Cancer is a leading cause of death worldwide. The cancer incidence rate in Chile is 133.7/100,000 inhabitants and it is the second cause of death, after cardiovascular diseases. Most of the antineoplastic drugs are metabolized to be detoxified, and some of them to be activated. Genetic polymorphisms of drug-metabolizing enzymes can induce deep changes in enzyme activity, leading to individual variability in drug efficacy and/or toxicity. The present research describes the presence of genetic polymorphisms in the Chilean population, which might be useful in public health programs for personalized treatment of cancer, and compares these frequencies with those reported for Asian and Caucasian populations, as a contribution to the evaluation of ethnic differences in the response to chemotherapy. We analyzed 23 polymorphisms in a group of 253 unrelated Chilean volunteers from the general population. The results showed that CYP2A6*2, CYP2A6*3, CYP2D6*3, CYP2C19*3, and CYP3A4*17 variant alleles are virtually absent in Chileans. CYP1A1*2A allele frequency (0.37) is similar to that of Caucasians and higher than that reported for Japanese people. Allele frequencies for CYP3A5*3(0.76) and CYP2C9*3(0.04) are similar to those observed in Japanese people. CYP1A1*2C(0.32), CYP1A2*1F(0.77), CYP3A4*1B(0.06), CYP2D6*2(0.41), and MTHFR T(0.52) allele frequencies are higher than the observed either in Caucasian or in Japanese populations. Conversely, CYP2C19*2 allelic frequency (0.12), and genotype frequencies for GSTT1 null (0.11) and GSTM1 null (0.36) are lower than those observed in both populations. Finally, allele frequencies for CYP2A6*4(0.04), CYP2C8*3(0.06), CYP2C9*2(0.06), CYP2D6*4(0.12), CYP2E1*5B(0.14), CYP2E1*6(0.19), and UGT2B7*2(0.40) are intermediate in relation to those described in Caucasian and in Japanese populations, as expected according to the ethnic origin of the Chilean population. In conclusion, our findings support the idea that ethnic variability must be considered in the pharmacogenomic assessment of cancer pharmacotherapy, especially in mixed populations and for drugs with a narrow safety range.
RFamide-related peptide (RFRP-3), is a regulator of GnRH secretion from the brain, but it can also act in human ovary to influence steroidogenesis. We aimed to study the putative local role of RFRP-3 in the ovary and its potential participation in the development of a polycystic ovary phenotype induced by chronic sympathetic stress (cold stress). We used adult Sprague-Dawley rats divided into control and stressed groups. In both groups we studied the effect of intraovarian exposure to RFRP-3 on follicular development and plasma ovarian steroid concentrations. We also tested the effect of RFRP-3 on ovarian steroid production in vitro. Chronic in vivo intraovarian exposure to RFRP-3 decreased basal testosterone concentrations and cold stress-induced progesterone production by the ovary. In vitro, RFRP-3 decreased hCG-induced ovarian progesterone and testosterone secretion. Immunohistochemistry and mRNA expression analysis showed a decrease in RFRP-3 and expression of its receptor in the ovary of stressed rats, a result which is in line with the increased testosterone levels found in stressed rats. In vivo application of RFRP-3 recovered the low levels of secondary and healthy antral follicles found in stressed rats. Taken together, our data indicate a previously unknown response of hypothalamic and ovarian RFRP-3 to chronic cold stress, influencing ovarian steroidogenesis and follicular dynamics. Thus, it is likely that RFRP-3 modulation in the ovary is a key component of development of the polycystic ovary phenotype.
Abstract. Polycyclic aromatic hydrocarbons (PAHs) contained in tobacco smoke acquire carcinogenicity following their activation by xenobiotic-metabolizing enzymes to highly reactive metabolites. The cytochrome P4501A1 (CYP1A1) enzyme is central to the metabolic activation of these PAHs, and GSTM1 is the main enzyme responsible for its detoxification. CYP1A1 and GSTM1 polymorphisms were evaluated in 124 Chilean healthy controls and 48 oral cancer patients through PCR-based restriction fragment length polymorphism. In the healthy controls, frequencies of the CYP1A1 variant alleles for m1 (CYP1A1 * 2A) and the GSTM1null genotype were found to be 0.25 and 0.19, respectively. In the oral cancer patients, these frequencies were 0.33 and 0.50, respectively. Thus, the GSTM1 and m1 rare alleles were significantly more frequent in the oral cancer patients compared to the controls. The estimated relative risk for oral cancer associated with the single genotype CYP1A1 or GSTM1 was 2.08 for wt/m1, 1.04 for m1/m1 and 4.16 for the GSTM1null genotype. For smokers, the estimated relative risk (adjusted by age and gender) was higher in the individuals carrying the m1 allele of CYP1A1 [wt/m1: odds ratio (OR)=5.68, P=0.0080; m1/m1: OR=7.77, P=0.0420] or GSTM1null genotype (OR=20.81, P<0.0001). Combined genotypes CYP1A1 and GSTM1 increased the risk significantly (wt/m1/GSTM1null: OR=19.14, P=0.0030; m1/ m1/GSTM1null: OR=21.39, P=0.0130). Taken together, these findings suggest that Chilean individuals carrying single or combined GSTM1 and CYP1A1 polymorphisms may be more susceptible to oral cancer induced by environmental tobacco smoking.
218Determinación del polimorfismo de CYP2C9*2 y su relación con la farmacocinética de acenocumarol en voluntarios sanos. Resumen:Antecedentes: La mayoría de los pacientes que reciben tratamientos con anticoagulantes orales por periodos prolongados presentan variabilidad en la respuesta. El acenocumarol es el anticoagulante oral más prescrito en nuestro país, es biotransformado principalmente por CYP2C9 e investigaciones recientes demuestran que la variante CYP2C9*2 es una de las responsables de la variabilidad de respuesta a acenocumarol.Objetivo: Determinar las diferencias en los pará-metros farmacocinéticos de acenocumarol en voluntarios que presentan la variante alélica CYP2C9*2.Métodos: Se estudiaron 24 voluntarios sanos.La detección de genotipos se realizó mediante PCR-RFLP y los parámetros farmacocinéticos se obtuvieron mediante la concentración plasmática de acenocumarol usando un método validado para UPLC-MS/MS.Resultados: Del total de 24 voluntarios,19 tenían el genotipo CYP2C9*1/*1 (wt/wt), 4 tenían genotipo CYP2C9*1/*2 (heterocigoto) y 1 voluntario tenía genotipo de CYP2C9*2/*2 (homocigoto recesivo). Los parámetros farmacocinéticos del acenocumarol no fueron significativamente diferentes entre los individuos con genotipo CYP2C9*2 y CYP2C9*1. Sin embargo, la farmacocinética de acenocumarol del individuo CYP2C9*2/*2 mostró diferencias relevantes con respecto a la observada en el grupo CYP2C9*1/*1 (tmáx aumentó 1,4 veces, ke disminuyó 1,8 veces y t1/2 aumentó 1,7 veces).Conclusión: La farmacocinética de acenocumarol en el individuo con el genotipo CYP2C9*2/*2 refleja una potencial relevancia de este polimorfismo en el tratamiento con acenocumarol. Aim: to determine pharmacokinetics parameters of acenocumarol in volunteers exhibiting the CYP2C9*2 polymorphic variant. Methods:Genotype detection was performed using PCR-RFLP and pharmacokinetics parameters were obtained from the acenocumarol concentrations, using a UPLC-MS/MS validated method. The project was approved by the institutional Ethics Committee of the University of Chile's Faculty of Medicine.Results: 19 out of 24 volunteers had the CYP2C9*1/*1 genotype, 4 the CYP2C9*1/*2 genotype (heterozygous) and 1 subject had the CYP2C9*2/*2 genotype (recessive homozygous). No statistically significant differences between acenocumarol pharmacokinetics parameters of CYP2C9*2 compared to those with normal variant, CYP2C9*1were observed.. However, a single individual with the CYP2C9*2/*2 genotype showed different pharmacokinetics parameters: tmáx and t1/2 were increased 1.4 and 1.7 times, respectively, and kc was 1.8 times lower compared to the group with the CYP2C9*1/*1 genotype. Conclusion:There are clear differences in genotype-dependent acenocoumarol pharmacokinetics in individuals with the CYP2C9*2/*2 genotype, reflecting a potential relevance of this polymorphism in anticoagulation with acenocumarol.Keywords: Pharmacogenetics, CYP2C9*2, anticoagulants, acenocoumarol.Determinación del polimorfismo de CYP2C9*2 y su relación con la farmacocinética de acenocum...
Ipomoea reniformis Chaos is claimed in Indian traditional medical practice to be useful in the treatment of epilepsy and neurological disorders. In the present study, pretreatment effect of methanolic extract of Ipomoea reniformis on epilepsy and psychosis was evaluated in rodents using standard procedures. Besides evaluating epileptic and behavioral parameters, neurotransmitters such as Gamma-Amino Butyric Acid (GABA) in epilepsy and in psychosis dopamine, noradrenaline and serotonin contents in the rodent brain were estimated. The extract pretreatment reduced maximal electro shock; Isoniazid (INH) and Pentylenetetrazole (PTZ) induced seizures and also significantly inhibited the attenuation of brain GABA levels by INH and PTZ in mice. These results suggested that the observed beneficial effect in epilepsy may be by enhancing the GABAergic system. The test drug also inhibited the apomorphine induced climbing and stereotyped behavior and showed significantly reduced levels of brain dopamine, noradrenaline and serotonin which may be due to blocking of central dopaminergic, noradrenergic and serotonergic pathways or by enhancing the GABAergic system. The results obtained in present study suggest that the title plant possesses antiepileptic and antipsychotic activities in rodents.
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