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Biomedical subjects

M H Williams

Publications and source records attributed to M H Williams.

At least 73 records · Page 4Linked to original sources
PubMed1989

Radiographic measurement of total lung capacity in acute asthma.

The thoracic cage appears to be large during attacks of asthma. Lung volume measurements by body plethysmography and helium dilution have suggested that total lung capacity may be increased during an acute attack of asthma, but doubt has been cast on the accuracy of these measurements in the presence of airflow obstruction. The change in total lung capacity has therefore been investigated during and after an acute attack of severe asthma in 32 patients by a radiographic technique. There was a small decrease (0.29 l) in mean total lung capacity between admission and follow up, though a quarter of the subjects showed a slight increase. There was no correlation between change in total lung capacity and change in expiratory flow rates, arterial carbon dioxide tension on admission, body mass index, and length of stay in hospital. Our findings agree with previous reports of a decrease in total lung capacity with improving airway obstruction, but the changes were small and inconsistent.

Acute Disease↗
PubMed1989

Vitamin supplementation and athletic performance.

Vitamins serve primarily as regulators of metabolic functions, many of which are critical to exercise performance. Depending upon the nature of their sport, e.g., strength, speed, power, endurance, or fine motor control, athletes may use megadoses of various vitamins in attempts to increase specific metabolic processes important to improved performance. Surveys have indicated that most elite athletes do take vitamin supplements, often in dosages greater than 50-100 times the United States Recommended Dietary Allowances. The theoretical basis underlying the use of each vitamin depends upon its specific metabolic function in relation to sport. Vitamin A functions to maintain night vision; thiamin, riboflavin, niacin, and pantothenic acid are all involved in muscle cell energy metabolism; niacin may also block free fatty acid release; pyridoxine is involved in the synthesis of hemoglobin and other oxygen transfer protein; folic acid and vitamin B12 are integrally involved in red blood cell (RBC) development; vitamins C and E are antioxidants, possibly preventing the destruction of the red blood cell membrane during exercise; vitamin D may be involved in muscle cell energetics through its influence on calcium. These are but a few of the possible metabolic functions of vitamins which have been suggested to have ergogenic applications to sport. Research has shown that a vitamin deficiency impairs physical performance. If this deficiency is corrected, performance usually improves. In general, vitamin supplementation to an athlete on a well-balanced diet has not been shown to improve performance. However, additional research with certain vitamins appears to be warranted, such as with the vitamin B complex and fine motor control, and with vitamin E and endurance at high altitudes. Moreover, research with megadose supplementation may also be necessary.

Efficiency↗
PubMed1989

The malpractice claims experience of physicians investigated for inappropriate prescribing.

Inappropriate prescribing of controlled substances, primarily opiates and benzodiazepines, is the most common complaint brought before the Oregon Board of Medical Examiners. We describe the malpractice claims experience of 120 physicians previously investigated by the Oregon board for inappropriate prescribing. These physicians were matched with a comparison group by age, specialty, and practice location. We found that a mean of one malpractice claim had been filed against each physician in our study, with the specialties of obstetrics and gynecology, neurosurgery, and orthopedics having the most claims. A significantly higher mean number of malpractice claims had been filed against 31 physicians disciplined by the board. Our study suggests a role for state regulatory boards in the malpractice area. We propose that such bodies do practice reviews based on the convergence of two events, a disciplinary action such as those described in this article and the filing of more than one malpractice claim against a physician. Further research is needed on inappropriate prescribing by physicians and its possible association with malpractice.

Drug Prescriptions↗
PubMed1989

Physicians investigated for inappropriate prescribing by the Oregon Board of Medical Examiners.

We retrospectively reviewed all allegations of inappropriate prescribing investigated by the Oregon Board of Medical Examiners from 1981 through 1986. Inappropriate prescription writing accounted for 51% of all investigations during this period, with controlled drugs, primarily opiates and benzodiazepines, accounting for most complaints. Of 130 physicians investigated, more than half had previous complaints; 50 were ultimately restricted or disciplined by the board. Inappropriate prescribing of controlled drugs is probably underdetected and frequently repeated. Available literature suggests that inappropriate prescribing of other drugs, especially antibiotics, is extremely common, but such problems were rarely identified by the current discovery and review processes of the Oregon board. Inappropriate prescribing will require increased attention from physician educators and licensing boards.

Adult↗
PubMed1988

Evidence of a novel association of unsaturated fatty acids with Gc (vitamin D-binding protein).

The strong sequence homology described recently between Gc (Vitamin D-binding protein) and albumin, and the ability of the latter, to bind 2-p-toluidinylnaphthylene sulfonate (TNS) promoted similar binding studies with Gc. TNS bound to native Gc as demonstrated by fluorescence, but chloroform:methanol extraction of Gc and gas chromatography revealed that large amounts of unsaturated fatty acids - 16:1, 18:1, 18:2 and 20:4 were also associated with Gc. In addition, TNS fluorescence was abolished by delipidation of Gc, and restored upon subsequent reconstitution with fatty acid. Finally, 70-80% of [3H]-arachidonic acid added to whole serum bound to Gc. These results demonstrated that TNS fluorescence of the native molecule reflects associated lipid, and suggest a novel role for Gc as a reservoir for a circulating pool of unsaturated fatty acids.

Animals↗
PubMed1988

Design and application of an expert system for mobile phase optimisation in reversed-phase liquid chromatography.

The selection of the optimum composition for the mobile phase in reversed-phase high-performance liquid chromatography (HPLC) is a complex task; conventional approaches require the expenditure of significant amounts of time by the analyst, particularly for complex mixtures of solutes of biological origin. Some of the existing strategies for the automated optimisation of mobile phase composition (e.g. Simplex), may fail if the elution order of the components changes; or they may require that standards be chromatographed in order to establish the retention behaviour of each component in a mixture (e.g. resolution mapping). These problems may be overcome if the retention behaviour of each individual solute can be established from the chromatogram of the mixture. In this regard, components can be tracked by exploiting the spectral information generated by a rapid scanning photodiode array detector. Unfortunately this information is often insufficiently detailed to allow an unambiguous model of retention behaviour to be constructed. The system developed by the Authors uses these spectral data as a basis for constructing one or more hypothetical retention models, each of which is refined or rejected as further information is obtained during the progress of the experiment. To improve the reliability of the retention models proposed by the system, the spectral data are utilised in a number of tests designed to assess the purity of each chromatographic peak. The information so generated may be used in conjunction with any previously acquired spectral data both to select an appropriate method for extracting spectra for each component from the matrix of (A, lambda, t) data and to establish reliability parameters for the resultant spectra. The development and philosophy of the expert system developed for eluent optimisation in reversed-phase HPLC is discussed.

Journal Article↗
PubMed1988

Role of group-specific component (vitamin D binding protein) in clearance of actin from the circulation in the rabbit.

The possible role of group specific component (Gc) (vitamin D-binding protein) in the clearance of cellular actin entering the circulation was examined with 125I-labeled Gc and actin injected into a rabbit model. Although filamentous F-actin is depolymerized primarily by plasma gelsolin, greater than or equal to 90% 125I-actin injected in either monomeric G- or F-form became complexed eventually with Gc (1:1 molar ratio). Clearance of Gc complexes was much faster (greater than 90% within 5 h) than that of native Gc (t1/2 = 17.2 h). Nephrectomy did not significantly alter the clearance of either Gc or actin. Since Gc complexes are dramatically increased in situations of tissue necrosis such as in fulminant hepatic failure, the current results suggest a crucial role for Gc in sequestration and clearance of released cellular actin.

Actins↗
PubMed1988

Drug treatment refusal and length of hospitalization of insanity acquittees.

Thirty-three insanity acquittees who had refused drug treatment were matched to a sample of nonrefusing hospitalized insanity acquittees in an attempt to measure the effect of treatment refusal on length of hospital stay. No measurable effects on the length of hospitalization were found. However, upon comparing the amount of time under court jurisdiction spent in the hospital and on conditional release in the community, it becomes evident that refusers spent significantly greater proportions of time hospitalized than the average hospitalized insanity acquittee, who had less hospitalization and spent more time on conditional release. These differences do not seem to be related to the issue of treatment refusal.

Adult↗
PubMed1988

The influence of the right to refuse treatment on precommitment patients.

The unplanned extension of the right to refuse treatment to the precommitment period is described in this paper. This extension of the right to refuse treatment has important public policy implications for the civil commitment process. These implications, as well as the pros and cons of the extension of the right to refuse treatment, are discussed.

Adult↗
PubMed1987

Altered conformation of Gc (vitamin D-binding protein) upon complexing with cellular actin.

Complexing of serum Gc (Vitamin D-binding protein) with cellular actin can occur in the extracellular space as a result of cell turnover, and particularly cell necrosis. The clearance of such complexes is significantly more rapid than that of Gc alone, and several tissues are involved in their uptake, but the mechanisms involved are unknown. We present evidence here that interaction with actin results in alteration of certain physicochemical properties of Gc. Fluorescence of the hydrophobic probe 2-p-toluidinylnaphthylene-6-sulfonate was abolished by complex formation with actin. In addition, isoelectric focusing of complexes between Gc, and actin from different tissues, revealed that complexes were generally more acidic than either protein individually. These findings indicate that complexing of Gc with actin results in altered conformation.

Actins↗
PubMed1987

Cough and wheezing from beclomethasone aerosol.

Cough and wheezing are frequent side effects of inhaling beclomethasone dipropionate aerosol (BA) in patients with asthma. Twenty percent of our outpatient asthmatic subjects are unable to take BA due to these side effects. Twelve patients with history of severe cough and wheezing after inhaling BA were tested. Three puffs of either BA or placebo (Plc) were administered from a metered dose inhaler (MDI) in a double-blind crossover design. They coughed a mean of 31 times after BA and 19 times after Plc. Forced expiratory volume in one sec (FEV1) declined a mean of 22.6 percent after BA and 22.0 percent after Plc. Pretreatment with albuterol attenuated both the cough and the drop in FEV1. Follow-up study showed that regular pretreatment with bronchodilator enabled seven of 12 patients to tolerate BA therapy. The remaining five required a short course of increased dose oral steroid therapy. Cough and wheezing are frequent side effects of BA therapy that interfere with regular compliance. Pretreatment with a bronchodilator is effective in attenuating these side effects in some patients; in others, a short course of oral steroid therapy may be necessary.

Aerosols↗
PubMed1987

Lack of effect of hydration on sputum production in chronic bronchitis.

Patients with chronic lung disease productive of sputum are generally encouraged to drink a large amount of fluid to facilitate sputum production. This clinical practice has not been tested systematically. Twelve outpatients with chronic obstructive pulmonary disease in clinically stable condition who had daily sputum production were asked in random sequence: 1) to drink one glass of fluid every waking hour after supper and upon waking the next morning (hydration), 2) to drink no fluid after supper and upon waking the next morning (dry), and 3) to drink fluid ad lib (ad lib). Each morning sputum collection was started upon waking and continued for four hours. The differences in volume, elasticity of sputum, respiratory symptoms, and ease of expectoration were not significant. We conclude that moderate hydration and dehydration have no effect on volume expectorated, the elasticity of sputum, respiratory symptoms or forced expiratory volume in one second.

Aged↗
PubMed1987

Cough and wheezing from beclomethasone dipropionate aerosol are absent after triamcinolone acetonide.

STUDY OBJECTIVE: To test the hypothesis that patients with asthma who develop cough and wheezing after the use of beclomethasone aerosol would have a better tolerance for triamcinolone aerosol. DESIGN: Randomized, double-blinded, crossover trial. SETTING: Pulmonary function laboratory. PATIENTS: Volunteer sample of 24 patients attending an asthma clinic who had developed cough, with or without wheezing, after inhaling beclomethasone aerosol. All patients completed the study. INTERVENTIONS: Aerosols were used in habitual manufacturers' preparations and canisters, but both were administered in three puffs through the delivery system used for triamcinolone. The preparations differed in drug (beclomethasone dipropionate or triamcinolone acetonide), propellant (trichloromonofluoromethane and dichlorodifluoromethane, or dichlorodifluoromethane alone, respectively) and dispersant (oleic acid or dehydrated alcohol, respectively). PATIENTS inhaled three puffs of one aerosol on one day and three of the other on the next. MEASUREMENTS AND MAIN RESULTS: Forced expiratory volume in one second (FEV1) was measured before and after each aerosol application. The FEV1 decreased a mean of 17.7% from baseline after inhalation of beclomethasone, and 0.8% after triamcinolone (difference, 16.9; 95% confidence limits, 12.36 to 21.34; p less than 0.001). Coughs were counted after each puff. The mean number of coughs after beclomethasone aerosol inhalation was 35.8, and after triamcinolone, 0.5 (difference, 35.3; 95% confidence limits, 22.62 to 47.98, p less than 0.001). CONCLUSIONS: Asthmatic patients who are unable to inhale beclomethasone aerosol due to cough or wheezing can inhale triamcinolone aerosol without difficulty. Our investigation does not determine the exact cause of the coughing and wheezing with the beclomethasone aerosol, but we suspect the dispersant as the source.

Adult↗
PubMed1986

Effect of odors in asthma.

Many patients complain that some odors worsen their asthma. Perfume and cologne are two of the most frequently mentioned offenders. Four patients with a history of worsening of asthma on exposure to cologne underwent challenge with a cologne, and their pulmonary function was tested before, during, and after the exposure. Forced expiratory volume in one second declined 18 to 58 percent below the baseline period during the 10-minute exposure and gradually increased in the next 20 minutes. Saline placebo pretreatment did not affect the response to subsequent challenge. Single-blind pretreatment with metaproterenol and atropine prevented decline in one-second forced expiratory volume in three of four patients and blunted the response in the other. Cromolyn sodium prevented decline in one of four, and occlusion of nostrils prevented decline in one of three. A survey of 60 asthmatic patients revealed a history of respiratory symptoms in 57 on exposure to one or more common odors. Odors are an important cause of worsening of asthma.

Adult↗