Implementation of ISO 9002 for research in occupational epidemiology

 The Department of Epidemiology, which forms part of the French National Institute for Research and Safety (INRS), is involved in research on occupational risks. It provides results of industry-based epidemiological studies focused on the relationship between occupational exposure and diseases of the respiratory system, central and peripheral nervous systems and cancer. This paper describes the Quality Assurance System developed by our department, which has been successfully maintained and extended since being granted ISO 9002 certification by the French Association for Quality Assurance. The quality system includes procedures specific to epidemiological study conduct and scientific peer reviews. It has been designed in order to meet the required ISO elements, including quality aims and policy, quality procedures for management of personnel, sub-contractors and facilities, nonconformities, corrective and preventive actions, archiving and traceability and planning of internal quality audits. Improvements in management, technical and service quality have resulted from this process. Although epidemiological studies differ markedly from industrial production for which the standards were originally drawn up, we have found that Quality Assurance is both applicable and useful in epidemiological research on occupational risks. Therefore, we conclude that a certified Quality Assurance Scheme including scientific peer reviews can be recommended to ensure reliable epidemiological results. Received: 22 July 1998 · Accepted: 5 October 1998     

A new method for analyzing H5N1 avian influenza virus

In this paper a novel method for phylogenetic analysis of H5N1 avian influenza virus has been proposed. At first we provide a mapping of virus protein sequence. Based on this mapping, we propose a new distance measure and make use of the corresponding similarity matrix to construct phylogenic tree without requiring multiple alignment. As an application, we construct phylogenic tree for 123 species of H5N1 avian influenza virus. The phylogeny obtained is generally consistent with evolutionary trees constructed in previous studies.     

Theoretical analysis of binding specificity of influenza viral hemagglutinin to avian and human receptors based on the fragment molecular orbital method

The hemagglutinin (HA) protein of the influenza virus binds to the host cell receptor in the early stage of viral infection. A change in binding specificity from avian 2-3 to human 2-6 receptor is essential for optimal human-to-human transmission and pandemics. Therefore, it is important to reveal the key factors governing the binding affinity of HA-receptor complex at the molecular level for the understanding and prediction of influenza pandemics. In this work, on the basis of ab initio fragment molecular orbital (FMO) method, we have carried out the interaction energy analysis of HA-receptor complexes to quantitatively elucidate the binding specificity of HAs to avian and human receptors. To discuss the binding property of influenza HA comprehensively, a number of HAs from human H1, swine H1, avian H3 and avian H5 viruses were analyzed. We performed detailed investigations about the interaction patterns of complexes of various HAs and receptor analogues, and revealed that intra-molecular interactions between conserved residues in HA play an important role for HA-receptor binding. These results may provide a hint to understand the role of conserved acidic residues at the receptor binding site which are destabilized by the electrostatic repulsion with sialic acid. The calculated binding energies and interaction patterns between receptor and HAs are consistent with the binding specificities of each HA and thus explain the receptor binding mechanism. The calculated results in the present analysis have provided a number of viewpoints regarding the models for the HA-receptor binding specificity associated with mutated residues. Examples include the role of Glu190 and Gln226 for the binding specificity of H5 HA. Since H5 HA has not yet been adapted to human receptor and the mechanism of the specificity change is unknown, this result is helpful for the prediction of the change in receptor specificity associated with forthcoming possible pandemics.     

Label‐Free Detection of Glycan–Protein Interactions for Array Development by Surface‐Enhanced Raman Spectroscopy (SERS)

A glyco‐array platform has been developed, in which glycans are attached to plasmonic nanoparticles through strain‐promoted azide‐alkyne cycloaddition. Glycan–protein binding events can then be detected in a label‐free manner employing surface‐enhanced Raman spectroscopy (SERS). As proof of concept, we have analyzed the binding of Gal1, Gal3, and influenza hemagglutinins (HAs) to various glycans and demonstrated that binding partners can be identified with high confidence. The attraction of SERS for optical sensing is that it can provide unique spectral signatures for glycan–protein complexes, confirm identity through statistical validation, and minimizes false positive results common to indirect methods. Furthermore, SERS is very sensitive and has multiplexing capabilities thereby allowing the simultaneous detection of multiple analytes.     

四氢萘与香豆素反应研究——Ⅰ. 供氢溶剂下香豆素和氢化香豆素反应行为研究

本实验证明了: (1)香豆素和四氢萘反应生成氢化香豆素; 2)氢化香豆素是一种比较稳定的产物, 但在一定条件下可以进一步反应生成其它产物。文中给出了应用多种方法对中间物及产物的分析结果。动力学实验及产物分析结果表明氢化香豆素的大多数反应步骤是按连串反应进行。本文提出的反应机理较好地解释了实验现象。     

低浓度甲醛对多肽和蛋白化学修饰的质谱研究

采用基质辅助激光解析电离飞行时间质谱( MALDI-TOF MS)和纳升电喷雾四极杆飞行时间串联质谱( Nano-ESI -QTOF MS)技术,以标准肽段和流感病毒基质蛋白酶切肽段为模型,研究了甲醛对蛋白质和多肽主链的修饰作用。采用与实际病毒灭活过程一致的实验条件(4℃,0.025%(V/V)福尔马林(37%(w/w)甲醛溶液)处理72 h),进行甲醛与多肽的化学反应。结果表明,在实验条件下,甲醛能与标准肽段N端的氨基反应生成羟甲基加合物,再发生缩合反应生成亚胺,形成+12 Da的产物。此外,甲醛还能与标准肽段中的精氨酸、赖氨酸的侧链发生反应,生成+12 Da的反应产物。对流感病毒基质蛋白的酶切肽段与甲醛的反应的质谱分析结果显示,多数的肽段都生成了+24 Da的产物,质量的增加来源于肽段N端氨基(+12 Da)和C端精氨酸或赖氨酸的侧链(+12 Da)的贡献。此外,还观察到有一个漏切位点的肽段生成了+36 Da的产物。本研究结果表明,在实验条件下,低浓度甲醛主要与肽段和蛋白的N 端氨基,以及精氨酸和赖氨酸侧链发生反应。本研究为分析低浓度甲醛与蛋白质的反应产物提供了有效的质谱分析方法和解谱依据。     

Rapid separation and identification of the subtypes of swine and equine influenza A viruses by electromigration techniques with UV and fluorometric detection

Influenza A is viral disease, which is a cause of yearly epidemics and, potentially, pandemics. The conventional techniques used today are equipment-demanding, time-consuming and laborious. Recently, we have confirmed that the capillary isoelectric focusing is a suitable fast alternative for the verifying of virus purity. In the wide pH gradient of pH range 2.0-7.5 the isoelectric points for subtypes of equine (H3N8) and swine (H1N2) influenza A viruses were determined approximately as 6.6 and 6.5, respectively. In this contribution we have verified these findings using different isolates of different viral subtypes of swine influenza, H1N1, H1N2, and of equine influenza, H3N8, H7N7, which were separated by capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF) in the narrow pH gradient pH range from 6.0 to 7.0. It was found that the isoelectric points of different isolates and subtypes of equine and swine influenza are almost independent of their origin. The electromigration velocities of subtypes of equine or swine influenza viruses were dependent on the antigenic subtypes of their surface glycoproteins. The detection sensitivity of the influenza viruses labeled by the fluorescent non-ionogenic tenside based on poly(ethylene glycol)pyrenebutanoate for fluorometric detection was increased and down to ten labeled viruses were detected. The isoelectric points of the native and labeled equine and swine influenza A viruses and their subtypes do not differ. According to our experiments these methods appear to be useful for the fast preliminary differentiation of influenza viruses in future.     

A new mechanistic Parachor model to predict dynamic interfacial tension and miscibility in multicomponent hydrocarbon systems

Widely used traditional Parachor model fails to provide reliable interfacial tension predictions in multicomponent hydrocarbon systems due to the inability of this model to account for mass transfer effects between the fluid phases. In this paper, we therefore proposed a new mass transfer enhanced mechanistic Parachor model to predict interfacial tension and to identify the governing mass transfer mechanism responsible for attaining the thermodynamic fluid phase equilibria in multicomponent hydrocarbon systems. The proposed model has been evaluated against experimental data for two gas-oil systems of Rainbow Keg River and Terra Nova reservoirs. The results from the proposed model indicated good IFT predictions and that the vaporization of light hydrocarbon components from crude oil to gas phase is the governing mass transfer mechanism for the attainment of fluid phase equilibria in both the gas-oil systems used. A multiple linear regression model has also been developed for a priori prediction of exponent in the mechanistic model by using only the reservoir fluid compositions, without the need for experimental measurements. The dynamic nature of interfacial tensions observed in the experiments justifies the use of diffusivities in the mechanistic model, thus enabling the proposed model predictions to determine dynamic gas-oil miscibility conditions in multicomponent hydrocarbon systems.     

Label-free, arrayed sensing of immune response to influenza antigens

Periodic outbreaks of pandemic influenza have been a devastating cause of human mortality over the past century. More recently, an avian influenza strain, designated H5N1, has been identified as having the potential to cause a zoogenic pandemic in humans, and a current outbreak of a new H1N1 influenza variant hypothesized to be of swine origin is of considerable concern. In order to facilitate surveillance and the rapid assessment and comparison of vaccination efforts, a high-throughput assay is highly desirable to supplement standard methods, which require high biosafety-level facilities. In this paper, we describe the design, production, and preliminary evaluation of an antigen array incorporating a panel of hemagglutinins as a platform for the detection and rapid quantification of influenza-specific antibodies in human serum by Arrayed Imaging Reflectometry (AIR), a label-free optical biosensor.     

Discovery of New Ginsenol-Like Compounds with High Antiviral Activity

A number of framework amides with a ginsenol backbone have been synthesized using the Ritter reaction. We named the acetamide as Ginsamide. A method was developed for the synthesis of the corresponding amine and thioacetamide. The new compounds revealed a high activity against H1N1 influenza, which was confirmed using an animal model. Biological experiments were performed to determine the mechanism of action of the new agents, a ginsamide-resistant strain of influenza virus was obtained, and the pathogenicity of the resistant strain and the control strain was studied. It was shown that the emergence of resistance to Ginsamide was accompanied by a reduction in the pathogenicity of the influenza virus.     

Alpha particle absorption and inclined incidence track parameters evaluation in plastic detectors

In this work the use of our recently constructed irradiation chamber was involved in the current experiments. The absorption of alpha particle in air has been studied through a set of experiments in which the stopping power has been measured. A comparison between the calculated values and the present experimental results is given and a good agreement has been found. Critical angle (θ_c) determination has been carried out using two different techniques, via indirect and direct measurements, under different etching conditions and at various alpha energies. An empirical fit of θ_c−h (h is the removal thickness layer) dependence has been calculated and found to work well in the studied h ranges. Also, the inclined alpha tracks parameters of energies between 1.0 and 5.0 MeV have been studied. Results can be successfully applicable in alpha autoradiography studies and detector efficiency determination for track registration in plastic recorders.     

Kinetic stability of 1,1,1-Trifluoroethane

1,1,1-Trifluoroethane has been decomposed in comparative rate single-pulse shock-tube experiments. The rate expression for elimination at ca. 2.5 bar and in the temperature range of 1050 to 1200 K has been found to be The experimental conditions appear to be such that the unimolecular reaction is at the beginning of the fall-off region and we find that for step sizes down between 500 and 1000 cm⁻¹ the high-pressure rate expression is in the range where the smaller rate parameters refer to the larger step size down. The results are compared with those from an earlier study and the anomalously high A-factor is noted. It is suggested that the existing rate expressions for the fluorinated ethanes may need to be reevaluated. © 1998 John Wiley & Sons, Inc., Int J Chem Kinet: 30: 621–628, 1998     

Electrochemical Assay to Detect Influenza Viruses and Measure Drug Susceptibility

An electrochemical assay has been designed to rapidly diagnose influenza viruses. Exposure of a glucose‐bearing substrate to influenza viruses or its enzyme, neuraminidase (NA), releases glucose, which was detected amperometrically. Two methods were used to detect released glucose. First, we used a standard glucose blood meter to detect two viral NAs and three influenza strains. We also demonstrated drug susceptibility of two antivirals, Zanamivir and Oseltamivir, using the assay. Finally, we used disposable test strips to detect nineteen H1N1 and H3N2 influenza strains using this assay in one hour. The limit and range of detection of this first generation assay is 10² and 10²–10⁸ plaque forming units (pfu), respectively. Current user‐friendly glucose meters can be repurposed to detect influenza viruses.     

Origin of asymmetric charge partitioning in the dissociation of gas-phase protein homodimers

The origin of asymmetric charge and mass partitioning observed for gas-phase dissociation of multiply charged macromolecular complexes has been hotly debated. These experiments hold the potential to provide detailed information about the interactions between the macromolecules within the complex. Here, this unusual phenomenon of asymmetric charge partitioning is investigated for several protein homodimers. Asymmetric charge partitioning in these ions depends on a number of factors, including the internal energy, charge state, and gas-phase conformation of the complex, as well as the conformational flexibility of the protein monomer in the complex. High charge states of both cytochrome c and disulfide-reduced alpha-lactalbumin homodimers dissociate by a symmetrical charge partitioning process in which both fragment monomers carry away roughly an equal number of charges. In contrast, highly asymmetric charge partitioning dominates for the lower charge states. Cytochrome c dimer ions with eleven charges formed by electrospray ionization from two solutions in which the solution-phase conformation differs dissociate with dramatically different charge partitioning. These results demonstrate that these gas-phase complexes retain a clear "memory" of the solution from which they are formed, and that information about their solution-phase conformation can be obtained from these gas-phase dissociation experiments. Cytochrome c dimer ions formed from solutions in which the conformation of the protein is native show greater asymmetric charge partitioning with increasing ion internal energy. Cytochrome c dimers that are conformationally constrained with intramolecular cross-linkers undergo predominantly symmetric charge partitioning under conditions where asymmetric charge partitioning is observed for cytochrome c dimers without cross-links. Similar results are observed for alpha-lactalbumin homodimers. These results provide convincing evidence that the origin of asymmetric charge partitioning in these homodimers is the result of one of the protein monomers unfolding in the dissociation transition state. A mechanism that accounts for these observations is proposed.     

The unusual reaction of semiquinone radicals with molecular oxygen

Hydroquinones (benzene-1,4-diols) are naturally occurring chain-breaking antioxidants, whose reactions with peroxyl radicals yield 1,4-semiquinone radicals. Unlike the 1,2-semiquinone radicals derived from catechols (benzene-1,2-diols), the 1,4-semiquinone radicals do not always trap another peroxyl radical, and instead the stoichiometric factor of hydroquinones varies widely between 0 and 2 as a function of ring-substitution and reaction conditions. This variable antioxidant behavior has been attributed to the competing reaction of the 1,4-semiquinone radical with molecular oxygen. Herein we report the results of experiments and theoretical calculations focused on understanding this key reaction. Our experiments, which include detailed kinetic and mechanistic investigations by laser flash photolysis and inhibited autoxidation studies, and our theoretical calculations, which include detailed studies of the reactions of both 1,4-semiquinones and 1,2-semiquinones with O2, provide many important insights. They show that the reaction of O2 with 2,5-di-tert-butyl-1,4-semiquinone radical (used as model compound) has a rate constant of 2.4 +/- 0.9 x 10(5) M-1 s-1 in acetonitrile and as high as 2.0 +/- 0.9 x 10(6) M-1 s-1 in chlorobenzene, i.e., similar to that previously reported in water at pH approximately 7. These results, considered alongside our theoretical calculations, suggest that the reaction occurs by an unusual hydrogen atom abstraction mechanism, taking place in a two-step process consisting first of addition of O2 to the semiquinone radical and second an intramolecular H-atom transfer concerted with elimination of hydroperoxyl to yield the quinone. This reaction appears to be much more facile for 1,4-semiquinones than for their 1,2-isomers.     

Nanotherapeutic Anti-influenza Solutions: Current Knowledge and Future Challenges

Nanotechnology has impacted every aspect of human life and the environment. The raising concern against influenza outbreaks is an ongoing issue. With the current drugs and natural remedies, some amount of resolution has been reached. Yet, nothing conclusive has been achieved. With every resource tapped, it is now time to combine strategies. This review highlights the low enthusiasm in this area, where not much has been probed into employing nanomaterials into influenza research. The achievements made through the intervention of nanotechnology into anti influenza research, has been surveyed in this review. Except for a few, not much progress was evidenced. Although significant progress has been achieved with nano inputs, yet nothing much has been done in this direction. This review emphasizes the need to combine strategies and find new remedies against influenza virus using nano platforms. New directions and future perspectives for accessing the nano inputs for combating the influenza issues have been discussed.     

Coherence transfer via longitudinal spin order generalized pulse pair filtering for pure phase two-dimensional NMR spectroscopy

A generalized pulse pair has been suggested in which the longitudinal spin order is retained and the transverse components cancelled by random variation of the interval between pulses, in successive applications of the two-dimensional NMR algorithm. This method leads to pure phases and has been exploited to provide a simpler scheme for two-spin filtering and for pure phase spectroscopy in multiple-quantum-filtered two-dimensional NMR experiments.