Gemfibrozil and its oxidative metabolites: quantification of aglycones, acyl glucuronides, and covalent adducts in samples from preclinical and clinical kinetic studies

A gradient reversed-phase HPLC analysis for the direct measurement of gemfibrozil (GEM) and four oxidative metabolites in plasma and urine of humans and in tissue homogenates of rats was developed. The corresponding acyl glucuronides and the covalently bound protein adducts (in protein precipitates) were determined after liberation from the respective conjugates via alkaline hydrolysis. The limits of detection for the covalent adducts in human plasma are: 10 ng ml⁻¹ (GEM), 20 ng ml⁻¹ (M1), 0.5 ng ml⁻¹ (M2, M4), and 5 ng ml⁻¹ (M3). The method was validated with respect to selectivity, recovery, linearity, precision, and accuracy. It has been applied to the analysis of preclinical and clinical studies. Pharmacokinetic profiles of gemfibrozil, its metabolites, and covalent adducts in human plasma and rat tissue homogenates are given.     

Diagnostic Support for Selected Paediatric Pulmonary Diseases Using Answer-Pattern Recognition in Questionnaires Based on Combined Data Mining Applications—A Monocentric Observational Pilot Study

Background

Clinical symptoms in children with pulmonary diseases are frequently non-specific. Rare diseases such as primary ciliary dyskinesia (PCD), cystic fibrosis (CF) or protracted bacterial bronchitis (PBB) can be easily missed at the general practitioner (GP).

Objective

To develop and test a questionnaire-based and data mining-supported tool providing diagnostic support for selected pulmonary diseases.

Methods

First, interviews with parents of affected children were conducted and analysed. These parental observations during the pre-diagnostic time formed the basis for a new questionnaire addressing the parents’ view on the disease. Secondly, parents with a sick child (e.g. PCD, PBB) answered the questionnaire and a data base was set up. Finally, a computer program consisting of eight different classifiers (support vector machine (SVM), artificial neural network (ANN), fuzzy rule-based, random forest, logistic regression, linear discriminant analysis, naive Bayes and nearest neighbour) and an ensemble classifier was developed and trained to categorise any given new questionnaire and suggest a diagnosis. For estimating the diagnostic accuracy, we applied ten-fold stratified cross validation.

Results

All questionnaires of patients suffering from CF, asthma (AS), PCD, acute bronchitis (AB) and the healthy control group were correctly diagnosed by the fusion algorithm. For the pneumonia (PM) group 19/21 (90.5%) and for the PBB group 17/18 (94.4%) correct diagnoses could be reached. The program detected the correct diagnoses with an overall sensitivity of 98.8%. Receiver operating characteristics (ROC) analyses confirmed the accuracy of this diagnostic tool. Case studies highlighted the applicability of the tool in the daily work of a GP.

Conclusion

For children with symptoms of pulmonary diseases a questionnaire-based diagnostic support tool using data mining techniques exhibited good results in arriving at diagnostic suggestions. In the hands of a doctor, this tool could be of value in arousing awareness for rare pulmonary diseases such as PCD or CF.     

A Likelihood-Based Approach to Identifying Contaminated Food Products Using Sales Data: Performance and Challenges

Foodborne disease outbreaks of recent years demonstrate that due to increasingly interconnected supply chains these type of crisis situations have the potential to affect thousands of people, leading to significant healthcare costs, loss of revenue for food companies, and—in the worst cases—death. When a disease outbreak is detected, identifying the contaminated food quickly is vital to minimize suffering and limit economic losses. Here we present a likelihood-based approach that has the potential to accelerate the time needed to identify possibly contaminated food products, which is based on exploitation of food products sales data and the distribution of foodborne illness case reports. Using a real world food sales data set and artificially generated outbreak scenarios, we show that this method performs very well for contamination scenarios originating from a single “guilty” food product. As it is neither always possible nor necessary to identify the single offending product, the method has been extended such that it can be used as a binary classifier. With this extension it is possible to generate a set of potentially “guilty” products that contains the real outbreak source with very high accuracy. Furthermore we explore the patterns of food distributions that lead to “hard-to-identify” foods, the possibility of identifying these food groups a priori, and the extent to which the likelihood-based method can be used to quantify uncertainty. We find that high spatial correlation of sales data between products may be a useful indicator for “hard-to-identify” products.     

An Analysis of the Alleged Skeletal Remains of Carin G?ring

In 1991, treasure hunters found skeletal remains in an area close to the destroyed country residence of former Nazi leader Hermann Göring in northeastern Berlin. The remains, which were believed to belong to Carin Göring, who was buried at the site, were examined to determine whether it was possible to make a positive identification. The anthropological analysis showed that the remains come from an adult woman. The DNA analysis of several bone elements showed female sex, and a reference sample from Carin''s son revealed mtDNA sequences identical to the remains. The profile has one nucleotide difference from the Cambridge reference sequence (rCRS), the common variant 263G. A database search resulted in a frequency of this mtDNA sequence of about 10% out of more than 7,000 European haplotypes. The mtDNA sequence found in the ulna, the cranium and the reference sample is, thus, very common among Europeans. Therefore, nuclear DNA analysis was attempted. The remains as well as a sample from Carin''s son were successfully analysed for the three nuclear markers TH01, D7S820 and D8S1179. The nuclear DNA analysis of the two samples revealed one shared allele for each of the three markers, supporting a mother and son relationship. This genetic information together with anthropological and historical files provides an additional piece of circumstantial evidence in our efforts to identify the remains of Carin Göring.     

Restored fitness leads to long-term persistence of resistant Bacteroides strains in the human intestine

Acquired antibiotic resistance typically confers a cost to the bacteria, but these costs can be reduced by genetic compensation over time. The fitness of two Bacteroides thetaiotaomicron clones consecutively isolated in vivo was studied using an in vitro pair-wise competition method. The isolates derived from faecal samples of two clindamycin-exposed healthy volunteers and the two B. thetaiotaomicron clone types could be followed up to 18 months in these two subjects. The two clones were originally susceptible to clindamycin and lacked erm genes; however, after 7 days of clindamycin administration they carried the erm (erythromycin methylase)(G) or (F) gene, respectively, and expressed phenotypic clindamycin resistance. The initial cost of acquired resistance was high as seen in the in vitro pair-wise competition experiments. At 2 weeks post-administration, no growth disadvantage was detected for isolates of either of the two clones in the in vitro experiments and this regained fitness remained for isolates collected up to 18 months. Competition analysis of an in vitro isolated erm(G) positive transconjugant also demonstrated an initial reduction of fitness that was restored over time. The results indicate that the biological cost associated with a resistance gene can rapidly be compensated during in vivo growth. Thus, once the resistant clone has gained its resistance determinant it will be difficult to eliminate.     

Adenovirus type 37 uses sialic acid as a cellular receptor

Two cellular receptors for adenovirus, coxsackievirus-adenovirus receptor (CAR) and major histocompatibility complex class I (MHC-I) alpha2, have recently been identified. In the absence of CAR, MHC-I alpha2 has been suggested to serve as a cellular attachment protein for subgenus C adenoviruses, while members from all subgenera except subgenus B have been shown to interact with CAR. We have found that adenovirus type 37 (Ad37) attachment to CAR-expressing CHO cells was no better than that to CHO cells lacking CAR expression, suggesting that CAR is not used by Ad37 during attachment. Instead, we have identified sialic acid as a third adenovirus receptor moiety. First, Ad37 attachment to both CAR-expressing CHO cells and MHC-I alpha2-expressing Daudi cells was sensitive to neuraminidase treatment, which eliminates sialic acid on the cell surface. Second, Ad37 attachment to sialic acid-expressing Pro-5 cells was more than 10-fold stronger than that to the Pro-5 subline Lec2, which is deficient in sialic acid expression. Third, neuraminidase treatment of A549 cells caused a 60% decrease in Ad37 replication in a fluorescent-focus assay. Moreover, the receptor sialoconjugate is most probably a glycoprotein rather than a ganglioside, since Ad37 attachment to sialic acid-expressing Pro-5 cells was sensitive to protease treatment. Ad37 attachment to Pro-5 cells occurs via alpha(2-->3)-linked sialic acid saccharides rather than alpha(2-->6)-linked ones, since (i) alpha(2-->3)-specific but not alpha(2-->6)-specific lectins blocked Ad37 attachment to Pro-5 cells and (ii) pretreatment of Pro-5 cells with alpha(2-->3)-specific neuraminidase resulted in decreased Ad37 binding. Taken together, these results suggest that, unlike Ad5, Ad37 makes use of alpha(2-->3)-linked sialic acid saccharides on glycoproteins for entry instead of using CAR or MHC-I alpha2.     

Perceptual distance and the moon illusion

The elevated moon usually appears smaller than the horizon moon of equal angular size. This is the moon illusion. Distance cues may enable the perceptual system to place the horizon moon at an effectively greater distance than the elevated moon, thus making it appear as larger. This explanation is related to the size-distance invariance hypothesis. However, the larger horizon moon is usually judged as closer than the smaller zenith moon. A bias to expect an apparently large object to be closer than a smaller object may account for this conflict. We designed experiments to determine if unbiased sensitivity to illusory differences in the size and distance of the moon (as measured by d') is consistent with SDIH. A moon above a 'terrain' was compared in both distance and size to an infinitely distant moon in empty space (the reduction moon). At a short distance the terrain moon was adjudged as both closer and smaller than the reduction moon. But these differences could not be detected at somewhat greater distances. At still greater distances the terrain moon was perceived as both more distant and larger than the reduction moon. The distances at which these transitions occurred were essentially the same for both distance and size discrimination tasks, thus supporting SDIH.     

Toward a Computer Assisted Analysis of NOESY Spectra: A Multivariate Data Analysis of an RNA NOESY Spectrum

Abstract

A multivariate data-representation of a portion of the ¹H-NOESY spectrum of an RNA octamer duplex was used to explore the possibility of using Principal Component Analysis and Partial Least Squares Discrimination for pattern recognition. In this case, it is found that the methods can: (i) distinguish slices containing signal from those containing only noise, (ii) locate slices containing overlapping signals, and (iii) in some cases to segregate slices with unique aspects such as those from terminal nucleotides, overlapping signals, purine-H8, pyrimidine-H6 and adenine-H2 containing slices. These properties can easily be included in a scheme to automate spectral analysis. The formulation described here does not distinguish patterns needed to automate sequential assignment of resonances in NOESY spectra of RNA.     

Identity and typification of Navicula hasta (Bacillariophyceae)

The name Navicula hasta is regularly applied to large, heavily silicified Navicula specimens with lanceolate outlines, protracted ends, and relatively coarse, radiate, and lineolate striae that are more irregularly spaced around the central area. As such, Navicula hasta has been reported from numerous localities such as brackish water fossil sediments, oligotrophic ancient lakes and postglacial lakes. When the data for distribution of Navicula hasta are summarized, this species appears to be geographically and temporally widespread with a broad range of ecologic tolerances. Published reports for size range show that diatomists during the last century have differing concepts of the species starting with the disagreement between the protologue and one of the figures given by Pantocsek. Furthermore, an informal ‘type’ of Navicula hasta reported in 1980 does not match the protologue and is not unambiguously based on material Pantocsek had in his hands when describing his new species. We studied published reports of Navicula hasta and investigated material reported to contain Navicula hasta and its allies from the type locality (Köpecz), one of the fossil deposits reported to contain N. hasta (Bodos) and from ancient and other younger lakes worldwide. From our analyses, we document the variation and underappreciated diversity within the Navicula hasta group and set the stage for formal recognition of new species in subsequent papers. Herein, we formally propose a lectotype from among the original illustrations and designate an epitype for Navicula hasta based on Pantocsek's Köpecz material. Additionally, two new species, Navicula krenneri spec. nov. and Navicula pseudohasta spec. nov. are described and a lectotype of Navicula superhasta Lange‐Bertalot and Metzeltin is proposed.