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Naruepon Kampa DVM Ursula Wennstrom DVM Peter Lord BVSc FRCVS Robert Twardock DVM PhD Enn Maripuu BSc Per Eksell DVM PhD Sten-Olof Fredriksson BSc 《Veterinary radiology & ultrasound》2002,43(4):383-391
Determinations of different methods of measurement of uptake of 99mTc-DTPA using scintigraphy of glomerular filtration rate (GFR) were made from 29 studies on 10 healthy beagle dogs. GFR was measured by calculating the percentage dose uptake (integral method) and rate of uptake (slope method) of 99mTc-DTPA using manual kidney regions of interest (ROI) and automatic kidney and background ROIs at different time periods of the uptake phase. These results were compared using linear regression analysis to the GFR obtained from 99mTc-DTPA plasma clearance using multiple blood samples. The best correlation coefficient between percentage DTPA uptake and GFR by DTPA clearance (r = 0.84, P < 0.001) was derived from time intervals between 30s-120s with a perirenal background ROI at 1 or 2 pixels out from the kidney ROI using automatic kidney ROI at 20% threshold. With the slope method, the best correlation coefficient (r = 0.85, P < 0.001) was obtained from time intervals between 30s-peak with the background ROI at 2 pixels out from the kidney ROI using automatic ROI at 35% threshold. The offset was higher, and the correlation varied more with different ROIs and the method was unreliable at time intervals extending beyond the peak radioactivity. Manual kidney ROIs with automatic background ROIs had slightly lower correlations. With DTPA renography both integral and slope uptake method with automatic kidney and background ROIs are accurate methods to estimate the GFR, but that the integral method is much more stable to variations in ROI size and the duration of the uptake phase of the renogram. 相似文献
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Timo Kautza Frank Ellmer Cristina López-Fando Enn Leedu Wolfgang Köhn 《Archives of Agronomy and Soil Science》2013,59(5):513-520
Soil micro-arthropods play an important role in the nutrient cycle of agro-ecosystems and are considered to have a strong impact on microbial activity. The occurance of soil microarthropods was investigated in the International Organic Long-Term Field Experiment (IOSDV). The investigation took place in the experimental fields of Berlin/Germany, Madrid/Spain and Tartu/Estonia. Field plots "without organic fertisation", "farmyard manure" and "straw-beet-leaves-green manure" without mineral N-fertilisation and with 120kg/ha mineral N-fertilisation respectively have been investigated. Data shows that the effects of organic manure and mineral N-fertilisation are considerably influenced by specific site characteristics. The highest abundances were found in the experimental field of Madrid. In the two nothern sites soil microarthropods were found only in very low quantities. Data indicates that not only organic manure but also mineral N-fertilisation may influence the abundance of soil micro-arthropods positively. 相似文献
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Liina Talgre Enn Lauringson Hugo Roostalu Alar Astover Viacheslav Eremeev Are Selge 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):70-76
Abstract A field experiment was conducted in 2004–2006 to investigate the effect of green manure treatments on the yield of oats and spring barley. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, and organic matter driven into soil and their effect on cereal yield. The spring barley field had a total of 41.7–62.4 kg N ha?1 and 1.75–2.81 Mg C ha?1 added to the soil with straw, weed, and roots, depending on the level of fertilisation; with red clover, and both common and hybrid lucerne undersowing, with barley straw and roots, the values were 3.45–3.96 Mg C ha?1 and 139.9–184.9 kg N ha?1. Pure sowings of these three leguminous green manure crops had total applications of 3.37–4.14 Mg C ha?1 and 219.7–236.8 kg N ha?1. The mixed and pure sowing of bird's-foot trefoil provided considerably less nitrogen and carbon to the soil with the biomass than with the other leguminous crops. Application of biomass with a high C/N ratio reduced the yield of the succeeding spring cereals. Of the green manures, the most effective were red clover and both common and hybrid lucerne, either as undersowing or as pure sowing. Undersowings with barley significantly increased the N supply for the succeeding crop without yield loss of the main crop compared with the unfertilised variant. Compared with ploughing-in of green manure in autumn, spring ploughing gave a 0.2–0.57 Mg ha?1 larger grain yield. 相似文献
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Viia Lepane Kai Künnis-Beres Enn Kaup Bhupesh Sharma 《Journal of Soils and Sediments》2018,18(8):2715-2726
Purpose
This study focuses on the application of HPLC in dissolved organic matter (DOM) research in Antarctic environment together with nutrients and heterotrophic bacteria (HB) analyses. The specific aims were to investigate changes in DOM components characteristics and in nutrients in soil core from ground active layer and upper permafrost, to relate obtained data to active heterotrophic bacteria records after applying statistical data treatment methods, and to explore the potential impact of environment.Materials and methods
A single Antarctic 1.9-m deep soil core drilled at a site without human impact from Schirmacher Oasis, located 70° 46′ 02″ S and 11° 45′ 11″ E, was explored. The chromophoric DOM (CDOM) was characterized by soil water analysis using multi-wavelength HPLC. Total organic carbon and total nitrogen were determined by elemental analysis, the total phosphorus by inductively coupled plasma spectrometry. The vertical changes in those nutrients and their ratios were investigated. The microbiological analysis was accomplished through the determination of psychrotrophic and psychrophilic aerobic HB numbers by colony-forming units counting method, and by epifluorescence microscopy examination. Cluster analysis using the Ward method and principal component analysis was performed on the chromatographic and microbiology data to reveal similar layers in studied soil core.Results and discussion
In active soil layer, the CDOM was missing thus indicating rather active decomposition of organic material or organic debris by the local microbial community. In deep permafrost layers, the quantity of CDOM preserved in soil water increased. The content of total organic carbon in soil was low, between 0.05 and 0.2%, and decreased down the core. The vertical changes in nutrients (total N and P), the ratios C/N and C/P, followed total organic carbon profile suggesting similar sources. Microbiological analyses showed decreasing vertical concentrations of active HB. Statistical data treatment methods enabled clustering of soil core into three zones according to depth.Conclusions
The obtained results contribute to better understanding of organic carbon-related processes in an almost un-polluted Antarctic environment. The CDOM, macronutrients, C/N, C/P, and HB profile characteristics of the Antarctic soil core clearly demonstrate the effect of environment (active or permafrost soil layers). The study demonstrated that combining HPLC with multi-wavelength detection and microbial analyses with statistical data treatment is potentially a promising tool of investigating changes in Antarctic soil DOM and in soil waters generally.5.
Lord P Eriksson A Häggström J Järvinen AK Kvart C Hansson K Maripuu E Mäkelä O 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(6):824-829
Pulmonary transit time (PTT) normalized to heart rate (nPTT) is a measure of the pulmonary blood volume (PBV) to stroke volume ratio (PBV/SV). It is an index of cardiac performance. To determine the effect of compensated mitral regurgitation (CMR) and decompensated mitral regurgitation (DMR) caused by valvular endocardiosis on the index nPTT, we measured nPTT by first-pass radionuclide angiocardiography and ECG in 13 normal dogs, 18 dogs with CMR, and 13 dogs with DMR. PTT was measured as time between onset of appearance of activity at the pulmonary trunk and the left atrium. In the normal dogs, the relationship between PTT and mean R-R interval (mRR) was PTT = 4.08 x mRR + 0.15 (R2 = 0.71). Normal nPTT was 4.4 +/- 0.6 (SD) (range. 3.6-5.3). in CMR, 6.3 +/- 1.6 (SD) (range, 4.0-9.7). and in DMR, 11.9 +/- 3.4 (SD) (range, 8.0-18.8). The differences among all groups were significant. Heart rates were 110 +/- 22 bpm in normal dogs, 111 +/- 20 in dogs with CMR, and 144 +/- 18 in dogs with DMR (P < .001 for difference between DMR group and normal and CMR groups). Increased nPTT in CMR indicates preclinical heart pump dysfunction. Heart rate-normalized pulmonary transit times may be a useful index of heart function in mitral regurgitation. 相似文献
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Lech Szajdak DSc Paul Kuldkepp Enn Leedu Triin Teesalu Avo Toomsoo Raimo Kotildelli 《Archives of Agronomy and Soil Science》2013,59(2):127-137
Abstract This study was conducted to measure the concentrations of Ntotal, N-NH4 +, N-NO3 ?, total organic carbon, dissolved organic carbon, and indole-3-acetic acid (IAA) and also activity of nitrate reductase as well as activity of urease from Fragi-Stagnic Albeluvisols' organic matter in a field experiment (crop rotation: potato – spring wheat – spring barley). Samples were obtained from long-term field studies at Eerika near Tartu, Estonia, and from the forest Tiksoja. The experimental plots were under different regimes of organic and mineral fertilizers. The concentrations of Ntotal, indole-3-acetic acid, activity of urease and C/N ratios were generally the highest in the forest soil Tiksoja. Application of organic and mineral fertilizers increased the activity of both enzymes as well as the concentrations of indole-3-acetic acid in soils. The various fertilizer regimes influenced biochemical factors in soils as well as crop yields. The increase of crop yields was associated with the activity of both enzymes and the content of indole-3-acetic acid in soils. 相似文献
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