Backgrounds: Fecal occult blood testing (FOBT) is commonly used in colorectal cancer screening programs. Many studies have compared different FOBT methods, but the correlation between traditional red cell microscopy and FOBT remains unclear. Objectives: 1) To evaluate the rate of positive FOBT in patients with different disease groups; 2) To compare the sensitivity and specificity of red blood cells detection in fresh stool by microscopy technique and FOBT. Materials and methods: This was a cross-sectional study involving 120 patients from Hue University of Medicine and Pharmacy Hospital who requested a stool test from 4/2021 to 4/2022. Fresh stool samples were examined for the presence of red blood cells using traditional microscopy and FOBT technique. Results: The overall positivity rate of FOBT was 20%, and in the group of gastrointestinal diseases (n = 24), clinical anemia (n = 21), hepatobiliary diseases (n = 26) and other diseases (n = 49), it was 37.5%, 23.8%, 11.5% and 14.3%, respectively. In comparison with the FOBT technique, microscopic RBC detection had a sensitivity of 33.3% and a specificity of 100%. Conclusions: A high rate of fecal occult blood tests was observed in patients with gastrointestinal disorders. Microscopic erythrocyte detection has low sensitivity and many disadvantages compared to the rapid test. This rapid test should be widely used in clinical practice to aid in the diagnosis of gastrointestinal bleeding

Glioblastoma (GBM) is the most aggressive malignant brain tumor and has a high mortality rate. Photodynamic therapy (PDT) has emerged as a promising approach for the treatment of malignant brain tumors. However, the use of PDT for the treatment of GBM has been limited by its low blood‒brain barrier (BBB) permeability and lack of cancer-targeting ability. Herein, brain endothelial cell-derived extracellular vesicles (bEVs) were used as a biocompatible nanoplatform to transport photosensitizers into brain tumors across the BBB. To enhance PDT efficacy, the photosensitizer chlorin e6 (Ce6) was linked to mitochondria-targeting triphenylphosphonium (TPP) and entrapped into bEVs. TPP-conjugated Ce6 (TPP-Ce6) selectively accumulated in the mitochondria, which rendered brain tumor cells more susceptible to reactive oxygen species-induced apoptosis under light irradiation. Moreover, the encapsulation of TPP-Ce6 into bEVs markedly improved the aqueous stability and cellular internalization of TPP-Ce6, leading to significantly enhanced PDT efficacy in U87MG GBM cells. An in vivo biodistribution study using orthotopic GBM-xenografted mice showed that bEVs containing TPP-Ce6 [bEV(TPP-Ce6)] substantially accumulated in brain tumors after BBB penetration via transferrin receptor-mediated transcytosis. As such, bEV(TPP-Ce6)-mediated PDT considerably inhibited the growth of GBM without causing adverse systemic toxicity, suggesting that mitochondria are an effective target for photodynamic GBM therapy.