Biomedical subjects
B R Reeves
Publications and source records attributed to B R Reeves.
Structural alterations of the RB1 gene in human soft tissue tumours.
Sixty-nine primary soft tissue tumours were examined for alterations of the RB1 gene which has previously been implicated in the genesis of retinoblastoma. In three tumours loss of both alleles of this gene (homozygous deletion) was detected. Two of these, both leiomyosarcomas, contained a chromosomal breakpoint within the RB1 gene, while in the third tumour, a radiation induced sarcoma, complete deletion was observed. Using a probe that detects a polymorphic locus within the RB1 gene we found loss of only one allele (heterozygous deletion) in 33% of soft tissue sarcomas examined, including two leiomyosarcomas, a malignant peripheral nerve sheath tumour, a rhabdomyosarcoma and a chondrosarcoma. When taken together our results suggest that alterations of the RB1 locus may play an important part in the pathogenesis of soft tissue tumours and particularly in leiomyosarcomas which accounted for four of the eight RB1 alterations observed in this study.
Characterization of the human cell line TE671.
The cell line TE671 has been widely used as a model of human medulloblastoma. In the present study we have demonstrated that transfection of DNA from this cell line into NIH 3T3 cells reveals the presence of an activated N-ras gene. Using oligonucleotide probes we have shown that the N-ras gene is activated by a point mutation at the third base of codon 61 resulting in the substitution of histidine for glutamine in the p21 ras gene product. We noted that this relatively uncommon activating mutation is also present in the human rhabdomyosarcoma cell line RD. Based on this finding and on the observation that several of the phenotypic characteristics of TE671, such as the presence of muscle-type nicotinic acetylcholine receptors and the intermediate filament protein desmin, are suggestive of myoid origin we investigated the possible identity of these two cell lines. Cytogenetic analysis revealed the presence of marker chromosomes common to both TE671 and RD. DNA fingerprinting using both locus specific and multilocus core probes showed indistinguishable band patterns in the two cell lines. Taken together our data show that TE671 and RD are derivatives of the same cell line and we conclude that the properties of the TE671 line should be ascribed to rhabdomyosarcoma rather than medulloblastoma cells.
Simultaneous application of immunolabelling and in situ hybridization to detect the origin of B and T lymphocytes in a case of acute lymphocytic leukaemia after bone marrow transplantation.
Previous cytogenetic studies, using selective mitogens, on a patient with B cell acute lymphocytic leukaemia during the 6 years of remission after bone marrow transplantation from an HLA-identical sister indicated persistence of recipient B lymphocytes in the peripheral blood. Such studies are necessarily limited to dividing cells at metaphase, which represent only a small proportion of the total cell population. We have now combined the techniques of immunolabelling and in situ hybridization on the patient's peripheral blood lymphocytes in order to define accurately their individual lineage and gender. A clear difference in the proportion of the persisting recipient lymphocytes was found between B and T lymphocyte lineages.
Characterization of the translocation between chromosomes X and 18 in human synovial sarcomas.
Recent studies have identified a specific chromosomal translocation, t(X;18)(p11.2;q11.2), in a high proportion of human synovial sarcomas. As a first step towards characterizing the X;18 translocation we have established a synovial sarcoma cell line. Fusion of this cell line to mouse RAG cells gave rise to somatic cell hybrids that contain the derivative (X) marker chromosome in the absence of other genetic material from chromosomes 18 and X. Southern analysis of DNA from these somatic cell hybrids demonstrated that the human X chromosome markers DXS94, DXS14, DXZ1 and DXS62 were retained. In contrast DXS7, GAPDP1, ARAF1, DXS146 were not consistently present in the hybrids indicating that these markers were on the region of the X chromosome replaced by part of the long arm of chromosome 18 during the generation of the X;18 translocation. The predicted position of the translocation relative to X chromosome markers is DXS7-DXS146-X; 18-DXS14-DXZ1-DXS94.
A consistent chromosome translocation in synovial sarcoma.
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Translocation t(12;16) in a case of myxoid liposarcoma.
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Ultrastructural, immunocytochemical, and cytogenetic characterization of a human epithelioid sarcoma cell line (RM-HS1).
A cell line (RM-HS1) derived from a human epithelioid sarcoma was established in tissue culture. Ultrastructurally, the cells show features of those found within the primary tumor. A mixed mesenchymal-epithelial phenotype, defined by reactivity with antibodies to epithelial membrane antigen and to vimentin and keratin intermediate filaments, was found in the tumor, and a similar phenotype persisted in the cultured cells. Cytogenetic analysis revealed a mode of 66 chromosomes. With the use of a variety of banding techniques together with in situ hybridization of a 3H-labeled molecular probe for 18s and 28s ribosomal RNA genes (pX1r101), the karyotypes were shown to contain extensive numerical and structural rearrangements, with up to 24 marker chromosomes.
Chromosomal localization of human endogenous retroviral element ERV1 to 18q22----q23 by in situ hybridization.
From a clone containing the entire locus of human endogenous retroviral element ERV1, we have obtained a DNA probe that is specific for the 3' long terminal repeat (LTR) sequence. This probe was used to map the LTR of ERV1 by in situ hybridization to chromosomes from normal human blood lymphocytes. The LTR was found to be localized to the distal portion of the long arm of human chromosome 18, within bands q22----q23. This chromosome locus is near the constitutive fragile site at band q21.3 on chromosome 18 associated with the 14;18 translocations seen in follicular lymphomas.
Activation of the met oncogene in the human MNNG-HOS cell line involves a chromosomal rearrangement.
In this study it is demonstrated that the activated met gene, which was originally detected in the MNNG-HOS chemically transformed human cell line, is a chimeric gene formed by the joining together of two distinct regions of DNA. Rearrangement of cellular DNA in MNNG-HOS cells was demonstrated by Southern analyses, which showed that the MNNG-HOS cell line contained unique met-related DNA fragments that were not detected in the parental cell line, HOS. Chromosomal localization using a series of rodent-human hybrid cell lines showed that the 5' end of the activated met gene is derived from human chromosome 1, in contrast to the 3' end of met which has been previously localized to human chromosome 7. The chimeric gene is transcribed to produce a 5-kb mRNA that is encoded both by regions of the gene derived from chromosome 1 and by regions of the gene derived from chromosome 7. Karyotype analysis of HOS and MNNG-HOS cells has identified several marker chromosomes that involve translocations of chromosomes 1 and 7. The possible location of the activated met locus within these rearranged chromosomes is discussed.
Divergent molecular phenotypes of KG1 and KG1a myeloid cell lines.
The cell line KG1 derived from a patient with erythroleukemia in myeloblastic relapse has the composite phenotype and functional repertoire of myeloblasts. In marked contrast, its subline KG1a has lost myeloid features, acquired new karyotypic markers, and has three characteristics associated with immature T cells: low-level expression of the T cell receptor beta mRNA (but not alpha) transcribed from a germline gene; high-level expression of T3 delta mRNA and intracellular, but not cell surface, T3 protein; and expression of the CD7/gp40 T cell-associated membrane antigen. Both KG1 and KG1a transcribe unrearranged IgH genes. These data suggest that either the KG1 cell line was derived from a common myeloid-lymphoid progenitor or that the KG1a subline phenotype is aberrant.
Long-term effects of chemotherapy on lymphocyte chromosomes from patients treated for gestational trophoblastic tumours.
A cytogenetic follow-up study of patients treated with chemotherapy for gestational trophoblastic tumours was undertaken. In some cases, high levels of chromosome damage were found to persist in lymphocytes for several years after completion of therapy. These results are compared with those found in similar studies of non-malignant and other malignant diseases. The relevance of these findings to the risk of subsequent chemotherapy-induced malignancy is discussed.
Long-term cytogenetic follow-up study of patients with uveitis treated with chlorambucil.
We have studied the long-term effects of chlorambucil treatment on the chromosomes of peripheral blood lymphocytes from patients with uveitis. Amounts of chromosome damage (breaks and rearrangements) were found to vary between individuals, but tended to increase with the cumulative dose. Some patients were found to have persistently high levels of chromosome damage many years after treatment had been completed.
Correlation of differentiation state and silver staining of nucleolar organizers in the promyelocytic leukemia cell line HL-60.
We have applied nucleolar organizer region (NOR) silver staining to the promyelocytic leukemia cell line HL-60, before and after dimethylsulfoxide (DMSO) mediated differentiation. The results demonstrated a gradual suppression of rDNA transcription during terminal maturation of these bone-marrow-derived cells and support our hypothesis that there are characteristic NOR staining profiles for different bone marrow cell types.
Variations in the activity of nucleolar organizers in different tissues, demonstrated by silver staining of human normal and leukemic cells.
A simple silver-staining technique that demonstrates those nucleolar organizing regions of metaphase chromosomes which are transcriptionally active during the preceding interphase (AgNORs) has been applied to cells obtained from the bone marrow and mitogen-stimulated peripheral blood lymphocyte cultures of hematologically normal individuals and patients with various forms of leukemia. In the majority of bone marrow cells from the normal controls and many of the patients, the number of cells with detectable AgNORs, and the staining intensities in those cells which were Ag+, were markedly reduced compared with the levels found in blood lymphocytes. The numbers of cells having satellite associations and the numbers of chromosomes participating in these associations also generally reflected the proportions of AgNORs present. When patterns of bone marrow silver staining were compared between patients with leukemia, distinct differences were found which could be correlated with cytology. It is suggested that different cell types have characteristic AgNOR staining profiles, reflecting specific regulation of ribosomal RNA synthesis in particular cell lineages. AgNOR staining may indicate, therefore, the predominant cell types that divide in the bone marrows of patients with different forms of leukemia.
The chromosome changes in non-Burkitt lymphomas.
Cytogenetic analysis of 26 non-Burkitt lymphomas having abnormal clones, revealed non-random involvement of certain chromosomes in numerical and structural changes. In some cases, chromosome structural abnormalities could be correlated with histopathology of the tumours. A combined analysis of cases in the present series, and from the literature, indicates that the most common aberrations in the lymphoproliferative disorders involve structural changes of chromosome 14.
Psychosocial outcome after coronary artery surgery.
To describe psychosocial adaptation after coronary artery surgery and to identify preoperative factors associated with good outcome, the authors interviewed 30 patients before and 1--2 years after surgery. Despite good physiologic outcome (as measured by treadmill and cardiac function) this sample was found to be functioning poorly. Eighty-three percent were unemployed, and 57% were sexually impaired. A preoperative duration of symptoms of eight months or more was associated with significantly worse postoperative overall adaptation. Most patients who had suffered angina eight months or longer evidenced a damaged self-concept, which was reinforced rather than repaired by the experience of surgery.
"Pre-B" phenotypes in blast crisis of Ph1 positive CML: evidence for a pluripotential stem cell "target".
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