BeSO4 Research Articles

Carcinogenic potential and genomic instability of beryllium sulphate in BALB/c-3T3 cells.

Occupational exposure to beryllium (Be) and Be compounds occurs in a wide range of industrial processes. A large number of workers are potentially exposed to this metal during manufacturing and processing, so there is a concern regarding the potential carcinogenic hazard of Be. Studies were performed to determine the carcinogenic potential of beryllium sulfate (BeSO4) in cultured mammalian cells. BALB/c-3T3 cells were treated with varying concentrations of BeSO4 for 72 h and the transformation frequency was determined after 4 weeks of culturing. Concentrations from 50-200 microg BeSO4/ml, caused a concentration-dependent increase (9-41 fold) in transformation frequency. Non-transformed BALB/c-3T3 cells and cells from transformed foci induced by BeSO4 were injected into both axillary regions of nude mice. All ten Be-induced transformed cell lines injected into nude mice produced fibrosarcomas within 50 days after cell injection. No tumors were found in nude mice receiving non-transformed BALB/c-3T3 cells 90 days post-injection. Gene amplification was investigated in K-ras, c-myc, c-fos, c-jun, c-sis, erb-B2 and p53 using differential PCR while random amplified polymorphic DNA fingerprinting was employed to detect genomic instability. Gene amplification was found in K-ras and c-jun, however no change in gene expression or protein level was observed in any of the genes by Western blotting. Five of the 10 transformed cell lines showed genetic instability using different random primers. In conclusion, these results indicate that BeSO4 is capable of inducing morphological cell transformation in mammalian cells and that transformed cells induced by BeSO4 are potentially tumorigenic. Also, cell transformation induced by BeSO4 may be attributed, in part, to the gene amplification of K-ras and c-jun and some BeSO4-induced transformed cells possess neoplastic potential resulting from genomic instability.

Beryllium, an adjuvant that promotes gamma interferon production.

Beryllium is associated with a human pulmonary granulomatosis characterized by an accumulation of CD4(+) T cells in the lungs and a heightened specific lymphocyte proliferative response to beryllium (Be) with gamma interferon (IFN-gamma) release (i.e., a T helper 1 [Th1] response). While an animal model of Be sensitization is not currently available, Be has exhibited adjuvant effects in animals. The effects of Be on BALB/c mice immunized with soluble leishmanial antigens (SLA) were investigated to determine if Be had adjuvant activity for IFN-gamma production, an indicator of the Th1 response. In this strain of Leishmania-susceptible BALB/c mice, a Th2 response is normally observed after in vivo SLA sensitization and in vitro restimulation with SLA. If interleukin-12 (IL-12) is given during in vivo sensitization with SLA, markedly increased IFN-gamma production and decreased IL-4 production are detected. We show here that when beryllium sulfate (BeSO(4)) was added during in vivo sensitization of BALB/c mice with SLA and IL-12, significantly increased IFN-gamma production and decreased IL-4 production from lymph node and spleen cells were detected upon in vitro SLA restimulation. No specific responses were observed to Be alone. Lymph node and spleen cells from all mice proliferated strongly and comparably upon in vitro restimulation with SLA and with SLA plus Be; no differences were noted among groups of mice that received different immunization regimens. In vivo, when Be was added to SLA and IL-12 for sensitization of BALB/c mice, more effective control of Leishmania infection was achieved. This finding has implications for understanding not only the development of granulomatous reactions but also the potential for developing Be as a vaccine adjuvant.

Complexation of Beryllium(II) by Maleic and Succinic Acid

Abstract Beryllium succinate dihydrate [Be(C4H4O4)](H2O)2 is formed in the reaction of equimolar quantities of beryllium sulfate, succinic acid and barium hydroxide in aqueous solution at pH 3.2. Sodium, potassium, and ammonium bis(succinato)beryllates M2[Be(C4H4O4)2] are obtained using the same reagents in the molar ratio 1:2:1 and adjusting the pH to 6.3-6.5 with NaOH, KOH or concentrated aqueous ammonia, respectively. The corresponding potassium bis(maleato)beryllate is prepared similarly and obtained as a crystalline monohydrate, the structure of which has been determined by X-ray methods. The lattice contains spiro-bicyclic dianions with the Be atom chelated by two dicarboxylate ligands. The compounds undergo slow hydrolysis in water as shown by time-and pH-dependent 9Be NMR spectroscopy. In the neutral region (pH 6.5-6.9) the maleinato complexes are in an equilibrium with trinuclear compounds M3{[Be(C4H2O4)OH]3} as the predominating species, while in acid solution (at pH 1.3) only the aquo complex [Be(H2O4]2+ remains. In the intermediate pH region various complexes of the above types coexist, with only very slow ligand exchange (on the NMR time scale).

Expansions of T-cell subsets expressing particular T-cell receptor variable regions in chronic beryllium disease.

Chronic beryllium disease (CBD) is a granulomatous disorder characterized by the presence of noncaseating granulomas and mononuclear cell inflammation, occurring in 1 to 5% of people exposed to beryllium in the workplace. In the lungs of affected patients, CD4(+) T cells accumulate. Using anti-T-cell receptor (TCR) monoclonal antibodies, we investigated the TCR beta and alpha variable (Vbeta and Valpha, respectively) repertoire in the bronchoalveolar lavage (BAL) and blood of both CBD patients and healthy controls. There was marked heterogeneity within the BAL CD4(+) T-cell repertoire in both patients and controls. However, 11 of the 28 CBD patients demonstrated 16 different T-cell subset expansions within the BAL as compared with only one expansion in ten healthy controls. Five of the 16 expansions in CBD patients expressed Vbeta3. Altered TCR expression within the BAL T-cell repertoire appeared to persist over time in patients who underwent repeat evaluation. After in vitro stimulation of BAL T cells with beryllium sulfate and interleukin-2, we noted further alteration of the BAL TCR repertoire in some individuals. These results provide additional insight into the involvement of CD4(+) T cells in this disease and form the basis for studies to examine the nature of the stimulating antigen.

Ação promotora do berílio em catalisadores da síntese do estireno

The catalytic dehydrogenation of ethylbenzene in presence of steam is the main commercial route to produce styrene. The industrial catalysts are potassium- and chromia-doped hematite which show low surface areas leading to bad performance and short life. In order to develop catalysts with high areas, the effect of beryllium on the textural properties and on the catalytic performance of this iron oxide was studied. The influence of the amount of the dopant, the starting material and the calcination temperature were also studied. In sample preparations, iron and beryllium salts (nitrate or sulfate) were hydrolyzed with ammonia and then calcinated. The experiments followed a factorial design with two variables in two levels (Fe/Be= 3 and 7; calcination temperature= 500 and 700oC). Solids without any dopant were also prepared. Samples were characterized by elemental analysis, infrared spectroscopy, surface area and porosity measurements, X-ray diffraction, DSC and TG. The catalysts were tested in a microreactor at 524oC and 1 atm, by using a mole ratio of steam/ ethylbenzene=10. The selectivity was measured by monitoring styrene, benzene and toluene formation. It was found that the effect of beryllium on the characteristics of hematite and on its catalytic performance depends on the starting material and on the amount of dopant. Surface areas increased due to the dopant as well as the nature of the precursor; samples produced by beryllium sulfate showed higher areas. Beryllium-doped solids showed a higher catalytic activity when compared to pure hematite, but no significant influence of the anion of starting material was noted. It can be concluded that beryllium acts as both textural and structural promoter. Samples with Fe/Be= 3, heated at 500oC, lead to the highest conversion and were the most selective. However, catalysts prepared from beryllium sulfate are the most promising to ethylbenzene dehydrogenation due to their high surface area which could lead to a longer life.

Gadolinium chloride reduces cytochrome P450: Relevance to chemical-induced hepatotoxicity

The Kupffer cell inhibitor, gadolinium chloride (GdCl3), protects the liver from a number of toxicants that require biotransformation to elicit toxicity (i.e. 1,2-dichlorobenzene and CCl4), as well as compounds that do not (i.e. cadmium chloride and beryllium sulfate). The mechanism of this protection is thought to result from reduced secretion of inflammatory and cytotoxic products from Kupffer cells (KC). However, since other lanthanides have been shown to decrease cytochrome P450 (P450) activity, the following studies were designed to determine if GdCl3 pretreatment alters hepatic P450 levels or activity. The toxicological relevance of GdCl3-mediated alterations in P450 activity was also estimated by determining the effect of GdCl3 pretreatment on the susceptibility of primary cultured hepatocytes to CCl4 and cadmium chloride (CdCl2). Male and female Sprague-Dawley rats were given GdCl3 (i.v., 10 mg/kg). Twenty-four hours later, livers were either processed for preparation of microsomes or for primary cultures of hepatocytes. Gadolinium chloride treatment reduced total hepatic microsomal P450 as well as aniline hydroxylase activity by approximately 30% in males and 20% in females. In hepatocytes isolated from rats pretreated with GdCl3, the toxicity caused by CCl4, but not CdCl2 was reduced. Interestingly, when GdCl3 was administered in vitro to microsomes, there was no effect on either the microsomal P450 difference spectra or p-hydroxylation of aniline. However, when GdCl3 was incubated with isolated hepatocytes, the cytotoxicity of CCl4 (but not CdCl2) was partially attenuated. These results suggest that, in addition to its inhibitory effects on KC, GdCl3 produces other effects which may alter the susceptibility of hepatocytes to toxicity caused by certain chemicals.

Beryllium induces IL-2 and IFN-gamma in berylliosis.

Chronic beryllium disease (CBD) provides a model for study of the Ag-stimulated, cell-mediated immune response that, over time, progresses to granulomatous lung disease. Using cells obtained with bronchoalveolar lavage from patients with CBD and normal individuals, we evaluated beryllium salt-stimulated T lymphocyte proliferation and production of proinflammatory cytokines. Our findings demonstrate that beryllium sulfate stimulates production of both IL-2 and IFN-gamma, not IL-4 and IL-7. We observed a brief time course for IL-2 protein (6-48 h after BeSO4 stimulation) and mRNA production (3-6 h) and a protracted time course for IFN-gamma protein (24-168 h) and mRNA (0.25-168 h). Beryllium-stimulated T lymphocyte proliferation and IFN-gamma release were only partially inhibited by neutralization of IL-2. On the basis of these findings, we hypothesized that IFN-gamma and the IL-2/IFN-gamma-inducible alpha subunit of the soluble IL-2 receptor were elevated in serum and bronchoalveolar lavage fluid of individuals with disease and were molecular markers of granulomatous disease. The data demonstrate that levels of the alpha subunit of the soluble IL-2 receptor, but not IFN-gamma, are elevated in the serum (median = 1428 U/ml; interquartile range = 823-2137 U/ml) and bronchoalveolar lavage fluid (median = 1.56 U/ml, interquartile range = 1.04-4.22 U/ml) of patients with CBD and correlate with the degree of pulmonary lymphocytosis and clinical measures of disease severity. We conclude that IL-2 and IFN-gamma are produced in the beryllium-stimulated, cell-mediated immune response with different time courses and that the alpha subunit of the soluble IL-2 receptor may serve as a biomarker of disease progression.

Beryllium Stimulates Release of T Helper 1 Cytokines Interleukin-2 and Interferon Gamma From BAL Cells in Chronic Beryllium Disease

Chronic beryllium disease (CBD) is an occupationally acquired lung disease that begins as a sensitizing cell-mediated immune response to beryllium antigen that, over time, results in the development of noncaseating granulomas. Previous studies demonstrated that this antigen-driven process involves the proliferation of CD4+ T lymphocytes. We hypothesize that disease results from changes in T helper 1 (Thl) cytokine release, leading to unopposed amplification of the inflammatory response by effector macrophages and Thl lymphocytes. To test this hypothesis, BAL cells from beryllium-diseased patients (n=5) and a nonexposed normal population (n=4) were cultured in the presence or absence of 10 pM beryllium sulfate and in the presence or absence of interleukin (IL)-2 neutralizing antibody for specified intervals up to 7 days. Protein concentrations of the Thl cytokines IL-2 and gamma interferon (IFN-γ) and for the Th2 cytokine IL-4 were measured by enzyme-linked immunosorbent assay (ELISA), and corresponding mRNA levels were determined by semiquantitative polymerase chain reaction (PCR). T lymphocyte proliferation was measured by tritiated thymidine incorporation.

Diffusion with hydrolysis and ion association in aqueous solutions of beryllium sulfate

Taylor dispersion is used to measure mutual diffusion coefficients for aqueous solutions of beryllium sulfate at concentrations from 0.005 to 1 mol-L−1 at 25°C. Least-squares analysis of the dispersion profiles shows that diffusion of the partially hydrolyzed salt produces a small additional flow of sulfuric acid, about 0.04 mol sulfuric acid per mole of total beryllium sulfate. Ternary diffusion coefficients measured for the aqueous BeSO4−H2SO4 system are qualitatively consistent with Nernst-Planck predictions based on the formation of beryllium sulfate ion pairs, bisulfate ions, and the hydrolysis equilibria 2Be2++H2O= Be2OH3++H+, 3Be2++2H2O=Be3(OH) 2 4+ +2H+. Except for very dilute solutions, the predicted flow of sulfuric acid is small compared to the flow of beryllium sulfate because most of the beryllium ions are protected from hydrolysis by the formation of BeSO4 ion pairs, and most of the hydrogen ions produced by hydrolysis are converted to less-mobile bisulfate ions.

Patch testing with beryllium alloy samples in guinea pigs.

An experimental study was conducted in guinea pigs for the predictive assessment of the beryllium alloy hazard in occupational exposure of the skin to beryllium compounds. Guinea pigs were sensitized to beryllium sulfate according to the maximized Magnusson and Kligman test, and challenged with beryllium alloys and metallic copper, beryllium and aluminum samples. Results showed a delayed skin hypersensitivity reaction in 30 to 60% of pre-sensitized guinea pigs challenged with copper-beryllium alloys and aluminum-beryllium alloy. An inflammatory follicular reaction was induced by copper in both controls and pre-sensitized guinea pigs.

The synergetic effect in beryllium sulfate tetrahydrate – an experimental electron-density study

The electron density in piezoelectric beryllium sulfate tetrahydrate has been determined by multipole refinement of single-crystal X-ray data collected at 30 K. Hydrogen positional and displacement parameters have been taken from a refinement using single-crystal neutron data. Structural parameters are also given based on single-crystal neutron data collected at 100 and 295 K. The Be 2+ ion causes a strong polarization of the lone-pair density of the water O atom. Only a single maximum of the deformation density is observed in this region

Beryllium-induced disturbances of the murine immune system reflect some phenomena observed in sarcoidosis.

Sarcoidosis is a systemic granulomatous disorder of unknown origin. In respect to clinical and immunological characteristics, it is indistinguishable from berylliosis. As an approach to develop a murine model reflecting some aspects of sarcoidosis, we attempted to induce berylliosis in mice by treating inbred F1 mice (C57B16 x DBA/2) with 3 mg beryllium sulfate (BeSO4) per kg body weight intraperitoneally. Either pure BeSO4 or BeSO4 in combination with incomplete Freund's adjuvant was administered. Alternatively, pure BeSO4 was injected 2 days after a single application of cyclophosphamide (150 mg/kg). The spleen index, the spontaneous and phorbolmyristate acetate (PMA)-induced radical oxygen intermediates (ROI) released by peritoneal macrophages, and the proliferative activity of spleen mononuclear cells in response to BeSO4 and concanavalin A (ConA) were evaluated and compared to the corresponding changes observed in sarcoidosis. In all three modes of BeSO4 treatment, the spontaneous ROI release by peritoneal macrophages was significantly elevated. These elevations were very similar to those observed with alveolar macrophages in active sarcoid alveolitis. After BeSO4 treatment, a small proliferative activity of spleen mononuclear cells in response to BeSO4 could be observed. Further, BeSO4-treated spleen mononuclear cells exhibited a markedly reduced response to ConA stimulation (approximately 20% of control) which parallels the reduced proliferative capacity of sarcoid peripheral blood mononuclear cells (approximately 45% of control). This reduction could be abolished by pretreating the mice with cyclophosphamide. BeSO4 treatment in combination with incomplete Freund's adjuvant resulted in a significant increase of spleen mononuclear cell proliferation (1.9-fold) after in vitro stimulation with BeSO4, and prevented the low responsiveness to ConA.(ABSTRACT TRUNCATED AT 250 WORDS)

Contact dermatitis from beryllium in dental alloys

An increasing number of metals with the potential to cause allergic contact dermatitis have found their way into dental alloys for economic and practical reasons. 2 patients are reported who developed gingivitis adjacent to the Rexillium III alloy in their dental prostheses. Patch testing demonstrated positive reactions to beryllium sulfate, a component of the alloy. Components of dental alloys and the mechanism of the contact dermatitis are discussed.

The micronucleus assay of beryllium sulfate tetrahydrate with mouse bone marrow and peripheral blood reticulocytes

The micronucleus assay of beryllium sulfate tetrahydrate with mouse bone marrow and peripheral blood reticulocytes

The inhibition of ATP-dependent shape change of human erythrocyte ghosts correlates with an inhibition of Mg(2+)-ATPase activity by fluoride and aluminofluoride complexes.

The vanadate-sensitive Mg(2+)-dependent ATPase activity of the human erythrocyte ghost is believed to be involved in the shape change events that convert echinocytic ghosts to smoothed forms (biconcave discs and stomatocytes). At physiological salt concentration, pH 7.4, 2 mM ATP, 5 mM Mg2+ and 1 mM EGTA, the Mg(2+)-ATPase activity of ghosts was inhibited strongly by millimolar concentrations of sodium fluoride: I50 = 1.31 +/- 0.23 mM (mean +/- S.D.; n = 12). The addition of aluminium chloride to 15 microM reduced the concentration of NaF required for 50% inhibition to 0.76 +/- 0.21 mM (n = 10). Aluminium alone had only a small inhibitory effect on the ATPase activity (13 +/- 9%; n = 10). Desferrioxamine, a strong chelator of tervalent aluminium ion, failed to reverse the inhibition by fluoride and reversed the inhibition in the presence of aluminium and fluoride back to those values obtained with fluoride alone. Of several metal salts tested only beryllium sulfate was able to replace aluminium as an effective inhibitor in the presence of fluoride. Inhibition of the Mg(2+)-ATPase activity by fluoride and the aluminofluoride complexes correlated with an inhibition of the rate of MgATP-dependent change in red cell ghost shape from echinocytes to smoothed forms. All gross morphological changes of the smoothing process were affected, including the production of discocytes, stomatocytes and endocyctic vesicles.

Subcellular localization of ziconium in nodular lymphatic cells after administration of soluble salts. Study by electron microprobe

In the literature two elements, beryllium and zirconium, have been described as inducing identical tissular lesions consisting of granulomas, which some authors have related to an immunological process. Intracellular lesions induced by beryllium sulphate have been studied previously [12]. These lesions were essentially characterized by intranuclear inclusions rich in beryllium. In this work we have studied intracellular concentration sites of zirconium after injection of low doses of zirconium sulphate. Results show that the intracellular concentration sites are very different between both elements, as zirconium is uniquely localized in the lysosomes of the lymph node macrophages where it is associated with phosphorus.

Studies on the genotoxicity of beryllium sulphate in vitro and in vivo

There is limited evidence that beryllium is a lung carcinogen to man, and several compounds of beryllium are carcinogenic to the lungs of the rat, rabbit and monkey. One such compound is beryllium sulphate (BeSO 4 · 4H 2O). This soluble salt has been evaluated in a range of genotoxicity tests. It was non-mutagenic to Salmonella typhimurium (strains TA1535, 1537, 1538, 98 and 100) when evaluated in the plate-incorporation assay at dose levels up to 5 mg/plate (± induced rat-liver S9 mix). It was also non-clastogenic to Chinese hamster lung (CHL) cells cultured in vitro. When dosed to male CBA mice via oral gavage at dose levels of 80% and 50% of the medium lethal dose (2.3 and 1.4 g/kg, respectively) it failed to increase the incidence of micronucleated polychromatic erythrocytes in the bone marrow (sampled at 24, 48 and 72 h post-dosing). However, a marked depression of erythropoiesis was evident 24 h after dosing suggestive of beryllium-mediated bone-marrow toxicity. When tested in the strain A mouse lung tumour bioassay, BeSO 4 induced a significant increase in the number of tumour-bearing animals but not in the number of lung tumours per animal. These findings are discussed within the contexts of other genotoxicity data published for BeSO 4, and of current strategies for the detection of possible human carcinogens.

Pathologic and immunologic alterations in early stages of beryllium disease. Re-examination of disease definition and natural history.

Beryllium lung disease is a chronic granulomatous disorder in which a beryllium-specific immune response plays a central role. By using a measure of cellular immune response to beryllium salts, bronchoalveolar lavage (BAL), and lung biopsy, we have identified 12 new cases of beryllium disease. Each of these individuals had pathologic changes on biopsy, lymphocytic alveolitis on BAL, and positive BAL lymphocyte transformation tests (LTT) in response to beryllium sulfate. This group of patients was remarkable for its paucity of clinical findings. At initial evaluation, seven had no respiratory symptoms, and four had normal physical examinations. Five had no increase in interstitial markings on chest radiograph. In eight cases, flow rates and lung volumes were normal. Diffusing capacity for carbon monoxide was low in only one case, and oxygen exchange during exercise was normal in six of nine subjects studied. In addition to the 12 cases, we evaluated eight beryllium-exposed workers who had other (nonberyllium) lung diseases; two of these eight demonstrated beryllium sensitization based on BAL LTT. We conclude that use of fiberoptic bronchoscopy with transbronchial biopsy and BAL facilitates diagnosis of beryllium workers who have histopathologic and immunologic alterations consistent with chronic beryllium disease. These findings may precede frank clinical illness and physiologic impairment, having important implications for our understanding of the natural history of beryllium disease.

Progressive lung injury over a one-year period after a single inhalation exposure to beryllium sulfate.

The chronic pulmonary toxicity of beryllium sulfate was examined in rats over a 1-yr period after a single, 1-h exposure. Male rats, exposed in a nose-only inhalation chamber to an aerosol of 4.05 micrograms Be/L, were evaluated for lung toxicity by the methods of bronchoalveolar lavage, lung cell kinetics, and histopathologic analysis. Bronchoalveolar lavage activities for alkaline phosphatase (Alk Pase) and acid phosphatase (Ac Pase) were elevated 3 wk after exposure; lactate dehydrogenase (LDH) and Alk Pase activities peaked 3 months after exposure. Histopathologic analysis revealed progressive focal interstitial pneumonitis with a prominent alveolar component of heteromorphic macrophages, neutrophils, and debris. No increase was noted in the overall labeling index in the alveolar cell population at any of the time points sampled. This study demonstrates the effectiveness of bronchoalveolar lavage fluid analysis in monitoring lung damage over a prolonged period and shows that the pulmonary toxicity of beryllium manifests itself as a progressive lesion from a single 1-h inhalation exposure to BeSO4.

Cytochemical study of abnormal intranuclear structures rich in beryllium

During prolonged intoxication with beryllium sulphate, intranuclear beryllium-rich structures (IBRS) develop mainly in the cells of the convoluted tubules of the kidney. These structures are constituted by the accumulation of dense granules approximately 20 nm in diameter. The present work shows: 1) by electron probe microanalysis that IBRS are rich in phosphorus and calcium, and 2) by high resolution ion microanalysis that the granules are rich in beryllium and proteins. Staining with thallium alcoholate and regressive staining with ethylenediaminetetraacetate (EDTA) seem to demonstrate the presence of ribonucleoproteins in the granules. But the richness in calcium and phosphorus makes it difficult to interprete cytochemical reactions based on thallium and lead because complexes can be formed between calcium and thallium or lead, and between phosphorus and lead. Extraction with EDTA and digestion with RNase carried out on floating slices fixed with glutaraldehyde and embedded in glycol methacrylate show that: 1) the positive response of IBRS to cytochemical techniques used seems due solely to calcium; 2) the RNase forms a stable complex with a constituent of the granules that could be the highly phosphorylated acidic protein that binds preferentially to beryllium described by Parker and Stevens.