Indirect effects may contribute to the efficacy of radiotherapy by sterilizing malignant cells that are not directly irradiated. However, little is known of the influence of indirect effects in targeted radionuclide treatment. We compared gamma-radiation-induced bystander effects with those resulting from exposure to three radiohaloanalogues of meta-iodoben-zylguanidine (MIBG): [(131)I]MIBG (lo...

Concomitant immunity was evaluated in vivo towards a chemically induced epidermoid carcinoma transplanted in a syngeneic situation. Radiation therapy reversed the declining phase of concomitant immunity associated with tumour progression. The rejection rate of a challenge graft amounted to 82 and 95 per cent, respectively, 2 and 8 days after 25 Gy as compared with 55 and 43 per cent in unirradi...

The multiplication of Rickettsia mooseri in fertile eggs is speeded up and quantitatively increased by single dose x-radiation given either 24 hours before or 48 hours after inoculation. This effect is noted at all dosage levels studied, ranging from 100 to 1500 r. The rickettsiostatic effects of high incubation temperature (40 degrees C.) and of streptomycin are neutralized by radiation, but t...

Radon is a naturally occurring tasteless, odourless gas. It is found everywhere, usually at negligible concentrations. It can enter buildings from porous soil and rock and usually dissipates harmlessly into the atmosphere (1). However, in enclosed spaces, such as houses, it can accumulate and pose health hazards, specifically an increased risk of lung cancer (2,3). On average radon contributes ...

Positrons are accumulated within a Penning trap designed to make more precise measurements of the positron and electron magnetic moments. The retractable radioactive source used is weak enough to require no license for handling radioactive material, and the radiation dosage 1 m from the source gives an exposure several times smaller than the average radiation dose on the earth's surface. The 10...

Exposure of Venezuelan equine encephalomyelitis (VEE) virus (at -70 C) to 6 x 10 r gamma-radiation (Co) resulted in loss of lethality for young adult mice and guinea pigs, and loss of capacity to produce plaques or cytopathic effects in tissue culture. The suckling mouse was more sensitive for detecting live virus in radiated suspensions than was the adult mouse or guinea pig. Live virus was de...

(1) Pettit, E. “Ultra-violet Solar Radiation.” Mount Wilson Contr., N ~ . 98. prp,.. Nat. Acad. sc., 13, 380-387, 1927. (2) Pettit, h. Measurements of Ultra-Violet Solar Radiation.” Mount Wilson Contr., No. 445; Astrophysical Jour., 75, 185-221, 1932. (3) .Davis, G. E. “Instruments for Radiometric and Radiobiological Investigations a t the Desert Sanatorium and Institute of Research, Tucson, Ar...

Irradiation induces bone injury by generating free radicals that adversely affect the microenvironment for Mesenchymal stem cells (MSCs) and damages bone marrow blood vessels. We wished to investigate the efficacy of antioxidant administration in protecting stem cell microenvironments and promoting bone marrow vasculature recovery after radiation treatment. The antioxidant ascorbic acid was adm...

We present an interim report on Chandra HRC-S calibration observations of Vega, an Xray–dark and UV-bright star. The purpose of the observations is to monitor the UV response of the detector, and recently it has acquired further importance as a means to track the effects of increased radiation dosage on the UV/ion-shield of the detector. We find no conclusive evidence that leaving the HRC door ...

In this work, we present an algorithm to perform automatic segmentation, feature extraction and dosage classification of images derived from a novel organotypic angiogenesis assay developed to assess the effects of ionising radiation in the mouse heart. The images presented very different conditions of illumination and conditions of density and shapes of cells. The algorithm consists of a pipel...