Acute Lung Injury after Instillation of Human Breast Milk into Rabbits' Lungs: Effects of pH and Gastric Juice

Background: The authors compared the lung injury in rabbits that occurred after tracheal instillation of human breast milk (HBM) acidified to pH 1.8 with hydrochloric acid (HCl), HBM at its native pH (7.0), and HBM acidified with gastric juice to pH 1.8 and 3.0.

Methods: The alveolar-to-arterial oxygen tension gradient and dynamic compliance were recorded before and hourly for 4 h after intratracheal instillation of 0.8 ml/kg HBM acidified with HCl (pH 1.8), HBM at its native pH (7.0), HBM acidified with gastric juice (pH 1.8 or 3.0), or 5% dextrose solution acidified with gastric juice (pH 1.8) as a control in 30 adult rabbits. The circulating neutrophil count and phagocyte oxidant activity were determined before and 1 and 4 h after instillation.

Results: The alveolar-to-arterial oxygen tension gradient increased and dynamic compliance decreased significantly in all groups after instillation of HBM compared with baseline values and those in the control group. The severity of the lung injury after instillation of HBM at all pH values (1.8, 3.0, and 7.0) and after acidification with gastric juice or HCl was similar. The circulating neutrophil count increased steadily for 4 h after instillation (P < 0.013), whereas spontaneous phagocyte oxidant burst activity peaked at 1 h (P < 0.007) and returned to baseline by 4 h after instillation.     

Extragastric diseases associated with Helicobacter pylori infection

This paper critically reviews the current literature on extragastric diseases associated with Helicobacter pylori infection, with an emphasis on methodologic issues that complicate interpretation of study findings. This review reveals common study limitations and overall uncertainty that H. pylori infection plays a role in extragastric diseases, although such a role has not been clearly ruled out for specific diseases of relevance. Evidence suggests that anti-H. pylori therapy may lead to improvement of a few extragastric diseases, in particular, idiopathic thrombocytopenic purpura, iron deficiency anemia, and chronic idiopathic urticaria, but the data from randomized controlled trials are insufficient to confirm this beneficial effect; if the benefit of anti-H. pylori therapy for specific diseases is real, it is not clear if it results from removing H. pylori-specific injurious effects, eliminating some other infectious pathogen, or reducing the total infectious burden.