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Biomedical subjects

A Forsyth

Publications and source records attributed to A Forsyth.

36 records · Page 2Linked to original sources

Lung function after coronary artery surgery using the internal mammary artery and the saphenous vein.

Lung volumes and arterial blood gas tensions in patients undergoing coronary artery surgery were compared in 77 patients given an internal mammary artery graft (group 1) and 33 patients given a saphenous vein graft only (group 2). Patients in both groups developed a severe restrictive ventilatory defect after surgery, more pronounced in those receiving an internal mammary artery graft. Mean (SEM) vital capacity in groups 1 and 2 was reduced to 36% (1.2%) and 45% (2.0%) of preoperative values on the second postoperative day (1.56 and 1.85 1 respectively), with some recovery by day 4 to 56% (1.2%) and 63% (2.1%) of preoperative values. The mean (SEM) arterial oxygen tension was 7.34 (0.13) kPa for group 1 and 7.46 (0.20) kPa for group 2 on day 2, rising to 8.39 (0.13) and 9.01 (0.23) kPa on day 4. Analgesic requirements were greater in the group receiving an internal mammary artery graft. Possible explanations for the differences between the effects of the two grafts include the higher frequency of pleurotomy, the placing of pleural drains, and additional surgical trauma when internal mammary artery grafts are used.

Adult

Thiomersal allergy and vaccination reactions.

Thiomersal is the preservative in all toxoid vaccines routinely administered to children in the UK, but exposure from other sources is uncommon. Delayed hypersensitivity to thiomersal was demonstrated in 1% of individuals attending the Contact Dermatitis Investigation Unit, and 50 of these patients with positive patch tests to thiomersal were studied. Cross-reaction with other mercurials occurred in 17 of 29 patients tested (59%). 31 of the patients replied to a questionnaire regarding vaccination reactions, and were compared with case-controls matched for age, sex, and site of dermatitis. 4 patients in each group reported reactions to vaccines which contained thiomersal, suggesting that thiomersal hypersensitivity was not associated with an increased risk of vaccination reactions. However, individual cases of severe reactions to thiomersal demonstrate a need for vaccines with an alternative preservative.

Adolescent

Allergy to non-toxoid constituents of vaccines and implications for patch testing.

We report 3 patients with persistent symptoms at vaccination sites. All were allergic to aluminium and one to thiomersal and neomycin too. Aluminium allergy causes false positive patch test reactions and we propose methods of patch testing patients with symptoms at vaccination sites in order to avoid this problem. The practical relevance of allergy to non-toxoid constituents of vaccines is discussed.

Aluminum

Inoperable aortic stenosis in the elderly: benefit from percutaneous transluminal valvuloplasty.

Eight patients with severe symptomatic calcific aortic stenosis were considered to be unsuitable for valve replacement. Four were admitted with pulmonary oedema and three in cardiogenic shock and one had angina at rest. With the use of echocardiographic and radiographic guidance percutaneous transluminal aortic valvuloplasty was carried out. Aortic gradients were reduced by an average of 40%. All four patients who presented with cardiac failure improved immediately and remained well six months later. The patient with angina was symptom free at nine months. Two of the three patients who presented in cardiogenic shock improved immediately and were well nine and three months later. The other patient died four hours after the procedure. Doppler echocardiographic studies showed a slight initial increase in aortic incompetence, but this did not worsen and valvar gradients remained improved three and six months later. Percutaneous valvuloplasty of the aortic valve is an effective therapeutic option in patients with severe calcific aortic stenosis who are unfit for surgery. Its role as an alternative to surgery has not been considered and should be investigated in a controlled clinical trial.

Aged

Oral lichenoid reactions related to mercury sensitivity.

Lichen planus is a common disorder of unknown aetiology. It has been proposed that in some cases it represents a form of allergic reaction to the metals contained in dental amalgam, particularly mercury. Twenty-nine consecutive dentate patients who had lichen planus of the oral mucosa were patch-tested to the range of metals contained in dental amalgam. Ten out of 29 (34%) showed an allergic reaction to mercury and all of these patients had amalgams greater than 5 years old. The amalgams were poorly contoured and had corroded, resulting in continued release of mercury ions. Six patients had their amalgams replaced with composite or glass ionomer materials resulting in resolution of ulcerated lesions. In a follow-up of 3-24 months, one patient had a recurrence of ulcerated areas and another, despite resolution of the oral lesions had persistent discomfort.

Adult

Skin reflectance measurements of patch test responses.

Skin reflectance values were used as an objective measure of skin haemoglobin content at patch test sites to facilitate quantification of the erythematous response to contact allergens in patients with allergic contact dermatitis. Reflectance measurements of patch test responses correlated well with the clinical scoring and provided a numerical measure of reaction severity. Experimental contact allergen formulations were also evaluated by this method.

Color

Oro-facial granulomatosis: a possible allergic basis.

Food or flavouring intolerance has been demonstrated in 14 out of 80 patients with oro-facial granulomatosis. Provoking molecules include cinnamaldehyde, carvone and piperitone, although a wide range of food or flavourings may be implicated. The nature of the reaction is not understood but does not seem to involve an IgE mediated response. At present the only reliable way of detecting specific provoking factors is by the use of an elimination diet.

Allergens

Tuberculoid leprosy.

The clinical features and management of a case of major tuberculoid leprosy presenting in the United Kindom are described. The possibility of encountering tropical disease in one's practice should be remembered.

Adult