Biomedical subjects

B Beresford

Publications and source records attributed to B Beresford.

7 recordsLinked to original sources

PubMed2004

On the road to nowhere? Young disabled people and transition.

BACKGROUND: A key issue, and one known to be highly problematic and challenging, concerns the transition of young disabled people from children's services to adult services, and from childhood to adulthood. To inform its recommendations on this issue, the Disabled Children's External Working Group (EWG) for the Children's NSF commissioned a review of research on young disabled people and transition. METHODS: Given the preponderance of grey literature in this area, database searches were supplemented by hand searching of key journals and contacts with key individuals, research units, publishers and funding bodies in order to identify relevant literature on the experiences of transition from the perspectives of young people, parents and practitioners; the outcomes of transition; and evaluations of services provided during this life-stage. RESULTS: The evidence available with regard to transitions of young disabled people provides a clear and consistent picture of the way transitions are currently experienced by young disabled people and their families. There is limited evidence on what works to ensure smooth transitions between services and positive outcomes of transition for the young people themselves. CONCLUSIONS: Existing research is very persuasive on the need to improve transitions for young disabled people. It can also be used to provide clues as to the sorts of support and service configurations that need to be in place to ensure positive transitions. However, further research is needed both at the level of specific service/service model evaluation as well as holistic, longitudinal work to provide evidence on the long-term outcomes of young disabled people as they move into adulthood.

Adolescent↗

PubMed1995

The spatial accuracy of cellular dose estimates obtained from 3D reconstructed serial tissue autoradiographs.

In order to better predict and understand the effects of radiopharmaceuticals used for therapy, it is necessary to determine more accurately the radiation absorbed dose to cells in tissue. Using thin-section autoradiography, the spatial distribution of sources relative to the cells can be obtained from a single section with micrometre resolution. By collecting and analysing serial sections, the 3D microscopic distribution of radionuclide relative to the cellular histology, and therefore the dose rate distribution, can be established. In this paper, a method of 3D reconstruction of serial sections is proposed, and measurements are reported of (i) the accuracy and reproducibility of quantitative autoradiography and (ii) the spatial precision with which tissue features from one section can be related to adjacent sections. Uncertainties in the activity determination for the specimen result from activity losses during tissue processing (4-11%), and the variation of grain count per unit activity between batches of serial sections (6-25%). Correlation of the section activity to grain count densities showed deviations ranging from 6-34%. The spatial alignment uncertainties were assessed using nylon fibre fiduciary markers incorporated into the tissue block, and compared to those for alignment based on internal tissue landmarks. The standard deviation for the variation in nylon fibre fiduciary alignment was measured to be 41 microns cm-1, compared to 69 microns cm-1 when internal tissue histology landmarks were used. In addition, tissue shrinkage during histological processing of up to 10% was observed. The implications of these measured activity and spatial distribution uncertainties upon the estimate of cellular dose rate distribution depends upon the range of the radiation emissions. For long-range beta particles, uncertainties in both the activity and spatial distribution translate linearly to the uncertainty in dose rate of < 15%. For short-range emitters (< 100 microns), such as alpha particle sources, the magnitude of the uncertainty in serial section alignment is comparable with the particle track length. Under these circumstances, dosimetric errors are introduced in proportion to the serial section alignment inaccuracy.

Animals↗

PubMed1992

Death certification in Western Australia--classification of major errors in certificate completion.

We aimed to develop a method to classify those errors in the completion of death certificates arising from misunderstanding of the certification process. We reviewed 430 Western Australian death certificates registered in March 1990 using a method devised to differentiate between major and minor errors. Major errors were found in 16 per cent of certificates (95 per cent confidence interval 12 to 20 per cent). The error rate did not vary significantly between city and country areas, nor between teaching hospitals and other locations. The method was validated on a separate sample of 120 certificates. It has potential as a tool to monitor a critical but neglected step in the production of mortality statistics and to assess understanding of the process of death certification.

Death Certificates↗

PubMed1992

Cellular kinetics, dosimetry, and radiobiology of alpha-particle radioimmunotherapy: induction of apoptosis.

Though clinical results for radioimmunoconjugate therapy of most common epithelial tumors have been disappointing, dramatic responses have been observed repeatedly in the treatment of high- and low-grade malignant lymphomas. This high clinical responsiveness after radioimmunoconjugate therapy sometimes appears to be out of proportion to the calculated radiation dose absorbed by the lymphoma tissue. Here we describe some key aspects of the kinetics, dosimetry, and cellular radiobiology of murine lymphoma cells exposed to 212Bi-radiolabeled alpha-particle-emitting immunoconjugates specific for the differentiation antigen Thy 1.2. Approximately 25 cell-bound alpha-particle-emitting immunoconjugates per target cell were required to reduce clonogenic survival by 90% (the radiobiological D10). Serial kinetic analyses of the antibody and radioisotope components of the immunoconjugates revealed significant levels of dechelation and up to 7.5% cellular internalization of the isotope. Cellular radiation dosimetry performed by Monte Carlo computer simulation of alpha-particle energy deposition patterns based on the observed radiopharmacokinetics showed that the D10 resulted from approximately four alpha-particle traversals through the nucleus, corresponding to an absorbed radiation dose of approximately 0.95 Gy to the cell nucleus. Electron micrographs and DNA gel studies of murine lymphoma cells undergoing radioimmunoconjugate therapy in vivo and in vitro demonstrated bizarre blebbing patterns, condensation of chromosomal material, and internucleosomal DNA fragmentation patterns characteristic of programmed cell death (apoptosis). We conjecture that the efficacy of radioimmunoconjugates against responsive cell types may be the result of passive DNA damage by ionizing radiation and the initiation of apoptosis in response to radioimmunotherapy.

Alpha Particles↗

PubMed1991

Radiation hormesis.

"Radiation hormesis" is the name given to the putative stimulatory effects of low level ionizing radiation (generally in the range of 1-50 cGy of low-LET radiation). Based on historical and pharmacologic principles reminiscent of some of the major tenets of homeopathy, most of these effects are now generally ascribed to protective feedback systems that, upon exposure to low concentrations of toxins, proceed to stimulate metabolic detoxification and repair networks. The activation of these networks may then result in net beneficial effects on the cell, organism or species. Discussions of possible stimulatory effects of low levels of ionizing radiation have recently become entangled with the separate but related question of whether a threshold dose level exists on the radiotoxicologic dose-response curve. This review summarizes some of the relevant historical and scientific data bearing on the question of radiation hormesis. We find the data in support of most of the hormesis postulates intriguing but inconclusive.

Dose-Response Relationship, Radiation↗

PubMed1983

Brachial muscles in the chick embryo: the fate of individual somites.

The wing and wing-associated muscles of the shoulder and thorax in the bird all cleave from common myogenic masses in the developing wing bud and are referred to collectively as brachial muscles. In this study the precise embryonic origin of the brachial muscles was determined using chick-quail chimaeras. Such chimaeras consisted of a graft of one somite taken from a 2-day quail donor embryo transplanted to the equivalent location in a 2-day chick host embryo. The chimaeras were analysed at 9.5-10.0 days in ovo to determine the location of the grafted cells and therefore the structures that were derived from the transplanted somite. The somites that were studied in this matter were somites 13 to 23 inclusive. The results show that only somites 16 to 21 inclusive contribute cells to the brachial musculature; moreover, the cells from a given somite are not distributed randomly among the brachial muscles but populate specific muscles only: thus it has been possible to map the somitic origin of individual brachial muscles. Moreover, there is an indication that each somite plays a unique role in the development of the brachial muscles.

Animals↗

PubMed1978

Chimaera studies of the origin and formation of the pectoral musculature of the avian embryo.

Cervical, brachial, and thoracic somites and brachial somatopleure were transplanted from quail into 2-day chick embryos to determine their contribution to the formation of the pectoralis major muscle. The results show that the musculature of the pectoralis major and pectoralis minor is derived entirely from brachial somites (16-20) while the brachial somatopleure provides much of the connective tissue of these muscles. Migration of somitic cells into the somatopleure appears to begin before the somites are fully formed. The primordium of the pectoralis muscle forms at the base of the wing bud and extends ventro-caudally into the thoracic area to attach to the sternum.

Animals↗