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The primary purpose of this study was to determine the association between Apolipoprotein E (APOE) genotype and head impact response in high school athletes. The secondary purpose was to determine if quality of life (QoL) and cognitive functioning scores significantly differ between Apolipoprotein (APOE) rare allele carriers versus non-carriers within a poor head impact response (PHIR) group of high school athletes. Thirty (28 males, 2 females) high school athletes playing high head impact sports participated in the study. A between-subjects design was used. Primary aim one independent variable was genotype (i.e., APOE E4 carriers vs. non-carriers and APOE G-219T carriers vs. non-carriers) and dependent variable was group [i.e., normal head impact response (NHIR) vs. PHIR]. Statistical analysis consisted of Fisher's exact tests. Alpha level was set at p p p = .002) in the overall QoL scores between APOE G-219T promoter rare allele carriers versus non-carriers within the PHIR group. No other statistically significant differences were found; however, there was a trend (p = .007) found in the psychosocial subscores in the APOE G-219T promoter rare allele carriers versus non-carriers within the PHIR group. Carrying an APOE rare G-219T rare allele was associated with significantly lower QoL scores within the PHIR group, these results indicate that athletes with intrinsic (e.g., genotype) risk factors may need more education and different treatment following head impacts. / Kinesiology

Nineteen elite (E) gymnasts (>15hours/week gymnastic training), 14 high recreation (HR) gymnasts (8-15hours/week), and 15 low recreation (LR) gymnasts (1-7. 9 hours/week) were investigated to determine the effects of varying volumes of gymnastic training on bone mineral density (BMD) in prepubescent girls. Two normoactive control groups were additionally investigated to determine whether there was a magnitude effect of mechanical loading on BMD: 16 controls (C) and 15 height-and weight-matched controls (M). The mother of each daughter was measured in order to control and investigate the familial component of bone mass. Areal bone mineral density at the left proximal femur, lumbar spine (LS), and whole body (WB) and % body fat were measured by dual energy x-ray absorptiometry (DXA), and volumetric BMD was measured at the distal radius by peripheral QCT (pQCT). DXA BMD measures were corrected for bone size and expressed as bone mineral apparent density (BMAD). The HR group was significantly younger (8.68 ± 0.844 y, mean± SD) than both the E (10.02 ± 0.776 y) and C (9.96 ± 0.898 y) groups. The C group was significantly heavier (38.88 ± 4.868 kg) than the E (27.15 ± 2.819 kg), HR. (25.44 ± 3.564 kg), LR (32.98 ± 5.786 kg), and M (26.95 ± 3.301 kg) groups. Additionally, the LR group was significantly heavier than all other groups, with the exception of the C group. Femoral neck (FN) BMD was only significantly different between the E (0.706 ± 0.051 g•cm⁻²) and LR (0.649 ± 0.069 g•cm⁻²) groups. FNBMAD was only greater in the E (0.232 ± 0.048 g•cm⁻³) group compared to the C (0.191 ± 0.052 g•cm⁻³) group. LSBMAD and WBBMAD were significantly greater in both E (0.233 ± 0.019 and 0.100 ± 0.008 g•cm⁻³) and HR (0.239 ± 0.038 and 0.100 ± 0.006 g•cm⁻³) groups when compared to the LR (0.212 ± 0.022 and 0.090 ± 0.008 g•cm⁻³) and C (0.219 ± 0.020 and 0.085 ± 0.004 g•cm⁻³) groups, respectively. Total radial and cortical radial BMD was greater in both E (360.50 ± 51.569 and 484.28 ± 70.179 mg•cm⁻³) and HR (373.10 ± 45.318 and 480.66 ± 46.720 mg•cm⁻³) groups compared to the C (296.61 ± 29.677 and 426.144 ± 37.652 mg•cm⁻³) and M (306.42 ± 24.430 and 414.571 ± 25.194 mg•cm⁻³) groups, respectively. Radial trabecular BMD was greater in both E (211. 19 ± 38. 202 mg•cm⁻³) and HR (212. 61 ± 44.299 mg•cm⁻³) groups compared to the LR (175.89 ± 29.191 mg•cm⁻³), C (162.68 ± 27.304 mg•cm⁻³), and M (171.05 ± 30.639 mg•cm⁻³) groups. There were no significant differences for any bone measure among the groups of mothers. Mother-daughter correlations were relatively weak, and often insignificant, for BMD measures (r = 0.10-0.37), but strong for radial morphometric measures (r = 0.43-0.55). Radial trabecular BMD (r = 0.37; p<0.01) was more significantly correlated with gymnastic training volume (hours/week) than radial cortical BMD (0.30; p<0.05). These results suggest that there is a volume of training effect on BMD and a magnitude effect of mechanical loading on BMD. It appears that trabecular bone at the distal radius may adapt more rapidly or be more sensitive than cortical BMD to the strains imposed by impact loading. Additionally, it appears that, during prepubescence in females, bone morphometric properties may be more genetically regulated than bone mineralization. / Thesis / Master of Science (MSc)

To assess the impacts of non-point source pollution on Ontarios wetlands I examined the landuse in the watershed, the water and sediment quality, and the aquatic vegetation in 22 wetlands. I characterized the primary contaminants that enter marshes in Ontario and relate their concentrations to the relative amounts and types of land use in their watershed. I measured levels of nutrients, suspended particulates and trace organics in water and sediment. Species richness and structural diversity of the vegetative community was used as an indicator of wetland health. I included a comparison of two techniques, immunoassays and gas-chromatography (GC) to measure trace organics (PAHs and metolachlor; Chapter 1). Comparison of results from both techniques indicated that immunoassays overestimated analyte concentration by approximately a third. I utilized the immunoassay results, along with selected water quality variables, to characterize contaminants entering these wetlands (Chapter 2). Watersheds containing greater than 95% agriculture contributed the highest suspended particulate, compared with those dominated by urban or forested land. Using multivariate statistics I identified important water and sediment variables that structured these wetlands to be: total phosphorus (TP), ammonia nitrogen (TAN), suspended solids (TSS), specific conductance (COND), sediment phosphorus CTPsed) and inorganic material (lnorgsed) in the sediment. Of these TP, COND and Inorgsed were negatively related to the submergent plant community, while TPsed was positively related. There was no relationship between water quality and the floating or emergent plants but the structural diversity of the plant community was negatively affected by poor water quality. The negative impact of developed land in the watershed on the health of the aquatic plant communities underscores the need to maintain natural areas to trap nutrients and sediments in runoff. / Thesis / Master of Science (MS)