880 resultados para Rejection Sensitivity
Resumo:
This study examined the relation between ethnically based rejection sensitivity and academic achievement in a sample of 936 immigrant students in Germany and Switzerland. The theory of race-based rejection sensitivity that originated in North America was extended to immigrant students in Europe. The rough political climate against immigrants in Europe makes it probable that immigrant youth face particular difficulties and are affected by ethnically based rejection sensitivity, at least as much as—or even more than—minority youth in the United States. Using a standardized literacy performance test and multilevel analyses, we found that ethnically based rejection sensitivity was negatively related to academic achievement for immigrant students. This relation was partially mediated by a strong contingency of the students' self-worth on the heritage culture, as well as by a low number of native German or Swiss majority-group friends. We interpret these processes as immigrant students' efforts to cope with ethnically based rejection sensitivity by retracting into their heritage culture and avoiding majority-group contact, which unfortunately, however, at the same time also results in lower academic achievement. Copyright © 2014 John Wiley & Sons, Ltd.
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Dating aggression is common among emerging adults, and women who experience aggression from a dating partner are at risk for elevated depression and posttraumatic stress (Dutton et al., 2006). Although some women end their relationships as a result of aggression, other women remain committed to their partner, and aggression tends to escalate over time. The current study explored the role that depression and posttraumatic stress play in ending aggressive dating relationships as well as changes in these symptoms after ending such a relationship. The current study also sought to identify factors predictive of individual differences in emerging adults' commitment to their aggressive dating relationships. A sample of 148 emerging adult women currently in an aggressive dating relationship completed questionnaires about themselves and their relationship; measures of rejection sensitivity, self-worth, and romantic relational style were included as predictors of the Investment Model variables (e.g., investment, satisfaction, quality of alternatives, and commitment; Rusbult, 1980). Two assessments were completed six months apart. Neither depression nor posttraumatic stress predicted ending an aggressive relationship. However, ending an aggressive relationship was associated with experiencing less physical aggression, which mediated reductions in posttraumatic stress. A more avoidant romantic style indirectly predicted commitment through relationship satisfaction and investment. Both commitment and rejection sensitivity significantly predicted continuing an aggressive relationship six months later.
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The authors forward the hypothesis that social exclusion is experienced as painful because reactions to rejection are mediated by aspects of the physical pain system. The authors begin by presenting the theory that overlap between social and physical pain was an evolutionary development to aid social animals in responding to threats to inclusion. The authors then review evidence showing that humans demonstrate convergence between the 2 types of pain in thought, emotion, and behavior, and demonstrate, primarily through nonhuman animal research, that social and physical pain share common physiological mechanisms. Finally, the authors explore the implications of social pain theory for rejection-elicited aggression and physical pain disorders.
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Past HIV interventions have been critiqued for their failure to incorporate relational factors linked to condom use. Furthermore, few studies have focused on the relational context of sexual risk behavior among adolescents at elevated risk for HIV/STI exposure in the context of substance use. Therefore, this study evaluated the influence of three key relational factors (rejection sensitivity, intimacy dating goals, intercourse-related anxiety) salient for understanding condom use among adolescents in outpatient substance abuse treatment in South Florida. Structural equation modeling was used to test relational factors as direct and indirect predictors of condom use. Specifically, the current study investigated the influence of rejection sensitivity and intimacy dating goals on percentage of protected intercourse, with intercourse-related anxiety modeled as a mediator of this association. ^ Results obtained from the hypothesized structural model suggest rejection sensitivity and intimacy dating goals are significant predictors of percentage of protected intercourse. As expected, rejection sensitivity was related to lower levels of percentage of protected intercourse via heightened levels of intercourse-related anxiety and was not related directly to percentage of protected intercourse. Intercourse-related anxiety was indicated as a partial mediator between rejection sensitivity and percentage of protected intercourse. In contrast, intimacy dating goals was related to lower levels of percentage of protected intercourse directly. The findings demonstrate the importance of relational factors in condom use among adolescents in outpatient substance abuse treatment. Levels of protected intercourse are likely to increase when relational factors are targeted among adolescents in this high-risk population. Implications for prevention strategies targeting this high-risk subgroup of adolescents are discussed. ^
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BACKGROUND: Prospective testing for posttransplant circulating anti-HLA antibodies seems to be a critical noninvasive tool, but confirmatory data are lacking. MATERIALS AND METHODS: Over the last 3 years, peritubular capillary (PTC) C4d deposition was prospectively sought by an immunofluorescence technique applied to frozen tissue in biopsies obtained for allograft dysfunction. Screening for circulating anti-HLA class I/II alloantibodies (AlloAb) by the flow cytometric test was performed simultaneously. RESULTS: We evaluated 132 sets of biopsies and simultaneous serum samples. PTC C4d deposition was demonstrated in 15.9% (21/132) of biopsies. Circulating anti-HLA I/II AlloAb were detected in 25% (33/132) of serum samples. Employing receiver-operator characteristic (ROC) curves for all C4d-positive biopsies, screening for AlloAb showed a global specificity of 82% and sensitivity of 61.9%. When this analysis was restricted to biopsies obtained in the first month posttransplantation, the sensitivity increased to 81.8%, but the specificity decreased to 76.9%. After the first month posttransplantation, we observed sensitivity of 40.0% and a specificity of 86.4%. In the first month posttransplantation, all patients with a diagnosis of acute antibody-mediated rejection displayed circulating anti-HLA class I/II, but not always at the same time as the C4d-positive biopsy. CONCLUSIONS: In the first month posttransplantation, prospective monitoring of anti-HLA antibodies may be useful. The high sensitivity allows the identification of patients at risk, affording an earlier diagnosis of antibody-mediated rejection. After the first month, the test can be used to evaluate allograft dysfunction episodes, since positivity is highly suggestive of an antibody-mediated process.
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Background: Heart transplant rejection originates slow and fragmented conduction. Signal-averaged ECG (SAECG) is a stratification method in the risk of rejection. Objective: To develop a risk score for rejection, using SAECG variables. Methods: We studied 28 transplant patients. First, we divided the sample into two groups based on the occurrence of acute rejection (5 with rejection and 23 without). In a second phase, we divided the sample considering the existence or not of rejection in at least one biopsy performed on the follow-up period (rejection pm1: 18 with rejection and 10 without). Results: On conventional ECG, the presence of fibrosis was the only criterion associated with acute rejection (OR = 19; 95% CI = 1.65-218.47; p = 0.02). Considering the rejection pm1, an association was found with the SAECG variables, mainly with RMS40 (OR = 0.97; 95% CI = 0.87-0.99; p = 0.03) and LAS40 (OR = 1.06; 95% IC = 1.01-1.11; p = 0.03). We formulated a risk score including those variables, and evaluated its discriminative performance in our sample. The presence of fibrosis with increasing of LAS40 and decreasing of RMS40 showed a good ability to distinguish between patients with and without rejection (AUC = 0.82; p < 0.01), assuming a cutoff point of sensitivity = 83.3% and specificity = 60%. Conclusion: The SAECG distinguished between patients with and without rejection. The usefulness of the proposed risk score must be demonstrated in larger follow-up studies.
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rejection can lead to loss of function. Histological reading of endomyocardial biopsy remains the "gold standard" for guiding immunosuppression, despite its methodological limitations (sampling error and interobserver variability). The measurement of the T2 relaxation time has been suggested for detection of allograft rejection, on the pathophysiological basis that the T2 relaxation time prolongs with local edema resulting from acute allograft rejection. Using breath-held cardiac magnetic resonance T2 mapping at 1.5 T, Usman et al. (CircCardiovascImaging2012) detected moderate allograft rejection (grade 2R, ISHLT 2004). With modern immunosuppression grade 2R rejection has become a rare event, but the need remains for a technique that permits the discrimination of absent (grade 0R) and mild rejection (grade 1R). We therefore investigated whether an increase of magnetic field strength to 3T and the use of real-time navigator-gated respiration compensation allow for an increase in the sensitivity of T2 relaxation time detection that is necessary to achieve this discrimination. Methods: Eighteen patients received EMB (Tan et al., ArchPatholLabMed2007) and cardiac T2 mapping on the same day. Reading of T2 maps was blinded to the histological results. For final analysis, 3 cases with known 2R rejection at the time of T2 mapping were added, yielding 21 T2 mapping sessions. A respiration-navigator-gated radial gradient-recalled-echo pulse sequence (resolution 1.17 mm2, matrix 2562, trigger time 3 heartbeats, T2 preparation duration TET2 Prep = 60/30/0 ms) was applied to obtain 3 short-axis T2 maps (van Heeswijk et al., JACCCardiovascImaging2012), which were segmented according to AHA guidelines (Cerqueira et al, Circulation2001). The highest segmental T2 values were grouped according to histological rejection grade and differences were analyzed by Student's t-test, except for the non-blinded cases with 2R rejection. The degree of discrimination was determined using the Spearman's ranked correlation test. Results: The high-quality T2 maps allowed for visual differentiation of the rejection degrees (Figure 1), and the correlation of T2 mapping with the histological grade of acute cellular rejection was significant (Spearman's r = 0.56, p = 0.007). The 0R (n = 15) and 1R (n = 3) degrees demonstrated significantly different T2 values (46.9 ± 5.0 and 54.3 ± 3.0 ms, p = 0.02, Figure 2). Cases with 2R rejection showed clear T2 elevation (T2 = 60.3 ± 16.2 ms). Conclusions: This pilot study demonstrates that non-invasive free-breathing cardiac T2 mapping at 3T discriminates between no and mild cardiac allograft rejection. Confirmation of these encouraging results in a larger cohort should consider a study able to show equivalency or superiority of T2 mapping.
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Since the late 1990’s, a group of moral doctrines called prioritarianism has received a lot of interest from many moral philosophers. Many contemporary moral philosophers are attracted to prioritarianism to such an extent that they can be called prioritarians. In this book, however, I reject prioritarianism, including not only “pure” prioritarianism but also hybrid prioritarian views which mix one or more non-prioritarian elements with prioritarianism. This book largely revolves around certain problems and complications of prioritarianism and its particular forms. Those problems and complications are connected to risk, impartiality, the arbitrariness of prioritarian weightings and possible future individuals. On the one hand, I challenge prioritarianism through targeted objections to various specific forms of prioritarianism. All those targeted objections are connected to risk or possible future individuals. It seems to me that together they give good grounds for believing that prioritarianism is not the way to go. On the other hand, I challenge prioritarianism by pointing out and discussing certain general problems of prioritarianism. Those general problems are connected to impartiality and the arbitrariness of prioritarian weightings. They may give additional grounds for believing that all prioritarian views should be rejected. Prioritarianism can be seen as a type of weighted utilitarianism and thus as an extension of utilitarianism. Utilitarianism is morally ultimately concerned, and morally ultimately concerned only, with some kind of maximization of utility or expected utility. Prioritarianism, on the other hand, is morally ultimately concerned, and morally ultimately concerned only, with some kind of maximization of priority-weighted utility, expected priority-weighted utility or priority-weighted expected utility. Thus prioritarianism, unlike utilitarianism, is a distribution-sensitive moral view. Besides rejecting prioritarianism, I reject also various other distribution-sensitive moral views in this book. However, I do not reject distribution-sensitivity in morality, as I end up endorsing a type of distribution-sensitive hybrid utilitarianism which mixes non-utilitarian elements with utilitarianism.
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Prompt and accurate detection of rejection prior to pathological changes after organ transplantation is vital for monitoring rejections. Although biopsy remains the current gold standard for rejection diagnosis, it is an invasive method and cannot be repeated daily. Thus, noninvasive monitoring methods are needed. In this study, by introducing an IL-2 neutralizing monoclonal antibody (IL-2 N-mAb) and immunosuppressants into the culture with the presence of specific stimulators and activated lymphocytes, an activated lymphocyte-specific assay (ALSA) system was established to detect the specific activated lymphocytes. This assay demonstrated that the suppression in the ALSA test was closely related to the existence of specific activated lymphocytes. The ALSA test was applied to 47 heart graft recipients and the proliferation of activated lymphocytes from all rejection recipients proven by endomyocardial biopsies was found to be inhibited by spleen cells from the corresponding donors, suggesting that this suppression could reflect the existence of activated lymphocytes against donor antigens, and thus the rejection of a heart graft. The sensitivity of the ALSA test in these 47 heart graft recipients was 100%; however, the specificity was only 37.5%. It was also demonstrated that IL-2 N-mAb was indispensible, and the proper culture time courses and concentrations of stimulators were essential for the ALSA test. This preliminary study with 47 grafts revealed that the ALSA test was a promising noninvasive tool, which could be used in vitro to assist with the diagnosis of rejection post-heart transplantation.
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BACKGROUND.: Urine is a potentially rich source of biomarkers for monitoring kidney dysfunction. In this study, we have investigated the potential of soluble human leukocyte antigen (sHLA)-DR in the urine for noninvasive monitoring of renal transplant patients. METHODS.: Urinary soluble HLA-DR levels were measured by sandwich enzyme-linked immunosorbent assay in 103 patients with renal diseases or after renal transplantation. sHLA-DR in urine was characterized by Western blotting and mass spectrometry. RESULTS.: Acute graft rejection was associated with a significantly elevated level of urinary sHLA-DR (P<0.0001), compared with recipients with stable graft function or healthy individuals. A receiver operating characteristic curve analysis showed the area under the curve to be 0.88 (P<0.001). At a selected threshold, the sensitivity was 80% and specificity was 98% for detection of acute renal transplant rejection. sHLA-DR was not exosomally associated and was of lower molecular weight compared with the HLA-DR expressed as heterodimer on the plasma membrane of antigen-presenting cells. CONCLUSIONS.: sHLA-DR excreted into urine is a promising indicator of renal transplant rejection.
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We study the sensitivity of multi ton-scale time projection chambers using a liquid xenon target, e.g., the proposed DARWIN instrument, to spin-independent and spin-dependent WIMP-nucleon scattering interactions. Taking into account realistic backgrounds from the detector itself as well as from neutrinos, we examine the impact of exposure, energy threshold, background rejection efficiency and energy resolution on the dark matter sensitivity. With an exposure of 200 t x y and assuming detector parameters which have been already demonstrated experimentally, spin-independent cross sections as low as 2.5×10−49 cm2 can be probed for WIMP masses around 40 GeV/c2. Additional improvements in terms of background rejection and exposure will further increase the sensitivity, while the ultimate WIMP science reach will be limited by neutrinos scattering coherently off the xenon nuclei.
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To determine if magnesium deficiency aggravates the effects of a high-fat diet in growing rats in terms of obesity, lipid profile and insulin resistance. The study population comprised 48 newly weaned male Wistar Hannover rats distributed into four groups according to diet, namely, control group (CT; n = 8), control diet provided ad libitum; pair-feeding control group (PF; n = 16), control diet but in the same controlled amount as animals that received high-fat diets; high-fat diet group (HF; n = 12), and magnesium-deficient high-fat diet group (HFMg(-); n = 12). The parameters investigated were adiposity index, lipid profile, magnesium status, insulin sensitivity and the phosphorylation of proteins involved in the insulin-signaling pathway, i.e. insulin receptor β-subunit, insulin receptor substrate 1 and protein kinase B. The HF and HFMg(-) groups were similar regarding gain in body mass, adiposity index and lipid profile, but were significantly different from the PF group. The HFMg(-) group exhibited alterations in magnesium homeostasis as revealed by the reduction in urinary and bone concentrations of the mineral. No inter-group differences were observed regarding glucose homeostasis. Protein phosphorylation in the insulin-signaling pathway was significantly reduced in the high-fat groups compared with the control groups, demonstrating that the intake of fat-rich diets increased insulin resistance, a syndrome that was aggravated by magnesium deficiency. Under the experimental conditions tested, the intake of a magnesium-deficient high-fat diet led to alterations in the insulin-signaling pathway and, consequently, increased insulin resistance.
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Herpesvirus reactivation is common after liver transplantation. Analyze the presence of cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6) DNA in liver donor biopsies, seeking to better understand issues involving human donor leukocyte antigens (HLA)-A, B and DR, as well as correlations with acute cellular rejection. Fifty-nine liver transplantation patients were investigated for the presence of HCMV and HHV-6 DNA in liver donor biopsies, using the Nested-PCR technique. The clinical donor information and HLA matches were obtained from the São Paulo State Transplant System. The recipients' records regarding acute cellular rejection were studied. Seven (11.8%) biopsies were positive for HCMV DNA and 29 (49%) were positive for HHV-6 DNA. In 14 donors with HLA-DR 15 nine had HHV-6 DNA positive liver biopsy with a tendency for significant association (p=0.09), 22 recipients developed acute cellular rejection and 9/22 were positive for HLA-DR 15 (p=0.03; χ(2)=4.51), which was statistically significant in univariate analysis and showed a tendency after multivariate analysis (p=0.08). HHV-6 DNA was prevalent in liver donors studied as well as HLA-DR 15. These findings suggest that patients with HLA-DR 15 in liver donor biopsies develop more rejection after liver transplantation.