Search PubMed⌕ Search

Biomedical subjects

A L James

Publications and source records attributed to A L James.

At least 37 records · Page 2Linked to original sources
PubMed2000

Alizarin-beta-D-galactoside: a new substrate for the detection of bacterial beta-galactosidase.

We describe the synthesis of a new substrate for the detection of bacterial beta-galactosidase. This substrate, alizarin-beta-D-galactoside, is readily hydrolysed to release alizarin which complexes with various metal ions to form brightly coloured chelates. A total of 367 strains of Gram-negative bacteria were examined for their ability to hydrolyse three chromogenic substrates: alizarin-beta-D-galactoside (Aliz-gal), cyclohexenoesculetin-beta-D-galactoside (CHE-gal) and 5-bromo-4-chloro-3-indolyl-beta-D-galactoside (X-gal). A total of 182 strains (49.6%) were found to hydrolyse at least one of the three substrates. All of these 182 strains (100%) hydrolysed Aliz-gal whereas only 170 (93.4%) and 173 (95.1%) hydrolysed CHE-gal and X-gal, respectively. We conclude that alizarin-beta-D-galactoside is a highly sensitive substrate for the demonstration of beta-galactosidase.

Anthraquinones↗
PubMed2000

Evaluation of p-naphtholbenzein-beta-D-galactoside as a substrate for bacterial beta-galactosidase.

We describe the synthesis of a new substrate for the detection of beta-galactosidase and evaluate its performance in comparison with 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal) and cyclohexenoesculetinbeta-D-galactoside (CHE-Gal). Of 206 Enterobacteriaceae strains able to hydrolyze X-Gal, 194 (94.2%) hydrolyzed CHE-Gal and 192 (93.2%) hydrolyzed p-naphtholbenzein-beta-D-galactoside (PNB-Gal). We conclude that PNB-Gal is an effective substrate for the detection of beta-galactosidase.

Chromogenic Compounds↗
PubMed2000

The airway longitudinal elastic fiber network and mucosal folding in patients with asthma.

A submucosal network of elastic fibers in a collagen and myofibroblast matrix form discrete longitudinal bundles (LB) in the bronchial tree. The LB may affect airway function by altering the mechanical properties of the airway wall or by changing the folding behavior of the airway mucosa. The area and number of LB were quantified from 12 cases each of fatal asthma (FA), nonfatal asthma (NF), and nonasthmatic (NA) control cases on elastic-trichrome stained airways. The effects of group, sex, age, and smoking were examined using multiple linear regression. The area fraction of LB increased (p < 0.05) approximately twofold in cases of FA compared with NA control cases in both large and small airways. The areas of LB were increased in smokers, older subjects, and men (p < 0.05). The number of mucosal folds was related to the number of longitudinal bundles in asthmatics and nonasthmatics and was not different between groups. Collagen and myofibroblasts were increased (p < 0.05) in LB of FA and NF cases compared with NA control cases. The increased size and altered composition of LB in asthma may influence airway function; however, excessive airway narrowing in asthma is not due to altered numbers of mucosal folds.

Adult↗
PubMed2000

Pulmonary vascular congestion selectively potentiates airway responsiveness in piglets.

The influence of pulmonary vascular congestion on the response of the airways and lung tissue to low doses of inhaled methacholine (MCh) was studied by inflating a balloon catheter in the left atrium of the heart in six piglets, with an additional five piglets serving as control animals. Congestion alone resulted in small increased in baseline airway (Raw) (14.6 +/- 3.7%) and tissue (Rti) resistance (8. 1 +/- 6.5%). Low-dose inhaled MCh (0.3 mg/ml) increased Raw and Rti in the control group by 10.8 +/- 10.3% and 42.2 +/- 29.5%, respectively. The increase in Raw with MCh in the presence of vascular engorgement was significantly greater (67.8 +/- 18.9%) but the increase in Rti (38.1 +/- 13.2%) was similar to that seen in the control group. Morphometric measurements were performed on transverse sections of large and small airways from nine additional piglets (three congested only, three MCh only, and three congestion plus MCh). The thickness of the inner airway wall was similar in all groups. Compared with MCh only piglets, the thickness of the outer airway wall (between the outer border of the smooth muscle and the surrounding lung parenchyma) was increased (p < 0.05) in engorged only and engorged plus MCh piglets. Compared with MCh only and engorgement only, the amount of airway smooth muscle shortening was greater (p < 0.05) in all airway size groups in piglets that underwent engorgement plus MCh challenge. The results of this study demonstrate that pulmonary vascular engorgement, induced by increased left atrial pressure, selectively enhances the airway, but not the parenchymal, response to inhaled MCh. These changes are associated with increased thickness of the outer airway wall in response to vascular congestion, suggesting that uncoupling of the mechanical interdependence between the airway smooth muscle and the lung parenchyma may have occurred. Mechanical uncoupling may reduce the load opposing smooth muscle shortening resulting in increased airway narrowing in response to low doses of inhaled methacholine.

Animals↗
PubMed2000

Independent inheritance of serum immunoglobulin E concentrations and airway responsiveness.

Elevated serum Immunoglobulin E (IgE) levels and increased airway responsiveness (AR) are correlated traits that are characteristic of asthma. It is not known to what extent these traits arise from distinct or shared genetic determinants. We investigated the genetic and environmental components of variance of serum total and specific IgE levels and AR in an Australian population-based sample of 232 Caucasian nuclear families. The inter-relationships of the genetic determinants of these traits were also investigated. Log(e) total serum IgE levels had a narrow-sense heritability (h(2)(N)) of 47.3% (SE = 10.0%). Specific serum IgE levels against house dust mite and timothy grass, measured as a RAST Index, ad a h(2)(N) of 33.8% (SE = 7.3%). AR, quantified by the log(e) dose-response slope to methacholine (DRS), had a h(2)(N) of 30.0% (SE = 12.3%). Extended modeling demonstrated an approximate 70% overlap in the genetic determinants of total and specific serum IgE levels. The genetic determinants of serum IgE levels and AR exhibited less than 30% sharing. These data are consistent with the existence of multiple genetic determinants of the pathophysiologic traits associated with asthma, and suggest that AR is genetically distinct from atopy. These results have implications for gene discovery programs.

Adolescent↗
PubMed1999

Lung function, respiratory symptoms, and mortality: results from the Busselton Health Study.

PURPOSE: This study examines the association between lung function [percentage predicted FEV, (forced expiratory volume in 1 s)] and respiratory symptoms (asthma, bronchitis, wheeze, dyspnea) and mortality from all causes; coronary heart disease, stroke, cancer, and respiratory disease in a cohort of 2,100 men and 2,177 women in the Busselton Health Study followed for 20-26 years for mortality. METHODS: A total of 840 men and 637 women died during the follow-up period, and Cox proportional hazards regression was used to assess the relationships between risk factors and mortality. RESULTS: Lung function was significantly and independently predictive of mortality from all causes, coronary heart disease, cancer, and respiratory disease in both men and women, and of mortality from stroke in women. There was evidence that, among men, the association was stronger in current and former smokers as compared to those who never smoked. After adjustment for age, smoking, lung function, coronary heart disease, blood pressure, treatment for hypertension, total cholesterol, body mass index, and alcohol consumption, dyspnea was significantly related to total mortality in men and women and to respiratory disease mortality in men, and asthma was significantly related to respiratory disease mortality in women. CONCLUSIONS: Lung function is associated with mortality from many diseases independent of smoking and respiratory symptoms. Although most respiratory symptoms are associated with smoking and lung function, after controlling for smoking and lung function, only dyspnea is associated with mortality from nonrespiratory causes.

Adult↗
PubMed1999

Associations between white blood cell count, lung function, respiratory illness and mortality: the Busselton Health Study.

An independent association between reduced levels of lung function and increased mortality from nonrespiratory causes has been observed in a number of studies. Since the total white blood cell count (WBC) has been related to both death from coronary heart disease and to levels of lung function, the relationship between these parameters was examined in subjects from the Busselton Health Surveys. Questionnaires regarding respiratory and cardiac illness and smoking habits were administered and total WBC, forced expiratory volume in one second (FEV1) and forced vital capacity measured in 2,105 males and 2,186 females at their initial attendance at a Busselton Health Survey in 1969, 1972 or 1975. Mortality follow-up to 1995 was completed. Multiple linear regression showed that smoking, increasing age, reduced FEV1 (% predicted) and a history of bronchitis were associated with increased WBC. Reduction of FEV1 (% pred) by 20%, a history of dyspnoea and an increase in WBC of 1,300 cells x mL(-1) were predictive of increased mortality from all causes or coronary heart disease by approximately 20, 100 and 10% respectively, independent of smoking. Removing WBC from the regression model did not significantly change the relationship between FEV1 and mortality. The study shows that the white blood cell count, forced expiratory volume in one second and dyspnoea are independently related to mortality in both males and females and that the effect of forced expiratory volume in one second on mortality is not explained by the white blood cell count.

Adult↗
PubMed1998

Detection of carboxypeptidases as taxonomic markers for gram-negative bacteria.

The use of seven benzoyl-L-amino acids for the detection of carboxypeptidase activities in strains of Gram-negative aerobic and facultatively anaerobic bacteria is reported. A simple overnight assay was designed using ninhydrin for the demonstration of the amino acid released by hydrolysis. Detection of carboxypeptidase activity was shown to have some taxonomic relevance within the Enterobacteriaceae; it was also useful for differentiation within the genus Acinetobacter and for distinction between Pseudomonas aeruginosa and Pseudomonas fluorescens.

Amino Acids↗
PubMed1998

Relationship between difficult tracheal intubation and obstructive sleep apnoea.

The upper airway abnormalities predisposing to difficult tracheal intubation may also predispose to obstructive sleep apnoea (OSA). The potential association is important as both conditions increase perioperative risk and patients with a trachea that is difficult to intubate may need assessment for OSA. We determined if patients with difficult intubation are at greater risk of OSA and, if so, whether or not they have characteristic clinical or radiographic upper airway changes. We studied 15 patients in whom the trachea was difficult to intubate and 15 control patients. Each was evaluated clinically (Mallampati score, thyromental distance, neck circumference, head extension), polysomnographically (apnoea-hypoponea index (AHI)) and radiographically (lateral cephalometry). AHI was greater in the difficult intubation group (mean 28.4 (SD 31.7)) compared with controls (5.9 (8.9)) (P < 0.02); eight of 15 patients in the difficult intubation group and two of 15 in the control group had an AHI > 10 (P < 0.03). Difficult intubation, but not OSA, was associated (P < 0.05) with a smaller thyromental distance and mandibular length, and greater soft palate length. Both difficult intubation and OSA were associated (P < 0.05) with a greater Mallampati score, anterior mandibular depth, and smaller mandibular and cervical angles. OSA, but not difficult intubation, was associated (P < 0.05) with increased neck circumference, tongue area and craniocervical angle, and decreased head extension, mandibular ramus length and atlantooccipital distance. We conclude that difficult intubation and OSA are related significantly. They share anatomical features which act to reduce the skeletal confines of the tongue. Patients with OSA may compensate, when awake, by increasing craniocervical angulation, which increases the space between the mandible and cervical spine and elongates the tongue and soft tissues of the neck.

Adult↗
PubMed1998

Increased perception of airway narrowing in patients with mild asthma.

To compare the perception of airway narrowing of nonasthmatic subjects with those having wheeze or mild asthma (doctor-diagnosed), the relationship between FEV1 and breathlessness was examined in 123 subjects from a general population sample. Scores for breathlessness, using the Borg scale, were recorded before and after inhaling incremental doses of methacholine to a maximal dose of 196 mcmol or a maximum change in FEV1 of 50%. A history of asthma symptoms, including wheeze in the previous 12 months, and doctor-diagnosed asthma was obtained by questionnaire. At any given level of FEV1 there was wide variation in Borg scores between subjects, however median Borg scores and the mean slope of Borg score on FEVI was greater in the asthmatic subjects or those with wheeze compared with nonasthmatic subjects or those without wheeze. In both nonasthmatic and asthmatic subjects, those with airway hyperresponsiveness had increased maximum symptom scores and maximum changes in FEVI, but similar Borg scores relative to change in FEVI, compared with those without hyperresponsiveness. We conclude that the perception of mild and moderate degrees of airway narrowing varies widely between individuals but is increased in subjects with a history of mild asthma or wheeze in the last 12 months, independently of airway responsiveness.

Adult↗
PubMed1998

Respiratory symptoms and lung function in aborigines from tropical Western Australia.

To estimate the prevalence of respiratory symptoms, bronchial hyperresponsiveness, smoking, and atopy in a population of Australians of Aboriginal descent (AAD), to determine the association of these and other factors with lung function, and to compare levels of lung function of AAD with Australians of European descent (AED) according to age and height, and to explore reasons for their differences, we conducted a study of 96 male (41 of whom were under 18 yr of age) and 111 female (48 of whom were under 18 yr of age) AAD living in a single remote tropical community in 1993. This population provided data on age, height, and lung function. A modified British Medical Research Council (MRC) questionnaire on respiratory symptoms and smoking was administered. FEV1, FVC, height, age, and bronchial responsiveness to inhaled methacholine were measured. Atopic status was assessed by skin prick tests for eight common allergens. Age- and sex-adjusted lung function was similar to that of other AAD groups and lower than in AED. For children, lung function increased less with increasing height in AAD than in AED. Lung function was reduced in adult AAD as compared with adult AED, although it was not possible to determine statistically whether lung function started to decline at an earlier age or declined faster with increasing age in AAD. A history of asthma, smoking, dyspnea, cough, or sputum production; atopic status; and increased bronchial responsiveness were all associated with lower levels of lung function. Differences in lung function between AAD and AED appear to be determined by characteristics that may be inherited, as well as by adverse external influences.

Adolescent↗
PubMed1997

Expanded norms for the Controlled Oral Word Association Test.

The Controlled Oral Word Association Test (COWAT) is a measure of a person's ability to make verbal associations to specified letters (i.e., C, F, and L). This measure is a useful component of a neuropsychological battery as it is able to detect changes in word association fluency often found with various disorders. In order to generate current norms for the elderly and aid in interpreting their performance, the COWAT was administered to a group of community-dwelling elderly persons. Information regarding total numbers of words produced as well as frequency of perseverations, breaking set, using the same word stem, and using a proper noun is provided.

Age Factors↗
PubMed1997

Note: cyclohexenoesculetin-beta-D-glucoside: a new substrate for the detection of bacterial beta-D-glucosidase.

A new substrate for the detection of bacterial beta-D-glucosidase was evaluated as an alternative to aesculin. This substrate, 3,4-cyclohexenoesculetin-7-beta-D-glucoside, was compared with aesculin for the detection of beta-D-glucosidase in 150 enterococci, 40 streptococci, 12 Listeria sp. and 250 strains of Enterobacteriaceae. In the Gram-positive strains tested, aesculin hydrolysis correlated with hydrolysis of 3,4-cyclohexenoesculetin-7-beta-D-glucoside. In the Gram-negative strains the new substrate was hydrolysed by all aesculin-positive strains and also by four strains (10%) of Escherichia coli which gave a negative aesculin reaction. 3,4-Cyclohexenoesculetin-7-beta-D-glucoside was shown to be a reliable alternative to aesculin and was shown to have significant advantages over aesculin when incorporated into solid media. This was due to the non-diffusible end product produced by hydrolysis of 3,4-cyclohexenoesculetin-7-beta-D-glucoside in the presence of iron.

Bacteria↗
PubMed1997

Bronchial blood vessel dimensions in asthma.

The extent to which the bronchial vasculature contributes to airway wall thickening in large and small airways in patients with asthma is unknown. The aim of this study was to quantify the number and the area occupied by blood vessels in the airway submucosa of patients with and without asthma. We used the monoclonal antibody Factor VIII to measure the blood vessels between the airway basement membrane and the outer border of the smooth muscle. In large cartilaginous airways in patients with fatal asthma, the number and area of large blood vessels were increased and the number and area of small blood vessels were decreased, compared with that in patients with nonfatal asthma and control subjects. However, the total number of blood vessels and the total area occupied by blood vessels per square millimeter in the airway submucosa were similar in patients with fatal asthma or nonfatal asthma and in control subjects in all airway size groups. Blood vessels were distended to a mean value of 80% of their estimated maximal area. The increased number of larger vessels in patients with fatal asthma raises the possibility that vascular congestion associated with an acute severe asthma attack may distend blood vessels. The finding of similar numbers of blood vessels per square millimeter of submucosa in control subjects and in patients with asthma suggests that blood vessels increase in number in patients with asthma only in proportion to increased airway wall area. It is unlikely that submucosal vessels could act as capacitance vessels and significantly alter inner airway wall thickness.

Adult↗
PubMed1996

Phenotypic variation in Waardenburg syndrome: mutational heterogeneity, modifier genes or polygenic background?

We have identified 11 mutational changes in the PAX3 gene in patients with type 1 Waardenburg syndrome (WS1) including three in the paired domain, six within or immediately adjacent to the homeodomain and two previously described polymorphic variants in exons 2 and 6. The affected members of one family carried substitutions involving two base pairs separated by one unaltered codon. Two of the deleterious mutations were identical and three others were identical to previously reported mutations. A comparison of clinical findings in families carrying substitutions in the same codon failed to reveal conspicuous similarities. Although subtle mutation-specific effects may well exist, allelic heterogeneity clearly cannot account for within family variation. However, the striking concordance of a pair of monozygotic twins with Waardenburg syndrome (WS) and previous reports of similar pairs indicate that phenotypic variation in WS has a genetic basis. If the genetic effects are mediated by oligogenic epistasis, as studies in the mouse suggest, it may ultimately be possible to predict clinically relevant aspects of the Waardenburg phenotype.

Amino Acid Sequence↗
PubMed1996

Evaluation of cyclohexenoesculetin-beta-D-galactoside and 8-hydroxyquinoline-beta-D-galactoside as substrates for the detection of beta-galactosidase.

We describe the synthesis of two new substrates for the detection of beta-galactosidase and evaluate their performance in comparison with that of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). Of 171 Enterobacteriaceae strains that were able to hydrolyze X-Gal, 166 (97.1%) also hydrolyzed cyclohexenoesculetin-beta-D-galactoside whereas only 96 (56.1%) showed evidence of hydrolysis of 8-hydroxyquinoline-beta-D-galactoside. No false-positive results were observed with either substrate.

Enterobacteriaceae↗
PubMed1995

Fc epsilon RI-beta polymorphism and risk of atopy in a general population sample.

OBJECTIVE: To establish the prevalence of Fc epsilon RI-beta polymorphisms Leu181 and Leu181/Leu183 on chromosome 11q13 in the general population and to examine whether when maternally inherited they confer a risk of atopy. DESIGN: A population based survey for measures of atopy (skin prick test reactions, specific IgE titres, total serum IgE concentration), bronchial hyperresponsiveness, and carriage of Fc epsilon RI-beta Leu181 and Leu181/Leu183. SETTING: The rural coastal town of Busselton, Western Australia. SUBJECTS: 1004 members of 230 two generation families identified through adults aged under 55. RESULTS: Fc epsilon RI-beta Leu181/Leu183 was identified in 45 subjects (4.5%). All 13 children who had inherited the variant maternally were atopic. Six had asthma and nine rhinitis. The odds ratio of a positive skin prick test reaction to house dust mite or grass pollen in these children compared with the other 523 children was 7.37 (95% confidence interval 1.62 to 33.60). The 95% confidence interval for the odds ratio of a positive specific IgE response (radio-allergosorbent test) was 3.00 to infinity, and the odds ratio for bronchial hyperresponsiveness was 3.70 (1.21 to 11.60). By contrast, the eight children who had derived the variant paternally had negative skin prick and radioallergosorbent test results and did not have increased bronchial responsiveness. CONCLUSION: Fc epsilon RI"' beta Leu181/Leu183 when inherited maternally identifies a genetic risk factor for atopy and bronchial hyperresponsiveness.

Adolescent↗