Microbial release of 226Ra2+ from (Ba,Ra)SO4 sludges from uranium mine wastes

226Ra2+ is removed from uranium mine effluents by coprecipitation with BaSO4. (Ba,Ra)SO4 sludge samples from two Canadian mine sites were found to contain active heterotrophic populations of aerobic, anaerobic, denitrifying, and sulfate-reducing bacteria. Under laboratory conditions, sulfate reduction occurred in batch cultures when carbon sources such as acetate, glucose, glycollate, lactate, or pyruvate were added to samples of (Ba,Ra)SO4 sludge. No external sources of nitrogen or phosphate were required for this activity. Further studies with lactate supplementation showed that once the soluble SO4(2-) in the overlying water was depleted, Ba2+ and 226Ra2+ were dissolved from the (Ba,Ra)SO4 sludge, with the concurrent production of S2-. Levels of dissolved 226Ra2+ reached approximately 400 Bq/liter after 10 weeks of incubation. Results suggest that the ultimate disposal of these sludges must maintain conditions to minimize the activity of the indigenous sulfate-reducing bacteria to ensure that unacceptably high levels of 226Ra2+ are not released to the environment.     

Microbial release of 226Ra2+ from (Ba,Ra)SO4 sludges from uranium mine wastes.

226Ra2+ is removed from uranium mine effluents by coprecipitation with BaSO4. (Ba,Ra)SO4 sludge samples from two Canadian mine sites were found to contain active heterotrophic populations of aerobic, anaerobic, denitrifying, and sulfate-reducing bacteria. Under laboratory conditions, sulfate reduction occurred in batch cultures when carbon sources such as acetate, glucose, glycollate, lactate, or pyruvate were added to samples of (Ba,Ra)SO4 sludge. No external sources of nitrogen or phosphate were required for this activity. Further studies with lactate supplementation showed that once the soluble SO4(2-) in the overlying water was depleted, Ba2+ and 226Ra2+ were dissolved from the (Ba,Ra)SO4 sludge, with the concurrent production of S2-. Levels of dissolved 226Ra2+ reached approximately 400 Bq/liter after 10 weeks of incubation. Results suggest that the ultimate disposal of these sludges must maintain conditions to minimize the activity of the indigenous sulfate-reducing bacteria to ensure that unacceptably high levels of 226Ra2+ are not released to the environment.     

A comparison of the natural survival of beagle dogs injected intravenously with low levels of 239Pu, 226Ra, 228Ra, 228Th, or 90Sr

The natural survival, relative to properly chosen controls, of 26 beagle dogs injected once intravenously with an average of 0.58 +/- 0.04 kBq 239Pu/kg, 23 dogs injected with 2.31 +/- 0.43 kBq 226Ra/kg, 13 dogs injected with 1.84 +/- 0.26 kBq 228Ra/kg, 12 dogs injected with 0.56 +/- 0.030 kBq 228Th/kg, and 12 dogs injected with 21.13 +/- 1.74 kBq 90Sr/kg was evaluated statistically. The amounts of these radionuclides are related directly to the estimated maximum permissible body burdens for humans suggested in ICRP II (1959). They constitute a level of exposure that initially was assumed to cause no deleterious effects in dogs. This study had two objectives: (1) identification of homogeneous control groups against which to evaluate the survival of the irradiated groups and (2) comparison of the survival characteristics and estimation of mortality or hazard rate ratios for control dogs vs dogs injected with the baseline dosages given above. It was shown, by goodness-of-fit plots, that the Cox proportional hazards model was an appropriate method of analysis. Therefore, covariates that possibly could influence survival were tested for significance. Only the effects of grand mal seizure, which is caused in epileptic dogs by an external stimulus and can be fatal if untreated, were significant (P less than 0.0001). Consequently, in the final model, death from grand mal seizure was considered as accidental. After censoring the dogs dying from grand mal seizure, it was established that the data for the control groups from previous and contemporary experiments could be pooled. The change in hazard rates relative to controls resulting from exposure to the baseline radionuclide level was modest, 1.6 times for 239Pu (P = 0.033), 1.0(4) for 226Ra (P = 0.86), 1.9 for 228Ra (P = 0.035), 2.5 for 228Th (P less than 0.001), and 0.52 for 90Sr (P = 0.041). Bone tumor induction was clearly elevated in dogs injected with 239Pu and 228Th. When the effect of these bone tumors on survival was removed by censoring, the dogs injected with 239Pu were indistinguishable from the controls. In contrast, the effects of bone tumor on group survival of the 228Ra and 228Th dogs were not significant. Thus, no additional life-shortening effects beyond those attributable to bone tumor were suggested by these data for 239Pu, but other, as yet unspecified, confounders are suggested for 228Ra and 228Th.     

Solid-phase synthesis of ragweed allergen Ra5

A two-stage strategy was used to synthesize the 45-residue, four-disulfide-bonded ragweed protein allergen Ra5: (i) the protected linear chain was prepared by solid-phase, stepwise synthesis according to the sequence of the fully reduced protein; (ii) after removal from the resin and deprotection by hydrogen fluoride, the reduced chain was purified by gel filtration on Sephadex G-50 and allowed to fold “spontaneously” in the presence of oxidized dithiothreitol to form the disulfide links. The product (synthetic Ra5) was purified to disc-electrophoretic homogeneity by cycling through Sephadex G-50 and CM-Sephadex (overall yield: 6% theoretical). Synthetic Ra5 was closely similar in structure to the natural protein by amino acid analysis. polyacrylamide gel electrophoresis, tryptic peptide mapping, and circular dichroism spectra, as well asin vitro andin vivo immunoassays of antigenic/allergenic activities.     

Adenosine 3',5'-monophosphate in Mycobacterium phlei and Mycobacterium tuberculosis H37Ra.

Adenosine 3',5'-monophosphate (cAMP) is present in slow growing as well as fast growing mycobacteria. Apparently there does not seem to be any direct relationship between either intra- or extracellular cAMP content with the growth rate of bacilli. As compared to that of E. coli grown on a similar energy source, cAMP content is much higher in mycobacteria. cAMP content inside the cells remains unaltered throughout the growth period and this may be due to lack of complete utilization of the major energy source, glycerol. Glucose when added to the cells, suspended in phosphate buffer, caused a remarkable decrease in intracellular cAMP content, a phenomenon well established in other bacteria.     

Polymorphism of Crystals of Salmonella minnesota Re and Ra Lipopolysaccharides

Salmonella minnesota Re and Ra lipopolysaccharides (LPSs) formed three-dimensional crystals when they were precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl₂ and incubated in 70% ethanol containing 250 mM MgCl₂ at 4 C. Besides typical shapes of crystals, hexagonal plates and solid columns, which were already reported (J. Bacteriol. 172: 1516–1528 (1990)), the LPSs thus treated formed crystals possessing various shapes such as square or rectangular plate, lozenge plate, discoid, and truncated hexangular pyramid forms. Electron diffraction patterns from all these crystals except square or rectangular plate crystals obtained by electron irradiation from the direction perpendicular to the basal plane were essentially the same as those from hexagonal plate crystals, indicating that they consist of hexagonal lattices with the lattice constant of 4.62 Å. From these results as well as the results of electron microscopic observations of these crystals, it was concluded that all these crystals except square or rectangular plate crystals are composed of hexagonal plate sheets as the basic structural units. Square or rectangular crystals were assumed to correspond to the {1011} planes of solid hexagonal column crystals.     

The dosimetry of 224Ra in mouse bone

Calculations are described, based on experimental findings, which show the variation of absorbed dose from 224Ra in bone marrow of CBA/H mice. These calculations indicate that, following an injection of a leukaemogenic amount of 16 kBq 224Ra into these mice, most marrow cells in the cancellous bone of femur ends are killed but most marrow cells in the femur shaft survive. The calculations also suggest that the mean leukaemogenic absorbed dose of about 1.5 Gy is received by a population of marrow cells about 30 microns from bone surface in the femur shaft.     

Immunochemical and genetic studies of Amb.t. V (Ra5G), an Ra5 homologue from giant ragweed pollen

Giant ragweed pollen allergen Amb.t. V (Ra5G), a homologue of short ragweed pollen Amb.a. V (Ra5S), was isolated in ultrapure form from a 16-min extract of ragweed pollen by a combination of molecular sieving through an Amicon hollow fiber cartridge (H1P5), cation-exchange chromatography, and gel filtration. The size was found to be 4400 daltons (D) by amino acid analysis and 6000 D by SDS-PAGE, and the pI was 8.3 as determined by isoelectric focusing. There was no cross-reactivity detected between the two Amb. V antigens by immunodiffusion and IEP with the use of hyperimmune antisera raised against crude or highly purified antigens. Cross-reactivity between the two Amb. V antigens was further investigated by inhibition double antibody radioimmunoassay by using the sera of nine selected ragweed-allergic patients who had recently been immunized with either mixed short-giant ragweed pollen extract or with short ragweed extract alone and who had IgG antibodies (Ab) to Amb.t. V and generally to Amb.a. V. Unlabeled Amb.t. V did not inhibit the binding of 125I-Amb.a. V to the IgG Ab in any of the sera tested. Conversely, unlabeled Amb.a. V produced some inhibition of the binding of 125I-Amb.t. V to the patients' IgG Ab, primarily in those patients who had received immunotherapy with short ragweed alone. This weak cross-reactivity was probably a result of the primary structural homology between the two protein allergens. The sera from two groups of ragweed-allergic individuals were investigated for the presence of IgG and IgE Ab to Amb.t. V. The presence of IgG Ab was found to be associated both with previous (or current) immunotherapy with giant ragweed extract and with HLA-Dw2. The HLA association is of interest in view of the previously established association between Dw2 and response toward the homologue Amb.a. V. The result suggests the existence of a similar genetic control at the primary level of antigenic recognition of the two Amb. V antigens.     

Assessments of 226Ra and 222Rn concentration in well and tap water from Sik,Malaysia, and consequent dose estimates

Abstract

The ingestion of ²²⁶Ra, inhalation, and ingestion of ²²²Rn in water is considered the primary health risk for lungs and stomach. This study presents the concentrations of ²²⁶Ra and ²²²Rn in well and tap water collected from Sik, Malaysia, using HPGe and RAD7 detectors. Maximum average concentrations of ²²⁶Ra and ²²²Rn were found 47.6?±?3.6 mBq/l and 9.3?±?1.4?Bq/l in well water, respectively, and minimum were found 17.1?±?3.6 mBq/l and 1.6?±?1.0?Bq/l in tap water, respectively. A positive correlation (R=.88) was found between ²²⁶Ra and ²²²Rn determined by HPGe and RAD7 detectors, respectively. Infants in the age group of 0–1 y appeared to be at risk with respect to the annual effective doses from ²²⁶Ra and ²²²Rn as compared to the other age groups. However, annual effective doses for all three age groups from intake of ²²⁶Ra and ²²²Rn in well and tap drinking water were found below the World Health Organization (WHO) recommended level of .1 mSv/y_.     

Background concentration of 226Ra in terrestrial animals

Evidence that environmental levels of vanadium are increasing hasraised concern over the injection of vanadium into the environmentfrom anthropogenic sources. Two simple global mass balance models(simulating current and pre-industrial conditions) were developed todemonstrate the influence of anthropogenic vanadium on the globaldistribution of this trace metal. Current vanadium emissions owing toman's current industrial activities were estimated to comprise 30% oftotal atmosphere loading, 3% of total ocean loading, and 6% of totalland loading. These loadings were always considerably less than thoseresulting from non-anthropogenic sources or events. Differences notedbetween the pre-industrial and current models were not sufficientlygreat to suggest that injection of anthropogenic vanadium constitutes asignificant environmental threat on a global scale.     

The balance between IL-1 and IL-1Ra in disease

IL-1 is an important mediator of inflammation and tissue damage in multiple organs, both in experimental animal models of disease and in human diseases. The IL-1 family consists of two agonists, IL-1alpha and IL-1beta, two receptors, biologically active IL-1RI and inert IL-1RII, and a specific receptor antagonist, IL-1Ra. The balance between IL-1 and IL-1Ra in local tissues plays an important role in the susceptibility to and severity of many diseases. An allelic polymorphism in the IL-1Ra gene has been associated with a variety of human diseases primarily of epithelial and endothelial cell origin. This association may be secondary to an imbalance in the IL-1 system with enhanced production of IL-1beta and reduced production of the major intracellular isoform of IL-1Ra. Treatment of RA with daily subcutaneous injections of recombinant IL-1Ra protein has been shown to be efficacious. Gene therapy approaches with IL-1Ra are being evaluated for the treatment of RA and other human diseases.     

Analysis of HLA DR, HLA DQ, C4A, FcgammaRIIa, FcgammaRIIIa, MBL, and IL-1Ra allelic variants in Caucasian systemic lupus erythematosus patients suggests an effect of the combined FcgammaRIIa R/R and IL-1Ra 2/2 genotypes on disease susceptibility

Dysfunction in various parts of immune defence, such as immune response, immune complex clearance, and inflammation, has an impact on pathogenesis in systemic lupus erythematosus (SLE). We hypothesised that combinations of common variants of genes involved in these immune functions are associated with susceptibility to SLE. The following variants were analysed: HLA DR3, HLA DQ2, C4AQ0, Fcγ receptor IIa (FcγRIIa) genotype R/R, Fcγ receptor IIIa (FcRγIIIa) genotype F/F, mannan-binding lectin (MBL) genotype conferring a low serum concentration of MBL (MBL-low), and interleukin-1 receptor antagonist (IL-1Ra) genotype 2/2. Polymorphisms were analysed in 143 Caucasian patients with SLE and 200 healthy controls. HLA DR3 in SLE patients was in 90% part of the haplotype HLA DR3-DQ2-C4AQ0, which was strongly associated with SLE (odds ratio [OR] 2.8, 95% CI 1.7–4.5). Analysis of combinations of gene variants revealed that the strong association with SLE for HLA DR3-DQ2-C4AQ0 remained after combination with FcγRIIa R/R, FcγRIIIa F/F, and MBL-low (OR>2). Furthermore, the combination of the FcγRIIa R/R and IL-1Ra 2/2 genotypes yielded a strong correlation with SLE (OR 11.8, 95% CI 1.5–95.4). This study demonstrates that certain combinations of gene variants may increase susceptibility to SLE, suggesting this approach for future studies. It also confirms earlier findings regarding the HLA DR3-DQ2-C4AQ0 haplotype.     

Using the RESRAD Code to Assess Human Exposure Risk to 226Ra, 232Th,and 40K in Soil

This article evaluates the health risk raised by exposure to naturally occurring radionuclides in soil around Khak-Sefid, Ramsar, Iran, which is an area of high natural background radiation. A high purity germanium detector was used to determine levels of radionuclides in soil samples and the cancer morbidity risk for a hypothetical resident farmer was evaluated using the RESidual RADioactivity (RESRAD) code. The average activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 13,201 ± 391, 27.9 ± 2.4, and 415.5 ± 16 Bq/kg, respectively. The maximum assessed cancer morbidity risks were calculated from external and internal exposure pathways as 4.73 × 10^?2 and 3.40 × 10^?2 for ²²⁶Ra, 1.41 × 10^?4 and 7.88 × 10^?5 for ²³²Th, and 1.3 × 10^?4 and 4.233 × 10^?4 for ⁴⁰K. The RESRAD calculations also showed total cancer morbidity risks from external gamma and plant ingestion pathways were more important than from other exposure pathways. A sensitivity analysis was also performed to determine the input parameter values in the risk assessment process. In general, due to the high calculated risk of ²²⁶Ra compared with ²³²Th and ⁴⁰K it can be the major source of concern for human heath in the study area.