Graded Response Model
Mostrando 13-24 de 29 artigos, teses e dissertações.
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13. Positive feedback in eukaryotic gene networks: cell differentiation by graded to binary response conversion
Feedback is a ubiquitous control mechanism of gene networks. Here, we have used positive feedback to construct a synthetic eukaryotic gene switch in Saccharomyces cerevisiae. Within this system, a continuous gradient of constitutively expressed transcriptional activator is translated into a cell phenotype switch when the activator is expressed autocatalytica
Oxford University Press.
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14. Computational insights into Caenorhabditis elegans vulval development
Studies of Caenorhabditis elegans vulval development provide a paradigm for pattern formation during animal development. The fates of the six vulval precursor cells are specified by the combined action of an inductive signal that activates the EGF receptor mitogen-activated PK signaling pathway (specifying a primary fate) and a lateral signal mediated by LIN
National Academy of Sciences.
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15. Comparative 13C and 31P NMR assessment of altered metabolism during graded reductions in coronary flow in intact rat hearts.
13C NMR spectroscopy may offer a unique ability to characterize the metabolic response to graded reduction in coronary flow since it allows repeated, nondestructive identification of products of intermediary metabolism in the same heart. The sensitivity of 13C parameters of glucose metabolism was compared with changes in levels of phosphocreatine, ATP, and p
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16. Hysteresis in a synthetic mammalian gene network
Bistable and hysteretic switches, enabling cells to adopt multiple internal expression states in response to a single external input signal, have a pivotal impact on biological systems, ranging from cell-fate decisions to cell-cycle control. We have designed a synthetic hysteretic mammalian transcription network. A positive feedback loop, consisting of a tra
National Academy of Sciences.
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17. Activation of Cl secretion during chemical hypoxia by endogenous release of adenosine in intestinal epithelial monolayers.
Intestinal ischemia is characterized by rapid early inhibition of absorptive function and the appearance of net secretion, although why active secretion persists in the setting of a mucosal energy deficit is unknown. The cryptlike epithelial line T84, a well-characterized model of intestinal Cl- secretion, develops a prominent increase in short-circuit curre
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18. Protection against group B meningococcal disease: evaluation of serotype 2 protein vaccines in a mouse bacteremia model.
A mouse bacteremia model was used to evaluate the immunogenicity and protection against challenge provided by five different meningococcal serotype 2 vaccines. Mice vaccinated with serotype 2 protein vaccines had levels of bacteremia reduced by at least 100-fold after challenge with group B serotype 2 miningococci. Mice vaccinated with serotype 2 protein vac
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19. Age-dependent regression analysis of male gonadal axis
The mechanisms by which aging progressively depletes testosterone (Te) availability in the male are unknown. Accordingly, the objective was to estimate brain gonadotropin-releasing hormone (GnRH) outflow (release and action), which cannot be observed directly, on the basis of downstream effects on pituitary luteinizing hormone (LH) secretion. LH, in turn, fe
American Physiological Society.
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20. Modulation of stimulus-secretion coupling in single rat gonadotrophs.
1. Exocytosis and intracellular [Ca2+] were determined simultaneously in single anterior pituitary gonadotrophs from ovariectomized female rats. Dispersed cells were cultured for 2-4 days with or without 0.2 nM oestradiol-17 beta (E2) before use. Cells were stimulated with either gonadotrophin releasing hormone (GnRH) or by membrane depolarization. Exocytosi
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21. Recombinant interleukin-6 protects mice against experimental bacterial infection.
Because of reports of high levels of interleukin-6 (IL-6) in patients during infection, we studied the role of IL-6 in experimental infection. Mice infected with the facultative intracellular pathogen Listeria monocytogenes displayed high levels of IL-6 in their sera and tissues, particularly the spleen, 1 to 3 days after infection. At this time, the IL-6 ti
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22. Akt induces enhanced myocardial contractility and cell size in vivo in transgenic mice
The serine-threonine kinase Akt seems to be central in mediating stimuli from different classes of receptors. In fact, both IGF-1 and IL6-like cytokines induce hypertrophic and antiapoptotic signals in cardiomyocytes through PI3K-dependent Akt activation. More recently, it was shown that Akt is involved also in the hypertrophic and antiapoptotic effects of �
National Academy of Sciences.
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23. Diabetogenic action of streptozotocin: relationship of dose to metabolic response
The relationship between the dose of intravenously administered streptozotocin (a N-nitroso derivative of glucosamine) and the diabetogenic response has been explored by use of the following indices of diabetogenic action: serum glucose, urine volume, and glycosuria, ketonuria, serum immunoreactive insulin (IRI), and pancreatic IRI content. Diabetogenic acti
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24. Experimentally derived model for the locomotor pattern generator in the Xenopus embryo.
1. Simulations of Xenopus embryo spinal neurons were endowed with Hodgkin-Huxley-style models of voltage-dependent Na+, Ca2+, slow K+ and fast K+ currents together with a Na(+)-dependent K+ current. The parameters describing the activation, inactivation and relaxation of these currents were derived from previous voltage-clamp studies of Xenopus embryo spinal