No abstract

Strain 2 and strain 13 guinea pigs were vaccinated with Mycobacterium bovis BCG and placed on low-protein or protein-adequate diets. Five weeks later all animals were infected by the respiratory route with virulent Mycobacterium tuberculosis H37Rv organisms. Four weeks postchallenge, guinea pigs were skin tested with purified protein derivative and sacrificed. Protein deficiency resulted in significant reductions in body weight and thyimus weight and in an impairment in the ability to control the M. bovis BCG vaccine organisms and to mount delayed hypersensitivity reactions. Protein deficiency also adversely affected the efficacy of the BCG vaccine as demonstrated by the numbers of virulent organisms recovered in spleens and lungs. Strain differences were observed in the number of leukocytes, thymus weight, and the responsiveness of blood lymphocytes to purified protein derivative stimulation. In general, strain 13 guinea pigs responded more dramatically to dietary insult than did their strain 2 counterparts. Protein deprivation completely abolished BCG vaccine protection in the lungs and spleens of strain 13 animals and significantly reduced the protection afforded to strain 2 animals. In both strains, the BCG vaccine protected normally nourished guinea pigs. There was no significant difference between strains with respect to susceptibility to pulmonary infection with virulent mycobacteria. Thus, diet and genetic pedigree each had a significant influence on BCG vaccine efficacy.

Fatty acid analysis Only minor differences in overall relative fatty acid composition were noted among four varieties of potatoes baked by microwave and conventional methods. However, the relative percent total unsaturated fatty acids were consistently lower in the microwave products as compared to conventionally baked potatoes regardless of variety. In addition, the relative percent rrans fatty acids was 2.5-4 times higher in the microwave process compared to the same varieties baked conventiohally.Since the potato is relatively low in lipid material which is present in a greater amount in the skin portion as compared to the interior tuber, entire potatoes were extracted. Approximately 600g (three potatoes) of cooked potatoes were immediately diced into 1L of boiling 80% methanol and refluxed for 10 min. This procedure was used to inactivate lipolytic enzymes that could alter fatty acid composition. It is acknowledged that this process probably resulted in the formation of methyl esters of the free fatty acid present. However, the goal was to methylate all lipid material present and this was accomplished as described below. Preliminary tests had indicated that the use of three potatoes from each lot was sufficient since relatively small standard deviations in relative fatty acid composition were noted. Upon cooling, redistilled diethyl ether was added and the mixture refluxed for 3 hr. The ether layer was separated and evaporated to dryness under a stream of nitrogen. The resulting lipid residue was methylated using commercially available boron trifluoride in methanol and the methylated product subjected to gas chromatographic analysis. Samples of raw potatoes of each variety were treated in the same manner.