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Biomedical subjects

J Christie

Publications and source records attributed to J Christie.

At least 19 recordsLinked to original sources
PubMed2006

Abnormal haemoglobin levels in acute coronary syndromes.

BACKGROUND: Anaemia is an adverse prognostic marker in acute coronary syndromes (ACS), but the epidemiology of abnormal haemoglobin levels in such patients is uncertain. AIMS: To investigate the prevalence, nature and predictors of abnormal haemoglobin levels in ACS patients at admission. DESIGN: Observational study. METHODS: All emergency admissions from January to April 2005 were assessed within 24-48 h of hospital admission. ACS patients (unstable angina, non-ST-elevation or ST-elevation myocardial infarction) were enrolled (n = 320, 190 men). Clinical information was recorded. RESULTS: Overall, 71% had unstable angina; 18% non-ST-elevation myocardial infarction (MI), and 11% ST-elevation MI. Mean +/- SD haemoglobin was 14.3 +/- 1.7 g/dl in men and 13.2 +/- 1.5 g/dl in women. Abnormal haemoglobin was more common in men (65, 34%) than in women (34, 22%) (p = 0.013). Anaemia (haemoglobin <13 g/dl in men, or <12.0 g/dl in women) was recorded in 35 (18%) men and 24 (18%) women. All had admission haemoglobin >8 g/dl, and anaemia was usually normocytic. Multivariate predictors of anaemia (OR, 95%CI) were age (1.07, 1.04-1.1) and serum albumin (0.90, 0.81-1.00). Elevated haemoglobin (>16 g/dl) was recorded in 30 (16%) men and 4 (3%) women (p < 0.01), and was more common in ST-elevation MI patients (26%) than in unstable angina or non-ST elevation MI patients (9%) (p = 0.005). In patients who underwent invasive management with a post-procedure haemoglobin the following day (n = 85), 15 (18%) new cases of anaemia were detected. Admission duration correlated with haemoglobin (p < 0.01), creatinine (p < 0.01), troponin I (p < 0.01) and C-reactive protein (p < 0.01). Anaemia was more common in those who died in hospital (3, 60%) than in those who survived (56, 18%) (adjusted p = 0.0135). DISCUSSION: Abnormal haemoglobin levels were common in our ACS admissions. Anaemia was generally mild. Increasing age and interventional management were associated with anaemia, which in turn was associated with adverse in-hospital outcomes. Interventions to prevent and detect anaemia in this setting merit prospective testing.

Anemia↗
PubMed2006

The early response to major trauma and intramedullary nailing.

The stress response to trauma is the summation of the physiological response to the injury (the 'first hit') and by the response to any on-going physiological disturbance or subsequent trauma surgery (the 'second hit'). Our animal model was developed in order to allow the study of each of these components of the stress response to major trauma. High-energy, comminuted fracture of the long bones and severe soft-tissue injuries in this model resulted in a significant tropotropic (depressor) cardiovascular response, transcardiac embolism of medullary contents and activation of the coagulation system. Subsequent stabilisation of the fractures using intramedullary nails did not significantly exacerbate any of these responses.

Animals↗
PubMed2003

Ultra scale-down approach for the prediction of full-scale recovery of ovine polycolonal immunoglobulins used in the manufacture of snake venom-specific Fab fragment.

In this article, we describe a new approach that allows the prediction of the performance of a large-scale integrated process for the primary recovery of a therapeutic antibody from an analysis of the individual unit operations and their interactions in an ultra scale-down mimic of the process. The recovery process consisted of four distinct unit operations. Using the new approach we defined the important engineering parameters in each operation that impacted the overall recovery process and in each case verified its effect by a combination of modelling and experimentation. Immunoglobulins were precipitated from large volumes of dilute blood plasma and the precipitated flocs were recovered by centrifugal separation from the liquor containing contaminating proteins, including albumin. The fluid mechanical forces acting on the precipitate and the time of exposure to these forces were used to define a time-integrated fluid stress. This was used as a scaling factor to predict the properties of the precipitated flocs at large scale. In the case of centrifugation, the performance of a full-scale disc stack centrifuge was predicted. This was achieved from a computational fluid dynamics (CFD) analysis of the flow field in the centrifuge coupled with experimental data obtained from the precipitated immunoglobulin flocs using the scale-down precipitation tank, a rotating shear device, and a standard swing-out rotor centrifuge operating under defined conditions. In this way, the performance of the individual unit operations, and their linkage, was successfully analysed from a combination of modelling and experiments. These experiments required only millilitre quantities of the process material. The overall performance of the large-scale process was predicted by tracking the changes in physical and biological properties of the key components in the system, including the size distribution of the antibody precipitates and antibody activity through the individual unit operations in the ultra scale-down process flowsheet.

Animals↗
PubMed2002

Refractures in patients at least forty-five years old. a prospective analysis of twenty-two thousand and sixty patients.

BACKGROUND: Individuals who sustain a low-energy fracture are at increased risk of sustaining a subsequent low-energy fracture. The incidence of these refractures may be reduced by secondary preventative measures, although justifying such interventions and evaluating their impact is difficult without substantive evidence of the severity of the refracture risk. The aim of this study was to quantify the risk of sustaining another fracture following a low-energy fracture compared with the risk in an age and sex-matched reference population. METHODS: During the twelve-year period between January 1988 and December 1999, all inpatient and outpatient fracture-treatment events were prospectively audited in a trauma unit that is the sole source of fracture treatment for a well-defined local catchment population. During this time, 22,060 patients at least forty-five years of age who had sustained a total of 22,494 low-energy fractures of the hip, wrist, proximal part of the humerus, or ankle were identified. All refracture events were linked to the index fracture in the database during the twelve-year period. The incidence of refracture in the cohort of patients who had sustained a previous fracture was divided by the "background" incidence of index fractures within the same local population to obtain the relative risk of refracture. Person-years at-risk methodology was used to control for the effect of the expected increase in mortality with advancing age. RESULTS: Within the cohort, 2913 patients (13.2%) subsequently sustained a total of 3024 refractures during the twelve-year period. Patients with a previous low-energy fracture had a relative risk of 3.89 of sustaining a subsequent low-energy fracture. The relative risk was significantly increased for both sexes, but it was greater for men (relative risk = 5.55) than it was for women (relative risk = 2.94). The relative risk was 5.23 in the youngest age cohort (patients between forty-five and forty-nine years of age), and it decreased with increasing age to 1.20 in the oldest cohort (patients at least eighty-five years of age). CONCLUSIONS: Individuals who sustain a low-energy fracture between the ages of forty-five and eighty-four years have an increased relative risk of sustaining another low-energy fracture. This increased risk was greater when the index fracture occurred earlier in life; the risk decreased with advancing age. Secondary preventative measures designed to reduce the risk of refracture following a low-energy fracture are likely to have a greater impact on younger individuals.

Age Factors↗
PubMed2001

Negative priming for spatial location?

The term negative priming has been used to describe the deleterious consequences for performance when the current target shares properties with an ignored distractor from the previous trial. Location-based negative priming was first reported by Tipper, Brehaut, and Driver (1990) who used a prime-probe procedure wherein the task was to localize targets defined by their identity (shape). Design imbalances in this seminal study, and others, are illustrated and it is indicated how these might have contaminated the reported effects. The findings, from three experiments using an unbiased design, suggest that negative priming in the spatial location procedure may be more closely related to inhibition of return (IOR), or to the automatic attraction of attention by new objects, than to the concepts of distractor inhibition, episodic retrieval, and feature mismatch, which have traditionally been used to explain negative priming for spatial location.

Adult↗
PubMed2001

The immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) is caused by mutations of FOXP3.

IPEX is a fatal disorder characterized by immune dysregulation, polyendocrinopathy, enteropathy and X-linked inheritance (MIM 304930). We present genetic evidence that different mutations of the human gene FOXP3, the ortholog of the gene mutated in scurfy mice (Foxp3), causes IPEX syndrome. Recent linkage analysis studies mapped the gene mutated in IPEX to an interval of 17-20-cM at Xp11. 23-Xq13.3.

Amino Acid Sequence↗
PubMed2001

The coagulative and cardiorespiratory responses to reamed intramedullary nailing of isolated fractures.

We measured the changes during operation in seven markers of coagulation in a prospective series of 84 patients with fractures of the tibia or femur who were undergoing reamed intramedullary nailing. All patients were also continually monitored using transoesophageal echocardiography to assess marrow embolism. In a subset of 40 patients, intraoperative cardiopulmonary function was monitored, using pulmonary and systemic arterial catheterisation. The procedure produced a significant increase in prothrombin time, activated partial thromboplastin time, the level of prothrombin fragments F1+2 and D-dimers, and a decrease in the fibrinogen level, suggesting activation of both the coagulation and fibrinolytic pathways. There was evidence of both platelet hyper-reactivity and depletion, as estimated by an increase in beta-thromboglobulin levels and a decrease in the platelet count. In the patients who had invasive monitoring there was an incremental increase in mean pulmonary arterial pressure, with the changes being greatest during insertion of the guide-wire and reaming. The change in markers of coagulation, pulmonary artery pressure and arterial oxygen partial pressures correlated with the intraoperative embolic response. Greater changes in these parameters were observed during stabilisation of pathological fractures and in those patients in whom surgery had been delayed for more than 48 hours. Seven patients with pathological fractures developed more severe hypoxic episodes during reaming, which were associated with significantly greater arterial hypoxaemia, a fall in the right ventricular ejection fraction and an increase in the mean pulmonary artery pressure, pulmonary capillary wedge pressure, central venous pressure and the pulmonary vascular resistance index. These changes suggested that the patients had transient intraoperative right heart strain. Eight patients developed significant postoperative respiratory compromise. They all had severe intraoperative embolic responses and, in the three who had invasive monitoring, there was a significantly greater increase in pulmonary artery pressure and alveolar-arterial oxygen gradient, and a fall in the ratio of arterial partial pressure of oxygen to the inspired oxygen concentration. Operative delay, intraoperative paradoxical embolisation and the scores for the severity of the coagulative and embolic responses were predictive of the development of postoperative respiratory complications on univariate logistic regression analysis. On multivariate analysis, however, only the embolic and coagulative scores were significant independent predictors of respiratory complications.

Cardiovascular Diseases↗
PubMed2000

The U.K. NHS economic evaluation database. Economic issues in evaluations of health technology.

OBJECTIVE: The U.K. NHS Economic Evaluation Database (EED) project is commissioned to identify papers on economic evaluations of health technologies and to disseminate their findings to NHS decision makers by means of structured abstracts that are available through a public database and the Cochrane Library. This paper discusses current issues relating to the economic aspects of producing NHS EED abstracts. METHODS: A review of NHS EED was undertaken between 1994 and 1999 to determine the methodologies adopted and issues that influence the usefulness of economic evaluations. Methods adopted to improve the quality of NHS EED abstracts are also reported. RESULTS: Eighty-five percent of NHS EED abstracts are cost-effectiveness analyses (CEAs), 9.3% are cost-utility analyses (CUAs), and only 1.4% are cost-benefit analyses (CBAs). Of the total abstracts, 65.9% are based on single studies, 19.5% on reviews, 3.9% on estimates of effectiveness, and 10.7% on combinations of these sources. Models are utilized in 16.7% of CEAs, 60.2% of CUAs, and 20% of CBAs. Analyses of CBA studies reveal a degree of misuse of well-established definitions. NHS EED internal control mechanisms are reported that provide a means of ensuring that abstracts are based on sound academic principles. CONCLUSIONS: Most economic evaluations are conducted by means of CEA, followed by CUA, while CBA accounts for an extreme minority of cases. Single studies form the principal source of effectiveness data, although models are widely used, principally in CUA. The structure of NHS EED abstracts provides decision makers with the principal results and an interpretation of the relative strengths and weaknesses of economic evaluations.

Abstracting and Indexing↗
PubMed1999

A comparison of the reproducibility and the sensitivity to change of visual analogue scales, Borg scales, and Likert scales in normal subjects during submaximal exercise.

OBJECTIVE: To assess which subjective scale, the visual analogue scale (VAS), the Borg CR10 (Borg) scale, or the Likert scale (LS), if any, is decidedly more reproducible and sensitive to change in the assessment of symptoms. DESIGN: Prospective clinical study. SETTING: Exercise laboratory. PARTICIPANTS: Twenty-three physically active male subjects (mean +/- SD age of 30 +/- 4 years old) were recruited. INTERVENTION: Each subject attended the exercise laboratory on four occasions at intervals of 1 week. Three subjective scales were used: (1) the VAS (continuous scale); (2) the Borg scale (12 fixed points); and (3) the Likert scale (LS; 5 fixed points). Four identical submaximal tests were given (2 min at 60% maximum oxygen uptake [VO(2)max] and 6 min at 70% VO(2)max). Two tests were undertaken to assess the reproducibility of scores that were obtained with each subjective scale. Two other tests were undertaken to assess the sensitivity of each scale to a change in symptom perception: a double-blind treatment with propranolol, 80 mg, (ie, active therapy; to increase the sensation of breathlessness and general fatigue during exercise) or matching placebo. The subjective scale scores were measured at 1 min 30 s, 5 min 30 s, and 7 min 15 s of exercise. Reproducibility was defined as the proportion of total variance (ie, between-subject plus within-subject variance) explained by the between-subject variance given as a percentage. Sensitivity was defined as the effect of the active drug therapy over the variation within subjects. RESULTS: Overall, the VAS performed best in terms of reproducibility for breathlessness and general fatigue, with reproducibility coefficients as high as 78%. For sensitivity, the VAS was best for breathlessness (ratio, 2.7) and the Borg scale was most sensitive for general fatigue (ratio, 3.0). The relationships between the respective psychological and physiologic variables were reasonably stable throughout the testing procedure, with overall typical correlations of 0.73 to 0.82 CONCLUSION: This study suggests that subjective scales can reproducibly measure symptoms during steady-state exercise and can detect the effect of a drug intervention. The VAS and Borg scales appear to be the best subjective scales for this purpose.

Adrenergic beta-Antagonists↗
PubMed1998

Seasonal affective disorder among primary care consulters in January: prevalence and month by month consultation patterns.

BACKGROUND: Little is known about the prevalence or the consultation patterns of patients with seasonal affective disorder (SAD) in primary care settings. METHODS: Patients aged 16-64 years consulting a general practitioner (G.P.) during a three week period in January were screened with the Seasonal Pattern Assessment Questionnaire (SPAQ). Interview-confirmed cases of SAD (N = 33) were matched by age and sex to controls without seasonal morbidity and primary care consultation patterns were compared over a 5 year period. RESULTS: Of 692 patients screened, 64 (9.3%) satisfied SPAQ criteria for winter SAD. Patients with SAD showed no winter excess of consultations but were high year round consulters, averaging 1.8 times more consultations than controls. CONCLUSIONS: High levels of SAD caseness on the SPAQ were found among patients consulting in primary care during January. Possible explanations for the high non-seasonal consultation patterns among SAD patients include somatisation and diagnostic inaccuracies. LIMITATIONS: Diagnostic criteria for SAD, and the SPAQ in particular, may be over-inclusive. The SPAQ completion rate (about 39% of eligible patients consulting a G.P.) was relatively low. CLINICAL RELEVANCE: Patients with SAD (using SPAQ criteria) commonly consult their G.P.s in winter but frequency, rather than seasonality, of consultation may be a better guide to diagnosing SAD in primary care.

Adolescent↗
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↗
PubMed1998

Unilateral adrenal mass due to Mycobacterium kansasii in an AIDS patient.

Infection with Mycobacterium kansasii in patients with acquired immunodeficiency syndrome usually involves the lung or disseminated infection. We report a case of infection with M kansasii confined to the adrenal gland and possibly to an adjacent vertebral body that presented as a fever of undetermined origin.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Apolipoprotein E and alpha-1 antichymotrypsin polymorphism genotyping in Alzheimer's disease and in dementia with Lewy bodies. Distinctions between diseases.

The possibility of gene interactions in Alzheimer's disease (AD) has been suggested by the finding of an association of the AA genotype of the alpha-1 antichymotrypsin (AACT) gene and the apolipoprotein E (apoE) epsilon 4/4 genotype in AD. We tested this possibility by genotyping a large series of clinically and neuropathologically confirmed cases of AD and a series of cases with dementia with Lewy bodies (DLB) with a matched control group for the AACT locus and apoE. ApoE genotyping showed the established finding of an increased frequency of the apoE epsilon 4 allele in AD and in DLB. The AD and DLB groups differed between each other with a higher epsilon 2 allele frequency and a reduced incidence of the epsilon 4/4 genotype in DLB. Differences in the apoE frequencies may account for some of the differences between the two diseases. No association was found for the AACT A allele in AD or DLB in the groups as a whole or when stratified with respect to apoE, with the exception of a trend showing an increased incidence of the apoE epsilon 4/4 AACT AA genotype combination in AD patients (chi 2 = 3.18, p = 0.07), although in DLB this was not apparent (chi 2 = 0.0, p = 1.0). The AACT A allele is not a major risk factor for late-onset AD or DLB.

Aged↗
PubMed1998

Epidemiology of fractures in 15,000 adults: the influence of age and gender.

We report a prospective study of the incidence of fractures in the adult population of Edinburgh, related to age and gender. Over a two-year period, 15,293 adults, 7428 males and 7865 females, sustained a fracture, and 5208 (34.0%) required admission. Between 15 and 49 years of age, males were 2.9 times more likely to sustain a fracture than females (95% CI 2.7 to 3.1). Over the age of 60 years, females were 2.3 times more likely to sustain a fracture than males (95% CI 2.1 to 2.4). There were three main peaks of fracture distribution: the first was in young adult males, the second was in elderly patients of both genders, mainly in metaphyseal bone such as the proximal femur, although diaphyseal fractures also showed an increase in incidence. The third increase in the incidence of fractures, especially of the wrist, was seen to start at 40 years of age in women. Our study has also shown that 'osteoporotic' fractures became evident in women earlier than expected, and that they were not entirely a postmenopausal phenomenon.

Adolescent↗
PubMed1997

Variation in the diagnosis of vesicoureteric reflux using micturating cystourethrography.

Variability in the interpretation of micturating cystourethrography by paediatric radiologists for the diagnosis of vesicoureteric reflux in children was evaluated. All 265 micturating cystourethrograms (MCUs) that were available from 304 consecutive children aged 0.5-61 months-who were investigated after their first urine infection between 1993 and 1995 as part of a prospective cohort study-were selected for interpretation. Three experienced paediatric radiologists from the same department independently interpreted the MCUs according to the grading system of the International Reflux Study in Children, from grades 0 to V, with the presence of intrarenal reflux also noted. Apart from being informed that urine infection was the indication for the MCU, no other clinical information was given to the radiologists. The indices of variability used were the percentage of agreement and the kappa statistic, expressed as a percentage. Both measures were weighted with integers representing the number of categories from perfect agreement. Disagreement was analysed for children and kidneys. For the diagnosis of vesicoureteric reflux in individual patients, including grade, the percentage of agreement was 96%-97% (kappa 90%-91%) and the weighted percentage of agreement was 96%-98% (weighted kappa 93%-94%). The same high level of agreement was present for individual kidneys, with a percentage of agreement of 97%-98% (kappa 89%-92%) and a weighted percentage of agreement of 98%-99% (kappa 94%-95%). There was near perfect agreement in the interpretation of radiological micturating cystourethrography among three experienced paediatric radiologists for the diagnosis and grade of vesicoureteric reflux. Any variations in the medical care of children suspected of having vesicoureteric reflux are not explained by differences in the reporting of this diagnostic test.

Child↗