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Biomedical subjects

M Dewey

Publications and source records attributed to M Dewey.

At least 37 records · Page 2Linked to original sources
PubMed2001

Identification and expression of cosmids with an allelic variant of class I alcohol dehydrogenase in transgenic mice.

The mouse Adh1 gene exhibits tissue-specific regulation, is developmentally regulated, and is androgen regulated in kidney and adrenal tissue. To study this complex regulation phenotype a transgenic mouse approach has been used to investigate regulatory regions of the gene necessary for proper tissue expression and hormonal control. Transgenic mice have been produced with an Adh1 minigene as a reporter behind either 2.5- or 10 kb of 5'-flanking sequence [1]. Complete androgen regulation in kidney requires a region between -2.5 and -10 kb. A sequence extending to -10 kb does not confer liver expression in this minigene construct. B6.S mice express an electrophoretically variant protein resulting from a known nucleotide substitution resulting in a restriction endonuclease length polymorphism. Transgenic mice harboring B6.S cosmids can be studied for expression analysis at both protein and mRNA levels, identification of transgenic founders and inheritance studies are greatly facilitated by a PCR-restriction endonuclease cleavage approach, the entire mouse gene is used as a reporter, and the formation of heterodimeric enzyme molecules can be used to infer expression of the transgene in the proper cell types within a given tissue. Expression of a B6.S cosmid containing the entire Adh1 gene and 6 kb of 5'- and 21 kb of 3'-flanking region occurs in transgenic mice in a copy number dependent manner in a number of tissues, but expression in liver does not occur. The ability to analyze expression at the protein and mRNA levels has been confirmed using this system. Future directions will involve the use of large BAC clones modified by RARE cleavage to identify the liver specific elements necessary for expression.

Alcohol Dehydrogenase↗
PubMed2001

Coronary magnetic resonance angiography: experimental evaluation of the new rapid clearance blood pool contrast medium P792.

The signal-enhancing characteristics of a new monodisperse monogadolinated macromolecular MR contrast medium (P792) were evaluated for magnetic resonance angiography (MRA) of the coronary arteries. A total of 15 cardiac examinations were performed in pigs at 1.5 T using a 3D gradient-echo sequence. Images were acquired during breath-hold before and up to 35 min after IV injection of Gd-DTPA (0.3 mmol Gd/kg), Gd-BOPTA (0.2 mmol Gd/kg), and P792 (13 micromol Gd/kg). An increase in the signal-to-noise ratio (SNR) of 97% +/- 17%, 108% +/- 37%, and 109% +/- 31% in coronary arteries and of 82% +/- 19%, 82% +/- 24%, and 28% +/- 18% in myocardium, respectively, was measured during the first postcontrast acquisition. The blood-to-myocardium signal-difference-to-noise ratio (SDNR) was significantly higher for P792 than for the other Gd compounds (P <.05) for up to 15 min after injection. Qualitative assessment showed that visualization of the coronary arteries and their branches was significantly better for P792 compared to the low-molecular Gd compounds (P <.05). The blood pool contrast medium P792 is well suited for MRA of the coronary arteries.

Animals↗
PubMed2001

Evaluating a voice recognition system: finding the right product for your department.

The Department of Radiology at the University of Utah Health Sciences Center has been in the process of transitioning from the traditional film-based department to a digital imaging department for the past 2 years. The department is now transitioning from the traditional method of dictating reports (dictation by radiologist to transcription to review and signing by radiologist) to a voice recognition system. The transition to digital operations will not be complete until we have the ability to directly interface the dictation process with the image review process. Voice recognition technology has advanced to the level where it can and should be an integral part of the new way of working in radiology and is an integral part of an efficient digital imaging department. The transition to voice recognition requires the task of identifying the product and the company that will best meet a department's needs. This report introduces the methods we used to evaluate the vendors and the products available as we made our purchasing decision. We discuss our evaluation method and provide a checklist that can be used by other departments to assist with their evaluation process. The criteria used in the evaluation process fall into the following major categories: user operations, technical infrastructure, medical dictionary, system interfaces, service support, cost, and company strength. Conclusions drawn from our evaluation process will be detailed, with the intention being to shorten the process for others as they embark on a similar venture. As more and more organizations investigate the many products and services that are now being offered to enhance the operations of a radiology department, it becomes increasingly important that solid methods are used to most effectively evaluate the new products. This report should help others complete the task of evaluating a voice recognition system and may be adaptable to other products as well.

Humans↗
PubMed2001

Designing fault-tolerant distributed archives for picture archiving and communication systems.

PURPOSE: Distributed archives in a picture archiving and communication system (PACS) environment can provide added fault tolerance and fail-over capability, as well as increased load capacity at a more economical price than traditional 'high-availability" systems. Systems can be configured with varying levels of fault tolerance, depending on the amount of redundancy desired. There is, however, a direct correlation between the level of hardware redundancy and cost to implement. This presentation details the system design for fault-tolerant distributed archives as well as several options for redundancy, referencing implementation of a fault-tolerant archive system at the University of Utah. METHODS: The distributed archive system described here is based on Image Devices' image archive software, which can be implemented on multiple individual archive servers in order to distribute archive functionality and operational load. The configuration and implementation of the individual servers together make up the distributed archive system and does not impact the ability of the system to be scaled to meet future requirements. Several implementation and configuration options exist, including the ability for servers to maintain replicated databases containing patient and image information. Thus, each archive can be aware of all information and the location of this information within the distributed archive system. RESULTS: The goal is to produce systems that will still be operational in the event of any single point of failure, ie, a network connection failure between facilities or the failure of a single archive server within the distributed system. During normal operation, workload for image acquisition, image routing and image query requests will be distributed between the archive servers. If the system is deployed in a multifacility environment, each archive server can be configured to be responsible for the acquisition and image distribution management within that server's local facility. If the system is deployed in a single facility environment, load can be distributed evenly between the archive servers based on an understanding of the workload requirements generated be each acquisition and display device in the system. In the event that an archive server fails, other archive servers within the system will have the ability to provide some or all of the failed server's functionality. The degree of fail-over capability is dependent on the archive server's configuration as well as hardware redundancy employed. Three levels of fault-tolerant design can be achieved with this system architecture: (1) duplicate work capability only; (2) duplicate work capability and short-term image cache; (3) duplicate work capability, short-term image cache, and longterm image archival. Using the basic fault-tolerant design above, we have implemented a multifacility distributed archive system at the University of Utah. This system was implemented at a fraction of the cost of true "high-availability" archive architectures yet provides constant up time for the PACS system. If the network connection between the two locations goes down, each site is still fully functional for soft-copy read, as well as image acquisition and distribution. If either of the archive servers goes down, the image sources are redirected to the other archive server. The operational server then handles image distribution for both locations. Access to images in the short-term image cache is available to both archive servers and is not affected by loss of the network connection or remote server. Because there is ony one long-term archive device, the ability to retrieve images from long-term storage is the only function compromised by a network or server failure. CONCLUSION: By implementing distributed archives in a PACS environment, it is possible to achieve a highly fault-tolerant system without the expense of high-availability hardware and software. The design concepts outlined here can be applied to any PACS system that supports distributed archive functionality.

Computer Systems↗
PubMed2000

Assessing research outcomes by postal questionnaire with telephone follow-up. TOTAL Study Group. Trial of Occupational Therapy and Leisure.

BACKGROUND: Face-to-face assessment of research outcomes is expensive and may introduce bias. Postal questionnaires offer a cheaper alternative which avoids observer bias, but non-response and incomplete response reduce the effective sample size and may be equally serious sources of bias. This study examines the extent and potential effects of missing data in the postal collection of outcomes for a large rehabilitation trial. METHODS: Questionnaires containing a number of established scales were posted to participants in a trial of occupational therapy after stroke. Response was maximized by telephone and postal reminders, and incomplete questionnaires were followed up by telephone. Scale scores obtained by imputing values to questionnaire items missing on return were compared with those achieved by telephone follow-up. FINDINGS: Response to the initial posting was 60%, rising to 85% after reminders. Participants receiving the experimental treatment were more likely to respond without a reminder. There were no significant differences on any known factors between eventual responders and non-responders. Of the questionnaires, 43% were incomplete on return: partial responders were significantly different to complete responders on baseline disability and home circumstances. Of the incomplete questionnaires, 71% were resolved by telephone follow-up. In these, the scale scores achieved by telephone were generally higher than those derived by conventional imputation. CONCLUSION: Postal outcome assessment achieved a good response rate, but considerable effort was needed to minimize non-response and incomplete response, both of which could have been serious sources of bias.

Bias↗
PubMed2000

The effect of home visiting programmes on uptake of childhood immunization: a systematic review and meta-analysis.

BACKGROUND: The aim of the study was to evaluate the effectiveness of home visiting programmes on the uptake of childhood immunization. METHODS: A systematic review was carried out of the literature of controlled studies evaluating home visiting programmes involving at least one post-natal visit, which included tasks within the remit of British health visiting and reporting outcomes relevant to British health visiting. Eleven studies were considered, nine of which used socio-economically disadvantaged families. The outcome measure was uptake of a range of childhood immunizations. RESULTS: Eleven studies reported uptake of immunization. Effect sizes from nine studies were included in the meta-analysis. Fixed effects models demonstrated a significant effect of home visiting for all studies and also for several subgroups of studies, but with significant heterogeneity of effect sizes. A random effects model failed to demonstrate an effect of home visiting. CONCLUSIONS: Home visiting programmes have not been shown to be effective in increasing the uptake of immunization. Other methods of increasing uptake and reducing inequalities in uptake will need to be explored.

Child, Preschool↗
PubMed2000

Does home visiting improve parenting and the quality of the home environment? A systematic review and meta analysis.

AIMS: To evaluate the effectiveness of home visiting programmes on parenting and quality of the home environment. DESIGN: Systematic review of the literature of randomised controlled trials and quasi-experimental studies evaluating home visiting programmes involving at least one postnatal visit. SUBJECTS: Thirty four studies reported relevant outcomes; 26 used participants considered to be at risk of adverse maternal or child health outcomes; two used preterm or low birth weight infants; and two used infants with failure to thrive. Only eight used participants not considered to be at risk of adverse child health outcomes. RESULTS: Seventeen studies reported Home Observation for Measurement of the Environment (HOME) scores, 27 reported other measures of parenting, and 10 reported both types of outcome. Twelve studies were entered into the meta analysis. This showed a significant effect of home visiting on HOME score. Similar results were found after restricting the analyses to randomised controlled trials and to higher quality studies. Twenty one of the 27 studies reporting other measures of parenting found significant treatment effects favouring the home visited group on a range of measures. CONCLUSIONS: Home visiting programmes were associated with an improvement in the quality of the home environment. Few studies used UK health visitors, so caution must be exercised in extrapolating the results to current UK health visiting practice. Further work is needed to evaluate whether UK health visitors can achieve similar results. Comparisons with similar programmes delivered by paraprofessionals or community mothers are also needed.

Child↗
PubMed2000

Assessing effectiveness of treatment of depression in primary care. Partially randomised preference trial.

BACKGROUND: There is a mismatch between the wish of a patient with depression to have counselling and the prescription of antidepressants by the doctor. AIMS: To determine whether counselling is as effective as antidepressants for depression in primary care and whether allowing patients to choose their treatment affects their response. METHOD: A partially randomised preference trial, with patients randomised to either antidepressants or counselling or given their choice of either treatment. The treatment and follow-up were identical in the randomised and patient preference arms. RESULTS: There were 103 randomised and 220 preference patients in the trial. We found: no differences in the baseline characteristics of the randomised and preference groups; that the two treatments were equally effective at 8 weeks, both for the randomised group and when the randomised and patient preference groups for a particular treatment were combined; and that expressing a preference for either treatment conferred no additional benefit on outcome. CONCLUSIONS: These data challenge several assumptions about the most appropriate treatment for depression in a primary care setting.

Adolescent↗
PubMed2000

Treating depression in general practice: factors affecting patients' treatment preferences.

We performed a cross-sectional survey of general practice attenders to determine their preferences regarding treatment for depression and characteristics associated with such preferences. Counselling was more popular than drug therapy (antidepressants), particularly among women, those who believed antidepressants are addictive, and those who had received such treatment in the past.

Adult↗
PubMed1999

Should general practitioners refer patients with major depression to counsellors? A review of current published evidence. Nottingham Counselling and Antidepressants in Primary Care (CAPC) Study Group.

Major depression can be treated effectively with antidepressants. However, in the United Kingdom, patients with depression are often referred to counsellors, and surveys indicate that public opinion favours this approach. We carried out a literature review to determine the evidence for the effectiveness of counselling for depression in primary care. Because no studies were identified in which counselling had been evaluated specifically in relation to treating depression, we examined indirect evidence from studies evaluating the overall effectiveness of generic counselling in primary care, and studies evaluating the effectiveness of psychological treatments, other than counselling, for depression. Methodological problems influencing the interpretation of such studies are discussed. We conclude that, while specific psychological treatments have been shown to have equivalent effectiveness as antidepressants, there is currently insufficient evidence to recommend that generic counselling should be used alone in the treatment of patients with major depression.

Counseling↗
PubMed1997

A nonlinear quasi-static model of intracranial aneurysms.

Biomathematical models of intracranial aneurysms can provide qualitative and quantitative information on stages of aneurysm development through elucidation of biophysical interactions and phenomena. However, most current aneurysm models, based on Laplace's law, are renditions of static, linearly elastic spheres. The primary goal of this study is to: 1. develop a nonlinear constitutive quasi-static model and 2. derive an expression for the critical size/pressure of an aneurysm, with subsequent applications to clinical data. A constitutive model of an aneurysm, based on experimental data of tissue specimens available in the literature, was incorporated into a time-dependent set of equations describing the dynamic behavior of a saccular aneurysm in response to pulsatile blood flow. The set of differential equations was solved numerically, yielding mathematical expressions for aneurysm radius and pressure. This model was applied to clinical data obtained from 24 patients presenting with ruptured aneurysms. Aneurysm development and eventual rupture exhibited an inverse relationship between aneurysm size and blood pressure. In general, the model revealed that rupture becomes highly probable for an aneurysm diameter greater than 2.0 mm and a systemic blood pressure greater than 125 mmHg. However, an interesting observation was that the critical pressure demonstrated a minimal sensitivity to the critical radius, substantiating similar clinical and experimental observations that blood pressure was not correlated, to any degree, with aneurysm rupture. Undulations in the aneurysm wall, presented by irregular multilobulated morphologies, could play an important role in aneurysm rupture. However, due to the large variation in results, more extensive studies will be necessary for further evaluation and validation of this model.

Adult↗
PubMed1996

The development, reliability and validity of a disease specific quality of life model for adults with growth hormone deficiency.

OBJECTIVE: Adults with GH deficiency frequently complain of lack of energy, fatigue, social isolation and problems with sexual relationships resulting in a low perceived quality of life. Previous studies of quality of life (QOL) in GH deficient adults have involved small numbers of patients and used measures not specifically designed for this patient population. We have devised a health related QOL model specifically designed for use in adults with GH deficiency and to assess the impact of future GH replacement therapy. DESIGN: Six measurements were chosen for inclusion in the model. Two were adapted for use after clinical interviews with 12 adult GH deficient patients: the Impact and the Life Fulfilment scales. The others were the Nottingham Health Profile, the Hospital Anxiety and Depression Scale, the Self-Esteem Scale and the Mental Fatigue Questionnaire. The reliability of the 6 measures was assessed by 2 methods: test re-test correlation and internal consistency (Cronbach's alpha). The validity of the Impact and Life Fulfilment scales was assessed by correlation with the other 4 scales. PATIENTS: Questionnaires were completed by 32 adults with hypothalamic pituitary disorders and GH deficiency (11 male, mean age 35.1 years), with a stimulated maximum serum GH response less than 10 mU/l (mean 2.96). Two had previously received GH injections in childhood. The questionnaires were also completed by 32 age and sex matched control subjects. RESULTS: The 6 scales had test re-test correlations of 0.70-0.92 indicating reliability over time. The Impact and Life Fulfilment Scales and the Mental Fatigue Questionnaire had Cronbach's alpha scores of greater than 0.6 indicating their potential for use in clinical trials. The Impact and Life Fulfilment scales correlated significantly with many physical and psychological domains from the other 4 scales indicating these were valid in the assessment of health related QOL in GH deficient adults. Compared to the controls the patients with GH deficiency were significantly psychosocially disadvantaged in terms of depression, self-esteem, mental fatigue and life fulfilment. CONCLUSION: The results of the reliability and validity studies indicate that this health related quality of life model for use with adults with GH deficiency is a potentially valid and reliable tool that could be used to assess the effect of GH treatment.

Activities of Daily Living↗
PubMed1996

A general practice records audit of the process of care for people with epilepsy.

BACKGROUND: The appropriateness of epilepsy as a topic for general practice audit activity has been emphasized, but few audits have been undertaken to data and those that have are small scale. Historically, management of epilepsy has been a neglected area, and services for people with epilepsy remain generally poor. AIM: The study was designed to examine the process of care for people with epilepsy through a region-wide audit of general practitioner records. METHOD: General practitioners in 31 randomly selected general practices in one UK health region undertook a notes audit for all patients identified as having active epilepsy (patients who had had seizures in the last 2 years, or were currently seizure-free but on antiepileptic medication). A standard pro forma was used to collect information relating to diagnosis, drug treatment, and primary and secondary care contacts. RESULTS: Recording of information in the notes was generally good, but poor for some key items essential to the effective management of the condition; results suggest that a number of recommendations about provision of care for epilepsy are not being met: in particular, EEG and CT investigations often appear poorly directed; prescribed antiepileptic therapy is not always optimal; significant numbers of patients are being treated in hospital by non-neurologists; there is little evidence of any regular review being undertaken by general practitioners of their patients with epilepsy; and counselling about the non-clinical aspects of epilepsy often appears inadequate. CONCLUSIONS: Despite recommendations in a number of recent reports, gaps and inconsistencies in epilepsy care persist, both at the primary and secondary level. The means by which such shortcomings can be reduced (e.g. by specialist epilepsy nurses working across the primary-secondary care interface) should now be systematically examined. The study has highlighted a need for evidence-based guidelines which span the primary-secondary care interface and clarify the contribution of the various practitioners involved in the provision of care for people with epilepsy.

Adolescent↗
PubMed1995

A self-rating scale for measuring neuroleptic side-effects. Validation in a group of schizophrenic patients.

BACKGROUND: A study was conducted to validate a comprehensive self-rating scale for measuring side-effects of neuroleptic drugs. METHOD: The Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS), which includes 'red herring' items, was twice administered to 50 DSM-III-R schizophrenic patients, who were also interviewed using the UKU side-effect rating scale; 50 unmedicated controls also completed the LUNSERS: RESULTS: The test-retest reliability of the LUNSERS was good (r = 0.811, P < 0.001) as was its concurrent validity against the UKU (r = 0.828, P < 0.001). Scores correlated with chlorpromazine equivalent doses (r = 0.310, P < 0.02). ROC analysis demonstrated that the scale discriminated between patients and non-medicated controls, who scored differently for real side-effects but not for 'red herring' items. CONCLUSIONS: The LUNSERS is an efficient, reliable and valid method of assessing neuroleptic side-effects.

Adult↗
PubMed1995

The Windsor Clinic Alcohol Withdrawal Assessment Scale (WCAWAS): investigation of factors associated with complicated withdrawals.

A new scale for measuring the severity of the alcohol withdrawal syndrome has been developed. The Windsor Clinic Alcohol Withdrawal Assessment Scale (WCAWAS) has more objective criteria than its parent scales and has high inter-rater reliability and concurrent validity. This article describes the development of the WCAWAS and its use in an investigation of which factors were associated with complicated withdrawals in 142 consecutive patients admitted for detoxification. Multivariate analyses showed that drinking behaviour variables and MCV were successful at predicting complicated withdrawals. The WCAWAS was not successful at predicting which patients developed convulsions. Further studies are required to see if the WCAWAS is more successful at predicting which patients will develop visual hallucinations. The WCAWAS is useful as a teaching aid and in following the clinical course of patients and their response to treatment.

Adult↗
PubMed1994

Stress in midwifery: a comparison of midwives and nurses using the Work Environment Scale.

Previous research into midwifery has identified a number of potential sources of stress without attempting to understand the variables that might contribute to it. The study sample was drawn from a population of registered nurses and midwives and compares the work environment of 29 midwives with 180 nurses, using the Work Environment Scale Questionnaire. Significant differences were found between midwives and nurses for involvement, supervisor support, autonomy, work pressure and clarity of roles. These results have the potential for forming the basis of future research.

Analysis of Variance↗