RESUMEN

A fluorescent liquid pyrene derivative with a high fluorescence quantum yield (65%) in the bulk state is reported. With this as the sole oil phase, stable luminescent oil-in-water microemulsions have been prepared. Increasing the loading of liquid pyrene swells the droplets, as detected by small-angle neutron scattering. These larger droplets have a greater proportion of pyrene excimer emission contribution in their photoluminescence spectra, which leads to a red shift in the chromaticity of the emission.

RESUMEN

BACKGROUND: To develop latent classes of exposure to traumatic experiences before the age of 13 years in an urban community sample and to use these latent classes to predict the development of negative behavioral outcomes in adolescence and young adulthood. METHOD: A total of 1815 participants in an epidemiologically based, randomized field trial as children completed comprehensive psychiatric assessments as young adults. Reported experiences of nine traumatic experiences before age 13 years were used in a latent class analysis to create latent profiles of traumatic experiences. Latent classes were used to predict psychiatric outcomes at age ⩾13 years, criminal convictions, physical health problems and traumatic experiences reported in young adulthood. RESULTS: Three latent classes of childhood traumatic experiences were supported by the data. One class (8% of sample), primarily female, was characterized by experiences of sexual assault and reported significantly higher rates of a range of psychiatric outcomes by young adulthood. Another class (8%), primarily male, was characterized by experiences of violence exposure and reported higher levels of antisocial personality disorder and post-traumatic stress. The final class (84%) reported low levels of childhood traumatic experiences. Parental psychopathology was related to membership in the sexual assault group. CONCLUSIONS: Classes of childhood traumatic experiences predict specific psychiatric and behavioral outcomes in adolescence and young adulthood. The long-term adverse effects of childhood traumas are primarily concentrated in victims of sexual and non-sexual violence. Gender emerged as a key covariate in the classes of trauma exposure and outcomes.

Asunto(s)

Adultos Sobrevivientes de Eventos Adversos Infantiles/estadística & datos numéricos , Maltrato a los Niños/estadística & datos numéricos , Conducta Criminal , Estado de Salud , Trastornos Mentales/epidemiología , Trauma Psicológico/epidemiología , Suicidio/estadística & datos numéricos , Adolescente , Adulto , Adultos Sobrevivientes del Maltrato a los Niños/estadística & datos numéricos , Trastorno de Personalidad Antisocial/epidemiología , Trastorno de Personalidad Antisocial/etiología , Femenino , Humanos , Masculino , Trastornos Mentales/etiología , Trauma Psicológico/complicaciones , Adulto Joven

RESUMEN

Hotspot lavas erupted at ocean islands exhibit tremendous isotopic variability, indicating that there are numerous mantle components hosted in upwelling mantle plumes that generate volcanism at hotspots like Hawaii and Samoa. However, it is not known how the surface expression of the various geochemical components observed in hotspot volcanoes relates to their spatial distribution within the plume. Here we present a relationship between He and Pb isotopes in Samoan lavas that places severe constraints on the distribution of geochemical species within the plume. The Pb-isotopic compositions of the Samoan lavas reveal several distinct geochemical groups, each corresponding to a different geographic lineament of volcanoes. Each group has a signature associated with one of four mantle endmembers with low (3)He/(4)He: EMII (enriched mantle 2), EMI (enriched mantle 1), HIMU (high µ = (238)U/(204)Pb) and DM (depleted mantle). Critically, these four geochemical groups trend towards a common region of Pb-isotopic space with high (3)He/(4)He. This observation is consistent with several low-(3)He/(4)He components in the plume mixing with a common high-(3)He/(4)He component, but not mixing much with each other. The mixing relationships inferred from the new He and Pb isotopic data provide the clearest picture yet of the geochemical geometry of a mantle plume, and are best explained by a high-(3)He/(4)He plume matrix that hosts, and mixes with, several distinct low-(3)He/(4)He components.

RESUMEN

OBJECTIVE: To test the hypothesis that an acute increase in plasma homocysteine produced by methionine is associated with an acute increase in pulse wave velocity. DESIGN: A double blind, cross over, placebo controlled design was used and pulse wave velocity, plasma homocysteine, total cholesterol: high density lipoprotein ratio, plasma triglyceride, oxidised low density lipoprotein cholesterol concentrations, apolipoproteins A1 and B, and C reactive protein were measured between 12.5 and 20 hours after methionine loading or placebo. RESULTS: Between 12.5 and 20 hours after exposure to a methionine loading test, arterial pulse wave velocity showed no significant difference compared with placebo. At 12 hours after exposure to the methionine loading test, in the presence of a controlled diet, triglyceride concentration significantly increased by 32.6% (p<0.02), cholesterol: high density lipoprotein ratio increased significantly by 22.5% (p<0.05) compared with placebo. Simultaneously, systolic blood pressure increased significantly by 4.9% (p<0.02). CONCLUSION: In elderly volunteers, acute hyperhomocysteinaemia induced by methionine loading resulted in no overall significant delayed reduction in peripheral arterial distensibility. A significant deterioration in the lipid profile and increased blood pressure was seen during acute hyperhomocysteinaemia.

Asunto(s)

Homocisteína/metabolismo , Metionina/farmacología , Anciano , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Proteína C-Reactiva/metabolismo , Adaptabilidad , Estudios Cruzados , Método Doble Ciego , Interacciones Farmacológicas , Humanos , Lípidos/sangre , Persona de Mediana Edad , Flujo Pulsátil/efectos de los fármacos , Flujo Pulsátil/fisiología

RESUMEN

We have revisited the direct analysis experiments reported by Tomer and co-workers in the MALDI-TOFMS analysis of phosphopeptide-loaded immobilized metal ion affinity chromatography (IMAC) beads (Zhou, W.; Merrick, B. A.; Khaledi, M. G.; Tomer, K. B. J. Am. Soc. Mass Spectrom. 2000, 11, 273-282). The results described herein provide no evidence to support a laser-induced direct desorption of phosphopeptides chelated on IMAC beads. However, we have established that solubilization of mono-phosphopeptides from their immobilized Fe3+-NTA chelates does occur effectively in solutions containing certain MALDI matrices. Particularly effective is 2,5-dihydroxybenzoic acid (2,5-DHB), which apparently forms a stronger chelation complex with Fe3+-NTA than mono-phosphopeptides. With regard to the disparity observed between the low pH value of MALDI matrices (saturated 2,5-DHB(aq) approximately pH 2) and the high pH values of conventional IMAC eluents (typically above pH 7), we have also investigated the influence of eluent pH on the recovery of phosphopeptides from IMAC media. Finally, we have confirmed the importance of employing ammonium dihydrogen phosphate as buffer to achieve effective liberation of mono- and all poly-phosphopeptide species from Fe3+-NTA IMAC resin.

Asunto(s)

Metales , Fosfopéptidos/análisis , Secuencia de Aminoácidos , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Hierro , Datos de Secuencia Molecular , Reproducibilidad de los Resultados , Solubilidad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción

RESUMEN

AIMS: To investigate prescribing patterns to prevent steroid induced osteoporosis. To compare prophylactic prescribing with National Osteoporosis Society (NOS) guidelines. METHOD: All patients (n=92) taking oral corticosteroids admitted to general medical wards at a district general hospital were prospectively investigated over a nine month period. RESULTS: Variations from recommended management were revealed. Altogether 64.7% of all inpatients who qualified for prophylaxis for steroid induced osteoporosis were not provided with any suitable agent. It was also found that 21.6% of those who qualified for treatment received a bisphosphonate, the only treatment currently licensed for preventing steroid induced osteoporosis. Of those prescribed prophylactic treatment, a bisphosphonate was selected for 39.3%, hormone replacement therapy was given to 25.0%, and 35.7% received treatment that is not recommended in NOS guidelines. CONCLUSION: This study revealed substantial variations from NOS guidelines. It is suggested that osteoporosis prophylaxis during steroid treatment is promoted by local hospital guidelines, hospital and community pharmacists, audit, and general practitioners.

Asunto(s)

Glucocorticoides/efectos adversos , Osteoporosis/inducido químicamente , Prednisolona/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Difosfonatos/uso terapéutico , Femenino , Terapia de Reemplazo de Hormonas/métodos , Hospitalización , Humanos , Masculino , Persona de Mediana Edad , Osteoporosis/prevención & control , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina , Estudios Prospectivos

RESUMEN

Spontaneous life threatening haemopneumothorax is an unusual but treatable cause of unexpected circulatory collapse in young patients. Two case histories are presented to illustrate the management of this condition. Diagnosis and initial management depends on early recognition of the clinical pattern by accident and emergency (A&E) staff and/or hospital physicians. Problems may arise for two reasons. Firstly, as the incidence of life threatening spontaneous haemopneumothorax is low, admitting medical staff may not have experienced this condition in the absence of trauma. Secondly, unlike surgeons, staff in these specialties are unlikely to have received training of either traumatic or spontaneous haemopneumothorax. The cases illustrate potential problems. Not only early recognition of the clinical pattern but also proactive intervention in the A&E department are necessary before referral to a cardiothoracic surgeon. Furthermore, we suggest treatment would be improved by the introduction of management guidelines.

Asunto(s)

Hemoneumotórax/diagnóstico , Hemoneumotórax/terapia , Adulto , Servicios Médicos de Urgencia , Hemoneumotórax/diagnóstico por imagen , Hemoneumotórax/cirugía , Humanos , Masculino , Guías de Práctica Clínica como Asunto , Radiografía

Asunto(s)

Arteriopatías Oclusivas/etiología , Paro Cardíaco/etiología , Quiste Mediastínico/complicaciones , Arteria Pulmonar , Enfermedad Aguda , Adulto , Arteriopatías Oclusivas/epidemiología , Resultado Fatal , Femenino , Paro Cardíaco/epidemiología , Humanos , Quiste Mediastínico/epidemiología

RESUMEN

To investigate the accuracy of clinical severity assessment of asthmatics and to compare emergency and subsequent ward management with British Thoracic Society (BTS) Guidelines, the records of all patients admitted for severe asthma (46) over a 5-month period to a District General Hospital were inspected. Variations from recommended management were revealed. Appropriate oxygen administration was often not provided in casually and patients frequently left hospital before their discharge criteria were attained: recommended diurnal variations in peak flow were exceeded in 26%. Eleven per cent of discharges were against medical advice, making provision of adequate management logistically difficult. Adherence to BTS guidelines on the need for arterial blood gas (ABG) analysis would have led to a failure to detect significant hypoxaemia in 25% of cases. This study identified substantial variations from BTS management guidelines. It is suggested that oximetry is necessary on arrival to guide selection for arterial blood gas analysis.

Asunto(s)

Asma/diagnóstico , Asma/terapia , Tratamiento de Urgencia , Enfermedad Aguda , Análisis de los Gases de la Sangre , Femenino , Hospitales de Distrito , Hospitales Generales , Humanos , Masculino , Guías de Práctica Clínica como Asunto , Sociedades Médicas , Reino Unido

RESUMEN

Resistance to the intracellular Ca2+ pump inhibitor thapsigargin (TG) is associated with overexpression of both Ca2+ transport ATPase and the multidrug resistance (mdr) transporter P-glycoprotein (pgp). This is supported by increased resistance to TG following transfection of a functional pgp1 cDNA, and reversal of TG resistance with known inhibitors of pgp function. However, pgp is unlikely to represent the only mechanism of resistance to TG. Cell lines selected for high levels of resistance to TG (250-fold) show only a 3.7-fold increase in pgp expression and a 2-fold increase in cross-resistance to other drugs of the mdr class. Overexpression of endogenous Ca2+ transport ATPase may represent a second mechanism of resistance to TG. Increased Ca2+ ATPase expression (3-fold) is seen in cells made resistant to TG, and TG resistance increases with the transfection of a specific Ca2+ ATPase cDNA into DC-3F cells. If these transfectants are then made resistant to TG, both the endogenous Ca2+ ATPase and the exogenously transfected Ca2+ ATPase become overexpressed. These studies suggest that while TG may be a substrate for pgp, acquired resistance to TG can involve alterations in both pgp and Ca2+ ATPase expression. Additional, as yet unidentified, mechanisms of resistance may be involved in resistance to TG.

Asunto(s)

ATPasas Transportadoras de Calcio/biosíntesis , Proteínas Portadoras/biosíntesis , Resistencia a Medicamentos , Expresión Génica , Glicoproteínas de Membrana/biosíntesis , Mitotano/farmacología , Terpenos/toxicidad , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP , Animales , Azidas/metabolismo , ATPasas Transportadoras de Calcio/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , División Celular , Línea Celular , Supervivencia Celular/efectos de los fármacos , Colchicina/toxicidad , Cricetinae , Cricetulus , ADN Complementario/metabolismo , Dactinomicina/toxicidad , Daunorrubicina/toxicidad , Dihidropiridinas/metabolismo , Pulmón , Glicoproteínas de Membrana/metabolismo , Familia de Multigenes , Especificidad por Sustrato , Terpenos/metabolismo , Tapsigargina , Transfección , Vincristina/toxicidad

RESUMEN

Many basalts from oceanic islands, ridges, and arcs show strong trace element evidence for melting at great depths, where garnet is a stable phase in mantle peridotites. If partial melts ascend to the surface by porous (intergranular) flow processes, the high-pressure garnet signature will be obliterated by diffusive reequilibration at shallower depths in the mantle. Spiegelman and Kenyon [Spiegelman, M. & Kenyon, P. (1992) Earth Planet Sci. Lett. 109, 611-620] argued that partial melts must therefore be focused into a coarser transport network, for high-speed delivery to the surface. Numerous natural network systems, such as rivers and the human vascular and bronchial systems, have fractal structures that are optimal for minimizing energy expenditure during material transport. I show here that a fractal magma "tree" with these optimal properties provides a network in which magma rapidly loses diffusive chemical "contact" with its host matrix. In this fractal network, magma conduits combine by twos, with the radius and flow velocities scaling as (2)n/3, where n is the generation number. For reasonable values of volume diffusivities, viscosities, and aspect ratios, melts will experience only limited diffusive reequilibration once they have traveled some hundreds of meters from their source. Melts thus represent rather local mantle domains, and there is little problem in delivering melts with deep (<100 km) geochemical signatures to the surface.

RESUMEN

The (87)Sr/(86)Sr ratios in some bulk abyssal and alpine peridotites are too high to be binary mixtures of depleted mantle and seawater components. The apparent excess, or "orphan," (87)Sr appears to be separated from its radioactive parent. Such observations were widely held to be analytical artifacts. Study of several occurrences of orphan (87)Sr shows that the orphan component in abyssal peridotite is located in the alteration products of olivine and enstatite in the peridotite. The orphan (87)Sr is most likely introduced by infiltration of low-temperature (<200 degrees C) seawater bearing suspended detrital particulates. These particulates include grains of detrital clay that are partly derived from continental (that is, granitic) sources and thus are highly radiogenic. Orphan (87)Sr and other radiogenic isotopes may provide a tracer for low-temperature seawater penetrating into the oceanic crust.

RESUMEN

Many oceanic island basalts show sublinear subparallel arrays in Sr-Nd-Pb isotopic space. The depleted upper mantle is rarely a mixing end-member of these arrays, as would be expected if mantle plumes originated at a 670-kilometer boundary layer and entrained upper mantle during ascent. Instead, the arrays are fan-shaped and appear to converge on a volume in isotopic space characterized by low (87)Sr/(86)Sr and high (143)Nd/(144)Nd, (206)Pb/(204)Pb, and (3)He/(4)He ratios. This new isotopic component may be the lower mantle, entrained into plumes originating from the core-mantle boundary layer.

RESUMEN

We show that the rubidium in amphiboles is generally depleted with respect to potassium. The K:Rb ratios of 50 analyzed amphiboles range from 100 to 5000, averaging 1120. This fractionation effect holds for potassium concentrations ranging from 0.05 to 1.5 percent. The K:Rb ratios of abyssal tholeiites do not place unambiguous limits on the K:Rb ratio of the upper mantle, since partial melting of a mantle material such as amphibole peridotite would produce a liquid with a K:Rb ratio higher than that in the initial material. Large-scale mineralogic control of distributions of trace elements in the mantle could produce trends with depth that are the reverse of trends normally attributed to differentiation processes.