University of Zrich


University of Zrich

Time filter
Source Type

Ihrler S.,Ludwig Maximilians University of Munich | Rath C.,Ludwig Maximilians University of Munich | Rath C.,University of Zrich | Zengel P.,Ludwig Maximilians University of Munich | And 3 more authors.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology | Year: 2010

Objectives: The pathogenesis of acinar enlargement in sialadenosis is obscure. As myoepithelial cells had been reported to show degenerative changes, we decided to investigate the possible role of functionally deficient myoepithelial cells in the development of sialadenosis. Study design: This study was a morphometric analysis of glands immunohistochemically stained for CK14, α-actin, and Ki67 in 10 cases of sialadenosis and 11 normal parotids. Results: In sialadenosis, acini were much larger; there was a minor decrease in the density of the distribution of myoepithelial cells stained for CK14 and a major decrease in the density of the distribution and thickness of the myofilament component of myoepithelial cells stained for α-actin; and the proliferation of acinar and myoepithelial cells was reduced. Conclusions: Our results demonstrate a major loss and thinning of the myofilament component of the myoepithelial cells and thereby a loss of mechanical support for the acini in sialadenosis. This possibly allows acinar cells to expand as secretory granules accumulate intracellularly to produce the great acinar enlargement. This functional myoepithelial insufficiency is possibly a consequence of an autonomic neuropathy secondary to severe metabolic or hormonal disorders. © 2010 Mosby, Inc.

Middelboe M.,Copenhagen University | Glud R.N.,University of Southern Denmark | Glud R.N.,Greenland Institute of Natural Resources | Glud R.N.,Scottish Association for Marine Science | And 2 more authors.
Aquatic Microbial Ecology | Year: 2011

Subsurface abundance and distribution of viruses and prokaryotes was determined along a depth profile, down to 96 m below seafloor (96 mbsf), at Challenger Mound from the Porcubine Seabight (IODP Expedition 307). Viral and prokaryotic abundance decreased exponentially with sediment depth from 1.0 × 108 viruses cm-3 and 3.8 × 106 cells cm-3 at 4 mbsf to 4.9 × 106 viruses cm-3 and 9.8 × 105 cells cm-3 at 96 mbsf. The age of the sediment ranges from ca. 0.5 million yr before present (Ma) at 4 mbsf to ca. 2 Ma at 96 mbsf. Assuming that the decline in viral abundance with depth reflects a gradual decay of the viral assemblage over time, the estimated decay rate of the viral community is 1.2 × 10-6 ± 0.3 × 10 -6 (SD) yr-1, corresponding to a half-life of the viral community of 5.8 × 105 yr. Measurements of viral and prokaryotic change in abundance were performed in incubations of undiluted, but homogenized, sediment samples (13.3 and 79.8 mbsf) in anaerobic bags. Viral abundance decreased rapidly (decay rates of 0.010 ± 0.002 [SD] and 0.022 ± 0.018 [SD] h--1, respectively) in the incubations, suggesting that homogenization exposed the viruses to degradation processes. We hypothesize that most of the deep subsurface viral communities inhabit a microenvironment where the viruses are protected against decay, and can therefore persist in undisturbed sediments for hundreds of thousands, perhaps even millions, of years. © Inter-Research 2011.

Heimhofer U.,Leibniz University of Hanover | Hochuli P.-A.,University of Zrich | Burla S.,ETH Zurich | Oberli F.,ETH Zurich | And 3 more authors.
Geological Magazine | Year: 2012

The late Early Cretaceous greenhouse climate has been studied intensively based on proxy data derived essentially from open marine archives. In contrast, information on continental climatic conditions and on the accompanying response of vegetation is relatively scarce, most notably owing to the stratigraphic uncertainties associated with many Lower Cretaceous terrestrial deposits. Here, we present a palynological record from Albian near-shore deposits of the Lusitanian Basin of W Portugal, which have been independently dated using Sr-isotope signals derived from low-Mg oyster shell calcite. 87Sr/86Sr values fluctuate between 0.707373 ± 0.00002 and 0.707456 ± 0.00003; absolute values and the overall stratigraphic trend match well with the global open marine seawater signature during Albian times. Based on the new Sr-isotope data, existing biostratigraphic assignments of the succession are corroborated and partly revised. Spore-pollen data provide information on the vegetation community structure and are flanked by sedimentological and clay mineralogical data used to infer the overall climatic conditions prevailing on the adjacent continent. Variations in the distribution of climate-sensitive pollen and spores indicate distinct changes in moisture availability across the studied succession with a pronounced increase in hygrophilous spores in late Early Albian times. Comparison with time-equivalent palynofloras from the Algarve Basin of southern Portugal shows pronounced differences in the xerophyte/hygrophyte ratio, interpreted to reflect the effect of a broad arid climate belt covering southern and southeastern Iberia during Early Albian times. © 2012 Cambridge University Press.

Akinde M.,Norwegian Meteorological Institute | Bhlen M.H.,University of Zrich | Chatziantoniou D.,Athens University of Economics and Business | Gamper J.,Free University of Bozen Bolzano
Information Systems | Year: 2011

The SQL:2003 standard introduced window functions to enhance the analytical processing capabilities of SQL. The key concept of window functions is to sort the input relation and to compute the aggregate results during a scan of the sorted relation. For multi-dimensional OLAP queries with aggregation groups defined by a general θ condition an appropriate ordering does not exist, though, and hence expensive join-based solutions are required. In this paper we introduce θconstrained multi-dimensional aggregation (θMDA), which supports multi-dimensional OLAP queries with aggregation groups defined by inequalities. θMDA is not based on an ordering of the data relation. Instead, the tuples that shall be considered for computing an aggregate value can be determined by a general θ condition. This facilitates the formulation of complex queries, such as multi-dimensional cumulative aggregates, which are difficult to express in SQL because no appropriate ordering exists. We present algebraic transformation rules that demonstrate how the θMDA interacts with other operators of a multi-set algebra. Various techniques for achieving an efficient evaluation of the θMDA are investigated, and we integrate them into concrete evaluation algorithms and provide cost formulas. An empirical evaluation with data from the TPC-H benchmark confirms the scalability of the θMDA operator and shows performance improvements of up to one order of magnitude over equivalent SQL implementations. © 2010 Elsevier B.V. All rights reserved.

Holmstrm L.,University of Oulu | Pasanen L.,University of Oulu | Furrer R.,University of Zrich | Sain S.R.,U.S. National Center for Atmospheric Research
Computational Statistics and Data Analysis | Year: 2011

A method to capture the scale-dependent features in a random signal is proposed with the main focus on images and spatial fields defined on a regular grid. A technique based on scale space smoothing is used. However, while the usual scale space analysis approach is to suppress detail by increasing smoothing progressively, the proposed method instead considers differences of smooths at neighboring scales. A random signal can then be represented as a sum of such differences, a kind of a multiresolution analysis, each difference representing details relevant at a particular scale or resolution. Bayesian analysis is used to infer which details are credible and which are just artifacts of random variation. The applicability of the method is demonstrated using noisy digital images as well as global temperature change fields produced by numerical climate prediction models. © 2011 Elsevier B.V. All rights reserved.

Borsig L.,University of Zrich
Progress in Molecular Biology and Translational Science | Year: 2010

Heparin is frequently used in the treatment of cancer-associated thromboembolism. Accumulating clinical evidence indicates that cancer patients treated with unfractionated and low-molecular weight heparin (LMWH) survive longer than patients treated by other anticoagulants, especially patients in the early stage of the disease. Experimental analysis from a number of animal models constantly provides evidence for the ability of heparin to attenuate metastasis. The non-anticoagulant activity of heparin on metastasis includes the ability to inhibit cellcell-interaction through blocking of P- and L-selectin, to inhibit extracellular matrix protease heparanase, and to inhibit angiogenesis. This chapter summarizes current experimental evidence on the biology of heparin during cancer progression, with the focus on potential mechanism of heparin antimetastatic activity. © 2010 Elsevier Inc. All rights reserved.

O'Mahony L.,University of Zrich | Akdis M.,University of Zrich | Crameri R.,University of Zrich | Akdis C.A.,University of Zrich
Autoimmunity | Year: 2010

The immune response is a tightly regulated process, which normally results in protection from infection and tolerance of innocuous environmental antigens. However, in allergic disease, the activated immune response results in a chronic pro-inflammatory state characterized by antibody secretion (IgE) and T cell activation to normally well-tolerated antigens. Currently, the treatment of allergic disease is focused on the suppression of key inflammatory mediators or inflammatory cell populations and include anti-histamines, anti-leukotrienes, β2 adrenergic receptor agonists and corticosteroids. However, these approaches only provide a temporary suppression of disease symptoms. Successful long-term treatment can only be provided by allergen-specific immunotherapy (allergen-SIT), which restores normal immunity against allergens. This review will discuss novel approaches to the management of allergy and asthma by targeting the T regulatory cell via modulation of the commensal microbiota and allergen-SIT. © 2010 Informa UK, Ltd.

Hitzler I.,University of Zrich | Oertli M.,University of Zrich | Becher B.,University of Zürich | Agger E.M.,Statens Serum Institute | Muller A.,University of Zrich
Gastroenterology | Year: 2011

Background & Aims: Immunization against the gastric bacterium Helicobacter pylori could prevent many gastric cancers and other disorders. Most vaccination protocols used in preclinical models are not suitable for humans. New adjuvants and a better understanding of the correlates and requirements for vaccine-induced protection are needed to accelerate development of vaccines for H pylori. Methods: Vaccine-induced protection against H pylori infection and its local and systemic immunological correlates were assessed in animal models, using cholera toxin or CAF01 as adjuvants. The contribution of B cells, T-helper (Th)cell subsets, and dendritic cells to H pylorispecific protection were analyzed in mice. Results: Parenteral administration of a whole-cell sonicate, combined with the mycobacterial cell-wallderived adjuvant CAF01, protected against infection with H pylori and required cell-mediated, but not humoral, immunity. The vaccine-induced control of H pylori was accompanied by Th1 and Th17 responses in the gastric mucosa and in the gut-draining mesenteric lymph nodes; both Th subsets were required for protective immunity against H pylori. The numbers of memory CD4 + T cells and neutrophils in gastric tissue were identified as the best correlates of protection. Systemic depletion of dendritic cells or regulatory T cells during challenge infection significantly increased protection by overriding immunological tolerance mechanisms activated by live H pylori. Conclusions: Parenteral immunization with a Helicobacter vaccine using a novel mycobacterial adjuvant induces protective immunity against H pylori that is mediated by Th1 and Th17 cells. Tolerance mechanisms mediated by dendritic cells and regulatory T cells impair H pylori clearance and must be overcome to improve immunity. © 2011 AGA Institute.

Itten B.,University of Zrich | Honegger R.,University of Zrich
Lichenologist | Year: 2010

The genetic diversity within and among populations of Xanthoria parietina was studied at the subspecific level with a fingerprinting technique (RAPD-PCR) applied to sterile cultured multispore isolates, each being derived from a single apothecium. Populations from coastal, rural and urban sites from NW, SW and central France and from NE Switzerland were investigated. Between 1 and 8 microsites of a few decimetres square, each comprising 13 to 27 thalli of X. parietina, were analysed per population. A total of 132 isolates from epiphytic and 3 isolates from epilithic specimens were investigated. Phenotypic variation was recorded among some of the thalli in the field and among sterile cultured isolates in the laboratory. A high diversity of genotypes was observed, even among thalli growing side by side in phenotypically homogenous populations. An average of 735 % polymorphism was found in all samples. As shown with Principal Coordinates Analysis (PCO), most of the genetic variation (90%) resided within, not among, populations. As X. parietina had previously been shown with molecular and fingerprinting techniques to be homothallic, the potential genetic background of this diversity is discussed. Intense genotype rather than gene (allele) flow seems to be an important element in X. parietina populations. © 2010 British Lichen Society.

PubMed | University of Lausanne, Laboratory of Biomechanical Orthopedics and University of Zrich
Type: | Journal: Cell transplantation | Year: 2016

The potential of human fetal bone cells for successful bone regeneration has been shown in vivo. Inparticular, it has been demonstrated that the seeding of these cells in porous poly-(L-lactic acid)/ ß-tricalcium phosphate scaffolds improved the bone formation compared to cell-free scaffolds in skulls of rats. However, even if the outcome is an improvement of bone formation, a thorough analysis concerning any immune responses, due to the implantation of a xenograft tissue, is not known. As the immune response and skeletal system relationship may either contribute to success or failure of an implant, we were interested in evaluating the presence of any immune cells and specific reactions of human fetal cells (also called human bone progenitor cells) once implanted in femoral condyles of rats. For this purpose (1) cell-free scaffolds, (2) human bone progenitor cells or (3) osteogenic human bone progenitor cells within scaffolds were implanted over 3, 7, 14 days and 12 weeks. The key finding is that human bone progenitor cells and osteogenic human bone progenitor cells do not trigger any particular specific immune reactions in immuno-competent rats, but are noted to delay some bone formation.

Loading University of Zrich collaborators
Loading University of Zrich collaborators