Effect of Clinical Parameters on Risk of Death from Cancer after Radical Prostatectomy in Men with Localized and Locally Advanced Prostate Cancer

Background: The study aimed to assess predictors and to identify patients at increased risk of prostate-cancer-specific mortality (CSM) after radical prostatectomy (RP). Methods: A total of 2421 men with localized and locally advanced PCa who underwent RP in 2001–2017 were included in the study. CSM predictors were assessed using multivariate competing risk analysis. Death from other causes was considered a competing event. Cumulative CSM and other-cause mortality (OCM) were calculated in various combinations of predictors. Results: During the median 8 years (interquartile range 4.4–11.7) follow-up, 56 (2.3%) of registered deaths were due to PCa. Cumulative 10 years CSM and OCM was 3.6% (95% CI 2.7–4.7) and 15.9% (95% CI 14.2–17.9), respectively. The strongest predictors of CSM were Grade Group 5 (GG5) (hazard ratio (HR) 19.9, p p = 0.001), stage pT3b-4 (HR 3.1, p = 0.009), and age (HR 1.1, p = 0.0007). In groups created regarding age, stage, and GG, cumulative 10 years CSM ranged from 0.4–84.9%, whereas OCM varied from 0–43.2%. Conclusions: CSM after RP is related to GGs, pathological stage, age, and combinations of these factors, whereas other-cause mortality is only associated with age. Created CSM and OCM plots can help clinicians identify patients with the most aggressive PCa who could benefit from more intensive or novel multimodal treatment strategies

Modification of Tethered Bilayers by Phospholipid Exchange with Vesicles

Phosphatidylcholine and cholesterol exchange between vesicles and planar tethered bilayer lipid membranes (tBLMs) was demonstrated from electrochemical impedance spectroscopy (EIS), fluorescence microscopy (FM), and neutron reflectometry (NR) data. Cholesterol is incorporated into the tBLMs, as determined by the functional reconstitution of the pore forming toxin α-hemolysin (EIS data), attaining cholesterol concentrations nearly equal to that in the donor vesicles. Using fluorescently labeled lipids and cholesterol, FM indicates that the vesicle–tBLM exchange is homogeneous for the lipids but not for cholesterol. NR data with perdeuterated lipids indicates lipid exchange asymmetry with two lipids exchanged in the outer leaflet for every lipid in the inner leaflet. NR and EIS data further show different exchange rates for cholesterol (<i>t</i>_1/2 < 60 min) and phosphatidylcholine (<i>t</i>_1/2 > 4 h). This work lays the foundation for the preparation of robust, lower defect, more biologically relevant tBLMs by essentially combining the two methods of tBLM formation–rapid solvent exchange and vesicle fusion

Structure and Function of the Membrane Anchoring Self-Assembled Monolayers

Structure of the self-assembled monolayers (SAMs) used to anchor phospholipid bilayers to surfaces affects the functional properties of the tethered bilayer membranes (tBLMs). SAMs of the same surface composition differing in the lateral distribution of the anchor molecule give rise to tBLMs of profoundly different defectiveness with residual conductance spanning 3 orders of magnitude. SAMs composed of anchors containing saturated alkyl chains, upon exposure to water (72 h), reconstruct to tightly packed clusters as deduced from reflection absorption infrared spectroscopy data and directly visualized by atomic force microscopy. The rearrangement into clusters results in an inability to establish highly insulating tBLMs on the same anchor layer. Unexpectedly, we also found that nanometer scale smooth gold film surfaces, populated predominantly with (111) facets, exhibit poor performance from the standpoint of the defectiveness of the anchored phospholipid bilayers, while corrugated (110) dominant surfaces produced SAMs with superior tethering quality. Although the detailed mechanism of cluster formation remains to be clarified, it appears that smooth surfaces favor lateral translocation of the molecular anchors, resulting in changes in functional properties of the SAMs. This work unequivocally establishes that conditions that favor cluster formation of the anchoring molecules in tBLM formation must be identified and avoided for the functional use of tBLMs in biomedical and diagnostic applications

Structure and properties of tethered bilayer lipid membranes with unsaturated anchor molecules.

The self-assembled monolayers (SAMs) of new lipidic anchor molecule HC18 [Z-20-(Z-octadec-9-enyloxy)-3,6,9,12,15,18,22-heptaoxatetracont-31-ene-1-thiol] and mixed HC18/β-mercaptoethanol (βME) SAMs were studied by spectroscopic ellipsometry, contact angle measurements, reflection-absorption infrared spectroscopy, and electrochemical impedance spectroscopy (EIS) and were evaluated in tethered bilayer lipid membranes (tBLMs). Our data indicate that HC18, containing a double bond in the alkyl segments, forms highly disordered SAMs up to anchor/βME molar fraction ratios of 80/20 and result in tBLMs that exhibit higher lipid diffusion coefficients relative to those of previous anchor compounds with saturated alkyl chains, as determined by fluorescence correlation spectroscopy. EIS data shows the HC18 tBLMs, completed by rapid solvent exchange or vesicle fusion, form more easily than with saturated lipidic anchors, exhibit excellent electrical insulating properties indicating low defect densities, and readily incorporate the pore-forming toxin α-hemolysin. Neutron reflectivity measurements on HC18 tBLMs confirm the formation of complete tBLMs, even at low tether compositions and high ionic lipid compositions. Our data indicate that HC18 results in tBLMs with improved physical properties for the incorporation of integral membrane proteins (IMPs) and that 80% HC18 tBLMs appear to be optimal for practical applications such as biosensors where high electrical insulation and IMP/peptide reconstitution are imperative.</p

Structure and Properties of Tethered Bilayer Lipid Membranes with Unsaturated Anchor Molecules

The self-assembled monolayers (SAMs) of new lipidic anchor molecule HC18 [<i>Z</i>-20-(<i>Z</i>-octadec-9-enyloxy)-3,6,9,12,15,18,22-heptaoxatetracont-31-ene-1-thiol] and mixed HC18/β-mercaptoethanol (βME) SAMs were studied by spectroscopic ellipsometry, contact angle measurements, reflection–absorption infrared spectroscopy, and electrochemical impedance spectroscopy (EIS) and were evaluated in tethered bilayer lipid membranes (tBLMs). Our data indicate that HC18, containing a double bond in the alkyl segments, forms highly disordered SAMs up to anchor/βME molar fraction ratios of 80/20 and result in tBLMs that exhibit higher lipid diffusion coefficients relative to those of previous anchor compounds with saturated alkyl chains, as determined by fluorescence correlation spectroscopy. EIS data shows the HC18 tBLMs, completed by rapid solvent exchange or vesicle fusion, form more easily than with saturated lipidic anchors, exhibit excellent electrical insulating properties indicating low defect densities, and readily incorporate the pore-forming toxin α-hemolysin. Neutron reflectivity measurements on HC18 tBLMs confirm the formation of complete tBLMs, even at low tether compositions and high ionic lipid compositions. Our data indicate that HC18 results in tBLMs with improved physical properties for the incorporation of integral membrane proteins (IMPs) and that 80% HC18 tBLMs appear to be optimal for practical applications such as biosensors where high electrical insulation and IMP/peptide reconstitution are imperative