Burn Injury Reduces Neutrophil Directional Migration Speed in Microfluidic Devices

Thermal injury triggers a fulminant inflammatory cascade that heralds shock, end-organ failure, and ultimately sepsis and death. Emerging evidence points to a critical role for the innate immune system, and several studies had documented concurrent impairment in neutrophil chemotaxis with these post-burn inflammatory changes. While a few studies suggest that a link between neutrophil motility and patient mortality might exist, so far, cumbersome assays have prohibited exploration of the prognostic and diagnostic significance of chemotaxis after burn injury. To address this need, we developed a microfluidic device that is simple to operate and allows for precise and robust measurements of chemotaxis speed and persistence characteristics at single-cell resolution. Using this assay, we established a reference set of migration speed values for neutrophils from healthy subjects. Comparisons with samples from burn patients revealed impaired directional migration speed starting as early as 24 hours after burn injury, reaching a minimum at 72–120 hours, correlated to the size of the burn injury and potentially serving as an early indicator for concurrent infections. Further characterization of neutrophil chemotaxis using this new assay may have important diagnostic implications not only for burn patients but also for patients afflicted by other diseases that compromise neutrophil functions.     

Effects of dexamethasone on carnitine metabolism in liver and extrahepatic tissues

The in vivo effects of dexamethasone administration on liver and extrahepatic tissue carnitine concentrations were assessed in 48-h-starved rats. In heart and kidney, but not in liver, dexamethasone significantly increased total carnitine concentration. Acute (2.5 h) treatment with 2-tetradecylglycidate (TDG), a specific inhibitor of carnitine palmitoyl transferase 1, not only increased total hepatic carnitine concentrations, but also permitted an effect of dexamethasone (a further increase in hepatic carnitine concentration). The results are discussed in terms of acute (substrate-mediated) and chronic (hormonal) control of carnitine turnover.     

The effect of substrate modification on binding of porcine pancreatic alpha amylase: hydrolysis of modified amylose containing D-allose residues

A modified amylose containing 10% of tritiated D-allose residues has been hydrolyzed by porcine pancreatic alpha amylase (PPA). This reaction produced a number of radioactive oligosaccharides of low molecular weight, including modified mono-, di-, and tri-saccharides, as well as larger products. Analysis of these products by chemical and enzymic methods identified D-allose, two isomers of modified maltose, and isomers of modified maltotriose. These results may be interpreted in terms of current PPA models to indicate that D-allose residues may be productively bound at all five subsites of the active site of the enzyme. The distribution of modified residues in these products, however, further suggests that productive binding of D-allose at the subsite where catalytic attack occurs (subsite 3) is less favorable than binding of D-glucose. These results are compared with results of a series of PPA substrates having modifications at C-3 and at other positions. Trends observed in enzyme hydrolysis of these modified substrates reflect factors that contribute to PPA catalysis, with respect to steric, electronic, and hydrogen-bonding interactions between enzyme and substrate.     

The Invisibility of Disability: Using Dance to Shake from Bioethics the Idea of ‘Broken Bodies’

Complex social and ethical problems are often most effectively solved by engaging them at the messy and uncomfortable intersections of disciplines and practices, a notion that grounds the InVisible Difference project, which seeks to extend thinking and alter practice around the making, status, ownership, and value of work by contemporary dance choreographers by examining choreographic work through the lenses of law, bioethics, dance scholarship, and the practice of dance by differently‐abled dancers. This article offers a critical thesis on how bioethics has come to occupy a marginal and marginalizing role in questions about the differently‐abled body. In doing so, it has rendered the disabled community largely invisible to and in bioethics. It then defends the claim that bioethics – as a social undertaking pursued collaboratively by individuals from different disciplines – must take much better notice of the body and the embodied individual if it is to better achieve its ends, which include constructing a moral and just society. Finally, this article considers how the arts, and specifically dance (and here dance by differently‐abled dancers), provides us with rich evidence about the body and our ability to respond positively to normally ‘othered’ bodies. It concludes that greater attention to empirical evidence like that being generated in InVisible Difference will help to expand the reach and significance of bioethics, and thereby its relevance to (and consciousness of) important questions about the status of bodies and bodily differences, which must be considered as central to its ambitions.     

Investigating Models of Protein Function and Allostery With a Widespread Mutational Analysis of a Light-Activated Protein

To investigate the relationship between a protein’s sequence and its biophysical properties, we studied the effects of more than 100 mutations in Avena sativa light-oxygen-voltage domain 2, a model protein of the Per-Arnt-Sim family. The A. sativa light–oxygen–voltage domain 2 undergoes a photocycle with a conformational change involving the unfolding of the terminal helices. Whereas selection studies typically search for winners in a large population and fail to characterize many sites, we characterized the biophysical consequences of mutations throughout the protein using NMR, circular dichroism, and ultraviolet/visible spectroscopy. Despite our intention to introduce highly disruptive substitutions, most had modest or no effect on function, and many could even be considered to be more photoactive. Substitutions at evolutionarily conserved sites can have minimal effect, whereas those at nonconserved positions can have large effects, contrary to the view that the effects of mutations, especially at conserved positions, are predictable. Using predictive models, we found that the effects of mutations on biophysical function and allostery reflect a complex mixture of multiple characteristics including location, character, electrostatics, and chemistry.     

Seasonal changes in density and tissue distribution of Onchocerca cervicalis microfilariae in ponies and related changes in Culicoides variipennis populations in Louisiana

Seasonal changes in density and spatial distribution of Onchocerca cervicalis microfilariae were studied in ventral-midline skin of 15 infected pony mares in southern Louisiana. Triple running mean analysis of data over a 13-mo period indicated that a distinct pattern exists in total microfilariae population density and in microfilariae occurrence in different levels of the dermis. Microfilariae density reaches peak levels in the spring followed by a 58% decrease in the summer, a 19% increase in the fall, and a decrease to the lowest numbers in the winter. Microfilariae were found in all levels of the skin during the spring, summer, and fall but were not found in the superficial layers of the dermis during the winter months. The population density of Culicoides variipennis, a demonstrated vector of O. cervicalis, appeared to have seasonal fluctuations similar to the changes in microfilarial density. Harmonic wave analysis of microfilariae density data in individual ponies showed that all individuals did not follow the population trend.     

Mating patterns in the golden lion tamarin (Leontopithecus rosalia): continuous receptivity and concealed estrus

Sociosexual behavior was monitored on a daily basis for 3 months in 5 pairs of golden lion tamarins (Leontopithecus rosalia). Urine samples were collected daily from each female and urinary estrogen cycles were determined by radioimmunoassay. Mounts and copulations were observed during all phases of the estrogen cycle. Peaks or regular cycles in sexual behavior were not documented. There were no significant changes in affiliative behavior by females or males that were associated with changes in urinary estrogen values. A negative relationship between pair bond duration and frequency of sexual interactions was observed: newly established pairs exhibited 2-6 times more frequent sexual behavior than a long-established pair. The lack of a conspicuous sexual signal in female golden lion tamarins may be related to a pattern of continuous sexual receptivity. Both reproductive patterns, concealed estrus and continuous receptivity, are explicable in relation to either monogamous or polyandrous mating systems.     

Isolation of intact high-molecular-weight DNA by using guanidine isothiocyanate.

A method for obtaining high-molecular-weight chromosomal DNA from Bacteroides intermedius and Bacteroides gingivalis is described. This technique is a modification of the guanidine isothiocyanate isolation procedure for RNA and should be useful for isolating intact DNA from organisms with high endogenous nuclease activity.