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Biomedical subjects

A Skinner

Publications and source records attributed to A Skinner.

At least 19 recordsLinked to original sources

The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis.

The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose.

Benchmarking↗

Development and validation of an instrument to measure the postgraduate clinical learning and teaching educational environment for hospital-based junior doctors in the UK.

This paper describes the development and validation of a 40-item inventory, the Postgraduate Hospital Educational Environment Measure (PHEEM), by researchers in Scotland and the West Midlands using a combination of grounded theory and Delphi process. The instrument has since returned an alpha reliability >0.91 in two administrations in England and may be a useful instrument in the quality assurance process for postgraduate medical education and training.

Education, Medical, Graduate↗

Differences in conductance of M2 proton channels of two influenza viruses at low and high pH.

The M2 protein of influenza A viruses forms a proton channel involved in modifying virion and trans Golgi pH during infection. Previous studies of the proton current using whole-cell patch clamp of mouse erythroleukaemia (MEL) cells expressing the M2 protein of the "Weybridge" strain provided evidence for two protonation sites, one involved in permeation, the other in activation by acid pH. The present report compares the M2 channels of two different strains of influenza virus, "Weybridge" (WM2) and "Rostock" (RM2). Whereas with external acid pH the current-voltage relations showed similar small degrees of inward rectification, a similar apparent K(d) of approximately 10 microM for proton permeation and a high selectivity for protons over Na(+), the two M2 proteins differed in whole-cell conductance at low and high pH. The proton conductance of unit membrane area was on average 7-fold greater in RM2- than WM2-expressing MEL cells. At high external pH WM2 was shown previously to have small conductance for outward current at positive driving potential. In contrast, RM2 shows high conductance for outward current with high external pH, but shows small conductance for inward current with high internal pH, conditions in which WM2 shows high conductance for inward current. The different properties of the conductances due to the two channels at high pH were determined by three amino acids in their transmembrane domains. All intermediate mutants possessed one or other property and transformation of the WM2 phenotype into that of RM2 required substitution in all three residues V27I, F38L and D44N; single substitutions in RM2 effected the opposite phenotypic change. The significance of this difference for virus replication is not clear and it may be that the higher proton flux associated with RM2 is the main factor determining its increased ability to dissipate pH gradients. It is apparent, however, from the specific differences in the sidedness of the pH-induced changes in voltage dependence of the whole-cell current that this is an intrinsic property of the virus proton channel which may have parallels with regulation of other proton channels.

Animals↗

Supervision of trainee anaesthetists: a survey of opinions and practices.

This questionnaire survey investigated the different degrees of supervision of trainee anaesthetic senior house officers (SHOs) in hospitals across the United Kingdom, and compared it with past practices as well as with The Royal College of Anaesthetists' recommendations at that time. It is apparent that the duration of intensive supervision of new anaesthetic trainees has increased over the last 25 years. This study assesses these changes in order to evaluate whether or not these reforms have achieved their intended outcomes.

Anesthesiology↗

Improved incidental memory with nicotine after semantic processing, but not after phonological processing.

RATIONALE: A number of lines of evidence suggest that a nicotinic cholinergic system is mediating attentional processing. However, the evidence is less clear for a nicotinic system being involved in mnemonic processing. OBJECTIVES: The present study investigated the effects of nicotine on memory using a depth of processing paradigm. METHODS: A double-blind design was used with participants (n = 40) smoking either a nicotine containing cigarette (n = 20) and a denicotinized cigarette (n = 20). After smoking, each set of these participants was further subdivided into two groups (n = 10 for each). One group were presented with a series of trials each beginning with the presentation of a "decision word" which they had to say whether it represented something which was living or non-living (semantic-orienting). The second group had to say whether the word had one syllable or two syllables (phonological or non-semantic orienting condition). This decision was followed by a word in coloured ink whose colour participants were required to name as quickly as possible. On completion of the whole task the participants were given an unexpected free recall test. RESULTS: The nicotine-containing cigarette reduced the latencies for decision-making and colour naming in comparison with the denicotinized cigarette. The free recall test showed that nicotine-containing cigarette increased the number of words remembered, but only for the semantic-orienting condition and not the non-semantic condition. CONCLUSIONS: There is a nicotinic cholinergic system that mediates effortful processing. It can be deployed for attentional processing, including the associative processing required for memory encoding.

Adolescent↗

Social and demographic factors predictive of change over seven years in CHD-related behaviours in men aged 18-49 years.

It is possible that the relationship of social status to coronary heart disease is partly mediated through health-related behaviours that have been found to relate to both social status and CHD. Changes in certain health-related behaviours are known to lead to changes in CHD incidence. What are the characteristics of men who change or do not change these behaviours and their subsequent chances of CHD? This study aims to relate changes in men's CHD-related behaviours over a seven-year period to their social and demographic characteristics.A survey was carried out on a random sample of adults in Great Britain in 1984-85 and the equivalent information was obtained again on those participants who were re-interviewed seven years later in 1991-92. Results are presented for the 582 men aged 18-34 and the 584 men aged 35-49 at the first interview who were re-interviewed seven years later. Changes over the seven years in smoking, saturated fat intake, alcohol consumption and exercise were related to social and demographic factors. The two age groups showed broadly similar patterns of behaviour. In both age groups, those who continued with or took up a low fat diet and/or exercise were more likely to be in a higher social class, in employment, to live in private housing and to have more educational qualifications. For the younger men only, those in private housing were more likely to reduce the amount they smoked. Other findings are also reported. The findings suggest that those people who are in less advantageous social and economic situations are less likely to change to a more healthy lifestyle and so should be a focus for health education.

Adolescent↗

Neuregulin 1-alpha expression in locally advanced breast cancer.

The human Neuregulin 1 (NRG1) gene encodes several alternatively spliced ligands that bind to both c-erbB-3 and c-erbB-4, members of the family of type 1 tyrosine kinase growth factor receptors. Antibodies raised to a synthetic peptide recognize selectively the alpha variant of NRG1. The NRG1-alpha isoforms' expression was studied in 115 locally advanced adenocarcinomas of the breast using immunohistochemistry. Absent or low levels of NRG1-alpha were found to be associated with poorer prognosis compared to tumours that had moderate to high levels of the protein.

Journal Article↗

The sin of Onan.

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Bible↗

Levomepromazine for nausea and vomiting in advanced cancer.

Levomepromazine (previously known as methotrimeprazine), despite virtually no high quality scientific data to support its use, has become a very popular antiemetic for use in patients with advanced cancer. This article considers the reasons for this.

Dopamine Antagonists↗

Vital capacity and tidal volume preoxygenation with a mouthpiece.

We have measured oxygen wash-in in 20 volunteers undergoing preoxygenation with a face mask, mouthpiece alone and a mouthpiece with a noseclip, in a crossover study. Tidal volume breathing and maximal deep breath techniques were studied with each type of equipment. When tidal volume breathing was used, the face mask and mouthpiece with noseclip were comparable, but the mouthpiece alone achieved a lower end-expiratory oxygen concentration than the two other methods after 3 min (P < 0.001 and P < 0.01), and after 5 min (P < 0.05 in each case). Conversely, during preoxygenation with vital capacity breaths, the mouthpiece and mouthpiece with noseclip were comparable, and both were more effective than the face mask (P < 0.001). In a second study, 20 patients who had undergone preoxygenation before induction of anaesthesia were asked later if they would have preferred the face mask or mouthpiece for this procedure. Significantly more patients (14 of 18 who expressed a preference) favoured the mouthpiece (P < 0.05; confidence limits 0.56-0.92).

Cross-Over Studies↗

Holiday traumas.

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Accidents, Traffic↗

Chromosomal mapping of the human and mouse homologues of two new members of the AP-2 family of transcription factors.

The AP-2 transcription factor has been shown to play an important role in the development of tissues of ectodermal origin and has also been implicated in mammary oncogenesis. It has recently been found that AP-2 is encoded by a family of related genes, AP-2alpha, AP-2beta, and AP-2gamma. As a further step in understanding the role each of these genes has in development, we have used fluorescence in situ hybridization to map the chromosomal locations of the mouse and human homologues of the newly isolated AP-2beta and AP-2gamma genes. Tcfap2b and Tcfap2c map to mouse chromosomes 1A2-4 and 2H3-4, respectively, while TFAP2B and TFAP2C map to human chromosomes 6p12 and 20q13.2, the latter being a region that is frequently amplified in breast carcinoma.

Animals↗