Der Einfluss der Sohlendicke auf die Thermoisolation der Hornkapsel beim Equiden

Lameness that appears after hot-shoeing is an issue the farrier is often blamed for. The aim of this study was to investigate the thickness of the sole at which it is possible to measure a change in temperature within the hoof capsule. In addition it was aimed to measure what change in temperature causes damage to the corium of the sole. The front limbs of 20 horses, aged between 2 and 17 years old and of differing breed and size, were cut off at the carpal joint immediately after euthanasia. The experiment involved a simulation of routine conditions during hot-shoeing such as fitting the shoe on the hoof by branding. Branding was continued until a significant change in temperature was observed. The temperature described as “critical” in histological studies so far (51 degrees C with a branding time of 3 minutes) was achieved with a with a sole diameter of x - < 5.4 mm (s = ± 1, 5 mm). Damage to the tissue (extravasation, change in structure such as deformation of the cells and their nuclei) was found during histological examination of these samples which were taken from the sole with a diameter of 4 mm or less. The k- parameter of the horn analysed by the flash-method was 0,2 W / K*m, which means Horn has a very poor thermal conductivity. The well-known, highly effective thermo-isolating characteristic of the horn capsule was confirmed. Only when a sole has a thickness of x - < 5.4 irreversible thermal damage can occur when performing an excessively hot and long-lasting branding. In this way the results can help to answer questions in the area of forensic medicine. Therefore it is of great importance to perform adequate x-rays (perpendicular course of beam; labelling of the sole) in order to document the (actual) thickness of the sole after branding and the following occurrence of lameness. By measuring the thickness of the sole it can be told whether there is a possibility that damages on the corium may have been caused by hot-shoeing, at all, and thereby also tell the probability of this to occur.Lahmheiten, die nach einem Heißbeschlag auffallen, werden häufig dem Hufschmied zur Last gelegt. Ziel der vorliegenden Studie war es, die Sohlendicke zu bestimmen, bei der zwischen Lederhaut und Hornkapsel eine Temperaturveränderung messbar wird und ab der sich auch Gewebeschäden an der Sohlenlederhaut einstellen. Von 20 Pferden unterschiedlicher Rasse und Größe im Alter zwischen 2 und 17 Jahren wurden jeweils beide Vordergliedmaßen unverzüglich nach der Euthanasie im Karpalgelenk abgesetzt und an den Hufen wurden die beim Hufbeschlag üblichen Bedingungen des Aufbrennens des Eisens simuliert. Begleitend wurde die Temperaturveränderung im Inneren der Hornkapsel gemessen. Die Temperatur von 51°C, bei der mit ersten Gewebeschäden zu rechnen ist, wurde erst bei einer Sohlendicke von x -< 5,4 mm erreicht. Eine Schädigung des Gewebes (Extravasation, Veränderungen der Struktur bzw. Deformation der Zellen und deren Kerne) zeigte sich bei den histologischen Untersuchungen erst bei einer Sohlendicke von weniger als 4 mm. Der k-Wert von Horn, gemessen mit der Flash - Methode, betrug ca. 0,2 W / K*m. Das Hufhorn weist somit eine sehr schlechte Wärmeleitfähigkeit auf. Die bekannten, höchstgradig effektiven thermoisolierenden Eigenschaften der Hornkapsel wurden bestätigt: Erst ab einer Sohlendicke von x -< 5,4 mm kann bei übertrieben heißem und langem Aufbrennen überhaupt eine irreversible thermische Schädigung der Lederhaut entstehen. Voraussetzung für die Beurteilung der Sohlendicke nach einem Hufbeschlag mit anschließend festgestellter Lahmheit ist, dass zeitnah nach dem Beschlag und dem Auftreten einer Lahmheit durch eine geeignete Röntgenuntersuchung mit orthogradem Strahlengang und Markierung der Sohle die Sohlendicke dokumentiert wird. Anhand der Sohlendicke kann dann beurteilt werden, ob überhaupt eine Verbrennung der Lederhaut beim Hufbeschlag möglich war und wie hoch die Wahrscheinlichkeit dafür ist, dass eine Verbrennung stattgefunden hat

In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis

Equine recurrent uveitis (ERU) causes painful inflammatory attacks and oftentimes blindness in the affected eyes. The disease is considered a late sequela of systemic leptospirosis. The most effective therapy is the surgical removal of the vitreous (vitrectomy), which is not only therapeutic, but provides vitreous material that can be assessed diagnostically. For example, the lipL32 gene, culturable Leptospira spp., and anti-Leptospira antibodies have all been detected in vitreous samples obtained from eyes with chronic ERU. Despite this clear evidence of leptospiral involvement, the systemic administration of antibiotics in infected horses is ineffective at resolving ERU. This syndrome of chronic recurrent inflammation, which is unresponsive to antibiotic therapy, combined with apparent bacteria evading the immune response, is consistent with a biofilm-associated infection. The purpose of this study, therefore, was to detect the in vivo biofilm formation of Leptospira spp. in vitreous samples collected during vitrectomy and examined using a Warthin-Starry silver stain and immunohistochemistry. All known steps of biofilm formation were visualized in these samples, including individual Leptospira spp., leptospiral microcolonies and dense roundish accumulations of Leptospira spp. In many instances spirochetes were surrounded by an extracellular substance. Taken together, data from the present study show that ERU is a biofilm-associated intraocular leptospiral infection, which best explains the typical clinical course

The ox-foot-model for investigating endoluminal thermal treatment modalities of varicosis vein diseases

The introduction of technical surgical innovations in clinical medicine is preceded by preclinical evaluation of prototypes. Surgical aspects such as energy dependent tissue response and tissue sealing to reduce bleeding are usually investigated in animal experiments. Extra-corporal organ models can provide the required experimental information without harming animals and thus reduce or even replace in vivo experiments. Here we describe the ex vivo ox-foot-model, which can be used for surgical investigations and for training purposes. In the ox-foot-model the vein remains in its anatomical bed under reproducible experimental conditions, i.e., blood perfusion, blood pressure, and temperature. Innovative endoluminal surgical procedures using laser light and radio frequency for varicosis treatment were tested. Treatment parameters were investigated systematically in a large number of samples. A standardized preclinical testing procedure could be established and optimized on the basis of acute macroscopic and histological findings. Further, optical coherence tomography could be evaluated as a time-saving diagnostic tool. The ox-foot-model is suitable for training surgical techniques relevant for the treatment of varicosis veins. It is a cost-effective alternative to conventional in vivo experiments, providing standardized experimental conditions and reproducible experimental results while respecting the Principles of Humane Experimental Techniques: Reduction, Refinement, and Replacement of animal experiments

The ox-foot-model for investigating endoluminal thermal treatment modalities of varicosis vein diseases

The introduction of technical surgical innovations in clinical medicine is preceded by preclinical evaluation of prototypes. Surgical aspects such as energy dependent tissue response and tissue sealing to reduce bleeding are usually investigated in animal experiments. Extra-corporal organ models can provide the required experimental information without harming animals and thus reduce or even replace in vivo experiments. Here we describe the ex vivo ox-foot-model, which can be used for surgical investigations and for training purposes. In the ox-foot-model the vein remains in its anatomical bed under reproducible experimental conditions, i.e., blood perfusion, blood pressure, and temperature. Innovative endoluminal surgical procedures using laser light and radio frequency for varicosis treatment were tested. Treatment parameters were investigated systematically in a large number of samples. A standardized preclinical testing procedure could be established and optimized on the basis of acute macroscopic and histological findings. Further, optical coherence tomography could be evaluated as a time-saving diagnostic tool. The ox-foot-model is suitable for training surgical techniques relevant for the treatment of varicosis veins. It is a cost-effective alternative to conventional in vivo experiments, providing standardized experimental conditions and reproducible experimental results while respecting the Principles of Humane Experimental Techniques: Reduction, Refinement, and Replacement of animal experiments

Accuracy of conventional radiography and computed tomography in predicting implant position in relation to the vertebral canal in dogs.

OBJECTIVE To compare the accuracy of radiography and computed tomography (CT) in predicting implant position in relation to the vertebral canal in the cervical and thoracolumbar vertebral column. STUDY DESIGN In vitro imaging and anatomic study. ANIMALS Medium-sized canine cadaver vertebral columns (n=12). METHODS Steinmann pins were inserted into cervical and thoracolumbar vertebrae based on established landmarks but without predetermination of vertebral canal violation. Radiographs and CT images were obtained and evaluated by 6 individuals. A random subset of pins was evaluated for ability to distinguish left from right pins on radiographs. The ability to correctly identify vertebral canal penetration for all pins was assessed both on radiographs and CT. Spines were then anatomically prepared and visual examination of pin penetration into the canal served as the gold standard. RESULTS Left/right accuracy was 93.1%. Overall sensitivity of radiographs and CT to detect vertebral canal penetration by an implant were significantly different and estimated as 50.7% and 93.4%, respectively (P<.0001). Sensitivity was significantly higher for complete versus partial penetration and for radiologists compared with nonradiologists for both imaging modalities. Overall specificity of radiographs and CT to detect vertebral canal penetration was 82.9% and 86.4%, respectively (P=.049). CONCLUSIONS CT was superior to radiographic assessment and is the recommended imaging modality to assess penetration into the vertebral canal. CLINICAL RELEVANCE CT is significantly more accurate in identifying vertebral canal violation by Steinmann pins and should be performed postoperatively to assess implant position