SummaryIn order to obtain practical experience on the recognition, assessment and evaluation of discomfort in laboratory animals, the degree of discomfort was studied in gallstone-free and gallstone-bearing mice. Out of nine parameters to which scores were assigned per individual mouse, only the response to palpation of the right hypochondrium was found to score significantly higher in gallstone-bearing mice. That is, the incidence of squeaking and the magnitude of muscular contractions were significantly higher in these animals compared with the gallstonefree mice. The stance of the gallstone-bearing mice also tended to be abnormal, although the difference between gallstone-free and gallstonebearing animals did not reach statistical significance. Although this study does not prove unequivocally that the induction of gallstones per se causes discomfort or pain in mice, we tentatively conclude that it does. We feel that this should be taken into account in any projected work in which gallstone induction in animals may occur. There was considerable between-assessor variation in the assignment of scores to the variables used to assess discomfort, including the response to palpation. It is concluded that the selection of parameters and the experience and/or attitude of the assessor are critically important when the magnitude of discomfort, if any, is assessed in experimental animals.

A number of experiments was carried out to determine the sequence of events leading to death following administration of the euthanizing agent T61. Simultaneous recordings of the EMG, EEG, ECG and end-tidal CO2 (dogs only) were obtained in acutely instrumented rabbits and dogs. Results show that following T61 administration the loss of consciousness and loss of muscle activity occurred simultaneously. Vocalization and increased muscle movement occurred in the initial phase of the injection in 3 of 8 dogs, injected with T61 or butyramide. From this study it was concluded that the presence of the muscle relaxant does not pose an ethical problem for the use of T61 as an euthanizing agent, but our results suggest that the use of T61 may have some emotionally unpleasant side-effects.

9 Cases of endometriosis in rhesus monkeys were found in a colony of 35 females, which had undergone in the past X-ray treatment or one or more Caesarean sections and/or one or more treatments with gonadal steroids. Incidence, pathogenesis, clinical symptoms, histology and treatment are described.

SummaryAn attempt was made to assess discomfort in rats with hepatomegaly induced by feeding a high cholesterol, high cholate diet. After 8 weeks, the rats displayed a more than two-fold increase in liver weight when compared with controls fed a commercial diet. In a small open field test, behaviour of rats with hepatomegaly was similar to the controls. Of 9 parameters scored per rat, only the response to pressure on the right hypochondrium (tension of overlying muscles) scored higher than in control animals. There was considerable between-assessor variation in the assignment of scores. It is suggested, tentatively, that hepatomegaly in rats caused by cholesterol plus cholate feeding, may not cause extreme discomfort. Upon 'blind' palpation of control and test rats, an average of 60% of the rats with hepatomegaly were classified correctly.

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Chorionic gonadotropin (mCG) in serum and urine of monkeys was determined by a radioimmunoassay and hemagglutination inhibition (HAI subhuman primate tube test for pregnancy). HAI-positive pregnancy tests coincided fully with the mCG excretion patterns as determined by RIA (oLHβ system). The least reliable system was the hCG-β RIA. The HAI test allowed accurate prediction of the parturition date.