Morphological structure and peripheral innervation of the lateral line system in the Siberian sturgeon (Acipenser baerii)

Light and scanning electron microscopy (SEM) were used to study the epidermal lateral line system of the Siberian sturgeon (Acipenser baerii Brandt, 1869). This system consists of mechanoreceptive neuromasts, ampullae and the electroreceptive organ. The neuromasts are located in 5 pairs of cephalic and 1 pair of trunk canals and superficially in the middle and posterior pit lines that lie dorsomedially along the top of the skull immediately adjacent to the otic ampullae field. Both canal neuromasts and pit organ superficial neuromasts have opposite polarized hair cells that are parallel along the axis of the canal and pit line, respectively. However, they differ in both size and shape and in the density and length of the hair bundles. The ampullae are confined on the head, adjacent to the neuromast lines. The morphological structure of the ampullae in the Siberian sturgeon is similar to the ampullae in elasmobranchs and other primitive fish. Nevertheless, it has a relatively large mucus-filled ampulla, and a shorter and narrower canal leading to a small opening to the outer epidermal surface. We also present new information concerning the peripheral innervation of lateral line receptors in sturgeons. The receptors of the lateral line system are innervated by 2 pairs of cranial nerves: anterior and posterior lateral line nerves. The peripheral processes of the anterior lateral line nerve form superficial ophthalmic, buccal, otic and anteroventral rami. The peripheral processes of the posterior lateral line nerve form middle, supratemporal and lateral rami.     

Exquisite structure of the lateral line system in eyeless cavefish Sinocyclocheilus tianlinensis contrast to eyed Sinocyclocheilus macrophthalmus (Cypriniformes: Cyprinidae)

In this study, the lateral line systems in Chinese cavefish eyeless Sinocyclocheilus tianlinensis and eyed Sinocyclocheilus macrophthalmus were investigated to reveal their morphological changes to survive in harsh environments. Compared with the eyed cavefish S. macrophthalmus (atypical), the lateral line system in the eyeless cavefish S. tianlinensis (typical) has certain features to adapt to the dark cave environments: the superficial lateral line system in the eyeless species possesses a higher number of superficial neuromasts and more hair cells within an individual neuromast, and the trunk lateral line canal system in S. tianlinensis exhibits larger canal pores, higher canal diameter and more pronounced constrictions. Fluid–structure interaction analysis suggested that the trunk lateral line canal system in the eyeless S. tianlinensis should be more sensitive than that in the eyed S. macrophthalmus. These morphological features of the lateral line system in the eyeless S. tianlinensis probably enhance the functioning of the lateral line system and compensate for the lack of eyes. The revelation of the form–function relationship in the cavefish lateral line system provides inspiration for the design of sensitive artificial flow sensors.     

A comparative ultrastructural study of the pecten oculi in adult,juvenile, and nestling yellow‐legged gulls,Larus michahellis (Naumann, 1840)

This study aimed at examining the histological structure of the pecten oculi in the adult yellow‐legged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillous‐like folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the blood‐retina barrier.     

Regional and Cyclic Variations in the Ultrastructural Features of Secretory Cells in the Oviductal Epithelium of the Chinese Meishan Pig

The Chinese Meishan pig is prolific breed and it is considered that this pig has a capacity with higher rates of embryonic survival. The oviductal secretory cells may affect the embryonic development and survival. The aim of the present study was to investigate the ultrastructural features of secretory cells in the various regions of the Chinese Meishan pig oviduct during the follicular and luteal phases of the oestrous cycle. In the ampullar secretory cells, numerous secretory granules with moderately electron-dense matrices were present in the supranuclear cytoplasm and exocytosis of secretory granules was observed. The number of secretory granules was dramatically reduced in the ampullar secretory cells in the luteal phase. During the follicular phase in the fimbrial epithelium, the secretory cells contained rough endoplasmic reticulum and Golgi apparatus, but most cells had few small granules. In the luteal phase, the secretory cells in the ampullar and fimbrial epithelia extended beyond the luminal border of the ciliated cells. In the isthmus, many granules were present in the cytoplasm of secretory cells throughout the oestrous cycle, but the number of secretory granules was reduced in the luteal phase. The cytomorphometric data revealed that the height of ciliated cells decreased substantially in the fimbriae and ampulla at the luteal phase, while that of non-ciliated cells was less affected. These results suggest that the drastic reduction of cell height of ciliated cells cause the extrusion of most secretory cells beyond the ciliated cells in the fimbriae and ampulla during the luteal phase. In summary, our ultrastructural observations of Chinese Meishan pig oviduct revealed marked cyclic changes in the ultrastructural features of secretory cells. In particular, the ultrastructural features and the numbers of secretory granules were distinctive for each particular segment. These findings should provide insight into the regional and cellular differences in functions of secretory cells of the Chinese Meishan pig oviduct.     

Morphological and ultrastructural study of carpal organ in adult female wild swine

The carpal organ of adult female wild swine is a sweat-type gland which secretes an odorous substance. The gland consists of 5-7 lobes, each made up of lobules with convoluted glandular tubules. The gland secretion is transported in large excretory canals which empty from 5 to 7 clearly visible pores. An ultrastructural examination showed that the glandular tubules are made up of single-layered epithelium with different types of cells. One type, with rather electron-dense cytoplasm, is secretory cells full of granular material which empties into the tubule lumen. A second cell type has a glycogen-rich, transparent cytoplasm. Its role appears to be secreting a watery, electrolyte-containing liquid. In the intermediate zone of the tubules, there is a third type of cell with transparent cytoplasm. Its ultrastructural characteristics seem to indicate that its function is to reabsorb the excess watery component. In the wall of the glandular tubules, outside the epithelium, there are myoepithelial cells which facilitate the movement of the secretions toward the collector canal.     

Simple method for the perfusion-fixation of adult bovine brain

It is widely accepted that the vascular perfusion of a tissue leads to its optimal fixation for ultrastructural examination, but the technique has been applied with little success in large animals such as cattle. This paper describes a simple and highly reproducible method for the perfusion-fixation of adult bovine brain. The carotid arteries are cannulated and the perfusate is introduced by means of a peristaltic pump. The inclusion of toluidine blue in the fixative makes it possible to assess the success of the technique, and prevents the costly and time-consuming processing of material which is suboptimally fixed. The method is potentially valuable for the examination of a wide range of neurological conditions in large domestic animals at an ultrastructural level in optimally fixed material.     

Cytologic observations of the bovine teat end

Cells infiltrating from the vasculature and histologic components of internal tissues of teats (mammary papilla) from noninfected udder quarters were studied, using light and electron microscopy. Morphometric analysis demonstrated a progressive increase in number of infiltrating cells from the distal teat cistern (sinus papillaris) to the junction of the Furstenberg's rosette (distal termination and convergence of mucosal folds lining the teat cistern) and the streak canal (ductus papillaris). Plasma cells contributed to cellular increases in subepithelial connective tissue and were the most prevalent infiltrating cell type. Plasma cells also penetrated the basal epithelial lining of the rosette area and occasionally migrated to the luminal surface near the squamocolumnar junction. Neutrophils and monocytes contributed to the increase in cells infiltrating the epithelial lining. Few infiltrating cells were observed in epithelium and underlying stroma of the streak canal. Cytologic comparison demonstrated a reduction in all cell types from lactating to involuting phases of lactation. Greater numbers of plasma cells, lymphocytes, and monocytes were observed in teat end tissues from quarters previously infected with Staphylococcus aureus.     

动物氨基酸转运载体的研究进展

氨基酸转运载体（AAT）是一类介导氨基酸从细胞外转运到细胞内的重要蛋白，也是一类能介导氨基酸相关的信号通路的重要营养物质感受分子，在机体的生长代谢、营养健康等方面具有重要作用。动物机体中存在多种类型的AAT，它们能感知机体内相关氨基酸水平的变化，介导细胞氨基酸感知信号通路——哺乳动物雷帕霉素靶蛋白复合体1（mTORC1）和一般性调控阻遏蛋白激酶2（GCN2）的激活，从而引起通路下游发挥作用。在不同组织细胞中，发挥主导作用的AAT存在差异，表明AAT具有组织特异性，同时，AAT也受多种因素的影响，比如动物机体本身、营养物质水平、激素水平等。作者主要从AAT的类型及转运机制、介导营养信号启动及对mTORC1通路和GCN通路的影响、在不同组织中的作用及AAT表达的调控4个方面进行综述，从宏观方面介绍了AAT，旨在为AAT的研究提供一些参考。     

Effects of ear type and weather on the hospital prevalence of canine otitis externa

A retrospective study of 8975 dogs seen at 15 university veterinary medical teaching hospitals in North America (1975 to 1978) found that dogs with pendulous ears and heavy ear canal hair had significantly (P less than 0.01) more otitis externa than dogs with other ear types. Dogs with erect ears, regardless of the amount of ear canal hair, had less risk (P less than 0.01) of the disease than mongrel dogs. Direct evidence is available for the first time showing that monthly variations in ambient temperature, rainfall and relative humidity explain, to a large extent, the monthly variations in the hospital prevalence of canine otitis externa in different geographic regions.     

超低温冷冻对奶牛胚胎超微结构的影响

奶牛冷冻胚胎移植成活率较鲜胚移植明显低.为明确低温冷冻造成胚胎损伤的机理、为冷冻保存方法的进一步改进提供理论依据,利用透射电子显微镜观察了奶牛胚胎常规冷冻和玻璃化冷冻前后的超微结构变化.结果表明,奶牛鲜胚细胞分为两种类型:一种位于内细胞团(ICM)外层,胞质电子致密度低而着色浅,并含有大量的线粒体和内质网;另一种位于ICM中心区域,着色较深,溶酶体的数量多,其余细胞较较少.常规冷冻后,透明带和卵周隙明显变宽,细胞间接触变得松散.囊胚中含有退化的胞核和凋亡小体,内质网变大、变粗,脂滴明显增多.玻璃化冷冻后,ICM细胞的结构发生破坏,部分细胞发生崩解,细胞碎片大量分布于细胞间隙和卵周隙中,并可见大量的脂滴,凋亡细胞和凋亡小体增多.冷冻过程对早期胚胎细胞器的损伤可能是移植后成活率下降的主要原因.     

Treatment of canine otitis externa using video otoscopy

Otitis externa in 27 toy poodles and 40 miniature dachshunds was treated using a video otoscope. A distinct concavity (external tympanic concavity) was observed at the junction between the ventral part of the external surface of the tympanum and the ear canal to which a considerable amount of hair and debris had adhered. All hair and debris adhering to the external tympanic concavity were removed, and systemic antibiotic and antifungal agents were administered, after which all of the dogs recovered. The pattern of hair growth observed in the external tympanic concavity could be characterized according to the breed of dog. All of the toy poodles presented with curly hairs, while the miniature dachshunds had upright or flat-lying hairs.     

Atresia of the external acoustic meatus in a dog

Summary: A 3 year old, female great Dane with atresia of the right external ear canal had recurrent episodes of ear pain. Radiography revealed absence of air in the right external acoustic meatus, thickened bone of the right tympanic bulla and increased radiodensity of the chamber of the bulla. Total ear canal ablation and lateral bulla osteotomy were performed. The superficial portion of the external ear canal was absent and the deeper segment of the vertical ear canal began as a blunt ended cartilage tube. A patent lumen in the existent portion of the external ear canal and the tympanic bulla contained wax, hair and exfoliated squames. The tympanic membrane was not intact. No bacteria were cultured from the contents of the external and middle ear. The dog responded well to surgery and was free of pain 11 months later. Failure to surgically correct atresia of the ear canal in young dogs may allow the accumulation of cellular and sebaceous debris with subsequent involvement of the middle ear in an inflammatory response.     

Morphological Investigations of the Surface Epithelium of Ductuli Efferentes of Black Isogenic Mice (Mus musculus)

Morphological investigations of the epithelial cell types that line the ductuli efferentes (DE) of black isogenic mice confirm absorption of the luminal fluid phase by endocytosis as the main function of ductuli efferentes (DE) in this species. Furthermore, all the histochemical and ultrastructural observations on the DE epithelial histoarchitecture indicate other cellular functions such as exocytosis and probably secretion, including an aprocrine secretory process.     

Spontaneous differentiation of adult rat marrow stromal cells in a long-term culture

It is well recognized that bone marrow stromal cells (MSCs) can differentiate into neuron-like cells when supplemented with growth factors and/or chemical treatments. We demonstrated that primary MSCs obtained from adult rats could spontaneously differentiate into neural precursor cells after long-term culture. During the outset of in vitro culture, less than 0.1% of adult rat primary MSCs expressed nestin, the common protein of neural precursors. These MSCs didn't show neuronal morphology nor express neuronal antigens. In contrast, after continuous maintenance for 6 weeks, a significant subpopulation of MSCs formed cellular clumps and expressed nestin (32.3 +/- 6.3%). Less than 0.1% of cells expressing immature neuron marker betaIII-tubulin could be detected in these prolonged cultured MSCs. After serum deprivation and growth factor supplement, these nestin-positive cells could express neuron-like morphology and neuron-specific markers NF-H, betaIII-tubulin, tau, and neurotransmitter GABA. In contrast, the MSCs without prolonged culture didn't show neuronal morphology nor neuronal markers even after serum withdrawal and growth factors stimulation. These results demonstrated that neural precursors could be obtained from long-term cultured MSCs, and suggested that MSCs should be useful as a potential source for treatment of neurological disease.     

Articular cartilage blood vessels in swine osteochondrosis

Perfusion studies in swine with early lesions of osteochondrosis demonstrated that lamellar areas of chondrocyte necrosis within reserve zones of growth areas occurred only in regions of nonperfused articular cartilage. Articular cartilage with a similar anatomical location was perfused in some animals. Occasionally, nonperfused articular cartilage showed vascular alterations within cartilage canals without evidence of significant perivascular or lamellar necrosis. By light microscopy, some vessels within or adjacent to nonperfused articular cartilage had normal morphology; however, ultrastructural abnormalities were found in some vessels of all cartilage canals adjacent to necrotic cartilage lamella. Minimal alterations were in the few cartilage canal vessels that appeared normal by light microscopy, and the surrounding chondrocytes showed only minimal alterations. Early cartilage canal alterations were seen in the endothelium of cartilage canal capillaries, and ultrastructural changes in these vessels were similar to those described with experimentally induced, direct vascular injury. Vascular injury was followed by leakage of plasma and cells into the interstitial space of the cartilage canal. Necrosis of the vessel wall and interstitial tissue caused the cartilage canals to appear empty or to be filled with fibrin-like material. Although the vascular changes could be considered as part of the normal process of cartilage maturation and cartilage canal chondrification, observations suggest that in domestic swine the attendant cartilage necrosis and chondrolysis is exuberant. It is suggested that alterations in cartilage canal vessels play a major role in the pathogenesis of articular cartilage lesions that are found in osteochondrosis of swine.     

Abstracts of the XXVth Congress of the European Association of Veterinary Anatomists (EAVA). July 28-31, 2004. Oslo, Norway

The oral cavity in vertebrates plays a very important role in food intake mechanics and also contains chemical sensors for food and environmental water. Comparative studies revealed morphological and functional inter‐specific differences that can be correlated to evolutionary events and might represent the adaptation to environmental conditions present in different habitats (Iwasaki, 2002). Particularly these events are strictly dependent on the food intake mechanisms determining the success of the adaptation of vertebrates to their environment and therefore their survival (Roth and Wake, 1989). Since data about the morphology of the zebrafish oral cavity are scarce the aim of the present research was to study it by light, scanning and transmission electron microscopy and immunohistochemistry for some growth factor receptors, i.e. trkA and trkB. The zebrafish was chosen because as a vertebrate it has valuable features as a model for study of vertebrate development (Withfield, 2002). Adult zebrafishes were anesthesized with MS222 and the samples were taken and routinely processed for light and electron microscopy and for indirect peroxidase immunohistochemistry. The topographical and ultrastructural study demonstrated the presence of three different zones. The outer zone is characterized orally by the presence of a papilla and by an epithelium with numerous taste buds that are chemosensory endorgans consisting of modified epithelial cells. Their function is to sample potential food and selecting it according to its edibility (Hansen et al., 2002). Both in upper and lower intermediate zones, the presence of internal valves with a semi‐lunar shape was evident, probably able to regulate the mouth closure. The most internal lower zone corresponds to the tongue that in zebrafish is only a thickening of the pavement mucosa with a stratified epithelium. Immunohistochemistry demonstrated both in upper and lower zones the presence of numerous taste buds that were immunoreactive to TrkA and TrkB‐like neurotrophin receptors, confirming the role of these receptors in taste buds sensory cells (Germanà et al., 2004). The present results give a contribution to the morphological knowledge of the zebrafish oral cavity, an animal model commonly used for developmental studies of vertebrates.     

两株新分离的APMV-I毒株感染SPF鸡的超微病理变化

将APMV-I鹅源分离株YG97鸡源分离株Y98和NDV强毒株F48E8感染SPF鸡，运用透射电镜观察该2株病毒分离株对机体细胞的影响，结果显示3株禽副黏病毒均引起机体肝、胰、脾、肾、心、胃、十二指肠和直肠等实质器官组织细胞的超微病变，如黏膜上皮细胞多处受损，表面微绒毛脱落；实质细胞核固缩、凝聚、凹陷、核多形性，线粒体嵴断裂、空泡样变、膜溶解，粗面内质网扩张、囊泡变，细胞浆的囊泡内及细胞浆内存在有囊膜的成熟病毒粒子等，但YG97和Y98对不同实质器官的组织细胞超微病变程度不一：胃、肝、胰、脾、肾超微病变比心脏的超微病变严重。电镜观察结果还表明：3株禽副黏病毒引起宿主细胞的超微病变有2种形式：坏死性病变和凋亡性病变。     

Ultrastructural identification of small granule prolactin (PRL) cells in goat adenohypophysis by the colloidal-gold method

We describe ultrastructural characteristics of PRL cells with small secretory granules, immunostained with ovine antiserum, in adult Murciano-Granadina milking goats during anoestrus, the last third of gestation and lactation. This cell subtype is considered to comprise a stable population that decreases numerically during gestation and lactation, and that may change during these stages to show large granules.     

Localization of hyaluronic acid in the seminal vesicles of the miniature pig

We studied the detailed localization of hyaluronic acid in the seminal vesicles of the miniature pig, using hyaluronic acid-binding protein as a specific histochemical probe at the ultrastructural level. According to the results, the basolateral surface of the plasma membrane of the glandular epithelial cells, was found to contain hyaluronan. However, abundantly present was hyaluronan in the subepithelial connective tissue, in particular, in the extracellular matrix surrounding the fibroblasts, smooth muscle cells, small blood vessels and capillaries. The substance was also observed in the surface coat of the plasma membrane of the fibroblasts, but not in that of the smooth muscle cells. The findings suggest that hyaluronan in the seminal vesicles of the miniature pig is synthesized onto the surface coat of the plasma membrane of the fibroblasts, is contributed to the extracellular matrix, and consequently concentrates in the subepithelial connective tissue. The substance may particularly be involved in a variety of cellular functions to maintain morphological organization as well as to regulate physiological homeostasis in the reproductive organ of this species, rather than participate in sperm functions.