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Biomedical subjects

D F Barr

Publications and source records attributed to D F Barr.

5 recordsLinked to original sources
PubMed1984

Effect of dietary fiber on a guinea pig intestinal anaerobe, Bacteroides ovatus.

The purpose of this study was to determine the effect of fibrous plant components on the growth of intestinal bacteria. An anaerobe was isolated from the guinea pig cecum and identified as Bacteroides ovatus. The organism was grown anaerobically in two types of media and shown to require hemin or protoporphyrin IX. Treatment of the media with water-insoluble fractions of alfalfa, cabbage, spinach or wheat bran inhibited growth of the culture. Inhibition occurred whether the residue remained in the medium during culture growth or was removed before inoculation. A chelating resin also removed an essential component of the medium. Both treatments depleted the medium of hemin and addition of hemin restored growth and acid production. Treatment of the water-insoluble residues of alfalfa or cabbage with dilute NaOH decreased their inhibitory effects. This suggests that plant cell wall components possess unique and labile chemical properties. Dietary fiber may inhibit the growth of some anaerobic species in the lower intestinal tract by making hemin unavailable.

Animals↗
PubMed1977

Application of binaural beat phenomenon with aphasic patients.

We investigated whether six aphasics and six normal subjects could binaurally fuse two slightly differing frequencies of constant amplitude. The aphasics were subdivided into two groups: (1) two men who had had mild cerebrovascular accidents (CVAs) during the past 15 months; (2) four men who had had severe CVAs during the last 15 months. Two tones of different frequency levels but equal in intensity were presented dichotically to the subjects at 40 dB sensation level. All subjects had normal hearing at 500 Hz (0 to 25 dB). All six normal subjects and the two aphasics who had had mild CVAs could hear the binaural beats. The four aphasics who had had severe CVAs could not hear them. A 2 X 2 design resulting from this study was compared using chi2 test with Yates correction and was found to be significantly different (P less than .05). Two theories are presented to explain these findings: the "depression theory" and the "temporal time-sequencing theory." Therapeutic implications are also discussed relative to cerebral and/or brain stem involvement in the fusion of binaural stimuli.

Acoustic Stimulation↗