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Extracorporeal Purging of Bone Marrow Grafts by Dye-Sensitized Photoirradiation
Published in Adrian P. Gee, BONE MARROW PROCESSING and PURGING, 2020
The mechanism of action of MC 540 is not yet completely understood. Direct observations with the fluorescence microscope indicate that MC 540 binds to the plasma membrane of intact cells. Binding to intracellular membranes (e.g., nuclear envelope) is only observed after prolonged exposure to dye and light, i.e., after most cells have sustained lethal photodynamic damages. Staining of intracellular structures may, however, precede the uptake of trypan blue. The absorption and fluorescence emission spectra of cell-bound MC 540 are red-shifted, indicating that the dye localizes in a lipophilic environment. Fluorescence quenching and fluorescence resonance energy transfer experiments show that both the dye monomer and the dye dimer are capable of partitioning into the lipid bilayer.65 However, accumulation of dye in the plasma membrane is minimal unless cells are also exposed to light for at least a short period of time. Therefore, to effectively kill cells by MC 540-sensitized photoirradiation, cells must be simultaneously exposed to dye and light. With many other photosensitizers, it is customary to first stain the cells and then, after excess dye has been removed, expose them to light. The mechanism of the irradiation-dependent uptake of dye is not understood. It is conceivable that some photoirradiation-dependent modifications of the plasma membrane have to take place before the interior of the plasma membrane becomes accessible to dye molecules. An equally plausible explanation is that the plasma membrane is more accessible to certain photoisomers of the dye.
ExperimentaL Oral Medicine
Published in Samuel Dreizen, Barnet M. Levy, Handbook of Experimental Stomatology, 2020
Samuel Dreizen, Barnet M. Levy
Microscopic reflections of early radiation injury in the rat parotid gland were elucidated by Sholley et al.100 Female Sprague-Dawley rats weighing between 170 and 230 g received either 1600 or 6400 R in a single exposure delivered at a rate of approximately 190 r/min. Trypan blue and colloidal carbon were used as tracers to detect abnormal vascular permeability. Trypan blue was administered in a dose of 0.2 mℓ of a 2% solution in saline per 100 g body weight. The tracers were injected into the lateral tail vein of the anesthetized rats. Some rats received both tracers; most received only one. Circulation time ranged between 10 and 90 min before sacrifice. Parotid glands were examined by light and electron microscopy after appropriate fixing and processing. For light microscopy, the glands were fixed in 10% formalin and prepared for paraffin sections stained with hematoxylin and eosin and with special stains. For electron microscopy, the glands were fixed in Karnowsky’s fixative, postfixed in osmium tetraoxide, dehydrated in ethanol, and embedded in Epon®.
Pars plana vitrectomy for diabetic macular edema associated with posterior hyaloidal traction
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Sophie J Bakri, Peter K Kaiser, Hilel Lewis
We usually perform this surgery without the use of adjuvant stains. However, in cases where an edge of hyaloid may be particular difficult to identify, intraoperative staining with 0.05% indocyanine green or triamcinolone acetonide is useful to visualize the hyaloid. Trypan blue is currently not approved by the US Food and Drug Administration (FDA), but the experience of our European colleagues has shown that it may be a useful stain.
Dissolving microneedle patch-assisted transdermal delivery of methotrexate improve the therapeutic efficacy of rheumatoid arthritis
Published in Drug Delivery, 2023
Weiman Zhao, Lijie Zheng, Jianhui Yang, Zihui Ma, Xinyi Tao, Qingqing Wang
To examine whether the microneedles could successfully penetrate the skin, in vitro and in vivo insertion experiments were performed. In in vitro experiments, the isolated dorsal skin of SD rats was penetrated using TB-loaded DMNPs for 5 min and removed afterward. Trypan blue was adopted because it stains internal tissues of skin through micropores and could not penetrate the SC itself (Cheng et al., 2020). Therefore, the conspicuous blue dots in isolated skin observed by a handheld microscope could indicate the puncture capability (Figure 3(J)). The effect of different concentrations of HA on puncture performance was also studied (Supplementary Figure S3). The results showed that the insertion ratios of 100 and 200 mg/mL HA were about 72% and 85% respectively, while the ratios of 300 mg/mL HA were more than 95%, which was therefore adopted to fabricate DMNPs for further studies.
Continuous Curvilinear Capsulorhexis – A Practical Review
Published in Seminars in Ophthalmology, 2022
The lens capsule is colorless, but in the presence of a normal red reflex, the anterior capsule can easily be seen once a flap is created and deflected.4 Adequate visualization of the capsule is a prerequisite for the creation of a proper capsulorhexis.29 Staining the capsule helps visualization but might also stiffen the capsule and make it more vulnerable to tears. Additionally, trypan blue may damage the corneal endothelial cells.5 For these reasons, the use of dyes should be reserved for cases in which visualization is difficult, such as white cataracts, brunescent cataracts, vitreous hemorrhage, and corneal clouding.4,5,29 Capsule staining can also be useful for teaching purposes.5,29 A few approaches are available.4,5 In the most common approach, the stain is injected under an air bubble and washed out after 10 to 15 seconds. Trypan blue is the most often used, and it is the only dye that is approved by the US Food and Drug Administration (FDA).4,5,16,29 In addition, in 2006, the American Academy of Ophthalmology (AAO) reported that there is level III evidence that trypan blue, indocyanine green and fluorescein effectively stain the capsule.29 However, fluorescein is less convenient to use, and indocyanine green has less intensity and is not recommended for brunescent cataracts due to reduced contrast with the lens.5 Gentian violet has been found to provide comparable results to trypan blue in terms of capsule visualization, but it has an inferior safety profile.5
Calcium alginate nanoparticle crosslinked phosphorylated polyallylamine to the controlled release of clindamycin for osteomyelitis treatment
Published in Drug Development and Industrial Pharmacy, 2021
Murugesan Gowri, Nachimuthu Latha, Kannan Suganya, Marudhamuthu Murugan, Mariappan Rajan
Cell viability of osteoblast-like cells (MG63) cultured with Ca-Alg/PPAA system and Ca-Alg/PPAA/Clindamycin system was evaluated. Five different concentrations (5 µg, 25 µg, 50 µg, 75 µg, and 100 µg) were used in both trypan blue assay and MTT cytotoxicity assay method. Figure 7 indicates Ca-Alg/PPAA and Ca-Alg/PPAA/Clindamycin in Trypan blue assay. The presence of calcium and phosphorous elements in the developed Ca-Alg/PPAA and Clindamycin loaded Ca-Alg/PPAA system exhibits better cell viability for MG63 cells. MTT assay indicates cells’ growth in the Clindamycin loaded Ca-Alg/PPAA system, which is presented in Figure 8. The results of the MTT assay show that MG63 cells are viable in the synthesized system. No significant differences were noticed for different concentrations of synthesized samples for the duration of 24 h. The drug-loaded system was found to be biocompatible in different concentrations, and the system showed 99% cell viability during the 24 h observation. The results showed no cytotoxicity reactivity, which indicates the developed system is biocompatible with MG63 cells and suitable for bone infection treatment [44].