Coarse-grained modeling study of nonpeptide RGD ligand density and PEG molecular weight on the conformation of poly(γ-glutamyl-glutamate) paclitaxel conjugates

Molecular shape, flexibility, and surface hydrophilicity are thought to influence the ability of nanoparticles to cross biological barriers during drug delivery. In this study, coarse-grained (CG) molecular dynamics (MD) simulations were used to study these properties of a polymer-drug construct in potential clinical development: poly(γ-glutamyl-glutamate)-paclitaxel-poly(ethylene glycol) nonpeptide RGD (PGG-PTX-PEG-npRGD), a linear glutamyl-glutamate polymer with paclitaxel and poly(ethylene glycol)-nonpeptide RGD side groups. It was hypothesized that the PEG molecular weight (MW) (500 Da; 1,000 Da; and 2,000 Da) and nonpeptide RGD ligand density (4, 8, 12, and 16 per molecule), respectively, may have advantageous effects on the shape, flexibility, and surface hydrophilicity of PGG-PTX-PEG-npRGD. Circular dichroism spectroscopy was used to suggest initial structures for the all-atom (AA) models of PGG-PTX-PEG-npRGD, which were further converted to CG models using a commercially available mapping algorithm. Due to its semi-flexibility, PGG-PTX-PEG-npRGD is not limited to one specific conformation. Thus, CG MD simulations were run until statistical equilibrium, at which PGG-PTX-PEG-npRGD is represented as an ensemble of statistically similar conformations. The size of a PGG-PTX-PEG-npRGD molecule is not affected by the PEG MW or the nonpeptide RGD density, but higher PEG MW results in increased surface density of a PGG-PTX-PEG-npRGD molecule. Most PGG-PTX-PEG-npRGD shapes are globular, although filamentous shapes were also observed in the PEG500 and PEG1000 molecules. PEG500 and PEG1000 molecules are more flexible than PEG2000 systems. A higher presence of npRGD ligands results in decrease surface hydrophilicity of PGG-PTX-PEG-npRGD. These results indicate that the PGG-PTX-PEG1000-npRGD4 and PGG-PTX-PEG1000-npRGD8 molecules are the most efficacious candidates and are further recommended for experimental preclinical studies

Geographic Life History Differences Predict Genomic Divergence Better than Mitochondrial Barcodes or Phenotype

Species diversity can be inferred using multiple data types, however, results based on genetic data can be at odds with patterns of phenotypic variation. Tiger beetles of the Cicindelidia politula (LeConte, 1875) species complex have been taxonomically problematic due to extreme phenotypic variation within and between populations. To better understand the biology and taxonomy of this group, we used mtDNA genealogies and multilocus nuclear analyses of 34,921 SNPs to elucidate its evolutionary history and evaluate the validity of phenotypically circumscribed species and subspecies. Genetic analyses recovered two divergent species that are also ecologically distinct, based on adult life history. These patterns are incongruous with the phenotypic variation that informed prior taxonomy, and most subspecies were not supported as distinct evolutionary lineages. One of the nominal subspecies was found to be a cryptic species; consequently, we elevate C. p. laetipennis (Horn, 1913) to a full species. Although nuclear and mtDNA datasets recovered broadly similar evolutionary units, mito-nuclear discordance was more common than expected, being observed between nearly all geographically overlapping taxonomic pairs. Additionally, a pattern of ‘mitochondrial displacement’ was observed, where mitochondria from one species unidirectionally displace others. Overall, we found that geographically associated life history factors better predict genomic divergence than phenotype and mitochondrial genealogies, and consequently taxon identifications based on mtDNA (e.g., DNA barcodes) may be misleading

Antagonism of STAT3 signalling by Ebola virus

Many viruses target signal transducers and activators of transcription (STAT) 1 and 2 to antagonise antiviral interferon signalling, but targeting of signalling by other STATs/cytokines, including STAT3/interleukin 6 that regulate processes important to Ebola virus (EBOV) haemorrhagic fever, is poorly defined. We report that EBOV potently inhibits STAT3 responses to interleukin-6 family cytokines, and that this is mediated by the interferon-antagonist VP24. Mechanistic analysis indicates that VP24 effects a unique strategy combining distinct karyopherin-dependent and karyopherin-independent mechanisms to antagonise STAT3-STAT1 heterodimers and STAT3 homodimers, respectively. This appears to reflect distinct mechanisms of nuclear trafficking of the STAT3 complexes, revealed for the first time by our analysis of VP24 function. These findings are consistent with major roles for global inhibition of STAT3 signalling in EBOV infection, and provide new insights into the molecular mechanisms of STAT3 nuclear trafficking, significant to pathogen-host interactions, cell physiology and pathologies such as cancer

Analysing the consistency of martian methane observations by investigation of global methane transport

Reports of methane on Mars at different times imply varying spatial distributions. This study examines whether different observations are mutually consistent by using a global circulation model to investigate the time evolution of methane in the atmosphere. Starting from an observed plume of methane, consistent with that reported in 2003 from ground-based telescopes, multiple simulations are analysed to investigate what is required for consistency with an inferred methane signal from the Thermal Emission Spectrometer made 60 sols later. The best agreement between the existing observations is found using continued release from a solitary source over Nili Fossae. While the peaks in methane over the Tharsis Montes, Elysium Mons and Nili Fossae regions are well aligned with the retrievals, an extra peak on the south flank of the Isidis basin is apparent in the model due to the prevailing eastward transport of methane. The absence of this feature could indicate the presence of a fast-acting localised sink of methane. These results show that the spatial and temporal variability of methane on Mars implied by observations could be explained by advection from localised time-dependent sources alongside a currently unknown methane sink. Evidence is presented that a fast trapping mechanism for methane is required. Trapping by a zeolite structure in dust particles is a suggested candidate warranting further investigation; this could provide a fast acting sink as required by this reconstruction

Thyroid Stimulating Hormone Receptor (TSHR) Intron 1 Variants Are Major Risk Factors for Graves' Disease in Three European Caucasian Cohorts

BACKGROUND: The thyroid stimulating hormone receptor (TSHR) gene is an established susceptibility locus for Graves' disease (GD), with recent studies refining association to two single nucleotide polymorphisms (SNPs), rs179247 and rs12101255, within TSHR intron 1. METHODOLOGY AND PRINCIPAL FINDINGS: We aimed to validate association of rs179247 and rs12101255 in Polish and UK Caucasian GD case-control subjects, determine the mode of inheritance and to see if association correlates with specific GD clinical manifestations. We investigated three case-control populations; 558 GD patients and 520 controls from Warsaw, Poland, 196 GD patients and 198 controls from Gliwice, Poland and 2504 GD patients from the UK National collection and 2784 controls from the 1958 British Birth cohort. Both rs179247 (P = 1.2×10(-2)-6.2×10(-15), OR = 1.38-1.45) and rs12101255 (P = 1.0×10(-4)-3.68×10(-21), OR = 1.47-1.87) exhibited strong association with GD in all three cohorts. Logistic regression suggested association of rs179247 is secondary to rs12101255 in all cohorts. Inheritance modeling suggested a co-dominant mode of inheritance in all cohorts. Genotype-phenotype correlations provided no clear evidence of association with any specific clinical characteristics. CONCLUSIONS: We have validated association of TSHR intron 1 SNPs with GD in three independent European cohorts and have demonstrated that the aetiological variant within the TSHR is likely to be in strong linkage disequilibrium with rs12101255. Fine mapping is now required to determine the exact location of the aetiological DNA variants within the TSHR

Comparison of IFCC-calibrated HbA1c from laboratory and point of care testing systems

Objective: WHO, IDF and ADA recommend HbA1c ≥6.5% (48 mmol/mol) for diagnosis of diabetes with pre-diabetes 6.0% (42 mmol/mol) [WHO] or 5.7% (39 mmol/mol) [ADA] to 6.4% (47 mmol/mol). We have compared HbA1c from several methods for research relating glycaemic markers.Research design and methods: HbA1c was measured in EDTA blood from 128 patients with diabetes on IE HPLC analysers (Bio-Rad Variant II NU, Menarini HA8160 and Tosoh G8), point of care systems, POCT, (A1cNow+ disposable cartridges and DCA 2000®+ analyser), affinity chromatography (Primus Ultra2) and the IFCC secondary reference method (Menarini HA8160 calibrated using IFCC SRM protocol).Results: median (IQ range) on IFCC SRM was 7.5% (6.8–8.4) (58(51–68) mmol/mol) HbA1c with minimum 5.3%(34 mmol/mol)/maximum 11.9%(107 mmol/mol). There were positive offsets between IFCC SRM and Bio-Rad Variant II NU, mean difference (1SD), +0.33%(0.17) (+3.6(1.9) mmol/mol), r2 = 0.984, p &lt; 0.001 and Tosoh G8, +0.22%(0.20) (2.4(2.2) mmol/mol), r2 = 0.976, p &lt; 0.001 with a very small negative difference −0.04%(0.11) (−0.4(1.2) mmol/mol), r2 = 0.992, p &lt; 0.001 for Menarini HA8160. POCT methods were less precise with negative offsets for DCA 2000®+ analyser −0.13%(0.28) (−1.4(3.1) mmol/mol), r2 = 0.955, p &lt; 0.001 and A1cNow+ cartridges −0.70%(0.67) (−7.7(7.3) mmol/mol), r2 = 0.699, p &lt; 0.001 (n = 113). Positive biases for Tosoh and Bio-Rad (compared with IFCC SRM) have been eliminated by subsequent revision of calibration.Conclusions: small differences observed between IFCC-calibrated and NGSP certified methods across a wide HbA1c range were confirmed by quality control and external quality assurance. As these offsets affect estimates of diabetes prevalence, the analyser (and calibrator) employed should be considered when evaluating diagnostic data.</p

Influence of arthritis and non-arthritis related factors on areal bone mineral density (BMDa) in women with longstanding inflammatory polyarthritis: a primary care based inception cohort

<p>Abstract</p> <p>Background</p> <p>The aim of this analysis was to determine the relative influence of disease and non-disease factors on areal bone mineral density (BMD_a) in a primary care based cohort of women with inflammatory polyarthritis.</p> <p>Methods</p> <p>Women aged 16 years and over with recent onset inflammatory polyarthritis were recruited to the Norfolk Arthritis Register (NOAR) between 1990 and 1993. Subjects were examined at both baseline and follow up for the presence of tender, swollen and deformed joints. At the 10^thanniversary visit, a sub-sample of women were invited to complete a bone health questionnaire and attend for BMD_a(Hologic, QDR 4000). Linear regression was used to examine the association between BMD_awith both (i) arthritis-related factors assessed at baseline and the 10^thanniversary visit and (ii) standard risk factors for osteoporosis. Adjustments were made for age.</p> <p>Results</p> <p>108 women, mean age 58.0 years were studied. Older age, decreasing weight and BMI at follow up were all associated with lower BMD_aat both the spine and femoral neck. None of the lifestyle factors were linked. Indices of joint damage including 10^thanniversary deformed joint count and erosive joint count were the arthritis-related variables linked with a reduction in BMD_aat the femoral neck. By contrast, disease activity as determined by the number of tender and or swollen joints assessed both at baseline and follow up was not linked with BMD_aat either site.</p> <p>Conclusion</p> <p>Cumulative disease damage was the strongest predictor of reduced femoral bone density. Other disease and lifestyle factors have only a modest influence.</p

Preclinical efficacy studies of a novel nanoparticle-based formulation of paclitaxel that out-performs Abraxane

Poly-(γ-l-glutamylglutamine)–paclitaxel (PGG–PTX) is a novel polymer-based formulation of paclitaxel (PTX) in which the PTX is linked to the polymer via ester bonds. PGG–PTX is of interest because it spontaneously forms very small nanoparticles in plasma. In mouse models, PGG–PTX increased tumor exposure to PTX by 7.7-fold relative to that produced by PTX formulated in Cremophor. In this study, the efficacy of PGG–PTX was compared to that of Abraxane, an established nanoparticular formulation of PTX, in three different tumor models. Efficacy was quantified by delay in tumor growth of NCI H460 human lung cancer, 2008 human ovarian cancer and B16 melanoma xenografts growing in athymic mice following administration of equitoxic doses of PGG–PTX and Abraxane administered on either a single dose or every 7 day schedule. Toxicity was assessed by change in total body weight. The efficacy and toxicity of PGG–PTX was shown to increase with dose in the H460 model. PGG–PTX was ~1.5-fold less potent than Abraxane. PGG–PTX produced statistically significantly greater inhibition of tumor growth than Abraxane in all three tumor models when mice were given single equitoxic doses of drug. When given every 7 days for 3 doses, PGG–PTX produced greater inhibition of tumor growth while generating much less weight loss in mice bearing H460 tumors. PGG–PTX has activity that is superior to that of Abraxane in multiple tumor models. PGG–PTX has the potential to out-perform Abraxane in enhancing the delivery of PTX tumors while at the same time further reducing the toxicity of both single dose and weekly treatment regimens

Estimation of returning Atlantic salmon st oc k from rod exploitation r at e f or pr incipal salmon r ivers in England &amp; Wales

F or eff ective fishery management, estimated stock sizes, along with their uncertainties, should be accurate, precise, and unbiased. Atlantic salmon Salmo salar stock assessment in England and Wales (and elsewhere across the Atlantic) estimate returning salmon stocks by applying a measure of rod exploitation rate (RER), derived from less abundant fishery-independent stock estimates, to abundant fishery-dependent data. Currently, RER estimates are generated for individual principal salmon rivers based on a v ailable local data and assumptions. We propose a single, consistent, transparent, and statistically robust method to estimate salmon stocks that transfers strength of information from "data-rich"rivers, i.e. those with fisheries-independent data, to "data-poor"rivers without such data. We proposed, fitted, simplified, and then validated a Beta-Binomial model of RER, including co v ariates representing angler and fish beha viours, riv er flo w, and random effects to control for nuisance effects. Our "best"model re v ealed co v ariate effects in line with our h ypotheses and generaliz ed to data not used to train it. We used this model to extrapolate stock estimates from 12 data-rich to 52 data-poor rivers, together with their uncertainties. The resulting river-specific salmon stock estimates were judged to be useful and can be used as key inputs to river-specific, national, and international salmon stock assessments

Risk factors for genital infections in people initiating SGLT2 inhibitors and their impact on discontinuation

Introduction: To identify risk factors, absolute risk, and impact on treatment discontinuation of genital infections with sodium-glucose co-transporter-2 inhibitors (SGLT2i). Research design and methods: We assessed the relationship between baseline characteristics and genital infection in 21 004 people with type 2 diabetes initiating SGLT2i and 55 471 controls initiating dipeptidyl peptidase-4 inhibitors (DPP4i) in a UK primary care database. We assessed absolute risk of infection in those with key risk factors and the association between early genital infection and treatment discontinuation. Results: Genital infection was substantially more common in those treated with SGLT2i (8.1% within 1 year) than DPP4i (1.8%). Key predictors of infection with SGLT2i were female sex (HR 3.64; 95% CI 3.23 to 4.11) and history of genital infection; &lt;1 year before initiation (HR 4.38; 3.73 to 5.13), 1–5 years (HR 3.04; 2.64 to 3.51), and &gt;5 years (HR 1.79; 1.55 to 2.07). Baseline HbA1c was not associated with infection risk for SGLT2i, in contrast to DPP4i where risk increased with higher HbA1c. One-year absolute risk of genital infection with SGLT2i was highest for those with a history of prior infection (females 23.7%, males 12.1%), compared with those without (females 10.8%, males 2.7%). Early genital infection was associated with a similar discontinuation risk for SGLT2i (HR 1.48; 1.21–1.80) and DPP4i (HR 1.58; 1.21–2.07). Conclusions: Female sex and history of prior infection are simple features that can identify subgroups at greatly increased risk of genital infections with SGLT2i therapy. These data can be used to risk-stratify patients. High HbA1c is not a risk factor for genital infections with SGLT2i