Joseph Tabachnick

CELL KINETICS OF EPIDERMAL REPOPULATION AND PERSISTENT HYPERPLASIA IN LOCALLY

The alterations in cell kinetics which result in epidermal repopulation and persistent hyperplasia were studied in guinea pig skin after 3000 rep β-irradiation from a

beta

{}^{90}{\rm Sr}-{}^...

-IRRADIATED GUINEA PIG SKIN.

The ability of anti-inflammatory compounds to suppress an increase in vascular permeability to plasma protein in guinea pig skin following 3000 rep of β-irradiation has been studied. To assess the vascular permeability to plasma protein,125 I-labeled serum albumin was injected into the heart immediately after irradiation, animals were killed 18 hours later, and the amount of125 I-labeled albumin in epidermis and dermis was measured. Anti-inflammatory compounds were given to animals 1 hour before and 9 hours after irradiation. Pronounced suppression of increase in vascular permeability to plasma protein (up to 18 hours) was observed with Cl-583, indomethacin, promethazine HCl, and e-amino-n-caproic acid, the effectiveness decreasing in the order cited, based on the milligrams per kilogram of body weight given. Triamcinolone and chloroquine diphosphate showed slight but insignificant effect. The relation of these results to suggested mediators of the inflammatory reaction was discussed.

Effect of Anti-Inflammatory Compounds on Beta-Irradiation-Induced Increase in Vascular Permeability

We studied the time course of depopulation and repopulation of epidermal cells in guinea-pig skin after β irradiation from a

Cytokinetics of regeneration in beta-irradiated guinea-pig epidermis.

{}^{90}{\rm Sr}-{}^{90}{\rm Y}

Effect of Anti-Inflammatory Compounds on β-Irradiation Induced Radiodermatitis

sealed source. Immediately after clipping, one site on each flank was locally irradiated with 1000, 2200, 3000, or 5000 rad (six sites per animal). The changes in number of basal cells, labeling index (LI), and the appearance of clusters of

Radiation fibrosis of guinea pig skin after. beta. irradiation and an attempt at its suppression with proline analogs

{}^{3}{\rm H}\text{-thymidine-labeled}

Effect of needle puncture and intradermal fluid injection on epidermal cell kinetics of albino guinea-pig skin

basal cells (two or more pulse-labeled cells in direct contact) were observed. Maximum cell loss of recognizable basal cells of 20% on Day 8, 60% on Day 12, and 75% on Day 15 occurred after irradiation with 1000, 2200, and 3000 rad, respectively. The data for 5000 rad was similar to that in 3000-rad-irradiated epidermis. Repopulation (as evidenced by increase in LI and clusters of labeled cells) at all doses began on about the day of maximal cell loss. Regeneration occurred from survivors within the irradiated area after 1000 and 2200 rad, and was completed in 5 days (i.e.,...

Evaluation of section thickness of skin in determining the epidermal labeling index with tritiated thymidine

The effect of several anti-inflammatory agents given per os , intraperitoneally, or topically to alleviate acute radiodermatitis in guinea pig skin following 3,000 or 4,000 rep β-irr

Increased epidermal deoxyribonuclease I activity in

The skins of adult, male albino guinea pigs were irradiated with a dose of 3500-rad ..beta.. rays from a /sup 90/Sr-/sup 90/Y sealed source on 25 x 25-mm flank areas. Abnormal collagen deposition (fibrosis) occurred between the first and fourth months as evidenced by the replacement of the normal thick random whorls of collagen fibers by embryonic-like thin fibers parallel to the hyperplastic epidermis. These histologic changes were confined primarily to about 0.4 mm of upper dermis. By the fourth month and up to 2.5 years postirradiation, there was a decreased content of acid-soluble and -insoluble collagen in the irradiated upper dermis concomitant with an increase in noncollageneous protein. With the exception of occluded arterioles in the lower dermis, there were no obvious chemical or histological changes in collagen of remaining dermis. Injection for 4 months or longer of the proline analogs, DL-3,4-dehydroproline, L-azetidine-2-carboxylic acid, or cis-4-hydroxy-L-proline significantly decreased the small amount of metabolically active soluble collagen but had no effect on the content of insoluble fibrous collagen nor the abnormal deposition of collagen fibers in the upper dermis. The data indicate that the proline analogs are of little or no value in suppressing radiation fibrosis in skin.