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1.
Filtration rate capacities in 6 species of European freshwater bivalves 总被引:12,自引:0,他引:12
Summary Filtration rate capacities in undisturbed freshwater bivalves were determined by means of two different methods (indirect clearance and suction methods) in Anodonta anatina (L.), Unio tumidus Philipsson, Unio pictorum (L.), Unio crassus Philipsson, Dreissena polymorpha (Pallas) and Sphaerium corneum (L.). In A. anatina, D. polymorpha, and S. corneum the filtration rate (FR, 1 h-1) at 19–20°C as a function of dry tissue weight (DW, g) or ash-free dry weight (AFDW, g) could be expressed by the equations: 1.10 DW0.78, 6.82 DW0.88, and 2.14 AFDW0.92, respectively. In U. tumidus, U. pictorum, and U. crassus filtration rates were comparable with those of A. anatina. In D. polymorpha the b value of the corresponding regression of gill area on dry weight was 0.87. The rates of water transport in freshwater bivalves are 2–8 times lower than in marine bivalves of comparable size. A corresponding difference in the filtration rate per gill area unit is found. The measured filtration rates in undisturbed bivalves are substantially higher (at least 4 times) than previously reported. This indicates that the impact of bivalve water processing on freshwater ecosystems is greater than hitherto suggested. 相似文献
2.
Tina Pallesen Annette Vangsted Lars Drivsholm Henrik Clausen Jesper Zeuthen Håkan Wallin 《Glycoconjugate journal》1992,9(6):331-335
We here report an enzyme linked immunosorbent assay (ELISA) and a scintillation proximity assay (SPA) for detection of the ganglioside FucGM1 in sera from small cell lung cancer (SCLC) patients. The SPA was more sensitive and reproducible than the ELISA. In this assay, monoclonal antibodies specific for FucGM1 were bound to SPA particles and incubated with labelled FucGM1 and 100 µl test-serum overnight, and counted in a -counter. The sensitivity was 0.2 ng. Seven out of twenty sera from SCLC patients were positive, whereas none of twenty sera from healthy individuals were positive for FucGM1. The SPA was more sensitive than the previously reported HPTLC as well as a direct ELISA.Abbreviations MAb
monoclonal antibody
- SPA
scintillation proximity assay
- HPTLC
high performance thin layer chromatography
- SCLC
small cell lung cancer
- FucGM1
Fuc1-2Gal1-3GalNAc1-4(NeuAc2-3)-Gal1-4Glc1-1Cer
- ELISA
enzyme linked immunosorbent assay
- FCS
foetal calf serum
- PBS
phosphate buffered saline 相似文献
3.
Net hepatic Ca2+ efflux, K+ uptake and glycogen breakdown in response to the alpha 1-adrenergic agonist phenylephrine were studied. Rat livers were perfused with CO2/bicarbonate-buffered solutions containing 10 microM Ca2+ and different amounts of Mg2+. K+-free medium and/or ouabain were used to block (Na+ + K+)-ATPase-dependent K+ uptake. In some experiments a sharp increase in extracellular Ca2+ concentrations was produced by infusing CaCl2 into the medium entering the liver. Perfusion with K+-free medium and ouabain enhanced the phenylephrine-induced Ca2+ efflux and diminished the glycogenolytic response, indicating a dissociation of Ca2+ release and glycogenolysis. Exogenous Ca2+ had practically no effect if livers were perfused with regular medium containing 1.2 mM Mg2+. In the presence of phenylephrine and if extracellular Mg2+ concentrations were lowered by omitting Mg2+ from the medium or by preperfusion with EGTA, exogenous Ca2+ was glycogenolytically effective and also produced a transient K+ uptake. Increased extracellular concentrations of Mg2+ inhibited the effects of exogenous Ca2+. In the presence of phenylephrine, higher concentrations of Mg2+ were needed than in the absence of alpha 1-adrenergic agonist to achieve a similar degree of inhibition. In one respect ouabain effects were comparable to those of phenylephrine: the glycoside also increased the metabolic response to exogenous Ca2+ and diminished the sensitivity towards Mg2+. Phenylephrine and ouabain may both enhance the permeability of plasma membranes for Ca2+. 相似文献
4.
A highly sensitive enzymatic assay for diadenosine 5′,5?-P1,P3-triphosphate (Ap3A) has been established on the basis of the coupled luminescence assay for diadenosine 5′,5?-P1,P3-tetraphosphate (A. Ogilvie (1981)Anal. Biochem.115, 302–307). Snake venom phosphodiesterase splits Ap3A into AMP plus ADP which can be measured in a luminescence reaction containing pyruvate kinase, phosphoenolpyruvate and luciferin-luciferase. The procedure is linear with Ap3A levels ranging from 0.1 to 2 pmol. The assay has been used to measure Ap3A in various eukaryotic cells after ion-exchange chromatography and high-performance liquid chromatography of acidic extracts of the cells. The level of diadenosine triphosphate was higher in all instances than the level of diadenosine tetraphosphate. When growing in the abdominal cavity of mice, Ehrlich ascites tumor cells contained high amounts of Ap3A (), allowing direct optical determination in the HPLC chromatography. The quantitative measurement of Ap3A with the luminescence assay gave identical results. Ap3A extracted from Ehrlich cells was also chromatographed with authentic nucleotide in two thin-layer systems providing additional proof for the existence of Ap3A in biological material. 相似文献
5.
Desmethylimipramine Enhances the Release of Endogenous GABA and Other Neuro trans mitter Amino Acids from the Rat Thalamus 总被引:2,自引:0,他引:2
The influence of desmethylimipramine (DMI) on the release of endogenous gamma-aminobutyric acid (GABA) and some other amino acids from the rat thalamus was studied with a push-pull perfusion technique. Following HPLC the amino acids were fluorimetrically estimated. Added to the perfusion medium at a concentration of 10 mumol L-1, DMI caused a 5- to 10-fold increase in the release of GABA. Similar effects were found with imipramine, trimeprimine, haloperidol, and propranolol. The elevation of GABA release induced by DMI was Ca dependent. The release of aspartate and glutamate was also increased by DMI, but in contrast to K ions, DMI did not reduce the thalamic output of glutamine. 相似文献
6.
7.
Zusammenfassung 19 Patienten, die nach einer Nierentransplantation mit Imuran behandelt wurden, wiesen eine erhöhte Anzahl Chromosomenabnormitäten im Vergleich zu 30 gesunden Kontrollpersonen der gleichen Altersklasse auf. Keine signifikant erhöhte Anzahl an Chromosomenabnormitäten fand sich jedoch bei 7 Patienten, die vor und unter der Imuran-behandlung untersucht wurden. Es wird vermutet, daß die Chromosomenabnormitäten bei den 19 mit Imuran behandelten Patienten wahrscheinlich nicht durch Imuran, sondern durch die Urämie entstanden sind.
Summary 19 patients treated with Imuran after a renal transplantation showed a high frequency of chromosome abnormalities, compared with 30 healthy control persons in the same age range. No significantly higher frequency of chromosome abnormalities was, however, found in 7 patients examined before and during treatment with Imuran. It is suggested that the chromosome abnormalities found in the 19 patients treated with Imuran were probably not due to Imuran but to Uremia.相似文献
8.
The relationship between the source strength and the “manifest vector” in the Einthoven Triangle is derived for a line and
a point dipole source and confirmed experimentally. The result permits the interpretation of the standard ECG leads in absolute
terms and corrected for body size. The manifest vector is shown to be approximately
times what it would be in an otherwise similar circular slab which circumscribes the triangle. 相似文献
9.
10.
Flemming Jessen Bruce D. Cherksey Thomas Zeuthen Else K. Hoffmann 《The Journal of membrane biology》1989,108(2):139-151
Summary Furosemide-binding proteins were isolated from cholate-solubilized membranes of Ehrlich ascites tumor cells by affinity chromatography, using furosemide as ligand. Solubilized proteins retarded by the affinity material were eluted by furosemide. In reducing and denaturing gels, the major proteins eluted by furosemide were 100 and 45 kDa. In nonreducing, nondenaturing gels, homodimers of both polypeptides were found, whereas no oligomeric proteins containing both polypeptides were seen. It is concluded that the furosemide gel binds two distinct dimeric proteins. The isolated proteins were reconstituted into phospholipid vesicles and the K+ transport activity of these vesicles was assayed by measurement of86Rb+ uptake against a large opposing K+ gradient. The reconstituted system was found to contain a K+ transporting protein, which is sensitive to Ba2+ like the K+ channel previously demonstrated to be activated in intact cells after cell swelling. 相似文献