Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Kerstin Weitmann is active.

Publication


Featured researches published by Kerstin Weitmann.


Circulation | 2007

Utility of Doppler Echocardiography and Tissue Doppler Imaging in the Estimation of Diastolic Function in Heart Failure With Normal Ejection Fraction A Comparative Doppler-Conductance Catheterization Study

Mario Kasner; Dirk Westermann; Paul Steendijk; Regina Gaub; Ursula Wilkenshoff; Kerstin Weitmann; Wolfgang Hoffmann; Wolfgang Poller; Heinz-Peter Schultheiss; Matthias Pauschinger; Carsten Tschöpe

Background— Various conventional and tissue Doppler echocardiographic indexes were compared with pressure–volume loop analysis to assess their accuracy in detecting left ventricular (LV) diastolic dysfunction in patients with heart failure with normal ejection fraction (HFNEF). Methods and Results— Diastolic dysfunction was confirmed by pressure–volume loop analysis obtained by conductance catheter in 43 patients (19 men) with HFNEF. Their Doppler indexes were compared with those of 12 control patients without heart failure symptoms and with normal ejection fraction. Invasively measured indexes for diastolic relaxation (&tgr;, dP/dtmin), LV end-diastolic pressure, and LV end-diastolic pressure–volume relationship (stiffness, b [dP/dV], and stiffness constant, &bgr;) were correlated with several conventional mitral flow and tissue Doppler imaging indexes. Conventional Doppler indexes correlated moderately with the degree of LV relaxation index, &tgr; (E/A: r=−0.36, P=0.013; isovolumic relaxation time: r=0.31, P=0.040) and b (deceleration time: r=0.39, P=0.012) but not with &bgr;, in contrast to the tissue Doppler imaging indexes E’/A’lateral (r=−0.37, P=0.008) and E/E’lateral (r=0.53, P<0.001). Diastolic dysfunction was detected in 70% of the HFNEF patients by mitral flow Doppler but in 81% and 86% by E’/A’lateral, and E/E’lateral, respectively. Conclusions— Of all echocardiographic parameters investigated, the LV filling index E/E’lateral was identified as the best index to detect diastolic dysfunction in HFNEF in which the diagnosis of diastolic dysfunction was confirmed by conductance catheter analysis. We recommend its use as an essential tool for noninvasive diagnostics of diastolic function in patients with HFNEF.


Circulation | 2008

Role of Left Ventricular Stiffness in Heart Failure With Normal Ejection Fraction

Dirk Westermann; Mario Kasner; Paul Steendijk; Frank Spillmann; Alexander Riad; Kerstin Weitmann; Wolfgang Hoffmann; Wolfgang Poller; Matthias Pauschinger; Heinz-Peter Schultheiss; Carsten Tschöpe

Background— Increased left ventricular stiffness is a distinct finding in patients who have heart failure with normal ejection fraction (HFNEF). To elucidate how diastolic dysfunction contributes to heart failure symptomatology during exercise, we conducted a study using an invasive pressure-volume loop approach and measured cardiac function at rest and during atrial pacing and handgrip exercise. Methods and Results— Patients with HFNEF (n=70) and patients without heart failure symptoms (n=20) were enrolled. Pressure-volume loops were measured with a conductance catheter during basal conditions, handgrip exercise, and atrial pacing with 120 bpm to analyze diastolic and systolic left ventricular function. During transient preload reduction, the diastolic stiffness constant was measured directly. Diastolic function with increased stiffness was significantly impaired in patients with HFNEF during basal conditions. This was associated with increased end-diastolic pressures during handgrip exercise and with decreased stroke volume and a leftward shift of pressure-volume loops during atrial pacing. Conclusions— Increased left ventricular stiffness contributed to increased end-diastolic pressure during handgrip exercise and decreased stroke volume during atrial pacing in patients with HFNEF. These data suggest that left ventricular stiffness modulates cardiac function in HFNEF patients and suggests that diastolic dysfunction with increased stiffness is a target for treating HFNEF.


International Journal of Cancer | 2009

Prevalence and frequency of circulating t(14;18)-MBR translocation carrying cells in healthy individuals

Frank Schüler; Lars Dölken; Carsten Hirt; Thomas Kiefer; Tobias Berg; Gerhard Fusch; Kerstin Weitmann; Wolfgang Hoffmann; Christoph Fusch; Siegfried Janz; Charles S. Rabkin; Gottfried Dölken

The t(14;18) translocation is a common genetic aberration that can be seen as an early step in pathogenesis of follicular lymphoma (FL). The significance of low level circulating t(14;18)‐positive cells in healthy individuals as clonal lymphoma precursors or indicators of risk is still unclear. We determined the age dependent prevalence and frequency of BCL2/IgH rearrangements in 715 healthy individuals ranging from newborns to octo‐ and nonagenarians. These results were compared with number of circulating t(14;18)‐positive cells in 108 FL patients at initial presentation. The overall prevalence of BCL2/IgH junctions in this large sample was 46% (327/715). However, there was a striking dependence upon age. Specifically, among individuals up to 10 years old, none had detectable circulating t(14;18)‐positive cells. In the age groups representing 10–50 years old, we found a steady elevation in the prevalence of BCL2/IgH junctions up to a prevalence of 66%. Further increases of the prevalence in individuals older than 50 years were not seen. The mean frequency of BCL2/IgH junctions in healthy individuals ≥40 years (18–26 × 10−6) was significantly higher than in younger subjects (7–9 × 10−6). Four percent (31/715) of individuals carried more than one t(14;18)‐positive cell per 25,000 peripheral blood mononuclear cells (PBMNCs). In comparison, 108 stage III/IV FL patients had a median number of circulating t(14;18)‐positive malignant FL cells of about 9200/1 million PBMNCs (range 7–1,000,000). These findings will further improve the understanding of the relevance of t(14;18)‐positive cells in healthy individuals as a risk marker toward the development into lymphoma precursors.


Circulation | 2009

Prevention of cardiac dysfunction in acute coxsackievirus B3 cardiomyopathy by inducible expression of a soluble coxsackievirus-adenovirus receptor.

Sandra Pinkert; Dirk Westermann; Xiaomin Wang; Karin Klingel; Andrea Dörner; Konstantinos Savvatis; Tobias Grössl; Stefanie Krohn; Carsten Tschöpe; Heinz Zeichhardt; Katja Kotsch; Kerstin Weitmann; Wolfgang Hoffmann; Heinz-Peter Schultheiss; Owen Bradley Spiller; Wolfgang Poller; Henry Fechner

Background— Group B coxsackieviruses (CVBs) are the prototypical agents of acute myocarditis and chronic dilated cardiomyopathy, but an effective targeted therapy is still not available. Here, we analyze the therapeutic potential of a soluble (s) virus receptor molecule against CVB3 myocarditis using a gene therapy approach. Methods and Results— We generated an inducible adenoviral vector (AdG12) for strict drug-dependent delivery of sCAR-Fc, a fusion protein composed of the coxsackievirus-adenovirus receptor (CAR) extracellular domains and the carboxyl terminus of human IgG1-Fc. Decoy receptor expression was strictly doxycycline dependent, with no expression in the absence of an inducer. CVB3 infection of HeLa cells was efficiently blocked by supernatant from AdG12-transduced cells, but only in the presence of doxycycline. After liver-specific transfer, AdG12 (plus doxycycline) significantly improved cardiac contractility and diastolic relaxation compared with a control vector in CVB3-infected mice if sCAR-Fc was induced before infection (left ventricular pressure 59±3.8 versus 45.4±2.7 mm Hg, median 59 versus 45.8 mm Hg, P<0.01; dP/dtmax 3645.1±443.6 versus 2057.9±490.2 mm Hg/s, median 3526.6 versus 2072 mm Hg/s, P<0.01; and dP/dtmin −2125.5±330.5 versus −1310.2±330.3 mm Hg/s, median −2083.7 versus −1295.9 mm Hg/s, P<0.01) and improved contractility if induced concomitantly with infection (left ventricular pressure 76.4±19.2 versus 56.8±10.3 mm Hg, median 74.8 versus 54.4 mm Hg, P<0.05; dP/dtmax 5214.2±1786.2 versus 3011.6±918.3 mm Hg/s, median 5182.1 versus 3106.6 mm Hg/s, P<0.05), respectively. Importantly, hemodynamics of animals treated with AdG12 (plus doxycycline) were similar to uninfected controls. Preinfection induction of sCAR-Fc completely blocked and concomitant induction strongly reduced cardiac CVB3 infection, myocardial injury, and inflammation. Conclusion— AdG12-mediated sCAR-Fc delivery prevents cardiac dysfunction in CVB3 myocarditis under prophylactic and therapeutic conditions.


American Heart Journal | 2010

Comparison of rotational with conventional coronary angiography

Klaus Empen; Eberhard Kuon; Astrid Hummel; Chris Gebauer; Marcus Dörr; Raik Könemann; Wolfgang Hoffmann; Alexander Staudt; Kerstin Weitmann; Thorsten Reffelmann; Stephan B. Felix

BACKGROUND Patient radiation exposure and consumption of contrast medium are considered major risks of diagnostic coronary angiography (CA). Rotation of the C-arm during CA could provide similar diagnostic accuracy and lower radiation exposure and contrast medium consumption. METHODS To compare feasibility, safety, diagnostic accuracy, patient radiation exposure, and consumption of contrast medium of rotational CA with the invasive standard technique, intraindividual comparisons of the results obtained by both techniques were performed in 235 patients with an indication for first-time elective CA. In addition to conventional angiography, we performed 2 isocentric radiographic coronary spins with cranial and caudal tilts by 20 degrees around the left coronary artery and 1 strict posteroanterior rotational spin around the right coronary artery. RESULTS In 16 patients, rotational CA was not performed because of safety concerns. In a further 12 patients, image quality of rotational scans was considered inadequate. In the remaining 207 patients, both modes of CA were proven suitable for anonymized, separate analysis by 3 independent cardiologists. Intraindividual comparison of both CA modes revealed a high degree of diagnostic agreement (Cohen (K) >0.8 for all cardiologists and for each coronary segment). Contrast medium volume during rotational CA and conventional CA amounted to 31.9 +/- 4.5 mL versus 52.2 +/- 8.0 mL (P < .001) and patient radiation exposure amounted to 5.0 +/- 2.6 Gy × cm(2) versus 11.5 +/- 5.5 Gy × cm(2) (P < .001), respectively. CONCLUSIONS Rotational CA represents a safe and feasible method in clinical routine. Whereas diagnostic accuracy is similar to the usual conventional mode, consumption of contrast medium and patient radiation exposure are significantly reduced.


Clinical Nutrition | 2011

Fortification of breast milk in VLBW infants: Metabolic acidosis is linked to the composition of fortifiers and alters weight gain and bone mineralization

Niels Rochow; Frank Jochum; Anke Redlich; Zuzana Korinekova; Kristina Linnemann; Kerstin Weitmann; Günther Boehm; Heike Müller; Hermann Kalhoff; Heinrich Topp; Wolfgang Hoffmann; Christoph Fusch

BACKGROUND & AIMS Study objectives were to test (a) whether increased incidence of metabolic acidosis (MA) was caused by introduction of a new commercially available fortifier for breast milk, (b) if so, whether its modification would decrease the incidence of MA and (c) to analyze the impact of MA on growth. METHODS Double-blind randomized design. Healthy breast-fed infants (≤34 gestational weeks). Primary outcome measure was incidence of MA (BE < -6.0 mmol/L). Secondary outcome measures were growth, bone mineral content (BMC), vital signs, treatment with sodium hydrogen carbonate and Ca and laboratory parameters (pH, pCO₂, HCO₃⁻, electrolytes). RESULTS Part 1 (comparison of standard (SF) and new fortifier (NF)): Interim analysis showed MA in 1 out of 7 (SF) and 7 out of 8 (NF) infants, p = 0.01; therefore the study was interrupted; subsequently the fortifier was adapted by modifying mineral components. Part 2 (comparison of SF and reformulated fortifier (RF)): MA occurred in 3 out of 15 (SF) and 6 out of 19 (RF), p = 0.7. When data of all infants studied, those with MA had lower mean weight gain (median: 9 vs. 21 g/kg/d, p < 0.01) and lower BMC (1.6% vs. 1.9% BMC/lean, p = 0.04) at discharge. CONCLUSIONS When fed fortified breast milk, mild MA spontaneously may develop in 20-30% of VLBW infants. A fortifier with an inappropriate composition may increase the severity and frequency of MA. Our data show that weight gain and BMC seem to be related to acid-base homeostasis. It may be speculated that inadequate growth of fully fed preterm infants is triggered more often by imbalances of acid-base status than previously expected.


Journal of Biological Chemistry | 2012

Variants of Toll-like Receptor 4 Predict Cardiac Recovery in Patients with Dilated Cardiomyopathy

Alexander Riad; Henriette E. Meyer zu Schwabedissen; Kerstin Weitmann; Lars R. Herda; Marcus Dörr; Klaus Empen; Arne G. Kieback; Astrid Hummel; Marcus Reinthaler; Marcus Grube; Karin Klingel; Matthias Nauck; Reinhard Kandolf; Wolfgang Hoffmann; Heyo K. Kroemer; Stephan B. Felix

Background: The impact of polymorphisms of TLR4 on left ventricular performance in DCM patients is unknown. Results: Patients carrying TLR4 variants had reduced improvement of left ventricular function and dilation and no increase in NT-pro-BNP level at follow up when compared with wild type genes. Conclusion: TLR4 variants predict cardiac recovery in DCM. Significance: This is the first study to investigate the impact of an innate immune receptor on cardiac recovery in human DCM. The clinical course of patients with dilated cardiomyopathy (DCM) varies from cardiac recovery to end stage heart failure. The etiology of this variability is largely unknown. In this study, we investigated the impact of coding polymorphisms of the innate immune protein Toll-like receptor 4 (TLR4) on left ventricular performance in patients with DCM. Two variants of TLR4 (rs4986790, TLR4 c.1187A→G, p.299D→G and rs4986791,TLR4 c.1487C→T, p.T399I) were investigated in 158 patients with DCM. Other reasons for heart failure were excluded by coronary angiography, myocardial biopsy, and echocardiography. Risk factors, age, gender, or treatment did not differ among the groups. At the follow-up evaluation (median 4.0–5.4 months), patients carrying the TLR4 wild type gene displayed cardiac recovery under intense medical heart failure therapy indexed by reduced left ventricular dilation, improved left ventricular ejection fraction, and reduced NT-probrain natriuretic peptide blood level when compared with the initial evaluation. In contrast, patients carrying both the rs4986790 and the rs4986791 variant showed significantly reduced improvement of left ventricular ejection fraction (p = 0.006) and left ventricular dilation (p = 0.015) at the follow-up evaluation when compared with carriers of the wild type gene under the same treatment conditions. In addition, NT-probrain natriuretic peptide level in carriers of both TLR4 variants did not change significantly at the follow up when compared with the first evaluation. Among patients with DCM, the presence of the TLR4 variants rs4986790 and rs4986791 predicts impaired cardiac recovery independently of medical treatment or cardiac risk factors.


Transfusion | 2016

A population‐based longitudinal study on the implications of demographics on future blood supply

Andreas Greinacher; Kerstin Weitmann; Anne Lebsa; Ulf Alpen; Doris Gloger; Wolfgang Stangenberg; V. Kiefel; Wolfgang Hoffmann

Changes in demographics with increases in older age groups and decreases in younger age groups imply an increased demand for blood transfusions paralleled by a decrease in the population eligible for blood donation. However, more restrictive transfusion triggers and the patient blood management initiative also reduce the demand for red blood cells (RBCs). Eastern Germany is a model region for the impact of demographic changes, which manifest in this region approximately 10 years earlier than in other regions due to the 50% birth rate decline after 1989.


Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren | 2013

Long-term efficacy of a mini-course in radiation-reducing techniques in invasive cardiology.

E. Kuon; K. Empen; Kerstin Weitmann; A. Staudt; A. Hummel; M. Dörr; T. Reffelmann; W. Hoffmann; S. B. Felix

PURPOSE To validate the long-term efficacy of a 90-min. educational mini-course in less-irradiating cardiac interventional techniques. MATERIALS AND METHODS Before, two months after, and two years after the mini-course (periods I, II, and III), we analyzed the following radiation dose parameters for ten coronary angiographies (CA), performed by each of 7 cardiologists: total dose-area product (DAP), radiographic and fluoroscopic DAP fractions, number of radiographic frames and runs, and fluoroscopy time. RESULTS The median patient DAP for periods I, II and III was 31.4, 15.8 and 8.5 Gy × cm2, respectively. The long-term effect was related to shorter median fluoroscopy times (180, 172, and 120 s), shorter (57, 52, and 45) and fewer (12, 12, and 10) radiographic runs, consistent collimation and restriction to an adequate image quality. Both radiographic DAP/frame (28.7, 17.0, and 18.4 mGy × cm2) and fluoroscopic DAP/second (45.7, 24.2, and 10.0 mGy × cm2) decreased significantly. The multivariate linear regression analysis confirmed the increasing efficacy of the mini-course itself (-44.6 and -60.7%), and revealed a decreasing influence of the interventionalists experience (-8.6% and -4.9% per 1,000 CAs, lifelong performed until the mini-course). The number of CAs performed after the mini-course did not influence the long-term DAP results. CONCLUSION The presented educational mini-course allows a significant, long-lasting, and apparently ongoing reduction of patient radiation exposure due to CA. A self-surveillant documentation of relevant radiation parameters is well suited to monitor and improve each operators individual long-term radiation-reducing efforts.


Oncotarget | 2016

Expression of S1P metabolizing enzymes and receptors correlate with survival time and regulate cell migration in glioblastoma multiforme

Sandra Bien-Möller; Sandra Lange; Tobias Holm; Andreas Böhm; Heiko Paland; Johannes Küpper; Susann Herzog; Kerstin Weitmann; Christoph Havemann; Silke Vogelgesang; Sascha Marx; Wolfgang Hoffmann; Henry W. S. Schroeder; Bernhard Rauch

A signaling molecule which is involved in proliferation and migration of malignant cells is the lipid mediator sphingosine-1-phosphate (S1P). There are hints for a potential role of S1P signaling in malignant brain tumors such as glioblastoma multiforme (GBM) which is characterized by a poor prognosis. Therefore, a comprehensive expression analysis of S1P receptors (S1P1-S1P5) and S1P metabolizing enzymes in human GBM (n = 117) compared to healthy brain (n = 10) was performed to evaluate their role for patients survival. Furthermore, influence of S1P receptor inhibition on proliferation and migration were studied in LN18 GBM cells. Compared to control brain, mRNA levels of S1P1, S1P2, S1P3 and S1P generating sphingosine kinase-1 were elevated in GBM. Kaplan-Meier analyses demonstrated an association between S1P1 and S1P2 with patients survival times. In vitro, an inhibitory effect of the SphK inhibitor SKI-II on viability of LN18 cells was shown. S1P itself had no effect on viability but stimulated LN18 migration which was blocked by inhibition of S1P1 and S1P2. The participation of S1P1 and S1P2 in LN18 migration was further supported by siRNA-mediated silencing of these receptors. Immunoblots and inhibition experiments suggest an involvement of the PI3-kinase/AKT1 pathway in the chemotactic effect of S1P in LN18 cells. In summary, our data argue for a role of S1P signaling in proliferation and migration of GBM cells. Individual components of the S1P pathway represent prognostic factors for patients with GBM. Perspectively, a selective modulation of S1P receptor subtypes could represent a therapeutic approach for GBM patients and requires further evaluation.

Collaboration


Dive into the Kerstin Weitmann's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Klaus Empen

University of Greifswald

View shared research outputs
Top Co-Authors

Avatar

Marcus Dörr

University of Greifswald

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

A. Riad

University of Greifswald

View shared research outputs
Researchain Logo
Decentralizing Knowledge