Awakenings to the pathogenicity of urease and the requirement for continuous long term therapy.
Urease is an enzyme found in plants and bacteria, but not mammals. It catalyzes the conversion of urea to carbon dioxide and ammonia. Ammonia shortens the life span of cells; and higher concentrations cause tissue necrosis and cytolysis. Twenty percent of total body urea is converted to ammonia by bacterial urease in the colon. Small injections of urease immunize animals by producing antiurease, a gamma globulin, which inactivates urease. Immunization eliminates the colonic conversion of urea to ammonia. Injection of urease produces ammonia intoxication making immunization hazardous. Although previously impossible, a non enzymatic urease antigen was synthesized by covalently bonding jack bean urease with glutaraldehyde. This antigen stimulated the production of antiurease that inactivates native urease. Helicobacter pylori, a potent urease producer, has been implicated in peptic ulcer, gastritis and other inflammatory bowel lesions. The pathogenicity of H pylori is dependent on its urease production. Immunization to urease can render H pylori non pathogenic. Cirrhotics develop encephalopathy and hyperammonemia because their livers fail to convert all the ammonia in portal venous blood to urea and collaterals develop by passing the liver. Colonic ammonia increases the turnover rate of colonic mucosa. Ammonia absorbed into the portal venous system is transported to the liver where it is reconverted to urea. Absorbed ammonia adversely influences liver function. Infections with urease producing organisms destroy the renal parenchyma and produce struvite stones. Urease immunization aids colonic healing and prevents uremic colitis. Absorbed ammonia is a noxious influence on the liver. Animals immunized to urease regenerate the liver faster and are less susceptible to hepatotoxins. Immunization to urease ameliorates cirrhosis. Proteus and other urease producers become non toxic and do not damage the renal parenchyma. Urease is responsible for the pathogenicity of infections with urease producing organisms. Immunization to urease renders urease producing organisms non pathogenic.
LeVeen
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HH
Department of Surgery, Medical University of South Carolina, Charleston.
LeVeen
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LeVeen
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D000641:Ammonia / Q000633:toxicity; D000818:Animals; D004285:Dogs; D016481:Helicobacter Infections / Q000201:enzymology; D016480:Helicobacter pylori; D006501:Hepatic Encephalopathy / Q000139:chemically induced / Q000201:enzymology; D006801:Humans; D010437:Peptic Ulcer / Q000201:enzymology; D051381:Rats; D014510:Urease / Q000378:metabolism*
D000641:Ammonia; D014510:Urease