Indoor radon maps of the United States

A recently published compilation of average radon levels in 1,729 U.S. counties with standard errors of approximately 20% is used to generate maps exhibiting these results and showing correlations over multicounty areas. Several large areas and numerous smaller areas with high radon levels are identified.

Tests of the linear-no threshold theory for lung cancer induced by exposure to radon

The linear theory used to extrapolate the cancer risk of radon exposure from high levels where direct data are available to low levels encountered in homes is tested by comparing lung cancer rates, m, and average radon levels, r, in numerous U.S. states and counties. It is shown that most problems normally associated with ecological studies do not apply here. The data show a very strong tendency for lung cancer rates, corrected for smoking prevalence (S), to decrease with increasing r, in sharp contrast to the opposite behavior predicted by the theory. It is shown that even a perfect negative r-S correlation cannot explain this discrepancy. Actual r-S correlations are only a few percent. Several other possible explanations for the discrepancy are explored, but none can reduce it by more than about 25%.

Relationship between exposure to radon and various types of cancer

Correlations are studied between average radon levels in 1600 U.S. counties and mortality rates in them from various types of cancer. By far the strongest correlation is with lung cancer, but the sign of the correlation is negative. When smoking prevalence is included in a multiple regression, the large negative correlation between radon and lung cancer is essentially unaffected.

Benefits to a life insurance company from providing radon tests for clients

If a life insurance company provided free radon tests to clients, clients' life expectancies would be extended and profits would thereby be increased. This effect is quantified and it is found that the direct monetary benefits to the company could be substantial. Several subsidiary advantages are also discussed.

High frequency expression of integrated proviruses derived from enhancer trap retroviruses

Since retroviruses integrate preferentially into transcriptionally active loci, the provirus may come under the control of regulatory elements of the gene into which it integrated and thus become a functional tag for that gene. In order to determine the frequency of retroviral integration near active endogenous enhancer elements, a retroviral enhancer trap vector was constructed. Lacking the long terminal repeat enhancer, expression of the neomycin resistance (neo) gene, used as a reporter, is dependent upon endogenous enhancer elements able to activate the long terminal repeat promoter. Infection of murine fibroblast cells indicated that a high proportion of the proviral copies expressed the neo gene. Infection of hematopoietic lines confirmed this high frequency of expression of integrated proviruses. Overall, between 43 and 74% of proviruses integrated into several different cell lines expressed the neo gene. These data suggest that retroviral integration is not only dependent upon transcriptional activity of the genomic target sites, but, more specifically, retroviruses preferentially integrate near active enhancer elements which are often associated with developmentally regulated genes.

How do retinoblastoma tumours form?

The causes of retinoblastoma (RB) can now be described with considerable accuracy, although many details are still unclear. Understanding the genetic changes leading to RB has provided an awareness of general mechanisms of cancer development and progression, previously only suspected. From the basic understanding have come new diagnostic technologies that are now ready to be applied directly to RB patients and their families, and a rational approach, based on this understanding, will help us to develop new therapies that avoid the severe complications of conventional treatment.

Failure of RB1 to reverse the malignant phenotype of human tumor cell lines

In addition to retinoblastoma and osteosarcoma, mutation of both alleles of the RB1 gene occurs frequently in several other types of tumors. In order to evaluate the role of RB1 in cancer, the wild type RB1 gene was introduced into the RB1-deleted breast cancer cell line MDA-468-S4 and retinoblastoma cell lines WERI-Rb1 and Y-79. The RB1 complementary DNA was under control of the inducible murine metallothionein promoter in MDA-468-S4 and the thymidine kinase promoter in the retinoblastoma lines. The protein, p110RB1, produced from the exogenously introduced gene appeared normal by immunoprecipitation, Western blot analysis, and nuclear localization and also showed normal cell cycle-dependent phosphorylation and an ability to bind to E1a protein. No changes in growth rate or morphology were observed in either of the reconstituted cell types. Expression of p110RB1 in MDA-468-S4 did not affect anchorage-independent growth when measured by colony formation in soft agar. Although the ability of WERI-Rb1 cells expressing p110RB1 to form colonies in methylcellulose was reduced, the reconstituted retinoblastoma cell lines formed intraocular tumors in immunodeficient mice with the same efficiency as the RB1-negative parent cell lines and the tumors produced by the RB1-reconstituted cells continued to express p110RB1. These experimental results suggest that the malignant phenotype is little affected by the replacement of p110RB1 and that RB1 is a relatively weak tumor suppressor gene.

Variation of radon levels in U.S. homes correlated with house characteristics, location, and socioeconomic factors

Data are analyzed on measurements of Rn levels in numerous U.S. homes, accompanied by responses to questionnaires. Substantial (but far from complete) bias reduction was accomplished using questionnaire responses, leaving 37,000 measurements in living areas and 33,000 in basements for the analysis. Variables studied included: level with respect to ground where measurement was made, room type, age of house, recent weatherization actions, draftiness, location (urban, suburban, rural), air pollution, market value of house, annual household income, educational attainment of head of household, cigarette smoking, whether the house is rented or owner occupied, and geographic section of U.S. Geometric mean Rn levels were determined for each response to questionnaire items (correlations) and for each pair of responses (cross correlations). Many interesting correlations and cross correlations were found, and their explanation and consequences are discussed.

Hyperphosphorylation of the retinoblastoma gene product is determined by domains outside the simian virus 40 large-T-antigen-binding regions

With the murine retinoblastoma (RB) cDNA, a series of RB mutants were expressed in COS-1 cells and the pRB products were assessed for their ability (i) to bind to large T antigen (large T), (ii) to become modified by phosphorylation, and (iii) to localize in the nucleus. All point mutations and deletions introduced into regions previously defined as contributing to binding to large T abolished pRB-large T complex formation and prevented hyperphosphorylation of the RB protein. In contrast, a series of deletions 5' to these sites did not interfere with binding to large T. While some of the 5' deletion mutants were clearly phosphorylated in a cell cycle-dependent manner, one, delta Pvu, failed to be phosphorylated depsite binding to large T. pRB with mutations created at three putative p34cdc2 phosphorylation sites in the N-terminal region behaved similarly to wild-type pRB, whereas the construct delta P5-6-7-8, mutated at four serine residues C terminal to the large T-binding site, failed to become hyperphosphorylated despite retaining the ability to bind large T. All of the mutants described were also found to localize in the nucleus. These results demonstrate that the domains in pRB responsible for binding to large T are distinct from those recognized by the relevant pRB-specific kinase(s) and/or those which contain cell cycle-dependent phosphorylation sites. Furthermore, these data are consistent with a model in which cell cycle-dependent phosphorylation of pRB requires complex formation with other cellular proteins.

Emerging technologies in the field of healthcare: enhancing the interface to the medical professional

This paper reviews the latest technology either available or currently under development which will enhance the medical professional's ability to interface computer systems. This technology includes bar-coding, graphics, intelligent workstation, and expert system. Whenever possible, examples are given to illustrate the technology.

Ecological versus case-control studies for testing a linear-no threshold dose-response relationship

The two basic problems with ecological studies are (A) individuals studied are not necessarily the individuals who are at risk, and (B) they are very vulnerable to confounding factors. It is shown that where the study is designed to test a linear-no threshold dose-response theory, (A) does not apply. Where the ecological study deals with the average dose and response in a large number of US counties, the available data and computer capability for reducing effects of confounders are so powerful that (B) may be no more important for the ecological than for a case-control study. The migration problem is treated and found to be relatively unimportant.

Analytical- and preparative-scale separation of molecular variants of alpha-fetoprotein by anion-exchange chromatography on Monobead resins

A rapid and reliable purification procedure is described that is useful for both analytical detection and quantitative recovery of milligram amounts of individual molecular variants of mouse alpha-fetoprotein (AFP). The appropriate separation conditions were developed with an analytical-size Mono Q anion-exchange column linked to an automated Fast Protein Liquid Chromatography system. Effective separations of fetal-derived AFP variants was accomplished within 20 min under mild conditions with an L-histidine buffer. Employing the optimal separation conditions established on the Mono Q HR 5/5 column we upscaled the procedure by using a preparative Mono Q HR 16/10 column in order to obtain milligram quantities of each molecular variant of AFP. Seven distinct isomeric forms of AFP could be recovered on the preparative anion exchanger in a highly reproducible manner. Each of the seven protein peaks eluted from the Mono Q column were confirmed to be distinct isoforms of AFP by isoelectric focusing and Western blotting developed with monospecific anti-AFP antisera. This method in its scaled up version offers the benefit of providing milligram quantities of immunochemically pure AFP isomers for structure and function studies.

Isolation and characterization of a distinct immunoregulatory isoform of alpha-fetoprotein produced by the normal fetus

In this report, we examine the functional significance of the molecular microheterogeneity of alpha-fetoprotein (AFP). In doing so, we have taken the direct approach of purifying the naturally occurring isomeric forms of fetal-derived AFP using a preparative anion exchange column linked to an automated fast protein liquid chromatography (FPLC) system followed by parallel testing of each isolated molecular variant for in vitro immunoregulatory activity. The data obtained demonstrate the presence of seven distinct variants of AFP as defined by their retention volumes on FPLC elution profiles, by their pIs on analytical IEF gels, and by Western blot analysis. Molecular mass determination by SDS-PAGE showed each isomer to be equivalent in size to 69,000-dalton native unfractionated AFP molecules. All the immunosuppressive activity of AFP was localized to a single variant representing only 6% of the total composition of native AFP. The immunoregulating isomer termed AFP-1 was the least acidic of the seven isolated variants with a pI of 5.1 and displayed a sialic acid content of 1 mol/mol of protein. The inhibitory activity of AFP-1 could be readily measured on T cell-dependent antibody synthesis, Con A-induced stimulation of Lyt-1+23- thymocyte DNA synthesis, and lymphokine-activated NK cell activity. All other isomers were without effect in these test systems. The immunosuppressive AFP-1 isomer also displayed the strongest growth-promoting influence on cultured bone marrow lymphocytes. There was no correlation between functional activity and degree of expression of sialic acid residues on the AFP molecules. These findings demonstrate that the immunoregulating function of AFP is confined to a distinct and relatively small subpopulation of native AFP molecules and should therefore contribute to the resolution of outstanding questions regarding the structure/function relationship of this onco-fetal glycoprotein.

Gamete intrafallopian tube transfer (GIFT): making laparoscopy more than "diagnostic"

Diagnostic laparoscopy is commonly performed on patients as part of a complete infertility investigation. Recently published protocols have investigated the efficacy of using empiric ovulation induction, intrauterine insemination, or both before beginning in vitro fertilization. Because many patients enrolled in these protocols will be exposed to both ovulation induction and diagnostic laparoscopy, the authors reasoned that it would be more effective to begin ovulation induction at the time of the proposed diagnostic laparoscopy in order to allow gamete intrafallopian tube transfer (GIFT) at the same time. Twenty-five nulliparous patients underwent diagnostic GIFT. There were eight continuing pregnancies in this group (32%). Diagnostic GIFT is a more effective use of the opportunity provided by laparoscopy than diagnostic laparoscopy alone.

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.

Radon concentrations inside public and commercial buildings in the Pittsburgh area

Radon concentrations in ambient air from numerous schools, stores and other public and commercial buildings in the Pittsburgh, PA, area were measured by grab sampling. This is more appropriate than using long-term integrating monitors because of the correlation between times of occupancy and Rn levels. Results indicate that Rn concentrations in these buildings are nearly an order of magnitude less than in homes, and not much higher than outdoors. Variations among sites is also much less than for homes, probably because there is less variability in ventilation and building maintenance practices. Colleges and universities have somewhat higher Rn levels and a larger degree of variability than commercial buildings or hospitals. There was no indication of higher Rn levels in cold weather than in warm weather, or of correlations with the age of the building.

Probability for human intake of an atom randomly released into ground, rivers, oceans and air

Numerical estimates are developed for the probability of an atom randomly released in the top ground layers, in a river, or in the oceans to be ingested orally by a human, and for an atom emitted from an industrial source to be inhaled by a human. Estimates are obtained for both probability per year and for eventual probability. Results vary considerably for different elements, but typical values for total probabilities are: ground, 3 X 10(-3); oceans, 3 X 10(-4); rivers, 1.7 X 10(-4); and air, 5 X 10(-6). Probabilities per year are typically 1 X 10(-7) for releases into the ground and 5 X 10(-8) for releases into the oceans. These results indicate that for material with very long-lasting toxicity, it is important to include the pathways from the ground and from the oceans.

Perspective on genetic effects of radiation

The BEIR -III estimates of genetic effects of radiation are combined with current estimates of radiation from the nuclear-energy industry to derive estimates of the genetic effects of the latter, and the results are put into perspective. All nuclear electricity would have genetic effects equivalent to those of increasing average parental age by 2.6 days (average age of parents shifted by 1.8 yr between 1940-1960), or of men spending 8 hr more per year wearing pants . If 0.5% of the taxes paid by the nuclear industry were used to combat genetic disease by currently available methods, this would avert 160 cases of genetic disease for each case caused by the nuclear industry. Using this money for genetic research would be even more profitable, by a large factor. It is pointed out that the activities of our generation have numerous impacts, both favorable and unfavorable, on future generations that are enormously more important than the genetic effects of our radiation. It is shown that the genetic effects of radiation cannot destroy the human race or create new type monsters. Genetic risks to children of radiation workers and non-radiation workers in the present generation are also treated.

Treatment of prolactinomas with megavoltage radiotherapy

The outcome of treatment of 36 women with prolactinomas using megavoltage radiotherapy combined with interim dopamine agonists (bromocriptine, lysuride, pergolide) was reviewed; 16 of the women showed radiological evidence of a macroadenoma. The most common presenting symptom was secondary amenorrhoea; 26 of the patients had galactorrhoea. In 29 patients who wished to conceive the ovulation rate (as indicated by circulating progesterone concentrations) was 97% and the successful fertility rate 86%. No patient had enlargement of the tumour during pregnancy and there were no complications of radiotherapy. No further tumour enlargement was detected in serial skull radiographs, and an improvement in size of the fossa was noted in 45% of those assessed. When medical treatment was withdrawn a mean of 4.2 years (range 1-11) after radiotherapy in the 27 patients who had completed their families the serum prolactin concentration had fallen appreciably in 26 of them and later became normal in eight. The incidence of growth hormone deficiency rose from 24% of the whole group before radiotherapy to 79% afterwards. Only one patient required thyroxine, and one was receiving gonadotrophin. No patient became deficient in adrenocorticotrophic hormone. A regimen of megavoltage radiotherapy and interim bromocriptine allows women with prolactinomas safely to undergo pregnancy and results in the long term prospect of tumour shrinkage and control of hyperprolactinaemia.

Discounting in assessment of future radiation effects

There is a question as to whether cancer fatalities to be experienced in the distant future as a result of radioactivity produced today should be treated on a par with those experienced now, or whether there should be discounting in analogy with accounting principles for money to be spent in the future. It is shown that recent trends in cancer cure rates justify about an 0.7% per yr discounting. Other rationales for discounting are developed. Money can, and always will be usable for saving lives; setting up a trust fund for future generations to use for this purpose is much more cost-effective than spending money now to reduce their exposure to radiation. The history of interest rates over the past 5000 yr indicates that at least 3% real annual interest can be expected. It may not be necessary to actually set up a trust fund as its purpose is largely accomplished by the decrease in the public debt when money is not spent. The trust fund approach is mathematically equivalent to discounting lives lost in the far future at 3% per yr. As an alternative to the trust fund, money can be invested in biomedical research. It is shown that per dollar spent, this is usually far more beneficial to the health of future generations than protecting them from radiation as that art is currently practiced, and for purposes of cost-benefit analysis, it corresponds to discounting lives lost in the future by a factor of the order of the number of years before they are lost; e.g. the number of lives calculated to be lost 1000 yr from now should be divided by 1000. Implementation of the biomedical research alternative requires only that about 0.1% of taxes from nuclear plants and 0.1% of government support for biomedical research be re-defined as contributions from nuclear plants to this research.

Theory and practice of radon monitoring with charcoal adsorption

Because of interest in charcoal adsorption as an inexpensive radon monitoring technique that may be suitable for mass data collection, the theory of radon adsorption from air by a charcoal bed is developed, giving numerical estimates at all stages. The method is practical down to air concentrations of about 0.1 pCi/l. A simple charcoal bed is limited by the fact that its response is highly sensitive to the time interval before termination of the exposure, but two simple methods of avoiding this problem are developed. Simple methods for determining the diffusion constant for the charcoal being used, and for optimizing the depth of the charcoal bed, are presented.

Applications of ICRP 30, ICRP 23, and radioactive waste risk assessment techniques to chemical carcinogens

Linear, no threshold dose-response relationships at low doses are now accepted by U.S. Government agencies for risk assessment of chemical carcinogens. By application of ICRP30 metabolic models, ICRP23 data on ingestion intake of elements, and radioactive waste risk assessment techniques, it is shown that this predicts large numbers of eventual fatalities because of the high probability for material in the ground to eventually be ingested by humans. For example, a detailed for material in the ground to eventually be ingested by humans. For example, a detailed calculation shows that the cadmium released in U.S. coal burning in one year will eventually cause 20,000 fatal cancers (1000/GWe-yr of electricity production), the imports of cadmium into the U.S. will eventually cause 130,000 fatalities for each year of importing at the current rate, and CdS photovoltaic cells will cause 400 fatalities/GWe-yr.

Radon daughter exposure to uranium miners

Radon exposures to U.S. uranium miners under present conditions average about 1.3 WLM per year approximately or equal to 60 WLM per full working lifetime. This is intermediate between (a) the lowest exposures for which there have been excess lung cancers reported among U.S. miners (120-240 WLM) and (b) average environmental radon exposures (16 WLM), so models based on these two situations are used to estimate expected effects on present uranium miners. In Model A, the loss of life expectancy is 45 days, the SMR (standardized mortality ratio) for lung cancer is 1.10, and the SMR for all causes between ages 18 and 65 is 1.013. In Model B these are 10 days, 1.03 and 1.002 respectively. It is shown that the radon exposures to miners are similar to those to millions of Americans from environmental exposure, and that miner health risks are comparable to those of other radiation workers. Their lung cancer risk from radon is 7-50 times less than their job-related accident mortality risk, and represents 0.7-4% of their total risk in mining. Miners suffer from many diseases with SMR very much larger than that for radon-induced lung cancer, and there are many other occupations and industries with far higher SMR for lung cancer than that from radon exposure to miners.

Effects of ICRP Publication 30 and the 1980 BEIR Report in hazard assessments of high-level waste

ICRP Publication 30 (ICRP30) gives the radiation dose to various body organs in Sv per Bq, which are readily translated into rad per curie ingested for various radioisotopes; the 1980 BEIR Report (BEIR III) gives the risk of fatal cancer per rad of dose to each body organ; the ORIGEN 2 Code gives the curies per tonne of initial uranium fuel in high level waste and in spent fuel. The product of these, Ci/tonne x rad/Ci x risk/rad gives the risk/tonne in terms of fatal cancer doses, if ingested, per tonne of uranium. When the resulting curves are compared with those calculated previously (based on ICRP Publication 2 and the 1972 BEIR Report), the hazard is less for the first century but much more thereafter. The principal sources of this greatly increased hazard is the 100-fold increase in absorption through the gut for 237Np in ICRP 30, plus the high cancer risk from radiation to liver in BEIR III. Some consequences of these changes and some scientific questions relevant to ascertaining their validity are discussed.

Further studies on pituitary and ovarian function in women receiving hormonal contraception

Pituitary and ovarian function was evaluated in women receiving 3 combined oral contraceptive preparations. Basal levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) and gonadotropic responses to gonadotropic releasing hormone (GnRH) were studied in 36 healthy, regularly ovulating women in the early follicular and mid-luteal phases of their menstrual cycle (non-treatment, control). These same women were then divided into 3 groups with 12 volunteers in each. Each group received an oral contraceptive preparation cyclically for 3 months. The preparations were: Nordette (30 microgram ethinyl estradiol and 150 microgram d-norgestrel), Nordiol (50 microgram ethinyl estradiol and 250 microgram d-norgestrel) and Biphasil (50 microgram ethinyl estradiol and 50 microgram d-norgestrel X 11 days and 125 microgram d-norgestrel X 10 days). In the third month of treatment, the tests were repeated on day 21, i.e. after 21 active pills, and on day 28, i.e. after 21 active and 7 inactive tablets. On active therapy, basal FSH and LH were similarly suppressed in the 3 groups. LH had varied responses to a bolus of GnRH, whilst the FSH responses were similar in the 3 groups. After 7 days of inactive tablets, basal FSH and LH had returned to pre-treatment, early follicular phase levels. However, the LH responses to a bolus of GnRH varied in the 3 groups, but again, no differences were noted in the FSH responses. Basal FSH, LH and E2 recovered earlier in the Nordette group during the 7 days of inactive tablets.

Limitations and problems in deriving risk estimates for low-level radiation exposure

Some of the problems in determining the cancer risk of low-level radiation from studies of exposed groups are reviewed and applied to the study of Hanford workers by Mancuso, Stewart, and Kneale. Problems considered are statistical limitations, variation of cancer rates with geography and race, the "healthy worker effect," calendar year and age variation of cancer mortality, choosing from long lists, use of proportional mortality rates, cigarette smoking-cancer correlations, use of averages to represent data distributions, ignoring other data, and correlations between radiation exposure and other factors that may cause cancer. The current status of studies of the Hanford workers is reviewed.