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  • Articles  (240)
  • kinetics
  • nitrogen
  • resistance
  • Springer  (240)
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  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (177)
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  • Articles  (240)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 26 (1987), S. 125-137 
    ISSN: 1436-6215
    Keywords: vitamin C ; functions ; kinetics ; pool ; saturation ; requirements ; RDA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die Bedeutung von Vitamin C für den menschlichen Organismus wird aus den wichtigen Funktionen ersichtlich, an denen das Vitamin beteiligt ist, wie zum Beispiel Kollagen- und Karnitinsynthesen. In neuerer Zeit entdeckt wurde seine Rolle bei der Noradrenalinsynthese, der Inaktivierung von freien Radikalen sowie der Verhinderung der Nitrosaminbildung. Die Vielfalt dieser Vitamin-C-abhängigen Funktionen läßt erkennen, daß die Bedarfsfestsetzung für Vitamin C nicht nur die Verhütung der Mangelkrankheit Skorbut anvisieren, sondern auch berücksichtigen sollte, daß alle diese Funktionen jederzeit genügend Vitamin C zur Verfügung haben müßten, um optimal reagieren zu können. Das Konzept der Gewebesättigung kommt diesem Ziel am nächsten. Studien mit einem kinetischen Modell haben ergeben, daß eine Sättigung mit täglicher Einnahme von 100 mg Vitamin C bei Nichtrauchern und von 140 mg bei Rauchern eintritt, Mengen, die als optimale Werte gelten können. Bei verschiedenen Krankheiten dürfte der Bedarf höher sein; die genauen Mengen müssen jedoch erst noch ermittelt werden.
    Notes: Summary The importance of vitamin C is reflected in its multifunctional roles which include participation in collagen and carnitine syntheses, promotion of iron absorption and the more recently discovered participation in noradrenaline synthesis, inactivation of free radical chain reactions, prevention of N-nitroso compound formation and more. Given the many extra-antiscorbutic functions of the vitamin, the Recommended Dietary Allowances (RDA) should not just prevent deficiency disease but should aim at providing sufficient amounts for all vitamin C-dependent functions to operate at full capacity. The concept of vitamin C tissue saturation is best able to meet this demand. The use of kinetic models has shown that the body pool is saturated with a daily intake of 100 mg vitamin C in non-smokers and 140 mg in smokers, amounts that may be regarded as optimal RDA values. Certain disease states may be accompanied by still higher vitamin C requirements but the exact amounts are not yet known.
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  • 2
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    Springer
    Cellular and molecular life sciences 40 (1984), S. 1311-1316 
    ISSN: 1420-9071
    Keywords: Malaria ; Plasmodia ; antimalarial drugs ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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  • 3
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    Mycopathologia 107 (1989), S. 51-55 
    ISSN: 1573-0832
    Keywords: Torulopsis glabrata ; ketoconazole ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The majority of clinical isolates of T. glabrata has been shown highly sensitive to ketoconazole, when tested with an agar dilution method, and resistant, when using a broth dilution method. The fact was accounted for the high degree of mutation associated with the haploid state present in this species. Experimental T. glabrata infection in immunocompetent and immunocompromised mice appears not respond to the oral administration of the drug. The results agree with that of broth dilution tests and not with those produced by the agar methods. It seems that agar dilution sensitivity tests are inadequate for yeast species with an high rate of mutation, as T. glabrata.
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  • 4
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    Nutrient cycling in agroecosystems 12 (1987), S. 119-137 
    ISSN: 1573-0867
    Keywords: fertiliser ; nitrogen ; regression ; response ; winter wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Measurements were made of yield of dry matter, plant-N content, and the distribution of mineral-N down the soil profile in 10 fertiliser-N experiments. In one of them detailed measurements were made throughout growth. Rate of N-uptake by the crop was unaffected by the amount of mineral-N in the upper 90 cm of soil when it was above about 30 kg N ha−1. The %N in plants that received ample N-fertiliser declined with increase in plant mass according to a previously derived equation. During senescence there was an apparent loss of N from the crop. N-nutrition in the different experiments had little effect on the partition of assimilate between grain and straw. At harvest grain and straw weights were well related by a linear model which had the same gradient but different intercepts for each experiment. Grain %N was about four times greater than straw %N. Regression analysis supported the view that high evaporative conditions or temperatures during the growing period induced earlier harvest dates, less grain relative to straw, and a higher %N in the plant when ample N-fertiliser was applied but not when N-fertiliser was withheld. Other analyses indicated that cereal roots were generally unable to extract mineral nitrogen from the soil when the concentration was less than about 0.18 kg N ha−1 cm−1, that at low levels of N-nutrition the recovery of available inorganic-N from soil by the grain and straw was about 80%, and that the average mineralisation rates from early spring to shortly after harvest date varied between 0.22 and 0.88 kg N ha−1 d−1 from site to site.
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  • 5
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    Nutrient cycling in agroecosystems 14 (1987), S. 135-142 
    ISSN: 1573-0867
    Keywords: nitrogen ; phosphorus ; soil and crop residues management practices ; maize yield ; Plinthudult ; Cameroon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The shortening of fallow period in several areas in tropical Africa has reduced soil fertility and exposed soils to erosion and run-off. Fertilizer application and crop conservation practices are needeed to sustain high crop yield and to conserve the natural resource base for upland crop production in the continent. Field trials were carried out to evaluate the effect of fertilizer application and soil and crop residues management practices on yield of maize (Zea mays L.) planted on a Plinthudult soil at Bertoua, Eastern Cameroon. Maize yields increased significantly with nitrogen and phosphorus fertilizer application. Under the rainfall pattern prevailing in the area, the amount of nitrogen required for maximum yield was higher in the second season. On the other hand, the amount of phosphorus required for maximum yield appeared to decrease with time. The burning of crop residues and weeds prior to planting together with no-till practive gave higher yield of maize than other soil and crop residues management practices.
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  • 6
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    Nutrient cycling in agroecosystems 15 (1988), S. 173-179 
    ISSN: 1573-0867
    Keywords: Douglas-fir ; urea ; basal area increment ; growth response ; nitrogen ; critical level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A series of fourteen Pacific North-west Douglas-fir installations, ranging in age from 6 to 26 years were analysed with respect to site factors, foliage nutrients, and growth response to applied fertilizer. Unfertilized basal area increment ranged from 1.2 to 3.1 m2 ha−1 yr−1 with no apparent relationship with soil, stand age or site index. Basal area increment was correlated with foliage N and a critical level for N was calculated as 1.7%. Applications of 220 kg N ha−1 as urea increased growth between 0 and 95% of the unfertilized basal area growth, with an average of 24.9%. Response could be predicted from foliage N and unfertilized basal area increment. When the same relationships were applied to previously older stand data, results were more variable as elements such as B and S showed evidence of being limiting.
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  • 7
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    Nutrient cycling in agroecosystems 15 (1988), S. 203-210 
    ISSN: 1573-0867
    Keywords: irrigation ; pineapples ; nitrogen ; potassium ; yield ; Nigeria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The investigation studied the effect of fertilization with four nitrogen levels (0, 100, 150 and 200 kg/ha), four potassium levels (0, 100, 150 and 200 kg/ha) and four irrigation treatments (0, 3, 7 and 14-day interval) on the growth and yield of smooth Cayenne pineapples. Increasing irrigation frequency increased growth parameters of number of leaves, D-leaf length and days to 50% flowering. Fruit weight was highest at N = 150 kg/ha, K = 200 kg/ ha and irrigation once a week. Higher N levels (beyond 150 kg/ha) applied after the plant crop has been harvested did not further enhance yields of the ratoon crop. For K = 200 kg/ha potential and harvested yields were reduced in all irrigation treatments when N 〉 150 kg/ha.
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  • 8
    ISSN: 1573-0867
    Keywords: farmyard manure ; maize ; nitrogen ; phosphorus ; rice ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha−1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha−1 as urea could increase the grain yield of rice equivalent to 120 kg N ha−1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha−1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha−1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils.
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  • 9
    ISSN: 1573-0867
    Keywords: nitrogen ; okra (Abelmoschus esculentus L. Moench) ; phosphorus ; yield ; yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The response of two okra (Abelmoschus esculentus L. Moench) varieties (‘White velvet’ and ‘NHAE 47-4’) to fertilization in northern Nigeria was examined using four rates of nitrogen (0, 25, 50 and 100 kg ha−1) and three rates of phosphorus (0, 13 and 26 kg ha−1). Nitrogen application significantly increased green pod yield, pod diameter, number of fruits per plant, number of seeds per pod and pod weight. Application of phosphorus also significantly increased green pod yield, pod number and number of seeds per pod. The two varieties responded to nitrogen application differentially with respect to green pod yield. For optimum green pod yield of ‘White velvet’ 35 kg N ha−1 is suggested while for variety ‘NHAE 47-4’, N fertilization can be increased to 70 kg ha−1. There was no differential response of varieties to phosphorus fertilization for green pod yield; however, the application of 13 kg ha−1 enhanced the performance of both varieties.
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  • 10
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    Nutrient cycling in agroecosystems 8 (1986), S. 313-328 
    ISSN: 1573-0867
    Keywords: fertilizers ; lime ; lucerne ; nitrogen ; phosphorus ; sewage sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment was conducted with lucerne on a strongly acidic and phosphorus deficient soil to determine the liming and phosphorus and nitrogen fertilizer value of an undigested, lime-treated sewage sludge. The results are presented in terms of calculated combinations of lime, nitrogen and phosphorus fertilizer required to obtain the same lucerne yield (or soil pH or extractable phosphorus level) as achieved with 5 or 10 t ha−1 of dried sludge. The sludge was a good source of lime, phosphorus and nitrogen. The sludge phosphorus was 49% as effective as the fertilizer phosphorus in raising extractable phosphorus in the soil to the level required for crop growth. The calcium carbonate of the sludge raised soil pH more effectively than agricultural lime, probably because of finer particle size in the former. It was not possible to achieve the yield obtained with 25 t ha−1 of sludge with combinations of agricultural lime, and nitrogen and phosphorus fertilizers at high rates of application. This was attributed to the effects of the sludge on improving soil physical properties.
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  • 11
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    Nutrient cycling in agroecosystems 8 (1986), S. 269-278 
    ISSN: 1573-0867
    Keywords: nitrogen ; nitrogen-15 ; nitrogen efficiency ; nitrogen balance ; residual nitrogen ; sugar beet ; spring wheat ; winter rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The recovery of15N labelled ammonium fertilizer was studied during two cropping sequences: sugar beet—spring wheat and winter rye—sugar beet with the labelled N applied to the first crop of each sequence. The difference between fall and spring application was also investigated. For the first cropping sequence 100 kg N ha−1 labelled with 11.4%15N atom excess (a.e.) was applied to the sugar beets. This labelled N was followed in the sugar beets, in the soil profile at harvesting time as well as in the spring wheat of the following year. The first crop of sugar beet recovered 43–46% of the applied N, with 26–29% remaining in the soil at harvesting time and 25–31% could not be accounted for. Of the residual N, less than 1% could be recovered by the next crop of spring wheat. For the second cropping sequence 50 kg N ha−1 labelled with 11.5%15N a.e. was applied to the winter rye and followed in the winter rye and in the sugar beets of the following year. The recovery of the labelled fertilizer N applied to the winter rye of the second sequence was 20–27% and the sugar beets of the next year could only recover 2%. With respect to time of application, no difference in fertilizer N recovery was found between fall or spring application for the two sequences.
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  • 12
    ISSN: 1573-0867
    Keywords: Growth ; nutrient concentration ; nitrogen ; okra (Abelmoschus esculentus L. Moench) phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The growth response and nutrient concentration in okra (Abelmoschus esculentus L. Moench) as influenced by four nitrogen rates (0, 25, 50 and 100 kg ha−1) and three phosphorus rates (0, 13 and 26 kg ha−1) were examined using two varieties (‘White velvet’ and ‘NHAE 47-4’). Nitrogen application generally increased fruit and shoot dry weights markedly whereas phosphorus increased them only moderately. Leaf and primary branch production and plant height were also enhanced by nitrogen fertilization up to 100 kg N ha−1 but were not influenced by phosphorus application. The application of nitrogen enhanced the concentration of N, P and K in fruits and N and Mg in leaves while P and K concentrations in leaves were depressed. Nutrient concentrations in plant tissues were also partly a function of plant age and variety.
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  • 13
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    Nutrient cycling in agroecosystems 9 (1986), S. 187-197 
    ISSN: 1573-0867
    Keywords: lime ; lucerne ; nitrogen ; phosphorus ; ryecorn ; ryegrass ; sewage sludge ; sewage ash
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two field experiments were conducted to compare the fertilizing and liming properties of dried lime-treated sewage sludge with its incineration product (ash). One experiment used a mixture of ryecorn and ryegrass on a relatively fertile soil and the other lucerne on a strongly acidic and phosphorus deficient soil. The first harvest of the ryecorn-ryegrass experiment showed small but significant linear responses in dry matter yield to both ash and sludge. Ash applications did not affect foliage nitrogen and phosphorus concentrations, or uptakes, but sludge applications increased these significantly. Sludge also increased the concentrations of K, S, Mg, Cu and Zn but ash only increased the concentrations of S and Mg. At the second harvest (ryegrass) 5 t ha−1 of sludge increased dry matter yield and foliage nitrogen and phosphorus concentrations whereas ash had no effect. Levels of phosphorus extracted from the soil were increased by both amendments but the sludge was much more effective than the ash. Both ash and sludge raised soil pH. In the lucerne experiment comparisons between sludge and ash were calculated from response surfaces fitted to the data which showed marked increased in soil pH and dry matter yield. Sludge markedly increased extractable phosphorus whereas ash had no effect. The sludge was 22% as effective as ash in raising soil pH to 6.5. The amounts of ash required to obtain the same yield as 10 t ha−1 of sludge were 5.78, 12.78 and 6.39 t ha−1 respectively for three successive harvests. These results and those for foliage concentrations of nitrogen and phosphorus were also ascribed to the much greater availability of the sludge phosphorus than the ash phosphorus, and the presence of nitrogen in the sludge but not in the ash.
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  • 14
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    Nutrient cycling in agroecosystems 10 (1986), S. 97-112 
    ISSN: 1573-0867
    Keywords: fertilizer ; nitrogen ; phosphorus ; plant analysis ; nutritional status
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study consisted of a survey on the nutritional status of rice plants in relation to nutrient application and yield in 70 farmers' fields in four provinces of Bangkok plain during the 1977 wet season. In addition a series of fertilizer experiments were carried out on rice experimental stations in the same provinces to study yield response to N and P fertilization and to develop a fertilizer recommendation system based on plant analysis. The average grain yield in the survey was 3.2 t ha−1 and the early (high yielding varieties), medium (local) and late maturity (local) types yielded 3.3, 2.8 and 3.0 t ha−1, respectively. The average amount of fertilizers applied to these maturity types were 33, 15 and 7 kg N ha−1 and 15, 8 and 6 kg P ha−1, respectively. Regression analysis indicated only a slight correlation between yield and any level of fertilizer application. On experimental stations yields over 6 t ha−1 were obtained with applications of N over 100 kg ha−1 and P over 22 kg ha−1. Evaluation of nutritional status of plants based on plant analysis showed that in all provinces there were strong and widespread nutrient deficiences primarily of N and secondarily of P, and possibly of some other nutrients. Fertilizer application based on plant analysis gave high yield responses. It was concluded that the major constraints of yield on Bangkok plain are too low fertilizer application especially of N, and unbalanced fertilization of N and P.
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  • 15
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    Nutrient cycling in agroecosystems 3 (1982), S. 13-16 
    ISSN: 1573-0867
    Keywords: cocoa ; nitrogen ; phosphorus ; soil analysis ; Nigeria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract No extensive investigation on the effect of fertilizers on Amazon cocoa variety (Theobroma cacao L.) has been performed in Nigeria. Therefore eight fertilizer treatments involving nitrogen and phosphorus, replicated six times at four locations across southern Nigeria, were established in 1973. The four N levels (N0, N1, N2, N3) involved were 0, 80, 160 and 240 kg ha−1 y−1, and the two P levels (P0, P1) were 0 and 67 kg ha−1 y−1. Results of the first 5 years of fertilizer application are reported. Response to P was observed at all locations, and the response was statistically significant at 2 of the locations. There was no response to the application of nitrogen. The data suggest, however, that there is only a response to phosphorus when nitrogen is applied.
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  • 16
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    Nutrient cycling in agroecosystems 3 (1982), S. 17-23 
    ISSN: 1573-0867
    Keywords: nitrogen ; potassium ; fertilization ; Norway spruce ; quartzite ; podzol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In young spruce plantations on mineral soils the growth of the trees is improved by N application only in rare cases, and by P or K application only on sites over parent rock, which is poor in available fractions of these nutrients. Interpretation of a field trial showed that on extremely poor quartzitic soils potassium deficiency limited growth during the first years of crop development. Potassium deficiency ended at pole stage (about 15 years after planting). N deficiency began at sapling stage (about 8 years after planting) and increased later. On quartzitic and similar sites with a low cation-exchange capacity, appropriately phased applications of K and N markedly improve the site index and yield level of young spruce stands. Thus, it was shown that the stock of stemwood can be raised from 3 to 13 m3 per ha up to an age of 16 years.
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  • 17
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    Nutrient cycling in agroecosystems 3 (1982), S. 37-62 
    ISSN: 1573-0867
    Keywords: ammonium-N ; distillation ; fertilizers ; mass spectrometer ; nitrate-N ; nitrogen ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Although the stable isotope15N is an indispensable tool in research to trace the fate of fertilizer nitrogen in soil/plant systems, the analytical methods used in this research are time consuming and prone to many errors. This paper outlines the methods used in an international program of nitrogen research coordinated by the International Fertilizer Development Center (IFDC). The different steps in the digestion, distillation, and isotope ratio analysis of15 N-labeled soils, plant material, and fertilizers are described. Details on the use of a series of controls to check the precision and accuracy of the methods are also given. It is hoped that this comprehensive description of procedures will encourage the expanded and proper use of15N.
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  • 18
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    Nutrient cycling in agroecosystems 3 (1982), S. 379-383 
    ISSN: 1573-0867
    Keywords: band placement ; computer modelling ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A model was developed to describe the distribution of mineral nitrogen when applied in a fertilizer band, taking into account nitrification and diffusion. Good agreement was found between the calculated values and those measured in a field experiment.
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  • 19
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    Nutrient cycling in agroecosystems 11 (1987), S. 25-41 
    ISSN: 1573-0867
    Keywords: fertilizer ; high analysis nutrient compounds ; nitrogen ; phosphorus ; Rhodes grass ; slow-release ; sulphur ; Townsville stylo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The fertilizer potential of two unusual N-P compounds with cage structures was evaluated in pot experiments where plants were repetitively cut over 400 days. One of the compounds, hexamethyl-hexaaza-tetraphosphaadamantane (APA), having 41.6% P and 28.2% N, showed high fertilizer capability. After more than 400 days, dry matter yield of Rhodes grass given APA was 83–102% of that given conventional N-P sources, and yield of Townsville stylo 60–70%. Curves for N and P uptakes over time were of sigmoidal form, with the steepest parts between days 40 and 120, suggesting a slow-release feature. However growth was depressed up to day 40, presumably by some toxic factor associated with the decomposition of the APA. This toxicity was avoided if some conventional fertilizer was applied with the APA. The other compound, the tetrasulphide of APA (APAS) had only limited fertilizer potential. Plants did absorb P and S at least from this compound, but Townsville stylo yield was only 32–38% of that with conventional fertilizers, and Rhodes grass yield not much greater than from control pots. The possible slow-release feature, and the toxic effect, did not occur with APAS.
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  • 20
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    Nutrient cycling in agroecosystems 18 (1988), S. 245-250 
    ISSN: 1573-0867
    Keywords: plantain ; intercropping systems ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The investigation evaluated the productivity of plantain intercropped with cassava, cocoyam and yam, fertilized annually with 0, 320 and 480 kg N ha−1 respectively. Yields from nitrogen fertilized intercrops were higher than those of unfertilized treatments. In plantain + cassava intercrop receiving 480 kg N ha−1 plantain growth was suppressed. Plantain intercropped with yam and fertilized with 320 kg N ha−1 matured early and produced better bunches than other treatments. Plantain + yam or cocoyam intercropping systems fertilized with 320 kg N ha−1 were recommended because of improved plantain establishment and increased combined crop yields.
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  • 21
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    Nutrient cycling in agroecosystems 5 (1984), S. 371-382 
    ISSN: 1573-0867
    Keywords: nitrogen ; phosphorus ; dry areas ; apparent recovery fraction ; fertilizer management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Agronomic efficiency (AE) is defined as the increase in economic yield of a crop per unit fertilizer applied. Components of AE are physiological efficiency and apparent recovery fraction. The latter can be further separated into uptake efficiency and availability index. Ways to increase the nitrogen fertilizer use efficiency in rainfed agriculture through fertilizer management are discussed.
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  • 22
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    Cellular and molecular life sciences 41 (1985), S. 1563-1564 
    ISSN: 1420-9071
    Keywords: Cytosine deaminase ; kinetics ; pyrophosphate ; orotidine monophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The maximal velocity of the reaction (Vmax) and the half-saturation constant (K0.5) values of theS. typhimurium cytosine deaminase were altered in the presence of its effectors, pyrophosphate and orotidine monophosphate. From the kinetics of orotidine monophosphate inhibition of cytosine deaminase, it was characterized as a mixed-type noncompetitive inhibitor.
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  • 23
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    Cellular and molecular life sciences 42 (1986), S. 1057-1058 
    ISSN: 1420-9071
    Keywords: Flies ; pyrethroids ; ethers ; resistance ; kdr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new class of pyrethroids (cyclopropane ethers) is highly effective against susceptible house flies. Its activity is comparable to that of commercial pyrethroids like fenvalerate. On a fly strain with high multi-resistance to organophosphorus and pyrethroid insecticides, and on asuper-kdr strain, these pyrethroids are not very effective; therefore they are unable to break metabolic or target site resistance against ester pyrethroids and DDT.
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  • 24
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    European journal of clinical pharmacology 21 (1981), S. 215-220 
    ISSN: 1432-1041
    Keywords: phenytoin ; cimetidine ; antipyrine test ; drug interaction ; drug metabolism ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a prospective study in nine patients the effects of phenytoin and of cimetidine (1000mg/day) + phenytoin on the antipyrine test and serum phenytoin concentrations were studied. Serum phenytoin increased from the steady state level of 5.7±1.3 mg/l to 9.1±1.4mg/l after three weeks on cimetidine (p〈0.01), and fell to 5.8±1.2 mg/l within two weeks after withdrawal of cimetidine. The protein binding of phenytoin was not changed by cimetidine. After use of phenytoin for 2–4 months, antipyrine clearance increased from 0.67±0.06ml/min/kg to 1.61±0.22 ml/ min/kg, and antipyrine half-live fell from 10.9±1.3h to 4.5±0.6h as compared to the values before phenytoin treatment (p〈0.01). After three weeks combined use of cimetidine and phenytoin, antipyrine clearance was decreased to 1.01±0.07 ml/min/kg and antipyrine half-life was prolonged to 6.1±0.5h, (p〈0.01) compared to the values on phenytoin alone. The distribution volume of antipyrine was not affected by phenytoin nor by cimetidine + phenytoin. The half-life of cimetidine was 2.8±0.3h in the patients on longterm phenytoin treatment. There was a significant positive correlation (p〈0.001) between the increase in serum phenytoin concentration and the prolongation of antipyrine half-life caused by cimetidine. Thus, cimetidine increases serum phenytoin concentration, very probably by inhibiting its metabolism. Care should be taken in the concomitant use of cimetidine and phenytoin, and the dose of phenytoin should be modified according to the clinical symptoms and serum phenytoin concentrations.
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  • 25
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    European journal of clinical pharmacology 22 (1982), S. 225-228 
    ISSN: 1432-1041
    Keywords: pinazepam ; N-desmethyldiazepam ; kinetics ; metabolism ; human
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma profile of a single oral dose of pinazepam 10 mg was studied in 6 healthy male volunteers, aged 26 to 31 years. The concentrations of the parent compound and of its metabolite in plasma were measured by gas-chromatography. The peak plasma levels of pinazepam was 36.8±5.1 ng/ml and of N-desmethyldiazepam 150±13.3 ng/ml. The plasma concentration of the metabolite become higher than that of the parent compound shortly after administration, suggesting that pinazepam acts as a prodrug.
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  • 26
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    European journal of clinical pharmacology 22 (1982), S. 545-551 
    ISSN: 1432-1041
    Keywords: oxcarbazepine ; kinetics ; disposition ; metabolites ; renal excretion ; volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Oxcarbazepine (oxcarb) 600 and 900 mg (2360 and 3540 µmol) was taken by 3 volunteers (2 ♀, 1 ♂; 45–67 kg; age 22–34 years) after an overnight fast. Blood, saliva and urine were collected for the next 72 h for assay of oxcarb, 10,11-dihydro-10-hydroxy-carbamazepine (OHcarb), and 10,11-dihydrotrans-10,11-dihydroxy-carbamazepine (diol). Oxcarb reached a maximum level of about 1 µg/ml (3.93 µmol/l) within 1 h and dropped below the detection limit (0.1 µg/ml=0.39 µmol/l) within 3 h. The active metabolite OHcarb appeared in the blood before oxcarb and reached the higher maximum level of 7.4 µg/ml (29 µmol/l) after 7 h. Thereafter serum levels decreased with a t1/2 of about 25 h, and after 40 h with a t1/2 of 9 h, the latter agreeing with the renal excretory t1/2 calculated from the urine data (10 h). The ratio of OHcarb concentration in saliva to that in plasma varied considerably (0.3–1.7; median 1; r〉0.9), whereas that of blood to plasma was 1.25 with only small variation (r〉0.98); OHcarb concentrations in erythrocytes were 50% higher than in plasma. Diol was detected in blood (maximum level 0.5 µg/ml=1.84 µmol/l) in 2 volunteers. 45% of the dose could be recovered in urine (Oxcarb 5%, OH-carb 36%, Diol 4%). Whereas Oxcarb was completely conjugated, only 25% of OHcarb was conjugated and diol was unconjugated.
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  • 27
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    European journal of clinical pharmacology 24 (1983), S. 217-220 
    ISSN: 1432-1041
    Keywords: metoprolol ; pregnancy ; hypertension ; kinetics ; pre-eclampsia
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of oral metoprolol was studied in 5 women during the last trimester of pregnancy and 3 to 5 months after delivery. After a single oral dose of 100 mg the individual peak plasma concentration in the pregnant state was only 20–40% of that after pregnancy. The plasma half-lives of metoprolol were about the same during (average 1.3 h) and after pregnancy (average 1.7 h). By contrast, the area under the plasma concentration versus time curve was much smallerduring (mean 262 nmol/l×h) thanafter (mean 1298 nmol/l×h) pregnancy, resulting in an average apparent oral clearance (Clo) of metoprolol that was 4.4times higher during (362 ml×kg−1 body-weight×min−1) than after pregnancy. The increased Clo in pregnancy is assumed to be due to enhanced hepatic metabolism of the drug. The possible clinical consequence of the difference in the disposition of metoprolol is discussed.
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  • 28
    ISSN: 1432-1041
    Keywords: prizidilol ; antihypertensive effect ; acute and long-term blood pressure control ; plasma renin activity ; acetylator phenotype ; antinuclear antibodies ; side effects ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After an initial placebo period of four weeks 24 patients with primary hypertension were treated with prizidilol, a hydrazinopyridazine derivative with combined vasodilator and non-selective beta-adrenoceptor blocking actions, for a dose titration period of 14 weeks. Prizidilol 200 to 800 mg was given once daily to achieve a target supine diastolic blood pressure (BP)〈90 mmHg. Supine and standing BP recorded 24–27 h after drug intake decreased from 172±17/106±6 mmHg (mean±SD) and 167±18/111±8 mmHg, respectively, after placebo to 159±16/99±8 and 154±18/101±9 mmHg after active treatment for six weeks (mean dose 447 mg), and to 154±16/97±7 and 148±14/97±7 mmHg after treatment for 14 weeks (mean dose 687 mg/day). A slight reduction in HR was seen after treatment for six weeks and in plasma renin activity and urinary methoxycatecholamine excretion after treatment for 14 weeks. A sustained decrease in BP was observed for 10 h after prizidilol 800 mg (n=9), with a maximum antihypertensive effect (mean reduction in supine BP 33/18 mmHg) 2.5 h after dosing, which coincided with the mean peak plasma concentration. The plasma elimination half-life of the drug was 3.9 h (range 2.0–8.9 h). Changing to a twice daily regimen in 17 patients (mean daily dose 748 mg at six months) did not produce any further reduction in the BP (recorded 12–15 h after dosing) as compared to the once daily regimen at 14 weeks. During treatment for up to 24 months, 16 patients did not achieve satisfactory BP control. Eight of them were withdrawn and eight received additional treatment with bendroflumethiazide (2.5–5 mg/day). In 7 of the latter satisfactory BP control was achieved. Side effects were few. Dizziness and tiredness occurred in four patients 2–5 h after prizidilol 600–800 mg once daily. These symptoms partly subsided when the subjects changed to a twice daily regimen. No ocular side-effects were found. Before treatment 13 out of 24 patients had a low titre of IgM antinuclear antibodies (ANA) and one patient also a low titre of IgG ANA. During treatment the frequency of patients with positive ANA-titres became higher, and after treatment for 12 months (n=17) 15 patients had positive IgM and seven patients positive IgG ANA-titres. However, the titres were low and no patient showed a clinical lupus erythematosus syndrome. There was no relation between acetylator phenotype of the patient and acute or longterm effecton BP, pharmacokinetics of the drug or the development of a raised ANA-titre.
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  • 29
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    European journal of clinical pharmacology 24 (1983), S. 273-276 
    ISSN: 1432-1041
    Keywords: undernourished ; chlorquine ; kinetics ; plasma levels ; red cell uptake
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma and whole blood kinetics of chloroquine was studied in 7 normal and 8 undernourished subjects following a single oral dose of 600 mg. The terminal half-lives were similar in both groups. The AUC was also similar in the 2 groups, even though a higher dose per kg body weight was administered to the undernourished. This was probably because of faster clearance in this group. Chloroquine uptake by erythrocytes, its main site of action in malaria, was also comparable in the two groups. The plasma concentration of chloroquine over a period of time was found to be similar in 4 normal and 4 undernourished subjects following administration of 1.5 g of the drug in divided doses. The undernourished appear, therefore, to handle chloroquine in such a way that they do not suffer a greater risk of toxicity than normals.
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  • 30
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    European journal of clinical pharmacology 24 (1983), S. 525-527 
    ISSN: 1432-1041
    Keywords: theophylline ; airway obstruction ; biotransformation ; kinetics ; oral dosage
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Oral theophylline was given to 6 adults with airways obstruction. The initial dose was 125 mg daily and this was increased by 125 mg each week. The final total daily dose reached was determined by side effects and ranged from 500 mg to 1125 mg. At the end of each week and before the next dosage increment steady state, trough plasma theophylline concentrations were measured. For each individual and for the group as a whole there was a highly significant linear correlation between theophylline dose and trough plasma concentration. This indicates that for oral theophylline, in adults, dose-dependent kinetics do not play a significant role and dose may be adjusted without fear of a disproportionate rise in plasma concentration.
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  • 31
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    European journal of clinical pharmacology 27 (1984), S. 491-494 
    ISSN: 1432-1041
    Keywords: amiodarone ; kinetics ; volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We studied three healthy volunteers after a single i.v. bolus of amiodarone, during 1 month of chronic oral dosing and after the discontinuation of the drug. Blood concentrations of amiodarone declined rapidly in a bi-exponential fashion after i.v. bolus. The terminal half-life ranged from 10 to 17 h; after discontinuation of chronic treatment the terminal half-lives were 8–21 days. The i.v. data, the trough levels during multiple dosing and the washout phase could be simultaneously fitted using a tri-exponential equation. The subjects were carefully monitored for cardiac and thyroid function. One subject had to stop taking amiodarone because of profound bradycardia. A reduction of serum TT3 and FT3 concentrations and an increase of serum rT3 and FT4 was found.
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  • 32
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    European journal of clinical pharmacology 29 (1985), S. 251-253 
    ISSN: 1432-1041
    Keywords: paracetamol ; antacids ; acetaminophen ; bioavailability ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of two antacids on the bioavailability of paracetamol has been investigated in 12 young healthy volunteers. Following a random cross over design, each subject swallowed, on three separate occasions, one weak apart, 500 mg paracetamol alone, or together with two different aluminium hydroxide, magnesium hydroxide preparations (Dimalan and Maalox). Plasma paracetamol levels were measured by HPLC. The bioavailability of paracetamol was not altered by either antacid, but they both delayed the time to peak plasma concentration (0.85 h; 1.43 h; 1.25 h, without antacid, with Dimalan and with Maalox respectively). The peak plasma concentration was not affected by concurrent antacid administration.
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  • 33
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    European journal of clinical pharmacology 28 (1985), S. 163-169 
    ISSN: 1432-1041
    Keywords: indomethacin ; platelet aggregation ; prostanoids ; plasma concentration ; arachidonic acid ; thromboxane B2 ; 6-keto-prostaglandin F1α ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A single oral dose of indomethacin 1 mg/kg was given to 6 male and 6 female volunteers. The formation of thromboxane B2 (TXB2) and 6-ketoprostaglandin F1α (6-keto-PGF1α) in clotting whole blood was measured by radioimmunoassay, and platelet aggregation induced by archidonic acid (AA) was measured with a plasma aggregometer. The results were related to the concomitant plasma concentration of indomethacin. The maximum plasma concentration ranged between 3.24 and 8.11 µg/ml and the elimination half-life between 4 and 11 h. Formation of the prostanoids was reversibly inhibited, with maximum suppression when the drug concentration in plasma exceeded 0.5–1.0 µg/ml; the IC50 was approximately 0.1 µg/ml. Platelet aggregation was also reversibly inhibited. The correlation between the formation of prostanoids and the different phases of the aggregatory response to exogenous AA is discussed.
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  • 34
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    European journal of clinical pharmacology 17 (1980), S. 285-293 
    ISSN: 1432-1041
    Keywords: tolbutamide ; chlorpropamide ; kinetics ; food ; age ; blood glucose ; plasma insulin
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake (standardized breakfast) on the oral single-dose kinetics and effects of tolbutamide (0.5 g) and chlorpropamide (250 mg) was investigated in young, healthy volunteers. The single-dose kinetics of the two drugs was also studied in elderly healthy subjects. There was great interindividual variation in the elimination rate of both drugs, but food intake influenced neither their AUCs nor their rates of absorption and elimination. The peak concentration of chlorpropamide, but not that of tolbutamide, was reduced by food intake. The peak concentrations of serum tolbutamide were approximately doubled by an increase in dose from 0.5 to 1.0 g, and from 1.0 to 2.0 g. At no time did tolbutamide 0.5 g affect the plasma insulin level, neither in the fasting nor in the non-fasting state. However, this dose did reduce the blood glucose level during fasting and the increase in blood glucose in response to the meal. The latter effect was recorded within 30 min, when the serum level of tolbutamide still was close to zero. Plasma insulin concentrations did increase within 30 min after a higher dose of tolbutamide (1.0 g), when the serum concentration of tolbutamide was about 50 µmol/l. Between 2.5 and 8 h after administration of chlorpropamide 250 mg, serum drug concentrations were lower than those following tolbutamide 0.5 g. The blood glucose response was smaller and occurred later, being significant at 2 h, when the serum concentration of the drug was about 70 µmol/l. There was no significant change in plasma insulin. There was no significant pharmacokinetic difference between young and elderly subjects, except that the peak concentration of tolbutamide was higher in the latter. It appears that both for tolbutamide and chlorpropamide there is great interindividual variation in drug disposition, but food intake does not influence the bioavailability of either drug. The effect of any particular drug concentration seems dependent upon the blood glucose level and hence upon the elapsed time since the last meal. Both drugs can reduce blood glucose without an alteration in the peripheral blood concentration of insulin. This may reflect an extrapancreatic effect of the drugs, but it could also be an expression of increased insulin secretion, which is not detected because of enhanced hepatic degradation of the hormone released into the portal circulation. The observations made in young individuals are also probably relevant for elderly subjects.
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  • 35
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    European journal of clinical pharmacology 21 (1982), S. 403-408 
    ISSN: 1432-1041
    Keywords: glibenclamide ; diabetes ; insulin ; kinetics ; blood glucose ; relationship to meals ; absorption
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an attempt to assess whether intake of glibenclamide before meals would improve its therapeutic capacity, the present investigation compared the effect of glibenclamide 2.5mg t.i.d. given before and together with meals. In addition, these effects were compared with that of glibenclamide given as a single morning dose of 7.5mg. The subjects studied were six Type 2 diabetics not previously exposed to sulphonylurea drugs. Irrespective of dosage and mode of administration, addition of glibenclamide to a standardized breakfast, lunch and dinner enhanced plasma IRI concentrations and reduced blood glucose concentrations as compared to administration of meals without the drug. The different modes of glibenclamide administration did not differ significantly with respect to IRI responses. However, the blood glucose reduction after breakfast was significantly greater when glibenclaimde 2.5mg had been given before the meal than when 2.5 or 7.5mg were given with the meal; a similar, but non-significant tendency was observed after lunch; no consistent difference was seen after dinner. Food intake did not affect glibenclamide kinetics. It appears that administration of glibenclamide 2.5mg before breakfast improved glucose utilization following the breakfast load, due to earlier attainment of an effective concentration of glibenclamide.
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  • 36
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    European journal of clinical pharmacology 22 (1982), S. 309-314 
    ISSN: 1432-1041
    Keywords: acetylsalicylic acid ; salicylic acid ; dipyridamol ; bioavailability ; kinetics ; rapid- and slow-release formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Acetylsalicylic acid (ASA) is a strong, irreversible inhibitor of platelet aggregation, but loses this activity following first-pass deacetylation to salicylic acid (SA). In order to compare the bioavailability of unchanged ASA from rapid- and slow-release formulations, the single-dose concentration profiles of ASA and SA were studied in healthy volunteers following intake of two different rapid-release (conventional and effervescent tablets) and three different slow-release (microencapsulated ASA in tablets and in capsules, and enteric-coated tablets) formulations of ASA, and of one slow-release formulation of sodium salicylate. Since anti-platelet therapy with ASA is often combined with dipyridamol, the influence of this drug was also examined. The concentrations of ASA and SA were measured by high-pressure liquid chromatography. While the bioavailability of SA from the 5 ASA formulations was essentially equal and similar to that of the salicylate formulation, the bioavailability and peak concentrations of ASA appeared to be the much greater after rapid-release than after slow-release formulations. Indeed, ASA was only rarely detected in systemic blood following intake of slow-release ASA. Co-administered dipyridamol did not significantly influence the kinetics of ASA or SA. It appears that rapid-release formulations of ASA should be prefered in anti-platelet therapy, either alone or in combination with dipyridamol.
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  • 37
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    European journal of clinical pharmacology 24 (1983), S. 41-47 
    ISSN: 1432-1041
    Keywords: quinidine ; digoxin ; interaction ; kinetics ; absorption ; elimination
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To evaluate the possible effect of quinidine on digoxin bioavailability, the steady state digoxin kinetics was examined with and without concomitant quinidine therapy, in 7 cardiac patients after simultaneous administration of oral digoxin and intravenous [3H]-digoxin. In the presence of quinidine, the absorption rate constant of digoxin (ka) increased from 2.72±1.04 to 3.53±1.34 h−1 (p〈0.05), whereas lag time and peak time decreased from 0.16±0.10 to 0.05±0.04 h (p〈0.05) and from 0.92±0.27 to 0.69±0.19 h (p〈0.02), respectively. Predose plasma digoxin increased from 0.41±0.25 to 0.70±0.31 ng/ml (p〈0.02), while peak plasma digoxin increased from 0.93±0.34 to 1.63±0.46 ng/ml (p〈0.02). The systemic availability of digoxin increased from 68.48±13.35 to 79.09±14.89% (p〈0.05) in the presence of quinidine. Quinidine had no effect on the biotransformation pattern of digoxin, as assessed by thin layer chromatography. Quinidine increases the rate and extent of digoxin absorption, and this interaction contributes significantly to the elevation in plasma digoxin during both its distribution and elimination phases.
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  • 38
    ISSN: 1432-1041
    Keywords: lorcainide ; oral antiarrhythmic therapy ; nor-lorcainide ; first-pass metabolism ; kinetics ; alternative dosage ; regimens
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The feasibility of giving a supplementary starting dose of the antiarrhythmic drug lorcainide, in order to minimalize the impact of the extensive, but saturable first-pass metabolism, was evaluated. Twenty-five adult patients were given 100 mg lorcainide tablets according to one of 3 different dosage schedules: Eight patients took one tablet at 0, 12 and 24h, 8 took 1 tablet at 0, 1, 12 and 24h and 9 took 1 tablet at 0, 2, 12 and 24h. Levels of lorcainide and its metabolite, nor-lorcainide, during treatment were determined by gas-liquid chromatography. The results show that giving a second tablet 1 or 2h after the first may produce faster saturation of the pre-systemic metabolism of lorcainide in the liver.
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  • 39
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    European journal of clinical pharmacology 24 (1983), S. 801-806 
    ISSN: 1432-1041
    Keywords: acebutolol ; hydrochlorothiazide ; kinetics ; drug combination ; interaction ; diacetolol ; healthy subjects ; renal clearance
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of acebutolol and hydrochlorothiazide (HCT) alone or in combination were studied in 12 healthy subjects in a cross over study. Acebutolol and diacetolol (the main metabolite) in plasma and urine were determined by HPLC and hydrochlorothiazide by GLC. The main pharmacokinetic parameters of acebutolol did not differ significantly: AUC 4492±272 µg l−1 h given alone versus 4118±354 µg l−1 h with HCT, half-life (7,69±0,32 h vs 8,10±0,72 h) and renal clearance (13,1±0,5 lh−1 vs 13,8±0,9 lh−1), respectively. There was no difference in diacetolol pharmacokinetics. HCT values were not significantly different: AUC 784±48 µg l−1 h given alone and 720±42 µg l−1 h with acebutolol, t1/2 (4,79±0,37 h vs 4,73±0,43 h). The renal clearance was slightly higher when HCT was given with acebutolol (26,2±2,6 vs 20,3±2,11 h−1,p〈0,05). This increase, observed during the first four hours, was probably due to competition between the drugs for binding to red blood cells.
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  • 40
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    European journal of clinical pharmacology 23 (1982), S. 261-266 
    ISSN: 1432-1041
    Keywords: mexiletine ; rifampicin ; kinetics ; enzyme induction ; excretion ; antipyrine clearance ; dosage adjustment
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To study the effects of enzyme induction on its pharmacokinetics, a single oral dose of the new antiarrhythmic agent mexiletine hydrochloride 400 mg was administered to 8 healthy volunteers before and after treatment with rifampicin 300 mg b.i.d. for ten days. The absorption and distribution of mexiletine were not changed after rifampicin, but its elimination half-life fell from 8.5±0.8 h (mean±SE) to 5.0±0.4 h (p〈0.01), and its nonrenal clearance increased from 435±68 ml/min to 711±101 ml/min (p〈0.01). The mean renal clearance of mexiletine did not change, but it showed an exponential correlation with urinary pH. The amount of unchanged mexiletine excreted in urine over two days decreased from 32±7 to 18±3 mg (p〈0.01). The half-life of antipyrine fell from 11.8±0.4 to 5.5±0.3 h and its clearance increased from 40±3 ml to 74±3 ml/min (p〈0.01). There was a significant (p〈0.05) positive linear correlation between both the half-lives and the clearances of antipyrine and mexiletine. The clearances were positively correlated with serum γ-glutamyl transpeptidase. The results suggest that the dosage of mexiletine should be adjusted when enzyme inducing drugs are started or stopped during therapy with it.
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  • 41
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    European journal of clinical pharmacology 29 (1986), S. 529-534 
    ISSN: 1432-1041
    Keywords: pethidine ; epidural injections ; pain scores ; kinetics ; spinal cord
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty-one patients who had undergone total hip replacement were randomly assigned to one of three groups in order to compare a single dose of 1 mg/kg of pethidine im (I) and 20 mg (II) or 60 mg of extradural pethidine (III) in a double-blind design. The degree of analgesia, the adverse effects, and the kinetics were studied for 18 h. Pain was monitored using a visual analogue scale (VAS). Supplementary doses of oxycodone if required were given no earlier than 0.75 h after pethidine. Plasma concentrations of pethidine were measured with gas chromatography mass spectrometry (GCMS). Hypoalgesia to pin prick test was evaluated. Low pain scores were observed in the extradural groups between 0.25 and 1.5 h after the dose. A significant difference in pain score compared with the im group was found after the higher extradural dose only between 0.5 and 1 h (p〈0.05). The area under the curve (AUC) of pain score versus time (0–18 h) was not significantly different between groups. The recorded adverse effects were minor in all three groups. The terminal half-lives and plasma clearances of pethidine, and the time to peak concentration were not different between the groups. Single patients in the extradural groups showed hypoalgesia to pin prick in parallel to the effect. The present study shows that extradural pethidine produces shortlived analgesia, in contrast to the long-lasting effect of morphine found in other studies.
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  • 42
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    European journal of clinical pharmacology 23 (1982), S. 87-92 
    ISSN: 1432-1041
    Keywords: phenobarbital ; epilepsy ; kinetics ; bioavailability ; epileptic patients
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of phenobarbital (PB) were evaluated in six normal subjects and six epileptic patients treated with phenytoin or carbamazepine. Each normal subject received three single doses of PB: PB-sodium 130 mg i.v. (IV), PB sodium 130 mg i.m. (IM), and PB acid 100 mg orally (PO), in random order at least one month apart. After IV PB distributive half-lives varied from 0.13 to 0.70 h, disposition half-lives were 75 to 126 h, steady state volume of distribution (Vss) was 0.54±0.03 l/kg, and clearance (CL) was 3.8±0.77 ml/h/kg. Absolute bioavailability of IM PB was 101±13%, of PO PB (corrected for dose) 100±11%. Peak serum PB concentrations were achieved from 2 to 8 h after IM administration, and from 0.5 to 4 h after PO administration. Epileptic patients exhibited similar PB kinetics: disposition half-lives were 77 to 128 h, Vss 0.61±0.05 l/kg, and Cl 3.9±0.76 ml/h/kg. Phenobarbital appears to represent an exception among antiepileptic drugs, in that pharmacokinetic data obtained in normals can reasonably be extrapolated to the epileptic population.
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  • 43
    ISSN: 1432-1041
    Keywords: metoprolol ; age ; disposition ; elderly subjects ; kinetics ; metabolism ; alpha-OH-metoprolol
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption and disposition of metoprolol have been evaluated in 10 healthy, non-smoking, elderly individuals (mean age 73.1 years) by simultaneous determination of [3H]-metoprolol and unlabelled metoprolol. The labelled drug was given as an intravenous tracer dose, immediately followed by oral metoprolol 25 mg. The experiment was preceded by administration of metoprolol 25 mg b.i.d. for 3 days. The volume of distribution, elimination half-life and total body clearance were almost the same as previously observed in healthy, young subjects. The mean systemic availability was about 39% in the elderly, which is lower than the mean of 55% observed in a control group of young volunteers who received 50 mg b.i.d. In the elderly, the mean plasma concentration of α-OH-metoprolol was about twice as high as that of the parent drug, whereas the opposite was true of the control group. The results indicate that age-related physiological changes have a negligible effect on the pharmacokinetics of metoprolol.
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  • 44
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    European journal of clinical pharmacology 21 (1981), S. 149-153 
    ISSN: 1432-1041
    Keywords: cinromide ; epilepsy ; kinetics ; metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Cinromide is an experimental anticonvulsant currently in phase II testing. A single oral dose (900 mg) of cinromide was administered to 8 epileptic subjects on phenytoin therapy. Plasma samples drawn during the next 36 h were analyzed for cinromide and its amide and acid metabolites. The absorption rate of cinromide varied widely between subjects producing maximum cinromide concentrations between 0.5 and 2.5 h after the dose. The median elimination half lives of cinromide and the amide and acid metabolites were 0.73, 1.65, and 4.85 h respectively. The oral clearance of cinromide (median=135 l/h) suggests that it is subject to first pass metabolism. In all subjects the area under the curve (AUC) of acid metabolite (632 to 1777 µM/l) was greater than the AUC of amide metabolite (77 to 185 µM/l) which was greater than the AUC of cinromide (5 to 89 µM/l). Steady-state concentration ratios of metabolite to parent drug predicted from the AUC data were 3.8 for the amide and 35.8 for the acid metabolite. The amide metabolite is known to have anticonvulsant properties and, until the relative contributions of metabolites and parent drug to the efficacy of cinromide are resolved, the monitoring of metabolites as well as parent drug is imperative.
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  • 45
    ISSN: 1432-1041
    Keywords: hyperthyroidism ; propranolol ; methimazole ; metoprolol ; atenolol ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetic profiles of oral methimazole 40mg, propranolol 80mg, metoprolol 100mg and atenolol 100mg were compared in hyperthyroid patients both during the hyper-and euthyroid states. For methimazole, neither the peak concentration (Cmax), the time to reach peak concentration (tmax), the elimination half-life (t1/2) nor the area under the curve (AUC) value was affected by the hyperthyroid state. For propranolol and metoprolol, which undergo extensive presystemic clearance, the AUC values were lower (p〈0.02) when the patients were hyperthyroid than when they had become euthyroid, but the t1/2's were not significantly altered. For atenolol, there were no significant kinetic differences between the hyperthyroid and euthyroid states. The findings are compatible with the assumption that hyperthyroidism does not affect the kinetics of methimazole or atenolol, but that it may enhance presystemic clearance of propranolol and metoprolol.
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  • 46
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    European journal of clinical pharmacology 27 (1984), S. 233-236 
    ISSN: 1432-1041
    Keywords: glibenclamide ; acarbose ; kinetics ; alpha-glucosidase inhibitor ; blood glucose control ; plasma insulin ; Type 2 diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A single dose of glibenclamide 5 mg was administered to six Type 2 diabetics, randomly treated for 7 days either with acarbose (3×100 mg daily) or with placebo. The serum concentration of the drug was measured for 10 h. Peak concentrations, times-to-peak concentration, elimination half-lives and the extent of bioavailability of the drug were not significantly modified by acarbose. The combined administration of glibenclamide and acarbose resulted in a modest improvement in the blood glucose profile after breakfast and lunch, together with a significant diminution in plasma insulin. Thus, acarbose appears a useful additional treatment for Type 2 diabetics already receiving sulphonylurea derivatives.
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  • 47
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    European journal of clinical pharmacology 26 (1984), S. 521-530 
    ISSN: 1432-1041
    Keywords: chloroquine ; malaria ; rheumatoid disease ; kinetics ; major metabolite ; optimal dosage ; therapeutic regime ; monodesethylchloroquine ; bidesethylchloroquine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics and disposition of chloroquine (CQ) and its metabolite monodesethylchloroquine (CQM) were investigated in 5 healthy volunteers after incremental (150–300–600 mg CQ base) single oral doses of CQ. The analytical method used (HPLC and fluorescence detection) is the most sensitive known method for CQ and CQM. Plasma and whole blood concentrations of CQ, CQM and a third metabolite, bidesethylchloroquine (CQMM), were determined. The kinetics of CQ was found to be unique. The best fit was obtained by a multicompartmental model. The biological half-life appeared to be between 30–60 days; the volume of distribution (Vd) was ∼ 800l/kg, and the clearance ∼ 11/h/kg when calculated from plasma data. The whole blood concentrations were ∼ 8–10 times higher than in plasma, and consequently the Vd and whole blood clearance were ∼ 10 times lower. The kinetics changed as the dose was increased. An indication of capacity-limited steps in CQ disposition was found, as the rate constants decreased even though the clearance remained the same. The intrinsic half-life of CQM was 1/4 of that of CQ, but was prolonged after the highest dose of CQ. The present knowledge of CQ kinetics could provide a basis for revision of current dosage regimens in malaria suppression and rheumatoid disease to ensure efficacious and safe therapy.
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  • 48
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    European journal of clinical pharmacology 27 (1984), S. 367-369 
    ISSN: 1432-1041
    Keywords: flurbiprofen ; syrup ; suppository ; kinetics ; children ; bioavailability
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eight subjects, aged 6–12 years and weighing 18.8–36.7 kg, received single doses of flurbiprofen 50 or 75 mg (corresponding to 1.4–2.7 mg/kg) as syrup and suppository in a Latin square design. Half-life (2.7–3.2 h), elimination constant (0.22–0.26 h−1), area under the plasma level curve (72.4–77.3 µg·h·ml−1) and time to reach the concentration peak (1–0.75 h) were similar after the syrup and suppository. Flurbiprofen showed equivalent bioavailability after oral and rectal administration and the same pharmacokinetic profile was confirmed in children as observed in adults.
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  • 49
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    European journal of clinical pharmacology 22 (1982), S. 39-45 
    ISSN: 1432-1041
    Keywords: furosemide ; neonates ; kinetics ; placental transfer ; intravenous therapy
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of furosemide was evaluated in 12 newborns who received the drug transplacentally, and in 21 neonates who received it directly for therapeutic reasons. In the first group, the apparent plasma half-lives ranged from 96 to 6.8 h with a significant inverse relationship (p〈0.01) between the gestational age and the elimination rate. In two cases a clear effect on diuresis was also observed. In the neonates receiving the drug i.v. for therapeutic reasons, the elimination kinetics appeared to follow a two-compartment open model, with a significant difference in the therminal plasma half-life between premature (26.8±12.2 h) and full-term newborns (13.4±8.6 h). In this group no relationship was observed between elimination rate and either gestational or conceptional age. In the case of repeated administration, an increase in plasma clearance and reduction in t1/2 β was noticed.
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  • 50
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    European journal of clinical pharmacology 22 (1982), S. 435-439 
    ISSN: 1432-1041
    Keywords: azlocillin ; kinetics ; biliary excretion ; liver dysfunction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic of azlocillin was followed in five elderly patients after biliary surgery. Total clearance was 138.6±17.7 ml/min when 2.0 g was given as an i.v. bolus injection. The half-life of the β-phase averaged 110 min. The total clearance and the half-life of azlocillin were influenced by slight impairment of renal function (creatinine clearance 59.4±13.6 ml/min). In patients with normal liver function biliary excretion of the drug amounted to 5.3±2.8% of the dose (n=3) and the kinetics of biliary excretion were linear. In contrast, in two patients with impaired liver function biliary excretion was 0.2% and 0.5% of the dose, and kinetic analysis of biliary excretion rates revealed at least one zero order step in the excretion process. Renal excretion of the drug amounted to 45.0±17.7% of the dose, which means that 50% of the total clearance of azlocillin has to be accounted for by metabolic clearance.
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  • 51
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    European journal of clinical pharmacology 23 (1982), S. 529-533 
    ISSN: 1432-1041
    Keywords: beta-blocker ; bufuralol ; enantiomers ; kinetics ; metabolism ; man
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Single oral doses of (+)-, (−)- and (±)-bufuralol were administered to a healthy volunteer to compare the disposition and metabolism of the individual isomers and the racemate. Plasma levels and area under plasma curve (AUC) of the active isomer, (−)-bufuralol, were higher than those of the (+)-isomer; plasma clearance was correspondingly lower. Intermediate values were found for the racemate. The elimination half-life of (−)-bufuralol was shorter than that of (+)-bufuralol, but similar to the racemate. Both isomers were cleared almost entirely by metabolism. The main metabolic pathway for (−)-bufuralol was aromatic hydroxylation, whereas the principal route for (+)-bufuralol was conjugation. Phenol metabolites in the systemic circulation were present mainly as conjugates. Both isomers also underwent aliphatic hydroxylation. This pathway was more favoured by the (+)-isomer, although plasma levels and AUC of the principal product, 2′-hydroxy-bufuralol, were almost identical for the two forms. Major differences in metabolic fate thus had relatively little effect on the disposition of pharmacologically active metabolites.
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  • 52
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    European journal of clinical pharmacology 24 (1983), S. 243-246 
    ISSN: 1432-1041
    Keywords: tolbutamide ; valproate ; intoxication ; activated charcoal ; inhibition of absorption ; sulphonylureas ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The claim that activated charcoal should be ineffective or even contraindicated in intoxication due to tolbutamide is based only on limited in vitro studies. To test the claim, the effect of activated charcoal 50 g on the absorption of tolbutamide and, as a reference, of sodium valproate, was studied in 6 healthy volunteers. Each volunteer swallowed tolbutamide 500 mg and sodium valproate 300 mg with 50 ml water 1 h after a light breakfast, and within 5 min they took in randomized order either a suspension of activated charcoal or water. The absorption of tolbutamide, calculated as the peak concentration and the area under the serum drug concentration-time curve during 0–48 h, was reduced by 90% by charcoal (p〈0.001). The absorption of valproate in these conditions was reduced on average by 65% (p〈0.01). In each subject charcoal had a greater effect on the absorption of tolbutamide than of valproate. According to these findings and preliminary in vitro studies on other sulphonylureas high doses of activated charcoal can be recommended for the preventing the absorption of sulphonylureas in acute intoxications. The poor aqueous solubility of these substances at the gastric pH probably delays their gastrointestinal absorption, so that they may be adsorbed on to charcoal even given several hours later.
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  • 53
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    European journal of clinical pharmacology 22 (1982), S. 27-32 
    ISSN: 1432-1041
    Keywords: sulfonylureas ; diabetes ; chlorpropamide ; glipizide ; C-peptide ; insulin ; blood glucose ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of sulfonylurea on the secretion, disposal and effect of insulin was studied in 9 Type 2 diabetics during 3 one-month courses of treatment with a) chlorpropamide (t1/2〉24 h) once daily, b) glipizide (t1/2=2–4 h) once daily, and c) glipizide in divided doses. Food intake by each patient was identical during each period. Blood concentrations of immunoreactive insulin (IRI) and C-peptide (radioimmunoassays), and of glucose (enzymatic assay), chlorpropamide (gas chromatography) and glipizide (high-pressure liquid chromatography) were determined before and after breakfast and lunch on the 4th day of each examination period. All comparisons were intraindividual. Despite the lunch-time dose of glipizide given during the divided dose treatment, once-daily administration of this drug led to higher drug concentrations not only after breakfast but also for the first few hours after lunch. Divided dosage, on the other hand, led to higher concentrations later. In contrast to once-daily dosage, continuous exposure to glipizide was found in most patients. Chlorpropamide gave the most continuous sulfonylurea exposure. The blood glucose levels were inversely related to the concurrent sulfonylurea concentrations; glucose levels after breakfast and lunch were lowest during once-daily glipizide, whereas the fasting level was lowest during chlorpropamide treatment. The IRI response to breakfast was 60%–70% higher during once-daily glipizide than during the other two treatments, but the C-peptide responses to breakfast were almost identical. Thus, the greater after-breakfast availability of peripheral insulin appeared to be due to an effect of glipizide on the extrapancreatic disposal of the hormone.
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  • 54
    ISSN: 1432-1041
    Keywords: digoxin ; verapamil ; digoxin-verapamil interaction ; kinetics ; plasma level ; renal clearance ; extra-renal clearance
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Single-dose investigations in healthy subjects have demonstrated substantial impairment of renal and extrarenal clearance of digoxin during coadministration of verapamil. A longitudinal study has been performed to assess the changes in digoxin disposition during long-term verapamil therapy. After one week of verapamil 240 mg/d mean plasma digoxin had risen from 0.21±0.01 ng/ml (SE) to 0.34±0.01 ng/ml (p〈0.01), and renal digoxin clearance had fallen from 197.57±17.37 ml/min to 128.20±10.33 ml/min (p〈0.001). These changes gradually subsided, and after six weeks, renal digoxin clearance had normalized and plasma digoxin had declined to 0.27±0.02 ng/ml (NS). The 24-h urinary recovery of digoxin increased from 46.46±3.23% before to 69.78±3.69% (p〈0.001) after six weeks of verapamil co-administration, and this elevation persisted throughout the study. The verapamil-induced suppression of renal digoxin elimination disappears over a few weeks of drug exposure, whereas the inhibition of the extrarenal clearance of digoxin seems to persist.
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    Molecular and cellular biochemistry 86 (1989), S. 65-70 
    ISSN: 1573-4919
    Keywords: Hex A ; Hex B ; N-acetyl-glucosaminidases ; kinetics ; thermodynamic transitions ; ion-exchangers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetic and thermodynamic properties of N-acetyl-β-D-glucosaminidase A (Hex A) and N-acetyl-β-D-D-glucosaminidase β (Hex B) from goat testes were investigated in free and bound (after binding them on ion-exchangers such as DEAE- or CM-cellulose respectively) forms. The optimum pH of free Hex A and Hex B was at 4.2 and 5.4, whereas the bound forms showed the optimum pH at 4.0 and 5.2 respectively. While apparent Km of free and bound Hex A (0.8 and 1.0 mM respectively) did not differ, the Km of Hex B increased when bound on CM-cellulose (Km of free Hex B = 0.96 mM versus bound Hex B = 1.6 mM). Though the free Hex A was more thermo-labile than the free Hex B, both isozymes, on insoluble matrices decayed at faster rates on heating. Activation analysis revealed that the energy of activation (E infa supo ) for transition state of free Hex B (81 Kcal deg−1 mole−1) did not differ from E infa supo of bound Hex B. On the other hand, E infa supo of free Hex A declined from 77.2 to 71.1 Kcal deg−1 mole−1 when heat transitions were carried out in free and bound state respectively. Thermodynamic analysis suggested a change in entropy of activation (ΔS*) of free Hex A and Hex B as 200 and 211 eu respectively. While ΔS* of Hex B did not change after heat transitions, ΔS* of Hex A was 182.5 eu.
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    Molecular and cellular biochemistry 64 (1984), S. 45-50 
    ISSN: 1573-4919
    Keywords: cardiac muscle ; kinetics ; pyruvate kinase
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The mechanism of activation by inorganic phosphate and ATP of cardiac muscle pyruvate kinase was studied with the aid of steady-state kinetics. The enzyme was purified to homogeneity to a final specific activity of 400 units/ mg (phosphate buffer, pH 7.6, 25 °C). At pH 7.6 the enzyme displays Michaelis-Menten kinetics with respect to both its substrates, phosphoenolpyruvate and ADP. Substrate kinetic constants are: app.Km(phosphoenolpyruvate) −0.04 mM, app.Km(ADP) =0.22 mM. Under the conditions used in the standard assay the specific activity is greatly enhanced by inorganic phosphate (50 mM) or ATP (2.5 mM). Each of these modifiers, acting separately, increases the Vmax without seriously affecting Michaelis constants and Hill coefficients. In the presence of both Pi and ATP, only a decrease in Vmax was observed. The kinetics of activation by inorganic phosphate of pyruvate kinase was examined. Studying the effect of varying concentrations of Pi on the initial rate we obtained a hyperbolic saturation curve with the app. Km(Pi) = 20 mM and Vmax = 167 units/ mg. The evidence is presented that inorganic phosphate is a substrate for a side reaction catalyzed by cardiac pyruvate kinase. It is shown that in the presence of pyruvate, inorganic phosphate and ATP in the assay system, Pi is incorporated into acid-labile products of this reaction, inorganic pyrophosphate being one of them. These findings indicate the existence of an alternative reaction catalyzed by pyruvate kinase by which energy may be stored in the form of inorganic pyrophosphate.
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  • 57
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    Molecular and cellular biochemistry 86 (1989), S. 171-179 
    ISSN: 1573-4919
    Keywords: porcine glucokinase ; purification ; kinetics ; sulfhydryl-related states
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Porcine hepatic glucokinase (ATP: D-hexose 6-phosphotransferase EC 2.7.1.1) has been purified by a modification of the procedure for its purification from rats. However, difficulties were encountered with endogenous proteases and the reliability of a source for porcine livers. The molecular weight has been determined to be 60 400 ± 1400 by sodium dodecyl sulfate, polyacrylamide gel electrophoresis. The enzyme has been characterized kinetically. The parameter values, S 0.5 (glucose) and Hill coefficient (nH) are 2.4 mM and 1.9 respectively under sulfhydryl-reducing conditions. The enzyme undergoes the two sulfhydryl-related decays of its activity previously observed in the enzyme isolated from rat (Tippett PS, Neet KE: Arch Biochem Biophys 222:285–298, 1983). The enzyme is inhibited by palmitoyl-CoA, K i (apparent) = 1.0 µM, nH = 1.8; this concentration of inhibitor is significantly below its critical micelle concentration. Physically and kinetically glucokinase isolated from pig is similar to the enzyme isolated from rat. The porcine system provides a second source for isolation and further characterization of this important and unusual enzyme.
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    Molecular and cellular biochemistry 76 (1987), S. 45-54 
    ISSN: 1573-4919
    Keywords: DNA methyltransferase ; hemimethylated DNA ; kinetics ; affinity chromatography ; (rat liver)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract DNA substrate analogs were constructed from poly(dC-dG), M13, and XP12 DNA which do not contain a mixture of types of methylation sites. These were used to distinguish different kinetic mechanisms for maintenance and de novo methylation using a highly purified rat liver DNA (cytosine-5)-methyltransferase (DMase−) preparation. De novo methylation on single (ss) and double-stranded (ds) DNA was found to obey Michaelis-Menten kinetics while methylation of hemimethylated sites showed differences depending on size of the hemimethylated region. On long stretches analogous to maintenance methylation of newly replicated DNA, saturation could not be achieved and the kinetics showed non-ideal positive cooperative kinetics, while short stretches showed non-Michaelis-Menten kinetics and rapid saturation. Two types of DMase-DNA complexes could be distinguished by means of affinity chromatography on DNA-agarose matrices and in preincubation assays. The later complex, which is engaged in methyl group turnover, exhibited enhanced stability. The competitiveness of variously configured DNAs was found to parallel the stability of complex formation, e.g., ss, hemi- and ds DNA, respectively. In studies utilizing 5-bromodeoxyuridine, the thymine analog left the basic reaction mechanisms unchanged but increased the km and S0.5 while reducing the velocity of these reactions.
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    Potato research 28 (1985), S. 43-53 
    ISSN: 1871-4528
    Keywords: phosphate ; potassium ; nitrogen ; sprouting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Calzium förderte das Symptom einer subapikalen Spitzennekrose an wachsenden Keimen, verminderte als Sulfatsalz appliziert jedoch nicht die Konkurrenzwirkung zwischen Keimen für Reserven der Mutterknolle; die Keim-Trockengewichts-Akkumulation pro Auge war beispielweise durch eine höhere Zahl keimender Augen je Knolle noch stärker reduziert (Abb. 1 und 2). Die Konkurrenzwirkung reduzierte sich durch Zufuhr von exogenem NO3-N und wurde durch komplette Nährlösung verhindert. Die Bedeutung von N, P und K für die Konkurrenzminderung und eine optimierende Wachstumsverlängerung ergab sich aus dem selektiven Auslassen individueller Komponentender Lösung (Abb. 3 und 4). Beim Wachstum ergaben sich keine signifikanten Effekte wenn Mg, Fe und Spurenelemente aus dem Wachstumsmedium herausgenommen wurden. Dosis-Wirkungs-Kurven für Wachstum bei mehreren Calzium- und Stickstoff-Dosierungen zeigten, dass sich optimale Wachstumsraten ergaben wenn diese Elementen bei einer Konzentration von 10 mmol/l vorhanden waren. Signifikante Wachstumsreduktionen ergaben sich bei Senkung der NO3-N-Konzentration auf 1 mmol/l (Abb. 5). Gleiches ergab sich bei Calzium durch Senkung der Konzentration auf 0,1 mmol/l (Abb. 6 und 7).
    Abstract: Résumé Le calcium réduit l'apparition de nécroses subapicales de germes en croissance mais, apporté sous forme de sulfate, ne diminue pas la compétition entre les germes pour l'utilisation des réserves du tubercule mère. C'est-à-dire que l'accumulation de poids sec des germes par oeil était toujours sévèrement abaissée par une augmentation du nombre d'yeux par tubercule (fig. 1 et 2). La compétition est réduite par l'apport de NO3-N exogène et éliminée avec une solution nutritive complète. L'importance de N, P et K dans la diminution de la compétition et l'optimisation de la croissance en longueur est établie par l'omission individuelle et sélective de certains composants de la solution (fig. 3 et 4). Les absences de Mg, Fe et microéléments du milieu nutritif sont sans effet sur la croissance. Les courbes de réponse à la dose avec différents niveaux de calcium et d'azote montrent que les vitesses optimales de croissance sont établies quand ces éléments sont présents à la concentration de 10 mmol/l. Des réductions significatives de la croissance apparaissent lorsque la concentration en NO3-N est abaissée jusqu'à 1 mmol/l (fig. 5). En ce qui concerne le calcium, l'effet est marqué lorsque la concentration est réduite à 0,1 mmol/l (fig. 6 et 7).
    Notes: Summary Competition between sprouting eyes for mother tuber reserves (as determined by sprout dry-weight accumulation) was eliminated by incubating tubers in perlite watered with a complete nutrient solution. The importance of N, P and K in the alleviation of competition was established by the selective omission of individual components of the solution. However, within an eye the number of branch sprouts was reduced by an increase in the number of sprouting eyes per tuber and this response was not influenced by supplying exogenous mineral ions.
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    Potato research 25 (1982), S. 127-130 
    ISSN: 1871-4528
    Keywords: potato ; virus breeding ; resistance
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A clone ofSolanum berthaultii P.I. 265858 was not systemically infected when manually inoculated with isolates of PVX groups 1 to 3 but developed top-necrosis when grafted-inoculated, demonstrating it is hypersensitive. Plants sap- or graft-inoculated with an isolated of PVX group 4 or with PVXHB (a recently-discovered strain overcoming all reported sources of resistance to PVX) were infected systematically. The plants were extremely sensitive to these isolates, young leaves becoming necrotic and the plant dying within a few weeks and, whilst still alive, plants contained little virus and were a poor source of infection. These characteristics suggest that this clone could provide a means of breeding cultivars that would be protected against all known strains of PVX.
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    Potato research 32 (1989), S. 397-404 
    ISSN: 1871-4528
    Keywords: resistance ; inoculation of tuber slices ; infection of plants
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eye-bearing slices, cut from healthy potato tubers and placed between Parafilm membranes, were inoculated with potato leafroll virus (PLRV) byMyzus persicae. PLRV was detected by ELISA and by transmission tests in tuber slices and in plants grown from the slices of the susceptible cv. Désirée, but not in those of the resistant cv. Arkula. These results suggest that PLRV replication and transport within tuber phloem is controlled by specific mechanisms of resistance.M. persicae was also able to acquire and transmit PLRV toPl floridana from slices cut from tubers of infected plants. The aphids effectively transmitted PLRV from slices cut from the sprouting rose end but they failed to transmit it from slices cut from the heel end of tubers.
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  • 62
    ISSN: 1871-4528
    Keywords: resistance ; potato breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Über Unterschiede in der Vermehrung des Kartoffelzystennematoden auf anfälligen Kartoffelsorten wurde schon früher kurz berichtet. Versuche, die im Scottish Crop Research Institute durchgeführt wurden und Ergebnisse aus Prüfungen von Zuchtmaterial haben ergeben dass im Hinblick auf die Resistenz gegen den Kartoffelzystennematoden phänotypische und genotypische Unterschiede zwischen den Klonen bestehen. Hier wird über Untersuchungen repräsentativer Sorten derSolanum tuberosum ssp.tuberosum Gruppe in bezug auf Variationen ihrer Anfälligkeit gegenGlobodera pallida berichtet. Tabelle 1 zeigt eine Reihe von allgemein als anfällig geltenden Kartoffelsorten, die mitG. pallida (Pa 2/3) geprüft wurden. Es wird über fünf Versuche berichtet; in den ersten drei (1A, 1B und 1C) wird die Resistenz von Klonen die aus Knollen aufgewachsen waren, erfasst und in den anderen zwei Versuchen (2A und 2B) die Resistenz von Sämlingen die aus Kreuzungen mit anfälligen Sorten stammen. Im versuch 1A (1978) wurden Augenstecklinge von 9 Sorten in 8 Wiederholungen im Gewächshaus ausgepflanzt. Der Kompost John Innes Nr. 2 wurde mit 40 Eiern/g vonG. pallida (Pa 2/3) inokuliert. Nach 11 Wochen wurden die Zysten ausgezählt und als Prozent der Zysten auf Pentland Crown (% Anfälligkeit) ausgedrückt (siehe Tabelle 1, erste Reihe und statistische Verrechnung in Tabelle 2a) Im Versuch 1B (1982) wurden 25 Sorten in fünf Wiederholungen in geschlossenen Behältern mit 4 verschiedenen Inokulumdichten geprüft: 1500, 2000, 2500 und 3000 Eier Behälter. Sieben Wochen später wurden die Zysten gezählt und als % Anfälligkeit, basierend auf den durchschnittlichen Zystenzahlen der 4 Inokulumdichten (Tab. 1, statistische Verrechnung in Tabelle 2b) ausgedrückt. Im Versuch 1 C (1983) wurden 22 Sorten bei einer Inokulumdichte von 3500 Eiern/Behälter geprüft. Die Ergebnisse zeigt Tabelle 1 und die Statistik Tabelle 2c. In Tabelle 1 sind die Sorten in absteigender Reihenfolge angegeben, beginnend mit P. Javelin, die die höchste Zystenzahl aufwies. Fünf der in Tabelle 1 angegebenen 36 Sorten wurden in allen drei Prüfungen verwendet: P. Javelin, Désirée, M. Piper, Croft und P. Crown. Tabelle 3 zeigt die Varianzanalyse der fünf Sorten und für drei Jahre. Die in den Tabellen 2a, 2b und 2c aufgeführten Analysen zeigen dass signifikante Unterschiede (P〈0,001) im Hinblick auf die Zystenbildung zwischen den Sorten bestehen. Die Analyse in Tabelle 3 veranschaulicht dass die signifikanten Unterschiede in bezug auf die Zahl der gebildeten Zysten auf die Haupteinflüsse (Jahre, Sorten) zurükzuführen ist. Im ersten Sämlingstest (2A) wurde die Resistenz von Nachkommenschaften eines North Carolina 2-Kreuzungsprogrammes untersucht, bei dem elf gegenG. pallida resistente Klone mit sieben anfälligen gekreuzt wurden. Tabelle 4 zeigt die durchschnittlichen Zystenzahlen für die Nachkommenschaften der anfälligen Sorten und in Tabelle 5 ist die statistische Verrechnung aufgeführt. Die Verteilung des allgemeinen Kombinationsfähigkeitseffektes (Tab. 5) zeigt dass die anfälligen Eltern regelmässig, aber mit unterschiedlichem Ausmass zum generellen, inherenten Resistenzgrad gegen Kartoffelzystennematoden in der Nachkommenschaft beitragen. Im zweiten Sämlingstest (2B) wurde die Resistenz gegenG. pallida in 4 Nachkommenschaften anfälliger Eltern untersucht. Diese wurden in 5×5×4,5 cm Plastiktöpfen ‘Plant Pak’ in John Innes Nr. 2 Kompost, inokuliert mit 40 Eiern/g vonG. pallida, untersucht. 24 Einzelsämlinge wurden in jedem von 4 Blöcken randomisiert, Abb. 1 gibt die nach neun Wochen ausgezählten sichtbaren Zystenzahlen wieder. Das zeigt dass in den 4 Nachkommenschaften eine Abstufung der Anfälligkeit vorhanden ist. Die Ergebnisse der fünf Versuche zeigen dass zwischen den ursprünglich als anfällig angesehenen Sorten Unterschiede im Ausmass der Zystenproduktion bestehen. Diese Unterschiede stellen sowohl phänotypische als auch genotypische Variationen dar, die vorher beiSolanum tuberosum ssp.tuberosum nicht deutlich aufgezeigt waren. Diese Unterschiede können auf verschiedenen Faktoren des Phänotyps, ausser dem Resistenzmechanismus an sich, beruhen; im Zusammenhang mit einem Züchtungsprogramm ist aber am wichtigsten dass sie eine vererbbare Komponente haben, die zur Beschleunigung der phänotypischen Ausprägung der Resistenz beitragen kann.
    Abstract: Résumé Les variations de taux de multiplication des nématodes à kyste de la pomme de terre pour des variétés sensibles ont déjà été brièvement relatées. Des essais conduits au Scottish Crop Research Institute et les données de tests de routine dans le programme de sélection montrent que des différences phénotypiques et génotypiques existent entre clones, en ce qui concerne la résistance du nématode à kyste. Les études présentées concernent les variétés représentatives du groupeSolanum tuberosum ssp.tuberosum pour leur variation de sensibilité auGlobodera pallida. Des variétés généralement connues pour leur sensibilité auG. pallida (Pa2/3) sont expérimentées et mentionnées dans le tableau 1. Cinq essais sont réalisés. Les 3 premiers (1A, 1B et 1C) concernant la résistance des clones à partir des plantes issues de tubercules tandis que les deux autres (2A et 2B) se rapportent à la résistance de descendants issus de plantules provenant de croisements avec des variétés sensibles. Dans l'essai 1A (1978), des oeilletons de neuf variétés sont plantés en serre, à raison de 8 répétitions par variété. Le compost John Innes No 2 est inoculé avec 40 oeufs/g deG. pallida (Pa2/3). Les comptages de kystes après 11 semaines, exprimés en pourcentage du nombre de kystes sur Pentland Crown (% sensibilité) sont présentés dans la première colonne du tableau 1 et l'analyse statistique figure dans le tableau 2a. L'essai 1B (1982) comporte 25 variétés répétées cinq fois, en containers clos, et inoculées à 4 niveaux: 1500, 2000, 2500 et 3000 oeufs par container. Les comptages de kystes après 7 semaines sont présentés dans le tableau 1 en pourcentage de sensibilité sur la base des comptages moyens de kystes pour les 4 niveaux d'inoculum et l'analyse dans le tableau 2b. L'essai 1 C (1983) comporte 22 variétés, également en containers clos, maís avec un seul niveau d'inoculum: 3500 oeufs par container. Les résultats sont présentés dans le tableau 1 et l'analyse dans le tableau 2c. Les variétés présentées dans le tableau 1 sont classées par ordre décroissant avec comme première variété P. Javelin, qui produit le plus grand nombre de kystes. Pour les 36 variétés présentées dans le tableau 1, tous les test ont été réalisés sur cinq d'entre elles: P. Javelin, Désirée, M. Piper, Croft et P. Crown. L'arrachage de variance pour les 3 années et les cinq variétés est indiquée dans le tableau 3. Les analyses dans les tableaux 2a, 2b et 2c démontrent que des différences significatives (P〈0,001) existent entre les variétés, quant à la production de kystes. L'analyse dans le tableau 3 montre que la variation significative n'est expliquée que par les facteurs principaux (années et variétés), en ce qui concerne le nombre de kystes. Le premier test sur plantules met en évidence la résistance de la descendance par un programme de croisement North Carolina-2 entre 11 clônes résistants àG. pallida et 7 variétés sensibles. Un résumé des moyennes des kystes dans la descendance des variétés sensibles est indiqué dans le tableau 4 et l'analyse dans le tableau 5. Le part des effets combinés possibles, dans le tableau 5, montre que les parents sensibles contribuent de façon notable, mais à des degrés différents, aux niveaux de résistance propre au nématode pour chaque descendant. Le deuxième test sur plantules met en évidence la résistance àG. pallida pour quatre descendants de variétés sensibles. L'étude est faite dans des pots en plastique ‘plant pak’ de 5×5×4,5 cm remplis de compost John Innes No 2 inoculés avec 40 oeufs/g deG. pallida. 24 plantules individuelles sont placées au hasard dans chacun des quatre blocs. Les kistes visibles sont comptés après 9 semaines (figure 1); les résultats indiquent que différents niveaux de sensibilité existent pour les quatre descendants. Les résultats des cinq expériences démontrent qu'il y a des différences dans les niveaux de production de kystes pour des variétés prealablement classées comme étant d'égale sensibilité. Ces différences représentent des variations à la fois phénotypique et génotypique, au départ non clairement identifiées avecS. tuberosum ssp.tuberosum. Ces différences peuvent provenir de facteurs divers du phénotype autres que les mécanismes de résistance véritables, cependant il est important de considérer ce facteur héréditaire dans un programme de sélection ou il peut être utilisé pour accroître la résistance phénotypique.
    Notes: Summary Many cultivars of theSolanum tuberosum ssp.tuberosum group were investigated in a number of studies for their susceptibility toGlobodera pallida. Phenotypic and genotypic variation for this character is reported in material previously regarded as uniformly susceptible. The implications of these results are discussed in relation to potato breeding policy and nematological studies.
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    Potato research 24 (1981), S. 89-92 
    ISSN: 1871-4528
    Keywords: gangrene ; host specificity ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In experiments carried out over two years at two sites, a differential interaction between two potato varieties and two isolates ofP. exigua var.foveata was demonstrated in the cortical tissue.
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    Potato research 28 (1985), S. 27-33 
    ISSN: 1871-4528
    Keywords: infection experiments ; latent infection ; resistance ; symptom development ; ring rot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Wurzeln von gekeimten Saatknollen der Sorten Ostara, Laila, Kerrs Pink und Pimpernel wurden durch Tauchen in Suspensionen vonCorynebacterium sepedonicum inokuliert. Dies erbrachte einen beträchtlichen und signifikanten Ertragsrückgang, vor allem bei der Sorte Pimpernel (Tabelle 1); desweiteren zeigte sich eine signifikante Sorte/Infektion-Wechselwirkung. Inokulation ergab, mit Ausnahme von Laila, eine signifikante Senkung der durchschnittlichen Knollenzahl (Tabelle 2); am grössten war der Rückgang bei Kerrs Pink, während das durchschnittliche Knollengewicht am meisten zurückging bei Pimpernel (Tabelle 3). Der Ertragsrückgang bei Laila erfolgte durch Reduktion des durchschnittlichen Knollengewichtes, bei den anderen Sorten jedoch durch Rückgang der durchschnittlichen Knollenzahl. Diese Beobachtung lässt darauf schliessen dass die Entwicklung der Infektion bei Laila nach der Knollen-Initiierung einsetzte, während sie bei den anderen Sorten schon früher einsetzte und somit die Knollenzahl beeinflusste. Im Gegensatz zu den anderen Sorten zeigten einige Tochterknollen von Laila äussere Symptome, in Verbindung mit starker Fäule, während in der Entwicklung interner Symptome nur geringe Unterschiede zwischen den Sorten gefunden wurden (Tabelle 4). Dennoch waren die Konzentrationen vonC. sepedonicum in den meisten symptomlosen Tochterknollen inokulierter Pflanzen hoch (Tabelle 4). Die Ergebnisse zeigen dass die Sorte Laila gegen eineC. sepedonicum-Infektion resistenter als die anderen geprüften Sorten ist, dass jedoch hohe Konzentrationen des Erregers in symptomlosen Knollen von inokulierten Pflanzen gegen eine Verwendung bei der Züchtung sprechen.
    Abstract: Résumé Des racines de tubercules de semence germés (variétés Ostara, Laila, Kerrs Pink et Pimpernel) sont inoculées par immersion dans des suspensions deCorynebacterium sepedonicum. Cela provoque une diminution conéquente et significative du rendement, en particulier pour la variété Pimpernel (tableau 1), et il existe une interaction significative variété/infection. L'inoculation diminue significativement le nombre moyen de tubercules (tableau 2) sauf pour la variété Laila; la diminution est la plus importante pour la variété Kerrs Pink, tandis que le poids moyen de tubercules diminue le plus pour la variété Pimpernel (tableau 3). La diminution du rendement pour la variété Laila est provoquée par une réduction du poids de tubercules. Cette observation suggère que le développement de l'infection pour la variété Laila débute après l'initiation de tubérisation, alors que pour les autres variétés, elle commence plus tôt et de ce fait influence le nombre de tubercules. Peu de tubercules fils de la variété Laila montrent des symptômes externes associés à une pourriture importante en comparaison avec les autres variétés, alors que de petites différences s'observent entre toutes les variétés au niveau du développement de symptômes internes (tableau 4). Les concentrations deC. sepedonicum sont cependant élevées dans la plupart des tubercules fils ne présentant pas de symptômes et provenant de plantes inoculées (tableau 4). Les résultats montrent que la variété Laila est plus résistante à l'infection deC. sepedonicum que les autres variétés testées, mais les fortes concentrations du pathogène dans les tubercules sans symptôme provenant de plantes inoculées empêchent son utilisation en multiplication.
    Notes: Summary Inoculating the roots of potato cvs Ostara, Laila, Kerrs Pink, and Pimpernel withCorynebacterium sepedonicum caused severe rotting of tubers and between 12 and 51 % decrease in yield. There was a significant cultivar/infection interaction. The numbers of tubers decreased significantly except for cv. Laila, which also showed little rotting of tubers, and the average tuber weight decreased most in cv. Pimpernel. The concentration ofC. sepedonicum was high in most inoculated tubers including those not showing symptoms.
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    Potato research 23 (1980), S. 371-375 
    ISSN: 1871-4528
    Keywords: nitrogen ; phosphorus ; potassium ; calcium ; sodium ; nitrate ; sulphate ; micronutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The specific gravity and dry matter content of 193 tuber samples (cultivars: Arran Banner, Spunta, Up-to-Date, Cara) from crops grown at Kokkinochoria, the major potato growing area of Cyprus, were related to each other as follows: Dry matter (%)=−269.59+268.24×specific gravity. This regression accounted for 82.4% of the variation; the fiducial limits (P〈0.05) for single determinations of specific gravity were±1.54 percentage units. The mineral contents of the tubers were similar to those reported in other countries.
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    Potato research 30 (1987), S. 1-8 
    ISSN: 1871-4528
    Keywords: resistance ; latent infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Es wurden 13 Kartoffelsorten auf das Vorhandensein vonPhoma exigua var.foveata in Stengeln und grünen Blättern untersucht. Pflanzknollen, die nach künstlicher Infektion faulten, wurden im Feld ausgepflanzt; nach 5, 12 und 17 Wochen wurden pro Sorte vier Stengel mit Blättern nach dem Zufallsprinzip ausgewählt, wobei jeder Stengel eine Pflanze repräsentierte. Die Stengel wurden gewaschen, getrocknet und in 5 cm-Segmente geteilt. Nach Oberflächensterilisation wurden die Segmente und die Blattschnitte in Petrischalen auf ein selektives Agarmedium gebracht, das zur Förderung der Pyknidienentwicklung Paraquat enthielt.P. exigua var.foveata wurde auf Malzextraktagar bestimmt, der Thiophanatmethyl und Chloramphenicol enthielt. Die Sorten reagierten unterschiedlich auf die Infektion, wie an der Anzahl der Schnitte, die das Pathogen lieferten, zu ersehen ist. Die Nachweishäufigkeit war am niedrigsten bei der ersten und am höchsten bei der letzten Probenahme (Tab. 2). Die mittleren Prozentwerte varierten von 13% bis 36%, die Reihenfolge war zwischen den Jahren ähnlich (Tab. 1). Das Verteilungsmuster der Schnitte, die das Pathogen lieferten, war unregelmässig; es wurde überall in Stengelschnitten und Blättchen vom oberirdischen Trieb nachgewiesen und in nur wenigen Fällen auch in Stengelsegmenten unterhalb der Bodenoberfläche (Tab. 3). Die Werte zeigen, dass die Anfälligkeit der Sorten zur symptomlosen Invasion der grünen Triebe differiert. Inwieweit in dieser Phase des Lebenszyklus des Pilzes eine Resistenzauslese lohnend ist, hängt von der möglichen Bedeutung des Stengelinokulums als Quelle für die Infektion der Knollennachkommenschaft ab. Es war mit dieser Untersuchung nicht beabsichtigt, Fragen, die sich auf die Ausbreitung des Pilzes beziehen, zu beantworten; ein besseres Verständnis der Biologie dieses Krankheitserregers ist aber entscheidend zur rationalen Anwendung der Ergebnisse in der Pflanzenzüchtung.
    Abstract: Résumé La présence dePhoma exigua var.foveata dans les tiges et les feuilles vertes est étudiée sur treize variétés de pommes de terre. Des tubercules de semence pourris après contamination artificielle, sont plantés au champ. Après 5, 12 et 17 semaines, 4 tiges avec les feuilles de chaque variété sont prélevées au hasard, chaque tige représentant une plante. Les tiges sont lavées, séchées et coupées en segments de 5 cm. Après une stérilisation de surface les segments et des sections de folioles sont placés en boites de pétri sur un milieu sélectif à base d'agar contenant du paraquat afin de favoriser le développement des pycnides.Phoma exigua var.foveata est identifié sur malt agar contenant du thiophanate-méthyl et chloramphenicol. Les variétés répondent différemment à l'infection, comme le montre le nombre de sections hébergeant le pathogène. La fréquence de détection est la plus faible à la première date d'échantillonnage et la plus élevée à la dernière (tableau 2). Le pourcentage moyen varie entre 13 et 36%, le classement est similaire entre les années (tableau 1). La distribution du pathogène hébergé par les échantillons est irrégulière. Il est détecté sur des sections de tiges et des folioles au dessus du sol et dans quelques cas sur des segments de tiges en dessous de la surface du sol (tableau 3). Les données montrent que la sensibilité des variétés à l'infection des parties aériennes est variable. L'intérêt d'une sélection à la résistance pour cette phase du cycle du champignon dépend de l'importance potentielle de l'inoculum sur tige en temps que source de contamination des tubercules-fils. Cette étude n'a pas pour but d'expliquer la dissémination du champignon, mais une meilleure connaissance de la biologie du pathogène est fondamentale pour une application rationnelle des résultats de la multiplication variétale.
    Notes: Summary Thirteen cultivars were tested for presence ofPhoma exigua var.foveata in stems and green leaves. The frequency of segments yielding the pathogen increased with time during the growing season and varied between cultivars from 13 to 36% and their distribution pattern was irregular. There were significant differences between cultivars to this symptomless invasion of the green shoots. The value of such cultivar differences depends on the interpretation of the importance of stem inoculum in carrying the disease to the next tuber generation.
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    Investigational new drugs 7 (1989), S. 27-36 
    ISSN: 1573-0646
    Keywords: kinetics ; fluorouracil ; bolics ; administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Thymidylate synthase (TS) is the enzyme target of 5-fluorouracil (FUra) that recent laboratory and clinical studies with folinic acid (calcium leucovorin) suggest may mediate important antitumor cytotoxicity. Measurement in carcinoma tissue of parameters related to TS inhibition by 5-fluorodeoxyuridylate (FdUMP), by analogy to hormone receptor analysis, should be useful to determine which patients should receive fluoropyrimidine drug therapy and to evaluate folinic acid requirements. Folinic acid is metabolized to 5,10-methylenetetrahydropteroylglutamine (CH2FH4), which must be present in large excess to effect desired levels of maximal inhibition of TS, by promoting formation and stabilization of TS-FdUMP-CH2FH4 ternary complexes. In patients with metastatic disease, serial biopsies of tumor and normal tissues for studies of pharmacodynamic responses to test-dose FUra or folinic acid are shown to be easily added to routine intraoperative management. A suitable methodologic approach is described and examples given of assays of free TS, FdUMP, dUMP, and CH2FH4 levels after FUra or folinic acid, that may be useful in future studies aimed at improving the cost-effectiveness of FUra-folinic acid combinations.
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    ISSN: 1573-0646
    Keywords: heterogeneity ; polyamines ; cell killing ; kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The effects of α-difluoromethylornithine (DFMO) on survival, cell kinetics and polyamine levels were studied on two clones of human astrocytoma in vitro. The survival responses were dose and time dependent; and treatments with DFMO which lasted for 72 h resulted in heterogeneous responses with one clone being up to 6 times more sensitive than the other. Shorter treatments produced more uniform killing in the clones. A continuous exposure of the cells to 5 mM DFMO resulted in a rapid decrease in putrescine values in both clones, followed by decreases in the spermidine levels. These effects were closely followed by 148% to 170% increases in cell population doubling times, and a lowering of saturation densities. No clear correlations could be established among baseline polyamine levels and cell kinetics or survival responses to DFMO treatments.
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    Bulletin of experimental biology and medicine 101 (1986), S. 365-366 
    ISSN: 1573-8221
    Keywords: hematopoietic stem cells ; CFU-S ; self-maintenance ; kinetics
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    Bulletin of experimental biology and medicine 102 (1986), S. 1269-1272 
    ISSN: 1573-8221
    Keywords: Daphnia ; Nag vibrios ; intestinal epithelium ; resistance
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    Bulletin of experimental biology and medicine 102 (1986), S. 1293-1296 
    ISSN: 1573-8221
    Keywords: liver ; lysosomotropism ; resistance ; morphology ; stereometry
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    Bulletin of experimental biology and medicine 103 (1987), S. 660-662 
    ISSN: 1573-8221
    Keywords: hydrogenated phenazepam analog ; metabolism ; kinetics ; excretion ; differences
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    Bulletin of experimental biology and medicine 103 (1987), S. 592-594 
    ISSN: 1573-8221
    Keywords: conditioned reflex ; adaptation to mountain climate ; emotional-painful stress ; amnesia ; resistance
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    Bulletin of experimental biology and medicine 91 (1981), S. 819-822 
    ISSN: 1573-8221
    Keywords: colchicine ; resistance ; membrane permeability ; heredity
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    Bulletin of experimental biology and medicine 94 (1982), S. 1720-1722 
    ISSN: 1573-8221
    Keywords: susceptibility ; resistance ; genetic control
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    Bulletin of experimental biology and medicine 95 (1983), S. 151-153 
    ISSN: 1573-8221
    Keywords: antigen-antibody reaction ; kinetics ; laser ; scattering of light
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    Bulletin of experimental biology and medicine 95 (1983), S. 712-714 
    ISSN: 1573-8221
    Keywords: erythrocytes ; resistance ; heat ; scattering of light
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    Bulletin of experimental biology and medicine 95 (1983), S. 738-741 
    ISSN: 1573-8221
    Keywords: experimental epilepsy ; hypoxia ; resistance
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    ISSN: 1573-8221
    Keywords: emotional stress ; resistance ; perifornical region of the hypothalamus ; acetylcholinesterase ; cholineacetyltransferase
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    Bulletin of experimental biology and medicine 89 (1980), S. 124-126 
    ISSN: 1573-8221
    Keywords: lymphocytes ; resistance ; schizophrenia
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    Topics: Biology , Medicine
    Notes: Abstract Investigation of the osmotic resistance of peripheral blood lymphocytes from healthy blood donors and patients with schizophrenia revealed the existence under normal conditions of lymphocytes which differ sharply from one another in the criterion of resistance to osmotic shock: 20% of lymphocytes have low resistance and 80% high resistance. Lymphocytes with low resistance from healthy donors were shown to have increased adhesive properties. In 60% of schizophrenics there were virtually no lymphocytes with low resistance. The highly resistant lymphocytes of such patients include some characterized by abnormal resistance.
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  • 81
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    Bulletin of experimental biology and medicine 97 (1984), S. 323-326 
    ISSN: 1573-8221
    Keywords: resistance ; peritoneal exudate ; tumor
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  • 82
    ISSN: 1573-8221
    Keywords: emotional stress ; resistance ; acetylcholinesterase ; choline acetyltransferase ; butylrylcholinesterase
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  • 83
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    Bulletin of experimental biology and medicine 108 (1989), S. 1541-1545 
    ISSN: 1573-8221
    Keywords: stress ; adaptation ; resting potential ; resistance
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  • 84
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    European journal of plant pathology 88 (1982), S. 163-170 
    ISSN: 1573-8469
    Keywords: TMV strains ; pathogenicity ; resistance ; hypersensitivity ; susceptibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Om verschillen in pathogeniteit tussen twee in Nederland voorkomende paprikastammen van het TMV nader vast te stellen, werd een aantalCapsicum-herkomsten, waaronder negen soorten, op resistentie getoetst. Hierbij werden de representatieve paprika-isolaten P 11 en P 8 vergeleken met de uit tomaat afkomstige isolaten MA en SPS als vertegenwoordigers van respectievelijk de tabaks- en tomatestam van het TMV. Bij het beoordelen van de symptomen duidden lokale, necrotische vlekken en afvallen van geïnoculeerde bladeren op resistentie, systemische necrosen of mozaïeksymptomen op vatbaarheid. In deze symptomen kwamen tussen de gebruikte stammen verschillen in virulentie tot uitdrukking. Er werden echter vooral verschillen in agressiviteit waargenomen met betrekking tot zowel afzonderlijke, voor resistentie uitsplitsende,Capsicum-herkomsten als het totale aantal getoetste herkomsten. Van de ruim 73 herkomsten waren er 58 resistent tegen MA en SPS, 31 daarvan tegen P 11, maar slechts vijf daarvan tegen P 8. Deze resistentie tegen P 8 werd gevonden inC. chinense.
    Notes: Abstract A number ofCapsicum accessions including nine species were tested for resistance to TMV based on hypersensitivity. The tobacco strain MA and the tomato strain SPS, which were both isolated from tomato, and two pathogenically distinct pepper strains P 11 and P 8, were used. Of the 73Capsicum accessions tested 58 were resistant to MA and SPS, 31 were resistant to P 11 and five were resistant to P 8.
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  • 85
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    Plant and soil 113 (1989), S. 121-124 
    ISSN: 1573-5036
    Keywords: CAT scanning ; drawdown ; plant roots ; resistance ; water uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using the technique of Computer Assisted Tomography applied to gamma ray attenuation measurement of soil water content, it has been shown that the assumption of uniform absorption of soil water along a plant root is clearly erroneous and that drawdown distance is a function of time. The results suggest that the plant sequentially removes water from the top to the bottom of the root as soil hydraulic resistance becomes a major limiting factor in the upper layers, even at the high soil water potential (−0.30 MPa) used.
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  • 86
    ISSN: 1573-5036
    Keywords: carbon ; erosion ; land clearing ; nitrogen ; noncalcic brown soils ; phosphorus ; spatial variability ; xerosols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several transects of topsoil samples were taken immediately after land clearing and one year later from a savannah soil in the semiarid NE of Brazil. Natural spatial variability of key fertility indicators (C, N, P) was large with coefficients of variation 〉50%. This variability was related to heterogeneity of the soil parent material, and to relative slope position which affected deposition and removal of erodible materials. The distribution of gravel and different particle size fractions was an indicator of the variability as related to soil formation and erosional resorting. One year after the site was cleared and planted to trees, the decrease in C, N and resin-extractable P was in the same range as the initial spatial variability. Treatment effects were therefore difficult to observe but became more obvious when regression analysis on soil textural components was used to reduce data variability.
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  • 87
    ISSN: 1573-5036
    Keywords: actinorhizal ; Ceanothus ; Frankia ; nitrogen ; propagation ; inoculation ; nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rooted cuttings ofCeanothus griseus varhorizontalis were irrigated with 0, 10, 20, 50, 75 or 100ppm nitrogen as NH4NO3 for eight weeks prior to inoculation with infectiveFrankia. After inoculation, half of the plants for each treatment nitrogen level continued to be irrigated with the preconditioning nitrogen level and half were given no more supplemental nitrogen. For plants continuously receiving nitrogen, nodule initiation (nodule number) was inversely correlated with increasing supplemental nitrogen levels, and suppressed above 50 ppm N. Leaf nitrogen above 2% in continuous-N plants correlated with greatly reduced or suppressed nodulation. Plants maintained after inoculation without supplemental nitrogen showed influence of the prior nitrogen treatment on nodulation. Preconditioning at 50 ppm and above greatly reduced the number of nodules formed. The evidence suggests that stored internal nitrogen can regulate nodulation. Plant biomass accumulated maximally when nodulation was suppressed, at 75 and 100 ppm supplemental N applied continuously. Internode elongation during the nodulation period occurred only on nodulated plants, or in the presence of supplemental N (10 ppm and above).
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  • 88
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    European journal of plant pathology 95 (1989), S. 343-356 
    ISSN: 1573-8469
    Keywords: centre of virus origin ; hypersensitivity-associated resistance ; immunity ; resistance ; resistance sources ; sensitivity ; test plants ; tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Na inoculatie van een grote collectieNicotiana-soorten met 14 isolaten van de aardappelvirussen A (PVA), X (PVX) en Y (PVY) en tabaksmozaïekvirus (TMV), konden de secties of sectiedelen van het genus op basis van de gemiddelde reactie van hun soorten in vijf groepen worden verdeeld. Soorten uit Australische woestijngebieden en taxonomisch behorend tot de sectieSuaveolentes (subgenusPetunioides) bleken het meest gevoelig en het minst resistent, terwijl de sectiesPaniculatae (subgenusRustica),Tomentosae (Tabacum) enNoctiflorae (Petunioides) het minst gevoelig en het meest resistent waren. Van de collectienummers van de laatstgenoemde secties bleek 61% resistentie tegen minstens twee van de virussen te bezitten. De meest resistente soorten hebben hun verspreidingsgebied vooral in het centrale deel van het Andesgebergte (het zuidelijk deel van Peru, Bolivia en noord-westelijk Argentinië). Mogelijk is dit het ontstaansgebied van deze virussen. De einge andere resistente soort wasN. africana (Suaveolentes) uit zuid-westelijk Afrika. De meest gevoelige Amerikaanse secties, te wetenGenuinae (Tabacum) enTrigonophyllae, Alatae, Acuminatae enBigelovianae (Petunioides), waren gemiddeld gevoeliger danSuaveolentes-soorten die niet uit de Australische woestijnen afkomstig zijn. Het resterende deel van het genus, bestaande uit de Amerikaanse sectiesThyrsiflorae enRusticae (Rustica) enUndulatae, Repandae enNudicaules (Petunioides), stond met betrekking tot gevoeligheid en resistentie tussen laatstgenoemd deel van de sectieSuaveolentes en de groep resistente secties in, maar vertoonde in hoge mate tolerantie voor PVA, PVX en PVY en met overgevoeligheid samengaande resistentie voor TMV. Uit de resultaten blijkt dat de reacties van het genusNicotiana op virussen vooral geografisch bepaald zijn en in mindere mate taxonomisch.
    Notes: Abstract When testing the response of species of the genusNicotiana to 14 isolates of potato viruses A (PVA), X (PVX) and Y (PVY) and tobacco mosaic virus (TMV), sections and section parts of the genus could be divided into five groups according to the overall reaction of their species. Species from arid regions of australia and belonging to the sectionSuaveolentes (subgenusPetunioides) were most sensitive and least resistant, whereas the sectionsPaniculatae (subgenusRustica),Tomentosae (Tabacum) andNoctiflorae (Petunioides) appeared least sensitive and most resistant. Sixty-one percent of the accessions of the latter sections proved resistant to at least two of the viruses. The most resistant species have their main geographical distribution in the central Andes (southern Peru, Bolivia and north-western Argentina), where the viruses may have originated. One other resistant species wasN. africana (Suaveolentes) indigenous to south-western Africa. The most sensitive American sections, viz.Genuinae (Tabacum) andTrigonophyllae, Alatae, Acuminatae andBigelovianae (Petunioides), were generally more sensitive than species of theSuaveolentes section from outside the arid regions of Australia. The remaining part of the genus, viz. the American sectionsThyrsiflorae andRusticae (Rustica) andUndulatae, Repandea andNudicaules (Petunioides) was intermediate between the latter group ofSuaveolentes species and the resistant group of sections with regard to sensitivity and resistance, but had a high rate of tolerance to PVA, PVX and PVY and of hypersensitivity-associated resistance to TMV. The results indicate that the viral respons in the genusNicotiana is mainly determined geographically and to a lesser extent taxonomically.
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  • 89
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    European journal of plant pathology 89 (1983), S. 275-281 
    ISSN: 1573-8469
    Keywords: interspecific and intraspecific hybrids ; grafting experiments ; N gene ; resistance ; temperature effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Screening for the pathogenesis-related (b) protein patterns of 11Nicotiana species and 30N. tabacum varieties has revealed both inter- and intraspecific variability and 7 different b-proteins (b0, b1, b1′, b1″, b2, b3 and b4) have been clearly defined. Their genetic determinants are sexually transmitted independently of theN gene conferring resistance to TMV, and a monogenic inheritance has been demonstrated for one of them (b1′). Grafting experiments have revealed the existence of a species-aspecific ‘mobile compound’ responsible for the expression of the b-protein genes, the production of which is probably under the control of theN gene. Among the 5 intraspecific and 6 interspecific hybrids studied, one of them, theN. glutinosa x N. debneyi together with its amphidiploid, synthesizes b-protein (b1″) in a constituve way and possesses a high level of resistance to necrosis-inducing viruses. The amphidiploid is able to transfer these two properties to otherNicotianae not only by crossing but also by grafting; it therefore appears to permanently synthesize the ‘mobile compounds’. Furthermore, the hypersensitive reaction to TMV in these hybrids is only completely broken down at 35 °C, whereas this normally occurs at 30 °C in plants with theN gene.
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  • 90
    ISSN: 1573-9104
    Keywords: barley ; Triticeae ; grain ; amino acid composition ; nitrogen ; chemical score
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Barley grains (9 samples from 7 cultivars) with nitrogen contents (N) ranging from 1.45 to 4.01% of dry matter were analysed for their amino acid (AA) composition with high accuracy from six different hydrolysates per sample. AA levels in grain increased as linear functions ofN with correlation coefficients close to unity. A comparison with literature data confirmed that the AA composition of any grain sample of normal barley can be predicted from itsN for all phenotypes and genotypes. AAs in grain protein changed as hyperbolic functions ofN which increased for Phe, Pro and Glx but more or less strongly decreased for the other AAs. By plotting AA scores againstN, barley proteins were shown to be always richer than wheat and rye in Val and Phe + Tyr; sometimes richer than both other species forN〈2 (Lys); 2.2 (Leu and Ile); 3.4 (Thr); sometimes intermediate to wheat and rye above the latterN values. They were also intermediate in sulphur AAs forN〈1.9 and drastically poorer forN〉1.9. However, they were richer than both other species in Trp forN〉1.6. The hyperbolic variations of non-protein nitrogen and nitrogen-to-protein conversion factors were determined as a function ofN and also compared with those of wheat and rye.
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  • 91
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    Plant foods for human nutrition 34 (1984), S. 221-228 
    ISSN: 1573-9104
    Keywords: Lupinus albus ; L. angustifolius ; lupine ; nitrogen ; lipids ; fatty acids ; seed development
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Developing seeds of lupine cultivars Kali, Neuland, Reuscher and Unicrop, grown under field conditions, were sampled at different stages of maturity and analysed for total nitrogen, crude fat and fatty acid composition. Nitrogen and lipid deposition occurred between 30 and 60 days after anthesis coinciding with the stage of maximal dry weight increase of the developing seed. The rate and duration of dry matter, nitrogen and crude fat accumulation was cultivar dependent. Percent of total saturated fatty acid decreased with increasing seed development.
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  • 92
    ISSN: 1573-5036
    Keywords: added nitrogen interaction ; green manure ; 15N ; N loss ; neem ; nitrate ; nitrogen ; Oryza sativa L. ; Vigna unguiculata (L.) Walp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Little is known about whether the high N losses from inorganic N fertilizers applied to lowland rice (Oryza sativa L.) are affected by the combined use of either legume green manure or residue with N fertilizers. Field experiments were conducted in 1986 and 1987 on an Andaqueptic Haplaquoll in the Philippines to determine the effect of cowpea [Vigna unguiculata (L.) Walp.] cropping systems before rice on the fate and use efficiency of15N-labeled, urea and neem cake (Azadirachta indica Juss.) coated urea (NCU) applied to the subsequent transplanted lowland rice crop. The pre-rice cropping systems were fallow, cowpea incorporated at the flowering stage as a green manure, and cowpea grown to maturity with subsequent incorporation of residue remaining after grain and pod removal. The incorporated green manure contained 70 and 67 kg N ha−1 in 1986 and 1987, respectively. The incorporated residue contained 54 and 49 kg N ha−1 in 1986 and 1987, respectively. The unrecovered15N in the15N balances for 58 kg N ha−1 applied as urea or NCU ranged from 23 to 34% but was not affected by pre-rice cropping system. The partial pressure of ammoniapNH3, and floodwater (nitrate + nitrite)-N following application of 29 kg N ha−1 as urea or NCU to 0.05-m-deep floodwater at 14 days after transplanting was not affected by pre-rice cropping system. In plots not fertilized with urea or NCU, green manure contributed an extra 12 and 26 kg N ha−1, to mature rice plants in 1986 and 1987, respectively. The corresponding contributions from residue were 19 and 23 kg N ha−1, respectively. Coating urea with 0.2g neem cake per g urea had no effect on loss of urea-N in either year; however, it significantly increased grain yield (0.4 Mg ha−1) and total plant N (11 kg ha−1) in 1987 but not in 1986.
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  • 93
    ISSN: 1573-5036
    Keywords: decomposition ; green manure ; litterbag ; nitrogen ; paddy rice ; Sesbania sesban ; Sri Lanka
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sesbania sesban was evaluated as green manure crop for lowland rice in the Dry Zone of Sri Lanka. The legume was grown during a fallow period before lowland rice (Oryza sativa) and ploughed under just before transplanting. Weight loss and nitrogen content in litterbags containing leaves, stems and roots of the legume were monitored. Comparisons were made between rice yields from 20 m2 plots after green manuring in combination with different nitrogen fertilizer levels (0, 2.4, 4.8 and 7.2 gm−2) and nitrogen fertilizer (9.6 gm−2) alone. Above-ground biomass ofS. sesban was 440 gm−2 (dry wt) when ploughed under after 84 days growth. N-content in leaves, stems and roots was 3.76%, 0.41% and 0.73%, respectively. This gave a N-input fromS. sesban of 9.2 gm−2 (8.3 g from above-ground parts and 0.9 g from roots). The corresponding K and P inputs were 7.3 and 0.6 gm−2 respectively. The nitrogen rich leaves, which contained 88% of the nitrogen in the above-ground parts, decomposed and released its nitrogen much more rapidly than the stems and roots. After only four days the leaves had released 5.3 g Nm−2 and after 14 days they had released 6.4 g Nm−2. The highest rice yield (505 gm−2) was obtained usingS. sesban and 4.8 gm−2 of N-fertilizer. The yields with only N-fertilizer or onlyS. sesban were 442 gm−2 and 396 gm−2, respectively. Due to the rapid decomposition of the nitrogen rich leaves,S. sesban did not behave as a slow release fertilizer. Thus, it is not necessary to apply nitrogen fertilizers as a basal dose.
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  • 94
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    Plant and soil 116 (1989), S. 77-84 
    ISSN: 1573-5036
    Keywords: alfalfa ; amino acids ; ammonium ; Glycine max (L.) Merr. ; leachates ; lucerne ; Medicago sativa L. ; nitrogen ; rhizosphere ; root exudates ; soyabean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An enclosed root chamber containing sterile sand medium was used to study net nitrogen (N) release from actively growing root systems of ‘Saranac’ alfalfa (Medicago sativa L.) and ‘Fiskeby V’ soybean (Glycine max L. Merr.). Plants were inoculated with a rhizobial strain appropriate to each host, irrigated with N-free nutrient solution, and grown either to 85 or to 173 d after germination (alfalfa) or to physiological maturity (soybean). Alfalfa released 4.5% of symbiotically-fixed plant N into the root zone over its growth period; soybean released 10.4% of plant N. Root zone leachates were analyzed for total N and for amino acid and ammonium content. Significant ammonium-N release occurred from the alfalfa but not the soybean root system; little amino-N was released by root systems of either species. Shoot harvest and water deficit caused increased release of N from alfalfa roots. The results provide evidence that alfalfa and soybean released significant proportions of their N into the root zone, and indicate that while substantial ammonium-N was released from alfalfa roots, passive leakage of amino-N was not a primary mechanism for N release from root systems of either species.
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  • 95
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    Plant and soil 106 (1988), S. 35-41 
    ISSN: 1573-5036
    Keywords: carbon ; crop residue ; mineralization ; nitrogen ; organic matter ; sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mineralization of C, N, and S from residues of three different crop species (wheat, lentil, and rape) grown under diverse nutritional regimes was measured over a 12-week incubation period under controlled conditions. The rate of decomposition, as measured by CO2 evolution, varied considerably among treatments and appeared to be controlled almost entirely by N content of the residue (R2=0.98). Similarly, N mineralization was strongly tied to N concentration. The critical N concentration, below which significant immobilization of N occurred, declined over time, ranging from 1.9% at day 14 to 1.1% at day 84. Mineralization of S was positively correlated with initial S concentration (R2=0.95) and negatively related to N concentration, apparently because of a dilution effect. The results demonstrate that decomposition and N and S mineralization of crop residues, under conditions prevalent in the experiment, are primarily a function of their nutrient concentrations rather than biochemial composition related to crop species. As a result, it should be possible to enhance rate of residue decomposition, increase quantities of N and S mineralized, and avert detrimental immobilization losses in the following year by governing the nutritional regime under which the crop is grown.
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  • 96
    ISSN: 1573-5036
    Keywords: decomposition ; lignin ; litter ; nitrogen ; sub-tropical-forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of the initial lignin and nitrogen contents of the leaves of five tree species, on their decomposition dynamics, was studied in the sub-tropical forest ecosystem existing at Shiroy hills. The decomposition dynamics of litter materials are described by inverse linear relationships between the percentage of the original biomass remaining and the nitrogen concentration in the residual material. Initial lignin and nitrogen were highly correlated with remaining biomass (r=0.94 and 0.77). The rate constants (K), for the annual leaf mass loss, ranged from −0.18 to −0.56. The values for initial lignin (%), initial nitrogen (%), the ratio between initial lignin, initial nitrogen and the annual decomposition rate constants were compared with similar results from other studies in various climatic zones of the world.
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  • 97
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    Plant and soil 102 (1987), S. 185-191 
    ISSN: 1573-5036
    Keywords: green manure ; leaching ; loam ; nitrogen ; nitrogen budget ; N-15 ; subterranean clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The leaching of subterranean clover-derived N (15N) was investigated in a laboratory and a field experiment. In both experiments 30 cm i.d. ×50cm soil columns were used. In the laboratory experiment the clover material was buried in the soil in mesh bags, and leaching of clover-derived N was compared to leaching of added NH 4 + −N and NO 3 − −N over a period of 75 days at 20°C. During that time 75% of the clover-N was released from the mesh bags and 17% of the clover-N, 50% of the NH 4 + −N and 70% of the NO 3 − −N was leached through the soil column. In the field experiment 6 lysimeters and 7 control microplots were constructed. The clover material was buried in soil (to the soil of two control microplots within mesh bags) in October. During one year 2% of the added clover-N was leached. This was despite a release of 65% of the N from the mesh bag contents and despite a 26% loss of the clover-derived N in total from the controls.
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  • 98
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    Plant and soil 103 (1987), S. 205-212 
    ISSN: 1573-5036
    Keywords: ammonia volatilization ; calcareous soils ; CEC ; nitrogen ; nitrogen losses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A quantitative model of ammonia volatilization from the calcareous soil uppermost 1-cm layer was developed and tested. The model accounts for the following processes: ammonium-ammonia equilibration in the soil solution, cation exchange between calcium and ammonium which results in ammonium distribution between soil liquid and solid phases, nitrification of dissolved ammonium, distribution of ammonia between liquid and gaseous phases and diffusion of gaseous ammonia in the soil air. The combined effect of various characteristics such as soil pH, cation exchange capacity, water capacity and nitrification rate on ammonia losses from various soil types have been studied. The model was validated against experimental results of ammonia losses from different soils for its use as a predicting tool. The model shows that most of ammonia losses can be explained by the interactive effect of high soil pH and low cation exchange capacity. Computations show increased ammonia volatilization with decreasing soil water capacity. Increasing fertilizer application rate has a small effect on percentage of ammonia losses. Increased nitrification rate and shorter “lag” period of nitrification reduce ammonia losses considerably. Good agreement was obtained between model calculations and experimental results of ammonia volatilization from 13 soils.
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  • 99
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    Plant and soil 105 (1988), S. 105-111 
    ISSN: 1573-5036
    Keywords: chronosequence ; desert ; ion-exchange resins ; mineralization ; nitrogen ; nutrient availability ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Anin situ resin bag technique was used to measure the relative availabilities of N and P along a chronosequence of soils in southern New Mexico, and was compared to two more common indices of nutrient availability. Accumulations of N and P during 10-week intervals over an 18 month period were separable into wet season (September–January) and dry season (February–August) groups, with wet season values significantly greater than dry season values. Only accumulations during the wet season showed significant differences among sites, thus stressing the role of field water regime in interpreting resin accumulation results. Total mineral N (NO3+NH4) sorbed by resins was significantly correlated to laboratory N mineralization rates. Although accumulation patterns of N and P were similar to patterns of %N and %P in shrub species growing along the chronosequence, these similarities were not statistically significant. A laboratory experiment demonstrated that bicarbonate-form anion resins are preferable to hydroxyl-form resins, as long as standards are made from solutions extracted by resins to account for variable ion recovery efficiencies.
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  • 100
    ISSN: 1573-5036
    Keywords: extractable carbon ; fulvic acids ; humic acids ; humification ; mineralization ; nitrogen ; oxidizable carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A calcareous soil was treated with an organic fertilizer mixture of grape debris and peat, or with pig manure, chicken manure, city refuse or with aerobic or anaerobic sewage sludges. Changes in different fractions of carbon and nitrogen were followed by analysis of the soil, immediately after these additions, after they had decomposed for six months in the soil, after a maize harvest, and after a subsequent barley harvest. The various forms of carbon had decreased after six months. The rate of decrease varied with the nature of the organic materials. In all samples, the fulvic acids fraction decreased most. The main transformations happened during the first six months whether there was a crop growing or not, but the crops had no influence on the breakdown of the organic materials. The ratio of humic acids/fulvic acids had increased after six months of humification and, in general terms, the final values of the ratio oxidizable carbon/extractable carbon were lower than the initial ones, indicating a higher degree of humification in the organic matter by the end of the experiment. The total nitrogen level remained practically constant after the first six months of humification even after the second crop. Part of the organic nitrogen of the soil samples amended with chicken manure, city refuse or the two sludges was transformed into mineral nitrogen during the humification process. The extractable nitrogen values increased because of the fertilizer applied during the pot trials.
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