No abstract

SUMMARYAim: To conduct a placebo-controlled functional brain imaging study to assess the effect of the 5-hydroxytryptamine-3 receptor antagonist, alosetron, on irritable bowel syndrome symptoms, regional brain activation by rectosigmoid distension and associated perceptual and emotional responses. Methods: Fifty-two non-constipated irritable bowel syndrome patients (28 female) were enrolled in a randomized, placebo-controlled trial with alosetron (1-4 mg b.d.). Thirty-seven patients completed both brain scans following randomization. Rectosigmoid stimulation was performed with a computer-controlled barostat. Changes in regional cerebral blood flow were assessed using H 15 2 O positron emission tomography. Stimulus ratings and changes in gastrointestinal symptoms were assessed using verbal descriptor scales.Results: Alosetron, but not placebo, treatment was associated with a decrease in symptom ratings, and reductions in emotional stimulus ratings. Compared to baseline, alosetron treatment was associated with reduced regional cerebral blood flow in bilateral frontotemporal and various limbic structures, including the amygdala. Compared to placebo, decreases in activity of the amygdala, ventral striatum, hypothalamus and infragenual cingulate gyrus were significantly greater after alosetron. Conclusions: In non-constipated irritable bowel syndrome patients, 3 weeks of treatment with a 5-hydroxytryptamine-3 receptor antagonist decreases brain activity in response to unanticipated, anticipated and delivered aversive rectal stimuli in structures of the emotional motor system, and this is associated with a decrease in gastrointestinal symptoms.

CT and MRI provide complementary findings suggesting advanced pulmonary artery sarcoma instead of chronic thromboembolism.

We report on a patient who developed Legionella pneumonia after bone marrow transplantation. Despite appropriate antibiotic treatment, disease progressed. The patient developed a lung abscess from which Legionella and Prevotella were isolated. Cure was achieved by surgical resection. The resected material was sterile, but 16S ribosomal DNA analysis revealed Legionella DNA.

Psychological stress and colitisQiu BS, Vallance BA, Blennerhassett PA, Collins SM. The role of CD4+ lymphocytes in the susceptibility of mice to stress-induced reactivation of experimental colitis. Nat Med 1999;5:1178-82. AbstractIdiopathic inflammatory bowel disease is a chronic relapsing condition. The role of stress in causing relapses of inflammatory bowel disease remains controversial. We now show that colitis induced in mice by dinitrobenzenesulfonic acid (DNBS) resolves by 6 weeks, but can subsequently be reactivated by stress plus a sub-threshold dose of DNBS, but not by DNBS alone. Stress reduced colonic mucin and increased colon permeability. Susceptibility to reactivation by stress required CD4+ lymphocytes and could be adoptively transferred. We conclude that stress reactivates experimental colitis by facilitating entry of luminal contents that activate previously sensitized CD4 cells in the colon. CommentIn cardiovascular disease, the role of stressful life events, personality profiles, and aVective disorders as risk factors for the development of morbidity and mortality from established coronary artery disease is well established.

Placebos were historically defined as inert substances (e.g., sugar or bread pills) that cause symptom improvement but are now characterized more broadly to include contextual aspects of both active and inactive treatments that contribute to symptom improvement in therapeutic settings. These contexts may be associated with the environment, including the size and color of a pill, a doctor's demeanor, or the invasiveness and cost of a treatment. The context may also be generated by the patient's prior experience or expectations about the efficacy of a treatment. Placebo effects are cognitive, behavioral, or biological responses to these contextual aspects of treatment.Although placebo effects may be a nuisance for clinical trials, they remain an important tool for clinicians and often prove beneficial for patients. Despite their efficacy, the scientific community has tended to regard placebo effects as noise rather than a potential topic of research. However, a major paradigm shift has generated renewed interest in investigating neurocognitive and neurochemical mechanisms that drive placebo effects. The timing of this renewed interest overlaps with increasing access to neuroimaging tools, allowing for investigation of these underlying mechanisms that cannot be readily assessed via self-report or observation alone. Neuroimaging as a tool to identify mechanisms driving placebo effectsLike all mammals, humans are well equipped with endogenous mechanisms designed to maintain homeostasis in the face of a perturbation. When these systems are engaged, the body uses its own resources to promote healing and relief from distress. Placebos have the capacity to activate these endogenous mechanisms, but how do they do so?Most studies investigating placebo effects have focused on measuring extent of symptom improvement following administration of an inert placebo. Although these studies inform our understanding of the magnitude, frequency, and pervasiveness of placebo effects, they have done relatively little to clarify the underlying mechanisms of these effects. Using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), investigators can gain insight into the neurobiological mechanisms driving placebo effects by relating this neurobiological activity to symptom improvement. By applying knowledge

Visceral pain is characterized by a subjectively painful perception located in the abdominal area. Distinct structural lesions or biochemical abnormalities which could serve as explanation for these painful sensations can be only detected in a proportion of patients. In the absence of precise causes for visceral pain, the symptoms are attributed to functional disorders. The two major single entities among functional disorders of the gut are functional dyspepsia and irritable bowel syndrome. Patients with functional dyspepsia characteristically localize the symptoms in the upper abdomen. Functional gastrointestinal disturbances which are localized in the lower abdomen are summarized as irritable bowel syndrome. Interestingly,both functional dyspepsia and irritable bowel syndrome may overlap.

No abstract