Destruction and regeneration of the seminiferous tubules after local x-ray irradiation of the testes of sexually mature rats

It was established that the local X-irradiation (1000 R) of testes of the adult rats results a total destruction of seminiferous tubules. The restitution of the organ structure proceeds via formation of new seminiferous tubules in which spermatogenic epithelium later develops. Rete testis and germ cells preserved in its epithelium from embryogenesis are a source of regeneration material. The results obtained favour the suggestion about the dynamic structure of mammalian testis.     

Life-span of rats as affected by a combination of external (137Cs) and internal (237Np) radiation

A study was made of a change in the mean life of rats exposed to external gamma-radiation (51.6 mC/kg) and 237Np (a polymeric nitrate form) administered intratracheally (0.2-188.0 kBq/kg) delivered separately and in a combination. It was established that the effects of gamma- and alpha-radiation were summated.     

Isoform-dependent effects of apoE on doublecortin-positive cells and microtubule-associated protein 2 immunoreactivity following 137Cs irradiation

Previously we found apoE isoform-dependent effects of ¹³⁷Cs irradiation on cognitive function of female mice 3 months following irradiation. Alterations in the number of immature neurons and in the levels of the dendritic marker microtubule-associated protein 2 (MAP-2) might contribute to the cognitive changes following irradiation. Therefore, in the present study we determined if, following ¹³⁷Cs irradiation, there are apoE isoform-dependent effects on loss of doublecortin-positive neuroprogenitor cells or MAP-2 immumonoreactivity. In the dentate gyrus, CA1 and CA3 regions of the hippocampus, enthorhinal and sensorimotor cortex, and central and basolateral nuclei of the amygdala of apoE3 female mice, MAP-2 immunoreactivity increased 3 months following ¹³⁷Cs irradiation. In addition, at 8 h following irradiation, the number of doublecortin-positive cells was higher in apoE3 than apoE2 or apoE4 mice. Together, these data indicate that brains of apoE3 mice respond differently to ¹³⁷Cs irradiation than those of apoE2 or apoE4 mice.     

Comparative effects of X irradiation on the testes of adult Sprague-Dawley and Wistar rats

The response of the testes of two strains of adult rats (Sprague-Dawley and Wistar) to graded single doses and split doses of 230 kVp X rays has been investigated. A marked difference was noted between the strains in the response of the clonogenic spermatogonia to irradiation, as measured histologically by the repopulation index. Single-dose response curves derived for these cells in the Sprague-Dawley strain had a much larger shoulder (up to about 4-5 Gy) than for the Wistar (less than 2 Gy). Split-dose studies revealed that this difference may partly be explained by a greater repair capacity in the cells of the Sprague-Dawley strain. Changes in serum FSH concentrations mirrored the changes in clonogenic spermatogonial survival following split doses of radiation.     

137Cs distribution and accumulation in the tissues of cultivated fungi (Pleurotus ostreatus)

The authors examined 137Cs accumulation and distribution in different structures and tissues of Pleurotus ostreatus cultivated under laboratory conditions. The fungi were shown to concentrate 137Cs. A higher concentrations of the radionuclides in the fungi compared to their substrate is manifested at the first stages of the fruit body formation, the maximum content of 137Cs is accumulated by fungi in the middle of bearing stage. The fungus tissues are different by their accumulative capacity as follows (ascending range): central, more dense part of the stipe < stipe < mycelium < cap < generative tissues. 137Cs accumulation in the fruit bodies depends also on the fungus size and age.     

Comparison of Prussian blue and apple-pectin efficacy on 137Cs decorporation in rats

Cesium-137 (137Cs) is one of the most important nuclear fission elements that contaminated the environment after the explosion of the Chernobyl nuclear power plant in Ukraine (1986). The aim of the study was to compare the efficacy of two chelating agent, Prussian blue and apple-pectin on 137cesium decorporation in rats. Rats were intravenously injected with a solution of 137cesium (5 kBq per rat). Chelating agents, Prussian blue or apple-pectin were given immediately after Cs contamination and during 11 days by addition of each chelating agent in drinking water at a concentration corresponding to 400 mg kg(-1) day(-1). Efficiency was evaluated 11 days after contamination (at the end of treatment) through their ability to promote Cs excretion and to reduce the radionuclide accumulation in some retention compartments (blood, liver, kidneys, spleen, skeleton and in the remaining carcass). In these conditions after treatment with Prussian blue a fivefold increase in fecal excretion of Cs was observed and was associated with a reduction in the radionuclide retention in the main organs measured. In contrast, no significant differences were observed between untreated rats and rats treated with apple-pectin. These observations were discussed in terms of ability of pectins to bind Cs and compared to recently published results obtained after treatment of Cs-contaminated children with this chelate.     

Pathomorphological picture of the testes of mice administered antitumor antibiotics and their comparative evaluation

A single administration of the LD50 of bruneomycin, carminomycin, rubomycin or olivomycin and the use of the antibiotics for 10 days in a dose 2 times higher than the therapeutic one and amounting to 10 per cent of the LD50 induced dystrophic and destructive changes in the sexual glands of mice. The changes in the testis were more pronounced after the single use of the antibiotics. Recovery processes were observed in the testis beginning from the middle of the third week after the use of carminomycin and rubomycin and from the end of the second week after the use of olivomycin. Bruneomycin was an exception: the pronounced destructive changes in the sexual glands after its single or repeated use persisted within the observation period.     

A comparative evaluation of the clinical x-ray picture of uremic osteodystrophy before and after parathyroidectomy]

The authors present the results of clinical, x-ray, and biochemical studies carried out in 51 patients with uremic osteodystrophy, treated with hemodialysis, before and after parathyroidectomy. The patients were divided into 4 groups with various patterns of x-ray symptoms. Patients with x-ray signs of fibrous osteodystrophy made up group 1, the second group consisted of patients with a combination of fibrous osteodystrophy and osteomalacia with secondary hyperparathyrosis predominance; the third group, like the second one, included patients with the mixed form of uremic osteodystrophy, but with the predominance of the osteomalacic syndrome; Group 4 patients had no x-ray signs of bone changes, and the diagnosis of uremic osteodystrophy was confirmed by clinical laboratory evidence. Analysis of the clinical and x-ray data before and after parathyroidectomy has brought the authors to a conclusion that such an intervention was effective only in cases with manifest clinical and x-ray symptoms of fibrous osteodystrophy. In Group 2 patients with the mixed form of uremic osteodystrophy and less manifest osteomalacia as against fibrous osteodystrophy, subtotal or partial parathyroidectomy is advisable only in cases when conservative therapy is of no avail and fibrous dystrophy is progressing. Surgical treatment is contraindicated to patients in whom x-ray signs of osteomalacia predominate over fibrous osteodystrophy in the total picture of uremic osteodystrophy; it may result in a rapid progress of osteomalacia.     

Diverse delayed effects in human lymphoblastoid cells surviving exposure to high-LET (56)Fe particles or low-LET (137)Cs gamma radiation

To obtain information on the origin of radiation-induced genomic instability, we characterized a total of 166 clones that survived exposure to (56)Fe particles or (137)Cs gamma radiation, isolated approximately 36 generations after exposure, along with their respective control clones. Cytogenetic aberrations, growth alterations, responses to a second irradiation, and mutant frequencies at the Na(+)/K(+) ATPase and thymidine kinase loci were determined. A greater percentage of clones that survived exposure to (56)Fe particles exhibited instability (defined as clones showing one or more outlying characteristics) than in the case of those that survived gamma irradiation. The phenotypes of the unstable clones that survived exposure to (56)Fe particles were also qualitatively different from those of the clones that survived gamma irradiation. A greater percentage (20%) of the unstable clones that survived gamma irradiation than those that survived exposure to (56)Fe particles (4%) showed an altered response to the second irradiation, while an increase in the percentage of clones that had an outlying frequency of ouabain-resistant and thymidine kinase mutants was more evident in the clones exposed to (56)Fe particles than in those exposed to gamma rays. Growth alterations and increases in dicentric chromosomes were found only in clones with more than one alteration. These results underscore the complex nature of genomic instability and the likelihood that radiation-induced genomic instability arises from different original events.     

Long-term effects of combined exposure to external 137Cs gamma-radiation and incorporated 239Pu

A study was made of the delayed effects of mixed exposure to 137Cs-gamma-radiation (a single exposure) and 239Pu (a single intravenous injection) in doses approximating optimal blastomogenic ones. The results are calculated per 1 cGy of weighted mean dose within the body with regard for RBE (1 cSv), per cent of osteosarcomas (per 1 cGy in endosteum and periosteum). A conclusion is made of a complete summation of main biological effects per 1 cSv of the dose absorbed.     

Cytogenetic effects of combined radioactive (137Cs) and chemical (Cd, Pb, and 2,4-D herbicide) contamination on spring barley intercalar meristem cells

The frequency of cytogenetic effects in spring barley intercalar meristem cells was studied in the presence of a range of different stressors. There was a non-linear dependence on the concentrations of 137Cs, Cd, Pb, and dichlorophenoxyacetic acid (2,4-D) herbicide contamination in the exposure ranges used. The frequency of cytogenetic effects increased at the lower concentrations of the pollutants more rapidly than at the higher concentrations. Contamination of the soil by lead at a concentration that meets the current standards for permissible content in soil, and by 2,4-D herbicide at the application levels recommended for agricultural use resulted in a significant increase in aberrant cell frequency. In these cases, the extent of the observed cytogenetic effects was comparable with the effect induced by a 137Cs soil contamination of 49.2 kBq/kg, a level that exceeds by 10-fold the maximum level permitted in radionuclide-contaminated areas where people are resident. In most cases, the experimentally observed combined effects of the pollutants studied differed from those expected from an additive hypothesis. When combined with 137Cs contamination, antagonistic effects became increasingly stronger when the second stressor was changed from cadmium to lead, and then to the herbicide, as measured both by tests of the 'frequency of aberrant cells' and the 'aberrations per cell'. Data from this study and previous reported literature suggest that synergistic increases in cytogenetic effects can be induced by the simultaneous influence of several stressors even at low intensities. This indicates that there is a capability for mutual intensification of the effects of environmental factors that actually occur in situations of low-level exposure.     

Monovalent-ion carrier effects on transport of Rb86 and Cs137 into bush bean plants

Summary Bush bean plants were exposed to either Rb⁸⁶ or Cs¹³⁷ for 24 hours with different monovalent cations as carriers in single-salt solutions except for the presence of 10⁻⁴ M CaCl₂. Ratio of uptake of the radionuclides at 10⁻³ to 10⁻² M was used as an index of the carrier ability of various cations. Different monovalent cations decreased uptake of Cs¹³⁷ and its transport to shoots unequally when 10⁻² M salts were compared with 10⁻³ M salts. Rubidium and cesium salts decreased Cs¹³⁷ uptake equally but potassium salts were less effective in decreasing uptake when the ratios of the two concentrations were considered. All monovalent cations decreased uptake of Cs¹³⁷ at the 10⁻² M carrier concentration but some did not at 10⁻³ M. Nitrate nitrogen was a big factor in these results. Cesium and rubidium salts were most effective. Potassium appeared to increase Cs¹³⁷ transport to shoots particularly at 10⁻³ M KNO₃. Only cesium, rubidium, and potassium salts decreased uptake of Rb⁸⁶ when 10⁻² M salts were compared with 10⁻³ M. Rubidium and cesium salts decreased uptake essentially equally and potassium salts again were less effective. All nitrate salts tended to increase Rb⁸⁶ transport to shoots more consistently than with Cs¹³⁷. It is concluded that absorption and transport to shoots were not equivalent for potassium, rubidium, and cesium.