Background Advantages of the arteriovenous fistula (AVF), including long patency and few complications, were ascertained more than 2 decades ago and may not apply to the contemporary dialysis ...population. Study Design Systematic review and meta-analysis. Estimates were pooled using a random-effects model and sources of heterogeneity were explored using metaregression. Setting & Population Patients treated with long-term hemodialysis using an AVF. Selection Criteria for Studies English-language studies indexed in MEDLINE between 2000 and 2012 using prospectively collected data on 100 or more AVFs. Predictor Age, AVF location, and study location. Outcomes Outcomes of interest were primary AVF failure and primary and secondary patency at 1 and 2 years. Results 7,011 citations were screened and 46 articles met eligibility criteria (62 unique cohorts; n = 12,383). The rate of primary failure was 23% (95% CI, 18%-28%; 37 cohorts; 7,393 AVFs). When primary failures were included, the primary patency rate was 60% (95% CI, 56%-64%; 13 studies; 21 cohorts; 4,111 AVFs) at 1 year and 51% (95% CI, 44%-58%; 7 studies; 12 cohorts; 2,694 AVFs) at 2 years. The secondary patency rate was 71% (95% CI, 64%-78%; 10 studies; 11 cohorts; 3,558 AVFs) at 1 year and 64% (95% CI, 56%-73%; 6 studies; 11 cohorts; 1,939 AVFs) at 2 years. In metaregression, there was a significant decrease in primary patency rate in studies that started recruitment in more recent years. Limitations Low quality of studies, variable clinical settings, and variable definitions of primary AVF failure. Conclusions In recent years, AVFs had a high rate of primary failure and low to moderate primary and secondary patency rates. Consideration of these outcomes is required when choosing a patient's preferred access type.
Image segmentation of retinal blood vessels is a process that can help to predict and diagnose cardiovascular related diseases, such as hypertension and diabetes, which are known to affect the ...retinal blood vessels' appearance. This work proposes an unsupervised method for the segmentation of retinal vessels images using a combined matched filter, Frangi's filter and Gabor Wavelet filter to enhance the images. The combination of these three filters in order to improve the segmentation is the main motivation of this work. We investigate two approaches to perform the filter combination: weighted mean and median ranking. Segmentation methods are tested after the vessel enhancement. Enhanced images with median ranking are segmented using a simple threshold criterion. Two segmentation procedures are applied when considering enhanced retinal images using the weighted mean approach. The first method is based on deformable models and the second uses fuzzy C-means for the image segmentation. The procedure is evaluated using two public image databases, Drive and Stare. The experimental results demonstrate that the proposed methods perform well for vessel segmentation in comparison with state-of-the-art methods.
Clinical inertia Phillips, L S; Branch, W T; Cook, C B ...
Annals of internal medicine,
11/2001, Letnik:
135, Številka:
9
Journal Article
Recenzirano
Medicine has traditionally focused on relieving patient symptoms. However, in developed countries, maintaining good health increasingly involves management of such problems as hypertension, ...dyslipidemia, and diabetes, which often have no symptoms. Moreover, abnormal blood pressure, lipid, and glucose values are generally sufficient to warrant treatment without further diagnostic maneuvers. Limitations in managing such problems are often due to clinical inertia-failure of health care providers to initiate or intensify therapy when indicated. Clinical inertia is due to at least three problems: overestimation of care provided; use of "soft" reasons to avoid intensification of therapy; and lack of education, training, and practice organization aimed at achieving therapeutic goals. Strategies to overcome clinical inertia must focus on medical students, residents, and practicing physicians. Revised education programs should lead to assimilation of three concepts: the benefits of treating to therapeutic targets, the practical complexity of treating to target for different disorders, and the need to structure routine practice to facilitate effective management of disorders for which resolution of patient symptoms is not sufficient to guide care. Physicians will need to build into their practice a system of reminders and performance feedback to ensure necessary care.
MicroRNA (miRNA)-deficient helper T cells exhibit abnormal IFN-γ production and decreased proliferation. However, the contributions of individual miRNAs to this phenotype remain poorly understood. We ...conducted a screen for miRNA function in primary T cells and identified individual miRNAs that rescue the defects associated with miRNA deficiency. Multiple members of the miR-17 and miR-92 families enhanced miRNA-deficient T cell proliferation whereas miR-29 largely corrected their aberrant interferon-γ (IFN-γ) expression. Repression of IFN-γ production by miR-29 involved direct targeting of both T-bet and Eomes, two transcription factors known to induce IFN-γ production. Although not usually expressed at functionally relevant amounts in helper T cells, Eomes was abundant in miRNA-deficient cells and was upregulated after miR-29 inhibition in wild-type cells. These results demonstrate that miR-29 regulates helper T cell differentiation by repressing multiple target genes, including at least two that are independently capable of inducing the T helper 1 (Th1) cell gene expression program.
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► miRNA -deficient T cells exhibit cell-intrinsic defects in IFN-γ signaling ► Individual miRNAs independently rescue specific defects of miRNA-deficient T cells ► miR-29 negatively regulates IFN-γ production in helper T cells ► IFN-γ repression by miR-29 involves regulation of both T-bet and Eomes
People with psychoses often report fixed, delusional beliefs that are sustained even in the presence of unequivocal contrary evidence. Such delusional beliefs are the result of integrating new and ...old evidence inappropriately in forming a cognitive model. We propose and test a cognitive model of belief formation using experimental data from an interactive 'Rock Paper Scissors' (RPS) game.
Participants (33 controls and 27 people with schizophrenia) played a competitive, time-pressured interactive two-player game (RPS). Participants' behavior was modeled by a generative computational model using leaky integrator and temporal difference methods. This model describes how new and old evidence is integrated to form a playing strategy to beat the opponent and to provide a mechanism for reporting confidence in one's playing strategy to win against the opponent.
People with schizophrenia fail to appropriately model their opponent's play despite consistent (rather than random) patterns that can be exploited in the simulated opponent's play. This is manifest as a failure to weigh existing evidence appropriately against new evidence. Furthermore, participants with schizophrenia show a 'jumping to conclusions' (JTC) bias, reporting successful discovery of a winning strategy with insufficient evidence.
The model presented suggests two tentative mechanisms in delusional belief formation: (i) one for modeling patterns in other's behavior, where people with schizophrenia fail to use old evidence appropriately, and (ii) a metacognitive mechanism for 'confidence' in such beliefs, where people with schizophrenia overweight recent reward history in deciding on the value of beliefs about the opponent.
Tumors develop through successive stages characterized by changes in gene expression and protein function. Gene expression profiling of pancreatic islet tumors in a mouse model of cancer revealed ...upregulation of cathepsin cysteine proteases. Cathepsin activity was assessed using chemical probes allowing biochemical and in vivo imaging, revealing increased activity associated with the angiogenic vasculature and invasive fronts of carcinomas, and differential expression in immune, endothelial, and cancer cells. A broad-spectrum cysteine cathepsin inhibitor was used to pharmacologically knock out cathepsin function at different stages of tumorigenesis, impairing angiogenic switching in progenitor lesions, as well as tumor growth, vascularity, and invasiveness. Cysteine cathepsins are also upregulated during HPV16-induced cervical carcinogenesis, further encouraging consideration of this protease family as a therapeutic target in human cancers.
Striking cardiovascular health disparities exist among African-Americans in Minnesota compared to Whites; however, community-based interventions to address cardiovascular disease risk are lacking. ...This study explored participant perceptions of a culturally tailored, cardiovascular disease prevention program developed using a community-based participatory research process. Research participation perceptions, program benefits, and program satisfaction/acceptability were analyzed using a mixed-methods approach. Overall, acceptability was high. Findings highlight the favorable inclusion of African-Americans (research perception), knowledge gained about healthy lifestyle practices (benefits), and quality of the curriculum/speakers (satisfaction). Community-based participatory research may be useful in fostering the acceptability of behavior change interventions among marginalized African-American communities.
A major unanswered question is what distinguishes the majority of activated CD8 T cells that die after an acute viral infection from the small fraction (5-10%) that survive to become long-lived ...memory cells. In this study we show that increased expression of the interleukin 7 receptor alpha-chain (IL-7Ralpha) identifies the effector CD8 T cells that will differentiate into memory cells. IL-7R(hi) effector cells contained increased amounts of antiapoptotic molecules, and adoptive transfer of IL-7R(hi) and IL-7R(lo) effector cells showed that IL-7R(hi) cells preferentially gave rise to memory cells that could persist and confer protective immunity. Thus, selective expression of IL-7R identifies memory cell precursors, and this marker may be useful in predicting the number of memory T cells generated after infection or immunization.
Loss of imprinting at IGF2, generally through an H19-independent mechanism, is associated with a large percentage of patients with the overgrowth and cancer predisposition condition ...Beckwith-Wiedemann syndrome (BWS). Imprinting control elements are proposed to exist within the KvLQT1 locus, because multiple BWS-associated chromosome rearrangements disrupt this gene. We have identified an evolutionarily conserved, maternally methylated CpG island (KvDMR1) in an intron of the KvLQT1 gene. Among 12 cases of BWS with normal H19 methylation, 5 showed demethylation of KvDMR1 in fibroblast or lymphocyte DNA; whereas, in 4 cases of BWS with H19 hypermethylation, methylation at KvDMR1 was normal. Thus, inactivation of H19 and hypomethylation at KvDMR1 (or an associated phenomenon) represent distinct epigenetic anomalies associated with biallelic expression of IGF2. Reverse transcription-PCR analysis of the human and syntenic mouse loci identified the presence of a KvDMR1-associated RNA transcribed exclusively from the paternal allele and in the opposite orientation with respect to the maternally expressed KvLQT1 gene. We propose that KvDMR1 and/or its associated antisense RNA (KvLQT1-AS) represents an additional imprinting control element or center in the human 11p15.5 and mouse distal 7 imprinted domains.
Cytokines, particularly those of the common gamma chain receptor family, provide extrinsic signals that regulate naive CD4 cell survival. Whether these cytokines are required for the maintenance of ...memory CD4 cells has not been rigorously assessed. In this paper, we examined the contribution of interleukin (IL) 7, a constitutively produced common gamma chain receptor cytokine, to the survival of resting T cell receptor transgenic memory CD4 cells that were generated in vivo. IL-7 mediated the survival and up-regulation of Bcl-2 by resting memory CD4 cells in vitro in the absence of proliferation. Memory CD4 cells persisted for extended periods upon adoptive transfer into intact or lymphopenic recipients, but not in IL-7- mice or in recipients that were rendered deficient in IL-7 by antibody blocking. Both central (CD62L+) and effector (CD62L-) memory phenotype CD4 cells required IL-7 for survival and, in vivo, memory cells were comparable to naive CD4 cells in this regard. Although the generation of primary effector cells from naive CD4 cells and their dissemination to nonlymphoid tissues were not affected by IL-7 deficiency, memory cells failed to subsequently develop in either the lymphoid or nonlymphoid compartments. The results demonstrate that IL-7 can have previously unrecognized roles in the maintenance of memory in the CD4 cell population and in the survival of CD4 cells with a capacity to become memory cells.
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