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L Samuelsson

Publications and source records attributed to L Samuelsson.

At least 19 recordsLinked to original sources
PubMed2003

Decreasing levels of tumour necrosis factor alpha and interleukin 6 during lowering of body mass index with orlistat or placebo in obese subjects with cardiovascular risk factors.

AIM: Obesity is associated with increased levels of inflammatory mediators. The objective of this study was to evaluate changes in the leucocyte derived inflammatory mediators tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and the isoprostane 8-epi-prostaglandin (PG) F2alpha during BMI lowering with orlistat (Xenical(R), Roche) or placebo. METHODS: TNF-alpha, IL-6, and 8-epi PGF2alpha evaluated in 376 subjects aged 18-75 years with BMI 28-38 kg/m2 before and after 1 year of double-blind, randomized treatment with orlistat 120 mg or placebo three times daily. RESULTS: Weight reduction was associated with decreasing (p < 0.001) levels of TNF-alpha and IL-6 in both orlistat and placebo groups. After 12 months, TNF-alpha was lower (p < 0.05) in the orlistat compared with the placebo group. In the orlistat group, the change in TNF-alpha correlated with change in s-glucose (r = 0.22; p = 0.01), and the change in 8-epi-PGF2alpha correlated with changes in s-cholesterol (r = 0.27; p < 0.001) and s-LDL-cholesterol (r = 0.28; p < 0.001). CONCLUSION: Weight reduction was associated with decreasing levels of both TNF-alpha and IL-6. After 12 months of treatment, TNF-alpha levels were lower in orlistat than in placebo-treated subjects. Whether these results translate into reduced incidence of cardiovascular disease remains to be elucidated.

Adolescent↗
PubMed2002

Thermal quantitative sensory testing in lumbar disc herniation.

The most frequent clinical presentation of sciatica suggests injury of sensor root fibers alone. To evaluate whether thermal quantitative sensory testing (QST) is applicable in the study of sensory dysfunction in lumbosacral disc herniations, 36 men and 30 women with L4/5 or L5/S1 disc herniations underwent thermal QST of the L4, L5, and Si dermatomes. For both levels of disc herniation, there was a significant difference for all temperature modalities, i.e., cold, warmth and heat pain, between all dermatomes as well as between the side of the herniated disc and the corresponding asymptomatic side. However, the proportion of herniated discs classified correctly was only 48% in patients with disc herniations at the L4/5 level, while it was 71% at the L5/S1 level. We conclude that thermal QST measurements reflect and document sensory dysfunction in patients with lumbosacral disc herniation. The method offers a new means both to study the time course of a spontaneous recovery of sensory dysfunction and to evaluate the result of different treatment options. However, thermal QST seems to have the same poor predictive value for identifying the anatomic location of a herniated lumbar disc as conventional electrophysiologic methods.

Adult↗
PubMed2002

The IL12B gene does not confer susceptibility to coeliac disease.

Coeliac disease (CD) is a chronic inflammatory disorder where dietary gluten is not tolerated. In the lesion there are gluten reactive T cells predominantly secreting gamma-interferon. Both HLA and non-HLA genes contribute to CD susceptibility. Interleukin-12 (IL-12) regulates gamma-interferon production. The IL12B gene is located in a region (5q31.1-33.1) where there is evidence for linkage with CD. Allele 1 of an IL12B 3'UTR single-nucleotide polymorphism leads to increased expression of IL-12, and was recently implicated in susceptibility for type 1 diabetes (T1D). We found no evidence for association of allele 1 to CD by the transmission/disequilibrium test or case-control approach. No increased frequency was observed in patients belonging to families where the disease was linked to markers on chromosome 5q. Unlike T1D, allele 1 does not appear to confer susceptibility to CD.

Alleles↗
PubMed2001

Insulin can enhance GLUT4 gene expression in 3T3-F442A cells and this effect is mimicked by vanadate but counteracted by cAMP and high glucose--potential implications for insulin resistance.

UNLABELLED: It is well-established that high levels of cAMP or glucose can produce insulin resistance. The aim of this study was to characterize the interaction between these agents and insulin with respect to adipose tissue/muscle glucose transporter isoform (glucose transporter 4, GLUT4) gene regulation in cultured 3T3-F442A adipocytes and to further elucidate the GLUT4-related mechanisms in insulin resistance. Insulin (10(4) microU/ml) treatment for 16 h clearly increased GLUT4 mRNA level in cells cultured in medium containing 5.6 mM glucose but not in cells cultured in medium with high glucose (25 mM). 8-Bromo-cAMP (1 or 4 mM) or N(6)-monobutyryl cAMP, a hydrolyzable and a non-hydrolyzable cAMP analog, respectively, markedly decreased the GLUT4 mRNA level irrespective of glucose concentrations. In addition, these cAMP analogs also inhibited the upregulating effect of insulin on GLUT4 mRNA level. Interestingly, the tyrosine phosphatase inhibitor vanadate (1-50 microM) clearly increased GLUT4 mRNA level in a time- and concentration-dependent manner. Furthermore, cAMP-induced inhibition of the insulin effect was also prevented by vanadate. In parallel to the effects on GLUT4 gene expression, both insulin, vanadate and cAMP produced similar changes in cellular GLUT4 protein content and cAMP impaired the effect of insulin to stimulate (14)C-deoxyglucose uptake. In contrast, insulin, vanadate or cAMP did not alter insulin receptor (IR) mRNA or the cellular content of IR protein. IN CONCLUSION: (1) Both insulin and vanadate elicit a stimulating effect on GLUT4 gene expression in 3T3-F442A cells, but a prerequisite is that the surrounding glucose concentration is low. (2) Cyclic AMP impairs the insulin effect on GLUT4 gene expression, but this is prevented by vanadate, probably by enhancing the tyrosine phosphorylation of signalling peptides and/or transcription factors. (3) IR gene and protein expression is not altered by insulin, vanadate or cAMP in this cell type. (4) The changes in GLUT4 gene expression produced by cAMP or vanadate are accompanied by similar alterations in GLUT4 protein expression and glucose uptake, suggesting a role of GLUT4 gene expression for the long-term regulation of cellular insulin action on glucose transport.

3T3 Cells↗
PubMed2001

Genome-wide linkage analysis of Scandinavian affected sib-pairs supports presence of susceptibility loci for celiac disease on chromosomes 5 and 11.

Celiac disease (CD) is a common chronic inflammatory disorder of the small intestine with a multifactorial aetiology. HLA is a well-known risk factor, but other genetic factors also influence disease susceptibility. To identify the genes involved in this disorder, we performed a genome-wide scan on 106 well-defined Swedish and Norwegian families with at least two affected siblings. We investigated familial segregation of 398 microsatellite markers, and utilised non-parametric linkage analysis. The strongest linkage with disease was found to the HLA locus (6p) (P<0.000006). There were eight regions besides HLA with a point wise P value below 0.05. Among these eight regions were 11q and 5q, both of which have been suggested in several linkage studies of independent celiac disease families. We also performed a stratification analysis of families according to their HLA genotypes. This resulted in significant differences on chromosome 2q. These results indicate that 11q, 5q and possibly also 2q are true susceptibility regions in CD.

Adolescent↗
PubMed2000

Stronger association with HLA-Cw6 than with corneodesmosin (S-gene) polymorphisms in Swedish psoriasis patients.

Psoriasis vulgaris is strongly associated with certain human leukocyte antigens, especially in early onset. The purpose of this study was to study the HLA-Cw6 allele and its contribution to disease susceptibility in a set of 104 families with at least two affected siblings. A sequencing method was utilized to examine the two exons that build up the antigen binding site of the C locus receptor. DNA from patients homozygous for Cw6 based on haplotype information were sequenced. The results confirmed the identity of the Cw6 allele in affected individuals with the consensus sequence for Cw*0602. We screened the set of families for psoriasis patients homozygous for Cw6 and found 11 individuals with a mean age at onset of 16.1 years. The corresponding figure for the Cw6 heterozygotes was 18.45 years and for the Cw6-negatives 22.36 years. This is indicative of a gene dose effect. We performed a transmission disequilibrium test (TDT) on the Cw6 allele per se, used as a biallelic marker. The analysis resulted in a P-value of 5.3 x 10(-17) (t167/nt45). This greatly exceeds our previous results of a TDT in the region, including microsatellite markers and single nucleotide polymorphisms (SNPs) in the coding part of the S gene (corneodesmosin), which is a suggested candidate gene in the region. The maximum nonparametric linkage (NPL) value was also reached using HLA-C as a marker. We conclude that Cw6 is the allele which shows the highest degree of association with psoriasis in our set of families and we propose that it directly influences the age at onset of the disease rather than increasing the genetic load in accordance with a polygenic theory.

Alleles↗
PubMed2000

The CTLA4/CD28 gene region on chromosome 2q33 confers susceptibility to celiac disease in a way possibly distinct from that of type 1 diabetes and other chronic inflammatory disorders.

The effect of the gene region on chromosome 2q33 containing the CD28 and the cytotoxic T-lymphocyte associated (CTLA4) genes has been investigated in several diseases with chronic inflammatory nature. In addition to celiac disease (CD), type I diabetes, Grave's disease, rheumatoid arthritis and multiple sclerosis have all demonstrated associations to the A/G single nucleotide polymorphism (SNP) in exon 1, position +49 of the CTLA4 gene. The purpose of this study was to investigate this gene region in a genetically homogeneous population consisting of 107 Swedish and Norwegian families with CD using genetic association and linkage methods. We found a significant association with preferential transmission of the A-allele of the exon 1 +49 polymorphism by using the transmission disequilibrium test (TDT). Suggestive linkage of this region to CD was moreover demonstrated by non-parametric linkage (NPL) analysis giving a NPL-score of 2.1. These data strongly indicates that the CTLA4 region is a susceptibility region in CD. Interestingly, of the several chronic inflammatory diseases that exhibit associations to the CTLA4 +49 A/G dimorphism, CD appears to be the only disease associated to the A allele. This suggests that the +49 alleles of the CTLA4 gene are in linkage disequilibrium with two distinct disease predisposing alleles with separate effects. The peculiar association found in the gut disorder CD may possibly relate to the fact that the gastrointestinal immune system, in contrast to the rest of the immune system, aims to establish tolerance to foreign proteins.

Abatacept↗
PubMed2000

S gene (Corneodesmosin) diversity and its relationship to psoriasis; high content of cSNP in the HLA-linked S gene.

Psoriasis is a heterogeneous disease in which several reports suggest the presence of a susceptibility gene in or in the proximity of the human leukocyte antigen complex in chromosome 6p. There is an association between HLA-Cw6 and young onset of the disease. The S gene (corneodesmosin), located 160 kb telomeric of HLA-C, is a strong candidate for psoriasis due to its reportedly exclusive expression in differentiating keratinocytes. We have studied this gene in a large Swedish psoriasis population and we report a strikingly high degree of polymorphism in the coding parts of the gene, 1 every 100 base pairs. We used a stratified approach to compare the polymorphic variants in patients and controls. A single nucleotide polymorphism in the coding region leading to an amino acid exchange (Ser-->Phe) that differed significantly between patients and controls was identified (position 619). Owing to a high allele frequency in a larger control group, however, and an insignificant influence of the variant on the age at onset distribution curve based on a large psoriasis population, we could not confirm that this coding single nucleotide polymorphism was involved in disease etiology. We also examined the single nucleotide polymorphism in position 1243, recently proposed to have an influence on the pathogenesis of the disease. This polymorphism showed less association to the disease as compared with the single nucleotide polymorphism at positions 619 and 722. Such a high degree of variation present also in an HLA gene which is not involved in immune response indicates the difficulty involved in assessing the role of a specific allele in the pathogenesis of a complex disease in this region. A strong association effect due to linkage disequilibrium in an extended region in the HLA complex is also a complicating factor.

Alleles↗
PubMed1999

A genome-wide search for genes predisposing to familial psoriasis by using a stratification approach.

We have performed a genome scan, using markers spaced by 10 cM, in the search for psoriasis-susceptibility loci. The family material of 134 affected sibling pairs was ascertained on the basis of a population genetic study in which 65% of the probands had two healthy parents. Genotyping results were analyzed for non-random excessive allele-sharing between sib pairs by using GENEHUNTER ver 1.1. A stratification approach was applied to increase the homogeneity of the material by means of an operational definition of joint complaints among affected individuals. Significant linkage to the human leukocyte antigen region on chromosome 6p in a cohort including 42 families without joint complaints (nonparametric linkage score of 2.83, P=0.002) strongly supported the validity of this operational definition as it replicated results from an earlier linkage report with similar stratification criteria. New candidate regions on chromosomes 3 and 15 were identified. The highest non-parametric linkage values in this study, 2.96 (P=0.0017) and 2.89 (P=0.0020), were reached on chromosome 15 in a subgroup with joint complaints and on chromosome 3 in a subgroup without joint complaints. In addition, confirmation of previously reported loci was established on chromosomes 4q, 6p, and 17q. This study indicates that distinct disease loci might be involved in psoriasis etiology for various phenotypes.

Arthritis, Psoriatic↗
PubMed1999

Cytogenetic analysis of 477 psoriatics revealed an increased frequency of aberrations involving chromosome region 11q.

Psoriasis is an inflammatory skin disorder affecting approximately 3% of the population. Genetic studies published so far have shown a complex genetic inheritance with heterogeneity and a putative major susceptibility locus in the HLA region on chromosome 6. We have collected a large amount of material consisting mostly of small nuclear families in order to perform a genome-wide scan for psoriasis-associated genes. In order to focus the scan properly on possible candidate regions, we performed a cytogenetic analysis of 477 unrelated psoriatics. We divided our findings into sporadic, affecting a minor fraction of the cells, and constitutional, i.e. they were present in all cells examined. We found three cases of balanced translocation, all of which involved chromosome 11q. Two of these had a breakpoint in q12-13, whilst one involved the telomeric part of chromosome 11q. In order to characterise further the breakpoint on 11q12-13, we used bacterial artificial chromosomes (BACs) analysed by fluorescent in situ hybridisation (FISH). We were able to show that the persons had a close, but not identical breakpoints; they were separated by at least 5 cM. The major atopy locus is located in this region, as well as a locus for insulin-dependent diabetes mellitus, both being conditions with a pathogenetic mechanism involving antigen presentation.

Adolescent↗
PubMed1999

Analysis of three suggested psoriasis susceptibility loci in a large Swedish set of families: confirmation of linkage to chromosome 6p (HLA region), and to 17q, but not to 4q.

Psoriasis is known to be a heterogeneous disease with so far three reported major psoriasis susceptibility loci on chromosome 4q, 6p and 17q. In this study we investigated three reported gene locations by nonparametric and parametric linkage analysis in a large family set consisting of 104 families (153 sib pairs) from Sweden. We could confirm linkage to chromosome 6p. A maximum heterogeneous lod score of 2.78 was reached at locus D6S276 (alpha = 0.60). Allelic association studies within the HLA region indicated linkage disequilibrium at locus TNFbeta with a significant p value of 0.0009. Furthermore, we obtained weak evidence of linkage to the locus on chromosome 17q while no evidence of linkage could be found to the chromosome 4q region.

Chromosomes, Human, Pair 17↗
PubMed1997

Radiation doses and image information in digital pelvimetry with a phosphorous screen.

PURPOSE: The aim of the investigation was to determine the patient dose in digital pelvimetry by means of a phosphorous screen as compared to a screen-film combination of very high sensitivity. MATERIAL AND METHODS: Entrance dose measurements and absorbed dose determinations in a series of patient exposures were made. In the first series the exposure reduction was achieved by reducing the mAs (tube current x exposure time) for the lateral and the a.p. views as compared with those used for the screen-film system. In the second series the tube potential, kV, was increased for both projections in order to increase the penetration capacity of the radiation. RESULTS AND CONCLUSION: The imaging plate technique can be used in pelvimetry with a dose reduction (and a corresponding reduction of the radiation risk to the foetus) to less than 50% of that achieved with a screen-film system of the very highest sensitivity.

Female↗
PubMed1997

Trunk rotation in scoliosis. The influence of curve type and direction in 150 children.

We compared the angle of trunk rotation (ATR) from scoliometer readings with Cobb angle measurements of the lateral deviation of the spine in 150 children referred to hospital for evaluation of scoliosis. The mean Cobb angle in thoracic curves was 16 degrees. In thoracolumbar curves 17 degrees and in lumbar curves 20 degrees. In thoracic curves and in right convex curves no patient with a Cobb angle of 25 degrees or more had an ATR below 9 degrees. In thoracolumbar and lumbar and in left convex curves, 7 degrees ATR was occasionally associated with scoliosis of 25 degrees or more. The correlation coefficient between the ATR and Cobb angle in right convex curves was 0.65 compared to 0.57 in left convex curves. We conclude that a criterion of > 7 degrees ATR for thoracic or right convex curves and one of > 6 degrees ATR for thoracolumbar and lumbar or left convex curves seem adequate for identification of patients with Cobb angles of 25 degrees or more, which reduces the need for spinal radiography and follow-up outside the school screening programs.

Adolescent↗
PubMed1997

Genetic counselling in psoriasis: empirical data on psoriasis among first-degree relatives of 3095 psoriatic probands.

The risk of getting psoriasis dependent on the occurrence of psoriasis in the family has been determined empirically. Altogether 3717 families with one or both parents who had psoriasis have been analysed with regard to the number of children with or without psoriasis. The lifetime risk of getting psoriasis if no parent, one parent or both parents have psoriasis is 0.04, 0.28 and 0.65, respectively. If there is already one affected child in the family, the corresponding risks are 0.24, 0.51 and 0.83, respectively. The risk of getting psoriasis before the age of 32 years is dependent on the age-of-onset of psoriasis in one affected parent.

Adolescent↗
PubMed1996

Differential activation of lung-specific genes by two forkhead proteins, FREAC-1 and FREAC-2.

We describe the cDNA sequences for two human transcription factors, Forkhead RElated ACtivator (FREAC)-1 and -2, that belong to the forkhead family of eukaryotic DNA binding proteins. FREAC-1 and -2 are encoded by distinct genes, are almost identical within their DNA binding domains and in the COOH termini, but are otherwise divergent. Cotransfections with a reporter carrying FREAC binding sites showed that both proteins are transcriptional activators, and deletions located the activation domains to the COOH-terminal side of the forkhead domains. Expression of FREAC-1 and FREAC-2 is restricted to lung and placenta. We show that the promoters of genes for lung-specific proteins such as pulmonary surfactant proteins A, B, and C (SPA, SPB, and SPC) and the Clara cell 10-kDa protein (CC10) contain potential binding sites for FREAC-1 and FREAC-2. DNaseI footprinting verified that FREAC proteins bind to the predicted sites in the CC10 and SPB promoters. While an SPB promoter construct could be transactivated by both FREAC-1 and FREAC-2, CC10 was only activated by FREAC-1. Efficient activation of CC10 by FREAC-1 is shown to be specific for a lung cell line with Clara cell characteristics (H441) and to involve a region of the FREAC-1 protein unable to activate in other cell types.

Amino Acid Sequence↗
PubMed1995

Scoliosis as the first sign of a cystic spinal cord lesion.

We reviewed the cases of ten patients with scoliosis as the first sign of a cystic spinal cord lesion with the aim of identifying and studying early patient and curve characteristics. All patients were examined with magnetic resonance (MR) imaging of the brain and spinal cord and quantitative thermal testing (QTT). The mean Cobb angle was 22 degrees and the curves were right thoracic in seven patients, left thoracic in two, and left lumbar in one, when first seen for scoliosis. In six patients the cystic lesion was found in routine screening for syringomyelia, which is performed in all cases of congenital and juvenile scoliosis and in adolescent scoliosis before bracing. In four patients, it took up to 17 years following the initial diagnosis of scoliosis before neurologic deterioration warranted MR imaging, disclosing two Chiari I associated syrinxes and two cystic spinal cord tumors. QTT revealed a subclinically decreased sensation in two of the patients with no findings other than scoliosis. It also verified the decreased sensation in all patients in whom neurologic deterioration had complicated the clinical course of their scoliosis. More frequent spinal MR screening of patients with supposed juvenile or adolescent idiopathic scoliosis is indicated, regardless of curve type, to exclude a neurogenic cause. QTT documents subclinical as well as overt decreased sensation, and is valuable in the serial follow-up of these patients to monitor the progress or the response to treatment of the cystic lesion.

Adolescent↗
PubMed1994

Cloning and characterization of seven human forkhead proteins: binding site specificity and DNA bending.

The forkhead domain is a monomeric DNA binding motif that defines a rapidly growing family of eukaryotic transcriptional regulators. Genetic and biochemical data suggest a central role in embryonic development for genes encoding forkhead proteins. We have used PCR and low stringency hybridization to isolate clones from human cDNA and genomic libraries that represent seven novel forkhead genes, freac-1 to freac-7. The spatial patterns of expression for the seven freac genes range from specific for a single tissue to nearly ubiquitous. The DNA binding specificities of four of the FREAC proteins were determined by selection of binding sites from random sequence oligonucleotides. The binding sites for all four FREAC proteins share a core sequence, RTAAAYA, but differ in the positions flanking the core. Domain swaps between two FREAC proteins identified two subregions within the forkhead domain as responsible for creating differences in DNA binding specificity. Applying a circular permutation assay, we show that binding of FREAC proteins to their cognate sites results in bending of the DNA at an angle of 80-90 degrees.

Amino Acid Sequence↗