Refinement of habituation procedures in diet-induced obese mice.

Orogastric gavage, while a common method for delivering experimental substances in mice, has been shown to induce stress. To minimize the associated stress with this procedure, sham gavage prior to the start of experiment is a common method for habiutating mice. We investigated whether handling and restraint could replace sham treatment in the acclimatization protocol. Mice were either undisturbed, hand-restrained for 10 s or sham-gavaged daily for six days prior to eight days of twice daily gavage. The results showed that repetitive restraint and gavage had no differences in body weight after eight days of treatment compared with the body weights at the start of treatment, whereas animals left undisturbed lost significant weight once treatment began. These data suggest that procedure refinement by replacing sham treatment with hand restraint is sufficient to acclimatize mice to the stress associated with gavage.

Spontaneous pulmonary alveolar proteinosis in captive "moustached tamarins" (Saguinus mystax).

Pulmonary alveolar proteinosis is a rare human disease characterized by accumulation of surfactant in alveoli without generating an inflammatory response. Lung lesions resembling pulmonary alveolar proteinosis were observed in 7 adult tamarins (5 males and 2 females). Gross lesions were characterized by areas of discoloration, slight bulging over the lung parenchyma, and occasional consolidation. Histologic examination of tamarin lung samples revealed intra-alveolar accumulation of amorphous, amphophilic, periodic acid-Schiff-positive, finely granular to dense material. In some cases, type II pneumocyte hypertrophy and hyperplasia were observed with pleural and septal thickening and fibrosis. Large numbers of intra-alveolar foamy macrophages were noted surrounding and/or in the vicinity of the lesions. Immunohistochemical analysis of the lung lesions using polyclonal (surfactant proteins A, B, and C) and monoclonal (surfactant protein D) antibodies revealed the granular material to be composed largely of surfactant protein B, followed by surfactant protein A. Surfactant proteins C and D were present in lesser quantities, with the latter observed surrounding the lipoproteinaceous deposits. Transmission electron microscopy of the affected lungs showed numerous, irregularly shaped osmiophilic lamellar bodies in type II pneumocytes. The cytoplasm in alveolar macrophages was expanded, containing ingested surfactant with swollen mitochondria and rough endoplasmic reticulum. Thoracic radiographs, available in 1 animal, depicted the lesions as small multifocal opacities randomly distributed in cranial and diaphragmatic lung lobes. This is, to the authors' knowledge, the first report of spontaneous pulmonary alveolar proteinosis in nonhuman primates.