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Biomedical subjects

A Hansen

Publications and source records attributed to A Hansen.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Pregnancy associated pelvic pain. I: Prevalence and risk factors].

With this study, we wanted to determine the incidence of symptom-giving pelvic girdle relaxation during pregnancy and the prevalence post partum, identify predisposing factors, and determine the frequency of sick leave. A total of 1600 pregnant women entered the study. The incidence during pregnancy was 14%, the prevalence two, six, and twelve months post partum was 5%, 4%, and 2%, respectively. Multivariate analysis indicated that the most important predisposing factor was pelvic pain in a previous pregnancy. Other factors were uncomfortable working conditions, lack of exercise, and previous low back and low abdominal pain. At least 37% of the women with symptom-giving pelvic girdle relaxation were on sick leave during pregnancy, on average for twelve weeks. Symptom-giving pelvic girdle relaxation is a considerable problem both in pregnancy and post partum. The occupational risk can possibly be prevented. The syndrome has a great social impact because of the high frequency of sick live.

Adult↗
PubMed2000

[Pregnancy associated pelvic pain. II: Symptoms and clinical findings].

Pelvic pain in pregnancy appears to be a problem on the increase. This study was undertaken to describe and analyse the relationship between subjective symptoms, daily disability, and clinical findings in women with symptom-giving pelvic girdle relaxation in pregnancy. Out of 1600 pregnant women, 238 had pelvic pain. After a clinical examination 11 women were excluded due to low back pain. The rest, 227 women, was considered to have symptom-giving pelvic girdle relaxation during pregnancy. Symptom-giving pelvic girdle relaxation in pregnancy seriously interferes with many activities of daily living such as housekeeping, walking, working, and sexual life. The women's statements of pelvic pain are well correlated to the number of positive clinical tests. Symptom-giving pelvic girdle relaxation in pregnancy causes considerable disabilities concerning daily activities.

Adult↗
PubMed2000

Viscous stabilization of 2D drainage displacements with trapping

We investigate the stabilization mechanisms due to viscous forces in the invasion front during drainage displacement in two-dimensional porous media using a network simulator. We find that in horizontal displacement the capillary pressure difference between two different points along the front varies almost linearly as a function of height separation in the direction of the displacement. The numerical result supports arguments taking into account the loopless displacement pattern where nonwetting fluid flows in separate strands (paths). As a consequence, we show that existing theories developed for viscous stabilization are not compatible with drainage when loopless strands dominate the displacement process.

Journal Article↗
PubMed2000

Pathways in two-state protein folding.

Thermodynamic measurements of proteins indicate that the folding to the native state takes place either through stable intermediates or through a two-state process without intermediates. The rather short folding times of proteins indicate that folding is guided through some sequence of contact bindings. We discuss the possibility of reconciling a two-state folding event with a sequential folding process in a schematic model of protein folding. We propose a new dynamical transition temperature that is lower than the temperature at which proteins in equilibrium unfold. This is in qualitative agreement with observations of in vivo protein folding activity quantified by chaperone concentration in Escherichia coli. Finally, we discuss our framework in connection with the unfolding of proteins at low temperatures.

Biophysical Phenomena↗
PubMed2000

CEA-related cell adhesion molecule 1: a potent angiogenic factor and a major effector of vascular endothelial growth factor.

CEA-related cell adhesion molecule 1 (CEACAM1) exhibits angiogenic properties in in vitro and in vivo angiogenesis assays. CEACAM1 purified from granulocytes and endothelial cell media as well as recombinant CEACAM1 expressed in HEK293 cells stimulate proliferation, chemotaxis, and capillary-like tube formation of human microvascular endothelial cells. They increase vascularization of chick chorioallantoic membrane and potentiate the effects of vascular endothelial growth factor (VEGF)165. VEGF165 increases CEACAM1 expression both on the mRNA and the protein level. VEGF165-induced endothelial tube formation is blocked by a monoclonal CEACAM1 antibody. These data suggest that CEACAM1 is a major effector of VEGF in the early microvessel formation. Since CEACAM1 is expressed in tumor microvessels but not in large blood vessels, CEACAM1 may be a target for the inhibition of tumor angiogenesis.

Adenosine Triphosphatases↗
PubMed2000

Content of phenolic acids and ferulic acid dehydrodimers in 17 rye (Secale cereale L.) varieties.

The contents of pnenolic acids and ferulic acid dehydrodimers were quantified by HPLC analysis after alkaline hydrolysis in kernels of 17 rye (Secale cereale L.) varieties grown in one location in Denmark during 1997 and 1998. Significant variations (P < 0.05) with regard to the concentration of the analyzed components were observed among the different rye varieties and also between different harvest years. However, the content of phenolic acids in the analyzed rye varieties was narrow compared to cereals such as wheat and barley. The concentration of ferulic acid, the most abundant phenolic acid ranged from 900 to 1170 microgram g(-1) dry matter. The content in sinapic acid ranged from 70 to 140 microgram g(-1) dry matter, p-coumaric acid ranged from 40 to 70 microgram g(-1) dry matter, and caffeic, p-hydroxybenzoic, protocatechuic, and vanillic acids were all detected in concentrations less than 20 microgram g(-1) dry matter. The most abundant ferulic acid dehydrodimer 8-O-4 -DiFA was quantified in concentrations from 130 to 200 microgram g(-1) dry matter followed by 8,5 -DiFA benzofuran form (50-100 microgram g(-1) dry matter), 5,5 -DiFA (40-70 microgram g(-1) dry matter), and 8,5 -DiFA (20-40 microgram g(-1) dry matter).

Bread↗
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

A simple method to establish short-term cultures of normal human colonic epithelial cells from endoscopic biopsy specimens. Comparison of isolation methods, assessment of viability and metabolic activity.

BACKGROUND: Abnormalities in colonic epithelial cell function have been implicated in the pathogenesis of various intestinal disorders, especially inflammatory bowel disease (IBD). The mechanisms, however, remain obscure owing to the lack of representative human colonic epithelial cell models. The aim of this study was to develop and validate a method for establishment of short-term culture of normal human colonic epithelial cells from endoscopic biopsies. METHODS: Epithelial cells were isolated from colonoscopic biopsies by means of ethylenediaminetetraacetic acid/ethylene glycol tetraacetic acid (EDTA/EGTA) (10 or 60 min) or by enzyme treatment and cultured in collagen-coated wells. Viability was measured with a methyltetrazoleum conversion assay, confocal laser, and electron microscopy. Metabolic function was measured by means of butyrate oxidation, 14C-leucine and 3H-glucosamine incorporation; DNA synthesis by means of 3H-thymidine incorporation, and apoptosis with an enzyme-linked immunosorbent assay (ELISA) for histone-associated DNA fragments. Cell types were identified by immunocytochemistry. RESULTS: Ten minutes of EDTA/EGTA treatment released intact crypts and was superior to both the 60-min treatment and enzymatic treatment in terms of viability and nonepithelial cell contamination, respectively. Despite activation of detachment-induced apoptosis, a median 51% of the isolated cells was viable after 24 h of culture and metabolically active as judged by 3H-thymidine, 14C-leucine, and 3H-glucosamine incorporation. Butyrate oxidation followed more complex kinetics (substrate activation) than observed previously in other models. The apparent Km values (medians) were 0.7 mM and 4.5 mM in low and high concentration ranges, respectively. CONCLUSION: We report a simple method to establish culture of human colonic epithelial cells from endoscopically obtained biopsy specimens, producing sufficient viable cells to perform metabolic studies pertinent to the pathogenesis of IBD and related human disorders.

Biopsy↗
PubMed2000

Geometry and dynamics of invasion percolation with correlated buoyancy

We study an invasion percolation model for drainage where the disorder comes partly from capillary thresholds and partly from height differences in a rough self-affine landscape. As a function of the buoyancy, the geometry of the invaded clusters changes dramatically. Long-range correlations from the fracture topography induce a double cluster structure with strings and compact blobs. A characteristic length is introduced comparing the width of the capillary threshold distribution and gravity effects at the pore scale. We study electrical properties of percolating clusters. Current distributions along percolating clusters are shown to be multifractal and sensitive to the buoyancy.

Journal Article↗
PubMed2000

Phyletic distribution of crypt-type olfactory receptor neurons in fishes.

The olfactory epithelium of teleost fishes contains ciliated and microvillous olfactory receptor neurons intermingled with supporting cells. Recently the crypt cell, a third type of olfactory receptor neuron (ORN), was described for two ostariophysans. This type of ORN bears apical microvilli as well as occult cilia extending into a crypt at the apex of the cell. The present study used scanning and transmission electron-microscopic methods to examine how widespread this cell type is in other groups of fish. We investigated the olfactory epithelia of 18 species, freshwater and marine, including various actinopterygian fish as well as 2 species of lungfishes belonging to the sarcopterygians. Crypt cells were detected in 13 species of actinopterygian fish, but in none of the sarcopterygian lungfishes. Crypt cells are present in basic as well as in highly derived actinopterygians. We conclude that crypt cells are a common feature of actinopterygian fish.

Animals↗
PubMed2000

Use of immunoglobulin variable-region genes by normal subjects and patients with systemic lupus erythematosus.

Antibodies to specific autoantigens are serological hallmarks of systemic autoimmune diseases. These autoantibodies are thought to represent a consequence of immune dysregulation in these conditions, and, in part, have been shown to be involved in their pathologic consequences. However, the mechanisms that lead to the production of autoantibodies are still unknown. The observation that certain autoantibodies are frequently encoded by a limited number of immunoglobulin (Ig) variable-region gene segments suggested that a bias in the development of the Ig repertoire might play a role in the tendency to develop autoimmunity. Whether the use of these individual gene segments is random or different in normal subjects and patients with systemic autoimmune disorders remains a matter of controversy. New approaches for the analysis of variable-region genes from unstimulated individual human B cells employing the single-cell polymerase chain reaction have provided new insights in the B cell repertoire of both normal subjects and patients with systemic autoimmune diseases. Using this approach, the analysis of nonproductive and productive Ig variable-region gene rearrangements made it possible to distinguish molecular processes, as manifested in the nonproductive repertoire, from subsequent selection influences. An initial study in a patient with systemic lupus erythematosus has led to the hypothesis that the molecular generation of the B cell repertoire is similar in patients and normal subjects but subsequent influences and, most notably, extensive mutations and receptor editing differ significantly in shaping the peripheral IgV gene use by persons with autoimmune diseases.

Animals↗
PubMed2000

Enhanced mutational activity and disturbed selection of mutations in V(H) gene rearrangements in a patient with systemic lupus erythematosus.

To determine the impact of somatic hypermutation and selective influences on the V(H) gene repertoire in SLE, the mutational frequency and pattern of mutations in nonproductively and productively rearranged V(H) genes obtained from genomic DNA of individual CD19+ B cells were analyzed in a patient with SLE. The mutational frequencies of nonproductive (6.54 x 10(-2)) as well as of productive (4.38 x 10(-2)) V(H) rearrangements were significantly higher in the SLE patient than in normal controls (3.8 x 10(-2), p<0.001 and 3.3 x 10(-2); p<0.001, respectively). Analysis of nonproductive rearrangements documented only minor abnormalities of the targeting of the mutator in the SLE patient. The majority of "mutational hot spots", although different than in normals, appeared in the CDRs and an increased frequency of mutations in RGYW/WRCY sequences was observed. Moreover, no biases in base pair changes were found in the nonproductive repertoire. In contrast, there was a selection against A and T mutations and towards G mutations within the productive repertoire. Importantly, there were no significant differences in the R/S ratios of mutations within the FRs between the nonproductive and productive repertoire consistent with abnormalities in elimination of B cells expressing V(H) genes with these mutations. The result of this abnormality was a significantly higher R/S ratio of the V(H)genes in the productive repertoire of the SLE patient compared to normals (p<0.05). These data indicate that the mutational machinery was markedly enhanced in this SLE patient but exhibited nearly normal targeting, whereas selective influences were abnormal. These findings suggest that both enhanced mutational activity and disturbances in selection may have played a role in the emergence of autoreactivity in this SLE patient.

Amino Acid Substitution↗
PubMed1999

Rate- and site-dependent effects of propafenone, dofetilide, and the new I(Ks)-blocking agent chromanol 293b on individual muscle layers of the intact canine heart.

BACKGROUND: Recent in vitro studies have demonstrated regional differences in electrophysiological properties of individual left ventricular muscle layers. Controversy exists on the relevance of these findings for the situation in vivo. Thus, this study was designed to determine whether the in vivo canine heart exhibits regional differences in left ventricular refractoriness and in the susceptibility to sodium and potassium channel blockers. METHODS AND RESULTS: In 16 dogs, 36 needle electrodes (12 mm long, 4 bipolar electrodes, interelectrode distance 2.5 mm) were inserted into the left ventricular wall. By use of a computerized multiplexer-mapping system, the spread of activation in epicardial, endocardial, and midmyocardial muscle was reconstructed during ventricular pacing at 300- and 850-ms basic cycle length (BCL). Effective refractory periods (ERPs) were determined at baseline and after application of propafenone (2 mg/kg), dofetilide (30 microg/kg), or chromanol 293b (10 mg/kg) by the extrastimulus technique (BCL 300 and 850 ms). At baseline, activation patterns and ERPs were uniform in all muscle layers. Propafenone homogeneously decreased conduction velocity and moderately prolonged ERPs without any regional differences. Dofetilide and chromanol 293b did not affect the spread of activation. Dofetilide exhibited reverse use-dependent effects on ERP, still preserving transmural homogeneity of refractoriness. Chromanol 293b led to a regionally uniform but more pronounced increase in local ERPs at faster than at slower pacing rates. CONCLUSIONS: At the heart rates applied, the in vivo canine heart does not exhibit regional differences in electrophysiological properties. Given the homogeneity of antiarrhythmic drug effects, induction of local gradients of refractoriness is obviously not a common mechanism of proarrhythmia in normal hearts.

Animals↗
PubMed1999

Thymic transplantation across an MHC class I barrier in swine.

Thymic tissue transplantation has been performed previously in adult mice to induce donor-specific tolerance across allogeneic and xenogeneic barriers. We have now attempted to extend this technique to a large animal preclinical model and describe here our initial studies of allogeneic thymic transplantation in miniature swine. Two miniature swine were thymectomized before thymic tissue transplantation, and two remained euthymic. Donor thymic tissue was harvested from SLA class I-mismatched juvenile pigs and placed into recipient sternocephalicus muscle, kidney capsule, and omentum. A 12-day course of cyclosporin A was started on the day of transplantation. Allogeneic thymic engraftment could only be achieved in euthymic and not in thymectomized miniature swine using this treatment regimen. Both nonthymectomized animals showed good graft development, with evidence of thymopoiesis, as indicated by positive CD1 and host-type SLA class I immunoperoxidase staining of immature graft-infiltrating cells. Both animals also demonstrated donor-specific T cell hyporesponsiveness, as measured by MLR and cell-mediated lympholysis. The thymic grafts continued to develop despite the appearance of high levels of anti-donor specific cytotoxic IgG Abs. Thus, thymic tissue transplanted across an SLA class I barrier can engraft and support host thymopoiesis in euthymic miniature swine. The presence of the host thymus was required for engraftment. These data support the potential of thymic transplantation as part of a regimen to induce donor-specific tolerance to xenogeneic organ grafts.

Animals↗
PubMed1999

Intravascular ultrasound for evaluation of initial vessel patency and early outcome following directional coronary atherectomy.

Elastic recoil and thrombus formation may potentially occur following directional coronary atherectomy (DCA) confounding the assessment of late vascular remodeling. Since intravascular ultrasound (IVUS) data on early outcome of DCA is not available, we used IVUS to investigate whether elastic recoil or thrombus formation can affect early (4 hr) outcome. Quantitative coronary angiography (QCA) and IVUS were performed in high-grade coronary lesions in 32 consecutive patients before, immediately after, and 4 hr after DCA. Late clinical follow-up was obtained after a maximum interval of 2 years. Significant acute elastic recoil was observed by both IVUS (19%+/-14%) and QCA (19%+/-12%), but there was no further recoil after 4 hr. DCA reduced plaque area by 51%+/-13%, an effect that was stable after 4 hr, indicating the absence of relevant thrombus formation. Residual area stenosis by IVUS was not related to the occurrence of late clinical events (n = 8). Mechanical recoil or thrombus formation do not hamper initial lumen gain achieved by DCA. Although QCA significantly underestimated residual plaque burden after DCA when compared to IVUS, the degree of residual area stenosis did not identify patients suffering from cardiac events on follow-up.

Aged↗