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.

Intravaginal and intracervical application of seminal plasma in in vitro fertilization or intracytoplasmic sperm injection treatment cycles--a double-blind, placebo-controlled, randomized pilot study

OBJECTIVE: To evaluate whether intravaginal application of seminal plasma at the time of follicle aspiration in IVF or intracytoplasmic sperm injection treatment cycles has the potential to increase pregnancy rate. To calculate the number of patients needed to achieve significance in a multicenter trial. DESIGN: Double-blind, placebo-controlled randomized pilot study. SETTING: University department of gynecological endocrinology and reproductive medicine. PATIENT(S): One hundred sixty-eight patients undergoing IVF or intracytoplasmic sperm injection treatment. INTERVENTION(S): Cryopreserved seminal plasma from the patient's partner or sodium chloride (placebo) was injected into the cervix and the posterior fornix of the vagina just after follicle aspiration. MAIN OUTCOME MEASURE(S): Clinical-pregnancy rate. RESULT(S): One hundred sixty-eight patients agreed to participate in the study. Participation was limited to one treatment cycle. Thirty-one patients (18%) were excluded from the study, mainly as a result of canceled embryo transfers. Seventy patients received placebo, and 67 received seminal plasma. The clinical-pregnancy rate was 25.7% (18/70) in the placebo group. The clinical-pregnancy rate in the seminal plasma group reached 37.3% (25/67), corresponding to a relative increase of 45%. CONCLUSION(S): Even though significance was not reached in this pilot study, the data suggest that seminal plasma has the potential to improve pregnancy rate. It is estimated that around 450 patients need to be recruited to reach significance in a multicenter study.

DNA methylation patterns at the IGF2-H19 locus in sperm of Swiss Landrace and Swiss Large White boars

DNA methylation patterns at the IGF2-H19 locus were investigated in sperm DNA from Swiss Landrace (SL) and Swiss Large White (LW) boars. The putative IGF2 differentially methylated regions (DMR) 0, 1 and 2, a quantitative trait nucleotide (QTN) region in the intron 3 and a CpG island in the intron 4 of the IGF2 gene as well as three regions around porcine CTCF binding sites within the H19 differentially methylated domain (DMD) were selected for the DNA methylation analysis. In both breeds putative IGF2 DMR0, 1, 2 and H19 DMD were hypermethylated. Significant differences in DNA methylation content were found between the two breeds in the two DMD regions proximal to the H19 gene. The IGF2 QTN region and the CpG island in the IGF2 intron 4 were hypomethylated in sperm DNA of both breeds. The methylation analysis revealed significantly more methylated CpG sites in the intron 4 of sperm from the LW breed than in that from SL. No difference was found in global DNA methylation between the two breeds. These results indicate differences in DNA methylation patterns between breeds and it remains to be established whether variation in DNA methylation patterns impacts on phenotypic traits.

Investigations into Velocity and Distance Perception Based on Different Types of Moving Sound Sources with Respect to Auditory Virtual Environments

The characteristics of moving sound sources have strong implications on the listener's distance perception and the estimation of velocity. Modifications of the typical sound emissions as they are currently occurring due to the tendency towards electromobility have an impact on the pedestrian's safety in road traffic. Thus, investigations of the relevant cues for velocity and distance perception of moving sound sources are not only of interest for the psychoacoustic community, but also for several applications, like e.g. virtual reality, noise pollution and safety aspects of road traffic. This article describes a series of psychoacoustic experiments in this field. Dichotic and diotic stimuli of a set of real-life recordings taken from a passing passenger car and a motorcycle were presented to test subjects who in turn were asked to determine the velocity of the object and its minimal distance from the listener. The results of these psychoacoustic experiments show that the estimated velocity is strongly linked to the object's distance. Furthermore, it could be shown that binaural cues contribute significantly to the perception of velocity. In a further experiment, it was shown that - independently of the type of the vehicle - the main parameter for distance determination is the maximum sound pressure level at the listener's position. The article suggests a system architecture for the adequate consideration of moving sound sources in virtual auditory environments. Virtual environments can thus be used to investigate the influence of new vehicle powertrain concepts and the related sound emissions of these vehicles on the pedestrians' ability to estimate the distance and velocity of moving objects.

Pulmonary venous flow velocity patterns in 404 individuals without cardiovascular disease

OBJECTIVE To determine the pulmonary venous flow velocity (PVFV) values in a large normal population. DESIGN Prospective study in consecutive individuals. SETTING University hospital. METHODS Among 404 normal individuals, the flow velocity pattern in the right upper pulmonary vein was recorded in 315 subjects using transthoracic echocardiography, and in both upper pulmonary veins in 100 subjects using transoesophageal echocardiography. Subjects were divided into five age groups. The PVFV values were compared between transthoracic and transoesophageal echocardiography within the age groups, and intraindividually between the right and left upper pulmonary veins in transoesophageal echocardiography. RESULTS Normal PVFV values for the right upper pulmonary vein in transthoracic and transoesophageal echocardiography are presented. The duration of flow reversal at atrial contraction was overestimated using transthoracic echocardiography (mean (SD): 96 (21) ms in transoesophageal echocardiography, 120 (28) ms in transthoracic echocardiography, p < 0.0001). Systolic to diastolic peak flow velocity ratio (S:D) increased earlier with advancing age with transoesophageal echocardiography than with transthoracic echocardiography. Similar results were found for the corresponding time-velocity integrals. Data from the left and right upper pulmonary veins differed with respect to onset and deceleration of flow velocities, but not for flow durations or peak velocities. CONCLUSIONS Normal PVFV values generally show a wide range. The data presented will be of value in assessing left ventricular diastolic function and mitral regurgitation using the PVFV pattern.

Chloride channels in myotonia congenita assessed by velocity recovery cycles

Introduction: Myotonia congenita (MC) is caused by congenital defects in the muscle chloride channel CLC-1. This study used muscle velocity recovery cycles (MVRCs) to investigate how membrane function is affected. Methods: MVRCs and responses to repetitive stimulation were compared between 18 patients with genetically confirmed MC (13 recessive, 7 dominant) and 30 age-matched normal controls. Results: MC patients exhibited increased early supernormality, but treatment with sodium channel blockers prevented this. After multiple conditioning stimuli, late supernormality was enhanced in all MC patients, indicating delayed repolarization. These abnormalities were similar between the MC subtypes, but recessive patients showed a greater drop in amplitude during repetitive stimulation. Discussion: MVRCs indicate that chloride conductance only becomes important when muscle fibers are depolarized. The differential responses to repetitive stimulation suggest that in dominant MC the affected chloride channels are activated by strong depolarization, consistent with a positive shift of the CLC-1 activation curve. © 2013 Wiley Periodicals, Inc.

In search of epigenetic marks in testes and sperm cells of differentially fed boars

In search of transmittable epigenetic marks we investigated gene expression in testes and sperm cells of differentially fed F0 boars from a three generation pig feeding experiment that showed phenotypic differences in the F2 generation. RNA samples from 8 testes of boars that received either a diet enriched in methylating micronutrients or a control diet were analyzed by microarray analysis. We found moderate differential expression between testes of differentially fed boars with a high FDR of 0.82 indicating that most of the differentially expressed genes were false positives. Nevertheless, we performed a pathway analysis and found disparate pathway maps of development_A2B receptor: action via G-protein alpha s, cell adhesion_Tight junctions and cell adhesion_Endothelial cell contacts by junctional mechanisms which show inconclusive relation to epigenetic inheritance. Four RNA samples from sperm cells of these differentially fed boars were analyzed by RNA-Seq methodology. We found no differential gene expression in sperm cells of the two groups (adjusted P-value>0.05). Nevertheless, we also explored gene expression in sperm by a pathway analysis showing that genes were enriched for the pathway maps of bacterial infections in cystic fibrosis (CF) airways, glycolysis and gluconeogenesis p.3 and cell cycle_Initiation of mitosis. Again, these pathway maps are miscellaneous without an obvious relationship to epigenetic inheritance. It is concluded that the methylating micronutrients moderately if at all affects RNA expression in testes of differentially fed boars. Furthermore, gene expression in sperm cells is not significantly affected by extensive supplementation of methylating micronutrients and thus RNA molecules could not be established as the epigenetic mark in this feeding experiment.