204 research outputs found
Statistical analysis plan for the LAKANA trial: a cluster-randomized, placebo-controlled, double-blinded, parallel group, three-arm clinical trial testing the effects of mass drug administration of azithromycin on mortality and other outcomes among 1–11-month-old infants in Mali
BACKGROUND:The Large-scale Assessment of the Key health-promoting Activities of two New mass drug administration regimens with Azithromycin (LAKANA) trial in Mali aims to evaluate the efficacy and safety of azithromycin (AZI) mass drug administration (MDA) to 1–11-month-old infants as well as the impact of the intervention on antimicrobial resistance (AMR) and mechanisms of action of azithromycin. To improve the transparency and quality of this clinical trial, we prepared this statistical analysis plan (SAP). METHODS/DESIGN: LAKANA is a cluster randomized trial that aims to address the mortality and health impacts of biannual and quarterly AZI MDA. AZI is given to 1–11-month-old infants in a high-mortality setting where a seasonal malaria chemoprevention (SMC) program is in place. The participating villages are randomly assigned to placebo (control), two-dose AZI (biannual azithromycin-MDA), and four-dose AZI (quarterly azithromycin-MDA) in a 3:4:2 ratio. The primary outcome of the study is mortality among the intention-to-treat population of 1–11-month-old infants. We will evaluate relative risk reduction between the study arms using a mixed-effects Poisson model with random intercepts for villages, using log link function with person-years as an offset variable. We will model outcomes related to secondary objectives of the study using generalized linear models with considerations on clustering. CONCLUSION: The SAP written prior to data collection completion will help avoid reporting bias and data-driven analysis for the primary and secondary aims of the trial. If there are deviations from the analysis methods described here, they will be described and justified in the publications of the trial results. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT04424511. Registered on 11 June 2020
Combined effects of human pressures on Europe’s marine ecosystems
Marine ecosystems are under high demand for human use, giving concerns about how pressures from human activities may affect their structure, function, and status. In Europe, recent developments in mapping of marine habitats and human activities now enable a coherent spatial evaluation of potential combined effects of human activities. Results indicate that combined effects from multiple human pressures are spread to 96% of the European marine area, and more specifically that combined effects from physical disturbance are spread to 86% of the coastal area and 46% of the shelf area. We compare our approach with corresponding assessments at other spatial scales and validate our results with European-scale status assessments for coastal waters. Uncertainties and development points are identified. Still, the results suggest that Europe’s seas are widely disturbed, indicating potential discrepancy between ambitions for Blue Growth and the objective of achieving good environmental status within the Marine Strategy Framework Directive
Phosphoproteome and drug-response effects mediated by the three protein phosphatase 2A inhibitor proteins CIP2A, SET, and PME-1
Protein phosphatase 2A (PP2A) critically regulates cell signaling and is a human tumor suppressor. PP2A complexes are modulated by proteins such as cancerous inhibitor of protein phosphatase 2A (CIP2A), protein phosphatase methylesterase 1 (PME-1), and SET nuclear proto-oncogene (SET) that often are deregulated in cancers. However, how they impact cellular phosphorylation and how redundant they are in cellular regulation is poorly understood. Here, we conducted a systematic phosphoproteomics screen for phosphotargets modulated by siRNA-mediated depletion of CIP2A, PME-1, and SET (to reactivate PP2A) or the scaffolding A-subunit of PP2A (PPP2R1A) (to inhibit PP2A) in HeLa cells. We identified PP2A-modulated targets in diverse cellular pathways, including kinase signaling, cytoskeleton, RNA splicing, DNA repair, and nuclear lamina. The results indicate nonredundancy among CIP2A, PME-1, and SET in phosphotarget regulation. Notably, PP2A inhibition or reactivation affected largely distinct phosphopeptides, introducing a concept of nonoverlapping phosphatase inhibition- and activation-responsive sites (PIRS and PARS, respectively). This phenomenon is explained by the PPP2R1A inhibition impacting primarily dephosphorylated threonines, whereas PP2A reactivation results in dephosphorylation of clustered and acidophilic sites. Using comprehensive drug-sensitivity screening in PP2A-modulated cells to evaluate the functional impact of PP2A across diverse cellular pathways targeted by these drugs, we found that consistent with global phosphoproteome effects, PP2A modulations broadly affect responses to more than 200 drugs inhibiting a broad spectrum of cancer-relevant targets. These findings advance our understanding of the phosphoproteins, pharmacological responses, and cellular processes regulated by PP2A modulation and may enable the development of combination therapies
Expression of hormone receptors in oropharyngeal squamous cell carcinoma
Hormone receptors play an important role in many types of cancers. Alongside factors associated with human papillomavirus (HPV) infection, hormonal receptors may impact the tumorigenesis of oropharyngeal cancer. This study consists of 199 consecutive oropharyngeal squamous cell carcinoma (OPSCC) patients diagnosed and treated with a curative intent. We examined androgen (AR), estrogen (ER; both alpha and beta), and progesterone receptor (PR) expressions using immunohistochemistry comparing tumor and patient characteristics. AR was expressed in 16%, PR in 27% and ER-beta in 63% of the tumors. HPV- and p16-positive tumors expressed more AR and less PR than their negative counterparts. High PR expression was associated with poor disease-specific and locoregional recurrence-free survival. AR, PR, and ER-beta are expressed in OPSCC, and AR and PR expressions are associated with HPV and p16 status. Furthermore, PR appears to have prognostic significance. This may allow us to investigate the role of anti-hormone receptors in the treatment of OPSCC.Peer reviewe
Loss of thalamic serotonin transporters in early drug-naïve Parkinson’s disease patients is associated with tremor: an [123I]β-CIT SPECT study
In vitro studies revealed serotonin transporter (5-HTT) decline in Parkinson’s disease (PD). Yet, few studies investigated thalamic 5-HTT in vivo and its effect on PD heterogeneity. We analyzed thalamic [123I]β-CIT binding (mainly reflecting 5-HTT binding) in 32 drug-naïve PD patients and 13 controls with SPECT. Twenty-six patients were examined twice (17 months apart). Based on UPDRS scores, we identified subgroups of patients with moderate/severe tremor (PDT) and without tremor (PDWT) at the time of clinical diagnosis. Additionally, depressive symptoms were evaluated using the Beck Depression Inventory (BDI) at baseline. Mean thalamic specific to non-specific [123I]β-CIT binding ratio was lower in patients when compared to controls, and further decreased during follow-up. At baseline, average thalamic ratio was significantly lower in the PDT than in the PDWT subgroup. No correlation was found between BDI scores and thalamic binding ratios. Our findings show decline of [123I]β-CIT binding to thalamic 5-HTT in PD and its possible contribution to tremor onset
Complexity Variability Assessment of Nonlinear Time-Varying Cardiovascular Control
The application of complex systems theory to physiology and medicine has provided meaningful information about the nonlinear aspects underlying the dynamics of a wide range of biological processes and their disease-related aberrations. However, no studies have investigated whether meaningful information can be extracted by quantifying second-order moments of time-varying cardiovascular complexity. To this extent, we introduce a novel mathematical framework termed complexity variability, in which the variance of instantaneous Lyapunov spectra estimated over time serves as a reference quantifier. We apply the proposed methodology to four exemplary studies involving disorders which stem from cardiology, neurology and psychiatry: Congestive Heart Failure (CHF), Major Depression Disorder (MDD), Parkinson?s Disease (PD), and Post-Traumatic Stress Disorder (PTSD) patients with insomnia under a yoga training regime. We show that complexity assessments derived from simple time-averaging are not able to discern pathology-related changes in autonomic control, and we demonstrate that between-group differences in measures of complexity variability are consistent across pathologies. Pathological states such as CHF, MDD, and PD are associated with an increased complexity variability when compared to healthy controls, whereas wellbeing derived from yoga in PTSD is associated with lower time-variance of complexity
Genome-wide Association Study of Long COVID
SummaryInfections can lead to persistent or long-term symptoms and diseases such as shingles after varicella zoster, cancers after human papillomavirus, or rheumatic fever after streptococcal infections1, 2. Similarly, infection by SARS-CoV-2 can result in Long COVID, a condition characterized by symptoms of fatigue and pulmonary and cognitive dysfunction3–5. The biological mechanisms that contribute to the development of Long COVID remain to be clarified. We leveraged the COVID-19 Host Genetics Initiative6, 7to perform a genome-wide association study for Long COVID including up to 6,450 Long COVID cases and 1,093,995 population controls from 24 studies across 16 countries. We identified the first genome-wide significant association for Long COVID at theFOXP4locus.FOXP4has been previously associated with COVID-19 severity6, lung function8, and cancers9, suggesting a broader role for lung function in the pathophysiology of Long COVID. While we identify COVID-19 severity as a causal risk factor for Long COVID, the impact of the genetic risk factor located in theFOXP4locus could not be solely explained by its association to severe COVID-19. Our findings further support the role of pulmonary dysfunction and COVID-19 severity in the development of Long COVID.</jats:p
Editing the genome of chicken primordial germ cells to introduce alleles and study gene function
With continuing advances in genome sequencing technology, the chicken genome
assembly is now better annotated with improved accuracy to the level of single
nucleotide polymorphisms. Additionally, the genomes of other birds such as the duck,
turkey and zebra finch have now been sequenced. A great opportunity exists in avian
biology to use genome editing technology to introduce small and defined sequence
changes to create specific haplotypes in chicken to investigate gene regulatory
function, and also perform rapid and seamless transfer of specific alleles between
chicken breeds. The methods for performing such precise genome editing are well
established for mammalian species but are not readily applicable in birds due to
evolutionary differences in reproductive biology.
A significant leap forward to address this challenge in avian biology was the
development of long-term culture methods for chicken primordial germ cells (PGCs).
PGCs present a cell line in which to perform targeted genetic manipulations that will
be heritable. Chicken PGCs have been successfully targeted to generate genetically
modified chickens. However, genome editing to introduce small and defined sequence
changes has not been demonstrated in any avian species. To address this deficit, the
application of CRISPR/Cas9 and short oligonucleotide donors in chicken PGCs for
performing small and defined sequence changes was investigated in this thesis.
Specifically, homology-directed DNA repair (HDR) using oligonucleotide donors
along with wild-type CRISPR/Cas9 (SpCas9-WT) or high fidelity CRISPR/Cas9
(SpCas9-HF1) was investigated in cultured chicken PGCs. The results obtained
showed that small sequences changes ranging from a single to a few nucleotides could
be precisely edited in many loci in chicken PGCs. In comparison to SpCas9-WT,
SpCas9-HF1 increased the frequency of biallelic and single allele editing to generate
specific homozygous and heterozygous genotypes. This finding demonstrates the
utility of high fidelity CRISPR/Cas9 variants for performing sequence editing with
high efficiency in PGCs.
Since PGCs can be converted into pluripotent stem cells that can potentially
differentiate into many cell types from the three germ layers, genome editing of PGCs
can, therefore, be used to generate PGC-derived avian cell types with defined genetic
alterations to investigate the host-pathogen interactions of infectious avian diseases.
To investigate this possibility, the chicken ANP32A gene was investigated as a target
for genetic resistance to avian influenza virus in PGC-derived chicken cell lines.
Targeted modification of ANP32A was performed to generate clonal lines of genome-edited
PGCs. Avian influenza minigenome replication assays were subsequently
performed in the ANP32A-mutant PGC-derived cell lines. The results verified that
ANP32A function is crucial for the function of both avian virus polymerase and
human-adapted virus polymerase in chicken cells. Importantly, an asparagine to
isoleucine mutation at position 129 (N129I) in chicken ANP32A failed to support
avian influenza polymerase function. This genetic change can be introduced into
chickens and validated in virological studies. Importantly, the results of my
investigation demonstrate the potential to use genome editing of PGCs as an approach
to generate many types of unique cell models for the study of avian biology.
Genome editing of PGCs may also be applied to unravel the genes that control the
development of the avian germ cell lineage. In the mouse, gene targeting has been
extensively applied to generate loss-of-function mouse models to use the reverse
genetics approach to identify key genes that regulate the migration of specified PGCs
to the genital ridges. Avian PGCs express similar cytokine receptors as their
mammalian counterparts. However, the factors guiding the migration of avian PGCs
are largely unknown. To address this, CRISPR/Cas9 was used in this thesis to generate
clonal lines of chicken PGCs with loss-of-function deletions in the CXCR4 and c-Kit
genes which have been implicated in controlling mouse PGC migration. The results
showed that CXCR4-deficient PGCs are absent from the gonads whereas c-Kit-deficient
PGCs colonise the developing gonads in reduced numbers and are
significantly reduced or absent from older stages. This finding shows a conserved role
for CXCR4 and c-Kit signalling in chicken PGC development. Importantly, other
genes suspected to be involved in controlling the development of avian germ cells can
be investigated using this approach to increase our understanding of avian reproductive
biology.
Finally, the methods developed in this thesis for editing of the chicken genome may
be applied in other avian species once culture methods for the PGCs from these species
are develope
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