Determination of diazepam in aquatic samples by capillary liquid chromatography-electrospray tandem mass spectrometry.

In recent years growing attention has been paid toward the discharge, presence and potential adverse effects of pharmaceuticals in the environment. Using different existing analytical methods several studies have already identified a variety of drugs in waste-, surface- and drinking water. The monitoring of surface waters for drugs is of great importance because drugs are designed to be biological very active substances.

An ecologically relevant exposure assessment for a polluted river using an integrated multivariate PLS approach.

A case study is presented where an integrated, ecologically relevant exposure assessment is presented for a polluted lowland river. Using partial least squares regression of latent structures (PLS), an analysis of the impact of two effluents on physico-chemical water quality measures, macroinvertebrate and diatom communities, and in situ bioassay responses with four different test species are combined into an integrative exposure assessment. Bioassays focussed on growth and condition related endpoints, because they are key functional processes of organisms and populations.

In situ and laboratory bioassays to evaluate the impact of effluent discharges on receiving aquatic ecosystems.

Effluents are a main source of direct and often continuous input of pollutants into aquatic ecosystems with long-term implications on ecosystem functioning. Therefore, the study of the effects of effluent exposure on organisms, populations or communities within the framework of impact assessment has a high ecological relevance. The aim of this study was to assess the toxicological impact of two effluents, one household wastewater treatment effluent (Effluent 1) and one industrial effluent (Effluent 2), on the receiving aquatic ecosystem using two test species under both in situ and laboratory conditions.

Compressibility and specific heats of heavier condensed rare gases near the liquid-vapor critical point.

This study concerns the way to describe some physical properties of simple liquids by using the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy. It constructively analyzes the recent contribution of Sarkisov [G. N.

Environmentally low-temperature kinetic and thermodynamic study of lactate dehydrogenase from Atlantic cod (G. morhua) using a 96-well microplate technique.

Analyses of temperature-dependent kinetic parameters in enzymes extracted from tissues of ectothermic animals are usually carried out within the range of physiological temperatures (0-40 degrees C). However, multisample spectrophotometers (so-called microplate readers) with efficient wide-range temperature control (including cooling) have previously been unavailable. This limits the statistical quality of the measurements.

The population genetic structure of Littorina littorea (Mollusca: Gastropoda) along a pollution gradient in the Scheldt estuary (The Netherlands) using RAPD analysis.

The population genetic structure of the periwinkle Littorina littorea was analysed using random amplified polymorphic DNA (RAPD). Three primers, coding for six putative polymorphic loci were surveyed to infer the genetic structure of seven populations located along the heavily polluted Western (i.e.

Analysis of an Arabidopsis thaliana protein family, structurally related to cytochromes b561 and potentially involved in catecholamine biochemistry in plants.

Cytochromes b561 (cyts b561) constitute a family of eukaryotic membrane proteins, catalysing ascorbate (Asc)-mediated trans-membrane electron transport, and hence likely involved in Asc regeneration. A class of proteins (DoH-CB) has been identified in plants and animals, containing the cyt b561 electron-transport domain (CB), combined with the catecholamine-binding regulatory domain of dopamine-beta-hydroxylase (DoH). A mammalian DoH-CB protein was previously reported to function as a cell-derived growth factor receptor (SDR2).

Caged midge larvae (Chironomus riparius) for the assessment of metal bioaccumulation from sediments in situ.

First-stage larvae of the midge Chironomus riparius were exposed in small enclosures at 19 sites located in three different river basins in Flanders (Belgium). Sediments were sampled and sieved at 200 microm at all exposure sites. A layer of approximately 2 cm of sediment was placed in each cage and 100 midge larvae were added.

Cellular energy allocation in zebra mussels exposed along a pollution gradient: linking cellular effects to higher levels of biological organization.

Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult.

Topology, connectivity, and electronic structure of C and B cages and the corresponding nanotubes.

After a brief discussion of the structural trends which appear with an increasing number of atoms in B cages, a one-to one correspondence between the connectivity of B cages and C cage structures will be proposed. The electronic level spectra of both systems from Hartree-Fock calculations is given and discussed. The relation of curvature introduced into an originally planar graphitic fragment to pentagonal "defects" such as are present in buckminsterfullerene is also briefly treated.

Induction of the avian coelom with associated vitelline blood circulation by Rauber's sickle derived junctional endoblast and its fundamental role in heart formation.

In histological sections through chicken blastoderms of different ages we describe the temporospatial relationship between junctional endoblast, the formation of blood islands (appearing first from a peripherally migrating mesoblastic blastema), and the formation of coelomic vesicles developing later in/and from a more superficially extending mesoblastic blastema (coelomic mesoblast). After unilateral removal of the Rauber's sickle-derived junctional endoblast in early streak blastoderms (stage 2-4; Vakaet [1970] Arch Biol 81:387-426) and culture to stage 11 (Hamburger and Hamilton [1951] J Morphol 88:49-92), we observed that the early formation of the coelomic cavity was locally or totally disturbed in the operated area. Besides the simultaneous absence of blood islands, the coelomic vesicles did not form normally.

Is atomic resolution transmission electron microscopy able to resolve and refine amorphous structures?

Atomic resolution transmission electron microscopy, even with an aberration free microscope, is only able to resolve and refine amorphous structures at the atomic level for very small foil thicknesses. Then, a precision of the order of 0.01 A is possible, but this may require long recording times, especially for light atoms.

Use-dependent blockade of cardiac pacemaker current (If) by cilobradine and zatebradine.

The action of the bradycardiac agents, cilobradine (DK-AH269) and zatebradine (UL-FS49), on the cardiac pacemaker current (If) was investigated on short Purkinje fibres from sheep hearts, using the two-microelectrode voltage-clamp technique, and on isolated rabbit sino-atrial cells with the patch clamp technique. These drugs reduce dose dependently the amplitude of the If, without modifying either the voltage dependence or the kinetics of channel activation. When voltage-clamp pulse trains were applied, cilobradine induced a use-dependent blockade of If that was stronger and faster than that with zatebradine.

Chronic and acute stress as predictors of relapse in primary breast cancer patients.

In this paper we present data on predictors of early relapse (at three and a half years post-surgery) in 44 patients with primary breast carcinoma. We expected that the degree to which receiving the diagnosis of malignancy would act as an acute stressor would allow a prediction of early relapse. Acute stress is measured by means of changes in psychological, neurochemical and immunological indicators of stress before and after the communication of the diagnosis.

Host nutritive quality and host plant choice in two grass miners: primary roles for primary compounds?

The relationship between host plant choice and plant nutritional quality was investigated in two oligophagous grass miners Chromatomyia milii and C. nigra (Diptera, Agromyzidae). We tested whether host choice is determined by chemically mediated host suitability for offspring performance and/or adult performance.

Simultaneous high-throughput determination of clenbuterol, ambroxol and bromhexine in pharmaceutical formulations by HPLC with potentiometric detection.

Potentiometric detection of clenbuterol, ambroxol and bromhexine in marketed pharmaceuticals was described in six isocratic HPLC systems. The podant- and macrocyclic-type neutral ionophores, N,N,N',N'-tetracyclohexyl-oxybis(o-phenyleneoxy)diacetamide (TOPA) and hexakis(2,3,6-tri-O-octyl)-alpha-cyclodextrin (OCD), were applied in poly(vinyl)chloride (PVC)-based liquid membrane electrodes. Both types of neutral ionophores improve the sensitivity for all mentioned drugs when compared with a tetrakis(p-chlorophenyl)borate (BOR)-based electrode as well as with single wavelength UV detection.

Metal concentrations in water, sediment and gudgeon (Gobio gobio) from a pollution gradient: relationship with fish condition factor.

This study assesses the applicability of a sentinel fish species as a biomonitor of metal pollution. Gudgeon (Gobio gobio) were collected from 14 sites in metal polluted lowland rivers in Flanders, including a clear Cd and Zn pollution gradient. Fish tissues were analysed for Cd, Cr, Cu, Ni, Pb and Zn.

Accumulation of 137Cs by larvae of the midge Chironomus riparius from sediment effect of potassium.

We studied the effect of potassium on the uptake of radiocesium from sediment by larvae of the midge Chironomus riparius. Sediment ingestion rate was determined for one week. After 24 h the gut content remained constant, indicating that equilibrium was reached between sediment ingestion and sediment elimination.

Metallothionein concentrations in natural populations of gudgeon (Gobio gobio): relationship with metal concentrations in tissues and environment.

A field monitoring campaign investigating the suitability of (Cd, Zn)-metallothionein concentrations (MTs) in different tissues of the gudgeon as a biomarker for metal contamination in the aquatic environment was conducted. Gudgeons were captured at 10 sampling sites on a river system in Flanders (Belgium). Nine sampling sites were situated along a Cd and Zn gradient with a nearby tributary as the reference site.

Quantification of neuroepithelial bodies and their innervation in fawn-hooded and Wistar rat lungs.

The Fawn-Hooded rat (FHR), a model for primary pulmonary hypertension, shows an unexplained hypersensitivity to airway hypoxia. Because pulmonary neuroepithelial bodies (NEBs) appear to express a functional oxygen-sensing mechanism and an extensive sensory innervation, possible changes in this system should be taken into consideration. In the present study a comparative analysis of NEBs and their selective innervation was performed in FHRs and Wistar control rats.

Thermal physiology of the common eelpout (Zoarces viviparus).

We investigated the temperature dependence of some physiological parameters of common eelpout (Zoarces viviparus) from different locations (North Sea, Baltic Sea and Norwegian Sea) on acclimation temperature (3 degrees C and 12 degrees C) and acute temperature variation. The lethal limit of 12 degrees C-acclimated eelpout was determined as the critical thermal maximum [loss of equilibrium (LE) and onset of muscular spasms (OS)] and it was found to be 26.6 degrees C for LE and 28.

Effect of intestinal inflammation on capsaicin-sensitive afferents in the ileum of Schistosoma mansoni-infected mice.

In the present study, the effect of intestinal schistosomiasis on the extrinsic sensory innervation of the murine ileum was investigated. Immunocytochemical techniques to localize calcitonin gene-related peptide (CGRP), substance P (SP), and vanilloid receptor 1 (VR1) were combined with retrograde tracing techniques and capsaicin treatment. Neurochemical characterization of extrinsic primary afferent neurons (EPANs) in normal and capsaicin-treated mice, revealed that CGRP and VR1, but not SP, were expressed in extrinsic afferents.

Effect of cortisol treatment and/or sublethal copper exposure on copper uptake and heat shock protein levels in common carp, Cyprinus carpio.

This study compared the effects of increased endogenous cortisol levels and/or sublethal Cu exposure on Cu accumulation and stress protein levels (HSP70) in the freshwater common carp, Cyprinus carpio. Fish were exposed to either increased levels of endogenous cortisol (200 ng/ml) or sublethal Cu concentrations (1.9 microM, approximately 20% of the acute 96-h median lethal concentration [LC50]) alone or were pretreated by elevating plasma cortisol levels prior to Cu exposure to evaluate whether interactions between both treatments occurred.