Comorbidity in irritable bowel syndrome

BACKGROUND: Comorbid nongastrointestinal symptoms account for two-thirds of excess health-care costs in irritable bowel syndrome (IBS). OBJECTIVES: To determine whether IBS patients are at greater risk for specific comorbid disorders versus showing a general tendency to overreport symptoms; whether patients with inflammatory bowel disease (IBD) show patterns of comorbidity similar to IBS; whether comorbidity is explained by psychiatric disease; and whether excess comorbidity occurs in all IBS patients. METHODS: All 3,153 patients in a health maintenance organization with a diagnosis of IBS in 1994-1995 were compared to 3,153 age- and gender-matched controls, and to 571 IBD patients. All diagnoses in a 4-yr period beginning 1 yr before their index visit were categorized as gastrointestinal, psychiatric, or nongastrointestinal somatic. Nongastrointestinal somatic diagnoses were further divided into symptom-based versus biological marker-based diagnoses. RESULTS: Forty-eight of 51 symptom-based and 16 of 25 biomarker-based diagnoses were significantly more common in IBS versus controls. However, there were no unique associations. Bacterial, viral, and fungal infections and stroke were among diagnoses made more frequently in IBS. IBD patients were similar to controls. Greater somatic comorbidity was associated with concurrent psychiatric diagnosis. Only 16% of IBS patients had abnormally high numbers of comorbid diagnoses. CONCLUSIONS: Comorbidity in IBS is due to a general amplification of symptom reporting and physician consultation rather than a few unique associations; this suggests biased symptom perception rather than shared pathophysiology. Comorbidity is influenced by, but is not explained by, psychiatric illness. Excess comorbidity is present in only a subset of IBS patients.     

Attentional bias towards health-threat information in chronic fatigue syndrome

OBJECTIVE: To investigate whether individuals with chronic fatigue syndrome (CFS) show an attentional bias towards health-threat information. METHODS: Attentional bias (AB) was assessed in individuals with CFS and healthy controls using a visual probe task which presented health-threat and neutral words and pictures for 500 ms. Self-report questionnaires were used to assess CFS symptoms, depression, anxiety, and social desirability. RESULTS: Compared to a healthy control group, the CFS group showed an enhanced AB towards heath-threat stimuli relative to neutral stimuli. The AB was not influenced by the type of stimulus (pictures vs. words). CONCLUSION: The finding of an AB towards health-threat information in individuals with CFS is supportive of models of CFS which underlie cognitive behavior therapy.     

Inhibition of microRNA-181 reduces forebrain ischemia-induced neuronal loss

MicroRNA (miRNA), miR-181a, is enriched in the brain, and inhibition of miR-181a reduced astrocyte death in vitro and infarct volume after stroke in vivo. This study investigated the role of miR-181a in neuronal injury in vitro and hippocampal neuronal loss in vivo after forebrain ischemia. miR-181a levels were altered by transfection with mimic or antagomir. N2a cells subjected to serum deprivation and oxidative stress showed less cell death when miR-181a was reduced and increased death when miR-181a increased; protection was associated with increased Bcl-2 protein. In contrast, transfected primary neurons did not show altered levels of cell death when miR-181a levels changed. Naive male rats and rats stereotactically infused with miR-181a antagomir or control were subjected to forebrain ischemia and cornus ammonis (CA)1 neuronal survival and protein levels were assessed. Forebrain ischemia increased miR-181a expression and decreased Bcl-2 protein in the hippocampal CA1 region. miR-181a antagomir reduced miR-181a levels, reduced CA1 neuronal loss, increased Bcl-2 protein, and significantly prevented the decrease of glutamate transporter 1. Thus, miR-181a antagomir reduced evidence of astrocyte dysfunction and increased CA1 neuronal survival. miR-181a inhibition is thus a potential target in the setting of forebrain or global cerebral ischemia as well as focal ischemia.     

Microbiological Applications of High-Resolution Melting Analysis

High-resolution melting (HRM) analysis uses real-time PCR instrumentation to interrogate DNA sequence variation and is a low-cost, single-step, closed-tube method. Here we describe HRM technology and provide examples of varied clinical microbiological applications to highlight the strengths and limitations of HRM analysis.