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Biomedical subjects

R Eccles

Publications and source records attributed to R Eccles.

At least 37 records · Page 2Linked to original sources
PubMed2000

Changes in unilateral nasal airflow in patients with seasonal allergic rhinitis measured in and out of season.

OBJECTIVE: Nasal congestion is a common complaint of patients suffering from seasonal allergic rhinitis yet there are very few investigations which have studied the objective changes in nasal airflow in and out of season. The aim of this study was to investigate the changes in nasal airflow in and out of season. METHODS: In the present study unilateral nasal airflow was measured in and out of the pollen season in 13 patients with seasonal allergic rhinitis. Unilateral nasal airflow was measured using posterior rhinomanometry at an inspiratory reference pressure of 75 Pa. RESULTS: There was no significant difference between median total nasal airflow in season (325 cm3/s) and out of season (324 cm3/s) (P = 0.15, n = 13) yet there was a significant difference between maximum unilateral airflow in season (278 cm3/s) and out of season (234 cm3/s) (P = 0.007, n = 26). CONCLUSION: The results of the present study indicate that although patients with seasonal allergic rhinitis may experience a sensation of nasal congestion at the start of the pollen season there is little or no change in total nasal airflow and unilateral nasal airflow may be increased.

Adolescent↗
PubMed2000

Nasal airflow in health and disease.

This review examines our present understanding of the physiology, pathophysiology and pharmacology of nasal airflow. The main aim of the review is to discuss the basic scientific and clinical knowledge that is essential for a proper understanding of the usefulness of measurements of nasal airflow in the clinical practice of rhinology. The review concludes with a discussion of the measurement of nasal airflow to assess the efficacy of surgery in the treatment of nasal obstruction. Areas covered by the review include: influence of nasal blood vessels on nasal airflow; nasal valve and control of nasal airflow; autonomic control of nasal airflow; normal nasal airflow; nasal cycle; central control of nasal airflow; effect of changes in posture on nasal airflow; effect of exercise on nasal airflow; effect of hyperventilation and rebreathing on nasal airflow; nasal airflow in animals; cerebral effects of nasal airflow; sensation of nasal airflow; sympathomimetics and sympatholytics; histamine and antihistamines; bradykinin; and corticosteroids.

Administration, Intranasal↗
PubMed2000

Coughing and choking in motor neuron disease.

OBJECTIVES: To assess the frequency and severity of coughing and choking episodes, possible related factors, and their association with chest infections in patients with motor neuron disease (MND). METHODS: Thirty seven patients with MND and 23 healthy volunteers were studied. Cough was assessed using a questionnaire and a 3 day diary, and volitional cough quantified by peak cough flow and sound intensity. Other clinical symptoms, smoking habit, affective state, oral secretions, bulbar signs, and quantitative assessments of swallowing and respiratory function were documented. RESULTS: Patients with MND coughed and choked significantly more often and to a greater degree than the healthy volunteers (26 of 37 patients with MND and 2 of 23 volunteers, p<0.001). Female sex, older age, abnormal speech, reduced swallowing capacity, and low forced vital capacity (FVC)% predicted were each significantly associated with excessive coughing and choking episodes in patients with MND. Smokers had significantly more severe and prolonged episodes of coughing and choking than non-smokers (p<0.05). Patients with upper motor neuron bulbar signs had a greater tendency to severe and prolonged episodes of coughing and choking than those without (p<0. 05). Chest infections were reported only rarely among the patients who coughed and choked. CONCLUSIONS: Coughing and choking episodes are common in patients with MND but infrequently associated with overt chest infection. Upper motor neuron bulbar signs may both promote factors (for instance, dysphagia) which trigger cough and reduce volitional capacity to suppress it.

Aged↗
PubMed2000

Antitussive efficacy of dextromethorphan in cough associated with acute upper respiratory tract infection.

Dextromethorphan is one of the most widely used antitussives for the treatment of cough associated with acute upper respiratory tract infection. However, there is very little data to support the efficacy of dextromethorphan in this disease state. This aim of this study was to obtain more information about the efficacy of a single dose of 30 mg dextromethorphan in the treatment of cough associated with acute upper respiratory tract infection. The study was a double-blind, stratified, randomized and parallel group design. Both objective and subjective measurements of cough were recorded over 10-min recording periods in a quiet room before (baseline) and at 90, 135 and 180 min after treatment. Forty-three patients (30 females and 13 males), mean age 22.9 years (range 18-46 years), with acute dry or slightly productive cough and otherwise healthy were included in the study. Patients were randomized to placebo treatment (n = 22) and dextromethorphan treatment (n=21). The results showed similar trends in both treatment groups with statistically significant reductions (P < 0.05) in cough sound pressure level (CSPL), cough frequency (CF) and subjective scores for cough severity within treatment groups but little difference between the treatment groups during the study period. The only statistically significant difference between treatment groups was for the mean CSPL changes from baseline to 90 min (P=0.019). There was a significant positive correlation between CSPL and CF (r = 0.752, P= 0.000) for changes in cough measurements from baseline to 90 min after treatment and this indicates that CSPL may be a useful measure of cough severity. This study provides very little if any support for clinically significant antitussive activity of a single 30 mg dose of dextromethorphan in patients with cough associated with acute upper respiratory tract infection.

Adolescent↗
PubMed1999

Effect of submucosal diathermy to the inferior turbinates on unilateral and total nasal airflow in patients with rhinitis.

The efficacy of the controversial treatment of submucosal diathermy to the inferior turbinates (SMDIT) was evaluated objectively. Twenty-seven patients with chronic rhinitis were investigated by hourly posterior rhinomanometry to assess changes in total and minimum (Fmin) and maximum (Fmax) unilateral nasal airflow over 5 h, before and 2-3 months after standardized SMDIT treatment. Nasal airflow was recorded at a sample pressure of 75 Pa and the results are reported as medians with interquartile range. Whilst SMDIT caused a significant 51% increase (p < 0.0001) in total nasal airflow from 246 cm3/s (131) to 371 cm3/s (133) the changes in unilateral airflow provided further evidence which strongly supported the benefits of this operation. Unilateral Fmin significantly increased by 136% (p < 0.0001) from 69 cm3/s (82) to 163 cm3/s (74) and Fmax significantly increased by 23% (p < 0.0001) from 171 cm3/s (74) to 211 cm3/s (59). The effect of surgery was to "splint" to the turbinate in a state of relative vasoconstriction. Our findings therefore provide functional evidence of submucosal fibrosis following SMDIT. The greater percentage change in unilateral Fmin suggests that this parameter is a more sensitive index of the effect of nasal surgery than total nasal airflow measurements. The importance of considering the nose as two separate airways in the evaluation of nasal treatments is emphasized.

Adolescent↗
PubMed1998

Development and application of a new method for amplification and detection of human rhinovirus RNA.

A method based on nucleic acid sequence based amplification (NASBA) was developed for detection of rhinovirus RNA. Appropriate collection and storage conditions for maintenance of rhinovirus RNA integrity in clinical samples was determined. Two silica-based extraction methods were evaluated for preparation of RNA from virus isolates and clinical samples. Primers and probes were selected from the non-translated region at the 5' end and from VP4 of sequenced rhinoviruses. Amplified products were detected by 'in-solution' hybridization, with analysis by polyacrylamide gel electrophoresis (enzyme linked gel assay or ELGA), and by a microtitre-based plate hybridization assay. Using propagated picornavirus isolates in vitro the rhinovirus NASBA, with detection of amplified sequences by ELGA or plate hybridization, was confirmed as sensitive and specific for detection of rhinovirus RNA. The method was applied successfully to analysis of rhinovirus sequences in clinical samples from individuals with respiratory-tract symptoms. Rhinovirus NASBA will be useful for studies of the molecular epidemiology of respiratory infections and monitoring of response to anti-rhinovirus therapy.

Common Cold↗
PubMed1998

Acoustic rhinometry: an explanation of some common artefacts associated with nasal decongestion.

The nasal cavities of 51 healthy volunteers were examined using acoustic rhinometry before and after nasal decongestant. Several specific dimensions were studied, which included the minimum cross-sectional area, and three volumes corresponding to the anterior, middle and posterior regions of the nasal airway. An average acoustic rhinometry trace was constructed for the whole group of subjects, before and after decongestion, from data extracted from the raw data files written to the computer hard disk for each subject. A 27.5% (P < 0.0001) increase in the minimum cross-sectional area was observed, with no shift in its position. The greatest increase in nasal dimensions was seen in the anterior and middle parts of the nose, however, significant changes were also seen in the posterior nasal cavity and post nasal space. There are a number of possible sources of artefact. First, confusion of the first and second minima may produce apparent movement of the minimum cross-sectional area following nasal decongestion. Second, a postulated change in the acoustic path length may lead to apparent changes in volume in certain regions of the nose. Third, a variable and uncontrollable degree of sound energy loss will occur into the opposite nasal cavity beyond the posterior border of the septum. An apparent increase in the dimensions of this region will be seen as the opposite cavity decongests. We feel that all users of the acoustic rhinometer need to be aware of these potential sources of artefact, and attention needs to be focused on an agreed definition of the components of the acoustic rhinometry trace.

Acoustics↗
PubMed1998

Physiological versus pharmacological decongestion of the nose in healthy human subjects.

In the present study we were interested to determine whether the maximum unilateral nasal airflow associated with the nasal cycle (Fmax physiol) was equivalent to the maximum unilateral nasal airflow that could be achieved by the application of a topical nasal decongestant (Fmax pharmacol). Eight healthy subjects (three male and five female, aged between 19-28 years) were recruited for this study. Unilateral nasal airflow was measured using posterior rhinomanometry at the inspiratory reference pressure of 75 Pa by alternately occluding each nostril with surgical tape. The study was run over 2 consecutive days. On day one, measurements of unilateral nasal airflow were performed every hour for 8 h in each subject and Fmax physiol was found to be 265 cm3/sec (147) (median and interquartile range). On day 2 the median unilateral nasal airflow before application of the nasal decongestant was 171 cm3/sec (140) and this increased to 251 cm3/sec (127) (p = 0.046) at 15 min and to 278 cm3/sec (134) (p = 0.005) at 45 min after application of the decongestant (Fmax pharmacol). A paired comparison of Fmax physiol and Fmax pharmacol showed that these nasal airflow measurements were not significantly different (p > 0.999). The results show that there was no difference between the maximum physiological decongestion produced during the course of the nasal cycle and that produced pharmacologically by a topical nasal decongestant. This indicates that the point of maximal sympathetic vasoconstrictor tone occurring during the nasal cycle causes a constriction of the nasal venous sinuses that is equal to the constrictor response that can be achieved by applying a topical sympathomimetic medication.

Administration, Intranasal↗
PubMed1998

Effect of pseudoephedrine on nasal airflow in patients with nasal congestion associated with common cold.

The aim of this study was to investigate the efficacy of pseudoephedrine as a nasal decongestant. Patients with nasal congestion associated with common cold received two doses of medication separated by 4 hours, either 60 mg pseudoephedrine (n = 20), or placebo (n = 20). Unilateral nasal airflow was measured over a 7-hour period to record the spontaneous changes in nasal airflow associated with the nasal cycle. Minimum (F MIN) and maximum (F MAX) unilateral nasal airflows were defined as the minimum and maximum nasal airflow values for each nasal passage recorded during the 7-hour period of the study. There was no significant difference in F MAX between the two treatment groups yet there was a significant difference in F MIN (p < 0.05). No difference in total nasal airflow (TNAF) between treatment groups was found, either before or after treatment (p > 0.05). The results demonstrate that (TNAF) is not as sensitive a measure of decongestion as F MIN. The findings of this study show that pseudoephedrine had no effect on the decongestion phase of the nasal cycle, but did significantly limit the congestion phase. The decongestant action may be explained by the sympathomimetic supplementing the natural sympathetic nervous activity to the nasal blood vessels.

Adolescent↗
PubMed1997

Assessment of the antitussive efficacy of codeine in cough associated with common cold.

Codeine is generally accepted as the standard antitussive against which new antitussive medications are compared. This presents a problem because the support for codeine's antitussive activity comes from studies on cough in animals, and chronic and induced cough models in man, whereas antitussives are almost exclusively used for the treatment of cough associated with acute upper respiratory tract infection (URTI). The aims of this study were twofold. Firstly, to study the antitussive efficacy of codeine in cough associated with URTI and, secondly, to validate a sound meter as tool for quantifying cough. The efficacy of codeine was assessed in a double-blind, stratified, placebo-controlled, parallel-group, clinical trial using three different measures of cough: cough sound-pressure levels (CSPLs) measured on a sound meter; subjective scores of cough severity; and cough frequency recorded by means of a microphone connected to an ink-pen recorder. A group of 82 subjects (51 females and 31 males; mean age 23.5 years, range 18-46 years) with cough owing to acute URTI were included in the study. The study took place on two separate study days. On study day 1 cough measurements were made before and 90 min after treatment with a single dose of either 50 mg codeine or matched placebo in capsule form. The same three measures of cough were repeated 2-5 days later (study day 2). On study day 1 a highly significant (P < 0.0001) decrease in all three measures of cough was found after treatment with both placebo and codeine yet there was no significant difference between the treatment groups. A highly significant (P < 0.0001) decrease in the three measures of cough was also found between days 1 and 2. The results demonstrate that codeine is no more effective than placebo in reducing cough associated with acute URTI, as measured by CSPLs, cough frequency or subjective symptom scores. This result might be explained on the basis of two central pathways for cough; a reflex pathway via the brain-stem which is sensitive to codeine and a voluntary pathway via the cortex which is unaffected by codeine. The results also demonstrate that the sound-level meter appears to be a potentially useful investigative tool for the assessment of cough and antitussive efficacy.

Adolescent↗
PubMed1997

Spontaneous changes of unilateral nasal airflow in man. A re-examination of the 'nasal cycle'.

It is now over 100 years since Kayser (Archiv für Laryngol Rhinol 1895; 3: 101-120) first reported in the scientific literature that the human nasal passages exhibit spontaneous changes in unilateral nasal airway resistance, yet our understanding of this unusual phenomenon is still very confused. Spontaneous, reciprocal changes in unilateral nasal resistance are often referred to as a "nasal cycle" and although this term is now commonly used to describe spontaneous changes in nasal resistance in man and animals, there is little evidence for any true periodicity. A major problem in increasing our knowledge and understanding of the so-called "nasal cycle" is that most studies have relied on simple descriptions of the changes in nasal resistance and have not developed any numerical parameters to quantify the changes in resistance over time. This lack of definition of what actually constitutes a nasal cycle has meant that the literature of the present day generally accepts the views put forward by Heetderks (Am J Med Sci 1927; 174; 231-244) and Stoksted (Acta Otolaryngol (Stockh) 1953; Suppl 109: 159-175) that around 80% of the healthy population exhibit a regular cycle. In order to define the characteristics of the spontaneous changes in nasal airway resistance we have used numerical measures of reciprocity and also developed a measurement of the division of airflow between the nasal passages over time. With these two parameters it is possible to describe the nature of the spontaneous changes in airflow in numerical terms and to define what exactly constitutes a nasal cycle. Fifty-two volunteers underwent hourly measurement of unilateral nasal airflow for 8 h. For each volunteer, two values were derived from the graph of unilateral nasal airflows against time; the correlation coefficient between unilateral airflows (r) and the airflow distribution ratio between the two nasal airways (ADR). The spread of different types of airflow pattern (nasal cycle) throughout the population was illustrated by plotting r against ADR for each subject. A nasal cycle was defined as having an r value between -0.6 and -1.0, and an ADR value between 0.7 and 1.0. Only 21% (11 of the 52 volunteers) exhibited airflow patterns that could be defined as a nasal cycle in these terms. This finding contradicts the generally accepted, but undefined, view that around 80% of the population exhibit a regular nasal cycle. The numerical definition of a nasal cycle in terms of both reciprocity and airflow distribution, as described in this paper may help to clarify our understanding of this interesting phenomenon and allow rhinologists to describe the spontaneous changes in nasal airflow in more exact terms than have been used previously in the literature.

Adult↗
PubMed1997

Changes in nasal nitric oxide concentration associated with symptoms of common cold and treatment with a topical nasal decongestant.

Nitric oxide (NO) is known to play a role in the non-specific host defence mechanism. Furthermore, it has been proposed that NO may be important in respiratory defence against the viruses which cause the common cold. Indeed, elevated NO levels have previously been observed in orally expired air during upper respiratory tract infection (URTI). We wanted to investigate further the role of NO in the host response to URTI. Total nasal airway resistance (tNAR) and nasal NO levels were obtained during symptomatic URTI in 97 subjects. Of these, 80 received treatment with either oxymetazoline or a placebo spray. Post-treatment tNAR and NO levels were obtained 60 min after treatment. Measurements of NO were also repeated 4-6 weeks later, when subjects were healthy, (n = 82). NO levels were measured using a chemiluminescence gas analyse whilst tNAR was measured using posterior rhinomanometry. The mean pre-treatment NO level (1063 +/- 541 ppb) was shown to be reduced significantly after treatment with oxymetazoline (827 +/- 373ppb), p < 0.0001. The mean pre-treatment tNAR, 0.42 Pa cm-3 sec-1, was also reduced significantly to 0.21 Pa cm-1 sec-1 (p < 0.001) after treatment with oxymetazoline. There was no significant correlation between the change in NO levels and change in tNAR following treatment with oxymetazoline (p. corrected for ties = 0.011, p = 0.98. No significant difference was found between NO levels obtained during URTI (1130 +/- 444 ppb) when compared to values obtained when healthy (1197 +/- 361 ppb), p = 0.25. These results demonstrate that treatment with a topical nasal decongestant spray causes a reduction in nasal NO levels. We propose that this occurs as an indirect consequence of the vasoconstrictor actions of oxymetazoline. Since no change in NO levels was observed during URTI, we propose that the NO synthase responsible for NO production in the nose responds in a different manner to that in the lungs.

Administration, Topical↗
PubMed1997

The effects of oxymetazoline on lysozyme secretion from the human nasal mucosa.

Lysozyme is a protein secreted by nasal submucosal glands. Its secretion is under cholinergic control. It is considered important in nasal defence as it enzymatically hydrolyses peptidoglycan bonds in bacterial cell walls and has specific activity against Gram-positive bacteria in vitro. Oxymetazoline is freely available as a non-prescription nasal decongestant. Some recent work has shown that it has no effect on histamine-induced plasma exudation but little is known about its effects on glandular secretion. The current study is a randomized controlled study that investigates the effect of topical oxymetazoline on the total protein and lysozyme content of nasal fluid. Thirty healthy volunteers were randomized to receive either a normal saline nasal spray (placebo) or an active spray of oxymetazoline, 0.05% (w/v) in saline. NAR was assessed in all subjects using posterior rhinomanometry and nasal lavage before the application of the spray and again 10 min later. The results were analysed using non-parametric statistics. There was a significant decrease in both the lysozyme and total protein content of nasal lavage after application of oxymetazoline when compared with placebo (p < 0.05). A possible mechanism for the observed decease in total protein and lysozyme would be that the vasoconstrictor effects of oxymetazoline also apply to the vessels supplying nasal submucosal glands and that this decrease in blood supply is reflected by a decrease in secretion.

Administration, Intranasal↗
PubMed1997

Relationship between nasal nitric oxide concentration and nasal airway resistance.

In the present study the relationship between nasal nitric oxide (NO) concentration and nasal airway resistance (NAR) was investigated in healthy volunteers at rest. Endothelially derived NO is established as a potent vasodilator and as such may be involved in the regulation of the nasal vasculature. Nasal airway resistance is dependent upon the tone of the nasal vasculature. It is therefore suggested that NO may play a role in the regulation of nasal airway resistance. Nasal NO concentration and nasal airway resistance were measured in 123 healthy volunteers. Posterior rhinomanometry was used to obtain the total and unilateral nasal airway resistance. Nasal NO concentration was measured from both the left and the right nostrils, consecutively, during a 20-sec breath hold, using a chemiluminescence gas analyser. NO was measured by sealing a cannula into each nostril consecutively and drawing air through both nasal passages. The results demonstrated that there was no significant difference between the concentrations of NO from the left and the right nostrils (p = 0.7). This indicated that the sampling technique provide a measure of nasal NO which was independent of the side of the nose used for sampling. The mean (+/- s.d) NO concentration sampled from the left nostril was 1,145 +/- 367 ppb. The mean NO concentration sampled from the right nostril was 1,163 +/- 401 ppb. There was a highly significant correlation between the right and left measurements (rho, corrected for ties = 0.95, p < 0.0001). The mean total NAR (+/- s.d) was 0.25 +/- 0.06 Pa/cm3/s. The mean left NAR was 0.50 +/- 0.28 Pa/cm3/s, whilst the mean right NAR was 0.48 +/- 0.31 Pa/cm3/s. There was no significant correlation between total NAR and the left nasal NO concentration (rho = 0.10) or total NAR and right nasal NO concentration (rho = 0.05). Similarly, no correlation was found between the left or right unilateral NAR and left or right nasal NO concentration, respectively. The results of the present study on healthy volunteers demonstrate that the nasal concentration of NO is not related to the total NAR. However, the present study cannot eliminate the possibility that nasal NO may be involved in the regulation of unilateral NAR.

Adult↗
PubMed1996

Acoustic rhinometry: do we need a standardized operating procedure?

The usefulness of a standardized operating procedure for acoustic rhinometry was assessed in a study on 51 healthy volunteers. Nasal measurements were made with acoustic rhinometry before and after application of a topical nasal decongestant. Our standard operating procedure used three consecutive readings of anterior nasal volume to obtain a valid estimate of mean nasal dimensions. The mean measurement was only accepted as valid if the three readings had a coefficient of variation (CV) of less than 20%. Twenty-two out of 192 (11.5%) nasal cavities required more than three consecutive readings to achieve this. Our data show that the error encountered by relying on a single reading of an acoustic trace can be greater than the changes caused by the topical nasal decongestant and that multiple readings using a standard operating procedure are essential to obtain valid data.

Acoustics↗
PubMed1996

A role for the nasal cycle in respiratory defence.

This review describes the phenomenon of the nasal cycle, which consists of periodic congestion and decongestion of the nasal venous sinusoids. The hypothesis is put forward that the nasal venous sinusoids participate in respiratory defence by generation of plasma exudate. This hypothesis is based on recent studies, which have shown that the nasal venous sinusoids have a fenestrated endothelium and that the nasal cycle is increased during periods of nasal infection; and also on a series of older observations in the literature, which link the generation of nasal fluid to the decongestion of nasal venous sinusoids. It is proposed that the periodic congestion and decongestion of nasal venous sinusoids may provide a pump mechanism for the generation of plasma exudate, and that this mechanism is an important component of respiratory defence.

Airway Resistance↗