[Plant reaction to elevated ultraviolet irradiation: potential impacts of stratospheric ozone depletion].

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.

[The factors of individual sensitivity to ultraviolet radiation].

Correlations 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.

[Biomedical and economic consequences of stratosphere ozone depletion].

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.

[Ultraviolet radiation as a risk factor on the Earth and outer space].

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.

[The use of human skin reflectance spectra for the quantitative assessment of individual sensitivity to ultraviolet radiation].

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.

[A comparative analysis of the existing standards for exposure to ultraviolet radiation].

Quantitative 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.

[The effect of long-term UV radiation exposure on the skin autonomous microflora and on body nonspecific resistance].

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.

[Natural ultraviolet radiation as a human risk factor (review)].

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.

[The biomedical effects of ultraviolet radiation and their mechanisms].

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.

[Spectral and energy parameters of the biological effect of UV-irradiation and approaches to its standardization].

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.

[The effect of prolonged exposure to UV radiation on the state of the ocular media and on the parameters of the electroretinogram in the rabbit].

Rabbits 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).

[Parameters of the optokinetic reaction in the rabbit following acute exposure of the eyes to UV-radiation].

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.

[Medico-biological effects of natural UV-radiation: global consequences of the destruction of the ozone layer].

The 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.

[The effect of singly-administered super-erythematous doses of UV-radiation on the general body resistance of hairless mice].

Male 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.

[Sensitivity of mammalian tissues to prolonged exposure to high-tension permanent magnetic fields].

The 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.

[Tissue specificity of changes in mitotic activity induced by strong magnetic fields].

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.

[Effect of strong, infralow-frequency magnetic fields on bone marrow cell division].

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.

Influence of infralow-frequency magnetic fields of high and ultrahigh intensity on the division of mammalian cells in vivo.

The 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.

[Proliferation of bone marrow cells upon exposure to constant magnetic fields of ultra-high strength].

A study was made of the 0.5--24 hour effects of the stable magnetic field (SMF), with 9.9--42.

[Effect on mitotic activity of prolonged exposure to constant and alternating 1000 oersted magnetic fields].

During 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.

[Physiologic regeneration of corneal epithelium following exposure to constant magnetic fields of super-high intensity].

The mitotic index of mouse corneal epithelium was studied during and after 0.5-- 24 hours exposures to 9.9-39.