Giovanni Casotti

Learn More
The kidneys of Anna's hummingbird (Calypte anna) differ in several signi®cant ways from those of other birds that have been examined. The kidneys of this nectarivore contain very little medullary tissue; 90% of the total volume of the kidneys is cortical tissue, with medulla accounting for only an additional 2%. More than 99% of the nephrons are the(More)
The organization of the renal medulla of the Gambel's quail, Callipepla gambelii, kidney was examined to determine the number of loops of Henle and collecting ducts and the surface area occupied by the different nephron segments as a function of distance down the medullary cones. Eleven medullary cones were dissected from the kidneys of four birds, and the(More)
Seasonal variability in kidney morphology of the house sparrow Passer domesticus was examined using light microscopy. Sparrows were captured from the wild in winter, spring, summer and autumn. The kidneys were perfused with half-strength Karnovsky's fixative and processed for light microscopy by embedding in either paraffin wax or JB4 acrylic resin.(More)
The renal anatomy of three species of sparrows, two from mesic areas, the House Sparrow (Passer domesticus) and Song Sparrow (Melospiza melodia), and one salt marsh species, the Savannah Sparrow (Passerculus sandwichensis) was examined. Electron microscopy was used to describe the ultrastructure of the nephron. In addition, stereology was used to quantify(More)
Recent evidence has demonstrated that inquiry-based physiology laboratories improve students' critical- and analytical-thinking skills. We implemented inquiry-based learning into three physiology courses: Comparative Vertebrate Physiology (majors), Human Physiology (majors), and Human Anatomy and Physiology (nonmajors). The aims of our curricular(More)
The objective of these studies was to determine whether inosine, a precursor of the antioxidant uric acid, can ameliorate hemin-induced oxidative stress. Dietary inclusion of inosine was begun either before or after hemin-induced oxidative stress. Broilers (4 weeks) were divided into four treatment groups (Control, Hemin, Inosine, Hemin/Inosine). Throughout(More)
A mathematical model was used to investigate how concentrated urine is produced within the medullary cones of the quail kidney. Model simulations were consistent with a concentrating mechanism based on single-solute countercurrent multiplication and on NaCl cycling from ascending to descending limbs of loops of Henle. The model predicted a urine-to-plasma(More)
In birds, the kidneys and lower intestine function in osmoregulation. A 271-amino acid homologue to aquaporin-1 (AQP-1) was isolated from the kidneys, cecae, proximal and distal rectum, and coprodeum of the lower intestine in the house sparrow (Passer domesticus). This protein has six transmembrane domains connected by two cytoplasmic loops and three(More)
The anionic charge barrier and the endothelial and epithelial pore sizes on the glomerular filtration barrier (GFB) were examined in white leghorn chickens (Gallus gallus). Ruthenium red was used to stain anionic charge sites on the GFB. The tissue was treated by normal dehydration and freeze substitution dehydration for transmission electron microscopy(More)
We examined the internal morphology, location of protein, and identity and location of elements, in avian urate-containing spheres in 9 species of birds. The urine spheres were collected from voided samples. The spheres ranged in size from 0.5-5.0 microm, except in the domestic fowl, where they ranged up to 10 microm in diameter. The internal morphology of(More)