Prospektive Untersuchungen zu pathologisch–anatomischen Befunden bei Kühen mit perforierendem Labmagengeschwür

Ziel der vorliegenden Arbeit war die detaillierte Beschreibung von Anzahl, Lokalisation, Morphologie und Perforationwegen von perforierenden Labmagengeschwüren bei der Kuh. In einer vorgeschalteten retrospektiven Studie wurden die Selektionskriterien für diese Untersuchung erarbeitet. Die Mehrzahl der Patienten waren Rinder der Rasse Deutsches Fleckvieh mit einem Alter zwischen zwei und vier Jahren. Bei den sieben Kühen mit Typ III- Geschwüren (lokal begrenzte Peritonitis) und 16 Kühen mit Typ IV- Geschwüren (generalisierte Peritonitis) dieser Untersuchung lagen alle Perforationen im Korpus des Labmagens. Die Mehrzahl (n=11) der perforierenden Geschwüre vom Typ IV (generalisierte Peritonitis) lag im Pylorusregion-nahen Drittel des Korpus. Bei vier Tieren befand sich die Perforation im „mittleren Drittel“ des Korpus. Bei nur einem Tier mit Typ IV-Geschwür lag die Perforation im Psalter-nahen Drittel. Häufig lagen die Perforationen in den ventralen Labmagenbereichen. So waren bei 13 Patienten die perforierenden Geschwüre in dem Bereich der großen Kurvatur bis zum zentralen Labmagen lokalisiert. Bezüglich der Lokalisation der Geschwüre vom Typ III (lokal begrenzte Peritonitis) konnte keine Häufung innerhalb der Korpusregionen gefunden werden. Die Typ III-Geschwüre traten häufig gleichzeitig mit einer Labmagenverlagerung auf. Meist war nur ein perforierendes Geschwür pro Labmagen zu finden. In nur einem Fall waren zwei perforierende Geschwüre zu finden. Bei zwei Tieren konnte ein Geschwür mit zwei beziehungsweise vier Perforationen nachgewiesen werden. Die Morphologie der Geschwüre war meist oval bis rund mit wallartig aufgeworfenen Rändern. Die Geschwüre hatten meist eine Größe von einem bis vier Zentimeter(n). Bei allen Tieren mit Typ IV-Geschwüren erfolgte die Perforation in der Facies parietalis. Bei den Probanden mit Typ III-Geschwüren war nur einmal eine Perforation in der Facies visceralis zu finden. Hier erfolgte die Perforation also in die Bursa omentalis. Häufig konnte in der Bauchhöhle grün-sulziges Fibrin gefunden werden

Orienting lignocellulosic fibers by means of a magnetic field

Controlling the orientation and spatial distribution of discontinuous fibers in composite materials enables product properties to be tailored to anticipated use. Electric fields are already (albeit rarely) used to affect alignment in lignocellulosic (LC) fiber composites. The use of magnetic fields has not, however, been suggested or explored; this is apparently because LC fibers are essentially non-magnetic. The approach may offer, however, some considerable advantages, as long as ferromagnetism may be imparted to the fibers. In the present research several fiber modification processes were considered and two, electroless nickel plating and spray application of a coating containing nickel in suspension, were investigated in more depth. The latter was chosen to render highly engineered, elongated wood particles responsive to magnetic fields. Individual treated particles were suspended in viscous, newtonian silicone fluids and their rotation under the influence of a controlled magnetic field was video recorded. The magnetic torque on the particle was, under the above conditions, directly proportional to the fluid viscosity, to the particle's angular velocity and to a characteristic shape constant. The maximum of the specific magnetic torque (magnetic torque divided by the shape constant) was found to reflect the influence of field strength and particle Ni-treatment on rotation. Results were scaled to an arbitrarily chosen viscosity for comparison. The dependencies of the magnetic torque found in the present research compare with those theoretically predicted for ellipsoidal and cylindrical bodies. For field strengths ranging from 0.07T to 0.15T (below magnetic saturation) the magnetic torque increased almost linearly with increasing field strength. Magnetic torque was also found to increase nearly linearly with increasing bulk Ni-concentration (5g/kg - 50g/kg). Rotational motion was sometimes impeded at low field strengths and this was attributed to a permanent magnetic moment obtained by the particle. A coercive field strength of 7600A/m supported this hypothesis. Judiciously switched field polarity increased magnetic torque at small alignment angles. The present research indicates that orienting LC fibers with magnetic fields is possible and promising. To study dynamics of fiber motion in low viscosity fluids, such as air, a different experimental method is necessary; however, dependencies of the magnetic torque found in the present study still hold true

Interaction of Proteins with a Planar Poly(acrylic acid) Brush: Analysis by Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D)

We describe the preparation of a poly(acrylic acid) (PAA) brush, polymerized by atom transfer radical polymerization (ATRP) of tert-butyl acrylate (tBA) and subsequent acid hydrolysis, on the flat gold surfaces of quartz-crystal microbalance (QCM) crystals. The PAA brushes were characterized by Fourier transform infrared (FT-IR) spectroscopy, ellipsometry and water contact angle analysis. The interaction of the PAA brushes with human serum albumin (HSA) was studied for a range of ionic strengths and pH conditions by quartz-crystal microbalance with dissipation monitoring (QCM-D). The quantitative analysis showed a strong adsorption of protein molecules onto the PAA brush. By increasing the ionic strength, we were able to release a fraction of the initially bound HSA molecules. This finding highlights the importance of counterions in the polyelectrolyte-mediated protein adsorption/desorption. A comparison with recent calorimetric studies related to the binding of HSA to polyelectrolytes allowed us to fully analyze the QCM data based on the results of the thermodynamic analysis of the binding process

Biodegradation of two commercial herbicides (Gramoxone and Matancha) by the bacteria Pseudomonas putida

The purpose of this project was to evaluate the biodegradation of two commercial herbicides (Gramoxone and Matancha) by the bacteria Pseudomonas putida . Gramoxone's active ingredient is Paraquat (1,1'-dimethyl-4,4'-bipyridylium) and Matancha's is 2,4-D (2,4-dichlorophenoxiacetic acid). To carry out the biodegradation experiments, a factorial design 23 was executed, where the independent variables were: herbicide concentration, nutrient concentration and the use or no use of activated charcoal (AC) in the same experiment with bacteria. Duplicate experiments were performed for a period of three days using 500 ml bioreactors. The best results obtained when no AC was used were: 47,29% degradation for Gramoxone (by UV/VIS) and 68.72% for Matancha (by HPLC). The treatments carried out with the use of AC for either of the two herbicides gave more than 95% degradation at 72 h. In fact, under these conditions most of the experiments showed at least a 90% removal at 24 h. It is clear that the dual combination of adsorption by AC and biological activity by the bacteria was very effective, in particular when at least 10% nutrients were added. The statistical study of the results showed that AC is a highly significant variable, and that there are significant interactions between the three variables used in the experimental design. The application of these experiments to wastewater (COD = 584.11) confirmed that it is possible to remove more than 90% of either of these herbicides in a 24 h period

Large-Scale microRNA Expression Profiling Identifies Putative Retinal miRNA-mRNA Signaling Pathways Underlying Form-Deprivation Myopia in Mice

Development of myopia is associated with large-scale changes in ocular tissue gene expression. Although differential expression of coding genes underlying development of myopia has been a subject of intense investigation, the role of non-coding genes such as microRNAs in the development of myopia is largely unknown. In this study, we explored myopia-associated miRNA expression profiles in the retina and sclera of C57Bl/6J mice with experimentally induced myopia using microarray technology. We found a total of 53 differentially expressed miRNAs in the retina and no differences in miRNA expression in the sclera of C57BL/6J mice after 10 days of visual form deprivation, which induced -6.93 ± 2.44 D (p < 0.000001, n = 12) of myopia. We also identified their putative mRNA targets among mRNAs found to be differentially expressed in myopic retina and potential signaling pathways involved in the development of form-deprivation myopia using miRNA-mRNA interaction network analysis. Analysis of myopia-associated signaling pathways revealed that myopic response to visual form deprivation in the retina is regulated by a small number of highly integrated signaling pathways. Our findings highlighted that changes in microRNA expression are involved in the regulation of refractive eye development and predicted how they may be involved in the development of myopia by regulating retinal gene expression

Peptide-PEG Amphiphiles as Cytophobic Coatings for Mammalian and Bacterial Cells

SummaryAmphiphilic macromolecules containing a polystyrene-adherent peptide domain and a cell-repellent poly(ethylene glycol) domain were designed, synthesized, and evaluated as a cytophobic surface coating. Such cytophobic, or cell-repellent, coatings are of interest for varied medical and biotechnological applications. The composition of the polystyrene binding peptide domain was identified using an M13 phage display library. ELISA and atomic force spectroscopy were used to evaluate the binding affinity of the amphiphile peptide domain to polystyrene. When coated onto polystyrene, the amphiphile reduced cell adhesion of two distinct mammalian cell lines and pathogenic Staphylococcus aureus strains

Mechanical Properties and Gene Expression of Chondrocytes on Micropatterned Substrates Following Dedifferentiation in Monolayer

Chondrocytes in articular cartilage normally exhibit high expression of collagen II and aggrecan but rapidly dedifferentiate to a fibroblastic phenotype if passaged in culture. Previous studies have suggested that the loss of chondrocyte phenotype is associated with changes in the structure of the F-actin cytoskeleton, which also controls cell mechanical properties. In this study, we examined how dedifferentiation in monolayer influences the mechanical properties of chondrocytes isolated from different zones of articular cartilage. Atomic force microscopy was used to measure the mechanical properties of superficial and middle/deep zone chondrocytes as they underwent serial passaging and subsequent growth on fibronectin-coated, micropatterned self-assembled monolayers (MSAMs) that restored a rounded cell shape in 2D culture. Chondrocytes exhibited significant increases in elastic and viscoelastic moduli with dedifferentiation in culture. These changes were only partially ameliorated by the restoration of a rounded shape on micropatterned surfaces. Furthermore, intrinsic zonal differences in cell mechanical properties were rapidly lost with passage. These findings indicate that cell mechanical properties may provide additional measures of phenotypic expression of chondrocytes as they undergo dedifferentiation and possibly redifferentiation in culture

Teaching Protein Crystallization by the Gel Acupuncture Method

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Altered Trabecular Bone Structure and Delayed Cartilage Degeneration in the Knees of Collagen VI Null Mice

Mutation or loss of collagen VI has been linked to a variety of musculoskeletal abnormalities, particularly muscular dystrophies, tissue ossification and/or fibrosis, and hip osteoarthritis. However, the role of collagen VI in bone and cartilage structure and function in the knee is unknown. In this study, we examined the role of collagen VI in the morphology and physical properties of bone and cartilage in the knee joint of Col6a1−/− mice by micro-computed tomography (microCT), histology, atomic force microscopy (AFM), and scanning microphotolysis (SCAMP). Col6a1−/− mice showed significant differences in trabecular bone structure, with lower bone volume, connectivity density, trabecular number, and trabecular thickness but higher structure model index and trabecular separation compared to Col6a1+/+ mice. Subchondral bone thickness and mineral content increased significantly with age in Col6a1+/+ mice, but not in Col6a1−/− mice. Col6a1−/− mice had lower cartilage degradation scores, but developed early, severe osteophytes compared to Col6a1+/+mice. In both groups, cartilage roughness increased with age, but neither the frictional coefficient nor compressive modulus of the cartilage changed with age or genotype, as measured by AFM. Cartilage diffusivity, measured via SCAMP, varied minimally with age or genotype. The absence of type VI collagen has profound effects on knee joint structure and morphometry, yet minimal influences on the physical properties of the cartilage. Together with previous studies showing accelerated hip osteoarthritis in Col6a1−/− mice, these findings suggest different roles for collagen VI at different sites in the body, consistent with clinical data