RESUMEN
Soil-extracts collected from the ground from under several Euphorbiaceae plants have been known to possess Epstein-Barr virus (EBV)-activating substances which are thought to be one of the environmental co-factors causing nasopharyngeal carcinoma (NPC) in southern part of China and Burkitt's lymphoma (BL) in tropical Africa. Then, a model experiment aimed at chemical characterization of such active substances was carried out using a soil-extract around Sapium sebiferum, a Japanese representative Euphorbiaceae plant. Chromatographic separation guided by the EBV early antigen (EA) inducing activity gave a highly active fraction. Application of this fraction to desorption chemical ionization mass spectrometry identified a major active substance to be 12-O-hexadecanoylphorbol-13-acetate (HPA), which originally occurs in this plant. The method in this model experiment is suggested to be applicable to other samples from the endemic areas of NPC and BL.
Asunto(s)
Herpesvirus Humano 4/efectos de los fármacos , Suelo/análisis , Acetato de Tetradecanoilforbol/aislamiento & purificación , Espectrometría de Masas , Estructura Molecular , Plantas , Acetato de Tetradecanoilforbol/química , Acetato de Tetradecanoilforbol/farmacología , Activación Viral/efectos de los fármacosRESUMEN
3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, 3-carboxy-4-methyl-5-pentyl-2-furanpropionic acid, 3-carboxy-4-methyl-5-ethyl-2-furanpropionic acid and 3-carboxy-5-propyl-2-furanpropionic acid were detected in uremic serum using gas chromatography-mass spectrometry. Mass chromatography revealed that the serum concentrations of the furancarboxylic acids especially 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, were increased in the chronic hemodialysis patients and that the acids could not be removed by conventional hemodialysis due to their strong binding to plasma protein. 3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid was also quantitated in uremic serum by high-performance liquid chromatography. Serum level of the acid in uremic patients showed significant but weak correlation with serum level of urea and duration on hemodialysis. Equilibrium dialysis demonstrated that 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid and 3-carboxy-4-methyl-5-pentyl-2-furanpropionic acid inhibited the bindingof salicylate and 5,5-diphenylhydantoin to albumin. In conclusion, the furancarboxylic acids especially 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid were accumulated in uremic serum as inhibitors of drug binding.
Asunto(s)
Proteínas Portadoras/metabolismo , Furanos/sangre , Propionatos/sangre , Uremia/sangre , Adulto , Anciano , Cromatografía Líquida de Alta Presión , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Diálisis Renal , Salicilatos/metabolismo , Albúmina Sérica/metabolismoAsunto(s)
1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/farmacocinética , Lóbulo Frontal/patología , Isoquinolinas/farmacocinética , Neurotoxinas/farmacocinética , Enfermedad de Parkinson/patología , Tetrahidroisoquinolinas , Biotransformación , Técnicas de Cultivo , Dopamina/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Humanos , Relación Estructura-ActividadAsunto(s)
Errores Innatos del Metabolismo de la Purina-Pirimidina/diagnóstico , Pirimidinas/sangre , Pirimidinas/orina , Timina/análogos & derivados , Uracilo/análogos & derivados , Cromatografía Líquida de Alta Presión/métodos , Femenino , Cromatografía de Gases y Espectrometría de Masas/métodos , Humanos , Lactante , Japón , Masculino , Tamizaje Masivo , Proyectos Piloto , Errores Innatos del Metabolismo de la Purina-Pirimidina/prevención & control , Timina/biosíntesis , Uracilo/sangre , Uracilo/orinaAsunto(s)
Absorción Intestinal/efectos de los fármacos , Sulfonamidas/metabolismo , Tetraciclina/farmacología , Animales , Concentración de Iones de Hidrógeno , Intestino Delgado/efectos de los fármacos , Intestino Delgado/metabolismo , Masculino , Ratas , Ratas Endogámicas , Sulfaguanidina/metabolismoAsunto(s)
Adyuvantes Farmacéuticos/metabolismo , Bencenosulfonatos/metabolismo , Absorción Intestinal/efectos de los fármacos , Ácidos Sulfanílicos/metabolismo , Tetraciclina/farmacología , Animales , Permeabilidad Capilar/efectos de los fármacos , Linfa/metabolismo , Masculino , Ratas , Ácidos Sulfanílicos/sangreAsunto(s)
Acetaminofén , Ácidos Aminosalicílicos , Fenacetina , Fenómenos Químicos , Química , Análisis EspectralAsunto(s)
Ensayos de Selección de Medicamentos Antitumorales , Succinato Deshidrogenasa/antagonistas & inhibidores , Sales de Tetrazolio , Animales , Antineoplásicos/farmacología , Carcinoma de Ehrlich/patología , Ensayos de Selección de Medicamentos Antitumorales/métodos , Ratones , Ratones Endogámicos , Sarcoma 180/patología , Tiazoles , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/patologíaRESUMEN
We quantified indoxyl sulfate in uremic serum by using internal-surface reversed-phase high-performance liquid chromatography. Its concentrations were markedly increased in chronic hemodialysis patients, and were significantly but weakly correlated with the concentrations of creatinine and beta 2-microglobulin in these patients' serum, and with the duration of their hemodialysis treatment. Indoxyl sulfate could not be removed effectively by conventional hemodialysis because of its strong binding to serum albumin. Equilibrium dialysis demonstrated that indoxyl sulfate inhibited the binding of salicylate to albumin, and that 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid inhibited the binding of indoxyl sulfate to albumin. In conclusion, indoxyl sulfate was markedly accumulated in uremic serum, and inhibited drug binding.
Asunto(s)
Indicán/sangre , Uremia/sangre , Albúminas/metabolismo , Cromatografía Líquida de Alta Presión , Furanos/metabolismo , Humanos , Propionatos/metabolismo , Diálisis Renal , Salicilatos/metabolismo , Microglobulina beta-2/análisisRESUMEN
Feasibility for the structural characterization of modified nucleosides in transfer RNA at low microgram levels has been investigated by using continuous-flow frit-fast atom bombardment liquid chromatography/mass spectrometry (frit-FAB LC/MS). Sample of tRNA(Phe) from brewer's yeast (Saccharomyces cerevisiae) was used as a main model, and enzymatically hydrolysed by nuclease P1 and alkaline phosphatase. The resulting nucleoside mixture was separated by using a microbore reversed-phase LC column (150 mm x 0.5 mm i.d.) with an aqueous ammonium acetate-methanol gradient, and the mass spectra were acquired on both positive and negative ionization modes. The modified nucleosides were characterized by comparison of the relative LC elution times with authentic nucleosides, and further confirmed by the structural information from the frit-FAB mass spectra where both molecular and base ions were in general observed as intense peaks in both ionization modes. Typically, 0.06-0.2 A260 units (3-10 micrograms) of isoaccepting tRNA was enough to obtain full-scan mass spectra of modified nucleosides, often occurring at a frequency of one per tRNA molecule using positive ion detection. The LC/MS system was used to screen modified nucleosides in tRNA of the extremely thermophilic microorganism Pyrodictium occultum.
Asunto(s)
Nucleósidos/química , ARN Bacteriano/química , ARN de Hongos/química , ARN de Transferencia/química , Archaea/metabolismo , Cromatografía Líquida de Alta Presión , Escherichia coli/metabolismo , Hidrólisis , Saccharomyces cerevisiae/metabolismo , Espectrometría de Masa Bombardeada por Átomos Veloces , Espectrofotometría UltravioletaRESUMEN
Ribose-methylated dinucleotides of the type NmpN' derived from digestion of tRNA with RNase T2 were separated and characterized by directly combined liquid chromatography--mass spectrometry (LC-MS) with a continuous-flow frit-fast atom bombardment (frit-FAB) interface. Prediction of NmpN' peaks was readily made by comparison of the LC profile with that of comparative nuclease P1 digest. The identity of the candidate peaks including NmpN' was further recognized by the mass spectra, in which NmpN' showed intense molecular-related ions, in addition to sequence-specific fragment ions, to verify the chemical structures in both positive- and negative-ion modes. The method was applied to screening NmpN' (and NmpN' mpN") in tRNA from the extremely thermophilic archaeon Pyrodictium occultum.
Asunto(s)
Archaea/química , ARN de Transferencia/análisis , Ribonucleótidos/análisis , Cromatografía Liquida , Hidrólisis , Metilación , ARN de Transferencia de Fenilalanina/metabolismo , Saccharomyces cerevisiae/química , Espectrometría de Masa Bombardeada por Átomos VelocesRESUMEN
A major protein-bound ligand in the serum of chronic hemodialysis patients was isolated from heat-deproteinized uremic serum by "high-performance" liquid chromatography (HPLC). The isolated compound was identified as 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid by use of liquid secondary-ion mass spectrometry and gas chromatography-mass spectrometry. On HPLC, an authentic sample of this compound showed a retention time identical to that of the protein-bound ligand peak. The concentration of the furancarboxylic acid in serum, as estimated by HPLC, is markedly greater in chronic hemodialysis patients than in normal subjects.