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Holm J. Effect of tetraethylammonium and N 1 -methylnicotinamide on the uptake of decamethonium and carbamoylcholine by slices of mouse kidney. ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 30:89-96. [PMID: 4256474 DOI: 10.1111/j.1600-0773.1971.tb00637.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Willumsen N, Holm J, Christensen L, Würtzen P, Lund K. Characterization of Allergic Patients' Serum IgE Composition by Facilitated Allergen Presentation. J Allergy Clin Immunol 2009. [DOI: 10.1016/j.jaci.2008.12.464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Volkmann E, Falk A, Holm J, Philipson B, Risberg B, Volkmann R. Effect of Varicose Vein Surgery on Venous Reflux Scoring and Plethysmographic Assessment of Venous Function. Eur J Vasc Endovasc Surg 2008; 36:731-7. [DOI: 10.1016/j.ejvs.2008.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 06/08/2008] [Indexed: 11/29/2022]
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Christensen LH, Holm J, Lund G, Riise E, Lund K. Several distinct properties of the IgE repertoire determine effector cell degranulation in response to allergen challenge. J Allergy Clin Immunol 2008; 122:298-304. [DOI: 10.1016/j.jaci.2008.05.026] [Citation(s) in RCA: 169] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2008] [Revised: 05/16/2008] [Accepted: 05/19/2008] [Indexed: 10/21/2022]
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Biörklund M, Holm J, Önning G. Serum Lipids and Postprandial Glucose and Insulin Levels in Hyperlipidemic Subjects after Consumption of an Oat β-Glucan-Containing Ready Meal. ANNALS OF NUTRITION AND METABOLISM 2008; 52:83-90. [DOI: 10.1159/000121281] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 08/09/2006] [Indexed: 11/19/2022]
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Würtzen PA, Lund L, Lund G, Holm J, Millner A, Henmar H. Chemical Modification of Birch Allergen Extract Leads to a Reduction in Allergenicity as well as Immunogenicity. Int Arch Allergy Immunol 2007; 144:287-95. [PMID: 17641548 DOI: 10.1159/000106317] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 04/19/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In Europe, specific immunotherapy is currently conducted with vaccines containing allergen preparations based on intact extracts. In addition to this, chemically modified allergen extracts (allergoids) are used for specific allergy treatment. Reduced allergenicity and thereby reduced risk of side effects in combination with retained ability to activate T cells and induce protective allergen-specific antibody responses has been claimed for allergoids. In the current study, we compared intact allergen extracts and allergoids with respect to allergenicity and immunogenicity. METHODS The immunological response to birch allergen extract, alum-adsorbed extract, birch allergoid and alum-adsorbed allergoid was investigated in vitro in human basophil histamine release assay and by stimulation of human allergen-specific T cell lines. In vivo, Bet v 1-specific IgG titers in mice were determined after repetitive immunizations. RESULTS In all patients tested (n = 8), allergoid stimulations led to reduced histamine release compared to the intact allergen extract. However, the allergoid preparations were not recognized by Bet v 1-specific T cell lines (n = 7), which responded strongly to the intact allergen extract. Mouse immunizations showed a clearly reduced IgG induction by allergoids and a strongly potentiating effect of the alum adjuvant. Optimal IgG titers were obtained after 3 immunizations with intact allergen extracts, while 5 immunizations were needed to obtain maximal response to the allergoid. CONCLUSION The reduced histamine release observed for allergoid preparations may be at the expense of immunological efficacy because the chemical modifications lead to a clear reduction in T cell activation and the ability to induce allergen-specific IgG antibody responses.
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Holm J, Christensen L, Skovsgaard J, Wurtzen P, Lund K. Role Of Inhibitory Antibodies For The Prevention Of IgE-allergen Complex Formation/CD-23 Antigen Uptake: Impact Of Antibody Affinity And Clonality Using Defined Ratios Of Recombinant IgE, IgG And Der p 2. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.12.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Garnaes J, Hansen PE, Agersnap N, Holm J, Borsetto F, Kühle A. Profiles of a high-aspect-ratio grating determined by spectroscopic scatterometry and atomic-force microscopy. APPLIED OPTICS 2006; 45:3201-12. [PMID: 16676023 DOI: 10.1364/ao.45.003201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The new and fast scatterometry method called optical diffraction microscopy is compared with atomic-force microscopy by use of cross-section scanning-electron microscope images as references. The sample is a high-aspect-ratio grating with a period of approximately 1000 nm. To allow the atomic-force microscope to track all parts of the grating profile, the grating is investigated at different tilt angles. The measured quantities of the profile include sidewall angle gamma (approximately 90 degrees), groove height h (approximately 2000 nm), and degree of filling f (approximately 40%). The two methods, which respond to quite different material properties, give consistent results within standard uncertainties of u(gamma)</=0.8 degrees , u(h)</=15 nm, and u(f)</=1%.
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Holm J, Olla P, Moura D, Warhaut M. Creating architectural approaches to knowledge management: an example from the space industry. JOURNAL OF KNOWLEDGE MANAGEMENT 2006. [DOI: 10.1108/13673270610656610] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Lund G, Jacobi H, Holm J, Lund K. Protocol for in vitro Desensitization of Human Basophils that Mimics the Up Dosing Approach used in SCIT - Monitored Measuring CD63 and CD203c Activation Markers. J Allergy Clin Immunol 2006. [DOI: 10.1016/j.jaci.2005.12.284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Christensen L, Holm J, Skovsgaard J, Lund K. The Significance of Clonality and Affinity of Individual Allergen-Specific IgE Antibodies for the Activation of Human Basophils. J Allergy Clin Immunol 2006. [DOI: 10.1016/j.jaci.2005.12.1224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Reed KM, Holm J, Morisson M, Leroux S, Vignal A. Assignment of non-informative turkey genetic markers through comparative approaches. Cytogenet Genome Res 2005; 109:527-32. [PMID: 15905649 DOI: 10.1159/000084214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 09/08/2004] [Indexed: 11/19/2022] Open
Abstract
Molecular markers such as microsatellites, provide genetic signposts for navigating genomes. In general, genetic markers that are monomorphic or non-informative in mapping populations typically remain unmapped and as such are less likely to be included in future studies. The use of hybrid cell panels and in silico mapping via whole genome sequences allow for positional mapping of non-segregating markers. This study utilizes the INRA ChickRH6 whole-genome radiation hybrid panel and chicken whole-genome shotgun sequence to map microsatellite markers from the turkey (Meleagris gallopavo). Thirty-three of the 41 markers typed on the RH panel had significant linkage to at least one other marker and 83 of 100 sequences returned significant BLAST similarities. Positioning of these markers provides additional sequence tagged sites in the turkey genome and increases the potential use of these markers for future genetic studies.
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Herlitz J, Holm J, Peterson M, Karlson BW, Evander MH, Erhardt L. Factors associated with development of stroke long-term after myocardial infarction: experiences from the LoWASA trial. J Intern Med 2005; 257:201-7. [PMID: 15656879 DOI: 10.1111/j.1365-2796.2004.01433.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To describe factors associated with the development of stroke during long-term follow-up after acute myocardial infarction (AMI) in the LoWASA trial. PATIENTS Patients who had been hospitalized for AMI were randomized within 42 days to receive either warfarin 1.25 mg plus aspirin 75 mg daily or aspirin 75 mg alone. DESIGN The study was performed according to the probe design, that is open treatment and blinded end-point evaluation. SETTING The study was performed in 31 hospitals in Sweden. The mean follow-up time was 5.0 years with a range of 1.7-6.7 years. RESULTS In all, 3300 patients were randomized in the trial, of which 194 (5.9%) developed stroke (4.2% nonhaemorrhagic, 0.5% haemorrhagic and 1.3% uncertain. The following factors appeared as independent predictors for an increased risk of stroke: age, hazard ratio and 95% confidence interval (1.07; 1.05-1.08), a history of diabetes mellitus (2.4; 1.8-3.4), a history of stroke (2.3; 1.5-3.5), a history of hypertension (2.0; 1.5-2.7) and a history of smoking (1.5;1.1-2.0). Most of these factors were also predictors of a nonhaemorrhagic stroke whereas no predictor of haemorrhagic stroke was found. CONCLUSION Risk indicators for stroke long-term after AMI were increasing age, a history of either diabetes mellitus, stroke, hypertension or smoking.
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Holm J, Gajhede M, Ferreras M, Henriksen A, Ipsen H, Larsen JN, Lund L, Jacobi H, Millner A, Würtzen PA, Spangfort MD. Allergy Vaccine Engineering: Epitope Modulation of Recombinant Bet v 1 Reduces IgE Binding but Retains Protein Folding Pattern for Induction of Protective Blocking-Antibody Responses. THE JOURNAL OF IMMUNOLOGY 2004; 173:5258-67. [PMID: 15470071 DOI: 10.4049/jimmunol.173.8.5258] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human type 1 immediate allergic response symptoms are caused by mediator release from basophils and mast cells. This event is triggered by allergens aggregating preformed IgE Abs bound to the high-affinity receptor (FcepsilonRI) on these cells. Thus, the allergen/IgE interaction is crucial for the cascade leading to the allergic and anaphylactic response. Two genetically engineered forms of the white birch pollen major allergen Bet v 1 with point mutations directed at molecular surfaces have been characterized. Four and nine point mutations led to a significant reduction of the binding to human serum IgE, suggesting a mutation-induced distortion of IgE-binding B cell epitopes. In addition, the mutated allergens showed a decrease in anaphylactic potential, because histamine release from human basophils was significantly reduced. Retained alpha-carbon backbone folding pattern of the mutated allergens was indicated by x-ray diffraction analysis and circular dichroism spectroscopy. The rBet v 1 mutants were able to induce proliferation of T cell lines derived from birch pollen allergic patients. The stimulation indices were similar to the indices of nonmutated rBet v 1 and natural Bet v 1 purified from birch pollen. The ability of anti-rBet v 1 mutant specific mouse IgG serum to block binding of human serum IgE to rBet v 1 demonstrates that the engineered rBet v 1 mutants are able to induce Abs reactive with nonmodified Bet v 1. rBet v 1 mutants may constitute vaccine candidates with improved efficacy/safety profiles for safer allergy vaccination.
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Mogensen JE, Ipsen H, Holm J, Otzen DE. Elimination of a misfolded folding intermediate by a single point mutation. Biochemistry 2004; 43:3357-67. [PMID: 15035607 DOI: 10.1021/bi0358622] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present an analysis of the folding behavior of the 159-residue major birch pollen allergen Bet v 1. The protein contains a water-filled channel running through it. Consequently, the protein has a hydrophobic shell, rather than a hydrophobic core. During the folding of the protein from either the urea-, pH-, or SDS-denatured state, Bet v 1 transiently populates a partially folded intermediate state. This state appears to be misfolded, since it has to unfold at least partially to fold to the native state. The misfolded intermediate is not, however, a result of the water-filled channel in Bet v 1. The intermediate completely disappears in the mutant Tyr --> Trp120, in which the channel is still present. Tyr120 appears to behave as a "negative gatekeeper" which attenuates efficient folding. The close structural homologue, the apple allergen Mal d 1, also folds without any detectable folding intermediates. However, the position of the transition state on the reaction coordinate, which is a measure of its overall compactness relative to the denatured and native states, is reduced dramatically from ca. 0.9 in Bet v 1 to around 0.5 in Mal d 1. We suggest that this large shift in the transition state structure is partly due to different local helix propensities. Given that individual mutations can have such large effects on folding, one should not a priori expect structurally homologous proteins to fold by the same mechanism.
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Ramaekers VT, Hansen SI, Holm J, Opladen T, Senderek J, Häusler M, Heimann G, Fowler B, Maiwald R, Blau N. Reduced folate transport to the CNS in female Rett patients. Neurology 2003; 61:506-15. [PMID: 12939425 DOI: 10.1212/01.wnl.0000078939.64774.1b] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Previous CSF studies in Rett syndrome suggest reduced turnover of the biogenic monoamines serotonin and dopamine. Because diminished turnover may result from CNS folate depletion, the authors studied transport of folate across the blood-brain barrier. METHODS In four patients with Rett syndrome, the authors measured CSF values of 5-methyltetrahydrofolate (5MTHF), biogenic monoamine end-metabolites, and pterins together with serum and red blood cell folate. In CSF, the overall folate binding capacity by the two soluble folate-binding proteins FBP1 and FBP2 (sFBP) was measured using a radioligand binding method for H3-labeled folate. A specific immunoreactive test (ELISA) detected sFBP1, which normally contributes to 30 to 35% of the total folate binding capacity. Genetic analysis included DNA sequencing of the MECP2, FBP1, and FBP2 genes. Empirical treatment with oral folinic acid was evaluated. RESULTS Two patients without and two with mutations of the MECP2 gene had normal values for red blood cell folate, serum folate, homocysteine, and methionine. In CSF, all patients had low values for 5MTHF, neopterin, and the serotonin end-metabolite 5-hydroxyindoleacetic acid (5-HIAA). Genetic analysis of FBP1 and FBP2 genes had normal results. Compared to controls, patients with Rett syndrome had normal immunoreactive sFBP1 in CSF, whereas the total folate binding capacity was disproportionately lowered. Empirical treatment with oral folinic acid normalized 5-MHTF and 5-HIAA levels in CSF, and led to partial clinical improvement. CONCLUSION Irrespective of the MECP2 genotype, 5MTHF transfer to the CNS is reduced in Rett syndrome. Folinic acid supplementation restores 5MTHF levels and serotoninergic turnover. The lowered folate binding capacity of FBP is not explained by a defect of the FBP1 or FBP2 gene, but most likely occurs as a secondary phenomenon in Rett syndrome.
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von Eyben FE, Mouritsen E, Holm J, Montvilas P, Dimcevski G, Suciu G, Helleberg I, Kristensen L, von Eyben R. Intra-abdominal obesity and metabolic risk factors: a study of young adults. Int J Obes (Lond) 2003; 27:941-9. [PMID: 12861235 DOI: 10.1038/sj.ijo.0802309] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE To assess the relative importance of the extent and regional distribution of fat for metabolic risk factors in young adults. DESIGN Cross-sectional study of findings from a hospital-based case-control study. SUBJECTS A total of 46 adult Danish Caucasian patients (40 men and six women, aged 34-54 y). Of these, 22 had had non fatal acute myocardial infarction before 41 y of age and 24 were age- and gender-matched controls without coronary heart disease. MEASUREMENTS Four measurements of fat: body mass index (BMI, kg/m(2)), body fat percentage measured using a dual energy X-ray absorptiometry (DEXA) scanner, waist/hip circumference ratio (WHR), and intra-abdominal adipose tissue area measured using computed tomography (CT) scanning, and eight metabolic risk factors: systolic and diastolic blood pressure, HbA(1c) percentage, fasting concentrations of capillary whole blood glucose, high-density lipoprotein (HDL) cholesterol, serum triglyceride, plasma plasminogen activator inhibitor 1 (PAI-1), and urinary albumin:creatinine excretion ratio. RESULTS Of 46 participants, 10 were obese (BMI >30 kg/m(2)), 12 were abdominally obese (WHR >0.90 for men and >0.85 for women), and 20 were intra-abdominally obese (intra-abdominal adipose tissue area >135 cm(2)). Men had a higher intra-abdominal adipose tissue area than women (P=0.0053, Mann-Whitney U-test). In multiple regression analyses of the four fat variables, only intra-abdominal adipose tissue area significantly predicted the levels of six metabolic risk factors: systolic blood pressure, diastolic blood pressure, fasting concentrations of capillary whole blood glucose, serum HDL cholesterol, serum triglyceride, and PAI-1. The intra-abdominal adipose tissue area had a linear relation with the six metabolic risk factors. CONCLUSIONS For young individuals, intra-abdominal fat is the important component of the body fat for six of the eight metabolic risk factors. Intra-abdominal fat might contribute to that most patients with acute myocardial infarction at a young age are men.
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Zachrisson H, Blomstrand C, Holm J, Mattsson E, Volkmann R. Changes in middle cerebral artery blood flow after carotid endarterectomy as monitored by transcranial Doppler. J Vasc Surg 2002; 36:285-90. [PMID: 12170208 DOI: 10.1067/mva.2002.125843] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE By using transcranial Doppler (TCD) it is possible to measure blood flow velocities within the circle of Willis. In this study, TCD was performed before and after carotid endarterectomy (CEA) with the aim to describe cerebral hemodynamics after normalization of the carotid artery blood flow. METHODS Thirty CEA patients were consecutively entered into the TCD study, whereas 15 patients were referred for postoperative TCD for various clinical reasons. All 45 patients were investigated by using TCD: first preoperatively, then during the first few days after CEA before discharge from the hospital, and finally 3 to 12 months later. In addition, all patients underwent duplex investigation of the internal carotid artery the day before surgery and 3 months postoperatively. For the analysis, the patients were divided into two groups, one with (S-group), suspected postoperative neurologic complications/symptoms and another one without (C-group). Six patients were assigned to the S-group and 37 to the C-group, the latter including two patients who underwent bilateral CEAs. RESULTS In the whole study group,a significant postoperative increase in systolic flow velocity was recorded bilaterally in the middle cerebral artery (MCA) as measured some days after surgery. The patients in the S-group showed high blood flow velocities mainly in the MCA on the ipsilateral side. A contralateral flow velocity increase did not occur in patients with very severe contralateral stenosis or occlusion (n = 9) if the late follow-up investigation was chosen as a reference value. Twenty patients in the C-group formed a subgroup with high blood pressure and/or headache postoperatively (CB-group) The other 19 patients were referred to as the CA-group. The CB- and S-groups showed more pronounced vessel disease in internal carotid artery on the contralateral side combined with lower collateral capacity in the circle of Willis compared to the CA-group. In the S-group the mean +/- standard deviation peak systolic velocity in ipsilateral MCA increased from a preoperative value of 0.71 +/- 0.22 m/sec to 2.23 +/- 0.72 m/sec (P <.005). In the CB-group, we observed a bilateral MCA blood flow velocity increase from 0.72 +/- 0.18 to 1.35 +/- 0.56 m/sec (P <.0001) on the ipsilateral side and from 0.82 +/- 0.37 to 1.28 +/- 0.66 m/sec (P < 0.001) on the contralateral side. In the CA-group, we observed minor bilateral blood flow velocity increases in the MCA, from 0.79 +/- 0.25 m/sec to 1.03 +/- 0.33 m/sec on the ipsilateral (P <.001) and from 0.70 +/- 0.17 m/sec to 0.93 +/- 0.26 m/sec on the contralateral side (P <.005). At the follow-up 3 to 12 months after surgery, the MCA flow velocities had returned to normal. CONCLUSIONS Soon after surgery, blood flow velocity increases often bilaterally in the MCA. However a contralateral flow velocity increase did not occur in patients with very severe contralateral stenosis or occlusion if the late follow-up investigation was chosen as a reference value. The clinical significance of bilateral flow velocity increases is uncertain, but very high blood flow velocities might be a signal for cerebrovascular hyperperfusion. In those patients, increased postoperative surveillance is recommended.
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Millner A, Würtzen PA, Holm J, Heinig JH, Jacobi HH. Comparable T-cell activation induced by natural and recombinant Bet v 1. J Allergy Clin Immunol 2002. [DOI: 10.1016/s0091-6749(02)82106-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Larsen JN, Haugel-Nielsen J, Heinig JH, Holm J, Ipsen H, Jacobi HH, Würtzen PA, Spangfort MD. Differences in Bet v 1 epitope specificies of individual patients' IgE revealed by analysis of cross-reactivity between group 1 major allergens from birch and apple. J Allergy Clin Immunol 2002. [DOI: 10.1016/s0091-6749(02)81620-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Engesgaard P, Holm J, Jensen K, Henze M, Albrechtsen H. Development of preferential flow in bioclogging of porous media. COMPUTATIONAL METHODS IN WATER RESOURCES, PROCEEDINGS OF THE XIVTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL METHODS IN WATER RESOURCES (CMWR XIV) 2002. [DOI: 10.1016/s0167-5648(02)80144-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Holm J, Hansen SI. Binding of radiolabeled folate and 5-methyltetrahydrofolate to cow's milk folate binding protein at pH 7.4 and 5.0. Relationship to concentration and polymerization equilibrium of the purified protein. Biosci Rep 2001; 21:733-43. [PMID: 12166823 DOI: 10.1023/a:1015576522416] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Binding of folate (pteroylglutamate) and 5-methyltetrahydrofolate, the major endogenous form of folate, to folate binding protein purified from cow's milk was studied at 7 degrees C to avoid degradation of 5-methyltetrahydrofolate. Both folates dissociate rapidly from the protein at pH 3.5, but extremely slowly at pH 7.4, most likely due to drastic changes in protein conformation occurring after folate binding. Dissociation of 5-methyltetrahydrofolate showed no increase at 37 degrees C suggesting that protein-bound-5-methyltetrahydrofolate is protected against degradation. Binding displayed two characteristics, positive cooperativity and a binding affinity that increased with decreasing concentrations of the protein. The binding affinity of folate was somewhat greater than that of 5-methyl tetrahydrofolate, in particular at pH 5.0. Ligand-bound protein exhibited concentration-dependent polymerization (8-mers formed at 13 microM) at pH 7.4. At pH 5.0, only folate-bound forms showed noticeable polymerization. The fact that folate at pH 5.0 surpasses 5-methyltetrahydrofolate both with regard to binding affinity and ability to induce polymerization suggests that ligand binding is associated with conformational changes of the protein which favor polymerization.
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Holm J, Hansen SI. Effect of hydrogen ion concentration and buffer composition on ligand binding characteristics and polymerization of cow's milk folate binding protein. Biosci Rep 2001; 21:745-53. [PMID: 12166824 DOI: 10.1023/a:1015528606487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ligand binding and aggregation behavior of cow's milk folate binding protein depends on hydrogen ion concentration and buffer composition. At pH 5.0, the protein polymerizes in Tris-HCl subsequent to ligand binding. No polymerization occurs in acetate, and binding is markedly weaker in acetate or citrate buffers as compared to Tris-HCl. Polymerization of ligand-bound protein was far more pronounced at pH 7.4 as compared to pH 5.0 regardless of buffer composition. Binding affinity increased with decreasing concentration of protein both at pH 7.4 and 5.0. At pH 5.0 this effect seemed to level off at a protein concentration of 10(-6) M which is 100-1000 fold higher than at pH 7.4. The data can be interpreted in terms of complex models for ligand binding systems polymerizing both in the absence or presence of ligand (pH 7.4) as well as only subsequent to ligand binding (pH 5.0).
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Abstract
INTRODUCTION The increasing amount of clinical data, intensified interest of patients in medical information, medical quality management and the recent cost explosion in health care systems have forced medical institutions to improve their strategy in handling medical data. In the orthopedic department (3,600 surgeries, 75 beds, 14,000 consultations) software application for comprehensive patient data management has been developed. METHOD When implementing the electronic patient history following criteria were evaluated: 1. software evaluation, 2. implementation, 3. work flow, 4. data security/system stability. RESULTS In the first phase the functional character was defined. Implementation required 3 months after parametrization. The expense amounted to 130,000 DM (30 clients). The training requirements were one afternoon for the secretaries and a 2-h session for the residents. The access speed on medically relevant data averaged under 3 s. The average saving in working hours was approximately 5 h/week for the secretaries and 4 h/week for the residents. The saving in paper amounted to 36,000 sheets/year. In 3 operational years there were 3 server breakdowns. CONCLUSIONS Evaluation of the saving on working hours showed that such a system can amortize within a year. The latest improvements in hardware and software technology made the electronic medical record with integrated quality-control practicable without massive expenditure. The system supplies an extensive platform of information for patient treatment and an instrument to evaluate the efficiency of therapy strategies independent of the clinical field.
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