Search PubMed⌕ Search

Biomedical subjects

Alison Smith

Publications and source records attributed to Alison Smith.

At least 19 recordsLinked to original sources
PubMed2006

2,3,7-Trisubstituted pyrazolo[1,5-d][1,2,4]triazines: functionally selective GABAA alpha3-subtype agonists.

Novel synthetic routes have been devised for the preparation of previously inaccessible 2,3,7-trisubstituted pyrazolo[1,5-d][1,2,4]triazines 2. These compounds are high affinity ligands for the GABA(A) benzodiazepine binding site and some analogues show functional selectivity for agonism at alpha3-containing receptors over alpha1-containing receptors with the lead compound being 32.

Binding Sites↗
PubMed2006

Identification of acid reflux cough using serial assays of exhaled breath condensate pH.

BACKGROUND: Chronic cough is a common problem, frequently caused or exacerbated by acid reflux. Diagnosis of acid reflux cough is haphazard currently, often relying on long therapeutic trials of expensive medications. We tested the hypothesis that the most relevant mechanistic component of acid reflux in chronic cough is when it rises to the level of the airway where acid can potentially be aspirated. We further wished to determine if multi-sample exhaled breath condensate (EBC) pH profiles can identify chronic cough patients likely to respond to proton pump inhibitor therapy. METHODS: 59 subjects were recruited for this study. Initially we examined EBC pH (gas-standardized with Argon) in the setting of 15 experimental pharyngeal acid challenges to determine duration of EBC acidification. Subsequently, we enrolled 22 healthy subjects to determine a normal multi-sample exhaled breath condensate pH profile over 1-3 days. We additionally obtained multi-sample EBC pH profiles in 22 patients with chronic cough. These samples were timed to occur after coughing episodes. Exhaled breath condensate pH was measured after gas standardization. RESULTS: We found that exhaled breath condensate pH is substantially reduced for approximately 15 minutes after pharyngeal acid load. Healthy subjects rarely have any low EBC pH values (defined as < 7.4 based on a normative reference range from 404 healthy subjects). Patients with chronic cough who subsequently responded well to proton pump inhibition (n = 8) invariably had one or more cough episodes associated with EBC acidification. No patient who had normal EBC pH with each of their cough episodes reported a clinically relevant response to proton-pump inhibition. CONCLUSION: Patients whose cough responds to proton pump inhibition have transient exhaled breath condensate acidification with coughing episodes, supporting the role of airway acidification in reflux-triggered cough. Multi-sample EBC pH profiles, involving samples collected immediately subsequent to a coughing episode, may be useful appropriately to direct therapy to those patients with cough who have relevant acid reflux.

Journal Article↗
PubMed2006

Endogenous S-nitrosoglutathione modifies 5-lipoxygenase expression in airway epithelial cells.

S-Nitrosoglutathione (GSNO) is an endogenous bronchodilator with several beneficial pulmonary effects. Levels are decreased in the asthmatic airway, and GSNO inhalation has been proposed as an asthma therapy. 5-lipoxygenase (5-LO) is the rate-limiting enzyme in the synthetic pathway for cysteinyl leukotrienes (CysLTs), bronchoconstricting agents that are overproduced in asthma. Here, we have studied the effect of GSNO on the expression of 5-LO in human airway A549 cell lines and in primary normal human tracheobronchial epithelial (NHBE) cells in vitro. GSNO at concentrations of 0.5-1 microM caused a 3- to 6-fold increase in 5-LO expression. However, GSNO at>5 microM significantly inhibited both 5-LO expression and LT production. We also found that airway epithelial cells had gamma-glutamyl transpeptidase (gamma-GT) activity. The effect of 1 microM GSNO on 5-LO expression was prevented by the gamma-GT inhibitor, acivicin, suggesting a convergence of GSNO and CysLT metabolic pathway that may be relevant to asthma. Our data demonstrate that GSNO levels 5microM suppresses 5-LO expression. These data suggest that GSNO might inhibit 5-LO expression in the clinical setting.

Arachidonate 5-Lipoxygenase↗
PubMed2006

A transglucosidase necessary for starch degradation and maltose metabolism in leaves at night acts on cytosolic heteroglycans (SHG).

The recently characterized cytosolic transglucosidase DPE2 (EC 2.4.1.25) is essential for the cytosolic metabolism of maltose, an intermediate on the pathway by which starch is converted to sucrose at night. In in vitro assays, the enzyme utilizes glycogen as a glucosyl acceptor but the in vivo acceptor molecules remained unknown. In this communication we present evidence that DPE2 acts on the recently identified cytosolic water-soluble heteroglycans (SHG) as does the cytosolic phosphorylase (EC 2.4.1.1) isoform. By using in vitro two-step (14)C labeling assays we demonstrate that the two transferases can utilize the same acceptor sites of the SHG. Cytosolic heteroglycans from a DPE2-deficient Arabidopsis mutant were characterized. Compared with the wild type the glucose content of the heteroglycans was increased. Most of the additional glucosyl residues were found in the outer chains of SHG that are released by an endo-alpha-arabinanase (EC 3.2.1.99). Additional starch-related mutants were characterized for further analysis of the increased glucosyl content. Based on these data, the cytosolic metabolism of starch-derived carbohydrates is discussed.

Arabidopsis↗
PubMed2006

Normative data for pH of exhaled breath condensate.

INTRODUCTION: Measurement of pH is one of the simplest and most technically validated biomarkers studied in exhaled breath condensate (EBC). The pH of EBC has been found to be lower than controls in many respiratory disorders. Published data from normal control subjects have been reasonably consistent, but the data sets are not large. This study was undertaken to establish normative EBC pH reference values. PARTICIPANTS: Four hundred four healthy subjects of all ages were enrolled. INTERVENTIONS: Each participant provided a single EBC sample using a disposable collector at modest temperature so that EBC was collected as a liquid. MEASUREMENTS AND RESULTS: Samples of EBC were bubbled with argon gas to standardize for carbon dioxide, and pH was recorded with a calibrated and validated glass microelectrode on stabilization. The median EBC pH was 8.0 with interquartile (25 to 75%) range of 7.8 to 8.1. There were no differences based on age, sex, or race. The distribution is skewed, with 6.4% of EBC samples having a pH range < 7.4. CONCLUSIONS: An extensive normal data set now exists that reveals EBC pH is maintained in a modestly alkaline and tight range in subjects who consider themselves healthy.

Adolescent↗
PubMed2006

Added value.

Explore the source record for details and available documents.

Accreditation↗
PubMed2005

Pyrazolopyridinones as functionally selective GABAA ligands.

2,5-Dihydro-3H-pyrazolo[4,3-c]pyridin-3-ones are GABAA receptor benzodiazepine binding site ligands, which can exhibit functional selectivity for the alpha3 subtype over the alpha1 subtype. SAR studies to optimize this functional selectivity are described.

Azo Compounds↗
PubMed2005

Functional genomic analysis of the AUXIN/INDOLE-3-ACETIC ACID gene family members in Arabidopsis thaliana.

Auxin regulates various aspects of plant growth and development. The AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) genes encode short-lived transcriptional repressors that are targeted by the TRANSPORT INHIBITOR RESPONSE1/AUXIN RECEPTOR F-BOX proteins. The Aux/IAA proteins regulate auxin-mediated gene expression by interacting with members of the AUXIN RESPONSE FACTOR protein family. Aux/IAA function is poorly understood; herein, we report the identification and characterization of insertion mutants in 12 of the 29 Aux/IAA family members. The mutants show no visible developmental defects compared with the wild type. Double or triple mutants of closely related Aux/IAA genes, such as iaa8-1 iaa9-1 or iaa5-1 iaa6-1 iaa19-1, also exhibit wild-type phenotypes. Global gene expression analysis reveals that the molecular phenotypes of auxin-treated and untreated light-grown seedlings are unaffected in the iaa17-6 and iaa5-1 iaa6-1 iaa19-1 mutants. By contrast, similar analysis with the gain-of-function axr3-1/iaa17-1 mutant seedlings reveals dramatic changes in basal and auxin-induced gene expression compared with the wild type. Expression of several type-A ARABIDOPSIS RESPONSE REGULATOR genes and a number of genes involved in cell wall biosynthesis and degradation is repressed in axr3-1/iaa17-1. The data suggest extensive functional redundancy among Aux/IAA gene family members and that enhanced stability of the AXR3/IAA17 protein severely alters the molecular phenotype, resulting in developmental defects.

Amino Acid Sequence↗
PubMed2005

Assaying all of the nitrogen oxides in breath modifies the interpretation of exhaled nitric oxide.

Exhaled nitric oxide (NO) assays measure the quantity of NO that emanates from the airway, not the amount of NO that is formed. Consumptive processes-including oxidation reactions-decrease the amount of gas phase NO available for exhalation. Higher oxides of nitrogen (HiNO(x)) are resulting reaction products, and are easily measured in exhaled breath condensate (EBC). We performed concurrent sampling of exhaled breath for gas phase NO and EBC HiNO(x) in controls and stable asthmatics. We identified that, mole for mole, asthma patients hourly exhale more HiNO(x) than they do NO, with a HiNO(x)/NO ratio of 1.21 (0.54-3.4). This is the reverse of the ratio found in controls, in whom the HiNO(x)/NO ratio was 0.75 (0.44-0.93), p=0.04. The sum of the hourly molar exhalation of NO and HiNO(x) was significantly higher in asthmatics (333 nmol/h (221-543) than controls (179 (138-231), p<0.001). We conclude that exhaled oxides of nitrogen are more informative when measured together as opposed to in isolation. We suggest that inflammation can be better evaluated with HiNO(x) and NO measured concurrently, and that the level of oxidation in the lung can be evaluated by comparing the easily measured ratios of HiNO(x) to NO in the exhaled breath.

Adolescent↗
PubMed2005

Candida yeast long chain fatty alcohol oxidase is a c-type haemoprotein and plays an important role in long chain fatty acid metabolism.

The industrial yeasts Candida tropicalis or Candida cloacae are able to grow on a variety of long chain alkanes and fatty acids as the sole carbon source. The complete oxidation of these substrates involves two sequential oxidative pathways: omega-oxidation, comprising the P450 alkane oxidase, a flavin-dependent membrane-bound long chain fatty alcohol oxidase [FAO] and a possible separate aldehyde oxidase [F.M. Dickinson, C. Wadforth, Purification and some properties of alcohol oxidase from alkane-grown Candida tropicalis, Biochem. J. 282 (1992) 325-331], and the beta-oxidation pathway, which utilises acylCoA substrates. We recently purified the membrane-bound long chain fatty alcohol oxidase FAO1 and confirmed it is also a c-type haemoprotein. Multiple isoforms may exist for many of these long chain fatty alcohol oxidases and the in vivo requirements for individual genes with respect to specific substrates are still being elucidated. In vitro reconstitution experiments have demonstrated that in Candida maltosa, the cytochrome P450 52A3 gene product can completely oxidise alkanes to dicarboxylic acids [U. Scheller, T. Zimmer, D. Becher, F. Schauer, W. Schunck, Oxygenation Cascade in Conversion of n-Alkanes to, -Dioic Acids Catalyzed by Cytochrome P450 52A3, J. Biol. Chem. 273 (1998) 32528-32534], potentially obviating requirements for a long chain alcohol oxidase. Here, we directly determine in vivo the role of the long chain alcohol oxidase (FAOT) in C. tropicalis, grown on a variety of substrates, followed by gene deletion. The faot double knockout has no detectable faot activity and is incapable of growth on octadecane, but it grows well on oleic acid, palmitic acid and shorter chain alkanes/fatty acids. A spontaneous mutation[s] may have occurred in the faot double gene knockout of C. tropicalis resulting in its inability to grow on oleic acid and hexadecane. The mutations demonstrate that different pathways of octadecane, hexadecane, oleic acid and palmitic acid utilisation exist in C. tropicalis.

Alcohol Oxidoreductases↗
PubMed2005

Genetic and in silico comparative mapping of the polyphenol oxidase gene in bread wheat (Triticum aestivum L.).

Polyphenol oxidases (PPOs) are involved in the time-dependent darkening and discolouration of Asian noodles and other wheat end products. In this study, a doubled haploid (DH) population derived from Chara (moderately high PPO activity)/WW2449 (low PPO activity) was screened for PPO activity based on L-DOPA and L-tyrosine assays using whole seeds. Both these assays were significantly genetically correlated (r = 0.91) in measuring the PPO activity in this DH population. Quantitative trait loci (QTLs) analysis utilising a skeleton map enabled us to identify a major QTL controlling PPO activity based on L-DOPA and L-tyrosine on the long arm of chromosome 2A. The simple sequence repeat (SSR) marker GWM294b explained over 82% of the line mean phenotypic variation from samples collected in both 2000 and 2003. Four SSR markers were validated for PPO linkage in genetically diverse backgrounds and proven to correctly predict the PPO activity in more than 92% of wheat lines. Physical mapping using deletion lines of Chinese Spring has confirmed the location of the GWM294b, GWM312 and WMC170 on chromosome 2AL, between deletion breakpoints 2AL-C to 0.85. In order to identify functional gene markers, data searches for alignments between rice BAC/PAC clones assembled on chromosome 1 and 4, chromosome 7, and (1) the wheat expressed sequence tags mapped in deletion bin (2AL-C to 0.85) and (2) the coding sequence of a previously cloned wheat PPO gene were made and found significant sequence similarities with the PPO gene or common central domain of tyrosinase. Available PPO gene sequences in the National Centre for Biotechnology Information (NCBI) database have revealed that there is a significant molecular diversity at the nucleotide and amino acid level in the wheat PPO genes.

Alleles↗
PubMed2005

Functional genomic analysis of the AUXIN RESPONSE FACTOR gene family members in Arabidopsis thaliana: unique and overlapping functions of ARF7 and ARF19.

The AUXIN RESPONSE FACTOR (ARF) gene family products, together with the AUXIN/INDOLE-3-ACETIC ACID proteins, regulate auxin-mediated transcriptional activation/repression. The biological function(s) of most ARFs is poorly understood. Here, we report the identification and characterization of T-DNA insertion lines for 18 of the 23 ARF gene family members in Arabidopsis thaliana. Most of the lines fail to show an obvious growth phenotype except of the previously identified arf2/hss, arf3/ett, arf5/mp, and arf7/nph4 mutants, suggesting that there are functional redundancies among the ARF proteins. Subsequently, we generated double mutants. arf7 arf19 has a strong auxin-related phenotype not observed in the arf7 and arf19 single mutants, including severely impaired lateral root formation and abnormal gravitropism in both hypocotyl and root. Global gene expression analysis revealed that auxin-induced gene expression is severely impaired in the arf7 single and arf7 arf19 double mutants. For example, the expression of several genes, such as those encoding members of LATERAL ORGAN BOUNDARIES domain proteins and AUXIN-REGULATED GENE INVOLVED IN ORGAN SIZE, are disrupted in the double mutant. The data suggest that the ARF7 and ARF19 proteins play essential roles in auxin-mediated plant development by regulating both unique and partially overlapping sets of target genes. These observations provide molecular insight into the unique and overlapping functions of ARF gene family members in Arabidopsis.

Arabidopsis↗
PubMed2005

Does genotype mask the relationship between psychological factors and immune function?

This paper examined the interaction between genetic influences of the polymorphic human leukocyte antigens (DRB1 and DQB1) and psychological distress on the development of cellular immunity to the novel antigen, keyhole limpet hemocyanin (KLH). Participants (n = 227) were immunized with KLH and the development of cutaneous delayed-type hypersensitivity (DTH) against KLH was examined 3 weeks later. Distress was assessed using the Profile of Mood States. DNA was typed for the serologically defined DRB1 and DQB1 antigens. There was a significant correlation between distress at immunization and the development of DTH skin test responses to KLH (n = 214, r = .24, p = .003). HLA DQ2 was weakly associated with a decreased likelihood of developing a cutaneous delayed-type hypersensitivity response against KLH (odds ratio [OR] = 1.6; confidence interval [CI] 0.9-2.7). HLA DQ5 was weakly associated with an increased likelihood of responding to the antigen (OR=0.6; CI=0.3-1.0). The correlation between distress and immune function in HLA DQ2 negative individuals was .34 (n = 136, p = .00) and in HLA DQ2 positive individuals it was .06 (n = 74, p =. 64). For HLA DQ5 negative individuals the correlation was .26 (n = 140, p = .00) and for HLA DQ5 positive individuals it was .22 (n = 70, p = .07). These results suggest that the distress/immune relationship in genetically susceptible or protected individuals may be underestimated in psychoneuroimmunology research.

Adjuvants, Immunologic↗
PubMed2004

Blood pressure and the cystic fibrosis gene: evidence for lower pressure rises with age in female carriers.

Individuals homozygous for the autosomal recessive disorder CF are known to have low blood pressure, thought to be caused by greatly increased sweat salt loss. We examined whether carriers of the CF gene also have low blood pressure. Our pilot studies had suggested an effect limited to females, leading to 2 further studies in white females. In the first, blood pressure was measured in 232 known CF mutation carriers and compared with 246 mutation-negative control subjects. The carriers showed a significantly lower rate of increase in systolic blood pressure with age than the controls, especially after age 50 (3.5% per decade compared with 5.4% per decade, P=0.010). In a small substudy, sweat sodium and chloride levels were highest in those CF carriers with the lowest blood pressures. In the second study, CF carrier status was investigated in 563 normotensive females and in 607 women with essential hypertension diagnosed to test whether a lower incidence of carriers in the hypertensives suggested a protective effect. Twenty-five of the normotensives (4.4%) were carriers compared with 21 (3.5%) of the hypertensive group (P=0.45). Older CF carrier females had lower systolic and diastolic pressures than matched control subjects, with a tendency for blood pressure to increase less with age. This could result in significant reduction in stroke and heart disease. The effect on blood pressure is insufficient to prevent hypertension, though it remains conceivable that the severity might be ameliorated in carriers.

Adult↗
PubMed2004

Functional identification of AtFao3, a membrane bound long chain alcohol oxidase in Arabidopsis thaliana.

The Arabidopsis thalina genome database was searched for homologues of the Candida cloacae fao1 gene which encodes a membrane bound, flavin-containing, hydrogen peroxide generating, long chain alcohol oxidase. This gene has not been isolated from plants or animals. Four putative candidates were found in the database but their function has not been proven. The cDNAs for two of them were cloned by RT-PCR from Arabidopis suspension culture and one of them [AtFAO3] was overexpressed in Escherichia coli and shown to functionally express long chain alcohol oxidase activity. The protein has been solubilised and retains biological activity thereby preparing the way for crystallographic studies. This is the first functional proof identifying a long chain alcohol oxidase in higher plants.

Alcohol Oxidoreductases↗
PubMed2004

The relationship between distress and the development of a primary immune response to a novel antigen.

Forty-five medical students were recruited to examine the effects of distress on the development of an immune response to the novel antigen, keyhole limpet hemocyanin (KLH). The subjects' level of distress was manipulated by immunizing them either at the time of an important viva voce examination (n=22) or during examination-free term time (n=23). This manipulation increased variance amongst the subjects, but the emphasis in this research was on individual distress as a predictor of immune function. In the group as a whole, the likelihood of developing DTH skin responses to KLH was reduced in the more distressed subjects (r=-.45; p=.002), independently of a number of behavioral (e.g., sleep disturbance) and demographic (e.g., sex) variables. Proliferation of T cells against KLH in vitro and the development of anti-KLH IgG antibodies were not related to levels of distress. Thus, cellular, rather than humoral, immune responses in vivo appear susceptible to the influence of distress. This immunization model provides the opportunity to further dissect the basis of these stress-immune pathways.

Adult↗
PubMed2004

The Eat Well SA project: an evaluation-based case study in building capacity for promoting healthy eating.

The term 'capacity building' is used in the health promotion literature to mean investing in communities, organizations and structures to enhance access to knowledge, skills and resources needed to conduct effective health programs. The Eat Well SA project aimed to increase consumption of healthy food by children, young people and their families in South Australia. The project evaluation demonstrated that awareness about healthy eating among stakeholders across a range of sectors, coalitions and partnerships to promote healthy eating and sustainable programs had been developed. The project achievements were analysed further using a capacity-building framework. This analysis showed that partnership development was a key strategy for success, leading to increased problem-solving capacity among key stakeholders and workers from education, child care, health, transport and food industry sectors. It was also a strategy that required concerted effort and review. New and ongoing programs were initiated and institutionalized within other sectors, notably the child care, vocational education and transport sectors. A model for planning and evaluating nutrition health promotion work is described.

Adolescent↗