Copper as a Collaborative Partner of Zinc-Induced Neurotoxicity in the Pathogenesis of Vascular Dementia.

Copper is an essential trace element and possesses critical roles in various brain functions. A considerable amount of copper accumulates in the synapse and is secreted in neuronal firings in a manner similar to zinc. Synaptic copper and zinc modulate neuronal transmission and contribute to information processing. It has been established that excess zinc secreted during transient global ischemia plays central roles in ischemia-induced neuronal death and the pathogenesis of vascular dementia. We found that a low concentration of copper exacerbates zinc-induced neurotoxicity, and we have demonstrated the involvement of the endoplasmic reticulum (ER) stress pathway, the stress-activated protein kinases/c-Jun amino-terminal kinases (SAPK/JNK) signaling pathway, and copper-induced reactive oxygen species (ROS) production. On the basis of our results and other studies, we discuss the collaborative roles of copper in zinc-induced neurotoxicity in the synapse and the contribution of copper to the pathogenesis of vascular dementia.

[Severe and uncommon complications of anticholinesterase intoxication in children].

BACKGROUND: The Northern region of the Negev desert is an endemic area of organophosphate and carbamate intoxications in Bedouin children. Most victims are intoxicated by drinking the poisonous material kept by the parents in soft drink bottles. Signs and symptoms of intoxication are commonly known and generally include various effects on the central nervous system, usually a decreased level of consciousness in children, cholinergic muscarinic (sweating, rhinorrhea, miosis, vomiting) and nicotinic (weakness) effects. Specific therapy includes Atropine Sulphate and Oximes. PURPOSE AND RESULTS: To describe the course of disease of four (out of 47) children admitted to the Division of Pediatrics with organophosphate or carbamate poisoning during a two-year period. The four children 3-17 years of age ingested the poisonous material: organophosphate chlorpyrifos (2 children); carbamate methomyl (one child) and an unidentified compound in another child. Three of the four patients ingested the poison in a suicide attempt. All 4 children suffered from severe and uncommon complications, including severe respiratory failure from different etiologies. In addition, two of the four suffered from a neurological deficit causing prolonged disability. Three had renal failure necessitating hemofiltration in one case. One child had severe hemodynamic failure and arrhythmias necessitating, among other therapy, the insertion of a temporary pace maker. Two children had (laboratory) pancreatitis. One of the children with severe respiratory failure died after 38 days of extracorporeal membrane oxygenation. CONCLUSIONS: Intoxications by anticholinesterase compounds are not uncommon among Bedouin children in the Negev. This public health threat should be prevented and completely eradicated by the health authorities. Severe intoxication, especially in cases arising after suicide attempts, wherein the amount of the poisonous material is large, may be complicated by life threatening, multi-organ failure during and after the initial phase of poisoning and may progress into prolonged disability and death.

Effect of race on vincristine-associated neurotoxicity in pediatric acute lymphoblastic leukemia patients.

BACKGROUND: This report examines the association between race and vincristine-associated neurotoxicity in pediatric patients with precursor B cell acute lymphoblastic leukemia (preB ALL). Given that in vitro vincristine is metabolized more efficiently by cytochrome P450 (CYP) 3A5 than by CYP3A4 and that 70% African-Americans (vs. 20% of Caucasians) express CYP3A5, one may hypothesize that African-Americans metabolize vincristine more efficiently resulting in lower vincristine exposure and associated-toxicity. PROCEDURE: A retrospective analysis of vincristine-related side effects in pediatric patients treated for preB ALL was performed. Data were compared between Caucasians (n = 92) and African-Americans (n = 21) to examine the relationship between race and vincristine-associated neurotoxicity thus using race as a surrogate for CYP3A5 genotype. Race, age, gender, disease subtype, highest grade of vincristine-associated neurotoxicity (per NIH Common Terminology Criteria for Adverse Events version 3.0), number of omitted and reduced vincristine doses, cumulative vincristine dose, and disease outcome were captured. RESULTS: 34.8% of Caucasians experienced symptoms consistent with vincristine-related neurotoxicity compared to 4.8% of African-Americans (P = 0.007). The average grade of neurotoxicity for Caucasians was 2.72 versus grade 1 neurotoxicity in the African-American (P < 0.0001). Four percent of total doses administered to Caucasian patients were reduced due to vincristine-related neurotoxicity compared to 0.1% given to African-Americans (P < 0.0001). 1.2% of all protocol-indicated doses for Caucasians were held due to severe vincristine-associated toxicity compared to 0.1% of doses for African-Americans (P < 0.01). CONCLUSIONS: The data support the hypothesis pharmacogenetic polymorphisms in CYP3A5 expression contribute to variability in vincristine metabolism and neurotoxicity.

Development of the Behavioral Assessment and Research System (BARS) to detect and characterize neurotoxicity in humans.

The Behavioral Assessment and Research System (BARS) is a computer-based testing system designed to assess neurobehavioral function in humans. It was developed to provide a series or battery of neurobehavioral tests optimized for the detection of neurotoxicity in non-mainstream human populations, specifically people with limited education or literacy. Key to meeting this goal were simply-stated instructions divided into an elemental series of steps, a 9BUTTON response unit to replace the computer keyboard for responding, and spoken instructions. Modifications all underwent serial testing in target populations to successively hone the changes to be more effective. A similar process was followed when developing adjustable parameters, test reliability assessments, and when implementing these tests with populations from different cultural groups and children. The principles and experiences that guided the development of BARS should inform the development of future testing systems to ensure that the new tests can be used with non-mainstream populations, which may be increasingly subject to neurotoxic exposures.

Safety analysis of FOLFOX4 treatment in colorectal cancer patients: a comparison between two Asian studies and four Western studies.

PURPOSE: Oxaliplatin-based therapy, notably FOLFOX4 (5-fluorouracil, leucovorin, and oxaliplatin), is a standard regimen approved globally for the treatment of metastatic colorectal cancer, and as adjuvant treatment of colon cancer. As part of the Japanese submission for the adjuvant indication, the safety profile of FOLFOX4 regimen was compared in Asian and Western patients. PATIENTS AND METHODS: A total of 3359 patients with colorectal cancer treated with the FOLFOX4 regimen were included in the analyses: 1515 from 2 Asian studies (Japanese Post Marketing Surveillance and Multicenter Asia Study in Adjuvant Treatment of Colon Cancer with Oxaliplatin/5-FU/LV), and 1844 from 4 Western studies (EFC2962, N9741, EFC4584, and Multicenter International Study of Oxaliplatin/5-Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer). Doses administered and safety parameters were analyzed by using common definitions and programs. RESULTS: Demographic and baseline characteristics were comparable between Asian and Western patients. Patients received FOLFOX4 for a median of 6-12 cycles, which ranged from 16 to 28 weeks. Median dose intensities of oxaliplatin and of 5-fluorouracil, bolus and infusion, were within the ranges of 33 to 36 mg/m(2)/week, 297 to 338 mg/m(2)/week, and 467 to 510 mg/m(2)/week, respectively. Most frequently reported adverse events (AE) included hematologic, gastrointestinal, and neurosensory adverse events (NSAE). The incidence of grade ≥3 neutropenia ranged from 37% (422 of 1134) to 52% (83 of 159) in Asian and 41% (455 of 1108) to 56% (144 of 259) in Western studies; of diarrhea, ranged from 1.4% (3 of 222) to 6.3% (10 of 159) and 11% (30 of 268 or 120 of 1108) to 14% (36 of 259); of NSAEs, from 1.9% (21 of 1134) to 4.4% (7 of 159) and 9.3% (25 of 268) to 19% (39 of 209); and of allergic reactions, from 0.6% (7 of 1134) to 3.1% (5 of 159) and 1.1% (3 of 268) to 3.0% (33 of 1108), respectively. The probability of grade ≥3 NSAEs and diarrhea was statistically significantly lower in Asian than in Western studies by using a log-rank test. CONCLUSION: There was no evidence that Asian patients experienced worse toxicity than did Western patients when treated with FOLFOX4, and trends toward reduced neurotoxicity and diarrhea among Asian patients were observed.

The effects of organophosphate pesticide exposure on Hispanic children's cognitive and behavioral functioning.

OBJECTIVE: This study investigates the effects of Organophosphate (OP) pesticides exposure on the cognitive and behavioral functioning of Hispanic children living in an agricultural community. METHODS: Forty-eight children were administered a battery of cognitive measures, and their parents and teachers completed behavior rating scales. Children provided a urine sample for analysis of OP pesticides metabolites. RESULTS: All children had a detectable level of at least one OP pesticide metabolite. Higher OP pesticide metabolite concentration levels were significantly correlated with poorer performance on some subtests of the Wisconsin Card Sorting Test. However, the significance of this association was dependent upon the inclusion of two samples with noticeable higher OP pesticide metabolite concentration levels. CONCLUSIONS: Short-term OP pesticide exposure seems to have deleterious effects on children's speed of attention, sequencing, mental flexibility, visual search, concept formation, and conceptual flexibility. This study is among a relatively small number of studies investigating an extremely complex problem. Limitations and suggestions for future studies are discussed.