459 research outputs found

    Congenital anomalies from a physics perspective. The key role of "manufacturing" volatility

    Full text link
    Genetic and environmental factors are traditionally seen as the sole causes of congenital anomalies. In this paper we introduce a third possible cause, namely random "manufacturing" discrepancies with respect to ``design'' values. A clear way to demonstrate the existence of this component is to ``shut'' the two others and to see whether or not there is remaining variability. Perfect clones raised under well controlled laboratory conditions fulfill the conditions for such a test. Carried out for four different species, the test reveals a variability remainder of the order of 10%-20% in terms of coefficient of variation. As an example, the CV of the volume of E.coli bacteria immediately after binary fission is of the order of 10%. In short, ``manufacturing'' discrepancies occur randomly, even when no harmful mutation or environmental factors are involved. Not surprisingly, there is a strong connection between congenital defects and infant mortality. In the wake of birth there is a gradual elimination of defective units and this screening accounts for the post-natal fall of infant mortality. Apart from this trend, post-natal death rates also have humps and peaks associated with various inabilities and defects.\qL In short, infant mortality rates convert the case-by-case and mostly qualitative problem of congenital malformations into a global quantitative effect which, so to say, summarizes and registers what goes wrong in the embryonic phase. Based on the natural assumption that for simple organisms (e.g. rotifers) the manufacturing processes are shorter than for more complex organisms (e.g. mammals), fewer congenital anomalies are expected. Somehow, this feature should be visible on the infant mortality rate. How this conjecture can be tested is outlined in our conclusion.Comment: 43 pages, 9 figure

    The Duals of *-Operator Frames for End*A(H)

    Get PDF
    Frames play significant role in signal and image processing, which leads to many applications in differents fields. In this paper we define the dual of ∗-operator frames and we show their propreties obtained in Hilbert A-modules and we establish some results

    Autoantibodies against cardiac β(1)-adrenoceptor do not affect the low-affinity state β(1)-adrenoceptor-mediated inotropy in rat cardiomyocytes

    Get PDF
    Circulating autoantibodies directed against the 2nd extracellular loop (EL-2) of β(1)-adrenoceptors (β(1)-AABs) have been detected in the serum of patients with various cardiovascular pathologies. β(1)-AABs induce agonistic, positive inotropic effects via β(1)-adrenoceptors (β(1)ARs). In the mammalian heart, β(1)-AR can exist in 2 distinct activated configurations (the so-called high- and low-affinity states). The aim of the present study was to investigate whether the action of β(1)-AAB is dependent on the affinity state of β(1)AR in isolated ventricular cardiomyocytes of adult Wistar rats. Immunoglobulin G (IgG) containing β(1)-AAB obtained from animals immunized with a peptide corresponding to the EL-2 of human β(1)-AR, caused a dose-dependent increase in cell shortening. Isoproterenol-induced inotropy was significantly reduced in cardiomyocytes that had been preincubated with IgG containing β(1)-AAB and in cardiomyocytes isolated from immunized rats. The negative effects of preincubation with IgG containing β(1)-AAB on the response to isoproterenol was inhibited in the presence of bisoprolol. CGP 12177A and pindolol-induced inotropy was not affected by IgG preincubation or immunization. No detectable inotropic effect of cell shortening was obtained with IgG containing β(1)-AAB in the presence of propranolol and 3-isobutyl-1-methylxanthine. The present study demonstrates that β(1)-AABs have no agonist/antagonist-like effects upon low-affinity state β(1)-ARs. This result indicates that β(1)-AABs recognize and stabilize the high-affinity state, but are unable to stabilize and (or) induce the low-affinity state receptor

    Species composition of sand flies and bionomics of Phlebotomus papatasi and P. sergenti (Diptera: Psychodidae) in cutaneous leishmaniasis endemic foci, Morocco

    Get PDF
    Detailed data set for sand fly species sampled in 48 sites across Morocco from April to June 2013. The specimens were sorted as male or female for each species. The coordinates (longitude and latitude) for each site is also presented in this data set. (XLSX 23 kb

    Chemical composition, antimicrobial, antioxidant and anticancer activities of essential oil from Ammodaucus leucotrichus Cosson & Durieu (Apiaceae) growing in South Algeria

    Get PDF
    ABSTRACT. The chemical composition of the essential oil obtained by hydrodistillation from aerial parts of A. leucotrichus Cosson & Durieu (Apiaceae) grown in the south of Algeria (El-Oued) was determined by GC-MS analysis. The oil was found to be rich in perilladehyde 64.66% and D-Limonene 26.99%. The biological activity of A. leucotrichus Cosson & Durieu essential oil has been investigated. The in vitro antimicrobial activity of the essential oil sample was tested on eight strains, one yeast and one fungi. The test showed interesting antimicrobial properties, especially on Salmonella enterica and E. coli, the antioxidant capacity of the oil was measured using the cyclic voltammetry, and the AAT value of A. leucotrichus essential oil was evaluated 47.84 mg α-TE/L. In addition, the antitumor activity showed that the oil of A. leucotrichus was very significant against the HCT116 colon cancer cell line.               KEY WORDS: Ammodaucus leucotrichus, Antioxidant activity, Anticancer activity, Cyclic voltammetry Bull. Chem. Soc. Ethiop. 2019, 33(3), 541-549. DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

    Antibodies against the second extracellular loop of β1-adrenergic receptors induce endothelial dysfunction in conductance and resistance arteries of the Wistar rat

    Get PDF
    Autoantibodies against β1-adrenoceptors (β1-ARs) have been detected in the serum of patients with various cardiac diseases; however, the pathological impact of these autoantibodies (β1-AABs) has only been evaluated in cardiac tissue. The purpose of the present study was to evaluate whether β1-AABs have deleterious effects on vascular reactivity in rats. An enzyme-linked immunosorbent assay was used to detect β1-AABs in sera from immunized rats over a period of 1–3 months using the peptidic sequence of the second extracellular loop of human β1-AR. Functional studies were performed in thoracic aortic (TA) and small mesenteric artery (SMA) rings from immunized rats. Following pre-contraction with phenylephrine (0.3 μM and 3 μM for the TA and SMA respectively), cumulative concentration–response curves (CCRCs) to various β-AR agonists (isoproterenol, dobutamine, salbutamol, SR 58611A), acetylcholine, A23187, and sodium nitroprusside (SNP) were then plotted. The relaxations induced by dobutamine, SR 58611A, and acetylcholine were significantly impaired, but salbutamol-induced relaxations were not affected, in both vessels from immunized rats. A significant impairment of isoproterenol-induced relaxation was only observed in SMA. CCRCs to SNP were not modified in either of the vessels. A23187-induced relaxation was impaired in immunized rats. Following pretreatment with l-arginine, vasorelaxation to acetylcholine and SR 58611A was restored in immunized rats. This study demonstrates that immunization against the second extracellular loop of β1-ARs has a deleterious impact on vasorelaxations in the TA and SMA of rats, involving alterations in endothelium-dependent NO signaling pathways
    corecore