Search

A 1-year-old, spayed, female, mixed-breed dog had two reddish-purple cutaneous lesions, one on the right dorsal antebrachium and the other on the right shoulder. The lesions consisted of approximately 13 x 3 cm and 15 x 10 cm, irregular, patchy regions of 0.5-3.0 cm, circular, sometimes raised, reddish-purple swellings resembling ecchymoses. The lesion on the antebrachium had been noticed since the dog was adopted at 6 months of age and appeared to have increased in size over an 11-week period, at which time skin punch biopsy revealed an infiltrative pattern of well-differentiated blood vessels leading to an interpretation that the lesion was a well-differentiated hemangiosarcoma. The second lesion was revealed when the dog had its fur shaved in that area during surgical preparation to excise the antebrachial lesion. No other skin lesions were found on the dog. Microscopically, there was a widely disseminated and infiltrative-like pattern of benign-appearing small blood vessels, which were throughout the superficial and deep dermis and subcutis. Although the disseminated nature suggested malignancy, the histologic appearance of well-differentiated small blood vessels and nonprogressive clinical features indicate that the lesions were benign. The dog has been followed for 6 years and to date has no evidence of progression of the antebrachial lesion or shoulder lesion. To the authors' knowledge, this is the first report of a congenital angiomatosis-like lesion in a young dog, with extensive involvement of the forelimb.

Abstract: The Auger electron emitter 123I was examined in the form of 4-[123I]iodoantipyrine and as [123I]NaI for its effectiveness in killing cells of different sensitivity to photon irradiation. Micronucleus assays showed that 4-[123I]iodoantipyrine is 2–3 times more effective in cell inactivation than [123I]NaI. This can be attributed to the fact that antipyrine, for reason of its lipid solubility, can enter cells and can reach the nucleus, whereas [123I]NaI is excluded from the cytoplasm. In the nucleus Auger decay is conceivably located on the DNA where it may invoke high-LET irradiation damage. Irradiation damage by [123I]NaI is by long range Auger and internal conversion electrons and hence less densely ionising. Results of the present study demonstrate, however, that the enhancement of micronuclei frequency (MNF) seen with 4-[123I]iodoantipyrine as compared to [123I]NaI is similar for all cell lines and that the ratio of 4-[123I]iodoantipyrine/[123I]NaI MN response remains the same. Experiments with the free radical scavenger DMSO, indicated nearly identical dose reduction factors for both 123I carriers. These two observations strongly suggest that the cell inactivation by 4-[123I]iodoantipyrine is not by direct high-LET ionisation of DNA, but is due to an indirect effect. The indirect radiation effect of Auger decay in the nucleus could arise because 4-[123I]iodoantipyrine is not incorporated into the DNA, but is only associated with chromatin where the DNA is shielded by histones.

Abstract:  The effects of sublethal concentrations of lead nitrate on the growth and reproduction of the African composting earthworm species, Eudrilus eugeniae, was studied by exposing worms in an organic substrate to lead-nitrate-contaminated food over a period of 76 days. The results revealed that growth was initially affected negatively by the presence of lead, while the maturation rate and cocoon production were not affected. In agreement with other studies on Eisenia fetida, cocoon viability was affected negatively by lead, making this a sensitive toxicity endpoint.

By using the method of Chapman-Enskog as a base, we have determined successive approximations of any order to the transport coefficients of shear viscosity and thermal conductivity for a monatomic ideal gas. The expressions for the transport coefficients involve only integrals which can be evaluated once the law of interaction between the spherically symmetrical particles is known. Moreover, we have developed a (13 + 9N)-field theory based on the method of Grad and showed that the transition from this theory to a five-field theory leads to the same results as those obtained through the method of Chapman-Enskog.

A method that combines the features of the methods of Chapman-Enskog and Grad is proposed to determine successive approximations to the transport coefficients. In this work it is applied to monatomic gases and mixtures.

Growth rate change in earthworms is considered to be a suitable endpoint when determining sublethal effects. In this study we evaluated growth and maturation in the vermicomposting earthworm speciesEudrilus eugeniae as marker of sublethal toxicity of copper and zinc. We also compared routes of uptake. Apart from exposing worms experimentally for 73 days to contaminated food, a series of contact filter paper tests was also performed to determine LD50 for copper and zinc. Both copper and zinc at sublethal concentrations affected growth and maturation in worms exposed to contaminated food. These worms had a copper content of 34.5 µg g-1 after 73 days and a zinc content of 184.9 µg g-1, showing a differential uptake. Copper was more toxic than zinc. Also in the contact test worms did take up more zinc than copper and the LD50 (48 h) for copper was 0.011 mg cm-2 and for zinc 0.066 mg cm-2, which translated to body burdens of 6 µg g-1 for copper and 131 µg g-1 for zinc. Indications were that a regulatory mechanism existed for both metals. Both metals were taken up through the body wall at a relatively fast rate. This study indicated that the skin was the major route of metal uptake. This study also showed a poor relation between the two types of tests for purposes of evaluating lethality of zinc and copper.

: A kinetic theory is developed for rarefied polyatomic gases of spherical and rough molecules with rotational energy in the presence of an external constant magnetic field. A method of solution of Boltzmann equation that combines features of the methods of Chapman-Enskog and Grad is used to determine transport coefficients that depend on the external magnetic field (Senftleben-Beenakker effect).