4 resultados para anchor

em DigitalCommons@The Texas Medical Center


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INFLUENCE OF ANCHORING ON MISCARRIAGE RISK PERCEPTION ASSOCIATED WITH AMNIOCENTESIS Publication No. ___________ Regina Nuccio, BS Supervisory Professor: Claire N. Singletary, MS, CGC Amniocentesis is the most common invasive procedure performed during pregnancy (Eddleman, et al., 2006). One important factor that women consider when making a decision about amniocentesis is the risk of miscarriage associated with the procedure. People use heuristics such as anchoring, the action of using a prior belief regarding the magnitude of risk as a frame of reference for new information to be synthesized, to better understand risks that they encounter in their lives. This study aimed to determine a woman’s perception of miscarriage risk associated with amniocentesis before and after a genetic counseling session and to determine what factors are most likely to anchor a woman’s perception of miscarriage risk associated with amniocentesis. Most women perceived the risk as low or average pre-counseling and were likely to indicate the numeric risk of amniocentesis as <1% risk. A higher percentage of patients correctly identified the numeric risk as <1% post-counseling when compared to pre-counseling. However, the majority of patients’ feeling about the risk perception did not change after the genetic counseling session (60%), regardless of how they perceived the risk before discussing amniocentesis with a genetic counselor. Those whose risk perception did change after discussing amniocentesis with a genetic counselor showed a decreased risk perception (p<0.0001). Of the multitude of factors studied, only two showed significance: having a friend or relative with a personal or family history of a genetic disorder was associated with a lower risk perception (p=0.001) and having a child already was associated with a lower risk perception (p=0.038). The lack of significant factors may reflect the uniqueness of each patient’s heuristic framework and reinforces the importance of genetic counseling to elucidate individual concerns.

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In many organisms, polarity of the oocyte is established post-transcriptionally via subcellular RNA localization. Many RNAs are localized during oogenesis in Xenopus laevis, including Xlsirts ( Xenopus laevis short interspersed repeat transcripts) [Kloc, 1993]. Xlsirts constitute a large family defined by highly homologous repeat units 79–81 nucleotides in length. Endogenous Xlsirt RNAs use the METRO (Message Transport Organizer) pathway of localization, where RNAs are transported from the nucleus to the mitochondrial cloud in stage I oocytes. Secondly, RNAs anchor at the vegetal pole in stage II oocytes. Exogenous Xlsirt RNAs can also utilize the Late pathway of localization, which involves localization to the vegetal cortex during stage III of oogenesis and results in RNAs anchored in the cortex of the entire vegetal hemisphere. ^ The Xlsirts localization signal is contained within the repeat region. This study was designed to test the hypothesis that there are cis -acting localization elements in Xlsirts, and that higher order structure plays a role. Results of experiments on Xlsirt P11, a 1700 basepair (bp) family member, led to the conclusion that a 137-bp fragment of the repetitive region is necessary and sufficient for METRO and Late pathway localization. This analysis definitively demonstrates that the Xlsirt localization signal for the METRO and Late pathways reside within the repetitive region and not within the flanking regions. Analysis of Xlsirt linker scanning mutations revealed two METRO-pathway specific subelements, and one Late-pathway specific subelement. Functional, computer, and biochemical evidence relates the higher order structure of this element to its ability to function as a localization element. ^ Xlsirt 137 is 99% identical to the Xlsirt consensus sequence identified in this study, suggesting that it is the localization element for all localized Xlsirt family members. The repeat unit was reframed based on function, rather than arbitrarily based on sequence. This work supports the hypothesis presented in 1981 by George Spohr, who originally isolated the Xlsirts, which stated that the highly conserved repetitive elements must be constrained from variability due to some unknown function of the repeats themselves. These studies shed light on the mechanism of RNA localization, linking structure and function. ^

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Adenylyl cyclase (AC) converts ATP into cAMP, which activates protein kinase A (PKA). Activation of PKA leads to the phosphorylation of specific substrates. The mechanism of specificity of PKA phosphorylation baffled researchers for many years. The discovery of A Kinase Anchoring Proteins (AKAPs) has helped to unravel this mystery. AKAPs function to target PKA to specific regions within the cell. They also anchor other enzymes, receptors, or channels leading to tightly regulated signaling modules. Several studies have suggested an important role for activated PKA in these complexes, including the AKAPs yotiao and muscle AKAP (mAKAP). Yotiao, a plasma membrane AKAP, anchors PP1, NMDA receptors, IP3 receptors, and heart potassium channel subunit KCNQI. PKA phosphorylation of NMDA receptors as well as KCNQI leads to increased channel activity. Patients with mutations in KCNQI or yotiao that cause loss of targeting of KCNQI develop long QT syndrome, which can be fatal. mAKAP anchors several CAMP/PKA-regulated pathways to the nuclear envelope in cardiac myocytes. The necessity of activated PKA in these complexes led to the hypothesis that AC is also anchored. The results indicate that AC does associate with yotiao in brain and heart, specifically with AC types I-III, and IX. Co-expression of AC II or III with yotiao leads to inhibition of each isoform's activity. Binding assays revealed that yotiao binds to the N-terminus of AC II and that this region can reverse the inhibition of AC II, but not AC III, indicating unique binding sites on yotiao. AC II binds directly to as 808-957 of yotiao. Y808-957 acts as a dominant negative as the addition of it to rat brain membranes results in a ∼40% increase in AC activity. Additionally, AC was also found to associate with mAKAP in heart, specifically with AC types II and V. The binding site of AC was mapped to 275-340 of mAKAP, while mAKAP binds to the soluble domains of AC V as a complex. These results indicate that interactions between AC and AKAPs are specific and that AC plays an important role in AKAP-targeted signaling. ^

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Objectives. Minimal Important Differences (MIDs) establish benchmarks for interpreting mean differences in clinical trials involving quality of life outcomes and inform discussions of clinically meaningful change in patient status. As such, the purpose of this study was to assess MIDs for the Functional Assessment of Cancer Therapy–Melanoma (FACT-M). ^ Methods. A prospective validation study of the FACT-M was performed with 273 patients with stage I to IV melanoma. FACT-M, Karnofsky Performance Status (KPS), and Eastern Cooperative Oncology Group Performance Status (ECOG-PS) scores were obtained at baseline and 3 months following enrollment. Anchor- and distribution-based methods were used to assess MIDs, and the correspondence between MID ranges derived from each method was evaluated. ^ Results. This study indicates that an approximate range for MIDs of the FACT-M subscales is between 5 to 8 points for the Trial Outcome Index, 4 to 5 points for the Melanoma Combined Subscale, 2 to 4 points for the Melanoma Subscale, and 1 to 2 points for the Melanoma Surgery Subscale. Each method produced similar but not identical ranges of MIDs. ^ Conclusions. The properties of the anchor instrument employed to derive MIDs directly affect resulting MID ranges and point values. When MIDs are offered as supportive evidence of a clinically meaningful change, the anchor instrument used to derive thresholds should be clearly stated along with evidence supporting the choice of anchor instrument as the most appropriate for the domain of interest. In this analysis, the KPS was a more appropriate measure than the ECOG-PS for assessing MIDs. ^