Respiratory surfaces are exposed to billions of particulates and pathogens daily. A protective mucus barrier traps and eliminates them via mucociliary clearance (MCC)1,2. However, excessive mucus contributes to transient respiratory infections and to the pathogenesis of numerous respiratory diseases1. MUC5AC and MUC5B are evolutionarily conserved genes that encode structurally related mucin glycoproteins, the principal macromolecules in airway mucus1,3. Genetic variants are linked to diverse lung diseases4-6, but specific roles for MUC5AC and MUC5B in MCC, and the lasting effects of their inhibition, are unknown. Here we show that Muc5b (but not Muc5ac) is required for MCC, for controlling infections in the airways and middle ear, and for maintaining immune homeostasis in the lungs. Muc5b deficiency caused materials to accumulate in upper and lower airways. This defect led to chronic infection by multiple bacterial species, including Staphylococcus aureus, and to inflammation that failed to resolve normally7. Apoptotic macrophages accumulated, phagocytosis was impaired, and IL-23 production was reduced inMuc5b−/− mice. By contrast, in Muc5b transgenic (Tg) mice, macrophage functions improved. Existing dogma defines mucous phenotypes in asthma and chronic obstructive pulmonary disease (COPD) as driven by increased MUC5AC, with MUC5B levels either unaffected or increased in expectorated sputum1,8. However, in many patients, MUC5B production at airway surfaces decreases by as much as 90%9-11. By distinguishing a specific role for Muc5b in MCC, and by determining its impact on bacterial infections and inflammation in mice, our results provide a refined framework for designing targeted therapies to control mucin secretion and restore MCC.

Pneumatosis intestinalis (PI) is characterized by subserosal or submucosal gas-filled cysts of the gastrointestinal tract. The course may be benign or may lead to the need for urgent surgery. Knowledge of the differential diagnosis, course, and treatment modalities are key in providing optimal care to patients who present with this entity. In this article, two cases of "benign" pneumatosis seen at our institution over a one-month period are presented, along with a retrospective review of the English literature from January 1985 to March 1995. Incidence, symptoms, gross and microscopic appearance, radiographic appearance, etiology, differential diagnosis and therapy are reviewed.

No abstract

This study displays trends in the literature over the past 35 years that are often inconsistent with common disorders seen by otologists/neurotologists. Certain diagnoses that are currently being researched less commonly continue to impact patients with the same regularity. Quality of otologic/neurotologic literature has become more reputable with regards to SJR scores.