Juxtaglomerular cell tumor as a rare cause of hypertension in adults

The juxtaglomerular cell tumor is a cause of secondary hypertension in adults. A 35-year-old female patient suffering from hypertension and low serum potassium had a 3 × 3 cm solid mass at the lower pole of left kidney diagnosed by abdominal sonography. Partial nephrectomy was performed and the postoperatory was uneventful. Normalization of blood pressure was observed within the first month.

Abordagem diagnóstica dos pacientes com suspeita de trombose venosa profunda dos membros inferiores

Deep venous thrombosis is a relatively common disease, which can present pulmonary embolism as a complication in its acute phase, and later the post-thrombotic syndrome. Thus, diagnosis should be made as soon as possible, in order to prevent or minimize such complications. Several studies have shown that the symptoms and the clinical signs are inaccurate for the deep venous thrombosis diagnosis and that complementary exams are necessary. As an attempt to simplify the patients' assessment, Well et al., in 1997, developed a clinical prediction index that combines symptoms, signs and risk factors for deep venous thrombosis and managed to make a simpler approach through an association of this index with the complementary exams. Phlebography has been considered the gold standard of complementary exams. However, since it is an invasive exam and thus subject to complications, other diagnostic methods were introduced aiming at making the diagnostic approach simpler and less invasive. Doppler ultrasound, duplex scan, impedance plethysmography, computed tomography, and blood tests such as the D-dimer are some of the available methods for assessing the patient with suspicion of deep venous thrombosis. Among them, duplex scan has shown excellent accuracy and it is currently widely accepted as the first choice test for approaching the patient with deep venous thrombosis. Several authors have suggested an association of diagnostic methods to simplify and make the assessment of such patients more cost-effective, leading to the introduction of a wide range of diagnostic strategies. The different diagnostic methods used for assessing deep venous thrombosis are discussed, as well as a review of the literature on the accuracy, advantages and disadvantages of these methods. Copyright © 2005 by Sociedade Brasileira de Angiologia e Cirurgia Vascular.

Síndrome de Eisenmenger na gravidez

Eisenmenger's syndrome consists of pulmonary hypertension with a reversed or bidirectional shunt at the atrioventricular, or aortopulmonary level. Eisenmerger's syndrome in pregnancy is usually associated with high mortality rates (nearly 30-50%). Unfortunately, pulmonary hypertension is aggravated during pregnancy and often leads to an unfavorable outcome. Here, we report a successful pregnancy in a woman with Eisenmenger syndrome.

Evaluación características operativas: ecografía 2D y Doppler color para diagnóstico de acretismo placentario, clínica universitaria colombia, bogotá.

La placenta ácreta es la implantación anómala de la placenta en la pared uterina. Se presenta en 0.9% de todos los embarazos; actualmente es una de las causas más importantes de morbimortalidad materna. Ecografía 2D y Doppler placentario son métodos diagnósticos de primera y segunda línea. Objetivo: Evaluar la utilidad diagnóstica de ecográfica 2D y Doppler color Placentario para diagnóstico de acretismo placentario en gestantes con factores de riesgo comparándolos con diagnóstico clínico e histopatológico; y determinar incidencia de acretismo placentario en población asistente a Clínica Universitaria Colombia. Metodología: Estudio de evaluación de tecnología diagnóstica. Entre Agosto a Noviembre de 2010 se incluyeron 53 gestantes entre 24 y 40 semanas de gestación con factores de riesgo para acretismo placentario. El desempeño diagnóstico de las pruebas se determinará por sensibilidad, especificidad, valores predictivos positivo y negativo. Las características demográficas de las pacientes y resultados neonatales se analizaron mediante proporción, media y rango. Resultados: Se determinó incidencia de acretismo placentario en 4,54% de las gestantes con presencia de factores de riesgo para esta patología. Los datos hasta el momento no nos permiten calcular valores de desempeño diagnóstico. Un caso termino en histerectomía por acretismo placentario. Conclusión: Con los datos preliminares registramos una incidencia de acretismo placentario de 1 en 22 pacientes. Revisión de literatura sustenta la necesidad de realización diagnostica prenatal que impacte en la morbimortalidad materna y fetal, haciendo necesario la evaluación diagnostica valida de herramientas como el Eco 2D y Doppler color en población a riesgo.

Evaluación características operativas : ecografía 2d y doppler color para diagnóstico de acretismo placentario, clínica universitaria Colombia, Bogotá

La placenta ácreta es la implantación anómala de la placenta en la pared uterina. Se presenta en 0.9% de todos los embarazos; actualmente es una de las causas más importantes de morbimortalidad materna. Ecografía 2D y Doppler placentario son métodos diagnósticos de primera y segunda línea. Objetivo: Evaluar la utilidad diagnóstica de ecográfica 2D y Doppler color Placentario para diagnóstico de acretismo placentario en gestantes con factores de riesgo comparándolos con diagnóstico clínico e histopatológico; y determinar incidencia de acretismo placentario en población asistente a Clínica Universitaria Colombia. Metodología: Estudio de evaluación de tecnología diagnóstica. Entre Agosto a octubre 2011 se incluyeron 137 gestantes entre 24 y 40 semanas de gestación con factores de riesgo para acretismo placentario. El desempeño diagnóstico de las pruebas se determinará por sensibilidad, especificidad, valores predictivos positivo y negativo. Las características demográficas de las pacientes y resultados neonatales se analizaron mediante proporción, media y rango. Resultados: En un grupo de 137 pacientes con factores de riesgo de acretismo placentario analizadas se obtuvo el dato de 119 en cuanto a la finalización del embarazo. Se observaron 4 casos con diagnóstico clínico e histopatológico de acretismo placentario, evidenciando una prevalencia del 2,9%. La ecografía 2D y Doppler en la detección de acretismo placentario con un nivel de confianza del 95%, presentaron sensibilidad del 100% (IC95% 87,5-100) y especificidad de 100% (IC95% 99,6-100). Conclusión: Con los datos analizados registramos una incidencia de acretismo placentario de 4 en 132 pacientes. Revisión de literatura sustenta la necesidad de realización diagnostica prenatal que impacte en la morbimortalidad materna y fetal, haciendo necesario la evaluación diagnostica valida de herramientas como el Eco 2D y Doppler color en población a riesgo.

Foetal echoencephalography and Doppler ultrasonography of the middle cerebral artery in canine foetuses

Objectives: This study aimed to evaluate the characteristics of the brain and vascular indicesof the middle cerebral artery of canine foetuses. Methods: Twenty-five bitches were selected. Tissue development, echogenicity, echotexture and brain echobiometric data were studied, and the major structures were identified between the 5th and 8th gestational weeks. The area and volume of the brain mass (BMA and BMV), cranial area and volume (AC and VC), brain mass index (BMI) and brain volume index (BVI) were determined. A single ultrasound examination was performed during each studied week (6th, 7th and 8th). Doppler ultrasonography was performed to assess the maximum and minimum velocity, resistance and pulsatility index of middle cerebral artery of the foetuses. Results: Echoencephalography was performed to evaluate the morphological characteristics of the central nervous system. Cerebral echobiometry indicated an increase in area and volume of the hemispheres and cranium (P<0·001) but no changes in BMI or BVI over the gestational period studied. Doppler ultrasonography identified increases in peak systolic velocity (P=0·0188) and end diastolic velocity (P=0·0274) and decreases in resistance index (P=0·0002) and pulsatility index (P<0·001). Clinical Significance: Echoencephalography and spectral Doppler ultrasonography of the middle cerebral artery in canine foetuses might be a useful technique for prenatal care. © 2013 British Small Animal Veterinary Association.

Laser doppler imaging in a paediatric burns population

Objective Laser Doppler imaging (LDI) was compared to wound outcomes in children's burns, to determine if the technology could be used to predict these outcomes. Methods Forty-eight patients with a total of 85 burns were included in the study. Patient median age was 4 years 10 months and scans were taken 0–186 h post-burn using the fast, low-resolution setting on the Moor LDI2 laser Doppler imager. Wounds were managed by standard practice, without taking into account the scan results. Time until complete re-epithelialisation and whether or not grafting and scar management were required were recorded for each wound. If wounds were treated with Silvazine™ or Acticoat™ prior to the scan, this was also recorded. Results The predominant colour of the scan was found to be significantly related to the re-epithelialisation, grafting and scar management outcomes and could be used to predict those outcomes. The prior use of Acticoat™ did not affect the scan relationship to outcomes, however, the use of Silvazine™ did complicate the relationship for light blue and green scanned partial thickness wounds. Scans taken within the 24-h window after-burn also appeared to be accurate predictors of wound outcome. Conclusion Laser Doppler imaging is accurate and effective in a paediatric population with a low-resolution fast-scan.

Estimation of vibration amplitude in Fourier domain optical coherence tomography interferometric signals from Doppler spectrum

In presented method combination of Fourier and Time domain detection enables to broaden the effective bandwidth for time dependent Doppler Signal that allows for using higher-order Bessel functions to calculate unambiguously the vibration amplitudes.

Doppler and Pathloss Characterization for Vehicle-to-Vehicle communications at 5.8 GHz

Due to significant increase in vehicular accident and traffic congestions, vehicle to vehicle (V2V) communication based on the intelligent transport system (ITS) was introduced. However, to carry out efficient design and implementation of a reliable vehicular communication systems,a deep knowledge of the propagation channel characteristics in different environments is crucial, in particular the Doppler and pathloss parameters. Therefore, this paper presents an empirical V2V channel characterization and measurement performed under realistic urban, suburban and highway driving conditions in Brisbane, Australia. Based on Lin Cheng statistical Doppler Model (LCDM), values for the RMS Doppler spread and coherence time due to time selective nature of V2V channels were presented. Also, based on Log-distance power law model, values for the mean pathloss exponent and the standard deviation of shadowing were reported for urban, suburban and highway environments. The V2V channel parameters can be useful to system designers for the purpose of evaluating, simulating and developing new protocols and systems.

Practical Algorithms For Mean Velocity Estimation In Pulse Doppler Weather Radars Using A Small Number Of Samples

Doppler weather radars with fast scanning rates must estimate spectral moments based on a small number of echo samples. This paper concerns the estimation of mean Doppler velocity in a coherent radar using a short complex time series. Specific results are presented based on 16 samples. A wide range of signal-to-noise ratios are considered, and attention is given to ease of implementation. It is shown that FFT estimators fare poorly in low SNR and/or high spectrum-width situations. Several variants of a vector pulse-pair processor are postulated and an algorithm is developed for the resolution of phase angle ambiguity. This processor is found to be better than conventional processors at very low SNR values. A feasible approximation to the maximum entropy estimator is derived as well as a technique utilizing the maximization of the periodogram. It is found that a vector pulse-pair processor operating with four lags for clear air observation and a single lag (pulse-pair mode) for storm observation may be a good way to estimate Doppler velocities over the entire gamut of weather phenomena.

Two Methods of Ambiguity Resolution in Pulse Doppler Weather Radars

A comparison is made of the performance of a weather Doppler radar with a staggered pulse repetition time and a radar with a random (but known) phase. As a standard for this comparison, the specifications of the forthcoming next generation weather radar (NEXRAD) are used. A statistical analysis of the spectral momentestimates for the staggered scheme is developed, and a theoretical expression for the signal-to-noise ratio due to recohering-filteringrecohering for the random phase radar is obtained. Algorithms for assignment of correct ranges to pertinent spectral moments for both techniques are presented.

Influence of validation schemes in a laser Doppler anemometer period timing device for frequency measurement

The short duration of the Doppler signal and noise content in it necessitate a validation scheme to be incorporated in the electronic processor used for frequency measurement, There are several different validation schemes that can be employed in period timing devices. A detailed study of the influence of these validation schemes on the measured frequency has been reported here. These studies were carried out by using a combination of a fast A/D converter and computer. Doppler bursts obtained from an air flow were digitised and stored on magnetic discs. Suitable computer programs were then used to simulate the performance of period timing devices with different validation schemes and the frequency of the stored bursts were evaluated. It is found that best results are obtained when the validation scheme enables frequency measurement to be made over a large number of cycles within the burst.

Simple period timing device for laser Doppler signals

A period timing device suitable for processing laser Doppler anemometer signals has been described here. The important features of this instrument are: it is inexpensive, simple to operate, and easy to fabricate. When the concentration of scattering particles is low the Doppler signal is in the form of a burst and the Doppler frequency is measured by timing the zero crossings of the signal. But the presence of noise calls for the use of validation criterion, and a 5–8 cycles comparison has been used in this instrument. Validation criterion requires the differential count between the 5 and 8 cycles to be multiplied by predetermined numbers that prescribe the accuracy of measurement. By choosing these numbers to be binary numbers, much simplification in circuit design has been accomplished since this permits the use of shift registers for multiplication. Validation accuracies of 1.6%, 3.2%, 6.3%, and 12.5% are possible with this device. The design presented here is for a 16-bit processor and uses TTL components. By substituting Schottky barrier TTLs the clock frequency can be increased from about 10 to 30 MHz resulting in an extension in the range of the instrument. Review of Scientific Instruments is copyrighted by The American Institute of Physics.