Ivan Anderson wrote: > > Bob Lee wrote, in part: > > > Cancer cells require much oxygen, more than a cell under > control. > > Excess oxygen in the body has been pointed out as a cause of > promoting > > cancer development. The excess oxygen is usually in the form of > oxygen > > radicals such as O3 and H2O2, both of which have been > identified as > > *promoters* of cancers. Cancer cells even turn on genes that > cause extra > > blood capillaries to develop and supply them, the cancer cells, > with > > more oxygen. > > Cancer cell physiology is very interesting and surprising. Any > > interest? > > Bob, > Thankyou. > > The plant - cancer cell analogy is obviously ill-founded, having > read your description. > And while I can find evidence to support your statement above I > also find evidence that tumors exist in and have existing in > them, an acidic and barely aerobic environment, and that they do > not rely to any great extent on respiration, but rather on the > fermentation of glucose. > > Can both assertions be correct? > > Regards - Ivan.
Hi Ivan and Listers, Great question Ivan. Lets look into the area of fermentation, and other things. We know that *aerobic* means the use and need for oxygen. Also that *anaerobic* means NOT using and needing oxygen. Most plants and animals are aerobic, oxygen users. There are some bacteria that do not use oxygen but can live in an oxygen environment. There are bacteria that will die in an oxygen environment. They don`t want oxygen anywhere near them. We humans are *aerobic* MOST of the time, not always. Our cells can switch over to *anaerobic* if the need arises. If you fall into a freezing body of water and sink to the bottom, and then are rescued and revived everyone goes around saying it was a miracle. No such thing. The body was in the anaerobic mode. Say you are running so hard you can`t take another step and collapse on the ground. Your muscle cells are operating in the anaerobic mode for lack of oxygen. You have a heart attack and survive it, most people do survive at least one or more. They survived because the body was in the anaerobic mode. Our body is an amazing thing. Long ago Pasteur (we all know him) did a lot of work with fermentation. He knew that fermentation resulted in the formation of alcohols and CO2, or of acids. He knew that it was caused by microorganisms growing in anaerobic environments, little or no oxygen. This was contrary to the requirments of most organisms with which Pasteur was famililiar. Many years were to pass before the details of *biologic combustion* were worked out. Right now we will talk about *anaerobic respiration* (fermentation). It is thought that anaerobic respiration was utilized by the first organisms on the early earth, which lacked an oxygen atmosphere. Thus anaerobic respiration, or fermentation, would have been the only way energy could have been released for metabolism. When compared with aerobic respiration, fermentation is very inefficient. It yields only about 5% of the total potential energy from a molecule of *glucose* (C6H12O6). Thus, fermentation is an incomplete form of respiration. This is explaned by the fact that the glucose molecule is only partially broken down in the process. Most of the total enery remains in the end products of alcohol or acid. In aerobic respiration the breakdown is complete, giving end products of water and carbon dioxide. Not complex substances such as alcohol and organic acids. Both anaerobic and aerobic respiration release energy from glucose, and are both examples of biological combustion. What makes them different? In both cases a glucose molecule is split and oxidized to make two molecules of *pyruvic acid*, and in the process there is a net gain of two molecules of ATP ( the cells power source). In respiration involving free oxygen, the pyruvic acid is completely oxidized; all its hydrogen atoms are removed and the electrons pass down the transport chain and are combined with oxygen, forming water. These are the steps that generate most of the ATP of the cell. In fermentation, however, the steps are different after the formation of pyruvic acid. Carbon dioxide is removed from the pyruvic acid molecule and is released, leaving CH3-CHO, or *acetaldehyde*. Depending on the species of microorganism, the acetaldehyde is converted into ethyl alcohol, acetic acid, lactic acid or other products. There are two classes of anaerobic organisms, some can utilize free oxygen and respire like other air respirators. They possess the equivalent of *mitochondria* with the full electron transport, just like our body cells. When deprived of oxygen these organisms can get along on the preliminary stages of the breakdown of glucose, fermetation. Each of our body cells contain many thousands of bacteria doing all kinds of things that are neccessary for our cells to live,including bacteria which will become active and start fermenting and producing energy for our cells when the oxygen intake becomes to low. They are working on glucose that is already stored in the cell. Thats why you get really hungry after exercising, the glucose is used up and the body needs to get more. The other class of anaerobes cannot ever use free oxygen, in fact it usually kills them. Lets look at reaction pathways a little more for a better understanding. In plant and animal cells neither the citric acid cycle nor the electron transport system can operate without oxygen. Oxygen is the final hydrogen and electron acceptor in the electron transport chain. When oxygen is not available, the last *cytochrome* in the chain cannot transfer its electrons. The preceding electron acceptor then has no acceptor to give its hydrogen electrons to and so on down the chain. No further ATP is produced, energy production stops (like in dead). Our cells, and the symbiotic bacteria in them, can carry on with anaerobic respiration in the absence of oxygen. This is a very low level of ATP production and can just barely maintain the live of the cell (body). In fermentation the ATP is generated by a process that utilizes organic compounds both as donors and receptors of electrons. Yeast cells convert pyruvate to ethyl alcohol, if we had those enzymes in us we could get drunk by running up several flights of stairs. Animal cells, most notably muscle cells, can release energy anaerobically for a time by producing lactate. The hydrogen atoms removed from the glucose molecule during glycolysis are transfered to pyruvate, the enzyme lactate dehydrogenase present in these cells converts pyruvate to lactate. This occurs during strenuous exercise when the amount of oxygen delivered to the muscle cells is insufficient to keep pace with the rapid rate of glycolsis. Lactate *acidifies* the blood, as lactate accumulates in the muscle cells it lowers the pH and contributes to *muscle fatigue*. The inefficiency of anaerobic processes (fermentation) necessitates the use of a large amount of fuel. To perform the same amount of work, a cell functioning anaerobically must consume up to twenty (20) times as much glucose or other carbohydrates as an aerobic cell. For this reason the muscle cells usually store large quantities of glucose in the form of glycogen. A cancer cell relying on anaerobic, fermenting, respiration will not grow; being barely able to maintain itself, and may even appear to be in remission. We starve a cancer cell by denying it glucose and oxygen. Puting extra oxygen into the body helps the cancer cell, not what we really want to do. New drugs are being tried that cause the blood capillaries around a cancer to disappear and cause a shortage of oxygen to the cancer. Bless You Bob Lee -- oozing on the muggy shore of the gulf coast l...@fbtc.net -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour <mdev...@id.net>
