Neurotoxidad inducida por ifosfamida / Ifosfamide-induced neurotoxicity

Introducción: La ifosfamida es un agente alquilante utilizado para el tratamiento de enfermedades oncohematológicas. Entre sus eventos adversos agudos se encuentra la neurotoxicidad. Esta puede presentarse desde el inicio de la infusión hasta tres días después. El tratamiento consiste en suspender la administración y asegurar una adecuada hidratación. Objetivo: Describir eventos neurológicos asociados al uso de ifosfamida en pacientes pediátricos con enfermedades oncohematológicas. Materiales y métodos: Estudio observacional, descriptivo, retrospectivo y transversal. Los datos se obtuvieron de historias clínicas de pacientes internados en el Hospital Garrahan que infundieron ifosfamida y desarrollaron síntomas neurológicos. Se analizaron edad, diagnóstico de base, dosis de ifosfamida, síntomas neurológicos y su relación con la infusión, tratamiento instaurado, exámenes complementarios y posibles factores de riesgo asociados. Resultados: Se registraron un total de catorce eventos neurológicos en doce pacientes, sin diferencia de sexo, con una mediana de edad de 9,5 años. La enfermedad de base más prevalente fue osteosarcoma. Las convulsiones fueron el síntoma más frecuente (50%), seguido de somnolencia y paresias. La combinación de ifosfamida y etopósido con/sin carboplatino se asoció en un 36% cada uno. El 64% desarrolló neurotoxicidad dentro de las primeras cuatro horas. Ningún paciente presentó alteraciones en los exámenes complementarios. Todos presentaron recuperación ad integrum. Conclusión: Este estudio brinda información acerca del tiempo de aparición de esta complicación, lo cual facilitará su detección precoz y tratamiento oportuno (AU)

Introduction: Ifosfamide is an alkylating agent used for the treatment of cancer. Among its acute adverse events is neurotoxicity. This can occur from the beginning of the infusion up to three days afterwards. Treatment consists of discontinuing administration and ensuring adequate hydration. Objective: To describe neurological events associated with the use of ifosfamide in children with cancer. Materials and methods: Observational, descriptive, retrospective, and cross-sectional study. Data were obtained from clinical records of patients admitted to the Garrahan Hospital who received ifosfamide infusion and developed neurological symptoms. Age, baseline diagnosis, ifosfamide dose, neurological symptoms and their relationship with the infusion, treatment, complementary tests, and possible associated risk factors were analyzed. Results: A total of fourteen neurological events were recorded in twelve patients, without difference in sex and with a median age of 9.5 years. The most prevalent underlying disease was osteosarcoma. Seizures were the most frequent symptom (50%), followed by drowsiness and paresis. The combination of ifosfamide and etoposide with/without carboplatin was associated in 36% each. Sixty-four percent developed neurotoxicity within the first four hours. None of the patients presented with abnormalities in the complementary examinations. All recovered ad integrum. Conclusion: This study provides information about the time of onset of this complication, which will facilitate its early detection and timely treatment (AU)

DNA from protozoan parasites Babesia bovis, Trypanosoma cruzi, and T. brucei is mitogenic for B lymphocytes and stimulates macrophage expression of interleukin-12, tumor necrosis factor alpha, and nitric oxide.

The activation of innate immune responses by genomic DNA from bacteria and several nonvertebrate organisms represents a novel mechanism of pathogen recognition. We recently demonstrated the CpG-dependent mitogenic activity of DNA from the protozoan parasite Babesia bovis for bovine B lymphocytes (W. C. Brown, D. M. Estes, S. E. Chantler, K. A. Kegerreis, and C. E. Suarez, Infect. Immun. 66:5423-5432, 1998). However, activation of macrophages by DNA from protozoan parasites has not been demonstrated. The present study was therefore conducted to determine whether DNA from the protozan parasites B. bovis, Trypanosoma cruzi, and T. brucei activates macrophages to secrete inflammatory mediators associated with protective immunity. DNA from Escherichia coli and all three parasites stimulated B-lymphocyte proliferation and increased macrophage production of interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO). Regulation of IL-12 and NO production occurred at the level of transcription. The amounts of IL-12, TNF-alpha, and NO induced by E. coli and protozoal DNA were strongly correlated (r2 > 0.9) with the frequency of CG dinucleotides in the genome, and immunostimulation by DNA occurred in the order E. coli > or = T. cruzi > T. brucei > B. bovis. Induction of inflammatory mediators by E. coli, T. brucei, and B. bovis DNA was dependent on the presence of unmethylated CpG dinucleotides. However, at high concentrations, E. coli and T. cruzi DNA-mediated macrophage activation was not inhibited following methylation. The recognition of protozoal DNA by B lymphocytes and macrophages may provide an important innate defense mechanism to control parasite replication and promote persistent infection.

Trypanosoma cruzi tubulin eliminated in the urine of the infected host.

In previous studies we have identified and characterized an 80-kDa Trypanosoma cruzi urinary antigen (UAg) eliminated during acute infection. Polyclonal antibodies raised against this antigen revealed by western blotting and immunoprecipitation analyses showed the existence of another antigenic component of 50-55 kDa in the UAg preparation. The antiserum was also used for screening of a T. cruzi expression library. Sequencing of inserts from selected cDNA clones showed high homology with the 3' end of the T.cruzi beta-tubulin gene sequence encoding for the C-terminus of the protein. The presence of T. cruzi tubulin in the UAg was confirmed by immunoprecipitation of a 50-55-kDa protein from 125I-labeled UAg with monoclonal antibodies (MAbs) to human alpha/beta-tubulin. Interestingly, MAbs recognized radiolabeled T. cruzi tubulin eliminated in the urine of infected mice 24 hr postinoculation of [35S]methionine-labeled viable trypomastigotes. Tubulin found in the urine proved to be of T. cruzi origin because this protein could not be identified in urinary specimens from uninfected animals or mice acutely infected with Leishmania infantum or Toxoplasma gondii. We conclude that tubulin is one of the parasite antigens eliminated in the urine of T. cruzi-infected hosts. This finding may be used to develop a noninvasive procedure for early diagnosis of Chagas' disease.

An iron-binding Trypanosoma cruzi urinary antigen.

An 80-kDa Trypanosoma cruzi urinary antigen (UAg) was affinity-purified from the urine of infected dogs. We demonstrated that UAg is structurally and functionally related to proteins belonging to the transferrin family, as shown by amino acid sequence and iron binding experiments. Nevertheless, monoclonal antibodies raised against UAg specifically and selectively recognized this parasite's circulating antigen. The existence of an 80-kDa T. cruzi antigen co-migrating with UAg could be confirmed when epimastigotes were metabolically labelled with [35S] methionine and then immunoprecipitated with the above mentioned antibodies. We conclude that UAg is an iron-binding T. cruzi component eliminated in the urine of the infected host.

Effect of anti-gamma-interferon and anti-interleukin-4 administration on the resistance of mice against infection with reticulotropic and myotropic strains of Trypanosoma cruzi.

We studied the effect of in vivo administration of anti-gamma-IFN and anti-IL-4 monoclonal antibodies on the resistance of mice against myotropic and reticulotropic strains of Trypanosoma cruzi. Anti-gamma-IFN treatment augmented the susceptibility of mice when infected with the reticulotropic RA and Tulahuén strains of T. cruzi but did not alter the course of infection with the myotropic CA-I strain of the parasite. In vivo administration of anti-IL-4 enhanced the resistance of mice when infected with either Tulahuén or RA strains but did not affect the course of parasitemia when infected with CA-I. The possible biological relevance of these observations is discussed.