Comparative osteology and functional morphology of the forelimb of Cyonasua (Mammalia,Procyonidae), the first South American carnivoran

Extant procyonids only inhabit the Americas and are represented by six genera (Procyon, Nasua, Nasuella, Bassaricyon, Potos, and Bassariscus); all of them, except Bassariscus, are present in South America. The first records correspond to the early Miocene in North America (NA) and the late Miocene in South America (SA). Cyonasua was the first carnivoran to enter SA from NA, before the Great American Biotic Interchange, and went extinct in the early middle Pleistocene. This extinct procyonid is recorded in several localities of Argentina, and also in Venezuela. Paleobiological studies of procyonids are interesting from evolutionary and biogeographical viewpoints. In this study, the pectoral girdle and forelimb of 10 specimens of Cyonasua are described and compared with extant South American procyonids using a qualitative approach. Additionally, four functional morphology indexes were calculated for them and compared with an ecologically diverse sample of living carnivorans. Results indicate that Cyonasua most resembles Nasua nasua and Procyon cancrivorus, even though the extinct procyonid possessed peculiar features. Cyonasua had robust and relatively short forelimb bones, with strong stabilized joints, and movements associated with the sagittal plane, which suggest a tendency toward terrestrial habits, related to their ability to resist relatively high bending and shearing stresses. However, some features indicate a freedom in their range of movements, with moderate supination ability, compatible with climbing. When combined with previous analyses of dietary habits and estimated body mass, the morphology of Cyonasua would be well suited for digging and prey manipulation, allowing them to prey on small and relatively large-sized vertebrates, as well as to avoid some of the predators that were dominant in the Cenozoic of South America.     

Ultrastructural Features of Host-Parasite Relationship in Oral Candidiasis

In oral candidiasis, many keratinized epithelial cells and cells of Candida albicans are shed. Scales from patients with oral candidiasis were used for electron microscopic study of the epithelial-fungal relationship. Scales, scraped from the tongue and oral mucosa, were fixed for fungi. Electron microscopic observations showed cells of C. albicans outside, penetrating, or within the epithelial cells. Extracellular fungi possessed a floccular material adherent to the outer surface of the cell wall. Intracellular fungi lacked the floccular material which appeared to detach as fungi invaded the epithelial cells. Large vacuoles, which sometimes contained myelin figures, occupied the cytoplasm of fungal cells. Epithelial cells frequently contained several fungi. Discontinuous plasma membranes marked sites of fungal entry. Cytoplasmic areas devoid of fungi showed many tonofibrils, but the cytoplasm adjacent to fungi often lacked tonofibrils. Micrographs suggested that fungal cells lysed the tonofibrils. Bacteria were abundant in the scrapings, but always occupied an extracellular position.