Functional comparison of recombinant acidic mammalian chitinase with enzyme from murine bronchoalveolar lavage.

Acidic mammalian chitinase (AMCase) is an enzyme that selectively degrades the biopolymer chitin. Several chitinase enzymes are utilized by mammals to hydrolyze chitin encountered by inhalation and ingestion. AMCase is distinct from other mammalian chitinases as its activity is retained in strongly acidic conditions (pH <2.0). AMCase expression is induced by antigen-induced mouse models of allergic lung inflammation. This protein has also been implicated in the pathogenesis of asthma although its precise role is poorly defined. We describe a novel way to express and purify active murine AMCase. This material retains properties observed in mouse bronchoalveolar lavage (BAL) fluid with regard to pH preference of activity and its inhibition by cyclic peptide inhibitors argifin and argadin. We found that chitinase in BAL from both antigen-challenged and control animals have similar properties in this regard. This strongly supports the notion the same enzyme (AMCase) gives rise to chitinase activity in both challenged and unchallenged animals. We also describe expression of active human AMCase. The methods described in this paper provide a reliable source of recombinant AMCase that can be utilized to expand understanding of AMCase's role in regulating allergic inflammation.

Food serving size knowledge in African American women and the relationship with body mass index.

OBJECTIVE: To examine serving size knowledge in African Americans and how it is related to body mass index (BMI). DESIGN: Serving size knowledge of food commonly consumed by African Americans was assessed by asking the subjects to select the amount of food considered to be a single serving size by the United States Department of Agriculture and the Food and Drug Administration. Seventeen food items were tested, and the amounts selected were weighed. Body mass index was estimated from measured height and weight. SETTING: Churches. PARTICIPANTS: Ninety-five African American women. MAIN OUTCOME MEASURES: Amount of food selected and BMI. ANALYSES: The amount of food selected was compared with the respective standard serving using the 1-sample Wilcoxon signed rank test. The association between BMI and the amount selected was assessed by logistic regression. RESULTS: The subjects significantly overestimated (P = .001 to .02) serving sizes for cornflakes, apple, watermelon, butter, whole milk, chips, and regular soda. Body mass index was significantly associated with overestimation of cornflakes, butter, cookies, and macaroni and cheese (P = .01 to .03), and the odds ratio for overestimating these food items was 1.46-1.65 times greater per 5-unit increase in BMI. CONCLUSIONS AND IMPLICATIONS: African American women overestimated the serving sizes for 7 of the food items tested, and 4 of the estimates were correlated with BMI. Education regarding serving size is recommended for certain food items.