Heterogeneity and spatial distribution of bacterial background contamination in pulp and process water of a paper mill.

Identifying the source and the distribution of bacterial contaminant communities in water circuits of industrial applications is critical even when the process may not show signs of acute biofouling. The endemic contamination of facilities can cause adverse effects on process runability but may be masked by the observed daily variability. The distribution of background communities of bacterial contaminants may therefore be critical in the development of new site-specific antifouling strategies. In a paper mill as one example for a full-scale production process, bacterial contaminants in process water and pulp suspensions were mapped using molecular fingerprints at representative locations throughout the plant. These ecological data were analyzed in the process-engineering context of pulp and water flow in the facilities. Dispersal limits within the plant environment led to the presence of distinct groups of contaminant communities in the primary units of the plant, despite high flows of water and paper pulp between units. In the paper machine circuit, community profiles were more homogeneous than in the other primary units. The variability between sampled communities in each primary unit was used to identify a possible point source of microbial contamination, in this case a storage silo for reused pulp. Part of the contamination problem in the paper mill is likely related to indirect effects of microbial activity under the local conditions in the silo rather than to the direct presence of accumulated microbial biomass.

Seroepidemiology of Helicobacter pylori infection in Guadeloupe.

854 sera collected from blood donors in Guadeloupe were screened for Helicobacter pylori immunoglobulin G antibodies by a commercial enzyme-linked immunosorbent assay kit. The overall prevalence was 55.2%; it increased significantly with age from 36.1% at 18-19 years to 63.7% at 50-59 years (P = 0.003).

Prenatal transmission of dengue: two new cases.

Dengue is commonly observed in most tropical countries, but its transmission from mother to fetus has not been frequently described. We report two such cases. The first signs of dengue in the infants appeared on the 3rd and 9th days of life. In both, a bacterial infection was suspected initially. In areas where it is endemic, the diagnosis of dengue should be considered in the neonate with signs of bacterial infection. When dengue is suspected in a pregnant woman, laboratory investigation and extended observation of the newborn are advised.

Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium

The increasing use of alcohol as an alternative fuel to gasoline or diesel can increase emission of formaldehyde, an organic gas that is irritant to the mucous membranes. The respiratory system is the major target of air pollutants and its major defense mechanism depends on the continuous activity of the cilia and the resulting constant transportation of mucous secretion. The present study was designed to evaluate the effects of formaldehyde on the ciliated epithelium through a relative large dose range around the threshold limit value adopted by the Brazilian legislation, namely 1.6 ppm (1.25 to 5 ppm). For this purpose, the isolated frog palate preparation was used as the target of toxic injury. Four groups of frog palates were exposed to diluted Ringer solution (control, N = 8) and formaldehyde diluted in Ringer solution at three different concentrations (1.25, 2.5 and 5.0 ppm, N = 10 for each group). Mucociliary clearance and ciliary beat frequency decreased significantly in contact with formaldehyde at the concentrations of 2.5 and 5.0 ppm after 60 min of exposure (P<0.05). We conclude that relatively low concentrations of formaldehyde, which is even below the Brazilian threshold limit value, are sufficient to cause short-term mucociliary impairment

Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium.

The increasing use of alcohol as an alternative fuel to gasoline or diesel can increase emission of formaldehyde, an organic gas that is irritant to the mucous membranes. The respiratory system is the major target of air pollutants and its major defense mechanism depends on the continuous activity of the cilia and the resulting constant transportation of mucous secretion. The present study was designed to evaluate the effects of formaldehyde on the ciliated epithelium through a relative large dose range around the threshold limit value adopted by the Brazilian legislation, namely 1.6 ppm (1.25 to 5 ppm). For this purpose, the isolated frog palate preparation was used as the target of toxic injury. Four groups of frog palates were exposed to diluted Ringer solution (control, N = 8) and formaldehyde diluted in Ringer solution at three different concentrations (1.25, 2.5 and 5.0 ppm, N = 10 for each group). Mucociliary clearance and ciliary beat frequency decreased significantly in contact with formaldehyde at the concentrations of 2.5 and 5.0 ppm after 60 min of exposure (P<0.05). We conclude that relatively low concentrations of formaldehyde, which is even below the Brazilian threshold limit value, are sufficient to cause short-term mucociliary impairment.

Simultaneous determination of ivabradine and its metabolites in human plasma by liquid chromatography--tandem mass spectrometry.

A rapid, selective, sensitive and reproducible liquid chromatographic method with tandem mass spectrometric detection has been developed and validated for the analysis of a new specific bradycardic agent, ivabradine (S 16257) and six potentially active metabolites in human plasma. Isolation of these compounds and of the internal standard was performed by an automated solid-phase extraction system using Oasis cartridges. Separation and detection of ivabradine and its metabolites were achieved using a C18 column and a MS-MS detector with a positive electrospray ionization source. Ivabradine and its metabolites gave a linear response ranging from 0.1 or 0.2 to 20 ng/ml and the limits of quantitation ranged from 0.1 to 0.2 ng/ml using a 0.5 ml plasma sample size. A complete validation demonstrated the method to be accurate, precise and specific for the simultaneous quantification of ivabradine and its metabolites in human plasma. The method was subsequently applied to the quantitative determination of ivabradine and its metabolites in human plasma samples from healthy volunteers participating in a clinical study to provide pharmacokinetic data.

Determination of melatonin in biological fluids in the presence of the melatonin agonist S 20098: comparison of immunological techniques and GC-MS methods.

Immunoassays were investigated for the determination of melatonin in biological samples in the presence of a naphthalenic structural analogue S 20098, which is currently under development as a melatonin agonist. The lack of specificity of commercially available antibodies in the presence of closely related molecules led us to develop an LC-RIA procedure with a quantification limit set at 15 pg/ml(-1). Because this technique was not sensitive enough and difficult to use on a routine basis, a more sensitive GC-MS technique was developed. This method involved automated solid-phase extraction (plasma) or liquid-liquid extraction (saliva), derivatization of the indolic moiety and GC separation with an automated switching device before MS detection. The method was validated over the range 1-100 pg/ml(-1), with a quantification limit set at 1 pg/ml(-1) in human plasma and saliva. Intra-assay and inter-assay precision and accuracy were within 16% for all concentrations investigated and each biological matrix. The stability of melatonin in plasma and saliva under various storage conditions was also determined. The specificity of the assay for the analysis of melatonin in the presence of S 20098 and its metabolises was demonstrated. The method was subsequently applied for the determination of endogenous melatonin concentrations in plasma and saliva samples from clinical studies performed with S 20098 to provide pharmacodynamic data.

Production and characterization of polyclonal anti-S 20499 antibodies: influence of the hapten structure on stereospecificity.

Immunoassays were studied as an alternative to HPLC methods for the stereoselective determination of a chiral drug, S 20499, a new anxiolytic compound that is chemically related to buspirone. The production of highly stereospecific polyclonal antibodies was sought following the construction of appropriately optimized hapten-protein conjugates. This process involved the selection of the structure and the length of the spacer arm used to couple S 20499 to the carrier protein as well as deciding on the location of the coupling site with respect to the chiral center. Two haptens were prepared: one a derivative resembling the original structure of S 20499, with the effective addition of a carboxylic acid group, and a second with the effective addition of a butanoic acid moiety that is supposed to favor stereorecognition. Six stereospecific polyclonal antisera were obtained in rabbits with two groups of antibody families defined in terms of specificity. Both approaches gave high levels of stereospecificity (cross-reactivity towards the optical antipode of S 20499 ranged from 4.1% to < 0.1%). Although it did not decrease the mean apparent affinity constant, the longer spacer improved antibody specificity by decreasing cross-reactions towards dealkylated S 20499 derivatives. Hence, the addition of a four carbon atom bridge should be a valuable tool for increasing antibody stereospecificity with no drawbacks in terms of specificity and affinity. It was also shown that long immunization periods appear to have no effect on the stereospecificity of the antibodies obtained.

Evaluation of a commercial test kit for rapid detection of Staphylococcus aureus in blood cultures.

The presence of Staphylococcus aureus in positive blood cultures could be rapidly confirmed by the use of a commercial test kit (Rapidec Staph; bioMérieux, France) that detects coagulase in the culture broth after 2 h of incubation. This kit detected all 35 Staphylococcus aureus strains from 117 blood cultures with gram-positive cocci growing in clusters. The sensitivity and the specificity of the technique were 100% and 98.8%, respectively. The Rapidec Staph kit appears to be a simple and reliable technique for the rapid detection of Staphylococcus aureus in blood cultures.

Determination of S 12024 enantiomers in human plasma by liquid chromatography after chiral pre-column derivatization.

S 12024-2 is a new drug in phase II development that possesses cognitive enhancing properties. As its molecular structure has a chiral centre, a stereoselective method for the analysis of both enantiomers in human plasma has been developed. The method involves pre-column derivatization of the amine moiety with a homochiral reagent (+)-1-(9-fluorenyl)ethyl chloroformate (FLEC), and chromatographic separation of the two diastereoisomers on an achiral reversed-phase cyanopropyl column, with fluorimetric detection (lambda ex = 260 nm; lambda em = 310 nm). A liquid-liquid extraction procedure with diethyl ether-dichloromethane (70:30, v/v) was used for sample preparation. This technique provides a linear response for both enantiomers over a concentration range of 10-500 ng ml-1 and the quantitation limit was set at 5 ng ml-1 in human plasma. Within-day and between-day precision and accuracy are within 9% limits for all concentrations assessed. This procedure was therefore used for determining both enantiomers in human plasma following oral administration of racemic S 12024-2 to elderly healthy subjects.