And more. Terry Wayne
Metabolic Solutions Info Series Metabolic Solutions Institute 902-584-3810 Silver The Healthy Metal December 31, 1999 Since ancient times, silver vessels for carrying drinking water, wine, vinegar, and other liquids were known to maintain the freshness of these liquids longer than when placed in any other kind of container. Cyrus the Great, King of Persia (550-529 B.C.), who established a board of health and a medical dispensary for his citizens, had water drawn from a designated stream then "boiled, and very many four-wheeled wagons drawn by mules carry it in silver vessels, following the king whithersoever he goes at any time." [Herodotus, Book I, Para.188, translated by A.D. Godley, Harvard University Press, Cambridge (1946)] . Pliny the Elder, in Natural History (78 A.D.), Libri XXXIII, Part XXXV [as translated by H. Rackham, Volume IX, Harvard University Press, Cambridge (1952)], stated that the slag of silver "... has healing properties as an ingredient in plasters, being extremely effective in causing wounds to close up..." Silver as a Medicinal: In a pharmacopeia published in Rome in 69 B.C., silver nitrate is described as a pharma-cological agent. Likewise, the writings of Geber (702-765 A.D.) describe the use of silver nitrate as a medicinal tool. Avicenna (980 A.D.) employed silver medicinally, including the use of silvered pills and silver filings as a blood purifier. The bluish discoloration of the skin characteristic of excessive use of silver was described by him for the first time. In 1893, Karl W. von Nageli, in the German journal Nature (Naturforschung Gesellschaft, Vol. 33, p. 174, 1893) reported considerable change in the bacteria's cell structure when killed by AgNO 3 in dilutions at 10 ppm in 3 to 4 minutes. Saxl, Theil, Wold, and others following his lead also found that small amounts of silver were lethal to bacteria. In the late nineteenth century, the German obstetrician F. Crede observed that 20 to 79% of the children in institutions of the blind were there as the result of exposure to maternal venereal disease (ophthalmia neonatorum). He reported that 10% of the infants born at the University Clinic of Leipzig had the disease. In 1893, drawing on his knowledge of the medicinal properties of silver, Crede introduced the installation of 1 to 2% silver nitrate solution into the eyes of newborns. There was an immediate decrease in the incidence of infant blindness (gonoccoal opthalmia) from 10% to 0.2%. As a result, the Crede prophylaxis became obligatory during the first half of this century in the USA and most European countries. Even since the appearance of antibiotics in the 1940s, Crede's prophylaxis has continued and is still regulated by statutes in many countries throughout the world. Silver in Everyday Life: Silver constitutes about 0.07 parts per million in the earth's crust. In sea water, the concentration may be as high as 0.000,002 parts per million. Food stuffs including dairy products tend to accumulate metals such as silver. In a normal diet, a person may ingest 30 to 40 parts per million (30 to 40 micrograms) per day. Mushrooms, for example, may boost silver consumption up to between 200 to 300 micrograms per day. Studies have shown that 10% of orally-ingested silver enters into the systemic circulation. Of that 10%, up to 98% is gathered up by metallothioneins. These ubiquitous proteins, found in all vertebrates and invertebrates, act to transport, store, and detoxify essential and nonessential trace metals. They agglomerate (chelate) heavy metals such as cadmium, lead, mercury, copper, and silver to convey them from the body. As a consequence, very little free silver actually enters the blood stream. Enter Silver Colloids: Albert Barnes and a Prussian chemist named Hille discovered, in 1901, a method of preparing a silver protein colloid by combining a vegetable product with a silver compound. The product was a dark liquid - a true colloid - highly light sensitive requiring packaging in dark glass bottles. Patented as Argyrol, the product was the only non-toxic antibiotic on the market at the time. It was widely prescribed for over 50 years because synthetic antibiotics often produced major allergenic reactions. Crede also introduced colloidal silver into medicine with the idea that it would possess the germicidal properties of silver, and being non-toxic, might be used internally for the control of various bacterial infections. Silver colloids found extensive use in the treatment of septicemia, rheumatic fever, gonorrheal arthritis, diphtheria, cerebro-spinal meningitis, and other infectious diseases. [The Dispensatory of the United States of America, 22nd Edition, J.B. Lippincott Co., Philadelphia (1937)] "The introduction of the metallic colloids into medicine constitutes a new departure in therapeutics, the significance of which does not appear as yet to be generally recognized," said B.G. Duhamel, MD, in "Electric Metallic Colloids and Their Therapeutical Applications," The Lancet, January 13, 1912, p. 89-90. He describes reports of the successful use of silver colloids in many applications, for example: "L'Argent Colloidal dans les Affections des Voies Urinaires," Dr. H. Hamonic, Transactions of the Association Francais d'Urologie, October 1907; and "Electrargol dans l'Infection Puerperale," Dr. J.T. Alonzo, Ravista de Medicina y Cirurgia Practice, July 21, 1910. In March 1911, the Henry Crookes Laboratories introduced "collosol argentum." Technical journals reported the success of this silver colloid for the treatment of difficult diseases. For example: "Collosol Argentum and Its Opthalmic Uses," A. Legge Roe, The Institute Medical Journal, January 16, 1915, p. 104; and "A Case of Puerperal Septicaemia Successfully Treated with Intravenous Injections of Collosol Argentum," T.H. Sanderson-Wells, MD, The Lancet, February 16, 1916, p. 258. An invited paper, "The Therapeutic Effects of Colloidal Preparations," by Malcolm Morris that appeared in The British Medical Journal, May 12, 1917, reported that collosol silver rapidly subdues inflammation and promotes healing of lesions. Enter Antibiotics: The discovery by G. Domagk, in 1932, of the antimicrobial activity of the azo dye Prontosil opened the era of synthetic therapeutic drugs. The active component of Prontosil, paminobenzenesulfonamide, is commonly known as sulfanilamide. Of its many thousands of derivatives, some 20 are still being administered. Penicillin was discovered by A. Fleming in 1928, but it was not until the enormous research effort required to develop its large-scale production, which was provided during World War II, that it entered widespread use. The pharmaceutical research then established led to the preparation of thousands of synthetic antibiotics, including cephlosporin C, streptomycin, tetracycline, polymyxin, gentamycin, chloramphenol, etc. The synthetic antibiotics are selectively toxic, damaging specific types of cells, while not others. They are not normally harmful to human cells because mammalian cells have different wall structures from bacteria. The action of antibiotics may be by (1) affecting the cell wall causing loss of viability, (2) affecting the barrier function of the cell membrane leading to leakage of the cell's components, (3) interfering with protein biosynthesis, (4) interfering with the nucleic acid biosynthesis, or (5) blocking steps in intermediary metabolism. The action of the sulfa drugs, for example, blocks specific steps in the metabolism of bacteria, preventing viability. The first sulfa drug was sulfanilamide, which was successively replaced by further formulations that provided greater activity, arriving finally at sulfadiazine which is more easily tolerated and has fewer side effects. Synthetic antibiotic drugs replaced silver ions and silver compounds because of their faster kill rate specificity. Resistance to Antibiotics by Bacteria: After prolonged use, the therapeutic value of the synthetic antibiotics has declined because of the emergence of resistant organisms. The development of resistance varies with the organism and the antibiotic and may be due to spontaneous mutation of the infecting organism, the acquisition of pieces of DNA from other organisms so as to organize resistance, or by the proliferation of preexisting resistant-related organisms which take over the field. The fact that silver has been used successfully for controlling bacteria over millennia is evidence of a more stable antibiotic resistance. Biological Action of Silver: The mechanisms by which silver inactivates bacteria, viruses and fungi is not clear. Primarily, silver reacts with the bacterium's cell wall. The cell wall of bacteria is a structure of proteins connected by amino acids to provide it with mechanical strength and stability. The structural proteins are called peptidoglycans. Silver reacts with the exposed peptidoglycans, blocking their ability to transfer oxygen (energy) into the cell, thus inactivating the bacteria, which results in expiration. If the silver ions are chemically removed from the cell immediately, the function of the bacteria may be restored. Since mammalian cells have an entirely different coating on their cells (no peptidoglycans), silver has no effect upon those cells. This action of silver is not disease specific, like the synthetic antibiotics, but cell-structure specific. Any cell that does not possess a chemically resistant wall is available to action by silver. This would include all bacteria and other organisms without cell walls, for example, the extracellular viruses. The idea of combining silver with an antibiotic to combine the best features of both was that of Charles L. Fox, M.D., Columbia University School of Physicians & Surgeons, New York. His combination of silver with sulfadiazine produced a mild, easily applied drug at least 50 times more active than sulfadiazine alone. Introduced to the market in 1968 as Silvadene R , it has proven to be the most efficacious topical (surface application) compound for controlling bacteria in open wounds of any size. The combination inhibits infection over extended periods of time allowing dermal structures to reconstruct themselves naturally, unimpeded by bacteria. The complete restoration of wound areas proceeds naturally and painlessly, avoiding the need for skin grafts. All the pre-existing functions of the damaged area are restored to their original fully functional state by natural reconstruction. Silver sulfadiazine has become the treatment of choice for traumatic injury such as burn wounds. Hundreds of thousands of soldiers and civilians have had their burn wounds recover and the injured areas restored without unsightly skin by the use of this compound. It is marketed by Marion Merrell Dow as Silvadene R (available by prescription only). Extensive studies with silver sulfadiazine have proven its efficacy against a wide variety of bacteria, extracellular viruses, fungi, and protozoas. [M.S. Wysor, Antibiotics, Springer Verlag, Germany (1983)] Natural Control of Silver in the Body: Studies have shown that oral doses and injections of silver in the body result in rapid excretion by the bowels (~70%) and in the urine (~25%). Massive ingestion of silver may result in discoloration of the skin, but this has never been a fatal condition. Evidence exists that the presence of silver ions in a wound site stimulates nerve and epidermis reconstruction. The removal of silver and other heavy metals is the function of the metallothioneins. These ubiquitous proteins are found in all vertebrates and invertebrates and act to transport, store, and detoxify essential and nonessential trace metals. The metallothioneins chelate or agglomerate heavy metals and convey them from the body. Their action can be overwhelmed by ingestion of excessive amounts of heavy metals. In the case of silver, excessive amounts may eventually deposit in the skin, giving it a gray color. This deposit is called argyria and cannot be removed. Silver, being a highly conductive metal, has been shown to have a deleterious effect in the presence of nerve cells. While heavy metals are blocked from the nervous system and the brain by the blood-brain barrier by a membrane whose purpose is to filter out heavy metals, certain stresses, such as hypoxemia (the dangerously low level of oxygen in the blood that occurs to some climbers at very high altitudes), may weaken this barrier. Silver also reacts with the cells in fish gills that transport oxygen to block their ingestion of oxygen. The low concentrations of silver used in swimming pools, less that 50 parts per billion, would be diluted considerably below that intensity when drained into sanitary or storm sewers. Studies with rainbow trout exposed to a silver ion concentration of 10 ppb exhibited negligible disturbance. [C.M. Wood, Aquatic Toxicology, 35 93-109 (1996)] Increased Interest in Silver as An Antibiotic: It has long been recognized that increased use of synthetic antibiotics in hospitals is associated with an increased resistance by bacteria. This has driven physicians to seek alternatives to protect their patients. It has been found that persistent organisms such as Legionella pneumophila have proliferated in the dead ends and stagnant areas of hospital hot water systems and in hot and warm water storage tanks. The long-used purging systems of charging with high concentrations of chlorine or by flushing with scalding water have proven unsatisfactory. High concentrations of chlorine are extremely corrosive to piping and equipment and do not kill many organisms including L. pneumophila, and provide no residual protection to the system. Scald-water flushing is labor intensive, extremely time consuming, and does not reach into dead-end piping. A study in North America and England revealed that in-building water distribution systems are the major reservoirs for hospital-acquired Legionnaires' disease. As a result, more than 125 leading hospitals in the US have installed silver/copper ionization systems, which have been successful in eradicating L. pneumophila from their hot water systems. Silver/copper ion sanitation systems which carry the approval of the Environmental Protection Agency and/or the Food & Drug Administration, and certified for performance by the National Sanitation Institute/ International, Ann Arbor, MI, are available in the marketplace. The Silver Colloid Revisited: A useful silver colloid is one whose silver particles are in the submicron range (10 -6 meters). A properly prepared submicron colloidal silver will not separate out in a high-speed centrifuge. The smaller the particles are, the longer they retain their electric charge and remain suspended as a colloid. Since the submicron region is smaller than the size of bacteria, the submicron size is optimal for multiple contact with the cells of bacteria. Larger sized colloids tend to fall out of suspension. Metallic silver is known to dissolve in water in an amount of about 10 ppb (10 -5 grams per liter), which is toxic to E. coli and Bacillus typhosus [G.V. James, Water Treatment, 4th Ed., CRC Press, Cleveland, OH, p. 38 (1971)]. Thus, the sanitation action of silver colloids (submicron particles of solid silver) is similar to that of the silver ions used to sanitize hundreds of thousands of swimming pools worldwide. The optimal concentration of a silver colloid appears to be about 10-40 ppm. Concentrations less than 10 ppm are less effective and greater concentrations than 40 ppm waste the colloid. If the water is measurably pure and the particles are in the submicron range, no additives are required to maintain the colloid; furthermore, additives reduce purity. The pH of silver colloids should fall between 6.5 and 8 because increasing amounts of silver oxide will appear as the pH of the solution falls below 6.5 and silver oxide is a less effective bactericide than pure silver. Silver oxides can be removed by filtration. If water is double distilled oxygen-free water having a pH 7, silver oxides will not be produced. Distilled water may be flushed with helium to remove excess oxygen without adding impurities. Total dissolved solids must be zero. Voltage and amperage for colloid generation must be carefully controlled. The silver colloid with its small size will dissolve at a greater rate than a larger mass of solid silver, thus providing a satisfactory level of the sanitary effects of the silver without the caustic effects of silver nitrate. Because the action of silver is not disease specific, like the synthetic antibiotics, but is cellular structure specific, the use of silver colloids as a general bactericidal agent is justified. Can We See How Silver Works? A simple laboratory experiment showing how effective solid silver is in sanitizing its environs is to place a silver coin in agar (a bacterial culture media) and expose it to the atmosphere. After several hours, the agar is a mass of bacterial growth, but in an area surrounding the silver coin, there is no growth, showing that enough silver has dissolved from the solid silver to sanitize the surrounding area. Recent Trials with Silver Colloids: Field trials using silver colloids against cow mastitis have recently been conducted with several herds in a few Midwestern states. All mastitis-infected cows were inoculated with 5 to 15 ppm silver colloid. At 5 ppm, four of six strains of bacteria were eliminated. However, E. coli was resistant and required 15 ppm for complete elimination. Following treatment, within four milkings the presence of silver was undetectable. The alternative is expensive bactericides which may or may not be totally flushed out of udders. Studies are continuing to develop an FDA approval for use with commercial milk-producing cows. Metabolic Solutions Info Report Metabolic Solutions Institute 902-584-3810 Toxicity Summary for SILVER http://risk.lsd.ornl.gov/tox/profiles/silver_f_V1.shtml 2. METABOLISM AND DISPOSITION 2.1. ABSORPTION Studies in humans and animals indicate that silver compounds are absorbed via the oral and inhalation routes of exposure, with some absorption occurring through both intact and damaged skin (ATSDR, 1990). East et al. (1980) reported that a patient with argyria (gray or blue-gray discoloration of the skin) absorbed approximately 18% of a single dose of orally administered silver. Generalized argyria in a woman who repeatedly applied a silver nitrate solution to her gums indicates absorption across the oral mucosa (Marshall and Schneider, 1977). Absorption from the lung was documented in a case of accidental exposure to radiolabeled silver metal dust (Newton and Holmes, 1966). Following intratracheal administration to beagle dogs, the absorption of metallic silver particles appears to be extensive. Phalen and Morrow (1973) estimated that up to 90% of silver (mean aerodynamic diameter = 0.5 µm) deposited in the lungs of dogs was absorbed into the systemic circulation 6 hours after exposure. In humans, less than 1% of dermally applied silver compounds are absorbed through the skin. (Snyder et al., 1975) 2.2. DISTRIBUTION Silver has been detected in 50% of the samples of 29 human tissues, but at lower levels than other trace elements (U.S. EPA, 1985). Silver has no known physiological function in man, but its accumulation leads to argyria when the body burden is 1 g (Stokinger, 1981). Granular deposits that contain silver have been observed in both pigmented and unpigmented skin of silver-exposed humans and animals. Once absorbed, orally-administered silver undergoes a first-pass effect through the liver, resulting in excretion into the bile, and thereby reducing the systemic distribution to tissues (ATSDR, 1990). Following ingestion of silver nitrate and silver chloride, silver was distributed widely in tissues of rats, with high concentrations seen in the tissues of the reticuloendothelial system (liver, spleen, bone marrow, lymph nodes, skin, and kidney) (Olcott, 1948). Silver was confined mainly to the liver of a worker who had accidentally inhaled radiolabeled silver metal; a biological half-life of 52 days was estimated (Newton and Holmes, 1966). Six hours after intratracheal administration of metallic silver to dogs, 96.9, 2.4, and 0.35% of the initially deposited dose was detected in the lungs, liver, and blood, respectively. The remaining silver was detected in the gall bladder and bile, intestines, and stomach. After 225 days, the distribution in tissue type was similar, with most of the silver found in the liver (Phalen and Morrow, 1976). 2.3. METABOLISM ATSDR (1990) reports that the deposition of silver in tissues is the result of the precipitation of insoluble silver salts, such as silver chloride and silver phosphate. These insoluble silver salts are then transformed into soluble silver sulfide albuminates, to bind or to form complexes with amino or carboxyl groups in RNA, DNA, and proteins, or to be reduced by ascorbic acid or catecholamines. The skin discoloration of humans with argyria may be caused by a photoreduction of silver chloride to metallic silver. The metallic silver is then oxidized by tissue, subsequently forming black silver sulfide. 2.4. EXCRETION Following oral or inhalation exposure to silver compounds, humans excrete silver primarily in the feces and only very minor amounts in the urine (East et al., 1980; Newton and Holmes, 1966). In rats and mice, the cumulative recovery of silver in the feces was 98-99% on the second day after oral exposure to silver; monkeys excreted 94% (U.S. EPA, 1985). Dogs excreted approximately 90% of an inhaled dose of metallic silver particles in the feces within 30 days of exposure (Phalen and Morrow, 1973). Metabolic Solutions Info Report Metabolic Solutions Institute 902-584-3810 Growth Reported in Silver-based Systems for Swimming Pool Sanitization July 31, 1997 Silver-based mechanisms for keeping swimming pools sanitized are gaining widespread popularity among pool owners preoccupied with the mounting health hazards of chlorine. Recently, chlorine has been shown to produce by-products linked to cancer in laboratory animals, prompting an immediate US government review. The purification method named the number one alternative to chlorine, based on research conducted by Swimming Pool and Spa Age magazine, is a silver catalyst system that has the capacity to instantly destroy bacteria and viruses. Manufactured by Fountainhead Technologies, based in Providence, R.I., the Nature2 system deposits silver microcrystals on the inside of a flow-through cartridge, which feeds oxygen into the water flow. The oxidized silver then destroys bacteria, viruses and organic matter. Tests performed by the U.S. Environmental Protection Agency (EPA) at the University of Arizona, for example, found that the cartridge reduced the presence of E. coli in water by 99.96 percent within five seconds. "We're seeing double-digit growth at Fountainhead," said James Palmer, vice president of sales. "We expect to have our system in more than 100,000 pools by the end of the year," up from 10,000 units just four years ago, he said. "There is great interest in alternatives to chlorine, especially among pool builders and retail stores." Apart from Fountainhead's relatively new catalyst system, silver-copper ion systems have sanitized tens of thousands of swimming pools worldwide for several decades. Silver ions have the capacity to inactivate organisms including Bacillus typhosus, Legionella pneumophila and E. coli. Copper ions, also generated in this system, are algaecides that eliminate unwanted growth in the pool and supplement silver in controlling pathogens such as the polio virus. While silver has been used for centuries to purify water, modern ionization technology was developed by the National Aeronautic and Space Administration (NASA) in the early days of the space program as a lightweight method of purifying recycled water on spaceships. The technology works by producing positively charged ions that attack and destroy the negatively charged cells of organisms like bacteria and algae. At least 20 companies in the United States offer ionization systems. And while all systems use varying amounts of silver, estimates given by several manufacturers range from one ounce per unit to five ounces per unit annually depending upon the size of the pool, the unit and usage. According to the UK-based Institute of Water Ionisation Technologies, a typical residential swimming pool using copper/silver alloy electrodes would consume approximately 1.3 ounces of silver during a summer season. " I can tell you the market is growing rapidly," said a representative of Superior Aqua Enterprises of Sarasota, FL., a manufacturer of ionizers for pools and spas as well as hot water systems, cooling towers and marine mammal tanks. A representative of Caribbean Clear of Hilton Head, S.C., agrees the market is expanding. "Our sales are growing primarily because people are increasingly wary of chemicals such as chlorine. They're tired of the effects of chlorine on the body and of hearing about the hazards of chemicals." A third and new silver technology now on the market employs polyvalent silver oxide. Several years ago, x-ray analysis showed silver oxide to contain silver atoms with two different charges: half of the silver ions had a single charge, such as those found in silver-ion systems, and the other half had a triple charge. Because it is difficult to oxidize silver, the energy required to convert the metal into this form is stored in the silver oxide, and when it is dispersed in a pool, bacteria and viruses are destroyed by the stored energy which is discharged on contact. The N. Jonas & Co. in Bensalem, PA., owners of the patented use of silver oxide as a swimming pool sanitation agent, obtained EPA registration for its use in domestic swimming pools just last year. "We sold 26,000 units in our first year," said Al Pastore, the company's technical director. "Each of our units uses 1.3 ounces of silver, for a total silver usage in 1996 of 35,000 ounces." While there are no specific market statistics on total numbers of swimming pools that use silver-based sanitizers, experts throughout the industry agree these technologies are making significant inroads into the long-standing chlorine market. According to the most recent research on the swimming pool industry, published in 1993 by the National Spa and Pool Institute (NSPI), 6.6 million individuals in the United States own pools, 3.4 million of which are inground and 3.2 million are aboveground. NSPI estimates that approximately 160,000 inground pools are built annually in the United States, in addition to about 475,000 aboveground pools. Not surprisingly, California, Florida, Texas and Arizona are the states with the largest number of inground pools, followed by New York, New Jersey, Pennsylvania, Massachusetts, Ohio and Georgia. The top three states for aboveground pool ownership are New York, Pennsylvania and California. In Europe, France and Spain have the highest numbers of swimming pools. According to Roseland Hydronics PLC, sales of swimming pool ionizers outside the U.S. are in the range of 100,000 to 120,000 annually. South Africa and South America have seen strong sales growth in this area, with South Africa representing approximately 50 percent of total sales outside of the U.S. According to NSPI, pool owners in the United States today can be described as "average Americans, living in average American households. They are married, middle-aged, average in income and education and have children, very often the children are young and living at home. Pool owners own their own homes and more often than not, live in a suburban area." "Silver's use in swimming pool sanitation is growing because of the many advantages these systems offer," said Paul Bateman, The Silver Institute's executive director. "Silver has long been known as a healthful metal and these systems are less expensive than chlorine and other chemicals," he added. "Silver does not evaporate from the water leaving the pool unprotected and does not stain the skin or bleach clothing." __________________________________________________ Do You Yahoo!? Yahoo! Photos - 35mm Quality Prints, Now Get 15 Free! http://photos.yahoo.com/ -- 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: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. 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