Biomedical subjects

W R Powers

Publications and source records attributed to W R Powers.

4 recordsLinked to original sources

PubMed2000

The Harvard study of values: mirror for postwar anthropology.

In 1949, social scientists at Harvard University began a long-range, multidisciplinary research project called the Comparative Study of Values in Five Cultures. The topic of values had been hotly debated since the 1920s, a debate that was renewed with vigor in the postwar period. When Clyde Kluckhohn, an anthropologist well known for his work among the Navajos, designed the Values Study research, he thus focused on a topic of much interest. This essay describes how this little-known project had roots in the debate on values and cut a trajectory through a quickly changing intellectual environment.

Anthropology, Cultural↗

PubMed1998

Tibiofemoral contact pressures in degenerative joint disease.

Using tibiofemoral joints from older (age, 53-80 years) human cadavers with articular cartilage degeneration, contact pressures and contact areas were measured in the extended knee in four conditions: (1) neutral alignment; (2) 5 degrees varus (simulating single limb stance of gait); (3) 5 degrees valgus; and (4) after a 5 degrees proximal tibial closing wedge valgus osteotomy. In degenerated cartilage, contact pressures were reduced at the lesion sites and were high on the borders of the lesions. No statistically significant changes occurred in contact pressures and areas when values from neutral loading were compared with values during loading in each of the other three conditions. Lateral average and maximum contact pressures were less in varus loading than in valgus loading. Equal medial and lateral contact pressures during varus loading, in contrast to lower medial than lateral contact pressures in the other three loading, supports the theory that the varus moment imposed on the knee in single limb stance could be a mechanism causing medial tibiofemoral osteoarthritis. The 5 degrees valgus osteotomy resulted in contact pressures similar to those in neutral loading. These experiments do not support the value of the 5 degrees valgus osteotomy in reducing contact pressures on the medial tibial plateau.

Aged↗

PubMed1992

Motoneuron excitability modulation after desensitization of the skin by iontophoresis of lidocaine hydrochloride.

Soleus motoneuron excitability was monitored after skin desensitization by iontophoresis of lidocaine hydrochloride in able-bodied subjects. Motoneuron excitability was measured by plotting H-reflex recovery curves before and after the application of lidocaine hydrochloride or a placebo. Significant H-reflex augmentation between 50 and 1,000 msec resulted after both iontophoretic application of the drug and the placebo (p less than .05). In addition, H-reflex initial recovery decreased by 20 to 30 msec in 75% of the subjects tested (p less than .05). H-reflex recovery curve facilitation lasted 30 minutes and returned to control values 45 minutes post-iontophoresis. H-reflex facilitation was not significantly different between the drug and the placebo treatments. It was concluded from these results that low-voltage, galvanic electric stimulation associated with iontophoresis predominantly caused the increase in motoneuron excitability, although other peripheral facilitatory factors may have been involved. Furthermore, cutaneous desensitization appeared not to have an effect on motoneuron excitability. This conclusion was based on the observation that similar H-reflex amplitude augmentation resulted after administration of a placebo as well as an active drug.

Adult↗

PubMed1981

Topical anesthesia: a possible treatment method for spasticity.

Topical anesthesia was applied to the skin of the leg and thigh of a hemiparesis patient resulting from embolic infarction in the middle cerebral artery. After application of the anesthesia, the angular displacement of the ankle and knee joints measured during a full gait cycle showed a substantial shift towards normal. This response indicated a reduction in muscle spasticity which was confirmed by clinical tests. Neurophysiologic studies performed on the patient suggested that the reduction in muscular hypertonicity was mediated by reduced cutaneous inputs on the alpha - gamma motoneuron interaction. This conjecture is supported by studies of other investigators performed on animals as well as humans.

Administration, Topical↗