目的对荧光聚合酶链式反应(PCR)体系检测B族链球菌(group B Streptococcus,GBS)的精密度、准确性和检测限进行验证。方法取1例GBS-DNA为阳性的临床样本重复扩增10次,以验证精密度;扩增20例结果已知的临床样本,将结果与实际结果比对,以...目的对荧光聚合酶链式反应(PCR)体系检测B族链球菌(group B Streptococcus,GBS)的精密度、准确性和检测限进行验证。方法取1例GBS-DNA为阳性的临床样本重复扩增10次,以验证精密度;扩增20例结果已知的临床样本,将结果与实际结果比对,以验证准确性;将阳性对照参考品稀释至10^4CFU/mL,重复扩增10次以验证检测限。结果重复扩增10次的检测结果均为阳性,且所有通道的CT值变异系数CV<5%;20例标本的检测结果比对完全相符,符合率为100%;稀释到检测限的10次重复实验结果均为阳性。结论荧光PCR体系检测GBS结果稳定、可靠,适用于医学实验室对GBS的检测。展开更多
Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly...Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly（L-lactic-co-glycolic acid） （PLGA） scaffolds and, when cografted with Schwann cells （SCs）, could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function. Methods NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student＇s t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance （ANOVA） was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials （CMEPs） and Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） score. The X2 test was used to determine the differences in recovery percentage of CMEPs. Results NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs （（1.7831±0.0402）% vs. （1.4911±0.0313）%, P 〈0.001）. Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA＋NSCs＋SCs group was more than that in PLGA＋NSCs group and in PLGA group （（110.25±30.46） vs. （18.25±3.30） and （11.25±5.54）, P 〈0.01）. The percentage of CMEPs recovery in PLGA＋NSCs＋SCs group was higher than in the other groups （84.8% vs, 50.0% and 37.5%, P 〈0.05）. The amplitude of CMEPs in PLGA＋NSCs＋SCs group was higher than in the other groups （（1452.63±331.70） IJV vs. （428.84±193.01） IJV and （117.33±14.40） μV, P 〈0.05）. Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function. Conclusions NSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.展开更多
文摘目的对荧光聚合酶链式反应(PCR)体系检测B族链球菌(group B Streptococcus,GBS)的精密度、准确性和检测限进行验证。方法取1例GBS-DNA为阳性的临床样本重复扩增10次,以验证精密度;扩增20例结果已知的临床样本,将结果与实际结果比对,以验证准确性;将阳性对照参考品稀释至10^4CFU/mL,重复扩增10次以验证检测限。结果重复扩增10次的检测结果均为阳性,且所有通道的CT值变异系数CV<5%;20例标本的检测结果比对完全相符,符合率为100%;稀释到检测限的10次重复实验结果均为阳性。结论荧光PCR体系检测GBS结果稳定、可靠,适用于医学实验室对GBS的检测。
基金This work was supported by the grant from the International Cooperation Research Foundation of National Natural Science Foundation of China （No. 30540450581）. Conflict of interest： none.
文摘Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly（L-lactic-co-glycolic acid） （PLGA） scaffolds and, when cografted with Schwann cells （SCs）, could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function. Methods NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student＇s t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance （ANOVA） was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials （CMEPs） and Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） score. The X2 test was used to determine the differences in recovery percentage of CMEPs. Results NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs （（1.7831±0.0402）% vs. （1.4911±0.0313）%, P 〈0.001）. Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA＋NSCs＋SCs group was more than that in PLGA＋NSCs group and in PLGA group （（110.25±30.46） vs. （18.25±3.30） and （11.25±5.54）, P 〈0.01）. The percentage of CMEPs recovery in PLGA＋NSCs＋SCs group was higher than in the other groups （84.8% vs, 50.0% and 37.5%, P 〈0.05）. The amplitude of CMEPs in PLGA＋NSCs＋SCs group was higher than in the other groups （（1452.63±331.70） IJV vs. （428.84±193.01） IJV and （117.33±14.40） μV, P 〈0.05）. Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function. Conclusions NSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.
