9 research outputs found

    Conjunctive Therapy of Cisplatin With the OCT2 Inhibitor Cimetidine: Influence on Antitumor Efficacy and Systemic Clearance

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    The organic cation transporter 2 (OCT2) regulates uptake of cisplatin in proximal tubules and inhibition of OCT2 protects against severe cisplatin-induced nephrotoxicity. However, it remains uncertain whether potent OCT2 inhibitors such as cimetidine can influence the antitumor properties and/or disposition of cisplatin. Using an array of preclinical assays, we found that cimetidine had no effect on the uptake and cytotoxicity of cisplatin in ovarian cancer cells with high OCT2 mRNA levels (IGROV-1). Moreover, the antitumor efficacy of cisplatin in mice bearing luciferase-tagged IGROV-1 xenografts was unaffected by cimetidine (P = 0.39). Data obtained in 18 patients receiving cisplatin (100 mg/m(2)) in a randomized crossover fashion with or without cimetidine (800 mg×2) revealed that cimetidine did not alter exposure to unbound cisplatin, a marker of antitumor efficacy (4.37 vs 4.38 μg×h/mL; P = 0.86). These results support the future clinical exploration of OCT2 inhibitors as specific modifiers of cisplatin-induced nephrotoxicity

    PLPHP deficiency: clinical, genetic, biochemical, and mechanistic insights

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    Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery

    The impact of general and carbon-related environmental knowledge on attitudes and behaviour of US consumers

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    Global warming and carbon emissions have gained international attention. However, it would appear that consumers are still unclear about what it encompasses and how it relates to their individual behaviour. Using the Theory of Reasoned Action (TRA) as a guiding framework, this study presents a structural equation model that tests the relationships between carbon and environmental knowledge, environmental attitude and behaviour using a sample of US consumers. The findings of the research suggest that a positive relationship was found between general and carbon-specific knowledge, attitude towards the environment, and general and carbon-specific behaviours. Therefore, general and carbon-specific environmental behaviours are related and may be driven by general attitudes and knowledge (i.e. both carbon-specific and general environmental knowledge). The implications of the study would suggest that marketers, working in tandem with government policymakers, need to focus efforts on developing consumers' knowledge about specific sub-issues, such as global warming. However, additional research needs to be undertaken to develop marketing communication that accurately reflects the environmental impact of consumption behaviour, thereby allowing for considered consumption
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