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J A Halliday

Publications and source records attributed to J A Halliday.

30 records · Page 2Linked to original sources
PubMed1993

Increased wheeze but not bronchial hyperreactivity near power stations.

STUDY OBJECTIVE: In a previous study a higher than expected prevalence of asthma was found in Lake Munmorah, a coastal town near two power stations, compared with another coastal control town. This study aimed to compare atopy, bronchial hyperreactivity, and reported symptoms of asthma in the power station town and a second control area with greater socioeconomic similarity. DESIGN: A cross sectional survey was undertaken. SETTINGS: Lake Munmorah, a coastal town near two power stations, and Dungog, a country town in the Hunter Valley, NSW, Australia. PARTICIPANTS: All children attending kindergarten to year 6 at all schools in the two towns were invited to participate in 1990. The response rates for the questionnaire for reported symptoms and associated demographic data were 92% in Lake Munmorah and 93% in Dungog, with 84% and 90% of children respectively being measured for lung function, atopy, and bronchial reactivity. There were 419 boys and 432 girls aged 5 to 12 years. MEASUREMENTS AND MAIN RESULTS: Main outcome measures were current wheeze and bronchial hyper-reactivity, defined as a fall in forced expiratory volume in 1 second (FEV1) or peak expiratory flow (PEF) of 20% or more. Current wheeze was reported in 24.8% of the Lake Munmorah children compared with 14.6% of the Dungog children. Bronchial hyper-reactivity was similar for both groups--25.2% in Lake Munmorah and 22.3% in Dungog. The mean baseline FEV1 was lower in Lake Munmorah than in Dungog (p < 0.001). Dungog children were more likely to have positive skin test to house dust mite (Dungog 27.0%, Lake Munmorah 20.2%, p = 0.028) but there were no other differences in skin test atopy in the two towns. After adjusting for age, gender, any smoker in the house, and positive dust mite skin test, the odds of current wheeze in Lake Munmorah compared with Dungog was 2.16 (95% confidence interval 1.45, 3.15). CONCLUSIONS: Baseline lung function was lower and reported symptoms of asthma were higher in the power station town, but bronchial hyper-reactivity and skin test defined atopy were similar in the two communities. These results are consistent with the previous study and confirm the increased presence of reported symptomatic illness in the town near power stations.

Asthma↗
PubMed1993

Short intervention can improve knowledge about childhood asthma in nursing staff.

Twenty-nine community or hospital-based general nurses from the Upper Hunter Valley attended a 3-hr seminar on asthma and completed a previously validated asthma knowledge questionnaire before and 6 weeks after the seminar. The mean initial score (maximum possible 31) was 20.6 [95% confidence interval (CI) 19.1-22.0], which increased at follow-up to 26.2 (95% CI 25.0-27.3). Only 5 of 29 nurses scored 24 or more initially compared with 17 of 21 at follow-up. Even after the seminar, the nurses had major deficiencies in knowledge about preventive medication and the management of exercise-induced asthma.

Asthma↗
PubMed1991

The complete amino acid sequence of feline beta-lactoglobulin II and a partial revision of the equine beta-lactoglobulin II sequence.

The amino acid sequence of feline beta-lactoglobulin (designated II) has been determined. The protein chain is 163 amino acids long with a relative molecular mass of 18,558. The primary structure was determined by sequencing of native protein (residues 1-25), BPNS-skatole cleavage fragments and the peptides obtained by proteolytic cleavage with V8 proteinase and TPCK-trypsin. Feline beta-lactoglobulin II has 53 and 57% positional identities with bovine beta-lactoglobulin A and equine beta-lactoglobulin I, respectively, and approx. 68% with a revised sequence of equine beta-lactoglobulin II. The equine beta-lactoglobulin II sequence was re-examined between positions 78 and 122 resulting in a major revision in this area with only a single insertion to give a total of 163 residues.

Amino Acid Sequence↗
PubMed1991

Spontaneous and 9-aminoacridine-induced frameshift mutagenesis: second-site frameshift mutation within the N-terminal region of the lacI gene of Escherichia coli.

A novel forward mutational system, based on the acquisition of an Iq-d dominant phenotype from an initial Iq- recessive state, was used to identify second-site frameshift mutation [+/- 1(+/- 3n) events] within the N-terminal region of the lacI gene of Escherichia coli. The DNA sequences are described of forty-six spontaneous and twenty 9-aminoacridine(9-AA)-induced second site mutations. Although -1 frameshift events dominate both spectra, the nature and site specificity of these events clearly distinguish two mutational distributions. The spontaneous distribution contains two -(A:T) frameshift hotspots; one within a monotonic A5 run (9 occurrences), the other at a 5'-CACAACAAC-3' sequence (12 occurrences). In contrast 17 of the 20 mutations recovered after 9-AA treatment involve the loss of a G:C pair, 14 of which occur at a single site (5'-CGGGC-3'). The striking specificity of the observed mutational hotspots is of interest since this open genetic target contains similar sequences which were infrequently recovered.

Aminacrine↗
PubMed1991

Specificity of recA441-mediated (tif-1) mutational events.

To investigate the impact of SOS induction on the distribution of spontaneous mutation, 111 recA441-mediated mutations were characterized at the DNA sequence level in the lacI gene of Escherichia coli. A 2.6-fold enhancement in lacI- mutation frequency was observed after induction of the SOS system in the absence of mutagenic treatment, and specific classes of mutational events were induced. G:C----C:G, G:C----T:A and A:T----T:A transversion events were specifically enhanced after SOS induction. A preferential 5'-Y-Purine-3' neighbouring base specificity for these transversion events is reported here (normalised for mutation of the purine residue). In addition, a preference for transversion events at 5'-C/GTGG-3' sequences is also observed. Fifty events were recovered at the lacI "frameshift hotspot site" and were equally represented by 4 bp addition and deletion events. This 1:1 ratio deviates significantly from the 4:1 distribution characteristic of spontaneous frameshift mutation in the RecA+ background and is a consequence of the fourfold induction of the (-)4 event. This abberrant distribution was confirmed by oligomeric probing of 474 independent recA441-mediated spontaneous lacI- mutations.

Amino Acids↗
PubMed1991

A simple score and questionnaire to measure group changes in dietary fat intake.

BACKGROUND: A short 12-term questionnaire was designed to measure changes in the dietary intake of saturated and total fat among groups of people attending health promotion events. A simple score (the fat-habits score) derived from the questionnaire was compared with estimates of saturated and total fat intake (% total energy) estimated from a standard 180-item food frequency questionnaire of 105 children (less than 18 years) and 202 adults (greater than 18 years). RESULTS: The correlation coefficients for saturated fat intake and the fat-habits score were 0.60 (95% CI = 0.50 to 0.68) in adults and 0.54 (95% CI = 0.39 to 0.66) in children, and those for total fat and the fat-habits score were 0.46 (95% CI = 0.41 to 0.56) in adults and 0.40 (95% CI = 0.22 to 0.55) in children. Linear regression equations relating the fat-habits score to saturated and total fat were used to predict changes in fat intake in 12 children and 27 adults who completed both questionnaires 6 months apart. The differences between the predicted changes in saturated and total fat and the observed changes measured by the food frequency questionnaires were not significant (saturated fat: adults -0.3%, 95% CI = -1.3 to 0.7%; children -0.2%, 95% CI = -1.7 to 1.3%; total fat: adults -0.6%, 95% CI = -2.9 to 1.7%; children -0.4%, 95% CI = -2.8 to 2.0%). The study had a 90% power of detecting a difference between the predicted and the observed changes for saturated fat of greater than +/- 1.7% (adults) and +/- 2.5% (children), and for total fat of greater than +/- 3.9% (adults) and +/- 4.0% (children). Conclusion. Thus simple scores can be used to evaluate group changes in fat intake.

Adolescent↗
PubMed1990

Colony hybridisation in Escherichia coli: a rapid procedure for determining the distribution of specific classes of mutations among a number of preselected sites.

Colony probe oligonucleotide hybridisation was used for the unambiguous identification of DNA alterations and the determination of distributions and frequencies of forward mutation at the molecular level. To demonstrate the reliability and versatility of this technique, distributions of spontaneous and ethyl methanesulfonate (EMS)-induced mutations have been reproduced using a battery of oligonucleotide probes complementary to specific sites and classes of mutation. These studies are indicative of the diagnostic potential of oligonucleotide colony hybridisation to the characterisation of mutation; oligonucleotide hybridisation used in conjunction with a well studied mutational target provides a rapid and reliable alternative to DNA sequencing for the characterisation of all classes of mutations.

Alkylating Agents↗
PubMed1990

Feline whey proteins: identification, isolation and initial characterization of alpha-lactalbumin, beta-lactoglobulin and lysozyme.

1. Both alpha-lactalbumin and beta-lactoglobulin-like proteins were detected in the whey fraction of feline milk by immunoblotting with rabbit antisera to alpha-lactalbumin and beta-lactoglobulin, respectively. 2. alpha-Lactalbumin was found to occur in both glycosylated and unglycosylated forms in approximately equal concentrations. No polymorphism of feline alpha-lactalbumin was found. 3. Feline beta-lactoglobulin-like proteins produced complex electrophoretic patterns that appear to be determined by three distinct loci. Between two and five genetic variants are expressed by each locus. 4. Lysozyme was detected at levels of approximately 1 mg/ml in skim milk. 5. The identifications of the proteins as alpha-lactalbumin, beta-lactoglobulin and lysozyme were confirmed by determination of N-terminal amino acid sequences.

Amino Acid Sequence↗
PubMed1988

Missense mutation in the lacI gene of Escherichia coli. Inferences on the structure of the repressor protein.

The lac repressor has been studied extensively but a precise three-dimensional structure remains unknown. Studies using mutational data can complement other information and provide insight into protein structure. We have been using the lacI gene-repressor protein system to study the mutational specificity of spontaneous and induced mutation. The sequencing of over 6000 lacI- mutations has revealed 193 missense mutations generating 189 amino acid replacements at 102 different sites within the lac repressor. Replacement sites are not distributed evenly throughout the protein, but are clustered in defined regions. Almost 40% of all sites and over one-half of all substitutions found occur within the amino-terminal 59 amino acid residues, which constitute the DNA-binding domain. The core domain (residues 60 to 360) is less sensitive to amino acid replacement. Here, substitution is found in regions involved in subunit aggregation and at sites surrounding residues that are implicated in sugar-binding. The distribution and nature of missense mutational sites directs attention to particular amino acid residues and residue stretches.

Amino Acid Sequence↗
PubMedDate not supplied

Mechanisms of spontaneous mutation in DNA repair-proficient Escherichia coli.

This paper describes the DNA sequence analysis of 729 independent spontaneous lacI- mutations. This total is comprised of 478 novel mutations and 251 previously described events, and therefore should allow a more comprehensive view of spontaneous mutation in Escherichia coli. The spectrum is dominated by a hotspot (71% of all events). Mutations at this site consist of related addition and deletion events involving a number of repetitive sequences. Here we discuss how the frequency and proportion of these events vary in different DNA repair-deficient genetic backgrounds. The distribution of non-hotspot events includes base substitutions (38%), deletions (35%), frameshifts (14%), duplications (4%) and insertion elements (4%). G:C----A:T events dominate among base substitutions, while G:C----C:G events are the least common; the remaining types of base substitution are equally represented. Among deletions, a significant number do not display repeated sequences at their endpoints (26/72). However, almost all multiply recovered events (15/17) possess repeated sequences capable of accounting for the deletion endpoints. Similarly, over half of all duplications recovered (5/7) display repeated endpoints. Single-base frameshifts are equally divided between A:T and G:C sites, in each case (-) 1 events occur 3-fold more frequently that (+) 1 events. A comparative analysis of each mutational class recovered to lacI- spectra available in a variety of DNA repair/metabolism-deficient strains is presented here in an attempt to assess possible contributions from chemical, physical and enzymic sources of damage.

Base Sequence↗
PubMedDate not supplied

Climbing frame.

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Career Mobility↗