Mucosa common mucosal

Mucositis and stomatitis are potentially severe and dose-hmiting adverse effects of the anthracyclines. Both the frequency and the severity are dose-dependent (56,69). Their onset and recovery generaUy parallel the hematological toxicity, but they can occur earlier (5-10 days after treatment starts). Areas of painful erosions, mainly along the side of the tongue and on the subhngual mucosa, are common. Mucositis occurs in about 9% of patients who receive oral idambicin in standard doses (27). 

Leiomyoma of the muscularis mucosae is the most common mucosal-based mesenchymal lesion of the GI tract that may present as a polypoid mass." ° " ° These tumors often arise in the colon leiomyomas are also likely to occur within the wall of the esophagus.Unlike many of the previously mentioned lesions, this tumor displaces the colonic crypts and does not grow between crypts. As with leiomyomas elsewhere, these lesions stain strongly with smooth muscle actin and desmin and are negative for c-kit. 

Lazarus NH, Kunkel EJ, Johnston B et al. A common mucosal chemokine (mucosae-associated epithelial chemokine/CCL28) selectively attracts IgA plasmablasts. J Immunol 2003 170(7) 3799-3805. 

The rapidly proliferating cells of the GI tract make them susceptible to the effects of chemotherapy. Mucositis is the inflamed, ulcerated mucosa of the mouth, esophagus, and lower GI tract that may result in infection and pain with subsequent decreased fluid and nutritional intake. Methotrexate, 5-FU, etoposide, and doxorubicin are the chemotherapy agents most commonly associated with mucositis. Patients should be instructed on good oral mouth care and use saline rinses several... 

There are two forms of idiopathic inflammatory bowel disease (IBD) ulcerative colitis, a mucosal inflammatory condition confined to the rectum and colon, and Crohn s disease, a transmural inflammation of GI mucosa that may occur in any part of the GI tract. The etiologies of both conditions are unknown, but they may have a common pathogenetic mechanism. 

Peptic ulcer disease (PUD) refers to a group of ulcerative disorders of the upper GI tract that require acid and pepsin for their formation. Ulcers differ from gastritis and erosions in that they extend deeper into the muscularis mucosa. The three common forms of peptic ulcers include Helicobacter pylori (HP)-associated ulcers, nonsteroidal antiinflammatory drug (NSAID)-induced ulcers, and stress-related mucosal damage (also called stress ulcers). 

Nicolazzo et al. [52] considered the use of the lipophilic skin penetration enhancers, octisalate and padimate (both used in sunscreens), in comparison to Azone on the buccal absorption of various drugs in vitro. They were found to have limited effect in enhancing the permeation of triamcinolone acetonide (although some increase in tissue uptake was proposed in some cases) relative to Azone, while reducing the penetration of estradiol and caffeine. One interesting report is that of the effect of capsaicin from capsicum, a commonly used food ingredient, which has been reported to enhance the permeability of sulfathiazole in human volunteers [53] presumably by a direct irritation effect on the mucosa. This raised an interesting issue of the effect of diet on oral mucosal permeability. 

Recently, several in vitro experiments substantiated the potential of the human vaginal mucosa as a good administration route relating to the degree of permeation when compared with other mucosal surfaces. In fact, the vagina can be more permeable to some commonly used model substances, such as water, 17[3-cstradiol (Figure 3), arecoline, arecaidine, and vasopressin, than colonic or small intestinal mucosa, or at least as permeable as when compared to human buccal mucosa [46,47],... 

IBD is divided into two major subtypes ulcerative colitis and Crohn s disease. Ulcerative colitis is characterized by confluent mucosal inflammation of the colon starting at the anal verge and extending proximally for a variable extent (e.g., proctitis, left-sided cohtis, or pancolitis). Crohn s disease, by contrast, is characterized by transmnral inflammation of any part of the GI tract bnt most commonly the area adjacent to the ileocecal valve. The inflammation in Crohn s disease is not necessarily confluent, frequently leaving skip areas of relatively normal mucosa. The transmural nature of the inflammation may lead to fibrosis and strictures or, alternatively, fistula formation. 

ABSORPTION, DISTRIBUTION, AND ELIMINATION As with vitamin Bj, the diagnosis and management of folic acid deficiency depend on an understanding of the transport pathways and intracellular metabolism of the vitamin (Figure 53-10). Folates present in food are largely in the form of reduced polyglutamates, and absorption requires transport and the action of a pteroyl-glutamyl carboxypeptidase associated with mucosal cell membranes. The mucosae of the duodenum and upper part of the jejunum are rich in dihydrofolate reductase and can methylate most or aU of the reduced folate that is absorbed. Since most absorption occurs in the proximal small intestine, it is not unusual for folate deficiency to occur with jejunal disease. Both nontropical and tropical sprues are common causes of folate deficiency. 

Toxicity Common adverse effects include bone marrow suppression and toxie effects on the skin and gastrointestinal mucosa (mucositis). The toxic effects of methotrexate on normal cells may be reduced by administration of fohnie aeid (leucovorin) this strategy is called leucovorin rescue. Long-term use of methotrexate has led to hepatotoxieity and to pulmonary infiltrates and fibrosis. Salicylates, NSAlDs, sulfonamides, and sulfonylureas enhance the toxicity of methotrexate. 

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