Correction to: Hydroxychloroquine dosing in immune-mediated diseases: implications for patient safety.

The given and family name of a co-author R. Adams Dudley was swapped in the published article. The correct given name is R. Adams and the family name is Dudley.

Hydroxychloroquine dosing in immune-mediated diseases: implications for patient safety.

Evidence suggests that hydroxychloroquine (HCQ) retinal toxicity is more common than previously thought. Adhering to careful weight-based dosing can significantly reduce the risk of this adverse event and is recommended in recent guidelines. We used electronic health record data from a large health system to examine HCQ dosing over a 5-year period and identify risk factors associated with higher dosage of HCQ. We constructed a longitudinal, retrospective cohort of patients with HCQ prescriptions (1681 patients with 3490 prescribing events) between 2012 and 2016. We measured HCQ dosing patterns relative to guidelines (<6.5 and <5.0 mg/kg) over time and used longitudinal multivariate mixed effects logistic regression to identify sociodemographic, clinical and health system factors associated with receiving higher than recommended doses of HCQ. The proportion of patients receiving doses above 6.5 mg/kg decreased from 12% in 2012 to 7% by 2016. Similarly, the proportion of patients with doses above 5.0 mg/kg fell from 38% in 2012 to 30% in 2016. Low body weight (<68 kg) was strongly associated with receiving doses of HCQ above 6.5 mg/kg across all time points, even after adjusting for other factors (odds ratios ranging from 13.2 to 21.0). Although the proportion of patients receiving higher than recommended HCQ doses has declined over a period of 5 years, a substantial number of individuals remain at increased risk for toxicity. Given the widespread use of HCQ in immune-mediated diseases, our study suggests that interventions aimed to ensure appropriate dosing are warranted to improve patient safety.

Abnormal platelet aggregation in idiopathic pulmonary arterial hypertension: role of nitric oxide.

Idiopathic pulmonary arterial hypertension (IPAH) is a rare and progressive disease. Several processes are believed to lead to the fatal progressive pulmonary arterial narrowing seen in IPAH including vasoconstriction, cellular proliferation inflammation, vascular remodeling, abnormalities in the lung matrix, and in situ thrombosis. Nitric oxide (NO) produced by NO synthases (NOS) is a potent vasodilator and plays important roles in many other processes including platelet function. Reduced NO levels in patients with IPAH are known to contribute to the development of pulmonary hypertension and its complications. Platelet defects have been implied in IPAH, but original research supporting this hypothesis has been limited. Normal platelets are known to have NOS activity, but little is known about NOS expression and NO production by platelets in patients with IPAH. Here we characterized the phenotype of the platelets in IPAH and show a defect in their ability to be activated in vitro by thrombin receptor activating protein but not adenosine diphosphate. We also show that endothelial NOS (eNOS) levels in these platelets are reduced and demonstrate that NO is an important regulator of platelet function. Thus reduced levels of eNOS in platelets could impact their ability to regulate their own function appropriately.

O-linked beta-N-acetylglucosamine (O-GlcNAc) regulates stress-induced heat shock protein expression in a GSK-3beta-dependent manner.

To investigate the mechanisms by which O-linked ß-N-acetylglucosamine modification of nucleocytoplasmic proteins (O-GlcNAc) confers stress tolerance to multiple forms of cellular injury, we explored the role(s) of O-GlcNAc in the regulation of heat shock protein (HSP) expression. Using a cell line in which deletion of the O-GlcNAc transferase (OGT; the enzyme that adds O-GlcNAc) can be induced by 4-hydroxytamoxifen, we screened the expression of 84 HSPs using quantitative reverse transcriptase PCR. In OGT null cells the stress-induced expression of 18 molecular chaperones, including HSP72, were reduced. GSK-3ß promotes apoptosis through numerous pathways, including phosphorylation of heat shock factor 1 (HSF1) at Ser(303) (Ser(P)(303) HSF1), which inactivates HSF1 and inhibits HSP expression. In OGT null cells we observed increased Ser(P)(303) HSF1; conversely, in cells in which O-GlcNAc levels had been elevated, reduced Ser(P)(303) HSF1 was detected. These data, combined with those showing that inhibition of GSK-3ß in OGT null cells recovers HSP72 expression, suggests that O-GlcNAc regulates the activity of GSK-3ß. In OGT null cells, stress-induced inactivation of GSK-3ß by phosphorylation at Ser(9) was ablated providing a molecular basis for these findings. Together, these data suggest that stress-induced GlcNAcylation increases HSP expression through inhibition of GSK-3ß.

A comparison of the sensitivity, specificity, and molecular weight accuracy of three different commercially available Hyaluronan ELISA-like assays.

Hyaluronan (HA) is a glycosaminoglycan found in the extracellular matrix and ranges from several thousand to millions of daltons in size. HA has importance in various pathological conditions and is known to be elevated in several diseases. Three commonly used, commercially available HA enzyme-linked immunosorbent assay (ELISA)-like assays (from Corgenix, Echelon and R&D) were compared on the basis of accuracy, sample variability and ability to measure a range of HA sizes. The Corgenix HA ELISA-like assay displayed the lowest intra-assay variability [coefficient of variation (CV) = 11.7 ± 3.6%], followed by R&D (CV = 12.3 ± 4.6%) and Echelon (CV = 18.9 ± 9.2%). Interassay variability was also lowest for the Corgenix assay (CV = 6.0%), intermediate for the Echelon assay (9.5%) and highest for the R&D assay (CV = 34.1%). The high interassay variability seen for the R&D assay may have been due to the effect of dilution, since the dilution-independent interassay variability was 15.5%. The concentration of the standard HA was overestimated by the Echelon assay by 85% and underestimated by the R&D and Corgenix assays by 34 and 32%, respectively. The Echelon HA ELISA-like assay was the most effective at measuring all sizes of HA tested (2 MDa and 132, 66 and 6.4 kDa), whereas the Corgenix and R&D assays were unable to detect 6.4 kDa HA. These findings suggest that the Echelon HA ELISA-like assay is better suited for size-sensitive HA measurements but has a relatively high variability. The Corgenix and R&D HA ELISA-like assays have low variability and high accuracy but are not suitable for detecting low-molecular-weight HA.

Nitric oxide deficiency in pulmonary hypertension: Pathobiology and implications for therapy.

Nitric oxide (NO) is a diffusible gas with diverse roles in human physiology and disease. Significant progress in the understanding of its biological effects has taken place in recent years. This has led to a better understanding of the pathobiology of pulmonary hypertension (PH) and the development of new therapies. This article provides an overview of the NO physiology and its role in the pathobiology of lung diseases, particularly PH. We also discuss current and emerging specific treatments that target NO signaling pathways in PH.

A feasibility study using interactive graphic art feedback to augment acute neurorehabilitation therapy.

BACKGROUND: Interactive arts technologies, designed to augment the acute neurorehabilitation provided by expert therapists, may overcome existing barriers of access for patients with low motor and cognitive function. OBJECTIVES: Develop an application prototype to present movement feedback interactively and creatively. Evaluate feasibility of use within acute neurorehabilitation. METHODS: Record demographics and Functional Independent Measure™ scores among inpatients who used the technology during physical, occupational or recreational therapy. Record exercises performed with the technology, longest exercise duration performed (calculated from sensor data), user feedback, and therapist responses to a validated technology assessment questionnaire. RESULTS: Inpatients (n = 21) between the ages of 19 and 86 (mean 57 ± 18; 12 male/9 female) receiving treatment for motor deficits associated with neuropathology used the application in conjunction with occupational, recreational, or physical therapy during 1 to 7 sessions. Patients classified on the Functional Independence Measure™ as requiring 75%+ assistance for cognitive and motor function were able to use the interactive application. CONCLUSIONS: Customized interactive arts applications are appropriate for further study as a therapeutic modality. In addition to providing interactivity to individuals with low motor function, interactive arts applications might serve to augment activity-based medicine among inpatients with low problem-solving and memory function.