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Biomedical subjects

M Bradley

Publications and source records attributed to M Bradley.

At least 19 recordsLinked to original sources
PubMed2001

Site distribution in resin beads as determined by confocal Raman spectroscopy.

Scanning confocal Raman spectroscopy was used to study the distribution of reactive sites within a resin bead used for solid-phase synthesis. The distribution of NH2 groups in aminomethylated polystyrene resin (APS) was determined by doping with varying amounts of 4-cyanobenzoic acid. The extent of loading was determined by both elemental analysis and ninhydrin assays. The spatial distribution of the coupled 4-cyanobenzamide within the bead was determined to an in-plane resolution of 1 microm and depth resolution of about 4 microm, using the strong Raman CN stretching vibrational transition at 2230 cm(-1). Dry and swollen beads were studied and the distribution was found to be essentially uniform throughout the bead in all cases.

Journal Article↗
PubMed2001

Birt-Hogg-Dubé syndrome: mapping of a novel hereditary neoplasia gene to chromosome 17p12-q11.2.

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant neoplasia syndrome characterized mainly by benign skin tumors, and to a lesser extent, renal tumors and spontaneous pneumothorax. To map the BHD locus, we performed a genome-wide linkage analysis using polymorphic microsatellite markers on a large Swedish BHD family. Evidence of linkage was identified on chromosome 17p12-q11.2, with a maximum LOD score of 3.58 for marker D17S1852. Further haplotype analysis defined a approximately 35 cM candidate interval between the two flanking markers, D17S1791 and D17S798. This information will facilitate the identification of the BHD gene, leading to the understanding of its underlying molecular etiology.

Carcinoma, Renal Cell↗
PubMed2001

Linkage and association to candidate regions in Swedish atopic dermatitis families.

We have studied, in 406 families with at least two siblings affected with atopic dermatitis (in total 1514 individuals) from the Swedish population, linkage and association to five chromosomal regions (2q35, 5q31-33, 6p21, 11q13 and 14q11) previously implicated in atopic diseases. The region on 14q11 gave evidence for linkage to atopic dermatitis (NPL-score: 2.36, P<0.009). In the 11q13 region, there was a clear association to an intragenic marker in the beta-subunit of the high-affinity IgE receptor for raised allergen-specific serum IgE levels (P<0.009). When a quantitative variable for the severity of atopic dermatitis was studied, evidence was found in favour of linkage to the 5q31-33 region, with the highest Z-score (2.06) close to the marker D5S458 (P<0.005).

Age of Onset↗
PubMed2001

In-vitro visualization of biopsy needles with ultrasound: a comparative study of standard and echogenic needles using an ultrasound phantom.

AIM: To demonstrate the circumstances where echogenically enhanced biopsy needles confer an increase in visualization during ultrasound-guided biopsy using an in-vitro experiment. MATERIALS AND METHODS: An experiment using both standard and echogenically enhanced needles was conducted in a purpose built interventional phantom. The needle tip echogenicity and shaft visualization was recorded at different angles (20 and 60 degrees ) between the ultrasound probe and needle. The needle tip echogenicity was also recorded in four different angles of bevel rotation. The experiment was performed using a total of 18 different needles of 18 and 20 gauge. RESULTS: The experiment confirmed some previous findings. The needle was better visualised at an angle of approximately 60 degrees to the probe. The needle tip was optimally visualized with the bevel facing the transducer or 180 degrees to it. Needle tip movement improved conspicuity. Using an optimal angle of approach (60 degrees ) the use of an echogenic needle did not confer any increase in conspicuity. If the transducer to needle angle was suboptimal (20 degrees ) then there was increased visualization of some echogenically enhanced needles. CONCLUSION: Optimisation of the conditions prior to ultrasound-guided needle biopsy will increase the visualization of the chosen device thus aiding the interventionalist. Needle gauge, bevel position, movement of the needle and the probe to needle angle all affect conspicuity. Needle coating or roughening does not improve tip visualization if the angle between the needle and probe can be optimized (60 degrees ). In unfavourable situations when the angle is suboptimal (20 degrees ), we have shown that echogenic enhancement of the needle tip can make it more visible.

Biopsy, Needle↗
PubMed2001

Physician perceptions of a national formulary.

OBJECTIVE: To assess the perceptions of US Department of Veterans Affairs (VA) physicians regarding effects of a National Formulary (NF) on patient care, access to drugs, physician workload, and resident training approximately 1 year after it was implemented. STUDY DESIGN: Cross-sectional survey. METHODS: A questionnaire was sent to attending physicians working within the VA healthcare system. Participants included general internists (n = 2824), neurologists (n = 238), psychiatrists (n = 997), general surgeons (n = 429), and urologists (n = 152). The response rate was 45%. RESULTS: Most physicians (63%) thought that they could prescribe needed drugs; 65% agreed that patients could obtain needed nonformulary drugs. One third disagreed that access to prescription pharmaceuticals had increased; 29% stated the NF impinged on providing quality care to their own patients, and 21% thought it did so to patients from other VA facilities. Thirty eight percent of physicians perceived the NF to be more restrictive than private sector formularies; 16% thought that the NF diminished the ability to train residents for managed care. Forty percent thought that the NF added to workload. Generalists more often perceived that the NF improved their ability to provide care compared with neurologists (27% vs 18%, P = .046), psychiatrists (27% vs 22%, P = .027), and internal medicine subspecialists (27% vs 18%, P = .001). Physicians with more clinic time were more likely to perceive that the NF increased workload. CONCLUSION: Although differences of opinions among physicians were noted, most responding VA physicians did not perceive that the NF adversely affected patient care, access to pharmaceuticals, physician workload, or resident training.

Attitude of Health Personnel↗
PubMed2000

Optimising inhibitors of trypanothione reductase using solid-phase chemistry.

A series of inhibitors of the enzyme trypanothione reductase has been identified using directed solid-phase chemistry. The compounds were based on a series of polyamine scaffolds and used the natural product kukoamine A as the lead structure. A compound with a Ki of 76 nM was identified, although somewhat surprisingly the compound appeared to be noncompetitive in nature.

Animals↗
PubMed2000

Systematic review of water fluoridation.

OBJECTIVE: To review the safety and efficacy of fluoridation of drinking water. DESIGN: Search of 25 electronic databases and world wide web. Relevant journals hand searched; further information requested from authors. Inclusion criteria were a predefined hierarchy of evidence and objectives. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity. MAIN OUTCOME MEASURES: Decayed, missing, and filled primary/permanent teeth. Proportion of children without caries. Measure of effect was the difference in change in prevalence of caries from baseline to final examination in fluoridated compared with control areas. For potential adverse effects, all outcomes reported were used. RESULTS: 214 studies were included. The quality of studies was low to moderate. Water fluoridation was associated with an increased proportion of children without caries and a reduction in the number of teeth affected by caries. The range (median) of mean differences in the proportion of children without caries was -5.0% to 64% (14.6%). The range (median) of mean change in decayed, missing, and filled primary/permanent teeth was 0.5 to 4.4 (2.25) teeth. A dose-dependent increase in dental fluorosis was found. At a fluoride level of 1 ppm an estimated 12.5% (95% confidence interval 7.0% to 21.5%) of exposed people would have fluorosis that they would find aesthetically concerning. CONCLUSIONS: The evidence of a beneficial reduction in caries should be considered together with the increased prevalence of dental fluorosis. There was no clear evidence of other potential adverse effects.

Child↗
PubMed2000

Biomimetic synthesis of lantibiotics.

The lantibiotics are a class of highly posttranslationally modified small peptide antibiotics containing numerous lanthionine and dehydroamino acid residues. We have prepared peptides containing multiple dehydroamino acids and cysteine residues in order to probe the biomimetic synthesis of the lantibiotics from their precursor peptides. A novel synthetic methodology was developed to allow the synthesis of multiple dehydroamino acid containing peptides. Cyclisations were rapid, quantitative and regiospecific. Remarkably the peptide sequences alone appear to contain sufficient information to direct a series of stereo- and regiospecific ring closures. Thus both the two linear peptides for the B and E-rings closed stereoselectively. In the case of the A-ring precursor peptide which contained two dehydroamino acids, cyclisation was again totally regioselective, although not totally stereoselective.

Alanine↗
PubMed2000

Polymer-based materials to be used as the active element in microsensors: a scanning force microscopy study

Polymer-based materials can be incorporated as the active sensing elements in chemiresistor devices. Most of these devices take advantage of the fact that certain polymers will swell when exposed to gaseous analytes. To measure this response, a conducting material such as carbon black is incorporated within the nonconducting polymer matrix. In response to analytes, polymer swelling results in a measurable change in the conductivity of the polymer/carbon composite material. Arrays of these sensors may be used in conjunction with pattern recognition techniques for purposes of analyte recognition and quantification. We have used the technique of scanning force microscopy (SFM) to investigate microstructural changes in carbon-polymer composites formed from the polymers poly (isobutylene) (PIB), poly (vinyl alcohol) (PVA), and poly (ethylene-vinyl acetate) (PEVA) when exposed to the analytes hexane, toluene, water, ethanol, and acetone. Using phase-contrast imaging (PI), changes in the carbon nanoparticle distribution on the surface of the polymer matrix are measured as the polymers are exposed to the analytes in vapor phase. In some but not all cases, the changes were reversible (at the scale of the SFM measurements) upon removal of the analyte vapor. In this paper, we also describe a new type of microsensor based on piezoresistive microcantilever technology. With these new devices, polymeric volume changes accompanying exposure to analyte vapor are measured directly by a piezoresistive microcantilever in direct contact with the polymer. These devices may offer a number of advantages over standard chemiresistor-based sensors.

Journal Article↗
PubMed2000

Drug treatment of hypertension in older people: relieving the pressure.

Hypertension is very common, occurring in over 50% of older people, and is a major risk factor for stroke and ischaemic heart disease. Based on systematic reviews there is evidence to show that drug treatment of hypertension in older people saves lives and prevents unnecessary morbidity. There is also strong evidence to support the use of diuretics as first line agents. Quality of life does not appear to be reduced by antihypertensive drug therapy, although more high quality research is needed. Through the use of drug treatment older people with hypertension can continue to contribute to society and live active lives.

Aged↗
PubMed2000

A safety-catch linker for amine release under biologically compatible conditions.

A 'biocompatible' safety-catch linker based on an internal diketopiperazine release has been developed to allow the release of amine based compounds. The synthesis of the linker and its pre-loading with a representative set of amines is described. After immobilization onto an amino Tentagel resin, the linker was activated and the amines were released under biological conditions at pH 8.

Amines↗
PubMed2000

Tackling inequalities in health and social wellbeing: evidence of 'good practice' by nurses, midwives and health visitors.

This paper details a project which assessed the contribution made by nurses, midwives and health visitors to Targeting Health and Social Need (THSN). Targeting Health and Social Need is an important theme within the Northern Ireland Regional Strategy entitled Health and Wellbeing into the Next Millennium: A Regional Strategy for Health and Social Wellbeing 1997-2002 which is concerned with addressing inequalities in health status and social wellbeing. While there is a considerable body of research and information on variations in health and social wellbeing there is a paucity of corresponding research on those interventions which may improve the health of disadvantaged groups. Health professionals are addressing such inequalities so it is appropriate that their efforts should be recorded and assessed. The project was conducted jointly by the departments of nursing at The Queen's University of Belfast and the University of Ulster, funded by the Department of Health and Social Services and had a timetable that covered three phases. Phase 1 entailed the distribution of a survey questionnaire to all nurses, including those professionals working with community and voluntary groups, to assess their contribution to THSN. The paper describes the results from the 392 questionnaires identified (a response rate of almost 40%) and the work in phase 2 of analysing the responses by selection criteria devised by the Project Advisory Board to allow further investigation. The resulting interventions were reduced to 22 and in an overview of each of these a number of characteristics kept recurring that could serve to define aspects of 'good practice'. These 22 case studies demonstrate the efforts made by nurses and health professionals to change behaviour, practice, the community and the environment. Also highlighted are the nursing competencies gained through working, the lessons learnt and the problems and difficulties encountered. The paper concludes that the use of qualitative research opens the door to measures of social position that reflect the ways in which people define themselves and the relationships that sustain them. Although there is still some way to go in understanding the different approaches to evaluation, an environment that fosters the monitoring and assessment of practice might be created in the future within the nursing community.

Community Health Nursing↗
PubMed2000

D-dimer assay for deep vein thrombosis: its role with colour Doppler sonography.

AIM: To evaluate the role of a negative D-dimer assay in the initial management of patients with clinically suspected deep venous thrombosis (DVT), using colour Doppler ultrasound as the primary diagnostic technique. MATERIALS AND METHODS: A double-blind prospective trial was performed on 143 patients with clinically suspected DVT. All patients underwent a D-dimer assay prior to anticoagulant therapy. DVT was confirmed or excluded by diagnostic colour Doppler ultrasound within 24 h of presentation. RESULTS: In nearly one-third of the cases (31.8%), Doppler ultrasound was positive. The D-dimer assay demonstrated a sensitivity of 97.7% with only one false-negative, but the specificity was low at 48.9% with 45 false-positive results. The positive predictive value for D-dimer assay was 48.8%, whilst the important negative predictive value was 98%. CONCLUSION: If D-dimer was used to screen for DVT, and patients with negative results were not imaged, then the imaging workload could be reduced by 35%. In this study one small calf vein thrombus would have been missed by adopting this practice.Bradley, M. (2000). Clinical Radiology 55, 525-527.

Adolescent↗