Liliana Rivera-Espinosa

Instituto Nacional de Pediatría, Ciudad de México, The Federal District, Mexico

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Publications (8)12.55 Total impact

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    ABSTRACT: Oxidative stress, which is a state of imbalance in the production of reactive oxygen species and nitrogen, is induced by a wide variety of factors. This biochemical state is associated with diseases that are systemic as well as diseases that affect the central nervous system. Epilepsy is a chronic neurological disorder, and temporal lobe epilepsy represents an estimated 40% of all epilepsy cases. Currently, evidence from human and experimental models supports the involvement of oxidative stress during seizures and in the epileptogenesis process. Hence, the aim of this review was to provide information that facilitates the processing of this evidence and investigate the therapeutic impact of the biochemical status for this specific pathology.
    Oxidative medicine and cellular longevity 01/2014; 2014:759293. · 3.36 Impact Factor
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    ABSTRACT: Hepatic encephalopathy (HE) is a common complication of cirrhosis, of largely reversible impairment of brain function occurring in patients with acute or chronic liver failure or when the liver is bypassed by portosystemic shunts. The mechanisms causing this brain dysfunction are still largely unclear. The need to avoid complications caused by late diagnosis has attracted interest to understand the mechanisms underlying neuronal damage in order to find markers that will allow timely diagnosis and to propose new therapeutic alternatives to improve the care of patients. One of the experimental approaches to study HE is microdialysis; this technique allows evaluation of different chemical substances in several organs through the recollection of samples in specific places by semi-permeable membranes. In this review we will discuss the contributions of microdialysis in the understanding of the physiological alterations in human hepatic encephalopathy and experimental models and the studies to find novel alternative therapies for this disease.
    International Journal of Molecular Sciences 08/2013; 14(8):16184-206. · 2.34 Impact Factor
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    ABSTRACT: It is estimated that at least 100 million people worldwide will suffer from epilepsy at some point in their lives. This neurological disorder induces brain death due to the excessive liberation of glutamate, which activates the postsynaptic N-methyl-D-aspartic acid (NMDA) receptors, which in turn cause the reuptake of intracellular calcium (excitotoxicity). This excitotoxicity elicits a series of events leading to nitric oxide synthase (NOS) activation and the generation of reactive oxygen species (ROS). Several studies in experimental models and in humans have demonstrated that certain antiepileptic drugs (AEDs) exhibit antioxidant effects by modulating the activity of various enzymes associated with this type of stress. Considering the above-mentioned data, we aimed to compile evidence elucidating how AEDs such as valproic acid (VPA), oxcarbazepine (OXC), and topiramate (TPM) modulate oxidative stress.
    Oxidative Medicine and Cellular Longevity 01/2013; 2013:598493.
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    ABSTRACT: Oxidative stress, a state of imbalance in the production of reactive oxygen species and nitrogen, is induced by a wide variety of factors. This biochemical state is associated with systemic diseases, and diseases affecting the central nervous system. Epilepsy is a chronic neurological disorder with refractoriness to drug therapy at about 30%. Currently, experimental evidence supports the involvement of oxidative stress in seizures, in the process of their generation, and in the mechanisms associated with refractoriness to drug therapy. Hence, the aim of this review is to present information in order to facilitate the handling of this evidence and determine the therapeutic impact of the biochemical status for this pathology.
    International Journal of Molecular Sciences 01/2013; 14(1):1455-76. · 2.34 Impact Factor
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    ABSTRACT: The bacteriostatic agent 4,4'-diaminodiphenylsulfone or dapsone (DDS) and some of its N,N'-dialkylated analogs have shown anticonvulsant and neuroprotective properties in different experimental models. In this study, we tested the ability of five DDS analogs (N,N'-dimethyldapsone, N,N'-diethyldapsone, N,N'-dipropyldapsone, N,N'-dibutyldapsone and N,N'-ditosyldapsone) to attenuate quinolinic acid-induced toxicity in vivo. Male Wistar rats were treated with either DDS or analogs (12.5mg/kg and equimolar doses respectively) 30min before quinolinic acid intrastriatal stereotaxic injection (240nmol/μl). Six days after injury, circling behavior was evaluated by counting ipsilateral turns for 1h after apomorphine challenge (1mg/kg, sc). Twenty-four hours later, rats were sacrificed and their corpora striata were dissected out to determine GABA content. Hemotoxicity of the analogs was assessed as the ability to produce methemoglobin (MHb) in vivo. Blood was sampled from tail vein within 18h after drugs administration. Methemoglobin levels were determined by visible spectrophotometry and mean profiles of MHb-percentage versus time were obtained. All of the analogs tested decreased the number of ipsilateral turns/hour, reducing up to 67% the turns counting (p<0.05) when compared to those induced in animals receiving quinolinic acid with no treatment. N,N'-dimethylated, N,N'-diethylated and N,N'-dibutylated analogs significantly prevented the decrease of intrastriatal GABA content (p<0.05). Methemoglobin produced by the administration of analogs was significantly lower than the levels of the group receiving dapsone (p<0.05). The neuroprotective effect of analogs and their diminished hemotoxicity make them potential candidates for therapeutic applications.
    Neuroscience Letters 09/2012; 528(1):1-5. · 2.06 Impact Factor
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    Liliana Carmona-Aparicio, Liliana Rivera-Espinosa, Hugo Juarez-Olguin
    Miscellanea on Encephalopathies - A Second Look, 04/2012; , ISBN: 978-953-51-0558-9
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    ABSTRACT: Neurodegenerative diseases constitute a worldwide health problem. Metals like iron and copper are essential for life, but they are also involved in several neurodegenerative mechanisms such as protein aggregation, free radical generation and oxidative stress. The role of Fe and Cu, their pathogenic mechanisms and possible therapeutic relevance are discussed regarding four of the most common neurodegenerative diseases, Alzheimer's, Parkinson's and Huntington's diseases as well as amyotrophic lateral sclerosis. Metal-mediated oxidation by Fenton chemistry is a common feature for all those disorders and takes part of a self-amplifying damaging mechanism, leading to neurodegeneration. The interaction between metals and proteins in the nervous system seems to be a crucial factor for the development or absence of neurodegeneration. The present review also deals with the therapeutic strategies tested, mainly using metal chelating drugs. Metal accumulation within the nervous system observed in those diseases could be the result of compensatory mechanisms to improve metal availability for physiological processes.
    Chemico-biological interactions 07/2010; 186(2):184-99. · 2.46 Impact Factor
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    ABSTRACT: Sildenafil extemporaneous formulations, used to treat pulmonary arterial hypertension (PAH) in hospitalised children, must be also stable and uniform in content. In this study, we determined content uniformity, stability and therapeutic efficacy of sildenafil in gelatine capsules containing 5 mg from three brands (Viagra ® , Maxifort ® and Apodefil ®). The powder from crushed tablets was distributed into 32 gelatine capsules for each brand. Content uniformity and stability at 25 and 40°C were analysed by HPLC-UV (µ µ µ µBondapack C 18 column, H 2 KPO 4 35 mM (pH 6.0)/ acetonitrile (53:47 v/v), 0.8 ml/min). Therapeutic efficacy of unitary doses was assessed in 25 patients (14 boys and 11 girls), according to clinical improvement and systolic pulmonary arterial pressure (SPAP) decrease, before and after taking sildenafil. Unitary doses showed content uniformity (4.93 ± 0.327 ≈ 5 mg) and were stable for 30 days at 25 and 40°C. SPAP values decreased to normal in 64% of the patients. Dyspnoea disappeared in 85% (11/13) and cyanosis in 67% (6/9). Two children (8%) showed no therapeutic response. Individualised doses of sildenafil in gelatine capsules are stable, uniform in content, and therapeutically effective, being an alternative to treat PAH in hospitalised and ambulatory patients.