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排序方式: 共有2222条查询结果,搜索用时 312 毫秒
941.
Park KK Liu K Hu Y Smith PD Wang C Cai B Xu B Connolly L Kramvis I Sahin M He Z 《Science (New York, N.Y.)》2008,322(5903):963-966
The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathway, in adult retinal ganglion cells (RGCs) promotes robust axon regeneration after optic nerve injury. In wild-type adult mice, the mTOR activity was suppressed and new protein synthesis was impaired in axotomized RGCs, which may contribute to the regeneration failure. Reactivating this pathway by conditional knockout of tuberous sclerosis complex 1, another negative regulator of the mTOR pathway, also leads to axon regeneration. Thus, our results suggest the manipulation of intrinsic growth control pathways as a therapeutic approach to promote axon regeneration after CNS injury. 相似文献
942.
Lee JC Hwang IK Park SK Yoo KY Seo K Kang TC Oh YS Won MH 《Anatomia, histologia, embryologia》2005,34(4):252-257
This study was carried out to investigate the motor neurone degeneration in the ventral horn following transient spinal cord ischaemia at normothermic conditions in rabbits. Transient spinal cord ischaemia was induced by occlusion of the abdominal aorta underneath the left renal artery for 15 min at normothermia (38.7 degrees C). Sections at the level of L7 were examined using histochemical and electron microscopic methods. Cresyl violet-positive motor neurones began to reduce in number at 3 h after ischaemia reperfusion, and were not detectable at 48 h after ischaemia reperfusion. Acid fuchsin-positive motor neurones were detected at 1 h after ischaemia reperfusion, significantly increased up to 6 h after the ischaemia reperfusion, and eventually disappeared by 48 h after ischaemia reperfusion. In electron microscopic findings, the disintegration of cytoplasmic membranes, and the disruption of mitochondria and endoplasmic reticulum were observed in motor neurones at 30 min after ischaemia reperfusion. Motor neurones showed necrotic findings with pyknotic degeneration at 1 h after ischaemia reperfusion. The necrotic degeneration became severer time dependently after ischaemia reperfusion. At 48 h after ischaemia reperfusion, cellular components were not detectable in motor neurones. In conclusion, we suggest that the degeneration pattern of motor neurones of the ischaemic spinal cord was necrotic after ischaemia reperfusion under normothermic conditions. 相似文献
943.
Lee WS Lee GJ Lee GJ Yeo CD Kang JS Kim YH Kim SJ Kim JS Hwang SY Park JS Hwang JW Kang KS Lee YS Jeon KS Um CH Hong SI Kim YS 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(11):1335-1338
Toxicogenomics is now emerging as one of the most important genomic application because the toxicity test based on gene expression profiles is expected to be more precise and efficient than current histopathological approaches in a pre-clinical phase. One of the challenging issues in toxicogenomics is the construction of intelligent database management system which can deal with heterogeneous and complex data from many different experimental and information sources. TEST(Toxicogenomics for Efficient Safety Test) database is especially focused on the connectivity of heterogeneous data and the intelligent query system which enable users to obtain relevant useful information from the complex data sets. The database deals with four kinds of information; compound, histopathology, gene expression, and annotation information. Currently, TEST database maintains toxicogenomics information for 16 compounds, 45 microarrays, 190 animal experiments, and customized 4.8 K rat clone set. Our presented system is expected to be a good information source for studying of toxicology mechanism in the genome-wide level and can also be applied to the designing toxicity test chip. 相似文献
944.
Comparison of one-step RT-PCR and a nested PCR for the detection of canine distemper virus in clinical samples 总被引:3,自引:0,他引:3
Shin YJ Cho KO Cho HS Kang SK Kim HJ Kim YH Park HS Park NY 《Australian veterinary journal》2004,82(1-2):83-86
OBJECTIVE: To develop a rapid and sensitive method for the detection of canine distemper virus (CDV) by nested PCR using clinical specimens. DESIGN: A nested PCR was developed, compared to a one-step RT-PCR and validated. PROCEDURE: Two sets of specific primers for a one-step RT-PCR and a nested PCR, targeting a 640 bp fragment and a 297 bp fragment, respectively, were selected from the highly conserved region of the nucleocapsid protein (NP) gene of CDV. The nested PCR and the one-step RT-PCR were used to amplify a part of the CDV NP gene of a CDV vaccinal strain and samples of urine, blood, nasal discharge and saliva from 29 dogs suspected of suffering CD. RESULTS: Both the one-step RT-PCR and the nested PCR reacted with the CDV vaccinal strain, but not with canine parvovirus. The expected 640 bp fragment of the NP gene was detected in 11/22 (50.0%) blood, 10/20 (50.0%) urine, 5/25 (20.0%) saliva and 6/27 (22.2%) nasal swab samples by one-step RT-PCR, whereas the nested PCR amplified an expected 297 bp fragment of the NP gene in 18/22 (81.8%) blood, 15/20 (75.0%) urine, 14/25 (56%) saliva and 19/27 (70.3%) nasal swab samples. CONCLUSION: The nested PCR detected CDV in blood, urine, nasal swab and saliva more frequently than did the one-step RT-PCR. Therefore, this assay should be a useful aid to antemortem diagnosis of CDV infections in dogs. 相似文献
945.
946.
The vagus nerve is one route of transneural invasion for intranasally inoculated influenza a virus in mice 总被引:3,自引:0,他引:3
Matsuda K Park CH Sunden Y Kimura T Ochiai K Kida H Umemura T 《Veterinary pathology》2004,41(2):101-107
Intranasally inoculated neurotropic influenza viruses in mice infect not only the respiratory tract but also the central nervous system (CNS), mainly the brain stem. Previous studies suggested that the route of invasion of virus into the CNS was via the peripheral nervous system, especially the vagus nerve. To evaluate the transvagal transmission of the virus, we intranasally inoculated unilaterally vagectomized mice with a virulent influenza virus (strain 24a5b) and examined the distribution of the viral protein and genome by immunohistochemistry and in situ hybridization over time. An asymmetric distribution of viral antigens was observed between vagal (nodose) ganglia: viral antigen was detected in the vagal ganglion of the vagectomized side 2 days later than in the vagal ganglion of the intact side. The virus was apparently transported from the respiratory mucosa to the CNS directly and decussately via the vagus nerve and centrifugally to the vagal ganglion of the vagectomized side. The results of this study, thus, demonstrate that neurotropic influenza virus travels to the CNS mainly via the vagus nerve. 相似文献
947.
Bae JS Jang KH Park SC Jin HK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(1):111-114
The effects of topical administration of polysaccharides isolated from fungus, Phellinus gilvus (PG) on the healing of rat dermal wounds were assessed. In 10 Sprague-Dawley (SD) rats, six 6 mm diameter defects were made with a punch biopsy appliance. After 24 hr, test substances were applied to the defects twice a day: 0.025, 0.25, and 2.5% polysaccharides from PG (PG0.025, 0.25, and 2.5 groups), Madecassol ointment (MC group), aqueous gel (AG group) and no treatment (control group). Six days postoperatively, the contraction and reepithelialization of the wound surface were assessed. Wound diameter was significantly reduced in all PG groups (P<0.05). Complete epithelialization and macrophages were noted in the PG0.25 group, as compared to the control group. We conclude that polysaccharides isolated from PG have significant dermal wound healing effects, and this investigation suggests the potential clinical application of PG as a wound healing agent. 相似文献
948.
Jeong JH Kim GY Yoon SS Park SJ Kim YJ Sung CM Jang OJ Shin SS Koh HB Lee BJ Lee CY Kang MI Kim HJ Park NY Cho KO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(2):187-189
Although winter dysentery (WD) has been suspected to occur frequently in Korea, to date the exact epidemiology of WD has remained unknown. Therefore, we investigated the causative agents of WD by using electron microscopy, ELISA, RT-PCR, and nested PCR from 97 fecal samples of 32 WD-affected herds collected from 8 provinces during 2002-2004. The bovine coronavirus (BoCV) was consistently detected in all herds with WD. Of other pathogens, only coccidian oocyts were inconsistently but concurrently detected with BoCV. Ten isolates were identified as BoCV by immune electron microscope, immunofluorescent test and ELISA with antiserum to BoCV, and RT-PCR. From these results, it is concluded that WD caused by BoCV occurred in relatively high frequency and was widespread in Korea. The results provide important epidemiological data for the control and establishment of a surveillance system for WD in Korea. 相似文献
949.
Jeong WI Jeong DH Do SH Kim YK Park HY Kwon OD Kim TH Jeong KS 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(3):235-242
To date, the majority of research on hypercholesterolemia has focused on the effects of a high cholesterol diet on atherosclerosis and coronary heart disease. The toxic effects of cholesterol on the liver and the relationship between the intake of a high cholesterol diet and hepatic fibrosis, however, have not been investigated clearly or histopathologically. Male Wistar rats were fed a diet supplemented with 1.0% cholesterol and 0.3% sodium cholate for 12 weeks. Rats were sacrificed and analyzed via blood biochemistry, traditional microscopy and immunohistochemistry. Following the feeding of this diet, the rates of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and total cholesterol in the rats were elevated consistently from week 3 and throughout the remainder of the experiment. From microscopic observation, hepatic necrosis, macrophage infiltration and steatosis increased markedly throughout the experiment. Hepatic fibrosis and myofibroblast proliferation were detected at weeks 9 and 12. Mast cell appearance was proportional to the degree of hepatic damage. These findings suggest that hepatic fibrosis is inducible by a high cholesterol diet and is likely the result of the interaction between several different cell types (i.e., macrophages, myofibroblasts, and mast cells) in an inflammatory milieu. Hypercholesterolemia should be considered as a risk factor for hepatic fibrosis as well as atherosclerosis and coronary artery disease. 相似文献
950.
Role of gap junctional intercellular communication (GJIC) through p38 and ERK1/2 pathway in the differentiation of rat neuronal stem cells 总被引:4,自引:0,他引:4
Yang SR Cho SD Ahn NS Jung JW Park JS Jo EH Hwang JW Jung JY Kim TY Yoon BS Lee BH Kang KS Lee YS 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(3):291-294
Gap junctional intercellular communications (GJIC) contributes to neural function in development and differentiation of CNS. In this study, we have investigated the expression of GJIC during the differentiation of neuronal stem cells and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neuronal stem cell-derived cells from rat brain. During neuronal stem cell differentiation, expressions of Cx43 and 32 were increased for the duration of 72 hr, however the effect were decreased on the 7d. In the neuronal stem cell-derived cells, pretreatments with p38 MAP kinase inhibitor, SB203580, and MEK inhibitor, PD98059, could protect GJIC against TPA-induced inhibition of GJIC. Our data suggest that GJIC plays an important role during neuronal stem cell differentiation, and ERK1/2 and p38 MAP kinase signaling pathway may be closely related functionally to regulate gap junction in rat neuronal stem cell-derived cells. 相似文献