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Biomedical subjects

E Powers

Publications and source records attributed to E Powers.

12 recordsLinked to original sources
PubMed2001

Kinetics of phthalate reactions with ammonium hydroxide in aqueous matrix.

Common phthalate pollutants, such as dimethyl phthalate and diethyl phthalate found in aqueous environmental matrices react with ammonium hydroxide at ordinary temperatures exhibiting an overall reaction order in the range 1.3-1.4. While the reaction is of first order with respect to the phthalate, the order of reaction is fractional in ammonium hydroxide. The rate constants for the reactions of these two phthalates in alkaline waters at ambient temperatures are in the range 1.3 x 10(-4) and 8.5 x 10(-5) Lx/mol s. Under these conditions the estimated half-lives for dimethyl phthalate and diethyl phthalate at a concentration of each at 20 mg/L is 4.5 and 14 h, respectively. Other phthalates are expected to exhibit similar kinetics in their base hydrolysis with NH4OH. Thus, the presence of both the phthalate esters and ammonia or ammonium salts in the water under alkaline conditions may result in their self-removal by hydrolysis.

Ammonium Hydroxide↗
PubMed1997

Vision for a treasured resource. Part 1, Nurse manager role implementation.

The importance of the nurse manager for both quality patient care and organizational effectiveness seems indisputable. With decentralized decision-making, the role of the nurse manager has expanded in both scope and accountability. In this two-part article, role implementation of the nurse manager and associated learning needs are described. This article focuses on interpreting significant incidents related to role implementation in nurse managers' practice. It also shows how the authors used the Manager as Developer Model for organizing and understanding some of the data. Part 2 (April 1997) will describe and interpret significant incidents related to nurse managers' ongoing learning needs.

Boston↗
PubMed1997

Vision for a treasured resource. Part 2. Nurse manager learning needs.

Part 1 in this two-part series focused on the meaning of significant incidents in nurse managers' practice related to role implementation. Explanation of the authors' application of the Manager as Developer Model (MADM) as a useful model for organizing and understanding some of the data was also discussed. Part 2 describes significant incidents in nurse managers' practice related to their ongoing learning needs. The authors address issues of performance counseling and intervention versus coaching and make recommendations for management development programs.

Boston↗
PubMed1996

Reducing time in bed after cardiac catheterization (TIBS II)

BACKGROUND: More than 500,000 cardiac catheterizations are done annually in the United States for both the diagnosis and treatment of patients with coronary artery disease. A femoral artery catheter insertion site is usually used for these procedures, and postprocedure protocols call for prolonged bed rest with restricted patient movement. Time-in-bed standards vary widely, from 3 to 12 hours after cardiac catheterization to more than 24 hours of bed rest after angioplasty. Bed rest with restricted movement causes patient discomfort, increases nursing workload, and prolongs length of hospital stay. OBJECTIVE: To determine if there would be a significant difference in the incidence of bleeding from femoral artery insertion sites between cardiac catheterization patients who remained in bed for 4 hours and those who remained in bed for 6 hours after sheath removal. METHODS: An experimental-control group design was used with a convenience sample (N = 86) of adult patients undergoing diagnostic coronary angiography. Patients were randomly assigned to remain in bed for 4 hours (experimental) or 6 hours (control) after arterial sheath removal. Both groups had pressure dressings and sandbags in place over the insertion site during time in bed. RESULTS: There was no significant difference in the incidence of bleeding related to out-of-bed activity between the groups (chi-square = .31, df = 1). CONCLUSIONS: Requisite time in bed after cardiac catheterization can be safely decreased from 6 to 4 hours. This change has implications for enhancing patient comfort and decreasing both length of hospital stay and healthcare costs.

Aged↗
PubMed1991

Implementation of a local area network for nursing management.

This paper describes the planning and implementation of a Local Area Network (LAN) for the nursing service of a 504-bed urban teaching hospital. The major goals of the network were: support for nurse executives, nurse managers, and the departmental assistants assigned to administrative offices; increased efficiency and effectiveness of the nursing administrative areas; and improved communication systems. Collaboration between the nursing service and the Computer Information Center (CIC) resulted in a network of over 70 workstations, spanning 11 buildings. The network provides access to multiple programs that support clinical, managerial, and research activities. Gateways provide access to the hospital's two mainframes.

Boston↗
PubMed1990

Altered rheological properties of blood following administrations of tissue plasminogen activator and streptokinase in patients with acute myocardial infarction.

Tissue blood flow is determined by rheological properties of blood as well as by vascular resistance. In acute myocardial infarction patients who participated in the TIMI I trial, we compared the effects of recombinant tissue plasminogen activator (rt-PA) and streptokinase (SK) on blood rheological properties and plasma fibrinogen concentration. Blood viscosity was determined by using a coaxial cylinder viscometer at shear rates, gamma, of 0.01-200 sec-1. Red blood cell (RBC) deformability was studied by filtration through polycarbonate microsieves with pore size of 3 and 5 microns. Therapy with rt-PA resulted in slight decreases but statistically significant in blood viscosity from 5.2 +/- 0.5 to 4.9 +/- 0.4 cP (gamma = 52 sec-1), plasma viscosity from 1.36 +/- 0.09 to 1.32 +/- 0.06 cP, and plasma fibrinogen from 0.26 +/- 0.04 to 0.21 +/- 0.03 g/dl. SK therapy resulted in reductions in blood viscosity from 5.1 +/- 0.5 to 4.6 +/- 0.3 cP, plasma viscosity from 1.26 +/- 0.10 to 1.16 +/- 0.03 cP, and fibrinogen from 0.26 +/- 0.06 to 0.10 +/- 0.05 g/dl. Changes observed with SK were significantly greater than those observed with rt-PA (all p less than 0.05), and the differences persisted at 10 days after thrombolytic therapy. RBC deformability was similar in the two groups. The greater reduction of blood viscosity after SK than rt-PA suggests that, for a given degree of arterial patency, myocardial blood flow may be better maintained with SK than rt-PA in patients with acute myocardial infarction.

Blood Proteins↗
PubMed1989

Short- and long-acting angiotensin-converting enzyme inhibitors: a randomized trial of lisinopril versus captopril in the treatment of congestive heart failure. The Multicenter Lisinopril-Captopril Congestive Heart Failure Study Group.

A randomized, parallel, double-blind study was performed with lisinopril, a long-acting angiotensin-converting enzyme inhibitor, versus captopril, a shorter-acting angiotensin-converting enzyme inhibitor, in the treatment of congestive heart failure. All patients were in New York Heart Association class II, III or IV and had remained symptomatic despite therapy with digoxin and diuretics. After a 4 to 14 day placebo baseline period, patients were randomized to receive either lisinopril, 5 mg orally once per day (n = 94), or captopril, 12.5 mg orally three times per day (n = 95), in addition to continuation of digoxin and diuretics. The dose of study drug could be doubled at 4 week intervals for a total of 12 weeks of double-blind therapy. The maximal dose was 20 mg once per day of lisinopril or 50 mg three times per day of captopril. The addition of either lisinopril or captopril to a regimen of diuretics or digoxin, or both, caused an increase in exercise duration as assessed on a motorized treadmill. When protocol violators were excluded, patients receiving lisinopril had a statistically greater increase in exercise duration than that of patients receiving captopril. In patients with renal impairment (serum creatinine greater than 1.6 mg/dl at baseline), lisinopril was superior to captopril in improving exercise duration. Lisinopril, but not captopril, increased left ventricular ejection fraction in patients with moderately to severely (less than 35%) decreased function (p less than 0.05). Improvement in functional capacity and quality of life, as assessed by the Yale Scale dyspnea/fatigue index, was significantly greater for the lisinopril group.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

Effect of end-diastolic volume on the canine left ventricular ejection fraction.

Left ventricular ejection fraction is commonly used in the clinical assessment of ventricular function. However, the effect of changes in end-diastolic volume on ejection fraction is controversial. The present study examines the effect of changes in end-diastolic volume on ejection fraction in 26 anesthetized dogs on right heart bypass with controlled hemodynamics. At the end of each experiment, pressure-volume relationships were obtained in the potassium arrested heart following suturing of the mitral valve leaflets and clamping of the aortic root. This technique allowed determination of the end-diastolic volume from the end-diastolic pressure. Ejection fraction is highly dependent on end-diastolic volume and end-diastolic pressure at lower levels of end-diastolic volume and end-diastolic pressure. Ejection fraction increased from 30 +/- 1% (SEM) to 64 +/- 2% (p less than 0.001) when end-diastolic pressure was increased from 4 +/- 0.5 to 11 +/- 0.5 cm H2O. The corresponding end-diastolic volumes were 22 +/- 0.5 and 38 +/- 1 ml, respectively (p less than 0.01). Ejection fraction only increased from 64 +/- 2% to 71 +/- 1% (p less than 0.01) when end-diastolic pressure was increased from 11 +/- 0.5 to 18 +/- 1 cm H2O. The corresponding end-diastolic volumes were 38 +/- 1 and 50 +/- 1 ml (p less than 0.01), respectively. This dependence of ejection fraction on preload is present over a wide range of levels of aortic pressure. Similar directional changes in ejection fraction with preload were present after an adequate autonomic blockade, in the presence of either increased or decreased inotropic state and in the presence of an open or closed pericardium. Thus, the present study demonstrates that ejection fraction can be substantially altered by acute changes in end-diastolic volume. This factor should be taken into account when using ejection fraction for the clinical assessment of ventricular function.

Animals↗
PubMed1979

No evidence for chromosomal mosaicism in multiple tissues of 10 patients with 45, XO Turner syndrome.

Why the frequency of spontaneous abortions among monosomy X conceptuses is 98% while the postnatal course of Turner syndrome is relatively benign has not been understood. One explanation could be that mosaicism for a euploid cell line confers viability and that those 2% of 45,XO zygotes surviving in utero have some degree of mosaicism. We thus reasoned that if the non-mosaic 45,XO karyotype is lethal, a thorough study of living Turner syndrome patients might reveal a much higher frequency of mosaicism than the 30--40% reported. Ten adult women with a 45,XO leukocyte karyotype were investigated, looking at five tissue types from all three germ layers: buccal mucosa and hair from ectoderm, urinary epithelium from endoderm and ectoderm, and lymphocytes and skin fibroblasts from mesoderm. We were unable to confirm mosaicism in these patients, although in 2 out of 10 there was the suggestion of a small percentage of euploid cells in skin and blood karyotypes.

Abortion, Spontaneous↗
PubMedDate not supplied

Gene exchange in a ground cricket hybrid zone.

The ground crickets Allonemobius fasciatus and A. socius (Orthoptera: Gryllidae) are sister species that form a mosaic hybrid zone in the eastern United States. The genetic structure of the hybrid zone has been studied extensively by the use of protein electrophoresis. Here, we report the discovery of several random amplification of polymorphic DNA (RAPD) markers that distinguish the two species, and we assess the congruence of RAPD markers and protein markers with regard to the identification of hybrids in mixed populations. Both sets of markers indicate that gene flow between A. fasciatus and A. socius is quite limited.

Animals↗