Application of In Vivo Ca
Long-Jun Wu in Nonclassical Ion Channels in the Nervous System, 2021
Ca 2+ is an important second messenger for neurotransmitter release, membrane depolarization, and homeostasis of all cells in the brain. The concentration of the free calcium ions in the cytoplasm increases about tenfold during action compared to resting. Since neuronal activities involve the fluctuation of intracellular Ca 2+ concentration, such fluctuation can carry information on neuronal activities that is closely correlated with signal processing in the brain. Two-photon microscopy is a useful technique to study the circuit level mechanism of neurological disorders, such as autism spectrum disorders. Single-photon microscope imaging of live animals has been widely adopted in neuroscience research. A large number of brain areas in freely behaving animals have been imaged to explore the brain functions including spatial navigation, complex motor tasks, memory formation and linking, and social behaviours. The miniature fluorescence microscope has also been used to uncover dysfunctional neural circuits underlying behavioral deficits of neurological disorders.
Other Light Microscopical Techniques Applied to Fibres
P.H. Greaves, B.P. Saville in Microscopy of Textile Fibres, 2020
A fluorescence microscope uses a light source to provide an intense broad band emission of radiation, typically from 300 to 700 nm. The lost energy is emitted as light of longer wavelength than that which caused the initial excitation — generally visible light when the incident exciting light has been near ultraviolet. The most obvious difference between a conventional light microscope and an Fourier-transform infrared (FTIR) microscope is in the optics. A complimentary technique to FTIR microscopy is that of microspot Raman spectroscopy, in which the minor proportion of IR light which undergoes a change in wavelength on interacting with a material is measured. The wavelengths which are transmitted or absorbed are determined by the chemical bonds present in the material, and the resulting IR spectrum is characteristic of the compound and may be used for identification.
The Application of Genetic Tests in an Assisted Reproduction Unit: Sperm FISH
Nicolás Garrido, Rocio Rivera in A Practical Guide to Sperm Analysis, 2017
Intracytoplasmic sperm injection (ICSI) allows overcoming the natural barrier offered by the oocyte to sperm fertilization in couples with severe male factor infertility. Sperm fluorescence in situ hybridization (FISH) uses fluorescence DNA probes directed to specific DNA sequences in the interphase sperm nuclei. Visualizing the hybridization signals using fluorescence microscopy, it is possible to identify numerical chromosome abnormalities in the nucleus of ejaculated, epididymal, and testicular sperm. Sperm FISH analyses corroborate previous reports with altered meiosis in infertile men, as they have shown higher aneuploidy rates for chromosome 21 and sex chromosomes due to meiotic nondisjunction. Sperm heads have a tightly compacted nucleus due to the presence of disulfide bridges between protamines; this condensation of nuclear chromatin makes it inaccessible to DNA probes. Double-strand DNA denaturation of the sperm and FISH probes is carried out after incubation at high temperature. The hybridization signals are visualized using a fluorescent microscope equipped with specific filters for each fluorochrome.
Measuring Low Concentrations of Fluorescent Magnetic Nanoparticles by Fluorescence Microscopy
Published in International Journal of Optomechatronics, 2013
Zhaolong Shen, Katherine Chen, Benjamin Shapiro
We introduce a method called particle images counting (PIC) to quantify low concentrations of fluorescent magnetic nanoparticles in liquid samples. The sample is diluted with gelatin and a known volume is placed on a microscope slide. The magnetic particles are pulled down to one surface of the slide by a magnet held on the opposing surface before the gelatin is solidified to immobilize the particles. After imaging with fluorescence microscopy, the number of particles is counted using a vision algorithm. Preliminary results are shown to validate this method.
Fabrication of biodegradable PEG–PLA nanospheres for solubility, stabilization, and delivery of curcumin
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2017
Hongying Liang, Joel M Friedman, Parimala Nacharaju
Curcumin is an effective and safe anticancer agent, and also known to induce vasodilation, but its hydrophobicity limits its clinical application. In this study, a simple emulsion method was developed to prepare biodegradable poly (ethylene glycol)–poly (lactic acid) (PEG–PLA) nanospheres to encapsulate curcumin to improve its solubility and stability. The nanoparticle size was around 150 nm with a narrow size distribution. Fluorescence microscopy showed that curcumin encapsulated PEG-PLA nanospheres were taken up rapidly by Hela and MDA-MB-231 cancer cells. This novel nanoparticulate carrier may improve the bioavailability of curcumin without affecting its anticancer properties.
Functional blood flow patterns of the endolymphatic sac in the rat
Published in Acta Oto-Laryngologica, 2009
Conclusion. Visualization of the endolymphatic sac vascular network under video fluorescence microscopy showed a typical microvascular organization. The microvascular arrangement and the microcirculation may reflect a functional state of the endolymphatic sac. Damage or change of the blood circulation following endolymphatic sac surgery is discussed. Objectives. To visualize and study the dynamic microcirculation of the endolymphatic sac in live rats. Method. An experimental animal study using in vivo video fluorescence microscopy. Results. Visualization of the endolymphatic sac vascular network showed a typical microvascular organization. The endolymphatic sac appeared hypervascular and independent from other vascular systems. The microcirculation of the endolymphatic sac was supplied by ramification of a single artery, while venous trunks perpendicular to the length of the endolymphatic sac served as return paths for the microcirculation. The blood flow pattern was highly variable between rats.