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Biomedical subjects

M H Williams

Publications and source records attributed to M H Williams.

At least 127 records · Page 7Linked to original sources
PubMed1978

The effect of blood infusion upon endurance capacity and ratings of perceived exertion.

The purpose of this investigation was to study the effect of blood infusion upon maximal endurance capacity and ratings of perceived exertaion (RPE). Sixteen long-distance runners, 13 of whom were marathoners, undertook four trials (T1-T4) of a treadmill run to exhaustion over a five week period. Criterion measures were time to exhaustion (TE) and RPE during each T. Data on Hb, Hct and RBCs were collected prior to each trial. Based on TE at T1, Ss were matched and assigned to either the experimental (E) or control (C) group. One week after T1, all Ss had 460 ml blood withdrawn. T2 was undertaken 2 weeks postwithdrawal. One week after T2, or 21 days postwithdrawal, the E group was infused with their own RBCs while the C group received 460 ml normal saline. T3 was taken 2 hours postinfusion and T4 one week later. The results of the factorial repeated measures ANOVA revealed no significant differences (p less than .05) between groups for either TE or RPE, even though the Hb level for the E group was significantly higher (P less than .01) than the C group at T3 and T4.

Analysis of Variance↗
PubMed1978

Apneusis.

Two cases of apneustic breathing that had several unusual features, as compared with experimental apneusis, are reported here. Both patients had intact vagal function. Respiratory rhythm showed mainly inspiratory apneusis, with a relatively smooth background rhythm. Frequency and duration of apneusis either decreased or were unaffected by breathing CO2, and increased, in one case, after hyperventilation. Both patients were alert and conscious. One had a long history of narcotic abuse, but had no other neurological or respiratory abnormality. Another had been deaf and mute since an episode of meningitis in childhood and had had apneusis for over 35 years, but suffered no other neurological abnormality. These unusual features suggest that the pathogenic mechanisms for apneusis are not the same in experimental models and patients.

Aged↗
PubMed1975

Dose response of patients with asthma to inhaled isoproterenol.

In 12 patients with asthma, inhalation of approximately 0.02 mg of isoproternol produced as much increase in peak expiratory flow rate (PEFR) as had a previous inhalation of approximately 0.16 mg of isoproternol at a time when the pre-treatment PEFRwas similar. A group or patients recorded measurements of their PEFR before and after inhalation of varying doses of isoproterenol, ranging from 0 to 0.08 mg. In each patient, only data obtained when control PEFRs were similar were utilized. A maximal effect was noted after inhalation of 0.02 mg of isoproterenol, and no further increase of PEFR was noted after inhalation of larger doses. Inhalation of 0.02 mg or less of isoproterenol produces a maximal effect on PEFR of patients with asthma.

Aerosols↗
PubMed1975

Treatment of asthma with triamcinolone acetonide aerosol.

Thirty-five steroid-dependent asthmatic patients have been treated with an aerosol of triamcinolone acetonide for periods ranging from 8 to 26 months. Fourteen patients discontinued the oral use of steroids for the first time in from 2 to 19 years and throughout the period of treatment with aerosol, have not required any other steroid medication. Fifteen patients were able to discontinue oral use of steroids but have required one or more short supplemental courses of oral steroid treatment for exacerbations of asthma. Six patients have either continued to require oral steroid therapy, or their symptoms have been incompletely controlled by the aerosol. Steroid aerosols represent an important advance for the treatment of asthma. Small doses which do not suppress adrenal function and do not produce hyperadrenocorticism make it possible for most patients to eliminate or substantially reduce their requirement for oral steroid therapy.

Administration, Oral↗
PubMed1975

Effects of post-hypnotic suggestions on muscular endurance.

This study examined the effects of post-hypnotic suggestions upon maximal endurance capacity, Borg ratings of perceived exertion, and heart rate. Experimental subjects were administered post-hypnotic suggestions to improve or decrease performance, and control subjects were given similar instructions during the awake state. Endurance time could be decreased significantly when the fatigue suggestion was given to experimental subjects, but performance could not be enhanced with the facilitating suggestion. Control subjects showed no significant changes across conditions. The Borg ratings indicated that experimental subjects experienced subjective changes as suggested by the hypnotist. In addition, analysis failed to find any significant differences for the heart-rate data.

Adult↗
PubMed1975

Cardiac response to repeated doses of isoproterenol aerosol.

We studied 18 patients with moderate to severe asthma for cardiac response to repeated doses of isoproterenol aerosol. In only 1 patient was there a significant increase in heart rate immediately after inhalation of isoproterenol aerosol, and it lasted only for 1 minute. In 2 patients increased heart rate was either due to breathholding or to the propellant in the aerosol. There was no cumulative effect on heart rate. Arrhythmias did not develop at any time despite repeated doses of aerosol every 5 to 20 minutes. Peak expiratory flow rate increased 5 minutes after the first dose, and it increased even further after repeated doses; at no time did it decrease after repeated doses.

Adolescent↗
PubMed1975

Effect of caffeine upon maximal muscular endurance of females.

The effect of various dosages of caffeine upon maximal endurance capacity in females was studied. The effect of caffeine upon resting heart rate (RHR), submaximal heart rate (SHR), maximal heart rate (MHR), and ratings of perceived exertion (RPE) was also studied. Prior to undertaking a standarized progressive workload to exhaustion on an electric bicycle ergometer, each subject consumed either a placebo, small (4 mg/kg), medium (7 mg/kg) or large (10 mg/kg) dose of caffeine. A double-blind procedure was followed. Mean times to exhaustion for the placebo, small, medium and large dosages of caffeine were, respectively, 299.5, 312.1, 299.8, and 303.2 seconds. MHR were respectively, 183.4, 185.0, 185.4, and 184.4. Maximal RPE were 16.6, 17.0, 16.3, and 17.1. The analysis of variance revealed no significant differences between the drug trials for the above three variables; in addition, no significant differences were noted for the RHR, SHR, and submaximal RPE. Within the limitations of this study, the following conclusion appears warranted: A small, moderate, or large dose of caffeine exerted no significant effect upon maximal endurance time, RHR, SHR, MHR, or RPE at either submaximal or maximal workloads.

Adaptation, Physiological↗