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1.
Nerve sheath fibrosarcomas of the left 5th through 8th cranial nerve roots were diagnosed in 1 dog and of the left 4th through 8th cranial nerve roots in another dog. Clinical signs in both dogs included head tilt to the left, circling to the left, left hemiparesis and proprioception deficits, rotary nystagmus, left-sided atrophy of masticatory muscles, and cutaneous hypalgesia of the left side of the face. Cranial nerve roots from both dogs were incorporated in discrete, firm, encapsulated, lobulated, tan masses of various sizes that compressed adjacent brain stem and cranial nerves. There were no regional or distant metastases; however, there was enlargement of nerve roots adjacent to the masses. The masses were composed of bundles and sheets of anaplastic, polymorphic to spindle-shaped cells that infiltrated cranial nerves and ganglia and extended into the brain along nerve roots. Masses contained various amounts of collagen and reticulin fibers, but no mucopolysaccharide ground substance. There was no myelin or S-100 protein associated with neoplastic cells. The tumors appeared to have a multicentric origin from cranial nerve sheaths.  相似文献   

2.
A 5-month-old female Border Collie was evaluated because of progressive hind limb ataxia. The predominant clinical findings suggested a sensory neuropathy. Sensory nerve conduction velocity was absent in the tibial, common peroneal, and radial nerves and was decreased in the ulnar nerve; motor nerve conduction velocity was decreased in the tibial, common peroneal, and ulnar nerves. Histologic examination of nerve biopsy specimens revealed considerable nerve fiber depletion; some tissue sections had myelin ovoids, foamy macrophages, and axonal degeneration in remaining fibers. Marked depletion of most myelinated fibers within the peroneal nerve (a mixed sensory and motor nerve) supported the electrodiagnostic findings indicative of sensorimotor neuropathy. Progressive deterioration in motor function occurred over the following 19 months until the dog was euthanatized. A hereditary link was not established, but a littermate was similarly affected. The hereditary characteristic of this disease requires further investigation.  相似文献   

3.
The effects of alkylmercurial poisoning were studied in 16 pigs poisoned with daily oral doses of a fungicide containing methylmercury 2, 3-dihydroxy propyl mercaptide and methylmercury acetate. Clinical signs included weakness, wobbling gait, blindness, recumbency and death. Microscopic studies of the peripheral nervous system revealed Wallerian degeneration in sensory fibers and neuronal degeneration in dorsal root ganglia. In the central nervous system, there were neuronal degeneration of ischemic type, glial degeneration, gliosis and necrosis of the media of meningeal arterioles. The last mentioned lesion was not extensive.

The sequential development o lesions and the absence of segmental demyelination suggest that the primary lesion in the peripheral nervous system was neuronal-axonal degeneration rather than degeneration of the Schwann cell and myelin sheath.

  相似文献   

4.
Canine ganglioradiculitis (sensory neuropathy) was examined pathologically in two dogs (dog Nos. 1 and 2). The affected dogs had 1 and 2 years clinical courses from the onset, respectively. As common clinical signs, both cases showed progressive ataxia, difficulty in prehending food, visual deficit, and several sensory abnormalities. Gross observation after tissue fixation revealed whitish discoloration in the dorsal column of the spinal cords. The histological lesions were mainly distributed in the spinal dorsal roots, ganglions, and dorsal columns. In the spinal dorsal roots and ganglions, there were striking myelin loss, mild infiltration of mononuclear cells, and proliferation of small spindle cells. In the dorsal funiculus, there were moderate to severe diffuse myelin-loss and axonal degeneration. Immunohistochemistry for substance P (SP) revealed marked reduction of SP-immunopositive granules in the spinal substantia gelatinosa of affected dogs. By immunohistochemistry, CD3-positive cells were observed in the dorsal roots of dog No. 2, while CD3-positive cells were rare in those of dog No. 1. In the spinal ganglion of dog No. 1 there were many CD3- and MHC class II-positive cells. By indirect immunofluorescence assay using sera from affected dogs, no autoantibodies against canine nerve tissues were detected. The clinicopathological features of the present cases are almost consistent with those in previous reports of canine sensory neuropathies, while the etiology remains unclear.  相似文献   

5.
A male 14-year-old Arab horse was pathologically diagnosed as equine motor neuron disease (EMND), which was kept as a breeding horse on a farm in Tokachi district of Hokkaido in Japan. On examination of the peripheral nerves, the most characteristic feature was Wallerian-type degeneration revealed by myelinoclasis associated with myelin ovoids which were sometimes infiltrated by macrophages. The other abnormalities were axonal swellings which were surrounded by thin myelin sheaths. Ultrastructurally, the axonal swelling was due to an accumulation of neurofilaments, and was accompanied by a thin and degenerating myelin sheaths. In teased nerve fiber preparations, the most conspicuous change was myelinoclasis represented by segmentation into myelin ovoids or balls. Occasionally, segmental demyelination and axonal degeneration characterized by multifocal axonal swelling were observed.  相似文献   

6.
Sixteen of 17 sheep with spontaneous listeric encephalitis had neuritis characterized by diffuse and focal intrafascicular and perineural accumulations of lymphocytes, plasma cells, macrophages and neutrophils in one or more cranial nerves. Nine sheep had extensive trigeminal neuritis which was usually unilateral. Brain lesions were mainly in the stem and were foci of macrophages or neutrophils or both, malacia, neutrophilic neuronophagia, vascular cuffing, and meningitis. Lesions in the brain and trigeminal ganglia were most severe on the same side as the affected trigeminal nerve. Gram-positive bacilli were in proximal parts of cranial nerves in foci of inflammatory cells and occasionally in morphologically intact nerve fibers. Organisms in the brain were in phagocytes in areas of inflammation and in scattered neurons and axons. The results were consistent with centripetal migration of the infectious agent along one or more branches of the trigeminal nerve to the brain and dissemination in the brain stem occurring, at least partly, along fiber tracts. Intraaxonal movement of bacteria probably is a mechanism involved in the pathogenesis of this disease.  相似文献   

7.
The lesions caused by excess oral pyridoxine hydrochloride (150 mg/kg body weight/day) and clioquinol (200 mg/kg body weight/day), given individually and in combination to adult Beagle dogs, were evaluated. The experimental period was 100 to 112 days, except that four dogs in each of the clioquinol and combined-treatment groups were killed early because of severe debilitation or neurologic disease, and one dog given both compounds died on the third day of compound administration. Degenerative neurologic lesions had distribution specific for the compound given. Pyridoxine-treated dogs had lesions limited to tracts and nerves with neuronal bodies of their nerve fibers in the spinal and trigeminal ganglia. Clioquinol-treated dogs had neurologic lesions limited to the central nervous system. The most lesions were in the rostral dorsal funiculus and distal aspects of the optic nerve fibers, but minimal to mild degenerative changes also occurred in distal aspects of the corticospinal and spinocerebellar tracts. Dogs given both pyridoxine hydrochloride and clioquinol had a combination of the lesions in dogs given pyridoxine or clioquinol individually. Several dogs given clioquinol or pyridoxine plus clioquinol had extraneural lesions, including myocardial degeneration and thyroidal alterations.  相似文献   

8.
Gross changes and other necropsy findings in 36 purebred Brown Swiss cattle affected with bovine progressive degenerative myeloencephalopathy were nonspecific. Primary microscopic lesions were confined to the central nervous system, specifically the white matter of the spinal cord, axons in some brainstem nuclei, and Purkinje cells of the cerebellar cortex. Spinal cord lesions involved only the white matter and consisted of axonal degeneration, loss of axons and myelin, and status spongiosus. Axonal degeneration was characterized by swelling and fragmentation of the axoplasm or formation of large, discontinuous swellings referred to as spheroids. Lesions were qualitatively similar at all levels, but quantitatively dissimilar in the same funiculi at different levels. Both ascending and descending fibers were involved but correlation to specific fasciculi was not evident. Lesions always were most severe in thoracic spinal cord segments. Little or no astroglial response, no inflammatory response, and no involvement of gray matter were observed in the spinal cord. Cerebellar lesions were limited to selective degeneration and loss of Purkinje cells and occasional swelling of Purkinje cell axons (torpedos) in the granular layer of the cerebellar cortex. Brainstem lesions were inconsistent and limited to occasional axonal swelling in brainstem nuclei. The pathogenesis of bovine progressive degenerative myeloencephalopathy is unknown and possible mechanisms were discussed. The disease exhibits a familial pattern in Brown Swiss cattle and may be hereditary. Extraneural lesions were considered secondary to central nervous system lesions.  相似文献   

9.
Degenerative lesions in the spinal cord white matter of 12 English Foxhounds and two Harriers between 3 and 6 years old were associated with a diet composed mainly of ruminant stomachs. Lesions were present throughout the length of the spinal cord and were more severe in ventral and lateral columns than in dorsal columns. Degenerate fibers were accompanied by astrocytic proliferation. Changes suggestive of a primary myelinopathy included vacuolated myelin sheaths around apparently intact axons and thick-thin transitions in myelin sheath thickness. Mixed sensory and motor peripheral nerves and muscle histochemical fiber type profiles appeared normal. Similarities were noted with the changes described in subacute combined degeneration of the spinal cord in human beings, a neuropathy caused by methionine and methylation deficiency in patients with vitamin B12 deficiency. Mean serum methionine levels were significantly lower (P greater than 0.01) and mean liver methionine synthetase levels were significantly greater (P greater than 0.01) in affected dogs restored to a balanced diet than in age-matched controls maintained on the balanced diet. The elevated methionine synthetase levels possibly reflected compensatory reactions to the associated dietary change.  相似文献   

10.
This study was carried out to describe morphologically and morphometrically the hypoglossal dorsal root and its ganglia, using heads of 20 adult Holstein cattle of both sexes. The dorsal root of the hypoglossal nerve (XII) has always an evident dorsal root ganglion (DRG) including the accessory in 30% (6 of heads) or satellite ganglia in 10% (2 of heads). There were statistically significant differences between the lengths (right: 8.64+/-0.22 mm, left: 7.91+/-0.31 mm, p<0.01) of peripheral roots of the DRG in male. Statistical significance existed in the lengths (right: 7.01+/-0.43, left: 8.27+/-0.47, p<0.05) of the central roots of the DRG in male. Since the histological findings showed that each ganglion placed on the dorsal root of the XII had the general feature of a spinal ganglion, it can be said that the XII has the intracranial peripheral (sensory) fibers and carry directly sensory input to the brain stem. In conclusion, the present study is the first to reveal the morphology of the hypoglossal dorsal root with ganglia in Holstein cattle.  相似文献   

11.
The optic nerve fiber layer (NFL) of the chicken retina was studied quantitatively and morphologically at 17 positions along seven radially arranged bands from the dorsal tip of the pecten oculi using electron microscopy. The number of nerve fibers was counted in areas 6 microm in width x the full thickness of the NFL. Myelinated nerve fibers in the NFL were also identified immunohistochemically using anti-myelin basic protein serum. The dorsal area (dorsal, dorso-temporal and dorso-nasal bands) in the retina had thin NFL and contained the largest number of nerve fibers, which were mainly thin and unmyelinated. The ventral area (ventral and ventro-temporal bands) had a thick NFL and contained a relatively small number of nerve fibers, many of which were myelinated. The nasal band had the thickest NFL and contained as many nerve fibers as the dorsal area, with the temporal band showing a high ratio of myelinated fibers. The band had a thick NFL and contained many nerve fibers with a relatively low ratio of myelinated fibers. The relationship between the number and composition of nerve fibers in the NFL to the chicken visual characteristics was discussed. Although the myelin in the chicken retina was loose type, the myelin-forming cells were similar in appearance to dense oligodendrocytes. retina, morphometry, myelinated fiber, nerve fiber layer.  相似文献   

12.
The spinal nerve root origins of the cutaneous nerves innervating the canine pelvic limb were determined in 12 barbiturate-anesthetized, healthy dogs by stimulating the dorsal roots L1-S3 and recording the evoked-action potentials from each cutaneous nerve. The dogs were then euthanatized, identification of each dorsal root and cutaneous nerve was verified by dissection, and the type of lumbosacral plexus (prefixed, median fixed, or postfixed) was determined. With one exception, the dorsal cutaneous branches and lateral cutaneous branches of L1-L3 originated only from their corresponding spinal nerve roots. The genitofemoral nerve received afferent fibers predominantly from L3-L4 nerve roots. The lateral cutaneous femoral nerve originated from L3-L5 nerve roots, and the saphenous nerve from L4-L6 nerve roots. The proximal caudal cutaneous sural nerve originated from L6-S1. The lateral cutaneous sural nerve originated from L5-S1; the deep and superficial fibular nerves arose primarily from L6-L7. The distal caudal cutaneous sural nerve originated predominantly from L7-S1, and the medial cutaneous tarsal nerve originated from L6-S1. The medial plantar nerve originated predominantly from L6-S1 roots, whereas the lateral plantar nerve originated from L6-S2 roots. The middle clunial nerve received afferent fibers primarily from S1-S2; the caudal clunial nerve received fibers from S1-S3. The caudal cutaneous femoral nerve originated predominantly from L7-S2. The dorsal nerve of the penis originated predominantly from S1-S2, and the superficial perineal nerve originated from S1-S3. One dog had a prefixed plexus, 8 dogs had median-fixed plexuses, and 1 dog had a postfixed plexus.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
Serial peripheral nerve biopsies from two golden retriever littermates with chronic neurologic disease were taken for morphologic and morphometric evaluation. Teased nerve preparations were difficult to interpret due to the lightness of myelin staining. Light and electron microscopic findings were characterized by the following: reduced number of myelinated axons, presence of myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, increased numbers of Schwann cell nuclei, increased concentration of neurofilaments in myelinated axons, many Schwann cells with voluminous cytoplasm, and increased perineurial collagen. Onion bulb formation was not seen. In contrast to control data, a poor correlation was seen between numbers of myelin lamellae (ML) and axonal circumference (AC). The frequency distribution of ML ranged from 5 to 55 lamellae in affected animals (mean, 28 lamellae) compared to 20 to 140 lamellae in controls (mean, 66 lamellae). The ML/AC ratio was significantly reduced (P less than 0.001) in nerves of affected dogs. Morphometric results indicated that fibers of all calibers were hypomyelinated.  相似文献   

14.
The neurotoxicity of aniline and its age-dependent responses were investigated in male rats. Groups of 6 rats, 4-week-old, were treated once with aniline (500, 750 or 1,000 mg/kg) or olive oil by gavage. Additional groups of 6 rats, 7- or 10-week-old, were treated once with 800 mg/kg of aniline or olive oil. Paralytic gait or hindlimb paralysis was observed between post-treatment days 8 and 15 in two out of six rats receiving 1,000 mg/kg of aniline at 4 weeks of age. On post-treatment day 15, spongy change in the white matter of the spinal cord was observed in all rats receiving 750 or 1,000 mg/kg of aniline at 4 weeks of age. The lateral and ventral columns of the thoracic spinal cord were the most severely affected. Spongy change in the facial nerve and spinal trigeminal tracts of pons and medulla oblongata, and mild degeneration of the peripheral nerves was found in 3 out of 6 rats receiving 1,000 mg/kg of aniline. At the ultrastructural level, the spongy change was due to distention of the myelin sheath and splitting of the intraperiod line. Axons were well preserved in the affected nerve fibers. No abnormalities were seen in the neuronal cell bodies. Although transient cyanosis was observed in all rats receiving 800 mg/kg of aniline at 7- or 10-week-old, as well as in rats receiving 750 or 1,000 mg/kg of aniline at 4-week-old, no treatment-related neurobehavioral or morphologic abnormalities were found in the former. These findings demonstrate the neurotoxicity of orally administered aniline for rats, depending upon the age of the animal at the time of administration.  相似文献   

15.
Unilateral degeneration of the retina and optic nerve was observed among Fischer-344 (F-344) rats fed a semi-purified synthetic feed. Further studies were conducted using standard cereal-based and synthetic diets. Beginning at 4 weeks of age, all experimental rats (169 F-344 rats) were fed various diets and were examined for morphologic and functional changes in the retina and optic nerve. No ocular lesions were observed in any F-344 rats prior to 21 weeks of age, whether fed a synthetic diet or a standard diet; however, approximately 16% (13/86) of the F-344 rats examined between 57 and 64 weeks of age developed unilateral degeneration of the retina and optic nerve. On the other hand, the F-344 rats fed the synthetic diet developed the degenerative lesions by 30 weeks of age, while the F-344 rats fed the standard diet did not develop lesions over this shorter time period. Degenerative changes of the affected retinas and optic nerves were closely related with functional abnormalities evaluated by electroretinogram and visual evoked potentials. In contrast with the F-344 rats, Long-Evans rats that were fed either the synthetic or standard diet up to the age of 68 weeks (77 rats) did not develop the ocular lesions. There was no apparent relationship of the development of the lesions with dietary modification, toxicity or trauma; thus, these observations appear to indicate that spontaneous unilateral degeneration of the retina and optic nerve occurs in F-344 rats and that these ocular lesions may be accelerated by the feeding of certain semi-purified synthetic diets.  相似文献   

16.
Striped skunks (Mephitis mephitis) were inoculated with street rabies virus and immunosuppressed with several doses of cyclophosphamide. Control skunks were inoculated with street virus only. The skunks were killed in terminal stages of the disease and several tissues were collected for examination by immunofluorescence, light microscopy and viral titration. Sera collected at euthanasia from most of the principals did not contain detectable rabies neutralizing antibodies, whereas high titers occurred terminally in controls. Immunofluorescence was much more entensive in submandibular salivary glands of cyclophosphamide-treated than control skunks. Similarly, virus was isolated from this tissue more consistently and at higher titer from principals than from controls. Immunofluorescence was extensive in brains of all skunks (both groups), but virus was isolated consistently only from brains of cyclophosphamide-treated skunks. Most of the cyclophosphamide-treated skunks had very few inflammatory cells in brain and cerebrospinal ganglia. Neuronal degeneration occurred in dorsal root ganglia of both principals and controls. The results suggest that the immune response has no effect on the development of rabies-induced aggressive behavior, that the immune response may inhibit salivary gland infection and that it is not essential for the development of neuronal degeneration in dorsal root ganglia.  相似文献   

17.
Male and female Sprague-Dawley rats were given CGS 21595, a pro-drug that is almost immediately metabolized to CGS 19213, a naphthoquinone that acts as a 5-lipoxygenase inhibitor. The compound was administered by gavage to five groups of Sprague-Dawley rats (group Nos. 1, 5, n = 30; group Nos. 2-4, n = 20) at daily doses of 0, 50, 150, 500, or 1,000 mg/kg for 13 weeks. Rats in the higher dose groups had a reduced weight gain, but significant neurologic signs were not observed. A peripheral neuropathy consisting predominantly of myelin destruction in the spinal nerve roots and sciatic nerves in male rats treated with greater than or equal to 150 mg/kg CGS 21595 and in female rats treated with greater than or equal to 50 mg/kg CGS 21595 for 13 weeks. This lesion was not fully reversible after a recovery period of 4 weeks. Lesions consisted of ballooning of myelin sheaths, infiltration by macrophages, demyelination, and occasional areas of remyelination. Axons were generally preserved, and the brain and spinal cord were not affected. Male and female rats in all treatment groups had cytoplasmic hyaline droplets in the proximal renal tubules. This change was reversible after 4 weeks and was not associated with any other adverse effects on the kidney.  相似文献   

18.
本研究旨在对萱草根素中毒家兔中枢神经系统进行病理学研究。从北黄花菜根中提取萱草根素，用1％的淀粉溶液配制成2％混悬液，试验组家兔每只每天灌服萱草根素混悬液4mL／kg，对照组灌服等量的1％淀粉溶液。于处理后第4、7、10、13、16、19天进行常规病理学检查。试验第4天大脑、小脑、脊髓和视神经中的神经纤维出现脱髓鞘变化，在小脑从白质中央向两侧进行性扩展，在脊髓从边缘向中央扩展，最终呈丝瓜络样变；第7天起，蒲肯野氏细胞和脊髓神经细胞发生固缩、坏死；第10天，大脑神经细胞出现坏死、凋亡，并且数目逐渐增多，出现噬神经现象，视网膜萎缩，节细胞固缩、溶解消失。超微结构观察显示，髓鞘变薄，板层崩解、断裂、分离，失去原来的致密结构；神经细胞染色体边集，线粒体肿胀、消失并空泡化、粗面内质网扩张，结构模糊。结果表明，萱草根素可引起神经纤维脱髓鞘和神经细胞的广泛性坏死，并最终导致家兔失明和死亡。  相似文献   

19.
Due to the therapeutic potential of gene therapy for neuronal injury, many studies of neurotrophic factors, vectors, and animal models have been performed. The presumed dog β-nerve growth factor (pdβ-NGF) was generated and cloned and its expression was confirmed in CHO cells. The recombinant pdβ-NGF protein reacted with a human β-NGF antibody and showed bioactivity in PC12 cells. The pdβ-NGF was shown to have similar bioactivity to the dog β-NGF. The recombinant pdβ-NGF plasmid was administrated into the intrathecal space in the gene therapy group. Twenty-four hours after the vector inoculation, the gene therapy group and the positive control group were intoxicated with excess pyridoxine for seven days. Each morning throughout the test period, the dogs'' body weight was taken and postural reaction assessments were made. Electrophysiological recordings were performed twice, once before the experiment and once after the test period. After the experimental period, histological analysis was performed. Dogs in the gene therapy group had no weight change and were normal in postural reaction assessments. Electrophysiological recordings were also normal for the gene therapy group. Histological analysis showed that neither the axons nor the myelin of the dorsal funiculus of L4 were severely damaged in the gene therapy group. In addition, the dorsal root ganglia of L4 and the peripheral nerves (sciatic nerve) did not experience severe degenerative changes in the gene therapy group. This study is the first to show the protective effect of NGF gene therapy in a dog model.  相似文献   

20.
Peripheral nerve sheath tumor was found in a 7-year-old male mongrel dog. The tumors were located in the right cheek subcutis and oral submucosa. Histologically, neoplastic cells were arranged in streaming bundles, occasionally interlacing bundles or whorls of elongated and spindle cells. Cellular atypia was poor and mitotic figures were rarely observed. Ultrastructurally, neoplastic cells had basement membrane, typical of Schwann cells. One bundle of normal peripheral nerve fibers and some myelinated axons were seen within the tumor tissues. Immunohistochemically, neoplastic cells reacted to vimentin, glial fibrillary acidic protein, S-100 protein and neuron specific enolase. In addition to the above immunoreactions, the included nerve fibers were positive for myelin basic protein and neurofilament protein. This paper also discusses immunohistochemical findings on differential diagnosis in comparison with those of canine hemangiopericytomas reported hitherto.  相似文献   

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