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Biomedical subjects

F B Underwood

Publications and source records attributed to F B Underwood.

8 recordsLinked to original sources
PubMed1999

Test-retest reliability of the ulnar F-wave minimum latency in normal adults.

BACKGROUND AND PURPOSE: The purpose of this study was to measure the test-retest reliability of the ulnar F-wave minimum latency (Fmin) in normal adults. A reliable Fmin measure allows clinicians to ascribe changes in latency to true changes in a subject and not merely random daily variation. SUBJECTS AND METHODS: Fmin in the Abductor Digiti Minimi muscle was measured bilaterally in 49 healthy adults (n = 98) with a three day separation between tests. RESULTS: The Fmin reliability estimate as measured by intraclass correlation coefficient (3,1) was 0.59 with a standard error of measurement (SEM) of 1.3 msec. A paired t-test showed no significant difference (t = 1.7, df = 97, p > 0.05) between the mean scores from the two testing sessions. DISCUSSION AND CONCLUSIONS: We found moderate reliability and relatively low precision (high SEM) in Fmin scores taken from healthy individuals on two separate days. Strict adherence to our protocol and an acceptable overall precision of measurements (as measured by mean scores) suggest the contributions of rater and instrument error were low in our study. We conclude that 1) valid clinical interpretation of minimum F-wave latency findings is questionable because the Fmin measurement appears to have only moderate reliability, and 2) the lability of the phenomenon itself is the most likely contributor to variability in the Fmin latencies. Further research is warranted before electrophysiologists may be justified in attributing small changes in the Fmin to actual changes in the subject.

Action Potentials↗
PubMed1998

Effect of semi-rigid lumbosacral orthosis use on oxygen consumption during repetitive stoop and squat lifting.

The use of back belts in industry has increased despite the lack of scientific evidence supporting their efficacy. The purpose of this study was to investigate the effect of a semi-rigid lumbosacral orthosis (SRLSO) on oxygen consumption during 6-min submaximal repetitive lifting bouts of 10 kg at a lifting frequency of 20 repetitions min-1. Fifteen healthy subjects (13 men, two women) participated in this study. Each subject performed squat and stoop lifting with and without an SRLSO for a total of four lifting bouts. Lifting bouts were performed in random order. Oxygen consumption during the final minute of each lifting bout was used for analysis. A two-way analysis of variance with repeated measures was used to analyse the effects of lift and belt conditions. The stoop and squat methods were significantly different, with the squat lift requiring 23% more oxygen on average than the stoop lift for equal bouts of work. No significant difference was found between the belt and no belt condition within the same lifting technique and no interaction was present. These data suggest that an SRLSO does not passively assist the paravertebral muscles (PVM) in stabilizing the spine during submaximal lifting bouts.

Adult↗
PubMed1995

The role of Army physical therapists as nonphysician health care providers who prescribe certain medications: observations and experiences.

For two decades, Army physical therapists have been granted limited privileges to prescribe certain medications when serving as nonphysician health care providers for the primary evaluation and treatment of patients with neuromusculoskeletal dysfunctions. A brief summary of the events that led to this physician-extender role is presented. This article describes the Army regulations, credentialing process, and expanded clinical privileges developed to prepare and support physical therapists working as primary neuromusculoskeletal screeners who are credentialed to order certain pharmacologic medications. A historical synopsis of Army physical therapists ordering pharmacologic medications. A historical synopsis of Army physical therapists ordering pharmacologic medications in their expanded role as nonphysician health care providers is also presented. Results of a 1994 Army-wide survey of physical therapy clinics are provided in terms of medications prescribed and observations by those involved. The educational opportunities designed to ensure safe and appropriate uses of these privileges are described.

Drug Prescriptions↗
PubMed1994

Altered control of calcium in coronary smooth muscle cells by exercise training.

The increase in myoplasmic free Ca (Cam) is a primary trigger of contraction in vascular smooth muscle. We review data showing that the sarcoplasmic reticulum (SR) can buffer (attenuate) increases in Cam by: 1) sequestering a fraction of Ca entering the cell via sarcolemmal influx pathways, and 2) slowly releasing Ca from the SR toward the sarcolemma for extrusion from the cell, thereby decreasing subsequent agonist-induced Cam transients and contraction--so called "SR Ca unloading." Endurance exercise trained (EX), not sedentary (SED), Yucatan miniature pigs show SR Ca unloading via a ryanodine-sensitive SR Ca release pathway. The slow release of Ca from SR of EX cells may allow for efflux from the cell by close functional association with sarcolemmal Ca efflux mechanisms. In contrast, rapid, bolus release and resequestration of Ca by the SR of SED cells prevents Ca efflux from the cell. The endothelin-sensitive SR Ca store, a subset of the caffeine- and ryanodine-sensitive SR, is decreased in EX cells. Mildly increased resting Cam in EX cells may reflect a constant leak of Ca from the SR. The endothelin-sensitive SR Ca store was loaded above basal levels by depolarization-induced Ca influx. Collectively, these data indicate altered Cam regulation by the SR in coronary artery of EX animals. Future studies should focus on the molecular mechanisms of altered Cam regulation.

Animals↗
PubMed1988

Effects of inversion on cardiovascular function: the bat scan.

This study was performed to measure the effect on cardiovascular functional parameters of remaining in an inverted position for a relatively short period of time. With the aid of radionuclide gated bloodpool scanning techniques, left ventricular ejection fraction (LVEF), heart rate (HR), systolic blood pressure (SBP), systolic average rate of left ventricular emptying (dV/dt), and double product (DP) measurement values were obtained from 16 normal, healthy subjects in four positions: supine, standing, half-inverted, and fully inverted. When comparing full-inversion to supine values, the HR and double product were not significantly different, the SBP was significantly higher, and the LVEF and dV/dt values were significantly lower. There were no significant differences between the partial and fully inverted positions. Comparison of standing to fully inverted positions reveals no significant change in SBP or double product. HR, LVEF, and dV/dt values were significantly lower in inverted subjects. It is suggested that these findings reflect the mechanism by which the cardiovascular system compensates for increased ventricular end-diastolic volume. Suggestions for future investigations include inverted cardiac ultrasound and right ventricular function studies.

Adult↗
PubMedDate not supplied

The effect of stimulatory electrode placement on F-wave latency measurements.

BACKGROUND AND PURPOSE: The purpose of this study was to compare the effects of two commonly used stimulating electrode placements on F-wave latency. SUBJECTS: Fifty healthy subjects aged 20 to 47 years were tested. METHODS: F-waves were obtained from median and ulnar nerves bilaterally. A total of 200 nerves were tested. RESULTS: A paired t-test indicated a statistically significant difference in F-wave latency between the two stimulating electrode placements. Stepwise linear regression equations demonstrated that our results were consistent with previously published studies. CONCLUSION AND DISCUSSION: Although a statistically significant difference exists between the two techniques, the magnitude of the difference is not likely to be clinically important. Therefore, the most important factor may be to use a consistent technique when investigating potential neuropathies.

Adult↗