We have shown that dietary fish oil and pectin (FP) protects against radiation-enhanced colon cancer by upregulating apoptosis in colonic mucosa. To investigate the mechanism of action, we provided rats ( n = 40) with diets containing combination FP or corn cellulose (CC) prior to exposure 1 Gy, GeV/nucleon Fe-ion. All were injected a colon-specific carcinogen, azoxymethane (AOM; 15 mg/kg), 10 17 days after irradiation. Levels colonocyte apoptosis, prostaglandin E 2 (PGE ), PGE 3 ,...

A new class of tissue-equivalent proportional counters has been flown on two space shuttle flights. These detectors and their associated electronics cover a lineal energy range from 0.4 to 1250 keV/microns with multichannel analyzer resolution 0.1 20 5 keV/microns. provide the most complete dynamic highest any technique currently in use. On one mission, detector was mounted Shuttle payload bay another older model mid-deck, thus providing information depth dependence spectrum. detailed...

ABSTRACT: Maintaining an intact nutrient supply in the food system flown on spacecraft is a critical issue for mission success and crew health. Ground‐based evidence indicates that some vitamins may be altered fatty acids oxidized (and therefore rendered useless, or even dangerous) by long‐term storage exposure to radiation, both of which will issues long‐duration exploration missions space. In this study, stability nutrients was investigated samples exposed spaceflight Intl. Space Station...

Single-event energy distributions were measured in a 1.3-micron-diameter site as function of radial distance from the trajectory high-energy iron ions having an about 600 MeV/amu. It was found that beyond distances few micrometers average lineal (mostly single) secondary electrons (delta rays) is order 3 keV/micron. This similar to value medium irradiated by 170-keV photons. The frequency-mean specific for delta rays occurring at large path primary ion exceeds calculated (radial) absorbed...

Brooks, A. L., Bao, S., Rithidech, K., Couch, L. and Braby, Relative Effectiveness of HZE Iron-56 Particles for the Induction Cytogenetic Damage In Vivo.One risks prolonged manned space flight is exposure astronauts to radiation from galactic cosmic rays, which contain heavy ions such as 56Fe. To study effects exposures, experiments were conducted at Brookhaven National Laboratory by exposing Wistar rats high-mass, high-Z, high-energy (HZE) particles using Alternating Gradient Synchrotron...

Research to determine the effects of defined numbers alpha particles on individual mammalian cells is helpful in understanding risks associated with exposure radon. This paper reports first biological data generated using single-particle/single-cell irradiation system developed at Pacific Northwest Laboratory. Using this apparatus, CHO-K1 were exposed controlled 3.2 MeV particles, and responses these irradiations quantified. Chromosomal damage, measured by induction micronuclei, was...

Energy deposition from single events occurring in spherical sites ranging diameter about 50 to 550 $\mu {\rm g} cm}^{-2}$ have been studied by means of a grid-walled proportional counter. Single- and multiple-event spectra medium- low-energy bremsstrahlung are compared those produced by60 Co gamma rays tritium beta rays. From these the dose-mean specific energy number per rad exceeding given event size calculated for various diameter. The relevancy data Kellerer-Rossi theory dual radiation...

SCHNEIDERMAN, M. H., BRABY, L. A., AND ROESCH, W. C. Division Delay after Low X-Ray Doses and Treatment with Cycloheximide. Radiat. Res. 70, 130-140 (1977). Radiation-induced division delay of Chinese hamster ovary cells located in G2, G2 between the cycloheximide X-ray transition points, was measured by mitotic cell selection technique. The yield (number treatment expressed as a fraction control) decreased increasing radiation dose (4.5 to 34 rad). However, either because some were not...

Exploration missions to the Moon or Mars will expose astronauts galactic cosmic radiation and low gravitational fields. Exposure reduced weightbearing independently result in bone loss. However, no data exist regarding skeletal consequences of combining low-dose, high-linear energy transfer (LET) partial weightbearing. We hypothesized that simulated would exacerbate loss animals held at one-sixth body weight (G/6) without exposure. Female BALB/cByJ four-month-old mice were randomly assigned...

Measurements of the cesium-137 content northern Alaskan natives during summer 1964 indicated that adults interior village Anaktuvuk Pass had highest average body burden: 1280 nanocuries cesium-137. This is an increase 200 percent over burden found in 1962 and 100 1963. The greatest a native was 2.4 microcuries cesium-137, but all, 3.0 microcuries, measured non-native living mainly on caribou meat. Sodium-22 samples urine from Eskimos, subsequently Eskimos themselves reindeer

Exposure to high-dose ionizing radiation during medical treatment exerts well-documented deleterious effects on bone health, reducing density and contributing growth retardation in young patients spontaneous fracture postmenopausal women. However, the majority of human exposures occur a much lower dose range than that used oncology clinic. Furthermore, very few studies have examined low-dose integrity results been inconsistent. In this study, mice were irradiated with total-body 0.17, 0.5 or...

The choice of appropriate physical quantities to characterize the biological effects ionizing radiation has evolved over time coupled with advances in scientific understanding. basic hypothesis dosimetry is that energy deposited by initiates all consequences exposure a sample (e.g., DNA damage, reproductive cell death). Physical defined deposition have included dose, measure mean imparted per unit mass target, and linear transfer (LET), distance charged particles traverse medium. primary...

Survival based on colony formation was measured for starved plateau-phase Chinese hamster ovary (CHO) cells exposed to 250 kVp X rays at dose rates of 0.0031, 0.025, 0.18, 0.31, and 1.00 Gy/min. A large dose-rate effect demonstrated. Delayed plating experiments response following a conditioning dose, both using rate Gy/min delays up 48 hr, were also used investigate the alternative repair hypotheses. There is clearly greater change in survival than other experiments. Thus we believe that...

There is growing interest in flying biological experiments beyond low-Earth orbit (LEO) to measure responses potentially relevant those expected during a human mission Mars. Such could be payloads onboard precursor missions, including unmanned private-public partnerships, as well small low-cost spacecraft (satellites) designed specifically for biosentinel-type missions. It the purpose of this paper provide physical cosmic-ray interaction data and related information useful biologists who may...

Electron microbeam experiments are planned or under way to explore in part the question regarding whether bystander effect is a general phenomenon restricted high-LET radiation. Since low-LET radiations scatter more readily compared radiations, identifying cells and assessing potential dose that they may receive will be crucial interpretation of radiobiological results. This paper reports on initial calculations basic information needed for stochastic model penetration energetic electrons...

The tissue-equivalent proportional counter (TEPC)-based dosemeters used on the International Space Station have exceeded their planned useful lives, and are scheduled to be replaced with new units taking advantage of improved technology. original TEPC detectors cylindrical geometry field tubes achieve good energy resolution minimum sensitivity noise created by vibration. inside diameter these is 5.1 cm. developed for this application produce vibration resistance detector isotropic response...

Present methods of measuring energy deposition spectra in irradiated media are due to H. Rossi and his co-workers. The technique involves simulating microscopic absorption sites an irradiated...

Effects on human health from the complex radiation environment in deep space have not been measured and can only be simulated here Earth using experimental systems beams of radiations produced by accelerators, usually one beam at a time. This makes it particularly important to develop instruments that used deep-space missions measure quantities are known relatable biological effectiveness radiation. Tissue-equivalent proportional counters (TEPCs) such instruments. Unfortunately, present...