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Biomedical subjects

L Crossland

Publications and source records attributed to L Crossland.

18 recordsLinked to original sources
PubMed1999

Consumers' after hours health care decisions. Comparison between those who did and those who did not seek care in an Australian provincial city.

OBJECTIVE: To compare the demographic and illness characteristics of people who sought after hours care with those who did not, to identify differences that might be exploited in patient education regarding 'appropriate' use of after hours care. METHOD: Structured telephone interview survey of randomly selected householders in Townsville. RESULTS: An 88% response rate was achieved (1227/1402). A total of 10.8% (133/1227) of respondents had sought after hours care for themselves in the 3 months before interview. A further 10.9% (134/1227) had decided against seeking care during that period. The two groups were demographically similar, except in terms of health care training and perceived travel time to after hours care. Self reported conditions varied only for ICPC general, musculoskeletal and skin chapters. Symptom related issues were most important in the decision to seek care, while self care procedures were the most common reason for not seeking care, followed by access related issues. CONCLUSIONS: The decision to seek care is an individual process that cannot be reliably predicted by demographic characteristics. Broad scale community education programs aimed at reducing 'inappropriate' use of after hours services would need to find a balance between increasing knowledge for self care of minor conditions and emphasising the importance of being alert to signs and symptoms of life threatening conditions.

Adolescent↗
PubMed1998

Activation of latent transgenes in Arabidopsis using a hybrid transcription factor.

A hybrid transcription factor comprising a fusion of the DNA-binding domain of Saccharomyces cerevisiae GAL4 and the transcription activation domain of maize C1 was expressed in stably transformed Arabidopsis. Additional transgenic lines were created containing test genes controlled by a synthetic promoter consisting of concatemeric copies of the cis-acting site recognized by GAL4 (UASG) fused to a minimal promoter. The GAL4/C1 effector line was crossed to two lines containing a synthetic promoter/GUS fusion. Both histochemical staining and GUS activity assays indicate strong activation of GUS expression was achieved only after crossing. The GAL4/C1 effector line was also crossed to 15 lines containing a synthetic promoter/antisense adenylosuccinate synthetase gene. Severely retarded growth, and in some cases lethality, was observed in 40% of the F1 lines. This system of activation by crossing is generally useful for activating expression of test transgenes.

Arabidopsis↗
PubMed1998

Methodological issues in medical workforce analysis: implications for regional Australia.

Medical workforce data have a profound impact on health policy formulation, but derived doctor population ratios (DPR) are often more relevant to plotting national trends than providing a detailed regional or local workforce perspective. Regional workforce data may be more useful if national approaches are augmented by local information. In developing a detailed workforce analysis for one region of Australia, the authors encountered several challenging methodological issues, including the accuracy of medical workforce databases, clarity of definition of community boundaries, interpretation of workforce definitions and the difficulty accounting for local community needs. This paper discusses the implications for regional workforce research.

Health Services Research↗
PubMed1998

Case-control study of salmeterol and near-fatal attacks of asthma.

BACKGROUND: A case-control study was undertaken to investigate the hypothesis that the use of the long acting beta agonist salmeterol increases the risk of a near-fatal attack of asthma. METHODS: The cases comprised admissions to the intensive care unit (ICU) for asthma in 14 major hospitals within the Wessex region in 1992. For each of the cases four age-matched controls were selected from asthma admissions to the same hospital during the same period. Information on prescribed drug therapy for the 48 cases and 185 controls was collected from the hospital admission records. RESULTS: The patients admitted to the ICU had greater chronic asthma severity and had generally been prescribed more asthma drugs than the control admissions to hospital. The relative risk of a near-fatal attack of asthma in patients prescribed inhaled salmeterol was 2.32 (95% CI 1.05 to 5.16), p = 0.04. However, the salmeterol relative risk decreased to 1.42 (95% CI 0.49 to 4.10), p = 0.52 when the analysis was restricted to the more chronically severe patients (those in the subgroup of patients with a hospital admission for asthma in the previous 12 months). These findings suggest that the increased unadjusted relative risk with salmeterol is predominantly due to confounding by severity--that is, the increased relative risk is due to patients with more severe asthma (at greatest risk of a near-fatal asthma attack) being preferentially prescribed salmeterol. This interpretation is supported by the finding in this study that, within the control group (selected from the population of asthmatics requiring hospital admission), salmeterol was preferentially prescribed to the most severe patients (a threefold greater prescription of salmeterol to control patients if they had been admitted to hospital in the 12 months prior to the index admission). There was no increased risk of a near-fatal attack of asthma in patients prescribed a beta agonist by metered dose inhaler (OR 0.75 (95% CI 0.31 to 1.78), p = 0.51). In contrast, the relative risks for beta agonists delivered by nebulisation (OR 3.86 (95% CI 1.99 to 7.50), p < 0.001) and oral theophylline (OR 2.45 (95% CI 1.26 to 4.78), p < 0.01) were increased and did not markedly decrease when the analysis was restricted to the more severe asthmatic subjects. CONCLUSIONS: Although these findings are not conclusive, particularly because of the small numbers involved in some subgroup analyses, they suggest that the use of salmeterol by patients with chronic severe asthma is not associated with a significantly increased risk of a near-fatal attack of asthma. If a near-fatal asthma attack is considered to be an intermediate step in a process by which a severe attack of asthma may become fatal, these results would suggest that salmeterol is unlikely to be associated with an increased risk of death, at least by this mechanism.

Adolescent↗
PubMed1998

Resource allocation in general practice care.

OBJECTIVE: Complexity of care provided by general practitioners (GPs) is poorly addressed by current measures. Resource allocation for health care in inpatient settings utilises complex descriptions of clinical content and process to produce 'casemix' resource units. This pilot project explored the potential application of these concepts to the funding of general practice in Australia. METHOD: Prospective data were collected from three practices in the same community on one day in the same week. GP generated data included reasons for encounter, age and gender of the patient, whether the problems were new or old, what tests and referrals were initiated for each problem and global complexity ratings. Data collected from the patients included problems presented, problems not dealt with and satisfaction ratings. These data were used to explore the determinants of consultation complexity in general practice. RESULTS: There were statistically significant correlations between: global complexity and problem type (coded to ICPC Chapter); global complexity and number of problems seen; and global complexity and consultation billing level. A resource allocation formula which considers broader descriptions than current fee descriptors is suggested. CONCLUSIONS: Aspects of the casemix concept may have some relevance to how resources could be allocated in general practice, but this would require substantial further investigation.

Australia↗
PubMed1997

Why doctors leave rural practice.

Retention of rural doctors remains difficult because of complex factors that influence decisions of medical families. This study explores the reasons why Queensland rural doctors left their communities during 1995. Semi-structured interviews were conducted with contactable former rural doctors who claimed that they had entered rural practice with the intention to stay for a substantial period of time. The interviews were audiotaped, transcribed and analysed using NUD.IST software. Participants appeared to be subject to a dynamic balance between opposing pressures to stay and pressures to leave. In time, they became susceptible to 'triggers' to leave. These triggers were sometimes locality-specific and could be difficult to address, particularly without early intervention. We believe that it should be possible to develop strategies that address specific concerns of rural doctors, particularly if they are identified early. The optimum period of stay in rural practice should be reconsidered, such that moderate stays should be rewarded in a way that retains the doctors in some form of rural, or near-rural practice.

Family Practice↗
PubMed1996

Identification of tissue-specific, dehydration-responsive elements in the Trg-31 promoter.

Trg-31 is a pea gene which is rapidly induced in response to dehydration stress. Trg-31 belongs to a family of membrane intrinsic proteins that play a role in facilitating inter-membrane transport. In order to understand the mechanism of regulation of Trg-31 expression we defined the cis-acting elements of the Trg-31 promoter and the trans-acting factors that interact with them. Deletion analysis of the Trg-31 promoter in transgenic tobacco plants indicated the presence of two positive regulatory region: (1) between the -1412 to -1066 nucleotides and (2) between the -559 to -391 nucleotides, with respect to the transcription initiation site. A negative regulatory element was also identified between -1066 and -559 nucleotides. All three regulatory regions specifically regulated Trg-31 induction in leaf tissue and had little or no effect on Trg-31 induction in root tissue. Gel-mobility shift assays indicated the presence of leaf nuclear proteins that interacted with the -1412 to -1066 and -1066 to -559 regions and an 'ABRE-like' sequence at -74 in the 5' promoter region of Trg-31.

Aquaporins↗
PubMed1994

The self reported prevalence of asthma symptoms amongst adult New Zealanders.

AIMS: To examine the prevalence of asthma symptoms in a random population sample of New Zealand adults aged 20-44 years drawn from the general and Maori electoral rolls as phase I of an international study of asthma prevalence. METHODS: Subjects aged 20-44 years in Auckland, Hawkes Bay, Wellington and Christchurch, were selected randomly from the electoral rolls and sent a one page screening questionnaire, asking about respiratory symptoms, asthma attacks and asthma treatment. They were also asked to record their ethnic affiliation. Nonresponders were subsequently sent two written reminders followed by a telephone questionnaire where possible. RESULTS: A response rate of 84% was achieved. The study found a high prevalence of asthma symptoms, with 26% reporting wheezing in the last year, 8% experiencing an attack of asthma in the last year and 9% currently using asthma medication. Females were more likely to have had wheezing in the last year (26.6%) and be on treatment for asthma (9.8%) compared with males (24.7% and 7.5% respectively). Small regional differences were found with more reported symptoms and asthma treatment in Wellington and Christchurch, compared with Auckland and Hawkes Bay. Maori were more frequently symptomatic (35.2%) than nonPolynesian (24.8%) but were no more likely to report an attack of asthma (Maori 9.0%, nonPolynesian 7.7%) or be currently receiving asthma treatment (Maori 10.0%, nonPolynesian 8.6%). Asthma symptoms tended to decline with age in non Maori but increased with age in Maori. Adjustment of prevalence rates by two independent methods suggests that nonresponse bias has not significantly inflated these rates. CONCLUSIONS: The symptoms of asthma and their treatment are common in young New Zealanders, affecting one in three Maori and one in four nonMaori. One in ten of this adult population currently receive asthma treatment.

Adult↗
PubMed1994

Plant activating sequences: positively charged peptides are functional as transcriptional activation domains.

Plant sequences that act as transcriptional activation domains in yeast as well as in plants have been isolated by genetic selection in yeast. The selection was based on the reconstitution of a functional GAL4 transcriptional activator. Since the peptides show no homology with reported activation domains, they represent a new class of activating sequences. The sequence P1, which is 10 amino acids long, is the shortest functional activation domain reported. A cDNA that encodes the P14 class (peptides P14-P18) activating sequence have been cloned. The protein exhibits strong homology (higher than 50% amino acid identity) with the BBC1-related sequences, a highly conserved family of basic proteins containing nuclear localization signals. The P14 and P15 peptides are the most effective plant activating sequences. The P14 and P15 peptides are highly hydrophilic, positively charged and mostly unstructured. These properties are at odds with the ones usually found in known activation domains.

Amino Acid Sequence↗
PubMed1994

Cloning and characterization of a maize pollen-specific calcium-dependent calmodulin-independent protein kinase.

A calcium-dependent calmodulin-independent protein kinase (CDPK) has been cloned from maize (Zea mays). The sequence predicts a 550-amino acid (predicted molecular mass is 60 kDa) protein with two major functional domains: an N-terminal catalytic domain highly homologous to protein kinases and a C-terminal domain resembling calmodulins. Northern analysis shows that the expression of the maize CDPK gene is pollen specific and that its transcription is restricted to late stages of pollen development. Western blots reveal a major abundance of CDPK protein at the stage of pollen germination. In vitro germination and pollen tube growth are impaired upon addition of a calmodulin antagonist (calmidazolium), CDPK inhibitors (W-7), and antisense oligonucleotides directed against CDPK mRNA. These observations indicate that the function of the pollen-specific maize CDPK protein is required for germination and pollen tube growth.

Amino Acid Sequence↗
PubMed1994

Community-based asthma care: trial of a "credit card" asthma self-management plan.

Although asthma self-management plans are widely recommended as essential in the long-term treatment of adult asthma, there have been few studies examining their use. Our objective was to assess the effect of a "credit card" adult asthma self-management plan in a community experiencing major health problems from asthma, by means of a before and after intervention trial of the efficacy of the "credit card" plan, when introduced through community-based asthma clinics. The participants were 69 Maori people with asthma. The "credit card" plan consisted of written guidelines for the self-management of asthma, based on self-assessment of asthma severity, printed on a plastic card. On one side, management guidelines were based on the interpretation of peak expiratory flow rate (PEFR) recordings, whilst the reverse side was based on symptoms. The outcome measures used were before and after comparison of markers of asthma morbidity and requirement for acute medical treatment; and a structured questionnaire assessing the acceptability and use of the credit card plan. Following the introduction of the plan, the mean PEFR increased from 347 to 389 l.min-1, the percentage of nights woken fell from 30.4 to 16.9%, and the number of days "out of action" fell from 3.8 to 1.7%. The requirements for acute medical treatment also fell during the intervention period. Most participants commented favourably on the content and usefulness of the plan. In the situation of worsening asthma, 28% of subjects found the peak flow side of the card most helpful, 7% the symptoms side, and 48% found both sides equally helpful.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Prevalence of asthma symptoms among adolescents in the Wellington region, by area and ethnicity.

AIMS: To compare the self-reported prevalence of asthma symptoms, among 12 to 15 year olds in three districts in the greater Wellington region, and to compare prevalence among three ethnic groups--Maori, Pacific Island and others. METHODS: Third form students from 13 secondary schools in the Wellington region, were surveyed using a video questionnaire and a standardised written questionnaire, during July 1991. RESULTS: Using the video questionnaire, the prevalence of wheeze during the previous 12 months was similar in Wellington city (32%), Lower Hutt (38%), and Porirua (37%); the corresponding findings using the written questionnaire were 28%, 27% and 30% respectively. The reported prevalence was also similar among Maori (38% using the video and 29% using the written questionnaire) and other children (36% and 30% respectively), but lower among Pacific Island children (31% and 20% respectively). The prevalence and frequency of severe attack of wheezing was similar in all three districts and all three ethnic groups. CONCLUSIONS: These findings contradict previous speculations of possible differences in asthma prevalence or severity within the greater Wellington region. They are consistent with other evidence that there are at most minor differences in asthma prevalence between Maori and nonMaori children in New Zealand; however, asthma prevalence may be lower among Pacific Island children. Thus ethnic differences in asthma morbidity and mortality are not likely to be due to differences in prevalence, but more likely relate to differences in access to and delivery of asthma care.

Adolescent↗
PubMed1993

Tissue-specific expression of a plant turgor-responsive gene with amino acid sequence homology to transport-facilitating proteins.

We report the isolation of a turgor-responsive gene of pea, trg-31, whose transcription induced within 30 min after the loss of leaf turgor. Structure of the coding region and 1.4 kb of 5' untranslated region was determined by DNA sequencing. A 3 kb promoter fragment from trg-31 was fused to a beta-glucuronidase (GUS) reporter gene in pBI101, tobacco leaf disks and mature plants analyzed for turgor-responsive induction of GUS mRNA. Significant amino acid sequence homology exists between trg-31 and putative transport proteins of bovine, Phaseolus, soybean and Escherichia coli membranes.

Amino Acid Sequence↗
PubMed1990

Promoter sequences from a maize pollen-specific gene direct tissue-specific transcription in tobacco.

A set of 5' promoter deletions from Zmg13, a genomic clone of a pollen-specific gene of maize, has been transcriptionally fused to a beta-glucuronidase (GUS) reporter gene in the binary vector pBI101. Tobacco leaf disks were transformed and mature plants analyzed for GUS activity directed by the Zmg13 promoter constructs. Transgenic plants containing the 375 bp Zmg13 sequence from -314 to +61 relative to the transcription start site transcribed GUS RNA and expressed active GUS enzyme in mature pollen but not in leaves. Plants transformed with a 35S CaMV promoter-GUS transcriptional fusion expressed GUS RNA in leaves but not in pollen. Neither GUS RNA or active enzyme could be detected in pollen or leaves from plants containing a 124 bp Zmg13-GUS transcriptional fusion missing the putative Zmg13 TATA box. No GUS RNA or enzyme expression was not detected in non-transformed tobacco. RNA and GUS histochemical analysis of the T1 generation confirmed that the temporal expression pattern of Zmg13-GUS transcription in tobacco followed that of the native gene in maize and that the Zmg13 promoter sequences from the maize gene are able correctly to direct genetically stable, tissue-specific gene expression in transgenic tobacco plants.

Base Sequence↗
PubMed1989

Fusion protein-based epitope mapping of phytochrome. Precise identification of an evolutionarily conserved domain.

Fusion proteins are used to define with precision an evolutionarily conserved domain on the carboxyl-terminal portion of the chromoprotein phytochrome. Simultaneously, assignments of two other epitopes are made with significantly greater precision, while the location of a fourth is confirmed. The epitope-mapping method that is described here is systematic, using complementary, overlapping nested sets of fusion proteins of predefined sequence rather than randomly generated peptides. Moreover, in contrast to previous methods, this approach yields rigorous and unambiguous assignments because it relies solely upon the ability of an antibody to detect a given polypeptide. A cDNA fragment encoding phytochrome amino acids 464-1129, which is its carboxyl terminus, was identified in lambda gt11 and subcloned in frame into the lacZ alpha sequence of pUC18. Four nested sets of subclones in pUC18 were created by digestion with selected restriction endonucleases and with the exonuclease Bal31. Fusion proteins were analyzed by immunoblotting following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The epitope for monoclonal antibody Oat-13 was confirmed to be between residues 551 and 617, while the epitopes for Oat-8 and Oat-28 were narrowed to 624-686 and 624-747, respectively. The epitope recognized by Pea-25, Pea-2, and Oat-15 was resolved unequivocally to a sequence of only seven residues (residues 765-771): N-Pro-Ile-Phe-Gly-Ala-Asp-Glu-C.

Amino Acid Sequence↗
PubMed1980

Polarity of Tn5 insertion mutations in Escherichia coli.

We assessed the effect of insertions of the kanamycin resistance transposon Tn5 in the lac operon of Escherichia coli on the expression of distal genes lacY and lacA (melibiose fermentation at 41 degrees C and thiogalactoside transacetylase synthesis, respectively). Every insertion mutation tested (41 in lacZ and 23 in lacY) was strongly polar. However, approximately one-third of the insertion mutants expressed distal genes at low levels due to a promoter associated with Tn5. To localize this promoter, we (i) reversed the orientation of Tn5 at several sites and (ii) replaced wild-type Tn5 with several substitution derivatives which lack Tn5's central region. Neither alteration changed the expression of distal genes. Thus, in contrast to transposons IS2 and TnA. Tn5's ability to turn on distal gene expression is not due to a promoter in its central region and therefore is not dependent on the overall orientation of Tn5 in the operon. Our results suggest that the promoter is within 186 base pairs of the ends of Tn5. It is possible that the promoter is detected in only a fraction of insertions because it overlaps Tn5-target sequence boundary.

Acetyltransferases↗