RESUMEN
Nonsteroid anti-inflammatory drug glucural (water-soluble N-methyl-D-glucosamine complex with 6-methyluracyl) improves survival of isolated rat hepatocytes stored in suspension. This effect of glucural is presumably explained by its membranotropism.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Citoprotección/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Hepatocitos/fisiología , Uracilo/análogos & derivados , Animales , Supervivencia Celular/efectos de los fármacos , Citoprotección/fisiología , Consumo de Oxígeno/efectos de los fármacos , Ratas , Uracilo/farmacologíaRESUMEN
INTRODUCTION: Anterior knee instability caused by anterior cruciate ligament (ACL) deficiency results in meniscal as well as chondral femorotibial and/or femoropatellar damages over a more or less long duration delay. This study's objectives were, in chronically deficient ACL patients, to assess onset delay for developing chondral patella lesions and also analyse these lesions characteristics in relation to laxity duration. HYPOTHESIS: Chondral patellar lesions in ACL deficient knees get worse with time. MATERIAL AND METHODS: We reviewed 250 charts of patients who had undergone arthroscopically assisted surgery for knee anterior laxity. The arthroscopic procedures were conducted between January 1995 and January 2005. Chondral damages were evaluated at surgery according both to International Cartilage Repair Society (ICRS) and Bauer and Jackson classifications. The data were analyzed using the Kruskal-Wallis test and the Fisher exact test. RESULTS: Of the 250 analysed charts, 72 patients (28.8%) were found to present chondral patella lesions. The majority of these lesions were superficial and involved the lateral facet area. We observed a statistically significant ICRS worsening grade in relation to laxity duration. DISCUSSION: Few publications in the literature report patellar involvement in anterior laxity of the knee. However, our results are comparable to those of the rare series found. The pathomechanics of these lesions has not yet been precisely identified and requires further biomechanical studies. CONCLUSION: Patellar damage is frequent with anterior laxity (28.8% in our series) and duration is correlated with statistically significant aggravation of these lesions. Currently, the assessment of these patellar lesions is considered less important than meniscal and femorotibial lesions, even though the natural history of ACL disruption seems to be evolving toward degeneration of all the compartments of the knee, including the femoropatellar compartment.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Enfermedades de los Cartílagos/patología , Inestabilidad de la Articulación/complicaciones , Rótula/patología , Adolescente , Adulto , Ligamento Cruzado Anterior/cirugía , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Rótula/lesiones , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Factores de Tiempo , Adulto JovenAsunto(s)
Antifúngicos/farmacocinética , Huesos/metabolismo , Pirimidinas/farmacocinética , Líquido Sinovial/metabolismo , Triazoles/farmacocinética , Anciano de 80 o más Años , Antifúngicos/farmacología , Artritis Infecciosa/tratamiento farmacológico , Artritis Infecciosa/microbiología , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Aspergillus fumigatus/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Pruebas de Sensibilidad Microbiana , Pirimidinas/farmacología , Triazoles/farmacología , VoriconazolRESUMEN
PURPOSE OF THE STUDY: This is a retrospective analysis of patients aged over 60 years treated in a single center for intra-articular fractures of the distal humerus. Outcomes were compared with published results for osteosynthesis and arthroplasty. MATERIAL AND METHODS: The cohort included 34 patients (36 fractures) reviewed at mean 35 months. Mean age was 77.6 years. Fracture types were: C1: 8, C2: 10, C3: 18. The transtricipital posteromedial approach was used in the majority of patients. Fixation was achieved with a prebent lateral plate (n=11 fractures), a Y-plate (n=9), two plates (n=4), pins or screws (n=9) and an external fixator (n=3). Outcome was assessed with the Mayo elbow score, the Bröberg radiographic score and patient satisfaction. The social impact was also noted. RESULTS: The mean Mayo elbow score was 73.3; outcome was excellent (n=13), good (n=8), fair (n=5) and poor (n=10). Pain persisted in 23 patients. The mean range of movement was 80 degrees . Patient satisfaction remained good. Ten patients did not recover their preoperative level of autonomy. Radiological signs of osteoarthritis were noted for 75% of patients and nonunion of the humeral fracture in 32%. There were three superficial infections and four neurological lesions. DISCUSSION: Good and very good outcome was noted for 59% of the osteosyntheses in this series, compared with 71% in the literature. The rate for arthroplasty is 95%. The mean range of motion is 101 degrees , 17% of patients with a prosthesis complain of pain, 5% develop a superficial infection and 6.5% suffer neurological injury. The estimated rate of revision for arthroplasty is 11% at 7 years. CONCLUSION: Beyond the age of 65 years and based on evidence reported in the literature, it would be advisable to prefer another mode of treatment for these intra-articular fractures, for example elbow arthroplasty, particularly for comminutive fractures on osteoporotic bone.
Asunto(s)
Fijación Interna de Fracturas/métodos , Fracturas del Húmero/cirugía , Factores de Edad , Anciano , Anciano de 80 o más Años , Artroplastia , Placas Óseas , Tornillos Óseos , Estudios de Cohortes , Articulación del Codo/diagnóstico por imagen , Articulación del Codo/fisiopatología , Femenino , Estudios de Seguimiento , Fijación Interna de Fracturas/instrumentación , Fracturas no Consolidadas/etiología , Humanos , Fracturas del Húmero/clasificación , Fracturas del Húmero/diagnóstico por imagen , Húmero/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Osteoartritis/diagnóstico por imagen , Satisfacción del Paciente , Radiografía , Rango del Movimiento Articular/fisiología , Reoperación , Estudios Retrospectivos , Ajuste Social , Infección de la Herida Quirúrgica/etiología , Resultado del TratamientoRESUMEN
Intraerythrocytic malaria parasites replicate by the process of schizogeny, during which time they copy their genetic material and package it into infective merozoites. These merozoites must then exit the host cell to invade new erythrocytes. To better characterize the events of merozoite escape, erythrocytes containing Plasmodium falciparum schizonts were cultured in the presence of the cysteine protease inhibitor, l-transepoxy-succinyl-leucylamido-(4-guanidino)butane (E64). This treatment resulted in the accumulation of extraerythrocytic merozoites locked within a thin, transparent membrane. Immunomicroscopy demonstrated that the single membrane surrounding the merozoites is not erythrocytic but rather is derived from the parasitophorous vacuolar membrane (PVM). Importantly, structures identical in appearance can be detected in untreated cultures at low frequency. Further studies revealed that (i) merozoites from the PVM-enclosed merozoite structures (PEMS) are invasive, viable, and capable of normal development; (ii) PEMS can be purified easily and efficiently; and (iii) when PEMS are added to uninfected red blood cells, released merozoites can establish a synchronous wave of infection. These observations suggest that l-transepoxy-succinyl-leucylamido-(4-guanidino)butane (E64) causes an accumulation of an intermediate normally present during the process of rupture. We propose a model for the process of rupture: merozoites enclosed within the PVM first exit from the host erythrocyte and then rapidly escape from the PVM by a proteolysis-dependent mechanism.
Asunto(s)
Endopeptidasas/metabolismo , Eritrocitos/parasitología , Leucina/análogos & derivados , Plasmodium falciparum/metabolismo , Animales , Supervivencia Celular/efectos de los fármacos , Membrana Eritrocítica/enzimología , Membrana Eritrocítica/metabolismo , Membrana Eritrocítica/parasitología , Membrana Eritrocítica/ultraestructura , Eritrocitos/enzimología , Eritrocitos/metabolismo , Eritrocitos/ultraestructura , Técnica del Anticuerpo Fluorescente Indirecta , Histocitoquímica , Humanos , Leucina/farmacología , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/ultraestructura , Microscopía Electrónica , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/enzimología , Plasmodium falciparum/ultraestructura , Inhibidores de Proteasas/farmacologíaRESUMEN
An encoded 13,020-member combinatorial library was synthesized containing a statine core. Evaluation of this library with plasmepsin II, an aspartyl protease required for hemoglobin metabolism in the malaria parasite, led to the identification of potent and selective inhibitors as well as novel structure-activity relationships.
Asunto(s)
Aminoácidos , Antimaláricos/síntesis química , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Bases de Datos como Asunto , Oligopéptidos/síntesis química , Plasmodium falciparum/enzimología , Inhibidores de Proteasas/síntesis química , Animales , Antimaláricos/química , Antimaláricos/farmacología , Clonación Molecular , Diseño de Fármacos , Hemoglobinas/metabolismo , Humanos , Estructura Molecular , Oligopéptidos/química , Oligopéptidos/metabolismo , Oligopéptidos/farmacología , Biblioteca de Péptidos , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Proteínas Protozoarias , Proteínas Recombinantes/antagonistas & inhibidores , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
The malaria organism Plasmodium falciparum detoxifies heme released during degradation of host erythrocyte hemoglobin by sequestering it within the parasite digestive vacuole as a polymer called hemozoin. Antimalarial agents such as chloroquine appear to work by interrupting the heme polymerization process, but their efficacy has been impaired by the emergence of drug-resistant organisms. We report here the identification of a new class of antimalarial compounds, hexadentate ethylenediamine-N, N'-bis[propyl(2-hydroxy-(R)-benzylimino)]metal(III) complexes [(R)-ENBPI-M(III)] and a corresponding ((R)-benzylamino)] analog [(R)-ENBPA-M(III)], a group of lipophilic monocationic leads amenable to metallopharmaceutical development. Racemic mixtures of Al(III), Fe(III), or Ga(III) but not In(III) (R)-ENBPI metallo-complexes killed intraerythrocytic malaria parasites in a stage-specific manner, the R = 4,6-dimethoxy-substituted ENBPI Fe(III) complex being most potent (IC50 approximately 1 microM). Inhibiting both chloroquine-sensitive and -resistant parasites, potency of these imino complexes correlated in a free metal-independent manner with their ability to inhibit heme polymerization in vitro. In contrast, the reduced (amino) 3-MeO-ENBPA Ga(III) complex (MR045) was found to be selectively toxic to chloroquine-resistant parasites in a verapamil-insensitive manner. In 21 independent recombinant progeny of a genetic cross, susceptibility to this agent mapped in perfect linkage with the chloroquine resistance phenotype suggesting that a locus for 3-MeO-ENBPA Ga(III) susceptibility was located on the same 36-kilobase segment of chromosome 7 as the chloroquine resistance determinant. These compounds may be useful as novel probes of chloroquine resistance mechanisms and for antimalarial drug development.
Asunto(s)
Antimaláricos/farmacología , Cloroquina/farmacología , Resistencia a Medicamentos , Plasmodium falciparum/efectos de los fármacos , Transportadoras de Casetes de Unión a ATP/antagonistas & inhibidores , Animales , Cationes , Compuestos Férricos/farmacología , Hemo/química , Hemoproteínas/química , Metales/química , Metales/farmacologíaRESUMEN
In Plasmodium falciparum, a cysteine protease known as falcipain has been implicated in the essential metabolic process of hemoglobin degradation. Parallel lines of investigation, using native or recombinant enzyme, have led to differing conclusions about the specificity and role of this protease. We have now determined that (1) Native falcipain does not cleave hemoglobin unless this substrate has first been denatured by reducing agents, acid-acetone treatment or plasmepsin action. (2) Reducing agents such as glutathione cannot denature hemoglobin in the presence of catalase, which is accumulated in the digestive vacuole. (3) The purified native enzyme has kinetics similar to those obtained with trophozoite extract, but substantially different from those of recombinant enzyme. (4) Although there are numerous cysteine protease genes in the P. falciparum genome, the falcipain gene is the only one whose transcript can be detected in the early intraerythrocytic parasites. We conclude that falcipain likely works by degrading hemoglobin fragments after initial aspartic protease attack has denatured the substrate. We propose that falcipain inhibitors block the initial steps of degradation indirectly by promoting vacuolar accumulation of osmotically active hemoglobin peptides.
Asunto(s)
Cisteína Endopeptidasas/metabolismo , Hemoglobinas/metabolismo , Plasmodium falciparum/enzimología , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Catalasa/metabolismo , Cisteína Endopeptidasas/química , Cisteína Endopeptidasas/aislamiento & purificación , Inhibidores de Cisteína Proteinasa/farmacología , ADN Protozoario/análisis , Hemoglobinas/química , Humanos , Cinética , Leucina/análogos & derivados , Leucina/farmacología , Datos de Secuencia Molecular , Peso Molecular , Desnaturalización Proteica , ARN Protozoario/análisis , Sustancias Reductoras/farmacología , Vacuolas/enzimologíaRESUMEN
Plasmodium falciparum is the major causative agent of malaria, a disease of worldwide importance. Resistance to current drugs such as chloroquine and mefloquine is spreading at an alarming rate, and our antimalarial armamentarium is almost depleted. The malarial parasite encodes two homologous aspartic proteases, plasmepsins I and II, which are essential components of its hemoglobin-degradation pathway and are novel targets for antimalarial drug development. We have determined the crystal structure of recombinant plasmepsin II complexed with pepstatin A. This represents the first reported crystal structure of a protein from P. falciparum. The crystals contain molecules in two different conformations, revealing a remarkable degree of interdomain flexibility of the enzyme. The structure was used to design a series of selective low molecular weight compounds that inhibit both plasmepsin II and the growth of P. falciparum in culture.
Asunto(s)
Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/química , Hemoglobinas/metabolismo , Plasmodium falciparum/enzimología , Inhibidores de Proteasas/farmacología , Estructura Secundaria de Proteína , Secuencia de Aminoácidos , Animales , Catepsina D/química , Clonación Molecular , Secuencia Conservada , Cristalografía por Rayos X , Escherichia coli , Humanos , Conformación Molecular , Datos de Secuencia Molecular , Inhibidores de Proteasas/química , Proteínas Protozoarias , Proteínas Recombinantes/antagonistas & inhibidores , Proteínas Recombinantes/química , Homología de Secuencia de Aminoácido , Especificidad por SustratoRESUMEN
The human malaria parasite, Plasmodium falciparum, degrades nearly all its host cell hemoglobin during a short segment of its intraerythrocytic development. This massive catabolic process occurs in an acidic organelle, the digestive vacuole. Aspartic and cysteine proteases have been implicated in this pathway. We have isolated three vacuolar proteases that account for most of the globin-degrading activity of the digestive vacuole. One is the previously described aspartic hemoglobinase that initiates hemoglobin degradation. A second aspartic protease is capable of cleaving hemoglobin with an overlapping specificity, but seems to prefer acid-denatured globin. The third is a cysteine protease that does not recognize native hemoglobin but readily cleaves denatured globin. It is synergistic with the aspartic hemoglobinase, both by in vitro assay of hemoglobin degradation, and by isobologram analysis of protease inhibitor-treated parasites in culture. The cysteine protease is highly sensitive to chloroquine-heme complex, suggesting a possible mechanism of 4-aminoquinoline antimalarial action. The data suggest an ordered pathway of hemoglobin catabolism that presents an excellent target for chemotherapy.
Asunto(s)
Endopeptidasas/aislamiento & purificación , Hemoglobinas/metabolismo , Plasmodium falciparum/metabolismo , Secuencia de Aminoácidos , Animales , Cisteína Endopeptidasas/aislamiento & purificación , Endopeptidasas/fisiología , Datos de Secuencia Molecular , Vacuolas/enzimologíaRESUMEN
Intraerythrocytic malaria parasites rapidly degrade virtually all of the host cell hemoglobin. We have cloned the gene for an aspartic hemoglobinase that initiates the hemoglobin degradation pathway in Plasmodium falciparum. It encodes a protein with 35% homology to human renin and cathepsin D, but has an unusually long pro-piece that includes a putative membrane spanning anchor. Immunolocalization studies place the enzyme in the digestive vacuole and throughout the hemoglobin ingestion pathway, suggesting an unusual protein targeting route. A peptidomimetic inhibitor selectively blocks the aspartic hemoglobinase, prevents hemoglobin degradation and kills the organism. We conclude that Plasmodium hemoglobin catabolism is a prime target for antimalarial chemotherapy and have identified a lead compound towards this goal.
Asunto(s)
Ácido Aspártico Endopeptidasas/genética , Plasmodium falciparum/enzimología , Proteínas Protozoarias/genética , Secuencia de Aminoácidos , Animales , Antimaláricos/farmacología , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/metabolismo , Secuencia de Bases , Clonación Molecular , ADN Protozoario , Dipéptidos/farmacología , Exones , Hemoglobinas/metabolismo , Humanos , Microscopía Inmunoelectrónica , Datos de Secuencia Molecular , Plasmodium falciparum/efectos de los fármacos , Proteínas Protozoarias/antagonistas & inhibidores , Proteínas Protozoarias/metabolismo , Homología de Secuencia de Aminoácido , Vacuolas/enzimologíaRESUMEN
PCF1-1 is a dominant suppressor of a tRNA gene A block promoter mutation (A19) in Saccharomyces cerevisiae. Transcriptional activation by PCF1-1 was examined in vitro using whole-cell extracts and purified factors derived from mutant and wild-type strains. These experiments show that PCF1 is a general activator of RNA polymerase III (pol III) gene transcription. The transcription of all pol III genes analyzed to date, including type I and numerous type II genes, is increased 3-7 fold in mutant cell extracts. Single round transcription assays indicate that the PCF1-1 mutation increases the number of functional preinitiation complexes and suggest that this is achieved by increasing the intrinsic activity of the encoded product rather than its amount. Point mutations throughout the A block of the sup3-e gene and numerous B block mutations fail to abolish transcriptional activation suggesting that interactions between TFIIIC and the internal promoter are unaffected by PCF1-1. Moreover, TFIIIC purified from the mutant strain is incapable of conferring PCF1-1 transcriptional activity to a reaction in which the remaining components are wild-type. In contrast, the activity of the TFIIIB fraction is increased in PCF1-1 extracts and can reconstitute mutant levels of transcription when added to wild-type TFIIIC and polymerase. We conclude that PCF1 is a component or regulator of TFIIIB.
Asunto(s)
Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica/genética , Genes Fúngicos/genética , Saccharomyces cerevisiae/genética , Factores de Transcripción TFIII , Factores de Transcripción/genética , Secuencia de Bases , Proteínas Fúngicas/metabolismo , Genes Supresores/genética , Datos de Secuencia Molecular , Mutación/genética , Regiones Promotoras Genéticas/genética , ARN Polimerasa III/genética , ARN de Transferencia/genética , Factor de Transcripción TFIIIB , Factores de Transcripción/metabolismo , Transcripción Genética/genéticaRESUMEN
The fractional composition of chromatin proteins and an electron-microscopic pattern of cell ultrastructure of the Ehrlich ascite tumours and ascite lymphoma NK/Ly were studied when suppressing their growth by a combined action of cyclophosphane and polyene antibiotic. Changes in the fractional composition of chromatin proteins were found under the effect of levorin. A sharp increase in this effect and summation of heterogeneous morphological changes provoked by each of the preparation occur under a combined application of the preparations.
Asunto(s)
Antifúngicos/administración & dosificación , Candicidina/administración & dosificación , Carcinoma de Ehrlich/metabolismo , Ciclofosfamida/administración & dosificación , Linfoma/metabolismo , Animales , Candicidina/farmacología , Carcinoma de Ehrlich/tratamiento farmacológico , Carcinoma de Ehrlich/ultraestructura , Cromatina/metabolismo , Ciclofosfamida/farmacología , Quimioterapia Combinada , Femenino , Histonas/metabolismo , Linfoma/tratamiento farmacológico , Linfoma/ultraestructura , Masculino , Ratones , Proteínas de Neoplasias/metabolismoAsunto(s)
Quistes/cirugía , Timo/cirugía , Preescolar , Humanos , Enfermedades Linfáticas/cirugía , Masculino , Cuello/cirugíaRESUMEN
Study of an experimental neoplastic process induced by virus type strains of Rous's sarcoma has shown that amphotericin B potentiates antineoplastic action of cyclophosphamide. Administration of cytostatin does not affect the fractional composition of chromatin proteins. Administration of polyene changes this indicator, the changes being greater after combined use of both drugs. The character of a considerable part of the abnormalities in the fractional composition of chromatin proteins indicates that chromatin had been exposed to proteolytic enzymes.
Asunto(s)
Anfotericina B/farmacología , Virus del Sarcoma Aviar/efectos de los fármacos , Ciclofosfamida/administración & dosificación , Nucleoproteínas/metabolismo , Sarcoma Aviar/metabolismo , Anfotericina B/administración & dosificación , Animales , Transformación Celular Neoplásica/efectos de los fármacos , Embrión de Pollo , Pollos , Interacciones Farmacológicas , Electroforesis en Gel de Poliacrilamida , Sarcoma Aviar/tratamiento farmacológicoRESUMEN
The fractional composition of the proteins of the plasmatic membranes of the Ehrlich's tumor cells treated with various drugs was studied with the use of electrophoresis in polyacrylamide gel. It was shown that the character of the changes in the fractional composition of the plasmatic membrane proteins under the effect of levorin and cyclophosphamide was different. When the drugs were used in combination, summation of the changes induced by every drug alone was observed. Possible causes of the changes in the fractional composition of the membrane proteins are discussed.
Asunto(s)
Antifúngicos/uso terapéutico , Candicidina/uso terapéutico , Carcinoma de Ehrlich/análisis , Ciclofosfamida/uso terapéutico , Proteínas de la Membrana/análisis , Proteínas de Neoplasias/análisis , Animales , Carcinoma de Ehrlich/tratamiento farmacológico , Evaluación Preclínica de Medicamentos , Sinergismo Farmacológico , Quimioterapia Combinada , RatonesRESUMEN
The effect of oral levorin used for a prolonged period of time on the lipid composition and activity of alkaline phosphatase and invertase of the microvilli membranes of the small intestinal enterocytes of old dogs was studied. Higher ratios of cholesterol/phospholipids in the membranes and inactivation of alkaline phosphatase and invertase were noted in the old dogs as compared to the young ones. Exposure of the old dogs to levorin had a significant effect on the microvilli membranes of the intestinal epithelial cells. It was evident from a lower ratio of cholesterol/phospholipids in the membranes and stimulation of the alkaline phosphatase activity. It is supposed that the changes in the state of the microvilli membranes of the small intestinal mucosa due to levorin play a definite role in the mechanism of its hypercholesterolemic action.