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71.

Background

Previous studies suggest that dexmedetomidine has a protective effect against local anaesthetic-induced nerve injury in regional nerve blocks. Whether this potentially protective effect exists in the context of diabetes mellitus is unknown.

Methods

A diabetic state was established in adult male Sprague–Dawley rats with intraperitoneal injection of streptozotocin. Injections of ropivacaine 0.5%, dexmedetomidine 20 μg kg?1 (alone and in combination), or normal saline (all in 0.2 ml) were made around the sciatic nerve in control and diabetic rats (n=8 per group). The duration of sensory and motor nerve block and the motor nerve conduction velocity (MNCV) were determined. Sciatic nerves were harvested at post-injection day 7 and assessed with light and electron microscopy or used for pro-inflammatory cytokine measurements.

Results

Ropivacaine and dexmedetomidine alone or in combination did not produce nerve fibre damage in control non-diabetic rats. In diabetic rats, ropivacaine induced significant nerve fibre damage, which was enhanced by dexmedetomidine. This manifested with slowed MNCV, decreased axon density, and decreased ratio of inner to outer diameter of the myelin sheath (G ratio). Demyelination, axon disappearance, and empty vacuoles were also found using electron microscopy. An associated increase in nerve interleukin-1β and tumour necrosis factor-α was also seen.

Conclusions

Ropivacaine 0.5% causes significant sciatic nerve injury in diabetic rats that is greatly potentiated by high-dose dexmedetomidine. Although the dose of dexmedetomidine used in this study is considerably higher than that used in clinical practice, our data suggest that further studies to assess ropivacaine (alone and in combination with dexmedetomidine) use for peripheral nerve blockade in diabetic patients are warranted.  相似文献   
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为探讨用腺病毒载体携带PML(PromyelocyticLeukemia)基因作为前列腺癌基因治疗的可能性,应用重组人携带PML基因腺病毒(AdPML)感染培养的前列腺癌细胞,观察表达PML蛋白的癌细胞与对照组癌细胞的体外生长和裸鼠体内致瘤能力变化,对荷瘤裸鼠瘤体周围注射AdPML,观察治疗组和对照组肿瘤生长的变化。结果显示,感染AdPML的前列腺癌细胞体外生长和裸鼠体内致瘤能力明显下降,荷瘤裸鼠瘤体周围注射AdPML后肿瘤生长速度明显减慢。证实了PML是一种生长抑制因子,提示其可能被应用于前列腺癌的基因治疗研究  相似文献   
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Creutzfeldt-Jakob disease (CJD), Gerstmann-Str?ussler-Scheinker syndrome (GSS), fatal familial insomnia (FFI) and kuru constitute major human prion disease phenotypes. Each has been successfully transmitted in animal models and all are invariably fatal neurodegenerative disorders, with the brains of affected individuals harbouring variable amounts of an abnormal, protease-resistant form of the prion protein (PrPres), which is inextricably linked to pathogenesis and transmissibility. Classical sporadic CJD is the most common human transmissible spongiform encephalopathy (TSE), but recently the variant form (vCJD), first described in the UK in 1996, has drawn considerable attention. In contrast to sporadic CJD, FFI and GSS are almost invariably genetically determined TSEs, caused by a range of mutations within the open reading frame of the prion protein gene (PRNP) on chromosome 20. By definition, the nosologic term FFI is reserved for patients manifesting prominent insomnia, generally in combination with dysautonomia, myoclonus, and eventual dementia, with the predominant pathologic changes lying within the thalami and a specific underlying mutation in PRNP. GSS, however, encompasses a more diverse clinical spectrum ranging from progressive cerebellar ataxia or spastic paraparesis (both usually in combination with dementia), to isolated cognitive impairment resembling Alzheimer's disease. Additional extra-pyramidal features, which may respond to dopaminergic therapy can also be seen. Neuropathological findings are also relatively diverse, partly overlapping with those found in Alzheimer's disease, especially the presence of neurofibrillary tangles (NFTs). Although GSS and FFI in their classical forms are differentiable clinical profiles, such divisions may have no intrinsic biological validity given the considerable intra-familial clinico-pathological diversity so commonly seen. Kuru constitutes a horizontally transmitted prion disease, which after a lengthy incubation period, presents clinically as a progressive cerebellar ataxia associated with tremors. It has now almost disappeared since the cessation of ritualistic endocannibalism in the late 1950s but was previously exclusively endemic amongst the Fore linguistic group and neighbouring tribes in the Eastern Highlands of New Guinea. Uniform topographical central nervous system histopathology includes spongiform change and neuronal loss, with amyloid (kuru) plaques in approximately 75% of cases.  相似文献   
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