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Biomedical subjects

M G Stewart

Publications and source records attributed to M G Stewart.

At least 37 records · Page 2Linked to original sources
PubMed2001

Practice patterns versus practice guidelines in pediatric otitis media.

OBJECTIVE: To study the practice patterns of physicians and their adherence to an evidence-based practice guideline (PG) on pediatric otitis media with effusion. We hypothesized that overall knowledge of the recommendations from the guidelines would be less than 75%, and that specialist physicians would have better knowledge of the recommendations than generalist physicians. METHODS: We performed a survey study of 1167 otolaryngologists, pediatricians, and pediatric otolaryngologists. Each physician was sent a 6-item survey asking about their practice patterns and treatment preferences for young children with otitis media with effusion. We compared responses between different specialties. RESULTS: The overall response rate was 48%. Only 8 (1.4%) of the 558 responding physicians answered all 6 items congruent with the PG. Overall, pediatricians, otolaryngologists, and pediatric otolaryngologists had similar total scores, but different scores on individual items. CONCLUSIONS: These results indicate that the practice patterns of pediatricians, otolaryngologists, and pediatric otolaryngologists differ from the recommendations of an evidence-based PG. In particular, 2 items covering key treatment recommendations were answered in agreement with the PG by fewer than half of the physicians. It is not clear from this study whether these discrepancies were due to poor dissemination or knowledge concerning the PG, or disagreement with its recommendations.

Child↗
PubMed2001

An incentive plan for professional fee collections at an indigent-care teaching hospital.

The authors describe the implementation and development of an incentive plan to improve professional fee collections at an indigent-care teaching hospital. They theorized that an incentive plan based on relative value unit (RVU) productivity would increase billings and collections of professional fees. Unique RVU targets were set for individual services based on the number of faculty full-time equivalents and average reported productivity for academic physicians by specialty. The incentive plan was based on the level of expected faculty billings, measured in RVUs, for each department. A "base + incentive" model was used, with the base budget being distributed monthly throughout the year, and the incentive held as a "withhold" to be paid at the year's end only if the billing target in RVUs was met. Additionally, a task force worked with physician billing office and the hospital to improve collections. In the first year after implementation of the system was in place, important increases were noted in total RVU productivity (30.5% over the previous year) and in collections (49.5% over the previous year). Sixteen of 23 departments exceeded their incentive targets, and it was possible to make distributions of professional fees to those departments, to be used within the hospital system to enhance clinical services. Moreover, the plan created an overall positive attitude toward billings and documentation of faculty activities. The authors believe that this kind of incentive plan will be increasingly important for academic faculty working in public hospital systems.

Efficiency↗
PubMed2001

Validation of a patient-graded instrument for facial nerve paralysis: the FaCE scale.

OBJECTIVE: To develop and validate a patient-based instrument to measure both facial impairment and disability, the Facial Clinimetric Evaluation (FaCE) Scale. STUDY DESIGN: Prospective instrument validation. METHODS: Eighty-six patients with a documented history of facial paralysis completed a preliminary, 51-item instrument (alpha FaCE Scale), as well as the previously developed Facial Disability Index (FDI) and the Medical Outcomes Study Short Form 36 Item Questionnaire (SF-36). Two weeks after completing these instruments, 76 patients again completed the alpha FaCE Scale. Forty-one of the patients were also evaluated using the House-Brackmann Grading System (HBGS) and the Facial Grading System (FGS). RESULTS: Exploratory principal component factor analysis grouped 15 FaCE Scale items into 6 impairment and disability categories (domains), forming the beta FaCE Scale. Overall, the test-retest reliability of the FaCE Scale was high (Spearman's correlation coefficient (r) = 0.88, P <.01), as were the reliability coefficients of the individual domains (r = 0.81-0.92, P <.01). The FaCE Scale domains showed appropriate correlation to global visual analogue scale questions posed on the original alpha FaCE Scale (r = 0.65-0.81, P <.01). Overall, the FaCE Scale showed significant correlation with HBGS and FGS scores (r = -0.55 and 0.57, respectively; P <.01). However, not all FaCE Scale domains correlated with the HBGS and FGS scores. CONCLUSIONS: A reliable and valid patient-based system to measure impairment and disability in facial paralysis has been developed. This system appears to be better than traditional, physician-graded scales for evaluating quality-of-life issues affected by facial disability.

Adolescent↗
PubMed2000

Quality of life and health status in pediatric tonsil and adenoid disease.

OBJECTIVE: To assess the baseline global health status and quality of life (QOL) in children with tonsil and adenoid disease. DESIGN: Cross-sectional multicenter survey series. SETTINGS: A tertiary academic pediatric specialty hospital and a tertiary academic hospital in 2 different cities. PATIENTS AND OTHER PARTICIPANTS: Consecutive series of 55 parents of children who were seen for tonsil and adenoid disease. INTERVENTION AND METHOD: Cross-sectional survey of the health status of affected children to assess their QOL and its relationship to tonsil and adenoid disease. MAIN OUTCOME MEASURES: Quality-of-life subscale scores of affected children on the Child Health Questionnaire version PF28 (CHQ-PF28); comparisons of population data from healthy normal children and children with asthma and juvenile rheumatoid arthritis. RESULTS: The overall health status and QOL of children with tonsil and adenoid disease is significantly worse than those of healthy normal children, as demonstrated by lower mean scores on several CHQ-PF28 subscales, including general health, physical functioning, behavior, bodily pain, and parental impact (emotional). In addition, the general health perception of children with tonsil and adenoid disease is similar to the perceptions of children with asthma and juvenile rheumatoid arthritis, but several aspects of health status, as measured by CHQ-PF28 subscale scores, were significantly worse in children with tonsil and adenoid disease. CONCLUSION: The health status impact of tonsil and adenoid disease appears to be quite significant, particularly in aspects related to the parental impact of the child's disease.

Child↗
PubMed2000

Unrecognized benign paroxysmal positional vertigo in elderly patients.

Balance disorders in elderly patients are associated with an increased risk of falls but are often difficult to diagnose because of comorbid chronic medical problems. We performed a cross-sectional study to determine the prevalence of unrecognized benign paroxysmal positional vertigo (BPPV) and associated lifestyle sequelae in a public, inner-city geriatric population. Dizziness was found in 61% of patients, whereas balance disorders were found in 77% of patients. Nine percent were found to have unrecognized BPPV. Multivariate analysis demonstrated that the presence of a spinning sensation and the absence of a lightheadedness sensation predicted the presence of unrecognized BPPV. Patients with unrecognized BPPV were more likely to have reduced activities of daily living scores, to have sustained a fall in the previous 3 months, and to have depression. These data indicate that unrecognized BPPV is common within the elderly population and has associated morbidity. Further prospective studies are warranted.

Accidental Falls↗
PubMed2000

Synaptic loss is accompanied by an increase in synaptic area in the dentate gyrus of aged human apolipoprotein E4 transgenic mice.

To investigate the relationship between the three isoforms of apolipoprotein E (E2, E3 and E4) and the integrity of the synaptic circuitry in the dentate gyrus of the hippocampus, we have estimated the synapse per neuron ratio and mean apposition zone area per synapse at the electron microscope level in the dentate gyrus of apolipoprotein E knockout and human apolipoprotein E transgenic mice aged six to 24months. During ageing, only in human apolipoprotein E4 mice was there a decrease in synapse per neuron ratio, accompanied by an increase in synaptic size. When these mice were compared with human apolipoprotein E2, apolipoprotein E knockout and wild-type mice at old age, they displayed the lowest synapse per neuron ratio, but similar apposition zone area. In contrast, as in our previous study, aged apolipoprotein E knockout mice did not show any sign of synaptic degeneration. The functional consequences of such morphological changes remain to be determined. However, if such age-related loss of synapses occurred in the brain of Alzheimer apolipoprotein E4 patients, they might be additive to pathological processes and could contribute to greater cognitive impairment.

Aging↗
PubMed2000

Re-structuring of synapses 24 hours after induction of long-term potentiation in the dentate gyrus of the rat hippocampus in vivo.

In male rats, long-term potentiation was induced unilaterally in the dentate gyrus, either by high frequency (200Hz) or theta rhythm stimulation. Structural synaptic changes were examined 24h after induction using quantitative electron microscopy. A disector technique was employed in order to estimate the density of synapses (using 70-80-nm sections) and of granule cell nuclei (using 2-microm sections) in the middle, and inner molecular layer in both hemispheres. Synaptic height and total lateral areas of synaptic active zones per unit tissue volume were assessed via assumption-free stereological techniques coupled with image analysis. The results obtained indicated that both synaptic density and number (corrected per neuron) of axo-spinous, but not axo-dendritic, synapses were approximately 40% higher in the middle, but not inner molecular layer of the potentiated hemisphere compared to the contralateral (control hemisphere). No significant inter-hemispheric difference was found in the volume densities of lateral areas of active zones. These data suggest that 24h after long-term potentiation induction, active zones of existing axo-spinous synapses either split forming separate contacts, or decrease in size while new synapses are formed.

Animals↗
PubMed2000

Age-dependent pre- and postsynaptic distribution of AMPA receptors at synapses in CA3 stratum radiatum of hippocampal slice cultures compared with intact brain.

Organotypic slice cultures of rat hippocampus are widely used as experimental preparations for the study of synaptic plasticity, but their degree of correspondence with intact brain is not fully known. Here, using postembedding immunogold labelling, we describe the ultrastructural distribution of AMPA-type glutamate receptors (GluR1-4) in CA3 stratum radiatum of organotypic hippocampal slice cultures at 10 days to 11 weeks in vitro and compare the labelling with intact brain of corresponding age. In both types of preparation, the 11-week-old samples contained the highest proportion of AMPA receptor-like immunoreactive synapses. The incidence of labelled synapses, however, was higher in vivo (49%) than in vitro (24%). The intensity of labelling (number of gold particles per labelled synapse) also increased with age and was also higher in vivo than in vitro. In both organotypic cultures and intact brain, labelling was frequently found at presynaptic sites, often attached to vesicular structures. The specificity of these findings was supported both by light microscopic immunolabelling of GluR2/3 subunits and by electron microscopic double labelling of different epitopes of the GluR2 subunit. The vesicular localization of AMPA receptors was supported by Western blot analysis of subcellular fractions. Morphological evidence of presynaptic excitatory innervation of glutamatergic neurons supports a functional role for presynaptically located AMPA receptors. Our results therefore suggest that AMPA receptors occur in both pre- and postsynaptic profiles and that the distribution of AMPA receptors in cultured brain slices is fundamentally similar to intact brain, but that synaptic maturation may be retarded in vitro.

Age Factors↗
PubMed2000

Does the severity of sinus computed tomography findings predict outcome in chronic sinusitis?

OBJECTIVES: We studied the association between the severity of pretreatment CT scan findings and the improvement in symptoms of chronic sinusitis after treatment. METHODS: We analyzed data from an ongoing prospective, nonrandomized clinical outcomes study of patients treated for chronic sinusitis at a tertiary-care academic medical center (n = 57, mean age 46.8 years). Disease-specific symptom severity was measured with a validated health status instrument, and CT stage was quantified with the Harvard CT staging system. RESULTS: In a multivariate analysis, symptom severity based on CT findings emerged as a strong predictor of both improvement in symptom score outcome (beta = 0.47, P = 0.01) and absolute symptom level after treatment (beta = -0.58, P = 0.001). CONCLUSIONS: Severity as assessed by a pretreatment CT scan is a strong predictor of outcome. Patients with higher symptom severity based on CT scans showed significantly larger improvement and lower absolute levels of symptom severity after treatment. This study links CT scan findings and subjective patient-based outcomes (symptom scores) using a validated outcomes instrument.

Chronic Disease↗
PubMed2000

Outcomes and quality of life in conductive hearing loss.

OBJECTIVE: The goal was to measure quality of life (QOL) and hearing-specific functional status before and after treatment of conductive hearing loss (CHL). STUDY DESIGN AND SETTING: A prospective, longitudinal, outcomes-based study was performed at an academic medical center. RESULTS: Mean baseline QOL scores in CHL patients were comparable with those of the general population. Audiometric studies indicated significant improvements in hearing threshold in all treated patients. There was no significant improvement in mean global QOL scores after treatment of CHL, although there was little room for improvement over baseline. The hearing-specific instrument did demonstrate significant improvements in emotional and social/situational hearing status after treatment. Patients treated with hearing aids had poorer baseline QOL and hearing status than patients treated with surgery and tended to show declines in QOL and only partial improvement in hearing-specific functional status after treatment. CONCLUSIONS: Treatment of CHL resulted in improvements in hearing-specific functional status, although changes were difficult to detect with a global QOL instrument.

Adolescent↗
PubMed2000

Quality of life and disease-specific functional status following microvascular reconstruction for advanced (T3 and T4) oropharyngeal cancers.

In an effort to evaluate quality-of-life benefits of ablative head and neck cancer surgery and microvascular reconstruction, a longitudinal study was undertaken in which patients with T3 or T4 oropharyngeal cancers without systemic metastases at presentation were administered both general and disease-specific quality-of-life instruments preoperatively and postoperatively. In an initial prospective pilot study, 17 cancer patients were evaluated both preoperatively and postoperatively using the Medical Outcomes Short-Form Health Survey questionnaire (SF-36) and the Performance Status Scale for Head and Neck Cancer Patients. In the second part of the study, the need was recognized for a different disease-specific measure, for more frequent intervals of longitudinal follow-up (rather than be limited by a single data collection point), and for a noncancer control group. Since then, 17 more cancer patients were evaluated in the second part of the study and were compared with patients who had similar reconstructions after suffering head and neck trauma and also with age-matched controls. Instead of the performance status scale, the University of Washington Head and Neck Quality of Life questionnaire was substituted. Interval assessments were done at 1, 3, 6, and 12 months and preoperatively. Whereas many of the general and disease-specific quality of life subclasses initially worsened following extensive surgery and radiation therapy, most returned to the preoperative baseline by 6 months following conclusion of treatment and surpassed pretreatment values at 1 year. It can be concluded, based on this study, that large resections and reconstructions for head and neck cancer patients are justified in terms of outcome; the resection controls the local disease, and the microvascular reconstruction restores quality of life and functional status.

Activities of Daily Living↗
PubMed2000

Acute temporal bone trauma: utility of high-resolution computed tomography.

OBJECTIVE: To determine the clinical utility of high-resolution computed tomography (HRCT) for temporal bone trauma evaluation and management. STUDY DESIGN: Retrospective review. SETTING: Level I trauma center. PATIENTS: Patients (n = 105) with evidence of temporal bone trauma. MAIN OUTCOME MEASURES: Statistically significant associations between HRCT, clinical, audiometric, and head CT findings, and management decisions; role of HRCT in management decisions. RESULTS: Statistical analysis demonstrated poor association between specific clinical and HRCT findings, and between HRCT findings and management decisions. The HRCT complemented decision making in 10% of cases and revealed asymptomatic carotid canal fractures in 9% of cases. CONCLUSION: Routine HRCT yields minimal clinical utility. Selective use of HRCT may complement decision making, but patient management is predominantly influenced by other factors. Although angiography was performed in cases of asymptomatic carotid canal fractures, no clinical utility for this practice was demonstrated. An algorithm for temporal bone trauma evaluation and management is presented.

Acute Disease↗
PubMed1999

GABA immunoreactivity in mouse barrel field after aversive and appetitive classical conditioning training involving facial vibrissae.

We have previously reported that a classical conditioning paradigm involving stimulation of a row of facial vibrissae produced an expansion of the cortical representation of the "trained row", labeled with 2-deoxyglucose (2DG), in layer IV of the barrel field. The present study has examined the pattern of GABA immunoreactivity (GABA-IR) in the cortical representation of row B of the facial vibrissae after (i) 3 days of aversive training, and (ii) 2 months of appetitive training, where stimulation of row B of vibrissae on one side of the snout was used as a conditioned stimulus. The most notable observation was a greater density of GABA-IR cells concentrated in the hollows of the "trained row" B barrels compared to the hollows in the barrel field of the opposite hemisphere in the same mouse. After aversive training, we noted a 2-fold increase in the density of GABA-IR neurons in the hollows of row B; after reward training, the increase amounted to 49%. In contrast, GABA-IR was unchanged in the control groups, which received only stimulation of vibrissae without the unconditioned stimulus. The classification of labeled neurons according to size revealed that the increase in density of GABA-IR neurons was confined to the small (12-15 microm) diameter group. We concluded that the GABAergic system undergoes up-regulation, after both associative learning paradigms, and that the population of small, GABAergic neurons plays an active role in use-dependent plasticity.

Animals↗
PubMed1999

Cellular correlates of stages of memory formation in the chick following passive avoidance training.

The process of memory formation has been investigated using the model of one-trial passive avoidance training in the one-day old domestic chick. We have unraveled a biochemically coherent cascade of processes which, beginning with transient ion and neurotransmitter flux, and by way of a sequence of interacting pre- and post-synaptic intracellular signalling steps, results in gene activation and the synthesis of cell adhesion molecules which appear to be the effective agents in the structural processes involved in remodelling of synaptic and neuronal circuits. Further, in a related series of experiments we have shown that these biochemical and morphological changes are accompanied by significant changes in the neurophysiological status of the neurons on the IMHV and LPO, in particular in terms of their engagement in bouts of high-frequency firing. However, much remains to be clarified, particularly the meaning of the time-dependent shifts in the location of the trace, and the ways in which these molecular and cellular events translate into changes in behavior in the animal.

Animals↗
PubMed1999

Hippocampal synapses: do they talk to their neighbours?

Recent experimental findings show that fast synaptic transmission can extend its actions beyond the immediate synaptic cleft. Whether this phenomenon results in significant crosstalk between typical neighbouring synapses remains unclear. This article considers two areas of the hippocampus, the CA1 and dentate gyrus, where important neural processing occurs. The results discussed do not provide a simple answer to the question of whether synapses can 'talk' to their neighbours, but they do reveal crucial physiological constraints that determine the significance of synaptic crosstalk, thus adding considerably to our understanding of chemical synaptic transmission.

Animals↗
PubMed1999

FENS 2000 - Federation of European Neuroscience Societies millennium meeting.

In two articles by Wolf Singer, published in TINS in 1994 and 1997, brief analyses were presented of the problems faced by the European neuroscience community in its attempt to provide a cohesive response to meet the challenge of the proclamation of the 'Decade of the Brain'. One of the most-important decisions was to promote a forum for European neuroscience that, among other activities, would hold bi-annual meetings, alternating with meetings of partner European neuroscience societies in the intervening year. The first fruit of this was the enormously successful meeting held in Berlin in June 1998. The next meeting, the FENS millennium meeting, will be held in Brighton, UK (24-28 June 2000).

Europe↗
PubMed1999

A quantitative autoradiographic comparison of binding to glutamate receptor sub-types in hippocampus and forebrain regions of a food-storing and a non-food-storing bird.

In two species of birds, food-storing marsh tits, P. palustris, and non-storing blue tits, P. caeruleus, quantitative receptor autoradiography was used to localize NMDA (N-methyl-D-aspartate)-sensitive [3H]glutamate, [3H]MK801, and [3H]AMPA binding sites, in six regions of the forebrain: hippocampus and parahippocampus, hyperstriatum accessorium (vision) and ventrale (sensory integration), neostriatum (auditory), and lobus parolfactorius (basal ganglia). In both species high levels of labelling to both NMDA and AMPA receptors were observed throughout the forebrain. However, a marked difference in receptor labelling was apparent between the two species, with levels of binding to NMDA ion channel sites being significantly lower (20%) in both the hippocampus and parahippocampus, in food storers compared to non-food storers. The levels of binding to other forebrain regions were remarkably similar in the two species. No differences were seen in the binding to AMPA receptors in forebrain regions of either species.

Animals↗