Search results for " Imaging"
showing 10 items of 6262 documents
Metabolic Imaging in Multicellular Spheroids of Oncogene-transfected Fibroblasts
2000
Four rat embryo fibroblast (REF) cell lines with defined oncogenic transformation were used to study the relationship between tumorigenic conversion, metabolism, and development of cell death in a 3D spheroid system. Rat1 (spontaneously immortalized) and M1 ( myc-transfected) fibroblasts represent early nontumorigenic transformation stages, whereas Rat1-T1 (T24Ha- ras-transfected Rat1) and MR1 ( myc/T24Ha- ras-co-transfected REF) cells express a highly tumorigenic phenotype. Localized ATP, glucose, and lactate concentrations in spheroid median sections were determined by imaging bioluminescence. ATP concentrations were low in the nonproliferating Rat1 aggregates despite sufficient oxygen an…
Direct Visualization of the Conformational Dynamics of Single Influenza Hemagglutinin Trimers
2018
Influenza hemagglutinin (HA) is the canonical type I viral envelope glycoprotein and provides a template for the membrane-fusion mechanisms of numerous viruses. The current model of HA-mediated membrane fusion describes a static "spring-loaded" fusion domain (HA2) at neutral pH. Acidic pH triggers a singular irreversible conformational rearrangement in HA2 that fuses viral and cellular membranes. Here, using single-molecule Förster resonance energy transfer (smFRET)-imaging, we directly visualized pH-triggered conformational changes of HA trimers on the viral surface. Our analyses reveal reversible exchange between the pre-fusion and two intermediate conformations of HA2. Acidification of p…
Complexity analysis of cortical surface detects changes in future Alzheimer's disease converters
2017
Alzheimer's disease (AD) is a neurological disorder that creates neurodegenerative changes at several structural and functional levels in human brain tissue. The fractal dimension (FD) is a quantitative parameter that characterizes the morphometric variability of the human brain. In this study, we investigate spherical harmonic-based FD (SHFD), thickness, and local gyrification index (LGI) to assess whether they identify cortical surface abnormalities toward the conversion to AD. We study 33 AD patients, 122 mild cognitive impairment (MCI) patients (50 MCI converters and 29 MCI nonconverters), and 32 healthy controls (HC). SHFD, thickness, and LGI methodology allowed us to perform not only …
Generation of an inducible RPE-specific Cre transgenic-mouse line.
2018
The retinal pigment epithelium (RPE) is an epithelial monolayer in the back of the vertebrate eye. RPE dysfunction is associated with retinal degeneration and blindness. In order to fully understand how dysregulation affects visual function, RPE-specific gene knockouts are indispensable. Since the currently available RPE-specific Cre recombinases show lack of specificity or poor recombination, we sought to generate an alternative. We generated a tamoxifen-inducible RPE-specific Cre transgenic mouse line under transcriptional control of an RPE-specific Tyrosinase enhancer. We characterized the Cre-mediated recombinant expression by crossing our RPE-Tyrosinase-CreErT2 mouse line with the tdTo…
Secondary Progression in Multiple Sclerosis: Neuronal Exhaustion or Distinct Pathology?
2016
Prevention of progression in neurological diseases, particularly in multiple sclerosis (MS) but also in neurodegenerative diseases, remains a significant challenge. MS patients switch from a relapsing-remitting to a progressive disease course, but it is not understood why and how this conversion occurs and why some patients never experience disease progression. Do aging and accumulation of neuronal damage induce progression, or do cognitive symptoms and accelerated grey matter (GM) atrophy point to distinct processes affecting networks? This review weighs accepted dogma against real data on the secondary progressive phase of the disease, highlighting current challenges in this important fie…
Odor-induced electrical and calcium signals from olfactory sensory neurons in situ
2018
Electrophysiological recording and optical imaging enable the characterization of membrane and odorant response properties of olfactory sensory neurons (OSNs) in the nasal neuroepithelium. Here we describe a method to record the responses of mammalian OSNs to odorant stimulations in an ex vivo preparation of intact olfactory epithelium. The responses of individual OSNs with defined odorant receptor types can be monitored via patch-clamp recording or calcium imaging.
No diagnostic utility of antibody patterns against Klebsiella pneumoniae capsular serotypes in patients with axial spondyloarthritis vs. patients wit…
2017
OBJECTIVES: To investigate whether antibody response patterns against Klebsiella pneumoniae capsular serotypes can discriminate patients with axial spondyloarthritis (axSpA) from patients with non-specific low back pain (LBP).METHOD: Immunoglobulin (Ig)G and IgA antibodies against K. pneumoniae capsular serotypes K2, K26, K36, and K50 were measured, and antibody seropositivity compared between groups and analysed for patient correlation in five different groups: (a) 96 patients fulfilling the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axSpA; (b) 38 patients with either a positive magnetic resonance imaging (MRI) scan as defined by ASAS or a posi…
Super-resolution binding activated localization microscopy through reversible change of DNA conformation
2018
ABSTRACT Methods of super-resolving light microscopy (SRM) have found an exponentially growing range of applications in cell biology, including nuclear structure analyses. Recent developments have proven that Single Molecule Localization Microscopy (SMLM), a type of SRM, is particularly useful for enhanced spatial analysis of the cell nucleus due to its highest resolving capability combined with very specific fluorescent labeling. In this commentary we offer a brief review of the latest methodological development in the field of SMLM of chromatin designated DNA Structure Fluctuation Assisted Binding Activated Localization Microscopy (abbreviated as fBALM) as well as its potential future app…
MassARRAY determination of somatic oncogenic mutations in solid tumors: Moving forward to personalized medicine.
2016
This article will review the impact of the recently developed MassARRAY technology on our understanding of cancer biology and treatment. Analysis of somatic mutations is a useful tool in selecting personalized therapy, and for predicting the outcome of many solid tumors. Here, we review the literature on the application of MassARRAY technology (Sequenom Hamburg, Germany) to determine the mutation profile of solid tumors from patients. We summarize the use of commercially available panels of mutations - such as OncoCarta™ or other combinations - and their concordance with results obtained by using other technologies, such as next generation sequencing.
Adult Neurogenesis Is Sustained by Symmetric Self-Renewal and Differentiation
2018
Somatic stem cells have been identified in multiple adult tissues. Whether self-renewal occurs symmetrically or asymmetrically is key to understanding long-term stem cell maintenance and generation of progeny for cell replacement. In the adult mouse brain, neural stem cells (NSCs) (B1 cells) are retained in the walls of the lateral ventricles (ventricular-subventricular zone [V-SVZ]). The mechanism of B1 cell retention into adulthood for lifelong neurogenesis is unknown. Using multiple clonal labeling techniques, we show that the vast majority of B1 cells divide symmetrically. Whereas 20%-30% symmetrically self-renew and can remain in the niche for several months before generating neurons, …