Experimental study of the ferroelastic phase transition in urea/n-heptadecane composite.

An experimental study of the ferroelastic phase transition in urea/n-heptadecane CO(NH2)2/C17H40 composite around the structural phase transition undergone by this crystal at 159 K is presented. The temperature dependence of the macroscopic spontaneous strain and the optical birefringence around this temperature has been determined. A phenomenological model limited to the hexagonal-orthorhombic change of the urea sublattice leads to a linear relation between these quantities and the phase transition entropy. The experimental data agree with this description exception made of the near vicinity of the phase transition, where the influence of the alkane chain ordering processes cannot be excluded.

Phase transitions in the urea/n-nonadecane system by calorimetric techniques.

A calorimetric study of urea/n-nonadecane, CO(NH(2))(2)/C(19)H(40), and the deuterated derivatives, CO(ND(2))(2)/C(19)D(40) and CO(NH(2))(2)/C(19)D(40), around the structural phase transition temperature is presented. For this purpose differential scanning (DSC), temperature-modulated (AC) and adiabatic calorimetry have been used and the obtained results are compared. Leaving apart the noticeable peak associated with the main phase transition at 158.5, 149.4 and 154 K respectively, small anomalies of the specific heat are found at lower temperatures and their corresponding entropic and enthalpic changes are reported. Heating and cooling experiments show the influence of the temperature rate and the thermal history on the detailed profile of the specific heat traces. The presence of thermal hysteresis and latent heat as a way to characterize the order of the phase transitions is discussed. Finally, a tentative approach to the urea and the alkyl chain contributions to the specific heat and their influence on the phase transition mechanisms is presented.

A novel stereotactic frame for real PET-guided biopsies: A preclinical proof-of-concept.

PURPOSE: To design, build and test a stereotactic device that allows PET image-guided biopsies to be performed. METHODS: An initial prototype consisting of four main pieces, one of which contains radioactive markers to make it visible in the PET images, was built using a 3D printer. Once the device is mounted, a spherical coordinate system is built with the entrance needle point in the skin as the origin of coordinates. Two in-house software programs, namely getCoord.ijm, which obtains the spherical coordinates of the tumour tissue to be biopsied, and getNeedle.ijm, which virtualizes the inner needle tip once the puncture has taken place, were written. This prototype was tested on an FDG-doped phantom to characterize both the accuracy of the system and the procedure time. RESULTS: Up to 11 complete biopsy procedures were conducted. The mean total procedure time was less than 20min, which is less than the procedure time of conventional standard CT-guided biopsies. The overall accuracy of the system was found to be 5.0±1.3mm, which outperforms the criterion used in routine clinical practice when targeting tumours with a diameter of 10mm. CONCLUSIONS: A stereotactic frame to conduct real PET image-guided biopsies has been designed and built. A proof-of-concept was performed to characterize the system. The procedure time and accuracy of the system were found to meet the current needs of physicians performing biopsies.

Identification of low variability textural features for heterogeneity quantification of 18F-FDG PET/CT imaging.

OBJECTIVE: To identify those textural features that are insensitive to both technical and biological factors in order to standardise heterogeneity studies on 18F-FDG PET imaging. MATERIALS AND METHODS: Two different studies were performed. First, nineteen series from a cylindrical phantom filled with different 18F-FDG activity concentration were acquired and reconstructed using three different protocols. Seventy-two texture features were calculated inside a circular region of interest. The variability of each feature was obtained. Second, the data for 15 patients showing non-pathological liver were acquired. Anatomical and physiological features such as patient's weight, height, body mass index, metabolic active volume, blood glucose level, SUV and SUV standard deviation were also recorded. A liver covering region of interest was delineated and low variability textural features calculated in each patient. Finally, a multivariate Spearman's correlation analysis between biological factors and texture features was performed. RESULTS: Only eight texture features analysed show small variability (<5%) with activity concentration and reconstruction protocol making them suitable for heterogeneity quantification. On the other hand, there is a high statistically significant correlation between MAV and entropy (P<0.05). Entropy feature is, indeed, correlated (P<0.05) with all patient parameters, except body mass index. CONCLUSIONS: The textural features that are correlated with neither technical nor biological factors are run percentage, short-zone emphasis and intensity, making them suitable for quantifying functional changes or classifying patients. Other textural features are correlated with technical and biological factors and are, therefore, a source of errors if used for this purpose.

[Pleural effusion due to Listeria monocytogenes. A case report and review of the literature]. / Derrame pleural por Listeria monocytogenes. Presentación de un caso y revisión de la literatura.

The infection caused by Listeria monocytogenes is a relatively common condition in immunosuppressed patients. The most frequent presentation in adults are sepsis and meningitis. Pleural fluid infection due to this pathogen is a rare finding in the literature. Most cases are found in immunosuppressed patients, particularly in those with haematologic malignancies. We report one case of pleural fluid infection due to Listeria monocytogenes in a patient with hepatic cirrhosis (the third case in the literature). We also review the seventeen cases previously reported and describe the clinical manifestations, its immunosuppression states relationship, the treatment of choice and the mortality.

[Epicutaneous test with inhalers in the study of atopic dermatitis]. / Test epicutáneos con inhalantes en el estudio de la dermatitis atópica.

In some 80% of patients with atopic dermatitis, the presence of specific IgE is found when facing food or environmental allergens. It has also been demonstrated in a sub-group of patients with atopic dermatitis that the dermatitis lesions are exacerbated following the ingestion or inhalation of allergens, and that they improve with reduction of exposure to allergens. Although the prick method and the determination of specific IgE in serum are highly sensitive techniques, epicutaneous tests, applying the allergen directly to the skin, might be the ideal diagnostic method since they reproduce the characteristic inflammatory response of the disease on the affected organ itself, the skin. However, there is great variability in the results obtained through epicutaneous tests with aeroallergens, basically due to methodological differences, which are reviewed in this paper. Finally, we present the results of carrying out epicutaneous tests with inhalant allergens on our patients with atopic dermatitis and controls, where some 27% of positive patches were obtained, basically with acari, and in those patients with more severe dermatitis, without there being complete concordance with the prick technique. For this reason, the epicutaneous test appears to be a method of allergological diagnosis that might be useful and complementary to the routine techniques of the prick method and the determination of specific IgE in serum, but it is in need of suitable standardization.

[Inhalation techniques in the treatment of asthma]. / Técnicas de inhalación en el tratamiento del asma.

In the pharmacological treatment of asthma, the most suitable way is by inhalation, since this enables us to achieve a greater concentration of medicine in the affected organ than systemic medication, and besides the latter's secondary effects are minimized. The suitable use of inhalers and hence their efficacy depends on very different factors. Some of those of a merely technical kind are as follows: A suitable volume of inhalation. The rhythm of inhalation. The length of the inspiratory apnea following administration of the medicine. The coordination between the inspiration of the aerosol and activation of the device, in the case of the metered dose inhaler (MDI). One of the reasons for the incorrect use of MDI aerosols is the lack of coordination between activation of the device and inspiration. This has led to the design of different devices that avoid the need for this coordination, such as: inhalation chambers and devices for inhaling dry dust. It has also been suggested in the literature that the causes of these mistakes are to be found in the health professionals not knowing, or not suitably teaching the patients how to handle the devices. In spite of being designed to facilitate correct administration, suitable knowledge of the technique of their use by the patient is required.

Localización atípica de metástasis de carcinoma de ovario detectada con 18F-FDG PET/TC / Atypical location of metastatic ovarian carcinoma detected by 18F-FDG PET/CT

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Identification of low variability textural features for heterogeneity quantification of 18F-FDG PET/CT imaging / Identificación de texturas de baja variabilidad para la cuantificación de la heterogeneidad en imagen 18F-FDG PET/TC

Objective. To identify those textural features that are insensitive to both technical and biological factors in order to standardise heterogeneity studies on 18F-FDG PET imaging. Materials and methods. Two different studies were performed. First, nineteen series from a cylindrical phantom filled with different 18F-FDG activity concentration were acquired and reconstructed using three different protocols. Seventy-two texture features were calculated inside a circular region of interest. The variability of each feature was obtained. Second, the data for 15 patients showing non-pathological liver were acquired. Anatomical and physiological features such as patient's weight, height, body mass index, metabolic active volume, blood glucose level, SUV and SUV standard deviation were also recorded. A liver covering region of interest was delineated and low variability textural features calculated in each patient. Finally, a multivariate Spearman's correlation analysis between biological factors and texture features was performed. Results. Only eight texture features analysed show small variability (<5%) with activity concentration and reconstruction protocol making them suitable for heterogeneity quantification. On the other hand, there is a high statistically significant correlation between MAV and entropy (P<0.05). Entropy feature is, indeed, correlated (P<0.05) with all patient parameters, except body mass index. Conclusions. The textural features that are correlated with neither technical nor biological factors are run percentage, short-zone emphasis and intensity, making them suitable for quantifying functional changes or classifying patients. Other textural features are correlated with technical and biological factors and are, therefore, a source of errors if used for this purpose (AU)

Objetivo. Identificar las texturas que son independientes de los factores técnicos y biológicos en imagen PET con 18F-FDG con el fin de estandarizar la heterogeneidad en imagen PET. Material y métodos. Se realizaron 2 estudios. En primer lugar, se estudió la variabilidad de 72 parámetros texturales en una región de interés circular en el interior de un maniquí cilíndrico, con 19 concentraciones de actividad y 3 protocolos de reconstrucción diferentes. A continuación, se estudió una población de 15 pacientes sin captaciones hepáticas. De cada paciente se registraron el peso, altura, índice de masa corporal, volumen metabólico activo, niveles de glucosa en sangre, SUV y desviación estándar de SUV. Se obtuvieron las texturas de baja variabilidad de una región de interés centrada en hígado. Finalmente, se realizó un análisis de correlación multivariado de Spearman entre los factores biológicos y los parámetros texturales. Resultados. Solo 8 parámetros texturales muestran baja variabilidad (<5%) con la concentración de actividad y el protocolo de reconstrucción, haciéndolos adecuados para cuantificar la heterogeneidad de la región captante. Por otro lado, existe una correlación estadísticamente significativa entre el volumen metabólico activo y la entropía (p<0,05). La entropía está, además, correlacionada con los demás parámetros, excepto el índice de masa corporal. Conclusiones. Las únicas texturas que no están correlacionadas con ninguno de los parámetros anatómicos o fisiológicos son run percentage, short-zone emphasis e intensidad, siendo estas las más adecuadas para realizar análisis cuantitativos de heterogeneidades mediante parámetros de textura. Otras texturas están relacionadas con factores técnicos y biológicos y, por tanto, constituyen una fuente de errores cuando se utilizan para este fin (AU)

Técnicas de inhalación en el tratamiento del asma / Inhalation techniques in the treatment of asthma

En el tratamiento farmacológico del asma, la vía más adecuada es la inhalatoria, ya que nos permite alcanzar una mayor concentración de medicamento en el órgano de choque que la medicación sistémica, y además se minimizan los efectos secundarios de esta última. El uso adecuado de los inhaladores y con ello su eficacia depende de muy diversos factores. Entre los de índole meramente técnica, algunos de ellos son: - Un adecuado volumen de inhalación.- El ritmo de inhalación.- La duración de la apnea inspiratoria tras la administración del medicamento.- La coordinación entre la inspiración del aerosol y la activación del dispositivo, en el caso del MDI. Uno de los motivos de uso incorrecto de los aerosoles MDI es la falta de coordinación entre la activación del dispositivo y la inspiración. Ello ha motivado el diseño de diferentes dispositivos que obvien la necesidad de esta coordinación como son: las cámaras inhalatorias y los dispositivos para inhalar polvo seco. También se sugiere en la literatura que las causas de estos errores son motivados porque los profesionales sanitarios no conocen o no enseñan adecuadamente el manejo de los dispositivos a los pacientes. A pesar de estar diseñados para facilitar la correcta administración, exigen un conocimiento adecuado de la técnica de uso por parte del paciente (AU)

Test epicutáneos con inhalantes en el estudio de la dermatitis atópica / Epicutaneous test with inhalers in the study of atopic dermatitis

En un 80 por ciento de pacientes con dermatitis atópica se demuestra la presencia de IgE específica frente a alergenos alimentarios o ambientales. También se ha demostrado la exacerbación de las lesiones de la dermatitis tras ingestión o inhalación de alergenos y su mejoría al reducir la exposición alergénica en un subgrupo de pacientes con dermatitis atópica. Aunque el prick y la determinación de IgE específica en suero son técnicas muy sensibles, las pruebas epicutáneas aplicando el alergeno directamente en la piel podrían ser el método diagnóstico ideal ya que reproducen la respuesta inflamatoria característica de la enfermedad en el propio órgano de choque que es la piel. Sin embargo, existe gran variabilidad en los resultados obtenidos mediante pruebas epicutáneas con aeroalergenos, debido fundamentalmente a diferencias metodológicas, que se revisan en este trabajo. Por último, presentamos los resultados de realizar pruebas epicutáneas con alergenos inhalantes a nuestros pacientes con dermatitis atópica y controles, obteniendo un 27 por ciento de parches positivos, fundamentalmente con ácaros y en aquellos pacientes con dermatitis más grave sin que exista una completa concordancia con la técnica del prick. Por ello, las pruebas epicutáneas parecen un método de diagnóstico alergológico que puede ser útil y complementario a las técnicas de rutina como el prick o la determinación de IgE específica en suero, pero queda pendiente su adecuada estandarización (AU)

Eosinofilia y diarrea secundarias a enalapril: a propósito de un caso / No disponible

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Hiperplasia gingival secundaria a amlodipino: a propósito de un caso / Gingival hyperplasia secondary to amlodipine: a case report

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Derrame pleural por Listeria monocytogenes. Presentación de un caso y revisión de la literatura / Pleural fluid infection caused by listeria monocytogenes: case report and literature review

La infección por Listeria monocytogenes es relativamente frecuente en pacientes inmunodeprimidos, la sepsis y la afectación neuromeníngea son las formas de presentación más habituales. La infección de la cavidad pleural por este germen es una entidad escasamente descrita en la literatura, en la mayoría de los casos se presenta en pacientes inmunodeprimidos, sobre todo con enfermedades hematológicas malignas. Presentamos un caso de infección pleural por Listeria monocytogenes en un paciente con cirrosis hepática (tercer caso descrito) y revisamos diecisiete casos previos analizando las formas de presentación, su relación con estados de inmunodepresión, tratamiento de elección y mortalidad (AU)