Joe W. Howland

MODIFICATION OF X-IRRADIATION LETHALITY IN MICE BY MICROWAVES (RADAR)

Recent studies suggest that microwaves may alter ionlizing radiation lethality. Alteration of the leukopoietic response and the lethality of X-irradiation was noted in dogs (1). Modification of the lethal effect of y-radiation by microwaves has been observed in rats (2). Small numbers of animals were involved in the studies. The use of a larger number of animals to investigate further the modifying effect of microwaves on X-irradiation injury seems desirable. It would also be worth while to determine if microwave pretreatment in species other than dogs or rats might alter the response to ionizing radiation.

Toxicological and radioprotection studies on S,beta-aminoethylisothiuronium bromide (AET).

AET was moderately toxic when administered in single doses to mice, rats, rabbits, guinea pigs, and cats. When given by intravenous injection, doses ranging from 50 to 450 mg/kg were lethal; by intraperitoneal injection, the lethal range was 350 to 650 mg./kg. Administered orally as a single dose, the lethal range was 250 to 1000 mg/kg. Rats fed dietary levels of 0.1%, 0.3%, and 0.5% for a period of 1 month showed no effects on growth. A 1.0% dietary level produced a moderate depression of growth. An increase in white cell counts was observed at all dietary levels of AET. No histological lesions were found that could be attributed to the ingestion of AET. The protective effects of S, BETA aminoethylisothiuronium - Br - HBr - (AET) against the lethal effects of 594 r of 1-Mev x radiation was tested in 21 dogs, with 14 additional dogs as controls. Data presented indicate failure of this compound to enhance survival or survival rate. (auth)

Attempts to produce localized Shwartzman reaction in seven species of animals.

Conclusions 1. The localized Shwartzman reaction was produced in 62% of 265 New Zealand albino rabbits, using 3 different toxins (a meningococcal agar washings toxin, a partially purified “polysaccharide toxin” prepared from a culture of Serratia marcescens, and a crude Serratia marcescens agar washing toxin). Using these same toxins, localized Shwartzman reactions could not be induced in 15 Macacca mulatta monkeys, 20 mongrel dogs, 16 guinea pigs, 15 Wistar albino rats, 16 small swine (Hormel “Minipigs”), and 4 Toggenburg goats. 2. One post-partum lactating female goat developed a typical “generalized Shwartzman reaction” (i.e. renal cortical hemorrhagic necrosis).

AMINO ACID EXCRETION IN HUMAN PATIENTS ACCIDENTALLY EXPOSED TO LARGE DOSES OF PARTIAL-BODY IONIZING RADIATION. (THE LOCKPORT INCIDENT).

On March 8, 1960, nine civilian electronic technicians were exposed to large doses of partial-body ionizing radiation while servicing a Klystron tube at a military installation in Lockport, New York. The details of this accident, described as the Lockport Incident, including the conditions of exposure, calculations of dosimetry, and clinical symptomatology after the acute exposure, have been described (1). Clinical observations of the patients one year after the radiation accident have recently been reported (2). This report, previously outlined in a preliminary abstract (3), describes the increased urinary excretion of amino acids occurring in these accidentally irradiated individuals during the postexposure period.

The response of dogs to bilateral whole-body Co60 irradiation. I. Lethal dose determination.

The responses of various species after whole-body exposure to external ionizing radiations have received extensive study. A majority of reported investigations concerning canines has been concerned with the manifestations resulting from exposure to X-irradiation. The resulting LDo5(30) values obtained have varied between 300 and 430 r (1-7). More specifically, the mean lethal dose measured in air has been estimated at 315 r with 200-kvp and with 2000-kvp X-ray (2, 7), and a mid-line tissue dose of 252 rep has been reported for 250-kvp X-ray (3). Even though the mean energy of the X-rays used in these studies differed, if the reported ratio between air dose and mid-line tissue dose (3) is applied to the estimated air LD50(3o) (2, 7), a similar mid-line median lethal dose is obtained. The LD50(30) for dogs exposed to a fast neutron flux of approximately 6 X 107 neutrons/cm2-sec has been reported as 289 rep (3). A report of the determination of the LD50(30) for dogs exposed to bilateral, external whole-body Co60 y-radiation has not been found.

THE RESPONSE OF DOGS TO BILATERAL WHOLE-BODY Co

The mid-line tissue LD/sub 50(//sub 30)/ dose for young adult dogs exposed to single bilateral whole-bcdy doses of Co/sup 60/ gamma radiation under the described conditions was 350 r. The radiation syndrome and pathological changes at autopsy were not different from those reported previously. The hematological, mucoprotein, and properdin responses were found to be similar to those for x or neutron irradiation. The incidence of bacteremia was lower than in x irradiated dogs. A correlation between leukocyte change between the seventh and tenth days after irradiation and decedence or survival is discussed. (auth)

sup 60

In experiments with beagles, the LD-50/30 for animals with whole-body exposure to 1,000 kvp x rays is placed at 250 r. The LD-50/30 for upper body exposure to 1,000 kvp x rays is placed at 1,775 r. The gram-roentgen dose required to produce a median lethal dose is raised fourfold by the shielding of the lower portion of the body. (auth)

IRRADIATION. II. PATHOPHYSIOLOGICAL MANIFESTATIONS

The effect of hypothyroidism induced by intravenous injections of I/sup 131/ on antibody production, the anamnestic response, and on antibody decay rate, compared to normal animals, was studied in 63 rabbits. After initial antigenic stimulation, normal animals reached a higher peak titer on an average of 5 days earlier than hypothyroid animals. Antibody half-life in these animals, as measured by time for antibody concentration to fall 50% from peak titer, was 11.4 days in normal compared to 21.3 days in hypothyroid animals. Following a second antigenic stimulation, normal rabbits reached a peak titer in an average of 6.4 days compared to 15 days for hypothyroid animals. The half-life for both groups was measured by determining the rate of disappearance of passively infused antibody. The half-life, thus measured, in normals was 2.4 plus or minus 0.2 days and was 8.8 plus or minus 1.9 days for hypothyroid animals. The time required for serum-tissue equilibration of infused antibody in normals was 1.0 plus or minus 0.00 days compared to 2.3 plus or minus 1.5 days in hypothyroid animals. (auth)