Unconstrained three-dimensional reaching in Rhesus monkeys

To better understand normative behavior for quantitative evaluation of motor recovery after injury, we studied arm movements by non-injured Rhesus monkeys during a food-retrieval task. While seated, monkeys reached, grasped, and retrieved food items. We recorded three-dimensional kinematics and muscle activity, and used inverse dynamics to calculate joint moments due to gravity, segmental interactions, and to the muscles and tissues of the arm. Endpoint paths showed curvature in three dimensions, suggesting that maintaining straight paths was not an important constraint. Joint moments were dominated by gravity. Generalized muscle and interaction moments were less than half of the gravitational moments. The relationships between shoulder and elbow resultant moments were linear during both reach and retrieval. Although both reach and retrieval required elbow flexor moments, an elbow extensor (triceps brachii) was active during both phases. Antagonistic muscles of both the elbow and hand were co-activated during reach and retrieval. Joint behavior could be described by lumped-parameter models analogous to torsional springs at the joints. Minor alterations to joint quasi-stiffness properties, aided by interaction moments, result in reciprocal movements that evolve under the influence of gravity. The strategies identified in monkeys to reach, grasp, and retrieve items will allow the quantification of prehension during recovery after a spinal cord injury and the effectiveness of therapeutic interventions

An interleukin-33 gene polymorphism is a modifier for eosinophilia in rats

In previous studies, we identified a loss-of-function mutation in the Cyba gene as the primary cause of hereditary eosinophilia in the Matsumoto Eosinophilia Shinshu (MES) rat strain. We also identified a modifier locus for eosinophilia named eos3 in rats. In this study, we examined the interleukin-33 (Il33) gene as a candidate for the eos3 and found a missense nucleotide substitution in the gene, which resulted in a G171S amino-acid substitution in the IL-33 protein. Recombinant IL-33 isoform with the G171S substitution had approximately 50% of activity of normal isoform in NF-kappa B-dependent reporter assay, and reduced bioactivity (similar to 65% of normal) to provoke eosinophilia when injected into mice. In a genetic association study using (ACI x MES) x MES backcross rats, we found that the effects of polymorphic Il33 alleles on blood eosinophil level were manifested only in rats with loss of Cyba function. In these rats, the blood eosinophil level was significantly lower (similar to 50%) in heterozygotes for the ACI allele of Il33 compared with homozygotes for the MES allele. Oddly, however, eosinophilic MES rats had blood IL-33 content below the detectable limits. These results suggest that the Il33 gene polymorphism could be a modifier of eosinophilia in rats. Genes and Immunity (2013) 14, 192-197; doi:10.1038/gene.2013.7; published online 28 February 201