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The paper explores the use of knee stiffness as a parameter in the design of wearable knee assistive devices for augmenting human postural balance. The knee moment-angle relationship is utilized to estimate the quasi-stiffness of the knee. The measurement methods are carefully chosen to be non-invasive without rigid joint attachment to allow observation of unimpeded quiet stance. The relationship between identified biomechanical parameters and computed stiffness estimates is analyzed, and the resulting estimates are employed in the controller design of a stiffness-based knee assistive device. The paper also investigates the biomechanical response of the human body to the modulation of applied stiffness in the presence of varied visual stimuli. This research is a crucial first step toward designing knee-based assistive devices to enhance human postural balance in destabilizing environments.

A 52-year-old woman with a history of frequent inhalational cocaine use was admitted to hospital after presenting to the emergency department with a four-month history of intermittent painful bruises (retiform [...]

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare complication after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) adenoviral vector vaccination. In British Columbia (BC), Canada, a provincial clinical care pathway was developed to guide clinicians in evaluating for VITT among patients who present with thrombocytopenia or thrombosis symptoms within 4 to 28 days after adenoviral vector vaccine exposure. All patients had enzyme-linked immunosorbent assay (ELISA) testing for platelet factor 4 (PF4) antibodies, and all cases with positive PF4-ELISA or d-dimer levels ≥2.0 mg/L fibrinogen equivalent units (FEU) had further testing for platelet-activating PF4 antibodies using a modified serotonin release assay (SRA). Between 1 May and 30 June 2021, 37% of 68 patients investigated for VITT had thrombosis, but only 3 had VITT confirmed by PF4-ELISA and SRA. Platelet counts, d-dimer levels, and ELISA optical density values were significantly different between those with and without VITT. Three patients had thrombocytopenia and thrombosis with d-dimer levels >4.0 mg/L FEU but had negative PF4-ELISA and SRA results. Patients with VITT were treated successfully with IV immunoglobulin, nonheparin anticoagulants, and corticosteroids. Our pathway demonstrated that thrombosis is common among patients investigated for VITT and that PF4-ELISA testing is necessary to confirm VITT in those presenting with thrombosis and thrombocytopenia.

Mutual adaptation is a stabilisation technique by which two unstable systems can reach stability via mutual interactions. It is a technique of great importance and advantage as it eliminates the necessity of a reference model for the systems to follow. The direct approach to mutual adaptation requires both systems to adapt concurrently. Unfortunately, this can lead to instability of the overall system. We propose here to use adaptive switching whilst systems mutually adapt wherein at any given interval of time only one of the systems is allowed to adjust. We provide empirical evidence that shows that such an approach allows broader applicability of the concept of mutual adaptation in that it mitigates a related orthogonality problem, allows a larger class of initial conditions, and improves the rate of convergence, all in the context of second-order systems.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare complication after SARS-CoV-2 adenoviral vector vaccination. In British Columbia, a provincial clinical care pathway was developed to guide clinicians in evaluating for VITT among patients who present with thrombocytopenia or thrombosis symptoms within 4 to 28 days after adenoviral vector vaccine exposure. All patients had enzyme-linked immunosorbent assay (ELISA) testing for platelet factor 4 (PF4) antibodies and all cases with positive PF4-ELISA or D-dimer levels ≥2.0 mg/L fibrinogen equivalent units (FEU) had further testing for platelet-activating PF4 antibodies using a modified serotonin release assay (SRA). Between May 1 and June 30, 2021, 37% of 68 patients investigated for VITT had thrombosis but only 3 had VITT confirmed by PF4-ELISA and SRA. Platelet counts, D-dimer levels, and ELISA optical density values were significantly different between those with and without VITT. Three patients had thrombocytopenia and thrombosis with D-dimer levels >4.0 mg/L FEU but had negative PF4-ELISA and SRA results. Patients with VITT were treated successfully with intravenous immunoglobulin, non-heparin anticoagulants and corticosteroids. Our pathway demonstrated that thrombosis is common among patients investigated for VITT and that PF4-ELISA testing is necessary to confirm VITT in those presenting with thrombosis and thrombocytopenia.

Sehn: Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Lundbeck: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Celgene: Consultancy, Honoraria.

There are occasional pediatric reports of parvovirus B19-associated transient acute hepatitis and hepatic failure. A case of a 34-year-old immunocompetent woman who developed severe and prolonged but self-limited acute hepatitis and myelosuppression following acute parvovirus B19 infection is reported. Parvovirus B19 may be the causative agent in some adult cases of acute non-A-E viral hepatitis and acute liver failure.

Aluminum toxicity first came to attention in the medical literature as a sequela of peritoneal or hemodialysis, where accumulation of aluminum in body tissues results from the use of aluminum-containing dialysate and phosphate binders. The most common clinical presentations of aluminum toxicity include anemia, bone disease, and a syndrome of encephalopathy known as the dialysis encephalopathy sydrome (DES). We present the unique case of a 42-year-old man who developed chronic aluminum toxicity from the intravenous injection of a methadone preparation intended for oral consumption. The methadone solution was concentrated for intravenous injection by heating in aluminum cookware. Experiments performed in our laboratory reproducing this technique, using weakly acidic solutions similar to popular drink mixes, confirmed that significant amounts of elemental aluminum can be leached from aluminum cookware when heated. The patient presented to medical attention with generalized seizures, profound cerebellar dysfunction, myoclonus, and speech apraxia, all of which are characteristic of DES. The peripheral blood film revealed bizarre red cell morphology, with clear features of iron deficiency and prominent coarse basophilic stippling, suggesting impaired iron utilization, which is at least one mechanism of aluminum related hematologic toxicity. A bone marrow biopsy demonstrated extensive osteosclerosis and myelosclerosis, compatible with significant metabolic bone disease. Subsequent investigations revealed a serum aluminum level of 7200 nmol/L, eighteen times the upper limit of normal (400 nmol/L). Chelation therapy with a continuous intravenous infusion of deferoxamine was started, and over a course of ten months the serum aluminum level was reduced to 2390 nmol/L with few side effects. The patient made a significant neurologic recovery and returned to life in the community. This is the first detailed account of the successful use of deferoxamine to chelate aluminum in a patient without dialysis-dependent renal insufficiency. This case also highlights heavy metal exposure as a diagnostic consideration in intravenous substance abusers presenting with multiorgan dysfunction, and the importance of performing a thorough inquiry into injection drug practices when evaluating these patients.