90 research outputs found

    A Study of Non-steroidal Anti-inflammatory Drugs in the Urine of the Racing Greyhound

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    The purpose of this study was to develop a screening procedure for the detection of non-steroidal anti-inflammatory drugs (NSAIDs) in the urine of the racing greyhound. The study was divided into three parts, dealing with the evaluation and selection of an appropriate analytical methodology, the investigation of acidic endogenous components of greyhound urine and the analysis of selected NSAIDs in urine following administration at therapeutic levels to greyhounds. (1) in the first part of the study, the analytical methods examined were isocratic high pressure liquid chromatography (HPLC) with ultraviolet (UV) detection, capillary gas chromatography (GC) with temperature programming and flame ionisation detection and gas chromatography-mass spectrometry (GC-MS). Twelve NSAIDs in common use in the UK were selected as test compounds for the evaluation of the separating ability, selectivity and sensitivity of detection of the three methods. (a) HPLC : For one compound, phenylbutazone, the HPLC capacity factor (k' ) was measured in seven reversed-phase solvent systems using an octadecylsilane column. The remaining compounds were examined on two selected systems. In addition, fluorescence spectrometry and electrochemical detection (ECD) were examined to assess their value as additional HPLC detection systems which might increase the selectivity or sensitivity of the method. All of the test compounds were eluted from the column and could be detected by UV spectrometry at a sample size of 5 nanograms on-column. Five of the test compounds could be detected by fluorescence spectrometry and seven by ECD. However, none of the solvent systems examined resolved all of the test compounds from each other. (b) GLC: Three chemical derivatives were evaluated to increase the thermal stability and improve the chromatographic behaviour of the test compounds - the methyl, trimethylsilyl and tertiary-butyldimethylsilyl derivatives. The retention indices of the three derivatives for each substance were recorded using a glass capillary column coated with dimethylsilicone (non-polar) stationary phase. Three compounds, all pyrazolidine diones, could be chromatographed without derivatisation but produced a mixture of products following reaction with the methylating agent, diazomethane. These were further examined by mass spectrometry. (c) GC-MS : Gas chromatography with mass spectrometric detection was carried out using similar GC conditions to those described above. Electron impact spectra were recorded at 70 ev for each of the derivatives of the test substances and possible fragmentation reactions giving rise to the most prominent ions in the spectra were proposed. The reaction products of pyrazolidinedione NSAIDs produced by reaction with diazomethane were characterised by GC-MS and tentative structures were proposed in which methylene addition had occurred at the enol-oxygen atom and at the carbonyl group, to give enol ethers and oxiranes respectively. It was concluded that GC-MS was the only method which would have sufficient selectivity and separating ability for use in a screening procedure and this method was used in the rest of the study. (2) The second part of the study established the normal pattern of organic acids present in greyhound urine, which would be co-extracted with any NSAIDs present and might lead to interference in the detection and quantitation of the drugs. (3) In the third part of the study five test compounds (ibuprofen, naproxen, ketoprofen, mefenamic acid and phenylbutazone) were administered at therapeutic levels to greyhounds. Blood and urine samples were collected serially in the ibuprofen and mefenamic acid experiments. Urine samples only were collected for the remaining three compounds. urinary creatinine concentrations were measured for each sample. The urinary components were extracted as before with XAD-2 resin and glucuronide and sulphate conjugates present in the samples were hydrolysed by incubation with helix-pomatia extract. Plasma samples were extracted using heptane:ethyl acetate. All samples were methylated using diazomethane. The five test compounds were detected and quantified in the urine and plasma samples collected. Plasma drug concentration/time curves and excretion profiles were obtained for ibuprofen and mefenamic acid. Metabolites of ibuprofen and naproxen were observed in urine samples. The importance of parallel creatinine measurements to correct for variation in the urinary volume was shown in the naproxen study. The implications of the results with respect to the detection of these five drugs and the interpretation of their concentrations during a screening procedure at a race meeting are discussed

    Librarian Class Attendance: Blogs, statistics, outcomes and opportunities.

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    What, if any, are the benefits of having librarians attend lectures and seminars? In the midst of a start-up program, the librarians at the Weill Cornell Medical College in Qatar were challenged to test new models of active participation while demonstrating positive outcomes. This paper describes the setting, methods, and outcomes associated with having librarians attend courses as active members in an evolving learning environment. Interactions with faculty and students will be analyzed to assess whether course attendance benefits professional relationships in a way that positively impacts student learning. In parallel, an examination of assessment measures for determining value of service will also be undertaken

    A comparison of hospital readmission rates between two general physicians with different outpatient review practices

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    BACKGROUND: There has been a relentless increase in emergency medical admissions in the UK over recent years. Many of these patients suffer with chronic conditions requiring continuing medical attention. We wished to determine whether conventional outpatient clinic follow up after discharge has any impact on the rate of readmission to hospital. METHODS: Two consultant general physicians with the same patient case-mix but markedly different outpatient follow-up practice were chosen. Of 1203 patients discharged, one consultant saw twice as many patients in the follow-up clinic than the other (Dr A 9.8% v Dr B 19.6%). The readmission rate in the twelve months following discharge was compared in a retrospective analysis of hospital activity data. Due to the specialisation of the admitting system, patients mainly had cardiovascular or cerebrovascular disease or had taken an overdose. Few had respiratory or infectious diseases. Outpatient follow-up was focussed on patients with cardiac disease. RESULTS: Risk of readmission increased significantly with age and length of stay of the original episode and was less for digestive system and musculo-skeletal disorders. 28.7% of patients discharged by Dr A and 31.5 % of those discharged by Dr B were readmitted at least once. Relative readmission risk was not significantly different between the consultants and there was no difference in the length of stay of readmissions. CONCLUSIONS: Increasing the proportion of patients with this age- and case-mix who are followed up in a hospital general medical outpatient clinic is unlikely to reduce the demand for acute hospital beds

    Relationship between blood pressure measurements recorded on patients' charts in family physicians' offices and subsequent 24 hour ambulatory blood pressure monitoring

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    BACKGROUND: In most western countries 20% of adults have hypertension. Reports in the literature suggest that from 31 to 86% of treated patients are not at recommended target levels. However it is important to consider how we are determining whether targets are unmet and the degree to which they are unmet. Our underlying hypothesis is that white coat effect is partially responsible for the reported low rates of control of hypertension by primary care practitioners. METHODS: The study population consists of 1142 patients who are being assessed for enrolment in two community-based randomized controlled trials. Patients must have essential hypertension, be on antihypertensive medication, and must not have met their blood pressure targets. We are reporting on the proportion of patients who have not achieved target, and the degree to which they have not achieved their target. We also report on the mean daytime blood pressures on 24 hour ABPM and compare these to mean blood pressures found on the patients' charts. RESULTS: We identified 3284 patient charts of patients with hypertension. Of these, 1142 were determined to be "out of control" (did not achieve target) and 436 agreed to undergo 24 hour ABPM for final determination of eligibility. Overwhelmingly (95.8% of the time) it was the systolic blood pressure that was not under control. However, most of the patients who had not achieved target according to our criteria were within 10 mmHg of the recommended targets. Isolated systolic blood pressure was the best predictor of elevated mean daytime blood pressure on 24 hour ABPM. CONCLUSIONS: At least 35% of patients had not achieved target blood pressure levels and this is primarily due to lack of control of systolic blood pressure. The best predictor of continuing hypertension on 24 hour ABPM was the mean systolic blood pressure on the patients chart. However, only 69% of patients who were uncontrolled according blood pressures recorded in the chart were uncontrolled according to 24 hour ABPM criteria. This suggests that the white coat effect makes blood pressure measurements in the doctor's offices, at least as currently done, not sufficiently accurate for determining treatment endpoint

    Pragmatic controlled clinical trials in primary care: the struggle between external and internal validity

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    BACKGROUND: Controlled clinical trials of health care interventions are either explanatory or pragmatic. Explanatory trials test whether an intervention is efficacious; that is, whether it can have a beneficial effect in an ideal situation. Pragmatic trials measure effectiveness; they measure the degree of beneficial effect in real clinical practice. In pragmatic trials, a balance between external validity (generalizability of the results) and internal validity (reliability or accuracy of the results) needs to be achieved. The explanatory trial seeks to maximize the internal validity by assuring rigorous control of all variables other than the intervention. The pragmatic trial seeks to maximize external validity to ensure that the results can be generalized. However the danger of pragmatic trials is that internal validity may be overly compromised in the effort to ensure generalizability. We are conducting two pragmatic randomized controlled trials on interventions in the management of hypertension in primary care. We describe the design of the trials and the steps taken to deal with the competing demands of external and internal validity. DISCUSSION: External validity is maximized by having few exclusion criteria and by allowing flexibility in the interpretation of the intervention and in management decisions. Internal validity is maximized by decreasing contamination bias through cluster randomization, and decreasing observer and assessment bias, in these non-blinded trials, through baseline data collection prior to randomization, automating the outcomes assessment with 24 hour ambulatory blood pressure monitors, and blinding the data analysis. SUMMARY: Clinical trials conducted in community practices present investigators with difficult methodological choices related to maintaining a balance between internal validity (reliability of the results) and external validity (generalizability). The attempt to achieve methodological purity can result in clinically meaningless results, while attempting to achieve full generalizability can result in invalid and unreliable results. Achieving a creative tension between the two is crucial

    Ambulatory teaching: Do approaches to learning predict the site and preceptor characteristics valued by clerks and residents in the ambulatory setting?

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    BACKGROUND: In a study to determine the site and preceptor characteristics most valued by clerks and residents in the ambulatory setting we wished to confirm whether these would support effective learning. The deep approach to learning is thought to be more effective for learning than surface approaches. In this study we determined how the approaches to learning of clerks and residents predicted the valued site and preceptor characteristics in the ambulatory setting. METHODS: Postal survey of all medical residents and clerks in training in Ontario determining the site and preceptor characteristics most valued in the ambulatory setting. Participants also completed the Workplace Learning questionnaire that includes 3 approaches to learning scales and 3 workplace climate scales. Multiple regression analysis was used to predict the preferred site and preceptor characteristics as the dependent variables by the average scores of the approaches to learning and perception of workplace climate scales as the independent variables. RESULTS: There were 1642 respondents, yielding a 47.3% response rate. Factor analysis revealed 7 preceptor characteristics and 6 site characteristics valued in the ambulatory setting. The Deep approach to learning scale predicted all of the learners' preferred preceptor characteristics (β = 0.076 to β = 0.234, p < .001). Valuing preceptor Direction was more strongly associated with the Surface Rational approach (β = .252, p < .001) and with the Surface Disorganized approach to learning (β = .154, p < 001) than with the Deep approach. The Deep approach to learning scale predicted valued site characteristics of Office Management, Patient Logistics, Objectives and Preceptor Interaction (p < .001). The Surface Rational approach to learning predicted valuing Learning Resources and Clinic Set-up (β = .09, p = .001; β = .197, p < .001). The Surface Disorganized approach to learning weakly negatively predicted Patient Logistics (β = -.082, p = .003) and positively the Learning Resources (β = .088, p = .003). Climate factors were not strongly predictive for any studied characteristics. Role Modeling and Patient Logistics were predicted by Supportive Receptive climate (β = .135, p < .001, β = .118, p < .001). CONCLUSION: Most site and preceptor characteristics valued by clerks and residents were predicted by their Deep approach to learning scores. Some characteristics reflecting the need for good organization and clear direction are predicted by learners' scores on less effective approaches to learning

    The incidence of HIV among women recruited during late pregnancy and followed up for six years after childbirth in Zimbabwe

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    <p>Abstract</p> <p>Background</p> <p>HIV incidence is a useful tool for improving the targeting of populations for interventions and assessing the effectiveness of prevention strategies. A study in Harare, Zimbabwe reported cumulative incidences of 3.4% (3.0-3.8) and 6.5% (5.7-7.4) among post-partum women followed for 12 and 24 months respectively between 1997 and 2001. According to a Government report on HIV the prevalence of HIV fell from about 30% in 1999 to 14% in 2008. The purpose of this study was to determine the incidence of HIV-1 among women enrolled during late pregnancy and followed for six years after childbirth and to identify risk factors associated with acquisition of HIV.</p> <p>Methods</p> <p>HIV-uninfected pregnant women around 36 weeks gestation were enrolled from primary health care clinics in peri-urban settlements around Harare and followed-up for up to six years after childbirth. At every visit a questionnaire was interview-administered to obtain socio-demographic data and sexual history since the previous visit. A genital examination was performed followed by the collection of biological samples.</p> <p>Results</p> <p>Of the 552 HIV-uninfected women 444 (80.4%) were seen at least twice during the six years follow-up and 39 acquired HIV, resulting in an incidence (95% CI) of 2.3/100 woman-years-at-risk (wyar) (1.1-4.1). The incidence over the first nine months post-partum was 5.7/100 wyar (3.3-8.1). A greater proportion of teenagers (15.3%) contributed to a high incidence rate of 2.9/100 (0.6-8.7) wyar. In multivariate analysis lower education of participant, RR 2.1 (1.1-4.3) remained significantly associated with HIV acquisition. Other risk factors associated with acquisition of HIV-1 in univariate analysis were young age at sexual debut, RR 2.3, (1.0-5.6) and having children with different fathers, RR 2.7(1.3-5.8). Women that knew that their partners had other sexual partners were about four times more likely to acquire HIV, RR 3.8 (1.3-11.2).</p> <p>Conclusion</p> <p>The incidence of HIV was high during the first nine months after childbirth. Time of seroconversion, age and educational level of seroconverter are important factors that must be considered when designing HIV intervention strategies.</p

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
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