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The application of 13C-nuclear magnetic resonance spectroscopy to the structural determination of the capsular polysaccharide antigens of Neisseria meningitidis is described. Complete assignments of the spectra of the polysaccharides of serogroups A, B, C, W-135, X and Y were made and were based mainly on previous assignments made for the monomer units of the respective polysaccharides. This technique provides information on all structural aspects of the polysaccharides including composition, mode of linkage, location of O-acetyl substituents, sequence, and conformation. In addition, nuclear magnetic resonance is nondestructive, extremely rapid, and has enormous potential in bacteriological research.

Vitamin A absorption was studied using a water-miscible oral preparation of vitamin A in 19 children ages 1 1/2 to 9 years old with giardiasis and/or ascariasis, both before and after their eradication with appropriate therapy, and in three children without parasites. Marked impairment of vitamin A absorption was noted when administered in a water miscible form in children with 1) combined infection with Giardia lamblia and Ascaris lumbricoides, 2) giardiasis alone, and 3) in a proportion of children with ascariasis alone. In children with both giardiasis and ascarasis eradication of the infections promptly lead to a significant improvement in vitamin A absorption and restored it to normal. Children with giardiasis alone also showed improved vitamin A absorption after therapy. In children with ascariasis alone successful therpay did not lead to a statistically significant improvement.