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  • Germany  (13)
  • COILS  (4)
  • 1
    Keywords: SPECTRA ; CELLS ; EXPRESSION ; CELL ; COMBINATION ; Germany ; human ; PERFUSION ; PROTEIN ; PROTEINS ; SEQUENCE ; SIGNAL ; cell culture ; culture ; ACID ; FORM ; ASSAY ; PURIFICATION ; GOLGI-APPARATUS ; CHROMATOGRAPHY ; HIGH-LEVEL EXPRESSION ; CORE PROTEIN ; serine ; QUANTITIES ; AFFINITY ; PROTEOGLYCAN ; AFFINITY-CHROMATOGRAPHY ; BETA-D-XYLOSYLTRANSFERASE ; glycosyltransferase,proteoglycan,perfusion chromatography,insect cells ; HIGH-LEVEL ; JAR CHORIOCARCINOMA CELLS ; MOLECULAR-CLONING ; PERFUSION CHROMATOGRAPHY ; PROTEIN LINKAGE REGION ; SERUM XYLOSYLTRANSFERASE ; SYSTEMIC-SCLEROSIS ; UDP-D-XYLOSE
    Abstract: Human xylosyltransferase I (XT-I) catalyzes the transfer of xylose from UDP-xylose to consensus serine residues of proteoglycan core proteins. Expression of a soluble form of recombinant histidine-tagged XT-I (rXT-I-HIS) was accomplished at a high level with High Five/pCG255-1 insect cells in suspension culture. The recombinant protein was purified to homogeneity by a combination of heparin affinity chromatography and metal (Ni2+) chelate affinity chromatography. Using the modern technique of perfusion chromatography, a rapid procedure for purification of the rXT-I-HIS from insect cell culture supernatant was developed. The purified, biologically active enzyme was homogeneous on SIDS-PAGE, was detected with anti-XT-I-antibodies, and had the expected tryptic fragment mass spectrum. N-terminal amino acid sequencing demonstrated that the N-terminal signal sequence of the expressed protein was quantitatively cleaved. The total yield of the enzyme after purification was 18% and resulted in a specific XT-I activity of 7.9 mU/mg. The K-m of the enzyme for recombinant [Val(36) Val(38)](delta1),[Gly(92),Ile(94)](delta2) bikunin was 0.8 muM. About 5 rag purified enzyme could be obtained from 1 L cell culture supernatant. The availability of substantial quantities of active, homogeneous enzyme will be of help in future biochemical and biophysical characterization of XT-I and for the development of a immunological XT-I assay. (C) 2003 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 14680799
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  • 2
    Keywords: Germany ; IMAGES ; imaging ; HEART ; RESOLUTION ; TIME ; MR ; MRI ; sensitivity ; TRACKING ; MAGNETIC-RESONANCE ANGIOGRAPHY ; RECONSTRUCTION ; 2D ; MATRIX ; CATHETER TRACKING ; active device tracking ; interventional MRI ; intravascular catheters ; COILS ; SENSE ; CATHETER ; cardiac MRI ; GRAPPA ; interactive real-time parallel MRI ; TSENSE ; ACTIVE CATHETER TRACKING
    Abstract: In this work active MR catheter tracking with automatic slice alignment was combined with an autocalibrated parallel imaging technique. Using an optimized generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 2, we were able to reduce the acquisition time per image by 34%. To accelerate real-time GRAPPA image reconstruction, the coil sensitivities were updated only after slice reorientation. For a 2D trueFISP acquisition (160 x 256 matrix, 80% phase matrix, half Fourier acquisition, TR = 3.7 ms, GRAPPA factor = 2) real-time image reconstruction was achieved with up to six imaging coils. In a single animal experiment the method was used to steer a catheter from the vena cava through the beating heart into the pulmonary vasculature at an image update rate of about five images per second. Under all slice orientations, parallel image reconstruction was accomplished with only minor image artifacts, and the increased temporal resolution provided a sharp delineation of intracardial structures, such as the papillary muscle
    Type of Publication: Journal article published
    PubMed ID: 16683261
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  • 3
    Keywords: CELLS ; EXPRESSION ; Germany ; human ; CDNA CLONES ; GENE ; GENES ; GENOME ; HYBRIDIZATION ; PROTEIN ; PROTEINS ; transcription ; data mining ; radiation ; murine ; FAMILY ; MEMBER ; SEQUENCE ; TRANSPORT ; MOUSE ; IN-SITU ; YEAST ; MEMBRANE ; REQUIRES ; AAA family ; DATABASE ; DISPLAY ; endocytosis ; ENDOSOMAL TRAFFICKING ; FISH ; FUSION PROTEINS ; HUMAN GENOME ; INTRACELLULAR PROTEIN TRAFFICKING ; LATE-GOLGI ; MOUSE SKD1 ; MULTIVESICULAR BODY ; TRAFFICKING ; vacuolar protein sorting ; VPS4- paralogue
    Abstract: The VPS4 gene is a member of the AAA-family; it codes for an ATPase which is involved in lysosomal/endosomal membrane trafficking. VPS4 genes are present in virtually all eukaryotes. Exhaustive data mining of all available genomic databases from completely or partially sequenced organisms revealed the existence of up to three paralogues, VPS4a, -b, and -c. Whereas in the genome of lower eukaryotes like yeast only one VPS4 representative is present, we found that mammals harbour two paralogues, VPS4a and VPS4b. Most interestingly, the Fugu fish contains a third VPS4 paralogue (VPS4c). Sequence comparison of the three VPS4 paralogues indicates that the Fugu VPS4c displays sequence features intermediate between VPS4a and VPS4b. Using complete mammalian VPS4a and VPS4b cDNA clones as probes, genomic clones of both VPS4 paralogues in human and mouse were identified and sequenced. The chromosomal loci of all four VPS4 genes were determined by independent methods. A BLAST search of the human genome database with the human VPS4A sequence yielded a double match, most likely due to a faulty assembly of sequence contigs in the human draft sequence. Fluorescent in situ hybridization and radiation hybrid analyses demonstrated that human and mouse VPS4A/a and VPS4B/b are located on syntenic chromosomal regions. Northern blot and semi-quantitative reverse transcription analyses showed that mouse VPS4a and VPS4b are differentially expressed in different organs, suggesting that the two paralogues have developed different functional properties since their divergence. To investigate the subcellular distribution of the murine VPS4 paralogues, we transiently expressed various fluorescent VPS4 fusion proteins in mouse 3T3 cells. All tested VPS4 fusion proteins were found in the cytosol. Expression of dominant- negative mutant VPS4 fusion proteins led to their concentration in the perinuclear region. Co-expression of VPS4a-GFP and VPS4b-dsRed fusion proteins revealed a partial co-localization that was most prominent with mutant VPS4a and VPS4b proteins. A physical interaction between the mouse paralogues was also supported by two-hybrid analyses. (C) 2003 Elsevier Science B.V. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 12594041
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  • 4
    Keywords: Germany ; CT ; DENSITY ; TOOL ; GENE ; DIFFERENTIATION ; DOMAIN ; CONTRAST ; fibroblasts ; NUCLEI ; CHROMATIN ; IN-SITU HYBRIDIZATION ; LYMPHOCYTES ; FISH ; HUMAN GENOME ; MAMMALIAN-CELLS ; SPATIAL-ORGANIZATION ; TERRITORIES ; CHROMOSOME TERRITORIES ; ARCHITECTURE ; INTERPHASE NUCLEUS ; FUNCTIONAL IMPLICATIONS ; CELL-NUCLEI ; ORDER CHROMATIN ARRANGEMENTS
    Abstract: Studies of higher-order chromatin arrangements are an essential part of ongoing attempts to explore changes in epigenome structure and their functional implications during development and cell differentiation. However, the extent and cell-type-specificity of three-dimensional (3D) chromosome arrangements has remained controversial. In order to overcome technical limitations of previous studies, we have developed tools that allow the quantitative 3D positional mapping of all chromosomes simultaneously. We present unequivocal evidence for a probabilistic 3D order of prometaphase chromosomes, as well as of chromosome territories (CTs) in nuclei of quiescent (G0) and cycling ( early S-phase) human diploid fibroblasts ( 46, XY). Radial distance measurements showed a probabilistic, highly nonrandom correlation with chromosome size: small chromosomes - independently of their gene density - were distributed significantly closer to the center of the nucleus or prometaphase rosette, while large chromosomes were located closer to the nuclear or rosette rim. This arrangement was independently confirmed in both human fibroblast and amniotic fluid cell nuclei. Notably, these cell types exhibit flat-ellipsoidal cell nuclei, in contrast to the spherical nuclei of lymphocytes and several other human cell types, for which we and others previously demonstrated gene-density-correlated radial 3D CT arrangements. Modeling of 3D CT arrangements suggests that cell-type-specific differences in radial CT arrangements are not solely due to geometrical constraints that result from nuclear shape differences. We also found gene-density-correlated arrangements of higher-order chromatin shared by all human cell types studied so far. Chromatin domains, which are gene-poor, form a layer beneath the nuclear envelope, while gene-dense chromatin is enriched in the nuclear interior. We discuss the possible functional implications of this finding
    Type of Publication: Journal article published
    PubMed ID: 15839726
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  • 5
    Keywords: EXPRESSION ; Germany ; IN-VIVO ; MICROSCOPY ; liver ; RISK ; PROTEIN ; PROTEINS ; transcription ; DRUG ; METABOLISM ; FAMILY ; RAT ; RATS ; CONTRAST ; TRANSPORT ; RAT-LIVER ; resistance ; POLYPEPTIDE ; POLYMERASE-CHAIN-REACTION ; MULTIDRUG-RESISTANCE PROTEIN ; PHARMACOKINETICS ; rat liver ; MULTIDRUG-RESISTANCE ; MRP2 ; SUBSTRATE-SPECIFICITY ; ORGANIC ANION TRANSPORTER ; multidrug resistance ; INCREASE ; secretion ; polymerase chain reaction ; TRANSPORTER ; regulation ; POLYPEPTIDES ; FEMALE RATS ; GENDER ; EVENTS ; immunofluorescence ; multidrug resistance protein ; DEHYDROEPIANDROSTERONE-SULFATE ; MRP3 ; MRP ; CONSTITUTIVE ANDROSTANE RECEPTOR ; DHEA-S ; MRP FAMILY ; PREGNANE X-RECEPTOR ; SEX-DIFFERENCES
    Abstract: Background Sex differences in drug pharmacokinetics have been well recognized and gender has been considered a risk factor for adverse events to medications. The aim of this study was to investigate the effect of gender on the expression of hepatocellular transport proteins involved in uptake and secretion of organic anions in rat. Materials and methods Expression of the rat liver organic anion transporting polypeptides (Oatps) and multidrug resistance proteins (Mrps) was analysed by reverse transcription polymerase chain reaction (RT-PCR), immunoblot analysis and immunofluorescence microscopy in male and female rats. Regulation of these transport proteins in response to the steroid dehydroepiandrosterone (DHEA) was investigated. Results In untreated rats, protein expression significantly differed between genders being higher (Mrp2, Mrp3), comparable [Oatp1a1 (Oatp1); Oatp1b2 (Oatp4)] or lower [Oatp1a4 (Oatp2)] in female than in male rat. DHEA treatment over 3 days (100 mg d(-1)) led to a further increase in Mrp3 expression only in female rats. Mrp2 expression was not influenced by DHEA treatment. Oatp1a1 and Oatp1b2 were significantly down-regulated after DHEA treatment in both male and female rats. In contrast, Oatp1a4 was down-regulated in male rats only. Conclusions In rat, liver transport proteins of the Oatp and Mrp family are expressed and regulated in a gender-specific manner according to sexual differences in the hepatic metabolism of steroids and drugs. These findings may partly explain the well-known sex differences in hepatic handling of organic anions
    Type of Publication: Journal article published
    PubMed ID: 16178883
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  • 6
    Keywords: Germany ; imaging ; SYSTEM ; SYSTEMS ; RESOLUTION ; TIME ; MARKER ; MR ; SEQUENCE ; SEQUENCES ; SIGNAL ; SUSCEPTIBILITY ; FIELD ; MAGNETIC-RESONANCE ; ACQUISITION ; RELAXATION ; TRACKING ; BIOPSY ; RE ; INTERVENTIONAL DEVICES ; INFUSION ; ENHANCEMENT ; SIZE ; COILS ; technique ; VIEW ; RARE ; CATHETERS ; DEFT ; device localization ; fast MRI ; INNER VOLUME ; inner volume imaging ; local look (LoLo) ; percutaneous intervention ; WIRES
    Abstract: Percutaneous MR-guided interventions with needles require fast pulse sequences to image the needle trajectory with minimal susceptibility artifacts. Spin-echo pulse sequences are well suited for reducing artifact size; however, even with single-shot turbo spin-echo techniques, such as rapid acquisition with relaxation enhancement (RARE) or half-Fourier acquisition single-shot turbo spin-echo (HASTE), fast imaging remains challenging. In this work we present a HASTE pulse sequence that is combined with inner-volume excitation to reduce the scan time and limit the imaging field of view (FOV) to a small strip close to the needle trajectory (targeted-HASTE). To compensate for signal saturation from fast repeated acquisitions, a magnetization restore pulse (driven equilibrium Fourier transform (DEFT)) is used. The sequence is combined with dedicated active marker coils to measure the position and orientation of the needle so that the targeted-HASTE image slice is automatically repositioned. In an animal experiment the coils were attached to an MR-compatible robotic assistance system for MR-guided interventions. Needle insertion and infusion via the needle could be visualized with a temporal resolution of 1 s, and the needle tip could be localized even in the presence of a stainless steel mandrel
    Type of Publication: Journal article published
    PubMed ID: 16795081
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  • 7
    Keywords: SIMULATIONS ; COMBINATION ; Germany ; ALGORITHM ; SYSTEM ; SYSTEMS ; MARKER ; SIMULATION ; MR ; MRI ; SIGNAL ; LOCALIZATION ; PARAMETERS ; sensitivity ; TRACKING ; EXTENSION ; interventional MRI ; analysis ; correlation ; SIGNALS ; phantom ; German ; PRECISION ; INSTRUMENTS ; MR-guided interventions ; percutaneous interventions ; PHASE CORRELATION ; phase-only cross correlation ; robotic assistance system ; SUBPIXEL REGISTRATION
    Abstract: The localization of passive marker systems in interventional MRI is necessary to monitor the position and orientation of medical instruments that do not emit an MR signal. In this work an algorithm is presented that automatically detects a given marker system in an MR image with a precision better than one pixel. Therefore, a combination of a phase-only cross correlation algorithm with a subsequent center-of-mass analysis is utilized. The algorithm was evaluated in simulations and phantom experiments with respect to precision, noise sensitivity as well as the influence of unwanted signal amplitudes. Above a signal-to-noise ratio (SNR) of 4.5 a localization precision significantly better than the pixel dimension could be achieved. For SNR values of 6 and more the influence of unwanted signals on the localization could not be detected in the simulations. In phantom experiments the predicted precision of the marker localization could he realized which results for typical measurement parameters in a maximal deviation of the needle tip in an MR-guided needle injection of 0.6 mm
    Type of Publication: Journal article published
    PubMed ID: 17879815
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  • 8
    Keywords: Germany ; ALGORITHM ; IMAGES ; imaging ; HEART ; TIME ; INTERVENTION ; MRI ; SIGNAL ; MAGNETIC-RESONANCE ; RATES ; SELECTION ; TRACKING ; RECONSTRUCTION ; SUBSET ; CATHETER TRACKING ; INCREASE ; active device tracking ; interactive real-time MRI ; interventional MRI ; intravascular catheters ; COILS ; CATHETER ; ACTIVE CATHETER TRACKING ; image reconstruction optimization ; PHASED-ARRAY
    Abstract: MR-guided intravascular interventions require image update rates of up to 10 images per second, which can be achieved using parallel imaging. However, parallel imaging requires many coil elements, which increases reconstruction times and thus compromises real-time image reconstruction. In this study a dynamic coil selection (DCS) algorithm is presented that selects a subset of receive coils to reduce image reconstruction times. The center-of-sensitivity coordinates and the relative signal intensities are determined for each coil in a prescan. During the intervention m coils are selected for reconstruction using a coil ranking based on the distance to the current slice or catheter position. In a phantom experiment for m = 6, an optimal signal-to-background ratio (SBR) was achieved and foldover artifacts were avoided. In three animal experiments involving catheter manipulation in the aorta and the right heart chamber, the anatomy was successfully visualized at frame rates of about 5 Hz using active catheter tracking
    Type of Publication: Journal article published
    PubMed ID: 17029224
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  • 9
    Keywords: SURVIVAL ; BLOOD ; CELL ; Germany ; THERAPY ; DEATH ; DISEASE ; PATIENT ; CYCLE ; treatment ; LYMPHOMA ; chemotherapy ; PROGNOSTIC-FACTORS ; BONE-MARROW-TRANSPLANTATION ; CYCLOPHOSPHAMIDE ; RANDOMIZED TRIAL ; Hodgkin's lymphoma ; ifosfamide ; ETOPOSIDE ; PHASE-II ; NON-HODGKINS-LYMPHOMA ; HIGH-DOSE CHEMOTHERAPY ; RE ; analysis ; SINGLE-CENTER ; PROGENITOR-CELL ; CONVENTIONAL CHEMOTHERAPY ; 2ND-LINE THERAPY ; aggressive non-Hodgkin's lymphoma ; ARA-C ; POOR-RISK ; salvage treatment
    Abstract: High-dose chemotherapy (HD-CT) with autologous stem cell transplantation is considered to be the treatment of choice for relapsed high-grade non-Hodgkin's lymphoma (NHL) and Hodgkin's lymphoma (HL) patients, but the optimal treatment has not yet been defined. We evaluated a salvage treatment regimen consisting of conventional cycles with ifosfamide, etoposide, cytarabine, and dexamethasone (IVAD) followed by two cycles of HD-CT consisting of cyclophosphamide, melphalan, and etoposide (CMV) with autologous stem cell support in patients with relapsed or refractory NHL (n = 59) and HL (n = 16). Response to IVAD was complete remission (CR) in 16 patients (21%), partial remission (PR) in 39 patients (52%), stable disease (SD) in 18 patients (24%), and progressive disease (PD) in two patients (2.7%). Of 70 patients treated with HD-CT, 41 patients (59%) showed a CR, 20 patients a PR (29%), eight patients a SD (11%), and one patient a PD (1.4%). The 5-yr overall survival for the entire group of patients was 29%, and for patients with NHL and HL 25%, and 38%, respectively. The respective event-free survival probabilities at 5 yr were 22%, 16%, and 31%. Seven treatment-related deaths due to septicemia (three), cardiac arrhythmia (one), pneumonia (one), pneumonitis (one), and toxic epidermal necrolysis (one) were observed. In multivariate analysis, an International Prognostic Index of 〉= 2 and resistant disease to first-line chemotherapy were poor independent prognostic factors for the subgroup of patients with NHL. In conclusion, these results indicate that IVAD/CMV is feasible as a salvage therapy for lymphoma patients. This treatment is currently evaluated with the addition of rituximab
    Type of Publication: Journal article published
    PubMed ID: 17313557
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  • 10
    Keywords: CANCER ; tumor ; Germany ; neoplasms ; DIAGNOSIS ; imaging ; DISEASE ; TUMORS ; computed tomography ; INDUCTION ; REGION ; RESECTION ; tomography ; STOMACH ; COMPUTED-TOMOGRAPHY ; BILE ; CHOLESTASIS ; stroma ; Type ; Cutaneous ; cardiac ; gastrointestinal stromatumor (GIST) ; neurofibromatosis Recklinghausen ; obstructive jaundice ; Takotsubo cardiomyopathy
    Abstract: In this case report we present a 61-year-old patient with obstructive jaundice. Bile duct obstruction was caused by a tumor at the duodenal papilla and bile flow was restored by a plastic stent. Using endoscopic ultrasound and computed tomography imaging two additional tumors of the same morphology were found in the stomach wall and the pelvic region suggesting a multilocular gastrointestinal stroma tumor (GIST). Diagnosis of GIST was confirmed cytologically from the gastric lesion. Based on typical cutaneous manifestations (cafe-au-lait spots, several tiny dermal neurofibromata and Lisch nodules in the iris), a thus far unidentified neurofibromatosis type I was diagnosed which is known to promote multilocular GIST formation. Tumor resection failed because of cardiac decompensation due to a Takotsubo cardiomyopathy during induction of anesthesia. The patient has been started on imatinib instead and shows so far a stable disease over 6 months
    Type of Publication: Journal article published
    PubMed ID: 20352594
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