Comparison of Dust Retention in Specific Pathogen Free and Standard Rats

Morris, T. G.; Roberts, W.H.; Silverton, R.E.; Skidmore, J. W.; Wagner, J. C.; Cook, Graeme

doi:10.1016/b978-1-4832-1329-3.50025-1

Cited by 8 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The uptake of amosite dust deep into the lungs of normal and SPF rats has been shown to be three times greater than the uptake of chrysotile dust (Wagner and Skidmore, 1965;Morris et al, 1967) Differential deposition was only minimally involved, as the subsequent clearance rate of chrysotile was some three times faster than that ofamosite. Holt et al (1966) found no chrysotile and only few amphibole fibres in the lymph nodes of exposed guinea pigs, which suggests that clearance occurs mainly via the respiratory tract.…”

Section: Discussionmentioning

confidence: 96%

Experimental asbestosis: an investigation of functional and pathological disturbances. II. Results for chrysolite and amosite exposure

Hiett

1978

Occupational and Environmental Medicine

View full text Add to dashboard Cite

Long-term studies of respiratory function and lung morphology were carried out on control groups of guinea pigs and matched groups exposed by inhalation to asbestos dust. Animals were exposed to aerosols of chrysotile or amosite asbestos containing large numbers of short fibres, for either 9 or 18 days. Resistance and dynamic compliance of the guinea pig respiratory system were measured non-destructively, while the point counting technique was applied to the histological preparations. Under these exposure conditions the extent of pathological and functional changes were not related to differences in duration of exposure. Such changes were more marked, however, in animals exposed at eight rather than three months of age. The measurement of dynamic compliance provided the most sensitive assessment of the functional disturbances, which were more extensive following chrysotile exposure. Progressive peribronchiolar fibrosis developed about 40 weeks after chrysotile exposure at eight months of age, but not until about 70 weeks for animals exposed when three months old. No fibrotic reaction was seen during the 70 weeks of the amosite experiments. The relationships between pathological and functional changes throughout these experiments are discussed, and explanations for the apparent differences in fibrogenicity between chrysotile and amosite are suggested. Early detection of asbestosis may be aided by use of lung function tests known to be sensitive to small airways disease. MethodsThe experimental methods and the maintenance of animals were described in Part I (British Journal of Industrial Medicine, 1978, 35, 129-134

show abstract

Section: Discussionmentioning

confidence: 96%

Experimental asbestosis: an investigation of functional and pathological disturbances. II. Results for chrysolite and amosite exposure

Hiett

1978

Occupational and Environmental Medicine

View full text Add to dashboard Cite

show abstract

“…A few rats had multiple malignant tumours: 2 of the rats with mesothelioma of the pleura also had a lung carcinoma and one rat with a squamous carcinoma The amount of chrysotile retained in the lungs did not show any clear increase with dose in rats exposed for longer than 3 months. In two earlier experiments (Wagner and Skidmore, 1965;Morris et al, 1967) a higher airborne dust concentration was used to give a cumulative dose in 6 weeks similar to that given in the present experiment over 3 months. The weight of asbestos found in the lungs of rats exposed to amphibole was 3 times greater than in those exposed to chrysotile.…”

Section: Asbestosismentioning

confidence: 90%

“…This method was used in previous experiments (Morris et al, 1967). After exposure the rats were caged in threes or fours isolated in a special unit supplied with filtered air.…”

Section: Materials Ani) Methodsmentioning

confidence: 99%

The Effects of the Inhalation of Asbestos in Rats

Wagner¹,

Berry²,

Skidmore³

et al. 1974

Br J Cancer

486

199

View full text Add to dashboard Cite

Summary.-Two experiments in which SPF Wistar rats were exposed by inhalation to dust clouds of the UICC standard reference samples for periods of between one day and 2 years are described. All the samples of asbestos produced asbestosis which continued to progress after removal from exposure but only a little fibrosis was observed in control rats. Lung tumours, ranging in severity from adenomata to squamous carcinomata, were produced by all samples but in the controls there were only a few adenomata and none of the more serious tumours. Of the 20 tumours which metastasized, 16 occurred after exposure to one or other of the 2 chrysotile samples. In addition, a total of 11 mesotheliomata occurred, 4 of which were with crocidolite and 4 with Canadian chrysotile. Two of the mesotheliomata occurred with only one day's exposure to asbestos. There was a positive association between asbestosis and lung tumours.WAGNER, Berry and Timbrell (1973) reported the results of experiments in which rats were inoculated intrapleurally with samples of asbestos. In the discussion it was mentioned that two experiments in which rats had been exposed to dust clouds of the UICC reference samples had been carried out, and the results of these are now presented. Some preliminary results of one of these experiments were reported by Wagner (1972).In both experiments the rats were exposed to similar dust concentrations and the dose varied by exposing rats for various lengths of time. The main aim was to establish the relationship between the development of malignant tumours in the lungs and the dose and type of asbestos dust but, additionally, the amount of fibrosis was assessed. MATERIALS ANI) METHODSCaesarean derived rats of the Wistar strain were used which had been bred at the Unit from SPF stocks given to us by the Imperial Chemical Industries, Pharmaceutical Division at Alderley Edge, Cheshire in 1964 and 1968.The asbestos samples used consisted of the 5 UICC standard reference samples (Timbrell, Gilson and Webster, 1968) which were prepared following recommendations of the UICC. These samples are of 3 amphibole types amosite, anthophyllite and crocidolite-and 2 chrysotiles-a Canadian and a Rhodesian sample.The rats were exposed in 1e4 m3 inhalation chambers (Timbrell et al., 1970) which contained 8 cages, each of which could hold 6 rats, or, for a short period with young rats, there was room for a seventh. Five chambers were used, one for each type of asbestos. The chambers were constructed so that the rats could be tended without the chambers being opened.The dust clouds were generated using a specially devised dispenser (Timbrell, Hyett and Skidmore, 1968). The clouds were generated for 7 hours a day and 5 days per week. The respirable dust concentrations were measured using size selective gravimetric dust samples (Cassella Type 114A). The collected samples were evaluated at the end of each daily session. In order to achieve the required dosage, calculated as the product of concentration and time, variations occurring in the concentr...

show abstract

“…The present results indicat,e that the dissolution of silica fl10m the amosite sample was faster than that from quartz at 37°C. Morris et al (8) observed that the eliminatiom. rates of amosite and silica from rat lung…”

Section: Discussionmentioning

confidence: 99%

Dissolution of silicic acid from amosite and quartz dusts under physiological conditions.

Rahman¹,

Beg²,

Viswanathan³

1975

Scand J Work Environ Health

View full text Add to dashboard Cite

, Q., BEG, M. U. and VISWANATHAN, P. N. Dissolution of silicic acid from amosite and quartz dusts under physiological conditions. Scand. j. work environ. & health 1 (1975) 117-119. The dissolution of silica from amosite dust in human serum and in Ringer buffer at 37°C was found to be significantly higher than that from quartz. The significance of this finding in relation to their fibrogenic effects has been discussed.

show abstract

Comparison of Dust Retention in Specific Pathogen Free and Standard Rats

Cited by 8 publications

References 4 publications

Experimental asbestosis: an investigation of functional and pathological disturbances. II. Results for chrysolite and amosite exposure

Experimental asbestosis: an investigation of functional and pathological disturbances. II. Results for chrysolite and amosite exposure

The Effects of the Inhalation of Asbestos in Rats

Dissolution of silicic acid from amosite and quartz dusts under physiological conditions.

Contact Info

Product

Resources

About