427 results on '"Miguel A. Valverde"'
Search Results
352. Inactivation of the murine cftr gene abolishes cAMP-mediated but not Ca(2+)-mediated secretagogue-induced volume decrease in small-intestinal crypts
- Author
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Martin J. Evans, Francisco V. Sepúlveda, John A. O'Brien, Miguel A. Valverde, Rosemary Ratcliff, and William H. Colledge
- Subjects
medicine.medical_specialty ,Carbachol ,Cystic Fibrosis ,Physiology ,Clinical Biochemistry ,Vasoactive intestinal peptide ,Crypt ,chemistry.chemical_element ,Cystic Fibrosis Transmembrane Conductance Regulator ,Calcium ,4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid ,chemistry.chemical_compound ,Mice ,Chloride Channels ,Physiology (medical) ,Internal medicine ,Glyburide ,Intestine, Small ,medicine ,Cyclic AMP ,Animals ,biology ,Electric Conductivity ,Membrane Proteins ,Molecular biology ,digestive system diseases ,Cystic fibrosis transmembrane conductance regulator ,Endocrinology ,chemistry ,Gene Expression Regulation ,DIDS ,biology.protein ,Chloride channel ,Secretagogue ,medicine.drug ,Vasoactive Intestinal Peptide - Abstract
The cellular volume of crypts isolated from 2- to 3-week-old mouse small intestine has been measured to assess the capacity of the epithelial cells to respond to secretagogues. Vasoactive intestinal polypeptide (VIP) or carbachol, respectively cAMP- and calcium-mediated secretagogues, produced a reduction crypt volume attributed to KCl loss through channels activated by the agonists. Consistent with the participation of separate chloride channels, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) blocked the carbachol- but not the VIP-induced volume decrease, whilst glibenclamide abolished the VIP effect without affecting the carbachol-induced volume decrease. Animals homozygous for a disrupted cftr gene, introduced by gene targeting, were also used as the source for crypt isolation. In these CFTR (-/-) crypts. VIP failed to elicit any reduction in cellular volume, while the response to carbachol was indistinguishable from that seen in crypts from age-matched control animals. These results are consistent with murine CFTR being a cAMP-activated chloride channel inhibited by glibenclamide and resistant to DIDS. A separate chloride conductance activated by calcium mobilization in small-intestinal crypts appears to be independent of CFTR.
- Published
- 1993
353. GLOBAL AND SEASONAL-VARIATIONS IN MIDDLE ATMOSPHERE CO FROM UARS ISAMS
- Author
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Manuel López-Puertas, C. J. Marks, Miguel Lopez-Valverde, and Fredric W. Taylor
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Atmosphere ,Atmospheric sounding ,Geophysics ,Atmosphere of Earth ,Abundance (ecology) ,Radiance ,General Earth and Planetary Sciences ,Polar ,Environmental science ,Satellite ,Atmospheric sciences ,Stratosphere - Abstract
Carbon monoxide limb emissions at 4.6-μm measured by the Improved Stratospheric And Mesospheric Sounder (ISAMS) on board the Upper Atmosphere Research Satellite (UARS) are presented. The main features observed in the radiance measurements are presented and discussed. These radiances are used to obtain the CO abundances in the middle atmosphere, using a special retrieval scheme which incorporates the non-LTE nature of the CO emission at 4.6-μm. The first global maps of the CO abundance in the middle atmosphere illustrating its latitudinal/seasonal variations are presented and briefly discussed. One of the most interesting results obtained is the increase in the CO relative abundance in the mesosphere towards the winter polar region, in accordance with previous predictions by 2D dynamical-chemical models of the middle atmosphere.
- Published
- 1993
354. Regulatory volume increase after hypertonicity- or vasoactive-intestinal-peptide-induced cell-volume decrease in small-intestinal crypts is dependent on Na(+)-K(+)-2Cl- cotransport
- Author
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Miguel A. Valverde, R. J. Walters, John A. O'Brien, and Francisco V. Sepúlveda
- Subjects
Male ,medicine.medical_specialty ,Physiology ,Enterocyte ,Sodium-Potassium-Chloride Symporters ,Clinical Biochemistry ,Vasoactive intestinal peptide ,Guinea Pigs ,Hypertonic Solutions ,Sodium Chloride ,Potassium Chloride ,Physiology (medical) ,Internal medicine ,Intestine, Small ,medicine ,Animals ,Mannitol ,Bumetanide ,Osmotic concentration ,Chemistry ,Osmolar Concentration ,Biological Transport ,Hypertonic Shock ,Amiloride ,Kinetics ,Endocrinology ,medicine.anatomical_structure ,Tonicity ,Secretagogue ,Carrier Proteins ,medicine.drug ,Vasoactive Intestinal Peptide - Abstract
The volume of intact crypts isolated from guinea-pig small intestine has been measured to assess the capacity of the cells to regulate their volume after hypertonic shock or vasoactive-intestinal-peptide (VIP)-induced shrinkage. Crypts exposed to anisotonic medium initially behave as perfect osmometers. Continued exposure to a hypertonic (400 mosmol/l) medium was followed by regulatory volume increase (RVI), which led to complete volume recovery in about 20 min. VIP produced a volume reduction, attributed to KCl loss through channels activated by the secretagogue, without any recovery during exposure to the polypeptide. Removal of VIP led to an increase of cellular volume towards control levels. This volume recovery after secretagogue-induced shrinkage is termed SVI. Both RVI and SVI were abolished by removal of Na+ or Cl- from the bathing solution, by addition of the loop diuretic bumetanide (1 microM), but not by addition of ethylisopropylamiloride (10 microM) or amiloride (1 mM). Cell shrinkage was also observed when tonicity was increased by addition of 100 mM NaCl or 200 mM D-mannitol, but RVI was seen only when NaCl was the added osmolyte. The ion dependence, pharmacological sensitivity and thermodynamic considerations of these effects are consistent with the operation of a Na(+)-K(+)-2Cl- cotransport mechanism activated by cell shrinkage and the secretagogue action of VIP.
- Published
- 1993
355. Volume-activated chloride channels in HeLa cells are blocked by verapamil and dideoxyforskolin
- Author
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C. Rucăreanu, Mario Díaz, Miguel A. Valverde, Francisco V. Sepúlveda, and Christopher F. Higgins
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Osmosis ,Physiology ,Stereochemistry ,Clinical Biochemistry ,Chloride ,Ion Channels ,Membrane Potentials ,HeLa ,Adenosine Triphosphate ,Chlorides ,Chloride Channels ,Physiology (medical) ,Extracellular ,medicine ,Humans ,P-glycoprotein ,biology ,Chemistry ,Colforsin ,Membrane Proteins ,Membrane transport ,biology.organism_classification ,Hypotonic Solutions ,Verapamil ,Chloride channel ,biology.protein ,Biophysics ,Intracellular ,medicine.drug ,HeLa Cells - Abstract
The possible role of Cl- currents in regulatory volume decrease processes has been explored in HeLa cells using the whole-cell recording mode of the patch-clamp technique. Cells showed very small currents in voltage-clamp experiments performed with Cl(-)-rich, permeant-cation-free (N-methyl-D-glucamine replacement) intracellular and bathing solutions. Exposure of the cells to hypotonic solutions visibly swelled the cells and activated, reversibly, an outward rectifying Cl- current, which decayed at the most depolarised voltages used. Replacement of extracellular Cl- by a series of halide anions, SCN- and gluconate was consistent with an anion selectivity sequence: SCN-I-Br-Cl-F-gluconate. The volume-regulated Cl- current was effectively inhibited by 100 microM 5-nitro-2-(3-phenyl-propylamino)-benzoic acid and by 100 microM 4,4'-diisothiocyanotostilbene-2,2-disulphonic acid, substances known to block Cl- channels in a variety of cells. Chloride current activation by hypotonicity was dependent on the presence of ATP in the intracellular solution and this requirement could be replaced by the non-hydrolysable analogue ATP[gamma S] and Mg(2+)-free ATP. The data suggest that the channels responsible for the current described are involved in the regulatory volume decrease in HeLa cells. The characteristics of this Cl- current are similar to those of the current associated with expression of multidrug resistance P-glycoprotein. Furthermore, the currents in HeLa cells were inhibited rapidly and reversibly by verapamil and 1,9-dideoxyforskolin, which are known to inhibit P-glycoprotein function.
- Published
- 1993
356. Development of Na(+)- and K(+)-currents in the cochlear ganglion of the chick embryo
- Author
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D.N. Sheppard, F. Giraldez, J. Represa, and Miguel A. Valverde
- Subjects
Potassium Channels ,Chick Embryo ,Tetrodotoxin ,Biology ,Sodium Channels ,Membrane Potentials ,chemistry.chemical_compound ,Extracellular ,medicine ,Animals ,Inner ear ,Patch clamp ,Spiral ganglion ,Neurons ,Tetraethylammonium ,General Neuroscience ,Anatomy ,Immunohistochemistry ,Ganglion ,Cochlea ,Electrophysiology ,medicine.anatomical_structure ,chemistry ,Biophysics ,Ganglia - Abstract
The development of Na + - and K + -currents in the primary afferent neurons of the cochlear ganglion was studied using the patch-clamp technique. Cells were dissociated between days 6 and 17 of development and membrane currents recorded within the following 24 h. Outward currents were the first to appear between days 6 and 7 of embryonic development and their magnitude increased throughout development from 200 pA on day 7 to 900 pA on days 14–16. Threshold for activation decreased by 20 mV between days 8 and 14. Outward currents were absent when Cs + replaced K + in the pipette and were partially blocked by external tetraethylammonium. Outward currents contained at least three components: (i) a non-inactivating outward current, similar to the delayed-rectifier, predominating in mature neurons: (ii) a slowly inactivating current (tau about 200 ms), most evident in early and intermediate stages (days 7–10); and (iii) a rapidly inactivating outward current (tau about 20ms) similar to the A-current ( I A ) described in other neurons, which was distinctly expressed in mature neurons. Sodium currents were identified as fast transient inward currents, sensitive to tetrodotoxin and extracellular Na + -removal. They appeared later than K + -currents and increased in size from about 100 pA between days 9–11 to 600 pA by days 13–16. The development of membrane currents in cochlear ganglion neurons corresponded to defined stages of the innervation pattern of the chick cochlea [ Whitehead and Morest (1985) Neuroscience 14 , 255–276]. These currents could be functionally related to the establishment of synaptic connections between transducing cells and primary afferent neurons.
- Published
- 1992
357. Separation of drug transport and chloride channel functions of the human multidrug resistance P-glycoprotein
- Author
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Stephen C. Hyde, G. M. Mintenig, Francisco V. Sepúlveda, Christopher F. Higgins, Deborah R. Gill, and Miguel A. Valverde
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Drug Resistance ,Biological Transport, Active ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Ion Channels ,Adenosine Triphosphate ,Chlorides ,ATP hydrolysis ,Chloride Channels ,Tumor Cells, Cultured ,Cytotoxic T cell ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,P-glycoprotein ,Membrane Glycoproteins ,Membrane Proteins ,Membrane transport ,Multiple drug resistance ,Biochemistry ,Mutagenesis ,Vincristine ,Chloride channel ,Biophysics ,biology.protein ,Tonicity ,Function (biology) - Abstract
The human multidrug resistance P-glycoprotein is an active transporter that pumps cytotoxic drugs out of cells. Expression of P-glycoprotein is also associated with a volume-activated chloride channel. Here we address the relationship between these two functions. Drug transport requires ATP hydrolysis while, in contrast, ATP binding is sufficient to enable activation of the chloride channel. The chloride channel and drug transport activities of P-glycoprotein appear to reflect two distinct functional states of the protein that can be interconverted by changes in tonicity. Transportable drugs prevent channel activation but have no effect on channel activity once it has been preactivated by hypotonicity. The transport and channel functions of P-glycoprotein have been separated by directed mutations in the nucleotide-binding domains of the protein. These data provide further evidence that P-glycoprotein is bifunctional with both transport and channel activities. Implications for the design of chemotherapeutic drugs and for the function of the related cystic fibrosis gene product, CFTR, are discussed.
- Published
- 1992
358. LOCAL THERMODYNAMIC-EQUILIBRIUM OF CARBON-DIOXIDE IN THE UPPER-ATMOSPHERE
- Author
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Manuel López-Puertas, Fredric W. Taylor, Miguel Lopez-Valverde, Clive D. Rodgers, and Ann Muggeridge
- Subjects
Atmosphere ,Physics ,Geophysics ,Atmospheric models ,Radiative cooling ,Thermodynamic equilibrium ,General Earth and Planetary Sciences ,Rotational temperature ,Atomic physics ,Thermosphere ,Atmospheric sciences ,Vibrational temperature ,Mesosphere - Abstract
The rotational and vibrational temperatures of the v2 and 2v2 modes of carbon dioxide in the upper atmosphere have been derived from transmission spectra measured by the ATMOS instrument on Spacelab 3 over the height range 60–110 km. The rotational and vibrational temperature profiles are found to be nearly identical, which leads to the conclusion that the CO2 (v2) level is in local thermodynamic equilibrium (LTE) within the experimental errors up to 95 km, and very nearly so to at least 110 km. The CO2 (2v2) level is found to be close to LTE up to at least the upper height limit of its retrieval, i.e., 93 km. The interpretation of those measurements using a non-LTE model [Lopez-Puertas et al., 1986] supports a fast rate for the deactivation of CO2(v2) by atomic oxygen, similar to that derived by Sharma and Wintersteiner [1990]. This provides independent confirmation, from a qualitatively different type of measurement, of the conclusion of those authors that the radiative cooling of the upper atmospheres of the Earth is around an order of magnitude greater than our 1986 model predicted. It also has implications for thermospheric cooling on the other terrestrial planets, as well as expanding the possibilities for future remote sensing of the temperature of the upper mesosphere and lower thermosphere, since the upper limit which can be sounded is higher than previously believed.
- Published
- 1992
359. Human TRPV4 channel splice variants revealed a key role of ankyrin domains in multimerization and trafficking. VOLUME 281 (2006) PAGES 1580-1586
- Author
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Nadine Albrecht, Maite Arniges, Miguel A. Valverde, Michael Schaefer, and José M. Fernández-Fernández
- Subjects
Genetics ,chemistry.chemical_classification ,Trpv4 channel ,chemistry ,Key (cryptography) ,Ankyrin ,splice ,Cell Biology ,Computational biology ,Biology ,Molecular Biology ,Biochemistry ,Volume (compression) - Published
- 2006
360. We-P11:172 Haplotypes of the KCNMB1 potassium channel subunit as genetic markers for hypertension and response to antihypertensive therapy
- Author
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Miguel A. Valverde, Jaume Marrugat, J.M. Fernández-Fernández, Marta Tomás, and Mariano Sentí
- Subjects
Genetic marker ,Protein subunit ,Haplotype ,Internal Medicine ,General Medicine ,Pharmacology ,Biology ,Cardiology and Cardiovascular Medicine ,Potassium channel - Published
- 2006
361. We-P11:171 Haplotypes in the KCNMA1 potassium channel alpha-subunit gene as risk factors for human essential hypertension
- Author
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Miguel A. Valverde, Esther Vázquez, Jaume Marrugat, Roberto Elosua, Isaac Subirana, Mariano Sentí, Cristina Plata, G. Latorre, M. Fernandez-Fernandez, and Marta Tomás
- Subjects
Genetics ,Haplotype ,Internal Medicine ,medicine ,General Medicine ,Biology ,Cardiology and Cardiovascular Medicine ,Essential hypertension ,medicine.disease ,Gene ,Potassium channel ,G alpha subunit - Published
- 2006
362. Acute abdomen from duodenal diverticulitis: a case report
- Author
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Antonio José Fernández-López, Miguel González-Valverde, Nuria Martínez-Sanz, María Encarnación Tamayo-Rodríguez, and Antonio Albarracín-Marín-Blázquez
- Subjects
Diseases of the digestive system. Gastroenterology ,RC799-869
363. Association Analysis Between Hypertension and CYBA, CLCNKB, and KCNMB1 Functional Polymorphisms in the Japanese Population: The Suita Study
- Author
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Miguel A. Valverde
- Subjects
Genetics ,CLCNKB ,biology ,business.industry ,biology.protein ,Medicine ,General Medicine ,Japanese population ,Cardiology and Cardiovascular Medicine ,business ,Genetic association - Published
- 2005
364. Lens opacification by antioestrogens: tamoxifen vs ICI 182, 780
- Author
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Jin Jun Zhang, Timothy John Claud Jacob, Simon P. Hardy, Miguel A. Valverde, and Christopher F. Higgins
- Subjects
medicine.medical_specialty ,Patch-Clamp Techniques ,In Vitro Techniques ,Biology ,Cataract ,Neuroblastoma ,Chloride Channels ,Internal medicine ,Tumor Cells, Cultured ,medicine ,Cultured cell ,Animals ,Patch clamp ,Fulvestrant ,Pharmacology ,Estradiol ,Estrogen Antagonists ,Antiestrogen ,In vitro ,Disease Models, Animal ,Tamoxifen ,Endocrinology ,Mechanism of action ,Toxicity ,Chloride channel ,Cattle ,medicine.symptom ,hormones, hormone substitutes, and hormone antagonists ,Research Article ,medicine.drug - Abstract
The antioestrogen, tamoxifen, blocks volume-regulated chloride channels and reduces transparency in bovine lenses maintained in vitro. In contrast to tamoxifen, the steroidal antioestrogen, ICI 182780, did not block volume-regulated chloride currents in three cultured cell lines and required 10 fold higher concentration to induce significant opacification of bovine lenses maintained in vitro. These data suggest that ocular toxic side effects will be minimized by use of the steroidal (ICI 182780) rather than nonsteroidal antioestrogens (tamoxifen).
- Published
- 1995
365. Latrodectismo mortal en un anciano
- Author
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Francisco Menarguez Pina, José Luis Vázquez Rojas, Francisco Miguel González Valverde, and María Jesús Gómez Ramos
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business.industry ,Medicine ,General Medicine ,business ,Humanities - Published
- 2001
366. A non-local thermodynamic equilibrium radiative transfer model for infrared emissions in the atmosphere of Mars: 2. Daytime populations of vibrational levels
- Author
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Manuel López-Puertas and Miguel Lopez-Valverde
- Subjects
Physics ,Atmospheric Science ,Daytime ,education.field_of_study ,Ecology ,Thermodynamic equilibrium ,Population ,Paleontology ,Soil Science ,Forestry ,Aquatic Science ,Oceanography ,Mesosphere ,Geophysics ,Atmospheric radiative transfer codes ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Radiative transfer ,Atomic physics ,Thermosphere ,education ,Vibrational temperature ,Earth-Surface Processes ,Water Science and Technology - Abstract
A non-local thermodynamic equilibrium (LTE) radiative transfer model has been applied to study the CO2 and CO emissions in the infrared (1–20 μm) in the atmosphere of Mars during daytime conditions. An extensive set of vibrational-translational (V-T) and vibrational-vibrational (V-V) collisional exchanges among the vibrational levels responsible for these emissions has been considered. Radiative transfer has been included for most of the transitions and its importance illustrated for some of them. The populations of the most important vibrational levels of GO and of the ν2 and ν3 modes of CO2 are presented. The CO2(0,ν2,0) levels follow LTE up to about 80 km at daytime, some 5 km lower than at nighttime conditions. The absorption of solar radiation at 1.6, 2.0, and 2.7 μm, and subsequent relaxation by V-V and radiative processes, significantly populates these levels in the lower thermosphere, increasing all their vibrational temperatures with respect to nighttime conditions. Solar excitation and radiative transfer in 4.3 μm constitute the main sources of excitation of the (0,0°,1) level in the thermosphere, where this level shows a very large vibrational temperature. The V-V transfer from highly excited CO2 levels is even larger than the direct radiative excitation of the (0,0°,1) level in the mesosphere. The model predicts that the known inversion population between this vibrational level and the lower (0,2°,0) and (1,0°,0) levels will occur in the high mesosphere and above. The CO(1) level also shows much larger populations than during nighttime conditions, due to direct solar absorption at 4.7 μm and the role played by radiative transfer. A sensitivity study of the effect of current uncertainties in rate constants on the level populations is also presented. The uncertainties in the rate for ν3 quanta exchange among CO2 levels have significant effects on the deactivation of high energy states, leading to changes of importance in the daytime populations of the 2.7-μm states in the mesosphere and in the (0,0°,1) level in the lower thermosphere.
- Published
- 1994
367. Non-local thermodynamic equilibrium studies of the 15-μm bands of CO2for atmospheric remote sensing
- Author
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Manuel López-Puertas, David P. Edwards, and Miguel Lopez-Valverde
- Subjects
Atmospheric sounding ,Physics ,Atmospheric Science ,Ecology ,Mean kinetic temperature ,Atmospheric models ,Thermodynamic equilibrium ,Paleontology ,Soil Science ,Tangent ,Forestry ,Aquatic Science ,Oceanography ,Spectral line ,Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Radiance ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,Physics::Atmospheric and Oceanic Physics ,Earth-Surface Processes ,Water Science and Technology ,Remote sensing - Abstract
A new line-by-line non-local thermodynamic equilibrium (non-LTE) radiance model based on the GENLN2 radiative transfer code is presented. This is capable of high resolution spectral radiance calculations for the upper atmosphere. We describe the non-LTE model implementation and discuss the molecular state vibrational temperature input requirements for studies of the 15-μm ν2 bands of CO2. Monochromatic and band-integrated radiance calculations have been performed for atmospheric limb view tangent heights between 50 and 120 km for non-LTE nighttime and daytime conditions. Two model atmospheres are considered, the U.S. 1976 Standard and a subarctic summer, which show, respectively, mean and large radiance differences from a reference LTE radiance calculation. Non-LTE radiance considerations are shown to be important for the 15-μm CO2 bands for tangent heights greater than 70 km, the magnitude of the divergence from LTE values and diurnal variation being dependent on the band and kinetic temperature profile. We show that the use of the Voigt line shape, rather than the Doppler, is important for tangent heights below 85 km, and that the inclusion of the effect of overlapping lines is a consideration for tangent heights below 75 km. We present calculations of synthetic radiance spectra showing the non-LTE effect for two CO2 temperature sounding channels of instruments aboard the Upper Atmosphere Research Satellite as a demonstration of the model capability.
- Published
- 1993
368. Analysis of the upper atmosphere CO2(v2) vibrational temperatures retrieved from ATMOS/Spacelab 3 observations
- Author
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Curtis P. Rinsland, M. R. Gunson, Manuel López-Puertas, and Miguel Lopez-Valverde
- Subjects
Atmospheric Science ,Materials science ,Mean kinetic temperature ,Soil Science ,Aquatic Science ,Oceanography ,Atmospheric sciences ,Mesosphere ,Atmospheric radiative transfer codes ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Radiative transfer ,Physics::Atmospheric and Oceanic Physics ,Vibrational temperature ,Earth-Surface Processes ,Water Science and Technology ,Ecology ,Atmospheric models ,Paleontology ,Forestry ,Atmospheric temperature ,Geophysics ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Thermosphere ,Atomic physics - Abstract
An analysis of the upper atmospheric (80-116 km) CO2(nu-2) vibrational temperatures retrieved from atmospheric trace molecule spectroscopy (ATMOS) experiment Spacelab 3 spectra by using a nonlocal thermodynamic equilibrium (non-LTE) radiative transfer model is presented. Thermal collisions with atmospheric atomic oxygen keep this vibrational state very close to LTE up to around 100 km. Above this height, the different deviations from LTE retrieved from ATMOS/Spacelab 3 spectra for the Northern and the Southern Hemispheres are explained in terms of this collisional process and in terms of the different kinetic temperature profiles measured at those locations. From these simultaneous observations of the kinetic and CO2(nu-2) vibrational temperatures, a deactivation rate of CO2(nu-2) by O(3P) has been derived which leads to a rate coefficient value between 3 and 6 x 10 exp -12 cu cm/s and favors an independent or negative temperature dependence rate constant for the atmospheric temperature range. Cooling rates induced by the CO2 15-micron fundamental band in the upper mesosphere and lower thermosphere were derived from the simultaneous kinetic temperature, CO2(nu-2) vibrational temperature, and CO2 concentration, as measured by ATMOS/Spacelab 3, and found to be a factor of between 5 and 10 times larger than those generally accepted until very recently.
- Published
- 1992
369. The U. S. and Mexico: Borderland Development and the National Economies James Gibson Alfonso Corona Rentería
- Author
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Loya, Miguel Ángel Valverde
- Published
- 1987
370. Hypotonicity increases apical membrane Cl− conductance in Necturus enterocytes
- Author
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Francisco V. Sepúlveda, Miguel A. Valverde, and F. Giraldez
- Subjects
Membrane potential ,medicine.medical_specialty ,biology ,Enterocyte ,Chemistry ,Biophysics ,Conductance ,Cell Biology ,Apical membrane ,Membrane transport ,biology.organism_classification ,Biochemistry ,Endocrinology ,Necturus ,medicine.anatomical_structure ,Internal medicine ,medicine ,Ion transporter ,Intracellular - Abstract
The effects of hypotonicity on epithelial cells of Necturus small intestine has been studied using conventional and Cl−-selective microelectrodes. Exposure to a mucosal solution made hypoosmotic by 70 mosmolal provokes a rapid dilution of intracellular Cl−, consistent with a perfect osmometer behaviour of the cell. The swollen cells showed an increased apical membrane Cl− conductance. The increased Cl− conductance might be involved in regulatory volume decrease.
- Published
- 1988
371. Behaviour of the O2 infrared atmospheric (0-0) band in the middle atmosphere during evening twilight and at night
- Author
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Miguel Lopez-Valverde, M. J. López-González, J. J. Lopez-Moreno, and R. Rodrigo
- Subjects
Daytime ,Twilight ,Ozone ,Infrared ,Airglow ,Astronomy and Astrophysics ,Sunset ,Atmospheric sciences ,Atmosphere ,chemistry.chemical_compound ,chemistry ,Space and Planetary Science ,Atmospheric chemistry ,Environmental science - Abstract
Measurements of the 0-0 band of the Infrared Atmospheric System of the molecular oxygen during early night-time show a non-negligible fraction of the emission which is a remnant of the very high concentration of atmospheric O 2 ( a 1 Δ g ) during the day. The importance of this contribution decreases progressively after sunset. The complexity of the photochemistry during twilight, involving fast variation in the concentration of the atmospheric compounds and in the solar fluxes, makes it difficult to study the decay of the daytime emission. We have developed a detailed treatment of the different processes governing the production and loss mechanisms of the O 2 ( a 1 Δ g ) at times near sunset and during the night. This model is capable of explaining the remnant observed in measurements carried out by rocket-borne instrumentation.
- Published
- 1989
372. Gangrena gaseosa de la mama
- Author
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José Luis Lobato Miguélez, Cristóbal Franquelo Wierhan, Alfredo Calleja Perales, Tamara Dehesa Martínez, and Miguel López Valverde
- Subjects
gas gangrene ,lcsh:Surgery ,lcsh:RD1-811 ,breast infection - Abstract
La gangrena gaseosa de la mama es una enfermedad rara y potencialmente mortal descrita como consecuencia de un traumatismo, por complicaciones infecciosas de la cirugía o por una trombosis venosa. También se ha relacionado ocasionalmente con otras causas tales como la diabetes mellitus, el envenenamiento con monóxido de carbono o la cirugía plástica. Presentamos un caso de gangrena gaseosa de mama en una mujer diabética de 74 años. Esta rara infección representa una emergencia médico-quirúrgica.
373. Evidence for Non-Local Thermodynamic Equilibrium in the v 3 Mode of Mesospheric CO2 from Stratospheric and Mesospheric Sounder Measurements
- Author
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Fredric W. Taylor, Miguel Lopez-Valverde, and Manuel López-Puertas
- Subjects
Source function ,Atmosphere ,Atmospheric radiative transfer codes ,Geography ,Meteorology ,Mean kinetic temperature ,Thermodynamic equilibrium ,Mode (statistics) ,Scale height ,Non local ,Atmospheric sciences - Abstract
The measurements of the 4.3 µm CO2 emission from the terrestrial atmosphere carried out by the Stratospheric and Mesospheric Sounder (SAMS) on Nimbus 7 are presented. The data cover radiances from 50oS to 70oN, altitudes from 30 km to 140 km, and have been taken during a period of nearly four years from 1978 to 1982. The most important features in the data are described and qualitatively discussed. The theoretical treatment necessary to analyze the data is developed. By using a non-LTE radiative transfer model, the mechanisms responsible for the most outstanding feature in the data, the large day to night difference in the radiances, have been established.
- Published
- 1988
374. Specific inhibitors distinguish the chloride channel and drug transporter functions associated with the human multidrug resistance P-glycoprotein
- Author
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Gm, Mintenig, Miguel A. Valverde, Fv, Sepulveda, Dr, Gill, Sc, Hyde, Kirk J, and Cf, Higgins
- Subjects
Membrane Glycoproteins ,Daunorubicin ,Drug Resistance ,Biological Transport, Active ,Cyclosporins ,Transfection ,Cell Line ,Electrophysiology ,Mice ,Verapamil ,Chloride Channels ,Nitrobenzoates ,Animals ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Carrier Proteins - Abstract
Expression of the human multidrug resistance P-glycoprotein is associated with two activities, active drug transport and a volume-regulated chloride channel. In this study we define four classes of compound, based on their differential effects on these two activities. Class I compounds are substrates transported by P-glycoprotein. They also prevent channel activation when added to the cytoplasmic face of the membrane. Class II compounds include reversers of multidrug resistance such as verapamil. These compounds inhibit drug transport and block the chloride channel when added to the outer face of the membrane. Class III compounds include conventional channel blockers which block the chloride channel but do not influence drug transport. Class IV compounds, for example cyclosporin A, appear to inhibit drug transport but do not affect chloride channel activity. These findings have implications for the relationship between the channel and transporter functions associated with P-glycoprotein expression, and for the development of clinical agents which reverse multidrug resistance.
375. Expanded use of a fast photography technique to characterize laser-induced plasma plumes
- Author
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Miguel A. Valverde-Alva, García-Fernández, T., Diáz-Cortés, G., Sánchez-Llamazares, J. L., Rodríguez-González, E., Sánchez-Aké, C., Quintana-Nedelcos, A., and Villagrán-Muniz, M.
- Subjects
fast photography ,plasma plume splitting ,Física, Astronomía y Matemáticas ,laser ablation ,digital image processing ,eye diseases ,Plasma diagnostics - Abstract
"Expanded use of fast photography is proposed to characterize laser ablation plasma plumes by the analysis of a set of photographs by means of appropriate mathematical algorithms. The laser ablation plasma plumes studied were generated by ablation of both a multicomponent target of the nominal composition Ni50 Mn37 Sn13 and a highly pure Cu target (Cu) using a Q-switched Nd-YAG laser system.The experiments were conducted under different background argon pressures. Several photograph parameters such as intensity per unit time of exposure for a pixel, mean intensity per pixel per unit time of exposure, integrated intensity and cross correlation were studied. The intensity per unit time of exposure allowed for identification of the fast component of the triple structure of the expanding plasma into the background gas (that travels at a speed close to the one measured in vacuum). This parameter together with the use of cross correlation enabled the identification of regions of the expanded plasma plume with higher and lower similarities in their optical emission behavior. The mean intensity per pixel per unit time of exposure can be used as a measurement of the amount of light emitted by the plume as a function of time."
376. Transfer of aversive respondent elicitation in accordance with equivalence relations
- Author
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Miguel Rodríguez Valverde, Carmen Luciano, and Dermot Barnes-Holmes
- Subjects
Adult ,Male ,Stimulus equivalence ,Adolescent ,Transfer, Psychology ,Conditioning, Classical ,Experimental and Cognitive Psychology ,Stimulus (physiology) ,Feedback ,Discrimination Learning ,Young Adult ,Behavioral Neuroscience ,Orientation ,Avoidance Learning ,Humans ,Equivalence relation ,Discrimination learning ,Research Articles ,Electroshock ,Association Learning ,Fear ,Galvanic Skin Response ,Aversive conditioning ,Pattern Recognition, Visual ,Respondent ,Conditioning ,Female ,Arousal ,Skin conductance ,Psychology ,Social psychology ,Psychomotor Performance ,Cognitive psychology - Abstract
The present study investigates the transfer of aversively conditioned respondent elicitation through equivalence classes, using skin conductance as the measure of conditioning. The first experiment is an attempt to replicate Experiment 1 in Dougher, Augustson, Markham, Greenway, and Wulfert (1994), with different temporal parameters in the aversive conditioning procedure employed. Match-to-sample procedures were used to teach 17 participants two 4-member equivalence classes. Then, one member of one class was paired with electric shock and one member of the other class was presented without shock. The remaining stimuli from each class were presented in transfer tests. Unlike the findings in the original study, transfer of conditioning was not achieved. In Experiment 2, similar procedures were used with 30 participants, although several modifications were introduced (formation of five-member classes, direct conditioning with several elements of each class, random sequences of stimulus presentation in transfer tests, reversal in aversive conditioning contingencies). More than 80% of participants who had shown differential conditioning also showed the transfer of function effect. Moreover, this effect was replicated within subjects for 3 participants. This is the first demonstration of the transfer of aversive respondent elicitation through stimulus equivalence classes with the presentation of transfer test trials in random order. The latter prevents the possibility that transfer effects are an artefact of transfer test presentation order.
377. Regulation of volume activated chloride channels by protein kinase C-mediated phosphorylation of P-glycoprotein
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Sp, Hardy, Miguel A. Valverde, Hr, Goodfellow, Cf, Higgins, and Fv, Sepúlveda
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Patch-Clamp Techniques ,Chloride Channels ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Phosphorylation ,Drug Resistance, Multiple ,Protein Kinase C ,HeLa Cells - Abstract
The multidrug resistance P-glycoprotein (Pgp) transports hydrophobic drugs out of cells and has been recently associated with volume-activated chloride channels. Activation of these channels by hypotonic swelling was seen to be prevented by protein kinase C (PKC) in cells expressing high levels of Pgp by transfection. HeLa cells possess equivalent chloride currents yet they are not regulated by PKC. HeLa cells do not express Pgp as assessed by Western blotting. Following transfection of HeLa cells with cDNA encoding for Pgp, PKC-dependent suppression of volume activated chloride currents was observed. PKC regulation in transiently transfected HeLa cells was abolished by alanine replacement of the serine/threonine residues in the consensus phosphorylation sites of the linker region of Pgp. Replacement of these residues with glutamate, to mimic the effect of phosphorylation, mimicked the effects of PKC on channel activation. These results indicate that overexpression of Pgp confers PKC-regulation of endogenous volume-activated chloride channels. More generally they favour a model in which Pgp acts as a regulator of volume-activated chloride channels.
378. The estrogen trinity: Membrane, cytosolic, and nuclear effects
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Angel Nadal, Miguel A. Valverde, and Mario Díaz
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medicine.medical_specialty ,Physiology ,medicine.drug_class ,Estrogen receptor ,Biology ,Cytosol ,Transcription (biology) ,Internal medicine ,medicine ,Animals ,Estrogen receptor beta ,PELP-1 ,Cell Nucleus ,Cell Membrane ,Estrogen Receptor alpha ,Estrogens ,Cell biology ,Receptors, Neurotransmitter ,Membrane ,medicine.anatomical_structure ,Endocrinology ,Receptors, Estrogen ,Estrogen ,Nucleus ,hormones, hormone substitutes, and hormone antagonists - Abstract
Estrogens have a wide array of biological effects, targeting both genomic and nongenomic mechanisms. Classically, the estrogen receptors activating the transcription machinery in the nucleus were thought to be distinct from the extranuclear estrogen receptors. Recently, this conceptual wall has started to be dismantled as the result of the identification of novel routes of estrogen action.
379. Non-local thermodynamic equilibrium limb radiances for the MIPAS instrument on envisat-1
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Rada Manuilova, F. J. Martín-Torres, Alexander A. Kutepov, A. Wegner, Hermann Oelhaf, Manuel López-Puertas, O. Gusev, Gabriele Stiller, G. M. Shved, David P. Edwards, J. M. Flaud, Andrea Linden, T. von Clarmann, Guillermo Zaragoza, and Miguel Lopez-Valverde
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Atmospheric sounding ,Radiation ,Materials science ,Infrared ,Thermodynamic equilibrium ,Analytical chemistry ,Michelson interferometer ,Non local ,Atmospheric sciences ,Atomic and Molecular Physics, and Optics ,Spectral line ,law.invention ,Volume (thermodynamics) ,law ,Spectroscopy - Abstract
An evaluation of the effects that the assumption of local thermodynamic equilibrium (LTE) has on the retrieval of pressure, temperature and the five primary target gases (O 3 , H 2 O, CH 4 , N 2 O, and HNO 3 ) from spectra to be taken by Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the Envisat-1 platform has been conducted. For doing so, non-LTE and LTE limb radiances in the spectral range of 680–2275 cm −1 (4.15–14.6 μm) with a resolution of 0.05 cm −1 at tangent heights from 10 to 70 km have been computed. These calculations included the most updated non-LTE populations of a large number of vibrational levels of the CO 2 , O 3 , H 2 O, CH 4 , N 2 O and HNO 3 molecules which cause the most prominent atmospheric infrared emissions. A discussion of the most important non-LTE effects on the limb radiances as well as on the retrievals of pressure-temperature and volume mixing ratios of O 3 , H 2 O, CH 4 , N 2 O, and HNO 3 is presented, together with the most important non-LTE issues that could be studied with the future coming of MIPAS data.
380. Cell sensing and decision-making in confinement: The role of TRPM7 in a tug of war between hydraulic pressure and cross-sectional area
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Selma A. Serra, Konstantinos Konstantopoulos, Christopher L. Yankaskas, Sean X. Sun, Yuqi Zhang, Runchen Zhao, Panagiotis Mistriotis, Shuyu He, Alexandros Afthinos, Tian Zhu, Yizeng Li, and Miguel A. Valverde
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Materials science ,Tug of war ,Entropy ,Hydrostatic pressure ,Cell ,TRPM Cation Channels ,macromolecular substances ,Protein Serine-Threonine Kinases ,Mechanotransduction, Cellular ,03 medical and health sciences ,0302 clinical medicine ,TRPM7 ,Cell Line, Tumor ,medicine ,Hydrostatic Pressure ,Humans ,Mechanotransduction ,Ion channel ,Actin ,Research Articles ,030304 developmental biology ,0303 health sciences ,Multidisciplinary ,Water ,SciAdv r-articles ,Actomyosin ,Cell Biology ,Hydraulic pressure ,medicine.anatomical_structure ,HEK293 Cells ,Biophysics ,Calcium ,Synthetic Biology ,Cell Surface Extensions ,Ion Channel Gating ,030217 neurology & neurosurgery ,Research Article - Abstract
TRPM7 senses hydraulic pressure and modulates cortical actomyosin to guide migrating cells towards the path of lower resistance., How cells sense hydraulic pressure and make directional choices in confinement remains elusive. Using trifurcating Ψ-like microchannels of different hydraulic resistances and cross-sectional areas, we discovered that the TRPM7 ion channel is the critical mechanosensor, which directs decision-making of blebbing cells toward channels of lower hydraulic resistance irrespective of their cross-sectional areas. Hydraulic pressure–mediated TRPM7 activation triggers calcium influx and supports a thicker cortical actin meshwork containing an elevated density of myosin-IIA. Cortical actomyosin shields cells against external forces and preferentially directs cell entrance in low resistance channels. Inhibition of TRPM7 function or actomyosin contractility renders cells unable to sense different resistances and alters the decision-making pattern to cross-sectional area–based partition. Cell distribution in microchannels is captured by a mathematical model based on the maximum entropy principle using cortical actin as a key variable. This study demonstrates the unique role of TRPM7 in controlling decision-making and navigating migration in complex microenvironments.
381. IP3 sensitizes TRPV4 channel to the mechano- and osmotransducing messenger 5'-6'-epoxyeicosatrienoic acid
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Miguel A. Valverde, Selma A. Serra, Anna Garcia-Elias, José M. Fernández-Fernández, Yaniré N. Andrade, Jacqueline Fernandes, and Ivan M. Lorenzo
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TRPV4 ,Osmosis ,Physiology ,TRPV Cation Channels ,Inositol 1,4,5-Trisphosphate ,Oviducts ,Biology ,Epoxyeicosatrienoic acid ,Mechanotransduction, Cellular ,Article ,chemistry.chemical_compound ,Transient receptor potential channel ,8,11,14-Eicosatrienoic Acid ,Phospholipase A2 ,Cricetinae ,Animals ,Humans ,Inositol 1,4,5-Trisphosphate Receptors ,Calcium Signaling ,Research Articles ,Calcium signaling ,Phospholipase C ,Temperature ,Calci ,Osmosi ,Cell Biology ,Inositol trisphosphate receptor ,Phospholipases A2 ,chemistry ,Biochemistry ,Type C Phospholipases ,Biophysics ,biology.protein ,Female ,Arachidonic acid ,lipids (amino acids, peptides, and proteins) ,HeLa Cells - Abstract
Mechanical and osmotic sensitivity of the transient receptor potential vanilloid 4 (TRPV4) channel depends on phospholipase A(2) (PLA(2)) activation and the subsequent production of the arachidonic acid metabolites, epoxyeicosatrienoic acid (EET). We show that both high viscous loading and hypotonicity stimuli in native ciliated epithelial cells use PLA(2)-EET as the primary pathway to activate TRPV4. Under conditions of low PLA(2) activation, both also use extracellular ATP-mediated activation of phospholipase C (PLC)-inositol trisphosphate (IP(3)) signaling to support TRPV4 gating. IP(3), without being an agonist itself, sensitizes TRPV4 to EET in epithelial ciliated cells and cells heterologously expressing TRPV4, an effect inhibited by the IP(3) receptor antagonist xestospongin C. Coimmunoprecipitation assays indicated a physical interaction between TRPV4 and IP(3) receptor 3. Collectively, our study suggests a functional coupling between plasma membrane TRPV4 channels and intracellular store Ca(2+) channels required to initiate and maintain the oscillatory Ca(2+) signal triggered by high viscosity and hypotonic stimuli that do not reach a threshold level of PLA(2) activation. This work was supported by grants from the Spanish Ministries of Education and Science (SAF2006-04973 and SAF2006-13893-C02-02), and Health (Fondo de Investigación Sanitaria, Red HERACLES RD06/0009), the Generalitat de Catalunya (SGR05-266), and Fundació la Marató de TV3 (061331). J.M. Fernández-Fernández is a Ramón y Cajal Fellow.
382. Atmospheric hazards for entry, descent and landing of future missions to Mars: Numerical simulations of fine-scale meteorological phenomena
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Vincent Bourrier, Luca Montabone, S. Portigliotti, T. Blancquaert, S. R. Lewis, L. Lorenzoni, J. P. Huot, L. Solovyeva, M. Dumontel, M.-C. Desjean, Jean-Baptiste Madeleine, Francisco Gonzalez-Galindo, Miguel Lopez-Valverde, François Forget, Ehouarn Millour, and Aymeric Spiga
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Martian ,Geography ,Meteorology ,Mesoscale meteorology ,Touchdown ,Mars Exploration Program ,Atmosphere of Mars ,Altimeter ,Interplanetary spaceflight ,Exploration of Mars - Abstract
In order to allow safe entry descent and landing, as well as mission surface operations, constraints apply to the selection of suitable landing sites. These constraints are defined in terms of general characteristics related to the specific mission profile (interplanetary transfer, waiting orbit injection and orbital waiting period and eclipse mitigation strategies) and to the EDL operations (entry conditions and environment, safe operation of the descent system with parachute deceleration, controlled rockets braking, touchdown with vented airbags). Most constraints are relative to « static » properties such as the geographical location, the altimetry, and the soil thermophysical constants. Few constraints are relative to the « dynamical » properties of the atmosphere, i.e. meteorological variations of density, temperature and winds, notwithstanding these are the most crucial characteristics to predict so as to ensure the success of the EDL phase. Martian mesoscale and microscale meteorological models are one of the relevant tools that can be used to predict the local and regional meteorological variability likely to be encountered at several proposed landing ellipses during Entry, Descent, and Landing. Most of the atmospheric hazards in the Martian lower atmosphere are not evident in current observational data and general circulation model simulations and can only be ascertained through mesoscale modeling of the region. The Laboratoire de Meteorologie Dynamique (LMD) Mesoscale Model is a versatile simulator of the Martian atmosphere and environment at horizontal scales ranging from hundreds of kilometers to tens of meters. Specific simulations with relevancy to assessment of atmospheric hazards possibly encountered in Martian landing sites can be carried out with such a tool. The need for accurate and realistic Martian mesoscale modeling remains critical for the design of upcoming missions to Mars (e.g., Mars Science Laboratory, ExoMars).
383. Upper atmosphere of Mars up to 120 km: Mars Global Surveyor accelerometer data analysis with the LMD general circulation model
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Miguel Lopez-Valverde, Stephen R. Lewis, M. Angelats i Coll, Peter L. Read, and François Forget
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Atmospheric Science ,Wave propagation ,Soil Science ,Forcing (mathematics) ,Aquatic Science ,Oceanography ,Physics::Geophysics ,Atmosphere ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Wavenumber ,Physics::Atmospheric and Oceanic Physics ,Earth-Surface Processes ,Water Science and Technology ,Ecology ,Paleontology ,Forestry ,Mars Exploration Program ,Atmosphere of Mars ,Geodesy ,Geophysics ,Amplitude ,Space and Planetary Science ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Longitude ,Geology - Abstract
Mars Global Surveyor (MGS) aerobraking accelerometer density measurements are analyzed with the use of the general circulation model (GCM) at the Laboratoire de Météorologie Dynamique (LMD). MGS constant altitude density data are used, obtaining longitudinal wavelike structures at fixed local times which appear to be dominated by low zonal wave number harmonics. Comparisons with simulated data for different seasons and latitudinal bands at constant altitude are performed. Excellent agreement is obtained between the simulated and observational data for low latitudes, with accuracy in both mean and zonal structure. Higher latitudes show a reduction in agreement between GCM results and MGS data. Comparisons that result in good agreement with the observational data allow for the study of wave composition in the MGS data. In particular, the excellent agreement between the simulations and the data obtained at 115 km during areocentric longitude Ls ≈ 65° allows the extraction of the major contributors to the signature, with the eastward propagating diurnal waves of wave numbers one to three being the major players. Significant contributions are also obtained for eastward propagating semidiurnal waves of wave numbers two, three, and five and diurnal wave number five. A sensitivity study is performed to delineate the effects of the near-IR tidal forcing of the upper atmosphere on the wave content at those heights. Simulations without this forcing yield reduced amplitudes for diurnal eastward propagating waves two and three along with a more latitudinally symmetric response for these two components as well as for diurnal eastward propagating wave number one. Copyright 2004 by the American Geophysical Union.
384. Potassium currents of isolated Necturus enterocytes: a whole-cell patch-clamp study
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Miguel A. Valverde, F. Giraldez, Francisco V. Sepúlveda, and David N. Sheppard
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Male ,Potassium Channels ,Physiology ,Enterocyte ,In Vitro Techniques ,Epithelium ,chemistry.chemical_compound ,Necturus ,Intestine, Small ,medicine ,Animals ,Patch clamp ,Membrane potential ,biology ,Electric Conductivity ,Conductance ,Tetraethylammonium ,Depolarization ,Tetraethylammonium Compounds ,biology.organism_classification ,Electrophysiology ,EGTA ,Kinetics ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Barium ,Biophysics ,Necturus maculosus ,Potassium ,Calcium ,Female ,Intracellular ,Research Article - Abstract
1. The whole-cell recording mode of the patch-clamp technique was used to investigate the ionic currents of enterocytes isolated from the small intestine epithelium of Necturus maculosus. 2. When enterocytes were bathed in a physiological Ringer solution and dialysed with a K(+)-rich intracellular solution containing 1.5 x 10(-7) M intracellular Ca2+, strongly outwardly rectifying currents were observed. These currents were absent from enterocytes internally dialysed with K(+)-free solutions. 3. The kinetics of activation of the outwardly rectifying current was monoexponential with rate constants decreasing with depolarization from 160 ms at 20 mV to 40 ms at 60 mV. Similar voltage dependence of the relaxations after activation were observed. 4. Strongly buffering intracellular Ca2+ with EGTA inhibited outward currents, while increasing Ca2+ increased both their magnitude and rate of activation. 5. Bath application of the K+ channel inhibitors Ba2+ and TEA greatly attenuated outwardly rectifying currents. This observation plus the fact that tail currents reverse near EK points to K+ as the charge carrier in these currents. 6. Outside-out patches showed maxi K+ channels and lower conductance K+ channels. Averaging fluctuations of the maxi K+ channels gave a kinetic behaviour similar to the whole-cell currents.
385. The multidrug resistance P-glycoprotein modulates cell regulatory volume decrease
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Miguel A. Valverde, Td, Bond, Sp, Hardy, Jc, Taylor, Cf, Higgins, Altamirano J, and Fj, Alvarez-Leefmans
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Potassium Channels ,Osmolar Concentration ,Down-Regulation ,3T3 Cells ,CHO Cells ,Mice ,Tamoxifen ,Spectrometry, Fluorescence ,Chloride Channels ,Cricetinae ,Animals ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Cell Size ,Research Article - Abstract
Cell volume is frequently down-regulated by the activation of anion channels. The role of cell swelling-activated chloride channels in cell volume regulation has been studied using the patch-clamp technique and a non-invasive microspectrofluorimetric assay for changes in cell volume. The rate of activation of these chloride channels was shown to limit the rate of regulatory volume decrease (RVD) in response to hyposmotic solutions. Expression of the human MDR1 or mouse mdr1a genes, but not the mouse mdr1b gene, encoding the multidrug resistance P-glycoprotein (P-gp), increased the rate of channel activation and the rate of RVD. In addition, P-gp decreased the magnitude of hyposmotic shock required to activate the channels and to elicit RVD. Tamoxifen selectively inhibited both chloride channel activity and RVD. No effect on potassium channel activity was elicited by expression of P-gp. The data show that, in these cell types, swelling-activated chloride channels have a central role in RVD. Moreover, they clarify the role of P-gp in channel activation and provide direct evidence that P-gp, through its effect on chloride channel activation, enhances the ability of cells to down-regulate their volume.
386. The detection of the hydroxyl nightglow layer in the mesosphere by ISAMS/UARS
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Fredric W. Taylor, Manuel López-Puertas, Miguel Lopez-Valverde, and Guillermo Zaragoza
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On board ,Satellite observation ,Geophysics ,Materials science ,Airglow ,Radiance ,General Earth and Planetary Sciences ,Satellite ,Atmospheric sciences ,Seasonal cycle ,Mesosphere - Abstract
Measurements of night-time radiance near 4.6 µm by the ISAMS instrument on board the UARS satellite exhibit an enhancement in the upper mesosphere. We show in this work that this increase around 85 km tangent height is due to the OH(9–8) and OH(8–7) Meinel bands. The ISAMS database therefore contains valuable information on the variability over a seasonal cycle of the OH high vibrational populations from which the chemical heating of the upper mesosphere can be derived.
387. Protein kinase C-mediated phosphorylation of the human multidrug resistance P-glycoprotein regulates cell volume-activated chloride channels
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Christopher F. Higgins, Simon P. Hardy, Miguel A. Valverde, Deborah R. Gill, H.R. Goodfellow, and V. Sepúlveda
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Models, Molecular ,Molecular Sequence Data ,General Biochemistry, Genetics and Molecular Biology ,3T3 cells ,Serine ,Mice ,Chlorides ,Chloride Channels ,Consensus Sequence ,medicine ,Animals ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Amino Acid Sequence ,Phosphorylation ,Threonine ,Molecular Biology ,Protein Kinase C ,Protein kinase C ,Cell Size ,P-glycoprotein ,Base Sequence ,General Immunology and Microbiology ,biology ,General Neuroscience ,3T3 Cells ,Molecular biology ,Drug Resistance, Multiple ,medicine.anatomical_structure ,Mutation ,Chloride channel ,biology.protein ,Tetradecanoylphorbol Acetate ,Signal transduction ,HeLa Cells ,Signal Transduction ,Research Article - Abstract
The multidrug resistance P-glycoprotein (P-gp), which transports hydrophobic drugs out of cells, is also associated with volume-activated chloride currents. It is not yet clear whether P-gp is a channel itself, or whether it is a channel regulator. Activation of chloride currents by hypotonicity in cells expressing P-gp was shown to be regulated by protein kinase C (PKC). HeLa cells exhibited volume-activated chloride currents indistinguishable from those obtained in P-gp-expressing cells except that they were insensitive to PKC. HeLa cells did not express detectable P-gp but, following transient transfection with cDNA encoding P-gp, the volume-activated channels acquired PKC regulation. PKC regulation was abolished when serine/threonine residues in the consensus phosphorylation sites of the linker region of P-gp were replaced with alanine. Replacement of these residues with glutamate, in order to mimic the charge of the phosphorylated protein, also mimicked the effects of PKC on channel activation. These data demonstrate that PKC-mediated phosphorylation of P-gp regulates the activity of an endogenous chloride channel and thus indicate that P-gp is a channel regulator.
388. Environmental estrogenic pollutants induce acute vascular relaxation by inhibiting L-type Ca2+ channels in smooth muscle cells
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Dietrich O. Ruehlmann, Miguel A. Valverde, Giovanni E. Mann, Ron Jacob, and Joern R. Steinert
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Male ,Insecticides ,Potassium Channels ,Calcium Channels, L-Type ,medicine.drug_class ,Muscle Relaxation ,Biochemistry ,Muscle, Smooth, Vascular ,Rats, Sprague-Dawley ,03 medical and health sciences ,chemistry.chemical_compound ,Human health ,0302 clinical medicine ,Phenols ,Smooth muscle ,Genetics ,medicine ,Animals ,Humans ,Fulvestrant ,Molecular Biology ,030304 developmental biology ,Pollutant ,0303 health sciences ,Estradiol ,Relaxation (psychology) ,Estrogen Antagonists ,Estrogens ,L type ca2 channels ,Calcium Channel Blockers ,Antiestrogen ,Coronary Vessels ,Rats ,3. Good health ,Nonylphenol ,chemistry ,13. Climate action ,Estrogen ,Biophysics ,Environmental Pollutants ,Female ,Calcium Channels ,030217 neurology & neurosurgery ,Biotechnology - Abstract
There is an ongoing scientific debate concerning the potential threat of environmental estrogenic pollutants to animal and human health (1-5). Pollutants including the detergents 4-octylphenol and p-nonylphenol and chlorinated insecticides have recently been reported to modulate sexual differentiation by interacting with nuclear steroid receptors (6-8). So far, the focus has been on reproductive organs, but sex steroids have far more widespread actions. The lower incidence of cardiovascular disease in women has been attributed to estrogens (9-14), yet no information is available on the vascular actions of environmental estrogenic pollutants. In the present study we have investigated the effects of acute exposure to 17beta-estradiol, the antiestrogen ICI 182,780, and estrogenic pollutants on coronary vascular tone as well as on intracellular Ca2+ levels ([Ca2+]i) and Ca2+ and K+ channel activity in vascular smooth muscle cells. We report here that 4-octylphenol, p-nonylphenol, o.p'-DDT, and the antiestrogen ICI 182,780 inhibit L-type Ca2+ channels in vascular smooth muscle cells and evoke a rapid and endothelium-independent relaxation of the coronary vasculature similar to that induced by 17beta-estradiol. Thus, inhibition of Ca2+ influx via L-type Ca2+ channels in vascular smooth muscle cells may explain the acute, nongenomic vasodilator actions of environmental estrogenic pollutants.
389. A non-local thermodynamic equilibrium radiative transfer model for infrared emissions in the atmosphere of mars 1. Theoretical basis and nighttime populations of vibrational levels
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Manuel López-Puertas and Miguel Lopez-Valverde
- Subjects
Atmospheric Science ,Thermodynamic equilibrium ,Population ,Soil Science ,Aquatic Science ,Oceanography ,Atmospheric sciences ,Mesosphere ,Troposphere ,Atmospheric radiative transfer codes ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Radiative transfer ,education ,Earth-Surface Processes ,Water Science and Technology ,Physics ,education.field_of_study ,Ecology ,Paleontology ,Forestry ,Atmosphere of Mars ,Geophysics ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Thermosphere - Abstract
A radiative transfer model to study the infrared (1–20 μm) emissions of the CO and CO2 molecules in the atmosphere of Mars has been developed. The model runs from the planet's surface up to 180 km and has been especially elaborated to study non-local thermodynamic equilibrium (non-LTE) situations. It includes the most important energy levels and vibration-rotation bands able to give a significant atmospheric emission or produce a significant cooling/heating rate. Exchanges of energy in thermal and nonthermal (vibrational-vibrational) collisions as well as by radiative processes have been included. An exhaustive review of the rate constants for vibrational-thermal and vibrational-vibrational collisional exchanges has been carried out. Radiative transfer processes have been treated by using a modified Curtis matrix formulation. The populations of the excited vibrational levels for nighttime conditions are presented along with a sensitivity study of their variations to the kinetic temperature profile and to collisional rate constants. The populations of the CO2(0,ν2,0) levels follow LTE up to about 85 km with the radiative transfer processes playing a very important role in maintaining this situation above the tropopause. This result is practically insensitive to plausible variations in the kinetic temperature of the troposphere. The uncertainties in the rate constants play an important role in determining the populations of the levels at thermospheric altitudes, but they are of little significance for the heights where they start departing from LTE. The CO2(0,0°,1) level breaks down from LTE at about 60 km, the laser bands at 10 μm giving a significant contribution to its population in the Martian mesosphere. The CO(1) level starts departing around 50 km and is noticeably enhanced in the upper thermosphere by absorption of upwelling flux from the planet's surface.
390. Small bowel mesenchymal tumors: description of two unusual cases
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Martínez Sanz N, Ruiz Marín M, Francisco Miguel González Valverde, Á, Sánchez Cifuentes, Aj, Fernández López, Fj, Ródenas Moncada, and Albarracín Marín Blázquez A
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Adult ,Ileal Neoplasms ,Male ,Treatment Outcome ,Gastrointestinal Stromal Tumors ,Humans ,Female ,lcsh:Diseases of the digestive system. Gastroenterology ,Middle Aged ,lcsh:RC799-869 - Abstract
We present two cases of intestinal ileal GIST who developed complications of nonspecific signs and required to be operated urgently, providing unusual images of tumors because of its characteristics.
391. Acute abdomen from duodenal diverticulitis: a case report
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Antonio José Fernández-López, Miguel González-Valverde, Nuria Martínez-Sanz, María Encarnación Tamayo-Rodríguez, and Antonio Albarracín-Marín-Blázquez
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Abdomen, Acute ,Aged, 80 and over ,Male ,Humans ,lcsh:Diseases of the digestive system. Gastroenterology ,Duodenal Diseases ,lcsh:RC799-869 ,Amoxicillin-Potassium Clavulanate Combination ,beta-Lactamase Inhibitors ,Diverticulitis - Abstract
Duodenal diverticula are a rare, usually asymptomatic clinical condition. When a complication arises clinical suspicion is key for the diagnosis. On occasion these patients receive a delayed diagnosis and undergo inadequate medical therapy. We report the case of a patient with evidence of duodenal diverticulitis in association with gallbladder inflammation by contiguity, as well as his diagnosis and management.
392. Fatal Heat Stroke in a Schizophrenic Patient
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Jesús Gómez Ramos, María, Miguel González Valverde, Francisco, Sánchez Álvarez, Carmen, Ortin Katnich, Lisa, and Pastor Quirante, Francisco
- Abstract
Objective. The case of a patient who developed a fatal post-exertional heat stroke is reported. Case Report. A 20-year-old man with a history of morbid obesity, hypertension, and schizophrenia was admitted to our intensive care unit because of multiorgan failure due to severe heat stroke. He had been working under the sun. Treatment included aggressive body cooling but, in spite of the best supportive care, the patient succumbed in a few hours. We concluded that the adverse event was possibly associated with his obesity and the use of antipsychotics. Histological evaluation revealed lesions consistent with severe hyperthermia and shock. Conclusions. Heat stroke is an uncommon clinical entity characterized by systemic heat and loss of the body's normal mechanisms for dealing with heat stress, such as sweating and temperature control. When heat stroke is diagnosed early and supportive care begins promptly the prognosis is optimal but it becomes a life-threatening disease when treatment is delayed. Lack of physical acclimatization and the use of certain medications that interfere with salt and water balance can impair thermoregulation under conditions of high environmental temperature. Health professionals must be adequately prepared to prevent, recognise, and treat them urgently.
- Published
- 2012
- Full Text
- View/download PDF
393. Testing the discrepancy between actual and ideal body image with the Implicit Relational Assessment Procedure (IRAP)
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Mónica Hernández-López, Lourdes Quiñones-Jiménez, Alberto L. Blanco-Romero, and Miguel Rodríguez-Valverde
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Figural drawings ,Body image ,Body dissatisfaction ,Implicit attitudes ,Implicit relational assessment procedure ,IRAP ,Psychiatry ,RC435-571 - Abstract
Plain English summary Body dissatisfaction can be thought of as the discrepancy between actual and desired body size. This is typically measured with rating scales depicting a series of body silhouettes of increasing size, from extreme thinness to fatness. Respondents mark the points that match their current body size and the one they would ideally like to be (the more distance between both, the more body dissatisfaction). Like all self-reports, these scales are liable to self-presentation biases. Experimental procedures that require respondents to answer under time pressure (implicit measures) tap into more automatic reactions that are less amenable to deliberate manipulation. This study used one such procedure (the IRAP) to examine how rapidly participants identified themselves (or not) with pictures of underweight or overweight, and how rapidly they expressed a desire to be (or not) like such pictures. Participants did not show a clear discrepancy between their actual and their ideal body size with the IRAP. However, automatic reactions indicative of acceptance/rejection of the idea of becoming fatter, predicted the degree of body image distress as measured with different instruments. Unwillingness to accept this idea was associated with more severe symptoms of disordered eating.
- Published
- 2021
- Full Text
- View/download PDF
394. The Role of Psychological Inflexibility and Experiential Approach on Mental Health in Children and Adolescents: An Exploratory Study
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Gloria Torres-Fernández, Miguel Rodríguez-Valverde, Salvador Reyes-Martín, and Mónica Hernández-Lopez
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psychological inflexibility ,experiential approach ,emotional intelligence ,mental health ,children ,Psychology ,BF1-990 - Abstract
The prevalence of mental health problems during childhood and adolescence is on the rise. There is a growing interest in the examination of personal variables that may function as risk factors and that may be targeted for effective intervention. This study explores the relationships amongst different aspects of psychological inflexibility (one, typically studied, focusing on the individual’s responding to unwanted emotions and cognitions, and another, more recently explored, focusing on the individual’s responding to desired thoughts and affective states), emotional intelligence, and mental health symptoms. A total of 129 school-going children (mean age: 11.16 years old) completed a battery of instruments comprising the Avoidance and Fusion Questionnaire-Youth (AFQ-Y17), the Experiential Approach Scale (EAS), the Emotional Intelligence Quotient Inventory (EQi-YV), and the Revised Child Anxiety and Depression Scale (RCADS-30). Results showed that both the AFQ-Y17 score and an EAS subscale score (Anxious Clinging) were significant independent predictors of mental health symptoms in general. Emotional intelligence was predictive only for depression, and both the AFQ-Y17 and the Anxious Clinging EAS subscale significantly incremented the predictive power of a hierarchical linear regression model including all three variables. These results underscore the relevance of psychological inflexibility for child/adolescent mental health, and the need to further explore a specific aspect of inflexibility regarding positive emotions and other appetitive private events.
- Published
- 2022
- Full Text
- View/download PDF
395. Giant Benign Senile Pyometra in Bicornuate Uterus
- Author
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José Luís Lobato Miguélez, María Victoria San Roman Sigler, and Miguel López Valverde
- Subjects
piometra ,supuración ,enfermedades uterinas ,anciano de 80 o mas años ,informes de casos ,Medicine (General) ,R5-920 ,Public aspects of medicine ,RA1-1270 - Abstract
Pyometra is an accumulation of pus in the endometrial cavity. It occurs when there is a stenosed cervical os as a result of malignant growths in the uterus or cervix, surgery or radiation therapy and senile atrophy. We present the case of an 84-year-old female patient referred to the Emergency Service of the Basurto University Hospital in Bilbao, Spain by the doctor of the nursing home where she is institutionalized because of a two-week history of continued fever without apparent cause. She was diagnosed with urinary tract infection and treated with amoxicillin/clavulanate. Based on the imaging tests, a pyometra in bicornuate uterus was diagnosed. She underwent drainage of the pyometra via the vaginal route, under general anesthesia, after mechanical dilation of the cervical canal. Treatment with ertapenen was prescribed. Progression was satisfactory. Given the rarity of this case, we decided to present it.
- Published
- 2014
396. Piometra senil benigno gigante en útero bicorne
- Author
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José Luís Lobato Miguélez, María Victoria San Roman Sigler, and Miguel López Valverde
- Subjects
piometra ,supuración ,enfermedades uterinas ,anciano de 80 o mas años ,informes de casos ,Medicine (General) ,R5-920 ,Public aspects of medicine ,RA1-1270 - Abstract
La piometra es una acumulación de pus en la cavidad endometrial. Aparece cuando existe una estenosis del orificio cervical debida a procesos malignos de cuerpo uterino o de cérvix, tras tratamientos con cirugía o radioterapia y por atrofia senil. Se presenta el caso de una paciente de 84 años remitida al Servicio de Urgencias Hospitalarias del Hospital Universitario Basurto, en Bilbao, España por el médico de la residencia donde se encuentra institucionalizada debido a que presentaba fiebre mantenida desde hacía dos semanas, sin focalidad aparente, diagnosticada como infección urinaria y tratada con amoxicilina-clavulánico. Por los exámenes imagenológicos se diagnosticó piometra en útero bicorne. Fue sometida al drenaje del piometra por vía vaginal, bajo anestesia general, tras dilatación mecánica del canal cervical. Se puso tratamiento con ertapenen. La evolución fue satisfactoria. Por lo poco común del caso se decidió su presentación.
- Published
- 2014
397. Fístula aortoentérica
- Author
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Silvia Navarro Moya and José Miguel Ramírez Valverde
- Subjects
Fístula aortoentérica ,Desgarro aórtico ,Anastomosis ,Medicine - Abstract
Paciente masculino de 75 años, con historia de uso de Ibuprofeno hace tres años, consulta por cuadro de hematemesis y melena, durante su valoración se palpa masa pulsátil a nivel de hipocondrio izquierdo, se realiza ultrasonido el cual documenta dilatación de aneurisma de aorta abdominal, valorado por el servicio de vascular periférico con sospecha diagnóstica de fístula aortoentérica, es llevado a sala de operaciones se realiza sustitución aorto-bi-ilíaca, fistulectomía aortoentérica con complicación de desgarro aórtico. Ingresa a la unidad de terapia intensiva para monitoreo, soporte ventilatorio y hemodinámico. Se lleva nuevamente a sala de operaciones y se realiza anastomosis duodenoyeyunal L-L, reintervenido para fijación de duodeno y finalmente se cierra por planos la cavidad abdominal. Presenta nuevo cuadro de deposiciones sanguinolentas, gastroscopía documenta restos hemáticos, no se identifica sitio de sangrado, paciente hemodinámicamente inestable, fallece
- Published
- 2016
- Full Text
- View/download PDF
398. Divertículos en yeyuno
- Author
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Silvia Navarro Moya and José Miguel Ramírez Valverde
- Subjects
Divertículos ,Diverticulosis ,Sangrado digestivo bajo ,Medicine - Abstract
Paciente masculino de 55 años, costarricense, constructor, con historia de sangrado digestivo alto secundario a consumo de anti-inflamatorios no esteroideos, consulta por cuadro de tres días de evolución de hematoquecia, se realiza gastroscopía que evidencia gastritis erosiva, por lo que paciente es egresado con tratamiento oral. Dos días después paciente reconsulta al servicio de emergencias con cuadro de hematoquecia, se documenta sangrado digestivo bajo, laboratorios evidencian anemia profunda por lo cual amerita transfusión masiva. La colonoscopía documenta divertículos aislados en colon sigmoides, el paciente es dejado en observación, y horasdespués presenta inestabilidad hemodinámica, por lo que se decide llevar a sala de operaciones, se documentan divertículos con sangrado activo en yeyuno y se resecan 80 cm del mismo. Paciente es trasladado a Unidad Cuidados Intensivos en el postoperatorio inmediato y es egresado seis días después sin complicaciones.
- Published
- 2016
- Full Text
- View/download PDF
399. Beneficios de la colostomía en la calidad de vida del paciente con lesión medular crónica y ventajas de su realización por vía laparoscópica
- Author
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Andres Leitón Chaves, Huxian Hu Liang, and Jose Miguel Ramírez Valverde
- Subjects
Colostomía ,laparoscopía ,lesión medular ,calidad de vida ,Medicine - Abstract
Las investigaciones recientes sugieren que el manejo de los problemas intestinales es una fuente importante de preocupación para los pacientes con lesión medular y puede alterar significativamente la calidad de vida. Los síntomas gastrointestinales más comunes hallados fueron estreñimiento e incontinencia fecal, reportado por 46% y 41%, respectivamente. Distensión abdominal se reportó en un 22% y el dolor gastrointestinal (dolor abdominal, rectal o anal) fue reportado por 33% de los pacientes. No es sorprendente que los síntomas gastrointestinales estén asociados con depresión, ansiedad, y deficiencias significativas en la calidad de vida en una parte significativa de las personas con lesión de médula espinal. Dada la gravedad de estos síntomas, varios autores han argumentado que las opciones quirúrgicas invasivas, incluyendo derivaciones intestinales (colostomía o ileostomía) o la creación de un Enema Anterógrado Continente de Malone (MACE), pueden proporcionar resultados superiores para determinados pacientes con disfunción intestinal neurogénica severa después de la lesión médular. Las ventajas de la colostomía laparoscópica resaltan, particularmente, la posibilidad de evitar una laparotomía amplia con todos sus riesgos. Algunos autores reportan menor formación de adherencias después de la laparoscopia lo que reduce riesgo de obstrucción y facilita la reconstrucción del tránsito en las colostomías temporales. La ventaja indiscutible es el acceso miniinvasivo a los pacientes.
- Published
- 2015
- Full Text
- View/download PDF
400. Evisceración intestinal transvaginal después de histerectomía Transvaginal intestinal evisceration after hysterectomy
- Author
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José Luis Lobato Miguelez, Amparo Villasante Moran, Carlos Pérez Sanjose, María Marques Melon, and Miguel López Valverde
- Subjects
Rotura vaginal ,evisceración vaginal ,Vaginal rupture ,vaginal evisceration ,Surgery ,RD1-811 - Abstract
La evisceración intestinal a través de la vagina después de una histerectomía es una complicación rara. Se presenta el caso de mujer posmenopáusica que presentó una evisceración transvaginal del intestino delgado después de que se le realizara una histerectomía abdominal. Se revisa la epidemiología, causas, diagnóstico y tratamiento.Transvaginal intestinal evisceration after hysterectomy is a uncommon complication. This is the case of a postmenopausal women presenting with transvaginal evisceration of the small intestine after a abdominal hysterectomy. Epidemiology, causes, diagnosis and treatment are analyzed.
- Published
- 2010
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