In vitro effects of fungi isolated from equine hooves on primary human keratinocytes

The effects of two dermatophytes (Microsporum gypseum and Trichophyton mentagrophytes) and four moulds (Scopulariopsis brevicaulis, Alternaria alternata, Geotrichum candidum and Penicillium spp.) on living keratinocyte cultures were examined in vitro using primary human keratinocytes. Rates of apoptosis of infected cells were determined using a colorimetric TUNEL system which detects the characteristic nuclear DNA fragmentation of apoptotic cells. The cytotoxicity of the individual fungi was tested by quantitatively measuring cytosolic enzyme lactate dehydrogenase, released upon cell lysis, in culture supernatants. Additionally, the cell structures within the infected keratinocytes in cultures were examined by scanning electron microscopy. All of the fungi exhibited high cytotoxicity, whereas the development of only the two dermatophytes and the mould Scopulariopsis brevicaulis resulted in distinctly increased apoptosis. Electron microscopy showed that all fungi studied caused similar alterations in the cell structure, with Microsporum gypseum being the most harmful. Increasing loss of cell adhesion as a consequence of a decreasing number of reticulating cell appendices and a reduced cell plasticity were the most evident alterations.

In vitro degradation of equine keratin by dermatophytes and other keratinophilic fungi

Keratinolytic properties of two dermatophytes (Microsporum gypseum, Trichophyton mentagrophytes) and three moulds (Scopulariopsis brevicaulis, Alternaria alternata, Geotrichum candidum) isolated from diseased equine hooves were examined to improve the understanding of pathogenic mechanisms leading to equine onychomycosis. Equine hoof horn material and skin, as well as hoof keratin and dermal keratin extracted from corresponding tissues, were used as sole carbon and nitrogen sources in five test tubes for each fungus. Within 18 days, supernatants of all tubes were repeatedly examined for keratinolytic activity by SDS-PAGE and Western blot analysis. In addition, fungal growth rates were determined to identify the preferred tissue of the individual fungi. Among the fungi examined, M. gypseum was the most keratinolytic species, followed by T. mentagrophytes and S. brevicaulis. In the concentration applied, the moulds A. alternata and G. candidum showed minimal keratinolytic activity. With respect to growth rates, M. gypseum favoured hoof horn material, S. brevicaulis and G. candidum preferred skin as a keratin source, whereas for the other two fungi no clear preference was detectable.

Doppler sonographic evaluation of the digital blood flow in horses with laminitis or septic pododermatitis

The aim of this study was to evaluate the use of Doppler ultrasonography to monitor vascular blood flow dynamics in defined diseases of the equine digit in a noninvasive way. Doppler sonography was used to evaluate medial digital artery blood flow in eight horses with septic pododermatitis and four horses with laminitis in comparison with 10 horses of a control group. Doppler sonographic measurement and lameness examinations were performed in lame horses before treatment (day 0) and at 3, 6, and 9 days following treatment. Before treatment, blood flow velocities, arterial diameter, and flow volume were significantly higher in the lame horses, while pulsatility indices (PIs) were significantly lower (P < 0.05). Compared with the control group, there was no significant difference of resistive indices (RI) in the septic pododermatitis group, but these indices were significantly lower in the laminitis group. No significant difference between the two lame groups was recorded. After treatment, blood flow velocities and flow volume decreased significantly and PIs increased significantly in both lame groups, while RI and arterial diameter did not change. No correlation between Doppler parameters and the degree of lameness was found. Doppler sonography can be used to monitor vascular blood flow dynamics in horses suffering from septic pododermatitis and laminitis, while blood flow velocities and PI can serve as parameters for monitoring the course of the disease.

Emergence of MRSA infections in horses in a veterinary hospital: strain characterisation and comparison with MRSA from humans

Methicillin-resistant Staphylococcus aureus has become an emerging public health problem worldwide, no longer only associated with healthcare-associated infections. With the exception of some recent reports concerning infections in cats, dogs and horses, infections with MRSA in companion animals have been infrequently reported. Here we submit findings for MRSA infections in horses in a central European university hospital.

Emergence of MRSA infections in horses in a veterinary hospital: strain characterisation and comparison with MRSA from humans

Methicillin-resistant Staphylococcus aureus has become an emerging public health problem worldwide, no longer only associated with healthcare-associated infections. With the exception of some recent reports concerning infections in cats, dogs and horses, infections with MRSA in companion animals have been infrequently reported. Here we submit findings for MRSA infections in horses in a central European university hospital.

Slatted Floors and Solid Floors: Stress and Strain on the Bovine Hoof Capsule Analyzed in Finite Element Analysis

An established finite element model of a bovine claw was used to compare mechanical stress levels in a loaded model claw on different types of flooring. The following situations were compared: a claw standing on a solid floor, a claw standing on the edge of a short tie stand, and claws standing on slatted floors with slats of 28 and 40 mm (wide) running parallel and perpendicular to the claw axis. Finite element analysis allowed visualization of stress peaks seen predominantly in the weight-bearing border of the dorsal abaxial wall and of the bulbar region and in the proximal axial wall. Maximum stress values of 13 MPa were found in the model claw loaded on the solid floor and values of 18 to 22 MPa were seen in the model claw loaded on the edge of the solid floor. On slatted floors, stresses increased in the situation in which the claw was not supported under the abaxial wall. Comparison between the other slatted floors showed little difference in amounts of mechanical stress. A clear distinction was detected between the solid floor with full claw contact and the slatted floors. From the point of view of the mechanical stress seen in finite element analysis, a large contact area between claw and floor, as seen in the solid surface floor, is preferable. When use of slatted floors is unavoidable, direction of the slats should run perpendicular to the direction of the walkway to prevent even more mechanical impact in certain footing situations.

The hardness of horn in different segments of the bovine claw

Hardness of bovine hoof horn was tested as ball indentation hardness and as shore D hardness post mortem in different segments of the hoof wall, in the sole and the hard bulb of sound claws of 10 Austrian Holstein Friesian cows. Both methods of hardness determination showed corresponding results, with shore D hardness between 52.2 and 63.9 hardness units (hu) and ball indentation hardness between 11.2 N/mm2 and 24.3 N/mm2. Bovine hoof horn becomes significantly softer from the coronary band towards the weight bearing border (vertical decrease) and from the dorsal wall towards the heel (horizontal decrease). Decreasing hardness was associated with decreasing dry matter content. Measurements of the claw capsule showed thickness of the hoof wall increasing from the coronary border towards the sole. In dorsopalmar/-plantar direction, bovine hoof wall at the weight bearing border decreases towards the heel.

Elastic properties of hoof horn on different positions in the bovine claw

Hind claws of 15 adult, sound Fleckvieh cows were used for material analysis. The elastic modulus was tested in tension tests according to EN ISO 527 and ASTM D 638-03 at a universal material testing machine. Samples were taken from different segments of the bovine claw to find the differences in material properties. Samples orientation was parallel to the horn tubules and transversal, respectively. Dry matter of the test samples was determined at the time of testing. Elastic modulus values were highest with mean = 659.7 N/mm2 at the dorsal wall. Values dropped axial to 416.3 N/mm2, abaxial to 343.9 N/mm2 for longitudinal (parallel) samples and to 433.1 N/mm2 for transversal samples. The elastic modulus of the sole segment was found to be 172.1 N/mm2. No difference was calculated neither between right and left feet, lateral and medial claws, nor between longitudinal and transversal samples.

Comparison of computed radiography and conventional film-screen radiography of the equine stifle

Major advantages of computed radiography are the potential reduction of dose and the possibility of postprocessing. In our study, we compared conventional radiographs to digital radiographs of the equine stifle by subjective evaluation of diagnostic quality when using a decreasing photon flux (mAs). Twelve equine stifle joints from horses of different weight and size were examined. Conventional and digital radiographs were performed identically in a caudocranial projection with the tube angled 15 degrees. A series of four radiographs was performed in each technique with an increasing photon flux starting with 2.5 mAs and going up to 5, 10, and 20 mAs. All radiographs were evaluated subjectively in a blinded fashion by seven readers in terms of contrast, bone structure, and diagnostic value and were graded using a 1-5 scale. Results from conventional and digitized radiographs were compared, and differences between the individual observers were analyzed statistically. Contrast, bone structure, and diagnostic value from digital images were rated significantly better than from conventional images (p < .001). For both techniques, a decrease in ranking was found with a decrease of photon flux. There was only slight interobserver variability. A dose reduction up to a factor of 4 compared to a 100 speed film-screen system seems to be possible without loss of information. Weight and size of the horse are not major influences.

Ultrasonographic investigation of the atlanto-occipital articulation in the horse

The purpose of this study was to evaluate ultrasonographic imaging as a means of easy and noninvasive diagnosis of articular and periarticular structures of the atlanto-occipital articulation in the horse; and to find a safe approach to the atlanto-occipital joint. Ultrasonographic investigations were performed on 6 healthy horses and 16 specimens from horses humanely destroyed age 2-17 years (mean 9.56 years). Preliminary examinations included anatomical studies and preparation of cross-sections. On 4 horse specimens, puncture of the atlanto-occipital joint under ultrasonographic guidance was performed and a new lateral approach undertaken. For ultrasonographic investigations, the neck was divided into 4 zones according to anatomical and clinical modalities: 1) insertion of the funiculus nuchae; 2) tuberculum dorsale of the atlas; 3) atlanto-occipital joint and 4) region above the foramen alare. Each zone was examined in transverse and longitudinal planes proceeding from cranial to caudal. Ultrasonography was found to be useful for soft tissue imaging of this region and was performed down to the atlanto-occipital joint of which the joint surfaces, joint capsule and collateral ligament could be delineated in both planes. We conclude that ultrasonography of the neck is a useful technique, representing an easy to use and safe method. However, further studies are indicated which should be performed on live subjects.

Finite element analysis (FEA) as a model to predict effects of farriery on the equine hoof

A finite element (FE) hoof capsule was built as a small, symmetrical forelimb hoof on IDEAS* as a model for calculation and visualisation of stress and displacement of the equine hoof capsule. The model's loading was performed according to the suspension of the coffin bone within the hoof wall (pulling force) and over the sole and frog (compressing force) with a total of 3000 N. Restraints of the model's ground nodes and surface wall nodes were defined for simulation of 4 shoeing situations: a regular horseshoe, a horseshoe with a toe clip, a horseshoe with regular side clips and a horseshoe with a toe clip and more caudally-placed side clips, all fixed to the hoof capsule with 3 nails on each side and each calculated in a tense and a loose nailed condition. Von Mises stresses were taken ranging from 1.22 N/mm2 in the weightbearing border of the side clip shoe fixed loosely to the capsule up to 16.67 N/mm2 in the hoof horn material surrounding the third nail. Further high stress zones were calculated in the proximal dorsal wall, the distal heel and the lateral hoof wall. Displacement values were taken showing movements of hoof wall, sole and frog according to the shoeing conditions. Maximal displacement was calculated in the hoof capsule shod with a regular horseshoe without a clip. Minimal displacement was found in the capsule with a toe clip and 2 side clips placed behind the 3rd nail. All models showed higher displacements when calculated with a loose nail fixation. Validation of the detailed features of the models is not yet possible. Finite element analysis (FEA) can be used practically to predict influences of various farrier techniques on the equine hoof in order to avoid possible harm to horses' feet in field studies.

Keratinopathogenic mould fungi and dermatophytes in healthy and diseased hooves of horses

Specimens of hoof horn from 187 horses were examined for a possible relationship between clinically affected hooves and the occurrence of pathogenic fungi. Specimens were taken from the coronary band and from the stratum externum and medium of the coronary horn and transferred on to Sabouraud dextrose agar, with and without cycloheximide, and incubated at 28 degrees C. Dermatophytes and mould fungi were identified by their macroscopic and microscopic characteristics. The 732 isolates could be assigned to 26 species of moulds, two different species of the dermatophyte Microsporum and three different species of the dermatophyte Trichophyton. Depending on their pathogenic potential they were assigned to three groups: (i) fungi known to be keratinopathogenic (Acremonium blochii, Alternaria alternata, Alternaria chlamydospora, Geotrichum candidum, Microsporum ferrugineum, Microsporum gypseum, Scopulariopsis brevicaulis, Trichophyton species, Trichophyton mentagrophytes, Trichophyton schönleinii, 57 isolates), (ii) a group of uncertain pathogenicity (223 isolates), and (iii) a group of non-pathogenic species (452 isolates). Eighty per cent of the samples from horses with hoof horn lesions and 66.7 per cent of the samples from horses with slightly affected hoof horn contained fungi of the keratinopathogenic group, whereas only 8.9 per cent of the samples from horses with healthy hoof horn contained fungi of this group. There were no significant correlations between the clinical data and the age, sex or breed of the horses or their bedding and hygiene. Twelve species of fungi were isolated from the air in the horses' stables, but none of them belonged to the keratinopathogenic group.

Quality assurance in preoperative radiotherapy of rectal cancer: evaluation of a pre-trial dummy-run

PURPOSE

To assess inter-institution variability of treated volumes in preoperative radiotherapy for rectal cancer among Austrian radiotherapy institutions in the framework of a multi-centre phase-III clinical trial.

MATERIALS AND METHODS

All eleven Austrian radiotherapy departments were invited to participate in this pre-study dummy-run. They received a short history of two 'dummy patients' (case A and case B); three computer assisted tomography (CT) slices; simulation films; and the protocol describing the radiation technique to be used. Participants were asked to prepare a treatment plan for either case on the basis of the materials provided and to use their computerized planning systems. Additionally and independently of the CT-based treatment plans, they were asked to delineate the fields to be treated on the simulation films.

RESULTS

Nine of eleven departments participated. All participants used a three or four field technique as requested. The variation of beam widths and planning target volumes (PTVs) in the central plane was 6-11% and 11-16%, respectively. The standard deviations (SD) were 21 and 24% for the two cases for mean treated volumes of 2.1 and 2.9 l, respectively. The variation of beam widths in the central plane was less pronounced in the simulation based treatment plans as compared with the CT-based treatment plans for the dorsal fields, the opposite was true for the laterals.

CONCLUSION

Considerable variation of treated volumes is inevitable in multi-institution trials despite detailed treatment guidelines. Simulator based treatment fields seem to result in less pronounced inter-institution variations compared with CT-based treatment planning, if bony landmarks can be used as is the case in rectal cancer. Continuous quality control is thus warranted in multi-centre trials to increase homogeneity of volumes treated.

The effect of flat horseshoes, raised heels and lowered heels on the biomechanics of the equine hoof assessed by finite element analysis (FEA)

The biomechanical effects of lowering and raising the heels were studied using a finite element (FE) computer model of the equine hoof capsule consisting of 18,635 finite elements. A static load of 3000 N was distributed to nodes of the inner hoof wall (80%) according to the suspension of the coffin bone, 20% loaded sole and frog. When loaded the FE hoof capsules showed the following deformations: the proximal dorsal wall moves back, the quarters flare to the side and sole and frog perform a downward movement. Stresses are high in the material surrounding the quarter nails, in the heels and in the proximal dorsal wall. Three types of horseshoes were simulated, a regular shoe with flat branches, a shoe with 5 degrees raised heels and a shoe with 5 degrees lowered heels. Raising the heels resulted in significantly (P < 0.05) low stress and displacement values. The lowered heels model calculated highest stress and displacement values and the results of the FE model with the regular horseshoe were found in between.

[Use of tempered, particle-reinforced aluminum horse shoes in sport horses under field conditions]

The use of handmade particulate reinforced alloy horseshoes (MMC metal matrix composites) was tested in a field study on 15 riding and draught horses. All horseshoes have been tempered after having been manually forged and tested concerning their surface imperfection. Forging temperature ranged between 350 degrees and 420 degrees C. Horseshoes in series A consisted of particulate reinforced wrought alloy (22% Al2O3 in alloy matrix). 11 shoeing periods with a duration of mean = 49.7 days (sd = 13.6) were evaluated. Horseshoes in series B consisted of particulate reinforced foundry alloy (20% SiC in alloy matrix), 5 shoeing periods were evaluated with a duration of mean = 45.4 days (sd = 7.9). Series C tested horseshoes made of particulated reinforced coextruded wrought alloy evaluating 6 shoeing periods with a duration of mean = 49.2 days (sd = 18.7). Service of the tempered particulate reinforced alloy horseshoes was significantly higher compared to untempered alloy horseshoes. Mechanical and forging properties of tempered particulate reinforced alloy are satisfactory. Service is only suitable for riding horses but not for draught horses.

Evaluation of magnetic resonance imaging techniques in the equine digit

An anatomic study of the equine digit using magnetic resonance imaging (MRI) was performed. Seventeen isolated forelimbs and one hindleg of nine warmblood horses were imaged in transverse, sagittal, and dorsal planes with a 1.5 Tesla magnet using T1-, T2- proton density-weighted spin echo sequences as well as T2 gradient echo sequences. One scan plane in each horse was compared with corresponding anatomic and histologic sections. The best imaging planes to visualize various anatomic structures were determined. Fibrocartilage was visualized in the insertion of the deep digital flexor tendon and the suspensory ligament as well as in the distal sesamoidean ligaments. The correlation of MRI images with anatomic and histologic sections confirmed that all of the anatomic structures in the equine digit could be evaluated in PD and T2 studies.

[Use of sodium ceftiofur in the combined therapy of complicated septic diseases in cattle]

The use of Sodium-Ceftiofur (Excenel) with a dosage regimen of 1 mg/kg body mass intramuscularly was evaluated in the therapy of complicated claw diseases, like septic arthritis of the distal interphalangeal joint, septic tenosynovitis of the digital flexor tendon sheath or complicated interdigital necrosis. Sodium-Ceftiofur was applied in 34 dairy cattle in addition to surgical intervention. 14 cattle of the control group perceived only surgical intervention without additional antibiotic therapy. Application of the cephalosporin proved to be necessary, with the untreated animals exhibiting far more disturbance of the reconvalescence course in the postoperative phase. Treated animals had a decreasing duration of the postoperative stay at the clinic. Sodium-Ceftiofur was found to be an effective antibiotic in the therapy, an application over a five- to 10-day-period is recommended in complicated digital diseases. As a side effect five cows exhibited slight diarrhea, which disappeared without additional treatment.