Graham Chester

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Predictions of human pesticide metabolism which are needed for the interpretation of biological monitoring data are frequently made from animal studies. Consequently, assumptions have to be made about the relationship between absorbed dose and metabolite excretion. The results from two human volunteer studies highlight the problems associated with(More)
Passive dosimetry (PD) methods for measuring and estimating exposure to agricultural workers (i.e., persons handling agricultural chemicals and working in treated crops) have been in use since the 1950s. A large number of studies were conducted in the 1950s through 1970s to characterize exposure. Since the 1980s quantitative dermal PD methods are used in(More)
Icon 10 WP insecticide, a wettable powder formulation containing 10% lambda-cyhalothrin, was evaluated for possible adverse effects on the health of spraymen and villagers during treatment of dwellings for malaria vector control. Skin sensory effects and occasional coughing and sneezing in confined spaces were the only symptoms noted by the workers(More)
In 200 cases of retinal detachment successfully treated without drainage of subretinal fluid complete reattachment of the retina was achieved in the first postoperative week in 76 per cent of cases. Delay in subretinal fluid absorption in the remaining 24 per cent of cases was directly related to the duration of the retinal detachment but was not influenced(More)
A massive dose of 7.5 g of 4,4'-diamino, diphenyl sulphone (dapsone) taken as a suicide attempt in a patient on long-term therapy for tuberculoid leprosy resulted in permanent bilateral retinal necrosis, previously unreported side effect of this drug. The patient developed a severe haemolytic anaemia, methaemoglobinaemia, and acute renal failure requiring(More)
Absorption of the herbicide paraquat (1,1'-dimethyl-4,4'-bipyridinium) by mixer-loaders and spray operators on a Sri Lankan tea plantation was assessed over five consecutive days of spraying. Beginning on the day before spraying started and continuing for each of the five spraying days and for seven days after the last day of spraying, 24-hour urine samples(More)
Studies carried out on the occupational exposure to paraquat of plantation workers in Malaysia comprised quantitative estimates of dermal and respiratory exposure of knapsack spray operators, carriers, and rubber tappers operating under their normal working conditions. Spray operators have been shown to be dermally exposed to paraquat by walking through(More)
  • G Chester
  • 1993
The evaluation of the occupational exposure of agricultural workers to pesticides is an integral part of the risk assessment for product safety and regulatory purposes. At present, there is no internationally accepted, harmonized approach to this exposure evaluation. This paper reviews the currently available methods for the measurement of exposure to, and(More)
This paper describes a simplified technique for biopsy of the retina and choroid which had been used in 5 human volunteers. The biopsy was carried out in 4 immediately before enucleation of an eye for malignant melanoma and in 1 patient who was undergoing trabeculectomy for painful glaucoma associated with retinitis pigmentosa. A combination of intravenous(More)
Epidemiologic studies frequently show associations between self-reported use of specific pesticides and human cancers. These findings have engendered debate largely on methodologic grounds. However, biologic plausibility is a more fundamental issue that has received only superficial attention. The purpose of this commentary is to review briefly the(More)