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Biomedical subjects

J Draper

Publications and source records attributed to J Draper.

At least 19 recordsLinked to original sources
PubMed2001

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions.

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au+Au collisions at beam energies between 2A and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional Hanburg-Brown-Twiss analysis.

Journal Article↗
PubMed2001

Brachypodium distachyon. A new model system for functional genomics in grasses.

A new model for grass functional genomics is described based on Brachypodium distachyon, which in the evolution of the Pooideae diverged just prior to the clade of "core pooid" genera that contain the majority of important temperate cereals and forage grasses. Diploid ecotypes of B. distachyon (2n = 10) have five easily distinguishable chromosomes that display high levels of chiasma formation at meiosis. The B. distachyon nuclear genome was indistinguishable in size from that of Arabidopsis, making it the simplest genome described in grasses to date. B. distachyon is a self-fertile, inbreeding annual with a life cycle of less than 4 months. These features, coupled with its small size (approximately 20 cm at maturity), lack of seed-head shatter, and undemanding growth requirements should make it amenable to high-throughput genetics and mutant screens. Immature embryos exhibited a high capacity for plant regeneration via somatic embryogenesis. Regenerated plants display very low levels of albinism and have normal fertility. A simple transformation system has been developed based on microprojectile bombardment of embryogenic callus and hygromycin selection. Selected B. distachyon ecotypes were resistant to all tested cereal-adapted Blumeria graminis species and cereal brown rusts (Puccinia reconditia). In contrast, different ecotypes displayed resistance or disease symptoms following challenge with the rice blast pathogen (Magnaporthe grisea) and wheat/barley yellow stripe rusts (Puccinia striformis). Despite its small stature, B. distachyon has large seeds that should prove useful for studies on grain filling. Such biological characteristics represent important traits for study in temperate cereals.

Anti-Bacterial Agents↗
PubMed2000

Sideward flow in Au+Au collisions between 2A and 8A GeV

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Journal Article↗
PubMed2000

A loss of resistance to avirulent bacterial pathogens in tobacco is associated with the attenuation of a salicylic acid-potentiated oxidative burst.

The role of salicylic acid (SA) in events occurring before cell death during the hypersensitive reaction (HR) was investigated in leaves of wild-type tobacco Samsun NN and in transgenic lines expressing salicylate hydroxylase (35S-SH-L). Challenge of 35S-SH-L tobacco with avirulent strains of Pseudomonas syringae gave rise to symptoms resembling those normally associated with a compatible response to virulent strains in terms of visible phenotype, kinetics of bacterial multiplication, and escape from the infection site. Compared with responses in wild-type tobacco, both the onset of plant cell death and the induction of an active oxygen species-responsive promoter (AoPR1-GUS) were delayed following challenge of 35S-SH-L plants with avirulent bacteria. The oxidative burst occurring after challenge with avirulent bacteria was visualized histochemically and quantified in situ. H2O2 accumulation at reaction sites was evident within 1 h after inoculation in wild-type tobacco, whereas in 35S-SH-L plants the onset of H2O2 accumulation was delayed by 2-3 h. The delay in H2O2 generation was correlated with a reduction in the transient rise in SA that usually occurred within 1-2 h following inoculation in wild-type plants. Our data indicate that an early transient rise in SA potentiates the oxidative burst, with resultant effects on accumulation of H2O2, plant cell death and also defence-gene induction, factors that together may determine the outcome of plant-pathogen interactions.

Hydrogen Peroxide↗
PubMed1997

Whose welfare in the labour room? A discussion of the increasing trend of fathers' birth attendance.

OBJECTIVE: To review the key literature on fathers' birth attendance, discussing: factors contributing to the increasing trend in men's birth attendance; the different roles and responsibilities men may adopt in the labour room and the implications; and, particularly, the education needs of both the expectant fathers and the professionals. LITERATURE SEARCH: The literature reported here is part of a larger longitudinal ethnographic study of men's experiences of pregnancy and birth, which to date has generated 190 relevant articles. The literature was identified using: the Midwifery Information Resource Service (MIDIRS), PsychLit, Cinahl, Medline, and the Cochrane Pregnancy and Childbirth Database. Keywords were: men, fathers, pregnancy, birth, and birth supporters. Literature was also identified using references quoted in papers and hand searching of journals. KEY CONCLUSIONS: Changing cultural and professional attitudes have encouraged fathers' birth attendance, reflected in an increasing volume of research. This research concentrates almost exclusively on labour coaching roles, neglecting exploration of any independent needs men may have. IMPLICATIONS FOR PRACTICE: A greater awareness of men's experiences will inform midwives and childbirth educators to effectively provide for men's needs during pregnancy and birth.

Attitude to Health↗
PubMed1997

Alternative processing of the maize Ac transcript in Arabidopsis.

The successful application of the maize transposable element system Ac/Ds as a genome mutagen in heterologous plant species has recently proved the versatility and power of this technique in plant molecular biology. However, the frequency of Ac/Ds transposition is considerably lower in Arabidopsis thaliana than in most other dicot plant species that have been studied. Since previous research has established that transcripts derived from monocot genes can be alternatively processed in dicot plants, we have investigated both the efficiency of intron splicing and polyadenylation of the maize Ac transposase pre-mRNA in Arabidopsis thaliana, Nicotiana tabacum, Nicotiana plumbaginifolia and Zea mays. In this paper, we demonstrate that intron 4 is alternatively spliced within Arabidopsis, using cryptic 5' and 3'splice sites within the intron sequence, leading to a heterogeneous population of full length of transposase transcript. Furthermore, analysis of transposase transcript polyadenylation revealed that at least four alternative poly(A) sites were utilized between introns 2 and 3, resulting in truncated transposase transcripts. Finally, by Northern blotting, we established that the truncated transposase transcript was the most abundant form of transposase message in Arabidopsis. In contrast to these findings, the alternative splicing and premature polyadenylation of Ac message in Arabidopsis was unparalleled in the other species examined. We suggest that the poor frequency of transposition of Ac in Arabidopsis may be in part due to the low quantity of correctly processed transposase transcript available in this species.

Alternative Splicing↗
PubMed1997

Compromising early salicylic acid accumulation delays the hypersensitive response and increases viral dispersal during lesion establishment in TMV-infected tobacco.

To investigate the role of salicylic acid (SA) in the hypersensitive response (HR) its accumulation was compromised during different phases of lesion development by differential expression of a salicylate hydroxylase gene (SH-L). Constitutive suppression of SA accumulation was achieved by expression of a gene fusion between the CaMV35S promoter (35S) and SH-L. Using the H2O2-responsive AoPR1 promoter to drive SH-L SA accumulation could be compromised at an early stage, on lesion formation and possibly prior to visible necrosis, whilst use of the salicylate-responsive PR1a promoter reduced SA accumulation at a later stage as lesions expand. TMV infection of 35S-SH-L and AoPR1-SH-L, but not PR1a-SH-L, tobacco resulted in significantly greater rates of lesion growth than in wild-type tobacco. TMV was detected in asymptomatic tissue surrounding lesions only in 35S-SH-L and AoPR1-SH-L lines; subsequently these transgenic lines exhibited a 'spreading-necrosis' originating from the lesion which entered the stem and eventually other leaves, a phenotype which could be correlated with the presence of TMV particles. Analysis of TMV-infected and 'temperature-shifted' tobacco indicated that both 35S-SH-L and AoPR1-SH-L, but not PR1a-SH-L, transgenics exhibited delayed cell-death compared to wild-type infections. We propose that the SH-L phenotypes indicate that early SA accumulation is a major factor in preventing viral escape, via mechanism(s) which may include influencing the rate of host-cell death and, possibly, an effect on viral function.

Artificial Gene Fusion↗
PubMed1996

A discussion of some of the literature relating to history, repair and consequences of perineal trauma.

OBJECTIVE: to review the key literature on perineal trauma, discussing the historical background, the materials and techniques used, the possible consequences of repair and assess midwives' current and potential contribution to perineal repair. LITERATURE SEARCH: the literature was identified using conventional search techniques: Midwifery Information Resource Service (MIDIRS) and the Cochrane Pregnancy and Childbirth Database. Keywords used during the search were: episiotomy, perineal trauma and adverse effects. Associated keywords words were sexuality, pain and psychology. KEY CONCLUSIONS: current practice in the UK is inconsistent with the available evidence, perineal trauma can cause long term problems, and midwives are in an ideal position to take forward evidence-based perineal repair. IMPLICATIONS FOR PRACTICE: midwives need adequate education and training in perineal repair but are likely to be more effective in performing the repair. Systematic evaluation of the impact of extending midwives' influence in this area is essential.

Episiotomy↗
PubMed1996

An investigation into the application and maintenance of Hamilton Russell traction on three orthopaedic wards.

This study is concerned with the application and maintenance of Hamilton Russell traction, a form of vectored skin traction. It may be used in the treatment of fractures of the femur for the purposes of immobilization and for pain relief prior to surgery. A preliminary questionnaire demonstrated a poor level of knowledge in nurses working in an orthopaedic area. It was therefore speculated that application and maintenance of the traction would be inaccurate. The angles making up the resultant traction forces were measured in 11 systems. The theoretical traction force was established using mathematics. The actual force was measured using a goniometer. A comparison was then made. The results in all 11 systems demonstrated a highly statistically significant difference between the theoretical and actual positions of the traction force (P < 0.0005). The practical implications of this are discussed and recommendations for a protocol of application and maintenance suggested. Areas for further research are identified.

Biomechanical Phenomena↗
PubMed1996

Nursing development units: an opportunity for evaluation.

The nursing development unit movement has recently generated a lot of financial and professional interest. This is demonstrated by the large financial investment by the Department of Health, England, and the growing number of papers in the nursing literature. The benefits of these units, however, are not as well documented. This paper seeks to contribute to the debate by: reviewing some of this literature and putting the movement in a historical perspective; discussing the purposes of the units; critically examining the characteristics of such units; evaluating their effectiveness; and suggesting a way forward for the future.

Clinical Nursing Research↗
PubMed1995

Hydrogen peroxide does not function downstream of salicylic acid in the induction of PR protein expression.

The roles of salicylic acid (SA) and H2O2 in the induction of PR proteins in tobacco have been examined. Studies were conducted on wild-type tobacco and plants engineered to express a bacterial salicylate hydroxylase capable of metabolizing SA to catechol (SH-L plants). Wild-type and PR-1a-GUS-transformed plants express PR-1a following challenge with Pseudomonas syringae pathovar syringae, SA or 2,6-dichloro-isonicotinic acid (INA). In contrast, SH-L plants failed to respond to SA but did express PR-1a following INA treatment. H2O2 and the irreversible catalase inhibitor 3-amino-1,2,4-triazole (3-AT) were found to be weak inducers of PR-1a expression (relative to SA) in wild-type tobacco but were unable to induce PR-1a in SH-L plants, suggesting that the action of these compounds depends upon the accumulation of SA. A model has been proposed suggesting that SA binds to and inhibits a catalase inducing an increase in H2O2 leading to PR protein expression. Catalase activity has been measured in tobacco and no significant changes in activity following infection with P. syringae pv. syringae were detected. Furthermore, inhibition of catalase activity in vitro in plant extracts requires pre-incubation and only occurs at SA concentrations above 250 microM. Leaf disks preincubated with 1 mM SA do accumulate SA to these levels and PR-1a is efficiently induced but there is no apparent inhibition of catalase activity. It is also shown that a SA-responsive gene, PR-1a, and a H2O2-sensitive gene, AoPR-1, are both relatively insensitive to 3-AT suggesting that induction of these genes is unlikely to be due entirely to inhibition of an endogenous catalase.

Amitrole↗
PubMed1995

Risk factors for recurrent emergency department visits for asthma.

BACKGROUND: Patients presenting with asthma to emergency departments have lost control of their disease, have significant airways obstruction, and frequently require admission to hospital. Although even one visit is not desirable, there is a more disturbing subgroup who repeatedly visit the emergency department. METHODS: To investigate the reasons for multiple emergency visits, a questionnaire was given to 448 consecutive patients presenting to the two largest adult emergency departments in Ottawa, Canada between November 1989 and April 1991. Within this cohort, those who had made at least three visits in the past year were compared with controls (only one visit in the past year). RESULTS: Although inhaled corticosteroid use increased with multiple visits (indicating increased asthma severity), only 60% of those visiting at least three times in the past year were taking inhaled corticosteroids. Chronic undermedication relative to disease severity was apparent among the cases. The number of visits was associated with nocturnal asthma on a regular basis, work and school absenteeism, frequent visits to their regular physician, and frequent admissions to hospital. Visits were not related to psychological health, environmental allergens/irritants, or lack of perceived asthma severity. CONCLUSIONS: The recommendations of current asthma guidelines are not reaching these patients. The issue of translating guidelines from paper to practice must be addressed before highly effective medications can have an important impact on the frequency of emergency department visits.

Adrenal Cortex Hormones↗
PubMed1994

Endoplasmic reticulum targeting of active modified beta-glucuronidase (GUS) in transgenic tobacco plants.

We have investigated targeting to the endoplasmic reticulum (ER) of wild-type GUS and a modified form (GUS S358) by making an N-terminal fusion of the beta-glucuronidase (GUS) enzyme with the wheat alpha-amylase signal peptide. In vitro studies demonstrated that the modified GUS (S358) lacked the glycosylation site present within the wild-type enzyme. Analysis of transgenic tobacco plants revealed that the modified GUS enzyme retained activity upon passage to the ER. When further experiments were carried out to determine the cellular location of the modified GUS enzyme, it was found that (contrary to expectation) the majority of GUS activity was retained within the cell and was not secreted to the cell surface via the default pathway. The data indicated that the modified GUS enzyme is an unsuitable reporter enzyme for studying protein secretion.

Amino Acid Sequence↗