A study was undertaken to evaluate the Nucleolar organizing regions (NOR) count and histopathological changes in rat’s liver treated with methotrexate (MTX). Male Wistar rats aged 4 months, maintained in our institution were used in the present study. Animals were injected intraperitonealy with 3 different doses of methotrexate on alternative days for one week and the animals were sacrifi...

Many laboratory strains of Escherichia coli are resistant to methotrexate (MTX), a folate analogue that binds dihydrofolate reductase (DHFR). Mutations that inactivate either tolC or acrA confer MTX sensitivity. Further, overexpression of a fusion protein with DHFR activity reverses this sensitivity by titrating out intracellular MTX. These results suggest that MTX accumulates in cells where mu...

Methotrexate reduces intracellular pools of 5-methyltetrahydrofolate and could result in reduced conversion of homocysteine to methionine by methionine synthetase. This study was designed to investigate the effects of moderate dose to very high dose methotrexate on methionine and total homocysteine as reflections of methotrexate induced intracellular events. Methionine and total homocysteine we...

Impaired transport of methotrexate (MTX) is a common resistance mechanism of tumor cells to this drug. Trimetrexate (TMTX), a second-generation folate antagonist, is still active against MTX-transport-resistant cells because it enters cells by passive diffusion and does not use the reduced folate transport system for cell entry. Therefore, although leucovorin (LV) protects MTX-sensitive cells f...

Methotrexate (MTX)-resistant mutants of the parasitic protozoan Leishmania have been used as models for the mechanism and genetic basis of drug resistance in trypanosomatids and other cells. Three resistance mechanisms to MTX, a dihydrofolate reductase inhibitor, have been described in Leishmania: decreased uptake and accumulation of MTX via the folate/MTX transporter, amplification and overexp...

Transfection of multidrug resistance proteins (MRPs) MRP1 and MRP2 in human ovarian carcinoma 2008 cells conferred a marked level of resistance to short-term (1-4 h) exposure to the polyglutamatable antifolates methotrexate (MTX; 21-74-fold), ZD1694 (4-138-fold), and GW1843 (101-156-fold). Evidence for MRP-mediated antifolate efflux relies upon the following findings: (a) a 2-3.3-fold lower acc...

objective: to evaluate the plasma creatine phosphokinase (cpk) level after injection of methotrexate (mtx) as a predictor of treatment success in ectopic pregnancy (ep). materials and methods: one hundred women treated with single dose of methotrexate for ectopic pregnancy were evaluated in a prospective study, for cpk and ß-subunit of human chorionic gonadotropin (ß-hcg) levels. they received ...

Background: Methotrexate is an anti-metabolite drug and one of the folic acid analog that it can play an important and functional role in the treatment of many malignancies and inflammatory diseases. However, the development of petechiae (maculopapular rash) is a very rare complication. Case Presentation: The patient was a 77 years old woman, Aryan race, who was known a case of severe and prog...

Methotrexate reduces intracellular pools of 5-methyltetrahydrofolate and could result in reduced conversion of homocysteine to methionine by methionine synthetase. This study was designed to investigate the effects of moderate dose to very high dose methotrexate on methionine and total homocysteine as reflections of methotrexate induced intracellular events. Methionine and total homocysteine we...