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At least 487 records · Page 27Linked to original sources
PubMed2000

Cancer incidence among Norwegian airline pilots.

OBJECTIVES: In this retrospective cohort study, the cancer incidence of commercial pilots was studied to determine whether exposure at work has any influence on the incidence of cancer. METHODS: The cohort was established from the files of the Civil Aviation Administration and included people who had valid licenses as commercial pilots between 1946 and 1994. Basic data about their flight careers were recorded, and exposure to cosmic radiation was estimated. The cohort was linked to the Cancer Register of Norway. The observed number of cases was compared with that expected based on national rates. RESULTS: A group of 3701 male pilots was followed over 70 560 person-years. There were 200 cases of cancer versus 188.8 expected, with a standardized incidence ratio (SIR) of 1.06 and a 95% confidence interval (95% CI) of 0.92-1.22. No significant decreased risk was found for any cancer site. Excess risks were found for malignant melanoma (22 cases SIR 1.8, 95% CI 1.1-2.7) and nonmelanoma skin cancer (14 cases, SIR 2.4, 95% CI 1.3-4.0). For malignant melanoma, there was a significant trend for the SIR by cumulative dose. CONCLUSIONS: For most cancer sites, the incidence among pilots did not deviate from that of the general population and could not be related to block hours of flight time or dose. It seems more likely that the excess risks of malignant melanoma and skin cancer are explained by factors related to life-style rather than by conditions at work.

Adult↗
PubMed2002

Goals of biomedical support of a mission to Mars and possible approaches to achieving them.

The main medical and biological problems associated with a piloted mission to Mars are discussed. Prerequisites for the mission are described, based on our experience with biomedical support of prolonged piloted missions. The most important factors are developing countermeasures against the prolonged effects of microgravity and hypogravity; solving a complex of psychological problems; developing methods to protect against cosmic radiation; and creating effective and reliable life support systems. Some aspects of the likely risks involved in such a mission are also reviewed.

Aerospace Medicine↗
PubMed1993

The effect of space flight on human cellular immunity.

T-lymphocyte responsiveness to mitogens is depressed by an average of 56% in humans (129 subjects) tested during and after space flight. Although there is not yet conclusive evidence of a clinical significance of the test, it is clear that factors of space flight like stress, closed environment and cosmic radiation may affect immune responsiveness. The data obtained from space crews may be compared to the depression seen in subjects undergoing heavy physical stress of head down tilt bedrest. Recently, delayed hypersensitivity [correction of hypersensivity] response was tested on crews of the US space shuttle and of the orbital station MIR by means of a commercially available "skin test". Again, the response was lower in 14 of the 15 subjects tested. In two cases, a strong in flight depression could be related to heavy physical and psychological stress experienced in flight. The data available today are not sufficient to draw conclusions on the hazard of infectious diseases during and after space flight. Although the changes observed never harmed the health of astronauts, immunological changes must be seriously investigated and understood in view of long-duration flights on space stations in an Earth orbit and to other planets like Mars and the Moon.

Adult↗
PubMed2003

Loss of heterozygosity in heavy-ion-induced murine T-cell lymphomas.

One of the important concerns for astronauts in space environment is cancer risk associated with cosmic radiation, including heavy particle carbon-ions. But little information on cancer risk is available. In the present study, we investigated the induction of and cellular and molecular characteristics of T-cell lymphomas of B6C3F1 mice induced by carbon-ions and X-rays. The incidence, the latent period and the surface expression of T-cell differentiation antigens were similar between carbon-ion- and X-ray-induced lymphomas. The size of T-cell lymphomas induced by carbon-ions was significantly smaller than that by X-rays. Molecular analysis indicated that high frequency of loss of heterozygosity (LOH) was found on chromosomes 4, 11, 12 and 19 in both lymphomas. Interestingly, the frequency of LOH on chromosome 11 was much higher, but that on chromosome 12 was lower in carbon-ion-induced T-cell lymphomas than in X-ray-induced ones. These results indicate that mechanistic differences may exist between carbon-ion- and X-ray-induced lymphomagenesis.

Animals↗
PubMed2003

[Carcinogenic effects of single total-body irradiation with accelerated charged particles and gamma rays].

The study deals with the frequency of tumorigenesis in the endocrine glands, skin, soft tissues and internal organs of sexually mature female rats, exposed to accelerated charged particles with low LPE, such components of cosmic radiation as 645 MeV and 9 GeV protons and 4 GeV/nuclon ions of helium. The experiment continued until the animals' natural death. We established a high frequency of endocrine and uterine tumors and a comparatively wide range of localizations in rats which had received sufficient doses of gamma radiation. There were no intestinal or renal tumors, while very few tumors of the skin and soft tissues were detected in unexposed animals.

Animals↗
PubMed2004

[Male fertility in space].

The effects of simulated microgravity on mammalian reproduction were studied using tail-suspended mice, during parabolic flight in a jet plane and in a horizontal clinostat device. In the tail-suspended mouse, which is a model of the shift of body fluid in a microgravity environment, atrophy of the testis and decrease of serum testosterone level were observed. The sperm motility decreased in the muG condition produced by the parabolic flight. There were no statistically significant differences in the efficiency of achieving normal fertilization in vitro, but there was a statistically significant decrease in the number of embryos reaching the morula and blastocyst stages after 96 hours in culture under clinostat rotation. These results suggest that the process of fertilization in vitro is not sensitive to the gravitational vector. However, the possibility exists that microgravity increases the disturbance of spermatogenesis and sperm motility or the frequency of early embryonic lethality. On the possibility of reproduction in space, there are some problems such as the cosmic radiation besides gravity. It is necessary to carry out further experiments in outer space.

Animals↗
PubMed2004

Effect of carbon ions on life span shortening and tumorigenesis in mice.

One of the important concerns for astronauts in space is cancer risk associated with cosmic radiation, including heavy particle ions. But little information on cancer risk is available. We investigated the effect of carbon ions on life span shortening and tumor induction in B6C3F1 mice. The mice were exposed weekly to 0.4 and 2.0 Gy whole-body carbon-ion- or X-ray-irradiation for 4 consecutive weeks. The spectrum of induced tumors varied depending on the dose. The cause of death was thymic lymphomas and liver tumors at high and low dose, respectively. The life span shortening by X-rays was proportional to dose, while carbon ions produced a convex upward relationship. The relative biological effectiveness for the 50% life span shortening was about 1.4. The large effect of carbon ions encourages the study on tumor induction at low doses in the space.

Animals↗
PubMed2004

Lessons learned about spaceflight and cell biology experiments.

Conducting cell biology experiments in microgravity can be among the most technically challenging events in a biologist's life. Conflicting events of spaceflight include waiting to get manifested, delays in manifest schedules, training astronauts to not shake your cultures and to add reagents slowly, as shaking or quick injection can activate signaling cascades and give you erroneous results. It is important to select good hardware that is reliable. Possible conflicting environments in flight include g-force and vibration of launch, exposure of cells to microgravity for extended periods until hardware is turned on, changes in cabin gases and cosmic radiation. One should have an on-board 1-g control centrifuge in order to eliminate environmental differences. Other obstacles include getting your funding in a timely manner (it is not uncommon for two to three years to pass between notification of grant approval for funding and actually getting funded). That said, it is important to note that microgravity research is worthwhile since all terrestrial life evolved in a gravity field and secrets of biological function may only be answered by removing the constant of gravity. Finally, spaceflight experiments are rewarding and worth your effort and patience.

Acceleration↗
PubMed1990

[Irradiation of the population of the West Slovakia Region by atmospheric fallout of 90Sr and 137Cs from 1965 to 1988].

The results of the survey show that as a consequence of the nuclear accident in Chernobyl contamination of foodstuffs with radioactive substances caused in May 1986 and additional irradiation of the population of the West Slovakian region which amounted to approximately 10-20% of the dose load derived from natural sources (cosmic radiation, radioactive substances present in the earth crust, in building materials, etc.). The mean dose load of the population was roughly 8 times higher in 1986 than in 1965, when tests of nuclear weapons had been carried out in the atmosphere and when systematic monitoring of radioactivity in foodstuffs had been implemented in the West Slovakian region. Contamination of the environment due to nuclear weapon tests reached the highest values in 1962-1963 when the dose load of the population can be assumed to have been 2-3 times higher than in 1965. In the locality of the nuclear power plant Jasl. Bohunice contamination of foodstuffs with radioactive substances was in the period of operation of the plant at the level of foodstuff contamination recorded at the reference site.

Accidents↗
PubMed1989

Estimations of risk from environmental asbestos in perspective.

Because very recent data on asbestos in the environment are available, some fairly firm conclusions can now be drawn regarding current exposure to asbestos fibres. If account is taken of occupational exposure data (where past exposure levels were very high indeed, leading to a very significant risk to workers at the time), it is possible to make some reasoned estimates of the risk from ambient air. In the past, there was considerable confusion regarding the degree of risk for both occupational and environmental conditions. In estimating the risk, account needs to be taken, in particular, of the fact that: (a) occupational exposures in the past were frequently higher than reported; (b) asbestosis (a disease only associated with very heavy occupational exposures) would seem to be mechanistically involved in the development of lung cancer associated with asbestos exposure; (c) chrysotile asbestos is now the commonest form of fibre used unlike in the past, when greater quantities of crocidolite and amosite were used, the latter types being much more closely associated with mesothelioma than chrysotile; (d) overall levels of asbestos in environmental ambient air are lower than they used to be; (e) ingested asbestos seems to be associated with a negligible degree of risk as indicated by animal and human studies. The estimated values of risk provided here are smaller than those published some years ago but are similar to those given in very recent key publications. The level of environmental lifetime risk from exposure to airborne asbestos would appear to be about 1 in 100,000 or even lower. Such a level of risk is exceedingly low, and bearing in mind the criteria of both WHO and the Royal Society of London, it would appear to represent an acceptable 'rare-event' extremely low-level risk, like the cancer risk from the cosmic radiation adsorbed when flying across the Atlantic or from eating charcoal broiled meat, or the risk of being killed by lightning.

Air Pollutants↗