Effects of Ehrlichia phagocytophila infection on serum thyroid hormone concentrations and on antipyrine clearance and metabolite formation in dwarf goats.

The influence of infection with Ehrlichia phagocytophila (EP) on serum thyroid hormone concentrations and on antipyrine (25 mg/kg of body weight, IV) plasma elimination and urinary metabolite excretion was studied in castrated male dwarf goats. Mean thyroid hormone concentrations moderately decreased in EP-infected goats, with maximal decrease in total and free triiodothyronine and thyroxine serum concentrations of 56, 64, 23, and 19%, respectively. The estimated pharmacokinetic values of antipyrine (AP) in EP-infected goats were similar to those in the goats when healthy. However, glucuronidation of the AP-metabolites 3-hydroxymethyl-AP, 4,4'-dihydroxy-AP, and 4-hydroxy-AP was reduced during the febrile episode of the acute-phase response to EP infection.     

Variance decomposition in the estimation of genetic variance with selected data.

Estimation of genetic variance in populations under selection involves assumptions on base animals. Base animals are often considered unselected and it also has been proposed to treat selected base animals as fixed. The consequences of assumptions on base animals in the estimation of genetic variance in selected populations are not fully understood. Variance decompositions are introduced for simple designs to quantify the differences between models that treat base animals in different ways. Independent contrasts were constructed and REML estimates of variance components were compared for different designs and selection rules. The method shows how selection is accounted for in a complete model and why estimation of variance components can become biased when base animals are treated as fixed.     

Quantitative structure-activity relationships of the inhibition of photosynthetic electron flow by substituted diphenyl ethers

The effect of 41 substituted diphenyl ethers (derivatives of nitrofen and chloroxuron) on photosynthesis in isolated spinach chloroplasts has been studied. All the chemicals were found to be inhibitors of non-cyclic electron transport; the pI₅₀ values varied from 3.17 to 7.16 (I₅₀ is the molar concentration causing 50% inhibition; pI₅₀= -log I₅₀). Based on their structures, the compounds were divided into four groups; for most groups, a correlation between the inhibition of photosynthesis and physicochemical parameters was found. Lipophilicity proved to be the most important parameter; electronic effects did not play a role. Introduction of substituents into the nitrophenyl ring of nitrofen lowered activity considerably. Nitrofen and and chloroxuron analogues seemed to inhibit at different sites in the electron transport chain. A relationship between inhibition of photosynthesis and herbicidal activity was not clear.     

Studies on the influence of non-steroidal anti-inflammatory drugs upon trypanosomiasis in goats and sheep

The non-steroidal anti-inflammatory drug (NSAID) flurbiprofen caused a rise in parasitaemia in goats infected with Trypanosoma vivax, Trypanosoma congolense and Trypanosoma brucei. All trypanosome-infected goats treated with flurbiprofen showed many dividing trypanosomes. This also included the short-stumpy forms of T. brucei. In T. vivax-infected goats flurbiprofen treatment resulted in 100% mortality in the acute and chronic stages of the infection. The increase in parasitaemia of T. brucei infected goats, treated with flurbiprofen, was not associated with an increase in mortality. The increase in parasitaemia of T. congolense-infected goats, treated with flurbiprofen, tended to be associated with a somewhat higher mortality but this was statistically not significant. The significant rise in parasitaemia could be reproduced in T. brucei-infected sheep without, however, killing the animals. Two other NSAIDs were also studied. Suprofen caused a rise in parasitaemia and 100% mortality when given to goats in the acute stage of T. vivax infection. Results with flunixin meglumine, when tested in T. brucei infected goats, were not conclusive.