Autofluorescence endoscopy in surveillance of Barrett's esophagus: a multicenter randomized trial on diagnostic efficacy.

BACKGROUND AND STUDY AIMS: The reference surveillance method in patients with Barrett's esophagus is careful endoscopic observation, with targeted as well as random four-quadrant biopsies. Autofluorescence endoscopy (AFE) may make it easier to locate neoplasia. The aim of this study was to elucidate the diagnostic accuracy of surveillance with AFE-guided plus four-quadrant biopsies in comparison with the conventional approach. PATIENTS AND METHODS: A total of 187 of 200 consecutive Barrett's esophagus patients who were initially enrolled (73 % male, mean age 67 years, mean Barrett's segment length 4.6 cm), who underwent endoscopy for Barrett's esophagus in four study centers, were randomly assigned to undergo either AFE-targeted biopsy followed by four-quadrant biopsies or conventional endoscopic surveillance, also including four-quadrant biopsies (study phase 1). After exclusion of patients with early cancer or high-grade dysplasia, who underwent endoscopic or surgical treatment, as well as those who declined to participate in phase 2 of the study, 130 patients remained. These patients were examined again with the alternative method after a mean of 10 weeks, using the same methods described. The main study parameter was the detection of early cancer/adenocarcinoma or high-grade dysplasia (HGD), comparing both approaches in study phase 1; the secondary study aim in phase 2 was to assess the additional value of the AFE-guided approach after conventional surveillance, and vice versa. Test accuracy measures were derived from study phase 1. RESULTS: In study phase 1, the AFE and conventional approaches yielded adenocarcinoma/HGD rates of 12 % and 5.3 %, respectively, on a per-patient basis. With AFE, four previously unrecognized adenocarcinoma/HGD lesions were identified (4.3 % of the patients); with the conventional approach, one new lesion (1.1 %) was identified. Of the 19 adenocarcinoma/HGD lesions detected during AFE endoscopy in study phase 1, eight were visualized, while 11 were only detected using untargeted four-quadrant biopsies (sensitivity 42 %). Of the 766 biopsies classified at histology as being nonneoplastic, 58 appeared suspicious (specificity 92 %, positive predictive value 12 %, negative predictive value 98.5 %). In study phase 2, AFE detected two further lesions in addition to the initial alternative approach in 3.2 % of cases, in comparison with one lesion with conventional endoscopy (1.7 %). CONCLUSIONS: In this referral Barrett's esophagus population with a higher prevalence of neoplastic lesions, the AFE-guided approach improved the diagnostic yield for neoplasia in comparison with the conventional approach using four-quadrant biopsies. However, AFE alone was not suitable for replacing the standard four-quadrant biopsy protocol.

Configurational entropy and collective modes in normal and supercooled liquids.

Soft vibrational modes have been used to explain anomalous thermal properties of glasses above 1 K. The soft-potential model consists of a collection of double-well potentials that are distorted by a linear term representing local stress in the liquid. Double-well modes contribute to the configurational entropy of the system. Based on the Adam-Gibbs theory of entropically driven relaxation in liquids, we show that the presence of stress drives the transition from Arrhenius to Zwanzig-Bässler temperature dependence of relaxation times. At some temperature below the glass transition, the energy scale is dominated by local stress, and soft modes are described by single wells only. It follows that the configurational entropy vanishes, in agreement with the "Kauzmann paradox." We discuss a possible connection between soft vibrational modes and ultrafast processes that dominate liquid dynamics near the glass transition.

[Estimation of dietary fiber content of feedstuffs]. / Zur schätzung des Nahrungsfasergehaltes von Futtermitteln.

In a series of 8 concentrates, 18 roughages and 13 wet feedstuffs the interactions between different dietary fibre fractions were studied. In comparison to other analytical methods the crude fibre method (XF) did not allow a satisfactory estimation of the dietary fibre content (DF) of the experimental feedstuffs. In comparison to the NDF and the dietary fibre content and depending on the feedstuff, XF content was lowered by 2 to 3 times and 2 to 4 times, respectively. There was a surprisingly high correspondence between the contents of NDF and unsoluble dietary fibre for almost all feedstuffs. Highly significant statistical coherences could be observed between the different fibre fractions. It can be expected, that these correlations do not always follow a linear relationship, as could be observed in the regressions equations for NDF to DF and XF to ADF.

[Energy utilization by swine of nutritive fiber-rich by-products from the milling and food industry]. / Energetische Verwertung nahrungsfaserreicher Nebenprodukte aus der Müllerei- und Nahrungsmittelindustrie beim Schwein.

Growing pigs (from 20 to 80 kg body weight) were fed diets containing equal amounts of soybean, pea (pisum sativum), millet and barley hulls as well as a mixture of these fibre sources. The effects of these fibrous components on the digestibility of energy and nutrients were investigated. Although some rations had a similar nutrient composition, important differences in the digestibility of energy could be observed: e.g. soybean hulls and pea hulls had a similar content in crude fibre but differed in the digestibility of energy by a factor 1:2. The difference in the digestibility of energy was even more pronounced between the rations with soybean hulls and millet hulls (factor 1:11, respectively) although the crude fibre and ADF fibre content were similar. Therefore the magnitude of the difference in digestibility of energy shows a considerable variation between the fibre sources. This seems to be caused partially by differences in the chemical nature of the fibrous by-products. Soybean hulls and barley hulls proved to be very well suited for growing pigs (11.4 MJ DE/kg DM and 10.0 MJ DE/kg DM, respectively). The pea hulls showed a mean content of digestible energy (5.6 MJ DE/kg DM) whereas the millet hulls (1.1 MJ DE/kg DM) didn't contribute significantly to the energy supply of the pigs.