The use of osmolality as an aid to establishing consistent fixation quality: studies on the kidney of the domestic fowl

Ultrastructure of lipid-containing cells of the anterior pituitary gland of the domestic chicken, Gallus domesticus

A combination of light and electron microscopy techniques was applied to characterize a luteinizing hormone (LH)-gonadotroph-like cell in the anterior pituitary gland of the adult domestic chicken. This cell type (mean +/- sem, 91 +/- 8 microns2) was larger than typical LH-gonadotrophs (71 +/- 5 microns2, p < 0.01) and seen in pituitary glands from adult males but not those from adult females of the same age. The ultrastructural features of these cells were similar to typical LH-gonadotrophs in the same section, except for the presence of large (1,126 +/- 77 nm diameter), round, or polymorphic electron-dense inclusions (14 +/- 3 per cell) in the cisternae of the endoplasmic reticulum. When resin sections of anterior pituitary gland were stained with the vapours from the fixative osmium tetroxide and a solution of potassium ferricyanide, inclusions were found that appeared to be lipid in nature and were circumscribed by the cisternal membranes of the endoplasmic reticulum. These lipid inclusions were associated occasionally with acid phosphatase and lysosome-like bodies. The cellular pigment, lipofuscin, considered to be a marker of aging, was absent from the anterior pituitary glands from these adult chickens. These observations suggest that the appearance of lipid in LH-gonadotrophs is unlikely to be age-related and an alternative explanation is discussed in relation to a sex difference in the LH response of adult chickens to gonadotrophin-releasing hormone (GnRH).

Pathogenesis of infectious bronchitis nephritis. 1. Morphometric analysis of kidney proximal tubular epithelium in chickens

The ultrastructure of the proximal tubular epithelial cells in chicken kidneys was examined throughout the course of an experimental infection with infectious bronchitis virus. A quantitative assessment of the structural changes in the cells was related to these in normal cells. Significant alterations were detected in the membrane structures and in the mitochondria. There was a reduction in surface area of the microvillus membrane, the basolateral membrane and the apical tubular membrane. There were alterations in the shape of mitochondrial profiles and a decrease in the volume density of mitochondria. Vesicular structures, which are a possible site of viral release, were observed in the lateral surface of cells. These changes in the functional components of the cells indicate impaired transport of ions and water. The results demonstrate the value of stereological methods for the study of viral-host cell interactions in the pathogenesis of viral disease.