bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intracellular Ca2+ concentration and H2O2 production in mouse peritoneal macrophages are stimulated by platelet activating factor
Authors: Sasaki Masayuki , Maeyama Kazutaka , Watanabe Takehiko 
Published: February 2007

AbstractThe intracellular calcium concentration ([Ca2+]i) in mouse peritoneal macrophages cultured on a coverglass was measured in the superfusion system using fura‐2 as a fluorescent calcium probe and platelet activating factor (PAF) as a stimulant. In the presence of extracellular Ca2+, 10−7M PAF sharply increased [Ca2+]i from a basal level of 90 nM to 340 nM. Thereafter, the [Ca2+]i level gradually decreased in two phases, in an initial rapid phase and a subsequent slow phase of decrease. The calcium response was dependent on the PAF concentration. In the absence of extracellular Ca2+, a single sharp peak was observed, suggesting two different modes of Ca2+ movement, one from intracellular stores and the other from the extracellular medium. A simple, sensitive fluorometric assay system was developed for measuring H2O2 in the superfusate of macrophages after stimulation by use of immobilized peroxidase and 3‐(p‐hydroxyphenyl)propionic acid as a fluorogenic substrate. With this system, as little as 2 pmol of H2O2 could be measured. PAF (1 μM) increased H2O2 production in peritoneal macrophages in the presence of extracellular Ca2+, but H2O2 production was not observed in the absence of extracellular Ca2+.
Platelet‐activating factor stimulates receptor‐mediated fromation of reactive oxygen intermediates in human monocytes
Authors: Pustynnikov M. G. , Porodenko N. V. , Makarova O. V. , Kozyukov A. V. , Moskaleva E. Yu. , Sokolovsky A. A. , Severin E. S. 
Published: February 2007

AbstractStimulation of production of reactive oxygen intermediates (ROI) was examined in human peripheral blood monocytes by luminol‐dependent chemiluminescence. The dose‐response cureve characterizing the dependence of ROI production on the concentration of platelet‐activating factor (PAF) showed that stimulation occurred within a concentration range of 2×10−9M to 5×10−6M. Transformation of the dose‐response curve to an Eadie‐Hofstee plot indicated that the process is characterized by two Km values. The Km value corresponding to the high‐affinity branch of the curve is 1.3±0.14 nM. In the same cells, the dissociation constant for the [3H]PAF/receptor complex was determined. The Kd value was 0.8±0.1 nM, which agreed quite well with the high‐affinity Km value obtained in the Eadie‐Hofstee plot. The data indicate that stimulation of ROI generation is mediated through PAF binding at specific receptor sites at nanomolar PAF concentrations. Along with the specific receptor‐mediated ROI generation, a nonspecific effect of PAF at a high concentration was demonstrated.
Role of platelet‐activating factor (PAF) in superoxide production by human polymorphonuclear leukocytes
Authors: Takahashi Shuji , Yoshikawa Toshikazu , Naito Yuji , Tanigawa Toru , Yoshida Norimasa , Kondo Motoharu 
Published: February 2007

AbstractThe effect of platelet‐activating factor (PAF) in superoxide production by human polymorphonuclear leukocytes (PMN) was studied. Cypridina luciferin analog (CLA) dependent chemiluminescence was used to detect superoxide anion radicals. PAF induced superoxide generation in human PMN in a dose‐dependent manner. Preincubation with a small amount of PAF (5 x 10−9 M) enhanced PMN superoxide release induced by various stimuli, such as phorbol myristate acetate (PMA), opsonized zymosan (OZ), calcium ionophore (A23187) andN‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP). The PAF antagonist, CV‐6209, inhibited superoxide production induced by PAF, but not that induced by other stimuli. These findings would indicate that PAF may play an important role at inflammatory reaction sites and that CV‐6209 may inhibit excessive inflammatory reaction.
Platelet activating factor‐induced pulmonary accumulation of111indium‐oxine labelled neutrophils in anesthetized guinea pigs
Authors: Hultkvist‐Bengtsson Ursula , Anderson Gary P. , Kings Madeleine , Morley John 
Published: February 2007

AbstractThe thoracic accumulation of neutrophils labelled with111Indium‐oxine in response to infusion of platelet activating factor (PAF, 18 ng/kg/min × 5 min, i.v.) was studied using an automated isotope monitoring system (AIMSplus) in anesthetized guinea‐pigs. Loss of cell associated radioactivityin vitro was less than 1% over 4 hr. Labelled neutrophils maintained their functional capacity (oxidative response to the cell stimulants N‐formyl‐L‐methionine‐L‐leucine‐L‐phenylalanine and phorbol myristate acetate) and >95% viability (ethidium bromide/acridine orange stain)in vitro. Total thoracic radioactivity increased significantly from baseline in response to PAF with a slight tachyphylaxia in the neutrophil‐accumulation after a repeat PAF infusion. The highest ratios of radiolabel (tissue/blood) were found in the spleen >>liver>lung.
Platelet activating factor induced respiratory mucosal damage
Authors: Hisamatsu Ken‐ichi , Ganbo Tetsuya , Nakazawa Tsutomu , Murakami Yoshihiko 
Published: February 2007

AbstractHuman sinus mucosal specimens from eight normal individuals were exposed to platelet activating factor (PAF) at concentrations ranging from 10−6 M to 10−11 M in a humidified CO2 chamber at 37°C. The mucosal surface of the specimens was recorded on video tapes and magnified 2,500 times on a 19‐inch television (TV) monitor. Ciliary activity of each ciliated cell was photoelectrically measured on the TV monitor in real time. PAF induced mucosal damage which resulted in a coarse profile including ciliostasis and exfoliation of epithelial cells. The length of the incubation period in which the initial coarse profile occurred on the mucosal surface inversely correlated with the concentration of exposed PAF ranging from 10−6 M to 10−10 M with r=−0.712 (p<2×10−4). Both the control medium and 10−8 M lysoPAF showed no effect on ciliary activity or mucosal surface alteration even after 24 hr of exposure. Significant ciliary inhibition was noted after 6 hr of exposure to PAF at concentrations of 10−8 M and 10−10 M (p<0.05). After 10 hr of exposure, significant ciliary inhibition (p<0.01) was noted at all concentrations. Inhibition occurred in a time‐ and dose‐dependent manner. The length of the incubation period in which initial ciliostatis occurred and the level of PAF concentration showed an inverse correlation with r=−0.918 (p<10−6). These results indicate that PAF is cytotoxic to human respiratory mucosa.
Effects of PAF antagonists on renal vascular escape and tachyphylaxis in perfused rabbit kidney
Authors: Ferreira M. G. , Braquet P. , Fonteles M. C. 
Published: February 2007

AbstractRenal vascular escape is a physiological phenomenon of adaptation that occurs in vascular smooth muscle. It has been described in many preparations subjected to electrical stimulation or treated with vasoactive agents, such as noreprinephrine, angiotensin and vasopressin. We have recently demonstrated that a naturally occurring ginkgolide (BN 52021), which is a PAF antagonist, was able to block norepinephrine‐induced escape in perfused rabbit kidney. In the present work other PAF antagonists, such as the ginkgolides BN 52022 and BN 52024, and the synthetic compounds 48740 RP and WEB 2086, were tested. Their effects on renal vascular escape, perfusion pressure and tachyphylaxis were evaluated. They all were shown to block the escape. Among the ginkgolides, BN 52024 is generally recognized as one of the weaker PAF antagonists. However, in spite of this, BN 52024 was able to significantly and simultaneously block renal vascular escape and tachyphylaxis in perfused rabbit kidney infused with norepinephrine.
Differential effect of a PAF antagonist CV‐3988 on active and passive anaphylactic shock in various mouse strains
Authors: Arimura Akinori , Harada Minoru 
Published: February 2007

AbstractTo define the role of platelet‐activating factor (PAF) in anaphylactic shock in the mouse, the suppressive effect of CV‐3988, a PAF antagonist, on active and passive anaphylactic shock was studied. Various mouse strains treated or not treated withBordetella pertussis (B. pertussis) were used. We found that the effect of CV‐3988 on anaphylactic shock in the mice that were actively sensitized with bovine serum albumin plusB. pertussis differed markedly according to mouse strain. CV‐3988 suppressed the anaphylactic shock in C3H/He and CBA/JN mice at a low dose of 3 mg/kg, whereas antagonists to other mediators such as histamine, serotonin, thromboxane A2 and leukotrienes did not show a suppressive effect. This suggests that PAF plays a major role in anaphylactic shock in these strains. On the other hand, CV‐3988 did not suppress active anaphylactic shock in cataract Shionogi (CTS), NOD and DS strains even at a high dose of 30 mg/kg, which could be interpreted to suggest that PAF is not active in these strains. However, this possibility was ruled out based on the similar results obtained in passive anaphylactic shock and PAF‐induced shock in these mice. Passive anaphylactic shock in CTS mice mediated by IgG1 antibody was markedly suppressed by CV‐3988 but not at all by antagonists to other mediators. Furthermore, the suppressive action of CV‐3988 against passive anaphylactic shock, and PAF‐induced shock was greatly attenuated when the mice were pretreated withB. pertussis. From these results, the conclusion can be drawn that PAF is the main mediator of active and passive anaphylactic shock in the mouse in general, even though the effect of CV‐3988 differs depending on the mouse strain and on whether or notB. pertussis treatment is used.
The effect of tallow‐based detergents on anaerobic digestion
Authors: Maurer E. W. , Cordon T. C. , Weil J. K. , NuɁez‐Ponzoa M. V. , Ault W. C. , Stirton A. J. 
Published: February 2007

AbstractEight anionic detergents from three general classes (alcohol sulfates,a‐sulfo fatty acid esters and alkylbenzenesulfonates were tested for biodegradability under anaerobic conditions of sludge digestion. The alcohol sulfates were found to be readily and completely degraded. Thea‐sulfo fatty acid esters did not degrade but had no adverse effect on bacteriological digestion while the alkylbenzenesulfonates used for control purposes did not degrade and disrupted the normal digestion process.Preliminary lysimeter studies showed that sodium isopropyla‐sulfostearate is completely degraded, linear alkylbenzenesulfonate 83%, and ABS 35%.
Plasticizing properties of esters of monohydric alcohols and tall oil fatty acids
Authors: Bauer S. T. , Hastings Randall 
Published: February 2007

AbstractTall oil fatty acid esters prepared as intermediates in an epoxy ester plasticizer program were similarly evaluated as low‐temp plasticizers in polyvinyl chloride resins. Performance characteristics as primary and secondary plasticizers in polyvinyl sheeting and extruded tapes were determined on esters from methyl to heptadecyl tallate.Results indicate that these materials impart low‐temp properties which would make them of value as low‐cost plasticizers in extruded and molded products where light and heat stability are not primary factors.
A study of the influence of storing wood on the yield and quality of tall oil
Authors: Cowart Walter , Tate D. C. , Churchill John 
Published: February 2007

AbstractIn 12 weeks of storage time pine roundwood lost approximately 11% in tall oil yield, while for the same length of time purchased slabwood chips (pine) lost 64%. Most of the loss in yield occurred within six weeks. The purchased chips lost more tall oil yield in one week than the roundwood in 12 weeks.The loss in yield from the roundwood was due entirely to the loss in yield of fatty acids. The loss in yield in the purchased slabwood chips was due predominantly to the loss in yield in fatty acids; however, there was, in addition, a small loss in resin acids, and a very small loss in unsaponifiables.As for tall oil quality, by the end of 12 weeks of storage the acid number of tall oil from both roundwood and purchased chips had dropped below 160.In correlating the yield of tall oil from the wood extractions with the yield of tall oil from the black liquor from digester cooks, it appears that on the average about 80% to 88% of the extracted tall oil can be found in the black liquor.
Determination of polar lipids: Quantitative column and thin‐layer chromatography
Authors: Rouser George , Kritchevsky Gene , Galli Claudio , Heller Dorothy 
Published: February 2007

AbstractThe structures of the polar lipid classes of plants and animals are presented, their nomenclature discussed, and suggestions are presented for clarification of nomenclature. The three general types of quantitative chromatographic procedures (column chromatography, thin‐layer chromatography, and combinations of column and thin‐layer chromatography) available for polar lipids are reviewed and a new quantitative two‐dimensional thin‐layer chromatographic procedure is presented. Useful quantitative procedures employing columns of cellulose, silicic acid, silicic acid mixed with silicate, magnesium silicate, and ion exchange celluloses are presented. New findings with diethylaminoethyl cellulose columns are described. New quantitative procedures employing silicic acid, magnesium silicate, or diethylaminoethyl cellulose column chromatography with quantitative thin‐layer chromatography are described.
Oil fixation in cottonseed meals
Authors: Szutowicz Walter 
Published: February 2007

AbstractA fraction of the lipid material in cottonseed is fixed in the meal during processing in an oil mill and cannot be extracted with petroleum ether. This relatively unknown and unrecognized 舠fixed oil舡 fraction may vary in quantity in different meals. A procedure is described for the quantitative estimation of the fatty acids from this fraction in previously extracted cottonseed meal.
Cultural practices for lesquerella production
Authors: Roseberg Richard J. 
Published: February 2007

AbstractWhileLesquerella fendleri has good potential of becoming a domestic, water‐efficient source of hydroxy fatty acids in the United States, little research has been done outside of Arizona to determine its environmental response and cultural requirements. This study examined the effects of planting date, irrigation rate and fertilizer on growth and yield in Oregon, and it also evaluated tolerance to existing herbicides as a first step in developing cost‐effective weed control programs. An October planting failed, while a March planting generally out‐yielded a May planting. Seed yield was maximized at irrigation plus precipitation in the range of 959 to 1111 mm. Fertilizer response was indefinite, although response to phosphorus sometimes occurred. Herbicides with excellent potential include trifluralin and benefin pre‐plant incorporated, and fluazifop post‐emergent. Potential herbicides also include pendimethalin preemergent, and oxyfluorfen, dicamba and clopyralid postemergent. In addition to further studies on herbicide, irrigation, fertilizer and planting date effects, studies to optimize other cultural practices (e.g., row width, plant density, seed source, varietal development) that increase oil yield and quality while reducing input cost are required if lesquerella production is to occur in Oregon.
Prepress solvent extraction of cuphea seed
Authors: Carlson Kenneth D. , Kleiman Robert , Pavlik Robert P. 
Published: February 2007

AbstractSimulation of commercial processing of Cuphea seed to obtain needed quantities of oil and meal was accomplished with pilot facilities. Cuphea seed was conditioned in a single‐deck cooker. Cooked seed was pressed with a mechanical screw with two‐speed shaft, variable‐speed drives and a four‐section cage with cored sleeves. A feed rate of 22 kg seed/h and a feed screw‐to‐main shaft ratio of 2:1 gave good press cake with 8.1% residual oil. Press cake was extracted in a batch‐type modular extraction pilot plant. Miscella stages were sequentially pumped through the beds, followed by hexane rinses. Spent cake was desolventized and toasted, and full miscellas were stripped to recover the crude oil. The finished Cuphea meal had only 0.30–0.55% residual oil. Thus, conditioned Cuphea seed was easily pressed without prior flaking to acceptable cakes, and conditions simulating commercial solvent extraction efficiently removed residual cake oil.
Improved high‐performance liquid chromatography of vitamin E vitamers on normal‐phase columns
Authors: Shin Tai‐Sun , Godber J. Samuel 
Published: February 2007

AbstractA method is described for improving column stability and reproducibility for analysis of vitamin E vitamers on normal‐phase high‐performance liquid chromatography columns with isooctane/ethyl acetate/acetic acid/2,2‐dimethoxypropane (98.5:0.9:0.85:0.1) mobile phase. Acetic acid in the mobile phase reduced retention times of vitamin E vitamer and increased column stability. A small concentration of 2,2‐dimethoxypropane, which reacts with water to form acetone and methanol, reduced the need for column regeneration and stabilized retention times.
Model simulation of soil carbon dynamics with stand development in Japanese cedar (Cryptomeria japonica) plantations
Authors: Shuto Katsuyuki , Nakane Kaneyuki 
Published: January 2007

AbstractSoil carbon cycling in Japanese cedar plantations after clear‐cutting over time was calculated with and without consideration of plantation management (pruning and thinning) using a mathematical model. The model employed a daily time step and used daily air temperature and observed precipitation near the plantations. The results of these calculations of above‐ground biomass, carbon flow and accumulation were compared with the field observations reported by Shutou and Nakane (Ecol Res 19:233–244, 2004) observed in the Hiroshima prefecture. For example, the carbon accumulation and total soil respiration rate calculated with the inclusion of plantation management for a 60‐year‐old stand were 104 and 4.8 t C ha−1year−1, compared with a field observation of 110 and 4.5 t C ha−1year−1, respectively. The results calculated for carbon flow and accumulation were not significantly different from the field observations, assessed using one‐way analysis of variance (P > 0.05), and the mean relative errors were very small (e.g., the maximum was 0.05). Consequently, it is suggested that the dynamics of carbon cycling following clear‐cutting of a Japanese cedar plantation can be simulated realistically using these calculations with and without consideration of plantation management. Moreover, it is possible that the calculation without consideration of plantation management can yield the change of carbon cycling over time, even if the history of forest management in the plantations is unknown. It is expected that this study will contribute to the development of a more versatile model.
Effects of different components of diversity on productivity in artificial plant communities
Authors: Jiang Xiao Lei , Zhang Wei Guo , Wang Gang 
Published: January 2007

AbstractIn an experiment on artificial plant communities, the effects of three components of plant diversity—plant species diversity, plant functional group diversity and plant functional diversity—on community productivity and soil water content were compared. We found that simple regression analysis showed a positive diversity effect on ecosystem processes (productivity and soil water content). However, when three components of diversity were included in the multiple regression analyses, the results showed that functional group diversity and functional diversity had more important effects on productivity and resource use efficiency. These results suggested that, compared with species number, functional differences among species and the range of functional traits carried by plants are the basis of biodiversity effects on ecosystem functioning. These diversity effects of increasing functional group diversity or functional diversity were likely because species differing greatly in size, life form, phenology and capacity to capture and use resources efficiently in diverse communities realize complementary resource use in temporal, spatial, and biological ways.
Soil and vegetation nutrient response to bison carcasses in Białowieża Primeval Forest, Poland
Authors: Melis Claudia , Selva Nuria , Teurlings Ivonne , Skarpe Christina , Linnell John D. C. , Andersen Reidar 
Published: January 2007

AbstractUngulate carcasses can have important effects on the surrounding soil and vegetation. The impact of six carcasses of European bison (Bison bonasus) was investigated for the first time in a natural temperate forest (Białowieża, Poland) by measuring soil and plant nutrient concentrations along a gradient extending from the centre of each carcass. Calcium concentration and pH were found to be higher at the centre of the carcass, decreasing towards the periphery. This effect lasted up to 7 years after the death of the animal. The concentration of most nutrients in the soil and plants varied irregularly, suggesting an effect of the carcass at its centre but the absence of a clear pattern of variation along the gradient. Concentrations of NO3− in the soil differed only at the 1‐year old carcass, suggesting a fast turnover of nitrate in temperate forests. Our results show that the effects of large herbivore carcasses on soil and plant nutrient concentrations are not easily detectable in a temperate forest as in more homogeneous habitats, such as tundra and prairie. This may be due to the high activity of scavengers and nutrient recycling in the study area, but it may also be a consequence of a more complex and patchy interaction between nutrient availability and other limiting factors in temperate forests.
Stochastic dynamics in exotic and native blowflies: an analysis combining laboratory experiments and a two‐patch metapopulation model
Authors: Serra Hiraldo , da Silva Izabel Cristina Rodrigues , Mancera Paulo Fernando de Arruda , Faria Lucas Del Bianco , Von Zuben Cláudio José , Von Zuben Fernando José , dos Reis Sérgio Furtado , Godoy Wesley Augusto Conde 
Published: January 2007

AbstractIn this study we explored the stochastic population dynamics of three exotic blowfly species,Chrysomya albiceps,Chrysomya megacephalaandChrysomya putoria, and two native species,Cochliomyia macellariaandLucilia eximia, by combining a density‐dependent growth model with a two‐patch metapopulation model. Stochastic fecundity, survival and migration were investigated by permitting random variations between predetermined demographic boundary values based on experimental data.Lucilia eximiaandChrysomya albicepswere the species most susceptible to the risk of local extinction.Cochliomyia macellaria,C. megacephalaandC. putoriaexhibited lower risks of extinction when compared to the other species. The simultaneous analysis of stochastic fecundity and survival revealed an increase in the extinction risk for all species. When stochastic fecundity, survival and migration were simulated together, the coupled populations were synchronized in the five species. These results are discussed, emphasizing biological invasion and interspecific interaction dynamics.