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The development of high-fidelity mechanical property prediction models for the design of polycrystalline materials relies on large volumes of microstructural feature data. Concurrently, at these same scales, the deformation fields that develop during mechanical loading can be highly heterogeneous. Spatially correlated measurements of 3D microstructure and the ensuing deformation fields at the micro-scale would provide highly valuable insight into the relationship between microstructure and macroscopic mechanical response. They would also provide direct validation for numerical simulations that can guide and speed up the design of new materials and microstructures. However, to date, such data have been rare. Here, a one-of-a-kind, multi-modal dataset is presented that combines recent state-of-the-art experimental developments in 3D tomography and high-resolution deformation field measurements.
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AIMS: The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties. METHODS AND RESULTS: Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5.8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 + or - 0.2 degrees C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5 degrees C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG). CONCLUSIONS: Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes.
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ADN de Hongos/genética , ADN Ribosómico/genética , Metarhizium/genética , Metarhizium/metabolismo , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados/métodos , Frío , Calor , Metarhizium/clasificación , Metarhizium/aislamiento & purificación , Análisis de Secuencia de ADN/métodos , Especificidad de la EspecieRESUMEN
AIMS: The genetic diversity of Beauveria bassiana was investigated by comparing isolates of this species to each other (49 from different geographical regions of Brazil and 4 from USA) and to other Beauveria spp. METHODS AND RESULTS: The isolates were examined by multilocus enzyme electrophoresis (MLEE), amplified fragment length polymorphism (AFLP), and rDNA sequencing. MLEE and AFLP revealed considerable genetic variability among B. bassiana isolates. Several isolates from South and Southeast Brazil had high similarity coefficients, providing evidence of at least one population with clonal structure. There were clear genomic differences between most Brazilian and USA B. bassiana isolates. A Mantel test using data generated by AFLP provided evidence that greater geographical distances were associated with higher genetic distances. AFLP and rDNA sequencing demonstrated notable genotypic variation between B. bassiana and other Beauveria spp. CONCLUSION: Geographical distance between populations apparently is an important factor influencing genotypic variability among B. bassiana populations in Brazil. SIGNIFICANCE AND IMPACT OF THE STUDY: This study characterized many B. bassiana isolates. The results indicate that certain Brazilian isolates are considerably different from others and possibly should be regarded as separate species from B. bassiana sensu latu. The information on genetic variation among the Brazilian isolates, therefore, will be important to comprehending the population structure of B. bassiana in Brazil.
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Hypocreales/genética , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Brasil , ADN de Hongos/genética , ADN Ribosómico/genética , Electroforesis/métodos , Variación Genética , Genotipo , Geografía , Hypocreales/enzimología , Análisis de Secuencia de ADN , Estados UnidosRESUMEN
BACKGROUND/OBJECTIVES: Consumption of hydroxypropylmethylcellulose (HPMC), a viscous dietary fiber, lowers total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). However, HPMC had not previously been studied in individuals receiving lipid drug therapy. SUBJECTS/METHODS: This randomized, double-blind crossover trial examined the lipid effects of HPMC in subjects with hypercholesterolemia on statin therapy. Men (n=5) and women (n=8) with LDL-C> or =2.59 mmol/l after at least 4 weeks of stable-dose statin therapy, and a mean age of 58.6 years, were enrolled. Subjects received twice daily doses of either 2.5 g HPMC or control, delivered in a lemonade beverage for 4 weeks, then crossed over to receive the opposite treatment for an additional 4 weeks. RESULTS: Mean baseline concentrations of TC, non-high-density lipoprotein cholesterol (non-HDL-C), LDL-C, HDL-C, triglyceride (TG), TC/HDL-C ratio and apolipoprotein (Apo) B were 4.95, 3.63, 3.03, 1.33, 1.30 and 3.89 mmol/l and 1.00 g/l, respectively. HPMC consumption resulted in significantly larger reductions (P<0.01 vs control for all) in TC (-10.9 vs -3.5%), non-HDL-C (-12.8 vs -2.9%), LDL-C (-15.7 vs -5.1%), TC/HDL-C ratio (-5.3 vs +1.3%) and Apo B (-8.7 vs -3.9%). There were no differences between treatments for changes in HDL-C (-5.2 vs -4.3%) or TG (+3.9 vs +8.9%). CONCLUSIONS: These results support the view that HPMC is an effective adjunct to statin therapy for further lowering atherogenic lipids and lipoproteins in men and women with primary hypercholesterolemia.
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Anticolesterolemiantes/uso terapéutico , Apolipoproteínas B/sangre , Colesterol/sangre , Hipercolesterolemia/tratamiento farmacológico , Metilcelulosa/análogos & derivados , Anticolesterolemiantes/farmacología , Estudios Cruzados , Método Doble Ciego , Quimioterapia Combinada , Femenino , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Derivados de la Hipromelosa , Masculino , Metilcelulosa/farmacología , Metilcelulosa/uso terapéutico , Persona de Mediana EdadRESUMEN
The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snake River drainage and the Bonneville Basin. This boundary has not previously been recognized in Utah suckers based on morphologic variation, but has been recently described in two endemic cyprinids in the region. Populations in valleys east of the Wasatch Mountains in Utah clustered with the Snake River populations, suggesting that these valleys may have had an ancient hydrologic connection to the Snake River. We also found evidence of population isolation within the Bonneville Basin, corresponding to two Pleistocene sub-basins of the ancient Lake Bonneville. In contrast, we found no molecular evidence for deep divergence between Utah suckers and June suckers in Utah Lake or for a history of hybridization between divergent lineages in that population, although we recognize that demographic events may have obscured this signal. These findings suggest that the morphological differences between Utah and June suckers in Utah Lake may be the result of strong, and relatively recent, ecological selection. In summary, morphological and molecular characters seem to vary along different axes in different portions of the range of this taxon, providing an interesting system for studying the contributions of neutral and adaptive variation to species diversity.
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Cipriniformes/genética , Genética de Población , Animales , ADN Mitocondrial , Marcadores Genéticos , Variación Genética , Hibridación Genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Análisis de Secuencia de ADN , UtahRESUMEN
Populations of the freshwater mussel genus Anodonta appear to be in a state of rapid decline in western North America, following a trend that unfortunately seems to be prevalent among these animals (Mollusca: Unionoida). Here we describe the patterns of molecular divergence and diversity among Anodonta populations in the Bonneville Basin, a large sub-basin of the Great Basin in western North America. Using amplified fragment length polymorphism (AFLP) analysis, we found a striking lack of nuclear diversity within some of these populations, along with a high degree of structuring among populations (FST = 0.61), suggesting post-Pleistocene isolation, due either to a long-term loss of hydrologic connectivity among populations or to more recent fish introductions. We also found evidence of recent hybridization in one of these populations, possibly mediated by fish-stocking practices. Using mitochondrial sequence data, we compared the Bonneville Basin populations to Anodonta in several other drainages in western North America. We found a general lack of resolution in these phylogenetic reconstructions, although there was a tendency for the Bonneville Basin Anodonta (tentatively A. californiensis) to cluster with A. oregonensis from the adjacent Lahontan Basin in Nevada. We recommend further investigation of anthropogenic factors that may be contributing to the decline of western Anodonta and a broad-scale analysis and synthesis of genetic and morphological variation among Anodonta in western North America.
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Bivalvos/genética , Evolución Molecular , Variación Genética , Genética de Población , Filogenia , Animales , Secuencia de Bases , ADN Mitocondrial/genética , Agua Dulce , Geografía , Haplotipos/genética , Hibridación Genética/genética , Funciones de Verosimilitud , Modelos Genéticos , Datos de Secuencia Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Análisis de Secuencia de ADN , UtahRESUMEN
A wide variety of functional domains exist within human genes. Since different domains vary in their roles regarding overall gene function, the ability for a mutation in a gene region to produce disease varies among domains. We tested two hypotheses regarding distributions of mutations among functional domains by using (1) sets of single nucleotide disease mutations for six genes (CFTR, TSC2, G6PD, PAX6, RS1, and PAH) and (2) sets of polymorphic replacement and silent mutations found in two genes (CFTR and TSC2). First, we tested the null hypothesis that sets of mutations are uniformly distributed among functional domains within genes. Second, we tested the null hypothesis that disease mutations are distributed among gene regions according to expectations derived from the distribution of evolutionary conserved and variable amino acid sites throughout each gene. In contrast to the mainly uniform distribution of sets of silent and polymorphic mutations, sets of disease mutations generally rejected the null hypotheses of both uniform and evolutionary-influenced distributions. Although the disease mutation data showed a better agreement with the evolutionary-derived expectations, disease mutations were found to be statistically overabundant in conserved domains, and under-represented in variable regions, even after accounting for amino acid site variability of domains over long-term evolutionary history. This finding suggests that there is a non-additive influence of amino acid site conservation on the observed intragenic distribution of disease mutations, and underscores the importance of understanding the patterns of neutral amino acid substitutions permitted in a gene over long-term evolutionary history.
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Evolución Molecular , Enfermedades Genéticas Congénitas/genética , Mutación/genética , Polimorfismo de Nucleótido Simple/genética , Estructura Terciaria de Proteína/genética , Secuencia Conservada/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Bases de Datos Genéticas , Proteínas del Ojo/genética , Glucosafosfato Deshidrogenasa/genética , Proteínas de Homeodominio/genética , Humanos , Proteína 1 de Transporte de Anión Orgánico/genética , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box , Filogenia , Proteínas Represoras/genética , Proteína 2 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de TumorRESUMEN
Measurement of tumour and normal tissue perfusion in vivo in cancer patients will aid the clinical development of antiangiogenic and antivascular agents. We investigated the potential antiangiogenic effects of the drug razoxane by measuring the changes in parameters estimated from H(2)(15)O and C(15)O positron emission tomography (PET) to indicate alterations in vascular physiology. The study comprised 12 patients with primary or metastatic renal tumours >3 cm in diameter enrolled in a Phase II clinical trial of oral razoxane. Perfusion, fractional volume of distribution of water (VD) and blood volume (BV) were measured in tumour and normal tissue before and 4-8 weeks after treatment with 125 mg twice-daily razoxane. Renal tumour perfusion was variable but lower than normal tissue: mean 0.87 ml min(-1) ml(-1) (range 0.33-1.67) compared to renal parenchyma: mean 1.65 ml min(-1) ml(-1) (range 1.16-2.88). In eight patients, where parallel measurements were made during the same scan session, renal tumour perfusion was significantly lower than in normal kidney (P=0.0027). There was no statistically significant relationship between pretreatment perfusion and tumour size (r=0.32, n=13). In six patients scanned before and after razoxane administration, there was no statistically significant change in tumour perfusion: mean perfusion pretreatment was 0.81 ml min(-1) ml(-1) (range 0.46-1.26) and perfusion post-treatment was 0.72 ml min(-1) ml(-1) (range 0.51-1.15, P=0.15). Tumour VD and BV did not change significantly following treatment: mean pretreatment VD=0.66 (range 0.50-0.87), post-treatment VD=0.71 (range 0.63-0.82, P=0.22); pretreatment BV=0.18 ml ml(-1) (range 0.10-0.25), post-treatment BV=0.167 ml ml(-1) (range 0.091-0.24, P=0.55). Tumour perfusion, VD and BV did not change significantly with tumour progression. This study has shown that H(2)(15)O and C(15)O PET provide useful in vivo physiological measurements, that even highly angiogenic renal cancers have poor perfusion compared to surrounding normal tissue, and that PET can provide valuable information on the in vivo biology of angiogenesis in man and can assess the effects of antiangiogenic therapy.
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Antineoplásicos/farmacología , Antineoplásicos/farmacocinética , Carcinoma de Células Renales/irrigación sanguínea , Carcinoma de Células Renales/tratamiento farmacológico , Neoplasias Renales/irrigación sanguínea , Neoplasias Renales/tratamiento farmacológico , Neovascularización Patológica , Razoxano/farmacología , Razoxano/farmacocinética , Tomografía Computarizada de Emisión , Antineoplásicos/administración & dosificación , Monóxido de Carbono , Carcinoma de Células Renales/diagnóstico por imagen , Humanos , Neoplasias Renales/diagnóstico por imagen , Radioisótopos de Oxígeno , Razoxano/administración & dosificación , Flujo Sanguíneo Regional , AguaRESUMEN
Data on replacement mutations in genes of disease patients exist in a variety of online resources. In addition, genome sequencing projects and individual gene sequencing efforts have led to the identification of disease gene homologs in diverse metazoan species. The availability of these two types of information provides unique opportunities to investigate factors that are important in the development of genetically based disease by contrasting long and short-term molecular evolutionary patterns. Therefore, we conducted an analysis of disease-associated human genetic variation for seven disease genes: the cystic fibrosis transmembrane conductance regulator, glucose-6-phosphate dehydrogenase, the neural cell adhesion molecule L1, phenylalanine hydroxylase, paired box 6, the X-linked retinoschisis gene and TSC2/tuberin. Our analyses indicate that disease mutations show definite patterns when examined from an evolutionary perspective. Human replacement mutations resulting in disease are overabundant at amino acid positions most conserved throughout the long-term history of metazoans. In contrast, human polymorphic replacement mutations and silent mutations are randomly distributed across sites with respect to the level of conservation of amino acid sites within genes. Furthermore, disease-causing amino acid changes are of types usually not observed among species. Using Grantham's chemical difference matrix, we find that amino acid changes observed in disease patients are far more radical than the variation found among species and in non-diseased humans. Overall, our results demonstrate the usefulness of evolutionary analyses for understanding patterns of human disease mutations and underscore the biomedical significance of sequence data currently being generated from various model organism genome sequencing projects.
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Evolución Molecular , Predisposición Genética a la Enfermedad/genética , Aminoácidos/genética , Animales , Bovinos , Cricetinae , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Bases de Datos de Ácidos Nucleicos , Proteínas del Ojo/genética , Frecuencia de los Genes , Variación Genética , Glucosafosfato Deshidrogenasa/genética , Proteínas de Homeodominio/genética , Humanos , Complejo de Antígeno L1 de Leucocito , Glicoproteínas de Membrana/genética , Ratones , Mutación , Moléculas de Adhesión de Célula Nerviosa/genética , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box , Fenilalanina Hidroxilasa/genética , Filogenia , Polimorfismo de Nucleótido Simple , Ratas , Proteínas Represoras/genética , Especificidad de la Especie , Proteína 2 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de TumorRESUMEN
This article examines the use of the Tar Wars curriculum with the public health problem of preteen smoking and outlines interventions with a middle school population by community health student nurses from a state university. Smoking is the single most preventable cause of death and disability. Three million people die worldwide each year as a result of smoking. Cigarette smoking has now been labeled a pediatric disease. Estimates are that 3,000 children will begin a lifelong addiction to cigarettes every day. They will face a life of poor quality based on the medical consequences of smoking cigarettes. Mortality from tobacco use is annually greater than that from drug abuse, AIDS, suicide, homicide, and motor vehicle accidents combined. Preteen and teenage smoking is now a public health problem, therefore implications for service learning, nursing advocacy, and interventions with this health problem are discussed.
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Conducta del Adolescente , Conductas Relacionadas con la Salud , Servicios de Enfermería Escolar , Prevención del Hábito de Fumar , Adolescente , Curriculum , Humanos , Masculino , Evaluación de Programas y Proyectos de Salud , Fumar/psicología , South Carolina , Estudiantes de EnfermeríaRESUMEN
Iron chelators are pluripotent neuronal antiapoptotic agents that have been shown to enhance metabolic recovery in cerebral ischemia models. The precise mechanism(s) by which these agents exert their effects remains unclear. Recent studies have demonstrated that iron chelators activate a hypoxia signal transduction pathway in non-neuronal cells that culminates in the stabilization of the transcriptional activator hypoxia-inducible factor-1 (HIF-1) and increased expression of gene products that mediate hypoxic adaptation. We examined the hypothesis that iron chelators prevent oxidative stress-induced death in cortical neuronal cultures by inducing expression of HIF-1 and its target genes. We report that the structurally distinct iron chelators deferoxamine mesylate and mimosine prevent apoptosis induced by glutathione depletion and oxidative stress in embryonic cortical neuronal cultures. The protective effects of iron chelators are correlated with their ability to enhance DNA binding of HIF-1 and activating transcription factor 1(ATF-1)/cAMP response element-binding protein (CREB) to the hypoxia response element in cortical cultures and the H19-7 hippocampal neuronal cell line. We show that mRNA, protein, and/or activity levels for genes whose expression is known to be regulated by HIF-1, including glycolytic enzymes, p21(waf1/cip1), and erythropoietin, are increased in cortical neuronal cultures in response to iron chelator treatment. Finally, we demonstrate that cobalt chloride, which also activates HIF-1 and ATF-1/CREB in cortical cultures, also prevents oxidative stress-induced death in these cells. Altogether, these results suggest that iron chelators exert their neuroprotective effects, in part, by activating a signal transduction pathway leading to increased expression of genes known to compensate for hypoxic or oxidative stress.
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Apoptosis/fisiología , Corteza Cerebral/citología , Corteza Cerebral/fisiología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/farmacología , Ciclinas/genética , Proteínas de Unión al ADN/metabolismo , Deferoxamina/farmacología , Eritropoyetina/genética , Regulación de la Expresión Génica , Neuronas/citología , Neuronas/fisiología , Proteínas Nucleares/metabolismo , Estrés Oxidativo/fisiología , Factores de Transcripción/metabolismo , Factor de Transcripción Activador 1 , Animales , Apoptosis/efectos de los fármacos , Células Cultivadas , Quelantes/farmacología , Cobalto/farmacología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Inducción Enzimática/efectos de los fármacos , Feto , Fructosa-Bifosfato Aldolasa/biosíntesis , Fructosa-Bifosfato Aldolasa/genética , Regulación de la Expresión Génica/efectos de los fármacos , Glutatión/metabolismo , Glucólisis , Factor 1 Inducible por Hipoxia , Subunidad alfa del Factor 1 Inducible por Hipoxia , L-Lactato Deshidrogenasa/biosíntesis , L-Lactato Deshidrogenasa/genética , Mimosina/farmacología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores , Ratas , Ratas Sprague-DawleyRESUMEN
In positron emission tomography (PET), random coincidence events must be removed from the measured signal in order to obtain quantitatively accurate data. The most widely implemented technique for estimating the number of random coincidences on a particular line of response is the delayed coincidence channel method. Estimates obtained in this way are subject to Poisson noise, which then propagates into the final image when the estimates are subtracted from the prompt signal. However, this noise may be reduced if variance reduction techniques similar to those used in normalization of PET detectors are applied to the randoms estimates prior to use. We have investigated the effects of randoms variance reduction on noise-equivalent count (NEC) rates on a whole-body PET camera operating in 3D mode. NEC rates were calculated using a range of phantoms representative of situations that might be encountered clinically. We have also investigated the properties of three randoms variance reduction methods (based on algorithms previously used for normalization) in terms of their systematic accuracy and their variance reduction efficacy, both in phantom studies and in vivo. Those algorithms investigated that do not make assumptions about the spatial distribution of random coincidences give the best estimates of the randoms distribution. With the camera used, which has a limited axial extent (10.8 cm) and a large ring diameter (102 cm), the gains in image signal-to-noise ratio obtained with this technique ranged from approximately 5% to approximately 15%, depending on object size, activity distribution and the amount of activity in the field of view. Larger gains would be expected if this technique were to be employed on cameras of greater axial extent and smaller ring diameter.
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Tomografía Computarizada de Emisión/instrumentación , Tomografía Computarizada de Emisión/métodos , Algoritmos , Modelos Estadísticos , Fantasmas de ImagenRESUMEN
The aim of this paper is to report on experience with 3D positron emission tomography (PET) in our institute where we have three 3D scanners, of which two operate exclusively in 3D mode (ECAT ART, EXACT 3D). Fully 3D PET requires attention to a number of factors which are not as problematic in 2D PET. Firstly, 3D tomographs designed for whole-body acquisition suffer from a large single-photon field of view, extending well beyond the coincidence field of view. Single photons from outside the coincidence field of view increase the dead time and random coincidence rates, and contribute scattered events. For brain studies, we have extended the lead side shielding at the ends of the tomograph to mitigate against these effects, and this has dramatically improved the count rate performance. This approach is not as effective for whole-body scanning. In addition, operating in 3D without septa necessitates new approaches to transmission scanning, as measurements using positron emitters such as 68Ge/68Ga have the unfavourable characteristics of high dead time and high scatter. Both of our fully 3D scanners use 137Cs for single-photon transmission measurements, although the data are treated differently. On the ECAT ART, a combination of physical and electronic collimation effectively reduces transmission scatter to acceptable levels. On the EXACT 3D physical collimation is not as readily implemented and therefore segmentation and reassignment of the histogrammed attenuation (mu) values is employed to produce unbiased attenuation correction factors in 3D. Many of the lessons learnt with these BGO (bismuth germanate) based tomographs will be applicable to the next generation of systems using faster detectors such as lutetium oxyorthosilicate (LSO).
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Encéfalo/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía Computarizada de Emisión/instrumentación , Tomografía Computarizada de Emisión/métodos , Radioisótopos de Cesio , Diseño de Equipo , Radioisótopos de Galio , Germanio , Humanos , Plomo , Fotones , Protección Radiológica , Radioisótopos , Sensibilidad y Especificidad , Tomografía Computarizada de Emisión de Fotón Único/instrumentaciónRESUMEN
The ECAT EXACT3D (CTI/Siemens 966) 3D-only PET tomograph has unprecedented sensitivity due to the large BGO (bismuth germanate) detector volume. However, the consequences of a large (23.4 cm) axial field-of-view (FOV) and the need for a patient port diameter to accommodate body scanning make the device more sensitive to photons arising from activity outside the direct (coincidence) FOV. This leads to relatively higher deadtime and an increased registration of random and scatter (true) coincidences. The purpose of this study is to determine the influence of activity outside the FOV on (i) noise-equivalent counts (NEC) and (ii) the performance of a 'model-based' scatter correction algorithm, and to investigate the effect of side shielding additional to that supplied with the tomograph. Annular shielding designed for brain scanning increased the NEC for blood flow (H[2]15O) measurement (integrated over 120 s) by up to 25%. For 11C tracer studies, the increase is less than 5% over 120 min. Purpose-built additional body shielding, made to conform to the shape of a volunteer, reduced the randoms count rate in a heart blood flow measurement (H[2]15O) by about 30%. After scatter correction the discrepancy between ROI count ratios for compartments within the 20 cm diameter 'Utah' phantom differed by less than 5% from true (sampled) activity concentration ratios. This was so with or without activity outside the FOV and with or without additional side shielding. Count rate performance is thus improved by extra shielding but more improvement is seen in head than in body scanning. Measurement of heart blood flow using bolus injections of H(2)15O would benefit from the use of detectors with lower deadtime and superior timing resolution such as LSO (lutetium oxyorthosilicate).
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Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Tomografía Computarizada de Emisión/instrumentación , Tomografía Computarizada de Emisión/métodos , Algoritmos , Radioisótopos de Carbono , Diseño de Equipo , Humanos , Modelos Teóricos , Fotones , Reproducibilidad de los Resultados , Dispersión de Radiación , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: A new emphasis has been directed toward "off-pump" coronary artery bypass grafting to avoid the morbidity of cardiopulmonary bypass and further reduce the postoperative hospital length of stay. With the intent of achieving a hospital discharge for "on-pump" coronary artery bypass grafting procedures comparable with the same procedures "off pump," we applied a rapid-recovery protocol with particular attention paid to patients eligible for discharge on the third postoperative day. METHODS: The cases of 104 consecutive patients who underwent isolated coronary artery bypass grafting using cardiopulmonary bypass were retrospectively reviewed. A rapid-recovery protocol emphasizing reduced cardiopulmonary bypass time, an anesthesia protocol for early extubation, perioperative administration of corticosteroids and thyroid hormone, and aggressive diuresis was applied to all patients. The goal during the first 24 hours postoperatively was to achieve early extubation as well as a mild state of negative fluid balance and to ensure absence of postoperative bleeding and a safe transfer from the intensive care unit to a monitored floor. On the second postoperative day, chest drains were discontinued, and aggressive ambulation therapy was instituted. If at 72 hours postoperatively the patient was walking without assistance, had return of normal bowel function, and had no atrial fibrillation, a 3-day discharge home was planned. RESULTS: The 30-day mortality rate for the entire group was 1.9%. The average postoperative hospital length of stay for the entire series was 4.8 +/- 2.4 days. Of the 102 survivors, 30 patients (29%) were discharged within 3 days postoperatively (group 1), and 72 patients (71%) were discharged after the third postoperative day (group 2). Patients in group 1 were younger and had fewer comorbid conditions. Compared with group 2, group 1 had fewer patients with diabetes (7% versus 28%; p < 0.05), congestive heart failure (7% versus 18%), symptomatic vascular disease (0% versus 11%), chronic obstructive pulmonary disease (0% versus 10%), ambulatory difficulties (0% versus 10%), and the requirement of an intraaortic balloon pump preoperatively (13% versus 35%). Group 1 patients also had almost no complications and a lower readmission rate (3.3% versus 6.9%). CONCLUSIONS: With the application of a rapid-recovery protocol to patients undergoing "on-pump" coronary artery bypass grafting, discharge home within 3 days postoperatively is attainable and safe for patients who have minimal comorbid conditions.
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Puente Cardiopulmonar , Puente de Arteria Coronaria , Tiempo de Internación , Anciano , Puente de Arteria Coronaria/mortalidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cuidados Posoperatorios , Complicaciones Posoperatorias , Estudios RetrospectivosRESUMEN
BACKGROUND: Rapid recovery protocols after coronary artery bypass grafting have been applied successfully to young patients with normal ventricular function. However, the success of such protocols when applied to the elderly population has not been thoroughly validated, and at some centers there is still reluctance in allowing elderly patients to be discharged early from the hospital. METHODS: One hundred fifty-two consecutive younger patients (< 70 years) were compared retrospectively with 167 consecutive elderly patients (> or = 70 years) who underwent isolated coronary artery bypass grafting using cardiopulmonary bypass. A rapid recovery protocol emphasizing an anesthetic protocol for early extubation, reduced cardiopulmonary bypass time, and perioperative administration of corticosteroids and thyroid hormone was applied to all patients. The protocol also emphasized early identification and management of postoperative atrial fibrillation, a proactive negative fluid balance, rapid return of bowel function, mobilization of the patient, and aggressive use of the intraaortic balloon pump preoperatively. RESULTS: The 30-day mortality rate for the younger group of patients was 3.3% (Parsonnet risk 7.2 +/- 6.2), compared with 4.2% (Parsonnet risk, 17.7 +/- 6.8) for the elderly group of patients. There were no statistically significant differences in the 30-day mortality rates or postoperative complications between the elderly and younger patient groups. Rapid recovery with discharge before the fifth postoperative day was achieved in 19% of the elderly, in comparison with 48% of the younger patients (p < 0.001). The younger patients were discharged earlier after operation than the older patients (5.7 +/- 5.2 versus 8.0 +/- 8.5 days; p < 0.01). CONCLUSIONS: Application of the rapid recovery protocol helped expedite recovery for all patients regardless of age, acuity of illness, or associated conditions. Although younger patients had a significantly shorter postoperative length of hospital stay, older patients performed well and are suitable candidates for rapid recovery protocols.
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Convalecencia , Puente de Arteria Coronaria/rehabilitación , Anciano , Antiarrítmicos/uso terapéutico , Fibrilación Atrial/tratamiento farmacológico , Fibrilación Atrial/epidemiología , Puente Cardiopulmonar , Estudios de Casos y Controles , Glicósidos Digitálicos/uso terapéutico , Femenino , Humanos , Contrapulsador Intraaórtico , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Alta del Paciente , Complicaciones Posoperatorias/tratamiento farmacológico , Complicaciones Posoperatorias/epidemiología , Procainamida/uso terapéutico , Estudios Retrospectivos , Tasa de Supervivencia , Tiroxina/uso terapéutico , Factores de Tiempo , Triyodotironina/uso terapéuticoRESUMEN
PURPOSE: Hypotony maculopathy after glaucoma filtering surgery with adjunctive mitomycin C has been reported to occur in 3% to 14% of cases. The authors evaluated its incidence when using a corneal safety-valve incisior intended to reduce its occurrence. The authors also evaluated a technique for reversing hypotony maculopathy by reoperation using two sets of stitches in the scleral flap, with one set tied tightly to temporarily raise the intraocular pressure, stretch the sclera, and flatten chorioretinal folds. METHODS: The authors reviewed the results of 699 procedures performed between April 1991 and October 1994. All were performed or supervised by one surgeon (PFP). RESULTS: Hypotony maculopathy developed in 9 (1.3%) of 699 eyes. There was a statistically significant higher incidence in primary filters (4%) as compared to secondary filters or combined procedures. After revision, eight (89%) of nine recovered visual acuity of greater than or equal to 20/30 and the mean intraocular pressure was 14.5 +/- 4 mmHg at a mean follow-up of 15 months. CONCLUSION: The incidence of hypotony maculopathy after glaucoma filtering surgery with mitomycin C using a corneal safety-valve incision is less than that reported in the literature without this incision. There is an increased risk in myopes, young patients, and primary filters. Early intervention with the described scleral flap revision technique usually allows restoration of prefiltration visual acuity without compromise of bleb function.
Asunto(s)
Cirugía Filtrante/efectos adversos , Glaucoma/cirugía , Mácula Lútea , Mitomicina/efectos adversos , Inhibidores de la Síntesis del Ácido Nucleico/efectos adversos , Hipotensión Ocular/etiología , Enfermedades de la Retina/etiología , Adulto , Anciano , Extracción de Catarata , Quimioterapia Adyuvante , Córnea/cirugía , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Presión Intraocular , Masculino , Persona de Mediana Edad , Hipotensión Ocular/fisiopatología , Hipotensión Ocular/cirugía , Enfermedades de la Retina/fisiopatología , Enfermedades de la Retina/cirugía , Factores de Riesgo , Esclerótica/cirugía , Colgajos Quirúrgicos , Agudeza VisualRESUMEN
OBJECTIVE: To identify the incidence, causative organisms, and clinical outcomes of eyes with bleb-associated endophthalmitis after glaucoma filtering procedures with adjunctive mitomycin. METHODS: Retrospective analysis of 773 consecutive eyes that underwent glaucoma filtering surgery at the Bascom Palmer Eye Institute, Miami, Fla. The course of 609 eyes from 485 patients with a minimum of 3 months of follow-up were reviewed. RESULTS: Mean follow-up was 16.0 +/- 11.5 months (range, 3-48 months). Of the 609 eyes, 13 (2.1%) developed bleb-associated endophthalmitis an average of 18.5 +/- 13.2 months after surgery (range, 1-45 months). The incidence of bleb-associated endophthalmitis was significantly greater after inferior trabeculectomy (7.8% per patient-year) than after superior trabeculectomy (1.3% per patient-year) by Kaplan-Meier estimates (P = .02, log rank test). The cumulative incidence was 13% for inferior limbal blebs and 1.6% for superior limbal blebs. Nine (69.2%) of the 13 eyes were culture positive. Streptococcus sanguis and Haemophilus influenzae (6/13 [46.2%]) were the most frequent causative organisms. The mean increase in intraocular pressure after endophthalmitis treatment was 1.2 mm Hg, with a mean decrease in visual acuity of 1.42 logMAR units. Eight (61.5%) of the 13 eyes had a final acuity of 20/400 or better. CONCLUSIONS: The incidence of bleb-associated endophthalmitis after guarded filtering surgery performed with adjunctive mitomycin is higher than the reported rate in eyes undergoing filtering surgery without the use of antifibrotic agents (0.2%-1.5%). Inferior limbal trabeculectomy carries the highest risk of infection. Eyes with mitomycin blebs maintained excellent filtration capacity. However, after treatment of the infection, the visual outcomes were generally poor.