TRIM21 is an IgG receptor that is structurally, thermodynamically, and kinetically conserved

The newly identified tripartite motif (TRIM) family of proteins mediate innate immunity and other critical cellular functions. Here we show that TRIM21, which mediates the autoimmune diseases rheumatoid arthritis, systemic lupus erythematosus, and Sjögren''s syndrome, is a previously undescribed IgG receptor with a binding mechanism unlike known mammalian Fcγ receptors. TRIM21 simultaneously targets conserved hot-spot residues on both Ig domains of the Fc fragment using a PRYSPRY domain with a preformed multisite interface. The binding sites on both TRIM21 and Fc are highly conserved to the extent that the proteins are functionally interchangeable through murine, canine, primate, and human species. Pre-steady-state analysis exposes mechanistic conservation at the level of individual residues, which make the same energetic and kinetic contributions to binding despite varying in sequence. Together, our results reveal that TRIM21 is a previously undescribed type of IgG receptor based on a non-Ig scaffold whose interaction at the fundamental level—structural, thermodynamic, and kinetic—is evolutionarily conserved.     

Effects of inhibiting astrocytes and BET/BRD4 chromatin reader on spatial memory and synaptic proteins in rats with Alzheimer’s disease

Metabolic Brain Disease - Communication between astrocytes and neurons has a profound effect on the pathophysiology of Alzheimer’s disease (AD). Astrocytes regulate homeostasis and increase...     

Automatic Computation of Left Ventricular Volume Changes Over a Cardiac Cycle from Echocardiography Images by Nonlinear Dimensionality Reduction

Curve of left ventricular (LV) volume changes throughout the cardiac cycle is a fundamental parameter for clinical evaluation of various cardiovascular diseases. Currently, this evaluation is often performed manually which is tedious and time consuming and suffers from significant interobserver and intraobserver variability. This paper introduces a new automatic method, based on nonlinear dimensionality reduction (NLDR) for extracting the curve of the LV volume changes over a cardiac cycle from two-dimensional (2-D) echocardiography images. Isometric feature mapping (Isomap) is one of the most popular NLDR algorithms. In this study, a modified version of Isomap algorithm, where image to image distance metric is computed using nonrigid registration, is applied on 2-D echocardiography images of one cycle of heart. Using this approach, the nonlinear information of these images is embedded in a 2-D manifold and each image is characterized by a symbol on the constructed manifold. This new representation visualizes the relationship between these images based on LV volume changes and allows extracting the curve of the LV volume changes automatically. Our method in comparison to the traditional segmentation algorithms does not need any LV myocardial segmentation and tracking, particularly difficult in the echocardiography images. Moreover, a large data set under various diseases for training is not required. The results obtained by our method are quantitatively evaluated to those obtained manually by the highly experienced echocardiographer on ten healthy volunteers and six patients which depict the usefulness of the presented method.     

Evaluation of Educational Environment for Medical Students of a Tertiary Pediatric Hospital in Tehran,Using DREEM Questionnaire

Background:

Tertiary pediatric hospitals usually provide excellent clinical services, but such centers have a lot to do for educational perfection.

Objectives:

This study was performed to address under-graduate educational deficits and find feasible solutions.

Patients and Methods:

This cross-sectional study was done in a target population of 77 sixth year undergraduate medical students (response rate = 78%) who spent their 3-month pediatric rotation in the Children’s Medical Center, the Pediatrics Center of Excellence in Tehran, Iran. The Dundee ready educational environment measure (DREEM) instrument was used for assessing educational environment of this subspecialized pediatric hospital.

Results:

Among 60 students who answered the questionnaires, 24 were male (40%). Participants’ age ranged from 23 to 24 years. The mean total score was 95.8 (48%). Comparison of scores based on students’ knowledge showed no significant difference. Problematic areas were learning, academic self-perception, and social self-perception.

Conclusions:

Having an accurate schedule to train general practitioner, using new teaching methods, and providing a non-stressful atmosphere were suggested solutions.     

Cu-MOF: an efficient heterogeneous catalyst for the synthesis of symmetric anhydrides via the C–H bond activation of aldehydes

In this paper, an efficient and straightforward synthetic approach for the preparation of a number of symmetric carboxylic anhydrides was reported using Cu₂(BDC)₂(DABCO) as an efficient heterogeneous catalyst via the C–H bond activation of aldehydes with excellent yields and simple work up. This C–H bond activation reaction appears simple and convenient, has a wide substrate scope and makes use of cheap, abundant, and easily available reagents. The Cu-MOF catalyst was recycled and reused four times without any loss of catalytic activity.

In this paper, an efficient synthetic method for the preparation of symmetric carboxylic anhydrides was reported using Cu₂(BDC)₂(DABCO) as an efficient heterogeneous catalyst via the C–H bond activation of aldehydes with good yields and simple work up.