Biomedical subjects

S Bradshaw

Publications and source records attributed to S Bradshaw.

17 recordsLinked to original sources

PubMed1992

Sexual lifestyles and HIV risk.

Britain's first large, national survey of sexual attitudes and lifestyles will allow improved estimates of the magnitude of the HIV epidemic in Britain and should lead to better strategies for prevention.

Adolescent↗

PubMed1992

Mitogenic activity of epidermal growth factor on newborn rat astroglia: interaction with insulin-like growth factors.

Newborn rat astroglia cells possess epidermal growth factor (EGF) and insulin-like growth factor (IGF) receptors, which suggests that these growth factors regulate their growth and development. To determine the relative roles and interactions between the two growth factors on astroglial growth, primary cultures of astroglial cells from newborn rats (1 day postnatal) were treated with pure peptides, singly or in combination in various concentrations, and the growth response was determined by DNA synthesis ([3H]thymidine incorporation). EGF, IGF-I, and IGF-II, as single peptides, stimulated DNA synthesis, with half-maximal stimulatory concentrations of 0.25 ng/ml for EGF, 2.0 ng/ml for IGF-I, and 25 ng/ml for IGF-II, respectively. These findings indicate that astroglial cells are responsive to these growth factors in physiological concentrations, with the relative sensitivity of EGF greater than IGF greater than IGF-II. When EGF and IGF-I were added in combination, the growth stimulatory effect was greater than the additive effects of each growth factor added alone, indicating that the two growth factors act in synergism with each other. In particular, addition of increasing concentrations of EGF from 0.25-10 ng/ml to a constant concentration of 50 ng/ml IGF-I resulted in significant potentiation of [3H]thymidine incorporation of astroglial cells. To determine if the synergistic effect was due to a local synthesis of IGF-I by astroglia, a specific monoclonal antibody against IGF-I (Sm 1.2) was added to the peptides. Sm 1.2 decreased not only IGF-I-stimulated DNA synthesis, but also EGF-stimulated DNA synthesis, suggesting that the effects of EGF were contributed to in part by the local synthesis of IGF-I by astroglial cells. Analysis of conditioned medium from cells treated with EGF revealed a significant increase (approximately 2-fold) in IGF-I (from 4.5 to 8.8 ng/ml), but not IGF-II. To determine if the EGF effect on IGF synthesis was at the level of IGF-I mRNA transcription, stable IGF-I mRNA levels were determined in the astroglial cells before and after stimulation with EGF, using Northern analysis and quantification by densitometry. Astroglia expressed four IGF-I mRNA transcripts as in the adult and fetal liver, but only one (3.6 kilobases) IGF-II mRNA.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

The use of an universal wedge for asymmetric fields.

Beam collimators on newer linear accelerators may be collimated asymmetric to the central axis. The asymmetric beam has a non-flat profile adjusted to yield fields whose half widths are not symmetric about the central axis. While some treatment planning systems modify their programs to mimic the nonuniformity, ideally it is preferred to have a flat profile under the open beam. We have developed a universal wedge that can be used to flatten the field for a variety of jaw sizes and positions and energies for the Varian 2100C. The wedge flattens the field to +/- 3% over 80% of the field.

Humans↗

PubMed1978

Disability without handicap: so you think you've got problems?

Explore the source record for details and available documents.

Activities of Daily Living↗

PubMed1978

Metaphor as a diagnostic tool.

A case study is reported wherein the patient's frequent use of metaphors was used as presumptive evidence that the patient had been misdiagnosed ten years earlier as having central nervous system disease. The ability to produce metaphors depends upon the capacity to condense several meanings into a word or two, and this in turn implies a rather active associative process. Concretism, not associative richness, characterizes central nervous system disease. The presumption as regards diagnosis was supported by subsequent data including the patient's response to psychotherapy.

Alcohol Amnestic Disorder↗

PubMed1976