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1.
Clin Oncol (R Coll Radiol) ; 35(10): 665-672, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37487914

RESUMEN

AIMS: In the pivotal RECOURSE trial, trifluridine/tipiracil improved survival outcomes in refractory metastatic colorectal cancer (mCRC), while demonstrating an acceptable toxicity profile. Routine clinical practice evidence is important to support the ongoing value of recently approved medicines. Our objective was to assess the utilisation patterns and real-world effectiveness of trifluridine/tipiracil in previously treated mCRC patients. MATERIALS AND METHODS: This was a retrospective observational study including consecutive patients who started trifluridine/tipiracil between 1 April 2018 and 30 September 2019 in the medical oncology departments of three major public hospitals in Portugal. The primary outcome measure was overall survival. Associations between overall survival and patient and tumour characteristics were assessed using multivariate Cox regression analyses. RESULTS: In total, 111 patients were included in the study, with a mean age of 64 years. From these, 45.9% received two prior lines of treatment, 47.8% had three or more previous lines of treatment and 83.6% had Eastern Cooperative Oncology Group (ECOG) performance status 0-1 at baseline. The median duration of trifluridine/tipiracil treatment was 3.7 cycles (95% confidence interval 3.4-4.1). Most patients (80.4%) remained on their planned dose throughout the trifluridine/tipiracil treatment period, fulfilling 100% relative dose intensity. The median overall survival in the total study cohort was 7.9 months (95% confidence interval 6.4-9.8) and the median progression-free survival was 3.4 months (95% confidence interval 3.2-3.9). The median overall survival was significantly higher in patients with a normal serum lactate dehydrogenase (LDH) level (median overall survival 11.2 months for [135, 205] IU/l LDH [95% confidence interval 8.2-NR] and 13.6 months for [205, 251] IU/l LDH [95% confidence interval 8.2-NR]) and in better fitted (ECOG = 0-1) patients (median overall survival 8.0 months; 95% confidence interval 6.7-10.0). The median time to worsening performance status was 6.2 months (95% confidence interval 5.0-8.0). Treatment discontinuation due to adverse events was low (3.1%). CONCLUSION: Our study confirms the effectiveness of trifluridine/tipiracil in real-life mCRC patients. Overall survival and progression-free survival outcomes are consistent with the efficacy profile reported in the earlier randomised RECOURSE clinical trial. Like other real-world studies, we found no additional safety concerns in the use of trifluridine/tipiracil.


Asunto(s)
Neoplasias del Colon , Neoplasias Colorrectales , Neoplasias del Recto , Humanos , Persona de Mediana Edad , Uracilo/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Trifluridina/uso terapéutico , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Recto/tratamiento farmacológico , Combinación de Medicamentos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico
2.
J Laryngol Otol ; 127(6): 536-41, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23651576

RESUMEN

INTRODUCTION: Cisplatin is an effective chemotherapeutic agent commonly used in the treatment of malignant tumours, but ototoxicity is a significant side effect. OBJECTIVES: To discuss the mechanisms of cisplatin ototoxicity and subsequent cell death, and to present the results of experimental studies. MATERIAL AND METHODS: We conducted a systematic search for data published in national and international journals and books, using the Medline, SciELO, Bireme, LILACS and PubMed databases. RESULTS: The nicotinamide adenine dinucleotide phosphate oxidase 3 isoform (also termed NOX3) seems to be the main source of reactive oxygen species in the cochlea. These reactive oxygen species react with other molecules and trigger processes such as lipid peroxidation of the plasma membrane and increases in expression of the transient vanilloid receptor potential 1 ion channel. CONCLUSION: Cisplatin ototoxicity proceeds via the formation of reactive oxygen species in cochlear tissue, with apoptotic cell death as a consequence.


Asunto(s)
Antineoplásicos/toxicidad , Cisplatino/toxicidad , Cóclea/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Cóclea/metabolismo , Enfermedades Cocleares/inducido químicamente , Humanos , Especies Reactivas de Oxígeno/metabolismo
3.
Transplant Proc ; 42(5): 1724-8, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20620510

RESUMEN

BACKGROUND: Abdominal hernias are a common disease among cirrhotic patients, because of malnutrition and persistently high intra-abdominal pressure due to ascites. When tense ascites is present, life-threatening complications are likely to occur. In such cases, the morbidity and mortality rates are high. OBJECTIVE: We describe 3 cirrhotic patients with rare complicated hernias that needed surgical repair. We discuss optimal timing for surgical approaches and the necessity of ascites control before surgery, as well as the technical details of the procedures. METHOD: Review of hospital charts of selected rare cases of herniae in cirrhotic patients. CONCLUSION: Elective surgical approaches can treat even uncommon hernias in cirrhotic patients with good results.


Asunto(s)
Hernia Abdominal/complicaciones , Hernia Abdominal/cirugía , Cirrosis Hepática/complicaciones , Procedimientos Quirúrgicos Electivos , Humanos
4.
Surg Endosc ; 23(11): 2615-9, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19296173

RESUMEN

BACKGROUND: Recent advances in laparoscopic techniques have resulted in growing indications for laparoscopic hepatectomy. However, this procedure has not been widely developed, and anatomic segmental liver resection is not currently performed due to difficulty controlling the segmental Glissonian pedicles laparoscopically. This study aimed to report a novel technique for laparoscopic anatomic resection of left liver segments using the intrahepatic Glissonian approach based on small incisions according to anatomic landmarks such as Arantius' and round ligaments. METHODS: Nine consecutive patients underwent laparoscopic liver resection using the intrahepatic Glissonian technique from April 2007 to June 2008. Five patients underwent laparoscopic bisegmentectomy 2-3, one laparoscopic left hemihepatectomy, two resections of segment 3, and one resection of segment 4. RESULTS: One patient required a blood transfusion. The mean operation time was 180 min (range, 120-300 min), and the median hospital stay was 3 days (range, 1-5 days). No patient had postoperative signs of liver failure or bile leakage. No postoperative mortality was observed. CONCLUSION: The main advantage of the intrahepatic Glissonian procedure over other techniques is the possibility of gaining a rapid and precise access to the left Glissonian sheaths facilitating left hemihepatectomy, bisegmentectomy 2-3, and individual resections of segments 2, 3, and 4. The authors believe that the intrahepatic Glissonian technique facilitates laparoscopic liver resection and may increase the development of segment-based laparoscopic liver resection.


Asunto(s)
Pérdida de Sangre Quirúrgica/prevención & control , Hepatectomía/métodos , Laparoscopía/métodos , Neoplasias Hepáticas/cirugía , Adulto , Diagnóstico por Imagen/métodos , Femenino , Estudios de Seguimiento , Hemostasis Quirúrgica/métodos , Humanos , Cuidados Intraoperatorios/métodos , Hígado/cirugía , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Muestreo , Resultado del Tratamiento
5.
Surg Endosc ; 22(1): 245, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17973162

RESUMEN

BACKGROUND: Liver resection is the definitive treatment for unilateral hepatolithiasis. Recently, laparoscopic major hepatectomias have become more common and are being performed in highly specialized centers. However, few laparoscopic liver resections for hepatolithiasis have been reported. Chen et al. reported two cases of laparoscopic left lobectomy for hepatolithiasis, but to our knowledge, right hepatectomy has never been reported to date. This video demonstrates technical aspects of a totally laparoscopic right hepatectomy in a patient with hepatolithiasis. METHODS: A 21-year-old woman with right-sided nonoriental primary intrahepatic stones was referred for surgical treatment. The operation followed four distinct phases: liver mobilization, dissection of the right portal vein and right hepatic artery, extrahepatic dissection of the right hepatic vein, and parenchymal transection with harmonic shears and linear staplers for division of segment 5 and 8 branches of the middle hepatic vein. No Pringles' maneuver was used. In contrast to liver resection for other indications, the right bile duct was enlarged and filled with stones. It was divided during parenchymal transection and left open. After removal of the surgical specimen, the biliary tree was flushed with saline until stone clearance, under radioscopic surveillance, was complete. The right hepatic duct then was closed with running suture. RESULTS: The operative time was 240 min, and the estimated blood loss was 120 ml, with no blood transfusion. The hospital stay was 5 days. At this writing, the patient is well and asymptomatic 7 months after the procedure. CONCLUSION: Laparoscopic liver resection is safe and feasible for patients with hepatolithiasis and should be considered for those suffering from intrahepatic stones. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00464-007-9666-1) contains supplementary material, which is available to authorized users.


Asunto(s)
Laparoscopía/métodos , Litiasis/cirugía , Hepatopatías/cirugía , Adulto , Femenino , Estudios de Seguimiento , Hepatectomía/métodos , Humanos , Litiasis/diagnóstico , Hepatopatías/diagnóstico , Resultado del Tratamiento
6.
Br Dent J ; 204(2): E4, 2008 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-18037821

RESUMEN

OBJECTIVE: To study the volatile sulphur compounds (VSC) halitometry profile in a population with chronic caseous tonsillitis (CCT) and halitosis and to evaluate the relationship between the presence of a tonsillolith and abnormal halitometry in this population. DESIGN: Clinical prospective non-randomised study. SUBJECTS AND METHODS: Forty-nine patients with halitosis and CCT, 17 male (35%) and 32 female (65%), were selected among patients referred for CO(2) laser cryptolysis. Anamnesis, physical examination and VSC halitometry were carried out. Halitometry values less than 150 ppb of VSC were considered normal. RESULTS: Patients were divided in two groups: Group A - normal halitometry (41 patients - 83.7%) and Group B - abnormal halitometry (8 patients - 16.3%). Halitometry results in Group B were 5.2 times (429%) higher than in Group A and the majority of the patients with abnormal halitometry presented with a tonsillolith at the moment of examination. A tonsillolith was present in 75% of the patients with abnormal halitometry and only 6% of patients with normal halitometry values. CONCLUSIONS: The presence of a tonsillolith represents a tenfold increased risk of abnormal VSC halitometry and can be considered as a predictable factor for abnormal halitometry in patients with CCT.


Asunto(s)
Cálculos/complicaciones , Halitosis/etiología , Tonsila Palatina , Tonsilitis/complicaciones , Adolescente , Adulto , Cálculos/radioterapia , Métodos Epidemiológicos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Compuestos de Azufre/análisis
7.
Int J Food Sci Nutr ; 51(5): 341-52, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11103299

RESUMEN

In this study, a single, improved methodology was used to extract, fractionate and purify the 11S (legumin-type or related to the alpha-conglutin from Lupinus albus L.), 7S (vicilin-type or related to the beta-conglutin from L. albus) and 2S (related to the gamma-conglutin from L. albus) families of proteins from eight legume species: L. albus, Glycine max (L.) Merr., Pisum sativum L., Vicia faba L., Cicer arietinum L., Phaseolus vulgaris L., Lens culinaris Med. and Arachis hypogaea L. The sedimentation coefficients obtained varied from 1.9 to 8.1 for the gamma-conglutin-related proteins, from 5.1 to 10.5 for the beta-conglutin-related proteins and from 12.0 to 14.9 for the alpha-conglutin-related globulins. The gamma-conglutin-related proteins is the most heterogeneous group. Antibodies produced against each type of gamma-conglutin polypeptide chain recognize the other polypeptide chain as well as other polypeptides in the corresponding globulins from all species examined. The 7S globulins are typically composed of a large number of polypeptides, covering a wide range of molecular masses (10 to 70 kD). The presence of disulphide bonds is apparently absent and the occurrence of glycopolypeptides is not widespread. Finally, the 11S globulins are characteristically formed by a limited number of polypeptides that may be divided into a lighter group (20-25 kD) and a heavier group (35-50 kD). The presence of disulphide bonds is apparently widespread but the occurrence of glycopolypeptides seems to be relatively rare. Both the 7S family and the 11S globulins studied by immunoblotting exhibit a low level of structural similarity.


Asunto(s)
Fabaceae/química , Globulinas/aislamiento & purificación , Proteínas de Plantas/aislamiento & purificación , Plantas Medicinales , Fraccionamiento Químico/métodos , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida/métodos , Fabaceae/clasificación , Globulinas/química , Immunoblotting , Proteínas de Plantas/química
8.
J Agric Food Chem ; 48(11): 5432-9, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11087497

RESUMEN

The proteins from Lathyrus sativus Linn. (chickling vetch or grass pea) seeds were investigated. Protein constitutes approximately 20% of the seed dry weight, >60% of which is composed by globulins and 30% by albumins. A single, 24 kDa polypeptide comprises more than half of the protein present in the albumin fraction. The globulins may be fractionated into three main components, which were named alpha-lathyrin (the major globulin), beta-lathyrin, and gamma-lathyrin. alpha-Lathyrin, with a sedimentation coefficient of approximately 18S, is composed of three main types of unglycosylated subunits (50-66 kDa), each of which produce, upon reduction, a heavy and a light polypeptide chain, by analogy with 11S. beta-Lathyrin, with a sedimentation coefficient of 13S, is composed by a relatively large number of subunits (8-66 kDa). Two major polypeptides are glycosylated and exhibit structural similarity with beta-conglutin from Lupinus albus. One of these possesses an internal disulfide bond. gamma-Lathyrin, with a sedimentation coefficient of approximately 5S, contains two interacting, unglycosylated polypeptides, with no disulfide bonds: the major 24 kDa albumin and the heavier (20 kDa) polypeptide chain of La. sativus lectin.


Asunto(s)
Fabaceae/química , Glucósidos/química , Proteínas de Plantas/química , Plantas Medicinales , Semillas/química , Secuencia de Aminoácidos , Centrifugación por Gradiente de Densidad , Electroforesis en Gel de Poliacrilamida , Glicosilación , Immunoblotting , Lectinas/química , Datos de Secuencia Molecular , Lectinas de Plantas , Proteínas de Plantas/aislamiento & purificación , Alineación de Secuencia , Homología de Secuencia de Aminoácido
9.
Electrophoresis ; 21(3): 641-4, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10726771

RESUMEN

Two-dimensional electrophoresis of proteins is often precluded due to the lack of solubilization of cell membrane extracts in an aqueous medium. Various additives and detergents have been used to circumvent the problem, but their efficacy may not be satisfactory. In this study, the removal of lipidic components of the cell membrane extract with chloroform-methanol was used to achieve solubilization. Optimal delipidation was obtained with acetone washings. This procedure increased solubilization of membrane proteins from a murine macrophage cell line, thus showing a substantial improvement in gel resolution. The two-dimensional gels loaded with delipidated extract proved to be free of smearing and horizontal streaking. In addition, other protein spots were revealed that were not detected in the gels loaded with undelipidated cell membrane extract.


Asunto(s)
Electroforesis en Gel Bidimensional/métodos , Lípidos/química , Macrófagos/química , Proteínas de la Membrana/química , Animales , Línea Celular , Ratones , Solubilidad
10.
Mem Inst Oswaldo Cruz ; 94 Suppl 1: 249-52, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10677727

RESUMEN

Integration of kDNA sequences within the genome of the host cell shown by PCR amplification with primers to the conserved Trypanosoma cruzi kDNA minicircle sequence was confirmed by Southern hybridization with specific probes. The cells containing the integrated kDNA sequences were then perpetuated as transfected macrophage subclonal lines. The kDNA transfected macrophages expressed membrane antigens that were recognized by antibodies in a panel of sera from ten patients with chronic Chagas disease. These antigens barely expressed in the membrane of uninfected, control macrophage clonal lines were recognized neither by factors in the control, non-chagasic subjects nor in the chagasic sera. This finding suggests the presence of an autoimmune antibody in the chagasic sera that recognizes auto-antigens in the membrane of T. cruzi kDNA transfected macrophage subclonal lines.


Asunto(s)
Autoinmunidad/genética , Enfermedad de Chagas/genética , ADN de Cinetoplasto/análisis , Transfección/genética , Trypanosoma cruzi/genética , Animales , Enfermedad de Chagas/sangre , Enfermedad de Chagas/inmunología , Genoma , Humanos , Macrófagos , Transfección/inmunología
11.
Mol Biochem Parasitol ; 91(2): 263-72, 1998 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-9566519

RESUMEN

A novel proteolytic activity was identified in epimastigote, amastigote and trypomastigote forms of Trypanosoma cruzi using the fluorogenic substrate N-Succinyl-Leu-Leu-Val-Tyr-7-amido-4-methylcoumarin. Epimastigotes showed enzyme activity to be 2-fold higher than amastigotes and trypomastigotes. The protease that displays this activity was purified from epimastigote forms by a four step chromatographic procedure: Diethylaminoethyl-Sephacel, Phenyl-Sepharose, Phenyl-Superose, and Concanavalin A Sepharose columns. The purified enzyme is a glycoprotein that migrates as a 30 kDa protein in 12.5% SDS-polyacrylamide gel electrophoresis (PAGE), under reducing conditions. Its optimal enzymatic activity on both fluorogenic and protein substrates was found to occur at an acidic pH. The inhibition pattern of the purified 30 kDa protease showed that it belongs to the cysteine-protease class. In addition to the synthetic substrate, the purified protease hydrolysed bovine serum albumin (BSA) and human type I collagen. The N-terminal amino acid sequence of the protease shows similarity to the mammalian cathepsin B protease.


Asunto(s)
Cisteína Endopeptidasas/metabolismo , Trypanosoma cruzi/enzimología , Secuencia de Aminoácidos , Animales , Cromatografía en Agarosa , Colágeno/metabolismo , Cisteína Endopeptidasas/química , Cisteína Endopeptidasas/aislamiento & purificación , Inhibidores de Cisteína Proteinasa/farmacología , Electroforesis en Gel de Poliacrilamida , Humanos , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Alineación de Secuencia , Albúmina Sérica Bovina/metabolismo , Especificidad por Sustrato , Trypanosoma cruzi/crecimiento & desarrollo
13.
Planta ; 203(1): 26-34, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9299789

RESUMEN

During germination of Lupinus albus seeds, a 20-kDa polypeptide accumulates in the cotyledons of 4-d-old plants (Ferreira et al., 1995b, J Exp Bot 46: 211-219). Immunological, polypeptide cleavage with cyanogen bromide and amino acid sequencing experiments indicate that the 20-k-Da polypeptide and ubiquitin are structurally unrelated. However, there is a strong sequence homology between the 20-kDa polypeptide and the vicilin-like storage proteins from pea and soybean. Our results indicate that the 20-kDa polypeptide is an intermediate breakdown products of beta-conglutin catabolism, the vicilin-like storage protein from L. albus, and that its interaction with anti-ubiquitin antibodies results from the recognition of the antibodies by the 20-kDa polypeptide rather than by the opposite. Besides rabbit anti-ubiquitin antibodies, the 20-kDa polypeptide interacts with a variety of glycoproteins, including immunoglobulin G from several animal species, peroxidase and alkaline phosphatase, suggesting that it possess a lectin-type activity. Its activity is resistant to sodium dodecyl sulfate or methanol treatments, boiling and autoclaving. Purification of the 20-kDa polypeptide and immunological studies with anti-20-kDa-polypeptide antibodies showed that the non-glycosylated polypeptide is part of a glycoprotein with an estimated molecular mass of 210 kDa, composed of several types of structurally related subunit with molecular masses ranging from 14 to 50 kDa. Purified native protein containing the 20-kDa polypeptide self-aggregates in a calcium-dependent manner as reported for some glycosylated lectins. The possible physiological function of the 20-kDa polypeptide is discussed.


Asunto(s)
Fabaceae/fisiología , Proteínas de Plantas/metabolismo , Plantas Medicinales , Secuencia de Aminoácidos , Animales , Anticuerpos , Cromatografía por Intercambio Iónico , Cotiledón/fisiología , Electroforesis en Gel de Poliacrilamida , Immunoblotting , Lectinas/aislamiento & purificación , Lectinas/metabolismo , Datos de Secuencia Molecular , Peso Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/aislamiento & purificación , Lectinas de Plantas , Proteínas de Plantas/química , Proteínas de Plantas/aislamiento & purificación , Conejos , Ratas , Proteínas de Almacenamiento de Semillas , Semillas/fisiología , Alineación de Secuencia , Homología de Secuencia de Aminoácido
14.
Rev. Soc. Bras. Med. Trop ; Rev. Soc. Bras. Med. Trop;30(3): 187-192, maio-jun. 1997. tab, graf
Artículo en Inglés | LILACS | ID: lil-464386

RESUMEN

In this study, we isolated Trypanosoma cruzi from chronic Chagas heart disease and from megaesophagus patients. The parasite stock hSLU239 (heart disease) yielded clones h1 and h2, whereas stock mSEU142 (megaesophagus) yielded clones m1, m2, m3 and m4. The parasite growth kinetics, doubling time and differentiation in axenic liquid medium showed broad behavioral diversity. It was shown that a particular pattern of behavior for a parental stock could not necessarily be assigned for subsequent clones. This study indicates that i) each Chagas disease patient is infected with several T. cruzi populations; ii) clonal lines derived from patient samples may have different biological characteristics from the original isolate; and that iii) additional behavioral and/or molecular markers are required for further characterization of Trypanosoma cruzi stocks and clones derived from Chagas disease patients in order to identify correlations with pathology.


Neste estudo, foram obtidos estoques de Trypanosoma cruzi de pacientes chagásicos com a doença cardíaca ou com megaesôfago. O estoque hSLU239 (doença cardíaca) forneceu os clones h1 e h2, enquanto o estoque mSLU142 (megaesôfago) forneceu os clones m1, m2, m3 e m4. A cinética de crescimento do parasito, tempo de duplicação e diferenciação em meio líquido axênico mostraram ampla diversidade comportamental. Observou-se que um padrão particular de comportamento de um estoque parental podia não ser necessariamente encontrado na linhagem subclonal subseqüente. Este estudo indica que i) cada paciente chagásico é infectado com várias subpopulações de T. cruzi; ii) linhagens clonais derivadas de cada estoque do parasito podem ter características biológicas diferentes do isolado original de paciente chagásico; e que iii) marcadores comportamentais e/ou moleculares adicionais são necessários para melhor caracterização de estoques de T. cruzi e seus clones derivados de pacientes com doença de Chagas, a fim de identificar as possíveis correlações com a patologia.


Asunto(s)
Animales , Humanos , Ratones , Acalasia del Esófago/parasitología , Conducta Animal , Cardiomiopatía Chagásica/parasitología , Enfermedad de Chagas/parasitología , Trypanosoma cruzi/aislamiento & purificación , Enfermedad Crónica , Parasitología/métodos , Factores de Tiempo , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/patogenicidad
15.
Biochem J ; 318 ( Pt 1): 227-34, 1996 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-8761476

RESUMEN

The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a +5 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35S-labelled ribulose bisphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose bisphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose bisphosphate carboxylase. For short periods of time (< 1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose bisphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photo-synthetic tissues.


Asunto(s)
Plantas/enzimología , Ribulosa-Bifosfato Carboxilasa/química , Ribulosa-Bifosfato Carboxilasa/efectos de la radiación , Rayos Ultravioleta , Cromatografía , Electroforesis en Gel de Poliacrilamida , Fructosadifosfatos/farmacología , Fructosafosfatos/farmacología , Immunoblotting , Cinética , Peso Molecular , Pentosafosfatos/farmacología , Péptidos/química , Péptidos/aislamiento & purificación , Conformación Proteica , Ribulosa-Bifosfato Carboxilasa/metabolismo , Alcoholes del Azúcar/farmacología
16.
Mutat Res ; 305(2): 189-96, 1994 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-7510030

RESUMEN

The carcinogenic activity of antitrypanosomal 2-nitroimidazole, 5-nitroimidazole and 5-nitrofuran derivatives was assessed in female Swiss mice of the same age group. A statistically significantly higher incidence of growths was seen in mice into which 2-nitro had been injected than in mice receiving 5-nitro derivatives intraperitoneally. A histologic type of lymphoblastic lymphoma that invades lymph nodes, spleen, liver, lungs and lymphatic tissue elsewhere was frequently found in nitroarene-treated mice. Further, it is shown that the potency of the drug, rather than the duration of its administration, was usually associated with the growth of lymphomas. The 2-nitro derivative which induced the highest incidence of lymphomas significantly decreased the survival of treated mice; this probably occurred because it undergoes enzymatic reduction of the nitro group more efficiently than the 5-nitro compounds used. The differences of incidence of lymphomas in mice receiving any of these nitroarenes and in control mice that received daily injections of 0.15 M saline were statistically significant (alpha = 0.05). The indiscriminate use of these nitroarenes to treat Trypanosoma cruzi infections in man could therefore induce a significant number of lymphomas.


Asunto(s)
Carcinógenos/toxicidad , Enfermedad de Chagas/tratamiento farmacológico , Linfoma/inducido químicamente , Tripanocidas/toxicidad , Animales , División Celular/efectos de los fármacos , Femenino , Hígado/efectos de los fármacos , Hígado/patología , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/patología , Linfoma/patología , Ratones , Estructura Molecular , Nifurtimox/uso terapéutico , Nifurtimox/toxicidad , Nitroimidazoles/uso terapéutico , Nitroimidazoles/toxicidad , Tripanocidas/uso terapéutico
17.
Am J Trop Med Hyg ; 43(2): 146-58, 1990 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-2117856

RESUMEN

Administration of the trypanocidal drug, Benznidazole (N-benzyl-2-nitro-imidazoleacetamide) to Trypanosoma cruzi-infected rabbits did not arrest the destructive Chagas' heart myocarditis. A typical feature of lymphocytic infiltrates associated with non-parasitized heart cell lysis was present in both treated and untreated groups of rabbits. Benznidazole-treated rabbits had their survival time shortened, probably as a consequence of Chagas' heart disease and of the development of lymphomas. The survival time of untreated T. cruzi-infected rabbits was 765 +/- 639 days and those treated with Benznidazole in the chronic phase of infection survived for 392 +/- 571 days. Malignant, non-Hodgkin's lymphomas were present in 38% of the rabbits that received the nitroarene therapy. Testicular atrophy was observed in 2 out of 10 nitroarene-treated rabbits. Benznidazole administration caused severe cell-mediated immunosuppression in T. cruzi-infected and BCG-immunized rabbits. Specific antibodies against the parasite and an unrelated antigen were detected in high levels, regardless of the nitroarene administration.


Asunto(s)
Cardiomiopatía Chagásica/prevención & control , Enfermedad de Chagas/tratamiento farmacológico , Linfoma no Hodgkin/inducido químicamente , Nitroimidazoles/efectos adversos , Tripanocidas/efectos adversos , Animales , Anticuerpos Antiprotozoarios/biosíntesis , Cardiomiopatía Chagásica/patología , Enfermedad de Chagas/patología , Femenino , Hipersensibilidad Tardía , Inmunidad Celular/efectos de los fármacos , Pruebas Intradérmicas , Hígado/patología , Linfoma no Hodgkin/patología , Masculino , Estructura Molecular , Miocardio/patología , Nitroimidazoles/uso terapéutico , Conejos , Tripanocidas/uso terapéutico , Trypanosoma cruzi/inmunología
18.
J Comp Pathol ; 103(1): 37-48, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2203830

RESUMEN

Use of 2-nitroimidazole, 5-nitrofuran and 5-nitroimidazole compounds in T. cruzi-infected rabbits resulted in a reduction in duration of parasitaemia in comparison with untreated, infected rabbits. The chronic myocarditis associated with Chagas' disease was not, however, prevented in nitroarene-treated rabbits; lymphocytic infiltrates associated with cardiac cell lysis, in the absence of parasites in situ, were present in both treated and untreated rabbits. The carcinogenic effect of each trypanocidal nitroarene used in this study was also assessed. Administration of nitroarenes to rabbits resulted in the appearance of solid tumours in 37.8 per cent of animals that received drug therapy. Untreated, control rabbits in this series did not show tumour growth. Furthermore, malignant, mixed-cell type, non-Hodgkin's lymphomas were seen in 32.4 per cent of the treated rabbits. It seems that a direct relationship could be present between the presence of the nitro group, the trypanocidal cytotoxicity and the prevalence of tumours. Benznidazole cleared up parasitaemias in the shortest time and was associated with 41.6 per cent of lymphoma growths, whereas MK-436 required twice as much time to clear blood parasites, and showed lymphomas in 25 per cent of experimental rabbits. The demonstration of a high prevalence of malignant tumours in addition to the chronic myocarditis of Chagas' disease in nitroarene-treated rabbits is important since indiscriminate use of such compounds currently used to treat T. cruzi infections in man could increase the risk of lymphoma.


Asunto(s)
Cardiomiopatía Chagásica/prevención & control , Linfoma no Hodgkin/inducido químicamente , Miocarditis/prevención & control , Nitrofuranos/efectos adversos , Nitroimidazoles/efectos adversos , Animales , Cardiomiopatía Chagásica/patología , Femenino , Inyecciones Intraperitoneales , Masculino , Miocarditis/patología , Miositis/etiología , Nifurtimox/efectos adversos , Nitrofuranos/administración & dosificación , Nitroimidazoles/administración & dosificación , Conejos , Trypanosoma cruzi/efectos de los fármacos
19.
Infect Immun ; 57(9): 2640-4, 1989 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2474498

RESUMEN

In this study, we assessed the proliferative response of T cells from mice chronically infected with Trypanosoma cruzi to actin, myosin, or T. cruzi soluble antigen (SA). We report here that CD4+ T cells from mice chronically infected with T. cruzi proliferated in response to myosin but not to actin, whereas cells from naive mice did not proliferate against any of the antigens tested. Antisera raised against myosin- or SA-activated T cells specifically inhibited respectively, the myosin or SA in vitro proliferative response, whereas the response to unrelated antigen remained unimpaired. Sera from chronically infected mice failed to show any significant inhibitory activity. The above findings suggest that autoreactive and T. cruzi-reactive T cells belong to different, perhaps nonoverlapping, compartments of the immune cell repertoire of mice chronically infected with T. cruzi. The failure of infected mice to trigger the suppressive mechanisms described here might be the primary immune defect leading to breakdown of self-tolerance and unopposed, perhaps tissue-damaging, autoimmunity in experimental Chagas' disease.


Asunto(s)
Antígenos de Diferenciación de Linfocitos T , Enfermedades Autoinmunes/inmunología , Enfermedad de Chagas/inmunología , Miosinas/inmunología , Linfocitos T/inmunología , Trypanosoma cruzi/inmunología , Adyuvantes Inmunológicos/inmunología , Animales , Antígenos de Protozoos/inmunología , Enfermedades Autoinmunes/sangre , Enfermedad de Chagas/sangre , Enfermedad Crónica , Epítopos/inmunología , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos CBA , Fenotipo , Factores Supresores Inmunológicos/sangre , Factores Supresores Inmunológicos/genética , Linfocitos T/clasificación
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