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.

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.

The bursa cloacae (Fabricii) of Struthioniforms in comparison with the bursa of other birds.

The late embryonic and postembryonic genesis of the bursa cloacae (Fabricii) of struthioniforms and other birds is described and discussed. The bursa of ostrich and emu is a wall organ of the caudal cloacal chamber. The bursa of rhea is, like the bursa of Gallus, a cranial appendix of the proctodeum. Lobuli bursales of struthioniforms are composed of a peripheral pars lymphoepithelialis (PLE) and a central pars lymphoreticularis (PLR). By contrast, lobuli bursales of Gallus are composed of a peripheral PLR and a central PLE. The fine structure of the bursa of struthioniforms is described. Other than in Gallus, the apical cell association of the PLE of struthioniforms shows secretory granules. This study thus far does not answer in detail the question of how the imprinting mechanism of the B-lymphocytes operates. It is assumed that they are imprinted in the PLE. Postcapillary venules in the PLR are responsible for the transport of B-lymphocytes. Hormonal bursectomies have been made to get information about the involution of the bursa of struthioniforms. In these species, involution means a gradual metaplasia while in Gallus it means a complete degeneration of the bursa.

Lymph heart musculature in birds.

Development and innervation of the lymph heart musculature of chicken, emu, rhea, and duck was studied by electron microscopy at post-hatch ages from 3 days to adulthood. Development of innervation was monitored by acetylcholinesterase staining. Horseradish peroxidase was used to determine the extent of the transverse tubule network. Chickens were unusual among these birds in that lymph heart myocytes had already undergone a definitive differentiation and degeneration by 3 days. In ducks and ratite birds, lymph heart myocytes more slowly but progressively differentiate a cytomorphology that does not conform in all characteristics to cardiac or skeletal muscle and even resembles in some aspects, smooth muscle. Myofibrils become the dominant cytoplasmic structure, transverse tubules form "internal couplings" with agranular reticulum cisternae, and "external couplings" are formed between myocytes at myomyal junctions. The myomyal junctions also contain AChE-positive reaction product and some subplasmalemmal vesicles that lack a dense core. The lymph heart myocardium of ducks of 2 weeks demonstrated mitotic figures. In adult ducks the myosatellite cell numbers diminish and a characteristic pattern of myocyte degeneration appears. In juvenile ducks and ratites some myocytes differentiate to conductile cells, much as the conductile myocytes and myofibers of the blood heart. The lymph heart innervation is described, and the role of nerve in differentiation and maintenance of myocyte morphology in the lymph heart is discussed.

The epididymis and its development in ratite birds (ostrich, emu, rhea).

The epididymis of ratitae is subdivided into a main part and a appendix epididymidis. The appendix epididymidis consists of the ductus aberrans and ductuli aberrantes. The ductus aberrans is the cranial continuation of the ductus epididymidis. The appendix epididymidis is cranially attached to the adrenal gland. In the main part of the epididymis the largest part of the rete testis is found. The rete testis is composed of an intratesticular rete (also named tubuli recti), and intracapsular rete (with a longitudinal cistern and a true rete), and an extratesticular rete (predominantly consisting of approximately 20 longitudinal channels). The rete testis develops most likely embryonally from buds of the glomerular capsules of the mesonephros. The ductuli efferentes proximales also from these capsules, while the ductuli efferentes distales develop from the proximal and distal tubules and intermediate-segments of the mesonephros. The ductus epididymidis originates from the Wolffian duct and meanders dorsolaterally through the epididymis.

Morphology of the epididymis of the cock (Gallus domesticus) and its effect upon the steroid sex hormone synthesis. I. Ontogenesis, morphology and distribution of the epididymis.

The epididymis of the cock is divided into a main part and an appendix epididymidis. The main part of the epididymis is firmly connected to the testis. The sperm transporting tubes open into the ductus epididymidis along its entire length. The rete testis, as the most proximal part of the epididymis, develops from mesenchym cells. The rete testis connects the tubuli seminiferi with the ductuli efferentes proximales which develop from the Bowman's capsules of the mesonephros. The ductuli efferentes distales develop from the proximal tubules, conducting segments (loops of Henle), and the distal tubules of the mesonephros. The short ductuli conjugentes which open into the ductus epididymidis, originate from the connecting segments of the mesonephros. In the sexually mature cock the rete testis, the ductuli efferentes proximales, and the ductus epididymidis all show an enlargement in the lumen. In the ductuli efferentes proximales and in the ductus epididymidis one can observe a formation of globuli and cell protrusion which lead to a loss of the surface structure of the epithelial cells. The appendix epididymidis and the capsula fibrosa of the adrenal gland are joined by connective tissue. The appendix epididymidis consists of the blindly ending ductus aberrans (the crainal continuation of the ductus epididymidis) and the ductuli aberrantes which open into the ductus aberrans. The blind ends of the ductuli aberrantes end in the capsula fibrosa of the adrenal gland.

Morphology of the epididymis of the cock (Gallus domesticus) and its effect upon the steroid sex hormone synthesis. II. Steroid sex hormone synthesis in the tubuli epididymidis and the transformation of the ductuli aberrantes into hormone producing noduli epididymidis in the capsule of the adrenal gland of the capon.

Distinct histochemical and ultrastructural signs of a steroid hormone synthesis are found in the sexually mature cock, particularly in the ductuli efferentes proximales of the main part of the epididymis and in the blind ends of the ductuli aberrantes of the appendix epididymidis. These signs are more distinct in the appendix epididymidis of the capon since the blind ends of the ductuli aberrantes transform into steroid sex hormone producing noduli epididymidis after they sprout out intensively and branch inside or beneath the adrenal capsule. The signs of virility were lost immediately after castration. They become more distinct again due to the hormonal activity of the noduli. Due to the morphologic agreement the noduli epididymidis of the capon are homologous to the noduli epoophori of the hen.

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.

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.

TEM and SEM investigations of lymph hearts in birds.

The fine structure of lymph hearts in birds is described. These organs could be made visible by application of marker medium and indirect and direct injection of contrast medium. As two special morphologic features we note strange modified skeletal muscle cells in the wall of the lymph hearts and efferent collectors to the epidural spinal lymphovenous sinus. The lymph hearts possess valves that regulate the passage of lymph from the lymphatic copulatory organ and the thoracic duct into the venous blood system.

Microstructure of fermented sausage.

A protein matrix is necessary for the desired texture of fermented sausages suitable for slicing. The formation of this network is predominantly induced by myosin and actin proteins. A change in the structure of native muscle proteins results from different technological processes such as chopping, salting, and fermentation. During chopping with simultaneous release of meat proteins, the salt brings about a change in the original structure of proteins by swelling and partial solution of myofibrils. The dissolved proteins are transformed into a thin fluid colloidal transition state, the so-called 'sol-state' with unstable coagulation bonds. During sausage ripening, as a result of denaturation by lactic-acid and due to gradual loss of water (drying), the unstable bonds are replaced by condensation bonds, and thus the sol-state is converted into the 'gel-state'. Both gel formation (condensation structure) and water evaporation (syneresis) result in the development of a matrix in fermented sausage and, consequently, in the texture of the sliceable product.

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.

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.

Light and electron microscopy of keratinization in the laminar epidermis of the equine hoof with reference to laminitis.

The laminar epidermis (epidermis parietis) of hooves from 14 clinically normal horses, 6 months to 15 years old, was examined by light and electron microscopy and immunofluorescence to measure the contributions of this region to the formation of the hoof wall. By their progressive keratinization to form primary epidermal laminae, the secondary epidermal laminae ultimately contributed about 20% of the thickness of the hoof wall (as revealed in the white line [zona alba]). The keratinized, primary epidermal laminae were developed to a height of 4 mm during their proximodistal-course, much of this obscured because of their basal portion being embedded in the cap horn epidermis. From evaluation of structural changes accompanying keratinogenesis in the cell and determination of the contribution of the laminar epidermis to the formation of laminar horn, cap horn, connecting horn, terminal horn, and the white line, we concluded that the sterile bed concept of a nongerminative role for the secondary epidermal laminae is no longer tenable.

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.

[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.

[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.

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.

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.