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Vitamin E has previously been shown to provide radioprotection in animal models: increased survival after whole-body irradiation, diminished absorptive malfunction, and modest diminution in postirradiation hemolysis. The lumenal route for intestinal radioprotection has not been tested. MethodsRat mid-small bowel was surgically exteriorized and segmented by ties into compartments, each of which was filled with a test solution 30 minutes before 1 100 cGy of x-irradiation was administered. After the rats were killed 5 days later, the various segments were evaluated for surviving crypts, mucosal height, and goblet cell preservation. Lumenal agents included alphatocopherol phosphate and alpha-tocopherol acetate. In a separate study, dietary supplements of alpha-tocopherol were given for 10 days before irradiation, and the same irradiation sequence was carried out. ResultsSmall bowel crypt cell numbers, mucosal height, and goblet cell numbers were significantly protected from radiation effects by dietary alpha tocopherol pretreatment and by lumenal application of the vitamin. ConclusionsThese studies indicate that vitamin E can serve as a partial protectant against acute irradiation enteritis, whether given as chronic oral systemic pretreatment or as a brief topical application. 504Therapeutic irradiation regimens are designed to maximize tumoricidal effects while causing minimal damage to normal organs. Radiation to abdominal or pelvic malignancies unavoidably injures the intestine. Largely because of rapid cell turnover, the intestine is highly sensitive to radiation injury and is therefore the limiting factor in the permissible dosage for abdominal and pelvic irradiation. An early clinical consequence of intestinal

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Background. The classic radioprotectant WR‐2721 has been shown to reduce the severity of small bowel injury when administered systemically shortly before irradiation is delivered. This study tested the possibility that WR‐2721 could provide protection when applied topically to intestinal mucosa. The second question addressed was the influence of pH on the effectiveness of this agent. Methods. The model used involved irradiation of exteriorized rat small bowel. A length of intestine was compartmentalized. The various individual segments were filled with a lumenal Tris buffer (pH 9), WR‐2721, or a combination of these two, then irradiated with 1100 cGy. The animals were sacrificed 5 days later. Surviving crypt cells and mucosal height were the criteria used to quantitate mucosal injury. Results. The pH 9 buffer alone provided a small (16%) but significant preservation of crypt cell numbers. WR‐2721 improved crypt survival by 54% at neutral pH, 83% at pH 9. Conclusions. These data indicate that WR‐2721, when applied topically to the small bowel mucosa of the rat before irradiation, provides substantial protection against radiation damage. The degree of benefit is amplified greatly when the drug is in an alkaline medium.

Probucol is a lipid-regulating drug that also has antioxidant properties. This study was designed to test the possibility that probucol could provide radioprotection of the intestine when administered either intralumenally or systemically. Tissue damage was evaluated histologically by quantifying the number of crypts per circumference and the mucosal height. Animals were sacrificed 5 days after 11 Gy of X irradiation. In one series of experiments, a loop of mid small bowel was exteriorized operatively and compartmentalized into segments, each filled with probucol or saline. Intralumenal administration of probucol prior to irradiation led to a significantly greater number of crypts per circumference and mucosal height compared to saline-filled irradiated controls. In another series of experiments, five groups of rats were irradiated: (1) probucol in the small bowel lumen, (2) intravenous probucol, (3) probucol by gavage, (4) probucol added to standard rat chow and (5) saline control. In the rats given probucol intravenously prior to X irradiation, crypt numbers and mucosal height were significantly enhanced. Probucol given by gavage also resulted in protection. Rats fed a diet containing probucol showed no significant protection. Topical administration was more effective than systemic. Probucol protects the intestinal mucosa from acute radiation damage when given topically, intravenously or by gavage, but does not do so when given as a dietary supplement.

Metastatic neoplasms to the gastrointestinal (GI) tract are an uncommon entity and in extremely rare cases originate from the breast. The clinical manifestations of metastatic breast cancer into the GI tract are frequently non-specific, and the interval between the diagnosis of lobular carcinoma and GI metastasis can often delay up to 30 years. Here, we present a 73-year-old female with an unusual colonoscopy that revealed a submucosa nodular infiltrate throughout all the colon with a cobblestone-like appearance, which was later confirmed to be metastatic lobular carcinoma of the breast that was surgically removed 15 years early. A couple of months later, she developed malignant small bowel obstruction and laparotomy revealed extended small bowel and colonic metastatic involvement.