Ischemic Colitis Secondary to Olanzapine and Clonidine Use in a Patient With a History of Laxative Abuse.

Ischemic colitis is the most common type of intestinal ischemia and is caused by an acute arterial occlusion, thrombosis, or hypoperfusion of the mesenteric vasculature. This case centers around a 39-year-old female with a past medical history significant for a 20-year history of stimulant laxative abuse, chronic constipation, bipolar disorder, and anxiety that presented with ischemic colitis following 21 days of obstipation. At the time of presentation, the patient was taking olanzapine 15 mg daily for the treatment of bipolar disorder and clonidine 0.2 mg three times daily for anxiety. Over the course of her hospitalization, the patient was found to have a high stool burden, including calcified stool, contributing to ischemic colitis. She was successfully treated with a clonidine taper, multiple enemas, and laxatives. Pharmacological agents that induce constipation have been shown to increase the risk of colonic ischemia by increasing intraluminal pressure in the colon. Atypical antipsychotics block peripheral anticholinergic and anti-serotonergic receptors, limit gastrointestinal muscle contractions, and delay intestinal transit.

Expression of TCR genes in adult and larval Xenopus laevis.

In order to better understand the development and function of γδ T cells in Xenopus frogs, it is necessary to determine where and when γδ T cells are found in Xenopus tissues. This study examined the expression of TCR genes, focused primarily on TCR γ, in tissues of adult and larval Xenopus laevis and provide new data about the expression pattern of these different TCR genes in this anuran amphibian. TCR gene expression was detected by RT-PCR in adult frog tissues including the thymus, spleen, skin, intestine, lung, and liver, but not the testes. TCR γ and ß genes were detected in the larval (tadpole) tail and intestine. The absence of RAG-1 expression in these larval tissues is consistent with differentiation of the T cells in the thymus. Together, these data provide evidence that migration of these cells from the thymus likely occurs relatively early in larval development. These studies provide a necessary foundation for future studies of the functions of γδ T cells in amphibians, which are placed at an intermediate position flanked by fishes on one end and mammals and chickens on the other.