Dietary RNA Is Important For Immune Functions
The role of dietary sources of nucleotides in immune function: a review
Kulkarni AD; Rudolph FB; Van Buren CT Department of Surgery, University of Texas Medical School at Houston 77030. J Nutr (UNITED STATES) Aug 1994, 124 (8 Suppl) p1442S-1446S
Dietary sources of preformed purines and pyrimidines seem to be important for optimal function of the cellular immune response. It was previously assumed that nucleotides were not needed for normal growth and development, but the results described in this review demonstrate a need for nucleotides in the response to immunological challenges. This effect is likely due to a requirement for preformed pyrimidines for proper development and activation of T cells. The need for sources of preformed nucleotides in defined formulas such as parenteral and enteral formulas and infant formulas is suggested by the studies reviewed below. (19 Refs.)
THE BIOCHEMISTRY AND PHYSIOLOGY OF NUCLEOTIDES
Rudolph FB Institute of Biosciences and Bioengineering, Rice University, Houston, TX 77005. J Nutr (UNITED STATES) Jan 1994, 124 (1 Suppl) p124S-127S
Nucleotides are phosphate esters of nucleosides that contain a sugar linked through a glycosidic linkage with purine and pyrimidine bases. Purine and pyrimidine nucleotides are major components of the cells that make up the monomeric units of DNA and RNA, and they function in all cellular processes. Biosynthesis, inter conversion, catabolism and other aspects of nucleotide metabolism, along with various cellular roles of nucleotides, will be discussed, and the possible use of dietary sources of preformed purines and pyrimidines will be considered. (7 Refs.)
DIETARY NUCLEOTIDES REVERSE MALNUTRITION AND
Pizzini RP; Kumar S; Kulkarni AD; Rudolph FB; Van Buren CT Department of Surgery, University of Texas Medical School, Houston 77030. Arch Surg (UNITED STATES) Jan 1990, 125 (1) p86-9; discussion 90
The requirement of dietary nucleotide sources for maximal helper T-cell function has been demonstrated. The effect of dietary nucleotide restriction was tested during two forms of nutritional stress: starvation and protein malnutrition. In the starvation model, mice were fed chow diet, nucleotide free or nucleotide free supplemented with 0.25% yeast RNA, for at least 4 weeks. The animals were then starved for 5 days, at which time they were killed and mitogen assays were performed using spleen cells. Animals previously maintained on the nucleotide-free diet supplemented with RNA showed a significant increase in spontaneous concanavalin A and phytohemagglutinin-stimulated blastogenesis. Protein malnutrition was induced by feeding Balb/c mice a protein-free diet for 7 to 10 days. These mice then received either the protein-free diet, the nucleotide-free diet, or the nucleotide-free diet supplemented with 0.25% yeast RNA. Popliteal lymph node assays were then performed. The chow diet, nucleotide-free diet, and nucleotide-free diet supplemented with 0.25% yeast RNA led to a restoration of body weight, but only the chow and supplemented diets restored significant popliteal lymph node immune reactivity. These studies using starvation and protein-malnutrition models clearly indicate the nutritional role of nucleotides in the maintenance and restoration of the immune response.
Deprenyl, Vitamin E and Effects on Alzheimer's Disease
A controlled trial of selegiline, alpha-tocopherol, or both as treatment for Alzheimer's disease. The Alzheimer's Disease Cooperative Study
Sano M; Ernesto C; Thomas RG; Klauber MR; Schafer K; Grundman M; Woodbury P; Growdon J; Cotman CW; Pfeiffer E; Schneider LS; Thal LJ Department of Neurology, Columbia University College of Physicians and Surgeons, New York, USA. N Engl J Med (UNITED STATES) Apr 24 1997, 336 (17) p1216-22
Background: There is evidence that medications or vitamins that increase the levels of brain catecholamines and protect against oxidative damage may reduce the neuronal damage and slow the progression of Alzheimer's disease. Methods: We conducted a double-blind, placebo-controlled, randomized, multicenter trial in patients with Alzheimer's disease of moderate severity.
A total of 341 patients received the selective monoamine oxidase inhibitor selegiline (10 mg a day), alpha-tocopherol (vitamin E, 2000 IU a day), both selegiline and alpha-tocopherol, or placebo for two years.
The primary outcome was the time to the occurrence of any of the following: death, institutionalization, loss of the ability to perform basic activities of daily living, or severe dementia (defined as a Clinical Dementia Rating of 3).
Results: Despite random assignment, the baseline score on the Mini-Mental State Examination was higher in the placebo group than in the other three groups, and this variable was highly predictive of the primary outcome (P0.001). In the unadjusted analyses, there was no statistically significant difference in the outcomes among the four groups. In an analyses that included the base-line score on the Mini-Mental State Examination as a covariate, there were significant delays in the time to the primary outcome for the patients treated with selegiline (median time, 655 days; P=0.012), alpha-tocopherol (670 days, P=0.001) or combination therapy (585 days, P=0.049), as compared with the placebo group (440 days).
Conclusions: In patients with moderately severe impairment from Alzheimer's disease, treatment with selegiline or alpha-tocopherol slows the progression of disease.