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Biomedical subjects

B L Cohen

Publications and source records attributed to B L Cohen.

At least 91 records · Page 5Linked to original sources
PubMed1986

A diffusion barrier charcoal adsorption collector for measuring Rn concentrations in indoor air.

Development of a practical detector for collecting Rn by adsorption in charcoal with a time integration of 2 d or more, achieved by use of a diffusion barrier through which Rn enters, is described. The sensitivity is adequate for monitoring Rn levels in houses. It is easily sent and returned by mail, and instructions for use are simple enough for any householder to follow. The cost per measurement is apparently well below that for competitive techniques.

Adsorption↗
PubMed1986

A poll of radiation health scientists.

A sampling of 210 university-employed radiation health scientists randomly selected from the membership lists of the Health Physics Society and the Radiation Research Society was polled in a secret ballot. The results support the positions that the public's fear of radiation is substantially greater than realistic, that TV, newspapers and magazines substantially exaggerate the dangers of radiation, that the amount of money now being spent on radiation protection is sufficient, and that the openness and honesty of U.S. government agencies about dangers of radiation were below average before 1972 but have been above average since then. Respondents give very high credibility ratings to BEIR, UNSCEAR, ICRP, and NCRP and to the individual scientists associated with their reports, and very low credibility ratings to those who have disputed them.

Costs and Cost Analysis↗
PubMed1986

A national survey of 222Rn in U.S. homes and correlating factors.

A survey of 222Rn levels in 453 houses of physics professors from 101 universities in 42 states (plus the District of Columbia) was carried out with 1-y exposures of nuclear track detectors, accompanied by an extensive questionnaire. The geometric mean concentration was 38 Bq/m3 (1.03 pCi/l), the standard deviation was times divided by 2.36, and the arithmetic average was 54 Bq/m3 (1.47 pCi/l). Correlations were studied with age of the house, environs, location of the detector in the house, number of floors in the house, what is beneath the house, integrity of the barrier between the house and the ground, wind conditions, draftiness, construction materials, ventilation, use of gas, and source of water. In general, these correlations were found to be much weaker than expected, indicating that geographical variations are the dominating effect.

Air Pollutants↗
PubMed1986

A generic probabilistic risk analysis for a high-level waste repository.

A generic probabilistic risk analysis (PRA) is developed for high-level radioactive waste buried in a repository. The basic assumption is that an atom of buried waste has the same probability of escape as an atom of average rock at the same depth. Corrections are applied for variation of ground-water flow with depth, and for the fraction of ingested material derived from rock versus from soil. The final result is that we may eventually expect 0.012 deaths/GWe-yr. It is shown that this analysis is a PRA, and that the basic assumption is a conservative one--more likely to overestimate than to underestimate the hazard. This health impact is compared with those from other wastes generated in producing electricity.

Food↗
PubMed1986

Suppression by alpha-fetoprotein of murine natural killer cell activity stimulated in vitro and in vivo by interferon and interleukin 2.

Natural killer (NK) cells are 'spontaneously' cytotoxic cells thought to be involved in surveillance against tumour cells, rejection of virally infected cells, and regulation of haematopoietic stem cell differentiation and antibody synthesis. Fetus-derived alpha-fetoprotein (AFP) has been shown to regulate certain T cell-mediated immune reactions in vitro and in vivo. The lack of NK activity in newborn mice with high endogenous levels of AFP, together with the presence of cells expressing NK surface markers, also suggests that AFP may regulate NK activity. In this study we compared the effects of AFP on spontaneous versus activated murine NK activity. The lytic ability of both freshly prepared splenic NK cells and those arising after incubation for 24 h with interferon, Poly I:C, or T-cell growth factor (TCGF) was not affected by AFP if the latter was present only during the killing phase. However, if AFP was added at the beginning and retained for the duration of the 24-h in vitro lymphokine stimulation, the subsequent NK activity induced by interferon, Poly I:C, and TCGF was found to be significantly suppressed. This inhibition is both dose- and time-dependent. Delayed addition experiments showed that when AFP is present during the first 6 h of in vitro stimulation it will suppress interferon and TCGF-boosted NK activity by 50-80%. The AFP-mediated inhibitory effect on lymphokine-stimulated NK activity is not the result of increased death of effector cells nor, in the case of interferon and polyribonucleotides, of non-specific binding of AFP to the enhancing agents. In vivo injections of Poly I:C or TCGF failed to increase neonatal NK function, while administration of interferon did cause slightly higher levels of NK activity. However, spleen cells from newborn animals cultured for 24 h in the presence of lymphokines resulted in markedly elevated NK function and this in vitro activation could be suppressed by purified fetus-derived AFP. Thus, the in vivo pattern of NK activation in newborns with high endogenous levels of AFP was very similar to that of adult NK stimulation in vitro when exogenous AFP was added.

Animals↗
PubMed1985

Transport of elements from soil to human diet: an alternative approach to pathway analysis.

Transport from soil to human dietary intake is conventionally treated by analyzing the various pathways through uptake by plant roots and transfer from animal feed into milk and meat. An alternative approach is proposed requiring only the average daily human ingestion of each element and its abundance in soil, both readily available for most elements. The two methods are compared quantitatively and give results consistent within a mean factor of four, which is roughly the standard deviation in estimates from the pathway analysis. Neither method gives consistently larger or smaller transfer rates. Each method has important advantages in some applications.

Animal Feed↗
PubMed1985

The origin of I in soil and the 129I problem.

It is widely believed that the I in soil is derived from the I in oceans by evaporating-atmospheric transport-washout by rain over land, rather than from the I in rock when the latter is weathered into soil. Since human I burdens are derived largely from soil by plant root uptake into food, this implies that the specific activity of 129I in the I of human thyroids will be the same as that in the oceans, whereas it would be similar to that in rock (much lower) if the I in soil were derived from weathering of rock as is the case for other heavy trace elements. The bases for the oceanic origin theory are analysed and found not to be in accord with modern data. Recent data shows no correlation between concentration of I in soil and proximity to oceans, which argues strongly against the oceanic origin theory. Some problems with long-distance atmospheric transport are pointed out. It is shown that the balance between I input to soil during soil formation by rock weathering and output from soil by erosion leaves little room for contributions from oceanic sources. It is concluded that only a small fraction of the I in soil is of oceanic origin. Most estimates of very long-term effects of 129I on human health are therefore several times too high.

Food Contamination, Radioactive↗
PubMed1985

Survey of one-year average Rn levels in Pittsburgh area homes.

Radon concentrations averaged over 1 yr were measured in 169 homes selected without regard to factors known to influence Rn levels. The average level was 6.3 pCi/l in basements, 2.4 pCi/l on first floors, and 2.0 pCi/l on second floors; medians were considerably smaller, 2.6, 1.20, and 0.95 pCi/l, respectively. Distributions deviate considerably from log normal in having an excess of very large values and a deficiency of very low values. Levels in upper floors were somewhat lower where the basement was isolated by closed doors than where it was not. Drafty houses had lower Rn levels than less drafty ones. Houses exposed to wind had higher levels than those well sheltered from wind. There was little correlation between Rn concentration and age of the house, indicating that Rn exposures may not have changed appreciably during the past 50 yr; this is important for estimating risks of Rn-induced lung cancer. Houses with forced air heating systems seemed to have higher Rn levels in the upper floors than those with steam or hot water heat. No strong correlations were found between Rn levels and cooking with natural gas, or river vs well-water supplies.

Air Pollutants↗