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Biomedical subjects

D R Wolfe

Publications and source records attributed to D R Wolfe.

6 recordsLinked to original sources
PubMed1990

Effects of velocity of isokinetic training on strength, power, and quadriceps muscle fibre characteristics.

Twenty young men trained the right knee extensors and flexors on an isokinetic dynamometer three times weekly over a 10-week period. During each session, 10 men in the slow training group completed three sets of 8 maximal contractions at a rate of 1.05 rad s-1, whereas the other 10, the fast group, completed three sets of 20 contractions at a rate of 4.19 rad s-1. Subjects wer pre- and post-tested for peak torque and power on an isokinetic dynamometer at 1.05, 3.14, and 4.19 rad s-1. Proportions of muscle fibre-types and fibre cross-sectional areas were determined from biopsy specimens taken before and after training from the right vastus lateralis. When testing was conducted at 1.05 rad s-1, the slow group improved (P less than 0.05) peak torque by 24.5 N m (8.5%), but no change was noted for the fast group. Power increased (P less than 0.05) by 32.7 W (13.6%) in the slow group and 5.5 W (2.5%) in the fast. At 3.14 rad s-1, both groups increased (P less than 0.05) peak torque and power. At 4.19 rad s-1, the fast group increased (P less than 0.05) peak torque by 30.0 N m (19.7%), whereas no training effect was observed in the slow group. There was no significant change in power in either group at 4.19 rad s-1. No significant changes were observed over the 10-week training period in percentages of type I, IIa and IIb fibres, but both groups showed significant increases (P less than 0.05) in type I and IIa fibre areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Graded exercise testing early after myocardial revascularization surgery.

The response to early graded exercise testing (GXT) was studied in 227 patients at a mean of 15.3 days after myocardial revascularization surgery (MRS). GXT followed a modified Bruce protocol without multiples of resting energy expenditure (MET) restrictions and a target heart rate (HR) of 90% of age-predicted maximal HR. The decision as to precisely when to administer the GXT after surgery was made on an individual case basis by the cardiovascular surgeon and the attending cardiologist. For the data analysis, patients were grouped according to the number of days the GXT was administered after surgery: group 1, 7 to 14 days (n = 164); group 2, 15 to 28 days (n = 46); and group 3, greater than 28 days (n = 17). The use of beta blockers was also determined on an individual case basis by the attending cardiologist rather than on a random basis. Ninety-seven of the 227 patients were on beta blockers. Ventricular ectopic activity (VEA), ST-segment changes (STTC), peak HR, peak systolic blood pressure (SBP), peak rate-pressure product (RPP), and peak METs were assessed during exercise. No major complications occurred during testing. Approximately two thirds (67.4%) of the tests were terminated voluntarily by the patient, and 22.5% were stopped by the attending physician. Only 10.1% of the subjects reached the target HR. Chi-square analysis failed to reveal any association between time of testing after surgery and either STTC or VEA. Analysis of variance failed to reveal any effects of group or beta blocker on peak METs attained during GXT; however, patients not using beta blocker medication attained higher peak HR, SBP, and RPP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Fluorescein angiography basic science and engineering.

Fluorescein angiography is an application of the physical phenomenon of fluorescence, which is phosphorescence in which the quantum mechanical decay curve is so rapid that it appears instantaneous, and it consequently has no afterglow. Sodium fluorescein is excited by light energy between 465 and 490 nm, and it decays into a lower state emitting light energy between 520 and 530 nm as fluorescent radiation. The free electrons available for excitation are reduced by chemical bonding between the fluorescein dye and plasma proteins to which up to 80% of the dye is bound in the bloodstream, thus reducing overall fluorescence. Optimalization of the observed and recorded fluorescence is afforded by providing exciter and barrier filters with as little overlap as possible to reduce or eliminate contrast reducing pseudofluorescence.

Chemical Phenomena↗
PubMed1986

Short- and long-term prognostic value of graded exercise testing soon after myocardial infarction.

We attempted to determine whether graded exercise testing (GXT) soon after a myocardial infarction (MI) using an unlimited metabolic equivalent (MET) level and target heart rate (HR) of 90% of the age-predicted maximal HR is a safe procedure and yields prognostic results different from tests that use lower level end points. We administered GXT to a random sample of 85 patients at a mean of 14.8 days post-MI. End points that included ST-segment depression (STD), angina pectoris (AP), ventricular ectopic activity, and achieved MET level during testing were evaluated as predictors of cardiac events that include death, recurrent nonfatal MI, and coronary artery bypass graft surgery. We conducted short-term follow-up monitoring for one year after the initial MI and long-term follow-up monitoring for a mean of 864.7 days. No serious complications occurred during testing. Angina pectoris, STD accompanied by AP, and achieved MET level were predictive (p less than .05) of future fatal and nonfatal cardiac events during the first year of follow-up monitoring. Fifty-nine percent of the patients with AP suffered a subsequent cardiac event within one year, whereas only 17% of those without AP experienced another cardiac event. Sixty-seven percent of the patients with both STD and AP had a subsequent cardiac event within one year, but only 22% of those without AP and STD had a subsequent cardiac event. For the long-term follow-up monitoring, the presence of AP and a low achieved MET level during testing were associated with subsequent cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1975

Treatment of hyperparathyroidism by percutaneous embolization of a mediastinal adenoma.

Percutaneous embolization of parathyroid adenomas was attempted in three hypercalcemic patients with previously unsuccessful neck explorations. Two adenomas were in the mediastinum and the third was within the thyroid lobe. Autologous clot, Gelfoam, and silicone rubber were used to obstruct feeding arteries. The intrathyroidal adenoma failed to respond but both mediastinal adenomas were infarcted. Hyperparathyroidism recurred after 7 months in one patient but the other remains normocalcemic 8 months postembolization.

Adenoma↗