International round robin tests on the measurement of carbon in diesel exhaust particulates

Object: Diesel soot has been recognized as probably carcinogenic to humans. Elemental carbon (also called black carbon) in soot is considered at the moment as the most significant surrogate to be measured for assessing the exposure to this pollutant. Its analysis is done by combustion in an oven and determination of the CO₂ formed, after elimination of the organic fraction of the soot by heating and/or by solvent extraction. The analysis allows determination of both fractions of the soot: “elemental carbon” (EC) and organic carbon␣(OC). The sum of EC and OC is called TC (total carbon). Method: An informal European coordination group organized two round robin tests on filter samples collected from diluted diesel emissions. The first round (RRT1) was performed on 13 different samples analyzed by ten laboratories. The range of loading was 2.5 to 150 μg/cm² of EC. No evaluation of the precision within laboratories could be made since each laboratory gave only one result per sample. Therefore a second round (RRT2) was organized with two samples and a blank filter sent in several portions to 11 laboratories. It should be stressed that each laboratory used its own method and that no standardization was planned at this stage. Results: Results of RRT1 showed that the coefficient of variation between laboratories decreased with higher loading and was around 10% to 15% for EC above about 20 μg/cm². Dispersion of the results varied and it appeared that the way OC is removed from the soot is probably the most important factor of influence. The correlation between the laboratories was good as a whole but some systematic differences could be detected. Besides the different techniques to remove the organic carbon, the pretreatment of the filter by HCl (either as a vapor or as a solution) to remove the inorganic carbonates (potential interference sources), is probably also a significant factor of influence in the dispersion of the results between laboratories. It is not yet clear from these results whether the “environmental” laboratories give different results from the “occupational” laboratories, but it is clear that their objectives differ since for the “environmentalists”, EC is not a specific marker of diesel immissions, in contrast to the “occupationalists”. Conclusion: It can be concluded that, although significant differences exist between laboratories they can be attributed mainly to the narrow distribution of the results within a single laboratory, and that the overall agreement of the results for EC and TC is fairly good. These results obtained with pure diesel engine emissions, should be complemented by field samples, but they have already achieved relevant findings in the performance of the procedures used to assess exposure to diesel soot. Received: 30 December 1996 / Accepted: 21 February 1997     

Evidence of clonotypic pattern of T-cell repertoire in synovial fluid of children with juvenile rheumatoid arthritis at the onset of the disease

Rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) are characterized by chronic inflammation, synovial cell proliferation and progressive joint damage. It has been speculated that T cells play an important role in the pathogenesis of RA and JRA in the early stage of the disease. Previous studies have demonstrated discrepant results regarding the significance of T-cell clonality in RA or JRA lesions. It can be postulated that the heterogeneity of these data may be linked to the stage of the disease, as the relative importance of selective immunological events is different during the time from onset to established disease. To avoid this problem, we conducted the present study in nine children affected by JRA at the onset of the disease and before treatment. We analysed the T-cell receptor beta chain variable (TCRBV) of CD4+ and CD8+ lymphocytes in peripheral blood (PBL) and synovial fluid (SFL), by a panel of monoclonal antibodies (MoAbs). Furthermore, to assess the clonotypic pattern of T-cell repertoire, the CDR3 length distribution was evaluated by spectratyping analysis. Our results showed no significant expansion of distinct TCRBV subset in either synovial or peripheral compartments. Conversely, when we studied the CDR3 length distribution, an oligoclonal pattern was found in the SFL of six patients, suggesting the presence of a clonotypic restriction of T cells in SFL, which is not detectable in PBL. These findings are consistent with an antigen driven T-cell expansion sequestered at the inflammatory site.     

Nosocomial and community acquired uropathogenic isolates of Proteus mirabilis and antimicrobial susceptibility profiles at a university hospital in Sub–Saharan Africa

ObjectiveTo ascertain antimicrobial susceptibility profile of Proteus mirabilis (P. mirabilis) from clinical urine specimens at a university hospital in the spate of its recorded increasing resistance patterns.MethodsThe study was retrospective in nature. Data generated from urine cultures of patients at University of Calabar Teaching Hospital for a period of five years (2004–2009) were compiled. Relevant information obtained were age and gender of patients, organisms recovered and their antibiotic susceptibility patterns. P. mirabilis was identified using standard laboratory procedures.ResultsP. mirabilis showed the highest resistance against ampicillin, cloxacillin, amoxicillin, tetracycline, co-trimoxazole, erythromycin and chloramphenicol (100%–37.2%) while colistin, ofloxacin, ciprofloxacin, ceftriaxone, nalidixic acid and nitrofurantoin recorded the highest activity (59.1%–96.9%) with no drug recording 100% activity. The resistance of the nosocomial isolates of the organism were significantly higher than the community acquired isolates against that of the common antibiotics in use (P<0.05).ConclusionsExtreme caution should be exercised in antibiotic administration in hospital setting and the potential benefits adequately assessed while control of nosocomial infections be given a priority so as to limit the spread of resistant bacteria.     

G-protein coupled receptors in lipid rafts and caveolae: how, when and why do they go there?

This review describes the advances in our understanding of the role of G-protein coupled receptor (GPCR) localisation in membrane microdomains known as lipid rafts and caveolae. The growing interest in these specialised regions is due to the recognition that they are involved in the regulation of a number of cell functions, including the fine-tuning of various signalling molecules. As a number of GPCRs have been found to be enriched in lipid rafts and/or caveolae by means of different experimental approaches, we first discuss the pitfalls and uncertainties related to the use of these different procedures. We then analyse the addressing signals that drive and/or stabilise GPCRs in lipid rafts and caveolae, and explore the role of rafts/caveolae in regulating GPCR trafficking, particularly in receptor exo- and endocytosis. Finally, we review the growing evidence that lipid rafts and caveolae participate in the regulation of GPCR signalling by affecting both signalling selectivity and coupling efficacy.     

TLIF术式在布氏杆菌性脊柱炎病人中的临床疗效及安全性分析

目的 对比分析单纯后路内固定+一期经腰椎间孔病椎间病灶清除(TLIF)与经典的前后联合手术在布氏杆菌性脊柱炎患者中的临床疗效及安全性。 方法 对我院2015年1月至2017年12月收治的93例布病性脊柱炎患者的临床资料进行分析。按手术方式分为观察组(45例)和对照组(48例)。对两组患者的基础数据、临床指标、术前术后各项指标水平以及术后并发症、植骨治愈情况。 结果 观察组与对照组基础数据比较,差异无统计学意义(P>0.05)。观察组患者的手术时间、住院天数、术中出血量及术后下床时间均明显低于对照组(P<0.01)。两组患者术后3个月的ODI、VAS、CRP、ESR及Cobb角均明显低于术前(P<0.05);术后3个月,观察组患者的ODI、VAS、CRP、ESR及Cobb角均明显低于对照组(P<0.05)。观察组术后并发症发生率(4.4%)明显低于对照组(25.0%)(Χ²=7.674,P<0.01)。 结论 TLIF治疗布氏杆菌性脊柱炎患者的临床疗效突出,安全性较好,更有利于患者术后身体的恢复。