Thermoacclimatory changes in blood oxygen binding properties and gill secondary lamellar structure ofSalmo gairdneri

Summary The blood oxygen binding properties and gill secondary lamellar structure of rainbow trout acclimated to several temperatures were studied. The blood oxygen carrying capacity decreased as acclimation temperature increased from 2 to 15 °C; the decrease was probably caused by an increase in plasma volume. Also the blood oxygen affinity decreased as the acclimation temperature increased from 2 to 15 °C. This change had no effect on the oxygen loading in gills, since the efferent arterial oxygen tension was adequate for approximately 100% erythrocytic O₂ saturation at all acclimation temperatures, but facilitated the oxygen unloading in tissues. At the highest acclimation temperature (18 °C) the oxygen loading in gills was facilitated by the changes in the secondary lamellar structure; the proportion of erythrocytes in the secondary lamellar capillaries was higher than at the other acclimation temperatures (2 and 10 °C).     

Analysis of a 2,4,6-trichlorophenol-dehalogenating enrichment culture and isolation of the dehalogenating member Desulfitobacterium frappieri strain TCP-A

An anaerobic, 2,4,6-trichlorophenol ortho-dehalogenating mixed culture was enriched from sediment of the river Saale (Germany). Two isolated dechlorinating colonies (MK1 and MK2) consisted of rods of different lengths and thicknesses, indicating heterogeneity. Following subcultivation with thiosulfate as alternative electron acceptor and cocultivation with Clostridium celerecrescensT, the 2,4,6-trichlorophenol-dehalogenating bacterium Desulfitobacterium frappieri strain TCP-A was isolated and characterized regarding its taxonomic properties and the spectrum of chlorophenols that it dehalogenated. Four other bacterial strains were coenriched and identified as organisms with closest phylogenetic relatedness to the Clostridium type strains C. indolis, C. glycolicum, C. hydroxybenzoicum and C. sporosphaeroides (16S rDNA sequence identities of 99.5, 99.2, 94.4, and 93.5%, respectively). Amplified ribosomal DNA restriction analysis of the original dehalogenating cultures MK1 and MK2 (when not exposed to thiosulfate) confirmed the microbial heterogeneity and revealed the presence of two additional species related to the type strains of C. celerecrescens and Clostridium propionicum. Only one copy of the 16S rRNA genes of Desulfitobacterium frappieri in each of the clone libraries of MK1 and MK2 (containing 136 and 56 clones, respectively) was found by dot-blot hybridization, suggesting a relatively low number of the dehalogenating bacterium within the enrichment culture.     

Optimizing efficacy of quick parathyroid hormone determination in the operating theater

The usefulness of intraoperative parathyroid hormone (PTH) monitoring has been extensively documented in primary hyperparathyroidism (HPT), whereas few data have been published on its use in reoperations or in secondary and tertiary HPT. We report our initial experience with a rapid (12 min response) PTH immunochemiluminometric assay performed in the operating room during surgery in 12 patients with primary HPT, 16 end-stage renal disease patients with secondary HPT and five kidney transplanted subjects with tertiary HPT. Blood samples were taken at baseline, within 10 min after resection and subsequently at various intervals whenever needed. The mean PTH levels before and after parathyroidectomy were 230.5 pg/mL (range 69-842) and 47.3 pg/mL (range 5-184), respectively, in primary HPT, 855.0 pg/mL (416-1655) and 202.2 pg/mL (53-440) in secondary HPT, and 205.6 pg/mL (116-301) and 45.4 pg/mL (18-97) in tertiary HPT. All patients but one had a significant percentage decline from pre-excision values (mean 76.9%, 76.0%, and 76.1% in primary, secondary and tertiary HPT, respectively). While a reduction of more than 50% was observed in 30 out of 33 patients after the first intraoperative sampling, additional measurements were performed in 10 cases. On-site PTH monitoring with this user-friendly and reliable system has proved helpful in targeting PTH tests to give the surgeon a rapid and accurate assessment of the intervention. The development of optimal PTH sequence strategies with decision-focused analytical and clinical limits will improve the efficacy of "point-of-care" PTH assay and resource utilization.     

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea (American Fisheries Society Symposium 21). Edited by Gordon McDonald,John D. Fitzsimons and Dale C. Honeyfield

Reviews in Fish Biology and Fisheries -     

Systemic Treatment with Erythropoietin Protects the Neurovascular Unit in a Rat Model of Retinal Neurodegeneration

Rats expressing a transgenic polycystic kidney disease (PKD) gene develop photoreceptor degeneration and subsequent vasoregression, as well as activation of retinal microglia and macroglia. To target the whole neuroglialvascular unit, neuro- and vasoprotective Erythropoietin (EPO) was intraperitoneally injected into four –week old male heterozygous PKD rats three times a week at a dose of 256 IU/kg body weight. For comparison EPO-like peptide, lacking unwanted side effects of EPO treatment, was given five times a week at a dose of 10 µg/kg body weight. Matched EPO treated Sprague Dawley and water-injected PKD rats were held as controls. After four weeks of treatment the animals were sacrificed and analysis of the neurovascular morphology, glial cell activity and pAkt localization was performed. The number of endothelial cells and pericytes did not change after treatment with EPO or EPO-like peptide. There was a nonsignificant reduction of migrating pericytes by 23% and 49%, respectively. Formation of acellular capillaries was significantly reduced by 49% (p<0.001) or 40% (p<0.05). EPO-treatment protected against thinning of the central retina by 10% (p<0.05), a composite of an increase of the outer nuclear layer by 12% (p<0.01) and in the outer segments of photoreceptors by 26% (p<0.001). Quantification of cell nuclei revealed no difference. Microglial activity, shown by gene expression of CD74, decreased by 67% (p<0.01) after EPO and 36% (n.s.) after EPO-like peptide treatment. In conclusion, EPO safeguards the neuroglialvascular unit in a model of retinal neurodegeneration and secondary vasoregression. This finding strengthens EPO in its protective capability for the whole neuroglialvascular unit.     

Cold exposure increases branchial water–blood barrier thickness in the eel

Cold acclimation (5 v . 25° C) of freshwater eel, Anguilla anguilla induces a remodelling of gill fine structure. The increase in branchial water–blood barrier thickness may reflect an adaptive response appropriate for overwintering torpor.