Characterizing emerging features in cell dynamics using topological data analysis methods.

Filament-motor interactions inside cells play essential roles in many developmental as well as other biological processes. For instance, actin-myosin interactions drive the emergence or closure of ring channel structures during wound healing or dorsal closure. These dynamic protein interactions and the resulting protein organization lead to rich time-series data generated by using fluorescence imaging experiments or by simulating realistic stochastic models. We propose methods based on topological data analysis to track topological features through time in cell biology data consisting of point clouds or binary images. The framework proposed here is based on computing the persistent homology of the data at each time point and on connecting topological features through time using established distance metrics between topological summaries. The methods retain aspects of monomer identity when analyzing significant features in filamentous structure data, and capture the overall closure dynamics when assessing the organization of multiple ring structures through time. Using applications of these techniques to experimental data, we show that the proposed methods can describe features of the emergent dynamics and quantitatively distinguish between control and perturbation experiments.

Clinical Outcomes During Admissions for Heart Failure Among Adults With Congenital Heart Disease.

Background Heart failure (HF) admissions in adults with congenital heart disease (CHD) are becoming more common. We compared in-hospital and readmission events among adults with and without CHD admitted for HF. Methods and Results We identified all admissions with the primary diagnosis of HF among adults in the California State Inpatient Database between January 1, 2005 and January 1, 2012. International Classification of Disease (ICD) codes identified the type of CHD lesion, comorbidities, and in-hospital and 30-day readmissions events. Adjusted odds ratio (AOR, 95% CI) was calculated after adjusting for admission year, age, sex, race, household income, primary payor, and Charlson comorbidity index. Of 203 759 patients admitted for HF, 539 had CHD other than atrial septal defect. Compared with patients admitted for HF without CHD, those with CHD were younger, more often male, and had fewer comorbidities as determined by Charlson comorbidity index. On multivariate analysis, CHD patients admitted for HF had higher odds of length of stay ≥7 days (AOR 2.5 [95% CI 2.0-3.1]), incident arrhythmias (AOR 2.8 [95% CI 1.7-4.5]), and in-hospital mortality (AOR 1.9 [95% CI 1.1-3.1]). Also, CHD patients had lower odds of readmission for HF (AOR 0.6 [95% CI 0.3-0.9]), but similar odds of other 30-day readmission events. Complex CHD patients had higher odds of length of stay ≥7 days (AOR 1.9 [95% CI 1.1-3.3]) than patients with noncomplex CHD lesions, but similar odds of all other clinical outcomes. Conclusions Among patients admitted with the primary diagnosis of HF in California, adults with CHD have substantially higher odds of longer length of stay, incident arrhythmias, and in-hospital mortality compared with non-CHD patients. These results suggest a need for HF risk stratification strategies and management protocols specific for patients with CHD.