• McKee Bentzen opublikował 1 rok, 8 miesięcy temu

    This homogeneity test is based upon the deviation between overall treatment effect and subgroup-specific effects on the odds ratio scale and is compared with an equivalence test based on the ratio of both subgroup-specific effects. Performance of these consistency tests is assessed in a simulation study. In addition, the consistency tests are outlined for the relative risk regression. The proposed homogeneity test reaches sufficient power in realistic scenarios with small interactions. As expected, power decreases for unbalanced subgroups, lower sample sizes, and narrower margins. Severe interactions are covered by the null hypothesis and are more likely to be rejected the stronger they are.DCM is the leading cause of death in Duchenne patients. LVADs are considered as therapeutic options as DT in advanced HF. The aim of our study was to evaluate LV remodeling of Duchenne after LVADs and chronic therapy. Demographic and echocardiographic data of 8 Duchenne patients implanted with LVADs were reviewed and analyzed. All measures were collected before LVAD implantation, after 1 month and 1 year. All patients were affected by end-stage DCM, and mean age at implantation was 16.9 ± 2.9 years. Patients were treated with maximal medical therapy. One-year post-implantation HR decreased from a mean of 110 ± 19 bpm to 82 ± 2 bpm (P = .002), and a significant decrease in LV volumes and diameters LVEDD P = .03, LVESD P = .02, EDV P = .01, and ESV P = .02) was noticed together with a significant increase in EF (P = .0036). However, RWT did not change over time, showing an eccentric remodeling pattern pre- and post-LVADs. Our data showed that cardiac atrophy is persistent in Duchenne cardiomyopathy despite the improvement of LV function secondary to a significant ventricular unloading due to LVADs coupled with chronic therapy.When interpreting the relative effects from a network meta-analysis (NMA), researchers are usually aware of the potential limitations that may render the results for some comparisons less useful or meaningless. In the presence of sufficient and appropriate data, some of these limitations (eg, risk of bias, small-study effects, publication bias) can be taken into account in the statistical analysis. Very often, though, the necessary data for applying these methods are missing and data limitations cannot be formally integrated into ranking. In addition, there are other important characteristics of the treatment comparisons that cannot be addressed within a statistical model but only through qualitative judgments; for example, the relevance of data to the research question, the plausibility of the assumptions, and so on. Here, we propose a new measure for treatment ranking called the Probability of Selecting a Treatment to Recommend (POST-R). We suggest that the order of treatments should represent the process of considering treatments for selection in clinical practice and we assign to each treatment a probability of being selected. This process can be considered as a Markov chain model that allows the end-users of NMA to select the most appropriate treatments based not only on the NMA results but also to information external to the NMA. In this way, we obtain rankings that can inform decision-making more efficiently as they represent not only the relative effects but also their potential limitations. We illustrate our approach using a NMA comparing treatments for chronic plaque psoriasis and we provide the Stata commands.In many health-related programs biochemistry and molecular biology are core subjects, but these subjects are often not the students main focus. This challenges educators to develop curriculum that demonstrates the relevance of biochemistry and molecular biology and engages these students. This conference session discussed the value of biochemistry and molecular biology education in the health sciences and the methodologies which can be implemented.Quinone methide (QM) chemistry is widely applied including in enzyme inhibitors. Typically, enzyme-mediated bond breaking releases a phenol product that rearranges into an electrophilic QM that in turn covalently modifies protein side chains. However, the factors that govern the reactivity of QM-based inhibitors and their mode of inhibition have not been systematically explored. Foremost, enzyme inactivation might occur in cis, whereby a QM molecule inactivates the very same enzyme molecule that released it, or by trans if the released QMs diffuse away and inactivate other enzyme molecules. We examined QM-based inhibitors for enzymes exhibiting phosphoester hydrolase activity. We tested different phenolic substituents and benzylic leaving groups, thereby modulating the rates of enzymatic hydrolysis, phenolate-to-QM rearrangement, and the electrophilicity of the resulting QM. By developing assays that distinguish between cis and trans inhibition, we have identified certain combinations of leaving groups and phenyl substituents that lead to inhibition in the cis mode, while other combinations gave trans inhibition. Our results suggest that cis-acting QM-based substrates could be used as activity-based probes to identify various phospho- and phosphono-ester hydrolases, and potentially other hydrolases.The Cox proportional hazards model is typically used to analyze time-to-event data. If the event of interest is rare and covariates are difficult or expensive to collect, the nested case-control (NCC) design provides consistent estimates at reduced costs with minimal impact on precision if the model is specified correctly. If our scientific goal is to conduct inference regarding an association of interest, it is essential that we specify the model a priori to avoid multiple testing bias. We cannot, however, be certain that all assumptions will be satisfied so it is important to consider robustness of the NCC design under model misspecification. In this manuscript, we show that in finite sample settings where the functional form of a covariate of interest is misspecified, the estimates resulting from the partial likelihood estimator under the NCC design depend on the number of controls sampled at each event time. To account for this dependency, we propose an estimator that recovers the results obtained using using the full cohort, where full covariate information is available for all study participants. We present the utility of our estimator using simulation studies and show the theoretical properties. We end by applying our estimator to motivating data from the Alzheimer’s Disease Neuroimaging Initiative.The accelerated failure time (AFT) model has been suggested as an alternative to the Cox proportional hazards model. However, a parametric AFT model requires the specification of an appropriate distribution for the event time, which is often difficult to identify in real-life studies and may limit applications. A semiparametric AFT model was developed by Komárek et al based on smoothed error distribution that does not require such specification. In this article, we develop a spline-based AFT model that also does not require specification of the parametric family of event time distribution. The baseline hazard function is modeled by regression B-splines, allowing for the estimation of a variety of smooth and flexible shapes. In comprehensive simulations, we validate the performance of our approach and compare with the results from parametric AFT models and the approach of Komárek. Both the proposed spline-based AFT model and the approach of Komárek provided unbiased estimates of covariate effects and survival curves for a variety of scenarios in which the event time followed different distributions, including both simple and complex cases. Spline-based estimates of the baseline hazard showed also a satisfactory numerical stability. As expected, the baseline hazard and survival probabilities estimated by the misspecified parametric AFT models deviated from the truth. We illustrated the application of the proposed model in a study of colon cancer.

     We investigate the role of preoperative PET parameters to determine risk classes and prognosis of endometrial cancer (EC).

     We enrolled 81 patients with EC who underwent preoperative F-18 FDG PET/CT. PET parameters (SUV

    , SUV

    , MTV, TLG), grade, histology and size of the primary tumor, stage of the disease, the degree of myometrial invasion (MI), and the presence of lymphovascular invasion (LVI), cervical invasion (CI), distant metastasis (DM) and lymph node metastasis (LNM) were recorded. The relationship between PET parameters, clinicopathological risk factors and overall survival (OS) was evaluated.

     The present study included 81 patients with EC (mean age 60). Of the total sample, 21 patients were considered low risk (endometrioid histology, stage 1A, grade 1 or 2, tumor diameter < 4 cm, and LVI negative) and 60 were deemed high risk. All of the PET parameters were higher in the presence of a high-risk state, greater tumor size, deep MI, LVI and stage 1B-4B. MTV and TLG values were higher in the patients with non-endometrioid histology, CI, grade 3 and LNM. The optimum cut-off levels for differentiating between the high and low risk patients were 11.1 for SUV

    (AUC = 0.757), 6 for SUV

    (AUC = 0.750), 6.6 for MTV(AUC = 0.838) and 56.2 for TLG(AUC = 0.835). MTV and TLG values were found as independent prognostic factors for OS, whereas SUV

    and SUV

    values were not predictive.

     The PET parameters are useful in noninvasively differentiating between risk groups of EC. Furthermore, volumetric PET parameters can be predictive for OS of EC.

     The PET parameters are useful in noninvasively differentiating between risk groups of EC. Furthermore, volumetric PET parameters can be predictive for OS of EC.

     Since 2017, medical students at the University of Bergen were taught PET/CT „hands-on” by viewing PET/CT cases in native format on diagnostic workstations in the hospital. Due to the COVID-19 pandemic, students were barred access. This prompted us to launch and evaluate a new freeware PET/CT viewing system hosted in the university network.

     We asked our students to install the multiplatform Fiji viewer with Beth Israel PET/CT plugin (http//petctviewer.org) on their personal computers and connect to a central image database in the university network based on the public domain orthanc server (https//orthanc-server.com). At the end of course, we conducted an anonymous student survey.

     The new system was online within eight days, including regulatory approval. All 76 students (100 %) in the fifth year completed their course work, reading five anonymized PET/CT cases as planned. 41 (53 %) students answered the survey. Fiji was challenging to install with a mean score of 1.8 on a 5-point Likert scale (5 = eat regardless of time or location.Adenomyosis, characterized by the presence of endometrial glands and stroma within the myometrium, can have a substantial impact on the quality of women’s lives. Despite this, the epidemiologic research on this condition lags considerably behind that of other noncancerous reproductive health conditions. The lack of progress and knowledge is due in part to the challenges in designing valid epidemiologic studies, since the diagnosis of adenomyosis historically has been limited to the examination of uterine specimens from hysterectomy. This review describes the available data on the frequency of this condition and the epidemiologic investigation thus far into the risk factors for disease-highlighting the methodologic and inference challenges primarily around study sample selection. We conclude with providing recommendations for approaches to future epidemiologic study that capitalize on the advancements in imaging technology to detect adenomyosis and provide a fuller picture of the occurrence and risk factors for disease.

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