Characterization of Diclofenac Liposomes Formulated with Palm Oil Fractions

Purpose: To characterize diclofenac sodium (DS) liposomes prepared using palm oil fractions.Methods: Reverse-phase evaporation method was used to prepare liposomes containing 10, 20, 30 , 40 or 50% palm oil fractions. The effect of palm oil content on liposome formation, surface morphology, shape, size and zeta potential of the liposomes were studied using scanning electron microscopy (SEM) transmission electron microscopy (TEM) and particle analyzer. Drug loading, entrapment efficiency and in vitro drug release were measured in phosphate-buffered saline (PBS, pH 7.4) by UV spectrophotometry.Results: TEM and SEM images showed formation of liposomes for all formulations, However, increase in the proportion of palm oil in the formulations significantly reduced particle size and increased zeta potential. The effect on drug loading and drug release varied with palm oil fraction. The best release pattern with appropriate entrapment efficiency and stability was obtained with liposomes containing 33 % palm oil fraction. Introduction of 46 and 56 % of palm oil fractions yielded zeta potential of -42.8 and - 50.7 mV, respectively, compared with -31.2 mV for the formulation without palm oil.Conclusion: The results demonstrate the potentials of palm oil fractions in the preparation of suitable DS liposomes with good bioavailability.Keywords: Liposome, Drug delivery, Palm oil, Diclofenac

The experience of visual art for people living with mild-to-moderate vision loss

Background: Visual art can enhance wellbeing and quality-of-life; however, the experience of visual art for people with mild-to-moderate vision loss has not been examined. Methods: Eight participants (6 females, 2 males; Mean age = 81 years, SD = 7.9, range 70–91 years; 4 with mild vision loss and 4 with moderate vision loss based on binocular visual acuity) completed a mixed-methods study comprising: a semi-structured interview on visual art experience; an eye examination; and questionnaires about visual functioning and quality-of-life. Results: Various themes were identified: visual perception of art (e.g. altered colours, visual distortions, etc.), viewing conditions, elements of art, personal preference, deriving meaning, appreciation of art, impact of impaired visual perception, and social aspects of art. Conclusions: The overall experience of art is influenced by how an individual sees, perceives, and makes meaning from art. Even mild vision loss can impair this experience and impact emotional and social wellbeing.</p

Gene Expression Levels Are a Target of Recent Natural Selection in the Human Genome

Changes in gene expression may represent an important mode of human adaptation. However, to date, there are relatively few known examples in which selection has been shown to act directly on levels or patterns of gene expression. In order to test whether single nucleotide polymorphisms (SNPs) that affect gene expression in cis are frequently targets of positive natural selection in humans, we analyzed genome-wide SNP and expression data from cell lines associated with the International HapMap Project. Using a haplotype-based test for selection that was designed to detect incomplete selective sweeps, we found that SNPs showing signals of selection are more likely than random SNPs to be associated with gene expression levels in cis. This signal is significant in the Yoruba (which is the population that shows the strongest signals of selection overall) and shows a trend in the same direction in the other HapMap populations. Our results argue that selection on gene expression levels is an important type of human adaptation. Finally, our work provides an analytical framework for tackling a more general problem that will become increasingly important: namely, testing whether selection signals overlap significantly with SNPs that are associated with phenotypes of interest

Genome-wide scans provide evidence for positive selection of genes implicated in Lassa fever

Rapidly evolving viruses and other pathogens can have an immense impact on human evolution as natural selection acts to increase the prevalence of genetic variants providing resistance to disease. With the emergence of large datasets of human genetic variation, we can search for signatures of natural selection in the human genome driven by such disease-causing microorganisms. Based on this approach, we have previously hypothesized that Lassa virus (LASV) may have been a driver of natural selection in West African populations where Lassa haemorrhagic fever is endemic. In this study, we provide further evidence for this notion. By applying tests for selection to genome-wide data from the International Haplotype Map Consortium and the 1000 Genomes Consortium, we demonstrate evidence for positive selection in LARGE and interleukin 21 (IL21), two genes implicated in LASV infectivity and immunity. We further localized the signals of selection, using the recently developed composite of multiple signals method, to introns and putative regulatory regions of those genes. Our results suggest that natural selection may have targeted variants giving rise to alternative splicing or differential gene expression of LARGE and IL21. Overall, our study supports the hypothesis that selective pressures imposed by LASV may have led to the emergence of particular alleles conferring resistance to Lassa fever, and opens up new avenues of research pursuit

Population Genetic Study of the Brain-Derived Neurotrophic Factor (BDNF) Gene

Genetic variants in the brain-derived neurotrophic factor (BDNF) gene, predominantly the functional Val66Met polymorphism, have been associated with risk of bipolar disorder and other psychiatric disorders. However, not all studies support these findings, and overall the evidence for the association of BDNF with disease risk is weak. As differences in population genetic structure between patient samples could cause discrepant or spurious association results, we investigated this possibility by carrying out population genetic analyses of the BDNF genomic region. Substantial variation was detected in BDNF coding region single-nucleotide polymorphism (SNP) allele and haplotype frequencies between 58 global populations, with the derived Met allele of Val66Met ranging in frequency from 0 to 72% across populations. FST analyses to assess diversity in the HapMap populations determined that the Val66Met FST value was at the 99.8th percentile among all SNPs in the genome. As the BDNF population genetic differences may be due to local selection, we performed the long-range haplotype test for selection using 68 SNPs spanning the BDNF genomic region in 12 European-derived pedigrees. Evidence for positive selection was found for a high-frequency Val-carrying haplotype, with a relative extended haplotype homozygosity value above the 99th percentile compared with HapMap data $(P=4.6 \times 10^{−4})$. In conclusion, we observed considerable BDNF allele and haplotype diversity among global populations and evidence for positive selection at the BDNF locus. These phenomena can have a profound impact on the detection of disease susceptibility genes and must be considered in gene association studies of BDNF.Organismic and Evolutionary BiologyOther Research Uni

Rapid Objective Testing of Visual Function Matched to the ETDRS Grid and Its Diagnostic Power in Age-Related Macular Degeneration

Purpose: To study the power of an 80-second multifocal pupillographic objective perimetry (mfPOP) test tailored to the ETDRS grid to diagnose age-related macular degeneration (AMD) by Age-Related Eye Disease Study (AREDS) severity grade. Design: Evaluation of a diagnostic technology. Methods: We compared diagnostic power of acuity, ETDRS grid retinal thickness data, new 80-second M18 mfPOP test, and two wider-field 6-minute mfPOP tests (Macular-P131, Widefield-P129). The M18 stimuli match the size and shape of bifurcated ETDRS grid regions, allowing easy structure–function comparisons. M18, P129, and P131 stimuli test both eyes concurrently. We recruited 34 patients with early-stage AMD with a mean ± standard deviation (SD) age of 72.6 ± 7.06 years. The M18 and P129 plus P131 stimuli had 26 and 51 control participants, respectively with mean ± SD ages of 73.1 ± 8.17 years and 72.1 ± 5.83 years, respectively. Multifocal pupillographic objective perimetry testing used the Food and Drug Administration-cleared Objective FIELD Analyzer (OFA; Konan Medical USA). Main Outcome Measures: Percentage area under the receiver operator characteristic curve (AUC) and Hedge's g effect size. Results: Acuity and OCT ETDRS grid thickness and volume produced reasonable diagnostic power (percentage AUC) for AREDS grade 4 eyes at 83.9 ± 9.98% and 90.2 ± 6.32% (mean ± standard error), respectively, but not for eyes with less severe disease. By contrast, M18 stimuli produced percentage AUCs from 72.8 ± 6.65% (AREDS grade 2) to 92.9 ± 3.93% (AREDS grade 4), and 82.9 ± 3.71% for all eyes. Hedge's g effect sizes ranged from 0.84 to 2.32 (large to huge). Percentage AUC for P131 stimuli performed similarly and for P129 performed somewhat less well. Conclusions: The rapid and objective M18 test provided diagnostic power comparable with that of wider-field 6-minute mfPOP tests. Unlike acuity or OCT ETDRS grid data, OFA tests produced reasonable diagnostic power in AREDS grade 1 to 3 eyes.</p

SARS-CoV-2 Spike protein variant D614G increases infectivity and retains sensitivity to antibodies that target the receptor binding domain [preprint]

Virus genome sequence variants that appear over the course of an outbreak can be exploited to map the trajectory of the virus from one susceptible host to another. While such variants are usually of no functional significance, in some cases they may allow the virus to transmit faster, change disease severity, or confer resistance to antiviral therapies. Since the discovery of SARS-CoV-2 as the cause of COVID-19, the virus has spread around the globe, and thousands of SARS-CoV-2 genomes have been sequenced. The rate of sequence variation among SARS-CoV-2 isolates is modest for an RNA virus but the enormous number of human-to-human transmission events has provided abundant opportunity for selection of sequence variants. Among these, the SARS-CoV-2 Spike protein variant, D614G, was not present in the presumptive common ancestor of this zoonotic virus, but was first detected in late January in Germany and China. The D614G variant steadily increased in frequency and now constitutes \u3e97% of isolates world-wide, raising the question whether D614G confers a replication advantage to SARS-CoV-2. Structural models predict that D614G would disrupt contacts between the S1 and S2 domains of the Spike protein and cause significant shifts in conformation. Using single-cycle vectors we showed that D614G is three to nine-fold more infectious than the ancestral form on human lung and colon cell lines, as well as on other human cell lines rendered permissive by ectopic expression of human ACE2 and TMPRSS2, or by ACE2 orthologues from pangolin, pig, dog, or cat. Nonetheless, monoclonal antibodies targeting the receptor binding domain of the SARS-CoV-2 Spike protein retain full neutralization potency. These results suggest that D614G was selected for increased human-to-human transmission, that it contributed to the rapidity of SARS-CoV-2 spread around the world, and that it does not confer resistance to antiviral therapies targeting the receptor binding domain

Combining genomics and epidemiology to track mumps virus transmission in the United States.

Unusually large outbreaks of mumps across the United States in 2016 and 2017 raised questions about the extent of mumps circulation and the relationship between these and prior outbreaks. We paired epidemiological data from public health investigations with analysis of mumps virus whole genome sequences from 201 infected individuals, focusing on Massachusetts university communities. Our analysis suggests continuous, undetected circulation of mumps locally and nationally, including multiple independent introductions into Massachusetts and into individual communities. Despite the presence of these multiple mumps virus lineages, the genomic data show that one lineage has dominated in the US since at least 2006. Widespread transmission was surprising given high vaccination rates, but we found no genetic evidence that variants arising during this outbreak contributed to vaccine escape. Viral genomic data allowed us to reconstruct mumps transmission links not evident from epidemiological data or standard single-gene surveillance efforts and also revealed connections between apparently unrelated mumps outbreaks

CR1 Knops blood group alleles are not associated with severe malaria in the Gambia

The Knops blood group antigen erythrocyte polymorphisms have been associated with reduced falciparum malaria-based in vitro rosette formation (putative malaria virulence factor). Having previously identified single-nucleotide polymorphisms (SNPs) in the human complement receptor 1 (CR1/CD35) gene underlying the Knops antithetical antigens Sl1/Sl2 and McC(a)/McC(b), we have now performed genotype comparisons to test associations between these two molecular variants and severe malaria in West African children living in the Gambia. While SNPs associated with Sl:2 and McC(b+) were equally distributed among malaria-infected children with severe malaria and control children not infected with malaria parasites, high allele frequencies for Sl 2 (0.800, 1,365/1,706) and McC(b) (0.385, 658/1706) were observed. Further, when compared to the Sl 1/McC(a) allele observed in all populations, the African Sl 2/McC(b) allele appears to have evolved as a result of positive selection (modified Nei-Gojobori test Ka-Ks/s.e.=1.77, P-value &lt;0.05). Given the role of CR1 in host defense, our findings suggest that Sl 2 and McC(b) have arisen to confer a selective advantage against infectious disease that, in view of these case-control study data, was not solely Plasmodium falciparum malaria. Factors underlying the lack of association between Sl 2 and McC(b) with severe malaria may involve variation in CR1 expression levels

Unbiased Deep Sequencing of RNA Viruses from Clinical Samples

Here we outline a next-generation RNA sequencing protocol that enables de novo assemblies and intra-host variant calls of viral genomes collected from clinical and biological sources. The method is unbiased and universal; it uses random primers for cDNA synthesis and requires no prior knowledge of the viral sequence content. Before library construction, selective RNase H-based digestion is used to deplete unwanted RNA — including poly(rA) carrier and ribosomal RNA — from the viral RNA sample. Selective depletion improves both the data quality and the number of unique reads in viral RNA sequencing libraries. Moreover, a transposase-based 'tagmentation' step is used in the protocol as it reduces overall library construction time. The protocol has enabled rapid deep sequencing of over 600 Lassa and Ebola virus samples-including collections from both blood and tissue isolates-and is broadly applicable to other microbial genomics studies