Trimethoprim resistance was investigated in cystic fibrosis isolates of Pseudomonas cepacia. Determination of the MIC of trimethoprim for 111 strains revealed at least two populations of resistant organisms, suggesting the presence of more than one mechanism of resistance. Investigation of the antibiotic target, dihydrofolate reductase, was undertaken in both a susceptible strain and a strain w...

Trimetrexate (TMTXI is an anticancer drug with potential advantages over the more commonly used antifolate, methotrexate (MTX); however, its use has been limited by severe myelosuppression. Retroviral vectors containing mutant dihydrofolate reductase (DHFR) genes have been used to protect bone marrow cells from MTX, suggesting a similar approach could be used for TMTX. We first screened six ...

Mice carrying the gene Mx were resistant to the lethal action of a hepatotropic line of avian influenza A virus. In resistant animals, foci of liver necrosis were self-limiting, and maximal virus titers reached were much below those in susceptible animals. Resistance could not be abrogated by immunosuppressive treatment with cyclophosphamide, methotrexate, or procarbazine, although such treatme...

Introduction: Methotrexate as a single agent chemotherapy in most women with low risk gestational trophoblastic neoplasia (GTN) has been associated with high treatment rate. Combination of methotrexate with Vitamin A due to reduced number of chemotherapy regime courses is one of the treatment options for patients with low-risk GTN. Therefore, this study was performed with aim to determine the e...

The growth requirements and transport characteristics of folate compounds in a methotrexate-resistant L1210/R81 cell line were compared with parental cells. Concentrations for half-maximal growth of the resistant cells with folate (350 nM) and 5-formyltetrahydrofolate (20 nM) were found to be higher by 2.7-fold and 20-fold, respectively, relative to the parent, suggesting that changes had occur...

OBJECTIVE The association between chronic use of methotrexate and decreased risk of ischemic cardiovascular events (CVE) among patients with psoriatic or rheumatoid arthritis (RA) was investigated using a systematic review and meta-analysis. METHODS The studies should have recruited adults receiving methotrexate, followed up for at least one year. Moreover, studies should have reported "hard"...

Methotrexate and 6-mercaptopurine, important components of acute lymphoblastic leukemia treatment, are substrates for multidrug resistance-associated protein MRP4. Eight single nucleotide polymorphisms were analyzed in MRP4 gene, and 4 variants were identified as tagSNPs with frequency more than or equal to 5%. They were investigated for association with treatment responses in 275 children with...

BACKGROUND We previously showed that the anti-inflammatory drug, sulfasalazine (salicylazosulfapyridine, SASP), can arrest proliferation of MCF-7 and MDA-MB-231 mammary cancer cells by inhibiting uptake of cystine via the x(c-) cystine/glutamate antiporter. Here we examined SASP with regard to reduction of cellular glutathione (GSH) levels and drug efficacy-enhancing ability. METHODS GSH leve...