740 research outputs found
Postnatal β2 adrenergic treatment improves insulin sensitivity in lambs with IUGR but not persistent defects in pancreatic islets or skeletal muscle
Placental insufficiency causes intrauterine growth restriction (IUGR) and disturbances in glucose homeostasis with associated β adrenergic receptor (ADRβ) desensitization. Our objectives were to measure insulin-sensitive glucose metabolism in neonatal lambs with IUGR and to determine whether daily treatment with ADRβ2 agonist and ADRβ1/β3 antagonists for 1 month normalizes their glucose metabolism. Growth, glucose-stimulated insulin secretion (GSIS) and glucose utilization rates (GURs) were measured in control lambs, IUGR lambs and IUGR lambs treated with adrenergic receptor modifiers: clenbuterol atenolol and SR59230A (IUGR-AR). In IUGR lambs, islet insulin content and GSIS were less than in controls; however, insulin sensitivity and whole-bodyGUR were not different from controls.Of importance, ADRβ2 stimulation with β1/β3 inhibition increases both insulin sensitivity and whole-body glucose utilization in IUGR lambs. In IUGR and IUGR-AR lambs, hindlimb GURs were greater but fractional glucose oxidation rates and ex vivo skeletal muscle glucose oxidation rates were lower than controls. Glucose transporter 4 (GLUT4) was lower in IUGR and IUGR-AR skeletal muscle than in controls but GLUT1 was greater in IUGR-AR. ADRβ2, insulin receptor, glycogen content and citrate synthase activity were similar among groups. In IUGR and IUGR-AR lambs heart rates were greater, which was independent of cardiac ADRβ1 activation. We conclude that targeted ADRβ2 stimulation improved whole-body insulin sensitivity but minimally affected defects in GSIS and skeletal muscle glucose oxidation. We show that risk factors for developing diabetes are independent of postnatal catch-up growth in IUGR lambs as early as 1 month of age and are inherent to the islets and myocytes
Postnatal β2 adrenergic treatment improves insulin sensitivity in lambs with IUGR but not persistent defects in pancreatic islets or skeletal muscle
Placental insufficiency causes intrauterine growth restriction (IUGR) and disturbances in glucose homeostasis with associated β adrenergic receptor (ADRβ) desensitization. Our objectives were to measure insulin-sensitive glucose metabolism in neonatal lambs with IUGR and to determine whether daily treatment with ADRβ2 agonist and ADRβ1/β3 antagonists for 1 month normalizes their glucose metabolism. Growth, glucose-stimulated insulin secretion (GSIS) and glucose utilization rates (GURs) were measured in control lambs, IUGR lambs and IUGR lambs treated with adrenergic receptor modifiers: clenbuterol atenolol and SR59230A (IUGR-AR). In IUGR lambs, islet insulin content and GSIS were less than in controls; however, insulin sensitivity and whole-bodyGUR were not different from controls.Of importance, ADRβ2 stimulation with β1/β3 inhibition increases both insulin sensitivity and whole-body glucose utilization in IUGR lambs. In IUGR and IUGR-AR lambs, hindlimb GURs were greater but fractional glucose oxidation rates and ex vivo skeletal muscle glucose oxidation rates were lower than controls. Glucose transporter 4 (GLUT4) was lower in IUGR and IUGR-AR skeletal muscle than in controls but GLUT1 was greater in IUGR-AR. ADRβ2, insulin receptor, glycogen content and citrate synthase activity were similar among groups. In IUGR and IUGR-AR lambs heart rates were greater, which was independent of cardiac ADRβ1 activation. We conclude that targeted ADRβ2 stimulation improved whole-body insulin sensitivity but minimally affected defects in GSIS and skeletal muscle glucose oxidation. We show that risk factors for developing diabetes are independent of postnatal catch-up growth in IUGR lambs as early as 1 month of age and are inherent to the islets and myocytes
Revisiting the ecology and evolution of burying beetle behavior (Staphylinidae: Silphinae)
Abstract Investigating fundamental processes in biology requires the ability to ground broad questions in species-specific natural history. This is particularly true in the study of behavior because an organism's experience of the environment will influence the expression of behavior and the opportunity for selection. Here, we provide a review of the natural history and behavior of burying beetles of the genus Nicrophorus to provide the groundwork for comparative work that showcases their remarkable behavioral and ecological diversity. Burying beetles have long fascinated scientists because of their well-developed parenting behavior, exhibiting extended post-hatching care of offspring that varies extensively within and across taxa. Despite the burgeoning success of burying beetles as a model system for the study of behavioral evolution, there has not been a review of their behavior, ecology, and evolution in over 25?years. To address this gap, we leverage a developing community of researchers who have contributed to a detailed knowledge of burying beetles to highlight the utility of Nicrophorus for investigating the causes and consequences of social and behavioral evolution
A pilot study for augmenting atomoxetine with methylphenidate: safety of concomitant therapy in children with attention-deficit/hyperactivity disorder
<p>Abstract</p> <p>Background</p> <p>This study examined augmenting atomoxetine with extended-release methylphenidate in children whose attention-deficit/hyperactivity disorder (ADHD) previously failed to respond adequately to stimulant medication.</p> <p>Methods</p> <p>Children with ADHD and prior stimulant treatment (<it>N </it>= 25) received atomoxetine (1.2 mg/kg/day) plus placebo. After 4 weeks, patients who were responders (<it>n </it>= 4) were continued on atomoxetine/placebo while remaining patients were randomly assigned to either methylphenidate (ATX/MPH) (1.1 mg/kg/day) or placebo augmentation (ATX/PB) for another 6 weeks. Patients and sites were blind to timing of active augmentation. Safety measures included vital signs, weight, and adverse events. Efficacy was assessed by ADHD rating scales.</p> <p>Results</p> <p>Categorical increases in vital signs occurred for 5 patients (3 patients in ATX/MPH, 2 patients in ATX/PBO). Sixteen percent discontinued the study due to AE, but no difference between augmentation groups. Atomoxetine treatment was efficacious on outcome measures (<it>P </it>≤ .001), but methylphenidate did not enhance response.</p> <p>Conclusion</p> <p>Methylphenidate appears to be safely combined with atomoxetine, but conclusions limited by small sample. With atomoxetine treatment, 43% of patients achieved normalization on ADHD ratings.</p
THE PRESENT STATUS OF THE GERM-CELL PROBLEM IN VERTEBRATES
(i) Morphological studies relating to the origin and differentiation of the definitive germ cells in vertebrates have, as indicated, resulted in conflicting views. In many instances two or more competent investigators who have studied the same form have reached different conclusions. (2) Some contend that the germ cells are set aside from the soma during the early stages of embryonic development, and that these alone serve as the progenitors of the functional sex cells. (3) Others recognize an early differentiation of sex cells but hold that these are supplemented by others produced from the somatic epithelium of the gonad in late embryonic or post-embryonic stages. (4) Another group recognizes the early differentiated cells as germ cells but contend that these all degenerate and that the definitive ones are formed from the germinal epithelium. These degenerating germ cells are believed by certain authors to be a phylogenetic recapitulation of the condition in lower forms. (5) Finally, yet another group contends that the so-called primordial germ cells are not germ cells at all but are enlarged cells in some stage of mitosis or in some specific metabolic phase. This group believes that all germ cells are derived from the somatic cells of the germinal epithelium. (6) Experimental work supports the view that the primordial germ cells, which are recognized early, are the progenitors of the definitive sex cells. When these primordial germ cells are prevented from reaching the site of the developing gonad the individual fails to develop sex cells, although a sterile gonad and its associated structures may develop. (7) I suggest that the observed proliferation of germ cells from the germinal epithelium, reported by numerous investigators, can be interpreted in another way by a thorough study of the enlarged germ cells in relation to the epithelium. It seems probable that the cells of the epithelium, which form functional sex elements, are not and never were a part of the mesothelial covering, but are cells which were segregated early, and are merely stored in the epithelium.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74677/1/j.1469-185X.1945.tb00313.x.pd
Coupled evolution of temperature and carbonate chemistry during the Paleocene–Eocene; new trace element records from the low latitude Indian Ocean
This is the final version. Available on open access from Elsevier via the DOI in this recordThe early Paleogene represents the most recent interval in Earth’s history characterized by global
greenhouse warmth on multi-million year timescales, yet our understanding of long-term climate and
carbon cycle evolution in the low latitudes, and in particular the Indian Ocean, remains very poorly
constrained. Here we present the first long-term sub-eccentricity-resolution stable isotope (δ13 30 C and
δ
18 O) and trace element (Mg/Ca and B/Ca) records spanning the late Paleocene–early Eocene (~58–
53 Ma) across a surface–deep hydrographic reconstruction of the northern Indian Ocean, resolving
late Paleocene 405-kyr paced cyclicity and a portion of the PETM recovery. Our new records reveal a
long-term warming of ~4–5°C at all depths in the water column, with absolute surface ocean
temperatures and magnitudes of warming comparable to the low latitude Pacific. As a result of
warming, we observe a long-term increase in δ
18 Osw of the mixed layer, implying an increase in net
evaporation. We also observe a collapse in the temperature gradient between mixed layer- and
thermocline-dwelling species from ~57–54 Ma, potentially due to either the development of a more
homogeneous water column with a thicker mixed layer, or depth migration of the Morozovella in
response to warming. Synchronous warming at both low and high latitudes, along with decreasing
B/Ca ratios in planktic foraminifera indicating a decrease in ocean pH and/or increasing dissolved
inorganic carbon, suggest that global climate was forced by rising atmospheric CO2 concentrations
during this time.European Consortium for Ocean Research Drilling (ECORD)International Association of Sedimentologists (IAS)NSFNatural Environment Research Council (NERC
Remodelling of Cortical Actin Where Lytic Granules Dock at Natural Killer Cell Immune Synapses Revealed by Super-Resolution Microscopy
Super-resolution 3D imaging reveals remodeling of the cortical actin meshwork at the natural killer cell immune synapse, which is likely to be important for secretion of lytic granules
Differential Effects of Early- and Late-Life Access to Carotenoids on Adult Immune Function and Ornamentation in Mallard Ducks (Anas platyrhynchos)
Environmental conditions early in life can affect an organism’s phenotype at adulthood, which may be tuned to perform optimally in conditions that mimic those experienced during development (Environmental Matching hypothesis), or may be generally superior when conditions during development were of higher quality (Silver Spoon hypothesis). Here, we tested these hypotheses by examining how diet during development interacted with diet during adulthood to affect adult sexually selected ornamentation and immune function in male mallard ducks (Anas platyrhynchos). Mallards have yellow, carotenoid-pigmented beaks that are used in mate choice, and the degree of beak coloration has been linked to adult immune function. Using a 2×2 factorial experimental design, we reared mallards on diets containing either low or high levels of carotenoids (nutrients that cannot be synthesized de novo) throughout the period of growth, and then provided adults with one of these two diets while simultaneously quantifying beak coloration and response to a variety of immune challenges. We found that both developmental and adult carotenoid supplementation increased circulating carotenoid levels during dietary treatment, but that birds that received low-carotenoid diets during development maintained relatively higher circulating carotenoid levels during an adult immune challenge. Individuals that received low levels of carotenoids during development had larger phytohemagglutinin (PHA)-induced cutaneous immune responses at adulthood; however, dietary treatment during development and adulthood did not affect antibody response to a novel antigen, nitric oxide production, natural antibody levels, hemolytic capacity of the plasma, or beak coloration. However, beak coloration prior to immune challenges positively predicted PHA response, and strong PHA responses were correlated with losses in carotenoid-pigmented coloration. In sum, we did not find consistent support for either the Environmental Matching or Silver Spoon hypotheses. We then describe a new hypothesis that should be tested in future studies examining developmental plasticity
The effector T cell response to influenza infection
Influenza virus infection induces a potent initial innate immune response, which serves to limit the extent of viral replication and virus spread. However, efficient (and eventual) viral clearance within the respiratory tract requires the subsequent activation, rapid proliferation, recruitment, and expression of effector activities by the adaptive immune system, consisting of antibody producing B cells and influenza-specific T lymphocytes with diverse functions. The ensuing effector activities of these T lymphocytes ultimately determine (along with antibodies) the capacity of the host to eliminate the viruses and the extent of tissue damage. In this review, we describe this effector T cell response to influenza virus infection. Based on information largely obtained in experimental settings (i.e., murine models), we will illustrate the factors regulating the induction of adaptive immune T cell responses to influenza, the effector activities displayed by these activated T cells, the mechanisms underlying the expression of these effector mechanisms, and the control of the activation/differentiation of these T cells, in situ, in the infected lungs
Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an
Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis
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