Biomedical subjects

M G Stewart

Publications and source records attributed to M G Stewart.

149 records · Page 9Linked to original sources

PubMedDate not supplied

The effects of a practice guideline on endoscopic sinus surgery at an academic center.

Practice guidelines (PG) (or clinical pathways) are increasingly important tools for standardizing health care delivery, improving efficiency, monitoring quality, and controlling costs. Health services researchers divide the delivery of health care into three stages: structure, process, and outcome. PGs are a technique to standardize the process of health care delivery, which may result in improved clinical outcomes or may maintain clinical outcomes while increasing process efficiency and decreasing costs. We describe the development and implementation of a PG for endoscopic sinus surgery at an academic center, and report preliminary results on the effects of the PG on the health care process. The PG was developed using a multidisciplinary combination of consensus-building and evidence-based techniques. Initially, participation in the PG was voluntary and at the attending physician's discretion. One year after implementation of the PG, 41 patients had been enrolled by members of the medical school's full-time faculty. Process and short-term outcome variables on those patients were compared to a random sample of 50 patients treated by the same physicians, but not using the PG. There was no evidence of selection bias into the PG based on demographics, severity of sinusitis, or the presence of comorbid factors. There were no differences in time spent in the operating room, postanesthesia care unit, or day surgery observation unit, between patients using the PG and not using the PG. However, patients not using the PG had a significantly higher rate of unplanned admission. Patients using the PG had significantly lower median hospital costs and charges than did patients not using the PG. In addition, median hospital costs and charges decreased steadily for all patients (not just those using the PG), simultaneous with the development and implementation of the PG. There were no differences in short-term clinical outcomes between PG and non-PG patients. In summary, the development and implementation of a PG for endoscopic sinus surgery resulted in lower hospital costs and charges while maintaining acceptable short-term clinical outcomes. PGs have important implications for improving the efficiency of the health care process.

Academic Medical Centers↗

PubMedDate not supplied

Prevalence of sinonasal symptoms in patients with HIV infection.

Infection with the human immunodeficiency virus (HIV) is increasing in prevalence, and disease patterns are changing as patient survival lengthens. The purpose of this cross-sectional epidemiological study was to assess the prevalence and severity of self-reported symptoms of otolaryngologic disease in a group of patients attending a general HIV outpatient clinic (n = 203), and to compare the prevalence of self-reported symptoms with a sample of patients without HIV infection (n = 100). Of the HIV-infected patients, 65% of patients had AIDS, 35% were HIV-positive, and the median CD4 count was 135. Although only 11% of patients had seen an otolaryngologist in the prior 6 months, the majority of patients (66%) reported the presence of sinonasal disease during that time. Allergic rhinitis (80%) and sinusitis (54%) were the most commonly reported sinonasal symptoms, and 44% regularly used nasal or sinus medications. Sinonasal disease severity was significantly higher than the self-reported severity of mouth/throat disease (p = 0.01), ear disease (p = 0.03), and neck/salivary disease (p = 0.01). Although patients' self-reported overall health status was associated (p = 0.02) with CD4 count, the severity of sinonasal symptoms was not associated (p = 0.93) with CD4 count. Similarly, sinonasal symptom severity did not differ between HIV-positive and AIDS patients (p = 0.45). In other words, sinonasal disease severity did not improve as general health status improved.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Severity staging in chronic sinusitis: are CT scan findings related to patient symptoms?

Chronic sinusitis is a prevalent problem. The symptoms of CS cause patients to seek medical attention, and therefore the presence of symptoms drives the use of health care resources. There is widespread clinical belief that computed tomography (CT) scan findings may be a reasonable proxy for disease severity in chronic sinusitis, and many authors have proposed that CT scan findings make up the key component in severity staging systems for chronic sinusitis. However, the relationship between symptom severity and CT scan findings in chronic sinusitis has not been well explained to date. To explore this relationship further, we examined data from consecutive patients with both a CT scan and a sinusitis symptom score, from ongoing prospective outcomes studies at two large academic centers in different cities (n = 254). CT scans were graded using two validated staging systems; symptom severity was assessed using two validated health status instruments and summary items. In addition, we explored multiple statistical modifications and permutations of CT staging to identify potential relationships between the two variables. In summary, no association between CT scan findings and symptom severity could be identified using both CT staging systems and patient-based symptom instruments. For instance, CT scans were examined: after eliminating normal scans, using different scoring algorithms, by worst side, by nonlinear association, when grouped into strata, and by eliminating patients with very severe disease; no statistical association was found between CT findings and patient-based symptoms using any of those techniques. Since symptom severity is a pivotal outcome measure in chronic sinusitis, these findings have significant implications for outcomes research and the development of severity staging systems.

Adolescent↗

PubMedDate not supplied

[Three-dimentional organization of synapses and astroglia in the hippocampus of rats and ground squirrels: new structural and functional paradigms of the synapse function].

The literature data and our own data on the synaptic plasticity and remodeling of synaptic organelles in the central nervous system are reviewed. Modern techniques of laser scanning confocal microscopy and serial thin sectioning for in vivo and in vitro studies of dendritic spines, including the relationship between morphological changes and the efficacy of synaptic transmission, are discussed using, in particular, a model of long-term potentiation. The organization of dendritic spines and postsynaptic densities of different categories as well as the role of filopodia in spine genesis were analyzed. It was shown that the method of serial ultrathin sections is the most effective for unbiased quantitative stereological analysis and 3D reconstructions. By using the refined method of serial ultrathin sections with subsequent three-dimensional reconstructions, the presence of giant mitochondria in hippocampal neuronal dendrites was demonstrated. It was shown that smooth endoplasmic reticulum forms a unified continuum with the outer membrane of the mitochondrial envelope within dendrites. It was suggested that this continuum provides calcium tunneling, which makes possible intracellular signal transduction during synaptic transmission. Evidence is presented indicating the presence of gap junctions ("electrical synapses") in the synapses of mammalian brain, as well as between glial processes, and between glial cells and neurons. Our data and the data of other authors show that glial cell processes form a structural and functional glial network, which modulates the functioning of the neuronal network. The connection of dendritic spines with the glial network is shown on 3D reconstructions by analyzing the neuropil volume in CA1 hippocampal area of ground squirrels in three functional states: normothermia, provoked arousal, and hibernation when brain temperature falls below 6 degrees C. The own data of the authors are discussed indicating the formation of more than five presynaptic boutons (multiple synapses) on both CA1 mushroom-like dendritic spines and CA3 thorny excrescences. On the basis of the analysis, new ideas of the organization and functioning of synapses were suggested.

Animals↗

PubMedDate not supplied

[Three-dimensional reconstruction of synapse and dendritic spines in the hippocampus of rats and ground squirrels: new paradigms of the structure and function of a synapse].

The article reviews the literature data and results obtained by the authors concerning synaptic plasticity and remodeling of synaptic organelles in the central nervous system. Modern techniques of laser scanning confocal microscopy and serial thin sectioning for in vivo and in vitro studies of dendritic spines including a correlation between morphological changes and synaptic transmission efficiency are discussed, particularly, in relation to long-term potentiation. Organization of different types of dendritic spines and involvement of filopodia in spine genesis are examined. Significance of serial ultrathin sections for unbiased quantitative stereological analysis and three-dimensional reconstructions is discussed. The contact of one dendritic spine with two presynaptic boutons (multiple synapses) on both CA1 mushroom dendritic spines is discussed. The analyzed findings suggest new ideas for organization and functioning of synapses.

Animals↗