Biomedical subjects

T J Fallon

Publications and source records attributed to T J Fallon.

3 recordsLinked to original sources

PubMed1991

Oxidative effects of laser photocoagulation.

Diabetic proliferative retinopathy is a common and sight-threatening condition. Oxidative stress is an integral and possibly causative part of the pathogenesis. Although laser photocoagulation is usually a beneficial treatment it remains unclear how it works. The possibility that it induces a sudden, temporary increase in free radical activity either by direct thermal damage or by oxygen reperfusion is explored in this clinical study by measuring the oxidative status in the peripheral blood of 13 patients undergoing panretinal photocoagulation. There were significant increases at one hour in malondialdehyde-like material (MDA-LM), 8.1 (6.9-9.6) nmol/mL, to 9.1 (7.6-9.8) nmol/mL, (less than 0.005); plasma thiols (PSH), 423 (352-457) microns/L, to 444 (382-478) microns/L, (p less than 0.005) and red cell reduced glutathione (GSH), 1357 (1295-1655) microns/L, to 1480 (1305-1760) microns/L, (p less than 0.01). Diene conjugates rose over the first hour 0.55 (0.36-0.79) od/mL, to 0.58 (0.34-0.85) od/mL falling to 0.56 (0.36-0.79) od/mL at 2 h but these changes were not significant. At 2 h, MDA-LM 8.4 (6.7-9.6) nmol/mL and PSH 404 (379-462) microns/L had returned to baseline but GSH remained significantly elevated 1500 (1325-1675) microns/L, (p less than 0.005 compared to baseline). This is a new observation and in some circumstances such generation of free radicals could explain the mechanism behind the complications of photocoagulation by direct or indirect damage to vascular endothelium leading to increased vascular permeability manifest as macular oedema or choroidal effusions.

Adult↗

PubMed1987

Long-term follow-up of patients who underwent yttrium-90 pituitary implantation for treatment of proliferative diabetic retinopathy.

Between 1960 and 1976 117 patients underwent pituitary implantation with yttrium-90 (90Y) for treatment of proliferative retinopathy at the Hammersmith Hospital, London. Mean age at operation was 35 +/- 11 years (mean +/- SD), and mean duration of diabetes 18.6 +/- 10.0 years. Mean insulin dosage prior to implant was 67.2 +/- 24 units, falling to 30.4 +/- 14.9 units post-implant. Thirty-two per cent of patients are still living, 60% are deceased and 8% are lost to follow-up. The 5-year survival rate was 82%. Of the causes of death, 21% died of infection, adrenal insufficiency or hypoglycaemia, 12% of renal failure, and 47% of myocardial or cerebral vascular disease. Ophthalmological follow-up was carried out on the 100 patients operated on between 1965 and 1976. The mean age of this group at implant was 35 +/- 10.5 years, and mean duration of diabetes 17.2 +/- 8.7 years. Visual acuity in the better eye at operation was 6/12 or better in 84% of patients, and this percentage remained similar at the time of the 5 and 10 year follow-up. Blindness (6/60 or worse) in both eyes was present in 12% of patients at the time of 5 and 10 year assessments. By 5 years new vessels on the disc had improved from a mean grading of 2.7 +/- 1.6 to 0.8 +/- 1.2 (p less than 0.001), and by 10 years there was no disc neovascularisation in any eye. There was a similar improvement in the grading of hard exudates, microaneurysms and haemorrhages, but there was an increase in fibrous retinitis proliferans.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1976

Errors in EMG reporting.

In a review of 112 electromyographic reports from 112 different electromyographers, errors were classified as anatomic, terminologic, technical and interpretative. Ninety-seven of the reports had substantive errors. The EMG report should be complete, precise, accurate and logical and include a summary of the anatomic and neurophysiologic data with a translation into a probable clinical diagnosis.

Diagnostic Errors↗