Search PubMed⌕ Search

Biomedical subjects

J Britton

Publications and source records attributed to J Britton.

At least 109 records · Page 6Linked to original sources
PubMed1998

Survival in patients with cryptogenic fibrosing alveolitis: a population-based cohort study.

STUDY OBJECTIVES: To determine the median survival of patients with cryptogenic fibrosing alveolitis, in comparison to that expected of individuals of the same age and sex from the general population. To estimate the effect of survival bias incurred by studying both incident and prevalent cases. To identify factors associated with survival. DESIGN: Cohort study. SETTING: Nine hospitals from the Trent Region of England. PATIENTS: Two hundred forty-four cases of cryptogenic fibrosing alveolitis: 168 patients were alive on day 1 of the study (prevalent cases), and 76 patients had newly diagnosed conditions over a prospective 18-month period of patient recruitment (incident cases). MEASUREMENTS: Age, sex, date of diagnosis, lung function at presentation, and details of treatment prescribed were extracted from hospital clinical records. Data on lifetime smoking habits were collected by postal questionnaire. Vital status was established from the general practitioner. The expected survival of each case was extracted from the English life tables. RESULTS: Median survival for incident cases was 2.9 years and for prevalent cases 9 years, compared to expected values of 10 and 13 years, respectively. Incident cases had significantly worse survival than prevalent cases, even after adjustment for the effects of age, sex, smoking history, lung function at presentation, and treatment (hazard ratio, 4.53 [95% confidence interval, 2.71 to 7.56]; p<0.001). Lower FVC at presentation and the use of corticosteroid treatment were both associated with worse survival. CONCLUSIONS: The inclusion of prevalent cases leads to significant overestimation of the median survival for patients with cryptogenic fibrosing alveolitis. In newly diagnosed cases of cryptogenic fibrosing alveolitis, median survival is only 2.9 years, and expected life span is reduced by approximately 7 years.

Adrenal Cortex Hormones↗
PubMed1997

Investigation into the increase in hay fever and eczema at age 16 observed between the 1958 and 1970 British birth cohorts.

OBJECTIVE: To investigate whether changes in certain perinatal and social factors explain the increased prevalence of hay fever and eczema among British adolescents between 1974 and 1986. DESIGN: Two prospective birth cohort studies. SETTING: England, Wales, and Scotland. SUBJECTS: 11,195 children born 3-9 March 1958 and 9387 born 5-11 April 1970. MAIN OUTCOME MEASURES: Parental reports of eczematous rashes and of hay fever or allergic rhinitis in the previous 12 months at age 16. RESULTS: The prevalence of the conditions over the 12 month period increased between 1974 and 1986 from 3.1% to 6.4% (prevalence ratio 2.04 (95% confidence interval 1.79 to 2.32)) for eczema and from 12.0% to 23.3% (prevalence ratio 1.93 (1.82 to 2.06)) for hay fever. Both conditions were more commonly reported among children of higher birth order and those who were breast fed for longer than 1 month. Eczema was more commonly reported among girls and hay fever among boys. The prevalence of hay fever decreased sharply between social classes I and V, increased with maternal age up to the early 30s, and was lower in children whose mothers smoked during pregnancy. Neither condition varied significantly with birth weight. When adjusted for these factors, the relative odds of hay fever (1986 v 1974) increased from 2.23 (2.05 to 2.43) to 2.40 (2.19 to 2.63). Similarly, the relative odds of eczema rose from 2.02 (1.73 to 2.36) to 2.14 (1.81 to 2.52). CONCLUSIONS: Taken together, changes between cohorts in sex, birth weight, birth order, maternal age, breast feeding, maternal smoking during pregnancy, and father's social class at birth did not seem to explain any of the observed rise in the prevalence of hay fever and eczema. However, correlates of these factors which have changed over time may still underlie recent increases in allergic disease.

Adolescent↗
PubMed1997

Prevalence of wheeze and asthma and relation to atopy in urban and rural Ethiopia.

BACKGROUND: Asthma and allergy in developing countries may be associated with adoption of an urbanised "western" lifestyle. We compared the rates of asthma symptoms and atopy in urban populations in Jimma, southwest Ethiopia, at an early stage of economic development with those among the population of remote, rural, subsistence areas, and assessed the potential role of environmental aetiological factors leading to the differences. METHODS: Information on wheeze of 12 months' duration, diagnosed asthma, and cough for 3 months of the year was gathered by questionnaire in random household samples of 9844 people from urban Jimma and of 3032 from rural areas. Atopy was defined by allergen skin-test response to Dermatophagoides pteronyssinus and mixed threshings measured in a one-in-four subsample of those aged 5 years and older from both groups. FINDINGS: All respiratory symptoms were rare in children and were significantly less common overall in the rural than in urban group (wheeze odds ratio 0.31 [95% CI 0.22-0.43], p < 0.0001). Asthma was reported by 351 (3.6%) of the urban group, with a median reported duration of 8.5 years (IQR 4-17 years) that was unrelated to age. Atopy was a strong risk factor for asthma in urban Jimma. In the rural areas, skin sensitivity to mixed threshings was only slightly less common than in urban Jimma (0.67 [0.40-1.12], p = 0.13), whereas sensitivity to D pteronyssinus was significantly more common (3.24 [2.40-4.38], p < 0.0001), and since none of the 119 atopic individuals in the rural area reported wheeze or asthma, atopy was possibly associated with a reduction in the risk of disease among this group. Wheeze or D pteronyssinus sensitivity were positively associated with housing style, bedding materials, and use of malathion insecticide, but no single factor accounted for the urban-rural differences. INTERPRETATION: Wheeze and asthma are especially rare in rural subsistence areas, and atopy may be associated with a reduced prevalence of these symptoms in this environment. In urban Jimma, self-reported asthma seemed to emerge as a clinical problem about 10 years before our study began, which is consistent with an effect of new environmental exposures. The factor or factors leading to the increase in asthma and allergy have not been identified, although exposures related to general changes in the domestic environment are likely to be involved.

Adolescent↗
PubMed1997

Craniopharyngioma: improving outcome by early recognition and treatment of acute complications.

PURPOSE: To assess the frequency, mode of presentation, treatment, and outcome of acute complications in patients with craniopharyngioma around the time of radiotherapy. METHODS AND MATERIALS: A review was made of 188 patients with craniopharyngioma treated with conservative surgery and external beam radiotherapy at the Royal Marsden Hospital between 1950 and 1992. RESULTS: Twenty six (14%) (95% confidence interval: 9-19%) patients with craniopharyngioma developed acute deterioration immediately before, during and 2 months after radiotherapy with visual deterioration (19 patients), hydrocephalus (7 patients), and global deficit (7 patients). Cystic enlargement with or without hydrocephalus was the most common cause of deterioration. No patient or disease characteristics were predictive of deterioration on univariate or multivariate analysis. Eighteen patients had surgical intervention at the time of deterioration and survived the immediate period. Six of seven patients who did not have surgical intervention died. All patients who survived the postcomplication period completed the full course of external beam radiotherapy. The 10-year progression-free survival of 162 patients without deterioration was 86%, and of 18 patients with acute deterioration who recovered after surgery, 77%. CONCLUSION: Patients with craniopharyngioma develop acute deterioration around the time of radiotherapy owing to cystic enlargement and/or hydrocephalus which does not represent tumor progression. Early recognition and appropriate surgical treatment followed by conventional full-dose radiotherapy are associated with good long-term outcome.

Adolescent↗
PubMed1997

Management of severe pancreatitis in renal transplant recipients.

OBJECTIVE: The authors determine if any aspects of the treatment of renal transplant patients with pancreatitis were of particular benefit with regard to graft and patient survival. BACKGROUND: The incidence of pancreatitis in renal transplant patients is low (1%-2%), but the mortality of the disease approaches 100%. Although several descriptive reports have been published, there is no consensus-regarding management. METHODS: The authors conduct a retrospective chart review. RESULTS: Twenty-one patients were identified with posttransplant pancreatitis (1.3% incidence). The cause of pancreatitis was presumed to be maintenance immunosuppression in all cases. Patients were classified by dynamic computed tomography (CT) scans having 1) mild/edematous disease (4 patients), 2) localized abscess or pseudocyst (6 patients), or 3) severe disease (11 patients). Patients with mild/edematous pancreatitis did well with medical management. The six patients with localized abscess or pseudocyst were successfully treated with standard operative intervention. Of the 11 patients with severe disease, 6 had several days of intensive medical management before operation, and all died. The other five patients underwent early operative intervention based principally on CT scan findings, and all survived. The latter group had multiple operations and four of five had functioning renal allografts at discharge. CONCLUSION: The severity of pancreatitis in the posttranplant patients may be difficult to assess by clinical criteria. Dynamic CT scanning is, therefore, essential in defining the extent of disease. Early, and perhaps repeated, operations may be lifesaving in those patients having CT scan findings of severe pancreatitis.

Adult↗
PubMed1997

Investigation of the effect of short-term change in dietary magnesium intake in asthma.

Epidemiological evidence suggests that a low dietary intake of magnesium is associated with impaired lung function, bronchial hyperreactivity and wheezing. This study was designed to investigate whether short-term alterations of dietary magnesium intake have an effect on the clinical control of asthma. In a randomized, double-blind, placebo-controlled, cross-over study, 17 asthmatic subjects adhered to a low magnesium diet for two periods of 3 weeks, preceded and separated by a 1 week run-in/wash-out, in which they took either placebo or magnesium (400 mg x day(-1)) tablet supplementation. Forced expiratory volume in one second (FEV1) and the provocative dose of methacholine required to cause a 20% fall in FEV1 from baseline (PD20,FEV1) were measured at the beginning and end of each treatment period, and variation in peak expiratory flow (PEF) rate, bronchodilator use and symptom scores recorded throughout. Asthma symptom scores were significantly lower during the magnesium treatment period, the median (95% confidence interval) difference from placebo being 3.8 (0.5-7.0) symptom points per 7 days (p=0.02). However, there was no significant improvement in FEV1, PD20,FEV1, log amplitude percentage mean PEF variation or bronchodilator use during magnesium supplementation. A high magnesium intake was associated with improvement in symptom scores, though not in objective measures of airflow or airway reactivity, in these stable asthmatic subjects.

Adult↗
PubMed1997

Alpha1-antitrypsin phenotypes in patients with cryptogenic fibrosing alveolitis: a case-control study.

Cryptogenic fibrosing alveolitis (CFA) is an interstitial lung disease, which by definition is of unknown aetiology. Recent evidence has suggested that smoking and occupational exposure to dusts may be environmental risk factors for the disease, but there has been little research into potential host risk factors. One previous study has suggested that the prevalence of abnormal alpha1-antitrypsin phenotypes may be increased in patients with CFA. Since alpha1-antitrypsin is important in regulating inflammation within the lung in response to environmental exposures, such abnormalities may be of aetiological importance in this disease. We have compared the alpha1-antitrypsin phenotypes of 189 patients with CFA with 189 age-, sex-, and community-matched controls. This sample size was sufficient to provide more than 95% power to detect an odds ratio (OR) of 2.5. Alpha1-antitrypsin phenotype was established by isoelectric focusing, and the prevalence of abnormal phenotypes in cases and controls was compared by conditional logistic regression. Personal smoking histories were obtained by postal questionnaire. The prevalence of abnormal alpha1-antitrypsin phenotypes was similar in cases and controls (12.7 versus 15.3%; OR 0.88; 95% confidence interval 0.49-1.57; p=0.66). No interaction was found between the presence of abnormal alpha1-antitrypsin phenotypes and a history of smoking. We conclude that cryptogenic fibrosing alveolitis is not associated with abnormal alpha1-antitrypsin phenotypes.

Adult↗
PubMed1997

Studies of the effects of inhaled magnesium on airway reactivity to histamine and adenosine monophosphate in asthmatic subjects.

BACKGROUND: Magnesium is a cation with smooth muscle relaxant and anti-inflammatory effects and may therefore have a role in the therapy of asthma. Several studies have investigated the effects of intravenous magnesium in acute or stable asthma, but little is known about the effects of inhaled magnesium. OBJECTIVE: To measure the effects of a single inhaled nebulized dose of 180 mg magnesium sulphate on airway reactivity to a direct-acting bronchoconstrictor (histamine) and an indirect-acting bronchoconstrictor (adenosine monophosphate [AMP]) in asthmatic subjects. METHODS: Two separate randomized, double-blind, placebo-controlled crossover studies, each involving 10 asthmatic subjects. In the histamine study, airway reactivity to histamine was measured and lung function allowed to recover spontaneously over 50 min before administering nebulized magnesium sulphate or saline placebo. Airway reactivity to histamine was then measured at 5 and 50 min. In the AMP study, a single measurement of airway reactivity was made 5 min after magnesium or placebo. RESULTS: In the histamine study, the provocative dose required to reduce FEV1 by 20% (PD20FEV1) was significantly lower after magnesium than after placebo, by a mean (95% CI) of 1.02 (0.22-1.82) doubling doses at 5 min (P = 0.018), and 1.0 (0.3-1.7) doubling doses at 50 min (P = 0.01). In the AMP study, PD20FEV1 was also significantly lower at 5 min after magnesium than after saline, by 0.64 (0.12-1.16) doubling doses (P = 0.023), though this difference was not statistically significant after adjustment for differences in baseline FEV1 on the two study days. CONCLUSIONS: Inhaled magnesium did not protect against the effects of these direct and indirect bronchoconstrictor stimuli in subjects with asthma, and may have increased airway reactivity to histamine.

Adenosine Monophosphate↗
PubMed1996

Smoke signals.

Explore the source record for details and available documents.

Child↗
PubMed1996

Occupational exposure to metal or wood dust and aetiology of cryptogenic fibrosing alveolitis.

BACKGROUND: We have previously suggested that cryptogenic fibrosing alveolitis (CFA) may be caused by occupational exposures, particularly to metal or wood dust. We have specifically investigated this hypothesis in a case-control study of patients with CFA. METHODS: We obtained lifetime occupational histories by postal questionnaire from 218 patients with CFA and 569 controls matched for age, sex, and community, living in the Trent region of the UK. Information was subsequently verified by telephone interview in 165 cases and 408 controls. Serum IgE, rheumatoid factor, and antinuclear antibodies and skin sensitivity to common allergens were measured in cases and in one matched control for each. FINDINGS: The relative risk of CFA, after adjustment for smoking, was significantly increased in relation to questionnaire-reported exposure to metal dust (odds ratio 1.68 [95% CI 1.07-2.65], p = 0.024) or to wood dust (1.71 [1.01-2.92], p = 0.048). Similar results were obtained with the telephone interview data. Significant exposure-response effects were found for both metal-dust and wood-dust exposure. CFA was also associated with the presence of rheumatoid factor or antinuclear antibodies, but not with positive allergen skin tests or raised IgE concentrations. There was no evidence of interaction between the effects of rheumatoid factor, antinuclear antibodies, positive skin allergen tests, or IgE concentrations and exposure to metal or wood dust. The combined aetiological fraction attributable to exposure to metal or wood dust was of the order of 20%. INTERPRETATION: Occupational exposures to metal or wood dust are independent risk factors for CFA. Avoidance or limitation of these exposures may provide an opportunity to prevent the disease.

Autoantibodies↗
PubMed1996

An economic evaluation of laparoscopic versus open inguinal hernia repair.

BACKGROUND: The rapid and widespread introduction of minimal access surgery has major implications for the National Health Service. It cannot be assumed that replacing an open procedure with a minimal access alternative will be cost-effective. Laparoscopic inguinal hernia repair is a procedure for which the potential economic benefits are particularly unclear. It is currently being adopted in many centres, although limited evidence on its clinical and cost-effectiveness exists. METHODS: This economic comparison of laparoscopic versus open hernia repair was undertaken on data collected on 104 patients undergoing surgery on a day case basis, in the context of a randomized controlled trial. RESULTS: The mean total health service cost of laparoscopic repair was 1074 pounds versus 489 pounds for open repair [mean difference in total health service costs 583 pounds; 95 percent confidence interval (CI) 265 pounds-904 pounds]. This difference was largely accounted for by the difference in theatre costs. Laparoscopic repair remained significantly more expensive for most but not all of the scenarios explored in the sensitivity analysis. The direction of the cost-effectiveness ratio was not sensitive to assumptions about long-term recurrence. Neither was it sensitive to halving the operating time in the laparoscopic arm of the trial. When both operating time and the costs of consumables were reduced, laparoscopic repair remained more expensive, but results for this scenario did not achieve statistical significance on this sample size. CONCLUSIONS: Laparoscopic hernia repair appears an expensive option in most plausible situations. Furthermore, many uncertainties still exist about long-term outcome after the procedure and about the conditions necessary to maximize cost-effectiveness. Large-scale randomized studies to evaluate laparoscopic hernia repair are currently under way to address these issues. We suggest that further evidence is awaited before this technology is further diffused.

Adolescent↗
PubMed1996

Effect of intravenous magnesium sulphate on airway calibre and airway reactivity to histamine in asthmatic subjects.

In a randomized, double-blind, placebo controlled cross-over study we have investigated the effect of intravenous magnesium on airway calibre and airway reactivity to histamine in 20 subjects with mild to moderate asthma. After baseline measurements of forced expiratory volume in one second (FEV1), subjects received 100 ml normal saline with or without 2 g of magnesium sulphate by infusion over 20 min. Measurements of FEV1 were repeated at 5 min intervals throughout the infusion, and the provocative dose of histamine required to drop the FEV1 by 20% from baseline (PD20FEV1) was determined at 20 min. The area under the curve (AUC) in litre minutes for change from baseline in FEV1 between 0 and 20 min was significantly higher on the magnesium study day (mean difference in AUC (95% CI) 1.71 (0.02-3.4), P = 0.049). The increase in FEV1 from baseline with magnesium relative to saline was maximal at 20 min (mean difference (95% CI) 0.13 (0.02-0.23) l, P = 0.01). Log PD20FEV1 to histamine was not significantly different after magnesium and saline (mean difference in log PD20FEV1 (95% CI) 0.04 (-0.19 to 0.27), P = 0.7). We conclude that intravenous magnesium is a weak bronchodilator but does not alter airway reactivity at this dose in stable asthmatic subjects.

Adult↗
PubMed1996

Huntington's disease: a molecular genetic and CT comparison.

Huntington's disease is a progressive neurodegenerative disease in which the molecular abnormality has recently been described. Before the availability of this molecular marker diagnosis depended on clinical findings, supported in some instances by neuroimaging using CT or MRI. The imaging modalities may show atrophy of the heads of caudate nuclei in affected people. An attempt was made to validate these imaging findings using the molecular test as "gold standard." Retrospective analysis of cranial CT in 16 patients with Huntington's disease and 16 age and sex matched controls was performed. There was a highly significant difference in caudate head size (P < 0.00001) between patients with Huntington's disease and control subjects. However, the sensitivity of diagnosis based on radiological examination alone was only 87.5% in this study. Thus the sensitivity of CT is insufficient to justify its routine use in the investigation of suspected Huntington's disease, unless genetic tests are negative and other diagnoses need to be excluded.

Adult↗
PubMed1996

A cross sectional study of the independent effect of occupation on lung function in British coal miners.

BACKGROUND: Chronic bronchitis and emphysema are now recognised complications of occupational exposure to coal dust, and since 1992 compensation has been available for miners with impaired lung function provided that they also have x ray film evidence of pneumoconiosis. However, many miners with heavy exposure to coal dust and impairment of lung function therefore do not qualify for compensation because they do not have simple pneumoconiosis. In the present study attempts were made to determine whether coal mining is an independent risk factor for impairment of lung function in a group of Nottinghamshire miners with no evidence of simple pneumoconiosis, by comparing these men with a group of local controls who were not occupationally exposed. METHOD: Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were obtained on 1286 miners with no evidence of pneumoconiosis on x ray film. Lung function data were also obtained from a random sample of 567 men aged between 40 and 70 living in a district of Nottingham and who had never worked in the mining industry or in any other dusty occupation. Multiple linear regression in SPSS was used to estimate the mean independent effect of mining on FEV1 and FVC after adjustment for age, height, and smoking, in all miners and controls, and in a subgroup of men of 45 and under. In men of 45 and under, the independent effects of mining and smoking on the probability of a deficit of one litre or more from modelled predicted FEV1 values were computed with logistic regression in EGRET. RESULTS: There was a significant mean effect of mining on FEV1 after adjustment for age, height, and smoking of -155 ml (95% confidence interval (95% CI) -74 to -236 ml, P < 0.001), but the size of effect was inversely related to age such that in men of 45 and under the estimated mean effect of mining was -251 ml (95% CI -140 to -361 ml, P < 0.001). In this subgroup of younger men, 4.7% of miners and 0.7% of controls had a deficit of one litre or more from predicted FEV1 values, and in logistic regression, there was a marginally significant independent effect of both smoking (P = 0.05) and mining (P = 0.07) for a deficit of this magnitude. CONCLUSIONS: Occupational exposure to coal dust is associated with a small mean deficit in lung function even in the absence of simple pneumoconiosis, and independently from the effects of smoking. The requirement that miners should have evidence of pneumoconiosis to qualify for compensation for impaired lung function is therefore unjustified.

Adult↗