431 research outputs found
Effects of mutational loss of nucleoside kinases on deoxyadenosine 5'-phosphate/deoxyadenosine substrate cycle in cultured CEM and V79 cells.
The functions of a deoxynucleoside kinase and a deoxynucleotidase can give rise to substrate cycles in which the two enzymes catalyze in opposite directions the irreversible interconversion of a deoxynucleoside 5'-monophosphate (dNMP) and its deoxynucleoside. Earlier evidence showed that pyrimidine dNMP cycles occur in cultured cells and participate in the regulation of the size of dNMP pools there by affecting the transport of deoxyribonucleosides across the cell membrane. Here, we apply an isotope flow method using labeled adenine as precursor of dAMP and DNA to quantify deoxyadenosine excretion as a measure of the catabolic activity of a putative dAMP/deoxyadenosine cycle. A comparison of human CEM lymphoblasts and hamster V79 fibroblasts, including mutant cells lacking kinases for the phosphorylation of deoxyadenosine, shows a much lower deoxyadenosine excretion in CEM cells (0.05% of dATP synthesized by reduction of ADP) as compared with V79 cells (4% of dATP). Mutational loss of deoxycytidine kinase increases these values to 0.3% in CEM cells and to 10% in V79 cells. This strongly suggests the presence of a dAMP/deoxyadenosine cycle in both CEM and V79 cells. Additional loss of adenosine kinase only marginally affects deoxyadenosine excretion in CEM cells. The small excretion of deoxyadenosine (also in the absence of both kinases) demonstrates that in CEM cells the in situ activity of the deoxynucleotidase affecting the dAMP/deoxyadenosine substrate cycle is very low and that the cycle has mainly an anabolic function there
Parton distributions with threshold resummation
We construct a set of parton distribution functions (PDFs) in which
fixed-order NLO and NNLO calculations are supplemented with soft-gluon
(threshold) resummation up to NLL and NNLL accuracy respectively, suitable for
use in conjunction with any QCD calculation in which threshold resummation is
included at the level of partonic cross sections. These resummed PDF sets,
based on the NNPDF3.0 analysis, are extracted from deep-inelastic scattering,
Drell-Yan, and top quark pair production data, for which resummed calculations
can be consistently used. We find that, close to threshold, the inclusion of
resummed PDFs can partially compensate the enhancement in resummed matrix
elements, leading to resummed hadronic cross-sections closer to the fixed-order
calculation. On the other hand, far from threshold, resummed PDFs reduce to
their fixed-order counterparts. Our results demonstrate the need for a
consistent use of resummed PDFs in resummed calculations.Comment: 43 pages, 17 figures, accepted for publication in JHE
Effects of feeding low fishmeal diets with increasing soybean meal levels on growth, gut histology and plasma biochemistry of sea bass
The aquaculture industry depends upon the development of sustainable protein sources to replace fishmeal (FM) in aquafeeds and the products derived from soybeans are some of the most studied plant feedstuffs. A key area of investigation for continuing to improve modern aquafeeds includes the evaluation of varying proportions and combinations of plant ingredients to identify mixtures that are more efficiently utilized by the fish. This study investigated the effects of increasing soybean meal (SBM) by replacing a mix of plant ingredients in low FM (20%) diets on growth, blood biochemistry profile and gut histology on European sea bass. Five isonitrogenous and isolipidic experimental diets were formulated: four diets containing increasing SBM levels (0, 10, 20 and 30%; 0SBM, 10SBM, 20SBM and 30SBM, respectively) with a low content of FM (20%) and one control diet (0% SBM; 35% FM). Diets containing SBM brought to comparable performance and protein utilization, while 0SBM had negative impact on feed conversion rate and protein utilization. Blood parameters suggested an optimal nutritional status under all feeding treatments, even though slightly decreased values were reported at increasing dietary SBM. Histology examination did not show any changes indicative of soy-induced enteritis. We can conclude that for European sea bass: (i) different blends of plant protein did not affect feed intake despite the 20% FM dietary level; (ii) the inclusion of SBM maintains optimal growth and feed utilization in low FM diets; (iii) blood biochemistry profile showed a good nutritional status under all feeding regimes; (iv) no evidence of soy-induced enteritis was reported in any group fed low FM diets. For formulation of practical diets in on-growing of European sea bass, SBM up to 30% can be successfully incorporated into feeds containing low FM inclusion
Tailoring CD19xCD3-DART exposure enhances T-cells to eradication of B-cell neoplasms.
Many patients with B-cell malignancies can be successfully treated, although tumor eradication is rarely achieved. T-cell-directed killing of tumor cells using engineered T-cells or bispecific antibodies is a promising approach for the treatment of hematologic malignancies. We investigated the efficacy of CD19xCD3 DART bispecific antibody in a broad panel of human primary B-cell malignancies. The CD19xCD3 DART identified 2 distinct subsets of patients, in which the neoplastic lymphocytes were eliminated with rapid or slow kinetics. Delayed responses were always overcome by a prolonged or repeated DART exposure. Both CD4 and CD8 effector cytotoxic cells were generated, and DART-mediated killing of CD4+ cells into cytotoxic effectors required the presence of CD8+ cells. Serial exposures to DART led to the exponential expansion of CD4 + and CD8 + cells and to the sequential ablation of neoplastic cells in absence of a PD-L1-mediated exhaustion. Lastly, patient-derived neoplastic B-cells (B-Acute Lymphoblast Leukemia and Diffuse Large B Cell Lymphoma) could be proficiently eradicated in a xenograft mouse model by DART-armed cytokine induced killer (CIK) cells. Collectively, patient tailored DART exposures can result in the effective elimination of CD19 positive leukemia and B-cell lymphoma and the association of bispecific antibodies with unmatched CIK cells represents an effective modality for the treatment of CD19 positive leukemia/lymphoma
Transient receptor potential cation channel, subfamily V, member 4 and airway sensory afferent activation: Role of adenosine triphosphate
BackgroundSensory nerves innervating the airways play an important role in regulating various cardiopulmonary functions, maintaining homeostasis under healthy conditions and contributing to pathophysiology in disease states. Hypo-osmotic solutions elicit sensory reflexes, including cough, and are a potent stimulus for airway narrowing in asthmatic patients, but the mechanisms involved are not known. Transient receptor potential cation channel, subfamily V, member 4 (TRPV4) is widely expressed in the respiratory tract, but its role as a peripheral nociceptor has not been explored.ObjectiveWe hypothesized that TRPV4 is expressed on airway afferents and is a key osmosensor initiating reflex events in the lung.MethodsWe used guinea pig primary cells, tissue bioassay, in vivo electrophysiology, and a guinea pig conscious cough model to investigate a role for TRPV4 in mediating sensory nerve activation in vagal afferents and the possible downstream signaling mechanisms. Human vagus nerve was used to confirm key observations in animal tissues.ResultsHere we show TRPV4-induced activation of guinea pig airwayâspecific primary nodose ganglion cells. TRPV4 ligands and hypo-osmotic solutions caused depolarization of murine, guinea pig, and human vagus and firing of AÎŽ-fibers (not C-fibers), which was inhibited by TRPV4 and P2X3 receptor antagonists. Both antagonists blocked TRPV4-induced cough.ConclusionThis study identifies the TRPV4-ATP-P2X3 interaction as a key osmosensing pathway involved in airway sensory nerve reflexes. The absence of TRPV4-ATPâmediated effects on C-fibers indicates a distinct neurobiology for this ion channel and implicates TRPV4 as a novel therapeutic target for neuronal hyperresponsiveness in the airways and symptoms, such as cough
NLL soft and Coulomb resummation for squark and gluino production at the LHC
We present predictions of the total cross sections for pair production of
squarks and gluinos at the LHC, including the stop-antistop production process.
Our calculation supplements full fixed-order NLO predictions with resummation
of threshold logarithms and Coulomb singularities at next-to-leading
logarithmic (NLL) accuracy, including bound-state effects. The numerical effect
of higher-order Coulomb terms can be as big or larger than that of soft-gluon
corrections. For a selection of benchmark points accessible with data from the
2010-2012 LHC runs, resummation leads to an enhancement of the total inclusive
squark and gluino production cross section in the 15-30 % range. For individual
production processes of gluinos, the corrections can be much larger. The
theoretical uncertainty in the prediction of the hard-scattering cross sections
is typically reduced to the 10 % level.Comment: 45 pages, 16 Figures, LaTex. v2: published version. Grids with
numerical results for the NLL cross sections for squark and gluino production
at the 7/8 TeV LHC are included in the submission and are also available at
http://omnibus.uni-freiburg.de/~cs1010/susy.htm
Charm in Deep-Inelastic Scattering
We show how to extend systematically the FONLL scheme for inclusion of heavy quark mass effects in DIS to account for the possible effects of an intrinsic charm component in the nucleon. We show that when there is no intrinsic charm, FONLL is equivalent to S-ACOT to any order in perturbation theory, while when an intrinsic charm component is included FONLL is identical to ACOT, again to all orders in perturbation theory. We discuss in detail the inclusion of top and bottom quarks to construct a variable flavour number scheme, and give explicit expressions for the construction of the structure functions , and to NNLO
Delayed intracardial shunting and hypoxemia after massive pulmonary embolism in a patient with a biventricular assist device
We describe the interdisciplinary management of a 34-year-old woman with dilated cardiomyopathy three months postpartum on a cardiac biventricular assist device (BVAD) as bridge to heart transplantation with delayed onset of intracardial shunting and subsequent hypoxemia due to massive pulmonary embolism. After emergency surgical embolectomy pulmonary function was highly compromised (PaO2/FiO2 54) requiring bifemoral veno-venous extracorporeal membrane oxygenation. Transesophageal echocardiography detected atrial level hypoxemic right-to-left shunting through a patent foramen ovale (PFO). Percutaneous closure of the PFO was achieved with a PFO occluder device. After placing the PFO occluder device oxygenation increased significantly (Î paO2 119 Torr). The patient received heart transplantation 20 weeks after BVAD implantation and was discharged from ICU 3 weeks after transplantation
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