A New Realization of SI for Organic Chemical Measurement: NIST PS1 Primary Standard for Quantitative NMR (Benzoic Acid)

Metrological traceability to common references supports the comparability of chemical measurement results produced by different analysts, at various times, and at separate places. Ideally, these references are realizations of base units of the International System of Units (SI). ISO/IEC 17025 (Clause 6.5) states that traceability of measurement results is a necessary attribute of analytical laboratory competence, and as such, has become compulsory in many industries, especially clinical diagnostics and healthcare. Historically, claims of traceability for organic chemical measurements have relied on calibration chains anchored on unique reference materials with linkage to the SI that is tenuous at best. A first-of-its-kind National Institute of Standards and Technology (NIST) reference material, ultrapure and extensively characterized PS1 Benzoic Acid Primary Standard for quantitative NMR (qNMR), serves as a definitive, primary reference (calibrant) that assuredly links the qNMR spectroscopy technique to SI units. As qNMR itself is a favorable method for accurate, direct characterization of chemical reference materials, PS1 is a standard for developing other traceable standards and is intended to establish traceability for the measurement of thousands of organic chemical species. NIST PS1 will play a critical role in directly promoting accuracy and worldwide comparability of measurement results produced by the chemical measurement community, supporting the soundness of clinical diagnostics, food safety and labeling, forensic investigation, drug development, biomedical research, and chemical manufacturing. Confidence in this link to the SI was established through (i) unambiguous identification of chemical structure; (ii) determinations of isotopic composition and molecular weight; (iii) evaluation of the respective molecular amount by multiple primary measurement procedures, including qNMR and coulometry; and (iv) rigorous evaluation of measurement uncertainty using state-of-the-art statistical methods and measurement models.

Abstract 4280: Utilizing a selective agonist of the intermediate-affinity IL-2 receptor with an improved pharmacokinetic profile leads to an enhanced immunostimulatory response With reduced toxicity in mice

RDB 1450 is an engineered fusion protein which selectively activates the intermediate-affinity IL-2 receptor present on NK cells and memory CD8 T cells. In rodents, RDB 1450 has a half-life of 6-8 hours, compared to a half-life of minutes for recombinant human IL-2 (rhIL-2). Repeat daily dosing (QD) of RDB 1450 in mice results in marked expansion of NK cells and CD8+CD44high T cells, with minimal expansion of CD4+ regulatory T cells (Tregs). Higher QD doses elicit more pronounced effector cell expansion with modest pulmonary edema. TID delivery of the same total daily dose of RDB 1450 enhances the immunological responses in the absence of pulmonary edema. These results suggest that prolonged delivery of reduced concentrations of RDB 1450 drive the desired immune responses with improved tolerability. In contrast, high circulating concentrations of rhIL-2 are required to stimulate effector cells due to its preferential activation of Tregs at lower concentrations. The selectivity profile and favorable pharmacokinetics of RDB 1450 highlight its potential as a novel, differentiated immunotherapeutic agent for the treatment of cancer.

Citation Format: Heather C. Losey, Jared E. Lopes, Reginald L. Dean, Heather Flick, Madison Gomes, Michael R. Huff, Rosemarie A. Moroso, Lei Sun, Chunhua Wang, Julie F. Waters, Juan C. Alvarez. Utilizing a selective agonist of the intermediate-affinity IL-2 receptor with an improved pharmacokinetic profile leads to an enhanced immunostimulatory response With reduced toxicity in mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4280. doi:10.1158/1538-7445.AM2015-4280

Managing risk at the Tucson Sector of the U.S. Border Patrol

This article describes a risk analysis used to inform resource allocation at the Tucson Sector of the U.S. Border Patrol, the busiest sector for alien and drug trafficking along the Southwest land border with Mexico. The model and methodology that underlie this analysis are generally applicable to many resource allocation decisions regarding the management of frequently occurring hazards, decisions regularly made by officials at all levels of the homeland security enterprise. The analysis was executed by agents without previous risk expertise working under a short time frame, and the findings from the analysis were used to inform several resource allocation decisions.

Variation in within-bone stiffness measured by nanoindentation in mice bred for high levels of voluntary wheel running

The hierarchical structure of bone, involving micro-scale organization and interaction of material components, is a critical determinant of macro-scale mechanics. Changes in whole-bone morphology in response to the actions of individual genes, physiological loading during life, or evolutionary processes, may be accompanied by alterations in underlying mineralization or architecture. Here, we used nanoindentation to precisely measure compressive stiffness in the femoral mid-diaphysis of mice that had experienced 37 generations of selective breeding for high levels of voluntary wheel running (HR). Mice (n = 48 total), half from HR lines and half from non-selected control (C) lines, were divided into two experimental groups, one with 13-14 weeks of access to a running wheel and one housed without wheels (n = 12 in each group). At the end of the experiment, gross and micro-computed tomography (microCT)-based morphometric traits were measured, and reduced elastic modulus (E(r)) was estimated separately for four anatomical quadrants of the femoral cortex: anterior, posterior, lateral, and medial. Two-way, mixed-model analysis of covariance (ancova) showed that body mass was a highly significant predictor of all morphometric traits and that structural change is more apparent at the microCT level than in conventional morphometrics of whole bones. Both line type (HR vs. C) and presence of the mini-muscle phenotype (caused by a Mendelian recessive allele and characterized by a approximately 50% reduction in mass of the gastrocnemius muscle complex) were significant predictors of femoral cortical cross-sectional anatomy. Measurement of reduced modulus obtained by nanoindentation was repeatable within a single quadrant and sensitive enough to detect inter-individual differences. Although we found no significant effects of line type (HR vs. C) or physical activity (wheel vs. no wheel) on mean stiffness, anterior and posterior quadrants were significantly stiffer (P < 0.0001) than medial and lateral quadrants (32.67 and 33.09 GPa vs. 29.78 and 30.46 GPa, respectively). Our findings of no significant difference in compressive stiffness in the anterior and posterior quadrants agree with previous results for mice, but differ from those for large mammals. Integrating these results with others from ongoing research on these mice, we hypothesize that the skeletons of female HR mice may be less sensitive to the effects of chronic exercise, due to decreased circulating leptin levels and potentially altered endocannabinoid signaling.

Mode-mixity-dependent adhesive contact of a sphere on a plane surface

Tangential loading in the presence of adhesion is highly relevant to biological locomotion, but mixed-mode contact of biological materials or similar soft elastomers remains to be well understood. To better capture the effects of dissipation in such contact problems owing to viscoelasticity or irreversible interfacial adhesive processes, a model is developed for the combined adhesive and tangential loading of a rigid sphere on a flat half-space which incorporates a phenomenological model of energy dissipation in the form of increased effective work of adhesion with increasing degree of mode mixity. To verify the model, contact experiments are performed on polydimethylsiloxane (PDMS) samples using a custom-built microtribometer. Measurements of contact area during mixed normal/tangential loading indicate that the strong dependence of the effective work of adhesion upon mode mixity can be captured effectively by the phenomenological model in the regime where the contact area stayed circular and the slip was negligible. Rate effects were seen to be described by a power-law dependence upon the crack front velocity, similar to observations of rate-dependent contact seen for pure normal loading.

Internalization of horseradish peroxidase isozymes by pancreatic acinar cells in vitro

We examined the uptake and fate of four horseradish peroxidase (HRP) isozymes (Type VI, VII, VIII, and IX) in isolated pancreatic acinar cells. The pattern of uptake was similar for all the isozymes examined, with the exception of Type IX. Very little Type IX HRP was internalized by the cells, and what endocytosis did occur was primarily from the apical cell surface in coated vesicles. In contrast, HRP Type VI, VII, and VIII appeared to be endocytosed largely at the basolateral cell surface. Initially, the tracer was found in smooth vesicles and tubules near the plasma membrane. The tubules resembled the basal lysosomes known to be present in these cells. At the early time points, HRP reaction product was also present in multivesicular bodies (MVBs). By 60 min, the HRP was localized in MVBs, vesicles, and tubules adjacent to the Golgi apparatus. By 12 hr after exposure to the isozymes, the tracer was present in small apical vesicles. At no time could reaction product be localized in the rough endoplasmic reticulum, Golgi saccules, or secretory granules. The results of this study suggest that the charge of a soluble-phase marker has little effect on its uptake or intracellular distribution.

Growth of exocrine acinar cells on a reconstituted basement membrane gel

Methods have been developed for culturing a dividing population of morphologically differentiated rat parotid, lacrimal, and pancreatic acinar cells in vitro. Isolated acinar cells were plated onto tissue culture dishes coated with a three-dimensional, reconstituted basement membrane gel. After attachment in Ham's nutrient mixture F12, the cells were cultured at 35 degrees C in F12 supplemented with 10% heat inactivated rat serum, epidermal growth factor, dexamethasone, insulin, transferrin, selenium, putrescine, reduced glutathione, ascorbate, penicillin, streptomycin, and the appropriate secretagogue. Under these conditions, the cells attached rapidly and DNA synthesis was initiated within 2 to 3 d. Although the cells flattened on the substratum, they continued to maintain their differentiated morphology. The cells contained secretory granules, and the secretory enzymes peroxidase and amylase could be detected. The use of a reconstituted basement membrane gel proved critical for the attachment and growth of exocrine acinar cells.