Validation of an obstructive sleep apnea symptom inventory in persons with multiple sclerosis.

BACKGROUND: Improved screening for obstructive sleep apnea (OSA) could enhance multiple sclerosis (MS) clinical care; yet the utility of current screening tools for OSA have yet to be evaluated in persons with multiple sclerosis (PwMS). OBJECTIVES: The STOP-Bang Questionnnaire is an 8-item screening tool for OSA that is commonly used in non-MS samples. The aim of this study was to assess the validity of the STOP-Bang in PwMS. METHODS: STOP-Bang and polysomnography data were analyzed from n = 200 PwMS. Sensitivity, specificity, positive-, and negative-predictive value (PPV and NPV) were calculated, with receiving operating characteristic (ROC) curves, for each STOP-Bang threshold score, against polysomnography-confirmed OSA diagnosis at three apnea severity thresholds (mild, moderate, and severe). RESULTS: Nearly 70% had a STOP-Bang score of ⩾3% and 78% had OSA. The STOP-Bang at a threshold score of 3 provided sensitivities of 87% and 91% to detect moderate and severe OSA, respectively; and NPV of 84% and 95% to identify PwMS without moderate or severe OSA, respectively. Sensitivity to detect milder forms of OSA was 76%. The NPV to identify persons without milder forms of OSA was 40%. CONCLUSION: The STOP-Bang Questionnaire is an effective tool to screen for moderate and severe OSA in PwMS, but may be insufficient to exclude mild OSA.

Catalytic Nitrene Homocoupling by an Iron(II) Bis(alkoxide) Complex: Bulking Up the Alkoxide Enables a Wider Range of Substrates and Provides Insight into the Reaction Mechanism.

The reaction of HOR' (OR' = di-t-butyl-(3,5-diphenylphenyl)methoxide) with an iron(II) amide precursor forms the iron(II) bis(alkoxide) complex Fe(OR')2(THF)2 (2). 2 (5-10 mol %) serves as a catalyst for the conversion of aryl azides into the corresponding azoarenes. The highest yields are observed for aryl azides featuring two ortho substituents; other substitution patterns in the aryl azide precursor lead to moderate or low yields. The reaction of 2 with stoichiometric amounts (2 equiv) of the corresponding aryl azide shows the formation of azoarenes as the only organic products for the bulkier aryl azides (Ar = mesityl, 2,6-diethylphenyl). In contrast, formation of tetrazene complexes Fe(OR')2(ArNNNNAr) (3-6) is observed for the less bulky aryl azides (Ar = phenyl, 4-methylphenyl, 4-methoxyphenyl, 3,5-dimethylphenyl). The electronic structure of selected tetrazene complexes was probed by spectroscopy (field-dependent 57Fe Mössbauer and high-frequency EPR) and density functional theory calculations. These studies revealed that Fe(OR')2(ArNNNNAr) complexes contain high-spin ( S = 5/2) iron(III) centers exchange-coupled to tetrazene radical anions. Tetrazene complexes Fe(OR')2(ArNNNNAr) produce the corresponding azoarenes (ArNNAr) upon heating. Treatment of a tetrazene complex Fe(OR')2(ArNNNNAr) with a different azide (N3Ar') produces all three possible products ArNNAr, ArNNAr', and Ar'NNAr'. These experiments and quantum mechanics/molecular mechanics calculations exploring the reaction mechanism suggest that the tetrazene functionality serves as a masked form of the reactive iron mono(imido) species.