High-Resolution Microscopic Characterization of Tunneling Nanotubes in Living U87 MG and LN229 Glioblastoma Cells.

Tunneling nanotubes (TNTs) are fine, nanometer-sized membrane connections between distant cells that provide an efficient communication tool for cellular organization. TNTs are thought to play a critical role in cellular behavior, particularly in cancer cells. The treatment of aggressive cancers such as glioblastoma remains challenging due to their high potential for developing therapy resistance, high infiltration rates, uncontrolled cell growth, and other aggressive features. A better understanding of the cellular organization via cellular communication through TNTs could help to find new therapeutic approaches. In this study, we investigate the properties of TNTs in two glioblastoma cell lines, U87 MG and LN229, including measurements of their diameter by high-resolution live-cell stimulated emission depletion (STED) microscopy and an analysis of their length, morphology, lifetime, and formation by live-cell confocal microscopy. In addition, we discuss how these fine compounds can ideally be studied microscopically. In particular, we show which membrane-labeling method is suitable for studying TNTs in glioblastoma cells and demonstrate that live-cell studies should be preferred to explore the role of TNTs in cellular behavior. Our observations on TNT formation in glioblastoma cells suggest that TNTs could be involved in cell migration and serve as guidance.

Synthesis and evaluation of thermoluminescence properties of ZrO2:Mg for radiotherapy dosimetry.

This study aimed to investigate the thermoluminescent properties of ZrO2:Mg irradiated with a 6 MV X-ray beam and its potential application in radiotherapy dosimetry. ZrO2 powder was synthesized using the sol-gel method and Mg was used as a dopant. Irradiations were performed with ZrO2:Mg chips located at the center of a 10 × 10 cm2 radiation field at a source surface distance of 100 cm, below a stack of solid water slabs, at the depth of maximum absorbed dose. The investigated characteristics of the material included linearity with radiation dose, reproducibility, accuracy, sensitivity and fading. Regarding the intrinsic difference of the samples, the glow curves of the investigated ZrO2:Mg chips exposed to 1 Gy of 6 MV X-rays exhibited three or four peaks. The ZrO2:Mg samples showed a 47% fading at 24 h after irradiation, and the reproducibility of the thermoluminescence reading of ZrO2:Mg for equal irradiation conditions was ± 21%. The thermoluminescence response of the investigated ZrO2:Mg samples to various absorbed doses from 0.5 to 2.5 Gy showed a gentle increase of the thermoluminescence intensity with increasing absorbed dose. The obtained results show that ZrO2:Mg is not an appropriate candidate for X-ray photons in radiotherapy, due to low thermoluminescence peak temperature, low reproducibility, low sensitivity to various absorbed doses and significant fading.