bluuebunny/crossref_metadata_2025 huggingface dataset:
Variability of Nt‐proANP and C‐ANP
Authors: McDowell G. , Patterson C. , Maguire S. , Shaw C. , Nicholls D. P. , Hall C.
Published: March 2003

Background Natriuretic peptides are frequently measured in patients with chronic cardiac failure (CCF). We set out to compare the variability of atrial natriuretic peptide (C‐ANP) and its precursor N‐terminal pro‐ANP (Nt‐proANP) to decide which would be more suitable for routine use.

Methods Ten males with compensated CCF (age range 62–76 years) were studied, with matched controls. Blood was withdrawn every 2 min for 90 min from a forearm vein, and plasma C‐ANP and Nt‐proANP were measured by radioimmunoassay.

Results Levels were elevated in the patient group [C‐ANP: median 268 (range 171–423) vs. 40 (28–56) ng L−1, P < 0·0002 Mann–Whitney U‐test; Nt‐proANP: 1955 (562–4451) vs. 621 (409–961) pmol L−1, P < 0·003]. A similar number of ‘peaks’ was observed in both groups with both peptides, about one every 10 min, and their relative height was similar in both groups. Variability was greater for C‐ANP than for Nt‐proANP in both patients [coefficient of variation of means 51 (range 36–70) vs. 3·6 (2·1–6·2)%, P < 0·01; sign test] and controls [65 (49–83) vs. 8·9 (4·7–13·5)%, P < 0·01].

Conclusion Nt‐proANP is less variable than C‐ANP and hence more suited for diagnostic or prognostic use.
Differential regulation of atrial and brain natriuretic peptides and its implications for the management of left ventricular volume overload
Authors: Dzimiri N. , Moorji A. , Afrane B. , Al‐Halees Z.
Published: March 2003

Background In this study, we investigated the possibility that the atrial and brain natriuretic peptide expression in left ventricular volume overload (VOL) is transcriptionally regulated. We further evaluated the diagnostic and/or prognostic potential of this expression for the management of patients with this disorder.

Design We compared the myocardial mRNA expression and plasma levels of the two peptides in VOL patients using donor hearts and in healthy blood donors as controls.

Results The atrial natriuretic peptide (ANP) mRNA was elevated by 38% (P < 0·03) in the right atrium and by 53% (P < 0·003) in the left atrium, but was unchanged in the ventricular chambers of the patient group (n = 19) compared with controls (n = 8). Plasma ANP concentration was elevated by 62% (P < 0·001) compared with blood donor controls (n = 79). It increased slightly (by 36%) 2 h following surgery, and remained at 64% higher (P < 0·03 vs. presurgery) for the 5 days following surgery. The brain natriuretic peptide (BNP) mRNA was elevated by approximately one‐fold in both the left ventricle (P < 0·02) and right atrium (P < 0·05), by 94% (P < 0·02) in the right ventricle and by 89% (P < 0·05) in the left atrium. Its plasma level in the patients was 3·4‐fold (P < 0·00003) higher than in control subjects. It increased significantly by 1·2‐fold (P < 0·01) 2 h following surgery, but dropped significantly (P < 0·05 vs. 2 h post surgery) to presurgical levels 5 days following surgery.

Conclusion The results show chamber‐specific elevation in both atrial and brain natriuretic peptide expression and differences in their circulating levels in VOL, suggesting that BNP is a potential prognostic indicator in the postsurgical management of these patients.
Prediction of body weight changes caused by changes in energy balance
Authors: Christiansen E. , Garby L.
Published: March 2003

Background Experimental difficulties have so far restricted knowledge of the effects of energy imbalance on change in body weight. Direct measurement requires that the subjects are kept under dietary supervision for several months while the activity is being measured.

Materials and methods The effects of energy balance can be calculated using a combination of fundamental principles and directly measurable data: the law of energy conservation (increase in combustible energy equals the difference between energy intake and energy expenditure); data on energy expenditure of fat and lean tissues; and data on the composition of added/removed tissue during weight change.

Results and Conclusions We obtained an explicit differential equation describing the development of body weight over time, with energy intake and energy expenditure as control variables. Using this model it is possible to isolate and analyse the measured effects of parameters not included in the model, such as age or ‘adaptivity’ of the body.
Inhaled nitric oxide: more than a selective pulmonary vasodilator
Authors: Gianetti J. , Bevilacqua S. , De Caterina R.
Published: March 2003

Because of its high diffusing capacity through the alveolar–blood barrier and its high selectivity for the pulmonary vasculature, inhaled nitric oxide (NO) has been recently shown to be a viable and efficient approach to restore pulmonary NO deficiency.

The most relevant applications of inhaled NO are in infants with primary pulmonary hypertension or hypoxia. In these patients, inhaled NO improves gas exchange and ventilation‐perfusion matching, reduces the length of hospitalization and is without severe detrimental effects. The use of inhaled NO has also been extended to adults with pulmonary hypertension and the acute respiratory distress syndrome. In addition, recent clinical evidence supported by data from animal models, shows beneficial extra‐pulmonary effects of inhaled NO, including protection against myocardial ischaemia‐reperfusion injury.
High oxidized LDL and elevated plasma homocysteine contribute to the early reduction of myocardial flow reserve in healthy adults
Authors: Laaksonen R. , Janatuinen T. , Vesalainen R. , Lehtimäki T. , Elovaara I. , Jaakkola O. , Jokela H. , Laakso J. , Nuutila P. , Punnonen K. , Raitakari O. , Saikku P. , Salminen K. , Knuuti J.
Published: March 2003

Background Impairment of coronary blood flow reserve has been shown to be an early manifestation of atherosclerosis and coronary artery disease (CAD). We studied more closely the contribution of various risk factors on early deterioration of coronary function.

Materials and methods Fifty‐one young, apparently healthy adults, with normal or mildly elevated serum cholesterol levels but without other major risk factors for CAD, such as diabetes or hypertension, underwent positron emission tomography (PET) studies. Coronary flow reserve (CFR) was measured using O15‐water. In addition to the classical risk factors, the role of several new risk indicators, such as low‐density lipoprotein (LDL) oxidation, infection (Chlamydia pneumoniae antibodies), and inflammation parameters (adhesion molecules, ICAM, VCAM, selectin, and C‐reactive protein), homocysteine and body iron stores were investigated.

Results Elevated lipid and lipoprotein levels were not associated with reduced coronary reactivity. However, high autoantibody titers against oxidized LDL (oxLDL) were associated with 21% lower CFR than low oxLDL (P < 0·05). Furthermore, high homocysteine levels predicted low CFR (P < 0·05). The other measured parameters, Chlamydia pneumoniae antibody levels, C‐reactive protein and adhesion molecule concentrations did not associate with myocardial blood flow. In a stepwise regression model, oxLDL (P = 0·03), homocysteine (P = 0·04) and triglycerides (P = 0·018) were significant predictors of CFR.

Conclusions The present study suggests an important role for oxidized LDL and plasma homocysteine on early impairment of coronary reactivity in young adults.
Pneumococcal immune adherence to human erythrocytes
Authors: Hament J.‐M. , Van Dijk H. , Fleer A. , Aerts P. C. , Schoenmakers M. , De Snoo M. W. , Th. Dekker B. H. A. , Kimpen J. L. L. , Wolfs T. F. W.
Published: March 2003

Background Human red blood cells bind various C3b‐coated microorganisms via their C3b/CR1 receptor, a phenomenon referred to as immune adherence. The aim of the present study was to measure pneumococcal adherence to human red blood cells by flow cytometry and to study kinetic aspects of this binding.

Material and methods We quantified pneumococcal adherence to human erythrocytes by FACS analysis and tested the involvement of antibodies and complement activation in this process.

Results Pneumococci are able to bind to human red blood cells in the presence of human serum. Coating with C3b/C4b appeared obligatory for pneumococcal adherence to red blood cells. The ligand on erythrocytes was confirmed to be complement receptor 1. Kinetic studies showed that innate (mannose‐binding lectin) and specific immune factors (IgG antibodies) contributed to the binding of C3b‐coated pneumococci to human erythrocytes. After initial binding, serum‐derived factor I was found to induce bacterial detachment from the erythrocyte.

Conclusions Pneumococci are able to adhere to red blood cells. Both the classical and lectin complement pathways are important for optimal C3b‐coating of pneumococci for immune adherence. Bound pneumococci are detached from red blood cells by factor I. These findings are in line with the hypothesis of immune adherence in which human erythrocytes are able to bind pneumococci and target the bacteria to the reticulo‐endothelial system in the spleen.
Iron, hepatic stellate cells and fibrosis in chronic hepatitis C
Authors: Rigamonti C. , Andorno S. , Maduli E. , Morelli S. , Pittau S. , Nicosia G. , Boldorini R. , Sartori M.
Published: March 2003

Background/aims  In patients with chronic hepatitis C, hepatic iron concentration correlates with liver fibrosis. However, it is not clear whether this correlation merely reflects the presence of more active disease, or iron exacerbates chronic hepatitis C virus (HCV)‐induced damage through activation of hepatic stellate cells and regeneration of hepatocytes.

Materials and methods  We studied 72 HCV‐positive patients, staged according to the Ishak’s score system. We measured hepatic iron concentration with spectrophotometry and evaluated the number of hepatic stellate cells (using monoclonal antibody against alpha smooth muscle actin) and proliferating hepatocytes (using monoclonal antibody against Ki67). Iron and ferritin serum levels were also determined.

Results  Hepatic iron concentration correlated statistically with ferritin serum level (r = 0·59, P < 0·001), with grading (r = 0·47, P < 0·001) and staging (r = 0·51, P < 0·001) scores for chronic hepatitis in the whole group of patients. Hepatic iron concentration correlated positively with stellate cell number (r = 0·55, P = 0·004) and Ki67‐positive hepatocyte number (r = 0·36, P = 0·08) in patients with chronic hepatitis C and low grading score (< 3).

Conclusions

 In patients with chronic hepatitis C and low grading score, hepatic iron could play a role in the activation of hepatic stellate cells and in the progression of fibrosis.
Iron and immunity: a double‐edged sword
Authors: Weiss G.
Published: March 2003

Iron is a crucial element for many central metabolic pathways of the body. Lack of iron leads to growth arrest and anaemia while increased accumulation of this metal, as it occurs in highly frequent inherited diseases such as hereditary haemochromatosis and thalassaemia, is associated with toxic radical formation and progressive tissue damage. As shown by several groups, iron also modulates immune effector mechanisms, such as cytokine activities (IFN‐γ effector pathways towards macrophages), nitric oxide (NO) formation or immune cell proliferation, and thus host immune surveillance. Therefore, gaining control over iron homeostasis is one of the central battlefields in deciding the fate of an infection with intracellular pathogens or a malignant disease. Thus, the reticulo‐endothelial system has evoked sophisticated strategies to control iron metabolism in general and especially the handling of the metal within immune cells.
Impact of genetic defects on coronary atherosclerosis in patients suspected of having familial hypercholesterolaemia
Authors: Descamps O. S. , Gilbeau J.‐P. , Luwaert R. , Heller F. R.
Published: March 2003

Background In the present study we assessed whether the presence of genetic mutations typical of familial hypercholesterolaemia (FH) was associated with greater atherosclerosis in the coronary vessels in patients with severe hypercholesterolaemia and a family history of early cardiovascular disease.

Materials and methods Two hundred and thirty‐five patients selected for having severe hypercholesterolaemia and a family history of cardiovascular disease were classified as FH (57 men and 38 women) or non‐FH (84 men and 56 women) according to a genetic analysis of the LDL‐R or ApoB genes. Coronary atherosclerosis was evaluated by performing a thoracic CT scan and exercise stress testing.

Results Familial hypercholesterolaemia individuals had a significantly higher prevalence of coronary calcification than the non‐FH patients from among both the men (OR = 3·90; 95% CI 1·86–8·19; P < 0·001) and the women (OR = 2·34; 95% CI 1·01–5·48; P = 0·05). In exercise stress testing, ECG abnormalities suggestive of cardiac ischaemia were found with a higher prevalence in the FH patients than the non‐FH patients from among both the men (OR 6·15; 95% CI 2·16–17·5; P < 0·001) and the women (OR 4·76; 95% CI 0·91–24·6; P = 0·06). All differences were statistically significant after adjusting for age and cholesterol and for most classical risk factors that differed between the FH and non‐FH groups.

Conclusion Among patients with severe hypercholesterolaemia and a family history of early cardiovascular disease, the presence of a genetically ascertained FH is associated with a higher prevalence of coronary artery calcifications and a positive exercise stress test. These results suggest that despite a similar phenotype, patients carrying mutations suggestive of FH may have a greater cardiovascular risk than patients without these mutations.
Dose‐effect relations of loop‐ and thiazide‐diuretics on calcium homeostasis: a randomized, double‐blinded Latin‐square multiple cross‐over study in postmenopausal osteopenic women
Authors: Rejnmark L. , Vestergaard P. , Pedersen A. R. , Heickendorff L. , Andreasen F. , Mosekilde L.
Published: March 2003

Background Thiazide diuretics (TDs) reduce whereas loop diuretics (LDs) increase urinary calcium. We studied the effects of different doses of a TD and LD on electrolytes, calcitropic hormones and biochemical bone markers.

Subjects and methods In a five‐period crossover study, comparing four active doses with placebo, 40 postmenopausal women with osteopenia were treated with different doses of LD bumetanide (n = 20, 0·5–2·0 mg per day) or TD bendroflumethiazide (n = 20, 2·5–10 mg per day). Each treatment period lasted 1 week.

Results Urinary calcium decreased dose‐dependently in response to the bendroflumethiazide. The best hypocalciuric effect was achieved by 5 mg day−1 of bendroflumethiazide. Total plasma calcium levels increased, whereas ionised calcium at ambient pH‐values decreased because of increased pH‐values in response to the bendroflumethiazide. Plasma PTH levels did not change, whereas a slight dose‐dependent increase occurred in plasma 1,25(OH)2D levels. As a marker of bone formation, plasma osteocalcin levels increased. Conversely, bumetanide dose‐dependently increased renal calcium losses with a concomitant increase in plasma PTH and 1,25(OH)2D levels. Plasma osteocalcin levels increased and bone‐specific alkaline phosphatase levels decreased dose‐dependently.

Conclusion Whether a LD or TD is chosen as diuretic therapy affects calcium homeostasis. The effects of LDs are potentially harmful to bone. Further studies are needed to evaluate whether long‐term treatment with LDs causes osteoporosis. Until then, we suggest using, if possible, a TD rather than a LD as diuretic therapy in order not to risk deleterious effects on bone metabolism.
Intima media thickness of carotid arteries is reduced in heterozygous carriers of the Gly972Arg variant in the insulin receptor substrate‐1 gene
Authors: Hölzl B. , Iglseder B. , Stadlmayr A. , Hedegger M. , Moré E. , Reiter R. , Sandhofer F. , Paulweber B.
Published: March 2003

Background The Gly972Arg mutation in the IRS‐1 gene has been found to be associated with insulin resistance and type II diabetes. A recently published study described an association between the Arg allele and an increased risk for coronary artery disease. In the present study we asked whether the presence of the codon 972 mutation in the IRS‐1 gene is associated with higher IMT values of the carotid arteries.

Materials and methods To address this question, genotypes of the codon 972 polymorphism were determined in 1018 healthy unrelated individuals aged 40–65 years. Three homozygous carriers of the mutation were excluded for statistical analysis. In all subjects, intima media thickness (IMT) and B‐scores of carotid arteries as well as a large number of metabolic parameters were determined.

Results Heterozygous carriers of the Arg972 allele exhibited significantly lower IMT and B‐score values than noncarriers. Total cholesterol, LDL‐cholesterol and serum levels of apolipoprotein B were significantly lower in the carriers. Furthermore, a significant interaction between Gly972Arg‐carrier status and mean daytime 24‐h systolic blood pressure with regard to IMT could be observed; carriers with a systolic blood pressure above the median had lower IMT values than carriers with a systolic blood pressure equal or below the median. All these effects were more pronounced in females and remained significant after adjustment for sex, age, BMI, systolic blood pressure and serum apolipoprotein B levels. No significant differences between the carriers and the noncarriers could be found for BMI, insulin sensitivity or frequency of type II diabetes.

Conclusions The results of our study demonstrate that the presence of the Arg972 allele is associated with lower IMT values of the carotid arteries. This finding is partly explained by lower serum levels of apolipoprotein B in carriers. The protective effect of the Gly972 Arg mutation seems to be stronger in the presence of a higher systolic blood pressure. Our data contradict previous findings suggesting an increased risk for insulin resistance, type II diabetes and atherosclerotic vascular disease in carriers of the mutation.
Polymorphism within the HLA‐DQB1*02 promoter associated with susceptibility to coeliac disease
Authors: Fernandez‐Arquero M. , Caldés T. , Casado E. , Maluenda C. , Figueredo M. A. , De La Concha E. G.
Published: March 2003

Susceptibility to coeliac disease is associated with a particular HLA‐DQαβ heterodimer encoded by the DQA1*0501 and DQB1*02 genes. A single base polymorphism in the DQB1*02 promoter region in DR7, DQA1*0201, DQB1*02 haplotypes was observed, associated with an increased susceptibility to the disease. This finding suggests a novel mechanism of susceptibility to immune‐mediated diseases.
Lack of HLA‐G soluble isoforms in Graves‐Basedow thyrocytes and complete cDNA sequence of the HLA‐G*01012 allele
Authors: Castro M. J. , Morales P. , Catálfamo M. , Fernández‐Soria V. , Suárez B. , Varela P. , Pérez‐Blas M. , Alvarez M. , Jaraquemada D. , Arnaiz‐Villena A.
Published: March 2003

The presence of HLA‐G mRNA has been studied in thyroid follicular cells from autoimmune patients with Graves’ disease. Investigating the possible role of the expression of the HLA‐G gene in tissue inflammation, we have found four of the six HLA‐G mRNA isoforms described: G1, G2, G3 and G4, but not the soluble ones G5 and G6. Soluble G isoforms may be responsible for inducing tolerance and inflammation control and their absence in autoimmune thyroid follicular cells may induce failure of such control. In addition, the complete coding sequence of HLA‐G*01012 has been obtained from thyrocytes and it shows only four synonymous changes with respect to the HLA‐G*01011 allele; this further supports the existence of an evolutionary pressure for invariance on HLA‐G genes.
Description of two Mhc‐C‐related sequences in the New World monkey Saguinus oedipus*
Authors: Álvarez‐Tejado M. , Martínez‐Laso J. , García‐de‐la‐Torre C. , Varela P. , Recio M. J. , Allende L. , Gómez‐Casado E. , Arnaiz‐Villena A.
Published: March 2003

Two new Mhc class I partial exon 1, intron 1, exon 2, intron 2 and partial exon 3 DNA sequences from the New World monkey Saguinus oedipus (Saoe) are described. These two sequences show certain Mhc‐C sequence‐specific changes. The only difference between these two new sequences is a productive substitution at position 152 [GCG (Ala)→GAG (Glu)]. This change occurs in a position which in Mhc classical class I molecules affects the interaction between the peptide and the T‐cell receptor. A dendrogram with Mhc sequences from different loci and different species was constructed, which clearly shows that these two new sequences cluster closer to Mhc‐C sequences than to others. These data suggest that the new sequences may be related to the Mhc‐C locus, and they have been named Mhc‐Saoe‐CR*01 and ‐CR*02. However, they share only a few of the conserved residues (from gorilla to human) of Mhc‐C sequences, which suggests that the relationships with an ancestor of the Mhc‐C lineage are very distant or that these two sequences are products of convergent evolution to perform a C locus related function. Furthermore, in the fragment of DNA sequenced, there is a loss of two invariant residues conserved in antigen‐presenting molecules from reptiles to humans; thus, it is unlikely that these two Mhc‐C‐like sequences have an antigen‐presenting function, or even that they are two alleles of a pseudogene; however, the G + C percentage (86.1%) at the third base of codons approaches that of an expressed gene in Saoe. It is concluded that Mhc molecules with C‐locus characteristics existed in primates 50 million years ago and that this does not support a more recent origin of Mhc‐C genes.
Mannose binding lectin (MBL) genotype distributions with relation to serum levels in UK Caucasoids
Authors: Crosdale D. J. , Ollier W. E. R. , Thomson W. , Dyer P. A. , Jensenious J. , Johnson R. W. G. , Poulton K. V.
Published: March 2003

Mannose binding lectin (MBL) gene and promoter‐region polymorphisms contribute to a reduction in the levels of circulating MBL in a number of ways. Promoter polymorphisms affect the levels of MBL produced, whilst structurally encoding mutations cause non‐functional protein to be assembled and subsequently degraded. MBL is important as a protein of the innate immune system in both the clearance of potential pathogens and the activation of the complement cascade. Using variations of SSP‐PCR amplifications and SSO probing techniques, we have produced MBL‐polymorphism haplotype and genotype profiles of a series of high‐level MBL‐producing, low‐level MBL‐producing and random individuals taken from a population of 800 UK Caucasoid controls. Structurally encoding mutant alleles were more frequent within the low‐level producing cohort when compared to both high‐level producers and the randomly selected sample. However, not all low‐level producers could be accounted for by the possession of low‐level encoding haplotypes. This may be due to the presence of additional, undetected polymorphisms governing MBL production, or another external factor that may influence the transcriptional regulation of the gene.
Lack of association between HLA genotype and chronic fatigue syndrome
Authors: Underhill J. A. , Mahalingam M. , Peakman M. , Wessely S.
Published: March 2003

Although the aetiology of chronic fatigue syndrome is controversial, evidence that infective agents including viruses may have a role in the development of the condition has led to studies seeking an association with the immunomodulatory HLA genes. In the present study, we sought to extend previous work using a well‐characterized patient group and modern HLA genotyping techniques. Fifty‐eight patients were phenotyped for HLA A and B by microcytotoxicity and genotyped for HLA DRB, DQB and DPB by PCR oligoprobing, and the frequencies of antigens so assigned were compared with those from a control group of 134. No significant differences in HLA frequencies were found between patient and control groups. Thus, this study does not confirm previous findings of an HLA association with chronic fatigue syndrome, suggesting that neither presentation of viral antigen by HLA class I nor antigen processing genes in the HLA region is a major contributory factor in the development of the disease.
Codominant expression of the polymorphic MICA alloantigens encoded by genes in the HLA region
Authors: Molinero L. L. , Marcos C. Y. , Mirbaha F. , Fainboim L. , Stastny P. , Zwirner N. W.
Published: March 2003

The HLA‐related, polymorphic MHC class I‐related chain A (MICA) gene encodes a 383‐amino acid polypeptide, with three extracellular domains (α1, α2 and α3), a transmembrane region and a cytoplasmic tail. We have previously shown that freshly isolated endothelial cells, fibroblasts, keratinocytes and monocytes express MICA, while peripheral blood CD4+, CD8+or CD19+lymphocytes do not. This polymorphic MICA molecule is a target for specific alloantibodies in sera from kidney, heart and lung transplant recipients, although its possible role during graft rejection remains to be demonstrated. In this study we investigated whether there is codominance in the expression of MICA. We isolated RNA from a heterozygous cell line (HCT116), previously shown by sequencing‐based typing to be MICA*001/MICA*00902, as well as 12 clones derived from it. Thereafter, we retrotranscribed the RNA into cDNA, and performed a molecular typing using MICA‐sequence specific oligonucleotides (SSOP). Using this approach, we detected the RNA encoding MICA*001 and MICA*00902 in all the clones and in the parental cell line, indicating that MICA is codominantly expressed. This codominant expression was further confirmed by cloning and sequencing plasmids encoding these two alleles produced from the same HCT116 RNA preparation. We also produced the two recombinant MICA proteins (MICA*001 and MICA*00902). They reacted with rabbit anti‐MICA polyclonal antibodies by ELISA and Western blot, indicating that the plasmids carrying the cDNA inserts probably encode functional MICA proteins. This strongly suggests that, like the HLA class I and class II proteins, MICA is codominantly expressed. The codominant expression of the polymorphic, HLA‐like MICA alloantigens may have implications for the immune response elicited by the allograft in organ transplantation.
Distribution of bovine lymphocyte antigen (BoLA‐DRB3) alleles in Brazilian dairy Gir cattle (Bos indicus)
Authors: Da Mota A. F. , Gabriel J. E. , Martinez M. L. , Coutinho L. L.
Published: March 2003

Brazilian dairy Gir (Bos indicus) cattle are a tropical, well‐adapted breed, for which no information on the major histocompatibility complex (MHC) is presently available. The second exon of the bovine lymphocyte antigen (BoLA‐DRB3) was amplified by polymerase chain reaction (PCR) of DNA samples from 28 Brazilian dairy Gir cows. Two experimental genotyping approaches were used: direct sequencing of PCR gene products (PCR‐DS) and sequencing of cloned PCR fragments (S‐CLO). Results demonstrate the viability of both typing approaches. PCR‐DS allowed typing of 39% of the animals while the remainder were genotyped by S‐CLO. Seventeen BoLA‐DRB3 alleles were assigned, including some that were only recently described for zebu cattle. Allelic frequencies ranged from 0.02 to 0.18. The most frequent alleles were *3601 (frequency = 0.18), *2201 (0.14) and *2101 (0.11).
FcgRIIA, FcγRIIIA and FcγRIIIB polymorphisms in Spanish patients with systemic lupus erythematosus
Authors: González‐Escribano M. F. , Aguilar F. , Sánchez‐Román J. , Núñez‐Roldán A.
Published: March 2003

Linkage studies on human families suggest that receptors for the Fc fragments of immunoglobulin G (IgG) (FcγRs) could be implicated in the susceptibility to, or the progression of, some autoimmune diseases. In this work we analyse the possible role of polymorphic variants of FcγRIIA, FcγRIIIA and FcγRIIIB genes in the susceptibility to systemic lupus erythematosus, the prototype systemic autoimmune disease. A total of 276 Spanish patients (34 male and 242 female) with systemic lupus erythematosus were included in this cross‐sectional study. The FcγRIIA‐131, FcγRIIIA‐176 and FcγRIIIB‐NA1/NA2 polymorphisms were investigated in the patient group as well as in 194 ethnically matched controls using polymerase chain reaction–amplification refractory mutation system (PCR‐ARMS). Statistical comparisons of genotype frequencies were performed using the χ2 test. In the case of the FcγRIIIB‐NA1/NA2 polymorphism, an increase in the frequency of homozygous NA2/NA2 in patients was found (61.2 vs. 51.0%; P = 0.03; OR = 1.5; 95% CI = 1.03–2.24), as well as a decrease in the frequency of the NA1/NA2 genotype (28 vs. 38.7%; P = 0.02; OR = 0.6; 95% CI = 0.41–0.92). These associations were independent of patient gender and HLA‐DRB1 specificities. With respect to the FcγRIIA‐131 and FcγRIIIA‐176 polymorphisms, no differences were found between patients and controls. Patient stratification according to their lupus‐related nephritis status gave similar genotypic distribution patterns in both disease categories in all the cases.
Association analysis of polymorphisms in the interleukin‐4 receptor (alpha) gene with atopic asthma in patients from western Mexico
Authors: Mújica‐López K. I. , Flores‐Martínez S. E. , Ramos‐Zepeda R. , Castañeda‐Ramos S. A. , Gazca‐Aguilar A. , García‐Pérez J. , Sánchez‐Corona J.
Published: March 2003

We undertook an association analysis between the ile50val, glu375ala, cys406arg, and ser761pro polymorphisms of the IL‐4Rα gene and atopic asthma, total IgE levels and IL‐4 serum levels in a population from western Mexico. We found that the ser761pro polymorphism was monomorphic for ser761, while there was no association between any of the other polymorphisms and the three phenotypes analysed.
Effects of dissolved organic matter on the mobility of copper in a contaminated sandy soil
Authors: TEMMINGHOFF E. J. M. , VAN DER ZEE S. E. A. T. M. , DE HAAN F. A. M.
Published: March 2003

Changes in land use can result in increased soil organic matter content, and decreases in Ca and pH which will affect the mobility of Cu in soil. We studied how the mobility and coagulation of dissolved organic matter and pH affected the mobility of Cu in contaminated sandy soil by batch and column experiments in the laboratory. The soil, with pH ranging from 3.8 to 5.7, had been polluted with Cu in the range 0.13–1.9 mmol kg−1 more than a decade ago. Calcium and Cu bound by dissolved organic matter (purified humic acid) was determined in the pH range 4–8; Cu2+ concentration ranged from 10−4 to 10−12M and Ca2+ concentration from 10−3 to 10−6M. Binding of Cu by dissolved organic matter as affected by Ca and pH could be predicted well with the non‐ideal competitive adsorption (NICA) model. Coagulation of dissolved organic matter was affected by the amount of trivalent (Al3+) and divalent (Ca2+ and Cu2+) cations in solution. There was little effect of pH on coagulation between pH 4 and 6. The concentration of the divalent cations, Ca2+ and Cu2+, at which coagulation of dissolved organic matter appeared could be explained by differences in the binding of Ca and Cu by dissolved organic matter. Binding of Cu by dissolved organic matter as well as by solid organic matter, both affected by Ca and pH, could be described well with the NICA model. We investigated the coagulation and mobility of dissolved organic matter in column experiments and found that they enhanced Cu mobility. Three processes, Cu desorption by soil, dissolved organic matter coagulation and Cu complexation by dissolved organic matter, act simultaneously in the soil columns. All three with counteracting effects on Cu mobility are influenced by Ca and pH and could be adequately represented by the multicomponent NICA model.
A re‐examination of closed flux chamber methods for the measurement of trace gas emissions from soils to the atmosphere
Authors: CONEN F. , SMITH K. A.
Published: March 2003

The most widely used method for measuring the emission of a trace gas such as N2O from soil to the atmosphere involves the accumulation of the gas under closed chambers followed by sampling and analysis (by gas chromatography or infrared methods). These chambers can affect the gas exchange, and so improved designs have been proposed. We have tested their performance. One design includes a vent tube to allow ambient pressure fluctuations to occur also inside the chamber. We tested it against a sealed version on two different grassland sites during N2O peak emissions in spring 1997. On a welldrained soil with a fairly large air permeability vented chambers yielded fluxes as much as five times those of sealed chambers, depending on wind speed. By contrast, on a heavier and wetter soil with smaller air permeability vented chambers averaged only 88% of the fluxes observed with sealed chambers. The effects of venting cannot be explained solely on the basis of mean pressure differences inside and outside the chamber. It seems more likely that wind blowing over the vent depressurizes the chamber (Venturi effect), resulting in significant gas flow from the more permeable soil into the interior of the chamber. The opposite trend for the less permeable soil suggests that diffusion losses through the vent tube are greater than the increase in concentration due to soil gas flow. Venting can create larger errors than the ones it is supposed to overcome.
Characterization of the porous structure of soils: adsorption of nitrogen (77 K) and carbon dioxide (273 K), and mercury porosimetry
Authors: Echeverría J. C. , Morera M. T. , Mazkiarán C. , Garrido J. J.
Published: March 2003

Accessibility of adsorbates to internal active sites of soils depends mainly on the porous structure of the material. We aimed to determine the distribution of pore sizes in soils with varied physico‐chemical properties, by combining adsorption of gases and mercury porosimetry. Microporosity was studied by physical adsorption of N2 at 77 K and CO2 at 273 K; mercury intrusion porosimetry allowed us to evaluate the macroporosity; and mesoporosity was determined by capillary condensation of N2 and mercury porosimetry. The soils investigated were essentially macroporous, with volumes between 0.33 and 0.73 cm3 g–1; the maxima in the differential pore‐size distribution were in the range 1500–4000 nm. Volumes of meso‐ or micropores were always less than 10% of macropore volumes. Calculations based on the theory of Dubinin and the αs‐method (for N2 at 77 K) provided, generally, coincident results. In a soil containing much organic matter, N2 adsorption was only one‐ninth that of CO2 adsorption, showing that N2 adsorption into the narrow micropores of organic matter was kinetically restricted. When accessibility to micropores was not restricted, the total volume of micropores could be deduced from N2 adsorption, whereas CO2 measured exclusively the narrowest microporosity.
Blocking the release of potassium from clay interlayers by small concentrations of NH4+ and Cs+
Authors: Springob G.
Published: March 2003

To understand the process and the kinetics of potassium release from the clay interlayer in natural and arable soils in more detail, I tested the hypotheses that large, monovalent cations, especially NH4+ and Cs+, can reduce the release rates of K+ which is exchanged by Ca2+, even if these monovalent cations are present in concentrations of only a few μm. Percolation experiments were carried out with different illitic soil materials, some containing vermiculite, with 5 m
m CaCl2 at pH 5.8 and 20°C, in some cases for over 7000 h.
NH4+ and Cs+ both caused a large decrease in the rate at which K+ was released, Cs+ especially. Suppression began at 5 μm
NH4+ Blocking by 20 μm
NH4+ was easily reversible: the release rates readily increased when
NH4+ was omitted from the exchange solution. Blocking by 2 μm Cs+ was equal to approximately 90% of that at 10 μm Cs+. Larger concentrations of Cs+ than 10 μm did not further reduce release but rather caused a slight increase, probably because of enhanced exchange of K+ by Cs+ without exfoliation of the interlayer space. Blocking by Cs+ was not reversible within > 7000 h of percolation by 5 m
m CaCl2. The blocking effect was reproduced in several different soil materials using 10 μm Cs+ but was most pronounced in vermiculite‐rich samples. As
NH4+ is present in most arable soils, at least in concentrations of a few μm, I conclude that the observed effects are of significance in the K dynamics processes in soils, for example near the roots of plants. Further, very small concentrations of Cs+ in exchange solutions containing a large background of Ca2+ appear to be useful for suppressing K+ release from the interlayer in laboratory studies, probably without significantly altering the exchange at outer mineral surfaces.
Response of sorption processes of MCPA to the amount and origin of organic matter in a long‐term field experiment
Authors: Haberhauer G. , Pfeiffer L. , Gerzabek M. H. , Kirchmann H. , Aquino A. J. A. , Tunega D. , Lischka H.
Published: March 2003

Changes in farming practices over long times can affect the sorption behaviour of MCPA ((4‐chloro‐2‐methylphenoxy)acetic acid). We studied the adsorption–desorption mechanisms of MCPA on soil with varied amounts and origins of soil organic matter obtained from a long‐term field experiment with various organic amendments. The origin of the soil organic matter seems to be crucial for the sorption behaviour of MCPA. Samples of soil amended with sewage sludge sorbed MCPA more strongly than the soil under any other treatment. Peat‐amended soil was second followed by soil receiving animal manure, green manure, mineral fertilizer without N and the fallowed soil. Both the carbon content and the origin of the organic matter are important for the sorption. A decrease of carbon content of a soil does not necessarily imply a reduction of sorption capacity for polar organic acids such as MCPA. Nevertheless, our adsorption–desorption experiments suggest that with decreasing carbon content the role of mineral sorption mechanisms could become more pronounced. Our results showed that interactions of soil organic matter and soil minerals distinctly influence adsorption properties for MCPA.
Aggregate strength and mechanical behaviour of a sandy loam soil under long‐term fertilization treatments
Authors: Munkholm L.J. , SchjØnning P. , Debosz K. , Jensen H. E. , Christensen B.T.
Published: March 2003

Current concern for soil quality has stimulated research on soil biological and chemical properties. In contrast, the mechanical behaviour of soil is somewhat neglected. We have examined the effects on soil mechanical properties of more than 100 years of contrasting fertilization employing three treatments from the Askov long‐term experiment: UNF (unfertilized), NPK (mineral fertilized) and AM (animal manured). We have measured tensile strength of aggregates when air‐dry and when adjusted to −10, −30 and −100 kPa pressure potential. Four aggregate size classes were investigated (1–2, 2–4, 4–8 and 8–16 mm diameter). Soil fragmentation was characterized in the field using a drop‐shatter test. Bulk soil strength was determined in the field using a shear vane and a torsional shear box. Soil texture, pH, cation exchange capacity and microbial biomass were measured. The unfertilized soil has little soil organic matter and microbial biomass and is dense. Its aggregates were strong when dry and weak when wet. In contrast, the manured soil had strong aggregates when wet and rather weak ones when dry. The NPK soil generally had intermediate properties. The differences between the soils when dry seem to be related to differences in dispersible clay content, whereas the differences when wet are related to differences in the amount of organic binding and bonding material. The optimal water content for tillage as well as the tolerable range in water content was largest in the manured soil and smallest in the unfertilized soil. Our results indicate that soil mechanical properties should be measured over a range of water regimes to determine the effects of various long‐term fertilization treatments.
Effect of rain on the macroporosity at the soil surface
Authors: Rousseva S. , Torri D. , Pagliai M.
Published: March 2003

Rain falling on soil causes slaking, mechanical disruption of aggregates and compaction. Too few data exist to predict the changes likely to occur in particular soil, landscape and management conditions. Experiments with simulated rain were set up to study and to model mathematically the changes of the pore system within the surface layer of a soil when rain was applied on a field cropped with maize. Macroporosity, pore‐size and pore‐shape distributions, and the pore volume were measured by image analysis of thin sections and the fractal dimensions of the pore surface roughness were estimated. The general trends of changes in porosity indicated the presence of two different sets of processes at the surface (0–3 cm) and in the layer immediately underneath (3–6 cm). In both layers most of the variation in macroporosity was due to a loss of elongated porosity. A theoretical approach recently developed to link rain and erosion to sealing properties was extended to describing the effect of rain on the elongated porosity and the pore volume fractal dimension in these two layers. The resulting set of equations describe in detail the evolution of soil porosity near the soil surface. Our approach could be useful when modelling the effects of sealing processes in soil erosion.
The isotopic composition of soil organic carbon on a north–south transect in western Canada
Authors: Bird M. , Santrùcková H. , Lloyd J. , Lawson E.
Published: March 2003

The minor isotopes of carbon (13C and 14C) are widely used as tracers in studies of the global carbon cycle. We present carbon‐isotope data for the 0–5 cm layer of soil on a transect from 49.6°N to 68°N, from mature forest and tundra ecosystems in the boreal‐arctic zone of interior western Canada. Soil organic carbon in the < 2000 μm fraction of the soil decreases from 3.14 kg m−2 in the south to 1.31 kg m−2 in the north. The 14C activity of the organic carbon decreases as latitude increases from 118.9 to 100.7 per cent modern carbon (pMC). In addition, the 14C activities of organic carbon in the particle‐size fractions of each sample decrease as particle size decreases. These results suggest that organic carbon in the 0–5 cm layer of these soils transfers from standing biomass into the coarsest size fractions of the soil and is then degraded over time, with the residue progressively transferred into the more resistant finer particle sizes. We calculate residence times for the coarsest size fractions of 21 years in the south to 71 years in the north. Residence times for the fine size fractions (< 63 μm) are considerably longer, ranging from 90 years in the south to 960 years in the north. The δ13C of the organic carbon decreases from −26.8 ± 0.3‰ in soil under forest in the south to −26.2 ± 0.1‰ for tundra sites in the north. At all sites there is an increase in δ13C with decreasing particle size of 0.7–1.6‰. These changes in δ13C are due to the presence of ‘old’ carbon in equilibrium with an atmosphere richer in 13C, and to the effects of microbial degradation.
Effects of HCl–HF purification treatment on chemical composition and structure of humic acids
Authors: Sánchez‐ Monedero M. A. , Roig A. , Cegarra J. , Bernal M. P. , Paredes C.
Published: March 2003

Sample preparation for the study of humic acids involves a purification treatment to remove both mineral and organic components extracted along with the humic substances. The effects of HCl–HF purification on the chemical composition and structure of humic acids were studied in samples from eight different composts. Only small increases in the concentrations of C, N and H and a decrease in O were found in purified humic acids when compared with the unpurified materials, no more than 10% of average concentration. Total and phenolic acidity increased in the purified materials, whereas carboxylic and carbonyl acidity showed no statistically significant differences as a result of the purification. Gel permeation chromatography showed that only minor changes occurred in molecular size distribution of the humic acids, and the infrared spectra showed no appreciable differences between the purified humic acids and the untreated materials. We conclude that the HCl–HF treatment successfully reduced the ash contents of the humic acids without modifying their chemical composition and structure significantly.
Changes in soil chemistry and aggregate stability induced by fertilizer applications, burning and trash retention on a long‐term sugarcane experiment in South Africa
Authors: Graham M. H. , Haynes R. J. , Meyer J. H.
Published: March 2003

Throughout the world there is a trend towards retaining crop residues rather than burning them. For this reason, changes in soil chemistry and aggregation in a Vertisol induced by 59 years of burning or green cane harvesting with or without annual fertilizer applications were investigated. Crop residues were either burnt prior to harvest with the harvest residues raked off (R1), burnt prior to harvest with the harvest residues left on the soil surface (R2), or left unburnt with all the trash left on the soil surface (R3). Concentrations of organic C in the surface 10 cm of soil increased with fertilizer applications and with increasing amounts of crop residue returned in the order R1 < R2 < R3. Fertilizer applications caused an accumulation of residual P in both inorganic (Pi) and organic (Po) forms. A sequential P fractionation showed that fertilizer P accumulated in both labile and recalcitrant Pi and Po forms, and trash retention caused an accumulation of recalcitrant Po. Concentrations of K decreased in the unfertilized R1and R2treatments because K reserves were depleted. By contrast, there was an increase in the concentrations of K in the fertilized R3treatment. The soil became more acid on the fertilized and, to a lesser extent, trash retention plots. We attribute this to nitrification and subsequent nitrate leaching. Acidification resulted in a loss of exchangeable Ca and Mg, a decrease in ECEC, and an increase in the concentrations of total and monomeric Al in soil solution, in exchangeable Al3+and in the buffering reserve of non‐exchangeable Al associated with organic matter. Aggregate stability was increased by increasing crop residues but decreased by fertilizer applications. The decrease was attributed to an increase in the proportion of exchangeable cations present in monovalent form due to applications of fertilizer K and leaching of Ca and Mg. We conclude that trash retention and annual fertilizer applications have substantial long‐term effects on both organic matter status and soil pH and therefore on other soil chemical and physical properties.