Background： Single-fiber electromyography （SFEMG） has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis （ALS） by the revised El Escorial criteria....Background： Single-fiber electromyography （SFEMG） has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis （ALS） by the revised El Escorial criteria. Although concentric needle （CN） electrodes have been used to assess jitter in myasthenia gravis patients and healthy controls, there are few reports using CN electrodes to assess motor unit instability and denervation in neurogenic diseases. The aim of this study was to determine whether quantitative changes in jitter and spike number using CN electrodes could be used for ALS studies. Methods： Twenty-seven healthy controls and 23 ALS patients were studied using both CN and single-fiber needle （SFN） electrodes on the extensor digitorum communis muscle with an SFEMG program. The SFN-jitter and SFN-fiber density data were measured using SFN electrodes. The CN-jitter and spike number were measured using CN electrodes. Results： The mean CN-j itter was significantly increased in ALS patients （47.3 ±17.0 μs） than in healthy controls （27.4 ± 3.3 las） （P 〈 0.001 ）. Besides, the mean spike number was significantly increased in ALS patients （2.5 ± 0.5） than in healthy controls （1.7 ± 0.3） （P 〈 0.001）. The sensitivity and specificity in the diagnosis of ALS were 82.6% and 92.6% for CN-jitter （cut-offvalue： 32 gs）, and 91.3% and 96.3% for the spike number （cut-off value： 2.0）, respectively. There was no significant difference between the SFN-jitter and CN-jitter in ALS patients; meanwhile, there was no significant difference between the SFN-jitter and CN-jitter in healthy controls. Conclusion： CN-jitter and spike number could be used to quantitatively evaluate changes due to denervation-reinnervation in ALS.展开更多
Background Single-fiber electromyography is the most sensitive neurophysiological test for the diagnosis of myasthenia gravis （MG）,but its use is limited by the potential risk of transmission of infections.Jitter an...Background Single-fiber electromyography is the most sensitive neurophysiological test for the diagnosis of myasthenia gravis （MG）,but its use is limited by the potential risk of transmission of infections.Jitter analysis with disposable concentric needle electrodes （CNEs） is therefore being investigated.This pilot study aimed to evaluate jitter analysis with CNEs for the diagnosis of MG.Methods Forty-two healthy Chinese volunteers and 44 MG patients were prospectively enrolled.MG patients were classified according to the Osserman classification,and acetylcholine receptor antibody titer was measured.Jitter analysis with CNEs in the extensor digitorum communis and repetitive nerve stimulation （RNS） testing were performed.Jitter was expressed as the mean consecutive difference （MCD）,and 20 action potential pairs were analyzed in each subject.The mean MCD in each subject and the mean individual MCD of all action potential pairs were compared between groups.Results The mean MCD and mean individual MCD were higher in MG patients （（42.3±20.0） μs and （42.2±26.0） μs） than in healthy volunteers （（23.0±3.1） μs and （22.8±7.5） μs）.The area under the receiver operating characteristic curve for the mean MCD of MG patients and healthy volunteers combined was 0.85.The mean MCD and mean individual MCDwere higher in generalized MG patients （（64.1±18.5） μs and （63.6±30.0） μs） than in ocular MG patients （（33.1±12.0） μs and （33.2±17.6） μs）,and were higher in MG patients with abnormal RNS results （（57.2±18.3） μs and （57.3±29.2） μs） than in MG patients with normal RNS results （（32.9±14.8） μs and （32.7±18.3） μs）.Abnormal RNS results were observed in 38.60% （17/44） of MG patients and abnormal jitter were observed in 72.70% （32/44） of MG patients.Conclusion Jitter analysis with CNEs is feasible for the diagnosis of MG.展开更多
通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋...通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋落物分解有不同程度的促进作用.经过153 d的分解后,未经处理的杉木针叶干质量损失率为20.49%,与林下植物叶混合的凋落物干质量损失率为43.67%,其促进作用最大;外加4 gNaNO3的促进作用次之,凋落物干质量损失率为42.07%;外加2 g NaNO3的凋落物干质量损失率为29.13%.对分解过程中各试验方案的凋落物干质量保留率进行方差分析,在开始的62 d内,与林下植被叶混合的杉木针叶凋落物分解速率和其他3种处理之间的差异显著,62 d后未经处理的杉木针叶与加2 g NaNO3的凋落物的分解速率没有显著差异,它们与加4 g NaNO3或林下植物叶的凋落物的分解速率差异显著.凋落物分解速率与凋落物初始C:N比值存在显著的线性关系.外加N源和与林下植物叶混合后,凋落物N的含量增加0.6～1.6倍,C:N比值下降0.4～0.6倍,凋落物底物质量提高,分解速率增大.分解过程中,C质量不断下降,损失24.7%～47.4%,杉木针叶中N出现富集作用,外加N源和与林下植物叶混合的凋落物N释放一定数量后保持稳定的状态.可见,外加适量N源和与林下植物叶混合能提高凋落物底物质量,促进凋落物分解和养分的释放,对维持杉木林的土壤肥力有着重要作用.展开更多
文摘Background： Single-fiber electromyography （SFEMG） has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis （ALS） by the revised El Escorial criteria. Although concentric needle （CN） electrodes have been used to assess jitter in myasthenia gravis patients and healthy controls, there are few reports using CN electrodes to assess motor unit instability and denervation in neurogenic diseases. The aim of this study was to determine whether quantitative changes in jitter and spike number using CN electrodes could be used for ALS studies. Methods： Twenty-seven healthy controls and 23 ALS patients were studied using both CN and single-fiber needle （SFN） electrodes on the extensor digitorum communis muscle with an SFEMG program. The SFN-jitter and SFN-fiber density data were measured using SFN electrodes. The CN-jitter and spike number were measured using CN electrodes. Results： The mean CN-j itter was significantly increased in ALS patients （47.3 ±17.0 μs） than in healthy controls （27.4 ± 3.3 las） （P 〈 0.001 ）. Besides, the mean spike number was significantly increased in ALS patients （2.5 ± 0.5） than in healthy controls （1.7 ± 0.3） （P 〈 0.001）. The sensitivity and specificity in the diagnosis of ALS were 82.6% and 92.6% for CN-jitter （cut-offvalue： 32 gs）, and 91.3% and 96.3% for the spike number （cut-off value： 2.0）, respectively. There was no significant difference between the SFN-jitter and CN-jitter in ALS patients; meanwhile, there was no significant difference between the SFN-jitter and CN-jitter in healthy controls. Conclusion： CN-jitter and spike number could be used to quantitatively evaluate changes due to denervation-reinnervation in ALS.
文摘Background Single-fiber electromyography is the most sensitive neurophysiological test for the diagnosis of myasthenia gravis （MG）,but its use is limited by the potential risk of transmission of infections.Jitter analysis with disposable concentric needle electrodes （CNEs） is therefore being investigated.This pilot study aimed to evaluate jitter analysis with CNEs for the diagnosis of MG.Methods Forty-two healthy Chinese volunteers and 44 MG patients were prospectively enrolled.MG patients were classified according to the Osserman classification,and acetylcholine receptor antibody titer was measured.Jitter analysis with CNEs in the extensor digitorum communis and repetitive nerve stimulation （RNS） testing were performed.Jitter was expressed as the mean consecutive difference （MCD）,and 20 action potential pairs were analyzed in each subject.The mean MCD in each subject and the mean individual MCD of all action potential pairs were compared between groups.Results The mean MCD and mean individual MCD were higher in MG patients （（42.3±20.0） μs and （42.2±26.0） μs） than in healthy volunteers （（23.0±3.1） μs and （22.8±7.5） μs）.The area under the receiver operating characteristic curve for the mean MCD of MG patients and healthy volunteers combined was 0.85.The mean MCD and mean individual MCDwere higher in generalized MG patients （（64.1±18.5） μs and （63.6±30.0） μs） than in ocular MG patients （（33.1±12.0） μs and （33.2±17.6） μs）,and were higher in MG patients with abnormal RNS results （（57.2±18.3） μs and （57.3±29.2） μs） than in MG patients with normal RNS results （（32.9±14.8） μs and （32.7±18.3） μs）.Abnormal RNS results were observed in 38.60% （17/44） of MG patients and abnormal jitter were observed in 72.70% （32/44） of MG patients.Conclusion Jitter analysis with CNEs is feasible for the diagnosis of MG.
文摘通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋落物分解有不同程度的促进作用.经过153 d的分解后,未经处理的杉木针叶干质量损失率为20.49%,与林下植物叶混合的凋落物干质量损失率为43.67%,其促进作用最大;外加4 gNaNO3的促进作用次之,凋落物干质量损失率为42.07%;外加2 g NaNO3的凋落物干质量损失率为29.13%.对分解过程中各试验方案的凋落物干质量保留率进行方差分析,在开始的62 d内,与林下植被叶混合的杉木针叶凋落物分解速率和其他3种处理之间的差异显著,62 d后未经处理的杉木针叶与加2 g NaNO3的凋落物的分解速率没有显著差异,它们与加4 g NaNO3或林下植物叶的凋落物的分解速率差异显著.凋落物分解速率与凋落物初始C:N比值存在显著的线性关系.外加N源和与林下植物叶混合后,凋落物N的含量增加0.6～1.6倍,C:N比值下降0.4～0.6倍,凋落物底物质量提高,分解速率增大.分解过程中,C质量不断下降,损失24.7%～47.4%,杉木针叶中N出现富集作用,外加N源和与林下植物叶混合的凋落物N释放一定数量后保持稳定的状态.可见,外加适量N源和与林下植物叶混合能提高凋落物底物质量,促进凋落物分解和养分的释放,对维持杉木林的土壤肥力有着重要作用.
