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Purpose: Several studies have described molecular differences between microsatellite stable hereditary nonpolyposis colorectal cancer (MSS-HNPCC) and microsatellite unstable Lynch syndrome tumors (MSI-HNPCC). These differences highlight the possibility that other instability forms could explain cancer susceptibility in this group of families.The base excision repair (BER) pathway is the major DNA repair pathway for oxidative DNA damage. A defect in this pathway can result in DNA transversion mutations and a subsequent increased cancer risk. Mutations in MUTYH have been associated with increased colorectal cancer (CRC) risk while no association has been described for OGG1 or NUDT1.Experimental Design: We performed mutational screening of the three genes involved in defense against oxidative DNA damage in a set of 42 MSS-HNPCC families.Results: Eight rare variants and 5 frequent variants were found in MSS-HNPCC patients. All variants were previously described by other authors except variant c.285C>T in OGG1. Segregation studies were done and in silico programs were used to estimate the level of amino acid conservation, protein damage prediction, and possible splicing alterations. Variants OGG1 c.137G>A; MUTYH c.1187G>A were detected in Amsterdam I families and cosegregate with cancer. Analysis of OGG1 c.137G>A transcripts showed an inactivation of the splicing donor of exon 1.Conclusions: Two rare variants (OGG1 c.137G>A; MUTYH c.1187G>A) and one common polymorphism (NUDT1 c.426C>T) were associated with CRC risk. We show that the BER pathway can play a significant role in a number of MSS-HNPCC colorectal cancers. More studies could be of interest in order to gain further understanding of yet unexplained CRC susceptibility cases. Clin Cancer Res; 17(7); 1701–12. ©2011 AACR.

Objectives: To quantify the workload and cost overload that the COVID-19 pandemic has meant for a Clinical Microbiology laboratory in a real-life scenario. Methods: We compared the number of samples received, their distribution, the human resources, and the budget of a Microbiology laboratory in the COVID pandemic (March–December 2020) with the same months of the previous year. Results: the total number of samples processed in the Clinical Microbiology laboratory in March to December 2020 increased 96.70% with respect to 2019 (from 246,060 to 483,993 samples), reflecting an increment of 127.50% when expressed as samples/1000 admissions (from 6057 to 13,780). The increase in workload was mainly at the expense of the virology (+2058%) and serology (+86%) areas. Despite additional personnel hiring, the samples processed per technician increased 12.5%. The extra cost attributed to Microbiology amounts to 6,616,511 euros (114.8%). Conclusions: This is the first study to provide quantitative figures about workload and cost increase caused by the COVID-19 in a Microbiology laboratory.

Purpose: Several studies have described molecular differences between microsatellite stable hereditary nonpolyposis colorectal cancer (MSS-HNPCC) and microsatellite unstable Lynch syndrome tumors (MSI-HNPCC). These differences highlight the possibility that other instability forms could explain cancer susceptibility in this group of families. The base excision repair (BER) pathway is the major DNA repair pathway for oxidative DNA damage. A defect in this pathway can result in DNA transversion mutations and a subsequent increased cancer risk. Mutations in MUTYH have been associated with increased colorectal cancer (CRC) risk while no association has been described for OGG1 or NUDT1. Experimental Design: We performed mutational screening of the three genes involved in defense against oxidative DNA damage in a set of 42 MSS-HNPCC families. Results: Eight rare variants and 5 frequent variants were found in MSS-HNPCC patients. All variants were previously described by other authors except variant c.285C>T in OGG1. Segregation studies were done and in silico programs were used to estimate the level of amino acid conservation, protein damage prediction, and possible splicing alterations. Variants OGG1 c.137G>A; MUTYH c.1187G>A were detected in Amsterdam I families and cosegregate with cancer. Analysis of OGG1 c.137G>A transcripts showed an inactivation of the splicing donor of exon 1. Conclusions: Two rare variants (OGG1 c.137G>A; MUTYH c.1187G>A) and one common polymorphism (NUDT1 c.426C>T) were associated with CRC risk. We show that the BER pathway can play a significant role in a number of MSS-HNPCC colorectal cancers. More studies could be of interest in order to gain further understanding of yet unexplained CRC susceptibility cases. Clin Cancer Res; 17(7); 1701–12. ©2011 AACR.

Cholesterol-based lipophilic oligonucleotides incorporated into lipid membranes were studied using solid-state NMR, differential scanning calorimetry, and fluorescence methods. Lipophilic oligonucleotides can be used to build nanotechnological structures on membrane surfaces, taking advantage of the specific Watson-Crick base pairing. We used a cholesteryl-TEG anchor first described by Pfeiffer and Hook (J. Am. Chem. Soc. 2004, 126, 10224-10225). The cholesterol-based anchor molecules were found to incorporate well into lipid membranes without disturbing the bilayer structure and dynamics. In contrast to cholesterol, which is known to induce significant condensation of the membrane lipids, the cholesteryl-TEG anchor does not display this property. When the cholesteryl-TEG moiety was covalently bound to an oligonucleotide, the resulting lipophilic DNA molecules inserted spontaneously into lipid membranes without altering their structure. The duplex formed by two complementary cholesteryl-TEG oligonucleotides had increased thermodynamic stability compared to the same oligonucleotides without the anchor, both in solution and incorporated into lipid membranes. Since the cholesteryl-TEG anchor lacks the characteristic properties of cholesterol, oligonucleotides modified with this anchor are equally distributed between liquid-disordered and liquid-ordered domains in "raft" forming membranes. As an example of an application of these lipophilic oligonucleotides, cholesteryl-TEG-DNA was incorporated into supported lipid bilayers formed on polyelectrolyte-coated silica microparticles. The modified oligonucleotides were stably inserted into the lipid membrane and retained their recognition properties, therefore enabling further functionalization of the particles.

We describe the formation of lipid microtubes from a novel cholesterol-modified nucleoside in binary mixture with phospholipids. Stable cylindrical structures with an outer diameter of 2-3 microm and a length of 20-40 microm were formed. By varying the preparation conditions, thinner tubules with nanometre-scale diameters could also be obtained.

The mechanism of formation of supported lipid layers from phosphatidylcholine and phosphatidylserine vesicles in solution on polyelectrolyte multilayers was studied by a variety of experimental techniques. The interaction of zwitterionic and acidic lipid vesicles, as well as their mixtures, with polyelectrolyte supports was followed in real time by micro-gravimetry. The fabricated lipid–polyelectrolyte composite structures on top of multilayer coated colloidal particles were characterized by flow cytometry and imaging techniques. Lipid diffusion over the macroscopic scale was quantified by fluorescence recovery after photobleaching, and the diffusion was related to layer connectivity. The phospholipid–polyelectrolyte binding mechanism was investigated by infrared spectroscopy. A strong interaction of polyelectrolyte primary amino groups with phosphate and carboxyl groups of the phospholipids, leading to dehydration, was observed. Long-range electrostatic attraction was proven to be essential for vesicle spreading and rupture. Fusion of lipid patches into a homogeneous bilayer required lateral mobility of the lipids on the polyelectrolyte support. The binding of amino groups to the phosphate group of the zwitterionic lipids was too weak to induce vesicle spreading, but sufficient for strong adsorption. Only the mixture of phosphatidylcholine and phosphatidylserine resulted in the spontaneous formation of bilayers on polyelectrolyte multilayers. The adsorption of phospholipids onto multilayers displaying quarternary ammonium polymers produced a novel 3D lipid polyelectrolyte structure on colloidal particles.