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Biomedical subjects

J Hadfield

Publications and source records attributed to J Hadfield.

12 recordsLinked to original sources
PubMed2006

Additional targets of the Arabidopsis autonomous pathway members, FCA and FY.

A central player in the Arabidopsis floral transition is the floral repressor FLC, the MADS-box transcriptional regulator that inhibits the activity of genes required to switch the meristem from vegetative to floral development. One of the many pathways that regulate FLC expression is the autonomous promotion pathway composed of FCA, FY, FLD, FPA, FVE, LD, and FLK. Rather than a hierarchical set of activities the autonomous promotion pathway comprises sub-pathways of genes with different biochemical functions that all share FLC as a target. One sub-pathway involves FCA and FY, which interact to regulate RNA processing of FLC. Several of the identified components (FY, FVE, and FLD) are homologous to yeast and mammalian proteins with rather generic roles in gene regulation. So why do mutations in these genes specifically show a late-flowering phenotype in Arabidopsis? One reason, found during the analysis of fy alleles, is that the mutant alleles identified in flowering screens can be hypomorphic, they still have partial function. A broader role for the autonomous promotion pathway is supported by a microarray analysis which has identified genes mis-regulated in fca mutants, and whose expression is also altered in fy mutants.

Alleles↗
PubMed2004

Evaluation of self-directed clinical education: validation of an instrument.

AIM: To explore the evaluation of self-directed, integrated clinical education. METHODS: We delivered a quantitative and qualitative, self-report questionnaire to students through their web-based learning management system. The questionnaire was distributed 4 times over 1 year, each time in 2 parts. A generic part evaluated boundary conditions for learning, teaching activities and "real patient learning". Factor analysis with varimax rotation was used to validate the constructs that made up the scale and to stimulate hypotheses about how they interrelated. A module-specific part evaluated real patient learning of the subject matter in the curriculum. RESULTS: A total of 101 students gave 380 of a possible 404 responses (94%). The generic data loaded onto 4 factors, corresponding to: firm quality; hospital-based teaching and learning; community and out-patient learning, and problem-based learning (PBL). A 5-item quality index had content, construct and criterion validity. Quality differed greatly between firms. Self-evaluation of module-specific, real patient learning was also valid. It was strongly influenced by the specialty interests of hospital firms. CONCLUSIONS: Quality is a multidimensional construct. Self-report evaluation of real patient learning is feasible, and could be capitalised on to promote reflective self-direction. The social and material context of learning is an important dimension of educational quality.

Clinical Competence↗
PubMed2001

Large-scale mutagenesis directed at specific chromosomes in wheat.

A novel approach has been developed to allow for the efficient selection of loss-of-function wheat mutants in the M1 generation, following either physical or chemical mutagenesis. This has generated an order of magnitude increase in the efficiency of identification of mutants, and also greatly increases the likelihood that selected individuals reflect mutation events at the target locus, rather than at genes acting elsewhere in the disease resistance pathway. The approach relies only on prior knowledge of the chromosomal location of the target gene, and uses the polyploidy of wheat to construct populations for mutagenesis in which large numbers of individuals are hemizygous for the target gene. The idea is illustrated with the mass identification of mutants at three independent genes for race-specific resistance to yellow rust, and one gene for resistance to powdery mildew.

Chromosomes↗
PubMed1980

Studies on the mechanism of shock. Central serotoninergic neuron activity after trauma in the rat.

An attempt has been made to assess the effect of injury (limb ischaemia, scald) on the central serotoninergic system of the rat by studying the effect of these injuries on the tryptophan concentration, the tryptophan hydroxylase activity and the metabolism of serotonin in the hypothalamus, mid-brain and hind-brain. The effects of a serotonin uptake inhibitor and an antagonist on the survival time and mortality rate after limb ischaemia have been examined as well as the effects of central lesions produced by the injection of 5.6- and 5.7-dihydroxytryptamine into a lateral cerebral ventricle and the i.p. injection of (+/-)-4-chloroamphetamine. A few changes indicative of increased activity in the central serotoninergic system were found--an increase in tryptophan hydroxylase activity after 4 h bilateral hind-limb ischaemia, better survival of fed rats pre-treated with 5,6-dihydroxytryptamine--but for the most part the changes were not as great as those produced by starving or exposure to cold. Hence the effect of trauma on this system seems small.

5,6-Dihydroxytryptamine↗
PubMedDate not supplied

Making a difference to practice: clinical benchmarking. Part 1.

In the first of two articles, the authors describe how an internal clinical practice benchmarking group was established in Preston to compare and share examples of best practice. The aim was to ensure consistent high standards of care practice across the trust. Activity related to discharge planning and visiting is used here to illustrate the effectiveness of clinical practice benchmarking as a continuous quality improvement tool. The second article will appear in Nursing Standard on May 3.

Benchmarking↗
PubMedDate not supplied

Making a difference to practice: clinical benchmarking. Part 2.

In the second of two articles, the authors explore further the use of clinical practice benchmarking. In particular, practice related to improving nutritional care for patients, caring for patients with mental health needs and safely transferring critically ill patients is examined. The authors conclude by summarising the value of clinical practice benchmarking and how it made a difference to practice in their trust. The first article appeared in Nursing Standard last week.

Acute Disease↗