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Biomedical subjects

P Prescott

Publications and source records attributed to P Prescott.

At least 19 recordsLinked to original sources
PubMed2007

Determination of suitable sample sizes for multi-patient based finite element studies.

Finite element analysis is used extensively to assess joint replacements, but the majority of these are single sample studies. Recent investigations have suggested that such studies are unable to account for natural inter-patient variation in bone geometry and material property distribution. Recent developments in computer tomography based analyses make multiple sample studies possible; the question remains how many femurs are required to perform a study which accounts for such variations. This work investigates the factors that should be considered in answering this question. It explores sample sizing techniques when comparing strain distribution in the intact and implanted femur and when comparing two or more implant designs in a group of femurs. An example analysis of the effect of femoral head resurfacing was undertaken. Two sample sizing calculations were utilised, one based on achieving the desired precision in results, the other based on determining if a significant difference exists between two designs. The analysis shows that reasonable statistical precision can be achieved with a group of femurs. The study was also able to determine a suitable sample size for the analysis of a statistically significant difference between two groups of femurs with varying design parameters. The study concluded that while sample sizing is recommended for an accurate analysis, consideration must be made for the practicality of such a task.

Biomechanical Phenomena↗
PubMed2006

Bromelain as an adjunctive treatment for moderate-to-severe osteoarthritis of the knee: a randomized placebo-controlled pilot study.

BACKGROUND: Osteoarthritis (OA) of the knee is the most prevalent joint disorder. Previous studies suggest that bromelain, a pineapple extract, may be a safer alternative/adjunctive treatment for knee OA than current conventional treatment. AIM: To assess the efficacy of bromelain in treating OA of the knee. DESIGN: Randomized, double-blind placebo-controlled trial. METHODS: Subjects (n = 47) with a confirmed diagnosis of moderate to severe knee OA were randomized to 12 weeks of bromelain 800 mg/day or placebo, with a 4-week follow-up. Knee (pain, stiffness and function) and quality-of-life symptoms were reported monthly in the WOMAC and SF36 questionnaires, respectively. Adverse events were also recorded. The primary outcome measure was the change in total WOMAC score from baseline to the end of treatment at week 12. Longitudinal models were used to evaluate outcome. RESULTS: Thirty-one patients completed the trial (14 bromelain, 17 placebo). No statistically significant differences were observed between groups for the primary outcome (coefficient 11.16, p = 0.27, 95%CI -8.86 to 31.18), nor the WOMAC subscales or SF36. Both treatment groups showed clinically relevant improvement in the WOMAC disability subscale only. Adverse events were generally mild in nature. DISCUSSION: This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA, but its limitations support the need for a follow-up study.

Aged↗
PubMed2004

How do homeopaths make decisions? An exploratory study of inter-rater reliability and intuition in the decision making process.

The validity of clinical decision making in homeopathy is largely unexplored and little is understood about the process or its reliability. This exploratory study investigated, in the context of a questionnaire based re-proving of Belladonna 30c, the extent to which decisions are based on clinical facts or intuition and how reliable decisions are. Three experienced, independent homeopathic clinicians/proving researchers rated the symptom diaries of the 206 subjects taking part. They reported their proving decision (ie positive proving response, no proving response or undecided) based on the total symptom profiles and rated (on a scale of 0-10) their use of clinical facts or intuition. Keynote symptoms and overall confidence scores were also reported. The level of agreement between raters was generally poor (weighted kappa 0.349-0.064). All raters used both facts and intuition. The rater's reliance on the facts was significantly associated with classifying those subjects who had no proving response [rater 1, P<0.001; rater 2, P<0.001]. Raters used significantly higher intuition scores when classifying a prover [rater 2, P= 0.001; rater 3, P= 0.012]. Issues regarding the education and practice of homeopathy are discussed.

Adult↗
PubMed2002

Risperidone in chronic schizophrenia: a detailed audit, open switch study and two-year follow-up of patients on depot medication.

Little information exists on the medium- to long-term outcome of switching patients with schizophrenia from traditional depot to atypical oral antipsychotic agents. By detailed clinical audit, we identified a representative group of 102 patients of an Irish psychiatric service with DSM-IV chronic schizophrenia and on depot neuroleptics for a mean of 15 years. Of 69 eligible to participate, 33 entered a 6-month switch study of risperidone, with limited follow-up of consenters and non-consenters at 1 and 2 years. At 6 months, 23 of 33 were still on risperidone and had small significant improvements in clinical and extrapyramidal side effects, QOL and adjunct medication measures over baseline. At 12 months, 19 of 33 were still on risperidone, reducing to 13 of 33 at 2 years. At 2 years, of 32 surviving consenters to switch, 19 had suffered clinically detrimental events and were no longer on risperidone, compared to none of the 33 surviving non-consenters, who were all still on depot. These findings suggest that switching from depot to risperidone may encounter high rates of refusal and attrition subsequent to switch. While a majority of switched patients may improve to least 6 months, audit plus switch may have clinically unfavourable effects on others over a 2-year follow-up period [corrected].

Adolescent↗
PubMed2002

Complementary cancer care in Southampton: a survey of staff and patients.

BACKGROUND: Complementary and alternative medicine (CAM) is used by one in ten of the UK population yearly and 47% during their lifetime. One-third of cancer patients seek some form of CAM treatment during their illness. AIM: To evaluate the use of and attitudes to CAM among patients and all healthcare staff in the Southampton Cancer Care Directorate (UK). SETTING: The Royal South Hants Hospital, Countess Mountbatten and Oakhaven Hospices. METHOD: A questionnaire-based survey performed between January 2001 and March 2001. RESULTS: Two hundred and seventy questionnaires were distributed to patients and 162 responses received. The distribution of cancers within this population was generally typical of those in the community. Thirty-two percent (n = 52) were receiving some form of CAM, half of those receiving CAM were in hospice care. Forty-nine percent of those not receiving CAM would like to, and 76% of all patients would be prepared to pay for this treatment. The five most popular treatments were massage, nutrition, aromatherapy, relaxation and reflexology. While most patients expected CAM to palliate their symptoms (n = 149, 92%), some had unrealistic expectations that CAM would cure their cancer (n = 13, 8%). Four hundred and forty-eight staff questionnaires were distributed and 196 responses were received: 148 (75.5%) from nurses. Twenty-one percent of staff responding had CAM training and two-thirds would like to receive training. The most popular therapies used by staff were the same as those identified by the patients. Ninety-nine percent of staff and 98.5% of patients wished to see CAM treatments introduced into service provision within the Cancer Care Directorate. CONCLUSIONS: The use of CAM for cancer care in Southampton is widespread and consistent with its use nationally. There is a clearly expressed need for CAM treatments by patients and a willingness to pay. Two-thirds of the cancer care staff responding wished to receive training in and provide these therapies. There are some misconceptions among patients about the role of CAM in cancer care which need to be discussed and resolved. We believe that all cancer care units should have clear policies on the use of CAM for cancer patients.

Adolescent↗
PubMed2001

Is electrodermal testing as effective as skin prick tests for diagnosing allergies? A double blind, randomised block design study.

OBJECTIVE: To evaluate whether electrodermal testing for environmental allergies can distinguish between volunteers who had previously reacted positively on skin prick tests for allergy to house dust mite or cat dander and volunteers who had reacted negatively to both allergens. DESIGN: Double blind, randomised block design. SETTING: A general practice in southern England. PARTICIPANTS: 15 volunteers who had a positive result and 15 volunteers who had a negative result on a previous skin prick test for allergy to house dust mite or cat dander. INTERVENTION: Each participant was tested with 6 items by each of 3 operators of the Vegatest electrodermal testing device in 3 separate sessions (a total of 54 tests per participant). For each participant the 54 items comprised 18 samples each of house dust mite, cat dander, and distilled water, though these were randomly allocated among the operators in each session. A research nurse sat with the participant and operator in all sessions to ensure blinding and adherence to the protocol and to record the outcome of each test. OUTCOME: The presence or absence of an allergy according to the standard protocol for electrodermal testing. RESULTS: All the non-atopic participants completed all 3 testing sessions (810 individual tests); 774 (95.5%) of the individual tests conducted on the atopic participants complied with the testing protocol. The results of the electrodermal tests did not correlate with those of the skin prick tests. Electrodermal testing could not distinguish between atopic and non-atopic participants. No operator of the Vegatest device was better than any other, and no single participant's atopic status was consistently correctly diagnosed. CONCLUSION: Electrodermal testing cannot be used to diagnose environmental allergies.

Adult↗
PubMed2001

A pilot project to assess the methodological issues involved in evaluating acupuncture as a treatment for disabling breathlessness.

OBJECTIVES: This pilot study explores the methodological implications of evaluating the use of acupuncture in the treatment of disabling breathlessness. DESIGN: A randomized, controlled trial involving three treatments that were used on one occasion, each in random order. SETTINGS: The study was designed to evaluate the feasibility of providing acupuncture treatment on a domiciliary basis, in Southampton (United Kingdom) to patients with disabling breathlessness. SUBJECTS: Sixteen (16) subjects with disabling breathlessness caused by chronic lung disease (primarily chronic obstructive pulmonary disease [COPD]) were recruited from the respiratory medicine clinics of Southampton University Hospitals Trust. INTERVENTIONS: The treatments were real acupuncture, dummy acupuncture, and mock transelectrical nerve stimulation (TENS). OUTCOMES: To evaluate the respiratory outcome measures, to look at the credibility of the three treatments (using a previously validated Borkovec and Nau scale), and to calculate the sample size for a larger, more definitive study. RESULTS: Twelve (12) subjects completed the study. The acupuncture was a predefined point prescription that had been found previously to be of value in this condition, an approach that could be taught to health professionals and provided on a domiciliary basis. The treatment was provided only on one occasion, therefore, we did not expect a clear therapeutic benefit to emerge, but some nonsignificant benefit was noted as a consequence of acupuncture treatment. The shuttle test that we used as an objective measure of breathlessness was impractical in a domiciliary environment and will not be used in further studies. Each of the three treatments was equally credible at the outset, although real and dummy acupuncture were considered by the patients to be preferable choices after the completion of treatment. CONCLUSIONS: It was possible to carry out this study on a domiciliary basis. The information obtained will allow us to design a much clearer definitive study and the small, but statistically insignificant, response to acupuncture has allowed us to estimate sample size.

Acupuncture Therapy↗
PubMed2001

Chronic intermittent intravenous insulin therapy: a new frontier in diabetes therapy.

The limited success achieved in controlling diabetes and its complications with conventional insulin therapy suggests the need for reevaluation of the appropriateness of insulin administration protocols. Indeed, conventional subcutaneous insulin administration produces slowly changing blood insulin levels and suboptimal hepatocyte insulinization resulting in impaired hepatic capacity for processing incoming dietary glucose. The novel approach to insulin administration known as chronic intermittent intravenous insulin therapy (CIIIT) delivers insulin in a pulsatile fashion and achieves physiological insulin concentration in the portal vein. Done as a weekly outpatient procedure combined with daily intensive subcutaneous insulin therapy, this procedure has been shown to (1) significantly improve glycemic control while decreasing the incidence of hypoglycemic events, (2) improve hypertension control, (3) slow the progression of overt diabetic nephropathy, and (4) reverse some manifestations of diabetic autonomic neuropathy (e.g., abnormal circadian blood pressure pattern, severe postural hypotension, and hypoglycemia unawareness).

Biomarkers↗
PubMed1999

Construction of uniform-balanced cross-over designs for any odd number of treatments.

Cross-over designs balanced for simple carry-over effects are commonly applied in clinical studies for the comparison of treatments for chronic conditions such as hypertension or asthma. Uniform-balanced cross-over designs have the desirable property that the treatment sequences are arranged so that, in the full design, each treatment is followed by every other treatment equally often. Such designs for an even number of treatments and the same number of sequences and periods are readily constructed using suitable cyclic Latin squares. For an odd number of treatments, pairs of squares may be combined to give uniform-balanced designs. Recently, computer search techniques have been used to find nearly-balanced Latin squares which may be combined in pairs or in sets of three to produce designs with the overall properties of uniformity and balance. In this paper, simple generating formulae are described which will give, for any odd number of treatments t > 3, uniform-balanced cross-over designs with p = t periods and n = kt treatment sequences for any k > or = 2. Tables of cross-over designs obtained from these simple formulae are presented for t < or = 15.

Biometry↗
PubMed1999

Pathogenesis of fibrosing colonopathy: the role of methacrylic acid copolymer.

Fibrosing colonopathy is a serious bowel disorder which was first seen in 1991 in patients with cystic fibrosis treated with high doses of pancreatic enzyme supplements. Epidemiological evidence from two case-control studies, temporal data and direct experimental evidence support the conclusion that there is a causal relationship between the disease and intake of high doses of the excipient, methacrylic acid copolymer, which is used to coat certain brands of pancreatic enzyme. A high intake of lipase, the active ingredient in pancreatic enzymes, is not a risk factor for fibrosing colonopathy in the absence of methacrylic acid copolymer. Excipients may be toxic if used in new patient populations such as children and in doses exceeding the safe levels predicted by animal toxicology.

Journal Article↗
PubMed1997

Patterns of use of pancreatic enzyme supplements in fibrosing colonopathy: implications for pathogenesis.

Sixteen pathologically confirmed and 14 suspected cases of a new disease entity, fibrosing colonopathy, have been described in the UK and the US in children with cystic fibrosis since 1991. The patterns of use of pancreatic enzyme supplements in cases were compared with use in controls and in the market, in the 2 years prior to surgery for fibrosing colonopathy or the equivalent date in controls. The disease was only found in children with cystic fibrosis who had received brands of pancreatic enzyme supplement coated with methacrylic acid copolymer, for a period of at least 6 months. The risk was dose-related. No cases could be identified in children who had only received other pancreatic enzyme formulations, irrespective of the strength of the formulation or the dose.

Journal Article↗
PubMed1996

Testing for adverse reactions using prescription event monitoring.

The Drug Safety Research Unit's current methods of investigating adverse drug reactions using prescription event monitoring are discussed. The statistical properties of estimators of rates of occurrence of events in post-marketing surveillance using prescription event monitoring are considered, and a simple model is proposed based on an exponential distribution of time to first occurrence of the event. It is shown that current methodology closely relates to the use of maximum likelihood estimation under this assumption and the distributions of the estimators are shown to be approximately normal, which allows simple confidence intervals and tests to be developed. Two recent applications are considered and corresponding simulations are presented to verify the approximate properties of the test statistics, based on ratios of rates over time and between drugs. Sources of bias in the rates and rate ratios are considered, including under-reporting in later months. A rule-of-thumb, developed from many years experience, is shown to be generally conservative, except when these under-reporting biases are large.

Adverse Drug Reaction Reporting Systems↗
PubMed1996

The Galway Study of Panic Disorder. III. Outcome at 5 to 6 years.

BACKGROUND: The aim was to evaluate long-term outcome of DSM-III-R panic disorder at a mean of 5.3 years following a controlled trial of treatment that included antidepressants and behavioural counselling. METHOD: Sixty-eight (86%) subjects were evaluated by lengthy research interview. RESULTS: Thirty-four per cent recovered and remained well, 46% were minimally impaired and 20% had persistent panic disorder of whom half remained significantly impaired. Anxious-fearful personality dysfunction was the most important predictor of poor outcome, followed by poor clinical status at discharge and inability at baseline to recall vividly the initial panic attack. Those who dropped out from the original trial did badly. CONCLUSIONS: Complete recovery can occur even after many years of severe illness in a large minority of subjects who receive both antidepressants and behavioural counselling in the acute stage of treatment. The comparative prognostic value of personality, severity and chronicity need to be more fully addressed in future studies.

Adult↗
PubMed1996

The Galway Study of Panic Disorder. IV. Temporal stability of diagnosis by present state examination test-retest.

BACKGROUND: A long-term outcome study of DSM-III-R panic disorder included the Present State Examination (PSE) at baseline and follow up five to six years later. METHOD: PSE test-retest and individual within-patient change scores on various PSE syndromes were assessed for consistency with either a categorical view of panic disorder as a stable clinical entity or panic disorder as one facet only of a "general neurotic syndrome'. RESULTS: PSE profile at baseline was virtually identical with that at follow up. Few patients had changed in PSE syndrome diagnosis after five to six years. CONCLUSION: These data, although not conclusive, are supportive of the concept of DSM-III-R panic disorder as a stable clinical entity and are correspondingly difficult to reconcile with the view that panic disorder is but one facet only of a general neurotic syndrome.

Antidepressive Agents, Tricyclic↗
PubMed1995

Neural network prediction of nonstress test results: how often should we perform nonstress tests?

OBJECTIVE: Our purpose was to predict outcomes and optimal intervals for nonstress tests of term gravid women with neural networks. STUDY DESIGN: We studied 100 normal term patients whose 30-minute nonstress tests, performed on 5 consecutive days, were computer analyzed for the following elements: fetal heart rate baseline, variability, signal loss, accelerations (> 15 beats/min), and decelerations. The training set used 65 patients; the testing, 35 patients. Nonstress test data (days 1 to 4) were inputs; day 5 data were training patterns. Networks for each nonstress test element used Brainmaker Macintosh 1.0 (California Scientific Software, Nevada City, Calif.) trained to 0.12 tolerance. Actual fetal heart rate elements and their daily differences were compared with predictions by the networks and multiple regressions. RESULTS: There was little difference between networks using daily or alternate-day inputs for predicting test performance on day 5; networks using test intervals > 2 days could not be trained to tolerance. Long-term fetal heart rate variation was the nonstress test element best predicted. Daily differences networks provided better prediction of all day 5 data than did actual daily values networks or multiple regression formulas. CONCLUSIONS: Baseline long-term fetal heart rate variability seems to be the most predictable fetal heart rate element over time and should merit more consideration in overall fetal testing. Fetal heart rate elements are not easily predicted by any method for intervals longer than 2 days. Using longer test intervals might run a greater risk for unanticipated changes in nonstress test outcomes, even when fetal condition is normal.

Female↗
PubMed1995

Signalling drug-induced rash with 36 drugs recently marketed in the United Kingdom and studied by Prescription-Event Monitoring.

This study examines skin rash, as a reported event, in the patients who used one of the 36 drugs recently released to the UK market and studied by Prescription-Event Monitoring between 1985 and 1992. The results are also compared to the voluntary reports on rash as a possible adverse drug reaction sent to the Committee on Safety of Medicines (CSM). Specific types of skin rash (e.g. exfoliative dermatitis) are excluded. The rate of rash has been calculated for 2 periods, the first month (T1) and the subsequent 5 months (T2) after the first prescription for the drug. Despite the heterogeneity of the patient groups, the rate for rash between the 2nd and 6th months was consistent in the 36 drugs and probably represented the baseline rate of rash due to a variety of nonspecific causes. This rate (T2) was around 1 per 1,000 patients per month (ranging from 0.5 to 2 per 1,000 patients per month). On the other hand, in the first month after the first prescription for the drug, the rate (T1) varied substantially from 0.9 to 6.4 per 1,000 patients per month. Diltiazem had the highest first monthly rate. These rates are listed for the 36 drugs. The difference of the rates was tested by 2 methods: a standard statistical test assuming a Poisson model and a method based on the ratio of the rates for the 2 periods. When the 2 rates (T1 and T2) were similar to each other, drug induced rash was considered to be rare.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗