No description available.

No description available.

The purpose of this study was to examine the ventral prostate from Sprague-Dawley rats of the ages two, twelve, and twenty-four months to determine the extent of histological and fine structural change. The tissue was processed for routine light and electron microscopy.

No description available.

No description available.

No description available.

This study of the Norway rat, Rattus norvegicus (Erxleben) and its consortes was undertaken in Utah County to determine : (1} the frequency of infection of Trichinella spiralis (Owen) Railliet, the causative organism of trichinosis in humans, (2) the populations of fleas, lice and mites on the rat, and (3) the occurence of other consortes. This study covered a period from January 1951 through June, 1951. Additional records were made available from studies being made by the Department of Zoology and Entomology, Brigham Young University on parasitic arthropods (listed as Project Ten). The species ot fleas, and those mites which could be determined to the species were studied in relation to population of the consors, habitat, and sex of the rat host. Emphasis was placed on the population aspect ot the consors of the rat.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Indiana University-Purdue University Indianapolis (IUPUI) / The effect of weightlessness on bone and osteoblast precursor cells has previously been studied. A marked decrease in bone formation, an increase in less differentiated committed osteogenic cells (A+A'), and a decrease in preosteoblast cells (C+D) was noted. To date, the effect of hypergravity (2g) on osteoblast histogenesis has not been studied in vivo. In vitro studies using nonphysiologic high levels of gravity (20,40g) have shown an increased proliferation of cloned osteoblast-like cells. The purpose of the present study was to evaluate the effect of hypergravity (2g) on osteoblast histogenesis in the rat periodontal ligament (PDL), on the width of the mesial PDL, and on the percentage of forming bone surface on the mesial side of the tooth. Twenty male Wistar rats (SPF: Harlan Sprague Dawley) were randomly assigned to the centrifuge (experimental) or to the stationary (control) group. The experimental group was centrifuged for 14 days at 2g and the stationary group was housed in identical cages in the centrifuge room. The PDL of the mesial and distal surface of the mesial root of the first maxillary molar was analyzed microscopically 100 μm above and below the midroot area. Nuclear volume morphometry was used to classify periodontal ligament cells as: L cells (<40 μm3), A+A' cells (40-79 μm3), B cells (80-119 μm3), C cells (120-169 μm3), and D cells (>170 μm3). The percent of forming bone surface on the mesial side and the width of the PDL were also measured. A 2x2 factorial ANOVA with repeat measures revealed a significant (p < 0.05) decrease in the C cell population and a nearly significant (p < 0.06) increase in the A+A' cell population in the centrifuge group. Comparing bone surfaces, the forming surface had a significant (p < 0.01) increase in the C and D cell populations, a significant (p < 0.01) decrease in the L and A+A' cell populations, and a significant (p < 0.05) decrease in the B cell population. The stationary group weighed significantly (p < 0.01) more than the centrifuge group post-experiment. And an unpaired t-test revealed a nearly significant (p < 0.06) increase in the percent forming bone surface on the mesial side of the maxillary first molar and no significant difference in mesial PDL width. The results showed that the centrifuge group had a trend toward a block in preosteoblast formation. This is similar to that seen with hypogravity. However, it cannot be concluded at this time if this is a direct gravitational effect or related to other factors such as physiological response to stress. Physical stress has been suggested as a potential mechanism for the observed decrease in weight seen in centrifuged animal, while the PDL width does not seem to be affected by gravitational forces, and thus may not be a sensitive marker to osteoblast differentiation inhibition. Finally, the reason for the increase in forming bone surface in the centrifuged group is unclear.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).