The oxygen effect plays a great role in the treatment and diagnosis of cancers and in imaging. As will be shown, it is a complex issue with many different facets. There is no clear, concrete evidence for even the most logical and well known theories, which have not always been as such. New evidence arises quickly and is contested just as fast, leading to great debate, but also to great revelations into the true nature of an effect as complicated as the oxygen effect in radiobiology..
A brief history of the study of the oxygen effect will give some insight into the intensity of study and the ever changing attitudes and theories surrounding it. The first acknowledged study was made by Swartz in 1912. His contribution was realized during an experiment involving a radium applicator being used upon his arm. Swartz noticed that if he pressed the applicator to his skin with increasing force, a lessened reaction occurred. His idea was that the lessened blood flow resulted in the increased resistance. After Swartz, there was Holthusen in 1921. Holthusen irradiated the eggs of Ascaris, a small intestinal roundworm and noticed that if the irradiation took place in an anoxic, or oxygen free, environment, the resistance of the eggs was increased. He hypothesized that this was due to the halting of the cell cycle in the absence of oxygen, which was not the actual cause. (Biggar & Storey, 2009) Following Holthusen’s footsteps, Petry conducted a study involving the irradiation of vegetable seeds in varying levels of oxygenation. He found a correlation between the amount of oxygen present and the degree of success of germination of the seeds. The first real study to be published in English was done by Mottram in the 1930s. Mottram studied the su...
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Vakalis, F. (2009, March 01). Effects of oxygen on radiation therapy. Retrieved from http://www.slideshare.net/fovak/effects-of-oxygen-on-radiation-therapy
Wouters, B. G., & Brown, J. M. (1997). Cells at intermediate oxygen levels can be more important than the hypoxic fraction in determining tumor response to fractionated radiotherapy. Radiation Research, 147(5), 544. Retrieved from http://www.jstor.org.prx.library.gatech.edu/stable/3579620?seq=4
Yamaguchi, M., & Kashiwakura, I. (2013). Role of reactive oxygen species in the radiation response of human hematopoietic stem/progeny cells. Retrieved from http://ehis.ebscohost.com.prx.library.gatech.edu/eds/pdfviewer/pdfviewer?sid=d059f432-9ed7-40bb-9870-1d5ff0f649c4@sessionmgr4004&vid=5&hid=116
Irradiation in the red/near-infrared spectrum (R/NIR, 630 – 1000 nm) has been recently used as a potential therapeutic strategy to treat different diseases and injuries such as Mitochondrial Disease, Degenerative Eye Diseases, Neurodegenerative Diseases, Cardiovascular Disease and Stroke, Metabolic Diseases (Eells et al., 2003), wound healing, central nervous system injury, and for restless leg syndrome (Fitzgerald et al., 2013).
The concept of tumor heterogeneity being related to the course of the disease and clinical outcome in cancer patients draws additional attention in the era of personalized medicine (1). Current cancer treatment strategies are based on the site of origin of the primary tumor. However, it was shown that tumors developed from distinct cell types differ in their prognosis and response to cytotoxic therapies (2...
The current standard of therapy is resection of the tumor plus radiotherapy and TMZ (E5). Multiple studies performed between 1976 and 1991 have led postoperative radiotherapy to be accepted as standard treatment (L12). The universal dosing schedule for radiotherapy in GBM is fractionated irradiation over 6-7 weeks for a total of 60 gray (Gy) (G7,M13). TMZ is an oral alkylating agent that can be used concomitant with radiotherapy and as an adjuvant. The European Organization for Research and Treatment of Cancer (EORTC) and the National Cancer Institute of Canada (NCIC) organized a study showing that adding TMZ to standard radiotherapy is beneficial to overall survival. This study enrolled 573 patients from 85 institutions and randomly assigned eligible patients to receive either standard radiotherapy alone or radiotherapy plus concomitant and adjuvant TMZ. There was a 37% decrease in relative risk of death and a median increase in survival of 2.5 months in patients treated with TMZ and radiotherapy when compared to radiotherapy alone (P<0.001). There are adverse effects with both RT and chemotherapy, but hematologic toxicities are more likely to occur in patients treated with both TMZ and RT (M13). This study maintained its validity after accounting for recursive partitioning analysis classifications (L12). The current standard dose of TMZ is 75 mg per square meter of body surface area daily during radiotherapy and then a dose of 150-200 mg per square meter of body surface area for 5 days of each 28-day cycle following RT (G7,M13).
Seven to thirteen Artemia (from low nutrition sample) treated twice a day with Tetraselmis species for 3 weeks were placed in a vial with water filling half of the vial. After the vial was kept uncapped for 4 minutes, it was sealed under water with no air bubbles left in the vial. The vial was left for another 4 minutes. O2 concentration was measured using an oxygen meter every 4 minutes for 16 minutes. The length of each Artemia was measured and was used to calculate the length-specific O2 consumption rate. Nine replicates were made.
The Effect of Light Intensity on the Rate of Oxygen Production in a Plant While Photosynthesis is Taking Place
Radiation Effects Research Foundation. (2007). How radiation affects cells. In Basics About Radiation. Retrieved from http://www.rerf.jp/radfx/basickno_e/radcell.htm
who has lost a lot of his or her oxygen cc exchanging ability, due to the
Nowadays, a lot of research teams are trying to develop new ways to treat cancer or to improve the efficacy of already existing treatment strategies. To do this, it is important to understand the differences between tumor tissue and healthy tissue. One of these differences concerns the pH in cancerous environment. In normal cells, intracellular pH is generally around 7,2 and thus lower than the extracellular pH of 7,4. Cancer tissue however shows a reversed pH gradient: the intracellular pH is increased (>7,4) and the extracellular pH is lower than usual (6,7-7,1). This gradient is maintained thanks to changes in the expression and activity of some particular plasma membrane ion pumps and transporters that facilitate the H+ efflux. Due to the increased intracellular pH, cell proliferation and the evasion of apoptosis is possible and the metabolic adaption is facilitated. Moreover, for efficient directed cell migration a higher intracellular pH is even obligatory. The decreased extracellular pH also offers some advantages for the development of the tumor : HCO3—-dependent buffering is limited, extracellular matrix remodeling is promoted and acid-activated proteases are stimulated which makes tumor cell invasion and dissemination easier (Webb e.a. 2011).
Ionizing radiation has enough energy to break chemical bonds and knock electrons out of atoms, some examples of these are x-rays and ultraviolet light rays from the sun. That is why radiation is a way to treat cancer because of the strong energy it has to destroy a cancer cell, actually any cell in the body. That’s the issue with radiation therapy, is it worth the damage? It can damage any cell, whether it is healthy or cancerous, which can cause a major affect in the body later on. Although it sounds scary, there are other types of treatments such as chemotherapy, targeted therapy, immunotherapy, photodynamic therapy, etc.
Radiation is the emission of electromagnetic energy that is given off in the form of high speed particles that cause ionization. During ionization radiation hits and knocks electrons from an atom creating charged ions. Due to the electron being stripped away from the atom this break the chemical bond. Living tissue within the human body is damaged and attempts to repair it but sometimes the damage is beyond repair.
Radiation exposure can affect children as well an children have the risk of being the most harmfully effected by radiation because their body absorbs substances differently also their bodies can or are more likely to get certain kinds of cancers from too much exposure, “they are also closer to the ground, where radioactive fallouts settle.”
Oxygen is widely used in both chronic and acute cases, in emergency medicine, at hospital or by emergency medical services (Nicholson, 2004 ). Just like any other form of medication oxygen is a drug that if used incorrectly could cause potential harm, even death (Luettel, 2010 ). Oxygen is admitted to the patient with chest pain for two main rationales. The first is by increasing arterial oxygen tension, which in opposing causes a decrease to the acute ischemic injury, and thus over time the entire infarct area (Moradk...
Radioisotopes have helped create advanced imaging techniques. Beforehand, X rays could only provide so much information such as broken bones, abnormal growths, and locating foreign objects in the body. Now it is possible to obtain much more information from medical imaging. Not only can this advanced imaging give imaging of tiny structures in the body, but it can also provide details such as cancerous cells and damaged heart tissue from a heart...
Radiology is one of the few so-called “physical-science”-based fields of medicine, making it a challenging and rewarding application of an academic interest in science. It combines advanced knowledge of human physiology with principles of atomic physics and nuclear decay, electricity and magnetism, and both organic and inorg...
During the nineteenth century, Charles Darwin wrote On the Origin of Species (Farah 627). For many years, this book has sparked controversy with a couple of religions. Nevertheless, Darwin’s theory of evolution is taught in many high school biology classes. Another advancement in science was the discovery of X-rays in 1895 by Wilhelm K. Roentgen (Farah 628). This development helped doctors look inside a person without having to make an incision.