Influence of carbon tetrachloride on induction of tumours of the liver and kidneys in mice by netrosamines.

Mice were given a single dose of nitrosolimethylamine, nitrosoliethylamine or nitrosomethylethylamine and the yield of tumours and related lesions in the livers determined 12 months later. A hepatonecrotic dose of CCl4 24 or 48 h before the nitrosamines, increased the yields of hepatocellular tumours and proliferative foci in the livers, whereas when given 60 h before the nitrosamines there was no significant effect

Tumour Formation in Mice by Urethane Administered With Related Carbamates

A tumour initiating dose of ethyl carbamate was administered to mice by subcutaneous injection together with a dose of one of the homologous esters or an ethyl N-alkyl derivative. The homologues used were the methyl, n-propyl and n-butyl esters, and the derivatives were the N-methyl, N-ethyl and N-n-propyl ethyl esters. The mice were then given promoting treatment with croton oil for 28 weeks

Osculating orbits in Schwarzschild spacetime, with an application to extreme mass-ratio inspirals

We present a method to integrate the equations of motion that govern bound, accelerated orbits in Schwarzschild spacetime. At each instant the true worldline is assumed to lie tangent to a reference geodesic, called an osculating orbit, such that the worldline evolves smoothly from one such geodesic to the next. Because a geodesic is uniquely identified by a set of constant orbital elements, the transition between osculating orbits corresponds to an evolution of the elements. In this paper we derive the evolution equations for a convenient set of orbital elements, assuming that the force acts only within the orbital plane; this is the only restriction that we impose on the formalism, and we do not assume that the force must be small. As an application of our method, we analyze the relative motion of two massive bodies, assuming that one body is much smaller than the other. Using the hybrid Schwarzschild/post-Newtonian equations of motion formulated by Kidder, Will, and Wiseman, we treat the unperturbed motion as geodesic in a Schwarzschild spacetime whose mass parameter is equal to the system's total mass. The force then consists of terms that depend on the system's reduced mass. We highlight the importance of conservative terms in this force, which cause significant long-term changes in the time-dependence and phase of the relative orbit. From our results we infer some general limitations of the radiative approximation to the gravitational self-force, which uses only the dissipative terms in the force.Comment: 18 pages, 6 figures, final version to be published in Physical Review

Partial hepatectomy and toxicity of dimethyl-nitrosamine and carbon tetrachloride, in relation to the carcinogenic action of dimethylnitrosamine.

The yield of tumours in the liver of rats was increased when dimethylnitrosamine was given 1, 6 or 12 h after partial hepatectomy and still further increased if it was given after an interval of 24-72 h. The increase was greater after two-thirds than after one-third hepatectomy. An increase in the number of kidney tumours was also found. Microsomal DMN-demethylase activity was depressed after partial hepatectomy for up to 6 days in mice and rats. The LD50 of DMN on the other hand was decreased for 3 days, after which it returned to normal. The extent of liver necrosis produced by DMN was increased at 6 and 24 h after partial hepatectomy but was within the usual range at longer intervals. These results suggest that prolonged exposure of the tissues to DMN after partial hepatectomy played a significant role in the development of liver tumours as well as those in the kidney, in addition to the role of regeneration of the liver, and that the relative roles were still to be elucidated