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Dive into the research topics where Hans Geyer is active.

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Featured researches published by Hans Geyer.


Veterinary Record | 2002

Suspensory structures and supporting tissues of the third phalanx of cows and their relevance to the development of typical sole ulcers (Rusterholz ulcers)

Ch.J. Lischer; P. Ossent; M. Räber; Hans Geyer

The mural suspensory apparatus of third phalanx and its supportive heel cushion were examined in 19 cows with an ulcer at the ‘typical’ site (Rusterholz ulcer) to gain information on the pathogenesis of sole and heel ulcers. The claws of 17 healthy controls were used for comparison. The left hind claws, frozen at −20°C, were sectioned in one longitudinal and four transverse planes with a band saw. The thickness of the subcutaneous tissue, the corium and the extent of displacement of the third phalanx were measured at defined sites on these sections. In addition, the suspensory apparatus, the tissue layer connecting the third phalanx to the dorsal wall of the horn capsule, was examined histologically. There was a direct relationship between the displacement of the third phalanx and ulceration of the sole or heel; in all the ulcerated claws the third phalanx had dropped and the corium and the subcutis under the bone were thinner than in the controls. The supportive cushions of the cows with ulcers contained less fat tissue. There was no histological evidence of damage to the epidermis or the corioepidermal junction in the ulcerated claws nor were the lamellae elongated. Similarly, there were no morphological changes in the connective tissue layer, the submural dermis.


Equine Veterinary Journal | 2006

Magnetic resonance imaging, ultrasonography and histology of the suspensory ligament origin : a comparative study of normal anatomy of Warmblood horses

Andrea S. Bischofberger; M Konar; Stefanie Ohlerth; Hans Geyer; Johann Lang; Gottlieb Ueltschi; Christoph Lischer

REASONS FOR PERFORMING STUDY The diagnosis of lameness caused by proximal metacarpal and metatarsal pain can be challenging. Magnetic resonance imaging (MRI) offers the possibility for further diagnosis but there have been no studies on the normal MRI appearance of the origin of the suspensory ligament (OSL) in conjunction with ultrasonography and histology. OBJECTIVES To describe the MRI appearance of the OSL in fore- and hindlimbs of sound horses and compare it to the ultrasonographic and histological appearance. The findings can be used as reference values to recognise pathology in the OSL. METHODS The OSL in the fore- and hindlimbs of 6 sound horses was examined by ultrasonography prior to death, and MRI and histology post mortem. Qualitative evaluation and morphometry of the OSL were performed and results of all modalities compared. RESULTS Muscular tissue, artefacts, variable SL size and shape complicated ultrasonographic interpretation. In MRI and histology the forelimb OSL consisted of 2 portions, the lateral being significantly thicker than medial. The hindlimb SL had a single large area of origin. In fore- and hindlimbs, the amount of muscular tissue was significantly larger laterally than medially. Overall SL measurements using MRI were significantly higher than using histology and ultrasonography and histological higher than ultrasonographic measurements. Morphologically, there was a good correlation between MRI and histology. CONCLUSIONS MRI provides more detailed information than ultrasonography regarding muscle fibre detection and OSL dimension and correlates morphologically well with histology. Therefore, ultrasonographic results should be regarded with caution. POTENTIAL RELEVANCE MRI may be a diagnostic aid when other modalities fail to identify clearly the cause of proximal metacarpal and metatarsal pain; and may improve selection of adequate therapy and prognosis for injuries in this region.


Schweizer Archiv Fur Tierheilkunde | 2010

[Feed-related selenium poisoning in swine].

M. Räber; T. Sydler; U. Wolfisberg; Hans Geyer; E. Bürgi

The following case report describes a selenium toxicosis in a pig-fattening farm of two finisher groups. The diseased animals partly showed ataxia and paresis or intense lameness in connection with band-like ablation of the epidermis at the coronary band. Some of them suffered from alopecia. Foot-and-mouth disease and swine vesicular disease were excluded by serological tests. Dissection revealed a multifocal bilateral symmetric poliomyelomalacia. Histological changes in the claws ranged from severe cell-decay in the germinative layer to distinctive decay of the stratum corneum. Due to damage of the claw epidermis the corium was partly exposed. Feed analysis revealed 100-fold increased selenium content in the finishing premix from the feed mill and as a result 20- to 60-fold increased selenium values in feed samples from the farm-made finisher mixture. Selenium concentration in the blood of diseased animals was 4- to 10-fold higher than normal values, which confirmed the tentative diagnosis of a selenium toxicosis.


Veterinary Surgery | 2012

Medial Humeral Epicondylitis in Cats

Ronny Streubel; Hans Geyer; Pierre M. Montavon

Objective To describe medial humeral epicondylitis in cats based on radiographic, anatomic, and histologic observations. Study Design Prospective cohort study. Animals Feline cadavers (n = 60). Methods Extended craniocaudal, and extended and flexed mediolateral radiographic projections were taken of both elbows of 60 consecutive European shorthair cats that died or were euthanatized. Elbows with new bone formation at the medial epicondyle were dissected and embedded in methyl-methacrylate (MMA). For comparison, both elbows of a cat with no radiographic changes were prepared in a similar manner. Sections of the MMA blocks were Giemsa stained and examined with light microscopy. Results Bilateral new bone formation was identified radiographically at the medial aspect of the humeral epicondyle in 6 cats (10%). All of these cats had mineral deposition in the humeral head of the flexor carpi ulnaris muscle. Other findings were cartilage damage (n = 3 cats), an additional loose medial joint body (1), and tendinosis (3). The ulnar nerve was flattened and displaced caudally, and signs of chronic epineural fibrosis were present in 2 severely affected cats. Conclusions Ten percent of this feline population had radiographic evidence of medial humeral epicondylitis with chronic degeneration, mineralization, and metaplastic bone formation in damaged fibrillar matrix involving the origin of the humeral head of the flexor carpi ulnaris muscle. New bone formation caused displacement and compression of the ulnar nerve in severely affected elbows. Based on our findings, medial humeral epicondylitis appears to be a common disorder in cats with potential clinical sequelae.OBJECTIVE To describe medial humeral epicondylitis in cats based on radiographic, anatomic, and histologic observations. STUDY DESIGN Prospective cohort study. ANIMALS Feline cadavers (n = 60). METHODS Extended craniocaudal, and extended and flexed mediolateral radiographic projections were taken of both elbows of 60 consecutive European shorthair cats that died or were euthanatized. Elbows with new bone formation at the medial epicondyle were dissected and embedded in methyl-methacrylate (MMA). For comparison, both elbows of a cat with no radiographic changes were prepared in a similar manner. Sections of the MMA blocks were Giemsa stained and examined with light microscopy. RESULTS Bilateral new bone formation was identified radiographically at the medial aspect of the humeral epicondyle in 6 cats (10%). All of these cats had mineral deposition in the humeral head of the flexor carpi ulnaris muscle. Other findings were cartilage damage (n = 3 cats), an additional loose medial joint body (1), and tendinosis (3). The ulnar nerve was flattened and displaced caudally, and signs of chronic epineural fibrosis were present in 2 severely affected cats. CONCLUSIONS Ten percent of this feline population had radiographic evidence of medial humeral epicondylitis with chronic degeneration, mineralization, and metaplastic bone formation in damaged fibrillar matrix involving the origin of the humeral head of the flexor carpi ulnaris muscle. New bone formation caused displacement and compression of the ulnar nerve in severely affected elbows. Based on our findings, medial humeral epicondylitis appears to be a common disorder in cats with potential clinical sequelae.


Schweizer Archiv Fur Tierheilkunde | 2005

Anatomie der Griffelbeine und ihrer Umgebung unter besonderer Berücksichtigung der Faszien

Michelle Amanada Jackson; Hans Geyer; Anton Fürst

Diese Arbeit untersucht die Ossa metacarpalia/Ossa metatarsalia II und IV beim Pferd und im Besonderen die Weichteilgewebe um die Griffelbeine. Dabei wurden die Fascia metacarpi palmaris/Fascia metatarsi plantaris, die Ligamenta metacarpea/metatarsea interossea und die Faserbundel, welche distal vom Griffelbeinknopfchen entspringen, anatomisch genau beschrieben. Die Gliedmassen von 5 geschlachteten oder euthanasierten Pferden wurden gesammelt und sowohl makroskopisch als auch mikroskopisch untersucht. Die Fascia metacarpi palmaris/Fascia metatarsi plantaris stellte sich als eine sehr stabile Struktur dar, welche die Griffelbeine fest mit der Umgebung verbindet. Die Ligamenta metacarpea/metatarsea interossea, welche die Verbindung zwischen Griffelbeinen und Rohrbein darstellen, zeigen erhebliche Unterschiede von Pferd zu Pferd. Makroskopische Untersuchungen des Weichteilgewebes distal an den Griffelbeinen zeigt eine Bandstruktur, die am Griffelbeinknopfchen entspringt und in dorso-distaler Richtung verlauft.


Pferdeheilkunde | 2006

Der Einfluss von Zügel und Gebiss auf die Bewegungen des Pferdes - anatomisch-funktionelle Betrachtungen

Hans Geyer; M. A. Weishaupt

The paper gives an overview about reins and bits and their influence on the movements in horses. Based on anatomical specimens and resulting schematic drawings the various influences of bits and reins including recent results of forces, measured by some authors are described. The great variability in bits and reins makes it very difficult to judge their influence. The bit produces forces in ventral, dorsal and caudal direction. The ventral forces may damage the lower jaw. Especially the caudally directed forces hold up the anterior movement of the horse and areas as the temporomandibular joint, the neck and the caudal cervical joints may be areas of high load. There, rein forces are acting, which are considerably amplified by lever forces. The high forces induced by the levers of the curb or other bridles as the draw rein are pointed out. The bitless bridles may induce also pressure to sensitive areas as nose, neck or lower jaw. The most important nerves, which can be irritated by bits or bitless bridles are shown. The sensitive hand of the rider is able to avoid pain and damage to the horses head and enables controlled, but not restricted movements.


Veterinary Record | 2009

Neurological signs in pigs supplemented orally with pharmacological amounts of B vitamins from one to 10 months of age

A. Gutzwiller; G. Bee; W. Zimmermann; Anna Oevermann; G. Wyss-Fluehmann; M. Räber; Hans Geyer; M. H. Braunschweig

THE only vitamins known to be neurotoxic in human beings when ingested in excess of requirements are vitamins A and B6 ([Snodgrass 1992][1]). The neurological manifestations of vitamin B6 intoxication resemble those of vitamin B6 deficiency, presumably because the tissue level of pyridoxal phosphate


Schweizer Archiv Fur Tierheilkunde | 2008

Einfluss einer hohen Selenzufuhr auf den Selenstatus, die Leberfunktion und auf die Klauenqualität von Maststieren

M. Räber; Hans Geyer; J. Kessler; A. Gutzwiller

The effects of three dietary selenium (Se) levels (0.15, 0.35 and 0.5 mg/kg dry matter (dm) and of two Se-compounds (sodium selenite and Se-yeast) on the Se-status, liver function and claw health were studied using 36 fattening bulls in a two-factorial feeding trial that lasted 16 weeks. The claw health was assessed macroscopically and microscopically. Compared to the two control diets containing 0.15 mg Se/kg dm, the intake of the diets containing 0.35 and 0.50 mg Se/kg dm significantly (P 0.1) on growth and liver function parameters. With the exception of the decrease of the serum vitamin E level indicating an oxidative stress caused by a high Se-intake, no negative effects of dietary selenium exceeding recommended levels for 4 months were observed.


Journal of Feline Medicine and Surgery | 2017

Association of mineralisations in the stifle joint of domestic cats with degenerative joint disease and cranial cruciate ligament pathology.

Katja Voss; Philemon Karli; Pierre M. Montavon; Hans Geyer

Objectives The aim of the study was to evaluate the prevalence, size, location and appearance of mineralisations in feline stifle joints, and to evaluate their relationship with osteoarthritis and cranial cruciate ligament (CrCL) status. Methods Presence or absence, and size of mineralisations were determined from lateral stifle radiographs of 25 cats with CrCL rupture, and 44 cat cadavers without CrCL rupture. Mineralisations were classified as small, medium or large. Prevalence was compared between the clinically affected cats and the cadavers; the cadaver group was subdivided into an age-matched and an older group. Ten stifles with varying sizes of mineralisations were prepared as whole-knee specimens for histopathology. Location and appearance of the mineralisations, and degenerative changes in the cruciate ligaments, menisci, articular cartilage and joint capsule are described. Results Prevalence of articular mineralisations was 0.76 in stifles of cats with CrCL rupture (mean ± SD age 8.6 ± 4.5 years), 0.64 in stifles of age-matched cat cadavers and 0.74 in older cat cadavers (mean ± SD age 17.0 ± 2.4 years). Cats with CrCL rupture had a higher percentage of medium and large mineralisations than cats without CrCL rupture. Microscopically, small mineralisations were calcifications usually located in the cranial horn of the medial meniscus. Larger mineralisations were found to be ossifications, commonly located in the joint capsule and fat pad. Cats with larger mineralisations showed more signs of osteoarthritis, including degenerative changes in the CrCL. Conclusions and relevance Mineralisations in feline stifle joints were found to differ in size, appearance and location. Small mineralisations were usually confined to the medial meniscus, as described previously; larger mineralisations tended to be located in the tissues cranial to the menisci and seemed to be associated with osteoarthritis and CrCL pathology. Large mineralisations in feline stifles are ossifications in periarticular tissue and are associated with degenerative joint disease.


Journal of Veterinary Dentistry | 2016

Measuring rabbit (Oryctolagus cuniculus) tooth growth and eruption by fluorescence markers and bur marks

Fabia Wyss; Jacqueline Müller; Marcus Clauss; Patrick R. Kircher; Hans Geyer; Brigitte von Rechenberg; Jean-Michel Hatt

Rabbits (Oryctolagus cuniculus) and rodents possess continuously growing teeth, and dental problems are a major health issue in these species. Knowledge of tooth growth characteristics is required to adequately treat dental problems and advise owners concerning diets. Most research was performed using bur marks and measuring eruption and wear manually. However, this method cannot be applied to teeth less rostral than the first premolar; therefore, for evaluation of molars, other methods are needed. We evaluated the use of fluorochromes xylenol orange and calcein green to measure growth rates of rabbit teeth and compared this method to results obtained by manually measuring the distance between a bur mark and the gingival margin of the same tooth (eruption) and by measuring the distance between the bur mark and the apex of the same tooth on computed tomography scans (growth). Apical fluorochrome measurements correlated well with eruption and growth rates obtained with bur marks, whereas measurements coronal to the pulp cavity did not. Growth rates were approximately 1.9 mm/wk for maxillary and 2.2 mm/wk for mandibular incisors. Growth rates of premolars were 2.14 ± 0.28 mm/wk in rabbits on a grass/rice hulls/sand pelleted diet and 0.93 ± 0.18 mm/wk in rabbits on a hay diet. Growth of molars could only be assessed using the measurement in dentin on the wall of the pulp cavity, which does not account for the real growth. However, being similar to this measurement in premolars, one could hypothesize similar growth in molars as in premolars. We conclude that the application of fluorochrome staining can be used to measure tooth growth in teeth that are not accessible for bur marks or in animals that are too small to assess tooth eruption or growth by bur marks.

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M Kummer

University of Zurich

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