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883. Will no one crack this egg?
672
CANCER RESEARCH
observed in macrophage monolayers prepared from alveolar washings: cultured cells from healthy rats were homogeneous, whereas diseased rats gave rise to a heterogeneous mixture of ceils, mis-shapen macrophages containing debris and many lymphocytes. It is suggested that alveolar washings will reveal the presence of lymphocytic infiltration even when the initial viral lesions are small and incipient. The authors conclude that the presence of disease in a rat colony is associated with distinct changes in the blood picture. Experimental work requiring haematological observations should, therefore, be adequately controlled and a high standard of husbandry practised, using preferably animals of SPF origin. Existing "normal" standards for the rat should be disregarded since they were probably established on diseased animals. Fresh baseline values should be assessed for new colonies as outlined above.
CANCER RESEARCH 883. Will no one crack this egg?
Szepsenwol, J. (1965). The carcinogenic effect of egg yolk in mice of the C57 BI. strain. Proc. Am. Ass. Cancer Res. 6, 63. We previously referred to what was tantamount to the complete lack of interest in establishing the significance of carcinogenicity studies on egg extracts (Cited in F.C.T. 1965, 3, 538) which have now been in progress for over a decade (Cited in F.C.T. 1964, 2, 66). The latest report by the present author deals with the carcinogenic effect of raw egg yolk on mice of the C57BL strain. We sincerely hope that food faddists will be horrified to learn that 1 egg yolk shared daily between 10-20 mice proved lethal within 1-3 months. When smaller quantities (1 egg yolk/50 mice/day) were given to parent mice and their offspring, the 120 mice survived an average of 660 days and 74.1% of them developed malignancies; lymphosarcomas, lung adenocarcinomas and hepatomas predominating. Out of the 104 control mice placed on the same basic diet, only 15 animals (14.4%) developed malignancies, mainly lyphosarcoma and a few lung adenocarcinomas. The author concludes that mice of the C57BL strain are as sensitive to this egg regime as the T.M. strain. [For man, the equivalent intake of egg yolks used in the above carcinogenicity study would be about 10/day. Assuming that man consumes 1 egg/day a very small margin of safety (less than 10-fold) would appear to operate. While there has been no suggestion so far that egg consumption in man constitutes a carcinogenic hazard, what is urgently needed is a quick and adequate solution to this problem. It is most surprising that the so-called prophets of doom in the cancer field have yet to pronounce the dire warnings and sweeping assertions that we have grown accustomed to. Perhaps they are learning fast !]
CANCER RESEARCH
observed in macrophage monolayers prepared from alveolar washings: cultured cells from healthy rats were homogeneous, whereas diseased rats gave rise to a heterogeneous mixture of ceils, mis-shapen macrophages containing debris and many lymphocytes. It is suggested that alveolar washings will reveal the presence of lymphocytic infiltration even when the initial viral lesions are small and incipient. The authors conclude that the presence of disease in a rat colony is associated with distinct changes in the blood picture. Experimental work requiring haematological observations should, therefore, be adequately controlled and a high standard of husbandry practised, using preferably animals of SPF origin. Existing "normal" standards for the rat should be disregarded since they were probably established on diseased animals. Fresh baseline values should be assessed for new colonies as outlined above.
CANCER RESEARCH 883. Will no one crack this egg?
Szepsenwol, J. (1965). The carcinogenic effect of egg yolk in mice of the C57 BI. strain. Proc. Am. Ass. Cancer Res. 6, 63. We previously referred to what was tantamount to the complete lack of interest in establishing the significance of carcinogenicity studies on egg extracts (Cited in F.C.T. 1965, 3, 538) which have now been in progress for over a decade (Cited in F.C.T. 1964, 2, 66). The latest report by the present author deals with the carcinogenic effect of raw egg yolk on mice of the C57BL strain. We sincerely hope that food faddists will be horrified to learn that 1 egg yolk shared daily between 10-20 mice proved lethal within 1-3 months. When smaller quantities (1 egg yolk/50 mice/day) were given to parent mice and their offspring, the 120 mice survived an average of 660 days and 74.1% of them developed malignancies; lymphosarcomas, lung adenocarcinomas and hepatomas predominating. Out of the 104 control mice placed on the same basic diet, only 15 animals (14.4%) developed malignancies, mainly lyphosarcoma and a few lung adenocarcinomas. The author concludes that mice of the C57BL strain are as sensitive to this egg regime as the T.M. strain. [For man, the equivalent intake of egg yolks used in the above carcinogenicity study would be about 10/day. Assuming that man consumes 1 egg/day a very small margin of safety (less than 10-fold) would appear to operate. While there has been no suggestion so far that egg consumption in man constitutes a carcinogenic hazard, what is urgently needed is a quick and adequate solution to this problem. It is most surprising that the so-called prophets of doom in the cancer field have yet to pronounce the dire warnings and sweeping assertions that we have grown accustomed to. Perhaps they are learning fast !]