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Biomedical subjects

J Dawson

Publications and source records attributed to J Dawson.

At least 19 recordsLinked to original sources
PubMed2007

Amnesia and driving.

Two experienced drivers who developed severe amnesia due to bilateral hippocampal lesions participated in a series of standardized challenges of driving performance and knowledge of driving rules. During drives in a high fidelity simulator and on the road in an instrumented vehicle, they demonstrated vehicle control similar to that of normal drivers on measures of steering, speed control, safety errors, and driving with distraction. Their knowledge of driving rules, safety procedures, and road sign meaning also was normal. However, both participants were impaired at following route directions, and both had unsafe responses in a difficult crash avoidance scenario on the simulator. These findings suggest that memory impairment acquired by experienced drivers does not impair most aspects of driving performance, but may increase safety risk under some challenging circumstances.

Amnesia↗
PubMed2006

Medical optimisation can reduce morbidity and mortality associated with elective aortic aneurysm repair.

OBJECTIVES: Patients with aortic aneurysms have significant comorbidities which influence outcome. Our practice includes comprehensive assessment to identify comorbidities, allowing subsequent medical optimisation prior to aneurysm repair. The aim of this study was to assess this process and to identify any factors predictive of outcome. DESIGN: Prospective observational study. MATERIALS: Medical case notes of 200 patients referred with aortic pathology. METHODS: Data analysed included preoperative, perioperative and postoperative factors. Multiple logistic regression analysis was performed to identify predictors of outcome. RESULTS: Following assessment 17 patients (8.5%) were found to be unfit for intervention and 165 patients (82.5%) proceeded to aneurysm repair. In this group assessment uncovered previously undiagnosed cardiac, respiratory and renal comorbidity in 19%, 57% and 29% of patients respectively. Multiple logistic regression analysis indicated that optimisation by a renal physician reduced post-operative renal impairment (OR 0.12, 95% CI 0.03-0.45, P=0.002) while optimisation by a cardiologist reduced respiratory complications (OR 0.7, 95% CI 0.05-0.99, P=0.049). An abnormal echocardiogram was associated with pneumonia (OR 6.9, 95% CI 1.6-29, P=0.01) and death (OR 7.9, 95% CI 1.15-54, P=0.036). CONCLUSION: Pre-operative assessment identifies previously undiagnosed comorbidity in a significant proportion of patients. Subsequent medical optimisation may reduce post-operative morbidity and mortality.

Aged↗
PubMed2006

y+ LAT-1 mediates transport of the potent and selective iNOS inhibitor, GW274150, in control J774 macrophages.

This study has characterised the transport mechanism(s) for the novel and selective inhibitor of inducible nitric oxide synthase (iNOS), GW274150, in murine macrophage J774 cells. Transport of GW274150 was saturable (K(m) = 0.24 +/- 0.01 mM and V(max) of 8.5 +/- 0.12 pmol.microg protein(-1) min(-1)), pH-insensitive and largely Na(+)-independent. Transport was also susceptible to trans-stimulation and was significantly inhibited by a 10-fold excess of L-arginine, L-lysine, L-leucine, L-methionine, L-glutamine and 6-diazo-5-oxo-L-norleucine but not by other amino acids or by N-ethylmaleimide. More importantly, the inhibitions caused by the neutral amino acids were critically dependent on Na(+). These results strongly implicate system y(+)L in the transport of GW274150. Northern blot analysis confirmed this by revealing the presence of transcripts for y(+)LAT-1 but not y(+)LAT-2. Thus, taken together, our data show for the first time that J774 macrophages express y(+)LAT-1 transporters and that these carriers mediate transport of GW2741500 at least in these cells.

Amino Acid Transport System y+L↗
PubMed2006

Contemporary management of the infra-renal abdominal aortic aneurysm.

Abdominal aortic aneurysms (AAAs) principally affect men over 60 years of age. Aneurysms are usually asymptomatic and detected coincidentally or following the onset of symptoms. Elective repair of an AAA is considered when the diameter reaches 5.5cm or annual expansion exceeds 1 cm. Rupture represents a catastrophic event and carries an unacceptably high mortality. The advent of endovascular repair heralds an improvement in operative outcome for this disease process. In this review we provide an overview of the recent trials investigating the management of non-ruptured and ruptured aneurysms and the strategies that may be invoked to lower the mortality of this disease process

Aortic Aneurysm, Abdominal↗
PubMed2005

Prevalence and incidence of adults consulting for shoulder conditions in UK primary care; patterns of diagnosis and referral.

OBJECTIVES: To estimate the national prevalence and incidence of adults consulting for a shoulder condition and to investigate patterns of diagnosis, treatment, consultation and referral 3 yr after initial presentation. METHODS: Prevalence and incidence rates were estimated for 658469 patients aged 18 and over in the year 2000 using a primary care database, the IMS Disease Analyzer-Mediplus UK. A cohort of 9215 incident cases was followed-up prospectively for 3 yr beyond the initial consultation. RESULTS: The annual prevalence and incidence of people consulting for a shoulder condition was 2.36% [95% confidence interval (CI) 2.32-2.40%] and 1.47% (95% CI 1.44-1.50%), respectively. Prevalence increased linearly with age whilst incidence peaked at around 50 yr then remained static at around 2%. Around half of the incident cases consulted once only, while 13.6% were still consulting with a shoulder problem during the third year of follow-up. During the 3 yr following initial presentation, 22.4% of patients were referred to secondary care, 30.8% were prescribed non-steroidal anti-inflammatory drugs and 10.6% were given an injection by their general practitioner (GP). GPs tended to use a limited number of generalized codes when recording a diagnosis; just five of 426 possible Read codes relating to shoulder conditions accounted for 74.6% of the diagnoses of new cases recorded by GPs. CONCLUSIONS: The prevalence of people consulting for shoulder problems in primary care is substantially lower than community-based estimates of shoulder pain. Most referrals occur within 3 months of initial presentation, but only a minority of patients are referred to orthopaedic specialists or rheumatologists. GPs may lack confidence in applying precise diagnoses to shoulder conditions.

Adolescent↗
PubMed2005

A review of biological factors implicated in abdominal aortic aneurysm rupture.

Abdominal aortic aneurysm (AAA) rupture is the 13th commonest cause of death in the Western World. Although considerable research has been applied to the aetiology and mechanism of aneurysm expansion, little is known about the mechanism of rupture. Aneurysm rupture was historically considered to be a simple physical process that occurred when the aortic wall could no longer contain the haemodynamic stress of the circulation. However, AAAs do not conform to the law of Laplace and there is growing evidence that aneurysm rupture involves a complex series of biological changes in the aortic wall. This paper reviews the available data on patient variables associated with aneurysm rupture and presents the evidence implicating biological factors in AAA rupture.

Aorta, Abdominal↗
PubMed2005

Assessment of the Lequesne index of severity for osteoarthritis of the hip in an elderly population.

OBJECTIVE: To assess the measurement properties of the Lequesne index of severity for osteoarthritis of the hip (LISOH) together with its overall usefulness with reference to the original stated aims. METHOD: Postal questionnaire was sent to a random sample of 5500 Oxfordshire residents, aged 65 and above. Respondents with hip symptoms at baseline (but without verification of a diagnosis) were sent an identical follow-up questionnaire 12 months later. The questionnaire included a general health section, including the Short Form-36 survey, and a hip section which began with a screening question about hip pain. Respondents who reported having a prolonged episode of hip pain were asked to complete the LISOH. RESULTS: At baseline, response rate of 66.3% (3341/5039) was obtained from eligible participants; 19.2% (610/3175) of respondents reported having hip pain. Internal reliability (Cronbach's alpha) was 0.84 (95% CI: 0.81-0.86) for all 11 items of the LISOH; however, factor analysis identified two factors (sub-scales): "function and mobility" and "pain and discomfort". Rasch analysis revealed that the two factors were only unidimensional when applied to sub-groups of respondents. Convergent validity of the LISOH was questionable, as the "function and mobility" factor was more highly correlated with SF-36 bodily pain score than was the "pain and discomfort" factor. The assessment of sensitivity over time was problematic due to changing patterns of symptomatic weight-bearing joints over time. CONCLUSIONS: The current study identifies major limitations with the LISOH--particularly if used as a single composite measure.

Aged↗
PubMed2005

Endovascular stent graft repair of mycotic aneurysms of the thoracic aorta.

Traditional open surgical repair for mycotic aneurysms of the thoracic aorta is associated with significant morbidity and mortality. Endovascular repair has been reported as an alternative treatment in patients with mycotic thoracic aneurysms. This article reports our experience of endovascular stent graft placement in three patients with mycotic aneurysms of the thoracic aorta and compares the results with similar reports on the literature.

Aged↗
PubMed2004

Angiogenesis inhibition by the novel VEGF receptor tyrosine kinase inhibitor, PTK787/ZK222584, causes significant anti-arthritic effects in models of rheumatoid arthritis.

OBJECTIVE AND DESIGN: To examine the effects of PTK787/ZK222584, a novel angiogenesis inhibitor, in a series of in vivo models of arthritis and inflammation. MATERIALS: The granulomatous air pouch and antigen-induced arthritis models were established in female OFA-1 mice. Female DBA/1LacJ mice were used for the collagen-induced arthritis model and male OFA rats were used for the carrageenan oedema and hyperalgesia tests. TREATMENT: PTK787/ZK222584 was administered p.o., once daily, at various concentrations. Diclofenac (3 mg/kg) and DUP697 (0.5 mg/kg) were also given p.o, once daily. METHODS: The anti-angiogenic effects of PTK787/ZK222584 were directly assessed in the granulomatous air pouch model using the carmine red assay. The anti-arthritic effects of this compound were further examined in the mouse antigen-induced and collagen-induced models of arthritis, using macroscopic observations (calliper measurements of joints) and histological scores (as assessed by degree of cellularity, cell infiltration and erosions and proteoglycan loss). All compounds were administered orally. PTK787/ZK222584 at 10, 30, 50 and 100 mg/kg and positive control compounds, diclofenac and DUP697 at 3 mg/kg and 0.5 mg/kg, respectively. In addition, the effects of PTK787/ZK222584 in the rat carrageenan oedema model and Randall Selitto hyperalgesia test were observed. RESULTS: PTK787/ZK222584 treatment caused dose dependent reduction in the vascularity of the granulomatous air pouch model. It inhibited knee swelling by 40% in antigen-induced arthritis, at the dose of 30 mg/kg p.o., once daily (s.i.d). and inhibited both severity scores (by 51%) and global histological scores in mice with collagen-induced arthritis following oral treatment (45 mg/kg p.o.), as compared to control animals. PTK787/ZK222584 demonstrated no effects on inflammatory mediators in the VEGF-independent rat carrageenan model and displayed interesting analgesic activity in the Randall Selitto test in the acute setting. CONCLUSIONS: The anti-arthritic effects of this specific, receptor tyrosine kinase inhibitor compound appear to be mediated by anti-angiogenic actions. This study represents a new indication for PTK787/ZK222584, namely, rheumatoid arthritis and further supports the belief that angiogenesis inhibition is likely to be beneficial in the therapy of this condition.

Angiogenesis Inhibitors↗
PubMed2004

Epidemiology of hip and knee pain and its impact on overall health status in older adults.

OBJECTIVES: To obtain prevalence rates of hip and knee pain in elderly people and compare combinations of symptoms with overall health status. METHODS: We performed a cross-sectional postal survey of a random sample of 5500 Oxfordshire residents aged 65 yr and older. Prevalence estimates were based on the screening question: 'During the past 12 months, have you had pain in or around either of your hip/knee joints on most days for one month or longer?' Overall health status was assessed with the SF-36 questionnaire. RESULTS: The response rate was 66.3% (3341/5039 eligible people), and was highest (approximately reverse similar 72%) for the 65-74 yr age-group. The percentage reporting hip pain was 19.2% [95% confidence interval (CI) 17.9-20.6], and 32.6% (95% CI 31.0-34.3) reported knee pain. The percentage reporting hip and knee pain was 11.3%, and 40.7% reported hip or knee pain. Less than half (48%) of the symptomatic respondents had unilateral problems affecting one hip or knee joint only. SF-36 scores worsened as the number of symptomatic hip and knee joints increased (P<0.001 for physical function, physical role limitation and bodily pain). CONCLUSIONS: Patterns of hip and knee symptoms are complex in older people. Amongst the symptomatic, most have more than one hip/knee affected. This has implications for treatment and health status measurement. In the absence of hip and knee symptoms, general health status scores of elderly people are similar to those of people aged under 65 yr.

Aged↗
PubMed2003

Breast cancer teams: the impact of constitution, new cancer workload, and methods of operation on their effectiveness.

National guidance and clinical guidelines recommended multidisciplinary teams (MDTs) for cancer services in order to bring specialists in relevant disciplines together, ensure clinical decisions are fully informed, and to coordinate care effectively. However, the effectiveness of cancer teams was not previously evaluated systematically. A random sample of 72 breast cancer teams in England was studied (548 members in six core disciplines), stratified by region and caseload. Information about team constitution, processes, effectiveness, clinical performance, and members' mental well-being was gathered using appropriate instruments. Two input variables, team workload (P=0.009) and the proportion of breast care nurses (P=0.003), positively predicted overall clinical performance in multivariate analysis using a two-stage regression model. There were significant correlations between individual team inputs, team composition variables, and clinical performance. Some disciplines consistently perceived their team's effectiveness differently from the mean. Teams with shared leadership of their clinical decision-making were most effective. The mental well-being of team members appeared significantly better than in previous studies of cancer clinicians, the NHS, and the general population. This study established that team composition, working methods, and workloads are related to measures of effectiveness, including the quality of clinical care.

Adult↗
PubMed2003

An investigation of risk factors for symptomatic osteoarthritis of the knee in women using a life course approach.

STUDY OBJECTIVE: To explore risk factors for symptomatic knee osteoarthritis (OAK) in women, which included wearing high heeled shoes. DESIGN: Matched case-control study. Exposure information obtained by interview, included details about past footwear. Self reported weight and height data obtained representing when women left school, were aged 36-40 and were aged 51-55. Regular work activities (including periods when homemaker or carer), smoking, and hormone related data gathered using a life-grid. SETTING: Interviews in participants' homes. Cases identified from orthopaedic hospital surgical waiting list, controls identified by general practitioners (GPs) PARTICIPANTS: Women aged 50 to 70 years. Cases awaiting knee replacement surgery. Controls, who had no past knee surgery and no knee pain in the past three years, were matched for age and GP. Altogether 111 eligible women were interviewed (29 cases, 82 controls). MAIN RESULTS: Univariate analyses identified several significant associations with OAK including past knee injury, arthritis of the feet, heavy smoking, being overweight (BMI 25 or above) and various occupational activities. Virtually all measures of high heeled shoes use were associated with reduced risk of OAK, although none of these findings were statistically significant. In multivariate analysis only BMI 25 or above at age 36-40 remained significantly associated with OAK (OR 36.4, 95% CI 3.07 to 432, p=0.004), although weak evidence suggested certain occupational activities might increase risk. Weight gain in early adult life was particularly pronounced among cases. CONCLUSIONS: Being overweight before the age of 40 considerably increased the risk of subsequent symptomatic OAK in women. Wearing high heeled shoes did not.

Adult↗
PubMed2001

Increased attentional blink after focal cerebral lesions.

BACKGROUND: Once a person identifies a visual object, the ability to detect a second object is impaired for the next few hundred milliseconds. This attentional blink is reported to increase in subjects with neglect due to acute right hemisphere lesions. METHOD: To examine neural substrates of the attentional blink, the authors examined the performance of 13 subjects with chronic focal brain lesions visualized by MRI and nine control subjects without neurologic impairments on a rapid serial visual presentation task that used letters as targets. RESULTS: Attentional blink length in the lesion group was more than twice that of controls (p < 0.05). The magnitude of the attentional blink deficit was greatest when the second target appeared 200 ms after the first target, recovering close to baseline by 1,200 ms. Abnormal attentional blink occurred (even in the absence of neglect) with lesions in the occipitotemporal areas (associated with "object" vision) and the prefrontal cortices (thought to mediate visual working memory). CONCLUSIONS: Attentional blink length and attentional blink magnitude measure different components of the attentional blink process. Abnormal attentional blink can occur with different chronic focal brain lesions in a network of structures for vision and attention, and it has no special status in hemispatial neglect. Abnormal attentional blink may help explain difficulties on rapid, visually demanding cognitive tasks such as reading and automobile driving and may explain performance deficits in brain damaged patients with nonspatial disorders of visual processing.

Adult↗
PubMed2001

Serum amyloid A (apoSAA) expression is up-regulated in rheumatoid arthritis and induces transcription of matrix metalloproteinases.

The acute-phase reactant rabbit serum amyloid A 3 (SAA3) was identified as the major difference product in Ag-induced arthritis in the rabbit, a model resembling in many aspects the clinical characteristics of rheumatoid arthritis (RA) in humans. In Ag-induced arthritis, up-regulated SAA3 transcription in vivo was detected in cells infiltrating into the inflamed joint, in the area where pannus formation starts and, most notably, also in chondrocytes. The proinflammatory cytokine IL-1beta induced SAA3 transcription in primary rabbit chondrocytes in vitro. Furthermore, rSAA3 protein induced transcription of matrix metalloproteinases in rabbit chondrocytes in vitro. In the human experimental system, IL-1beta induced transcription of acute-phase SAA (A-SSA; encoded by SAA1/SAA2) in primary chondrocytes. Similar to the rabbit system, recombinant human A-SAA protein was able to induce matrix metalloproteinases' transcription in chondrocytes. Further, immunohistochemistry demonstrated that A-SAA was highly expressed in human RA synovium. A new finding of our study is that A-SSA expression was also detected in cartilage in osteoarthritis. Our data, together with previous findings of SAA expression in RA synovium, suggest that A-SAA may play a role in cartilage destruction in arthritis.

Amino Acid Sequence↗
PubMed2001

Effect of the total motile sperm count on the efficacy and cost-effectiveness of intrauterine insemination and in vitro fertilization.

OBJECTIVE: To determine prognostic factors for achieving a pregnancy with intrauterine insemination (IUI) and IVF. To compare the effectiveness and cost-effectiveness of IUI and IVF based on semen analysis results. DESIGN: Retrospective cohort study. SETTING: Academic university hospital-based infertility center. PATIENT(S): One thousand thirty-nine infertile couples undergoing 3,479 IUI cycles. Four hundred twenty-four infertile couples undergoing 551 IVF cycles. INTERVENTION(S): IUI and IVF treatment. MAIN OUTCOME MEASURE(S): Multiple logistic regression analysis was used to assess the significance of prognostic factors including a woman's age, gravidity, duration of infertility, diagnoses, use of ovulation induction, and sperm parameters for predicting the outcomes of clinical pregnancy and live birth rate after the first cycle of IUI and IVF. The relative effectiveness and cost-effectiveness of these treatments were then determined based on sperm count results. RESULT(S): Female age, gravidity, and use of ovulation induction were all independent factors in predicting pregnancy after IUI. The average total motile sperm count in the ejaculate was also an important factor, with a threshold value of 10 million. For IVF, only female age was an important predictor for both clinical and ongoing pregnancy. When the average total motile sperm count was under 10 million, IVF with ICSI was more cost-effective than IUI in our clinic. CONCLUSION(S): An average total motile sperm count of 10 million may be a useful threshold value for decisions about treating a couple with IUI or IVF.

Adult↗
PubMed2001

The use of AEDs by police officers in the City of London. Automated external defibrillators.

The Guidelines 2000 for cardiopulmonary resuscitation recommend shock delivery to victims in ventricular fibrillation within 5 min of call receipt by the Emergency Medical Services. In an effort to achieve this goal, in some parts of the United States, police officers have been trained to use automated external defibrillators (AEDs). We undertook a 3-year pilot evaluation of the use of AEDs by City of London police (CPOL) officers. Over a period of 3 years, 147 CPOL officers were trained in the use of an AED. Four AEDs were placed on rapid response vehicles covering the City of London. An overall call-response interval target was set at 8 min. The CPOL attended 1103 (90%) of the total of 1232 calls to which they were summoned. The mean interval between the first call received and arrival of the CPOL on scene was 8.9+/-4.0 min. The CPOL applied AEDs to 25 victims, 13 of whom were initially in ventricular fibrillation; at least one shock was delivered to all 13. The interval between call reception and delivery of the first shock was 5.5+/-2.5 min. The mean interval between switching on the AED and delivery of the first shock was 24+/-12 s. Two (15%) of these victims survived to hospital discharge. This study has confirmed the feasibility of training police officers in the UK to use AEDs as first responders. The call received to arrival on scene interval should be reduced by improvements in communication between LAS and CPOL.

Adolescent↗