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Biomedical subjects

S K Hansen

Publications and source records attributed to S K Hansen.

At least 19 recordsLinked to original sources
PubMed2005

Variation near the hepatocyte nuclear factor (HNF)-4alpha gene associates with type 2 diabetes in the Danish population.

AIMS/HYPOTHESIS: The hepatocyte nuclear factor (HNF)-4alpha is an orphan nuclear receptor, which plays crucial roles in regulating hepatic gluconeogenesis and insulin secretion. The gene encoding HNF-4alpha (HNF4A) is located on chromosome 20q12-q13 in a region that in several studies has shown linkage with type 2 diabetes. Recently, two independent studies identified single nucleotide polymorphisms (SNPs) in a 90-kb region spanning HNF4A, which showed strong association with type 2 diabetes in the Finnish and Ashkenazi Jewish populations. In an attempt to replicate and extend these findings, we selected four SNPs in the same HNF4A region, which in the Finnish and Ashkenazi Jewish populations were associated with type 2 diabetes, and examined their relationships with type 2 diabetes and prediabetic phenotypes in the Danish Caucasian population. METHODS: The rs1884614, rs2425637, rs1885088 and rs3818247 were analysed in case-control studies of 1387, 1429, 1417 and 1371 type 2 diabetic patients and 4766, 4727, 4665 and 4748 glucose-tolerant subjects respectively. Genotype-quantitative trait analyses comprised 4430, 4394, 4336 and 4413 middle-aged glucose-tolerant subjects from the population-based Inter99 cohort for the rs1884614, rs2425637, rs1885088 and rs3818247 respectively. RESULTS: The risk allele of the rs1884614, which is located 4 kb upstream of the HNF4A P2 promoter, was associated with type 2 diabetes (odds ratio [OR]=1.14, p=0.02) and with a subtle increase in post-OGTT plasma glucose levels in glucose-tolerant subjects (additive model, p=0.05). CONCLUSIONS/INTERPRETATION: Consistent with results from studies of Finnish and Ashkenazi Jewish subjects, variation near the P2 region of HNF4A is associated with type 2 diabetes in the Danish population.

Cohort Studies↗
PubMed2005

Studies of relationships between variation of the human G protein-coupled receptor 40 Gene and Type 2 diabetes and insulin release.

AIMS: Recently, a novel human G protein-coupled receptor 40 (GPR40), which is predominantly expressed in pancreatic islets, was shown to mediate an amplifying effect of long-chain fatty acids on glucose-induced insulin secretion. The present aim was to examine the coding region of GPR40 for variation and to assess whether identified variants confer an increased risk of Type 2 diabetes or altered insulin release. METHODS: Mutation analysis was performed in 43 patients with Type 2 diabetes, 18 normal glucose-tolerant subjects, and 3 maturity-onset of diabetes in the young (MODY) X patients using direct sequencing. Genotyping was performed using polymerase chain reaction (PCR)-generated primer extension products analysis by high throughput chip-based mass spectrometry (MALDI-TOF). The potential impact of GPR40 mutations on [(3)H]-myo-inositol turnover was estimated in COS-7 cells after stimulation with various concentrations of 5,8,11-eicosatriynoic acid. RESULTS: Two nucleotide substitutions, an Arg211His polymorphism and a rare Asp175Asn mutation, were identified. Both variants showed EC(50) values similar to the wild type. However, the maximal efficacy of the rare Asp175Asn was 39% lower compared with the wild type (P = 0.01). The Arg211His polymorphism had a similar allele frequency among 1384 Type 2 diabetic patients [MAF%; 23.4 (95% CI: 21.8-25.0)] and 4424 middle-aged glucose-tolerant subjects [24.1% (23.2-25.0)]. A genotype-quantitative trait study of 5597 non-diabetic, middle-aged subjects from the Inter99 cohort showed no significant differences in oral glucose tolerance test (OGTT)-derived estimates of insulin release between carriers of various GPR40 genotypes. CONCLUSIONS: Variations in the coding region of GPR40 do not appear to be associated with Type 2 diabetes or insulin release alterations.

Case-Control Studies↗
PubMed2004

Large-scale studies of the HphI insulin gene variable-number-of-tandem-repeats polymorphism in relation to Type 2 diabetes mellitus and insulin release.

AIMS/HYPOTHESIS: The class III allele of the variable-number-of-tandem-repeats polymorphism located 5' of the insulin gene (INS-VNTR) has been associated with Type 2 diabetes and altered birthweight. It has also been suggested, although inconsistently, that the class III allele plays a role in glucose-induced insulin response among NGT individuals. METHODS: We investigated the impact of the class III allele on Type 2 diabetes susceptibility in a case-control study involving 1462 Type 2 diabetic patients and 4931 NGT subjects. We also examined the potential impact of the class III allele in genotype-quantitative trait studies in three Danish study populations containing (i) 358 young healthy subjects; (ii) 4444 middle-aged NGT subjects, 490 subjects with IFG and 678 subjects with IGT; and (iii) 221 NGT subjects, of whom one parent had Type 2 diabetes. RESULTS: There was no difference in frequency of the class III allele or in genotype distribution between the 1462 Type 2 diabetic patients and the 4931 NGT subjects. Among the 358 young subjects the class III/III carriers had significantly reduced post-IVGTT acute serum insulin and C-peptide responses (p=0.04 and 0.03 respectively). However, among the 4444 middle-aged subjects we failed to demonstrate any association between the class III allele and post-OGTT serum insulin and C-peptide levels. CONCLUSIONS/INTERPRETATION: The class III allele of the INS-VNTR does not confer susceptibility to Type 2 diabetes or consistent alterations in glucose-induced insulin release in the examined populations, which consisted of Danish Caucasians.

Adult↗
PubMed2003

Studies of variability in the islet amyloid polypeptide gene in relation to Type 2 diabetes.

AIMS: To explore whether the coding region of the islet amyloid polypeptide (IAPP) gene contains genetic variants associated with Type 2 diabetes and whether a previously reported association of the promoter variant -132g-->a with Type 2 diabetes could be reproduced in Danish Caucasians. METHODS: The coding region was analyzed using single strand conformation polymorphism (SSCP) and heteroduplex analysis in 192 Type 2 diabetic patients. Restriction fragment length polymorphism (RFLP) was employed to screen for the promoter variant in 414 Type 2 diabetic patients and 182 glucose-tolerant control subjects. RESULTS: The SSCP analysis identified an IVS+75a-->g variant in two patients. The frequency of heterozygous carriers of the promoter variant in the case-control study was 4.1% (17/414) and 7.1% (13/182), respectively. Odds ratio of the prevalence of Type 2 diabetes in carriers compared with non-carriers was estimated to be 0.47 (95% confidence interval 0.19, 1.15). CONCLUSION: Neither variability in the coding region of the IAPP gene nor the -132g-->a promoter variant was associated with Type 2 diabetes among the studied Danish Caucasians.

Amyloid↗
PubMed1998

[Kawasaki syndrome in an adult].

Kawasaki syndrome (KS) is an acute, febrile, exanthemous illness characterized by vasculitis of unknown origin mostly seen in children younger than four years of age. We describe a 24-year-old white male who fulfilled the diagnostic criteria for KS. In addition to the diagnostic symptoms of KS this patient had symptoms from the liver and lungs.

Adult↗
PubMed1998

House dust mite antigen exposure of patients with atopic dermatitis of psoriasis.

We studied the amount of house dust antigen in the beds of 55 patients with atopic dermatitis, eleven patients with psoriasis and ten healthy volunteers using a commercial ELISA which can determine the amount of antigen from Dermatophagoides pteronyssinus, D. farinae and D. microseras expressed as nanogram (ng) antigen per gram of house dust. The World Health Organization has indicated that 10,000 ng house dust mite antigen per gram house dust can elicit an asthma attack in IgE-sensitized patients with asthma bronchiale. There are no recommendations for patients with atopic eczema. We observed no statistical significant differences between each group concerning the amount of house dust found in the beds or the amount of house dust mite antigen. However, there were very wide variations. Twenty-seven percent (15/55) of patients with atopic dermatitis and 27% (3/11) of psoriasis patients had levels of house dust mite antigen above 10,000 ng per gram of house dust compared with healthy volunteers (1/10). Half of the patients had a type I allergy to house dust mite antigen using prick tests. This group had a total serum IgE of 2,034 kU/I (median value) compared to 301 kU/I in the group without type I allergy to house dust mite antigen (p < 0.01). The exposure to house dust mite antigen was similar in the two groups. We conclude that only 1/4 of patients with atopic dermatitis are exposed to high levels of house dust mite antigen in their bed environment equal to what is found for patients with another scaling disorder (psoriasis). Patients who have an increased serum IgE have significantly increased type I allergy to house dust mite antigen even though their exposure is not different from patients with low IgE.

Adult↗
PubMed1997

Transcription properties of a cell type-specific TATA-binding protein, TRF.

Eukaryotic cells are thought to contain a single TATA-binding protein (TBP) that directs transcription by cellular RNA polymerases. Here we report a cell type-specific TBP-related factor (TRF) that can form a stable TRF/IIA/IIB TATA DNA complex and substitute for TBP in directing RNA polymerase II transcription in vitro. Transfection studies reveal that TRF can differentially mediate activation by some enhancer proteins but not others. Like TBP, TRF forms a stable complex containing multiple novel subunits, nTAFs. Antibody staining of embryos and polytene chromosomes reveals cell type-specific expression and gene-selective properties consistent with the shaker/male sterile phenotype of trf mutants. These findings suggest TRF is a homolog of TBP that functions to direct tissue- and gene-specific transcription.

Animals↗
PubMed1997

Drosophila TFIIE: purification, cloning, and functional reconstitution.

We present a physical and molecular genetic characterization of Drosophila melanogaster TFIIE (dTFIIE), a component of the basal RNA polymerase II transcription apparatus. We have purified dTFIIE to near homogeneity from nuclear extracts of Drosophila embryos and found that it is composed of two subunits with apparent molecular weights of 55 and 38 kDa. Peptide sequence information derived from the two subunits was used to isolate the corresponding cDNA clones, revealing that dTFIIE and human TFIIE share extensive amino acid similarity. Functional conservation was demonstrated by the ability of bacterially expressed dTFIIE to substitute for human TFIIE in an in vitro transcription assay reconstituted from purified components. Cytological mapping analysis shows that both subunits are encoded by single copy genes located on chromosome III.

Amino Acid Sequence↗
PubMed1997

[Milker's nodules].

Milker's nodule is a parapox virus infection seen mostly on the hands of dairy farmers. We saw 15 cases over a period of two years in the County of North Jutland. Clinically, milker's nodule goes through a papular, a nodular and a crusted stage. Most patients were seen when the infection was in the nodular stage, an often painful condition requiring treatment. Three patients developed an erythema multiformelike secondary eruption. Lesions from nine patients were removed for histological examination. The histology of all lesions was consistent with milker's nodule. In three of seven patients parapox virus was demonstrated by electron microscopy. Treatment was commonly curettage followed by cauterization.

Adult↗
PubMed1996

SREBP transcriptional activity is mediated through an interaction with the CREB-binding protein.

The sterol regulatory element binding proteins (SREBP-1 and -2) activate transcription of genes whose products are involved in the cellular uptake and synthesis of cholesterol. Although considerable effort has been exerted to define the events regulating the levels of active SREBP, little is known about the transcriptional cofactors mediating SREBP function. In an unbiased search for potential coactivators of SREBP, we isolated a protein of 265 kD from HeLa cells that directly bound SREBP-1 and SREBP-2. Peptide sequencing and Western blot analysis established that the 265-kD protein was CBP (CREB-binding protein), a recently identified transcriptional coactivator. The putative activation domain of SREBP was shown to bind specifically to amino-terminal domains of recombinant CBP and p300 (a CBP-related protein). Moreover, transfection studies demonstrated that CBP enhances the ability of SREBP to activate transcription of reporter genes in HeLa cells. Together, these data suggest that CBP mediates SREBP transcriptional activity, thus revealing a new step in the biochemical pathway regulating cholesterol metabolism.

Animals↗
PubMed1996

[Use of contraception and reasons for choosing abortion among abortion applicants].

The object of this study was to describe a group of women applying for legal abortion in relation to their use of contraception and reasons for choosing an abortion. During a period of 13 months (1991-92) a questionnaire was distributed to women applying for legal abortion at Hillerød Hospital in Denmark. Three hundred and thirty-nine women participated. Fifty-nine percent of the women had become pregnant although they had used contraception. As seen in other studies, women still state demographic factors as their most important reasons for choosing an abortion. Women with two or more children do not want to have more children. Single women do not want children without being in a stable relationship. Furthermore occupation and education were frequently stated as important reasons for having an abortion. Economy and housing were not main reasons but contributory factors. Thirty percent of the women expressed ambivalence about the choice of abortion at the time when the abort was due.

Abortion Applicants↗
PubMed1995

Multiple TAFIIs directing synergistic activation of transcription.

Coordinate activation of transcription by multiple enhancer binding factors is essential for the regulation of pattern formation during development of Drosophila melanogaster. Cell-free transcription reactions are described that recapitulate transcriptional synergism directed by the Drosophila developmental regulators Bicoid (BCD) and Hunchback (HB). Within the basal transcription factor complex TFIID, two specific targets, TAFII110 and TAFII60, served as coactivators to mediate transcriptional activation by these two enhancer binding proteins. A quadruple complex containing TATA binding protein (TBP), TAFII250, TAFII110, and TAFII60 mediated transcriptional synergism by BCD and HB, whereas triple TBP-TAFII complexes lacking one or the other target coactivator failed to support synergistic activation. Deoxyribonuclease I footprint protection experiments revealed that an integral step leading to transcriptional synergism involves the recruitment of TBP-TAFII complexes to the promoter by way of multivalent contacts between activators and selected TAFIIs. Thus, the concerted action of multiple regulators with different coactivators helps to establish the pattern and level of segmentation gene transcription during Drosophila development.

Animals↗
PubMed1995

DNA template and activator-coactivator requirements for transcriptional synergism by Drosophila bicoid.

The template and coactivator requirements for synergistic transcription directed by a single activator, Bicoid (BCD), bound to multiple sites have been determined. Mutagenesis studies in combination with protein binding experiments and reconstituted transcription reactions identified two independent activation domains of BCD that target different coactivator subunits (TAFII110 and TAFII60) of the basal transcription factor IID (TFIID). The presence of both coactivators is required for BCD to recruit the TATA binding protein (TBP)-TAF complex to the promoter and direct synergistic activation of transcription. Thus, contact between multiple activation domains of BCD and different targets within the TFIID complex can mediate transcriptional synergism.

Animals↗
PubMed1995

A Drosophila homolog of the yeast origin recognition complex.

Genes from Drosophila melanogaster have been identified that encode proteins homologous to Orc2p and Orc5p of the Saccharomyces cerevisiae origin recognition complex (ORC). The abundance of the Drosophila Orc2p homolog DmORC2 is developmentally regulated and is greatest during the earliest stages of embryogenesis, concomitant with the highest rate of DNA replication. Fractionation of embryo nuclear extracts revealed that DmORC2 is found in a tightly associated complex with five additional polypeptides, much like the yeast ORC. These studies will enable direct testing of the initiator-based model of replication in a metazoan.

Amino Acid Sequence↗
PubMed1995

TAFs and TFIIA mediate differential utilization of the tandem Adh promoters.

The D. melanogaster alcohol dehydrogenase (Adh) gene is transcribed from two tandem promoters that are differentially utilized at various stages during development. To determine the mechanism of promoter selectivity, we have analyzed the activity of the Adh promoters both in vitro and in transfected cells. We found that selective promoter utilization is controlled by distinct initiator elements. Reconstitution of Adh transcription with purified components requires a specific TBP-TAF complex that, in concert with TFIIA, directs differential Adh promoter transcription. Fractionation of this TBP-TAF complex reveals that TAFII150 is required for discrimination between the proximal and distal promoters. We propose a mechanism for regulating differential promoter utilization during Drosophila development that involves the recognition of specific initiator elements by TAFs in the TFIID complex.

Alcohol Dehydrogenase↗
PubMed1995

Ambivalence among women applying for abortion.

BACKGROUND: Our purpose was to characterize women expressing ambivalence when applying for abortion. MATERIAL AND METHODS: Data were collected, by self-administered questionnaires, from 339 women. Thirty percent were in doubt about the decision when the abortion was due. Socio-economic factors more often influenced the choice among ambivalent women than among those not in any doubt. RESULTS: Ambivalent women more often felt exposed to social pressure and some felt that the abortion was not their own choice. Their decision-making was marked by doubt during the entire process. CONCLUSIONS: There is a need for professional support during this decision-making process. Many of the ambivalent women stated that their decision might not have been the same under different personal circumstances.

Abortion Applicants↗
PubMed1994

Differential DNA sequence specificity and regulation of HIV-1 enhancer activity by cRel-RelA transcription factor.

The cRel-RelA and NF-kappa B (p50-RelA) transcription factors bind to a kappa B-like sequence termed Rel-related proteins binding element localized in the regulatory region of the human urokinase plasminogen activator (uPA) gene. This sequence is highly conserved in murine and porcine uPA genes where it retained the ability to associate with cRel-RelA. On the other hand, NF-kappa B binding was obtained with the human and porcine elements only. Methylation interference analysis showed that NF-kappa B and cRel-RelA had identical interference patterns. Mutational analysis showed that DNA binding was highly sensitive to mutations within the decameric Rel-related proteins binding element core site. However, alterations of nucleotides flanking the decameric IgK-kappa B motif, which preferentially associated with NF-kappa B, resulted in high affinity cRel-RelA binding both in vitro and in vivo. These data demonstrate that NF-kappa B and cRel-RelA have overlapping but distinct DNA sequence specificities. Bandshift analysis with HeLa and Jurkat cell extracts or with in vitro translated proteins revealed that the SV40-, HIV-1-, and interleukin-2 receptor alpha subunit kappa B elements efficiently associated with cRel-RelA, suggesting that this heterodimer may be involved in the regulation of several genes. Cotransfection studies of HIV-1 long terminal repeat-chloramphenicol acetyltransferase reporter DNA with RelA, cRel, and p50 expression vectors were performed in COS7 and U293 cells to analyze the ability of cRel-RelA to regulate HIV-1 enhancer activity. In vivo formation of the cRel-RelA complex resulted in specific stimulation of the viral enhancer at a level comparable with that obtained with NF-kappa B. These data suggest that activation of cellular cRel-RelA may play a critical role in the regulation of HIV-1 enhancer activity.

Animals↗