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1.
QJM ; 114(9): 642-647, 2021 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-33486512

RESUMEN

BACKGROUND: COVID-19 has challenged the health system organization requiring a fast reorganization of diagnostic/therapeutic pathways for patients affected by time-dependent diseases such as acute coronary syndromes (ACS). AIM: To describe ACS hospitalizations, management, and complication rate before and after the COVID-19 pandemic was declared. DESIGN: Ecological retrospective study. Methods: We analyzed aggregated epidemiological data of all patients > 18 years old admitted for ACS in twenty-nine hub cardiac centers from 17 Countries across 4 continents, from December 1st, 2019 to April 15th, 2020. Data from December 2018 to April 2019 were used as historical period. RESULTS: A significant overall trend for reduction in the weekly number of ACS hospitalizations was observed (20.2%; 95% confidence interval CI [1.6, 35.4] P = 0.04). The incidence rate reached a 54% reduction during the second week of April (incidence rate ratio: 0.46, 95% CI [0.36, 0.58]) and was also significant when compared to the same months in 2019 (March and April, respectively IRR: 0.56, 95%CI [0.48, 0.67]; IRR: 0.43, 95%CI [0.32, 0.58] p < 0.001). A significant increase in door-to-balloon, door-to-needle, and total ischemic time (p <0.04 for all) in STEMI patents were reported during pandemic period. Finally, the proportion of patients with mechanical complications was higher (1.98% vs. 0.98%; P = 0.006) whereas GRACE risk score was not different. CONCLUSIONS: Our results confirm that COVID-19 pandemic was associated with a significant decrease in ACS hospitalizations rate, an increase in total ischemic time and a higher rate of mechanical complications on a international scale.


Asunto(s)
Síndrome Coronario Agudo , COVID-19 , Síndrome Coronario Agudo/epidemiología , Síndrome Coronario Agudo/terapia , Adolescente , Hospitalización , Humanos , Pandemias , Estudios Retrospectivos , SARS-CoV-2
2.
Rev Esp Quimioter ; 34(2): 100-106, 2021 Apr.
Artículo en Español | MEDLINE | ID: mdl-33491408

RESUMEN

OBJECTIVE: One of the most aggressive microorganisms in infective endocarditis (IE) is Staphylococcus aureus. We analyse the resistance of S. aureus to antibiotics and its impact on the clinical course of IE in a recent 15-year period. METHODS: Retrospective study of patients with IE in a university hospital from 2005 to 2019. Bivariate and multivariate analysis of severity at admission, comorbidities, minimum inhibitory concentrations (MIC) and mortality. RESULTS: Of the 293 IE cases, 66 (22.5%) were due to S. aureus, and 21 (7.2%) were methicillin-resistant S. aureus (MRSA). The prevalence of strains with a MIC to vancomycin ≥ 1mg/L increased from 4.8% to 63.6% (p <0.001) and the cases of MRSA from 38 to 27.3% (p = 0.045). Older age (p= 0.02), comorbidity (p <0.01) and nosohusial origin (p = 0.01), were factors associated with MRSA. But the antimicrobial resistance and severity on admission were not associated with exitus; predictive factors were the right-sided IE (OR = 0.08; 95% CI: 0.01-0.51), comorbidities (OR per Charlson index point = 1.30; 95% CI: 1.01-1.69) and creatinine on admission (OR per mg / dL = 1.56; 95% CI = 1.01- 2.35; p = 0.04). CONCLUSIONS: We have experienced an increase in IE cases with MIC to vancomycin ≥ 1mg/L, without significant variation in infections due to MRSA. Antimicrobial resistance was not associated with mortality, but comorbidity and left involvement were predictive factors.


Asunto(s)
Endocarditis , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Anciano , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana , Endocarditis/tratamiento farmacológico , Hospitales Universitarios , Humanos , Pruebas de Sensibilidad Microbiana , Estudios Retrospectivos , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus
3.
Med Intensiva (Engl Ed) ; 44(8): 475-484, 2020 Nov.
Artículo en Inglés, Español | MEDLINE | ID: mdl-31362838

RESUMEN

OBJECTIVE: Current guidelines recommend a risk-adjusted early invasive strategy (EIS) in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). The present study assesses the application if this strategy, the conditioning factors and prognostic impact upon patients with NSTEACS admitted to Intensive Cardiac Care Units (ICCU). DESIGN: A prospective cohort study was carried out. SETTING: The ICCUs of 8 hospitals in Catalonia (Spain). PATIENTS: Consecutive patients with NSTEACS between October 2017 and March 2018. The risk profile was defined by the European Society of Cardiology criteria. INTERVENTIONS: EIS was defined as the performance of coronary angiography within the first 6hours in patients at very high-risk or within 24hours in high-risk patients. OUTCOME VARIABLES: Mortality or readmission at 6 months. RESULTS: A total of 629 patients were included (mean age 66.6 years), of whom 225 (35.9%) were at very high risk, and 392 (62.6%) at high risk. Most patients (96.2%) underwent an invasive strategy. EIS was performed in 284 patients (45.6%), especially younger patients with fewer comorbidities. These patients had a shorter ICCU and hospital stay, as well as a lesser incidence of ACS, revascularization and death or readmission at 6 months. After adjusting for confounders, the association between EIS and death or readmission at 6 months remained significant (hazard ratio: .66, 95% confidence interval .45-.97; P=.035). CONCLUSIONS: The EIS was performed in a minority of NSTEACS admitted to ICCU, being associated with better outcomes.

4.
J Phys Chem A ; 123(40): 8496-8505, 2019 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-31509408

RESUMEN

Rotationally inelastic collisions of O2 with He in the 10-34 K thermal range are investigated by means of an experimental procedure based on supersonic gas jets probed by Raman spectroscopy. The procedure employs a kinetic master equation (MEQ) that describes the time evolution of the rotational populations of O2 along supersonic jets of O2 and He mixtures. The MEQ is expressed in terms of experimental quantities (number density and rotational populations) measured here, and state-to-state rate coefficients for the O2:He inelastic collisions calculated here, plus those for O2:O2 collisions from the literature. An agreement with the experiments is accomplished for temperatures between 10 and 34 K. Within this thermal range, the role of the fine structure due to electron spin in the collision dynamics of O2 is discussed.

5.
Nat Commun ; 8: 15461, 2017 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-28580940

RESUMEN

Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.

6.
Auton Neurosci ; 205: 12-20, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28254195

RESUMEN

The application of sodium cyanide (NaCN) to the carotid body receptors (CBR) (CBR stimulation) induces rapid blood hyperglycemia and an increase in brain glucose retention. The commissural nucleus tractus solitarius (cNTS) is an essential relay nucleus in this hyperglycemic reflex; it receives glutamatergic afferents (that also release brain derived neurotrophic factor, BDNF) from the nodose-petrosal ganglia that relays CBR information. Previous work showed that AMPA in NTS blocks hyperglycemia and brain glucose retention after CBR stimulation. In contrast, BDNF, which attenuates glutamatergic AMPA currents in NTS, enhances these glycemic responses. Here we investigated the combined effects of BDNF and AMPA (and their antagonists) in NTS on the glycemic responses to CBR stimulation. Microinjections of BDNF plus AMPA into the cNTS before CBR stimulation in anesthetized rats, induced blood hyperglycemia and an increase in brain arteriovenous (a-v) of blood glucose concentration difference, which we infer is due to increased brain glucose retention. By contrast, the microinjection of the TrkB antagonist K252a plus AMPA abolished the glycemic responses to CBR stimulation similar to what is observed after AMPA pretreatments. In BDNF plus AMPA microinjections preceding CBR stimulation, the number of c-fos immunoreactive cNTS neurons increased. In contrast, in the rats microinjected with K252a plus AMPA in NTS, before CBR stimulation, c-fos expression in cNTS decreased. The expression of AMPA receptors GluR2/3 did not change in any of the studied groups. These results indicate that BDNF in cNTS plays a key role in the modulation of the hyperglycemic reflex initiated by CBR stimulation.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/metabolismo , Cuerpo Carotídeo/efectos de los fármacos , Cuerpo Carotídeo/metabolismo , Hiperglucemia/metabolismo , Núcleo Solitario/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/metabolismo , Animales , Factor Neurotrófico Derivado del Encéfalo/administración & dosificación , Ensayo de Inmunoadsorción Enzimática , Glucosa/metabolismo , Hiperglucemia/inducido químicamente , Hiperglucemia/patología , Inmunohistoquímica , Masculino , Microinyecciones , Neurotransmisores/farmacología , Proteínas Proto-Oncogénicas c-fos/metabolismo , Distribución Aleatoria , Ratas Wistar , Receptor trkB/agonistas , Receptor trkB/antagonistas & inhibidores , Receptor trkB/metabolismo , Receptores AMPA/agonistas , Receptores AMPA/antagonistas & inhibidores , Receptores AMPA/metabolismo , Cianuro de Sodio/farmacología , Núcleo Solitario/citología , Núcleo Solitario/efectos de los fármacos , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/administración & dosificación
7.
Semergen ; 43(3): 175-181, 2017 Apr.
Artículo en Español | MEDLINE | ID: mdl-27344582

RESUMEN

INTRODUCTION: The introduction of electronic medical records and computer media in clinics, has influenced the physician-patient relationship. These modifications have many advantages, but there is concern that the computer has become too important, going from a working tool to the centre of our attention during the clinical interview, decreasing doctor interaction with the patient. The objective of the study was to estimate the percentage of time that family physicians spend on computer media compared to interpersonal communication with the patient, and whether this time is modified depending on different variables such as, doctor's age or reason for the consultation. MATERIAL AND METHODS: An observational and descriptive study was conducted for 10 weeks, with 2 healthcare centres involved. The researchers attended all doctor- patient interviews, recording the patient time in and out of the consultation. Each time the doctor fixed his gaze on computer media the time was clocked. RESULTS: A total of 436 consultations were collected. The doctors looked at the computer support a median 38.33% of the total duration of an interview. Doctors of 45 years and older spent more time fixing their eyes on computer media (P<.05). CONCLUSIONS: Family physicians used almost 40% of the consultation time looking at computer media, and depends on age of physician, number of queries, and number of medical appointments.


Asunto(s)
Registros Electrónicos de Salud , Relaciones Médico-Paciente , Pautas de la Práctica en Medicina/estadística & datos numéricos , Atención Primaria de Salud/métodos , Adolescente , Adulto , Factores de Edad , Anciano , Comunicación , Computadores , Femenino , Humanos , Masculino , Persona de Mediana Edad , Médicos de Familia/estadística & datos numéricos , Adulto Joven
8.
Rev Clin Esp (Barc) ; 216(1): 15-8, 2016.
Artículo en Inglés, Español | MEDLINE | ID: mdl-26390835

RESUMEN

OBJECTIVE: The antibiotic treatment recommended for infectious endocarditis (IE) has a low level of evidence. Our objective was to determine whether compliance with the recommendations of the European Society of Cardiology (ESC) was related to lower inhospital morbidity and mortality for this disease. METHODS: A retrospective study was conducted on 162 cases of IE diagnosed between 2005 and 2014. A propensity score-matching analysis was performed to determine the effect of treatment on hospital mortality. RESULTS: There were no differences in terms of disease complications between the treatment groups. Hospital mortality was 29.2% when the treatment was adjusted to the guidelines and 28.2% when the treatment was not adjusted (OR=1.048; 95%CI: 0.442-2.484; P=.916). CONCLUSION: The use of the ESC guidelines does not appear to translate into a reduction in hospital morbidity and mortality due to IE when compared with alternative antibiotic treatment regimens.

9.
Adv Exp Med Biol ; 860: 301-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26303494

RESUMEN

Glutamate, released from central terminals of glossopharyngeal nerve, is a major excitatory neurotransmitter of commissural nucleus tractus solitarii (cNTS) afferent terminals, and brain derived neurotrophic factor (BDNF) has been shown to attenuate glutamatergic AMPA currents in NTS neurons. To test the hypothesis that AMPA contributes to glucose regulation in vivo modulating the hyperglycemic reflex with brain glucose retention (BGR), we microinjected AMPA and NBQX (AMPA antagonist) into the cNTS before carotid chemoreceptor stimulation in anesthetized normal Wistar rats, while hyperglycemic reflex an brain glucose retention (BGR) were analyzed. To investigate the underlying mechanisms, GluR2/3 receptor and c-Fos protein expressions in cNTS neurons were determined. We showed that AMPA in the cNTS before CChr stimulation inhibited BGR observed in aCSF group. In contrast, NBQX in similar conditions, did not modify the effects on glucose variables observed in aCSF control group. These experiments suggest that glutamatergic pathways, via AMPA receptors, in the cNTS may play a role in glucose homeostasis.


Asunto(s)
Encéfalo/metabolismo , Cuerpo Carotídeo/fisiología , Glucosa/metabolismo , Hipoxia/fisiopatología , Receptores de Glutamato/fisiología , Núcleo Solitario/fisiología , Animales , Masculino , Quinoxalinas/farmacología , Ratas , Ratas Wistar , Receptores AMPA/fisiología , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/farmacología
10.
J Chem Phys ; 143(6): 064504, 2015 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-26277142

RESUMEN

By means of Raman spectroscopy of liquid microjets, we have investigated the crystallization process of supercooled quantum liquid mixtures composed of parahydrogen (pH2) or orthodeuterium (oD2) diluted with small amounts of neon. We show that the introduction of the Ne impurities affects the crystallization kinetics in terms of a significant reduction of the measured pH2 and oD2 crystal growth rates, similarly to what found in our previous work on supercooled pH2-oD2 liquid mixtures [Kühnel et al., Phys. Rev. B 89, 180201(R) (2014)]. Our experimental results, in combination with path-integral simulations of the supercooled liquid mixtures, suggest in particular a correlation between the measured growth rates and the ratio of the effective particle sizes originating from quantum delocalization effects. We further show that the crystalline structure of the mixtures is also affected to a large extent by the presence of the Ne impurities, which likely initiate the freezing process through the formation of Ne-rich crystallites.

11.
J Chem Phys ; 141(11): 114301, 2014 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-25240352

RESUMEN

An explicit formulation of the rotational relaxation time in terms of state-to-state rate coefficients associated to inelastic collisions is reported. The state-to-state rates needed for the detailed interpretation of relaxation in H2 and D2, including isotopic variant mixtures, have been calculated by solving the close-coupling Schrödinger equations using the H2-H2 potential energy surface by Diep and Johnson [J. Chem. Phys. 112, 4465 (2000)]. Relaxation related quantities (rotational effective cross section, bulk viscosity, relaxation time, and collision number) calculated from first principles agree reasonably well with acoustic absorption experimental data on H2 and D2 between 30 and 293 K. This result confirms at once the proposed formulation, and the validation of the H2-H2 potential energy surface employed, since no approximations have been introduced in the dynamics. Accordingly, the state-to-state rates derived from Diep and Johnson potential energy surface appear to be overestimated by up to 10% for H2, and up to 30% for D2 at T = 300 K, showing a better agreement at lower temperatures.

12.
Disabil Rehabil Assist Technol ; 9(1): 3-11, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23597317

RESUMEN

PURPOSE: To assess the effectiveness of technical devices used in children with motor disabilities. METHOD: A systematic search of CINAHL Plus, EMBASE, PEDro, Cochrane Library, Isi Web of Knowledge and Scifinder Web was carried out, covering the period between January 2000 and January 2012. The inclusion criteria were: (1) Studies involving a minimum of five children (randomized-clinical trials with control group and experimental group, clinical trials without control group and prospective cohort studies; (2) age range, 0 to 18 years. The methodological quality of the included studies was assessed by the two authors through the application of the PEDro scale. RESULTS: Of the 59 articles identified by the search strategy, 27 articles were considered eligible. The most frequently evaluated devices were ankle and foot orthoses and the most studied pathology was cerebral palsy. The mean score on the PEDro scale was 6.8. CONCLUSIONS: The methodological quality of studies needs to be improved and more rigorous research designs should be followed that will allow the effectiveness and quality of movement to be assessed. The satisfaction of the patient and family with the devices should be analyzed in future studies.


Asunto(s)
Niños con Discapacidad/rehabilitación , Equipo Ortopédico , Proyectos de Investigación , Dispositivos de Autoayuda , Adolescente , Niño , Preescolar , Diseño de Equipo , Humanos , Lactante , Recién Nacido , Evaluación de Resultado en la Atención de Salud , Satisfacción del Paciente , Calidad de Vida
13.
Med Intensiva ; 36(7): 460-6, 2012 Oct.
Artículo en Español | MEDLINE | ID: mdl-22575389

RESUMEN

OBJECTIVE: To study the characteristics, evolution and prognosis of patients with infectious endocarditis requiring treatment in the Intensive Care Unit. DESIGN: A prospective, observational cohort study of patients admitted due to infectious endocarditis. SETTING: Nuestra Señora de Candelaria University Hospital, a third - level center with a recruitment population of 493,145. PATIENTS: All patients consecutively diagnosed with infectious endocarditis in our center according to the Duke criteria, between 1 January 2005 and 31 July 2011. STUDY VARIABLES: Demographic data, clinical severity scores, microbiological and echocardiographic data, hospital mortality and complications. RESULTS: Out of 102 patients diagnosed with endocarditis, 38 (37%) were admitted to Intensive Care. Compared with those patients not admitted to the ICU, these subjects suffered more frequent mitral valve alterations (OR= 7.13; 95%CI: 2.12-24; p= 0.002) and cerebral embolism (OR= 3.89; 95%CI: 1.06-14.3; p= 0.041). In turn, mortality was greater (42.1% vs 18.8%, p= 0.011), as was the proportion of emergency surgeries (45.8% vs 5.9%, p<0.001). The identified mortality predictors were Staphylococcus aureus infection (OR= 3.49; 95%CI 1.02-11.93; p=0.046), heart failure (OR=4.18; 95%CI: 1.17-14.94; p=0.028), cerebral embolism (OR= 8.45; 95%CI: 1.89-37.74; p=0.005) and the SAPS II upon admission (OR=1.09; 95%CI: 1.04-1.15; p<0.001). CONCLUSIONS: A large proportion of patients with endocarditis require admission to the Intensive Care Unit, presenting a much poorer prognosis. Staphylococcus aureus infection, heart failure, cerebral embolism and SAPS II scores are independent predictors of hospital mortality.


Asunto(s)
Endocarditis Bacteriana , Unidades de Cuidados Intensivos , Estudios de Cohortes , Endocarditis Bacteriana/diagnóstico , Endocarditis Bacteriana/mortalidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos
14.
J Chem Phys ; 134(17): 174307, 2011 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-21548687

RESUMEN

Close-coupling calculations and experiment are combined in this work, which is aimed at establishing a set of state-to-state rate coefficients for elementary processes ij → lm in O(2):O(2) collisions at low temperature involving the rotational states i, j, l, m of the vibrational ground state of (16)O(2)((3)Σ(g)(-)). First, a set of cross sections for inelastic collisions is calculated as a function of the collision energy at the converged close-coupled level via the MOLSCAT code, using a recent ab-initio potential energy surface for O(2)-O(2) [M. Bartolomei et al., J. Chem. Phys. 133, 124311 (2010)]. Then, the corresponding rates for the temperature range 4 ≤ T ≤ 34 K are derived from the cross sections. The link between theory and experiment is a Master Equation which accounts for the time evolution of rotational populations in a reference volume of gas in terms of the collision rates. This Master Equation provides a linear function of the rates for each rotational state and temperature. In the experiment, the evolution of rotational populations is measured by Raman spectroscopy in a tiny reference volume (≈2 × 10(-4) mm(3)) of O(2) travelling along the axis of a supersonic jet at a velocity of ≈700 m/s. The accuracy of the calculated rates is assessed experimentally for 10 ≤ T ≤ 34 K by means of the Master Equation. The rates, jointly with their confidence interval estimated by Monte Carlo simulation, account to within the experimental uncertainty for the evolution of the populations of the N = 1, 3, 5, 7 rotational triads along the supersonic jet. Confidence intervals range from ≈6% for the dominant rates at 34 K, up to ≈17% at 10 K. These results provide an experimental validation of state-to-state rates for O(2):O(2) inelastic collisions calculated in the close-coupling approach and, indirectly, of the anisotropy of the O(2)-O(2) intermolecular potential employed in the calculation for energies up to 300 cm(-1).

15.
Phys Chem Chem Phys ; 12(38): 12060-4, 2010 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-20683514

RESUMEN

The very first steps of condensation as studied experimentally in the simplest molecular system (para-H(2)) are reported. The fast time-space evolution of the nascent clusters have been measured using state-of-the-art Raman spectroscopy implemented on cryogenic supersonic jets. The time-dependent onset of condensation is presented in a non-equilibrium pressure-temperature phase diagram. Dimer and trimer formation are found to obey three-body processes whose rates have been determined.

16.
J Phys Chem A ; 114(29): 7761-8, 2010 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-20593875

RESUMEN

We report an experimental study of the shock wave system of three continuous axisymmetric jets of pure N(2) and H(2), and of the N(2) + 2H(2) mixture, generated at p(0) = 1 bar and T(0) = 295 K through a D = 310 microm cylindrical nozzle against a background pressure p(b) = 6.1 mbar. Number density and rotational populations have been measured by Raman spectroscopy with high spatial resolution (approximately 15 microm) across the normal shock wave located at z/D approximately 8, and across the barrel shock wave at the plane z/D = 5.2. Significant differences in position, widths, and gradients of the shock waves are observed among the three jets. Such differences are qualitatively interpreted in terms of disparity in mass, inelastic cross sections, and collision numbers. Non-Boltzmann distributions of the rotational populations of N(2) are observed within the shock waves at regions where the local Knudsen number is higher than 0.05. In the N(2) + 2H(2) mixture the different behavior of the two species leads to a localized enrichment of the light component up to 20%, which might provide the basis for an efficient separation device. Measurements on the invasion of the shock wave system by the background molecules are also reported, proving such invasion to be more efficient for the lighter species H(2) than for the heavier N(2).

17.
Nitric Oxide ; 22(4): 296-303, 2010 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-20156578

RESUMEN

Neuronal nitric oxide synthase (nNOS), which catalyzes the generation of nitric oxide (NO), is expressed by neuron subpopulations in the CNS. Nitric oxide is involved in neurotransmission and central glucose homeostasis. Our prior studies have shown that carotid body receptors participate in brain glucose regulation in vivo, and suggest the presence of a NO tonic mechanism in the solitary tract nucleus (STn). However, the role of NO within STn in glucose control remains unknown. In this study, we explored the potential regulatory role of NO on brain glucose retention induced by carotid body chemoreceptor anoxic stimulation with sodium cyanide (NaCN) which inhibits oxidative metabolism. Intracisternal infusions of nitroxidergic drugs before carotid chemoreceptor stimulation in anesthetized rats, elicited changes in nitrite concentration in plasma and hypothalamus-pituitary (H-P) tissue, as well as in gene expression of neuronal and inducible isoforms (nNOS and iNOS) in H-P tissue. The changes observed in above variables modified brain glucose retention in an opposite direction. When the NO donor, sodium nitroprusside (SNP), was given before carotid stimulation, nitrite concentration in plasma and H-P tissue, and gene expression of nNOS and iNOS in H-P tissue increased, whereas brain glucose retention decreased. In contrast, when the NOS inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME) was infused immediately before carotid chemoreceptor stimulation, nitrite levels and nNOS expression decreased in plasma and H-P tissue, whereas brain glucose retention increased. Anoxic stimulation by itself induced an increase in the expression of both genes studied. All these results indicate that de novo expression of the nNOS gene in H-P tissue may be critically involved in central glucose changes observed after anoxic carotid chemoreceptor stimulation in conjunction with NO.


Asunto(s)
Encéfalo/metabolismo , Células Quimiorreceptoras/metabolismo , Inhibidores Enzimáticos/farmacología , Glucosa/metabolismo , Sistema Hipotálamo-Hipofisario/metabolismo , Óxido Nítrico/metabolismo , Cianuro de Sodio/farmacología , Animales , Cuerpo Carotídeo/metabolismo , Hipotálamo/metabolismo , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/genética , Óxido Nítrico Sintasa de Tipo I/metabolismo , Hipófisis/metabolismo , Ratas
18.
J Phys Chem A ; 113(30): 8506-12, 2009 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-19719308

RESUMEN

Number density and rotational temperature in the zone of silence of supersonic jets of N(2), H(2), and their mixtures N(2) + 2H(2) and 2N(2) + H(2), at p(0) = 1 bar and T(0) = 295 K, have been measured by Raman spectroscopy. Translational temperature in the jets has been derived from the experimental data assuming isentropic flow. The density along the jet axis decays at a rate depending on the composition of the expanded gas, which can be explained by the variation of its effective heat capacity ratio. Measurements across the jet axis do not support numerical off-axis density modeling from the literature. A strong nonequilibrium between the rotational degrees of freedom of both species is observed, even between the two spin species ortho-H(2) and para-H(2). From the corresponding rotational temperature data, a relationship between rotational cross sections for the inelastic collisions of the different species is established. In the expansions of the mixtures, an enrichment of N(2) is measured on the axis, which is compared with the predictions from the theory of diffusive separation in jets.

19.
Adv Exp Med Biol ; 648: 403-10, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19536505

RESUMEN

We evaluate in rats the role of NO in the solitary tract nucleus (STn) after an anoxic stimulus to carotid body chemoreceptor cells (CChrc) with cyanide (NaCN), on the hyperglycemic reflex with glucose retention by the brain (BGR) and FOS expression (FOS-ir) in the STn. The results suggest that nitroxidergic pathways in the STn may play an important role in glucose homeostasis. A NO donor such as sodium nitroprusside (NPS) in the STn before CChrc stimulation increased arterial glucose level and significantly decreased BGR. NPS also induced a higher FOS-ir expression in STn neurons when compared to neurons in control rats that only received artificial cerebrospinal fluid (aCSF) before CChrc stimulation. In contrast, a selective NOS inhibitor such as Nomega-nitro-L-arginine methyl ester (L-NAME) in the STn before CChrc stimulation resulted in an increase of both, systemic glucose and BGR above control values. In this case, the number of FOS-ir positive neurons in the STn decreased when compared to control or to NPS experiments. FOS-ir expression in brainstem cells suggests that CChrc stimulation activates nitroxidergic pathways in the STn to regulate peripheral and central glucose homeostasis. The study of these functionally defined cells will be important to understand brain glucose homeostasis.


Asunto(s)
Cuerpo Carotídeo/metabolismo , Regulación de la Expresión Génica , Glucosa/metabolismo , Homeostasis , Óxido Nítrico/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Núcleo Solitario/metabolismo , Animales , Cuerpo Carotídeo/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Homeostasis/efectos de los fármacos , Masculino , Neuronas/metabolismo , Nitroprusiato/farmacología , Fotomicrografía , Ratas , Ratas Wistar , Cianuro de Sodio/farmacología , Núcleo Solitario/efectos de los fármacos , Factores de Tiempo
20.
J Chem Phys ; 128(22): 224308, 2008 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-18554014

RESUMEN

Inelastic H(2):He collisions are studied from the experimental and theoretical points of view between 22 and 180 K. State-to-state cross sections and rates are calculated at the converged close-coupling level employing recent potential energy surfaces (PES): The MR-PES [J. Chem. Phys. 100, 4336 (1994)], and the MMR-PES and BMP-PESs [J. Chem. Phys. 119, 3187 (2003)]. The fundamental rates k(2-->0) and k(3-->1) for H(2):He collisions are assessed experimentally on the basis of a master equation describing the time evolution of rotational populations of H(2) in the vibrational ground state. These populations are measured in the paraxial region of supersonic jets of H(2)+He mixtures by means of high-sensitivity and high spatial resolution Raman spectroscopy. Good agreement between theory and experiment is found for the k(2-->0) rate derived from the MR-PES, but not for the BMP-PES. For the k(3-->1) rate, which is about one-third to one-half of k(2-->0), the result is less conclusive. The experimental k(3-->1) rate is compatible within experimental error with the values calculated from both PESs. In spite of this uncertainty, the global consistence of experiment and theory in the framework of Boltzmann equation supports the MR-PES and MMR-PESs, and the set of gas-dynamic equations employed to describe the paraxial region of the jet at a molecular level.

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