bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methotrexate therapy in asthma increases T cell susceptibility to corticosteroid inhibition
Authors: Corrigan C. J. , Shiner R. , Shakur B. H. , Ind P. W. 
Published: August 2003

AbstractBackground  Concomitant methotrexate (MTX) therapy of severe, oral corticosteroid‐dependent asthmatics has been shown to be corticosteroid sparing, but the mechanism is unknown. We hypothesized that MTX therapy of these patients increases the susceptibility of their T cells to corticosteroid inhibition.Objective  To measure prednisolone inhibition of lectin‐induced proliferation of peripheral blood T cells from a group of these patients before, during and following MTX therapy.Methods  Eighteen severe asthmatics (median (range) age 56 (33–68) years, FEV1 61 (38–69)% predicted, dependent on oral prednisolone 15 (7.5–25) mg/day in addition to high‐dose, inhaled corticosteroids) were treated with MTX 15 mg intramuscularly, weekly for 28 weeks. After 12 weeks of MTX, oral prednisolone dosages were reduced systematically over 16 weeks, provided that asthma control did not deteriorate. Patients were followed for a further 12 weeks after MTX withdrawal. Concentration‐dependent, prednisolone inhibition of lectin‐induced proliferation of peripheral blood T cells was measured just prior to MTX therapy (week 1) and at weeks 12, 28 and 40, and IC50 concentrations were interpolated.Results  By week 28 of MTX therapy, patients were able to reduce oral prednisolone dosages from (median, SIQR) 15 (10–20.5) to 5.9 (1.4–9.4) mg/day (P<0.01) without alteration of lung function and symptoms, while median IC50 values for prednisolone inhibition of peripheral blood T cell proliferation were reduced from 49 (21–144) to 4 (1–9) nm (P<0.0001). These increased again to 15 (9.4–25.7) mg/day and 36 (18–67) nm, respectively, following MTX withdrawal. A correlation (P<0.01) was observed between percentage reductions in prednisolone dosages in vivo and fold changes in prednisolone IC50in vitro between weeks 12 and 28.Conclusion  This effect of MTX may at least partly account for its oral corticosteroid‐sparing effect in severe asthma.
Parents' perceptions of staff competency in a neonatal intensive care unit
Authors: Cescutti‐Butler Luisa , Galvin Kathleen 
Published: August 2003

Summary• The aim of this study was to explore and describe parents' perceptions of staff competency in a neonatal intensive care unit (NICU). The study set out to use a grounded theory approach that was modified because of a number of constraints. Eight parents whose babies met a number of inclusion criteria were interviewed using focused conversational interviews. They were then transcribed and thematically analysed. The research approach was modified as the study developed because of practical and ethical access reasons: the sampling strategy and lack of opportunity to exploit fully the constant comparative method.• Four key themes which conceptualize competency as caring emerged from the data: parents are facilitated to integrate into the unit and do not feel a burden; parents feel in control whilst in the unit; parents have a choice to opt out from observing tasks and procedures on their baby; parents and the interprofessional team communicate well and provide appropriate information. These are discussed in the context of available literature.• In conclusion, the results of the study serve to highlight how parents' perceptions of competence in a professional are not based solely on skills and tasks but on many caring behaviours. The grounded theory approach has generated a number of areas for exploration, in particular, ideas about the conceptual basis of caring in an NICU context and its links to competence. The caring behaviours involve learning to share responsibility with families. The findings suggest that when there is ‘a handing over’ of control to parents and a greater emphasis on parent support, they feel less like ‘guests’. These ideas are supported by the available literature. A number of methodological issues are raised.
Multidisciplinary nursing: re‐thinking role boundaries
Authors: Pearson Alan 
Published: August 2003

Summary• The ambiguous role of nurses within the health care team has been a subject of much debate, evident in current practice and the study of the early development of nursing in Australia.• Early nursing work was broad and uncontested. Debates about nursing and ‘non‐nursing’ tasks are thought to have emerged after the establishment of ‘Nightingale reforms’ in the 1870s.• Nursing role conflicts may be due in part to the rise in technology and medical intervention, the demise of ‘generalist’ doctors, nurses and patient‐centred care, the creation of nursing specialists who moved to other community care positions and nursing's drive for professionalization.• Nurses’ role in mealtimes provides one example of the ambiguous and contentious issue of nursing and non‐nursing work.• Health services need a generic worker who is client‐focused, possesses multidisciplinary skills, manages the care environment, humanizes the system at the point of contact and acts therapeutically. This broad and flexible role ascribed to nurses is threatened by cost containment and the scramble for new occupations within the broad field of health services, which is plagued with increasingly rigid role boundaries.• The examination of nursing workforce planning arrangements is needed to ensure greater coherence and clearer lines of nurses’ roles and responsibilities.
Children's nursing: can it justify a separate existence in the UK?
Authors: Lee Polly 
Published: August 2003

Summary• There is currently debate about how the professional register for nurses is organized in the UK. Children's nurses, like the other minority registrants of mental health and learning disabilities nurses felt threatened with the potential loss of a separate register.• Children's nurses should be able to articulate their own unique body of knowledge.• Using Fawcett's framework for the hierarchy of contemporary nursing knowledge, the development of children's nursing knowledge is examined to determine if, indeed, children's nursing is a separate discipline, by having its own metaparadigm of children's nursing, philosophy, conceptual model of nursing, nursing theories and, finally, empirical indicators.• Although some levels of knowledge appear to have been developed, it is considered that children's nursing is still lacking in some levels of knowledge, thus suggesting that the continuing development of children's nursing knowledge is necessary.
Pharmacological assessment of the role of nitric oxide in mice infected with lethal and nonlethal species of malaria
Authors: Dascombe Michael J. , Nahrevanian Hossein 
Published: August 2003

SUMMARY This pharmacological investigation sought to determine whether nitric oxide (NO) had an antiparasitic effect and/or mediated pathology in mice infected with nonlethal P. chabaudi or lethal P. berghei. Nitric oxide synthase (NOS) inhibitors were evaluated for their ability to inhibit the rise in reactive nitrogen intermediates (RNI) induced by bacterial lipopolysaccharide (LPS) in mice. The more effective compound, aminoguanidine (AG) inhibited the rise in RNI induced by P. chabaudi and increased mortality, but had no effect on parasitaemia. Inducers and donors of NO were screened for their ability to increase RNI and the most effective agents evaluated for their ability to modify P. berghei infection. S‐Nitrosoglutathione had little effect, but LPS decreased parasitaemia and mortality. An inconsistent relationship is evident between the abilities of these agents to modify NO activity and their effects on malaria in mice. Increased mortality in mice with P. chabaudi treated with AG indicates a reduction in resistance. The absence of an effect on parasitaemia by a NOS inhibitor or NO donor indicates either RNI have insignificant antimalarial action in vivo or the efficacy of the compounds is inadequade. Resistance to P. berghei in LPS‐treated mice demonstrates an antiparasitic effect, but this may be attributable to factors other than NO.
Kinetics of eosinophil and IgE‐mast cell changes following infection with Angiostrongylus costaricensis in Wistar rats
Authors: Serra M. F. , Barreto E. O. , Silva J. P. , Azevedo V. , Mota E. M. , Pelajo‐Machado M. , Lucena S. , Pires A. L. A. , Carvalho V. , Cordeiro R. S. B. , Lenzi H. L. , Silva P. M. R. , Martins M. A. 
Published: August 2003

SUMMARY Human abdominal angiostrongyliasis is a severe eosinophilic disease caused by Angiostrongylus costaricensis. Previous studies have demonstrated that wild rodents are critically involved as definitive hosts to this nematode in nature. In this study, we have evaluated the susceptibility of Wistar rats (Rattus norvegicus) to A. costaricensis infection. Kinetics of parasitological and pathological changes, including the number of adult worms recovered from mesenteric arteries, and of IgE, mast cell and eosinophil levels in several compartments have been assessed. The oral inoculation of third‐stage larvae (L3) into adult Wistar rats led to a marked accumulation of worms in the branches of the mesenteric arteries 25 and 50 days post‐inoculation. Intense bone marrow eosinophilia ranging from 7 to 50 days was accompanied by marked accumulation of eosinophils in the blood, peritoneal and bronchoalveolar spaces. Eosinophilic periarteritis, oedema and granuloma in the intestinal and lung tissues were also histologically evident. Total serum IgE and specific anti‐parasite IgE peaked at 25 days post‐infection, as measured by ELISA and by the passive cutaneous anaphylaxis test, respectively. At that time point, there was a drastic reduction in the number of intact mast cells in the peritoneal effluent. These findings indicate that Wistar rats are permissive to A. costaricensis infection. IgE‐mast cell activation and massive tissue eosinophil infiltration are marked features in the process and are likely to play a crucial role in the immune‐response evoked by this parasite.
Constitutive expression of nitrate reductase changes the regulation of nitrate and nitrite transporters in Chlamydomonas reinhardtii
Authors: Navarro María Teresa , Prieto Rafael , Fernández Emilio , Galván Aurora 
Published: August 2003

SummaryThe effect of constitutive expression of nitrate reductase (NR) on the regulation pattern of nitrite and nitrate transporters (NT) has been analysed in Chlamydomonas reinhardtii. Strain Tx11‐8, bearing the chimeric Nia1 gene for NR under the control of the cabll‐1 gene promoter, showed a constitutive NR which was inactive in ammonium‐grown cells. In contrast to the wild‐type, incubation of Tx11‐8 in ammonium media containing nitrate at micromolar concentrations resulted in reactivation of inactive NR and excretion of nitrite. In addition, negligible amounts of NT gene transcripts were induced by nitrate in this strain. However, NT transcripts from Tx11‐8 cells were induced in amounts similar to those in the wild‐type, by preventing constitutive NR expression from the cabll‐1 gene promoter in the dark. Strains lacking high‐affinity NT and nitrite reductase activity and having the chimeric Nia1 gene have been constructed by genetic crosses. All these strains were sensitive to chlorate in ammonium‐containing media and excreted nitrite when nitrate was present at millimolar concentrations. Spontaneous chlorate‐resistant mutants isolated from these strains lacked constitutive NR activity though they constitutively expressed NR mRNA. The data strongly suggest that nitrate plays an important post‐transcriptional regulatory role and that NR is involved in the regulation of the nitrate/ nitrite transport activities in C. reinhardtii.
The Arabidopsis XET‐related gene family: environmental and hormonal regulation of expression
Authors: Xu Wei , Campbell Paul , Vargheese Ajay K. , Braam Janet 
Published: August 2003

SummaryEnzymes that modify cell wall components most likely play critical roles in altering size, shape, and physical properties of plant cells. Regulation of such modifying activity is expected to be important during morphogenesis and in eliciting developmental and physiological alterations that arise in response to environmental conditions. Previous work has shown that the Arabidopsis TCH4 gene encodes a xyloglucan endotransglycosylase (XET) which acts on the major hemicellulose of the plant cell wall. The expression of TCH4 is dramatically upregulated in response to several environmental stimuli (including touch, wind, darkness, heat shock, and cold shock) as well as the growth‐enhancing hormones, auxin and brassinosteroids. This paper reports the presence of an extensive XET,related (XTR) gene family in Arabidopsis. In addition to TCH4, this family includes two previously identified genes, EXT and Meri‐5, and at least five additional genes. The cDNAs of the XTR family share between 46 and 79% sequence identity and the predicted XTR proteins share from 37 to 84% identity. All eight proteins include potential N‐terminal signal sequences and most have a conserved motif (DEIDFEFLG) that is also found in Bacillusβ‐glucanase and may be important for enzyme activity. The members of the XTR gene family are differentially sensitive to environmental and hormonal stimuli. Magnitude and kinetics of regulation are distinct for the different genes. Differential regulation of expression of this complex gene family suggests a recruitment of related, yet distinct, cell wall‐modifying enzymes that may control the properties of cell walls and tissues during development and in response to environmental cues.
Use of Ac as an insertional mutagen in Arabidopsis
Authors: Bhatt Anuj M. , Page Tania , Lawson Emily J.R. , Lister Clare , Dean Caroline 
Published: August 2003

SummaryA pilot‐scale transposon mutagenesis experiment using a modified autonomous Activator (Ac) element, AcΔNael, was carried out in Arabidopsis thaliana. Four different transformants carrying Ac elements in different and defined genomic locations were used to generate 1000 plants carrying approximately 500 independent germinal transposition events. These plants were then selfed and the 1000 families screened in tissue culture and soil for phenotypic mutants. Fifty different families segregated mutations in their progeny. Preliminary Southern blot analysis of 29 families which segregated mutant progeny, showed that 28 had a transposed Ac. Six of the families were further tested for linkage between the transposed Ac and the mutant phenotype, and instability of the putatively tagged locus. Two of the mutants were shown to be tagged as they were tightly linked to a transposed Ac, and somatic and germinal reversion was associated with loss of Ac. One other mutant locus was shown to be closely linked to a transposed Ac, and therefore was likely to be tagged. The remaining three mutations were not tagged as they were not linked to a transposed Ac. In two of the tagged mutants Ac had transposed to closely linked sites, while in a third mutant the co‐segregating Ac had transposed to a site which was not tightly linked to the donor T‐DNA. Multiple insertions into the DIF1 locus were found, due to the preferential transposition of Ac to a linked site.
Social learning in fishes: a review
Authors: Brown Culum , Laland Kevin N 
Published: August 2003

AbstractAnimals acquire skills and knowledge from other animals, and fish are no exception. There is now strong experimental evidence that many species of fish exhibit social learning and traditional behaviours. Here, we review the literature pertaining to social learning in fish, focusing on (i) antipredator behaviour, (ii) migration and orientation, (iii) foraging, (iv) mate choice and (v) eavesdropping.
Learned recognition of conspecifics by fishes
Authors: Griffiths Siân W 
Published: August 2003

AbstractThe study of partner‐choice decisions of individual fish is a good way in which insights into patterns of school structure or territorial assemblages can be gained. Most initial work has focused on the recognition abilities and association patterns of fish in situations where the potential for adaptive costs and benefits is great, such as in the contexts of foraging or antipredator behaviour. However, the benefits of condition‐independent recognition and kin recognition may also have profound effects on patterns of movement and dispersal. Information regarding group membership may be especially important in understanding the spatial position of fish in threatened stocks, and may therefore have implications for fisheries management policies. Future work may therefore benefit from an exploration of the ecological contexts in which learned recognition is important in natural streams and rivers.
Social organisation, shoal structure and information transfer
Authors: Hoare D J , Krause J 
Published: August 2003

AbstractRecent work suggests that the social structure of fish shoals is nonrandom with strong tendencies for self‐sorting by phenotype in individuals of several species. The frequency of shoal encounters is high in most freshwater species but lower in pelagic fishes where intershoal distances tend to be greater. Detailed knowledge of the encounter rates between shoals and the exchange rates of individuals between shoals during encounters makes it possible to predict the transmission of learned behaviours through a population.
Remodeling of Sinus Node Function After Catheter Ablation of Right Atrial Flutter
Authors: Daoud Emile G. , Weiss Raul , Augostini Ralph S. , Kalbfleisch Steven J. , Schroeder Jason , Polsinelli Georgia , Hummel John D. 
Published: August 2003

Sinus Node Remodeling.
Introduction: The purpose of this study was to investigate the effect of ablation of right atrial flutter upon sinus node function in humans. Methods and Results:This study enrolled 35 patients. Twenty‐four patients (16 men and 8 women; age 68 ± 11 years) were referred for ablation of persistent atrial flutter (duration 8 ± 11 months). After ablation, there was abnormal sinus node function defined as a corrected sinus node recovery time (CSNRT) > 550 msec. The control group consisted of 11 patients who were undergoing pacemaker implantation for sinus node disease but did not have a history of atrial dysrhythmias or ablation. Within 24 hours of ablation or pacemaker implantation, baseline maximal CSNRT was measured through a permanent pacemaker by AAI pacing at six cycle lengths: 600, 550, 500, 450, 400, and 350 msec. CSNRT then was measured in the same manner at 48 hours, 14 days, and 3 months after ablation/pacemaker implantation. P wave amplitude and duration, and percent atrial sensing also were assessed at the same intervals. For patients undergoing atrial flutter ablation, there was progressive temporal recovery of CSNRT (1,204 ± 671 msec at baseline vs 834 ± 380 msec at 3 months; P < 0.001) and a significant increase in the percent atrial sensing and P wave amplitude at 3 months compared with baseline (P < 0.001). In control subjects, there was no change in the CSNRT, percent atrial pacing, or P wave amplitude. Conclusion: After ablation of persistent atrial flutter, there is temporal recovery of CSNRT and increase in spontaneous atrial activity. These findings suggest that atrial flutter induces reversible changes in sinus node function.
Response of Pulmonary Vein Potentials to Premature Stimulation
Authors: TADA HIROSHI , ORAL HAKAN , OZAYDIN MEHMET , GREENSTEIN RADMIRA , PELOSI FRANK , KNIGHT BRADLEY P. , STRICKBERGER S. ADAM , MORADY FRED 
Published: August 2003

Pulmonary Vein Potentials.
Introduction: Pulmonary vein potentials reflect depolarization of muscle fascicles within the myocardial sleeves that surround the pulmonary veins. The response of pulmonary vein potentials to premature stimulation has not been described. Methods and Results: In 31 patients with paroxysmal atrial fibrillation referred for segmental isolation of the pulmonary veins, programmed stimulation with a single atrial extrastimulus was performed from the coronary sinus. Bipolar and unipolar electrograms were recorded with a decapolar Lasso catheter positioned sequentially within the left superior, left inferior, and right superior pulmonary veins, near the ostium. Premature stimulation often resulted in greater separation of the atrial and pulmonary vein potentials recorded within the pulmonary veins, fractionation of the pulmonary vein potentials, a change in the circumferential activation sequence of the pulmonary vein potentials, and dropout of pulmonary vein potentials. Conclusion: In response to premature stimulation, the muscle fascicles within the myocardial sleeves that surround the pulmonary veins display a greater degree of decremental conduction than do the myocardial fibers in the adjacent left atrium, and they display heterogeneity in conduction properties and refractoriness. Discrimination of pulmonary vein potentials from atrial electrograms is facilitated by premature stimulation.
Acute and Chronic Electrophysiologic Changes Surrounding Radiofrequency Lesions
Authors: WOOD MARK A. , FULLER ITHIEL A. 
Published: August 2003

Electrophysiologic Changes Surrounding RF Lesions.
Introduction: Arrhythmia recurrences may occur after acutely successful radiofrequency (RF) ablation, suggesting reversible electrophysiologic effects on myocardial tissue. The aim of this study was to examine the electrophysiologic changes occurring in myocardium surrounding acute and chronic RF lesions. Methods and Results: RF lesions (60°C for 30 sec) were produced on the epicardial left ventricular surface of 35 isolated perfused rabbit hearts. Microelectrode transmembrane action potential recordings were made at 0.25‐mm intervals along the epicardial (n = 20) or intramural (n = 6) aspects of the lesions for up to 3.5 mm from the lesion edge at baseline and after acute RF lesion formation. In nine hearts, chronic lesions were studied with epicardial recordings made 22 ± 13 days after RF lesion formation. In the acute hearts at 600‐msec paced cycle length, action potential duration at 50% repolarization (APD50) and 90% repolarization (APD90) were reduced by up to 41% and 19%, respectively, within 2.5 mm from the lesion edge (all P < 0.05). Maximal action potential amplitude (APDmax) was reduced by 16% at 0.25 mm from the lesion edge (P = 0.009) but dV/dt was not changed. Conduction time (CT) from the outermost recording site to the lesion edge (3.5‐mm distance) was reduced from 16 ± 3 msec at baseline to 13 ± 4 msec post ablation (P = 0.006). Qualitatively similar findings occurred at 200‐msec cycle lengths. There were no changes in APD, CT, APDmax, or dV/dt surrounding the chronic lesions at 22 ± 13 days after lesion formation. Conclusion: Acutely following RF energy delivery, APD, APDmax, and CT are reduced in the tissue surrounding the lesion. These electrophysiologic changes resolve within 22 ± 13 days of lesion formation.