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Biomedical subjects

A Bush

Publications and source records attributed to A Bush.

At least 199 records · Page 11Linked to original sources
PubMed1994

Review--neonatal bronchoscopy.

Neonatologists are increasingly exploring the airways with rigid and flexible bronchoscopes. Each instrument has particular advantages; the rigid endoscope mainly for therapy, including balloon dilatation of acquired strictures, and the fibrescope mainly for inspection of the airway for diagnostic purposes. Before using either technique, it is essential to ensure that the information will be really useful and cannot be obtained using less invasive methods.

Bronchoscopy↗
PubMed1994

Activated peripheral blood CD4 and CD8 T-lymphocytes in child asthma: correlation with eosinophilia and disease severity.

There now exists compelling evidence of a role for cell-mediated immunity in the pathogenesis of adult asthma, but little information is available as to what extent this process participates in the pathogenesis of childhood asthma. We hypothesised that asthma in children is associated with the activation of T-lymphocytes whose products regulate, at least in part, the mobilisation and recruitment of eosinophils and thereby disease severity. Our aims, therefore, were to compare the expression of activation markers, including CD45 isoforms, on peripheral blood T-lymphocytes from asthmatic and non-asthmatic, allergic control children matched for age and atopic status, and to attempt to correlate the percentages of activated T-lymphocytes in the asthmatics with the numbers of peripheral blood eosinophils and with disease severity. Seventeen children with moderate to severe chronic asthma were compared with 8 non-asthmatic, allergic children matched for age and atopic status. Expression of the activation markers CD25, HLA-DR and VLA-1 and the CD45 isoforms CD45RA and CD45RO on peripheral blood CD4 and CD8 T-lymphocytes was measured using dual fluorescence flow cytometry. Peripheral blood eosinophils were measured using an automated laser cytometer. Asthma severity was assessed by a symptom score, spirometry and measurement of histamine PC20. The absolute numbers of eosinophils in the peripheral blood of the asthmatics were elevated as compared to the non-asthmatic, allergic controls (p < 0.01), whereas the absolute numbers of both CD4+ and CD8+ T-lymphocytes were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Rise in total IgE as an indicator of allergic bronchopulmonary aspergillosis in cystic fibrosis.

BACKGROUND: Allergic bronchopulmonary aspergillosis is a serious complication of cystic fibrosis and may be difficult to diagnose. The aim of this study was to define the usefulness of measuring total IgE compared with other major criteria in the diagnosis of allergic bronchopulmonary aspergillosis in children with cystic fibrosis. METHODS: A retrospective analysis was carried out of the case records of 160 children attending a tertiary referral paediatric cystic fibrosis clinic. RESULTS: Sixteen children had a total IgE level above 500 IU/ml. Eleven children had six or more other major criteria and were considered to have allergic bronchopulmonary aspergillosis. These 11 children had a fourfold rise in IgE in association with clinical deterioration. A further child had a fourfold rise in IgE to 341 IU/l, and was also thought to have allergic bronchopulmonary aspergillosis. Eleven had a fall in IgE with successful treatment; one patient died with uncontrolled disease. Only one of these 12 children had negative precipitins to Aspergillus fumigatus. The five children with a raised IgE not thought to have bronchopulmonary aspergillosis had four or fewer major criteria and were not treated; none had positive precipitins. CONCLUSIONS: A fourfold rise in total IgE, particularly to above 500 IU/ml, is strongly suggestive of the diagnosis of allergic bronchopulmonary aspergillosis in children with cystic fibrosis. The measurement of total IgE has the merit of being simple to perform and objective. Positive aspergillus precipitins provide useful confirmatory evidence. These two criteria, taken in conjunction with clinical deterioration and new radiological shadowing, allow simplification of the diagnosis of allergic bronchopulmonary aspergillosis in cystic fibrosis.

Adolescent↗
PubMed1994

Assessment of hyperinflation in children with cystic fibrosis.

BACKGROUND: Radiological estimates of hyperinflation are used in several clinical and radiographic scoring systems for cystic fibrosis, but it is not known if these estimates of hyperinflation are related to measured total lung capacity. METHODS: Comparison was made of independent clinical estimates of hyperinflation from chest radiographs with objective plethysmographic and radiographic measurements of total lung capacity in 25 children with cystic fibrosis. RESULTS: There was good agreement between plethysmographic and radiographic measurements. Clinical estimation correctly predicted the extremes of hyperinflation, but grading was no more than 50% accurate in all other groups. CONCLUSION: The degree of hyperinflation cannot be estimated by inspecting chest radiographs in many children with cystic fibrosis. This does not invalidate the scoring systems, but suggests that a better term than "hyperinflation" should be sought.

Adolescent↗
PubMed1993

Conservative management of foetal lung lesions.

Routine antenatal ultrasound screening has identified a variety of malformations which may present as hyperechogenic or cystic lung lesions. Knowledge of the natural history of these lesions in utero and after birth is incomplete, and an exact diagnosis is not always possible. Despite this, an increasing number of interventions and terminations of pregnancy are being undertaken. We advocate a more conservative approach in the management of these lesions. We describe three cases and review the current literature to demonstrate the uncertain natural history of these lesions, the diagnostic difficulties, and some of the medical and ethical problems of intervention.

Adult↗
PubMed1993

New associations of primary ciliary dyskinesia syndrome.

Ten of 32 patients with primary ciliary dyskinesia syndrome (PCDS) also had other conditions. Five esophageal problems, 4 congenital heart disease, 2 scoliosis, and 4 miscellaneous and probably coincidental conditions were discovered. Additionally, a patient in this series, who has a normal heart, had a brother who died after surgery for complex congenital heart disease. In retrospect, he too probably had PCDS. The association of severe esophageal and cardiac disease with primary ciliary dyskinesia has not been described before. The diagnosis of PCDS may carry more implications than previously recognized.

Adolescent↗
PubMed1993

Genetic heterogeneity of gene defects responsible for familial Alzheimer disease.

Inherited Alzheimer's disease is a genetically heterogeneous disorder that involves gene defects on at least five chromosomal loci. Three of these loci have been found by genetic linkage studies to reside on chromosomes 21, 19, and 14. On chromosomes 21, the gene encoding the precursor protein of Alzheimer-associated amyloid (APP) has been shown to contain several mutations in exons 16 and 17 which account for roughly 2-3% of familial Alzheimer's disease (FAD). The other loci include what appears to be a susceptibility gene on chromosome 19 associated with late-onset (> 65 years) FAD, and a major early-onset FAD gene defect on the long arm of chromosome 14. In other early- and late-onset FAD kindreds, the gene defects involved do not appear to be linked to any of these three loci, indicating the existence of additional and as of yet unlocalized FAD genes. This review provides a historical perspective of the search for FAD gene defects and summarizes the progress made in world-wide attempts to isolate and characterize the genes responsible for this disorder.

Alzheimer Disease↗
PubMed1993

Reproducibility of random amplified polymorphic DNA (RAPD) analysis among laboratories.

Random amplified polymorphic DNA (RAPD) analysis appears to offer a cost- and time-effective alternative to restriction fragment-length polymorphism (RFLP) analysis. However, concerns about the ability to compare RAPD results from one laboratory to another have not been addressed effectively. DNA fragments that were amplified by five primers and shown to be reproducibly polymorphic between two oat cultivars (within the Ottawa laboratory) were tested in six other laboratories in North America. Four of the six participants amplified very few or no fragments using the Ottawa protocol. These same participants were able to generate a considerable number of amplified fragments by using their own protocols. The reproducibility of results among laboratories was affected by two factors. First, different laboratories amplified different size ranges of DNA fragments, and, consequently, small and large polymorphic fragments were not always reproduced. Second, although reproducible results were obtained with four of the primers, reproducible results were not obtained with the fifth primer, using the same reaction conditions. It is suggested that if the overall temperature profiles (especially the annealing temperature) inside the tubes are identical among the laboratories, then RAPD fragments are likely to be reproducible.

Base Sequence↗
PubMed1993

The relationship of insulin insensitivity to menstrual pattern in women with hyperandrogenism and polycystic ovaries.

OBJECTIVE: Insulin insensitivity is a recognized feature of polycystic ovary syndrome (PCOS) but previous studies have suggested that circulating insulin concentrations are normal in hyperandrogenaemic women with regular cycles. The aim of this study was to examine the relationship between insulin sensitivity and menstrual pattern in women with PCO. DESIGN: A cross-sectional study of insulin sensitivity in a cohort of PCO subjects with oligomenorrhoea compared to women with PCO and regular menstrual cycles and a group of normal control subjects. SUBJECTS: Seventy-two women with polycystic ovaries on ultrasonography were studied. PCO subjects had clinical and/or biochemical evidence of hyperandrogenism; 53 had oligo/amenorrhoea (olig) and 19 had regular menses (reg). Results were compared with 31 control subjects. The groups were matched for age, weight and ethnic origin. METHODS: Glucose and insulin responses to 75 g oral glucose were measured. Insulin sensitivity was assessed by the decline in plasma glucose following intravenous insulin (0.05 U/kg). RESULTS: Glucose area (mean +/- SEM) after oral glucose was increased slightly in both PCO groups compared with controls (olig 37.6 +/- 1.4, reg 36.0 +/- 1.8, control 33.7 +/- 0.9 mmol/l h, both P < 0.01). Insulin area median (interquartile range) in response to glucose was significantly greater in the oligomenorrhoeic group (346 (239-734) mU/l h), compared with both PCO with regular cycles (246 (148-355), P < 0.01) and controls (221 (147-277), P < 0.01). Insulin sensitivity was reduced (P < 0.01) in the oligomenorrhoeic group (147 +/- 9.2 mumol/l min) compared to controls (185 +/- 7.4) but was normal in PCO with regular cycles (182 +/- 12.5). Insulin sensitivity did not correlate significantly with plasma testosterone or with SHBG levels, but plasma insulin concentrations correlated negatively with SHBG levels (fasting insulin vs SHBG, r = -0.47, P < 0.01; insulin area vs SHBG, r = -0.41, P < 0.01). CONCLUSIONS: Insulin insensitivity in polycystic ovary syndrome occurs when there is oligo/amenorrhoea but not when the menstrual cycle is regular. This is consistent with PCO and insulin insensitivity being separate abnormalities which when combined are associated with anovulation.

Adult↗
PubMed1993

Lung function in white children aged 4 to 19 years: I--Spirometry.

OBJECTIVE: A study was performed to produce reference standards for spirometric lung function in white children and to calculate standard deviation scores adjusted for gender and pubertal stage. METHODS: A cross sectional study was made of 772 white children aged 4.6 to 18.8 years (455 male) tested on an OHIO 840 spirometer and assessed anthropometrically and pubertally. RESULTS: Before puberty there was a linear increase in all lung function measurements with height. During puberty a sudden increase occurred, but subsequently the relationship was again linear. No simple single equation described this pattern. Advanced puberty in younger children conferred a respiratory advantage, whilst delayed puberty resulted in the converse. Girls had poorer volumes per unit height, but young girls had superior airflow/unit lung volume. In both sexes lung volumes and flows bore a constant relationship to external thoracic dimensions. CONCLUSIONS: Puberty has a dramatic effect on lung function. Regression equations for predicted values of lung function measurements and for calculation of standard deviation scores are given (with pubertal correction factors) for each gender.

Adolescent↗
PubMed1993

Lung function in white children aged 4 to 19 years: II--Single breath analysis and plethysmography.

OBJECTIVE: A study was performed to determine reference ranges for whole body plethysmographic gas volumes and single breath gas transfer in healthy prepubertal and pubertal schoolchildren. METHODS: The study was performed in 772 white London schoolchildren (455 male) who were clinically examined, assessed auxologically and, in 63% of cases, pubertally staged. Regression equations for the calculation of standard deviation scores were derived. RESULTS: Male lung function variables showed a discontinuous pattern of increase with standing height. Linear increases until puberty were followed by a sudden pubertal rise and a further increase with height which was more marked than before puberty. Correction for varying thoracic dimensions eliminated these changes. In females a smoother curvilinear relationship was observed with no correction possible for thoracic size. CONCLUSIONS: Male puberty leads to profound changes in pulmonary function mostly related to thoracic size, an effect not observed in females.

Adolescent↗