3D approaches to culturing bovine skin: explant culture versus organotypic skin model.

INTRODUCTION: Digital Dermatitis (DD) in cattle appears with high prevalence, nevertheless the knowledge on its pathogenesis is still limited. In this context, in vitro skin models represent a valuable tool to facilitate the study of DD. METHODS: Two in vitro skin models were established using bovine distal limb skin: a skin explant model and an organotypic skin model. For the skin explant model, skin samples were cultured with an air-liquid interface for up to 7 days. Besides routine histopathological examination, read-out parameters were Ki-67 and cleaved Caspase-3 stainings. For the organotypic model, primary keratinocytes were layered on top of a dermal equivalent containing mainly mitotically inactive fibroblasts and maintained for up to 21 days. At regular intervals (day 7, 14 and 21), cultured skin samples were taken for (immuno)histological analysis. RESULTS: Both cultures could be maintained for the entire duration of the intended culture period. In the histopathological assessment, explant skin cultures showed ballooning degeneration of keratinocytes and segmental necrosis starting at day 5 of culturing. Initially basal keratinocytes in the organotypic model differentiated as demonstrated by positive Keratin 14, Desmoglein-1, Loricrin and Involucrin immunofluorescent stainings. Ki-67 was observed occasionally and suprabasally still after 21 days of culture. CONCLUSION: Both in vitro models proved dependable and constitute a viable option for replacing experiments on live animals, each with its own benefits. Whereas skin explants include all cell types available in vivo and can therefore reflect realistic cell-cell-interactions and signaling pathways, the organotypic model offers a higher standardization and reproducibility. Depending on the focus of future studies, both models can be used for specific experimental purposes of bovine dermatological research in general or specialized questions concerning (infectious) claw diseases as e.g. DD.

Gait Analysis in Walking and Trotting Dairy Cows on Different Flooring Types with Novel Mobile Pressure Sensors and Inertial Sensors.

Mechanical overburdening is a major risk factor that provokes non-infectious claw diseases. Moreover, lameness-causing lesions often remain undetected and untreated. Therefore, prevention of claw tissue overburdening is of interest, especially by analyzing harmful effects within dairy cows' housing environment. However, objective "on-cow" methods for bovine gait analysis are underdeveloped. The purpose of the study was to apply an innovative mobile pressure sensor system attached at the claws to perform pedobarometric gait analysis. A further goal was the supplementation with accelerative data, generated simultaneously by use of two inertial measurement units (IMUs), attached at metatarsal level. IMU data were analyzed with an automatic step detection algorithm. Gait analysis was performed in ten dairy cows, walking and trotting on concrete flooring and rubber mats. In addition to the basic applicability of the sensor systems and with the aid of the automatic step detection algorithm for gait analysis in cows, we were able to determine the impact of the gait and flooring type on kinematic and kinetic parameters. For pressure sensor output, concrete was associated with significantly (p < 0.001) higher maximum and average pressure values and a significantly smaller contact area, compared to rubber mats. In contrast to walking, trotting led to a significantly higher force, especially under the medial claw. Further, IMU-derived parameters were significantly influenced by the gait. The described sensor systems are useful tools for detailed gait analysis in dairy cows. They allow the investigation of factors which may affect claw health negatively.

A therian mammal with sprawling kinematics? Gait and 3D forelimb X-ray motion analysis in tamanduas.

Therian mammals are known to move their forelimbs in a parasagittal plane, retracting the mobilised scapula during stance phase. Non-cursorial therian mammals often abduct the elbow out of the shoulder-hip parasagittal plane. This is especially prominent in Tamandua (Xenarthra), which suggests they employ aspects of sprawling (e.g. lizard-like) locomotion. Here, we tested whether tamanduas use sprawling forelimb kinematics, i.e. a largely immobile scapula with pronounced lateral spine bending and long-axis rotation of the humerus. We analysed high-speed videos and used X-ray motion analysis of tamanduas walking and balancing on branches of varying inclinations and provide a quantitative characterization of gaits and forelimb kinematics. Tamanduas displayed lateral sequence/lateral couplets on flat ground and horizontal branches, but increased diagonality on steeper inclines and declines, resulting in lateral sequence/diagonal couplets gaits. This result provides further evidence for high diagonality in arboreal species, probably maximising stability in arboreal environments. Further, the results reveal a mosaic of sprawling and parasagittal kinematic characteristics. The abducted elbow results from a constantly internally rotated scapula about its long axis and a retracted humerus. Scapula retraction contributes considerably to stride length. However, lateral rotation in the pectoral region of the spine (range: 21 deg) is higher than reported for other therian mammals. Instead, it is similar to that of skinks and alligators, indicating an aspect generally associated with sprawling locomotion is characteristic for forelimb kinematics of tamanduas. Our study contributes to a growing body of evidence of highly variable non-cursorial therian mammal locomotor kinematics.

Suspensory ligament or interosseous muscle? Histology of the interosseous muscle of South American Camelids.

The interosseous muscles (IOM) have evolved to largely collagenized structures in many large grazers, including South American Camelids (SACs). SACs include lama (Lama glama), alpaca (Vicugna pacos), guanaco (Lama guanicoe) and vicuna (Vicugna vicugna). This study reports on a comparative histomorphological evaluation of the IOM in these four species. First, a descriptive qualitative analysis of the tissue composition within the physiological IOM clearly demonstrates that the IOM of all SAC species is predominantly tendinous. However, we can always find a small amount of striated muscle fibres supporting the claim that the term "interosseous muscle" should be preferred over the denomination "suspensory ligament". Second, we quantify the ratio of muscle tissue (MTr) occupying the cross-sectional area (CSA) of 80 limbs at three levels and examine it in relation to limb, sample localization and species. Values for MTr are highest at the middle level, ranging from 0.4% to 15.2% with a mean of 3.4% ± 3.2%. We also detect notable amounts of muscle tissue at the distal sample level in the area of the branches of the IOM. Of all SACs, alpacas present the highest MTr. Lamas have a significantly larger MTr than guanacos. These results suggest the influence of domestication and/or physical activity on the muscle tissue content of the IOM of SACs. Amounts and distribution of muscle, adipose and lose connective tissue vary greatly for each sample localization and within individuals of one species. This may complicate the interpretation of MRI images of SACs' IOM for diagnostic purposes.

[Chronic bee paralysis virus - quo vadis? Incidence in Bavaria and consideration of therapeutic measures]. / Chronische-Bienenparalyse-Virus ­ quo vadis? Auftreten in Bayern und Betrachtung von Therapiemaßnahmen.

OBJECTIVE: Chronic bee paralysis virus (CBPV), a so far unclassified RNA virus that may cause neurological signs and hairless black syndrome in honey bees, has become increasingly prevalent in various European countries in recent years. The disease occasionally leads to immense losses of worker bees and a significant drop in performance, especially in strong colonies. The aim of this retrospective study was to analyse the spread of CBPV in Bavaria from 2018 to 2020 as well as to evaluate therapeutic measures. MATERIAL AND METHODS: In part 1 of the study, analysis results of the Tiergesundheitsdienst Bayern e. V. (Bavarian Animal Health Service) from 302 bee colonies were examined with regard to virus diagnostics and clinical signs with a focus on CBPV. In part 2, data collected with the help of a questionnaire regarding 105 CBPV-positive and symptomatic colonies were evaluated. RESULTS: In part 1, a significant (p = 0.004) increase in CBPV-positive samples from 2018 to 2020 was detected within Bavaria. In addition, the number of cases with clinical signs also increased during the last 2 years. Part 2 of the study showed a clustering of reports of initial onset of CBPV symptoms during springtime. The colonies mostly with a combination of symptoms recovered from the disease in 57 % of the cases. Therapeutic intervention was one decisive factor. A large number of different combinations of measures led to survival, and a lack of intervention mostly resulted in the death of the colony. In 62 % of the diseased and isolated colonies, isolation prevented further spread in the apiary. CONCLUSION UND CLINICAL RELEVANCE: Based on the results, CBPV occurred more frequently in connection with clinical signs in Bavaria in recent years. Due to the large number of applied combinations of measures, no evidence-based therapy recommendation may be derived based on the current evaluations. However, it has been shown that any therapeutic intervention is superior to withholding treatment. For precise therapy recommendations, trials with treatment under standard conditions are necessary.

Biplanar High-Speed Fluoroscopy of Pony Superficial Digital Flexor Tendon (SDFT)-An In Vivo Pilot Study.

The superficial digital flexor tendon (SDFT) is the most frequently injured structure of the musculoskeletal system in sport horses and a common cause for early retirement. This project's aim was to visualize and measure the strain of the sound, injured, and healing SDFTs in a pony during walk and trot. For this purpose, biplanar high-speed fluoroscopic kinematography (FluoKin), as a high precision X-ray movement analysis tool, was used for the first time in vivo with equine tendons. The strain in the metacarpal region of the sound SDFT was 2.86% during walk and 6.78% during trot. When injured, the strain increased to 3.38% during walk and decreased to 5.96% during trot. The baseline strain in the mid-metacarpal region was 3.13% during walk and 6.06% during trot and, when injured, decreased to 2.98% and increased to 7.61%, respectively. Following tendon injury, the mid-metacarpal region contributed less to the overall strain during walk but showed increased contribution during trot. Using this marker-based FluoKin technique, direct, high-precision, and long-term strain measurements in the same individual are possible. We conclude that FluoKin is a powerful tool for gaining deeper insight into equine tendon biomechanics.

Cyclic tensile tests of Shetland pony superficial digital flexor tendons (SDFTs) with an optimized cryo-clamp combined with biplanar high-speed fluoroscopy.

BACKGROUND: Long-term cyclic tensile testing with equine palmar/plantar tendons have not yet been performed due to problems in fixing equine tendons securely and loading them cyclically. It is well established that the biomechanical response of tendons varies during cyclic loading over time. The aim of this study was to develop a clamping device that enables repetitive cyclic tensile testing of equine superficial digital flexor tendon for at least 60 loading cycles and for 5 min. RESULTS: A novel cryo-clamp was developed and built. Healthy and collagenase-treated pony SDFTs were mounted in the custom-made cryo-clamp for the proximal tendon end and a special clamping device for the short pastern bone (os coronale). Simultaneously with tensile testing, we used a biplanar high-speed fluoroscopy system (FluoKin) to track tendon movement. The FluoKin system was additionally validated in precision measurements. During the cyclic tensile tests of the SDFTs, the average maximal force measured was 325 N and 953 N for a length variation of 2 and 4 % respectively. The resulting stress averaged 16 MPa and 48 MPa respectively, while the modulus of elasticity was 828 MPa and 1212 MPa respectively. Length variation of the metacarpal region was, on average, 4.87 % higher after incubation with collagenase. The precision of the FluoKin tracking was 0.0377 mm, defined as the standard deviation of pairwise intermarker distances embedded in rigid bodies. The systems accuracy was 0.0287 mm, which is the difference between the machined and mean measured distance. CONCLUSION: In this study, a good performing clamping technique for equine tendons under repetitive cyclic loading conditions is described. The presented cryo-clamps were tested up to 50 min duration and up to the machine maximal capacity of 10 kN. With the possibility of repetitive loading a stabilization of the time-force-curve and changes of hysteresis and creep became obvious after a dozen cycles, which underlines the necessity of repetitive cyclical testing. Furthermore, biplanar high-speed fluoroscopy seems an appropriate and highly precise measurement tool for analysis of tendon behaviour under repetitive load in equine SDFTs.

Selective intra-carotid blood cooling in acute ischemic stroke: A safety and feasibility study in an ovine stroke model.

Selective therapeutic hypothermia (TH) showed promising preclinical results as a neuroprotective strategy in acute ischemic stroke. We aimed to assess safety and feasibility of an intracarotid cooling catheter conceived for fast and selective brain cooling during endovascular thrombectomy in an ovine stroke model.Transient middle cerebral artery occlusion (MCAO, 3 h) was performed in 20 sheep. In the hypothermia group (n = 10), selective TH was initiated 20 minutes before recanalization, and was maintained for another 3 h. In the normothermia control group (n = 10), a standard 8 French catheter was used instead. Primary endpoints were intranasal cooling performance (feasibility) plus vessel patency assessed by digital subtraction angiography and carotid artery wall integrity (histopathology, both safety). Secondary endpoints were neurological outcome and infarct volumes.Computed tomography perfusion demonstrated MCA territory hypoperfusion during MCAO in both groups. Intranasal temperature decreased by 1.1 °C/3.1 °C after 10/60 minutes in the TH group and 0.3 °C/0.4 °C in the normothermia group (p < 0.001). Carotid artery and branching vessel patency as well as carotid wall integrity was indifferent between groups. Infarct volumes (p = 0.74) and neurological outcome (p = 0.82) were similar in both groups.Selective TH was feasible and safe. However, a larger number of subjects might be required to demonstrate efficacy.

Development of a constant pressure perfused ex vivo model of the equine larynx.

Distal axonopathy is seen in a broad range of species including equine patients. In horses, this degenerative disorder of the recurrent laryngeal nerve is described as recurrent laryngeal neuropathy (RLN). The dysfunctional innervation of the cricoarytenoideus dorsalis muscle (CAD) leads to a loss of performance in affected horses. In general, ex vivo models of the larynx are rare and for equine patients, just one short report is available. To allow for testing new therapy approaches in an isolated organ model, we examined equine larynges in a constant pressure perfused setup. In order to check the vitality and functionality of the isolated larynx, the vessels´ reaction to norepinephrine (NE) and sodium nitroprusside (NP) as vasoactive agents was tested. Additionally, the contractility of the CAD was checked via electrical stimulation. To determine the extent of hypoxic alterations, lactate dehydrogenase (LDH) and lactate were measured and an immunofluorescent analysis of hypoxia-inducible factor (HIF-1α), a key transcription factor in hypoxia, was performed. For this, a hypoxia-induced cell culture for HIF-1α was developed. The application of NE led to an expected vasoconstriction while NP caused the expected vasodilation. During a perfusion period of 352 ±20.78 min, LDH values were in the reference range and lactate values slightly exceeded the reference range at the end of the perfusion. HIF-1α nuclear translocation could reliably be detected in the hypoxia-induced cell cultures, but not in sections of the perfused CAD. With the approach presented here, a solid basis for perfusing equine larynges was established and may serve as a tool for further investigations of equine larynx disorders as well as a transferrable model for other species.

[Curative claw trimming for mechanical relief of sole ulcers - an ex-vivo study]. / Kurative Klauenpflege zur mechanischen Entlastung von Sohlengeschwüren ­ eine Ex-vivo-Studie.

OBJECTIVE: Overloading or excessive mechanical stress to the claws may damage the sensitive claw tissues and subsequently lead to sole ulcers. Corrective treatment can prevent complications of these sole ulcers. The aim of this study was to investigate the effects of a wedge-shaped relief incision from the bulb to the tip of the outer claw of the pelvic limb on the pressure distribution beneath the pertaining claw. Furthermore, it aimed to clarify whether a change in the pressure distribution would lead to dermal pressure relief in the area of a horn defect. MATERIAL AND METHODS: Nineteen isolated bovine limbs from an abattoir were gradually trimmed resulting in following stages. A: initial condition; B: functional claw trimming, steps 1-3; C: extension of the model and drill of a circular lesion at the Rusterholz site (outer claw ulcer simulation); D: wedge shaped, weight-relieving incision from the bulb halfway towards the sole tip; E: further extension of the wedge-shaped incision towards the sole tip. The limbs were loaded with 200 kg following each of the procedures. A pressure sensor system was used in order to analyze the pressure distribution beneath the claws. Furthermore, positioning of the claws on a glass plate allowed for an evaluation of corium resp. fat cushion protrusion through the artificial lesion. RESULTS: In the untrimmed claws, an average of 63 % of the total force applied rested on the outer claw area. This value decreased to 30 % following step E. Maximum pressure values shifted from the bulb area towards the sole tip with increasing degree of claw trimming. The relative loading area of the inner claw increased to up to 18.4 % following the procedures. The described incision technique (step E) resulted in a significant reduction of corium protrusion through the artificial horn defect in comparison to the claw situation in step C. CONCLUSION: The wedge-shaped, weight-relieving incision (step E) led to pressure reduction in the area of the outer claw and the bulb region in this ex-vivo-study. Therefore, this trimming method may serve to relieve pressure from the vulnerable Rusterholz site as well as providing means for reducing corium compression. CLINICAL RELEVANCE: The described trimming method facilitates pressure relief on the outer claw area in live animals. In this, it may exert a positive effect on disease progression in Rusterholz sole ulcers.

Comparative anatomic and morphometric examination of the interosseous muscle, sesamoid ligaments and flexor tendons of the fetlock in South American camelids.

This study presents a comparative morphological and morphometrical examination of the interosseous muscle (IOM), digital flexor tendons and associated structures of all four species of South American Camelids (SACs): Lama (Lama glama), alpaca (Vicugna pacos), guanaco (Lama guanicoe) and vicuna (Vicugna vicugna). Our findings show that the lamoid interosseous muscle and digital flexor tendons are very similar between species and differences, which have been reported previously, are possibly due to diverging examiner interpretation. Lumbricalis muscles were mostly found as single muscles in this study. The definition of the terminal and dorsal branches of the interosseous muscle is critically revised. The analysis of morphometric data indicates that the size of the individual has a substantial influence on the cross-sectional area (CSA) of the examined structures. Metacarpal/metatarsal bone width is a main predictor of CSA, while the factor species only shows significance in specific sample points. For lama and alpaca, no differences in CSA in relation to species as factor were found. The IOM shows the largest CSAs of the three examined structures in all species, which implies an important load-bearing function. Considerable individual variation remains unexplained by the mentioned factors. This lowers the prospect of CSA reaching diagnostic importance in SAC fetlock pathology.

Dacryops with extensive lacrimal and maxillary bone defects in four dogs.

OBJECTIVE: To describe and discuss ventromedial orbital lacrimal gland or duct cysts (dacryops) in dogs with extensive bone defects based on their symptoms, results of diagnostic imaging and histopathological examination, and therapy and discuss their potential origin based on the morphology. ANIMALS STUDIED: Four dogs of different breeds, age, and sex were presented with a unilateral round, slow growing, indolent, and non-tender process ventromedial to the nasal canthus of the eye. PROCEDURES: Transverse computed tomography showed a low-density, non-contrast-enhancing cystic process ventromedial to the globe with extensive defects in the lacrimal and maxillary bones in all cases. The cystic character of the structure was confirmed by the aspiration of the brownish fluid without cellular and microbiological contents. For treatment, the cystic fluid was aspirated, and the sclerosing agent polidocanol was injected in three cases. Cystorhinostomy (nasal marsupialisation) was performed in one case as the first choice and in another case following failure of sclerotherapy. Histopathological examination of the cyst walls was performed in two cases and confirmed the diagnosis of dacryops. RESULTS: Follow-up between 2 and 18 months showed no recurrence and very good to excellent cosmetic results. CONCLUSIONS: Aberrant lacrimal gland or duct tissue with secondary development of dacryops should be included in the differential diagnoses of ventromedial orbital cysts. Large cysts near the lacrimal drainage system with extensive bone defects in dogs should be treated by nasal marsupialization. Treatments such as evacuation of the cyst and inducing sclerosis (sclerotherapy) should be reserved for exceptional cases.

Veterinary Diagnostic Approach of Common Virus Diseases in Adult Honeybees.

Veterinarians are educated in prevention, diagnosis and treatment of diseases in various vertebrate species. As they are familiar with multifactorial health problems in single animals as well as in herd health management, their knowledge and skills can be beneficial for the beekeepers and honeybee health. However, in education and in practice, honeybees are not a common species for most veterinarians and the typical veterinary diagnostic methods such as blood sampling or auscultation are not applicable to the superorganism honeybee. Honeybee colonies may be affected by various biotic and abiotic factors. Among the infectious agents, RNA-viruses build the largest group, causing covert and overt infections in honeybee colonies which may lead to colony losses. Veterinarians could and should play a more substantial role in managing honeybee health-not limited to cases of notifiable diseases and official hygiene controls. This review discusses the veterinary diagnostic approach to adult bee examination with a special focus on diagnosis and differential diagnosis of the common virus diseases Acute Bee Paralysis Virus (ABPV)-Kashmir Bee Virus (KBV)-Israeli Acute Paralysis Virus (IAPV)-Complex, Chronic Bee Paralysis Virus (CBPV) and Deformed Wing Virus (DWV), as well as coinfections like Varroa spp. and Nosema spp.

Overt Infection with Chronic Bee Paralysis Virus (CBPV) in Two Honey Bee Colonies.

Chronic Bee Paralysis Virus (CBPV), a widespread honey bee RNA virus, causes massive worker bee losses, mostly in strong colonies. Two different syndromes, with paralysis, ataxia and flight incapacity on one hand and black hairless individuals with shortened abdomens on the other, can affect a colony simultaneously. This case report presents two Apis mellifera carnica colonies with symptoms of paralysis and hairless black syndrome in 2019. Via RT-PCR, a highly positive result for CBPV was detected in both samples. Further problems, such as a Nosema infection and Varroa infestation, were present in these colonies. Therapy methods were applied to colony 1 comprising queen replacement, shook swarm method and Varroa control, whereas colony 2 was asphyxiated after queen loss and colony weakening. After therapy, colony 1 was wintered without symptoms. Beekeeping and sanitary measures can save a CBPV-infected colony, while further complications result in total colony loss.

Gross anatomical study of the thoracolumbar primary dorsal branches and their course from the spinal cord to the skin in the cat.

The course of spinal nerves and the corresponding cutaneous areas are fundamental for numerous therapeutic approaches used in complementary veterinary medicine. Positive effects of these methods are primarily based on segmental reflex arcs which are associated with the course of the spinal nerves. In this morphological study, the lateral cutaneous branches of the thoracolumbar dorsal branches from Th9 to L7 were examined in cats with special regard to their anatomical course. A four-layer dissection was carried out to reveal the course of nerves between the intervertebral foramina and their point of entry into the skin, starting in the dorsal midline. Dorsal branch courses and covered distances were documented and measured in each layer. The covered distance was evaluated by the Caudal Shift Index (CSIn ) on both body sides and within each layer. The 'back region' was used as relative dimensional unit, describing the distance between the cranial tips of two consecutive spinous processes. Overall, the mean CSIn for dorsal branches of Th9 to L7 amounted to three back regions from the intervertebral foramen to the skin entry point of a dorsal nerve branch. This provides therapists with clues and should be put into practice, by extending the treatment area up to three segments caudally from the nerve exit point. Furthermore, the results of this study present new data on inferred lumbar dermatomes in cats, data which until now have only been transferred from other species. These results may serve as an anatomical foundation for manual therapies.

Quality and validity of large animal experiments in stroke: A systematic review.

An important factor for successful translational stroke research is study quality. Low-quality studies are at risk of biased results and effect overestimation, as has been intensely discussed for small animal stroke research. However, little is known about the methodological rigor and quality in large animal stroke models, which are becoming more frequently used in the field. Based on research in two databases, this systematic review surveys and analyses the methodological quality in large animal stroke research. Quality analysis was based on the Stroke Therapy Academic Industry Roundtable and the Animals in Research: Reporting In Vivo Experiments guidelines. Our analysis revealed that large animal models are utilized with similar shortcomings as small animal models. Moreover, translational benefits of large animal models may be limited due to lacking implementation of important quality criteria such as randomization, allocation concealment, and blinded assessment of outcome. On the other hand, an increase of study quality over time and a positive correlation between study quality and journal impact factor were identified. Based on the obtained findings, we derive recommendations for optimal study planning, conducting, and data analysis/reporting when using large animal stroke models to fully benefit from the translational advantages offered by these models.

Corrigendum: Development of a Routinely Applicable Imaging Protocol for Fast and Precise Middle Cerebral Artery Occlusion Assessment and Perfusion Deficit Measure in an Ovine Stroke Model: A Case Study.

[This corrects the article DOI: 10.3389/fneur.2019.01113.].

Modeling dermatophytosis: Guinea pig skin explants represent a highly suitable model to study Trichophyton benhamiae infections.

Dermatophyte infections are a growing health concern worldwide with increasing patient numbers, especially in children. However, detailed knowledge about infection mechanisms and virulence factors are scarce. This study aimed to establish an infection model based on guinea pig skin explants mimicking the in vivo situation as closely as possible to survey the pathogenesis of dermatophytoses. A fundamental prerequisite was the detailed description of native guinea pig skin and its morphological changes during tissue culture because comprehensive data on guinea pig skin characteristics were not available. Skin explants were harvested from healthy, adult guinea pigs and transferred to cell culture inserts. One group was inoculated with defined suspensions of colony-forming units of zoonotic Trichophyton benhamiae isolates; others served as controls to assess the tissue viability during the 10-day culture. Samples were taken on days 3, 5, 7 and 10 and processed for histological and immunohistochemical analysis. Standard tissue culture conditions provoked acantholysis and regional orthokeratotic alterations. The reduced desquamation caused hyperkeratosis paralleled by hypogranulosis or regional hyperplasia. During T. benhamiae infection, keratinocyte proliferation came to a complete halt on day 5 whereas the number of terminal deoxynucleotidyl transferase dUTP nick end labeling assay-positive cells increased moderately up to day 7. Hyphae grew massively into the skin explants causing strong keratinolysis and tricholysis. By the end of the culture, complete disintegration of the basement membrane and dermal tissue was observed. A realistic and reliable skin infection model was established to study dermatophytoses in general and cutaneous T. benhamiae infections in particular.

Development of a Routinely Applicable Imaging Protocol for Fast and Precise Middle Cerebral Artery Occlusion Assessment and Perfusion Deficit Measure in an Ovine Stroke Model: A Case Study.

Temporary middle cerebral artery occlusion (MCAO) in sheep allows modeling of acute large vessel occlusion stroke and subsequent vessel recanalization. However, rapid and precise imaging-based assessment of vessel occlusion and the resulting perfusion deficit during MCAO still represents an experimental challenge. Here, we tested feasibility and suitability of a strategy for MCAO verification and perfusion deficit assessment. We also compared the extent of the initial perfusion deficit and subsequent lesion size for different MCAO durations. The rete mirabile prevents reliable vascular imaging investigation of middle cerebral artery filling status. Hence, computed tomography perfusion imaging was chosen for indirect confirmation of MCAO. Follow-up infarct size evaluation by diffusion-weighted magnetic resonance imaging revealed fluctuating results, with no apparent relationship of lesion size with MCAO at occlusion times below 4 h, potentially related to the variable collateralization of the MCA territory. This underlines the need for intra-ischemic perfusion assessment and future studies focusing on the correlation between perfusion deficit, MCAO duration, and final infarct volume. Temporary MCAO and intra-ischemic perfusion imaging nevertheless has the potential to be applied for the simulation of novel recanalization therapies, particularly those that aim for a fast reperfusion effect in combination with mechanical thrombectomy in a clinically realistic scenario.

Large animals in neurointerventional research: A systematic review on models, techniques and their application in endovascular procedures for stroke, aneurysms and vascular malformations.

Neuroendovascular procedures have led to breakthroughs in the treatment of ischemic stroke, intracranial aneurysms, and intracranial arteriovenous malformations. Due to these substantial successes, there is continuous development of novel and refined therapeutic approaches. Large animal models feature various conceptual advantages in translational research, which makes them appealing for the development of novel endovascular treatments. However, the availability and role of large animal models have not been systematically described so far. Based on comprehensive research in two databases, this systematic review describes current large animal models in neuroendovascular research including their primary use. It may therefore serve as a compact compendium for researchers entering the field or looking for opportunities to refine study concepts. It also describes particular applications for ischemic stroke and aneurysm therapy, as well as for the treatment of arteriovenous malformations. It focuses on most promising study designs and readout parameters, as well as on important pitfalls in endovascular translational research including ways to circumvent them.