Antiinflammatory effects of various drugs on acetic acid induced colitis in the rat

The efficacy of various drugs used to treat ulcerative colitis, (sulfasalazine, 5-aminosalicylate, hydrocortisone) was investigated in a model of acetic acid-induced colitis in the rat. Subsequently, we tested the ability of antioxidant/5-lipoxygenase inhibitors (gossypol and nordihydroguiaretic acid [NDGA]) and a cyclooxygenase inhibitor (indomethacin) to attenuate the macroscopic colonic damage and/or neutrophil influx (myeloperoxidase activity [MPO]) associated with this model of colitis. Oral pretreatment with either sulfasalazine, gossypol, or NDGA significantly decreased colonic MPO activity induced by acetic acid. Intrarectal administration of such drugs resulted in an even larger reduction of the colonic inflammation, with gossypol being the most potent compound. Oral or intrarectal administration of corticosteroids (dexamethasone, hydrocortisone) also attenuated the parameters of acetic acid induced colitis. In contrast, pretreatment with indomethacin was ineffective, or when administered daily after colitis induction, indomethacin actually increased colonic neutrophil influx significantly. Our data suggest that both the route of drug administration and dosing regimen employed affect the antiinflammatory potency and/or efficacy of compounds on colitis induced by acetic acid in the rat. Drugs which were effective against this colitis may act by scavenging of oxygen derived free radicals.     

Coombs-positive hemolytic anemia preceding ulcerative proctitis

A 12-year-old girl is described who developed rectal bleeding 5 months after being diagnosed as having a Coombs-positive hemolytic anemia. Colonoscopy showed that the rectal bleeding was due to ulcerative proctitis. This is the first case report of Coombs-positive hemolytic anemia preceding the onset of ulcerative proctitis in a child.     

Expression of opioid peptides in tumors

We looked for opioid peptides and their precursors in 108 tumors of both neuroendocrine and nonneuroendocrine origin, using a monoclonal "pan-opioid" antibody, 3-E7, which recognizes the tetrapeptide Tyr-Gly-Gly-Phe (the sequence responsible for pharmacologic activity in all known opioid peptides), in conjunction with polyclonal antibodies directed against representative peptides of each of the three precursors (alpha-endorphin, [met]enkephalin-Arg-Gly-Leu, and dynorphin B). Using the avidin-biotin immunoperoxidase technique, we observed consistent cytoplasmic immunoreactivity (at least focally) in all of 15 adrenal pheochromocytomas, all of 6 thyroid medullary carcinomas, and all of 5 pituitary adenomas. Opioid staining was also observed in parathyroid adenomas (8 of 9), pancreatic islet-cell tumors (7 of 10), carcinoid tumors from various sites (18 of 26), and paragangliomas (1 of 2). There was no immunoreactivity in pulmonary small-cell carcinomas, Merkel-cell tumors of skin, neuroblastomas, or any of the non-neuroendocrine tumors examined. The expression of alpha-endorphin, [met]enkephalin-Arg-Gly-Leu, and dynorphin B varied from tumor to tumor; however, positive staining with the "pan-opioid" antibody was found in each tumor containing at least one of the three precursors. Opioid peptide immunoreactivity was also detected in non-neoplastic cells of the adrenal medulla, pancreatic islets, pituitary, intestinal and bronchial mucosa, and intestinal myenteric plexuses. We conclude that opioid expression within tumors is most likely due to enhanced expression of a normal cell product and that opioid peptides are useful markers of neuroendocrine differentiation in many tumors.     

Osteopetrosis: MR characteristics at 1.5 T

Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements.