Prevalence of buried Barrett's metaplasia in patients before and after radiofrequency ablation.

BACKGROUND AND STUDY AIM: Radiofrequency ablation (RFA) to treat Barrett's esophagus is increasingly accepted. Description of the etiology, natural history, and prevalence of buried Barrett's metaplasia (BBM) following RFA is limited, although BBM continues to pose a clinical dilemma. We aimed to assess the prevalence, characteristics, and eradication rate of BBM in patients with both dysplastic and nondysplastic Barrett's esophagus, treated with RFA and followed over time. PATIENTS AND METHODS: The presence of Barrett's esophagus, dysplasia, and BBM, before and after RFA, was assessed by two gastrointestinal pathologists in a retrospective chart review of patients who had undergone RFA at our center and had completed appropriate follow-up. RESULTS: We identified 112 patients with completed treatment and no further planned RFA. In 108, no residual Barrett's esophagus was seen after RFA; 4 patients with persistent Barrett's tissue underwent surgery. Regarding BBM, 17/112 patients (15.2%) had evidence of BBM during evaluation. In 12/17 (70.5%) BBM was found during the RFA treatment, with 8 having previously undergone non-RFA therapy and RFA for Barrett's esophagus and 4 having no previous intervention. In 5/17 (29.4%), BBM was seen only after RFA monotherapy. All 17 showed no evidence of BBM at final evaluation and were classified in the complete remission group (108/112). CONCLUSION: Both Barrett's esophagus and BBM were completely eradicated in all patients with long-term follow-up after RFA. Almost half of the patients with BBM had a prior history of non-RFA therapy for Barrett's esophagus compared with 26% the non-BBM cohort. All patients with previously identified Barrett's esophagus and BBM were completely cleared of disease at final follow-up.

Clinical predictors of small intestinal bacterial overgrowth by duodenal aspirate culture.

BACKGROUND: There has been increasing interest in small intestinal bacterial overgrowth (SIBO) after reports of a link with irritable bowel syndrome (IBS), yet our understanding of this entity is limited. AIM: Our aim was to estimate the yield of patients undergoing duodenal aspirate culture, and to identify symptoms and features that predict SIBO. METHODS: A medical chart review of patients who had undergone duodenal aspirate culture at an academic medical centre in 2003 was performed to record clinical characteristics and culture results. The associations between aspirate results and symptoms, medical diagnoses and medication use were assessed using logistic regression. RESULTS: A total of 675 patients had available aspirate results. Mean age of the sample was 53 (s.d. 17) and 443 (66%) were female patients. Overall, 8% of aspirates were positive for SIBO; 2% of IBS patients had SIBO. Older age, steatorrhoea and narcotic use were associated with SIBO (P < 0.05). PPI use was not associated with SIBO, but was associated with bacterial growth not meeting criteria for SIBO (P < 0.05). Inflammatory bowel disease (IBD), small bowel diverticula and pancreatitis were positively associated with an abnormal duodenal aspirate (P < 0.05), but other conditions including IBS were not associated with SIBO. CONCLUSION: Older age, steatorrhoea, narcotic use, IBD, small bowel diverticula and pancreatitis were associated with small intestinal bacterial overgrowth based on abnormal duodenal aspirate culture results. However, no clear associations of true small intestinal bacterial overgrowth with IBS or PPI use were detected, in contrast to recent speculation.

Rhesus rhadinovirus infection in healthy and SIV-infected macaques at Tulane National Primate Research Center.

Rhesus rhadinovirus (RRV) infection was quantified in peripheral blood mononuclear cells (PBMC) from healthy and simian immunodeficiency virus (SIV)-infected rhesus macaques (Macaca mulatta) at the Tulane National Primate Research Center and in a large collection of simian acquired immunodeficiency syndrome--(SAIDS)-associated lymphomas. Quantification of RRV load was performed by real-time PCR using amplification primers specific for the RRV interleukin-6 homologue (RRV vIL-6). RRV infection was detected infrequently and at low levels in PBMC of randomly selected healthy animals. Examination of longitudinally collected PBMC from 22 SIV-infected animals throughout progression to SAIDS revealed similarly low RRV loads that sometimes increased with advancing disease. RRV infection was detected more frequently in the peripheral blood of SIV-infected animals than in healthy animals. Examination of SAIDS-associated lymphomas showed that RRV is rare within the tumor mass, likely representing infection in an occasional tumor-infiltrating cell or contaminating blood. The results indicate that RRV infection in PBMC is not predictive of, and is apparently not required for, development of lymphoma or hyperplastic lymphadenopathy in SIV-infected animals at TNPRC.

Alkoxypsoralens, novel nonpeptide blockers of Shaker-type K+ channels: synthesis and photoreactivity.

A series of psoralens and structurally related 5,7-disubstituted coumarins was synthesized and investigated for their K+ channel blocking activity as well as for their phototoxicity to Artemia salina and their ability to generate singlet oxygen and to photomodify DNA. After screening the compounds on Ranvier nodes of the toad Xenopus laevis, the affinities of the most promising compounds, which proved to be psoralens bearing alkoxy substituents in the 5-position or alkoxymethyl substituents in the neighboring 4- or 4'-position, to a number of homomeric K+ channels were characterized. All compounds exhibited the highest affinity to Kv1.2. 5,8-Diethoxypsoralen (10d) was found to be an equally potent inhibitor of Kv1.2 and Kv1.3, while lacking the phototoxicity normally inherent in psoralens. The reported compounds represent a novel series of nonpeptide blockers of Shaker-type K+ channels that could be further developed into selective inhibitors of Kv1.2 or Kv1. 3.