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F J Roe

Publications and source records attributed to F J Roe.

At least 19 recordsLinked to original sources
PubMed1991

Review of lead toxicology relevant to the safety assessment of lead acetate as a hair colouring.

The literature on lead toxicology has been critically reviewed to provide a safety assessment of lead acetate as a hair colouring. The main objectives were: (i) to determine the additional lead contribution from hair-colouring use to the total daily environmental lead intake; and (ii) to assess the toxicological significance of this additional contribution. The review also focuses attention on newer issues of concern over the effects of environmental lead on human health. Data available in animals and humans (including occupational exposure), mainly on lead acetate and other inorganic lead salts, have been presented and evaluated in respect of the following: absorption, distribution and excretion following ingestion; percutaneous absorption; carcinogenicity; genotoxicity; reproductive toxicity; neurological/behavioural status with particular reference to neuropsychological effects in children; and effects on other systems (e.g. cardiovascular). It is concluded that the absorption of lead from hair-colouring use represents about 0.5% of the lead absorption from the current average daily environmental lead intake. No convincing evidence could be found of any deleterious effect of current environmental lead levels on human health and thus the tiny contribution of lead acetate exposure from hair-colouring use can be regarded unequivocally as being toxicologically insignificant.

Animals↗
PubMed1991

Risks of premature death and cancer predicted by body weight in early adult life.

In a study of 30 months duration, involving 600 male and 600 female Wistar rats fed on 12 different diets/dietary regimes, none of which involved deliberate exposure to any known genotoxic carcinogen, highly significant between-group differences were observed in survival and incidence of various neoplastic and non-neoplastic diseases. A full report of the findings is being prepared. Here we report that, irrespective of diet or dietary regime, there were highly significant correlations of body weight at 29 weeks of age with premature death (P less than 0.0001 in both males and females), with development of benign or malignant neoplasm of any site (P less than 0.0001 in males and P less than 0.01 in females) and with development of malignant neoplasm at any site (P less than 0.0001 for sexes combined). Numerous kinds of neoplasm contributed to these overall correlations. The most significant were pituitary tumour (P less than 0.0001), mammary gland tumour (P less than 0.0001), squamous or anaplastic carcinoma of the jaw (P less than 0.001), and subcutaneous mesodermal tumours (P less than 0.05). The 20% of rats that were heaviest at 29 weeks were more than twice as likely to die prematurely than the lightest 20% (2.56 times--males, and 2.11 times--females), and almost twice as likely to develop a malignant tumour (1.87 times for the sexes combined). These findings have important implications for the design and interpretation of carcinogenicity tests in rodents and of laboratory and human studies of relationships between diet, ageing-related degenerative diseases, and cancer.

Animals↗
PubMed1979

Milky spots (Taches laiteuses) as structures which trap asbestos in mesothelial layers and their significance in the pathogenesis of mesothelial neoplasia.

The UICC standard sample of asbestos, crocidolite, was injected subcutaneously into the flanks of CBA/lac mice. Asbestos fibres were found in milky spots in the serosal cavities more than 442 days after the injection, in the form of either naked fibres or asbestos bodies. Milky spots were the only structure in which asbestos fibres were observed in the mesothelial layer. The fact that asbestos fibres were found in the liver, spleen, kidney, brain, etc., in addition to milky spots, suggested that they were transported by the blood stream throughout the body. This assumption was confirmed by the similar distribution of asbestos after intravenous administration. The vascular and cellular structure of milky spots is such that they are particularly likely to trap blood-borne asbestos fibres. Hyperplastic changes were observed in milky spots after both subcutaneous and intravenous administration of asbestos in mice. The possible involvement of milky spots in the genesis of tumors of the mesothelium following exposure of animals to asbestos is discussed.

Animals↗
PubMed1979

Atherogenesis in the White Carneau pigeon. Further studies of the role of carbon monoxide and dietary cholesterol.

Two experiments are described. In the first, 3 pairs of groups of 20 female White Carneau pigeons were fed on diets containing 0.5%, 1% or 2% cholesterol. Birds in one group from each pair were exposed to 150 ppm carbon monoxide (CO) for 6 h on 5 days of each week for 52 weeks, sufficient to raise their carboxyhaemoglobin (COHb) levels to approximately 10%, while those in the other group were sham-exposed under similar conditions. In the second experiment, 3 groups of 40 female pigeons were each fed on a diet containing 1% cholesterol, one group being exposed to CO to give COHb levels of 20%, one to give COHb levels of 10% and one being sham exposed. In addition, 20 birds in the second experiment were fed on the 1% cholesterol diet but were neither exposed to CO nor sham-exposed. Cholesterol enriched diets caused mean plasma cholesterol values in each group to rise sharply within 4 weeks of starting them, but the levels reached were as high with diets containing 0.5% cholesterol as for diets containing 1% or 2% added cholesterol. Exposure to CO increased plasma and aortic cholesterol levels, though this increase was only statistically significant for aortic levels in the second experiment. In both experiments combined exposure to the 1% cholesterol diet and CO resulted in a significant decrease in aortic triglyceride content. The incidence and severity of coronary artery atherosclerosis was associated with increasing dietary cholesterol. It was also associated with exposure to CO in birds given 0.5% or 1%, but not 2%, dietary cholesterol; the increase in birds given 1% was related to the dose of CO. Possible mechanisms are discussed for this effect of CO, which is not found in normally fed birds.

Animals↗
PubMed1979

Food and cancer.

There are good reasons to suspect that the quantity and quality of food influence both the overall risk of development of many forms of cancer and the types of cancer which occur most commonly. The evidence is briefly reviewed and the kinds of mechanisms that may be responsible listed. The striking effects of dietary restriction on cancer risk in laboratory rats and mice and the possibility that dietary restraint may be beneficial in man are discussed. Recent laboratory evidence that carcinogens may be formed in food during cooking is mentioned. Finally, the importance of avoiding mineral imbalance when conducting animal studies designed to evaluate the safety of food constituents and additives is stressed in relation to urinary-calculus formation and bladder-tumour risk.

Animal Nutritional Physiological Phenomena↗
PubMed1978

Squamous lesions in lungs of rats exposed to tobacco-smoke-condensate fractions by repeated intratracheal instillation.

Twice-weekly intratracheal instillations in rats of up to 24 mg of Fraction (R + P)G suspended in either infusine (I) or buffered saline/gelatine (BS/G) gave rise to foci of squamous metaplasia of alveolar epithelium (SqM) and squamous neoplasms (SqN). Fraction (R + P)G, which is a fraction of cigarette-smoke condensate almost as tumorigenic for mouse skin as the nearly 30 × larger mass of condensate from which it is derived, could be given in this way for up to 40 weeks without excessive mortality or any marked effect on the rate of body-weight gain. By contrast, similar treatment with Fraction N(QG), a fraction having very low tumorigenic activity for mouse skin, induced no SqN and barely any excess of SqM over that induced by either vehicle alone.The effects of Fraction (R + P)G on the incidence of SqM and SqN were both time and dose related, the effect on SqM incidence being already evident after 10 weeks of treatment. No SqN seen were unequivocally malignant, though, due to the design of the experiment, only 5 rats exposed to Fraction (R + P)G were observed more than 60 weeks after the start of the experiment.Other changes in the lung, including aggregates of alveolar macrophages laden with golden-brown pigment (GBM) and foci of cuboidal/columnar metaplasia of alveolar epithelium (CCM), were frequently seen in response to both fractions. Fraction (R + P)G administered in I was more effective in causing SqM and SqN than the same fraction administered in BS/G. The implications of the findings are discussed, particularly the possibility that the intratracheal/instillation technique might be useful as a rapid bioassay for comparing the tumorigenicity of different cigarette-smoke condensates.

Animals↗
PubMed1978

Hydrazine.

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Adult↗