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Biomedical subjects

A Davie

Publications and source records attributed to A Davie.

16 recordsLinked to original sources
PubMed2006

A comparative ex vivo and in vivo study of day and night perception in teleosts species using the melatonin rhythm.

The purpose of this study was to determine and compare the light sensitivity of two commercially important, phylogenetically different teleost species in terms of melatonin production. Three series of experiments were performed on both Atlantic salmon and European sea bass. First, a range of light intensities were tested ex vivo on pineal melatonin production in culture during the dark phase. Then, light transmission through the skull was investigated, and finally short-term in vivo light sensitivity trials were performed. Results showed that sea bass pineal gland ex vivo are at least 10 times more sensitive to light than that of the salmon. Light intensity threshold in sea bass appeared to be between 3.8 x 10(-5) and 3.8 x 10(-6) W/m2 in contrast to 3.8 x 10(-4) and 3.8 x 10(-5) W/m2 in salmon. These highlighted species-specific light sensitivities of pineal melatonin production that are likely to be the result of adaptation to particular photic niches. Light transmission results showed that a significantly higher percentage of light penetrates the sea bass pineal window relative to salmon, and confirmed that penetration is directly related to wavelength with higher penetration towards the red end of the visible spectrum. Although results obtained in vivo were comparable, large differences between ex vivo and in vivo were observed in both species. The pineal gland in isolation thus appeared to have different sensitivities as the whole animal, suggesting that retinal and/or deep brain photoreception may contribute, in vivo, to the control of melatonin production.

Animals↗
PubMed2005

Muscle and plasma coenzyme Q10 concentration, aerobic power and exercise economy of healthy men in response to four weeks of supplementation.

AIM: To investigate whether 4 weeks of oral supplementation with coenzyme Q10 (CoQ10) would increase its concentration in skeletal muscle, and affect aerobic power (VO2max) and oxygen consumption during submaximal exercise in healthy, physically active men. METHODS: Six volunteers with an average (+/-SD) age of 29.7+/-7.2 years and VO2max of 39.4+/-8.5 mL.kg-1.min-1, participated in a single-blind trial. The experiment consisted of 4 2-week phases, in the order of placebo run-in, CoQ10 supplementation (150 mg daily), CoQ10 (150 mg) plus vitamin E (1,000 IU daily), and placebo wash-out. A three-stage cycle economy test (4 minutes at each of 50, 100, and 150 watts), followed by a VO2max test (25 watts increment every minute till exhaustion), were performed prior to the supplementation and at the end of each phase. Blood samples were taken pre and post each VO2max test, and biopsy samples were obtained from the vastus lateralis muscle pre and post the 4 weeks of CoQ10 supplementation. RESULTS: The plasma CoQ10 concentration was significantly elevated by the supplementation (P<0.05), however, it did not vary significantly pre and post each exercise test (P>0.05). The muscle CoQ10 concentration, VO2max ventilatory threshold, exercise economy and oxygen deficit showed no significant changes in response to the supplementation. CONCLUSION: It was speculated that the non-significant effects of supplementation in healthy, non CoQ10-deficient men could be due to either that the mitochondrial membrane is normally saturated with CoQ10, or that the selected exercise testing protocol and variables were not sensitive enough to detect the effects.

Adult↗
PubMed2004

Glucose self-monitoring in primary care: a survey of current practice.

BACKGROUND: The role of long-term glycaemic control in minimizing long-term complications of diabetes mellitus is evidence-based and national guidelines recommend a target glycosylated haemoglobin level of approximately 7%. Although the role of self-monitoring blood and urine glucose is less well defined, this activity consumes vast National Health Service (NHS) resources. AIMS: The aims of this study were to (i) determine the current practice of glucose self-monitoring in primary care, (ii) determine any changes to therapy made as a result and (iii) compare monitoring and frequency of monitoring in those patients using insulin with those patients taking oral hypoglycaemic agents. METHODS: Postal questionnaire to 311 patients using insulin or oral hypoglycaemic agents identified from three general practices. RESULTS: The response rate was 59.8% (186/311), with the majority of responding patients (n = 158, 87.3%) performing self-monitoring. The patients using insulin were more likely to be self-monitoring than those taking oral therapy (chi(2), P < 0.001, d.f. = 1). The majority of patients who self-monitored and were using insulin (n = 45, 61.1%) altered the dose of insulin if a reading was beyond their target range. However, the majority of patients who self-monitored and were taking oral therapy (n = 48, 68.6%) took no action at all. CONCLUSIONS: Blood glucose self-monitoring was common in those treated with insulin or oral hypoglycaemics, although those using insulin were more likely to self-monitor. Notably many patients, particularly those on oral therapy, took no action based on the results of self-monitoring.

Administration, Oral↗
PubMed2001

The use of a symptom "self-report" inventory to evaluate the acceptability and efficacy of a walking program for patients suffering with chronic fatigue syndrome.

OBJECTIVES: The purpose of this research was to evaluate the effectiveness of the modality of walking as a management strategy for patients suffering with chronic fatigue syndrome (CFS). METHODS: Six males and fourteen females with medically diagnosed CFS (CDC, 1994), completed a 12-week walking program. Prior to starting the program subjects underwent an incremental walking exercise test to predetermine their walking intensity. The SCL-90-R symptom "self-report" questionnaire was administered prior to, and at the completion of, the walking program. RESULTS: At the completion of the 12 weeks of walking, changes in four of the nine SCL-90-R dimensions were significant (somatisation, paranoid ideation, phobic anxiety, and psychoticism). Also significant were the changes in the combination indices, the Global Indices of Distress (GID) and the Positive Symptom Total (PST). CONCLUSION: This group of CFS subjects, by way of "self-report", indicated the possibility of an exercise-induced decrease in psychological stress. The walking intervention may have evoked positive changes in their well-being and, furthermore, provided no evidence of any exacerbation in their symptoms.

Adolescent↗
PubMed2001

Interrater reliability of the Glasgow Coma Scale scoring among nurses in sub-specialties of critical care.

The Glasgow Coma Scale (GCS) is used as an assessment tool to measure the levels of consciousness and coma in patients. This research investigated the reliability of scoring the GCS among registered nurses (RNs) working in five different sub-specialty clinical areas of critical care; general intensive care, neurosurgical intensive care, coronary care, emergency room and post anaesthetic recovery room. Seven video recordings were made of six patients (one patient was recorded twice) having their level of neurological response assessed utilising the GCS. Seventy five RNs (15 from each sub-specialty) viewed each of the GCS assessments on the videotape and rated each patient on the scoring sheet provided. Analysis was performed for all RN subjects as a single group as well as separately for each of the five groups under investigation. The ratings for the first six videos were used to test interrater reliability and the scores from videotape four and seven (same patient) were used to calculate intrarater reliability. Based on comparison with expert scores, of the 75 participants, 38 responded correctly to eye opening responses; only 26 responded correctly to the motor response ratings. However, a better accuracy was achieved in the verbal response category with 67 participants responding correctly. Education qualifications and previous neurosurgical experience were statistically significant with regard to the nurses' accuracy of GCS assessment with p values of 0.004 and 0.043 respectively. The results were consistent with previously published studies demonstrating the motor response rating is most problematic in relation to rate accuracy.

Adult↗
PubMed2000

Neuromuscular responses to explosive and heavy resistance loading.

The EMG power spectrum may shift towards higher frequencies with higher movement velocities. Fatigue, on the other hand, can cause a decrease in the frequency components. The purpose of this study was to examine acute effects of explosive (EE) and heavy resistance (HRE) concentric leg press exercise on muscle force, EMG and blood lactate. The EE included five sets of ten repetitions with 40+/-6% of the isometric maximum at a 100 degrees knee angle performed as explosively as possible. The same number of repetitions was performed in HRE but with a heavier load (67+/-7% of the isometric maximum at a 100 degrees knee angle). Maximal isometric and single concentric actions of different loads, and an isometric fatigue test were measured before and after both exercises. Surface EMG was recorded from the vastus medialis muscles for analyses of average EMG (aEMG) and EMG power spectrum. Muscle fiber composition of the vastus lateralis was determined and blood lactate measured throughout the exercises. Mean power frequency and median frequency were higher during EE than during HRE (P<0.05). They increased during EE (P<0.05) as the exercise progressed, whereas during HRE no change or even slight decreases were observed. Signs of fatigue after pure concentric work were not observed after EE, and even after HRE, possibly due to the relatively small range of motion and short duration of action time, the fatigue was not that extensive. The relative number of fast twitch fibers was correlated (r=0.87, P<0.05) with the change in blood lactate in HRE. It was concluded that there may be a greater use of fast twitch motor units in explosive movements and that instead of fatigue, the present number of concentric actions in explosive exercise seems to have facilitated the neuromuscular system.

Adult↗
PubMed1999

Prolonged incremental tests do not necessarily compromise VO2max in well-trained athletes.

Existing literature suggests that tests for maximal oxygen uptake (VO2max) should last 8-12 minutes and that prolonged tests do not produce valid measurements. The research underlying this suggestion has been performed with non-athletic populations and trained athletes may be more tolerant of longer protocols. Eleven rowers (8 males, 3 females) each underwent four different incremental tests on a standard rowing ergometer in randomised counterbalanced order. One of the tests was continuous with workload increments each minute (IT1MIN). This test lasted an average of 12 min+/-4 s (SEM). The other three tests were discontinuous and consisted of 7 stages separated by 1-minute recovery intervals. Stage durations of 3, 4 and 5 min were used in the different tests (IT3MIN, IT4MIN and IT5MIN). Mean values for VO2max were almost identical for IT1MIN (4.56+/-0.22 L x min(-1)), IT3MIN (4.60+/-0.23 L x min(-1)) and IT4MIN (4.60+/-0.21 L x min(-1)), while IT5MIN produced a significantly lower value (4.47+/-0.21 L x min(-1), p<0.05). There was no significant difference between protocols in peak post-exercise blood lactate concentration (approx 13 mmol x L(-1) in each case), but IT1MIN produced lower peak heart rates and higher respiratory exchange ratios. We conclude that with well trained rowing athletes discontinuous test protocols involving 7 stages of 3-4 minutes duration can provide valid measurements of VO2max.

Adult↗
PubMed1998

The reproducibility of symptoms during a submaximal exercise test in chronic heart failure.

AIMS: The aim of this study was to evaluate the use of a submaximal test with a symptom limited endpoint and to measure the reproducibility of symptoms in patients with CHF. METHODS: Ten patients with chronic heart failure were studied. Based on two maximal treadmill tests an individual protocol using a constant work rate at a submaximal intensity was derived. The projected maximum treadmill time for the constant workrate was between 8 and 17 min. Tests were carried out 1, 2, 4 and 6 weeks after the maximum tests. Every 2.5 min during the submaximal test patients recorded their symptoms of breathlessness and fatigue using computer automated visual analogue (VAS) and Borg CR10 scales. The measure of reproducibility used was the proportion of total variability explained by the between subject variability. RESULTS: Using the VAS scale, general fatigue was reasonably reproducible ranging from 77-86%. For VAS breathlessness reproducibility ranged from 66% to 83%. Reproducibility for breathlessness and fatigue for the Borg CR10 scale was much lower than the VAS scale. Reproducibility for the treadmill times was 51% but increased to 76% if one test of one subject was excluded. CONCLUSIONS: The use of the VAS during submaximal exercise offers a useful means of evaluating symptoms in CHF and potentially their response to treatment. These findings show that individual submaximal protocols can be easily prescribed for CHF patients. Using such an approach, clinically desirable tests lasting around 12 min can be developed. These tests are reasonably reproducible and may provide a useful means of assessing patient disability and the impact of treatment.

Aged↗
PubMed1997

An economic analysis of the Survival and Ventricular Enlargement (SAVE) Study. Application to the United Kingdom.

Recent studies have shown that ACE inhibitors reduce morbidity and mortality after myocardial infarction (MI). While these trials have obvious clinical implications, the widespread introduction of a new treatment for a condition as common as MI also has clear cost implications. The results of the post-MI studies with ACE inhibitors suggest that restricted use of treatment-in high-risk patients-is likely to be most cost effective, whereas treatment of all MI survivors, many of whom are at low risk, will be least cost effective. An approach somewhere in between may maximise clinical benefit at an acceptable cost. Economic analysis may help in deciding how these drugs might be best used after MI. We have conducted a cost-effectiveness and cost-utility analysis of the Survival and Ventricular Enlargement (SAVE) study, which reported the benefit of ACE inhibitors in intermediate-risk patients. Assuming all MI survivors require measurement of left ventricular function before selection for treatment (the approach used in the SAVE study), the incremental cost per life-year gained (LYG), over 4 years, using prophylactic captopril is approximately 10000 pounds sterling (Pounds) [1994 to 1995 values]. The cost per quality-adjusted life-year (QALY) is similar. These incremental cost per LYG and cost per QALY ratios compare favourably with other commonly used symptomatic and prophylactic treatments, and argue for extending post-MI use of ACE inhibitors to intermediate-as well as high-risk patients.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

The pharmacoeconomics of ACE inhibitors in chronic heart failure.

Because heart failure is common and disabling, patients with this condition utilise healthcare resources to a considerable extent. In particular, patients with heart failure frequently require hospital admission, and inpatient care is often protracted. Patients with the most advanced stages of heart failure make the greatest demands on the healthcare system. Expenditure related to the consumption of healthcare resources accounts for the 1 to 2% of total healthcare spending related to heart failure. Between two-thirds and three-quarters of this is due to the costs of hospital care. ACE inhibitors reduce progression of heart failure and also reduce the need for hospitalisation by approximately 30%. In so doing, these drugs substantially or totally offset their cost and the cost of extended life. Five independent economic analyses collectively show ACE inhibitors, at worst, to be very cost effective (in comparison to other cardiovascular therapies), cost neutral or to lead to overall cost savings when used to treat heart failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Car occupant restraint use in Fife: an observational study.

Today road traffic accidents pose a major public health problem with a significant number of deaths and injuries among drivers and passengers of all ages. As part of road safety strategy in Fife the Health Board and Regional Council have carried out an observational study of 7,885 occupants in 4,292 cars to determine the extent of appropriate restraint use in the region. Overall restraint use for urban and non-urban sites was found to be 80%. In car drivers restraint use was 94%. Passengers in all rear seat positions were observed to have a significantly lower level of restraint use, 33% overall compared with 92% overall in the front (chi 2 2,827.9, P << 0.001), with usage of restraint declining with increasing age. Particular problems noted were: the much lower use of restraint among children travelling to and from school, the use of restraint inappropriate to children's age, and the significantly lower level of restraint among taxi drivers and their passengers compared with other cars (chi 2 114.9, P << 0.001). These findings have implications for the promotion of restraint use for all car occupants.

Accidents, Traffic↗
PubMed1990

A comparison of the relative sensitivity of two types of Heaf gun.

A total of 696 secondary school children were given a Heaf test in one forearm with a magnetic head Heaf gun and in the other forearm with a fixed head gun. One week later the results were read blind. In 333 (48%) children the fixed head gun gave a more strongly positive result than the magnetic head gun, while in only 27 (4%) children did the magnetic head gun gives a more strongly positive result. These findings are statistically highly significant (p less than 0.001).

Adolescent↗