首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 78 毫秒
1.
The lumbar spinal cord segment of the camel embryo at CVRL 2.4 to 28 cm was examined. Major changes are occurring in the organization of the lumbar spinal cord segments during this early developmental period. At the CVRL 2.4, 2.7 and 3.6 cm the three primary layers, ependymal cells layer, mantle cells layer, marginal cells layer in the developing lumber spinal cord segment were demonstrated. The mantle layer is the first to show striking differentiation, while the marginal layer is represented by thin outer rim. Proliferation and differentiation of the neuroepithelial cells in the developing spinal cord produce the thick lateral walls, thin roof and floor plates. The spinal ganglion and dorsal root of the spinal nerve are differentiated. At 2.7 cm CVRL differential thickening of the lateral walls produces a shallow longitudinal groove called sulcus limitans , which separates the dorsal part (alar plate) from ventral part (basal plate). The ventral root of the spinal nerve, the spinal cord and ganglion are embedded in loose mesenchyme, which tends to differentiate into spinal meninges. At 3.6 cm CVRL the basal plate, which is the future ventral gray horn, seem to be quite voluminous and the dorsal and ventral roots unite to form the beginning of the spinal nerve. At 5.5 cm CVRL the alar plates enlarge forming the dorsal septum. At 8.4 cm to 10.5 cm CVRL the basal plates enlarge, and bulge ventrally on each side of the midline producing the future ventral medium fissure, and the white and gray matters can be recognized. At 28 cm CVRL the lumen of the spinal cord is differentiated into the central canal bounded dorsally and ventrally by dorsal and ventral gray commissures, and therefore the gray matter takes the appearance of a butterfly.The lumber spinal nerve and their roots are well distinguished.  相似文献   

2.
With 14 figures and 3 tables SUMMARY: Each adrenal gland consisted of cortex and medulla that developed from different embryological origins and presented different cellular organization. One hundred male or female camel embryos or fetuses with crown vertebral rump lengths (CVRL) that ranged from 0.8 to 117 cm were examined. The adrenal cortex, which is derived from intermediate mesoderm, was first observed in the 0.8-cm CVRL camel embryo. The adrenal cortex initially was combined with the gonad as a thickened region of proliferating cells derived from splanchnic intermediate mesoderm. Adrenocortical tissue was first separated from the gonadal tissue in the 2-cm CVRL camel fetus and was observed as a separate dorso-medial mass of cells. At 2.5-cm CVRL, the adrenocortical tissue was surrounded by a capsule of undifferentiated mesenchymal cells, except at its proximal pole, where an invagination was located through which chromaffinoblast cells entered the cortex. The chromaffinoblast cells migrated from the neural crest to form the medulla of the developing adrenal gland. In the 3.5-cm CVRL camel fetus, the adrenocortical cells differentiated into two layers: the inner fetal cortex and the outer definitive cortex. As development proceeded, the fetal cortex degenerated and the definitive cortex formed the zona glomerulosa and zona fasciculata. The zona reticularis did not form until the end of gestation. During prenatal life, the adrenal medulla was much thicker than the cortex.  相似文献   

3.
The present investigation examined histogenesis of epithelial, stromal and angiogenic elements of the prenatal camel permanent or metanephric kidney. The primitive metanephros was first observed at the 13‐mm crown vertebral rump length (CVRL) stage as an ovoid structure composed of a centrally located epithelial ureteric bud and peripheral circumscribed masses of undifferentiated mesenchymal cells. The first morphological evidence of glomerulogenesis was observed at the 28‐mm CVRL stage. Developing renal corpuscles became obvious at the 35‐mm CVRL stage. At the 60‐mm CVRL stage, the epithelial renal pelvis gave rise to tubular branches that extended towards the cortical zone. These branches represented the presumptive collecting ducts. Differentiation of renal tubules into the proximal and distal convoluted tubules was observed at the 95‐mm CVRL stage. At the 130‐mm CVRL stage, the renal medulla was clearly delineated into medullary pyramids, which in association with the corresponding cortical caps formed the morphological basis of the renal lobar formation. A gradual nephrogenic decline was noticed from the 940‐mm CVRL on; however, the process of nephrogenesis persisted throughout all the studied foetal stages.  相似文献   

4.
The study of the development of the mesonephros in the camel (Camelus dromedarius) was carried out on 16 embryos ranging from 0.9 to 8.6 cm crown vertebral rump length (CVRL). At 0.9 cm CVRL, the mesonephros is represented by a narrow strip along the roof of the thoracolumbar part of the vertebral column. At 1.4 cm CVRL, some of the mesonephric tubules are canalized but others are still solid. The mesonephric corpuscles are well developed at 1.9 cm CVRL and occupy almost the entire abdominal cavity in between the liver and the gut. Histologically, the glomeruli occupy the ventromedial aspect of the mesonephros while the mesonephric tubules become numerous, larger and more coiled. At 3 cm CVRL, the metanephros is invaginated in the caudal pole of the mesonephros, and the mesonephric tubules in some areas are differentiated into secretory and collecting tubules. At 3.5 cm CVRL the mesonephros is related dorsally to the postcardinal vein and ventrally to the subcardinal vein. At 4.7 cm CVRL continuous regression of the mesonephros from cranialwards to caudalwards is observed. At 5.3-5.5 cm CVRL, the cranial part of the mesonephros is divided into medial and lateral regions, and later the medial region completely disappears and is replaced by the primordium of the adrenal gland. At 8.6 cm CVRL, the caudal part of the mesonephros completely disappears.  相似文献   

5.
The development of retina in Indian buffalo (Bubalus bubalis) has not been reported previously. The aim of the present study was therefore to report the major landmarks and the time course in the development of retina. Serial histological sections of Indian buffalo embryos and foetuses were used as group1 (<20.0 cm CVRL), group2 (>20.0 but <40.0 cm CVRL) and group3 (>40.0 cm CVRL). Age estimation was made on the basis of crown vertebral‐rump length (CVRL), which ranged between 36 and 286 days (1.6–94.0 cm). The retina in Indian buffalo was developed in a similar manner to that of the other mammals with the principal differences in the time of occurrence of various layers of this nervous tunic. In 36 days (1.6 cm stage), the foetal retina was composed of pigmented layer and the layer of neuroblasts. Differentiation of layers was first observed in 47 days (4.0 cm CVRL) which became prominent in 52 days (5.1 cm stage). At 120 days (20.5 cm stage), the differentiation of inner plexiform layer and inner nuclear layer was evident. At 143 days (31.0 cm) foetal age, the faint line in neuroblastic layer was the first evidence of the future outer plexiform layer. In foetuses of group III, the retina was comprised of all 10 layers (eight cell layers and two membranes) viz. pigmented epithelium, layer of rods and cones, outer limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, layer of nerve fibres and the inner limiting membrane.  相似文献   

6.
A nine-year-old neutered male domestic shorthaired cat with a history of spinal pain and progressive hindlimb dysfunction was presented to the Norwegian School of Veterinary Science. Following neurological and myelographic examination, an intramedullary mass affecting several lumbar spinal cord segments was diagnosed. A neoplastic lesion was suspected and a poor prognosis was given. On postmortem examination, the spinal cord was found to be dorsally flattened from the 12th thoracic vertebra to the fifth lumbar vertebra and severely thickened with a dorsal cleft from the fifth to the seventh lumbar vertebra. Histologically, the tumour was diagnosed as an anaplastic astrocytoma.  相似文献   

7.
Studies of ocular development in the dromedary camel (Camelus dromedarius) have not been reported previously. The aim of the present investigation was therefore to document the major landmarks and the time course in the prenatal development of the eye tunics in dromedary camel and its accommodation with the surrounding hard environment of the desert. Serial histological sections of dromedary camel embryos and foetuses were used. Age estimation was made on the basis of gestational size, crown vertebral‐rump length (CVRL), which ranged 1.2–110 cm. The eye of the dromedary camel developed in a similar manner to that of the human and domestic animals eyes; the principal differences were in the time of occurrence of certain developmental events, pigmented peripheral cornea near the limbus, a remarkably thickened Descemet's membrane and pigmentation in the corneo‐scleral junction, which represent an adaptive modification in relation to a severe environment.  相似文献   

8.
A 24-day-old, 2.2-kg, female Reeves' muntjac (Muntiacus reevesi) acutely developed left hind limb lameness that resolved with rest and anti-inflammatory drugs but recurred at 8 mo of age. Magnetic resonance imaging (MRI) of the lumbar, sacral, and coccygeal spine revealed a fluid-filled dilatation of the central canal of the spinal cord, which was interpreted as a hydromyelic cyst. Surgical exploration and drainage of the cyst were attempted. Despite initially improved mobility, severe plantar ulceration of both hocks developed. The animal was euthanatized. Gross necropsy of the central nervous system revealed a 1.5-cm-long, mild depression with associated yellowing of the dorsal spinal cord in the lumbosacral region, dilatation of the central spinal canal that extended from the cranial thoracic spinal cord with diameter increasing caudally, and mild herniation of the brainstem at the foramen magnum. Histopathologic lesions of the central nervous system were restricted to the spinal cord, with equivocal enlargement of the fourth ventricle. Pathologic changes included irregular dilatation of the central canal, flattening to the absence of the ependymal cells, spongiosis of the gray matter neuropil, and dystrophic calcification. The gross and histologic findings confirmed the diagnosis of hydromyelia.  相似文献   

9.
本研究旨在利用微卫星标记分析阿拉善戈壁双峰驼的遗传多样性,寻找与其体尺性状相关联的微卫星标记,为阿拉善戈壁双峰驼的标记辅助选择提供参考。试验利用非变性聚丙烯酰胺凝胶电泳技术,检测17个微卫星标记在阿拉善戈壁双峰驼群体中的多态性,并与其体尺性状进行相关性分析。结果显示,17个微卫星标记共检测到60个等位基因,平均有效等位基因数为2.7302,平均杂合度为0.6205,平均多态信息含量为0.5308,可见阿拉善戈壁双峰驼群体的遗传多样比较丰富。微卫星标记多态性与阿拉善戈壁双峰驼体尺性状的关联分析发现,有8个微卫星标记（LCA82、LCA90、CMS15、CMS36、CMS104、CVRL01、YWLL36和YWLL44）与不同体尺性状有一定的关联性,尤其是CMS36和YWLL44与所测体尺性状均有关联,其中CMS36不同基因型的体长和体重均有显著差异（P<0.05）,具体表现为BB > AA > AB,AA和BB基因型的体高、胸围、管围均显著高于AB基因型（P<0.05）;YWLL44的AC基因型体高、胸围和体重均显著高于BD基因型（P<0.05）,AC基因型的体长显著高于AB和BD基因型（P<0.05）,AB和AC基因型的管围显著高于BD基因型（P<0.05）。研究表明,8个微卫星标记对阿拉善戈壁双峰驼体长有一定影响,CMS36和YWLL44对其体高有影响,LCA82、LCA90、CMS36、CVRL01、YWLL36和YWLL44对其胸围有影响,LCA82、CMS15、CMS36、CMS104、CVRL01和YWLL44对其管围有影响,LCA82、LCA90、CMS15、CMS36、CVRL01和YWLL44对其体重有影响。  相似文献   

10.
The paper presents some salient aspects of a study on the placentation of camel at gross, light and electron microscopic levels. The study involved factors analysis on five pregnant uteri from camel slaughter house in Yazd, Iran.
The experimental observations confirmed that unlike other animals, in camel, the fetus only developed in the left horn of the uterus. Based on the distribution type of the chorionic villi, in camel, similar to horse, the placenta was found to be in diffused form. At light microscopic level, the results revealed six layers between the fetal and maternal blood. From this it inferred that camel's placenta was also of epitheliochorial form.
The detailed examination further showed that similar to cow and sheep umbilical cord in camel was also limited to the amniotic sac but it contained two arteries, two veins and one urachus. Little amount of elastic fibers were also observed in the histological and electron microscopical sections. At the electron microscopic level, both binucleated and mononucleated cells in trophoblastic layer were confirmed.  相似文献   

11.
Computed tomography (CT) has been applied previously for assessment of canine spinal disease using a multitude of different technical imaging parameters. The purpose of this study was to establish an optimized imaging protocol for the cervical and lumbar canine spine using a single-detector-row helical CT unit. Thin slice thickness (1–2 mm), low pitch (axial scan mode, helical pitch <2), and medium-frequency image reconstruction algorithm significantly improved the visibility of the intervertebral disk and spinal cord. Tube current, helical reconstruction interval, and the use of an additional edge enhancement filter had no significant effect on the visibility of the intervertebral disk and spinal cord. There was also no interaction between the use of an additional edge enhancement filter and image reconstruction algorithm. Use of an additional edge enhancement filter introduced a double ring artifact in the periphery of the spinal canal lumen that did not correspond to the spinal cord or pachymeningeal margin.  相似文献   

12.
Amy S.  Tidwell  DVM  Andrew  Specht  DVM  Lauren  Blaeser  DVM  Marc  Kent  DVM 《Veterinary radiology & ultrasound》2002,43(4):319-324
Myelography and magnetic resonance imaging (MRI) were performed on a 4-year-old neutered female Rottweiler with bilateral pelvic limb paresis. On the myelogram, there was extradural spinal cord compression at the level of the T11-12 intervertebral disc. Inadvertent placement of epidural contrast medium also allowed identification of a 1-cm circular filling defect in the epidural space dorsal to the compressed spinal cord. MRI showed partial loss of the nucleus pulposus signal of the T11-12 disc, a focal signal void within the vertebral canal at T11 compatible with a free disc fragment, and extradural masses compressing the spinal cord at T10-11 and T11-12. Hemorrhage within the masses was confirmed on T2*-weighted images. A mixture of hematoma and mineralized disc material was found at surgery, and there was no histopathologic evidence of neoplasia. In this article, the appearance on MRI of hemorrhage associated with intervertebral disc herniation is discussed.  相似文献   

13.
The central nervous system (CNS) of DBA/2 mice inoculated i.p. with the D variant of encephalomyocarditis virus (EMC-D) (10(3) PFU/head) was examined up to 28 days postinoculation (28 DPI). The virus titer of CNS reached a maximum level at 4 DPI, and infectious viruses became undetectable by 28 DPI. Histopathologically, degeneration of neurons with virus antigens was observed in St. pyramidale hippocampi, Nuc. amigdaloideus corticalis and St. granulosum cerebelli of the brain and in Cornu ventrale of the thoracic to lumbar spinal cord at 6 DPI. In addition, in the spinal cord, demyelination was found in Funiculus ventralis and Funiculus lateralis at 6 DPI and it progressed to form spongiosis at 10 DPI. In correspondence with these virological and histopathological findings, hind limb paralysis developed in some mice at 6 DPI, and its incidence increased markedly to about 60% at 10 DPI.  相似文献   

14.
The development of the parotid gland was examined in 36 bovine embryos and foetuses with a crown-rump-length (CRL) from 28 up to 1000 mm by light, transmission electron microscopical and actin-immunohistochemical methods. The anlage of the parotid gland in an embryo with 28 mm CRL can be found at the lateral angle of the primitive oral cavity as a local thickening of the epithelium. During the second month, the differentiation of primary ducts and endbuds starts and a lumen develops in the primary ducts. At the end of the second month a lumen appears in the terminal endbuds. In the immature endpiece cells first secretory granules can be seen from a CRL of 240 mm. In the third month differentiation between intra- and inter-lobular ducts is possible. Immature myoepithelial cells present as a basal layer of flattened cells between the epithelial cells and the basement membrane at the end of the second month. During further development they increase in number, become more flattened and form long cellular processes. At the end of the fourth month isolated actin filament bundles are formed, which were also detected by an antibody against smooth muscle actin. The actin filaments condense continuously until they fill the cell processes completely at the end of foetal development.  相似文献   

15.
A vertebral body abscess extending into the epidural space causing spinal cord compression was diagnosed in the cervical spinal cord in four lambs and the thoracic spinal cord in four lambs. The affected lambs were aged between 4 and 10 weeks and clinical signs had been present for 7-21 days before veterinary examination. Treatment with high doses of penicillin did not result in an improvement of the neurological signs and all lambs were destroyed on humane grounds. Collection and analysis of cerebrospinal fluid (CSF) revealed a significant increase in the protein concentration in lumbar compared to cisternal CSF samples. There was a neutrophilic pleocytosis in two lumbar CSF samples. In lambs aged between 4 and 10 weeks with no history of previous locomotor dysfunction, paresis of more than 1 week duration may be suggestive of a vertebral body abscess which has extended into the epidural space causing spinal cord compression. Stagnation of CSF caudal to the lesion results in an increased protein concentration in the lumbar sample.  相似文献   

16.
A 5-day-old male crossbred beef calf presented with a well-coordinated bilateral hopping gait of the hind limbs. Postmortem CT showed a poorly defined oval-shaped region at the L3–L4 spinal segments, which had high signal intensity on T2 weighted postmortem MRI images. On pathological examination, we identified a large cystic cavity filled with a large amount of cerebrospinal fluid on the cut surface of the spinal region. Histopathological examination revealed that the spinal cord parenchyma was compressed by the cystic structure, and the cystic cavity was lined with a thin layer of discrete ependymal cells, indicating syringohydromyelia. This is the first reported case of a Holstein-Friesian × Japanese Black crossbred calf with solitary syringohydromyelia. Our findings suggest that myelodysplasia with cystic cavities can be suspected by CT, without the need for MRI.  相似文献   

17.
To characterize spinal cord effects of needle placement using lumbar puncture myelography technique, lumbar puncture was performed in 5 dogs and computed tomography images of the spinal column were acquired in the transverse plane at the level of the puncture site after contrast injection and both before and after needle removal. The spinal cords were punctured during needle placement and parenchymal contrast enhancement was present in 4 of 5 dogs. Although no dogs exhibited overt neurological abnormalities following computed tomographic imaging, hemorrhage, gliosis and axonal degeneration were confirmed microscopically in all subjects. These results suggest that spinal cord morbidity is induced when lumbar myelography is performed using currently accepted technique.  相似文献   

18.
Phosphorylation of caveolin-1 occurs during cell activation by various stimuli. In this study, the involvement of caveolin-1 in an irradiation injured spinal cord was examined by analyzing the phosphorylation of caveolin-1 in the spinal cord of rats after irradiation with a single dose of 15 Gray from a 60Co γ-ray source at 24 h post-irradiation (PI). A Western blot analysis showed that the phosphorylated form of caveolin-1 (p-caveolin-1) was expressed constitutively in the normal spinal cords and was significantly higher in the spinal cord of irradiated rats at 24 h PI. The increased expression of ED1, which is a marker of activated microglia/macrophages, was matched with that of p-caveolin-1. In the irradiated spinal cords, there was a higher level of p-caveolin-1 immunoreactivity in the isolectin B4-positive microglial, ependymal, and vascular endothelial cells, in which p-caveolin-1 was weakly and constitutively expressed in the normal control spinal cords. These results suggest that total body irradiation induces activation of microglial cells in the spinal cord through the phosphorylation of caveolin-1.  相似文献   

19.
Forty-seven cases of neonatal vertebral fractures/luxations occurred in a 21 year period (1967-1987). All of the fractures were located between the 11th thoracic vertebra and the fourth lumbar vertebra; 77% occurred at the thoracolumbar junction. All but one case was associated with a forced extraction, either unspecified (53%), mechanical (28%), or manual (17%).

A weak calf or continuous recumbency since birth was the major clinical sign. Hemorrhage around the kidneys, adrenal glands, and in perivertebral muscles was a consistent necropsy finding and a useful indicator that a thoracolumbar fracture was present. In addition to the vertebral fracture, the prominent necropsy findings were subdural and epidural hemorrhage, myelomalacia, spinal cord compression or severed spinal cord, and fractured ribs. All of the calves died or were euthanized without regaining locomotory function.

  相似文献   

20.
The purpose of this study was to discover whether the use of different doses of oxytetracycline causes any alteration in the development of nervous tissue in rainbow trout embryos. Five thousands eggs of females rainbow trout were divided into five groups. One group acted as control and the other four were administered with one of four doses of oxytetracycline, 0.025, 0.050, 0.100, or 0.201 microM, at the moment of fertilization. The eggs were incubated under pisciculture conditions to just before being ready to spring off. From the 10th day, 10-egg samples were taken regularly and fixed. Five were processed for histological techniques and stained with haematoxylin and eosin, cresyl fast violet and silver, the other five were homogenized for antibiotic detection. Histological alterations appeared in 37-day-old embryos, with an abnormal migration of the neuroblasts to the marginal layer of the neural cord, and alterations in the development of the lens and eye layers. Some embryos showed abnormal curvature of the spinal cord but these changes were not statistically significant.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号