MethotrexatePolyglutamic AcidAntirheumatic AgentsFolic Acid AntagonistsTetrahydrofolate DehydrogenaseArthritis, RheumatoidAminopterinAntimetabolites, AntineoplasticLeukemia L1210Reduced Folate Carrier ProteinTrimetrexateFolic AcidDrug Therapy, CombinationTreatment Outcomegamma-Glutamyl HydrolaseLeucovorinTetrahydrofolatesAbortifacient Agents, NonsteroidalCyclophosphamideDrug ResistanceImmunosuppressive AgentsAntineoplastic Combined Chemotherapy ProtocolsDrug Administration ScheduleSulfasalazineVincristinePrecursor Cell Lymphoblastic Leukemia-LymphomaDeoxyuridineDermatologic Agents6-MercaptopurinePregnancy, EctopicFluorouracilFormyltetrahydrofolatesFolate Receptors, GPI-AnchoredDose-Response Relationship, DrugDoxorubicinPhosphoribosylaminoimidazolecarboxamide FormyltransferasePrednisoneInjections, SpinalOsteosarcomaCytarabineLeukemia, LymphoidThymidylate SynthaseHydroxychloroquineCentral Nervous System NeoplasmsPregnancy, TubalSarcoma 180PsoriasisPteroylpolyglutamic AcidsIsoxazolesAsparaginaseRemission InductionGestational Trophoblastic DiseaseBiological TransportProbenecidHydroxymethyl and Formyl TransferasesTime FactorsDouble-Blind MethodCombined Modality TherapyMucositisAntibodies, MonoclonalAdministration, OralNucleotide DeaminasesCarcinoma, Ehrlich TumorVinblastineArthritis, JuvenileArthritis, PsoriaticAntineoplastic AgentsSeverity of Illness IndexCisplatinTrophoblastic NeoplasmsLeukemia L5178Breast NeoplasmsSurvival AnalysisHypoxanthinesAnti-Inflammatory AgentsKinetics