Parametric estimation of pulse arrival time: a robust approach to pulse wave velocity.

Pulse wave velocity (PWV) is a surrogate of arterial stiffness and represents a non-invasive marker of cardiovascular risk. The non-invasive measurement of PWV requires tracking the arrival time of pressure pulses recorded in vivo, commonly referred to as pulse arrival time (PAT). In the state of the art, PAT is estimated by identifying a characteristic point of the pressure pulse waveform. This paper demonstrates that for ambulatory scenarios, where signal-to-noise ratios are below 10 dB, the performance in terms of repeatability of PAT measurements through characteristic points identification degrades drastically. Hence, we introduce a novel family of PAT estimators based on the parametric modeling of the anacrotic phase of a pressure pulse. In particular, we propose a parametric PAT estimator (TANH) that depicts high correlation with the Complior(R) characteristic point D1 (CC = 0.99), increases noise robustness and reduces by a five-fold factor the number of heartbeats required to obtain reliable PAT measurements.

Ageing Prisoners' Disease Burden: Is Being Old a Better Predictor than Time Served in Prison?

Background: The number of older prisoners entering and ageing in prison has increased in the last few decades. Ageing prisoners pose unique challenges to the prison administration as they have differentiated social, custodial and healthcare needs than prisoners who are younger and relatively healthier. Objective: The goal of this study was to explore and compare the somatic disease burden of old and young prisoners, and to examine whether it can be explained by age group and/or time served in prison. Methods: Access to prisoner medical records was granted to extract disease and demographic information of older (>50 years) and younger (≤49 years) prisoners in different Swiss prisons. Predictor variables included the age group and the time spent in prison. The dependent variable was the total number of somatic diseases as reported in the medical records. Results were analysed using descriptive statistics and a negative binomial model. Results: Data of 380 male prisoners from 13 different prisons in Switzerland reveal that the mean ages of older and younger prisoners were 58.78 and 34.26 years, respectively. On average, older prisoners have lived in prison for 5.17 years and younger prisoners for 2.49 years. The average total number of somatic diseases reported by older prisoners was 2.26 times higher than that of prisoners below 50 years of age (95% CI 1.77-2.87, p < 0.001). Conclusion: This study is the first of its kind to capture national disease data of prisoners with a goal of comparing the disease burden of older and younger prisoners. Study findings indicate that older inmates suffer from more somatic diseases and that the number of diseases increases with age group. Results clearly illustrate the poorer health conditions of those who are older, their higher healthcare burden, and raises questions related to the provision of healthcare for inmates growing old in prison. © 2014 S. Karger AG, Basel.

Organisation structurale du noyau et de microtubules de cellules de mammifères observés par cryo-microscopie électronique de sections hydratées

RESUME L'architecture nucléaire ainsi que l'ultrastructure des microtubules ont été abondamment étudiées par des méthodes cytochimiques utilisant des échantillons fixés chimiquement, enrobés dans des résines ou fixés à basse température. Les échantillons fixés à basse température pouvant aussi avoir été substitués, déshydratés et enrobés dans des résines pour la plupart hydrophiles. Ici, nous avons étendu ces études en utilisant la microscopie électronique effectuée sur des sections hydratées (CEMOVIS) permettant d'observer les échantillons dans un état le plus proche de leur état natif. De plus, nous avons effectué de la tomographie électronique sur des sections hydratées (TOVIS) afin d'obtenir une vision tridimensionnelle de : 1) la périphérie du noyau et de la région périchromatinienne et 2) de la lumière des microtubules. Concernant l'architecture nucléaire Nos observations montrent que le nucléole et la chromatine condensée sont facilement visualisés grâce à la texture spécifique qu'ils arborent. Au contraire, la visualisation de domaines nucléaires importants et spécialement ceux qui contiennent des ribonucléoprotéines, est rendue difficile, à cause du faible contraste qui caractérise l'espace interchromatinien. Ceci est essentiellement dû à la quantité d'information présente dans le volume de la section qui semble être superposée, lorsque observée sur des micrographies en deux dimensions. La tomographie nous a permis de mieux visualiser les différentes régions du noyau. Les mottes de chromatine condensée sont décorées à leur périphérie (région périchromatinienne), par nombre de fibrilles et granules. Des tunnels d'espace interchromatinien sont occasionnellement observés en train de traverser des régions de chromatine condensée favorisant l'accès aux pores nucléaires. Enfin, nous avons pu, au niveau d'un pore unique, observer la plupart des structures caractéristiques du complexe de pore nucléaire. Concernant l'ultrastructure des microtubules: Nous avons démontré que la polarité d'un microtubule observé in situ en section transversale, par CEMOVIS, est directement déduite de l'observation de la chiralité de ses protofilaments. Cette chiralité, a été établie précédemment comme étant liée à la morphologie des sous unités de tubuline. La tomographie électronique effectuée sur des sections hydratées, nous a permis d'observer les microtubules dans leur contexte cellulaire avec une résolution suffisante pour visualiser des détails moléculaires, comme les monomères de tubuline. Ainsi, des molécules n'ayant pas encore été caractérisées, ont été observées dans la lumière des microtubules. Ces observations ont été effectuées autant sur des cellules observées en coupe par CEMOVIS que sur des cellules congelées dans leur totalité par immersion dans un bain d'éthane liquide. Enfin, nous avons montré que les microtubules étaient aussi de formidables objets, permettant une meilleure compréhension des artéfacts de coupe occasionnés lors de la préparation des échantillons par CEMOVIS. Les buts des études qui seront menées â la suite de ce travail seront de 1) essayer de localiser des domaines nucléaires spécifiques par des approches cytochimiques avant la congélation des cellules. 2) Appliquer des méthodes de moyennage afin d'obtenir un modèle tridimensionnel de la structure du complexe de pore nucléaire dans son contexte cellulaire. 3) Utiliser des approches biochimiques afin de déterminer la nature exacte des particules qui se trouvent dans la lumière des microtubules. ABSTRACT Nuclear architecture as well as microtubule ultrastructure have been extensively investigated by means of different methods of ultrastructural cytochemistry using chemically fixed and resin embedded samples or following cryofixation, cryosubstitution and embedding into various, especially partially hydrophilic resins. Here, we extend these studies using cryoelectron microscopy of vitreous sections (CEMOVIS) which allows one to observe the specimen as close as possible to its native state. Furthermore, we applied cryoelectron tomography of vitreous sections (TOVIS) in order to obtain athree-dimensional view of: 1) the nuclear periphery, and of the perichromatin region, and 2) the microtubule lumen. Concerning the nuclear architecture: Our observations show that nucleoli and condensed chromatin are well recognisable due to their specific texture. Conversely, the visualisation of other important nuclear domains, especially those containing ribonucleoproteins, is seriously hampered by a generally low contrast of the interchromatin region. This is mainly due to the plethora of information superposed in the volume of the section observed on two-dimensional micrographs. Cryoelectron tomography allowed us to better visualise nuclear regions. Condensed chromatin clumps are decorated on their periphery, the perichromatin region, by numerous fibrils and granules. Tunnels of interchromatin space can occasionally be found as crossing condensed chromatin regions, thus, allowing the access to nuclear pores. Finally, we were able to use TOVIS to directly distinguish most of the nuclear pore complex structures, at the level of a single pore. Concerning the microtubule ultrastructure: We have demonstrated that the polarity of across-sectioned microtubule observed in situ by CEMOVIS wás directly deducible from the visualisation of the tubulin protofiíaments' chirality. This chirality has been established before as related to the shape. of the tubulin subunits. Cryoelectron tomography allowed us to observe microtubules in their cellular context at a resolution sufficient to resolve molecular details such as their tubulin monomers. In this way, uncharacterized molecules were visualised in the microtubule lumen. These observations were made either on samples prepared by CEMOVIS or plunge freezing of whole cells. Finally, we have shown that microtubules are also relevant objects for the understanding of cutting artefacts, when performing CEMOVIS. The goals of our further studies will be to: 1) try to speciifically target different nuclear domains by cytochemical approaches in situ, prior to cryofixation. 2) Apply averaging methods in order to obtain a three-dimensional model of the nuclear pore complex at work, in its cellular context. 3) Use biochemical analysis combined in a second time to immunocytochemical approaches, to determine the exact nature of the microtubule's luminal particles.

Sense of time in children with Attention-Deficit/Hyperactivity Disorder (ADHD) : a comparative study

Parents of children with attention-deficit/hyperactivity disorder (ADHD) frequently report that their children have a poor sense of time. Several studies looking at the perception of time mentioned a form of temporal myopia. The present study investigates the sense of time in children with ADHD. Twenty-two French-speaking Swiss children with ADHD and 22 controls between the ages of 6 and 13 years were tested using a conventional time knowledge questionnaire and two Piagetian time conservation tasks. Parents were asked to complete the "It's about time" questionnaire. Better performance was observed in matched control group children than in children with ADHD on a conventional time knowledge questionnaire. For children under 10 years of age, the two Piagetian time conservation tasks were able to differentiate children with and without ADHD. Parents of ADHD children reported more frequently that their children had time-related difficulties in daily activities. This study suggests that children with ADHD take longer to develop several time-related abilities.

Estimation of time of death in relation to gastric contents

Introduction: Estimation of the time since death based on the gastric content is still a controversy subject. Many studies have been achieved leaving the same incertitude: the intra- and inter-individual variability. Aim: After a homicidal case where a specialized gastroenterologist was cited to estimate the time of death based on the gastric contents and his experience in clinical practice. Consequently we decided to make a review of the scientific literature to see if that method was more reliable nowadays. Material and methods: We chose articles from 1979 that describe the estimation of the gastric emptying rate according to several factors and the forensic articles about the estimation of the time of death in relation with the gastric content. Results: Most of the articles cited by the specialized gastroenterologist were studies about living healthy people and the effects of several factors (medication, supine versus upside-down position, body mass index or different type of food). Forensic articles frequently concluded that the estimation of the time since death by analyzing the gastric content can be used but not as the unique method. Conclusion: Estimation of the time since death by analyze of the gastric contents is a method that can be used nowadays. But it cannot be the only method as the inter- and intra-individual variability remains an important bias.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry and PCR-based rapid diagnosis of Staphylococcus aureus bacteraemia.

Effective empirical treatment is of paramount importance to improve the outcome of patients with Staphylococcus aureus bacteraemia. We aimed to evaluate a PCR-based rapid diagnosis of methicillin resistance (GeneXpert MRSA) after early detection of S. aureus bacteraemia using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Patients with a first episode of S. aureus bacteraemia identified using MALDI-TOF MS were randomized in a prospective interventional open study between October 2010 and August 2012. In the control group, antibiotic susceptibility testing was performed after MALDI-TOF MS identification on blood culture pellets. In the intervention group, a GeneXpert MRSA was performed after S. aureus identification. The primary outcome was the performance of GeneXpert MRSA directly on blood cultures. We then assessed the impact of early diagnosis of methicillin resistance on the empirical treatment. In all, 197 episodes of S. aureus bacteraemia were included in the study, of which 106 were included in the intervention group. Median time from MALDI-TOF MS identification to GeneXpert MRSA result was 97 min (range 25-250). Detection of methicillin resistance using GeneXpert MRSA had a sensitivity of 99% and a specificity of 100%. There was less unnecessary coverage of MRSA in the intervention group (17.1% versus 29.2%, p 0.09). GeneXpert MRSA was highly reliable in diagnosing methicillin resistance when performed directly on positive blood cultures. This could help to avoid unnecessary prescriptions of anti-MRSA agents and promote the introduction of earlier adequate coverage in unsuspected cases.

Documenting a time-bound, circular view of hierarchies: a microanalysis of parent-infant dyadic interaction.

This article presents a new theory that separates the levels of communication and relates them circularly, namely, by separating time from space/meaning variables. Documenting this proposition requires sequential microdescriptions--a far-out project in the field of family therapy. In an extensive study of clinical and nonclinical families, starting with available microanalytic data on nonverbal parent-infant dialogue, distinct time organizations have been found to modify the degree of circularity between the levels of interaction according to the observed types of engagement, that is, consensual, conflictual, and paradoxical. The double description of the dyad as a totality versus the dyad as a framing/developing organization imparts crucial information on how development proceeds in dyadic, co-evolutive systems, and presumably in larger ones too. In this perspective, a model is elaborated and then applied to a case description in our therapeutic consultation.

Niche dynamics in space and time.

Niche conservatism, the tendency of a species niche to remain unchanged over time, is often assumed when discussing, explaining or predicting biogeographical patterns. Unfortunately, there has been no basis for predicting niche dynamics over relevant timescales, from tens to a few hundreds of years. The recent application of species distribution models (SDMs) and phylogenetic methods to analysis of niche characteristics has provided insight to niche dynamics. Niche shifts and conservatism have both occurred within the last 100 years, with recent speciation events, and deep within clades of species. There is increasing evidence that coordinated application of these methods can help to identify species which likely fulfill one key assumption in the predictive application of SDMs: an unchanging niche. This will improve confidence in SDM-based predictions of the impacts of climate change and species invasions on species distributions and biodiversity.

Detection of live and antibiotic-killed bacteria by quantitative real-time PCR of specific fragments of ribosomal RNA

RÉSUMÉ Le but d'un traitement antimicrobien est d'éradiquer une infection bactérienne. Cependant, il est souvent difficile d'en évaluer rapidement l'efficacité en utilisant les techniques standard. L'estimation de la viabilité bactérienne par marqueurs moléculaires permettrait d'accélérer le processus. Ce travail étudie donc la possibilité d'utiliser le RNA ribosomal (rRNA) à cet effet. Des cultures de Streptococcus gordonii sensibles (parent Wt) et tolérants (mutant Tol 1) à l'action bactéricide de la pénicilline ont été exposées à différents antibiotiques. La survie bactérienne au cours du temps a été déterminée en comparant deux méthodes. La méthode de référence par compte viable a été comparée à une méthode moléculaire consistant à amplifier par PCR quantitative en temps réel une partie du génome bactérien. La cible choisie devait refléter la viabilité cellulaire et par conséquent être synthétisée de manière constitutive lors de la vie de la bactérie et être détruite rapidement lors de la mort cellulaire. Le choix s'est porté sur un fragment du gène 16S-rRNA. Ce travail a permis de valider ce choix en corrélant ce marqueur moléculaire à la viabilité bactérienne au cours d'un traitement antibiotique bactéricide. De manière attendue, les S. gordonii sensibles à la pénicilline ont perdu ≥ 4 log10 CFU/ml après 48 heures de traitement par pénicilline alors que le mutant tolérant Tol1 en a perdu ≥ 1 log10 CFU/ml. De manière intéressant, la quantité de marqueur a augmenté proportionnellement au compte viable durant la phase de croissance bactérienne. Après administration du traitement antibiotique, l'évolution du marqueur dépendait de la capacité de la bactérie à survivre à l'action de l'antibiotique. Stable lors du traitement des souches tolérantes, la quantité de marqueur détectée diminuait de manière proportionnelle au compte viable lors du traitement des souches sensibles. Cette corrélation s'est confirmée lors de l'utilisation d'autres antibiotiques bactéricides. En conclusion, l'amplification par PCR du RNA ribosomal 16S permet d'évaluer rapidement la viabilité bactérienne au cours d'un traitement antibiotique en évitant le recours à la mise en culture dont les résultats ne sont obtenus qu'après plus de 24 heures. Cette méthode offre donc au clinicien une évaluation rapide de l'efficacité du traitement, particulièrement dans les situations, comme le choc septique, où l'initiation sans délai d'un traitement efficace est une des conditions essentielles du succès thérapeutique. ABSTRACT Assessing bacterial viability by molecular markers might help accelerate the measurement of antibiotic-induced killing. This study investigated whether ribosomal RNA (rRNA) could be suitable for this purpose. Cultures of penicillin-susceptible and penicillin-tolerant (Tol1 mutant) Streptococcus gordonii were exposed to mechanistically different penicillin and levofloxacin. Bacterial survival was assessed by viable counts, and compared to quantitative real-time PCR amplification of either the 16S-rRNA genes (rDNA) or the 16S rRNA, following reverse transcription. Penicillin-susceptible S. gordonii lost ≥ 4 log10 CFU/ml of viability over 48 h of penicillin treatment. In comparison, the Toll mutant lost ≤ 1 log10 CFU/ml. Amplification of a 427-base fragment of 16S rDNA yielded amplicons that increased proportionally to viable counts during bacterial growth, but did not decrease during drug-induced killing. In contrast, the same 427-base fragment amplified from 16S rDNA paralleled both bacterial growth and drug-induced killing. It also differentiated between penicillin-induced killing of the parent and the Toll mutant (≥4 log10 CFU/ml and ≤1 lo10 CFU/ml, respectively), and detected killing by mechanistically unrelated levofloxacin. Since large fragments of polynucleotides might be degraded faster than smaller fragments the experiments were repeated by amplifying a 119-base region internal to the origina1 427-base fragment. The amount of 119-base amplicons increased proportionally to viability during growth, but remained stable during drug treatment. Thus, 16S rRNA was a marker of antibiotic-induced killing, but the size of the amplified fragment was critical to differentiate between live and dead bacteria.

Chromosomal rearrangements and gene flow over time in an inter-specific hybrid zone of the Sorex araneus group.

Most hybrid zones have existed for hundreds or thousands of years but have generally been observed for only a short time period. Studies extending over periods long enough to track evolutionary changes in the zones or assess the ultimate outcome of hybridization are scarce. Here, we describe the evolution over time of the level of genetic isolation between two karyotypically different species of shrews (Sorex araneus and Sorex antinorii) at a hybrid zone located in the Swiss Alps. We first evaluated hybrid zone movement by contrasting patterns of gene flow and changes in cline parameters (centre and width) using 24 microsatellite loci, between two periods separated by 10 years apart. Additionally, we tested the role of chromosomal rearrangements on gene flow by analysing microsatellite loci located on both rearranged and common chromosomes to both species. We did not detect any movement of the hybrid zone during the period analysed, suggesting that the zone is a typical tension zone. However, the gene flow was significantly lower among the rearranged than the common chromosomes for the second period, whereas the difference was only marginally significant for the first period. This further supports the role of chromosomal rearrangements on gene flow between these taxa.

Real-time recording of circadian liver gene expression in freely moving mice reveals the phase-setting behavior of hepatocyte clocks.

The mammalian circadian timing system consists of a master pacemaker in the suprachiasmatic nucleus (SCN) in the hypothalamus, which is thought to set the phase of slave oscillators in virtually all body cells. However, due to the lack of appropriate in vivo recording technologies, it has been difficult to study how the SCN synchronizes oscillators in peripheral tissues. Here we describe the real-time recording of bioluminescence emitted by hepatocytes expressing circadian luciferase reporter genes in freely moving mice. The technology employs a device dubbed RT-Biolumicorder, which consists of a cylindrical cage with reflecting conical walls that channel photons toward a photomultiplier tube. The monitoring of circadian liver gene expression revealed that hepatocyte oscillators of SCN-lesioned mice synchronized more rapidly to feeding cycles than hepatocyte clocks of intact mice. Hence, the SCN uses signaling pathways that counteract those of feeding rhythms when their phase is in conflict with its own phase.