Electrophysiological characterization of electrolyte and nutrient transport across the small intestine in horses

The aim of this study was to characterize the transport mechanisms of electrolytes and nutrients across the jejunum of nine healthy horses electrophysiologically. The stripped mucosa was mounted in Ussing chambers and tissue conductances (G_t) and short circuit currents (I_sc) were continuously monitored. After blocking the sodium and potassium channels with amiloride, tetraethylammonium chloride (TEA) and barium, chloride secretion was stimulated by carbachol and forskolin. Subsequently, chloride channels were inhibited by 4,4′‐diisothiocyanato‐stilbene‐2,2′‐disulfonic acid, 5‐nitro‐2‐(3‐phenylpropylamino)benzoic acid, CFTR_inh‐172, N‐(2‐naphtalenyl)‐(3.5‐dibromo‐2.4‐dihydroxyphenyl)methylene glycine hydrazide (GlyH‐101) and glibenclamide and their dose–response effect was investigated. The response to glucose, l ‐alanine and glycyl‐l ‐glutamine was determined at two different mucosal pH values (pH 7.4 and 5.4 respectively). Mean basal I_sc was ?0.47 ± 0.31 μEq/cm²h and mean G_t was 22.17 ± 1.78 mS/cm². Amiloride and TEA did not alter the baseline I_sc. Barium, carbachol and forskolin significantly increased I_sc. Irrespective of the dose, none of the chloride inhibitors changed I_sc. All nutrients induced a significant increase in I_sc with the increase being significantly higher at pH 7.4 than at pH 5.4. In conclusion, there is evidence that chloride secretion in horses may be different from respective transport mechanisms in other species. The glucose absorption is suggestive of a sodium‐dependent glucose cotransporter 1. However, a decrease in luminal pH did not stimulate current response to peptides as shown for other mammals.     

Possibilities for computer tomography of the equine head based on two cases with a fracture of the base of the skull]

For the past 2 years computed tomography is used at the Veterinary School, University of Zürich. This new imaging modality enables the detection of abnormalities occurring in small and large animals which were previously not visible with imaging techniques. Subjects of this study were a foal and a small pony, both with suspected head trauma. Routine radiography could not explain any of the neurological deficiencies. In the first case a basilar skull fracture along with a focal brain hemorrhage was detected, in the second case multiple basilar skull fractures were seen. The computed tomographic examination after intravenous injection of an iodine-containing contrast medium also revealed epidural hemorrhage. These two cases demonstrate the diagnostic use of computed tomography as an extremely valuable asset when diagnosing head trauma in horses.     

Newcomers in the Baltic Sea: an attempt to trace the origins and whereabouts of thicklip grey mullet <Emphasis Type="Italic">Chelon labrosus</Emphasis>

In recent years, thicklip grey mullet Chelon labrosus has shown increasing expansion of its native habitats in the north-eastern Atlantic into northerly adjacent areas including the North Sea and the brackish Baltic Sea. Despite the regular annual and seasonal occurrence of C. labrosus in the western Baltic during the warm months, nothing is known of the origin or whereabouts of the mullet during the cold season. As different possible migration scenarios can be considered, we performed otolith microchemistry analyses on specimens from the western Baltic Sea to identify the origin of this nonindigenous species. Comparison with North Sea samples revealed common habitat preferences and underlined the highly euryhaline nature of C. labrosus in different recently occupied habitats. Occasional fluctuations of Sr/Ca ratio along the growth axis suggest periodical migration between waters of different salinities but did not reveal distinct migration pathways.     

Fulvic acid composition in degraded fenlands

Fulvic acids (FAs) from topsoil and ground water solutions were investigated to discover effects of land use and peat degradation on their molecular chemical composition and thermal properties. The FAs were extracted from three Gleysols under arable land, intensive and extensive grassland, and from three Histosols under alder forest, extensive grassland, and a natural succession in a long‐term (> 200 years) cultivated fen area. Functional groups and molecular subunits of the FAs were investigated by ¹³C Nuclear Magnetic Resonance (¹³C NMR) spectroscopy. Thermal properties and structural molecular subunits were investigated by off‐line pyrolysis, and Pyrolysis‐Field Ionization Mass Spectrometry (Py‐FIMS). The ¹³C NMR spectra showed that the FAs from topsoil solutions had smaller proportions of alkyl C (mean: —8 %) and more aromatic C (mean: + 6 %) than FAs from ground water. This clear differentiation of dissolved FAs in the soil profiles is consistent with Py‐FIMS data which have shown enrichments of lipids in ground water FAs. Furthermore, Py‐FIMS revealed that the FAs from topsoils were richer in phenols + lignin monomers, carbohydrates, as well as mostly aromatic N‐containing compounds. These molecular subunits of FAs, relatively enriched in topsoil, were also the main indicators of land use and peat degradation. For topsoil solutions, the proportions of phenols + lignin monomers and carbohydrates increased stepwise with peat degradation in Gleysols and Histosols. Correspondingly, the thermal properties indicated the incorporation of these compounds into FAs by chemical bonds of larger thermal stability. Statistical evaluation by principal component analysis of Py‐FIMS clearly supported the differentiation of FAs according to the origin from topsoils and ground water, different soil types, and land use and peat degradation. Hence, it is concluded that water soluble FAs can be utilized as objective ecological indicators for soil effects on adjacent ground and surface waters.