Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
J Antimicrob Chemother ; 70(7): 2048-52, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25749003

RESUMEN

OBJECTIVES: Increasing multidrug resistance amongst canine pathogenic staphylococci has renewed interest in topical antibacterial therapy for skin infections in the context of responsible veterinary prescribing. We therefore determined the activity in vitro of three clinically relevant topical agents and synergism between two of them against Staphylococcus pseudintermedius and Staphylococcus aureus. METHODS: The MICs of fusidic acid (n = 199), chlorhexidine (n = 198), miconazole (n = 198) and a 1:1 combination of miconazole/chlorhexidine (n = 198) were determined for canine isolates [50 MRSA and 49 methicillin-resistant S. pseudintermedius (MRSP), 50 MSSA and 50 methicillin-susceptible S. pseudintermedius (MSSP)] collected from the UK and Germany using an agar dilution method (CLSI VET01-A4). Fractional inhibitory concentration (FIC) indices were calculated to assess the interaction of miconazole with chlorhexidine. RESULTS: MICs of each drug/combination were significantly (P < 0.0005) higher for S. aureus when compared with S. pseudintermedius. Most strains (n = 172) had an MIC of fusidic acid of ≤0.03 mg/L (MIC ≥64 mg/L, n = 5 MRSA). All strains had MICs of chlorhexidine of 0.5-4 mg/L, except for one MRSA (MIC = 8 mg/L). All but four strains had MICs of miconazole of 1-4 mg/L (MIC = 16 mg/L, n = 3; MIC = 256 mg/L, n = 1). Miconazole/chlorhexidine (1:1 ratio) had a synergistic effect against 49/50 MRSA, 31/50 MSSA, 12/49 MRSP and 23/49 MSSP. CONCLUSIONS: Since the majority of these staphylococci, including methicillin-resistant isolates, had MICs that should be readily exceeded by topical skin application of these agents, their therapeutic efficacy for canine superficial pyoderma should be assessed. The synergistic interaction shown in vitro supports further clinical evaluation of miconazole/chlorhexidine combination therapy for staphylococcal infection.


Asunto(s)
Antibacterianos/farmacología , Clorhexidina/farmacología , Enfermedades de los Perros/microbiología , Ácido Fusídico/farmacología , Miconazol/farmacología , Infecciones Cutáneas Estafilocócicas/microbiología , Staphylococcus/efectos de los fármacos , Administración Tópica , Animales , Antibacterianos/uso terapéutico , Clorhexidina/uso terapéutico , Enfermedades de los Perros/tratamiento farmacológico , Perros , Sinergismo Farmacológico , Ácido Fusídico/uso terapéutico , Alemania , Miconazol/uso terapéutico , Pruebas de Sensibilidad Microbiana , Piodermia/tratamiento farmacológico , Piodermia/microbiología , Infecciones Cutáneas Estafilocócicas/tratamiento farmacológico , Staphylococcus/aislamiento & purificación , Reino Unido
2.
Opt Lett ; 39(11): 3238-41, 2014 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-24876022

RESUMEN

We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information. This scheme does not require access or active stabilization of the laser repetition rate. We implement and characterize this external lock, in the context of two-photon stimulated Raman transitions between the hyperfine ground states of trapped 171Yb(+) quantum bits.

3.
Nature ; 454(7204): 622-5, 2008 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-18668105

RESUMEN

Partial melting in the Earth's mantle plays an important part in generating the geochemical and isotopic diversity observed in volcanic rocks at the surface. Identifying the composition of these primary melts in the mantle is crucial for establishing links between mantle geochemical 'reservoirs' and fundamental geodynamic processes. Mineral inclusions in natural diamonds have provided a unique window into such deep mantle processes. Here we provide experimental and geochemical evidence that silicate mineral inclusions in diamonds from Juina, Brazil, crystallized from primary and evolved carbonatite melts in the mantle transition zone and deep upper mantle. The incompatible trace element abundances calculated for a melt coexisting with a calcium-titanium-silicate perovskite inclusion indicate deep melting of carbonated oceanic crust, probably at transition-zone depths. Further to perovskite, calcic-majorite garnet inclusions record crystallization in the deep upper mantle from an evolved melt that closely resembles estimates of primitive carbonatite on the basis of volcanic rocks. Small-degree melts of subducted crust can be viewed as agents of chemical mass-transfer in the upper mantle and transition zone, leaving a chemical imprint of ocean crust that can possibly endure for billions of years.

5.
Phys Rev Lett ; 109(2): 020503, 2012 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-23030141

RESUMEN

We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped ion systems. This extension of the Mølmer-Sørensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes.

6.
J Chem Phys ; 137(22): 224503, 2012 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-23249013

RESUMEN

Pressure induced densification in a molecular arsenic sulfide glass is studied at ambient temperature using x-ray scattering, absorption and Raman spectroscopic techniques in situ in a diamond anvil cell. The relatively abrupt changes in the position of the first sharp diffraction peak, FSDP, and the pressure-volume equation of state near ∼2 GPa suggest a phase transition between low- and high-density amorphous phases characterized by different densification mechanisms and rates. Raman spectroscopic results provide clear evidence that the phase transition corresponds to a topological transformation between a low-density molecular structure and a high-density network structure via opening of the constituent As(4)S(3) cage molecules and bond switching. Pressure induced mode softening of the high density phase suggests a low dimensional nature of the network. The phase transformation is hysteretically reversible, and therefore, reminiscent of a first-order phase transition.

7.
J Chem Phys ; 135(12): 124510, 2011 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-21974538

RESUMEN

The thermodynamic nature of phase stabilities and transformations are investigated in crystalline and amorphous Ge(1)Sb(2)Te(4) (GST124) phase change materials as a function of pressure and temperature using high-resolution synchrotron x-ray diffraction in a diamond anvil cell. The phase transformation sequences upon compression, for cubic and hexagonal GST124 phases are found to be: cubic → amorphous → orthorhombic → bcc and hexagonal → orthorhombic → bcc. The Clapeyron slopes for melting of the hexagonal and bcc phases are negative and positive, respectively, resulting in a pressure dependent minimum in the liquidus. When taken together, the phase equilibria relations are consistent with the presence of polyamorphism in this system with the as-deposited amorphous GST phase being the low entropy low-density amorphous phase and the laser melt-quenched and high-pressure amorphized GST being the high entropy high-density amorphous phase. The metastable phase boundary between these two polyamorphic phases is expected to have a negative Clapeyron slope.

8.
Br J Dermatol ; 163(6): 1340-5, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20649799

RESUMEN

Tenascin-X is a large extracellular matrix glycoprotein that is widely distributed within connective tissues and is associated with an autosomal recessive type of Ehlers-Danlos syndrome (EDS). Tenascin-X represents the first EDS susceptibility gene that does not code for a fibrillar collagen or collagen-processing enzyme. We describe a paediatric case of tenascin-X deficiency and review the literature.


Asunto(s)
Síndrome de Ehlers-Danlos/genética , Tenascina/deficiencia , Adulto , Niño , Análisis Mutacional de ADN , Síndrome de Ehlers-Danlos/patología , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Tenascina/genética
10.
Science ; 241(4870): 1203-5, 1988 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-3045968

RESUMEN

A new instrument has been developed for the electrophoretic separation of large DNA molecules that can independently regulate the voltage of each of 24 electrodes and allow the magnitude, orientation, homogeneity, and duration of the electric field to be precisely controlled. Each parameter can be varied at any time during the electrophoretic process. Thus distinct sets of conditions can be combined to optimize the separation of various fragment sizes in a single run. Independent control of electrode voltage allows all of the fields to be generated with electrodes arranged in a closed contour, independent of a particular geometry. This device increases both the resolution in any size range and the speed of separation, especially for DNA molecules larger than 3 megabases.


Asunto(s)
ADN/aislamiento & purificación , Electroforesis en Gel de Agar/instrumentación , Electroforesis/instrumentación , ADN de Hongos/aislamiento & purificación , Peso Molecular , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética
11.
Curr Opin Biotechnol ; 4(1): 69-74, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7763397

RESUMEN

The past few years have seen a tremendous renaissance in biological optical microscopy, mainly as a result of the application of digital image processing and video imaging techniques. We review recent developments in microscopy that are permitting unprecedented views of biological structure and function.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Microscopía/métodos , Animales , Humanos , Imagen por Resonancia Magnética , Microscopía Fluorescente/métodos , Microscopía de Túnel de Rastreo , Óptica y Fotónica
12.
Neurobiol Aging ; 1(2): 175-80, 1980.
Artículo en Inglés | MEDLINE | ID: mdl-24279943

RESUMEN

There is long-standing controversy as to whether fever capacity is reduced in aged man. Although loss of this cardinal sign of disease would be an impediment to diagnosis and treatment, there has been no previous research on altered febrile responses using aged primate models. In the present experiments the febrile reaction to IV Salmonella typhosa endotoxin was reduced in monkeys over 14 years old and in one-third of those 10-14 years of age compared with that of younger animals. In response to injections of endotoxin into the lateral cerebral ventricle (ICV), animals over 10 years old showed small or no fevers. Injections of probenecid (ICV), an inhibitor of central inactivation of leukocytic pyrogen and prostaglandin, augmented fever caused by IV and ICV endotoxin and hyperthermia caused by ICV PGE2 in animals under 10 years of age. However, in older animals probenecid increased fever caused by ICV endotoxin only, although the increased response was still less than one quarter that of younger animals. The results indicate that old squirrel monkeys have decreased febrile responses that may be traced to alterations in central sensitivity to pyrogens.

13.
Biotechniques ; 6(8): 776-7, 781-7, 1988 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-3273640

RESUMEN

We report here a system for automation of the dideoxynucleotide DNA sequencing method. The system consists of a Beckman Biomek 1000 robotic workstation which has been modified by the addition of a thin heater/cooler block directly on the instrument table. The heater/cooler block, which is regulated by a user-specified program integrated into the Biomek software, facilitates the use of both single- and double-stranded DNA sequencing procedures. Using this system, we are able to perform 24 sets of dideoxynucleotide DNA sequencing reactions in approximately 45 min. The reactions are performed in 96-well microtiter plates, using a prepared reagent pack which includes primer, enzyme, nucleotide mixes and radioactive label. Using standard gel electrophoresis technology, we are able to resolve over 500 nucleotides per sequencing reaction in about 5 h. Currently, we are able to perform three runs of 24 samples each, with subsequent gel analysis per 8-h period. Excluding autoradiography, this represents a daily data output of 36,000 base pairs.


Asunto(s)
ADN/análisis , Robótica/instrumentación
14.
J Thorac Cardiovasc Surg ; 103(4): 678-82, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1548910

RESUMEN

The standard treatment of innominate artery compression of the trachea has been innominate artery suspension, but the syndrome can recur when this technique is used. From October 1985 until March 1991, 29 infants and children were treated for this syndrome by innominate artery reimplantation. In all patients severe anterior vascular compression of the trachea was demonstrated preoperatively by bronchoscopy and in 17 the diagnosis was confirmed by magnetic resonance imaging scanning. Indications for operation included apneic episodes in 17 (58.6%), severe stridor in seven (24.1%), recurrent bronchopulmonary infections in four (13.8%), and exercise-induced stridor in one (3.4%). Through a median sternotomy, the innominate artery was reimplanted more proximally on the ascending aorta and to the right of the trachea. In this new position, the innominate artery no longer crosses the trachea anteriorly, and the anatomic cause of tracheal obstruction is completely eliminated. There were no early or late deaths, and 27 of the 29 patients (93%) had complete resolution of symptoms. Partial resolution of symptoms was seen in two patients (7%). Reimplantation of the innominate artery offers a unique method by which the anatomic cause of tracheal compression is eliminated. It is a safe and effective means of treating symptomatic compression of the trachea by the innominate artery.


Asunto(s)
Tronco Braquiocefálico/anomalías , Tronco Braquiocefálico/cirugía , Reimplantación/métodos , Estenosis Traqueal/etiología , Adolescente , Broncoscopía , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino
15.
Ann Thorac Surg ; 57(2): 293-6; discussion 296-7, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8311587

RESUMEN

Prenatal correction of certain cardiac lesions with a poor prognosis may have advantages over postnatal repair. For this to be done, safe and effective support of the fetal circulation must be devised. Studies involving fetal cardiac bypass have demonstrated progressive fetal hypoxemia, hypercapnia, and acidosis, indicating placental dysfunction. We performed fetal cardiac bypass in 18 fetal lambs (126 to 140 days' gestation) to assess the effect of flow rate on fetal oxygenation and metabolism and function of the placenta as an in vivo oxygenator. Fetal cardiac bypass was done for a 30-minute study period at normothermia in all fetuses. During the study period the fetal aorta was cross-clamped and cold cardioplegia was administered to the heart so there was no fetal cardiac contribution to systemic output. Nine fetuses underwent studies at low flow rates (109 +/- 20 mL.kg-1.min-1) and 9 at higher flow rates (324 +/- 93 mL.kg-1.min-1). At the lower flow rate, mean aortic pressure, arterial pH, and oxygen tension decreased whereas carbon dioxide tension and lactate levels increased when compared with prebypass levels. At the higher flow rate mean aortic pressure, pH, oxygen tension, carbon dioxide tension, and lactate levels remained similar to prebypass levels during the 30-minute study period. When the animals were weaned from the bypass circuit after studies at high flow rates, arterial oxygen tension and pH decreased whereas carbon dioxide tension increased to levels similar to those in the low-flow group.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Puente Cardiopulmonar/métodos , Corazón Fetal/cirugía , Animales , Velocidad del Flujo Sanguíneo , Dióxido de Carbono/sangre , Femenino , Feto/metabolismo , Paro Cardíaco Inducido , Lactatos/sangre , Oxígeno/sangre , Presión Parcial , Placenta/irrigación sanguínea , Placenta/fisiología , Embarazo , Ovinos
16.
Brain Res Bull ; 7(1): 5-9, 1981 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7272788

RESUMEN

Hypothermia was produced by IM administration of diazepam (0.125-0.5 mg/kg) to squirrel monkeys of various ages (2-16 years) in a thermoneutral (23 +/- 0.5 degrees C) environment with animals over eight years of age having slightly greater responses. Hypothermia caused by an intermediate dose (0.25 mg/kg) was augmented in a cold environment (15 degrees C), especially in the older animals. There was no marked alteration in the temperature change/age regression after 0.25 mg/kg diazepam in a hot environment (30 degrees C) compared with the control response. Injections of diazepam (1.25-5.0 microgram) into the lateral cerebral ventricle in a thermoneutral environment produced hyperthermia rather than hypothermia in all animals, and the magnitude of the induced hyperthermia was smaller in older monkeys. The results support previous case reports in man and suggest that this commonly used drug can induce hypothermia, especially in older primates exposed to cold. The drug action responsible for this temperature change appears to take place peripherally rather than within the brain.


Asunto(s)
Envejecimiento , Regulación de la Temperatura Corporal/efectos de los fármacos , Diazepam/farmacología , Animales , Relación Dosis-Respuesta a Droga , Inyecciones Intramusculares , Inyecciones Intraventriculares , Saimiri
17.
Brain Res Bull ; 10(3): 305-8, 1983 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-6850359

RESUMEN

Increased sensitivity to certain drugs is believed to contribute to dysthermia in the elderly. To learn whether the temperature-altering effects of an opiate are increased in aged primates, injections of morphine sulfate (0.5-4 mg/kg) were given SC in randomly assigned order to squirrel monkeys ranging in age from 3.5 to over 17 years. Hyperthermia was the predominant response with no clear relationship to age, although hypothermic and biphasic responses also occurred, most commonly after the highest dose. Lateral cerebral ventricular injections of 0.625 and 1.25 micrograms morphine sulfate evoked hyperthermia in monkeys over 8 years of age but did not affect the temperature of animals less than 5 years old. Doses of 2.5 and 5 micrograms usually elicited hyperthermia regardless of age, but 10 micrograms induced hypothermia in a majority of monkeys. Naloxone was given intraventricularly to several monkeys to limit the degree of hypothermia after high doses of morphine given peripherally or centrally. Thus in these primates, as in other species such as the rat, lower doses of morphine usually evoked hyperthermia, but sufficiently high doses caused body temperature to fall. Unlike the case in the squirrel monkey with diazepam and with endogenous substances such as leukocytic pyrogen and taurine, there was not a strong or consistent relationship between age and morphine-induced temperature changes.


Asunto(s)
Temperatura Corporal/efectos de los fármacos , Morfina/farmacología , Envejecimiento , Animales , Regulación de la Temperatura Corporal/efectos de los fármacos , Femenino , Masculino , Saimiri
18.
Cardiol Clin ; 19(3): 347-55, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11570109

RESUMEN

In conclusion, much has been learned about the effects of exercise in reducing events in those with CHD. Some data are confusing, however, and some gaping holes exist in our understanding. Hopefully, new data forthcoming in the next 5 to 10 years will clear up this picture significantly. Meanwhile, cardiovascular exercise, coupled with other risk factor reduction, has been firmly established as a lifesaving and life-improving tool in those who have developed manifestations of CHD.


Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Enfermedad Coronaria/prevención & control , Ejercicio Físico , Infarto del Miocardio/prevención & control , Enfermedades Cardiovasculares/mortalidad , Ensayos Clínicos como Asunto , Enfermedad Coronaria/mortalidad , Humanos , Infarto del Miocardio/mortalidad , Factores de Riesgo , Tasa de Supervivencia
19.
J Med Entomol ; 28(1): 186-9, 1991 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-2033612

RESUMEN

In 32 collections, two larvae, 33 nymphs, and one adult female Ixodes cookei Packard were collected from humans in West Virginia from August 1987 to May 1990. Most were attached. The ticks were found in 14 counties and were the most abundant Ixodes found biting humans. One nymphal I. cookei was removed from the left axilla of a 39-yr-old woman who lives and works in Monongalia and Marion counties, W. Va. The bite was the center of an expanding erythematous lesion reaching 4 cm in diameter, clearing centrally, and typical of erythema migrans. This association and the near absence of Ixodes dammini Spielman, Clifford, Piesman & Corwin from the state suggests the possibility that I. cookei may be an important vector of Lyme borreliosis in West Virginia. In five separate collections, five nymphal Ixodes dentatus Marx were removed from humans in four counties, implicating this species as a potential minor vector of Lyme borreliosis in West Virginia.


Asunto(s)
Vectores Arácnidos/aislamiento & purificación , Grupo Borrelia Burgdorferi/aislamiento & purificación , Enfermedad de Lyme/transmisión , Infestaciones por Garrapatas/parasitología , Garrapatas/aislamiento & purificación , Adulto , Animales , Vectores Arácnidos/microbiología , Femenino , Humanos , Persona de Mediana Edad , Garrapatas/microbiología , West Virginia
20.
J Periodontol ; 64(7): 645-50, 1993 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8366413

RESUMEN

The study was designed to evaluate whether root surface debridement with a sonic scaler plastic insert would cause less pain and discomfort to patients than an ordinary, probe-shaped metal sonic insert. One quadrant in each of 23 patients was debrided with each insert. Blood pressure, mean arterial pressure, and heart rate were monitored before, during, and immediately after each treatment. Pain was also evaluated on a visual analogue scale (VAS) after each treatment, as well as 2 weeks later following pain-provoking stimuli. Blood pressure, mean arterial pressure, and heart rate did not reveal any differences between quadrants treated with plastic or metal inserts. Heart rate had a weak, positive association with treatment time. The VAS gave a higher pain score for the plastic (30.8) than for the metal insert (24.4), but this difference was not statistically significant (P = 0.055). Following pain-provoking stimuli at the 2-week follow-up visit, quadrants debrided with the metal insert (31.3) scored significantly lower (less pain) (P < 0.01) on the VAS than quadrants treated with the plastic insert (30.7). It is concluded that the sonic metal insert caused less pain and discomfort to the patients due to its superior accessibility and water spray cooling. The significant difference between metal and plastic tip debrided quadrants at the follow-up visit was probably caused by the smearing effect of the metal insert with partial closure of the dentin tubule orifices.


Asunto(s)
Raspado Dental/instrumentación , Sensibilidad de la Dentina/prevención & control , Adulto , Anciano , Análisis de Varianza , Presión Sanguínea , Raspado Dental/métodos , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Metales , Persona de Mediana Edad , Dimensión del Dolor , Plásticos , Aplanamiento de la Raíz/instrumentación , Aplanamiento de la Raíz/métodos , Método Simple Ciego , Sonido
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA