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Enantiomeric selectivity in the environmental degradation of dichlorprop as determined by high performance capillary electrophoresis.
1996
Garrison A.W. | Schmitt P. | Martens D. | Kettrup A.
Pharmacokinetics of Tityus serrulatus scorpion venom determined by enzyme-linked immunosorbent assay in the rat
1996
Santana, G.C. | Freire, A.C.T. | Ferreira, A.P.L. | Chaves-Olortegui, C. | Diniz, C.R. | Freire-Maia, L.
Experiments were performed in two groups of anaesthetized rats to study the genesis of pulmonary oedema and to determine the pharmacokinetic parameters following a subcutaneous (s.c.) injection of Tityus serrulatus scorpion venom. In group 1, the rats were anaesthetized with pentobarbital (4 mg/100 g, i.p.); the s.c. injection of scorpion venom at the dose of 50 micrograms/100 g did not induce arterial hypertension, but unilateral pulmonary oedema was observed in three of six rats. The injection of a higher dose of venom (200 micrograms/100 g, N = 6) induced arterial hypertension and bilateral (N = 3) or unilateral (N = 1) pulmonary oedema. These data indicate that it is possible to evoke unilateral pulmonary oedema without previous arterial hypertension induced by the venom. For the study of pharmacokinetic parameters a second group of six rats was anaesthetized with urethane (140 mg/100 g, i.p.) and the venom injected at a dose of 200 micrograms/100 g, s.c. The plasma concentrations of venom were determined by enzyme-linked immunosorbent assay, at times 0, 5, 30, 60, 180, 360, and 720 min after venom injection. A biphasic curve was obtained with an ascending phase followed by a descending phase. The maximum plasma scorpion venom concentration was reached at 60 min. The pharmacokinetic parameters showed a fast absorption rate (K(a)= 0.058 min-1), a fast and high distribution of venom to tissues (t1/2 alpha = 31.50 min and V(d)area = 6800.47 ml.kg-1, respectively), a great affinity of the venom for the tissues (K(CT) = 0.056 min-1 and K(TC) = 0.002 min-1) and a slow elimination half-life (t1/2 beta = 173.25 min).
Afficher plus [+] Moins [-]Pharmacokinetics of Tityus serrulatus scorpion venom determined by enzyme-linked immunosorbent assay in the rat
1996
Santana, G.C. | Freire, A.C.T. | Ferreira, A.P.L. | Chavez-Olortegui, C. | Diniz, C.R. | Freire-Maia, L. (Departamento de Farmacologia, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, C. Postal 486, Belo Horizonte, MG (Brazil))
Incorporation of S into soil organic matter in the field as determined by the natural abundance of stable S isotopes
1996
Eriksen, J.
In agricultural systems with low S inputs, soil organic matter is a major source of S and the transformations between organic and inorganic S pools are important for the supply of S to plants. This study was conducted to determine the effect of S fertilizer on the size and activity of organic S pools. For 5 years S fertilizer with a known composition of stable S isotopes was applied to a rotation on a loamy soil and a coarse sandy soil at rates higher than the plant demand. Total organic S in soil organic matter was not affected by sulphur application, but a small increase occurred in the sulphate ester fractions (P<0.05). Inorganic sulphate concentrations in the soil reflected the S application in the year of sampling, whereas S applied in earlier years was not recognized. Organic matter below the plough layer in both soils was enriched with S, possibly as a result or organic matter leaching or an increased clay content in the subsoils. At 0-20 cm, the C:S ratio in organic matter was cat 100 for both soils, decreasing to 73 and 46 at 60-80 cm for the coarse sandy soil and the loamy soils, respectively. In both soils, isotope data showed that cat 30% of organic-bonded S at 0-20 cm originated from fertilizer S applied during the last 5 years, irrespective of the S application rate. At 20-40 cm the rate of incorporations was lower and at 40-60 cm no incorporation of fertilizer S into organic matter was recognized. The fertilizer application did not induce net changes in the total organic S fraction, but isotope data indicated that a considerable part of the organic S pool was involved in S cycling in the field.
Afficher plus [+] Moins [-]Correlation between the number of anaerobic bacteria in the sediment determined by MPN method and organics of the overlying water in the Jungnang-cheon
1996
Kim, B.H. | Lim, S.K. (Korea Institute of Science and Technology, Seoul (Korea Republic). Environmental Research Center) | Park, C.H. (Seokyung University, Seoul (Korea Republic). Department of Biological Engineering) | Choi, Y.H. (Jungnang Sewage Treatment Plant, Seoul (Korea Republic). Department of Water Analysis)
Diel feeding patterns and daily ration of cyprinid species in the wild determined using an iterative method, MAXIMS
1996
Silva, S.S. de | Amarasinghe, U.S. | Wijegoonawardena, N.D.N.S. (School of Aquatic Science and Natural Resources Management, Deakin University, P.O. Box 423, Warrnambool, Victoria 3280 (Australia))
Diel feeding patterns and daily ration of cyprinid species in the wild determined using an iterative method, MAXIMS Texte intégral
1996
de Silva, S.S. | Amarasinghe, U.S. | Wijegoonawardena, D.N.S.
Diel feeding patterns and daily food rations of five cyprinids Amblypharyngodon melettinus, Barbus chola, B. dorsalis, B. filamentosus and Rasbora daniconius in two Sri Lankan reservoirs were studied based on diel surveys using an iterative method, MAXIMS. A. melettinus and B. chola had single peaks of feeding whereas diel feeding patterns with two peaks occurred in the other three species. Daily food rations varied seasonally and with size of fish. The iterative technique used is reliably applicable for quantifying daily rations, and provides a means of linking trophic levels in natural populations of fish.
Afficher plus [+] Moins [-]Culicoides (Diptera: Ceratopogonidae) associated with livestock in the Onderstepoort area, Gauteng, South Africa as determined by light-trap collections
1996
Venter, G.J. | Meiswinkel, R. | Nevill, E.M. (Agricultural Research Council, Onderstepoort (South Africa). Onderstepoort Veterinary Inst.) | Edwardes, M.
Culicoides (Diptera: Ceratopogonidae) associated with livestock in the Onderstepoort area, Gauteng, South Africa as determined by light-trap collections Texte intégral
1996
In 54 light-trap collections made at 28 sites in the Onderstepoort area a total of 178 941 Culicoides midges of 35 species was collected in March 1988; the survey was repeated at 26 sites in September and yielded 19 518 Culicoides of 24 species. The number of Culicoides species collected totalled 38. C. imicola was the most abundant species at 27 of the 28 sites sampled, and accounted for 88% and 67% of all midges collected in the two months respectively. This study not only confirms that C. imicola is widespread and abundant in the greater Onderstepoort area, but also that its numbers correlate positively with the historical prevalence of African horse sickness (AHS) and bluetongue (BT) locally. The high numbers of C. imicola make Onderstepoort the ideal site for the study of its laboratory vector capacity. The relatively low numbers of Culicoides spp. other than C. imicola in the Onderstepoort area, will severely limit studies on their roles in the transmission of arboviruses. The origin of the blood-meals of 1 338 engorged Culicoides belonging to 13 species was determined by means of a cross-over electrophoresis precipitin test; C. imicola fed on cattle, horses, sheep and pigs. Four other Culicoides species showed a similarly wide host range.
Afficher plus [+] Moins [-]Food source of intertidal nematodes in the Bay of Marennes-Oleron (France), as determined by dual stable isotope analysis Texte intégral
1996
Riera, P | Richard, P | Gremare, A | Blanchard, G
Nematodes living on an intertidal mudflat of the Marennes-Oleron Bay (France) were assayed for delta(13)C and delta(15)N ratios together with their potential food resources between July 1992 and May 1993. Results suggest that nematodes do not exploit all the components of the sedimented organic matter (SOM) pool at the same rate. Furthermore, based on coefficients of average trophic enrichment found in the literature for both C and N, the enrichment of nematodes in C-13 and their depletion in N-15 relative to SOM suggest that microphytobenthos constitutes their main food source in this particular environment.
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