The mechanism of the actions of oxaliplatin on ion currents and action potentials in differentiated NG108-15 neuronal cells

Oxaliplatin (OXAL) is a platinum-based chemotherapeutic agent which is effective against advanced or metastatic gastrointestinal cancer. However, the mechanisms responsible for the development of the neuropathy induced by this agent remain unclear. In this study, we attempted to evaluate the possible effects of OXAL on ion currents and action potentials (APs) in NG108-15 cells differentiated with dibutyryl cyclic-AMP. Application of OXAL decreased the peak amplitude of voltage-gated Na⁺ current (I_Na) with no change in the overall current–voltage relations of the currents. This agent also produced a concentration-dependent slowing of I_Na inactivation. A further application of ranolazine reversed OXAL-induced slowing of I_Na inactivation. Unlike ranolazine or riluzole, OXAL had no effect on persistent I_Na elicited by long ramp pulses. OXAL (100 μM) also had little or no effect on the peak amplitude of L-type Ca²⁺ currents in NG108-15 cells, while it suppressed delayed-rectifier K⁺ current. In current-clamp recordings, OXAL alone reduced the amplitude of APs; however, it did not alter the duration of APs. However, after application of tefluthrin, OXAL did increase the duration of APs. Moreover, OXAL decreased the peak amplitude of I_Na with a concomitant reduction of current inactivation in HEK293T cells expressing SCN5A. The effects of OXAL on ion currents presented here may contribute to its neurotoxic actions in vivo.     

儿童肾上腺肿瘤104例临床分析

目的分析儿童肾上腺肿瘤的临床特征,提高对儿童肾上腺肿瘤诊断和处理的认识。方法回顾分析1991—2002年12年间中山大学附属第一医院收治的104例儿童肾上腺肿瘤的临床特点、诊断和病理的关系。结果发病年龄0～14岁,男63例,女41例。神经母细胞瘤75例;肾上腺皮质肿瘤22例,其中癌及腺瘤各11例;嗜铬细胞瘤2例;其他5例。神经母细胞瘤患儿以发热、腹痛、腹部包块为主要表现,尿香草杏仁酸(VMA)可不升高;肾上腺皮质肿瘤患儿中外周性性早熟的临床及内分泌激素改变多于库欣综合征表现。血乳酸脱氢酶(LDH)水平对鉴别良/恶性肿瘤有提示意义。结论儿童肾上腺肿瘤以神经母细胞瘤及肾上腺皮质肿瘤最为常见,临床表现异于成人,应结合临床及影像学特征综合诊断。     

儿童神经母细胞性肿瘤的临床特征及预后分析的单中心研究

目的 分析儿童神经母细胞性肿瘤(NT)的临床特征及预后情况,探讨NT预后相关危险因素.方法 选择2010年1月至2016年6月,于四川大学华西第二医院儿童血液肿瘤科收治的34例新发儿童NT患儿的临床病例资料为研究对象.对收集的34例新发儿童NT患儿的一般临床资料、辅助检查结果、肿瘤原发及转移部位、病理分型、MYCN基因扩增检测结果、临床分期与危险度分组、疗效及预后等情况进行回顾性分析.采用Kaplan-Meier法计算本研究34例儿童NT患儿的2年无事件生存(EFS)率和总体生存(OS)率,采用对数秩检验(log-rank test)单因素分析影响其预后的影响因素,并采用Cox比例风险回归模型分析儿童NT预后的独立影响因素.本研究遵循的程序符合四川大学华西第二医院人体试验委员会所制定的伦理学标准,得到该委员会批准.结果 ①本研究34例儿童NT患儿中,男性患儿为13例(38.2％),女性为21例(61.8％);中位发病年龄为40.5个月,发病年龄＞18个月患儿为28例(82.4％);腹部包块(50.0％,17/34),发热(32.3％,11/34)和腹部疼痛(32.3％,11/34)是儿童NT最常见的就诊原因.②本研究34例儿童NT患儿中,原发于腹部患儿为28例(82.4％),原发于非腹部患儿为6例(17.6％);初诊时骨髓转移患儿为16例(47.0％),骨骼转移患儿为10例(29.4％),颈部淋巴结转移(原发于纵隔)患儿为3例(8.8％),脾、肺转移患儿各为1例(2.9％).③血常规检查结果显示,贫血患儿为18例(52.9％);17例儿童NT患儿行血清神经元特异性烯醇化酶(NSE)检测,其血清NSE水平为27.28～370.00 ng/mL.④本研究34例儿童NT患儿中,14例(41.2％)患儿的肿瘤最大直径＞9 cm;影像学检查结果显示,肾上腺区包块患儿为18例(52.9％),腹膜后包块患儿为10例(29.4％),纵隔、颈部和盆腔包块患儿分别为4例(11.8％)、1例(2.9％)和1例(2.9％).⑤病理分型:本研究34例儿童NT患儿中,神经母细胞瘤(NB)患儿为24例(70.6％),节细胞性神经母细胞瘤(GNB)患儿为10例(29.4％).⑥本研究接受MYCN基因扩增检测的30例儿童NT患儿中,MYCN扩增患儿为11例(36.7％,均为Ⅲ～Ⅳ期和高/极高危组),未扩增患儿为19例(63.3％).⑦临床分期:本研究34例儿童NT患儿中,Ⅰ～Ⅳ期的儿童NT患儿分别为2例(5.9％)、4例(11.8％)、10例(29.4％)和18例(52.9％);低、中、高、极高危组患儿分别为3例(8.8％)、6例(17.6％)、10例(29.4％)和15例(44.1％).⑧本研究34例儿童NT患儿中,化疗前接受手术治疗患儿为28例(82.4％),术前化疗3～4个疗程后再行延期手术切除肿瘤患儿为6例(17.6％);本研究儿童NT患儿的2年EFS率为50.0％,2年OS率为67.6％.⑨Ⅲ～Ⅳ期儿童NT、化疗前肿瘤未/不全切除、MYCN扩增、高/极高危组NT分别与Ⅰ～Ⅱ期儿童NT、化疗前肿瘤完全切除、无MYCN扩增及低/中危组的2年EFS率分别比较,差异均有统计学意义(x2=7.697、6.048、5.695、5.125,P=0.006、0.014、0.015、0.025).⑩影响儿童NT预后相关因素的多因素分析结果显示,化疗前肿瘤手术切除程度(OR=3.668,95％CI=1.209～11.133,P=0.022)和危险度分组(OR=46.340,95％CI=2.764～777.065,P=0.008)是儿童NT的独立不良预后因素.结论 儿童NT发病年龄小,初诊时常已为进展期NT,并易于早期发生多部位、多灶性转移.MYCN扩增是儿童NT的不良分子生物学预后因素,多见于进展期和高/极高危患儿,其也是划分患儿危险度分组的重要指标.高/极高危儿童NT患儿病死率高、预后差.     

神经母细胞瘤57例临床分析

目的：讨论小儿神经母细胞瘤（NB）诊断、治疗与预后特点。方法：分析1994－1999年间收治小儿NB57例，以骨髓细胞形态学、X线、B超、CT及病理检查确诊。结果：57例男性39例，女性18例，各年龄段均可发病，5岁以下尤甚。临床以不规则发热、贫血、腹痛、腹部肿块为主要表现。NB好发于腹部，其次为后纵隔。确诊后49例予Apec方案化疗，其后手术。结论：骨髓细胞形态学和X线检查是诊断X线检查是诊断NB的较好方法，B超、CT可提高肿瘤检出率。NB经确诊首次化疗效果明显，其后延期手术。血清LDH明显增高化疗敏感性差，提示预后差。     

Hepatoblastoma presenting with focal nodular hyperplasia after treatment of neuroblastoma

Focal nodular hyperplasia (FNH) is a benign, poorly understood hepatic tumor that is rare in children. Although there is no evidence for malignant degeneration, FNH can occur adjacent to a malignancy. Here, the case of a 4-year-old boy with a hepatic mass and history of stage IV neuroblastoma is presented. Initial imaging and core-needle biopsy were consistent with FNH. However, after left lateral segmentectomy, pathologic examination revealed a malignant tumor most consistent with small cell undifferentiated hepatoblastoma as well as 3 foci of FNH in the surrounding parenchyma.     

Differentiated neuroblastoma cells are more susceptible to aluminium toxicity than developing cells

The influence of aluminium (20–50 μg/ml) on neuronal function was examined using electrophysiological techniques and neuroblastoma clone cells which offer a convenient model of differentiating and fully active neurons. Two specific questions were addressed: 1) Can differentiated cells maintain their normal excitable function when exposed to aluminium? 2) Can proper development of electrophysiological properties be achieved in its presence? We report that aluminium caused premature onset of deterioration in fully differentiated cells. Within 4–6 days they depolarized from ?29.3+-0.9 mV to levels lower than ?15 mV; compound polyphasic action potentials were gradually replaced by slow monophasic spikes before the final loss of excitable properties and structural deformations was noticed. Developing cells followed the normal pattern of differentiation in the presence of aluminium: within 7 days they extended neurites, hyperpolarized and exhibited polyphasic spikes. These results show that neuroblastoma cells are apparently less susceptible to aluminium's toxicity during the process of development than after differentiation. Possible mechanisms by which aluminium may exert its effects are discussed in view of these observations.     

Morphological and Cytogenetic Characterization and N-myc Oncogene Analysis of a Newly Established Neuroblastoma Cell Line

A permanent cell line established from a xenograft of neuroblastoma which occurred in a 5 year old girl was investigated for its morphological and biological characteristics. The cultured cells were tumorigenic in nude mice. Microscopically, each tumor consisted of small round to polygonal cells with irregular nuclei and prominent nucleoli, corresponding to the features of the primary and xenografted tumor cells. Electron microscopic examination revealed that both the transplanted tumor cells and the cultured cells contained scanty microtubules and dense-core neurosecretory granules. Chromosome analysis of this cell line showed monosomy for chromosomes 1,10,19 and X, and structural rearrangements involving chromosomes 8, 17 and 20, in addition to numerous double minutes. The N- myc oncogene was found to be amplified 40 to 80 fold in the transplanted and cultured tumor cells, as well as in the primary tumor cells. In situ hybridization with a digoxigenin labeled uridine-triphosphate N- myc RNA probe detected abundant mRNA in the tumor cells. This neuroblastoma line may become a valuable in vitro experimental model system for studies aimed at better characterization of neuroblastoma. Acta Pathol Jpn 41: 507 515, 1991.     

Metastatic neuroblastoma: new abnormalities on bone scintigraphy may not indicate tumour recurrence

Neuroblastoma is a potentially curable child-hood malignancy with survival rates of 20% reported even in advanced disease. Technetium-labelled methylene diphosphonate (Tc99m-MDP) scanning is well established as a method of assessing bone disease. We report four patients, with advanced neuroblastoma in complete or partial remission, in whom new abnormalities on bone scintigraphy were due to benign lesions. Correct management depends on the precise diagnosis of such lesions.     

Mobilization of intracellular Ca and suppression of inward currents in a neuronal hybrid cell line triggered by bradykinin

Bradykinin triggered intracellular Ca mobilizations and ionic conductance changes were studied in the neuroblastoma × glioma hybrid cell line NG108-15 using Ca-sensitive fluorescent indicator fura-2 under patch pipette whole cell voltage clamp condition. The time course of outward current induced by bradykinin was closely related to the time-course of [Ca²⁺]_i change. Following application of bradykinin, [Ca²⁺]_i increased transiently and then decreased below the basal level before bradykinin application. The inward currents activated by step-depolarization were suppressed after bradykinin application, but the time-course of the suppression did not go in parallel with the [Ca²⁺]_i changes: the suppression started before the [Ca²⁺]_i change emerged and outlasted the phase of [Ca²⁺]_i increase. Both transient type and long-lasting type Ca current were suppressed by bradykinin. [Ca²⁺]_i increase induced by high potassium depolarization was suppressed by bradykinin. Pertussis toxin did not affect the Ca transient nor the suppression of Ca channel induced by bradykinin. Our results suggest that the modifications of ionic channels by bradykinin could be through the other mechanisms than the well established activation of the G-protein leading to the IP₃ mechanisms and that the bradykinin receptor might couple with the pertussis toxin-insensitive G protein which regulates the calcium channels.     

阻断TrkB-BDNF信号传导通路对神经母细胞瘤细胞生长及凋亡的影响

目的：脑源性神经生长因子(BDNF)和其酪氨酸激酶受体B（TrkB）与神经母细胞瘤(NB) 细胞的化疗耐药及恶性预后密切相关。该研究探讨阻断TrkB-BDNF信号传导通路后，NB细胞对化疗药物敏感性的变化。方法：常规培养SH-SY5Y NB细胞，用nM浓度全反式维甲酸（ATRA）诱导TrkB高表达，加入BDNF、化疗药顺铂（CDDP）和特异性酪氨酸酶抑制剂K252a处理。MTT实验方法检测应用K252a前后细胞的存活率的变化；同时应用Western-blot方法检测应用K252a前后TrkB的磷酸化水平的变化；流式细胞仪（FCM）检测细胞凋亡率；透射电镜（TEM）观察凋亡细胞的形态与结构。结果：ATRA+BDNF+CDDP组细胞的存活率及凋亡率与对照组相比，差异无显著性（P>0.05）。而经K252a处理后，细胞对顺铂的敏感性增加，细胞的存活率明显降低，凋亡率明显升高，差异有显著意义。Western-blot分析显示K252a能够阻断TrkB的磷酸化。结论：阻断TrkB-BDNF信号传导通路可提高NB的化疗敏感性，逆转耐药。