bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcapillary insulin transfer in human skeletal muscle
Authors: Herkner H. , Klein N. , Joukhadar C. , Lackner E. , Langenberger H. , Frossard M. , Bieglmayer C. , Wagner O. , Roden M. , Müller M. 
Published: March 2003

AbstractBackground Transcapillary insulin transfer is considered a rate‐limiting step in insulin action at supraphysiological insulin concentrations. However, it remains unclear whether this concept also applies for physiological conditions.Materials and methods In the present study we set out to characterize transcapillary insulin transfer by measuring insulin concentrations in plasma and interstitial space fluid of skeletal muscle during an oral glucose tolerance test and euglycaemic hyperinsulinaemic clamp conditions, respectively. For this purpose we employed in vivo microdialysis of skeletal muscle in conjunction with an ultrasensitive insulin assay in eight healthy lean male volunteers (aged 25 ± 1 years).Results Insulin concentrations at baseline were 48 ± 8 pmol L−1 in plasma and 19 ± 4 pmol L−1 in the interstitium (P = 0·002). The mean interstitium to plasma ratio at baseline was 0·48 ± 0·09 pmol L−1. During the oral glucose tolerance test the interstitium to plasma ratio remained unchanged (0·43 ± 0·12, P = NS vs. baseline), but was significantly reduced during euglycaemic hyperinsulinaemic clamp conditions at steady‐state hyperinsulinaemia (0·12 ± 0·01, P = 0·01 vs. baseline).Conclusion In summary there is a substantial transcapillary insulin gradient in healthy human skeletal muscle under baseline and glucose‐stimulated conditions. Our findings support the hypothesis of a saturable transcapillary insulin transport representing a partly rate‐limiting step for insulin action.
The evolution of β‐cell dysfunction and insulin resistance in type 2 diabetes
Authors: Bergman R. N. , Finegood D. T. , Kahn S. E. 
Published: March 2003

AbstractInsulin resistance and β‐cell dysfunction have important roles in the pathogenesis and evolution of type 2 diabetes. The development of precise methods to measure these factors has helped us to define the relationship between them and evidence is reviewed that changes in insulin sensitivity are compensated by inverse changes in β‐cell responsiveness such that the product of insulin sensitivity and insulin secretion (the disposition index) remains constant. While the disposition index promises to be a useful tool to predict individuals at high risk of developing type 2 diabetes, other factors that contribute to β‐cell dysfunction and mark disease onset and progression include impairments in proinsulin processing and insulin secretion, decreased β‐cell mass and islet amyloid deposition. Emerging data indicate that anti‐diabetic agents, such as the thiazolidinediones that simultaneously target insulin resistance and β‐cell dysfunction, may have a beneficial impact on disease onset and progression. Several landmark clinical studies are underway to investigate if their initial promise is supported by data from large‐scale trials.
Mitochondrial DNA polymorphism in the Vietnamese population
Authors: Ivanova R. , Astrinidis A. , Lepage V. , Djoulah S. , Wijnen E. , Vu‐Trieu A. N. , Hors J. , Charron D. 
Published: March 2003

AbstractThe mitochondrial DNA variation was screened in a sample of 50 unrelated individuals of the Vietnamese population originating from Hanoi. A combination of long and standard PCR and restriction endonuclease digests with the enzymes HpaI, BamHI, HaeII, MspI, AvaII and HincII were used to reveal mtDNA variation. Twenty enzyme morphs were detected, three of which (HaeII‐13Viet, MspI‐19Viet and MspI‐20Viet) are new and are produced by a single mutational event in already known enzyme morphs. Ten already known and four new mitotypes [93Viet (1‐1‐2‐4‐1), 94Viet (2‐1‐13Viet‐1‐1), 95Viet (2‐1‐13Viet‐19Viet‐1) and 96Viet (1‐1‐2–20Viet‐12)] were found in the Vietnamese population. The 9‐bp deletion occurring in the COII/tRNALys region of the mitochondrial genome was also analysed and 10 samples were found to have this deletion. The comparison of the Vietnamese with other East Asian populations showed a close genetic relationship of the population under investigation with other Orientals. However, the Vietnamese population can be differentiated by the significantly higher frequency of the enzyme morph HincII‐5 and by seven new markers. These results strongly support the hypothesis of a dual ethnic origin of the Vietnamese population from the Chinese and Thai–Indonesian populations based on HLA markers and linguistic evidence.
Common polymorphisms in the CTLA‐4 and CD28 genes at 2q33 are not associated with asthma or atopy
Authors: Heinzmann A. , Plesnar C. , Kuehr J. , Forster J. , Deichmann K. A. 
Published: March 2003

AbstractRecently, genetic linkage of the chromosomal region 2q33 with asthma has been shown. The genes coding for CD28 and CTLA‐4 have been localized to this chromosomal region. CD28 and CTLA‐4 have been shown to be involved as an important costimulatory signal in the regulation of allergic inflammation and TH2 cytokine production, and thus both genes are good candidate genes for asthma and atopy.Two common polymorphisms in the CTLA‐4 gene and one polymorphism in the CD28 gene found by single‐strand conformation polymorphisms (SSCP) analysis and direct genomic sequencing were tested for association with asthma and atopy phenotypes in a population of 260 largely atopic children and young adults. No association was found between any of the three polymorphisms and asthma or atopy phenotypes. The newly described common CD28 polymorphism is situated in the third intron of the gene. We conclude that neither gene is likely to exert a major influence on the development of asthma or atopy in our population. However, it might prove useful to test for association of these polymorphisms with asthma in populations recruited through asthmatic but not necessarily atopic individuals.
A study of Gm allotypes and immunoglobulin heavy gamma IGHG genes in Berbers, Arabs and sub‐Saharan Africans from Jerba Island, Tunisia
Authors: Yacoubi Loveslati B. , Sanchez‐Mazas A. , Ennafaa H. , Marrakchi R. , Dugoujon J.‐M. , Lefranc M.‐P. , Ben Ammar Elgaaied A. 
Published: March 2003

SummaryThe Gm polymorphism of human IgG immunoglobulins was investigated in three different ethnic groups — Arabs, Berbers and ‘dark‐skinned people’— on Jerba Island, Tunisia. The genetic relationships among these groups and several populations from North Africa, sub‐Saharan Africa, west Asia and Europe were analysed by principal coordinate analysis, Fst significance testing, and analysis of molecular variance based on haplotype frequencies. The results revealed a non‐significant genetic differentiation between Arabs and Berbers from Jerba. However, the Jerbian population of sub‐Saharan African origin was close to Ethiopians. Gene flow among the three Jerbian populations, as well as an East African origin of the dark‐skinned individuals, is proposed to account for the observed genetic pattern. However, the genetic diversity observed among the different Tunisian populations did not show any significant correlation with either geographic or linguistic differentiation. A preliminary analysis of the restriction fragment length polymorphism of the IGHG genes in Arabs and Berbers from Jerba confirmed the close genetic relationship between the two populations. However, it also indicated a lower level of genetic diversity in the Berbers, which may be explained by more rapid genetic drift due to longer isolation on the island.
HLA DMA and DMB show no association with rheumatoid arthritis in US Caucasians
Authors: Moxley G. , Han J. 
Published: March 2003

SummaryHLA DM is a heterodimeric molecule functioning in normal antigen presentation; it is encoded by adjacent HLA‐region loci, HLA DMA and DMB, located between DP and DQ. Some previous studies have suggested that HLA susceptibility to rheumatoid arthritis (RA) is associated with certain DMA and DMB alleles. Our aim was to examine whether this association is also present in US Caucasians. We studied 288 US Caucasian subjects with rheumatoid arthritis and 263 US Caucasian control subjects. DMA and DMB typing was achieved by PCR amplification followed by sequence‐specific oligonucleotide hybridization and by PCR–restriction fragment length polymorphism. There was no frequency difference for DMA alleles or DMB alleles between RA and control subjects, indicating no association. Neither was a difference apparent when data were analysed in subgroups based on shared‐epitope DRB1, on the rheumatoid factor test, on radiographic changes of RA, or on sex. DRB1‐DQB1‐DMB analyses for linkage disequilibrium showed that the DRB1*0401‐DQB1*0301 haplotype had the DMB*0103 allele more often than DMB*0101 (estimated haplotype frequencies 0.08 and 0.039 in RA, respectively). In contrast, the DRB1*0401‐DQB1*0302 haplotype usually had the DMB*0101 allele (haplotype frequency 0.084 compared to 0.01 for DMB*0103). Thus, neither HLA DMA nor DMB was associated with RA in this population, and not all shared‐epitope‐bearing haplotypes had the same DMB allele distribution.
Prevalence of human leukocyte antigen (HLA) DRB1 alleles in Kuwaiti children with juvenile rheumatoid arthritis
Authors: Alsaeid K. , Haider M. Z. , Kamal H. , Srivastva B. S. , Ayoub E. M. 
Published: March 2003

SummaryThe prevalence of human leukocyte antigen (HLA) DR alleles has been determined in 69 Kuwaiti Arab children with juvenile rheumatoid arthritis (JRA) and compared to that in 212 ethnically matched normal healthy controls using a PCR–sequence specific primers (PCR‐SSP) method. A very high incidence of DR3 was detected in JRA patients compared to the controls (P < 0.0001, RR = 2.235). The high incidence of HLA‐DR3 in JRA patients was accounted for mainly by an excess of DRB1*0307 (P < 0.05, RR = 3.072) and DRB1*0308 (P < 0.009, RR = 2.663) compared to the controls. Moreover, DR3 was more prevalent when patients with ANA‐positive JRA were analysed separately; 73% compared to 58% for the whole JRA patient group. The frequency of DR1 was also higher in the JRA group compared to controls (P = 0.019, RR = 3.585). Although the incidence of some alleles was higher in the control group (DR13 and DR7), none reached a statistically significant level. All the patients with iridocyclitis had either a DR1 or DR3 allele, except for one child. The frequency of DRB1*03 was found to be much higher in the polyarticular subtype of Kuwaiti JRA cases compared to the oligoarticular subgroup and the controls. Also, a non‐significant increase in the frequency of the DRB1*04, *11 and *15 alleles was detected in the polyarticular subtype of the Kuwaiti JRA cases compared to the controls.
CD45 exon 4 point mutation does not confer susceptibility to type 1 diabetes mellitus or Graves’ disease
Authors: Wood J. P. , Bieda K. , Segni M. , Herwig J. , Krause M. , Usadel K. H. , Badenhoop K. 
Published: March 2003

SummaryA point mutation in the leukocyte common antigen (CD45, C → G77, exon 4) was investigated in patients with type 1 diabetes (IDDM), patients with Graves’ disease and controls. The distribution did not differ significantly between patients and controls. This CD45 variant does not therefore confer susceptibility to either IDDM or Graves’ disease.
A BAC contig of approximately 400 kb contains the classical class I major histocompatibility complex (MHC) genes of cattle
Authors: Di Palma F. , Archibald S. D. , Young J. R. , Ellis S. A. 
Published: March 2003

SummaryA cattle BAC library derived from an MHC homozygous animal was screened for MHC class I genes. This revealed at least nine class I‐related genes in a contig spanning ~400 kb, and several additional genes on other clones. The three classical class I genes expressed on this haplotype (A14) were shown to be distributed over a region at most 212 kb apart.
HLA class I polymorphism in a Moroccan population from Casablanca
Authors: Choukri F. , Chakib A. , Himmich H. , Raissi H. , Caillat‐Zucman S. 
Published: March 2003

SummaryWe have studied the distribution of HLA‐A and ‐B alleles and haplotypes by sequence‐specific primer amplification in a sample of 100 unrelated healthy individuals belonging to both Berber and Arabic‐speaking groups from the region of Casablanca in Morocco. Among the 17 HLA‐A and 23 HLA‐B alleles observed, the most frequent were HLA‐A2 (21%), ‐A1 (11%), ‐A3 (10%), ‐B44 (11.4%), ‐B50 (9.9%), ‐B5(8.5%) and ‐B35 (6.5%). Six two‐locus haplotypes were observed with a frequency above 5%: A2‐B50 (9.6%), A23‐B44 (7.4%), A2‐B15 (6.4%), A68‐B39 (5.3%), A1‐B51 (5.3%) and A68‐B44 (4.3%). Our data confirm that, on the basis of genetic distances, the majority of present‐day North Africans from Morocco are closely related to Berbers and also to Iberians. They cluster apart from Middle‐Eastern Mediterranean populations, and show greater genetic distances to Eastern and other Mediterranean populations. This study will serve as a reference for further anthropological studies, as well as studies of HLA and disease associations.
HLA‐DPB1 allelic frequency of the Pumi ethnic group in south‐west China and evolutionary relationship of Pumi with other populations
Authors: Liu Z.‐H. , Lin J. , Pan D. , Chen W. , Tao H. , Xu A. 
Published: March 2003

SummaryA sequencing‐based typing of the HLA‐DPB1 gene was carried out in 51 unrelated healthy individuals from the Yunnan Pumi ethnic minority. A total of 18 DPB1 alleles, in which DPB1*0501 (52.0%) and DPB1*0402 (15.7%) greatly predominated, were found, of which alleles DPB1*20011, 2201, 3601, 3701, 3801, 4901, 5001 and 8001 were recorded for the first time in the Chinese population. This may be because the typing methods used in previous genotyping of Chinese populations were of lower sensitivity than that used in our study. A dendrogram constructed by the maximum likelihood method showed that the Pumi ethnic minority belongs to the Asian/Australasian cluster and has the closest relationship to Trobriander, implying an unusual relationship between Australasian and South China populations. However, the Yi ethnic minority, which also comes from the ancient Qiang, did not show a very close relationship with the Pumi. This is probably because the Pumi were historically assimilated by local south‐west China populations.
Nucleotide sequence of the upstream regulatory region of BoLA–DRB†
Authors: Ripoli M. V. , Díaz S. , Peral‐García P. , Giovambattista G. 
Published: March 2003

SummaryThe sequence of the proximal upstream regulatory region (URR) of the bovine DRB genes was amplified using oligonucleotide primers designed from the consensus among DRB sequences from different species. The obtained DNA sequence was 234 bp long and composed of highly conserved sequence motifs, showing the same organization as the HLA‐DRB, H2‐IAb, H2‐IEb and ELA‐DRB genes.
Steroid‐sensitive nephrotic syndrome and vascular endothelial growth factor gene polymorphisms
Authors: Holt R. C. L. , Ralph S. A. , Webb N. J. A. , Watson C. J. , Clark A. G. B. , Mathieson P. W. , Brenchley P. E. C. 
Published: March 2003

SummaryGenetic polymorphisms have been recognized as important determinants of gene expression. Three common single nucleotide polymorphisms have been identified in the promoter and 5′ untranslated region of the vascular endothelial growth factor (VEGF) gene: −460 C → T, −141 A → C and +405 G → C. As VEGF has been postulated to play a role in the pathogenesis of childhood steroid‐sensitive nephrotic syndrome (SSNS), this study tested the hypothesis that VEGF genotype may be associated with susceptibility to SSNS. We examined the genotype frequencies of these polymorphisms in a total of 116 children with SSNS and 150 control subjects, using polymerase chain reaction–restriction fragment length polymorphism analysis (PCR‐RFLP). There were no statistically significant differences in any of the genotype frequencies between SSNS patients and controls. We conclude that VEGF −460, −141 and +405 genotypes are not associated with susceptibility to childhood SSNS.
Genotyping for cytokine polymorphisms: allele frequencies in the Italian population
Authors: Uboldi de Capei M. , Dametto E. , Fasano M. E. , Rendine S. , Curtoni E. S. 
Published: March 2003

SummaryIt has been demonstrated that many cytokine genes [e.g. tumour necrosis factor α (TNF‐α) and interleukin 10 (IL‐10)] show polymorphisms which may affect gene transcription, causing individual variations in cytokine production. The majority of polymorphisms described are single nucleotide polymorphisms (SNPs). In 140 healthy Italian subjects, the allelic and genotype frequencies were determined for the cytokine genes IL‐1α (T/C −889), IL‐1α (C/T −511, T/C +3962), IL‐12 (C/A −1188), interferon (IFN)‐γ (A/T UTR 5644), transforming growth factor (TGF)‐α (C/T codon 10, G/C codon 25), TNF‐α (G/A −308, G/A −238), IL‐2 (T/G −330, G/T +166), IL‐4 (T/G −1098, T/C −590, T/C −33), IL‐6 (G/C −174, G/A nt565), IL‐10 (G/A −1082, C/T −819, C/A −592), IL‐1R (C/T pst11970), IL‐1RA (T/C mspa111100) and IL‐4RA (G/A +1902). All typings were performed with PCR‐SSP assays. Allele and genotype frequencies and linkage disequilibria were calculated and compared with those of other populations.
Modelling the concentration or dilution of saline soil‐water systems
Authors: Rieu M. , Vaz R. , Cabrera F. , Moreno F. 
Published: March 2003

SummaryFor the survey of saline and alkali soils sampling soil solution in situ is difficult. An alternative is to take soil samples, analyse their extracts and then calculate the chemical composition of the soil solution. A model (EXPRESO) has been designed to calculate both the chemical speciation of electrolyte solution and the exchange equilibrium with an adsorbed phase during simulated dilution and concentration. EXPRESO was validated using reclaimed saline soil samples. Results demonstrated that EXPRESO is a thermodynamically coherent and mass conservative model that allows the calculation of the chemical composition of both the soil solution and the exchange complex over a large range of soil water content (0.250–5 kg water kg–1 soil). EXPRESO enables the estimation of the chemical composition of the in situ soil solution, giving a comprehensive picture of the soil status under different field conditions. Modélisation de la concentration ou de la dilution des systèmes eau‐sols salés Résumé
Transformations and neoformations of clay in the cryogenic environment: examples from Transbaikalia (Siberia) and Patagonia (Argentina)
Authors: VOGT T. , LARQUÉ P. 
Published: March 2003

SummaryPermafrost desiccates and indurates soil horizons. During summer, the perennially frozen ground under the active thawed layer creates confined conditions, Whereas in winter the closed system between the permafrost and the freezing front migrating downwards leads to irreversible changes in the soil structure and to transformation and neoformation of minerals. Two examples were studied by field observation and laboratory analyses (optical microscopy, scanning electron microscopy, X‐ray diffractometry, transmission electron microscopy and analytical electron microscopy). In Transbaikalia (southeastern Siberia) a Pleistocene cryogenic slope deposit on syenite contains detrital clays (chlorite, illite), but neoformed ferroan smectites dominate. In Patagonia, centimetre‐sized silica concretions containing spongy and spheroidal opal occur in alluvium ascribed to cold Pleistocene periods. They seem to have formed from primary detrital smectite that was transformed to fibrous clay (sepiolite) then to acicular opal, and eventually to spheroidal opal. The neoformed opal contains 27% magnesium. These features occur systematically within fossil cryoturbations not related to present conditions. It appears that clay transformation and neoformation can happen at temperatures far lower than 0°C.
Modelling cations in three acid soils with differing acid input in Germany
Authors: LUDWIG B. , PRENZEL J. , KHANNA P. K. 
Published: March 2003

SummaryPrediction of concentration changes of cations in soil solutions is complex, and chemical models are necessary for the purpose. The objective of this study was to determine whether the reactions considered in a coupled equilibrium model were appropriate to predict cation concentrations when the initial equilibrium was disturbed by adding small amounts of electrolytes. Multi‐ion sorption in three acid soils (two Cambisols and a Podzol) was studied by sequentially adding small amounts of electrolytes to samples of the soils in batch experiments. A chemical equilibrium model that included inorganic complexation and multiple cation exchange was used to interpret the results. For the subsoils, the solubility of jurbanite was also included in the model.Model results for the two Cambisol surface soils agreed well or satisfactorily with the measured pH and sorption values of Na, K, Mg, Ca, Mn, Al and Fe, with a few exceptions. Linear correlation coefficients were generally between 0.97 and 1, and the regressin coefficients for cations (modelled against measured) lay between 0.6 and 1.3. For the subsoils sorption of sulphate was described satisfactorily for the spodic dystric Cambisol and to some extent for the spodic Cambisol. Correlation coefficients for subsoils lay between 0.63 and 1, and the regression coefficients (modelled against measured) were between 0.9 and 1.6 for the Cambisols. The model did not predict pH and sorption data in surface and subsurface soils with very small amounts of exchange capacities, pointing to the significance of cation buffering resulting from exchange sites. This study showed the usefulness and limitations of equilibrium models to predict the composition of the soil solution.
Particle packing and organization of the textural porosity in clay–silt–sand mixtures
Authors: FIÈS J. C. , BRUAND A. 
Published: March 2003

SummaryThe packing of elementary particles in soil largely determines the properties that depend on the textural soil pore space, but is studied little. The relations between packing and size and nature of soil particles were studied using fractions of clay, silt and sand, mixed when wet and then dried. Ternary mixtures (clay:silt:sand) were compared with binary mixtures (clay:silt, clay:sand). The pore space of the mixtures was studied using mercury porosimetry and scanning electron microscopy. In all the mixtures the textural pore space was divided into two compartments: (1) lacunar pores due to the presence of skeleton particles and to the shrinkage of the clay phase between these particles, and (2) the clay–fabric pores due to the packing of the clay. In the ternary mixtures, lacunar pores could be divided into two classes: (1) those due to sand particles within the clay–slit phase considered as a single phase, and (2) those due to silt particles within this same phase. For certain mixtures, lacunar pores, referred to as hidden lacunar pores, were not interconnected but were occluded. This occurred both for hidden pores caused by the presence of sand and occluded by the clay–slit phase, and for hidden pores caused by the presence of silt and occluded by the clay phase. The relations between these types of textural pores and the proportions of different size fractions in the mixtures provide guidelines for making optimum use of the particle‐size characteristics of the soil to determine its properties.