Search results for " Fluorescence"

Two simple criteria to estimate an objective's performance when imaging in non design tissue clearing solutions

2019

Tissue clearing techniques are undergoing a renaissance motivated by the need to image fluorescent neurons, and other cells, deep in the sample without physical sectioning. Optical transparency is achieved by equilibrating tissues with high refractive index (RI) solutions. When the microscope objective is not perfectly matched to the RI of the cleared sample, aberrations are introduced. We present two simple-to-calculate numerical criteria predicting: (i) the degradation in image quality (brightness and resolution) from optimal conditions of any clearing solution/objective combination; (ii) which objective, among several available, achieves the highest resolution in a given medium. We deriv…

Computational Prediction of Position Effects of Apparently Balanced Human Chromosomal Rearrangements.

2017

Interpretation of variants of uncertain significance, especially chromosomal rearrangements in non-coding regions of the human genome, remains one of the biggest challenges in modern molecular diagnosis. To improve our understanding and interpretation of such variants, we used high-resolution three-dimensional chromosomal structural data and transcriptional regulatory information to predict position effects and their association with pathogenic phenotypes in 17 subjects with apparently balanced chromosomal abnormalities. We found that the rearrangements predict disruption of long-range chromatin interactions between several enhancers and genes whose annotated clinical features are strongly …

Study of novel anticancer 4-thiazolidinone derivatives

2016

Abstract 4-Thiazolidinones are a known class of prospective drug-like molecules, especially in the design of new anticancer agents. Two of the most prominent subtypes of these compounds are 5-ene-2-amino(amino)-4-thiazolidinones and thiopyrano[2,3-d]thiazoles. The latter are considered to be cyclic mimetics of biologically active 5-ene-4-thiazolidinones with similar pharmacological profiles. Therefore, the aim of this study was to evaluate the impact of 4-thiazolidinone-based compounds on cytotoxicity, the apoptotic process, and metabolism in the human squamous carcinoma (SCC-15) cell line. The SCC-15 cells were cultured in phenol red-free DMEM/F12 medium supplemented with 10% FBS, hydrocor…

Microtubule disruption changes endothelial cell mechanics and adhesion

2019

AbstractThe interest in studying the mechanical and adhesive properties of cells has increased in recent years. The cytoskeleton is known to play a key role in cell mechanics. However, the role of the microtubules in shaping cell mechanics is not yet well understood. We have employed Atomic Force Microscopy (AFM) together with confocal fluorescence microscopy to determine the role of microtubules in cytomechanics of Human Umbilical Vein Endothelial Cells (HUVECs). Additionally, the time variation of the adhesion between tip and cell surface was studied. The disruption of microtubules by exposing the cells to two colchicine concentrations was monitored as a function of time. Already, after 3…

Rescuing monopronucleated-derived human blastocysts: a model to study chromosomal topography and fingerprinting.

2021

Objective To quantify the percentage of monopronuclear-derived blastocysts (MNBs) that are potentially useful for reproductive purposes using classic and state-of-the-art chromosome analysis approaches, and to study chromosomal distribution in the inner cell mass (ICM) and trophectoderm (TE) for intertissue/intratissue concordance comparison. Design Prospective experimental study. Setting Single-center in vitro fertilization clinic and reproductive genetics laboratory. Patient(s) A total of 1,128 monopronuclear zygotes were obtained between June 2016 and December 2018. Intervention(s) MNBs were whole-fixed or biopsied to obtain a portion of ICM and 2 TE portions (TE1 and TE2) and were subse…

Easy One-Step Amplification and Labeling Procedure for Copy Number Variation Detection.

2019

Abstract Background The specific characteristics of copy number variations (CNVs) require specific methods of detection and characterization. We developed the Easy One-Step Amplification and Labeling procedure for CNV detection (EOSAL-CNV), a new method based on proportional amplification and labeling of amplicons in 1 PCR. Methods We used tailed primers for specific amplification and a pair of labeling probes (only 1 labeled) for amplification and labeling of all amplicons in just 1 reaction. Products were loaded directly onto a capillary DNA sequencer for fragment sizing and quantification. Data obtained could be analyzed by Microsoft Excel spreadsheet or EOSAL-CNV analysis software. We d…

Comparison between iMSD and 2D-pCF analysis for molecular motion studies on in vivo cells: The case of the epidermal growth factor receptor.

2018

Image correlation analysis has evolved to become a valuable method of analysis of the diffusional motion of molecules in every points of a live cell. Here we compare the iMSD and the 2D-pCF approaches that provide complementary information. The iMSD method provides the law of diffusion and it requires spatial averaging over a small region of the cell. The 2D-pCF does not require spatial averaging and it gives information about obstacles for diffusion at pixel resolution. We show the analysis of the same set of data by the two methods to emphasize that both methods could be needed to have a comprehensive understanding of the molecular diffusional flow in a live cell.

Visualising G-quadruplex DNA dynamics in live cells by fluorescence lifetime imaging microscopy

2020

Guanine rich regions of oligonucleotides fold into quadruple-stranded structures called G-quadruplexes (G4s). Increasing evidence suggests that these G4 structures form in vivo and play a crucial role in cellular processes. However, their direct observation in live cells remains a challenge. Here we demonstrate that a fluorescent probe (DAOTA-M2) in conjunction with fluorescence lifetime imaging microscopy (FLIM) can identify G4s within nuclei of live and fixed cells. We present a FLIM-based cellular assay to study the interaction of non-fluorescent small molecules with G4s and apply it to a wide range of drug candidates. We also demonstrate that DAOTA-M2 can be used to study G4 stability i…

Direct observation of alpha-lactalbumin, adsorption and incorporation into lipid membrane and formation of lipid/protein hybrid structures

2019

The interaction between proteins and membranes is of great interest in biomedical and biotechnological research for its implication in many functional and dysfunctional processes. We present an experimental study on the interaction between model membranes and alpha-lactalbumin (alpha-La). alpha-La is widely studied for both its biological function and its anti-tumoral properties. We use advanced fluorescence microscopy and spectroscopy techniques to characterize alpha-La-membrane mechanisms of interaction and alpha-La-induced modifications of membranes when insertion of partially disordered regions of protein chains in the lipid bilayer is favored. Moreover, using fluorescence lifetime imag…

2019

Purpose: Clear resection margins are paramount for good outcome in children undergoing solid tumor resections. Multiphoton microscopy (MPM) can provide high-resolution, real-time, intraoperative microscopic images of tumor tissue. Objective: This prospective international multicenter study evaluates the diagnostic accuracy, feasibility, and interobserver congruence of MPM in diagnosing solid pediatric tissue and tumors for the first time. Material and methods: Representative fresh sections from six different neonatal solid tissues (liver, lung, kidney, adrenal gland, heart muscle, testicle) and two types of typical pediatric solid tumors (neuroblastoma, rhabdomyosarcoma) with adjacent nonne…