bluuebunny/crossref_metadata_2025 huggingface dataset:
THE P32 INJECTION METHOD FOR STUDYING THE ROOT SYSTEM OF WHEAT
Authors: Racz G. J. , Rennie D. A. , Hutcheon W. L.
Published: March 2010

A new technique involving the use of P32 for the study of plant root development is described. Carrier-free P32 was injected into the stem of wheat plants using a microliter syringe. After allowing 5 days for the P32 to distribute throughout the total plant system, soil–root cores were taken, ashed at 500 °C, and the activity of a pressed soil briquet was determined.The amount of roots measured by the injection method was compared to the more laborious root-washing procedure. Very close agreement between the two methods was realized when the activity of the soil–root cores was recalculated to measure the per cent distribution of the roots within a particular core as compared to the total depth sampled. Preliminary data are reported on experiments designed to estimate the influence of various factors such as phosphate fertilization, soil types, and moisture stress on root development.
EFFECTS OF VARIOUS QUANTITIES OF STRAW MULCH ON THE GROWTH AND YIELD OF SPRING AND WINTER WHEAT
Authors: Anderson D. T. , Russell G. C.
Published: March 2010

The effects of applying a wheat straw mulch at various rates to a trash-free summerfallow field immediately after seeding spring and winter wheat were studied for 9 years. Rates of 4000 and 5000 lb or more per acre significantly depressed mean yields of spring and winter wheat, respectively. Straw at rates of 4000 to 5000 lb completely shaded the soil surface when spread uniformly. Higher rates delayed maturity up to 4 to 6 days, shortened height of plants, occasionally lowered nitrate production, and had a negligible effect on plant population and percentage protein of the grain. Each 1000-lb increment of bright straw depressed the late-morning temperature in the 4- to 8-in. depth of soil by an average value of 0.51° F during the early growth period. The depression increased with the season to a value of 0.65° F by mid-June and then decreased to a value of 0.25° F by mid-July, when the crop, in the headed-out stage, almost completely shaded the soil surface.A quantity of mulch up to 4000 lb per acre can be used without deleterious effects on the crop. Quantities of 4000 lb or more should be managed so that the soil temperature depression associated with complete shading of the soil is avoided.
COMPORTEMENT DIFFERENTIEL DE LA LUZERNE EN REGARD DU CHAULAGE SUR CINQ TYPES DE SOLS DE QUEBEC
Authors: Dionne J. L. , Rola-Pleszczynski S. A.
Published: March 2010

not available
MINERALIZATION OF UREA–FORMALDEHYDE COMPOUNDS AT DIFFERENT pH LEVELS AND TEMPERATURES
Authors: Basaraba J.
Published: March 2010

Mineralization of urea-form fertilizer materials was studied in soils at two different pH levels and five different temperatures. Results show that the nitrogenous materials decomposed very slowly but progressively throughout the incubation period of 14 weeks, and that nitrate was the main product formed. The rates of nitrate production from the urea-form compounds were, in general, from 2 to 5% higher in soil with an initial pH 5.7 than in soil having an initial pH 7.0. At the end of the incubation period, the quantities of nitrate formed from the two urea-form compounds were about equal, amounting to 20, 28, 40, 50, and 58% of the total nitrogen added at 10, 15, 20, 25, and 30 °C respectively. The laboratory results suggested that the urea-form materials studied here could be of only limited value to plants if applied to soils with temperatures below 15 °C during the growing season.
A SWITCHING SYSTEM FOR SOIL MOISTURE–TEMPERATURE PROBES
Authors: Voisey Peter W. , Kloek Martin
Published: March 2010

not available
EFFECT OF RAINFALL ON PLANT RESPONSE TO PHOSPHORUS
Authors: Ferguson W. S.
Published: March 2010

Measurements of the phosphorus content of wheat at intervals during the growing season (1958–1962) indicated that percentage phosphorus in the growing plant was closely related to the amount of rainfall and to frequency of irrigation. The percentage phosphorus decreased during dry years or when irrigation was applied infrequently. This was attributed to the vertical stratification of available phosphorus in the soil since moisture use data indicated that a larger proportion of the active roots zone of the crop was in the phosphorus-deficient subsoil during dry periods. This relationship between percentage plant phosphorus and moisture supply was found with fertilized and unfertilized crops alike. However, frequent watering prior to the 5-leaf stage increased the difference in percentage plant phosphorus between fertilized and unfertilized wheat.Yearly variation (1936–1952) in the degree of plant response to phosphorus on a chernozemic soil was high. The degree of plant response was positively correlated with May rainfall and negatively correlated with June rainfall. It is proposed that this relationship existed because during years of above-normal May rainfall, phosphorus fertilizer was more efficiently utilized and with below-normal June rainfall a higher proportion of root development occurred in the phosphorus-deficient subsoil which increased phosphorus stress in the crop.
SUMMERFALLOW WHEAT PROTEIN VARIATIONS IN SASKATCHEWAN
Authors: McKercher R. B.
Published: March 2010

Field studies were conducted during the years 1957 to 1962 inclusive to measure and delineate factors which cause the protein variations encountered in summerfallow wheat crops in Saskatchewan. Differences in protein content of wheat of over 7% were found between different sampling topographical positions within any one field. Fertilization with nitrogen and phosphate at recommended field rates did not alter the protein content of the grain even though increases in yield of up to 100% were measured. Data are presented which indicate that much of the variation in protein values of wheat within fields can be attributed to changes in the type of soil profile and the associated microclimate.
THE EFFECT OF CULTURAL AND FERTILIZER TREATMENTS ON YIELDS OF WHEAT ON SECOND CROP LAND
Authors: Dawley W. K. , Dryden R. D. , McCurdy E. V. , Molberg E. S. , Bowren K. E. , Dew D. A.
Published: March 2010

Experiments with various cultural and fertilizer treatments on stubble land were conducted at five locations on the prairies from 1955 to 1961 to determine their effect on yields of wheat.Significant yield differences between treatments ranged from 4 to 8 bu of wheat per acre at all stations. At Lacombe, Alta., Melfort and Regina, Sask., the highest average yields were obtained from fall or spring burning of the crop residue followed by normal spring operations. At Lacombe and Melfort, alternative methods gave results which were not significantly different from the burn treatments. These included fall plowing or disking at Lacombe and fall cultivating at Melfort. At Indian Head, Sask., plots which were not tilled in the fall but disked the following spring yielded 5 bu per acre more than those that were fall plowed and 2 bu per acre more than those where burning and tillage was employed. The yields from plots at Melita, Man., which were plowed or one-way disked in the fall produced 7 bu per acre more than those which were not fall tilled and only disked prior to seeding.Fertilizer increased yields of wheat significantly at all stations. Nitrogen at 50 lb with phosphate at 20 lb per acre produced the greatest 5-year average yield at Lacombe and Indian Head. At Melfort, Regina, and Melita, similar returns were obtained with applications of 16 to 50 lb of nitrogen plus 20 lb of phosphate per acre.
THE EVALUATION OF THE RESIDUAL EFFECT OF FERTILIZER IN LONG-TERM FERTILITY PLOTS: II. PHOSPHORUS
Authors: MacLean A. A.
Published: March 2010

Long-term annual applications of fertilizer phosphorus to an acid sandy loam podzol resulted in marked increases in total phosphorus content of the surface soil. However, downward movement was limited as no increase occurred below 9 in. The relationship between total phosphorus content of the profile and sodium bicarbonate-soluble phosphorus (r = 0.93) was significant at the 1% level. Phosphate retention capacity of the surface soil was not influenced by fertilizer or manurial treatment and increases in percentage phosphorus saturation were relatively small.Under conditions of intensive cropping in the greenhouse (12 crops), residual phosphorus was highly effective in supplying crop requirements. However, the results suggest that fertilizer phosphorus may be beneficial during the establishment period. The relationship between phosphorus uptake on the no P series in the greenhouse and levels of sodium bicarbonate-soluble phosphorus (r = 0.88) is further evidence of the value of this method in estimating phosphorus availability in soils.
DETERMINATION OF SUBSIDENCE OF AN ORGANIC SOIL IN SOUTHERN ONTARIO
Authors: Mirza C. , Irwin R. W.
Published: March 2010

The rate of subsidence of the organic soil at the Ontario Agricultural College Muck Experimental Station on the Holland Marsh was measured. Instrumentation was provided to study the effects of secondary influences such as frost action and variations of the water table on the vertical movement of the soil.A linear multiple regression equation was calculated for the average surface elevation of the soil, with time and elevation of the water table as variables.The equation was[Formula: see text]where E was the estimated average surface elevation of the soil in feet, T the time from August 20, 1959, in months, and W the height of the water table from a base elevation of 710.00 feet. The equation was tested by substituting values of average surface elevations determined in 1945 and 1963 and was found to be satisfactory. The rate of subsidence is 1.3 in. per year for the study site on the Holland Marsh.
EFFECT OF MIXING VARYING QUANTITIES OF DICYANDIAMIDE WITH AMMONIUM FERTILIZERS ON NITRIFICATION OF AMMONIA IN SOILS
Authors: Reddy G. R.
Published: March 2010

A series of laboratory experiments were conducted to evaluate the effect of dicyandiamide on the transformation of fertilizer nitrogen in Georgia soils. These studies indicated that dicyandiamide inhibited nitrification of ammonium sulphate at all rates utilized. The inhibitory action of dicyandiamide was attributed to its toxic effect on the nitrifying organisms which failed to function in the presence of dicyandiamide. Complete nitrification eventually occurred but only after a long period.Decomposition of dicyandiamide was more rapid in fine-textured Cecil sandy loam containing relatively more organic matter than on the coarse-textured and low organic matter Lakeland sandy soil. Soil texture and organic matter content are two factors that must be considered in evaluating the length of time that dicyandiamide will inhibit nitrification in any given soil.Sucrose apparently provided a quickly available source of energy for soil microorganisms that utilized the dicyandiamide as a source of nitrogen and preventing its inhibiting effect on nitrification. The nitrogen from the dicyandiamide was eventually mineralized as indicated by the higher total ammonium and nitrate nitrogen found at the end of incubation period.
THE UPTAKE OF S35 BY CROPS FROM VARIABLE DEPTHS IN THE SOILS
Authors: Pawluk S. , Bentley C. F.
Published: March 2010

not available
EVALUATION OF METHODS FOR DETERMINATION OF TOTAL ORGANIC PHOSPHORUS IN CHERNOZEMIC SOILS OF SOUTHERN ALBERTA
Authors: Dormaar J. F.
Published: March 2010

Two Orthic Chernozemic profiles of each of four parent materials were selected at undisturbed sites within the Brown, Dark Brown, and Thin Black soil zones of southern Alberta. This constituted 24 profiles representing 12 Chernozemic soil series. Material from the Ah and Bm horizons was subjected to nine procedures for estimating total organic phosphorus.The data of this study generally substantiated the usefulness of a modified Kaila–Virtanen method for these soils. With some soils, such as those from the Brown soil zone and those developed from aeolian parent material, other methods gave similar results. Reproducible results were obtained with only four methods.The efficiency of estimation of some of the methods decreased as organic phosphorus content of the soil increased. This, together with several other observations, suggests that the organic phosphorus of soils cannot be measured quantitatively at present. Several of the comparisons between methods, however, will be useful for further qualitative work.
FURTHER INVESTIGATIONS ON THE ALKALINE PERMANGANATE OXIDATION OF ORGANIC MATTER EXTRACTED FROM A PODZOL Bh HORIZON
Authors: Schnitzer M. , Desjardins J. G.
Published: March 2010

Organic matter extracted from a Podzol Bh horizon was oxidized with alkaline permanganate. The oxidation product was extracted with organic solvents. The material soluble in the organic solvents was methylated and then distilled under vacuum. By means of gas chromatography the methyl esters of the following benzene carboxylic acids were identified in the distillate and estimated quantitatively: 0.03% o-phthalic acid, 0.05% trimellitic acid, 0.05% pyromellitic acid, 0.05% prehnitic acid, 0.06% mellophanic acid, 0.08% benzene pentacarboxylic acid, and 0.06% mellitic acid. These yields are expressed on the basis of the original dry ash-free organic matter.The compounds identified are discussed in relation to the probable chemical structure of the organic matter and to previous investigations on the same organic matter.
POTASSIUM AND PHOSPHORUS ACCUMULATION IN ORGANIC SOIL AND THEIR INFLUENCE ON POTATO CROPS
Authors: Jasmin J. J. , Tourchot R. , Heeney H. B.
Published: March 2010

Repeated application of fertilizer over a 5-year period (1957–61) on organic soil producing potatoes resulted in large increases in exchangeable potassium and in moderate increases in acid-soluble plus absorbed phosphorus. Where potatoes were grown without application of fertilizer the exchangeable potassium decreased rapidly but the available phosphorus remained at a constant level.Fertilizer treatments influenced yields only in 1961, and per cent total N and P in leaf tissue only in 1961 and 1958 respectively. However, in all years the per cent total potassium in leaf tissue was in direct relation to rate of fertilizer applied and the percentage of Ca and Mg generally decreased as per cent potassium increased. The specific gravity and the general boiling quality of the tubers were adversely affected by heavy fertilization, but the chipping quality, the flavor, and the color of the flesh were not affected by soil fertility differences.
THE EFFECT OF SOIL CARBONATE LEVEL ON THE AVAILABILITY OF ADDED AND NATIVE PHOSPHORUS IN SOME CALCAREOUS MANITOBA SOILS
Authors: Soper R. J. , ElBagouri I. H. M.
Published: March 2010

Chemical and biological procedures were used to evaluate the effect of soil carbonate level on the availability of recently added and native soil phosphorus. Oats were grown in a greenhouse in surface soils which ranged in calcium carbonate equivalent from 0.5 to 33.1%.The results indicated that the level of carbonate in the soil per se had no bearing on the availability of native phosphate or on the availability of added phosphate which remained in a relatively available form. Fractionation of the soils before and after cropping according to the Jackson procedure revealed that amounts of either native or added phosphorus in each fraction were not related to the carbonate level.
INFLUENCE DE L'INTOXICATION MANGANIQUE SUR SIX VARIÉTÉS DE POMME DE TERRE
Authors: Ouellette G. J. , Généreux Henri
Published: March 2010

not available
EXTRACTION OF EXCHANGEABLE CATIONS FROM WYOMING BENTONITE SUSPENSIONS
Authors: Clark J. S.
Published: March 2010

Wyoming bentonite suspensions were prepared with a range of per cent Ca saturations and the exchangeable cations were extracted with solutions of NaCl, KCl, NH4Cl, and CaCl2. The per cent base saturation values, (Ca/Ca+Al)) × 100, obtained both by serial extraction with 1 N salt solutions and by a single extraction with 2 N NaCl or KCl agreed closely with the theoretical base saturation values calculated from the corrected lime potential. Somewhat better agreement with the theoretical values was obtained, however, with a single extraction than by serial extraction. The sum of Ca + Al (effective C.E.C.) was less affected by changing extract to clay ratio when a single extraction was employed. For these reasons, it was concluded that a single extraction with 100 ml of 2 N NaCl or KCl for 0.5 to 2.5 meq of exchange sites should be employed for the determination of exchangeable cations in clays and soils.
PROPERTIES AND GENESIS OF THREE MEMBERS OF THE UPLANDS CATENA
Authors: McKeague J. A.
Published: March 2010

Field measurements were recorded of water table, Eh, moisture, and temperature for three members of the Uplands catena throughout 2 years. Samples of the Orthic Podzol (Uplands), Gleyed Orthic Podzol (Rubicon), and Orthic Gleysol (St. Samuel) were analyzed.High Eh values (above 600 mv) and a water table below 4 ft prevailed at the Uplands site. The soil had well-developed Ae and Bfh horizons. High Eh values prevailed at the downslope Rubicon site except for a few weeks each spring when the water table was at the surface. The soil had strongly developed Ae, Bhf, and Bfhg horizons. The water table remained at or near the surface at the depressional St. Samuel site. The Eh values in the upper 2 ft fluctuated appreciably; below this depth, they remained low (0 ± 150 mv). The brownish Bfg horizon was high in free iron oxide but low in organic matter and in free aluminum. Oxidation of ferrous iron from the underlying reduced-zone apparently contributed toward the development of this horizon.Montmorillonite is the dominant phyllosilicate in the Ae horizons and chloritized vermiculite in the B horizons of both Podzols. In St. Samuel, the dominant phyllosilicates are vermiculite in the Aejg horizon, and montmorillonite and mixed-layer material in the Bfg horizon.Morphological, chemical, and mineralogical properties of three members of the Uplands catena are related closely to redox conditions.
MOISTURE TENSION, DIFFUSIVITY, AND CONDUCTIVITY OF A LOAM SOIL DURING WETTING AND DRYING
Authors: Staple W. J.
Published: March 2010

Soil moisture tensions, diffusivities, and conductivities in packed columns of Grenville silt loam during wetting were compared with those during drying. In the moisture range 0.3 to 0.4 cm3/cm3 tensions on wetting were only one third of those on drying. Diffusivities and conductivities on wetting exceeded those on drying in the ratios 5:1 and 10:1 respectively. These data depended on the bulk density and particle size distribution of the soil. The observed wetting to drying ratios of D and K should be representative for fragmented surface soils although lower ratios may occur below plow depth.
AN INEXPENSIVE MATERIAL FOR LINING SOIL TRENCHES
Authors: Clements John R.
Published: March 2010

not available
FIXED AMMONIUM IN SOME ALBERTA SOILS
Authors: Moore A. W.
Published: March 2010

not available
EFFECT OF RATE AND TIME OF NITROGEN AND INTERVAL OF PHOSPHORUS AND POTASSIUM FERTILIZATION ON HERBAGE PRODUCTION ON PERMANENT PASTURE
Authors: MacLeod L. B. , Jackson L. P. , Bishop R. F. , MacEachern C. R.
Published: March 2010

In two 3-year cycles of a field experiment annual N treatments were superimposed on mineral treatments applied annually and triennially to a permanent pasture sward.Applications of P and K were reflected by changes in exchangeable K and acid-soluble plus adsorbed P. There was somewhat greater penetration of K than of P and soil levels of both were generally lowest where rate of N application was highest.Yields varied from year to year but tended to be more uniform with annual than with triennial mineral treatments. In the 6-year period average yields for all 0-, P-, K-, and P–K-treated plots were approximately 1.3, 1.6, 1.5, and 2.0 tons per acre of dry matter. Time of nitrogen application had little influence on total yield but seasonal distribution of herbage was much more uniform with nitrogen applied in summer than in spring. Soil moisture, which was a major factor in the response obtained with nitrogen applied in summer, was limiting during the late summer in two of the three years measured.Percentages of P and K in grass reflected the mineral treatments which had much less influence on botanical composition and species foliage cover than N. This element suppressed legumes, increased grass, and markedly influenced the K level in grass.
A HYDRAULIC INSERTER FOR INSTALLING FIBER-GLASS SOIL MOISTURE UNITS
Authors: Weegar H. H. , Groenewoud H. van
Published: March 2010

not available
EFFECT OF LIMESTONE ON PASTURE SWARD RENOVATION WITH AND WITHOUT CULTIVATION
Authors: Calder F. W. , MacLeod L. B. , Bishop R. F. , MacEachern C. R.
Published: March 2010

Increases in herbage production ranging from approximately 43 to 96% resulted when various rates of limestone, together with fertilizer and a forage seed mixture, were applied to the surface of a sparse sward. When these treatments were applied to the surface of a dense sward increases ranged from approximately 9 to 25%. On both sward types cultivation and incorporation of fertilizer and limestone almost invariably produced yields which were significantly higher than those obtained when the treatments were applied on the surface.
SULPHATE IONS AND CATION EXCHANGE REACTIONS WITH CLAYS
Authors: Singh S. Shah , Turner R. C.
Published: March 2010

The effect of replacing NO3− with SO42− in solution on exchange between Al3+ or Fe3+ and Ca2+ was investigated for aqueous acid clay systems. It was found that if the activities of the cations in solutions were not corrected for soluble cation–SO42− complexes the results with SO42− were definitely different from those with NO3−. When the corrections for complexing were made there was little if any difference between the results with the two anions, as far as exchange reactions and the relation between adjusted lime potential and degree of Ca2+ saturation of clays were concerned. The presence of SO42−, however, had a marked effect on the ion product (Fe) (OH)3 but not on (Al)(OH)3 in solution.
THE EFFECT OF METHODS USED TO BREAK VIRGIN WOODED SOILS ON THE YIELDS OF WHEAT AND FLAX
Authors: Hennig A. M. F.
Published: March 2010

Yields of wheat and to a lesser extent flax were greater following June breaking of virgin bushland than following September breaking. Shallow moldboard breaking was superior to deep breaking for the production of wheat but deep breaking generally gave the higher yield of flax. Land broken with a moldboard plough produced a higher yield of flax than land broken with a serrated disc plough but moldboard breaking had less advantage for the production of wheat.Yield differences among the breaking methods were sharply reduced in the second cropping year for both wheat and flax, and wheat yield differences disappeared by the fifth crop. Yield differences among the breaking methods were also markedly reduced by summerfallowing before cropping to wheat. Regrowth of native willow (Salix sp.) and poplar (Papulus sp.) were also affected by the breaking methods but a definite relationship between amount of regrowth and crop yields could not be shown.
Sr90 CONCENTRATION IN DEEP- AND SHALLOW-ROOTING SPECIES AS AFFECTED BY PLACEMENT OF Sr90 AND FERTILIZER TN THE SOIL
Authors: Evans E. J. , Dekker A. J.
Published: March 2010

In greenhouse experiments involving the placement of Sr90 and fertilizer in the soil, marked reductions in Sr90 concentration were found for timothy and wheat when the Sr90 was placed deep in the soil compared with the results found for shallow placement. Fertilization of the soil above the zone of Sr90 contamination led to further decreases in Sr90 concentration in timothy and wheat.Results for alfalfa differed from the results for timothy and wheat. A combination of shallow fertilization and shallow placement of Sr90 caused the highest concentration of Sr90 in plants. Deep placement of Sr90 did not reduce the Sr90 concentration in the first cutting of alfalfa, but as the plant matured, there was a reduction caused by deep placement of Sr90. Deep placement of Sr90 combined with deep placement of fertilizer caused an increase in the Sr90 concentrations in alfalfa compared with deep placement of Sr90 alone. The greatest reductions in Sr90 in the plants were found where the deep placement of Sr90 was combined with shallow placement of the fertilizer. Surface or subsurface watering of the crop did not affect the main conclusions with regard to placement of Sr90 and fertilizer.
DISTRIBUTION OF ORGANIC MATTER AND PHOSPHORUS FRACTIONS IN A TOPOGRAPHIC SEQUENCE OF SOILS IN SOUTHERN BRITISH COLUMBIA
Authors: Floate M. J. S.
Published: March 2010

In sequences of grassland soils on south-facing slopes and forested soils on north-facing slopes in southern British Columbia, pH decreased but C, N, and organic phosphorus (Po) increased with increase in elevation from 1800 to 7400 ft. At the highest elevations grassland and forested soils contained similar amounts of C, N, and Po. The surface horizons of grassland soils at the lowest elevations contained C and N in similar amount to forested soils between 4000 and 5000 ft. C, N, and Po decreased with depth in all profiles but the amount of H2SO4-soluble inorganic P (Pa) increased to its highest percentage of the total, up to 98%, in the parent materials. Although both C/N and C/Po ratios decreased with depth, the values for C/Po were not high and indicated that inorganic phosphorus supply is not limiting the accumulation of P in the soil organic matter. These properties were interpreted as the effects of climate, modified by elevation, aspect, and vegetation, on weakly weathered parent materials.
Espasticidade
Authors: Chinelato Júlio César de Andrade , Perpétuo Adriane Mazola de Araújo , Beck Eddy Krueger
Published: March 2010

O distúrbio de maior frequencia das desordens do neurônio motor superior é a espasticidade, caracterizada por uma hiperexcitabilidade dos reflexos miotáticos e cutâneos que fomentam o tônus muscular (hipertonia espástica). O propósito deste estudo foi fazer um levantamento literário analisando os aspectos neurofisiológicos e musculares possivelmente envolvidos na espasticidade e como a Toxina Botulínica do tipo A (TBA) age no controle e redução da espasticidade. Os resultados encontrados na literatura demonstram claramente melhora no tônus muscular de pacientes submetidos ao uso da TBA. Os testes que combinam a TBA e Fisioterapia, prevaleceram aos grupos de controle que foram somente submetidos à Fisioterapia ou a aplicação de TBA isolados. Ademais, estudos recentes sugerem a presença da TBA em circuitos do sistema nervoso central, provavelmente conduzida via fluxo axoplasmático retrogrado e transcitose. Os mecanismos envolvidos na espasticidade são ainda pouco compreendidos e os efeitos da TBA a longo prazo em humanos ainda não são bem conhecidos. Por este motivo, novas pesquisas deverão ser realizadas a fim de verificar a viabilidade e segurança de tratamentos empregando esta substância de efeito letal em seres humanos.
Environmental Hazard Assessment of Bioinsecticides as a New Perspective for Ecotoxicology in Brazil
Authors: Oliveira-Filho Eduardo Cyrino
Published: March 2010

Biological products or biopesticides have been presented as an interesting alternative to the traditional chemical products used to control pests in livestock, agriculture and public health. Due to its insecticide action, independent of their origin, these products are regulated by the federal legislation of pesticides. The main concerns are related to the potential impacts on the environment and on the health of the exposed population. Recently, with the publication of the Normative Instruction no 3, in March 10 of 2006, regulatory agencies have defined specific requirements for biopesticides registration in Brazil, and among these requirements are several ecotoxicity assays. In this way, this review inform what are the microorganisms with registration for use in Brazil, describes the assays requested for registration and comments available results in literature about the ecotoxicity of these agents. The studies presented showed different situations where many times the agent’s specificity is not so significant and in some cases non-target species can be affected. Besides, the acquisition of these data could orientate the researches with microorganisms predicting the environmental feasibility of its releases in field experiments. All these information emphasize the importance of ecotoxicology in the environmental hazard assessment of bioinsecticides and configure this field of action as more one for this science in Brazil.
Selectivity of the Insecticide Metamidophos on Eight Not-target Terrestial Organisms
Authors: Iannacone José , Alvariño Lorena , Murrugarra Y. , Arrascue Anita , Alayo Marianela , Salazar Neil
Published: March 2010

The organophosphorus methamidophos is one of the most employed pesticides in Peruvian agriculture. This research aimed to evaluate the ecotoxicological effect of two formulations of methamidophos belonging to different toxicological classes [Monofos®, class Ia (extremely dangerous), and Tamaron®, class Ib (highly dangerous)] on eight non-target terrestial organisms: Eisenia foetida (Savigny, 1826) (Oligochaeta: Lumbricidae), Porcellio laevis (Latreille, 1804) (Isopoda: Porcellionidae), Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae), Orius insidiosus (Say, 1832) (Hemiptera: Anthocoridae), Podisus nigrispinus (Dallas, 1851) (Heteroptera: Pentatomidae), Cryptolaemus montrouzieri (Mulzant, 1853) (Coleoptera: Coccinellidae), Copidosoma koehleri (Blanchard, 1940) (Hymenoptera: Encyrtidae) and Leptomastidea abnormis (Girault, 1915) (Hymenoptera: Encyrtidae). The sequence of higher to low risk quotients (RQ) to methamidophos Ia was: L. abnormis > C. koehleri > O. insidiosus > P. laevis > C. externa > C. montrouzieri. However, to methamidophos Ib was: L. abnormis > E. foetida > O. insidiosus > C. koehleri > P. laevis > C. externa > P. nigrispinus. Both formulations of methamidophos produced high risk of effect to L. abnormis and low risk to C. externa, C. montrouzieri and P. nigrispinus at doses recommended for pest control. RQ indicated that use of methamidophos is highly risky to terrestial environment.
Effects of Surfactants DSS and LAS-C12 on Pink Shrimp (Farfantepenaeus paulenssi, Pérez-Farfante, 1967)
Authors: Barbieri Edison
Published: March 2010

An evaluation was done of acute toxicity of the SDS (Sodium Dodecil Sulfonate) and LAS-C12 (Linear Alkylbenzene Sulfonate) using red shrimp (Farfantepenaeus paulensis) exposed to different concentration, for periods of up to 96 hours. The acute toxicity of SDS in larvae of the pink shrimp exposed to different concentrations of this substance were: 13,66 mg L–1 for 24 h of exposure; 11.89 mg L–1 for 48 h; 9.98 mg L–1 for 72 h, and 8.66 mg L–1 for 96 h. For LAS-C12 the acute toxicity in larvae of the pink shrimp exposed to different concentrations of this substance, for period of up to 96 h were 6.37 mg L–1 for 24 h of exposure; 5.32 mg L–1 for 48 h; 4.61 mg L–1 for 72 h; and 4.25 mg L–1 for 96 h.
Sensitivity of the Sea Urchin Arbacia lixula (Echinodermata: Echinoidea) in Toxicity Tests
Authors: Máximo Marcus Vinicius , Mottola L. S. M. , Resgalla Jr. Charrid
Published: March 2010

This study investigates the sea urchin Arbacia lixula in terms of embryonic and larval development time, development tolerance in different salinities and maintenance water temperatures, its repeatability in the presence of reference toxicants used in toxicity tests, and its sensitivity in comparison with other species of sea urchin normally used in Brazil. The embryonic development of A. lixula at 25°C rapidly reached the larval stage pluteus in less than 24 hours, therefore it was not necessary to extend the period of the experiments. However, it presents some disadvantages such as a fertilization membrane that is not very clear, and often with a fertilization rate from 70 to 80%. The experiments to determine the viability of the embryos in different salinities and temperatures demonstrated a wide tolerance, with a normal development of 24 h between the  salinities of 29 and 39 and 20 h for 30ºC of temperature. The toxicity tests carried out with the reference toxicant resulted in values for variation coefficients lower than 30% for chromium and zinc, demonstrating that the tests are repeateable. When compared with other sea-urchin species (Lytechinus variegatus and Echinometra lucunter), A. lixula presented sensitivity of the same order and scale, and similar results were obtained for the environmental samples (sediment elutriate).
Natural Products
Authors: Spainhour Charles B.
Published: March 2010

The use of natural products for therapy has evolved from being therapeutic agents to serving as a platform for drug discovery and development. According to World Health Organization, natural products are the direct or indirect source of majority of the current medicines. This article focuses on discovery and development of modern drugs from natural products.
Systems Biology: Applications in Drug Discovery
Authors: Ekins Sean , Bugrim Andrej , Nikolsky Yuri , Nikolskaya Tatiana
Published: March 2010

System biology is the analysis of complex genes and proteins in an organism by integrating proteomic, genetic, metabonomic, and transcriptomic data through computational methods. It is rapidly becoming a leading approach to the integration and mining of data in human biology. This article discusses various utility, applications, and limitations of the tools and databases for such analysis.
Using Microsoft Excel® as a Laboratory Data Management Tool
Authors: Rubin A. Erik , Russo Mark F. , Neil William
Published: March 2010

Excel can be used by scientists for managing data management troubles ranging from simple tasks such as devising a system to store printouts of high‐performance liquid chromatography (HPLC) chromatograms and link them to entries in one's notebook to complicated scenarios such as creating a data storage and visualization application for a high‐throughput workflow that operates 24 h a day. There is an underappreciation for the wide diversity of data management tasks that can be handled by Excel and VBA. This article describes Excel's utility as a laboratory data management tool.
Design and Pharmaceutical Applications of Prodrugs
Authors: Järvinen Tomi , Rautio Jarkko , Masson Mar , Loftsson Thorsteinn
Published: March 2010

Prodrugs are pharmacologically inactive derivatives of drug molecules that require a chemical or enzymatic transformation in order to release the active parent drug in vivo, prior to exerting a pharmacological effect. Prodrug design aims to overcome limitations of a parent drug that would otherwise hinder its clinical use. Prodrug design and research should be more involved in the lead optimization step during the drug discovery process. This article focuses on the design and pharmaceutical applications of prodrugs.
Factors Influencing the Efficacy of Mediator‐Specific Anti‐Inflammatory, Glucocorticoid, and Anticoagulant Therapies for Sepsis
Authors: Minneci Peter C. , Deans Katherine J. , Haley Michael , Cui Xizhong , Natanson Charles , Eichacker Peter Q.
Published: March 2010

Sepsis is a major cause of mortality for hospitalized patients worldwide with a mortality rate estimated to be between 30 and 60 percent. It is observed that during sepsis, cardiovascular dysfunction is produced by bacterial infection with the release of bacterial toxins and the production of harmful host mediators. This article focuses on the rationale for targeting inflammatory and coagulant pathways during sepsis, reviews the clinical experience with mediator‐specific anti‐inflammatory agents, steroids, and anticoagulants, and highlights factors that growing evidence suggests may influence their efficacy.
Combinatorial Chemistry in the Drug Discovery Process
Authors: Ross Nathan T. , McNaughton Brian R. , Miller Benjamin L.
Published: March 2010

In recent years, combinatorial chemistry has evolved as an attempt to significantly shorten the lead identification and lead optimization portions of drug development. Combinatorial chemistry has become a widely used tool for synthetic chemists looking to streamline lead identification and for those needing novel structures to drive a plethora of studies in chemistry, biology, materials science, and beyond. This article describes the characteristics and applications of combinatorial chemistry in the drug discovery process.
Respiratory Viruses
Authors: Olivo Paul D.
Published: March 2010

Viruses cause cell death, organ malfunction, or elicit an inflammatory reaction that can account for many of the symptoms and pathology of infection. Respiratory viral infections have a major impact on health and cause an immense amount of human morbidity and mortality. This article focuses on the impact of respiratory viruses on health and therapeutic potential of antiviral therapy to control these agents.
Targets and Approaches for Cancer Drug Discovery
Authors: Mooberry Susan L.
Published: March 2010

Although significant advances in early diagnosis and treatment of cancer have been made in the past decade, there remains a compelling need for more effective therapies for the treatment of many different types of cancer. Accurate predictive diagnostic tools are necessary to identify the molecular defects of tumors to allow for individualized targeted therapy. This chapter provides an introduction to the field of cancer drug discovery, focusing on a subset of current targets and giving a brief overview of approaches for identification of leads and sources of materials for drug discovery efforts.
Method Development for Preclinical Bioanalytical Support
Authors: Khan Masood , Weng Naidong
Published: March 2010

Preclinical development represents a critical stage in the progression from discovery to marketed pharmaceutical drug candidates that have passed initial discovery screening and are identified to possess some drug‐like properties. Bioanalytical support at the preclinical development phase presents some unique challenges such as Good Laboratory Practice (GLP) and good metabolic selectivity coverage requirements. This article focuses on general bioanalytical method development, validation, sample analysis and practical experience on preclinical bioanalytical support.
Absorption of Drugs after Oral Administration
Authors: Granero Luis , Polache Ana
Published: March 2010

After oral administration, drugs must be absorbed through the gastrointestinal tract to achieve the systemic circulation and exert their pharmacological effects. The successful formulation of an optimized oral drug delivery system requires a detailed consideration and a good understanding of the intestinal absorption process, its possibilities and limitations. This article gives an overview and update on the concepts, possibilities, and limitations of drug absorption after oral administration.
Distribution: Movement of Drugs through the Body
Authors: Panyam Jayanth , Patil Yogesh
Published: March 2010

Drug distribution refers to the reversible movement of drug from blood to various tissues of the body. Following entry into the systemic circulation, a drug distributes into different tissues, the rate and extent of which is dependent on the drug's physicochemical properties and the blood flow to the tissues. This article focuses on the various factors affecting drug distribution and the different approaches available to modify drug distribution.
The Blood – Brain Barrier and its Effect on Absorption and Distribution
Authors: de Boer A. G. , Gaillard P. J.
Published: March 2010

Potential drugs for the treatment of most brain diseases are often not able to cross barriers protecting the central nervous system (CNS). As a result, various drug delivery and targeting strategies are currently being developed to enhance the absorption and distribution of drugs into the brain. This article discusses the biology and physiology of the blood–brain barrier (BBB) and the blood–cerebrospinal fluid barrier with respect to drug transport (absorption, distribution), the in vitro and in vivo methods to measure BBB transport, and the possibilities to deliver large molecular drugs, by viral and receptor‐mediated nonviral drug delivery, to the (human) brain.
Transporter Interactions in the ADME Pathway of Drugs
Authors: Zhang Yan , Miller Donald W.
Published: March 2010

Interactions of therapeutic agents with endogenous transporter systems have a major impact on the absorption, distribution, metabolism, and excretion (ADME) properties of drugs. Pharmaceutical scientist has a variety of tools to probe transporter interactions of compounds. This article focuses on some of the important transporters that can influence the ADME properties of drugs and a strategy for evaluating compounds for transporter interactions.
Accumulation of Drugs in Tissues
Authors: Venkatesan Krishnamurthy , Bisht Deepa , Owais Mohammad
Published: March 2010

Drugs need to achieve an adequate concentration in their target tissues in order to exert pharmacological action. The concentration of a drug at any moment and in any region of the body depends on translocation of the drug molecules and the chemical transformations they undergo due to metabolic action. This article focuses on movement of drug molecules across cell barriers, absorption, distribution, and various approaches for drug delivery.
Dissolution
Authors: Tiwary A.K. , Sapra Bharti , Jain Subheet
Published: March 2010

Dissolution of the active ingredients is of paramount importance for the successful performance of a dosage form. Dissolution testing is a convenient tool for ensuring intra‐ and interbatch performance compliance of dosage forms. This article focuses on factors influencing drug dissolution from dosage forms, dissolution test designing, and analysis of dissolution data
In VivoMetabolism in Preclinical Drug Development
Authors: Rollas Sevim
Published: March 2010

In preclinical drug discovery, investigation of the in vitro, in vivo metabolism and toxicity screening of a drug candidate together play a very important role in the drug's success before entering into clinical use. Several in vitro models, such as isolated perfused livers, liver tissue slices, freshly isolated hepatocytes in suspension, primary hepatocyte cultures, cell lines, microsomes, mitochondria, and expression systems have been developed to profile human metabolism. This article focuses on the preclinical in vivo metabolism of drug candidates and prodrugs.
Mechanisms and Consequences of Drug–Drug Interactions
Authors: Farkas Dora , Shader Richard I. , von Moltke Lisa L. , Greenblatt David J.
Published: March 2010

Understanding the mechanisms and consequences of drug–drug interactions is essential for the development of new pharmaceuticals and for the design of multidrug regimens. Drug interactions occur when one drug changes the pharmacokinetic and/or the pharmacodynamic actions of another drug. This article focuses on the common mechanisms of drug–drug interactions and pharmacokinetic principles of drug interactions, including different experimental systems and modeling tools used to investigate possible drug interactions.
Species Comparison of Metabolism in Microsomes and Hepatocytes
Authors: Krebsfaenger Niels
Published: March 2010

Species differences in metabolism may have significant impact on pharmacokinetics and toxicity of drugs. Therefore detailed knowledge of comparative metabolism across species is key for species selection in preclinical safety testing and interpretation of any animal data in respect to relevance for humans. This article focuses onin vitrospecies comparisons, which support a preliminary species selection for preclinical safety testing and interpretation of animal data.
Linkage Between Toxicology of Drugs and Metabolism
Authors: Zhang Ruiwen , Rayburn Elizabeth R.
Published: March 2010

Although our ability to identify candidate lead compounds with high potency and specificity has largely been improved, many candidate therapeutic agents are prevented from reaching the market due to inappropriate pharmacokinetic/ADME properties and drug‐induced toxicity. As a consequence, over the past decades, ADME and toxicity (ADMET) screening studies have been incorporated earlier into the drug discovery phase for removal of poorly behaved drugs in the discovery and early development phases. This article focuses on fundamental ADMET concepts, key tools, reagents, and experimental approaches for predicting human pharmacokinetics and assessing “drug‐like” molecules, with an emphasis on the link between toxicology and metabolism.
Experimental Design Considerations in Pharmacokinetic Studies
Authors: Hope William W. , Petraitis Vidmantas , Walsh Thomas J.
Published: March 2010

Pharmacokinetic studies are conducted in experimental contexts to define pharmacokinetic relationships for new drugs that may be beneficial for patients and to enable the understanding the concentration‐effect relationships. For both these purposes, an accurate description of pharmacokinetics is vital, which can be achieved by appropriate experimental design. This article describes some of the issues in the design of experimental models, which enable pharmacokinetic relationships to be established.
Pharmacodynamics
Authors: Shin Beom Soo , Shah Dhaval , Balthasar Joseph P.
Published: March 2010

Pharmacodynamics refers to the study of relationships between drug concentrations and pharmacological effects. The mathematical description of these relationships, through the use of appropriate pharmacodynamic models, facilitates the characterization and comparison of candidate drugs, facilitates the rational selection of appropriate dosing regimens, and assists in the investigation and identification of the mechanisms associated with drug action. This article provides an overview and a catalog of mathematical models that may be employed to characterize drug pharmacodynamics.
Regulatory Requirements forINDs/FIH(First in Human) Studies
Authors: Gad Shayne Cox
Published: March 2010

The safety of pharmaceutical agents, medical devices, and food additives is the toxicology issue of the most concern to the public. Chapter 1, Title 21 of theCode of Federal Regulations(21 CFR) govern the testing, manufacture, and sale of pharmaceutical agents in the U.S. This article examines the regulations that establish how the safety of human pharmaceutical products is evaluated and established in the United States and the other major international markets prior to initial trials in human beings.
Use of Project Teams in Preclinical Development
Authors: Keefe Dorothy M. K. , Bowen Joanne M. , Gibson Rachel J.
Published: March 2010

Preclinical development of a drug is that part of drug development that occurs before the drug enters human trials. The process includesin vitroandin vivostudies of efficacy, safety, pharmacokinetics, and pharmacodynamics, in order to produce pharmaceutical grade materials. This article highlights the role and use of project teams in preclinical development.
Repeat Dose Toxicity Studies
Authors: Gad Shayne Cox
Published: March 2010

Repeat dose toxicity studies are those studies whereby animals have a therapeutic agent administered to them on a regular and repeated basis by one or more routes. Repeat dose study is a broad exploration of the cumulative biological effects of the administered agent over a range of doses. This article focuses on various objectives for repeat dose studies, the regulatory requirements governing them, and the key factors in their design and conduct.
Safety Assessment Studies: Immunotoxicity
Authors: Descotes Jacques
Published: March 2010

The clinical shift from immunology to toxicology resulted in the introduction of toxicological concepts in immunotoxicity evaluation. Current procedures for assessing the immunotoxicological safety of medicinal products have some shortcomings. Nonclinical immunotoxicity evaluation is currently limited to unintended immunosuppression. This article discusses various safety factors related to immunotoxicity, including preclinical assessment of immunosuppression and models of IgE mediated hypersensitivity reactions.