RESUMEN
In unconventional superconductors, understanding the form of the pairing interaction is the primary goal. In this regard, Raman spectroscopy is a very useful tool, as it identifies the ground state and also the subleading pairing channels by probing collective modes. Here, we propose a general theory for a multiband Raman response and identify new features in the spectrum that can provide a robust test for a pairing theory. We identify multiple Bardasis-Schrieffer type collective modes and connect the weights of these modes to the subleading gap structures within a microscopic pairing theory. While our conclusions are completely general, we apply our approach to interpret the specific case of B_{1g} Raman scattering in hole-doped BaFe_{2}As_{2}.
RESUMEN
We show that electronic Raman scattering affords a window into the essential properties of the pairing potential V(k,k') of iron-based superconductors. In Ba0.6K0.4Fe2As2 we observe band dependent energy gaps along with excitonic Bardasis-Schrieffer modes characterizing, respectively, the dominant and subdominant pairing channel. The d(x(2)-y(2)) symmetry of all excitons allows us to identify the subdominant channel to originate from the interaction between the electron bands. Consequently, the dominant channel driving superconductivity results from the interaction between the electron and hole bands and has the full lattice symmetry. The results in Rb(0.8)Fe(1.6)Se(2) along with earlier ones in Ba(Fe(0.939)Co(0.061))(2)As(2) highlight the influence of the Fermi surface topology on the pairing interactions.
RESUMEN
We tested whether incoming sounds are processed differently depending on how the preceding sound sequence has been interpreted by the brain. Sequences of a regularly repeating three-tone pattern, the perceived organization of which spontaneously switched back and forth between two alternative interpretations, were delivered to listeners. Occasionally, a regular tone was exchanged for a slightly or moderately lower one (deviants). The electroencephalogram (EEG) was recorded while listeners continuously marked their perception of the sound sequence. We found that for both the regular and the deviant tones, the early exogenous P1 and N1 amplitudes varied together with the perceived sound organization. Percept-dependent effects on the late endogenous N2 and P3a amplitudes were only found for deviant tones. These results suggest that the perceived sound organization affects sound processing both by modulating what information is extracted from incoming sounds as well as by influencing how deviant sound events are evaluated for further processing.
Asunto(s)
Percepción Auditiva/fisiología , Corteza Cerebral/fisiología , Cognición/fisiología , Potenciales Evocados/fisiología , Estimulación Acústica , Adulto , Atención/fisiología , Electroencefalografía , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Factores de TiempoRESUMEN
BACKGROUND: The purpose of this study was to assess uncorrected far and near vision after implantation of a multifocal intraocular lens (IOL) in the second eye in patients with a unilateral monofocal IOL. PATIENTS AND METHODS: 13 cataract patients with a monofocal intraocular lens in one eye (SA60AT, Alcon) and postoperative emmetropia received a multifocal lens in the second eye (ReSTOR, Alcon). Two and six months postoperatively the clinical examination, far and near vision, near aniseikonia (AWAYA-New Aniseikonia Test), stereo vision (Lang I test) and the mesopic contrast sensitivity (F. A. C.T) were tested. In addition, the grade of satisfaction without glasses in general, and with far and near vision were noted on a visual analogue scale (0 - 10). Furthermore, independence from glasses and the presence of optical phenomena were assessed. RESULTS: The mean uncorrected far visual acuity 6 months postoperatively was 1.06 +/- 0.28 for the monofocal lens, 0.88 +/- 0.23 for the multifocal lens, and 1.16 +/- 0.24 binocularly. The uncorrected near visual acuity was Nieden 1 binocularly for all patients and ranged from Nieden 1 - 3 for the multifocal lens to Nieden 2 - 11 for the monofocal lens. 77% of the patients received the multifocal lens in their far dominant eye. The mean uncorrected near aniseikonia was < 1%. The mesopic contrast sensitivity showed no significant differences between the two IOL types and compared to binocular values. The satisfaction with the uncorrected visual acuity was in general 8.88 +/- 1.21, with the far visual acuity 9.42 +/- 1.24, and 7.33 +/- 1.72 with the near visual acuity. After 6 months 67% of the patients used glasses only for periods of prolonged reading. Halos and a low degree of glare were noted by 38.5% of patients 2 months postoperatively. At the 6 months visit 33.3% still had halos and only 8% glare. CONCLUSIONS: This first experience with the combined implantation of a monofocal and a multifocal lens revealed a marked improvement of the uncorrected near visual acuity compared to bilateral monofocal IOL implantation along with a high patient satisfaction.
Asunto(s)
Catarata/complicaciones , Catarata/rehabilitación , Implantación de Lentes Intraoculares/instrumentación , Implantación de Lentes Intraoculares/métodos , Lentes Intraoculares , Presbiopía/complicaciones , Presbiopía/rehabilitación , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
We investigated the clinical and radiological outcome of trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia in 38 consecutive patients (45 knees) with a mean follow-up of 8.3 years (4 to 14). None had recurrence of dislocation after trochleaplasty. Post-operatively, patellofemoral pain, present pre-operatively in only 35 knees, became worse in 15 (33.4%), remained unchanged in four (8.8%) and improved in 22 (49%). Four knees which had no pain pre-operatively (8.8%) continued to have no pain. A total of 33 knees were available for radiological assessment. Post-operatively, all but two knees (93.9%) had correction of trochlear dysplasia radiologically but degenerative changes of the patellofemoral joint developed in 30% (10) of the knees. We conclude that recurrent patellar dislocation associated with trochlear dysplasia can be treated successfully by trochleaplasty, but the impact on patellofemoral pain and the development of patellofemoral osteoarthritis is less predictable. Overall, subjective patient satisfaction with restored patellofemoral stability after trochleaplasty appeared to outweigh its possible sequelae.
Asunto(s)
Enfermedades del Desarrollo Óseo/cirugía , Luxación de la Rótula/cirugía , Adolescente , Adulto , Enfermedades del Desarrollo Óseo/complicaciones , Enfermedades del Desarrollo Óseo/diagnóstico por imagen , Femenino , Fémur/diagnóstico por imagen , Fémur/cirugía , Estudios de Seguimiento , Humanos , Inestabilidad de la Articulación/complicaciones , Inestabilidad de la Articulación/diagnóstico por imagen , Inestabilidad de la Articulación/cirugía , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/fisiopatología , Articulación de la Rodilla/cirugía , Masculino , Dimensión del Dolor , Rótula/diagnóstico por imagen , Rótula/cirugía , Luxación de la Rótula/complicaciones , Luxación de la Rótula/diagnóstico por imagen , Complicaciones Posoperatorias , Radiografía , Recurrencia , Resultado del TratamientoRESUMEN
BACKGROUND: In literature there are only few data which describe the influence of occupation on the development of rotator cuff disease. METHODS: In a retrospective study, 760 open rotator cuff repairs were analysed and related to the profession and occupational load. Exclusion criteria were traumatic tears and sports injuries. All male persons were statistically analysed and the data compared with occupational patterns of the region, obtained from the Federal Statistical State Office. RESULTS: Rotator cuff repairs were performed in 472 males who had no evidence for a traumatic origin. After statistical analysis (p < 0.001) we found significantly more patients working in agriculture and forestry (6.38% versus 1.07% in Bavaria) and in the building industry (35.11% versus 13.40% in Bavaria). CONCLUSIONS: Our data suggest that working exposure increases the risk or leads to the clinical manifestation of rotator cuff tears. Although a detailed analysis of individual physical exposure is not available yet, the statistical results indicate that rotator cuff tears must be taken into consideration as a result of ergonomic exposure.
Asunto(s)
Empleo/estadística & datos numéricos , Enfermedades Profesionales/epidemiología , Medición de Riesgo/métodos , Lesiones del Manguito de los Rotadores , Síndrome de Abducción Dolorosa del Hombro/epidemiología , Carga de Trabajo/estadística & datos numéricos , Adulto , Anciano , Comorbilidad , Femenino , Alemania/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Rotura/epidemiologíaRESUMEN
BACKGROUND: Unilateral lamellar keratotomy (LKT) and curved dual lamellar keratotomy (BLK) were compared to evaluate the influence of incisional correction of astigmatism on the optical quality of the cornea. PATIENTS AND METHODS: Forty-six patients with a preoperative astigmatism greater than 1.5 D were studied. LKT was performed on 30 eyes during cataract surgery and 20 eyes were treated with a BLK. Preoperatively and 4 weeks after surgery the corneal topographical data were analyzed with ray tracing in a 3-mm optical zone. The potential visual acuity (PVA) and the optical distortion (OD), which is represented by the width of the point spread in the optical center, were calculated as parameters for the optical quality. RESULTS: The mean surgically induced astigmatism was 2.6+/-1.5 D for the LKT group and 3.5+/-1.4 D for the BLK group. The PVA decreased significantly in the LKT group from 1.2+/-0.2 to 1.0+/-0.3 (p=0.008), whereas in the BLK group the PVA remained unchanged (p=0.916). The OD increased from 6.6+/-0.9 microm to 7.9+/-2.0 microm (p=0.007) in the LKT group. In the BLK group the values were stable (p=0.843). CONCLUSIONS: The optical quality of the cornea decreased after unilateral keratotomy in the early postoperative period. Thus, optical quality values should also be considered in incisional correction of astigmatism.
Asunto(s)
Astigmatismo/cirugía , Córnea/cirugía , Topografía de la Córnea , Complicaciones Posoperatorias/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Extracción de Catarata , Femenino , Humanos , Masculino , Cómputos Matemáticos , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Procesamiento de Señales Asistido por Computador , Agudeza VisualRESUMEN
For some air-communicating well-type chambers used for low-energy brachytherapy source assay, deviations from expected values of measured air kerma strength were observed at low pressures associated with high altitudes. This effect is consistent with an overcompensation by the air density correction to standard atmospheric temperature and pressure (P(TP)). This work demonstrates that the P(TP) correction does not fully compensate for the high altitude pressure effects that are seen with air-communicating chambers at low photon energies in the range of 20-100 keV. Deviations of up to 18% at a pressure corresponding to an approximate elevation of 8500 ft for photon energies of 20 keV are possible. For high-energy photons and for high-energy beta emitters in air-communicating chambers the P(TP) factor is applicable. As expected, the ambient pressure does not significantly affect the response of pressurized well chambers (within 1%) to either low- or high-energy photons. However, when used with beta emitters, pressurized chambers appear to exhibit a slight dependence on the ambient pressure. Using measured data, the response and correction factors were determined for three models of air-communicating well chambers for low-energy photon sources at various pressures corresponding to elevations above sea level. Monte Carlo calculations were also performed which were correlated with the experimental findings. A more complete study of the Monte Carlo calculations is presented in the accompanying paper, "The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR1000 Plus."
Asunto(s)
Artefactos , Braquiterapia/instrumentación , Radiometría/instrumentación , Presión Atmosférica , Benchmarking/métodos , Braquiterapia/métodos , Braquiterapia/normas , Calibración , Dosis de Radiación , Radiometría/métodos , Radiometría/normas , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
In a prospective clinical trial, first the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D) was tested for reliability, validity, and responsiveness in 23 patients with rotator cuff tears, and secondly the Short Form (SF)-36, and the Constant score were evaluated comparatively in 45 patients with rotator cuff tear undergoing open repair. Retest reliability was excellent for the functional index of the SMFA-D and satisfactory for the bother index. The SMFA-D showed good validity and responsiveness. All three instruments demonstrated significantly the positive effect of rotator cuff repair at 12-month follow-up. Using comparable scales, effect sizes were bigger with the SMFA-D than with the SF-36 and as big as the Constant score. Significant correlations of the SMFA-D indices with the SF-36 scales and the Constant score could be shown preoperatively. At 12-month follow-up, all correlations between SMFA-D indices, SF-36 scales, and Constant score function scales were still significant. We recommend use of the SMFA-D to assess changes in functional status concerning patients with rotator cuff tear undergoing open repair.
Asunto(s)
Indicadores de Salud , Lesiones del Manguito de los Rotadores , Manguito de los Rotadores/cirugía , Encuestas y Cuestionarios , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Ortopédicos , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND AND AIM: The diagnosis of submucosal fundal varices is challenging. Currently, endoscopy and endoscopic ultrasound (EUS) are considered most useful for this purpose. The aim of this study was to evaluate if multi-detector row CT (MDCT) angiography contributes to the diagnosis of submucosal fundal varices. PATIENTS AND METHODS: Twenty two patients with endoscopically suspected fundal varices were prospectively included in the study. All patients underwent EUS and MDCT angiography. Levels of agreement between EUS and MDCT angiography for the detection of submucosal and perigastric fundal varices were evaluated by three blinded independent readers. In addition, variceal size and location, as well as afferent and efferent vessels of the submucosal varices, were determined. RESULTS: Good or excellent image quality of MDCT angiography was obtained in 21/22 patients (95%). Based on EUS, submucosal varices were detected in 16 of 22 patients (73%) and perigastric varices in 22/22 patients (100%). Using MDCT angiography, the presence of submucosal varices was confirmed in all of these 16 patients by all three readers. Perigastric varices were also confirmed in all 22 patients by all three readers. In addition, all three readers noted the presence of a submucosal varix in an additional patient which was not detected on initial EUS. MDCT angiography showed an excellent interobserver reliability with regard to variceal diameter (kappa=0.90) and variceal location (kappa=0.94). Based on MDCT angiography, afferent and efferent vessels of submucosal varices included the left gastric vein in 11 (65%), the posterior/short gastric veins in 15 (88%), gastrorenal shunts in 10 (59%), the left inferior phrenic vein in six (35%), and the left pericardiophrenic vein in six (35%) of 17 patients. CONCLUSIONS: MDCT angiography is equivalent to EUS in terms of detection and characterisation of fundal varices, in particular with regard to the distinction between submucosal and perigastric fundal varices.
Asunto(s)
Várices Esofágicas y Gástricas/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Angiografía/métodos , Endosonografía , Várices Esofágicas y Gástricas/patología , Estudios de Factibilidad , Femenino , Fundus Gástrico/irrigación sanguínea , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Estudios ProspectivosRESUMEN
A 22 year old man from Ethiopia suffered from progressive left inguinal pain and weight loss for ten months. The pain aggravated with leg movement, in particular with flexion of the left hip. ESR and CRP were slightly elevated, and a PPD was strongly positive. Abdominal ultrasound was normal but CT-scan revealed a left sided psoas abscess. Pott's disease was suspected and tuberculostatic therapy with INH, PZA, ETH, RIF was initiated immediately. A MRI of the spine excluded spondylodiscitis. Primary Tb psoas abscess was diagnosed. Treatment response after 5 weeks was clinically insufficient and CT-scan showed enlargement of the abscess. Treatment adherence was verified by drug prescriptions and INH urinary stix testing. M. tuberculosis, suspected microscopically in the puncture fluid, grew in culture and was fully drug sensitive. After 12 weeks, surgical abscess debridement had to be performed due to disease progression. The patient's health state improved considerably the first two postoperative months, inflammatory markers normalized, although a small residual abscess was still visible on CT. Subsequently, three months after surgery, pain reemerged, CT showed abscess progression. The patient had to be reoperated. Tb psoas abscess was a frequently described complication of Tb spondylodiscitis (Pott's disease) the first half of the last century and became rare thereafter in the Western hemisphere. However, the last two decades, due to migration policies and a worldwide increase of Tb epidemic because of socioeconomic destabilization and spread of the HIV-pandemic, Tb reemerged in Western countries. Therefore, physicians should be aware of atypical manifestations of tuberculosis. Primary Tb psoas abscess is extremely rare. Only four cases are described in the literature. In analogy to Pott's disease, therapy consists of tuberculostatic treatment, supported by surgical debridement.
Asunto(s)
Conducto Inguinal , Dolor/etiología , Absceso del Psoas/diagnóstico por imagen , Tuberculosis de la Columna Vertebral/diagnóstico por imagen , Tuberculosis/diagnóstico por imagen , Adulto , Diagnóstico Diferencial , Humanos , Procesamiento de Imagen Asistido por Computador , Conducto Inguinal/diagnóstico por imagen , Masculino , Dolor/diagnóstico por imagen , Recurrencia , Tomografía Computarizada por Rayos XRESUMEN
The aim of this study was to quantify the clinical value of using electrical impedance scanning (EIS) as an adjunct to other diagnostic techniques in order to identify cancerous tissue based upon its inherent altered local dielectric properties. 210 consecutive women with 240 sonographically and/or mammographically suspicious findings were examined using EIS. All lesions were histologically-proven. 86/103 malignant and 91/137 benign lesions were correctly identified using EIS (87.8% sensitivity, 66.4% specificity). NPV and PPV of 84.3% and 65.2% were observed, respectively. Excluding cases as defined by a priori criteria, i.e. lesions located deeper than 35 mm, lesions larger than 35 mm, and retroareolar lesions, a sensitivity of 85.5% was observed, and for invasive cancers, 91.7%. The detection rate for ductal carcinoma in situ (DCIS) was poor (57.1%, n=14). By adding EIS to mammography and ultrasound, the sensitivity rose from 86.4 to 95.1%, whereas the accuracy decreased from 82.3 to 75.7%. EIS appears to be of interest as an adjunct to breast diagnostic techniques, performing with a reasonable sensitivity. Further investigations on histomorphological characteristics and the reasons for false-negative findings are essential to gain further knowledge about the bioelectricity of breast lesions, and prove the value of this new technology.
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Neoplasias de la Mama/diagnóstico , Impedancia Eléctrica , Femenino , Humanos , Mamografía/normas , Persona de Mediana Edad , Sensibilidad y Especificidad , Ultrasonografía Mamaria/normasRESUMEN
Studies of intravascular brachytherapy to prevent restenosis following angioplasty have shown many promising results. Accurate dose rate tables based on detailed models of the brachytherapy sources are necessary for treatment planning. This work will present an away and along dose rate table for a 27 mm long catheter based 32P beta source. MD-55-2 radiochromic film has been exposed at five different depths (0.5 mm-4 mm) in a polystyrene phantom using a 27 mm long Guidant 32P beta source. The total dose to the active region of the film was determined using the absolute detector response of the MD-55-2 radiochromic film. The Monte Carlo code MCNP4B2 was also used to calculate the dose to the active region of the film using a detailed model of the source, encapsulation, and radiochromic film. The dose to film calculations showed good agreement with the measurements presented in this work with an average difference of 7%. The Monte Carlo calculations were also verified against previously published depth dose in water measurements determined using radiochromic film and plastic scintillator. The depth dose calculations in water showed good agreement with the previously published measurements with the calculations being about 2.5% lower than the film measurements and about 2.5% higher than the scintillator measurements. This work then uses the verified Monte Carlo code to present a dose rate table for the 32P intravascular beta source.
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Braquiterapia/métodos , Método de Montecarlo , Radioisótopos de Fósforo/uso terapéutico , Braquiterapia/estadística & datos numéricos , Reestenosis Coronaria/prevención & control , Electrones , Humanos , Modelos Estadísticos , Fantasmas de Imagen , Valores de Referencia , Película para Rayos XAsunto(s)
Linfoma no Hodgkin/etiología , Neoplasias Pleurales/etiología , Neumotórax Artificial/efectos adversos , Tuberculosis Pulmonar/complicaciones , Tuberculosis Pulmonar/cirugía , Anciano , Humanos , Linfoma no Hodgkin/tratamiento farmacológico , Linfoma no Hodgkin/patología , Masculino , Neoplasias Pleurales/tratamiento farmacológico , Neoplasias Pleurales/patología , Factores de RiesgoRESUMEN
ADP-ribosylation factor (ARF) GTPases and their regulatory proteins have been implicated in the control of diverse biological functions. Two main classes of positive regulatory elements for ARF have been discovered so far: the large Sec7/Gea and the small cytohesin/ARNO families, respectively. These proteins harbor guanine-nucleotide-exchange factor (GEF) activity exerted by the common Sec7 domain. The availability of a specific inhibitor, the fungal metabolite brefeldin A, has enabled documentation of the involvement of the large GEFs in vesicle transport. However, because of the lack of such tools, the biological roles of the small GEFs have remained controversial. Here, we have selected a series of RNA aptamers that specifically recognize the Sec7 domain of cytohesin 1. Some aptamers inhibit guanine-nucleotide exchange on ARF1, thereby preventing ARF activation in vitro. Among them, aptamer M69 exhibited unexpected specificity for the small GEFs, because it does not interact with or inhibit the GEF activity of the related Gea2-Sec7 domain, a member of the class of large GEFs. The inhibitory effect demonstrated in vitro clearly is observed as well in vivo, based on the finding that M69 produces similar results as a dominant-negative, GEF-deficient mutant of cytohesin 1: when expressed in the cytoplasm of T-cells, M69 reduces stimulated adhesion to intercellular adhesion molecule-1 and results in a dramatic reorganization of F-actin distribution. These highly specific cellular effects suggest that the ARF-GEF activity of cytohesin 1 plays an important role in cytoskeletal remodeling events of lymphoid cells.
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Factores de Intercambio de Guanina Nucleótido/antagonistas & inhibidores , Factores de Intercambio de Guanina Nucleótido/metabolismo , ARN/farmacología , Proteínas de Saccharomyces cerevisiae , Factor 1 de Ribosilacion-ADP/metabolismo , Actinas/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , Adhesión Celular/efectos de los fármacos , Moléculas de Adhesión Celular/antagonistas & inhibidores , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Tamaño de la Célula , Citoesqueleto/metabolismo , Proteínas Fúngicas/antagonistas & inhibidores , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Factores de Intercambio de Guanina Nucleótido/química , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Molécula 1 de Adhesión Intercelular/metabolismo , Células Jurkat , Datos de Secuencia Molecular , Mutación/genética , Conformación de Ácido Nucleico , Unión Proteica , Estructura Terciaria de Proteína , ARN/química , ARN/genética , ARN/metabolismo , Especificidad por Sustrato , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismo , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
GafChromic (MD-55-2) radiochromic film has become increasingly popular for medical applications and has proven to be useful for brachytherapy dosimetry. To measure the absolute dose near a brachytherapy source, the response of the proposed detector in the measurement conditions relative to the response of the detector in calibration conditions must be known. MD-55-2 radiochromic film has been exposed in four different photon beams, a 30 and 40 kVp tungsten anode x-ray beam, a 75 kVp orthovoltage therapy beam, and a 60Co teletherapy beam to measure the relative detector response. These measurements were combined with coupled photon/electron Monte Carlo transport calculations to determine the absolute detector response. The Los Alamos National Laboratory Monte Carlo transport code MCNP4B2 was used. The measured relative response of this batch of MD-55-2 film varies from 8.79 mOD/Gy, measured for the 60Co beam, by as much as 42% for the low-energy x-ray beams. However, the absolute detector response varies from 4.32 mOD/Gy for the 60Co beam by, at most, only 6.3%. In this work we demonstrate that the absolute detector response of MD-55-2 radiochromic film is a constant and independent of beam quality. Further, this work shows that MCNP4B2 accurately simulates the energy response and geometry artifacts of the radiochromic film.
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Braquiterapia/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Fenómenos Biofísicos , Biofisica , Braquiterapia/estadística & datos numéricos , Electrones/uso terapéutico , Humanos , Método de Montecarlo , Fotones/uso terapéutico , Radiometría/métodos , Radiometría/estadística & datos numéricos , Planificación de la Radioterapia Asistida por Computador/estadística & datos numéricos , Película para Rayos XRESUMEN
Beta3 integrin adhesion molecules play important roles in wound repair and the regulation of vascular development and three beta3 integrin isoforms (beta3-A, -B, -C) have been described so far. Surface expression of beta3 integrins is dynamically regulated through internalization of beta3 integrins, however, the molecular mechanisms are understood incompletely. To evaluate the role of the cytoplasmic domain of beta3 integrins for internalization, we have generated single chain chimeras with variant and mutated forms of beta3 cytoplasmic domains. Upon transient transfection into chinese hamster ovary cells, it was found that the beta3-A chimera had strongly reduced cell surface expression compared with the corresponding beta3-B, or beta3-C fusion proteins, or the tail-less constructs, whereas steady state levels of all chimeras were near identical. Studies employing cytoplasmic domain mutants showed that the NITY motif at beta3-A 756-759 is critical for plasma membrane expression of beta3-A. Furthermore, delivery of beta3-A to the cell surface was specifically modulated by the cytoplasmic protein beta3-endonexin, a previously described intracellular protein. Coexpression of the native, long form of beta3-endonexin, which does not interact with the beta3 tail, acted as a dominant negative inhibitor of beta3-A-internalization and enhanced steady-state surface expression of the beta3-A-chimera. Furthermore, anti-beta3 antibody-induced internalization of the native beta3 integrin (alpha(IIb)beta3 was dramatically reduced for the Tyr(759)-Ala substitution mutant (alpha(IIb)beta3) (Y759A) and expression of the long isoform of beta3-endonexin substantially decreased the internalization of wild-type alpha(IIb)beta3. Thus, the NITY motif of the beta-chain cytoplasmic domain is involved in stimulated internalization of the beta3 integrin A isoform and beta3-endonexin appears to couple the beta3-A isoform to a specific receptor-recycling pathway.
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Antígenos CD/metabolismo , Endocitosis/fisiología , Glicoproteínas de Membrana Plaquetaria/metabolismo , Secuencia de Aminoácidos , Animales , Antígenos CD/genética , Sitios de Unión , Células CHO , Membrana Celular/metabolismo , Cricetinae , Citoplasma/metabolismo , Regulación de la Expresión Génica , Proteínas Fluorescentes Verdes , Inmunoglobulinas/genética , Inmunoglobulinas/metabolismo , Integrina beta3 , Proteínas Luminiscentes/genética , Datos de Secuencia Molecular , Mutagénesis , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/genética , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Glicoproteínas de Membrana Plaquetaria/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismoRESUMEN
PURPOSE: To test the reproducibility of markings on mammography films set by a commercial computer aided detection (CAD) system. PATIENTS AND METHODS: One hundred unilateral mammography examinations (each in CC and MLO) of 100 patients with mammographically detected suspicious foci, which were histopathologically proven to be malignant, were scanned three times with the CAD system, retrospectively. Every fifth patient of the institutional tumor case sampler was enrolled in the study. Only cases with one visible lesion were included in the study. Reproducibility and sensitivity (in both the strict and the broader sense) were determined. Strict sensitivity means the correct set of markers in both images, whereas broader sensitivity means the correct set in at least one of the images. Sixteen of 100 malignancies were indicated by focal suspicious microcalcification clusters, 53 tumors by masses and 31 cases by both signs of breast cancer. The CAD evaluation was divided into only two different markers: one for microcalcifications and one for masses. Thus, 47 (16+31) tumor-induced microcalcifications and 84 (53+31) malignancy-related masses were checked using the CAD system. RESULTS: Eighteen of 100 unilateral mammography examinations revealed identical patterns in all three scans (18% reproducibility). Eleven of 47 suspicious focal microcalcification clusters and 43/84 masses were correctly marked on both mammographic views in all three CAD scans (strict and broader sensitivity, 23.4 and 51.1%, respectively). Six of 47 microcalcification clusters and 8/84 masses were totally missed in all images by the system (false negative rate, 12.8 and 9.6%, respectively). CONCLUSION: Reproducibility is essential for CAD systems. Currently, reproducibility of the used CAD system appears to be insufficient for clinical routine. Improvement of the system characteristics would make such systems valuable as a 'second reader' in clinical examination.
Asunto(s)
Mamografía/normas , Interpretación de Imagen Radiográfica Asistida por Computador/normas , Neoplasias de la Mama/diagnóstico por imagen , Reacciones Falso Negativas , Femenino , Humanos , Mamografía/instrumentación , Mamografía/métodos , Interpretación de Imagen Radiográfica Asistida por Computador/instrumentación , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Human B lymphocytes express an ATP-gated ion channel (P2Z receptor), which shares similarities with the recently identified P2X7 receptor. Using gene specific primers, we have now isolated P2X7 cDNA from the total RNA of human B lymphocytes. This hP2X7 receptor subtype was expressed in Xenopus oocytes and electrophysiologically characterized. The hP2X7 receptor is similar to, but does not completely match, P2Z of human B cells. The hP2X7 receptors resemble the P2Z receptors with regard to the ATP concentration of half maximal activation, reproducibility, permeation characteristics and lack of desensitization of the ATP-evoked currents. However, in contrast to the native lymphocytic P2Z receptor, the time course of activation of hP2X7 displayed an additional linearly increasing current component. Furthermore, a second, small and slowly deactivating current component exists only in hP2X7 expressed in oocytes. The activation and deactivation kinetics as well as permeation characteristics of hP2X7 are different from rat P2X7 recently expressed in oocytes. Unlike in mammalian cells, hP2X7 expressed in Xenopus oocytes is not sufficient to induce large non-selective pores.
Asunto(s)
Linfocitos B/metabolismo , Receptores Purinérgicos P2/metabolismo , Adenosina Trifosfato/farmacología , Animales , Secuencia de Bases , Cartilla de ADN/genética , Femenino , Humanos , Técnicas In Vitro , Activación del Canal Iónico , Canales Iónicos/efectos de los fármacos , Canales Iónicos/genética , Canales Iónicos/metabolismo , Cinética , Potenciales de la Membrana/efectos de los fármacos , Oocitos/metabolismo , Fenotipo , Ratas , Receptores Purinérgicos P2/efectos de los fármacos , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2X7 , Proteínas Recombinantes/efectos de los fármacos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidad de la Especie , Xenopus laevisRESUMEN
RATIONALE AND OBJECTIVES: The feasibility of radiofrequency (RF) ablation for the treatment of breast tumors was investigated in vitro. The best parameters for ablation of breast tissue were chosen. METHODS: Saline-enhanced RF ablation was performed in human breast tissue specimens and cow udder tissue. Temperature profiles were measured depending on RF power (20, 28, 36 W) and NaCl infusion rate (15, 30, 60 mL/h) using eight thermocouples. Lesion development was monitored by ultrasound. Thermolysis efficiency was measured by tissue weight determinations before and after ablation. RESULTS: After RF ablation of tissue samples, 73.6% turned into a fat/saline emulsion. Ultrasound monitoring showed a cone-shaped hyperechoic area during the first 2 minutes of RF ablation, followed by an irregular expansion of the area. Time-dependent spatial temperature curves were more homogeneous at low infusion rates (15 mL/h). Peak temperatures up to 160 degrees C were measured. CONCLUSIONS: Controlled RF ablation of breast tissue is feasible. The irregular expansion of RF lesions in fatty breast tissue is due to liquefied fat. Low saline interstitial infusion rates result in better control of lesioning.