Mucosal damage

Dactinomycin, an antineoplastic dmg, was discovered in 1943 and is made in rather pure form by StreptomjcesparvuUus. Dactinomycin has some bacteriostatic antibacterial and antifungal activity, but high toxicity limits its use to antineoplastic therapy. It may be used alone or with other antineoplastics, with or without surgery and synergistic x-ray therapy. Dose limiting bone marrow toxicity may result in low white cell and platelet count. Intestinal mucosal damage also occurs. Reviews of more detailed chemotherapeutic information are available (217—222). 

A number of studies have demonstrated protection against ethanol-induced gastric mucosal damage with several antioxidants, including SOD, catalase, allopurinol, DMSO, thiourea, dimethylthiourea, propylgallate and sulphydryl-containing substances, such as cysteine and... 

Several studies have demonstrated the production of mucosal damage and/or increased mucosal permeability by hydrogen peroxide, the hydroxyl radical, or by installation of xanthine or glucose oxidase (Gregaard et al., 1982 Parks et al., 1984 Joubert-Smith et al., 1991 Kohen etal., 1992). 

Production of Mucosal Damage 2.3.1.2.1 Cell culture Stimulated neutrophils are known to be cytotoxic to cells in vitro (Dull et al., 1987 Dallegri et al., 1990 Grisham et al., 1990b). Several in vitro systems have been used to demonstrate oxidative damage to intestinal cells. Xanthine/XO increased Cr release and decreased [ H]thymidine uptake by IEC-18 small intestinal epithelial cell monolayers in a dose-dependent manner (Ma et al., 1991). Rat enterocytes show decreased trypan blue exclusion and increased protein release when incubated with neutrophils stimulated... 

Humans Hydrogen peroxide has been used as an enema or as a cleaning agent for endoscopes and may cause mucosal damage when applied to the surface of the gut wall. Hydrogen peroxide enteritis can mimic an acute ulcerative, ischaemic or pseudomembranous colitis, and ranges from a reversible, clinically inapparent process to an acute, toxic fulminant colitis associated with perforation and death (Bilotta and Waye, 1989). It is conceivable that anecdotal reports of exacerbation of IBD by iron supplementation (Kawai et al. 1992) are mediated by hydroxyl radical production by the Fenton reaction. 

Loguercio, C., Taranto, D., Beneduce, F., Del Vecchio Blanco, C., De Vincentis, A., Nardi, G. and Romano, M. (1993). Glutathione prevents ethanol induced gastric mucosal damage and depletion of sulphydryl compounds in humans. Gut 34, 161-165. 

Mozsik, G., Siito, G., Garamszegi, M., Javor, T., Nagy, L., Vineze, A. and Zsoldos, T. (1991). Oxygen free radicals and gastric mucosal damage in rats treated with ethanol and HCl Eur. J. Gastroenterol. Hepatol. 3, 757-761. 

Szeleyni, I. and Brune, K. (1988). Possible role of ox) n free radicals in ethanol-induced gastric mucosal damage in rats. Dig. Dis. Sci. 33, 865-871. 

Stress-Related Mucosal Damage Prophylaxis Protocol... 

Convincing evidence on the efficacy of enteral nutrition in the prevention of stress-related mucosal damage not... 

Patients presenting with atypical symptoms may require higher doses and longer treatment courses than patients with typical symptoms. These patients are best diagnosed with ambulatory pH testing or an empiric trial with a PPI.23 These tests can confirm reflux in patients who have persistent symptoms without evidence of mucosal damage by endoscopy.1 In patients presenting with non-cardiac chest pain, a short course (1 to 8 weeks) of omeprazole 20 mg twice daily has been advocated.23... 

Dependence on acid for mucosal damage Greater Lesser Lesser... 

Gl, gastrointestinal H. pylori, Helicobacter pylori NSAID, non-steroidal anti-inflammatory drug SRMD, stress-related mucosal damage. 

Stress-related mucosal damage occurs most frequently in critically ill patients and is thought to be caused by factors such as compromised mesenteric perfusion rather than HP or NSAIDs. Its onset is usually acute, and in a small proportion of patients may progress to deep ulceration and hemorrhage. 

Hydrochloric acid and pepsin are the primary substances that cause gastric mucosal damage in PUD. Three different stimuli... 

Non-selective NSAIDs [those that inhibit both cyclooxygenase-1 and -2 (COX-1 and COX-2)] cause gastric mucosal damage by two primary mechanisms (1) a direct toxic interaction and (2) systemic pharmacologic actions. 

Intravenous histamine-2-receptor antagonists such as ranitidine, famotidine, and cimetidine are compatible with PN and can be added to the daily PN for prevention of stress-related mucosal damage and peptic ulcer disease. This provides a continuous acid suppression and reduces nursing time by avoiding intermittent scheduled infusions. 

Gastroesophageal reflux disease Symptoms or mucosal damage that result from abnormal reflux of gastric contents into the esophagus. 

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