Absolute quantification of bovine lactadherin to screen the anti-rotavirus activity of dairy ingredients.

The anti-rotavirus components in breast milk and infant formulas play an important role in the prevention of rotavirus infection. The present study examined whether the levels of phospholipids and bovine lactadherin, which are the major components and proteins of the milk fat globule membrane complex, are useful indices of the anti-rotavirus activity of dairy ingredients used in infant formulas. We compared the anti-rotavirus activity of 2 types of dairy ingredients enriched in the milk fat globule membrane complex: high-fat whey protein concentrate (high-fat WPC) and butter milk powder (BMP), using 50% inhibition concentration (IC50) and linear inhibition activity to determine levels of solid contents, total proteins, phospholipids, and bovine lactadherin. Here, we developed a quantification method using full-length isotope-labeled proteins to measure bovine lactadherin levels in these dairy ingredients. The evaluation of anti-rotavirus activity showed that the difference in IC50 was the smallest when the 2 dairy ingredients were compared at the bovine lactadherin level, among other indices in this study. Additionally, no significant difference was observed between the inhibition linearity of 2 dairy ingredients when evaluating only bovine lactadherin levels. These results indicated that the level of bovine lactadherin was more strongly associated with anti-rotavirus activity than the level of phospholipids. Our results suggest that bovine lactadherin levels can be used to estimate the anti-rotavirus activity of dairy ingredients and can be a criterion used in selecting ingredients for infant formulas.

[A case of polaprezinc-induced pneumonitis].

A 77-year-old man referred to our hospital three months ago presented with dyspnea on effort and chest radiograph abnormalities. Chest computed tomography showed consolidation and irregular thickening of the peribronchovascular interstitium. Bronchoalveolar lavage fluids showed increases in the percentage of lymphocytes and a decrease of the CD4/8 ratio. Transbronchial lung biopsy specimens showed signs of organizing pneumonia. The patient had been given polaprezinc for the treatment of hypogeusia six months before. A lymphocyte-stimulating test for polaprezinc was positive, and so our diagnosis was polaprezinc-induced pneumonitis.