Cell death restrains the superfluity of physiological processes such as embryogenesis, post-embryonic development (Penaloza et al, 2006) and tissue homeostasis and abrogating cell death provokes various diseases such as autoimmune diseases and cancers. (Galluzzi, Maiuri et al. 2007) In the long time of cell death related studies researcher have found dozens of methods to study the death related parameters but none of these method fulfill the requirement. NCCD (Nomenclature Committee on Cell Death) assigned some features for a cell known to be dead which includes. 1) Loss of plasma membrane integrity. 2) Complete destruction of the cell as well as its nucleus. 3) Engulfment of its fractions by neighboring macrophages in vivo. Cell death can be divided into various categories based on morphological appearance (apoptosis, autophagy, necrosis and mitosis associated cell death), enzymatic (with and without involving crucial enzymes such as nucleases, and proteases such as caspases or cathepsins), functional prospects (Physiological or pathological, programmed or accidental) or finally immunologic or non-immunogenic. (Kroemer, Galluzzi et al. 2009).
It was earlier believed that the caspases dependent apoptosis governs all regulated cell death in mammalian cells (Fuchs and Steller, 2011; Thompson, 1995). But this perspective has recently changed after Christofferson et al and others have comprehended the non-apoptotic cell death pathway which includes apoptosis inducing factor 1 (AIF1)-dependent parthanatos, caspase-1-dependent pyroptosis, poly(ADP-ribose) polymerase-1 (PARP-1) and receptor interacting protein kinase 1 (RIPK1)- dependent necroptosis (Bergsbaken et al., 2009; Wang et al.,2009; Christofferson and Yuan, 2010). Yang et al h...
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...r cell proliferation and survival via high NADPH production and low ROS level (DeNicola, G.M. et al., 2011; Son, J. et al., 2013; Maddocks, O.D. et al., 2013). Glutathione homeostasis may be regulated via NADPH and so either glutathione reduction or high oxidative stress could induce senescence or cell death to a cancer cell (Trachootham D., et al., 2009). Small molecules targeting glutathione antioxidant network such as glutathione itself and glutathione peroxidase e.g. parthenolide (Pei, S. et al., 2013) and ethylisocyanate (Trachootham D., et al., 2006) catalytic subunit of glutamate cysteine ligase and system XC-- e.g. sulfasalazine and Errastin glutathione S-transferase pi 1 and carbonyl reductase e.g. piperlongumine (Raj, L. et al., 2011) could be promising tool to combat cancer stem cell populations which are resistant to radiotherapy induced apoptosis.
The use of Henrietta Lacks cells has led to many scientific breakthroughs, e.g., the cure to polio, cloning, and the human genome project. Henrietta Lacks was an African American woman who died of cervical cancer in 1951. These cells underwent a mutation that caused them to become immortal, meaning that they continue to divide since her death in 1951 to this very day. However, her cells raise an ethical question, because before she died she did not give consent for scientists to use her cells and after she died they did not tell her family that they were using them. This has been an ongoing controversy because the cells have been so beneficial for society, but they are derived from shady procedures. The reason way Henrietta’s cells, HeLa cells, didn’t undergo apoptosis was that they were cancerous cells that replicated indefinitely and these cells were modified to be even more resistant due to other diseases Ms. Lacks had.
In The Immortal Life of Henrietta Lacks, multiple cell research studies involving Henrietta’s cells are described. Author Rebecca Skloot writes about Henrietta Lacks’ journey through her cervical cancer and how her cells changed the lives of millions long after her death. Skloot relates the history of cell research, including those studies which were successful and those that were not so successful. It is necessary for the author to include the achievements and disturbing practices of scientists throughout this history to inform readers and focus on the way Henrietta’s cells were used. Truth always matters to readers and Henrietta’s family deserves the truth.
The cancer stem cell theory hypothesizes that tumors or cancers arise from mutations or epigenetic changes in normal stem cells. These mutated or genetically altered stem cells possess the properties of the normal stem cells such as the ability to self-renew, differentiate into any type of body cell, and resist apoptosis. Hence, the cancer stem cells (CSC) are named so. It is also suggested that because of the above-mentioned properties of the cancer stem cells, the current anti-cancer therapies are not entirely successful (Gil et al, 2008). Despite surgery and other therapies, even if very few of these cancer stem cells survive, they can continue to act as a source for more tumors, even though the therapies eliminate all visible signs of cancer.
Chemotherapy is the treatment of a tumor with chemical agents to reduce mass or eradicate a tumor completely. There are certain mechanisms by which chemotherapy inhibits cancer. The first mechanism is cell death by cytotoxicity. Some chemical agents in certain amounts are toxic to cells. The cells die due to the toxic...
Li, Y., Wicha, M. S., Schwartz, S. J., & Sun, D. (2011, February 4). Implications of Cancer Stem Cell Theory for Cancer Chemoprevention by Natural Dietary Compounds. Retrieved December 12, 2013, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248810/
An idea first brought to the attention of the world back in the 1960’s when researchers first noted that the cell could destroy its own contents by a matter of enclosure within the membrane. (1) This lead to the formation of vesicles that were efficiently transported to a recycling component called the lysosome, for degradation. The term autophagy simply means "self-eating”. Scientifically, the term accounts for “a normal physiological process that deals with the destruction of cells in the body”. (2) Due to the complexity of the phenomenon, little advances had been made until a series of experiments were conducted in the early 1990’s. Yoshinori Ohsumi; a Japanese cell biologist born in 1945, conducted an experiment using the test subject of yeast, which led him to identify the critical genes for autophagy. Through further studies, he noted the underlying correlation between autophagy mechanisms used in yeast and the machinery used in our cells. Ohsumi’s new discoveries created the path in understanding the critical importance of autophagy in many
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).
The cell cycle is the process by which cells progress and divide. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates it’s DNA and divides, these are called proto-oncogenes. A proto-oncogene is a normal gene that could become an oncogene due to mutations. This process has mechanisms to ensure that errors are corrected, if they are not, the cells commit suicide (apoptosis). This process is tightly regulated by the genes within a cell’s nucleus. In cancer, as a result of genetic mutations, this process malfunctions, resulting in uncontrolled cell proliferation. Mutations in proto-oncogene or in a tumour suppressor gene allow a cancerous cell to grow and divide without the normal control imposed by the cell cycle. A change in the DNA sequence of the proto-oncogene gives rise to an oncogene, which
Brain death occurs when there is a loss of all brain and brain stem function due to damaged brain cells. It is often termed as an irreversible coma as the damaged cells cannot regenerate themselves and a patient is stuck in a coma-like state. (Wilson and Christensen, 2014)
Pawar, A. K. (2009). the diagnosis of brain death. Retrieved january 29, 2014, from ncbi.nlm.nih.gov: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2772257/
It has been found that the decomposition process is best divided into five stages: fresh stage, bloated stage, decay stage, post-decay stage, and remains. The fresh stage starts the moment the individual died and lasts until bloating can be observed. The bloated stage is usually within two to seven days after death. Putrefaction begins at this stage and the gases produced from bacteria cause...
John L McIntosh. (2003) . Handbook of Death and Dying. Volume 1: The Presence of Death. Thousand Oaks, CA: Sage Reference.
Ajay Kumar Goila and Mridula Pawar (2009). The Diagnosis of Brain Death. [ONLINE] Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2772257/. [Last Accessed 11 February 2014].
One thing that we often hear is that “death is just a part of life.” So often in our day and age do we hear people utter these words. However, death is far more significant and impactful than some would allege. True death is not merely a time when we cease to exist; it is an entombment, a mindset in which we are dead to this world. Throughout our lives, it is true that we can all be dead in one way or another, but it does not have to be that way. When we have our eyes opened to what death actually is, it is far easier to grasp what the true meaning of life is, and to embrace it. Often, we will come across individuals who are enveloped in death and others who are immersed in true life. The shadow of death and entombment lies upon some, encompassing
Frederick, Calvin J. "Death and Dying." Microsoft® Encarta® 98 Encyclopedia. © 1993-1997: Microsoft Corporation. CD-ROM.