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S Jacobsen

Publications and source records attributed to S Jacobsen.

At least 37 records · Page 2Linked to original sources
PubMed2001

Biodegradable fibres spun from poly(lactide) generated by reactive extrusion.

Poly(lactide) (PLA) was spun both in a high speed spinning process with take-up velocities of 1000-5000 m min(-1) and in a spin drawing process at draw ratios of 4-6. The effect of the melt spinning conditions on the development of the structural hierarchy in the fibres and the relations to the textile physical properties were investigated. The PLA fibres were characterised with regard to the degree of crystallinity by DSC and WAXS, the orientation by WAXS and birefringence, and the stress-strain behaviour. The maximum physical break stress and the E-modulus observed in the spin drawn fibres were about 490 MPa and 6.3 GPa, respectively, at an elongation at break of 30%. The PLA was a copolymer of L-lactide (92 wt.%) and meso-lactide (8 wt.%) and was generated by reactive extrusion polymerisation. The PLA virgin pellets were analysed regarding their degradation during the spinning processes. Their thermal and rheological properties were determined by DSC and dynamic rheological measurements, respectively, to derive suitable parameters for the melt spinning processes.

Biodegradation, Environmental↗
PubMed2001

Classification of wheat varieties: use of two-dimensional gel electrophoresis for varieties that can not be classified by matrix assisted laser desorpiton/ionization-time of flight-mass spectrometry and an artificial neural network.

Analyzing a gliadin extract by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) combined with an artificial neural network (ANN) is a suitable method for identification of wheat varieties. However, the ANN can not distinguish between all different wheat varieties. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was applied to three pairs of wheat varieties, which can not be classified correctly by ANN. By 2-D PAGE the varieties in the three pairs can be discriminated and these six wheat varieties can be separated from each other, which could not be separated by MALDI-TOF-MS and NN.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2001

Identification of barley and rye varieties using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks.

Cereal varieties are normally identified using time-consuming methods such as visual examination of either the intact grain or one-dimensional electrophoretic patterns of the grain storage proteins. A fast method for identification of wheat (Triticum aestivum L.) varieties has previously been developed, which combines analysis of alcohol-soluble wheat proteins (gliadins) using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks. Here we have applied the same method for the identification of both barley (Hordeum vulgare L.) and rye (Secale cereale L.) varieties. For barley, 95% of the mass spectra were correctly classified. This is an encouraging result, since in earlier experiments only a grouping into subsets of varieties was possible. However, the method was not useful in the classification of rye, due to the strong similarity between mass spectra of different varieties.

Glutens↗
PubMed2001

Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in cereals.

An enzyme degrading cytokinins with isoprenoid side chain, previously named cytokinin oxidase, was purified to near homogeneity from wheat and barley grains. New techniques were developed for the enzyme activity assay and staining on native electrophoretic gels to identify the protein. The purified wheat enzyme is a monomer 60 kDa, its N-terminal amino-acid sequence shows similarity to hypothetical cytokinin oxidase genes from Arabidopsis thaliana, but not to the enzyme from maize. N6-isopentenyl-2-(2-hydroxyethylamino)-9-methyladenine is the best substrate from all the cytokinins tested. Interestingly, oxygen was not required and hydrogen peroxide not produced during the catalytic reaction, so the enzyme behaves as a dehydrogenase rather than an oxidase. This was confirmed by the ability of the enzyme to transfer electrons to artificial electron acceptors, such as phenazine methosulfate and 2,6-dichlorophenol-indophenol. 2,3-Dimethoxy-5-methyl-1,4-benzoquinone, a precursor of the naturally occurring electron acceptor ubiquinone, readily interacts with the enzyme in micromolar concentrations. Typical flavoenzyme inhibitors such as acriflavine and diphenyleneiodonium inhibited this enzyme activity. Presence of the flavin cofactor in the enzyme was confirmed by differential pulse polarography and by measuring the fluorescence emission spectrum. Possible existence of a second redox centre is discussed.

Amino Acid Sequence↗
PubMed2001

Association of beta2-glycoprotein I IgG and IgM antibodies with thrombosis and thrombocytopenia.

Antiphospholipid antibodies (APA) have been known for decades. Their relation to clinical manifestations, primarily thromboses and thrombocytopenia, was recognised in the 1980s. In this clinical study two cohorts of patients, a population-based (84 patients with systemic lupus erythematosus (SLE)) and a hospital-based (87 patients with SLE and 53 with other connective tissue diseases) were investigated for APA and associated clinical manifestations. Anticardiolipin antibodies (ACA) of IgG and IgM classes were found in 13 and 38% of the population-based patients and in 29 and 58% of the hospital-based patients, respectively. The corresponding figures for antibodies against beta2-glycoprotein I (anti-beta2GPI) were 15 and 10% in the population-based patients and 14 and 8% in the hospital-based cohort. Anti-beta2GPI antibodies were always found in association with the corresponding immunoglobulin class of ACA. In both cohorts anti-beta2GPI of the IgG class were associated with arterial/venous occlusion, a result concordant with other studies. A novel finding in both cohorts, however, was an association between thrombocytopenia and IgM anti-beta2GPI.

Adolescent↗
PubMed2001

The influence of mannose binding lectin polymorphisms on disease outcome in early polyarthritis. TIRA Group.

OBJECTIVE: To determine whether variant alleles of the mannose binding lectin (MBL) gene causing low serum concentrations of MBL are associated with increased susceptibility to rheumatoid arthritis (RA) and erosive outcome in an inception cohort of patients with early polyarthritis. METHODS: MBL and HLA-DRB1 alleles were determined by polymerase chain reaction in 68 Danish patients with incident early polyarthritis observed for one year. The associations between MBL and specific HLA-DRB1 genotypes and disease outcomes were analyzed. RESULTS: Among the patients with early polyarthritis 7.4% (5/68) and 41.2% (28/68) were homozygous and heterozygous for MBL variant alleles, compared with 2.8% (7/250) and 34.4% (86/250) of healthy controls (p = 0.09), while the corresponding figures in the patients with RA were 10% (5/50) and 42% (21/50) (p = 0.03), and in the patients with erosive RA 18.8% (3/16) and 35.3% (6/16), respectively (p = 0.004). Patients with early polyarthritis homozygous for MBL variant alleles had an increased risk of having erosive RA at inclusion by a factor of 4.7 (p = 0.02) and after one year by a factor of 3.6 (p = 0.04). MBL deficiency was associated with increased levels of C-reactive protein (CRP) and IgM rheumatoid factor (RF) at inclusion (p < 0.05). HLA-DRB1 alleles were not found to be associated with disease outcome. CONCLUSION: MBL variant alleles appear to be weak susceptibility markers for RA, and patients with early polyarthritis and homozygous for MBL structural variant alleles have a higher risk of developing early erosive RA. These findings, together with the positive association between MBL variant alleles and the increased serum levels of IgM RF and CRP, point at the MBL gene as a relevant locus in the pathophysiology of RA.

Adult↗
PubMed2001

Influence of clinical features, serum antinuclear antibodies, and lung function on survival of patients with systemic sclerosis.

OBJECTIVE: To evaluate the independent contribution of several clinical and laboratory variables to the mortality of a cohort of Danish patients with systemic sclerosis (SSc). METHODS: A cohort of 174 patients with incident SSc was retrospectively identified using clinical charts and study records of all new patients with SSc. Disease onset was defined as the time of onset of cutaneous sclerosis. Vital status and causes of death were determined at the end of the observation period. Data on clinical status and pulmonary function were obtained. Antitopoisomerase I (anti-topo I), anticentromere, anti-U1-RNP, anti-U3-RNP, anti-Th-RNP, and anti-RNA polymerase (anti-RNAP) antibodies were determined by means of double immunodiffusion, immunofluorescence, hemagglutination technique, radioactively labelled antisense riboprobes, and ELISA, respectively. RESULTS: Patients were followed for a mean period of 13.3 yrs; 16 died of an SSc related condition and 50 of other causes. Pulmonary fibrosis, DLCO reduction < 40% of the expected, diffuse cutaneous involvement, SSc nephropathy, cardiac disease, and anti-topo I and anti-RNAP antibody were related to decreased survival due to SSc. Variables that entered a Cox regression model of SSc related mortality were right heart failure (RR 12.4, 95% CI 2.5-60), diffuse SSc (RR 7.8, 95% CI 1.8-35), SSc nephropathy (RR 6.1, 95% CI 1.8-21), and DLCO < 40% (RR 4.8, 95% CI 1.1-20). The relative risk of developing right heart failure and diffuse SSc given the presence of anti-RNAP antibody was 14 (p = 0.0001) and 1.9 (p = 0.01), respectively. The corresponding figures for anti-topo I antibody were 4.6 (p = 0.02) and 2.0 (p = 0.01). CONCLUSION: SSc related mortality was associated with right heart failure and diffuse SSc, both of which were also associated with the presence of anti-topo I and anti-RNAP antibody. The prognostic value of these autoantibodies may lie in the early course of the disease when specific morbidity has not yet evolved.

Adolescent↗
PubMed2000

Characterisation of a homogeneous plant aminoaldehyde dehydrogenase.

According to our knowledge, this is the first purification method developed, enabling isolation of a homogeneous aminoaldehyde dehydrogenase (AMADH) from etiolated pea seedlings. The procedure involved initial purification with precipitants followed by three low pressure chromatographic steps. Partially purified enzyme was further subjected to fast protein liquid chromatography on a Mono Q column and to affinity-interaction chromatography on 5'-AMP Sepharose. Purity of the final enzyme preparation was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and chromatofocusing. Pea AMADH exists as a tetramer of 230 kDa in the native state, a molecular mass of one subunit was determined as 57 kDa. The enzyme was found to be an acidic protein with pI 5.4. AMADH showed a broad substrate specificity utilising various aminoaldehydes (C3-C6) as substrates. The best substrate of pea AMADH was 3-aminopropionaldehyde, the enzyme also efficiently oxidised 4-aminobutyraldehyde and omega-guanidinoanalogues of the aminoaldehydes. Pea AMADH was inhibited by SH reagents, several elementary aldehydes and metal-binding agents. Although AMADH did not oxidise betaine aldehyde at all, the N-terminal amino acid sequence of the enzyme shows a high degree of homology with those of plant betaine aldehyde dehydrogenases (BADHs) of spinach, sugar beet and amaranth. Several conserved amino acids were found in comparison with BADH from cod liver of known crystal structure.

Aldehyde Oxidoreductases↗
PubMed2000

[Use of glucocorticoids in rheumatoid arthritis].

OBJECTIVES: To determine whether short-term (i.e. as recorded within the first month of therapy), oral low-dose corticosteroids (corresponding to a maximum of 15 mg prednisolone daily) is superior to placebo and nonsteroidal, antiinflammatory drugs in patients with rheumatoid arthritis. SEARCH STRATEGY: Medline Silverplatter, The Cochrane Controlled Trials Register, reference lists and a personal archive. SELECTION CRITERIA: All randomised studies comparing an oral corticosteroid (not exceeding an equivalent of 15 mg prednisolone daily) with placebo or a nonsteroidal, antiinflammatory drug were eligible if they reported clinical outcomes within one month after start of therapy. DATA COLLECTION AND ANALYSIS: Decisions on which trials to include were made independently by two observers based on the methods sections of the trials only. Standardised effect measures were used for the statistical analyses; the random effects model was used if p < 0.10 for the test of heterogeneity. MAIN RESULTS: Ten studies, involving 320 patients, were included in the meta-analysis. Prednisolone had a marked effect over placebo on joint tenderness (standardised effect size 1.31, 95% confidence interval 0.78 to 1.83), pain (standardised effect size 1.75, 0.87 to 2.64) and grip strength (standardised effect size 0.41, 0.13 to 0.69). Measured in the original units, the differences were 12 tender joints (6 to 18) and 22 mmHg (5 to 40) for grip strength. Prednisolone also had a greater effect than nonsteroidal, antiinflammatory drugs on joint tenderness (standardised effect size 0.63, 0.11 to 1.16) and pain (standardised effect size 1.25, 0.26 to 2.24), whereas the difference in grip strength was not significant (standardised effect size 0.31, -0.02 to 0.64). Measured in the original units, the differences were 9 tender joints (5 to 12) and 12 mmHg (-6 to 31). The risk of adverse effects, also during moderate- and long-term use, seemed acceptable. CONCLUSIONS: Prednisolone in low doses (not exceeding 15 mg daily) may be used intermittently in patients with rheumatoid arthritis, particularly if the disease cannot be controlled by other means. Since prednisolone is highly effective, short-term placebo controlled trials studying the clinical effect of low-dose prednisolone or other oral corticosteroids are no longer necessary.

Anti-Inflammatory Agents↗
PubMed2000

Mapping and identification of Mycobacterium tuberculosis proteins by two-dimensional gel electrophoresis, microsequencing and immunodetection.

Mycobacterium tuberculosis is the infectious agent giving rise to human tuberculosis. The entire genome of M. tuberculosis, comprising approximately 4000 open reading frames, has been sequenced. The huge amount of information released from this project has facilitated proteome analysis of M. tuberculosis. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was applied to fractions derived from M. tuberculosis culture filtrate, cell wall, and cytosol, resulting in the resolution of 376, 413, and 395 spots, respectively, in silver-stained gels. By microsequencing and immunodetection, 38 culture filtrate proteins were identified and mapped, of which 12 were identified for the first time. In the same manner, 23 cell wall proteins and 19 cytosol proteins were identified and mapped, with 9 and 10, respectively, being novel proteins. One of the novel proteins was not predicted in the genome project, and for four of the identified proteins alternative start codons were suggested. Fourteen of the culture filtrate proteins were proposed to possess signal sequences. Seven of these proteins were microsequenced and the N-terminal sequences obtained confirmed the prediction. The data presented here are an important complement to the genetic information, and the established 2-D PAGE maps (also available at: www.ssi.dk/publichealth/tbimmun) provide a basis for comparative studies of protein expression.

Amino Acid Sequence↗
PubMed2000

High resolution electroelution of polyacrylamide gels for the purification of single proteins from Mycobacterium tuberculosis culture filtrate.

Culture filtrate from Mycobacterium tuberculosis contains protective molecules which have been used successfully in experimental vaccines against tuberculosis. Despite an increasing number of mycobacterial proteins being characterised, a major effort is still needed to get an overview of the many potentially interesting molecules in culture filtrate. In this study we describe a high throughput method for purification and biological evaluation of protein components in complex protein mixtures. The method presents a new application of the recently developed Mini Whole Gel Eluter and employs this apparatus for the high resolution electroelution of selected molecular mass fractions of protein mixtures previously separated in large polyacrylamide gels. Two novel M. tuberculosis culture filtrate proteins (CspA and TB18.6) were purified by this method, their N-terminal sequences were determined and the open reading frame encoding each of the proteins identified. The immunological recognition of the molecules were evaluated in tuberculosis infected mice and guinea pigs. Both proteins induced DTH responses in guinea pigs and IFN-gamma release from spleen lymphocytes isolated from infected mice.

Amino Acid Sequence↗
PubMed2000

Dual-mode antenna design for microwave heating and noninvasive thermometry of superficial tissue disease.

Hyperthermia therapy of superficial skin disease has proven clinically useful, but current heating equipment is somewhat clumsy and technically inadequate for many patients. The present effort describes a dual-purpose, conformal microwave applicator that is fabricated from thin, flexible, multilayer printed circuit board (PCB) material to facilitate heating of surface areas overlaying contoured anatomy. Preliminary studies document the feasibility of combining Archimedean spiral microstrip antennas, located concentrically within the central region of square dual concentric conductor (DCC) annular slot antennas. The motivation is to achieve homogeneous tissue heating simultaneously with noninvasive thermometry by radiometric sensing of blackbody radiation from the target tissue under the applicator. Results demonstrate that the two antennas have complimentary regions of influence. The DCC ring antenna structure produces a peripherally enhanced power deposition pattern with peaks in the outer corners of the aperture and a broad minimum around 50% of maximum centrally. In contrast, the Archimedean spiral radiates (or receives) energy predominantly along the boresight axis of the spiral, thus confining the region of influence to tissue located within the central broad minimum of the DCC pattern. Analysis of the temperature-dependent radiometer signal (brightness temperature) showed linear correlation of radiometer output with test load temperature using either the spiral or DCC structure as the receive antenna. The radiometric performance of the broadband Archimedean antenna was superior compared to the DCC, providing improved temperature resolution (0.1 degree C-0.2 degree C) and signal sensitivity (0.3 degree C-0.8 degree C/degree C) at all four 500 MHz integration bandwidths tested within the frequency range from 1.2 to 3.0 GHz.

Biomedical Engineering↗
PubMed2000

Comparative evaluation of low-molecular-mass proteins from Mycobacterium tuberculosis identifies members of the ESAT-6 family as immunodominant T-cell antigens.

Culture filtrate from Mycobacterium tuberculosis contains protective antigens of relevance for the generation of a new antituberculosis vaccine. We have identified two previously uncharacterized M. tuberculosis proteins (TB7.3 and TB10.4) from the highly active low-mass fraction of culture filtrate. The molecules were characterized, mapped in a two-dimensional electrophoresis reference map of short-term culture filtrate, and compared with another recently identified low-mass protein, CFP10 (F. X. Berthet, P. B. Rasmussen, I. Rosenkrands, P. Andersen, and B. Gicquel. Microbiology 144:3195-3203, 1998), and the well-described ESAT-6 antigen. Genetic analyses demonstrated that TB10.4 as well as CFP10 belongs to the ESAT-6 family of low-mass proteins, whereas TB7.3 is a low-molecular-mass protein outside this family. The proteins were expressed in Escherichia coli, and their immunogenicity was tested in cultures of peripheral blood mononuclear cells from human tuberculosis (TB) patients, Mycobacterium bovis BCG-vaccinated donors, and nonvaccinated donors. The two ESAT-6 family members, TB10.4 and CFP10, were very strongly recognized and induced gamma interferon release at the same level (CFP10) as or at an even higher level (TB10.4) than ESAT-6. The non-ESAT-6 family member, TB7.3, for comparison, was recognized at a much lower level. CFP10 was found to distinguish TB patients from BCG-vaccinated donors and is, together with ESAT-6, an interesting candidate for the diagnosis of TB. The striking immunodominance of antigens within the ESAT-6 family is discussed, and hypotheses are presented to explain this targeting of the immune response during TB infection.

Amino Acid Sequence↗
PubMed2000

Determination of autoantibodies to annexin XI in systemic autoimmune diseases.

Annexin XI, a calcyclin-associated protein, has been shown to be identical to a 56,000 Da antigen recognized by antibodies found in sera from patients suffering from systemic autoimmune diseases. In this work hexahistidine-tagged recombinant annexin XI (His6- rAnn XI) was used as antigen in ELISA experiments for determination of autoantibodies to annexin XI in sera of patients with systemic rheumatic autoimmune diseases. Immunoblotting with HeLa cell extract and with His6-rAnn XI as antigen was used for confirmation of positive ELISA results. We found eleven anti-annexin XI positive sera (3.9%) out of 282 sera from patients with systemic rheumatic diseases. The highest number of annexin XI positive sera were found in primary antiphospholipid syndrome (3/17), and in subacute lupus erythematosus (1/6), while lower frequencies of positive sera were found in patients with systemic sclerosis (5/137), rheumatoid arthritis (1/21), and systemic lupus erythematosus (1/58). Sera from healthy donors and patients with chronic infections were negative, except for one Salmonella typhimurium antibody positive serum. Autoantibodies to annexin XI were found to relate to thrombosis, but not to other clinical or laboratory features. A relation between antibodies to annexins and thrombosis has so far only been known for annexin V.

Adult↗
PubMed2000

Calorie use and obesity among diabetic and non-diabetic Mvskoke Indians.

Type 2 diabetes is a major cause of death among American Indians and obesity and physical inactivity are modifiable risk factors in the development of type 2 diabetes. Physical activity may have both a preventive effect and a secondary preventive effect of lessening insulin resistance in persons with type 2 diabetes. Moreover, for some individuals participation in daily regimens of physical activity is very difficult. Culture-specific physical activity may be an intervention to reduce obesity and prevent diabetes-related complications. Therefore, the research questions for this study were: (1) What is the body fat percentage of diabetic and non-diabetic Mskoke Indians?, (2) How does body fat percentage of Mvskoke Indians compare with recommended percentages for age and gender?, (3) What is the caloric use of Mvskoke Indians during daily and traditional cultural activities of dancing and stickball?, and (4) Are there relationships among body fat percentage, calorie use, gender, and diabetic status? The findings revealed that female diabetics' percentage of body fat in three age cohorts (40-49, 50-59, and 70+) was higher than that of non-diabetic females. By contrast, male diabetics had lower percentage of body fat than non-diabetic males. The actual mean percentage of body fat of the female participants ranged from 38.5% to 44%, roughly twice the standard recommended percentages of body fat of 20-24%. No significant difference was found in calorie use by gender or diabetic status. Analysis of calories during traditional activities revealed that 30 minutes of stickball used an average of 135.7 calories. Dancing for 33 minutes used an average of 149 calories. No significant relationship was found among percentage of body fat, caloric use, gender, and diabetic status.

Adolescent↗