bluuebunny/crossref_metadata_2025 huggingface dataset:
Cation exchange hysteresis scanning curves: mathematical description and interpretation
Authors: VERBURG K. , BAVEYE P.
Published: August 2005

Cation exchange reactions in clays and soils have repeatedly been shown in the literature to be hysteretic during typical laboratory experiments. Yet all existing models of solute transport in soils and aquifers assume these reactions to be thermodynamically reversible. To remedy this situation a mathematical description of cation exchange hysteresis is needed. In the present research isotherms were obtained for a K‐Mg exchange on Camp Berteau montmorillonite. Scanning curves were also measured, corresponding to arbitrary reversals of the direction of the exchange reactions. Three different Preisach‐hysteresis models were used to describe the scanning curves. The fit of each hysteresis model to the experimental observations was analysed in terms of the features of the model itself and, from a physical viewpoint, in terms of a recently proposed conceptual model of cation exchange hysteresis.
Influence of gravimetric water content and bulk density on the dielectric properties of soil
Authors: PERDOK U.D. , KROESBERGEN B. , HILHORST M.A.
Published: August 2005

Moisture content and bulk density largely characterize physical and mechanical soil status and behaviour. A nondestructive determination of these soil properties is essential. Time domain reflectometry (TDR), although widely accepted for determination of volumetric water content, θ, has its limitations, and recently a frequency domain (FD) sensor has been developed and tested. An equation relating relative permittivity, ɛ′, to gravimetric water content, w, and bulk density, p, was established for three soil types (sand, sandy loam and clay). If ɛ′ and w are known, our model can be used to calculate bulk density and associated volumetric water content, θ, keeping in mind that θ= pw. Utilization is found in long‐term monitoring of moisture fluctuations or short‐term detection of traffic‐induced soil compaction.
Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology
Authors: LE BISSONNAIS Y.
Published: August 2005

Crusting and erosion of cultivated soils result from aggregate breakdown and the detachment of soil fragments by rain, and the susceptibility of soil to these processes is often inferred from measurements of aggregate stability. Here, theories of aggregate breakdown are reviewed and four main mechanisms (i.e. slaking, breakdown by differential swelling, mechanical breakdown by raindrop impact and physico–chemical dispersion) are defined. Their relative importance depends on the nature of the rain, as well as on the soil's physical and chemical properties. The relations between aggregate breakdown, crusting and water erosion are analysed, and existing methods for the assessment of aggregate stability are reviewed. A unified framework for the measurement of aggregate stability is proposed to assess a soil's susceptibility to crusting and erosion. It combines three treatments having various wetting conditions and energies (fast wetting, slow wetting, and stirring after pre‐wetting) and measures the resulting fragment size distribution after each treatment. It is designed to compare different soils, or different climatic conditions for a given soil, not to compare time‐dependent changes in that soil.
Lattice–gas approach to surface runoff after rain
Authors: GARCIA‐SANCHEZ L. , DI PIETRO L. , GERMANN P.F.
Published: August 2005

We simulated the distribution of water flowing over the soil surface in small plots using a lattice‐gas approach. The numerical lattice‐gas algorithm consists in simulating a fluid as a finite set of particles which move in a discrete lattice obeying deterministic rules. With this technique, complex boundary conditions and transient flow regimens are handled with ease. The amount of depressional storage and the onset of runoff were considered as functions of rainfall intensity, surface roughness, slope angle and infiltration dynamics. Rainfall was simulated by spherical raindrops of fixed diameter, which were generated by a space and time Poisson process of constant intensity. The effect of infiltration on surface flow was simulated by removing liquid particles at the solid surface with a chosen rate function. Depressional storage and runoff then result from the intrinsic hydrodynamic behaviour of the model under the imposed rainfall, infiltration rate and surface geometry. Results of numerical experiments are presented. They show that the lattice‐gas approach is well‐adapted for simulating the formation of excess water and the roles of roughness and slope in attenuating runoff for any arbitrary complex surface geometry.
Improving the kriging of a soil variable using slope gradient as external drift
Authors: BOURENNANE H. , KING D. , CHÉRY P. , BRUAND A.
Published: August 2005

Universal kriging with a topographic variable used as external drift was compared with ordinary kriging, ordinary kriging with external drift, and universal kriging for predicting the thickness of a superficial deposit on part of the Beauce of central France. Thickness was recorded at 62 sites and at another 25 sites to obtain a sample for validation. A Digital Elevation Model (DEM) was computed from 484 sites where relative elevation was measured. The slope gradient which is significantly correlated to thickness was used as an external drift variable for kriging thickness. The sample for validation was used for testing the four prediction methods. In testing each of the methods, two indices were computed from the validation sample (observed data) and predicted values. These two indices are the mean error (ME) and the root mean square error (RMSE). The results show that universal kriging with the slope gradient used as external drift was more precise than the other kriging methods. Further analysis based on the mean ranks of performance confirmed these results.
Influence of soil properties and soya bean cropping history on the Bradyrhizobium japonicum population in some French soils
Authors: REVELLIN C. , PINOCHET X. , BEAUCLAIR P. , CATROUX G.
Published: August 2005

As French soils are naturally free of Bradyrhizobium japonicum, soya beans planted into new areas must be inoculated with this bacterium. Although, the B. japonicum inoculum can survive in soils for long periods of time even in the absence of a soya bean crop, re–inoculation may increase nodulation and grain yield. Thus, populations of B. japonicum can fall below optimum for plant growth. To identify the soil properties controlling survival of the inoculated bacteria samples of soil were collected from 52 sites from France that had previously grown soya beans. The samples were analysed for some physical and chemical characteristics and the B. japonicum population counted. The soil's CaCO3 content was the main factor affecting survival. The average B. japonicum numbers (per g soil) were 80 for calcareous soils and 15000 for non–calcareous soils. In the latter, silt and sand contents were correlated with the numbers of B. japonicum. The cropping frequency of soya bean and the time since the crop was last grown were other factors affecting Bradyrhizobium populations. Thus, there is a probability of enhancing economic benefit for farmers with re–inoculation of soya bean in calcareous and sandy soils.
Distribution of cation exchange capacity between organic matter and mineral fractions in acid forest soils (Vosges mountains, France)
Authors: TURPAULT M.‐P. , BONNAUD P. , FIGHTER J. , RANGER J. , DAMBRINE E.
Published: August 2005

The cation exchange capacity (CEC) of 18 samples (<2 mm) of five acid soils developed on granite or gneiss was measured before and after H2O2 treatment from pH‐unbuffered extraction solution (1 N KCl). The pH in water of the soils ranged from 3.4–4.7. The samples were separated into seven fractions (<2 μm, 2–20 μm, 20–50 μm, 0.05–0.2 mm, 0.2–0.5 mm, 0.5–1 mm and 1–2 mm) and the CEC of each measured. Thus the contribution of each size fraction and of organic matter to the CEC was obtained. From CEC measurements on the different fractions and particle size distribution data, a balance calculation was carried out to verify the methodology. According to the hypotheses used and soil characteristics, the CEC of organic matter was found to vary from 35 to 165 cmolc kg−1 and so represented from 10 to 85% of the total soil CEC in the upper soil horizons. In these sandy soils developed on granite or gneiss which were frequently affected by hydrothermal alteration, the CEC of silt and sand fractions was large. It can represent from 35 to 80% of the total soil mineral CEC. The specific contribution of the 0.2–2 mm fraction can reach 50% of the total soil mineral CEC with values ranging from 0.5–5.2 cmolc kg−1. The mineralogical description showed that hydrothermal white micas and neoformed smectites (precipitated during weathering) were present in all the fractions even in the coarsest ones. In some subsoils, albite grains containing smectite have a CEC as large as 21 cmolc kg−1. This study shows that the CEC of acid soils was not always located in the organic matter and in the clay fraction. The sand fraction can contribute substantially to the soil CEC.
Side‐effects of herbicides on the size and activity of the soil microflora: DNOC as a test case
Authors: ROUARD N. , DICTOR M.‐C. , CHAUSSOD R. , SOULAS G.
Published: August 2005

Recent advances in measuring soil microbial biomass by chloroform fumigation–extraction (CFE) and microbial heterotrophic activity interpreted by quantitative concentration–activity relations (QCAR) have renewed interest in assessing side–effects of agricultural chemicals on soil microorganisms. We have studied the effects of a herbicide, 4,6‐dinitroorthocresol (DNOC), taken as a test chemical, on the rate of microbial carbon turnover and the size of the soil microbial biomass. We used the CFE technique in combination with in‐situ labelling of the soil biomass. Exposure of prelabelled soil samples to the herbicide resulted in a significant increase in 14CO2 production during which the radioactive carbon content of the microflora decreased exponentially without apparent reduction in the size of the biomass. The extra production of 14CO2 by DNOC‐treated soil over control, or carbon‐enriched soil, is the expression of an increased rate of endogenous metabolism to compensate for shortage in energy caused by a decoupling of ATP generation at the oxidative phosphorylations level by the DNOC. To assess the influence of DNOC on soil microbial communities we also compared the advantages of short‐term respirometric tests with those resulting from application of heterotrophic activity measurements in connection with QCAR. Both procedures detected modifications in the metabolic behaviour of soil microorganisms when faced with chemical stress. Short‐term respirometric tests showed that DNOC causes a decrease in the respirometric activity of the soil microflora. Measuring heterotrophic activity also makes it possible to interpret microbial responses in terms of changes in the physiological traits of the microbial communities. DNOC provokes an apparent enrichment in microorganisms with a smaller saturation constant, Km and, as a consequence, a greater affinity for carbon substrates.
Influence of the nature of soil organic matter on the sorption‐desorption of 4‐chlorophenol, 2,4‐dichlorophenol and the herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D)
Authors: BENOIT P. , BARRIUSO E. , HOUOT S. , CALVET R.
Published: August 2005

The sorption–desorption properties of three organic pollutants, 4‐chlorophenol (4‐CP), 2,4‐dichlorophenol (2,4‐DCP) and the herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D) on soil organic matter (SOM) were studied using kinetic and equilibrium measurements in aqueous suspensions. Chestnut wood, wheat straw, Kraft lignin, composted straw and a soil humic acid were chosen as sorbents to model different states of humification. Physico–chemical characterization using chemical fractionation, potentiometric titration and IR spectroscopy was done on all sorbents. The microbial biomass, sizes of total bacterial and fungal microflora and phenoloxidases activities were determined for the plant materials. The irreversibility of sorption was revealed by the desorption isotherms. Only a small proportion of 2,4‐D, which has little affinity for the fresh organic materials, was desorbed. Sorption of 2,4‐DCP was strong on straw but was reversible to a large extent, indicating weaker interactions. By comparison, the sorption of 4‐CP was significantly less reversible. Thus, the nature of SOM and the properties of the chemicals strongly influenced the extent of sorption and the type of interactions, and it controlled subsequent desorption and possible transformation of the sorbed species.
Micro‐scale variation of solid‐phase properties and soil solution chemistry in a forest podzol and its relation to soil horizons
Authors: GÖTTLEIN A. , STANJEK H.
Published: August 2005

In order to evaluate micro‐scale heterogeneities 55 micro suction cups were placed in an array at 15 mm intervals in a profile face of a cambic podzol. The chemistry of soil solution (mineral anions, pH, UV absorption as a measure for DOC) was compared with solid‐phase properties from soil samples (2 cm3 volume), which had surrounded the suction cups. Sequential extraction techniques (water, NF4Cl, hydroxylamin‐hydrochloride, citrate‐bicarbonate, oxalate, dithionite‐citrate‐bicarbonate) and base titrations were applied to characterize the solid phase. Although the average soil solution concentrations between horizons often differed significantly, the spatial distributions of pH and SO42− did not correlate with soil horizon borders. Even if concentration isolines and soil horizon borders were parallel, marked concentration gradients could be observed within individual soil horizons. The less intense the interaction between solute ion and soil matrix, the greater was the variation in solution concentration within a soil horizon. For the soil solid phase only a weak correlation of slow buffer reactions to soil horizons was found. The distribution of extractable Fe and Al was typical for a podzol profile, however, with very steep gradients within single soil horizons. Except for pH, which was related mainly to citrate‐bicarbonate extractable aluminium, no solid‐phase characteristic showed a clear correlation with soil solution chemistry.
Effects of crystallinity of goethite: I. Preparation and properties of goethites of differing crystallinity
Authors: STRAUSS R. , BRÜMMER G.W. , BARROW N.J.
Published: August 2005

We prepared five samples of pure goethite and three samples of aluminous goethite with mole fractions of aluminium ranging from 0·05 to 0·20. One of the samples of pure goethite was repeatedly heated in an autoclave at 150°C. We studied the samples using transmission electron microscopy and XRD and we measured the surface area (BET), rate of dissolution of the samples in acid, the surface charge in four concentrations of sodium nitrate from pH 4–10, and the sorption of calcium and chloride from a dilute solution of calcium chloride. Surface areas ranged from 18 to 132 m2 g−1. The BET adsorption‐desorption isotherms had hysteresis loops which increased as the surface area increased. These showed that there were pores present with diameters smaller than 2 nm and that the number of pores increased as the surface area increased. All samples of goethite showed typical X‐ray diffraction patterns but with peak heights decreasing, and width increasing, as surface area increased. Mean coherence lengths, as determined by XRD line broadening, were smaller than those determined by transmission electron microscopy. This was because each crystal was composed of several domains, and the XRD data reflect the size of the domains. Heating one of the goethite samples in an autoclave caused most of the domains to coalesce and slightly decreased the surface area. As the surface area of the eight goethite samples increased, the mean coherence length in the direction of the a, b and c axes decreased. The better crystallized samples dissolved more slowly in acid and the dissolution curves were sigmoid because the acid was able to penetrate between the domains allowing access to a larger surface area and consequently accelerated dissolution. The points of zero charge increased with increasing surface area of the goethite. The charge carried by the goethite at pH values distant from the point of zero charge increased as the surface area increased. This may indicate movement of protons or hydroxyl ions into pores or other defects in the crystal. The effects of pH and of salt concentration on surface charge were closely described by the variable‐charge/variable‐potential model. This model also closely described adsorption of Ca2+ and Cl− from calcium chloride solutions requiring only the allocation of constants for these ions. The substitution of aluminium for iron did not affect the charge properties of goethite.
Reduction of Cr(VI) by soil humic acids
Authors: WITTBRODT PAUL R. , PALMER CARL D.
Published: August 2005

The rate of hexavalent chromium reduction by a soil humic acid (SHA) was investigated in aqueous solutions where concentrations of Cr(VI), H+, and SHA were independently varied. Rate experiments were done with a large excess of SHA over Cr(VI). Rates of reduction depend strongly on [H+], increasing with decreasing pH. Typical Cr(VI)‐SHA reactions display a nonlinear reduction of Cr(VI) with time that cannot be modelled with simple first‐ or second‐order rate equations. An empirical rate equation is developed for Cr(VI)‐soil humic acid reactions over a range of experimental conditions. The model is in part based on a reactive continuum concept developed for soil fulvic acids. The rate equation describing Cr(VI) reduction by SHA is:
R= ‐(k0+k[H+]1/2)[HCrO4−]1/2Xe−1,
where k0 is (8·3 ± 1·2) × 10−12, s−1k is (2·04 ± 0·05) × 10−9 l1/2 mol−1/2 s−1, and Xe is the equivalent fraction of SHA oxidized. The rate equation adequately models Cr(VI) reduction in an experiment with [Cr(VI)]0 four times greater than the maximum concentration used in its derivation. Cr(VI) reduction at pH 3 by two other SHAs can also be modelled using the rate equation. The difference between the rate coefficients for the humic acid and the fulvic acid from the same soil was greater than the difference in the rate coefficients for humic acids from different soils.
Fate of carbon and nitrogen in water‐stable aggregates during decomposition of 13C15N‐labelled wheat straw in situ
Authors: ANGERS D.A. , RECOUS S. , AITA C.
Published: August 2005

When incorporated in soil, plant residues and their decomposition products are in close contact with mineral particles with which they can be bound to form aggregates. We measured the incorporation of carbon (C) and nitrogen (N) derived from crop residues in water‐stable aggregate fractions of a silty soil in a field experiment in Northern France using 13C15N‐labelled wheat straw (Triticum aestivum L.). Soil samples were taken seven times for 18 months and separated into slaking‐resistant aggregate size fractions which were analysed for total C and N contents, and 13C and 15N enrichments. During the early stages of decomposition (approximately 200 days), the enrichment of 13C increased rapidly in the macro aggregates (> 250 pm) but decreased thereafter. The macro aggregates represented only < 20% of the soil mass and at any one time, they accounted for <25% of the residual 13C in the soil. The proportion of 13C recovered in the <50‐μm and 50–250‐μm fractions increased during decomposition of the residues; at day 574, the 50–250‐μm fraction accounted for close to 50% of the residual 13C. A greater proportion of 15N than 13C was recovered in the <50‐μm fraction. The results indicate that during decomposition in soil, C and N from crop residues become rapidly associated with stable aggregates. In this silty soil the 50–250‐μm stable aggregates appear to be involved in the storage and stabilization of C from residues.
Inhibiting Biosynthesis and/or Metabolism of Progestins in the Ventral Tegmental Area Attenuates Lordosis of Rats in Behavioural Oestrus
Authors: Petralia S. M. , Jahagirdar V. , Frye C. A.
Published: August 2005

In the ventral tegmental area (VTA), lordosis of rats is facilitated by 5α‐pregnan‐3α‐ol‐20‐one (3α,5α‐THP). Central 3α,5α‐THP results from metabolism of peripheral progesterone, from the ovaries and/or adrenals, by sequential enzymatic activity of 5α‐reductase and 3α‐hydroxysteroid oxidoreductase (3α‐HSOR). In addition, in glial cells, cholesterol is converted into pregnenolone by the P450 side‐chain cleavage enzyme (P450scc), which is then metabolized to progesterone by 3β‐hydroxysteroid dehydrogenase, and subsequently reduced to 3α,5α‐THP. We hypothesize that, in the VTA, formation of 3α,5α‐THP by both metabolism and biosynthesis is necessary for facilitation of lordosis of female rats. In Experiment 1, naturally‐receptive rats received bilateral VTA infusions of a P450scc inhibitor, digitoxin (1 µg/side); a 5α‐reductase inhibitor, finasteride (10 µg/side); digitoxin (1 µg/side) + finasteride (10 µg/side); or vehicle and were tested 3 h later for lordosis. In Experiment 2, the effects of VTA infusions of digitoxin, finasteride, digitoxin + finasteride, or vehicle on lordosis and midbrain and plasma 3α,5α‐THP levels were examined. In Experiment 3, we investigated whether infusions of 3α,5α‐THP to the VTA reinstated lordosis and midbrain 3α,5α‐THP levels following administration of inhibitors. VTA infusions of digitoxin, finasteride, or digitoxin + finasteride, significantly and similarly reduced lordosis and midbrain, but not plasma 3α,5α‐THP levels, compared to vehicle. Following receipt of inhibitor infusions, 3α,5α‐THP to the VTA restored lordosis and midbrain 3α,5α‐THP levels. These data suggest that, in the VTA, both central biosynthesis of progesterone and metabolism of progesterone (from central and/or peripheral sources) to 3α,5α‐THP are important for mediating lordosis of rats.
Interactions Between Kinases and Phosphatases in the Rapid Control of Brain Aromatase
Authors: Balthazart J. , Baillien M. , Ball G. F.
Published: August 2005

Aromatization of testosterone into oestradiol plays a key role in the activation of male sexual behaviour in many vertebrate species. Rapid changes in brain aromatase activity have recently been identified and the resulting changes in local oestrogen bioavailability could modulate fast behavioural responses to oestrogens. In quail hypothalamic homogenates, aromatase activity is down‐regulated within minutes by calcium‐dependent phosphorylations in the presence of ATP, MgCl2 and CaCl2 (ATP/Mg/Ca). Three kinases (protein kinases A and C and calmodulin kinase; PKA, PKC and CAMK) are potentially implicated in this process. If kinases decrease aromatase activity in a reversible manner, then it would be expected that the enzymatic activity would increase and/or return to baseline levels in the presence of phosphatases. We showed previously that 0.1 mM vanadate (a general inhibitor of protein phosphatases) significantly decreases aromatase activity but specific protein phosphatases that could up‐regulate aromatase activity have not been identified to date. The reversibility of aromatase activity inhibition by phosphorylations was investigated in the present study using alkaline and acid phosphatase (Alk and Ac PPase). Unexpectedly, Alk PPase inhibited aromatase activity in a dose‐dependent manner in the presence, as well as in the absence, of ATP/Mg/Ca. By contrast, Ac PPase completely blocked the inhibitory effects of ATP/Mg/Ca on aromatase activity, even if it moderately inhibited aromatase activity in the absence of ATP/Mg/Ca. However, the addition of Ac PPase was unable to restore aromatase activity after it had been inhibited by exposure to ATP/Mg/Ca. Taken together, these data suggest that, amongst the 15 potential consensus phosphorylation sites identified on the quail aromatase sequence, some must be constitutively phosphorylated for the enzyme to be active whereas phosphorylation of the others is involved in the rapid inhibition of aromatase activity by the competitive effects of protein kinases and phosphatases. Two out of these 15 putative phosphorylation sites occur in an environment corresponding to the consensus sites for PKC, PKA (and possibly a CAMK) and, in all probability, represent the sites whose phosphorylation rapidly blocks enzyme activity.
Developmental Changes in GABAA Receptor Subunit Composition Within the Gonadotrophin‐Releasing Hormone‐1 Neuronal System
Authors: Temple J. L. , Wray S.
Published: August 2005

It is becoming increasingly evident that GABA plays an important role in the regulation of gonadotrophin‐releasing hormone (GnRH)‐1 neurones via the GABAA receptor. The aim of the present study was to characterise expression of the GABAA receptor within the GnRH‐1 system across development. The expression pattern of five GABAAα subunits and one GABAAβ subunit was first examined within individual GnRH‐1 neurones by the polymerase chain reaction. A significant increase in the expression of GABAAα2 and a significant decrease in the expression of GABAAα6 over time were found. Of the other subunits examined, two (α1 and α3) showed no differences in expression and two (α4 and β3) showed variable low incidence of expression. Given the reciprocal relationship of α2 and α6 expression, we hypothesised that there is a developmental switch in the expression of these subunits in GnRH‐1 neurones. To investigate this hypothesis, single‐ and double‐label immunocytochemistry for GABAAα2 and α6 and GnRH‐1 was performed in tissue from ages E12.5 to adulthood, as well as in nasal explants. We show that GABAAα2 and α6 are present in the GnRH‐1 neuronal system both in vivo and in vitro and that the levels of expression are altered as a function of age.
Chronic Prenatal Ethanol Exposure Alters Glucocorticoid Signalling in the Hippocampus of the Postnatal Guinea Pig
Authors: Iqbal U. , Brien J. F. , Banjanin S. , Andrews M. H. , Matthews S. G. , Reynolds J. N.
Published: August 2005

The present study tested the hypothesis that chronic prenatal ethanol exposure causes long‐lasting changes in glucocorticoid signalling in postnatal offspring. Pregnant guinea pigs were treated with ethanol (4 g/kg maternal body weight/day), isocaloric‐sucrose/pair‐feeding or water throughout gestation, and maternal saliva cortisol concentration was determined 2 h after treatment at different stages of gestation. Electrically‐stimulated release of glutamate and GABA, in the presence or absence of dexamethasone, as well as glucocorticoid and mineralocorticoid receptor mRNA expression, was determined in the hippocampus and prefrontal cortex of adult offspring of treated pregnant guinea pigs. Maternal saliva cortisol concentration increased throughout pregnancy, which was associated with increased foetal plasma and amniotic fluid cortisol concentration. Ethanol administration to pregnant guinea pigs increased maternal saliva cortisol concentration during early and mid‐gestation. In late gestation, ethanol administration did not increase saliva cortisol concentration above that induced by pregnancy. Chronic prenatal ethanol exposure had no effect on stimulated glutamate or GABA release, but selectively prevented dexamethasone‐mediated suppression of stimulated glutamate release, and decreased expression of mineralocorticoid, but not glucocorticoid, receptor mRNA in the hippocampus of adult offspring. These data indicate that maternal ethanol administration leads to excessively increased maternal cortisol concentration that can impact negatively the developing foetal brain, leading to persistent postnatal deficits in glucocorticoid regulation of glutamate signalling in the adult hippocampus.
Detection of improvement in the masticatory function from old to new removable partial dentures using mixing ability test
Authors: ASAKAWA A. , FUEKI K. , OHYAMA T.
Published: August 2005

summary  The aim of this study was to determine the sensitivity of the Mixing Ability Test to detect improvement of masticatory function in subjects on transition from old to new removable partial dentures. Thirty‐two subjects (seven males, 25 females, mean age 65·0 years) with distal extension partially edentulous area in mandible and/or maxilla participated in the study. The following reasons were presented for replacing the old removable partial dentures with new ones: fracture and/or poor fitness of retainers, extraction of abutment teeth, poor fitness of denture base, severe wear of artificial teeth and request for metal base dentures. Masticatory function with old and new removable partial dentures after an adaptation period (mean 27·4 weeks) was evaluated by the Mixing Ability Test. Subjects were asked to masticate five two‐coloured wax cubes with each removable partial denture. Mixing Ability Index was obtained from the colour mixture and shape of the masticated cubes. Wilcoxon signed‐rank test was used to test the difference of Mixing Ability Indexes between old and new removable partial dentures. The mixing ability indexes with new removable partial dentures (mean ± s.d.: 0·70 ± 0·68) was significantly higher (P < 0·001) than those with old removable partial dentures (−0·11 ± 1·13). The results suggest that the Mixing Ability Test was capable of detecting improvement in masticatory function with new removable partial dentures.
Effects of defect configuration, size, and remaining teeth on masticatory function in post‐maxillectomy patients
Authors: KOYAMA S. , SASAKI K. , INAI T. , WATANABE M.
Published: August 2005

summary  The aim of this study was to investigate the correlation between the masticatory function and the maxillary defect configuration, size, and remaining teeth in post‐maxillectomy patients restored with an obturator prosthesis. Fifty consecutive post‐maxillectomy patients (mean age 67·0) participated in this study. The subjects consisted of 26 dentate and 24 edentulous patients. Data were collected from the patients’ clinical records, diagnostic casts, and a questionnaire on masticatory function to evaluate the defect configuration, size, and the masticatory function scores associated with wearing obturator prostheses. The defect size was evaluated by the ratio of defect area to the horizontal impression area. The defect configuration was assessed according to Aramany's classification and separated into unilateral and bilateral defects. The multiple regression analysis and the Mann–Whitney U‐test (P < 0·05) were used to assess statistical significance. The Spearman's correlation coefficient by rank test was also used to detect correlation. The following conclusions were made: (i) The presence of teeth in the maxillary dentition and the different type of the defect configuration had significant correlation with the masticatory function score (r = 0·616). (ii) The masticatory function scores of the subjects differed significantly with the presence of teeth in the maxillary dentition and the different types of defect configurations (P = 0·005, P = 0·002, respectively). (iii) There was significant correlation between the masticatory function score and the size of the defect area in the edentulous group (r = −0·648, P = 0·001). The presence of teeth, the size and configuration of the defect influenced the masticatory function of post‐maxillectomy patients with obturator prostheses.
Flexure deformation in temporomandibular joint disk displacement without reduction may predict treatment outcome
Authors: YOSHIDA H. , HIROHATA H. , ONIZAWA K.
Published: August 2005

summary  To identify whether the direction of disk flexure deformation predicts the prognosis in cases of anterior disk displacement without reduction of painful temporomandibular joint (TMJ), the relationship between the direction of flexure, observed on pseudodynamic magnetic resonance (MR) images, and the outcome of conservative treatment using a flat occlusal splint was analysed in 40 female patients who perceived occasional or constant pain at unilateral TMJ with disk displacement without reduction. From the MR findings, 20 patients were classified as having upward flexure deformation of the disk and 20 as having downward flexure deformation. Patients’ TMJ pain, masticatory muscle pain, amount of maximal mouth opening, and MR findings were evaluated before treatment. All patients were treated with a flat occlusal splint for 6 months. The patients’ signs and symptoms were analysed statistically within each group before treatment and 3 and 6 months afterwards, and were also compared between the upward and downward flexure groups. There was no statistical difference between the groups before treatment, except in the amount of maximal mouth opening and the extent of disk displacement. The upward flexure group had persistent TMJ pain and tendency of delayed alleviation of masticatory muscle pain compared with the downward flexure group, although maximal opening gradually increased in both groups. Thus, the direction of the flexure in deformation of the disk, which can be observed only with pseudodynamic MR imaging, may predict the prognosis of painful disk displacement without reduction following treatment with a flat occlusal splint.
Leukemia‐Derived Dendritic Cells can be Generated from Blood or Bone Marrow Cells from Patients with Acute Myeloid Leukaemia: A Methodological Approach under Serum‐Free Culture Conditions
Authors: Kufner S. , Zitzelsberger H. , Kroell T. , Pelka‐Fleischer R. , Salem A. , De Valle F. , Schweiger C. , Nuessler V. , Schmid C. , Kolb H. J. , Schmetzer H. M.
Published: August 2005

Functional dendritic cells (DC) are professional antigen‐presenting cells (APC) and can be generated in vitro from healthy as well as from leukaemic cells from acute myeloid leukemia (AML) patients giving rise to APC of leukaemic origin‐presenting leukaemic antigens. We describe the generation and characterization of DC from different mononuclear cell (MNC) fractions from 50 AML patients under different serum‐free culture conditions, determine the optimal culture conditions and compare the results with that from 23 healthy donors. In parallel cultures, we compared DC harvests after 7‐ or 14‐day culture, with total or adherent MNC or T‐cell depleted MNC or peripheral blood (PB) or bone marrow‐MNC (BM–MNC), thawn or fresh MNC, in Xvivo or CellGro serum‐free media, ±10% autologous plasma or ±FL. In detail, we could show that AML–DC harvests were higher after 10–14 days culture (healthy DC: 7 days); total or adherent PB or BM–MNC fractions yield comparable DC counts, however, from magnetic cell sorting (MACS)‐depleted MNC fractions or thawn MNC lower DC counts can be generated. Whereas the addition of FL increases the DC harvest, the addition of autologous plasma in many cases has inhibitory influence on DC maturation. CellGro and Xvivo media yield comparable DC counts. Optimal harvest of vital and mature DC from AML samples was obtained with a granulocyte/macrophage‐colony stimulating factor, interleukin‐4, FL and tumour necrosis factor‐α‐containing serum‐free Xvivo medium after 10–14 days of culture (36/26% DC; 38/64% vital DC; 46/51% mature DC were generated from AML/healthy MNC samples). Surface marker profiles (e.g. costimulatory antigen expressing) of DC obtained from AML samples were comparable with that of healthy DC. The leukaemic derivation of AML–DC was demonstrated by the persistence of the clonal cytogenetic aberration in the DC or by coexpression of leukaemic antigens on DC. Autologous T‐cell activation of leukaemia‐derived DC was demonstrated in cases with AML. Autologous T cells proliferate and upregulate DC‐contact‐relevant antigens. We demonstrate that the generation of leukaemia‐derived DC is feasable in AML under serum‐free culture conditions giving rise to DC with comparable characteristics as healthy DC and offering an anti‐leukaemia‐directed immunotherapeutical vaccination strategy in AML.
The Six Mammalian Cell Entry Proteins (Mce3A–F) Encoded by the mce3 Operon are Expressed During In Vitro Growth of Mycobacterium tuberculosis
Authors: Ahmad S. , El‐Shazly S. , Mustafa A. S. , Al‐Attiyah R.
Published: August 2005

The pathogenesis of Mycobacterium tuberculosis is largely due to its ability to enter and survive within human macrophages. The mammalian cell entry (mce)3 operon is one of four homologous mce operons that encodes six putative invasin‐like exported proteins (Mce3A–F), possibly involved in entry and survival of M. tuberculosis inside macrophages. We have recently shown that Mce3A, Mce3D and Mce3E are expressed and elicit antibody responses in a majority of human subjects during natural infection with M. tuberculosis. In this study, we demonstrate the expression of Mce3A–F proteins and their mRNA during in vitro growth of M. tuberculosis. To demonstrate the expression of mce3A–F proteins, the antibodies were raised in rabbits against three pure proteins (Mce3A, Mce3D and Mce3E), and their specificity was checked by immunoblotting with recombinant Mce1A–F proteins encoded by mce1 operon. The antibodies were also generated against all the six Mce3 proteins, which were expressed and purified as fusion proteins with glutathione S‐transferase (GST) as the fusion partner (GST‐Mce3A–F). The antibodies reacted, in each case, with a protein of expected molecular mass (Mr) for the corresponding Mce3 protein in the cell wall fraction but not in the soluble fraction of in vitro‐grown M. tuberculosis cells. The presence of mRNA for mce3A–F genes was also shown by using mce3A–F gene‐specific primers, and total RNA isolated from in vitro‐grown M. tuberculosis cells by reverse transcription‐polymerase chain reaction (RT‐PCR). Pretreatment of the RNA preparation with RNase A abolished amplification in RT‐PCR confirming that mce3A–F mRNA rather than genomic DNA was being amplified. The data show that Mce3A–F encoded by the mce3 operon are expressed during in vitro growth of M. tuberculosis.
Reactivation of Antigen‐Induced Arthritis in Mice by Oral Administration of Lipopolysaccharide
Authors: Yoshino S. , Yamaki K. , Taneda S. , Yanagisawa R. , Takano H.
Published: August 2005

We examined whether oral administration of lipopolysaccharide (LPS) from Escherichia coli reactivated antigen‐induced arthritis (AIA) in mice that is one of models of human rheumatoid arthritis. To induce AIA, mice were immunized by subcutaneous injection of ovalbumin (OVA) emulsified with complete Freund's adjuvant into the base of the tail (day 0) followed by intraarticular injection of OVA on day 21. To investigate the ability of LPS to reactivate AIA, varying doses of LPS were p.o. administered 48 h after the challenge injection. The results showed that administration of LPS was followed by reactivation of AIA in a dose‐related fashion. The reactivation of AIA by LPS was associated with increases in interferon‐γ, interleukin‐1β and tumour necrosis factor‐α. Polymyxin B sulfate given immediately before administration of LPS suppressed the reactivation of AIA. These findings suggest that LPS from intestinal bacteria may play a role in the reactivation of joint inflammation in which immune responses to pathogenic antigens are involved.
The Immunostimulatory Peptide WKYMVm‐NH2 Activates Bone Marrow Mouse Neutrophils via Multiple Signal Transduction Pathways
Authors: Boxio R. , Bossenmeyer‐Pourié C. , Vanderesse R. , Dournon C. , Nüße O.
Published: August 2005

G‐protein‐coupled receptors play a major role in the activation of the innate immune system, such as polymorphonuclear neutrophils. Members of the formyl peptide receptor family recognize chemotactic peptides as well the amyloïd‐β peptide and fragments of the human immunodeficiency virus envelope and may thus be implicated in major pathologies. The peptide WKYMVm‐NH2 probably activates the receptor FPRL1 and its mouse orthologues Fpr‐rs1 and Fpr‐rs2. We examined the stimulation of C57BL6 mouse neutrophils by WKYMVm‐NH2 and the effects of several inhibitors for intracellular signalling pathways (wortmannin, LY 294002, staurosporin, H‐89, U 73122, thapsigargin and SKF 96365). We show here that WKYMVm‐NH2 is a powerful stimulator of primary and secondary granule exocytosis as well as superoxide production. The signalling pathway involves phosphoinositide 3‐kinase, protein kinase C, phospholipase C and store‐operated calcium influx. Studies with peptide antagonists suggest that WKYMVm‐NH2 preferentially activates exocytosis via FPRL1 and not FPR, the major receptor for N‐formylated peptides such as fMLF. However, the signalling pathways activated by WKYMVm‐NH2 in mouse neutrophils are similar to those activated by fMLF in human neutrophils. Thus, the effect and the signalling pathways of the two agonists and their receptors are at least partially overlapping.
Cytokine Responses to Fungal Pathogens in Kupffer Cells are Toll‐like Receptor 4 Independent and Mediated by Tyrosine Kinases
Authors: Øverland G. , Stuestøl J. F. , Dahle M. K. , Myhre A. E. , Netea M. G. , Verweij P. , Yndestad A. , Aukrust P. , Kullberg B. J. , Warris A. , Wang J. E. , Aasen A. O.
Published: August 2005

Disseminated fungal infections are increasing. However, the interactions between the body's largest population of tissue macrophages, the Kupffer cells and the fungal pathogens are scarcely understood. The aim of this study was to examine the involvement of Toll‐like receptor 4 (TLR4) signalling in cytokine production, using primary cultures of rat and murine Kupffer cells exposed to Aspergillus fumigatus and Candida albicans hyphae and conidia. All fungal components induced the release of tumour necrosis factor‐α (TNF‐α), but with delayed kinetics compared with lipopolysaccharide (LPS). Candida albicans was the most potent inducer of TNF‐α protein and mRNA and the only inducer of interleukin‐10 (IL‐10) in rat Kupffer cells. All fungal components induced enhanced mRNA levels of macrophage inhibitory protein‐2 (MIP‐2) in the cells, similar to LPS. Inhibitors of Src tyrosine kinases added to cells prior to stimulation led to attenuation in the release of both TNF‐α (60%, P < 0.05) and IL‐10 (70%, P < 0.05) induced by C. albicans conidia but did not influence the LPS‐mediated cytokine release. Murine Kupffer cells (C57BL/10J) also released TNF‐α as well as the chemokines keratinocyte‐derived chemokine (KC) and MIP‐2 in response to fungal component. Surprisingly, Kupffer cells from TLR4‐deficient C57BL/ScCr mice exhibited significantly enhanced production of KC and MIP‐2 upon stimulation by fungal components compared with control littermates (P < 0.05). Our study demonstrates that Aspergillus and Candida components induce cytokine production in rat Kupffer cells and that the response to C. albicans conidia involves Src tyrosine kinases. The experiments with TLR4‐deficient Kupffer cells suggest that the cytokine response in these cells to fungal component is not mediated by TLR4.
Differentiation of mutans streptococci by intact cell matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Rupf S. , Breitung K. , Schellenberger W. , Merte K. , Kneist S. , Eschrich K.
Published: August 2005

It is difficult to distinguish mutans streptococci on the species level, and even more so on the subspecies level. Intact cell matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) (ICM) was applied to reference strains of five of the species of the mutans group (Streptococcus criceti, Streptococcus downei, Streptococcus mutans, Streptococcus ratti, Streptococcus sobrinus), nonmutans streptococci (Streptococcus oralis, Streptococcus mitis, Streptococcus salivarius, and Streptococcus sanguinis), and 177 mutans streptococci isolated from saliva of 10 children. From the analysis of the reference strains, readily distinguishable ICM mass spectra were obtained for the different species. Based on multivariate statistical analysis, a correct and unambiguous assignment was made of the spectra of 159 isolated mutans streptococci to S. mutans and 16 isolates to S. sobrinus. Two isolates were sorted out and were identified by sequencing of their 16S rRNA genes as Streptococcus anginosus. In addition, ICM indicated a misclassification for some reference strains (AHT, V 100 and E 49) and re‐classified AHT and E 49 as S. ratti and V 100 as S. sobrinus. This was confirmed by 16S rDNA sequencing. Based on a statistical similarity analysis of the spectra of reference strains and a quantitative assessment of the reproducibility of ICM, the isolates identified as either S. mutans or S. sobrinus were phenotyped on the subspecies level. In the population of the clinical isolates, 14 unambiguously different S. mutans and three different S. sobrinus phenotypes were detected. ICM proved to be a powerful tool for a differentiation of mutans streptococci down to the subspecies level.
Influence of genetic background on transformation and expression of Green Fluorescent Protein in Actinobacillus actinomycetemcomitans
Authors: Teughels W. , Sliepen I. , De Keersmaecker S. , Quirynen M. , Lippmann J. , Pauwels M. , Fives‐Taylor P.
Published: August 2005

Background/aims:  The development of an electro‐transformation system and the construction of shuttle plasmids for Actinobacillus actinomycetemcomitans have enhanced the molecular analysis of virulence factors. However, inefficient transformation is frequently encountered. This study investigated the efficiency of electro‐transformation and expression of Green Fluorescent Protein (GFP) in 12 different A. actinomycetemcomitans strains. The influence of the plasmid vector, serotype, and phenotype were the major factors taken into consideration.

Material and methods:  Twelve serotyped A. actinomycetemcomitans strains were independently electro‐transformed with two different Escherichia coli–A. actinomycetemcomitans shuttle plasmids (pVT1303 and pVT1304), both containing an identical ltx‐GFPmut2 gene construct but a different backbone (pDMG4 and pPK1, respectively). The transformation efficiency, transformation frequency, and electro‐transformation survival rate were determined by culture techniques. GFP expression was observed at the colony level by fluorescence microscopy.

Results:  All strains could be transformed with both plasmids. However, major differences were observed for the transformation efficiency, transformation frequency, and electro‐transformation survival rate between strains. The data demonstrated that plasmid vector, serotype, and phenotype are key players for obtaining a successful transformation. An inverted relationship between the electro‐transformation survival rate and tranformation frequency was also observed. GFP expression was also influenced by phenotype, serotype and plasmid vector.

Conclusions:  The serotype of A. actinomycetemcomitans has an important influence on its survival after electro‐transformation and on transformation frequency. The expression of GFP is strain and plasmid vector dependent.