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Search Results: 1 - 10 of 555209 matches for " B.; García-Herrero "
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Theoretical Evaluation of Both Unknown Substrate Concentrations and Enzyme Kinetic Constants of Metabolic Cycles  [PDF]
Antonio Sillero, Víctor García-Herrero
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.88045
Abstract: A formula has been deduced, and named as 2ESKV, relating the concentration of two consecutive substrates of a metabolic cycle with the kinetic constants of the two enzymes involved in their synthesis and degradation. After application of formula 2ESKV to consecutive pairs of substrates and enzymes, a system of interrelated equations was obtained allowing a great variety of theoretical postulates to calculate, back and forth: bunches of unknown enzyme kinetic constants and substrate concentrations, from complementary sets of known data. This vision of a metabolic cycle is of partial application to irreversible pathways and can be useful for modeling and understanding of metabolomics data. To our knowledge, the formula 2ESKV is here described for the first time.
Closed and Open Metabolic Cycles: Transition Time  [PDF]
Antonio Sillero, Víctor García-Herrero
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.92009
Abstract: A metabolic cycle can be viewed as a central core and its branches. The central core is here firstly considered as a pre-closed metabolic cycle (CMC), with a unique first substrate, but with no input or output of other components. By contrast, the metabolic cycles in nature are open metabolic cycles (OMC) with output and input of external substrates (through “metabolic branches”), modulating continuously the enzyme activities and the total concentration of their substrates thorough complex regulatory phenomena. In this work, the transition from a Closed to an Open metabolic cycle has been simulated by a consecutive entry and exit of two components through the catalytic action of two enzymes. It is known that after any alteration of the initial conditions, the cycles need a time to reach new equilibrium. We have measured the changes of transition time (T.T.) values in 81 models of CMC differing in Km or Vmax values. In general, the T.T. tends to be shorter in cycles with preponderant lower Km and higher Vmax values. Further, Mathematica refinement for the estimation of transition time from the data previously calculated can be obtained with the use of the command Interpolating Function.
Metabolic Cycles: Effect of a Simultaneous Input and Output of Two Substrates  [PDF]
Antonio Sillero, Víctor García-Herrero
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.913053
Abstract: The metabolic cycle firstly considered here is composed of a unique initial substrate, six enzymes, and five empty boxes to accommodate the substrates derived from the transformation of the initial substrate. This cycle was considered as a pre-Closed Metabolic Cycle (CMC). Using this model, the influence of changing the kinetic constant values of any enzyme on the substrate concentration was explored. This model was transformed into an open metabolic cycle (OMC) by the input and output of two metabolites catalyzed by two external enzymes. In this case, the relative rates of input and output of metabolites were also examined; it can be concluded that the OMC cycles form delicate and fragile structures which can be theoretically disrupted, making them metabolically unfeasible.
Desprendimiento seroso de mácula como manifestación atípica en la enfermedad del ara?azo del gato
Asensio-Sánchez,V.M.; Rodríguez-Delgado,B.; García-Herrero,E.; Cabo-Vaquera,V.; García-Loygorri,C.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2006, DOI: 10.4321/S0365-66912006001200009
Abstract: case report: a 58-year-old woman presented with 0.1 visual acuity in the left eye associated with a serous retinal detachment of the macula as the only ocular manifestation of cat scratch disease. this diagnosis was made by serum antibody titers and the clinical course. discussion: although uncommon, cat scratch disease should be considered in patients with a serous detachment in the macula region of the retina.
Microalbuminuria y retinopatía diabética
Asensio-Sánchez,V.M.; Rodríguez-Delgado,B.; García-Herrero,E.; Cabo-Vaquera,V.; García-Loygorri,C.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2008, DOI: 10.4321/S0365-66912008000200005
Abstract: objective: to study the prevalence of microalbuminuria and its association with more severe diabetic retinopathy in a group of insulin-dependent diabetic patients. materials and methods: during the period of january 1998 to december 2005 we examined 360 insulin-dependent diabetic patients with at least five years of evolution. we evaluated the presence of microalbuminuria by immunoanalysis. patients were evaluated by direct and indirect ophthalmoscopy and classified as non-retinopathy, non-proliferative, severe non-proliferative/proliferative, or macular edema. results: in this study, 24.1% of patients had microalbuminuria. most of the patients with microalbuminuria and macroalbuminuria were male and had a longer history of diabetes. microalbuminuria was associated with more severe diabetic retinopathy. conclusions: all patients with insulin-dependent diabetes of at least five years? evolution should undergo an evaluation of renal function including tests for microalbuminuria. in the presence of microalbuminuria an ophthalmologic follow-up may be particularly important.
Alucinaciones visuales secundarias al tratamiento con ciprofloxacino
Asensio-Sánchez,V.M.; Rodríguez-Delgado,B.; García-Herrero,E.; Cabo-Vaquera,V.; García-Loygorri,C.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2007, DOI: 10.4321/S0365-66912007000500009
Abstract: case report: we describe a case of a 74-year-old woman who experienced visual hallucinations after ciprofloxacin administration, when she was also taking theophylline, which resolved on cessation of the ciprofloxacin. discussion: although uncommon, all ophthalmologists should be aware of this potential problem and be familiar with the adverse visual effects which may occur in patients simultaneously administered quinolones and theophylline.
HLA-A24: factor de riesgo en retinopatía diabética proliferante
Asensio-Sánchez,V.M.; Rodríguez-Delgado,B.; García-Herrero,E.; Cabo-Vaquera,V.; García-Loygorri,C.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2007, DOI: 10.4321/S0365-66912007001200007
Abstract: objective: proliferative diabetic retinopathy (pdr) is characterized by a progressive visual impairment in young people. human leucocyte antigen (hla)-a24 is a well-established factor associated with the pancreatic islets of langerhans lost in this process. our aim was to study further the relationship of the hla-a24 associated with pdr. materials and methods: we evaluated a group of patients with pdr (n=95) and a healthy control group (n= 60). hla-a24 for each participant in the study was determined by molecular hybridization techniques. results: the control group showed a lower frequency of hla-a24 compared with the pdr group (p = 0.043). hla-a24 was associated with pdr (or = 5.4; 95% ci= 3.2-7.6; p< 0.001). conclusions: hla-a24 is not a protective factor for pdr, but is a risk factor of its development.
Coriorretinopatía serosa central como manifestación extradigestiva de infección gástrica por helicobacter pylori
Asensio-Sánchez,V.M.; Rodríguez-Delgado,B.; García-Herrero,E.; Cabo-Vaquera,V.; García-Loygorri,C.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2008, DOI: 10.4321/S0365-66912008000300009
Abstract: objective: helicobacter pylori (hp) gastric infection has been implicated as an important factor in occlusive arterial pathology. nowadays, it is suspected that central serous chorioretinopathy (csc) is due to a multifocal vascular occlusive disease of the choriocapillaris. the aim of this study was to determine the relation between gastric hp infection and csc. materials and methods: we evaluated a group of 16 patients with csc and 20 controls. hp infection was assessed by the 13c-urea breath test (ubt). clinical csc diagnosis was confirmed by fundus biomicroscopy and fluorescein angiography. results: out of 16 patients with csc, 11 (68.75%) were males and 5 (31.25%) females, with a mean age of 46.3 years. hp infection was positive in 11 patients (68.75%) and negative in 5 (31.25%). men were hp-positive (hp+) in 72.7% of cases, compared to women who were hp+ in 60% of cases. the difference in prevalence of hp between the csc-group (68.75%) and the control-group (30%) was found to be statistically significant (p< 0.05). hp+ patients had more gastric pain than hp negative (hp-) patients (72.73% vs 20%). conclusions: these results indicate a possible statistical association between helicobacter pylori gastric infection and csc. hp should thus be considered a risk factor in csc patients.
HLA-A24: factor de riesgo en retinopatía diabética proliferante HLA-A24: risk factor in proliferante diabetic retinopathy
V.M. Asensio-Sánchez,B. Rodríguez-Delgado,E. García-Herrero,V. Cabo-Vaquera
Archivos de la Sociedad Espa?ola de Oftalmología , 2007,
Abstract: Objetivo: La retinopatía diabética proliferante (RDP) se caracteriza por pérdida de la visión en la población joven. Está bien establecido que el antígeno leucocitario humano (HLA)-A24 es un factor de riesgo para la pérdida total de las células del páncreas. Nuestro objetivo es estudiar la asociación del HLA-A24 con la RDP. Material y método: Se estudió un grupo de pacientes con RDP (n= 95) y un grupo control (n= 60). A todos se les determinó el HLA-A24 mediante técnicas hibridación molecular. Resultados: El grupo control mostró menos frecuencia de HLA-A24 que el grupo con RDP (p= 0,043). El HLA-A24 se asoció a retinopatía diabética proliferante (OR = 5,4; 95% CI= 3,2-7,6; p< 0,001). Conclusiones: El HLA-A24 no es un factor de protección para la retinopatía diabética proliferante, es un factor de riesgo para desarrollarla. Objective: Proliferative diabetic retinopathy (PDR) is characterized by a progressive visual impairment in young people. Human leucocyte antigen (HLA)-A24 is a well-established factor associated with the pancreatic islets of Langerhans lost in this process. Our aim was to study further the relationship of the HLA-A24 associated with PDR. Materials and methods: We evaluated a group of patients with PDR (n=95) and a healthy control group (n= 60). HLA-A24 for each participant in the study was determined by molecular hybridization techniques. Results: The control group showed a lower frequency of HLA-A24 compared with the PDR group (p = 0.043). HLA-A24 was associated with PDR (OR = 5.4; 95% CI= 3.2-7.6; p< 0.001). Conclusions: HLA-A24 is not a protective factor for PDR, but is a risk factor of its development.
Alucinaciones visuales secundarias al tratamiento con ciprofloxacino Visual hallucinations secondary to ciprofloxacin treatment
V.M. Asensio-Sánchez,B. Rodríguez-Delgado,E. García-Herrero,V. Cabo-Vaquera
Archivos de la Sociedad Espa?ola de Oftalmología , 2007,
Abstract: Caso clínico: Se describe el caso de una mujer de 74 a os que tuvo alucinaciones visuales después de la administración de ciprofloxacino cuando estaba tomando una teofilina, resolviéndose el cuadro alucinatorio cuando se suspendió el ciprofloxacino. Discusión: Aunque es poco frecuente, todos los oftalmólogos deberían estar alerta y conocer los posibles efectos adversos visuales en pacientes con tratamiento simultáneo de quinolonas y teofilinas. Case report: We describe a case of a 74-year-old woman who experienced visual hallucinations after ciprofloxacin administration, when she was also taking theophylline, which resolved on cessation of the ciprofloxacin. Discussion: Although uncommon, all ophthalmologists should be aware of this potential problem and be familiar with the adverse visual effects which may occur in patients simultaneously administered quinolones and theophylline.
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