D. G. Papworth

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We have demonstrated chromosomal instability in the clonal descendants of hemopoietic stem cells after irradiating murine bone marrow with alpha-particles. However, because cells that are irradiated by alpha-particles are defined by a Poisson distribution of individual particle traversals, there is an inevitable proportion of unirradiated cells in the(More)
Genomic imprinting brings about allele-specific silencing according to parental origin. Silencing is controlled by cis-acting regulatory regions that are differentially marked during gametogenesis and can act over hundreds of kilobases to silence many genes. Two candidate imprinting control regions (ICRs) have been identified at the compact imprinted Gnas(More)
Two aspects of the relationship between Asymmetrical (A) and Symmetrical (S) radiation-induced chromosomal aberrations are considered in this paper. (1) Are A and S truly alternative modes of lesion interactions? Relative frequencies for chromatid-type and chromosome-type are examined, and new lymphocyte data using banding is used to look at this, and also(More)
PURPOSE To detect simple, pseudosimple and complex chromosome exchanges in X-ray-induced aberrations involving two distinctly painted chromosomes. Each visibly complex two-paint exchange was analysed to determine the number of breaks and chromosomes necessary to derive the pattern. In addition, the number of associated paint junctions was scored to assess(More)
The kinetics of replication for early and late replicating X chromosomes in karyotypically normal fibroblasts and lymphocytes was studied using terminal bromodeoxyuridine (BrdU) treatment followed by Hoechst/light/Giemsa staining. Although the order of band appearance differs between the two tissues, the programme (order and interval between band(More)
Intranuclear DNA synthesis and concomitant chromosome duplication occur during a discrete period of the cell cycle termed S-phase. Using replication-banding and serial time sampling in asynchronous cell populations, it is possible to subdivide the S-phase into four or five chronological compartments termed "subphases". This paper discusses methods for(More)
1. The role of uptake across the brush border in the intestinal absorption of calcium has been studied by examining the kinetics of influx into slices of rat intestine in vitro. Both mucosal and serosal surfaces were exposed to the medium.2. The rate of influx was accurately defined by a two-component expression comprising a saturable (Michaelis-Menten)(More)
The form of the dose-response for induction of malignant diseases in vivo by ionizing radiation is not yet established in spite of its scientific interest and its practical importance. Considerably extended observations have confirmed that the dose-response for acute myeloid leukaemia induced in male CBA/H mice by X-ray exposure is highly curvilinear. The(More)