Occupational causes of disorders in the upper limbs.
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Biomedical subjects
Publications and source records attributed to P Buckle.
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Anecdotal reports suggest that obstructive sleep apnea syndrome (OSAS) patients may suffer from frequent nocturnal gastroesophageal reflux (GER) and that nasal continuous positive airway pressure may be an effective form of antireflux therapy in this population. To confirm these clinical impressions, we performed two consecutive days of 24-h esophageal pH monitoring, nocturnal esophageal pressure recording, and polysomnography on six OSAS patients complaining of regular nocturnal GER. On night one, the patients were untreated. Five of six subjects had abnormal amounts of nocturnal GER. Arousal, movement and swallowing were more frequent (p less than 0.043) and nadir intrathoracic pressure lower (p less than 0.005) in the 30 s prior to precipitous drops in esophageal pH (greater than or equal to 2 pH units) than during random control periods. A direct association between obstructive apneas and GER was not identified. On night two, nasal CPAP was administered and successfully treated apnea in five of six subjects. In these patients, there was also dramatic reduction in GER frequency and duration on CPAP. The mean percentage of time pH less than 4 dropped from 6.3 +/- 2.1 to 0.1 +/- 0.1 percent (p less than 0.025). We believe that OSAS may predispose to nocturnal GER by lowering intrathoracic pressure and increasing arousal and movement frequency. Nasal CPAP can correct these predisposing factors and reduce GER.
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We studied male patients (BMI = 27.6 +/- 3.4, mean +/- SD), mean age 54.1 +/- 8.9 years, with stable NYHA class 3-4 congestive heart failure (CHF) (LVEF = 24.3 +/- 11.5 percent) and normal daytime arterial blood gas values. These patients underwent three consecutive nights of full polysomnography; adaptation, control, and treatment with nasal CPAP. Each night's study was followed during the day by cognitive testing and multiple sleep latency tests (MSLT). The purpose of the study was to document the effect of nasal CPAP on these variables. The main findings of the study showed no significant differences between control and treatment nights with respect to the amount of Cheyne-Stokes respiration (CSR) observed, the nocturnal oxygenation, or sleep quality. Both subjective and objective measures of sleep quality showed no change from night to night. In addition, the degree of cognitive functioning and daytime sleepiness (as measured by MSLT) showed no significant differences between control and treatment nights. We conclude that short-term treatment with nasal CPAP in patients with CHF does not improve either CSR, nocturnal oxygenation, or sleep quality. Furthermore, most of our patients did not tolerate nasal CPAP therapy.
The importance of nasal airflow resistance in the pathogenesis of obstructive sleep apnea syndrome (OSAS) remains contentious. We performed formal nocturnal polysomnography (PSG) on OSAS patients under conditions of baseline and reduced nasal resistance to answer two main questions. First, to what degree does baseline nasal airflow resistance influence upper airway collapse in OSAS patients? Second, in what proportion of the OSAS population is baseline nasal resistance contributing to the pathogenesis of upper airway collapse? Our study group consisted of 10 patients with a wide range of OSAS severity. Six of these patients had symptoms and clinical evidence of chronic nasal obstruction which, in some, was associated with markedly elevated nasal resistance. A placebo (normal saline) was instilled in the nose of each patient on the night of baseline data collection. On the treatment night of the study, nasal resistance was reduced by application of topical vasoconstrictor and insertion of vestibular stents designed to dilate the area of the nasal valve. Posterior rhinomanometry was used to measure resistance to nasal airflow immediately before and after each PSG study. Although treatment was associated with a subjective improvement in sleep quality and mean drop in nasal resistance of 73% (P less than 0.001), there was no significant improvement in sleep architecture, nocturnal oxygenation, or the amount of apnea experienced by patients. The most significant improvement was a reduced number of arousals/hour from 52.4 +/- 12.4 on placebo to 43.7 +/- 10.2 on treatment (P less than 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)
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A technique based on surface plasmon resonance is described which can be used to detect changes of refractive index that occur when one partner of a molecular binding pair diffuses from solution to bind the other partner which is immobilised on a silver surface. Results for the molecular binding pairs; protein-antibody, hapten-antibody and DNA-DNA are described. Instrumentation necessary for implementation of the technique is detailed. Immunoassay of proteins and haptens is possible in less than one minute with a sensitivity of 10(-9) mol/l. Hybridisation of 10 fmoles of a 97 base target sequence on the 1 mm2 area of detection to an immobilised oligonucleotide probe can be detected in less than five minutes. Advantages of the technique include the ability to record the kinetics of binding reactions in "real time" and the lack of labels in this simple assay format. Methods of improving the sensitivity are discussed.
The role of ergonomics in existing rehabilitation programmes is considered through a review of studies undertaken both in the United Kingdom and elsewhere. In general, little consideration has been paid to what the rehabilitees are undertaking in their work or to how intervention at the workplace might be implemented. This occurs despite the evidence that ergonomic advice has been shown to be beneficial. Current approaches to rehabilitation stress the need for the patient to resume normal activities as soon as possible. It seems also prudent to identify ergonomic mismatches in the workplace as soon as possible during rehabilitation in order to reduce the number of repeat attacks. A number of examples have been presented which illustrate how ergonomics can help, and the dangers of inappropriate or delayed interventions. The occupational physician is considered to be a key individual in initiating ergonomic interventions. This is in keeping with the International Labour Office model of occupational health services.
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