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Gait analysis as subjective visual assessment forms the foundation of the veterinarian's lameness examination. Pelvic limb lameness is frequently seen in dogs and the stifle joint with its cruciate ligaments, is a main cause of lameness due to cruciate ligament deficiency. In this study, we developed an open-source three-dimensional musculoskeletal pelvic limb model of a 30 kg Labrador Retriever including cruciate ligaments, simulating the gait cycle of the walking movement with the open-source programs NMSBuilder (Institutio Ortopedico Rizzoli, Bologna, Italy) and OpenSim (National Center for Simulation in Rehabilitation Research (NCSRR), Stanford, CA, USA). The computer model generated muscle activations based on motion data. The computed activations were similar to experimental electromyogram data. Highest joint torque was in extension/flexion in the stifle joint at 54 Nm at 14% of the gait cycle with cruciate ligaments. Highest stifle joint reaction force was 408 N at 16% of the gait cycle and was reduced after adding cruciate ligaments. Especially the cranial cruciate ligament loads up to 102 N (34% body weight). Cranial cruciate ligament forces increase with stifle extension and decrease with stifle flexion. On the contrary, the caudal cruciate ligament loads up to 27 N (9% body weight) during the swing phase with a flexed stifle joint. The model was validated with electromyogram data. The model's predictions are plausible because joint torques and forces match the applied ground reaction forces in curve progression and in timing. This model forms a basis for further investigations into stifle surgery after cruciate ligament deficiency.

Objective The aim of this study was to measure surface pressures and force distribution on radius and ulna in healthy and dysplastic elbow joints in different positions using the finite element analysis (FEA). Study Design FEA was performed on computed tomographic data of healthy and fragmented coronoid process diseased elbow joints of Labrador Retrievers. It considered the articular cartilage, collateral ligaments, triceps and biceps muscle. The analysis of each joint was performed in four positions (standing position: 145 degrees and three positions of the stance phase of gait: beginning: 115 degrees, middle: 110 degrees, end: 145 degrees joint angle) in consideration of different ground reaction forces (standing: 88.3 N; stance phase of gait: 182.5 N). Results Mean values of total force of 317.5 N (standing), 590.7 N (beginning), 330.9 N (middle) and 730.9 N (end) were measured. The percentual force distribution resulted in a total of 49.56 ± 26.58% on the ulna with a very inhomogeneous distribution. A significant difference was detected between the positions ‘standing’ and ‘end’ (p = 0.0497) regardless of the joint condition. In some FEA results, visual assessment of the surface pressures indicated an increase in pressure in the region of the medial compartment without a uniform pattern. An increase in pressure resulted in an area increase in the pressure marks on the joint surface and measurable pressure was increased at a larger joint angle. Clinical Significance FEA can provide information about the transmission of force in the joint. Prior to the use of FEA in scientific clinical research for the simulation of force, further model improvements are necessary.

Background Different 3D-printed materials polyactic acid (PLA), polyamide (PA), polycarbonates (PC), acrylonitrile butadiene styrene (ABS) and GreenTEC Pro®I have been considered for surgical templates, but there is a sparity of data about how these materials are affected by steam sterilization. The aim of the current study was to test if and how these materials change morphologically when high temperature, pressure and humidity are applied during the steam sterilization process. The overall aim is to create patient-specific sawing templates for performing corrective osteotomies. After the designing process, test-specimens with five different materials: PLA, PC, ABS, PA and GreenTEC Pro® were 3D-printed in two filling grades (30 and 100%). The FDM method was used for printing. After 3D-printing, the test-specimens were steam sterilized with a standard program lasting 20 min, at a temperature of 121 °C and a pressure of 2–3 bar. In order to measure the deviation of the printed model, we measured the individual test-specimens before and after steam sterilization using a sliding gauge. Results PC, PA and ABS showed great morphological deviations from the template after 3D-printing and steam sterilization (> 1%) respectively. ABS proved unsuitable for steam sterilization. PLA and GreenTEC Pro® demonstrated fewer morphological deviations both before and after sterilization. Therefore, we decided to perform a second test just with PLA and Green-TEC Pro® to find out which material has the highest stability and is probably able to be used for clinical application. The smallest deviations were found with the GreenTEC Pro® solid body. After autoclaving, the specimens showed a deviation from the planned body and remained below the 1% limit. Conclusion Steam sterilization causes morphological deviations in 3D printed objects. GreenTEC Pro® seems to be a suitable material for clinical use, not only for intraoperative use, but also for precise modeling. Microbiological examination, as well as biomechanical tests, should be performed to further assess whether intraoperative use is possible.

The purpose of this study is to analyze the static magnetic field interactions for an ophthalmic-magnetic shunt implant with a ferromagnetic steel plate in a thin silicon layer. The plate is used for opening of a valve flap. Ten different sizes of this steel plate were investigated to characterize the relationship between the size of the metal and the magnetic forces of the static magnetic field of a 3.0 T MRI. The magnetic translation force F The translational force was found to be 10 times greater than the weight of a single plate. The plates were exposed to a high torque (grade 3 to 4). The seams and the tissue withstood more than a thousandfold of the determined translational force. No spontaneous, uncontrolled opening of the valve flap was visible in the MRI, as a result of which the intraocular pressure could decrease considerably. Due to the small size of the plates the translational force and the torque will be compensated by the silicon layer and also by the fixation in the eye. · Magnetic forces will be compensated by silicon layer and fixation in the eye.. · The magnetic-ophthalmological implant is not restricted in its function by the MRI magnetic field.. · The ophthalmic magnetic shunt implant can be considered conditionally MRI-safe..· Bodenstein A, Lüpke M, Seiler C et al. Evaluation of the static magnetic field interactions for a newly developed magnetic ophthalmic implant at 3 Tesla MRI. Fortschr Röntgenstr 2019; 191: 209 - 215.ZIEL: Das Ziel dieser Studie ist es, die Wirkungen eines statischen Magnetfeldes während einer MRT-Untersuchung auf ein magnetisch-ophthalmologisches Implantat in vitro zu bestimmen. Das Implantat besteht aus Silikon und einem eingebetteten Metallplättchen, das zur Öffnung einer Ventilklappe dient. Es wurden zehn unterschiedliche Größen des Metallplättchens untersucht, um die Abhängigkeit der magnetischen Kräfte von der Größe des Metallplättchens zu charakterisieren. Es wurden 10 Metallplättchen mit Größen zwischen 8 × 8 mm Die Translationskraft war in der Regel fast 10-mal so groß wie die Gewichtskraft F Durch die geringe Größe, die Silikonummantelung und die Fixation durch die Nähte können die Translationskraft und das Drehmoment kompensiert werden. · Die hohen magnetischen Kräfte werden von der Silikonummantelung und den Haltenähten kompensiert.. · Das magnetisch-ophthalmologische Implantat wird durch das MRT-Magnetfeld nicht in seiner Funktion eingeschränkt.. · Das Implantat kann als bedingt MRT-sicher angesehen werden..· Bodenstein A, Lüpke M, Seiler C et al. Evaluation of the static magnetic field interactions for a newly developed magnetic ophthalmic implant at 3 Tesla MRI. Fortschr Röntgenstr 2019; 191: 209 – 215.

The aim was to measure the effective dose of flat-detector CT (FDCT) whole-brain imaging, biphasic FDCT angiography (FDCT-A), and FDCT perfusion (FDCT-P) protocols and compare it to previously reported effective dose values of multidetector CT (MDCT) applications. We measured effective dose according to the IRCP 103 using an anthropomorphic phantom equipped with thermoluminescent dosimeters (TLDs). Placement was according to anatomical positions of each organ. In total, 60 TLDs (≥ 4 TLDs/organ) were placed into and onto the phantom to account for all relevant organs. Organs within the primary beam were covered with more TLDs. Additionally, we measured dose to the eye lens with two TLDs per eye. Protocols which we routinely use in clinical practice were measured on a biplane angiography system. The effective dose of the 20-s protocol/7-s protocol for whole-brain imaging was 2.6 mSv/2.4 mSv. The radiation dose to the eye lens was 24/23 mGy. For the biphasic high-/low-dose FDCT-A protocol, the effective dose was 8.9/2.8 mSv respectively. The eye lens dose was 60/14 mGy. The contribution of bolus tracking to the effective dose was 0.66 mSv (assuming average duration of 14 s). The multisweep FDCT-P protocol had an effective dose of 5.9 mSv and an eye lens dose of 46 mGy. Except for the high-dose biphasic FDCT-A protocol, FDCT applications used in neuroradiology have effective doses, which do not deviate more than 1 mSv from previously reported values for MDCT applications. However, the effective dose to the eye lens in commonly used stroke paradigms exceeds the recommended annual dose twofold. • Flat-detector computed tomography (FDCT) can be used for acute and periinterventional imaging of acute stroke patients and in neurointerventions. • Except for the high-dose FDCT angiography protocol, the effective doses do not deviate more than 1 mSv from previously reported values for multidetector CT applications. • Strategies to decrease the effective lens dose especially in younger patients should be evaluated in the future.

Objective of this phantom and cadaveric study was to compare the effective radiation dose (ED) and image quality (IQ) between C-arm computed tomography (CACT) using an ultra-high resolution 1×1 binning with a standard 16-slice CT (MDCT) arthrography of the wrist.ED was determined with thermoluminescence dosimetry using an anthropomorphic phantom and different patient positions. Imaging was conducted in 10 human cadaveric wrists after tri-compartmental injection of diluted iodinated contrast material and a wire phantom. IQ of MDCT was compared with CACT reconstructed with a soft (CACT1) and sharp (CACT2) kernel. High and low contrast resolution was determined. Three radiologists assessed IQ of wrist structures and occurrence of image artifacts using a 5-point Likert scale.ED of MDCT was comparable to standard CACT (4.3μSv/3.7μSv). High contrast resolution was best for CACT2, decreased to CACT1 and MDCT. Low contrast resolution increased between CACT2 and MDCT (P0.001). IQ was best for CACT2 (1.3±0.5), decreased to CACT1 (1.9±0.6) and MDCT (3.5±0.6). Non-compromising artifacts were only reported for CACT.The results of this phantom and cadaveric study indicate that ultra-high resolution C-Arm CT arthrography of the wrist bears the potential to outperform MDCT arthrography in terms of image quality and workflow at the cost of mildly increasing image artifacts while radiation dose to the patient is comparably low for both, MDCT and C-Arm CT.

Background Nephropathies are among the most common diseases in dogs. Regular examination of the kidney function plays an important role for an adequate treatment scheme. The determination of the glomerular filtration rate (GFR) is seen as the gold standard in assessing the kidney status. Most of the tests have the disadvantage that only the complete glomerular filtration rate of both kidneys can be assessed and not the single kidney glomerular filtration rate. Imaging examination techniques like dynamic contrast-enhanced magnetic resonance imaging have the potential to evaluate the single kidney GFR. There are studies in human medicine describing the determination of the single kidney GFR using this technique. To our knowledge there are no such studies for dogs. Results An exponential fit was found to describe the functional interrelation between signal intensity and contrast medium concentrations. The changes of contrast medium concentrations during the contrast medium bolus propagation were calculated. The extreme values of contrast medium concentrations in the kidneys were reached at nearly the same time in every individual dog (1st maximum aorta 8.5 s, 1st maximum in both kidneys after about 14.5 s; maximum concentration values varied between 17 and 125 µmol/mL in the aorta and between 4 and 15 µmol/mL in the kidneys). The glomerular filtration rate was calculated from the concentration changes of the contrast medium using a modified Rutland-Patlak plot technique. The GFR was 12.7 ± 2.9 mL/min m2 BS for the left kidney and 12.0 ± 2.2 mL/min/m2 BS for the right kidney. The mean values of the coefficient of determination of the regression lines were averagely 0.91 ± 0.08. Conclusions The propagation of contrast medium bolus could be depicted well. The contrast medium proceeded in a similar manner for every individual dog. Additionally, the evaluation of the single kidney function of the individual dogs is possible with this method. A standardized examination procedure would be recommended in order to minimize influencing parameters. Electronic supplementary material The online version of this article (10.1186/s13028-018-0423-3) contains supplementary material, which is available to authorized users.

Testicular biopsy is still uncommonly used in equine andrological diagnostics although several studies supported that it is a relatively safe procedure. So far, no data exist regarding repeated testicular biopsies in stallions. In the present study, repeated testicular biopsy samples were obtained from four stallions at 4-week intervals alternatingly from both testes over the period of 1 year. The objectives were to assess (1) effects of repeated testicular biopsies by clinical, morphologic, histologic, ultrasonographic, and infrared thermographic examinations and (2) the utility of the biopsy samples for diagnostic purposes, namely hematoxylin–eosin staining, immunohistochemistry, Western blot analysis, and polymerase chain reaction. No significant side effects could be determined on clinical healthiness, testis size, libido, testicular blood flow, testicular histology, and scrotal surface temperature. The biopsy samples provided sufficient tissue for assessing spermatogenesis, detecting and localizing proteins (immunohistochemistry), and for protein/messenger RNA extraction for Western blot analyses and polymerase chain reaction. The authors conclude that taking even repeated testicular biopsies is a practicable and safe technique for equine practice having only minimal side effects. The biopsy specimens are suitable for various diagnostic cell and molecular biology applications for identifying testicular causes of male equine infertility. Prospectively, also therapeutic applications might be possible to extend the prospects of already established assisted reproductive techniques (e.g., testicular sperm extraction followed by intracytoplasmic sperm injection) in stallions suffering from obstructive azoospermia or oligospermia. Repeated testicular biopsies might also provide benefits for scientific work, for example, to monitor effects of pharmaceuticals or seasonal variations on testis function and spermatogenesis in the same animal.

Background Technical failures and incorrect usage of digital X-ray systems may lead to a decreasing image quality, artefacts and a higher dose exposure of staff and patients. Although there are no regulations regarding constancy testing in veterinary radiology all operators are required to avoid unnecessary exposure. The aim of this study was to develop a reasonably inexpensive zoomorphic 3D-printed test specimen for constancy testing that allows the detection of changing image quality by visual analysis. Primarily, a calibration curve of the attenuation factor of the 3D-printing material (ZP150) was determined. MATLAB converted every pixel value of a thorax X-ray image of a Beagle dog into an equivalent thickness of printing material. The thickness distribution was printed using a 3D-printer. This printed test specimen was additionally provided with five thin aluminium discs to simulate lung nodules. To evaluate the usability for constancy testing 12 X-ray images of the test specimen were made. Two images (reference and control) were taken with the minimum dose in order to obtain images suitable for diagnosis purposes. Eight images were taken with a dose differing 30–140% from the reference dose by varying current–time product (mAs) or tube voltage (kVp). Two images were taken with the same parameters as the reference image but edited with different image processing. Six veterinarians (general practitioners) evaluated ten chosen structures in the X-ray images in a Visual Grading Analysis and scored the image quality of these structures for every image in comparison to the reference image. A Visual Grading Analysis Score was calculated and statistically analysed. Results A higher current–time product led to a negligibly better evaluation of the X-ray image. The lower the current–time product the worse the X-ray images were scored. Likewise, both increasing and decreasing of the tube voltage led to lower scores. Conclusions A zoomorphic test specimen can be used for constancy testing of digital X-ray systems in veterinary medicine. Especially a lower dose can be recognised due to deviation in the image quality when compared to the reference image. The 3D-printed test specimen is less expensive than test equipment used in human medicine.

Metallic biomaterials are widely used in maxillofacial surgery. While titanium is presumed to be the gold standard, magnesium-based implants are a current topic of interest and investigation due to their biocompatible, osteoconductive and degradable properties. This study investigates the effects of poly-ε-caprolactone-coated and previtalised magnesium implants on osteointegration within murine calvarial bone defects: After setting a 3 mm × 3 mm defect into the calvaria of 40 BALB/c mice the animals were treated with poly-ε-caprolactone-coated porous magnesium implants (without previtalisation or previtalised with either osteoblasts or adipose derived mesenchymal stem cells), porous Ti6Al4V implants or without any implant. To evaluate bone formation and implant degradation, micro-computertomographic scans were performed at day 0, 28, 56 and 84 after surgery. Additionally, histological thin sections were prepared and evaluated histomorphometrically. The outcomes revealed no significant differences within the differently treated groups regarding bone formation and the amount of osteoid. While the implant degradation resulted in implant shifting, both implant geometry and previtalisation appeared to have positive effects on vascularisation. Although adjustments in degradation behaviour and implant fixation are indicated, this study still considers magnesium as a promising alternative to titanium-based implants in maxillofacial surgery in future.

BACKGROUND Equine incisors are often reduced in height during corrective dental procedures. Increased knowledge of subocclusal dentine thickness and pulp morphology may help prevent iatrogenic pulpar exposure. Although such data exist for equine cheek teeth, there are currently no reliable data for incisors. OBJECTIVES To measure the distances between pulp cavities and the occlusal as well as the labial surfaces of equine incisors and to test if these distances change with age. Furthermore, pulp morphology with regard to number and orientation of pulp horns was investigated. STUDY DESIGN Observational study using cadaver material and high-resolution computed tomography. METHODS Upper and lower incisor arcades were removed from heads of 13 horses and scanned with high-resolution computed tomography. 3D Models were reconstructed and configuration as well as number of the pulp horns was evaluated. Anatomical marker points were set to measure distances between the pulp horn tips and the labial and occlusal surfaces. RESULTS Subocclusal dentine thickness ranged between 1.5 and 11.7 mm in upper and 0.7 and 6.7 mm in lower incisors. It decreased with tooth age. Distance to labial aspect ranged between 3.5 and 9.0 mm in upper and 3.8 and 8.1 mm in lower incisors and increased with tooth age. MAIN LIMITATIONS Details of horse management, feeding and previous dental care were not available. Therefore, it remains unknown how these factors influenced the results. CONCLUSIONS Although mean subocclusal dentine thickness of greater than 4.1 mm was found, equine incisors occasionally have less than 1 mm of thickness with potential for iatrogenic pulpar exposure during incisor reduction. Therefore, great care should be exercised by any practitioner during incisor reduction.

Metallic biomaterials are widely used in maxillofacial surgery. While titanium is presumed to be the gold standard, magnesium-based implants are a current topic of interest and investigation due to their biocompatible, osteoconductive and degradable properties. This study investigates the effects of poly-ε-caprolactone-coated and previtalised magnesium implants on osteointegration within murine calvarial bone defects: After setting a 3 mm × 3 mm defect into the calvaria of 40 BALB/c mice the animals were treated with poly-ε-caprolactone-coated porous magnesium implants (without previtalisation or previtalised with either osteoblasts or adipose derived mesenchymal stem cells), porous Ti6Al4V implants or without any implant. To evaluate bone formation and implant degradation, micro-computertomographic scans were performed at day 0, 28, 56 and 84 after surgery. Additionally, histological thin sections were prepared and evaluated histomorphometrically. The outcomes revealed no significant differences within the differently treated groups regarding bone formation and the amount of osteoid. While the implant degradation resulted in implant shifting, both implant geometry and previtalisation appeared to have positive effects on vascularisation. Although adjustments in degradation behaviour and implant fixation are indicated, this study still considers magnesium as a promising alternative to titanium-based implants in maxillofacial surgery in future. © 2017 by the authors.

In equine dentistry, periodontal diseases are frequently found in aged horses. Excessive strains and stresses within the periodontal ligament (PDL) occurring during the masticatory cycle may be predisposing factors especially in old horses with short, worn teeth. The finite element (FE) analysis is a valuable tool to investigate such strains and stresses in biological materials but a precondition for a realistic and reliable FE analysis is accurate knowledge of material parameters. As no data exist concerning the PDL of equine incisor teeth, this study was undertaken to determine the equine specific, age related and load dependent Young’s modulus of equine incisors. To determine the biomechanical behaviour of the PDL, the incisor jaw-regions of horses of different ages were sectioned into 5 mm thick slice samples and the incisors experimentally intruded (i.e. axially displaced into the alveolus) while recording the load–displacement relationship. Based on high resolution micro-computer tomography (μCT)-datasets, reliable and detailed 3-dimensional models of the slice samples were constructed focusing on precisely modelling the anatomy of the PDL. FE calculations were then performed and set-actual comparisons of the FE results with the experimentally measured displacements enabled the Young’s modulus of the PDL to be determined. The results of this study reflect the typical non-linear behaviour of the collagen fibres of the PDL and present a high load dependency of the PDL’s Young’s modulus. Further investigations calculating the strains and stresses within the periodontal ligament, teeth and surrounding bone of the entire rostral aspect of the jaw are warranted.

Background Functional magnetic resonance imaging (fMRI) is an advanced and frequently used technique for studying brain functions in humans and increasingly so in animals. A key element of analyzing fMRI data is group analysis, for which valid spatial normalization is a prerequisite. In the current study we applied normalization and group analysis to a dataset from an auditory functional MRI experiment in anesthetized beagles. The stimulation paradigm used in the experiment was composed of simple Gaussian noise and regular interval sounds (RIS), which included a periodicity pitch as an additional sound feature. The results from the performed group analysis were compared with those from single animal analysis. In addition to this, the data were examined for brain regions showing an increased activation associated with the perception of pitch. Results With the group analysis, significant activations matching the position of the right superior olivary nucleus, lateral lemniscus and internal capsule were identified, which could not be detected in the single animal analysis. In addition, a large cluster of activated voxels in the auditory cortex was found. The contrast of the RIS condition (including pitch) with Gaussian noise (no pitch) showed a significant effect in a region matching the location of the left medial geniculate nucleus. Conclusion By using group analysis additional activated areas along the canine auditory pathways could be identified in comparison to single animal analysis. It was possible to demonstrate a pitch-specific effect, indicating that group analysis is a suitable method for improving the results of auditory fMRI studies in dogs and extending our knowledge of canine neuroanatomy.

In a previous study we could demonstrate that in terms of the required forces alternate traction is preferable to simultaneous traction for the obstetrical delivery of calves. The aims of this study were to examine the required energies for delivery of calves and to compare the effects of the factors of calf and traction method on the forces and energies required for the delivery. In a biomechanical in vitro model 12 stillborn Holstein-Friesian calves were pulled through the pelvic specimen of a cow at a controlled speed using two electric motors. Traction was applied simultaneously (ST) to both legs or alternately (AT) to one leg at a time to advance it 10 cm (AT 10) or 5 cm (AT5). Energies on each limb were measured digitally using load cells. The lowest energy for the entrance of the elbows in the pelvis was necessary using AT10 (19.9 ± 7.2 kJ, P < 0.05). In contrast, for the entrance of the chest, AT10 (104.9 ± 24.7 kJ) demanded 9% (P < 0.01) and 16% (P < 0.001) more energy than AT5 (96.7 ± 21.0 kJ) and ST (90.5 ± 24.9 kJ), respectively. Simultaneous traction tended to be better than AT5 (P = 0.09). Variance component estimates revealed that the factor calf contributed the main effect to the emerging forces and required energy. The traction method was responsible for up to 13% of the variance in most of the cases, but it accounted for 42% of the variance regarding the forces on the lower limb as the chest entered the pelvis. Based on these findings, the decision of the clinician whether or not to perform a manual traction should depend mainly on the calf. However, when such a decision has been made, alternate limb traction, 10 cm at a time, should be used until both elbows have entered the pelvis and a simultaneous traction should then be applied to complete extraction of the chest.

Energy expenditure depends on resource availability (e.g. food, body reserves). Reproduction is a major energetic challenge for mammals living under highly variable seasonal conditions. Lactation represents the most energy demanding time in a female's annual cycle. To understand how important adaptations facilitating lactation are, we studied its energetic costs. Two ruminant species of similar size (about 25 kg body mass) were used in an investigation to learn more about their adaptations to seasonality: The European roe deer (Capreolus capreolus Linnaeus, 1758) and the European mouflon (Ovis orientalis musimon Schreber, 1782). Energy investment into lactation was estimated using stable isotope techniques with two different approaches. The D2O dilution technique for estimating milk intake described for sheep lambs by Coward et al. (1982) and the doubly labelled water method for measuring energy expenditure (Speakman 1997). Milk intake was estimated by the D2O dilution technique in 2-week-old roe deer fawns and mouflon lambs. Estimated milk intake rates were then transferred into the respective energetic investment into lactation. It was calculated as well from energy expenditure data in growing fawns during their first two weeks post partum using results of the doubly labelled water technique. Results for roe deer showed an energy investment into lactation of 5.6 MJ/d metabolizable energy (ME) per fawn. In mouflon this value was approximately 5.7 MJ/d per lamb. Twins are extremely rare in mouflon, they routinely get only one offspring per year. Keeping in mind that roe deer often give birth to twins, or sometimes even triplets we measured more than twice the energy investment into lactation than predicted from theoretical calculations (Lechner-Doll et al. 2000).

LiF:Mg,Cu,P is a very sensitive thermoluminescence material that can be used for personal dosimetry in radiology. But if this material is heated too much during annealing or reading it quickly loses its sensitivity. This study shows that an annealing oven in wide use can cause thermal damage to the dosemeters owing to inhomogeneous temperature distribution in the annealing tray. At annealing temperatures>240 degrees C, differences of only 1 degrees C lead to significant losses of sensitivity. Therefore, it is necessary to measure the distribution of temperature in the annealing tray for correct placement of the dosemeters in the tray.

So far no standard procedure exists to obtain water of meat for isotopic 18 O/ 16 O-water analysis. Fast extraction via heating the tissues is possible when considering certain boundary conditions. A specially designed vessel was tested with water and was then used for meat juice extraction. The reproducibility ( σ ) of δ 18 O-values was 0.12‰. Meat samples of six different species were analysed. Water of pork samples was extracted after open storage. Here, decreases in meat weight correspond to decreases in extract yield and to an increase in the 18 O/ 16 O-ratio. The mean water contents in extracts was almost constant [93.2 ± 0.05 wt% ( p > 0.05)]. The technique offers an opportunity to develop an automatic, mobile extraction device and to obtain extracts with no further influences on their quality. This method could also be useful for the determination of meat quality attributes as cooking loss or drip without evaporative losses.

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region.

Background Functional magnetic resonance imaging (fMRI) is a technique able to localize neural activity in the brain by detecting associated changes in blood flow. It is an essential tool for studying human functional neuroanatomy including the auditory system. There are only a few studies, however, using fMRI to study canine brain functions. In the current study ten anesthetized dogs were scanned during auditory stimulation. Two functional sequences, each in combination with a suitable stimulation paradigm, were used in each subject. Sequence 1 provided periods of silence during which acoustic stimuli could be presented unmasked by scanner noise (sparse temporal sampling) whereas in sequence 2 the scanner noise was present throughout the entire session (continuous imaging). The results obtained with the two different functional sequences were compared. Results This study shows that with the proper experimental setup it is possible to detect neural activity in the auditory system of dogs. In contrast to human fMRI studies the strongest activity was found in the subcortical parts of the auditory pathways. Especially sequence 1 showed a high reliability in detecting activated voxels in brain regions associated with the auditory system. Conclusion These results indicate that fMRI is applicable for studying the canine auditory system and could become an additional method for the clinical evaluation of the auditory function of dogs. Additionally, fMRI is an interesting technique for future studies concerned with canine functional neuroanatomy.

This study investigated the hypothetical contribution of biomechanical loading to the onset of equine odontoclastic tooth resorption and hypercementosis (EOTRH) and to elucidate the physiological age-related positional changes of the equine incisors. Based on high resolution micro-computed tomography (μCT) datasets, 3-dimensional models of entire incisor arcades and the canine teeth were constructed representing a young and an old incisor dentition. Special attention was paid to constructing an anatomically correct model of the periodontal ligament (PDL). Using previously determined Young’s moduli for the equine incisor PDL, finite element (FE) analysis was performed. Resulting strains, stresses and strain energy densities (SEDs), as well as the resulting regions of tension and compression within the PDL and the surrounding bone were investigated during occlusion. The results showed a distinct distribution pattern of high stresses and corresponding SEDs in the PDL and bone. Due to the tooth movement, peaks of SEDs were obtained in the PDL as well as in the bone on the labial and palatal/lingual sides of the alveolar crest. At the root, highest SEDs were detected in the PDL on the palatal/lingual side slightly occlusal of the root tip. This distribution pattern of high SEDs within the PDL coincides with the position of initial resorptive lesions in EOTRH affected teeth. The position of high SEDs in the bone can explain the typical age-related alteration of shape and angulation of equine incisors.

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region.

Background In equine dentistry periodontal diseases, especially periapical inflammation, are frequently occurring problems. Anachoresis is believed to be the most common cause for the development of such disorders. Nevertheless, there is still no substantiated explanation why settlement of pathogen microorganisms occurs in equine periodontal tissues. It is expected that excessive strains and stresses occurring in the periodontal ligament (PDL) during the horse’s chewing cycle might be a predisposing factor. In this study this assumption was examined by finite element (FE) analyses on virtual 3-D models of equine maxillary and mandibular cheek teeth, established on the basis of μCT datasets. Calculations were conducted both under conditions of closing and power stroke. Results Results showed a uniform distribution of low stresses and strain energy density (SED) during closing stroke, whereas during power stroke an occurrence of high stresses and SED could be observed in the PDL near the alveolar crest and in periapical regions. Conclusion The concentration of forces during power stroke in these specific areas of the PDL may cause local tissue necrosis and inflammation and thus establish a suitable environment for the settlement of microorganisms.

Periodontal diseases occur frequently in equine dentistry and excessive strain in biological tissues is assumed to be a predisposing factor in their development. Finite element (FE) analysis enables strains and stresses occurring in the periodontium to be calculated and is a useful tool for testing this hypothesis. The current study aimed to establish reliable 3-D models from equine maxillary and mandibular cheek teeth for use in FE simulations, with particular attention to the detailed construction of the periodontal ligament (PDL). Age-related morphological aspects of the teeth and the periodontium were also considered by constructing different models for three defined age groups. Finally, the biomechanical behaviour of the equine PDL was examined during experimental tooth intrusion (i.e. axial displacement of the tooth into its alveolar socket). The results showed an increase in intrusion with increasing age due to age-related changes in the periodontal elastic properties. The general stress level in PDL and surrounding bone also increased with age. Reliable FE models were established to calculate aetiologically relevant biomechanical effects occurring in the equine periodontium.

The aim of this study was to develop an examination protocol for magnetic resonance imaging, in order to display diagnostically important information of the canine middle and inner ear. To ensure that this protocol could also be used as a basis for determining pathological changes, the anatomical structures of the ear were presented in detail. To minimise stress through anaesthesia in live animals, preliminary examinations were carried out on four dog cadavers. During these initial examinations, three-dimensional (3D) sequences proved to be superior to two-dimensional ones. Therefore, only 3D sequences were applied for the main examinations performed on six clinically healthy Beagles. The anonymised MR images were rated by three experienced reviewers using a five-point scale. The most valuable sequence was a T2-weighted CISS sequence (TR = 16.7 ms, TE = 8.08 ms). This sequence proved to be most suitable for illustrating the inner ear structures and enabled good tissue contrasts. The sequence ranked second best was also a T2-weighted DESS sequence (TR = 19 ms, TE = 6 ms), allowing the imaging of the tympanic cavity and enabling 3D reconstruction due to its isotropic voxels. Due to low contrast and strong noise, the other sequences (TSE, FISP, MP RAGE) were not suitable for anatomical illustration of the middle and inner ear.

Changes in the rate of dentate granule cell neurogenesis and in the fate of newborn granule cells have been implicated in the development and progression of epilepsies. Strategies to normalize neurogenesis in chronic epilepsy models are thought to increase our understanding of the functional consequences of aberrant neurogenesis in the epileptic brain. Therefore, we modulated neurogenesis in an amygdala kindling paradigm in rats by targeted irradiation of the hippocampus using a medical linear accelerator device. Selective irradiation normalized the hippocampal cell proliferation rate in kindled animals. Both, in kindled and nonkindled rats the number of BrdU/NeuN-labeled newborn neurons was reduced in response to irradiation. Whereas kindling resulted in a pronounced increase in the number of neuroblasts identified based on doublecortin-labeling, irradiation prevented the expansion of the neuroblast population. Moreover, irradiation counteracted the kindling-associated increase in hilar basal dendrites, and kept the fraction of cells with basal dendrites at control levels. Despite the efficacious modulation of neurogenesis, irradiation did not affect the rate of kindling progression. Both, the number of stimulations as well as the cumulative afterdischarge duration to reach respective seizure stages were comparable in animals with and without irradiation. In addition, pre- and postkindling thresholds as well as seizure parameters recorded at threshold stimulation remained unaffected by irradiation. In conclusion, the fact that the efficacious modulation of neurogenesis by irradiation did not exert any effects on kindling acquisition and kindled seizures suggests that newborn neurons do not critically contribute to the hyperexcitable state in the chronic epilepsy model used.

Whether extraction of a calf in longitudinal anterior presentation should be carried out by simultaneous or alternate traction on the forelimbs remains controversial. Because most recommendations are based on empirical observations rather than on scientific studies, the aim of this study was to develop an in vitro model to objectively compare the forces occurring during alternate and simultaneous traction. In a biomechanical in vitro model, 12 dead Holstein-Friesian (Bos taurus) calves were pulled through the prepared pelvic specimen of a cow at a controlled speed using two electric motors. Traction was applied simultaneously (ST) to both legs or alternately (AT) to one leg at a time to advance the calf 5 cm (AT 5) or 10 cm (AT 10). Forces on each limb were measured digitally using load cells. In all cases, two peaks of maximum force occurred during the extraction of the cranial part of the body. The first peak was observed when the elbows were pulled into the pelvis, and the second peak occurred when the chest emerged from the pelvis. Up to and including entry of the elbows into the pelvis, the maximum force on a single limb (341+/-106 N) was lowest (P0.01) using AT10. The maximum traction forces acting on a single limb using AT5 (411+/-86 N) and ST (431+/-127 N) did not differ (P0.05). During extraction of the thorax, the maximum force acting on a single limb was lower (P0.0001) using ST (352+/-98 N) compared with AT5 (432+/-79 N) and AT10 (547+/-115 N). Based on these findings, alternate-limb traction, 10 cm at a time, should be used until both elbows have entered the pelvis. Simultaneous traction should then be applied to both forelimbs to complete extraction of the chest.

The aim of this study was to optimize magnetic resonance imaging (MRI) sequences, which are already used for examinations of dog noses, to show more detail of the fine structures of the nose. Examinations were first carried out on phantoms. The resulting improved sequence parameters were further optimized on five clinically healthy animals. Images were made using nine optimized sequences on another five clinically healthy dogs, and the image quality was evaluated by three reviewers. Detail recognition and contour sharpness of the conchae and turbinates in the peripheral and central regions were evaluated as were image noise, contrast, subjective image quality, and diagnostic value. The best evaluation was given to a spin echo sequence. Second place went to a turbo spin echo sequence. Both sequences were proton density-weighted. The gradient echo sequences received the poorest evaluation and proved to be unsuitable for the anatomic portrayal of the nose. The TSE-sequence is more suitable to the clinical routine because of the significant shorter measure time compared to the SE-sequence. In case of suspected pathologic changes, a T2-weighted image sequence must also always be acquired, despite it being inappropriate to illustrate anatomic details.

The knowledge of the radiation exposure of the staff involved in X-ray examinations is one precondition for an optimisation of radiation protection. Hence the radiation exposure of the staff during X-ray examinations of dogs and cats was investigated in the Clinic for Small Animals. The study includes at least ten measurements for each of thirteen X-ray examinations of a dog and four of a cat. The equivalent doses of eye lens, thyroid, chest, hands, gonads, and lower leg were measured using TLD (LiF:Mg,Cu,P). The maximum values of 44.3 and 48.3 microSv were measured on the eye lens and the thyroid, respectively. The median and mean values of the equivalent doses on the seven measuring positions with the exception of eye lens (6.0 microSv) are lower than 5 microSv per radiograph. More than 95% of the equivalent doses on chest, hands, gonads, and lower leg are smaller than 2 microSv. Particularly eye lenses and thyroid are exposed to measurable doses. Altogether the radiation exposure of the staff is relatively low. Hence a manual fixation of animals is justifiable if the fundamental rules of radiation protection are observed.

In Germany pet owners are present during X-ray examinations of dogs and cats. Due to a change in the German X-ray Ordinance and the directive "Radiation Protection in Veterinary Medicine" it is necessary to determine the body dose of the pet owners. This study in the Clinic for Small Animals includes at least ten measurements for each of thirteen X-ray examinations of a dog and four of a cat. The equivalent doses of eye lens, thyroid, chest, hands, gonads, and lower leg were measured using TLD (LiF:Mg,Cu,P). The maximum value of 52 microSv was measured on the right hand. The 99 % -quantiles amount to 13 microSv for eye lens, 9 microSv for thyroid, 2.3 microSv for chest (under lead apron), 14 microSv for both hands, 2.1 microSv for gonads (under lead apron), and 2.0 microSv for lower leg. In every case the median and mean values at the seven measuring positions are lower than 2.5 microSv per radiograph. In view of the constant measured equivalent doses under the lead apron of less than 5 microSv for the trunk and gonads per X-ray examination the measurement of the personal dose of the pet owner during every X-ray examination of small animals is not justified. Alternatively, with reference to up-to-date measurements and the presented paper a certificate of exemption from the dose determination for pet owners could be applied for from the local authority.

The present study investigated the microbial degradation of the plant flavonol quercetin and its naturally occurring glycosides isoquercitrin and rutin in the porcine hindgut. The experiments were carried out with the semicontinuous colon-simulation technique. The fluid and particle phase of pig hindgut contents from freshly slaughtered animals were used for the in vitro incubations. Following a five-day equilibration period, quercetin, isoquercitrin or rutin were administered to fermentation vessels and their turnover rate was determined. None of the flavonols affected parameters of microbial fermentation like pH, redox potential or VFA production. The turnover rate for isoquercitrin was seven times higher than the turnover for the fermentation fluid. The turnover rates for quercetin and rutin were four and twofold higher than fluid turnover, respectively. After administration of isoquercitrin or rutin, their aglycone quercetin was detected as an intermediary metabolite. Under sterile conditions using autoclaved incubation fluids and hindgut contents, turnover rates for quercetin and rutin were still higher than the fluid turnover in the fermentation vessels. This indicates a certain chemical instability of the flavonols and/or adsorption to ingesta particles. Thus, flavonols are subjected to microbial metabolism in the porcine hindgut. The glycosidic structure strongly influences the rate of metabolism.

With respect to the question of whether the 18O/16O-ratio of meat water could be used for meat origin analysis, factors influencing its delta18O-value have been examined. The 18O/16O-ratio of meat water differs geographically, similar to known differences in precipitation and ground water. In Great Britain higher enrichments in 18O were found in southern samples and in Germany in northern samples. However, it was not possible to distinguish between British and German beef: their 18O/16O-ratios overlapped. British bovine samples the variation range of delta18O-values was 2.8 per thousand; in porcine samples it was 2.0 per thousand. British meat liquids from beef were enriched in 18O by 1.3 +/- 0.3 per thousand compared with pork. In porcine samples of litter mates with identical breeding and age at slaughter, the range in the delta18O-values among individuals was 2.4 per thousand. Experiments revealed significant influences of the meat's storage and handling conditions on the 18O/16O-ratio. After 10 h at 21.5 or 18.5 degrees C the delta18O-value increased by 0.4 or 0.3 per thousand per h, respectively, in samples (50 g) of chopped meat. The observed magnitude of changes might compensate for the geographical and seasonal differences. A precise origin assignment of the affected specimen on the base of delta18O-values of meat water is hence bound to be impossible.

Background Sinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads. Results Three-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P