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Biomedical subjects

David A Richards

Publications and source records attributed to David A Richards.

At least 19 recordsLinked to original sources
PubMed2008

Two-dimensional and three-dimensional transthoracic echocardiography in surgical planning for right atrial metastatic melanoma.

Melanoma is the most common form of cardiac metastases. Surgical excision has been shown to be an effective palliative measure. This requires detailed definition of cardiac anatomy in relation to the tumour. Two-dimensional (2D), three-dimensional (3D) transthoracic (TTE) and transoesophageal echocardiography (TEE), spiral computerised tomography (CT) and magnetic resonance imaging (MRI) have all been described in aiding surgical planning for excision of cardiac tumours. In this case report, 3D-TTE provided excellent anatomical definition for surgical planning of a large right atrial melanoma precluding the need for more invasive and expensive investigations.

Diagnosis, Differential↗
PubMed2007

Predicting stress in pre-registration midwifery students attending a university in Northern England.

OBJECTIVE: to determine which variables predict stress (psychological distress) in pre-registration midwifery students. DESIGN: a cross-sectional survey, using a range of self-report measures bound together in a 'questionnaire pack'. SETTING: the study reported here is taken from a wider investigation into stress among nursing and midwifery students, undertaken in the nursing and midwifery department of a large university in Northern England. PARTICIPANTS: 120 pre-registration midwifery students pursuing one of three diploma programmes: 'standard', 'enhanced' and 'short'. MEASUREMENTS: multivariate logistic regression was used as the analytical technique. The variables used in the analyses undertaken were all derived from formal and study-specific, self-report measures included in the questionnaire pack. 'Stress' (whether a participant was psychologically distressed or not) was obtained via the General Health Questionnaire. Potential predictors of stress were collected from two formal measures (the Student Nurse Stress Index and the Coping Inventory for Stressful Situations) and from questions in the questionnaire pack designed to elicit demographic data and data of specific interest to nurse and midwife educators. FINDINGS: 102 questionnaire packs (85%) were returned. The prevalence of stress among participants was over 40%. A series of logistic regression analyses resulted in five competing regression models. Through a systematic selection process, two of these models were chosen for discussion. These models suggested that the key predictors of psychological distress in the population studied were self-report of stress levels, the type of midwifery programme being pursued, the use of 'task-oriented' coping and, possibly, whether or not a student smokes cigarettes. KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: despite the prevalence rate of 40%, the prevalence of stress among midwifery students is generally no better or worse than that of other students or of qualified health-care professionals. Those involved in midwifery education need to know how to manage student stress effectively. This can be achieved by ensuring that personal teachers (continue to) play a key role in supporting students, especially when students self-report high levels of stress. Incorporating formal stress-management training into pre-registration midwifery programmes may also be useful. Sound knowledge of the issues associated with student stress during curriculum design, however, may ultimately prove to be the most effective way of managing student stress. In a discipline such as midwifery, these issues are as divergent as the politics of midwifery, the processes used in recruitment and selection, the role of women in society, and the nature, quality and quantity of the learning experiences and the assessment strategies used.

Adaptation, Psychological↗
PubMed2006

The prevalence of nursing staff stress on adult acute psychiatric in-patient wards. A systematic review.

BACKGROUND: Concerns about recent changes in acute in-patient mental health care environments have led to fears about staff stress and poor morale in acute in-patient mental health care staff. AIM: To review the prevalence of low staff morale, stress, burnout, job satisfaction and psychological well-being amongst staff working in in-patient psychiatric wards. METHOD: Systematic review. RESULTS: Of 34 mental health studies identified, 13 were specific to acute in-patient settings, and 21 were specific to other non-specified ward-based samples. Most studies did not find very high levels of staff burnout and poor morale but were mostly small, of poor quality and provided incomplete or non-standardised prevalence data. CONCLUSIONS: The prevalence of indicators of low morale on acute in-patient mental health wards has been poorly researched and remains unclear. Multi-site, prospective epidemiological studies using validated measures of stress together with personal and organizational variables influencing staff stress in acute in-patient wards are required.

Acute Disease↗
PubMed2005

Glutamate induces the rapid formation of spine head protrusions in hippocampal slice cultures.

Synaptic plasticity at neuronal connections has been well characterized functionally by using electrophysiological approaches, but the structural basis for this phenomenon remains controversial. We have studied the dynamic interactions between presynaptic and postsynaptic structures labeled with FM 4-64 and a membrane-targeted GFP, respectively, in hippocampal slices. Under conditions of reduced neuronal activity (1 muM tetrodotoxin), we observed extension of glutamate receptor-dependent processes from dendritic spines of CA1 pyramidal cells to presynaptic boutons. The formation of these spine head protrusions is blocked by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonists and by agents that reduce the release of glutamate from presynaptic terminals. Moreover, spine head protrusions form in response to exogenously applied glutamate, with clear directionality toward the glutamate electrode. Our results suggest that spontaneously released glutamate is sufficient to activate nearby spines, which can then lead to the growth of new postsynaptic processes connecting to a presynaptic site. Spines thus can compare their recent history with that of neighboring synapses and modify local connectivity accordingly.

Animals↗
PubMed2005

Two modes of exocytosis at hippocampal synapses revealed by rate of FM1-43 efflux from individual vesicles.

We have examined the kinetics by which FM1-43 escapes from individual synaptic vesicles during exocytosis at hippocampal boutons. Two populations of exocytic events were observed; small amplitude events that lose dye slowly, which made up more than half of all events, and faster, larger amplitude events with a fluorescence intensity equivalent to single stained synaptic vesicles. These populations of destaining events are distinct in both brightness and kinetics, suggesting that they result from two distinct modes of exocytosis. Small amplitude events show tightly clustered rate constants of dye release, whereas larger events have a more scattered distribution. Kinetic analysis of the association and dissociation of FM1-43 with membranes, in combination with a simple pore permeation model, indicates that the small, slowly destaining events may be mediated by a narrow approximately 1-nm fusion pore.

Animals↗
PubMed2005

Prediction of appropriate timing of palliative care for older adults with non-malignant life-threatening disease: a systematic review.

BACKGROUND: most people in contemporary western society die of the chronic diseases of old age. Whilst palliative care is appropriate for elderly patients with chronic, non-malignant disease, few of these patients access such care compared with cancer patients. Objective referral criteria based on accurate estimation of survival may facilitate more timely referral of non-cancer patients most appropriate for specialist palliative care. OBJECTIVE: to identify tools and predictor variables that might aid clinicians estimate survival and assess palliative status in non-cancer patients aged 65 years and older. METHODS: systematic review and quality assessment using criteria modified from the literature. RESULTS: 11 studies that evaluated prognoses in hospitalised and community-based older adults with non-malignant disease were identified. Key generic predictors of survival were increased dependency of activities of daily living, presence of comorbidities, poor nutritional status and weight loss, and abnormal vital signs and laboratory values. Disease-specific predictors of survival were identified for dementia, chronic obstructive pulmonary disorder and congestive heart failure. No study evaluated the relationship between survival and palliative status. CONCLUSION: prognostic models that attempt to estimate survival of < or = 6 months in non-cancer patients have generally poor discrimination, reflecting the unpredictable nature of most non-malignant disease. However, a number of generic and disease-specific predictor variables were identified that may help clinicians identify older, non-cancer patients with poor prognoses and palliative care needs. Simple, well-validated prognostic models that provide clinicians with objective measures of palliative status in non-cancer patients are needed. Additionally, research that evaluates the effect of general and specialist palliative care on psychosocial outcomes in non-cancer patients and their carers is needed.

Aged↗
PubMed2005

Nursing attitudes towards acute mental health care: development of a measurement tool.

AIM: This paper reports the development, piloting and validation of a tool to measure attitudes for use with nursing staff working in acute mental health care units. BACKGROUND: The quality of care provided for service users in acute mental health care has come under both scrutiny and severe criticism. The attitudes of staff working in these environments have been cited as a contributory factor in poor care. No measure of attitudes specific to acute mental health has been reported. METHODS: A 64-question measure was constructed and distributed to a sample of qualified and unqualified nurses drawn from seven mental health care units in the North of England. Exploratory factor analysis and a number of other statistical tests were performed to validate the questionnaire. RESULTS: Preliminary analysis reduced the original 64 questions to 37. Five components were retained, accounting for 42% of the variance, and the five rotated factors were identified. The resultant 'Attitudes Towards Acute Mental Health Scale' (ATAMHS) achieved good internal reliability, with a Cronbach's alpha of 0.72. CONCLUSION: The construction and validation of the ATAMHS measure will enable improved understanding of the attitudes of nursing staff working in acute mental health care settings to occur. This measure is available for use in a clinical area of nursing in which attitude change is of fundamental importance for future development of care.

Acute Disease↗
PubMed2005

Synaptotagmin VII is targeted to secretory organelles in PC12 cells, where it functions as a high-affinity calcium sensor.

Synaptotagmin (syt) I is thought to act as a Ca2+ sensor that regulates neuronal exocytosis. Fifteen additional isoforms of syt have been identified, but their functions are less well understood. Here, we used PC12 cells to test the idea that different isoforms of syt impart cells with distinct metal (i.e., Ca2+, Ba2+, and Sr2+) requirements for secretion. These cells express syt's I and IX (syt IX sometimes referred to as syt V), which have low apparent metal affinities, at much higher levels than syt VII, which we show has a relatively high apparent affinity for metals. We found that syt I and VII partially colocalize on large dense core vesicles and that upregulation of syt VII produces a concomitant increase in the divalent cation sensitivity of catecholamine release from PC12 cells. Furthermore, RNA interference-mediated knockdown of endogenous syt VII reduced the metal sensitivity of release. These data support the hypothesis that the complement of syt's expressed by a cell, in conjunction with their metal affinity, determines the divalent cation sensitivity of exocytosis.

Animals↗
PubMed2004

Wet periods in northeastern Brazil over the past 210 kyr linked to distant climate anomalies.

The tropics are the main source of the atmosphere's sensible and latent heat, and water vapour, and are therefore important for reconstructions of past climate. But long, accurately dated records of southern tropical palaeoclimate, which would allow the establishment of climatic connections to distant regions, have not been available. Here we present a 210,000-year (210-kyr) record of wet periods in tropical northeastern Brazil--a region that is currently semi-arid. The record is obtained from speleothems and travertine deposits that are accurately dated using the U/Th method. We find wet periods that are synchronous with periods of weak East Asian summer monsoons, cold periods in Greenland, Heinrich events in the North Atlantic and periods of decreased river runoff to the Cariaco basin. We infer that the wet periods may be explained with a southward displacement of the Intertropical Convergence Zone. This widespread synchroneity of climate anomalies suggests a relatively rapid global reorganization of the ocean-atmosphere system. We conclude that the wet periods probably affected rainforest distribution, as plant fossils show that forest expansion occurred during these intermittent wet intervals, and opened a forest corridor between the Amazonian and Atlantic rainforests.

Atmosphere↗
PubMed2004

NHS Direct versus general practice based triage for same day appointments in primary care: cluster randomised controlled trial.

OBJECTIVE: To assess the relative effects on consultation workload and costs of off-site triage by NHS Direct for patients requesting same day appointments compared with usual on-site nurse telephone triage in general practice. DESIGN: Cluster randomised controlled trial. SETTING: Three primary care sites in York, England. PARTICIPANTS: 4703 patients: 2452 with practice based triage, 2251 with NHS Direct triage. All consecutive patients making requests for same day appointments during study weeks were eligible for the trial. MAIN OUTCOME MEASURES: Type of consultation after request for same day appointment (telephone, appointment, or visit); time taken for consultation; service use during the month after same day contact; costs of same day, follow up, and emergency care. RESULTS: Patients in the NHS Direct group were less likely to have their call resolved by a nurse and were more likely to have an appointment with a general practitioner. Mean total time per patient in the NHS Direct group was 7.62 minutes longer than in the practice based group. Costs were greater in the NHS Direct group--2.88 pounds sterling (0.88 pounds sterling to 4.87 pounds sterling) per patient triaged--as a result of the difference between the groups in proportions of patients at each final point contact after triage. CONCLUSIONS: External management of requests for same day appointments by nurse telephone triage through NHS Direct is possible but comes at a higher cost than practice nurse delivered triage in primary care. If NHS Direct could achieve the same proportions of consultation types as practice based triage, costs would be comparable.

Adolescent↗
PubMed2004

Fusion pore dynamics are regulated by synaptotagmin*t-SNARE interactions.

Exocytosis involves the formation of a fusion pore that connects the lumen of secretory vesicles with the extracellular space. Exocytosis from neurons and neuroendocrine cells is tightly regulated by intracellular [Ca2+] and occurs rapidly, but the molecular events that mediate the opening and subsequent dilation of fusion pores remain to be determined. A putative Ca2+ sensor for release, synaptotagmin I (syt), binds directly to syntaxin and SNAP-25, which are components of a conserved membrane fusion complex. Here, we show that Ca2+-triggered syt*SNAP-25 interactions occur rapidly. The tandem C2 domains of syt cooperate to mediate binding to syntaxin/SNAP-25; lengthening the linker that connects C2A and C2B selectively disrupts this interaction. Expression of the linker mutants in PC12 cells results in graded reductions in the stability of fusion pores. Thus, the final step of Ca2+-triggered exocytosis is regulated, at least in part, by direct contacts between syt and SNAP-25/syntaxin.

Animals↗
PubMed2004

Quality monitoring of nurse telephone triage: pilot study.

BACKGROUND: Nurse telephone triage is a popular way of managing workload in primary care and has been shown to be as safe as general practitioner (GP)-delivered alternatives. No studies have tested a routine method of assessing the quality of decision-making by triage nurses in primary care. AIMS: The aim of this paper is to describe a study to evaluate accuracy and utility of audiotaping telephone consultations to assess the quality of decisions made by practice nurses triaging same day appointment requests in routine practice. METHOD: An observational study was carried out using external assessment by GPs and nurse practitioners of triage quality in 218 audiotaped nurse telephone triage consultations. RESULTS: There were high levels of agreement between triage nurses and assessors on identifying the presenting problem. However, there were only moderate levels of agreement between GPs and nurse assessors both on level of information sought (kappa = 0.434) and appropriateness of outcome (kappa = 0.614). Assessors rated information-gathering as poor in 19.3% of calls (95% confidence interval 14.6 to 25.0), and seven (3.2%) consultations were rated as potentially dangerous (95% confidence interval 1.6 to 6.5). A 1% sample of all consultations would have a probability of 0.48 of identifying unsafe consultations and 0.99 probability of identifying consultations with poor information-gathering. CONCLUSIONS: External assessment of triage quality may be of only moderate accuracy and reliability. Nonetheless, considerable information can be gleaned from assessing audiotapes to assess consultation quality. Even where nurses are generally highly skilled and competent, a 1% review of triage consultations would be sufficient to identify their information-gathering learning needs in relation to patients' presenting problems. Audio-taped consultations could be an important part of clinical governance strategies.

Adult↗
PubMed2004

Survey of the impact of nurse telephone triage on general practitioner activity.

BACKGROUND: Nurse management of minor illness is a common method of demand management in primary care. Delegation of minor illness management to nurses may result in a change in patients' presenting problems and the consequent consulting behaviours of general practitioners (GPs). AIMS: To assess the impact of nurse telephone triage in primary care on the consulting behaviours of GPs. DESIGN OF STUDY: Survey of patient records. SETTING: Three primary care practice sites in York. METHOD: During randomly selected weeks, 1 month before and 6 months after the implementation of nurse telephone triage, we measured the number of presenting problems per patient and the following four consulting behaviours of doctors: the number of consultations during the 4 weeks before and after the index consultation, the number of prescribed items, the number of outside referrals, and the number of investigations. RESULTS: During standard management 1102 index consultations were identified, and during triage 1080 were identified. Patients seen by doctors in the triage system had significantly more presenting problems and received more consultations, prescriptions, and investigations. Numbers of referrals to secondary care were not different. CONCLUSIONS: Delegating the management of patients with minor illness to nurses in a telephone triage system may result in an overall increase in the number of presenting problems per patient, as well as changing GPs' consulting behaviours. Appointment systems may have to be adjusted to ensure patients receive more GP time. Further work on developing measures of complexity and controlled studies of the impact of new working arrangements on workload in primary care are required.

Adult↗
PubMed2003

Synaptotagmins I and II mediate entry of botulinum neurotoxin B into cells.

Botulinum neurotoxins (BoNTs) cause botulism by entering neurons and cleaving proteins that mediate neurotransmitter release; disruption of exocytosis results in paralysis and death. The receptors for BoNTs are thought to be composed of both proteins and gangliosides; however, protein components that mediate toxin entry have not been identified. Using gain-of-function and loss-of-function approaches, we report here that the secretory vesicle proteins, synaptotagmins (syts) I and II, mediate the entry of BoNT/B (but not BoNT/A or E) into PC12 cells. Further, we demonstrate that BoNT/B entry into PC12 cells and rat diaphragm motor nerve terminals was activity dependent and can be blocked using fragments of syt II that contain the BoNT/B-binding domain. Finally, we show that syt II fragments, in conjunction with gangliosides, neutralized BoNT/B in intact mice. These findings establish that syts I and II can function as protein receptors for BoNT/B.

Amino Acid Sequence↗
PubMed2003

Synaptic vesicle pools at the frog neuromuscular junction.

We have characterized the morphological and functional properties of the readily releasable pool (RRP) and the reserve pool of synaptic vesicles in frog motor nerve terminals using fluorescence microscopy, electron microscopy, and electrophysiology. At rest, about 20% of vesicles reside in the RRP, which is depleted in about 10 s by high-frequency nerve stimulation (30 Hz); the RRP refills in about 1 min, and surprisingly, refilling occurs almost entirely by recycling, not mobilization from the reserve pool. The reserve pool is depleted during 30 Hz stimulation with a time constant of about 40 s, and it refills slowly (half-time about 8 min) as nascent vesicles bud from randomly distributed cisternae and surface membrane infoldings and enter vesicle clusters spaced at regular intervals along the terminal. Transmitter output during low-frequency stimulation (2-5 Hz) is maintained entirely by RRP recycling; few if any vesicles are mobilized from the reserve pool.

Animals↗
PubMed2003

Access and effectiveness in psychological therapies: self-help as a routine health technology.

The ability of psychological treatment services to deliver effective and accessible mental healthcare, as demanded by the National Service Framework for mental health, is compromised by the traditional configuration of psychological therapy services, powerful gatekeeping by these services and the difficulties which exist in engaging primary care in mental healthcare. Although a number of service models have been suggested, most address access from the perspective of secondary care service providers. In particular, self-help, a powerful ideology and a clinically effective health technology, is given insufficient prominence in psychological therapy services. Self-help is often only considered for mild problems or as an adjunct to therapy, and it is assumed that mental health professionals with traditional therapeutic skills are needed to support self-help. Following a review of access and self-help in psychological therapies, the present authors propose criteria against which services could be designed in order to fully utilise self-help as a powerful health technology in psychological therapies. Accompanying these criteria is a research framework drawn from recent work on access and illness self-management that can be used to evaluate the performance of services attempting to improve access to psychological therapies.

Adaptation, Psychological↗
PubMed2003

Improving access to primary mental health care: uncontrolled evaluation of a pilot self-help clinic.

Psychological therapy is widespread in primary care, but demand often exceeds supply. Innovative self-help approaches may overcome some problems associated with access to therapists. The feasibility, acceptability, efficiency, and effectiveness of a fast-access mental health self-help clinic were examined in a pilot study. The therapist saw 159 patients in 16 months, and on average required only one hour per patient. Generally, patients who used the clinic were satisfied. They reported similar levels of distress at baseline as patients in traditional psychological therapy services, and comparable outcomes. The self-help clinic approach should be evaluated formally within a randomised controlled trial.

Adolescent↗