Search PubMed⌕ Search

Biomedical subjects

Roger Jones

Publications and source records attributed to Roger Jones.

15 recordsLinked to original sources
PubMed2003

Effect of ethnicity on performance in a final objective structured clinical examination: qualitative and quantitative study.

OBJECTIVE: To assess the effect of ethnicity on student performance in stations assessing communication skills within an objective structured clinical examination. DESIGN: Quantitative and qualitative study. SETTING: A final UK clinical examination consisting of a two day objective structured clinical examination with 22 stations. PARTICIPANTS: 82 students from ethnic minorities and 97 white students. MAIN OUTCOME MEASURES: Mean scores for stations (quantitative) and observations made using discourse analysis on selected communication stations (qualitative). RESULTS: Mean performance of students from ethnic minorities was significantly lower than that of white students for stations assessing communication skills on days 1 (67.0% (SD 6.8%) and 72.3% (7.6%); P=0.001) and 2 (65.2% (6.6%) and 69.5% (6.3%); P=0.003). No examples of overt discrimination were found in 309 video recordings. Transcriptions showed subtle differences in communication styles in some students from ethnic minorities who performed poorly. Examiners' assumptions about what is good communication may have contributed to differences in grading. CONCLUSIONS: There was no evidence of explicit discrimination between students from ethnic minorities and white students in the objective structured clinical examination. A small group of male students from ethnic minorities used particularly poorly rated communicative styles, and some subtle problems in assessing communication skills may have introduced bias. Tests need to reflect issues of diversity to ensure that students from ethnic minorities are not disadvantaged.

Clinical Competence↗
PubMed2003

K-ras gene sequence effects on the formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-DNA adducts.

The tobacco specific pulmonary carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is metabolically activated to electrophilic species that form methyl and pyridyloxobutyl adducts with genomic DNA, including O(6)-methylguanine, N7-methylguanine, and O(6)-[4-oxo-4-(3-pyridyl)butyl]guanine. If not repaired, these lesions could lead to mutations and the initiation of cancer. Previous studies used ligation-mediated polymerase chain reaction (LMPCR) in combination with PAGE to examine the distribution of NNK-induced strand breaks and alkali labile lesions (e.g., N7-methylguanine) within gene sequences. However, LMPCR cannot be used to establish the distribution patterns of highly promutagenic O(6)-methylguanine and O(6)-[4-oxo-4-(3-pyridyl)butyl]guanine adducts of NNK. We have developed methods based on stable isotope labeling HPLC-electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS) that enable us to accurately quantify NNK-induced adducts at defined sites within DNA sequences. In the present study, the formation of N7-methylguanine, O(6)-methylguanine, and O(6)-[4-oxo-4-(3-pyridyl)butyl]guanine adducts at specific positions within a K-ras gene-derived double-stranded DNA sequence (5'-G(1)G(2)AG(3)CTG(4)G(5)TG(6)G(7)CG(8)TA G(9)G(10)C-3') was investigated following treatment with activated NNK metabolites. All three lesions preferentially formed at the second position of codon 12 (GGT), the major mutational hotspot for G-->A and G-->T base substitutions observed in smoking-induced lung tumors. Therefore, our data support the involvement of NNK and other tobacco specific nitrosamines in mutagenesis and carcinogenesis.

Base Sequence↗
PubMed2003

A discourse analysis study of 'good' and 'poor' communication in an OSCE: a proposed new framework for teaching students.

BACKGROUND: There is still a great deal to be learnt about teaching and assessing undergraduate communication skills, particularly as formal teaching in this area expands. One approach is to use the summative assessments of these skills in formative ways. Discourse analysis of data collected from final year examinations sheds light on the grounds for assessing students as 'good' or 'poor' communicators. This approach can feed into the teaching/learning of communication skills in the undergraduate curriculum. SETTING: A final year UK medical school objective structured clinical examination (OSCE). METHODS: Four scenarios, designed to assess communication skills in challenging contexts, were included in the OSCE. Video recordings of all interactions at these stations were screened. A sample covering a range of good, average and poor performances were transcribed and analysed. Discourse analysis methods were used to identify 'key components of communicative style'. FINDINGS: Analysis revealed important differences in communicative styles between candidates who scored highly and those who did poorly. These related to: empathetic versus 'retractive' styles of communicating; the importance of thematically staging a consultation, and the impact of values and assumptions on the outcome of a consultation. CONCLUSION: Detailed discourse analysis sheds light on patterns of communicative style and provides an analytic language for students to raise awareness of their own communication. This challenges standard approaches to teaching communication and shows the value of using summative assessments in formative ways.

Clinical Competence↗
PubMed2002

Formation of benzo[a]pyrene diol epoxide-DNA adducts at specific guanines within K-ras and p53 gene sequences: stable isotope-labeling mass spectrometry approach.

The mutagenicity of a prominent tobacco carcinogen, benzo[a]pyrene (B[a]P), is believed to result from chemical reactions between its diol epoxide metabolite, (+)-anti-7r,8t-dihydroxy-c9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), and DNA, producing promutagenic lesions, e.g., (+)-trans-anti-7R,8S,9S-trihydroxy-10S-(N(2)-deoxyguanosyl)-7,8,9,10-tetrahydrobenzo[a]pyrene (N(2)-BPDE-dG). Previous studies used the DNA repair enzyme UvrABC endonuclease in combination with ligation-mediated PCR (LMPCR) to demonstrate an increased reactivity of BPDE toward guanine nucleobases within codons 157, 248, and 273 of the p53 tumor suppressor gene (Denissenko, M. F., Pao, A., Tang, M., and Pfeifer, G. P. Science 274, 430-432). These sites are also "hot spots" for mutations observed in lung tumors of smokers, suggesting an involvement of B[a]P in the initiation of lung cancer. However, the LMPCR approach relies on the ability of the repair enzyme to excise BPDE-induced lesions, and thus the slowly repaired lesions may escape detection. Furthermore, BPDE-DNA adduct structure and stereochemistry cannot be determined. In the present work, we performed a direct quantitative analysis of N(2)-BPDE-dG originating from specific guanine nucleobases within p53- and K-ras-derived DNA sequences by using a stable isotope labeling-mass spectrometry approach recently developed in our laboratory. (15)N-labeled dG was placed at defined positions within DNA sequences derived from the K-ras proto-oncogene and p53 tumor suppressor gene, the two genes most frequently mutated in smoking-induced lung cancer. (15)N-labeled DNA was annealed to the complementary strands, followed by BPDE treatment and liquid chromatography-electrospray ionization tandem mass spectrometry analysis (HPLC-ESI-MS/MS) of N(2)-BPDE-dG lesions. The extent of adduct formation at (15)N-labeled guanine was determined directly from the HPLC-ESI-MS/MS peak area ratios of (15)N-N(2)-BPDE-dG and N(2)-BPDE-dG. BPDE-induced guanine adducts were produced nonrandomly along K-ras and p53 gene-derived DNA sequences, with over 5-fold differences in adduct formation depending on sequence context. N(2)-BPDE-dG yield was enhanced by the presence of 5-Me substituent at the cytosine base-paired with the target guanine nucleobase, an endogenous DNA modification characteristic for CpG dinucleotides within the p53 gene. In the K-ras-derived DNA sequence, the majority of N(2)-BPDE-dG adducts originated from the first position of the codon 12 (GGT), consistent with the large number of G --> T transversions observed at this nucleotide in smoking-induced lung cancer. On the contrary, the pattern of N(2)-BPDE-dG formation within the p53 exon 5 sequences did not correlate with the mutational spectrum in lung cancer, suggesting that factors other than N(2)-BPDE-dG formation are responsible for these mutations. The stable isotope labeling HPLC-ESI-MS/MS approach described in this work is universally applicable to studies of modifications to isolated DNA by other carcinogens and alkylating drugs.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed2002

The effects of large-scale afforestation and climate change on water allocation in the Macquarie River catchment, NSW, Australia.

Widespread afforestation has been proposed as one means of addressing the increasing dryland and stream salinity problem in Australia. However, modelling results presented here suggest that large-scale tree planting will substantially reduce river flows and impose costs on downstream water users if planted in areas of high runoff yield. Streamflow reductions in the Macquarie River, NSW, Australia are estimated for a number of tree planting scenarios and global warming forecasts. The modelling framework includes the Sacramento rainfall-runoff model and IQQM, a streamflow routing tool, as well as various global climate model outputs from which daily rainfall and potential evaporation data files have been generated in OzClim, a climate scenario generator. For a 10% increase in tree cover in the headwaters of the Macquarie, we estimate a 17% reduction in inflows to Burrendong Dam. The drying trend for a mid-range scenario of regional rainfall and potential evaporation caused by a global warming of 0.5 degree C may cause an additional 5% reduction in 2030. These flow reductions will decrease the frequency of bird-breeding events in Macquarie Marshes (a RAMSAR protected wetland) and reduce the security of supply to irrigation areas downstream. Inter-decadal climate variability is predicted to have a very significant influence on catchment hydrologic behaviour. A further 20% reduction in flows from the long-term historical mean is possible, should we move into an extended period of below average rainfall years, such as occurred in eastern Australia between 1890 and 1948. Because current consumptive water use is largely adapted to the wetter conditions of post 1949, a return to prolonged dry periods would cause significant environmental stress given the agricultural and domestic water developments that have been instituted.

Agriculture↗
PubMed2002

General practitioners with special clinical interests: a cross-sectional survey.

A survey was conducted to identify general practitioners with special clinical interests (GPSCIs) and to obtain views about their role. Approximately, 16% of GPs in the United Kingdom (n = 4000) provide specialist clinical services outside their core general practice commitments. This pool of expertise has important implications for the implementation of the NHS Plan and for workforce planning within primary care trusts.

Cross-Sectional Studies↗