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Biomedical subjects

M L Fox

Publications and source records attributed to M L Fox.

At least 19 recordsLinked to original sources
PubMed2001

Circulating monocyte-platelet aggregates are an early marker of acute myocardial infarction.

OBJECTIVES: We investigated whether elevated levels of circulating monocyte-platelet aggregates (MPA) can be used to identify patients with acute myocardial infarction (AMI). BACKGROUND: Commonly used blood markers of AMI reflect myocardial cell death, but do not reflect the earlier pathophysiologic processes of plaque rupture, platelet activation and resultant thrombus formation. Circulating MPA form after platelet activation. METHODS: In a single center between October 1998 and November 1999, we measured circulating MPA in a blinded fashion by whole blood flow cytometry in 211 consecutive patients who presented to the emergency department (ED) with chest pain and were admitted to rule out AMI. Acute myocardial infarction was diagnosed by a CK-MB fraction greater than three times control. RESULTS: Patients with AMI (n = 61), as compared with those without AMI (n = 150), had significantly higher numbers of circulating MPA (11.6 +/- 11.4 vs. 6.4 +/- 3.6, mean +/- SD, p < 0.0001). After controlling for age, the adjusted odds of developing AMI for patients in the 2nd, 3rd and 4th quartiles of MPA, in comparison with patients in the lowest quartile (odds ratio = 1.0), were 2.1 (95% confidence interval [CI]: 0.7, 6.8), 4.4 (95% CI: 1.5, 13.1) and 10.8 (95% CI: 3.6, 32.0), respectively. The number of circulating MPA in patients with AMI presenting within 4 h of symptom onset (14.4) was significantly greater than those presenting after 4 h (9.4) and after 8 h (7.0), (p < 0.001). Of the 61 patients with AMI, 35 (57%) had a normal creatine kinase isoenzyme ratio at the time of presentation to the ED, but had high levels of circulating MPA (13.3). CONCLUSIONS: Circulating MPA are an early marker of AMI.

Creatine Kinase↗
PubMed2001

Explaining employees' health care costs: a prospective examination of stressful job demands, personal control, and physiological reactivity.

The authors tested the ability of stressful demands and personal control in the workplace to predict employees' subsequent health care costs in a sample of 105 full-time nurses. Both subjective and objective measures of workload demands interacted with personal control perceptions in predicting the cumulative health care costs over the ensuing 5-year period. Tonic elevations in salivary cortisol, moreover, mediated the effects of demands and control on health care costs. Neither the job demands variables nor physiological reactivity measures, however, explained subsequent mental health. The results support findings from the epidemiological literature that demonstrate an important role for employees' control in explaining occupational inequalities in coronary heart disease and mortality. The authors argue that the results also encourage control-enhancing job design interventions by suggesting that their outcomes can benefit both organizations and their members.

Adult↗
PubMed2001

Leukocyte-platelet aggregation, platelet surface P-selectin, and platelet surface glycoprotein IIIa after percutaneous coronary intervention: Effects of dalteparin or unfractionated heparin in combination with abciximab.

BACKGROUND: Plaque disruption with resultant platelet activation and leukocyte-platelet aggregation is a pathophysiologic process common to both acute coronary syndromes and percutaneous coronary interventions. Unfractionated heparin is a standard antithrombotic therapy in patients with both acute coronary syndromes and in those undergoing percutaneous coronary interventions. Low-molecular-weight heparins have been reported to cause less platelet activation than unfractionated heparin. METHODS: Monocyte-platelet aggregates, neutrophil-platelet aggregates, platelet surface P-selectin, and platelet surface glycoprotein (GP) IIIa were measured serially by whole blood flow cytometry in 40 patients with unstable angina (randomly assigned to either unfractionated heparin 70 U/kg or the low-molecular-weight heparin dalteparin 60 IU/kg) undergoing coronary intervention with planned abciximab administration (in 2, one-half-dose boluses). Assays were performed at baseline, 5 minutes after administration of either type of heparin, 10 minutes after the first bolus of abciximab, 10 minutes after second bolus of abciximab, and 8 to 10 and 16 to 24 hours after administration of either heparin. RESULTS: No significant differences in clinical outcomes were observed between patients receiving either unfractionated heparin or dalteparin. The number of circulating P-selectin-positive platelets was increased by unfractionated heparin but not dalteparin, and abciximab reversed this increase. The number of circulating P-selectin-positive platelets was reduced below baseline levels in both treatment groups 8 to 10 and 16 to 24 hours after study drug administration. At 8 to 10 and 16 to 24 hours after administration of study drug, platelet degranulation in response to iso-thrombin receptor agonist peptide 1.5 mmol/L was significantly reduced by almost 50% (compared with immediately after study drug administration). Both unfractionated heparin and dalteparin significantly increased the numbers of circulating monocyte-platelet and neutrophil-platelet aggregates, which were subsequently reduced to baseline levels after administration of the second abciximab bolus and to below baseline at both 8 to 10 and 16 to 24 hours in all patients. After both unfractionated heparin and dalteparin administration, platelet surface GP IIIa expression was significantly increased compared with baseline at both 8 to 10 and 16 to 24 hours. CONCLUSIONS: Dalteparin in combination with abciximab in patients with unstable angina undergoing coronary intervention appears to be safe. Unfractionated heparin, but not dalteparin, degranulates platelets in patients with unstable angina. Both heparins increase the number of circulating monocyte-platelet and neutrophil-platelet aggregates. Abciximab therapy during coronary interventions rapidly reduces the number of degranulated platelets and leukocyte-platelet aggregates.

Abciximab↗
PubMed2000

Resistance to multiple fluoroquinolones in a clinical isolate of Streptococcus pyogenes: identification of gyrA and parC and specification of point mutations associated with resistance.

A strain of Streptococcus pyogenes resistant to multiple fluoroquinolones was isolated from the blood of an immunocompromised patient. Resistance to fluoroquinolones in S. pyogenes has not been previously studied. Compared to 10 sensitive strains of S. pyogenes, the fluoroquinolone-resistant clinical isolate of S. pyogenes presented point mutations in gyrA, predicting that serine-81 was changed to phenylalanine and that methionine-99 was changed to leucine, and in parC, predicting that serine-79 was changed to tyrosine. The mechanism of fluoroquinolone resistance in this isolate of S. pyogenes appears to be analogous to previously reported mechanisms for Streptococcus pneumoniae.

Anti-Infective Agents↗
PubMed2000

Validation of an outcome scale for use in adult psychiatric practice.

OBJECTIVE: To clarify the usefulness, acceptability, sensitivity, and validity of version 4 of the Health of the Nation Outcome Scale (HoNOS), a scale developed to meet the requirement for a clinically acceptable outcome scale for routine use in mental illness services. DESIGN: Patients with a range of mental illnesses were rated on the HoNOS at the beginning and end of an episode by interviews with mental health professionals. SUBJECTS: 934 patients from eight diagnostic categories were rated by 129 mental health professionals at 17 sites; 250 were also rated on a range of comparison scales. OUTCOME MEASURES: Comparison of patients' scores at the beginning and end of an episode using individual item scores, dimensional subscores, and the total score. RESULTS: HoNOS scores decreased by almost 50% between the beginning and end of episodes. They varied with the severity of the setting and discriminant analysis showed that the HoNOS had a moderate level of discriminatory power. Correlation analysis showed acceptable levels of agreement with independent scales, although the accuracy of ratings of some items at the beginning of an episode was affected by information deficits. CONCLUSION: The findings indicate that HoNOS is sensitive to change across time and to differences in illness type and severity, and has a sufficient degree of both construct and criterion related validity to fulfil the requirements of a mental health outcome scale for routine use in clinical settings.

Adult↗
PubMed1999

An investigation of the effects of time and involvement in the relationship between stressors and work-family conflict.

Previous researchers have proposed that the time and energy involved in family and paid work should affect the relationship between stressors and conflict in both the work and family domains. Using a sample of 113 registered nurses, the authors hypothesized that the amount of time and involvement in both domains would moderate the stressor-conflict relationships. Results supported many of the interactions in predicting conflict in each domain, and implications for the health of working women with family responsibilities were discussed.

Adaptation, Psychological↗
PubMed1997

The influence of cardiopulmonary bypass on ionized magnesium in neonates, infants, and children undergoing repair of congenital heart lesions.

The purpose of this study was to measure the ionized magnesium (iMg) concentrations in children undergoing the correction of congenital heart defects. iMg levels were measured in 115 consecutive patients at five sample periods: prebypass, onset of bypass, during rewarming, immediately postbypass, and 1 h postbypass using an ion-selective electrode of the NOVA-CRT 8 (Nova Biomedical, Watham, MA). The incidence of dysrythmias was noted. Patients were divided into two groups: those who received Plegisol as the cardioplegic solution and those who did not. This study demonstrates that iMg decreases with the onset of cardiopulmonary bypass (CPB) in patients who weigh < 10 kg. In the Plegisol group, all subgroups of patients demonstrated statistically higher iMg during the rewarming phase of CPB, immediately post-CPB, and 1 h post-CPB, when compared with control values. The probability of dysrhythmias in the Plegisol group was almost twice that of the non-Plegisol group. However, this did not reach statistical significance (P = 0.22). The results of our study demonstrate that the use of CPB on pediatric patients produces alterations in the iMg. The changes differ depending on both patient weight and the use of a magnesium-containing cardioplegic solution, exemplified here by Plegisol. The role of these changes in iMg on dysrhythmias could not be further evaluated.

Adolescent↗
PubMed1997

Modulation of NK cell cytolytic activity by macrophages in chronically exercise-stressed mice.

This study was designed to investigate the effects of moderate-intensity endurance training on basal natural killer (NK) cell cytolytic activity in murine splenocytes that were enriched for 1) NK1.1+ cells or 2) macrophages and NK1.1+ cells. Mice were assigned to sedentary (Sed), treadmill control (TM), or treadmill-trained (Trn) groups. Splenocyte number, the percentages of NK1.1+, large granular lymphocytes (NK1.1+, LGL-1+), and other subpopulations did not change in Trn mice. Approximately 70% of cells enriched for NK1.1+ expressed this surface antigen. Lytic units (LU) expressed per LGL-1+ cell were significantly lower in Trn [83.9 +/- 3.2 (SE)] compared with Sed (109.5 +/- 7.5) and TM (101.3 +/- 6.4) groups. When macrophages remained in the in vitro assay, LU per LGL-1(+) cell did not differ across groups. The results indicate that highly enriched NK1.1+ cells from Trn mice had lower NK cell activity compared with Sed mice. No differences in NK cell activity were observed when cells were enriched for NK1.1+ cells and macrophages. These findings support the hypothesis that macrophage modulation of NK cells may be one mechanism contributing to augmented basal NK cell activity in endurance-trained individuals.

Animals↗
PubMed1995

Paediatric cardiac catheterization: innovations.

In recent years interventional procedures have been introduced to the field of paediatric cardiac catheterization. These procedures continue to develop in complexity and increasingly are being applied to patients with reduced cardiovascular reserve, as an alternative to cardiac surgery or when cardiac surgery with cardiopulmonary bypass is contraindicated. More frequently anaesthetists are being called upon to provide support in sedating, anaesthetizing or/and resuscitating these patients. The purpose of this review is to give a comprehensive update of the interventional procedures and to review the anaesthetic management techniques as they apply to the catheterization laboratory. We will discuss possible complications and management strategies from our own experience and the experience of others. We have observed that as more complicated procedures are performed the anaesthetist plays a pivotal role in the management of the patient from arrival to departure from the cardiac catheterization laboratory, and in preventing mortality and major morbidity. Although the economic consequences of interventional cardiological techniques remain unclear, the field continues to expand and more complex procedures are continually being introduced.

Anesthesia, General↗
PubMed1995

Transcatheter closure of ventricular septal defects: hemodynamic instability and anesthetic management.

The technique of transcatheter ventricular septal defect (VSD) device closure may be associated with significant hemodynamic instability. The anesthetic records and catheterization data of 70 consecutive transcatheter VSD closures between February 1989 and September 1992 were reviewed, and risk factors associated with hemodynamic instability evaluated. In 28 of 70 procedures (40%), hypotension (> 20% decrease in systolic blood pressure from baseline) occurred; 12 responded to administration of fluids intravascularly alone, whereas 16 patients required additional acute resuscitation. Significant dysrhythmias occurred during 20 (28.5%) anesthetics associated with hypotension and requiring treatment or catheter withdrawal. ASA physical status, precatheterization indication for device placement, and patient size were not predictive of hemodynamic instability during the procedure. Blood transfusions were necessary in 38 (54.4%) cases and were size-related, with patients weighing less than 10 kg requiring a significantly larger transfusion volume (25.1 +/- 12.4 mL/kg). After 35 procedures (50%) patients were admitted directly to the intensive care unit (ICU) due primarily to hemodynamic instability or procedure duration; 24 (68%) required mechanical ventilation. No deaths occurred; there was no late morbidity due to catheterization-related events. Intravenous sedation was used for the initial catheterizations, maintained with a combination of midazolam, ketamine, and morphine. Subsequently general intravenous or inhaled anesthesia was predominantly used during transesophageal echocardiography and internal jugular vein cannulation. We conclude that hemodynamic instability is common during device closure of VSDs, and is likely to be an inescapable feature of these procedures in many patients because of the technique necessary for device placement.

Anesthesia↗
PubMed1995

Patient satisfaction and experience with health services and quality of care.

This article discusses the use of patient satisfaction and personal health care experiences as a measure of health care quality. It also presents a field-proven patient experience and satisfaction assessment methodology known as the Patient Experience Survey (PES) that has been employed throughout the country for the last decade. Finally, it offers recommendations and comments on the use of patient satisfaction data in quality assessment and improvement.

Data Interpretation, Statistical↗
PubMed1993

Effects of stressful job demands and control on physiological and attitudinal outcomes in a hospital setting.

We tested the job demands--job control model of stress with a group of 136 registered nurses. Significant interactions between subjective and objective measures of work load and a measure of perceived control predicting physiological and attitudinal outcomes indicated support for the model. In addition, objectively assessed job demands were significantly associated with blood pressure and cortisol levels. The model also predicted elevations in physiological responses after individuals left work, suggesting that potentially health-impairing reactions to jobs that have high demands and low controllability might carry over to home settings and thus pose a high risk of long-term health impairment. The results have implications for the role of personal control in occupational stress generally and for nurse-management practices specifically.

Adult↗
PubMed1993

Patterns of alcohol and drug use among women: focus on special populations.

Despite the growing national concern about the effect of the use of alcohol and other drugs on the health and productivity of men and women, relatively little is know about alcohol and other drug (AOD) problems in women. Because of this lack of research and the stigma associated with women who are alcoholic or drug addicted, AOD problems among women are less likely to be recognized and addressed. This article reviews patterns and consequences of AOD use among a number of special populations of women. Information about risk factors and assessment and screening are included to assist the nurse in the identification, counseling, and referral of women with AOD-related problems.

Alcoholism↗
PubMed1992

Dispositional affect and work-related stress.

Trait negative affectivity (NA) has been asserted to be a factor that spuriously inflates relationships between self-reported stressors and self-reported strain outcomes. We tested this hypothesis with conventional work stress instrument responses and physiological assessments obtained from 311 fire and police department employees. Confirmatory factor analyses indicated that NA did not measure a factor in common with measures of subjective strain. Latent-variable structural equations analyses, however, found that estimating the effects of NA on strain significantly attenuated the effects of work stressors. NA had no correlation with physiological stress outcomes. Trait positive affectivity did not attenuate relationships between work stressors and either subjective or objective stress outcomes. Implications for work stress research methodology and recommendations are discussed.

Adaptation, Psychological↗
PubMed1992

Decision-making autonomy in nursing.

Current nursing literature has suggested that nurses may have low needs or preferences for decision-making autonomy. In this study, the authors found that nurses differed in their preferences for decision-making autonomy in three types of work-related decisions. Employed nurses with a greater preference for autonomy were more satisfied with their jobs, and those with little or no such preference were less satisfied, as they gained decision-making influence over patient care and unit management. The authors discuss implications for designing and implementing decision-making programs.

Adult↗
PubMed1992

Transcatheter closure of atrial septal defects: hemodynamic complications and anesthetic management.

Transcatheter closure of atrial septal defects using a double-umbrella (clamshell) device can now be performed during an overnight hospital stay with little morbidity and no mortality. The initial 2-yr experience with anesthetic care for the procedure was collected and subsequently analyzed. Primary anesthetic care was given in 118 cases and urgent anesthetic intervention was required in another four cases. Anesthesia with spontaneous ventilation in patients with unprotected airways using intravenous ketamine and midazolam (average cumulative doses 1.4 and 0.17 mg.kg-1.h-1, respectively) was used in 93 cases (77%); mean maximum PaCO2 value was 41 +/- 6 mm Hg. In 29 patients (23%) tracheal intubation and muscle paralysis were used to facilitate control of airway and ventilation. Anesthetic-related complications occurred in three patients: ventilatory compromise developed in two patients in the spontaneous ventilation group and one patient experienced awareness during endotracheal anesthesia with paralysis. Procedural complications that altered anesthetic management were more frequent, including embolization of the clamshell device requiring surgical retrieval in two of six embolizations, intracardiac air embolization (four cases), tricuspid regurgitation (one case), device malplacement requiring late operation (one case), and transient brachial plexus injury (three cases). Anesthesia for transcatheter atrial septal defect closure allows precise device placement, prompt control of hemodynamic complications, and transesophageal echocardiographic monitoring of device placement. Although general anesthesia with spontaneous ventilation using ketamine and midazolam was usually safe and effective, tracheal intubation for control of airway and ventilation was sometimes necessary for safety and for optimal operating conditions. Familiarity with transcatheter closure techniques and close communication with the catheterization team is essential to minimize and treat associated complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Conjunctival flaps in the treatment of refractory pseudomonas corneal abscess.

Pseudomonas corneal abscess can result in a rapid downhill clinical course despite institution of appropriate medical measures. In this situation the clinician is faced with surgical intervention. A series of patients treated and stabilized through conjunctival flap therapy are presented. The role of conjunctival flap therapy in halting the progression of this entity is described.

Abscess↗