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1.
Patrick W. Keeley Mikayla C. Lebo Jordan D. Vieler Jason J. Kim Ace J. St. John Benjamin E. Reese 《The Journal of neuroscience》2021,41(1):103
Amacrine cells of the retina are conspicuously variable in their morphologies, their population demographics, and their ensuing functions. Vesicular glutamate transporter 3 (VGluT3) amacrine cells are a recently characterized type of amacrine cell exhibiting local dendritic autonomy. The present analysis has examined three features of this VGluT3 population, including their density, local distribution, and dendritic spread, to discern the extent to which these are interrelated, using male and female mice. We first demonstrate that Bax-mediated cell death transforms the mosaic of VGluT3 cells from a random distribution into a regular mosaic. We subsequently examine the relationship between cell density and mosaic regularity across recombinant inbred strains of mice, finding that, although both traits vary across the strains, they exhibit minimal covariation. Other genetic determinants must therefore contribute independently to final cell number and to mosaic order. Using a conditional KO approach, we further demonstrate that Bax acts via the bipolar cell population, rather than cell-intrinsically, to control VGluT3 cell number. Finally, we consider the relationship between the dendritic arbors of single VGluT3 cells and the distribution of their homotypic neighbors. Dendritic field area was found to be independent of Voronoi domain area, while dendritic coverage of single cells was not conserved, simply increasing with the size of the dendritic field. Bax-KO retinas exhibited a threefold increase in dendritic coverage. Each cell, however, contributed less dendrites at each depth within the plexus, intermingling their processes with those of neighboring cells to approximate a constant volumetric density, yielding a uniformity in process coverage across the population.SIGNIFICANCE STATEMENT Different types of retinal neuron spread their processes across the surface of the retina to achieve a degree of dendritic coverage that is characteristic of each type. Many of these types achieve a constant coverage by varying their dendritic field area inversely with the local density of like-type neighbors. Here we report a population of retinal amacrine cells that do not develop dendritic arbors in relation to the spatial positioning of such homotypic neighbors; rather, this cell type modulates the extent of its dendritic branching when faced with a variable number of overlapping dendritic fields to approximate a uniformity in dendritic density across the retina. 相似文献
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Thomas Ruffing Tilmann Rückauer Frederic Bludau Alexander Hofmann Markus Muhm Arnold J Suda 《Injury》2019,50(2):607-612
Introduction
Compression fractures of the cuboid bone in children and adolescents are rare. Fracture morphology, associated lesions, treatment options and long-term outcomes of this very rare injury are published in a few case reports. This study with review of the literature aims to support the understanding of fracture pattern and optimize pathways of decision making.Material and Methods
A retrospective two-center study was performed in a patient cohort treated between 2001 and 2016. All patients aged less than 18 years who sustained a cuboid fracture were included. Age, gender, mechanism of injury, fracture morphology, amount of displacement, associated injuries, and therapy were analyzed. In the follow-up (FU), the AOFAS Midfoot Scale was investigated.Results
Fractures of the cuboid bone were diagnosed in 7 boys and 9 girls. The mean age of the patients was 10 years (range: 2.2–16.1 years). According to the classification of Fenton we detected 11 (69%) type 2, 2 (12%) type 3 and 3 (19%) type 5b fractures. Other fracture types according to Fenton were not observed. All children under 10 years sustained a type 2 fracture. Open reduction and internal fixation was performed in 5 (31%) patients. Bone grafting was not necessary. FU was performed in 14/16 patients on average after 9 years (mean; range: 1.4–16.2 years). The mean AOFAS Midfoot Scale at FU for extra-articular type 2 fractures was 100 points, whereas in intra-articular fractures (Type 3) and fractures associated with mid-tarsal disruption (type 5b) worse results were found (95 and 66 points, accordingly).Conclusion
This rare injury shows inhomogenous morphologies and offers different treatment approaches. Extra-articular Fenton type 2 lesions are the most common type of cuboid fracture in children (69%). A potential loss of length of the lateral column must be considered. In contrast to adults, type 1, 4, and 5a fractures were not found in our cohort of children and adolescents. Lower scores of the AOFAS Midfoot Scale were found with either intra-articular involvement or associated midfoot lesions. 相似文献5.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
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Jamaal L. Benjamin MD PhD Rebecca Dennis DO Stacy White Jr MD David Munson MD Sudha A. Anupindi MD Maciej Piskunowicz MD Kassa Darge MD PhD Ami Gokli MD Misun Hwang MD 《Journal of ultrasound in medicine》2020,39(5):1031-1036
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates. 相似文献
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Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study
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10.
Weiyu Ye Anna Olsson-Brown Robert A. Watson Vincent T. F. Cheung Robert D. Morgan Isar Nassiri Rosalin Cooper Chelsea A. Taylor Umair Akbani Oliver Brain Rubeta N. Matin Nicholas Coupe Mark R. Middleton Mark Coles Joseph J. Sacco Miranda J. Payne Benjamin P. Fairfax 《British journal of cancer》2021,124(10):1661
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma 相似文献