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Biomedical subjects

C R Beasley

Publications and source records attributed to C R Beasley.

14 recordsLinked to original sources
PubMed2003

Humidified nasal continuous positive airway pressure in obstructive sleep apnoea.

Heated humidification of nasal continuous positive airway pressure (nCPAP) reduces upper airway symptoms and improves initial use in obstructive sleep apnoea syndrome (OSAS). The present study aimed to assess the effect of heated humidification of nCPAP on upper airway symptoms and initial use in obstructive sleep apnoea. This study was of a randomised, crossover design. Subjects with polysomnographically confirmed OSAS were randomised to 3 weeks nCPAP treatment with heated humidification (nCPAP-humid) or placebo humidification (nCPAP pl-humid). Objective and subjective nCPAP use, upper airway symptoms, and treatment satisfaction were compared. Thirty seven of 42 patients completed the protocol. nCPAP-humid reduced the frequency of adverse upper airway symptoms. nCPAP use over 3 weeks was greater with nCPAP-humid compared with nCPAP pl-humid. No difference was found between the treatment arms in terms of subjective treatment satisfaction or alertness. Heated humidification of nasal continuous positive airway pressure reduces upper airway symptoms and is associated with a small increase in initial use but not subjective sleepiness or treatment satisfaction. The results support the use of heated humidification as a strategy to reduce side-effects related to continuous positive airway pressure but not routine initial use.

Adult↗
PubMed1990

Mucosal inflammation in asthma.

Over the past decade, it has become increasingly recognized that airways inflammation is one of the major components of asthma. Until recently, measurements of bronchial responsiveness and mediators of allergic reactions were the only methods of studying pathogenetic mechanisms in asthma. With improved diagnostic procedures such as fiberoptic bronchoscopy, it has become possible to investigate these mechanisms and the resulting inflammatory changes in situ. BAL has highlighted the presence of mast cells and eosinophils and has given proof of their mediator participation in airways inflammation and hyperresponsiveness. Endobronchial biopsies have so far yielded results that are similar to those obtained from postmortem studies, although it appears that there are varying degrees of inflammation in living asthmatics. Even in mild disease, the histopathologic features of bronchial asthma are consistent with chronic inflammation. Indirect evidence obtained from allergen challenge leading to increased bronchial hyperresponsiveness during LAR, and direct evidence of inflammatory cells and their mediators in the airway mucosa and lumen after allergen challenge argue for an active role of cells in bringing about inflammatory changes. At present, however, it is not possible to relate precisely the findings obtained by bronchoscopy to the clinical presentation and progression of asthma. Cell activation with production of potent mediators of inflammation may be more relevant to inflammation than the simple presence of these cells in the airways. Almost all the inflammatory cells present in the bronchial wall and lumen have been implicated in the pathogenesis of mucosal inflammation in asthma, but with our current state of knowledge, none can be singled out as the most important contributor. The mast cell was the first to be investigated in depth, and despite the accumulation of large amounts of data concerning its ultrastructure and function, it remains uncertain to what extent this cell is involved in inflammatory responses. Thus, while its main role appears to be that of initiator of allergen-induced responses, the eosinophil has attracted more attention as a proinflammatory cell rather than as an antiinflammatory cell with a capacity to be selectively recruited from the circulation in response to IgE-dependent signals. The eosinophil secretes potent mediators that cause damage to the bronchial epithelium and lead to bronchoconstriction. The role of other cells is at present not as well defined.(ABSTRACT TRUNCATED AT 400 WORDS)

Asthma↗
PubMed1988

Relative efficacy of oral verapamil and digoxin alone and in combination for the treatment of patients with chronic atrial fibrillation.

1. The efficacy of verapamil alone, or in combination with digoxin, was compared with digoxin alone in eight patients with chronic atrial fibrillation in this double-blind placebo-controlled study. 2. After 2 weeks on each treatment regimen, heart rate at rest and during progressive load treadmill exercise, left ventricular function at rest and nocturnal heart rate were measured. 3. Oral verapamil alone at a dose of 80 mg three times daily, or 40 mg of verapamil three times daily in combination with 0.25 mg of digoxin daily, was superior to digoxin alone in doses associated with high serum digoxin concentrations (mean +/- SEM 1.6 +/- 0.3 micrograms/l). This superiority manifested as greater control of heart rate during work rates equivalent to regular daily activities, and was not associated with deterioration in left ventricular function or worsening nocturnal bradycardia. 4. We conclude that the treatment of choice in patients with chronic atrial fibrillation is either 80 mg of verapamil three times daily or 40 mg of verapamil three times daily in combination with digoxin.

Aged↗
PubMed1987

Laser Doppler flowmetry for determining changes in cutaneous blood flow following intradermal injection of histamine.

The use of laser Doppler flowmetry (LDF) in determining changes in cutaneous blood flow following intradermal injection of histamine has been investigated in this double-blind study. In eight subjects blood flow (LDF) and weal-and-flare area (planimetry) were measured at regular intervals for 1 hr following 50-microliter injections of different concentrations of histamine (6.5 X 10(-5)-6.5 X 10(-3)M) and saline. The mean maximum increase in LDF values over the flare was at least nine-fold greater than the baseline values for all three concentrations of histamine injected. When the LDF values observed at different sites were integrated to obtain the 'LDF response' it was possible to demonstrate concentration-related increases in blood flow and to differentiate clearly between the different concentrations of histamine and saline for up to 30 min after injection. During this period, the repeatability and the time course of the LDF response was comparable with that of the flare area. These studies suggest that the noninvasive technique of LDF is a sensitive and reproducible method for quantifying the changes in cutaneous blood flow that occurs for the first 30 min after intradermal injection of histamine.

Administration, Cutaneous↗
PubMed1987

9 alpha,11 beta-prostaglandin F2, a novel metabolite of prostaglandin D2 is a potent contractile agonist of human and guinea pig airways.

Prostaglandin (PG) D2, the predominant prostanoid released from activated mast cells in humans is initially metabolized by reduction of the C-11 keto function to yield 9 alpha,11 beta-PGF2. In this study the airways effects of 9 alpha,11 beta-PGF2 were compared with those of its epimer 9 alpha,11 alpha-PGF2 (PGF2 alpha) and PGD2. 9 alpha,11 beta-PGF2 was a potent contractile agonist of isolated guinea pig trachea and 4-mm human airways in vitro; the potencies of the PGs relative to PGD2 (= 1.00) being 0.65 (NS) and 4.08 (P less than 0.001) for 9 alpha,11 beta-PGF2, and 0.52 (P less than 0.01) and 2.40 (P less than 0.001) for PGF2 alpha, respectively. When inhaled by asthmatic subjects, 9 alpha,11 beta-PGF2 was a potent bronchoconstrictor agent, being approximately equipotent with PGD2 and 28-32 times more potent than histamine (P less than 0.01). These studies suggest that 9 alpha,11 beta-PGF2 is at least equipotent with PGD2 as a bronchoconstrictor agonist, and in being a major metabolite of PGD2, could contribute to the bronchoconstrictor effect of this mast cell-derived mediator in asthma.

Adult↗
PubMed1986

Pulmonary function in chronic renal failure patients managed by continuous ambulatory peritoneal dialysis.

The influence of intraperitoneal fluid on pulmonary function was studied in 20 unselected continuous ambulatory peritoneal dialysis (CAPD) patients, all but one of whom had at least one cardiorespiratory disorder. Measurements of pulmonary function were made with the abdomen empty and following the instillation of 2 1 of dialysis fluid (full). Functional residual capacity fell with the peritoneal cavity full, due to decreases in residual volume, and expiratory reserve volume, but there was a corresponding increase in inspiratory capacity. The vital capacity remained unchanged and the total lung capacity fell only slightly. The FEV1, diffusing capacity, and distribution of ventilation were unaltered. These findings can be attributed to an increase in intra-abdominal pressure resulting in elevation of the diaphragm and increased diaphragmatic contractility. We conclude that the instillation of 21 of dialysis fluid in CAPD patients with cardiorespiratory disease does not result in a clinically significant deterioration in these aspects of pulmonary function.

Adult↗
PubMed1986

Exercise capacity in chronic renal failure patients managed by continuous ambulatory peritoneal dialysis.

Exercise capacity is documented to be poor in patients with end stage renal failure undergoing regular hemodialysis, but there is little information about exercise capacity in patients on continuous ambulatory peritoneal dialysis (CAPD). We studied a group of 18 patients undergoing CAPD, with a variety of cardiorespiratory disorders, using a progressive load treadmill exercise test. The influence of intraperitoneal fluid on work capacity was also assessed. The mean maximum oxygen uptake (VO2max) of the CAPD patients was reduced considerably (14.6 ml kg-1 min-1) compared with matched control subjects (33.6 ml kg-1 min-1). This corresponded to the difficulty experienced by these patients in carrying out daily activities. There was no significant change in VO2max or in maximum heart rate with the peritoneal cavity full. We conclude that physical fitness is poor in CAPD patients and that the infusion of dialysis fluid into the peritoneal cavity does not affect physical work capacity further.

Adult↗
PubMed1985

Pear shaped spacer nebuhaler compared with nebulised solution for terbutaline administration in acute severe asthma.

The efficacy of terbutaline (1 mg) administered from pressurised aerosol through a nebuhaler was compared in a crossover trial with terbutaline (4 mg) as nebulised solution in 20 patients with acute severe asthma. The improvements following the nebuhaler, which did not require an electrical or pressure source, were worthwhile. In contrast to earlier experience in stable asthma, the increases in FEV1 (p = 0.04) and VC (p = 0.05) at 20 minutes were greater following the higher dose as nebuliser solution than following nebuhaler use. Nebuhaler technique requires individual attention since some patients with the severe asthma breathed out through the nebuhaler reservoir due to failure to close the one-way valve.

Acute Disease↗
PubMed1985

Treatment of pneumonia with imipenem/cilastatin.

This pilot study assessed the efficacy, safety and tolerance of intravenously administered imipenem/cilastatin in the treatment of adults hospitalised with community acquired pneumonia. Thirteen patients were treated with 500 mg imipenem and 500 mg cilastatin eight hourly for a minimum of five days. Eleven patients (85%) had a clinical cure; (Legionella pneumophila was the pathogen in four, Streptococcus pneumoniae in one, Branhamella catarrhalis in one, no pathogen identified in five). One patient had a partial response (Staphylococcus aureus); and one patient was a treatment failure (Haemophilus influenzae and Klebsiella ozaenae). Clinical and laboratory side effects were mild, reversible and did not require treatment to be stopped. We conclude that the combination of imipenem and cilastatin was effective as a single agent in the treatment of the majority of these patients with hospital referred community acquired pneumonia.

Adult↗
PubMed1985

Comparison of blood gas and pH values obtained from arteriovenous fistulae and femoral arteries in chronic renal failure patients managed by hemodialysis.

The validity of obtaining blood directly from arteriovenous (a-v) fistula for blood gas and pH measurements in patients undergoing hemodialysis was examined. In such patients, blood samples were taken simultaneously from both the arterial and venous lines within the a-v fistula and from a femoral artery. We conclude that for clinical application sampling from either the arterial or venous line within an a-v fistula cannot be used for accurate determination of arterial blood gas and pH values. Possible reasons for the differences observed between the values obtained from the alternative sampling sites are suggested. If blood gas and pH measurements are required during hemodialysis, direct arterial puncture must be made to obtain an accurate result for clinical use. However, for sequential comparative studies of acid-base metabolism or respiratory function while on dialysis, repetitive fistula sampling appears valid.

Adult↗
PubMed1982

Effects of a jogging program on cardiovascular fitness and work performance of mentally retarded adults.

Changes in cardiovascular fitness and work performance of mentally retarded adults resulting from a jogging program were evaluated with randomly assigned experimental and control subjects using posttest measures from Cooper's 12-minute Run-Walk Test and timed samples of work performance. Pretest measures were utilized as covariates in analysis of covariance. Statistically significant results in both fitness and work performance favored the experimental group.

Adolescent↗