Este artículo es producto de un estudio colectivo realizado en el primer semestre lectivo del 2016, cuyo principal propósito fue describir la forma en que la estructura de mercado bajo competencia monopolística, incide en la determinación del punto de equilibrio de la empresa Espíritu Urbano. Lo anterior se logra a partir de una investigación descriptiva y una aproximación al estudio de caso. Se concluye que los aspectos que componen la estructura de mercado en competencia monopolística influyen directamente en la determinación del punto de equilibrio de la empresa, tanto en términos económicos como contables, toda vez que intervienen directamente en la determinación de los costos, ya sea de producción o de comercialización del producto final.
BackgroundMethotrexate (MTX) as monotherapy or in combination, is the most commonly Disease-Modifying-AntiRheumatic-Drug (DMARDs) used in rheumatoid arthritis (RA). About 40% of patients do not respond to treatment or have adverse effects. The genetic variability could be responsible for this phenomenon. Different studies suggest associations between polymorphisms in the enzymes involved in the metabolic pathway of MTX with alterations in the efficacy and toxicity.ObjectivesDetermine the polymorphisms of the enzymes involved in MTX metabolism in a group of Colombian patients.Methods400 patients with RA over 18 years old, diagnosed according to the ACR/EULAR classification criteria, who consecutively attended an outpatient RA clinic between March 2015 and December 2016 were included. MTX efficacy was defined by DAS28 score ≥3.2, liver toxicity by elevation of transaminases above three times the normal value, Haematological toxicity by: leukocytes<4,000, Hb <9.5, platelets<150,000, renal toxicity: creatinine >1.5. The single nucleotide polymorphisms (SNPs) studied were MTHFR C677T, MTHFR A1298C, ATIC C347G, RFC1 G80A, FPGS-AG and DHFR-CT and were identified by the technique of polymerase chain reaction in real time (RT-PCR).ResultsThe mean age of patients was 60.7±13.9 years, the duration of the disease was 13.2±10.9 years and 76% were women. A significant increase in the frequency of MTHFR C677T and A1298C SNPs (p=0.05 and p=0.048) were found in the responding patients compared to non-responders. The DHFR-CT and the ATIC C347G SNPs were significantly increased in patients with any toxicity to MTX (p=0.0095 and p=0.005 respectively). We did not find a significant difference between the polymorphisms studied with any specific toxicity.Abstract AB0004 – Table 1 Polymorphisms nActivity (%)Remission (%) OR-95%(IC)p
MTHFR C677CCCCTT3448126318937 (20)152 (80)15544 (28)111 (72) 1.62 (1.0–2.68) 0.05MTHFR A1298AATT38131269219172 (79)47 (21)162140 (86)22 (14) 1.74 (1.01–3.02) 0.048DHFRCCTT394233 (58.3)161 (25.8)225131 (58.2)91 (40.5)16595 (57.6)68 (41.2) 1.03(0–68–1.55) 0.484FPGSAAGG400137 (34.3)263 (65.7)22574 (32.9)151 (67.7)16557 (34.5)108 (65.5) 1.92 (0.69–1.41) 0.406Abstract AB0004 – Table 2ConclusionsThe Colombian population has similar statistical data compared to the global studies regarding the association of SPNs with the efficacy and toxicity of methotrexate, however the polymorphisms associated with inefficiency in the literature are not replicated in our data. These SNPs could be established as biomarkers to the methotrexate response in terms of efficacy and toxicity in our Colombian population with RA.Reference[1] Fan H, Li Y, Zhang L, Li W. Lack of association between MTHFR A1298C polymorphism and outcome of methotrexate treatment in rheumatoid arthritis patients: Evidence from a systematic review and meta-analysis. Int J Rheum Dis2017;20(5):526–40.Disclosure of InterestNone declared
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.