Donald R. Taylor

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.

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 μm 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. (Hepatology 1995;22:488–496.)

Activation of human neutrophils by calcium carbonate polymorphs.

Gallstone formation is frequently accompanied byinflammation of the gallbladder mucosa. Some gallstonecomponents such as cholesterol, calcium bilirubinate,and calcium hydroxyapatite have been previously shown to activate neutrophils. We investigatedthe effect on neutrophils of the calcium carbonatepolymorphs aragonite, calcite, and vaterite (all foundin gallstones). By chemiluminescence, superoxide, and degranulation assay, all three crystalswere shown to cause rapid activation of neutrophils. Thepotency of the crystals was aragonite > vaterite >calcite. In vivo, crystals may be plasma-protein-coated before they encounter neutrophils; thereforesome experiments were repeated using crystals that hadbeen preincubated with plasma. For aragonite andvaterite, protein adsorption decreased thechemiluminescence response by approximately 50%. In contrast,protein-coated calcite crystals elicited a greaterchemiluminescence response than did uncoated crystals.In summary, the calcium carbonate polymorphs are potent activators of neutrophils and thus have thepotential to contribute to gallstone-associatedcholecystitis.

Other clinical studyCalcium 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 μm 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. (Hepatology 1995;22:488–496.)