Biomedical subjects

E McFalls

Publications and source records attributed to E McFalls.

4 recordsLinked to original sources

PubMed1998

Ion-exchange column chromatographic method for assaying purine metabolic pathway enzymes.

High energy phosphate levels fall rapidly during cardiac ischemia and recover slowly (more than one week) during reperfusion. The slow recovery of ATP may reflect a lack of purine metabolic precursors and/or increased activity of purine catabolic enzymes such as 5'-nucleotidase (5'-NT, EC 3.1.3.5) and adenosine deaminase (ADA, EC 3.5.4.4). The activity of enzymes involved in both the catabolism of ATP precursors (5-NT and ADA) and the restoration of ATP from slow synthetic pathways [adenosine kinase (AK, EC 2.7.1.20), adenine phosphoribosyl transferase (APRT, EC 2.4.2.7) and hypoxanthine phosphoribosyl transferase (HPRT, EC 2.4.2.8)] may directly affect the rate of ATP recovery. Strategies to enhance recovery will depend on the relative activity of these enzymes following ischemia. Their activity in different species and their response to ischemia are not well characterized. Hence, rapid assay methods for these enzymes would facilitate detailed time course studies of their activities in postischemic myocardium. We modified a single ion-exchange column chromatographic method using DEAE-Sephadex to determine the products of incubation of 5'-NT, AK, APRT and HPRT with their respective substrates. The uniformity of the final product measurement procedure for all assays permits the activities of the four enzymes to be rapidly determined in a single tissue sample and facilitates the study of a large number of samples. This technique should also be useful for enzymes of the pyrimidine metabolic pathway.

5'-Nucleotidase↗

PubMed1998

Coronary bypass grafting for single-vessel coronary artery disease: a 17-year review with short- and long-term follow-up.

STUDY OBJECTIVES: We reviewed our short- (30 days) and long-term (up to 17 years) experience with surgical revascularization for patients with angiographically documented isolated single-vessel coronary artery disease. DESIGN: Retrospective study of single-vessel coronary artery bypass procedures performed from January 1980 through June 1996. During this time, 100 consecutive patients underwent a single-vessel coronary artery bypass. All patients were men with a mean age of 59+/-9 years (range, 35 to 78 years) and a mean ejection fraction of 56+/-8% (range, 35 to 77%). The vessels bypassed included the left anterior descending in 66 (66%), right coronary artery in 31 (31%), and the obtuse marginal in 3 (3%). RESULTS: Short-term results reveal no deaths and six (6.0%) complications. Long-term follow-up by chart review and telephone survey was available in 87 (87%) patients at a mean of 46.9 months (range, 12 to 151 months). Cumulative freedom from angina and repeated revascularization was 93% and 98% at 1 year and 55% and 81% at 10 years, respectively (Kaplan-Meier). CONCLUSION: Single-vessel coronary artery bypass for isolated single-vessel disease can be performed with minimal morbidity and no mortality and provides excellent long-term relief of angina.

Adult↗

PubMed1991

Does intravenous milrinone have a direct effect on diastolic function?

Bipyridine derivatives have recently been introduced as a new class of inodilator drugs in the intravenous therapy of heart failure. A member of this class is milrinone, which improves the inotropic state and reduces ventricular afterload, leading to improved hemodynamics. Because systolic and diastolic function are intimately related, it can be expected that the diastolic muscle properties are influenced by changes in systolic function and therefore by milrinone therapy. Since end-diastolic pressure may shift as a result of a change in ventricular volume alone, a complete left ventricular diastolic pressure volume (LVDPV) relationship must always be measured before one can make firm conclusions regarding changes in diastolic function. After a LVDPV relationship is obtained, one should identify the variables that can modify this relationship without directly affecting the intrinsic diastolic muscle properties. These variables can be divided into static effects (coronary vascular bed volume, right ventricular pressure, and pericardial pressure) and dynamic effects (viscoelasticity and myocardial active relaxation). Increments in coronary perfusion pressure of perfusion flow (vascular bed volume) are known to stiffen the cardiac wall (turgor effect). Changes in right ventricular pressure or pericardial pressure are other factors affecting the LVDPV relationship by changing transmural pressure. This effect is more pronounced when the ventricle is already stiff, such as in patients with myocardial hypertrophy. Dynamic effects become important when a LVDPV relationship is measured during isolated cardiac cycles; they include viscoelasticity and abnormal myocardial relaxation. Clinical assessment of diastolic cardiac performance assumes a model in which the heart is considered an elastic body (while in fact it is viscoelastic).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiotonic Agents↗

PubMedDate not supplied

Nicotine patches in Alzheimer's disease: pilot study on learning, memory, and safety.

In view of the cholinergic deficits present in patients with Alzheimer's disease (AD), a widely investigated treatment strategy for the cognitive deficits in AD is cholinergic stimulation. Although nicotinic cholinergic receptor binding has been demonstrated to be deficient in the AD brain, the predominant theoretical and therapeutic focus to date has been on muscarinic cholinergic receptors and systems. The purpose of the present study was to evaluate the effects of sustained nicotine administration on behavior, cognition, and physiology. A double-blind placebo-controlled trial was conducted in which six patients with probable AD were exposed to 7, 8, and 7 days of placebo, nicotine, and washout, respectively. Daily sessions evaluating learning, memory, and behavior were conducted. Global cognitive functioning, rest and activity levels, cardiac activity, and blood levels were also measured. Findings included improved learning during the nicotine condition, which persisted throughout washout. Memory, behavior, and global cognition were not significantly affected. Sustained administration of nicotine appeared to be safe, although sleep showed a significant decrease.

Administration, Cutaneous↗