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The cause of diabetic polyneuropathy is at present unknown. Abnormalities of the vasa nervorum are well documented, but a causal relationship between their occurrence and that of diabetic polyneuropathy remains equivocal. Recent studies have reported findings that support this hypothesis, in particular the claim that the number of "closed" endoneurial capillaries is greater in diabetic neuropathy than in control subjects, this being positively correlated with the severity of neuropathy. As these studies were undertaken on elderly diabetic patients (mean age > 50 years), accompanying vascular disease would not be unexpected. Perineurial basal laminal thickening has also been observed in patients with diabetic neuropathy, but its relationship to concomitant microangiopathy has not so far been documented. I have examined sural nerve biopsies from a series of 27 younger diabetic patients with symmetric distal sensory and autonomic neuropathy (mean age 39.8 years). Morphometric observations on endoneurial capillaries and perineurial cells were compared with results from age-matched organ donor control cases and patients with type I hereditary motor and sensory neuropathy (HMSN I). Perineurial basal lamina thickness was significantly greater in the diabetic cases than in the organ donor control group. Capillary luminal area did not differ between the 3 groups and the presence of "closed" capillaries in the diabetic cases was not confirmed. Capillary density was also comparable between the diabetic and organ donor cases, but was reduced in patients with HMSN I, this being related to hypertrophic changes and a resultant increase in fascicular area. The finding that transverse capillary endothelial cell area, and nuclear and pericapillary basal laminal area were all increased both in patients with diabetes and HMSN I make it difficult to present these abnormalities as evidence in favour of a vascular basis for the neuropathy as HMSN I is a condition in which a vascular basis can be discounted.

This is a quantitative, survey-based study of Iowa community college faculty members. The survey was administered in the spring of 2011 to all faculty members identified by their colleges as being employed full time. This study compares the demographics of math and science faculty members to faculty within the arts and sciences who do not teach math or science. Comparisons of how the two groups interact with students and what they identify as barriers to student success are included, as well as their attitudes about mentoring, encouraging students, and their roles in student recruitment and student retention. Highly correlated variables are grouped as factors and used in the construction of prediction models for faculty engagement in student recruitment and student retention efforts. A contrast in the cultures of the math/science faculty members as compared to the non-math/science faculty is considered for its impact on faculty engagement with students and those variables believed to support undergraduate student success. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]