We found that SpO values decreased to about 80% in the ketamine/xylazine/atropine protocol and fell just below 90% in the alphaxalone protocol. We observed a clear decrease in PaO values under the anesthetized condition compared to the awake condition. Our data indicate that single-shot anesthesia may cause hypoxemia in marmosets. Previous studies on other non-human primate have reported no SpO decrease and hypoxemia; thus, our experiment suggests that marmosets may have a more fragile respiratory system and require intensive veterinary care during anesthesia.

To our knowledge, this is the first case report of HCC with intracranial metastasis in a macaque.

Marmoset wasting syndrome (MWS) is clinically characterized by progressive weight loss. Although morbidity and mortality of MWS are relatively high in captive marmosets, its causes remain unknown. Lipid mediators are bioactive metabolites which are produced from polyunsaturated fatty acids, such as arachidonic acid (AA) and eicosapentaenoic acid. These lipid metabolites regulate a wide range of inflammatory responses and they are excreted into the urine. As urinary lipid profiles reflect systemic inflammatory conditions, we comprehensively measured the levels of 141 types of lipid metabolites in the urines obtained from healthy common marmoset (Callithrix jacchus) (N = 7) or marmosets with MWS (N = 7). We found that 41 types of metabolites were detected in all urine samples of both groups. Among them, AA-derived metabolites accounted for 63% (26/41 types) of all detected metabolites. Notably, the levels of AA-derived prostaglandin (PG) E 2 , PGF 2α , thromboxane (TX) B 2 and F 2-isoprostanes significantly increased in the urine samples of marmosets with MWS. In this study, we found some urinary lipid metabolites which may be involved in the development of MWS. Although the cause of MWS remains unclear, our findings may provide some insight into understanding the mechanisms of development of MWS.

Common marmosets (Callithrix jacchus) are increasingly used in biomedical research, 1 particularly since the successful generation of transgenic marmosets. 2 While they are often anaesthetised for various procedures, published information on marmoset anaesthesia and analgesia is limited. 3-7 Inhalation anaesthetics are preferred for both shorter and longer procedures. However, there are some occasions when inhalation anaesthetics are not feasible, for example anaesthesia in the field, in the enclosure or in the home cage. Injectable anaesthetics may be considered as alternatives and even preferred under such conditions. Alfaxalone is a neuroactive steroid, activating gamma aminobutyric acid (GABA) receptors resulting in anaesthetic effects. 8