Pulmonary alveolar proteinosis (PAP) is a disease of surfactant clearance in which functional abnormalities in alveolar macrophages lead to accumulation of surfactant within alveoli in mammals. Histologic examination of 6 avian autopsies, including 4 chickens, a turkey, and a cockatiel, revealed accumulation of hypereosinophilic densely arrayed lamellar material in the lungs that was magenta by periodic acid-Schiff stain and diastase resistant. Transmission electron microscopy of the proteinaceous material in 2 cases demonstrated alternating electron-dense and electron-lucent lamellae that formed whorls and had a regular periodicity of 6-14 nm, consistent with pulmonary surfactant. Given the anatomic differences between avian and mammalian lungs, we designated the presented condition "pulmonary proteinosis," which can be observed as both an incidental finding or, when severe, may be a contributing factor to death through respiratory failure.

Pulmonary alveolar proteinosis (PAP) is a disease of surfactant clearance in which functional abnormalities in alveolar macrophages lead to accumulation of surfactant within alveoli in mammals. Histologic examination of 6 avian autopsies, including 4 chickens, a turkey, and a cockatiel, revealed accumulation of hypereosinophilic densely arrayed lamellar material in the lungs that was magenta by periodic acid-Schiff stain and diastase resistant. Transmission electron microscopy of the proteinaceous material in 2 cases demonstrated alternating electron-dense and electron-lucent lamellae that formed whorls and had a regular periodicity of 6-14 nm, consistent with pulmonary surfactant. Given the anatomic differences between avian and mammalian lungs, we designated the presented condition "pulmonary proteinosis," which can be observed as both an incidental finding or, when severe, may be a contributing factor to death through respiratory failure.

The Delta Smelt (Hypomesus transpacificus) is a small, semi-anadromous fish native to the San Francisco Bay-Delta Estuary and has been declared as critically endangered. Their olfactory biology, in particular, is poorly understood and a basic description of their sensory anatomy is needed to advance our understanding of the sensory ecology of species to inform conservation efforts to manage and protect them. We provide a description of the gross morphology, histological, immunohistochemical, and ultrastructural features of the olfactory rosette in this fish and discuss some of the functional implications in relation to olfactory ability. We show that Delta Smelt have a multilamellar olfactory rosette with allometric growth. Calretinin immunohistochemistry revealed a diffuse distribution of olfactory receptor neurons within the epithelium. Ciliated, microvillous and crypt neurons were clearly identified using morphological and immunohistochemical features. The olfactory neurons were supported by robust ciliated and secretory sustentacular cells. Although the sense of smell has been overlooked in Delta Smelt, we conclude that the olfactory epithelium has many characteristics of macrosmatic fish. With this study, we provide a foundation for future research into the sensory ecology of this imperiled fish.