The endocoil stent for malignant biliary obstruction.

The Endocoil (Instent, Inc., Eden Prairie, MN), first introduced in 1993, is a self-expandable nitinol stent made of a coil spring of nickel-titanium alloy. Advantages of the Endocoil in patients with malignant biliary obstruction were thought to include increased radial force with more rapid stricture dilation, inhibition of tumor ingrowth caused by the stent's coil framework with closed approximation of loops, and the possibility for endoscopic removal. Unfortunately, in subsequent reports of patients undergoing Endocoil placement, there have been significant problems with incomplete expansion or twisting during deployment, stent migration, and tumor ingrowth. This article reviews the available literature regarding Endocoil placement for malignant biliary obstruction and addresses the authors' experience at a tertiary referral center.

Calcium carbonate in cholesterol gallstones: polymorphism, distribution, and hypotheses about pathogenesis.

This study of sets of cholesterol gallstones collected consecutively from 222 patients in La Paz, Bolivia, and Mexico City, Mexico, has developed a reliable infrared (IR) spectroscopic method for the detection of calcium carbonate in cholesterol gallstones and provided the basis for simultaneous identification of each of its three polymorphs: calcite, vaterite, and aragonite. The peaks in the 854 to 876 cm-1 region demonstrated 98% sensitivity and specificity for carbonate detection. As little as 3% carbonate by weight could be detected using these peaks. The overall incidence of carbonate was 19% in these populations containing a high proportion of Amerinds. Infrared microspectroscopy of 10 to 50 microns particles, dissected from stones, allowed a ring-by-ring examination of 11 carbonate-containing stones. It was determined that different carbonate polymorphs, when present in the same gallstone, almost always occurred in separate rings. In approximately half of the gallstones, different polymorphs were present in successive layers in the same stone, indicating that conditions governing stone growth changed cyclically. Carbonates were usually precipitated in peripheral layers rather than in the center, supporting the theory that formation of calcium carbonates may be related to episodes of intermittent obstruction of the cystic duct, as opposed to being a major factor in stone nidation.

Clostridium difficile diarrhea in patients with AIDS versus non-AIDS controls. Methods of treatment and clinical response to treatment.

We reviewed the hospital charts of 17 patients with AIDS and Clostridium difficile diarrhea to determine antibiotic use before C. difficile infection, methods of treatment for C. difficile diarrhea, and response of diarrhea to treatment. Left shift and total white blood cell count before and after treatment for C. difficile were also determined. Non-HIV-infected patients with C. difficile diarrhea served as controls. In the patients with AIDS, resolution of diarrhea was noted in 15 (88%) patients. In 25 (76%) control patients, diarrhea resolved with treatment. The patients with AIDS also had a significant decrease (p < 0.05) in left shift in white blood cell count with treatment; the controls did not. Our study therefore suggests that C. difficile diarrhea is at least as likely to resolve with antibiotic therapy in patients with AIDS as it is in those with the non-AIDS-related disorder. We also found that patients with AIDS and C. difficile diarrhea are more likely than patients without AIDS to have a decreased left shift in white blood cell count after antibiotic therapy.