Search PubMed⌕ Search

Biomedical subjects

B Heaton

Publications and source records attributed to B Heaton.

13 recordsLinked to original sources
PubMed1998

Field survey instrumentation and radioanalytical procedures for NORM.

The comprehensive monitoring and analysis of NORM is extremely difficult and involves a wide range of equipment and techniques. The instruments to be used can depend on both the national legislation of the country in which the measurements are being undertaken and the operational conditions under which they are carried out. These can dictate whether dose rate, alpha/beta contamination or gamma contamination measurements are taken. In some circumstances the total activity of the samples can be estimated using the gamma activities of the radionuclides present, while in others only full gamma and alpha spectral analysis will suffice.

Alpha Particles↗
PubMed1996

Occupational x-ray exposure of anaesthetists.

Lithium fluoride thermoluminescent dosimeter chips were used to measure the radiation dose received by anaesthetists caused by the use of image intensification during a typical 4-week period in an orthopaedic theatre. These were used to estimate an annual dose, for comparison with dose limits, to ascertain if anaesthetists should be included in personnel monitoring services. Doses proved to be below detectable limits; hence anaesthetists are at minimal risk from occupational exposure to radiation. The orthopaedic theatre is believed to use more x-rays than other theatres, so exposure elsewhere should also be undetectable.

Anesthesiology↗
PubMed1992

Analysis of chimeric mRNAs derived from the STE3 mRNA identifies multiple regions within yeast mRNAs that modulate mRNA decay.

In the yeast Saccharomyces cerevisiae unstable mRNAs decay 10-20 fold more rapidly than stable mRNAs. In order to examine the basis for the differences in decay rate of the unstable STE3 mRNA and the stable PGK1 and ACT1 mRNAs we have constructed and measured the decay rates of numerous chimeric mRNAs. These experiments indicate that multiple regions within yeast mRNAs are involved in modulating mRNA decay rates. Our results suggest that at least two regions within the STE3 mRNA are involved in stimulating rapid decay. One region is located within the coding region and requires sequences between codons 13 and 179. In addition, the STE3 3' UT can also function to stimulate decay. Surprisingly, the STE3 3' UT is not sufficient to accelerate the turnover of the stable PGK1 transcript unless portions of the PGK1 coding region are first deleted. These results not only identify sequences that function within yeast to stimulate mRNA turnover but also have important implications for an understanding of the basis of differences in eukaryotic mRNA decay rates.

Base Sequence↗
PubMed1991

Radiation: how real are the risks?

The risk from ionising radiations has recently been identified as being greater than it was previously thought to be. The data from which these new risk figures are drawn are outlined and their possible impact on the legislation controlling the use of ionising radiations is suggested. The likely new radiation dose limits are compared to the radiation doses which may be received in laboratories during normal operations using radionuclides, and the probable risk to arise from these doses is put into perspective.

Dose-Response Relationship, Radiation↗
PubMed1990

An evaluation of radiofrequency exposure from therapeutic diathermy equipment in the light of current recommendations.

Shortwave and microwave diathermy equipment use by physiotherapy departments in Grampian Region has been studied. Stray electric and magnetic fields close to equipment have been measured and compared with exposure levels recommended by the INIRC and the NRPB. Fields above the recommended whole body levels extend to 0.5-1.0 m from the electrodes and cables for continuous wave (cw) shortwave equipment, and up to 0.5 m for microwave units and pulsed shortwave models. Operators were exposed to local fields above these values for 2 - 3 min during cw shortwave treatments, but rarely exceeded the recommended exposure. However, short localised exposures to high fields, which can occur if the operator moves close to the electrodes or cables, could exceed these limits. Physiotherapists are advised to remain at a distance of at least 1 m during cw treatments, and not to approach within 0.5 m of the electrodes and cables even for a short period.

Diathermy↗
PubMed1989

Cesium-137, 134Cs and 110mAg in lambs grazing pasture in NE Scotland contaminated by Chernobyl fallout.

The decline in Cs radioisotope levels has been studied in tissues from lambs grazing lowland pasture. The lambs were slaughtered 18 and 115 d after contamination with Chernobyl fallout. During this time the Cs activity decreased to 13% of the initial amount in animals that had continued to graze contaminated pasture and to 3.5% in animals consuming uncontaminated feed. The 137Cs concentration in grass from the field grazed by the lambs decreased with a half-time of 22 d over the period 11-100 d after contamination. The amounts of Cs radionuclides removed from the pasture by the grazing animals amounted to only 0.01% of the total, the rest remaining in the soil, with over 40% in the upper 10 mm. Small amounts of 110mAg, found in grass, declined with a half-time of 8.9 d, and the radionuclide was found to accumulate in liver tissue.

Accidents↗
PubMed1979

Radiation dose to critical organs of staff and patients during neuroradiology.

The doses delivered to some critical organs of patients and staff during cerebral angiography, X-ray computer assisted tomographic scanning and 99Tcm brain scanning have been measured or assessed. The results show that doses received by staff and by the patients' gonads are generally quite low. However, patients having two or more of the investigations could receive skin and orbit doses in excess of 25 rad.

Brain↗