TNF-alpha gene polymorphisms can help to predict response to etanercept in psoriatic patients.

BACKGROUND: Genetic factors might have a role for lack of therapeutic response to anti-TNF-alpha agents, as previously suggested in patients with rheumatoid arthritis and inflammatory bowel disease. OBJECTIVES: We evaluated the role of the main TNF-alpha polymorphisms (-238G>A, -308G>A, -857C>T) in predicting the response to etanercept, an anti-TNF-alpha fusion protein. MATERIAL AND METHODS: Genomic DNA was extracted from buccal epithelial cells in a series of 97 psoriatic patients who received etanercept for at least 3 months. Patients were classified as responders, if they achieved a PASI improvement ≥ 75% after 12 weeks of etanercept treatment, and non-responders, if PASI improvement was <75%. Single-nucleotide polymorphisms (SNPs) in TNF-alpha gene (-238G>A, -308G>A, -857C>T) were genotyped by PCR restriction fragment length polymorphism (RFLP) assays. RESULTS: We found that patients heterozygous (GA) for the -238G>A polymorphism were more likely not responsive to therapy compared to the GG genotype. In fact, the GA genotype was found in 5/59 (8.5%) responders and in 14/38 (36.8%) non-responders (P = 0.001). A significant relationship with therapy was also observed for the -308G>A polymorphisms. In fact, the GG, GA and AA genotypes were detected in 48 (81.4%), 9 (15.3%) and 2 (3.4%) of the 59 responders and in 22 (57.9%), 11 (28.9%) and 5 (13.2%) of the 38 non-responder patients (P = 0.03). No association with therapy was observed for the -857C>T polymorphisms. CONCLUSION: Our study supports the role of TNF-alpha polymorphisms in predicting the response to anti-TNF-alpha agents. In particular, we found that the presence of -238G>A and -308G>A polymorphisms is associated with poor response to a 3-month therapy with etanercept. However, our data have yet to be validated in larger cohorts.

An AFM investigation of oligonucleotides anchored on unoxidized crystalline silicon surfaces.

Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (100) silicon surfaces using a cathodic electro grafting technique. The functionalization concentration and efficiency have been evaluated with different techniques. In particular, topographic images, performed with an atomic force microscope, were used to optimize the protocol in order to obtain a surface whose characteristics of uniformity and reproducibility are ideal for a bio-electronic device. Phase lag images of the functionalized surfaces were also performed, and show non-topographic structures that have been interpreted as areas of different molecule self-orientation. Poly-thymine oligonucleotides have been anchored on such a surface to form a nano-biosensing device capable to react selectively with a specific target molecule, a poly-adenine oligonucleotide. AFM images of high density (approximately 3x10(12) mol/cm2) single strand and double strand covered samples show toroidal shaped structures formed by the self-assembly of the oligonucleotides on the silicon surface.

AFM characterization of solid-supported lipid multilayers prepared by spin-coating.

Lipids are the principal components of biologically relevant structures as cellular membranes. They have been the subject of many studies due to their biological relevance and their potential applications. Different techniques, such as Langmuir-Blodgett and vesicle-fusion deposition, are available to deposit ordered lipid films on etched surfaces. Recently, a new technique of lipid film deposition has been proposed in which stacks of a small and well-controlled number of bilayers are prepared on a suitable substrate using a spin-coater. We studied the morphological properties of multi-layers made of cationic and neutral lipids (DOTAP and DOPC) and mixtures of them using dynamic mode atomic force microscopy (AFM). After adapting and optimizing, the spin-coating technique to deposit lipids on a chemically etched Silicon (1,0,0) substrate, a morphological nanometer-scale characterization of the aforementioned samples has been provided. The AFM study showed that an initial layer of ordered vesicles is formed and, afterward, depending on details of the spin-coating preparation protocol and to the dimension of the silicon substrate, vesicle fusion and structural rearrangements of the lipid layers may occur. The present data disclose the possibility to control the lipid's structures by acting on spin-coating parameters with promising perspectives for novel applications of lipid films.