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Biomedical subjects

M I Jones

Publications and source records attributed to M I Jones.

10 recordsLinked to original sources
PubMed2001

Prescribing new drugs: qualitative study of influences on consultants and general practitioners.

OBJECTIVE: To explore consultants' and general practitioners' perceptions of the factors that influence their decisions to introduce new drugs into their clinical practice. DESIGN: Qualitative study using semistructured interviews. Monitoring of hospital and general practice prescribing data for eight new drugs. SETTING: Teaching hospital and nearby general hospital plus general practices in Birmingham. PARTICIPANTS: 38 consultants and 56 general practitioners who regularly referred to the teaching hospital. MAIN OUTCOME MEASURES: Reasons for prescribing a new drug; sources of information used for new drugs; extent of contact between consultants and general practitioners; and amount of study drugs used in hospitals and by general practitioners. RESULTS: Consultants usually prescribed new drugs only in their specialty, used few new drugs, and used scientific evidence to inform their decisions. General practitioners generally prescribed more new drugs and for a wider range of conditions, but their approach varied considerably both between general practitioners and between drugs for the same general practitioner. Drug company representatives were an important source of information for general practitioners. Prescribing data were consistent with statements made by respondents. CONCLUSIONS: The factors influencing the introduction of new drugs, particularly in primary care, are more multiple and complex than suggested by early theories of drug innovation. Early experience of using a new drug seems to strongly influence future use.

Drug Industry↗
PubMed2001

Proton pump inhibitors: a study of GPs' prescribing.

BACKGROUND: There has been a rapid increase in proton pump inhibitor (PPI) prescribing in recent years, and controlling the cost and improving the quality of prescribing is an issue of concern to many GPS: OBJECTIVE: Our aim was to compare GPs' usage of different PPIs and explore how GPs' PPI prescribing changes following the introduction of a cheaper competitor. METHODS: PPI prescribing data (PACT) for 53 GPs, who were selected as regular users of a teaching hospital, were monitored from January 1995 to December 1997. The GPs were located in two adjoining health districts and had been interviewed about influences on their decisions to begin prescribing lansoprazole. The PPI prescribing data were collected for the teaching hospital and the general hospital in the adjoining district. RESULTS: Complete prescribing data were available for 50 GPS: Total PPI prescribing increased throughout the study due mainly to increasing use of the new PPIS: Use of the new PPIs increased from 6 to 24% over 3 years. The proportion of maintenance doses prescribed increased from 3 to 12%. There was a 23-fold difference in total PPI prescribing and an 87-fold difference in lansoprazole prescribing between the highest and lowest prescribers. The uptake of pantoprazole was slower than that of lansoprazole. A rapid increase in the use of lansoprazole by the GPs followed an increase in use in the teaching hospital. CONCLUSION: Hospital prescribing was an important influence on the choice of PPI used by GPS: The wide variation in PPI prescribing suggests that there is scope for improvement in the quality and cost of PPI prescribing.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2000

Protein adsorption and platelet attachment and activation, on TiN, TiC, and DLC coatings on titanium for cardiovascular applications.

The hemocompatibility of a TiN/TiC/diamond-like carbon (DLC) multilayer structure, deposited on titanium substrates for use as coatings for a heart valve prosthesis, has been studied through the adsorption of blood proteins and the adhesion and attachment of blood platelets. All of the surfaces were characterized by stylus profilometry and water contact angles. The adsorption of albumin and fibrinogen to the surfaces was assessed using the Amido Black assay, whereas platelet attachment was studied by scanning electron microscopy and quantified using stereological techniques. The degree of platelet spreading on the surfaces was seen to correlate with differences in surface energy, indicated from contact angle measurements. The greatest spreading was seen on the more hydrophilic surfaces. When studying protein adsorption to the surfaces, no correlation could be determined between contact angle results and levels of adsorption, although the most hydrophilic surfaces did appear to promote greater amounts of fibrinogen adsorption. Thrombus formation was observed to some degree on all of the surfaces, with the exception of the DLC coating. This coating also promoted less spreading of platelets than the other surfaces. The good hemocompatibility of the DLC coating is attributed to its hydrophobicity and smooth surface, resulting in a higher ratio of albumin to fibrinogen than any of the other surfaces.

Cardiovascular System↗
PubMed2000

European survey of primary care physician perceptions on heart failure diagnosis and management (Euro-HF).

AIMS: To survey a random sample of primary care physicians across six European countries regarding their perceptions of diagnostic and prescribing issues in heart failure, and to consider factors that might be associated with physician under-performance. METHODS AND RESULTS: Qualitative, postal questionnaire-based, validated survey in the native tongue of a random sample of 200 primary care physicians in each of five European countries (France, Germany, Italy, The Netherlands and Spain) and of 250 U.K. primary care physicians. Respondents provided: details of practice characteristics; the usual way a diagnosis of heart failure was established; access to investigations; names of drugs prescribed in heart failure, with estimates of the proportion of patients supplied with particular classes; and physician attitudes regarding the evidence base (in terms of benefits and risks) for treatments used. Outcomes were physician perceptions and attitudes about heart failure diagnosis and treatment. Adjusted response rates varied from 17% (France) to 56% (Britain). Primary care physicians underestimate the prevalence of heart failure. Most patients are diagnosed on symptoms and signs alone, with only 32% having further investigations or referral. Although most primary care physicians stated they prescribe ACE inhibitors in heart failure, this was for only 47-62% of patients, and at doses below those identified as effective in trials. Most prescribing doctors (91%) believe there is strong evidence of reduced mortality in heart failure patients using ACE inhibitors, but 51% also consider ACE inhibitors have substantial risks with their use. CONCLUSION: Limitations of the data include the general problem of questionnaires, whether responses accord with actual clinical practice, and, specific to these data, the low response rate in some countries (although the study does provide information from nearly 300 randomly selected primary care physicians across Europe). New preliminary insights include exposition of the 'low tech' approach to heart failure diagnosis across Europe: doctors report the use of symptoms and signs alone; the lack of direct (open) access to objective investigations, such as echocardiography, which almost guarantees that misdiagnoses will occur; and the under-utilization and under-dosing with ACE inhibitors. The main factor influencing under-use would appear to be the exaggerated perceptions of treatment risk amongst primary care physicians that dominate the widespread and accurate knowledge of treatment benefits.

Cardiac Output, Low↗
PubMed1985

Double-beam flying spot scanner for two-dimensional polyacrylamide gel electrophoresis.

The construction of a double-beam photometer in which the light source is a cathode ray oscilloscope is described. The light spot from the oscilloscope was focused and reduced in size at the gel plane to give a diameter of less than 0.15 mm and make it possible to scan over a 50 X 59-mm rectangle; using reduced spatial resolution (spot less than 0.2 mm) the area scanned becomes 70 X 90 mm. The light from the CRT was divided into two beams; one was directed through the transparent object to a photomultiplier and the other to a reference photomultiplier. The signals from these two detectors were converted to the logarithm of the ratio by a logging amplifier to give a direct measure of absorbance. Positioning of the spot, control of light intensity, and measurement of absorbance were carried out through an interface to a 16-bit computer. The relationship between measured and actual absorbance was linear over the range of absorbance 0 to 2, which could be raised to 1 to 3 by placing a neutral filter in the reference beam. The system generated an image containing 256 X 256 pixels in about 5 min, the scanning speed was determined by the persistence time of the P4 phosphor on the cathode ray tube, and faster scans can be made using A6 phosphor.

Calibration↗
PubMed1983

An optical comparator for measuring two-dimensional polyacrylamide gel electrophoresis records using an on-line microcomputer.

A comparator which makes it possible to compare two wet gels or photographic negatives or autoradiograms through a flickering light system has been built. The system consists of two special-purpose projectors which combine the images on a digitizing platform. When the lights are switched On and off out of phase, the positions of the common components remain unchanged, whereas those that are spatially displaced appear to jump from side to side and those present in one image but not the other switch on and off. This produces a flickering image in which differences are readily seen. Commercial camera lenses were used to construct the projectors and the overall specifications for the system are given. The coordinates of both the displaced components, as well as the selected standards from the two images, are digitized and entered automatically into an on-line microcomputer. By using an iterative procedure for collecting records from several superimposable records of the gel, it is possible to compensate for the lack of total reproducibility over the whole gels. These coordinates are then normalized and superimposed on a master map through a television display using a curser to adjust the coordinates. The whole procedure can be repeated for many gels using a common reference gel in the comparator, and the result is a set of normalized coordinates which can be plotted on a single map to provide a final record of the experiments.

Computers↗
PubMed1981

Detection of proteins in human amniotic fluid using two-dimensional gel electrophoresis.

Samples of human amniotic fluid from 48 pregnancies were examined by high resolution two-dimensional gel electrophoresis and the positions of the major peptides were mapped. Many of the proteins in amniotic fluid also occur in adult and fetal serum. Three regions in the amniotic fluid maps could be defined containing peptides which were not found in adult or fetal serum. The concentration of these peptides is variable and their origin is as yet unknown. Many differences were seen between adult and fetal serum proteins.

Adult↗
PubMed1962

WAYS AND MEANS.

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Journal Article↗