Publications by authors named "Alexander Langheinrich"

Purpose: This study aimed to compare clinical results and fusion rates of uncoated polyetheretherketone (PEEK) cages with titanium-coated PEEK cages in posterior lumbar interbody fusion (PLIF) surgery.

Methods: A prospective randomised study including 60 patients with one- or two-segment lumbar degenerative diseases. Patients received either titanium-coated PEEK cages (group A) or uncoated PEEK cages (group B).

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The management of complex fractures at the time of revision surgery remains one of the most challenging tasks for orthopaedic trauma surgeons. As the major principle of treatment remains to achieve an anatomic reduction and a stable fixation, precise preoperative diagnostics and treatment planning are of utmost importance. Thus, knowledge of the 3-dimensional anatomy of the fracture site and its surrounding tissue is indispensable.

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Background: Following myocardial infarction (MI), peri-infarct myocardial edema formation further impairs cardiac function. Extracellular RNA (eRNA) released from injured cells strongly increases vascular permeability. This study aimed to assess the role of eRNA in MI-induced cardiac edema formation, infarct size, cardiac function, and survival after acute MI and to evaluate the therapeutic potential of ribonuclease 1 (RNase-1) treatment as an eRNA-degrading intervention.

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Purpose: Neovascularization is essential for bone regeneration in fractures. This study aimed to investigate the microvascular morphology and distribution in the non-injured femur and the neovascularization of the metaphyseal critical size defect in a small animal model of osteoporosis.

Materials And Methods: Female rats (n=7) were ovariectomized (OVX) and received a multideficiency diet.

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Bone loss is a symptom related to disease and age, which reflects on bone cells and ECM. Discrepant regulation affects cell proliferation and ECM localization. Rat model of osteoporosis (OVX) was investigated against control rats (Sham) at young and old ages.

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Background: Recently, analysis of bone from knockout mice identified muscarinic acetylcholine receptor subtype M3 (mAChR M3) and nicotinic acetylcholine receptor (nAChR) subunit α2 as positive regulator of bone mass accrual whereas of male mice deficient for α7-nAChR (α7KO) did not reveal impact in regulation of bone remodeling. Since female sex hormones are involved in fair coordination of osteoblast bone formation and osteoclast bone degradation we assigned the current study to analyze bone strength, composition and microarchitecture of female α7KO compared to their corresponding wild-type mice (α7WT).

Methods: Vertebrae and long bones of female 16-week-old α7KO (n = 10) and α7WT (n = 8) were extracted and analyzed by means of histological, radiological, biomechanical, cell- and molecular methods as well as time of flight secondary ion mass spectrometry (ToF-SIMS) and transmission electron microscopy (TEM).

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Nonalcoholic fatty liver disease has been linked to cardiovascular diseases and atherosclerosis. The aim of the current study was to characterize the hepatic pathology leading to fibrosis and tumors in a murine model of atherosclerosis. Male apolipoprotein E/low-density lipoprotein receptor double-knockout mice (AL) mice were fed with a high fat and high cholesterol western diet for 35 weeks (AL mice on WD).

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Purpose: The prevalence of systemic atherosclerosis and overactive bladder/detrusor overactivity increases almost simultaneously with age but an association between these diseases has not yet been proved. We evaluated changes in bladder function and morphology, including vascularization, in apoE(-/-)LDLR(-/-) double knockout mice with systemic atherosclerosis but without central nervous system involvement.

Materials And Methods: Cystometry was performed in awake, freely moving 60-week-old apoE(-/-)LDLR(-/-) mice and C57BL/6N controls.

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For assessing mechanical properties of osteoporotic bone, biomechanical testing combined with in silico modeling plays a key role. The present study focuses on microscopic mechanical bone properties in a rat model of postmenopausal osteoporosis. Female Sprague-Dawley rats were (1) euthanized without prior interventions, (2) sham-operated, and (3) subjected to ovariectomy combined with a multi-deficiencies diet.

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Plaque progression in atherosclerosis is closely connected to angiogenesis due to vasa vasorum (VV) growth. Objective of this study was to determine the unknown long-term effect of thalidomide on adventitial VV neovascularization and plaque progression using nano-focussed computed tomography (nano-CT). Proliferation and migration assays in human coronary artery endothelial cells (HCAEC) measured number of viable cells after incubation with thalidomide.

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In estrogen-deficient, postmenopausal women, vitamin D and calcium deficiency increase osteoporotic fracture risk. Therefore, a new rat model of combined ovariectomy and multiple-deficient diet was established to mimic human postmenopausal osteoporotic conditions under nutrient deficiency. Sprague-Dawley rats were untreated (control), laparatomized (sham), or ovariectomized and received a deficient diet (OVX-Diet).

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Discrepancies in bone healing between osteoporotic and non-osteoporotic bone remain uncertain. The focus of the current work is to evaluate potential healing discrepancies in a metaphyseal defect model in rat femora. Female Sprague-Dawley rats were either ovariectomized (OVX, n=14) and combined with a calcium-, phosphorus- and vitamin D3-, soy- and phytoestrogen-free diet or received SHAM operation with standard diet rat (SHAM, n=14).

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Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels.

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Many postmenopausal women have vitamin D and calcium deficiency. Therefore, vitamin D and calcium supplementation is recommended for all patients with osteopenia and osteoporosis. We used an experimental rat model to test the hypothesis that induction of osteoporosis is more efficiently achieved in peripheral bone through combining ovariectomy with a unique multi-deficiencies diet (vitamin D depletion and deficient calcium, vitamin K and phosphorus).

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Background: Osteoporosis is a multi-factorial, chronic, skeletal disease highly prevalent in post-menopausal women and is influenced by hormonal and dietary factors. Because animal models are imperative for disease diagnostics, the present study establishes and evaluates enhanced osteoporosis obtained through combined ovariectomy and deficient diet by DEXA (dual-energy X-ray absorptiometry) for a prolonged time period.

Material/methods: Sprague-Dawley rats were randomly divided into sham (laparotomized) and OVX-diet (ovariectomized and fed with deficient diet) groups.

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The intention of this study was to establish a new critical size animal model that represents clinically relevant situations with osteoporotic bone status and internally fixated metaphyseal defect fractures in which biomaterials for the enhancement of fracture healing in osteoporotic fracture defects can be studied. Twenty-eight rats were ovariectomized (OVX) and treated with a calcium-, phosphorus-, vitamin D3-, soy- and phytoestrogen-free diet. After 3months Dual-energy X-ray absorptiometry measurements showed statistically significant reductions in bone mineral density of the spine of -25.

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Nanomedicine comprises a significant potential to approach the therapy of severe diseases. Knowledge of nanoparticle behavior at the target site would contribute to the development of specialized tools for respiratory medicine. Here, we were interested in the potential of micro-computed tomography (μCT) imaging to monitor the pulmonary distribution of polymeric nanoparticles.

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Aims: Increasing collagen synthesis was observed in lung after stimulation of nicotinic and muscarinic acetylcholine receptors (nAChR and mAChR) on fibroblasts. Since collagen synthesis is an important process during fracture healing and bone remodelling, we asked whether cholinergic receptors are involved in bone collagen production.

Main Methods: In the present study we analysed 16 week old male knockout mice for nAChRα7 (α7-KO) and mAChR M3R (M3R-KO) in correlation to their corresponding wild types (WT).

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Background: As women are the population most affected by multifactorial osteoporosis, research is focused on unraveling the underlying mechanism of osteoporosis induction in rats by combining ovariectomy (OVX) either with calcium, phosphorus, vitamin C and vitamin D2/D3 deficiency, or by administration of glucocorticoid (dexamethasone).

Material/methods: Different skeletal sites of sham, OVX-Diet and OVX-Steroid rats were analyzed by Dual Energy X-ray Absorptiometry (DEXA) at varied time points of 0, 4 and 12 weeks to determine and compare the osteoporotic factors such as bone mineral density (BMD), bone mineral content (BMC), area, body weight and percent fat among different groups and time points. Comparative analysis and interrelationships among osteoporotic determinants by regression analysis were also determined.

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Bony integration of biomaterials is a complex process in which angiogenesis plays a crucial role. We evaluated micro- and nano-CT imaging to demonstrate and quantify neovascularization in bony integration of a biomaterial and to give an image based estimation for the needed resolution for imaging angiogenesis in an animal model of femora defect healing. In 8 rats 5mm full-size defects were created at the left femur that was filled with silica-collagen bone substitute material and internally fixed with plate osteosynthesis.

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It is well known that recanalization of thrombosed cerebral sinuses occurs early but without marked influence on the long-term outcome and on final venous infarct volume on magnetic resonance imaging. To better understand the possible microvascular mechanisms behind these clinical observations, we evaluated the sequels of subacute superior sagittal sinus (SSS) thrombosis in rats using micro- and nano-CT imaging of the same specimen to provide large volume and high resolution CT image data respectively. SSS thrombosis was induced in 11 animals which were euthanized after 6h (n=4) or 6 weeks (n=7).

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Background: The apoE-/-/LDL-/- double knockout mice are bearing considerable structural homology to human atherosclerosis. We hypothesized, that advanced lesion formation in the renal artery is associated with kidney alterations in these mice.

Methods: Kidneys from apoE-/-/LDL-/- double knockout mice at the age of 80 weeks (n = 6) and C57/BL control mice (n = 5) were infused with Microfil, harvested and scanned with micro-CT (12 mum cubic voxels) and Nano-CT (900 nm cubic voxels).

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Structural data about the human lung fine structure are mainly based on stereological methods applied to serial sections. As these methods utilize 2D images, which are often not contiguous, they suffer from inaccuracies which are overcome by analysis of 3D micro-CT images of the never-sectioned specimen. The purpose of our study was to generate a complete data set of the intact three-dimensional architecture of the human acinus using high-resolution synchrotron-based micro-CT (synMCT).

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In monitoring of recanalization and in sonothrombolysis, contrast-enhanced ultrasound (CEUS) is applied in extended time protocols. As extended use may increase the probability of unwanted effects, careful safety evaluation is required. We investigated the safety profile and beneficial effects of CEUS in a reperfusion model.

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Background: Animal models of focal cerebral ischemia are widely used in stroke research. The purpose of our study was to evaluate and compare the cerebral macro- and microvascular architecture of rats in two different models of permanent middle cerebral artery occlusion using an innovative quantitative micro- and nano-CT imaging technique.

Methods: 4h of middle cerebral artery occlusion was performed in rats using the macrosphere method or the suture technique.

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