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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
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↗
PubMed1987

Anti-cardiolipin antibodies in neurological disorders: cross-reaction with anti-single stranded DNA activity.

Antiphospholipid (PL) antibodies have been detected in sera from patients with chronic neurological diseases associated with disorders of immunity. In an isotype specific radioimmunoassay for anti-cardiolipin (CL) antibodies, we found IgM anti-CL (greater than 2 s.d. above mean of controls) in 17/25 (68%) patients with myasthenia gravis (MG), 8/25 (32%) with the Lambert-Eaton myasthenic syndrome (LEMS), 5/17 (29%) with multiple sclerosis and 3/11 (27%) cases of migraine. IgG anti-CL was only found in low titres in sera from 10 patients with MG and three with LEMS. Significant anti-CL activity could not be detected in sera from nine patients with acute Guillain-Barré Syndrome (GBS), 12 chronic cases of epilepsy, 8/9 with oat cell carcinoma and 9/10 with acute stroke. Further tests on 39 sera with the highest anti-CL activity, from all of the above disease groups, showed a significant correlation between IgM anti-CL and IgM anti-ss DNA activities. In a series of competitive inhibition assays six sera from patients with MG were shown to have a proportion of both specific and cross-reactive IgM anti-CL and IgM anti-ss DNA antibodies. Anti-phospholipid antibodies occur in certain neurological diseases, at lower titres than seen in SLE, yet their cross-reactive binding to ss DNA suggests similar antibacterial origins as have been proposed for lupus auto-antibodies. In the absence of overt infection they might reflect a breakdown of tolerance for non-organ specific membrane antigens in diseases with predominantly organ specific membrane bound putative autoimmunogens.

Antibodies, Antinuclear↗
PubMed1986

Low dose sublingual therapy in patients with allergic rhinitis due to house dust mite.

In a double-blind placebo-controlled cross-over trial, low dose sublingual therapy with house dust mite was effective in relieving symptoms in 72% of the group of patients with perennial rhinitis due to house dust mite (P less than 0.03). Following active treatment, there was a significant increase in morning peak nasal inspiratory flow rate (P less than 0.01) in those who improved (thirteen out of eighteen) and resistance to nasal provocation with house dust mite also increased, in some cases up to 1000-fold (P less than 0.05). Oral therapy is safe and avoids the side effects of desensitizing injections which can be serious. The potential for oral desensitization is great and further studies on this form of treatment are needed.

Administration, Oral↗
PubMed1986

Anti-acetylcholine receptor antibodies induced in mice by syngeneic receptor without adjuvants.

Acetylcholine receptor (AChR)-bearing membranes from the BC3H-1 cell lines were injected, without adjuvant, either intrathymically (i.t.) followed by intraperitoneal (i.p.) booster doses, or i.p. alone, into (C57BL X BALB/c)F1 mice. Over 75% of the animals developed serum anti-AChRs which reacted with the cell-line AChR and with normal mouse endplate AChR. The titres were within the lower range of those of myasthenia gravis patients, and some mice showed reduced miniature endplate potential (m.e.p.p) amplitudes. these results indicate that loss of tolerance to acetylcholine receptors can result from immunization against syngeneic AChR without adjuvant. This approach may provide a useful model for studying mechanisms of autoimmunity against acetylcholine receptor.

Action Potentials↗
PubMed1985

The long term experience of thymectomy for myasthenia gravis.

A retrospective survey of the records of 287 patients with generalised myasthenia gravis treated at New End Hospital and later at the Royal Free Hospital by anticholinesterase drugs, with or without thymectomy, between the years 1942 and 1976, shows that 62% of patients were improved. The timing of the operation, the grading of disease and the age and sex of the patient did not greatly influence overall results. The poor diagnosis of thymic tumours was confirmed in this series. A decrease occurred in the number of patients achieving complete remission after 1961, although the proportion of patients improving did not fall. It is possible that anticholinesterase therapy may alter the response to thymectomy.

Age Factors↗
PubMed1983

Myasthenia gravis. Pathogenesis and current concepts in management.

Myasthenia gravis is a disorder of autoimmunity in which neuromuscular transmission is impaired by autoantibodies to the acetylcholine receptor (AChR). There is evidence for more than one form of the disorder with differing genetic susceptibilities. The aetiology is unknown, but thymic involvement is suggested by abnormal histology and by the beneficial response of the disorder to thymectomy in more than two-thirds of patients. Thymectomy is indicated in most patients unless the symptoms are minimal or are confined to the extraocular muscles alone, or the patient is elderly. Thymectomy alone results in remission in about one-third of patients, but, in addition, most patients require symptomatic anticholinesterase drugs to prolong the action of acetylcholine at the muscle end-plate. Over-dosage of these drugs can also cause weakness. Immunosuppression with corticosteroids or azathioprine may also improve myasthenia; at present, these drugs are used mainly in patients who do not respond to thymectomy or in those patients considered unsuitable for operation. Plasma exchange can cause a rapid, though temporary, involvement in myasthenia, but it probably has no long term place in its treatment. Future therapy will probably involve specific immunotherapy, such as anti-idiotype antibodies.

Cholinesterase Inhibitors↗
PubMed1983

Glomerulonephritis, thymoma and myasthenia gravis.

Three patients with myasthenia gravis, in whom a thymoma had been removed during total thymectomy four to 14 years earlier, developed glomerulonephritis presenting as the nephrotic syndrome. All had been treated previously by plasma exchange and were receiving azathioprine. Two were also taking prednisolone. Serum immune complexes containing IgM were present in all three. Renal histology showed either focal segmental glomerulosclerosis, minimal change lesion or focal proliferative glomerulonephritis. No immunoglobulin deposits were seen. Two patients lost their proteinuria on high dose corticosteroid therapy and their renal function improved. Glomerulonephritis occurred in nine per cent of patients with thymoma receiving immunosuppressive treatment with azathioprine for more than two years. We suggest that this treatment may be implicated in its aetiology.

Adult↗