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Biomedical subjects

L Messineo

Publications and source records attributed to L Messineo.

16 recordsLinked to original sources
PubMed1983

Age related changes in total DNA and RNA and incorporation of uridine and thymidine in rat brain.

1. Total brain DNA and total brain RNA and the incorporation of thymidine[14C] and uridine[3H] were measured in young and aged rats. 2. From 20 days to the time of sexual maturation, both DNA and RNA levels increase. Total RNA exceeds total DNA at all ages. Comparatively, the ratio of total DNA/RNA is higher in young than in aged animals. 3. The incorporation of thymidine[14C]/g of DNA and of uridine[3H]/g of RNA decreases with age. This decrease is rapid in young animals. After 350 days of age, the incorporation becomes very low. The significance of data is discussed.

Aging↗
PubMed1983

Age-related changes in total DNA and RNA and incorporation of uridine and thymidine in rat liver, kidney and spleen.

Total content of DNA and RNA in liver, kidney and spleen were measured in young and aged rats. At the same time the incorporation of [14C]thymidine, a DNA precursor, and [3H]uridine, an RNA precursor, were also determined. Changes in total organ DNA and RNA correlated with sexual maturation as did incorporation of precursors. Young animals have more DNA per organ relative to RNA, with kidney and spleen DNA showing a decrease between maturity and senescence. However, liver RNA increases with age, a change probably due to decreased catabolism of RNA since [3H]urine uptake decreases. Liver polyploid differentiation, and [14C]thymidine and [3H]uridine uptake, are correlated. In kidney, incorporation of [3H]uridine is inversely related to [14C]thymidine incorporation.

Aging↗
PubMed1981

Temporal changes of [3H]uridine and [14C]thymidine incorporation and total organ DNA and RNA in rat thymus.

Aging at organ, cell and molecular levels is characterized by a variety of deleterious changes. Theoretically, all of these changes must be linked to the primary informational molecule DNA and its ancillary control proteins. The present experiments were done to determine how the rate of nucleotide uptake and/or total quantity of RNA and DNA vary with age. Thymus showed age-related changes in radionucleotide uptake and total quantity of RNA and DNA. The ratio of DNA to RNA is higher in organs of younger animals. Total organ thymus DNA decreased between maturity and senescence. Sexual maturation correlates with DNA and RNA in total organ content or in synthesis.

Aging↗
PubMed1978

Temporal changes in histone acetylation.

The incorporation of tritiated acetate was studied in developing and aging rats. Thymus, liver and serum were collected 30 minutes after injection of acetate. The trichloroacetic acid precipitable histone fraction was then extracted from liver and thymus and its radioactivity determined. Serum and cytoplasmic fractions were also counted. Serum activity declined with age. Thymus histone and cytoplasmic fractions showed a cyclic pattern. Acetylation of liver histones showed a straight line decline to a relatively constant level. The decline in acetylation of liver histones is postulated to be due to repression of acetylation processes and is thought to parallel the change of hepatocytes from a diploid to a polyploid state.

Acetates↗