Comparing Presenting Clinical Features in 48 Children With Microscopic Polyangiitis to 183 Children Who Have Granulomatosis With Polyangiitis (Wegener's) : an ARChiVe Cohort Study

OBJECTIVE: To uniquely classify children with microscopic polyangiitis (MPA), to describe their demographic characteristics, presenting clinical features, and initial treatments in comparison to patients with granulomatosis with polyangiitis (Wegener's) (GPA). METHODS: The European Medicines Agency (EMA) classification algorithm was applied by computation to categorical data from patients recruited to the ARChiVe (A Registry for Childhood Vasculitis: e-entry) cohort, with the data censored to November 2015. The EMA algorithm was used to uniquely distinguish children with MPA from children with GPA, whose diagnoses had been classified according to both adult- and pediatric-specific criteria. Descriptive statistics were used for comparisons. RESULTS: In total, 231 of 440 patients (64% female) fulfilled the classification criteria for either MPA (n\u2009=\u200948) or GPA (n\u2009=\u2009183). The median time to diagnosis was 1.6 months in the MPA group and 2.1 months in the GPA group (ranging to 39 and 73 months, respectively). Patients with MPA were significantly younger than those with GPA (median age 11 years versus 14 years). Constitutional features were equally common between the groups. In patients with MPA compared to those with GPA, pulmonary manifestations were less frequent (44% versus 74%) and less severe (primarily, hemorrhage, requirement for supplemental oxygen, and pulmonary failure). Renal pathologic features were frequently found in both groups (75% of patients with MPA versus 83% of patients with GPA) but tended toward greater severity in those with MPA (primarily, nephrotic-range proteinuria, requirement for dialysis, and end-stage renal disease). Airway/eye involvement was absent among patients with MPA, because these GPA-defining features preclude a diagnosis of MPA within the EMA algorithm. Similar proportions of patients with MPA and those with GPA received combination therapy with corticosteroids plus cyclophosphamide (69% and 78%, respectively) or both drugs in combination with plasmapheresis (19% and 22%, respectively). Other treatments administered, ranging in decreasing frequency from 13% to 3%, were rituximab, methotrexate, azathioprine, and mycophenolate mofetil. CONCLUSION: Younger age at disease onset and, perhaps, both gastrointestinal manifestations and more severe kidney disease seem to characterize the clinical profile in children with MPA compared to those with GPA. Delay in diagnosis suggests that recognition of these systemic vasculitides is suboptimal. Compared with adults, initial treatment regimens in children were comparable, but the complete reversal of female-to-male disease prevalence ratios is a provocative finding

Kinetic Coefficients for Mixed Adsorbate Fluids in Narrow Pores

The kinetic coefficients (trace diffusion, mutual diffusion and shear viscosity) of molecules in slit-like and sphero-cylindrical mesoporous systems were studied in terms of the modified lattice-gas model (LGM). The LGM equations were derived for molecules of the mixture having a spherical shape and similar size. A new equation for the velocity of the thermal molecule was used. The theory takes the change in the mechanism of particle migration in different phases into account, viz. from pair collisions for the gas to the overcoming of the activation barrier by thermofluctuation for dense phases. At low mixture densities corresponding to an ideal gas phase, the LGM expression for the mutual diffusion coefficient agrees with the expression of the rigorous kinetic theory of gases. The theory allows the calculation of the kinetic coefficients for the components of binary mixtures in full gas-liquid density areas. The supramolecular structure of the sphero-cylindrical system was modelled by sections with a simple regular geometry (cylindrical and spherical) with the additional inclusion of junctions between different pore sections. The contributions of the near-wall regions caused by the molecule-wall potential to the general appearance of the phase diagrams and the effect of the pore size on the capillary condensation conditions were discussed