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Biomedical subjects

G K Scadding

Publications and source records attributed to G K Scadding.

At least 55 records · Page 3Linked to original sources
PubMed1994

Acoustic rhinometry compared with anterior rhinomanometry in the assessment of the response to nasal allergen challenge.

Acoustic rhinometry was used to assess nasal airway patency objectively and was compared with the more established method of anterior rhinomanometry. Ten patients with allergic rhinitis underwent 15 nasal challenges with allergen to which they showed positive skin-prick tests. Responses were assessed by measuring the minimum nasal cross-sectional area (Amin.) using acoustic rhinometry and by measuring nasal airway resistance (NAR) using anterior rhinomanometry. The measurements of Amin. and NAR showed a significant negative correlation. Acoustic rhinometry appears to be superior to anterior rhinomanometry in quantifying the response to nasal allergen challenge and may be particularly useful in patients with initial nasal blockage.

Administration, Intranasal↗
PubMed1994

Reduction by Hoe 140, the B2 kinin receptor antagonist, of antigen-induced nasal blockage.

In subjects with allergic rhinitis to house-dust mite (HDM), antigen challenge produced a significant increase in nasal blockage but had no effect on nasal vascular permeability. The B2 kinin receptor antagonist, [D-Arg0,Hyp3,Thi5,D-Tic7,Oic8]-bradykinin (Hoe 140), 200 micrograms administered by intranasal aerosol 2 min prior to challenge with HDM, 500 u significantly reduced nasal blockage induced by the antigen challenge. The data are compatible with a role for B2 kinin receptors in the nasal response to challenge with antigen which is responsible for nasal blockage.

Adult↗
PubMed1994

Acoustic rhinometry in rhinological practice: discussion paper.

Acoustic rhinometry is a new technique which evaluates nasal obstruction by analysing reflections of a sound pulse introduced via the nostrils. The technique is rapid, reproducible, non-invasive and requires minimal cooperation from the subject. Unlike rhinomanometry it does not require airflow. A graph of nasal cross-sectional area as a function of distance from the nostril is produced, from which several area and volume estimates of the nasal cavity can be derived. The reliability of the method is greatest in the anterior nasal cavity, which is the site of the nasal valve. We have applied the technique to the study of normal nasal physiology in adults and children and to a range of pathological conditions. The role of acoustic rhinometry in diagnosis is somewhat limited compared to nasal endoscopy, but it is useful for nasal challenge and for quantifying nasal obstruction. Monitoring of medical and surgical therapy is a more promising application. In future, acoustic rhinometry is likely to be of particular help in evaluating childhood nasal obstruction, as it is well tolerated by children as young as 3 years old-a group of patients to whom objective tests have hitherto been difficult to apply.

Humans↗
PubMed1994

IgG subclass levels in chronic rhinosinusitis.

Sera from seventy-four adult patients with chronic or recurrent rhinosinusitis (mean duration 10.3 years) were tested for levels of total immunoglobulin and IgG subclasses. Fourteen (19%) had low levels of one of the major immunoglobulin classes and 23 (31%) had one or more IgG-subclass deficiencies, i.e. values less than the mean minus 2 standard deviations of a control population sample. Nineteen patients had low IgG3 levels. The group as a whole showed significantly low mean levels of IgG3, 46.9 +/- 19.5 mg/dl compared to 76 +/- 21 mg/dl for the controls, p < 0.0005 (Student's t-test). Since there was no clinical difference between those with and without IgG3 deficiency, there exists the possibility of an underlying immune defect, possibly involving heavy chain switching, in all these patients.

Adult↗
PubMed1993

The role of acoustic rhinometry in studying the nasal cycle.

The nasal cycle has been demonstrated in man using several techniques, including magnetic resonance imaging, anterior rhinoscopy, rhinomanometry, all of which have limitations due to expense, discomfort, limited scope or poor reproducibility. Acoustic rhinometry is a new technique which analyses nasal geometry throughout the nasal cavity, not just at the flow-limiting segment. Six adult volunteers were examined at 15-to 30-min intervals using acoustic rhinometry. The classical alternating cycle was seen in three subjects, a non-classical cycle was seen in two, and no cycle seen in one subject. Changes occurred throughout the nasal cavity and corresponded with fluctuations in subjective scores of obstruction and, in one case, with nasal resistance measurements. Acoustic rhinometry is a rapid, reproducible and non-invasive technique. This pilot study demonstrates that it has potential for studying in detail the physiology of the nasal cycle.

Acoustics↗
PubMed1991

CT of the paranasal sinuses and functional endoscopic surgery: a critical analysis of 100 symptomatic patients.

CT scans of 100 patients from the Rhinology Clinic at the Royal National Throat, Nose and Ear Hospital were reviewed in order to test the precepts forming the basis of functional endoscopic sinus surgery, especially as they relate to the radiological investigation. These were: (a) the site of origin of sinus infection, (b) The relevance of certain anatomical variants in the middle meatus to sinus infection and (c) The use of CT as the radiological method of diagnosis in all cases. Obstruction in the middle meatus and ostiomeatal complex was associated with an increased incidence of opacity in the sinuses but the primary site of disease was not established: the concept that sinus disease takes origin in the middle meatus was not proven. Anatomical variants in the middle meatus were not associated with an increase in sinus opacity and there was no evidence that these anomalies have any effect on sinus disease by causing middle meatal stenosis. The radiological assessment of patients with inflammatory naso-sinus disease should start with plain X-ray. CT is unnecessary as a routine examination. It should be reserved for the pre-operative assessment of patients for endoscopic surgery, its main function being to show important anatomical landmarks.

Endoscopy↗
PubMed1991

Functional endoscopic sinus surgery in the management of chronic rhinosinusitis. An objective assessment.

Considerable clinical success has been claimed for functional endoscopic sinus surgery but objective assessment of prospective series is lacking in the literature. Twenty-four patients with chronic rhino-sinusitis underwent assessment of symptoms by visual analogue scoring, nasomucociliary function by ciliary beat frequency, olfaction by qualitative olfactometry and nasal airway resistance by anterior rhinomanometry pre- and post-operatively. This demonstrated a significant improvement in all symptoms examined and in ciliary beat frequency. Quantitative olfaction and anterior rhinomanometry were not improved despite diminished symptoms. These results offer quantitative evidence of clinical improvement following functional endoscopic sinus surgery which supports the pathophysiological concepts on which the technique is based.

Adult↗
PubMed1991

Immunologic aspects of chronic sinusitis.

The role of immunological defence mechanisms in the development of acute recurrent or chronic sinusitis is obviously of considerable importance but the incidence of such immune problems is unknown. To elucidate this situation, a prospective study of 47 patients with chronic rhino-sinusitis were examined for abnormalities of serum immunoglobulins, both major class and subclasses. Deficiencies of minor IgG subclasses may be obscured by only measuring the major IgG class and should be specifically sought in clinically suspicious cases. The clinical and therapeutic implications are considered.

Adolescent↗
PubMed1990

Assessment of nasal obstruction. A comparison between rhinomanometry and nasal inspiratory peak flow.

In several conditions objective assessment of nasal obstruction would be of great value. In this study we have compared two different methods for this purpose. Anterior rhinomanometry is a well established method, which measures nasal airway resistance (NAR). This was compared with nasal inspiratory peak flow (NIPF) measured with a Youlten peak flow meter. The assessments were undertaken in patients with allergic rhinitis, before and after challenge with hyperosmolar saline solution. After challenge there was a fall in NIPF value as a mean of 17.4%, that was mirrored by a rise in NAR of 15.6%. There was also a statistically significant negative linear correlation between these two methods (p less than 0.01). We conclude that NIPF is a cheap, easily performed and quick method suitable for assessing nasal airway patency in e.g. allergics during treatment and during challenge.

Airway Resistance↗
PubMed1989

Nasal histamine release following hyperosmolar and allergen challenge.

Allergic rhinitis is characterised by symptoms of sneezing, itching of the nose with watery secretions, and nasal obstruction. We have previously shown that patients can have the diagnosis of allergic rhinitis confirmed by nasal provocation tests and assessment of nasal inspiratory peak flow (NIPF) after specific allergen or hyperosmolar challenge. We now show that histamine is released into the nasal lavage fluid in response to such challenges. Saline lavage alone results in detectable histamine levels in the order of 5 ng/ml, but in the presence of allergen (HDM) there is a significant increase in histamine release in atopics but not in control subjects. With hyperosmolar challenge, atopics showed a biphasic response in that histamine release was increased with 1.8% and 3.6% saline but returned to baseline with 5.4% and 7.2% saline, then showing a further increase with 9.0% saline. This raises the possibility of two populations of responsive mast cells. Hyperosmolar challenge leads to symptoms of nasal itch and sneezing as well as histamine release in atopics but not in controls. This suggests that hyperosmolar challenge can be used as a simple diagnostic test for allergic rhinitis and may provide a model for nasal hyper-reactivity.

Adolescent↗
PubMed1988

Poor sulphoxidation ability in patients with food sensitivity.

Patients with well defined reactions to foods were examined for their ability to carry out both sulphur and carbon oxidation reactions by using carbocisteine and debrisoquine as probe compounds. The proportion of poor sulphoxidisers (58 of 74) was significantly greater than that of a previously determined normal control population (67 of 200; p less than 0.005). The proportion of poor carbon oxidisers was not significantly different from the controls. Metabolic defects may play a part in the pathogenesis of adverse reactions to foods.

Adult↗
PubMed1988

Nasal response to allergen and hyperosmolar challenge.

Rhinitis causes both clinical and social discomfort to patients, and in clinical practice is often underdiagnosed. We have examined a simple method for the assessment of a positive nasal provocation test to help in the diagnosis of rhinitis. In patients with histories suggestive of house dust mite (HDM) sensitivity and positive skin-prick tests or specific IgE to Dermatophagoides pteronyssinus, there was a fall in nasal inspiratory peak flow (NIPF) following nasal challenge with allergen. This was not seen in control subjects or in pollen-sensitive patients when challenged with house dust mite. Frequency of sneezing and degree of rhinorrhoea increased in these patients following challenge, and based on these findings we propose a simplified scoring system for the diagnosis of allergic rhinitis. We examined non-specific nasal reactivity using hyperosmolar solutions as a challenge system and found that allergic subjects responded with a fall in NIPF, although the clinical response was not identical to that seen with allergen. Control subjects did not respond to hyperosmolar challenge.

Adolescent↗
PubMed1987

Basophil histamine release. A study in allergy to suxamethonium.

A patient who suffered a severe hypotensive episode after induction of anaesthesia, was subsequently found to show positive skin-test responses to suxamethonium. Investigation revealed that suxamethonium induced basophils from the patient to release histamine to an extent comparable to that found after exposure to anit-IgE. Basophils from control subjects showed no such response. Basophil histamine release may offer a useful approach to the investigation of adverse drug reactions.

Adult↗