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Biomedical subjects

C O'Connor

Publications and source records attributed to C O'Connor.

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

Influenza outbreak in a correctional facility.

The outbreak of influenza in a corrections facility occurred during August 2000. The outbreak progressed following introduction of the disease by a member of the public to the facility. Rapid diagnosis and typing of the influenza isolates was available, although two prisoners required hospital admission due to the severity of complications at the time of diagnosis. The group demonstrated rapid transmission of the virus by the respiratory route and probably by fomites. The identified infecting virus was A/Moscow-like, an H3N2 subtype typically associated with large outbreaks. Prevention of such outbreaks will involve either achieving high rates of vaccination within the risk groups, or rapid (possibly point of care) diagnosis with the institution of antiviral therapy within 48 hours of symptoms. Influenza control within institutions is feasible using such strategies, although it requires considerable planning to have such approaches in place during winter--a time when institutional staff absenteeism is typically high.

Disease Outbreaks↗
PubMed2000

Gender differences in the polysomnographic features of obstructive sleep apnea.

We examined the influence of gender on the polysomnographic features of obstructive sleep apnea (OSA) in a retrospective study of 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity of OSA was determined from the apnea- hypopnea index (AHI) for total sleep time (AHI(TST)), and was classified as mild (5 to 25 events/h), moderate (26 to 50 events/h), and severe (> 50/events/h). Differences in OSA during different stages of sleep were assessed by comparing the AHI during non-rapid eye movement (NREM) (AHI(NREM)) and rapid eye movement (REM) (AHI(REM)) sleep and calculating the "REM difference" (AHI(REM) - AHI(NREM)). Additionally, each overnight polysomnographic study was classified as showing one of three mutually exclusive types of OSA: (1) mild OSA, which occurred predominantly during REM sleep (REM OSA); (2) OSA of any severity, which occurred predominantly in the supine position (S OSA); or (3) OSA without a predominance in a single sleep stage or body position (A OSA). The mean AHI(TST) for men was significantly higher than that for women (31.8 +/- 1.0 versus 20.2 +/- 1.5 events/h, p < 0. 001). The male-to-female ratio was 3.2:1 for all OSA patients, and increased from 2.2:1 for patients with mild OSA to 7.9:1 for those with severe OSA. Women had a lower AHI(NREM) than did men (14.6 +/- 1.6 versus 29.6 +/- 1.1 events/h, p < 0.001), but had a similar AHI(REM) (42.7 +/- 1.6 versus 39.9 +/- 1.2 events/h). Women had a significantly higher REM difference than did men (28.1 +/- 1.5 versus 10.3 +/- 1.1 events/h, p < 0.01). REM OSA occurred in 62% of women and 24% of men with OSA. S OSA occurred almost exclusively in men. We conclude that: (1) OSA is less severe in women because of milder OSA during NREM sleep; (2) women have a greater clustering of respiratory events during REM sleep than do men; (3) REM OSA is disproportionately more common in women than in men; and (4) S OSA is disproportionately more common in men than in women. These findings may reflect differences between the sexes in upper airway function during sleep in patients with OSA.

Female↗
PubMed1999

Promoting self-care in epilepsy: the views of patients on the advice they had received from specialists, family doctors and an epilepsy nurse.

The aim of the study was to examine patients' satisfaction with information and advice on epilepsy and self-care provided by medical specialists, general practitioners and a special nurse. We interviewed patients following a trial of nurse-run clinics for epilepsy in general practice. 44 patients, two-thirds of whom had at least one epilepsy attack in the prior 6 months were seen in their homes in the south of England. A recurring theme from interview data was that patients perceived the doctors' time as too limited to explain the condition and how to manage it, whilst the nurse had the time and expertise to do so. Overall the nurse trained in epilepsy care was valued highly for providing advice and support, especially in explaining the social aspects of epilepsy. Patients expressed the belief that they would have benefited most by seeing a special nurse at the time when epilepsy was first diagnosed.

Adolescent↗
PubMed1999

Isolation and identification of a 92-kDa stress induced protein from Candida albicans.

It was previously shown that the presence of estrogen enhances survival of Candida albicans under heat and oxidative stresses. A 92-kDa protein is inducible by heat shock and estrogen in C. albicans. Previous studies have described this protein as hsp90 because of its molecular size and heat inducibility as seen on electrophoretic gels and Western blots. In this study, ion exchange, hydroxyapatite and size exclusion chromatography were used to isolate a 92-kDa-protein band. The N-terminal sequence of isolated protein blotted onto a PVDF membrane was determined to be V-Q-S-?-V-L-G-F-P-R. This sequence is homologous to the N-terminal sequence of the MET6 gene product, cobalamin-independent methionine synthase, from Saccharomyces cerevisiae. The results of this study suggest that a cobalamin-independent methionine synthase homolog is inducible by heat and estrogen in C. albicans. This study also suggests that Candida hsp90 is more likely to exist as an 82-kDa protein as predicted by a previously described cDNA and not as a 92-kDa protein as reported in the literature.

Amino Acid Sequence↗
PubMed1999

Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients: preliminary findings.

OBJECTIVE: The authors investigated the links between depression, cardiac disease, and microcirculatory cerebral blood flow (CBF). METHOD: A magnetic resonance imaging technique based on arterial spin tagging was used to estimate microcirculatory CBF in depressed (N = 5) and comparison (N = 14) elderly subjects with coronary artery disease. Signal intensity ratios corresponding to relative microcirculatory CBF were calculated for four regions on two axial images through the upper and lower halves of the lateral ventricles. RESULTS: On the superior image, estimates of microcirculatory CBF were statistically significantly lower on the left side in the depressed subjects than in the nondepressed group. When the ratios in the superior and inferior images were averaged, the depressed subjects had lower values for both left periventricular regions of interest and the parietal region. CONCLUSIONS: Despite the small study group and indirect estimates of blood flow, these preliminary findings suggest that a relative cerebral hypoperfusion may underlie depression in elderly cardiac patients.

Age Factors↗
PubMed1999

Defining and developing professionalism.

During the development of a new occupational therapy curriculum, professionalism was identified as a core process component essential to occupational therapy practice. A group, comprised of faculty, clinicians, and students, was charged to examine professionalism and to make recommendations for curriculum planning and development. However, a consistent description or definition of professionalism was lacking in the literature. Defining professionalism was, therefore, the first task of the group. A schematic representation of professionalism was developed through a review of the literature and qualitative analysis of information obtained from discussion groups focussed on professionalism. In this paper, the schematic representation of professionalism will be presented as well as information about two supported self-study courses entitled, Fostering Professional Development and Becoming a Professional. A professional portfolio guide for the student occupational therapist will also be described. Future implications and directions for fostering professionalism will be discussed.

Canada↗
PubMed1999

Aprotinin pretreatment diminishes postischemic myocardial contractile dysfunction in dogs.

UNLABELLED: We evaluated the effect of aprotinin, administered before the onset of acute regional myocardial ischemia, on reversible contractile dysfunction induced by ischemia and reperfusion in pentobarbital-anesthetized dogs. Animals were randomized to receive either aprotinin 30,000 kallikrein inactivator units (KIU)/kg and 7000 KIU x kg(-1) x hr(-1) (n = 8) or equivalent volumes of 0.9% sodium chloride (n = 7) IV 60 min before a 15-min interruption of circumflex coronary artery blood flow and then reperfusion. There were no intra- or intergroup differences in hemodynamic variables or regional myocardial mechanics (sonomicrometry) before onset of ischemia. Immediately before reperfusion, systolic dysfunction characterized by significantly decreased percent systolic shortening was present in the circumflex coronary artery area of both study groups. After reestablishment of perfusion, aprotinin animals had preserved percent systolic shortening whereas saline animals exhibited regional systolic dysfunction. Regional myocardial contractility as assessed by the slope Mw of the preload recruitable stroke work relation was preserved during reperfusion in animals who received aprotinin but depressed in the control group. We conclude that functional recovery from myocardial ischemia-reperfusion injury at normothermia is improved by IV administration of aprotinin before the onset of acute regional myocardial ischemia in physiologically intact dogs. IMPLICATIONS: Administration of clinically relevant doses of aprotinin IV before the onset of regional myocardial ischemia, in contrast to control conditions, preserved regional systolic function and contractility at baseline values after reestablishment of myocardial perfusion in dogs.

Animals↗
PubMed1998

17-beta-estradiol upregulates the stress response in Candida albicans: implications for microbial virulence.

OBJECTIVE: The influence of 17-beta-estradiol on the stress response of Candida albicans was studied. METHODS: The survival of clinical isolates of C. albicans treated with 17-beta-estradiol after heat and oxidative stress was measured by viable plate counts. Cellular proteins were analyzed via SDS-PAGE. RESULTS: The heat stress response induced by 17-beta-estradiol in C. albicans grown at 25 degrees C protected the organisms against the lethal temperature of 48.5 degrees C, as shown by viable plate counts. 17-beta-estradiol also enhanced protection of C. albicans against oxidative stress (menadione exposure). SDS-PAGE analysis of cytoplasmic extracts revealed proteins induced by 17-beta-estradiol were similar to those induced by heat. CONCLUSION: 17-beta-estradiol enhances survival of C. albicans under heat and oxidative stresses. The proteins induced by 17-beta-estradiol are probably heat shock proteins. Because heat shock proteins are considered to be virulence factors, 17-beta-estradiol may function to promote in vivo survival.

Candida albicans↗
PubMed1998

Depression and social support in elderly patients with cardiac disease.

BACKGROUND: Depression is common among patients with cardiac disease. A number of psychosocial factors may affect the relationship between physical health and depression. There is evidence from the psychiatric literature suggesting that negative life events and social support are important factors in the development and outcome of depression. It is unknown if these factors are important in the context of depression in medically ill patients. Thus it is important to examine the relationship among social support, negative life events, and the presence of depression in elderly patients with cardiac disease. METHODS: Patients with coronary artery disease were assessed with the Duke Depression Evaluation Schedule for the Elderly. This includes the mood and anxiety disorder section of the Diagnostic Interview Schedule modified for Diagnostic and Statistical Manual of Mental Disorders diagnoses, life events, and multidimensional assessment of social support. Two hypotheses were tested: (1) the number of concurrent negative life events will be higher in patients with coronary artery disease with major depression than those without depression, and (2) social support will be less in patients with major depression than in those without. RESULTS: Presence of major depression was associated with increased negative life events and lowered subjective social support after accounting for age, sex, and race. CONCLUSIONS: The finding that subjective social support and negative life events are related to major depression suggests that even in the context of medical illness, social factors are still important in the development of major depression.

Aged↗
PubMed1998

Experience with antegrade bihemispheric cerebral perfusion in aortic arch operations.

BACKGROUND: Various techniques have been used for cerebral protection in aortic arch operations. Antegrade cerebral perfusion has lost its popularity to hypothermic circulatory arrest to overcome the so-called cluttered operative field. Hypothermic circulatory arrest has its own problems of coagulopathy, time constraints, and prolongation of cardiopulmonary bypass time. METHODS: Since June 1986 we have used antegrade bihemispheric cerebral perfusion with moderate hypothermia in 20 patients with aortic arch disease. Twelve patients had aneurysm, 7 had dissection, and 1 had traumatic tear. Five patients had had previous sternotomy for ascending aortic replacement. In addition to arch reconstruction, 7 patients had aortic valve replacement or repair, 2 patients had Bentall procedure, and 3 had selective innominate reconstruction. The mean cerebral perfusion time was 51+/-29 minutes. In 7 patients the cerebral perfusion time was between 60 and 120 minutes. RESULTS: There was no in-hospital or 30-day mortality. The blood product requirements were significantly less with moderate hypothermia. One patient suffered cerebrovascular accident (5%). None of the 7 patients with cerebral perfusion times of 60 to 120 minutes had any neurologic deficits. These results are superior to those reported for hypothermic circulatory arrest with or without retrograde cerebral perfusion. CONCLUSIONS: Antegrade bihemispheric cerebral perfusion is an optimal adjunct for cerebral protection during aortic arch operations.

Adolescent↗
PubMed1998

Specificity of electrocardiographic myocardial infarction screening criteria in patients with nonischemic cardiomyopathies.

BACKGROUND: The 32-point, 54-criteria Selvester QRS scoring system has been successfully used to estimate the size of nonacute myocardial infarction (MI). Three criteria of the system have been shown to be sensitive for the identification of nonacute MI and specific in normal control subjects. The validity of the system has not been tested in patients with cardiomyopathy of nonischemic origin. The purpose of this study was to examine the electrocardiographs (ECGs) of patients with abnormal left ventricular function but no presence of coronary disease to determine the diagnostic specificity of the MI screening criteria subset of the Selvester QRS scoring system. METHODS AND RESULTS: Six hundred ninety patients were considered. Exclusion criteria included age <10 years, cardiac transplantation, thrombolytic therapy, any angiographic evidence of coronary disease, left ventricular ejection fraction (LVEF) >60%, or history of myocardial revascularization. ECG exclusion criteria included left ventricular hypertrophy, right ventricular hypertrophy, left bundle branch block, right bundle branch block, ventricular pacing, left anterior fascicular block, left posterior fascicular block, ventricular preexcitation, and low voltage, because these confounding factors could mimic an infarct on the ECG. The 261 remaining patients were then examined for the presence of the MI screening criteria subset: (1) inferior location: Q > or =30 msec in aVF, (2) anterior location: either any Q or R< or =0.1 mV and < or =10 msec in V2, and (3) posterior location: R> or =40 msec in V1. Thirty-two of the 261 patients falsely met at least 1 of the 3 MI screening criteria, resulting in an overall specificity of 88% (vs 95% in normal control subjects, P=.0006). A specificity of 98% (n = 256) was achieved for the inferior MI screening criterion alone, whereas the anterior and posterior MI screening criteria alone achieved significantly lower specificities: 94% (n = 245) and 95% (n = 249), respectively. When the patient population was divided into LVEF <30% and LVEF > or =30%, no significant association was found between MI screening criteria and LVEF with specificities of 87% and 88%, respectively, for the 2 groups (P= .34). CONCLUSIONS: The MI screening criteria subset is relatively specific in patients with nonischemic cardiomyopathy, falsely identifying only 12% with nonacute MI. However, this specificity is lower than the 95% achieved in normal subjects. Regional accumulation of scarring caused by cardiomyopathy could result in false-positive indication of MI in the present population. Another possibility could be that some patients could have hypertrophy of the myocardium insufficient to produce positive ECG criteria for left ventricular hypertrophy or right ventricular hypertrophy but sufficient to mimic infarction.

Adult↗
PubMed1997

Stress management and exercise training in cardiac patients with myocardial ischemia. Effects on prognosis and evaluation of mechanisms.

BACKGROUND: Previous studies have demonstrated that myocardial ischemia can be elicited by mental stress in the laboratory and during daily life and that ischemia induced by mental stress is associated with an increased risk for future cardiac events in patients with coronary artery disease. OBJECTIVES: To examine the extent to which ischemia induced by mental stress can be modified by exercise stress management, and to evaluate the impact of these interventions on clinical outcomes. METHODS: One hundred seven patients with coronary artery disease and ischemia documented during mental stress testing or ambulatory electrocardiographic monitoring were randomly assigned to a 4-month program of exercise or stress management training. Patients living at a distance from the facility formed a nonrandom, usual care comparison group. Myocardial ischemia was reassessed following treatment, and patients were contacted annually for as long as 5 years to document cardiac events, including death, nonfatal myocardial infarction, and cardiac revascularization procedures. RESULTS: Twenty-two patients (21%) experienced at least 1 cardiac event during a mean (+/- SD) follow-up period of 38 +/- 17 months. Stress management was associated with a relative risk of 0.26 compared with controls. The relative risk for the exercise group also was lower than that of controls, but the effect did not reach statistical significance. Stress management also was associated with reduced ischemia induced by mental stress and ambulatory ischemia. CONCLUSION: These data suggest that behavioral interventions offer additional benefit over and above usual medical care in cardiac patients with evidence of myocardial ischemia.

Adult↗
PubMed1997

Stability over time of circadian rhythm of variability of heart rate in patients with stable coronary artery disease.

Reproducibility of circadian rhythm of variability in heart rate was studied in 40 patients with stable coronary artery disease who underwent 48-hour ambulatory electrocardiographic recordings at baseline (time 1) and after 4 months (time 2). The standard deviation of the R-R interval and the low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.45 Hz) components of variability in heart rate were assessed every 5 minutes. In 35 patients a significant circadian rhythm was observed at both time 1 and time 2 in the standard deviation of the R-R interval, with the acrophase occurring at around 5:00 AM, in the high-frequency amplitude with the acrophase around 3:00 AM, and in the low-frequency/high-frequency ratio with the acrophase around noon. In these patients, parameters of circadian rhythm (mesor, amplitude, and acrophase) showed good within-individual reproducibility with an intraclass correlation coefficient of 0.63 to 0.95 (p < 0.001 for all). In the patients who showed inconsistency about the significance of circadian rhythm between time 1 or time 2, the amplitude of circadian rhythm, even if significant, was found in the lowest five values in the distribution. We conclude that the circadian rhythms of cardiac autonomic activity are stable over time within individual patients with stable coronary artery disease.

Adult↗
PubMed1997

Molecular phylogenetics of a protein repair methyltransferase.

Protein-L-isoaspartyl (D-aspartyl) O-methyltransferase (E.C. 2.1.1.77) is a well-conserved and widely distributed protein repair enzyme that methylates isomerized or racemized aspartyl residues in age-damaged proteins. We exploited the availability of protein sequences from 10 diverse animal, plant and bacterial taxa to construct a phylogenetic tree and determine the rates of amino acid substitution for this enzyme. We used a likelihood ratio test to show that this enzyme fulfills the conditions for a molecular clock. We found that the rate of substitution is 0.39 amino acid substitutions per site per 10(9) years and remains relatively constant from bacteria to humans. We argue that this degree of sequence conservation may result from the functional constraints necessitated by the requirement to specifically recognize altered aspartyl but not normal aspartyl residues in proteins. Relative rate analysis of the Caenorhabditis elegans sequence suggests that the amino acid substitution rate in the nematode lineage may be higher than that in other lineages and that the divergence of nematodes may have been a more recent event than suggested by previous analysis.

Amino Acid Sequence↗