Publications by authors named "Markus Niemeyer"

Background: Perioperative antibiotic prophylaxis is an established concept to reduce the risk of surgical-site infections; however, the optimal treatment duration in prosthetic breast reconstruction is still controversial. This study evaluated a potential association between the perioperative antibiotic prophylaxis duration (≤24 hours versus >24 hours) and incidence of postoperative surgical-site infections in immediate implant-based breast reconstruction in breast cancer patients.

Methods: A descriptive, retrospective analysis of surgical-site infections after immediate implant-based breast reconstruction in breast cancer patients between January of 2011 and December of 2018 was performed.

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Article Synopsis
  • This study investigated whether immediate oncoplastic surgery (ONC) impacts local control rates when combined with adjuvant radiotherapy (RT) in breast cancer patients, comparing it with standard breast-conserving surgery (NONC).
  • The research included 965 patients, revealing no significant difference in local control rates, progression-free survival (PFS), or overall survival (OS) between the ONC and NONC groups after a median follow-up of 67 months.
  • Findings suggest that immediate oncoplastic surgery does not adversely affect the effectiveness of adjuvant whole breast radiotherapy in maintaining local control over breast cancer.
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Background: CXCR4 is a chemokine receptor frequently overexpressed in invasive breast cancer that has been shown to play a major role in signaling pathways involved in metastasis. The aim of this retrospective analysis was to assess the diagnostic performance of CXCR4-directed PET imaging in patients with breast cancer using the recently introduced CXCR4-targeted PET probe Ga-Pentixafor.

Results: Thirteen patients with first diagnosis of breast cancer, four patients with recurrent disease after primary breast cancer, and one patient with axillary lymph node metastasis of unknown primary underwent CXCR4-targeted PET imaging using Ga-Pentixafor.

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Purpose: Age dependent radiation sensitivity for DNA damage after in vitro blood exposure by computer tomography (CT) was investigated.

Materials And Methods: Radiation biomarkers (dicentrics and gammaH2AX) in blood samples of newborns, children under five years and adults after sham exposure (0 mGy), low-dose (41 mGy) and high-dose (978 mGy) in vitro CT exposure were analyzed.

Results: Significantly higher levels of dicentric induction were found for the single and combined newborns/children group compared to adults, by a factor of 1.

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X-ray magnetic circular dichroism spectroscopy has been used to characterize the electronic structure and magnetic moment of Cr2 (+) . Our results indicate that the removal of a single electron from the 4sσg bonding orbital of Cr2 drastically changes the preferred coupling of the 3d electronic spins. While the neutral molecule has a zero-spin ground state with a very short bond length, the molecular cation exhibits a ferromagnetically coupled ground state with the highest possible spin of S=11/2, and almost twice the bond length of the neutral molecule.

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In hepatitis C virus (HCV) infection, morbidity and mortality often result from extrahepatic disease manifestations. We provide evidence for a role of receptors of the innate immune system in virally induced inflammation of the endothelium in vitro and in vivo. Corresponding to the in vitro finding of an HCV-dependent induction of proinflammatory mediators in endothelial cells, mice treated with poly (I:C) exhibit a significant reduction in leukocyte rolling velocity, an increase in leukocyte adhesion to the vessel wall and an increased extravasation of leukocytes.

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Introduction: Inflammation and endothelium-derived superoxides are important pathomechanisms in atherothrombotic diseases. We could previously show that the tyrosine phosphatase SHP-1 acts as a negative regulator in endothelial superoxide production. In this study we investigated the influence of SHP-1 on platelet-endothelium interaction and arterial thrombosis in TNFα -induced endothelial inflammation in vivo.

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Introduction: Elevated serum levels of the proinflammatory cytokine tumor necrosis factor alpha (TNFα) correlate with an increased risk for atherothrombotic events and TNFα is known to induce prothrombotic molecules in endothelial cells. Based on the preexisting evidence for the impact of TNFα in the pathogenesis of autoimmune disorders and their known association with an acquired hypercoagulability, we investigated the effects of TNFα and the role of the TNF receptor subtypes TNFR1 and TNFR2 for arteriolar thrombosis in vivo.

Methods: Arteriolar thrombosis and platelet-rolling in vivo were investigated in wildtype, TNFR1-/-, TNFR2-/- and TNFR1-/R2-/- C57BL/6 mice using intravital microscopy in the dorsal skinfold chamber microcirculation model.

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Human umbilical vessels have been recognized as a valuable and widely available resource for vascular tissue engineering. Whereas endothelium-denuded human umbilical veins (HUVs) have been successfully seeded with a patient-derived neoendothelium, decellularized vessels may have additional advantages, due to their lower antigenicity. The present study investigated the effects of three different decellularization procedures on the histological, mechanical and seeding properties of HUVs.

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Ablative breast cancer surgery still includes the routine excision of the nipple-areola complex (NAC). Nipple-sparing mastectomy (NSM) removes the breast tissue leaving no or little retroareolar ductal tissue but preserves the entire skin of the breast and the NAC. There is some consensus that NSM might be an oncologically safe option for patients with small and peripherally located tumors and probably for high-risk patients with prophylactic mastectomy.

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Anionic tetrahydrofuran clusters (THF)(n) (-) (1≤n≤100) are studied with photoelectron imaging as gas-phase precursors for electrons solvated in THF. Photoelectron spectra of clusters up to n=5 show two peaks, one of which is attributed to a solvated open chain radical anion and the other to the closed THF ring. At n=6, the spectra change shape abruptly, which become more characteristic of (THF)(n) (-) clusters containing solvated electrons.

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Mesenchymal stem cells (MSC) represent a mixture of different cell types, of which only a minority is therapeutically relevant. Surface markers specifically identifying non-differentiated MSC from their differentiated progeny have not been described in sufficient detail. We here compare the gene expression profile of the in vivo bone-forming bone marrow-derived MSC (BM-MSC) with non-bone-forming umbilical vein stromal cells (UVSC) and other non-MSC.

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Objective: To assess migration of CD34(+) human stem cells to the bone marrow of athymic mice by using magnetic resonance (MR) imaging and Resovist, a contrast agent containing superparamagnetic iron oxide (SPIO) particles.

Methods: All animal and human procedures were approved by our institution's ethics committee, and women had given consent to donate umbilical cord blood (UCB). Balb/c-AnN Foxn1(nu)/Crl mice received intravenous injection of 1 x 10(6) (n=3), 5 x 10(6) (n=3) or 1 x 10(7) (n=3) human Resovist-labelled CD34(+) cells; control mice received Resovist (n=3).

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Background: Numerous authors take multiple predictive factors into account to decide whether or not the nipple-areola complex (NAC) can be conserved during mastectomy. These factors include the tumor-nipple distance, tumor size, axillary lymph node status, and lymphovascular invasion. Thus only a very limited percentage of patients can keep their NAC.

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Article Synopsis
  • The study examines the role of KIT signaling along with glycoprotein 130 (gp130) in maintaining human hematopoietic stem cells from umbilical cord blood.
  • Researchers found that while KIT-ligand (KL) alone did not support the maintenance of primitive progenitors, the combination of KL with oncostatin M (OSM) enhanced cell proliferation and improved the maintenance of immature progenitors.
  • The study reveals that OSM counteracts the loss of repopulating activity associated with KL stimulation by downregulating the ERK signaling pathway.
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Unlabelled: The integrin alpha(v)beta(3) is a key player in angiogenesis and metastasis. Our aim was to study the uptake patterns of the alpha(v)beta(3)-selective PET tracer (18)F-galacto-RGD in invasive ductal breast cancer.

Methods: Sixteen patients with primary (n = 12) or metastasized breast cancer (n = 4) were examined with (18)F-galacto-RGD PET.

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Purpose: The integrin alpha(v)beta3 plays a key role in angiogenesis and tumor cell metastasis and is therefore an important target for new therapeutic and diagnostic strategies. We have developed [18F]Galacto-RGD, a highly alpha(v)beta3-selective tracer for positron emission tomography (PET). Here, we show, in man, that the intensity of [18F]Galacto-RGD uptake correlates with alpha(v)beta3 expression.

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Article Synopsis
  • (18)F-Galacto-RGD is a new PET imaging tracer that targets the alpha v beta3 receptor, important in cancer processes like angiogenesis and metastasis.
  • In a study with 18 patients, the tracer was injected and analyzed for its dosimetry, showing over 95% was intact in the blood for up to 120 minutes, with rapid clearance and low background activity in tissues.
  • The findings indicate that (18)F-Galacto-RGD is metabolically stable and has a low radiation dose, making it a safe option for imaging molecular processes in cancer and aiding therapeutic monitoring.
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Background: The effect of reduced cardiopulmonary bypass (CPB) prime volume by retrograde autologous priming (RAP) was studied.

Methods: Twenty patients undergoing elective coronary artery bypass grafting were randomized to either standard prime (SP) volume (1,602 +/- 202 mL crystalloid prime, n = 10) or RAP (395 +/- 150 mL). RAP was performed by draining crystalloid prime from the arterial and venous lines into a recirculation bag before CPB.

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