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PubMed1991

[Rabbit osteosarcoma induced by hydroxypropylcellulose mixed beryllium oxide pellet--comparison between implantations into bone marrow cavity and into fracture callus of the femur].

Hydroxypropylcellulose mixed beryllium oxide pellets were implanted into the distal metaphysis in the right femurs of 30 rabbits (3 groups, 10 rabbits each): in Group 1 into the internal callus 1 week after production of artificial fracture at a dose of 300 mg, in Group 2 into the bone marrow cavity at a dose of 300 mg, and in Group 3 into the bone marrow cavity at a dose of 50 mg. Osteosarcoma was induced in all of 10 rabbits in Group 1, 7 out of 10 in Group 2, 1 out of 10 in Group 3 at 56 weeks after implantation of BeO. In Group 1, the emergence of tumor and the increase of serum alkaline phosphatase appeared significantly earlier and 80% of the animals with osteosarcoma showed lung metastasis. This experimental method, especially that used in group 1, appears to be useful for the study of human osteosarcoma.

Alkaline Phosphatase↗
PubMed1989

RecA protein-promoted cleavage of LexA repressor in the presence of ADP and structural analogues of inorganic phosphate, the fluoride complexes of aluminum and beryllium.

Complexes formed from A13+ or Be2+ and fluoride inhibit the single-stranded DNA-dependent ATPase activity of RecA protein. In contrast, poly(dT)-RecA-ADP complexes, which are inactive for cleavage of LexA protein, become fully active in the presence of AlF4- or BeF3- ions. These data suggest that fluoride complexes of aluminum and beryllium (called herein X) convert RecA-ADP complexes, which bind weakly to single-stranded DNA, into RecA-ADP-X complexes, which bind tightly to single-stranded DNA, the ADP-X moiety behaving as a nonhydrolyzable analogue of ATP. We propose that AlF4- and BeF3- ions act as analogues of inorganic phosphate by binding to the site of the gamma-phosphate of ATP on RecA-ADP complexes, hence mimicking the single-stranded DNA-RecA-ADP-Pi transition state. We conclude that the elementary reaction that switches RecA protein from a high affinity single-stranded DNA binding state to a low affinity single-stranded DNA binding state is not ATP hydrolysis per se but Pi release.

Adenosine Diphosphate↗
PubMedDate not supplied

Behaviour of urinary beryllium in general population and in subjects with low-level occupational exposure.

Occupational exposure to beryllium (Be) is nowadays much lower than in the past. While the classic Be diseases, such as berylliosis, are clearly on the decline, attention is currently being focussed on the immunological and carcinogenic effects of Be, which suggest that subjects with low-level occupational exposure should also be accurately controlled. Urinary Be (BeU) values were determined in a sample of the general population and in a group of dental technicians exposed to environmental Be concentrations ranging from 0.04 to 1.7 micrograms/m3. The mean BeU values of these workers (0.34 micrograms/l) were higher than those of the general population (0.26 micrograms/l) and the subgroup of dental technicians exposed to higher Be air concentration showed higher BeU levels. Although at present the relationships between external and internal dose and between internal dose and early effects, are not known, we believe that biological monitoring supplies useful information on occupational Be exposure.

Adult↗
PubMed1984

Experimental beryllium-induced lung disease. II. Analyses of bronchial lavage cells in strains 2 and 13 guinea pigs.

In previous studies, we found that endotracheal administration of beryllium oxide (BeO) produced cell-mediated immunity and granulomatous lung disease in strain 2 but not strain 13 guinea pigs. This report describes phenotypic and functional studies of bronchial lavage cells from both guinea pig strains after BeO exposure. In BeO-treated strain 2 animals, the percentage of T (ER+)3 lymphocytes was significantly (p less than 0.05) elevated above normal by 2 weeks after BeO exposure, while T lymphocytes were not increased in strain 13. Giant cells containing crystalline material in fused, coalesced phagolysosomes were observed in treated animals of both strains. BeO-exposed strain 2 alveolar macrophages (AM) demonstrated enhanced killing of Listeria monocytogenes and enhanced chemiluminescence, while AM of strain 13 had responses below controls. Findings support the presence of BeO-induced cellular immunologic activity in strain 2 animals and, on the other hand, suggest BeO toxicity to lavage cells in strain 13.

Animals↗
PubMed1980

[Fluorimetric study of methacycline complex formation with beryllium, aluminum, magnesium, calcium and zinc ions].

Complex formation of metacycline (Pv) with beryllium, aluminium, magnesium, calcium and zinc ions in aqueous solutions was studied fluorometrically. The antibiotic formed the following compounds: CaPv2 (pH 9.45), MgPv (pH 10.40), Be Pv (pH 7.0 and 11), Ca Pv (pH 13.5), Zn Pv (pH 7.15) and Al Pv (pH 6.0). Relationship between the solution fluorescence level and the values of pH, the quantum yield of fluorescence of Pv and the complexes and the kinetics of the reactions of complex formation of Pv with Be and Al were studied. The mechanism of Pv complex formation with the metal ions is discussed. A method for analysis of microgram amounts of Pv in biological fluids was developed. The method is based on the antibiotic fluorescent reaction with magnesium ions.

Aluminum↗
PubMed1995

Modification of radiation sensitivity by salts of the metals beryllium and indium and the rare earths cerium, lanthanum and scandium.

The LD50 of 46 salts of metals and rare earths (lanthanoids) was determined in mice. Half the LD50 of the compounds was then combined with lethal radiation (10.5 Gy) and the modification of survival time was scored. Only the metals beryllium and indium and the rare earths cerium, lanthanum and scandium displayed activity in our assay. They were then tested at a wider range of lower doses and reduced survival time in a dose-dependent fashion. This appears to be compatible with enhancement of radiation sensitivity. The interaction of these metals and rare earths with radiation adds a new facet to their toxicological spectrum and, by enhancing radiation effects, may influence estimates of risk. On the other hand, the radiosensitizing properties of the metals may be useful for further development of compounds to be used as adjuncts in specific situations of cancer radiotherapy.

Animals↗
PubMed1994

Dynamic properties of actin. Structural changes induced by beryllium fluoride.

Beryllium fluoride (BeFx) has been widely used as a phosphate analogue in nucleotide-binding proteins. It was found to bind tightly to F- but not G-actin (Combeau C., and Carlier M. F. (1988) J. Biol. Chem. 263, 17429-17436) and to affect the three-dimensional structure of filaments by stabilizing the subdomain 2 region of the actin promoter (Orlova, A., and Egelman, E. H. (1992) J. Mol. Biol. 227, 1043-1053). In this work we examined the BeFx-induced structural and functional changes in G- and F-actin by using proteolysis, chemical modifications, ATPase, and in vitro motility assays. The results of proteolysis studies show that BeFx binds also to MgADP-G-actin and renders its subdomain 2 region more similar to that in MgATP-G-actin. This is manifested in enhanced subtilisin and decreased tryptic digestions in subdomain 2 of G-actin. BeFx had a strong effect on the proteolysis of MgADP-F-actin: both the tryptic and subtilisin digestions in subdomain 2 were completely inhibited. Significant protection against proteolysis in this region was observed even at 1:14 molar ratios of BeFx to actin indicating cooperative effects on the structure of the actin filament. A similar although milder effect of phosphate on the proteolysis of F-actin suggests that BeFx acts as a phosphate analogue in this system. BeFx also induces changes in the subdomain 1 region of F-actin. This is revealed via reduced rates of Cys-374 alkylation with 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin and an increased subtilisin cleavage near the C terminus of actin in the presence of BeFx. The BeFx-induced structural changes in actin have little effect on its interactions with myosin. BeFx inhibits only slightly the actin-activated ATPase activity of S1 by decreasing Vmax without affecting KM. Additionally, the binding of BeFx to actin does not change the sliding velocity of actin filaments in the in vitro motility assays. The BeFx-induced specific and distinct changes in G- and F-actin point to the dynamic nature of actin structure and the local differences between monomeric and polymeric forms of actin.

Actins↗
PubMed1993

Podoconiosis in the Ethiopian Rift Valley. Role of beryllium and zirconium.

A geogenic origin has been proposed in the aetiology of non-filarial elephantiasis of the feet and legs, recently renamed podoconiosis. Soil collected in an area of the Ethiopian Rift Valley, the borough of Ocholo, known for its high prevalence of podoconiosis (5.06%), has been submitted to mineral analysis. High values of sulphur (S), cerium (Ce), lanthanum (La) and neodymium (Nd), typical for basaltic bedrocks, were found. Of special interest were the values for zirconium (Zr) and beryllium (Be), 618 +/- 87 ppm and 4.6 +/- 0.5 ppm respectively, twice as high as those recorded for soils sampled in neighbouring areas where the prevalence of podoconiosis is low. To be noted also, a high content in vanadium, above 250 ppm, in half of the soil samples collected in this region. Year-long exposure of unprotected feet to Zr and Be, known for their ability to induce granuloma formation in the lymphoid tissue of man, and present in a clay rich in colloidal silica particle, highly abrasive to skin, is doubtlessly a factor involved in the development of lymph node sclerosis leading to elephantiasis.

Adolescent↗
PubMed1995

Chemical etching and EDAX analysis of beryllium-free nickel-chromium ceramo-metal alloy.

A chemical etching technique is described for producing etch patterns in beryllium-free nickel chromium ceramo-metal alloy. Disc-shaped samples were chemically etched, evaluated with SEM and analysed by the EDAX technique. Scanning electron micrographs revealed, profound retentive cavities. The EDAX analysis provided a comprehensive interpretation of the etch mechanism. The obtained results show that the developed chemical etching has the potential to produce a highly retentive etched surface with less problematic and less technique sensitive than electrolytic etching.

Acid Etching, Dental↗
PubMed1997

Comparison of bond strengths of denture base resins to nickel-chromium-beryllium removable partial denture alloy.

PURPOSE: In vitro bond strengths of a traditional denture base resin (Lucitone 199) and three adhesive denture base resins (Meta-Dent, Meta-Fast with liner, and Meta-Fast without liner) to treated nickel-chromium-beryllium (Ni-Cr-Be) partial denture alloy were tested with four alloy surface pretreatments (sandblast, Met-etch, Rocatec with silane, and Rocatec without silane), with or without primer (Dentsply). The Lucitone 199 resin bonded to the nonprimed sandblasted group was the control group. The hypothesis was the use of alloy pretreatments and/or primer does not improve the bond strength of denture base resins to sandblasted Ni-Cr-Be partial denture alloy. MATERIAL AND METHODS: Primed and nonprimed bonded specimens were prepared and finished, stored in 37 degrees C distilled water for 24 hours, then debonded in tension on a testing machine. The bond strength was calculated in megapascals (MPa). Five specimens were prepared and tested for each experimental condition, both with and without primer, for a total of 160 specimens. RESULTS: For three-way analysis of variance, the main effects of resins and treatment were statistically significant (p < 0.05), but the main effect of primer was not statistically significantly (p > 0.05). Without primer, the control group had the lowest bond strength (0 MPa). The three adhesive resin groups produced significantly higher bond strengths than the Lucitone resin groups. For the treated groups, nearly all sandblasted groups produced significantly lower bond strength than the other three treated groups. Meta-Dent to Met-etch treated group had the highest bond strength (23.9 MPa). With primer, the bond strengths of the Lucitone resin groups were significantly higher than the nonprimed groups, and the Lucitone resin-primed Rocatec treated group had the highest bond strength (14.8 MPa). For the three adhesive denture base resins, nearly all primed treated groups had significantly lower bond strengths than nonprimed groups. CONCLUSIONS: Without primer, the Lucitone resin-sandblast treated group (control) had the lowest bond strength (0 MPa). The Meta-Dent denture base resin with the Met-etch treated group had the highest bond strength (23.9 MPa). With primer, the Lucitone resin-primed Rocatec-silane treated group had the highest bond strength (14.8 MPa). For the adhesive denture base resins, nearly all bond strengths of the primed treated groups were significantly lower than the values of the nonprimed groups.

Acid Etching, Dental↗
PubMed1998

Comparison of bond strengths of three denture base resins to treated nickel-chromium-beryllium alloy.

PURPOSE: In-vitro bond strengths of 3 denture base resins (Trutone, Lucitone 199, and Triad) to a nickel-chromium-beryllium removable partial denture alloy (Ticonium) were tested with 3 surface pretreatments: sandblast, acid etch, and Rocatec (silica blasting), with or without primers (Dentsply, CR inlay cement, and Super Bond). MATERIAL AND METHODS: Lucitone 199 denture base resin bonded to the nonprimed sandblasted alloy specimen served as the control group. Alloy specimens were prepared, surface treated, and primed or not primed with primer. The treated specimens were then packed and processed with the denture base resin. Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours, and then debonded in tension. The force at which the bond failed was noted, and bond strength was calculated in megapascals (MPa). Five replications for each condition (180 specimens total) were tested. RESULTS: Significant differences in bond strength were observed with primer, the most important factor, followed by pretreatment and denture base resin. Without primer for all 3 denture base resins, the Met-Etch and Rocatec treated group showed significantly higher bond strengths than the sandblasted groups. For Trutone denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resins. The control group had zero bond strength. For Dentsply primer, the Rocatec treated group bonded to Lucitone 199 resin produced the highest bond strength value (14.8 +/- 1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8 MPa, and 19.3 +/- 1.8 MPa, respectively). For super Bond primer, the Met-Etch treated group for Trutone resin demonstrated the highest bond strength (19.8 +/- 6.2 MPa). CONCLUSIONS: Without primer, the control had the lowest bond strength (0 MPa), and the Trutone groups showed the highest bond strength (11.7 +/- 4.1 MPa). Met-Etch and Rocatec treated groups produced higher bond strengths than the sandblasted groups. The primed specimens demonstrated significantly higher bond strengths than nonprimed specimens, except for Trutone resin, for which primed specimens produced lower bond strengths than the nonprimed specimens.

Acid Etching, Dental↗
PubMed2003

Dissolved and acid available particulate beryllium in eastern UK surface waters.

The concentrations of beryllium (Be) in surface waters are presented for major water quality surveys of eastern UK rivers, based on extensive work within a major environmental programme, the Land Ocean Interaction Study (LOIS). Two measurements were made, one for dissolved Be (i.e. the fraction that can pass through 0.45-microm membrane filters) the other for acid available total Be (dissolved Be plus the fraction of particulate Be that can be leached by a 1% v/v concentrated nitric acid solution). Dissolved Be concentrations are generally less than 1 microg l(-1) with a mean of approximately 0.02 microg l(-1), but higher values occur across the eastern UK rivers between 16th October and 7th November 1995 under neutral to alkaline conditions where Be would not be expected to be mobile. The higher values vary from river to river and there is a marked increase from north to south with particularly high concentrations (up to 29 microg l(-1)) for the industrial and urban impacted rivers of the southern Humber basin. The results show a major increase in dissolved Be at a time of exceptional drought conditions and climate instability, which seems to be linked to industrial/urban catchment systems. The average dissolved Be flux is 0.22 gha(-1) year(-1) with a range in mean across the sites of 0.08-0.45 gha(-1) year(-1). Without the period of enhanced Be concentrations, the Be flux through the period would have been approximately 40% less. There is no clear distinction between the dissolved Be flux for the rural and urban/industrial catchment systems. Acid available particulate Be (AAPBe) concentrations are low across the eastern UK rivers, they range between 0 and 1.33 microg l(-1) with a mean of 0.02 microg l(-1) and the highest concentrations occur for the industrial/urban rivers (approximately twice the levels occurring within the rural rivers). The AAPBe concentrations are linearly correlated with the concentrations of suspended sediment, particulate organic carbon, particulate nitrogen, particulate phosphorus, and the AAP for several transition metals (Al, Co, Cr, Fe, Mn, Ni and Y), and the lanthanides. This reflects the nature of the catchment sources of particulate material (soil erosion and pollutant sources) and the hydrogeochemistry of Be with the high potential for hydrolysis and hydrogen bonding due to its small atomic size and high surface charge density. The acid available particulate flux averages approximately 0.42 gha(-1) year(-1) with a range in mean across the sites of 0.14-1.2 gha(-1) year(-1). The highest flux occurs for a river with a flood plain contaminated by spoil from historic mining of lead-zinc deposits, but there is no clear separation between the rural and the industrial/urban impacted catchments. The results indicate a potential and most unexpected dissolved Be stress to lowland aquatic environments, a stress that might well increase over time for the UK given the increasing climate instability within the country. The findings are linked to other information on Be in surface waters for other UK surface waters, including previously unpublished data, to allow a broader perspective for UK riverine environments. Information is provided on Be levels in acidic upland streams in mid Wales (upper River Severn), other eastern UK rivers (collected towards the end of the LOIS initiative) and drainage waters from a disused tin wine in Cornwall (Wheal Jane Mine).

Journal Article↗
PubMed2005

Novel binding of beryllium to dicarboxyimidazole-based model compounds and polymers.

The ligand 4,5-dicarboxyimidazole (H(2)DCI) and its methyl derivative 1-methyl-4,5-dicarboxyimidazole (H(2)MDCI) have been shown to bind to Be(II) forming a zwitterionic species that has been structurally characterized. A new dicarboxyimidazole-based polymer has been prepared and its Be-binding properties have been studied using NMR ((1)H and (9)Be) and fluorescence spectroscopy; it represents a rare example of beryllium binding to a polymer. Models of the mononuclear and polymeric Be(II)-binding sites have been studied using density functional theory (DFT), and the (9)Be NMR chemical shifts of these model materials have been calculated for the purpose of direct comparison to experimentally observed values. Differences in the binding modes of the mononuclear and polymeric species are discussed.

Journal Article↗
PubMed2006

Syntheses and structures of two low-dimensional beryllium phosphate compounds: [C5H14N2]2[Be3(HPO4)5].H2O and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5H2O.

The first two low-dimensional beryllium phosphates, [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29) and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), have been successfully synthesized under mild hydrothermal/solvothermal conditions. BePO-CJ29 is built up from strict alternation of BeO4 and HPO4 tetrahedra forming a unique one-dimensional double chains with 12-ring apertures. There are pseudo-10-ring apertures enclosed by two double chains through H-bonds. BePO-CJ29 can also be viewed as a pseudo 2-D layered structure stabilized by strong H-bonds. The diprotonated 2-methylpiperazium cations are located at three positions (i.e., inside the 12-ring aperture, inside the pseudo-10-ring aperture, and in the interlayer of the inorganic pseudo-layers. BePO-CJ30 is constructed by the alternation of Be-centered tetrahedra (including BeO4 and HBeO4) and P-centered tetrahedra (including PO4 and HPO4) resulting in a two-dimensional layered structure parallel to the (0 1 1) direction. The complex layer is composed of coupled 4.8 net sheets. The diprotonated 1,6-hexandiamine cations and water molecules reside in the interlayer regions and interact with the inorganic layers through H-bonds. Crystal data are as follows: [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29), triclinic, P1 (No. 2), a = 8.1000(9) A, b = 8.4841(14) A, c = 19.665(2) A, alpha = 89.683(10) degrees, beta = 78.182(8) degrees, gamma = 87.932(9) degrees, V = 1321.9(3) A3, Z = 2, R1 = 0.0523 (I > 2sigma(I)), and wR2 = 0.1643 (all data); [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), orthorhombic, Pccn (No. 56), a = 26.01(4) A, b = 8.431(12) A, c = 9.598(13) A, V = 2105(5) A3, Z = 8, R1 = 0.0833 (I > 2sigma(I)), and wR2 = 0.2278 (all data).

Journal Article↗
PubMed1997

Beryllium Chelation by Dicarboxylic Acids in Aqueous Solution.

Maleic and phthalic acids are found to react with Be(OH)(2), generated in situ from BeSO(4)(aq) and Ba(OH)(2)(aq), in aqueous solution at pH 3.0 or 4.4, respectively (25 degrees C), to give solutions containing the complexes (H(2)O)(2)Be[(OOCCH)(2)] (1) and (H(2)O)(2)Be[(OOC)(2)C(6)H(4)] (3). The products can be isolated in high yield and identified by microanalytical data. With 2 equiv of the dicarboxylic acids and the pH adjusted to 5.5 and 5.9, respectively, by addition of ammonia, the bis-chelate complexes [(NH(4))(+)](2){[Be[(OOCCH)(2)](2)}(2)(-) (2) and [(NH(4))(+)](2){Be[(OOC)(2)C(6)H(4)](2)}(2)(-) (4) are obtained, which can also be isolated. The compounds show distinct (9)Be, (1)H, and (13)C resonances in their NMR spectra in aqueous solutions. Layering of an aqueous solution of compound 4 with acetone at ambient temperature leads to the precipitation of single crystals suitable for an X-ray structure determination. This salt (5) was found to contain the bis-chelated dianion {Be[(OOC)(2)C(6)H(4)](2)}(2)(-) with the beryllium atom in the spiro center of two seven-membered rings and an overall geometry approaching closely C(2) symmetry. These anions are associated with two crystallographically independent but structurally similar counterions [MeC(O)CH(2)CMe(2)NH(3)](+), which are the product of a condensation reaction of the ammonium cation with the acetone solvent. In the crystal the ammonium hydrogen atoms of the cations form N-H.O hydrogen bonds with the oxo functions of the dianion.

Journal Article↗
PubMed2006

A density functional study on beryllium-doped carbon dianion clusters CnBe2- (n = 4-14).

Making use of the software of molecular graphics, we designed numerous models of C(n)()Be(2-) (n = 4-14). We carried out geometry optimization and calculation on vibration frequency by means of the B3LYP density functional method. After comparison of structure stability, we found that the ground-state isomers of C(n)()Be(2-) (n = 4-14) are linear with the beryllium atom located inside the C(n)() chain. When a side carbon chain is with an even number of carbon atoms, it is polyacetylene-like, whereas when a side chain is with an odd number of carbon atoms, it is cumulene-like. The C(n)Be(2-) (n = 4-14) clusters with an even number of carbon atoms are more stable than that with an odd number of carbon atoms, matching the peak pattern observed in accelerator mass spectrometry (AMS) and Coulomb Explosion Imaging (CEI) investigations of C(n)()Be(2-) (n = 4-14). The trend of such odd/even alternation is explained based on concepts of bonding characteristics, electronic configuration, electron detachment, and incremental binding energy.

Journal Article↗
PubMed2004

Structural and electronic properties of small beryllium clusters: a theoretical study.

Geometric structures and electronic properties of small beryllium clusters (Be(n), 2< or = n< or =9) are investigated within the gradient-corrected density functional theory. The computations are performed with the Becke exchange and Perdew-Wang correlation functionals. Both low and high multiplicity states are considered. A predominance of higher multiplicity states among the low-energy isomers of the larger clusters is found. An analysis of the variations in the structural and electronic properties with cluster size is presented, and the results are compared with those of earlier studies.

Journal Article↗