Terahertz radiation may not alter rat basophilic leukemia cell membrane permeability to propidium iodide

Terahertz radiation (THz) technology is fast-growing, with applications in sensing, security, monitoring and pharmaceutical industries. Since it is non-invasive, THz has been used as a diagnostic and therapeutic tool in medicine but its specific effects on biological systems is still largely under-studied. THz has been used to image tissues and cells mainly because it allows for identification of morphological features without the need for fluorescent or radioactive labels, but the potential effects of high intensities of THz radiation are currently not well understood. One of the hypotheses that has been proposed for possible effects of THz on living cells, is that it disrupts the cell membrane and induces increased permeability. To test this hypothesis we exposed a rat basophilic leukemia cell line (RBL-2H3) to non-thermal intense THz radiation (duration, dose, etc) and observed the internalization of propidium iodide, a fluorescent intercalating agent that binds to DNA. We did not observe any changes in RBL-2H3 fluorescence following exposure to these intense THz pulses suggesting that exposure of RBL-2H3 to THz radiation may not increase their membrane permeability. These experiments were preliminary and further optimization and analysis is required before we can make definitive conclusions. However, our preliminary observations have set a baseline of RBL-2H3 internalization of propidium iodide, show that it is possible to expose RBL-2H3 cells to THz radiation using our configuration, and set the stage for future experiments.

Anti-Food Allergic Compounds from Penicillium griseofulvum MCCC 3A00225, a Deep-Sea-Derived Fungus

Ten new (1–10) and 26 known (11–36) compounds were isolated from Penicillium griseofulvum MCCC 3A00225, a deep sea-derived fungus. The structures of the new compounds were determined by detailed analysis of the NMR and HRESIMS spectroscopic data. The absolute configurations were established by X-ray crystallography, Marfey’s method, and the ICD method. All isolates were tested for in vitro anti-food allergic bioactivities in immunoglobulin (Ig) E-mediated rat basophilic leukemia (RBL)-2H3 cells. Compound 13 significantly decreased the degranulation release with an IC50 value of 60.3 μM, compared to that of 91.6 μM of the positive control, loratadine.

Mechanistic Studies of the Antiallergic Activity of Phyllanthus amarus Schum. & Thonn. and Its Compounds

Phyllanthus amarus Schum. & Thonn. (Phyllanthaceae) is a medicinal plant that is commonly used to treat diseases such as asthma, diabetes, and anemia. This study aimed to examine the antiallergic activity of P. amarus extract and its compounds. The antiallergic activity was determined by measuring the concentration of allergy markers release from rat basophilic leukemia (RBL-2H3) cells with ketotifen fumarate as the positive control. As a result, P. amarus did not stabilize mast cell degranulation but exhibited antihistamine activity. The antihistamine activity was evaluated by conducting a competition radioligand binding assay on the histamine 1 receptor (H1R). Four compounds were identified from the high performance liquid chromatography (HPLC) analysis which were phyllanthin (1), hypophyllanthin (2), niranthin (3), and corilagin (4). To gain insights into the binding interactions of the most active compound hypophyllanthin (2), molecular docking was conducted and found that hypophyllanthin (2) exhibited favorable binding in the H1R binding site. In conclusion, P. amarus and hypophyllanthin (2) could potentially exhibit antiallergic activity by preventing the activation of the H1 receptor.

Multimodal fluorescently labeled polymer-coated GdF3 nanoparticles inhibit degranulation in rat basophilic leukemia (RBL) cells

Multimodal gadolinium fluoride nanoparticles belong to potential contrast agents useful for bimodal optical fluorescence and magnetic resonance imaging. However, the metallic nature of the nanoparticles, similarly to some paramagnetic iron...