Withdrawal reflexes in the upper limb adapt to arm posture and stimulus location

Introduction: Withdrawal reflexes in the leg adapt in a context‐appropriate manner to remove the limb from noxious stimuli, but the extent to which withdrawal reflexes adapt in the arm remains unknown. Methods: We examined the adaptability of withdrawal reflexes in response to nociceptive stimuli applied in different arm postures and to different digits. Reflexes were elicited at rest, and kinetic and electromyographic responses were recorded under isometric conditions, thereby allowing motorneuron pool excitability to be controlled. Results: Endpoint force changed from a posterior–lateral direction in a flexed posture to predominantly a posterior direction in a more extended posture [change in force angle (mean ± standard deviation) 35.6 ± 5.0°], and the force direction changed similarly with digit I stimulation compared with digit V (change = 22.9 ± 2.9°). Conclusions: The withdrawal reflex in the human upper limb adapts in a functionally relevant manner when elicited at rest. Muscle Nerve 49 : 716–723, 2014     

Prolonged grief following the recent death of a daughter among mothers who experienced distal losses during the Khmer Rouge era: Validity of the prolonged grief construct in Cambodia

This study addressed the validity of the prolonged grief (PG) construct in a Cambodian context. Eighty mothers who lost a young adult daughter stemming from a crowd stampede incident during the annual water festival were interviewed at the six-month post-loss point along with a control group of similarly aged women who were not recently bereaved. Both groups were assessed for PG, PTSD, anxiety, and depression symptoms and well as for the number of distal losses experienced during the Khmer Rouge (KR) regime – knowing that all the women were old enough to have lived through the KR regime. Support for the discriminant validity of PG was shown in a factor analysis in which its core symptoms were distinguished from anxiety, depression, and PTSD symptoms. Also, support was found for its incremental validity as shown in the unique sensitivity of PG in distinguishing the two groups when controlling for the other symptoms. Lastly, a positive relationship was found between the number of distal deaths experienced during the KR regime and PG symptom severity among the group of recently bereaved mothers, providing support for the predictive validity of PG. Implications as well as study limitations are discussed.     

Designing Clinical Trials for Dystonia

With advances in the understanding of the pathophysiology of dystonia, novel therapeutics are being developed. Such therapies will require clinical investigation ranging from exploratory studies to examine safety, tolerability, dosage selection, and preliminary efficacy to confirmatory studies to evaluate efficacy definitively. As dystonia is a rare and complex disorder with clinical and etiological heterogeneity, clinical trials will require careful consideration of the trial design, including enrollment criteria, concomitant medication use, and outcome measures. Given the complexities of designing and implementing efficient clinical trials, it is important for clinicians and statisticians to collaborate closely throughout the clinical development process and that each has a basic understanding of both the clinical and statistical issues that must be addressed. To facilitate designing appropriate clinical trials in this field, we review important general clinical trial and regulatory principles, and discuss the critical components of trials with an emphasis on considerations specific to dystonia. Additionally, we discuss designs used in early exploratory, late exploratory, and confirmatory phases, including adaptive designs.     

Impact of Dietary Aromatic Amino Acids on Osteoclastic Activity

We had shown that aromatic amino acid (phenylalanine, tyrosine, and tryptophan) supplementation prevented bone loss in an aging C57BL/6 mice model. In vivo results from the markers of bone breakdown suggested an inhibition of osteoclastic activity or differentiation. To assess osteoclastic differentiation, we examined the effects of aromatic amino acids on early /structural markers as vitronectin receptor, calcitonin receptor, and carbonic anhydrase II as well as, late/functional differentiation markers; cathepsin K and matrix metalloproteinase 9 (MMP-9). Our data demonstrate that the aromatic amino acids down-regulated early and late osteoclastic differentiation markers as measured by real time PCR. Our data also suggest a link between the vitronectin receptor and the secreted cathepsin K that both showed consistent effects to the aromatic amino acid treatment. However, the non-attachment related proteins, calcitonin receptor, and carbonic anhydrase II, demonstrated less consistent effects in response to treatment. Our data are consistent with aromatic amino acids down-regulating osteoclastic differentiation by suppressing remodeling gene expression thus contributing initially to the net increase in bone mass seen in vivo.