Alveolar fractal box dimension inversely correlates with mean linear intercept in mice with elastase-induced emphysema.

Rationale: A widely applicable model of emphysema that allows efficient and sensitive quantification of injury is needed to compare potential therapies.

Objectives: To establish such a model, we studied the relationship between elastase dose and the severity of emphysema in female C57BL/6J mice. We compared alveolar fractal box dimension (D(B)), a new measure which is an assessment of the complexity of the tissue, with mean linear intercept (L(m)), which is commonly used to estimate airspace size, for sensitivity and efficiency of measurement.

A randomized multi-arm repeated-measures prospective study of several modalities of portable oxygen delivery during assessment of functional exercise capacity.

Background: Ambulatory oxygen is an important component of long-term oxygen therapy. Pulse-dose technology conserves oxygen and thus increases the operation time of a portable oxygen system.

Methods: We tested 4 ambulatory oxygen systems (Helios, HomeFill, FreeStyle, and the compressed-oxygen cylinder system we regularly provide for long-term oxygen therapy at our Veterans Affairs hospital) with 39 subjects with stage-IV chronic obstructive pulmonary disease.