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Biomedical subjects

M Olek

Publications and source records attributed to M Olek.

8 recordsLinked to original sources
PubMed2006

Highly ordered MWNT-based matrixes: topography at the nanoscale conceived for tissue engineering.

A method based on the conventional lithographic technique combined with the layer-by-layer (LBL) assembly process is applied to the construction of free-standing micro- and nanostructured matrixes. The method enables controlled shaping and considerable chemical and mechanical stability of the self-assembled monolayers, allowing for high reproducibility in manufacturing. The matrixes are characterized by controlled geometry, surface topography, and chemical composition. The complete architecture is made up of successive layers of intercrossed carbon nanotubes that self-assemble into orderly structures. In particular, the present method aims to create architectures and topographies that mimic those occurring naturally (native tissue structures). In addition, nanoindentation and nanoscratch techniques were used to evaluate the mechanical properties of the carbon nanotube-based matrixes.

Extracellular Matrix↗
PubMed2005

Nanomechanical properties of silica-coated multiwall carbon nanotubes-poly(methyl methacrylate) composites.

The mechanical properties of polymer composites, reinforced with silica-coated multiwall carbon nanotubes (MWNTs), have been studied using the nanoindentation technique. The hardness and the Young's modulus have been found to increase strongly with the increasing content of these nanotubes in the polymer matrix. Similar experiments conducted on thin films containing MWNTs, but without a silica shell, revealed that the presence of these nanotubes does not affect the nanomechanical properties of the composites. While carbon nanotubes (CNTs) have a very high tensile strength due to the nanotube stiffness, composites fabricated with CNTs may exhibit inferior toughness. The silica shell on the surface of a nanotube enhances its stiffness and rigidity. Our composites, at 4 wt % of the silica-coated MWNTs, display a maximum hardness of 120 +/- 20 MPa, and a Young's modulus of 9 +/- 1 GPa. These are respectively 2 and 3 times higher than those for the polymeric matrix. Here, we describe a method for the silica coating of MWNTs. This is a simple and efficient technique, adaptable to large-scale production, and might lead to new advanced polymer based materials, with very high axial and bending strength.

Journal Article↗
PubMed2005

A randomized blinded trial of combination therapy with cyclophosphamide in patients-with active multiple sclerosis on interferon beta.

OBJECTIVE: To evaluate the efficacy and safety of combination therapy with pulse cyclophosphamide given with methylprednisolone (MP) and interferon beta (IFNbeta)-Ia in multiple sclerosis (MS) patients with active disease during IFNbeta monotherapy. METHODS: This was a randomized, single-blind, parallel-group, multicenter trial in MS patients with a history of active disease during IFNbeta treatment. Patients were randomized to either cyclophosphamide 800 mg/m2 plus methylprednisolone 1 g IV (CY/MP) or methylprednisolone once a month for six months and then followed for an additional 18 months. All patients received three days of methylprednisolone 1 g IV at screening and 30 mcg IFNbeta-Ia IM weekly for the entire 24 months. The primary endpoint was change from baseline in the mean number of gadolinium-enhancing (Gd+) lesions. Secondary clinical endpoints included time to treatment failure. RESULTS: Fifty-nine patients were randomized to treatment: 30 to CY/MP and 29 to MP Change from baseline in the number of Gd+ lesions was significantly different between treatment groups at three (P =0.01), six (P =0.04) and 12 months (P =0.02), with fewer lesions in the CY/MP group. The cumulative rate of treatment failure was significantly lower in the CY/MP group compared with the MP group (rate ratio =0.30; 95% confidence interval, 0.12-0.75; P =0.011). CY/MP treatment was well tolerated. CONCLUSION: Combination therapy with CY/MP and IFNbeta-Ia decreased the number of Gd+ lesions and slowed clinical activity in patients with previously active disease on IFNbeta alone.

Adjuvants, Immunologic↗