Initial experience with the Pentax VSB-P2900 enteroscope.

Pentax has introduced the VSB-P2900 for endoscopic evaluation of the small bowel. This is a standard video upper endoscope lengthened to 250 cm. We report a case utilizing this instrument. A 65-yr-old white male was admitted with respiratory failure. Gastrointestinal bleeding developed. Upper endoscopy, colonoscopy, push enteroscopy, and mesenteric angiography were nondiagnostic. Enteroscopy to the proximal to mid ileum was performed. Approximately 90% of the intubated small bowel mucosa was visualized. An arteriovenous malformation and an ulcer were identified and cauterized. Time elapsed from intubation to extubation was 90 min, including two KUBs. No further bleeding was observed. The VSB-P2900 is likely to simplify examination of the small intestine. Tip control allows a large percentage of the intubated small bowel to be visualized. A working channel allows therapeutics. The technique is simple, fast, and within the skills of most endoscopists. A safety and efficacy profile need to be determined.

Loss and restoration of glucagon receptors and responsiveness in a transformed kidney cell line.

A kidney cell line (MDCK) retains an adenylate cyclase system sensitive to glucagon, vasopressin, isoproterenol and prostaglandin E1. The stimulatory effect of glucagon on cAMP production was selectively lost in a cloned line derived from MDCK cells transformed by Harvey murine sarcoma virus. Sensitivity to glucagon was largely restored by treatment of the transformed cells with prostaglandin E1 or butyrate. Loss and reappearance of glucagon receptors seemed to be responsible for the observation. The parental MDCK line produced prostaglandins and in the transformed line, this function was abolished. These observations suggest that synthesis of glucagon receptors is controlled by endogenously produced prostaglandin in MDCK cells and that loss of glucagon receptors and their responsiveness in the transformed cells occurs as a consequence of the inability of these cells to synthesize this prostaglandin.