Measurement of von Willebrand factor binding to a recombinant fragment of glycoprotein Ibalpha in an enzyme-linked immunosorbent assay-based method: performances in patients with type 2B von Willebrand disease

Type 2B von Willebrand disease (VWD) is characterised by an increased affinity of von Willebrand factor (VWF) for its platelet receptor glycoprotein Ib (GPIb). This feature is usually studied in vitro by a ristocetin-dependent VWF platelet-binding assay, which has some limitations as it requires [e.g. (radio)-labelled anti-VWF antibodies and normal formaldehyde-fixed platelets]. We, here, extended the applicability of an enzyme-linked immunosorbent assay-based method previously described for the measurement of ristocetin co-factor activity that used a recombinant fragment of GPIb (rfGPIb alpha) and horseradish peroxidase-labelled rabbit anti-human VWF antibodies for measuring the captured ristocetin-VWF complexes on the rfGPIb alpha. Thirty-one type 2B VWD patients from 15 families with eight different known mutations were studied. VWF in plasma from 28 of these patients bound better than normal VWF at 0.2 mg/ml ristocetin, with the ratio, optical density (OD) patient/OD normal pool plasma, higher than 1.8. For two of the three other patients with no enhanced response of plasma VWF, the platelet lysate VWF showed an enhanced binding capacity; for the last patient, the results in other members of the family are unequivocal. We conclude that, this new method for measurement of plasma or platelet VWF-binding capacity offers great advantages for correct type 2B VWD diagnosis.     

Tailoring the surface properties of Ti6Al4V by controlled chemical oxidation

Many efforts have been made to promote cell activity at the surface of implants, mainly by modifying their topography and physicochemical properties. Here we demonstrate the feasibility of creating Ti6Al4V surfaces having both a microtexture and a nanotexture, and show that their properties can be tailored by controlling the length of exposure to a mixture of H2SO4 and H2O2. Scanning electron microscopy (SEM), combined with energy-dispersive X-ray spectroscopy (EDX), indicated that beta-phase grains, which surround larger alpha-phase grains, are etched more rapidly, resulting in a surface composed of microscale cavities with alpha-grain boundaries. Furthermore, high-resolution SEM and atomic force microscopy (AFM) revealed the presence on the surfaces of both alpha- and beta-phase grains of a network of nanopits with mean diameters ranging between 13 and 21 nm. The grain surface roughness increases from about 4 nm on untreated samples to about 12 nm after 4h of treatment. AFM analysis showed that the depth of microscale cavities can be varied in the 10-180 nm range by controlling the extent of chemical etching. Fourier transform infrared spectroscopy (FT-IR), combined with ellipsometry, established that the etching generated an oxide layer with a thickness in the range 15-45 nm. The resulting new surfaces selectively promote the growth of osteoblasts while inhibiting that of fibroblasts, making them promising tools for regulating the activities of cells in biological environments.     

Diversity of tailed phages in Baltic Sea sediment: large number of siphoviruses with extremely long tails

We present the first attempt at quantitative analysis of morphological diversity of tailed viruses obtained from marine sediments without ultracentrifugation or enrichment on specific host strains. Sandy mud samples were collected in the Gulf of Gdańsk in the spring, autumn and winter. VLPs were analyzed by transmission electron microscopy. The distribution of three groups of tailed phages was similar in all seasons (Siphoviridae: 52% on average; Myoviridae: 42%; Podoviridae: 6%). 19% of siphoviruses had prolate heads. Interestingly, 11% of siphoviral particles had tails longer than 300 nm, and 6% longer than 600 nm.     

US preschoolers’ trust of and learning from media characters

The current study examined the relations between children’s perceptions of character social realism, identification with characters, trust of characters as knowledgeable informants, and learning from media characters. Thirty-six 3½- to 6-year-old children watched a short clip of an animated educational television program about a preschool-aged boy who enjoys learning about science. Participants provided ratings of the character’s social realism, their identification with the character, and their trust in the character as a knowledgeable informant. Participants were asked to solve problems based on information in the video clip. Findings revealed character trust was the strongest indicator of learning from the character. Results are discussed in the context of the different factors that influence learning from curriculum-based media for young children.     

Polyelectrolyte multilayers functionalized by a synthetic analogue of an anti-inflammatory peptide, alpha-MSH, for coating a tracheal prosthesis

Polyelectrolyte multilayer films made of poly (L-lysine) (PLL) and poly (L-glutamic acid) (PGA) have been functionalized by covalent binding of a synthetic analogue of the anti-inflammatory peptide, alpha-melanocyte-stimulating hormone (alpha-MSH) to PGA to create biologically active coatings for tracheal prostheses. The morphology and in vivo stability of the films were investigated by atomic force microscopy and confocal laser scanning microscopy, respectively. For the in vivo evaluation, 87 rats were implanted and examined for a period superior to 3 months. Histological analysis, performed 1 month after implantation, showed a fibroblast colonization of the periprosthetic side and a respiratory epithelium type on the endoluminal side of the implant for all the polyelectrolyte coatings tested. However, for prostheses modified by PGA ending multilayer films, a more regular and less obstructive cell layer was observed on the endoluminal side compared to those modified by PLL ending films. Systemic anti-inflammatory IL-10 production was only detected in rats implanted with prostheses functionalized by alpha-MSH, demonstrating, in vivo, the anti-inflammatory activity of the embedded peptide into multilayer architectures.     

Effect of open label pulse cyclophosphamide therapy on MRI measures of disease activity in five patients with refractory relapsing-remitting multiple sclerosis.

OBJECTIVE: To evaluate the response to cyclophosphamide (CTX) of five patients who failed an average three treatments with multiple other therapeutic agents, using serial monthly MRI measures. METHODS: Five patients with relapsing-remitting multiple sclerosis (MS) and documented MRI disease activity were started on monthly pulse intravenous CTX at a dose of 1 g/m2. CTX was administered without an induction phase according to the protocol similar to the treatment of lupus nephritis. The five patients were followed with monthly MRI and clinical evaluation for a mean of 28 months. RESULTS: All the patients showed a rapid reduction in the contrast-enhancing lesion frequency and in three patients there was a decrease in the T2 lesion load within the first 5 months after starting CTX treatment. The administration of CTX during overnight hospitalization was safe and well tolerated. CONCLUSIONS: These findings suggest that aggressive immunosuppressive therapy may be useful in some rapidly deteriorating refractory patients and further controlled study should be considered in order to full evaluate this type of treatment as a potential therapy in MS.