Mark Oliver Wielpütz

Publications

• 3.73

  Impact points

  Imaging Lung Perfusion.

  Susan Roberta Hopkins, Mark O Wielpütz, Hans-Ulrich Kauczor

  Journal of applied physiology (Bethesda, Md. : 1985). 05/2012;

  From the first measurements of the distribution of pulmonary blood flow using radioactive tracers by West and colleagues, allowing gravitational differences in pulmonary blood flow to be described (94), the imaging of pulmonary blood flow has made considerable progress. The researcher employing mode... [more] From the first measurements of the distribution of pulmonary blood flow using radioactive tracers by West and colleagues, allowing gravitational differences in pulmonary blood flow to be described (94), the imaging of pulmonary blood flow has made considerable progress. The researcher employing modern imaging techniques now has the choice of several techniques including magnetic resonance imaging (MRI), computerized tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT). These techniques differ in several important ways: the resolution of the measurement, the type of contrast or tag used to image flow, and the amount of ionizing radiation associated with each measurement. In addition the techniques vary in what is actually measured, whether it is capillary perfusion such as with PET and SPECT, or larger vessel information in addition to capillary perfusion such as with MRI and CT. Combined, these issues affect quantification and interpretation of data as well as the type of experiments possible using different techniques. The goal of this review is to give an overview of the techniques most commonly in use for physiological experiments along with the issues unique to each technique.
• 1.42

  Impact points

  Computed tomographic imaging of the airways in COPD and asthma.

  Hans-Ulrich Kauczor, Mark O Wielpütz, Michael Owsijewitsch, Julia Ley-Zaporozhan

  Journal of thoracic imaging. 11/2011; 26(4):290-300.

  Computed tomography (CT) is the modality of choice for imaging the airways. Volumetric data sets with isotropic spatial resolution based on multidetector thin-section CT with overlapping reconstruction should be used. Chronic obstructive pulmonary disease and asthma are the 2 most common disease ent... [more] Computed tomography (CT) is the modality of choice for imaging the airways. Volumetric data sets with isotropic spatial resolution based on multidetector thin-section CT with overlapping reconstruction should be used. Chronic obstructive pulmonary disease and asthma are the 2 most common disease entities that are defined by airflow obstruction. The morphologic correlates of airway changes are dilation of the lumen, thickening of the wall, visibility of small airways due to mucus or edema, air trapping, hypoxic vasoconstriction, and collapsibility. To assess air trapping, additional expiratory low-dose scans are recommended. In clinical routine, these findings are visually assessed and should be routinely reported. However, the interobserver variability is high, and there is a clear need for objective software-based measurements. The development of such tools is challenging, and they are just becoming available on a broader scale. Novel techniques based on dual-energy CT aim to measure iodine distribution maps to assess pulmonary perfusion as well as the distribution of inhaled xenon gas to assess the distribution and time course of pulmonary ventilation. However, these techniques are still being investigated in clinical studies. This review will provide an overview of CT for the diagnosis of chronic obstructive pulmonary disease and asthma, its role in phenotyping these diseases, and the measurement of disease severity and functional compromise.
• 5.53

  Impact points

  In vivo monitoring of cystic fibrosis-like lung disease in mice by volumetric computed tomography.

  M O Wielpütz, M Eichinger, Z Zhou, K Leotta, S Hirtz, S H Bartling, W Semmler, H-U Kauczor, M Puderbach, M A Mall

  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 04/2011; 38(5):1060-70.

  The onset and spontaneous development of cystic fibrosis (CF) lung disease remain poorly understood. In the present study, we used volumetric computed tomography (VCT) as a new method for longitudinal in vivo monitoring of early lesions and disease progression in CF-like lung disease in β-epithelial... [more] The onset and spontaneous development of cystic fibrosis (CF) lung disease remain poorly understood. In the present study, we used volumetric computed tomography (VCT) as a new method for longitudinal in vivo monitoring of early lesions and disease progression in CF-like lung disease in β-epithelial Na(+) channel (ENaC)-transgenic (TG) mice. Using a VCT scanner prototype (80 kV, 50 mA·s, scan time 19 s and spatial resolution 200 μm), βENaC-TG mice and wild-type (WT) littermates were examined longitudinally at 10 time-points from neonatal to adult ages, and VCT images were assessed by qualitative and quantitative morphological parameters. We demonstrate that VCT detected early-onset airway mucus obstruction, diffuse infiltrates, atelectasis and air trapping as characteristic abnormalities in βENaC-TG mice. Furthermore, we show that early tracheal mucus obstruction predicted mortality in βENaC-TG mice and that the density of lung parenchyma was significantly reduced at all time-points in βENaC-TG compared with WT mice (median ± sem -558 ± 8 HU in WT versus -686 ± 16 HU in βENaC-TG at 6 weeks of age; p < 0.005). Our study demonstrates that VCT is a sensitive, noninvasive technique for early detection and longitudinal monitoring of morphological abnormalities of CF-like lung disease in mice, and may thus provide a useful tool for pre-clinical in vivo evaluation of novel treatment strategies for CF.
• 2.65

  Impact points

  Morphologic and functional scoring of cystic fibrosis lung disease using MRI.

  Monika Eichinger, Daiva-Elzbieta Optazaite, Annette Kopp-Schneider, Christian Hintze, Jürgen Biederer, Anne Niemann, Marcus A Mall, Mark O Wielpütz, Hans-Ulrich Kauczor, Michael Puderbach

  European journal of radiology. 03/2011;

  Magnetic resonance imaging (MRI) gains increasing importance in the assessment of cystic fibrosis (CF) lung disease. The aim of this study was to develop a morpho-functional MR-scoring-system and to evaluate its intra- and inter-observer reproducibility and clinical practicability to monitor CF lung... [more] Magnetic resonance imaging (MRI) gains increasing importance in the assessment of cystic fibrosis (CF) lung disease. The aim of this study was to develop a morpho-functional MR-scoring-system and to evaluate its intra- and inter-observer reproducibility and clinical practicability to monitor CF lung disease over a broad severity range from infancy to adulthood. 35 CF patients with broad age range (mean 15.3years; range 0.5-42) were examined by morphological and functional MRI. Lobe based analysis was performed for parameters bronchiectasis/bronchial-wall-thickening, mucus plugging, abscesses/sacculations, consolidations, special findings and perfusion defects. The maximum global score was 72. Two experienced radiologists scored the images at two time points (interval 10weeks). Upper and lower limits of agreement, concordance correlation coefficients (CCC), total deviation index and coverage probability were calculated for global, morphology, function, component and lobar scores. Global scores ranged from 6 to 47. Intra- and inter-reader agreement for global scores were good (CCC: 0.98 (R1), 0.94 (R2), 0.97 (R1/R2)) and were comparable between high and low scores. Our results indicate that the proposed morpho-functional MR-scoring-system is reproducible and applicable for semi-quantitative evaluation of a large spectrum of CF lung disease severity. This scoring-system can be applied for the routine assessment of CF lung disease and maybe as endpoint for clinical trials.
• 1.95

  Impact points

  Percutaneous treatment of biliary cast syndrome after orthotopic liver transplantation: comparison of mechanical versus hydraulic rheolytic cast extraction.

  R López-Benítez, M O Wielpütz, M G H Bryant, Tom Ganten, G M Richter, N Flach, P J Hallscheidt

  Cardiovascular and interventional radiology. 11/2010; 34(5):998-1005.

  Biliary cast syndrome (BCS) is the presence of casts within the intrahepatic or extrahepatic biliary system after orthotopic liver transplantation. Our work compares two percutaneous methods for BCS treatment: the mechanical cast-extraction technique (MCE) versus the hydraulic cast-extraction (HCE) ... [more] Biliary cast syndrome (BCS) is the presence of casts within the intrahepatic or extrahepatic biliary system after orthotopic liver transplantation. Our work compares two percutaneous methods for BCS treatment: the mechanical cast-extraction technique (MCE) versus the hydraulic cast-extraction (HCE) technique using a rheolytic system. A total of 24 patients were included in the study. Six patients were referred for HCE, and 18 patients were treated with MCE. A statistically significant larger number of sessions was required in the MCE group (21.0, range 11 to 72 sessions) (p = 0.033). Median therapy duration was shorter in the HCE group at 2.4 months (range 2 to 5) compared with 6.7 months (range 3 to 39) in the MCE group (p < 0.001). Both patient acceptance was better and costs for total therapy were 40% less in the HCE group. No significant differences where found concerning clinical and biochemical improvement or graft and patient survival. The use of the hydraulic rheolytic system decreased total therapy time, thereby decreasing the induced inflammation time of the biliary tree. A significant benefit of HCE has been observed in our patients when we compare our results with those of MCE.
• 5.33

  Impact points

  (NDRG2) stimulates amiloride-sensitive Na+ currents in Xenopus laevis oocytes and fisher rat thyroid cells.

  Mark O Wielpütz, Il-Ha Lee, Anuwat Dinudom, Sheerazed Boulkroun, Nicolette Farman, David I Cook, Christoph Korbmacher, Robert Rauh

  The Journal of biological chemistry. 10/2007; 282(38):28264-73.

  Regulation of the epithelial sodium channel (ENaC) is highly complex and may involve several aldosterone-induced regulatory proteins. The N-Myc downstream-regulated gene 2 (NDRG2) has been identified as an early aldosterone-induced gene. Therefore, we hypothesized that NDRG2 may affect ENaC function... [more] Regulation of the epithelial sodium channel (ENaC) is highly complex and may involve several aldosterone-induced regulatory proteins. The N-Myc downstream-regulated gene 2 (NDRG2) has been identified as an early aldosterone-induced gene. Therefore, we hypothesized that NDRG2 may affect ENaC function. To test this hypothesis we measured the amiloride-sensitive (2 microm) whole cell current (DeltaI(ami)) in Xenopus laevis oocytes expressing ENaC alone or co-expressing ENaC and NDRG2. Co-expression of NDRG2 significantly increased DeltaI(ami) in some, but not, all batches of oocytes tested. An inhibitory effect of NDRG2 was never observed. Using a chemiluminescence assay we demonstrated that the NDRG2-induced increase in ENaC currents was accompanied by a similar increase in channel surface expression. The stimulatory effect of NDRG2 was preserved in oocytes maintained in a low sodium bath solution to prevent sodium feedback inhibition. These findings suggest that the stimulatory effect of NDRG2 is independent of sodium feedback regulation. Furthermore, the stimulatory effect of NDRG2 on ENaC was at least in part additive to that of Sgk1. A short isoform of NDRG2 also stimulated DeltaI(ami). Overexpression of NDRG2 and ENaC in Fisher rat thyroid cells confirmed the stimulatory effect of NDRG2 on ENaC-mediated short-circuit current (I(SC-ami)). In addition, small interference RNA against NDRG2 largely reduced I(SC-ami) in Fisher rat thyroid cells. Our results indicate that NDRG2 is a likely candidate to contribute to aldosterone-mediated ENaC regulation.