China
Africa
Explore chapters and articles related to this topic
Transport of Protein-Bound Radiotracers Into Tissues*
Published in Lelio G. Colombetti, Biological Transport of Radiotracers, 2020
The above discussion has emphasized the importance of two factors, debinding rates and capillary transit times, which determine whether a protein-bound ligand enters tissues. A third factor, membrane permeability, is of equal importance. A ligand may unidirectionally dissociate well within a capillary transit time; however, if the tendency for the ligand to diffuse through the membrane is slow relative to the transit time, then the ligand will simply reassociate with the plasma protein. Under these conditions, no protein-bound hormone will enter the tissue and the availability of hormone will be accurately reflected by in vitro measurements of free hormone. Membrane permeability is a function of (1) the free diffusion of the ligand owing to lipid-mediation, or (2) the facilitated diffusion of the compound due to carrier-mediation.
Role of Tumor Cell Membrane in Hyperthermia
Published in Leopold J. Anghileri, Jacques Robert, Hyperthermia In Cancer Treatment, 2019
Concerning membrane transport and permeability, early studies have suggested the presence of domains within the membranes related to that physiological activity,74–78 but the correlation between phase transition and cell membrane permeability is not always evident.79
Lab-on-a-Chip-Based Devices for Rapid and Accurate Measurement of Nanomaterial Toxicity
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
Mehenur Sarwar, Amirali Nilchian, Chen-zhong Li
The cell membrane has an extremely complex structure known as the bilayer lipid membrane (BLM). The BLM encapsulates cells and acts as an ultimate barrier that defends cell compartments by establishing stringent selective permeability. Membrane permeability is determined by cell function and activity. BLM has a thickness of about 7 nm and electrical properties which can be modelled as a high-volume capacitor with a capacity of about 1 μF/cm2 and very low conductivity of 6−10 S/m (Grimnes and Martinsen 2008).
Toxicity and biomarkers of micro-plastic in aquatic environment: a review
Published in Biomarkers, 2021
Kamrul Hassan Suman, Md Niamul Haque, Md Jamal Uddin, Most Shirina Begum, Mahmudul Hasan Sikder
LPO is one kind of chain reaction usually occurs at molecular level causing oxidative damage to lipoproteins, cell membranes, and other lipid-containing organelles (Nam 2011). These changes result in alterations of membrane permeability and accelerate the entrance of toxic agents into the cells (Ayala et al. 2014). The content of malondialdehyde (MDA), which is a toxic product of lipid peroxidation, indirectly reflects the level of ROS and induces cellular damage due to lipid peroxidation. Thus, the degree of MDA is considered as a common non-specific biomarker of exposure to environmental contaminants including MPs (Azevedo et al. 2009, Prokić et al. 2019). Considerable increase in LPO was recorded in the brain of Dicentrarchus labrax as a response to the MP, as well as to a mixture of MPs and mercury (Barboza et al. 2018). Although ROS increased, the degree of oxidative damage to lipids reduced in the digestive gland of the marine mussel, Mytilus spp. after 7 days of exposure to PS-microbeads (a mixture of 2 and 6 mm) (Paul-Pont et al. 2016). Similar phenomenon was found in the gills of Scrobicularia plana due to activation of antioxidative defense enzymes (Ribeiro et al. 2017). The responses of lipid peroxidation and antioxidant enzymes activity are interlinked, thus the combined study as biomarker for evaluating MPs contamination in aquatic system could be give better utility, rather than utilising separately (Prokić et al. 2019).
Analysis of membrane permeability due to synergistic effect of controlled shock wave and electric field application
Published in Electromagnetic Biology and Medicine, 2020
Shadeeb Hossain, Ahmed Abdelgawad
Comparative studies between different technologies can be an effective methodology to realize the changes in the membrane permeability under perturbation. An important factor for sonoporation involves the application of high-frequency alternating waves in the range of MHz and can contribute to excessive heating and tissue tear at high amplitudes. Radiofrequency (RF) treatment, similarly causes excessive Joule heating under-prolonged exposure time. Cryosurgery, which involves freezing the tumor cells might not be an effective method when combined with chemotherapeutic drugs (https://www.healthline.com/health/cryosurgery#risks). In contrast, electrochemotherapy is an effective clinical treatment for certain types of cancer cells (Cadossi et al. 2014; Hofmann et al. 1999; Okino and Mohri 1987). Controlled shock waves, on the other hand, can be directed for an effective treatment of deep tissue or malignant cells without severely affecting the surrounding healthy or normal neighboring cells (http://eswt.net/how-do-shock-waves-differ-to-ultrasound).
Evaluation of combined effect of hyperthermia and ionizing radiation on cytotoxic damages induced by IUdR-loaded PCL-PEG-coated magnetic nanoparticles in spheroid culture of U87MG glioblastoma cell line
Published in International Journal of Radiation Biology, 2018
Parisa Rezaie, Samideh Khoei, Sepideh Khoee, Sakine Shirvalilou, Seied Rabi Mahdavi
Hyperthermia or thermotherapy is a non-ionizing therapeutic modality that increases the temperature in tissues in order to changing the function of the cellular structures (Qi et al. 2015). Hyperthermia decreased the fundamental biochemical processes such as respiration, glycolysis and polymerization of nucleic acid and/or proteins (Strom 1977). Also increase the temperature affect fluidity and stability of cellular membranes and it cause loss of cell membrane permeability, in fact membrane change indicate an important target in hyperthermic cell death (Hildebrandt et al. 2002, Konings and Ruifrok 1985). It has been shown that hyperthermia enhancement the radiation damage by sensitize cells to radiation and clinical studies have indicated that it is beneficial in combination with radiotherapy (GM 1982; van der Zee et al. 2000). Hyperthermia with inhibition of the repair of radiation-induced DNA damage, sensitivity of hypoxic cells, low pH regions and the cells in S-phase where these areas are relatively resistant to X-rays, is able to increase the cytotoxic effect of radiotherapy (Wust et al. 2002).