RESUMEN
1. The effects of housing system and stocking density on growth performance and carcase yield of a commercial strain of broiler chickens reared under tropical environmental conditions may differ from temperate conditions.2. In two experimental periods, carried out during two contrasting seasons of the year (winter and summer), 240 Cobb 500 male chickens were randomly assigned in groups of 60 to 1 of 4 treatments, with 6 replicates in each, low stocking density with outdoor access (LO, 5 birds/m2); high stocking density with outdoor access (HO, 10 birds/m2); low stocking density indoors (LI, 5 birds/m2); high stocking density indoors (HI, 10 birds/m2). From 21 to 42 d old, body weight (BW) and feed intake (FI) were weekly recorded. Mortality was measured daily and carcase weight at slaughter. Indoor and outdoor temperature and relative humidity were measured daily.3. There was a tendency for chickens raised in the outdoor access to be heavier than those raised in the indoor treatments. Chickens raised in the low-density treatments in the first experimental period were significantly heavier, gained more weight and had lower value for feed conversion ratio (FCR) than those reared at high density. In the second experimental period mortality significantly increased on week 4 due to heat stress. Birds raised with outdoor access had an increased carcase yield compared to those raised exclusively indoors.4. In conclusion, low stocking density in combination with low environmental temperatures had enhancing effects on BW, BWG, FI and FCR, and the effects of housing system depended on stocking density. Low stocking density and outdoor access had positive effects on carcase yield.
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Crianza de Animales Domésticos , Pollos , Animales , Vivienda para Animales , Masculino , Estaciones del Año , Clima TropicalRESUMEN
Preclinical changes that precede the onset of symptoms and eventual diagnosis of Alzheimer's disease (AD) are a target for potential preventive interventions. A large body of evidence suggests that inflammation is closely associated with AD pathogenesis and may be a promising target pathway for such interventions. However, little is known about the association between systemic inflammation and preclinical AD pathophysiology. We first examined whether the acute-phase protein, alpha-2 macroglobulin (A2M), a major component of the innate immune system, was associated with cerebrospinal fluid (CSF) markers of neuronal injury in preclinical AD and risk of incident AD in the predictors of cognitive decline among normal individuals (BIOCARD) cohort. We find that A2M concentration in blood is significantly associated with CSF concentrations of the neuronal injury markers, tau and phosphorylated tau, and that higher baseline serum A2M concentration is associated with an almost threefold greater risk of progression to clinical symptoms of AD in men. These findings were replicated in the Alzheimer's Disease Neuroimaging (ADNI) study. Then, utilizing a systems level approach combining large multi-tissue gene expression datasets with mass spectrometry-based proteomic analyses of brain tissue, we identified an A2M gene network that includes regulator of calcineurin (RCAN1), an inhibitor of calcineurin, a well-characterized tau phosphatase. A2M gene and protein expression in the brain were significantly associated with gene and protein expression levels of calcineurin. Collectively these novel findings suggest that A2M is associated with preclinical AD, reflects early neuronal injury in the disease course and may be responsive to tau phosphorylation in the brain through the RCAN1-calcineurin pathway.
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Enfermedad de Alzheimer/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Musculares/metabolismo , alfa-Macroglobulinas/metabolismo , Anciano , Enfermedad de Alzheimer/fisiopatología , Péptidos beta-Amiloides/metabolismo , Apolipoproteína E4/genética , Biomarcadores/líquido cefalorraquídeo , Encéfalo/metabolismo , Calcineurina , Cognición/fisiología , Trastornos del Conocimiento/metabolismo , Estudios de Cohortes , Proteínas de Unión al ADN , Progresión de la Enfermedad , Femenino , Regulación de la Expresión Génica/inmunología , Humanos , Inmunidad Innata , Inflamación/líquido cefalorraquídeo , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Neuroimagen , Neuronas , Fosforilación , Proteómica , alfa-Macroglobulinas/análisis , Proteínas tau/metabolismoRESUMEN
Lichenomphalia is a lichenized agaric genus characterized by its omphalinoid basidiomes. Lichenomphalia species are associated with unicellular green algae in the genus Coccomyxa and are mainly distributed in polar and alpine habitats. The aim of this work is to describe L. altoandina, a new species from northern Chile that grows among cushion plants over 3000 m above sea level in the Andes Mountains. The species is remarkable for living in highly saline environments, in some cases virtually on salt crusts. Lichenomphalia altoandina differs from other known species and particularly from L. aurantiaca, the most morphologically similar species, in its smooth and broader stipe and its slightly larger spores. Lichenomphalia altoandina is also morphologicaly and ecologically more similar to the core Lichenomphalia clade. Our phylogenetic study based on nuclear rDNA ITS and partial 28S sequences shows that L. altoandina belongs to the Protolichenomphalia clade and is sister to an unknown lineage, L. aff. umbellifera, from New Zealand.
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Agaricales/clasificación , Agaricales/aislamiento & purificación , Agaricales/genética , Agaricales/crecimiento & desarrollo , Chile , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Microscopía , Filogenia , ARN Ribosómico 28S/genética , Salinidad , Análisis de Secuencia de ADN , Suelo/química , Microbiología del Suelo , Esporas Fúngicas/citologíaRESUMEN
OBJECTIVE: Unicompartmental knee arthroplasty (UKA) revision is usually due to the degenerative degree of knee articular osteochondral tissue in the untreated compartment. However, it is difficult to simulate the biomechanical behavior on this tissue accurately. This study presents and validates a reliable system to predict which osteoarthritis (OA) patients may suffer revision as a result of biomechanical reasons after having UKA. DESIGN: We collected all revision cases available (n = 11) and randomly selected 67 UKA cases to keep the revision prevalence of almost 14%. All these 78 cases have been followed at least 2 years. An elastic model is designed to characterize the biomechanical behavior of the articular osteochondral tissue for each patient. After calculated the force on the tissue, finite element method (FEM) is applied to calculating the strain of each tissue node. Kernel Ridge Regression (KRR) method is used to model the relationship between the strain information and the risk of revision. Therefore, the risk of UKA revision can be predicted by this integrated model. RESULTS: Leave-one-out (LOO) cross-validation (CV) is implemented to assess the prediction accuracy. As a result, the mean prediction accuracy is 93.58% for all these cases, demonstrating the high value of this model as a decision-making assistant for surgical plaining of knee OA. CONCLUSIONS: The results of this study demonstrated that this integrated model can predict the risk of UKA revision with theoretically high accuracy. It combines bio-mechanical and statistical learning approach to create a surgical planning tool which may support clinical decision in the future.
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Artroplastia de Reemplazo de Rodilla , Humanos , Articulación de la Rodilla , Prótesis de la Rodilla , Osteoartritis de la Rodilla , Reoperación , Riesgo , Resultado del TratamientoRESUMEN
Recently we have proposed the use of Tikhonov regularization with temporal smoothness constraints to estimate the BOLD fMRI hemodynamic response function (HRF). The temporal smoothness constraint was imposed on the estimates by using second derivative information while the regularization parameter was selected based on the generalized cross-validation function (GCV). Using one-dimensional simulations, we previously found this method to produce reliable estimates of the HRF time course, especially its time to peak (TTP), being at the same time fast and robust to over-sampling in the HRF estimation. Here, we extend the method to include simultaneous temporal and spatial smoothness constraints. This method does not need Gaussian smoothing as a pre-processing step as usually done in fMRI data analysis. We carried out two-dimensional simulations to compare the two methods: Tikhonov regularization with temporal (Tik-GCV-T) and spatio-temporal (Tik-GCV-ST) smoothness constraints on the estimated HRF. We focus our attention on quantifying the influence of the Gaussian data smoothing and the presence of edges on the performance of these techniques. Our results suggest that the spatial smoothing introduced by regularization is less severe than that produced by Gaussian smoothing. This allows more accurate estimates of the response amplitudes while producing similar estimates of the TTP. We illustrate these ideas using real data.
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Encéfalo/fisiología , Hemodinámica , Imagen por Resonancia Magnética , Modelos Biológicos , Oxígeno/sangre , Algoritmos , Simulación por Computador , HumanosRESUMEN
BACKGROUND: Cardiac hemangiomas are rare cardiac neoplasia usually diagnosed in autopsies, from being asymptomatic to debuting with sudden death. The largest hemangioma published in the literature is of 130 mm size, we present the following case of a successful cardiac hemangioma excision of 280 × 35 mm in size, diagnosed due to recurrent cardiac symptoms. CASE PRESENTATION: A 48-year-old female patient, Jehovah's Witness, with no previous diagnoses, is admitted due to recurrent syncopal episodes in the previous months. A transthoracic echocardiogram diagnosed a tumor in the right atrium and inferior vena cava producing a diastolic right ventricular, with preservation of the left ventricular ejection fraction at 55%. Given the high mortality risk, a surgical intervention was performed immediately. Successful excision was completed confirming a 280 × 35 mm mass without any complications, consistent with hemangioma on histopathology. Postoperative recovery showed no recurrence or complications. CONCLUSIONS: Cardiac hemangiomas are rare and its clinical course can be varied from patient to patient. We present excision of a large cardiac mass with a high mortality risk due to its size and the patient's spiritual beliefs.
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Atrios Cardíacos , Neoplasias Cardíacas/diagnóstico , Hemangioma/diagnóstico , Vena Cava Inferior , Diagnóstico Diferencial , Ecocardiografía , Femenino , Neoplasias Cardíacas/complicaciones , Neoplasias Cardíacas/diagnóstico por imagen , Neoplasias Cardíacas/cirugía , Hemangioma/complicaciones , Hemangioma/diagnóstico por imagen , Hemangioma/cirugía , Humanos , Testigos de Jehová , Persona de Mediana Edad , Síncope/etiologíaRESUMEN
CONCLUSIONS: The hydrodynamic model of the labyrinth spaces (LHM) is a useful tool for research on implantable audioprostheses, in particular to develop suitable actuators using MEMS technology (micro-electromechanic machine system). It has other potential applications for auditory research. OBJECTIVES: The energy reaching the labyrinth fluids is crucial information for developing prostheses to substitute the tympanic-ossicular system because adequate stimulation of the cochlear partition is essential. However, in vivo measurements in human ears are not currently available. Therefore a model of the normal labyrinth resembling its hydrodynamic properties becomes a valuable tool. It could allow comparison of different processing systems, algorithms and transducers, to develop new audioprostheses and improve their effectiveness and efficiency. MATERIALS AND METHODS: This work presents one LHM that emulates the conduction of the stimuli from the stapes footplate through the labyrinthine fluids, including its dimensions and physical properties, and some examples of measurements of perilymph stimulation by different audioprostheses and algorithms. RESULTS. As shown in the reported examples, this LHM provided effective measurement of acoustic stimulation across the whole human auditory frequency and intensity spectrum. Air-delivered and direct stimulation methods are possible. This provided convenient information for the actuator development and allowed comparison between different prototypes, stimulation patterns and algorithms.
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Implantes Cocleares , Oído Interno/anatomía & histología , Oído Interno/fisiología , Modelos Anatómicos , Perilinfa/fisiología , Algoritmos , Diseño de Equipo , HumanosRESUMEN
To evaluate the relation of the dose of intravenous dipyridamole on results of thallium and echocardiographic testing, the results of standard- (0.56 mg/kg/4 minutes) versus high- (0.84 mg/kg/10 minutes) dose dipyridamole were obtained 9 +/- 3 days after uncomplicated acute myocardial infarction in 57 patients. New wall motion abnormalities were compared with redistribution of thallium imaging and results of discharge coronary angiography. The sensitivity of thallium in predicting the presence of multivessel coronary artery disease was significantly (p < 0.01) higher (85%) than echocardiography (53%) and was unaffected by the dose. However the sensitivity of echocardiography was better with the higher dose (53 vs 14%). Minor adverse effects occurred in 34 patients (59%) after receiving the high dose and only in 4 patients (7%) after the standard dose (p < 0.001). Thus, thallium-201 scintigraphy during standard-dose dipyridamole infusion is more effective than high-dose dipyridamole echocardiographic testing in safely identifying patients who could benefit from early invasive evaluation and therapy.
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Dipiridamol/administración & dosificación , Ecocardiografía , Infarto del Miocardio/diagnóstico por imagen , Ventriculografía con Radionúclidos , Radioisótopos de Talio , Angina de Pecho/inducido químicamente , Presión Sanguínea/efectos de los fármacos , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Vasos Coronarios/diagnóstico por imagen , Dipiridamol/efectos adversos , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Contracción Miocárdica/efectos de los fármacos , Contracción Miocárdica/fisiología , Infarto del Miocardio/fisiopatología , Función Ventricular/efectos de los fármacos , Función Ventricular/fisiologíaRESUMEN
The outer table of calvarium is a useful donor site for facial reconstruction after resection of tumors. Large defects, especially when associated with multiple operations and radiotherapy, are poor recipient beds for nonvascularized bone grafts. A technique for the transfer of vascularized outer table has been developed and used in 11 patients for reconstruction of tumor defects. Satisfactory correction of both functional and esthetic problems has been achieved with satisfactory long-term stability and low morbidity.
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Huesos Faciales/cirugía , Neoplasias Craneales/cirugía , Colgajos Quirúrgicos , Adolescente , Adulto , Niño , Humanos , Masculino , Persona de Mediana Edad , Cráneo/irrigación sanguíneaRESUMEN
Perforation of the gallbladder is a serious complication of acute and subacute cholecystitis which is rarely recognized before operation, either by clinical or radiological methods. Five cases of walled-off perforation of the gallbladder have been diagnosed by computed tomographic (CT) studies, within a period of less than one year. The studies were routinely made in the supine projection, with or without an intravenous injection of contrast medium. Scanning time was 4.7 seconds. The patients did not receive any pre-medication. CT demonstrated direct signs of the perforations: calculi outside the gallbladder; the ruptured segment of the wall. Indirect signs were also readily detected: localized abscesses, occasionally multiple or situated distant from the gallbladder; gallstones; thickening of the wall of the gallbladder. CT may have an important role in preoperative diagnosis of complicated acute cholecystitis and in the surgical management of patients with this condition, if ultrasound examination fails to establish the diagnosis or cannot be done for technical reasons.
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Enfermedades de la Vesícula Biliar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Anciano , Colecistitis/complicaciones , Femenino , Enfermedades de la Vesícula Biliar/etiología , Humanos , Masculino , Persona de Mediana Edad , Rotura EspontáneaRESUMEN
Eight patients with unilateral and four with bilateral (4) unpalpable testes were evaluated with CT for localization. All patients were later submitted to laparascopy and/or surgery and 13 cryptorchid testes and 3 atrophic or agenesic testes were found. CT detected correctly 11 of the cryptorchid testes - (85%) with one false positive and one false negative finding. In the three atrophic or agenesic testes, CT did not identify any image suspicious of being a testis, so there three were no false positive studies here. It is concluded that CT is an accurate noninvasive method for the preoperative detection of cryptorchid testes.
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Criptorquidismo/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adolescente , Adulto , Niño , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Restenosis remains the main limitation of percutaneous transluminal coronary angioplasty (PTCA). Since it seems likely that restenosis not severe enough to induce ischemia may be better detected with pharmacological testing than with exercise, we investigated whether dipyridamole thallium scintigraphy is better than exercise-electrocardiogram and exercise-thallium in predicting restenosis after PTCA. Noninvasive tests and re-angiography were performed in 61 consecutive patients, 5-6 months after successful single vessel PTCA. Detection of vessel stenosis greater than or equal to 50% was used as angiographic criteria for restenosis. Exercise-induced angina, ST segment depression greater than or equal to 1 mm at exercise-electrocardiogram and reversible perfusion defects in the area supplied by the dilated vessel, during either dipyridamole and exercise-thallium, were considered noninvasive abnormal responses. The overall restenosis rate was 41% (25/61). Angina was the most specific (97%) of all criteria for restenosis, but also one of the least sensitive (40%), slightly better than exercise-ECG (24%). Exercise-thallium had lower sensitivity (72% vs 88%, p less than 0.05) and negative predictive value (82% vs 91%, p less than 0.05) than dipyridamole-thallium. In patients positive at both exercise-thallium and dipyridamole-thallium testing, mean stenosis at follow-up was more severe (73 +/- 23%) than in patients with positive dipyridamole-thallium and negative exercise-thallium (55 +/- 26%) results, but the difference did not reach statistically significant levels. For these reasons, dipyridamole-thallium seems to be an acceptable alternative to exercise thallium to follow patients after initially successful PTCA.
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Enfermedad Coronaria/diagnóstico , Prueba de Esfuerzo/métodos , Anciano , Angioplastia Coronaria con Balón , Angiografía Coronaria , Enfermedad Coronaria/terapia , Dipiridamol , Electrocardiografía , Prueba de Esfuerzo/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Recurrencia , Radioisótopos de Talio , Resultado del TratamientoRESUMEN
A protocol utilizing high preoperative doses of altrenogest (Regu-Mate) and a "balanced" general anesthesia regimen consisting of isoflurane at subanesthetic doses supplemented with intravenous doses of sodium thiopental was developed to prevent preterm labor, minimize intracranial fetal cerebral edema, and decrease postpartum mortality of fetal swine after undergoing complex in utero craniofacial procedures. A total of 20 fetal piglets at 75% gestation were exposed to prolonged (> 3 h) anesthesia conditions of which 7 piglets were randomly selected to undergo experimental craniofacial procedures consisting of periosteal stripping of frontal and parietal bone segments with/without extensive coronal suture fusion procedures. Neither sows nor piglets were lost to anesthetic complications during the initial laparotomy or subsequent cesarean delivery. None of the sows experienced uterine sepsis or underwent preterm labor. The overall survival rate for all piglets exposed to prolonged anesthesia conditions was 95% at 4 weeks and 45% at 11 weeks after surgery. The experimental group's survival was 85.7% at 4 weeks and 28.5% at 11 weeks after surgery.
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Anestesia General/métodos , Anomalías Craneofaciales/cirugía , Feto/cirugía , Anestésicos por Inhalación/farmacología , Animales , Anomalías Craneofaciales/mortalidad , Modelos Animales de Enfermedad , Femenino , Isoflurano/farmacología , Cuidados Posoperatorios , Embarazo , Congéneres de la Progesterona/farmacología , Porcinos , Factores de Tiempo , Acetato de Trembolona/análogos & derivados , Acetato de Trembolona/farmacologíaRESUMEN
The vascularization of the scalp and calvarium was studied in cadavers to better define the design of vascularized split- or full-thickness calvarial bone flaps. Selective dye injections of the superficial temporal and internal maxillary arteries established a horizontal and vertical network of vessels within and between each layer of the scalp. The periosteum of the frontoparietal region continues over the temporal aponeurosis as a separate, distinct layer, the innominate fascia, which is irrigated by numerous proximal branches of the superficial and deep temporal arteries. The periosteum can sustain the outer table of the calvarium by means of multiple small, vertical perforators. Between the periosteum and the outer table is a thin areolar layer of subperiosteum which continues beneath the temporal muscle. We feel that vascularized outer-table calvarial flaps can safely be pedicled using only the temporal aponeurosis, innominate fascia, and periosteum without including the galea or temporal muscle.
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Cuero Cabelludo/trasplante , Cráneo/trasplante , Colgajos Quirúrgicos , Vasos Sanguíneos/anatomía & histología , Cara/cirugía , Humanos , Cuero Cabelludo/irrigación sanguínea , Cráneo/irrigación sanguíneaRESUMEN
Based on an anatomic study of the vascularization of the calvarium in cadavers, a technique for the transfer of vascularized outer-table calvarial bone has been developed. The outer table of the calvarium receives numerous small perforators from its overlying periosteum. The periosteum is continuous with a distinct fascial layer overlying the temporal aponeurosis which we have termed the innominate fascia. Because of a network of anastomosing vessels from proximal branches of the superficial temporal artery and perforating branches of the deep temporal artery, the outer table of the calvarium can be carried on a pedicle which contains the temporal aponeurosis, innominate fascia, and periosteum. Thirty-seven vascularized outer-table calvarial bone flaps have been performed for a variety of craniofacial reconstructive deformities. Remarkable stability and lack of resorption have led the authors to favor this method of reconstruction particularly in poorly vascularized or previously infected recipient beds.
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Cara/cirugía , Cráneo/trasplante , Colgajos Quirúrgicos , Adolescente , Adulto , Niño , Cara/anomalías , Traumatismos Faciales/cirugía , Femenino , Humanos , Masculino , Métodos , Persona de Mediana Edad , Cráneo/irrigación sanguínea , Cirugía Plástica/métodosRESUMEN
This study demonstrates that fibrin monomers can be polymerized into moldable gels and used for the encapsulation of isolated chondrocytes. This biologically derived scaffold will maintain three-dimensional spatial support, allowing new tissue development in a subcutaneous space. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were combined with cyroprecipitate and polymerized with bovine thrombin to create a fibrin glue gel with a final cell density of 12.5 x 10(6) cells/ml. The polymer-chondrocyte constructs were implanted subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analysis including deoxyribonucleic acid (DNA) and glycosaminoglycan quantitation confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from 12 implantation sites consisting of chondrocytes alone or fibrin glue substrates did not demonstrate any gross or histologic evidence of neocartilage formation. Moldable autogenous fibrin glue polymer systems have a potential to serve as alternatives to current proprietary polymer systems used for tissue engineering cartilage as well as autogenous grafts and alloplastic materials used for facial skeletal and soft-tissue augmentation.
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Cartílago Articular/crecimiento & desarrollo , Condrocitos/trasplante , Adhesivo de Tejido de Fibrina , Animales , Ingeniería Biomédica , Bovinos , Femenino , Humanos , Ratones , Ratones Desnudos , PolímerosRESUMEN
This study demonstrates that polyethylene oxide gels, which are biocompatible and biodegradable synthetic polymers, can be utilized for the encapsulation of isolated chondrocytes and maintenance of three-dimensional spatial support for new tissue development. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were added to a 20% polyethylene oxide solution in Ham's F-12 medium to generate a final cellular density of 10 x 10(6)/mL. The polymer-chondrocyte constructs were injected through a 22-gauge needle in 500-microliters aliquots subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analyses including deoxyribonucleic acid and glycosaminoglycan quantitative analyses confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from eight implantation sites consisting of chondrocytes alone or polyethylene oxide substrates did not demonstrate any gross or histologic evidence of neocartilage formation. These findings demonstrate the potential use of an injectable and moldable polymer substrate that can support cell proliferation and matrix synthesis after subcutaneous transplantation for neocartilage generation. The use of functional biologic tissue substitutes may serve as an alternative solution to current methods of augmentation or reconstruction of structural craniofacial contour deformities.
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Cartílago/citología , Polietilenglicoles , Prótesis e Implantes , Animales , Materiales Biocompatibles , Células Cultivadas , Matriz Extracelular/metabolismo , Estudios de Factibilidad , Femenino , Glicosaminoglicanos/análisis , Ratones , Ratones DesnudosRESUMEN
Tikhonov regularization has been widely used in electrical tomography to deal with the ill-posedness of the inverse problem. However, due to the fact that discontinuities are strongly penalized, this approach tends to produce blurred images. Recently, a lot of interest has been devoted to methods with edge-preserving properties, such as those related to total variation, wavelets and half-quadratic regularization. In the present work, the performance of an edge-preserving regularization method, called ARTUR, is evaluated in the context of magnetic induction tomography (MIT). ARTUR is a deterministic method based on half-quadratic regularization, where complementary a priori information may be introduced in the reconstruction algorithm by the use of a nonnegativity constraint. The method is first tested using an MIT analytical model that generates projection data given the position, the radius and the magnetic permeability of a single nonconductive cylindrical object. It is shown that even in the presence of strong Gaussian additive noise, it is still able to recover the main features of the object. Secondly, reconstructions based on real data for different configurations of conductive nonmagnetic cylindrical objects are presented and some of their parameters estimated.
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Magnetismo/instrumentación , Modelos Teóricos , Tomografía/métodos , Algoritmos , Artefactos , Simulación por Computador , Campos ElectromagnéticosRESUMEN
The vascular supply to the upper limb is reviewed and several specific myocutaneous and fasciocutaneous flaps are discussed. Also considered is specific coverage of defects in the shoulder, scapula, humerus, elbow, and radial or ulnar bones.
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Brazo/cirugía , Colgajos Quirúrgicos , Traumatismos del Brazo/cirugía , Axila/cirugía , Quemaduras/complicaciones , Contractura/cirugía , Antebrazo/cirugía , Mano/cirugía , Humanos , Métodos , Neoplasias/cirugía , Músculos Pectorales , Complicaciones Posoperatorias/cirugíaRESUMEN
Using and old procedure to investigate fecal fermentation (FF), modified to make it quantitative a relation was recently found between exaggerated FF and meteorism. FF levels probable reflect the intensity of colonic fermentation. Consequently, it seems desirable to control FF to be able, then, to control exaggerated colonic fermentation in patients with meteorism. In the present communication, a report is made on the effect on FF levels, obtained with fecal samples from 22 patients with meteorism, exerted by the addition of: 1) an antibiotic, paramomycin, with a definite inhibitory capacity on coliform bacteria; 2) a chemotherapeutic agent, metronidazolee, with a definitive inhibitory capacity on anerobic bacteria; and 3) a mixture of paramocycin and metronidazole. Basal FF was normal in 12 out of 22 fecal samples, and exaggerated in the remaining 10 samples. In about all the samples - as well in the samples that rendered normal basal FF as in the samples that rendered exaggerated basal FF - the addition of paramomycin, of metronidazole and of paramomycin and metronidazole in combination significantly reduced the FF levels; and the reductions exerted by each of the additions were not significantly different among each other. Analyzing the obtained results, it was concluded: a) that fecal anaerobic bacteria are, very probably, the main agents of FF, while coliform bacteria only favour the action of the former; and b) that paramomycin, metronidazole or paramomycin and metronidazol in combination could be useful to manage patients with meteorism and exaggerated FF.