BIOCHEMICAL CHANGES IN BETA-IRRADIATED EPIDERMIS OF GUINEA PIGS
A dose of about 3000 rep beta radiation was given by contact of Sr/sup 90/ to the clipped skin surfaces of guinea pigs. At varying intervals, 1 to 60 days following exposure, epidermis was separated from underlying dermis and analyzed. In addition to dehydration, irradiated epidermis showed decreases in ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) per mg dry weight. The RNA/DNA ratio increased progressively from 1.22 to 2.04 by the 3rd week and returned to normal by the 60th day following irradiation. There was no significant change in protein N. Increases in total free amino acid, ammonia, and urocanic acid were noted 3 days after exposure, well before any visible evidence of injury. These reached peaks about 15 to 30 days after irradiation when the increments averaged 45% above normal. This rapid, local increase in total free amino acid is noteworthy in view of early amino-aciduria reported in human beings within l2 hr after accidental exposure to 25 to 180 r whole-body irradiation. In contrast to reports of increased taurine and BETA anninoisobutyric acid in the urine of these patients, no increase of these compounds in irradiated epidermis was found. Both BETA -aminoisobutyric acid and BETA alanine (intermediates of thymine and uracil catabolism) were absent in normal and irradiated tissue. Ion- exchange chromatography was used to isolate 22 free amino acids from normal and irradiated epidermis. There was no significant change in the pattern. Each showed a quantitative increase on a dry weight basis, 3, 6 and l5 days postirradiation. The recent finding of ornithine and urea in acidsoluble extracts of guinea pig epidermis indicates that the content of water-soluble N compounds in this rodent tissue is similar to that found in man. There is a decrease in urea content by the 3rd day postirradiation, accompanied by an increase in ammonia. (H.H.D.)
- Research Organization:
- Albert Einstein Medical Center, Philadelphia
- NSA Number:
- NSA-16-032779
- OSTI ID:
- 4780608
- Journal Information:
- J. Albert Einstein Med. Center, Journal Name: J. Albert Einstein Med. Center Vol. Vol: 10
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ALANINE
AMINES
AMINO ACIDS
AMMONIA
BETA PARTICLES
BIOLOGY AND MEDICINE
BODY
BUTYRIC ACID
CHROMATOGRAPHY
DETECTION
DNA
EVAPORATION
GUINEA PIGS
HETEROCYCLICS
IMIDAZOLES
ION EXCHANGE
IRRADIATION
KETONES
MAN
METABOLISM
NITROGEN
NITROGEN COMPOUNDS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC NITROGEN COMPOUNDS
ORNITHINE
PROTEINS
PYRIMIDINES
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
RIBONUCLEIC ACID
SKIN
SOLUBILITY
SOLVENT EXTRACTION
STRONTIUM 90
SULFONIC ACIDS
TAURINE
THYMINE
TISSUES
URACILS
UREA
URINE
UROCANIC ACID
VARIATIONS