Bibliothek

Notizen: Electronmicroscopical studies of transudation between blood capillaries and lymph capillaries in the lymphobulbus of the phallus of the cockerel (Gallus domesticus)The blood capillaries of the lymphobulbus cloacae may be divided into circulatory and transudation capillaries and may be distinguished from one another and from the lymph capillaries by ten criteria. The specific structure of the wall of these capillaries permits transudation of lymph from the blood-vascular to the lymphatic system. The lymph passes through the pores and fenestrae of the transudation capillaries into the interstitium and from here by two routes into the lymphobulbus. One route is intracellular-vesicular, and the other is intercellular (between the endothelial cells of the lymph capillaries). The contraction of the striated M. sphincter cloacae during erection of the phallus presses the lymph through the ductus lymphaticus bulbospongiosus cloacae into the corpus cavernosum of the phallus. There is a relationship between the structure and functional stages of the lymphobulbus and age, and between the former and the levels of the steroid sex hormones.

Notizen: Introduction:  The pathomechanisms of bovine laminitis are still poorly understood. Isolated perfused organ models are promising tools to study the biological mechanisms that lie behind diseases. They are preferable for ethical and financial reasons but also for experimental necessities.Aims:  To develop an isolated haemoperfused distal cow limb model, basing on an already existing porcine limb model used in experiments studying the effects of bioactive molecules.Methods:  Isolated limbs and blood were obtained from routinely slaughtered cows and subsequently perfused in the laboratory of a biotech company (Vitro-Tec, Berlin) with expertise in organ perfusion. A standard perfusion apparatus enables perfusion for up to six hours under close to physiological conditions. Perfusion pressure and flow were calculated based on values available for horses and pigs. The oxygen saturation was kept at 100% and the pH between 7.35 and 7.45. Glucose was added as nutrient. The lactate concentration was measured as a parameter for oxygen supply and free haemoglobin as an indicator for haemolysis. Potassium content and pressure served as vitality indicators. Additionally, morphological criteria of tissue integrity were assessed using light and electron microscopy.Results:  A constant flow of 150–200 ml/min was optimal. The resulting pressure ranged from 30 to 117 mmHg. Light microscopy revealed, with exception of a few thromboses, no cellular damage after 4 h. The perfusion was successfully extended to 5 h. Then first pressure related alterations including vascular dilatations and cellular degeneration occurred in the dermal lamellae but not in the other regions. Potassium never exceeded physiological values.Conclusion:  The model is now available for experiments. Equipment and technical implementation have been standardized and described in a standard operating procedure. The model will be challenged by bioactive molecules such as lactate, neuropeptides and chemokines. Ischaemic conditions will be simulated and studied.This work was supported by the European Communities under the Lame Cow Project QLK5-CT-2002-00969.The authors are solely responsible and the work does not necessarily represent the opinion of the European Communities.

Notizen: Introduction:  Most of the morphological studies on the skin of birds refer to chickens. Little can be found about the specific fine structure of the foot-pad epidermis of turkeys and almost nothing is known about the developing reticulate scales in turkey foetuses. This study deals with the question as to whether the development and morphology of the reticulate scales of turkeys are similar to those of chickens. Since the first signs of food-pad dermatitis can be observed in turkey poults at the age of four days, it was additionally examined if these alterations can be found in turkey foetuses already.Methods:  Foot pad samples of heavy strain BUT Big 6 turkeys were collected at different developmental stages (day 20, 23, and 28 of incubation). The specimens were compared by light- and electron-microscopic methods.Results:  On the 20th day of incubation, the reticulate scales cover the food pads as small knob-like structures. Between the embryonic epidermal cells wide inter-cellular spaces are visible, and in the intermediate cells multigranular bodies (MGBs) are detectable. Peridermal cells cover the reticulate scales. They are characterized by peridermal granules and protuberances of the outer cell membrane. On the 23rd day of incubation, many lipid droplets are scattered within the intermediate cells. Because a thin stratum corneum has formed, the periderm is almost completely sloughing off. On the 28th day of incubation, the turkey poults hatch. The epidermis has almost reached maturity and a broad stratum corneum is detectable.Conclusions:  The development and morphology of the reticulate scale epidermis of turkey is comparable to that of chicken, although little differences were found. Besides former investigations, which described the peridermal protuberances as microvilli, scanning-electron microscopy proved that they also show a fingerprint-like surface structure that has not been observed for birds previously. Up to the hatching day, no signs of food pad alterations are seen in developing turkeys.

Notizen: Gap junction mediated inter-cellular communication plays a crucial role in maintaining tissue homeostasis in skin. Gap junctions consist of hemi-channels (connexons), which in turn are established by transmembrane proteins (connexins, Cx). The pattern of Cx- protein expression is characteristic for tissues and depends on the differentiational and functional state.Aim:  As part of our investigations of cell biological causes for lameness in dairy cows we wanted to assess the expression of Cx-proteins in relation to differentiation in bovine claw epidermis.Methods:  We examined hoof tissue from five defined regions of the claws of 10 cows from the abattoir by immunohistochemistry, Western blot and by transmission electron microscopy. The following monoclonal antibodies were used: anti- Cx26, Cx31, Cx37 (ADI, USA) and anti-Cx43 (Chemicon, USA). Immunohistochemistry was carried out on frozen and paraffin sections.Results:  Cx43 was expressed in the bovine claw epidermis in a pattern described for skin. Cx43 expression was strongest in the stratum basale in all regions. Cells of the stratum spinosum expressed lower levels, and in terminal differentiating cells Cx43 was disappearing. Expression of Cx26, 31 and 37 showed a high variation between individuals and regions. Protein expression was verified by Western blotting. The formation of gap junctions in the respective layers was confirmed by electron microscopy.Conclusion:  Our results provide evidence that Cx 43 is expressed in bovine claw epidermis in a distribution similar to skin. Cx 43 is progressively downregulated with the progress of differentiation. This suggests a role of Cx43 in cellular coordination particularly in the early stages of differentiation. Results for Cx 26, 31 and 37 will be confirmed in further studies also on the mRNA level to get deeper insight in the regulation of Cx expression in claw epidermis. We hypothesize that Cx 43 plays a similar role in controlling differentiation as in skin and may be involved in disruption of claw horn formation in claw disorders.Acknowledgement:  This work was supported by the European Communities under the Lamecow project QLK5-CT-2002-00969. The authors are solely responsible and the work does not necessarily represent the opinion of the European Communities.

Notizen: The aim of this study was to establish a co-culture of bovine hoof keratinocytes and fibroblasts in different types of perfusion chambers under defined conditions. The perfusion chamber PCS3c (Oligene, Berlin) was used to culture dermal fibroblasts and epidermal keratinocytes separated by a Millicell® Insert (Millipore, Schwalbach). In addition novel perfusion chambers developed by Dirk Hoffmann were used in combination with S & S membrane filters (Schleicher & Schuell, Dassel). First, fibroblasts were seeded onto one side of the insert/membrane and allowed to grow for 4 days. Subsequently keratinocytes were seeded onto the other side and allowed to adhere for one day. Then the chambers were connected to the tubing system with an attached 8-channel pump and a gas permeable media bag. We worked with different media and flow rates ranging from 0.035 ml/min to 0.35 ml/min. The system was run for up to 20 days. After a few days in culture the cells had grown to confluence. Then keratinocytes began to differentiate and built up stratified colonies. Within these colonies the cells showed the characteristic morphology of a stratified squamous epithelium. The use of perfusion chambers allows three-dimensional cultures to grow and survive for weeks, because of an unlimited medium supply and gas exchange. Additional, perfusion chamber systems enable the co-cultivation of fibroblasts and keratinocytes separated by membranes, which permit the exchange of molecules like growth factors. Furthermore, it is possible to perfuse the two different parts of the perfusion chamber with various and even different types of media. This provides the opportunity to add a growth factor to the medium for only one cell type and to study the effect of this factor to the other cell type. This work was supported by the European Communities under the Lamecow project QLK5-CT-2002-00969.The authors are solely responsible and the work does not necessarily represent the opinion of the European Communities.

Notizen: Im Gegensatz zu derzeitiger Auffassung wird nachgewiesen, daß der M. cremaster ext. resp. compressor mammae des Hundes ein Abkömmling des M. transversus abdominis und nicht des M. obliquus int. abdominis ist. Vergleichend-anatomisch besitzt er zwar gelegentlich auch einen schwachen Internuskopf, der Transversuskopf aber überwiegt bei weitem.〈section xml:id="abs1-2"〉〈title type="main"〉SummaryThe M. cremaster externus (M. compressor mammae in the bitch) of the dogContrary to the present concept that the M. cremaster ext. (M. compressor mammae in the bitch) is derived from the M. obliquus internus abdominis, evidence is presented that it is derived from the M. transversus abdominis. Comparatively speaking, the cremaster does occasionally present a part derived from the internus, but the part derived from the transversus is by far the larger.〈section xml:id="abs1-3"〉〈title type="main"〉RésuméLe muscle crémaster externe, resp. muscle compresseur de la mamelle du chienA l'encontre de la conception actuelle, on montre que le muscle crémaster externe, resp. muscle compresseur de la mamelle du chien, est un dérivé du muscle transverse de l'abdomen et non du muscle petit oblique de l'abdomen. Du point de vue de l'anatomie comparée, il peut aussi présenter occasionnelle-ment un chef interne faible, mais c'est le chef transverse qui est de loin le plus important.〈section xml:id="abs1-4"〉〈title type="main"〉ResumenEl m. cremáster externo en el perro y el m. compresor de la mama en la perraEn contraposición a la interpretación actual, se demuestra que el m. cremáster externo del perro, resp. el m. compresor de la mama en la perra es un derivado del m. transverso abdominal y no del m. oblicuo interno abdominal. Aunque anatomico-comparativamente también posee en ocasiones una cabeza interna discreta, la cabeza transversa predomina en mucho.

Notizen: Introduction:  Leg weakness causes high economic losses in commercial poultry. The unspecific term includes, amongst others, diseases of the skeletal system caused by genetic, nutritional or microbiological factors. The analysis of computed tomography images may be a new tool to discriminate and evaluate skeletal abnormalities in turkeys and can therefore provide valuable hints in the treatment of turkey stocks suffering from leg weakness.Material and Methods:  Legs of healthy turkeys and those showing clinical signs of leg weakness were examined using a Tomoscan M/EG/Compact (Philips Medical Systems) CT system. The slice thickness and distance were set to 2 mm. In addition to the evaluation of the obtained images, the software system 3D-Doctor was used to create three-dimensional objects of the investigated samples.Results:  Differences between physiological and abnormal parts of the leg bones are distinguishable in the CT-images and three-dimensional reconstructed objects. Bone density can be calculated and thus provides a base to estimate possible nutritional demands or deficiencies. The three-dimensional reconstruction compensates for the difficulties in understanding the detailed anatomical CT cross-sections by which the examiner is confronted while studying the CT images.Conclusion:  Although computed tomography of poultry is too expensive for routine herd diagnosis, and far less for single-animal diagnosis, it is a valuable tool for investigating skeletal abnormalities and is very useful in examining samples related to leg weakness.

Notizen: Introduction:  Interactions between horn quality and flooring systems significantly impact on claw health. Poor horn quality is associated with reduced milk yield, painful lesions or slaughtering. Horn quality is determined by horn cells, intercellular cement and hoof horn architecture, i.e. the structure and arrangement of the horn tubules. Soft and elastic flooring systems have been reported to have a positive influence on the microstructure of hoof horn.Aims:  We wanted to correlate the microstructure of claw horn to the horn quality in a large number of samples and detect influences of the flooring system on hoof horn microstructure.Methods:  Samples were obtained from two different studies: 40 cows from Hohenheim/Germany kept on slatted floor and subsequently on rubber mats for 4 months; 1000 cows from 11 farms in Luxembourg, kept on concrete floor. From all samples 7 μm-sections were cut and stained with the PAS-reaction. Morphometry was done with the LuciaG©-software (Nikon GmbH, Düsseldorf, Germany) and statistical analysis was performed with SPSS® (SPSS Inc., Chicago, IL, USA). Parameters measured were area, minimal and maximal diameter of both medulla and cortex of horn tubules. Statistical analysis included: tubules per visual field, area per visual field, total medulla area, total cortex area and the limiting values of diameters.Results:  Luxembourg samples showed consistency of tubule-parameters between both dates; all farms showed an average number ranging from 13.36 to 14.79 tubules per visual field. Hohenheim horn from the hard flooring showed 19.9 and horn of the same animals kept on rubber floor showed 20.5 tubules per visual field. Maximum diameter of hard-floor horn is 55 μm whereas 45 μm in animals kept on rubber floor.Conclusions:  The results show that genetic/individual differences take smaller influence on horn quality than housing systems. These outcomes provide evidence for the economical and animal welfare benefit of soft and elastic flooring systems. Further research will focus on correlation of biodata, such as physiological state, lactation, age, and claw horn microstructure.This work was supported by Biopsytec/Rheinbach.

Notizen: Bei Untersuchung von Hilus-, Mark- und Rinden-Zwischenzellen im Hühnerovar ergibt sich, daß die Zellen des Marks durch Wachstumsvorgänge im Ovar restlos zu Rindenzellen werden. Alle Zellorganellen mit Ausnahme der Ergastoplasmazisternen und der Ribosomen nehmen nach Zahl und Größe vom embryonalen Alter bis zur Zeit höchster Eierstocksaktivität zu. Damit ist eine stetig zunehmende Syntheserate von Steroidhormonen verbunden. Bei der Glucke und in der Mauser tritt eine Verdrängung der Zellorganellen durdi Lipoidtropfen ein, was mit einer Verminderung der Steroidsynthese einhergeht.〈section xml:id="abs1-2"〉〈title type="main"〉SummaryThe mature interstitial cells in the hen's ovary and their topographical and ultrastructural-functional changesIf one differenciates Hilus-, Medullar-, and Cortex-Interstitial cells in the hen's ovary, it can be shown that all the cells of the medulla become cortex cells by the way of growth procedures in the ovary. All cell organelles with exception of the cysternae of the ergastoplasm and the ribosomes increase in number and size from the Embryo until the time of highest activity of the ovary. Herewith connected is a steady increasing rate of synthesis of steroid hormones. In the clucking and moulting hen the cell organelles are displaced by lipoid droplets. Herewith connected is a diminuation of the synthesis of steroid hormones.〈section xml:id="abs1-3"〉〈title type="main"〉RésuméLes cellules interstitielles mûres dans l'ovaire de la Poule, leur évolution topographique et leurs changements fonctionnels ultrastructurauxSi l'on considère les cellules interstitielles du Hile de la Medulla et du Cortex dans l'ovaire de la Poule, on peut constater que toutes les cellules de la medulla deviennent corticales par le jeu des processus de croissance dans l'ovaire. Tous les organites cellulaires, à l'exception des citernes de l'ergastoplasme et des ribosomes, augmentent en nombre et taille depuis l'embryon jusqu'au moment de la plus intense activité ovarienne. Parallèlement, on observe un taux d'accroissement régulier de la synthèse des hormones stéroïdes. Au moment de la couvaison et de la mue, les organites cellulaires sont déplacés par des gouttelettes lipoïdes. Conjointement, la synthèse des hormones stéroïdes diminue.〈section xml:id="abs1-4"〉〈title type="main"〉ResumenLas células intersticiales maduras en ovarios de gallina y sus modificaciones topográficas y ultraestructural-funcionalesAl difernciar las células hiliares-, medulares- y córtico-intersticiales en el ovario de gallina, se puede descubrir que todas las células de la medula se tornan en células corticales mediante procesos de crecimiento en el ovario. Todas las organelas celulares con excepción de las cisternas ergastoplasmáticas y de los ribosomas aumentan en cantidad y tamaño desde la edad embrionaria hasta el tiempo de actividad ovárica máxima. A esto se halla ligada una tasa de síntesis de hormonas esteroideas, que va en aumento continuo. En la clueca y durante la muda surje el desalojamiento de las organelas celulares por gotas lipoideas, lo que está. ligado a la disminución de la síntesis de hormonas esteroideas.