RESUMEN
Arterial stiffness is a pathological event related to arteriosclerosis that is also closely related to oxidative stress. The cardio-ankle vascular index (CAVI) is a novel arteriosclerotic index that has been used to detect arterial stiffness. However, the association between CAVI and oxidative stress has not yet been elucidated, especially in patients with risk of metabolic disorders. The aim of this study was to investigate the correlation between arterial stiffness by CAVI and biomarkers of oxidative stress. A total of 83 participants were enrolled in this study. Venous blood samples were collected for measurement of plasma oxidative biomarkers. All participants were examined for CAVI score. The univariate analysis showed that age (p < 0.001), systolic blood pressure (SBP) (p = < 0.001), plasma triglyceride (p = 0.02), plasma glucose (p = 0.003) are related to CAVI value. However, the multivariate analysis showed that age was the only significant independent factor related to the CAVI value. In addition, the CAVI and plasma malondialdehyde (MDA) levels showed a positive correlation (r = 0.29, p < 0.01) while, the CAVI was negatively correlated with catalase (CAT) (r = -0.4, p < 0.001) and GPx (r = -0.60, p < 0.001). In conclusion, this study demonstrated that age is the most influential factor for assessing arterial stiffness by the CAVI method, which is possibly due to the increase in oxidative stress.
Asunto(s)
Arteriosclerosis/sangre , Rigidez Vascular , Adulto , Anciano , Tobillo/irrigación sanguínea , Arteriosclerosis/diagnóstico , Biomarcadores/sangre , Catalasa/sangre , Femenino , Glutatión Peroxidasa/sangre , Humanos , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Estrés Oxidativo , Adulto JovenRESUMEN
The product of the ARO10 gene from Saccharomyces cerevisiae was initially identified as a thiamine diphosphate-dependent phenylpyruvate decarboxylase with a broad substrate specificity. It was suggested that the enzyme could be responsible for the catabolism of aromatic and branched-chain amino acids, as well as methionine. In the present study, we report the overexpression of the ARO10 gene product in Escherichia coli and the first detailed in vitro characterization of this enzyme. The enzyme is shown to be an efficient aromatic 2-keto acid decarboxylase, consistent with it playing a major in vivo role in phenylalanine, tryptophan and possibly also tyrosine catabolism. However, its substrate spectrum suggests that it is unlikely to play any significant role in the catabolism of the branched-chain amino acids or of methionine. A homology model was used to identify residues likely to be involved in substrate specificity. Site-directed mutagenesis on those residues confirmed previous studies indicating that mutation of single residues is unlikely to produce the immediate conversion of an aromatic into an aliphatic 2-keto acid decarboxylase. In addition, the enzyme was compared with the phenylpyruvate decarboxylase from Azospirillum brasilense and the indolepyruvate decarboxylase from Enterobacter cloacae. We show that the properties of the two phenylpyruvate decarboxylases are similar in some respects yet quite different in others, and that the properties of both are distinct from those of the indolepyruvate decarboxylase. Finally, we demonstrate that it is unlikely that replacement of a glutamic acid by leucine leads to discrimination between phenylpyruvate and indolepyruvate, although, in this case, it did lead to unexpected allosteric activation.
Asunto(s)
Carboxiliasas/metabolismo , Saccharomyces cerevisiae/enzimología , Tiamina Pirofosfato/metabolismo , Carboxiliasas/genética , Cromatografía en Gel , Electroforesis en Gel de Poliacrilamida , Espectrometría de Masas , Modelos Moleculares , Mutagénesis , Especificidad por SustratoRESUMEN
OBJECTIVE: The aim of this study was to investigate the stability of fortified cefazolin sodium ophthalmic solutions (50 mg mL⻹) extemporaneously prepared in commercial artificial tears containing 2 different types of preservatives, namely the surfactants and oxidants. METHODS: Fortified cefazolin sodium solutions were prepared by reconstituting cefazolin for injection with sterile water and further diluted with Tears Naturale II or Natear, 2 commercial artificial tears containing polyquaternium-1 and sodium perborate, respectively, as preservatives. The solutions were then kept at room temperature (28°C) or in the refrigerator (4°C). During the 28-day period, the formulations were periodically examined for the physical appearance, pH, and the remaining drug concentrations. The antibacterial potency was evaluated as the minimal inhibitory concentration against Staphylococcus aureus strain ATCC 29923 by broth dilution technique. The activity of the preservatives was demonstrated by antimicrobial effectiveness tests. On day 28, the microbial contamination in the preparations was tested. RESULTS: The stability profiles of cefazolin solutions prepared in Tears Naturale II, Natear, and water were not different, but they were significantly influenced by the storage temperature. The refrigerated formulations showed no loss of drug and antibacterial potency as well as alteration of physical appearance and pH throughout the 28 days. In contrast, those kept at room temperature showed gradual change in color and odor. The degradation of drug exceeded 10% from day 3 and the decrease of antibacterial potency could be observed at week 3. All cefazolin solutions prepared in artificial tears retained the antimicrobial activity of preservatives and were free from bacterial and fungal contamination throughout the 28-day period of study. CONCLUSIONS: Cefazolin sodium ophthalmic solutions can be extemporaneously prepared in Tears Naturale II or Natear without the influence from different types of preservatives used in these vehicles. The formulation is physically and chemically stable and retains the antibacterial potency for at least 28 days in the refrigerator.
Asunto(s)
Antibacterianos/farmacología , Cefazolina/farmacología , Cefazolina/administración & dosificación , Contaminación de Medicamentos , Estabilidad de Medicamentos , Almacenaje de Medicamentos , Concentración de Iones de Hidrógeno , Pruebas de Sensibilidad Microbiana , Soluciones Oftálmicas/química , Oxidantes/metabolismo , Oxidantes/farmacología , Conservadores Farmacéuticos/metabolismo , Staphylococcus aureus/efectos de los fármacos , Tensoactivos/metabolismo , Tensoactivos/farmacología , TemperaturaRESUMEN
While aminothiols produce weak purple-colored reactions with ninhydrin, we demonstrate for the first time that this color could be intensely developed. Using a D-penicillamine paradigm, adsorption of this compound via a disulfide bond onto thiol-reactive solid prior to ninhydrin reaction allowed spectrophotometrical monitoring of the supernatant at 570 nm. Compared with off-solid method, this approach expanded the linear concentration range to 50-600 microg mL(-1) and enhanced the sensitivity so that D-penicillamine with the concentrations of less than 100 microg mL(-1) could be accurately quantitated by using a second-order polynomial calibration curve. Additionally, this assay was unaffected by disulfide adduct interference, highlighting its potential for the analysis of D-penicillamine as well as other aminothiols.
Asunto(s)
Ninhidrina/química , Penicilamina/análisis , Penicilamina/química , Compuestos de Sulfhidrilo/química , Colorimetría , Límite de Detección , Estructura Molecular , Espectrofotometría UltravioletaRESUMEN
Following induction with D-phenylglycine both d-phenylglycine aminotransferase activity and benzoylformate decarboxylase activity were observed in cultures of Pseudomonas stutzeri ST-201. Induction with benzoylformate, on the other hand, induced only benzoylformate decarboxylase activity. Purification of the benzoylformate decarboxylase, followed by N-terminal sequencing, enabled the design of probes for hybridization with P. stutzeri ST-201 genomic DNA libraries. Sequencing of two overlapping genomic DNA restriction fragments revealed two open reading frames which were denoted dpgB and dpgC. Sequence alignments suggested that the genes encoded a thiamin-diphosphate-dependent decarboxylase and an aldehyde dehydrogenase, respectively. Both genes were isolated and expressed in Escherichia coli. The dpgB gene product was confirmed as a benzoylformate decarboxylase while the dpgC gene product was characterized as a NAD+/NADP+-dependent benzaldehyde dehydrogenase. In keeping with their high sequence identities (both greater than 85%) the kinetic properties of the two enzymes were similar to those of the homologous enzymes in the mandelate pathway of Pseudomonas putida ATCC 12633. However, Pseudomonas stutzeri ST-201 was unable to grow on either isomer of mandelate, and sequencing indicated that the dpgB gene did not form part of an operon. Thus it appears that the two enzymes form part of a d-phenylglycine, rather than mandelate, degrading pathway.