Long term assessment of axonal regeneration through polyimide regenerative electrodes to interface the peripheral nerve

Biomaterials ◽  
2005 ◽  
Vol 26 (14) ◽  
pp. 2021-2031 ◽  
Author(s):  
Natalia Lago ◽  
Dolores Ceballos ◽  
Francisco J Rodrı́guez ◽  
Thomas Stieglitz ◽  
Xavier Navarro
Author(s):  
Dina V. Rusanova ◽  
Oleg L. Lakhman ◽  
Galina M. Bodienkova ◽  
Irina V. Kudaeva ◽  
Natalya G. Kuptsova

Introduction. There is a lack of knowledge of the pathophysiological mechanisms that form peripheral nerve disorders in mercury lesions of professional origin. The study aims to reveal the mechanisms underlying peripheral nerve damage in the long-term post-contact period of chronic mercury intoxication (CMI). Materials and methods. Fifty-one people had the diagnosis of a long-term period of CMI. The post-contact period was 8.5±2.6 years. The authors compared the results with a control group of 26 healthy men who had no contact with toxic substances. Stimulating electroneuromyography was performed. We studied the body systems that could contribute to the formation of disorders in the peripheral nerves. Changes in peripheral hemodynamics were studied using reovasography. The content of autoantibodies, neuron-specific enolase, serotonin, histamine, catecholamines (epinephrine, dopamine), metanephrine, and neurotrophin-3 was reviewed. The content of ceruloplasmin, secondary products of lipid peroxidation processes, reduced glutathione, the activity of superoxide dismutase and the content of nitric oxide levels were determined. Results. The study established pathogenetic structural links of peripheral nerve disorders. The autoimmune process's role was to increase the range of antibodies to the MAG protein and increase the level of antibodies to DNA. Violations of elastic-tonic properties of peripheral vessels could be associated with the functional state of motor axons. The increased content of neurotransmitters is related to the state of peripheral blood circulation; the most pronounced changes were on the legs, which could contribute to the occurrence and maintenance of vasoconstriction. The role of oxidative stress in the formation of demyelinating disorders in patients' peripheral nerves in the long-term period of CRI is possible. Conclusion. Neuroimmunological processes has an essential role in the development of peripheral nerve demyelination was shown, which consists in an increase in the content of antibodies to the MAG protein expressed on Schwann cells of peripheral nerves and in an increase in the level of antibodies to DNA involved in the formation of demyelinating changes when exposed to metallic mercury. The revealed pathological changes in the state of the peripheral blood circulation, characterized by a violation of the vessels' elastic-tonic properties, leading to demyelination of motor axons in patients in the long-term period of CMI. The increased content of neurotransmitters in the examined is of great importance in the state of peripheral circulation. Pronounced changes in blood circulation are established on the lower extremities, which may be associated with the predominance of α-adrenergic receptors in the arterial bed and may contribute to the occurrence and maintenance of vasoconstriction in the legs. The relationship between changes in indicators of oxidative stress, consisting of a decrease in the value of superoxide dismutase and reduced glutathione, and the formation of demyelinating disorders of peripheral nerves in patients in the long-term period of CMI has been proved.


2018 ◽  
Vol 129 (3) ◽  
pp. 805-814 ◽  
Author(s):  
Eric D. Young ◽  
Davis Ingram ◽  
William Metcalf-Doetsch ◽  
Dilshad Khan ◽  
Ghadah Al Sannaa ◽  
...  

OBJECTIVEWhile sporadic peripheral schwannomas (SPSs) are generally well treated with surgery, their biology is not well understood. Consequently, treatment options are limited. The aim of this study was to provide a comprehensive description of SPS. The authors describe clinicopathological features and treatment outcomes of patients harboring these tumors, and they assess expression of biomarkers using a clinically annotated tissue microarray. Together, these data give new insight into the biology and management of SPS.METHODSPatients presenting with a primary SPS between 1993 and 2011 (n = 291) were selected from an institutional registry to construct a clinical database. All patients underwent follow-up, and short- and long-term outcomes were assessed. Expression of relevant biomarkers was assessed using a new tissue microarray (n = 121).RESULTSSPSs were generally large (mean 5.5 cm) and frequently painful at presentation (55%). Most patients were treated with surgery (80%), the majority of whom experienced complete resolution (52%) or improvement (18%) of their symptoms. Tumors that were completely resected (85%) did not recur. Some patients experienced short-term (16%) and long-term (4%) complications postoperatively. Schwannomas expressed higher levels of platelet-derived growth factor receptor–β (2.1) than malignant peripheral nerve sheath tumors (MPNSTs) (1.5, p = 0.004) and neurofibromas (1.33, p = 0.007). Expression of human epidermal growth factor receptor–2 was greater in SPSs (0.91) than in MPNSTs (0.33, p = 0.002) and neurofibromas (0.33, p = 0.026). Epidermal growth factor receptor was expressed in far fewer SPS cells (10%) than in MPNSTs (58%, p < 0.0001) or neurofibromas (37%, p = 0.007). SPSs more frequently expressed cytoplasmic survivin (66% of tumor cells) than normal nerve (46% of cells), but SPS expressed nuclear survivin in fewer tumor cells than in MPNSTs (24% and 50%, respectively; p = 0.018).CONCLUSIONSComplete resection is curative for SPS. Left untreated, however, these tumors can cause significant morbidity, and not all patients are candidates for resection. SPSs express a pattern of biomarkers consistent with the dysregulation of the tumor suppressor merlin observed in neurofibromatosis Type 2–associated schwannomas, suggesting a shared etiology. This SPS pattern is distinct from that of other tumors of the peripheral nerve sheath.


2001 ◽  
Vol 10 (3) ◽  
pp. 139-145 ◽  
Author(s):  
JG Foster ◽  
SK Kish ◽  
CH Keenan

BACKGROUND: Recommendations on use of neuromuscular blocking agents include using peripheral nerve stimulators to monitor depth of blockade and concomitantly administering sedatives and/or analgesics. OBJECTIVE: To evaluate critical care nurses' practices in administering neuromuscular blocking agents. METHODS: A 16-item survey was mailed to 483 acute care facilities in the United States. Of these, 246 surveys (51%) were returned and analyzed to determine use of neuromuscular blocking agents, peripheral nerve stimulators, sedatives, and analgesics. Logistic regression analysis was used to find independent predictors of use of peripheral nerve stimulators. RESULTS: Seventy-five percent of respondents reported long-term use of neuromuscular blocking agents in critically ill patients. Of those, 63% monitored the level of blockade with peripheral nerve stimulators. Reasons for not using peripheral nerve stimulators included unavailability of equipment (48%), lack of training (36%), and insufficient evidence that peripheral nerve stimulators improve care (23%). Predictors of use of stimulators were facilities with more than 150 beds (P &lt; .001) and administration of neuromuscular blocking agents by continuous infusion (P &lt; .001). Ninety-five percent of respondents reported using concurrent analgesics/sedatives always or most of the time. Facilities with fewer than 10 beds in the intensive care unit used concurrent analgesics/sedatives significantly less often than did facilities with 10 beds or more (90% vs 98%, respectively; P = .03). CONCLUSIONS: Small and large facilities differ in concomitant use of analgesics/sedatives and peripheral nerve stimulators. Education and research are needed to ensure that patients receive adequate monitoring and sedation during administration of neuromuscular blocking agents.


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