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1.
Nat Commun ; 13(1): 542, 2022 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-35087038

RESUMEN

Excitons play a dominant role in the optoelectronic properties of atomically thin van der Waals (vdW) semiconductors. These excitons are amenable to on-demand engineering with diverse control knobs, including dielectric screening, interlayer hybridization, and moiré potentials. However, external stimuli frequently yield heterogeneous excitonic responses at the nano- and meso-scales, making their spatial characterization with conventional diffraction-limited optics a formidable task. Here, we use a scattering-type scanning near-field optical microscope (s-SNOM) to acquire exciton spectra in atomically thin transition metal dichalcogenide microcrystals with previously unattainable 20 nm resolution. Our nano-optical data revealed material- and stacking-dependent exciton spectra of MoSe2, WSe2, and their heterostructures. Furthermore, we extracted the complex dielectric function of these prototypical vdW semiconductors. s-SNOM hyperspectral images uncovered how the dielectric screening modifies excitons at length scales as short as few nanometers. This work paves the way towards understanding and manipulation of excitons in atomically thin layers at the nanoscale.

2.
Nat Commun ; 12(1): 5741, 2021 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-34593793

RESUMEN

Twisted two-dimensional van der Waals (vdW) heterostructures have unlocked a new means for manipulating the properties of quantum materials. The resulting mesoscopic moiré superlattices are accessible to a wide variety of scanning probes. To date, spatially-resolved techniques have prioritized electronic structure visualization, with lattice response experiments only in their infancy. Here, we therefore investigate lattice dynamics in twisted layers of hexagonal boron nitride (hBN), formed by a minute twist angle between two hBN monolayers assembled on a graphite substrate. Nano-infrared (nano-IR) spectroscopy reveals systematic variations of the in-plane optical phonon frequencies amongst the triangular domains and domain walls in the hBN moiré superlattices. Our first-principles calculations unveil a local and stacking-dependent interaction with the underlying graphite, prompting symmetry-breaking between the otherwise identical neighboring moiré domains of twisted hBN.

3.
Diabetes Res Clin Pract ; 157: 107893, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31669628

RESUMEN

AIMS: We aimed to evaluate both glycaemic parameters and patient-reported outcomes in patients prescribed FGM based on the local criteria at our institution. METHODS: This retrospective observational study included patients aged > 18 years with a diagnosis of type 1 diabetes mellitus (T1DM) who were prescribed FreeStyle Libre FGM (n = 90). Quantitative data on glycaemic parameters was collected pre- and post-initiation of FGM in addition to patient-reported outcome measures (PROMs). The primary outcome was change in pre- and post-FGM levels of glycosylated haemoglobin (HbA1C). RESULTS: There was a mean reduction in HbA1c of -7.29 ±â€¯10.76 mmol/mol (p < 0.001, CI95% 4.94-9.64) sustained to the latest reading. There was also a mean reduction in the number of hypoglycaemic episodes per week of 3.20 (percentage reduction 51.86%, p < 0.001, CI95% 1.64-4.77). A significant improvement in quality of life scores was noted in all five domains of the abbreviated DDS between before and after starting FGM (p < 0.001). Key themes highlighted in inductive content analysis include 'life-changing', 'positive experience', and 'convenient'. CONCLUSION: Flash glucose monitoring is associated with significant improvement in HbA1c to a mean follow-up of 4.6 months. Additionally, patients reported positive experiences of FGM with significant improvement in all aspects of a focussed Diabetes Distress Scale.


Asunto(s)
Automonitorización de la Glucosa Sanguínea/métodos , Glucemia/metabolismo , Diabetes Mellitus Tipo 1/sangre , Medición de Resultados Informados por el Paciente , Calidad de Vida/psicología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
4.
Water Sci Technol ; 66(2): 275-83, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22699330

RESUMEN

The purpose of this paper is to introduce a geographic information system (GIS)-based decision support tool that assists the user to select not only areas where (retrofit) sustainable drainage systems (SuDS) could be implemented within a large catchment (>100 ha), but also to allow discrimination between suitable SuDS techniques based on their likely feasibility and effectiveness. The tool is applied to a case study catchment within London, UK, with the aim of increasing receiving water quality by reducing combined sewer overflow (CSO) spill frequency and volume. The key benefit of the tool presented is to allow rapid assessment of the retrofit SuDS potential of large catchments. It is not intended to replace detailed site investigations, but may help to direct attention to sites that have the greatest potential for retrofit SuDS implementation. Preliminary InfoWorks CS modelling of 'global disconnections' within the case study catchment, e.g. the removal of 50% of the total impervious area, showed that CSO spill volume could be reduced by 55 to 78% during a typical year. Using the disconnection hierarchy developed by the authors, the feasibility of retrofit SuDS deployment within the case study catchment is assessed, and the implications discussed.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Sistemas de Información Geográfica , Movimientos del Agua
5.
Int J Antimicrob Agents ; 28(6): 503-13, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17101263

RESUMEN

The minimum inhibitory concentration (MIC) of a homologous series of alcohol ethoxylates with the same head group size (E6) but differing in the number of carbon atoms in their 'tail group' from 10 to 16 was determined for Staphylococcus aureus NCTC 4163 and Escherichia coli NCTC 8196 using a turbidimetric assay. All the surfactants tested demonstrated bacteriostatic activity against both organisms. A tetrazolium assay showed that C14E6 and C16E6 had little effect on the membrane-bound dehydrogenase enzyme activity of E. coli NCTC 8196 compared with C10E6 and C12E6. C10E6 caused leakage both of K(+) and nucleotides in a concentration-dependent manner above its MIC of 0.2 mM. C12E6 caused some leakage at concentrations below its MIC (0.12 mM).


Asunto(s)
Alcoholes/farmacología , Antibacterianos/farmacología , Membrana Celular/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Tensoactivos/farmacología , Permeabilidad de la Membrana Celular/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos
6.
J Psychiatr Ment Health Nurs ; 12(1): 100-5, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15720503

RESUMEN

Hope. It is a word that is often used but one which we do not stop to think intentionally about. It may be difficult to define, and frequently many come to know it more by its absence. Nurses espouse the value of hope, but it is a concept that often seems elusive when one is trying to put it into practice. The author suggests that hope is at the heart of psychiatric nursing practice and provides insights and reflections about how it has made a difference in the lives of individuals.


Asunto(s)
Actitud , Acontecimientos que Cambian la Vida , Enfermería Psiquiátrica/métodos , Humanos , Servicios de Salud Mental , Relaciones Enfermero-Paciente , Pautas de la Práctica en Medicina
7.
Mar Pollut Bull ; 49(4): 291-4, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15341821

RESUMEN

Previous studies of neustonic debris have been limited to surface sampling. Here we conducted two trawl surveys, one before and one shortly after a rain event, in which debris and zooplankton density were measured at three depths in Santa Monica Bay, California. Surface samples were collected with a manta trawl, mid-depth samples with a bongo net and bottom samples with an epibenthic sled, all having 333 micron nets. Density of debris was greatest near the bottom, least in midwater. Debris density increased after the storm, particularly at the sampling site closest to shore, reflecting inputs from land-based runoff and resuspended matter. The mass of plastic collected exceeded that of zooplankton, though when the comparison was limited to plastic debris similar to the size of most zooplankton, zooplankton mass was three times that of debris.


Asunto(s)
Monitoreo del Ambiente/estadística & datos numéricos , Contaminación Ambiental/estadística & datos numéricos , Plásticos , Agua de Mar/análisis , Contaminantes del Agua/análisis , Zooplancton/fisiología , Animales , California , Densidad de Población , Lluvia
8.
Mar Pollut Bull ; 44(10): 1035-8, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12474963

RESUMEN

The density of neustonic plastic particles was compared to that of zooplankton in the coastal ocean near Long Beach, California. Two trawl surveys were conducted, one after an extended dry period when there was little land-based runoff, the second shortly after a storm when runoff was extensive. On each survey, neuston samples were collected at five sites along a transect parallel to shore using a manta trawl lined with 333 micro mesh. Average plastic density during the study was 8 pieces per cubic meter, though density after the storm was seven times that prior to the storm. The mass of plastics was also higher after the storm, though the storm effect on mass was less than it was for density, reflecting a smaller average size of plastic particles after the storm. The average mass of plastic was two and a half times greater than that of plankton, and even greater after the storm. The spatial pattern of the ratio also differed before and after a storm. Before the storm, greatest plastic to plankton ratios were observed at two stations closest to shore, whereas after the storm these had the lowest ratios.


Asunto(s)
Plásticos , Contaminantes del Agua/análisis , Zooplancton , Animales , California , Monitoreo del Ambiente , Tamaño de la Partícula , Dinámica Poblacional , Lluvia , Movimientos del Agua
9.
Mar Pollut Bull ; 44(6): 452-8, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12146828

RESUMEN

Most assessments of fish contamination in Southern California use ecologically different species from different sites. Use of ecologically similar species (a guild) might provide better assessments of fish contamination across different sites and depths. In July-August 1997, we collected samples of four sanddab guild species at 22 sites where species pairs co-occurred and determined total DDT concentrations in homogenized whole fish composites. Log-transformed DDT concentrations were highly correlated among all species pairs within this guild. All relationships were linear over the range observed, with slopes not statistically different from unity. The variability in response among species was about four times the variability encountered among replicates within species, but 15 times smaller than the variability among sites. Together, these results suggest that the sanddab guild, widespread on soft bottoms of the Southern California coastal shelf, can be used as a "superspecies" in bathymetrically diverse regional assessments of fish tissue contamination.


Asunto(s)
DDT/farmacocinética , Peces , Insecticidas/farmacocinética , Animales , California , Cadena Alimentaria , Dinámica Poblacional , Distribución Tisular
10.
Synapse ; 44(3): 146-57, 2002 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-11954046

RESUMEN

To determine whether metabotropic glutamate receptors (mGluRs) contribute to the responses of neurons to repetitive stimulation in the rat auditory cortex in vitro, five stimulus pulses were delivered at 2-100 Hz which elicited five depolarizing synaptic responses, f-EPSPs: f-EPSPs(1-5). Stimulus pulses 2-5 delivered at low frequencies (2-10 Hz) elicited f-EPSPs(2-5) that were about 15% smaller than the response elicited by the first pulse (f-EPSP(1)). In the presence of the nonspecific mGluR agonist, ACPD, the amplitude of all f-EPSPs was 40% smaller than predrug responses. APV, CNQX, or bicuculline (antagonists of NMDA-, AMPA/kainate-, and GABA(A)-receptors, respectively) did not change this effect of ACPD. The mGluR antagonist, MCPG, had no effect on f-EPSPs but did reduce the effect of ACPD. High-frequency stimulation (50-100 Hz) elicited f-EPSPs that were smaller with each successive stimulus. In ACPD, f-EPSP(1) was 40% smaller than predrug, but f-EPSPs(3-5) were not changed compared to pre-ACPD f-EPSPs(3-5), indicating that ACPD occludes the effect of repetitive stimulation. MCPG increased f-EPSP(5) by 15%, indicating that a portion of the reduction of f-EPSPs during high-frequency stimulation is mediated by mGluRs. MCPG also partially blocked the effect of ACPD. In CNQX, ACPD only decreased EPSPs, but APV or bicuculline did not change the effect of ACPD. These results suggest that the successive reduction of f-EPSPs during a high-frequency train is partially a result of mGluR activation.


Asunto(s)
Corteza Auditiva/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Animales , Corteza Auditiva/efectos de los fármacos , Corteza Auditiva/fisiología , Estimulación Eléctrica/métodos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Factores de Tiempo
11.
AJNR Am J Neuroradiol ; 22(7): 1383-5, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11498432

RESUMEN

Intraosseous hemangiomas are uncommon, constituting less than 1% of all osseous tumors. The most frequent sites are the calvaria and the vertebral column. Involvement of the facial bones is rare, and occurs most commonly in the maxilla, mandible, and nasal bones. Only 20 cases of zygomatic involvement have been reported in the English-language literature. We report a case of an intraosseous hemangioma of the zygoma documented by CT and MR studies.


Asunto(s)
Hemangioma/diagnóstico , Imagen por Resonancia Magnética , Neoplasias Craneales/diagnóstico , Tomografía Computarizada por Rayos X , Cigoma , Adulto , Diagnóstico Diferencial , Femenino , Humanos , Invasividad Neoplásica , Órbita/patología , Cigoma/patología
12.
Synapse ; 41(2): 118-30, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11400178

RESUMEN

Receptive-field plasticity within the auditory neocortex is associated with learning, memory, and acetylcholine (ACh). However, the interplay of elements involved in changing receptive-fields remains unclear. Herein, we describe a depolarizing and a hyperpolarizing potential elicited by repetitive stimulation (20-100 Hz, 0.5-2 sec) and dependent on ACh, which may be involved in modifying receptive-fields. These potentials were recorded, using whole cell techniques, in layer II/III pyramidal cells in the rat auditory cortex in vitro. Stimulation at low stimulus intensities can give rise to a hyperpolarizing response and stimulation at higher stimulus intensities can elicit a depolarizing response. The depolarizing response had a reversal potential of -35 mV, and was reduced by the combination of AMPA/kainate and NMDA glutamate receptor antagonists (AMPA/kainate: CNQX, DNQX, and GYKI 52466; NMDA: APV, MK-801) and by the muscarinic ACh receptor antagonist atropine. The hyperpolarizing response had a reversal potential of -73 mV and could be reduced by atropine, GABA(A) receptor antagonists (bicuculline and a Cl(-) channel blocker picrotoxin), and to a small extent a GABA(B) receptor antagonist (saclofen). This suggests that the hyperpolarizing response is likely to be mediated by ACh acting on GABAergic interneurons. Extracellular recordings, also made from layer II/III of cortical slices, yielded a negative-going potential which was reduced by ionotropic glutamate receptor antagonists (same as above) and by the ACh receptor antagonists atropine and scopolamine, suggesting that this potential was the extracellular representation of the depolarizing response.


Asunto(s)
Acetilcolina/metabolismo , Corteza Auditiva/metabolismo , Fibras Colinérgicas/metabolismo , Plasticidad Neuronal/fisiología , Neuronas/metabolismo , Sinapsis/metabolismo , Transmisión Sináptica/fisiología , Acetilcolina/farmacología , Animales , Corteza Auditiva/citología , Corteza Auditiva/efectos de los fármacos , Percepción Auditiva/efectos de los fármacos , Percepción Auditiva/fisiología , Fibras Colinérgicas/efectos de los fármacos , Estimulación Eléctrica , Electrofisiología , Antagonistas de Aminoácidos Excitadores/farmacología , Antagonistas del GABA/farmacología , Interneuronas/efectos de los fármacos , Interneuronas/metabolismo , Masculino , Antagonistas Muscarínicos/farmacología , Inhibición Neural/efectos de los fármacos , Inhibición Neural/fisiología , Plasticidad Neuronal/efectos de los fármacos , Neuronas/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de Glutamato/efectos de los fármacos , Receptores de Glutamato/metabolismo , Sinapsis/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Ácido gamma-Aminobutírico/metabolismo
13.
Mar Pollut Bull ; 42(3): 241-5, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11381879

RESUMEN

Many studies have quantified debris collected on beaches around the world. Only a few of those studies have been conducted in the United States, and they are largely limited to semi-quantitative efforts performed as part of volunteer clean-up activities. This study quantifies the distribution and composition of beach debris by sampling 43 stratified random sites on the Orange County, California coast, from August to September 1998. We estimated that approximately 106 million items, weighing 12 metric tons, occur on Orange County beaches. The most abundant items were pre-production plastic pellets, foamed plastics, and hard plastics. Debris density on the remote rocky shoreline was greater than that on high-use sandy beaches for most debris items. This finding partially reflects the periodic clean-up of high-use beaches by local municipalities, and also indicates that a high percentage of the observed debris was transported to the site from waterborne sources.


Asunto(s)
Monitoreo del Ambiente , Plásticos , Agua de Mar , Residuos , Contaminación del Agua/prevención & control , California , Monitoreo del Ambiente/métodos , Humanos
14.
Radiol Clin North Am ; 39(2): 329-42, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11316362

RESUMEN

The diagnosis of tuberculosis of the musculoskeletal system is difficult for many reasons. As Walker states, to diagnose tuberculosis one must consider the possibility. The uncommonness of osteoarticular MTb results in clinician inexperience, which leads to overlooking the diagnosis. Subtle early manifestations may elude detection. Negative skin tests and normal chest films do not exclude the consideration of tuberculosis. The most conclusive means of reaching the diagnosis (biopsy and culture) necessitate invasive procedures that are not always definitive, and may require repeated attempts. Management and surgical decisions, however, rely on prompt diagnosis; diagnostic delay has prognostic implications and results in significant morbidity. Musculoskeletal tuberculosis produces no pathognomonic imaging signs, and in advanced stages mimics other disease processes. Despite these difficulties, the diagnostician's goal is to catch the disease as early as possible, because antibiotic treatment can lead to resolution and obviate more radical management. The radiologist must be aware of the groups at greatest risk, and typical and atypical presentations at imaging. The eventual eradication of MTb is conceivable, although not presently within our grasp. Maintaining reasonable suspicion and developing cognizance of the patterns of presentation allow the radiologist to diagnose efficiently the patient who presents with osteoarticular tuberculosis.


Asunto(s)
Tuberculosis Osteoarticular/diagnóstico , Diagnóstico Diferencial , Humanos , Imagen por Resonancia Magnética , Columna Vertebral/diagnóstico por imagen , Columna Vertebral/patología , Tomografía Computarizada por Rayos X , Tuberculosis de la Columna Vertebral/diagnóstico
15.
Exp Brain Res ; 136(1): 25-40, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11204411

RESUMEN

In neocortex glutamate activates ionotropic and metabotropic receptors (mGluRs). Whole-cell current-clamp recordings in the in vitro rat auditory cortex at 32 degrees C were used to explore the role that mGluRs have in regulation of AMPA/kainate, NMDA, and GABA receptor-mediated synaptic transmission. Our findings are: (a) The fast EPSP (AMPA/kainate), slow EPSP (NMDA), and IPSPs (GABAA, GABAB), elicited in pyramidal neurons are reduced in the presence of (1S,3R)-ACPD (mGluR agonist) with greatest effect on the slow IPSP>fast IPSP>>fast EPSP. The effect is likely the result of ACPD acting at presynaptic mGluRs because the probability of release of glutamate and GABA is reduced in the presence of ACPD, intracellular infusion of a G protein antagonist (GDPPS) did not block the effect of ACPD, nor were iontophoretic kainic acid or NMDA-induced depolarizations reduced by ACPD. (b) The slow EPSP is enhanced following washout of ACPD and enhancement is not due to disinhibition because it is present in the absence of IPSPs, but if IPSPs are present, its magnitude can be influenced. Iontophoretic NMDA responses are enhanced in the presence of ACPD, an effect blocked by GDPbetaS and heparin (intracellular inositol 1,4,5-trisphosphate receptor antagonist). Taken together, this evidence suggests that enhancement is a result of group I postsynaptic mGluR activation. (c) In fast-spiking cells ACPD reduces the EPSP (AMPA/kainate and NMDA-mediated). This action is likely presynaptic because it persists when GDPbetaS is in the cells. (d) The rate of spike discharge recorded from fast-spiking cells is accelerated in ACPD but does not change in the presence of GDPbetaS, suggesting a postsynaptic effect. Our data indicate that mGluRs can influence neocortical synaptic transmission in complex ways by acting presynaptically and postsynaptically.


Asunto(s)
Cicloleucina/análogos & derivados , Potenciales Postsinápticos Excitadores/fisiología , Guanosina Difosfato/análogos & derivados , Interneuronas/fisiología , Células Piramidales/fisiología , Receptores de Ácido Kaínico/fisiología , Receptores de Glutamato Metabotrópico/fisiología , Transmisión Sináptica/fisiología , 6-Ciano 7-nitroquinoxalina 2,3-diona/farmacología , Animales , Corteza Auditiva/efectos de los fármacos , Corteza Auditiva/fisiología , Cicloleucina/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Guanosina Difosfato/farmacología , Interneuronas/efectos de los fármacos , Masculino , Neocórtex/efectos de los fármacos , Neocórtex/fisiología , Células Piramidales/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de Ácido Kaínico/efectos de los fármacos , Receptores de Glutamato Metabotrópico/agonistas , Transmisión Sináptica/efectos de los fármacos , Tionucleótidos/farmacología
16.
Mar Pollut Bull ; 42(12): 1297-300, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11827116

RESUMEN

The potential for ingestion of plastic particles by open ocean filter feeders was assessed by measuring the relative abundance and mass of neustonic plastic and zooplankton in surface waters under the central atmospheric high-pressure cells of the North Pacific Ocean. Neuston samples were collected at 11 random sites, using a manta trawl lined with 333 u mesh. The abundance and mass of neustonic plastic was the largest recorded anywhere in the Pacific Ocean at 334271 pieces km2 and 5114 g km2, respectively. Plankton abundance was approximately five times higher than that of plastic, but the mass of plastic was approximately six times that of plankton. The most frequently sampled types of identifiable plastic were thin films, polypropylene/monofilament line and unidentified plastic, most of which were miscellaneous fragments. Cumulatively, these three types accounted for 99% of the total number of plastic pieces.


Asunto(s)
Plásticos/análisis , Agua de Mar/análisis , Contaminantes del Agua/análisis , Zooplancton/crecimiento & desarrollo , Animales , Ritmo Circadiano , Monitoreo del Ambiente , Océano Pacífico , Zooplancton/aislamiento & purificación
17.
Shock ; 14(4): 441-6, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11049107

RESUMEN

Opioid receptor antagonists can act centrally and peripherally. It is unclear if these 2 pathways differentially mediate the perfusion-associated effects of opioid antagonism during endotoxemia. Male, Sprague-Dawley rats (340-390 g) were surgically prepared with left ventricular, tail artery, and jugular vein catheters 24 h before experiments were begun. Conscious, unrestrained rats were challenged with Escherichia coli lipopolysaccharide (LPS; 2 mg/kg/hr over 30 min) infusion. Measurements of regional blood flows were made using radioactive microspheres prior to (baseline), and at 60 and 120 min after LPS infusion. Saline (1 mL/kg bolus + 0.5 mL/kg/h infusion), naloxone (Nlx; 4 mg/kg bolus + 2 mg/kg/h infusion), or naloxone methyl bromide (Nlx-mb; 4.64 mg/kg, bolus + 2.32 mg/kg/h infusion) were administered 40 min after LPS infusion was begun. Nlx-mb does not cross the blood-brain barrier, and was thus used to differentiate central from peripherally mediated responses. At the end of each experiment, blood samples were collected for determination of ET-1 and nitric oxide metabolites (NOx = NO3 + NO2) using enzyme-linked immunosorbent assay (ELISA) and Griess reaction methods, respectively. Endotoxemia produced a significant decrease in cardiac output and an increase in systemic vascular resistance. Treatment with Nlx or Nlx-mb significantly attenuated the endotoxin-induced elevation in systemic vascular resistance and the decrease in cardiac output at 60 min after induction of endotoxemia compared with their respective baseline values. Nlx and Nlx-mb also attenuated the endotoxin-induced increases in hepatic portal and skeletal vascular resistances. These observations suggested that the ameliorative effect of Nlx on endotoxemia-induced regional vascular resistance alterations was mediated via peripheral opioid receptor mechanisms. However, although Nlx attenuated the endotoxin-induced decreases in the blood flow to the stomach and pancreas, Nlx-mb attenuated the endotoxin-induced decreases in the blood flow to the small intestine and cecum, in addition to the pancreas and, to some extent, the stomach. As such, separate central and peripherally mediated actions of opioid receptor antagonism were indicated. Nlx also resulted in an increase in the plasma levels of ET-1 only, whereas Nlx-mb increased the plasma levels of ET-1 and NOx. These observations suggest that separate central and peripheral effects of opioids during endotoxemia play a role in the associated circulatory alterations, and may differentially affect the release and/or synthesis of vasoactive mediators that might be related to their varied hepatosplanchnic vascular response during endotoxemia.


Asunto(s)
Endotoxemia/tratamiento farmacológico , Naloxona/farmacología , Antagonistas de Narcóticos/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Gasto Cardíaco/efectos de los fármacos , Endotelina-1/fisiología , Endotoxemia/fisiopatología , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Óxido Nítrico/fisiología , Ratas , Ratas Sprague-Dawley , Flujo Sanguíneo Regional/efectos de los fármacos , Resistencia Vascular/efectos de los fármacos
18.
Geriatr Nurs ; 21(1): 27-9, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10679607

RESUMEN

To make sense of their existence in the face of adversity and chaos or during times of relative calm, human beings seek meaning. Meaning has been identified as a significant factor in health and well-being in later years. Engaging in an intensive literature search about meaning in later life constituted the beginning step for a qualitative research study. By studying how older people experience meaning in their lives, we may learn more about the human experiences of joy and hope and their capacity to respond to opportunities and manage problems in their lives.


Asunto(s)
Adaptación Psicológica , Anciano/psicología , Enfermería Geriátrica , Humanos , Acontecimientos que Cambian la Vida
20.
Magn Reson Imaging Clin N Am ; 5(4): 755-65, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9314506

RESUMEN

The anatomy of the biceps brachii muscle-tendon complex is reviewed. Particular attention is given to the tendon of the long head. Pathologic conditions affecting the biceps are discussed with respect to clinical features and current ideas regarding pathogenesis, which are correlated with the appearance at MR imaging.


Asunto(s)
Músculo Esquelético/patología , Articulación del Hombro/patología , Hombro/patología , Tendones/patología , Brazo/anatomía & histología , Humanos
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