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

Chronic Intraocular Leptospiral Infection Relying on Biofilm Formation inside the Vitreous Cavity Leads to Recurrent Uveitis in Horses

Equine recurrent uveitis (ERU) is a disease known and feared for centuries, as it almost always leads to blindness even with careful and meticulous conservative treatment of the individual episodes of uveitis. In about one-third of horses, both eyes are affected, often necessitating euthanasia. A link between ERU and leptospiral infection has been suspected for nearly 80 years. Vitreous lavage (vitrectomy) can preserve vision in affected eyes. After surgery, no further episodes of uveitis occur in up to more than 95% of operated eyes. With routine performance of vitrectomies, numerous vitreous samples could be used for further investigations. Intraocular anti-Leptospira antibody production was proven, leptospires could be cultured from the vitreous samples, and the LipL32 gene could be detected in the vitreous samples by PCR. Thus, there was convincing evidence of a chronic intraocular leptospiral infection, which can be eliminated most reliably by vitrectomy. Recently, it has been shown that the intraocular leptospires produce biofilm in the equine vitreous. Biofilm formation explains not only the success of vitrectomy, but also the survival of leptospires in the vitreous cavity for many years despite the presence of high intraocular antibody titers and immunocompetent cells, as well as the high tolerance to antibiotics

Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp.

Equine recurrent uveitis (ERU) is typically caused by chronic intraocular leptospiral infection in warm-blooded horses in central Europe. The most effective therapy for leptospiral-induced ERU is the surgical removal of diseased vitreous (vitrectomy). Since vitrectomy is a highly specialized and invasive surgery, the indication must be determined very carefully. In order to obtain evidence of intraocular leptospiral infection by laboratory diagnostics in questionable leptospiral ERU-cases, sampling of aqueous humor is required, because serum tests using microscopic agglutination test (MAT) are too unspecific. The SNAP Lepto is a cross-species rapid test for the detection of anti-Lipl32 antibodies that has a high sensitivity (0.97) and specificity (1.00) for the detection of anti-leptospiral antibodies using aqueous humor or vitreous samples, which is comparable to MAT. To evaluate sensitivity and specificity of SNAP Lepto using serum, serum samples from 90 horses with confirmed leptospiral ERU and from 103 ocularly healthy horses were tested by both MAT and SNAP Lepto. Sensitivity was similar for both tests (0.82 vs. 0.79), but specificity was lower for MAT (0.52 vs. 0.95). Sensitivity and specificity are therefore lower in serum samples compared to intraocular samples, however, the SNAP Lepto is far superior to MAT and suitable as a screening method using equine serum

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis

Uveitis is a sight-threatening eye disease in equids known worldwide that leads to considerable pain and suffering. By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses. Other infectious causes are extremely rare and are usually clinically distinguishable from ERU. ERU can be treated very effectively by vitreous cavity lavage (vitrectomy). For proper indications of this demanding surgery, it is necessary to differentiate ERU from other types of uveitis in which vitrectomy is not helpful. This can be conducted on the basis of anamnesis in combination with ophthalmologic findings and by aqueous humor examination. During vitrectomy, vitreous material is obtained. These vitreous samples have historically been used for numerous etiologic studies. In this way, a chronic intraocular leptospiral infection has been shown to be the cause of typical ERU and, among other findings, ERU has also been recognized as a biofilm infection, providing new insights into the pathogenesis of ERU and explaining some thus far unexplainable phenomena of ERU. ERU may not only have transmissible aspects to some types of uveitis in humans but may also serve as a model for a spontaneously occurring biofilm infection. Vitreous material obtained during therapeutically indicated vitrectomy can be used for further studies on in vivo biofilm formation, biofilm composition and possible therapeutic approaches

Analysis of 1840 Equine Intraocular Fluid Samples for the Presence of Anti-Leptospira Antibodies and Leptospiral DNA and the Correlation to Ophthalmologic Findings in Terms of Equine Recurrent Uveitis (ERU)&mdash;A Retrospective Study

In the equine clinic of the LMU in Munich, therapeutic vitrectomies have been routinely performed in horses for three decades. The vitreous samples obtained during vitrectomies were usually tested for anti-Leptospira antibodies and for more than 20 years also by PCR for leptospiral DNA. If the indication for surgery was ophthalmologically inconclusive, an aqueous humor was collected preoperatively and examined for evidence of leptospiral infection. In this study, medical records from 2002 to 2017 were analyzed. Records for 1387 eyes affected by equine recurrent uveitis (ERU) and 237 eyes affected by another type of uveitis met the inclusion criteria. A total of 216 samples from healthy eyes were used as controls. In 83% of intraocular samples from ERU eyes, antibody titers of 1:100 or higher were detectable by microscopic agglutination test (MAT). Similarly, 83% of intraocular samples had anti-Leptospira antibodies detected by ELISA. In 72% of the intraocular specimens, leptospiral DNA was detectable by PCR. No antibodies were detectable in the samples from eyes with another type of uveitis or in the samples from healthy eyes. A PCR was positive in only one sample from a healthy eye. These results with a very high number of intraocular specimens demonstrate the great importance of an intraocular leptospiral infection for ERU. It can be concluded that for a reliable diagnosis of intraocular leptospiral infection or to reliably exclude an infection multiple tests should be applied

Immune responses to retinal autoantigens and peptides in equine recurrent uveitis

PURPOSE. To test the hypothesis that autoimmune mechanisms are involved in horses in which equine recurrent uveitis (ERU) develops spontaneously. METHODS. Material obtained from horses treated for spontaneous disease by therapeutic routine vitrectomy was analyzed for total IgG content and IgG specific for S-Antigen (S-Ag) and interphotoreceptor retinoid-binding protein (IRBP). The cellular infiltrate of the vitreous was analyzed by differential counts of cytospin preparations and flow cytometry using equine lymphocyte-specific antibodies. Antigen-specific proliferation assays were performed comparing peripheral blood lymphocytes (PBLs) with vitreal lymphocytes by stimulation with S-Ag and several S-Ag-and IRBP-derived peptides. RESULTS. The total IgG content of specimens from horses with ERU was very high with great variability among the investigated samples (11.5 Ϯ 8.0 mg). Autoantibodies to S-Ag or IRBP or both were found in 72% of vitreous specimens from horses with uveitis. The leukocyte infiltrates (up to 2 ϫ 10 8 cells per sample) were dominated by lymphocytes (Ͼ90%) in most cases (22/32). Flow cytometry showed that more than 50% of these cells were CD4 ϩ T cells. In vitro stimulation of vitreal lymphocytes, but not of PBL, showed a strong proliferative response to peptides derived from S-Ag or IRBP in 9 of 12 patients. CONCLUSIONS. In the eyes of horses with ERU, IgG antibodies and autoreactive T cells specific for retinal antigens were detected. These results strongly support the hypothesis that ERU is an autoimmune-mediated disease and is highly similar to recurrent uveitis in humans in both clinical and immunologic parameters. (Invest Ophthalmol Vis Sci. 2001;42:393-398