First Case Described in the Medical Literature: Male Urethral Sarcoidosis. Description of a Case and Review of the Literature

Objective: Although the sarcoidosis is a multisystemic disease that theoretically can affect almost any organ, the presence of sarcoidosis in the male urethra has not been described in the medical literature. We present the first male case of urethral sarcoidosis. Method: A 46 years old male undergoing follow up due to lower urinary tract symptoms was diagnosed of endobronchial sarcoidosis during the preoperative study for internal urethrotomy. After surgery, he presented clinical improvement for one year. Given the worsening, a new internal urethrotomy was tried. As it was impossible due to complexity they took a biopsy of the urethra. The pathology report described non-caseating granulomas compatible with sarcoidosis. After that, medical and endoscopic management of the urethral sarcoidosis was attempted. As it didn't achieve an adequate control, the patient was derivate to the "complex urethral unit" of the Cruces University Hospital. Once it was valuated, it was decided to start immunotherapy and subsequently an urethroplasty with a double oral mucosa graft was performed. Outcomes: During the postoperative period, a urethral catheter was maintained for two weeks. It was removed after no urinary leakage was observed in de cystourethrography. After that the patient remains with good evolution until today. Conclusions: Urethral affectation by sarcoidosis is a therapeutic challenge itself. For a better symptom control and to reduce the recurrences, a dual approach using systemic treatment in combination with local surgical treatment seems necessary (AU)

Objetivo: Pese a que la sarcoidosis es una enfermedad multisistémica que teóricamente puede afectar a casicualquier órgano, no ha sido descrita en la literatura médicala presencia de sarcoidosis en uretra masculina. Presentamos el diagnóstico y tratamiento del primer caso masculinode sarcoidosis uretral.Método: Varón de 46 años en seguimiento por clínicamiccional de vaciado al que se le diagnosticó de sarcoidosis endobronquial durante el estudio preoperatorio para larealización de una uretrotomía interna. Tras la intervenciónpresentó mejoría clínica durante un año. Ante el empeoramiento, se intentó repetir una nueva uretrotomía internasiendo esta imposible y decidiéndose realizar una biopsia.El informe anatomopatológico describió granulomas no caseificantes compatibles con sarcoidosis. Posteriormente seintentó un manejo médico y endoscópico de la sarcoidosis uretral que no logró un adecuado control por lo que sederivó a la unidad de uretra compleja del Hospital Universitario Cruces. Ante los hallazgos se decidió comenzar coninmunoterapia y posteriormente se realizó una uretroplastiacon doble injerto de mucosa oral.Resultado: Durante el postoperatorio se mantuvo unasonda uretral durante dos semanas. Posteriormente se retirótras la realización de una cistouretrografía miccional seriada donde no se apreciaba fuga urinaria permaneciendo elpaciente con buena evolución hasta hoy en día.Conclusiones: La afectación uretral por sarcoidosissupone actuar ante una patología que de por sí es un retoterapéutico. Para un mejor control sintomatológico y reducir las recidivas parece necesario un abordaje doble mediante un tratamiento sistémico farmacológico en combinación con tratamiento quirúrgico local (AU)

Periodicity characterization of the nonlinear magnetization dynamics.

In this work, we study numerically the periodicity of regular regions embedded in chaotic states for the case of an anisotropic magnetic particle. The particle is in the monodomain regime and subject to an applied magnetic field that depends on time. The dissipative Landau-Lifshitz-Gilbert equation models the particle. To perform the characterization, we compute several two-dimensional phase diagrams in the parameter space for the Lyapunov exponents and the isospikes. We observe multiple transitions among periodic states, revealing complex topological structures in the parameter space typical of dynamic systems. To show the finer details of the regular structures, iterative zooms are performed. In particular, we find islands of synchronization for the magnetization and the driven field and several shrimp structures with different periods.

Chaotic dynamics of a magnetic nanoparticle.

We study the deterministic spin dynamics of an anisotropic magnetic particle in the presence of a magnetic field with a constant longitudinal and a time-dependent transverse component using the Landau-Lifshitz-Gilbert equation. We characterize the dynamical behavior of the system through calculation of the Lyapunov exponents, Poincaré sections, bifurcation diagrams, and Fourier power spectra. In particular we explore the positivity of the largest Lyapunov exponent as a function of the magnitude and frequency of the applied magnetic field and its direction with respect to the main anisotropy axis of the magnetic particle. We find that the system presents multiple transitions between regular and chaotic behaviors. We show that the dynamical phases display a very complicated structure of intricately intermingled chaotic and regular phases.

Magnetic phase diagrams of barcode-type nanostructures.

The magnetic configurations of barcode-type magnetic nanostructures consisting of alternate ferromagnetic and nonmagnetic layers arranged within a multilayer nanotube structure are investigated as a function of their geometry. Based on a continuum approach we have obtained analytical expressions for the energy which lead us to obtain phase diagrams giving the relative stability of characteristic internal magnetic configurations of the barcode-type nanostructures.