Search results for "Fluorescence intensity"
showing 10 items of 17 documents
Noninvasive Monitoring of Lesion Size in a Heterologous Mouse Model of Endometriosis
2019
Here, we describe a protocol for the implementation of a heterologous mouse model in which progression of endometriosis can be assessed in real time through noninvasive monitoring of fluorescence emitted by implanted ectopic human endometrial tissue. For this purpose, biopsies of human endometrium are obtained from donor women ongoing oocyte donation. Human endometrial fragments are cultured in the presence of adenoviruses engineered to express cDNA for the reporter fluorescent protein mCherry. Upon visualization, labeled tissues with an optimal rate of fluorescence after infection are subsequently chosen for the implantation in recipient mice. One week prior to the implantation surgery, re…
Red Cell Membrane Protein Lateral Mobility in Diabetes Mellitus
1992
In a group of 24 diabetics subdivided for type, we evaluated the red cell membrane protein lateral mobility marking intact red cells with pyrene-3-maleimide (3-PM) and calculating the dimer to monomer fluorescence intensity ratio (Iex/Im). The same fluorescent parameter was determined in a group of 13 normal controls. From the obtained data, it is evident that the red cell membrane protein lateral mobility clearly discriminates normals from diabetics of type 1 and 2. In normals and in diabetics of type 1 and 2 no relationship is present between this fluorescent determinant and the glycometabolic parameters (FBGL and HbA1c); considering all the diabetics, a negative relationship is evident b…
Parallel Measurements of in-vivo Skin Autofluorescence Lifetimes and Photobleaching Rates
2015
Experimental methodology for parallel measurements of in-vivo skin autofluorescence (AF) lifetimes and photo-bleaching dynamic has been developed and tested. The AF lifetime decay distributions were periodically collected from fixed tissue area with subsequent detection of the fluorescence intensity decrease dynamic at different time shifts after the pulse excitation. Temporal distributions of skin AF lifetimes and bleaching dynamic were collected and analyzed by means of commercial time-correlated single photon counting system. Details of the equipment and data processing are described as well as some measurement results that confirm the feasibility of the proposed technology.
[Cr(ddpd) 2 ] 3+ : A Molecular, Water‐Soluble, Highly NIR‐Emissive Ruby Analogue
2015
Bright, long-lived emission from first-row transition-metal complexes is very challenging to achieve. Herein, we present a new strategy relying on the rational tuning of energy levels. With the aid of the large N-Cr-N bite angle of the tridentate ligand ddpd (N,N'-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine) and its strong σ-donating capabilities, a very large ligand-field splitting could be introduced in the chromium(III) complex [Cr(ddpd)2](3+), that shifts the deactivating and photoreactive (4)T2 state well above the emitting (2)E state. Prevention of back-intersystem crossing from the (2)E to the (4)T2 state enables exceptionally high near-infrared phosphorescence quantum yields a…
Fluorescence and circular dichroism spectroscopy to understand the interactions between cyclodextrins and α-galactosidase from green coffee beans
2017
Abstract The potential of fluorescence measurement and circular dichroism spectroscopy (CDSP) to evaluate the interaction between cyclodextrins (CDs) (CD cavity size, concentration, pH, reaction time, and temperature as well as different side chain groups) and α-galactosidase was evaluated. A strong relationship was observed between α-galactosidase fluorescence intensity and CD cavity size, concentration, pH, reaction time, and temperature as well as different side chain groups. Therefore, it can be concluded that fluorescence intensity measurement can be a promising tool to ascertain β-CD-α-galactosidase interactions. CDSP is also an interesting tool to understand β-CD-α-galactosidase inte…
Deep Convolutional Neural Network for HEp-2 fluorescence intensity classification
2019
Indirect ImmunoFluorescence (IIF) assays are recommended as the gold standard method for detection of antinuclear antibodies (ANAs), which are of considerable importance in the diagnosis of autoimmune diseases. Fluorescence intensity analysis is very often complex, and depending on the capabilities of the operator, the association with incorrect classes is statistically easy. In this paper, we present a Convolutional Neural Network (CNN) system to classify positive/negative fluorescence intensity of HEp-2 IIF images, which is important for autoimmune diseases diagnosis. The method uses the best known pre-trained CNNs to extract features and a support vector machine (SVM) classifier for the …
An Automatic HEp-2 Specimen Analysis System Based on an Active Contours Model and an SVM Classification
2019
The antinuclear antibody (ANA) test is widely used for screening, diagnosing, and monitoring of autoimmune diseases. The most common methods to determine ANA are indirect immunofluorescence (IIF), performed by human epithelial type 2 (HEp-2) cells, as substrate antigen. The evaluation of ANA consist an analysis of fluorescence intensity and staining patterns. This paper presents a complete and fully automatic system able to characterize IIF images. The fluorescence intensity classification was obtained by performing an image preprocessing phase and implementing a Support Vector Machines (SVM) classifier. The cells identification problem has been addressed by developing a flexible segmentati…
Automated analysis of images for molecular quantification in immunohistochemistry.
2018
The quantification of the expression of different molecules is a key question in both basic and applied sciences. While protein quantification through molecular techniques leads to the loss of spatial information and resolution, immunohistochemistry is usually associated with time-consuming image analysis and human bias. In addition, the scarce automatic software analysis is often proprietary and expensive and relies on a fixed threshold binarization. Here we describe and share a set of macros ready for automated fluorescence analysis of large batches of fixed tissue samples using FIJI/ImageJ. The quantification of the molecules of interest are based on an automatic threshold analysis of im…
Fluorometric determination of diphenhydramine by flow-injection analysis
1992
A sensitive, rapid and simple flow injection procedure for the determination of diphenhydramine has been designed based on a fluorometric approach. An aqueous solution of diphenhydramine is injected into a carrierreagent stream containing Ce(IV) in dilute sulphuric acid and the fluorescence intensity of the Ce(III) produced is monitored. Chemical, FIA and instrumental variables were optimized. Analytical features of the method are: linear range 0.2–2 ppm, precision 0.7%, sample throughput 80/h. The influence of some foreign substances which can be found in typical pharmaceutical samples containing diphenhydramine was also investigated. The diphenhydramine content of a pharmaceutical prepara…
Evaluation of the interelemental effect in X-ray fluorescence analysis by the total addition method
1992
An algorithm for quantifying interelemental effects in X-ray fluorescence techniques is developed. By applying an addition process, the ratio between the mass absorption coefficients of the analyte and the unknown sample (μi*/μs*) is calculated to correct the fluorescence intensity of the element to be determined and linearize the I-c calibration plot. This coefficient can be calculated graphically and numerically. The method is applied to the determination of tin in lead alloys with good results over wide concentration ranges.