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Biomedical subjects

J G Logan

Publications and source records attributed to J G Logan.

18 recordsLinked to original sources
PubMed1998

Knee joint function and the energy cost of level walking in soccer players.

OBJECTIVES: To study self reported knee joint problems and the energy costs of level walking in soccer players. METHODS: Seventeen soccer players and twelve control subjects between 18 and 27 years old participated in the study. A questionnaire was used to establish the amount of participation in soccer and the frequency and extent of knee injuries. The physiological cost index (PCI) was used as an index of the energy costs of level walking. RESULTS: Soccer players had a significantly higher PCI than control subjects (p = 0.0001). Control subjects had a mean (SD) PCI of 0.23 (0.06) beats/m and soccer players had a mean PCI of 0.42 (0.12) beats/m. Some 82% of the soccer players experienced knee joint problems, whereas only 25% of the control group had problems. CONCLUSIONS: This study shows that college soccer players have a higher rate of self reported knee problems and higher energy costs of level walking than people who do not play soccer.

Adolescent↗
PubMed1982

Leucocyte sodium-potassium adenosine triphosphatase and leukemia.

Na-K ATPase of healthy leucocytes is relatively low (109 +/- 20 nmol . mg-1 . h-1), as is the permeability of the plasma membrane to cations. In this study of leucocytes from leukaemic patients, the Na-K ATPase was increased. There was an associated increase in membrane permeability to sodium and calcium. In one patient, this led to a clinically dangerous and spurious suggestion of hyperkalaemia. It is suggested that some leukaemic conditions may be associated with 'leaky' membranes.

Calcium↗
PubMed1980

The extrusion of sodium ions from presynaptic nerve endings of rat cerebral cortex.

(Na+-K+) ATPase is present in synaptosomal preparations and it is assumed to represent the sodium-potassium pump. 10 microM-noradrenaline activates (Na+-K+) ATPase approximately 100%, but 50 microM-noradrenaline does not stimulate the rate of 22Na extrusion from synaptosomes. The results suggest that it is unlikely that the noradrenaline stimulation of (Na+-K+) ATPase is part of a feedback mechanism whereby released noradrenaline can influence the activity of the presynaptic sodium pump.

Adenosine Triphosphate↗
PubMedDate not supplied

The measurement of dynamic compartment pressure during exercise.

Anterior tibial compartment pressures have been examined during exercise in nine healthy university students. Six male and three female subjects weighing 140 to 160 pounds and between 18 and 25 years of age were tested. A slit catheter was introduced into the muscle belly of the subjects' right anterior tibial compartment and dynamic compartment pressures measured using an F.M. telemetry system. Subjects were exercised on a treadmill at speeds from 1 to 6 mph and the variations in compartment pressure during one exercise cycle (one stride length) and over the course of the exercise period examined. Results have shown that both average and peak to peak pressures measured during exercise are much higher than those recorded at rest, and compartment pressures rose with increasing speed.

Adolescent↗