 min of release from chronically infected NIH/3T3 cells (clone 1) cultured on bundles of synthetic capillaries. Production of virus as measured by a determination of reverse transcriptase activity and by the XC syncytia assay demonstrated that highly infectious "rapid-harvest" virus was recovered from NIH/3T3 cells (clone 1) grown for periods of up to 10 days.

Cell Line↗