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PubMed1955

The effect of ionizing radiation on phagocytosis and the bactericidal power of the blood. I. The effect of radiation on migration of leucocytes.

Exposure of rats to 600 r total body radiation did not influence either the rate or the extent of migration of their leucocytes 1 day after irradiation, but did decrease their migration on the 2nd and the 5th postirradiation day. Migration of rat leucocytes was not altered by infection of the animal with M. aureus. Leucocytes of rabbits irradiated with 100 r showed a normal rate and extent of migration. However rabbits exposed to 500 r or 800 r showed depression of leucocyte migration at two postirradiation intervals, on the 3rd to 5th and the 10th to 13th days after irradiation, with normal activity intervening. By the 21st postirradiation day the ability of leucocytes to migrate returned to normal. The effect of radiation on total and differential W.B.C. counts and the relationship of this effect to migration is discussed. The decrease in leucocyte migration could not be ascribed either to leucopenia or to plasma factors.

Animals↗
PubMed1955

The effect of ionizing radiation on phagocytosis and the bactericidal power of the blood. II. The effect of radiation on ingestion and digestion of bacteria.

Rats irradiated with 600 r (total body) showed increased indices of both opsonophagic and surface phagocytosis 2, 12, and 24 hours after irradiation. The indices decreased 72 hours after exposure and returned to normal by the 4th to 5th postirradiation day. Bactericidal power of the blood of irradiated animals was depressed when measured 3 and 6 days after exposure to x-rays. Decomplemented serum from irradiated animals was more bactericidal against M. aureus than decomplemented serum from the control rats. This bactericidal substance was destroyed at 78 degrees C. and was found not to require any complement or specific antibodies for action. Extracts of leucocytes from animals 3 days after irradiation demonstrated no bactericidal activity against M. aureus, while extracts from the control animals or rats 1 day after irradiation were actively bactericidal. The extracts from leucocytes of non-irradiated animals were thermolabile, non-dialyzable, had a pH optimum of 7.5, and were capable of being precipitated by NH(4)SO(4) and of calcium phosphate fractionation. The observed increase in susceptibility of irradiated rats to infection with M. aureus was correlated not only with granulopenia but also with the alteration of the above indicated functions of the granulocytes of the irradiated animals.

Animals↗
PubMed1953

Antigen retention in the rabbit.

Normal and irradiated rabbits were given small doses of I(131) bovine gamma globulin (BGG) and the rates of its loss from their blood were determined. The figures agreed with those of previous reports. 3 to 4 months later, both groups were reinjected with antigen. The control group gave an accelerated (anamnestic) rate of loss, indicative of the immune state. The irradiated group gave a response similar to that given by the control group on primary injection. Rabbits recover from 500 roentgens of x-ray in less than 2 months. Hence, rabbits given BGG soon after irradiation should become immune to this antigen in 2 months if they retain it. Since rabbits reinjected with BGG 3 to 4 months after irradiation did not give an accelerated response, the BGG must not have been retained over the period of time necessary for recovery; i.e., less than 2 months. As the rate of antigen loss is greater in normal than in irradiated animals, normal rabbits will have lost BGG as active antigen prior to the irradiated animals. The amounts of antigen used (0.25 to 0.4 mg./kg.) more nearly approximate the amounts present during disease than have the amounts used in previous studies of antigen retention. The hypothesis that protein antigens are lost as fast or faster than homologous proteins is discussed and the conclusion reached that this is a valid concept.

Animals↗
PubMed1952

Restoration induced by catalase in irradiated microorganisms.

1. E. coli, strain K-12, and B. megatherium 899, irradiated in strict but still undefined physiological conditions with certain heavy doses of ultraviolet light, are efficiently restored by catalase, which acts on or fixes itself upon the bacteria in a few minutes. This restoration (C. R.), different from photorestoration, is aided by a little visible light. 2. At 37 degrees the restorability lasts for about 2 hours after UV irradiation; the restored cells begin to divide at the same time as the normal survivors. 3. C. R. is not produced after x-irradiation. 4. B. megatherium Mox and E. coli, strain B/r show little C. R.; E. coli strain B shows none. None of these three strains is lysogenic, whereas the two preceding catalase-restorable strains are. 5. Phage production in the system "K-12 infected with T2 phage" is restored by catalase after UV irradiation, whereas phage production in the system "infected B" is not. 6. With K-12, catalase does not prevent the growth of phage and the lysis induced by UV irradiation (Lwoff's phenomenon). 7. Hypotheses are discussed concerning: (a) the chemical nature of this action of catalase; (b) a possible relation between C. R. and lysogenicity of the sensitive bacteria; (c) the consequences of such chemical restorations on the general problem of cell radiosensitivity.

Bacteria↗