Clonally heritable gene expression imparts a layer of diversity within cell types

Cell types can be classified according to shared patterns of transcription. Non-genetic variability among individual cells of the same type has been ascribed to stochastic transcriptional bursting and transient cell states. Using high-coverage single-cell RNA profiling, we asked whether long-term, heritable differences in gene expression can impart diversity within cells of the same type. Studying clonal human lymphocytes and mouse brain cells, we uncovered a vast diversity of heritable gene expression patterns among different clones of cells of the same type in vivo. We combined chromatin accessibility and RNA profiling on different lymphocyte clones to reveal thousands of regulatory regions exhibiting interclonal variation, which could be directly linked to interclonal variation in gene expression. Our findings identify a source of cellular diversity, which may have important implications for how cellular populations are shaped by selective processes in development, aging, and disease. A record of this paper's transparent peer review process is included in the supplemental information.

Arteriovenous perfusion with the pulmonary assist membrane oxygenator

The feasibility of employing a recently developed pulmonary assist membrane oxygenator for partial respiratory support in arteriovenous perfusion was studied using small mongrel dogs rendered hypoxic by oxygen depression. The unit is employed along with the conventional ventilation techniques (such as CPAP and PEEP) when the latter alone cannot maintain adequate gas exchange in the lung. The results indicate that poorly oxygenated arterial blood can be upgraded to life-sustaining levels when the bypass flow rate through the oxygenator is in the range of 18-33% of the total cardiac output. No cardiovascular derangements were noted at these arteriovenous flow rates for perfusion periods of four to six hours. The present results demonstrate the feasibility of providing partial support to pulmonary function using the pulmonary assist membrane oxygenator.