Use of a new hemicellulose dressing (Veloderm) for the treatment of split-thickness skin graft donor sites A within-patient controlled study

A multi-centre, open, within-patient controlled study was performed on 23 adult burnt patients to investigate the effectiveness, safety and tolerability of Veloderm^® in comparison with Algisite M™ and Jaloskin^® in split-thickness skin graft donor site care. The areas dressed with Veloderm^® completely healed within 10–13 days in a significant higher proportion than the other two dressings (47.6% for Veloderm^® versus 26.3% for Algisite M™ and 10% for Jaloskin^®, P < 0.03), showing during the whole study less incidence of exudates and of peri-lesional erythema. The aesthetic outcome of the treated lesions after healing was significantly better for Veloderm^® (P = 0.0016). Veloderm^® and Jaloskin^® required very few renewals of the medication during the first week of treatment, while Algisite M™ needed several multiple re-dressings. Veloderm^® was judged better than the other two treatments as far as the acceptability (P < 0.001), ease of use (P < 0.001) and efficacy (P < 0.00001). Both pain during application or at removal of dressings and local infections were negligible with all treatments. No scars were formed in any skin donor site. In conclusion Veloderm^® is a safe and effective dressing for the re-epithelialization of the skin graft donor sites: it showed higher activity than the other two compared dressings.     

Dermatological aspects of cerebrovascular diseases

Neurological symptoms are sometimes triggered by the same mechanisms as are skin manifestations. They include genetic conditions like the epidermal nevus syndrome, the Sneddon syndrome, Fabry disease and others, as well as certain inflammatory disorders like erythematous lupus, Bechet disease. Basically all conditions giving rise to anticoagulation processes may cause simultaneously neurological and cutaneous manifestations. Cerebrovascular stroke is the third most common condition of death in the developed world after cancer and ischemic heart disease. The mechanisms responsible for development of skin manifestations in patients afflicted by stroke are shortly reviewed. Stroke may also influence the already existent skin diseases.     

Prediction of clinical outcomes in Crohn’s disease by using confocal laser endomicroscopy: results from a prospective multicenter study

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Tenofovir-based rescue therapy for advanced liver disease in 6 patients coinfected with HIV and hepatitis B virus and receiving lamivudine.

We summarize the clinical history and laboratory results following the introduction of tenofovir among 6 patients coinfected with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) who presented with severe liver disease while receiving lamivudine-based highly active antiretroviral therapy. In all cases, the introduction of tenofovir led to a sustained undetectable HBV and HIV loads, with marked clinical and laboratory improvement in liver function. We provide supporting evidence for the role of tenofovir in the management of advanced HBV infection in HIV-positive patients after the development of lamivudine resistance.     

ALK-negative lung inflammatory myofibroblastic tumor in a young adult: A case report and literature review of molecular alterations

Rationale:Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor that is prevalent among children and adolescents. Surgery is the most important therapeutic approach for IMT and complete resection is recommended. Although 50% of IMTs show anaplastic lymphoma kinase (ALK) rearrangements, crizotinib has proven an effective therapeutic approach. However, the genetic landscape of this tumor is still not fully understood and treatment options are limited, especially in the majority of ALK-negative tumors.Patient concerns:We describe the clinical case of a healthy 18-year-old female in whom a pulmonary nodule was incidentally detectedDiagnoses:Following a small increase in the size of the nodule, the patient underwent both ¹⁸FDG-PET/CT and ⁶⁸Ga-PET/CT, resulting in a suspicion of bronchial hamartoma.Interventions:The patient underwent surgery and a salivary gland-like lung tumor was diagnosed.Outcomes:After surgery, the patient was referred to our cancer center, where a review of the histology slides gave a final diagnosis of ALK-negative lung IMT. Given the histology, it was decided not to administer adjuvant therapy and the patient was placed in a 3-monthly follow-up program. The patient is still disease-free 2 years post-surgery.Lessons:Although there is no standard of care for the treatment of IMT, identifying genomic alterations could help to redefine the management of patients with negative-ALK disease. Our review of the literature on IMT and other kinase fusions revealed, in addition to ALK rearrangements, the potential association of ROS1, NTRK, RET, or PDGFR beta alterations with the tumor.     

The effect of alcohols as the third component on diffusion in mixtures of aromatics and ketones

With laboratory and numerical work, we demonstrate that one of the main diffusion coefficients and the smaller eigenvalue of the Fick diffusion matrix are invariant to the number of methylene groups of the alcohol in ternary mixtures composed of an aromatic (benzene), a ketone (acetone) and one of three different alcohols (methanol, ethanol or 2-propanol). A critical analysis of the relationship between the kinetic and thermodynamic contributions to the diffusion coefficients allows us to explain this intriguing behaviour of this class of mixture. These findings are reflected by the diffusive behaviour of the according binary subsystems. Our approach provides a promising systematic framework for future investigations into the important and challenging problem of transport diffusion in multicomponent liquids.

The Fick diffusion coefficient matrix of three ternary mixtures composed of an aromatic (benzene), a ketone (acetone) and one of three different alcohols (methanol, ethanol or 2-propanol) is investigated with laboratory and numerical work.

Multicomponent diffusion plays a crucial role in various natural and industrial processes involving mass transfer.^1–3 Liquids appearing in nature and technical applications are essentially multicomponent. However, only data on binary diffusion coefficients are relatively abundant because the diffusion behavior of ternary and higher mixtures is much more complex.^4,5 Describing the isothermal–isobaric diffusion of a ternary mixture by Fick’s law requires four different diffusion coefficients that are composition dependent. The presence of cross diffusion coefficients aggravates the interpretation and data processing in experimental work, resulting in large uncertainties.^6,7 Thus, efforts are being made to develop new methods for analysis of multicomponent diffusion explicitly addressing various degrees of complexity.^8–10 Predictive equations for multicomponent diffusion of liquids mostly rely on extensions of the Darken relation,^11–13 which is only valid for ideal mixtures.¹⁴ The underlying physical phenomena in non-ideal mixtures are not well understood and the lack of experimental data impedes the development and verification of new predictive equations.The objective of this study was not only to measure and predict the Fick diffusion coefficient matrix for a series of ternary liquid mixtures, rather, the emphasis lied on understanding common features and whether they can be related to the behavior of the pure components and binary subsystems. Three ternary mixtures that are composed of organic compounds were selected, i.e. an aromatic, a ketone and an alcohol. Throughout, the first two components were benzene (1) and acetone (2) and the third component was one of the alcohols, methanol, ethanol or 2-propanol. For each mixture, nine state points along a composition path with a constant content of benzene, x₁ = 0.33 mol mol⁻¹, were studied under ambient conditions (298.15 K and 0.1 MPa). Seven of the state points were ternary mixtures and two were binary subsystems. To obtain reliable results for the Fick diffusion coefficient matrix, two complementary approaches were used, i.e. experiments and predictive molecular simulations. This combination allows for a critical analysis and leads to a deeper understanding of the underlying phenomena.^14,15The Taylor dispersion technique was utilized for the experiments.^16,17 In this method, a small quantity of mixture with a slightly different composition is injected into a laminar stream. It disperses due to convection and diffusion while flowing through a capillary tube and the refractive index is measured at its end to sample the concentration distribution. We have used the same apparatus as in previous works.^6,7 The Fick diffusion matrix is obtained by fitting working equations to the measured signal, i.e. the Taylor peak. The mathematical model of the Taylor dispersion technique was originally developed on the basis of Fick’s law in the volume reference frame. In a ternary mixture, two molar fluxes J^v_i relative to a volume averaged velocity are related to gradients of molar concentration ∇C_i with four diffusion coefficients D^v_ij. Alternatively, fluxes expressed in the molar reference frame J_i are relative to a molar averaged velocity and the mole fraction gradients ∇x_i act as a driving force1with molar density ρ. The fluxes of all three components are constrained by ΣJ_i = 0. The main diffusion coefficients D₁₁ and D₂₂ relate the flux of one component to its own mole fraction gradient and the cross diffusion coefficients D₁₂ and D₂₁ describe the coupling of the flux of one component with the gradient of the other. The third component does not appear in eqn (1) explicitly, but in general it affects all four diffusion coefficients. The transformation of experimental data from the volume to the molar reference frame (D^v_ij to D_ij) could be done here on the basis of the pure component volumes (see the ESI^†).Equilibrium molecular dynamics (MD) simulations were employed in this work, allowing for examination at the microscopic scale. The underlying molecular models were rigid, non-polarizable force fields of united atom type, consisting of a varying number of Lennard–Jones, point charge, dipole and quadrupole sites (see the ESI^†). Note that the force field parameters were adjusted to pure fluid properties only so that all simulation results for the mixtures are strictly predictive. Diffusion coefficients were sampled with the Green–Kubo formalism, based on integrated correlation functions of net velocities of the contained species.^11,15 Thereby, phenomenological coefficients Δ_ij were obtained, associating the diffusive fluxes with the chemical potential gradients ∇μ_i2with gas constant R and temperature T. Fluxes J_i correspond to the molar reference frame as in eqn (1).The diffusion coefficients from experiment and simulation are related to different driving forces so that the chemical potential gradients have to be transformed to the mole fraction gradients for their comparison.¹⁸ This transformation is contained in the thermodynamic factor matrix Γ3with the activity coefficient of species i being γ_i, which expresses the non-ideality of a mixture with respect to the composition. This relationship shows that the Fick diffusion coefficients are actually the product of two contributions, a kinetic Δ_ij and a thermodynamic Γ_ij. The separate observation of these two contributions promotes understanding of the underlying physical phenomena. In the present study, the thermodynamic factor was calculated using the Wilson excess Gibbs energy (g^E) model, using parameters fitted to experimental vapor–liquid equilibrium data of the binary subsystems (see the ESI^†). This combination of MD simulation results with a g^E model was successfully used in previous work to predict Fick diffusion coefficients, including several binary subsystems of the ternary mixtures studied here.¹⁹The four elements of the Fick diffusion coefficient matrix were determined for the three ternary mixtures, benzene + acetone + methanol/ethanol/2-propanol, for nine different compositions, each at ambient temperature and pressure.Results for the first main element of the diffusion matrix D₁₁, which relates the flux of benzene to its own mole fraction gradient, are shown in Fig. 1(a). The experimental data agree quantitatively with the molecular simulation data. D₁₁ increases with the acetone content in the ternary mixture. Since mixtures with a constant mole fraction of benzene (x₁ = 0.33 mol mol⁻¹) were studied throughout, the left edge of Fig. 1(a) corresponds to the binary limit of benzene + alcohol, while the right edge corresponds to that of benzene + acetone. Analysis of the ternary diffusive fluxes implies the following asymptotic behavior of the diffusion coefficients towards the binary limits:⁷ (i) at the infinite dilution limit, x₂ → 0, the ternary coefficient D₁₁ tends to the binary Fick diffusion coefficient of benzene + alcohol; (ii) at the other limit, x₃ → 0, D₁₁ − D₁₂ = D₂₂ − D₂₁ → D_bin (benzene + acetone) should hold. The present experimental and simulation results for D₁₁ are consistent with these asymptotic limits.Open in a separate windowFig. 1Top: The main Fick diffusion coefficient (molar reference frame) of benzene D₁₁ in the three ternary mixtures benzene (1) + acetone (2) + alcohol (3) at a constant benzene mole fraction x₁ = 0.33 mol mol⁻¹ from experiment (triangles) and MD simulation combined with the Wilson g^E model (circles). Both data sets were sampled at the same compositions, but are slightly shifted in the plot for visibility reasons. The symbols at the edges of this plot are the binary diffusion coefficients of benzene + alcohol (x₂ → 0) and of benzene + acetone (x₃ → 0). Bottom: The binary Fick diffusion coefficient of the subsystems benzene + alcohol and benzene + acetone. Most of the binary experimental data were taken from the literature.^20–27An inspection of Fig. 1(a) provides an unexpected finding: the main element D₁₁ is almost identical for all three mixtures along the examined composition path, i.e. it is independent of the contained type of alcohol. To explain this intriguing behavior of D₁₁, the properties of the pure components are considered first (see