ABSTRACT
BACKGROUND: During the last few years it has been shown in several laboratories that Celecoxib (Cx), a non-steroidal anti-inflammatory agent (NSAID) normally used for pain and arthritis, mediates antitumor and antiangiogenic effects. However, the effects of this drug on a tumor cell line resistant to chemotherapeutical drugs used in cancer have not been described. Herein we evaluate the angiogenic and antitumor effects of Cx in the development of a drug-resistant mammary adenocarcinoma tumor (TA3-MTXR). RESULTS: Cx reduces angiogenesis in the chick embryonic chorioallantoic membrane assay (CAM), inhibits the growth and microvascular density of the murine TA3-MTXR tumor, reduces microvascular density of tumor metastases, promotes apoptosis and reduces vascular endothelial growth factor (VEGF) production and cell proliferation in the tumor. CONCLUSION: The antiangiogenic and antitumor Cx effects correlate with its activity on other tumor cell lines, suggesting that Prostaglandins (PGs) and VEGF production are involved. These results open the possibility of using Celecoxib combined with other experimental therapies, ideally aiming to get synergic effects.
Subject(s)
Animals , Female , Chick Embryo , Mice , Pyrazoles/pharmacology , Sulfonamides/pharmacology , Breast Neoplasms/drug therapy , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Apoptosis/drug effects , Drug Resistance, Neoplasm/drug effects , Lung Neoplasms/secondary , Neovascularization, Pathologic/drug therapy , Pyrazoles/administration & dosage , Sulfonamides/administration & dosage , Breast Neoplasms/pathology , Drug Screening Assays, Antitumor , Chickens , In Situ Nick-End Labeling , Angiogenesis Inhibitors/pharmacology , Cell Line, Tumor , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Chorioallantoic Membrane , Cell Proliferation/drug effects , CelecoxibABSTRACT
Angiogenesis is a complex multi-step process of neovascularization arising from preexisting blood vessels whose generation is regulated by pro- and anti-angiogenic factors. Both Trypanosoma cruzi calreticulin (TcCRT) and its human counterpart (HuCRT) are antiangiogenic. This is the first report where the TcCRT and HuCRT anti-angiogenic properties are compared in vivo. In the chick embryonic chorioallantoid membrane assay (CAM) and at equimolar concentrations, TcCRT displayed significantly higher antiangiogenic activities than its human counterpart. LPS had marginal effects at the concentrations present in the recombinant protein preparations and the TcCRT antiangiogenic effects were largely inhibited by specific polyclonal antibodies, thus, reinforcing the fact that the observed TcCRT effects can be attributed to the parasite-derived molecule and not to the endotoxin. The antiangiogenic TcCRT effects correlate with its anti-tumor in vivo effects, as recently shown in our laboratory.
Subject(s)
Animals , Chick Embryo , Humans , Angiogenesis Inhibitors/pharmacology , Calreticulin/pharmacology , Trypanosoma cruzi/chemistry , Angiogenesis Inhibitors/isolation & purification , Calreticulin/isolation & purification , Neovascularization, PathologicABSTRACT
Tumor resistance to traditional cancer treatments poses an important challenge to modern science. Thus, angiogenesis inhibition is an important emerging cancer treatment. Many drugs are tested and corticosteroids have shown interesting results. Herein we investigate the effect on microvessel density, survival time and tumoral volume of mice with TA3-MTX-R tumors. Twenty six mice were inoculated with lxlO6 tumor cells, 4-5 days after injection, six mice were injected with PBS (group A) and twenty mice were treated with p-met (group B). All animals from Group A died on day 22. Group B was divided into Bl (treated discontinued) and B2 (treated daily) and observed until day 88. All mice were processed for histo-immunohistochemical analysis and the blood vessels were counted. A decrease in microvessel density and tumoral volume and longer survival times were observed in the treated group. We propose that the antiangiogenic p-met effect explains, at least partially, its tumor inhibitory properties. As an important perspective, we will experimentally combine these strategies with those recently described by us with regard to the important antiangiogenic-antitumor effects of Trypanosoma cruzi calreticulin. Since the molecular targets of these strategies are most likely different, additive or synergic effects are envisaged.
Subject(s)
Animals , Mice , Adenocarcinoma/drug therapy , Angiogenesis Inhibitors/therapeutic use , Betamethasone/therapeutic use , Neovascularization, Pathologic/drug therapy , Adenocarcinoma/blood supply , Drug Resistance, Multiple/drug effects , Drug Resistance, Neoplasm/drug effects , Mice, Inbred A , Microvessels/drug effects , Tumor Cells, Cultured , Tumor Burden/drug effectsABSTRACT
Trypanosoma cruzi calreticulin (TcCRT), described in our laboratory, retains several important functional features from its vertebrate homologues. We have shown that recombinant TcCRT inhibits the human complement system when it binds to the collagenous portion of C1q. The generation of classical pathway convertases and membrane attack complexes is thus strongly inhibited. In most T. cruzi-infected individuals, TcCRT is immunogenic and mediates the generation of specific antibodies. By reverting the C1q / TcCRT interaction, a parasite immune evasion strategy, these antibodies contribute to the host / parasite equilibrium. In an in vitro correlate of this situation, we show that the C1q / TcCRT interaction is inhibited by F(ab')2 polyclonal anti-TcCRT IgG fragments. It is therefore feasible that in infected humans anti-TcCRT antibodies participate in reverting an important parasite strategy aimed at inhibiting the classical complement pathway. Thus, membrane-bound TcCRT interacts with the collagenous portion C1q, and this C1q is recognized by the CD91-bound host cell CRT, thus facilitating parasite internalization. Based on our in vitro results, it could be proposed that the in vivo interaction between TcCRT and vertebrate C1q could be inhibited by F(ab')2 fragments anti-rTcCRT or against its S functional domain, thus interfering with the internalization process.
Subject(s)
Humans , Animals , Rabbits , Calreticulin/biosynthesis , Calreticulin/physiology , Calreticulin/immunology , Trypanosoma cruzi/isolation & purification , Trypanosoma cruzi/immunology , Complement Inactivating Agents/immunologyABSTRACT
Se presenta y analiza un protocolo en cirugía resectiva córtico-focal en epilepsias focales lesionales fármaco resistentes con lesión visible única a la neuroimagen, iniciado en el Instituto de Neurocirugía e Investigaciones Cerebrales Asenjo en 1990. Hasta la fecha se han operado 40 pacientes, 32 (80 porciento) niños, 8 (20 porciento) adultos. El área más frecuentemente intervenida fue el lóbulo temporal en 24 casos (60 porciento); la cirugía extratemporal se practicó en 16 pacientes, frontal en 11 y parietal en 5. No hubo mortalidad y 2 pacientes quedaron con secuela de defecto del campo visual
Subject(s)
Humans , Male , Female , Adolescent , Epilepsy, Frontal Lobe/surgery , Epilepsies, Partial/surgery , Temporal Lobe/surgery , Anticonvulsants/pharmacologyABSTRACT
En orina de ratones, infectados en forma aguda experimental con la cepa Tulahuén de T cruzi, se detectó señales radioautográficas en inmunodot, desarrollado con suero humano chagásico. En inmunoelectrotransferencia (IET) de orina murina concentrada, desarrollada con suero de humanos seropositivos, se detectó bandas de pesos moleculares 66, 56 (también presentes en orinas normales), 19, 12, 10 y 8 kDa. En orina de humanos seropositivos, sometida a IET contra una dilusión adecuada de sueros de estos mismos individuos se detectó bandas de 66, 56 (también presentes en orinas normales), 87, 46, 36 y 26 kDa. Hubo diferencias importantes en relación al número de éstos polipéptidos presentes en cada muestra. Curiosamente, si todos estos polipéptidos urinarios se enfrentan en IET a sueros humanos normales (seronegativos para T cruzi), son detectados en grado variable. este problema, a pesar de la sensibilidad de los ensayos usados y de la extensiva concentración a que se sometió los especímenes, cuestiona seriamente la especificidad del método, por lo cual el uso de orina como especímen para el diagnóstico expedito de Chagas, experimental y humano, no parece ser muy promisorio
Subject(s)
Mice , Chagas Disease/diagnosis , Trypanosoma cruzi/isolation & purification , Urine/parasitology , Antigens/isolation & purification , Immune Sera/analysisABSTRACT
Se realizó una caracterización e identificación de los antígenos de relevancia diagnóstica de fasciola hepatica empleando electroforesis en geles de poliacrilamida (SDS-PAGE), e inmunoelectrotransferencia. Se estudiaron tres grupos de antígenos: somáticos de fasciolas adultas (FhA), de ejemplares juveniles (FhJ) y productos de excreción-secreción (Fh E-S) del parásito. ellos fueron enfrentados a sueros de conejos hiperinmunes policlonales así como a sueros de 10 ovinos antes y después de ser expuestos a la infección natural, durante el período prepatente y patente de la misma. Se incluyeron como controles muestras de ovinos infectados con quistes hidatídicos y con Thysanosoma actinoides procedentes de áreas libres de fasciolosis. Empleando antígenos A y J se detectó una importante banda de 64 kDa así como bandas de 20-21, 26, 30-31 y 38 kDa con antígenos E-S al ser enfrentados a los sueron hiperinmunes de conejos. En el caso de los ovinos infectados se detectaron por su frecuencia y especificidad las fracciones de 16, 26-28, 35-36 y 56-58 kDa. Los polipéptidos de 26-28 y 35-38 kDa fueron reconocidos por nueve de los diez animales durante la etapa prepatente, siendo todos ellos detectados en la etapa patente de la fasciolosis. Estas fracciones se costituirían en las de mayor potencial diagnóstico de la fasciolosis ovina, siendo por lo tanto recomendable su posterior semipurificación
Subject(s)
Antigens, Helminth/isolation & purification , Fasciola hepatica/isolation & purification , Electrophoresis, Polyacrylamide Gel , Sheep/parasitologyABSTRACT
Se describen tres protocolos para la purificación, mediante cromatografía de alta presión (FPLC), de Tc45, un antígeno inmunogenéticamente definido de T. cruzi. Dos protocolos implicaron separaciones por tamaño molecular y uno por intercambio iónico. La presencia de Tc45 en las fracciones obtenidas fue monitoreada con sueros anti T. cruzi generados en dos cepas congénitas de ratones (A.SW/A.CA) y en conejos. Aunque en las tres cromatografías se lograron grados importantes de purificación, el intercambio iónico dio los mejores resultados, al entregar una fracción que presentó una sola banda en inmunoelectrotransferencia, monitoreada con un suero de conejo poliespecífico. La metodología descrita tiene potencial para ser escalada y generar cantidades adecuadas de Tc45 para ser usado en ensayos de protección activa, secuenciación y obtención de anticuerpos monoclonales
Subject(s)
Mice , Animals , Antigens , Chromatography , Immunogenetics/methods , Trypanosoma cruzi/geneticsSubject(s)
Humans , Male , Female , Infant , Child, Preschool , Hypothalamic Diseases/surgery , Hamartoma/surgery , Puberty, Precocious/etiologyABSTRACT
By using a specific, repetitive DNA probe, we have been able to detect picograms of P. berghei DNA. With this probe we have determined that: a) P. berghei, innoculated into Norway Brown rats, reaches its peak of proliferation in the liver 44 after infection; b) gamma interferon inhibits in a dose-dependent fashion the development of liver exoerythrocytic forms (EEF) in vivo and in vitro, and; c) endogenous gamma interferon inhibits the development of EEF in hostys immunized with irradiated sporozoites. Related with and derived from these findings, was have found that, in order to obtain an effective immunity against malaria in experimental animal models, effector mechanisms mediated by cells are required. This is substantiated by the following facts: a) immune hosts innoculated with monoclonal antibodies aginst gamma interferon reversed their immunity against a sporozoite challenge; b) This immunity was also reversed when the animals were depleted from their CD8 positive cytotoxic T cells. Therfore, sterile immunity against this parasite requires not only the presence of antibodies but also the inhibition of the EEF by gamma interferon with participation of CD8 positive T cells
Subject(s)
Rats , Animals , DNA Probes , DNA, Protozoan/analysis , Malaria/immunology , Plasmodium berghei/immunology , Antibodies, Monoclonal/analysis , Immunity, Cellular , Interferons/pharmacology , Plasmodium berghei/drug effectsABSTRACT
Entre 1982 y 1986 se evaluó la eficacia y tolerancia de Ceftriaxona (CFX) en 67 casos de infecciones sistémicas en niños; 49 meningitis, 10 ventriculitis y 8 septicemias neonatales, con dosis de 100 mg/kg/día cada 12 o 24 hrs. Se observó curación bacteriológica con erradicación precoz del agente causal en 62 pacientes (92,5 por ciento) con un 68,7 por ciento de curación clínica y 31,3 por ciento de mejoría. La terapia fracasó en 1 paciente con ventriculitis en que no se retiró la prótesis colonizada, en un recién nacido de pretérmino con septicemia y en 3 pacientes con meningitis: un caso de infección por S. pneumoniiae, una meningo-ventriculitis neonatal por enterobacter hafniae y una infección intrahospitalaria por K. pneumoniae multirresistente. La CIM 90 de CFX frente a H. influenzae, S. pneumoniae, Streptococcus grupo B fue <0,04 ug/mlñ y los títulos inhibitorios de LCR en casos de meningitis fluctuaron entre 1/8 y 1/1024. Ceftriaxona demostró excelente eficacia clínica y bacteriológica con buena tolerancia y ventajas prácticas al administrarse 1 ó 2 veces al día