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1.
Nano Lett ; 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38624179

RESUMEN

The remarkable development of colloidal nanocrystals with controlled dimensions and surface chemistry has resulted in vast optoelectronic applications. But can they also form a platform for quantum materials, in which electronic coherence is key? Here, we use colloidal, two-dimensional Bi2Se3 crystals, with precise and uniform thickness and finite lateral dimensions in the 100 nm range, to study the evolution of a topological insulator from three to two dimensions. For a thickness of 4-6 quintuple layers, scanning tunneling spectroscopy shows an 8 nm wide, nonscattering state encircling the platelet. We discuss the nature of this edge state with a low-energy continuum model and ab initio GW-Tight Binding theory. Our results also provide an indication of the maximum density of such states on a device.

2.
Chem Mater ; 35(19): 8301-8308, 2023 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-37840776

RESUMEN

Cation exchange has become a major postsynthetic tool to obtain nanocrystals with a combination of stoichiometry, size, and shape that is challenging to achieve by direct wet-chemical synthesis. Here, we report on the transformation of highly anisotropic, ultrathin, and planar PbS nanosheets into CdS nanosheets of the same dimensions. We monitor the evolution of the Cd-for-Pb exchange by ex-situ TEM, HAADF-STEM, and EDX. We observe that in the early stages of the exchange the sheets show large in-sheet voids that repair spontaneously upon further exchange and annealing, resulting in ultrathin, planar, and crystalline CdS nanosheets. After cation exchange, the nanosheets show broad sub-band gap luminescence, as often observed in CdS nanocrystals. The photoluminescence excitation spectrum reveals the heavy- and light-hole exciton features, with very strong quantum confinement and large electron-hole Coulomb energy, typical for 2D ultrathin Cd-chalcogenide nanosheets.

3.
Acta Ortop Mex ; 37(4): 221-226, 2023.
Artículo en Español | MEDLINE | ID: mdl-38373732

RESUMEN

INTRODUCTION: hip revision arthroplasty surgery is a surgical procedure that has been growing in recent years. Revision total hip arthroplasty (THA) is a notable surgical challenge due to the technical difficulty of the surgery itself. Complications of revision surgery includes dislocation, aseptic loosening, and infection. OBJECTIVE: to compare the clinical-radiological results, as well as the incidence of complications, of two independent samples of patients who underwent revision total hip arthroplasty (rTHA) with mild-moderate acetabular defects using dual mobility implants compared to monopolar implants. MATERIAL AND METHODS: retrospective comparative study of two cohorts of 30 patients who underwent acetabular revision surgery using large 36 mm monopolar heads or dual mobility respectively. All patients had Paprosky type I or II acetabular defects. The results on the VAS scale, WOMAC, and Harry hip score (HHS) were evaluated pre and postoperatively in both cohorts. Likewise, the incidence of postoperative complications and the survival rate between both groups were analyzed. RESULTS: mean follow-up was 5.8 years (1-10.3 years). The difference between the pre and postoperative results in each cohort was significant for the VAS, WOMAC and HHS scale. The differences obtained in these scales between the different study groups did not find significant differences. The incidence of postoperative complications between both cohorts was similar, without finding significant differences. CONCLUSIONS: we consider that dual mobility does not provide superiority in terms of clinical-functional results and incidence of postoperative complications with respect to monopolar assemblies in acetabular revision surgery with mild-moderate defects.


INTRODUCCIÓN: la cirugía de revisión protésica de cadera constituye una indicación quirúrgica que se encuentra en crecimiento en los últimos años. La artroplastía total de cadera de revisión (ATCr) se trata de un reto quirúrgico destacado debido a la dificultad técnica de la propia cirugía. Entre las complicaciones de la cirugía de revisión des­tacan las luxaciones, el aflojamiento aséptico y la infección. OBJETIVO: comparar los resultados clínico-radiológicos, así como la incidencia de complicaciones, de dos muestras independientes de pacientes intervenidos de artroplastía total de cadera de revisión (ATCr) con defectos acetabulares leves-moderados utilizando implantes de doble movilidad respecto a implantes monopolares. MATERIAL Y MÉTODOS: estudio retrospectivo comparativo de dos cohortes de 30 pacientes intervenidos de cirugía de revisión acetabular mediante cabezas monopolares de 36 mm o doble movilidad, respectivamente. Todos los pacientes presentaban defectos acetabulares tipo I o II de Paprosky. Se evaluaron los resultados con las escalas EVA, WOMAC y Harry hip score (HHS) pre y postoperatorios en ambas cohortes. Asimismo, se analizaron la incidencia de complicaciones postoperatorias y la tasa de supervivencia entre ambos grupos. RESULTADOS: el seguimiento medio fue de 5.8 años (1-10.3 años). La diferencia entre los resultados pre y postoperatorios en cada cohorte fue significativa para la escala EVA, WOMAC y HHS. Las diferencias obtenidas en dichas escalas entre los distintos grupos de estudio no hallaron diferencias significativas. La incidencia de complicaciones postoperatorias entre ambas cohortes fue similar, sin encontrar diferencias significativas. CONCLUSIONES: consideramos que la doble movilidad no aporta superioridad en cuanto a resultados clínico-funcionales e incidencia de complicaciones postoperatorias respecto a los montajes monopolares en cirugía de revisión acetabular con defectos leves-moderados.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Humanos , Artroplastia de Reemplazo de Cadera/efectos adversos , Prótesis de Cadera/efectos adversos , Estudios Retrospectivos , Falla de Prótesis , Diseño de Prótesis , Acetábulo/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/cirugía , Reoperación/efectos adversos , Reoperación/métodos , Estudios de Seguimiento
4.
Acta Ortop Mex ; 36(2): 97-103, 2022.
Artículo en Español | MEDLINE | ID: mdl-36481550

RESUMEN

INTRODUCTION: femoral lengthening using an intramedullary nail is one of the surgical options in the treatment of severe lower limb dysmetria in routine clinical practice. MATERIAL AND METHODS: a retrospective descriptive study was carried out on a series of five patients with a mean age of 15.4 years, who underwent femoral lengthening surgery using a Precice® intramedullary nail. The etiology in all cases was idiopathic. Preoperative and definitive postoperative theoretical lengthening or dysmetry was measured, as well as lengthening accuracy, distraction rate and index (mm/day and days/cm, respectively) and consolidation index (days/cm). Intraoperative and postoperative complications were identified in all cases. RESULTS: mean follow-up was 21 months (12-42), with no loss to follow-up. The mean duration of the surgical procedure was 126 minutes (105-160). The preoperative theoretical dysmetry was 38 ± 2.7 mm. The final mean lengthening was 41 ± 7.5 mm. The mean accuracy was 108% (91-125) and the distraction rate was 0.9 ± 0.4 mm/day. The distraction rate was 13.9 ± 5.1 days/cm and the consolidation rate was 26.6 ± 9.1 days/cm. Bone consolidation was observed in all patients with a mean of 113 ± 58 days. Regarding complications, a total of four minor muscular complications were found. CONCLUSION: the Precice® intramedullary nail is a good treatment option for cases of severe femoral shortening, providing good clinical and radiological results with a low rate of complications and implant failure.


INTRODUCCIÓN: el alargamiento femoral mediante clavo intramedular es una de las opciones quirúrgicas en el tratamiento de las dismetrías severas de miembros inferiores en la práctica clínica habitual. MATERIAL Y MÉTODOS: se realizó un estudio descriptivo retrospectivo de una serie de cinco pacientes con una media de edad de 15.4 años, intervenidos de alargamiento femoral mediante clavo intramedular Precice®. La etiología en todos los casos fue idiopática. Se midió la dismetría o alargamiento teórico prequirúrgico y el definitivo postquirúrgico, así como la precisión del alargamiento, la tasa y el índice de distracción (mm/día y días/cm respectivamente) y el índice de consolidación (días/cm). Se identificaron las complicaciones intra y postoperatorias en todos los casos. RESULTADOS: la media de seguimiento fue de 21 meses (12-42), sin pérdidas en el seguimiento. La duración media del procedimiento quirúrgico fue de 126 minutos (105-160). La dismetría teórica prequirúrgica fue de 38 ± 2.7 mm. El alargamiento medio final fue de 41 ± 7.5 mm. La precisión media fue de 108% (91-125) y la tasa de distracción de 0.9 ± 0.4 mm/día. El índice de distracción fue de 13.9 ± 5.1 días/cm y el índice de consolidación, de 26.6 ± 9.1 días/cm. La consolidación ósea se observó en la totalidad de los pacientes con una media de 113 ± 58 días. Con respecto a las complicaciones, se encontraron un total de cuatro complicaciones menores de índole muscular. CONCLUSIÓN: el clavo intramedular Precice® es una buena opción de tratamiento para casos de acortamiento femoral severo aportando buenos resultados clínicos y radiológicos con una baja tasa de complicaciones y fallo del implante.


Asunto(s)
Alargamiento Óseo , Adolescente , Humanos , Estudios Retrospectivos
5.
Acta ortop. mex ; 36(2): 97-103, mar.-abr. 2022. tab, graf
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1505517

RESUMEN

Resumen: Introducción: el alargamiento femoral mediante clavo intramedular es una de las opciones quirúrgicas en el tratamiento de las dismetrías severas de miembros inferiores en la práctica clínica habitual. Material y métodos: se realizó un estudio descriptivo retrospectivo de una serie de cinco pacientes con una media de edad de 15.4 años, intervenidos de alargamiento femoral mediante clavo intramedular Precice®. La etiología en todos los casos fue idiopática. Se midió la dismetría o alargamiento teórico prequirúrgico y el definitivo postquirúrgico, así como la precisión del alargamiento, la tasa y el índice de distracción (mm/día y días/cm respectivamente) y el índice de consolidación (días/cm). Se identificaron las complicaciones intra y postoperatorias en todos los casos. Resultados: la media de seguimiento fue de 21 meses (12-42), sin pérdidas en el seguimiento. La duración media del procedimiento quirúrgico fue de 126 minutos (105-160). La dismetría teórica prequirúrgica fue de 38 ± 2.7 mm. El alargamiento medio final fue de 41 ± 7.5 mm. La precisión media fue de 108% (91-125) y la tasa de distracción de 0.9 ± 0.4 mm/día. El índice de distracción fue de 13.9 ± 5.1 días/cm y el índice de consolidación, de 26.6 ± 9.1 días/cm. La consolidación ósea se observó en la totalidad de los pacientes con una media de 113 ± 58 días. Con respecto a las complicaciones, se encontraron un total de cuatro complicaciones menores de índole muscular. Conclusión: el clavo intramedular Precice® es una buena opción de tratamiento para casos de acortamiento femoral severo aportando buenos resultados clínicos y radiológicos con una baja tasa de complicaciones y fallo del implante.


Abstract: Introduction: femoral lengthening using an intramedullary nail is one of the surgical options in the treatment of severe lower limb dysmetria in routine clinical practice. Material and methods: a retrospective descriptive study was carried out on a series of five patients with a mean age of 15.4 years, who underwent femoral lengthening surgery using a Precice® intramedullary nail. The etiology in all cases was idiopathic. Preoperative and definitive postoperative theoretical lengthening or dysmetry was measured, as well as lengthening accuracy, distraction rate and index (mm/day and days/cm, respectively) and consolidation index (days/cm). Intraoperative and postoperative complications were identified in all cases. Results: mean follow-up was 21 months (12-42), with no loss to follow-up. The mean duration of the surgical procedure was 126 minutes (105-160). The preoperative theoretical dysmetry was 38 ± 2.7 mm. The final mean lengthening was 41 ± 7.5 mm. The mean accuracy was 108% (91-125) and the distraction rate was 0.9 ± 0.4 mm/day. The distraction rate was 13.9 ± 5.1 days/cm and the consolidation rate was 26.6 ± 9.1 days/cm. Bone consolidation was observed in all patients with a mean of 113 ± 58 days. Regarding complications, a total of four minor muscular complications were found. Conclusion: the Precice® intramedullary nail is a good treatment option for cases of severe femoral shortening, providing good clinical and radiological results with a low rate of complications and implant failure.

6.
Chem Mater ; 33(17): 6853-6859, 2021 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-34552306

RESUMEN

The variation in the shape of colloidal semiconductor nanocrystals (NCs) remains intriguing. This interest goes beyond crystallography as the shape of the NC determines its energy levels and optoelectronic properties. While thermodynamic arguments point to a few or just a single shape(s), terminated by the most stable crystal facets, a remarkable variation in NC shape has been reported for many different compounds. For instance, for the well-studied case of CdSe, close-to-spherical quantum dots, rods, two-dimensional nanoplatelets, and quantum rings have been reported. Here, we report how two-dimensional CdSe nanoplatelets reshape into quantum rings. We monitor the reshaping in real time by combining atomically resolved structural characterization with optical absorption and photoluminescence spectroscopy. We observe that CdSe units leave the vertical sides of the edges and recrystallize on the top and bottom edges of the nanoplatelets, resulting in a thickening of the rims. The formation of a central hole, rendering the shape into a ring, only occurs at a more elevated temperature.

7.
J Phys Chem C Nanomater Interfaces ; 123(1): 979-984, 2019 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-30873253

RESUMEN

The unusual temperature dependence of exciton emission decay in CsPbX3 perovskite nanocrystals (NCs) attracts considerable attention. Upon cooling, extremely short (sub-ns) lifetimes were observed and were explained by an inverted bright-dark state splitting. Here, we report temperature-dependent exciton lifetimes for CsPbCl3 NCs doped with 0-41% Mn2+. The exciton emission lifetime increases upon cooling from 300 to 75 K. Upon further cooling, a strong and fast sub-ns decay component develops. However, the decay is strongly biexponential and also a weak, slow decay component is observed with a ∼40-50 ns lifetime below 20 K. The slow component has a ∼5-10 times stronger relative intensity in Mn-doped NCs compared to that in undoped CsPbCl3 NCs. The temperature dependence of the slow component resembles that of CdSe and PbSe quantum dots with an activation energy of ∼19 meV for the dark-bright state splitting. Based on our observations, we propose an alternative explanation for the short, sub-ns exciton decay time in CsPbX3 NCs. Slow bright-dark state relaxation at cryogenic temperatures gives rise to almost exclusively bright state emission. Incorporation of Mn2+ or high magnetic fields enhances the bright-dark state relaxation and allows for the observation of the long-lived dark state emission at cryogenic temperatures.

8.
Acta Crystallogr C Struct Chem ; 74(Pt 1): 1-6, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29303490

RESUMEN

The crystal structure of 5-fluorosalicylic acid is known from the literature [Choudhury & Guru Row (2004). Acta Cryst. E60, o1595-o1597] as crystallizing in the monoclinic crystal system with space-group setting P21/n and with one molecule in the asymmetric unit (polymorph I). We describe here a new polymorph which is again monoclinic but with different unit-cell parameters (polymorph II). Polymorph II has two molecules in the asymmetric unit. Its structure was modelled as a twin, with a pseudo-orthorhombic C-centred twin cell.

9.
Parasitology ; 144(4): 419-425, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28073394

RESUMEN

A high degree of specialization between host and parasite is a well-known outcome of a long history of coevolution, and it is strikingly illustrated in a coordination of their life cycles. In some cases, the arms race ensued at the establishment of a symbiotic relationship results in the adoption of manipulative strategies by the parasite. We have already learned that Steinina ctenocephali, a gregarine living in the alimentary canal of cat flea, Ctenocephalides felis follows its phenology and metamorphosis. Despite these findings the outcome of their symbiotic partnership (mutualist, parasitic or commensal) remains unclear. To address this important question, we measured life history parameters of the flea in the presence of varying infection intensities of gregarine oocysts in laboratory conditions. We found that neither the emergence nor survival rate of fleas was affected by harbouring the gregarines. More surprisingly, our results show that flea larvae infected with gregarines developed faster and emerged earlier than the control group. This gregarine therefore joins the selected group of protists that can modify physiological host traits and provides not only new model taxa to be explored in an evolutionary scenario, but also potential development of control strategies of cat flea.


Asunto(s)
Apicomplexa/fisiología , Ctenocephalides/parasitología , Animales , Apicomplexa/ultraestructura , Ctenocephalides/crecimiento & desarrollo , Ctenocephalides/ultraestructura , Femenino , Interacciones Huésped-Parásitos , Larva/crecimiento & desarrollo , Larva/parasitología , Larva/ultraestructura , Masculino , Oocistos
10.
Int. j. morphol ; 32(1): 61-69, Mar. 2014. ilus
Artículo en Inglés | LILACS | ID: lil-708724

RESUMEN

Poly (L-lactic acid) (PLA) nanoparticles have the approval of the main institutions for drugs administration and therapeutics. However, the use of lactic acid polymer is controversial because lactic acid has been proposed as an energy source for cancer cells. The aim of this study was to evaluate the cytotoxic, apoptotic and cell cycle properties of PLA and CuSO4-loaded PLA biodegradable nanoparticles on MKN-45 gastric adenocarcinoma cell line. PLA nanoparticles for the delivery of the anticancer active principle CuSO4 were obtained using the double emulsion method. PLA and CuSO4 loaded PLA nanoparticles were morphologically characterized and their size determined using transmission electron microscopy (TEM). The cytotoxicity of this drug delivery system was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; apoptosis was evaluated using YO-PRO-1/Propidium Iodide and cell cycle analysis throughout flow cytometry. CuSO4-loaded PLA nanoparticles were effective inhibitors of MKN45 cancer cell growth. They increased cytotoxicity and apoptosis, and induced G1/Go cell cycle arrest;whereas the anticancer activity was increased using a 96 h treatment of a minimal (1mM) concentration of CuSO4 loaded in 40 µM PLA nanoparticles. The treatment with 40 µM lactic acid and PLA (40 µM) did not increase the rate of cell survival assays related to the control, which indicate that PLA use as a polymer carrier not induce proliferation of MKN-45 cancer cells. Our research presents novel data about the effect of PLA nanoparticles and CuSO4 on gastric cancer cell line MKN45.


Las nanopartículas de ácido poli L-láctico (PLA) tienen la aprobación de las principales instituciones de administración de medicamentos y terapéutica. Sin embargo, el uso de polímero de ácido láctico es controvertido ya que el ácido láctico se ha propuesto como una fuente de energía para las células cancerosas. El objetivo de este estudio fue evaluar las propiedades citotóxicas, la apoptosis y sobre el ciclo celular de las nanoparticulas de PLA biodegradable y de estas PLA nanopartículas cargadas con CuSO4 en la línea celular de adenocarcinoma gástrico MKN-45. Las nanopartículas de PLA para la administración del principio activo CuSO4 contra el cáncer se obtuvieron utilizando el método de doble emulsión. Las nanopartículas de PLA y PLA cargadas con CuSO4 se caracterizan morfológicamente y su tamaño fue determinaron usando microscopía electrónica de transmisión (TEM). Se evaluó la citotoxicidad de este sistema de administración de fármacos utilizando la 3 - (4,5-dimetiltiazol-2-il) -2,5-ensayo difeniltetrazolio (MTT); la apoptosis se evaluó usando yoduro de propidio/YO-PRO-1 y el análisis de ciclo celular por citometría de flujo. Las nanopartículas cargadas con CuSO4-PLA fueron eficaces inhibidores del crecimiento de las células MKN-45 cancerosas. Aumentaron citotoxicidad y la apoptosis, e inducen la detención del ciclo celular en G1/Go, mientras que la actividad contra el cáncer se incrementó con el uso de un tratamiento de 96 horas con una concentración mínima (1 mM) de CuSO4 cargado en nanopartículas con 40 µM de PLA. El tratamiento con 40 µM de ácido láctico y 40 µM PLA no aumentó la tasa de supervivencia de células en relación con el control, lo que indica que el uso de PLA como un polímero portador que no induce la proliferación de células de cáncer MKN-45. Nuestro estudio presenta nuevos datos sobre el efecto de las nanopartículas de PLA con CuSO4 en la línea celular de cáncer gástrico MKN-45.


Asunto(s)
Humanos , Polímeros , Neoplasias Gástricas , Adenocarcinoma , Ácido Láctico , Antineoplásicos/administración & dosificación , Neoplasias Gástricas/patología , Adenocarcinoma/patología , Supervivencia Celular , Apoptosis , Sulfato de Cobre , Línea Celular Tumoral/efectos de los fármacos , Microscopía Electrónica de Transmisión , Emulsiones , Nanopartículas
12.
J Ethnopharmacol ; 103(2): 297-301, 2006 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-16310995

RESUMEN

The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid, 18-acetoxy-cis-cleroda-3-en-15-oic acid (10 betaH, 16 xi 19 beta, 17beta, 20 alpha form) (1), isolated as a major component from the resinous exudates of its twigs and leaves, together with the inactive 3,5-dihydroxy-6,7,3',4'-tetramethoxyflavone, n-alkanes and a few sesquiterpenoids.


Asunto(s)
Antiinfecciosos/química , Diterpenos/química , Haplopappus , Extractos Vegetales/química , Antiinfecciosos/aislamiento & purificación , Diterpenos/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/aislamiento & purificación , Relación Estructura-Actividad
13.
Heart Surg Forum ; 4(1): 57-60, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11510450

RESUMEN

Due to the fact that patients have increased mental alertness following off-pump coronary artery bypass (OPCAB), pain management in the immediate postoperative period is a major concern. Thirty-two patients underwent OPCAB grafting, 20 received 5 mcg/kg morphine sulfate intrathecally. This group was compared with 12 patients who did not receive intrathecal morphine. All patients were verbally evaluated for pain using the Wong-Baker Visual Analog Scale at eight, 12 and 24 hours. All the scores were highly statistically significant in favor of the intrathecal group. No significant complications were seen in this group of patients. It is concluded that intrathecal morphine at 5 mcg/kg is effective and safe in maintaining comfort for OPCAB patients in the immediate postoperative period.


Asunto(s)
Analgésicos Opioides/administración & dosificación , Puente de Arteria Coronaria , Morfina/administración & dosificación , Dolor Postoperatorio/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Puente de Arteria Coronaria/efectos adversos , Puente de Arteria Coronaria/métodos , Femenino , Humanos , Inyecciones Espinales , Masculino , Persona de Mediana Edad
14.
Rev Esp Cardiol ; 54(6): 685-92, 2001 Jun.
Artículo en Español | MEDLINE | ID: mdl-11412774

RESUMEN

INTRODUCTION AND AIMS: In patients with coronary risk factors the presence of endothelial dysfunction in epicardial arteries has been documented. The purpose of this study was to determine whether endothelial dysfunction, documented hypercholesterolemic patients and angiographically normal coronary arteries, improves by reduction and normalization of lipid levels. PATIENTS AND METHOD: In 10 patients with hypercholesterolemia and normal coronary angiography, the endothelium-dependent coronary vasomotion was studied by intracoronary infusion of acetylcholine into the left anterior descending coronary artery. Vasomotion changes in response to acetylcholine were analyzed by quantitative angiography. Five patients without coronary risk factors and normal coronary arteries formed the control group. Patients with hypercholesterolemia were treated with lipid-lowering therapy (diet and lovastatin) and endothelial function was reevaluated after 24 +/- 4 months. RESULTS: In the initial study, hypercholesterolemic patients compared with the control group showed a vasoconstrictor response to serial doses of acetylcholine(10(-6) M, 10(-5) M, 10(-4)M) indicative of endothelial dysfunction (study group: -0.3 +/- 10%, -6 +/- 4%, -18 +/- 10% vs control group: -0.6 +/- 6%, -2 +/- 6%, 3+/-6%; p < 0.01 to 10(-4) M acetylcholine dose. During follow-up hypercholesterolemic patients who a significant reduction in total cholesterol levels and LDL. Compared to first study, at follow-up, there was an improvement in the response to acetylcholine (-0.4 +/- 4%, -3 +/- 6%, -3 +/- 10%; p<0.001 vs basal values at 10(-4) M acetylcholine concentration). Reduction in total cholesterol during follow-up was related to the improvement in the vasoconstrictor response to acetylcholine (r=0.53; p< 0.05). CONCLUSION: In patients with hypercholesterolemia and angiographycally normal coronary arteries with documented endothelial dysfunction, the reduction and normalization of lipid levels during follow-up may improve endothelium-dependent coronary vasomotion.


Asunto(s)
Vasos Coronarios/fisiopatología , Hipercolesterolemia/sangre , Hipercolesterolemia/fisiopatología , Acetilcolina/farmacología , Adulto , Anciano , Colesterol/sangre , Vasos Coronarios/efectos de los fármacos , Endotelio Vascular/fisiopatología , Femenino , Humanos , Lipoproteínas HDL/sangre , Lipoproteínas LDL/sangre , Masculino , Persona de Mediana Edad , Triglicéridos/sangre , Vasodilatadores/farmacología
15.
Biochem Biophys Res Commun ; 273(2): 736-44, 2000 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-10873673

RESUMEN

This study aims to elucidate the signaling pathway for insulin-like growth factor-1 (IGF-1) in cultured neonatal rat cardiomyocytes and particularly the role of IGF-1 in cardiac apoptosis. IGF-1 stimulated polyphosphoinositide turnover, translocation of protein kinase C (PKC) isoforms (alpha, epsilon, and delta) from the soluble to the particulate fraction, activation of phospholipid-dependent and Ca(2+)-, phospholipid-dependent PKC, and activation of the extracellular-regulated kinase (ERK). IGF-1 attenuated sorbitol-induced cardiomyocyte viability and nuclear DNA fragmentation. These antiapoptotic effects of IGF-1 were blocked by PD-098059 (an MEK inhibitor) but not by bisindolylmaleimide I (BIM, a specific PKC inhibitor). The ERK pathway may therefore be an important component in the mechanism whereby IGF-1 exerts its antiapoptotic effect on the cardiomyocyte.


Asunto(s)
Factor I del Crecimiento Similar a la Insulina/farmacología , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteína Quinasa C/metabolismo , Animales , Apoptosis/efectos de los fármacos , Células Cultivadas , Inhibidores Enzimáticos/farmacología , Flavonoides/farmacología , Hidrólisis , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Miocardio/citología , Miocardio/metabolismo , Presión Osmótica , Fosfatidilinositoles/metabolismo , Proteína Quinasa C/antagonistas & inhibidores , Ratas , Transducción de Señal/efectos de los fármacos
16.
J Heart Lung Transplant ; 19(5): 453-61, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10808152

RESUMEN

BACKGROUND: Abnormal coronary vasomotion appears to be a common finding after heart transplantation (HTx). However, the pathophysiology and outcome of this functional disturbance remains poorly understood. Aims of the study were to determine the prevalence, predictive factors and long-term evolution of endothelial dysfunction after cardiac transplantation. METHODS: The endothelium-dependent coronary vasomotion of 50 patients, who showed angiographically normal coronary arteries, were studied early (at 3 +/- 1 months) and at follow-up (16 +/- 5 months) after HTx. Endothelial function was studied by selective infusion of serial doses of acetylcholine (ACh) (10(-8), 10(-7)and 10(-6) mol/l) in the left anterior descending coronary artery. Changes in mean luminal diameter after the infusion of each dose were evaluated by quantitative coronary angiography (QCA). RESULTS: At early study, 17 patients (34%) showed a vasoconstriction after maximal dose of ACh (-13.3 +/- 13%) indicative of endothelial dysfunction. Logistic regression analysis identified the following variables as independent predictors of early endothelial dysfunction: donor inotropic support (p = 0.004), female donor (p = 0.04) and rejection at the time of the study (p = 0.01). Forty-one patients were re-studied at follow-up. Nine of them (22%) presented endothelial dysfunction. Early endothelial dysfunction was restored in 6 patients (43%) at follow-up. The number of episodes of rejection was the only variable associated to late endothelial dysfunction. CONCLUSIONS: Endothelial dysfunction is a common finding after cardiac transplantation. The pathogenesis of this functional disturbance appears to be donor-related and immune-mediated. The reversibility of this phenomenon observed at follow-up suggests the episodic nature of the immunologic injury.


Asunto(s)
Enfermedad Coronaria/fisiopatología , Vasos Coronarios/fisiopatología , Endotelio Vascular/fisiopatología , Trasplante de Corazón , Vasoconstricción , Acetilcolina , Adulto , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/epidemiología , Vasos Coronarios/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Donantes de Tejidos , Vasoconstricción/efectos de los fármacos , Vasoconstricción/fisiología , Vasodilatadores
18.
Rev Esp Cardiol ; 52(7): 536, 1999 Jul.
Artículo en Español | MEDLINE | ID: mdl-10439682

RESUMEN

Myocardial infarction is an uncommon complication of electroconvulsive therapy. Because of this, in spite of the existence in psychiatric literature of some studies about this question, the knowledge in this regard by most cardiologists is scarce. We present a patient with an acute myocardial infarction after the application of a electroconvulsive therapy. In the end, we accomplish review of the literature in relation to incidence, physiology, prevention and indication or not of fibrinolytic drugs in acute myocardial infarction after electroconvulsive therapy.


Asunto(s)
Terapia Electroconvulsiva/efectos adversos , Infarto del Miocardio/etiología , Anciano , Femenino , Humanos
19.
Life Sci ; 64(18): 1603-12, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10328520

RESUMEN

There is some evidence that cardiac rather than circulating insulin-like growth factor-1 (IGF-1) levels contribute to the development of renovascular hypertensive left ventricular hypertrophy (LVH), remaining unknown the effects of antihypertensive drugs on IGF-1 levels. We have assessed here the preventive effects of enalapril, losartan, propanolol and alpha-methyldopa on left ventricle (LV) and circulating IGF-1 levels in a rat model of hypertension and LVH (Goldblatt, GB). Our results show that relative LV mass and the LV content of IGF-1 were significantly lower with all antihypertensive drugs in GB rats (p<0.001). Serum concentrations of IGF-1 were lower in GB rats treated with enalapril, alpha-methyldopa and propanolol (p<0.01), but not in those treated with losartan. These results support the hypothesis that local rather than seric IGF-1 contributes to the development of left ventricular hypertrophy induced by pressure overload in the rat.


Asunto(s)
Antihipertensivos/farmacología , Corazón/efectos de los fármacos , Hipertrofia Ventricular Izquierda/prevención & control , Factor I del Crecimiento Similar a la Insulina/metabolismo , Miocardio/metabolismo , Animales , Presión Sanguínea/efectos de los fármacos , Enalapril/farmacología , Losartán/farmacología , Masculino , Metildopa/farmacología , Propranolol/farmacología , Radioinmunoensayo , Ratas , Ratas Sprague-Dawley
20.
Rev Esp Cardiol ; 52(12): 1130-8, 1999 Dec.
Artículo en Español | MEDLINE | ID: mdl-10659658

RESUMEN

In-stent restenosis is an increasing problem due to the frequent use of coronary stent as a form of percutaneous revascularization. The global incidence is near to 28%, and it is well document that a neointimal hyperplasia is its principal mechanism. The most commonly related factors for its appearance are diabetes mellitus, a longer length of the original lesion, a smaller diameter of the reference vessel, the left anterior descending artery location and a smaller luminal diameter at the end of the procedure. Due to a different long term evolution in-stent restenosis has been classified as focal or diffuse, according to the length of the restenotic lesion (focal < 10 mm and diffuse > or = 10 mm). Some strategies have been proven for its treatment, but no randomized-controlled trials have been published comparing these different treatments. In focal in-stent restenosis the practice of a conventional balloon angioplasty is associated with high initial clinical success with a favourable long term evolution (target lesion revascularization between 11-15%). But on the contrary, in diffuse in-stent restenosis, in spite of a high initial success rate, an elevated target lesion revascularization has been detected at the follow-up (up to 43%). Other proved such as atherectomy or excimer laser are associated with a significant procedural non-Q-wave infarction (near to 9%) and a long term target lesion revascularization during follow-up (23-31%). The implantation of an additional stent has been performed with low procedural complications and with a long term target lesion revascularization near to 27%. Patients treated with intracoronary radiation as a complementary technique seem to have a better long term evolution than those having had the other strategies alone. In conclusion, in-stent-restenosis is a new and progressively more frequent problem, requiring complex treatment and of which as been established. Comparative controlled studies need to be performed in order to determine the best treatment for this new entity.


Asunto(s)
Enfermedad Coronaria/terapia , Stents , Angioplastia Coronaria con Balón , Aterectomía , Enfermedad Coronaria/clasificación , Enfermedad Coronaria/epidemiología , Enfermedad Coronaria/etiología , Humanos , Terapia por Láser , Prevalencia , Pronóstico , Radioterapia , Recurrencia , Retratamiento/métodos , Retratamiento/tendencias , Stents/estadística & datos numéricos
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