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1.
Biochim Biophys Acta ; 1546(1): 171-84, 2001 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-11257520

RESUMEN

A potential therapy for antibiotic-associated pseudomembranous colitis is to bind Clostridium difficile toxins A and B using cholestyramine, a hydrophobic anion exchange medium. Frontal analysis in isotonic phosphate buffer was studied using post-column derivatization with o-phthalaldehyde, which gave a highly sensitive (> or =30 ng) flow-through analysis. Following load (1.5-3.0 microg toxin/3.6 mg), toxin A was bound at a slightly higher capacity than B, due to slower kinetics. A salt gradient eluted roughly 20% of bound toxin A with 0.6 M NaCl and toxin B with 1.1 M NaCl, hence toxin A showed weaker electrostatic affinity. The remainder of toxin A (65%) and some of toxin B (10% out of 50%) were eluted using a subsequent gradient to 60% acetonitrile in normal saline, which measured predominantly hydrophobic binding. Low and high affinity populations of both toxins were observed. Glycocholic acid or amino acids were competitive binders, although these components had little effect on the toxin A population bound primarily through ionic interactions. Competitive protein constituents in hamster cecal contents were also profiled. These results help to explain the variable clinical response in using cholestyramine to treat colitis. Using quaternary amine-polyhydroxymethacrylate (PHM) ion exchange chromatography, a trend for increased binding at higher pH was observed, especially for toxin A. Binding to strong cation exchange resins (sulfonate-PHM) was not observed. A range of reversed phase media retained both toxins, although recovery was very poor relative to protein standards. Size exclusion chromatography with light scattering detection showed that toxin B exists in different aggregation states, while toxin A remains monomeric.


Asunto(s)
Resinas de Intercambio Aniónico/química , Proteínas Bacterianas , Toxinas Bacterianas/química , Resina de Colestiramina/química , Clostridioides difficile/química , Enterotoxinas/química , Animales , Resinas de Intercambio Aniónico/uso terapéutico , Antibacterianos/uso terapéutico , Unión Competitiva , Tampones (Química) , Resina de Colestiramina/uso terapéutico , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Cromatografía por Intercambio Iónico , Cromatografía Liquida/métodos , Cricetinae , Quimioterapia Combinada , Enterocolitis Seudomembranosa/tratamiento farmacológico , Contenido Digestivo/química , Humanos , Cinética , Rayos Láser
2.
Biochim Biophys Acta ; 1472(3): 509-18, 1999 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-10564765

RESUMEN

Determination of amino acids in polymers with varying structure and charge was performed using vapor phase acid hydrolysis and subsequent precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Percent load of neutral, cationic and anionic peptide-modified synthetic polymers was accurately determined using this technique. Assay utility was shown for glycosaminoglycans and other sulfated polymers, neutral carbohydrate polymers such as agar, agarose, and cellulose, and polymers such as lipopolysaccharide and deoxyribonucleic acid. The carboxylated and sulfated molecules included chondroitin sulfate, hyaluronic acid, dermatan sulfate, and heparin, and the sulfated polymers included fucoidan, carrageenan, and dextran sulfate, as examples. Assayed cumulative amino acid concentrations (i.e. protein levels) are reported, although amino acid distribution data was also available from the analysis. Recovery was acceptable for the various compounds tested and did not correlate with structure. However, different sample sizes were necessary to achieve acceptable recovery, depending on the level of protein present in the matrix. While some matrices contained peaks in addition to the amino acids and amino sugars, they were not found to interfere using the standard gradient separation. Assayed amino acid profiles were compared for agaroses with differing electroendosmosis values and for agar samples from different parts of the globe. While the amounts of protein varied depending on source, the relative distribution of amino acids was very similar across the agar samples surveyed.


Asunto(s)
Aminoácidos/análisis , Cromatografía Líquida de Alta Presión/métodos , Polímeros/química , Proteínas/química , Agar/química , Aminoquinolinas , Carbamatos , Dicroismo Circular , Geles/química , Péptidos/química , Proteínas/análisis , Sefarosa/química
3.
Free Radic Biol Med ; 18(4): 709-20, 1995 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7750795

RESUMEN

The potential role of phospholipid metabolism in restricting lymphocyte proliferation under conditions of oxidative stress was investigated using [1-14C]-arachidonic acid (14C-AA) and 32P-orthophosphoric acid. Human peripheral blood lymphocytes (PBL) and PBL depleted of glutathione with L-buthionine-S,R-sulfoximine (BSO-PBL) were compared. The relative uniformity of glutathione depletion in the PBL population was assessed by flow cytometry. BSO-PBL were 40 to 90% depleted of glutathione 1 to 3 days after activation, respectively, and the BSO-PBL had unimpaired early activation events based on 32P-phosphatidylinositol levels. However, unlike stimulated PBL, which showed a progressive decrease in radioactivity incorporated into phosphatidylcholine and a corresponding increase into phosphatidylethanolamine, no significant differences occurred with BSO-PBL. Prelabeled BSO-PBL showed considerably more 14C radioactivity in the supernatant following 72-120 h stimulation with anti-CD3 than control PBL, which was mostly in the form of unmetabolized 14C-AA. Higher levels of leukotriene B4, 5-hydroxyeicosatetraenoate and 12-hydroxy-5,8,10-heptadecatrienoate also were observed with L-buthionine-S,R-sulfoximine treatment, which could explain the impaired proliferation obtained with a depletion of cellular glutathione. Both lysophosphatidylcholine and liberated free 14C-AA increased with L-buthionine-S,R-sulfoximine treatment following 72 h stimulation, suggesting functional impairment in the reacylating enzymes. The increased release of 14C-AA by BSO-PBL also may contribute to the imparied proliferation that occurs with loss of glutathione.


Asunto(s)
Glutatión/biosíntesis , Linfocitos/metabolismo , Fosfolípidos/metabolismo , Radioisótopos de Carbono , Recuento de Células , Cromatografía Líquida de Alta Presión , Citometría de Flujo , Radicales Libres , Humanos , Metionina/análogos & derivados , Estrés Oxidativo , Factores de Tiempo
4.
FEBS Lett ; 215(1): 58-62, 1987 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-3552735

RESUMEN

Comparative quantitative analysis of phylloquinone content and photochemically competent P-700 has been performed on photosystem I particles subjected to photolysis with ultraviolet irradiation. Nonirradiated control particles exhibit a phylloquinone/P-700 stoichiometry of 1.9 +/- 0.2. Photolysis of the photosystem I particles induces a progressive depletion of phylloquinone, however, photochemistry as assayed at room temperature by the photooxidation of P-700 is unaffected. These data are not consistent with the assignment of phylloquinone as a functional intermediate at room temperature between P-700 and the iron-sulfur clusters, center A and center B.


Asunto(s)
Clorofila/metabolismo , Transporte de Electrón , Proteínas de Plantas/metabolismo , Vitamina K 1/fisiología , Clorofila/efectos de la radiación , Complejos de Proteína Captadores de Luz , Fotólisis , Proteínas del Complejo del Centro de Reacción Fotosintética , Complejo de Proteína del Fotosistema I , Proteínas de Plantas/efectos de la radiación , Temperatura
5.
Invest Radiol ; 20(6): 632-7, 1985 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2933362

RESUMEN

Pharmacokinetics and excretion of iohexol, a new nonionic water-soluble contrast medium, were determined after lumbar myelography. Peak plasma concentrations were obtained 2 to 6 hours after injection and ranged from 29 to 177 microgram/ml. Terminal elimination half-life was 4.0 hours, and over 90% of the dose was recovered in the urine within 24 hours. In one patient with a large lumbar cauda equina tumor, absorption and excretion were delayed; but eventually 99% was recovered indicating a large capacity for reabsorption via the lumbar subarachnoid space. One mild headache of 5 minutes' duration was reported in a 73-year-old woman. No significant changes in vital signs, neurologic examinations, or serum chemistries were observed.


Asunto(s)
Medios de Contraste/metabolismo , Yodobenzoatos/metabolismo , Vértebras Lumbares/diagnóstico por imagen , Ácidos Triyodobenzoicos/metabolismo , Adulto , Anciano , Dolor de Espalda/diagnóstico por imagen , Cauda Equina/metabolismo , Femenino , Semivida , Humanos , Desplazamiento del Disco Intervertebral/metabolismo , Yohexol , Cinética , Masculino , Persona de Mediana Edad , Mielografía , Neurilemoma/metabolismo , Neoplasias del Sistema Nervioso Periférico/metabolismo , Estenosis Espinal/metabolismo , Tomografía Computarizada por Rayos X
6.
J Biochem Toxicol ; 10(3): 137-42, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7473604

RESUMEN

Similar to HIV-1-induced suppression of thymus-derived lymphocytes (T cells), oxidatively stressed T cells show inhibited DNA synthesis and proliferation. The influence of oxidative stress on nucleotide pools was explored using 3H-uridine addition to OKT3-stimulated peripheral blood lymphocytes. The cells were preincubated and stimulated in the presence of 1 mM buthionine sulfoximine to inhibit GSH synthesis. This treatment gave rise to a significant reduction in dUDP and TTP biosynthesis following 18-32 hours stimulation, indicating possible impairment of ribonucleotide reductase activity.


Asunto(s)
Linfocitos/metabolismo , Nucleótidos/sangre , Estrés Oxidativo/fisiología , Butionina Sulfoximina , Ciclo Celular , Células Cultivadas , Cromatografía Líquida de Alta Presión , Nucleótidos de Desoxiuracil/sangre , Inhibidores Enzimáticos/farmacología , Glutatión/sangre , Humanos , Activación de Linfocitos , Linfocitos/inmunología , Metionina Sulfoximina/análogos & derivados , Metionina Sulfoximina/farmacología , Muromonab-CD3/inmunología , Nucleótidos de Timina/sangre , Uridina/sangre
7.
Anal Biochem ; 244(2): 393-403, 1997 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-9025957

RESUMEN

Low-level (subanomole) determination of amino acids in samples of naturally derived polymeric carbohydrates has been demonstrated using vapor-phase acid hydrolysis and subsequent precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Application has been demonstrated for neutral polysaccharide polymers such as laminarin (beta-1,3; branched), curdland (beta-1,3; unbranched), pullulan (alpha-1, 6-maltotriose), glycogen (alpha-1,4-glucan), and inulin (polyfructose). Successful determination (acceptable recovery and lack of interferences) was possible in samples which also contained up to roughly 50 micrograms amino sugars (e.g., chitosan or glucans with copurified glucosamine oligomers), although optimum utility is for samples containing up to ca. 10 micrograms total amines. The limit of quantification was roughly 20 ng protein/ mg sample, based on analysis of reagent blanks, although the limit of detection was much lower (ca. 0.1 ng protein/mg sample). Incorporation of a relatively rapid hydrolysis (150 degrees C for 1.5 h) gave similar results to use of 110 degrees C for 24 h and allowed for relatively rapid processing. The method has shown good sensitivity, linearity, ruggedness, and ease. Recovery has been optimized, although yield varied somewhat depending on polymer composition.


Asunto(s)
Aminoácidos/análisis , Carbohidratos/química , Glucosamina/análisis , Polímeros/química , beta-Glucanos , Aminoquinolinas , Carbamatos , Cromatografía Líquida de Alta Presión/métodos , Glucanos/química , Inulina/química , Laminaria , Polisacáridos/química
8.
Prostaglandins ; 43(4): 339-49, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1609120

RESUMEN

We characterized the release of arachidonic acid (AA) metabolites in lung effluent following lung ischemia-reperfusion since they may contribute to the pathophysiology of reperfusion lung injury. The left pulmonary artery of rabbits (N = 5) was occluded for 24 hrs with a surgically implanted vascular clip. At 24 hrs, the heart and lungs were removed en bloc and perfused with Ringers-albumin (0.5 gm%) at 60 ml/min while statically inflated with 95% O2-5% CO2. The lipid fraction of the lung effluent was concentrated using the Bligh-Dyer extraction and analyzed by gradient RP-HPLC. Samples obtained in the first minute of reperfusion showed significant increases in LTB4 (+180%), LTC4 (+3600%), 15-HETE (+370%), 5-HPETE (+270%), PGE2 (+140%), 6-keto-PGF1 alpha (+110%) and 12-HHT (+160%) compared to the effluent from the right control lung. The reperfusion-induced increases in LTB4, LTC4, LTD4 and 15-HETE were inhibited greater than or equal to 70% by pretreatment with the 5-LO inhibitors L663,536 or L651,392. The increases in lipid concentrations corresponded to significantly increased pulmonary arterial pressure from a baseline value of 9.5 +/- 0.3 to 29.3 +/- 2.9 (cmH2O) during the first min of reperfusion. The pulmonary arterial pressure remained elevated for at least 20 min of reperfusion. Reperfusion also resulted in PMN uptake (assessed by lung tissue myeloperoxidase content) in the reperfused lung versus control lung (25.0 +/- 2.4 vs. 10.5 +/- 2.5 units). The generation of lipoxygenase metabolites during the initial phase of reperfusion may contribute to post-reperfusion PMN uptake and pulmonary vasoconstriction.


Asunto(s)
Araquidonato 5-Lipooxigenasa/metabolismo , Pulmón/metabolismo , Daño por Reperfusión/metabolismo , Animales , Arteriopatías Oclusivas/metabolismo , Cromatografía Líquida de Alta Presión , Femenino , Hemodinámica/fisiología , Técnicas In Vitro , Pulmón/irrigación sanguínea , Masculino , Neutrófilos/metabolismo , Arteria Pulmonar , Conejos
9.
Am Rev Respir Dis ; 147(1): 143-7, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8380539

RESUMEN

Cytokines may function as mediators of reperfusion tissue injury in lungs. Because the lung contains resident macrophages that can serve as potential sources of cytokines, we examined the possibility that pulmonary artery occlusion by reperfusion is a factor in mediating the release of cytokines. After left lung ischemia induced by a 24-h period of left pulmonary artery occlusion, we observed a transient increase in TNF-alpha concentration in lung effluent in rabbits during the period reperfusion. The peak TNF-alpha levels ranged from 55 to 335 pg/ml, and a mean peak time was at 45 to 60 min after the initiation of reperfusion. The TNF-alpha concentrations then decreased towards baseline. TNF-alpha was detected in control plasma or in plasma from sham-operated animals. Less than 10 pg/ml of endotoxin was detected in any samples. Lung tissue myeloperoxidase content, a measure of neutrophil infiltration, increased progressively during the 2-h reperfusion period. The time course of generation of TNF-alpha preceded the maximal rise in lung tissue myeloperoxidase activity. The data show that lung ischemia/reperfusion results in transient generation of TNF-alpha, which is known to mediate neutrophil sequestration. Neutrophil sequestration and resulting lung injury after reperfusion may be dependent on generation of TNF-alpha at the onset of reperfusion.


Asunto(s)
Pulmón/metabolismo , Arteria Pulmonar/fisiología , Daño por Reperfusión/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Constricción , Endotoxinas/análisis , Femenino , Prueba de Limulus , Pulmón/irrigación sanguínea , Masculino , Peroxidasa/metabolismo , Conejos
10.
Am J Physiol ; 264(4 Pt 2): H1161-5, 1993 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8476094

RESUMEN

We examined whether the generation of tumor necrosis factor (TNF-alpha) after lipopolysaccharide (LPS) challenge contributes to increases in lung vascular permeability and water content. Guinea pig lungs perfused at constant flow with Ringer-albumin solution (0.5 g/100 ml) were challenged for 120 min with LPS (Escherichia coli; final concentration 33 ng/ml; n = 5). Lung effluent samples were assayed for TNF-alpha activity using the modified L-929 fibroblast cytolytic assay. TNF-alpha concentrations increased in a time-dependent manner with a peak value of 100 +/- 20 pg/ml noted 90-120 min after LPS. Human neutrophils [polymorphonuclear leukocytes (PMN; 2 x 10(7)] added to the perfusion solution after endotoxin challenge (n = 5) produced a threefold increase in lung tissue myeloperoxidase (MPO) activity over control values. PMN, added after LPS and activated using phorbol 12-myristate 13-acetate (PMA; 5 x 10(-9) M; n = 6), produced three- to sixfold increases in mean pulmonary arterial pressure (Ppa) and pulmonary capillary pressure (Pcap), wet weight-to-dry weight ratio (W/D), and the pulmonary capillary filtration coefficient (Kf,c) over control values (P < 0.05). Activation of PMN with PMA in non-LPS-challenged lungs produced only threefold increases in Ppa and Pcap and did not change W/D and Kf,c. Infusion of an anti-TNF-alpha antibody before the LPS challenge reduced by approximately 50% the increases in Ppa, Pcap, MPO content, Kf,c, and lung wet weight gain (P < 0.05). Therefore, endotoxin-induced TNF-alpha generation in lungs significantly contributes to pulmonary sequestration of PMN. Activation of the sequestered PMN increases pulmonary vascular permeability and tissue water content.


Asunto(s)
Endotoxinas/sangre , Endotoxinas/fisiología , Neutrófilos/fisiología , Edema Pulmonar/etiología , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Animales , Relación Dosis-Respuesta a Droga , Escherichia coli , Cobayas , Lipopolisacáridos/farmacología , Pulmón/metabolismo , Pulmón/patología , Edema Pulmonar/metabolismo , Edema Pulmonar/fisiopatología , Presión Esfenoidal Pulmonar/fisiología , Acetato de Tetradecanoilforbol/farmacología , Factores de Tiempo
11.
Circ Res ; 68(4): 930-9, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1672631

RESUMEN

We previously have described the ability of alpha-thrombin (the native procoagulant enzyme) to stimulate adherence of neutrophils to pulmonary artery endothelial cells. In the present study, we observed that conditioned medium factors released by alpha-thrombin (10(-8) M) treatment of cultured ovine pulmonary artery endothelial cells increased neutrophil adherence to naive pulmonary artery endothelial monolayers. This effect was independent of any residual alpha-thrombin present in the medium. In contrast to thrombin-induced neutrophil adherence, adherence of neutrophils mediated by the conditioned medium was not inhibited by the anti-CD18 monoclonal antibody 60.3, indicating a CD18-independent mechanism. The factors generated by the action of alpha-thrombin on endothelial cells also resulted in concentration-dependent neutrophil migration. The neutrophil adherence- and migration-promoting activities were isolated in the ether portion after extraction of the conditioned medium. Chromatographic analysis showed that the active components (which resolved into two peaks by reversed-phase high-performance liquid chromatography) were relatively hydrophilic low molecular weight lipids without phosphorus or amino acids. Reconstitution of these peaks indicated that they mediated neutrophil adhesion and migration responses. The results indicate that lipid factors promoting neutrophil adhesion and migration are generated by the action of thrombin on pulmonary artery endothelial cells. The generation of these factors may contribute to the amplification of the lung inflammatory response after pulmonary intravascular coagulation induced by thrombin.


Asunto(s)
Endotelio Vascular/fisiología , Neutrófilos/fisiología , Arteria Pulmonar/fisiología , Trombina/farmacología , Aminoácidos/análisis , Animales , Anticuerpos Monoclonales/inmunología , Antígenos CD18 , Adhesión Celular , Células Cultivadas , Cromatografía Líquida de Alta Presión , Medios de Cultivo , Endotelio Vascular/efectos de los fármacos , Humanos , Cinética , N-Formilmetionina Leucil-Fenilalanina/farmacología , Neutrófilos/efectos de los fármacos , Factor de Activación Plaquetaria/farmacología , Receptores de Adhesión de Leucocito/inmunología , Receptores de Adhesión de Leucocito/fisiología , Ovinos
12.
J Biol Chem ; 273(34): 22014-20, 1998 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-9705343

RESUMEN

The immunomodulator Betafectin(R) PGG-glucan is a homopolymer of glucose derived from yeast cell walls which has been demonstrated to enhance leukocyte anti-infective activity in vitro and in vivo, without the induction of proinflammatory cytokines. We report here the purification of a PGG-glucan-binding element from human leukocytes and its identification as lactosylceramide, a major glycosphingolipid of neutrophils, which includes the CDw17 epitope. The binding of radiolabeled PGG-glucan to purified lactosylceramide was saturable, specific, and time- and temperature-dependent. Lactosylceramides from human leukocytes were fractionated by high performance liquid chromatography in order to analyze the effect of ceramide structure on binding. A variety of fatty acid chain lengths with varying degrees of unsaturation were found to support binding to radiolabeled PGG-glucan. However, DL-lactosylceramides containing dihydrosphingosine did not bind. Radiolabeled PGG-glucan bound several other neutral glycosphingolipids with a terminal galactose, including galactosylceramide, globotriaosylceramide, and gangliotetraosylceramide. The binding of radiolabeled PGG-glucan to lactosylceramide was not inhibited by glycogen, dextran, mannan, pustulan, laminarin, or a low molecular weight beta-(1-3)-glucan, but was inhibited by high molecular weight beta-(1-3)-glucans and by a monoclonal antibody to lactosylceramide. Although this glycosphingolipid has been shown in numerous reports to bind various microorganisms, this represents the first report of lactosylceramide binding to a macromolecular carbohydrate.


Asunto(s)
Adyuvantes Inmunológicos/metabolismo , Glucanos/metabolismo , Glicoesfingolípidos/metabolismo , Lactosilceramidos/metabolismo , Leucocitos/metabolismo , beta-Glucanos , Antígenos CD/metabolismo , Sitios de Unión , Diferenciación Celular , Humanos , Temperatura , Factores de Tiempo
13.
Antimicrob Agents Chemother ; 45(8): 2340-7, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11451694

RESUMEN

GT160-246, a high-molecular-weight soluble anionic polymer, was tested in vitro and in vivo for neutralization of Clostridium difficile toxin A and B activities. Five milligrams of GT160-246 per ml neutralized toxin-mediated inhibition of protein synthesis in Vero cells induced by 5 ng of toxin A per ml or 1.25 ng of toxin B per ml. In ligated rat ileal loops, 1 mg of GT160-246 neutralized fluid accumulation caused by 5 microg of toxin A. At doses as high as 80 mg/loop, cholestyramine provided incomplete neutralization of fluid accumulation caused by 5 microg of toxin A. GT160-246 protected 80% of the hamsters from mortality caused by infection with C. difficile, whereas cholestyramine protected only 10% of animals. Treatment of C. difficile-infected hamsters with metronidazole initially protected 100% of the hamsters from mortality, but upon removal of treatment, 80% of the hamsters had relapses and died. In contrast, removal of GT160-246 treatment did not result in disease relapse in the hamsters. GT160-246 showed no antimicrobial activity in tests with a panel of 16 aerobic bacteria and yeast and 22 anaerobic bacteria and did not interfere with the in vitro activities of most antibiotics. GT160-246 offers a novel, nonantimicrobial treatment of C. difficile disease in humans.


Asunto(s)
Toxinas Bacterianas/metabolismo , Clostridioides difficile/fisiología , Infecciones por Clostridium/tratamiento farmacológico , Colitis/tratamiento farmacológico , Enterotoxinas/metabolismo , Iones/uso terapéutico , Polímeros/uso terapéutico , Animales , Proteínas Bacterianas/antagonistas & inhibidores , Chlorocebus aethiops , Resina de Colestiramina/uso terapéutico , Infecciones por Clostridium/metabolismo , Infecciones por Clostridium/microbiología , Colitis/metabolismo , Colitis/microbiología , Cricetinae , Humanos , Técnicas In Vitro , Iones/metabolismo , Iones/farmacología , Lactamas/farmacología , Masculino , Metronidazol/uso terapéutico , Pruebas de Sensibilidad Microbiana , Polímeros/metabolismo , Polímeros/farmacología , Ratas , Ratas Wistar , Ácidos Sulfónicos , Tasa de Supervivencia , Células Vero/microbiología
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