251 research outputs found
Characterization of transgene expression in adenoviral vector-based HIV-1 vaccine candidates
Recombinant adenovirus vectors have been extensively used in gene therapy clinical studies. More recently, the capability of inducing potent cell-mediated and humoral immunity has made these vectors equally attractive candidates for prophylactic or therapeutic vaccine applications. Merck and Co., Inc., developed HIV-1 vaccine candidates based on adenovirus serotype 5 (Ad5) vectors in which the E1 gene, a critical component for adenovirus replication, was replaced by the cytomegalovirus immediate/early promoter, followed by mutated versions of the HIV-1 gag, pol or nef genes (constructs referred to as MRKAd5gag, MRKAd5pol and MRKAd5nef, respectively). Vaccine performance was evaluated in vitro in a novel assay that measures the level of transgene expression in non-permissive A549 cells. Various combinations of vectors were studied. The results indicate that the vaccine induces a dose-dependent expression of the HIV-1 transgenes in vitro. Furthermore, the gag, pol, and nef transgenes are expressed differentially in A549 cells in an MOI-dependent and formulation-dependent manner, yielding an unexpected enhancement of protein expression in trivalent vs. monovalent formulations. Our data suggest that the presence of additional virus in multivalent formulations increases individual transgene expression in A549 cells, even when the amount of DNA encoding the gene of interest remains constant. This enhancement appears to be controlled at the transcriptional level and related to both the total amount of virus and the combination of transgenes present in the formulation
Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables
One of the main results of Scale Relativity as regards the foundation of
quantum mechanics is its explanation of the origin of the complex nature of the
wave function. The Scale Relativity theory introduces an explicit dependence of
physical quantities on scale variables, founding itself on the theorem
according to which a continuous and non-differentiable space-time is fractal
(i.e., scale-divergent). In the present paper, the nature of the scale
variables and their relations to resolutions and differential elements are
specified in the non-relativistic case (fractal space). We show that, owing to
the scale-dependence which it induces, non-differentiability involves a
fundamental two-valuedness of the mean derivatives. Since, in the scale
relativity framework, the wave function is a manifestation of the velocity
field of fractal space-time geodesics, the two-valuedness of velocities leads
to write them in terms of complex numbers, and yields therefore the complex
nature of the wave function, from which the usual expression of the
Schr\"odinger equation can be derived.Comment: 36 pages, 5 figures, major changes from the first version, matches
the published versio
Assessing Validity and Bias of Within- Person Variability in Affect and Personality
Within-person variability in affect (e.g., Neuroticism) and personality have been linked to well-being. These are measured either by asking people to report how variable they are or to give multiple reports on the construct and calculating a within-person standard deviation adjusted for confounding by the person-level mean. The two measures are weakly correlated with one another and the links of variability with well-being depend on which measure researchers use. Recent research suggests that people’s repeated ratings may be biased by response styles. In a 7-day study (N = 399) with up to five measurements per day, we confirmed that the measures of variability lacked sufficient convergent validity to be used interchangeably. We found only 1 significant correlation (of 10) between variability in repeated ratings of affect or personality and variability in repeated ratings of a theoretically unrelated construct (i.e., features of images). There was very little evidence supporting the response styles hypothesis
Backreaction of superhorizon perturbations in scalar field cosmologies
It has been suggested that the acceleration of the Universe may be due to the
backreaction of perturbations to the Friedmann-Robertson-Walker background. For
a Universe dominated by cold dark matter, it is known that the backreaction of
superhorizon perturbations can not drive acceleration. We extend this result to
models with cold dark matter together with a scalar field. We show that the
scalar field can drive acceleration only via the standard mechanism of a
constant or nearly constant piece of its potential (i.e., a cosmological
constant); there is no separate mechanism involving superhorizon backreaction.
This rules out some models which have been proposed in the literature.Comment: 5 page
Health utility values of breast cancer treatments and the impact of varying quality of life assumptions on cost-effectiveness
In breast cancer research, utility assumptions are outdated and inconsistent which may affect the results of quality adjusted life year (QALY) calculations and thereby cost-effectiveness analyses (CEAs). Four hundred sixty four female patients with breast cancer treated at Erasmus MC, the Netherlands, completed EQ-5D-5L questionnaires from diagnosis throughout their treatment. Average utilities were calculated stratified by age and treatment. These utilities were applied in CEAs analysing 920 breast cancer screening policies differing in eligible ages and screening interval simulated by the MISCAN-Breast microsimulation model, using a willingness-to-pay threshold of €20,000. The CEAs included varying sets on normative, breast cancer treatment and screening and follow-up utilities. Efficiency frontiers were compared to assess the impact of the utility sets. The calculated average patient utilities were reduced at breast cancer diagnosis and 6 months after surgery and increased toward normative utilities 12 months after surgery. When using normative utility values of 1 in CEAs, QALYs were overestimated compared to using average gender and age-specific values. Only small differences in QALYs gained were seen when varying treatment utilities in CEAs. The CEAs varying screening and follow-up utilities showed only small changes in QALYs gained and the efficiency frontier. Throughout all variations in utility sets, the optimal strategy remained robust; biennial for ages 40-76 years and occasionally biennial 40-74 years. In sum, we recommend to use gender and age stratified normative utilities in CEAs, and patient-based breast cancer utilities stratified by age and treatment or disease stage. Furthermore, despite varying utilities, the optimal screening scenario seems very robust.</p
Health utility values of breast cancer treatments and the impact of varying quality of life assumptions on cost-effectiveness
In breast cancer research, utility assumptions are outdated and inconsistent which may affect the results of quality adjusted life year (QALY) calculations and thereby cost-effectiveness analyses (CEAs). Four hundred sixty four female patients with breast cancer treated at Erasmus MC, the Netherlands, completed EQ-5D-5L questionnaires from diagnosis throughout their treatment. Average utilities were calculated stratified by age and treatment. These utilities were applied in CEAs analysing 920 breast cancer screening policies differing in eligible ages and screening interval simulated by the MISCAN-Breast microsimulation model, using a willingness-to-pay threshold of €20,000. The CEAs included varying sets on normative, breast cancer treatment and screening and follow-up utilities. Efficiency frontiers were compared to assess the impact of the utility sets. The calculated average patient utilities were reduced at breast cancer diagnosis and 6 months after surgery and increased toward normative utilities 12 months after surgery. When using normative utility values of 1 in CEAs, QALYs were overestimated compared to using average gender and age-specific values. Only small differences in QALYs gained were seen when varying treatment utilities in CEAs. The CEAs varying screening and follow-up utilities showed only small changes in QALYs gained and the efficiency frontier. Throughout all variations in utility sets, the optimal strategy remained robust; biennial for ages 40-76 years and occasionally biennial 40-74 years. In sum, we recommend to use gender and age stratified normative utilities in CEAs, and patient-based breast cancer utilities stratified by age and treatment or disease stage. Furthermore, despite varying utilities, the optimal screening scenario seems very robust.</p
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Heart field origin of great vessel precursors relies on nkx2.5-mediated vasculogenesis
The pharyngeal arch arteries (PAAs) are transient embryonic blood vessels that make indispensable contributions to the carotid arteries and great vessels of the heart, including the aorta and pulmonary artery1, 2. During embryogenesis, the PAAs appear in a craniocaudal sequence to connect pre-existing segments of the primitive circulation after de novo vasculogenic assembly from angioblast precursors3, 4. Despite the unique spatiotemporal characteristics of PAA development, the embryonic origins of PAA angioblasts and the genetic factors regulating their emergence remain unknown. Here, we identify the embryonic source of PAA endothelium as nkx2.5+ progenitors in lateral plate mesoderm long considered to adopt cell fates within the heart exclusively5, 6. Further, we report that PAA endothelial differentiation relies on Nkx2.5, a canonical cardiac transcription factor not previously implicated in blood vessel formation. Together, these studies reveal the heart field origin of PAA endothelium and attribute a novel vasculogenic function to the cardiac transcription factor nkx2.5 during great vessel precursor development
Lower risk of peripheral venous catheter-related bloodstream infection by hand insertion
INTRODUCTION
Little is known about the bloodstream infection (BSI) risk associated with short-term peripheral venous catheters (PVCs) and no large study investigated the insertion site-related risk for PVC-BSI.
METHODS
We performed a cohort study at the University of Geneva Hospitals using the prospective hospital-wide BSI surveillance database. We analyzed the association between insertion site and risk of PVC-BSI on the upper extremity using univariable and multivariable marginal Cox models.
RESULTS
Between 2016 and 2020, utilization of 403'206 peripheral venous catheters were prospectively recorded in a 2000-bed hospital consortium with ten sites. Twenty-seven percent of PVC (n = 109'686) were inserted in the hand. After adjustment for confounding factors, hand insertion was associated with a decreased PVC-BSI risk (adjusted hazard ratio [HR] 0.42, 95% CI 0.18-0.98, p = 0.046) compared to more proximal insertion sites. In a sensitivity analysis for PVCs with ≥ 3 days of dwell time, we confirmed a decreased PVC-BSI risk after hand insertion (HR 0.37, 95% CI 0.15-0.93, p = 0.035).
CONCLUSION
Hand insertion should be considered for reducing PVC infections, especially for catheters with an expected dwell time of more than 2Â days
Indicators for wild animal offtake: methods and case study for African mammals and birds
Unsustainable exploitation of wild animals is one of the greatest threats to biodiversity and to millions of people depending on wild meat for food and income. The international conservation and development community has committed to implementing plans for sustainable use of natural resources and has requested development of monitoring systems of bushmeat offtake and trade. Although offtake monitoring systems and indicators for marine species are more developed, information on harvesting terrestrial species is limited. Building on approaches developed to monitor exploitation of fisheries and population trends, we have proposed two novel indicators for harvested terrestrial species: the mean body mass indicator (MBMI) assessing whether hunters are relying increasingly on smaller species over time, as a measure of defaunation, by tracking body mass composition of harvested species within samples across various sites and dates; and the offtake pressure indicator (OPI) as a measure of harvesting pressure on groups of wild animals within a region by combining multiple time series of the number of harvested individuals across species. We applied these two indicators to recently compiled data for West and Central African mammals and birds. Our exploratory analyses show that the MBMI of harvested mammals decreased but that of birds rose between 1966/1975 and 2010. For both mammals and birds the OPI increased substantially during the observed time period. Given our results, time-series data and information collated from multiple sources are useful to investigate trends in body mass of hunted species and offtake volumes. In the absence of comprehensive monitoring systems, we suggest that the two indicators developed in our study are adequate proxies of wildlife offtake, which together with additional data can inform conservation policies and actions at regional and global scales
Contribution of Type 2 Diabetes Mellitus to Subclinical Atherosclerosis in Subjects with Morbid Obesity
Introduction: Type 2 diabetes mellitus (T2DM) and obesity are both related to increased risk of cardiovascular disease and mortality. Early atherosclerotic vascular changes can be detected by non-invasive tests like carotid artery intima-media thickness (cIMT) and pulse wave velocity (PWV). Both cIMT and PWV are significantly impaired in T2DM patients and in obese patients, but the additional effect of T2DM on these vascular measurements in obese subjects has not been evaluated. Methods: Two hundred morbidly obese patients with or without T2DM were enrolled in a prospective cohort study and underwent extensive laboratory testing, including cIMT and PWV measurements. The cohort was divided into a group with and a group without T2DM. Results: Within this cohort, 43 patients (21.5%) were diagnosed with T2DM. These patients were older and had more often (a history of) hypertension as compared to patients without T2DM. HbA1c levels were significantly increased, while LDL cholesterol was significantly lower and the use of statins higher than in non-diabetic participants. cIMT and PWV were significantly increased in subjects suffering from T2DM. The variability in cIMT and PWV was related to differences in age and systolic blood pressure, but not to the presence of T2DM. Conclusion: While T2DM negatively affects the vasculature in morbid obesity, hypertension and age seem to be the major risk factors, independent from the presence of T2DM. Clinical Trial Registration: Dutch Trial Register NTR5172
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