Binder and Interphase Microstructure in a Composite Material Characterized by Scanning Electron Microscopy and NMR Spin Diffusion Experiments

¹H NMR spin diffusion is shown to advantageously complement scanning electron microscopy (SEM) observations for the characterization of polymer structuring in composite materials. It is here demonstrated on a material containing a few percent of polymer binder and a crystalline organic/inorganic mixture as reinforcement. In SEM observations, polymer accumulations are seen. However, the polymer is also expected to fill small porosities and thin layers at the interface of particles to ensure the cohesion and the mechanical properties of the assembly. In most cases, this polymer structuring is invisible considering the resolution and contrast achieved by SEM on such material. It is thus investigated taking advantage of the two‐step decay of nuclear magnetic resonance spin diffusion curves. Average thickness values of 30 and 188 nm are estimated for the interphase and the overall polymer, respectively. Such structural information improves the knowledge of structure/property relationships and provides better understanding of material properties and making processes.     

The effect of delivering the chemokine SDF-1α in a matrix-bound manner on myogenesis

Several chemokines are important in muscle myogenesis and in the recruitment of muscle precursors during muscle regeneration. Among these, the SDF-1α chemokine (CXCL12) is a potent chemoattractant known to be involved in muscle repair. SDF-1α was loaded in polyelectrolyte multilayer films made of poly(l-lysine) and hyaluronan to be delivered locally to myoblast cells in a matrix-bound manner. The adsorbed amounts of SDF-1α were tuned over a large range from 100 ng/cm² to 5 μg/cm², depending on the initial concentration of SDF-1α in solution, its pH, and on the film crosslinking extent. Matrix-bound SDF-1α induced a striking increase in myoblast spreading, which was revealed when it was delivered from weakly crosslinked films. It also significantly enhanced cell migration in a dose-dependent manner, which again depended on its presentation by the biopolymeric film. The low-crosslinked film was the most efficient in boosting cell migration. Furthermore, matrix-bound SDF-1α also increased the expression of myogenic markers but the fusion index decreased in a dose-dependent manner with the adsorbed amount of SDF-1α. At high adsorbed amounts of SDF-1α, a large number of Troponin T-positive cells had only one nucleus. Overall, this work reveals the importance of the presentation mode of SDF-1α to emphasize its effect on myogenic processes. These films may be further used to provide insight into the role of SDF-1α presented by a biomaterial in physiological or pathological processes.     

Post-voiding residual volume in 154 primiparae 3 days after vaginal delivery under epidural anesthesia

OBJECTIVES: To use 3-dimensional ultrasonography (3D-US) to determine the frequency of post-voiding residual volume (PVRV) > or =100 mL in primiparae 3 days after receiving epidural anesthesia for vaginal delivery. Potential relationships between day-3 PVRV > or =100 mL and obstetrical-pediatric parameters, especially those possibly implicated in post-obstetrical bladder dysfunction, were examined. STUDY DESIGN: We recruited 154 primiparae who vaginally delivered term singletons following uncomplicated pregnancies in the maternity unit of a French teaching hospital. All women had been systematically catheterized 2-h postpartum to measure precisely the volume of urine retained. On the morning of discharge (day 3), when the patient felt the urge to urinate, her 3D-US pre-voiding bladder volume was determined with BladderScan (BVI-3000), then her spontaneously voided urine was collected to accurately quantify its volume and 3D-US was repeated immediately to evaluate the PVRV. PVRV > or =100 mL on day 3 was considered pathological. RESULT: Among these 154 women, 88 (57%) felt the need to urinate and 97 (63%) had a retained volume > or =500 mL at 2-h postpartum. On day-3 postpartum, the median [range] volumes for the entire cohort were: 426.7 [158-999.7] mL 3D-US-measured pre-voiding, 350 [15-1000] mL collected by spontaneous urination, 82.2 [5.3-433.3] mL 3D-US-determined post-voiding; PVRV exceeded 100 mL for 55 (36%). According to our univariate analysis, no factor considered was able to predict PVRV > or =100 mL on day 3. CONCLUSION: Our observations confirmed the existence of PVRV > or =100 mL on day 3 in more than one-third of these primiparae who delivered vaginally under epidural anesthesia. No obstetrical-pediatric factor could be implicated in this bladder dysfunction. Therefore, we recommend frequent and systematic non-invasive 3D-US monitoring of all postpartum patients at least until day 3 to avoid excessive urine retention.     

Gemcitabine-induced peripheral vascular disease and prolonged response in a patient with metastatic pancreatic adenocarcinoma: A case report

BACKGROUND Gemcitabine is an antimetabolite used in the treatment of pancreatic cancer. One of the side effects of gemcitabine is vascular toxicity. Here, we report the case of a patient treated with gemcitabine who had peripheral vascular disease concomitant with a prolonged antitumor response.CASE SUMMARY A 75-year-old man was diagnosed with locally recurrent pancreatic cancer. Partial response was achieved after 9 mo of gemcitabine. At the same time, the patient reported peripheral vascular d...