Radiats Biol Radioecol
March 2000
The ozone layer depletion evokes the increase of solar UV-B radiation intensity and corresponding reductions of growth (height, leaf area, fresh and dry weight), photosynthetic activity and flowering in higher plants. Competitive interactions also may be altered indirectly by differential growth responses. The UV-B-sensitivity of plants varies both among species and among cultivars of a given species.
View Article and Find Full Text PDFCorrelations between effective UVR doses for induction of skin erythema, premature aging and cancer, immunosuppression, vitamin D photobiosynthesis and cataract on the one hand and various ethnic signs, sex, age and metabolic states of organism on the other were considered. Individual UV sensitivity by all criteria mentioned with the exception of immunosuppression and cataract is conditioned by specificity of melanin and DNA metabolism, and risk of skin cancer incidence besides that depends of immune system state. Values of risk factors for UVR effects mentioned incidence in individuals of different sex and age with various ethnic and metabolic conditions are presented.
View Article and Find Full Text PDFRadiats Biol Radioecol
July 1998
Information on possible human health-changes associated with stratosphere ozone depletion and amplification factor (% increase of the stick rate by 1% decrease of ozone) values for acute (erythema, keratitis, cataract, immunosuppression) and chronic (skin cancer, cataract) effects of natural UV-radiation was analysed. Amplification factor (AF) values for acute UV-effects increase with degree of ozone depletion. For degrees less than 12.
View Article and Find Full Text PDFAviakosm Ekolog Med
July 1998
UVR effects on human health are considered. The critical organs for UVR are skin, eye, and the immune system. In the skin, UVR can induce erythema, tanning, vitamin D photosynthesis, premature aging, and cancer.
View Article and Find Full Text PDFVopr Kurortol Fizioter Lech Fiz Kult
June 1998
Reflection spectra of human skin of various ethnic types in the range of 370-790 nm were measured and analyzed. Correlation between reflection coefficients and minimal erythemal doses was estimated. The formula has been devised which is suitable for defining minimal erythemal doses both for open and closed parts of the body irrespective of pre-exposition to sun radiation.
View Article and Find Full Text PDFQuantitative analysis of threshold limit levels of UV-irradiation in the workroom environment established in USA, Netherlands and Russia was made. Comparison of its results with modern information about effective doses and action spectra of UV-radiation biological action allowed to reveal essential differences in the approach to rate setting and in some cases presence of internal contradictions and exceeding of threshold limit levels of UV irradiation above biologically effective values. The possibility of workroom UV standards utilisation for regulation of nature UV-radiation exposures was considered.
View Article and Find Full Text PDFIzv Akad Nauk Ser Biol
January 1997
Hairless mice of strain HRS were exposed to vertical UV-B-irradiation (280-320 nm) at daily doses of 1 or 2 kJ/m2 (biologically effective doses 200 and 400 J/m2) five days a week for 13 and 6 weeks. As the length of exposure increased, the abundance of automicroflora of the dorsal skin first decreased, then exceeded the control value, was normalized, and remained at the normal level until the end of the experiment. The rates of effect appearance and disappearance, just as its amplitude, increased with the daily doses.
View Article and Find Full Text PDFVopr Kurortol Fizioter Lech Fiz Kult
January 1997
Natural ultraviolet radiation spectral irradiance at the terrestrial zones of various latitudes and altitudes was measured. On this basis biologically effective intensities and times for induction of erythema, photo-keratoconjunctivitis, cataract, immunosuppression and skin pigmentation after acute UV-irradiation were calculated. Skin cancer, cataract and vitamin D deficit risk values dependences on intensity and dose of prolonged UV-exposure were considered.
View Article and Find Full Text PDFUsp Fiziol Nauk
January 1996
Human and animal health effects of UVR are considered. At the cellular level UVR have been observed to cause changes in the cell division and/or differentiation, the loss of specialized functions, mutations, transformation and death. Most of these effects occur via mechanism that involves DNA damage and induction of pyrimidine dimers.
View Article and Find Full Text PDFRadiats Biol Radioecol
November 1995
Human and animal health effects of UV-radiation are considered. Action spectra and biologically effective doses for UV-induced erythema, keratoconjunctivitis, cataract, skin cancer and immunosuppression are presented. Admissible doses of UV-irradiation with regard to damage to skin and eye, recommended in some foreign countries, are discussed.
View Article and Find Full Text PDFRabbits were exposed to vertically directed UV-B radiation (280-320 nm) 5 days a week during 10 months with daily dose 6.5 J/m2 (biological effective daily dose 0.83 J/m2).
View Article and Find Full Text PDFKosm Biol Aviakosm Med
January 1992
Rabbit eyes were exposed to UV-B-radiation (= 280-320 nm) with a biologically effective dose of 1300 J/m2. The exposure inhibited the ability of animals to perceive motion and react to velocity changes. The limit velocity of adequate response and the critical velocity of nystagmus failure measured electrooculographically made 15% and 30% on day 2 and day 9 after exposure and returned to the norm only on day 20 after irradiation.
View Article and Find Full Text PDFThe effect of UV-B-radiation of high intensity on terrestrial microorganisms, aqueous ecosystems, and plants is described. The effect of UV-B-radiation on humans and animals is discussed and quantitative evaluation of ozone layer destruction is given. It is indicated that potential changes will grow continuously, producing a significant effect on the biosphere.
View Article and Find Full Text PDFMale and female nude mice of the HRS strain were exposed to single UV-B-irradiation with biologically effective doses of 1.0 and 1.4 kJ/m2 at an intensity of 0.
View Article and Find Full Text PDFThe retinal epithelium, bone marrow and spermatogenic epithelium of mice exposed for 30 days to constant magnetic fields of 1.6 T were examined cytologically. During and after exposure the retinal and bone marrow epithelium showed no biologically significant deviations from normal.
View Article and Find Full Text PDFIzv Akad Nauk SSSR Biol
September 1983
The mitotic index, frequency of chromosomal aberrations, and the cell count in the bone marrow, corneal and intestinal epithelium of mice exposed for one hour to a magnetic field (MF) with a period of 30 sec and intensity of 2.9-127 kOe have been examined. The mitotic activity of the corneal epithelium was inhibited during the exposure, and began to recover immediately after its terminations.
View Article and Find Full Text PDFKosm Biol Aviakosm Med
January 1980
The effect of an infralow frequency magnetic field of 3-127 kOe applied for 1 hr on mitotic activity, frequency of chromosomal aberrations and number of bone marrow cells of mice was studed. The exposure of mice to fields of 3 and 8 kOe stimulated and to fields of 54 and 127 kOe inhibited mitotic activity. No increase in the frequency of aberrant mitoses in bone marrow cells was noted.
View Article and Find Full Text PDFThe influence of an infralow-frequency magnetic field (IMF) with intensity 3-127 k0e for 1 h on the mitotic activity, frequency of chromosome aberrations, and number of corneal epithelial cells of mice was studied. It was shown that the changes in mitotic activity that arise can be explained by a reversible inhibition of cell division at late stages of the mitotic cycle and synchronous entry into mitosis after the removal of this inhibition. The nature of the dependence of the effect on the intensity of the IMF is evidence of a difference in its molecular mechanisms in the region of high and ultrahigh intensities.
View Article and Find Full Text PDFA study was made of the 0.5--24 hour effects of the stable magnetic field (SMF), with 9.9--42.
View Article and Find Full Text PDFDuring a prolonged (15 days) exposure to a constant magnetic field of 1000 oersted two-phasic changes in the mitotic index of the corneal epithelium and bone marrow were noted. The initial decrease of the index was replaced with its recovery and hyperregeneration. The cell count of the tissues varied insignificantly and rapidly returned to normal when the field was switched off.
View Article and Find Full Text PDFThe mitotic index of mouse corneal epithelium was studied during and after 0.5-- 24 hours exposures to 9.9-39.
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