Magnetic resonance imaging of plantar soft tissue structures of the tarsus and proximal metatarsus in foals and adult horses.

OBJECTIVES: The object of this study was to describe previously defined soft tissue structures by using spin and gradient sequences in a 0.5 Tesla magnetic resonance system in order to improve the characterisation of tendon and ligaments at the plantar region of the equine tarsus and metatarsus while considering possible age-related variations. METHODS: Cadaveric hindlimbs from twenty-two Warmblood horses with an age range from one month to twenty-five years were examined in spin and gradient echoes. The proximal suspensory ligament from six limbs was dissected to assign the signal intensities histologically. For statistical analysis, horses were divided into two groups (≤3 years and >3 years) for evaluating signal intensity and homogeneity of the plantar tendons and ligaments. RESULTS: Focal increase of the signal intensity within the deep digital flexor tendon was significantly more present in horses older than three years. Signal alterations of the long plantar ligament were seen without a significant dependency to age. The accessory ligament of the deep digital flexor tendon could not be visualized on all images within the region of interest. The morphology of the proximal suspensory ligament was not affected by age-related changes. CLINICAL RELEVANCE: Spin and gradient echoes in MRI were suitable to identify and assess soft tissue structures at the plantar aspect of the equine tarsus and proximal metatarsus. Age-related appearance must be considered when interpreting magnetic resonance images.

Fate of sympathetic trunk ganglia after cutting in German meat plants.

To minimize risks from pathogenic prion proteins, particular tissues from bovines and other ruminants have been declared specified risk materials (SRMs), which are required to be removed from the food chain. However, in particular for the sympathetic trunk (ST) as a part of the autonomous nervous system (ANS), which represents a potential transfer route for abnormal prion proteins (PrP(Sc)), this is not the case. Consequently, its destination during cutting procedures deserves attention. In this survey, the handling of the ST in beef cutting plants was recorded during ongoing work. To ease these observations, the ST was separated into five parts, and eight destinations for cuts were identified. By means of an observation sheet, the destination of the respective tissue was recorded. About one-third of the ST went into human consumption, another one-third was disposed of as SRMs, and the last one-third was used for nonfood purposes or disposed of. The rear thoracic and sacral ganglia primarily remained naturally connected to the bones going as SRMs. The stellate, front thoracic, and lumbar ganglia went in a different percent into the food chain. Frequently, workers in the same plant decided differently, even from case to case, on the destination of the tissue, which indicates a lack of standardization.

Membrane-coating granules and the intercellular cementing substance (membrane-coating material) in the epidermis in different regions of the equine hoof.

This study aimed to carry out a comprehensive morphological examination of the structure and ultrastructure of the membrane-coating granules (MCG) and membrane-coating material (MCM) common to all hoof segments as well as segment-specific features in the MCG and MCM regarding their synthesis, structure and biochemical composition. Tissue samples from the hooves of the left front and right hind limb of 20 adult riding horses were used. Samples were preserved and embedded for histological routine methods as well as for histochemical techniques and tracer techniques for light and electron microscopy. The MCM shows a segment-specific structure, biochemical composition and function, which were demonstrated for the different parts of the hoof. The MCM and its properties are related to the segment-specific horn quality. Besides intercellular structural factors the MCM is of major importance for the structural integrity and the biomechanical properties of the hoof horn. The physiological structure and composition of MCM provides explanation for the existence of clinically well-known sites of predilection for hoof disorders such as the White Line Disease. Alterations of the MCM play a role in dysfunction and diseases of the hoof epidermis; they are particularly involved in the pathogenesis of infectious diseases of the hoof.

On the structure of the adrenal gland of the common seal (Phoca vitulina vitulina).

The adrenal gland is a vitally important endocrine gland that occupies a central role in the regulatory mechanisms of the body metabolism. Environmental stress factors lead to permanent strain and overload of the body resulting in structural alterations of the adrenals that in turn are followed by hormonal imbalances. This leads to an increased susceptibility to bacterial and viral diseases. The recurrence of numerous fatalities in the different seal populations of the North Sea (during the years 1988, 1989 and 2002), of the Baikal Lake and Caspian Sea (during the years 2000 and 2001) were the motive for a morphological investigation of the species-specific structure of the adrenal gland of the common seal in order to differentiate environmental stress-induced pathological alterations from the physiological structure of this organ. The study was based on adrenals of 112 common seals (Phoca vitulina vitulina) using light microscopic and transmission and scanning electron microscopic methods. The phocine adrenal gland displays several structural characteristics. Originating from the connective tissue organ capsule, narrow and broad septa intersperse the adrenal cortex. These septa contain blastemata as a reserve for the regeneration of hormone-producing cortical cells. Such blastemata are also occurring in the form of an intermediate zone in between the zona glomerulosa and zona fasciculata in the phocine adrenal cortex. Another species-specific characteristic is an inverse part of the adrenal cortex encircling the central vein of the organ. These structural features have to be considered in assessment and definition of pathological alterations of the adrenals as observed in the form of exhausted blastema cell pools in the adrenocortex of seals perished in the mentioned phocine mass mortalities.

[Structure and clinical implications of the coronary horn stratification with special consideration of horn maturation, aging and decay processes in the equine hoof]. / Struktur und klinisch-funktionelle Bedeutung der Kronhornstratifikation unter besonderer Berücksichtigung von Hornreifung, -alterung und -zerfall am Pferdehuf.

The three superimposing strata of the coronet and the ageing process and decay of the hoof horn were studied in 56 fore hooves of 28 domestic horses of different age and sex. Except for horn clefts at the weight bearing margin, their hooves did not show any signs of pathological changes. Their hooves did not show any signs of pathological changes. The investigation comprised the analysis of the structure and the mechanical-physical measurement of horn hardness. The own results showed that the functional and clinical importance of the three strata of the coronet concerns the absorption and distribution of the horizontal and vertical pressure and the resilient-elastical fixatia of the suspensory apparatus of the coffin bone to the inner spongiforme Stratum medium. Disruptive pathological changes may spread out between the different horn layers which sometimes leads to the phenomenon of the "Hollow Wall". The hard and stable coronet is composed of tubular and intertubular horn. Distal of the crest of the coffin bone the horn hardness decreases and clefts are visible which are interpreted as ageing processes. The medullar horn decays much faster in certain regions, thus enabling ascending infections especially in the white line area, causing "White Line Disease". Under consideration of the references the own results proved, that regular and professional trimming of the hoof can prevent these diseases and improves the pododermal blood circulation and the orthokeratotic cornification. By improving the stable hygiene and adequate nutritional supply with minerals and vitamins these measures can be supported.

Autonomous nervous system with respect to dressing of cattle carcasses and its probable role in transfer of PrP(res) molecules.

Pathogen prions are widely recognized as the causative agent in bovine spongiform encephalopathy (BSE) and other transmissible spongiform encephalopathies. However, more research on the possible transmission mutes of this agent once it has reached the host is needed. There is evidence based on the anatomy and physiology of the autonomous nervous system (ANS), as well as observations for different animal species, that the ANS might be involved in the axonal drainage of pathogen prions toward the central nervous system. In this context, more attention should be paid to the cranial cervical ganglion, the stellate ganglion, the chain of paravertebral ganglia next to the first six thoracic vertebrae, the chain of the paravertebral ganglia next to loin vertebrae 1 through 6, the vagus nerve in the neck region and in the mediastine, and the esophagus (because of its close connection to the vagus nerve). For a more detailed risk analysis with respect to these tissues, the ANSs of animals having shown clinical signs of BSE might be examined to corroborate the evidence presented here. In the meantime, as a precautionary measure, the tissue addressed should be taken out of the human food chain, taken out of animal feed, and handled as if it were specified risk material. It is technically possible to remove these parts during cutting and dressing.

Topography, structure and function of the patella and the patelloid in marsupials.

The patella is a sesamoid bone that is found in most mammals and is regularly located in the insertion tendon of the quadriceps femoris muscle. Up to now, only a little has been known about the topography, structure and function of the patella in marsupials. Therefore the stifles of 61 marsupials of 30 different species were studied by radiography, necropsy and light microscopy. It was found that only the family of bandicoots (Peramelidae) possessed a typical patella. The other species revealed a patelloid consisting of fibrocartilage. The structure of the patelloid revealed common characteristic features in the following families of marsupials: (1) Dasyuridae, Phalangeridae. Pseudocheriidae, and Potoroidae; (2) Burramyidae; (3) Phascolarctidae, Vombatidae, and Dendrolagus; and (4) Superfamily Macropodoidea (except Dendrolagus and Potoroidae). Our results imply that the degree of differentiation in the fibrocartilage of the patelloid was strongly correlated to the mechanical forces acting on the patelloid which are a result of the specific kind of locomotion and the way of life. Generally the bony patella does not belong to the phylogenetic programme of the marsupials--with the exception of the bandicoots which are very closely related to the subclass of placental mammals (Eutheria).

Pododermal angioarchitecture of the bovine claw in relation to form and function of the papillary body: a scanning electron microscopic study.

The region-specific angioarchitecture of the bovine pododerma was examined using systematic scanning electron microscopy of micro-corrosion casts of juvenile and adult bovine claws. Particular emphasis was laid on the demonstration of specialised vascular structures such as arteriovenous anastomoses. Comparing the results of main and dew claws, respectively, of juvenile and adult claws, a relation between burdening of the claw and density and differentiation of the pododermal papillary and lamellar blood vessels was detected. The results suggest a possible influence of body weight (or age) and weight-bearing on the formation and vascularisation of the pododermal papillary body. The lamellar and papillary microvascularisation and microcirculation are discussed.

On the development of the papillary body in the feline claw.

The pre- and post-natal development of the feline claw was studied in 22 feline fetuses with a crown-rump length (CRL) ranging from 40 to 160 mm, in six kittens up to an age of 22 days, and in four adult cats. In fetuses up to a CRL of 75 mm, the characteristic shape of the feline claw was developed. Segment-specific dermal modifications in the various segments, especially the dorsal ridge, started to develop in fetuses with a CRL between 75 and 105 mm. Modifications of the papillary body in the different claw segments took place in the last third of prenatal development and were continued postnatally. At first, the basal lamina became wavy, followed by the formation of small dermal microridges, which would be enlarged to dermal ridges and lamellae. In the claw of adult cats, the papillary body was very small. The dermal tissue of the proximal part of the coronet formed low microridges with short papillae originating on and between these low ridges. In the wall segment, dermal microridges were formed which were arranged in a parallel fashion, and in the distal part of the wall, short dermal micropapillae arose on the crest of each microridge. In the sole segment, thin dermal lamellae were developed. The sequence of papillary body development and the varying conformations of the papillary body in the different segments of the feline claw are compared to those in the nail, the canine claw and hooves.

Laminitis in Przewalski horses kept in a semireserve.

Semireserves were created by the European Conservation Project for scientific research in preparation for reintroduction in the wilderness. They are defined as enclosures large enough to carry a group of Przewalski horses throughout the year without any additional feeding. The semireserve offers diverse opportunities for significant scientific research. As part of a general screening program, the hoof development in a group of Przewalski horses was investigated in the semireserve Schorfheide near Berlin. Since the foundation of this semireserve in 1992, veterinary treatment was not necessary with the exception of hoof trimming in two animals in 1993. However, major health problems were encountered in the spring of 1999, when three other mares showed signs of laminitis. The initial diagnosis by the authors and the local veterinary surgeon based on observation of behaviour, gait, stance, walk and trot of three mares whose initial weights were higher than those of the healthy mares. The initial diagnosis was confirmed by palpation and the occurrence of very deep horn rings on all hooves and a laminitic horn ring on the right front hoof of one mare. An adequate laminitic therapy was not possible under the conditions of a semireserve. The applied management aimed at two goals: 1. To reduce endotoxin production and acidosis in the horses by reducing the ingestion of carbohydrate rich food. 2. To reduce the mares level of activity and to prevent tearing of the suspensory apparatus of the coffin bone. To achieve these two goals it was decided to remove the three laminitic mares from the rich pasture in the main part of the semireserve and to confine them onto the poorer pasture of the small separately fenced area. All three affected mares had fully recovered from their laminitic condition. Prevention of grass laminitis can be achieved by the following measures: 1. Reduction in grass intake could be achieved by increasing the grazing pressure by an increase in stocking rate of the horses or mixed grazing with another species such as sheep. 2. A longer term solution to the problem may well be to sow specific varieties of grass with lower concentrations of water soluble carbohydrate.

How structures in bovine hoof epidermis are influenced by nutritional factors.

The structure of the hoof epidermis is the link between nutrition and horn quality. The aim of this study was to demonstrate the relationship of single structures in the process of keratinization and cornification of bovine hoof epidermis to certain nutritional factors such as lipids, minerals and vitamins. Furthermore, we wanted to show the structural changes in the dyskeratotic epidermis caused by an insufficient supply of keratinizing epidermal cells. For our study we used samples of hoof epidermis from 25 dual-purpose dairy cattle, with ages ranging between 2.5 and 4 years. We also obtained a complete set of hooves from a biotin-deficient calf. All samples were investigated by light and transmission electron microscopy, using routine methods as well as histochemical and enzyme-histochemical techniques. We focused on epidermal structures that have a major influence on horn quality and are known to be related to single nutritional factors. The strength of the keratin filament bundles is determined by their cross-linking via sulphur-containing amino acids. Essential fatty acids are required for the synthesis of an intercellular cementing substance connecting the horn cells and establishing a permeability barrier in the stratum corneum. Minerals, in particular calcium, are essential for activation of enzymes that are a prerequisite for physiological keratinization and cornification. Furthermore, vitamins such as biotin are essential in the metabolism of the keratinizing epidermal cells.

Fetal development of the white line (Zona alba) of the equine hoof.

The fetal development of the white line (Zona alba) in the equine hoof is described. Its specific structure of lamellar and interlamellar horn, which in turn is composed of cap and terminal horn, is formed in the second half of the hoof's fetal development. In equine fetuses with a crown-rump length of less than 550 mm, the hoof capsule lacks a 'characteristic' white line since no borders between stratum medium, stratum internum and sole horn are discernible. In the hoof of an equine fetus with a crown-rump length of 550 mm, a narrow white line has taken shape. Its shallow lamellae are arranged like arcades. Between the horn lamellae lie the polyhedral cells of the interlamellar horn. Up until birth, the height of the horn lamellae and, therefore, the width of the white line increases significantly. In the white line of the hoof of newborn foals, the terminal horn contains horn tubules with a characteristic architecture.

Subsurface crypts and interstitial cells in the ovary of the seal (Phoca vitulina vitulina): light and electron microscopic findings.

This morphological study on the ovary of the seal focuses on two structures of special interest: the subsurface crypts and the interstitial cells. Ovaries from 110 seals (from 1,5 months to 12 years) were used. Most of the seals of our study originated from German North Coast, a few from Island. The ovaries were examined by light microscopic as well as by transmission and scanning electron microscopic techniques. The seal's ovary conforms to the basic structure of the ovary of other mammalian species. However, the surface epithelium cell layer lowers itself into an epithelium lined - broadly branching system of subsurface crypts. The size and extent of these crypts and the proliferation of the epithelium appear to be mainly related to the reproductive activity. The ultrastructure of crypt epithelium cells indicates a remarkable metabolic activity. In juvenile ovaries cell buds proliferate from the crypt epithelium and grow as plug-like strands into the cortical stroma. These cells show ultrastructural changes during their proliferation and appear to transform into steroid producing interstitial cells. In the adult seal the interstitial cells are completely differentiated established and, according to their origin, can be divided into epithelial and fibroblastic interstitial cells. It is suggested that a major function of the crypts is the formation of the ovarian blastema with particular reference to ovarian interstitial cells. The intensive proliferation of interstitial cells is in agreement with the extraordinary high level of 350 pmol estrogen/l blood serum.

Rate of keratinization of the wall segment of the hoof and its relation to width and structure of the zona alba (white line) with respect to claw disease in cattle.

OBJECTIVES: To determine contribution of the wall segment of bovine cattle hoof to horn production, and relevance of structural differences of the wall segment and its horn production rate to claw disease. DESIGN: Epidermis and papillary body of the wall segment were examined by mesoscopy, light microscopy, and transmission and scanning electron microscopy. Morphometry of the entire length of the zona alba was examined, and the horn production rate of the wall segment was calculated. ANIMALS: Mixed-breed, dual purpose (beef and dairy) cattle of either sex, and young (20 months) Holstein-Friesian beef bulls. PROCEDURE: Blocks of a strip of the hoof from the coronary segment to the sole margin, including epidermis and dermis, were prepared for light and transmission electon microscopy. Prepared specimens of the wall-sole border were examined by scanning electron microscopy. Morphometry was performed on the outer, middle, and inner parts of the zona alba structures on unfixed horn specimens of beef bull claws. After removal of the zona alba specimens, the claw was removed and the proximodistal extent of the epidermal leaflets was measured and analyzed statistically. RESULTS: Horn production increased in the distal half of the wall segment, was greatest at the wall-sole border, and highest above the abaxial end of the zona alba. High horn production resulted in an incompletely keratinized, softer horn. CONCLUSIONS AND CLINICAL RELEVANCE: High horn production at the zona alba increases susceptibility to vascular disturbance. Claw dyskeratoses appear first in areas of high horn production, areas which are also subject to a greater frequency of claw lesions.

[Structural factors influencing the horn quality and predilection sites for diseases at the bottom surface of the bovine hoof]. / Strukturelle Faktoren mit Einfluss auf die Hornqualität und Prädilektionsstellen für Erkrankungen an der Fussungsfläche der Rinderklaue.

The quality of the horn of the cattle hoof varies in the different segments of the ground surface adapted to weight bearing. Horn quality is influenced by the following main factors: the keratin proteins as the most important intracellular factor, the intercellular cementing substance as the intercellular factor, and the architecture of the cluster of horn cells, i.e. the arrangement of horn cells in tubular and intertubular horn. Differences in the structure and composition of these factors and their respective combination determine the different degrees of hardness of hoof horn, which are even palpable. In special places, as i.e. the white zone, the combination of all these above-mentioned factors determines sites of predilection for diseases of the cattle hoof like white line disease.

The topography of the lymph heart in the domestic chicken (Gallus domesticus).

Although at the time of hatching, the lymph heart of the domestic chicken (Gallus domesticus) is usually considered to have atrophied, our findings suggest otherwise. Apart from the lymphatic-venous (L-V) anastomoses between the thoracoabdominal lymph trunks and the superior vena cava in the chest, there are two other L-V anastomoses in the sacral region. These L-V communications connect the lymph heart with three inter-segmental veins and with the L-V sinus of the dura mater. The topography of the lymph heart was demonstrated using direct and indirect blue dye injections depending on the age of the chicken. Lymphatic continuity was noted up to the 15th week of age from lymphatics of the hindlimb into the lymph heart via the thoracoabdominal lymph trunk, including communications of the lymph heart with the venous system and dural sinus. At 16 weeks of age, lymph flow apparently ceases caudally, but continues superiorly into the venous system. In the egg, the lymph heart may help propel interstitial fluid in the motionless fetus. After hatching, the lymph heart may facilitate fluid propulsion through L-V communications in the spinal canal.

[Prenatal development of the horse ovary]. / Zur praenatalen Entwicklung des Pferdeovars.

To answer the many open questions concerning the development of the horse's ovary, first the prenatal development was investigated. It resulted that follicles derive from the germinal epithelium and its cords, whereas the Leydig cells and the rete blastema originate from the mesonephros. In the second third of pregnancy the Leydig cells undergo an enormous proliferation, in the last third they degenerate. However this degeneration is not connected with the postnatal development of the ovulation groove.

[The segmental organization and horny structure of the claw of the dog]. / Die segmentale Gliederung und Hornstruktur an der Kralle des Hundes.

This study classifies the segments of the dog claw and presents a new conception to define crown and wall segments that deviates from the common statements in literature. The perioplic segment extends along the internal surface of the claw fold (vallum). The crown segment lies in the unguicular groove, and there in a semicircular zone. In the crown segment there is development of horn tubuli, but these lose their tubular structure before they have reached the top of the claw. The wall segment, adjacent distally, comprises a dorsal ridge, and lateral surfaces proximally and distally which are all marked by superficial lamellar-shaped surface configurations. The sole segment shows desquamative soft horn and is situated between the free margin of the wall segment palmar/plantar to the unguicular process. The new conception of homology of dog claw distinguishes between main and secondary criteria. The main criterion is the epidermal and dermal configuration. Secondary criteria are the typical horn products (for example perioplic horn) and dimension, shape and topography of segments. The sterile/fertile-bed theory, which was believed to be the determining factor for the classification of the dog claw, is neither the proper method to define the individual segments nor to judge the rate of cornification.

Anatomy of the prepubic tendon in the horse, cow, sheep, goat, and dog.

Analyses of the fibers in the prepubic tendon of the horse and ruminants have shown that it is composed of the crossed and uncrossed tendons of origin of the pectineus muscles, the pelvic tendons of the rectus and obliquus abdominis muscles, and the tendons of origin of the cranial parts of the gracilis muscles. Pelvic attachments of the linea alba and the yellow abdominal tunic are incorporated in it. It is not a transverse ligament, and it is not homologous to the human superior (cranial) pubic ligament. The dog differs in 4 respects: (1) the pectineus tendons do not cross, but each originates from the pubic bone of the same side; (2) an iliopubic cartilage is intercalated in the prepubic tendon on each side at the junction of the pectineus tendon and the abdominal and pelvic tendons of the external oblique at the caudal angle of the superficial inguinal ring; (3) in some dogs, the caudal border of the aponeurosis of the transversus abdominis joins the prepubic tendon; (4) the gracilis tendon does not extend to the prepubic tendon. The clinical anatomy was described, illustrated, and compared between species. Conflicting descriptions in the literature were discussed and resolved by new approaches to the dissection. Studies of the inguinal region in the cat and pig were reviewed. A table of nomenclature is included.

[A lectin histochemical study of the epidermis off the skin and the hoof of horses]. / Eine lectinhistochemische Untersuchung der Epidermis von Haut und Huf des Pferdes.

Carbohydrate moieties of cell membranes in the epidermis of equine skin and hoof were investigated using lectin-histochemistry. The loss of desmosomes during keratinization leads to a reduced lectin affinity. Lectin binding capacity of the intercellular matrix in the stratum corneum of the epidermis is weak compared to that of the intercellular kitt of the hoof. Qualitative differences in lectin binding of the intercellular kitt of different hoof segments correlate with the quality of the horn in the respective areas.