One hundred and seventeen coded intestinal biopsies were examined by electron microscopy and evaluated for morphological evidence of mast cell and basophil secretion in situ. Sixty percent of the biopsies had evidence of secretion. Mast cell secretion was evident in control biopsies, many of which were obtained from uninvolved tissues of patients with inflammatory bowel disease. Biopsies of inflamed continent pouches from ulcerative colitis (UC) patients showed more mast cell secretion than noninflamed UC pouch biopsies. This evidence of mast cell secretion supports recent work that documents high constitutive levels of histamine in jejunal fluids of Crohn’s disease patients and suggests a proinflammatory role for mast cells in inflammation associated with pouchitis.

We used light and electron microscopy to analyze the eyelid inflammation that develops in transgenic mice that overexpress interleukin-4 (IL-4; Tepper et al, Cell 62:457, 1990). Analysis of alkaline Giemsa-stained plastic sections examined by light microscopy (Dvorak et al, J Exp Med 132:558, 1970), as well as by routine transmission electron microscopy, indicated that the mast cells in the inflammatory eyelid lesions were undergoing piecemeal degranulation, a form of secretion in which the cells' cytoplasmic granules exhibit characteristic morphologic changes that are thought to be associated with the prolonged, vesicle-mediated release of the granules' constituents. Moreover, by using a newly reported enzyme affinity-gold method, which stains histamine based on binding to diamine oxidase-gold (Dvorak et al, J Histochem Cytochem 41:787, 1993), we show that these activated mast cells had released much of their histamine content. The eyelid lesions also exhibited increased numbers of mast cells; interstitial fibrosis, particularly around cutaneous nerves and blood vessels; activated fibroblasts; focal axonal damage; venules with endothelial cells containing numerous vesiculo-vacuolar organelles; and infiltrates of neutrophils and eosinophils. Our findings illustrate that overexpression of the IL-4 gene in vivo can result in eyelid lesions associated with piecemeal degranulation of mast cells, as well as tissue fibrosis and a variety of other pathologic changes. These results also represent the first direct morphologic evidence for histamine secretion by mast cells in vivo.

Mortality was low in children with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome, being central nervous system involvement the main cause of death. The best mortality predictors found were central nervous system involvement, hemoglobin, and sodium concentration. Hyponatremia may be a new Shiga toxin-producing Escherichia coli hemolytic uremic syndrome mortality predictor.

The ultrastructural finding of axonal necrosis in Crohn's disease confirms previous studies. The presence of damaged enteric nerves in patients with pouchitis provides ultrastructural support to the clinical impression of similarities between pouchitis and Crohn's disease. The association of damaged nerves and invasive bacteria in pouchitis suggests mechanistic similarities for the pathogenesis of Crohn's disease that requires further investigation.

This study examined the interactive effects of imagined rejection and narcissism on cardiovascular reactivity (CVR). Participants completed measures of overt narcissism (Narcissistic Personality Inventory, NPI; Raskin & Hall, 1979), overt–covert narcissism (Margolis & Thomas, 1980), and trait self‐esteem. They then imagined 2 scenarios culminating in either interpersonal acceptance or rejection. Systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were assessed before, during, and after the imagery. Overt–covert narcissism was positively associated with task increases in SBP and DBP and recovery elevation of HR following rejection, but not acceptance. Similar effects on SBP were found for the Entitlement/Exploitativeness dimension of the NPI. Lower self‐esteem predicted greater task increases in SBP, DBP, and HR across conditions. Implications for health are discussed.