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Platelet activation was significantly increased in acute ischemic stroke and substantially decreased thereafter. The lesser long-term pharmacodynamic potency of aspirin relative to clopidogrel raises the prospect of the need for more effective antiplatelet agents or a synergistic combination therapy for stroke prevention in the future.

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Summary:Purpose: Reversible cerebral vasoconstriction has been hypothesized to be the etiology of seizures due to hypercalcemia, but angiographic studies documenting vasoconstriction have not previously been available.Methods: We present a 43-year-old woman who had frequent seizures that later evolved to status epilepticus with marked hypercalcemia at the time of the seizures.Results: Magnetic resonance imaging (MRI) of the patient's brain revealed high signal changes in T 2 -weighted imaging, fluorescence-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) over the bilateral occipital and thalamic areas. Cerebral angiography showed blood vessels narrowing, disappearing altogether over the right posterior cerebral artery (PCA) branch, which is compatible with vasoconstriction. Vasoconstriction caused the MRI high signal in the occipital area, which was associated with subsequent periodic lateralized epileptic discharges. The patient's clinical condition improved with management of seizures and hypercalcemia. A second brain MRI 2 weeks later revealed complete resolution of the high-signal lesions. Follow-up cerebral angiography study also showed total recovery of vasoconstriction.Conclusions: The sequence of events suggests the hypothesis that reversible cerebral vasoconstriction may play a role in hypercalcemia-induced seizures. Key Words: SeizureHypercalcemia-Vasoconstriction.Hypercalcemia can cause drowsiness, lethargy, weakness, confusion, and coma, but rarely causes seizures. Neuronal membrane excitability changes (1,2), hypertensive encephalopathy, and vasoconstriction induced by hypercalcemia all have been hypothesized to be the etiologies of seizures (1,3), but vasoconstriction during hypercalcemic seizures has not yet been reported. We present a patient with status epilepticus, caused by breast carcinoma-induced hypercalcemia. Serial brain magnetic resonance imaging (MRI) and cerebral angiography studies showed reversible occipital high-signal abnormalities and transient cerebral vasoconstriction. These findings suggest that vasoconstriction is a contributing factor to hypercalcemia-related seizures. CASE REPORTA 43-year-old right-handed housewife had low back pain and osteoporosis for several years. She was brought to the emergency room (ER) for frequent seizures. The paAccepted January 28, 2004. Address correspondence and reprint requests to Dr. S-L. Lai at Department of Neurology, Kaohsiung Chang-Gung Memorial Hospital, Kaohsiung, Taiwan, 123 Ta-Pei Rd. Niao-Sung Hsiang, Kaohsiung County, Kaohsiung, Taiwan. E-mail: carlos@adm.cgmh.org.tw tient was unconscious, and frequent partial seizures with secondary generalization were noted while she was in the ER. Laboratory evaluation disclosed severe hypercalcemia with serum total calcium of 15.5 mg/dl. Hydration with normal saline at 100 ml/h and magnesium sulfate were administered as treatment for hypercalcemia. Diazepam (DZP) and phenytoin (PHT) were given for the status epilepticus. Physical examination detected a left breast mass,...

We present an approach to overcoming challenges in dynamical dexterity for robots through tunable origami structures. Our work leverages a one-parameter family of flat sheet crease patterns that folds into origami bellows, whose axial compliance can be tuned to select desired stiffness. Concentrically arranged cylinder pairs reliably manifest additive stiffness, extending the tunable range by nearly an order of magnitude and achieving bulk axial stiffness spanning 200-1500 N m −1 using 8 mil thick polyester-coated paper. Accordingly, we design origami energy-storing springs with a stiffness of 1035 N m −1 each and incorporate them into a three degree-offreedom (DOF) tendon-driven spatial pointing mechanism that exhibits trajectory tracking accuracy less than 15% rms error within a (∼2 cm) 3 volume. The origami springs can sustain high power throughput, enabling the robot to achieve asymptotically stable juggling for both highly elastic (1 kg resilient shotput ball) and highly damped ("medicine ball") collisions in the vertical direction with apex heights approaching 10 cm. The results demonstrate that "soft" robotic mechanisms are able to perform a controlled, dynamically actuated task.