1,738 research outputs found
Rapid decrease in titer and breadth of neutralizing anti-HCV antibodies in HIV/HCV-coinfected patients who achieved SVR
The main targets for neutralizing anti-hepatitis C virus (HCV) antibodies (HCV-nAbs) are the E1 and E2
envelope glycoproteins. We have studied the characteristics of HCV-nAbs through a retrospective study
involving 29 HIV/HCV-coinfected patients who achieved sustained virological response (SVR) with pegIFNα+ribavirin anti-HCV therapy. Plasma samples at baseline and week 24 after SVR were used to
perform neutralization assays against fve JFH1-based HCV recombinant viruses coding for E1 and E2
from genotypes 1a (H77), 1b (J4), 2a (JFH1), 3a (S52) and 4a (ED43). At baseline, the majority of plasma
samples neutralized 1a, 1b, 2a, and 4a, but not 3a, genotypes. Twenty-four weeks following SVR, most
neutralizing titers declined substantially. Furthermore, titers against 3a and 2a were not detected in
many patients. Plasma samples with high HCV-nAb titers neutralized all genotypes, and the highest
titers at the starting point correlated with the highest titers at week 24 after SVR. In conclusion, high
titers of broad-spectrum HCV-nAbs were detected in HIV/HCV-coinfected individuals, however, those
titers declined soon after SVRThis study was supported by grants from Instituto de Salud Carlos III (ISCIII; grant
numbers PI14/01094 and PI17/00657 to JB, PI17/00903 to JGG, PI14CIII/00011 and PI17CIII/00003 to SR) and
Ministerio de Sanidad, Servicios Sociales e Igualdad (grant number EC11-241). Te study was also funded by the
RD16CIII/0002/0002, RD16/0025/0018, and RD16/0025/0017 projects as part of the Plan Nacional R+D+I
and co-funded by ISCIII- Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional
(FEDER
Human-mediated dispersal of seeds by the airflow of vehicles
Human-mediated dispersal is known as an important driver of long-distance dispersal for plants but underlying mechanisms
have rarely been assessed. Road corridors function as routes of secondary dispersal for many plant species but the extent to which vehicles support this process remains unclear. In this paper we quantify dispersal distances and seed deposition of plant species moved over the ground by the slipstream of passing cars. We exposed marked seeds of four species on a section of road and drove a car along the road at a speed of 48 km/h. By tracking seeds we quantified movement parallel as well as lateral to the road, resulting dispersal kernels, and the effect of repeated vehicle passes. Median distances travelled by seeds along the road were about eight meters for species with wind dispersal morphologies and one meter for species without such adaptations. Airflow created by the car lifted seeds and resulted in longitudinal dispersal. Single seeds reached our maximum measuring distance of 45 m and for some species exceeded distances under primary dispersal. Mathematical
models were fit to dispersal kernels. The incremental effect of passing vehicles on longitudinal dispersal decreased with
increasing number of passes as seeds accumulated at road verges. We conclude that dispersal by vehicle airflow facilitates seed movement along roads and accumulation of seeds in roadside habitats. Dispersal by vehicle airflow can aid the spread of plant species and thus has wide implications for roadside ecology, invasion biology and nature conservation
MLP: a MATLAB toolbox for rapid and reliable auditory threshold estimation
In this paper, we present MLP, a MATLAB toolbox enabling auditory
thresholds estimation via the adaptive Maximum Likelihood procedure proposed
by David Green (1990, 1993). This adaptive procedure is particularly appealing for
those psychologists that need to estimate thresholds with a good degree of accuracy
and in a short time. Together with a description of the toolbox, the current text
provides an introduction to the threshold estimation theory and a theoretical
explanation of the maximum likelihood adaptive procedure. MLP comes with a
graphical interface and it is provided with several built-in, classic psychoacoustics
experiments ready to use at a mouse click
Prenatal and Postnatal Tobacco Exposure and Behavioral Problems in 10-Year-Old Children: Results from the GINI-plus Prospective Birth Cohort Study
BACKGROUND: Prenatal and postnatal tobacco exposure have been reported to be associated with behavioral problems. However, the magnitude of the association with tobacco exposure at specific periods of exposure is unclear. OBJECTIVE: We assessed the relative risk of behavioral problems in children who had been exposed to tobacco smoke in utero and postnatally. METHODS: We analyzed data from a prospective birth cohort study in two cities in Germany: the German Infant Nutrition Intervention. Our sample included 5,991 children born between 1995 and 1998 as well as their parents. We measured behavioral problems using the Strength and Difficulties Questionnaire (SDQ) at follow-up 10 years after birth. According to prespecified SDQ cutoff values, children were classified as "normal," "borderline," or "abnormal" according to the subscales "emotional symptoms," "conduct problems," "hyperactivity/inattention," "peer-relationship problems," and a total difficulties score. Smoke exposure and further covariates were assessed using parent questionnaires. RESULTS: Compared with children not exposed to tobacco smoke, children exposed both pre- and postnatally to tobacco smoke had twice the estimated risk [95% confidence interval (CI), 1.4-3.1] of being classified as abnormal according to the total difficulties score of the SDQ at 10 years of age. Children who were only prenatally exposed had a 90% higher relative risk (95% CI, 0.9-4.0), whereas children who were only postnatally exposed had a 30% higher relative risk (95% CI, 0.9-1.9). These results could not be explained by confounding by parental education, father's employment, child's time spent in front of computer or television screen, being a single father or mother, or mother's age. CONCLUSIONS: Prenatal exposure to tobacco smoke is associated with behavioral problems in school-age children. Although our findings do not preclude the influence of postnatal exposure, prenatal exposure seems to be more important
Cognitive loading affects motor awareness and movement kinematics but not locomotor trajectories during goal-directed walking in a virtual reality environment.
The primary purpose of this study was to investigate the effects of cognitive loading on movement kinematics and trajectory formation during goal-directed walking in a virtual reality (VR) environment. The secondary objective was to measure how participants corrected their trajectories for perturbed feedback and how participants' awareness of such perturbations changed under cognitive loading. We asked 14 healthy young adults to walk towards four different target locations in a VR environment while their movements were tracked and played back in real-time on a large projection screen. In 75% of all trials we introduced angular deviations of ±5° to ±30° between the veridical walking trajectory and the visual feedback. Participants performed a second experimental block under cognitive load (serial-7 subtraction, counter-balanced across participants). We measured walking kinematics (joint-angles, velocity profiles) and motor performance (end-point-compensation, trajectory-deviations). Motor awareness was determined by asking participants to rate the veracity of the feedback after every trial. In-line with previous findings in natural settings, participants displayed stereotypical walking trajectories in a VR environment. Our results extend these findings as they demonstrate that taxing cognitive resources did not affect trajectory formation and deviations although it interfered with the participants' movement kinematics, in particular walking velocity. Additionally, we report that motor awareness was selectively impaired by the secondary task in trials with high perceptual uncertainty. Compared with data on eye and arm movements our findings lend support to the hypothesis that the central nervous system (CNS) uses common mechanisms to govern goal-directed movements, including locomotion. We discuss our results with respect to the use of VR methods in gait control and rehabilitation
The psychophysics of uneconomical choice: non-linear reward evaluation by a nectar feeder
Uneconomical choices by humans or animals that evaluate reward options challenge the expectation that decision-makers always maximize the return currency. One possible explanation for such deviations from optimality is that the ability to sense differences in physical value between available alternatives is constrained by the sensory and cognitive processes for encoding profitability. In this study, we investigated the capacity of a nectarivorous bat species (Glossophaga commissarisi) to discriminate between sugar solutions with different concentrations. We conducted a two-alternative free-choice experiment on a population of wild electronically tagged bats foraging at an array of computer-automated artificial flowers that recorded individual choices. We used a Bayesian approach to fit individual psychometric functions, relating the strength of preferring the higher concentration option to the intensity of the presented stimulus. Psychometric analysis revealed that discrimination ability increases non-linearly with respect to intensity. We combined this result with a previous psychometric analysis of volume perception. Our theoretical analysis of choice for rewards that vary in two quality dimensions revealed regions of parameter combinations where uneconomic choice is expected. Discrimination ability may be constrained by non-linear perceptual and cognitive encoding processes that result in uneconomical choice
Mixing quantum and classical mechanics and uniqueness of Planck's constant
Observables of quantum or classical mechanics form algebras called quantum or
classical Hamilton algebras respectively (Grgin E and Petersen A (1974) {\it J
Math Phys} {\bf 15} 764\cite{grginpetersen}, Sahoo D (1977) {\it Pramana} {\bf
8} 545\cite{sahoo}). We show that the tensor-product of two quantum Hamilton
algebras, each characterized by a different Planck's constant is an algebra of
the same type characterized by yet another Planck's constant. The algebraic
structure of mixed quantum and classical systems is then analyzed by taking the
limit of vanishing Planck's constant in one of the component algebras. This
approach provides new insight into failures of various formalisms dealing with
mixed quantum-classical systems. It shows that in the interacting mixed
quantum-classical description, there can be no back-reaction of the quantum
system on the classical. A natural algebraic requirement involving restriction
of the tensor product of two quantum Hamilton algebras to their components
proves that Planck's constant is unique.Comment: revised version accepted for publication in J.Phys.A:Math.Phy
Effects of HCV Eradication on Bone mineral density in HIV/HCV Coinfected Patients
Little is known about the effects of eradication of HCV on bone mineral density (BMD) and biomarkers of bone remodeling in HIV/HCV coinfected patients.
We prospectively assessed standardized BMD (sBMD) at the lumbar spine and femoral neck, World Health Organization (WHO) BMD categories at both sites, and plasma concentrations of soluble receptor activator of nuclear factor-kappaβ ligand (sRANKL), and osteoprotegerin (OPG) at baseline (the date of initiation of anti-HCV therapy) and at 96 weeks.
A total of 238 patients were included, median age 49.5 years, 76.5% males, 48.3% with cirrhosis, 98.3% on antiretroviral therapy, median CD4+ cell count 527 cells/mm 3, 86.6% with HIV-1 RNA < 50 copies/mL. The prevalence of osteoporosis at baseline at the lumbar spine (LS) and femoral neck (FN) was 17.6% and 7.2%, respectively. Anti-HCV therapy comprised pegylated interferon and ribavirin (PegIFN-RBV) plus one direct-acting antiviral in 53.4%, PegIFN-RBV in 34.5%, and sofosbuvir/RBV in 12.2%. A total of 145 (60.9%) patients achieved sustained viral response (SVR). No significant effect of SVR was observed on sBMD for the interaction between time and SVR either in the LS (P=0.801) or the FN (P=0.911). Likewise, no significant effect of SVR was observed in plasma levels of sRANKL (P=0.205), OPG (P=0.249), and sRANKL/OPG ratio (P=0.123) for the interaction between time and SVR. No significant correlation was found between fibrosis by transient elastography, and LS and FN sBMD, at baseline, and week 96.
SVR was not associated with significant changes in BMD nor biomarkers of bone remodeling in HIV/HCV-coinfected persons.This study was supported by Instituto de Salud Carlos III (ISCII), grant numbers PI11/01556, PI14/01094, PI14/01581, and PI14CIII/00011, and by Ministerio de Sanidad, Servicios Sociales e Igualdad, grant number EC11-241. The study was also funded by the RD16/0025/0017, RD16/0025/0018 and RD16CIII/0002/0002 projects as part of the Plan Nacional R + D + I and cofunded by ISCIII-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER).S
Dual checkpoint blockade of CD47 and LILRB1 enhances CD20 antibody-dependent phagocytosis of lymphoma cells by macrophages
Antibody-dependent cellular phagocytosis (ADCP) by macrophages, an important effector function of tumor targeting antibodies, is hampered by ‘Don´t Eat Me!’ signals such as CD47 expressed by cancer cells. Yet, human leukocyte antigen (HLA) class I expression may also impair ADCP by engaging leukocyte immunoglobulin-like receptor subfamily B (LILRB) member 1 (LILRB1) or LILRB2. Analysis of different lymphoma cell lines revealed that the ratio of CD20 to HLA class I cell surface molecules determined the sensitivity to ADCP by the combination of rituximab and an Fc-silent variant of the CD47 antibody magrolimab (CD47-IgGσ). To boost ADCP, Fc-silent antibodies against LILRB1 and LILRB2 were generated (LILRB1-IgGσ and LILRB2-IgGσ, respectively). While LILRB2-IgGσ was not effective, LILRB1-IgGσ significantly enhanced ADCP of lymphoma cell lines when combined with both rituximab and CD47-IgGσ. LILRB1-IgGσ promoted serial engulfment of lymphoma cells and potentiated ADCP by non-polarized M0 as well as polarized M1 and M2 macrophages, but required CD47 co-blockade and the presence of the CD20 antibody. Importantly, complementing rituximab and CD47-IgGσ, LILRB1-IgGσ increased ADCP of chronic lymphocytic leukemia (CLL) or lymphoma cells isolated from patients. Thus, dual checkpoint blockade of CD47 and LILRB1 may be promising to improve antibody therapy of CLL and lymphomas through enhancing ADCP by macrophages
Boceprevir plus pegylated interferon/ribavirin to re-treat hepatitis C virus genotype 1 in HIV-HCV co-infected patients: final results of the Spanish BOC HIV-HCV Study
Introduction Boceprevir (BOC) was one of the first oral inhibitors of hepatitis C virus (HCV) NS3 protease to be developed. This study assessed the safety and efficacy of BOC + pegylated interferon-α2a/ribavirin (PEG-IFN/RBV) in the retreatment of HIV-HCV co-infected patients with HCV genotype 1. Methods This was a phase III prospective trial. HIV-HCV (genotype 1) co-infected patients from 16 hospitals in Spain were included. These patients received 4 weeks of PEG-IFN/RBV (lead-in), followed by response-guided therapy with PEG-IFN/RBV plus BOC (a fixed 44 weeks was indicated in the case of cirrhosis). The primary endpoint was the sustained virological response (SVR) rate at 24 weeks post-treatment. Efficacy and safety were evaluated in all patients who received at least one dose of the study drug. Results From June 2013 to April 2014, 102 patients were enrolled, 98 of whom received at least one treatment dose. Seventy-three percent were male, 34% were cirrhotic, 23% had IL28b CC, 65% had genotype 1a, and 41% were previous null responders. The overall SVR rate was 67%. Previous null-responders and cirrhotic patients had lower SVR rates (57% and 51%, respectively). Seventy-six patients (78%) completed the therapy scheme; the most common reasons for discontinuation were lack of response at week 12 (12 patients) and adverse events (six patients). Conclusions Response-guided therapy with BOC in combination with PEG-IFN/RBV led to an overall SVR rate of 67%, but an SVR rate of only 51% in patients with cirrhosis. The therapy was generally well tolerated. Although the current standards of care do not include BOC + PEG-IFN/RBV, the authors believe that this combination can be beneficial in situations where new HCV direct antiviral agent interferon-free therapies are not available yet
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