Carbon Nanotubes for the Stabilization of Lipid Nanostructured Particles

Lipid molecules are amphiphilic due to hydrophilic head-group and hydrophobic alkyl chain/s. Lipids are known to self-assemble into remarkable nanostructures in the aqueous medium. In order to enhance their applicability, these nanostructures are further stabilised into nanoparticles using various stabilisers; resultant are the oil-in-water emulsions, which are common in many food and consumer products. Surfactant based stabilisers have been very popular; however, for particular applications the surfactant molecules are not completely beneficial. In this case, the solid materials are employed to obtain surfactant-free emulsions also called Pickering (or Ramsden Pickering) emulsions. Natural and synthetic clays, silica nanoparticles and hydrocolloids have been used for this purpose. Carbon nanotubes (CNTs) have received noteworthy attention due to their unique structural, physical and electrical properties. These properties allow use for a huge range of applications, of which this thesis will outline. In the past, the hydrophobic surface of CNTs have limited their potential in many fields, as well as their tendency to aggregate in most solutions, leading to large amassed particles which prove near-impossible to disperse. The ability to stabilise lipid and CNTs would benefit several areas and applications such as drug delivery and gene therapy. With the techniques in the following report, however, the study has proven that the combination of Dimodan U (DU) and CNTs can form stable nanostructured dispersions, which remain homogeneous for several months. This idea proposes a new way to delivery simple drugs and by tweaking the nanostructure, through alteration of the ratios of CNT to lipid, these systems could be used in targeting different organs

Frequency of <i>KLK3 </i>gene deletions in the general population

Background One of the kallikrein genes ( KLK3) encodes prostate-specific antigen, a key biomarker for prostate cancer. A number of factors, both genetic and non-genetic, determine variation of serum prostate-specific antigen concentrations in the population. We have recently found three KLK3 deletions in individuals with very low prostate-specific antigen concentrations, suggesting a link between abnormally reduced KLK3 expression and deletions of KLK3. Here, we aim to determine the frequency of kallikrein gene 3 deletions in the general population. Methods The frequency of KLK3 deletions in the general population was estimated from the 1958 Birth Cohort sample ( n = 3815) using amplification ratiometry control system. In silico analyses using PennCNV were carried out in the same cohort and in NBS-WTCCC2 in order to provide an independent estimation of the frequency of KLK3 deletions in the general population. Results Amplification ratiometry control system results from the 1958 cohort indicated a frequency of KLK3 deletions of 0.81% (3.98% following a less stringent calling criterion). From in silico analyses, we found that potential deletions harbouring the KLK3 gene occurred at rates of 2.13% (1958 Cohort, n = 2867) and 0.99% (NBS-WTCCC2, n = 2737), respectively. These results are in good agreement with our in vitro experiments. All deletions found were in heterozygosis. Conclusions We conclude that a number of individuals from the general population present KLK3 deletions in heterozygosis. Further studies are required in order to know if interpretation of low serum prostate-specific antigen concentrations in individuals with KLK3 deletions may offer false-negative assurances with consequences for prostate cancer screening, diagnosis and monitoring. </jats:sec

Exploiting horizontal pleiotropy to search for causal pathways within a Mendelian randomization framework

In Mendelian randomization (MR) analysis, variants that exert horizontal pleiotropy are typically treated as a nuisance. However, they could be valuable in identifying alternative pathways to the traits under investigation. Here, we developed MR-TRYX, a framework that exploits horizontal pleiotropy to discover putative risk factors for disease. We begin by detecting outliers in a single exposure-outcome MR analysis, hypothesising they are due to horizontal pleiotropy. We search across hundreds of complete GWAS summary datasets to systematically identify other (candidate) traits that associate with the outliers. We developed a multi-trait pleiotropy model of the heterogeneity in the exposure-outcome analysis due to pathways through candidate traits. Through detailed investigation of several causal relationships, many pleiotropic pathways are uncovered with already established causal effects, validating the approach, but also alternative putative causal pathways. Adjustment for pleiotropic pathways reduces the heterogeneity across the analyses

Amplification ratio control system for copy number variation genotyping

We describe a generic design for ratiometric analysis suitable for determination of copy number variation (CNV) class of a gene. Following two initial sequence-specific PCR priming cycles, both ends of both amplicons (one test and one reference) in a duplex reaction, are all primed by the same universal primer (UP). Following each amplification denaturation step, the UP target and its reverse complement (UP′) in each strand form a hairpin. The bases immediately beyond the 3′-end of the UP and 5′ of UP′ are chosen such as not to base pair in the hairpin (otherwise priming is ablated). This hairpin creates a single constant environment for priming events and chaperones free 3′-ends of amplicon strands. The resultant ‘amplification ratio control system’ (ARCS) permits ratiometric representation of amplicons relative to the original template into PCR plateau phase. These advantages circumvent the need for real-time PCR for quantitation. Choice of different %(G+C) content for the target and reference amplicons allows liquid phase thermal melt discrimination and quantitation of amplicons. The design is generic, simple to set up and economical. Comparisons with real-time PCR and other techniques are made and CNV assays demonstrated for haptoglobin duplicon and ‘chemokine (C-C motif) ligand 3-like 1’ gene

The impact of fatty acids biosynthesis on the risk of cardiovascular diseases in Europeans and East Asians:A Mendelian randomization study

Despite early interest, the evidence linking fatty acids to cardiovascular diseases (CVDs) remains controversial. We used Mendelian randomization to explore the involvement of polyunsaturated (PUFA) and monounsaturated (MUFA) fatty acids biosynthesis in the etiology of several CVD endpoints in up to 1 153 768 European (maximum 123 668 cases) and 212 453 East Asian (maximum 29 319 cases) ancestry individuals. As instruments, we selected single nucleotide polymorphisms mapping to genes with well-known roles in PUFA (i.e. FADS1/2 and ELOVL2) and MUFA (i.e. SCD) biosynthesis. Our findings suggest that higher PUFA biosynthesis rate (proxied by rs174576 near FADS1/2) is related to higher odds of multiple CVDs, particularly ischemic stroke, peripheral artery disease and venous thromboembolism, whereas higher MUFA biosynthesis rate (proxied by rs603424 near SCD) is related to lower odds of coronary artery disease among Europeans. Results were unclear for East Asians as most effect estimates were imprecise. By triangulating multiple approaches (i.e. uni-/multi-variable Mendelian randomization, a phenome-wide scan, genetic colocalization and within-sibling analyses), our results are compatible with higher low-density lipoprotein (LDL) cholesterol (and possibly glucose) being a downstream effect of higher PUFA biosynthesis rate. Our findings indicate that PUFA and MUFA biosynthesis are involved in the etiology of CVDs and suggest LDL cholesterol as a potential mediating trait between PUFA biosynthesis and CVDs risk