Carnivorans are a diverse group of mammals that includes carnivorous, omnivorous and herbivorous, domesticated and wild species, with a large range of brain sizes. Carnivory is one of several factors expected to be cognitively demanding for carnivorans due to a requirement to outsmart larger prey. On the other hand, large carnivoran species have high hunting costs and unreliable feeding patterns, which, given the high metabolic cost of brain neurons, might put them at risk of metabolic constraints regarding how many brain neurons they can afford, especially in the cerebral cortex. For a given cortical size, do carnivoran species have more cortical neurons than the herbivorous species they prey upon? We find they do not; carnivorans (cat, mongoose, dog, hyena, lion) share with non-primates, including artiodactyls (the typical prey of large carnivorans), roughly the same relationship between cortical mass and number of neurons, which suggests that carnivorans are subject to the same evolutionary scaling rules as other non-primate clades. However, there are a few important exceptions. Carnivorans stand out in that the usual relationship between larger body, larger cortical mass and larger number of cortical neurons only applies to small and medium-sized species, and not beyond dogs: we find that the golden retriever dog has more cortical neurons than the striped hyena, African lion and even brown bear, even though the latter species have up to three times larger cortices than dogs. Remarkably, the brown bear cerebral cortex, the largest examined, only has as many neurons as the ten times smaller cat cerebral cortex, although it does have the expected ten times as many non-neuronal cells in the cerebral cortex compared to the cat. We also find that raccoons have dog-like numbers of neurons in their cat-sized brain, which makes them comparable to primates in neuronal density. Comparison of domestic and wild species suggests that the neuronal composition of carnivoran brains is not affected by domestication. Instead, large carnivorans appear to be particularly vulnerable to metabolic constraints that impose a trade-off between body size and number of cortical neurons.

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ResumoO conhecimento das variações nos vasos renais possui importância em um programa de sistematização da anatomia radiológica e cirúrgica, tanto para o homem quanto para animais destinados a pesquisa, ensino e treinamento cirúrgico. As artérias renais têm sido estudas tanto radiograficamente quanto através de dissecção. Atenção particular é dada ao estudo desses vasos enfatizando as variações entre as diferentes espécies animais. O local de origem das artérias renais a partir da aorta abdominal varia de acordo com a topografia renal nos diferentes animais. A artéria renal direita se origina mais cranialmente que a esquerda de acordo com a posição mais cranial do rim direito. O objetivo deste artigo é descrever um caso de dupla artéria renal esquerda originando-se da superfície ventral da artéria aorta abdominal em um cadáver de gato macho com três anos de idade. O mesmo foi fixado e preservado com solução de formaldeído a 10% e teve o seu sistema arterial preenchido com látex corado. Observou-se que o rim esquerdo foi suprido por duas artérias renais, de diferente topografia e arranjo, caracterizando duplicidade da artéria renal. Palavras-chave: Duplicidade, artéria renal, gato AbstractKnowledge of the renal vessels variations has importance in a systematization program of radiological and surgical anatomy, both in humans and animals, applied for research and surgical training. Renal arteries have been considered by dissective or angiographic study means. Particular attention has been paid to the study of these vessels, outlining the variations noticed among various animal species. The renal arteries sites of origin of the abdominal aorta vary according to the renal topography of the different animals. As a rule, the right artery arises more cranially than the left one, according with the most cranial position of the right kidney. Thus, the goal of this article is to describe a case of a left double renal artery originating from the ventral portion of the aorta, in a three old male cat cadaver, formalin-preserved at 10% and with latex colored vascular injection. It was observed that the left kidney was supplied by two arteries of different topography and arrangements, showing duplicity of the renal artery.

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Poly(lactic acid) (PLA)-containing nerve guidance conduits (NGCs) are currently being investigated for nerve repair as an alternative to autograft, which leads to permanent functional impairment in the territory innervated by the removed nerve. Combination of polymers modifies the physical properties of the conduits, altering their nerve-guidance properties. Conduits made from PLA-only or combined with other polymers have been used successfully for nerve repair, but their efficiency has not been compared. We compared the morphological and functional outcomes of peripheral nerve repair by using NGCs made of poly(lactic acid) and combined or not with polycaprolactone (PLA/PCL) or polyvinylpyrrolidone (PLA/PVP). To assess the functional recovery, we employed a mechanical hyperalgesia analysis, sciatic functional index (SFI), and electroneuromyography. The mechanical hyperalgesia analysis showed that the PLA group improved more rapidly than the PLA/PVP and PLA/PCL groups; similarly, in the electroneuromyography assay, the PLA group exhibited higher amplitude than the PLA/PCL and PLA/PVP groups. However, the SFI improvement rates did not differ among the groups. Morphologically, the PLA group showed more vascularization, while the nerve fiber regeneration did not differ among the groups. In conclusion, the PLA-only conduits were superior to the other NGCs tested for nerve repair.