Spinal and supraspinal mechanisms affecting torque development at different joint angles

Introduction: We examined the neural mechanisms responsible for plantar flexion torque changes at different joint positions. Methods: Nine subjects performed maximal voluntary contractions (MVC) at 6 ankle–knee angle combinations [3 ankle angles (dorsiflexion, anatomic position, plantar flexion) and 2 knee angles (flexion, full extension)]. Neural mechanisms were determined by V‐wave, H‐reflex (at rest and during MVC), and electromyography during MVC (RMS), normalized to the muscle compound action potential (V/M_sup, H_max/M_max, H_sup/M_sup and RMS/M_sup) and voluntary activation (VA), while muscle function was assessed by doublet amplitude. Results: MVC and doublet amplitude were significantly lower at plantar flexion (P < 0.01), while VA was significantly lower at dorsiflexion and full knee extension (P < 0.05). V/M_sup and RMS/M_sup were significantly lower at knee extension (P < 0.01), while H_sup/M_sup was not affected by joint angle. Conclusions: These results indicate that joint positions leading to muscle lengthening produce reduced neural drive, due mainly to supraspinal mechanisms. Muscle Nerve 53 : 626–632, 2016     

Pancreatic necrosis: CT manifestations

Pancreatic necrosis is a potential sequela of acute pancreatitis, which pathologically represents a collection of devitalized tissue. Appropriate therapeutic planning requires definition of this irreversibly damaged gland, the presence of which is not consistently diagnosed on the basis of clinical and laboratory data. Over an 18-month period, 22 patients with pancreatic necrosis were studied by one or more computed tomographic (CT) examinations. Retrospective analysis showed the findings to vary with the developmental stage of the necrotizing process. During the acute phase, there was considerable morphologic overlap of necrosis and pancreatic phlegmon. Typical findings were seen in the subacute and chronic stages and included diffuse enlargement of the gland with largely decreased central density. A thick, smooth surrounding rim produced a characteristic saclike configuration. CT-guided aspiration for culture material was performed in four patients with suspected superinfection. Negative gram stain and culture results in two patients allowed surgery to be performed on a more elective basis.