Methotrexate use, not interleukin 33, is associated with lower carotid intima-media thickness in patients with rheumatoid arthritis

Abstract Background: Rheumatoid arthritis is a risk factor for early mortality due to cardiovascular disease. Interleukin-33 appears to protect against the development of atherosclerosis. The purpose of this study was to investigate the relationship between serum levels of interleukin-33 and its soluble receptor with the presence of subclinical carotid atherosclerosis in rheumatoid arthritis patients. Methods: Rheumatoid arthritis patients without atherosclerotic disease were subjected to clinical and laboratory assessments, including carotid ultrasound. Interleukin-33 and its soluble receptor serum levels were measured by ELISA. Results: 102 patients were included. The prevalence of carotid plaques was 23.5% and the median intima-media thickness was 0.7 mm. The median interleukin-33 and its soluble receptor concentration was 69.1 and 469.8 pg/ml. No association was found between serum interleukin-33 or its soluble receptor and intima-media thickness or plaque occurrence. Each 0.1 mm increase of intima-media thickness raised the odds of plaque occurrence by 5.3-fold, and each additional year of rheumatoid arthritis duration increased the odds of plaque occurrence by 6%. Each additional year in patients age and each one-point increase in the Framingham Risk Score were associated with a 0.004 mm and 0.012 mm increase in intima-media thickness. Methotrexate use was associated with a 0.07 mm reduction in intima-media thickness. Conclusions: Interleukin-33 and its soluble receptor were not associated with subclinical atherosclerosis. Traditional risk factors for atherosclerosis and rheumatoid arthritis duration were associated with intima-media thickness and plaque occurrence; methotrexate use was associated with a lower intima-media thickness.

Methotrexate changes the testicular tyrosine phosphorylated protein expression and seminal vesicle epithelia of adult rats / El metotrexato cambia la expresión de la proteína testicular-tirosina fosforilada y el epitelio vesicular seminal en ratas adultas

Methotrexate (MTX) is commonly used as a chemotherapy agent and immune system suppressant but its adverse effect on male reproductive system is still limited. This study aimed to investigate the effect of MTX on structure and functional proteins of testis and seminal vesicle. Adult male rats were divided into control and MTX groups (n =12). In 30 experimental days, the treated animals were injected with MTX (tail i.v., 75 mg/KgBW) at days 8 and 15. Then, the reproductive parameters and histology of both groups were examined. Thickness of seminal seminal vesicle epithelia was analyzed. Also, the expressions of testicular tyrosine phosphorylated proteins and steroidogenic acute regulatory (StAR) protein were investigated. The results showed that MTX could significantly decrease epididymal sperm concentration. In addition, the germ cell degeneration, increased spaces of interstitial tissues, and low epididymal sperm mass density were observed in MTX group. The thickness of seminal vesicle epithelia in MTX group was significantly lower than that of control group. Moreover, the intensity of testicular phosphorylated proteins of 31, 32, 72, and 85 kDas was significantly increased while of 42 and 47 kDas in MTX group was decreased as compared to control. The expression of testicular StAR protein in MTX group was also significantly decreased as compared to the control. In conclusion, MTX affects testicular and seminal tissues and changes testicular functional proteins in adult rats.

El metotrexato (MTX) se usa comúnmente como agente de quimioterapia y supresor del sistema inmunitario, pero su efecto adverso en el sistema reproductor masculino sigue siendo limitado. Este estudio tuvo como objetivo investigar el efecto del MTX sobre la estructura y las proteínas funcionales del testículo y la vesícula seminal. Ratas macho adultas se dividieron en grupos control y grupo con MTX (n = 12). En 30 días experimentales, a los animales tratados se les inyectó MTX (cola i.v., 75 mg / KgBW) los días 8 y 15. Luego, se examinaron los parámetros reproductivos y la histología de ambos grupos. Se analizó el espesor del epitelio de la vesícula seminal. Además, se investigaron las expresiones de la proteína tirosina testicular fosforilada y de la proteína reguladora aguda esteroidogénica (StAR). Los resultados mostraron que el MTX podría disminuir significativamente la concentración de espermatozoides epididimarios. Además, se observó la degeneración de las células germinales, el aumento de los espacios de los tejidos intersticiales y la baja densidad de masa del espermatozoide epididimal en el grupo de MTX. El grosor del epitelio de la vesícula seminal en el grupo MTX fue significativamente menor que el del grupo control. Además, la intensidad de las proteínas testiculares fosforiladas de 31, 32, 72 y 85 kDas aumentó significativamente, mientras que la de 42 y 47 kDas en el grupo MTX disminuyó en comparación con el control. La expresión de la proteína StAR testicular en el grupo MTX también se redujo significativamente en comparación con el control. En conclusión, el MTX afecta los tejidos testiculares y seminales y cambia las proteínas funcionales testiculares en ratas adultas.

Methotrexate associated to lipid core nanoparticles improves cardiac allograft vasculopathy and the inflammatory profile in a rabbit heart graft model

Coronary allograft vasculopathy is an inflammatory-proliferative process that compromises the long-term success of heart transplantation and has no effective treatment. A lipid nanoemulsion (LDE) can carry chemotherapeutic agents in the circulation and concentrates them in the heart graft. The aim of the study was to investigate the effects of methotrexate (MTX) associated to LDE. Rabbits fed a 0.5% cholesterol diet and submitted to heterotopic heart transplantation were treated with cyclosporine A (10 mg·kg-1·day-1 orally) and allocated to treatment with intravenous LDE-MTX (4 mg/kg, weekly, n=10) or with weekly intravenous saline solution (control group, n=10), beginning on the day of surgery. Animals were euthanized 6 weeks later. Compared to controls, grafts of LDE-MTX treated rabbits showed 20% reduction of coronary stenosis, with a four-fold increase in vessel lumen and 80% reduction of macrophage staining in grafts. Necrosis was attenuated by LDE-MTX. Native hearts of both LDE-MTX and Control groups were apparently normal. Gene expression of lipoprotein receptors was significantly greater in grafts compared to native hearts. In LDE-MTX group, gene expression of the pro-inflammatory factors tumor necrosis factor-α, monocyte chemoattractant protein-1, interleukin-18, vascular cell adhesion molecule-1, and matrix metalloproteinase-12 was strongly diminished whereas expression of anti-inflammatory interleukin-10 increased. LDE-MTX promoted improvement of the cardiac allograft vasculopathy and diminished inflammation in heart grafts.

Metotrexate como inductor en la producción de citocinas proinflamatorias en células epiteliales / Methotrexate as inducer of proinflammatory cytokines by epithelial cells

El metotrexate (MTX) es uno de los medicamentos frecuentemente utilizados en el cáncer infantil señalándose además, como agente citotóxico de la mucosa bucal, que puede desencadenar el proceso inflamatorio e incremento de la vascularidad en los tejidos epiteliales durante las fases iniciales de la mucositis oral. El presente trabajo tiene como objetivo determinar la producción de citocinas proinflamatorias IL-1b, IL-6 y TNF-a en cultivos de células epiteliales tratadas con MTX. Se realizaron cultivos de células epiteliales de laringe humana obtenidas de la línea celular Hep-2, con diferentes dosis de MTX en distintos tiempos de incubación, y a su vez se analizó la citotoxicidad del fármaco mediante el ensayo colorimétrico, el cual se basa en la reducción metabólica del bromuro de 3-(4,5- dimetiltiazol-2-ilo)-2,5-difeniltetrazol (MTT), y la producción de citocinas proinflamatorias mediante el ensayo inmuno enzimático indirecto (ELISA). En cuanto a los resultados se observó, que los cultivos de células Hep-2 presentaron aumento en la producción de las citocinas proinflamatorias a las 72 horas al utilizar las dosis de 0.32µM MTX. Estos resultados sugieren que la dosis y el tiempo de exposición del MTX alteran la fisiología de las células epiteliales humanas, lo cual podrían desempeñar un papel importante durante las fases de iniciación y de desarrollo de la mucositis oral.

Methotrexate (MTX), a drug commonly used in childhood cancer, has also been indicated as a cytotoxic agent of the oral mucosa, which can trigger the inflammatory process and increase the vascularity of epithelial tissues during the early stages of oral mucositis. The aim of this study was to determine the production of proinflammatory cytokines IL-1b, IL-6 y TNF-a in epithelial cell cultures treated with MTX. Epithelial cells of human larynx, obtained from the cell line Hep-2, were cultured with different doses of MTX during different incubation times. The drug cytotoxicity was analyzed by means of the colorimetric test, which is based on the metabolic reduction of the bromide of 3-(4, 5-dimetiltiazol-2-ilo)-2,5-difeniltetrazol (MTT); and the proinflammatory cytokines production by the test enzyme-linked immunosorbent assay (ELISA). Cultures of HEp-2 cells showed increased production of proinflammatory cytokines at 72 hours with 0.32µM of MTX. These results suggest that depending on the dose and exposure time, MTX alters the physiology of human epithelial cells, which may play an important role during the phases of initiation and development of oral mucositis.

Fraturas do fêmur proximal no idoso: estudo de custo da doença sob a perspectiva de um hospital público no Rio de Janeiro, Brasil / Hip fractures in the elderly: cost of illness study in a public hospital perspective, Rio de Janeiro, Brazil

O artigo visa a estimar o custo direto médico do tratamento hospitalar de pacientes idosos com fraturas de fêmur proximal, no Hospital Municipal Lourenço Jorge, na cidade do Rio de Janeiro. Estudo observacional, prospectivo, para estimar a utilização de recursos e custos diretos médicos associados à hospitalização por fratura de fêmur proximal em idosos, em 2007 e 2008, sob a perspectiva do prestador de serviços. Foi utilizado um instrumento de coleta de dados através do qual foram registrados recursos identificados na revisão prospectiva dos prontuários. Aos recursos utilizados foram atribuídos custos em reais (R$) baseando-se em valores do ano 2010. Foram realizadas análises descritivas dos custos e utilização de recursos, bem como avaliada a associação de variáveis clínicas e demográficas com o custo final observado. Foram incluídos 82 pacientes, 81,7 por cento do sexo feminino, idade média de 76,96 anos, hospitalização média de 12,66 dias. A mediana de custo por paciente foi de R$ 3.064,76 (IC95 por cento: 2.817,63 a 3.463,98). Hospitalização clínica e procedimento cirúrgico foram responsáveis por 65,61 por cento e 24,94 por cento dos custos, respectivamente. Pacientes submetidos ao tratamento cirúrgico até o quarto dia de hospitalização apresentaram mediana de custos menor do que pacientes submetidos após o quarto dia (R$ 2.136,31 e R$ 3.281,45, p<0,00001). Observou-se também diferença significativa nos custos finais por tipo de procedimento cirúrgico realizado. O custo do tratamento das fraturas de fêmur proximal no idoso foi significativamente maior nos pacientes submetidos à cirurgia após o quarto dia de hospitalização. Hospitalização clínica e procedimento cirúrgico foram os principais componentes do custo final observado.

This paper aims to assess direct medical costs associated to hospital treatment of hip fractures in the elderly in the Municipal Hospital Lourenço Jorge (HMLJ), Rio de Janeiro. Observational, prospective study to assess resource utilization and direct medical costs associated to elderly hip fracture hospitalization in 2007 and 2008, under the health care provider perspective. A standard data collection instrument was used to register identified resources during prospective medical charts review. The resource utilization was converted into Brazilian Real (R$), based on 2010 prices. Descriptive analysis of costs and resource utilization and their association with clinical and demographic variables were performed. Eighty two patients were included, 81.7 percent female, mean age of 76.96 years, hospitalization mean time of 12.66 days. Median total costs per patient were R$ 3,064.76 (IC95 percent: 2,817.63 - 3,463.98). Clinical hospitalization and surgical procedure were responsible for 65.61 percent and 24.94 percent of costs, respectively. Median costs for patients submitted to surgical procedure until the fourth day of hospitalization were lower than median costs for patients submitted after the fourth day (R$ 2,136.45 and R$ 3,281.45, respectively, p<0.00001). A significant difference in average costs per type of surgical procedure was also observed. Cost associated to inpatient treatment of hip fractures in the elderly was higher in patients who performed surgery after the fourth day of hospitalization. Clinical hospitalization and surgical procedure were the main cost components observed.

Farmacogenómica del metotrexate: estrategia para una terapéutica más individualizada en pacientes con artritis reumatoide / Pharmacogenomics of methrotexate: a strategy for a customized therapeutic scheme for patients with rheumatoid arthritis

La artritis reumatoide es una enfermedad reumática frecuente en nuestro país. El metotrexate es uno de los fármacos más utilizados en este padecimiento, sin embargo, un porcentaje alto de pacientes suspende el tratamiento debido a los efectos adversos. Varios estudios han analizado los polimorfismos C677T y A1298C del gen de la enzima metilentetrahidrofolato reductasa (MTHFR) en pacientes con artritis reumatoide en relación con la eficacia, efectos colaterales y toxicidad que presentan con el metotrexate. Mediante técnicas moleculares factibles en nuestro país, como la PCR-RFLP, es posible determinar el polimorfismo MTHFR C677T, cuya frecuencia alélica en México es alta, en pacientes con artritis reumatoide con el fin de identificar a quienes tendrán mayor riesgo para presentar toxicidad y efectos colaterales y a quienes responderán mejor al metotrexate, permitiendo así un tratamiento más individualizado, objetivo de la farmacogenómica..

Rheumatoid arthritis (RA) is a common rheumatic disease in Mexico. Methotrexate (MTX) is a drug frequently used in the treatment of this disease. However, treatment discontinuation due to side effects is also common. Inter-individual differences in effectiveness and occurrence of side effects in RA patients treated with MTX (RA-MTX) have been reported. Several studies analyzed the presence of MTHFR C677T and A1298C polymorphisms in RA-MTX patients associated with effectiveness, side effects and toxicity. Given the high frequency of the MTHFR C677T polymorphism in Mexico, it is of utmost interest to determine the allelic and genotypic frequency of these polymorphisms in patients with RA-MTX. The use of molecular techniques, feasible in our country, such as PCR/RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) can allow us to identify these MTHFR genotypes among RA-MTX patients in order to target patients at risk of developing drug toxicity, side effects or better MTX efficacy. The ultimate goal is to develop individualized treatment, as promised by the field of pharmacogenomics.

Mecanismos de acción de los fármacos inmunosupresores / Mechanisms of action of immunosuppressive drugs

Durante los últimos 50 años, muchos fármacos inmunosupresores han sido descritos, y sus mecanismos de acción se pueden dividir en: Reguladores de la expresión génica; Agentes alquilantes; Inhibidores de novo de la síntesis de purinas y pirimidinas, e Inhibidores de quinasas y fosfatasas. Los glucocorticoides ejercen su acción inmunosupresora y antiinflamatoria principalmente mediante la inhibición de la expresión de los genes de interleuquina-2 (IL-2) y otros mediadores. Los metabolitos derivados de Ciclofosfamida alquilanizan las bases de ADN y suprimen preferentemente la respuesta inmune (RI) mediada por linfocitos B (LB). Por su parte, el Metotrexato reprime las respuestas inflamatorias liberando adenosina; ésta induce la apoptosis de LT activos e inhibe la síntesis de purinas y pirimidinas. La Azatioprina inhibe varias enzimas implicadas en la síntesis de purinas, mientras que el Ácido micofenólico inhibe la inosina-monofosfato deshidrogenasa, con lo que agota los nucleótidos derivados de guanosina, induciendo la apoptosis de LT activados. Un metabolito de la Leflunomida suprime la dihidro-orotatedeshidrogenada y, consecuentemente, la síntesis de nucleótidos pirimidínicos. La Ciclosporina y el Tacrolimus inhiben la actividad de la Calcineurina, con lo que se suprime la producción de IL-2 y de otras citoquinas. Además, estos compuestos han demostrado bloquear las vías de señalización JNK y p38, activadas por el reconocimiento de antígenos en LT. Por el contrario, la Rapamicina inhibe quinasas celulares necesarias para el ciclo celular y las respuestas a IL-2; también induce la apoptosis de LT activos. Un futuro promisorio es derivado de la aplicación de fármacos inmunosupresores biológicos. El papel y mecanismos de acción de ellos serán discutidos aquí.

During the past 50 years, many immunosuppressive drugs have been described and their mechanisms of action can be organized in: Regulators of gene expression; Alkylating agents; Inhibitors of the novo purine and pyrimidine synthesis, and Inhibitors of kinases and phosphatases. Glucocorticoids exert immunosuppressive and anti-inflammatory activity mainly by inhibiting the expression of interleukin-2 (IL-2) genes and other mediators. Cyclophosphamide metabolites alkylate DNA bases and preferentially suppress immune responses mediated by B-lymphocytes. Methotrexate suppresses inflammatory responses through the release of adenosine; they suppress immune responses by inducing the apoptosis of activated T-lymphocytes and inhibit the synthesis of both purines and pyrimidines. Azathioprine metabolites inhibit several enzymes of purine synthesis. Mycophenolic acid inhibits inosine monophosphate dehydrogenase, thereby depleting guanosine nucleotides, inducing the apoptosis of activated T-lymphocytes. A Leflunomide metabolite inhibits dihydroorotate dehydrogenase, thereby suppressing pyrimidine nucleotide synthesis. Cyclosporine and Tacrolimus inhibit the phosphatase activity of Calcineurin, thereby suppressing the production of IL-2 and other cytokines. In addition, these compounds have recently been found to block the JNK and p38 signaling pathways triggered by antigen recognition in T-cells. In contrast, Rapamycin inhibits both kinases required for cell cycling and responses to IL-2; it also induces apoptosis of activated T-lymphocytes.A promising future is the application of biologic immunosuppressive drugs. We review their role and action mechanisms.

In vitro chemosensitivity profile of oral squamous cell cancer and its correlation with clinical response to chemotherapy.

CONTEXT: Oral cancers represent a disparate group of tumors with diverse clinical behavior and chemosensitivity profile. Currently, it is difficult to predict whether a tumor will respond to chemotherapy and which drug(s) will achieve the maximum clinical response. AIMS: To study in vitro chemosensitivity profile of oral cancers and to correlate the in vitro chemosensitivity of oral cancer to clinical response to chemotherapy. SETTINGS AND DESIGN: Prospective study in a tertiary cancer care center. METHODS AND MATERIAL: We prospectively studied the chemosensitivity profile of 57 untreated, advanced, unresectable oral cancers to cisplatin, methotrexate, 5-fluorouracil and their combinations by using histoculture drug response assay (HDRA) and correlated them to the clinical response to chemotherapy. STATISTICAL ANALYSIS USED: Chi Square test. RESULTS: Biopsy samples were successfully histocultured in 52/57 (91%) cases. Of these 52 evaluable patients, 47 had primary gingivo-buccal cancers and five had tongue / floor of mouth cancers. Based on the assay, 27 (52%) tumors were sensitive to cisplatin, 27 (52%) to methotrexate, 24 (46%) to 5-fluorouracil, 38 (73%) to combination of cisplatin and methotrexate and 36 (69%) to combination of cisplatin and 5-fluorouracil. Of these, 31 patients with good performance status received two cycles of chemotherapy using one or more of these test drugs. There was a significant correlation (p=0.03) between the in vitro chemosensitivity and the clinical response. Negative predictive value of the test was 80%, positive predictive value-69%, sensitivity-79% and specificity -71%. The overall accuracy of the assay was 74%. CONCLUSIONS: We found HDRA to be a fairly good predictor of chemo-response of oral cancer.

Evaluation of antimitotic activity of Rotula aquatica (Lour): a traditional herb used in treatment of cancer.

Rotula aquatica was extensively used by vaidyas (Ayurvedic practioners) in holistic treatment of cancer. In the present study, an attempt has been made to evaluate the antimitotic activity of R. aquatica. Preliminary antimitotic screening was done using Allium cepa root tip assay. The mitotic index of the root tips markedly decreased with increasing concentration of the aqueous extract. The different fractions obtained by successive extraction of R. aquatica using solvents of increasing polarity were also evaluated for their antimitotic activity. Tannins were isolated which showed a better activity than the non-tannin fraction. Experiments were also carried out with incorporation of folic acid in the aqueous extract. Folic acid inhibited the antimitotic activity of aqueous extract of R. aquatica in a dose dependent manner. The results obtained were compared with methotrexate--a known drug available in market as anti-cancer agent. The studies were extended to human cells using 3 pancreatic cancer cell lines, viz: HPAF-II, BxPC-3, and CAPAN-2. Extract of R. aquatica was found to be extremely effective in the prevention of cell proliferation of the pancreatic cancer cell lines. The phytochemical evaluation revealed presence of polyphenols (tannins) and steroids. A HPTLC fingerprinting was developed and studied. Two compounds were isolated and subjected to spectral studies like UV, IR and mass spectrums. The empirical formula was derived by considering this data with elemental analysis of the compounds.

Papulosis linfomatoide / Lymphomatoid papulosis

La papulosis linfomatoide es una entidad poco frecuente caracterizada por ser una erupción clínicamente benigna histológicamente maligna. Presentamos un caso de Papulosis Linfomatoide clásico no asociado a linfoma. Fue tratado con dosis bajas de metotrexato el cual fue muy efectivo y bien tolerado.

Papulosis linfomatoide / Lymphomatoid papulosis

La papulosis linfomatoide es una entidad poco frecuente caracterizada por ser una erupción clínicamente benigna histológicamente maligna. Presentamos un caso de Papulosis Linfomatoide clásico no asociado a linfoma. Fue tratado con dosis bajas de metotrexato el cual fue muy efectivo y bien tolerado.

Artropatía psoriática / Psoriatic arthropathy

El propósito fue analizar 18 casos de artropatía psoriática que tuvieran controles y tratamiento por lo menos de seis meses, principalmente con metotrexate. Nueve casos fueron hombres y nueve mujeres, con una edad promedio de 43,1 años. En quince el compromiso fue articular periférico y en uno de la columna vertebral. La mayoría evolucionó con oligoartritis. En cuanto a exámenes, el hemograma que se practicó en catorce pacientes, demostró anemia en seis leucocitosis en tres y linfopenia en tres. Dieciseis se trataron con metotrexate unido a corticoides o AINES. La evolución fue buena en trece, regular en dos y mala en uno. En todos los casos las transaminasas estuvieron en límites normales. Como conclusión, el metotrexate junto a corticoides o AINES es una buena terapia en el tratamiento de la artropatía psoriática, con muy buena tolerancia digestiva y hepática

Tratamiento médico del embarazo cervical: descripción de tres casos clínicos tratados con metrotexato sistémico / Medical treatment of the cervical pregnancy: description of 3 clinical cases treated with systemic methotrexate

Se presentan tres casos clínicos de embarazo cervical diagnosticados ecográficamente y tratados en forma conservadora, en dos pacientes con una sola dosis de 100 mg de metrotexato i.m. y en un tercer paciente con una sola dosis de 50 mg de metrotexato i.m. Los tres casos evolucionaron favorablemente no presentándose complicaciones ni toxicidad debido al metrotexato sistémico, realizándose su seguimiento posterior fundamentalmente en forma clínica y ecográfica, y por medio de niveles sanguíneos de subunidad beta hCG. Se revisa la literatura nacional y extranjera con especial énfasis en el tratamiento conservador con metrotexato del embarazo cervical

Artritis reumatoide de inicio reciente tratada con metotrexato, tres días por semana / Early rheumatoid arthritis treated with a weekly three time methotrexate dosage

Estudiamos 52 pacientes con artritis reumatoide (AR) de menos de un año de evolución según su propia referencia, la mayoría en clase funcional II, sin manifestaciones extraarticulares serias, tratadas con esquema de metotrexato (MTX) oral en días alternos (3 dosis/semanas, un antiinflamatorio no esteroide oral matinal y paracetamol en monodosis nocturna). Ninguno recibió esteroides o algún otro inductor de remisión. La cuenta de articulaciones dolorosas (inicial: 51; final: 4) y la rigidez matinal se redujo significativamente al momento de efectuar la valoración al fin de un año de observación. El factor reumatoide no se modificó y sólo en pacientes hubo elevación de las enzimas hepáticas. Consideramos que el MTX en este esquema posológico reduce la necesidad de medicación sintomática concomitante

Mejoría en el pronóstico de la leucemia linfoblástica aguda en niños de un país en desarrollo: resultados del protocolo nacional chileno PINDA 87 / Improved outcome for acute lymphoblastic leukemia in children of a developing country: results of the chilean national trial PINDA 87

Un grupo oncológico pediátrico nacional, PINDA, reporta el primer protocolo prospectivo, no randomizado, para tratamiento de la leucemia linfoblástica (LLA), usando una versión modificada del protocolo de Berlín-Frankfurt-Munster (LLA BFM 86). Los objetivos de este estudio fueron clasificar inmunofenotipos, disminuir radioterapia de cráneo y comprobar si este protocolo podía mejorar la sobrevida de nuestros pacientes. Procedimiento: desde junio 1987 a junio 1992 se registraron 444 pacientes, no seleccionados; de ellos 425 fueron evaluables. La terapia fue estratificada según riesgo: riesgo bajo (RB), riesgo alto (RA) y riesgo muy alto (RMA). Los pacientes en RB y RA recibieron inducción con protocolo I, consolidación con protocolo M (RMA usó protocolo E), reinducción con protocolo II y mantención. Todos recibieron tratamiento de prefase con prednisona oral y metotrexato (MTX) intratecal. Radioterapia de cráneo solo en RA y RMA (12-18 Gy). Los siguientes cambios se introdujeron al protocolo LLA BFM 86: en protocolo M 1 g/m² en vez de 5 g/m²; en protocolo E, 1 g/m² de citarabina en vez de 2 g/m², la mitoxantrona e ifosfamida fueron sustituidas por teniposido y ciclofosfamida. Resultados: inmunofenotipo: LLA común 67,4 por ciento, LLA proB 14 por ciento, LLA T 10 por ciento, LLA preB 4,3 por ciento. La frecuencia de sobrevida libre de eventos (SLE) global a 5 años fue 60 por ciento ñ 2 por ciento error standard; según riesgo fue: RB 75 por ciento, RA 62 por ciento, RMA 28 por ciento con una mediana de seguimiento de 6,5 años (rango 4,5 - 9,5 años). La incidencia acumulada de recaída en sistema nervioso central SNC fue 5,4 por ciento. Conclusión: hemos tenido éxito en realizar un estudio a nivel nacional. Nuestra estrategia para adaptar el protocolo BFM fue efectiva para mejorar la SLE. La distribución por fenotipos es similar a otras series

Collateral methotrexate resistance in cisplatin-selected murine leukemia cells

Resistance to anticancer drugs is a major cause of failure of many therapeutic protocols. A variety of mechanisms have been proposed to explain this phenomenon. The exact mechanism depends upon the drug of interest as well as the tumor type treated. While studying a cell line selected for its resistance to cisplatin we noted that the cells expressed a >25,000-fold collateral resistance to methotrexate. Given the magnitude of this resistance we elected to investigate this intriguing collateral resistance. From a series of investigations we have identified an alteration in a membrane protein of the resistant cell as compared to the sensitive cells that could be the primary mechanism of resistance. Our studies reviewed here indicate decreased tyrosine phosphorylation of a protein (molecular mass = 66) in the resistant cells, which results in little or no transfer of methotrexate from the medium into the cell. Since this is a relatively novel function for tyrosine phosphorylation, this information may provide insight into possible pharmacological approaches to modify therapeutic regimens by analyzing the status of this protein in tumor samples for a better survival of the cancer patients