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
... Impact of ozone depletion on skin cancers. The Journal of Dermatologic Surgery and Oncology 14: 853-857.
There are essentially three main types of cancer treatments; surgery, chemotherapy, and radiation. Surgery allows doctors to effectively remove tumors from a clear plane. Chemotherapy uses drugs to treat the tumor; but often the drugs affect other healthy cells in the process. Using radiation as a treatment can be either precise or vague. Many health stigmas can come from the vague forms of radiation or conventional radiation therapy. Conventional radiation treats both the unhealthy and healthy cells, therefore exposing healthy cells to harmful radiation (Radiation Oncology, 2011, p.6). When healthy cells are exposed to gamma radiation they are also exposed to ionizing radiation. The ionization can cause “breakage of chemical bonds or oxidization (addition of oxygen atoms)” in a cell; the main impact of this is on a cell’s DNA, if two strands of DNA break it can result in “mutations, chromosome aberrations, ...
Chemotherapy is a method given in which patients are given drugs to kill of cancerous cells. Radiation is another method in which a patient’s body is exposed to high-energy beams to kill cancerous cells. In the study to find an immunotherapy strategy for leukemia, researchers have found that the treatment of leukemia by chemotherapy has achieved success however the issue of minimal residual disease and drug resistance has not been resolved among hematologists. Minimal residual disease is when a small amount of cancer cells remain in the patient during or after treatment when there is no sign of disease. MRD is the major cause of relapse in cancer and leukemia. According to the study, “a high relapse rate due to MRD remains the leading cause of treatment failure and the main cause or mortality.” (Chen et
According to the American Cancer Society, many side effects to radiation therapy occur because normal, healthy cells near the treatment area may become damaged. Temporary side effects may include fatigue, skin changes, hair loss, low blood counts, and eating problems. Longer-term disadvantages to radiation therapy consist of potential damage to the tissue, glands and organs near the vicinity of the tumor, the incapacity to destroy tumor cells that remain undetected on imaging scans, the inability to destroy all cancerous cells in the tumor, infertility, scar tissue growth and more. Unfortunately, when radiation therapy is solely used on particular types of cancers, it may not be entirely successful. This rings true especially for specific cancers that have
The method to use protons such as medical treatment of cancer was proposed by Robert Whilson, who was fade American physicist, in 1946 (McDonald and Fitzek 2010, 257). He argued that the unique physical properties of protons are relevant to utilize this radiation techology in medicine. The principle of the proton beam therapy consists in the appreciable mass of protons than other particles; as a result, the beam slightly broaden and stays focused on the c...
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...
Oxygen is an essential component for cellular metabolic processes. As a result of normal cellular metabolism, oxidative products i.e. oxygen free radicals or reactive oxygen species are produced. In eukaryotic cells energy is generated in mitochondria as a result of aerobic respiration and this oxidative metabolism is responsible for formation of various compounds. Nearly all of these compounds are advantageous but a small proportion could be lethal if produced in higher concentration. During normal conditions small quantities of oxidative products are necessary for certain sub cellular events, including enzyme activation, formation of disulfide bond during the folding of new proteins, signal transduction and gene expression etc. (Yu etal., 2002; Droge, 2002). Oxidative stress can be defined as the excessive production of ROS which are not adequately removed from the body, because of reduced antioxidant defense system or the ROS increases beyond the capacity of antioxidants. The balance between oxidants and antioxidants is vital because oxidative stress can cause oxidative damages to N.A, lipids and proteins. The most important ROS are superoxide anion (O2−), singlet oxygen (O2), hydrogen peroxide (H2O2) and highly reactive hydroxyl radical (OH-). Whereas, antioxidant defense system is responsible to give protection against ROS. These antioxidants can scavenge and destroy ROS. The major antioxidant enzymes are catalase (CAT), superoxide dismutase (SOD) PON ….. and glutathione system (Sies, 1985; Valko et al., 2007; Halliwell and Gutteridge, 1990).
When used correctly, radioisotopes can have a number of benefits, including lifesaving medical procedures. The health risks associated with the use of radioisotopes have been widely documented and debated, and even at one point, suppressed by Congress. However, with the correct precautions these risks can be reduced or even eliminated and radioisotopes will continue to be an integral part of modern day society.
Various data have shown that ROS were involved in the modulation of cell redox state, and redox regulation of protein functions is now accepted as an additional regulatory mechanism of normal cell physiology (Veal et al., 2007). However, excessive production of ROS may lead to oxidative stress, loss of cell function, and cell death by apoptosis or necrosis (Nose, 2000). Excess levels of reactive oxygen and nitrogen species can attack biological molecules such as DNA, protein and phospholipids which led to increase of lipid peroxidation and depletion of the antioxidant enzymes (superoxide dismutase, atalase and glutathione peroxidase) (Sies,1985). PT induced testicular toxicity in rats; this may be due to its oxidative stress. Recent research has revealed that phototherapy is a photodynamic stress. PT can induce oxidative stress and lipid peroxidation, In the study carried out by Ali Aycicek and Ozcan Erel .they showed that vitamin C levels and uric acid, which are well known antioxidants, were significantly lower after phototherapy than before it; in contrast, TOS (total oxidant status), lipidhydroperoxide and OSI (oxidative stress index) levels were significantly higher after phototherapy than before
Researchers over centuries have been examining various cellular aspect of cancer as well as the knowledge of what separates a normal cell from a cancerous cell. The advancement of technology plays a large role in the research development of cancer. It is evident that there are different factors that contribute to the rapid growth of cancer cells. Thu, justifying the complex nature of cancer and the need for continual research needed to be able to have a complete understanding of the disease cancer.
Cancer has become a very common illness world wide for any age but mostly affecting adults. One can get cancer from different places in the body that is why there are so many people with cancer, because of all the different types. Cancer can affect any gender, female or male, and any age. It varies from ovarian cancer to prostate cancer, skin cancer to lukemia. Cancer has been a problem for many years yet we have not found a cure to treat and prevent cancer. If one is affected by cancer there are treatments to help take away this illness affecting their body. This essay is about a specific type of treatment for cancer, radiation therapy. There are different types of forms of particles for radiation, for example, protons and waves like x-rays and visible light. These types of radiations are grouped on how much energy they contain because it can cause different affects. A low type of energy radiation can be radio waves and heat, also known as non-ionizing radiation. 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, wether 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. So if radiation therapy does not sound like the best there are always other options but they do not develop the same results for radiation therapy. Rad...
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.
Although the bystander effect through GJPs may be a problem in metastasis of cancer and also the spread of cellular damage in ischemic conditions, the process may provide ways for therapies in suicide gene therapy, chemotherapy and radiotherapy. These treatments utilize the nature of the bystander effect to deliver either lethal genes, anticancer agents or ionizing radiation to local carcinogenic cells and the cells neighboring them. With the growing understanding of the bystander effect, lower dosages of agents can be used to spare healthy unaffected cells.
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...
Radiation has many benefits for humans, but too much of any type of radiation can be harmful. For example, the sun gives off infrared radiation, or heat, as well as visible light, another type of electromagnetic radiation. These ...