No abstract

This research effort compared and contrasted two conceptually different methods for the exploration of human anatomy in the first-year dissection laboratory by accomplished students: "physical" dissection using an embalmed cadaver and "digital" dissection using three-dimensional volume modeling of whole-body CT and MRI image sets acquired using the same cadaver. The goal was to understand the relative contributions each method makes toward student acquisition of intuitive sense of practical anatomical knowledge gained during "hands-on" structural exploration tasks. The main instruments for measuring anatomical knowledge under this conceptual model were questions generated using a classification system designed to assess both visual presentation manner and the corresponding response information required. Students were randomly divided into groups based on exploration method (physical or digital dissection) and then anatomical region. The physical dissectors proceeded with their direct methods, whereas the digital dissectors generated and manipulated indirect 3D digital models. After 6 weeks, corresponding student anatomical assignment teams compared their results using photography and animated digital visualizations. Finally, to see whether each method provided unique advantages, a visual test protocol of new visualizations based on the classification schema was administered. Results indicated that all students, regardless of gender, dissection method, and anatomical region dissected performed significantly better on questions presented as rotating models requiring spatial ordering or viewpoint determination responses in contrast to requests for specific lexical feature identifications. Additional results provided evidence of trends showing significant differences in gender and dissection method scores. These trends will be explored with further trials with larger populations.

No abstract

We propose that estrogen, by regulating expression and secretion of angiogenic factors such as VEGF by glandular epithelial cells of the endometrium, regulates endometrial angiogenesis.

During spermatogenesis, histones are replaced by protamines, which condense and protect sperm DNA. In humans, zinc contributes to sperm chromatin stability and binds to protamine P2 (HP2). Chemical interactions with nuclear protamines, which prevent normal sperm chromatin condensation, may induce changes in the sperm genome and thus affect fertility and offspring development. Since lead has a high affinity for zinc-containing proteins, we investigated lead interactions with HP2 as a novel mechanism of its toxicity to sperm. UV/vis and CD spectroscopy results indicated that HP2 binds Pb(2+) at two different sites, causing a conformational change in the protein. They also provided evidence that thiol groups are primarily involved in Zn(2+) and Pb(2+) binding to HP2 and that HP2 may have additional binding sites for Pb(2+) not related to Zn(2+). HP2 affinities for Pb(2+) and Zn(2+) were very similar, suggesting that Pb(2+) can compete with or replace Zn(2+) in HP2 in vivo. This interaction of lead with HP2 resulted in a dose-dependent decrease in the extent of HP2-DNA binding, although lead interaction with DNA also contributed to this effect. Therefore, the ability of lead to decrease the level of HP2-DNA interaction may result in alterations to sperm chromatin condensation, and thus in reduced fertility.