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Biomedical subjects

J E Clague

Publications and source records attributed to J E Clague.

At least 19 recordsLinked to original sources
PubMed2000

Hypocapnia and its relation to fear of falling.

OBJECTIVE: To determine if hypocapnia occurs in patients with fear of falling and to explore potential causes of hypocapnia. DESIGN: Observational study in patients who fall with and without fear of falling. SETTING: Rehabilitation wards of an elderly care unit. PATIENTS: Consecutive fallers with (n = 20) and without (n = 10) fear of falling. MAIN OUTCOME MEASURES: End-tidal CO2 (PETCO2) and respiratory rate (RR) responses were measured during sustained isometric muscle contraction (SIMC) (40% of maximum voluntary contraction of quadriceps for 2 min) and during a 5-meter walk. Falls efficacy scale (FES) and Hospital anxiety and depression scale (HAD). RESULTS: Patients with fear of falling had significantly higher FES and HAD scores (p < .01). During SIMC, baseline and nadir PETCO2 levels were significantly lower in patients with a fear of falling (p < .01). During the 5-meter walk, PETCO2 was lower at baseline, at nadir, and at the end of the walk in the fear of falling group than in controls (p < .01). RR was higher at nadir and end of the walk in the fear of falling group than in controls (p < .02). CONCLUSIONS: Hypocapnia may occur in patients with a fear of falling during SIMC and walking. Anxiety seems to be the main cause, but muscle weakness may contribute. Breathing or relaxation techniques and reconditioning may have a role in treating fear of falling in the rehabilitation setting.

Accidental Falls↗
PubMed2000

New approach to risk determination: development of risk profile for new falls among community-dwelling older people by use of a Genetic Algorithm Neural Network (GANN).

BACKGROUND: Falls risk in older people is multifactorial and complex. There is uncertainty about the importance of specific risk factors. Genetic algorithm neural networks (GANNs) can examine all available data and select the best nonlinear combination of variables for predicting falls. The aim of this work was to develop a risk profile for operationally defined new falls in a random sample of older people by use of a GANN approach. METHODS: A random sample of 1042 community-dwelling people aged 65 and older, living in Nottingham, England, were interviewed at baseline (1985) and survivors reinterviewed at a 4-year follow-up (n = 690). The at-risk group (n = 435) was defined as those survivors who had not fallen in the year before the baseline interview. A GANN was used to examine all available attributes and, from these, to select the best nonlinear combination of variables that predicted those people who fell 4 years later. RESULTS: The GANN selected a combination of 16 from a potential 253 variables and correctly predicted 35/114 new fallers (sensitivity = 31%; positive predictive value = 57%) and 295/321 nonfallers (specificity = 92%; negative predictive value = 79%); total correct = 76%. The variables selected by the GANN related to personal health, opportunity, and personal circumstances. CONCLUSIONS: This study demonstrates the capacity of GANNs to examine all available data and then to identify the best 16 variables for predicting falls. The risk profile complements risk factors in the current literature identified by use of standard and conventional statistical methods. Additional data about environmental factors might enhance the sensitivity of the GANN approach and help identify those older people who are at risk of falling.

Accidental Falls↗
PubMed1999

Difficulties in measuring the effect of testosterone replacement therapy on muscle function in older men.

Muscle wasting in older men may be related to androgen deficiency. We have assessed the effect of testosterone replacement therapy on muscle function in the upper and lower limbs of older (age > 60 years) men with blood testosterone levels < 14 nmol/L. Subjects (n = 7 per group) received testosterone enanthate 200 mg i.m. or placebo every 2 weeks in a double blind study over a 12-week period and underwent muscle testing every 4 weeks. A significant increase in blood levels of testosterone and a reduction in levels of sex hormone binding globulin occurred in the treatment group. Total body mass, haemoglobin and packed cell volume also increased significantly (p < 0.05). No improvements in handgrip strength, isometric strength of knee flexors and extensors or leg extensor power were seen in either group. Wide variability in all measures of muscle function were observed in these elderly men suggesting that very large study groups would be required to determine potential treatment benefits on muscle function.

Aged↗
PubMed1999

A study of infection in elderly nursing/residential home and community-based residents.

It is commonly believed that patients admitted to hospital from nursing homes/residential homes (NHRH) with infections are less likely to respond to treatment and have a higher fatality rate than counterparts admitted from their own homes ('the Community'). It is also believed that NHRH's harbour a reservoir of unusual and resistant organisms. These preconceptions may influence how these patients are managed. A database of 10593 sequential admissions to a Geriatric Medical unit over a three-year period was used to identify NHRH and community populations with a principal diagnosis of infection. They were investigated using the Department of Microbiology's database. The admission rate in the NHRH group was twice that of the community group. There were no significant differences in length of stay (LOS) [16 +/- 2 vs 17 +/- 2 days (s.e.m.)], or mean survival time (ST)(61 days (37-84) vs 48 days (25-72): 95% confidence intervals) between the two groups. Subgroups of the NHRH group did have significantly different survival times. Fatality rate was not significantly different between the NHRH (40%) or Community (35%) groups. Both the NHRH and community group underwent very similar levels of investigation (189 vs 200 investigations performed). The types and frequencies of pathogen seen in the two groups were very similar.

Aged↗
PubMed1999

The effect of aging on skeletal muscle capillarization in a murine model.

Capillarization of skeletal muscle has been reported to be both maintained and reduced with advancing age. This conflict may represent methodological differences between biopsy studies. We have examined capillarization throughout two muscles, soleus and extensor digitorum longus (EDL), from a well-established colony of aging mice, and related this to fiber number (C/F ratio) and type. Labeling of muscle capillaries was performed with the biotinylated Griffonia (Bandeiraea) simplicifolia lectin (GSL 1) using immunochemistry. The results showed a significant increase in the C/F ratio in the aged mice when compared with the younger (6-month mice soleus = 1.296, 95% CI 1.226-1.366 vs 28-month mice soleus = 1.530, 95% CI 1.488-1.572, p <.001; 6-month mice EDL = 0.881, 95% CI 0.751-1.011 vs 28-month mice EDL = 1.124, 95% CI 1.028-1.220, p = .017). These differences could not be accounted for by changes in fiber type but may reflect loss of fibers. Alternatively, there may be increased angiogenic drive or a failure of downregulation of angiogenesis.

Aging↗
PubMed1999

Serum transferrin receptor assay in iron deficiency anaemia and anaemia of chronic disease in the elderly.

The most common cause of anaemia in the elderly is anaemia of chronic disease (ACD). However, iron deficiency anaemia (IDA) may coexist, and can be difficult to diagnose. The serum transferrin receptor (sTfR) blood test may be a better indicator of iron status as it is not affected by inflammation nor by advancing age. We evaluated it in four groups (10 males, 10 females each): 'young' controls, 'elderly' controls, IDA and ACD. All patients in the IDA group had elevated sTfR levels (mean +/- SD 65.2 +/- 17.7 nmol/l). All 'young' controls had normal sTfR (22.3 +/- 7.3 nmol/l) and ferritin levels (92.7 +/- 61.1 micrograms/l). Although all subjects in the 'elderly' controls and ACD group had normal, and raised or normal serum ferritin, respectively (88 +/- 62.3 micrograms/l; 631.2 +/- 509.5 micrograms/l), three (15%) 'elderly' controls and four (20%) ACD patients had raised sTfR levels, suggesting depleted iron stores. Bone-marrow aspirates were available in 3/4 ACD patients with raised sTfR. Haemosiderin was absent in two. The sTfR blood test is comparable to serum ferritin in diagnosing IDA in the elderly but also seems capable of differentiating ACD from IDA. Its potential as a non-invasive test of iron status, especially in elderly anaemic patients, deserves further evaluation.

Adult↗
PubMed1999

Injury in the aging: recovery and rehabilitation.

Interest in how victims of traumatic injuries recover is increasing and a number of observational studies have now been done. There are very few intervention studies aimed at enhancing recovery, but there will be more as our knowledge base grows. Older recipients of traumatic injuries differ from the young in the types of injuries they sustain, in the way they respond to their injuries and in the consequences of even relatively minor injuries on their future independence. In this paper, we summarise our understanding of recovery after injury and consider this in more depth for older people with specific injuries.

Accidental Falls↗
PubMed1997

Improving outpatient clinic efficiency using computer simulation.

To assess and plan alterations in outpatient clinic structure, produces a computer simulation of an outpatient clinic based on detailed time and role measurements from the authors' clinic. The stimulation which used an object-oriented design method is able to indicate the impact of changes in clinic structure using patient and doctor waiting times in clinic as endpoint measures. The effects of changes in clinic size, consultation time, patient mix, appointment scheduling and non-attendance were examined. We found that patient waiting time could be shortened considerably by using an optimizing appointment scheduler to determine appointment intervals. Clinic mix influences patient waiting time, which was shorter with a 1 in 4 ratio of new to follow-up patients. In mixed clinics, new patients appointments are optimally spread throughout the clinic to reduce patient waiting time. In all new or all follow-up clinics, waiting time is improved if the appointment interval reflects the consultation time. Computer modelling can help in optimizing clinic management so improving the delivery of care in outpatient services.

Appointments and Schedules↗
PubMed1997

Older people's perceptions about symptoms.

BACKGROUND: Little is known of the nature and origins of the attitudes that older people have towards ageing, disease, and medical treatments. Several studies on older people in the community have suggested under-reporting of symptoms. There may be several reasons for this, including the possibility that some older people regard disease processes as a natural feature of ageing and, consequently, feel that medical intervention may have little to offer. AIM: To investigate the perceptions of older people about the significance of symptoms and what action they would take in response to particular symptoms. METHOD: Thirty-three men and 77 women attending social clubs (median age 78 years) were opportunistically selected and assessed using a supervised questionnaire. RESULTS: Many symptoms classically associated with common diseases were often considered to represent disease as well as to be normal for old people. Most would consult a doctor if they were to experience them. Some important symptoms, such as blackouts or paralysis of a limb, were not considered to be normal. Non-specific symptoms of psychiatric disturbances were also frequently considered normal but were not considered to represent disease. Whether or not a doctor would be consulted was often, but not always, related to whether a symptom was thought to represent a disease. Consulting a pharmacist was seldom considered appropriate. CONCLUSIONS: Doctors working with elderly people need to consider how beliefs about health and disease might affect what is reported to them. Specific enquiry needs to be made about symptoms of psychiatric disturbances. These findings suggest that there is a case for increased health education at retirement age.

Aged↗
PubMed1996

Effect of sustained inspiratory loading on respiratory sensation and CO2 responsiveness in normal humans.

1. To examine the effects of sustained resistive loading on the relationship between inspiratory effort sensation and respiratory drive (P0.1) and to determine if the change in CO2 responsiveness after sustained loading is accompanied by altered effort perception, hypercapnic responses were measured before, immediately after and 15 min after sustained resistive loading in seven subjects (six men, one woman). Sustained resistive loading was set to exceed a diaphragm tension-time index of 0.2. 2. Mean time to task failure during sustained loading was 17.7 min (range 12.5-22.5 min). The mean inspiratory effort sensation score rose from 3.4 (SEM 0.8) to 8.1 (0.8), whereas P0.1 fell from 29.5 (3.6) to 18.1 (3.6) cmH2O. 3. Immediately after loading the slopes of the ventilatory and sensory responses to CO2 fell (ventilatory response: before loading 16.7 (2.4) lmin-1kPa-1, immediately after loading 7.88 (2.18)lmin-1kPa-1; sensory response: before loading 1.95 (0.38) units/kPa; immediately after loading 1.12 (0.38) units/kPa; P < 0.05. Changes reverted to preloading levels by 15 min. 4. Sustained loading can lead to a dissociation between respiratory drive, as reflected by P0.1, and inspiratory effort sensation, and this disturbance can persist once the load is removed. Impaired sensory perception may be the primary determinant of the change in CO2 responsiveness seen after sustained resistive loading.

Adult↗
PubMed1995

Muscle imaging in health and disease.

Muscle imaging has been used largely as an adjunct in the assessment of patients with muscle disease and has been reported in descriptive terms only. Developments in computer-based image analysis techniques applied to muscle have enabled the quantification of muscle images using ultrasonography, computed tomography and magnetic resonance techniques. In conjunction with physiological measurements of muscle force, accurate determinations of muscle section area have allowed the determination of force per unit of cross-sectional area. This important measurement is essential if therapeutic approaches in muscle disease are to be adequately assessed. In this review the uses and merits of different imaging techniques are described with reference to new developments in quantitative analysis of muscle images and the possible utilisation of these techniques in neuromuscular disease is discussed.

Humans↗
PubMed1994

Operations research survey and computer simulation of waiting times in two medical outpatient clinic structures.

Outpatient services are increasingly recognised as an important component of health care provision and may be improved through the application of modern management techniques. We have performed a time and role audit of consultation and waiting times in two medical clinics using different queuing systems: namely, a serial processing clinic where patients wait in a single queue and a quasi-parallel processing clinic where patients are directed to the shortest queue to maintain clinic flow. Data collected were used to construct a computer simulation of patient flows in clinic. Assessment of patient satisfaction in the clinic process was determined using a self-administered questionnaire. Mean waiting time was shorter in the quasi-parallel processing clinic: 26 (SD 17) minutes compared with 36(24) minutes in the serial processing clinic. In the serial processing clinic 61% of patients waited more than 30 minutes compared with 41% in the quasi-parallel processing clinic. In the serial processing clinic 8% of 142 patients surveyed complained of the time spent waiting. The computer simulation we produced was able to determine waiting times with different clinic structures. The simulation showed that reductions in waiting time up to 30% might be achieved by changing our serial processing clinic to a quasi-parallel processing one. Performance of medical outpatient clinics can be improved by examining and changing clinic management. Computer simulation of outpatient clinics offers a means of assessing the impact of such changes on waiting time in clinic and on waiting lists.

Algorithms↗
PubMed1994

Respiratory effort perception at rest and during carbon dioxide rebreathing in patients with dystrophia myotonica.

BACKGROUND: Breathlessness appears to be closely related to the perception of the outgoing motor command to breathe and should be increased in the presence of muscle weakness. However, breathlessness is not a common symptom in patients with chronic muscle disease who have weak respiratory muscles. The factors that determine the perception of respiratory effort in such patients have not been examined. METHODS: The inspiratory effort sensation during resting breathing and progressive hypercapnia was investigated in 12 patients with dystrophia myotonica with weak respiratory muscles (nine men and three women of mean (SD) age 41.1 (10.5) years; maximum inspiratory pressure 43.1 (17.2) cm H2O) and an age and sex matched control group of normal subjects of mean age 39.6 (10.6) years and a maximum inspiratory pressure of 123 (15.2) cm H2O. RESULTS: During resting breathing with a mouthpiece no differences were seen in inspiratory effort sensation, mouth occlusion pressure, or tidal volume, but inspiratory time and cycle duration were significantly shorter in the patients with dystrophia. Minute ventilation (VE) was significantly higher in the patients (15.8 (4.0) l/min v 12.5 (2.6) l/min), while resting breathing was no more variable in the patients than in controls. The ventilatory response to carbon dioxide (VE/PCO2) was not significantly lower in the patients (14.9 (6.9) l/min/kPa) than in the controls (17.4 (4.3) l/min/kPa). Effort sensation responses to carbon dioxide driven breathing were similar in the control subjects and the patients. With regression analysis of pooled data neither maximum inspiratory pressure nor disease state contributed to perceived inspiratory effort during hypercapnia. CONCLUSIONS: Moderately severe global respiratory muscle weakness does not appear to influence the ventilatory response to rising carbon dioxide tension or the perception of inspiratory effort in patients with dystrophia myotonica.

Adult↗
PubMed1993

Muscle histopathology and physiology in chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is characterized by fatigue at rest which is made worse by exercise. Previous biopsy studies on small numbers of CFS patients have shown a range of morphological changes to which have been attributed fatigue and myalgia. We have now studied 108 patients with CFS or muscle pain and 22 normal volunteers by light and electron microscopy. There was no consistent correlation between symptoms and changes in fibre type prevalence, fibre size, degenerative or regenerative features, glycogen depletion, or mitochondrial abnormalities. Physiological contractile properties of quadriceps (maximal isometric force generation, frequency: force characteristics and relaxation rate) were also examined before and for up to 48 hours after a symptom-limited incremental cycle ergometer exercise test in 12 CFS patients and 12 normal volunteers. Voluntary and stimulated force characteristics were normal at rest and during recovery. Exercise duration was similar in the two groups although CFS patients had higher perceived exertion scores in relation to heart rate during exercise, indicating a reduced effort sensation threshold. On physiological and pathological grounds it is clear that CFS is not a myopathy. Psychological/psychiatric factors appear to be of greater importance in this condition.

Adolescent↗