Teaching physiology online: successful use of case studies in a graduate course.

To address the need for greater flexibility in access to higher education, an online graduate course in physiology using case studies was developed and offered in summer 2012. Topics in both animal and human physiology were organized as modules that contained a case study with questions, a prerecorded online lecture, and three research journal articles. We followed best practices for teaching and learning in distance education, including the preparation of materials before the course starting date, a discussion board for responding to pre- and postcase discussion questions, and prompt reply to student queries. For exams, students generated their own questions based on new cases and developed their own case study for the final project. Although only 20% of students had previously taken an online course, all students stated that they would recommend this course to others. Postcase assessment indicated that students found the cases interesting, informative, and presented at the appropriate level. Most students said that the online course took them more time but that they learned more content and used the primary literature more than in a traditional class. Our results indicate that a well-organized physiology course using a case study format is a very effective model for online learning.

Inosine ameliorates the effects of hemin-induced oxidative stress in broilers.

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 the study control birds (n=10) were injected daily with a buffer solution, while hemin birds (n=10) were injected daily (i.p.) with a 20 mg/kg body weight hemin buffer solution. Leukocyte oxidative activity (LOA) and concentrations of plasma uric acid (PUA) were measured. Results from the first study showed that hemin birds had increased levels of LOA (P=0.0333) and lower PUA (P=0.1174). On day 10, control and hemin birds were subdivided into inosine birds (n=5) and hemin/inosine birds (n=5). These birds were given 0.6 M/kg of feed/day of dry inosine. Plasma concentrations of uric acid and LOA were then measured on day 15. Results showed that inosine raised concentrations of PUA (P=0.0001) and lowered LOA (P=0.0044) as induced by hemin. In the second study pretreatment of broilers with hemin prevented the increase in LOA induced by hemin (P=0.0001). These results show that modulating the concentrations of uric acid can markedly affect oxidative stress.

Relationships between renal morphology and diet in 26 species of new world bats (suborder microchiroptera).

The renal morphology of 24 species of mormoopid and phyllostomid bats feeding on six different diets was examined to test evolutionary changes in several structural traits presumably led by dietary shifts from ancestral insectivorous diets. The kidneys of a fish-eating vespertilionid and an insect-eating emballonurid were also examined but not included in the phylogenetic comparison. The length, width, and breadth of the kidneys were used to calculate relative medullary thickness (RMT). Tissues were processed for stereological analysis, and the volumes of the kidney, nephron components, and vasculature were determined. RMT did not correlate with body mass in either animal-eating or plant-eating phyllostomid and mormoopid bats. The shift from insectivory to frugivory and nectarivory was accompanied by a reduction in RMT, a reduction in the percent of renal medulla, and an increase in the percent of renal cortex. No changes in these traits were observed in bats that shifted to carnivorous, omnivorous or sanguinivorous habits. No changes were observed in renal vasculature, in the percentage of cortical and medullary nephron components or of capillaries surrounding the nephrons in any feeding group. Vespertilionid and emballonurid species had similar values in all traits examined as compared to insectivorous phyllostomids and mormoopids. Our data suggest that diet does not influence a single area of the nephron, but rather the entire nephron such that the relative amounts of renal cortex and medulla are affected.

Protein location and elemental composition of urine spheres in different avian species.

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 the spheres was examined using freeze-fracture microscopy. Protein location within the spheres was identified using fluorescein isothiocyanate (FITC). The urine spheres were analyzed for content and internal location of elements using Energy Dispersal System Analysis (EDS). Internally, the spheres consisted of a central nidus surrounded by 3-4 concentric narrow rings of protein. Elements found within the spheres included nitrogen, potassium, calcium, sodium, phosphorus, chloride and sulfur; however, only nitrogen, potassium and chloride were common in the spheres of all species. Nitrogen comprised the majority of the elemental content of the spheres (77-90%) followed by potassium (8-45%), with all other ions present in trace amounts. Unlike protein, the location of elements was random within the spheres. Protein and urate are both negatively charged and known to associate to form the spheres and as potassium is the only cation common to all spheres, it too may play a role in their formation.