Separability of wave solutions in nonlinear brass instrument modelling.

Travelling wave representations of wave propagation are commonly employed in brass instrument modeling and have been extended to the nonlinear regimes. For the case of a real brass instrument, the assumptions that lead to the travelling wave solutions no longer strictly hold. The validity of these assumptions is investigated here with regard to two typical parts of brass instrument geometry. The first example shows that there is a small interaction between forwards and backwards travelling waves in a cylindrical tube. The second example highlights nonlinear backscattering of a traveling wave caused by variations in the tube cross-sectional area.

Semi-automatic measuring of arteriovenous relation as a possible silent brain infarction risk index in hypertensive patients. / Medición semiautomática de la relación arteriovenosa retiniana como posible marcador de riesgo de infarto cerebral silente en pacientes hipertensos.

OBJECTIVE: To evaluate the usefulness of a semiautomatic measuring system of arteriovenous relation (RAV) from retinographic images of hypertensive patients in assessing their cardiovascular risk and silent brain ischemia (ICS) detection. METHODS: Semi-automatic measurement of arterial and venous width were performed with the aid of Imedos software and conventional fundus examination from the analysis of retinal images belonging to the 976 patients integrated in the cohort Investigating Silent Strokes in Hypertensives: a magnetic resonance imaging study (ISSYS), group of hypertensive patients. All patients have been subjected to a cranial magnetic resonance imaging (RMN) to assess the presence or absence of brain silent infarct. RESULTS: Retinal images of 768 patients were studied. Among the clinical findings observed, association with ICS was only detected in patients with microaneurysms (OR 2.50; 95% CI: 1.05-5.98) or altered RAV (<0.666) (OR: 4.22; 95% CI: 2.56-6.96). In multivariate logistic regression analysis adjusted by age and sex, only altered RAV continued demonstrating as a risk factor (OR: 3.70; 95% CI: 2.21-6.18). CONCLUSIONS: The results show that the semiautomatic analysis of the retinal vasculature from retinal images has the potential to be considered as an important vascular risk factor in hypertensive population.

Linfoma no-Hodgkin primario del sistema nervioso central asociado a sida en un paciente con panuveítis por virus Epstein-Barr. Reporte clínico-patológico / Aids-related primary CNS non-Hodgkin's lymphoma in a patient with previous Epstein-Barr virus panuveitis. A clinico-pathological report

CASO CLÍNICO: Paciente con sida y uveítis por virus Epstein-Barr (VEB). La PCR de VEB fue positiva para humor acuoso y vítreo. Las cuantificaciones del virus fueron 56,602 × 106 copias/ml en humor vítreo, 173.400 copias/ml en sangre periférica y negativo en líquido cefalorraquídeo (LCR). El paciente desarrolló un linfoma no-Hodgkin (LNH) diagnosticado en la necropsia. CONCLUSIÓN: La uveítis por VEB es poco frecuente y para el diagnóstico es necesario realizar una PCR cuantitativa. Una elevada cantidad de DNA de VEB se ha asociado con mayor incidencia de LNH

CLINICAL CASE: Patient with AIDS and Epstein-Barr virus (EBV) uveitis. The PCR of the aqueous and vitreous humor was positive for EBV, and DNA quantification was 56.602 × 106 copies/ml in the vitreous humor, 173,400 copies/ml in the peripheral blood, and negative in the cerebrospinal fluid (CSF). The patient developed a non-Hodgkin's lymphoma (NHL), diagnosed in the autopsy. CONCLUSION: The EBV is a rare cause of uveitis and it may be necessary to perform a quantitative PCR to reach the diagnosis. High amounts of EBV DNA are associated with a greater incidence of NHL

[AIDS-related primary CNS non-Hodgkin's lymphoma in a patient with previous Epstein-Barr virus panuveitis. A clinico-pathological report]. / Linfoma no-Hodgkin primario del sistema nervioso central asociado a sida en un paciente con panuveítis por virus Epstein-Barr. Reporte clínico-patológico.

CLINICAL CASE: Patient with AIDS and Epstein-Barr virus (EBV) uveitis. The PCR of the aqueous and vitreous humor was positive for EBV, and DNA quantification was 56.602×10(6) copies/ml in the vitreous humor, 173,400 copies/ml in the peripheral blood, and negative in the cerebrospinal fluid (CSF). The patient developed a non-Hodgkin's lymphoma (NHL), diagnosed in the autopsy. CONCLUSION: The EBV is a rare cause of uveitis and it may be necessary to perform a quantitative PCR to reach the diagnosis. High amounts of EBV DNA are associated with a greater incidence of NHL.

Resonancia magnética nuclear con difusión: una nueva alternativa para valorar la respuesta patológica a la neoadyuvancia por cáncer de recto

Antecedentes: En la re-estadificación post-neoadyuvancia del cáncer de recto existen discrepancias clínico-patológicas y actualmente no existen métodos complementarios útiles para diferenciar la presencia o ausencia de tumor viable. Objetivo: Determinar el valor de la resonancia nuclear magnética con técnica de difusión en la identificación de la respuesta patológica completa luego de la neoadyuvancia y determinar su relación con el grado de respuesta clínica. Lugar de aplicación: Hospital Privado de la Comunidad. Diseño: Retrospectivo Población: 24 pacientes (10 mujeres), mediana de edad: 61 años, operados por cáncer de recto entre junio 2009 y enero 2011. Medidas de evaluación: De acuerdo a la respuesta clínica, fueron agrupados en Respondedores y No Respondedores. Todo valor de coeficiente de difusión aparente mayor a 1.2 x 10-3 mm²/seg fue considerado como respuesta patológica completa. Resultados: La mediana del coeficiente de difusión aparente fue de 1.1 (rango 0.7-2). En 4 casos (17%) se obtuvieron valores de coeficiente de difusión aparente mayores a 1.2 y fueron considerados como respuesta patológica completa. La mediana de coeficiente de difusión aparente en los casos con respuesta patológica completa fue significativamente mayor que la de los casos sin respuesta patológica completa (1.45 vs 1.01 respectivamente, p = 0.0002). De los 24 pacientes, 5 (21%) correspondieron al grupo de respuesta clínica. De ellos, 4 tuvieron una respuesta patológica completa. La resonancia nuclear magnética con técnica de difusión logró identificar estos 4 casos. En el paciente de este grupo que presentaba persistencia tumoral, el valor de coeficiente de difusión aparente fue de 1.1. De esta manera la resonancia nuclear magnética con técnica de difusión logró identificar al único caso en que se justificaría una cirugía radical. De los 19 pacientes que fueron considerados no respondedores, ninguno tuvo respuesta patológica completa. En todos estos casos los índices de coeficiente de difusión aparente fueron menores a 1.2 x 10-3 mm²/seg y en consecuencia no hubo ningún caso de falso negativo. Conclusiones: La resonancia nuclear magnética con técnica de difusión es una herramienta útil para la reestadificación post-neoayuvancia en cáncer de recto.

Background: There exist clinical-pathological discrepancies at the staging after neoadyuvant therapy of rectal cancer, and there are currently no additional useful methods to distinguish the presence or absence of viable tumor. Objective: To determine the value of magnetic resonance diffusion imaging technique in the identification of the pathological complete response after the neoadyuvant therapy and to determine its relationship with the degree of clinical response. Setting: Private Community Hospital. Design: Retrospective Population: 24 patients (10 women), median age: 61, operated on for rectal cancer from June 2009 to January 2011. Outcome measures: According to the clinical response, patients grouped in responders and non-responders. All apparent diffusion coefficient value greater than 1.2 x 10-3 mm²/seg was regarded as pathological response. Results: Median of apparent diffusion coefficient was 1.1 (0.7 and 2 range). In 4 cases (17 per cent) the apparent diffusion coefficient was greater than 1.2 x 10-3 mm², and were regarded as pathological complete. The medianm of apparent diffusion coefficien in cases with complete pathological response was significantly higher than the cases without pathological complete response (1.45 vs 1.01 respectively, p = 0.0002). Five out of 24 patients (21%) corresponded to the group in clinical response. Of these, 4 were n pathological compete response. The magnetic resonance imaging technique was able to identify these 4 cases. In the patient of this group which featured tumor persistence, the apparent diffusion coefficient value was 1.1. Thus the magnetic resonance diffusion imaging technique was able to identify the only case in which a radical surgery would be justified. Among the19 Patients were considered non-responders, none had pathological complete response. In all these cases apparent diffusion coefficient rates were lower to 1.2 x 10-3 mm²/ sec and therefore there was no case of false negative. Conclusions: The magnetic resonance diffusion technique is a useful tool for the staging after neoayuvant therapy in rectal cancer.