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Primary CTC and OC screening strategies resulted in similar detection rates for advanced neoplasia, although the numbers of polypectomies and complications were considerably smaller in the CTC group. These findings support the use of CTC as a primary screening test before therapeutic OC.

Many bacteria produce extracellular molecules which function in cell-to-cell communication. One of these molecules, autoinducer 2 (AI-2), was first described as an extracellular signal produced by Vibrio harveyi to control luciferase expression. Subsequently, a number of bacteria have been shown to possess AI-2 activity in their culture supernatants, and bear the luxS gene product, which is required for AI-2 synthesis. In Porphyromonas gingivalis, luxS and pfs, encoding a 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTA/SAH'ase), form an operon, suggesting that Sadenosylhomocysteine (SAH) or 5'-methylthioadenosine (MTA) serves as a substrate for AI-2 production. Cell-free extracts of Escherichia coli MG1655, but not DH5α (which carries a luxS frame-shift mutation) were capable of generating AI-2 activity upon addition of SAH, but not MTA. S-Ribosylhomocysteine (RH) derived from SAH also served as a substrate in E. coli MG1655 extracts. RH-supplemented cell-free extracts of Pseudomonas aeruginosa, a bacterium that lacks luxS, only generated AI-2 activity following the introduction of a plasmid containing the Por. gingivalis pfs-luxS operon. In addition, defined in vitro systems consisting of the purified LuxS proteins from Por. gingivalis, E. coli, Neisseria meningitidis or Staphylococcus aureus converted RH to homocysteine and a compound that exhibits AI-2 activity. 4-Hydroxy-5-methyl-3(2H)-furanone was identified by mass spectrometry analysis as a major product formed in this in vitro reaction. In E. coli MG1655, expression of T3SH [the bacteriophage T3 S-adenosylmethionine (SAM) hydrolase] significantly reduced AI-2 activity in culture supernatants, suggesting that AI-2 production is limited by the amount of SAH produced in SAM-dependent transmethylase reactions. The authors suggest that the LuxS protein has an important metabolic function in the recycling of SAH. They also show that Ps. aeruginosa is capable of removing AI-2 activity, implying that this molecule may act as a nutrient. In many bacteria AI-2 may in fact represent not a signal molecule but a metabolite which is released early and metabolized in the later stages of growth.

BackgroundScrub typhus, a bacterial infection caused by Orientia tsutsugamushi, is increasingly recognized as an important cause of fever in Asia, with an estimated one million infections occurring each year. Limited access to health care and the disease’s non-specific symptoms mean that many patients are undiagnosed and untreated, but the mortality from untreated scrub typhus is unknown. This review systematically summarizes the literature on the untreated mortality from scrub typhus and disease outcomes.Methodology/Principal FindingsA literature search was performed to identify patient series containing untreated patients. Patients were included if they were symptomatic and had a clinical or laboratory diagnosis of scrub typhus and excluded if they were treated with antibiotics. The primary outcome was mortality from untreated scrub typhus and secondary outcomes were total days of fever, clinical symptoms, and laboratory results. A total of 76 studies containing 89 patient series and 19,644 patients were included in the final analysis. The median mortality of all patient series was 6.0% with a wide range (min-max) of 0–70%. Many studies used clinical diagnosis alone and had incomplete data on secondary outcomes. Mortality varied by location and increased with age and in patients with myocarditis, delirium, pneumonitis, or signs of hemorrhage, but not according to sex or the presence of an eschar or meningitis. Duration of fever was shown to be long (median 14.4 days Range (9–19)).ConclusionsResults show that the untreated mortality from scrub typhus appears lower than previously reported estimates. More data are required to clarify mortality according to location and host factors, clinical syndromes including myocarditis and central nervous system disease, and in vulnerable mother-child populations. Increased surveillance and improved access to diagnostic tests are required to accurately estimate the untreated mortality of scrub typhus. This information would facilitate reliable quantification of DALYs and guide empirical treatment strategies.

Earlier studies have shown that the cross-sectional area of the deglutitive upper esophageal sphincter (UES) opening in healthy asymptomatic elderly individuals is reduced compared with healthy young volunteers. The aim of this study was to determine the effect of a head-raising exercise on swallow-induced UES opening and hypopharyngeal intrabolus pressure in the elderly. We studied a total of 31 asymptomatic healthy elderly subjects by videofluoroscopy and manometry before and after real (19 subjects) and sham (12 subjects) exercises. A significant increase was found in the magnitude of the anterior excursion of the larynx, the maximum anteroposterior diameter, and the cross-sectional area of the UES opening after the real exercise (P < 0.05). These changes were associated with a significant decrease in the hypopharyngeal intrabolus pressure studied in 12 (real-exercise) and 6 (sham-exercise) subjects (P < 0.05). A similar effect was not found in the sham-exercise group. In normal elderly subjects, deglutitive UES opening is amenable to augmentation by exercise aimed at strengthening the UES opening muscles. This augmentation is accompanied by a significant decrease in hypopharyngeal intrabolus pressure, indicating a decrease in pharyngeal outflow resistance. This approach may be helpful in some patients with dysphagia due to disorders of deglutitive UES opening.

A wide spectrum of anomalies of the pancreas, the pancreatic ductal system, and the biliary tree are commonly encountered at radiologic evaluation. These anomalies may simulate various neoplastic, inflammatory, and posttraumatic conditions and should be part of the differential diagnosis for a variety of abnormalities found at diagnostic imaging. Anatomic variants, developmental anomalies (eg, pancreas divisum, annular pancreas, ectopic pancreas, pancreatic agenesis and hypoplasia), and congenital diseases (congenital pancreatic cysts, von Hippel-Lindau disease, choledochal cysts), in addition to potential imaging pitfalls (uneven distribution of fat, "pseudomasses"), can all pose a diagnostic challenge for the radiologist. Familiarity with these anomalies, the imaging techniques available for their study, and their variable imaging manifestations is necessary for differentiating them from other biliary and pancreatic conditions. A basic understanding of the embryologic development and normal anatomy of the pancreas and biliary tree is also essential for identifying these anomalies.

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