排序方式： 共有55条查询结果，搜索用时 15 毫秒
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S. Buda D. Grnemeyer H. M. Hafez M. Matzke A. Walter K. D. Budras 《Anatomia, histologia, embryologia》2005,34(Z1):9-9
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. 相似文献
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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. 相似文献
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Ch. K. W. M . ülling H. H. Bragulla S. Reese K. -D. Budras W. Steinberg 《Anatomia, histologia, embryologia》1999,28(2):103-108
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. 相似文献
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The early development of the gonads, and the ontogenesis of the rete testis and tubuli seminiferi recti in the chicken (Gallus domesticus) The primordium of the gonads can be discerned in the 4-day chick embryo by the elevation of the celomic epithelium to form germinal epithelium, and by the arrival of the primordial germ cells. Already in the 4½ day chick embryo there appears on the left side of the body, as a result of the first proliferation of the germinal epithelium, a subepithelial mesenchymelike cell conglomeration, which has been erroneously labelled in the literature a “urogenital union”. In contrast to the opinion expressed in the literature such a union does not appear until the 10th day, when the mesenchymal cells change to forerunners of rete cells which after hatching differentiate into rete-epithelial cells. The rete testis consists of intra and extratesticular transverse cisterns and of an intercalated and partically subdivided longitudinal cistern. The tubuli seminiferi contori end on the intracapsular lingitudinal cisterns either directly, or indirectly by intercalated tubuli siminiferi recti or intratesticular transverse cisterns. 相似文献
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BACKGROUND: The susceptibility of adult house cricket, Acheta domesticus (L.), adult convergent lady beetle, Hippodamia convergens (Guérin‐Méneville), and larval fall armyworm, Spodoptera frugiperda (JE Smith), to resmethrin and δ‐phenothrin synergized with piperonyl butoxide (PBO) was evaluated in a laboratory bioassay procedure. RESULTS: The 1 day LC50 values for resmethrin + PBO were 23.2, 32.08 and 307.18 ng cm?2 for A. domesticus, H. convergens and S. frugiperda respectively. The 1 day LC50 values for δ‐phenothrin + PBO were 26.9, 74.91 and 228.57 ng cm?2 for A. domesticus, H. convergens and S. frugiperda respectively. The regression relationship between species mortality and concentration explained 51–81% of the variation for resmethrin + PBO and 72–97% of the variation for δ‐phenothrin + PBO. The LC50 values decreased with time for these insecticides for all surrogate species. In terms of sensitivities among the insects to resmethrin + PBO and δ‐phenothrin + PBO, A. domesticus was most sensitive, followed by H. convergens and then S. frugiperda. CONCLUSION: The results indicate that resmethrin + PBO was generally more toxic than δ‐phenothrin + PBO. Based on the results, A. domesticus seems to be a good surrogate species for estimating potential non‐target terrestrial insect impacts from exposure to pyrethroids used in public health applications. Copyright © 2008 Society of Chemical Industry 相似文献
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Lymph system and lymphatic drainage in the testis of the Peking drake ( Anas platyrhynchos , L.)
After perfusion fixation the lymph vascular system can be distinguished sharply from the blood vascular system because the formation of lymph proteins is a reliable distinguishing criterion. Prelymphatic spaces without endothelial lining among seminiferous tubules partially communicate with lymph capillaries that are continuous with lymph sinusoids. Lymphatic vessels whose walls as yet contain no muscle are already present between the seminiferous tubules. The lymph then flows to the tunica albuginea in which it was possible to demonstrate, by injection of Prussian Blue, an narrow-mesh lymphatic network. Collecting vessels converge on the hilus and carry the lymph to the thoracoabdominal trunk. Right and left trunks, singly or after joining, enter the blood vascular system close to the left angle of veins. 相似文献
After perfusion fixation the lymph vascular system can be distinguished sharply from the blood vascular system because the formation of lymph proteins is a reliable distinguishing criterion. Prelymphatic spaces without endothelial lining among seminiferous tubules partially communicate with lymph capillaries that are continuous with lymph sinusoids. Lymphatic vessels whose walls as yet contain no muscle are already present between the seminiferous tubules. The lymph then flows to the tunica albuginea in which it was possible to demonstrate, by injection of Prussian Blue, an narrow-mesh lymphatic network. Collecting vessels converge on the hilus and carry the lymph to the thoracoabdominal trunk. Right and left trunks, singly or after joining, enter the blood vascular system close to the left angle of veins. 相似文献