bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of ferritin: a specific role for interferon‐alpha (IFN‐α)? The acute phase response in patients treated with IFN‐α‐2b
Authors: Stam T. C. , Swaak A. J. G. , Kruit W. H. J. , Eggermont A. M. M.
Published: March 2003

Background Adult onset of Still’s disease is characterized by very high serum ferritin levels, in disproportion with other acute phase proteins (APPs). Because interferon‐alpha (IFN‐α) was observed to cause hyperferritinaemia in three healthy people without increase of other APPs, we hypothesized that IFN‐α stimulates specifically the synthesis of ferritin. To test this hypothesis, we studied ferritin and other APP levels in patients treated with IFN‐α.

Patients and methods Fifteen patients treated with IFN‐α‐2b 3–5 times a week, as adjuvant treatment after excision of a high‐risk melanoma, were compared with six patients without adjuvant treatment (controls). Serum levels of C‐reactive protein (CRP) and secretory phospholipase A2 (sPLA2) were measured using ELISA. Levels of ferritin, alpha1‐acid glycoprotein (AAG) and albumin were determined by nephelometry.

Results CRP was decreased significantly after 4 weeks (P < 0·01) in the patients treated with IFN‐α compared with the nontreated patients, after 6 months of treatment it was still decreased although not significantly. Ferritin increased significantly in the IFN‐α‐treated patients: 187% of pretreatment value after 4 weeks and 217% after 6 months (P < 0·01), while ferritin levels decreased in the nontreated patients. AAG increased significantly in IFN‐α‐treated patients (107, 114%) compared with the control‐patients (91, 76%) but differences were less compared with CRP and ferritin. sPLA2 had a variable course, while albumin remained constant within the normal range in both patient groups.

Conclusions IFN‐α induced a significant increase in ferritin, with a significant decrease in CRP, little increase in AAG, varying response of sPLA2 and no change in albumin. This finding suggests a specific role for IFN‐α in the synthesis or secretion of ferritin. This mechanism may also be involved in the marked hyperferritinaemia in adult onset of Still’s disease.
Functional approach to investigate Lp(a) in ischaemic heart and cerebral diseases
Authors: De La Peña‐Díaz A. , Cardoso‐Saldaña G. , Zamora‐González J. , Barinagarrementeria F. , Izaguirre R. , Loyau S. , Anglés‐Cano E.
Published: March 2003

Background Lp(a), a major cardiovascular risk factor, contains a specific apolipoprotein, apo(a), which by virtue of structural homology with plasminogen inhibits the formation of plasmin, the fibrinolytic enzyme. A number of clinical reports support the role of Lp(a) as a cardiovascular or cerebral risk factor, and experimental data suggest that it may contribute to atherothrombosis by inhibiting fibrinolysis.

Design A well‐characterized model of a fibrin surface and an apo(a)‐specific monoclonal antibody were used to develop a functional approach to detect pathogenic Lp(a). The assay is based on the competitive binding of Lp(a) and plasminogen for fibrin, and quantifies fibrin‐bound Lp(a). High Lp(a) binding to fibrin is correlated with decreased plasmin formation. In a transversal case–control study we studied 248 individuals: 105 had a history of ischaemic cardiopathy (IC), 52 had cerebro‐vascular disease (CVD) of thrombotic origin, and 91 were controls.

Results The remarkably high apo(a) fibrin‐binding in CVD (0·268 ± 0·15 nmol L−1) compared with IC (0·155 ± 0·12 nmol L−1) suggests the existence of peculiar and poorly understood differences in pro‐ or anti‐thrombotic mechanisms in either cerebral and/or coronary arteries.

Conclusions Our results demonstrated that Lp(a) fibrin‐binding and small Apo(a) isoforms are associated with athero‐thrombotic disease.
Free fatty acids in obesity and type 2 diabetes: defining their role in the development of insulin resistance and β‐cell dysfunction
Authors: Boden G. , Shulman G. I.
Published: March 2003

Plasma free fatty acids (FFA) play important physiological roles in skeletal muscle, heart, liver and pancreas. However, chronically elevated plasma FFA appear to have pathophysiological consequences. Elevated FFA concentrations are linked with the onset of peripheral and hepatic insulin resistance and, while the precise action in the liver remains unclear, a model to explain the role of raised FFA in the development of skeletal muscle insulin resistance has recently been put forward. Over 30 years ago, Randle proposed that FFA compete with glucose as the major energy substrate in cardiac muscle, leading to decreased glucose oxidation when FFA are elevated. Recent data indicate that high plasma FFA also have a significant role in contributing to insulin resistance. Elevated FFA and intracellular lipid appear to inhibit insulin signalling, leading to a reduction in insulin‐stimulated muscle glucose transport that may be mediated by a decrease in GLUT‐4 translocation. The resulting suppression of muscle glucose transport leads to reduced muscle glycogen synthesis and glycolysis. In the liver, elevated FFA may contribute to hyperglycaemia by antagonizing the effects of insulin on endogenous glucose production. FFA also affect insulin secretion, although the nature of this relationship remains a subject for debate. Finally, evidence is discussed that FFA represent a crucial link between insulin resistance and β‐cell dysfunction and, as such, a reduction in elevated plasma FFA should be an important therapeutic target in obesity and type 2 diabetes.
Redefining the clinical management of type 2 diabetes: matching therapy to pathophysiology
Authors: Gerich J. E.
Published: March 2003

Conventional treatments for type 2 diabetes do not provide adequate glycaemic control to prevent the long‐term progression of the disease. The introduction of increasingly intensive therapeutic regimens in stepwise management strategies aims to maintain glycaemic control in the face of progressive deterioration in β‐cell function. However, such an approach does not entirely address the underlying disease mechanisms. Although much remains unclear about the aetiology of type 2 diabetes, both β‐cell dysfunction and insulin resistance play important roles, and there is a complex, dynamic interaction between these two abnormalities. Growing evidence suggests that treatments that can reverse insulin resistance and improve β‐cell function may be able to slow or prevent the progression of the disease. The clinical management of type 2 diabetes therefore needs to be re‐examined and redefined to reflect new insights into the underlying pathogenetic mechanisms, including consideration of the potential benefits of early, aggressive intervention to counter both β‐cell dysfunction and insulin resistance.
HLA‐B38 and clozapine‐induced agranulocytosis in Israeli Jewish schizophrenic patients
Authors: Valevski A. , Klein T. , Gazit E. , Meged S. , Stein D. , Elizur A. , Narinsky E.R. , Kutzuk D. , Weizman A.
Published: March 2003

To further substantiate reports of an association between the major histocompatibility complex subtypes and clozapine‐induced agranulocytosis, HLA typing was performed in 61 Jewish Israeli schizophrenic patients, in 11 of whom agranulocytosis developed following clozapine treatment and in 50 (controls) of whom it did not. Of the 11 agranulocytosis patients, seven (63%) were of Ashkenazi origin and four (37%) of Sephardi origin. There was no difference in ethnic origin between the agranulocytosis and non‐agranulocytosis groups (χ2 = 2.4, d.f. = 1, P = 0.11), although the agranulocytosis patients had a higher frequency of the HLA B38 antigen (8/11 or 72% vs. 6/50 or 12%; χ2 = 18.7, d.f. = 1, P < 0.001). These results suggest that major histocompatibility complex gene products could be involved in clozapine‐mediated haematological complications.
Routine HLA‐B27 typing by flow cytometry: differentiation of the products of HLA‐B*2702, B*2705 and B*2708
Authors: Coates E. , Darke C.
Published: March 2003

Patient HLA‐B27 typing is widely performed as an aid to the diagnosis of several diseases, particularly ankylosing spondylitis. Typing by flow cytometry, using monoclonal antibodies, has been shown to be a potentially useful alternative to classical serology on account of its speed, simplicity and economy. However, we required a flow cytometry typing procedure that would accurately differentiate HLA‐B27 (Bw4) from B2708 (Bw6) and not be confounded by other HLA‐B7/B27 cross‐reactive group antigens. Accordingly, we evaluated the simultaneous use of two monoclonal antibody preparations, ABC‐m3‐FITC (anti‐B27 + weak B7)/BB7.1‐PE (anti‐B7) and FD705‐FITC (anti‐B27), by testing a highly selected panel of 62 reference lymphocytes containing examples of all HLA‐B7/B27 cross‐reactive group antigens, including: HLA‐B42, B47, B48, B73, B703, B2702, B2705 and B2708. In addition, 268 whole blood samples from routine patient requests for B27‐associated disease typing were tested in parallel with HLA‐B typing using the standard complement‐dependent microlymphocytoxicity test. The detailed specificity of the three monoclonal antibodies was established and the products of HLA‐B*2702, B*2705 and B*2708 were found to be readily differentiated from each other and all other HLA‐B7/B27 cross‐reactive HLA‐B antigens.
Functional characterization and exon 2 – intron 2 – exon 3 gene sequence of HLA‐B*2712 as found in a British family
Authors: Hemmatpour S. K. , Dunn P. P. J. , Evans P. R. , Green A. , Howell W. M.
Published: March 2003

The HLA‐B*27 group of alleles has been extensively studied due to the association of particular B*27 alleles with ankylosing spondylitis (AS). We describe here an HLA‐B*27 allele (B*2712) encoding an antigen that lacks reactivity with B27 monoclonal antibodies (moabs) and alloantisera but reacts with some B40/B60 moabs and alloantisera and expresses the Bw6 public epitope. This allele was discovered by the segregation of an HLA‐B allele undetectable by PCR–SSP within a Caucasian family from the British population referred for routine bone marrow transplant HLA typing and found in the haplotype A*29; B*2712; Cw*1203; DRB1*13; DQB1*0603. Serological typing showed a lack of reactivity with four B27 moabs and four alloantisera but positive reactivity with moabs and alloantisera specific for B40/B60 and Bw6 public epitopes. Subsequent sequencing showed the closest homology was with B*2708 with three mismatches in exon 2 at positions 204, 209 and 210. The intron 2 sequence was identical with other B*27 lineage alleles including a 2 base pair deletion at positions 95 and 96. The relationship between HLA‐B*2712 and reported B60 associations with susceptibility to AS remains to be determined.
Genotyping for human platelet‐specific antigens HPA‐1, ‐2, ‐3, ‐4 and ‐5 in the Slovenian population reveals a slightly increased frequency of HPA‐1b and HPA‐2b as compared to other European populations
Authors: Roz˘man P. , Drabbels J. , Schipper R. F. , Doxiadis Ilias , Stein S. , Claas F. H. J.
Published: March 2003

Typing of human platelet alloantigens (HPA) is necessary in various clinical situations. The purpose of this study was to type a random sample of the Slovenian population for HPA alleles, in order to obtain genetic population data. A total of 152 unrelated Slovenian blood donors were genotyped for HPA‐1, ‐2, ‐3, ‐4 and ‐5 alleles using a simple method that enables simultaneous and complete determination of HPA genotypes. Ten different polymerase chain reactions employing sequence‐specific priming (PCR‐SSP), which worked in identical cycling conditions, were used. The allele frequencies were 0.809 for HPA‐1a, 0.191 for HPA‐1b, 0.891 for HPA‐2a, 0.109 for HPA‐2b, 0.591 for HPA‐3a, 0.407 for HPA‐3b, 0.997 for HPA‐4a, 0.00 for HPA‐4b, 0.934 for HPA‐5a and 0.066 for HPA‐5b. When compared to results of studies of various other Caucasian populations, our population displayed a slightly but not significantly higher proportion of the HPA‐1b and 2b alleles.
Analysis of candidate genes on chromosome 19 in coeliac disease: an association study of the KIR and LILR gene clusters
Authors: Moodie S. J. , Norman P. J. , King A. L. , Fraser J. S. , Curtis D. , Ellis H. J. , Vaughan R. W. , Ciclitira P. J.
Published: March 2003

Coeliac disease is strongly heritable, with more than half of the genetic susceptibility estimated to come from genes outside the HLA region. Several candidate regions have been suggested from genome‐wide linkage studies including chromosome 19q13.4 where linkage has been replicated between populations. The natural killer (NK) cell immunoglobulin‐like receptors (KIRs) and leukocyte immunoglobulin‐like receptor (LILR, also known as ILT and LIR) gene clusters lie within this region in the leukocyte receptor cluster (LRC). KIR molecules are involved in cytotoxic lymphocyte function and expressed by intraepithelial T and NK cells in the duodenum. We studied 132 unrelated UK Caucasian coeliac patients and their parents together with a control group of 171 UK Caucasians. PCR‐SSP for KIR2DL1, KIR2DL2, KIR2DL3, KIR2DL5, LILRA3 (ILT6), LILRA3 deletion and an LILRA3 exon 3 single nucleotide polymorphism (SNP) allowed classification of KIR genotypes into five categories and determination of homozygosity or heterozygosity for the common A and B type KIR haplotypes (as defined in the text) and for the LILRA3 deletion. Case–control analysis found no association of the five KIR genotype categories, the A or B KIR haplotypes, the LILRA3 gene deletion or the LILRA3 exon 3 SNP with coeliac disease. A transmission disequilibrium test also found no association of the A and B KIR haplotypes or the LILRA3 gene deletion with coeliac disease.
Complete characterization of the DQB1 first exon polymorphism
Authors: Pascual M. , López‐Nevot M. A. , Caballero A. , Alonso A. , Zanelli E. , Martín J.
Published: March 2003

Here we report an additional source of variation resulting from genetic polymorphism in HLA‐DQβ1 genes, namely, allelic diversity in the first exon of the HLA‐DQB1 locus, which encodes the leader peptide sequence. Six different variants, including a novel polymorphic site, were detected among the DBQ1 haplotypes.
Modelling simultaneous release, diffusion and nitrification of ammonium in the soil surrounding a granule or nest containing ammonium fertilizer
Authors: WANG  , BEAR  , SHAVIV
Published: March 2003

A model of nitrogen release from ammoniacal fertilizers into soil (e.g. from a controlled release nitrogen (CRN) source) and subsequent nitrification has been developed to assess possibilities for reducing losses of N and environment pollution. Emphasis was placed on the effects of changes in ammonium concentration and pH on nitrification rates, and the interactions of these effects with the rate of release of N from fertilizers. The model considers ammonium release and transport from a spherical source, such as a coated granule of CRN or a nest containing either granules of CRN or an easily dissolved fertilizer (EDF). It is shown that the appearance of nitrate in the soil decreases as the size of the N source increases. This is due to both a decrease in the rate of nitrification, caused by accumulation of ammonium near the source, and a slower relative release (i.e. smaller ratio of N released per unit time to the total mass initially in the source, which is inversely proportional to the radius of a granule or nest). Placement of many CRN granules in a nest is shown to be an effective way to reduce nitrification, particularly in soils having low microbial activities. The less the mobility of ammonium in the soil, the slower will be the nitrification because ammonium accumulates close to the source. A CRN nest leads to more effective reduction of nitrification than an EDF nest and N in it is released more slowly into the soil.
Carbon mineralization, nitrogen immobilization and pH change in soil after adding volatile fatty acids
Authors: SØRENSEN P.
Published: March 2003

Volatile fatty acids (VFAs) accumulate in animal manure when it is stored anaerobically, and they quickly decompose when the manure is applied to soil. In this study the influence of VFAs on the immobilization of N and mineralization of C in soil was investigated by incubating mixtures of acetate, propionate and butyrate in soils containing varying amounts of clay. The oxidation of VFAs (300 μg C g−1 soil) caused a significant increase in pH (0.6–2.2 pH units), with the largest increase in the most coarse‐textured soil. The maximum net immobilization of N resulting from decomposition of the VFAs was 33–77 mg N g−1C and was maximal after 1–5 weeks of decomposition. After this time immobilized N was remineralized, and after 12 weeks the VFAs caused no net immobilization of N in the two most sandy soils. Despite this, the concentration of N in the microbial biomass was still greater in the soil amended with VFAs than in the control. After 12 weeks, the mineralization of C from the decomposition of the VFAs was equivalent to 60–113% of the applied C. It seems that mineralization of native soil C and N was stimulated by adding VFAs, except in the most clayey soil. This stimulation was presumably caused by the increase in the soil's pH as the VFAs oxidized.
A new approach for determining effective soil hydraulic functions
Authors: VOGEL H. J. , ROTH K.
Published: March 2003

We investigated the possibility of inferring effective hydraulic properties of soil from the structure of the pore space. The aim was to identify structural properties, which are essential for water flow, so that physical experiments may be replaced by direct morphological measurements. The pore structure was investigated in three dimensions by serial sections through impregnated samples. The complex geometry of pore space was quantified in terms of two characteristics: pore‐size distribution and pore connectivity. Only pores larger than 0.04 mm were considered. The results were used as input parameters for a pore‐scale network model. The main desorption branch of the soil‐water characteristic and the corresponding hydraulic conductivity function of the network model were calculated by numerical simulation. The simulation results, which are exclusively based on morphological investigations, were compared with independently measured results from a multi‐step outflow experiment. This approach was demonstrated for two centrasting soil materials: the A and B horizons of a silty agricultural soil. The simulations were close to the experimental data, except for the absolute values of the hydraulic conductivity. The pore‐size distribution and pore connectivity govern the shape of hydraulic functions and the applied morphometric methods are suitable for predicting essential characteristics of hydraulic soil properties.
Gas diffusion in a silty‐clay soil: experimental study on an undisturbed soil core and simulation in its three‐dimensional reconstruction
Authors: Cousin I. , Porion P. , Renault P. , Levitz P.
Published: March 2003

Transport of gas in soil depends on the paths available through the porous system. We determined the rate of diffusion of air through a core of silty‐clay soil experimentally. After the experiment, the core was impregnated with resin and sectioned at 100 μm. From the images of the sections, the porous structure was reconstructed in three dimensions with a 100‐μm resolution and gas diffusion was simulated in it. We computed the self‐diffusion to describe gas diffusion. The experiment and simulation were compared using tortuosity, which is the ratio between the self‐diffusion coefficient calculated in air and the coefficient calculated in the reconstructed sample. The results showed that the experimentally measured tortuosity (2.3) and the numerically calculated tortuosity (1.75) were similar. This suggests that the self‐diffusion propagator is useful for simulating self‐diffusion in a numerical three‐dimensional reconstructed sample and that the scale chosen for the reconstruction of the sample (100 μm) was suitable for this particular soil.

Résumé

Les propriétés de transfert en phase gazeuse des sols ont étéétudiées sur un sol limono‐argileux. A l’issue de l’expérience, l’échantillon a été imprégné avec une résine polyester puis sectionné en coupes sériées. A l’aide des images numérisées des coupes, l’échantillon a été reconstruit en trois dimensions. Nous avons ensuite simulé le processus de diffusion gazeuse dans l’échantillon reconstruit à l’aide du propagateur de diffusion. Expérience et simulation ont été comparées à l’aide de la tortuosité, rapport entre le coefficient de diffusion gazeuse dans l’air et celui dans le sol. Les résultats montrent que la tortuosité mesurée expérimentalement (2,3) et la tortuosité calculée numériquement (1,75) sont proches. Ceci prouve que l’utilisation du propagateur de diffusion est justifiée pour la simulation du processus de self‐diffusion dans un échantillon tridimensionnel reconstruit et que l’échelle choisie pour la reconstruction (100 μm) s’avère pertinente pour l’étude de la diffusion gazeuse dans ce sol.
Vertical distribution of low molecular weight aliphatic carboxylic acids in some forest soils of Japan
Authors: Tani M. , Higashi T.
Published: March 2003

Low molecular weight organic acids are widespread and reactive in soils, but their distribution among mineral horizons is uncertain. We investigated the distribution of low molecular weight aliphatic carboxylic acids (LACAs) in three Japanese forest soils, two Acid Brown Forest soils and one Podzolic soil. The total LACAs ranged from 207.3 to 411.8 μmol kg–1 and were abundant in the lower horizons as well as in the surface horizons of these soils. The illuvial horizons of the Podzolic soil were rich in adsorbed oxalic acid and citric acid. Total LACAs were similar in the two subtypes of Brown Forest soils derived from different parent materials but formed under similar vegetation and climate, and were larger than that in the Podzolic soil. Among the volatile LACAs, formic acid and acetic acid dominated the moist horizons containing much organic material, whereas the non‐volatile LACAs, the most abundant being oxalic acid and citric acid, increased in the subsurface horizons. The distribution of water‐soluble LACAs in the Brown Forest soil profiles was closely correlated with soil acidity.
Simulation of the effect of citrate exudation from roots on the plant availability of phosphate adsorbed on goethite
Authors: Geelhoed J. S. , Van Riemsdijk W. H. , Findenegg G. R.
Published: March 2003

Rhizosphere processes strongly influence the availability of phosphorus (P) to plants. Organic ligands that are exuded from the root surface mobilize phosphorus by dissolution of P minerals or by desorption of adsorbed phosphate. We developed a mechanistic model to study the mobilization of phosphate sorbed on goethite by the exudation of citrate and consequent uptake of phosphate by the root. The use of a model allows the effects of the organic anion and pH on P desorption to be separated. The model is also used to predict concentration profiles developing around the root for phosphate, citrate (with or without accounting for degradation) and pH, providing insight into the processes that occur in the rhizosphere. Results of model calculations show that with larger rates of citrate exudation, greater P availability is predicted. Exudation at a rate of 0.5 μmol citrate m–1 root day–1, which is in the range found for P‐deficient plants, increased P availability almost 2‐fold at fairly large phosphate loading of goethite (1.9 μmol m–2) and almost 30‐fold at small phosphate loading (1.3 μmol m–2). Competitive adsorption causes a much greater relative increase in the phosphate concentration in solution at small than at large phosphate loading, which explains this result. Simultaneous acidification of the rhizosphere results in a smaller P mobilization than at a fixed pH of 5, as a result of the pH dependence of phosphate adsorption in the presence of citrate. Sorption of citrate increases its persistence against microbial decay, and hence has a positive effect on the mobilization of adsorbed phosphate.
A numerical experiment on pore size, pore connectivity, water retention, permeability, and solute transport using network models
Authors: Vogel H. J.
Published: March 2003

Network models are idealized geometrical representations of porous media. They allow the simulation of effective hydraulic properties and of solute transport for well‐defined porous structures. In this paper, the relation between pore structure and effective properties is studied using a network model which can be adjusted to predefined pore‐size distributions and pore topologies. I show that pore topology can be adjusted such that quite different pore‐size distributions lead to essentially identical water retention curves. This puts into question the common interpretation of the retention curve as being indicative of the pore‐size distribution. However, I also found that both the hydraulic conductivity and the dispersion of a solute depend on the water retention curve and not on the particular combination of pore‐size distribution and topology which make it up. This corroborates the widely used approach of inferring relative permeabilities from water retention data.
The effect of iron concentration, hindered settling, saturating cation and aggregate density of clays on the size distribution determined by gravitation X‐ray sedimentometry
Authors: Watts C. W. , Whalley W. R. , Bird N. R. A. , Ashman M. R.
Published: March 2003

X‐ray sedimentation is potentially attractive for estimating the particle‐size distribution of soil, but has been thought to overestimate clay fractions because of the iron they contain. We have examined X‐ray sedimentation for estimating the particle‐size distribution of fully dispersed and of aggregated clay. We obtained good agreement between the pipette and X‐ray sedimentation methods using two different kaolinite samples with a small iron concentration. We also studied montmorillonite saturated with Li, Na, K, Mg or Ca to investigate possible effects of hindered settling. For the Ca montmorillonite, we obtained good agreement between X‐ray sedimentation and the pipette method at concentrations up to 40 g l−1. We also found that X‐ray sedimentation could be used at concentrations less than those recommended by the manufacturer. Hindered settling was observed at concentrations > 20 g l−1 for Li‐ and Na‐saturated montmorillonite. Our data suggest that conducting experiments at different mass concentrations is a sensitive test to detect such problems. Finally we used a fractal model to investigate the possible errors that might result from the size dependence of aggregate density and show that the error caused by assuming a single value for particle density of solids is small.
Reactions of zinc with iron‐oxide coated calcite surfaces at alkaline pH
Authors: Uygur V. , Rimmer D. L.
Published: March 2003

Both iron oxides and carbonate minerals, such as calcite, can sorb zinc (Zn), and therefore are important in controlling the solution concentration and availability of Zn to plants growing in calcareous soil. When present together, interactions between these components affect their sorption behaviour. We investigated changes in the reactions of Zn with calcite at alkaline pH, as the calcite surface was progressively coated by iron oxide. Coated calcite surfaces were prepared that had from 0.05 to 1.45% iron oxide. The initial concentration of Zn and the amount of iron oxide on the calcite were the most critical factors affecting adsorption, precipitation of solid phases, and the desorbability of sorbed Zn. For pure calcite at small initial Zn concentrations (< 2.5 × 10−5 m) adsorption was dominant; with increasing concentration, precipitation of hydrozincite (ZHC) became more important. With increasing amounts of iron oxide the amount of Zn adsorbed increased, the desorbability of the Zn decreased, and precipitation became progressively less evident, and at 1.45% iron oxide content there was no evidence of any precipitation of ZHC. The calculated maximum adsorption attributable to the iron oxide coating was inversely proportional to the thickness of the oxides on the calcite, and greatly exceeded that of iron oxide as a separate phase. The common occurrence of iron‐coated carbonates in calcareous soils and their capacity to adsorb Zn contributes to the problems of Zn deficiency, for which these soils are noted.
Aluminium solubility mechanisms in moderately acid Bs horizons of podzolized soils
Authors: Gustafsson J. P. , Berggren D. , Simonsson M. , Zysset M. , Mulder J.
Published: March 2003

The processes controlling the retention and release of aluminium in acid forest soils are still subject to controversy, and therefore a universal hypothesis as to what mechanisms are operating has not been firmly established. By studying the Bs horizons of Swedish and Swiss podzolized soils, and by analysing data in the literature, we have found that aluminium hydroxide, and in some cases also poorly ordered imogolite, may control Al solubility in moderately acid (pH > 4.2–4.3) Bs horizons. The strongest evidence in support of the presence of a quickly reacting Al(OH)3 pool came from the temperature dependence of Al solubility in a Bs horizon, which was consistent with the reaction enthalpy of an Al(OH)3 phase such as gibbsite, and from the observation that the ion activity product for Al(OH)3 was the same regardless of whether equilibrium was reached from over‐ or undersaturation. The pool of Al(OH)3 is commonly small and may be completely dissolved after large additions of acid. This may be explained by the continuing redissolution of reactive Al(OH)3 to form less soluble imogolite‐type phases. By using the same methods it was found that soil suspensions did not reach equilibrium with poorly ordered imogolite even after 17 days. Thus, imogolite probably does not control Al solubility in the short term in many soils despite the common occurrence of this mineral. This is due to the relatively slow kinetics of imogolite formation and dissolution, especially at low temperatures and at small solution H4SiO4 concentrations.
Effect of termites on clay minerals in tropical soils: fungus‐growing termites as weathering agents
Authors: Jouquet P. , Mamou L. , Lepage M. , Velde B.
Published: March 2003

Termites of the subfamily Macrotermitinae play an important role in tropical ecosystems: they modify the soil's physical properties and thereby make food available for other organisms. Clay is important in the architecture of Macrotermitinae termite nests, and it has been postulated that termites could modify the mineralogical properties of some clays. We have tested this hypothesis of clay transformation by termites in the laboratory under controlled conditions, using Odontotermes nr. pauperans termite species, one of the main fungus‐growing species at Lamto Research Station (Côte d'Ivoire). Soil handled by termites in nest building was saturated with SrCl2, glycol or KCl and afterwards heated at 250°C for X‐ray diffraction analyses. Termite handling led to an increase in the expandable layers of the component clay minerals. Heating and saturation by potassium of modified clays did not close the newly formed expandable clay layers. However, differences occurred between parts of the constructions built by termites, and the clays can be ranked according to their degree of alteration in the following order: unhandled soils < galleries < chamber walls. Consequently, termites can be seen as weathering agents of clay minerals, as previously shown for micro‐organisms and plants.
Framework for the development and management of inland fisheries
Authors: WELCOMME R. L.
Published: March 2003

Abstract A framework is described which proposes a sequential series of questions to guide the fisheries manager or student of fisheries through the process of planning and managing an inland fishery. It proceeds from such general issues as the place of inland fisheries in national and regional sector plans to prescriptions for the application of specific techniques for the assessment of the fishery and the implementation of management procedures.
Otter guards in river fyke‐net fisheries: effects on catches of eels and salmonids
Authors: Koed A. , Dieperink C.
Published: March 2003

The effects of otter guards on the fishing efficiency of eel fyke‐nets were investigated in two Danish rivers. The otter guards were made of 75‐mm mesh netting and were placed across the fyke entrance. The fishing efficiency was measured as catch‐per‐unit effort and hauling time. Guard nets were mounted in half the fyke‐nets, while the other half served as controls. After every haul, the fyke‐nets with guard nets were returned to controls and vice versa. For legal‐sized eels and salmonids, the guard‐net significantly (P < 0.05) reduced the catches, causing a 30% reduction of the eel catch and a 53–55% reduction of the salmonid catch. The use of otter guards significantly increased the hauling time. The average time used for hauling a guarded fyke‐net was increased by 15–25% for both upstream‐ and downstream‐oriented fyke‐nets, respectively. Blockages caused by water‐borne debris appear to be the main cause of problems.Anguilla anguilla, by‐catch, eel, fyke‐net, otter guards, salmonid.
The use of brushwood bundles as fish spawning media
Authors: Nash K. T. , Hendry K. , Cragg‐Hine D.
Published: March 2003

Salford Quays is a redeveloped freshwater dockland, which initially constituted part of the grossly polluted Manchester Docks, Manchester, UK. Such water bodies are characterized by a lack of suitable spawning sites and littoral refuges, and this will act to reduce fish recruitment. To redress this, a variety of artificial spawning substrates were introduced to these waters. Spawning structures were made from bundles of different types of thin brushwood suspended from the dock walls. Roach, Rutilus rutilus (L.), spawned on bundles of willow, Salix alba (L.), and spruce, Pilea abies (L.), branches, whilst perch, Perca fluviatilis L., spawned on bundles of willow, sycamore, Acer pseudoplatanus (L.), spruce and plastic netting. Unused bundles were made up of lime, Tilia platyphyloss (Scop.), pear willow, Pyrus salicitolia (Pall.), and laurel, Laurus nobilis (L.). Perch spawning began around 20 May and showed a preference for open structures (between one and three ribbons per bundle). Roach spawning began about 10 days after perch and showed a preference for dense bundles of spruce (geometric mean egg density 1.5 cm− 2 spruce). The use of such structures in fisheries management is discussed.
How juvenile Atlantic salmon,Salmo salarL., respond to falling water levels: experiments in an artificial stream
Authors: Huntingford F. A. , Aird D. , Joiner P. , Thorpe K. E. , Braithwaite V. A. , Armstrong J. D.
Published: March 2003

The responses of juvenile Atlantic salmon,Salmo salarL., to an experimentally imposed drop in water level were studied in an artificial stream. In a pilot experiment, 20% of fish which had a feeding station in an area of riffle remained there throughout the period of low water levels. The remaining riffle‐dwelling fish moved into areas of deeper water, although not necessarily to the pool nearest their feeding station. Out of the fish which left the area, 89% moved in an upstream direction and 11% moved downstream. In a second experiment, which was designed to look in more detail at this response to de‐watering, 95% of riffle‐dwelling fish left when the water level dropped and moved into a pool, mostly within the 4‐h period after water levels started to fall. Seventy‐four per cent of fish which left moved upstream and the remainder moved downstream. There was a strong tendency to leave in an upstream direction as shallow areas began to dry out, and this tendency persisted irrespective of variability in fish size, prior social experience and the size of the home range prior to de‐watering. It is suggested that the prior opportunity to explore alternative habitat may be an important determinant of response of riffle‐dwelling salmon to a sudden drop in water level.
Timing of migration and changes in age structure of Atlantic salmon, Salmo salar L., in the River Frome, a Dorset chalk stream, over a 24‐year period
Authors: Welton J. S. , Beaumont W. R. C. , Ladle M.
Published: March 2003

During the last 24 years, the number of Atlantic salmon, Salmo salar L., migrating up the River Frome has varied between < 1000 and > 4000 fish per annum. Most parr become smolts at age 1+ and there are three main sea ages of salmon returning to the river. Each sea age shows a bimodal pattern of migration in the river. Primary migration times for 3‐sea‐winter (3SW) fish are spring and autumn, with 2SW fish and grilse (1SW) peaking in summer and autumn. Some 28.4% of 3SW and 6.9% of 2SW fish are previous spawners. Multi‐sea‐winter fish historically passed over the counter in all months of the year, but recently, their numbers have declined, as have total numbers of fish of all ages. There has been a fundamental change in the age structure of the population, with grilse increasing in proportion over the study period. Photographs of fish, taken for validation of the counter, showed a significant decrease in mean length of grilse, but an increase in mean length for 2SW and 3SW fish. Rod catch data support these findings.
Hydropower and instream flow requirements for fish in Sweden
Authors: Svensson B. S.
Published: March 2003

SwedPower AB, Stockholm, SwedenStandardized methods for determining instream flow needs in connection with hydropower development have still not been established in Sweden. However, claims related to conflicting uses of running waters have long engaged the Water Right Courts. Historically, the floating of timber has constituted a strong reason for regulating rivers. Later, the creation of large reservoirs and the subsequent alteration of the natural river flow have mainly been related to the generation of hydroelectricity. In recent decades, the expectations of stakeholders have also been directed at recreational fisheries and the maintenance of biodiversity. Dry channels below diversion points are no longer considered acceptable. Swedish legislation allows for a regular review and reissue of permits to regulate rivers and operate hydroelectric power plants. However, it is only possible to enforce changes which are economically reasonable. The maximum loss of electricity which must be endured by a producer without reciprocal demands of compensation amounts to 5%. Presently, fishing may be regarded as the second most important interest in terms of the use of river resources. Accumulated knowledge of fish ecology makes it possible to use models for the management of fish populations. However, decisions regarding minimum releases of water are usually still based on the natural hydrograph rather than on documented relationships between fish yield and the characteristics of the watercourse. Over the past 7 years, Vattenfall, the largest producer of hydroelectricity in Sweden, has carried out research and development to test, improve and introduce instream flow methods for the management of regulated rivers. Experiences regarding biotope adjustments as an alternative to increased releases of water are presented, and the economic and biodiversity aspects are discussed.
Potential impact of groundwater augmentation of river flows on fisheries: a case study from the River Ouse, Yorkshire, UK
Authors: Cowx I. G.
Published: March 2003

Many lowland rivers in the UK are under increasing pressure from abstraction of water for potable supply or irrigation. Many schemes, both existing and proposed, attempt to mitigate the loss of flow by augmentation from upstream reservoirs or pumping of groundwater into adjacent rivers. The impact of flow regulation by reservoirs is well documented, but little attention has focused on the effect of groundwater augmentation on the biota, particularly fisheries, in the receiving river. The present paper examines the potential effects of pumping groundwater into minor tributaries of the Yorkshire Ouse in England on the cyprinid fisheries downstream of the discharge points and in the main river channel. Concerns were raised with respect to poor water quality and reduced water temperature. In particular, it was predicted that small reductions in river water temperature brought about by discharge of cold (≤ 10 °C) groundwater could have serious detrimental effects on cyprinid fish recruitment and juvenile growth in the receiving river, leading to a decline in stocks.
The commercial fisheries of the lower Amazon: an economic analysis
Authors: Almeida O. T. , McGrath D. G. , Ruffino M. L.
Published: March 2003

This study characterizes the fishermen and the commercial fishing fleet of the lower Amazon, based on data collected from 5446 boats operating out of the city of Santarém in 1997. An economic analysis of the activities of these boats was based on 50 interviews with boat operators. Larger and smaller boats use essentially the same technology, but there are significant differences in fishing strategies. Smaller boats supply local markets and their catch consists of a large variety of fish species. Larger boats tend to specialize in a small number of catfish species, and supply fish processing plants. Smaller boats are less efficient in terms of catch per unit effort (CPUE) (kg fisherman–1 day–1), but are more efficient economically, earning more for each unit of capital invested than larger boats. Most boats operating from Santarém have a storage capacity of <4 t. Boats in this size (0<4 t) account for 87% of the total fleet direct employment, and 73% of total income. Thus despite the lack of attention from regional policy makers, these smaller boats are an important source of food, income and employment in the lower Amazon region.
Impacts of in‐stream acclimatization in post‐stocking behaviour of European grayling in a Swedish stream
Authors: THORFVE STEFAN
Published: March 2003

Abstract The post‐stocking behaviour of hatchery‐reared juvenile European grayling, Thymallus thymallus (L.), with in‐stream acclimatization in a pool for 4, 8, and 12 days before release was compared with fish released directly into a 370‐m long seminatural stream during 1995 and 1996. The behaviour of these groups was compared with fish acclimatized for 16 h in a holding pen (0.7 m3) in a more fast‐flowing part of the stream. All fish were released in the experimental stream at the same time. Initially groups of 30 individuals were compared, but this was reduced because of the mortality during acclimatization. Temporal and spatial distribution, feed intake in relation to sex and size of fish were followed for 7 days after release. Between 33 and 59% of all groups of fish released into the pool left the experimental area and were recaptured in a trap at the downstream end of the experimental stream. The acclimatization period had no significant influence on the percentage of fish moving downstream. Significantly more grayling left the stream from the holding pen (76.7%) than fish released in the pool (47.2%). Of the recaptured fish, 77% had been feeding. Fish recaptured within a week had lost more than 10% of their initial weight measured at the hatchery. Fish recaptured more than 2 weeks after release had lost a significantly smaller percentage of their initial weight compared with fish recaptured in the first 2 weeks. No differences were found in spatial distribution or feeding activity between sexes.
The Irish sea trout enhancement programme: a review of the broodstock and ova production programmes
Authors: POOLE W. R. , BYRNE C. J. , DILLANE M. G. , WHELAN K. F. , GARGAN P. G.
Published: March 2003

The Irish sea trout, Salmo trutta L., broodstock programme was instigated in response to the collapse of sea trout stocks in the west coast of Ireland in 1989 and 1990. Wild sea trout kelts and post‐smolts were successfully reconditioned and used as broodstock to produce eyed ova for distribution to affected fisheries. From 1991 to 1999, a total of 8.2 million green ova from four separate stocks were produced. The number of females stripped increased from 34 in 1991 to a peak of 1435 in 1997. Green ova survival to the eyed ova stage ranged from 65 to 96%. The eyed ova produced were distributed to 23 affected fisheries along the west coast. The average cost per eyed ova decreased from €2.02 at the start of the programme to €0.04 at the end. The growth rates recorded for broodstock held in captivity were comparable with those recorded for wild sea trout. Relationships between fish size, egg size and number of eggs produced were examined for each stock and for each stock in each year. Significant positive relationships were found between fish size and egg number and fish size and egg size, with the exception of the first year in which fish were stripped, when a negative correlation between fish size and egg size was found.
Comparison of mortality of wild and released reared 0‐group turbot, Scophthalmus maximus, on an exposed beach (Ría de Vigo, NW Spain) and a study of the population dynamics and ecology of the natural population
Authors: Iglesias J. , Ojea G. , Otero J. J. , Fuentes L. , Ellis T.
Published: March 2003

Abstract
 Marked reared turbot,
Scophthalmus maximus (L.) (594) were released onto an exposed beach nursery ground together with marked wild fish (438) of approximately the same size (4–6 cm TL) and were sampled at intervals for 38 days. A consistent ratio of marked wild: unmarked wild indicated that marking did not increase mortality. The wild 0‐group turbot population size was estimated at 1540 at the time of release, indicating that hatchery‐reared individuals could theoretically make a significant contribution to the local population size. However, the absolute and relative catches of the marked, reared fish were lower than those of the marked wild fish, and no reared fish were caught after 23 days. The higher mortality rate was attributed to both a smaller size and their hatchery‐reared origin. The population dynamics of the 1994–1995 year‐classes of wild turbot were also studied. Recruitment of post‐larvae (3 cm) to the beach started in March and continued until October. Population size peaked over the August–October period. Juvenile turbot remained on the nursery beach until June of the following year when they presumably emigrated to deeper water. During this 15‐month period their length increased from 3 to 12–15 cm.
Uncertainty about estimating total returns of Atlantic salmon, Salmo salar to the Gander River, Newfoundland, Canada, evaluated using a fish counting fence
Authors: O'Connell M. F.
Published: March 2003

Abstract
 For a number of rivers in Newfoundland, Atlantic salmon,
Salmo salar L., is managed in relation to river‐specific conservation spawning requirements. One such river is the Gander River, where between 1989 and 1999, the escapement of Atlantic salmon, a major factor in assessing the status of stock, was determined using a fish counting fence. In 2000, the counting fence was discontinued and alternative means of calculating total returns were explored. Regression and simulation methods, using relationships between total returns and salmon counts at an upstream tributary during 1989–99, formed the basis for estimates of returns for 2000, and the uncertainty around estimates. The accuracy of methods is evaluated by retrospective comparisons with actual total returns between 1989 and 1999. Estimates of total returns deviated from the actual by as much as 50–60%, depending on the method. Management implications of the approach are discussed.