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Biomedical subjects

R Baker

Publications and source records attributed to R Baker.

At least 73 records · Page 4Linked to original sources
PubMed2001

Reducing the variability of oxygen consumption measurements.

The oxygen consumption (O(2)) of 10 able-bodied adults each walking at a variety of cadences and hence speeds was measured. The effect on variability of subtracting the resting oxygen rate from gross measurements and of normalising walking speed to the subject's height was investigated. Both of these were indeed found to reduce variability. A total reduction of more than 40% in the variability of O(2) cost measurements was observed. Using these techniques it was found that, at walking speeds below the average, nett O(2) cost per height was very nearly independent of walking speed.

Adult↗
PubMed2001

In vivo intracellular recording and perturbation of persistent activity in a neural integrator.

To investigate the mechanisms of persistent neural activity, we obtained in vivo intracellular recordings from neurons in an oculomotor neural integrator of the goldfish during spontaneous saccades and fixations. Persistent changes in firing rate following saccades were associated with step changes in interspike membrane potential that were correlated with changes in eye position. Perturbation of persistent activity with brief intracellular current pulses designed to mimic saccadic input only induced transient changes of firing rate and membrane potential. When neurons were hyperpolarized below action potential threshold, position-correlated step changes in membrane potential remained. Membrane potential fluctuations were greater during more depolarized steps. These results suggest that sustained changes in firing rate are supported not by either membrane multistability or changes in pacemaker currents, but rather by persistent changes in the rate or amplitude of synaptic inputs.

Action Potentials↗
PubMed2001

Elevated acute-phase protein in stunted Nepali children reporting low morbidity: different rural and urban profiles.

This study examined the associations between severity of stunting, plasma protein concentrations and morbidity of 104 Nepali boys, aged 10-14 years, living in contrasting environments. Boys from a remote village were compared with three similarly aged urban groups: poor squatters, homeless street children, and middle-class schoolchildren. All but the middle-class group were stunted, particularly village boys whose mean height-for-age z-score (-2.97, SD 0.82) indicates severe growth retardation. Stunting was significantly associated with increased plasma levels of the acute-phase protein alpha1-antichymotrypsin itself inversely related to plasma levels of albumin. Plasma ACT levels of village children (mean 1.52 g/l, SD 0.43) were three to four times higher than those of squatters and homeless street children, and five times higher than those of middle-class boys. Despite being the most severely stunted and having the most abnormal plasma protein values, village children reported the lowest burden of disease, a contradiction which may reflect exposure to sub-clinical infections or habituation to illness and low expectation of treatment. This study draws attention to the strikingly high levels of ACT and of stunting in the rural sample, and cautions on the use of uncorroborated morbidity reports across different epidemiological and socio-ecological environments. Possible mechanisms to explain the impact of illness and inflammation on growth faltering are discussed.

Acute-Phase Proteins↗
PubMed2001

Features of primary health care teams associated with successful quality improvement of diabetes care: a qualitative study.

BACKGROUND: In quality improvement activities such as audit, some general practices succeed in improving care and some do not. With audit of care likely to be one of the major tools in clinical governance, it would be helpful to establish what features of primary health care teams are associated with successful audit in general practice. OBJECTIVE: The aim of the present study was to identify those features of primary health care teams that were associated with successful quality improvement during systematic audit of diabetes care. METHOD: Semi-structured tape-recorded interviews were carried out with lead GPs and practice nurses in 18 general practices in Leicestershire that had the opportunity to improve their care and had completed two data collections in a multipractice audit of diabetes care. The interviewees were asked to describe their practice's approach to audit and the transcripts were coded for common features and judged for strength of feeling by blinded independent raters. Features common to practices that had, and those that had not, managed to improve diabetes care were identified. RESULTS: Six features were identified reliably in the transcripts by blinded independent raters. Four were significantly associated with the successful improvement of care. Success was more likely in teams in which: the GP or nurse felt personally involved in the audit; they perceived their teamwork as good; they had recognized the need for systematic plans to address obstacles to quality improvement; and their teams had a positive attitude to continued monitoring of care. A positive attitude to audit and a personal interest in the disease were not associated with improvement in care. CONCLUSIONS: Success in improving diabetes care is associated with certain organizational features of primary health care teams. Experimental studies are required to determine whether the development of teamwork enables practice teams to identify and overcome systematically the obstacles to improved quality of patient care that face them.

Diabetes Mellitus↗
PubMed2001

Just plain uggly.

Explore the source record for details and available documents.

Disease Outbreaks↗
PubMed2001

Quantitative and qualitative assessment of women's experience of a one-stop menstrual clinic in comparison with traditional gynaecology clinics.

OBJECTIVE: A quantitative and qualitative evaluation of the views of patients attending two types of clinics for menstrual disorders. METHODS: Semi-structured qualitative interview and quantitative questionnaire. SETTING: Five traditional general gynaecology clinics and a one-stop menstrual clinic, where investigations are performed and results given to patients on the same day. PARTICIPANTS: Two hundred and thirty-nine women (126 from the gynaecology clinic and 113 from the menstrual clinic) were recruited into the quantitative study; 18 and 26 patients from the gynaecology and the menstrual clinic, respectively, were interviewed for the qualitative study. MAIN OUTCOME MEASURES: Women's views about their care and progress towards resolution of their problem. RESULTS: Following the initial consultation, 106 (84%) of the gynaecology clinic, and 98 (87%) of the menstrual clinic patients completed the first part of the questionnaire. Of those, 75 (71%) and 79 (81%) patients from the two types of clinic, respectively, completed a follow up questionnaire one year later. There were statistically significant differences in all the components of the first part of the questionnaire (information, continuity, waiting, organisation, and limbo) in favour of the one-stop menstrual clinic. After one year, there was a statistically significant difference in one of the components, patient centeredness, but not in overall process co-ordination. The interviews showed that patients attending the menstrual clinic appreciated getting the results of their investigations on the same day. They also found the organisation of the one-stop menstrual clinic more closely suited to their needs and as a result were more likely to feel they were making progress. CONCLUSION: Women were consistently more positive about their experience in the one-stop clinic. One-stop clinics organised to meet the needs of patients might be appropriate for other clinical conditions. The combination of quantitative and qualitative methods is an effective method of assessing patients' views of health services.

Adult↗
PubMed2001

Development of the vertebrate inner ear.

The inner ear, also called the membranous labyrinth, contains the cochlea, which is responsible for the sense of hearing, and the vestibular apparatus, which is necessary for the sense of balance and gravity. The inner ear arises in the embryo from placodes, which are epithelial thickenings of the cranial ectoderm symmetrically located on either side of hindbrain rhombomeres 5 and 6. Placode formation in mice is first visible at the 12-somite stage and is controlled by surrounding tissues, the paraxial mesoderm and neural ectoderm. Diffusible molecules such as growth factors play an important role in this process. The activity of several genes confers the identity to the placodal cells. Subsequent cellular proliferation processes under influences from the adjacent hindbrain cause the inner ear epithelium to invaginate and form a vesicle called the otocyst. Combinatorial expression of several genes and diffusible factors secreted from the vesicle epithelium and hindbrain control specification of distinct inner ear compartments. Transplantation studies and inner ear in vitro cultures show that each of these compartments is already committed to develop unique inner ear structures. Later developmental periods are principally characterized by intrinsic differentiation processes. In particular, sensory patches differentiate into fully functional sensory epithelia, and the semicircular canals along with the cochlear duct are elaborated and ossified.

Animals↗
PubMed2001

Development of guidelines to facilitate improved support of South Asian carers by primary health care teams.

BACKGROUND: Evidence based guidelines are regarded as an appropriate basis for providing effective health care, but few guidelines incorporate the views of users such as carers. AIM: To develop guidelines to assist primary health care teams (PHCTs) in their work with carers within South Asian communities. METHODS: The guidelines were drawn up by a development group consisting of members of teams in areas with South Asian communities (Leicester and Bradford). The teams were invited to make their recommendations based on a systematic review of literature on minority ethnic carers and the findings of a study of the needs and experiences of local South Asian carers. A grading system was devised to enable the teams and a group of expert peer reviewers to assess the quality of evidence in support of each recommendation. RESULTS: The teams agreed seven recommendations, graded according to available evidence and strength of opinion. External peer review supported the PHCTs' interpretation of evidence and their recommendations. The recommendations included consideration of communication and information for carers, coordination of care within teams, and recognition by team members of the roles of carers and their cultural and religious beliefs. CONCLUSION: There are particular steps that PHCTs can take to improve their support of South Asian carers. It is possible to develop guidelines that take users' views into account and incorporate evidence from qualitative studies.

Asia, Western↗
PubMed2001

Vestibuloocular reflex of the adult flatfish. III. A species-specific reciprocal pattern of excitation and inhibition.

In juvenile flatfish the vestibuloocular reflex (VOR) circuitry that underlies compensatory eye movements adapts to a 90 degrees relative displacement of vestibular and oculomotor reference frames during metamorphosis. VOR pathways are rearranged to allow horizontal canal-activated second-order vestibular neurons in adult flatfish to control extraocular motoneurons innervating vertical eye muscles. This study describes the anatomy and physiology of identified flatfish-specific excitatory and inhibitory vestibular pathways. In antidromically identified oculomotor and trochlear motoneurons, excitatory postsynaptic potentials (EPSPs) were elicited after electrical stimulation of the horizontal canal nerve expected to provide excitatory input. Electrotonic depolarizations (0.8-0.9 ms) preceded small amplitude (<0.5 mV) chemical EPSPs at 1.2-1.6 ms with much larger EPSPs (>1 mV) recorded around 2.5 ms. Stimulation of the opposite horizontal canal nerve produced inhibitory postsynaptic potentials (IPSPs) at a disynaptic latency of 1.6-1.8 ms that were depolarizing at membrane resting potentials around -60 mV. Injection of chloride ions increased IPSP amplitude, and current-clamp analysis showed the IPSP equilibrium potential to be near the membrane resting potential. Repeated electrical stimulation of either the excitatory or inhibitory horizontal canal vestibular nerve greatly increased the amplitude of the respective synaptic responses. These observations suggest that the large terminal arborizations of each VOR neuron imposes an electrotonic load requiring multiple action potentials to maximize synaptic efficacy. GABA antibodies labeled axons in the medial longitudinal fasciculus (MLF) some of which were hypothesized to originate from horizontal canal-activated inhibitory vestibular neurons. GABAergic terminal arborizations were distributed largely on the somata and proximal dendrites of oculomotor and trochlear motoneurons. These findings suggest that the species-specific horizontal canal inhibitory pathway exhibits similar electrophysiological and synaptic transmitter profiles as the anterior and posterior canal inhibitory projections to oculomotor and trochlear motoneurons. Electron microscopy showed axosomatic and axodendritic synaptic endings containing spheroidal synaptic vesicles to establish chemical excitatory synaptic contacts characterized by asymmetrical pre/postsynaptic membrane specializations as well as gap junctional contacts consistent with electrotonic coupling. Another type of axosomatic synaptic ending contained pleiomorphic synaptic vesicles forming chemical, presumed inhibitory, synaptic contacts on motoneurons that never included gap junctions. Altogether these data provide electrophysiological, immunohistochemical, and ultrastructural evidence for reciprocal excitatory/inhibitory organization of the novel vestibulooculomotor projections in adult flatfish. The appearance of unique second-order vestibular neurons linking the horizontal canal to vertical oculomotor neurons suggests that reciprocal excitation and inhibition are a fundamental, developmentally linked trait of compensatory eye movement circuits in vertebrates.

Abducens Nerve↗
PubMed2001

A randomized controlled trial of the effects of multi-sensory stimulation (MSS) for people with dementia.

OBJECTIVES: To investigate short-term effects of Multi-Sensory Stimulation (MSS) on behaviour, mood and cognition of older adults with dementia, the generalization of effects to day hospital and home environments and the endurance of any effects over time. DESIGN: A randomized controlled trial comparing MSS with a credible control of one-to-one activities. METHODS: Fifty patients with diagnoses of moderate to severe dementia were randomized to either MSS or Activity groups. Patients participated in eight 30-minute sessions over a 4-week period. Ratings of behaviour and mood were taken before, during and after sessions to investigate immediate effects. Pre, mid, post-trial, and follow-up assessments were taken to investigate any generalization of effects on cognition, behaviour at the day hospital and behaviour and mood at home and endurance of effects once sessions had ceased. RESULTS: Immediately after MSS and Activity sessions patients talked more spontaneously, related better to others, did more from their own initiative, were less bored/inactive, and were more happy, active or alert. Both groups were more attentive to their environment than before, with a significantly greater improvement from the MSS group. At the day hospital, patients in the Activity group improved on their 'speech skills' (amount of speech; initiation of speech), whereas the MSS group remained unchanged during the trial. The MSS group showed a significant improvement in mood and behaviour at home compared to the Activity group whose behaviour deteriorated. No longer-term benefits were shown; indeed, behaviour declined sharply during the month follow-up period. CONCLUSIONS: Both MSS and Activity sessions appear to be effective and appropriate therapies for people with dementia.

Acoustic Stimulation↗
PubMed2001

Continuity of care and trust in one's physician: evidence from primary care in the United States and the United Kingdom.

BACKGROUND AND OBJECTIVES: Patients' trust in their physician to act in their best interest contributes to the effectiveness of medical care and may be related to the structure of the health care system. This study explored the relationship between continuity of care and trust in one's physician, particularly in terms of differences between the United States and the United Kingdom (UK). METHODS: We conducted a cross-sectional survey of adult patients (n = 418 in the United States and n = 650 in the UK) who presented in outpatient primary care settings in the United States (Charleston, SC, and Lexington, Ky) and in the UK (Leicester and Exeter). RESULTS: A high percentage of both groups of patients reported having a usual place of care and doctor. A total of 69.8% of UK patients and 8.0% of US patients have had their regular physician for > or = 6 years. US patients (92.4%) are more likely than UK patients (70.8%) to value continuity with a doctor. Both groups had high levels of trust in their regular doctor. Trust was related to one continuity measure (length of time for the relationship) but not to another (usual provider continuity index more than 1 year). In a multivariate model, country of residence had no independent relationship with trust, but continuity of care was significantly related. CONCLUSIONS: Higher continuity is associated with a higher level of trust between a patient and a physician. Efforts to improve the relationship between patients and physicians may improve the quality and outcomes of care.

Adult↗
PubMed2001

Features of primary care associated with variations in process and outcome of care of people with diabetes.

BACKGROUND: There is now clear evidence that tight control of blood glucose and blood pressure significantly lowers the risk of complications in both type I and type II diabetes. Although there is evidence that primary care can be as effective as secondary care in delivering care for people with diabetes, standards in primary care are variable. Previous studies have shown that practice, patient or organisational factors may influence the level of care of patients with diabetes. However, these studies have been conducted in single geographical areas and involved only small numbers of practices. AIM: To determine the standard of diabetes care in general practice and to determine which features of practices are associated with delivering good quality care. DESIGN OF STUDY: A questionnaire survey and analysis of multi-practice audit data. SETTING: Three health authorities in England, comprising 169 general practices. METHOD: This study was conducted with a total population of 1,182,872 patients and 18,642 people with diabetes. Linkage analysis was carried out on data collected by a questionnaire, routinely collected health authority data, and multi-practice audit data collected by primary care audit groups. Practice annual compliance was measured with process and outcome measures of care, including the proportion of patients who had an examination of their fundi, feet, blood pressure, urine, glycated haemoglobin, and the proportion who had a normal glycated haemoglobin. RESULTS: Median compliance with process and outcome measures of care varied widely between practices: fundi were checked for 64.6% of patients (interquartile range [IQR] = 45.3-77.8%), urine was checked for 71.4% (IQR = 49.7-84.3%), feet were checked for 70.4% (IQR = 51.0-84.4%), blood pressure for 83.6% (IQR = 66.7-91.5%), and glycated haemoglobin was checked for 83.0% of patients (IQR = 69.4-92.0%). The glycated haemoglobin was normal in 42.9% of patients (IQR = 33.0-51.2%). In multiple regression analysis, compliance with measures of process of care were significantly associated with smaller practices, fundholding practices, and practices with a recall system. Practices with more socioeconomically deprived patients were associated with lower compliance with most process measures. Practices with a greater proportion of patients attending hospital clinics had lower compliance with process and outcome measures. Being a training practice, having a diabetes mini-clinic, having more nurses, personal care, and general practitioner or nurse interest in diabetes were not associated with compliance of process or outcome of care. CONCLUSIONS: Despite recent evidence that complications of diabetes may be delayed or prevented, this study has highlighted a number of deficiencies in the provision of diabetes care and variations in care between general practices. Provision of high quality diabetes care in the United Kingdom will present an organisational challenge to primary care groups and trusts, especially those in deprived areas.

Delivery of Health Care↗
PubMed2001

Diagnosis of heart failure in primary care: an assessment of international guidelines.

An appraisal of published, peer-reviewed guidelines, in terms of their development methodologies and clinical effectiveness, was undertaken using a published and validated appraisal tool. Electronic databases revealed 13 guidelines on heart failure but only seven of these referred to diagnosis. The quality of the published guidelines was variable but there was consensus over the main symptoms and diagnostic tests, although only two symptoms were mentioned in all guidelines. Only two guidelines scored greater than 50% for rigour of development.

Cardiovascular Diseases↗