Stephan Handschuh

University of Veterinary Medicine, Vienna | vetmed · VetCORE – Facility for Research

In comparison to more modern imaging methods, conventional light microscopy still offers a range of substantial advantages with regard to contrast options, accessible specimen size, and resolution. Currently, tomographic image data in particular is most commonly visualized in three dimensions using volume rendering. To date, this method has only ve...

In biomedical research, a huge variety of different techniques is currently available for the structural examination of small specimens, including conventional light microscopy (LM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), microscopic X-ray computed tomography (microCT), and many others. Since every imagin...

Dual-energy computed tomography (DECT) uses two different x-ray energy spectra in order to differentiate between tissues, materials or elements in a single sample or patient. DECT is becoming increasingly popular in clinical imaging and preclinical in vivo imaging of small animal models, but there have been only very few reports on ex vivo DECT of...

For decades, clearing and staining with Alcian blue and alizarin red has been the gold standard to image vertebrate skeletal development. Here we present an alternate approach to visualise bone and cartilage based on X-ray microCT imaging, which allows obtaining genuine 3D data of the entire developing skeleton at micron resolution. Our novel proto...

Ex vivo x‐ray angiography provides high‐resolution, three‐dimensional information on vascular phenotypes down to the level of capillaries. Sample preparation for ex vivo angiography starts with the removal of blood from the vascular system, followed by perfusion with an x‐ray dense contrast agent mixed with a carrier such as gelatine or a polymer....

Ticks are composed of 3 extant families (Argasidae, Ixodidae and Nuttalliellidae) and 2 extinct families (Deinocrotonidae and Khimairidae). The Nuttalliellidae possess one extant species (Nuttalliella namaqua) limited to the Afrotropic region. A basal relationship to the hard and soft tick families and its limited distribution suggested an origin f...

Body morphologies are significantly different amongst the members of the Drusinae subfamily. Aligned with such differences is the selective niche location chosen by many species from the subfamily. Typically, they live on the sediments of cold, well-oxygenated mountain streams from the Eurasian Region. However, each of the three evolutionary lineag...

Giant African land snails (GALS) have become increasingly popular, for example, as pets or in kindergartens in Europe, but little is known about their clinically relevant anatomy, diseases, or further details in diagnostic imaging. The present study focuses on the techniques and image interpretation of radiography, computed tomography, and sonograp...

Small terminal branches of the root canal in mammals can form a so-called apical delta (AD). Morphological configuration and variability of this apical canal system can affect endodontic treatment success. Although ADs are more prevalent in permanent dentition of dogs than in humans, little is known about 3D appearance and complexity. The present s...

Objective: To determine the morphology and volume of Meibomian glands (MG) of dogs with microCT before and after partial tarsal plate excision (PTPE), cryotherapy, and laser therapy. Procedure: MicroCT scans were made of 12 upper lids (ULs) and lower lids (LLs) of 12 dogs. After undergoing PTPE, 10 ULs and LLs were scanned again, and one UL and...

Chemical staining of biological specimens is commonly utilised to boost contrast in soft tissue structures, but unambiguous identification of staining location and distribution is difficult without confirmation of the elemental signature, especially for chemicals of similar density contrast. Hyperspectral X-ray computed tomography (XCT) enables the...

Three examples of metastriate hard ticks (Ixodida: Ixodidae) with apparent affinities to modern Australasian genera are described from the mid-Cretaceous (ca. 100 Ma) Burmese amber of Myanmar. Two nymphs of Bothriocroton muelleri sp. nov. represent the oldest (and only) fossil record of this genus, living members of which are restricted to Australi...

Objective: To describe in detail the arterial vasculature of metacarpophalangeal joints 2-5 on cadaver specimens and to compare it to ultrasound imaging of healthy subjects. Methods: Eighteen hands of donated human cadavers were arterially injected and investigated with either corrosion casting or cryosectioning. Each layer of cryosectioned specim...

This study explored the use of X-ray computerized microtomography (micro-CT) and confocal Raman microscopy to provide complementary information to well-established techniques, such as confocal laser scanning microscopy (CLSM), for the microstructural characterization of cheese. To evaluate the potential of these techniques, 5 commercial Cheddar che...

Microscopic X-ray computed tomography (microCT) is a structural ex vivo imaging technique providing genuine isotropic 3D images from biological samples at micron resolution. MicroCT imaging is non-destructive and combines well with other modalities such as light and electron microscopy in correlative imaging workflows. Protocols for staining embryo...

The seal heartworm Acanthocheilonema spirocauda (Nematoda: Onchocercidae) parasitizes the heart and pulmonary arteries of various phocid seals of the Northern Hemisphere. Over many decades, potential vectors of this parasite have been discussed, and to this date, the life cycle is not fully known. The seal louse Echinophthirius horridus (Anoplura:...

Here, we describe a workflow for high‐detail microCT imaging of formalin‐fixed and paraffin‐embedded (FFPE) equine embryos recovered on Day 34 of pregnancy (E34), a period just before placenta formation. The presented imaging methods are suitable for large animals' embryos with intention to study morphological and developmental aspects, but more ge...

Four fossil ticks (Arachnida: Parasitiformes: Ixodida) are described from mid-Cretaceous (ca. 100 Ma) Burmese amber of Myanmar. Ixodes antiquorum sp. nov. (Ixodidae) is the first Mesozoic record of Ixodes and the oldest representative of the most species-rich extant tick genus. Its affinities appear to lie with modern Australian forms, consistent w...

The subfamily Drusinae (Limnephilidae, Trichoptera) comprises a range of species exhibiting differently shaped head capsules in their larval stages. These correspond to evolutionary lineages pursuing different larval feeding ecologies, each of which uses a different hydraulic niche: scraping grazers and omnivorous shredders sharing rounded head cap...

Tusk fracture in elephants is a common incident often resulting in pulp exposure and pulpitis. Extensive lavage, endodontic therapy, direct pulp capping, or extraction are treatment options. In this report, the successful management of a broken tusk of a juvenile male Asian elephant (Elephas maximus) including morphological analysis of the tusk tip...

Here we apply hyperspectral bright field imaging to collect computed tomographic images with excellent energy resolution (~ 1 keV), applying it for the first time to map the distribution of stain in a fixed biological sample through its characteristic K-edge. Conventionally, because the photons detected at each pixel are distributed across as many...

It was the aim of this study to characterize the development of the gonads and genital ducts in the equine fetus around the time of sexual differentiation. This included the identification and localization of the primordial germ cell population. Equine fetuses between 45 and 60 days of gestation were evaluated using a combination of micro-computed...

Objective Transplantation of minor salivary glands (MSGs) to the conjunctiva is a treatment option for patients suffering from dry eye disease. As there is not enough information about labial and buccal MSGs in dogs, the aim of this study was to provide evidence of the presence of these glands and to investigate their spatial arrangement and excret...

It was the aim of this study to provide a more precise timeframe of development of the gonads and genital ducts in the equine fetus around the time of sexual differentiation. This included the identification and localisation of the primordial germ cell population. Equine fetuses between 45 and 60 days of gestation were evaluated using a combination...

A sample of 30 thick-shelled river mussels Unio crassus Philipsson (Unionida: Unionidae) was collected from the River Sauer in Luxembourg to acquire data on parasitic infestations of the mussels. Among other parasites, different development stages of freshwater mites were collected from the gills and the mantle of the mussels and were documented wi...

The subfamily Drusinae (Limnephilidae, Trichoptera) comprises a range of species exhibiting differently shaped head capsules in their larval stages. These correspond to evolutionary lineages pursuing different larval feeding ecologies, each of which uses a different hydraulic niche: scraping grazers and omnivorous shredders sharing rounded head cap...

Hippocampal changes in epilepsy may manifest as hippocampal atrophy/sclerosis. A recent human study suggests that the demonstration of hippocampal volume loss is more reliable using quantitative evaluation methods. The aim of the present study was to obtain volumetric data in both epileptic and healthy dogs, to compare hippocampal volumes in both g...

As the longissimus dorsi muscle is the largest muscle in the equine back, it has great influence on the stability of the spine and facilitates proper locomotion. The longissimus muscle provides support to the saddle and rider and thereby influences performance in the horse. Muscular dysfunction has been associated with back disorders and decline of...

Micro-computed tomography (microCT) of small animals has led to a more detailed and more accurate three-dimensional (3D) view on different anatomical structures in the last years. Here, we present the cranial anatomy of two frog species providing descriptions of bone structures and soft tissues of the feeding apparatus with comments to possible rel...

External and internal head anatomy of drusus monticola trichoptera limnephilidae: Caddisflies have evolved to a staggering diversity, and their larvae inhabit a wide range of different habitats. Also, the larvae differ in their (feeding) ecology, and hydrological niche preference. Consequently, groups differ in their external morphology, a fact th...

Here we apply hyperspectral bright field imaging to collect computed tomographic images with excellent energy resolution (800 eV), applying it for the first time to map the distribution of stain in a fixed biological sample through its characteristic K-edge. Conventionally, because the photons detected at each pixel are distributed across as many a...

Hydraulic niche descriptors of final instar larvae of nine Drusus species (Trichoptera) were studied in small, spring-fed, first-order headwaters located in the Mühlviertel (Upper Austria), Koralpe (Carinthia, Austria), and in the Austrian and Italian Alps. The species investigated covered all three clades of Drusinae: the shredder clade (Drusus fr...

By studying hydraulic stress parameters of larvae of the cased caddisfly Drusus biguttatus (Pictet, 1834) in a tributary of the Schwarze Sulm (Carinthia, Austria), we aimed on (1) detecting the flow properties of the spatio-temporally filtered velocity measurements taken, and (2) on defining the hydraulic niche of this caddisfly larva. For this, we...

Bone metastases are a frequent complication of cancer and are associated with considerable morbidity. Bones provide a permissive environment for metastatic colonization due to their dynamic turnover and an abundance of secreted factors that are required for bone maintenance. Insulin-like growth factors (IGF) are the most abundant growth factors in...

Tissue vibrations in the larynx produce most sounds that comprise vocal communication in mammals. Larynx morphology is thus predicted to be a key target for selection, particularly in species with highly developed vocal communication systems. Here, we present a novel database of digitally modeled scanned larynges from 55 different mammalian species...

In horses, low postovulatory progestin concentrations delay downregulation of endometrial progesterone receptors, impairing histotroph composition. The aim of this study was to evaluate conceptus development until placentation in mares under experimentally reduced progestin concentrations in the early postovulatory phase. Eleven mares were insemina...

Coniopterygidae are the dwarfs among the Neuroptera. Despite their miniaturisation, the males are equipped with genital sclerites that are excessively heterogeneous. They function in copulation and sperm transfer and have been widely utilized for species identification, as well being considered of high phylogenetic relevance. The present study is t...

A new Drusinae species, Drusus katagelastos sp. nov., of the Drusus chapmani Species Complex, is described based on a male and associated larvae. Adult-larval association was achieved through DNA barcoding. The male of the new species differs from that of its congeners in the formation of the intermediate appendages and parameres. Information on th...

Micro-computed tomography (micro-CT) imaging currently gains increased interest in human as well as veterinary medicine. The ability to image 3-dimensional (3D) biopsy specimens nondestructively down to 1 µm spatial resolution makes it a promising tool for microscopic tissue evaluation in addition to histopathology. Visualizing tumor margins and ca...

Objectives The aim of our study was to compare the standard fabellotibial suture with Mini TightRope fixation for the treatment of a cranial cruciate ligament (CCL) rupture using a feline custom-made limb press. Methods Cadaveric hindlimbs of 10 cats were inserted in the limb press at predefined joint angles and loads of 10% and 30% body weight (BW...

The frontiers of bioimaging are currently being pushed toward the integration and correlation of several modalities to tackle biomedical research questions holistically and across multiple scales. Correlated Multimodal Imaging (CMI) gathers information about exactly the same specimen with two or more complementary modalities that—in combination—cre...

During the early luteal phase, low progesterone concentrations delay downregulation of endometrial progesterone receptors. This contributes to impaired histotroph production at Day 14 of pregnancy (Beyer et al. 2019 Theriogenology 125, 236-241). Until the beginning of placentation (i.e. Day 37 of pregnancy), nutritional supply of the equine concept...

The ING3 candidate tumour suppressor belongs to a family of histone modifying proteins involved in regulating cell proliferation, senescence, apoptosis, chromatin remodeling, and DNA repair. It is a stoichiometric member of the minimal NuA4 histone acetyl transferase (HAT) complex consisting of EAF6, EPC1, ING3, and TIP60. This complex is responsib...

This paper summarizes the layout, the three work packages and the intended outcome of the project 'Intricate bodies in the boundary layer P 31258-B29', funded by the Austrian Science Fund (FWF ; project start: October 2018).

Cells use different cell adhesion and communication structures to promote tissue development, maintenance of tissue integrity as well as repair and regenerative processes. Another recently discovered way of information exchange is long‐distance thin cellular processes called nanotubes (NTs), mainly studied in vitro. Information on the existence and...

Der Bereich der apikalen Zahnwurzelkanäle beim Säugetier ist vielgestaltig. So können kleine terminale Aufzweigungen des Wurzelkanals ein sogenanntes apikales Delta (AD) bilden1,2,3. Frühere Untersuchungen konnten zeigen, dass das AD beim Hund wesentlich komplexer gestaltet ist als beim Menschen und im permanenten Gebiss mit gravierend höherer Präv...

We developed a finite element model (FEM) of the equine stifle joint to identify pressure peaks and simulate translocation and deformation of the menisci. A series of sectional magnetic resonance images (1.5 T) of the stifle joint of a 23 year old Shetland pony gelding served as basis for image segmentation. Based on the 3D polygon models of femur,...

Plankton serve as one of the primary bases of the marine food chain and are as a result a crucial component of Earth's ecosystem. Project Noise Aquarium deals with unnatural noise in the oceans largely associated with fossil fuels as an environmental issue. This project offers a species-rich idyll as well as visual attractiveness, thus evoking inte...

3D root canal geometry and apical ramification of canine teeth in dogs

Three-dimensional (3D) root canal morphology and apical ramification (apical deltas) creates some technical difficulties during orthograde root canal therapy in both, human and veterinary dentistry. Smooth tapered shaping of a well-centered canal, maintenance of the original root canal curvature and apical obturation represents a key procedure in c...

Objective: To design and evaluate a new vestibular implant and surgical procedure that should reach correct electrode placement in 95% of patients in silico. Design: Computational anatomy driven implant and surgery design study. Setting: Tertiary referral center. Participants: The population comprised 81 patients that had undergone a CT scan...

Background Progressive transformation of the otic placode into the functional inner ear during gestational development in humans leads to the acquisition of hearing perception via the cochlea and balance and spatial orientation via the vestibular organ. Results Using a correlative approach involving micro-computerized tomography (micro-CT), transm...

Cranial kinesis refers to intracranial movements in the vertebrate skull that do not concern the jaw joint, the middle ear or the hypobranchial skeleton. Different kinds of cranial kinesis have been reported for lizards, including mesokinesis, metakinesis, amphikinesis (simultaneous mesokinesis and metakinesis) and streptostyly. Streptostyly is con...

Objective To evaluate 2 surgical techniques for establishing and/or improving paranasal sinus drainage in cadaver heads and horses with sinusitis and evaluate the feasibility of postoperative transnasal sinus endoscopy. Study design Ex vivo study (equine cadaver heads) and case series. Sample population Nine adult equine cadaver heads and 8 horse...

Aim: The aim of this study is to investigate the penetration abilities of a commercially available low-viscosity resin infiltrant into developmentally hypomineralized teeth in vitro. Materials and methods: Four extracted third molars of a 17-year-old patient with signs of developmental enamel hypomineralization (discoloration, increased opacity,...

In the equine embryo, putative primordial germ cells appear between 20 and 30 days and the gonadal primordium can first be identified at Day 30 after ovulation, respectively. Subsequently, sexual differentiation of the gonad occurs and completes by Day 45 of pregnancy. The objectives of this work were to describe the morphology and function of the...

Males from numerous animal taxa have evolved strategies for obstructing the female genitalia with copulatory plugs, reducing the risk of sperm competition and thus resulting in an advantage in sexual selection. Several lines of evidence suggest that sperm competition is a common feature in the complex squid mating systems, which include the evoluti...

Design and implantation of bionic implants for restoring impaired hair cell function relies on accurate knowledge about the microanatomy and nerve fiber pathways of the human inner ear and its variation. Non-destructive isotropic imaging of soft tissues of the inner ear with lab-based microscopic X-ray computed tomography (microCT) offers high reso...

Garra barreimiae (Fowler and Steinitz, Bull Res Counc Isr 5B:262–289, 1956) is a freshwater fish that lives throughout the Hajar Mountains of Oman and the United Arab Emirates. Previously, four different genetic clades (West clade, Central Clade, North clade and East clade) have been identified within this species. This study observes morphological...

Key messages: Experimental myocardial infarction (MI) augments cardiac RANKL expression in mice. RANKL expression is increased in cardiomyocytes and scar-infiltrating cells after MI. Global or mesenchymal cell RANKL inhibition has no influence on cardiac function after MI. Inhibition of RANKL derived from hematopoietic cells improves heart functio...