Influence of Pulsatility and Inflow Waveforms on Tracheal Airflow Dynamics in Healthy Older Adults.

Tracheal collapsibility is a dynamic process altering local airflow dynamics. Patient-specific simulation is a powerful technique to explore the physiological and pathological characteristics of human airways. One of the key considerations in implementing airway computations is choosing the right inlet boundary conditions that can act as a surrogate model for understanding realistic airflow simulations. To this end, we numerically examine airflow patterns under the influence of different profiles, i.e., flat, parabolic, and Womersley, and compare these with a realistic inlet obtained from experiments. Simulations are performed in ten patient-specific cases with normal and rapid breathing rates during the inhalation phase of the respiration cycle. At normal breathing, velocity and vorticity contours reveal primary flow structures on the sagittal plane that impart strength to cross-plane vortices. Rapid breathing, however, encounters small recirculation zones. Quantitative flow metrics are evaluated using time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI). Overall, the flow metrics encountered in a real velocity profile are in close agreement with parabolic and Womersley profiles for normal conditions, however, the Womersley inlet alone conforms to a realistic profile under rapid breathing conditions.

Profile of Indian Patients With Membranous Nephropathy.

INTRODUCTION: The majority of primary membranous nephropathy (MN) cases are no longer considered idiopathic with the discovery of the podocytic autoantigens: phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A (THSD7A). Limited data on PLA2R-related MN in Indians exist in literature, and THSD7A-related MN remains undocumented in this population. We aimed to characterize the baseline PLA2R and THSD7A profile of adult and pediatric membranous nephropathy (MN) in a large Indian single-institution cohort. METHODS: A retrospective analysis of all cases of MN (primary and secondary) between 2014 and 2017 was performed with PLA2R direct immunofluorescence and THSD7A immunohistochemistry on the biopsies and anti-PLA2R enzyme-linked immunosorbent assay (ELISA) on baseline sera. RESULTS: MN constituted 10% of kidney biopsies received in the study period. A total of 216 cases with adequate tissue underwent PLA2R direct immunofluorescence, and 110 of them had available sera for PLA2R ELISA. Combining both testing methods, the prevalence of PLA2R-related primary MN was 72.8%, with moderate concordance between the 2 methods (kappa 0.61). PLA2R was also detected in 16.7% cases of secondary MN, most commonly lupus MN. THSD7A immunohistochemistry performed on 176 cases showed a prevalence of 3.4% in primary MN. One case of lupus MN was also positive for THSD7A. Dual positivity (PLA2R and THSD7A) was noted in 2 cases. The large pediatric cohort tested showed a prevalence of 44% of PLA2R based on tissue testing, whereas 1 case demonstrated THSD7A positivity. CONCLUSION: This study in a large cohort of Indian patients demonstrates prevalence rates of PLA2R- and THSD7A-related MN similar to world literature, including the substantial cohort of pediatric MN. It also confirms variation in MN in the form of outliers within PLA2R (related to tissue and serum testing), dual positivity for PLA2R and THSD7A, and PLA2R/THSD7A-positive secondary MN.