Clinical efficacy of pemetrexed disodium in maintenance treatment of advanced lung adenocarcinoma / 中国基层医药

Objective:To investigate the clinical efficacy and adverse reactions of pemetrexed disodium in the maintenance treatment of advanced lung adenocarcinoma after chemotherapy with pemetrexed disodium and platinum.Methods:The clinical data of 35 patients with stage Ⅳ lung adenocarcinoma who received chemotherapy with pemetrexed disodium and platinum and were well treated in Beijing Huairou Hospital from January 2013 to August 2020 were retrospectively analyzed. Maintenance therapy with pemetrexed disodium was initiated after the completion of combination chemotherapy until disease progression. The clinical characteristics, therapeutic effects, adverse reactions, progression-free survival, and overall survival of the 35 patients were evaluated.Results:Among the 35 patients, no patients had complete remission, 11 patients had partial remission, 22 patients had stable disease, and 2 patients had progressive disease. The objective remission rate was 31.4%, disease control rate was 94.3%, median progression-free survival was 9.53 months, median overall survival was 18.21 months, 1-year survival rate was 68.6%, 2-year survival rate was 31.4%, and 3-year survival rate was 11.4%. Gender, age, smoking, and the baseline characteristics of patients undergoing first-line pemetrexed disodium or second-line pemetrexed disodium treatment had no effects on progression-free survival (all P > 0.05). Positive gene mutation and receiving four or more chemotherapy cycles had a protective effect on progression-free survival (both P < 0.05). Chemotherapy-related adverse reactions mainly included myelosuppression, nausea, elevated transaminase, and nephrotoxicity, all of which were mild and were relieved after symptomatic treatment. Conclusion:Pemetrexed disodium is effective and safe in the maintenance treatment of advanced lung adenocarcinoma. The results of this study are scientific.

Short-term efficacy of pemetrexed combined with cisplatin in the treatment of malignant pleural effusion and its effect on serum carbohydrate antigen 199 level and circulating tumor cells / 中国基层医药

Objective:To investigate the short-term efficacy of pemetrexed combined with cisplatin in the treatment of malignant pleural effusion and its effect on serum carbohydrate antigen 199 level and circulating tumor cells.Methods:Sixty patients with advanced lung cancer complicated by malignant pleural effusion who received treatment in Healthcare Group of Cixi Third People's Hospital, China from January 2017 to January 2020 were included in this study. They were randomly assigned to receive intrapleural injection of cisplatin (cisplatin alone group, n = 30) or intrapleural injection of cisplatin combined with intravenous injection of pemetrexed (cisplatin + pemetrexed group, n = 30) after thoracic drainage. Before and 1 month after treatment, pleural effusion was measured to evaluate clinical efficacy and improvement in quality of life. Serum carcinoembryonic antigen level, serum carbohydrate antigen 199 level and circulating tumor cells were determined. Adverse reactions during the treatment were recorded. Results:Total effective rate and the rate of improvement in quality of life in the cisplatin + pemetrexed group were 66.67% (20/30) and 70.00% (21/30), respectively, which were significantly higher than those in the cisplatin alone group [40.00% (12/30) and 43.33% (13/30), χ2 = 4.286, 4.344, both P < 0.05]. After treatment, serum carcinoembryonic antigen and serum carbohydrate antigen 199 levels in each group were significantly decreased compared with before treatment (both P < 0.05). Serum carcinoembryonic antigen and serum carbohydrate antigen 199 level in the cisplatin + pemetrexed group were (22.26 ± 5.13) ng/mL and (20.12 ± 4.35) U/mL, respectively, which were significantly lower than those in the cisplatin alone group [(31.64 ± 6.46) ng/mL, (28.07 ± 5.61) U/mL, t = 6.228, 3.134, both P < 0.05). In the cisplatin alone group, there was no significant difference in the proportion of circulating tumor cells before and after treatment ( P > 0.05). In the cisplatin + pemetrexed group, the proportion of circulating tumor cells after treatment was significantly lower than that before treatment ( χ2 = 4.286, P < 0.05). After treatment, there was no significant difference in the proportion of circulating tumor cells between the two groups ( P > 0.05). During the treatment, there were no significant differences in the incidences of rash, nausea and vomiting, leukopenia, and anemia between the two groups (all P > 0.05). Conclusion:Pemetrexed combined with cisplatin in the treatment of malignant pleural effusion exhibits better short-term efficacy than cisplatin alone. The combined therapy is more conducive to relieving clinical symptoms and improving the quality of life with higher safety than monotherapy.

Improved synthesis process of diethyl N-[4-[(2,4-diaminopyrido[3,2-d] pyrimidin-6-yl) methylamino] benzoyl]-L-glutamate / 北京大学学报(医学版)

Objective:To establish a new approach to synthesis of diethyl N-[4-[(2,4-diaminopyrido [3,2-d]pyrimidin-6-yl)methylamino]benzoyl]-L-glutamate.Methods:Target compound (5) was syn-thesized by the use of (2,4-dioxo-tetrahydropyridopyrimidin-6-yl) methyl acetate (1) as starting material via hydrolysis, chlorination, condensation with diethyl (p-aminobenzoyl)glutamate and aminolysis.Re-sults:A new approach to synthesis of diethyl N-[4-[(2,4-diaminopyrido[3,2-d]pyrimidin-6-yl)methyl-amino]benzoyl]-L-glutamatewas established .This synthetic route has hydrolysis reaction , chlorination, diethyl N-( p-aminobenzoyl )-L-glutamate condensation reaction and ammonolysis reaction .The total yield is 36.7%.The structures of those compounds have identified by 1 H nuclear magnetic resonance , 13 C nu-clear magnetic resonance and mass spectrometry .This synthetic route avoid the unstable brominated re-action product and improves the harsh condition of ammonolysis reaction .Conclusion:The new synthetic route has improved the reaction condition and the stability of the intermediate , and increased the extent of the derivative compounds , which has great significance to anti-folic acid of anti-tumor inhibitor synthesis .

Polimorfismos en los genes de dihidrofolato-reductasa ( dhfr ) y dihidropteroato-sintasa ( dhps ) y modelado estructural del gen dhps en aislamientos colombianos de Toxoplasma gondii / Gene polymorphisms in the dihydrofolate reductase ( dhfr ) and dihydropteroate synthase ( dhps ) genes and structural modelling of the dhps gene in Colombian isolates of Toxoplasma gondii

Introducción. No existen reportes sobre las variaciones en la secuencia de los genes blanco de los medicamentos anti- Toxoplasma en aislamientos provenientes de Suramérica. Objetivo. Clonar y secuenciar los genes de la dihidrofolato-reductasa ( dhfr ) y la dihidropteroato-sintetasa ( dhps ) de la cepa de referencia RH y de dos aislamientos colombianos de Toxoplasma gondii. Materiales y métodos. Se obtuvieron dos aislamientos de T. gondii en líquido céfalorraquídeo de pacientes colombianos positivos para HIV con toxoplasmosis cerebral. Se extrajo el ADN de los genes dhfr y dhps y se amplificaron mediante reacción en cadena de la polimerasa (PCR). Los productos fueron clonados en el vector pGEM-T y secuenciados. Resultados. Se encontró un cambio de adenina por guanina (A « G) en la posición 235 del exón 2 del gen dhps , dos cambios de guanina por citocina (G « C) en las posiciones 259 y 260 y un cambio de timina por guanina (T « G) en la posición 371 del exón 4 del gen dhps. Por análisis bioinformático, en este último exón se identificó un polimorfismo no sinónimo en la región codificante, que podría llevar al cambio de una Glu (CAA o CAG) por una His (codificada por los codones AAU o AAC). Se calculó el modelo estructural de la enzima dihidropteroato-sintetasa (DHPS) de T. gondii y se identificaron las modificaciones en la estructura secundaria ocasionadas por las mutaciones. Conclusiones. La metodología estandarizada puede servir como base para la búsqueda de polimorfismos en muestras de pacientes con diferentes manifestaciones clínicas de toxoplasmosis y para establecer su posible relación con los cambios en la sensibilidad a los antifolatos y la reacción al tratamiento.

Introduction: There are no reports describing polymorphisms in target genes of anti- Toxoplasma drugs in South American isolates. Objective: This study sought to perform cloning and sequencing of the dihydrofolate reductase ( dhfr ) and dihydropteroate-synthase ( dhps ) genes of the reference Rh strain and two Colombian isolates of Toxoplasma gondii . Materials and methods: Two isolates were obtained from the cerebrospinal fluid of HIV-infected patients with cerebral toxoplasmosis. A DNA extraction technique and PCR assay for the dhfr and dhps genes were standardized, and the products of amplification were cloned into Escherichia coli and sequenced. Results: One polymorphism (A « G) was found at position 235 of exon 2 in the dhps gene. In addition, two polymorphisms (G « C) at positions 259 and 260 and one polymorphism (T « G) at position 371 within exon 4 of the dhps gene were detected. In this last exon, a bioinformatic analysis revealed a non-synonymous polymorphism in the coding region that could lead to the substitution of Glu (CAA or CAG) for His (encoded by codons AAU or AAC). A structural model of the T. gondii DHPS protein was calculated, and the results revealed modifications in secondary structure due to mutations. Conclusions: The methods described in this study can be used as a tool to search for polymorphisms in samples from patients with different clinical manifestations of toxoplasmosis and to examine their relationship with the therapeutic response.

Biochemical characterization of the bifunctional enzyme dihydrofolate reductase-thymidylate synthase from Leishmania ( Viannia ) and its evaluation as a drug target / Caracterización bioquímica de la enzima bifuncional dihidrofolato reductasa-timidilato sintasa de Leishmania ( Viannia ) y su evaluación como blanco molecular

Introduction. Dihydrofolate reductase (DHFR) has been used successfully as a drug target in the area of anti-bacterial, anti-cancer and anti-malarial therapy. Although this bifunctional enzyme is also a potential drug target for treatment of leishmaniasis, there have been no reports on its efficacy against Leishmania ( Viannia ) species . Materials and methods. The gene encoding the bifunctional DHFR and thymidylate synthase (TS) of Le. (V.) braziliensis was isolated and expressed in E. coli. The enzyme was purified and characterized. The inhibitory effects of antifolates and four aporphine alkaloids on its activity were evaluated. Results. The full-length gene consists of a 1560-bp open reading frame encoding a 58 kDa translated peptide containing DHFR and TS domains linked together in a single polypeptide chain. The recombinant DHFR-TS enzyme revealed K m and V max values of 55.35 ± 4.02 µ M (mean ± SE) and 0.02 ± 5.34 x 10 -4 µ M/min respectively for dihydrofolic acid (H 2 F). The Le. braziliensis rDHFR-TS have Ki values for antimicrobial antifolates in the µM range. Methotrexate (MTX) was a more-potent inhibitor of enzymatic activity ( Ki = 22.0 µM) than trimethoprim ( Ki = 33 µM) and pyrimethamine ( Ki = 68 µM). These Ki values are significantly lower than those obtained for the aporphine alkaloids. Conclusion. The results of the study show the inhibitory effect of antifolate drugs on enzymatic activity, indicating that Le. braziliensis rDHFR-TS could be a model to studying antifolate compounds as potential antiprotozoal drugs.

Introducción. La dihidrofolato reductasa (DHFR) se ha utilizado como blanco molecular en tratamientos antibacterianos, anticancerígenos y antipalúdicos. También, actúa como blanco molecular en Leishmania ; sin embargo, no existen reportes de la enzima bifuncional en especies de Leishmania ( Viannia ). Materiales y métodos. Se ha aislado y expresado en Escherichia coli el gen que codifica para la enzima bifuncional DHFR y la timidilato-sintasa (TS) de Leishmania braziliensis . La enzima recombinante se purificó y caracterizó, y se evaluó el efecto inhibitorio de algunos antifolatos, así como de cuatro alcaloides aporfínicos. Resultados. El gen se compone de aproximadamente 1.560 pb y codifica un péptido de 58 kDa que contiene los dominios DHFR y TS ligados en una sola cadena polipeptídica. La enzima recombinante DHFR-TS, utilizando el dihidrofolato (H2F) como sustrato, presentó valores de K m y V max de 55,35 ± 4,02 (media ± el error estándar de la media) y de 0,02 ± 5,34 x 10 -4 , respectivamente. La enzima rDHFR-TS de L. braziliensis presentó valores de Ki para los antifolatos en el rango de micras. El metotrexato fue el inhibidor más potente de la actividad enzimática ( Ki =22,0 mM) en comparación del trimetoprim ( Ki =33 mM) y la pirimetamina ( Ki =68 mM). Estos valores de Ki son significativamente más bajos en comparación con los obtenidos para los alcaloides aporfínicos. Conclusión. Los resultados muestran el efecto inhibitorio de los antifolatos sobre la actividad enzimática, lo cual indica que la rDHFR-TS de L. braziliensis podría ser un modelo para estudiar moléculas antiprotozoarias potenciales.