Histoplasma capsulatum Pacemaker-related Endocarditis Presenting as Endogenous Endophthalmitis.

PURPOSE: To report a unique case of pacemaker-related infective endocarditis manifesting as endogenous endophthalmitis with chorioretinitis secondary to Histoplasma capsulatum. METHOD: Case Report. RESULTS: A 75-year-old man was diagnosed with blood culture-negative infective endocarditis and was admitted with deteriorating vision and ocular inflammation. Examination of the eye indicated significant vitreous inflammation and retinitis. Vitreous cultures were negative, but universal fungal PCR of the vitreous fluid was positive for Histoplasma capsulatum. Histopathology of the fibrous cuff around the extracted right atrial lead demonstrated hyphal and yeast forms and PCR of this material identified Histoplasma capsulatum. Despite aggressive antifungal and surgical treatment, the eye became phthisical. CONCLUSION: We highlight the importance of considering Histoplasma capsulatum in the differential diagnosis of endogenous endophthalmitis, particularly among patients from endemic areas who present with possible endovascular infection.

Early post-transplant cutaneous bacillary angiomatosis in a kidney recipient: Case report and review of the literature.

Bacillary angiomatosis (BA) is an uncommon systemic disease caused by Bartonella henselae (BH) or Bartonella quintana (BQ) that occurs primarily in immunocompromised hosts. Few cases of BA recipients have been reported in adult solid transplant recipients over the years, with most cases presenting years after transplant. We describe a case of a kidney transplant recipient who developed cutaneous BA very early in the post-transplant period despite not having any exposures. Retrospective testing of donor and recipient's serum was performed and raised the concern for possible donor-derived infection. A literature review encompassing 1990 to present was also performed in order to better understand the clinical presentation, diagnostics and therapeutic approach of this unusual disease. Combined serology, histopathology and molecular testing (polymerase chain reaction [PCR]) were useful in diagnosing BA in our patient as serology alone might be unreliable. Macrolides or doxycycline for at least 3 months is the recommended therapeutic strategy; however, the optimal duration of treatment is not well established in transplant recipients. In our patient, we decided to use doxycycline for 1 year due to gradual resolution of lesions and ongoing immunosuppression. Patient responded successfully without any documented relapse.

Magnetorheology: a review.

Magnetic Soft Matter is a rapidly evolving discipline with fundamental and practical interest. This is due to the fact that its physical properties can be easily controlled through external magnetic fields. In this review paper, we revisit the most recent progress in the field (since 2010) emphasizing the rheological properties of these fascinating materials. New formulations and flow kinematics are discussed. Also, new members are integrated into the long-lived magnetorheology family and suggestions are provided for future development.

Tocilizumab therapy in 5 solid and composite tissue transplant recipients with early ARDS due to SARS-CoV-2.

There are emerging data depicting the clinical presentation of coronavirus disease 19 (COVID-19) in solid organ transplant recipients but negligible data-driven guidance on clinical management. A biphasic course has been described in some infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), beginning with a flu-like illness followed by an intense inflammatory response characterized by elevated c-reactive protein (CRP), interleukin 6 (IL-6), and acute respiratory distress syndrome (ARDS) associated with high mortality. The exuberant and possibly dysregulated immune response has prompted interest in therapeutic agents that target the cytokines involved, particularly IL-6. Tocilizumab is an IL-6 receptor antagonist with a record of use for a variety of rheumatologic conditions and cytokine release syndrome due to chimeric antigen receptor T-cell therapy but experience in solid organ and composite tissue transplant recipients (SOT/CTTRs) with SARS-CoV-2-related ARDS has not been previously reported in detail. We present the clinical course of 5 SOT/CTTRs with SARS-CoV-2-related ARDS that received tocilizumab with favorable short-term outcomes in 4. Responses were characterized by reductions in CRP, discontinuation of vasopressors, improved oxygenation and respiratory mechanics, and variable duration of ventilator support. Four bacterial infections occurred within 2 weeks of tocilizumab administration. We discuss safety concerns and the need for randomized comparative trials to delineate tocilizumab's clinical utility in this population.

Magnetorheology in saturating fields.

Understanding magnetorheology in saturating fields is crucial for success in high torque applications. In this paper we use numerical computations, analytical developments, and experimental data (using a double-gap magnetocell) to study the saturation behavior of model magnetorheological fluids for different particle loadings. Numerical calculations demonstrate a nonlinear dependence of both shear and normal stresses with particle concentration in contrast with analytical predictions. These predictions are in very good agreement with numerical calculations at low volume fractions when the interchain interactions can be safely neglected. Numerical calculations for the (yield) shear stress overestimate experimental data for small and medium concentrations. However, a reasonably good qualitative agreement is found for the larger particle loadings. Normal stresses are extraordinarily sensitive to the particular microstructure; experiments suggest sample dilatation in good agreement with simulations in lattices with a body-centered basis.

Yielding behavior of model magnetorheological fluids.

The yielding behavior of magnetorheological fluids is revisited through the use of finite element method calculations on model structures and carefully conducted experiments in a magnetorheometer. Model structures investigated in this work are monoclinic lattices with simple and body centered bases. From the simulation point of view we emphasize the influence of the interparticle gap separation. From the experimental point of view we elucidate the importance of the magnetic field application and the occurrence of slip at the confining surfaces. Simulations demonstrate that the yield stress τ0 scales with the interparticle center-to-center distance h as τ0/M2 ∝ h-6 where M is the particle magnetization. A good agreement is found when the simulated yield stresses are compared with the experimental ones, independent of the particular packing and interparticle gap.

Aggregation kinetics of carbonyl iron based magnetic suspensions in 2D.

We investigate the (irreversible) two-dimensional aggregation kinetics of dilute non-Brownian magnetic suspensions in rectangular microchannels using video-microscopy, image analysis and particle-level dynamics simulations. Special emphasis is given to carbonyl iron suspensions that are of interest in the formulation of magnetorheological fluids. The results are compared to non-Brownian suspensions of magnetic latexes. We demonstrate that both suspensions follow a deterministic aggregation process. Furthermore, experimental and simulation aggregation curves can be collapsed onto a master curve when using the appropriate scaling time (∝λ-1ϕ2D-2.5) as a function of only two dimensionless numbers: the lambda ratio (λ) and the particle surface fraction (ϕ2D).

Colloidal Stability and Magnetic Field-Induced Ordering of Magnetorheological Fluids Studied with a Quartz Crystal Microbalance.

This work proposes the use of quartz crystal microbalances (QCMs) as a method to analyze and characterize magnetorheological (MR) fluids. QCM devices are sensitive to changes in mass, surface interactions, and viscoelastic properties of the medium contacting its surface. These features make the QCM suitable to study MR fluids and their response to variable environmental conditions. MR fluids change their structure and viscoelastic properties under the action of an external magnetic field, this change being determined by the particle volume fraction, the magnetic field strength, and the presence of thixotropic agents among other factors. In this work, the measurement of the resonance parameters (resonance frequency and dissipation factor) of a QCM are used to analyze the behavior of MR fluids in static conditions (that is, in the absence of external mechanical stresses). The influence of sedimentation under gravity and the application of magnetic fields on the shifts of resonance frequency and dissipation factor were measured and discussed in the frame of the coupled resonance produced by particles touching the QCM surface. Furthermore, the MR-fluid/QCM system has a great potential for the study of high-frequency contact mechanics because the translational and rotational stiffness of the link between the surface and the particles can be tuned by the magnetic field.

[Acute respiratory distress syndrome due to Clostridium difficile colitis: a case report and review of the literature]. / Síndrome de distress respiratorio agudo debido a colitis por Clostridium difficile: reporte de caso y revisión de la literatura.

Clostridium difficile is a major cause of antibiotic-associated diarrhea. We report a patient with complicated Clostridium difficile infection (CDI) who developed rapidly progressive acute respiratory distress syndrome (ARDS), for which CDI was the only identifiable source. CDI should be considered in the differential diagnosis for anyone with diarrhea who presents especially in high-risk groups such as the elderly, hospitalized patients, or those who have had a history of CDI.

Acute respiratory distress syndrome due to Clostridium difficile colitis: a case report and review of the literature / Síndrome de distress respiratorio agudo debido a colitis por Clostridium difficile: reporte de caso y revisión de la literatura

Clostridium difficile is a major cause of antibiotic-associated diarrhea. We report a patient with complicated Clostridium difficile infection (CDI) who developed rapidly progressive acute respiratory distress syndrome (ARDS), for which CDI was the only identifiable source. CDI should be considered in the differential diagnosis for anyone with diarrhea who presents ARDS, especially in high-risk groups such as the elderly, hospitalized patients, or those who have had a history of CDI.

El Clostridium difficile es una de las causas más frecuentes de diarreas asociadas a antibióticos. Reportamos un paciente con infección por Clostridium difficile complicada (CDI) que desarrolló rápida y progresivamente un síndrome de distress respiratorio agudo (ARDS), del cual el CDI fue la fuente única identificable. El CDI debe considerarse en el diagnóstico diferencial de cualquier persona con diarrea que presenta ARDS, especialmente en los grupos de alto riesgo como los ancianos, pacientes hospitalizados o aquellos que han tenido historia precia de DCI.