Assessing changes in attitudes toward engineering and biomechanics resulting from a high school outreach event.

National Biomechanics Day aims to introduce students to the emerging field of biomechanics and improve their perception of engineering and engineers. This quantitative study examines participants' attitude changes following one such event. By prioritizing increasing excitement and engagement over teaching content, we anticipate that students' opinions of engineering and biomechanics will improve following the event. Pre- and post-test surveys consisting of Likert scale and semantic differential (SD) items assessed changes in three key areas: self-identity as a scientist and engineer, attitudes toward engineering, and attitudes toward biomechanics. Based on unpaired and paired student responses, we found significant gains in all three areas. Students agreed more strongly with statements regarding whether they saw themselves as scientists and engineers, and they had improved attitudes toward engineering in general and biomechanics specifically. The SD scales also reflected improved opinions of both science and biomechanics. These more positive attitudes could eventually lead to more students recruited to study a variety of engineering disciplines, ultimately addressing the ongoing national shortage of qualified engineers.

Optimization of a single insertion electrode array for the creation of clinically relevant ablations using high-frequency irreversible electroporation.

High-frequency irreversible electroporation (H-FIRE) is an emerging ablation modality, delivering rapid bursts of bipolar microsecond-duration electrical pulses to non-thermally ablate tissue including tumors. With advantages over current electroporation techniques including mitigation of muscle stimulation and reduced susceptibility to heterogeneous tissue properties, H-FIRE may produce more uniform and predictable ablations and can potentially be delivered with a single applicator device. However, the resulting ablations tend to be smaller than those provided with equivalent energy monopolar pulse protocols. Here, we develop numerical simulations that demonstrate the potential for clinically relevant ablations with H-FIRE delivered via a single insertion technique comprised of an expandable array and a distally placed grounding pad. Based on existing in vivo data and new in vitro results, delivery of H-FIRE with a clinical IRE single electrode probe (1 cm long) is predicted to produce a 2.2 cm3 ablation while an optimized eight tine array produces a 3.2 cm3 ablation when the same H-FIRE bursts are delivered (5000 V). We demonstrate that alternative pulse protocols can be used to increase ablation volumes with this optimized array and these results indicate that in vivo investigation of a single insertion array and grounding pad are warranted.

Age-related effects on the potency of human adipose-derived stem cells: creation and evaluation of superlots and implications for musculoskeletal tissue engineering applications.

Human adipose-derived stem cells (hASC) are now a prevalent source of adult stem cells for studies in tissue engineering and regenerative medicine. However, researchers utilizing hASC in their investigations often encounter high levels of donor-to-donor variability in hASC differentiation potential. Because of this, conducting studies with this primary cell type can require extensive resources to generate statistically significant data. We present a method to generate pooled donor cell populations, termed "superlots," containing cell populations derived from four to five age-clustered donors. The goal of generating these superlots was to 1) increase experimental throughput, 2) to utilize assay resources more efficiently, and 3) to begin to establish global hASC differentiation behaviors that may be associated with donor age. With our superlot approach, we have validated that pooled donor cell populations exhibit proliferative activity representing the combined behavior of each individual donor cell line. Further, the superlots also exhibit differentiation levels roughly approximating the average combined differentiation levels of each individual donor cell line. We established that high donor-to-donor variability exists between the pre-, peri-, and postmenopausal age groupings and that proliferation and differentiation characteristics can vary widely, independent of age. Interestingly, we did observe that cell lines derived from postmenopausal donors demonstrated a relatively high proclivity for osteogenic differentiation and a relatively lowered proclivity for adipogenic differentiation as compared with cells derived from pre- and perimenopausal donors. In general, superlots effectively represented the average differentiation behavior of each of their contributing cell populations and could provide a powerful tool for increasing experimental throughput to more efficiently utilize resources when studying hASC differentiation.

Glutathione levels in human tumors.

This review summarizes clinical studies in which glutathione was measured in tumor tissue from patients with brain, breast, gastrointestinal, gynecological, head and neck and lung cancer. Glutathione tends to be elevated in breast, ovarian, head and neck, and lung cancer and lower in brain and liver tumors compared to disease-free tissue. Cervical, colorectal, gastric, and esophageal cancers show both higher and lower levels of tumor glutathione. Some studies show an inverse relationship between patient survival and tumor glutathione. Based on this survey, we recommend approaches that may improve the clinical value of glutathione as a biomarker.

Non-invasive monitoring of L-2-oxothiazolidine-4-carboxylate metabolism in the rat brain by in vivo 13C magnetic resonance spectroscopy.

The cysteine precursor L-2-oxothiazolidine-4-carboxylate (OTZ, procysteine) can raise cysteine concentration, and thus glutathione levels, in some tissues. OTZ has therefore been proposed as a prodrug for combating oxidative stress. We have synthesized stable isotope labeled OTZ (i.e. L-2-oxo-[5-(13)C]-thiazolidine-4-carboxylate, (13)C-OTZ) and tracked its uptake and metabolism in vivo in rat brain by (13)C magnetic resonance spectroscopy. Although uptake and clearance of (13)C-OTZ was detectable in rat brain following a bolus dose by in vivo spectroscopy, no incorporation of isotope label into brain glutathione was detectable. Continuous infusion of (13)C-OTZ over 20 h, however, resulted in (13)C-label incorporation into glutathione, taurine, hypotaurine and lactate at levels sufficient for detection by in vivo magnetic resonance spectroscopy. Examination of brain tissue extracts by mass spectrometry confirmed only low levels of isotope incorporation into glutathione in rats treated with a bolus dose and much higher levels after 20 h of continuous infusion. In contrast to some previous studies, bolus administration of OTZ did not alter brain glutathione levels. Even a continuous infusion of OTZ over 20 h failed to raise brain glutathione levels. These studies demonstrate the utility of in vivo magnetic resonance for non-invasive monitoring of antioxidant uptake and metabolism in intact brain. These types of experiments can be used to evaluate the efficacy of various interventions for maintenance of brain glutathione.