电感耦合等离子体质谱法(ICP-MS)测定工作场所空气中的铍

目的:建立电感耦合等离子体质谱(ICP-MS)测定工作场所空气中铍的方法。方法:用浓硝酸把滤膜消化完全后用ICP-MS测定,观察测定中工作曲线的相关系数、检出限、精密度和回收率。结果:在一定浓度范围内,方法的标准曲线相关系数1.0000,检出限0.0096μg/L,精密度(RSD)1.7%,回收率99.0%～101%。结论:电感耦合等离子体质谱(ICP-MS)法测定车间空气中的铍,灵敏度高,重现性好,能快速准确的检测出工作场所中铍的含量,可作为检测工作场所空气中金属元素铍的一种快速有效的手段。     

铍针配合中医导引治疗颈型颈椎病的疗效观察

目的观察铍针配合中医导引治疗颈型颈椎病的临床效果。方法颈型颈椎病患者100例随机分为治疗组与对照组各50例。治疗组采用铍针治疗,每5天治疗1次,一般治疗1~3次,同时每天配合中医导引治疗3次,连续2周。对照组采用针刺双侧风池、C4~C6颈夹脊穴及肩井穴,配合颈部一指禅推、捏拿、(?)揉、点按、拍打等常规推拿治疗,隔日1次,每次40 min。比较治疗前后两组患者颈椎日本骨科协会评估(JOA)评分、颈项部疼痛视觉模拟量表(VAS)评分及健康调查简表(SF-36)评分的变化情况。结果治疗后,治疗组JOA评分明显高于对照组(P<0.05);治疗组患者VAS评分显著低于对照组(P<0.01);治疗组总有效率为98.00%,对照组总有效率为86.00%,两组总有效率差异有统计学意义(P<0.05)。治疗后两组的SF-36各维度评分均较治疗前明显提高(P<0.05),而治疗组的SF-36各维度评分均明显高于对照组水平(P<0.05)。结论铍针配合中医导引治疗颈型颈椎病临床疗效确切。     

Structure and reactivity of Ben cycles (n = 3–12): A DFT study

In this paper, we present the electronic and structural study of Be₃–Be₁₂ cycles. In addition, a reactivity study of the Be₃–Be₈ structures toward Li⁺ was carried out, this cation receive electronic density from each cycle. We also evaluated the Be₆ cycle as acceptor of electron density by placing one and two molecules of benzene. The natural bond orbital (NBO) analysis performed shows a clear evidence of those interactions in the six-membered beryllium cycle toward benzene molecules.     

Performance of the beryllium blood lymphocyte proliferation test based on a long-term occupational surveillance program

Objective Data from surveys of the general workforce and new employees at a beryllium manufacturer were used to evaluate the performance of the beryllium blood lymphocyte proliferation test (BeBLPT). Methods Over 10,000 results from nearly 2,400 participants collected over 12 years were analyzed using consistent criteria to describe the performance characteristics of the BeBLPT. Results Approximately 2% of new employees had at least one positive BeBLPT result at the time of hire, and approximately 1% of new employees with no known potential occupational or possible take-home exposures to beryllium were confirmed positive (two positive results) from the time of hire. Positive results were observed in some workers within weeks or months of initial exposure, and the median time to the first positive result in confirmed positive individuals was 5 months. The prevalence of positive BeBLPT results was greatest during the first year of employment with an apparent peak in months 4–8. At least one negative or borderline/negative result was observed in 100% of new workers who underwent follow-up testing after they had been confirmed positive. There was no correlation between time of employment and an increasing prevalence of confirmed positive BeBLPT results in individual surveys; however, the cumulative incidence of confirmed positive results in subsets of workers that participated in multiple surveys increased over time. Conclusion The detection of confirmed positive results in non-occupationally exposed persons, the apparent reversions of previously confirmed positive results, the identification of a positive BeBLPT peak prevalence period, and the variation in intra- and inter-laboratory test methods and interpretation should be considered when interpreting results from studies utilizing the BeBLPT, especially when considering worker-specific interventions. Additional research to refine the BeBLPT or develop a new test is needed to properly characterize the relationship between sensitization and subclinical or clinical indicators of chronic beryllium disease.     

Attenuation of beryllium induced hepatorenal dysfunction and oxidative stress in rodents by combined effect of gallic acid and piperine

We determined a minimum effective dose of gallic acid (3,4,5-trihydroxy benzoic acid; 50 mg/ kg, i.p.) and piperine (10 mg/kg, p.o.) through their therapeutic potential and further evaluated them individually and in combination against beryllium-induced biochemical alterations and oxidative stress consequences in female albino rats. The administration of beryllium altered blood biochemical variables by significantly depleting hemoglobin, albumin and urea, whereas it enhanced bilirubin and creatinine. The release of serum transaminase, lactate dehydrogenase and gamma-glutamyl transpeptidase was significantly greater, and was concomitant with a decrease in serum alkaline phosphatase. A significant increase in lipid peroxidation and a decrease in glutathione, superoxide dismutase and catalase in the liver and kidney was an indication of oxidative stress due to beryllium exposure. Individual administration of gallic acid and piperine moderately reversed the altered biochemical variables, whereas the combination of these was found to completely reverse the beryllium-induced biochemical alterations and oxidative stress consequences. We concluded that gallic acid exerts a synergistic effect when administered with piperine and provides a more pronounced therapeutic potential in reducing beryllium-induced hepatorenal dysfunction and oxidative stress consequences.     

Interactions of mefloquine with ABC proteins, MRP1 (ABCC1) and MRP4 (ABCC4) that are present in human red cell membranes

Human erythrocyte membranes express the multidrug resistance-associated proteins, MRP1, MRP4 and 5, that collectively can efflux oxidised glutathione, glutathione conjugates and cyclic nucleotides. It is already known that the quinoline derivative, MK-571, is a potent inhibitor of MRP-mediated transport. We here examine whether the quinoline-based antimalarial drugs, amodiaquine, chloroquine, mefloquine, primaquine, quinidine and quinine, also interact with erythrocyte MRPs with consequences for their access to the intracellular parasites or for efflux of oxidised glutathione from infected cells. Using inside-out vesicles prepared from human erythrocytes we have shown that mefloquine and MK-571 inhibit transport of 3 microM [(3)H]DNP-SG known to be mediated by MRP1 (IC(50) 127 and 1.1 microM, respectively) and of 3.3 microM [(3)H]cGMP thought but not proven to be mediated primarily by MRP4 (IC(50) 21 and 0.41 microM). They also inhibited transport in membrane vesicles prepared from tumour cells expressing MRP1 or MRP4 and blocked calcein efflux from MRP1-overexpressing cells and BCECF efflux from MRP4-overexpressing cells. Both stimulated ATPase activity in membranes prepared from MRP1 and MRP4-overexpressing cells and inhibited activity stimulated by quercetin or PGE(1), respectively. Neither inhibited [alpha-(32)P]8-azidoATP binding confirming that the interactions are not at the ATP binding site. These results demonstrate that mefloquine and MK-571 both inhibit transport of other substrates and stimulate ATPase activity and thus may themselves be substrates for transport. But at concentrations achieved clinically mefloquine is unlikely to affect the MRP1-mediated transport of GSSG across the erythrocyte membrane.     

Apparent two phase beryllium labelling of hepatic cell nuclei isolated after intravenous administration of beryllium compounds to rats

Cell nuclei are known to possess a high affinity in vitro for the toxic metal beryllium (Be) and the presence of Be in isolated rat liver nuclei has been demonstrated previously after hepatic accumulation of toxic doses of Be compounds. Changes in hepatic nuclear binding of Be has now been examined in rats injected with either particulate (Be phosphate) or soluble (BeSO₄) forms of Be and a common dose and time dependent two phase labelling pattern has been observed in nuclei prepared from both whole liver homogenates and isolated liver parenchymal cells. The initial phase, which is associated with the known acute parenchymal cell necrosis caused by Be, rapidly reaches a maximum at 1–2 days and then declines sharply to minimal levels within 7 days. This is followed by a slower second phase of comparable Be binding observed between 14–24 days which subsequently gradually declines and which occurs when the liver Be content has markedly decreased and no cellular necrosis is evident. These data support the view that nuclear binding of Be is probably not directly involved in the induction of acute cell necrosis and that the early nuclear labelling observed with hepatotoxic doses of Be may be an artefact of the isolation procedure.     

Beryllium sensitization and disease among long-term and short-term workers in a beryllium ceramics plant

OBJECTIVE: Workers at a beryllium ceramics plant were tested for beryllium sensitization and disease in 1998 to determine whether the plant-wide prevalence of sensitization and disease had declined since the last screening in 1992; an elevated prevalence was associated with specific processes or with high exposures; exposure-response relationships differed for long-term workers hired before the last plant-wide screening and short-term workers hired since then. METHODS: Current workers were asked to complete a questionnaire and to provide blood for the beryllium lymphocyte proliferation test (BeLPT). Those with an abnormal BeLPT were classified as sensitized, and were offered clinical evaluation for beryllium disease. Task- and time-specific measurements of airborne beryllium were combined with individual work histories to compute mean, cumulative, and peak beryllium exposures for each worker. RESULTS: The 151 participants represented 90% of 167 eligible workers. Fifteen (9.9% of 151) had an abnormal BeLPT and were split between long-term workers (8/77 = 10.4%) and short-term workers (7/74 = 9.5%). Beryllium disease was detected in 9.1% (7/77) of long-term workers but in only 1.4% (1/74) of short-term workers (P = 0.06), for an overall prevalence of 5.3% (8/151). These prevalences were similar to those observed in the earlier survey. The prevalence of sensitization was elevated in 1992 among machinists, and was still elevated in 1998 among long-term workers (7/40 = 18%) but not among short-term workers (2/36 = 6%) with machining experience. The prevalence of sensitization was also elevated in both groups of workers for the processes of lapping, forming, firing, and packaging. The data suggested a positive relationship between peak beryllium exposure and sensitization for long-term workers and between mean, cumulative, and peak exposure and sensitization for short-term workers, although these findings were not statistically significant. Long-term workers with either a high peak exposure or work experience in forming were more likely to have an abnormal BeLPT (8/51 = 16%) than the other long-term workers (0/26, P = 0.05). All seven sensitized short-term workers either had high mean beryllium exposure or had worked longest in forming or machining (7/55 = 13% versus 0/19, P = 0.18). CONCLUSIONS: A plant-wide decline in beryllium exposures between the 1992 and 1998 surveys was not matched by a decline in the prevalence of sensitization and disease. Similar to findings from other studies, beryllium sensitization/disease was associated with specific processes and elevated exposures. The contrast in disease prevalence between long-term and short-term workers suggests that beryllium sensitization can occur after a short period of exposure, but beryllium disease usually requires a longer latency and/or period of exposure. The findings from this study motivated interventions to more aggressively protect and test workers, and new research into skin exposure as a route of sensitization and the contribution of individual susceptibility.     

Urinary beryllium – a suitable tool for assessing occupational and environmental beryllium exposure?

Objectives: The reasons for the slow progress and lack of new knowledge in the biological monitoring of beryllium (Be) are to be found in the presumed small number of working activities involving exposure to the metal, and the lack of adequate analytical methods. The reference values for urinary Be reported earlier in the literature appear to be too high, due to the poor specificity and sensitivity of the adopted methods. The aim of this study was to correlate Be air concentrations and Be urinary levels to ascertain whether the biological indicator was suitable for assessing occupational exposure to the metal. Methods: To investigate the relationship between the Be concentrations in air and those excreted in urine, we examined 65 metallurgical workers exposed to very low levels of the metal, and 30 control subjects. The exposed workers were employed in two electric steel plants and two copper alloy foundries. The alloys were produced in electric furnaces, starting with scrap containing Be as an impurity. The Be concentrations in the air were monitored by area samplers and the levels of Be in the urine of the workers were determined in samples taken at the end of the shift. Both determinations were carried out by ICP-MS. Results: The median airborne Be concentrations in the copper alloy plants were 0.27 μg/m³ in the furnace area and 0.31 μg/m³ in the casting area. Median values of 0.03 to 0.12 μg/m³ were determined in the steel plants, the relatively wide range probably due to differing amounts of Be in the scrap. Regression analysis was performed on the median values from four work areas and the corresponding urinary samples. A significant correlation was found for the relationship between external and internal exposure. The urinary Be levels were in the range between 0.12 and 0.15 μg/l with observation of the recommended TLV-TWA for inhalable dust of 0.2 μg/m³ (0.2 μg/l at the upper 95th percentile). Conclusions: Sufficient data are not currently available to be able to propose a BEI for urinary Be. Our results show that new investigations are necessary to improve the evaluation of dose indicators and the relationship between external and internal exposure to Be. Received: 15 May 2000 / Accepted: 8 September 2000