A phase I and pharmacokinetic trial of terephthalamidine (NSC 57155) as a 120-hour continuous infusion

In this phase I study, terephthalamidine was administered as a 120-hour continuous infusion repeated every 21 days. Thirteen patients received 27 courses of terephthalamidine at four dose levels (14, 28, 46, and 70 mg/m²/day). Dose-limiting toxicity consisted of profound and intractable anorexia, weight loss and prostration in all patients. Toxicity was delayed and accompanied by hyponatremia and hypokalemia. No hematologic or other toxicity was documented. One patient with adenocarcinoma of the lung had a 40% decrease in mediastinal lymph nodes and resolution of a pleural effusion lasting 2 months. Pharmacokinetic analysis by HPLC was performed in all patients during their first course. The harmonic mean terminal half-life for terephthalamidine was 23 hours with a plasma clearance of 1.7 l/hr/m². Both plasma concentrations achieved during infusion (r² = 0.9) and area under the curve (AUC) (r² = 0.8) were proportional to increase in dose (p < 0.002). Renal excretion accounted for 64% of the total cumulative dose, with an average renal clearance of 1.16 l/hr/m². Due to the unacceptable toxicity seen at all doses with this schedule, no further studies are recommended unless the mechanism of toxicity is better understood and can be prevented.     

Bee Venom Protects against Rotenone-Induced Cell Death in NSC34 Motor Neuron Cells

Rotenone, an inhibitor of mitochondrial complex I of the mitochondrial respiratory chain, is known to elevate mitochondrial reactive oxygen species and induce apoptosis via activation of the caspase-3 pathway. Bee venom (BV) extracted from honey bees has been widely used in oriental medicine and contains melittin, apamin, adolapin, mast cell-degranulating peptide, and phospholipase A₂. In this study, we tested the effects of BV on neuronal cell death by examining rotenone-induced mitochondrial dysfunction. NSC34 motor neuron cells were pretreated with 2.5 μg/mL BV and stimulated with 10 μM rotenone to induce cell toxicity. We assessed cell death by Western blotting using specific antibodies, such as phospho-ERK1/2, phospho-JNK, and cleaved capase-3 and performed an MTT assay for evaluation of cell death and mitochondria staining. Pretreatment with 2.5 μg/mL BV had a neuroprotective effect against 10 μM rotenone-induced cell death in NSC34 motor neuron cells. Pre-treatment with BV significantly enhanced cell viability and ameliorated mitochondrial impairment in rotenone-treated cellular model. Moreover, BV treatment inhibited the activation of JNK signaling and cleaved caspase-3 related to cell death and increased ERK phosphorylation involved in cell survival in rotenone-treated NSC34 motor neuron cells. Taken together, we suggest that BV treatment can be useful for protection of neurons against oxidative stress or neurotoxin-induced cell death.     

NSC23766改善大鼠脑缺血后认知功能缺陷

目的:探讨Rac1在大鼠海马CA1区缺血性神经元损伤中的作用.方法:健康成年雄性SD大鼠制作四动脉闭塞全脑缺血模型,实验动物随机分为Sham、缺血再灌组(ischemia/reperfusion,I/R)、溶剂对照(Vehicle)组(I/R+生理盐水)、NSC23766组(I/R+NSC23766).采用激光共聚焦显微镜技术观察海马CA1区生存神经元.利用Morris水迷宫观察脑缺血再灌注后大鼠的空间学习记忆功能的变化情况.结果:与缺血再灌注组相比,Rac1抑制剂NSC23766组海马CA1区神经元生存数量增加;大鼠缺血后的空间学习记忆缺陷明显得到改善.结论:Rac1的激活可能是导致大鼠缺血再灌注后神经元损伤的重要因素,其抑制剂NSC23766可有效减轻这种损伤,为临床治疗缺血性脑中风提供理论依据.     

Neural stem cell grafts reduce the extent of neuronal damage in a mouse model of global ischaemia

The therapeutic potential of neural stem cell transplantation has been well demonstrated in many models of focal brain damage. However, few studies have sought to determine whether neural stem cells are therapeutic in models of diffuse brain injury, such as observed in Alzheimer's disease and global ischaemia. The present study investigated the effects of transplanted MHP36 neural stem cells on the extent of ischaemic damage in a mouse model of global ischaemia and the effects of the immunosuppressive agent cyclosporin A (CsA). C57Bl/6J mice received an intrastriatal graft of MHP36 neural stem cells 3 days after selective neuronal damage had been induced by global ischaemia. The experimental group was subdivided into CsA or saline controls. We discovered that grafts of MHP36 neural stem cells were able to differentiate into neurons and reduce the extent of ischaemic neuronal damage. This reduction was particularly apparent at 4 week post-transplantation and is independent of CsA immunosuppression. MHP36 cells survived robustly in host ischaemic brain and migrated away from the injection tract towards the caudate nucleus and corpus callosum. Although MHP36 grafts were associated with an acute inflammatory response from reactive astrocytes and microglia at 1 week post-transplantation, this decreased markedly by 4 weeks post-transplantation even in the absence of CsA immunosuppression. This is the first study showing a therapeutic benefit of neural stem cells in a highly diffuse brain injury, further highlighting the possibilities of stem cell transplantation for all types of neurodegenerative disease.     

Antisense peptide nucleic acid targeting GluR3 delays disease onset and progression in the SOD1 G93A mouse model of familial ALS

Glutamate excitotoxicity is strongly implicated as a major contributing factor in motor neuron degeneration in amyotrophic lateral sclerosis (ALS). Excitotoxicity results from elevated intracellular calcium ion (Ca(2+)) levels, which in turn recruit cell death signaling pathways. Recent evidence suggests that alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunit (GluR) stoichiometry is a dominant factor leading to excess Ca(2+) loading in neurodegeneration. In particular, the Ca(2+) permeable glutamate receptor subunit 3 (GluR3) has been implicated in several neurologic conditions such as bipolar disorder and epilepsy. Recent proteomic analysis within our group on the copper zinc superoxide dismutase (SOD1)(G93A) transgenic mouse model of familial ALS (FALS) reveals a potentially deleterious upregulation of GluR3 in spinal cord compared to that in wild-type littermates. Based on this finding we designed a 12mer antisense peptide nucleic acid (PNA) directed against GluR3. This sequence significantly reduced levels of GluR3 protein and protected neuroblastoma x spinal cord (NSC-34) cells against death induced by the AMPA receptor-specific agonist (S)-5-fluorowillardiine. We subsequently treated SOD1(G93A) mice thrice weekly with intraperitoneal injections of the antisense PNA (2.5 mg/kg) commencing at postnatal day 50. Mice treated with the antisense sequence had significantly extended survival compared to mice injected with a nonsense sequence. Western blot analysis, however, did not reveal a significant reduction in GluR3 protein levels in whole extracts of the lumbar spinal cord. These results suggest that interference with the GluR3 component of the AMPA receptor assembly may be a novel strategy for controlling excitotoxic destruction of motor neurons and may lead to new therapeutic opportunities for the treatment of human ALS.     

Opposing effects of low and high-dose clozapine on survival of transgenic amyotrophic lateral sclerosis mice

Clozapine is a potent atypical neuroleptic or antipsychotic agent used to relieve symptoms of early-diagnosed schizophrenia. Aside from well-described dopamine and serotonin receptor blockade effects, clozapine may also be neuroprotective through its modulation of the p75 neurotrophin receptor (p75(NTR)) and superoxide dismutase 1 (SOD1) expression. The death-signalling activities of both p75(NTR) and mutant SOD1 are implicated in motor neuron degeneration in humans and transgenic mice with amyotrophic lateral sclerosis (ALS). We therefore investigated the effects of clozapine in cell culture and mouse models of ALS. Clozapine dose-dependently inhibited full-length and cleaved p75(NTR) but not SOD1 protein expression in the motor neuron-like (NSC-34) cell line. Furthermore, low concentrations of clozapine protected NSC-34 cells from paraquat-mediated superoxide toxicity, nerve growth factor (NGF)-induced death signalling, and serum deprivation, whereas high concentrations potentiated death. Systemic thrice-weekly administration of low and high-dose clozapine to mutant superoxide dismutase 1 (SOD1(G93A)) mice produced differential effects on disease onset and survival. Low-dose treatment was associated with delayed locomotor impairment and death, compared to high-dose clozapine, which accelerated paralysis and mortality (P < 0.05). Increased death was not attributable to toxicity, as clozapine-induced agranulocytosis was not detected from blood analysis. High-dose clozapine, however, produced extrapyramidal symptoms in mice manifest by hindlimb rigidity, despite reducing spinal cord p75(NTR) levels overall. These results suggest that although clozapine may exert p75(NTR)-mediated neuroprotective activity in vitro, its profound antagonistic effects on dopaminergic and serotonergic systems in vivo at high doses may exacerbate the phenotype of transgenic ALS mice.     

针灸对SAMP8小鼠皮层神经干细胞增殖分化的影响

目的 探讨针刺、艾灸对快速老化小鼠(SAMP8)皮层NSC增殖分化的影响.方法 选用8月龄SAMP8雄性小鼠随机分为模型组、针刺组、艾灸组,以同龄雄性正常老化小鼠(SAMR1)为对照组.针刺组、艾灸组选用"百会"进行治疗,每天治疗1次,7 d为1个疗程,共治疗3个疗程.对照组和模型组每天在相同时间给予相同方式的抓取.处死前1 w开始给予BrdU腹腔注射,50 mg/kg ;治疗结束后,取皮层,用免疫荧光双标方法检测神经干细胞(NSC)增殖、分化.结果 (1)各组小鼠均存在皮层NSC增殖.与对照组比较,模型组、针刺组、艾灸组阳性细胞数减少(P＜0.01,P＜0.05);但模型组与针刺组、艾灸组之间比较,差异无统计学意义(P＞0.05).(2)各组小鼠均存在皮层NSC分化.与对照组相比,模型组NSC分化为神经元较少(P＜0.01,P＜0.05)、分化为胶质细胞较多(P＜0.01,P＜0.05);与模型组相比,针刺组NSC分化为神经元较多(P＜0.05)、分化为胶质细胞较少(P＜0.01,P＜0.05);艾灸组NSC分化为未成熟神经元较多(P＜0.05)、分化为成熟星形胶质细胞(P＜0.01)和少突胶质细胞较少(P＜0.05).结论 针刺、艾灸治疗3个疗程后,主要反映在促进NSC向不同方向分化的差异.其中,针刺主要促进SAMP8皮层NSC向神经元分化,抑制向胶质细胞分化;艾灸主要是促进其向未成熟神经元分化、抑制向成熟星形胶质细胞和少突胶质细胞分化.     

Rac1?HIF-1α在缺氧的人食管鳞癌Eca109细胞株中的表达及其对细胞增殖水平的影响

目的:探讨Rac1、HIF-1α mRNA和蛋白在缺氧的人食管鳞癌Eca109细胞株中的表达及其对细胞增殖水平的影响.方法:应用半定量RT-PCR、Western blot法检测缺氧条件下Eca109细胞株Rac1、HIF-1α的mRNA和蛋白表达水平;应用半定量RT-PCR和MTT法检测常氧和缺氧下Rac1特异性抑制剂NSC23766处理后人食管鳞癌Eca109细胞株HIF-1α的mRNA表达水平和细胞增殖水平.结果:缺氧条件下,人食管鳞癌Eca109细胞株中Rac1、HIF-1α的mRNA和蛋白表达水平均明显增高,约24 h到达高峰.用NSC23766处理人食管鳞癌Eca109细胞株后,HIF-1α mRNA表达水平降低,细胞增殖明显受到抑制.结论:Rac1和HIF-1α在缺氧状态下被激活,且可能均与缺氧诱导的肿瘤增殖相关.