Biomedical subjects

D Tolson

Publications and source records attributed to D Tolson.

At least 19 recordsLinked to original sources

PubMed2001

Exploring Spanish emergency nurses' lived experience of the care provided for suddenly bereaved families.

AIM OF THE STUDY: To investigate the experience of emergency nurses caring for suddenly bereaved family members in the clinical setting, particularly after they are informed about the loss of a loved one. DESIGN/METHODS: Data was obtained from semi-structured interviews with seven emergency nurses drawn from emergency nursing staff working in a Spanish Hospital. Interviews were tape recorded, and hermeneutic-phenomenological analysis was applied to gain understanding from the emergency nurses' experiences. SETTING: The Accident and Emergency department in the Hospital Universitario Insular de Gran Canaria (Spain). Study undertaken in partial fulfillment of the main author's MSc (Department of Nursing and Community Health) at Glasgow Caledonian University. RESULTS: Several themes emerged from those interviews, which appeared to form the basis of the emergency nurses' reality: knowing, relationships, culture and reality. They showed the need to reflect on personal and professional experiences to facilitate personal growth, discover meaning for emergency nurses and examine the possible implications for clinical care. CONCLUSIONS: This study enabled both participants and the researcher to evaluate critically what was troublesome from their perspective and to identify sources of innovation and liberation within everyday practices.

Adaptation, Psychological↗

PubMed2000

Early indication of effects of puromycin aminonucleoside using a fluorimetric assay of 2-aminoacridone-derivatized carbohydrates in urine.

This paper describes a novel noninvasive method to study the changes in free carbohydrates excreted in urine as a result of toxicity in the rat induced by the administration of puromycin aminonucleoside (PAN). Urine samples were collected for 24 h prior to dosing and at 8, 24, and 32 h postdosing. For each sample, free carbohydrates were extracted from the urine using a graphitized carbon column and then labeled with 2-aminoacridone (2-AMAC) prior to analysis by hydrophilic interaction liquid chromatography (HILC). Dramatic changes were seen in the profile of the carbohydrates at the 8- and 24-h time points. These changes in carbohydrate profiles may be useful as early indicators of toxicity.

Aminoacridines↗

PubMed2000

A probe for the versatile analysis and characterization of N-linked oligosaccharides.

A novel fluorescent probe, 3-(acetylamino)-6-aminoacridine (AA-Ac), has been synthesized and its applicability to the analysis of picomole levels of N-linked glycans investigated. AA-Ac was found to be an excellent derivatization reagent for N-linked glycans, giving at least twice the intensity of fluorescence as its predecessor 2-aminoacridone. AA-Ac-labeled glycans were analyzed by both normal and reversed-phase HPLC. They were also amenable to enzymatic sequencing and analysis by MALDI-TOF mass spectrometry, free zone capillary electrophoresis, and capillary electrophoresis/electrospray ionization mass spectrometry.

Carbohydrate Sequence↗

PubMed2000

Analysis of process impurities in the basic drug SB-253149 using capillary electrophoresis and on-line mass spectrometric detection.

Capillary electrophoresis with on-line electrospray ionisation mass spectrometry (CE/ESI-MS) has been used to identify process impurities in a batch of the anti-atherosclerotic drug, SB-253149. The impurities were separated from the main drug compound by capillary electrophoresis (CE) using an ammonium formate buffer at low pH in an untreated fused silica capillary. The CE method was initially developed using UV as the detection mode and then later structural elucidation work was achieved using an ion trap mass spectrometer. To maintain peak resolution and peak shape when the CE system was coupled to the mass spectrometer, a modified capillary cassette linked to a coaxial sheath flow electrospray ionisation (ESI) interface was used. By performing MS/MS experiments in conjunction with chemical knowledge of the reactivities of SB-253149, it was possible to propose molecular structures for impurities detected in the batch of SB-253149. The results from this study revealed that most of the process impurities in SB-253149 were dimeric derivatives of the parent molecule as well as trace levels of the starting material. This type of information was vital in process control and optimisation for the synthetic route for this drug.

Anticholesteremic Agents↗

PubMed2000

The analysis of basic and acidic compounds using non-aqueous CE and non-aqueous CE-MS.

It has been shown that non-aqueous capillary electrophoresis (NACE) can provide improved separations in comparison to those obtained using conventional CE under aqueous conditions (ACE). Previous work carried out in our laboratories involving initial investigations into the technique have been reported. Based on the findings of that work it was possible to separate a variety of basic pharmaceuticals from selected impurities and to obtain the successful separation of some hydrophobic sulphonic acids. The successful coupling of NACE to mass spectrometry (NACE-MS) has also been demonstrated.

Antidepressive Agents, Tricyclic↗

PubMed1999

A detailed analysis of neutral and acidic carbohydrates in human milk.

Reverse- and normal-phase chromatography have been used to separate a number of standard human milk oligosaccharides derivatized via a reductive amination reaction with 2-aminoacridone (2-AMAC). Analytes were detected by spectrofluorimetry and injected simultaneously with a hydrolyzed dextran ladder derivatized with methyl-4-aminobenzoate. The latter probe does not fluoresce at the wavelength of emission by the 2-AMAC derivatives, and the derivatized, hydrolyzed dextran components were visualized by their ultraviolet absorbance. This procedure gave precise measurements of the "size" of 2-AMAC oligosaccharides in terms of their glucose equivalent values. Analytical amounts of 2-AMAC oligosaccharide standards were also isolated for further characterization by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and electrospray ionization (ESI) mass spectrometry. MS-MS was also used to provide information on oligosaccharide sequences. This methodology was used successfully to characterize mixtures of neutral and acidic oligosaccharides from samples of human milk. This approach could be usefully applied to the study of glycoforms from a variety of samples such as those released from glycoproteins/glycolipids; these have been reported to be altered in a number of diseases, for example, cancer, cystic fibrosis, and autoimmune disease such as rheumatoid arthritis.

Aminoacridines↗

PubMed1999

Profiling of 2-aminoacridone derivatised glycans by electrospray ionization mass spectrometry.

Three different types of N-glycans, high-mannose, complex and hybrid, have been derivatised with 2-aminoacridone and analysed by electrospray mass spectrometry and tandem mass spectrometry (MS/MS) using a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer, fitted with a nanoflow electrospray ion source. Relatively simple MS/MS fragmentation patterns have been observed for each type of glycan, allowing rapid elucidation of the order in which the monosaccharide residues making up these glycans are linked to one another.

Aminoacridines↗

PubMed1999

Practice innovation: a methodological maze.

Practice innovation is an inevitable feature of a health culture preoccupied with evidence-based practice. The cyclical process of defining best practice, implementing and evaluating change represents an unparalleled opportunity for nurse researchers to engage in, and develop, practice through 'realistic evaluation'. However, the methodological dilemmas and challenges inherent in evaluation research which informs policy should not be under-estimated. This paper seeks to introduce and wrestle with some of the political tensions and methodological issues surrounding practice innovation when it is undertaken within an evaluative research framework. A critical pathway is presented to stimulate discussion and guide novice evaluators through this often perplexing methodological maze. A case study in audiological rehabilitation in elder care is used to illustrate the issues raised.

Aged↗

PubMed1999

An investigation of the components of best nursing practice in the care of acutely ill hospitalized older patients with coincidental dementia: a multi-method design.

The main aim of this study was to examine, from the consumer's perspective, the components of best nursing practice in the care of acutely ill hospitalized elderly people who coincidentally suffered from dementia. Due to the complexity of the problem under investigation a triangulated design was formulated. This design comprised survey methodology, audit and critical incident technique. Data derived from each of these approaches were analysed first in isolation and subsequently combined at a conceptual level. The sample comprised 213 people aged 65 years and older, who were consecutive admissions from two acute medical and two acute care of elderly people wards. Sixty-six per cent of these individuals were found to suffer from cognitive impairment, 40% experiencing severe problems. The documentary survey revealed that patients with normal or severely abnormal cognitive functioning were more likely to have this noted than those with mild-moderate levels of impairment. No evidence of formal assessment was located and only 15% of these patients had items included in their nursing care plans associated with their chronic confusion. A sub-sample of 41 chronically confused people and their main hospital visitor were invited to participate in critical incident interviews. These conversations led to the identification of four major themes which reflected the most valued aspects of the nursing care which had been received or observed. The relationship between documentary care scores and the proportion of positive descriptions of care within each of the four themes was explored. The findings indicate that acute nursing care is deemed only to be at its best when it is delivered in tandem with dementia care. Discrete areas for practice development are identified and standards to guide nursing care are proposed. In addition to the practice development issues raised by the work, the methodological lessons further advance the practice of multi-method research.

Acute Disease↗

PubMed1998

Two-dimensional chromatography in the analysis of complex glycans from transferrin.

Oligosaccharides released from human transferrin have been derivatized with 2-aminoacridone (2-AMAC) prior to analysis by either reversed- or normal-phase high-performance liquid chromatography. These separation methods are complementary and allow distinction between isomeric mono- and disialylated oligosaccharides, which terminate with Sia alpha 2-6Gal or Sia alpha 2-3Gal at the nonreducing end. Collected fractions of 2-AMAC-derivatized glycans were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, before and after desialylation.

Aminoacridines↗

PubMed1998

Direct structural analysis of 2-aminoacridone derivatized oligosaccharides by high-performance liquid chromatography/mass spectrometric detection.

In this preliminary study linear and branched oligosaccharides, derivatized with 2-aminoacridone, have been separated by reverse-phase high-performance liquid chromatography, and detected by positive-ion electrospray mass spectrometry. Tandem Mass spectra of the protonated carbohydrate analytes gave simple fragmentation patterns from which sequence information could be readily obtained.

Aminoacridines↗

PubMed1998

Nucleotide and amino acid sequences of the metallo-beta-lactamase, ImiS, from Aeromonas veronii bv. sobria.

The Aeromonas veronii bv. sobria metallo-beta-lactamase gene, imiS, was cloned. The imiS open reading frame extends for 762 bp and encodes a protein of 254 amino acids with a secreted modified protein of 227 amino acids and a predicted pI of 8.1. To confirm the predicted sequence, purified ImiS was digested and the resulting peptides were identified, yielding an identical sequence for ImiS, with 98% identity to CphA. Both possessed the putative active-site sequence Asn-Tyr-His-Thr-Asp at positions 88 to 92, which is unique to the Aeromonas metallo-beta-lactamases.

Aeromonas↗

PubMed1997

Listening in the care environment--chaos or clarity for the hearing-impaired elderly person.

The reported study evaluates listening circumstances within long-stay wards in an attempt to understand the nature of the environment and so develop and subsequently evaluate a programme of nursing intervention for hearing-impaired residents. Evidence is presented which indicates that improvement of the residents' listening environment, promotes adaptation to hearing aids and enhances residents' quality of life. It is recommended that attending to the listening environment becomes a concern of nurses working within continuing care facilities for elderly people.

Aged↗

PubMed1997

Age-related hearing loss in the dependent elderly population: a model for nursing care.

Advancing nursing care through the implementation of evidence-based practice is a legitimate professional ideal. In reality there are many complex issues that need be addressed before such a goal can be achieved. This paper takes an intermediate step towards the realization of this aim in one aspect of continuing care nursing through the presentation of a procedural model. The presented model is designed to stimulate debate as to what could be, and arguably should be the role of the nurse in relation to meeting the auditory rehabilitative needs of dependent elderly patients. The model is based upon a published management model which outlines the auditory rehabilitative process within a psychosocial framework. The original model has been modified as a result of knowledge synthesis from a range of specialist disciplines including nursing. The Audiological Care Model for Nursing is intended to offer an accessible guide to this often neglected aspect of care.

Activities of Daily Living↗

PubMed1997

Age-related hearing loss: a case for nursing intervention.

This review paper selectively examines the problem of age-related hearing loss. Drawing on specialist audiological research, nursing research and patient anecdotes to make a case for nursing intervention. The limitations of national prevalence estimates are highlighted with regard to dependent elderly people, and are challenged as political underestimations of need. Despite the evidence of an exceptionally high level of potential demand only a minority of elderly people who might benefit from amplification possess a hearing aid. Factors to explain the low levels of hearing aid ownership and use are discussed. Through considerable reference to the author's own research the potential for nurses to lead practice developments and initiate service reform in the management of age-related hearing loss is debated.

Aged↗

PubMed1996

Phosphonamidate analogues of dipeptides with carboxypeptidase A and beta-lactamase-inhibitory activity: elucidation of the mechanism of beta-lactamase inhibition by electrospray mass spectrometry.

A series of phosphonamidate compounds with different P1' amino acid residues have been shown to be irreversible inactivators of the serine beta-lactamase from Enterobacter cloacae P99. The efficiency of inhibition (based on k2/K values) of P99 by these derivatives, ordered in decreasing potency, is: beta-phenyl-beta-Ala > L-Phe > beta-Ala > Gly > D-Phe > D-Pro > D-thiazolidine. The D- and L-Phe compounds also inhibit carboxypeptidase A. The proline and thiazolidine derivatives were phosphonamidate methyl esters, whereas the others were salts of diacids. Electrospray mass spectrometry showed that equimolar mixtures of the P99 enzyme with each of the following derivatives, Gly, D-Phe, L-Phe, beta-Ala and beta-phenyl-beta-Ala, effected efficient adduct formation (70-95% of enzyme modified), illustrating the particularly active nature of some of these compounds. All the primary amino acid derivatives gave a similar mass increment, which suggests the displacement of the variable P1' part of the molecule. This observation provides evidence that the compounds phosphonylate the active-site serine, with the phosphonamidate bond as the scissile bond and the amino acid as the leaving group. The thiazolidine derivative (phosphonamidate methyl ester) also appeared to work by the same mechanism. The comparable proline derivatives caused lower than expected mass shifts of 227-229, and therefore it is proposed that with these compounds both the amino acid and the phosphonamidate ester methoxy group were displaced at the phosphorus atom during the inhibition process. Therefore, electrospray mass spectrometry has provided both a measure of potency and a rationale for the mechanism of inhibition of P99 by these compounds.

Carboxypeptidases↗

PubMed1996

The Roy Adaptation Model: a consideration of its properties as a conceptual framework for an intervention study.

The underlying premise of this paper is the belief that one of the core values of nursing research is its ability to demonstrate that nursing interventions influence care outcomes. From this perspective the contribution offered by the Roy Adaptation Model for Nursing within an intervention study is evaluated. Although it was believed that the model enriched the study in several ways, its overall contribution was likened to a "conceptual stepping stone', used by the researcher en route back towards its underlying theories and classical intervention design methodologies.

Adaptation, Psychological↗

PubMed1995

Dissociation between tissue iron concentrations and transferrin saturation among inbred mouse strains.

Excessive absorption of dietary iron results in pathologic hepatic iron accumulation in the genetic disorder hemochromatosis. Genetic factors have also been suggested to play a role in African iron overload that is induced by the intake of iron-rich fermented beer. We have used inbred strains of mice to investigate previously unrecognized genetic factors controlling iron metabolism. Among different strains of mice fed a basal iron diet, serum iron levels varied twofold. In contrast, serum transferrin levels were remarkably constant. This indicates that transferrin saturation with iron, but not the serum level of transferrin, is likely to be genetically determined in mice. Hepatic iron stores also varied twofold among the different mouse strains. Remarkably, hepatic iron stores failed to reflect transferrin saturation, suggesting that different genetic factors control transferrin saturation and hepatic iron stores. When mice were challenged with a high-iron diet, the concentration of carbonyl iron required to completely saturate transferrin with iron was 10 times greater for C57BL/6 and BALB/c mice than for DBA/2 and AKR mice. These results are reminiscent of the iron-loading locus proposed to interact with dietary iron in African iron overload. Our studies with inbred strains of mice have revealed a number of novel control points in iron metabolism that may be genetically determined. The mouse model may thus be useful for understanding the molecular basis of hemochromatosis and African iron overload.

Animals↗