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Biomedical subjects

L R Williams

Publications and source records attributed to L R Williams.

At least 145 records · Page 8Linked to original sources
PubMed1979

beta-Adrenergic blocking action of halonitrophenethanolamines.

A series of phenethanolamines with N-isopropyl and N-tertbutyl substituents and ring-substituted with nitro- and halogen groups has been prepared. Using guinea-pig isolated atrial and tracheal preparations, the influence of the nitro-group on the beta 1- and beta 2-antagonist actions of the mono-halogen compounds was determined, and the antagonist and partial agonist effects of the halo-nitro-compounds on beta-adrenoceptors in these tissues measured to help elucidate structure-activity relations in this series. The halonitro compounds did not show enhanced activity compared with the mono-halogen substituted analogues. Several of the new compounds showed slight but significant beta 2-antagonist selectivity of action, and one compound was significantly beta 1-selective.

2-Hydroxyphenethylamine↗
PubMed1978

Vitamin A serum and dietary vitamin A intake in lung cancer patients.

Clinical and experimental evidence indicates a possible role for vitamin A deficiency in the pathogenesis of bronchogenic carcinoma. We, therefore, measured serum vitamin A levels in 67 newly diagnosed non-resectable lung cancer patients. In 43 of these patients daily vitamin A intake was also determined. Serum vitamin A levels were within the normal range of the general population of 66 of the 67 patients. Eighteen of 43 patients had daily vitamin A intakes less than 5000 IU/day while 25 patients had daily intake above this level. The serum vitamin A level did not correlate with histologic subtype, extent of disease or presence or absence of hepatic metastases. While these data suggest that vitamin A deficiency was not implicated in pulmonary carcinogenesis, more definitive conclusions await prospective evaluation of high risk individuals followed serially for many years.

Adult↗
PubMed1978

2-Methoxyphenylethanolamines, potential beta-adrenergic blocking agents.

The effect of the introduction of a 2-methoxy substituent on the beta-adrenergic antagonistic properties of a series of 3- and 4-substituted phenylethanolamines (1) was studied. Both the series of bromo- and methyl-substituted compounds behaved similarly, indicating that electronic forces are not significant in determining beta-adrenergic antagonist activity. When compared with the corresponding phenylethanolamines without a 2-methoxy substitutent, the 2-methoxy-4-substituted derivatives (3a and 3d) had enhanced potency and selectivity but the 2,3- (3b and 3e) and the 2,5-disubstitution patterns (3c and 3f) showed a loss of activity. The inconsistent changes in activity prevented any firm conclusions being made about the effect of the ether oxygen and the beta-adrenoceptor antagonistic activity of phenoxypropanolamines.

Adrenergic beta-Antagonists↗
PubMed1978

Altered taste thresholds in lung cancer.

Taste threshold levels for the four basic taste modalities were determined in 30 male lung cancer subjects and 30 male control subjects who had no history of malignant disease. Lung cancer patients demonstrated significant alteration in taste recognition for sour but not for bitter, sweet, or salt. There were, however, quantitative differences between cancer patients and control subjects in recognition thresholds for the sweet taste modality. Some of the lung cancer subjects had demonstrated greater sensitivity to the taste of bitter than the control subjects and others were less sensitive. These alterations may account in part for the reduction of intake and for the aviodance of certain food items by lung cancer subjects. Dietary histories should be taken on all cancer patients in order to individualize dietary management, thereby improving the nutritional intake.

Adult↗
PubMed1978

Transcendental meditation and mirror-tracing skill.

Learning, performance and patterns of inter- and intra-individual variability of 32 experienced Transcendental Meditators were compared to those of 32 non-meditators. The data indicated that certain effects attributed to the practice of Transcendental Meditation (such as increased alertness and maintenance of attention, greater consistency and less anxiety) are not manifested in terms of learning and performance of a novel perceptual-motor skill.

Adult↗
PubMed1977

The beta-adrenergic activity of some monosubstituted phenethanolamines.

A series of monosubstituted phenethanolamines with N-isopropyl and N-tert-butyl substituents has been prepared. A detailed pharmacological study has been made of the beta-adrenergic activity of these materials as the nitrogen substituent and the nature and position of the phenyl substituent were changed, and their selectivity has been determined for beta1- and beta2-adrenoceptors in guinea-pig and cat tissues.

Animals↗
PubMed1977

The psychobiological model and multiple discriminant function analysis of high-calibre oarsmen.

Candidates for New Zealand rowing teams (N = 181) were given a battery of physiological, performance, anthropometric and psychological tests in order to test the psychobiological model for prediction of athletic success. A series of stepwise multiple discriminant function analyses were conducted on both separate sub-sets of variables and their combinations. The expectation that the model would not differentiate between the three age categories of oarsmen (Juniors, Colt and Senior) except for age-related factors was upheld. A more specific test of the model was an examination of the accuracy of discrimination within each age group between those who were selected for New Zealand teams and those who were not selected. The results indicated that such differentiation was best when the biological and psychological variables were used in concert. The major discriminators between selected and nonselected oarsmen on the psychobiological functions were certain anthropometric and psychological variables. Further support for the notion of the existence of a rowing stereotype was provided by testing the Senior discriminant function on the other two groups. It was concluded that the results were in accordance with the multidisciplinary psychobiological model.

Adolescent↗
PubMed1976

Specificity of training for motor skill under physical fatigue.

The purpose of the present study was to test the specificity of training principle from exercise physiology in the context of motor skill acquisition. Thirty-six college females were randomly assigned to either an experimental or a control group and both groups received 54 practice trials on a ladder climb task over four consecutive days (3,18,18 and 15 trials/day, respectively). The control group practiced under conditions of heavy interpolated fatigue on the first 3 days with day 3 representing the heavy-fatigue criterion conditions, while the experimental group did the same except for day 2 when a vowel-cancelling task was substituted for the fatigue task. On day 4 both groups practiced under the second criterion of non-fatigue conditions. Fatigue was induced by a step-up task so that a minimum HR of 180 beats/min was attained prior to each ladder trial. The results supported the specificity hypothesis that practicing a gross motor task under conditions of heavy-fatigue would facilitate performance of that task under criterion heavy-fatigue conditions. For the second criterion of non-fatigue practice, the data appeared to support the specificity principle but the rigorous test of the differences did not reach statistical significance. The overall evidence supports the position that regards heavy physical fatigue as a variable that can cause changes in the nature of certain motor skills so that the specificity of training principle becomes applicable.

Adult↗
PubMed1976

Transcendental Meditation and fine perceptual-motor skill.

30 college male meditators had a 20-min. meditation followed by a 6-min. waking phase prior to 5-min. continuous practice on the pursuit rotor task. This was followed by a 4-min. rest then a further 2-min. of pursuit rotor practice. A similar group of college males who were non-meditators (N = 30) followed the same procedures except that instead of meditating they sat quietly for the initial 20-min. period. The expectations that Transcendental Meditation would (a) facilitate learning and performance; (b) cause less within-subject variability; and (C) cause less reactive inhibition, (c) cause less reactive inhinition, were not upheld by the results. With the exception of performance, which was significantly lower for the meditators, the two groups were no different. Thus, it appears that certain reported physiological and psychological benefits that are attributed to the practice of Transcendental Meditation (such as less anxiety, greater consistency, more awareness, altertness, and attention) are not manifested in the present behavioral test of perceptural-motor function. In fact, in terms of performance, the meditators seemed to be at a disadvantage.

Adolescent↗
PubMed1976

Effects of transcendental meditation on fine motor skill.

46 college female volunteers were given 66 10-sec. trials on the pursuit rotor task in 3 practice sessions (18, 30, and 18 trials/sessions). After the first 18 trials, the 23 subjects who were practiced Transcendental Meditators mediated for a 20-min. period followed by a 5-min. "waking" phase prior to the performance of a further 30 trials on the rotor. A 4-min. rest was taken before resuming practice for the final 18 trials. The other 23 subjects, who were not meditators, followed the same procedures except instead of mediating they sat quietly with closed eyes. In terms of performance, learning, reminiscence and intra-individual variability, the two groups were similar. These results were not in accordance with the expectations that these parameters would reflect the facilitative effects of Transcendental Meditation on alertness, awareness, consistency, and resistance to stress. After the meditation session, inter-individual variability was increased for the mediation group. While the conclusion that the practice of Transcendental Meditation does not benefit acquisition of fine perceptual-motor skill appears strong, further investigation would assist in obtaining a more complete understanding of such effects on perceptual-motor behavior.

Female↗