bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of high doses of glucocorticoids on free amino acids, ribosomes and protein turnover in human muscle
Authors: Löfberg E. , Gutierrez A. , Wernerman J. , Anderstam B. , Mitch W. E. , Price S. R. , Bergström J. , Alvestrand A.
Published: March 2003

Background  Treatment with glucocorticosteroids causes a negative nitrogen balance, but the kinetic mechanisms responsible for this catabolic effect are controversial. We investigated the effects of 60 mg day−1 prednisolone on protein synthesis and degradation in human skeletal muscle.

Materials and methods Healthy adults (n = 9) were studied in the postabsorptive state, before and after 3 days of prednisolone treatment. The L‐[ring 2,6‐3H5]‐phenylalanine tracer technique, concentration and size distribution of the ribosomes, mRNA content of the ubiquitin‐proteasome pathway components in muscle, phenylalanine flux across the leg, and the free amino acid concentrations in skeletal muscle were used to study muscle protein metabolism.

Results The concentrations of most amino acids in arterial blood increased after prednisolone. There were also increased effluxes of phenylalanine, asparagine, arginine, alanine, methionine and isoleucine from the leg. The rate of protein degradation, as measured by the appearance rate (Ra) of phenylalanine, increased by 67% (P = 0·023) which, together with a doubling of the net release of phenylalanine from the leg (P = 0·007), indicated accelerated protein degradation. The pathway was not identified but there was no significant increase in mRNAs’ encoding components of the ubiquitin‐proteasome pathway. There was a 6% reduction in polyribosomes (P = 0·007), suggesting a decrease in the capacity for protein synthesis, although there was no measured decrease in the rate of protein synthesis.

Conclusions  These findings indicate that high doses of prednisolone lead to a sharp increase in net protein catabolism, which depends more on enhanced protein breakdown, and an uncertain effect on protein synthesis. The mechanisms stimulating proteolysis and the pathway stimulated to increase muscle protein degradation should be explored.
Cyclooxygenase‐2‐positive macrophages infiltrate the Alzheimer’s disease brain and damage the blood–brain barrier
Authors: Fiala M. , Liu Q. N. , Sayre J. , Pop V. , Brahmandam V. , Graves M. C. , Vinters H. V.
Published: March 2003

Background Monocyte/macrophages are known to infiltrate the brain of patients with HIV‐1 encephalitis (HIVE). In Alzheimer’s disease brain, the origin of activated microglia has not been determined.

Materials and methods We employed the antigen retrieval technique, immunocytochemistry, immunofluorescense, and confocal microscopy to identify macrophages and microglia in relation to amyloid‐β plaques and the blood–brain barrier in autopsy brain tissues from patients with Alzheimer’s disease (AD) and HIVE.

Results In both conditions, cyclooxygenase‐2 positive macrophages and, to a lesser degree, T and B cells infiltrate brain perivascular spaces and neuropil. The macrophages are distinguishable from ramified microglia, and decorate the vessels at the sites of apparent of endothelial tight junction protein ZO‐1 disruption. The macrophages also infiltrate amyloid‐β plaques, display intracellular amyloid‐β and are surrounded by amyloid‐β‐free lacunae. Furthermore, the macrophages partially encircle the walls of amyloid‐β‐containing vessels in amyloid angiopathy, and exhibit intracellular amyloid‐β but not paracellular lacunae. Significantly larger zones of fibrinogen leakage surround the microvessels in HIVE brain tissues compared with AD tissues (P = 0·034), and AD tissues have significantly greater leakage than control tissues (P = 0·0339). The AD group differs from a normal control age‐matched group with respect to both the area occupied by CD68 (P = 0·03) and cyclooxygenase‐2 immunoreactive cells (P = 0·004).

Conclusion In both HIVE and AD, blood‐borne activated monocyte/macrophages and lymphocytes appear to migrate through a disrupted blood–brain barrier. The lacunae around macrophages in amyloid‐β plaques but not in vessel walls are consistent with the ability of macrophages to phagocytize and clear amyloid‐β deposits in vitro.
11b‐hydroxysteroid dehydrogenase activity in proteinuric patients and the effect of angiotensin‐II receptor blockade
Authors: Kerstens M. N. , Buter H. , Navis G. J. , Dullaart R. P. F.
Published: March 2003

Background It has been suggested that an altered setpoint of the 11βHSD‐mediated cortisol to cortisone interconversion towards cortisol contributes to sodium retention in nephrotic syndrome patients. We studied the parameters of 11βHSD activity in proteinuric patients, in particular its activity at the kidney level. We also studied the effect of angiotensin‐II receptor blockade on the parameters of 11βHSD activity.

Materials and methods Serum cortisol/cortisone ratio and the urinary ratios of (tetrahydrocortisol + allo‐tetrahydrocortisol)/tetrahydrocortisone [(THF + allo‐THF)/THE] and of urinary free cortisol/free cortisone (UFF/UFE) were measured in eight proteinuric patients and compared with eight matched, healthy subjects. Patients were subsequently studied after 4 weeks’ treatment with losartan 50 mg day−1 and placebo, respectively.

Results No significant differences between the proteinuric patients and the healthy subjects were observed in the serum cortisol, serum cortisone, serum cortisol to cortisone ratio, or in the urinary excretions of THF, allo‐THF, THE, sum of cortisol metabolites, or the (THF + allo‐THF)/THE ratio. Urinary free cortisol excretion and the UFF/UFE ratio were lower in the proteinuric patients than in the healthy subjects (56 ± 21 vs. 85 ± 24 pmol min−1, P < 0·05, and 0·39 ± 0·07 vs. 0·63 ± 0·28, P < 0·05, respectively). Mean arterial pressure and proteinuria were reduced significantly during losartan treatment, but without concomitant changes in peripheral cortisol metabolism.

Conclusions Increased renal inactivation of cortisol in proteinuric patients does not support the contention that altered 11βHSD activity contributes to sodium retention in patients with nephrotic syndrome. Losartan 50 mg d.d. reduces mean arterial pressure and proteinuria, but does not exert a significant effect on the cortisol to cortisone interconversion.
Molecular study of electron transfer flavoprotein α‐subunit deficiency in two Japanese children with different phenotypes of glutaric acidemia type II
Authors: Purevjav E. , Kimura M. , Takusa Y. , Ohura T. , Tsuchiya M. , Hara N. , Fukao T. , Yamaguchi S.
Published: March 2003

Background Electron transfer flavoprotein is a mitochondrial matrix protein composed of alpha‐ and beta‐subunits (ETFα and ETFβ, respectively). This protein transfers electrons between several mitochondrial dehydrogenases and the main respiratory chain via ETF dehydrogenase (ETF‐DH). Defects in ETF or ETF‐DH cause glutaric acidemias type II (GAII).

Materials and methods We investigated the molecular basis of ETFα deficiency in two Japanese children with different clinical phenotypes using expression study.

Results Patient 1 had the severe form of GAII, a compound heterozygote of two mutations: 799G to A (αG267R) and nonsense 7C to T (αR3X). Patient 2 had the mild form and carried two heterozygous mutations: 764G to T (αG255V) and 478delG (frameshift). Both patients had one each of missense mutations in one allele; the others were either nonsense or truncated. Restriction enzyme digestion assay using genomic DNAs from 100 healthy Japanese revealed that these mutations were all novel. No signal for ETFα was detected by immunoblotting in cases of missense mutants, while wild‐type cDNA resulted in expression of ETFα protein. Transfection with wild‐type ETFα cDNA into cultured cells from both patients elevated incorporation of radioisotope‐labelled fatty acids.

Conclusion These four mutations were pathogenic for GAII and missense mutations, αG255V and αG267R were considered anecdotal for mild and severe forms, respectively.
Polymorphisms of genes affecting thrombosis and risk of myocardial infarction
Authors: Kakko S. , Elo T. , Tapanainen J. M. , Huikuri H. V. , Savolainen M. J.
Published: March 2003

Background  As thrombosis is an essential factor in the pathogenesis of acute myocardial infarction (AMI), the genes of proteins affecting haemostasis are good candidate genes for AMI.

Design  Associations of the known polymorphisms of the coagulation factor VII (FVII) gene (R353Q), the coagulation factor XIII (FXIII) gene (V34L) and the glycoprotein Ia (Gp1a) gene (C807T) with the occurrence of AMI were studied in 142 AMI survivors and 142 age‐ and sex‐matched control subjects.

Results  Among those who smoked, the L34 allele of the amino acid FXIII polymorphism was less common in the AMI patients (16%) than in the controls (27%) (P = 0·06), suggesting a possible interaction of AMI risk between the FXIII genotype and smoking status. No differences in the allele or genotype frequencies of the studied polymorphisms were seen between the whole study groups. Logistic regression analysis showed the carriers of the L34 allele of the FXIII amino acid polymorphism to have a significantly (P = 0·03) lower AMI risk compared with those homozygous for the V34 allele (odds ratio = 0·54, 95% confidence interval 0·31‐0‐93).

Conclusion  The L34 allele of the amino acid polymorphism of the FXIII gene is associated with a decreased risk of AMI, and this protecting association seems to be more pronounced in smokers.
Time‐dependent effect of statins on platelet function in hypercholesterolaemia
Authors: Puccetti L. , Pasqui A. L. , Pastorelli M. , Bova G. , Cercignani M. , Palazzuoli A. , Angori P. , Auteri A. , Bruni F.
Published: March 2003

Background Reduction of platelet activity induced by statins has been described as a positive effect exerted by such molecules on vascular thrombotic events. However, the relations among cholesterol (LDL‐C) reduction, the timing of the antiplatelet effect, the involved mechanisms and the doses of each statin able to reduce platelet function are not actually well known. The aim of our study was to evaluate the impact of simvastatin (20 mg day−1), atorvastatin (10 mg day−1), fluvastatin (40 mg day−1) and pravastatin (40 mg day−1) on platelet function in hypercholesterolaemic subjects with relation to (LDL‐C), oxidized‐LDL (ox‐LDL) and antiport mechanism modifications.

Materials and methods Sixteen subjects were assigned to each treatment (40 males, 24 females, mean age 48·7 ± 13·4, LDL‐C 5·13 ± 0,23 mmol L−1) and evaluated for platelet surface P‐selectin (P‐sel), lipid profile, ox‐LDL, platelet‐associated ox‐LDL (Pox‐LDL), platelet cholesterol content, antiport mechanisms, and intracellular and systemic NO synthase every 7 days for one month.

Results Our data show a strong relation between enhanced P‐sel and Pox‐LDL (r = 0·68, P < 0·01). Simvastatin, atorvastatin, fluvastatin and pravastatin reduce platelet activity after 1, 2, 3 and 4 weeks of treatment, respectively (P < 0·001, P < 0·001, P < 0·01, P < 0·05). Pox‐LDL are modulated early by simvastatin, atorvastatin and fluvastatin Pox‐LDL (r = 0·66, 0·65 and 0·52; P < 0·001, 0·001 and 0·01, respectively) whereas LDL‐C and ox‐LDL reductions associated to modifications of antiport activity act later. Moreouer, they are the most relevant finding in pravastatin‐related subjects.

Conclusions  Our data suggest a different impact of several statins on platelet function, which is initially related to interference with Pox‐LDL rather than LDL‐C reduction.
Iron does not bind to the Apo‐B protein of low‐density lipoprotein
Authors: De Valk B. , Leus F. R. , Voorbij H. A. M. , Marx J. J. M.
Published: March 2003

Background Epidemiological and experimental evidence suggests that (nontransferrin‐bound) iron plays an important role in atherogenesis by catalysing peroxidation of low‐density lipoprotein (LDL). However, the mechanism of the interaction of iron and LDL is unclear. Iron has to be in the closest vicinity of LDL in order to catalyse the formation of the short‐lived hydroxyl. In this study we investigated whether iron can bind to LDL in order to facilitate LDL peroxidation.

Methods LDL and [59Fe]ferric citrate were incubated at 37 °C and pH 7·4 for 30 min. Unbound [59Fe]ferric citrate was separated from LDL using a Sephadex G25‐M column. Activity of [59Fe]ferric citrate was measured in the collected fractions. A control experiment was performed using albumin instead of LDL.

Results and conclusion No binding was observed between iron, as a low molecular weight Fe(III) complex, and LDL. As a control albumin was able to bind iron, it seems evident that interaction of iron with LDL will involve other iron complexes.
Oxidative status and malondialdehyde in β‐thalassaemia patients
Authors: Cighetti G. , Duca L. , Bortone L. , Sala S. , Nava I. , Fiorelli G. , Cappellini M. D.
Published: March 2003

Background In β‐thalassaemia syndromes, decreased or impaired biosynthesis of β‐globin leads to accumulation of unpaired α‐globin chains. Moreover, the iron overload in β‐thalassaemia patients generates oxygen‐free radicals and peroxidative tissue injury. The aim of this study was to detect and correlate iron overload parameters with the oxidative stress and the antioxidant capability in β‐thalassaemia patients.

Design Serum iron, transferrin saturation, serum ferritin, nontransferrin‐bound iron (NTBI), levels of serum free and total (free + bound) malondialdehyde (MDA) and total peroxyl radical‐trapping antioxidant parameter (TRAP) were evaluated in 21 regularly transfused β‐thalassaemia major (TM) patients, 13 untransfused β‐thalassaemia intermedia (TI) patients and 17 healthy controls. Blood from the TM patients was drawn 48 h after the last desferoxamine (20–40 mg kg−1) infusion and just before transfusion.

Results Free and total MDA and NTBI levels were higher in the TM patients than in the TI. In the TM patients the free MDA levels correlated positively with serum iron (r = +0·3, P = 0·0006), whereas the total MDA correlated positively with NTBI (r = +0·45, P = 0·037). However, a negative correlation was observed between TRAP and NTBI (r = −0·4, P = 0·0006). In the TI patients there was no significant correlation between free or total MDA and TRAP or NTBI.

Conclusions Our results confirm the peroxidative status generated by iron overload in thalassaemia patients and highlight the rapid formation of marked amounts of free MDA despite the chelation therapy in TM patients.
Effects of age on the cardiac and vascular limbs of the arterial baroreflex
Authors: Brown C. M. , Hecht M. J. , Weih A. , Neundörfer B. , Hilz M. J.
Published: March 2003

BackgroundHealthy ageing has several effects on the autonomic control of the circulation. Several studies have shown that baroreflex‐mediated vagal control of the heart deteriorates with age, but so far there is little information regarding the effect of ageing on sympathetically mediated baroreflex responses. The aim of this study was to assess the effects of ageing on baroreflex control of the heart and blood vessels.

Materials and MethodsIn 40 healthy volunteers, aged 20–87 years, we applied oscillatory neck suction at 0·1 Hz to assess the sympathetic modulation of the heart and blood vessels and at 0·2 Hz to assess the effect of parasympathetic stimulation on the heart. Breathing was maintained at 0·25 Hz. Blood pressure, electrocardiographic RR intervals and respiration were recorded continuously. Spectral analysis was used to evaluate the magnitude of the low‐frequency (0·03–0·14 Hz) and high‐frequency (0·15–0·50 Hz) oscillations in the RR interval and blood pressure. Responses to neck suction were assessed as the change in power of the RR interval and blood pressure fluctuations at the stimulation frequency from baseline values.

ResultsResting low‐ and high‐frequency powers of the RR interval decreased significantly with age (P < 0·01). However, the low‐frequency power of systolic blood pressure did not correlate with age. Spontaneous baroreflex sensitivity (alpha‐index) showed a significant inverse correlation with age (r = −0·46,P < 0·05). Responses of the RR interval and systolic blood pressure to 0·1 Hz neck suction stimulation were not related to age, however, the RR interval response to 0·2 Hz neck suction declined significantly with age (r = −0·61,P < 0·01).

ConclusionsThese results confirm an age‐related decrease in cardiovagal baroreflex responses. However, sympathetically mediated baroreflex control of the blood vessels is preserved with age.
Vitamin D receptor gene polymorphism BsmI is not associated with the prevalence and severity of CAD in a large‐scale angiographic cohort of 3441 patients
Authors: Ortlepp J. R. , Von Korff A. , Hanrath P. , Zerres K. , Hoffmann R.
Published: March 2003

Background Recent studies found a relationship between Vitamin D and atherosclerosis. A common genetic polymorphism of the Vitamin D receptor (VDR) has been associated with coronary artery disease (CAD) in small study populations. To assess its influence on the prevalence and severity of CAD we studied a large‐scale population.

Methods A total of 3441 consecutive patients were referred for diagnostic coronary angiography. The BsmI Vitamin D receptor polymorphism was analyzed by polymerase chain reaction. Angiography was used to define phenotypes with clear coronary arteries (n = 775), coronary sclerosis (diameter stenosis < 50%; n = 579), CAD (diameter stenosis > 50% in at least one vessel; n = 1524). Patients with CAD at a young age (females aged less than 65 years, males aged less than 55 years; n = 563) were specially defined as premature CAD. The risk profile of traditional cardiovascular risk factors was obtained for every patient.

Results The genotype frequencies of the VDR BsmI polymorphism did not differ between all four phenotypes (P = 0·756). The allele frequencies for the B allele were 0·43 vs. 0·44 vs. 0·42 vs. 0·45 in the four phenotypic groups (P = 0·827). All traditional cardiovascular risk factors (hypercholesterolaemia, smoking, hypertension, diabetes mellitus, severe obesity, male gender) were significantly (P < 0·001) associated with the angiographic phenotype.

Conclusions The VDR gene variant BsmI was not associated with prevalence and severity of CAD in a large‐scale cohort phenotyped by angiography.
Identifying the links between obesity, insulin resistance and β‐cell function: potential role of adipocyte‐derived cytokines in the pathogenesis of type 2 diabetes
Authors: Greenberg A. S. , McDaniel M. L.
Published: March 2003

A combination of insulin resistance and pancreatic β‐cell dysfunction underlies most cases of type 2 diabetes. While the interplay of these two impairments is believed to be important in the development and progression of type 2 diabetes, the mechanisms involved are unclear. A number of factors have been suggested as possibly linking insulin resistance and β‐cell dysfunction in the pathogenesis of type 2 diabetes mellitus. Pro‐inflammatory cytokines such as tumour necrosis factor‐α (TNF‐α) have deleterious effects on both glucose homeostasis and β‐cell function, and can disrupt insulin signalling pathways in both pancreatic β cells and liver and adipose tissue. The anti‐inflammatory activity of the thiazolidinedione anti‐diabetic agents is potentially beneficial, given the possible role of pro‐inflammatory cytokines in linking insulin resistance with β‐cell dysfunction.
HLA class II (DRB1, DQA1 and DQB1) associated genetic susceptibility in Iranian multiple sclerosis (MS) patients
Authors: Amirzargar A. , Mytilineos J. , Yousefipour A. , Farjadian Sh. , Scherer S. , Opelz G. , Ghaderi A.
Published: March 2003

The association of HLA class II alleles with multiple sclerosis (MS) has been amply documented. In the present study, the role of HLA class II (DRB1, DQA1 and DQB1) alleles and haplotypes was investigated in 43 unrelated Iranian chronic progressive multiple sclerosis (CP‐MS) patients compared with 100 healthy individuals. HLA typing for DRB1, DQA1 and DQB1 was performed by restriction fragment length polymorphism (RFLP). Subtypes of DR4, DR15 and DR16 were defined using polymerase chain reaction (PCR) amplification with sequence‐specific primers (PCR‐SSP). The results show that, among DR2‐positive MS patients and the control group, a positive association with the DRB1*1503, DQA1*0102, DQB1*0602 haplotype (21% vs. 2.7%, P=0.057, RR=9.8) and a negative association with the most frequent DR15 haplotype in the control group, DRB1*15021, DQA1*0103, DQB1*0601 (7% vs. 24.3%, P=0.001), were observed. No significant association was found with the analysed HLA‐DRB1, DQA1 and DQB1 alleles.
Complement C4B null allele status confers risk for systemic lupus erythematosus in a Spanish population
Authors: Naves M. , Hajeer A. H. , Teh L. S. , Davies E. J. , Ordi‐Ros J. , Perez‐Pemen P. , Vilardel‐Tarres M. , Thomson W. , Worthington J. , Ollier W. E. R.
Published: March 2003

Genetic susceptibility to systemic lupus erythematosus (SLE) may vary amongst different populations. In UK patients, genes encoded in the HLA class II (DQA*0501/DRB1*0301) and class III [C4A*Q0 and tumour necrosis factor (TNF) polymorphisms] subregions appear to contribute to disease susceptibility. We have examined HLA‐DRB1, C4 and TNF microsatellites in 50 Spanish SLE patients and 48 matched controls. HLA‐DRB1*0301 was increased in patients but did not achieve statistical significance (41% vs. 25.5%). C4A*Q0 was not increased in patients, but C4B*Q0 allele frequency was significantly increased compared with the controls (29% vs. 6%; OR: 6.0). TNF c2 microsatellite allele frequency was also increased in SLE patients. The C4B null allele (C4B*Q0) appears to play an important role in SLE susceptibility in the Spanish population.
Mutation screening of the interferon‐gamma gene as a candidate gene for multiple sclerosis
Authors: Giedraitis V. , He B. , Hillert J.
Published: March 2003

Interferon‐γ (IFN‐γ) plays a crucial role in the regulation of the immune response. Alterations in IFN‐γ production have been found in several diseases including multiple sclerosis (MS). Such alterations could be caused by the action of different factors on cytokine production, or, theoretically, by mutations in the gene. We screened the IFN‐γ gene promoter and part of the first intron, known to contain a c‐Rel specific enhancer, for possible mutations by sequencing. We found a C to T substitution in the IFN‐γ promoter at position –333. Screening for this mutation by sequence‐specific PCR in 214 MS patients and 164 controls identified two patients, both heterozygous, but no controls with this mutation. No mutations were found in the first intron. The interferon‐γ gene is highly conserved and changes in IFN‐γ expression are probably due to the influence of regulatory factors on gene transcription, rather than gene polymorphisms.
The BglII polymorphism of the human prolactin gene lies within intron C and can be detected by PCR/RFLP
Authors: Stevens F. R. A. , Hajeer A. , John S. , Thomson W. , Worthington J. , Davis J. R. E. , Ollier W. E. R.
Published: March 2003

Prolactin has been shown to be active as an immunomodulatory hormone and is therefore of potential importance in disease progression and development. Any polymorphism in the gene and regulatory sequences may prove useful for disease association studies. A BglII polymorphism has been previously detected within the prolactin gene region. We have mapped this polymorphism to intron C and detected the base mutation that causes it. We have also developed a PCR‐RFLP method to genotype individuals.
Definition of new alleles of MIC‐A using sequencing‐based typing
Authors: Yao Z. , Volgger A. , Helmberg W. , Keller E. , Fan L. A. , Chandanayingyong D. , Albert E. D.
Published: March 2003

We have sequenced exons 2, 3 and 4 of MIC‐A in 23 homozygous cell lines, 22 families and 54 unrelated individuals. This has led to the definition of seven polymorphic positions in exon 2, 13 in exon 3 and 12 in exon 4, yielding a total of 33 different MIC‐A allelic specificities, of which 16 have not been described before. The newly defined sequences and those of the alleles defined before were entered into a database of the SCORE program (Helmberget al., 1998,Tissue Antigens,51, 587) for comprehensive genotyping analysis. In the tested sample, only one genotype present in two individuals gave rise to an ambiguous genotype. If all possible combinations of the 33 alleles are considered, 10 of 636 combinations are ambiguous. The MIC‐A exon 2, 3 and 4 polymorphism is characterized by diallelic single base exchanges and by a considerable degree of exon shuffling. The majority of heterozygote positions identified are non‐synonymous, i.e. five of seven in exon 2, 13 of 13 in exon 3 and eight of 12 in exon 4, suggesting an important function for the MIC‐A polymorphism.
Confirmation of a recombinant allele B*5603 and a hypothetical reciprocal hybrid
Authors: Lyou J.‐Y. , Yang K. L. , Lee A. , Lin P. Y. , Lee T. D.
Published: March 2003

From its DNA sequence, B*5603 is thought to be a product of gene conversion. We present here serological evidence of such an event and further speculate on a possible reciprocal hybrid yet to be identified. In addition, we report the allelic frequency of B*5603 in the Taiwanese population and its association with A*1101, Cw*01 and DRB1*1201.
The CTLA4 +49 A/G dimorphism is not associated with type 1 diabetes in Czech children
Authors: Cinek O. , Dřevínek P. , Šumník Z. , Bendlová B. , Koloušková S. , Šnajderová M. , Vavřinec J.
Published: March 2003

We investigated the association of the CTLA4 +49 A/G dimorphism with type 1 diabetes in Czech children. Genotyping of 305 diabetic children and 289 controls by a novel PCR‐ARMS assay revealed no significant differences in the genotypic or allelic frequencies. This may be another piece of evidence against the +49 A/G transition as the aetiological polymorphism within the CTLA4 gene.
A recently described polymorphism in the CD28 gene on chromosome 2q33 is not associated with susceptibility to type 1 diabetes
Authors: Wood J. P. , Pani M. A. , Bieda K. , Meyer G. , Usadel K.‐H. , Badenhoop K.
Published: March 2003

Type 1 diabetes mellitus is an autoimmune disease with a strong genetic background. The CTLA4 gene region (IDDM12) has been implicated in genetic susceptibility to type 1 diabetes by genome scanning and both family‐ and population‐based analyses. As the genes encoding the costimulatory molecules CTLA4 and CD28, which compete for the receptor B7, reside close together on chromosome 2q33 and have high sequence homology, we investigated a recently described polymorphism in intron 3 of the CD28 gene and the CLTA4 codon 17 polymorphism in 176 patients with type 1 diabetes and 220 healthy controls. Whereas CTLA4 was found to be associated with type 1 diabetes, the frequency of the CD28 polymorphism did not differ between patients and controls, either in the entire sample or after stratification for CTLA4 genotype. Thus, the CD28 intron 3 polymorphism does not appear to be associated with susceptibility to type 1 diabetes.
Polymorphism in codons 10 and 25 of the transforming growth factor‐beta 1 (TGF‐β1) gene in patients with invasive squamous cell carcinoma of the uterine cervix
Authors: Stanczuk G. A. , Tswana S. A. , Bergstrom S. , Sibanda E. N.
Published: March 2003

Transforming growth factor‐beta 1 (TGF‐β1) has a multifactorial role in the development of cervical cancer. It potently inhibits the growth of epithelial cells that harbour oncogenic human papilloma viruses (HPVs). TGF‐β1 also inhibits the expression of the early viral transforming regions E6 and E7, which appear to be the key oncoproteins. It has been suggested that squamous cell carcinomas are devoid of TGF‐β1, raising the possibility that elevated levels of this growth factor could protect against cervical cancer. It is also recognized that the production and levels of TGF‐β1 are genetically predetermined and individually variable. Two genetic polymorphisms in the DNA encoding the leader sequence of the TGF‐β1 gene have been described and shown to be associated with the production of high or low TGF‐β1 levels in vivo and in vitro. We hypothesized that the inheritance of these polymorphisms could influence the development of invasive cervical cancer. This hypothesis was investigated by studying polymorphism in codons 10 and 25 of the TGF‐β1 gene. We studied 97 patients with invasive cervical cancer and 73 healthy controls and found that the distributions of alleles T (Leu) and/or C (Pro) and alleles G (Arg) and/or C (Pro) in codons 10 and 25, respectively, were similar. There was no significant association between the alleles and the histological degree of cancer differentiation. It appears that the role of this growth factor in cervical oncogenesis is not related to the point mutations that we examined in codons 10 and 25 of the TGF‐β1 gene. We speculate that other factors, including additional polymorphisms of the TGF‐β1 gene, the status of TGF‐β1 receptors, the complex cytokine network, differential responsiveness of cells to the stimuli, and the status of the precancer/cancer genome, may play a role in development of invasive cervical cancer.
Further support for the association of CCR5 allelic variants with asthma susceptibility
Authors: McGinnis R. , Child F. , Clayton S. , Davies S. , Lenney W. , Illig T. , Wjst M. , Spurr N. , Debouck C. , Hajeer A. H. , Ollier W. E. R. , Strange R. , Fryer A. A.
Published: March 2003

English and German nuclear families containing multiple asthmatic children and asthmatic parents were analysed to retest a recently reported association between resistance to asthma and the Δ32 allele of chemokine receptor 5 (CCR5). Analysis of the families by the transmission‐disequilibrium test (TDT) revealed a non‐significant trend in the English families that provided marginal confirmation of the association (P < 0.125), but no similar trend was observed in the German families. Case–control comparison of Δ32 allele and genotype frequencies in asthmatic vs. non‐asthmatic parents revealed a significantly lower frequency of Δ32 in asthmatic English parents (P < 0.009) and a similar but non‐significant trend in German parents (P < 0.265). Taken together, the pattern of results provides confirmation for the previously observed Δ32–asthma association and indicates that susceptibility to asthma may be influenced by CCR5 or another gene in chromosomal region 3p21.
Soil friability: theory, measurement and the effects of management and organic carbon content
Authors: Watts C. W. , Dexter A. R.
Published: March 2003

The weakest link between particles or aggregates determines the strength of soil. We have re‐examined the theory and, as a result, have re‐defined friability, F, as the coefficient of variation of soil tensile strength. The formal relationship between the parameter 1/α of the weakest link theory of strength, which has previously been used as a measure of friability, and the newly defined measure, F, is described by a simple equation which has an accuracy of within 2% over the range of interest. The quantity F is used to show that friability reaches maximum at water contents around the lower plastic limit, that mechanical disturbance of wet soil by tillage reduces the friability, and that friability is strongly positively correlated with the organic carbon content of the soil. These results show the merit of measuring friability for determining the optimum water content for tillage, for quantifying the damage done by different tillage practices, and as a theoretically based index of soil physical quality.
Nematode (Caenorhabditis elegans) movement in sand as affected by particle size, moisture and the presence of bacteria (Escherichia coli)
Authors: YOUNG  , GRIFFITHS  , ROBERTSON  , McNICOL
Published: March 2003

The movement of bacterial‐feeding nematodes (Caenorhabditis elegans) through sand was investigated using a range of sand sizes, equilibrated at a range of matric potentials, in the presence or absence of an attractant source (Escherichiacoli) at the distal end of a column. In the presence of E. coli there was significantly greater movement of the nematode population towards the E. coli population, and the extent of the movement depended on the matric potential of the sand. Over time, an increasing proportion of the C. elegans population responded to the presence of the E. coli. The processes controlling these effects are discussed with respect to taxis and kinesis mechanisms of the nematode population, and with regard to the diffusive characteristics of the physical structure of the sand.
Transfer of dissolved Al, Fe and Si in two Amazonian forest environments in Brazil
Authors: CORNU S. , LUCAS Y. , AMBROSI J. P. , DESJARDINS T.
Published: March 2003

The balance of Si, Fe and Al in the soil solution determines more or less the course of soil formation in the tropics. We have tried to improve understanding of the processes by studying fluxes of dissolved Si, Fe and Al from the atmosphere, through the canopy and the soil, and to the groundwater, in two distinct Amazonian ecosystems, one a typical rainforest, developed on a Ferralsol, the other a so‐called ‘Campinarana’ forest, developed on a Podzol. The Si, Fe and Al in the rain and the throughfall and the stemflow were measured throughout a year, and the leaching of Si, Fe and Al through the upper soil and at the groundwater level were estimated. The annual balance showed that stemflow inputs were negigible compared with the contributions from throughfall and rain. The inputs of Fe, Al and Si to the topsoil from the rain and from dust and biological release in the canopy were small but not negligible. These sources contributed more aluminium in the Campinarana than in the rainforest. The rainfall constituted the main input of dissolved Fe and Al to the topsoil in both ecosystems. The element balances in the soil horizons confirmed that the present functioning of the Ferralsol results in aluminization and desilicification. We also found that the elements are transported in micropore flow and on translocated particles, as well as in freely percolating water.
The loess soils of China as records of climatic change
Authors: KEMP R. A. , DERBYSHIRE E.
Published: March 2003

The sequence of palaeosols and intervening loess units in North China provides a sensitive, detailed record of global climatic changes over the last 2.5 million years. Although various depth functions of properties, notably magnetic susceptibility, have been successfully correlated with oxygen isotope records from the deep oceans, there is a need to improve our understanding of such proxy measures used to infer past climates. For instance, pedologists are well placed to address some of the uncertainties surrounding the origin of the enhanced magnetic susceptibility (MS) values in palaeosols, and the reconstruction of palaeoprecipitation patterns by application of MS climofunctions. There are few published field descriptions of the soils buried in the loess, and those available often fail to recognize their accretionary and polycyclic nature. Field and micromorphological techniques enable finely detailed reconstructions of the pedogenic and sedimentary signals held in both palaeosol and loess units. Micromorphology, in particular, has provided detailed environmental information on successive pedosedimentary developmental stages at several sites in the Loess Plateau of China. This approach re‐focuses attention on the local, climatically sensitive mechanisms that underpin the inferred global patterns of climate.
Ilmenite in soil forming from a Brazilian amphibolite
Authors: DORIGUETTO A. C. , GOULART A. T. , DE JESUS FILHO M. F. , FABRIS J. D. , SANTANA G. P.
Published: March 2003

Ilmenite‐rich samples were obtained by chemical extraction methods from materials collected from a soil developing on an amphibolite and from its altered parent rock. The soil ilmenite of this mantle was found to be inherited from the rock, but its composition varied significantly from one soil fraction to another and according to its mineralogical association. Unit cell parameters are smaller than those of pure ilmenite: the a‐dimension of the hexagonal structure varies from 0.5076 ± 0.0004 to 0.5083 ± 0.0007 nm. Mössbauer patterns at room temperature reveal that this mineral, which is most often associated with the iron‐rich spinel phase, actually corresponds to a member of the haematite–ilmenite series having the general formula xFeTiO3.(1‐x)Fe2O3, with 0.83 ≤x≤ 0.95. There is a correlation (r= 0.95) between x, the molar fraction of FeTiO3, and the a‐dimension of the unit cell.
Interaction between clay microstructure, decomposition of plant residues and humification
Authors: D'ACQUI L. P. , DANIELE E. , FORNASIER F. , RADAELLI L. , RISTORI G. G.
Published: March 2003

We have studied microstructural changes in montmorillonite and kaolinite, which were amended with organic debris (leaves of chestnut or beech), microbial inoculum and nutrients and subjected, for 30 days at 25°C, to alternate drying and wetting (D–W) or kept continuously moist at water‐holding capacity (WHC). The objective was to evalute the interactions between the decomposition of plant residues and clay microstructural organization in different pore–water regimes. The microstructure was studied by Hg porosimetry, N adsorption at 77 K, and scanning electron microscopy. Decomposition was assessed by measuring residual C and N, the amount of humified material, the relative contents of humic (HA) and fulvic (FA) acids, and their molecular weight distribution. The structural organization at the end of the experiments was different for the two clays, and new classes of pores were found as the result of the microbial metabolism. The decomposition was also significantly affected by clay type. Decomposition of the organic matter (OM) was rapid in the montmorillonite. The humified material occured mainly as low molecular weight FAs. By contrast, transformation was slow in kaolinite, leaving much residual C, and more of the humified material consisted of HAs. Alternate D–W had little effect on microstructure and decomposition. Samples that were kept moist and amended with chestnut leaves produced the greatest amount of humified substances. The dynamics of the decomposition was significantly affected by the nature of the leaves as indicated by the differences in residual C, humified material and C/N ratio. By contrast, changes in pore size distribution (PSD) were litle influenced by the type of organic debris.
Soil moisture monitoring at the field scale using automatic capacitance probes
Authors: CHANZY A. , CHADOEUF J. , GAUDU J. C. , MOHRATH D. , RICHARD G. , BRUCKLER L.
Published: March 2003

The capacitance probe is an attractive device for monitoring soil moisture automatically. However, its sphere of influence is rather small (a few cubic centimetres only). We have analysed the possibility of monitoring moisture at the field scale using only a few probes (≤3). We calibrated each probe by establishing a direct relation between the field average soil moisture θf and the signal given by the probe. As in earlier studies, we found that a linear relation is generally suitable. A classical statistical analysis was performed to assess the error of a single probe. When replicate probes were installed, we obtained replicate estimates of θf. We proposed an estimator θf that combines all replications optimally.

Three experiments each lasting several months were carried out on bare tilled fields to evaluate the probe against gravimetric measurements. Our results show that the calibrations differ significantly from one probe to another. Once calibrated, the capacitance probe provided accurate soil moisture measurements (70% of the calibration relations had residual standard deviations < 0.02m3m−3), but it is advisable to have at least two replicate probes. Soil water storage was well estimated by combining four to seven probes to establish the moisture profile, despite the error induced by each probe. Moreover, the temporal variations in water storage were accurately measured by the probes. We found an error of 0.6 mm day−1 (standard deviation) in daily variation of the water storage, which partly involved the error made on the reference measurements (gravimetric method).
The effect of maize straw placement on mineralization of C and N in soil particle size fractions
Authors: Stemmer M. , Von Lützow M. , Kandeler E. , Pichlmayer F. , Gerzabek M. H.
Published: March 2003

Fundamental knowledge about the complex processes during the decomposition, mineralization and transfer of residue organic matter in soils is essential to assess risks of changes in agricultural practices. In a double tracer (13C, 15N) experiment the effect of maize straw on the mineralization dynamics and on the distribution of maize‐derived organic matter within particle size fractions was investigated. Maize straw (a C4 plant) labelled with 15N was added to soils (13.2 g dry matter kg–1 soil) which previously had grown only C3 plants, establishing two treatments: (i) soil mixed with maize straw (mixed), and (ii) soil with maize straw applied on the surface (surface). Samples were incubated in the laboratory at 14°C for 365 days. The size fractions (> 200 μm, 200–63 μm, 63–2 μm, 2–0.1 μm and < 0.1 μm), obtained after low‐energy sonication (0.2 kJ g–1), were separated by a combination of wet‐sieving and centrifuging. The mineralization of maize C was similar in the two treatments after one year. However, decomposition of maize particulate organic matter (predominantly in the fraction > 200 μm) was significantly greater in the mixed treatment, and more C derived from the maize was associated with silt‐ and clay‐sized particles. A two‐component model fitted to the data yielded a rapidly mineralizable C pool (about 20% of total C) and a slowly mineralizable pool (about 80%). Generally, the size of the rapidly mineralizable C pool was rather small because inorganic N was rapidly immobilized after the addition of maize. However, the different mean half‐lives of the C pools (rapidly decomposable mixed 0.035 years, and surface‐applied 0.085 years; slowly decomposable mixed 0.96 years, and surface‐applied 1.7 years) showed that mineralization was delayed when the straw was left on the surface. This seems to be because there is little contact between the soil microflora and plant residues. Evidently, the organic matter is more decomposed and protected within soil inorganic compounds when mixed into the soil than when applied on the soil surface, despite similar rates of mineralization.
Functional analysis of soil organic matter as affected by long‐term manurial treatment
Authors: Ellerbrock R. H. , Höhn A. , Rogasik J.
Published: March 2003

The composition of soil organic matter (SOM) is influenced by land use and fertilization. We studied changes in the SOM in a long‐term field experiment on a sandy Podzoluvisol. The control plot and four combinations of manurial treatments of the experiment were selected: one with mineral fertilizer only and three combinations of organic manure with mineral fertilizer: cattle manure + NPK, cattle manure + PK and straw + NPK. The SOM was extracted by sodium pyrophosphate solution (pH = 10) and hot water (100°C). The extracts were analysed by Fourier‐Transform Infrared (FT‐IR) spectroscopy and gel permeation chromatography (GPC). The FT‐IR spectra from sodium pyrophosphate extracts indicate that composition of SOM is indeed influenced by different fertilization. The C=O band at 1710 cm–1 in the samples of the plots fertilized with cattle manure has the highest absorption intensity, whereas the material from the plot fertilized with straw + NPK has the least intense. The GPC analyses of the extracts showed that adding cattle manure + NPK increased the molecular size of SOM in comparison with the control plot. The analysis of hot‐water extracts with FT‐IR showed no significant differences in functional groups, but GPC chromatograms distinguished features in molecular size distribution. Fertilization with cattle manure increased the molecular size of the SOM in comparison with the control, but the differences in content of carboxylic groups and molecular weight were detected in sodium pyrophosphate extracts only.
Evaluation of an ultrasonic dispersion procedure to isolate primary organomineral complexes from soils
Authors: Schmidt M. W. I. , Rumpel C. , Kögel‐Knabner I.
Published: March 2003

Soil organic matter can be intimately associated with mineral particles of various sizes. For structural studies, soil organic matter can be isolated in particle size fractions after complete dispersion of the aggregates by ultrasonication. The ultrasonic dispersion energy necessary for complete dispersion was investigated in three A and two B horizons originating from four soils differing in pedogenesis (Gleysol, Phaeozem, Podzol, Alisol), organic C (4.2–34.5 g kg–1) and clay content (24–294 g kg–1). Calorimetric calibration of five probe‐type ultrasonifiers revealed that the actual energy output from an instrument can depart widely from its nominal output, and that this discrepancy varies from instrument to instrument. Calorimetric calibration is therefore essential for consistency and comparisons between laboratories. Between 450 and 500 J ml–1 of ultrasonic dispersion energy was enough to disperse completely all samples investigated. The particle size distributions obtained were close to those from standard analysis, except for smaller yields (–20 to –80 g kg–1) of sand size fractions, which suggests that dispersion by ultrasound is more effective. Based on total C, C:N ratio and distribution of dissolved C, no detachment of soil organic matter from primary organomineral complexes and no redistribution between particle size fractions could be detected in the range 30–590 J ml–1 of dispersion energy.
n‐Alkanes and free fatty acids in humus and A1 horizons of soils under beech, spruce and grass in the Massif‐Central (Mont‐Lozère), France
Authors: Marseille F. , Disnar J. R. , Guillet B. , Noack Y.
Published: March 2003

Soil profiles under beech, spruce and a grassland have been analysed to study the evolution of natural n‐alkanes in pollution‐free ecosystems. The soils had all developed on granitic bedrock, at an altitude of 1300–1500 m in the region of Mont‐Lozère (southern Massif‐Central, France). In contrast to the grassland soil, the two forest soils both possessed a well‐developed acidic moder humus‐type horizon. This could be subdivided as follows: fresh litter (OL), fragmentation (OF) and humification (OH) layers; two litters, one fresh (OL1) and one old (OL2) could actually be distinguished in the beech forest soil. The n‐alkane signature of the parent plants was preserved in the top litter. Immediately underneath, in the OF layer(s) the original n‐alkane signatures were progressively but rapidly replaced by a common signature composed of n‐C27 and n‐C25 with larger proportions of the former than of the latter. These two hydrocarbons were most probably produced in situ by fungi. These results appear to illustrate the action of soil microorganisms which metabolize the inherited n‐alkanes and produce new compounds of the same family. Unlike the alkanes and the low molecular weight fatty acids ≤ C20 (which increase greatly in the OL2 layer under beech as a result of intense microbial activity), the heavy fatty acids (> C20) show no significant change in the organic horizon.