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Biomedical subjects

C Cairns

Publications and source records attributed to C Cairns.

At least 19 recordsLinked to original sources
PubMed2000

Computer education. Don't forget the older GPs.

OBJECTIVE: To implement and evaluate a computer education and support program for GPs. METHODS: A 'hands-on' curriculum, based on small group learning in a clinical computing laboratory and supported via the Internet, was developed and implemented. Evaluation was threefold: observations during lessons; interviews; and participants completing a questionnaire before and six months after the course. A randomly selected group of GPs from the same region completed a modified version of the 'before' questionnaire at the same time as participating GPs were completing their six month questionnaire. Participants included 128 GPs in a computer education program in Victoria (Australia) plus 127 'control' GPs. Outcome measures were self reported computing skill, attitudes to and actual use of clinical applications. RESULTS: Six months after training, there was a significant increase in self reported computer skill (p < 0.01). Multivariate regression found that, after controlling for gender, practice characteristics, and previous training, the older (> 55 years) GPs reported greater change in their skills than their younger colleagues. The increased skill happened regardless of which or how many modules were completed, and included use of email, the Internet, computers for research and electronic prescribing. Awareness of relevant computer applications, confidence with computers and intention to use applications also increased. Participants found the dedicated clinical computing laboratory useful; however, there are significant issues with maintenance and keeping systems up-to-date. CONCLUSIONS: The computer education and support program was relevant to GP needs, deliverable and effective in improving skills and utilisation. Divisions and other GP organisations should be assisted to establish similar education and support programs and, perhaps, target older doctors.

Adult↗
PubMed1998

Implementation of sequential therapy programmes--a pharmacist's view.

Sequential antibiotic therapy has a number of advantages in terms of patient benefit and value for money in drug use. Introduction and maintenance of a process to ensure sequential therapy is multidisciplinary, involving clinicians, pharmacists, microbiologists and possibly nurses. The contribution of pharmacists is multi-faceted and involves senior and junior pharmacists working in a number of areas. Pharmacy managers will be involved at policy setting level through the Drug and Therapeutics committee and similar bodies. Purchasing and formulary pharmacists will be involved in negotiating purchasing agreements while clinical pharmacists provide data on the costs and outcomes of treatment. The drug information pharmacist is a valuable resource in searching and interpreting the available literature. Whatever system is used, clinical pharmacists have an important role in identifying patients and monitoring prescribing. In many schemes described in the literature, pharmacists have had an important role in auditing the effectiveness of sequential therapy. There may be scope for developing the clinical pharmacist's role further by devolving, under protocol, increased decision making and medicines management responsibilities.

Administration, Oral↗
PubMed1998

Effects of food, glucose, and water ingestion on feeding activity in the toad (Bufo bufo).

Feeding in toads was tested by orient, approach, fixate, and snap responses to an artificial prey stimulus, before and at various times after feeding with natural prey (mealworms), or infusion of the gut with a prey-equivalent amount of glucose or volume of water. Feeding 5 prey objects or ad libitum feeding caused a decline in a prey catching when tested 2 hr later. Ingestion of 5 pulped mealworms or the equivalent glucose content and volume similarly decreased prey-catching, though an equal volume of water had no effect. Comparisons of the effect of time after glucose ingestion on prey-catching activity demonstrated that the major decline in activity occurred within 15 min, with no appreciable change after 2 hr. An equal volume of water had little effect on prey-catching activity over 15 min, but subsequent glucose ingestion reduced these behaviors. Thus, the decline in prey catching that occurs after feeding in toads can be rapidly replicated by ingestion of glucose, allowing future examination of the neural basis of satiety in these animals.

Analysis of Variance↗
PubMed1997

Promoter-dependent synergy between glucocorticoid receptor and Stat5 in the activation of beta-casein gene transcription.

Steroid hormone receptors and Stat factors comprise two distinct families of inducible transcription factors. Activation of a member of each family, namely the glucocorticoid receptor by glucocorticoids and Stat5 by prolactin, is required for the efficient induction of the expression of milk protein genes in the mammary epithelium. We have studied the mode of interaction between Stat5 and the glucocorticoid receptor in the activation of beta-casein gene transcription. The functional role of potential half-palindromic glucocorticoid receptor-binding sites mapped previously in the promoter region was investigated. beta-Casein gene promoter chloramphenicol acetyltransferase constructs containing mutations and deletions in these sites were tested for their responsiveness to the synergistic effect of prolactin and dexamethasone employing COS-7 cells or HC11 mammary epithelial cells. Synergism depended on promoter regions containing intact binding sites for the glucocorticoid receptor and Stat5. The carboxyl-terminal transactivation domains of Stat5a and Stat5b were not required for this synergism. Our results suggest that in lactogenic hormone response elements glucocorticoid receptor molecules bound to nonclassical half-palindromic sites gain competence as transcriptional activators by the interaction with Stat5 molecules binding to vicinal sites.

Animals↗
PubMed1997

The Xenopus RNA polymerase I transcription factor, UBF, has a role in transcriptional enhancement distinct from that at the promoter.

Repeated sequence elements found upstream of the ribosomal gene promoter in Xenopus function as RNA polymerase I-specific transcriptional enhancers. Here we describe an in vitro system in which these enhancers function in many respects as in vivo. The principal requirement for enhancer function in vitro is the presence of a high concentration of upstream binding factor (UBF). This system is utilized to demonstrate that enhancers function by increasing the probability of a stable transcription complex forming on the adjacent promoter. Species differences in UBF are utilized to demonstrate that enhancers do not act by recruiting UBF to the promoter, rather UBF performs its own distinct role at the enhancers. UBF function in enhancement differs from that at the promoter, as it is flexible with respect to both the species of UBF and the enhancer element employed. Additionally, we identify a potential role for the mammalian UBF splice variant, UBF2, in enhancer function. We demonstrate that the TATA box binding protein (TBP)-containing component of Xenopus RNA polymerase I transcription, Rib1, can interact with an enhancer-UBF complex. This suggests a model in which enhancers act by recruiting Rib1 to the promoter.

Animals↗
PubMed1996

Upstream binding factor stabilizes Rib 1, the TATA-binding-protein-containing Xenopus laevis RNA polymerase I transcription factor, by multiple protein interactions in a DNA-independent manner.

Initiation of RNA polymerase I transcription in Xenopus laevis requires Rib 1 and upstream binding factor (UBF). UBF and Rib 1 combine to form a stable transcription complex on the Xenopus ribosomal gene promoter. Here we show that Rib 1 comprises TATA-binding protein (TBP) and TBP-associated factor components. Thus, Rib 1 is the Xenopus equivalent of mammalian SL 1. In contrast to SL 1, Rib 1 is an unstable complex that readily dissociates into TBP and associated components. We identify a novel function for UBF in stabilizing Rib 1 by multiple protein interactions. This stabilization occurs in solution in a DNA-independent manner. These results may partially explain the difference in UBF requirement between Xenopus and mammalian systems.

Amino Acid Sequence↗
PubMed1995

HMG box 4 is the principal determinant of species specificity in the RNA polymerase I transcription factor UBF.

Transcription of ribosomal genes requires, in addition to RNA polymerase I, the trans-acting factors UBF and Rib1 in Xenopus or SL1 in humans. RNA polymerase I transcription is remarkably species specific. Between closely related species SL1 is the sole determinant of this specificity. Between more distantly related species, however, UBF is also a component of this species specificity. Xenopus UBF cannot function in human RNA polymerase I transcription and human UBF cannot function in Xenopus RNA polymerase I transcription. Xenopus and human UBFs are remarkably similar at the amino acid sequence level, both containing multiple HMG box DNA binding motifs. The only major difference between xUBF and hUBF is the lack of a HMG box 4 equivalent in xUBF. Utilizing a series of hybrid UBF molecules we have identified HMG box 4 as the principal determinant of species specificity. Addition of human HMG box 4 to xUBF converts it to a form that functions in human RNA polymerase I transcription. Deletion of HMG box 4 from hUBF converts it to a form that functions in Xenopus RNA polymerase I transcription. Furthermore, mutations within Xenopus UBF demonstrate that UBF requires a precise arrangement and number of HMG boxes to function in RNA polymerase I transcription.

Animals↗
PubMed1995

Efficacy of tissue glue for laceration repair in an animal model.

OBJECTIVE: To compare the efficacy of butyl-2-cyanoacrylate tissue glue (TG) for the repair of skin lacerations in rats with the efficacy of standard closure with sutures. METHODS: In a prospective study, eight rats were anesthetized and an 8-cm dorsal incision was made on each side of the midline. One wound was closed with a single layer of interrupted 5-0 Prolene suture and one by application of TG. The time required to close each wound was recorded. Sutures were removed at seven days; the TG was allowed to fall off spontaneously. The animals were sacrificed after 20 days and the wounds were judged for cosmetic outcome. Four I x 3-cm strips of skin were excised from each wound; one strip for histologic analysis and three for load extension testing using a tensiometer. Specimens were loaded to wound failure while displacement (D) and energy absorption (EA) were recorded. The paired t-test was used for comparisons and reported as mean +/- SE. No significant difference between TG and suture was found in D (6.5 +/- 0.4 vs 5.2 (1.4 mm), EA (0.18 +/- 0.01 vs 0.17 +/- 0.03 kg x mm/cm2), or histologic features. The closure time was significantly less using TG (66 +/- 5 vs 401 +/- 17 sec; p < 0.0001). CONCLUSIONS: 1) Sutures and TG in rat skin repair result in similar wound strengths (EA), amounts of stretch (D), and histologic feasures. 2) Wound closure is accomplished much more rapidly with TG.

Animals↗
PubMed1995

Identification and cDNA cloning of a Xenopus nucleolar phosphoprotein, xNopp180, that is the homolog of the rat nucleolar protein Nopp140.

The monoclonal antibody G1C7, recognises both Xenopus nucleolin and a protein of 180 kDa present in Xenopus oocyte nucleoli. This antibody was used to obtain a cDNA clone encoding the 180 kDa protein now called xNopp180 (Xenopus nucleolar phosphoprotein of 180 kDa). Analysis of the deduced amino acid sequence from this cDNA shows that xNopp180 is almost entirely composed of alternating acidic and basic domains. We show that xNopp180 is heavily phosphorylated and that it contains multiple consensus sites for phosphorylation by casein kinase II and cdc2 kinase. In addition we show that xNopp180 is the 180 kDa antigen recognised by the monoclonal antibody No-114, thus allowing reinterpretation of previous work with this antibody. xNopp180 appears to be the Xenopus homolog of the rat nucleolar protein Nopp140. Nopp140 is a nuclear localisation signal binding protein that shuttles on curvilinear tracks between the nucleolus and the cytoplasm. Possible roles for xNopp180/Nopp140 in ribosome biogenesis are discussed.

Amino Acid Sequence↗
PubMed1993

Thermodynamics of the glucocorticoid receptor-DNA interaction: binding of wild-type GR DBD to different response elements.

We used fluorescence spectroscopy to study the chemical equilibria between an 82-residue protein fragment containing the core conserved region of the glucocorticoid receptor DNA-binding domain (GR DBD) and a palindromic glucocorticoid response element (GRE), a consensus GRE half-site, a consensus estrogen response element (ERE) half-site, and two intermediate half-sites (GRE2 and ERE2). Equilibrium parameters were determined at 20 degrees C and buffer conditions that approximate intracellular conditions. The association constants for GR DBD binding to the GRE (5'TGTTCT3') and GRE2 (5'TGTCCT3') half-sites at 85 mM NaCl, 100 mM KCl, 2 mM MgCl2, and 20 mM Tris-HCl at pH 7.4 and low concentrations of an antioxidant and a nonionic detergent are (1.0 +/- 0.1) x 10(6) M-1 and (5.1 +/- 0.2) x 10(5) M-1, respectively. The association constants for binding to the ERE (5'TGACCT3') and ERE2 (5'TGATCT3') half-sites are < 10(5) M-1. The implications of these numbers for the specificity and affinity for the binding of the intact GR to DNA are discussed. Comparison of GR DBD binding to a GRE half-site and a palindromic GRE sequence allowed us to estimate the cooperativity parameter, omega obs = 25-50, for GR DBD binding to GRE. The thermodynamics of the GR DBD interaction with a GRE half-site were also investigated by determining the temperature dependence of the observed association constant. The nonlinear dependence in ln Kobs as a function of 1/T is consistent with a change in standard heat capacity, delta Cp degree obs = 1.0 +/- 0.2 kcal mol-1 K-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1993

Glucocorticoid receptor binding sites in the promoter region of milk protein genes.

The action of glucocorticoids on the induction of the two milk protein genes beta-casein and whey acidic protein (WAP) is delayed and appears to be indirect. The response requires a co-stimulation of cells with prolactin, is restricted to mammary epithelial cells and is dependent on cis-acting sequences localized in the promoter region of the two genes. We have searched for glucocorticoid receptor (GR) binding sites in these hormone response regions. In vitro DNaseI footprinting experiments were performed with a purified preparation of the GR from rat liver. The sequences between -231 and -7 and between -250 and -79 of mouse WAP and rat beta-casein gene promoter, respectively, were found to contain multiple sites which were protected from the attack of DNaseI by the GR preparation. The sites comprise sequence motifs related to the delayed secondary glucocorticoid response elements described (Chan et al., J. Biol. Chem. 266, 22,634-22,644, 1991), which represent half sites of classical GR binding sites. In the WAP gene promoter, the motifs are arranged head to tail with irregular spacing. The GR binding sites are in close proximity or even overlap with the bindings sites for candidate factors involved in mammary cell specific gene expression. The results suggest a direct co-operation between GR and mammary cell specific transcription factors in mediating the expression of milk protein genes.

Animals↗
PubMed1993

Inhibition of gene expression by steroid hormone receptors via a negative glucocorticoid response element: evidence for the involvement of DNA-binding and agonistic effects of the antiglucocorticoid/antiprogestin RU486.

We have used a negative glucocorticoid response element (nGRE) from the bovine prolactin promoter linked to the gene for chloramphenicol acetyltransferase (PRL3CAT) to study the inhibition of gene expression by steroid hormone receptors. This nGRE increased basal expression from a heterologous promoter in COS-7 cells. In the presence of cotransfected glucocorticoid (GR), androgen, or progesterone receptor (PR) expression vectors and their cognate ligands, the expression of PRL3CAT could be repressed, indicating that these steroid receptor subfamily members could function through the same negative response element. No repression was observed with the estrogen receptor, showing that the repressive effect was specific for members of the GR-subfamily. Mutation of three amino acids within the GR-DNA binding domain that determine the specificity of GR-GRE interaction abolished the ability of the GR to inhibit the expression of PRL3CAT, demonstrating the requirement for DNA binding of the GR in the mechanism of repression. The antiglucocorticoid/antiprogestin RU486 when bound to PR or GR also repressed the expression of the PRL3CAT, but higher concentrations of RU486 were required to obtain an effect with the GR when compared to the PR. RU486 was unable to antagonize the effect of progestins on PRL3CAT and only partially antagonized the glucocorticoid repression. Thus, regarding the repression of PRL3CAT, RU486 acted as an agonist when bound to the PR and as a partial agonist when bound to the GR.

Amino Acid Sequence↗
PubMed1991

Assembly of a glucocorticoid receptor complex prior to DNA binding enhances its specific interaction with a glucocorticoid response element.

Gel retardation analysis with full- and half-palindromic sequences using partially purified glucocorticoid receptor (GR) resulted in GR-glucocorticoid response element (GRE) species of identical mobilities, suggesting that formation of the dimeric GR protein complex is not catalyzed by DNA binding. These results are in contrast to the behavior of the isolated DNA binding domain of the glucocorticoid receptor where dimerization occurred on the GRE. Density gradient centrifugation of cytosolic GR resulted in two forms, a 4 S peak characteristic of the monomeric GR and a fraction which sediments at 6 S which is consistent with the observed size of the dimeric GR. These two forms were found to differ in their ability to bind to specific DNA sequences with the 6 S species having a higher affinity for a GRE. Taken together our results are consistent with a two-step model for hormone-induced transformation of GR: dissociation of the multimeric untransformed complex and dimerization of the GR to yield a high affinity DNA binding species.

Animals↗
PubMed1991

Identification of protein contact sites within the glucocorticoid/progestin response element.

The glucocorticoid receptor (GR) and the progestin receptor (PR) bind specifically to a variety of DNA sequences, glucocorticoid/progestin response elements (GRE/PRE), located in the proximity of responsive gene promoters. Using the isolated recombinant GR DNA-binding domain (DBD), it has recently been shown that GR interacts with the GRE/PRE, a 15-basepair partially palindromic consensus sequence, as a dimer. In this study an investigation into the GR-GRE/PRE and PR-GRE/PRE interaction has been performed using missing base contact analysis with the tyrosine aminotransferase GREII (TATII) and recombinant GR DBD as well as a fusion protein consisting of the PR DBD fused to Staph. aureus protein-A. GR and PR had identical base contact points, localized within two consecutive major grooves, binding to the same face of the DNA. Ethylation interference was also performed on the GR DBD-TATII interaction. The contact points with the backbone phosphate groups flank the contacts within the major groove for each of the two half-sites. Knowledge of the contact points within the DNA sequence together with the three-dimensional structure of the protein enables modelling of the protein-DNA interaction.

Base Sequence↗
PubMed1985

Near infrared spectrophotometry: potential role during increased intracranial pressure.

Two experiments were conducted to assess the feasibility of near infrared spectrophotometry (niroscopy) to directly monitor the effects of increased intracranial pressure on brain metabolism. Intracranial pressure (ICP) was increased in cats by subarachnoid infusion of a "mock" CSF solution. Cytochrome a,a3 redox state, oxyhemoglobin, deoxyhemoglobin and cerebral blood flow were non-invasively and continuously monitored by niroscopy. The results of both experiments indicated that untreated increases in ICP correlated with a reduction in cytochrome a,a3 redox state (p less than 0.01), a decrease in the quantity of oxyhemoglobin and cerebral blood flow (p less than 0.01), and an increase in deoxyhemoglobin. This study suggests that niroscopy has the potential for providing noninvasively and continuously data assessing brain metabolic activity. The excellent correlations obtained with simultaneous direct measurements of intracranial pressure make this an attractive method for eventual application to humans at risk for increased intracranial pressure. The value of niroscopy is even more evident in Exp. II where it can be seen that knowledge only of ICP would give the physician a false sense of security, whereas direct, non-invasive, continuous assessment of brain perfusion and oxygenation may well prove to be more appropriate parameters to monitor.

Animals↗
PubMed1984

Brain metabolism during increased intracranial pressure as assessed by niroscopy.

Intracranial pressure was increased in cats by infusion of "mock" cerebrospinal fluid into the cisterna magna. This condition was then treated by hyperventilation. In addition to direct measurement of intracranial pressure, cerebral metabolism was assessed by near infrared spectrophotometric (niroscopic) measurement of cytochrome a,a3 redox state and the quantity of reduced and oxygenated hemoglobin in the illuminated brain. Cerebral perfusion was assessed by injection of Cardio-Green. Increased intracranial pressure resulted in the expected reduction in cytochrome a,a3,a decrease in HbO2, an increase in Hb, and a reduction of blood flow. The vasoconstriction produced by hyperventilation, while reducing intracranial pressure, produced a further reduction in cytochrome a,a3 and HbO2, with no improvement in blood flow. The data illustrate the fallacy of governing therapy solely by intracranial pressure and demonstrate the need for a direct assessment of brain metabolism. The data also demonstrate the strengths and weaknesses of niroscopy as a noninvasive monitor of the brain metabolism if applied to patients at risk for increased intracranial pressure.

Animals↗