Mónica Espinoza

Publications (5)9.61 Total impact

• Source

  Available from: Claudio Olea-Azar

  Article: Determination of reactions between free radicals and selected Chilean wines and transition metals by ESR and UV-vis technique.

  Mónica Espinoza, Claudio Olea-Azar, Hernán Speisky, Jorge Rodríguez
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  ABSTRACT: Four different types of Chilean wines (Cabernet Sauvignon, Merlot, Carmenere and Syrah) were selected and examined in their free radical scavenging capacities by electron spin resonance (ESR) and spectrophotometric methods. The free radical scavenging properties were evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical, 2,6-di-tert-butyl-alpha-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy (Galvinoxyl) radical and hydroxyl radical (HO*). The possible effect on these scavenging properties of added transition metals to these wines was evaluated. Among the wines evaluated, Cabernet Sauvignon was the one with the highest activity against all radicals tested. The presence of added copper or iron to wines resulted in a reduced free radical scavenging capacity for all type of wines studied. The formation of redox inactive complexes between polyphenols of wine and transition metals is the possible cause of this reduction in antioxidant activity.
  Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 07/2008; 71(5):1638-43. · 2.10 Impact Factor
• Article: A comparative study of two different methods for the detection of latent tuberculosis in HIV-positive individuals in Chile.

  María Elvira Balcells, Carlos M Pérez, Leonardo Chanqueo, Martín Lasso, Marcela Villanueva, Mónica Espinoza, Luis Villarroel, Patricia García
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  ABSTRACT: To compare the performance of two tests for diagnosing latent tuberculosis (TB) infection in the HIV-positive population in Chile, in order to better identify the subjects who might benefit from TB chemoprophylaxis. This was a cross-sectional study among individuals attending three HIV outpatient clinics in Santiago, tested with a 2-TU purified protein derivative, QuantiFERON((R))-TB Gold 'in-tube' (QFT-G), and a chest X-ray. A total of 116 subjects were enrolled in the study, having a mean CD4 count of 393cells/microl (range 100-977). The tuberculin skin text (TST; 5mm cutoff) and QFT-G results were positive in 10.9% and 14.8% of the individuals, respectively, with moderate agreement between both tests (kappa=0.59). A history of both known TB exposure (odds ratio (OR) 3.46, 95% confidence interval (CI) 1.02-11.22) and past TB (OR 4.31, 95% CI 1.13-15.5) were associated with a positive QFT-G result. Only past TB was significantly associated with a positive TST result (OR 6.63, 95% CI 1.62-26.3). Among the subjects with TST<5mm, 8.2% were positive by QFT-G test. These individuals had a lower mean CD4 cell count than those detected positive by both tests (328cells/microl and 560cells/microl, respectively, p=0.03). In this population of HIV-infected individuals, QFT-G and TST showed an acceptable level of agreement, although QFT-G appears less affected by more advanced immunosuppression.
  International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases 07/2008; 12(6):645-52. · 2.17 Impact Factor
• Article: [Usefulness of the determination of IgG and IgM antibodies by ELISA and immunocapture in a clinical series of human brucellosis].

  Carolina Aranís J, Jorge Oporto C, Mónica Espinoza, Ingrid Riedel K, Carlos Pérez C, Patricia García C
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  ABSTRACT: The diagnostic difficulties of brucellosis makes the evaluation of new diagnostic tests necessary. Evaluation of different commercial tests in the serological diagnosis of brucellosis by ELISA and immunocapture antibodies in a clinical series of patients with brucellosis of the Health Network of the Catholic University of Chile. All the serums received in the Laboratory of Microbiology for suspicion of brucellosis during five years were studied. Two groups were obtained, one that fulfilled diagnostic criteria for brucellosis [clinical evidence, and/or positive blood culture and/or seroagglutination test (SAT) in titers > 1/160] and the control group. Each serum sample was analyzed using irnmunocapture-agglutination test (Brucellacapt), ELISA IgM and IgG. Of 10 patients with brucellosis, the serologic results were: 8/10 positives for ELISA IgG, 7/10 for Brucellacapt and SAT, and 5/10 for ELISA IgM. ELISA IgG alone was superior than SAT. The combination ELISA IgG/ Brucellacapt reaches the best detection performance (9/10) and can be an alternative to SAT.
  Revista chilena de infectologia: organo oficial de la Sociedad Chilena de Infectologia 04/2008; 25(2):116-21. · 0.45 Impact Factor
• Article: Differential signalling for enhanced hexose uptake by interleukin (IL)-3 and IL-5 in male germ cells.

  M Cecilia Rauch, Mónica Brito, Angara Zambrano, Mónica Espinoza, Marisol Pérez, Alejandro Yañez, Coralia I Rivas, Juan Carlos Slebe, Juan Carlos Vera, Ilona I Concha
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  ABSTRACT: We studied the expression and function of the IL (interleukin)-3 and IL-5 family of receptors in male germ cells. RT (reverse transcription)-PCR showed expression of mRNAs encoding the alpha and beta subunits of the IL-3 and IL-5 receptors in human testis, and the presence of IL-3 and IL-5 receptors alpha and beta proteins was confirmed by immunoblotting with anti-alpha and anti-beta antibodies. The immunolocalization studies showed expression of these receptors in the germ line in the human testis and in human and bovine ejaculated spermatozoa. Functional studies with bull spermatozoa indicated that IL-3 signalled for increased uptake of hexoses in these cells at picomolar concentrations compatible with expression of functional high-affinity IL-3 receptors in these cells. In contrast, IL-5 failed to induce increased hexose uptake in bull spermatozoa. Experiments using HL-60 eosinophils that express functional IL-3 and IL-5 receptors confirmed that IL-3, but not IL-5, signalled for increased hexose uptake. Our findings suggest that differential signalling for increased hexose uptake by heteromeric high-affinity IL-3 and IL-5 receptors in mammalian spermatozoa is a property that depends on the identity of the alpha-subunit forming part of the alphabeta-complex and is not a property specific to the germ cells.
  Biochemical Journal 08/2004; 381(Pt 2):495-501. · 4.90 Impact Factor
• Article: Determination of reactions between free radicals and selected Chilean wines and transition metals by ESR and UV-vis technique

  Mónica Espinoza, Claudio Olea Azar, Hernán Speisky C, Jorge Rodríguez
  [show abstract] [hide abstract]
  ABSTRACT: Four different types of Chilean wines (Cabernet Sauvignon, Merlot, Carmenere and Syrah) were selected and examined in their free radical scavenging capacities by electron spin resonance (ESR) and spectrophotometric methods. The free radical scavenging properties were evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH center dot) radical, 2,6-di-tert-butyl-alpha-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy (Galvinoxyl) radical and hydroxyl radical (HO center dot). The possible effect on these scavenging properties of added transition metals to these wines was evaluated. Among the wines evaluated, Cabernet Sauvignon was the one with the highest activity against all radicals tested. The presence of added copper or iron to wines resulted in a reduced free radical scavenging capacity for all type of wines studied. The formation of redox inactive complexes between polyphenols of wine and transition metals is the possible cause of this reduction in antioxidant activity.