Right ventricular remodeling and dysfunction with subsequent annular dilatation and tethering as a mechanism of isolated tricuspid regurgitation.

PubMed

Seo, Hye-Sun; Ha, Jong-Won; Moon, Jae Youn; Choi, Eui-Young; Rim, Se-Joong; Jang, Yangsoo; Chung, Namsik; Shim, Won-Heum; Cho, Seung-Yun; Kim, Sung Soon

2008-10-01

Secondary tricuspid regurgitation (TR) as a result of pulmonary hypertension and/or left-sided heart disease is caused by tricuspid valve (TV) annular dilatation and tethering of the tricuspid leaflet after right ventricular (RV) dilatation. However, the mechanism of isolated TR without significant pulmonary hypertension remains unknown. The present study investigated the RV function and TV deformations in patients with isolated TR to find out the mechanism and etiology of the disease. Twelve patients with isolated, severe TR were included. RV area, volume, ejection fraction (EF), tenting distance and tenting area were measured. These parameters were compared with 12 age-and gender-matched controls and 12 patients with secondary TR. The cause of isolated TR was incomplete coaptation associated with annular dilatation without other problems. Compared with the controls, RV end-diastolic volumes and annular diameters were significantly larger and RVEF was significantly lower in patients with isolated TR. Tenting area and tenting distance were also significantly higher. However, there were no significant differences in these parameters between patients with isolated and secondary TR. Isolated TR was associated with RV remodeling, systolic dysfunction and resultant annular dilatation and tethering of tricuspid leaflets.

The effect of mydriasis from phenylephrine on corneal shape.

PubMed

Huang, Ronnie Y C; Lam, Andrew K C

2007-01-01

A previous study reported that pharmacologically-dilated pupils changed the corneal shape. Researchers used mydriatic agents with significant cycloplegic effect. The current study investigates the effect of mydriasis on corneal shape using phenylephrine alone, where phenylephrine has minimal effect on the accommodative system and whether corneal topography can be done after pupil dilation. Forty-four young healthy subjects with one eye randomly selected for mydriasis were used in this study. Twenty-two received one drop of 2.5% phenylephrine (group 1); the other 22 subjects had one drop of 0.4% benoxinate instilled prior to the application of 2.5% phenylephrine (group 2). They were matched for age and refractive error. Anterior chamber depth, pupil size and corneal parameters were compared before and after mydriasis. The corneal parameters included best-fit sphere (BFS), surface asymmetry index (SAI), surface regularity index (SRI) and the axial and tangential powers in the form of flattest and steepest powers, and in the form of M, J(0), and J(45) vector presentation. Group 1 and group 2 subjects had similar pre-mydriatic baseline ocular parameters. The mean (+/- SD) pupil dilation was 1.24 +/- 0.59 mm for group 1 and 1.80 +/- 0.95 mm for group 2. The dilation was significantly larger in group 2 (unpaired t-tests: t = 2.36, p = 0.02). There were no significant changes in corneal parameters from mydriasis in either group. Previous investigations used mydriatic agents, which affected not only the pupil size but also accommodation. The current study found that mydriasis from phenylephrine, with minimal effect on accommodation, did not result in significant corneal alteration, and corneal topography can be measured after pupil dilation with phenylephrine.

Eye Tracking and Pupillometry are Indicators of Dissociable Latent Decision Processes

PubMed Central

Cavanagh, James F.; Wiecki, Thomas V.; Kochar, Angad; Frank, Michael J.

2014-01-01

Can you predict what someone is going to do just by watching them? This is certainly difficult: it would require a clear mapping between observable indicators and unobservable cognitive states. In this report we demonstrate how this is possible by monitoring eye gaze and pupil dilation, which predict dissociable biases during decision making. We quantified decision making using the Drift Diffusion Model (DDM), which provides an algorithmic account of how evidence accumulation and response caution contribute to decisions through separate latent parameters of drift rate and decision threshold, respectively. We used a hierarchical Bayesian estimation approach to assess the single trial influence of observable physiological signals on these latent DDM parameters. Increased eye gaze dwell time specifically predicted an increased drift rate toward the fixated option, irrespective of the value of the option. In contrast, greater pupil dilation specifically predicted an increase in decision threshold during difficult decisions. These findings suggest that eye tracking and pupillometry reflect the operations of dissociated latent decision processes. PMID:24548281

Dilations of anastomotic strictures over time after repair of esophageal atresia.

PubMed

Stenström, Pernilla; Anderberg, Magnus; Börjesson, Anna; Arnbjörnsson, Einar

2017-02-01

Anastomotic strictures commonly occur in patients undergoing surgery for esophageal atresia (EA). The primary aim of this study was to determine the age distribution of dilation procedures for anastomotic strictures over the patient's childhood after reconstruction of EA. The secondary aim was to evaluate the effect of postoperative proton pump inhibitors (PPIs) on the frequency of dilations. This observational study was conducted at a single tertiary center of pediatric surgery. The times that dilations of strictures were performed were assessed during three study periods: 1983-1995, 2001-2009, and 2010-2014. PPIs were not used during the first period, and then, respectively, for 3 and 12 months postoperatively. The indications for dilation were signs of obstruction and/or radiological signs of stricture. A total of 131 children underwent esophageal reconstruction, and of those, 60 (46%) required at least 1 dilation procedure for strictures. There were no differences in the frequencies of dilation procedures between the three study periods (28/66, 18/32 and 14/33, respectively; P = 0.42). The overall median number of dilations per patient was 3 (range 1-21) with no differences between the study periods. The differences between ages at which the first dilation was performed during each study period were significant, as follows: 7, 2, and 8 months, respectively (P = 0.03). Fiftyone percent of all dilation procedures were performed during the first year of life, 16% during the second year, and 33% during years 2-15. Four children (2%) underwent >12 dilations. The first year of life was the time of greatest need for dilation of AS after reconstruction of EA; however, dilations were also performed several years later. PPIs did not affect the frequency of dilations during the first year of life.

Contrast enema as a guide for senna-based laxatives in managing overflow retentive stool incontinence in pediatrics.

PubMed

Radwan, Ahmed Bassiuony; El-Debeiky, Mohammed Soliman; Abdel-Hay, Sameh

2015-08-01

Overflow retentive stool incontinence (ORSI) is secondary to constipation and fecal loading. In our study, the dose and duration of senna-based laxatives (SBL) treatment to achieve full defecatory control will be examined for possible correlation with new parameters measured from the initial contrast enema. Initially, an observational study was conducted prospectively on a group of patient with ORSI to define the optimum dose of SBL to achieve full defecatory control with measurement of six parameters in the initial contrast enema (level of colonic dilatation, recto-anal angle, ratio of maximal diameter of dilated colon to last lumbar spine, ratio of maximum diameter of dilated colon to normal descending colon, immediate and after 24-h post-evacuation residual contrast). The result was analyzed statistically to reach a correlation between the radiological data and prescribed dose. Over 2 and half years, 72 patients were included in the study; their mean age was 6.3 ± 3.33 years. The mean effective starting dose of SBL was 57 ± 18.13 mg/day and the mean effective ending dose was 75 ± 31.68 mg/day. Time lapsed till full defecatory control ranged from 1 to 16 weeks. Statistical correlation revealed that mean effective ending dose of SBL treatment significantly increased with higher levels of colonic dilatation. A weak positive correlation was found for both the mean effective starting and ending doses with the ratio of maximum colonic diameter to last lumbar spine and descending colonic diameters ratio. Senna-based laxatives are effective treatment for overflow retentive stool incontinence and their doses can be adjusted initially depending on the analysis of the radiological data.

The effect of pharmacologic pupillary dilatation on anterior segment parameters in patients with exfoliation syndrome.

PubMed

Mocan, Mehmet Cem; Ustunel, Saim; Dikmetas, Ozlem; Bozkurt, Banu; Irkec, Murat

2014-01-01

The purpose of this study was to evaluate the effect of pharmacologic pupillary dilatation on anterior chamber depth (ACD) and anterior chamber angle (ACA) in eyes with exfoliation syndrome (XFS). Thirty-six eyes of 36 patients with XFS were evaluated with slit-lamp examination, Goldmann applanation tonometry and ultrasound biomicroscopy (UBM) under standard light conditions. Primary outcome parameters were defined as the change in ACD and ACA measured before and 40 min after instillation of a single drop of either 1% cyclopentolate (Group I; n=12), 2.5% phenylephrine (Group II; n=12) or 1% tropicamide (Group III; n=12). Change in intraocular pressure (IOP) during the same time interval was included as a secondary outcome measure. The average predilatation ACD, ACA and IOP values in the study subjects were 2.54±0.40 mm, 27.9±6.3° and 14.9±3.1 mmHg, respectively. There were no significant differences in the mean age (p=0.461), the female/male ratio (p=0.232), baseline ACD (p=0.841), ACA (p=0.761) or IOP (p=0.070) within the three groups. Differences in dilation induced changes in ACD (p=0.108), ACA (p=0.636) and IOP (p=0.160) between the three groups were not statistically significant. Pupillary dilatation with a single drop of 1.0% cyclopentolate, 2.5% phenylephrine or 1% tropicamide is not associated with shallowing of the anterior chamber or narrowing of the ACA in patients with XFS who present with open angles. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Stress and Dilatancy Relation of Methane Hydrate Bearing Sand with Various Fines Content

NASA Astrophysics Data System (ADS)

Hyodo, M.

2016-12-01

This study presents an experimental and numerical study on the shear behaviour of methane hydrate bearing sand with variable confining pressures and methane hydrate saturations. A representative grading curve of Nankai Trough is selected as the grain size distribution of host sand to artificially produce the methane hydrate bearing sand. A shear strength estimation equation for methane hydrate bearing sand from test results is established. A simple constitutive model has been proposed to predict the stress-strain response of methane hydrate bearing sand based on a few well-known relationships. Experimental results indicate that the inclination of stress-dilatancy curve becomes steeper with a rise in methane hydrate saturation. A revised stress-dilatancy equation has been integrated with this simple model to consider the variance in the inclination of stress-dilatancy curve. The mean stress Pcr at critical state when the peak stress ratio reduces to the residual stress ratio increases with the level of methane hydrate saturation. The dilatancy parameter a tends to increase with the methane hydrate saturation. The shear deformability parameter A exhibits a decreasing tendency with the rise in methane hydrate saturation at each confining pressure. This model is capable of reasonably predicting the strength and stiffness enhancement and the dilation behaviour as methane hydrate saturation increases. The volumetric variation from contraction to expansion of MH bearing sand at a lower confining pressure and only pure volumetric contraction a higher confining pressure can be represented by this simple model.

Effects of SP6 Acupuncture Point Stimulation on Labor Pain and Duration of Labor

PubMed Central

Yesilcicek Calik, Kiymet; Komurcu, Nuran

2014-01-01

Background: Acupressure has been used frequently to improve labor, manage labor pain, and shorten delivery time. However, there has been little research-based evidence to support the positive effects of acupressure in the obstetric area and obstetric nursing. Objectives: The aim of this study was to evaluate the effects of SP6 acupressure on labor pain and delivery time in primigravida women in labor. Patients and Methods: The study was conducted at the Trabzon Maternity Hospital in Turkey. Its design was a randomized controlled clinical trial study using a single-blinded method. One hundred (100) primigravida women in labor were randomly assigned to either the SP6 acupressure (n = 50) or control group (n = 50). Acupressure was practiced 35 times in total on the SP6 point of both legs in the SP6 acupressure group; 15 times (during contraction) when cervical dilation was 2-3 cm, 10 times when cervical dilation was 5-6 cm and 10 times at 9-10 cm dilation, while the women in the control group received standard care. Labor pain was measured five times using a structured questionnaire of a subjective labor pain scale (visual analogue scale-VAS) when dilation was 2-3 cm (VAS 2), 5-6 cm (VAS 3) and 8-9 cm (VAS 4) before and after acupressure was applied to the SP6 point (VAS 1), and finally at the early postpartum period (VAS 5). The duration of labor in both groups was measured with a partograph and the length of delivery time was calculated in two stages: from 3 cm cervical dilation to full cervical dilation, and from full cervical dilation to delivery. Results: There were significant differences between the groups in subjective labor pain scores (except VAS 4) (P < 0.001). The duration of the Phase one (3 cm dilatation to full dilatation) and Phase two (full dilatation to birth) in the acupressure group was shorter than the control group (Phase one, 225 min and 320 min, respectively; Phase two, 15 min and 20 min, respectively; both P < 0.001). Conclusions: It was determined that SP6 acupressure was effective in decreasing pain and duration of labor. PMID:25558386

Effects of Patient-Controlled Epidural Analgesia on Uterine Electromyography During Spontaneous Onset of Labor in Term Nulliparous Women.

PubMed

Ye, Yuanjuan; Song, Xingrong; Liu, Lei; Shi, Shao-Qing; Garfield, Robert E; Zhang, Guozheng; Liu, Huishu

2015-11-01

To investigate the effect of patient-controlled epidural analgesia (PCEA) on uterine electromyography (EMG) activity in term pregnant women during labor. Nulliparous pregnant women in spontaneous term labor (N = 30) were enrolled (PCEA group, n = 20 and control group, n = 10). Five time periods (30 minutes each) were defined for noninvasive abdominal recordings and analysis of uterine EMG activity, that is, period I: before PCEA treatment with 2-cm cervical dilation; periods II to IV: each period successively at 30, 60, and 120 minutes after PCEA; and period V: second stage of labor with cervix at 10 cm dilation. Control patients without PCEA were monitored during the same times. The number of bursts/30 min, power density spectrum peak frequency, mean amplitude, and duration of uterine EMG bursts were measured to assess uterine EMG activity. Maternal, fetal, and labor characteristics were also recorded. Data were analyzed by analysis of variance followed by other tests. Electromyography parameters are significantly lower (P < .001) after PCEA (periods II to IV) compared to controls but similar between groups by period V (P > .05). Also, patients with PCEA have a slower rate of cervical dilation (P < .003, period IV only) and longer labor in both stage 1 and stage 2 (P < .05). All patients have similar (P > .05) positive labor outcomes. Patient-controlled epidural analgesia initially suppresses uterine EMG and slows cervical dilation thereby prolonging labor. However, the EMG activity recovers with labor progress with no effects on delivery outcomes. © The Author(s) 2015.

Cervical Dilatation Curves of Spontaneous Deliveries in Pregnant Japanese Females

PubMed Central

Inde, Yusuke; Nakai, Akihito; Sekiguchi, Atsuko; Hayashi, Masako; Takeshita, Toshiyuki

2018-01-01

Background: Although cervical dilatation curves are crucial for appropriate management of labor progression, abnormal labor progression and obstetric interventions were included in previous and widely-used cervical dilatation curves. We aimed to describe the cervical dilatation curves of normal labor progression in pregnant Japanese females without abnormal labor progression and obstetric interventions. Methods: We completed retrospective obstetric record reviews on 3172 pregnant Japanese females (parity = 0, n = 1047; parity = 1, n = 1083; parity ≥ 2, n = 1042), aged 20 to 39 years old at delivery, with pregravid body mass indices of less than 30. All patients underwent spontaneous deliveries with term, singleton, cephalic and live newborns of appropriate-for-gestational age birthweight, without adverse neonatal outcomes. We characterized labor progression patterns by examining the relationship between elapsed times from the full dilatation and cervical dilatation stages, and labor durations by examining the distribution of time intervals from one cervical dilatation stage, to the next, and ultimately to the full dilatation. Results: Fastest cervical changes occurred at 6 cm (primiparas) and 5 cm (multiparas) of dilatation. The 95%tile of labor progression took over 3 hours to progress from 6 cm to 7 cm (primiparas), and over 2 hours to progress from 5 cm to 6 cm (multiparas). The 5%tile of traverse time to the full dilatation, during the active phase, was less than 1 hour (primiparas) and 0.5 hours (multiparas). At the end of the active phase, no deceleration phase was observed. Conclusions: Active labor may not start until 5 cm of dilatation. At the beginning of the active phase, cervical dilatation was slower than previously described. These results may reduce opportunities for obstetric interventions during labor progression. PMID:29725244

Dilation or biodegradable stent placement for recurrent benign esophageal strictures: a randomized controlled trial.

PubMed

Walter, Daisy; van den Berg, Maarten W; Hirdes, Meike M; Vleggaar, Frank P; Repici, Alessandro; Deprez, Pierre H; Viedma, Bartolomé L; Lovat, Laurence B; Weusten, Bas L; Bisschops, Raf; Haidry, Rehan; Ferrara, Elisa; Sanborn, Keith J; O'Leary, Erin E; van Hooft, Jeanin E; Siersema, Peter D

2018-06-08

 Dilation is the standard of care for recurrent benign esophageal strictures (BES). Biodegradable stents may prolong the effect of dilation and reduce recurrences. Efficacy and safety of dilation and biodegradable stent placement early in the treatment algorithm of recurrent BES were compared.  This multicenter, randomized study enrolled patients with BES treated with previous dilations to ≥ 16 mm. The primary end point was number of repeat endoscopic dilations for recurrent stricture within 3 and 6 months. Secondary outcomes through 12 months included safety, time to first dilation for recurrent stricture, dysphagia, and level of activity.  At 3 months, the biodegradable stent group (n = 32) underwent significantly fewer endoscopic dilations for recurrent stricture compared with the dilation group (n = 34; P  < 0.001). By 6 months, the groups were similar. The number of patients experiencing adverse events was similar between the groups. Two patients in the biodegradable stent group died after developing tracheoesophageal fistulas at 95 and 96 days post-placement; no deaths were attributed to the stent. Median time to first dilation of recurrent stricture for the biodegradable stent group was significantly longer (106 vs. 41.5 days; P  = 0.003). Dysphagia scores improved for both groups. Patients in the biodegradable stent group had a significantly higher level of activity through 12 months ( P  < 0.001).  Biodegradable stent placement is associated with temporary reduction in number of repeat dilations and prolonged time to recurrent dysphagia compared with dilation. Additional studies are needed to better define the exact role of biodegradable stent placement to treat recurrent BES. © Georg Thieme Verlag KG Stuttgart · New York.

A comparison among four tract dilation methods of percutaneous nephrolithotomy: a systematic review and meta-analysis.

PubMed

Dehong, Cao; Liangren, Liu; Huawei, Liu; Qiang, Wei

2013-11-01

The purpose of this study was to evaluate the efficacy and safety of the Amplatz dilation (AD), metal telescopic dilation (MTD), balloon dilation (BD), and one-shot dilation (OSD) methods for tract dilation during percutaneous nephrolithotomy (PCNL). Relevant eligible studies were identified using three electronic databases (Medline, EMBASE, and Cochrane CENTRAL). Database acquisition and quality evaluation were independently performed by two reviewers. Efficacy (stone-free rate, surgical duration, and tract dilatation fluoroscopy time) and safety (transfusion rate and hemoglobin decrease) were evaluated using Review Manager 5.2. Four randomized controlled trials and eight clinical controlled trials involving 6,820 patients met the inclusion criteria. The pooled result from a meta-analysis showed statistically significant differences in tract dilatation fluoroscopy time and hemoglobin decrease between the OSD and MTD groups, which showed comparable stone-free and transfusion rates. Significant differences in transfusion rate were found between the BD and MTD groups. Among patients without previous open renal surgery, those who underwent BD exhibited a lower blood transfusion rate and a shorter surgical duration compared with those who underwent AD. The OSD technique is safer and more efficient than the MTD technique for tract dilation during PCNL, particularly in patients with previous open renal surgery, resulting in a shorter tract dilatation fluoroscopy time and a lesser decrease in hemoglobin. The efficacy and safety of BD are better than AD in patients without previous open renal surgery. The OSD technique should be considered for most patients who undergo PCNL therapy.

Esophageal dilation with metal olives under fiberoptic endoscopic control: a new technic.

PubMed

Mangla, J C; Kothari, T

1980-03-01

Three patients with marked strictures (less than 20 Fr.) of the esophagus are described. It was very difficult to institute any simple program of dilation because mercury-filled Maloney bougies will buckle and rigid endoscopy with dilation carries a great risk of perforation. Using the conventional methods such as Eder-Puestow dilation results in significant waste of time, money and fluoroscopic help. A new technic is described whereby a successful dilation was carried out under direct visual control by endoscopic dilation of the esophagus with Eder-Puestow dilators. Since all these patients require esophagoscopy, the dilation procedure can be done in the same sitting.

Eye tracking and pupillometry are indicators of dissociable latent decision processes.

PubMed

Cavanagh, James F; Wiecki, Thomas V; Kochar, Angad; Frank, Michael J

2014-08-01

Can you predict what people are going to do just by watching them? This is certainly difficult: it would require a clear mapping between observable indicators and unobservable cognitive states. In this report, we demonstrate how this is possible by monitoring eye gaze and pupil dilation, which predict dissociable biases during decision making. We quantified decision making using the drift diffusion model (DDM), which provides an algorithmic account of how evidence accumulation and response caution contribute to decisions through separate latent parameters of drift rate and decision threshold, respectively. We used a hierarchical Bayesian estimation approach to assess the single trial influence of observable physiological signals on these latent DDM parameters. Increased eye gaze dwell time specifically predicted an increased drift rate toward the fixated option, irrespective of the value of the option. In contrast, greater pupil dilation specifically predicted an increase in decision threshold during difficult decisions. These findings suggest that eye tracking and pupillometry reflect the operations of dissociated latent decision processes. PsycINFO Database Record (c) 2014 APA, all rights reserved.

C-reactive protein and high mobility group box 1 in dogs with gastric dilatation and volvulus.

PubMed

Uhrikova, Ivana; Rauserova-Lexmaulova, Leona; Rehakova, Kristina; Scheer, Peter; Doubek, Jaroslav

2015-01-01

To (1) measure C-reactive protein (CRP) and high mobility group box 1 (HMGB1) and (2) evaluate their prognostic value and relationship to severity of systemic inflammatory response syndrome, routine hematological and acid-base parameters in dogs with gastric dilatation volvulus (GDV). Prospective observational study from September 2010 to June 2012. Veterinary teaching hospital. Forty-one client-owned dogs with GDV. None. Blood was collected before surgery (baseline), postsurgery, 6-10 hours postsurgery, and 18-22 hours postsurgery. CRP and HMGB1 were measured in all samples, and routine hematological, biochemical, and acid-base analyses were performed. Only baseline and postsurgery samples were used from nonsurvivors (n = 10). CRP increased significantly from postsurgery sampling to 18-22 hours postsurgery, while HMGB1 did not change over time. There was a significant difference in HMGB1 between survivors and nonsurvivors over time. Both proteins correlated with systemic inflammatory response syndrome severity, total leukocyte, segmented neutrophils, and band counts. HMGB1 correlated also with acid-base parameters (pH, bicarbonate, base excess). HMGB1 and CRP behaved differently in regards to their kinetic patterns, with HMGB1 appearing to better reflect the severity of tissue injury in dogs with GDV than CRP. © Veterinary Emergency and Critical Care Society 2015.

Test of Special Relativity Using a Fiber Network of Optical Clocks.

PubMed

Delva, P; Lodewyck, J; Bilicki, S; Bookjans, E; Vallet, G; Le Targat, R; Pottie, P-E; Guerlin, C; Meynadier, F; Le Poncin-Lafitte, C; Lopez, O; Amy-Klein, A; Lee, W-K; Quintin, N; Lisdat, C; Al-Masoudi, A; Dörscher, S; Grebing, C; Grosche, G; Kuhl, A; Raupach, S; Sterr, U; Hill, I R; Hobson, R; Bowden, W; Kronjäger, J; Marra, G; Rolland, A; Baynes, F N; Margolis, H S; Gill, P

2017-06-02

Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching for a daily variation of the frequency difference between four strontium optical lattice clocks in different locations throughout Europe connected by such links, we improve upon previous tests of time dilation predicted by special relativity. We obtain a constraint on the Robertson-Mansouri-Sexl parameter |α|≲1.1×10^{-8}, quantifying a violation of time dilation, thus improving by a factor of around 2 the best known constraint obtained with Ives-Stilwell type experiments, and by 2 orders of magnitude the best constraint obtained by comparing atomic clocks. This work is the first of a new generation of tests of fundamental physics using optical clocks and fiber links. As clocks improve, and as fiber links are routinely operated, we expect that the tests initiated in this Letter will improve by orders of magnitude in the near future.

The effect of pneumatic dilation in management of postfundoplication dysphagia.

PubMed

Sunjaya, D; Podboy, A; Blackmon, S H; Katzka, D; Halland, M

2017-06-01

Fundoplication surgery is a commonly performed procedure for gastro-esophageal reflux disease or hiatal hernia repair. Up to 10% of patients develop persistent postoperative dysphagia after surgery. Data on the effectiveness of pneumatic dilation for treatment are limited. The aim of this study was to evaluate clinical outcomes and identify clinical factors associated with successful response to pneumatic dilation among patients with persistent postfundoplication dysphagia (PPFD). We retrospectively evaluated patients who had undergone pneumatic dilation for PPFD between 1999 and 2016. Patients with dysphagia or achalasia prior to fundoplication were excluded. Demographic information, surgical history, severity of dysphagia, and clinical outcomes were collected. Data pertaining to esophagram, manometry, endoscopy, and pneumatic dilation were also collected. We identified 38 patients (82% female, 95% Caucasian, and median age 59 years) with PPFD who completed pneumatic dilation. The median postfundoplication dysphagia score was 2. Eleven patients had abnormal peristalsis on manometry. Seventeen patients reported response (seven complete) with an average decrease of 1 in their dysphagia score. Fifteen patients underwent reoperation due to PPFD. Hiatal hernia repair was the only factor that predicts a higher response rate to pneumatic dilation. Only one patient in our study developed complication (pneumoperitoneum) from pneumatic dilation. We found that pneumatic dilation to be a safe treatment option for PPFD with moderate efficacy. Patients who developed PPFD after a hiatal hernia repair may gain the greatest benefit after pneumatic dilation. We were not able to identify additional clinical, radiological, endoscopic, or manometric parameters that were predictive of response. © 2017 John Wiley & Sons Ltd.

Exercise-induced cardiac remodeling in non-elite endurance athletes: Comparison of 2-tiered and 4-tiered classification of left ventricular hypertrophy

PubMed Central

De Marchi, Stefano; Seiler, Christian; Brugger, Nicolas; Eser, Prisca

2018-01-01

Background Long-term endurance sport practice leads to eccentric left ventricular hypertrophy (LVH). We aimed to compare the new 4-tiered classification (4TC) for LVH with the established 2-tiered classification (2TC) in a cohort of normotensive non-elite endurance athletes. Methods Male participants of a 10-mile race were recruited and included when blood pressure (BP) was normal (<140/90 mmHg). Phenotypic characterization of LVH was based on relative wall thickness (2TC), and on LV concentricity2/3 (LV mass/end-diastolic volume [LVM/EDV]2/3) plus LVEDV index (4TC). Parameters of LV geometry, BP, cumulative training hours, and race time were compared between 2TC and 4TC by analysis of variance, and post-hoc analysis. Results Of 198 athletes recruited, 174 were included. Mean age was 41.6±7.5 years. Forty-two (24%) athletes had LVH. Allocation in the 2TC was: 32 (76%) eccentric LVH and 10 (24%) concentric LVH. Using the 4TC 12 were reclassified to concentric LVH, and 2 to eccentric LVH, resulting in 22 (52%) eccentric LVH (7 non-dilated, 15 dilated), and 20 (48%) concentric LVH (all non-dilated). Based on the 2TC, markers of endurance training did not differ between eccentric and concentric LVH. Based on the 4TC, athletes with eccentric LVH had more cumulative training hours and faster race times, with highest values thereof in athletes with eccentric dilated LVH. Conclusions In our cohort of normotensive endurance athletes, the new 4TC demonstrated a superior discrimination of exercise-induced LVH patterns, compared to the established 2TC, most likely because it takes three-dimensional information of the ventricular geometry into account. PMID:29462182

Pupil dilation during recognition memory: Isolating unexpected recognition from judgment uncertainty.

PubMed

Mill, Ravi D; O'Connor, Akira R; Dobbins, Ian G

2016-09-01

Optimally discriminating familiar from novel stimuli demands a decision-making process informed by prior expectations. Here we demonstrate that pupillary dilation (PD) responses during recognition memory decisions are modulated by expectations, and more specifically, that pupil dilation increases for unexpected compared to expected recognition. Furthermore, multi-level modeling demonstrated that the time course of the dilation during each individual trial contains separable early and late dilation components, with the early amplitude capturing unexpected recognition, and the later trailing slope reflecting general judgment uncertainty or effort. This is the first demonstration that the early dilation response during recognition is dependent upon observer expectations and that separate recognition expectation and judgment uncertainty components are present in the dilation time course of every trial. The findings provide novel insights into adaptive memory-linked orienting mechanisms as well as the general cognitive underpinnings of the pupillary index of autonomic nervous system activity. Copyright © 2016 Elsevier B.V. All rights reserved.

Contribution of Different Anatomical and Physiologic Factors to Iris Contour and Anterior Chamber Angle Changes During Pupil Dilation: Theoretical Analysis

PubMed Central

Jouzdani, Sara; Amini, Rouzbeh; Barocas, Victor H.

2013-01-01

Purpose. To investigate the contribution of three anatomical and physiologic factors (dilator thickness, dynamic pupillary block, and iris compressibility) to changes in iris configuration and anterior chamber angle during pupil dilation. Methods. A mathematical model of the anterior segment based on the average values of ocular dimensions was developed to simulate pupil dilation. To change the pupil diameter from 3.0 to 5.4 mm in 10 seconds, active dilator contraction was applied by imposing stress in the dilator region. Three sets of parameters were varied in the simulations: (1) a thin (4 μm, 1% of full thickness) versus a thick dilator (covering the full thickness iris) to quantify the effects of dilator anatomy, (2) in the presence (+PB) versus absence of pupillary block (−PB) to quantify the effect of dynamic motion of aqueous humor from the posterior to the anterior chamber, and (3) a compressible versus an incompressible iris to quantify the effects of iris volume change. Changes in the apparent iris–lens contact and angle open distance (AOD500) were calculated for each case. Results. The thin case predicted a significant increase (average 700%) in iris curvature compared with the thick case (average 70%), showing that the anatomy of dilator plays an important role in iris deformation during dilation. In the presence of pupillary block (+PB), AOD500 decreased 25% and 36% for the compressible and incompressible iris, respectively. Conclusions. Iris bowing during dilation was driven primarily by posterior location of the dilator muscle and by dynamic pupillary block, but the effect of pupillary block was not as large as that of the dilator anatomy according to the quantified values of AOD500. Incompressibility of the iris, in contrast, had a relatively small effect on iris curvature but a large effect on AOD500; thus, we conclude that all three effects are important. PMID:23482467

One shot tract dilation for percutaneous nephrolithotomy: is it safe and effective in preschool children?

PubMed

Hosseini, Seyed Reza; Mohseni, Mohammad Ghasem; Alizadeh, Farshid

2014-01-01

To evaluate the safety and feasibility of percutaneous tract dilation by the one-stage method in preschool children. Between April 2009 and February 2013, all preschool (<6 years) children who were candidates for percutaneous nephrolithotomy were enrolled in this prospective study. Patients were randomly assigned to dilation by serial metallic dilators (group I, 31 patients) or dilation by one-stage Amplatz according to Frattini et al. [J Endourol 2001;15:919-923] (group II, 31 patients). The primary endpoint of interest was fluoroscopy time. Secondary endpoints included tract creation and dilation time, success rate and complications. Stone-free status was defined as residuals ≤3 mm. Age, stone size, operation success and operation time were not significantly different between the studied groups. The most common stone composition was calcium oxalate in both groups. The mean ± standard deviation of access and fluoroscopy times in groups I and II were 7.3 ± 1.2 min vs. 5.9 ± 1.5 min (p > 0.05) and 70.0 ± 8.9 s vs. 22.0 ± 5.6 s (p < 0.001), respectively. Postoperative complications included one case of postoperative fever lasting less than 48 h in group I. Percutaneous tract dilation by the one-stage method is safe and effective. Also, it is associated with considerably less radiation exposure in preschool children. © 2014 S. Karger AG, Basel.

Balloon dilation of the esophago-gastric junction affects lower and upper esophageal sphincter function in achalasia.

PubMed

Wauters, L; Van Oudenhove, L; Selleslagh, M; Vanuytsel, T; Boeckxstaens, G; Tack, J; Omari, T; Rommel, N

2014-01-01

Pneumatic dilation of the lower esophageal sphincter (LES) in achalasia has an unappreciated effect on upper esophageal sphincter (UES) function. We studied UES pressure patterns at baseline and alterations in UES parameters resulting from therapy. High-resolution manometry (HRM) tracings from 50 achalasia patients, seen at a tertiary center between January 2009 and July 2011, were reviewed. Manometric parameters studied were (i) LES: resting pressure (restP), 4-second integrated relaxation pressure (IRP4); (ii) UES: resting pressure (restP), minimal relaxation pressure (MRP), peak pressure (PP), relaxation interval (RI), intrabolus pressure (IBP), and deglutitive sphincter resistance (DSR). Mixed models analyses with LES and UES parameters as dependent variables and treatment stage as within-subject independent variable of interest were used. Correlations between treatment-induced changes in LES, UES, and esophageal body (EB) parameters were performed. Pre- and posttreatment HRM tracings were available from 50 patients (mean age 52.7 ± 18.6 years, 29 men). Upper esophageal sphincter parameters MRP (17.9 ± 1.2 vs 15.2 ± 0.9 mmHg; p = 0.02) and IBP (31.5 ± 1.5 vs 27.4 ± 1.2 mmHg; p = 0.009) were significantly reduced after initial balloon dilation and this effect was significant in type II achalasia (p = 0.002 and p = 0.0006). Peak pressure, RI, and DSR were not. The therapeutic effect on LES IRP4 correlated significantly with the change in UES MRP, statistically mediated by the change in EB deglutitive pressure (p = 0.004 and p = 0.0002). We present the first HRM study demonstrating that pneumatic dilation of the LES affects intraesophageal and UES pressures in patients with achalasia. © 2013 John Wiley & Sons Ltd.

Endothelial microparticles and vascular parameters in subjects with and without arterial hypertension and coronary artery disease.

PubMed

Sansone, Roberto; Baaken, Maximilian; Horn, Patrick; Schuler, Dominik; Westenfeld, Ralf; Amabile, Nicolas; Kelm, Malte; Heiss, Christian

2018-08-01

Endothelial microparticles (EMPs) are markers of endothelial injury and activation. The role of EMPs in arterial hypertension is not well understood and EMPs are increased both in arterial hypertension and coronary artery disease (CAD). The data presented here show EMPs as defined by CD31 + /41 - , CD62e + , and CD144 + surface markers and vascular hemodynamic parameters including office and central blood pressure, heart rate, aortic augmentation index, pulse wave velocity, flow-mediated dilation, nitroglycerin-mediated dilation, brachial artery diameter, hyperemic wall shear stress, and laser Doppler perfusion of the cutaneous microcirculation of normotensives and hypertensives with and without CAD.

Factors associated with the improvement of vocal fold movement: an analysis of LEMG and laryngeal CT parameters.

PubMed

Mengsteab, Paulos Y; Kwon, Jeong-Yi; Han, Tai Ryoon; Kwon, Tack Kyun; Kim, Deok-Ho; Kim, Sang Jun

2015-02-01

The aim of this study is to elucidate the relationship of laryngeal electromyography (LEMG) and computed tomographic (CT) parameters to improve the prognosis of recurrent laryngeal nerve injury. 22 patients clinically suspected of having recurrent laryngeal nerve injury were examined with LEMG and CT studies. Bilateral thyroarytenoid (TA) muscles were examined and findings were interpreted by a single blind technique. Laryngeal CT image analysis of the ventricle dilation symmetry determined TA muscle atrophy. Finally, a follow-up laryngoscopic examination determined improvement of vocal fold movement. Ventricle dilation symmetry and the dichotomized TA muscle atrophy parameter significantly relate to the improvement of vocal fold movement (χ(2)=4.029, P=0.039, and χ(2)=3.912, P=0.048, respectively). When the severity of vocal fold impairment was classified as severe TA muscle atrophy or none/discrete MUAP recruitment, it was found to significantly relate with the improvement of vocal fold movement (χ(2)=6.712, P=.010). From this study, image analysis of the ventricle dilation symmetry to determine the severity of TA muscle atrophy shows promise for the improved prognosis of vocal fold immobility. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative study of balloon and metal olive dilators for endoscopic management of benign anastomotic rectal strictures: clinical and cost-effectiveness outcomes.

PubMed

Xinopoulos, Dimitrios; Kypreos, Dimitrios; Bassioukas, Stefanos P; Korkolis, Dimitrios; Mavridis, Konstantinos; Scorilas, Andreas; Dimitroulopoulos, Dimitrios; Loukou, Argyro; Paraskevas, Emmanouel

2011-03-01

Postoperative anastomotic strictures frequently complicate colorectal resection. Currently, various endoscopic techniques are being employed in their management, but the establishment of an optimal therapeutic strategy is still pending. The purpose of our study is to compare through-the-scope (TTS) balloon dilators versus Eder-Puestow metal olive dilators in the treatment of postoperative benign rectal strictures, considering the clinical outcome and cost-effectiveness of each method. A total of 39 patients with benign anastomotic rectal stenosis were retrospectively studied. In group A, 15 patients underwent dilation with Eder-Puestow metal olives, while in group B 19 patients were treated by means of TTS balloon dilators. The technical and clinical success of dilation, complications, number of repeated sessions required, disease-free time intervals, and the overall cost of each procedure were evaluated. Dilations were technically successful in all patients. No major complications occurred in either group. The number of dilations needed, rate of stricture recurrence, and duration of stenosis-free time intervals were not statistically significantly different between the two groups. Both methods proved more effective in older patients, given the greater number of dilations required in younger patients of both groups and higher frequency of stricture relapse in younger balloon-dilated patients (median 64.00 years) compared with older ones (median 75.00 years) (p = 0.001). An indisputable advantage of the Eder-Puestow technique, compared with TTS balloon dilators, is the low cost of equipment (median 22.30 compared with 680 , respectively; p < 0.001). Endoscopic dilation of postoperative benign rectal strictures is equally effective and safe, especially in older patients, when performed by Eder-Puestow bougies or TTS balloon dilators. However, metal olivary tips seem to surpass balloon dilators when considering the obvious economical benefits of the first method.

Wavelet based analysis of multi-electrode EEG-signals in epilepsy

NASA Astrophysics Data System (ADS)

Hein, Daniel A.; Tetzlaff, Ronald

2005-06-01

For many epilepsy patients seizures cannot sufficiently be controlled by an antiepileptic pharmacatherapy. Furthermore, only in small number of cases a surgical treatment may be possible. The aim of this work is to contribute to the realization of an implantable seizure warning device. By using recordings of electroenzephalographical(EEG) signals obtained from the department of epileptology of the University of Bonn we studied a recently proposed algorithm for the detection of parameter changes in nonlinear systems. Firstly, after calculating the crosscorrelation function between the signals of two electrodes near the epileptic focus, a wavelet-analysis follows using a sliding window with the so called Mexican-Hat wavelet. Then the Shannon-Entropy of the wavelet-transformed data has been determined providing the information content on a time scale in subject to the dilation of the wavelet-transformation. It shows distinct changes at the seizure onset for all dilations and for all patients.

Interfacial tensiometry and dilational surface visco-elasticity of biological liquids in medicine.

PubMed

Fainerman, V B; Trukhin, D V; Zinkovych, Igor I; Miller, R

2018-05-01

Dynamic surface tensions and dilational visco-elasticity are easy accessible parameters of liquids. For human body liquids, such as urine, blood serum, amniotic fluid, gastric juice, saliva and others, these parameters are very characteristic for the health status of people. In case of a disease the composition of certain liquids specifically changes and the measured characteristics of dynamic surface tension of the dilational surface elasticity and viscosity reflect these changes in a clear way. Thus, this kind of physico-chemical measurements represent sensitive tools for evaluating the severity of a disease and can serve as control tool for the efficiency of applied therapies. The overview summarises the results of a successful work over about 25years on this subject and gives specific insight into a number of diseases for which the diagnostics as well as the therapy control have been significantly improved by the application of physico-chemical experimental techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

[A simple model for describing pressure-volume curves in free balloon dilatation with reference the dynamics of inflation hydraulic aspects].

PubMed

Bloss, P; Werner, C

2000-06-01

We propose a simple model to describe pressure-time and pressure-volume curves for the free balloon (balloon in air) of balloon catheters, taking into account the dynamics of the inflation device. On the basis of our investigations of the flow rate-dependence of characteristic parameters of the pressure-time curves, the appropriateness of this simple model is demonstrated using a representative example. Basic considerations lead to the following assumptions: (1) the flow within the shaft of the catheter is laminar, and (ii) the volume decrease of the liquid used for inflation due to pressurization can be neglected if the liquid is carefully degassed prior to inflation, and if the total volume of the liquid in the system is less than 2 ml. Taking into account the dynamics of the inflation device used for pumping the liquid into the proximal end of the shaft during inflation, the inflation process can be subdivided into the following three phases: initial phase, filling phase and dilatation phase. For these three phases, the transformation of the time into the volume coordinates is given. On the basis of our model, the following parameters of the balloon catheter can be determined from a measured pressure-time curve: (1) the resistance to flow of the liquid through the shaft of the catheter and the resulting pressure drop across the shaft, (2) the residual volume and residual pressure of the balloon, and (3) the volume compliance of the balloon catheter with and without the inflation device.

Gene therapy ameliorates cardiovascular disease in dogs with mucopolysaccharidosis VII.

PubMed

Sleeper, M M; Fornasari, B; Ellinwood, N M; Weil, M A; Melniczek, J; O'Malley, T M; Sammarco, C D; Xu, L; Ponder, K P; Haskins, M E

2004-08-17

Mucopolysaccharidosis VII (MPS VII) is a lysosomal storage disease caused by deficient beta-glucuronidase (GUSB) activity resulting in defective catabolism of glycosaminoglycans (GAGs). Cardiac disease is a major cause of death in MPS VII because of accumulation of GAGs in cardiovascular cells. Manifestations include cardiomyopathy, mitral and aortic valve thickening, and aortic root dilation and may cause death in the early months of life or may be compatible with a fairly normal lifespan. We previously reported that neonatal administration of a retroviral vector (RV) resulted in transduction of hepatocytes, which secreted GUSB into the blood and could be taken up by cells throughout the body. The goal of this study was to evaluate the effect on cardiac disease. Six MPS VII dogs were treated intravenously with an RV-expressing canine GUSB. Echocardiographic parameters, cardiovascular lesions, and biochemical parameters of these dogs were compared with those of normal and untreated MPS VII dogs. RV-treated dogs were markedly improved compared with untreated MPS VII dogs. Most RV-treated MPS VII dogs had mild or moderate mitral regurgitation at 4 to 5 months after birth, which improved or disappeared when evaluated at 9 to 11 and at 24 months. Similarly, mitral valve thickening present early in some animals disappeared over time, whereas aortic dilation and aortic valve thickening were absent at all times. Both myocardium and aorta had significant levels of GUSB and reduction in GAGs.

One-shot versus gradual dilation technique for tract creation in percutaneous nephrolithotomy: a systematic review and meta-analysis.

PubMed

Li, Yutao; Yang, Lu; Xu, Peng; Shen, Pengfei; Qian, Shengqiang; Wei, Wuran; Wang, Jia

2013-10-01

The aim of this study is to evaluate the efficacy and safety of one-shot versus gradual dilation technique for tract creation in percutaneous nephrolithotomy (PCNL). A systematic research of Pubmed, Embase and the Cochrane Library was performed to identify all relevant studies. The quality of the included trials was assessed and the data were extracted independently by two reviewers. The Cochrane Collaboration's Review Manager (RevMan) 5.0.2 software was used for statistical analysis. Four randomized controlled trials were included in analysis involving 346 patients in total. Of these patients 174 were in the one-shot group and 172 in the gradual group. Our meta-analysis showed that there were no significant differences in successful dilation rate [risk ratio (RR): 0.96; 95 % confidence interval (CI): 0.92-1.00, p = 0.05], transfusion rate (RR: 0.62; 95 % CI: 0.20-1.96; p = 0.42), and hemoglobin decrease [mean difference (MD): -0.34; 95 % CI: from -0.67 to -0.00; p = 0.05] between one-shot dilation and gradual dilation. One-shot dilation had significant shorter access time (MD: -1.03; 95 % CI: from -1.57 to -0.49; p = 0.0002) and X-ray exposure time (MD: -42.71; 95 % CI: from -45.05 to -40.37; p < 0.00001) than gradual dilation. Our results show that One-shot dilation is an effective and safe procedure for tract creation in PCNL, with shorter access time and X-ray exposure time and without increased complications. As only four studies with small study populations were available, more high-quality larger trials with longer follow-up are recommended.

Radionuclide esophageal transit: an evaluation of therapy in achalasia

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKinney, M.K.; Brady, C.E.; Weiland, F.L.

1983-09-01

We measured quantitative esophageal transit, expressed as percentage of esophageal retention, before and after pneumatic dilatation in two patients with achalasia. In the sitting position they ingested a 500 ml liquid meal containing 500 muCi technetium Tc 99m sulfur colloid. Radioactivity counts of the entire esophagus were plotted at five-minute intervals for 30 minutes. In five normal control subjects the esophagus essentially cleared in less than one minute. Both patients with achalasia had definite retention 30 minutes before dilatation and had quantitative improvement after dilatation. Radionuclide scintigraphic esophageal transit probably correlates better than other parameters with the physiologic degree ofmore » obstruction in achalasia.« less

Post-Launch Analysis of Swift's Gamma-Ray Burst Detection Sensitivity

NASA Technical Reports Server (NTRS)

Band, David L.

2005-01-01

The dependence of Swift#s detection sensitivity on a burst#s temporal and spectral properties shapes the detected burst population. Using s implified models of the detector hardware and the burst trigger syste m I find that Swift is more sensitive to long, soft bursts than CGRO# s BATSE, a reference mission because of its large burst database. Thu s Swift has increased sensitivity in the parameter space region into which time dilation and spectral redshifting shift high redshift burs ts.

Osteopontin--a fibrosis-related marker--in dilated cardiomyopathy in patients with Emery-Dreifuss muscular dystrophy.

PubMed

Niebroj-Dobosz, Irena; Madej-Pilarczyk, Agnieszka; Marchel, Michał; Sokołowska, Beata; Hausmanowa-Petrusewicz, Irena

2011-12-01

As osteopontin (OPN) may be assumed to have diagnostic/prognostic value in heart diseases, it is worth assessing whether it is also involved in the pathogenesis and can be applied in the diagnosis of the dilated cardiomyopathy (DCM) in Emery-Dreifuss muscular dystrophy (EDMD). Serum levels of osteopontin were quantified by means of sandwich immunoassay in 25 EDMD patients (10 laminopathies AD-EDMD and 15 emerinopathies--X-EDMD), eight carriers of X-EDMD, nine disease controls (patients with dystrophinopathy) and 20 age-matched healthy controls. The levels of circulating OPN were elevated in all AD-EDMD and X-linked EDMD patients, as well as in X-EDMD carriers and patients suffering progressive muscular dystrophy. There was no correlation between the osteopontin level and different cardiac parameters, including left-ventricular end-diastolic diameter, left atrial diameter, the left ventricular ejection fraction and the CK-MB level. There was a slight negative correlation with the ages of the patients. The presented results indicate that assessments of circulating OPN levels may help to identify EDMD patients at risk of dilated cardiomyopathy and might be therefore included among the set of biomarkers referred to with a view to appropriate early cardiologic diagnosis and therapy being commenced with in time.

Timing of left heart base descent in dogs with dilated cardiomyopathy and normal dogs.

PubMed

Simpson, Kerry E; Devine, Bryan C; Woolley, Richard; Corcoran, Brendan M; French, Anne T

2008-01-01

The identification and assessment of myocardial failure in canine idiopathic dilated cardiomyopathy (DCM) is achieved using a variety of two-dimensional and Doppler echocardiographic techniques. More recently, the availability of tissue Doppler imaging (TDI) has raised the potential for development of new ways of more accurately identifying a disease phenotype. Nevertheless, TDI has not been universally adapted to veterinary clinical cardiology primarily because of the lack of information on its utility in diagnosis. We assessed the application of timing of left heart base descent using TDI in the identification of differences between DCM and normal dogs. The times from the onset of the QRS complex on a simultaneously recorded electrocardiograph to the onset (Q--S'), peak (Q--peak S'), and end (Q--end S') of the systolic velocity peak were measured in the interventricular septum (IVS) and the left ventricular free wall. The duration of S' was also calculated. The Q--S' (FW), Q--end S' (FW), and duration S' (FW) were correlated with ejection fraction in the diseased group (P < 0.05). In addition, Q--S', Q--peak S', Q--end S', and the peak S' velocity were prolonged in the diseased dogs at both the free wall and in the IVS (P < 0.01). The duration of S' was unaffected by disease status. These findings provide insight into the electromechanical uncoupling that occurs in canine DCM and identifies new TDI parameters that can be added to the range of Doppler and echocardiographic parameters used for detecting myocardial failure in the dog.

Prediction of fracture healing under axial loading, shear loading and bending is possible using distortional and dilatational strains as determining mechanical stimuli.

PubMed

Steiner, Malte; Claes, Lutz; Ignatius, Anita; Niemeyer, Frank; Simon, Ulrich; Wehner, Tim

2013-09-06

Numerical models of secondary fracture healing are based on mechanoregulatory algorithms that use distortional strain alone or in combination with either dilatational strain or fluid velocity as determining stimuli for tissue differentiation and development. Comparison of these algorithms has previously suggested that healing processes under torsional rotational loading can only be properly simulated by considering fluid velocity and deviatoric strain as the regulatory stimuli. We hypothesize that sufficient calibration on uncertain input parameters will enhance our existing model, which uses distortional and dilatational strains as determining stimuli, to properly simulate fracture healing under various loading conditions including also torsional rotation. Therefore, we minimized the difference between numerically simulated and experimentally measured courses of interfragmentary movements of two axial compressive cases and two shear load cases (torsional and translational) by varying several input parameter values within their predefined bounds. The calibrated model was then qualitatively evaluated on the ability to predict physiological changes of spatial and temporal tissue distributions, based on respective in vivo data. Finally, we corroborated the model on five additional axial compressive and one asymmetrical bending load case. We conclude that our model, using distortional and dilatational strains as determining stimuli, is able to simulate fracture-healing processes not only under axial compression and torsional rotation but also under translational shear and asymmetrical bending loading conditions.

Influence of mechanically-induced dilatation on the shape memory behavior of amorphous polymers at large deformation

NASA Astrophysics Data System (ADS)

Hanzon, Drew W.; Lu, Haibao; Yakacki, Christopher M.; Yu, Kai

2018-01-01

In this study, we explore the influence of mechanically-induced dilatation on the thermomechanical and shape memory behavior of amorphous shape memory polymers (SMPs) at large deformation. The uniaxial tension, glass transition, stress relaxation and free recovery behaviors are examined with different strain levels (up to 340% engineering strain). A multi-branched constitutive model that incorporates dilatational effects on the polymer relaxation time is established and applied to assist in discussions and understand the nonlinear viscoelastic behaviors of SMPs. It is shown that the volumetric dilatation results in an SMP network with lower viscosity, faster relaxation, and lower Tg. The influence of the dilatational effect on the thermomechanical behaviors is significant when the polymers are subject to large deformation or in a high viscosity state. The dilation also increases the free recovery rate of SMP at a given recovery temperature. Even though the tested SMPs are far beyond their linear viscoelastic region when a large programming strain is applied, the free recovery behavior still follows the time-temperature superposition (TTSP) if the dilatational effect is considered during the transformation of time scales; however, if the programming strain is different, TTSP fails in predicting the recovery behavior of SMPs because the network has different entropy state and driving force during shape recovery. Since most soft active polymers are subject to large deformation in practice, this study provides a theoretical basis to better understand their nonlinear viscoelastic behaviors, and optimize their performance in engineering applications.

Balloon dilatation in esophageal strictures in epidermolysis bullosa and the role of anesthesia.

PubMed

Gollu, Gulnur; Ergun, Ergun; Ates, Ufuk; Can, Ozlem S; Dindar, Huseyin

2017-02-01

Esophageal involvement, which causes stricture, is a complication in epidermolysis bullosa. This causes dysphagia and malnutrition and leads to deterioration of skin lesions in these patients. The charts of 11 patients with epidermolysis bullosa and esophageal stricture who were included into dilatation program between 2003 and 2015 were retrospectively reviewed. Seven of the patients were female and four were male. The median age was 14 (2-32) years. The mean body weight of patients was 27.8 (9-51) kg. The location and number of strictured parts of the esophagus were previously evaluated with upper gastrointestinal contrast study and after that flexible endoscopy was used for dilatation. Eight patients had middle esophageal, three patients had proximal esophageal and one of them had both proximal and middle esophageal strictures. The strictures were dilated 56 times in total (mean 5 times). One patient underwent gastrostomy and was medically followed-up after a perforation occurrence during the dilatation procedure. In a 32-year-old female patient, colon interposition was performed after four dilatations since optimal nutritional and developmental status could not be achieved. The dilatation program of nine patients is still in progress. Seven of them can easily swallow solid food but two of them have some difficulties in swallowing between dilatations. One patient rejected the program and quitted, while one patient refused colon interposition and died because of complications related to amyloidosis during the dilatation program. After resolution of the swallowing problem, skin lesions were observed to heal quickly. Epidermolysis bullosa is a rare cause of dysphagia. Esophageal balloon dilatation with flexible endoscopy is a safe and efficient method in patients with this condition. © 2016 International Society for Diseases of the Esophagus.

Improved test of time dilation in special relativity.

PubMed

Saathoff, G; Karpuk, S; Eisenbarth, U; Huber, G; Krohn, S; Muñoz Horta, R; Reinhardt, S; Schwalm, D; Wolf, A; Gwinner, G

2003-11-07

An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2).

Impact of sickle cell anaemia on cardiac chamber size in the paediatric population.

PubMed

Adjagba, Philippe M; Habib, Gaston; Robitaille, Nancy; Pastore, Yves; Raboisson, Marie-Josée; Curnier, Daniel; Dahdah, Nagib

2017-07-01

Purpose Sickle cell disease is known to cause various degrees of vasculopathy, including impact on heart function. The aims of this single-centre, retrospective study were to assess cardiac chamber size and function and the relationship with haematological indices such as haemoglobin, aspartate aminotransferase, reticulocytosis and bilirubin, lactate dehydrogenase in sickle cell disease. Right ventricle and left ventricle diastolic diameters, left ventricle mass estimate, left ventricle shortening fraction, myocardial performance index, and an index of myocardial relaxation (E/E') were calculated and correlated with haematological parameters. A total of 110 patients (65% haemoglobin SS, 29% haemoglobin SC) were studied at a mean age of 12.14±5.26 years. Right ventricle dilatation and left ventricle dilatation were present in 61.5 and 42.9%, respectively. Left ventricle mass was abnormal in 21.9%; all patients had normal myocardial performance index, 31.4% had abnormal E/E', and left ventricle shortening fraction was low in 38.1%. Cardiac dilatation was best correlated with haemoglobin, aspartate aminotransferase, reticulocytosis and bilirubin. Best subset regression analysis yielded significant additional prediction for right ventricle or left ventricle dilatation with haemoglobin, bilirubin, and lactate dehydrogenase. Abnormal E/E' was solely predictable with haemoglobin level. Hydroxyurea-treated patients had improved diastolic function. Right ventricle dilatation was more prevalent than left ventricle dilatation. The long-term consequences of right ventricular dilatation, clinical consequences, and association with pulmonary vasculopathy need to be further determined.

A novel percutaneous nephrolithotomy (PCNL) set: The 'Economical One-shot PCNL Set' (Ecoset).

PubMed

Penbegul, Necmettin; Dede, Onur; Daggulli, Mansur; Hatipoglu, Namik Kemal; Bozkurt, Yasar

2017-09-01

To suggest a novel disposable percutaneous nephrolithotomy (PCNL) set that we named the ' Ec onomical O ne-shot PCNL Set ' (Ecoset), which consists of a single 30-F dilator, 30-F sheath, and 8-F polyurethane dilator, as use of a 'one-shot' dilatation technique during PCNL is becoming widespread. The medical records of 42 patients with kidney stones who had undergone 'one-shot' PCNL from February 2014 to June 2016 were retrospectively reviewed and analysed. Demographic data, as well as the stone size, radiation exposure time, operation time, hospitalisation duration, rate of treatment success and complications, were recorded. The mean (SD, range) age of the patients was 44.43 (16.54, 11-72) years. The mean (SD) stone size was 35.12 (17.53) mm. The mean (SD) operation time was 54.58 (22.24) min. The mean (SD) fluoroscopic screening time was limited to 154.72 (117.48) s. Treatment success was achieved in 32 (76%) patients. The mean (SD) hospital stay was 3.09 (0.75) days. None of the patients had any major complications. Bleeding requiring blood transfusion was required in three patients. The cost of a disposable dilatation set for a single PCNL operation with a balloon set, a standard Amplatz set, or an Ecoset is ∼$137, $120, or $27 (American dollars), respectively. The one-shot dilatation technique using the Ecoset for PCNL can be feasibly, safely, and effectively performed in almost every adult patient. The Amplatz dilator set and balloon dilator set have the disadvantage of relatively high cost, whereas the Ecoset is the cheapest 'disposable set' that can be used during PCNL surgery.

A single center 26-year experience with treatment of esophageal achalasia: is there an optimal method?

PubMed

Pastor, Aimee C; Mills, Jessica; Marcon, Margaret A; Himidan, Sharifa; Kim, Peter C W

2009-07-01

Treatment modalities for achalasia are evolving and remain controversial. Herein, we report the relative efficacy and outcomes after dilatation or myotomy in children with achalasia. A retrospective analysis of all children treated for achalasia at a tertiary center from 1981 to 2007 was performed (n = 40). Demographics, presenting symptoms, perioperative parameters, and outcomes were analyzed using t tests and chi(2) statistics. Thirty patients were initially treated by esophageal dilatation (ED), whereas 10 were treated by laparoscopic or open Heller myotomy (HM). Both groups were similar with respect to age (10.6 vs 12.4 years; P = .19). There were 18 males and 12 females in the ED group, compared to 5 males and 5 females in the HM group (P = .72). Mean duration of symptoms before diagnosis, including dysphagia, vomiting, food sticking, chest pain, and weight loss, was 15.9 months for ED and 10.7 months for HM (P = .41). Mean time from diagnosis to initial intervention was 76 days in ED vs 86 days in HM (P = .78). Subsequent interventions by myotomy or both dilatation and myotomy were required in 9 (30%) of 30 patients in the ED group and 2 (20%) of 10 patients in the HM group (P = .70). A clear transition from open to laparoscopic approach occurred between 1995 and 2001. Mean operating times were comparable (186.3 vs 156.0 minutes; P = .48). Of 14 laparoscopic myotomies, 11 (79%) had fundoplication, and 2 (18%) of the 11 were converted to open procedure. Intraoperative mucosal perforation rates were similar between open and laparoscopic groups (17% vs 18%). At follow-up, 32% of ED patients vs 43% HM had complete symptom relief (mean follow-up duration, 75.2 months; SD, 196.5). Both dilatation and myotomy are effective immediate treatment of achalasia. A clear transition to and preference for laparoscopic approach has occurred in the treatment of achalasia in children.

CMBE v05-Implementation of a toy-model for chaos analysis of relativistic nuclear collisions at the present BNL energies

NASA Astrophysics Data System (ADS)

Grossu, I. V.; Felea, D.; Jipa, Al.; Besliu, C.; Stan, E.; Ristea, O.; Ristea, C.; Calin, M.; Esanu, T.; Bordeianu, C.; Tuturas, N.

2014-11-01

In this paper we present a new version of Chaos Many-Body Engine (CMBE) Grossu et al. (2014) [1]. Inspired by the Mean Free Path concept, we implemented a new parameter, namely the ;Mean Free Time;, which is defined as the mean time between one particle's creation and its stimulated decay. This new parameter should be understood as an effect of the nuclear environment and, as opposed to the particle lifetime, it has the advantage of not being affected by the relativistic dilation. In [2] we presented a toy-model for chaos analysis of relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration). In this work, we extended our model to 200 A GeV (the maximum BNL energy).

New labor management guidelines and changes in cesarean delivery patterns.

PubMed

Rosenbloom, Joshua I; Stout, Molly J; Tuuli, Methodius G; Woolfolk, Candice L; López, Julia D; Macones, George A; Cahill, Alison G

2017-12-01

In 2010 the Consortium on Safe Labor published labor curves. It was proposed that the rate of cesarean delivery could be lowered by avoiding the diagnosis of arrest of dilation before 6 cm. However, there is little information on the uptake of the guidelines and on changes in cesarean delivery rates that may have occurred. The objective of the study was to test the following hypotheses: (1) among patients laboring at term, rates of arrest of dilation disorders have decreased, leading to a decrease in the rate of cesarean delivery; (2) in the second stage, pushing duration prior to diagnosis of arrest of descent has increased, also leading to a reduction in the rate of cesarean delivery for this indication. As a secondary aim, we investigated changes in maternal and neonatal morbidity. This was a secondary analysis of a prospective cohort study of all patients presenting at ≥37 weeks' gestation from 2010 through 2014 with a nonanomalous vertex singleton and no prior history of cesarean delivery. Rates of cesarean delivery, arrest of dilation, and changes in rates of maternal and neonatal morbidity were calculated in crude and adjusted models. Cervical dilation at diagnosis of the arrest of dilation, time spent at the maximal dilation prior to diagnosis of arrest of dilation, and time in the second stage prior to the diagnosis of arrest of descent were compared over the study period. There were 7845 eligible patients. The cesarean delivery rate in 2010 was 15.8% and, in 2014, 17.7% (P trend = .51). In patients undergoing cesarean delivery for the arrest of dilation, the median cervical dilation at the time of cesarean delivery was at 5.5 cm in 2010 and 6.0 cm in 2014 (P trend = .94). In these patients, there was an increase in the time spent at last dilation: 3.8 hours in 2010 to 5.2 hours in 2014 (P trend = .02). There was no change in the frequency of patients diagnosed with the arrest of dilation at <6 cm: 51.4% in 2010 and 48.6% in 2014 (P trend = .56). However, in these patients, the median time spent at the last cervical dilation was 4.0 hours in 2010 and 6.7 hours in 2014 (P trend = .046). There were 206 cesarean deliveries for the arrest of descent. The median pushing time in these patients increased in multiparous patients from 1.1 hours in 2010 to 3.4 hours in 2014 (P trend = .009); in nulliparous patients these times were 2.7 hours in 2010 and 3.8 hours in 2014 (P trend = .09). There was a significant trend toward increasing adverse neonatal and maternal outcomes (P < .001 for each). The adjusted odds ratio for adverse maternal outcome for 2014 compared with 2010 was 1.66 (95% confidence interval, 1.27-2.17); however, considering only transfusion, hemorrhage, or infection, there was no difference (P trend = .96). The adjusted odds ratio of adverse neonatal outcome in 2014 compared with 2010 was 1.80 (95% confidence interval, 1.36-2.36). Despite significant changes in labor management that have occurred over the initial years since publication of the new labor curves and associated guidelines, the primary cesarean delivery rate was not reduced and there has been an increase in maternal and neonatal morbidity in our institution. A randomized controlled trial is needed. Copyright © 2017 Elsevier Inc. All rights reserved.

2D Simulations of Earthquake Cycles at a Subduction Zone Based on a Rate and State Friction Law -Effects of Pore Fluid Pressure Changes-

NASA Astrophysics Data System (ADS)

Mitsui, Y.; Hirahara, K.

2006-12-01

There have been a lot of studies that simulate large earthquakes occurring quasi-periodically at a subduction zone, based on the laboratory-derived rate-and-state friction law [eg. Kato and Hirasawa (1997), Hirose and Hirahara (2002)]. All of them assume that pore fluid pressure in the fault zone is constant. However, in the fault zone, pore fluid pressure changes suddenly, due to coseismic pore dilatation [Marone (1990)] and thermal pressurization [Mase and Smith (1987)]. If pore fluid pressure drops and effective normal stress rises, fault slip is decelerated. Inversely, if pore fluid pressure rises and effective normal stress drops, fault slip is accelerated. The effect of pore fluid may cause slow slip events and low-frequency tremor [Kodaira et al. (2004), Shelly et al. (2006)]. For a simple spring model, how pore dilatation affects slip instability was investigated [Segall and Rice (1995), Sleep (1995)]. When the rate of the slip becomes high, pore dilatation occurs and pore pressure drops, and the rate of the slip is restrained. Then the inflow of pore fluid recovers the pore pressure. We execute 2D earthquake cycle simulations at a subduction zone, taking into account such changes of pore fluid pressure following Segall and Rice (1995), in addition to the numerical scheme in Kato and Hirasawa (1997). We do not adopt hydrostatic pore pressure but excess pore pressure for initial condition, because upflow of dehydrated water seems to exist at a subduction zone. In our model, pore fluid is confined to the fault damage zone and flows along the plate interface. The smaller the flow rate is, the later pore pressure recovers. Since effective normal stress keeps larger, the fault slip is decelerated and stress drop becomes smaller. Therefore the smaller flow rate along the fault zone leads to the shorter earthquake recurrence time. Thus, not only the frictional parameters and the subduction rate but also the fault zone permeability affects the recurrence time of earthquake cycle. Further, the existence of heterogeneity in the permeability along the plate interface can bring about other slip behaviors, such as slow slip events. Our simulations indicate that, in addition to the frictional parameters, the permeability within the fault damage zone is one of essential parameters, which controls the whole earthquake cycle.

The analysis and modelling of dilatational terms in compressible turbulence

NASA Technical Reports Server (NTRS)

Sarkar, S.; Erlebacher, G.; Hussaini, M. Y.; Kreiss, H. O.

1991-01-01

It is shown that the dilatational terms that need to be modeled in compressible turbulence include not only the pressure-dilatation term but also another term - the compressible dissipation. The nature of these dilatational terms in homogeneous turbulence is explored by asymptotic analysis of the compressible Navier-Stokes equations. A non-dimensional parameter which characterizes some compressible effects in moderate Mach number, homogeneous turbulence is identified. Direct numerical simulations (DNS) of isotropic, compressible turbulence are performed, and their results are found to be in agreement with the theoretical analysis. A model for the compressible dissipation is proposed; the model is based on the asymptotic analysis and the direct numerical simulations. This model is calibrated with reference to the DNS results regarding the influence of compressibility on the decay rate of isotropic turbulence. An application of the proposed model to the compressible mixing layer has shown that the model is able to predict the dramatically reduced growth rate of the compressible mixing layer.

The analysis and modeling of dilatational terms in compressible turbulence

NASA Technical Reports Server (NTRS)

Sarkar, S.; Erlebacher, G.; Hussaini, M. Y.; Kreiss, H. O.

1989-01-01

It is shown that the dilatational terms that need to be modeled in compressible turbulence include not only the pressure-dilatation term but also another term - the compressible dissipation. The nature of these dilatational terms in homogeneous turbulence is explored by asymptotic analysis of the compressible Navier-Stokes equations. A non-dimensional parameter which characterizes some compressible effects in moderate Mach number, homogeneous turbulence is identified. Direct numerical simulations (DNS) of isotropic, compressible turbulence are performed, and their results are found to be in agreement with the theoretical analysis. A model for the compressible dissipation is proposed; the model is based on the asymptotic analysis and the direct numerical simulations. This model is calibrated with reference to the DNS results regarding the influence of compressibility on the decay rate of isotropic turbulence. An application of the proposed model to the compressible mixing layer has shown that the model is able to predict the dramatically reduced growth rate of the compressible mixing layer.

Laser driven short-term thermal angioplasty: enhancement of drug delivery performance by heating with tension

NASA Astrophysics Data System (ADS)

Suganuma, Kao; Homma, Rie; Shimazaki, Natsumi; Ogawa, Emiyu; Arai, Tsunenori

2017-02-01

To enhance drug delivery performance of drug eluting balloon (DEB) against re-stenosis, we have proposed a heating drug delivery during balloon dilatation using our laser driven short-term thermal angioplasty which may realize to suppress surrounding thermal injury. We studied an influence of vessel dilatation parameters on the heating drug delivery. These parameters were classified into two different forces, that is, circumferential tension and inter-luminal pressure. We think these parameters were not able to determine only by balloon pressure. The circumferential tension with 0-30 mN/mm2 was added to a porcine carotid artery using an automatic stage. Various temperature solutions with 37, and 70°C of hydrophobic fluorescent Rhodamine B with 3 μg/ml in concentration were dropped on pig carotid wall. We measured a defined drug delivery amount as well as delivery depth by a microscopic fluorescence measurement on the cross section of the solution delivered vessel. In the case of 37°C, we found the intima surface drug amount with 7 mN/mm2 was increased as 10-20 times as other tension cases. On the other hand, at 70°C, we found the optimum tension with 30 mN/mm2. We found the drug delivery enhancement might be related to the change of super microscopic surface structure of the vessel. We predict that the collagen thermal denaturation of the vessel wall might play important role to the drug delivery.

Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) as a Predictor of Future Surgical Intervention for Infants With High-grade Prenatal Hydronephrosis.

PubMed

Rickard, Mandy; Lorenzo, Armando J; Braga, Luis H

2017-03-01

To explore the potential value of an objective assessment, renal parenchyma to hydronephrosis area ratio (PHAR), as an early predictor of surgery. Initial sagittal renal ultrasound (US) images of patients prospectively entered into a prenatal hydronephrosis database from January 2008 to January 2016 with baseline Society for Fetal Urology (SFU) grades III and IV prenatal hydronephrosis, without vesicoureteral reflux, were evaluated using the National Institutes of Health-sponsored image processing software. PHAR, anteroposterior diameter, SFU grade, and urinary tract dilation risk categories were contrasted with nuclear scan data (differential renal function and drainage time [t 1/2 ]) and analyzed for predictive value in determining the decision to proceed with surgery by drawing receiver operating characteristic curves. Out of 196 infants (162 male; 138 left sided hydronephrosis), 58 (30%) underwent surgery to address obstruction. Surgical patients compared with those managed conservatively had longer t 1/2 (60 vs 18 min; P < .01) and lower differential renal function (46 vs 50%; P = .01). Of the initial US parameters, PHAR (area under the curve = 0.816; P < .001) had a better predictive performance than anteroposterior diameter, SFU grade, or urinary tract dilation classification. PHAR values correlated with subsequent parameters obtained on nuclear scan. PHAR is a promising parameter that can be estimated on presentation US to help predict future need for surgery in newborns with high-grade hydronephrosis. Copyright © 2016 Elsevier Inc. All rights reserved.

High-resolution manometry findings in patients with achalasia and massive dilated megaesophagus.

PubMed

Menezes, M A; Andolfi, C; Herbella, F A M; Patti, M G

2017-05-01

Achalasia may present in a non-advanced or an advanced (end stage) stage based on the degree of esophageal dilatation. Manometric parameters and esophageal caliber may be prognostic for the outcome of treatment. The correlation between manometry and disease stage has not been yet fully studied. This study aims to describe high-resolution manometry findings in patients with achalasia and massive dilated megaesophagus. Eighteen patients (mean age 61 years, 55% females) with achalasia and massive dilated megaesophagus, as defined by a maximum esophageal dilatation >10 cm at the barium esophagram, were studied. Achalasia was considered secondary to Chagas' disease in 14 (78%) of the patients and idiopathic in the remaining. All patients underwent high-resolution manometry. Upper esophageal sphincter was hypotonic and had impaired relaxation in the majority of patients. Aperistalsis was seen in all patients with an equal distribution of Chicago type I and type II. No type III was noticed. Lower esophageal sphincter did not have a characteristic manometric pattern. In 50% of the cases, the manometry catheter was not able to reach the stomach. Our results did not show a manometric pattern in patients with achalasia and massive dilated esophagus. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Treatment of oropharyngeal dysphagia secondary to idiopathic cricopharyngeal bar: Surgical cricopharyngeal muscle myotomy versus dilation.

PubMed

Marston, Alexander P; Maldonado, Francisco J; Ravi, Karthik; Kasperbauer, Jan L; Ekbom, Dale C

To compare swallowing outcomes following cricopharyngeal (CP) dilation versus surgical myotomy in patients with dysphagia secondary to idiopathic CP bar. All patients had an idiopathic CP bar without a history of Zenker's diverticulum, head and neck cancer, or systemic neurologic disease treated between 2000 and 2013. The Functional Outcome Swallowing Scale (FOSS) was utilized to assess dysphagia symptoms. Twenty-three patients underwent 46 dilations and 20 patients had a myotomy. Nineteen of 23 (83%) patients in the dilation group and all patients in the myotomy group reported improved swallow function. The median difference in pre- versus post-intervention FOSS scores was not statistically significant (p=0.07) between the dilation and myotomy groups with mean reductions of 1.3 and 1.8, respectively. Seventeen of 23 (74%) dilation patients had persistent or recurrent dysphagia with 13 (57%) requiring repeat dilation and 4 (17%) undergoing CP myotomy. The median time to first reintervention in the dilation group was 13.6months. Nineteen of 20 (95%) surgical myotomy patients did not experience recurrent dysphagia. Both endoscopic CP dilation and myotomy led to similar initial improvement in swallow function for patients with primary idiopathic CP bar; however, dilation is more likely to provide temporary benefit. Copyright © 2016 Elsevier Inc. All rights reserved.

Dilatation of aortic grafts over time: what to expect and when to be concerned.

PubMed

Schroeder, Torben V; Eldrup, Nikolaj; Just, Sven; Hansen, Marc; Nyhuus, Bo; Sillesen, Henrik

2009-06-01

Dilatation of aortic prosthetic grafts is commonly reported, but most reports are anecdotal, with little objective data in the literature. We performed a prospective trial of 303 patients who underwent prosthetic graft repair for aortic aneurysm or occlusive disease, randomizing patients between insertion of a woven polyester or expanded polytetrafluoroethylene (ePTFE) graft. Patients were followed with computed tomography and ultrasonography for up to 5 years in order to assess the frequency and magnitude of postoperative dilatation. Graft dilatation was documented in patients with polyester grafts at 12 months. Thereafter and up to 60 months, polyester grafts did not dilate further. After 5 years, polyester prostheses had dilated by 25% and ePTFE by 12.5%, as determined by computed tomography imaging. These observations suggest that dilatation of prosthetic grafts is more frequent with knitted polyester grafts compared with ePTFE. Dilatation occurs within the first year after implantation and can be, in part, explained by a discrepancy between the initial nominal graft diameter and its diameter after clamp release, probably due to an in vivo adaptation of the textile structure. Interestingly, graft dilatation did not appear to be associated with an increased frequency of graft-related complications.

Intermittent dysphagia for solids associated with a multiringed esophagus: clinical features and response to dilatation.

PubMed

Lee, Greta Shao-Chu; Craig, Philip Ian; Freiman, John Saul; de Carle, David; Cook, Ian James

2007-01-01

The entity of the multiringed esophagus, generally presenting in adults as intermittent dysphagia for solids, is relatively uncommon and its pathogenesis is unknown. The goal of this study was to describe the demographic, clinical, and endoscopic features of patients presenting with this condition, their response to esophageal dilatation, and the relationship of multiple esophageal rings to eosinophilic esophagitis. Between 1989 and June 2004, 32 patients at this adult hospital fulfilled the following inclusion criteria: (1) intermittent dysphagia for solids, (2) multiple esophageal rings at endoscopy, and (3) esophageal dilatation(s) performed. Response to esophageal dilatation was measured by need for subsequent dilatations. Seventy-five percent of the patients were male. Median age at onset of dysphagia was 21 years and at presentation 36.5 years. All had multiple rings in the proximal or midesophagus on endoscopy and had undergone a total of 73 esophageal dilatations with no esophageal perforations. Median maximal dilator size was 15 mm; however, 16% developed significant esophageal mucosal tears even with 11-mm dilators. Sixty-six percent required repeat dilatation, with the median time interval before recurrence being 8 months. Eosinophilic esophagitis (mucosal eosinophil count > 20/HPF) was present in 50% of this cohort. From this study we conclude that a multiringed esophagus causing intermittent dysphagia occurs predominantly in young males, responds well to dilatation, but repeated dilatations are often necessary. Dilatation can lead to extensive mucosal tears and should be performed with caution. Eosinophilic esophagitis is commonly but not invariably associated with this entity. Frequent relapse of dysphagia highlights the need for effective pharmacotherapy.

Endoscopic electrocautery dilation of benign anastomotic colonic strictures: a single-center experience.

PubMed

Bravi, Ivana; Ravizza, Davide; Fiori, Giancarla; Tamayo, Darina; Trovato, Cristina; De Roberto, Giuseppe; Genco, Chiara; Crosta, Cristiano

2016-01-01

Benign anastomotic colonic stenosis sometimes occur after surgery and usually require surgical or endoscopic dilation. Endoscopic dilation of anastomotic colonic strictures by using balloon or bougie-type dilators has been demonstrated to be safe and effective in multiple uncontrolled series. However, few data are available on safety and efficacy of endoscopic electrocautery dilation. The aim of our study was to retrospectively investigate safety and efficacy of endoscopic electrocautery dilation of postsurgical benign anastomotic colonic strictures. Sixty patients (37 women; median age 63.6 years, range 22.6-81.7) with benign anastomotic colonic or rectal strictures treated with endoscopic electrocautery dilation between June 2001 and February 2013 were included in the study. Anastomotic stricture was defined as a narrowed anastomosis through which a standard colonoscope could not be passed. Only annular anastomotic strictures were considered suitable for electrocautery dilation which consisted of radial incisions performed with a precut sphincterotome. Treatment was considered successful if the colonic anastomosis could be passed by a standard colonoscope immediately after dilation. Recurrence was defined as anastomotic stricture reappearance during follow-up. The time interval between colorectal surgery and the first endoscopic evaluation or symptoms development was 7.3 months (1.3-60.7). Electrocautery dilation was successful in all the patients. There were no procedure-related complications. Median follow-up was 35.5 months (2.0-144.0). Anastomotic stricture recurrence was observed in three patients who were successfully treated with electrocautery dilation and Savary dilation. Endoscopic electrocautery dilation is a safe and effective treatment for annular benign anastomotic postsurgical colonic strictures.

Incidence of gastric dilatation-volvulus following a splenectomy in 238 dogs.

PubMed

Maki, Lynn C; Males, Kristina N; Byrnes, Madeline J; El-Saad, Anthony A; Coronado, George S

2017-12-01

There is contradicting information in the veterinary literature regarding canine splenectomy and the increased risk for subsequent gastric dilatation-volvulus. The main purpose of this study was to determine the rate of occurrence of gastric dilatation-volvulus following splenectomy in medium to large breed dogs compared with a control group undergoing other abdominal procedures. Follow-up was performed by reviewing the medical records and conducting phone interviews. Weight, gender, and presence of a hemoabdomen at the time of surgery were not significantly associated with occurrence of gastric dilatation-volvulus, while increasing age was. Ten of 238 (4%) dogs in the splenectomy group and 3/209 (1.4%) dogs in the control group subsequently developed gastric dilatation-volvulus, which was not significantly different ( P = 0.08). While the findings approach significance and support a need for future investigation, the current recommendation for gastropexy at time of splenic removal should be made on a case by case basis and while considering previously documented risk factors.

Percutaneous nephrolithotomy with one-shot dilation method: Is it safe in patients who had open surgery before?

PubMed

Süelözgen, Tufan; Isoglu, Cemal Selcuk; Turk, Hakan; Yoldas, Mehmet; Karabicak, Mustafa; Ergani, Batuhan; Boyacioglu, Hayal; Ilbey, Yusuf Ozlem; Zorlu, Ferruh

2016-01-01

This study aimed to evaluate whether one-shot dilatation technique is as safe in patients with a history of open-stone surgery as it is in patients without previous open-stone surgery. Between January 2007 and February 2015, 82 patients who underwent percutaneous nephrolithotomy (PNL) surgery with one-shot dilation technique who previously had open-stone surgery were retrospectively reviewed and evaluated (Group 1). Another 82 patients were selected randomly among patients who had PNL with one-shot dilation technique, but with no history of open renal surgery (Group 2). Age, gender, type of kidney stone, duration of surgery, radiation exposure time, and whether or not there was any bleeding requiring perioperative and postoperative transfusion were noted for each patient. The stone-free rates, operation and fluoroscopy time, and peroperative and postoperative complication rates were similar in both groups (p>0.05). Our experience indicated that PNL with one-shot dilation technique is a reliable method in patients with a history of open-stone surgery.

Topical Mitomycin C application in the treatment of refractory benign esophageal strictures in adults and comprehensive literature review.

PubMed

Bartel, Michael J; Seeger, Kristina; Jeffers, Kayin; Clayton, Donnesha; Wallace, Michael B; Raimondo, Massimo; Woodward, Timothy A

2016-09-01

Recurrent complex esophageal strictures remain difficult to manage. To determine the efficacy of topical Mitomycin C application for recurrent benign esophageal strictures. All patients who underwent balloon dilation followed by topical Mitomycin C application for recurrent benign esophageal strictures were included. Primary outcome was number of dilations and change of dysphagia score. Nine patients with anastomotic (3), radiation-induced (3), caustic (2), and combined anastomotic and radiation-induced (1) strictures were included. Strictures had a mean length of 13.75mm, diameter of 8.0mm, and were dilated 10.7 times over a median of 8 months (1.5 dilations per month). Following Mitomycin C application, the need for further dilation decreased to 0.39 dilations per month over a median of 10 months; however, dysphagia scores improved not significantly from 3.2 to 2.6 (mean). In this pilot study, topical Mitomycin C in conjunction with dilation decreased the frequency of esophageal dilations for recurrent benign esophageal strictures. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Combined antegrade and retrograde esophageal dilation for head and neck cancer-related complete esophageal stenosis.

PubMed

Goguen, Laura A; Norris, Charles M; Jaklitsch, Michael T; Sullivan, Christopher A; Posner, Marshall R; Haddad, Robert I; Tishler, Roy B; Burke, Elaine; Annino, Donald J

2010-02-01

Assess the safety and efficacy of combined antegrade and retrograde esophageal dilation (CARD) for complete esophageal stenosis following head and neck cancer (HNC) treatment. Review HNC dysphagia management. Retrospective review of all patients undergoing CARD following HNC treatment between May 2001 and September 2008. Forty-five patients were identified for review. Parameters assessed included: ability to obtain intraoperative esophageal patency, complications, number of dilations required, diet, and gastric tube (GT) status. Factors associated with dilation failure were analyzed. Intraoperative esophageal patency was obtained in 91% of patients. Median number of all dilations per patient was three. Median number of CARDs per patient was one. Resumption of oral intake occurred in 36/45 (80%). Diet results included: regular or soft diet 32/45 (71%), GT removal 27/45 (60%), and GT dependence with nothing by mouth 9/45 (20%). Laryngeal and pharyngeal stenosis, radionecrosis, tracheotomy dependence, and elongated stenosis were associated with dilation failure. Complications occurred in 18/63 (29%) CARD procedures: eight pneumomediastinum, seven GT site problems, two esophageal perforations, and one pharyngeal infection. All complications resolved spontaneously or with minimal interventions. CARD was safe and effective. Intraoperative patency was achieved in 91% of patients. Eighty percent resumed oral intake. The majority of patients had their GTs removed and resumed a soft or regular diet. Dilation failure was associated with laryngeal, pharyngeal, and excessively long esophageal stenosis, often resulting from radionecrosis. Complications were minor. CARD should be considered before relegating patients with complete esophageal stenosis to chronic GT dependence or subjecting them to laryngopharyngo esophagectomy.

The Universality of Time Dilation and Space Contraction.

ERIC Educational Resources Information Center

Daly, Lisa N.; Horton, George K.

1994-01-01

Describes the extended general physics course taught at Rutgers University. The course presents to students at the high school algebra level the topic of analyzing a particular thought experiment that yields the time dilation formula and subsequently space contraction, velocity addition, and other 20th-century physics concepts. (MVL)

Observations of fault zone heterogeneity effects on stress alteration and slip nucleation during a fault reactivation experiment in the Mont Terri rock laboratory, Switzerland

NASA Astrophysics Data System (ADS)

Nussbaum, C.; Guglielmi, Y.

2016-12-01

The FS experiment at the Mont Terri underground research laboratory consists of a series of controlled field stimulation tests conducted in a fault zone intersecting a shale formation. The Main Fault is a secondary order reverse fault that formed during the creation of the Jura fold-and-thrust belt, associated to a large décollement. The fault zone is up to 6 m wide, with micron-thick shear zones, calcite veins, scaly clay and clay gouge. We conducted fluid injection tests in 4 packed-off borehole intervals across the Main Fault using mHPP probes that allow to monitor 3D displacement between two points anchored to the borehole walls at the same time as fluid pressure and flow rate. While pressurizing the intervals above injection pressures of 3.9 to 5.3 MPa, there is an irreversible change in the displacements magnitude and orientation associated to the hydraulic opening of natural shear planes oriented N59 to N69 and dipping 39 to 58°. Displacements of 0.01 mm to larger than 0.1 mm were captured, the highest value being observed at the interface between the low permeable fault core and the damage zone. Contrasted fault movements were observed, mainly dilatant in the fault core, highly dilatant-normal slip at the fault core-damage zone interface and low dilatant-strike-slip-reverse in the damage-to-intact zones. First using a slip-tendency approach based on Coulomb reactivation potential of fault planes, we computed a stress tensor orientation for each test. The input parameters are the measured displacement vectors above the hydraulic opening pressure and the detailed fault geometry of each intervals. All measurements from the damage zone can be explained by a stress tensor in strike-slip regime. Fault movements measured at the core-damage zone interface and within the fault core are in agreement with the same stress orientations but changed as normal faulting, explaining the significant dilatant movements. We then conducted dynamic hydromechanical simulations of the Coulomb stress variations on discrete fault planes, considering the injection pressure variations with time in the packed-off sections as the source parameters. Results suggest that the fault architecture and heterogeneity play an important role on the local stress variation at the core-damage zone interface, favouring slip activation below sigma 3.

Sublingual versus vaginal misoprostol for cervical dilatation 1 or 3 h prior to surgical abortion: a double-blinded RCT.

PubMed

Sääv, Ingrid; Kopp Kallner, Helena; Fiala, Christian; Gemzell-Danielsson, Kristina

2015-06-01

Can sublingual administration of misoprostol 1 h prior to vacuum aspiration be more effective than vaginal administration and as effective as either route three 3 h prior to surgery? Sublingually administered misoprostol is superior to vaginally administered misoprostol when given 1 h pre operatively, and it is as effective as after a three 3 h priming interval with either route of administration. Misoprostol reduces complications and morbidity when used for cervical priming prior to surgical dilatation and vacuum aspiration in first trimester pregnancy. Despite the widespread use and extensive studies, the optimal route of administration of misoprostol before surgical abortion remains to be defined. The optimal priming interval after vaginal and sublingual administration of 400 mcg misoprostol has been reported to be 3 h. A longer interval will not improve dilatation but will increase the risk for bleeding and expulsion of the uterine contents before surgical evacuation. The pharmacokinetic properties of misoprostol indicate that sublingual compared with vaginal administration of misoprostol may result in a more rapid cervical priming effect. Women were randomized to four treatment groups and received 400 mcg misoprostol sublingually, or vaginally, 1 or 3 h prior to surgery. The study was a double-blinded RCT with regard to route of misoprostol administration but not the timing interval. The primary outcome was baseline cervical dilatation after misoprostol priming. The study was conducted between June 2007 and March 2014 and 184 women aged 18 years or older were recruited. Women were recruited among nulliparous women undergoing elective surgical first trimester abortion. Exclusion criteria were any contraindication for misoprostol, untreated genital infection, previous history of surgery to the cervix, or abnormal pregnancy. Gestational age was established by endovaginal ultrasound examination. The trial was conducted in a university hospital outpatient clinic. The allocated medication (misoprostol and placebo) was self-administered 1 h or 3 h prior to surgery. All women received 2 tablets of 200 mcg misoprostol and 2 identical looking placebo tablets. Prophylactic pain medication, 100 mg oral diclofenac, was administered at the time of misoprostol. Side effects were recorded immediately before surgery and women were asked which administration route of administration they found most convenient and which they would have preferred. The exact priming time (from misoprostol administration to initiation of dilatation) and signs of bleeding prior to dilatation were recorded. Vacuum aspiration was performed under general anaesthesia according to clinical routine. Dilatation was performed using tapered Pratt-dilatators and the resistance of the cervix was assessed objectively using a tonometer. All surgery was performed by two investigators, experienced in using the tonometer. The cumulative force required to dilate the cervix was calculated by adding the peak force needed for each dilatator up to 9.7 mm. The time needed for surgery including cervical dilatation and vacuum aspiration, was recorded. Intra-operative blood loss was measured and any surgical complications noted. Six women were excluded retrospectively from the analysis. Multivariate analysis of the primary outcome baseline dilatation showed a significant influence on route of administration (P = 0.034, 95% confidence interval (CI) -2.202, -0.086) as well as the interaction variable between route of administration and total priming time (P = 0.042, 95% CI 0.00, 0.016), with the vaginal route becoming more effective with longer priming time. These factors also had a significant influence on the peak force (administration route P = 0.042, 95% CI 0.221, 12.427, interaction P = 0.049, 95% CI -0.089, 0.000) and cumulative force (administration route P = 0.023, 95% CI 3.142, 40.877, interaction P = 0.026, 95% CI -0.293, -0.019) used for dilatation. The total priming time had a significant influence on bleeding before surgery, with more women bleeding the longer the total priming time (P = 0.003, 95% CI 2.203, 49.706). For abdominal pain before surgery there was a significant influence of administration route (P = < 0.001 95% CI 0.028, 0.235) and the interaction variable between administration route and priming time (P = 0.003, 95% CI 2.005, 30.757) with more women in the sublingual group experiencing abdominal pain the longer the priming time. The groups did not differ regarding duration of surgery, amount of bleeding and rate of side effects, such as nausea and shivering. Women in our study preferred vaginal treatment, as they disliked the taste of the misoprostol tablets. Vaginal treatment was also perceived as quicker to administer (P = 0.0001). The cervical tissue has viscoelastic properties, i.e. tissue resistance to mechanical dilatation depends also on the rate at which dilatation is performed. The ideal measurement of dilatation force should therefore also record the rate and time of dilatation. To ensure comparability, only nulliparous women without prior cervical surgery were recruited. In addition, time of dilatation was recorded and did not differ between the groups, and it is therefore assumed that dilatation took place at approximately the same rate. A limitation is that the study was conducted over a long time period because there was only one tonometer, decreasing numbers of surgical abortions and the fact that the main author was on a rotation schedule. In addition, the study was not powered to detect differences in side effects. Priming with misoprostol is recommended prior to surgical abortion. The priming interval of misoprostol may be reduced to 1 h after sublingual administration but not after vaginal administration. The results of the present study will increase choice and flexibility in cervical priming. The Swedish research council (521-2009-2605), Swedish Council for Working Life and Social Research (1404/08), Stockholm County Council and Karolinska Institutet (ALF 2009-2012). All authors declare that they have no conflicts of interest. www.clincaltrials.gov, NCT 01933360. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Prognostic significance of dilated inferior vena cava in advanced decompensated heart failure.

PubMed

Lee, Hsin-Fu; Hsu, Lung-An; Chang, Chi-Jen; Chan, Yi-Hsin; Wang, Chun-Li; Ho, Wan-Jing; Chu, Pao-Hsien

2014-10-01

Dilated inferior vena cava (IVC) is prevalent among patients with heart failure (HF), but whether its presence predicts worsening renal function (WRF) or adverse outcomes is unclear. This cohort study analyzed patients with left ventricular ejection fraction <40 % and repeated hospitalizations (≥2 times) for HF between August 2009 and August 2011. The study endpoints were death and HF re-hospitalization. Among baseline parameters, IVC diameter was the most powerful predictor for the development of WRF (area under the curve = 0.795, cut-off value = 20.5 mm). During the 2-year follow-up, 36 patients (49 %) were re-hospitalized for HF and 14 patients (19 %) died. The event rates were significantly greater in the WRF group than in the non-WRF group (71 vs. 30 %, P < 0.001 for HF re-hospitalization; 29 vs. 10 %, P = 0.03 for death). In Cox regression model, the risk of combined end-points was increased in patients with aging, elevated blood urine nitrogen, IVC >21 mm, and WRF. When adjusted for confounding factors, IVC >21 mm [hazard ratio (HR) 3.73, 95 % confidence interval (CI) 1.66-8.34] and WRF (HR 2.68, 95 % CI 1.07-6.75) were significant predictors for adverse outcomes. In patients with advanced decompensated HF, dilated IVC (>21 mm) predicted the development of WRF and could be a predictor for adverse outcomes.

A randomized trial of vaginal misoprostol for cervical priming before hysteroscopy in postmenopausal women

PubMed Central

Kant, Anita; Divyakumar; Priyambada, Usha

2011-01-01

Objective: To perform hysteroscopy the cervix needs to be dilated and in nullipara and postmenopausal women this is sometimes difficult. Well-known, entry-related complications during hysteroscopy include cervical tear, creation of false tract, bleeding, uterine perforation, scarring, and subsequent anatomical stenosis. Materials and Methods: This study was done to investigate the priming effect of vaginal misoprostol on cervical dilatation in postmenopausal women, before hysteroscopy, to prevent such complications. Two hundred micrograms of misoprostol was inserted into the vagina at least 12 hours before the procedure and the control group did not receive any cervical priming agent. Pre-procedural dilatation, additional dilatation required, and time taken for dilatation was noted in each case. Observations: The study showed a significant difference between the study group (7.7 ± 1.7 mm) and the control group (4.5 ± 1.8 mm) in terms of pre-procedural cervical width and the number of women requiring a dditional dilatation (7 / 25 versus 22 / 25), and hence, the time required for dilatation (4.7 ± 8 seconds versus 20.6 ± 9.3 seconds). Conclusion: The pre-procedural cervical width was significantly more in the study group as compared to that in the control group. We found significant differences between the study and control groups with respect to the number of women who required cervical dilatation. To conclude, this study helps derive a conclusion that vaginal misoprostol as a cervical priming agent in postmenopausal women appears to be safe, effective, and inexpensive, with mild side effects. PMID:21897735

Psychological and Neural Mechanisms of Subjective Time Dilation

PubMed Central

van Wassenhove, Virginie; Wittmann, Marc; Craig, A. D. (Bud); Paulus, Martin P.

2011-01-01

For a given physical duration, certain events can be experienced as subjectively longer in duration than others. Try this for yourself: take a quick glance at the second hand of a clock. Immediately, the tick will pause momentarily and appear to be longer than the subsequent ticks. Yet, they all last exactly 1 s. By and large, a deviant or an unexpected stimulus in a series of similar events (same duration, same features) can elicit a relative overestimation of subjective time (or “time dilation”) but, as is shown here, this is not always the case. We conducted an event-related functional magnetic neuroimaging study on the time dilation effect. Participants were presented with a series of five visual discs, all static and of equal duration (standards) except for the fourth one, a looming or a receding target. The duration of the target was systematically varied and participants judged whether it was shorter or longer than all other standards in the sequence. Subjective time dilation was observed for the looming stimulus but not for the receding one, which was estimated to be of equal duration to the standards. The neural activation for targets (looming and receding) contrasted with the standards revealed an increased activation of the anterior insula and of the anterior cingulate cortex. Contrasting the looming with the receding targets (i.e., capturing the time dilation effect proper) revealed a specific activation of cortical midline structures. The implication of midline structures in the time dilation illusion is here interpreted in the context of self-referential processes. PMID:21559346

The relativistic foundations of synchrotron radiation.

PubMed

Margaritondo, Giorgio; Rafelski, Johann

2017-07-01

Special relativity (SR) determines the properties of synchrotron radiation, but the corresponding mechanisms are frequently misunderstood. Time dilation is often invoked among the causes, whereas its role would violate the principles of SR. Here it is shown that the correct explanation of the synchrotron radiation properties is provided by a combination of the Doppler shift, not dependent on time dilation effects, contrary to a common belief, and of the Lorentz transformation into the particle reference frame of the electromagnetic field of the emission-inducing device, also with no contribution from time dilation. Concluding, the reader is reminded that much, if not all, of our argument has been available since the inception of SR, a research discipline of its own standing.

Outlook with conservative treatment of peptic oesophageal stricture.

PubMed Central

Ogilvie, A L; Ferguson, R; Atkinson, M

1980-01-01

In order to assess the outlook for patients with peptic oesophageal strictures treated by Eder Puestow dilatation at fibreoptic endoscopy, 50 patients were followed up for periods ranging from nine months to four years. Twenty patients (40%) required only a single dilatation, and the remaining 30 (60%) required multiple dilatations. The frequency of dilatation tended to decrease with time. There was one death attributable to the procedure. Two patients developed an adenocarcinoma at the site of the stricture. We conclude that conservative management of peptic oesophageal stricture combining the use of dilatation at fibreoptic endoscopy with medical measures to control gastro-oesophageal reflux offers a relatively safe means of providing symptomatic relief, maintaining nutrition, and allowing the patient an acceptable quality of life. PMID:7364314

The pressure-dilatation correlation in compressible flows

NASA Technical Reports Server (NTRS)

Sarkar, S.

1992-01-01

Simulations of simple compressible flows have been performed to enable the direct estimation of the pressure-dilatation correlation. The generally accepted belief that this correlation may be important in high-speed flows has been verified by the simulations. The pressure-dilatation correlation is theoretically investigated by considering the equation for fluctuating pressure in an arbitrary compressible flow. This leads to the isolation of a component of the pressure-dilatation that exhibits temporal oscillations on a fast time scale. Direct numerical simulations of homogeneous shear turbulence and isotropic turbulence show that this fast component has a negligible contribution to the evolution of turbulent kinetic energy. Then, an analysis for the case of homogeneous turbulence is performed to obtain a formal solution for the nonoscillatory pressure-dilatation. Simplifications lead to a model that algebraically relates the pressure-dilatation to quantities traditionally obtained in incompressible turbulence closures. The model is validated by direct comparison with the simulations.

A Symmetry Approach to Time Dilation.

ERIC Educational Resources Information Center

Dunne, Peter

1995-01-01

Outlines an approach to introduce students to special relativity using a discussion of stopclocks and measurement of the transmission of light pulses to produce a natural derivation of the time dilation factor. Aims at providing a frame of reference from which they can be tempted to explore special relativity at a more sophisticated level. (JRH)

A Simple Derivation of Time Dilation and Length Contraction in Special Relativity

ERIC Educational Resources Information Center

Behroozi, Fred

2014-01-01

Undergraduate physics majors typically begin their study of modern physics with special relativity. It is here that physics students first encounter the counterintuitive concepts of time dilation and length contraction. Unfortunately, the derivations of these results are often cloaked in several layers of analysis that render them rather…

Pore dilation reconsidered

PubMed Central

Bean, Bruce P

2015-01-01

Previous experiments have suggested that many P2X family channels undergo a time-dependent process of pore dilation when activated by ATP. Li et al. now propose a different interpretation of the key experiments. PMID:26505561

Cervical dilation before first-trimester surgical abortion (<14 weeks' gestation).

PubMed

Allen, Rebecca H; Goldberg, Alisa B

2016-04-01

First-trimester surgical abortion is a common, safe procedure with a major complication rate of less than 1%. Cervical dilation before suction abortion is usually accomplished using tapered mechanical dilators. Risk factors for major complications in the first trimester include increasing gestational age and provider inexperience. Cervical priming before first-trimester surgical abortion has been studied using osmotic dilators and pharmacologic agents, most commonly misoprostol. Extensive data demonstrate that a variety of agents are safe and effective at causing preoperative cervical softening and dilation; however, given the small absolute risk of complications, the benefit of routine use of misoprostol or osmotic dilators in first-trimester surgical abortion is unclear. Although cervical priming results in reduced abortion time and improved provider ease, it requires a delay of at least 1 to 3 h and may confer side effects. The Society of Family Planning does not recommend routine cervical priming for first-trimester suction abortion but recommends limiting consideration of cervical priming for women at increased risk of complications from cervical dilation, including those late in the first trimester, adolescents and women in whom cervical dilation is expected to be challenging. Copyright © 2016 Elsevier Inc. All rights reserved.

Balloon dilatation of nasopharyngeal stenosis in a dog.

PubMed

Berent, Allyson C; Kinns, Jennifer; Weisse, Chick

2006-08-01

A dog was examined because of a 6-month history of upper airway stridor that began after postoperative regurgitation of gastric contents. Constant stridor was evident during inspiration and expiration, although it was worse during inspiration. The stridor was no longer evident when the dog's mouth was manually held open. Computed tomography, rhinoscopy, and fluoroscopy were used to confirm a diagnosis of nasopharyngeal stenosis. The dog was anesthetized, and balloon dilatation of the stenosis was performed. Prednisone was prescribed for 4 weeks after the procedure to decrease fibrous tissue formation. Although the dog was initially improved, signs recurred 3.5 weeks later, and balloon dilatation was repeated. This time, however, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Two months later, although the dog did not have clinical signs of stridor, a third dilatation procedure was performed because mild stenosis was seen on follow-up computed tomographic images; again, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Three and 6 months after the third dilatation procedure, the dog reportedly was clinically normal. Findings suggest that balloon dilatation may be an effective treatment for nasopharyngeal stenosis in dogs.

[Pupillary reactions and eye hemodynamics in patients with diabetes mellitus with different glycemic levels].

PubMed

Sdobnikova, S V; Dorokhina, N Iu; Gupalo, O D; Krivosheeva, N V

2010-01-01

Pupillary reactions and hemodynamic parameters in the ophthalmic and central retinal arteries were studied in patients with types 1 and 2 diabetes mellitus. The pupillary dilatation test in the dark and 2.5% irifrin and 1% mydriacyl tests revealed a reduction in the papillary dilatation amplitude in hyperglycemia in patients with diabetic retinopathy. The amplitude of pupillary dilatation did not change during all pupil reactions in patients without diabetic retinopathy with a glycemic gradient. Pupillary dysfunction was detected in patients with diabetic retinopathy, which is a poor predictor for microangiopathy. Color Doppler mapping is a technique for studying blood flow, which is widely used in most of research institutions now. The procedure for studying the ocular microcirculatory bed in relation to blood glucose levels is an innovation in examining eye hemodynamics in patients with diabetes mellitus.

Parallel decrease in arterial distensibility and in endothelium-dependent dilatation in young women with a history of pre-eclampsia.

PubMed

Pàez, Olga; Alfie, José; Gorosito, Marta; Puleio, Pablo; de Maria, Marcelo; Prieto, Noemì; Majul, Claudio

2009-10-01

Pre-eclampsia not only complicates 5 to 8% of pregnancies but also increases the risk of maternal cardiovascular disease and mortality later in life. We analyzed three different aspects of arterial function (pulse wave velocity, augmentation index, and flow-mediated dilatation), in 55 nonpregnant, normotensive women (18-33 years old) according to their gestational history: 15 nulliparous, 20 with a previous normotensive, and 20 formerly pre-eclamptic pregnancy. Former pre-eclamptic women showed a significantly higher augmentation index and pulse wave velocity (P < 0.001 and P < 0.05, respectively) and lower flow-mediated dilatation (p = 0.01) compared to control groups. In contrast, sublingual nitroglycerine elicited a comparable vasodilatory response in the three groups. The augmentation index correlated significantly with pulse wave velocity and flow-mediated dilatation (R = 0.28 and R = -0.32, respectively, P < 0.05 for both). No significant correlations were observed between augmentation index or flow-mediated dilatation with age, body mass index (BMI), brachial blood pressure, heart rate, or metabolic parameters (plasma cholesterol, glucose, insulin, or insulin resistance). Birth weight maintained a significantly inverse correlation with the augmentation index (R = -0.51, p < 0.002) but not with flow-mediated dilatation. Our findings revealed a parallel decrease in arterial distensibility and endothelium-dependent dilatation in women with a history of pre-eclampsia compared to nulliparous women and women with a previous normal pregnancy. A high augmentation index was the most consistent alteration associated with a history of pre-eclampsia. The study supports the current view that the generalized arterial dysfunction associated with pre-eclampsia persists subclinically after delivery.

Echocardiographic assessment of the aortic root dilatation in adult patients after tetralogy of Fallot repair.

PubMed

Cruz, Cristina; Pinho, Teresa; Lebreiro, Ana; Silva Cardoso, José; Maciel, Maria Júlia

2013-06-01

Transthoracic echocardiography is an important tool after tetralogy of Fallot repair, of which aortic root dilatation is a recognized complication. In this study we aimed to assess its prevalence and potential predictors. We consecutively assessed adult patients by transthoracic echocardiography after tetralogy of Fallot repair, and divided them into two groups based on the maximum internal aortic diameter at the sinuses of Valsalva in parasternal long-axis view: group 1 with aortic root dilatation (≥38 mm) and group 2 without dilatation (<38 mm). A total of 53 patients were included, mean age 32±10 years, with a mean time since surgery of 23±7 years. An aortopulmonary shunt had been performed prior to complete repair in 25 patients, and a transannular patch was used in 19 patients. Aortic root measurement was possible in all patients. Aortic root dilatation was identified in eight patients (15%), all male. Male gender (p=0.001), body surface area (1.93±0.10 vs. 1.70±0.20 m(2), p=0.03) and increased left ventricular end-diastolic diameter (p=0.005) were predictors of aortic root dilatation. None of the surgical variables studied were predictors of aortic root dilatation. The prevalence of aortic root dilatation in this cohort was low and male gender was a predictor of its occurrence. The type of repair and time to surgery did not influence its occurrence. Quantification of aortic root diameter is possible by transthoracic echocardiography; we suggest indexing it to body surface area in clinical practice. Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Assessing first-stage labor progression and its relationship to complications.

PubMed

Hamilton, Emily F; Warrick, Philip A; Collins, Kathleen; Smith, Samuel; Garite, Thomas J

2016-03-01

New labor curves have challenged the traditional understanding of the general pattern of dilation and descent in labor. They also revealed wide variation in the time to advance in dilation. An interval of arrest such as 4 hours did not fall beyond normal limits until dilation had reached 6 cm. Thus, the American College of Obstetricians and Gynecologists/Society for Maternal-Fetal Medicine first-stage arrest criteria, based in part on these findings, are applicable only in late labor. The wide range of time to dilate is unavoidable because cervical dilation has neither a precise nor direct relationship to time. Newer statistical techniques (multifactorial models) can improve precision by incorporating several factors that are related directly to labor progress. At each examination, the calculations adapt to the mother's current labor conditions. They produce a quantitative assessment that is expressed in percentiles. Low percentiles indicate potentially problematic labor progression. The purpose of this study was to assess the relationship between first-stage labor progress- and labor-related complications with the use of 2 different assessment methods. The first method was based on arrest of dilation definitions. The other method used percentile rankings of dilation or station based on adaptive multifactorial models. We included all 4703 cephalic-presenting, term, singleton births with electronic fetal monitoring and cord gases at 2 academic community referral hospitals in 2012 and 2013. We assessed electronic data for route of delivery, all dilation and station examinations, newborn infant status, electronic fetal monitoring tracings, and cord blood gases. The labor-related complication groups included 272 women with cesarean delivery for first-stage arrest, 558 with cesarean delivery for fetal heart rate concerns, 178 with obstetric hemorrhage, and 237 with neonatal depression, which left 3004 women in the spontaneous vaginal birth group. Receiver operating characteristic curves were constructed for each assessment method by measurement of the sensitivity for each complication vs the false-positive rate in the normal reference group. The duration of arrest at ≥6 cm dilation showed poor levels of discrimination for the cesarean delivery interventions (area under the curve, 0.55-0.65; P < .01) and no significant relationship to hemorrhage or neonatal depression. The dilation and station percentiles showed high discrimination for the cesarean delivery-related outcomes (area under the curve, 0.78-0.93; P < .01) and low discrimination for the clinical outcomes of hemorrhage and neonatal depression (area under the curve, 0.58-0.61; P < .01). Duration of arrest of dilation at ≥6 cm showed little or no discrimination for any of the complications. In comparison, percentile rankings that were based on the adaptive multifactorial models showed much higher discrimination for cesarean delivery interventions and better, but low discrimination for hemorrhage. Adaptive multifactorial models present a different method to assess labor progress. Rather than "pass/fail" criteria that are applicable only to dilation in late labor, they produce percentile rankings, assess 2 essential processes for vaginal birth (dilation and descent), and can be applied from 3 cm onward. Given the limitations of labor-progress assessment based solely on the passage of time and because of the extreme variation in decision-making for cesarean delivery for labor disorders, the types of mathematic analyses that are described in this article are logical and promising steps to help standardize labor assessment. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Achondroplasia in children: correlation of ventriculomegaly, size of foramen magnum and jugular foramina, and emissary vein enlargement.

PubMed

Bosemani, Thangamadhan; Orman, Gunes; Hergan, Benedikt; Carson, Kathryn A; Huisman, Thierry A G M; Poretti, Andrea

2015-01-01

Achondroplasia is a skeletal dysplasia with diminished growth of the skull base secondary to defective enchondral bone formation. This leads to narrowing of the foramen magnum and jugular foramina, which further leads to ventricular dilatation and prominence of the emissary veins. The primary goal of our study was to determine a correlation between the degree of ventricular dilatation, jugular foramina and foramen magnum narrowing, as well as emissary vein enlargement. Conventional T2-weighted MR images were evaluated for surface area of the foramen magnum and jugular foramina, ventricular dilatation, and emissary veins enlargement in 16 achondroplasia patients and 16 age-matched controls. Ratios were calculated for the individual parameters using median values from age-matched control groups to avoid age as a confounder. Compared to age-matched controls, in children with achondroplasia, the surface area of the foramen magnum (median 0.50 cm(2), range 0.23-1.37 cm(2) vs. 3.14 cm(2), 1.83-6.68 cm(2), p < 0.001) and jugular foramina (median 0.02 cm(2), range 0-0.10 cm(2) vs. 0.21 cm(2), 0.03-0.61 cm(2), p < 0.001) were smaller, whereas ventricular dilatation (0.28, 0.24-0.4 vs. 0.26, 0.21-0.28, p < 0.001) and enlargement of emissary veins (6, 0-11 vs. 0, p < 0.001) were higher. Amongst the patients, Spearman correlation and multiple regression analysis did not reveal correlation for severity between the individual parameters. Our study suggests that in children with achondroplasia, (1) the variation in ventricular dilatation may be related to an unquantifiable interdependent relationship of emissary vein enlargement, venous channel narrowing, and foramen magnum compression and (2) stable ventricular size facilitated by interdependent factors likely obviates the need for ventricular shunt placement.

Computational fluid dynamics simulation of pressure and velocity distribution inside Meniere’s diseased vestibular system

NASA Astrophysics Data System (ADS)

Shamsuddin, N. F. H.; Isa, N. M.; Taib, I.; Mohammed, A. N.

2017-09-01

Meniere’s disease or known as endolymphatic hydrops is an incurable vestibular disorder of the inner ear. This is due to the excessive fluid build-up in the endolymphatic sac which causing the vestibular endolymphatic membrane to start stretching. Although this mechanism has been widely accepted as the likely mechanism of Meniere’s syndrome, the reason for its occurrence remains unclear. Thus, the aims of this study to investigate the critical parameters of fluid flow in membranous labyrinth that is influencing instability of vestibular system. In addition, to visualise the flow behaviour between a normal membranous labyrinth and dilated membranous labyrinth in Meniere’s disease in predicting instability of vestibular system. Three dimensional geometry of endolymphatic sac is obtained from Magnetic Resonance Images (MRI) and reconstructed using commercial software. As basis of comparison the two different model of endolymphatic sac is considered in this study which are normal membranous labyrinth for model I and dilated membranous labyrinth for model II. Computational fluid dynamics (CFD) method is used to analyse the behaviour of pressure and velocity flow in the endolymphatic sac. The comparison was made in terms of pressure distribution and velocity profile. The results show that the pressure for dilated membranous labyrinth is greater than normal membranous labyrinth. Due to abnormally pressure in the vestibular system, it leads to the increasing value of the velocity at dilated membranous labyrinth while at the normal membranous labyrinth the velocity values decreasing. As a conclusion by changing the parameters which is pressure and velocity can significantly affect to the instability of vestibular system for Meniere’s disease.

Risk factors associated with refractoriness to esophageal dilatation for benign dysphagia.

PubMed

Rodrigues-Pinto, Eduardo; Pereira, Pedro; Ribeiro, Armando; Lopes, Susana; Moutinho-Ribeiro, Pedro; Silva, Marco; Peixoto, Armando; Gaspar, Rui; Macedo, Guilherme

2016-06-01

Benign esophageal strictures need repeated dilatations to relieve dysphagia. Literature is scarce on the risk factors for refractoriness of these strictures. This study aimed to assess the risk factors associated with refractory strictures. This is a retrospective study of patients with benign esophageal strictures who were referred for esophageal dilatation over a period of 3 years. A total of 327 esophageal dilatations were performed in 103 patients; 53% of the patients reported dysphagia for liquids. Clinical success was achieved in 77% of the patients. There was a need for further dilatations in 54% of patients, being more frequent in patients with dysphagia for liquids [78 vs. 64%, P=0.008, odds ratio (OR) 1.930], in those with caustic strictures (89 vs. 70%, P=0.007, OR 3.487), and in those with complex strictures (83 vs. 70%, P=0.047, OR 2.132). Caustic strictures, peptic strictures, and complex strictures showed statistical significance in the multivariate analysis. Time until subsequent dilatations was less in patients with dysphagia for liquids (49 vs. 182 days, P<0.001), in those with peptic strictures (49 vs. 98 days, P=0.004), in those with caustic strictures (49 vs. 78 days, P=0.005), and in patients with complex strictures (47 vs. 80 days P=0.009). In multivariate analysis, further dilatations occurred earlier in patients with dysphagia for liquids [hazard ratio (HR) 1.506, P=0.004], in those with peptic strictures (HR 1.644, P=0.002), in those with caustic strictures (HR 1.581, P=0.016), and in patients with complex strictures (HR 1.408, P=0.046). Caustic, peptic, and complex strictures were associated with a greater need for subsequent dilatations. Time until subsequent dilatations was less in patients with dysphagia for liquids and in those with caustic, peptic, and complex strictures.

'X-ray'-free balloon dilation for totally ultrasound-guided percutaneous nephrolithotomy.

PubMed

Zhou, Tie; Chen, Guanghua; Gao, Xiaofeng; Zhang, Wei; Xu, Chuanliang; Li, Lei; Sun, Yinghao

2015-04-01

The objective of the study was to evaluate the feasibility and safety of balloon dilation for 'X-ray'-free ultrasound-guided percutaneous nephrolithotomy (PCNL). From January 2012 to December 2012, patients underwent 'X-ray'-free ultrasound-guided PCNL with Amplatz dilator (Group A). From January 2013 to April 2014, patients underwent 'X-ray'-free ultrasound-guided PCNL with balloon dilator (Group B). For balloon dilation, a 10 F fascial dilator was used to dilate the tract. Subsequently, the 6 F nephrostomy balloon (8 mm in diameter) was indwelled along the guidewire with a marked length equal to the dilation depth. Under the monitoring of ultrasound, the location of balloon was secured and disappearance of balloon waist was confirmed when the balloon was inflated at a pressure of 20 atm. A total of 163 patients were involved in this study. Of 81 procedures in Group A, 45 procedures were performed by a senior urologist while 36 procedures by a resident. Of 82 patients in Group B, 47 procedures were performed by the same senior urologist while 35 procedures by another resident. For the senior urologist, there was no statistically significant difference between two groups in calyx of entry, stone-free rate, decline of hemoglobin and hematocrit, operation time and hospitalization. But for the residents, there was less decline of hemoglobin and hematocrit, tract development time and hospitalization in Group B compared to Group A (0.6 vs. 1.7 g/dl, p = 0.001; 2.3% vs. 5.5%, p = 0.003; 10.1 vs. 11.0 min, p = 0.027; 7.8 vs. 13.9 days, p < 0.001). Balloon dilation method introduced in this study is compensable for tract development when 'X-ray'-free ultrasound-guided PCNL is performed. Modified techniques make totally ultrasound guidance for PCNL feasible, easy and safe. In addition, such a procedure is preferable for initial operators because of less hemorrhage complication.

Endoscopic dilation for treatment of anastomotic leaks following transhiatal esophagectomy.

PubMed

Bhasin, D K; Sharma, B C; Gupta, N M; Sinha, S K; Singh, K

2000-06-01

Anastomotic leak is a known complication after transhiatal esophagectomy (THE) and cervical esophagogastric anastomosis. Conservative management takes a long time to heal such leaks. We assessed the role of endoscopic dilation in patients with anastomotic leak following THE. Eight consecutive patients (seven men, one woman; mean age 51) with anastomotic leak following THE were subjected to endoscopic dilation using Savary Gilliard dilators of 7-15 mm diameter. The mean interval between surgery and detection of leak was 9 days (range 5-22 days) and dilation was performed at a mean interval of 11.4 days (range 1-20 days) after detection of the leak. Drainage from fistulas stopped completely after 1-8 days (mean 3 days). X-ray with water soluble contrast showed closure of the fistula in all cases. Duration of follow-up ranged from 2 to 12 months. Anastomotic strictures developed in three patients. These patients required three sessions each of repeat dilation, and were alive at follow-up periods of 2, 4, and 12 months, respectively. One patient developed recurrence of growth at an anastomotic site. Four patients died because of distant metastasis. Bougie dilation of anastomotic sites is a safe and effective technique for the healing of anastomotic leaks following THE. However there is a need for a prospective randomized trial comparing endoscopic dilation with no dilation in patients with anastomotic leaks following THE.

Effects of attention on the speech reception threshold and pupil response of people with impaired and normal hearing.

PubMed

Koelewijn, Thomas; Versfeld, Niek J; Kramer, Sophia E

2017-10-01

For people with hearing difficulties, following a conversation in a noisy environment requires substantial cognitive processing, which is often perceived as effortful. Recent studies with normal hearing (NH) listeners showed that the pupil dilation response, a measure of cognitive processing load, is affected by 'attention related' processes. How these processes affect the pupil dilation response for hearing impaired (HI) listeners remains unknown. Therefore, the current study investigated the effect of auditory attention on various pupil response parameters for 15 NH adults (median age 51 yrs.) and 15 adults with mild to moderate sensorineural hearing loss (median age 52 yrs.). Both groups listened to two different sentences presented simultaneously, one to each ear and partially masked by stationary noise. Participants had to repeat either both sentences or only one, for which they had to divide or focus attention, respectively. When repeating one sentence, the target sentence location (left or right) was either randomized or blocked across trials, which in the latter case allowed for a better spatial focus of attention. The speech-to-noise ratio was adjusted to yield about 50% sentences correct for each task and condition. NH participants had lower ('better') speech reception thresholds (SRT) than HI participants. The pupil measures showed no between-group effects, with the exception of a shorter peak latency for HI participants, which indicated a shorter processing time. Both groups showed higher SRTs and a larger pupil dilation response when two sentences were processed instead of one. Additionally, SRTs were higher and dilation responses were larger for both groups when the target location was randomized instead of fixed. We conclude that although HI participants could cope with less noise than the NH group, their ability to focus attention on a single talker, thereby improving SRTs and lowering cognitive processing load, was preserved. Shorter peak latencies could indicate that HI listeners adapt their listening strategy by not processing some information, which reduces processing time and thereby listening effort. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Effects of different dietary protein intakes on body composition and vascular reactivity.

PubMed

Ferrara, L A; Innelli, P; Palmieri, V; Limauro, S; De Luca, G; Ferrara, F; Liccardo, E; Celentano, A

2006-05-01

To assess the effects of a diet rich in protein of animal origin in comparison to one with a protein intake of about 15% of the total daily calories on body composition and arterial function. Randomized prospective study with parallel groups. Body weight (BW), blood pressure (BP), main parameters of carbohydrate and lipid metabolism, body mass composition by bioelectrical impedance analysis, forearm blood flow at rest and in the postischaemic phase by strain gauge plethysmography and flow-mediated dilation of the brachial artery by echography were measured at baseline and after 6 months of the dietary intervention. In total, 15 clinically healthy male volunteers, regularly performing a mixed training three times weekly for 90 min. The participants were randomly prescribed a diet with high (1.9 g/kg BW) or normal (1.3 g/kg BW) protein content. Differences between means were evaluated by the t-tests for paired or unpaired data and by one way analysis of variance. The strength of correlation between variables was investigated by bivariate Pearson correlation. Serum cholesterol significantly decreased with both diets in comparison to baseline values, whereas BW was slightly but significantly reduced only by the high-protein (HP) diet. No change was detected in BP and the other metabolic parameters. Body mass composition was not significantly modified by either diet. On the other hand, postischaemic flow-mediated dilation of the brachial artery was enhanced by the sole normal protein (NP) diet, whereas no change in the forearm blood flow, both at rest and in the postischaemic phase, was detected. These preliminary results indicate that HP diet was found to be not useful in increasing the muscle mass in comparison to a NP intake. In contrast to this, the latter diet seems to enhance the endothelial function of the arterial vessels with a more pronounced dilatation of the lumen in response to the increase in blood flow.

Improved pupil dilation with medication-soaked pledget sponges.

PubMed

Weddle, Celeste; Thomas, Nikki; Dienemann, Jacqueline

2013-08-01

Use of multiple preoperative drops for pupil dilation has been shown to be inexact, to delay surgery, and to cause dissatisfaction among perioperative personnel. This article reports on an evidence-based, quality improvement project to locate and appraise research on improved effectiveness and efficiency of mydriasis (ie, pupillary dilation), and the subsequent implementation of a pledget-sponge procedure for pupil dilation at one ambulatory surgery center. Project leaders used an evidence-based practice model to assess the problem, research options for improvement, define goals, and implement a pilot project to test the new dilation technique. Outcomes from the pilot project showed a reduced number of delays caused by poor pupil dilation and a decrease in procedure turnover time. The project team solicited informal feedback from preoperative nurses, which reflected increased satisfaction in preparing patients for cataract procedures. After facility administrators and surgeons accepted the procedure change, it was adopted for preoperative use for all patients undergoing cataract surgery at the ambulatory surgery center. Copyright © 2013 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Ultrasound Guidance for Renal Tract Access and Dilation Reduces Radiation Exposure during Percutaneous Nephrolithotomy

PubMed Central

2016-01-01

Purposes. To present our series of 38 prone percutaneous nephrolithotomy procedures performed with renal access and tract dilation purely under ultrasound guidance and describe the benefits and challenges accompanying this approach. Methods. Thirty-eight consecutive patients presenting for percutaneous nephrolithotomy for renal stone removal were included in this prospective cohort study. Ultrasonographic imaging in the prone position was used to obtain percutaneous renal access and guide tract dilation. Fluoroscopic screening was used only for nephrostomy tube placement. Preoperative, intraoperative, and postoperative procedural and patient data were collected for analysis. Results. Mean age of patients was 52.7 ± 17.2 years. Forty-five percent of patients were male with mean BMI of 26.1 ± 7.3 and mean stone size of 27.2 ± 17.6 millimeters. Renal puncture was performed successfully with ultrasonographic guidance in all cases with mean puncture time of 135.4 ± 132.5 seconds. Mean dilation time was 11.5 ± 3.8 min and mean stone fragmentation time was 37.5 ± 29.0 min. Mean total operative time was 129.3 ± 41.1. No patients experienced any significant immediate postoperative complication. All patients were rendered stone-free and no additional secondary procedures were required. Conclusions. Ultrasound guidance for renal access and tract dilation in prone percutaneous nephrolithotomy is a feasible and effective technique. It can be performed safely with significantly reduced fluoroscopic radiation exposure to the patient, surgeon, and intraoperative personnel. PMID:27042176

Enalapril and losartan are more effective than carvedilol in preventing dilated cardiomyopathy in the Syrian cardiomyopathic hamster.

PubMed

Crespo, Maria J; Cruz, Nildris; Altieri, Pablo I; Escobales, Nelson

2008-09-01

To assess the role of the renin-angiotensin (RAS) and adrenergic systems in the development and progression of dilated cardiomyopathy in the Syrian cardiomyopathic hamster (SCH), echocardiographic parameters were evaluated in 6-month-old animals after 5 months of treatment with enalapril (25 mg/kg/day) plus losartan (10 mg/kg/day), or with carvedilol (1 mg/kg/day). Cardiac output indexes (COI) increased by 53% after RAS blockade and by 20% after beta-blockade in SCH. Moreover, LVEDV and LVESV decreased 30% and 62%, respectively (P < .05) during RAS blockade, whereas ejection fraction (EF) increased by 48%. By contrast, carvedilol reduced LVESV by only 28% (P < .05) and increased EF by only 15% (P < .05). These results suggest that RAS activation plays a critical role in the development of cardiac dysfunction in SCH and that suppression of RAS may be more effective than beta-blockade in retarding the development of cardiomyopathy in SCH. Owing to timing (pre-heart failure stage) and to the single dose protocol, the implications of this study for human subjects remain to be clarified.

Additively Manufactured Pneumatically Driven Skin Electrodes.

PubMed

Schubert, Martin; Schmidt, Martin; Wolter, Paul; Malberg, Hagen; Zaunseder, Sebastian; Bock, Karlheinz

2017-12-23

Telemedicine focuses on improving the quality of health care, particularly in out-of-hospital settings. One of the most important applications is the continuous remote monitoring of vital parameters. Long-term monitoring of biopotentials requires skin-electrodes. State-of-the-art electrodes such as Ag/AgCl wet electrodes lead, especially during long-term application, to complications, e.g., skin irritations. This paper presents a low-cost, on-demand electrode approach for future long-term applications. The fully printed module comprises a polymeric substrate with electrodes on a flexible membrane, which establishes skin contact only for short time in case of measurement. The membranes that produce airtight seals for pressure chambers can be pneumatically dilated and pressed onto the skin to ensure good contact, and subsequently retracted. The dilatation depends on the pressure and membrane thickness, which has been tested up to 150 kPa. The electrodes were fabricated in screen and inkjet printing technology, and compared during exemplary electrodermal activity measurement (EDA). The results show less amplitude compared to conventional EDA electrodes but similar behavior. Because of the manufacturing process the module enables high individuality for future applications.

Acute stent recoil and optimal balloon inflation strategy: an experimental study using real-time optical coherence tomography.

PubMed

Kitahara, Hideki; Waseda, Katsuhisa; Yamada, Ryotaro; Otagiri, Kyuhachi; Tanaka, Shigemitsu; Kobayashi, Yuhei; Okada, Kozo; Kume, Teruyoshi; Nakagawa, Kaori; Teramoto, Tomohiko; Ikeno, Fumiaki; Yock, Paul G; Fitzgerald, Peter J; Honda, Yasuhiro

2016-06-12

Our aim was to evaluate stent expansion and acute recoil at deployment and post-dilatation, and the impact of post-dilatation strategies on final stent dimensions. Optical coherence tomography (OCT) was performed on eight bare metal platforms of drug-eluting stents (3.0 mm diameter, n=6 for each) during and after balloon inflation in a silicone mock vessel. After nominal-pressure deployment, a single long (30 sec) vs. multiple short (10 sec x3) post-dilatations were performed using a non-compliant balloon (3.25 mm, 20 atm). Stent areas during deployment with original delivery systems were smaller in stainless steel stents than in cobalt-chromium and platinum-chromium stents (p<0.001), whereas subsequent acute recoil was comparable among the three materials. At post-dilatation, acute recoil was greater in cobalt-chromium and platinum-chromium stents than in stainless steel stents (p<0.001), resulting in smaller final stent areas in cobalt-chromium and platinum-chromium stents than in stainless steel stents (p<0.001). In comparison between conventional and latest-generation cobalt-chromium stents, stent areas were not significantly different after both deployment and post-dilatation. With multiple short post-dilatations, acute recoil was significantly improved from first to third short inflation (p<0.001), achieving larger final area than a single long inflation, despite stent materials/designs (p<0.001). Real-time OCT revealed significant acute recoil in all stent types. Both stent materials/designs and post-dilatation strategies showed a significant impact on final stent expansion.

Ultrasonography-guided percutaneous nephrolithotomy with Chinese one-shot tract dilation technique based on stimulated diuresis: A report of 67 cases.

PubMed

Shi, Ying; Liang, Hua-Geng; Yang, Xiong; Hai, Bo; Wang, Liang; Xing, Yi-Fei; Ju, Wen; Zeng, Fu-Qing; Zhang, Xiao-Ping; Li, Wen-Cheng

2016-12-01

The safety and effectiveness of a novel Chinese one-shot dilation technique based on stimulated diuresis for percutaneous nephrolithotomy (PCNL) were investigated. After the feasibility of the Chinese one-shot dilation based on stimulated diuresis was verified by an animal study, this technique was applied in the clinical practice. A total of 67 patients in our department underwent the modified PCNL from July 2014 to June 2015. After the renal infundibulum was distended by stimulated diuresis, the kidney was punctured under the ultrasonographic guidance via the fornix of the target calyx. The working channel was dilated using a special designed pencil-shaped fascial dilator. The successful access rate, nephrostomy tract creation time, pre- and postoperative hemoglobin values and serum creatinine concentrations, stone-free rate and complications were recorded and analyzed. The renal infundibulum was successfully distended in all of the patients by the diuresis treatment. Under the ultrasonographic guidance, the successful access rate was 100% and the mean tract creation time was 2.0 min (range: 1.5-5.0 min). The stone-free rate right after surgery was 91.0%. Although the postoperative hemoglobin was significantly reduced (P<0.01), transfusion was not clinically necessary. There was no significant difference in serum creatinine concentrations before and after operation (P>0.05). No severe complication occurred during or after the PCNL. It was suggested that this Chinese one-shot dilation technique based on stimulated diuresis is an efficient and safe innovation for PCNL, and is even helpful for those patients with non-dilated pelvicaliceal systems.

Quantitative analysis of iris changes after physiologic and pharmacologic mydriasis in a rural Chinese population.

PubMed

Zhang, Ye; Li, Si Zhen; Li, Lei; He, Ming Guang; Thomas, Ravi; Wang, Ning Li

2014-04-24

To estimate and compare the change in iris cross-sectional area (IA) and iris volume (IV) following physiologic and pharmacologic pupil dilation in primary angle closure suspects (PACS) and normal subjects. Anterior segment-optical coherence tomography (AS-OCT) measurements in light, dark, and following pharmacologic dilation were obtained on 186 PACS and 224 normal subjects examined during the 5-year follow-up of the Handan Eye Study. Iris cross-sectional area, IV, and other biometric parameters calculated using the Zhongshan angle assessment program in the right eyes of all subjects were analyzed. The mean IA and IV decreased in dark compared with light and after pharmacologic dilation in both PACS and normal eyes. This change was statistically significant in normal eyes: light versus pharmacologic dilation for IA (P = 0.038) and for IV, both light versus dark (P = 0.031) and light versus pharmacologic dilation (P = 0.012). A longer axial length (P = 0.028) and a greater change in pupil diameter (PD) (P < 0.001) were associated with a larger decrease of IA for the light to dark comparison. A diagnosis of normal eyes (P = 0.011), larger PD in dark (P = 0.001), and a larger change in PD (P = 0.001) were associated with a larger decrease of IV from light to dark. The differences in iris behavior between PACS and normal rural Chinese subjects following physiologic or pharmacologic pupillary dilation may help provide insights into the pathogenesis of angle closure. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Endoscopic Management of Idiopathic Subglottic Stenosis.

PubMed

Shabani, Sepehr; Hoffman, Matthew R; Brand, William T; Dailey, Seth H

2017-02-01

To describe a homogeneous idiopathic subglottic stenosis (ISS) population undergoing endoscopic balloon dilation and evaluate factors affecting inter-dilation interval (IDI). Retrospective review of 37 patients. Co-morbidity prevalence versus normal population was evaluated using chi-square tests. Correlations were evaluated using Pearson product moment tests. Independent samples t tests/rank sum tests assessed differences between groups of interest. All patients were female aged 45.9 ± 15.4 years at diagnosis. Four required a tracheotomy during management. Most prevalent co-morbidity was gastroesophageal reflux disease (GERD) (64.9%; P = .036). Body mass indices (BMI) at first and most recent dilation were 29.8 and 30.8 ( P = .564). Degree of stenosis before first dilation was 53 ± 14%. Patients underwent 3.8 ± 1.8 dilations (range, 1-11). Average IDI was 635 ± 615 days (range, 49-3130 days), including 556 ± 397 days for patients receiving concomitant steroid injection and 283 ± 36 for those who did not ( P = .079). Inter-dilation interval was not correlated with BMI ( r = 0.0486; P = .802) or number of co-morbidities ( r = -0.225, P = .223). Most patients with ISS can be managed endoscopically, and IDI may be increased with steroid injection. Gastroesophageal reflux disease is a common co-morbidity. Body mass index did not change over time despite potential effects on exercise tolerance; BMI did not affect IDI. Methods to determine optimal timing for next intervention are warranted.

Competitive adsorption from mixed hen egg-white lysozyme/surfactant solutions at the air-water interface studied by tensiometry, ellipsometry, and surface dilational rheology.

PubMed

Alahverdjieva, V S; Grigoriev, D O; Fainerman, V B; Aksenenko, E V; Miller, R; Möhwald, H

2008-02-21

The competitive adsorption at the air-water interface from mixed adsorption layers of hen egg-white lysozyme with a non-ionic surfactant (C10DMPO) was studied and compared to the mixture with an ionic surfactant (SDS) using bubble and drop shape analysis tensiometry, ellipsometry, and surface dilational rheology. The set of equilibrium and kinetic data of the mixed solutions is described by a thermodynamic model developed recently. The theoretical description of the mixed system is based on the model parameters for the individual components.

Special Relativity in Week One: 3) Introducing the Lorentz Contraction

NASA Astrophysics Data System (ADS)

Huggins, Elisha

2011-05-01

This is the third of four articles on teaching special relativity in the first week of an introductory physics course.1,2 With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie "Time Dilation, an Experiment with Mu-Mesons" by David Frisch and James Smith.3,4 The movie demonstrates that time dilation and the Lorentz contraction are essentially two sides of the same coin. Here we take the muon's point of view for a more intuitive understanding of the Lorentz contraction, and use the results of the movie to provide an insight into the way we interpret experimental results involving special relativity.

Long-term effect of urethral dilatation and internal urethrotomy for urethral strictures.

PubMed

Veeratterapillay, Rajan; Pickard, Rob S

2012-11-01

Urethral dilatation and direct visual internal urethrotomy (DVIU) are widely used minimally invasive options to manage men with urethral strictures. Advances in open urethroplasty with better long-term cure rates have fuelled the continuing debate as to which treatment is best for primary and recurrent urethral strictures. We reviewed recent literature to identify contemporary practice of urethral dilatation and DVIU and the long-term outcome of these procedures. Systematic literature search for the period January 2010 to December 2011 showed that urethral dilatation and DVIU remain frequently used treatment options as confirmed by surveys of urologists in the USA and the Netherlands. Multiple reports of laser DVIU confirm the safety of this approach but long-term data were lacking. Stricture free rates from urethra dilatation and DVIU vary from 10 to 90% at 12 months, although adjunctive intermittent self-dilatation can reduce time to recurrence. Although quality-of-life benefit appears good in the short term, repeated procedures may harm sexual function in the long-term. Urethral dilatation and DVIU remain widely used in urethral stricture management but high-level comparative evidence of benefit and harms against urethroplasty in the short and long-term is still lacking.

Randomized controlled trial comparing esophageal dilation to no dilation among adults with esophageal eosinophilia and dysphagia.

PubMed

Kavitt, R T; Ates, F; Slaughter, J C; Higginbotham, T; Shepherd, B D; Sumner, E L; Vaezi, M F

2016-11-01

The role of esophageal dilation in patients with esophageal eosinophilia with dysphagia remains unknown. The practice of dilation is currently based on center preferences and expert opinion. The aim of this study is to determine if, and to what extent, dysphagia improves in response to initial esophageal dilation followed by standard medical therapies. We conducted a randomized, blinded, controlled trial evaluating adult patients with dysphagia and newly diagnosed esophageal eosinophilia from 2008 to 2013. Patients were randomized to dilation or no dilation at time of endoscopy and blinded to dilation status. Endoscopic features were graded as major and minor. Subsequent to randomization and endoscopy, all patients received fluticasone and dexlansoprazole for 2 months. The primary study outcome was reduction in overall dysphagia score, assessed at 30 and 60 days post-intervention. Patients with severe strictures (less than 7-mm esophageal diameter) were excluded from the study. Thirty-one patients were randomized and completed the protocol: 17 randomized to dilation and 14 to no dilation. Both groups were similar with regard to gender, age, eosinophil density, endoscopic score, and baseline dysphagia score. The population exhibited moderate to severe dysphagia and moderate esophageal stricturing at baseline. Overall, there was a significant (P < 0.001) but similar reduction in mean dysphagia score at 30 and 60 days post-randomization compared with baseline in both groups. No significant difference in dysphagia scores between treatment groups after 30 (P = 0.93) or 60 (P = 0.21) days post-intervention was observed. Esophageal dilation did not result in additional improvement in dysphagia score compared with treatment with proton pump inhibitor and fluticasone alone. In patients with symptomatic esophageal eosinophilia without severe stricture, dilation does not appear to be a necessary initial treatment strategy. © 2015 International Society for Diseases of the Esophagus.

The Amount of Time Dilation for Visual Flickers Corresponds to the Amount of Neural Entrainments Measured by EEG.

PubMed

Hashimoto, Yuki; Yotsumoto, Yuko

2018-01-01

The neural basis of time perception has long attracted the interests of researchers. Recently, a conceptual model consisting of neural oscillators was proposed and validated by behavioral experiments that measured the dilated duration in perception of a flickering stimulus (Hashimoto and Yotsumoto, 2015). The model proposed that flickering stimuli cause neural entrainment of oscillators, resulting in dilated time perception. In this study, we examined the oscillator-based model of time perception, by collecting electroencephalography (EEG) data during an interval-timing task. Initially, subjects observed a stimulus, either flickering at 10-Hz or constantly illuminated. The subjects then reproduced the duration of the stimulus by pressing a button. As reported in previous studies, the subjects reproduced 1.22 times longer durations for flickering stimuli than for continuously illuminated stimuli. The event-related potential (ERP) during the observation of a flicker oscillated at 10 Hz, reflecting the 10-Hz neural activity phase-locked to the flicker. Importantly, the longer reproduced duration was associated with a larger amplitude of the 10-Hz ERP component during the inter-stimulus interval, as well as during the presentation of the flicker. The correlation between the reproduced duration and the 10-Hz oscillation during the inter-stimulus interval suggested that the flicker-induced neural entrainment affected time dilation. While the 10-Hz flickering stimuli induced phase-locked entrainments at 10 Hz, we also observed event-related desynchronizations of spontaneous neural oscillations in the alpha-frequency range. These could be attributed to the activation of excitatory neurons while observing the flicker stimuli. In addition, neural activity at approximately the alpha frequency increased during the reproduction phase, indicating that flicker-induced neural entrainment persisted even after the offset of the flicker. In summary, our results suggest that the duration perception is mediated by neural oscillations, and that time dilation induced by flickering visual stimuli can be attributed to neural entrainment.

A case report of percutaneous endoscopic gastrostomy left-side gastropexy to resolve a recurrent gastric dilatation in a dog previously treated with right-side gastropexy for gastric dilatation volvulus.

PubMed

Spinella, Giuseppe; Cinti, Filippo; Pietra, Marco; Capitani, Ombretta; Valentini, Simona

2014-12-01

A 6-year-old, large-breed, female dog was evaluated for gastric dilatation (GD). The dog was affected by GD volvulus, which had been surgically treated with gastric derotation and right incisional gastropexy. Recurrence of GD appeared 36 hours after surgery. The dilatation was immediately treated with an orogastric probe but still recurred 4 times. Therefore, a left-side gastropexy by percutaneous endoscopic gastrostomy (PEG) was performed to prevent intermittent GD. After PEG tube placement, the patient recovered rapidly without side effects. Several techniques of gastropexy have been described as a prophylactic method for gastric dilatation volvulus, but to the authors' knowledge, this is the first report of left-sided PEG gastropexy performed in a case of canine GD recurrence after an incisional right gastropexy. Copyright © 2015 Elsevier Inc. All rights reserved.

Videofluoroscopy-guided balloon dilatation for treatment of severe pharyngeal dysphagia.

PubMed

Yabunaka, Koichi; Konishi, Hideki; Nakagami, Gojiro; Matsuo, Jyunko; Noguchi, Atsushi; Sanada, Hiromi

2015-01-01

Balloon dilatation is a widely accepted technique in the management of esophageal and other types of gastrointestinal strictures, but it is rarely used for the treatment of pharyngeal dysphagia. Therefore, the aim of our prospective study was to evaluate the use of videofluoroscopy-guided balloon dilatation (VGBD) for the treatment of severe pharyngeal dysphagia. The study included 32 stroke patients who had been diagnosed with oral and/or pharyngeal dysphagia. All patients underwent dilatation of the esophageal inlet using a balloon catheter under videofluoroscopic guidance during one or more sessions. Following esophageal dilatation, manual feeding was provided twice weekly. VGBD was effective in 10 out of 32 patients; however, the remaining 22 patients were unable to attempt oral food consumption because aspiration was not completely resolved on videofluoroscopy. According to this case series, VGBD may provide treatment for patients with severe pharyngeal dysphagia, who have not consumed food orally for a long period of time.

Assessment of Fragmentation Performance of Blast-enhanced Explosive Fragmentation Munitions

DTIC Science & Technology

2010-10-01

velocity of the dilating case is not fully clear. Table 1: PAX-Al (18.1% Al) JWL EOS parameters from Stiel, ref. 5. Parameter Mass fraction of Al...the PAX-Al JWL EOS (Jones-Wilkins- Lee Equation of State) parameters for varying the aluminum reaction fractions is given in Table 1. Comparing the...Maryland. [5] L. I. Stiel, 2008-2010, JAGUAR PAX-Al JWL EOS, unpublished work, Polytechnic Institute of New York University, Six MetroTech Center

One-shot dilation in modified supine position for percutaneous nephrolithotomy: experience from over 300 cases.

PubMed

El Harrech, Youness; Abakka, Najib; El Anzaoui, Jihad; Goundale, Omar; Touiti, Driss

2014-07-08

To evaluate the feasibility, safety and efficacy of one-shot dilation (OSD) in modified supine position percutaneous nephrolithotomy (PCNL). A total of 320 PCNL in a total of 291 patients were performed between October 2008 and July 2011. There were no specific exclusion criteria. Patients with kidney anomalies or solitary kidney, with history of renal surgery or extracorporeal shockwave lithotripsy (SWL), those with staghorn calculi or needing more than one access, were eligible for inclusion. Data collected included patient demographics and stone characteristics, access time, radiation exposure, total operating time, preoperative and postoperative hemoglobin concentrations, tract dilatation failures, complications and transfusions. Mean stone size was 38 mm (16-110 mm). The mean time access was 2.1 min (range 0.7-6.2 min). Tract dilatation fluoroscopy time was 25 ± 17 sec. The targeted calix could be entered with a success rate of 97.81%. The mean hemoglobin decrease was -1.17 g/dL ± 0.84. There were no visceral, pleural, collecting systems or vascular injuries. Major complications included, transfusion in 4 (1.25%) patients, pseudoaneurysm with persistent bleeding necessitating nephrectomy in 1 (0.3%) patient and two deaths (0.62%) after surgery. There was no significant difference in successful access and complications between patients with and without previous open surgery and in those with or without staghorn stones (P > .05). The use of one shot and modified supine position combines the advantages of these both methods including less radiation exposure and shorter access and operative time. The one shot dilation is safe, easy to learn, cost effective and offers a potential alternative to the standard devices particularly in developing countries.

Visit-to-visit and 24-h blood pressure variability: association with endothelial and smooth muscle function in African Americans.

PubMed

Diaz, K M; Veerabhadrappa, P; Kashem, M A; Thakkar, S R; Feairheller, D L; Sturgeon, K M; Ling, C; Williamson, S T; Kretzschmar, J; Lee, H; Grimm, H; Babbitt, D M; Vin, C; Fan, X; Crabbe, D L; Brown, M D

2013-11-01

The purpose of this study was to investigate the association of visit-to-visit and 24-h blood pressure (BP) variability with markers of endothelial injury and vascular function. We recruited 72 African Americans who were non-diabetic, non-smoking and free of cardiovascular (CV) and renal disease. Office BP was measured at three visits and 24-h ambulatory BP monitoring was conducted to measure visit-to-visit and 24-h BP variability, respectively. The 5-min time-course of brachial artery flow-mediated dilation and nitroglycerin-mediated dilation were assessed as measures of endothelial and smooth muscle function. Fasted blood samples were analyzed for circulating endothelial microparticles (EMPs). Significantly lower CD31+CD42- EMPs were found in participants with high visit-to-visit systolic blood pressure (SBP) variability or high 24-h diastolic blood pressure (DBP) variability. Participants with high visit-to-visit DBP variability had significantly lower flow-mediated dilation and higher nitroglycerin-mediated dilation at multiple time-points. When analyzed as continuous variables, 24-h mean arterial pressure variability was inversely associated with CD62+ EMPs; visit-to-visit DBP variability was inversely associated with flow-mediated dilation normalized by smooth muscle function and was positively associated with nitroglycerin-mediated dilation; and 24-h DBP variability was positively associated with nitroglycerin-mediated dilation. All associations were independent of age, gender, body mass index and mean BP. In conclusion, in this cohort of African Americans visit-to-visit and 24-h BP variability were associated with measures of endothelial injury, endothelial function and smooth muscle function. These results suggest that BP variability may influence the pathogenesis of CV disease, in part, through influences on vascular health.

Annular dilatation and loss of sino-tubular junction in aneurysmatic aorta: implications on leaflet quality at the time of surgery. A finite element study†

PubMed Central

Weltert, Luca; de Tullio, Marco D.; Afferrante, Luciano; Salica, Andrea; Scaffa, Raffaele; Maselli, Daniele; Verzicco, Roberto; De Paulis, Ruggero

2013-01-01

OBJECTIVES In the belief that stress is the main determinant of leaflet quality deterioration, we sought to evaluate the effect of annular and/or sino-tubular junction dilatation on leaflet stress. A finite element computer-assisted stress analysis was used to model four different anatomic conditions and analyse the consequent stress pattern on the aortic valve. METHODS Theoretical models of four aortic root configurations (normal, with dilated annulus, with loss of sino-tubular junction and with both dilatation simultaneously) were created with computer-aided design technique. The pattern of stress and strain was then analysed by means of finite elements analysis, when a uniform pressure of 100 mmHg was applied to the model. Analysis produced von Mises charts (colour-coded, computational, three-dimensional stress-pattern graphics) and bidimensional plots of compared stress on arc-linear line, which allowed direct comparison of stress in the four different conditions. RESULTS Stresses both on the free margin and on the ‘belly’ of the leaflet rose from 0.28 MPa (normal conditions) to 0.32 MPa (+14%) in case of isolated dilatation of the sino-tubular junction, while increased to 0.42 MPa (+67%) in case of isolated annular dilatation, with no substantial difference whether sino-tubular junction dilatation was present or not. CONCLUSIONS Annular dilatation is the key element determining an increased stress on aortic leaflets independently from an associated sino-tubular junction dilatation. The presence of annular dilatation associated with root aneurysm greatly decreases the chance of performing a valve sparing procedure without the need for additional manoeuvres on leaflet tissue. This information may lead to a refinement in the optimal surgical strategy. PMID:23536020

Cardiorespiratory and cardiovascular interactions in cardiomyopathy patients using joint symbolic dynamic analysis.

PubMed

Giraldo, Beatriz F; Rodriguez, Javier; Caminal, Pere; Bayes-Genis, Antonio; Voss, Andreas

2015-01-01

Cardiovascular diseases are the first cause of death in developed countries. Using electrocardiographic (ECG), blood pressure (BP) and respiratory flow signals, we obtained parameters for classifying cardiomyopathy patients. 42 patients with ischemic (ICM) and dilated (DCM) cardiomyopathies were studied. The left ventricular ejection fraction (LVEF) was used to stratify patients with low risk (LR: LVEF>35%, 14 patients) and high risk (HR: LVEF≤ 35%, 28 patients) of heart attack. RR, SBP and TTot time series were extracted from the ECG, BP and respiratory flow signals, respectively. The time series were transformed to a binary space and then analyzed using Joint Symbolic Dynamic with a word length of three, characterizing them by the probability of occurrence of the words. Extracted parameters were then reduced using correlation and statistical analysis. Principal component analysis and support vector machines methods were applied to characterize the cardiorespiratory and cardiovascular interactions in ICM and DCM cardiomyopathies, obtaining an accuracy of 85.7%.

Sphericity index and E-point-to-septal-separation (EPSS) to diagnose dilated cardiomyopathy in Doberman Pinschers.

PubMed

Holler, P J; Wess, G

2014-01-01

E-point-to-septal-separation (EPSS) and the sphericity index (SI) are echocardiographic parameters that are recommended in the ESVC-DCM guidelines. However, SI cutoff values to diagnose dilated cardiomyopathy (DCM) have never been evaluated. To establish reference ranges, calculate cutoff values, and assess the clinical value of SI and EPSS to diagnose DCM in Doberman Pinschers. One hundred seventy-nine client-owned Doberman Pinschers. Three groups were formed in this prospective longitudinal study according to established Holter and echocardiographic criteria using the Simpson method of disk (SMOD): control group (97 dogs), DCM with echocardiographic changes (75 dogs) and "last normal" group (n = 7), which included dogs that developed DCM within 1.5 years, but were still normal at this time point. In a substudy, dogs with early DCM based upon SMOD values above the reference range but still normal M-Mode measurements were selected, to evaluate if EPSS or SI were abnormal using the established cutoff values. ROC-curve analysis determined <1.65 for the SI (sensitivity 86.8%; specificity 87.6%) and >6.5 mm for EPSS (sensitivity 100%; specificity 99.0%) as optimal cutoff values to diagnose DCM. Both parameters were significantly different between the control group and the DCM group (P < 0.001), but were not abnormal in the "last normal" group. In the substudy, EPSS was abnormal in 13/13 dogs and SI in 2/13 dogs. E-point-to-septal-separation is a valuable additional parameter for the diagnosis of DCM, which can enhance diagnostic capabilities of M-Mode and which performs similar as well as SMOD. Copyright © 2013 by the American College of Veterinary Internal Medicine.

Endoluminal dilatation for embedded hemodialysis catheters: A case-control study of factors associated with embedding and clinical outcomes

PubMed Central

Talreja, Hari; Ryan, Stephen Edward; Graham, Janet; Sood, Manish M.; Hadziomerovic, Adnan; Clark, Edward

2017-01-01

Background With the increasing frequency of tunneled hemodialysis catheter use there is a parallel increase in the need for removal and/or exchange. A small but significant minority of catheters become embedded or ‘stuck’ and cannot be removed by traditional means. Management of embedded catheters involves cutting the catheter, burying the retained fragment with a subsequent increased risk of infections and thrombosis. Endoluminal dilatation may provide a potential safe and effective technique for removing embedded catheters, however, to date, there is a paucity of data. Objectives 1) To determine factors associated with catheters becoming embedded and 2) to determine outcomes associated with endoluminal dilatation Methods All patients with endoluminal dilatation for embedded catheters at our institution since Jan. 2010 were included. Patients who had an embedded catheter were matched 1:3 with patients with uncomplicated catheter removal. Baseline patient and catheter characteristics were compared. Outcomes included procedural success and procedure-related infection. Logistic regression models were used to determine factors associated with embedded catheters. Results We matched 15 cases of embedded tunneled catheters with 45 controls. Among patients with embedded catheters, there were no complications with endoluminal dilatation. Factors independently associated with embedded catheters included catheter dwell time (> 2 years) and history of central venous stenosis. Conclusion Embedded catheters can be successfully managed by endoluminal dilatation with minimal complications and factors associated with embedding include dwell times > 2 years and/or with a history of central venous stenosis. PMID:28346468

A pseudo-sound constitutive relationship for the dilatational covariances in compressible turbulence: An analytical theory

NASA Technical Reports Server (NTRS)

Ristorcelli, J. R.

1995-01-01

The mathematical consequences of a few simple scaling assumptions about the effects of compressibility are explored using a simple singular perturbation idea and the methods of statistical fluid mechanics. Representations for the pressure-dilation and dilatational dissipation covariances appearing in single-point moment closures for compressible turbulence are obtained. While the results are expressed in the context of a second-order statistical closure they provide some interesting and very clear physical metaphors for the effects of compressibility that have not been seen using more traditional linear stability methods. In the limit of homogeneous turbulence with quasi-normal large-scales the expressions derived are - in the low turbulent Mach number limit - asymptotically exact. The expressions obtained are functions of the rate of change of the turbulence energy, its correlation length scale, and the relative time scale of the cascade rate. The expressions for the dilatational covariances contain constants which have a precise and definite physical significance; they are related to various integrals of the longitudinal velocity correlation. The pressure-dilation covariance is found to be a nonequilibrium phenomena related to the time rate of change of the internal energy and the kinetic energy of the turbulence. Also of interest is the fact that the representation for the dilatational dissipation in turbulence, with or without shear, features a dependence on the Reynolds number. This article is a documentation of an analytical investigation of the implications of a pseudo-sound theory for the effects of compressibility.

ON THE LACK OF TIME DILATION SIGNATURES IN GAMMA-RAY BURST LIGHT CURVES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocevski, Daniel; Petrosian, Vahe

2013-03-10

We examine the effects of time dilation on the temporal profiles of gamma-ray burst (GRB) pulses. By using prescriptions for the shape and evolution of prompt gamma-ray spectra, we can generate a simulated population of single-pulsed GRBs at a variety of redshifts and observe how their light curves would appear to a gamma-ray detector here on Earth. We find that the observer frame duration of individual pulses does not increase with redshift as 1 + z, which one would expect from cosmological expansion. This time dilation is masked by an opposite and often stronger effect: with increasing redshift and decreasingmore » signal-to-noise ratio only the brightest portion of the light curve can be detected. The results of our simulation are consistent with the fact that the simple time dilation of GRB light curves has not materialized in either the Swift or Fermi detected GRBs with known redshift. We show that the measured durations and associated E{sub iso} estimates for GRBs detected near the instrument's detection threshold should be considered lower limits to the true values. Furthermore, we conclude that attempts at distinguishing between long and short GRBs, at even moderate redshifts, cannot be done based on a burst's temporal properties alone.« less

Integral-geometry characterization of photobiomodulation effects on retinal vessel morphology

PubMed Central

Barbosa, Marconi; Natoli, Riccardo; Valter, Kriztina; Provis, Jan; Maddess, Ted

2014-01-01

The morphological characterization of quasi-planar structures represented by gray-scale images is challenging when object identification is sub-optimal due to registration artifacts. We propose two alternative procedures that enhances object identification in the integral-geometry morphological image analysis (MIA) framework. The first variant streamlines the framework by introducing an active contours segmentation process whose time step is recycled as a multi-scale parameter. In the second variant, we used the refined object identification produced in the first variant to perform the standard MIA with exact dilation radius as multi-scale parameter. Using this enhanced MIA we quantify the extent of vaso-obliteration in oxygen-induced retinopathic vascular growth, the preventative effect (by photobiomodulation) of exposure during tissue development to near-infrared light (NIR, 670 nm), and the lack of adverse effects due to exposure to NIR light. PMID:25071966

Image compression using quad-tree coding with morphological dilation

NASA Astrophysics Data System (ADS)

Wu, Jiaji; Jiang, Weiwei; Jiao, Licheng; Wang, Lei

2007-11-01

In this paper, we propose a new algorithm which integrates morphological dilation operation to quad-tree coding, the purpose of doing this is to compensate each other's drawback by using quad-tree coding and morphological dilation operation respectively. New algorithm can not only quickly find the seed significant coefficient of dilation but also break the limit of block boundary of quad-tree coding. We also make a full use of both within-subband and cross-subband correlation to avoid the expensive cost of representing insignificant coefficients. Experimental results show that our algorithm outperforms SPECK and SPIHT. Without using any arithmetic coding, our algorithm can achieve good performance with low computational cost and it's more suitable to mobile devices or scenarios with a strict real-time requirement.

Risk of recurrent or refractory strictures and outcome of endoscopic dilation for radiation-induced esophageal strictures.

PubMed

Agarwalla, Anant; Small, Aaron J; Mendelson, Aaron H; Scott, Frank I; Kochman, Michael L

2015-07-01

Radiation therapy for head, neck, and esophageal cancer can result in esophageal strictures that may be difficult to manage. Radiation-induced esophageal strictures often require repeat dilation to obtain relief of dysphagia. This study aimed to determine the long-term clinical success and rates of recurrent and refractory stenosis in patients with radiation-induced strictures undergoing dilation. Retrospective cohort study of patients with radiation-induced strictures who underwent endoscopic dilation by a single provider from October 2007-October 2012. Outcomes measured included long-term clinical efficacy, interval between sessions, number of dilations, and proportion of radiation strictures that were recurrent or refractory. Risk factors for refractory strictures were assessed. 63 patients underwent 303 dilations. All presented with a stricture >30 days after last radiation session. Clinical success to target diameter was achieved in 52 patients (83%). A mean of 3.3 (±2.6) dilations over a median period of 4 weeks was needed to achieve initial patency. Recurrence occurred in 17 (33%) at a median of 22 weeks. Twenty-seven strictures (43%) were refractory to dilation therapy. Fluoroscopy during dilation (OR 22.88; 95% CI 3.19-164.07), severe esophageal stenosis (lumen <9 mm) (OR 10.51; 95% CI 1.94-56.88), and proximal location with prior malignancy extrinsic to the lumen (OR 6.96; 95% CI 1.33-36.29) were independent predictors of refractory strictures in multivariate analysis. (1) Radiation-induced strictures have a delayed onset (>30 days) from time of radiation injury. (2) Endoscopic dilation can achieve medium-term luminal remediation but the strictures have a high long-term recurrence rate of up to 33%. (3) Remediation of radiation strictures following laryngectomy can be achieved but require frequent dilations. (4) Clinical and procedural predictors may identify patients at high risk of refractory strictures. (5) The optimal strategy in highly selected refractory patients is not clear.

Risk of Recurrent or Refractory Strictures and Outcome of Endoscopic Dilation for Radiation-Induced Esophageal Strictures

PubMed Central

Agarwalla, Anant; Small, Aaron J.; Mendelson, Aaron H.; Scott, Frank I.; Kochman, Michael L.

2014-01-01

Background Radiation therapy for head, neck, and esophageal cancer can result in esophageal strictures that may be difficult to manage. Radiation-induced esophageal strictures often require repeat dilation to obtain relief of dysphagia. This study aimed to determine the long-term clinical success and rates of recurrent and refractory stenosis in patients with radiation-induced strictures undergoing dilation. Methods Retrospective cohort study of patients with radiation-induced strictures who underwent endoscopic dilation by a single provider from October 2007– October 2012. Outcomes measured included long-term clinical efficacy, interval between sessions, number of dilations, and proportion of radiation strictures that were recurrent or refractory. Risk factors for refractory strictures were assessed. Results 63 patients underwent 303 dilations. All presented with a stricture > 30 days after last radiation session. Clinical success to target diameter was achieved in 52 patients (83%). A mean of 3.3 (+/− 2.6) dilations over a median period of 4 weeks was needed to achieve initial patency. Recurrence occurred in 17 (33%) at a median of 22 weeks. Twenty-seven strictures (43%) were refractory to dilation therapy. Fluoroscopy during dilation (OR, 22.88; 95% CI, 3.19 – 164.07), severe esophageal stenosis (lumen <9 mm) (OR, 10.51; 95% CI, 1.94 – 56.88), and proximal location with prior malignancy extrinsic to the lumen (OR, 6.96; 95% CI, 1.33 – 36.29) were independent predictors of refractory strictures in multivariate analysis. Conclusions 1. Radiation-induced strictures have a delayed onset (>30 days) from time of radiation injury. 2. Endoscopic dilation can achieve medium-term luminal remediation but the strictures have a high long-term recurrence rate of up to 33%. 3. Remediation of radiation strictures following laryngectomy can be achieved but require frequent dilations. 4. Clinical and procedural predictors may identify patients at high risk of refractory strictures. 5. The optimal strategy in highly selected refractory patients is not clear. PMID:25277484

Canine dilated cardiomyopathy: a retrospective study of signalment, presentation and clinical findings in 369 cases.

PubMed

Martin, M W S; Stafford Johnson, M J; Celona, B

2009-01-01

To review the clinical and diagnostic findings and survival of dilated cardiomyopathy from a large population of dogs in England. A retrospective study of the case records of dogs with dilated cardiomyopathy collected between January 1993 and May 2006. There were 369 dogs with dilated cardiomyopathy of which all were pure-bred dogs except for four. The most commonly affected breeds were dobermanns and boxers. Over 95 per cent of dogs weighed more than 15 kg and 73 per cent were male. The median duration of signs before referral was three weeks with 65 per cent presenting in stage 3 heart failure. The most common signs were breathlessness (67 per cent) and coughing (64 per cent). The majority of dogs (89 per cent) had an arrhythmia at presentation and 74 per cent of dogs had radiographic signs of pulmonary oedema or pleural effusion. The median survival time was 19 weeks. Dilated cardiomyopathy occurs primarily in medium to large breed pure-bred dogs, and males are more frequently affected than females. The duration of clinical signs before referral is often short and the survival times are poor. Greater awareness of affected breeds, clinical signs and diagnostic findings may help in early recognition of this disease which often has a short clinical phase.

Physical training improves flow-mediated dilation in patients with the polymetabolic syndrome.

PubMed

Lavrencic, A; Salobir, B G; Keber, I

2000-02-01

Endothelial dysfunction that can be detected as impaired flow-mediated dilation by ultrasonography is an early event in atherogenesis and has been demonstrated in healthy subjects with risk factors for atherosclerosis many years before the appearance of atheromatous plaques. We examined the influence of physical training on flow-mediated dilation in patients with the polymetabolic syndrome. Twenty-nine asymptomatic men aged 40 to 60 years with the polymetabolic syndrome were randomly divided between the control group and the training group, which trained 3 times a week for 12 weeks. On high-resolution ultrasound images, the diameter of the brachial artery was measured at rest, after reactive hyperemia (causing flow-mediated, endothelium-dependent dilation), and after sublingual glyceryltrinitrate (causing endothelium-independent vasodilation) in all subjects before and after the training period. The training program induced an increase of 18% in physical fitness. Flow-mediated dilation increased from 5.3+/-2.8% to 7.3+/-2.7% (P<0. 05). There was no change in body mass index, blood pressure, insulin resistance, lipids, and big endothelin-1 in either group. Flow-mediated dilation measured before training was negatively correlated with resting heart rate, waist-to-hip ratio, and insulin resistance. Resting heart rate emerged as the only independent determinant, which explained 22% of the variation in flow-mediated dilation. In conclusion, our findings suggest that a 3-month physical training program, which improved maximal exercise capacity, enhances flow-mediated dilation in patients with the polymetabolic syndrome.

Refining paracervical block techniques for pain control in first trimester surgical abortion: a randomized controlled noninferiority trial.

PubMed

Renner, Regina-Maria; Edelman, Alison B; Nichols, Mark D; Jensen, Jeffrey T; Lim, Jeong Y; Bednarek, Paula H

2016-11-01

Our objective was to evaluate two different aspects of the paracervical block (PCB) technique for first trimester surgical abortion, to compare a 3-min wait prior to cervical dilation to no wait and to compare four-site with two-site injection. We conducted two consecutive randomized, single-blinded noninferiority trials. In the first trial, women <11 weeks gestational age received a 20-mL 1% buffered lidocaine four-site PCB with either a 3-min wait between PCB injection and dilation or no wait. In the second trial, we compared a four-site with a two-site PCB. We evaluated dilation pain [100-mm visual analogue scale (VAS)] as the primary outcome. Secondary outcomes included pain at additional time points, anxiety, satisfaction and adverse events. Both trials fully enrolled (total n=332). Results were inconclusive as to whether no wait was noninferior to waiting 3-min prior to cervical dilation for dilation pain [VAS: 63 mm (SD, 24 mm) vs. 56 mm (SD, 32mm)] and as to whether a two-site PCB was noninferior to a four-site block [VAS: 68 mm (SD, 21 mm) vs. 60 mm (SD, 30 mm)]. Noninferiority analysis was inconclusive because the confidence interval of the mean pain score difference between groups included the predefined inferiority margin of 13-mm pain difference. Superiority analysis showed the four-site PCB to be superior to the two-site PCB. It remained inconclusive whether a 3-min wait time between PCB and cervical dilation provides noninferior pain control for first trimester surgical abortion. However, a four-site PCB appeared to be superior to a two-site PCB. It remained inconclusive whether a 3-min wait time between PCB and cervical dilation or using a two-site instead of a four-site PCB provided noninferior pain control for first trimester surgical abortion. This study did not assess whether the combination of the two separate factors provides additive benefit. Copyright © 2016 Elsevier Inc. All rights reserved.

The assessment of labor: a brief history.

PubMed

Cohen, Wayne R; Friedman, Emanuel A

2018-01-26

In the 1930s, investigators in the US, Germany and Switzerland made the first attempts to quantify the course of labor in a clinically meaningful way. They emphasized the rupture of membranes as a pivotal event governing labor progress. Attention was also placed on the total number of contractions as a guide to normality. Beginning in the 1950s, Friedman determined that changes in cervical dilatation and fetal station over time were the most useful parameters for the assessment of labor progress. He showed all normal labors had similar patterns of dilatation and descent, differing only in the durations and slopes of their component parts. These observations led to the formulation of criteria that elevated the assessment of labor from a rather arbitrary exercise to one guided by scientific objectivity. Researchers worldwide confirmed the basic nature of labor curves and validated their functionality. This system allows us to quantify the effects of parity, analgesia, maternal obesity, prior cesarean, maternal age, and fetal presentation and position on labor. It permits analysis of outcomes associated with labor aberrations, quantifies the effectiveness of treatments and assesses the need for cesarean delivery. Also, dysfunctional labor patterns serve as indicators of short- and long-term risks to offspring. We still lack the necessary translational research to link the physiologic manifestations of uterine contractility with changes in dilatation and descent. Recent efforts to interpret electrohysterographic patterns hold promise in this regard, as does preliminary exploration into the molecular basis of dysfunctional labor. For now, the clinician is best served by a system of labor assessment proposed more than 60 years ago and embellished upon in considerable detail since.

An Analytical Model for Two-Order Asperity Degradation of Rock Joints Under Constant Normal Stiffness Conditions

NASA Astrophysics Data System (ADS)

Li, Yingchun; Wu, Wei; Li, Bo

2018-05-01

Jointed rock masses during underground excavation are commonly located under the constant normal stiffness (CNS) condition. This paper presents an analytical formulation to predict the shear behaviour of rough rock joints under the CNS condition. The dilatancy and deterioration of two-order asperities are quantified by considering the variation of normal stress. We separately consider the dilation angles of waviness and unevenness, which decrease to zero as the normal stress approaches the transitional stress. The sinusoidal function naturally yields the decay of dilation angle as a function of relative normal stress. We assume that the magnitude of transitional stress is proportionate to the square root of asperity geometric area. The comparison between the analytical prediction and experimental data shows the reliability of the analytical model. All the parameters involved in the analytical model possess explicit physical meanings and are measurable from laboratory tests. The proposed model is potentially practicable for assessing the stability of underground structures at various field scales.

Slow slip generated by dehydration reaction coupled with slip-induced dilatancy and thermal pressurization

NASA Astrophysics Data System (ADS)

Yamashita, Teruo; Schubnel, Alexandre

2016-10-01

Sustained slow slip, which is a distinctive feature of slow slip events (SSEs), is investigated theoretically, assuming a fault embedded within a fluid-saturated 1D thermo-poro-elastic medium. The object of study is specifically SSEs occurring at the down-dip edge of seismogenic zone in hot subduction zones, where mineral dehydrations (antigorite, lawsonite, chlorite, and glaucophane) are expected to occur near locations where deep slow slip events are observed. In the modeling, we introduce dehydration reactions, coupled with slip-induced dilatancy and thermal pressurization, and slip evolution is assumed to interact with fluid pressure change through Coulomb's frictional stress. Our calculations show that sustained slow slip events occur when the dehydration reaction is coupled with slip-induced dilatancy. Specifically, slow slip is favored by a low initial stress drop, an initial temperature of the medium close to that of the dehydration reaction equilibrium temperature, a low permeability, and overall negative volume change associated with the reaction (i.e., void space created by the reaction larger than the space occupied by the fluid released). Importantly, if we do not assume slip-induced dilatancy, slip is accelerated with time soon after the slip onset even if the dehydration reaction is assumed. This suggests that slow slip is sustained for a long time at hot subduction zones because dehydration reaction is coupled with slip-induced dilatancy. Such slip-induced dilatancy may occur at the down-dip edge of seismogenic zone at hot subduction zones because of repetitive occurrence of dehydration reaction there.

Probabilities of Dilating Vesicoureteral Reflux in Children with First Time Simple Febrile Urinary Tract Infection, and Normal Renal and Bladder Ultrasound.

PubMed

Rianthavorn, Pornpimol; Tangngamsakul, Onjira

2016-11-01

We evaluated risk factors and assessed predicted probabilities for grade III or higher vesicoureteral reflux (dilating reflux) in children with a first simple febrile urinary tract infection and normal renal and bladder ultrasound. Data for 167 children 2 to 72 months old with a first febrile urinary tract infection and normal ultrasound were compared between those who had dilating vesicoureteral reflux (12 patients, 7.2%) and those who did not. Exclusion criteria consisted of history of prenatal hydronephrosis or familial reflux and complicated urinary tract infection. The logistic regression model was used to identify independent variables associated with dilating reflux. Predicted probabilities for dilating reflux were assessed. Patient age and prevalence of nonEscherichia coli bacteria were greater in children who had dilating reflux compared to those who did not (p = 0.02 and p = 0.004, respectively). Gender distribution was similar between the 2 groups (p = 0.08). In multivariate analysis older age and nonE. coli bacteria independently predicted dilating reflux, with odds ratios of 1.04 (95% CI 1.01-1.07, p = 0.02) and 3.76 (95% CI 1.05-13.39, p = 0.04), respectively. The impact of nonE. coli bacteria on predicted probabilities of dilating reflux increased with patient age. We support the concept of selective voiding cystourethrogram in children with a first simple febrile urinary tract infection and normal ultrasound. Voiding cystourethrogram should be considered in children with late onset urinary tract infection due to nonE. coli bacteria since they are at risk for dilating reflux even if the ultrasound is normal. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Dilation of fusion pores by crowding of SNARE proteins

PubMed Central

Wu, Zhenyong; Bello, Oscar D; Thiyagarajan, Sathish; Auclair, Sarah Marie; Vennekate, Wensi; Krishnakumar, Shyam S; O'Shaughnessy, Ben; Karatekin, Erdem

2017-01-01

Hormones and neurotransmitters are released through fluctuating exocytotic fusion pores that can flicker open and shut multiple times. Cargo release and vesicle recycling depend on the fate of the pore, which may reseal or dilate irreversibly. Pore nucleation requires zippering between vesicle-associated v-SNAREs and target membrane t-SNAREs, but the mechanisms governing the subsequent pore dilation are not understood. Here, we probed the dilation of single fusion pores using v-SNARE-reconstituted ~23-nm-diameter discoidal nanolipoprotein particles (vNLPs) as fusion partners with cells ectopically expressing cognate, 'flipped' t-SNAREs. Pore nucleation required a minimum of two v-SNAREs per NLP face, and further increases in v-SNARE copy numbers did not affect nucleation rate. By contrast, the probability of pore dilation increased with increasing v-SNARE copies and was far from saturating at 15 v-SNARE copies per face, the NLP capacity. Our experimental and computational results suggest that SNARE availability may be pivotal in determining whether neurotransmitters or hormones are released through a transient ('kiss and run') or an irreversibly dilating pore (full fusion). DOI: http://dx.doi.org/10.7554/eLife.22964.001 PMID:28346138

Impact of specific training and competition on myocardial structure and function in different age ranges of male handball players.

PubMed

Agrebi, Brahim; Tkatchuk, Vladimir; Hlila, Nawel; Mouelhi, Emna; Belhani, Ali

2015-01-01

Handball activity involves cardiac changes and demands a mixture of both eccentric and concentric remodeling within the heart. This study seeks to explore heart performance and cardiac remodeling likely to define cardiac parameters which influence specific performance in male handball players across different age ranges. Forty three players, with a regular training and competitive background in handball separated into three groups aged on average 11.78 ± 0.41 for youth players aka "schools", "elite juniors" 15.99 ± 0.81 and "elite adults" 24.46 ± 2.63 years, underwent echocardiography and ECG examinations. Incremental ergocycle and specific field (SFT) tests have also been conducted. With age and regular training and competition, myocardial remodeling in different age ranges exhibit significant differences in dilatation's parameters between "schools" and "juniors" players, such as the end-diastolic diameter (LVEDD) and the end-systolic diameter of the left ventricle (LVESD), the root of aorta (Ao) and left atrial (LA), while significant increase is observed between "juniors" and "adults" players in the interventricular septum (IVS), the posterior wall thicknesses (PWT) and LV mass index. ECG changes are also noted but NS differences were observed in studied parameters. For incremental maximal test, players demonstrate a significant increase in duration and total work between "schools" and "juniors" and, in total work only, between "juniors" and "seniors". The SFT shows improvement in performance which ranged between 26.17 ± 1.83 sec to 31.23 ± 2.34 sec respectively from "seniors" to "schools". The cross-sectional approach used to compare groups with prior hypothesis that there would be differences in exercise performance and cardiac parameters depending on duration of prior handball practice, leads to point out the early cardiac remodeling within the heart as adaptive change. Prevalence of cardiac chamber dilation with less hypertrophy remodeling was found from "schools" to "juniors" while a prevalence of cardiac hypertrophy with less pronounced chamber dilation remodeling was noted later.

Simplified Least Squares Shadowing sensitivity analysis for chaotic ODEs and PDEs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chater, Mario, E-mail: chaterm@mit.edu; Ni, Angxiu, E-mail: niangxiu@mit.edu; Wang, Qiqi, E-mail: qiqi@mit.edu

This paper develops a variant of the Least Squares Shadowing (LSS) method, which has successfully computed the derivative for several chaotic ODEs and PDEs. The development in this paper aims to simplify Least Squares Shadowing method by improving how time dilation is treated. Instead of adding an explicit time dilation term as in the original method, the new variant uses windowing, which can be more efficient and simpler to implement, especially for PDEs.

Cervical dilatation thresholds for initiation of group B streptococcus antibiotic prophylaxis for women with spontaneous preterm labor.

PubMed

Fischer, Richard L; Parikh, Laura; Hansen, Clare; Hunter, Krystal M

2015-11-01

To determine the optimal time for initiating group B streptococcus (GBS) antibiotic prophylaxis for women in spontaneous preterm labor. In total, 227 women delivering singleton infants after presenting with spontaneous preterm labor and intact membranes at 24 0/7-36 6/7 weeks were evaluated, as well as 150 undelivered women with threatened preterm labor during the same time period. The date and time of each cervical examination throughout labor were recorded. We calculated the percentages who would have correctly received at least 4 h of GBS prophylaxis if antibiotics were routinely initiated for various cervical dilatation thresholds during labor, as well as the percentage of undelivered women who would have received unnecessary antibiotic exposure at each cervical dilatation cutoff. Delaying antibiotics until cervical dilatation reached 2 cm or greater would have resulted in 62.1% receiving four or more hours of antibiotics, compared to 66.5% if antibiotics were started on all women at admission (p = 0.33), while significantly reducing unnecessary antibiotic exposure in undelivered women from 100% to 62.0% (p < 0.001). The 2-cm threshold was applicable regardless of gestational age period or prior vaginal delivery ≥ 20 weeks. GBS antibiotic prophylaxis may reasonably be withheld for women with suspected preterm labor until the cervix reaches 2 cm or greater at any time during labor.

Investigations on the hierarchy of reference frames in geodesy and geodynamics

NASA Technical Reports Server (NTRS)

Grafarend, E. W.; Mueller, I. I.; Papo, H. B.; Richter, B.

1979-01-01

Problems related to reference directions were investigated. Space and time variant angular parameters are illustrated in hierarchic structures or towers. Using least squares techniques, model towers of triads are presented which allow the formation of linear observation equations. Translational and rotational degrees of freedom (origin and orientation) are discussed along with and the notion of length and scale degrees of freedom. According to the notion of scale parallelism, scale factors with respect to a unit length are given. Three-dimensional geodesy was constructed from the set of three base vectors (gravity, earth-rotation and the ecliptic normal vector). Space and time variations are given with respect to a polar and singular value decomposition or in terms of changes in translation, rotation, deformation (shear, dilatation or angular and scale distortions).

[Pneumatic dilation in the treatment of achalasia].

PubMed

Ruiz Cuesta, Patricia; Hervás Molina, Antonio José; Jurado García, Juan; Pleguezuelo Navarro, María; García Sánchez, Valle; Casáis Juanena, Luis L; Gálvez Calderón, Carmen; Naranjo Rodríguez, Antonio

2013-10-01

Pneumatic dilation and surgical myotomy are currently the procedures of choice to treat achalasia. The selection of one or other treatment depends on the experience of each center and patient preferences. To review the experience of pneumatic dilation in patients with achalasia in our center. We included all patients with a clinical, endoscopic and manometric diagnosis compatible with achalasia who underwent pneumatic dilation in a 19-year period. All dilations were routinely performed with a Rigiflex(®) balloon, usually at pressures of 250, 250 and 300mm Hg in three inflations of one minute, each separated by one minute. The success of the dilation was assessed on the basis of the patient's symptoms, the number of sessions, the need for surgery, and the presence of complications. A total of 171 patients were included, 53.2% men and 46.8% women, with a mean age of 51.53±17.78 years (16-87 years), from June 1993 to October 2012. A 35-mm balloon was used in 157 patients, a 30-mm balloon in 9 patients and a 40-mm balloon in 7 patients. A single dilation session was required in 108 patients, two sessions were required in 56 patients, with a mean time between the first and second sessions of 25.23±43.25 months (1-215 months), and 3 sessions were required in 7 patients with a mean time between the second and third sessions of 6.86±5.33 months (1-15 months). Outcome after dilation was successful in 81% of the patients. Of the 140 responders, 121 had complete response (complete disappearance of symptoms without recurrence) and 19 partial response (initial disappearance of symptoms with subsequent reappearance). Surgery (Heller myotomy) was required in 15.8% of the patients. Perforation occurred in 4 of the 171 patients as a complication of the technique; these perforations were satisfactorily resolved, two by conservative treatment and two by surgery. There was no mortality associated with the technique or its complications. In our series, pneumatic dilation had a high success rate. In most patients, a single session was required and the complications rate was low. These results show that this technique is safe and effective in these patients, avoiding a large number of surgical interventions. Copyright © 2013 Elsevier España, S.L. and AEEH y AEG. All rights reserved.

Constraints on Friction, Dilatancy, Diffusivity, and Effective Stress From Low-Frequency Earthquake Rates on the Deep San Andreas Fault

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David

2018-01-01

Families of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor on the San Andreas Fault in central California are sensitive to tidal stresses. LFEs occur at all levels of the tides, are strongly correlated and in phase with the 200 Pa shear stresses, and weakly and not systematically correlated with the 2 kPa tidal normal stresses. We assume that LFEs are small sources that repeatedly fail during shear within a much larger scale, aseismically slipping fault zone and consider two different models of the fault slip: (1) modulation of the fault slip rate by the tidal stresses or (2) episodic slip, triggered by the tides. LFEs are strongly clustered with duration much shorter than the semidiurnal tide; they cannot be significantly modulated on that time scale. The recurrence times of clusters, however, are many times longer than the semidiurnal, leading to an appearance of tidal triggering. In this context we examine the predictions of laboratory-observed triggered frictional (dilatant) fault slip. The undrained end-member model produces no sensitivity to the tidal normal stress, and slip onsets are in phase with the tidal shear stress. The tidal correlation constrains the diffusivity to be less than 1 × 10-6/s and the product of the friction and dilatancy coefficients to be at most 5 × 10-7, orders of magnitude smaller than observed at room temperature. In the absence of dilatancy the effective normal stress at failure would be about 55 kPa. For this model the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid.

Electrocautery vs non-electrocautery dilation catheters in endoscopic ultrasonography-guided pancreatic fluid collection drainage

PubMed Central

Kitamura, Katsuya; Yamamiya, Akira; Ishii, Yu; Nomoto, Tomohiro; Honma, Tadashi; Yoshida, Hitoshi

2016-01-01

AIM: To investigate the safety and utility of an electrocautery dilation catheter for endoscopic ultrasonography (EUS)-guided pancreatic fluid collection drainage. METHODS: A single-center, exploratory, retrospective study was conducted between August 2010 and August 2014. This study was approved by the Medical Ethics Committee of our institution. Informed, written consent was obtained from each patient prior to the procedure. The subjects included 28 consecutive patients who underwent EUS-guided transmural drainage (EUS-TD) for symptomatic pancreatic and peripancreatic fluid collections (PFCs) by fine needle aspiration using a 19-gauge needle. These patients were retrospectively divided into two groups based on the use of an electrocautery dilation catheter as a fistula dilation device; 15 patients were treated with an electrocautery dilation catheter (electrocautery group), and 13 patients were treated with a non-electrocautery dilation catheter (non-electrocautery group). We evaluated the technical and clinical successes and the adverse events associated with EUS-TD for the treatment of PFCs between the two groups. RESULTS: There were no significant differences in age, sex, type, location and diameter of PFCs between the groups. Thirteen patients (87%) in the electrocautery group and 10 patients (77%) in the non-electrocautery group presented with infected PFCs. The technical success rates of EUS-TD for the treatment of PFCs were 100% (15/15) and 100% (13/13) for the electrocautery and the non-electrocautery groups, respectively. The clinical success rates of EUS-TD for the treatment of PFCs were 67% (10/15) and 69% (9/13) for the electrocautery and the non-electrocautery groups, respectively (P = 0.794). The procedure time of EUS-TD for the treatment of PFCs in the electrocautery group was significantly shorter than that of the non-electrocautery group (mean ± SD: 30 ± 12 min vs 52 ± 20 min, P < 0.001). Adverse events associated with EUS-TD for the treatment of PFCs occurred in 0 patients and 1 patient for the electrocautery and the non-electrocautery groups, respectively (P = 0.942). CONCLUSION: EUS-TD using an electrocautery dilation catheter as a fistula dilation device for the treatment of symptomatic PFCs appears safe and contributes to a shorter procedure time. PMID:27433292

Primary obstructive megaureter: the role of high pressure balloon dilation.

PubMed

Romero, Rosa M; Angulo, Jose Maria; Parente, Alberto; Rivas, Susana; Tardáguila, Ana Rosa

2014-05-01

There is a growing interest in minimally invasive treatment of primary obstructive megaureter (POM) in children. The absence of long-term follow-up data, however, makes it difficult to establish the indication for an endoscopic approach. The aim of our study is to determine the long-term efficacy of endourologic high-pressure balloon dilation of the vesicoureteral junction (VUJ) in children with POM that necessitates surgical treatment. We retrospectively reviewed the clinical records from children with POM who were treated with endourologic high-pressure balloon dilation of the VUJ from March 2003 to April 2010. To determine the long-term, a cohort study was conducted in November 2011. Endourologic dilation of the VUJ was performed with a semicompliant high-pressure balloon (2.7 FG) with a minimum balloon size of 3 mm, followed by placement of a Double-J stent. We have treated 29 (32 renal units, left [n=16], right [n=10] and bilateral [n=3]) children with a diagnosis of POM within this period. The median age at the time of the endourologic treatment was 4.04 months (range 1.6-39 months). In three cases, an open ureteral reimplantation was needed, in two cases because of intraoperative technical failure and postoperative Double-J stent migration in one patient. The 26 children (29 renal units) who had a successful endourologic dilation of the VUJ were followed with ultrasonography and MAG-3-Lasix (furosemide) studies that showed a progressive improvement of both the ureterohydronephrosis and drainage in the first 18 months in 20 patients (23 renal units) (69%). In two patients who were treated with a 3 mm balloon, a further dilation was needed, with an excellent outcome. The cohort study (at a median follow-up of 47 months) showed that in all patients who had a good outcome at the 18-month follow-up after endourologic balloon dilation remained asymptomatic with resolution of ureterohydronephrosis on the US and good drainage on the renogram, in the children with some persistent hydronephrosis. Our study shows that children with POM who were treated with high-pressure ballon dilation of the VUJ who have satisfactory appearance at 18 months maintain these results over time.

Cardiomyopathy in Boxer dogs: a retrospective study of the clinical presentation, diagnostic findings and survival.

PubMed

Palermo, Valentina; Stafford Johnson, Michael J; Sala, Elisabetta; Brambilla, Paola G; Martin, Mike W S

2011-03-01

To retrospectively compare and contrast the clinical presentation, diagnostic findings and survival in Boxer dogs with cardiomyopathy, with or without left ventricular (LV) systolic failure. Medical records of Boxers referred between 1993 and 2008 in which a diagnosis of ventricular arrhythmias and/or cardiomyopathy was made, were reviewed. Dogs were divided into two groups according to their left ventricular (LV) systolic diameter, group A normal (20 dogs) or group B dilated (59 dogs). Dogs in group A had a better outcome than dogs in group B (median survival time of 124 and 17 weeks respectively, p < 0.001). In group B, dogs with a history of collapse had a worse outcome (median survival time of 10 weeks) compared with dogs not showing collapse (median survival time 24 weeks) (p = 0.031). The majority of dogs, in this UK study, presented with the myocardial dysfunction form of the disease, with LV dilation and congestive heart failure signs. The prognosis was worse in dogs with LV dilation compared to dogs with a normal LV and ventricular arrhythmias. In the Boxers with LV dilation, dogs with collapse had a worse prognosis than those without. Copyright © 2011 Elsevier B.V. All rights reserved.

Canine gastric dilatation/volvulus syndrome in a veterinary critical care unit: 295 cases (1986-1992).

PubMed

Brockman, D J; Washabau, R J; Drobatz, K J

1995-08-15

Two hundred ninety-five case records were included in an analysis of dogs treated by a standardized protocol for gastric dilatation/volvulus syndrome between 1986 and 1992. A breed predisposition was demonstrated for Great Danes, German Shepherd Dogs, large mixed-breed dogs, and Standard Poodles. One hundred and ninety-three dogs had gastric dilatation and volvulus (GDV) confirmed at surgery, 66 had simple gastric dilatation (GD), and 36 others had gastric dilatation but volvulus could not be proved or disproved (GD +/- V). Among dogs with GDV, the fatality rate was 15% (29/193). Twenty-six (13.5%) dogs with GDV underwent partial gastrectomy, and 8 (31%) died or were subsequently euthanatized. In comparing the group of dogs with GDV that survived to those that died, there were no statistical differences in the age of dog, time between onset of clinical signs and admission, time from admission to surgery, or duration of anesthesia. Cardiac arrhythmias were detected in 40% (78/193) of the dogs with GDV. There also was no statistical correlation between development of a cardiac arrhythmia and outcome in dogs with GDV. The causes of death in dogs with GDV were multiple and varied; presumed gastric necrosis was a common reason for intraoperative euthanasia (11 dogs). Among dogs with GD or GD +/- V, the fatality rate was 0.9% (1/102).

[Significance of heterogenity in endothelium-dependent vasodilatation occurrence in healthy individuals with or without coronary risk factors].

PubMed

Polovina, Marija; Potpara, Tatjana; Giga, Vojislav; Ostojić, Miodrag

2009-10-01

Brachial artery flow-mediated dilation (FMD) is extensively used for non-invasive assessment of endothelial function. Traditionally, FMD is calculated as a percent change of arterial diameter from the baseline value at an arbitrary time point after cuff deflation (usually 60 seconds). Considerable individual differences in brachial artery temporal response to hyperemic stimulus have been observed, potentially influenced by the presence of atherosclerotic risk factors (RF). The importance of such differences for the evaluation of endothelial function has not been well established. The aim of the study was to determine the time course of maximal brachial artery endothelium-dependent dilation in healthy adults with and without RF, to explore the correlation of RF with brachial artery temporal response and to evaluate the importance of individual differences in temporal response for the assessment of endothelial function. A total of 115 healthy volunteers were included in the study. Out of them, 58 had no RF (26 men, mean age 44 +/-14 years) and 57 had at least one RF (29 men, mean age 45 +/-14 years). High-resolution color Doppler vascular ultrasound was used for brachial artery imaging. To determine maximal arterial diameter after cuff deflation and the time-point of maximal vasodilation off-line sequential measurements were performed every 10 seconds from 0 to 240 seconds after cuff release. True maximal FMD value was calculated as a percent change of the true maximal diameter from the baseline, and compared with FMD value calculated assuming that every participant reached maximal dilation at 60 seconds post cuff deflation (FMD60). Correlation of different RF with brachial artery temporal response was assessed. A maximal brachial artery endothelium-dependent vasodilation occurred from 30-120 seconds after cuff release, and the mean time of endothelium-dependent dilation was 68 +/-20 seconds. Individuals without RF had faster endothelium-dependent dilation (mean time 62 +/-17 seconds), and a shorter time-span (30 to 100 seconds), than participants with RF (mean time 75 +/-21 seconds, time-span 40 to 120 seconds) (p < 0.001). Time when the maximal endothelium-dependent dilation occurred was independently associated with age, serum lipid fractions (total cholesterol, LDL and HDL cholesterol), smoking, physical activity and C-reactive protein. True maximal FMD value in the whole group (6.7 +/-3.0%) was significantly higher (p < 0.001) than FMD60 (5.2 +/-3.5%). The same results were demonstrated for individuals with RF (4.9 +/- 1.7% vs 3.1 +/- 2.3%, p < 0.001) and without RF (8.4 +/- 2.9% vs 7.2 +/- 3.2%, p < 0.05). The temporal response of endothelium-dependent dilation is influenced by the presence of coronary FR and individually heterogeneous. When calculated according to the commonly used approach, i.e. 60 seconds after cuff deflation, FMD is significantly lower than the true maximal FMD. The routinely used measurement time-points for FMD assessment may not be adequate for the detection of true peak vasodilation in individual persons. More precise evaluation of endothelial function can be achieved with sequential measurement of arterial diameter after hyperemic stimulus.

The Gachon University Ureteral Narrowing score: A comprehensive standardized system for predicting necessity of ureteral dilatation to treat proximal ureteral calculi.

PubMed

Lee, Seung Kyu; Kim, Tae Beom; Ko, Kwang-Pil; Kim, Chang Hee; Kim, Kwang Taek; Chung, Kyung Jin; Kim, Khae Hawn; Jung, Han; Yoon, Sang Jin; Oh, Jin Kyu

2016-07-01

For treating proximal ureteral calculi, treatment decision has been known still difficult to choose ureteroscopic lithotripsy (URS) or shockwave lithotripsy. The aims of our study are to identify the possible predictors for necessity of URS and to propose the Gachon University Ureteral Narrowing scoring system (GUUN score) as a helpful predictor. We evaluated 83 consecutive patients who underwent semirigid URS due to proximal ureteral calculi between April 2011 and February 2014 by a single surgeon. We reviewed patient characteristics and pre- and postoperative parameters and surgical records. We divided the patients into 2 groups (group 1, nondilation group; group 2, dilation group) according to whether or not balloon dilation was performed. A stepwise logistic regression was performed to identify the factors that predict dilatation. Receiver operating characteristic (ROC) curves were plotted and areas under the ROC curve (AUC) were calculated to GUUN score. Mean patients' age and their stone size were 48.53±12.90 years and 7.79±2.57 cm, respectively. Significantly smaller stone size (p=0.009), lower stone density (p=0.005), and lower ureteral density differences between ureteral narrowing level and far distal ureter (UD) (p<0.001) were observed in group 1 (n=34) than in group 2 (n=49). GUUN score consists of age, stone size and UD (AUC, 0.938). Overall stone-free clearance rate was 85.5%. We suggest that the GUUN score is an excellent scoring system to predict the necessity of ureteral dilatation for decision making whether or not to perform surgical manipulation.

Effect of a Flared Renal Stent on the Performance of Fenestrated Stent-Grafts at Rest and Exercise Conditions.

PubMed

Kandail, Harkamaljot; Hamady, Mohamad; Xu, Xiao Yun

2016-10-01

To quantify the hemodynamic impact of a flared renal stent on the performance of fenestrated stent-grafts (FSGs) by analyzing flow patterns and wall shear stress-derived parameters in flared and nonflared FSGs in different physiologic scenarios. Hypothetical models of FSGs were created with and without flaring of the proximal portion of the renal stent. Flared FSGs with different dilation angles and protrusion lengths were examined, as well as a nonplanar flared FSG to account for lumbar curvature. Laminar and pulsatile blood flow was simulated by numerically solving Navier-Stokes equations. A physiologically realistic flow rate waveform was prescribed at the inlet, while downstream vasculature was modeled using a lumped parameter 3-element windkessel model. No slip boundary conditions were imposed at the FSG walls, which were assumed to be rigid. While resting simulations were performed on all the FSGs, exercise simulations were also performed on a flared FSG to quantify the effect of flaring in different physiologic scenarios. For cycle-averaged inflow of 2.94 L/min (rest) and 4.63 L/min (exercise), 27% of blood flow was channeled into each renal branch at rest and 21% under exercise for all the flared FSGs examined. Although the renal flow waveform was not affected by flaring, flow within the flared FSGs was disturbed. This flow disturbance led to high endothelial cell activation potential (ECAP) values at the renal ostia for all the flared geometries. Reducing the dilation angle or protrusion length and exercise lowered the ECAP values for flared FSGs. Flaring of renal stents has a negligible effect on the time dependence of renal flow rate waveforms and can maintain sufficient renal perfusion at rest and exercise. Local flow patterns are, however, strongly dependent on renal flaring, which creates a local flow disturbance and may increase the thrombogenicity at the renal ostia. Smaller dilation angles, shorter protrusion lengths, and moderate lower limb exercise are likely to reduce the risk of thrombosis in flared geometries. © The Author(s) 2016.

Use of a very flexible guide wire to permit dilation of complex malignant strictures of the esophagus.

PubMed

Vargas-Tank, L; Ovalle, L; Fernández, C; Mella, B; Estay, R; del Solar, M P; Soto, J R

1995-01-01

Risk of perforation is a major impediment to the use of polyvinyl bougies in palliative dilation of cancerous strictures of the esophagus. We encountered 23 patients with complex malignant strictures in whom initial dilation with Savary-Gilliard bougies was thwarted because attempts to pass a conventional Eder-Puestow guide wire were unsuccessful. As a recourse, we probed these strictures with a very flexible guide wire of the type used to implant prostheses in the biliary tract. The purpose was to establish a passage through which a standard guide wire could then be inserted. The procedure was successful in all but 4 of the 23 patients. We conclude that in such cases the preliminary use of the very flexible guide, even though time-consuming, improves the chance of effective dilation with minimal added risk.

Barriers to Eye Care Faced by Adult Hispanics with Diabetes

ERIC Educational Resources Information Center

Griffin-Shirley, Nora; Trusty, Sharon; Kelley, Emily; Siew-Jin, Lai Keun; Macias, Eduardo P.

2004-01-01

Current diabetes vision care guidelines suggest that people receive at least an annual dilated eye examination 5 years after the diagnosis of Type I diabetes and a dilated eye examination at the time of diagnosis of Type II diabetes, and at least annually thereafter. Hispanics in the United States have a three-fold greater prevalence of diabetes…

Endoscopic Pneumatic Dilation for Esophageal Achalasia.

PubMed

Markar, Sheraz; Zaninotto, Giovanni

2018-04-01

Pneumatic dilation is a well-established treatment modality that has withstood the test of time. Prospective and randomized trials have shown that in expert hands, it provides results similar to a laparoscopic Heller myotomy with fundoplication. In addition, it should be considered the primary form of treatment in patients who experience recurrence of symptoms after a surgical myotomy.

[A treatment to serious esophageal cicatrices stenosi by metal and silica gel dilator].

PubMed

Li, J; Chen, X; Sun, C; Liu, H

1999-12-01

To find an effective method of treating the esophageal cicatricial stenosis. Six cases with esophageal cicatricial stenosis were treated by mental and silica gel dilator. The effects in all six cases were satisfactory and no any complications were finded. The method is safe, effective and of no complications, the treatment time is shorter also.

Models for discrete-time self-similar vector processes with application to network traffic

NASA Astrophysics Data System (ADS)

Lee, Seungsin; Rao, Raghuveer M.; Narasimha, Rajesh

2003-07-01

The paper defines self-similarity for vector processes by employing the discrete-time continuous-dilation operation which has successfully been used previously by the authors to define 1-D discrete-time stochastic self-similar processes. To define self-similarity of vector processes, it is required to consider the cross-correlation functions between different 1-D processes as well as the autocorrelation function of each constituent 1-D process in it. System models to synthesize self-similar vector processes are constructed based on the definition. With these systems, it is possible to generate self-similar vector processes from white noise inputs. An important aspect of the proposed models is that they can be used to synthesize various types of self-similar vector processes by choosing proper parameters. Additionally, the paper presents evidence of vector self-similarity in two-channel wireless LAN data and applies the aforementioned systems to simulate the corresponding network traffic traces.

Two Dimensions of Time could produce a New Supersymmetric Theory

NASA Astrophysics Data System (ADS)

Kriske, Richard

2014-03-01

In the collapse of a system into the eigenstate of an operator,a new type of time, call it ``information time,'' could be inferred. One could look at this time to evolve the quantum state as a type of ``mass.'' This would be a correction to the explaination to the existing Higgs mechanism. Likewise one could see the dual of this in the Dilation in ``clock time'' seen in Special Relativity. In other words we see a time Dilation in ``Information Time'' as being a delay in Acceleration which we call ``mass.'' The two types of Time are Duals to each other and are symmetric. The second dimension of time has been overlooked for this reason. Time Dilation is the dual to persistance of the collapse of a system. This Duality produces some interesting and measurable effects. One conclusion that one can draw from this ``Symmetry'' is that there is a non-commuting set of operators, and a particle that connects the two ``Perpendicular'' time axis. We know from classical Quantum Theory that Momentum and Position do not commute, and this is something like the Noncommuting Time Dimensions, in that Momentum has a time-like construction and Position has a Space like construction, it is something like x, and t, not Commuting. What is the Conserved Quantity between the two types of time, is it Energy?

A system for real-time measurement of the brachial artery diameter in B-mode ultrasound images.

PubMed

Gemignani, Vincenzo; Faita, Francesco; Ghiadoni, Lorenzo; Poggianti, Elisa; Demi, Marcello

2007-03-01

The measurement of the brachial artery diameter is frequently used in clinical studies for evaluating the flow-mediated dilation and, in conjunction with the blood pressure value, for assessing arterial stiffness. This paper presents a system for computing the brachial artery diameter in real-time by analyzing B-mode ultrasound images. The method is based on a robust edge detection algorithm which is used to automatically locate the two walls of the vessel. The measure of the diameter is obtained with subpixel precision and with a temporal resolution of 25 samples/s, so that the small dilations induced by the cardiac cycle can also be retrieved. The algorithm is implemented on a standalone video processing board which acquires the analog video signal from the ultrasound equipment. Results are shown in real-time on a graphical user interface. The system was tested both on synthetic ultrasound images and in clinical studies of flow-mediated dilation. Accuracy, robustness, and intra/inter observer variability of the method were evaluated.

Stability Evaluation of Buildings in Urban Area Using Persistent Scatterer Interfometry -Focused on Thermal Expansion Effect

NASA Astrophysics Data System (ADS)

Choi, J. H.; Kim, S. W.; Won, J. S.

2017-12-01

The objective of this study is monitoring and evaluating the stability of buildings in Seoul, Korea. This study includes both algorithm development and application to a case study. The development focuses on improving the PSI approach for discriminating various geophysical phase components and separating them from the target displacement phase. A thermal expansion is one of the key components that make it difficult for precise displacement measurement. The core idea is to optimize the thermal expansion factor using air temperature data and to model the corresponding phase by fitting the residual phase. We used TerraSAR-X SAR data acquired over two years from 2011 to 2013 in Seoul, Korea. The temperature fluctuation according to seasons is considerably high in Seoul, Korea. Other problem is the highly-developed skyscrapers in Seoul, which seriously contribute to DEM errors. To avoid a high computational burden and unstable solution of the nonlinear equation due to unknown parameters (a thermal expansion parameter as well as two conventional parameters: linear velocity and DEM errors), we separate a phase model into two main steps as follows. First, multi-baseline pairs with very short time interval in which deformation components and thermal expansion can be negligible were used to estimate DEM errors first. Second, single-baseline pairs were used to estimate two remaining parameters, linear deformation rate and thermal expansion. The thermal expansion of buildings closely correlate with the seasonal temperature fluctuation. Figure 1 shows deformation patterns of two selected buildings in Seoul. In the figures of left column (Figure 1), it is difficult to observe the true ground subsidence due to a large cyclic pattern caused by thermal dilation of the buildings. The thermal dilation often mis-leads the results into wrong conclusions. After the correction by the proposed method, true ground subsidence was able to be precisely measured as in the bottom right figure in Figure 1. The results demonstrate how the thermal expansion phase blinds the time-series measurement of ground motion and how well the proposed approach able to remove the noise phases caused by thermal expansion and DEM errors. Some of the detected displacements matched well with the pre-reported events, such as ground subsidence and sinkhole.

Estimating gravity changes caused by crustal strain: application to the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Yin, Zhi; Xu, Caijun

2017-08-01

Temporal gravimetry is an efficient tool for monitoring mass transfers, but distinguishing the contribution of each process to the measured signals is challenging. Few effective methods have been developed to estimate the changes in gravity caused by crustal strain for large-scale geophysical problems. To fill this research gap, we proposed a formula that describes a negative linear correlation between changes in gravity and crustal dilatational strain. Surface observations of gravity changes and dilatational strains were simulated using PSGRN/PSCMP, which is a numerical code used to calculate the surface response to fault dislocations, and the accuracy of the formula was quantitatively verified. Four parameters are required for this formula: the crustal dilatational strain, the crustal density, the Moho depth, and a coefficient that characterizes the degree of crust-mantle coupling. To illustrate the application of this new method to a natural case study, including specifying the values of the necessary parameters, the crustal strain-caused gravity changes (CSGCs) were calculated at 1° × 1° grid nodes over the Tibetan Plateau (TP). The CSGC model shows that most of the crust of the TP is undergoing extension, which generates negative gravity signals. The magnitude of the Tibetan CSGC model is approximately 0.2 μGal yr-1, which is similar to the results obtained from numerical modelling of the crustal tectonics of the Taiwanese Orogen. To evaluate the reliability of the Tibetan CSGC model, the uncertainties in the crustal dilatational strain, crustal density, Moho depth, and crust-mantle coupling factor were evaluated and then used to estimate the CSGC uncertainty by applying the error propagation law. The CSGC model was used to analyse the mass transfers of the TP. The results suggest that a significant mass accumulation process may be occurring beneath the crust of the northern TP.

Balloon dilation of the cartilaginous eustachian tube.

PubMed

Poe, Dennis S; Silvola, Juha; Pyykkö, Ilmari

2011-04-01

(1) To translate techniques developed in a previous cadaver study of balloon dilation of the cartilaginous eustachian tube (ET) into clinical treatment for refractory dilatory dysfunction and (2) to study the safety/efficacy of the technique in a pilot clinical trial. Prospective with subjects as their own historical controls since June 2009. Regional academic center. Eleven consecutive adult patients with longstanding otitis media with effusion (OME) who were unable to autoinsufflate their ET by Valsalva, swallow, or yawn and who had previous tympanostomies (average, 4.7). At the time of intervention, 5 of 11 had a tube; 2 of 11 had a tympanic membrane (TM) perforation. Four of 11 had intact TMs, 2 with OME and tympanogram type B and 2 with TM retraction and tympanogram types B and C. Balloon dilation of the cartilaginous ET was performed with sinus dilation instruments via transnasal endoscopic approach under general anesthesia in a day surgery setting. Inflation was to a maximum of 12 atm for 1 minute. ability to Valsalva, rating of ET mucosal inflammation, tympanogram, and otomicroscopy findings. All cases successfully dilated. Eleven of 11 could self-insufflate by Valsalva (P < .001); tympanograms were A (4/11), C (1/11), or open (6/11). All atelectases resolved. Procedures were well tolerated, without pain or complications related to dilation. Dilation of the cartilaginous ET appeared to be beneficial and without significant adverse effects in the treatment of ET dilatory dysfunction. Larger controlled trials with long-term results are now justified and needed.

GRB Diversity vs. Utility as Cosmological Probes

NASA Technical Reports Server (NTRS)

Norris, J. P.; Scargle, J. D.; Bonnell, J. T.; Nemiroff, R. J.; Young, Richard E. (Technical Monitor)

1997-01-01

Recent detections of apparent gamma-ray burst (GRB) counterparts in optical and radio wavebands strongly favor the cosmological distance scale, at least for some GRBs, opening the possibility of GRBs serving as cosmological probes. But GRBs exhibit great diversity: in total duration; in number, width and pulse configuration; and in pulse and overall spectral evolution. However, it is possible that a portion of this behavior reflects a luminosity distribution, and possible that evolution of with cosmic time introduces dispersion into the average GRB characteristics -- issues analogous to those encountered with quasars. The temporal domain offers a rich avenue to investigate this problem. When corrected for assumed spectral redshift, time dilation of event durations, pulse widths, and intervals between pulses must yield the same time-dilation factor as a function of peak flux, or else a luminosity distribution may be the cause of observed time dilation effects. We describe results of burst analysis using an automated, Bayesian-based algorithm to determine burst temporal characteristics for different peak flux groups, and derived constraints on any physical process that would introduce a luminosity distribution.

Dilation of the ascending aorta after balloon valvuloplasty for aortic stenosis during infancy and childhood.

PubMed

McElhinney, Doff B; Lacro, Ronald V; Gauvreau, Kimberlee; O'Brien, Cheryl M; Yaroglu Kazanci, Selcen; Vogel, Melanie; Emani, Sitaram; Brown, David W

2012-09-01

Dilation of the ascending aorta (AA) is common in patients with a bicuspid aortic valve. The natural history of the aortic root and AA and the risk factors for dilation have not been characterized in patients with congenital aortic stenosis (AS) treated with balloon valvuloplasty during childhood. The present study was performed to determine the prevalence of aortic dilation in patients with congenital AS before and up to 20 years after balloon valvuloplasty performed during childhood. In patients who underwent balloon valvuloplasty for AS at age ≤ 18 years from 1984 to 2005, the aortic diameter measurements before intervention and at 5-year intervals afterward were recorded and the Z scores calculated. Among 156 patients (median age 1.5 years at valvuloplasty), the AA Z scores were significantly larger than normal before intervention (median Z score 1.5) and at all follow-up points (all p <0.001). Using mixed modeling, with time as a categorical variable (before intervention, 5-year window, 10-year window, and so forth), the mean AA Z score was greater at all postvalvuloplasty points than before the intervention, with mean Z score increases of 1.20 at 5 years and 2.11 at 20 years (p <0.001). Moderate or greater aortic regurgitation early after valvuloplasty was associated with greater AA Z scores than mild or less aortic regurgitation, with a progressive difference over time. More significant residual AS after valvuloplasty was associated with lower AA Z scores over time. In conclusion, AA dilation is common in children with congenital AS and continues to progress over many years after balloon valvuloplasty. Copyright © 2012 Elsevier Inc. All rights reserved.

Surface Brightness Test and Plasma Redshift

NASA Astrophysics Data System (ADS)

Brynjolfsson, Ari

2006-03-01

The plasma redshift of photons in a hot sparse plasma follows from basic axioms of physics. It has no adjustable parameters (arXiv:astro-ph/0406437). Both the distance-redshift relation and the magnitude-redshift relation for supernovae and galaxies are well-defined functions of the average electron densities in intergalactic space. We have previously shown that the predictions of the magnitude-redshift relation in plasma- redshift cosmology match well the observed relations for the type Ia supernovae (SNe). No adjustable parameters such as the time variable ``dark energy'' and ``dark matter'' are needed. We have also shown that plasma redshift cosmology predicts well the intensity and black body spectrum of the cosmic microwave background (CMB). Plasma redshift explains also the spectrum below and above the 2.73 K black body CMB, and the X-ray background. In the following, we will show that the good observations and analyses of the relation between surface brightness and redshift for galaxies, as determined by Allan Sandage and Lori M. Lubin in 2001, are well predicted by the plasma redshift. All these relations are inconsistent with cosmic time dilation and the contemporary big-bang cosmology.

No Beneficial Effect of General and Specific Anti-Inflammatory Therapies on Aortic Dilatation in Marfan Mice

PubMed Central

den Hartog, Alexander W.; Radonic, Teodora; de Vries, Carlie J. M.; Zwinderman, Aeilko H.; Groenink, Maarten; Mulder, Barbara J. M.; de Waard, Vivian

2014-01-01

Aims Patients with Marfan syndrome have an increased risk of life-threatening aortic complications, mostly preceded by aortic dilatation. In the FBN1 C1039G/+ Marfan mouse model, losartan decreases aortic root dilatation. We recently confirmed this beneficial effect of losartan in adult patients with Marfan syndrome. The straightforward translation of this mouse model to man is reassuring to test novel treatment strategies. A number of studies have shown signs of inflammation in aortic tissue of Marfan patients. This study examined the efficacy of anti-inflammatory therapies in attenuating aortic root dilation in Marfan syndrome and compared effects to the main preventative agent, losartan. Methods and Results To inhibit inflammation in FBN1 C1039G/+ Marfan mice, we treated the mice with losartan (angiotensin II receptor type 1 inhibitor), methylprednisolone (corticosteroid) or abatacept (T-cell-specific inhibitor). Treatment was initiated in adult Marfan mice with already existing aortic root dilatation, and applied for eight weeks. Methylprednisolone- or abatacept-treated mice did not reveal a reduction in aortic root dilatation. In this short time frame, losartan was the only treatment that significantly reduced aorta inflammation, transforming growth factor-beta (TGF-β) signaling and aortic root dilatation rate in these adult Marfan mice. Moreover, the methylprednisolone-treated mice had significantly more aortic alcian blue staining as a marker for aortic damage. Conclusion Anti-inflammatory agents do not reduce the aortic dilatation rate in Marfan mice, but possibly increase aortic damage. Currently, the most promising therapeutic drug in Marfan syndrome is losartan, by blocking the angiotensin II receptor type 1 and thereby inhibiting pSmad2 signaling. PMID:25238161

Time of Occurrence and Duration of Atrial Fibrillation Following Coronary Artery Bypass Grafting.

PubMed

Avdic, Sevleta; Osmanovic, Enes; Kadric, Nedzad; Mujanovic, Emir; Ibisevic, Merima; Avdic, Azra

2016-04-01

Dilatation of the left atrium and left ventricular diastolic dysfunction (DDLV) according to recent studies has significance in the occurrence of postoperative atrial fibrillation (AF), stroke and death. Authors of some studies found no relationship between these parameters and atrial fibrillation. this study is to determine the time of occurrence and duration of atrial fibrillation in patients after surgical revascularization (CABG) due to the presence of left ventricular diastolic dysfunction and left atrium dilatation and identify the most significant predictors of incident AF. Prospective study included 116 patients undergoing surgical myocardial revascularization followed from admission to discharge. The study was conducted at the Special Hospital "Heart Center BH" Tuzla for a period of one year (March 2011/2012 g.). For all patients was performed preoperative ultrasound examination, especially parameters of diastolic function of the left ventricle and left atrium volume index (LAVi), as the best parameter sized left atrium, and the postoperative occurrence of certain AF and day occurrence, duration in hours, the number of attacks. To assess whether an event occurred or not was used logistic regression, and the effect of time on the event of interest is analyzed by Cox 's regression hazard parallel. 75.9 % of patients had DDLV, and 91.4 % were hypertensives, 12.9 % from the previous stroke (ICV) and 42.2 % diabetics (DM), 14 % with COPD. The average age of patients was 61.41 ± 4.69 years. In both groups was 32.8 % women and 67.2 % men. LAVi preoperative values were significantly higher as DDLV greater degree. In patients with DDLV and higher values LAVi risk of AF is higher, the greater the length of AF and significantly higher number of attacks FA. Early occurrence of atrial fibrillation and its longer duration in function with increasing LAVi a marked increase in the value LAVi have the greatest hazard for the early appearance of atrial fibrillation. As a result of analysis of the most significant predictors of AF are DDLV and LAVi. Postoperative atrial fibrillation occurs earlier and lasts longer in patients with DDLV and elevated left atrial volume index especially LAV > 36ml/m(2). LAVi has the best explanation of the function of hazard occurrence of atrial fibrillation after CABG.

Infertility associated with persistent hymen in an alpaca and a llama

PubMed Central

Tan, Rachel H.H.; Dascanio, John J.

2008-01-01

Perforation and dilation of the persistent hymen in an alpaca and a llama, detected by vaginal examination and endoscopy, was achieved by use of a sigmoidoscope and incremental dilation using cylindrical instruments to a maximum diameter of 38 mm. Outcome and subsequent fertility are dependent on length of time the obstruction has been present and secondary uterine disease. PMID:19183735

Percutaneous dilatational tracheostomy following total artificial heart implantation.

PubMed

Spiliopoulos, Sotirios; Dimitriou, Alexandros Merkourios; Serrano, Maria Rosario; Guersoy, Dilek; Autschbach, Ruediger; Goetzenich, Andreas; Koerfer, Reiner; Tenderich, Gero

2015-07-01

Coagulation disorders and an immune-altered state are common among total artificial heart patients. In this context, we sought to evaluate the safety of percutaneous dilatational tracheostomy in cases of prolonged need for mechanical ventilatory support. We retrospectively analysed the charts of 11 total artificial heart patients who received percutaneous dilatational tracheostomy. We focused on early and late complications. We observed no major complications and no procedure-related deaths. Early minor complications included venous oozing (45.4%) and one case of local infection. Late complications, including subglottic stenosis, stomal infection or infections of the lower respiratory tract, were not observed. In conclusion, percutaneous dilatational tracheostomy in total artificial heart patients is safe. Considering the well-known benefits of early tracheotomy over prolonged translaryngeal intubation, we advocate early timing of therapy in cases of prolonged mechanical ventilation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Regulation of landslide motion by dilatancy and pore pressure feedback

USGS Publications Warehouse

Iverson, R.M.

2005-01-01

A new mathematical model clarifies how diverse styles and rates of landslide motion can result from regulation of Coulomb friction by dilation or contraction of water-saturated basal shear zones. Normalization of the model equations shows that feedback due to coupling between landslide motion, shear zone volume change, and pore pressure change depends on a single dimensionless parameter ??, which, in turn, depends on the dilatancy angle ?? and the intrinsic timescales for pore pressure generation and dissipation. If shear zone soil contracts during slope failure, then ?? 0, and negative feedback permits slow, steady landslide motion to occur while positive pore pressure is supplied by rain infiltration. Steady state slip velocities v0 obey v0 = -(K/??) p*e, where K is the hydraulic conductivity and p*e is the normalized (dimensionless) negative pore pressure generated by dilation. If rain infiltration and attendant pore pressure growth continue unabated, however, their influence ultimately overwhelms the stabilizing influence of negative p*e. Then, unbounded landslide acceleration occurs, accentuated by an instability that develops if ?? diminishes as landslide motion proceeds. Nonetheless, numerical solutions of the model equations show that slow, nearly steady motion of a clay-rich landslide may persist for many months as a result of negative pore pressure feedback that regulates basal Coulomb friction. Similarly stabilized motion is less likely to occur in sand-rich landslides that are characterized by weaker negative feedback.

Brain natriuretic peptide is not predictive of dilated cardiomyopathy in Becker and Duchenne muscular dystrophy patients and carriers.

PubMed

Schade van Westrum, Steven; Dekker, Lukas; de Haan, Rob; Endert, Erik; Ginjaar, Ieke; de Visser, Marianne; van der Kooi, Anneke

2013-07-16

Cardiomyopathy is reported in Duchenne and Becker muscle dystrophy patients and female carriers. Brain Natriuretic peptide (BNP) is a hormone produced mainly by ventricular cardiomyocytes and its production is up regulated in reaction to increased wall stretching. N-terminal-proBNP (NT-proBNP) has been shown to be a robust laboratory parameter to diagnose and monitor cardiac failure, and it may be helpful to screen for asymptomatic left ventricular dysfunction. Therefore we tested whether NT-proBNP can distinguish patients with Duchenne or Becker muscular dystrophy patients and carriers of a dystrophin mutation with a dilated cardiomyopathy from those without. In a cohort of Duchenne and Becker muscle dystrophy patients (n = 143) and carriers (n = 219) NT-proBNP was measured, and echocardiography was performed to diagnose dilated cardiomyopathy (DCM). In total sixty-one patients (17%) fulfilled the criteria for DCM, whereas 283 patients (78%) had an elevated NT-pro BNP. The sensitivity of NT-proBNP for DCM in patients or carriers was 85%, the specificity 23%, area under the ROC-curve = 0.56. In the specified subgroups there was also no association. Measurement of NT-pro BNP in patients suffering from Duchenne or Becker muscular dystrophy and carriers does not distinguish between those with and without dilated cardiomyopathy.

Usefulness of Ultrasonography and Cortical Transit Time to Differentiate Nonobstructive From Obstructive Dilatation in the Management of Prenatally Detected Pelvic Ureteric Junction Like Obstruction.

PubMed

Sharma, Gyanendra; Sharma, Anshu

2017-12-01

To differentiate a nonobstructive dilatation from an obstructive dilatation in prenatally detected presumed pelvi-ureteric junction obstruction so that intervention can be planned before irreversible damage can occur to the renal unit. From January 2012 to December 2016, all patients with prenatally detected or asymptomatic incidentally detected presumed pelvi-ureteric junction obstruction were evaluated by ultrasonography and renogram. The anteroposterior diameter of the renal pelvis was measured in supine and prone position. Presence of calyceal dilatation in prone position was noted. They were categorized into obstructed, nonobstructed, and equivocal groups based on sonography findings. The differential renal function and the cortical transit time (CTT) was calculated and compared with the sonography groups. Of the 98 patients, 72 were in the obstructed, 18 were in the nonobstructed, and 8 were in the equivocal category. All except 1 in the nonobstructed category had a function of >40% with CTT of <3 minutes. Seventy patients in the obstructed category had a CTT of >3 minutes, whereas 61 had function <40% on initial evaluation. Eleven patients in the obstructed category with an initial function of >40% had CTT of >3 minutes. All of them showed increasing hydronephrosis and deterioration of function during follow-up, necessitating pyeloplasty. All patients in the equivocal group had function >40% and CTT <3 minutes. Ultrasonography along with CTT can help to differentiate nonobstructive from obstructive dilatation. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of inclusions on heterogeneous crack nucleation in nanocomposites

NASA Astrophysics Data System (ADS)

Gutkin, M. Yu.; Ovid'Ko, I. A.; Skiba, N. V.

2007-02-01

A two-dimensional theoretical model is proposed for the heterogeneous nucleation of a grain-boundary nanocrack in a nanocomposite consisting of a nanocrystalline matrix and nanoinclusions whose elastic moduli are identical to those of the matrix. The inclusions have the form of rods with a rectangular cross section and undergo dilatation eigenstrain induced by the differences in the lattice parameters and thermal expansion coefficients of the matrix and inclusions. In terms of the model, a mode-I-II nanocrack nucleates at the negative disclination of a biaxial dipole consisting of wedge grain-boundary (or junction) disclinations; then, the nanocrack opens along a grain boundary and reaches an inclusion boundary. Depending on the relative positions and orientations of the initial segment of the nanocrack and the inclusion, the nanocrack can either penetrate into the inclusion or bypass it along the matrix-inclusion interface. The nanocrack nucleation probability increases near an inclusion with negative (compressive) dilatation eigenstrain. A decrease in the inclusion size decreases (increases) the probability of a crack opening along the interface if the dilatation eigenstrain is negative (positive).

Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy.

PubMed

Przywara, John F; Abel, Steven B; Peacock, John T; Shott, Susan

2014-10-01

This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy.

Simulation of spatially evolving turbulence and the applicability of Taylor's hypothesis in compressible flow

NASA Technical Reports Server (NTRS)

Lee, Sangsan; Lele, Sanjiva K.; Moin, Parviz

1992-01-01

For the numerical simulation of inhomogeneous turbulent flows, a method is developed for generating stochastic inflow boundary conditions with a prescribed power spectrum. Turbulence statistics from spatial simulations using this method with a low fluctuation Mach number are in excellent agreement with the experimental data, which validates the procedure. Turbulence statistics from spatial simulations are also compared to those from temporal simulations using Taylor's hypothesis. Statistics such as turbulence intensity, vorticity, and velocity derivative skewness compare favorably with the temporal simulation. However, the statistics of dilatation show a significant departure from those obtained in the temporal simulation. To directly check the applicability of Taylor's hypothesis, space-time correlations of fluctuations in velocity, vorticity, and dilatation are investigated. Convection velocities based on vorticity and velocity fluctuations are computed as functions of the spatial and temporal separations. The profile of the space-time correlation of dilatation fluctuations is explained via a wave propagation model.

The principles and technical aspects of diuresis renography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conway, J.J.

1989-12-01

It is intuitive that dilation of the urinary tract is most likely caused by obstruction. However, the opposite is more often true. That is, dilation is not associated with obstruction, especially in children. The most common causes for hydronephrosis and hydroureter include infection, vesicoureteral reflux, congenital megacalyces and megaureter, previous obstruction, and bladder noncompliance. Theoretically, one can consider obstruction on the basis of its significance, which is that there may be a loss of renal function with time. Techniques such as intravenous pyelography and ultrasonography, which anatomically document the degree of dilation of the urinary tract, cannot quantitatively determine themore » presence of obstruction or its significance. Radionuclide renography more readily quantifies abnormal renal function. Serial renographic studies with furosemide can document renal function loss and, thus, determine the significance of the obstruction. Diuresis renography with furosemide provides an objective quantitative means for determining the renal function changes over time.« less

The pupil as an indicator of unconscious memory: Introducing the pupil priming effect.

PubMed

Gomes, Carlos Alexandre; Montaldi, Daniela; Mayes, Andrew

2015-06-01

We explored whether object behavioral priming and pupil changes occur in the absence of recognition memory. Experiment 1 found behavioral priming for unrecognized objects (Ms) regardless of whether they had been encoded perceptually or conceptually. Using the same perceptual encoding task, Experiment 2 showed greater pupil dilation for Ms than for correct rejections of unstudied objects (CRs) when reaction times were matched. In Experiment 3, there was relatively less pupil dilation for Ms than for similarly matched CRs when objects had been encoded conceptually. Mean/peak pupil dilation for CRs, but not Ms, increased in Experiment 3, in which novelty expectation was also reduced, and the pupillary time course for both Ms and CRs was distinct in the two experiments. These findings indicate that both behavioral and pupil memory occur for studied, but unrecognized stimuli, and suggest that encoding and novelty expectation modulate pupillary memory responses. © 2015 Society for Psychophysiological Research.

Laparoscopic Heller Myotomy for Non-Dilated Esophageal Achalasia in Children with Intraoperative Stepped Dilation Under Image Guidance: Attempting Complete Myotomy.

PubMed

Miyano, Go; Miyake, Hiromu; Koyama, Mariko; Morita, Keiichi; Kaneshiro, Masakatsu; Nouso, Hiroshi; Yamoto, Masaya; Fukumoto, Koji; Urushihara, Naoto

2016-05-01

This study presents a modified surgical approach to laparoscopic myotomy for achalasia using stepped dilation with a Rigiflex balloon and contrast medium under image guidance. A 10-year-old boy with persistent dysphagia and vomiting had ingested only liquids for 3 months, losing >10 kg in body weight. Barium swallow and esophageal manometry diagnosed esophageal achalasia with mild esophageal dilatation. After failed pneumatic dilatation, laparoscopic Heller myotomy with Dor fundoplication was performed. Prior to surgery, a Rigiflex balloon dilator was placed within the esophagus near the diaphragmatic hiatus. A four-port technique was used, and mobilization of the esophagus was limited to the anterior aspect. A 5-cm Heller myotomy was performed, extending another 2 cm onto the anterior gastric wall. During myotomy, the Rigiflex balloon was serially dilated from 30 to 50 mL, and filled with contrast medium under fluoroscopic image guidance in order to maintain appropriate tension on the esophagus to facilitate myotomy, and to confirm adequate myotomy with sufficient release of lower esophageal sphincter by resecting residual circular muscle fibers. Residual circular muscle fibers can be simultaneously visualized under both fluoroscopic image guidance and direct observation through the laparoscope, and they were cut precisely until the residual notch fully disappeared. Dor fundoplication was completed. The operative time was 180 minutes, and oral intake was started after esophagography on postoperative day 1. As of the 12-month follow-up, the patient has not shown any symptoms, and his postoperative course appeared satisfactory.

Anal self-massage in the treatment of acute anal fissure: a randomized prospective study.

PubMed

Gaj, Fabio; Biviano, Ivano; Candeloro, Laura; Andreuccetti, Jacopo

2017-01-01

An anal fissure (AF) is a tear in the epithelial lining of the anal canal. This is a very common condition, but the choice of treatment is unclear. The use of anal dilators is effective, economic, and safe. The aim of the study was to compare the efficacy of two conservative treatments, the use of anal dilators or a finger for anal dilatation, in reducing anal pressure and resolving anal fissures. Fifty patients with a clinical diagnosis of AF were randomly assigned to one of the treatments, self-massage of the anal sphincter (group A, 25 patients) or passive dilatation using dilators (group B, 25 patients). All patients were evaluated at baseline, at the end of treatment, and after 12 weeks and 6 months. Pain was measured using a visual analog scale. After the treatment, 60% of patients treated with dilators and 80% of patients treated with anal self-massage using a finger showed disappearance of their anal fissures. A comparison between signs and symptoms reported by the patients in the two groups showed a statistically significant reduction in anal pain (group A, P=0.0001; group B, P=0.0001) and bleeding after defecation (group A, P=0.001, group B, P=0.001). At 6 months after treatment, a significantly greater reduction in anal pain was observed in Group A compared to Group B (P=0.02). The use of anal self-massage with a finger appears to induce a better resolution of acute anal fissure than do anal dilators, and in a shorter time.

Segmental dilatation of sigmoid colon in a neonate: atypical presentation and histology.

PubMed

Mahadevaiah, Shubha Attibele; Panjwani, Poonam; Kini, Usha; Mohanty, Suravi; Das, Kanishka

2011-03-01

Segmental dilatation of the colon is a rare disorder of colonic motility in children, often presenting with severe constipation in older infants, children, and occasionally adults. It may mimic the commoner Hirschsprung disease clinicoradiologically but differs in that the ganglion cell morphology and distribution are typically normal in the colon. We report a neonate with segmental dilatation of the sigmoid colon who had an atypical clinical presentation and describe certain abnormalities in bowel histology (hypertrophied muscularis propria, nerve plexus, and ganglion cells located within the circular layer rather than the normal myenteric location), for the first time in the English literature. Copyright © 2011 Elsevier Inc. All rights reserved.

Hybrid Approach for Biliary Interventions Employing MRI-Guided Bile Duct Puncture with Near-Real-Time Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wybranski, Christian, E-mail: Christian.Wybranski@uk-koeln.de; Pech, Maciej; Lux, Anke

ObjectiveTo assess the feasibility of a hybrid approach employing MRI-guided bile duct (BD) puncture for subsequent fluoroscopy-guided biliary interventions in patients with non-dilated (≤3 mm) or dilated BD (≥3 mm) but unfavorable conditions for ultrasonography (US)-guided BD puncture.MethodsA total of 23 hybrid interventions were performed in 21 patients. Visualization of BD and puncture needles (PN) in the interventional MR images was rated on a 5-point Likert scale by two radiologists. Technical success, planning time, BD puncture time and positioning adjustments of the PN as well as technical success of the biliary intervention and complication rate were recorded.ResultsVisualization even of third-order non-dilated BDmore » and PN was rated excellent by both radiologists with good to excellent interrater agreement. MRI-guided BD puncture was successful in all cases. Planning and BD puncture times were 1:36 ± 2.13 (0:16–11:07) min. and 3:58 ± 2:35 (1:11–9:32) min. Positioning adjustments of the PN was necessary in two patients. Repeated capsular puncture was not necessary in any case. All biliary interventions were completed successfully without major complications.ConclusionA hybrid approach which employs MRI-guided BD puncture for subsequent fluoroscopy-guided biliary intervention is feasible in clinical routine and yields high technical success in patients with non-dilated BD and/or unfavorable conditions for US-guided puncture. Excellent visualization of BD and PN in near-real-time interventional MRI allows successful cannulation of the BD.« less

On the permeation of large organic cations through the pore of ATP-gated P2X receptors

PubMed Central

Harkat, Mahboubi; Peverini, Laurie; Dunning, Kate; Beudez, Juline; Martz, Adeline; Calimet, Nicolas; Specht, Alexandre; Cecchini, Marco; Chataigneau, Thierry; Grutter, Thomas

2017-01-01

Pore dilation is thought to be a hallmark of purinergic P2X receptors. The most commonly held view of this unusual process posits that under prolonged ATP exposure the ion pore expands in a striking manner from an initial small-cation conductive state to a dilated state, which allows the passage of larger synthetic cations, such as N-methyl-d-glucamine (NMDG+). However, this mechanism is controversial, and the identity of the natural large permeating cations remains elusive. Here, we provide evidence that, contrary to the time-dependent pore dilation model, ATP binding opens an NMDG+-permeable channel within milliseconds, with a conductance that remains stable over time. We show that the time course of NMDG+ permeability superimposes that of Na+ and demonstrate that the molecular motions leading to the permeation of NMDG+ are very similar to those that drive Na+ flow. We found, however, that NMDG+ “percolates” 10 times slower than Na+ in the open state, likely due to a conformational and orientational selection of permeating molecules. We further uncover that several P2X receptors, including those able to desensitize, are permeable not only to NMDG+ but also to spermidine, a large natural cation involved in ion channel modulation, revealing a previously unrecognized P2X-mediated signaling. Altogether, our data do not support a time-dependent dilation of the pore on its own but rather reveal that the open pore of P2X receptors is wide enough to allow the permeation of large organic cations, including natural ones. This permeation mechanism has considerable physiological significance. PMID:28442564

Multi-Rocket Thought Experiment

NASA Astrophysics Data System (ADS)

Smarandache, Florentin

2014-03-01

We consider n>=2 identical rockets: R1 ,R2 , ..., Rn. Each of them moving at constant different velocities respectively v1 ,v2 , ..., vn on parallel directions in the same sense. In each rocket there is a light clock, the observer on earth also has a light clock. All n + 1 light clocks are identical and synchronized. The proper time Δt' in each rocket is the same. (1) If we consider the observer on earth and the first rocket R1, then the non-proper time Δt of the observer on earth is dilated with the factor D(v1) : or Δt = Δt' D(v1) (1) But if we consider the observer on earth and the second rocket R2 , then the non-proper time Δt of the observer on earth is dilated with a different factor D(v2) : or Δt = Δt' D(v2) And so on. Therefore simultaneously Δt is dilated with different factors D(v1) , D(v2), ..., D(vn) , which is a multiple contradiction.

Picosecond imaging of inertial confinement fusion plasmas using electron pulse-dilation

NASA Astrophysics Data System (ADS)

Hilsabeck, T. J.; Nagel, S. R.; Hares, J. D.; Kilkenny, J. D.; Bell, P. M.; Bradley, D. K.; Dymoke-Bradshaw, A. K. L.; Piston, K.; Chung, T. M.

2017-02-01

Laser driven inertial confinement fusion (ICF) plasmas typically have burn durations on the order of 100 ps. Time resolved imaging of the x-ray self emission during the hot spot formation is an important diagnostic tool which gives information on implosion symmetry, transient features and stagnation time. Traditional x-ray gated imagers for ICF use microchannel plate detectors to obtain gate widths of 40-100 ps. The development of electron pulse-dilation imaging has enabled a 10X improvement in temporal resolution over legacy instruments. In this technique, the incoming x-ray image is converted to electrons at a photocathode. The electrons are accelerated with a time-varying potential that leads to temporal expansion as the electron signal transits the tube. This expanded signal is recorded with a gated detector and the effective temporal resolution of the composite system can be as low as several picoseconds. An instrument based on this principle, known as the Dilation X-ray Imager (DIXI) has been constructed and fielded at the National Ignition Facility. Design features and experimental results from DIXI will be presented.

Cervical dilation at the time of cesarean section for dystocia -- effect on subsequent trial of labor.

PubMed

Abildgaard, Helle; Ingerslev, Marie Diness; Nickelsen, Carsten; Secher, Niels Joergen

2013-02-01

To investigate the effect of cervical dilation at the time of cesarean section due to dystocia and success in a subsequent pregnancy of attempted vaginal delivery. Retrospective study. University hospital in Copenhagen capital area. All women with a prior cesarean section due to dystocia who had undergone a subsequent pregnancy with a singleton delivery during 2006-2010. Medical records were reviewed for prior vaginal birth, cervical dilation reached before cesarean section and induction of labor, gestational age, use of oxytocin, epidural anesthesia and mode of birth was collected. A total of 889 women were included; 373 had had a trial of labor. The success rate for vaginal birth among women with prior cesarean section for dystocia at 4-8 cm dilation was 39%, but 59% for women in whom prior cesarean section had been done at a fully or almost fully dilated cervix (9-10 cm) (p < 0.001). Among the women with a previous vaginal delivery prior to their cesarean section, the success rate for vaginal birth was 76.2%, in contrast to 48.9% in the group without a previous vaginal delivery (p < 0.01). Women who had a trial of labor after a prior cesarean section for dystocia done late in labor and women with a vaginal delivery prior to their cesarean section had a greater chance of a successful vaginal birth during a subsequent delivery. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

Comparison of the safety and efficacy of one-shot and telescopic metal dilatation in percutaneous nephrolithotomy: a randomized controlled trial.

PubMed

Amirhassani, Shahriar; Mousavi-Bahar, Seyed Habibollah; Iloon Kashkouli, Abdolmajid; Torabian, Saadat

2014-06-01

Minimizing X-ray exposure during percutaneous nephrolithotomy (PCNL) is challenging. Using the single semirigid dilator, also called "one-shot" or "one-stage" is a good alternative to routine telescopic metal dilators to reduce X-ray exposure. Our aim was to compare the single semirigid one-shot dilator with a telescopic metal dilator in PCNL. The intraoperative status was evaluated in 100 consecutive patients randomly assigned to two equal groups undergoing PCNL either with the one-shot (group A) or telescopic technique (group B). No significant difference in stone burden and location existed between the groups (P > 0.05). The mean age of group A and group B was 44.8 ± 15 and 45.6 ± 14 years, respectively (P = 0.78). The mean operation time was 51.14 ± 40.85 min in group A and 57.00 ± 38.85 min in group B (P = 0.46). The mean X-ray exposure time was 41.2 ± 17 and 48.4 ± 15 s in group A and group B, respectively (P = 0.03). The stone-free rate was 94 % (n = 47) in group A and 84 % (n = 42) in group B (P = 0.10). The mean hemoglobin drop was 1.26 ± 0.09 and 1.44 ± 0.11 g/dl in group A and group B, respectively (P = 0.09). The one-shot technique is feasible, safe, and well tolerated in patients undergoing PCNL. In addition to lack of complications, the method also provides less radiation exposure for urologists and nursing teams.

The Clinical Significance of Digital Examination-Indicated Cerclage in Women with a Dilated Cervix at 14 0/7 - 29 6/7 Weeks

PubMed Central

Ko, Hyun Sun; Jo, Yun Seong; Kil, Ki Cheol; Chang, Ha Kyun; Park, Yong-Gyu; Park, In Yang; Lee, Guisera; Kim, Sajin; Shin, Jong Chul

2011-01-01

Objective. This study was to compare pregnancy outcomes between cerclage and expectant management in wemen with a dilated cervix. Design. Retrospective multicenter cohort study. Setting. Five hospitals of Catholic University Medical Center Network in Korea. Population. A total of 173 women between 14 0/7 and 29 6/7 weeks' gestation with cervical dilation of 1 cm or greater by digital examination. Methods. Pregnancy outcomes were compared according to cerclage or expectant management, with the use of propensity-score matching. Main Outcome Measures. Primary outcome was time from presentation until delivery (weeks). Secondary outcomes were gestational age at delivery, neonatal survival, morbidity, preterm birth, and so on. Results. Of 173 women, 116 received a cerclage (cerclage group), and 57 were managed expectantly without cerclage (expectant group). Cervical dilation at presentation, and the use of amniocentesis performed to exclude subclinical chorioamnionitis differed between two groups. In the overall matched cohort, there was significant difference in the time from presentation until delivery (cerclage vs. expectant group, 10.6±6.2 vs. 2.9±3.2 weeks, p <0.0001). While there was no significant difference in the neonatal survival between two groups, there werelower neonatal morbidity as well as higher pregnancy maintenance rate at 28, 32, 34 and 37 weeks' gestation in the cerclage group, compared with the expectant group. Conclusion. This study suggests that digital examination-indicated cerclage appears to prolong gestation and decrease neonatal morbidity, compared with expectant management in women with cervical dilation between 14 0/7 and 29 6/7 weeks. PMID:21960743

Infrared Video Pupillography Coupled with Smart Phone LED for Measurement of Pupillary Light Reflex.

PubMed

Chang, Lily Yu-Li; Turuwhenua, Jason; Qu, Tian Yuan; Black, Joanna M; Acosta, Monica L

2017-01-01

Clinical assessment of pupil appearance and pupillary light reflex (PLR) may inform us the integrity of the autonomic nervous system (ANS). Current clinical pupil assessment is limited to qualitative examination, and relies on clinical judgment. Infrared (IR) video pupillography combined with image processing software offer the possibility of recording quantitative parameters. In this study we describe an IR video pupillography set-up intended for human and animal testing. As part of the validation, resting pupil diameter was measured in human subjects using the NeurOptics ™ (Irvine, CA, USA) pupillometer, to compare against that measured by our IR video pupillography set-up, and PLR was assessed in guinea pigs. The set-up consisted of a smart phone with a light emitting diode (LED) strobe light (0.2 s light ON, 5 s light OFF cycles) as the stimulus and an IR camera to record pupil kinetics. The consensual response was recorded, and the video recording was processed using a custom MATLAB program. The parameters assessed were resting pupil diameter (D1), constriction velocity (CV), percentage constriction ratio, re-dilation velocity (DV) and percentage re-dilation ratio. We report that the IR video pupillography set-up provided comparable results as the NeurOptics ™ pupillometer in human subjects, and was able to detect larger resting pupil size in juvenile male guinea pigs compared to juvenile female guinea pigs. At juvenile age, male guinea pigs also had stronger pupil kinetics for both pupil constriction and dilation. Furthermore, our IR video pupillography set-up was able to detect an age-specific increase in pupil diameter (female guinea pigs only) and reduction in CV (male and female guinea pigs) as animals developed from juvenile (3 months) to adult age (7 months). This technique demonstrated accurate and quantitative assessment of pupil parameters, and may provide the foundation for further development of an integrated system useful for clinical applications.

The relationship of systemic markers of renal function and vascular function with retinal blood vessel responses.

PubMed

Heitmar, R; Varma, C; De, P; Lau, Y C; Blann, A D

2016-11-01

To test the hypothesis of a significant relationship between systemic markers of renal and vascular function (processes linked to cardiovascular disease and its development) and retinal microvascular function in diabetes and/or cardiovascular disease. Ocular microcirculatory function was measured in 116 patients with diabetes and/or cardiovascular disease using static and continuous retinal vessel responses to three cycles of flickering light. Endothelial function was evaluated by von Willebrand factor (vWf), endothelial microparticles and soluble E selectin, renal function by serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR). HbA1c was used as a control index. Central retinal vein equivalence and venous maximum dilation to flicker were linked to HbA1c (both p < 0.05). Arterial reaction time was linked to serum creatinine (p = 0.036) and eGFR (p = 0.039); venous reaction time was linked to creatinine clearance (p = 0.018). Creatinine clearance and eGFR were linked to arterial maximum dilatation (p < 0.001 and p = 0.003, respectively) and the dilatation amplitude (p = 0.038 and p = 0.048, respectively) responses in the third flicker cycle. Of venous responses to the first flicker cycle, HbA1c was linked to the maximum dilation response (p = 0.004) and dilatation amplitude (p = 0.017), vWf was linked to the maximum constriction response (p = 0.016), and creatinine clearance to the baseline diameter fluctuation (p = 0.029). In the second flicker cycle, dilatation amplitude was linked to serum creatinine (p = 0.022). Several retinal blood vessel responses to flickering light are linked to glycaemia and renal function, but only one index is linked to endothelial function. Renal function must be considered when interpreting retinal vessel responses.

Heart rate turbulence after ventricular premature beats in healthy Doberman pinschers and those with dilated cardiomyopathy.

PubMed

Harris, J D; Little, C J L; Dennis, J M; Patteson, M W

2017-10-01

To describe the measurement of heart rate turbulence (HRT) after ventricular premature beats and compare HRT in healthy Doberman pinschers and those with dilated cardiomyopathy (DCM), with and without congestive heart failure (CHF). Sixty-five client-owned Dobermans: 20 healthy (NORMAL), 31 with preclinical DCM and 14 with DCM and CHF (DCM + CHF). A retrospective study of data retrieved from clinical records and ambulatory ECG (Holter) archives, including data collected previously for a large-scale prospective study of Dobermans with preclinical DCM. Holter data were reanalysed quantitatively, including conventional time-domain heart rate variability and the HRT parameters turbulence onset and turbulence slope. Heart rate turbulence could be measured in 58/65 dogs. Six Holter recordings had inadequate ventricular premature contractions (VPCs) and one exhibited VPCs too similar to sinus morphology. Heart rate turbulence parameter, turbulence onset, was significantly reduced in DCM dogs, whereas conventional heart rate variability measures were not. Heart rate variability and HRT markers were reduced in DCM + CHF dogs as expected. Heart rate turbulence can be measured from the majority of good quality standard canine 24-hour Holter recordings with >5 VPCs. Turbulence onset is significantly reduced in Dobermans with preclinical DCM which indicates vagal withdrawal early in the course of disease. Heart rate turbulence is a powerful prognostic indicator in human cardiac disease which can be measured from standard 24-hour ambulatory ECG (Holter) recordings using appropriate computer software. Further studies are warranted to assess whether HRT may be of prognostic value in dogs with preclinical DCM and in other canine cardiac disease. Copyright © 2017 Elsevier B.V. All rights reserved.

A morpho-functional study using PEP/LVET ratio and global longitudinal strain in patients with dilated cardiomyopathy.

PubMed

Corîci, Oana Maria; Tănasie, Cornelia Andreea; Alexandru, Dragoş Ovidiu; Florescu, Mihaela Corina; Comănescu, Maria Victoria; Kamal, Kamal Constantin; Ţenea-Cojan, Tiberiu Ştefăniţă; Iancău, Maria; Dinescu, Sorin Nicolae

2018-01-01

To assess left ventricular (LV) systolic function and morphology in patients with severe dilated cardiomyopathy (DCM), using both conventional and a complex technique, speckle-tracking echocardiography, and evaluate the correlation between pre-ejection period and left ventricular ejection period (PEP/LVET) ratio, global longitudinal strain (GLS), and severity of the condition. Seventeen patients were enrolled after rigorous criteria. Echocardiography was performed in conventional and speckle-tracking mode, in all patients with DCM, in sinus rhythm. LV dimensions, volumes and ejection fraction (LVEF) were measured. PEP/LVET ratio was obtained from apical 5-chamber axis and was defined as the time between QRS onset and LV ejection reported to LV ejection period. Speckle-tracking imaging was performed in offline mode and GLS was obtained from parasternal 4-, 3-, 2-chamber apical view, by averaging longitudinal peak systolic strain of all 17 LV-segments. New York Heart Association (NYHA) functional class correlated significantly with LVEF (-0.82; p=0.0006), PEP/LVET (0.86; p=0.001) or GLS (0.85; p=0.0002). Considerable correlations were between mitral regurgitation (MR) severity and LVEF (-0.65; p=0.01) or PEP/LVET (0.69; p=0.0059), but higher were between MR severity and GLS (0.76; p=0.0018). Tricuspid regurgitation (TR) grading correlated statistically with LVEF (-0.62; p=0.01), PEP/LVET and GLS (0.6; p=0.018; and 0.62; p=0.014, respectively). As opposed to the parameters in conventional echocardiography, GLS correlated with DCM etiology (p=0.0046) and with the gender (p=0.048). This study demonstrates that, in patients with DCM, assessment of cardiac dyssynchrony can be accurately accomplished by combining parameters in conventional and in speckle-tracking echocardiography.

A prospective study of survival and recurrence following the acute gastric dilatation-volvulus syndrome in 136 dogs.

PubMed

Glickman, L T; Lantz, G C; Schellenberg, D B; Glickman, N W

1998-01-01

Dogs (n = 136) with gastric dilatation-volvulus (GDV) syndrome were followed over time to measure recurrence and mortality rates and to identify prognostic factors. Thirty-three (24.3%) died or were euthanized during the first seven days. Of 85 cases that were followed for up to three years, nine (10.6%) cases each had a recurrence of GDV and seven (8.2%) cases died or were euthanized. The median survival times for cases that had gastropexies and those that did not were 547 and 188 days, respectively. Depressed or comatose cases on admission were three and 36 times, respectively, more likely to die than alert cases, while cases with gastric necrosis were 11 times more likely to die.

Delayed versus immediate pushing in second stage of labor.

PubMed

Kelly, Mary; Johnson, Eileen; Lee, Vickie; Massey, Liz; Purser, Debbie; Ring, Karen; Sanderson, Stephanye; Styles, Juanita; Wood, Deb

2010-01-01

Comparison of two different methods for management of second stage of labor: immediate pushing at complete cervical dilation of 10 cm and delayed pushing 90 minutes after complete cervical dilation. This study was a randomized clinical trial in a labor and delivery unit of a not-for-profit community hospital. A sample of 44 nulliparous mothers with continuous epidural anesthesia were studied after random assignment to treatment groups. Subjects were managed with either immediate or delayed pushing during the second stage of labor at the time cervical dilation was complete. The primary outcome measure was the length of pushing during second stage of labor. Secondary outcomes included length of second stage of labor, maternal fatigue and perineal injuries, and fetal heart rate decelerations. Two-tailed, unpaired Student's t-tests and Chi-square analysis were used for data analysis. Level of significance was set at p < .01 following a Bonferroni correction for multiple t-tests. A total of 44 subjects received the study intervention (N = 28 immediate pushing; N = 16 delayed pushing). The delayed pushing group had significantly shorter amount of time spent in pushing compared with the immediate pushing group (38.9 +/- 6.9 vs. 78.7 +/- 7.9 minutes, respectively, p = .002). Maternal fatigue scores, perineal injuries, and fetal heart rate decelerations were similar for both groups. Delaying pushing for up to 90 minutes after complete cervical dilation resulted in a significant decrease in the time mothers spent pushing without a significant increase in total time in second stage of labor.In clinical practice, healthcare providers sometimes resist delaying the onset of pushing after second stage of labor has begun because of a belief it will increase labor time. This study's finding of a 51% reduction in pushing time when mothers delay pushing for up to 90 minutes, with no significant increase in overall time for second stage of labor, disputes that concern.

[Conservative treatment of benign esophageal strictures using dilation. Analysis of 500 cases].

PubMed

Andreollo, N A; Lopes, L R; Inogutti, R; Brandalise, N A; Leonardi, L S

2001-01-01

The benign esophageal stenoses (BES) are common complications owing to many etiologies: gastroesophageal reflux, ingestion of corrosive agents, esophageal surgery, radiotherapy, postendoscopic variceal sclerotherapy, drug ingestion, prolonged nasogastric intubation, extrinsic compression and esophageal webs. Esophageal dilatations are worldwide recommended to treat this complication, employing dilators of many types and diameters and facilitating the food ingestion. Evaluation of the results and advantages of the conservative treatment of the BES using esophageal dilatations, in outpatient service of upper digestive endoscopy. During the period from 1981 to 1999, 500 patients with BES were treated and followed up at the Gastrocenter - UNICAMP, in an individually Program of Esophageal Dilatation for each case. The highest number of cases was under ages from 31 to 60 years old (52,8%), and males (59,2%). The most predominant etiologies were: peptic stenosis (30,4%), caustic ingestion (23,6%), anastomosis (23,2%), megaesophagus (8,0%) and prolonged nasogastric ingestion entubation (6,4%), totalizing 91,6% of the BES. Most of patients (94,2%) were submitted to the maximum of 25 dilations. Dilators from 10,5 to 16 mm were employed in 95,6% of the cases. The duration of the treatment was 24 months in 76,2% of the BES. Esophageal perforations occurred in 6 patients (1,2%), without mortality. Were considered excellent, good and bad results, respectively in 76,2%, 18,2% and 5,6% of the cases. On the other hand, excellent results were recorded in 81,0% of the peptic stenosis, 66,1% of the caustic stenosis and 82,7% of the anastomotic stenosis. The conservative treatment failed in 9,3% of the caustic stenosis, 4,3% of the anastomotic stenosis and 3,9% of the peptic stenosis. Thus, the caustic stenosis were unsuccessfull in the highest percentage of unsuccessful. The conservative treatment using guidewire dilators (Savary-Gilliard and Eder-Puestow) is the first choice in the BES, is effective for long time, with short complications and the surgical treatment is indicated only when the dilatations failed.

Role of procalcitonin in predicting dilating vesicoureteral reflux in young children hospitalized with a first febrile urinary tract infection.

PubMed

Sun, Hai-Lun; Wu, Kang-Hsi; Chen, Shan-Ming; Chao, Yu-Hua; Ku, Min-Sho; Hung, Tong-Wei; Liao, Pen-Fen; Lue, Ko-Huang; Sheu, Ji-Nan

2013-09-01

The aim of this article was to assess the usefulness of procalcitonin (PCT) as a marker for predicting dilating (grades III-V) vesicoureteral reflux (VUR) in young children with a first febrile urinary tract infection. Children ≤2 years of age with a first febrile urinary tract infection were prospectively evaluated. Serum samples were tested for PCT at the time of admission to a tertiary hospital. All children underwent renal ultrasonography (US), Tc-dimercaptosuccinic acid renal scan, and voiding cystourethrography. The diagnostic characteristics of PCT test for acute pyelonephritis and dilating VUR were calculated. Of 272 children analyzed (168 boys and 104 girls; median age, 5 months), 169 (62.1%) had acute pyelonephritis. There was VUR demonstrated in 97 (35.7%), including 70 (25.7%) with dilating VUR. The median PCT value was significantly higher in children with VUR than in those without (P < 0.001). Using a PCT cutoff value of ≥1.0 ng/mL, the sensitivity and negative predictive value for predicting dilating VUR were 94.3% and 95.4%, respectively, for PCT, and 97.1% and 97.8%, respectively, for the combined PCT and US studies, whereas the positive and negative likelihood ratios were 2.03 and 0.107, respectively, for PCT, and 1.72 and 0.067, respectively, for the combined studies. By multivariate analysis, high PCT values and abnormalities on US were independent predictors of dilating VUR. PCT is useful for diagnosing acute pyelonephritis and predicting dilating VUR in young children with a first febrile urinary tract infection. A voiding cystourethrography is indicated only in children with high PCT values (≥1.0 ng/mL) and/or abnormalities found on a US.

Losartan added to β-blockade therapy for aortic root dilation in Marfan syndrome: a randomized, open-label pilot study.

PubMed

Chiu, Hsin-Hui; Wu, Mei-Hwan; Wang, Jou-Kou; Lu, Chun-Wei; Chiu, Shuenn-Nan; Chen, Chun-An; Lin, Ming-Tai; Hu, Fu-Chang

2013-03-01

To assess the tolerability and efficacy of the investigational use of the angiotensin II receptor blocker losartan added to β-blockade (BB) to prevent progressive aortic root dilation in patients with Marfan syndrome (MFS). Between May 1, 2007, and September 31, 2011, 28 patients with MFS (11 males [39%]; mean ± SD age, 13.1±6.3 years) with recognized aortic root dilation (z score >2.0) and receiving BB (atenolol or propranolol) treatment were enrolled. They were randomized to receive BB (BB: 13 patients) or β-blockade and losartan (BB-L: 15 patients) for 35 months. In the BB-L group, aortic root dilation was reduced with treatment, and the annual dilation rate of the aortic root was significantly lower than that of the BB group (0.10 mm/yr vs 0.89 mm/yr; P=.02). The absolute aortic diameters at the sinus of Valsalva, annulus, and sinotubular junction showed similar trends, with a reduced rate of dilation in the BB-L group (P=.02, P=.03, and P=.03, respectively). Five patients (33%) treated with BB-L were noted to have a reduced aortic root diameter. However, the differences between the groups regarding changes in aortic stiffness and cross-sectional compliance were not statistically significant. This randomized, open-label, active controlled trial mostly based on a pediatric population demonstrated for the first time that losartan add-on BB therapy is safe and provides more effective protection to slow the progression of aortic root dilation than does BB treatment alone in patients with MFS. clinicaltrials.gov Identifier: NCT00651235. Copyright © 2013 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Lorentz symmetry violation and UHECR experiments

NASA Astrophysics Data System (ADS)

Gonzalez-Mestres, L.

2001-08-01

Lorentz symmetry violation (LSV) at Planck scale can be tested through ultra-high energy cosmic rays (UHECR). We discuss deformed Lorentz symmetry (DLS) and energy non-conservation (ENC) patterns where the effective LSV parameter varies like the square of the momentum scale (e.g. quadratically de-formed relativistic kinematics, QDRK). In such patterns, a ≈ 106 LSV at Planck scale would be enough to produce observable effects on the properties of cosmic rays at the ≈ 1020 eV scale: absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of any parton model and of standard formulae for Lorentz contraction and time dilation... Its phenomeno-logical implications are compatible with existing data. Precise signatures are discussed in several patterns. If the effective LSV or ENC parameter is taken to vary linearly with the momentum scale (e.g. linearly deformed relativistic kinematics, LDRK), contradictions seem to arise with UHECR data. Conse-quences are important for UHECR and high-energy gamma-ray exper iments, as well as for high-energy cosmic rays and gravitational waves.

Systolic and diastolic assessment by 3D-ASM segmentation of gated-SPECT Studies: a comparison with MRI

NASA Astrophysics Data System (ADS)

Tobon-Gomez, C.; Bijnens, B. H.; Huguet, M.; Sukno, F.; Moragas, G.; Frangi, A. F.

2009-02-01

Gated single photon emission tomography (gSPECT) is a well-established technique used routinely in clinical practice. It can be employed to evaluate global left ventricular (LV) function of a patient. The purpose of this study is to assess LV systolic and diastolic function from gSPECT datasets in comparison with cardiac magnetic resonance imaging (CMR) measurements. This is achieved by applying our recently implemented 3D active shape model (3D-ASM) segmentation approach for gSPECT studies. This methodology allows for generation of 3D LV meshes for all cardiac phases, providing volume time curves and filling rate curves. Both systolic and diastolic functional parameters can be derived from these curves for an assessment of patient condition even at early stages of LV dysfunction. Agreement of functional parameters, with respect to CMR measurements, were analyzed by means of Bland-Altman plots. The analysis included subjects presenting either LV hypertrophy, dilation or myocardial infarction.

Measurement of gravitational time dilation: An undergraduate research project

NASA Astrophysics Data System (ADS)

Burns, M. Shane; Leveille, Michael D.; Dominguez, Armand R.; Gebhard, Brian B.; Huestis, Samuel E.; Steele, Jeffrey; Patterson, Brian; Sell, Jerry F.; Serna, Mario; Gearba, M. Alina; Olesen, Robert; O'Shea, Patrick; Schiller, Jonathan

2017-10-01

General relativity predicts that clocks run more slowly near massive objects. The effect is small—a clock at sea level lags behind one 1000 m above sea level by only 9.4 ns/day. Here, we demonstrate that a measurement of this effect can be done by undergraduate students. Our paper describes an experiment conducted by undergraduate researchers at Colorado College and the United States Air Force Academy to measure gravitational time dilation. The measurement was done by comparing the signals generated by a GPS frequency standard (sea-level time) to a Cs-beam frequency standard at seven different altitudes above sea level. We found that our measurements are consistent with the predictions of general relativity.

A predictive model for canine dilated cardiomyopathy-a meta-analysis of Doberman Pinscher data.

PubMed

Simpson, Siobhan; Edwards, Jennifer; Emes, Richard D; Cobb, Malcolm A; Mongan, Nigel P; Rutland, Catrin S

2015-01-01

Dilated cardiomyopathy is a prevalent and often fatal disease in humans and dogs. Indeed dilated cardiomyopathy is the third most common form of cardiac disease in humans, reported to affect approximately 36 individuals per 100,000 individuals. In dogs, dilated cardiomyopathy is the second most common cardiac disease and is most prevalent in the Irish Wolfhound, Doberman Pinscher and Newfoundland breeds. Dilated cardiomyopathy is characterised by ventricular chamber enlargement and systolic dysfunction which often leads to congestive heart failure. Although multiple human loci have been implicated in the pathogenesis of dilated cardiomyopathy, the identified variants are typically associated with rare monogenic forms of dilated cardiomyopathy. The potential for multigenic interactions contributing to human dilated cardiomyopathy remains poorly understood. Consistent with this, several known human dilated cardiomyopathy loci have been excluded as common causes of canine dilated cardiomyopathy, although canine dilated cardiomyopathy resembles the human disease functionally. This suggests additional genetic factors contribute to the dilated cardiomyopathy phenotype.This study represents a meta-analysis of available canine dilated cardiomyopathy genetic datasets with the goal of determining potential multigenic interactions relating the sex chromosome genotype (XX vs. XY) with known dilated cardiomyopathy associated loci on chromosome 5 and the PDK4 gene in the incidence and progression of dilated cardiomyopathy. The results show an interaction between known canine dilated cardiomyopathy loci and an unknown X-linked locus. Our study is the first to test a multigenic contribution to dilated cardiomyopathy and suggest a genetic basis for the known sex-disparity in dilated cardiomyopathy outcomes.

Racial variations in interfacial behavior of lipids extracted from worn soft contact lenses.

PubMed

Svitova, Tatyana F; Lin, Meng C

2013-12-01

To explore interfacial behaviors and effects of temperature and dilatation on dynamic properties of multilayered human tear lipids extracted from silicone hydrogel (SiH) lenses worn by asymptomatic Asian and white subjects. Interfacial properties of lipids extracted from Focus N&D lenses worn by 14 subjects continuously for 1 month were studied. The lipids were deposited on an air bubble immersed in a model tear electrolyte (MTE) solution to form 100 ± 20-nm-thick films. Surface pressure was recorded during slow expansion/contraction cycles to evaluate compressibility and hysteresis of lipid films. Films were also subjected to fast step-strain dilatations at temperatures of 22 to 45°C for their viscoelastic property assessment. Isocycles for Asian and white lipids were similar at low surface pressures but had distinctly different compressibility and hysteresis at dynamic pressures exceeding 30 mN/m. Rheological parameters of reconstituted lipids were also dissimilar between Asian and white. The elastic modulus E∞ for white lipids was 1.5 times higher than that for Asian lipids, whereas relaxation time (t) was on average 1.3 times higher for Asian. No significant changes were observed in rheological properties of both Asian and white lipids when temperature increased from 22.0 to 36.5°C. However, for white lipids, E∞ reduced considerably at temperatures higher than 42.0°C, whereas t remained unchanged. For Asian lipids, both E∞ and t started to decline as temperature increased to 38°C and higher. Higher elastic modulus of white lipids and elasticity threshold at certain deformations indicate stronger structure and intermolecular interactions as compared with more viscous Asian lipids. The differences in interfacial behaviors between Asian and white lipids may be associated with the differences in their chemical compositions.

Adherence to Vaginal Dilation Following High Dose Rate Brachytherapy for Endometrial Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, Lois C., E-mail: Lois.Friedman@UHhospitals.org; Abdallah, Rita; Schluchter, Mark

Purpose: We report demographic, clinical, and psychosocial factors associated with adherence to vaginal dilation and describe the sexual and marital or nonmarital dyadic functioning of women following high dose rate (HDR) brachytherapy for endometrial cancer. Methods and Materials: We retrospectively evaluated women aged 18 years or older in whom early-stage endometrial (IAgr3-IIB) cancers were treated by HDR intravaginal brachytherapy within the past 3.5 years. Women with or without a sexual partner were eligible. Patients completed questionnaires by mail or by telephone assessing demographic and clinical variables, adherence to vaginal dilation, dyadic satisfaction, sexual functioning, and health beliefs. Results: Seventy-eight ofmore » 89 (88%) eligible women with early-stage endometrial cancer treated with HDR brachytherapy completed questionnaires. Only 33% of patients were adherers, based on reporting having used a dilator more than two times per week in the first month following radiation. Nonadherers who reported a perceived change in vaginal dimension following radiation reported that their vaginas were subjectively smaller after brachytherapy (p = 0.013). Adherers reported more worry about their sex lives or lack thereof than nonadherers (p = 0.047). Patients reported considerable sexual dysfunction following completion of HDR brachytherapy. Conclusions: Adherence to recommendations for vaginal dilator use following HDR brachytherapy for endometrial cancer is poor. Interventions designed to educate women about dilator use benefit may increase adherence. Although sexual functioning was compromised, it is likely that this existed before having cancer for many women in our study.« less

Management Options for Twisted Gastric Tube after Laparoscopic Sleeve Gastrectomy.

PubMed

Abd Ellatif, Mohamed E; Abbas, Ashraf; El Nakeeb, Ayman; Magdy, Alaa; Salama, Asaad F; Bashah, Moataz M; Dawoud, Ibrahim; Gamal, Maged Ali; Sargsyan, Davit

2017-09-01

This study aims to determine the incidence, etiology, and management options for symptomatic gastric obstruction caused by axially twisted sleeve gastrectomy. In this retrospective study, we reviewed medical charts of all morbidly obese patients who underwent laparoscopic sleeve gastrectomy. Patients who developed gastric obstruction symptoms and were diagnosed with twisted sleeve gastrectomy were identified and included in this study. From October 2005 to December 2015, there are 3634 morbidly obese patients who underwent laparoscopic sleeve gastrectomy (LSG). Eighty-six (2.3%) patients developed symptoms of gastric obstruction. Forty-five (1.23%) patients were included in this study. The mean time of presentation was 59.8 days after surgery. Upper GI contrast study was done routinely, and it was positive for axial twist in 37 (82%) patients. Abdominal CT with oral and IV contrast was done in eight (18%) when swallow study was equivocal. Endoscopic treatment was successful in 43 patients (95.5%). Sixteen patients were successfully managed by endoscopic stenting, and 29 patients had balloon dilation. The average numbers of dilation sessions were 1.7. Out of these 29 patients, 18 responded well to a single session of dilatation and did not require any further dilatation sessions. Two patients who failed to respond to three subsequent sessions of balloon dilation underwent laparoscopic adhesiolysis and gastropexy. Endoscopic stenting is an effective tool in management of axial rotation of sleeved stomach. Balloon dilation can also be effective in selected cases. Few cases might require laparoscopic adhesiolysis and gastropexy.

Transthoracic ultrasound guided balloon dilation of cor triatriatum dexter in 2 Rottweiler puppies.

PubMed

Birettoni, F; Caivano, D; Bufalari, A; Giorgi, M E; Miglio, A; Paradies, P; Porciello, F

2016-12-01

Balloon dilation was performed in two Rottweiler puppies with cor triatriatum dexter and clinical signs of ascites using transthoracic echocardiographic guidance. The dogs were positioned on a standard echocardiography table in right lateral recumbency, and guide wires and balloon catheters were imaged by echocardiographic views optimized to allow visualization of the defect. The procedures were performed successfully without complications and clinical signs were resolved completely in both cases. Guide wires and balloon catheters appeared hyperechoic on transthoracic echocardiography image and could be clearly monitored and guided in real-time. These two cases demonstrate that it is possible to perform balloon catheter dilation of cor triatriatum dexter under transthoracic guidance alone. Copyright © 2016 Elsevier B.V. All rights reserved.

Treatment of male urethral strictures - possible reasons for the use of repeated dilatation or internal urethrotomy rather than urethroplasty.

PubMed

Heyns, C F; van der Merwe, J; Basson, J; van der Merwe, A

2012-07-16

To investigate the possible reasons for repeated urethral dilatation or optical internal urethrotomy rather than urethroplasty in the treatment of male urethral strictures. Men referred to the stricture clinic of our institution during the period April 2007 - March 2008 were reviewed and the operative urological procedures performed in the same period were analysed. Statistical analysis was performed using Student's t-test and Fisher's exact test (p<0.05 statistically significant). The mean age of the 125 men was 49.9 years (range 12.8 - 93.4 years). Previous stricture treatment had been given 1 - 2, 3 - 4 and 5 - 6 times in 52%, 32% and 12% of patients, respectively (4% had not undergone treatment). In these groups, previous treatment was dilatation in 70%, 76% and 72%, urethrotomy in 26%, 15% and 28%, and urethroplasty in 4%, 9% and 0, respectively. The group with 5 - 6 compared with 1 - 2 previous treatments was significantly older (mean age 60.2 v. 46.6 years) and had a significantly greater proportion with underlying co-morbidities (80% v. 52%). The group that had undergone urethroplasty compared with 5 - 6 repeated dilatations or urethrotomies was significantly younger (mean age 48.2 v. 60.2 years) with a lower prevalence of co-morbidities (47% v. 80%). During the study period urethroplasty was performed in 16 (2%) of 821 inpatients, whereas 55 men were seen who had undergone ≥3 previous procedures, indicating that urethroplasty was performed in less than one-third of cases in which it would have been the optimal treatment. Owing to limited theatre time, procedures indicated for malignancy, urolithiasis, renal failure and congenital anomalies were performed more often than urethroplasty. Factors that possibly influenced the decision to perform repeated urethrotomy or dilatation instead of urethroplasty were limited theatre time, increased patient age and the presence of underlying co-morbidities.

A New Alternative for Difficult Ureter in Adult Patients: No Need to Dilate Ureter via a Balloon or a Stent with the Aid of 4.5F Semirigid Ureteroscope.

PubMed

Söylemez, Haluk; Yıldırım, Kadir; Utangac, Mehmet Mazhar; Aydoğan, Tahsin Batuhan; Ezer, Mehmet; Atar, Murat

2016-06-01

To investigate the effectivity of 4.5F ultrathin ureteroscope (UT-URS) without any need for active or passive dilation in the treatment of adult patient population in whom ureteral orifices cannot be engaged using conventional URS. Among a total of 512 adult patients who had undergone URS between April 2012 and November 2015 in our department for diagnostic or therapeutic purposes, 43 (8.4%) patients required ureteral dilation because we could not engage ureteral orifice. In adult patients in whom we could not engage ureteral orifice with 7.5F and 8F semirigid URS, we tried to complete the operation using 4.5F UT-URS without resorting to dilation. Age and gender of the patients, indication for operation, stone size, location, operative times, laterality of stone(s), stone-free rates, length of hospital stay, and complications were recorded. Mean age of the patients was 34.5 ± 11.2 (21-66) years. The patients had undergone operations for ureteral stone (n = 39), unexplained hydronephrosis (n = 2), and ureteral stenosis (n = 2). Mean stone size was 8.2 ± 2.3 (4-18) mm. Mean operative time was 64.2 ± 13.5 minutes. In 37 of 39 patients, a complete stone-free rate (94.8%) was achieved. Mean length of hospital stay was 8.9 ± 5.8 hours. It has been demonstrated that in an adult patient population in whom ureteral orifices cannot be engaged using conventional URS, ureteral access could be achieved with 4.5F UT-URS without any need for dilation. At the same time, use of 4.5F UT-URS resulted in an acceptable treatment success and lower complication rates in most of these patients without the need for a second session.

Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy

PubMed Central

Przywara, John F.; Abel, Steven B.; Peacock, John T.; Shott, Susan

2014-01-01

This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy. PMID:25320388

Factors associated with complications or failure of endoscopic balloon dilation of anastomotic stricture secondary to Roux-en-Y gastric bypass surgery.

PubMed

de Moura, Eduardo G H; Orso, Ivan R B; Aurélio, Eduardo F; de Moura, Eduardo T H; de Moura, Diogo T H; Santo, Marco A

2016-01-01

Roux-en-Y gastric bypass is a commonly used technique of bariatric surgery. One of the most important complications is gastrojejunal anastomotic stricture. Endoscopic balloon dilation appears to be well tolerated and effective, but well-designed randomized, controlled trials have not yet been conducted. Identify factors associated with complications or failure of endoscopic balloon dilation of anastomotic stricture secondary to Roux-en-Y gastric bypass surgery. Gastrointestinal endoscopy service, university hospital, Brazil. The records of 64 patients with anastomotic stricture submitted to endoscopic dilation with hydrostatic balloon dilation were reviewed. Information was collected on gastric pouch length, anastomosis diameter before dilation, number of dilation sessions, balloon diameter at each session, anastomosis diameter after the last dilation session, presence of postsurgical complications, endoscopic complications, and outcome of dilation. Comparisons were made among postsurgical and endoscopic complications; number of dilations, balloon diameter; anastomosis diameter before dilation; and dilation outcome. Success of dilation treatment was 95%. Perforation was positively and significantly associated with the number of dilation sessions (P = .03). Highly significant associations were found between ischemic segment and perforation (P<.001) and between ischemic segment and bleeding (P = .047). Ischemic segment (P = .02) and fistula (P = .032) were also associated with dilation failure. Ischemic segment and fistula were found to be important risk factors for balloon dilation failure. The greater the number of dilation sessions, the greater the number of endoscopic complications. Copyright © 2016 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta.

PubMed

Pasta, S; Gentile, G; Raffa, G M; Bellavia, D; Chiarello, G; Liotta, R; Luca, A; Scardulla, C; Pilato, M

2017-08-01

The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients. Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV (n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 ± 5.3 mm for BAV and 45.4 ± 10.0 mm for TAV) were compared. BAV phenotypes were stratified according to the leaflet fusion pattern and aortic shape. Systolic wall shear stress (WSS) of BAV patients was higher than TAV patients at the sinotubular junction (6.8 ± 3.3 N/m 2 for BAV and 3.9 ± 1.3 N/m 2 for TAV; p = .006) and mid-ascending aorta (9.8 ± 3.3 N/m 2 for BAV and 7.1 ± 2.3 N/m 2 for TAV; p = .040). A statistically significant difference in BAV versus TAV was also observed for the intramural stress along the ascending aorta (e.g., 2.54 × 10 5  ± 0.32 × 10 5  N/m 2 for BAV and 2.04 × 10 5  ± 0.34 × 10 5  N/m 2 for TAV; p < .001) and pressure index (0.329 ± 0.107 for BAV and 0.223 ± 0.139 for TAV; p = .030). Differences in the BAV phenotypes (i.e., BAV type 1 vs. BAV type 2) and aortopathy (i.e., isolated tubular vs. aortic root dilatations) were associated with asymmetric WSS distributions in the right anterior aortic wall and right posterior aortic wall, respectively. These findings suggest that valve mediated haemodynamic and structural parameters may be used to identify which regions of aortic wall are at greater stress and enable the development of a personalised approach for the diagnosis and management of aortic dilatation beyond traditional guidelines. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Evaluating the Learning Curve for Percutaneous Nephrolithotomy under Total Ultrasound Guidance.

PubMed

Song, Yan; Ma, YaNan; Song, YongSheng; Fei, Xiang

2015-01-01

To investigate the learning curve of percutaneous nephrolithotomy under total ultrasound guidance. One hundred and twenty consecutive PCNL operations under total ultrasound guidance performed by a novice surgeon in a tertiary referral center were studied. Operations were analyzed in cohorts of 15 to determine when a plateau was reached for the variables such as operation duration, ultrasound screening time, tract dilation time, stone-free rate and complication rate. Comparison was made with the results of a surgeon who had performed more than 1000 PCNLs. Fluoroscopy was not used at all during procedure. The mean operation time dropped from 82.5 min for the first 15 patients to a mean of 64.7 min for cases 46 through 60(P = 0.047). The ultrasound screening time was a peak of 6.4 min in the first 15 cases, whereas it dropped to a mean of 3.9 min for cases 46 through 60(P = 0.01). The tract dilation time dropped from 4.9 min for the first 15 patients to a mean of 3.8 min for cases 46 through 60(P = 0.036). The senior surgeon had a mean operating time, screening time and tract dilation time equivalent to those of the novice surgeon after 60 cases. There was no significant difference in stone free rate and complication rate. The competence of ultrasound guided PCNL is reached after 60 cases with good stone free rate and without major complications.

Dynamic Stability of the Rate, State, Temperature, and Pore Pressure Friction Model at a Rock Interface

NASA Astrophysics Data System (ADS)

Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

2018-05-01

In this article, we study numerically the dynamic stability of the rate, state, temperature, and pore pressure friction (RSTPF) model at a rock interface using standard spring-mass sliding system. This particular friction model is a basically modified form of the previously studied friction model namely the rate, state, and temperature friction (RSTF). The RSTPF takes into account the role of thermal pressurization including dilatancy and permeability of the pore fluid due to shear heating at the slip interface. The linear stability analysis shows that the critical stiffness, at which the sliding becomes stable to unstable or vice versa, increases with the coefficient of thermal pressurization. Critical stiffness, on the other hand, remains constant for small values of either dilatancy factor or hydraulic diffusivity, but the same decreases as their values are increased further from dilatancy factor (˜ 10^{ - 4} ) and hydraulic diffusivity (˜ 10^{ - 9} {m}2 {s}^{ - 1} ) . Moreover, steady-state friction is independent of the coefficient of thermal pressurization, hydraulic diffusivity, and dilatancy factor. The proposed model is also used for predicting time of failure of a creeping interface of a rock slope under the constant gravitational force. It is observed that time of failure decreases with increase in coefficient of thermal pressurization and hydraulic diffusivity, but the dilatancy factor delays the failure of the rock fault under the condition of heat accumulation at the creeping interface. Moreover, stiffness of the rock-mass also stabilizes the failure process of the interface as the strain energy due to the gravitational force accumulates in the rock-mass before it transfers to the sliding interface. Practical implications of the present study are also discussed.

Results of Eder-Puestow dilatation in the management of esophageal peptic strictures.

PubMed

Rago, E; Boesby, S; Spencer, J

1983-01-01

Eder-Puestow dilatation of esophageal strictures is a safe procedure. The treatment is followed by symptomatic improvement, but the effect of dilatation on the patients' nutritional state has so far not been reported. We have reviewed 33 patients with benign esophageal stricture with special regard to the effect of dilatation on body weight. A total of 152 dilatations was carried out. All patients had dysphagia, 32 patients had heartburn and 20 had regurgitation. Hiatus hernia was present in 29 patients. Thirteen patients had antireflux surgery; 10 operations were performed before, and four during the dilatation period. One patient required no further dilatations after operation. Dilators greater than 35 FG were passed in 85% of the dilatations. No serious complications occurred. Patients were followed for up to 5 yr (mean follow-up: 27 months). The mean interval between dilatations was 7 months. Body weight was recorded before and one month after dilatation on 78 occasions. There was a significant overall weight increase of 0.78 kg 1 month after dilatation. The mean weight increase was greater after the first dilatation (1.06 kg) than after subsequent ones (0.6 kg). We found that Eder-Puestow dilatation in patients with benign esophageal stricture led to symptomatic improvement and was followed by an increase in body weight.

Balloon dilatation of benign and malignant esophageal strictures. Blind retrograde balloon dilatation.

PubMed

Graham, D Y; Smith, J L

1985-06-01

Balloon esophageal dilatation offers many theoretical advantages (safety, speed, and patient comfort) over dilatation with mercury-filled bougies or with the Eder-Puestow system. The authors used balloon dilators in 22 patients with dysphagia secondary to benign or malignant strictures. Dilatation was performed with fluoroscopic guidance, blindly, or by a combination of these techniques. For "blind" stricture dilatation, an Eder-Puestow spring-tipped guide wire is placed into the stomach using a fiberoptic endoscope. The distance from the incisor teeth to the stricture is measured, and the balloon shaft is marked to indicate when the middle of the balloon is within the stricture. Dilatation is then performed using the antegrade or, the preferred, retrograde technique. Finally, the dilated stricture is calibrated by pulling an inflated balloon through the previously strictured area without difficulty. An attempt was made to achieve an esophageal diameter of 15 mm at the initial dilatation episode, and patient discomfort was used as a guide as to the final diameter. The balloon dilatation technique was highly successful, and a stricture diameter of 15 mm (45-47 French) was achieved at the initial dilatation in most instances. Malignant strictures were easily dilated. Balloon dilatation is convenient, effective, quick, and potentially safer than the previous Eder-Puestow or mercury-filled bougie techniques.

Solute induced relaxation in glassy polymers: Experimental measurements and nonequilibrium thermodynamic model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minelli, Matteo; Doghieri, Ferruccio

2014-05-15

Data for kinetics of mass uptake from vapor sorption experiments in thin glassy polymer samples are here interpreted in terms of relaxation times for volume dilation. To this result, both models from non-equilibrium thermodynamics and from mechanics of volume relaxation contribute. Different kind of sorption experiments have been considered in order to facilitate the direct comparison between kinetics of solute induced volume dilation and corresponding data from process driven by pressure or temperature jumps.

Dilation and Curettage (D&C)

MedlinePlus

... For Patients About ACOG Dilation and Curettage (D&C) Home For Patients Search FAQs Dilation and Curettage ( ... February 2016 PDF Format Dilation and Curettage (D&C) Special Procedures What is dilation and curettage (D& ...

Effect of repeated sprints on postprandial endothelial function and triacylglycerol concentrations in adolescent boys.

PubMed

Sedgwick, Matthew J; Morris, John G; Nevill, Mary E; Barrett, Laura A

2015-01-01

This study investigated whether repeated, very short duration sprints influenced endothelial function (indicated by flow-mediated dilation) and triacylglycerol concentrations following the ingestion of high-fat meals in adolescent boys. Nine adolescent boys completed two, 2-day main trials (control and exercise), in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial but completed 40 × 6 s maximal cycle sprints on day 1 of the exercise trial. On day 2, capillary blood samples were collected and flow-mediated dilation measured prior to, and following, ingestion of a high-fat breakfast and lunch. Fasting flow-mediated dilation and plasma triacylglycerol concentration were similar in the control and exercise trial (P > 0.05). In the control trial, flow-mediated dilation was reduced by 20% and 27% following the high-fat breakfast and lunch; following exercise these reductions were negated (main effect trial, P < 0.05; interaction effect trial × time, P < 0.05). The total area under the plasma triacylglycerol concentration versus time curve was 13% lower on day 2 in the exercise trial compared to the control trial (8.65 (0.97) vs. 9.92 (1.16) mmol · l(-1) · 6.5 h, P < 0.05). These results demonstrate that repeated 6 s maximal cycle sprints can have beneficial effects on postprandial endothelial function and triacylglycerol concentrations in adolescent boys.

Optical clocks and relativity.

PubMed

Chou, C W; Hume, D B; Rosenband, T; Wineland, D J

2010-09-24

Observers in relative motion or at different gravitational potentials measure disparate clock rates. These predictions of relativity have previously been observed with atomic clocks at high velocities and with large changes in elevation. We observed time dilation from relative speeds of less than 10 meters per second by comparing two optical atomic clocks connected by a 75-meter length of optical fiber. We can now also detect time dilation due to a change in height near Earth's surface of less than 1 meter. This technique may be extended to the field of geodesy, with applications in geophysics and hydrology as well as in space-based tests of fundamental physics.

Discrete linear canonical transforms based on dilated Hermite functions.

PubMed

Pei, Soo-Chang; Lai, Yun-Chiu

2011-08-01

Linear canonical transform (LCT) is very useful and powerful in signal processing and optics. In this paper, discrete LCT (DLCT) is proposed to approximate LCT by utilizing the discrete dilated Hermite functions. The Wigner distribution function is also used to investigate DLCT performances in the time-frequency domain. Compared with the existing digital computation of LCT, our proposed DLCT possess additivity and reversibility properties with no oversampling involved. In addition, the length of input/output signals will not be changed before and after the DLCT transformations, which is consistent with the time-frequency area-preserving nature of LCT; meanwhile, the proposed DLCT has very good approximation of continuous LCT.

Prognostic indicators for dogs with dilated cardiomyopathy.

PubMed

Borgarelli, Michele; Santilli, Roberto A; Chiavegato, David; D'Agnolo, Gino; Zanatta, Renato; Mannelli, Alessandro; Tarducci, Alberto

2006-01-01

The purpose of this study was to investigate the prognostic value of various clinical, ECG, echocardiographic, and Doppler echocardiographic variables in dogs with dilated cardiomyopathy. The relationship to survival of 11 variables was evaluated in 63 dogs. Studied variables were age at time of diagnosis, class of heart failure (HF), dyspnea, ascites, atrial fibrillation (AF), ejection fraction (EF), E-point septal separation, end-diastolic volume index, end-systolic volume index (ESV-I), and restrictive or nonrestrictive transmitral flow (TMF) pattern. Median survival time was 671 days (lower 95% confidence limit, 350 days). Survival curves showed that severity of HF, ascites, ESV-I greater than 140 mL/m2, EF less than 25%, and restrictive TMF pattern had a significant negative relation to survival time. Thirty-nine dogs with both sinus rhythm and AF presented adequate TMF recordings; in these dogs, after stratification by TMF pattern, the restrictive TMF pattern was the most important negative prognostic indicator. We conclude that in dogs with dilated cardiomyopathy the restrictive TMF pattern appears to represent a useful prognostic indicator. Class of HF, ascites, ESV-I, and EF are also useful indexes if an adequate TMF pattern is not recorded.

Moving Phones Tick Slower: Creating an Android App to Demonstrate Time Dilation

NASA Astrophysics Data System (ADS)

Underwood, Bret; Zhai, Yunxiao

2016-05-01

Smartphones and tablets are packed with sensors that allow us to take experimental data, essentially making them mobile physics labs. Apps exist that make it easy to capture and analyze data from these sensors, allowing users to study diverse phenomena such as free fall acceleration, the speed of sound, radioactivity, and many others. Commonly, the use of apps in the physics classroom focuses on existing apps rather than on the creation of apps themselves. This is for a good reason-writing an app usually requires advanced knowledge of programming languages and experience with app design. These skills are generally regarded as beyond the typical physics student. However, there are app development environments, such as MIT App Inventor 2 for Android, which make the process of creating an app and utilizing the sensors much more accessible to students. Putting the ability to create and configure apps within the reach of students can also help integrate computation into the curriculum. In this article, we discuss our creation of an Android app, Time Dilation Calculator, done as part of a senior undergraduate capstone project, which uses App Inventor and a mobile device's global positioning system (GPS) receiver to calculate the time dilation effect of special relativity.

Endoscopic balloon catheter dilatation via retrograde or static technique is safe and effective for cricopharyngeal dysfunction

PubMed Central

Chandrasekhara, Vinay; Koh, Joyce; Lattimer, Lakshmi; Dunbar, Kerry B; Ravich, William J; Clarke, John O

2017-01-01

AIM To evaluate the safety and efficacy of upper esophageal sphincter (UES) dilatation for cricopharyngeal (CP) dysfunction. To determine if: (1) indication for dilatation; or (2) technique of dilatation correlated with symptom improvement. METHODS All balloon dilatations performed at our institution from over a 3-year period were retrospectively analyzed for demographics, indication and dilatation site. All dilatations involving the UES underwent further review to determine efficacy, complications, and factors that predict success. Dilatation technique was separated into static (stationary balloon distention) and retrograde (brusque pull-back of a fully distended balloon across the UES). RESULTS Four hundred and eighty-eight dilatations were reviewed. Thirty-one patients were identified who underwent UES dilatation. Median age was 63 years (range 27-81) and 55% of patients were male. Indications included dysphagia (28 patients), globus sensation with evidence of UES dysfunction (2 patients) and obstruction to echocardiography probe with cricopharyngeal (CP) bar (1 patient). There was evidence of concurrent oropharyngeal dysfunction in 16 patients (52%) and a small Zenker’s diverticula (≤ 2 cm) in 7 patients (23%). Dilator size ranged from 15 mm to 20 mm. Of the 31 patients, 11 had dilatation of other esophageal segments concurrently with UES dilatation and 20 had UES dilatation alone. Follow-up was available for 24 patients for a median of 2.5 mo (interquartile range 1-10 mo), of whom 19 reported symptomatic improvement (79%). For patients undergoing UES dilatation alone, follow-up was available for 15 patients, 12 of whom reported improvement (80%). Nineteen patients underwent retrograde dilatation (84% response) while 5 patients had static dilatation (60% response); however, there was no significant difference in symptom improvement between the techniques (P = 0.5). Successful symptom resolution was also not significantly affected by dilator size, oropharyngeal dysfunction, Zenker’s diverticulum, age or gender (P > 0.05). The only complication noted was uvular edema and a shallow ulcer after static dilatation in one patient, which resolved spontaneously and did not require hospital admission. CONCLUSION UES dilatation with a through-the-scope balloon by either static or retrograde technique is safe and effective for the treatment of dysphagia due to CP dysfunction. To our knowledge, this is the first study evaluating retrograde balloon dilatation of the UES. PMID:28465785

Changes in ocular biometry and anterior chamber parameters after pharmacologic mydriasis and peripheral iridotomy in primary angle closure suspects.

PubMed

Razeghinejad, Mohammad Reza; Lashkarizadeh, Hamid; Nowroozzadeh, Mohammad Hossein; Yazdanmehr, Mohammad

2016-01-01

The aim of this study was to evaluate the effects of pharmacologic mydriasis and Peripheral Iridotomy (PI) on ocular biometry and anterior chamber parameters in primary angle closure suspects. In this prospective interventional case series, 21 primary angle closure suspects were enrolled. Intraocular pressure, refraction, ocular biometry (Lenstar, LS900), and anterior chamber parameters (Pentacam HR) were measured at four occasions: before PI (before and after mydriasis with phenylephrine) and two weeks after PI (before and after mydriasis). The study was conducted on both eyes and only one eye per patient, in random, was included in the analysis. The mean age of the participants was 60±7 years and 17 (81%) were female. There were no significant differences in intraocular pressure, refraction, keratometry, biometric and anterior chamber parameters between groups, except for anterior chamber volume, which showed increments with PI and mydriasis. The corresponding values for anterior chamber volume were as follows: 88.2±13.7mm(3) before PI, undilated; 106.3±18.8 before PI, dilated; 99.0±14.6 after PI, undilated, and 107.4±16.5 after PI, dilated (P<0.001). This study showed no change in the ocular biometric and anterior chamber parameters including iridocorneal angle after PI and/or pharmacologic mydriasis except for increments in anterior chamber volume. This factor has the potential to be used as a numerical proxy for iris position in evaluating and monitoring patients with primary angle closure suspects after PI. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Dilation x-ray imager a new∕faster gated x-ray imager for the NIF.

PubMed

Nagel, S R; Hilsabeck, T J; Bell, P M; Bradley, D K; Ayers, M J; Barrios, M A; Felker, B; Smith, R F; Collins, G W; Jones, O S; Kilkenny, J D; Chung, T; Piston, K; Raman, K S; Sammuli, B; Hares, J D; Dymoke-Bradshaw, A K L

2012-10-01

As the yield on implosion shots increases it is expected that the peak x-ray emission reduces to a duration with a FWHM as short as 20 ps for ∼7 × 10(18) neutron yield. However, the temporal resolution of currently used gated x-ray imagers on the NIF is 40-100 ps. We discuss the benefits of the higher temporal resolution for the NIF and present performance measurements for dilation x-ray imager, which utilizes pulse-dilation technology [T. J. Hilsabeck et al., Rev. Sci. Instrum. 81, 10E317 (2010)] to achieve x-ray imaging with temporal gate times below 10 ps. The measurements were conducted using the COMET laser, which is part of the Jupiter Laser Facility at the Lawrence Livermore National Laboratory.

Antarctic Analog for Dilational Bands on Europa

NASA Technical Reports Server (NTRS)

Hurford, T. A.; Brunt, K. M.

2014-01-01

Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Son, Christina H.; Law, Ethel; Oh, Jung Hun

Purpose: Although vaginal stenosis (VS) is a recognized toxicity in women who receive pelvic radiation therapy (RT), the relationship between RT dose and the volume and extent of toxicity has not been analyzed. We modeled this relationship to identify predictors of VS. Methods and Materials: We evaluated 54 women, aged 29 to 78 years, who underwent pelvic RT for rectal or anal cancer during 2008 to 2011 and were enrolled in a prospective study evaluating vaginal dilator use. Maximum dilator size was measured before RT (baseline) and 1 month and 12 months after RT. Dilator use was initiated at 1 month. The difference (D)more » in dilator size before and after RT was recorded. Those with D ≤−1 were classified as having VS (n=35); those with D ≥0 were classified as having no VS (n=19 at 1 month). Dose-volume parameters were extracted, and the generalized equivalent uniform dose (gEUD) was used to build a predictive model. Results: The mean vaginal doses were 50.0 Gy and 36.8 Gy for anal and rectal cancer patients, respectively. One month after RT, a gEUD model using a wide range of a values suggests that sparing of vaginal volume to a low dose may be important. When gEUD (a = −1) was <35 Gy and the mean vaginal dose was <43 Gy, severe VS was reduced (P=.02). A 1-year analysis suggests increasingly negative D values with increasing mean dose. However, patients with compliance <40% were more likely to have toxicity. Conclusions: Vaginal stenosis is influenced by multiple RT dose-volume characteristics. Mean dose and gEUD constraints together may reduce the risk of severe VS. Patients receiving higher mean vaginal doses should have greater compliance with dilator therapy to minimize risk of toxicity. Further validation with independent datasets is needed.« less

Sorption Behavior of Compressed CO2 and CH4 on Ultrathin Hybrid Poly(POSS-imide) Layers.

PubMed

Raaijmakers, Michiel J T; Ogieglo, Wojciech; Wiese, Martin; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck E

2015-12-09

Sorption of compressed gases into thin polymeric films is essential for applications including gas sensors and membrane based gas separation. For glassy polymers, the sorption behavior is dependent on the nonequilibrium status of the polymer. The uptake of molecules by a polymer is generally accompanied by dilation, or swelling, of the polymer material. In turn, this dilation can result in penetrant induced plasticization and physical aging that affect the nonequilibrium status of the polymer. Here, we investigate the dilation and sorption behavior of ultrathin membrane layers of a hybrid inorganic-organic network material that consists of alternating polyhedral oligomeric silsesquioxane and imide groups, upon exposure to compressed carbon dioxide and methane. The imide precursor contains fluoroalkene groups that provide affinity toward carbon dioxide, while the octa-functionalized silsesquioxane provides a high degree of cross-linking. This combination allows for extremely high sorption capacities, while structural rearrangements of the network are hindered. We study the simultaneous uptake of gases and dilation of the thin films at high pressures using spectroscopic ellipsometry measurements. Ellipsometry provides the changes in both the refractive index and the film thickness, and allows for accurate quantification of sorption and swelling. In contrast, gravimetric and volumetric measurements only provide a single parameter; this does not allow an accurate correction for, for instance, the changes in buoyancy because of the extensive geometrical changes of highly swelling films. The sorption behavior of the ultrathin hybrid layers depends on the fluoroalkene group content. At low pressure, the apparent molar volume of the gases is low compared to the liquid molar volume of carbon dioxide and methane, respectively. At high gas concentrations in the polymer film, the apparent molar volume of carbon dioxide and methane exceeds that of the liquid molar volume, and approaches that of the gas phase. The high sorption capacity and reversible dilation characteristics of the presented materials provide new directions for applications including gas sensors and gas separation membranes.

Eosinophilic esophagitis: dilate or medicate? A cost analysis model of the choice of initial therapy.

PubMed

Kavitt, R T; Penson, D F; Vaezi, M F

2014-07-01

Eosinophilic esophagitis (EoE) is an increasingly recognized clinical entity. The optimal initial treatment strategy in adults with EoE remains controversial. The aim of this study was to employ a decision analysis model to determine the less costly option between the two most commonly employed treatment strategies in EoE. We constructed a model for an index case of a patient with biopsy-proven EoE who continues to be symptomatic despite proton-pump inhibitor therapy. The following treatment strategies were included: (i) swallowed fluticasone inhaler (followed by esophagogastroduodenoscopy [EGD] with dilation if ineffective); and (ii) EGD with dilation (followed by swallowed fluticasone inhaler if ineffective). The time horizon was 1 year. The model focused on cost analysis of initial treatment strategies. The perspective of the healthcare payer was used. Sensitivity analyses were performed to assess the robustness of the model. For every patient whose symptoms improved or resolved with the strategy of fluticasone first followed by EGD, if necessary, it cost an average of $1078. Similarly, it cost an average of $1171 per patient if EGD with dilation was employed first. Sensitivity analyses indicated that initial treatment with fluticasone was the less costly strategy to improve dysphagia symptoms as long as the effectiveness of fluticasone remains at or above 0.62. Swallowed fluticasone inhaler (followed by EGD with dilation if necessary) is the more economical initial strategy when compared with EGD with dilation first. © 2012 Copyright the Authors. Journal compilation © 2012, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

A numerical framework for studying the biomechanical behavior of abdominal aortic aneurysm

NASA Astrophysics Data System (ADS)

Jalalahmadi, Golnaz; Linte, Cristian; Helguera, María.

2017-03-01

Abdominal aortic aneurysm (AAA) is known as a leading cause of death in the United States. AAA is an abnormal dilation of the aorta, which usually occurs below the renal arteries and causes an expansion at least 1.5 times its normal diameter. It has been shown that biomechanical parameters of the aortic tissue coupled with a set of specific geometric parameters characterizing the vessel expansion, affect the risk of aneurysm rupture. Here, we developed a numerical framework that incorporates both biomechanical and geometrical factors to study the behavior of abdominal aortic aneurysm. Our workflow enables the extraction of the aneurysm geometry from both clinical quality, as well as low-resolution MR images. We used a two-parameter, hyper-elastic, isotropic, incompressible material to model the vessel tissue. Our numerical model was tested using both synthetic and mouse data and we evaluated the effects of the geometrical and biomechanical properties on the developed peak wall stress. In addition, we performed several parameter sensitivity studies to investigate the effect of different factors affecting the AAA and its behavior and rupture. Lastly, relationships between different geometrical and biomechanical parameters and peak wall stress were determined. These studies help us better understand vessel tissue response to various loading, geometry and biomechanics conditions, and we plan to further correlate these findings with the pathophysiological conditions from a patient population diagnosed with abdominal aortic aneurysms.

The role of bulk viscosity on the decay of compressible, homogeneous, isotropic turbulence

NASA Astrophysics Data System (ADS)

Johnsen, Eric; Pan, Shaowu

2016-11-01

The practice of neglecting bulk viscosity in studies of compressible turbulence is widespread. While exact for monatomic gases and unlikely to strongly affect the dynamics of fluids whose bulk-to-shear viscosity ratio is small and/or of weakly compressible turbulence, this assumption is not justifiable for compressible, turbulent flows of gases whose bulk viscosity is orders of magnitude larger than their shear viscosities (e.g., CO2). To understand the mechanisms by which bulk viscosity and the associated phenomena affect compressible turbulence, we conduct DNS of freely decaying compressible, homogeneous, isotropic turbulence for ratios of bulk-to-shear viscosity ranging from 0-1000. Our simulations demonstrate that bulk viscosity increases the decay rate of turbulent kinetic energy; while enstrophy exhibits little sensitivity to bulk viscosity, dilatation is reduced by an order of magnitude within the two eddy turnover time. Via a Helmholtz decomposition of the flow, we determined that bulk viscosity damps the dilatational velocity and reduces dilatational-solenoidal exchanges, as well as pressure-dilatation coupling. In short, bulk viscosity renders compressible turbulence incompressible by reducing energy transfer between translational and internal modes.

Balloon dilation and intralesional steroid for benign rectal stricture management in a cat.

PubMed

Chavkin, Jessica A; Spector, Donna J; Stanley, Skye W

2010-08-01

A 4-year-old castrated male domestic shorthair presented for 1 week of constipation and tenesmus. A rectal stricture had been diagnosed 8 months prior at the time of adoption and the cat had been successfully managed with stool softeners until presentation. A complete diagnostic work-up failed to reveal an underlying etiology for the stricture and colonoscopy was performed. Endoscopic biopsies of the stricture revealed benign non-specific inflammatory changes. Balloon dilation of the rectal stricture was performed during the initial colonoscopy and 3 and 9 days later. Triamcinolone acetonide was injected into the stricture site with endoscopic guidance during the third dilation procedure. The patient has been monitored for over 27 months; follow-up indicates no signs of tenesmus and repeated rectal examinations reveal no stricture recurrence. This case report demonstrates that endoscopic balloon dilation with intralesional steroid injection represented a minimally invasive and effective option for the treatment of a benign rectal stricture in this cat, and deserves further prospective investigation. Copyright 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

Two-Rockets Thought Experiment

NASA Astrophysics Data System (ADS)

Smarandache, Florentin

2014-03-01

Let n>=2 be identical rockets: R1 ,R2 , ..., Rn. Each of them moving at constant different velocities respectively v1, v2, ..., vn on parallel directions in the same sense. In each rocket there is a light clock, the observer on earth also has a light clock. All n + 1 light clocks are identical and synchronized. The proper time Δt' in each rocket is the same. Let's focus on two arbitrary rockets Ri and Rjfrom the previous n rockets. Let's suppose, without loss of generality, that their speeds verify vi

Some Pitfalls in Special Relativity

ERIC Educational Resources Information Center

Chai, An-Ti

1973-01-01

The problem of observing a collision between two spaceships is utilized to illustrate the misuse of time dilation and length contraction, and the incorrect description of space-time coordinates in special relativity. (Author/DF)

Mechanism of thrombin-induced vasodilation in human coronary arterioles.

PubMed

Bosnjak, John J; Terata, Ken; Miura, Hiroto; Sato, Atsushi; Nicolosi, Alfred C; McDonald, Monica; Manthei, Sara A; Saito, Takashi; Hatoum, Ossama A; Gutterman, David D

2003-04-01

Thrombin (Thromb), activated as part of the clotting cascade, dilates conduit arteries through an endothelial pertussis toxin (PTX)-sensitive G-protein receptor and releases nitric oxide (NO). Thromb also acts on downstream microvessels. Therefore, we examined whether Thromb dilates human coronary arterioles (HCA). HCA from right atrial appendages were constricted by 30-50% with endothelin-1. Dilation to Thromb (10(-4)-1 U/ml) was assessed before and after inhibitors with videomicroscopy. There was no tachyphylaxis to Thromb dilation (maximum dilation = 87.0%, ED(50) = 1.49 x 10(-2)). Dilation to Thromb was abolished with either hirudin or denudation but was not affected by PTX. Neither N(omega)-nitro-l-arginine methyl ester (n = 7), indomethacin (n = 9), (1)H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (n = 6), tetraethylammonium chloride (n = 5), nor iberiotoxin (n = 4) reduced dilation to Thromb. However, KCl (maximum dilation = 89 +/- 5 vs. 20 +/- 10%; P < 0.05; n = 7), tetrabutylammonium chloride (maximum dilation = 79 +/- 7 vs. 21 +/- 4%; P < 0.05; n = 5), and charybdotoxin (maximum dilation = 89 +/- 4 vs. 10 +/- 2%; P < 0.05; n = 4) attenuated dilation to Thromb. In contrast to animal models, Thromb-induced dilation in human arterioles is independent of G(i)-protein activation and NO release. However, Thromb dilation is endothelium dependent, is maintained on consecutive applications, and involves activation of K(+) channels. We speculate that an endothelium-derived hyperpolarizing factor contributes to Thromb-induced dilation in HCA.

Choledochoscopic high-frequency needle-knife electrotomy for treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy.

PubMed

Yang, Yu-Long; Zhang, Cheng; Wu, Ping; Ma, Yue-Feng; Li, Jing-Yi; Zhang, Hong-Wei; Shi, Li-Jun; Lin, Mei-Ju; Yu, Ying

2016-05-06

Anastomotic stricture is a complex and substantial complication following Roux-en-Y hepaticojejunostomy. Initially, endoscopic and percutaneous approaches are often attempted, but the gold standard remains surgical biliary reconstruction, especially for refractory stricture. However, this solution leaves much room for improvement, due to the challenging nature of the biliary reconstruction procedure, in which anastomotic stricture may still occur. To investigate the feasibility and effectiveness of choledochoscopic high-frequency needle-knife electrotomy as an intervention in the treatment of anastomotic strictures following Roux-en-Y hepaticojejunostomy. From February 2010 to October 2014, clinical data was collected and retrospectively compared for patients who underwent balloon dilation or/and choledochoscopic high-frequency needle-knife electrotomy for the treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy. A total of 38 patients underwent successful choledochoscopic treatment and all the anastomotic strictures were removed successfully, 19 of which were treated with electrotomy, 7 with balloon dilation, and 12 with both electrotomy and balloon dilation. Among these groups,the average operating times were 6.9 ± 2.4 min,10.1 ± 6.8 min, and 20.2 ± 13.5 min, respectively. The average stent supporting times were 6.3 ± 0.7 months, 6.5 ± 0.6 months, and 6.1 ± 0.4 respectively. The mean follow-up after stent removal was 42.1 ± 27.4 months, and in 26.3 % (5/19), 28.5 % (2/7) and 16.7 % (2/12) of cases, recurrent anastomotic stricture occurred. Of these 9 total patients with recurrent anastomotic, two patients were successfully rescued by full-covered self-expanding removable metal stents and 7 patients by electrotomy combined with balloon dilation. Choledochoscopic high-frequency needle-knife electrotomy is both feasible and safe in the treatment of anastomotic stricture after Roux-en-Y hepaticojejunostomy, with a similar long-term outcome to balloon dilation in treating anastomotic stricture after Roux-en-Y hepaticojejunostomy. A combination of choledochoscopic electrotomy concurrent with balloon dilation should be recommended based on the low rate of recurrence.

A new clinical method for the assessment of penile endothelial function using the flow mediated dilation with plethysmography technique.

PubMed

Dayan, Lior; Greunwald, Illan; Vardi, Yoram; Jacob, Giris

2005-04-01

Penile endothelial function (EnF) is 1 of the major factors involved in the pathophysiology of erectile dysfunction. EnF assessment could offer crucial information on the etiology and degree of severity of cavernosal vascular pathology. In the present study we propose a new technique for the evaluation of penile EnF and test its applicability using strain gauge plethysmography. A total of 23 healthy subjects (13 younger and 10 older than 40 years) with no history of erectile dysfunction were studied. The flow mediated dilation technique was applied to the arm and penis in both age groups for the assessment of EnF. Baseline blood flow and the sequential flow recordings after rapid cessation of 5 minutes of ischemia were obtained in both organs. Baseline flow in the penis was significantly higher (approximately 3-fold) than that in the forearm and was not affected by age in either organ. Both measures of penile EnF, ie area under the flow-time curve (AUC) and maximal flow obtained after ischemia were significantly lower in the older group compared to the younger group (p <0.01 and p <0.02, respectively). Individual penile AUC and maximal flow were significantly correlated with age (r = 0.55, p <0.01 and r = 0.50, p <0.02, respectively). Finally a positive, significant correlation existed between penile and forearm AUC (p <0.05, r = 0.48). The implementation of the flow mediated dilation technique using mercury strain gauge plethysmography is simple and applicable for the assessment of penile EnF. Endothelial function parameters in the penis were found to correlate with those in the forearm, thus support for the validity of the technique is given. Further strength for the validity of this procedure in the penis comes from the comparison between the forearm and penis, and the relation to subject age.

Dilated intercellular space diameter as marker of reflux-related mucosal injury in children with chronic cough and gastro-oesophageal reflux disease.

PubMed

Borrelli, O; Mancini, V; Thapar, N; Ribolsi, M; Emerenziani, S; de'Angelis, G; Bizzarri, B; Lindley, K J; Cicala, M

2014-04-01

The diagnostic corroboration of the relationship between gastro-oesophageal reflux disease (GERD) and chronic cough remains challenging. To compare oesophageal mucosal intercellular space diameter (ISD) in children with GERD, children with gastro-oesophageal reflux (GER)-related cough (GrC) and a control group, and to explore the relationship between baseline impedance levels and dilated ISD in children with GER-related cough. Forty children with GERD, 15 children with GrC and 12 controls prospectively underwent oesophagogastroduodenoscopy (EGD) with oesophageal biopsies taken 2-3 cm above squamocolumnar junction. ISD were quantified using transmission electron microscopy. Impedance-pH monitoring with evaluation of baseline impedance in the most distal impedance channel was performed in both patient groups. A significant difference in mean ISD values was found between GrC patients (0.9 ± 0.2 μm) and controls (0.5 ± 0.2 μm, P < 0.001), whereas there was no difference between GrC and GERD group (1 ± 0.3 μm, NS). No difference was found in the mean ISD between GrC children with or without pathological oesophageal acid exposure time (1 ± 0.3 vs. 0.9 ± 0.2 μm), and there was no correlation between ISD and any reflux parameter. Finally, there was no correlation between ISD and distal baseline impedance values (r:-0.35; NS). In children with reflux-related cough, dilated intercellular space diameter appears to be an objective and useful marker of oesophageal mucosal injury regardless of acid exposure, and its evaluation should be considered for those patients where the diagnosis is uncertain. In children with reflux-related cough, baseline impedance levels have no role in identifying reflux-induced oesophageal mucosal ultrastructural changes. © 2014 John Wiley & Sons Ltd.

Mechanisms of flow and ACh-induced dilation in rat soleus arterioles are altered by hindlimb unweighting

NASA Technical Reports Server (NTRS)

Schrage, William G.; Woodman, Christopher R.; Laughlin, M. Harold

2002-01-01

The purpose of this study was to test the hypothesis that endothelium-dependent dilation (flow-induced dilation and ACh-induced dilation) in rat soleus muscle arterioles is impaired by hindlimb unweighting (HLU). Male Sprague-Dawley rats (approximately 300 g) were exposed to HLU or weight-bearing control (Con) conditions for 14 days. Soleus first-order (1A) and second-order (2A) arterioles were isolated, cannulated, and exposed to step increases in luminal flow at constant pressure. Flow-induced dilation was not impaired by HLU in 1A or 2A arterioles. The cyclooxygenase inhibitor indomethacin (Indo; 50 microM) did not alter flow-induced dilation in 1As or 2As. Inhibition of nitric oxide synthase (NOS) with N(omega)-nitro-L-arginine (L-NNA; 300 microM) reduced flow-induced dilation by 65-70% in Con and HLU 1As. In contrast, L-NNA abolished flow-induced dilation in 2As from Con rats but had no effect in HLU 2As. Combined treatment with L-NNA + Indo reduced tone in 1As and 2As from Con rats, but flow-induced dilation in the presence of L-NNA + Indo was not different from responses without inhibitors in either Con or HLU 1As or 2As. HLU also did not impair ACh-induced dilation (10(-9)-10(-4) M) in soleus 2As. L-NNA reduced ACh-induced dilation by approximately 40% in Con 2As but abolished dilation in HLU 2As. Indo did not alter ACh-induced dilation in Con or HLU 2As, whereas combined treatment with L-NNA + Indo abolished ACh-induced dilation in 2As from both groups. We conclude that flow-induced dilation (1As and 2As) was preserved after 2 wk HLU, but HLU decreased the contribution of NOS in mediating flow-induced dilation and increased the contribution of a NOS- and cyclooxygenase-independent mechanism (possibly endothelium-derived hyperpolarizing factor). In soleus 2As, ACh-induced dilation was preserved after 2-wk HLU but the contribution of NOS in mediating ACh-induced dilation was increased.

A review of techniques of induced abortion.

PubMed

Hepburn, S

1981-04-01

Various techniques are available for inducing abortion. Evacuation of the uterus through the vagina is generally the preferred method in first trimester pregnancies. Dilation of the cervical canal by inserting rod dilators or laminaria tents allows the withdrawal of the fetus. Suction procedures (vacuum aspiration, uterine aspiration, or suction curettage) are possible since the decidua are separable from the basal layer of endometrium. This removal by force does not damage other maternal tissue. A cannula is introduced into the uterine cavity through the dilated cervix and its operator is then connected to a pump by way of a flexible tube which delivers negative pressure of about 600 mm of mercury. When the fetus is withdrawn, the uterus is felt to contract onto the cannula. The average time for this procedure is 5 minutes. Surgical curettage or dilatation and evacuation first dilates the cervical canal and then removes fetal parts and tissue from ovum forceps; a sharp curette does the rest. Anesthesia for these procedures may be general, local, or spinal. The techniques of menstrual regulation is used before pregnancy can be confirmed. However with the advent of the RIA test for the beta subunit of HCG this procedure is rarely indicated. Induction of premature labor is used in the later 1/2 of the second trimester and utilizes prostaglandins. Intraamniobor usually begins within 24 hours. Hysterotomy and hysterectomy are surgical procedures used in abortions.

[Approach to percutaneous nephrolithotomy. Comparison of the procedure in a one-shot versus the sequential with metal dilata].

PubMed

Sedano-Portillo, Ismael; Ochoa-León, Gastón; Fuentes-Orozco, Clotilde; Irusteta-Jiménez, Leire; Michel-Espinoza, Luis Rodrigo; Salazar-Parra, Marcela; Cuesta-Márquez, Lizbeth; González-Ojeda, Alejandro

2017-01-01

Percutaneous nephrolithotomy is an efficient approach for treatment of different types of kidney stones. Various types of access techniques have been described like sequential dilatation and one-shot procedure. To determine the differences in time of exposure to X-rays and hemoglobin levels between techniques. Controlled clinical trial. Patients older than 18 years with complex/uncomplicated kidney stones, without urine infection were included. They were assigned randomly to one of the two techniques. Response variables were determined before and 24 h after procedures. 59 patients were included: 30 underwent one-shot procedure (study-group) and 29 sequential dilatation (control-group). Baseline characteristics were similar. Study group had a lower postoperative hemoglobin decline than control group (0.81 vs. 2.03 g/dl, respectively; p < 0.001); X-ray exposure time (69.6 vs. 100.62 s; p < 0.001) and postoperative creatinine serum levels (0.93 ± 0.29 vs. 1.13 ± 0.4 mg/dl; p = 0.039). No significant differences in postoperative morbidity were found. One-shot technique demonstrated better results compared to sequential dilatation.

Effect of metoprolol on the beta-adrenoceptor density of lymphocytes in patients with dilated cardiomyopathy.

PubMed

Ishida, S; Makino, N; Masutomo, K; Hata, T; Yanaga, T

1993-05-01

We investigated the effect of the beta 1-selective blocker metoprolol on the beta-adrenergic receptor density of circulating lymphocytes in patients with dilated cardiomyopathy. Nine men in New York Heart Association functional classes II (six patients) and III were given metoprolol for 6 months (mean dose 45.6 +/- 18.1 mg). Their cardiac function was assessed by echocardiography. Although there was no difference in the heart rate or pressure rate products, the end-systolic and end-diastolic dimensions significantly decreased in six patients after metoprolol treatment. The ejection fraction, fractional shortening, and mean left ventricular circumferential shortening were significantly increased after the treatment. beta-Adrenoceptor densities of lymphocytes, examined by iodine 125-labeled iodocyanopindolol, were reduced in patients at entry but recovered to normal levels after the metoprolol treatment. The dissociation constants did not differ at any stage of the disease. The relationship between beta-adrenoceptor densities in lymphocytes and echocardiographic parameters showed a positive correlation with the plasma norepinephrine concentration. This study thus provides evidence that long-term metoprolol therapy for dilated cardiomyopathy is associated with beta-receptor up-regulation, and the restoration of myocardial beta-receptor density may be associated with the improved cardiac function as determined by echocardiography.

High Bandwidth, Fine Resolution Deformable Mirror Design.

DTIC Science & Technology

1980-03-01

Low Temperature Solders 68 B.6 Influence Function Parameters 68 APPENDIX C 19 Capacitance Measurement 69 ACCESSION for NTIS white Sectloo ODC Buff...Multilayer actuator: Dilatation versus applied electric field 10 Figure 3 - Multilayer actuator: Influence function 11 Figure 4 - Honeycomb device...bimorph 20 Figure 8 - Bimorph device: Influence function of a bimorph device which has a glass plate 0.20 cm thick 24 Figure 9 - Bimorph device

The Kovdor-2015 experiment: study of the parameters of a conductive layer of dilatancy-diffusion nature (DD Layer) in the Archaean crystalline basement of the Baltic Shield

NASA Astrophysics Data System (ADS)

Zhamaletdinov, A. A.; Velikhov, E. P.; Shevtsov, A. N.; Kolobov, V. V.; Kolesnikov, V. E.; Skorokhodov, A. A.; Korotkova, T. G.; Ivonin, V. V.; Ryazantsev, P. A.; Birulya, M. A.

2017-06-01

This paper addresses the Kovdor-2015 Experiment involving frequency electromagnetic soundings of the Archaean basement of the Earth's crust in the southwestern part of the Kola Peninsula. Eleven soundings were carried out using two transmitting arrangements, 85 km apart. Each arrangement consisted of two mutually orthogonal grounded electric dipoles of 1.5 km long. The distances between the source and the receiver were 25 and 50 km. Interpretation of the results took into account the influence of displacement currents and static distortions. It is found that there is an intermediate conductive layer of the dilatancy-diffusion nature (DD layer) with a longitudinal conductivity of about one siemens at depths ranging from 1.5-2 to 5-7 km. The results are interpreted in the terms of geodynamics.

Machine Learning to Differentiate Between Positive and Negative Emotions Using Pupil Diameter

PubMed Central

Babiker, Areej; Faye, Ibrahima; Prehn, Kristin; Malik, Aamir

2015-01-01

Pupil diameter (PD) has been suggested as a reliable parameter for identifying an individual’s emotional state. In this paper, we introduce a learning machine technique to detect and differentiate between positive and negative emotions. We presented 30 participants with positive and negative sound stimuli and recorded pupillary responses. The results showed a significant increase in pupil dilation during the processing of negative and positive sound stimuli with greater increase for negative stimuli. We also found a more sustained dilation for negative compared to positive stimuli at the end of the trial, which was utilized to differentiate between positive and negative emotions using a machine learning approach which gave an accuracy of 96.5% with sensitivity of 97.93% and specificity of 98%. The obtained results were validated using another dataset designed for a different study and which was recorded while 30 participants processed word pairs with positive and negative emotions. PMID:26733912

Eyeing up the Future of the Pupillary Light Reflex in Neurodiagnostics

PubMed Central

Hall, Charlotte A.; Chilcott, Robert P.

2018-01-01

The pupillary light reflex (PLR) describes the constriction and subsequent dilation of the pupil in response to light as a result of the antagonistic actions of the iris sphincter and dilator muscles. Since these muscles are innervated by the parasympathetic and sympathetic nervous systems, respectively, different parameters of the PLR can be used as indicators for either sympathetic or parasympathetic modulation. Thus, the PLR provides an important metric of autonomic nervous system function that has been exploited for a wide range of clinical applications. Measurement of the PLR using dynamic pupillometry is now an established quantitative, non-invasive tool in assessment of traumatic head injuries. This review examines the more recent application of dynamic pupillometry as a diagnostic tool for a wide range of clinical conditions, varying from neurodegenerative disease to exposure to toxic chemicals, as well as its potential in the non-invasive diagnosis of infectious disease. PMID:29534018

Clinical evaluation of Apamarga-Ksharataila Uttarabasti in the management of urethral stricture

PubMed Central

Reddy, K. Rajeshwar

2013-01-01

Stricture urethra, though a rare condition, still is a rational and troublesome problem in the international society. Major complications caused by this disease are obstructed urine flow, urine stasis leading to urinary tract infection, calculi formation, etc. This condition can be correlated with Mutramarga Sankocha in Ayurveda. Modern medical science suggests urethral dilatation, which may cause bleeding, false passage and fistula formation in few cases. Surgical procedures have their own complications and limitations. Uttarabasti, a para-surgical procedure is the most effective available treatment in Ayurveda for the diseases of Mutravaha Strotas. In the present study, total 60 patients of urethral stricture were divided into two groups and treated with Uttarabasti (Group A) and urethral dilatation (Group B). The symptoms like obstructed urine flow, straining, dribbling and prolongation of micturation were assessed before and after treatment. The results of the study were significant on all the parameters. PMID:24250127

Clinical evaluation of Apamarga-Ksharataila Uttarabasti in the management of urethral stricture.

PubMed

Reddy, K Rajeshwar

2013-04-01

Stricture urethra, though a rare condition, still is a rational and troublesome problem in the international society. Major complications caused by this disease are obstructed urine flow, urine stasis leading to urinary tract infection, calculi formation, etc. This condition can be correlated with Mutramarga Sankocha in Ayurveda. Modern medical science suggests urethral dilatation, which may cause bleeding, false passage and fistula formation in few cases. Surgical procedures have their own complications and limitations. Uttarabasti, a para-surgical procedure is the most effective available treatment in Ayurveda for the diseases of Mutravaha Strotas. In the present study, total 60 patients of urethral stricture were divided into two groups and treated with Uttarabasti (Group A) and urethral dilatation (Group B). The symptoms like obstructed urine flow, straining, dribbling and prolongation of micturation were assessed before and after treatment. The results of the study were significant on all the parameters.

Ventricular dilation and electrical dyssynchrony synergistically increase regional mechanical nonuniformity but not mechanical dyssynchrony: a computational model.

PubMed

Kerckhoffs, Roy C P; Omens, Jeffrey H; McCulloch, Andrew D; Mulligan, Lawrence J

2010-07-01

Heart failure (HF) in combination with mechanical dyssynchrony is associated with a high mortality rate. To quantify contractile dysfunction in patients with HF, investigators have proposed several indices of mechanical dyssynchrony, including percentile range of time to peak shortening (WTpeak), circumferential uniformity ratio estimate (CURE), and internal stretch fraction (ISF). The goal of this study was to compare the sensitivity of these indices to 4 major abnormalities responsible for cardiac dysfunction in dyssynchronous HF: dilation, negative inotropy, negative lusitropy, and dyssynchronous activation. All combinations of these 4 major abnormalities were included in 3D computational models of ventricular electromechanics. Compared with a nonfailing heart model, ventricles were dilated, inotropy was reduced, twitch duration was prolonged, and activation sequence was changed from normal to left bundle branch block. In the nonfailing heart, CURE, ISF, and WTpeak were 0.97+/-0.004, 0.010+/-0.002, and 78+/-1 milliseconds, respectively. With dilation alone, CURE decreased 2.0+/-0.07%, ISF increased 58+/-47%, and WTpeak increased 31+/-3%. With dyssynchronous activation alone, CURE decreased 15+/-0.6%, ISF increased 14-fold (+/-3), and WTpeak increased 121+/-4%. With the combination of dilation and dyssynchronous activation, CURE decreased 23+/-0.8%, ISF increased 20-fold (+/-5), and WTpeak increased 147+/-5%. Dilation and left bundle branch block combined synergistically decreased regional cardiac function. CURE and ISF were sensitive to this combination, but WTpeak was not. CURE and ISF also reflected the relative nonuniform distribution of regional work better than WTpeak. These findings might explain why CURE and ISF are better predictors of reverse remodeling in cardiac resynchronization therapy.

Pathogenesis of aortic dilatation in mucopolysaccharidosis VII mice may involve complement activation

PubMed Central

Baldo, Guilherme; Wu, Susan; Howe, Ruth A.; Ramamoothy, Meera; Knutsen, Russell H.; Fang, Jiali; Mecham, Robert P.; Liu, Yuli; Wu, Xiaobo; Atkinson, John P.; Ponder, Katherine P.

2012-01-01

Mucopolysaccharidosis VII (MPS VII) is due to mutations within the gene encoding the lysosomal enzyme β-glucuronidase, and results in the accumulation of glycosaminoglycans. MPS VII causes aortic dilatation and elastin fragmentation, which is associated with upregulation of the elastases cathepsin S (CtsS) and matrix metalloproteinase 12 (MMP12). To test the role of these enzymes, MPS VII mice were crossed with mice deficient in CtsS or MMP12, and the effect upon aortic dilatation was determined. CtsS deficiency did not protect against aortic dilatation in MPS VII mice, but also failed to prevent an upregulation of cathepsin enzyme activity. Further analysis with substrates and inhibitors specific for particular cathepsins suggests that this enzyme activity was due to CtsB, which could contribute to elastin fragmentation. Similarly, MMP12 deficiency and deficiency of both MMP12 and CtsS could not prevent aortic dilatation in MPS VII mice. Microarray and reverse-transcriptase real-time PCR were performed to look for upregulation of other elastases. This demonstrated that mRNA for complement component D was elevated in MPS VII mice, while immunostaining demonstrated high levels of complement component C3 on surfaces within the aortic media. Finally, we demonstrate that neonatal intravenous injection of a retroviral vector encoding β-glucuronidase reduced aortic dilatation. We conclude that neither CtsS nor MMP12 are necessary for elastin fragmentation in MPS VII mouse aorta, and propose that CtsB and/or complement component D may be involved. Complement may be activated by the GAGs that accumulate, and may play a role in signal transduction pathways that upregulate elastases. PMID:21944884

Early endoscopic balloon dilation in caustic-induced gastric injury.

PubMed

Kochhar, Rakesh; Poornachandra, Kuchhangi Sureshchandra; Dutta, Usha; Agrawal, Amit; Singh, Kartar

2010-04-01

There are no reports on endoscopic balloon dilation (EBD) for caustic-induced gastric outlet obstruction (GOO) in the acute or subacute phase. To study the efficacy of early EBD in patients with caustic-induced gastric injury. Tertiary care center in India. Retrospective analysis of data. Out of 41 patients with caustic-induced GOO who reported to us in the subacute phase between January 2001 and December 2008, 31 were treated by EBD. All 31 had ingested an acid 14.39 +/- 4.65 days earlier. EBD was achieved by using wire-guided balloons under endoscopic guidance. The balloon was negotiated across the narrowed segment and inflated for 60 seconds using a pressure gun. Balloons of incremental diameter, up to a maximum of 3 sizes, were used in each sitting. Procedural success was defined as reaching the end point of dilation (15 mm) and absence of symptoms. All 31 patients (18 male, mean age 32.06 +/- 11.04 years) could be successfully dilated. All but 1 underwent successful dilations to achieve the end point of 15 mm, requiring a median of 9 (range 3-18) dilations over a period of 7 (range 1.5-16) weeks. Complications included self-limiting pain (n = 10), bleeding at the time of the procedure (n = 9), and perforation in 1 patient (3.2%) who required surgery. Thirty patients were followed up for a median of 21 (range 3-72) months with no recurrence. Early EBD by an expert endoscopist is a safe and effective treatment modality in the management of caustic-induced GOO. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

A quantitative model of application slow-down in multi-resource shared systems

DOE PAGES

Lim, Seung-Hwan; Kim, Youngjae

2016-12-26

Scheduling multiple jobs onto a platform enhances system utilization by sharing resources. The benefits from higher resource utilization include reduced cost to construct, operate, and maintain a system, which often include energy consumption. Maximizing these benefits comes at a price-resource contention among jobs increases job completion time. In this study, we analyze slow-downs of jobs due to contention for multiple resources in a system; referred to as dilation factor. We observe that multiple-resource contention creates non-linear dilation factors of jobs. From this observation, we establish a general quantitative model for dilation factors of jobs in multi-resource systems. A job ismore » characterized by a vector-valued loading statistics and dilation factors of a job set are given by a quadratic function of their loading vectors. We demonstrate how to systematically characterize a job, maintain the data structure to calculate the dilation factor (loading matrix), and calculate the dilation factor of each job. We validate the accuracy of the model with multiple processes running on a native Linux server, virtualized servers, and with multiple MapReduce workloads co-scheduled in a cluster. Evaluation with measured data shows that the D-factor model has an error margin of less than 16%. We extended the D-factor model to capture the slow-down of applications when multiple identical resources exist such as multi-core environments and multi-disks environments. Finally, validation results of the extended D-factor model with HPC checkpoint applications on the parallel file systems show that D-factor accurately captures the slow down of concurrent applications in such environments.« less

Expectant management compared with physical examination-indicated cerclage (EM-PEC) in selected women with a dilated cervix at 14(0/7)-25(6/7) weeks: results from the EM-PEC international cohort study.

PubMed

Pereira, Leonardo; Cotter, Amanda; Gómez, Ricardo; Berghella, Vincenzo; Prasertcharoensuk, Witoon; Rasanen, Juha; Chaithongwongwatthana, Surasith; Mittal, Suneeta; Daly, Sean; Airoldi, Jim; Tolosa, Jorge E

2007-11-01

The objective of the study was to compare pregnancy outcomes in selected women with a dilated cervix who underwent expectant management or physical examination-indicated cerclage. This was a historical cohort study conducted by the Global Network for Perinatal and Reproductive Health. Women between 14(0/7) and 25(6/7) weeks' gestation with a dilated cervix were identified at 10 centers by ultrasound or digital examination. Primary outcome was time from presentation until delivery (weeks). Secondary outcomes were neonatal survival, birthweight greater than 1500 g and preterm birth less than 28 weeks. Multivariate regression was used to assess the likelihood of neonatal outcomes and control for confounders. Of 225 women, 152 received a physical examination-indicated cerclage, and 73 were managed expectantly without cerclage. Cervical dilation, gestational age at presentation, and antenatal steroid use differed between groups. In the adjusted analyses, cerclage was associated with longer interval from presentation until delivery, improved neonatal survival, birthweight greater than 1500 g and preterm birth less than 28 weeks, compared with expectant management. Similar results were obtained in the analyses limited to women dilated between 2 and 4 cm (n = 122). In this study, the largest cohort reported to date, physical examination-indicated cerclage appears to prolong gestation and improve neonatal survival, compared with expectant management in selected women with cervical dilation between 14(0/7) and 25(6/7) weeks. A randomized, controlled trial should be conducted to determine whether these potential benefits outweigh the risks of cerclage placement in this population.

A quantitative model of application slow-down in multi-resource shared systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Seung-Hwan; Kim, Youngjae

Scheduling multiple jobs onto a platform enhances system utilization by sharing resources. The benefits from higher resource utilization include reduced cost to construct, operate, and maintain a system, which often include energy consumption. Maximizing these benefits comes at a price-resource contention among jobs increases job completion time. In this study, we analyze slow-downs of jobs due to contention for multiple resources in a system; referred to as dilation factor. We observe that multiple-resource contention creates non-linear dilation factors of jobs. From this observation, we establish a general quantitative model for dilation factors of jobs in multi-resource systems. A job ismore » characterized by a vector-valued loading statistics and dilation factors of a job set are given by a quadratic function of their loading vectors. We demonstrate how to systematically characterize a job, maintain the data structure to calculate the dilation factor (loading matrix), and calculate the dilation factor of each job. We validate the accuracy of the model with multiple processes running on a native Linux server, virtualized servers, and with multiple MapReduce workloads co-scheduled in a cluster. Evaluation with measured data shows that the D-factor model has an error margin of less than 16%. We extended the D-factor model to capture the slow-down of applications when multiple identical resources exist such as multi-core environments and multi-disks environments. Finally, validation results of the extended D-factor model with HPC checkpoint applications on the parallel file systems show that D-factor accurately captures the slow down of concurrent applications in such environments.« less

Adult-like neuroelectrical response to inequity in children: Evidence from the ultimatum game.

PubMed

Rêgo, Gabriel Gaudencio; Campanhã, Camila; Kassab, Ana Paula; Romero, Ruth Lyra; Minati, Ludovico; Boggio, Paulo Sérgio

2016-01-01

People react aversely when faced with unfair situations, a phenomenon that has been related to an electroencephalographic (EEG) potential known as medial frontal negativity (MFN). To our knowledge, the existence of the MFN in children has not yet been demonstrated. Here, we recorded EEG activity from 15 children playing the ultimatum game (UG) and who afterward performed a recognition task, in order to assess whether they could recognize the unfair and fair (familiar) proposers among unfamiliar faces. During the recognition task, we also acquired pupil dilation data to investigate subconscious recognition processes. A typical (adult-like) MFN component was detected in reaction to unfair proposals. We found a positive correlation between reaction time and empathy, as well as a negative correlation between reaction time and systematic reasoning scores. Finally, we detected a significant difference in pupil dilation in response to unfamiliar faces versus UG proposers. Our data provide the first evidence of MFN in children, which appears to index similar neurophysiological phenomena as in adults. Also, reaction time to fair proposals seems to be related to individual traits, as represented by empathy and systematizing. Our pupil dilation data provide evidence that automatic responses to faces did not index fairness, but familiarity. These findings have implications for our understanding of social development in typically developing children.

Self-powered monitoring of repeated head impacts using time-dilation energy measurement circuit.

PubMed

Feng, Tao; Aono, Kenji; Covassin, Tracey; Chakrabartty, Shantanu

2015-04-01

Due to the current epidemic levels of sport-related concussions (SRC) in the U.S., there is a pressing need for technologies that can facilitate long-term and continuous monitoring of head impacts. Existing helmet-sensor technology is inconsistent, inaccurate, and is not economically or logistically practical for large-scale human studies. In this paper, we present the design of a miniature, battery-less, self-powered sensor that can be embedded inside sport helmets and can continuously monitor and store different spatial and temporal statistics of the helmet impacts. At the core of the proposed sensor is a novel time-dilation circuit that allows measurement of a wide-range of impact energies. In this paper an array of linear piezo-floating-gate (PFG) injectors has been used for self-powered sensing and storage of linear and rotational head-impact statistics. The stored statistics are then retrieved using a plug-and-play reader and has been used for offline data analysis. We report simulation and measurement results validating the functionality of the time-dilation circuit for different levels of impact energies. Also, using prototypes of linear PFG integrated circuits fabricated in a 0.5 μm CMOS process, we demonstrate the functionality of the proposed helmet-sensors using controlled drop tests.

The Enright phenomenon. Stereoscopic distortion of perceived driving speed induced by monocular pupil dilation.

PubMed

Carkeet, Andrew; Wood, Joanne M; McNeill, Kylie M; McNeill, Hamish J; James, Joanna A; Holder, Leigh S

The Enright phenomenon describes the distortion in speed perception experienced by an observer looking sideways from a moving vehicle when viewing with interocular differences in retinal image brightness, usually induced by neutral density filters. We investigated whether the Enright phenomenon could be induced with monocular pupil dilation using tropicamide. We tested 17 visually normal young adults on a closed road driving circuit. Participants were asked to travel at Goal Speeds of 40km/h and 60km/h while looking sideways from the vehicle with: (i) both eyes with undilated pupils; (ii) both eyes with dilated pupils; (iii) with the leading eye only dilated; and (iv) the trailing eye only dilated. For each condition we recorded actual driving speed. With the pupil of the leading eye dilated participants drove significantly faster (by an average of 3.8km/h) than with both eyes dilated (p=0.02); with the trailing eye dilated participants drove significantly slower (by an average of 3.2km/h) than with both eyes dilated (p<0.001). The speed, with the leading eye dilated, was faster by an average of 7km/h than with the trailing eye dilated (p<0.001). There was no significant difference between driving speeds when viewing with both eyes either dilated or undilated (p=0.322). Our results are the first to show a measurable change in driving behaviour following monocular pupil dilation and support predictions based on the Enright phenomenon. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

Predictors of short term treatment outcome in patients with achalasia following endoscopic or surgical therapy.

PubMed

Gheorghe, Cristian; Bancila, Ion; Tutuian, Radu; Iacob, Razvan; Tomulescu, Victor

2012-01-01

Pneumatic balloon dilation and surgical myotomy are the most effective treatments for achalasia. While there is controversy which method is best, the aim of the current study was to identify predictors of symptom recurrence after endoscopic or surgical therapy. Patients undergoing pneumatic balloon dilatation (30mm) or laparoscopic Heller myotomy with Dor fundoplication were included in the study. Analyzed parameters include total symptom score (sum of 0-5 point intensity for dysphagia, regurgitation and chest pain), width and height of esophageal column at 2 and 5 minutes after oral barium ingestion, lower esophageal sphincter (LES) length, resting (LESP) and residual pressure (LESRP) before and 3 months after intervention. Patients with symptoms score <3 at the 3-month follow-up visit were considered asymptomatic. Twenty-one patients underwent pneumatic dilation (14) or laparoscopic myotomy (7). Total symptom score improved (p<0.01) from pre- (7.2±2.7) to post-intervention (1.7±2.6). Eleven (85.8%) patients in the endoscopic group vs. 7 (100%) patients in the surgical group were symptom-free 3 months after intervention. Therapies improved LESP (24.4±8.2mmHg pre- vs. 15.4±10.3mmHg post-therapy; p=0.003) and mean LESRP (7.9±4.3mmHg pre- vs. 5.3±6.7mmHg post-therapy; p=0.03). Univariate linear regression analysis identified barium contrast column width >5cm at 2 minutes (p=0.04), LES length <2cm (p=0.003) and LESRP >10mmHg (p=0.02) as predictors for persistent symptoms. While >85% of achalasia patients responded well to 30mm pneumatic balloon dilation, patients with elevated LES pressure, short LES and wide esophagus should be considered as primary surgical candidates.

Value of the Electrocardiogram as a Predictor of Right Ventricular Dysfunction in Patients With Chronic Right Ventricular Volume Overload.

PubMed

Alonso, Pau; Andrés, Ana; Rueda, Joaquín; Buendía, Francisco; Igual, Begoña; Rodríguez, María; Osa, Ana; Arnau, Miguel A; Salvador, Antonio

2015-05-01

Pulmonary regurgitation is a common complication in patients with repaired tetralogy of Fallot or congenital pulmonary stenosis. Electrocardiographic variables have been correlated with parameters used to evaluate right ventricular function. We aimed to analyze the diagnostic value of the width and fragmentation of the electrocardiogram in the identification of patients with right ventricular dysfunction and/or dilation. We selected 107 consecutive patients diagnosed with severe pulmonary insufficiency after repair of pulmonary stenosis or tetralogy of Fallot. The tests included electrocardiography, echocardiography, and magnetic resonance. Each electrocardiogram was analyzed manually to measure QRS duration. We defined QRS fragmentation as the presence of low-voltage waves in the terminal portion of the QRS complex in at least 2 contiguous leads. We found a significant negative correlation between QRS width and right ventricular function, as well as a positive correlation with right ventricular volume. The receiver operating characteristic curve indicated a cut-off point for QRS width of 140ms, which showed good sensitivity for a diagnosis of right ventricular dilation (> 80%) and dysfunction (> 95%). In logistic regression models, a QRS duration > 140ms was found to be the only independent predictor of right ventricular dilation and dysfunction. Electrocardiography is a rapid, widely available, and reproducible tool. QRS width constitutes an independent predictor of the presence of right ventricular dilation and dysfunction. This study is the first to provide a cutoff value for QRS width to screen for right ventricle involvement. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Treatment of denture-related stomatitis improves endothelial function assessed by flow-mediated vascular dilation.

PubMed

Osmenda, Grzegorz; Maciąg, Joanna; Wilk, Grzegorz; Maciąg, Anna; Nowakowski, Daniel; Loster, Jolanta; Dembowska, Elżbieta; Robertson, Douglas; Guzik, Tomasz; Cześnikiewicz-Guzik, Marta

2017-02-01

The presence of oral inflammation has recently been linked with the pathogenesis of cardiovascular diseases. While numerous studies have described links between periodontitis and endothelial dysfunction, little is known about the influence of denture-related stomatitis (DRS) on cardiovascular risk. Therefore, the aim of this study was to determine whether the treatment of DRS can lead to improvement of the clinical measures of vascular dysfunction. The DRS patients were treated with a local oral antifungal agent for 3 weeks. Blood pressure, flow-mediated dilatation (FMD) and nitroglycerine-mediated vascular dilatation (NMD) were measured during three study visits: before treatment, one day and two months after conclusion of antifungal therapy. Flow-mediated dilatation measurements showed significant improvement of endothelial function 2 months after treatment (FMD median 5%, 95 CI: 3-8.3 vs. 11%, 95% CI: 8.8-14.4; p < 0.01), while there was no difference in control, endothelium-independent vasorelaxations (NMD; median = 15.3%, 95% CI: 10.8-19.3 vs. 12.7%, 95% CI: 10.6-15; p = 0.3). Other cardiovascular parameters such as systolic (median = 125 mm Hg; 95% CI: 116-129 vs. 120 mm Hg, 95% CI: 116-126; p = 0.1) as well as diastolic blood pressure and heart rate (median = 65.5 bpm, 95% CI: 56.7-77.7 vs. 71 bpm, 95% CI: 66.7-75; p = 0.5) did not change during or after the treatment. Treatment of DRS is associated with improvement of endothelial function. Since endothelial dysfunction is known to precede the development of severe cardiovascular disorders such as atherosclerosis and hypertension, patients should be more carefully screened for DRS in general dental practice, and immediate DRS treatment should be advised.

Influence of Depth of Hypnosis on Pupillary Reactivity to a Standardized Tetanic Stimulus in Patients Under Propofol-Remifentanil Target-Controlled Infusion: A Crossover Randomized Pilot Study.

PubMed

Sabourdin, Nada; Peretout, Jean-Baptiste; Khalil, Eliane; Guye, Marie-Laurence; Louvet, Nicolas; Constant, Isabelle

2018-01-01

Pupillometry allows the measurement of pupillary diameter variations in response to nociceptive stimuli. This technique has been used to monitor the balance between analgesia and nociception. Under general anesthesia, the amplitude of pupillary dilation is related to the amount of administered opioids. The objective of this study was to determine whether at a constant infusion rate of opioids, the pupillary response was influenced by depth of hypnosis assessed by the bispectral index (BIS). Twelve patients (14-20 years) anesthetized for orthopedic surgery were included. Under propofol-remifentanil target-controlled infusion, remifentanil effect site target concentration was fixed at 1 ng/mL. Two measures of pupillary reflex dilation were performed on each patient in a randomized order: one at BIS 55 and one at BIS 25. These levels of BIS were obtained by adjusting propofol target concentration and maintained for 10 minutes before each measure. For each measure, we applied a standardized tetanic stimulation on the patient's forearm (60 mA, 100 Hz, 5 seconds). All measures were performed before the beginning of surgery. Pupillary dilation was significantly greater at BIS 55 than at BIS 25: 32.1% ± 5.3% vs 10.4% ± 2.5% (mean difference estimate [95% confidence interval]: 21.8% [12.9-30.6], P < .001), without carryover effect (P = .30) nor period effect (P = .52). Hemodynamic parameters and BIS were not modified by the stimulation. In patients receiving a constant infusion of remifentanil at a target concentration of 1 ng/mL, pupillary dilation after a standardized tetanic stimulation was influenced by depth of hypnosis assessed by the BIS.

Endothelial dysfunction in normoglycaemic first-degree relatives of type 2 diabetes mellitus complicated with hyperuricaemia.

PubMed

Zhang, Junxia; Xiang, Lin; Zhang, Bilin; Cheng, Yangyang

2017-03-01

To reveal the effect of hyperuricaemia on endothelial function in normoglycaemic first-degree relatives of type 2 diabetes mellitus. In all, 40 first-degree relatives of type 2 diabetes mellitus with hyperuricaemia, 40 first-degree relatives of type 2 diabetes mellitus with normouricaemia and 35 healthy subjects without diabetic family history were recruited in this study. Anthropometric parameters as well as blood pressure, blood lipids, fasting blood glucose, fasting insulin, C-reactive protein, tumour necrosis factor-α and interleukin-6 were measured. Insulin resistance was assessed with homoeostasis model assessment index-insulin resistance index. To assess endothelial function, high-resolution ultrasonography was used for measuring flow- and nitroglycerine-mediated brachial artery vasodilation. When compared with control, flow-mediated dilation was lower in first-degree relatives with or without hyperuricaemia (both p < 0.001). When compared with first-degree relative subjects with normouricaemia, there were lower flow-mediated dilation ( p < 0.001) and higher levels of uric acid ( p < 0.001), fasting blood glucose ( p < 0.001), C-reactive protein ( p = 0.001), tumour necrosis factor-α ( p < 0.001) and interleukin-6 ( p < 0.001) in first-degree relative subjects with hyperuricaemia. Flow-mediated dilation was found to be negatively related to uric acid ( r = -0.597, p < 0.001). Stepwise multiple regressions demonstrated that uric acid was a significant determinant of flow-mediated dilation independent of other variables in first-degree relatives of type 2 diabetes mellitus (β = -0.677, p < 0.001; confidence interval: -0.010 to -0.006). Further endothelial dysfunction is found in normoglycaemic first-degree relatives of type 2 diabetes mellitus complicated with hyperuricaemia.

Prediction of High-Grade Vesicoureteral Reflux after Pediatric Urinary Tract Infection: External Validation Study of Procalcitonin-Based Decision Rule

PubMed Central

Leroy, Sandrine; Bouissou, François; Fernandez-Lopez, Anna; Gurgoze, Metin K.; Karavanaki, Kyriaki; Ulinski, Tim; Bressan, Silvia; Vaos, Geogios; Leblond, Pierre; Coulais, Yvon; Cubells, Carlos Luaces; Aygun, A. Denizmen; Stefanidis, Constantinos J.; Bensman, Albert; DaDalt, Liviana; Gardikis, Stefanos; Bigot, Sandra; Gendrel, Dominique; Bréart, Gérard; Chalumeau, Martin

2011-01-01

Background Predicting vesico-ureteral reflux (VUR) ≥3 at the time of the first urinary tract infection (UTI) would make it possible to restrict cystography to high-risk children. We previously derived the following clinical decision rule for that purpose: cystography should be performed in cases with ureteral dilation and a serum procalcitonin level ≥0.17 ng/mL, or without ureteral dilatation when the serum procalcitonin level ≥0.63 ng/mL. The rule yielded a 86% sensitivity with a 46% specificity. We aimed to test its reproducibility. Study Design A secondary analysis of prospective series of children with a first UTI. The rule was applied, and predictive ability was calculated. Results The study included 413 patients (157 boys, VUR ≥3 in 11%) from eight centers in five countries. The rule offered a 46% specificity (95% CI, 41–52), not different from the one in the derivation study. However, the sensitivity significantly decreased to 64% (95%CI, 50–76), leading to a difference of 20% (95%CI, 17–36). In all, 16 (34%) patients among the 47 with VUR ≥3 were misdiagnosed by the rule. This lack of reproducibility might result primarily from a difference between derivation and validation populations regarding inflammatory parameters (CRP, PCT); the validation set samples may have been collected earlier than for the derivation one. Conclusions The rule built to predict VUR ≥3 had a stable specificity (ie. 46%), but a decreased sensitivity (ie. 64%) because of the time variability of PCT measurement. Some refinement may be warranted. PMID:22216314

Efficacy of pneumodilation in achalasia after failed Heller myotomy.

PubMed

Saleh, C M G; Ponds, F A M; Schijven, M P; Smout, A J P M; Bredenoord, A J

2016-11-01

Heller myotomy is an effective treatment for the majority of achalasia patients. However, a small proportion of patients suffer from persistent or recurrent symptoms after surgery and they are usually subsequently treated with pneumodilation (PD). Data on the efficacy of PD as secondary treatment for achalasia are scarce. Therefore, this study aimed to investigate the efficacy of PD as treatment for achalasia patients suffering from persistent or recurrent symptoms after Heller myotomy. Patients with recurrent or persistent symptoms (Eckardt score >3) after Heller myotomy were selected. Patients were treated with PD, using a graded distension protocol with balloon sizes ranging from 30 to 40 mm. After each dilation symptoms were assessed to evaluate whether a subsequent dilation with a larger balloon size was required. Patients with recurrent or persistent symptoms (Eckardt score >3) after treatment with a 40-mm balloon were identified as failures. Twenty-four patients were included in total; 15 patients with achalasia type I, seven with achalasia type II and two with achalasia type III. Median relapse time was 2.5 years after Heller myotomy (IQR: 9 years and 3 months). Three patients were not suitable for PD; one patient was morbidly obese and not fit for any form of sedation and two had a siphon-shaped esophagus leaving 21 patients to treat. Eight patients were successfully treated with a single 30-mm balloon dilation (median follow-up time: 6.5 years; IQR: 7.5 years). Four patients required dilations with 30- and 35-mm balloons (median follow-up time: 11 years; IQR: 3 years). Nine patients failed on the 35-mm balloon dilation and underwent a subsequent dilation with a 40-mm balloon, and all failed on this balloon as well. Thus, PD was successful in 12 of the 21 treatable patients, resulting in a success rate of 57% for treatable patients or 50% for all patients. Baseline Eckardt scores were also higher in those that failed (median: 8; IQR: 2) than those that were treated successfully (median: 5.5; IQR: 2) treated (p = 0.009). Furthermore, baseline barium column height at 5 min was higher in patients with failed (median: 6 cm; IQR: 6 cm) treatment than in patients with successful (median: 2.6 cm; IQR: 4.7 cm) treatment (p = 0.016). Baseline lower esophageal sphincter pressure was not different between patients who were treated successfully (median: 11 mmHg; IQR: 5 mmHg) and those that failed on PD (median: 17.5 mmHg; IQR: 10.8 mmHg) treatment (p > 0.05). Baseline symptom pattern was also not a predictor of successful treatment. No adverse events were recorded during or after PD. Pneumodilation for recurrent symptoms after previous Heller myotomy is safe and has a modest success rate of 57%, using 30- and 35-mm balloons. Patients with recurrent symptoms after PD with 35-mm balloon are likely to also fail after subsequent dilation with a 40-mm balloon. © 2016 John Wiley & Sons Ltd.

Compressibility effects on turbulent mixing

NASA Astrophysics Data System (ADS)

Panickacheril John, John; Donzis, Diego

2016-11-01

We investigate the effect of compressibility on passive scalar mixing in isotropic turbulence with a focus on the fundamental mechanisms that are responsible for such effects using a large Direct Numerical Simulation (DNS) database. The database includes simulations with Taylor Reynolds number (Rλ) up to 100, turbulent Mach number (Mt) between 0.1 and 0.6 and Schmidt number (Sc) from 0.5 to 1.0. We present several measures of mixing efficiency on different canonical flows to robustly identify compressibility effects. We found that, like shear layers, mixing is reduced as Mach number increases. However, data also reveal a non-monotonic trend with Mt. To assess directly the effect of dilatational motions we also present results with both dilatational and soleniodal forcing. Analysis suggests that a small fraction of dilatational forcing decreases mixing time at higher Mt. Scalar spectra collapse when normalized by Batchelor variables which suggests that a compressive mechanism similar to Batchelor mixing in incompressible flows might be responsible for better mixing at high Mt and with dilatational forcing compared to pure solenoidal mixing. We also present results on scalar budgets, in particular on production and dissipation. Support from NSF is gratefully acknowledged.

Grounding by Attention Simulation in Peripersonal Space: Pupils Dilate to Pinch Grip But Not Big Size Nominal Classifier.

PubMed

Lobben, Marit; Bochynska, Agata

2018-03-01

Grammatical categories represent implicit knowledge, and it is not known if such abstract linguistic knowledge can be continuously grounded in real-life experiences, nor is it known what types of mental states can be simulated. A former study showed that attention bias in peripersonal space (PPS) affects reaction times in grammatical congruency judgments of nominal classifiers, suggesting that simulated semantics may include reenactment of attention. In this study, we contrasted a Chinese nominal classifier used with nouns denoting pinch grip objects with a classifier for nouns with big object referents in a pupil dilation experiment. Twenty Chinese native speakers read grammatical and ungrammatical classifier-noun combinations and made grammaticality judgment while their pupillary responses were measured. It was found that their pupils dilated significantly more to the pinch grip classifier than to the big object classifier, indicating attention simulation in PPS. Pupil dilations were also significantly larger with congruent trials on the whole than in incongruent trials, but crucially, congruency and classifier semantics were independent of each other. No such effects were found in controls. Copyright © 2017 Cognitive Science Society, Inc.

Digital Photoplethysmography for Assessment of Arterial Stiffness: Repeatability and Comparison with Applanation Tonometry

PubMed Central

Östling, Gerd; Nilsson, Peter M.

2015-01-01

Introduction Arterial stiffness is an independent risk factor for cardiovascular morbidity and can be assessed by applanation tonometry by measuring pulse wave velocity (PWV) and augmentation index (AIX) by pressure pulse wave analysis (PWA). As an inexpensive and operator independent alternative, photoelectric plethysmography (PPG) has been introduced with analysis of the digital volume pulse wave (DPA) and its second derivatives of wave reflections. Objective The objective was to investigate the repeatability of arterial stiffness parameters measured by digital pulse wave analysis (DPA) and the associations to applanation tonometry parameters. Methods and Results 112 pregnant and non-pregnant individuals of different ages and genders were examined with SphygmoCor arterial wall tonometry and Meridian DPA finger photoplethysmography. Coefficients of repeatability, Bland-Altman plots, intraclass correlation coefficients and correlations to heart rate (HR) and body height were calculated for DPA variables, and the DPA variables were compared to tonometry variables left ventricular ejection time (LVET), PWV and AIX. No DPA variable showed any systematic measurement error or excellent repeatability, but dicrotic index (DI), dicrotic dilatation index (DDI), cardiac ejection elasticity index (EEI), aging index (AI) and second derivatives of the crude pulse wave curve, b/a and e/a, showed good repeatability. Overall, the correlations to AIX were better than to PWV, with correlations coefficients >0.70 for EEI, AI and b/a. Considering the level of repeatability and the correlations to tonometry, the overall best DPA parameters were EEI, AI and b/a. The two pansystolic time parameters, ejection time compensated (ETc) by DPA and LVET by tonometry, showed a significant but weak correlation. Conclusion For estimation of the LV function, ETc, EEI and b/a are suitable, for large artery stiffness EEI, and for small arteries DI and DDI. The only global parameter, AI, showed a high repeatability and the overall best correlations with AIX and PWV. PMID:26291079

Genetics Home Reference: X-linked dilated cardiomyopathy

MedlinePlus

... Twitter Home Health Conditions X-linked dilated cardiomyopathy X-linked dilated cardiomyopathy Printable PDF Open All Close ... Javascript to view the expand/collapse boxes. Description X-linked dilated cardiomyopathy is a form of heart ...

Segmental dilatation of the ileum covered almost entirely by gastric mucosa: report of a case.

PubMed

Kobayashi, Tsutomu; Uchida, Nobuyuki; Shiojima, Masayuki; Sasamoto, Hajime; Shimura, Tatsuo; Takahasi, Atsusi; Kuwano, Hiroyuki

2007-01-01

A 13-year-old boy was referred to our hospital for investigation of intermittent abdominal colic pain and vomiting. He underwent an emergency laparotomy, which revealed a volvulus and segmental dilatation of the ileum. The dilated intestine was not associated with poor intestinal circulation. Because the dilated ileum did not seem to be the cause of the volvulus, we simply released the volvulus. However, after surgery, the patient still suffered from persistent abdominal pain, further episodes of volvulus, and invagination of the dilated ileum. Thus, we performed a second operation to resect the segmental dilatation of the ileum. Pathological examination revealed that most of the mucosa of the dilated ileum was composed of ectopic gastric mucosa. We postulate that the ectopic gastric mucosa led to the formation of segmental dilatation of the ileum.

Corrected Integral Shape Averaging Applied to Obstructive Sleep Apnea Detection from the Electrocardiogram

NASA Astrophysics Data System (ADS)

Boudaoud, S.; Rix, H.; Meste, O.; Heneghan, C.; O'Brien, C.

2007-12-01

We present a technique called corrected integral shape averaging (CISA) for quantifying shape and shape differences in a set of signals. CISA can be used to account for signal differences which are purely due to affine time warping (jitter and dilation/compression), and hence provide access to intrinsic shape fluctuations. CISA can also be used to define a distance between shapes which has useful mathematical properties; a mean shape signal for a set of signals can be defined, which minimizes the sum of squared shape distances of the set from the mean. The CISA procedure also allows joint estimation of the affine time parameters. Numerical simulations are presented to support the algorithm for obtaining the CISA mean and parameters. Since CISA provides a well-defined shape distance, it can be used in shape clustering applications based on distance measures such as[InlineEquation not available: see fulltext.]-means. We present an application in which CISA shape clustering is applied to P-waves extracted from the electrocardiogram of subjects suffering from sleep apnea. The resulting shape clustering distinguishes ECG segments recorded during apnea from those recorded during normal breathing with a sensitivity of[InlineEquation not available: see fulltext.] and specificity of[InlineEquation not available: see fulltext.].

Arithmetic and algebraic problem solving and resource allocation: the distinct impact of fluid and numerical intelligence.

PubMed

Dix, Annika; van der Meer, Elke

2015-04-01

This study investigates cognitive resource allocation dependent on fluid and numerical intelligence in arithmetic/algebraic tasks varying in difficulty. Sixty-six 11th grade students participated in a mathematical verification paradigm, while pupil dilation as a measure of resource allocation was collected. Students with high fluid intelligence solved the tasks faster and more accurately than those with average fluid intelligence, as did students with high compared to average numerical intelligence. However, fluid intelligence sped up response times only in students with average but not high numerical intelligence. Further, high fluid but not numerical intelligence led to greater task-related pupil dilation. We assume that fluid intelligence serves as a domain-general resource that helps to tackle problems for which domain-specific knowledge (numerical intelligence) is missing. The allocation of this resource can be measured by pupil dilation. Copyright © 2014 Society for Psychophysiological Research.

Evolution of fault zones in carbonates with mechanical stratigraphy - Insights from scale models using layered cohesive powder

NASA Astrophysics Data System (ADS)

van Gent, Heijn W.; Holland, Marc; Urai, Janos L.; Loosveld, Ramon

2010-09-01

We present analogue models of the formation of dilatant normal faults and fractures in carbonate fault zones, using cohesive hemihydrate powder (CaSO 4·½H 2O). The evolution of these dilatant fault zones involves a range of processes such as fragmentation, gravity-driven breccia transport and the formation of dilatant jogs. To allow scaling to natural prototypes, extensive material characterisation was done. This showed that tensile strength and cohesion depend on the state of compaction, whereas the friction angle remains approximately constant. In our models, tensile strength of the hemihydrate increases with depth from 9 to 50 Pa, while cohesion increases from 40 to 250 Pa. We studied homogeneous and layered material sequences, using sand as a relatively weak layer and hemihydrate/graphite mixtures as a slightly stronger layer. Deformation was analyzed by time-lapse photography and Particle Image Velocimetry (PIV) to calculate the evolution of the displacement field. With PIV the initial, predominantly elastic deformation and progressive localization of deformation are observed in detail. We observed near-vertical opening-mode fractures near the surface. With increasing depth, dilational shear faults were dominant, with releasing jogs forming at fault-dip variations. A transition to non-dilatant shear faults was observed near the bottom of the model. In models with mechanical stratigraphy, fault zones are more complex. The inferred stress states and strengths in different parts of the model agree with the observed transitions in the mode of deformation.

Task-evoked pupillometry provides a window into the development of short-term memory capacity.

PubMed

Johnson, Elizabeth L; Miller Singley, Alison T; Peckham, Andrew D; Johnson, Sheri L; Bunge, Silvia A

2014-01-01

The capacity to keep multiple items in short-term memory (STM) improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.6 years) and adults (n = 54, mean age = 27.5 years) performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC) and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM overload task, after which the adults' pupils continued to dilate and the children's began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM.

Congenital esophageal stenosis associated with esophageal atresia.

PubMed

McCann, F; Michaud, L; Aspirot, A; Levesque, D; Gottrand, F; Faure, C

2015-04-01

Congenital esophageal stenosis (CES) is a rare clinical condition but is frequently associated with esophageal atresia (EA). The aim of this study is to report the diagnosis, management, and outcome of CES associated with EA. Medical charts of CES-EA patients from Lille University Hospital, Sainte-Justine Hospital, and Montreal Children's Hospital were retrospectively reviewed. Seventeen patients (13 boys) were included. The incidence of CES in patients with EA was 3.6%. Fifteen patients had a type C EA, one had a type A EA, and one had an isolated tracheoesophageal fistula. Seven patients had associated additional malformations. The mean age at diagnosis was 11.6 months. All but two patients had non-specific symptoms such as regurgitations or dysphagia. One CES was diagnosed at the time of surgical repair of EA. In 12 patients, CES was suspected based on abnormal barium swallow. In the remaining four, the diagnostic was confirmed by esophagoscopy. Eleven patients were treated by dilation only (1-3 dilations/patient). Six patients underwent surgery (resection and anastomosis) because of failure of attempted dilations (1-7 dilations/patient). Esophageal perforation was encountered in three patients (18%). Three patients had histologically proven tracheobronchial remnants. CES associated with EA is frequent. A high index of suspicion for CES must remain in the presence of EA. Dilatation may be effective to treat some of them, but perforation is frequent. Surgery may be required, especially in CES secondary to ectopic tracheobronchial remnants. © 2014 International Society for Diseases of the Esophagus.

Esophageal dilatation using the Eder Puestow dilators.

PubMed

Royston, C M; Dowling, B L; Gear, M W

1976-06-01

We have performed fifty-one dilatations in twenty-six patients using an end-viewing fiberoptic endoscope and Eder Puestow dilators. All (except two) were performed using intravenous diazepam, the majority on an outpatient basis. The only complication has been a single case of aspiration pneumonia. We have found this method of esophageal dilatation particularly useful in the preoperative dilatation of benign strictures, and in those elderly frail patients who are unsuitable for surgery. Transthoracic resection of the stricture is avoided and thus transabdominal repair of the hiatus hernia may be undertaken.

Effect of demulsifiers on interfacial properties governing crude oil demulsification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukherjee, S.; Kushnick, A.P.

1987-01-01

The purpose of this paper is to illustrate how various parameters such as interfacial tension, interfacial shear viscosity, dynamic interfacial tension gradient, dilational elasticity and demulsifier clustering affect the demulsification effectiveness. The authors believe such an understanding is needed for developing more effective demulsifiers. At small thicknesses, an interfacial oil film can rupture if a continuous hydrophilic pathway exists between the droplets. Such a pathway can be provided by a demulsifier by forming water swollen reverse micelle-like clusters. They believe the differences in the effectiveness between P1 and P2 at low concentrations may be related to this phenomenon. The authorsmore » found that with both P1 and P2, the crude oil-brine interfacial shear viscosity is less than 0.1 surface poise. The interfacial dilational measurements also do not reveal any significant differences in their dynamic tension properties. But the interfacial tension vs. concentration curves show significant differences. The leveling of interfacial tension implies formation of clusters. The data indicate that the demulsifier P1 will form such clusters in the crude oil at a lower concentration than P2. Thus, other parameters being equal, the demulsifier P1 will be more efficient at a lower concentration than P2 for this crude oil emulsion.« less

New surgical concepts: nasal tip function.

PubMed

Galli, J J; Zavalla, C A; Vivas, D G; Prado, C; Zanetta, G C

1997-01-01

Since the birth of plastic surgery, rhinoplasty has been an outstanding chapter. Facial balance has been endeavoured with two parameters: size and shape. Now, however, the criterion for harmony has involved two more parameters; position and function. Position is related to other facial elements, such as, upper maxilla, upper lip, forehead, and frontonasal sulcus. Function is important because nasal superficial musculoaponeurotic system (SMAS) muscles are important for Nasal tip movement. To understand this better, we must analyze the nasal SMAS, which consists of primary or intrinsic and secondary or extrinsic muscles. When the extrinsics contract, they allow function of the intrinsics. They are the ala nasalis dilator, the ala nasalis elevator, the tranversus, and the tip depressor. Obvious hypertrophies of the dilator and the elevator has been observed in young athletes. Our method combines conventional, new, and modern aspects. It is conventional because the alar cartilages have been completely freed by intercartilaginous and marginal approaches, and the upper or lower border trimmed according to the case. It is more important to measure how much cartilage is left, than how much is removed. The new aspect is consideration of nasal SMAS to treat short noses that display a tendency to descend with laughter, and the modern aspect is the evaluation of dynamic surgical results, apart from the static.

Importance of anatomical dominance in the evaluation of coronary dilatation in Kawasaki disease.

PubMed

Dionne, Audrey; Hanna, Baher; Trinh Tan, Frédérick; Desjardins, Laurent; Lapierre, Chantale; Déry, Julie; Fournier, Anne; Dahdah, Nagib

2017-07-01

Introduction In Kawasaki disease, although coronary dilatation is attributed to vasculitis, the effect of myocardial inflammation is underestimated. Coronary dilatations are determined by Z-scores, which do not take into account dominance. The aim of the present study was to describe the impact of coronary dominance on dilatation in Kawasaki disease. We performed a retrospective analysis of coronary dilatations according to angiography categorisation of dominance. Of 28 patients (2.6 [0.2-10.1] years), right dominance was present in 15 patients and left in 13. Early dilatation was present in all patients, of whom 11 were ipsilateral to the dominant segment and 17 contralateral. Ipsilateral dilatations were present at diagnosis (9/11 versus 6/17, p=0.02) compared with contralateral dilatations, which developed 2 weeks after diagnosis (9/11 versus 16/17, p=0.29). Coronary artery Z-scores of patients with contralateral dilatation increased at 2 weeks, before returning to baseline values (2.0±2.2 at diagnosis, 4.1±1.8 at 2 weeks, 1.8±1.2 at 3-6 months, p=0.001), compared with patients with ipsilateral dilatation in whom Z-scores were maximal at diagnosis and remained stable (3.0±0.9, 2.7±1.1 and 2.6±1.5, respectively, p=0.13). Dominant coronary artery Z-scores were higher compared with non-dominant segments at diagnosis (3.0±0.9 versus 1.0±0.8, p<0.001) and at late follow-up (2.6±1.5 versus 0.4±1.4, p=0.002) in patients with ipsilateral dilatation. Progression of coronary dilatation after diagnosis may be a sign of dilatation secondary to vasculitis, as opposed to regression of Z-scores in ipsilateral dilatations, probably related to physiological vasodilatation in response to carditis. This needs to be validated in larger studies against vasculitic and myocardial inflammatory markers.

Modeling the pressure-dilatation correlation

NASA Technical Reports Server (NTRS)

Sarkar, S.

1991-01-01

It is generally accepted that pressure dilatation, which is an additional compressibility term in turbulence transport equations, may be important for high speed flows. Recent direct simulations of homogeneous shear turbulence have given concrete evidence that the pressure dilatation is important insofar that it contributes to the reduced growth of turbulent kinetic energy due to compressibility effects. The problem of modeling pressure dilatation is addressed. A component of the pressure dilatation is isolated which exhibits temporal oscillations and, using direct numerical simulations of homogeneous shear turbulence and isotropic turbulence, show that it has a negligible contribution to the evolution of turbulent kinetic energy. Then, an analysis for the case of homogeneous turbulence is performed to obtain a model for the nonoscillatory pressure dilatation. This model algebraically relates the pressure dilatation to quantities traditionally obtained in incompressible turbulence closures. The model is validated by direct comparison with the pressure dilatation data obtained from the simulations.

Numerical Simulation of Slow Slip and Dynamic Rupture in the Cascadia Subduction Zone

NASA Astrophysics Data System (ADS)

Segall, P.; Bradley, A. M.

2010-12-01

Seismic and geodetic observations are consistent with slow-slip events (SSE) occurring down-dip of the locked megathrust in regions of anomalously high pore pressure p. We hypothesize that at low effective normal stress (σ -p), dilatancy stabilizes velocity weakening faults, whereas at higher (σ -p), thermal pressurization overwhelms dilatancy, which leads to dynamic slip. We present two-dimensional half-space simulations that include rate-state friction, dilatancy (following Segall and Rice [1995]), and heat and pore-fluid flow normal to the fault. The system of equations is an index-1 differential algebraic equation (DAE) in slip δ , state θ , fault zone porosity φ , p, and T. We integrate θ , φ , and δ explicitly; solve the stress-balance equation on the fault; and integrate p and T implicitly. Numerical methods are discussed in Bradley and Segall [this meeting]. We take depth-variable frictional properties (based on lab experiments on gabbro, similar to Liu and Rice [2009]) that yield a transition from velocity strengthening to weakening friction at ˜ 33 km depth. We assume low effective stress, presumed to be driven by dehydration reactions, in the ˜ 25 to ˜ 40 km depth range. Simulations reveal generic behavior: dynamic events (DE) repeat every few hundred years, and between each DE is a quiescent period and then a long sequence of SSE. If the width of the low effective stress region exceeds a critical dimension, the SSE penetrate up-dip with time. During this period, the SSE moment rates generally (but not monotonically) increase with time. Eventually slip speeds become high enough to induce thermal pressurization, which nucleates a DE. The predicted behavior, in terms of SSE slip, stress drop, and repeat time bear many similarities to SSE in Cascadia. In related experiments [Chen et al, this meeting] we explore the role of heterogeneous permeability in generating low-frequency earthquakes and tremor. In all cases examined, slow slip fails to accommodate plate motion, and DE propagate through the SSE zone. To test model predictions against GPS data, we develop a pseudo-3D method that accounts for the markedly non-2D geometry of the plate interface. The approach employs 3D elastic Green's functions but assumes that slip rate is a function of depth only, as computed in the physics based model. We discuss whether or not steady creep is required above the SSE region to satisfy the inter-ETS GPS velocities, and the distribution of physical parameters that might permit this to occur (without artificially requiring an additional velocity strengthening region).

Heart rate variability in idiopathic dilated cardiomyopathy: relation to disease severity and prognosis.

PubMed Central

Yi, G.; Goldman, J. H.; Keeling, P. J.; Reardon, M.; McKenna, W. J.; Malik, M.

1997-01-01

OBJECTIVE: To assess the clinical importance of heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (DCM). PATIENTS AND METHODS: Time domain analysis of 24 hour HRV was performed in 64 patients with DCM, 19 of their relatives with left ventricular enlargement (possible early DCM), and 33 healthy control subjects. RESULTS: Measures of HRV were reduced in patients with DCM compared with controls (P < 0.05). HRV parameters were similar in relatives and controls. Measures of HRV were lower in DCM patients in whom progressive heart failure developed (n = 28) than in those who remained clinically stable (n = 36) during a follow up of 24 (20) months (P = 0.0001). Reduced HRV was associated with NYHA functional class, left ventricular end diastolic dimension, reduced left ventricular ejection fraction, and peak exercise oxygen consumption (P < 0.05) in all patients. DCM patients with standard deviation of normal to normal RR intervals calculated over the 24 hour period (SDNN) < 50 ms had a significantly lower survival rate free of progressive heart failure than those with SDNN > 50 ms (P = 0.0002, at 12 months; P = 0.0001, during overall follow up). Stepwise multiple regression analysis showed that SDNN < 50 ms identified, independently of other clinical variables, patients who were at increased risk of developing progressive heart failure (P = 0.0004). CONCLUSIONS: HRV is reduced in patients with DCM and related to disease severity. HRV is clinically useful as an early non-invasive marker of DCM deterioration. PMID:9068391

Predictors of electrical storm in patients with idiopathic dilated cardiomyopathy--how to stratify the risk of electrical storm.

PubMed

Takigawa, Masateru; Noda, Takashi; Kurita, Takashi; Aihara, Naohiko; Yamada, Yuko; Okamura, Hideo; Satomi, Kazuhiro; Suyama, Kazuhiro; Shimizu, Wataru; Kamakura, Shiro

2010-09-01

Electrical storm (ES) is a serious problem in patients with an implantable cardioverter defibrillator (ICD). However, insufficient reports have indicated the predictors of ES in ICD patients with idiopathic dilated cardiomyopathy (DCM). The purpose of this study was to clarify the predictors of ES for risk stratification in DCM patients with an ICD. Of 446 ICD patients, 53 DCM patients were included in this study. During a mean follow-up of 55+/-36 months, ES (> or =3 times appropriate ICD therapy within 24 h) occurred in 18/53 (34%) patients. According to multivariate Cox proportional hazard regression analysis, a duration of the terminal low amplitude signals of <40 microV (LAS40) (HR 1.4/10 ms increase, 95% confidence interval (CI) 1.1-2.1; P=0.0049) or root mean square voltage of the last 40 ms of the QRS complex (RMS40) (HR 0.88/1 microV, 95%CI 0.77-0.96; P=0.001) on the signal averaged electrocardiogram, and a history of atrial fibrillation (AF) before ICD implantation (HR 2.3, 95%CI 1.2-5.0; P=0.013) were independently associated with an increased risk of ES. Our data indicated that a longer LAS40, lower RMS40 and history of AF before ICD implantation could strongly predict ES, and the combination of those parameters could effectively stratify the risk of ES in DCM patients.

Vaginal dilator therapy for women receiving pelvic radiotherapy.

PubMed

Miles, Tracie; Johnson, Nick

2014-09-08

Vaginal dilation therapy is advocated after pelvic radiotherapy to prevent stenosis (abnormal narrowing of the vagina), but can be uncomfortable and psychologically distressing. To assess the benefits and harms of different types of vaginal dilation methods offered to women treated by pelvic radiotherapy for cancer. Searches included the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 5), MEDLINE (1950 to June week 2, 2013), EMBASE (1980 to 2013 week 24) and CINAHL (1982 to 2013). Comparative data of any type, which evaluated dilation or penetration of the vagina after pelvic radiotherapy treatment for cancer. Two review authors independently assessed whether potentially relevant studies met the inclusion criteria. We found no trials and therefore analysed no data. We identified no studies for inclusion in the original review or for this update. However, we felt that some studies that were excluded warranted discussion. These included one randomised trial (RCT), which showed no improvement in sexual scores associated with encouraging women to practise dilation therapy; a recent small RCT that did not show any advantage to dilation over vibration therapy during radiotherapy; two non-randomised comparative studies; and five correlation studies. One of these showed that objective measurements of vaginal elasticity and length were not linked to dilation during radiotherapy, but the study lacked power. One study showed that women who dilated tolerated a larger dilator, but the risk of objectivity and bias with historical controls was high. Another study showed that the vaginal measurements increased in length by a mean of 3 cm after dilation was introduced 6 to 10 weeks after radiotherapy, but there was no control group; another case series showed the opposite. Three recent studies showed less stenosis associated with prophylactic dilation after radiotherapy. One small case series suggested that dilation years after radiotherapy might restore the vagina to a functional length. There is no reliable evidence to show that routine, regular vaginal dilation during radiotherapy treatment prevents stenosis or improves quality of life. Several observational studies have examined the effect of dilation therapy after radiotherapy. They suggest that frequent dilation practice is associated with lower rates of self reported stenosis. This could be because dilation is effective or because women with a healthy vagina are more likely to comply with dilation therapy instructions compared to women with strictures. We would normally suggest that a RCT is needed to distinguish between a casual and causative link, but pilot studies highlight many reasons why RCT methodology is challenging in this area.

Selection of Reference Genes for Quantitative Real Time PCR (qPCR) Assays in Tissue from Human Ascending Aorta

PubMed Central

Rueda-Martínez, Carmen; Lamas, Oscar; Mataró, María José; Robledo-Carmona, Juan; Sánchez-Espín, Gemma; Jiménez-Navarro, Manuel; Such-Martínez, Miguel; Fernández, Borja

2014-01-01

Dilatation of the ascending aorta (AAD) is a prevalent aortopathy that occurs frequently associated with bicuspid aortic valve (BAV), the most common human congenital cardiac malformation. The molecular mechanisms leading to AAD associated with BAV are still poorly understood. The search for differentially expressed genes in diseased tissue by quantitative real-time PCR (qPCR) is an invaluable tool to fill this gap. However, studies dedicated to identify reference genes necessary for normalization of mRNA expression in aortic tissue are scarce. In this report, we evaluate the qPCR expression of six candidate reference genes in tissue from the ascending aorta of 52 patients with a variety of clinical and demographic characteristics, normal and dilated aortas, and different morphologies of the aortic valve (normal aorta and normal valve n = 30; dilated aorta and normal valve n = 10; normal aorta and BAV n = 4; dilated aorta and BAV n = 8). The expression stability of the candidate reference genes was determined with three statistical algorithms, GeNorm, NormFinder and Bestkeeper. The expression analyses showed that the most stable genes for the three algorithms employed were CDKN1β, POLR2A and CASC3, independently of the structure of the aorta and the valve morphology. In conclusion, we propose the use of these three genes as reference genes for mRNA expression analysis in human ascending aorta. However, we suggest searching for specific reference genes when conducting qPCR experiments with new cohort of samples. PMID:24841551

Determination of Prognostic Factors for Vaginal Mucosal Toxicity Associated With Intravaginal High-Dose Rate Brachytherapy in Patients With Endometrial Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahng, Agnes Y.; Dagan, Avner; Bruner, Deborah W.

2012-02-01

Purpose: The objective of this study was to determine the patient- and treatment-related prognostic factors associated with vaginal toxicity in patients who received intravaginal high dose rate (HDR) brachytherapy alone as adjuvant treatment for endometrial cancer. Secondary goals of this study included a quantitative assessment of optimal dilator use frequency and a crude assessment of clinical predictors for compliant dilator use. Methods and Materials: We retrospectively reviewed the charts of 100 patients with histologically confirmed endometrial cancer who underwent total hysterectomy and bilateral salpingo-oophorectomy with or without lymph node dissection and adjuvant intravaginal brachytherapy between 1995 and 2009 at themore » Hospital of University of Pennsylvania. The most common treatment regimen used was 21 Gy in three fractions (71 patients). Symptoms of vaginal mucosal toxicity were taken from the history and physical exams noted in the patients' charts and were graded according to the Common Toxicity Criteria for Adverse Events v. 4.02. Results: The incidence of Grade 1 or asymptomatic vaginal toxicity was 33% and Grade 2-3 or symptomatic vaginal toxicity was 14%. Multivariate analysis of age, active length, and dilator use two to three times a week revealed odds ratios of 0.93 (p = 0.013), 3.96 (p = 0.008), and 0.17 (p = 0.032) respectively. Conclusion: Increasing age, vaginal dilator use of at least two to three times a week, and shorter active length were found to be significantly associated with a decreased risk of vaginal stenosis. Future prospective studies are necessary to validate our findings.« less

Nonmydriatic ultrawide field retinal imaging compared with dilated standard 7-field 35-mm photography and retinal specialist examination for evaluation of diabetic retinopathy.

PubMed

Silva, Paolo S; Cavallerano, Jerry D; Sun, Jennifer K; Noble, Jason; Aiello, Lloyd M; Aiello, Lloyd Paul

2012-09-01

To compare nonmydriatic stereoscopic Optomap ultrawide field images with dilated stereoscopic Early Treatment Diabetic Retinopathy Study 7-standard field 35-mm color 30-degree fundus photographs (ETDRS photography) and clinical examination for determining diabetic retinopathy (DR) and diabetic macular edema (DME) severity. Single-site, prospective, comparative, instrument validation study. One hundred three diabetic patients (206 eyes) representing the full spectrum of DR severity underwent nonmydriatic ultrawide field 100-degree and 200-degree imaging, dilated ETDRS photography, and dilated fundus examination by a retina specialist. Two independent readers graded images to determine DR and DME severity. A third masked retina specialist adjudicated discrepancies. Based on ETDRS photography (n = 200), the results were as follows: no DR (n = 25 eyes [12.5%]), mild nonproliferative DR (NPDR; 47 [23.5%]), moderate NPDR (61 [30.5%]), severe NPDR (11 [5.5%]), very severe NPDR (3 [1.5%]), and proliferative DR (52 [2.5%]). One (0.5%) eye was ungradable and 6 eyes did not complete ETDRS photography. No DME was found in 114 eyes (57.0%), DME was found in 28 eyes (14.0%), and clinically significant DME was found in 47 eyes (23.5%), and 11 (5.5%) eyes were ungradable. Exact DR severity agreement between ultrawide field 100-degree imaging and ETDRS photography occurred in 84%, with agreement within 1 level in 91% (K(W) = 0.85; K = 0.79). Nonmydriatic ultrawide field images exactly matched clinical examination results for DR in 70% and were within 1 level in 93% (K(W) = 0.71; K = 0.61). Nonmydriatic ultrawide field imaging acquisition time was less than half that of dilated ETDRS photography (P < .0001). Nonmydriatic ultrawide field images compare favorably with dilated ETDRS photography and dilated fundus examination in determining DR and DME severity; however, they are acquired more rapidly. If confirmed in broader diabetic populations, nonmydriatic ultrawide field imaging may prove to be beneficial in DR evaluation in research and clinical settings. Copyright © 2012 Elsevier Inc. All rights reserved.

Percutaneous Dilational Tracheotomy in Solid-Organ Transplant Recipients.

PubMed

Ozdemirkan, Aycan; Ersoy, Zeynep; Zeyneloglu, Pinar; Gedik, Ender; Pirat, Arash; Haberal, Mehmet

2015-11-01

Solid-organ transplant recipients may require percutaneous dilational tracheotomy because of prolonged mechanical ventilation or airway issues, but data regarding its safety and effectiveness in solid-organ transplant recipients are scarce. Here, we evaluated the safety, effectiveness, and benefits in terms of lung mechanics, complications, and patient comfort of percutaneous dilational tracheotomy in solid-organ transplant recipients. Medical records from 31 solid-organ transplant recipients (median age of 41.0 years [interquartile range, 18.0-53.0 y]) who underwent percutaneous dilational tracheotomy at our hospital between January 2010 and March 2015 were analyzed, including primary diagnosis, comorbidities, duration of orotracheal intubation and mechanical ventilation, length of intensive care unit and hospital stays, the time interval between transplant to percutaneous dilational tracheotomy, Acute Physiology and Chronic Health Evaluation II score, tracheotomy-related complications, and pulmonary compliance and ratio of partial pressure of arterial oxygen to fraction of inspired oxygen. The median Acute Physiology and Chronic Health Evaluation II score on admission was 24.0 (interquartile range, 18.0-29.0). The median interval from transplant to percutaneous dilational tracheotomy was 105.5 days (interquartile range, 13.0-2165.0 d). The only major complication noted was left-sided pneumothorax in 1 patient. There were no significant differences in ratio of partial pressure of arterial oxygen to fraction of inspired oxygen before and after procedure (170.0 [interquartile range, 102.2-302.0] vs 210.0 [interquartile range, 178.5-345.5]; P = .052). However, pulmonary compliance results preprocedure and postprocedure were significantly different (0.020 L/cm H2O [interquartile range, 0.015-0.030 L/cm H2O] vs 0.030 L/cm H2O [interquartile range, 0.020-0.041 L/cm H2O); P = .001]). Need for sedation significantly decreased after tracheotomy (from 17 patients [54.8%] to 8 patients [25.8%]; P = .004]). Percutaneous dilational tracheotomy with bronchoscopic guidance is an efficacious and safe technique for maintaining airways in solidorgan transplant recipients who require prolonged mechanical ventilation, resulting in possible improvements in ventilatory mechanics and patient comfort.

Scaling of coupled dilatancy-diffusion processes in space and time

NASA Astrophysics Data System (ADS)

Main, I. G.; Bell, A. F.; Meredith, P. G.; Brantut, N.; Heap, M.

2012-04-01

Coupled dilatancy-diffusion processes resulting from microscopically brittle damage due to precursory cracking have been observed in the laboratory and suggested as a mechanism for earthquake precursors. One reason precursors have proven elusive may be the scaling in space: recent geodetic and seismic data placing strong limits on the spatial extent of the nucleation zone for recent earthquakes. Another may be the scaling in time: recent laboratory results on axi-symmetric samples show both a systematic decrease in circumferential extensional strain at failure and a delayed and a sharper acceleration of acoustic emission event rate as strain rate is decreased. Here we examine the scaling of such processes in time from laboratory to field conditions using brittle creep (constant stress loading) to failure tests, in an attempt to bridge part of the strain rate gap to natural conditions, and discuss the implications for forecasting the failure time. Dilatancy rate is strongly correlated to strain rate, and decreases to zero in the steady-rate creep phase at strain rates around 10-9 s-1 for a basalt from Mount Etna. The data are well described by a creep model based on the linear superposition of transient (decelerating) and accelerating micro-crack growth due to stress corrosion. The model produces good fits to the failure time in retrospect using the accelerating acoustic emission event rate, but in prospective tests on synthetic data with the same properties we find failure-time forecasting is subject to systematic epistemic and aleatory uncertainties that degrade predictability. The next stage is to use the technology developed to attempt failure forecasting in real time, using live streamed data and a public web-based portal to quantify the prospective forecast quality under such controlled laboratory conditions.

Short Bowel Syndrome

MedlinePlus

... in the intestine hypomotility agents to increase the time it takes food to travel through the intestines, leading to increased nutrient absorption ... dilated segment of the small intestine slow the time it takes for food to travel through the small intestine lengthen the small intestine ...

Racial Variations in Interfacial Behavior of Lipids Extracted from Worn Soft Contact Lenses

PubMed Central

Svitova, Tatyana F.; Lin, Meng C.

2014-01-01

Purpose To explore interfacial behaviors and effect of temperature and dilatation on dynamic properties of multilayered human tear lipids extracted from silicone hydrogel (SiH) lenses worn by asymptomatic Asian and Caucasian subjects. Methods Interfacial properties of lipids extracted from Focus® N&D lenses worn by 14 subjects continuously for 1 month were studied. The lipids were deposited on an air bubble immersed in a model tear electrolytes (MTE) solution to form 100 ± 20 nm-thick films. Surface pressure was recorded during slow expansion/contraction cycles to evaluate compressibility and hysteresis of lipid films. Films were also subjected to fast step-strain dilatations at temperatures 22°–45° C for their visco-elastic properties assessment. Results Iso-cycles for Asian and Caucasian lipids were similar at low surface pressures, but had distinctly different compressibility and hysteresis at dynamic pressures exceeding 30 mN/m. Rheological parameters of reconstituted lipids were also dissimilar between Asian and Caucasian. The elastic modulusE∞ for Caucasian lipids was 1.5 times higher than that for Asian lipids, whereas relaxation time (t) was on average 1.3 times higher for Asian. No significant changes were observed in rheological properties of both Asian and Caucasian lipids when temperature increased from 22.0° to 36.5° C. However, for Caucasian lipids, E∞ reduced considerably at temperatures above 42.0° C, while t remained unchanged. For Asian lipids, both E∞ and t started to decline as temperature increased to 38° C and higher. Conclusions Higher elastic modulus of Caucasian lipids and elasticity threshold at certain deformations indicate stronger structure and intermolecular interactions as compared with more viscous Asian lipids. The differences in interfacial behaviors between Asian and Caucasian lipids may be associated with the differences in their chemical compositions. PMID:24270592

Quantification of annular dilatation and papillary muscle separation in functional mitral regurgitation: role of anterior mitral leaflet length as reference.

PubMed

Jorapur, Vinod; Voudouris, Apostolos; Lucariello, Richard J

2005-07-01

We hypothesized that anterior mitral leaflet length (ALL) does not differ significantly between normal subjects and patients with functional mitral regurgitation (FMR) and hence may be used as a reference measurement to quantify annular dilatation and papillary muscle separation. We prospectively studied 50 controls, 15 patients with systolic left ventricular dysfunction (LVD) with significant FMR, and 15 patients with LVD without significant FMR. Significant MR was defined as an effective regurgitant orifice area > or = 0.2 cm2 as measured by the flow convergence method. Annular diameter, interpapillary distance, and ALL were measured, and the following ratios were derived: annular diameter indexed to ALL (ADI) and interpapillary distance indexed to ALL (IPDI). There was no significant difference in ALL among the three groups. The mean ADI was 1.26 times controls in patients with LVD without significant FMR compared to 1.33 times controls in patients with LVD with significant FMR (P = 0.06, no significant difference between groups). The mean IPDI was 1.42 times controls in patients with LVD without significant FMR compared to 2.1 times controls in patients with LVD with significant FMR (P < 0.0001, significant difference between groups). There was no significant difference in ALL between controls and patients with LVD. ALL can be used as a reference measurement to quantify annular dilatation and papillary muscle separation in patients with FMR. Interpapillary distance but not annular diameter indexed to ALL correlates with severity of FMR.

Temporal evolution of intraocular pressure elevation after pupillary dilation in pigment dispersion syndrome.

PubMed

Jewelewicz, Daniel A; Radcliffe, Nathan M; Liebmann, Jeffrey; Ritch, Robert

2009-03-01

To report 4 patients with pigment dispersion syndrome (PDS) who had delayed intraocular pressure (IOP) spikes after pharmacologic pupillary dilation. Four patients with a diagnosis of PDS with documented IOP spike after pharmacologic pupillary dilation were included. Study patients were examined before and after pupillary dilation. The amount of pigment present in the anterior chamber and the IOP were measured at hourly intervals. Although maximal pigment liberation occurred immediately after maximal dilation, the IOP continued to elevate for at least 1.5 hours. The increase in IOP after pupillary dilation may not occur simultaneously with maximal pigment liberation but may follow it after the pigment has settled out of the anterior chamber. This has implications for monitoring patients with PDS after dilation to detect and treat rises in IOP.

Treatment of benign esophageal stricture by Eder-Puestow or balloon dilators: a comparison between randomized and prospective nonrandomized trials.

PubMed

Yamamoto, H; Hughes, R W; Schroeder, K W; Viggiano, T R; DiMagno, E P

1992-03-01

To determine whether the natural history of strictures is affected by the type of dilator used to treat newly diagnosed peptic strictures, we designed a prospective randomized trial to compare the results after Eder-Puestow or Medi-Tech balloon dilation. We entered 31 patients into the trial. We also prospectively followed up all 92 nonrandomized patients who underwent their first dilation for a benign stricture during the same period as the prospective randomized trial. The nonrandomized patients also underwent dilation with either the Eder-Puestow or the balloon technique at the discretion of the gastroenterologist performing the endoscopy. We found no statistically significant differences in the immediate or long-term results of the two methods among the randomized, nonrandomized, and overall combined groups. All but 1 of the 123 patients had immediate relief of dysphagia. Within each group of patients, the probability of remaining free of dysphagia 1 year after the initial dilation was approximately 20%, and the probability of not requiring a second dilation was approximately 65% with either technique. Major (esophageal rupture) and minor (bleeding or chest pain) complications occurred in 1% and 5% of the patients and 0.4% and 3% of the total dilation procedures, respectively. The esophageal rupture and four of six minor complications occurred after repeated dilations. Five of the six minor complications occurred with use of the Eder-Puestow dilators. We conclude that Eder-Puestow and balloon dilations of benign esophageal strictures are associated with similar outcomes, but repeated dilations and the Eder-Puestow technique may be associated with an increased risk of complications.

Effect of pupillary dilatation on glaucoma assessments using optical coherence tomography

PubMed Central

Smith, Michael; Frost, Andrew; Graham, Christopher Mark; Shaw, Steven

2007-01-01

Aims To examine the effect of pupillary dilatation on the reliability of retinal nerve fibre layer (RNFL) and optic nerve head (ONH) assessments using Stratus OCT in a glaucoma clinic. Methods Observational study of 38 patients attending a glaucoma clinic. The “fast optic disc” and “fast RNFL thickness” programs on Stratus OCT were used to measure the RNFL thickness and ONH cup to disc ratio (CDR). Two scans were done before dilatation and two after dilatation with tropicamide 1% drops. The mean values and reproducibility before and after dilatation were compared, along with the quality of scans as indicated by the “signal strength” score. Results In nine patients (23.7%) no images were obtained undilated but after dilatation examination was possible in all patients. Inability to obtain an undilated scan was associated with smaller pupil size and increasing cataract. The scan quality, as judged by the signal strength score, was higher dilated than undilated for both RNFL thickness (p = 0.011) and ONH CDR (p = 0.007). Reproducibility was higher with dilated scans for RNFL thickness but not for ONH CDR. There were significant differences between the dilated and undilated examinations for three of the five RNFL thickness variables and two of the three ONH CDR categories. Conclusions Acquisition of high quality OCT images was not possible without pupillary dilatation in about 25% of the patients. The dilated scans were more reproducible and of higher quality than the undilated scans. The two methods of examination do not appear to be interchangeable, suggesting that in follow up examinations the pupil should be in the same condition as at baseline. Pupillary dilatation is recommended before glaucoma assessments using Stratus OCT. PMID:17556429

Application of Electrocautery Needle Knife Combined with Balloon Dilatation versus Balloon Dilatation in the Treatment of Tracheal Fibrotic Scar Stenosis.

PubMed

Bo, Liyan; Li, Congcong; Chen, Min; Mu, Deguang; Jin, Faguang

Electrocautery needle knives can largely reduce scar and granulation tissue hyperplasia and play an important role in treating patients with benign stricture. The aim of this retrospective study was to evaluate the efficacy and safety of electrocautery needle knife combined with balloon dilatation versus balloon dilatation alone in the treatment of tracheal stenosis caused by tracheal intubation or tracheotomy. We retrospectively analysed the clinical data of 43 patients with tracheal stenosis caused by tracheotomy or tracheal intubation in our department from January 2013 to January 2016. Among these 43 patients, 23 had simple web-like stenosis and 20 had complex steno sis. All patients were treated under general anaesthesia, and the treatment methods were (1) balloon dilatation alone, (2) needle knife excision of fibrotic tissue combined with balloon dilatation, and (3) needle knife radial incision of fibrotic tissue combined with balloon dilatation. After treatment the symptoms, such as shortness of breath, were markedly improved immediately in all cases. The stenosis degree of patients who were treated with the elec-trocautery needle knife combined with balloon dilatation had better improvement compared with that of those treated with balloon dilatation treatment alone after 3 months (0.45 ± 0.04 vs. 0.67 ± 0.05, p < 0.01), and the proportion of restenosis occurrence that required further treatment was decreased at 6 months (46.9 vs. 81.8%), especially for the web-like stenosis patients, as most of their stenoses dilated with no obvious restenosis and achieved clinical cure. Electrocautery needle knife combined with balloon dilatation is an effective and safe treatment for tracheal fibrotic stenosis compared with balloon dilatation alone. © 2017 S. Karger AG, Basel.

Office-based esophageal dilation in head and neck cancer: Safety, feasibility, and cost analysis.

PubMed

Howell, Rebecca J; Schopper, Melissa A; Giliberto, John Paul; Collar, Ryan M; Khosla, Sid M

2018-02-08

To review experience, safety, and cost of office-based esophageal dilation in patients with history of head and neck cancer (HNCA). The medical records of patients undergoing esophageal dilation in the office were retrospectively reviewed between August 2015 and May 2017. Patients were given nasal topical anesthesia. Next, a transnasal esophagoscopy (TNE) was performed. If the patient tolerated TNE, we proceeded with esophageal dilation using Seldinger technique with the CRE™ Boston Scientific (Boston Scientific Corp., Marlborough, MA) balloon system. Patients were discharged directly from the outpatient clinic. Forty-seven dilations were performed in 22 patients with an average of 2.1 dilations/patient (range 1-10, standard deviation [SD] ± 2.2). Seventeen patients (77%) were male. The average age was 67 years (range 35-78 years, SD ± 8.5). The most common primary site of cancer was oral cavity/oropharynx (n = 10), followed by larynx (n = 6). All patients (100%) had history of radiation treatment. Four patients were postlaryngectomy. The indication for esophageal dilation was esophageal stricture and progressive dysphagia. All dilations occurred in the proximal esophagus. There were no major complications. Three focal, superficial lacerations occurred. Two patients experienced mild, self-limited epistaxis. One dilation was poorly tolerated due to discomfort. One patient required pain medication postprocedure. Office-based esophageal dilation generated $15,000 less in health system charges compared to traditional operating room dilation on average per episode of care. In patients with history of HNCA and radiation, office-based TNE with esophageal dilation appears safe, well-tolerated, and cost-effective. In a small cohort, the technique has low complication rate and is feasible in an otolaryngology outpatient office setting. 4. Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

Computer assisted video analysis of swimming performance in a forced swim test: simultaneous assessment of duration of immobility and swimming style in mice selected for high and low swim-stress induced analgesia.

PubMed

Juszczak, Grzegorz R; Lisowski, Paweł; Sliwa, Adam T; Swiergiel, Artur H

2008-10-20

In behavioral pharmacology, two problems are encountered when quantifying animal behavior: 1) reproducibility of the results across laboratories, especially in the case of manual scoring of animal behavior; 2) presence of different behavioral idiosyncrasies, common in genetically different animals, that mask or mimic the effects of the experimental treatments. This study aimed to develop an automated method enabling simultaneous assessment of the duration of immobility in mice and the depth of body submersion during swimming by means of computer assisted video analysis system (EthoVision from Noldus). We tested and compared parameters of immobility based either on the speed of an object (animal) movement or based on the percentage change in the object's area between the consecutive video frames. We also examined the effects of an erosion-dilation filtering procedure on the results obtained with both parameters of immobility. Finally, we proposed an automated method enabling assessment of depth of body submersion that reflects swimming performance. It was found that both parameters of immobility were sensitive to the effect of an antidepressant, desipramine, and that they yielded similar results when applied to mice that are good swimmers. The speed parameter was, however, more sensitive and more reliable because it depended less on random noise of the video image. Also, it was established that applying the erosion-dilation filtering procedure increased the reliability of both parameters of immobility. In case of mice that were poor swimmers, the assessed duration of immobility differed depending on a chosen parameter, thus resulting in the presence or lack of differences between two lines of mice that differed in swimming performance. These results substantiate the need for assessing swimming performance when the duration of immobility in the FST is compared in lines that differ in their swimming "styles". Testing swimming performance can also be important in the studies investigating the effects of swim stress on other behavioral or physiological parameters because poor swimming abilities displayed by some lines can increase severity of swim stress, masking the between-line differences or the main treatment effects.

Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions.

PubMed

Andersson, Magnus; Lantz, Jonas; Ebbers, Tino; Karlsson, Matts

2015-09-01

Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.

[Competitive sports and dilated cardiomyopathy: the case of a 32-year-old soccer player with ventricular tachycardia].

PubMed

Scharhag, J; Meyer, T; Görge, G; Kindermann, W

2003-01-24

A 32-year-old competitive soccer player presented with palpitations he had felt for 4 weeks during maximal activity (soccer training and match). The physical examination and an exercise electrocardiogram were carried out by his general practitioner up to 19 s at 350 W and a heart rate of 147/min without showing any abnormalities. All blood parameters revealed no signs of illness. During treadmill exercise at a heart rate of 181/min, a non-sustained ventricular tachycardia was induced. Echocardiography showed a dilated left ventricle with an enddiastolic diameter of 70 mm and low fractional shortening (28 %). Cardiac catheterization demonstrated a diminished left ventricular ejection fraction (38 %) and an enlarged enddiastolic volume (199 ml) without signs of coronary artery disease. Electrophysiologic testing induced a non-sustained ventricular tachycardia. The echocardiographic and angiographic results indicated a dilated cardiomyopathy. Competitive sports activities were stopped and treatment with a beta-blocker (metoprolol) and an ACE-antagonist (ramipril) was started. In young male and female athletes, the possibility of severe cardiac abnormalities have to be considered even in the presence of good physical fitness and performance. To reach a high sensitivity for diagnostic ergometry, the work-load must reach the maximal capacity of the cardio-pulmonary system. Differences in the exercise performance of athletes and untrained subjects have to be considered.

A Pathogenetic Classification of Diabetic Macular Edema.

PubMed

Parodi Battaglia, Maurizio; Iacono, Pierluigi; Cascavilla, Marialucia; Zucchiatti, Ilaria; Bandello, Francesco

2018-04-11

The aim of this study was to define a new pathogenetic classification of diabetic macular edema (DME) and to present the results of its application in common clinical practice. One hundred and seventy-seven consecutive patients with center-involving DME, central retinal thickness (CRT) ≥250 µm, were prospectively enrolled. A complete ophthalmological examination included best-corrected visual acuity (BCVA) assessment, fundus photography, and spectral-domain optical coherence tomography (OCT). The DME classification was broken down into 4 categories, combining the presence of retinal thickening with the presence/absence of visible vascular dilations and OCT-detectable macular traction. The OCT parameters included were as follows: CRT, subretinal fluid, intraretinal cysts, and hyper- reflective foci (HF). Four subtypes of DME were identified: vasogenic (131 eyes, DME with vascular dilation), nonvasogenic (46 eyes, DME without vascular dilation), tractional (11 eyes), and mixed DME (13 eyes). Vasogenic DME was the pattern mainly represented in each subclass of CRT (< 300, 300-400, and > 400 µm), with tractional DME observed especially with CRT > 400 µm. Internal and external cysts and a greater presence of hard exudates were predominantly found in vasogenic DME, whereas HF was equally distributed in the 4 DME subgroups. The study offers a new pathogenetic classification able to detect significant differences among DME subtypes. A tailored therapeutic approach could take into consideration specific changes associated with the different DME subtypes. © 2018 S. Karger AG, Basel.

Pneumomediastinum after self-dilation of the esophagus.

PubMed

Noppen, M M; Corne, L; Peters, O; Smekens, L; Musch, W; Vincken, W

1987-10-01

Pneumomediastinum following esophageal perforation is a known complication of Eder Puestow dilation for esophageal stenosis. This is the first reported case of esophageal perforation and pneumomediastinum occurring after instrumental self-dilation of a stenotic esophageal lesion. The observed 0.02 percent perforation rate in this patient (compared to the reported 0.3 percent in Eder Puestow "hetero"-dilation) makes the Eder Puestow auto-dilation procedure seem justifiable in a well-trained and well-informed patient.

Evaluation of changes in left ventricular structure and function in hypertensive patients with coronary artery disease after PCI using real-time three-dimensional echocardiography.

PubMed

Meng, Yanhong; Zong, Ling; Zhang, Ziteng; Han, Youdong; Wang, Yanhui

2018-02-01

We aimed to evaluate the changes in left ventricular structure and function in hypertensive patients with coronary artery disease before and after percutaneous coronary intervention (PCI) using real-time three-dimensional echocardiography. Two hundred and eighty hypertensive patients with coronary artery disease undergoing PCI and 120 cases who did not receive PCI in our hospital were selected as the subjects of our study. All patients were administered with routine antiplatelet, anticoagulant, lipid-lowering, antihypertensive, dilating coronary artery and other medications. The left ventricular systolic function and systolic synchrony index changes before and after subjects were treated by PCI were analyzed using three-dimensional echocardiography. At 2 days before surgery, there were no significant differences in the left ventricular end-diastolic volume, left ventricular end-systolic volume (LVESV) and ejection fraction (EF) between the two patient groups (P>0.05). At 3 months and 9 months, the two key time points after PCI, the LVESV level in the PCI group was distinctly decreased, while EF was significantly increased (P<0.05). In addition, before treatment, there were no significant differences in the parameters of time from the corresponding segment of the myocardium to the minimal systolic volume in two patient groups, such as Tmsv-16SD, Tmsv-16Dif, Tmsv-12SD, Tmsv-12Dif, Tmsv-6SD and Tmsv-6Dif (P>0.05); however, the parameters of time from the corresponding segment of the myocardium to the minimal systolic volume in patients in the PCI group were significantly reduced at 3 and 9 months after surgery (P<0.05). Three-dimensional echocardiography can evaluate the critical parameters in the prognosis of hypertensive patients with coronary artery disease after PCI accurately and in real-time, which may play a significant role.

Evaluation of an alternative treatment protocol by aglepristone to induce parturition in ewes with an experimental model of early pregnancy toxemia.

PubMed

Özalp, G R; Yavuz, A; Seker, I; Udum-Küçükşen, D; Rişvanlı, A; Korlu, Y

2018-05-04

A new protocol with aglepristone to induce parturition in ewes with pregnancy toxemia has been reported in the present manuscript. Four experimental groups were defined: Group AG5 (n = 10), Group DEX (n = 10), Group NC (n = 5) and Group PT (n = 5) in which ewes were injected twice with 10 mg/kg of aglepristone and 5 ml dexamethasone in first two groups, respectively; whereas negative control and pregnancy toxemia groups received no treatment for parturition induction. Different clinical parameters associated with parturition in ewes and their newborns were investigated. Blood hematology and biochemical measurements were carried out both in ewes and lambs. Blood pH values of lambs were recorded during the study. The injection time-lambing time, injection time-vaginal discharge intervals, placental expulsion periods, placental weight and vaginal delivery interval between lambs, hematological and biochemical results were not statistically different among the groups (p > 0,05). Increased NEFA and β-HBA concentrations accompanied the disease and all ewes in AG, DEX and PT Groups developed clinical pregnancy toxemia (NEFA; P = 0,009) and β-HBA; (P = 0,039). The differences in rectal body temperature of lambs were not significant (p > 0,05), whereas birth weight was found statistically significant among groups (p < 0,05). Blood pH, biochemical and hematologic measurements of lambs had also significant differences depending on different time points. Parturition pathology by means of incomplete cervical dilatation was severely observed in DEX Group. The results of this study show that aglepristone application in pregnancy toxemia to induce parturition could precisely control lambing time without any side effects in either mothers or lambs. Apart from these, it could be speculated that dexamethasone seems to induce parturition causing crucial pathologies, which results in important and risky changes in newborns' life. Incomplete cervical dilatation and continued ineffective uterine contractions could be a major factor of newborn losses because of placental separation and cessation of blood supply. Copyright © 2018 Elsevier Inc. All rights reserved.

Cardiomyocyte hypertrophy, oncosis, and autophagic vacuolization predict mortality in idiopathic dilated cardiomyopathy with advanced heart failure.

PubMed

Vigliano, Carlos A; Cabeza Meckert, Patricia M; Diez, Mirta; Favaloro, Liliana E; Cortés, Claudia; Fazzi, Lucía; Favaloro, Roberto R; Laguens, Rubén P

2011-04-05

The aim of this study was to identify the remodeling parameters cardiomyocyte (CM) damage or death, hypertrophy, and fibrosis that may be linked to outcomes in patients with advanced heart failure (HF) in an effort to understand the pathogenic mechanisms of HF that may support newer therapeutic modalities. There are controversial results on the influence of fibrosis, CM hypertrophy, and apoptosis on outcomes in patients with HF; other modalities of cell damage have been poorly investigated. In endomyocardial biopsy specimens from 100 patients with idiopathic dilated cardiomyopathy and advanced HF, CM diameter and the extent of fibrosis were determined by morphometry. The proportion of CMs with evidence of apoptosis, autophagic vacuolization (AuV), and oncosis was investigated by immunohistochemical methods and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. Those parameters were correlated with mortality in 3 years of follow-up by univariate analysis and with multivariate models incorporating the clinical variables more relevant to the prediction of outcomes. CM AuV occurred in 28 patients (0.013 ± 0.012%) and oncosis in 41 (0.109 ± 0.139%). Nineteen patients showed both markers. Apoptotic CM nuclei were observed in 3 patients. In univariate analysis, CM diameter and AuV, either alone or associated with oncosis, were predictors of mortality. In multivariate analysis, CM diameter (hazard ratio: 1.37; 95% confidence interval: 1.12 to 1.68; p = 0.002) and simultaneous presence in the same endomyocardial biopsy specimen of AuV and oncosis (hazard ratio: 2.82; 95% confidence interval: 1.12 to 7.13; p = 0.028) were independent predictors of mortality. CM hypertrophy and AuV, especially in association with oncosis, are predictors of outcome in patients with idiopathic dilated cardiomyopathy and severe HF. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Pupil Dilation to Explicit and Non-Explicit Sexual Stimuli.

PubMed

Watts, Tuesday M; Holmes, Luke; Savin-Williams, Ritch C; Rieger, Gerulf

2017-01-01

Pupil dilation to explicit sexual stimuli (footage of naked and aroused men or women) can elicit sex and sexual orientation differences in sexual response. If similar patterns were replicated with non-explicit sexual stimuli (footage of dressed men and women), then pupil dilation could be indicative of automatic sexual response in fully noninvasive designs. We examined this in 325 men and women with varied sexual orientations to determine whether dilation patterns to non-explicit sexual stimuli resembled those to explicit sexual stimuli depicting the same sex or other sex. Sexual orientation differences in pupil dilation to non-explicit sexual stimuli mirrored those to explicit sexual stimuli. However, the relationship of dilation to non-explicit sexual stimuli with dilation to corresponding explicit sexual stimuli was modest, and effect magnitudes were smaller with non-explicit sexual stimuli than explicit sexual stimuli. The prediction that sexual orientation differences in pupil dilation are larger in men than in women was confirmed with explicit sexual stimuli but not with non-explicit sexual stimuli.

Malignant Esophagogastric Junction Obstruction: Efficacy of Balloon Dilation Combined with Chemotherapy and/or Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ko, Gi-Young; Song, Ho-Young, E-mail: hysong@amc.seoul.kr; Hong, Heuk-Jin

2003-04-15

Purpose: To assess the efficacy of balloon dilation combined with chemotherapy and/or radiation therapy for palliation of dysphagia due to malignant esophagogastric junction strictures. Methods: Fluoroscopically guided balloon dilation was attempted in 20 patients. The causes of strictures were gastric adenocarcinoma (n = 10) and esophageal squamous cell carcinoma (n = 10). Scheduled chemotherapy and/or radiation therapy followed balloon dilation in all patients. Results: There were no technical failures or major complications. After balloon dilation, 15 (75%) patients showed improvement of dysphagia. No patient complained of reflux esophagitis during the follow-up period. Among the 15 patients, seven needed no furthermore » treatment for palliation of dysphagia until their deaths. The remaining eight patients underwent repeat balloon dilation(n = 4) or stent placement (n = 4)3-43 weeks (mean 15 weeks) after the initial balloon dilation because of recurrent dysphagia. Conclusion: Balloon dilation combined with chemotherapy and/or radiation therapy seems to be an easy and reasonably effective palliative treatment for malignant esophagogastric strictures.« less

A prosthesis for banding the main pulmonary artery, capable of serial dilatation by balloon angioplasty.

PubMed

Vince, D J; Culham, J A

1989-03-01

A prosthesis constructed with a fatigued steel helix encased in a silicone rubber shield was used to band the main pulmonary artery in 10 dogs. After a mean duration of 138 days the banded site was dilated with a 20 mm diameter angioplasty catheter. This dilatation produced a mean increase of 44.3% in the cross-sectional area. A further mean increase of 2.2% in the cross-sectional area was measured 137 days after the dilatation. In five uncomplicated experiments a second dilatation was performed with a 23 mm diameter angioplasty catheter after a mean interval of 140 days. The second dilatation produced a further 21% increase in the cross-sectional area. In the five experiments in which two dilatations were performed, there was a total increase in the mean cross-sectional area of 94% produced 273 days after banding. This prosthesis maintains banding of the main pulmonary artery and can be serially dilated by balloon angioplasty.

Application of impulse oscillometry and bronchial dilation test for analysis in patients with asthma and chronic obstructive pulmonary disease

PubMed Central

Li, Yueyue; Chen, Yang; Wang, Ping

2015-01-01

Impulse oscillometry (IOS) is a good method for measuring airway resistance. The aim of this study was to assess the diagnostic contribution of IOS combined with bronchial dilation test (BDT) when distinguishing between patients with asthma and those with chronic obstructive pulmonary disease (COPD). 870 were enrolled in the study including 561 patients with asthma, 100 patients with COPD and 209 patients with chronic coughing or normal subjects. All the participants underwent routine pulmonary function tests, IOS and BDT examination. And IOS examination was before and after BDT. IOS parameters (R5, R20, R25, R35, X5, X20, X25, X35, Fres, Zrs & RP) and forced expiratory volume in one second (FEV1) were recorded. Receiver operating characteristics (ROC) curve analysis was performed to evaluate the diagnostic ability to differentiate asthma and COPD. The discriminative power of the various parameters studied was determined by means of ROC curves: the area under the curve (AUC), sensitivity and specificity. The X5, X20, X25, X35, Fres, Zrs and Rp correlated better with COPD. In particular, X5, Fres and X25 have been found to be significantly correlated with COPD. The diagnostic efficiency of X5, Fres and X25 when diagnosis COPD, expressed by ROC curve parameters, was as follows: AUC (0.725, 0.730, 0.724), sensitivity (67%, 77%, 83%) and specificity (68%, 65%, 58%), respectively. The diagnostic efficiency of Zrs, R5 and X35 when diagnosis asthma, expressed by ROC curve parameters, was as follows: AUC (0.721, 0.710, 0.695), sensitivity (62%, 72%, 53%) and specificity (72%, 61%, 76%), respectively. Our findings show, that X5, X25 and Fres may be useful for predictions and evaluations for COPD. And R5, X35 and Zrs may provide useful IOS parameters for asthma. IOS combined BDT could be useful diagnostic and differential diagnosis between asthma and COPD. PMID:25785124

Application of impulse oscillometry and bronchial dilation test for analysis in patients with asthma and chronic obstructive pulmonary disease.

PubMed

Li, Yueyue; Chen, Yang; Wang, Ping

2015-01-01

Impulse oscillometry (IOS) is a good method for measuring airway resistance. The aim of this study was to assess the diagnostic contribution of IOS combined with bronchial dilation test (BDT) when distinguishing between patients with asthma and those with chronic obstructive pulmonary disease (COPD). 870 were enrolled in the study including 561 patients with asthma, 100 patients with COPD and 209 patients with chronic coughing or normal subjects. All the participants underwent routine pulmonary function tests, IOS and BDT examination. And IOS examination was before and after BDT. IOS parameters (R5, R20, R25, R35, X5, X20, X25, X35, Fres, Zrs & RP) and forced expiratory volume in one second (FEV1) were recorded. Receiver operating characteristics (ROC) curve analysis was performed to evaluate the diagnostic ability to differentiate asthma and COPD. The discriminative power of the various parameters studied was determined by means of ROC curves: the area under the curve (AUC), sensitivity and specificity. The X5, X20, X25, X35, Fres, Zrs and Rp correlated better with COPD. In particular, X5, Fres and X25 have been found to be significantly correlated with COPD. The diagnostic efficiency of X5, Fres and X25 when diagnosis COPD, expressed by ROC curve parameters, was as follows: AUC (0.725, 0.730, 0.724), sensitivity (67%, 77%, 83%) and specificity (68%, 65%, 58%), respectively. The diagnostic efficiency of Zrs, R5 and X35 when diagnosis asthma, expressed by ROC curve parameters, was as follows: AUC (0.721, 0.710, 0.695), sensitivity (62%, 72%, 53%) and specificity (72%, 61%, 76%), respectively. Our findings show, that X5, X25 and Fres may be useful for predictions and evaluations for COPD. And R5, X35 and Zrs may provide useful IOS parameters for asthma. IOS combined BDT could be useful diagnostic and differential diagnosis between asthma and COPD.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Woong Hee; Kim, Jin Hyoung, E-mail: m1fenew@daum.net; Park, Jung-Hun

Purpose: Little was known about the safety and long-term efficacy of fluoroscopically guided balloon dilation for postintubation tracheal stenosis. The purpose of this study was to evaluate the safety and long-term efficacy of fluoroscopically guided balloon dilation in patients with postintubation tracheal stenosis. Methods: From February 2000 to November 2010, 14 patients underwent fluoroscopically guided balloon dilation for postintubation tracheal stenosis. Technical success, clinical success, and complications were evaluated. Patients were followed up for recurrent symptoms. Results: In all patients, fluoroscopically guided balloon dilation was technically and clinically successful with no major complications. Following the initial procedure, six patients (43more » %) remained asymptomatic during a follow-up period. Obstructive symptoms recurred in eight patients (57 %) within 6 months (mean, 1.7 months), who were treated with repeat balloon dilation (n = 4) and other therapies. Of the four patients who underwent repeat balloon dilation, three became asymptomatic. One patient became asymptomatic after a third balloon dilation. On long-term (mean, 74 months) follow-up, 71 % of patients experienced relief of symptoms following fluoroscopically guided balloon dilation. Conclusions: Fluoroscopically guided balloon dilation may be safe, is easy to perform, and resulted in effective treatment in patients with postintubation tracheal stenosis.« less

Psoriasis and dilated cardiomyopathy: coincidence or associated diseases?

PubMed

Eliakim-Raz, Noa; Shuvy, Mony; Lotan, Chaim; Planer, David

2008-01-01

Psoriasis is a common immune-mediated disease which affects 1-3% of the population. The etiology of psoriasis is unknown. Idiopathic dilated cardiomyopathy is probably the end result of a variety of toxic, metabolic or infectious agents. During a computerized search for cardiomyopathy among all patients hospitalized with psoriasis in the Hadassah University Hospital since 1980 we found an increased prevalence of cardiomyopathy, and specifically dilated cardiomyopathy. We present 4 patients who suffer from both conditions. In accordance with previous data, an association between preexisting psoriasis and dilated cardiomyopathy is suggested. We suggest that the genetic risk factors of dilated cardiomyopathy are shared by psoriasis, and more specifically psoriatic arthritis. Alternatively, the immune reaction that is triggered in dilated cardiomyopathy leading to the progression of the disease might be enhanced in patients with psoriasis or psoriatic arthritis. Chronic inflammation and persistent secretion of proinflammatory cytokines may be considered a potential pathway, triggering the initiation and progression of dilated cardiomyopathy in psoriatic patients. Further investigation of the genetic and immune risk factors involved in dilated cardiomyopathy and in psoriasis may lead to a better understanding of the pathogenesis and treatment of dilated cardiomyopathy. Copyright 2008 S. Karger AG, Basel.

Fluoroscopically guided large balloon dilatation for treating congenital esophageal stenosis in children.

PubMed

Hu, Hong-Tao; Shin, Ji Hoon; Kim, Jin-Hyoung; Jang, Jong Keon; Park, Jung-Hoon; Kim, Tae-Hyung; Nam, Deok Ho; Song, Ho-Young

2015-07-01

We aimed to evaluate the safety and clinical effectiveness of fluoroscopically guided large balloon dilatation for treating congenital esophageal stenosis in children. Our study included seven children (mean age 4.0 years) who underwent a total of ten balloon dilatation sessions. The initial balloon diameters were 10-15 mm. The technical success, clinical success (improved food intake and reduced dysphagia within 1 month following the first balloon dilatation), dysphagia recurrence, and complications were retrospectively evaluated. Technical and clinical success rates were 100 %. During the mean 38-month follow-up period after the first balloon dilatation, 3 (43 %) patients underwent only one additional balloon dilatation 4-5 months after the first balloon dilatation for dysphagia recurrence. Two of them showed improvement without further recurrence, while the remaining one underwent partial esophagectomy. Well-contained transmural esophageal rupture (type 2) occurred in two (29 %, 2/7) patients and during two (20 %, 2/10) balloon dilatation sessions. All ruptures were successfully treated conservatively. Our study showed that fluoroscopically guided large balloon dilatation seems to be a simple and effective primary treatment technique for congenital esophageal stenosis in children. Esophageal ruptures were not uncommon although they were not fatal.

Task-evoked pupillometry provides a window into the development of short-term memory capacity

PubMed Central

Johnson, Elizabeth L.; Miller Singley, Alison T.; Peckham, Andrew D.; Johnson, Sheri L.; Bunge, Silvia A.

2014-01-01

The capacity to keep multiple items in short-term memory (STM) improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.6 years) and adults (n = 54, mean age = 27.5 years) performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC) and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM overload task, after which the adults' pupils continued to dilate and the children's began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM. PMID:24659980

Pupil size tracks perceptual content and surprise.

PubMed

Kloosterman, Niels A; Meindertsma, Thomas; van Loon, Anouk M; Lamme, Victor A F; Bonneh, Yoram S; Donner, Tobias H

2015-04-01

Changes in pupil size at constant light levels reflect the activity of neuromodulatory brainstem centers that control global brain state. These endogenously driven pupil dynamics can be synchronized with cognitive acts. For example, the pupil dilates during the spontaneous switches of perception of a constant sensory input in bistable perceptual illusions. It is unknown whether this pupil dilation only indicates the occurrence of perceptual switches, or also their content. Here, we measured pupil diameter in human subjects reporting the subjective disappearance and re-appearance of a physically constant visual target surrounded by a moving pattern ('motion-induced blindness' illusion). We show that the pupil dilates during the perceptual switches in the illusion and a stimulus-evoked 'replay' of that illusion. Critically, the switch-related pupil dilation encodes perceptual content, with larger amplitude for disappearance than re-appearance. This difference in pupil response amplitude enables prediction of the type of report (disappearance vs. re-appearance) on individual switches (receiver-operating characteristic: 61%). The amplitude difference is independent of the relative durations of target-visible and target-invisible intervals and subjects' overt behavioral report of the perceptual switches. Further, we show that pupil dilation during the replay also scales with the level of surprise about the timing of switches, but there is no evidence for an interaction between the effects of surprise and perceptual content on the pupil response. Taken together, our results suggest that pupil-linked brain systems track both the content of, and surprise about, perceptual events. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Sonographic evaluation of the bladder neck in continent and stress-incontinent women.

PubMed

Schaer, G N; Perucchini, D; Munz, E; Peschers, U; Koechli, O R; Delancey, J O

1999-03-01

To evaluate a new sonographic method to measure depth and width of proximal urethral dilation during coughing and Valsalva maneuver and to report its use in a group of stress-incontinent and continent women. Fifty-eight women were evaluated, 30 with and 28 without stress incontinence proven urodynamically, with a bladder volume of 300 mL and the subjects upright. Urethral pressure profiles at rest were performed with a 10 French microtip pressure catheter. Bladder neck dilation and descent were assessed by perineal ultrasound (5 MHz curved linear array transducer) with the help of ultrasound contrast medium (galactose suspension-Echovist-300), whereas abdominal pressure was assessed with an intrarectal balloon catheter. Statistical analysis used the nonparametric Mann-Whitney test. The depth and diameter of urethral dilation could be measured in all women. During Valsalva, all 30 incontinent women exhibited urethral dilation. One incontinent woman showed dilation only while performing a Valsalva maneuver, not during coughing. In the continent group, 12 women presented dilation during Valsalva and six during coughing. In continent women, dilation was visible only in those who were parous. Nulliparous women did not have dilation during Valsalva or coughing. Bladder neck descent was visible in continent and incontinent women. This method permits quantification of depth and diameter of bladder neck dilation, showing that both incontinent and continent women might have bladder neck dilation and that urinary continence can be established at different locations along the urethra in different women. Parity seems to be a main prerequisite for a proximal urethral defect with bladder neck dilation.

Intrapulmonary vascular dilatation evaluated by 99mTc-MAA scintigraphy and its association with portal hypertension in schistosomiasis.

PubMed

Queirós, Andréa Simone Siqueira de; Brandão, Simone Cristina Soares; Domingues, Ana Lúcia Coutinho; Macedo, Liana Gonçalves; Ourem, Maira Souto; Lopes, Edmundo Pessoa Almeida

2014-06-01

Portal hypertension is responsible for various complications in patients with schistosomiasis, among them intrapulmonary vascular dilations (IPVD). In cirrhotic patients the presence of IPVD is a sign of poor prognosis, but in patients with hepatosplenic schistosomiasis (HSS) there are no studies assessing the significance of this change. The aim of this study was to evaluate the occurrence of IPVD through 99mTc-MAA scintigraphy in patients with HSS and its relationship with clinical, laboratory, endoscopic and ultrasound parameters. Cross-sectional study evaluating 51 patients with HSS. Patients were diagnosed with IPVD when the brain uptake of 99mTc-MAA was higher than 6%. Subsequently, they were divided according to presence (G1) or absence (G2) of IPVD and variables were compared between groups. Overall, 51 patients with mean age of 56±12 years were assessed. IPVD was observed in 31 patients (60%). There was no statistically significant differences between groups when clinical, laboratory and endoscopic parameters were compared. Regarding ultrasound parameters, the splenic vein diameter was smaller in G1 (0.9 ± 0.3 cm) compared to G2 (1.2 ± 0.4 cm), p=0.029. In patients with HSS, the occurrence of IPVD by 99mTc-MAA scintigraphy was high and was associated with lower splenic vein diameter, which can be a mechanism of vascular protection against portal hypertension. However, more studies are needed to determine the clinical significance of the early diagnosis and natural evolution of IPVD in this population.

What's Cardiomyopathy

MedlinePlus

... another over time. According to the pediatric cardiomyopathy survey, dilated cardiomyopathy is the most common (58%), followed ... and are replaced by fatty tissue. In the early stages of the disease, the right side of ...

Traumatic tracheobronchial stricture treated with the Eder-Puestow dilator.

PubMed

Erichsen, H G

1980-09-01

A case of tracheobronchial stenosis secondary to trauma is presented. Primary reconstruction resulted in stricture in the distal part of the trachea. Resection and anastomosis was followed by restenosis, which had to be treated endoscopically. Endobronchial resections and forceful dilatations with stiff bronchoscopes were done weekly for about 11 months without lasting benefit. After changing to Eder-Puestow dilators, the dilatations could be done at steadily increasing intervals. This method of dilatation was found to be safe, effective and less traumatic.

False Labor at Term in Singleton Pregnancies: Discharge After a Standardized Assessment and Perinatal Outcomes.

PubMed

Nelson, David B; McIntire, Donald D; Leveno, Kenneth J

2017-07-01

To evaluate perinatal outcomes in women sent home with a diagnosis of false labor at term and assess the time interval to return for delivery. This was a prospective observational cohort study of women at 37 0/7 to 41 6/7 weeks of gestation without pre-existing medical complications who presented to our hospital-based triage unit with symptoms of labor and underwent a standardized evaluation. Women diagnosed as having false labor with a live singleton fetus in cephalic presentation without a prior cesarean delivery and sent home were compared with a group of similar women diagnosed to be in spontaneous labor. Women with hypertension, diabetes, and known fetal malformations were excluded. Using a perinatal composite outcome of respiratory insufficiency, intraventricular hemorrhage, culture-proven sepsis, Apgar score 3 or less at 5 minutes, phototherapy, and perinatal death, we tested the noninferiority of being sent home compared with being admitted for labor. The relationship of cervical dilatation to the time interval from discharge home to delivery was also analyzed. Between October 2012 and March 2016, a total of 3,949 women met inclusion criteria and were diagnosed with false labor, discharged, and returned to deliver, whereas 2,592 similar women were admitted in early labor. The mean interval from discharge to return was 4.9 days. Cesarean delivery rates were not different between the study groups-11% for both (P=.69), and the perinatal composite outcome rates were not significantly different between those sent home and those admitted-3.2% compared with 3.1% (P=.79). Women with more advanced cervical dilatation at discharge returned and delivered significantly earlier than those with less dilatation regardless of parity. Discharge with false labor at term after a standardized assessment in a triage unit was not associated with increased rates of adverse perinatal composite outcomes or cesarean delivery. The time interval to return for delivery was significantly associated with the cervical dilatation at discharge.

Impact of prior interventions on outcomes during per oral endoscopic myotomy.

PubMed

Louie, Brian E; Schneider, Andreas M; Schembre, Drew B; Aye, Ralph W

2017-04-01

Per oral endoscopic myotomy (POEM) is performed by accessing the submucosal space of the esophagus. This space may be impacted by prior interventions such as submucosal injections, dilations or previous myotomies. These interventions could make POEM more difficult and may deter surgeons during their initial experience. We sought to determine the impact of prior interventions on our early experience. Prospective, single-center study of consecutive patients undergoing POEM. Patients were grouped according to their anticipated complexity: Group A: no prior interventions (N = 19); Group B: prior interventions such as submucosal injections and/or dilations (N = 11) and  Group C: sigmoidal esophagus, prior esophageal surgery, balloon dilation >30 mm (N = 8). We compared operative times, inadvertent mucosotomy rates, complications and short-term outcomes between groups. A total of 38 patients underwent POEM for achalasia subtypes: I (N = 9), II (N = 19) and III (N = 7). Three had other dysmotility disorders. Patients between the groups were similar. Operative times were similar between Group A and Group B but significantly longer for Group C (133 vs. 132 vs. 210 min, p = 0.001). Mucosotomy rates were highest in Group A (6/19) with 1 each in Group B/C (p = 0.46). One patient in Group A required an esophageal stent. Eckardt scores improved in all groups (6-1; 8-2; 6-0.5, p = 0.73), and postoperative GERD-HRQL scores were similar. One patient underwent laparoscopic myotomy for persistent symptoms with no improvement, and one patient underwent esophagectomy for a sigmoid esophagus and persistent symptoms despite adequate myotomy. A prior intervention does not seem to impact short-term clinical outcomes with POEM. Patients who had submucosal injections or small caliber dilations are similar to patients with no prior inventions; however, patients with a sigmoid-shaped esophagus and/or a prior myotomy require nearly double the operative time. Endoscopists undertaking POEM should consider these during their learning curve.

Application of improved wavelet total variation denoising for rolling bearing incipient fault diagnosis

NASA Astrophysics Data System (ADS)

Zhang, W.; Jia, M. P.

2018-06-01

When incipient fault appear in the rolling bearing, the fault feature is too small and easily submerged in the strong background noise. In this paper, wavelet total variation denoising based on kurtosis (Kurt-WATV) is studied, which can extract the incipient fault feature of the rolling bearing more effectively. The proposed algorithm contains main steps: a) establish a sparse diagnosis model, b) represent periodic impulses based on the redundant wavelet dictionary, c) solve the joint optimization problem by alternating direction method of multipliers (ADMM), d) obtain the reconstructed signal using kurtosis value as criterion and then select optimal wavelet subbands. This paper uses overcomplete rational-dilation wavelet transform (ORDWT) as a dictionary, and adjusts the control parameters to achieve the concentration in the time-frequency plane. Incipient fault of rolling bearing is used as an example, and the result shows that the effectiveness and superiority of the proposed Kurt- WATV bearing fault diagnosis algorithm.

Dilatancy Criteria for Salt Cavern Design: A Comparison Between Stress- and Strain-Based Approaches

NASA Astrophysics Data System (ADS)

Labaune, P.; Rouabhi, A.; Tijani, M.; Blanco-Martín, L.; You, T.

2018-02-01

This paper presents a new approach for salt cavern design, based on the use of the onset of dilatancy as a design threshold. In the proposed approach, a rheological model that includes dilatancy at the constitutive level is developed, and a strain-based dilatancy criterion is defined. As compared to classical design methods that consist in simulating cavern behavior through creep laws (fitted on long-term tests) and then using a criterion (derived from short-terms tests or experience) to determine the stability of the excavation, the proposed approach is consistent both with short- and long-term conditions. The new strain-based dilatancy criterion is compared to a stress-based dilatancy criterion through numerical simulations of salt caverns under cyclic loading conditions. The dilatancy zones predicted by the strain-based criterion are larger than the ones predicted by the stress-based criteria, which is conservative yet constructive for design purposes.

The relationship between gastrointestinal motility and gastric dilatation-volvulus in dogs.

PubMed

Gazzola, Krista M; Nelson, Laura L

2014-09-01

Gastric dilatation-volvulus (GDV) is a devastating disease that most commonly affects large and giant-breed dogs. Though a number of risk factors have been associated with the development of GDV, the etiology of GDV remains unclear. Abnormal gastric motility patterns and delayed gastric emptying have been previously described in dogs following GDV. Work evaluating the effects of gastropexy procedures and changes to gastric motility after experimental GDV has not found the same changes as those found in dogs with naturally occurring GDV. Although the role of abnormal gastric motility in dogs with GDV will need to be clarified with additional research, such study is likely to be facilitated by improved access to and development of noninvasive measurement techniques for the evaluation of gastric emptying and other motility parameters. In particular, the availability of Food and Drug Administration-approved wireless motility devices for the evaluation of gastrointestinal motility is particularly promising in the study of GDV and other functional gastrointestinal diseases of large and giant-breed dogs. Published by Elsevier Inc.

Recurrent epistaxis from Kiesselbach area syndrome in patients suffering from hemorrhoids: fact or fiction?

PubMed

Mladina, Ranko; Cavcic, Josip; Subaric, Marin

2002-01-01

It has been found that >90% of patients suffering from recurrent epistaxis from Kiesselbach area syndrome (REKAS) simultaneously suffered from hemorrhoids. To clarify this, the authors decided to investigate in the opposite direction, i.e., to find out whether or not REKAS occurs in patients suffering primarily from hemorrhoids. The study group included 53 randomly selected hospitalized patients with hemorrhoidal disorder (31 males and 22 females: age range 18-57 years). A search for essential clinical signs of REKAS was performed in each patient. Incidence was not high, although all clinical parameters were nearly the same: dilated vessels in Kiesselbach venous plexus (83.01%) and a positive hereditary factor (92.7%). The only missing factor in patients with hemorrhoids was anterior septal deformity, so frequent in REKAS patients. CONCLUSIONS; The authors conclude that REKAS and hemorrhoidal syndrome are separate clinical entities that are characterized by dilated vessels of similar venous plexus and simultaneous appearance in the same patient or close relatives.

Focal dilation and paradoxical collapse of cortical fissures and sulci in patients with normal-pressure hydrocephalus.

PubMed

Holodny, A I; George, A E; de Leon, M J; Golomb, J; Kalnin, A J; Cooper, P R

1998-11-01

The authors describe a subgroup of patients with shunt-proven normal-pressure hydrocephalus (NPH) who presented with focal fissural and sulcal dilation on imaging studies. The specific radiological features and methods of differentiating this condition from cortical atrophy are delineated. Normal-pressure hydrocephalus has been described as dilation of the ventricles that is out of proportion to the sulci. Sulcal dilation has been taken as evidence of cortical atrophy and has even been used as a criterion to exclude patients from undergoing a shunting procedure. The authors describe five cases of patients with shunt-proven NPH who presented with focal dilation of cortical fissures and sulci. In three of the cases, there was a paradoxical decrease in the size of the dilated fissures and sulci that paralleled the decrease in the size of the lateral ventricles following successful shunting. This study demonstrates that focal fissural and sulcal dilation may represent reservoirs of cerebrospinal fluid analogous to the ventricular system. Patients should not be denied a shunting procedure solely on the basis of focally dilated fissures of sulci.

[Endoscopic contribution in the dilatation of caustic esophagus stenosis].

PubMed

Seydou, Togo; Abdoulaye, Ouattara Moussa; Xing, Li; Zi, Sanogo Zimogo; Sekou, Koumaré; Wen, Yang Shang; Ibrahim, Sankare; Sekou, Toure Cheik Ahmed; Boubacar, Maiga Ibrahim; Saye, Jacque; Jerome, Dakouo Dodino; Dantoumé, Toure Ousmane; Sadio, Yena

2016-01-01

The aim of this work was to present the contribution of the endoscopy in the management of esophageal dilatation for caustic esophageal stenosis (CES). This was a descriptive and prospective study in the thoracic surgery department at the Hospital of Mali. A total of 46 cases of CES is recorded and divided into 4 groups according to the topography of the esophageal lesions. For the different methods of dilatation the number of performed endoscopic support was determined to understand the contribution of endoscopic means in the success of dilatation for CES. The outcome, complications and mortality in the two methods were compared. Fibroscopy was used in 41.30% of patients with Savary Guillard dilators and in 47.82% of patients with Lerut dilators. Video laryngoscopy was used in 58.69% of patients who underwent dilatation with Lerut dilators. The passage of the guide wire was performed in 39.13% under video laryngoscopy and 58.68% under fibroscopy. In comparison of the two methods, there is a significant difference in the occurrence of complications (p=0.04075), general anesthesia (p=0.02287), accessibility (p=0.04805) and mortality (p=0.00402). The CES is a serious disease and under evaluated in Mali. The endoscopies contribute significantly to the success of esophageal dilatation for caustic stenosis in the different methods we used.

Health-Care Utilization and Complications of Endoscopic Esophageal Dilation in a National Population

PubMed Central

Goyal, Abhinav; Chatterjee, Kshitij; Yadlapati, Sujani; Singh, Shailender

2017-01-01

Background/Aims Esophageal stricture is usually managed with outpatient endoscopic dilation. However, patients with food impaction or failure to thrive undergo inpatient dilation. Esophageal perforation is the most feared complication, and its risk in inpatient setting is unknown. Methods We used National Inpatient Sample (NIS) database for 2007–2013. International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) codes were used to identify patients with esophageal strictures. Logistic regression was used to assess association between hospital/patient characteristics and utilization of esophageal dilation. Results There were 591,187 hospitalizations involving esophageal stricture; 4.2% were malignant. Endoscopic dilation was performed in 28.7% cases. Dilation was more frequently utilized (odds ratio [OR], 1.36; p<0.001), had higher in-hospital mortality (3.1% vs. 1.4%, p<0.001), and resulted in longer hospital stays (5 days vs. 4 days, p=0.01), among cases of malignant strictures. Esophageal perforation was more common in the malignant group (0.9% vs. 0.5%, p=0.007). Patients with malignant compared to benign strictures undergoing dilation were more likely to require percutaneous endoscopic gastrostomy or jejunostomy (PEG/J) tube (14.1% vs. 4.5%, p<0.001). Palliative care services were utilized more frequently in malignant stricture cases not treated with dilation compared to those that were dilated. Conclusions Inpatient endoscopic dilation was utilized in 29% cases of esophageal stricture. Esophageal perforation, although infrequent, is more common in malignant strictures. PMID:28301921

Nitroglycerin mediated dilation evaluated by ultrasound is associated with sTWEAK in hemodialysis patients.

PubMed

Rusu, Crina Claudia; Ghervan, Liviu; Racasan, Simona; Kacsa, Ina; Moldovan, Diana; Potra, Alina; Bondor, Cosmina; Anton, Florin; Patiu, Ioan Mihai; Caprioara, Mirela Gherman

2016-03-01

The main cause of death in hemodialysis (HD) patients is cardiovascular disease. Ultrasound assessment of the brachial artery dysfunction is easily achievable and can non-invasively detect atherosclerosis in various stages. In HD patients the cardiovascular risk profile is different and the determinants of brachial arterial function can be distinct comparing with general population. The aim of the study is to assess the determinants of arterial brachial function (flow-mediated and nitroglycerin-mediated dilation) evaluated by ultrasound in HD patients and their relation with tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) described as atherosclerotic marker in chronic kidney disease patients. We conducted a cross-sectional observational study on 54 hemodialysis patients. We recorded clinical and biological data and we measured sTWEAK serum levels by ELISA. We evaluated the arterial brachial function by measurement of flow-mediated and nitroglycerin-mediated dilation, using B mode ultrasound. The determinants of flow-mediated dilation were: Kt/V (r=0.47, p<0.001), LDL-cholesterol (r=0.29, p=0.04), and total cholesterol (r=0.31, p=0.02). Flow-mediated dilation correlated with nitroglycerin-mediated dilation (r=0.70, p<0.001). In multivariate analysis kt/V was the only significant predictor for flow-mediated dilation (p=0.04). Nitroglycerin-mediated dilation correlates with sTWEAK (r=-0.30, p=0.03), systolic blood pressure (r=-0.28, p=0.04) and pulse pressure (r=-0.31, p=0.02). In multivariate analysis sTWEAK was the only significant predictor for nitroglycerin-mediated dilation (p=0.04). The main determinant of nitroglycerin-mediated dilation was sTWEAK. In addition, decreased nitroglycerin-mediated dilation was associated with higher systolic blood pressure and pulse pressure. The main determinant of FMD was Kt/V. Increased flow-mediated dilation was associated with better dialysis efficiency and high total cholesterol and LDL-cholesterol.

Hygroscopic dilators vs balloon catheter ripening of the cervix for induction of labor in nulliparous women at term: Retrospective study

PubMed Central

Shindo, Ryosuke; Yonemoto, Naohiro; Yamamoto, Yuriko; Kasai, Junko; Kasai, Michi; Miyagi, Etsuko

2017-01-01

Objective To compare the efficacy and safety of hygroscopic dilators and balloon catheters for ripening of the cervix in induction of labor. Study design This retrospective, observational study used data from the Successive Pregnancy Birth Registry System of the Japan Society of Obstetrics and Gynecology from 2012 to 2014. Nulliparous women in whom labor was induced by mechanical methods of cervical ripening at term were enrolled. The eligible women were divided into dilator, balloon <40 mL, balloon ≧40 mL, and overlapping groups. Results The groups included 4645, 4100, 6615, and 1992 women, respectively. In the overlapping group, which included the women in whom delivery was most difficult, the vaginal delivery rate was lower and the intrauterine infection and neonatal mortality rates were higher than those in the dilator group. No difference in the vaginal delivery rate was observed among the dilator, balloon <40 mL, and balloon ≧40 mL groups (74.6%, 72.3%, and 73.8%, respectively; p>0.05). The vaginal instrumental delivery rate was higher in the two-balloon groups than in the dilator group. The volume of intrapartum hemorrhage was lowest in the dilator group. No significant difference in the frequencies of uterine rupture and intrauterine infection were observed among the dilator and two-balloon groups. With regard to neonatal outcomes, the frequency of a low Apgar score was statistically significantly lower in the dilator group than in the two-balloon groups. Moreover, the frequency of neonatal death tended to be lower in the dilator group than in the two-balloon groups. Conclusion With regard to cervical ripening for labor induction in nulliparous women at term, the vaginal delivery rate on using a dilator and on using a balloon seems to be equivalent. Concerning maternal complications and neonatal outcomes, cervical ripening with hygroscopic dilators in labor induction might be safer. PMID:29272277

Recovery of normal esophageal function in a kitten with diffuse megaesophagus and an occult lower esophageal stricture.

PubMed

Schneider, Jaycie; Ames, Marisa; DiCicco, Michael; Savage, Mason; Atkins, Clarke; Wood, Michael; Gookin, Jody L

2015-06-01

An 8-week-old male domestic shorthair was presented to the Internal Medicine Service at North Carolina State University for regurgitation. Radiographic diagnosis of generalized esophageal dilation and failure of esophageal peristalsis were compatible with diagnosis of congenital megaesophagus. Endoscopic examination of the esophagus revealed a fibrous stricture just orad to the lower esophageal sphincter. Conservative management to increase the body condition and size of the kitten consisted of feeding through a gastrostomy tube, during which time the esophagus regained normal peristaltic function, the stricture orifice widened in size and successful balloon dilatation of the stricture was performed. Esophageal endoscopy should be considered to rule out a stricture near the lower esophageal sphincter in kittens with radiographic findings suggestive of congenital megaesophagus. Management of such kittens by means of gastrostomy tube feeding may be associated with a return of normal esophageal motility and widening of the esophageal stricture, and facilitate subsequent success of interventional dilation of the esophageal stricture. © ISFM and AAFP 2014.

The sliding rail system (monorail): description of a new technique for intravascular instrumentation and its application to coronary angioplasty.

PubMed

Bonzel, T; Wollschläger, H; Kasper, W; Meinertz, T; Just, H

1987-01-01

The sliding rail technique is a new technique for intravascular instrumentation, especially coronary stenosis dilatation. The so-called monorail balloon catheter is the first device which can be used according to this technique. The monorail catheter has a single lumen shaft and only a short central tube within the distal balloon part. With the guidewire inserted into the tube, the balloon can be advanced or retracted on the guidewire as on a sliding rail. The most relevant improvements for coronary dilatation are steerability, contrast flow and rapid and easy exchangeability of balloon catheters and other intracoronary devices. These characteristics are felt to result in a more simple and time- and fluoroscopy-saving dilatation procedure. A special transfusion catheter may also improve procedural safety. The first clinical results in 69 patients with a success rate of 96%, an emergency bypass rate of two patients (one infarction) and a stenosis improvement of 58% confirm the theoretically conceived advantages.

Treatment of dilated cardiomyopathy with carvedilol in children.

PubMed

Erdoğan, Ilkay; Ozer, Sema; Karagöz, Tevfik; Celiker, Alpay; Ozkutlu, Süheyla; Alehan, Dursun

2009-01-01

We performed a study to examine the clinical use of carvedilol, its dosage and its effects on systolic functions in children. Twenty-one patients with dilated cardiomyopathy who were treated with carvedilol adjacent to standard heart failure therapy were enrolled in the study. Echocardiographic assessment was obtained before and during carvedilol therapy, and left ventricular fractional shortening and left ventricular ejection fraction were determined in order to estimate left ventricular function. At a follow-up of six months, left ventricular ejection fraction and fractional shortening significantly improved from 38 +/- 10% to 53 +/- 13% and from 19 +/- 6 % to 27 +/- 8%, respectively, following carvedilol treatment. The results of the present study indicate that carvedilol is well tolerated in children with dilated cardiomyopathy and there is a significant improvement in the clinical status and left ventricular ejection fraction in patients not responding to conventional therapy. Patient selection criteria, optimal timing of carvedilol therapy, its dosage and its long-term effects need to be investigated with multi-institutional trials and large numbers of patients.

Impaired activity of adherens junctions contributes to endothelial dilator dysfunction in ageing rat arteries.

PubMed

Chang, Fumin; Flavahan, Sheila; Flavahan, Nicholas A

2017-08-01

Ageing-induced endothelial dysfunction contributes to organ dysfunction and progression of cardiovascular disease. VE-cadherin clustering at adherens junctions promotes protective endothelial functions, including endothelium-dependent dilatation. Ageing increased internalization and degradation of VE-cadherin, resulting in impaired activity of adherens junctions. Inhibition of VE-cadherin clustering at adherens junctions (function-blocking antibody; FBA) reduced endothelial dilatation in young arteries but did not affect the already impaired dilatation in old arteries. After junctional disruption with the FBA, dilatation was similar in young and old arteries. Src tyrosine kinase activity and tyrosine phosphorylation of VE-cadherin were increased in old arteries. Src inhibition increased VE-cadherin at adherens junctions and increased endothelial dilatation in old, but not young, arteries. Src inhibition did not increase dilatation in old arteries treated with the VE-cadherin FBA. Ageing impairs the activity of adherens junctions, which contributes to endothelial dilator dysfunction. Restoring the activity of adherens junctions could be of therapeutic benefit in vascular ageing. Endothelial dilator dysfunction contributes to pathological vascular ageing. Experiments assessed whether altered activity of endothelial adherens junctions (AJs) might contribute to this dysfunction. Aortas and tail arteries were isolated from young (3-4 months) and old (22-24 months) F344 rats. VE-cadherin immunofluorescent staining at endothelial AJs and AJ width were reduced in old compared to young arteries. A 140 kDa VE-cadherin species was present on the cell surface and in TTX-insoluble fractions, consistent with junctional localization. Levels of the 140 kDa VE-cadherin were decreased, whereas levels of a TTX-soluble 115 kDa VE-cadherin species were increased in old compared to young arteries. Acetylcholine caused endothelium-dependent dilatation that was decreased in old compared to young arteries. Disruption of VE-cadherin clustering at AJs (function-blocking antibody, FBA) inhibited dilatation to acetylcholine in young, but not old, arteries. After the FBA, there was no longer any difference in dilatation between old and young arteries. Src activity and tyrosine phosphorylation of VE-cadherin were increased in old compared to young arteries. In old arteries, Src inhibition (saracatinib) increased: (i) 140 kDa VE-cadherin in the TTX-insoluble fraction, (ii) VE-cadherin intensity at AJs, (iii) AJ width, and (iv) acetylcholine dilatation. In old arteries treated with the FBA, saracatinib no longer increased acetylcholine dilatation. Saracatinib did not affect dilatation in young arteries. Therefore, ageing impairs AJ activity, which appears to reflect Src-induced phosphorylation, internalization and degradation of VE-cadherin. Moreover, impaired AJ activity can account for the endothelial dilator dysfunction in old arteries. Restoring endothelial AJ activity may be a novel therapeutic approach to vascular ageing. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Massage Therapy and Labor Outcomes: a Randomized Controlled Trial

PubMed Central

Janssen, Patricia; Shroff, Farah; Jaspar, Paula

2012-01-01

Introduction Massage is a time-honored method by which women have received comfort throughout the millennia, yet it has not been rigorously evaluated in the modern day delivery suite. No study to date that we are aware of has evaluated the effect of massage therapy by a regulated massage therapist on labor pain. The purpose of this study was to evaluate the effectiveness of massage therapy provided by registered massage therapists in managing pain among women in active labor. Methods BC Women’s Hospital, Vancouver, BC. Research Design: a randomized controlled trial. Participants: 77 healthy nulliparous women presenting in spontaneous labor. Intervention: Swedish massage administered for up to five hours by a registered massage therapist during labor vs. standard care. Main outcome measures include: cervical dilation at the time of administration of epidural, compared using estimated marginal means in an analysis of covariance. We also compared perception of pain at three time periods during labor according to cervical dilation at 3–4 cm, 5–7 cm, and 8–10 cm using the McGill Present Pain Intensity Scale. Results The mean cervical dilation at the time of epidural insertion after adjustment for station of the presenting part, cervical dilation, and status of membranes on admission to hospital was 5.9 cm (95% CI 5.2–6.7) compared to 4.9 in the control group (95% CI 4.2–5.8). Scores on the McGill Pain Scale were consistently lower in the massage therapy group (13.3 vs. 16.9 at 3–4 cm, 13.3 vs. 15.8 at 5–6 cm, and 19.4 vs. 28.3 at 7–8 cm), although these differences were not statistically significant. Conclusions Our findings from this pilot study suggest that massage therapy by a registered massage therapist has the potential to be an effective means of pain management that may be associated with delayed use of epidural analgesia. It may therefore have the potential to reduce exposure to epidural analgesia during labor and decrease rates of associated sequelae. PMID:23429706

Relativistic timescale analysis suggests lunar theory revision

NASA Astrophysics Data System (ADS)

Deines, Steven D.; Williams, Carol A.

1995-05-01

The SI second of the atomic clock was calibrated to match the Ephemeris Time (ET) second in a mutual four year effort between the National Physical Laboratory (NPL) and the United States Naval Observatory (USNO). The ephemeris time is 'clocked' by observing the elapsed time it takes the Moon to cross two positions (usually occultation of stars relative to a position on Earth) and dividing that time span into the predicted seconds according to the lunar equations of motion. The last revision of the equations of motion was the Improved Lunar Ephemeris (ILE), which was based on E. W. Brown's lunar theory. Brown classically derived the lunar equations from a purely Newtonian gravity with no relativistic compensations. However, ET is very theory dependent and is affected by relativity, which was not included in the ILE. To investigate the relativistic effects, a new, noninertial metric for a gravitated, translationally accelerated and rotating reference frame has three sets of contributions, namely (1) Earth's velocity, (2) the static solar gravity field and (3) the centripetal acceleration from Earth's orbit. This last term can be characterized as a pseudogravitational acceleration. This metric predicts a time dilation calculated to be -0.787481 seconds in one year. The effect of this dilation would make the ET timescale run slower than had been originally determined. Interestingly, this value is within 2 percent of the average leap second insertion rate, which is the result of the divergence between International Atomic Time (TAI) and Earth's rotational time called Universal Time (UT or UTI). Because the predictions themselves are significant, regardless of the comparison to TAI and UT, the authors will be rederiving the lunar ephemeris model in the manner of Brown with the relativistic time dilation effects from the new metric to determine a revised, relativistic ephemeris timescale that could be used to determine UT free of leap second adjustments.

Relativistic timescale analysis suggests lunar theory revision

NASA Technical Reports Server (NTRS)

Deines, Steven D.; Williams, Carol A.

1995-01-01

The SI second of the atomic clock was calibrated to match the Ephemeris Time (ET) second in a mutual four year effort between the National Physical Laboratory (NPL) and the United States Naval Observatory (USNO). The ephemeris time is 'clocked' by observing the elapsed time it takes the Moon to cross two positions (usually occultation of stars relative to a position on Earth) and dividing that time span into the predicted seconds according to the lunar equations of motion. The last revision of the equations of motion was the Improved Lunar Ephemeris (ILE), which was based on E. W. Brown's lunar theory. Brown classically derived the lunar equations from a purely Newtonian gravity with no relativistic compensations. However, ET is very theory dependent and is affected by relativity, which was not included in the ILE. To investigate the relativistic effects, a new, noninertial metric for a gravitated, translationally accelerated and rotating reference frame has three sets of contributions, namely (1) Earth's velocity, (2) the static solar gravity field and (3) the centripetal acceleration from Earth's orbit. This last term can be characterized as a pseudogravitational acceleration. This metric predicts a time dilation calculated to be -0.787481 seconds in one year. The effect of this dilation would make the ET timescale run slower than had been originally determined. Interestingly, this value is within 2 percent of the average leap second insertion rate, which is the result of the divergence between International Atomic Time (TAI) and Earth's rotational time called Universal Time (UT or UTI). Because the predictions themselves are significant, regardless of the comparison to TAI and UT, the authors will be rederiving the lunar ephemeris model in the manner of Brown with the relativistic time dilation effects from the new metric to determine a revised, relativistic ephemeris timescale that could be used to determine UT free of leap second adjustments.

Clinical profile and management options of children with congenital esophageal stenosis: A single center experience.

PubMed

Kurian, Jujju Jacob; Jehangir, Susan; Varghese, Isaac Tharu; Thomas, Reju Joseph; Mathai, John; Karl, Sampath

2016-01-01

The aim of the study is to review 7 patients with congenital esophageal stenosis treated in our institution from a diagnostic and therapeutic point of view. This is a retrospective cohort study of 7 patients treated in Christian Medical College, Vellore from 2008 to 2014. The data were analyzed with regards to age at onset of symptoms, investigative findings, age at definitive treatment, pathology, modalities of treatment, and outcomes. Symptoms started within the 1(st) year of life in all children with a median age of 4 months. The time of delay in diagnosis ranged from 8 months to 81 months with a mean period of 37 months. About 6 patients had a lower esophageal stenosis and 1 patient had a mid-esophageal stenosis. About 4 of the 7 children underwent endoscopic balloon dilatation from elsewhere, with 2 of the above 4 undergoing a myotomy for a wrongly diagnosed achalasia. The number of dilatations ranged from 2 to 7 with a mean of 4 dilatations. Resection of the stenotic segment with end to end anastomosis was employed in 6 of the 7 patients, and a transverse colon interpositioning was done in 1 patient. An antireflux procedure was performed in one patient. Histopathological examination of the resected specimen revealed tracheobronchial remnant in 3 patients, fibromuscular thickening in 3 patients, and membranous web in 1 patient. Postoperatively, 2 of the 7 patients had asymptomatic gastroesophageal reflux and 1 patient had postoperative stricture requiring one session of endoscopic balloon dilatation. The mean follow-up period was 42 months (range 18-72 months). At the time of the last follow-up, all 7 patients were able to eat solid food, and none of the children were found to have symptoms suggestive of obstruction or gastroesophageal reflux. There was a statistically significant increase in the weight for age after the operation. Congenital esophageal stenosis is rare and often confused with other causes of esophageal obstruction. Although endoscopic balloon dilatation offers an effective temporary relief, we feel that definitive surgery is curative. Long-term results following definitive surgery have been good, especially with respect to symptoms and weight gain.

Bond length variation in Zn substituted NiO studied from extended X-ray absorption fine structure

NASA Astrophysics Data System (ADS)

Singh, S. D.; Poswal, A. K.; Kamal, C.; Rajput, Parasmani; Chakrabarti, Aparna; Jha, S. N.; Ganguli, Tapas

2017-06-01

Bond length behavior for Zn substituted NiO is determined through extended x-ray absorption fine structure (EXAFS) measurements performed at ambient conditions. We report bond length value of 2.11±0.01 Å for Zn-O of rock salt (RS) symmetry, when Zn is doped in RS NiO. Bond length for Zn substituted NiO RS ternary solid solutions shows relaxed behavior for Zn-O bond, while it shows un-relaxed behavior for Ni-O bond. These observations are further supported by first-principles calculations. It is also inferred that Zn sublattice remains nearly unchanged with increase in lattice parameter. On the other hand, Ni sublattice dilates for Zn compositions up to 20% to accommodate increase in the lattice parameter. However, for Zn compositions more than 20%, it does not further dilate. It has been attributed to the large disorder that is incorporated in the system at and beyond 20% of Zn incorporation in the cubic RS lattice of ternary solid solutions. For these large percentages of Zn incorporation, the Ni and the Zn atoms re-arrange themselves microscopically about the same nominal bond length rather than systematically increase in magnitude to minimize the energy of the system. This results in an increase in the Debye-Waller factor with increase in the Zn concentration rather than a systematic increase in the bond lengths.

Discrimination of bilateral finger photoplethysmogram responses to reactive hyperemia in diabetic and healthy subjects using a differential vascular model framework.

PubMed

Keikhosravi, Adib; Aghajani, Haleh; Zahedi, Edmond

2013-05-01

Endothelial dysfunction assessment has received considerable attention due to its potential in early screening of cardiovascular diseases. Since the seminal work by Celermajer in flow-mediated dilation (FMD) based on B-mode ultrasound measurement of the brachial artery dilation following limb ischemia, many attempts have been made toward applying this method to clinical, non-invasive endothelial dysfunction assessment. One major obstacle toward achieving this objective has been the relative high cost of the required setup and skilled manpower. Such limitations have prompted the investigation of other non-invasively accessible signals such as the photoplethysmogram (PPG) in relation to FMD. It is in the above context that this paper proposes to use a modified version of an existing differential model of the human upper vasculature in order to discriminate between healthy and diabetic subjects. PPG from 46 subjects (23 healthy and 23 diabetic) were utilized to identify the model parameters. Once the model parameters were identified, singular value decomposition was applied to reduce the number of features and increase the separability. Finally, a naive Bayes classifier resulted in an overall accuracy of 93.5% (Spec. 87.0% and Sens. 100%). Taking into account subjects' gender further improved the overall accuracy. It is thought that the application of the proposed method to endothelial dysfunction assessment may positively impact the deployment of FMD in clinical settings.

High-Resolution Manometry Evaluation of the Pharynx and Upper Esophageal Sphincter Motility in Patients with Achalasia.

PubMed

Menezes, Mariano A; Herbella, Fernando A M; Patti, Marco G

2015-10-01

The motility of the pharynx and upper esophageal sphincter (UES) is still poorly understood. It is also unclear if the motility of this area may be compromised in patients with achalasia. This study aims to evaluate the motility of the pharynx, UES, and proximal esophagus in patients with esophageal achalasia. Sixty patients with achalasia underwent high-resolution manometry (HRM) (52 % females, mean age 54 years). Esophageal dilatation was classified according to the radiologic diameter in Type I (<4 cm): 6 %; Type II (4-7 cm): 36 %; Type III (7-10 cm): 34 %; and Type IV (>10 cm): 24 %. HRM classified 43 % of the patients as Chicago Type I and 57 % as Type II. Manometric parameters were compared to normal values obtained from a previous study in volunteers. The motility of the velopharynx showed short, premature, and hypertonic contraction. The epiglottis also showed hypertonic contraction. The UES had increased residual pressure. Chicago classification Type II patients had higher UES residual pressure (p = 0.03). The degree of esophageal dilatation did not correlate with manometric parameters. Achalasia may affect the motility of the pharyngo-upper esophageal area. The changes observed may represent functional alterations to prevent aspiration, especially in patients with Chicago classification Type II achalasia.

Circadian and Fatigue Effects on the Dynamics of the Pupillary Light Reflex

NASA Technical Reports Server (NTRS)

Tyson, Terence L.; Flynn-Evans, Erin E.; Stone, Leland S.

2017-01-01

The pupillary light reflex (PLR) is known to be driven by the photo-entrainment of intrinsically-photosensitive retinal ganglion cells. These ganglion cells are known to have retino-hypothalamic projections to the suprachiasmatic nuclei (SCN), which regulates circadian rhythms, and bilateral retinal projections to the pretectal area, which mediates the PLR (Dacey et al., 2005; Hattar et al., 2002, 2006). The magnitude of the PLR has previously been shown to show circadian variation (Mnch et al., 2012). In this study, we used a constant routine protocol (Mills et al., 1978) to examine circadian and fatigue effects on the dynamics of the PLR. We characterized the PLR (pupil size as a function of time) in response to a square-wave change in the luminance of a white display background, at ten different times over a single circadian cycle. Twelve subjects participated in three daytime baseline runs followed by 7 nighttime runs each separated by an hour (17 23 hours after awakening). The constriction and dilation phases of the PLR waveform were fit separately with a single exponential model (Longtin Milton, 1988; Milton Longtin, 1990) with time constants estimated using a least-squares method. The dilation time constant exhibited a distinct sinusoidal modulation across the circadian cycle and, after 23 hours of wakefulness, decreased on average by 82 ms (paired t-test, p 0.05) relative to baseline (mean: 543 ms). The constriction time constant however, did not show an overall decrease with increased wakefulness. We conclude that the dynamics of the PLR show circadian variation and that, in addition, the briskness of the dilation response to a step-decrease in luminance shows a homeostatic enhancement with increased wakefulness.

A comparison of two methods of endoscopic dilation of acute subglottic stenosis using a ferret model.

PubMed

Tubbs, Kyle J; Silva, Rodrigo C; Ramirez, Harvey E; Castleman, William L; Collins, William O

2013-01-01

Balloon dilation is accepted as a first line treatment of acute subglottic stenosis, but its effects on the subglottic tissue remain largely unknown. We aimed to develop an animal model of acute subglottic stenosis using endoscopic techniques. Once developed, this model was used to compare the immediate effects of balloon dilation and endotracheal tube dilation on subglottic tissue. Prospective randomized animal study. Acute subglottic injury was induced in 10 ferrets by endoscopic cauterization with silver nitrate. After 48-72 hours of observation, eight animals were randomized to undergo subglottic dilation with either a 5-mm balloon or endotracheal tubes of increasing diameter. These eight ferrets were euthanized within 10 minutes after dilation. The other two ferrets served as controls and were euthanized following observation only. The larynx from each ferret was harvested, and the subglottis was examined histologically by a pathologist blinded to the treatment arms. Acute subglottic stenosis was induced in all 10 ferrets using the endoscopic technique. Both balloon and endotracheal tube dilation resulted in comparable improvement in the subglottic airway diameter. A decreased thickness of submucosa/lamina propria was seen in the balloon dilation group. Acute subglottic stenosis can be reliably induced in ferrets using endoscopic techniques. Multiple dilation methods can be used to relieve acute obstruction. Balloon dilators seem to improve airway patency, in part, by decreasing the thickness of the submucosa and lamina propria. Further research is needed to determine how this impacts later stages of wound healing and final outcomes. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Pupil dilation signals uncertainty and surprise in a learning gambling task.

PubMed

Lavín, Claudio; San Martín, René; Rosales Jubal, Eduardo

2013-01-01

Pupil dilation under constant illumination is a physiological marker where modulation is related to several cognitive functions involved in daily decision making. There is evidence for a role of pupil dilation change during decision-making tasks associated with uncertainty, reward-prediction errors and surprise. However, while some work suggests that pupil dilation is mainly modulated by reward predictions, others point out that this marker is related to uncertainty signaling and surprise. Supporting the latter hypothesis, the neural substrate of this marker is related to noradrenaline (NA) activity which has been also related to uncertainty signaling. In this work we aimed to test whether pupil dilation is a marker for uncertainty and surprise in a learning task. We recorded pupil dilation responses in 10 participants performing the Iowa Gambling Task (IGT), a decision-making task that requires learning and constant monitoring of outcomes' feedback, which are important variables within the traditional study of human decision making. Results showed that pupil dilation changes were modulated by learned uncertainty and surprise regardless of feedback magnitudes. Interestingly, greater pupil dilation changes were found during positive feedback (PF) presentation when there was lower uncertainty about a future negative feedback (NF); and by surprise during NF presentation. These results support the hypothesis that pupil dilation is a marker of learned uncertainty, and may be used as a marker of NA activity facing unfamiliar situations in humans.

Pupil dilation signals uncertainty and surprise in a learning gambling task

PubMed Central

Lavín, Claudio; San Martín, René; Rosales Jubal, Eduardo

2014-01-01

Pupil dilation under constant illumination is a physiological marker where modulation is related to several cognitive functions involved in daily decision making. There is evidence for a role of pupil dilation change during decision-making tasks associated with uncertainty, reward-prediction errors and surprise. However, while some work suggests that pupil dilation is mainly modulated by reward predictions, others point out that this marker is related to uncertainty signaling and surprise. Supporting the latter hypothesis, the neural substrate of this marker is related to noradrenaline (NA) activity which has been also related to uncertainty signaling. In this work we aimed to test whether pupil dilation is a marker for uncertainty and surprise in a learning task. We recorded pupil dilation responses in 10 participants performing the Iowa Gambling Task (IGT), a decision-making task that requires learning and constant monitoring of outcomes’ feedback, which are important variables within the traditional study of human decision making. Results showed that pupil dilation changes were modulated by learned uncertainty and surprise regardless of feedback magnitudes. Interestingly, greater pupil dilation changes were found during positive feedback (PF) presentation when there was lower uncertainty about a future negative feedback (NF); and by surprise during NF presentation. These results support the hypothesis that pupil dilation is a marker of learned uncertainty, and may be used as a marker of NA activity facing unfamiliar situations in humans. PMID:24427126

Mitomycin C and the endoscopic treatment of laryngotracheal stenosis: are two applications better than one?

PubMed

Smith, Marshall E; Elstad, Mark

2009-02-01

Endoscopic treatment of laryngotracheal stenosis by airway dilation, despite short-term improvement, is often associated with long-term relapse. Mitomycin-C (MMC) inhibits fibroblast proliferation and synthesis of extracellular matrix proteins, and thereby modulates wound healing and scarring. MMC application at the time of endoscopic dilation and laser surgery has been suggested to improve outcomes, but this has not been studied in a rigorous manner. This study examines the hypothesis that two topical applications of MMC given 3-6 weeks apart will result in decreased scarring/restenosis of the airway, when compared to a single topical application. A randomized, prospective, double-blind, placebo-controlled clinical trial. Twenty-six patients with laryngotracheal stenosis due to idiopathic subglottic stenosis, postintubation stenosis, or Wegener's granulomatosis entered a protocol to receive three endoscopic CO(2) laser and dilation procedures over a 3-month interval. At the first procedure, after radial CO(2) laser incision and airway dilation, all patients received topical application of MMC (0.5 mg/mL) to the airway lesion. One month later, a second endoscopic incision and dilation was performed and the patients were randomized to either a second application of mitomycin-C or to application of saline placebo. A third dilation procedure was performed 2 months later, without MMC application. Patients were followed for up to 5 years for relapse of airway stenosis with clinical symptoms sufficient to require a subsequent procedure. The relapse rates at 1, 3, and 5 years were 7%, 36%, and 69% for patients treated with two applications of MMC compared to 33%, 58%, and 70% for patients treated with one application of MMC. The median interval to relapse was 3.8 years in the two-application group, compared with 2.4 years in the one-application group. This prospective randomized double-blind placebo-controlled trial suggests that, in the endoscopic management of laryngotracheal stenosis, two applications of MMC given 3-4 weeks apart after airway radial incision and dilation reduces the restenosis rate for 2 to 3 years after treatment when compared to a single application. However, restenosis and delayed symptom recurrence continues so that at 5 years the relapse rates are the same. Thus, MMC may postpone, but does not prevent, the recurrence of symptomatic stenosis in the majority of patients.

Concomitant replacement of the dilated ascending aorta during aortic valve replacement; does it increase the perioperative morbidity and mortality risks?

PubMed

Lim, Ju Y; Jung, Sung H; Kim, Joon B; Kim, Dong K; Chung, Cheol H; Song, Hyun; Lee, Jae W; Choo, Suk J

2013-05-01

Concerns of increased surgical risks with ascending aortic replacement have led surgeons to manage post-stenotic aortic dilatation more conservatively during aortic valve replacement (AVR). The present study aimed to assess the prognostic implications and surgical risks of replacing the dilated aorta during AVR. Between January 1999 and March 2010, 134 patients who received surgery for aortic stenosis and post-stenotic dilatation (aorta size ≥40 mm) were included in the present study. AVR was performed in 92 patients (AVR group) while aortic valve and ascending aorta replacement (AVR + aorta group) were performed in 42 patients. Overall survival was compared between the two groups using Cox proportional hazard model after adjustment with inverse-probability-of-treatment weighting. The mean follow-up duration was 3.5 ± 3 years. There were no significant differences in the operative mortality and morbidity between the two groups. The late cardiac deaths were also not significantly different between the two groups (p = 1.00). In the AVR group, the ascending aortic expansion rate which was 0.18 mm/year over a mean follow-up duration of 2.3 ± 2.2 years by echocardiography showed a positive correlation with time (r = 0.3, p = 0.08). A relatively greater aortic expansion rate was identified as a risk factor for late mortality (p = 0.015, HR 1.08 (CI: 1.02 to 1.15). Concomitant replacement of the dilated ascending aorta during AVR did not increase the immediate postoperative morbidity or mortality risks and tended to exert a long-term beneficial effect on the risk of late mortality. © 2013 Wiley Periodicals, Inc.

Cardiovascular Magnetic Resonance Findings Late After the Arterial Switch Operation.

PubMed

Shepard, Charles W; Germanakis, Ioannis; White, Matthew T; Powell, Andrew J; Co-Vu, Jennifer; Geva, Tal

2016-09-01

Despite its robust diagnostic capabilities in adolescents and adult patients after the arterial switch operation, little information is available on the cardiovascular magnetic resonance findings in this population. The cardiovascular magnetic resonance findings of 220 consecutive patients evaluated in our center were retrospectively reviewed (median age at cardiovascular magnetic resonance, 15.4 years; 66.8% male sex). Compared with published normal values, left and right ventricular end-diastolic volume z scores were mildly enlarged (0.48±1.76 and 0.33±1.5; P=0.0003 and 0.0038, respectively), with 26% of patients having left ventricular dilatation and 20% having right ventricular dilatation. Left ventricular dysfunction was present in 21.5% of patients (mild in most), and only 5.1% of patients had mild right ventricular dysfunction. Myocardial scar was found in 1.8% of patients. Dilatation of the neoaortic root was common (76%), and root z score increased at an average rate of 0.03 points per year. By multivariable analysis, neoaortic root dilatation was associated with worse neoaortic valve regurgitation (OR, 5.29; P=0.0016). The diameters of the thoracic aorta distal to the root were near-normal in most patients, whereas the neomain pulmonary artery was typically oval shaped with decreased anteroposterior and normal lateral diameters. Although the majority of arterial switch operation patients have normal ventricular size and function and myocardial scar is rare, an important minority exhibits ventricular enlargement or dysfunction. Neoaortic root dilatation, which is present in most patients and progresses over time, is strongly associated with significant neoaortic valve regurgitation. The findings of this study provide reference values against which arterial switch operation patients can be compared with their peers. © 2016 American Heart Association, Inc.

Treatments for pediatric achalasia: Heller myotomy or pneumatic dilatation?

PubMed

Jung, C; Michaud, L; Mougenot, J-F; Lamblin, M-D; Philippe-Chomette, P; Cargill, G; Bonnevalle, M; Boige, N; Bellaïche, M; Viala, J; Hugot, J-P; Gottrand, F; Cezard, J-P

2010-03-01

The treatment of achalasia consists of reducing distal esophageal obstruction by either Heller myotomy surgery or endoscopic pneumatic dilatation. The aim of the present study was to evaluate the short- and middle-term results of these procedures in children. For technical reasons, children under six years old (n=8) were treated by surgery only, whereas patients over six years old (n=14) were treated by either Heller myotomy or pneumatic dilatation. Of the children aged under six years, 75% were symptom-free at six months and 83% at 24 months of follow-up. Of the patients aged over six years, complete remission was achieved by Heller myotomy in 44.5% vs. 55.5% by pneumatic dilatation after six months, and in 40% vs. 65%, respectively, after 24 months. Both pneumatic dilatation and Heller myotomy showed significant rates of failure. These results suggest that pneumatic dilatation may be considered a primary treatment in children over six years old. Also, where necessary, Heller myotomy and pneumatic dilatation may be used as complementary treatments.

Superluminality in dilatationally invariant generalized Galileon theories

NASA Astrophysics Data System (ADS)

Kolevatov, R. S.

2015-12-01

We consider small perturbations about homogeneous backgrounds in dilatationally invariant Galileon models. The issues we address are stability (absence of ghosts and gradient instabilities) and superluminality. We show that in the Minkowski background, it is possible to construct the Lagrangian in such a way that any homogeneous Galileon background solution is stable and small perturbations about it are subluminal. On the other hand, in the case of Friedmann-Lemaitre-Robertson-Walker (FLRW) backgrounds, for any Lagrangian functions there exist homogeneous background solutions to the Galileon equation of motion and time dependence of the scale factor, such that the stability conditions are satisfied, but the Galileon perturbations propagate with superluminal speed.

Perception while watching movies: Effects of physical screen size and scene type.

PubMed

Troscianko, Tom; Meese, Timothy S; Hinde, Stephen

2012-01-01

Over the last decade, television screens and display monitors have increased in size considerably, but has this improved our televisual experience? Our working hypothesis was that the audiences adopt a general strategy that "bigger is better." However, as our visual perceptions do not tap directly into basic retinal image properties such as retinal image size (C. A. Burbeck, 1987), we wondered whether object size itself might be an important factor. To test this, we needed a task that would tap into the subjective experiences of participants watching a movie on different-sized displays with the same retinal subtense. Our participants used a line bisection task to self-report their level of "presence" (i.e., their involvement with the movie) at several target locations that were probed in a 45-min section of the movie "The Good, The Bad, and The Ugly." Measures of pupil dilation and reaction time to the probes were also obtained. In Experiment 1, we found that subjective ratings of presence increased with physical screen size, supporting our hypothesis. Face scenes also produced higher presence scores than landscape scenes for both screen sizes. In Experiment 2, reaction time and pupil dilation results showed the same trends as the presence ratings and pupil dilation correlated with presence ratings, providing some validation of the method. Overall, the results suggest that real-time measures of subjective presence might be a valuable tool for measuring audience experience for different types of (i) display and (ii) audiovisual material.

Spectral dilation of L(B,H)-valued measures and its application to stationary dilation for Banach space valued processes

NASA Technical Reports Server (NTRS)

Miamee, A. G.

1988-01-01

Let B be a Banach space and H and K two Hilbert spaces. The spectral dilation of L(B,H)-valued measures is studied and it is shown that the recent results of Makagon and Salehi (1986) and Rosenberg (1982) on the dilation of L(K,H)-valued measures can be extended to hold for the general Banach space setting of L(B,H)-valued measures. These L(B,H)-valued measures are closely connected to the Banach space valued processes. This connection is recalled and as application of spectral dilation of L(B,H)-valued measures the well known stationary dilation results for scalar valued processes is extended to the case of Banach space valued processes.

Serum proteome profiling in canine idiopathic dilated cardiomyopathy using TMT-based quantitative proteomics approach.

PubMed

Bilić, Petra; Guillemin, Nicolas; Kovačević, Alan; Beer Ljubić, Blanka; Jović, Ines; Galan, Asier; Eckersall, Peter David; Burchmore, Richard; Mrljak, Vladimir

2018-05-15

Idiopathic dilated cardiomyopathy (iDCM) is a primary myocardial disorder with an unknown aetiology, characterized by reduced contractility and ventricular dilation of the left or both ventricles. Naturally occurring canine iDCM was used herein to identify serum proteomic signature of the disease compared to the healthy state, providing an insight into underlying mechanisms and revealing proteins with biomarker potential. To achieve this, we used high-throughput label-based quantitative LC-MS/MS proteomics approach and bioinformatics analysis of the in silico inferred interactome protein network created from the initial list of differential proteins. To complement the proteomic analysis, serum biochemical parameters and levels of know biomarkers of cardiac function were measured. Several proteins with biomarker potential were identified, such as inter-alpha-trypsin inhibitor heavy chain H4, microfibril-associated glycoprotein 4 and apolipoprotein A-IV, which were validated using an independent method (Western blotting) and showed high specificity and sensitivity according to the receiver operating characteristic curve analysis. Bioinformatics analysis revealed involvement of different pathways in iDCM, such as complement cascade activation, lipoprotein particles dynamics, elastic fibre formation, GPCR signalling and respiratory electron transport chain. Idiopathic dilated cardiomyopathy is a severe primary myocardial disease of unknown cause, affecting both humans and dogs. This study is a contribution to the canine heart disease research by means of proteomic and bioinformatic state of the art analyses, following similar approach in human iDCM research. Importantly, we used serum as non-invasive and easily accessible biological source of information and contributed to the scarce data on biofluid proteome research on this topic. Bioinformatics analysis revealed biological pathways modulated in canine iDCM with potential of further targeted research. Also, several proteins with biomarker potential have been identified and successfully validated. Copyright © 2018 Elsevier B.V. All rights reserved.

Spectral element modelling of seismic wave propagation in visco-elastoplastic media including excess-pore pressure development

NASA Astrophysics Data System (ADS)

Oral, Elif; Gélis, Céline; Bonilla, Luis Fabián; Delavaud, Elise

2017-12-01

Numerical modelling of seismic wave propagation, considering soil nonlinearity, has become a major topic in seismic hazard studies when strong shaking is involved under particular soil conditions. Indeed, when strong ground motion propagates in saturated soils, pore pressure is another important parameter to take into account when successive phases of contractive and dilatant soil behaviour are expected. Here, we model 1-D seismic wave propagation in linear and nonlinear media using the spectral element numerical method. The study uses a three-component (3C) nonlinear rheology and includes pore-pressure excess. The 1-D-3C model is used to study the 1987 Superstition Hills earthquake (ML 6.6), which was recorded at the Wildlife Refuge Liquefaction Array, USA. The data of this event present strong soil nonlinearity involving pore-pressure effects. The ground motion is numerically modelled for different assumptions on soil rheology and input motion (1C versus 3C), using the recorded borehole signals as input motion. The computed acceleration-time histories show low-frequency amplification and strong high-frequency damping due to the development of pore pressure in one of the soil layers. Furthermore, the soil is found to be more nonlinear and more dilatant under triaxial loading compared to the classical 1C analysis, and significant differences in surface displacements are observed between the 1C and 3C approaches. This study contributes to identify and understand the dominant phenomena occurring in superficial layers, depending on local soil properties and input motions, conditions relevant for site-specific studies.

Dosimetric Factors Associated With Long-Term Dysphagia After Definitive Radiotherapy for Squamous Cell Carcinoma of the Head and Neck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caudell, Jimmy J.; Schaner, Philip E.; Desmond, Renee A.

2010-02-01

Purpose: Intensification of radiotherapy and chemotherapy for head-and-neck cancer may lead to increased rates of dysphagia. Dosimetric predictors of objective findings of long-term dysphagia were sought. Methods and Materials: From an institutional database, 83 patients were identified who underwent definitive intensity-modulated radiotherapy for squamous cell carcinoma of the head and neck, after exclusion of those who were treated for a second or recurrent head-and-neck primary lesion, had locoregional recurrence at any time, had less than 12 months of follow-up, or had postoperative radiotherapy. Dosimetric parameters were analyzed relative to three objective endpoints as a surrogate for severe long-term dysphagia: percutaneousmore » endoscopic gastrostomy (PEG) tube dependence at 12 months, aspiration on modified barium swallow, or pharyngoesophageal stricture requiring dilation. Results: Mean dose greater than 41 Gy and volume receiving 60 Gy (V{sub 60}) greater than 24% to the larynx were significantly associated with PEG tube dependence and aspiration. V{sub 60} greater than 12% to the inferior pharyngeal constrictor was also significantly associated with increased PEG tube dependence and aspiration. V{sub 65} greater than 33% to the superior pharyngeal constrictor or greater than 75% to the middle pharyngeal constrictor was associated with pharyngoesophageal stricture requiring dilation. Conclusions: Doses to the larynx and pharyngeal constrictors predicted long-term swallowing complications, even when controlled for other clinical factors. The addition of these structures to intensity-modulated radiotherapy optimization may reduce the incidence of dysphagia, although cautious clinical validation is necessary.« less

High-frequency ground motion amplification during the 2011 Tohoku earthquake explained by soil dilatancy

NASA Astrophysics Data System (ADS)

Roten, D.; Fäh, D.; Bonilla, L. F.

2013-05-01

Ground motions of the 2011 Tohoku earthquake recorded at Onahama port (Iwaki, Fukushima prefecture) rank among the highest accelerations ever observed, with the peak amplitude of the 3-D acceleration vector approaching 2g. The response of the site was distinctively non-linear, as indicated by the presence of horizontal acceleration spikes which have been linked to cyclic mobility during similar observations. Compared to records of weak ground motions, the response of the site during the Mw 9.1 earthquake was characterized by increased amplification at frequencies above 10 Hz and in peak ground acceleration. This behaviour contrasts with the more common non-linear response encountered at non-liquefiable sites, which results in deamplification at higher frequencies. We simulate propagation of SH waves through the dense sand deposit using a non-linear finite difference code that is capable of modelling the development of excess pore water pressure. Dynamic soil parameters are calibrated using a direct search method that minimizes the difference between observed and simulated acceleration envelopes and response spectra. The finite difference simulations yield surface acceleration time-series that are consistent with the observations in shape and amplitude, pointing towards soil dilatancy as a likely explanation for the high-frequency pulses recorded at Onahama port. The simulations also suggest that the occurrence of high-frequency spikes coincided with a rapid increase in pore water pressure in the upper part of the sand deposit between 145 and 170 s. This sudden increase is possibly linked to a burst of high-frequency energy from a large slip patch below the Iwaki region.

Ivabradine, a novel heart rate slower: is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?

PubMed

Rayan, Mona; Tawfik, Mazen; Alabd, Ali; Gamal, Amr

2011-08-01

To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy. We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF) <40% and heart rate >70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis. We found a significant reduction in the resting heart rate by a mean of 25.9 ± 9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001). There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both). One patient developed photopsia and decompensation was observed in another patient. Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.

An exploratory investigation of echocardiographic parameters and the effects of posture on cardiac structure and function in the Livingstone's fruit bat (Pteropus livingstonii).

PubMed

Drane, Aimee L; Shave, Robert; Routh, Andrew; Barbon, Alberto

2018-01-01

There is growing evidence that dilated cardiomyopathy may be a major cause of death in captive Livingstone's fruit bats (Pteropus livingstonii). Therefore, the primary aim of this prospective, exploratory study was to examine whether a systematic cardiac ultrasound protocol is feasible in this critically endangered species and to report basic measures of cardiac structure and function from a cohort of apparently healthy bats. A secondary aim was to test the effect posture (dorsal recumbency vs. roosting) has upon cardiac function in this species. Transthoracic echocardiograms, including 2D, Doppler, and tissue Doppler measures of cardiac structure and function were completed as part of routine health examinations for bats at a single center (n = 19). Bats were then grouped by age and disease status and the mean and range data reported for each group. In healthy adult bats, with the exception of a reduction in heart rate (P ≤ 0.05), right atrial systolic area (P ≤ 0.05), and right ventricular velocity during atrial contraction, there were no significant changes in cardiac structure or function in response to the roosting position. However, in the bats presenting with dilated cardiomyopathy the current data suggest that left ventricular ejection fraction is improved while roosting. Further work is required to confirm our initial findings, generate diagnostic reference intervals, and explore the causes of dilated cardiomyopathy in this species. © 2017 American College of Veterinary Radiology.

Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries

PubMed Central

Brownbill, Paul; Janáček, Jiří; Jirkovská, Marie; Kubínová, Lucie; Chernyavsky, Igor L.; Jensen, Oliver E.

2016-01-01

During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations. PMID:27788214

Dilated cardiomyopathy secondary to rickets-related hypocalcaemia: eight case reports and a review of the literature.

PubMed

Yilmaz, Osman; Olgun, Hasim; Ciftel, Murat; Kilic, Omer; Kartal, Ibrahim; Iskenderoglu, Nebahat Y; Laloglu, Fuat; Ceviz, Naci

2015-02-01

Dilated cardiomyopathy is usually idiopathic and may arise secondary to infections or metabolic or genetic causes. Another rare cause is hypocalcaemia. Owing to the fact that calcium plays an essential role in excitation and contraction of myocardial muscle, myocardial contractility may decline in patients with hypocalcaemia. Patients with symptoms of congestive heart failure and rickets-related hypocalcaemia were assessed clinically and by echocardiography in a paediatric cardiology clinic. Echocardiography was performed for all patients. Rickets was diagnosed according to the clinical, laboratory, and radiologic findings. Maternal lifestyle and living conditions were investigated, and the maternal 25-OH vitamin D3 blood level was measured. We evaluated eight patients who developed heart failure as a result of severe hypocalcaemia associated with rickets between August, 1999 and June, 2012. The age distribution of the patients was 3-12 months. Laboratory results were consistent with advanced-stage rickets. Severe hypocalcaemia was detected in all patients. The maternal 25-OH vitamin D3 levels were low. Echocardiography revealed increased pre-treatment left ventricle end-systolic and end-diastolic diameters for age and reduced ejection fraction and fractional shortening. After clinical improvement, the patients were discharged. Severe hypocalcaemia associated with rickets must always be kept in mind among the causes of dilated cardiomyopathy and impaired cardiac function in infants. If diagnosed and treated in time, dilated cardiomyopathy and severe heart failure related to rickets respond well.

Current characteristics and management of congenital esophageal stenosis: 40 consecutive cases from a multicenter study in the Kyushu area of Japan.

PubMed

Suzuhigashi, Masaya; Kaji, Tatsuru; Noguchi, Hiroyuki; Muto, Mitsuru; Goto, Michiko; Mukai, Motoi; Nakame, Kazuhiko; Kawano, Takafumi; Yamada, Waka; Yamada, Koji; Onishi, Shun; Ieiri, Satoshi

2017-10-01

Congenital esophageal stenosis (CES) is rare, and the available clinical data are limited. We explored the current diagnosis, treatment and outcomes of CES. A questionnaire survey was performed using medical records at pediatric surgical centers in the Kyushu area. Over 10 years, 40 patients (24 males) had CES. The incidence of associated anomalies was 52.5% (21/40), and that of esophageal atresia was 20.0% (8/40). The mean age at the diagnosis was 12.0 months (range, 1 day-8.8 years). Seven (17.5%) patients were diagnosed in the neonatal period. Ten (25.0%) developed CES due to tracheobronchial remnants, 27 (67.5%) due to fibromuscular stenosis (FMS) and 1 (2.5%) due to membranous stenosis + FMS. Thirty-six (90.0%) were treated by balloon dilatation (mean, 3 times; range, 1-20). Perforation at dilatation occurred in 7 (17.5%) patients, and all were diagnosed with FMS. Eighteen (45.0%) patients underwent radical operation (3 primary, 15 secondary to dilatation). Our study clarified the characteristics and outcomes of CES, including neonatal diagnoses. CES occurred in 1 in every 33,000 births in the Kyushu area. Careful attention should be paid, even in cases of dilatation for FMS. CES requires long-term follow-up for symptom persistence after adequate and repeated treatment.

Increased plasma asymmetric dimethylarginine level is associated with ascending aorta dilatation: a case-control study.

PubMed

Satılmışoğlu, Muhammet Hulusi; Örnek Diker, Vesile; Taşbulak, Ömer; Diker, Mustafa; Birand, Ali; Kaya, Mehmet; İyigün, Taner; Eksik, Abdurrahman

2017-01-01

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase. We aimed to determine plasma ADMA levels in patients with ascending aorta dilatation in comparison to those without aorta dilatation, and to evaluate the diagnostic, predictive, and prognostic value of serum ADMA level for aorta dilatation. This was a cross-sectional case-control study. A total of 104 consecutive patients (female/male, 35/69; mean age, 62.75 ± 13.11 years) diagnosed with ascending aorta dilatation (≥ 4.5 cm) on echocardiography (case group), and 52 age-and gender-matched patients (female/male, 17/35; mean age, 63.44 ± 7.56 years) with normal aorta dimensions (≤ 3.8 cm) (control group) were included. Routine biochemical and haematological analysis in addition to measurement of serum ADMA level were performed. The mean diameter of ascending aorta measured on echocardiography was 4.95 ± 0.57 cm and 3.34 ± 0.36 cm in patients with aorta dilatation and those without aorta dilatation, respectively (p < 0.001). Serum ADMA level was significantly higher in patients with aorta dilatation than in the control group (1.70 ± 1.12 μmol/L vs. 0.79 ± 0.76 μmol/L, respectively, p < 0.001). There was significant positive correlation between ADMA level and aortic diameter in Spearman correlation analysis (r = 0.317, p < 0.001). In linear regression analysis, ADMA was found to be a significant independent predictor of aorta diameter (Beta = 0.26, p < 0.001). Receiver-operator characteristic curve analysis also revealed that serum ADMA cut-off level over 0.29 μmol/L predicts aorta dilatation (≥ 4.5 cm) with 94% sensitivity and 92% specificity and with high ac-curacy (area under curve: 0.786; 95% confidence interval: 0.709-0.863, p < 0.001). Serum ADMA level is diagnostic for ascending aorta dilatation with high sensitivity and specificity, and should be considered for use in clinical diagnosis of aorta dilatation.

Iris Crypts Influence Dynamic Changes of Iris Volume.

PubMed

Chua, Jacqueline; Thakku, Sri Gowtham; Tun, Tin A; Nongpiur, Monisha E; Tan, Marcus Chiang Lee; Girard, Michael J A; Wong, Tien Yin; Quah, Joanne Hui Min; Aung, Tin; Cheng, Ching-Yu

2016-10-01

To determine the association of iris surface features with iris volume change after physiologic pupil dilation in adults. Cross-sectional observational study. Chinese adults aged ≥ 50 years without ocular diseases. Digital iris photographs were taken from eyes of each participant and graded for crypts (by number and size) and furrows (by number and circumferential extent) following a standardized grading scheme. Iris color was measured objectively, using the Commission Internationale de l'Eclairage (CIE) L* color parameter (higher value denoting lighter iris). The anterior segment was imaged by swept-source optical coherence tomography (SS-OCT) (Casia; Tomey, Nagoya, Japan) under bright light and dark room conditions. Iris volumes in light and dark conditions were measured with custom semiautomated software, and the change in iris volume was quantified. Associations of the change in iris volume after pupil dilation with underlying iris surface features in right eyes were assessed using linear regression analysis. Iris volume change after physiologic pupil dilation from light to dark condition. A total of 65 Chinese participants (mean age, 59.8±5.7 years) had gradable data for iris surface features. In light condition, higher iris crypt grade was associated independently with smaller iris volume (β [change in iris volume in millimeters per crypt grade increment] = -1.43, 95% confidence interval [CI], -2.26 to -0.59; P = 0.001) and greater reduction of iris volume on pupil dilation (β [change in iris volume in millimeters per crypt grade increment] = 0.23, 95% CI, 0.06-0.40; P = 0.010), adjusting for age, gender, presence of corneal arcus, and change in pupil size. Iris furrows and iris color were not associated with iris volume in light condition or change in iris volume (all P > 0.05). Although few Chinese persons have multiple crypts on their irides, irides with more crypts were significantly thinner and lost more volume on pupil dilation. In view that the latter feature is known to be protective for acute angle-closure attack, it is likely that the macroscopic and microscopic composition of the iris is a contributing feature to angle-closure disease. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

NASA Astrophysics Data System (ADS)

Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

2015-03-01

To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

Evaluation of the Distribution of Paclitaxel After Application of a Paclitaxel-Coated Balloon in the Rabbit Urethra.

PubMed

Barbalias, Dimitrios; Lappas, Georgios; Ravazoula, Panagiotia; Liourdi, Despoina; Kyriazis, Iason; Liatsikos, Evangelos; Kallidonis, Panagiotis

2018-05-01

Urethral strictures are a common urologic problem that could require complex reconstructive procedures. Urethral dilatation represents a frequent practiced intervention associated with high recurrence rates. Drug-coated percutaneous angioplasty balloons (DCBs) with cytostatic drugs have been effectively used for the prevention of vascular restenosis after balloon dilatation. To reduce restenosis rates of urethral dilatation, these balloons could be used in the urethra. Nevertheless, the urothelium is different than the endothelium and these drugs may not be distributed to the outer layers of the urethra. Thus, an experiment was performed to evaluate the distribution of paclitaxel (PTX) in the rabbit urethra after the inflation of a PTX-coated balloon (PCB). Eleven rabbits underwent dilatation of the posterior urethra with common endoscopic balloons after urethrography. Nine of these rabbits were additionally treated with PCB. The urethras of the two control animals were removed along with three more dilated with PCB urethras immediately after the dilatation. The remaining of the urethras were removed after 24 (n = 3) and 48 hours (n = 3). The posterior segments of the urethras were evaluated with hematoxylin and eosin staining as well as with immunohistochemistry with polyclonal anti-PTX antibody. The two control specimens showed denudation of the urothelium after balloon dilatations and no PTX was observed. All specimens from dilated PCB urethras showed distribution of PTX to all layers of the urethra. The specimens that were immediately removed exhibited denudation of the urothelium without any inflammation. The specimens removed at 24 and 48 hours showed mild acute inflammation. PTX was distributed to the urothelial, submucosal, and smooth muscle layers of the normal rabbit urethra immediately after dilatation with a DCB. PTX and mild inflammation were present at the site 24 and 48 hours after the dilatation.

Acute limb heating improves macro- and microvascular dilator function in the leg of aged humans.

PubMed

Romero, Steven A; Gagnon, Daniel; Adams, Amy N; Cramer, Matthew N; Kouda, Ken; Crandall, Craig G

2017-01-01

Local heating of an extremity increases blood flow and vascular shear stress throughout the arterial tree. Local heating acutely improves macrovascular dilator function in the upper limbs of young healthy adults through a shear stress-dependent mechanism but has no such effect in the lower limbs of this age group. The effect of acute limb heating on dilator function within the atherosclerotic prone vasculature of the lower limbs of aged adults is unknown. Therefore, the purpose of this study was to test the hypothesis that acute lower limb heating improves macro- and microvascular dilator function within the leg vasculature of aged adults. Nine young and nine aged adults immersed their lower limbs at a depth of ~33 cm into a heated (~42°C) circulated water bath for 45 min. Before and 30 min after heating, macro (flow-mediated dilation)- and microvascular (reactive hyperemia) dilator functions were assessed in the lower limb, following 5 min of arterial occlusion, via Doppler ultrasound. Compared with preheat, macrovascular dilator function was unchanged following heating in young adults (P = 0.6) but was improved in aged adults (P = 0.04). Similarly, microvascular dilator function, as assessed by peak reactive hyperemia, was unchanged following heating in young adults (P = 0.1) but was improved in aged adults (P < 0.01). Taken together, these data suggest that acute lower limb heating improves both macro- and microvascular dilator function in an age dependent manner. We demonstrate that lower limb heating acutely improves macro- and microvascular dilator function within the atherosclerotic prone vasculature of the leg in aged adults. These findings provide evidence for a potential therapeutic use of chronic lower limb heating to improve vascular health in primary aging and various disease conditions. Copyright © 2017 the American Physiological Society.

Impairment of left ventricular function during coronary angioplastic occlusion evaluated with a nonimaging scintillation probe.

PubMed

Hartmann, A; Maul, F D; Zimny, M; Klepzig, H; Vallbracht, C; Kneissl, H G; Schräder, R; Hör, G; Kaltenbach, M

1991-09-01

Impairment of left ventricular function during controlled myocardial ischemia induced by coronary angioplasty has been reported from angiographic and echocardiographic studies. Ejection fraction, peak ejection, peak filling rates, and end-systolic and end-diastolic volumes were investigated before, during and after coronary occlusion on-line with a nonimaging scintillation probe. The study consisted of 18 patients (mean age 59 +/- 10 years) with coronary artery stenosis of greater than 70%. During balloon inflation of 60 seconds' duration, coronary occlusion pressure was 31.6 +/- 12 mm Hg. There was no significant change in heart rate. Delay between first and second dilatation was 109 +/- 63 seconds. Ejection fraction decreased from 53 +/- 16 to 40 +/- 12% (first dilatation, p less than 0.01) and to 39 +/- 14% (second dilatation, p less than 0.01) and recovered to 51 +/- 16% 5 minutes after the second dilatation. Peak ejection rate was significantly reduced during the first and second balloon inflations. Peak filling rate decreased from 2.5 +/- 0.8 to 2.0 +/- 0.7 end-diastolic volume.s-1 (first dilatation, p less than 0.01) and to 1.8 +/- 0.7 end-diastolic volume.s-1 (second dilatation, p less than 0.01) and remained reduced at 2.2 +/- 0.7 end-diastolic volume.s-1 (p = not significant) at 5 minutes after the second dilatation. End-systolic and end-diastolic volumes increased significantly during the first and second dilatations and returned to normal after dilatation. It is concluded that short, controlled myocardial ischemia during coronary angioplasty leads to a decrease in systolic and diastolic left ventricular function. Sequential dilatations do not further decrease function if a sufficient interval is kept.

Varicocele and concomitant dilation of the periprostatic venous plexus: effects on semen viscosity sperm parameters.

PubMed

Condorelli, R A; Calogero, A E; Mongioi', L; Vicari, E; Russo, G I; Lanzafame, F; La Vignera, S

2016-05-01

Since varicocele is often associated with other venous abnormalities, this study was undertaken to evaluate the frequency of dilation of the periprostatic venous plexus (DPVP) in these patients and the effects of this association on sperm parameters before and after varicocelectomy. Sperm parameters were evaluated using the conventional WHO criteria, and seminal fluid viscosity was further evaluated by quantitative viscometry, in 50 patients (aged 20-38 years) who underwent surgical treatment for grade III bilateral varicocele. Thirty patients with varicocele had also DPVP (DPVP+) (60 %). Sperm concentration and the percentage of spermatozoa with normal morphology did not differ significantly in patients with DPVP- or DPVP+ before or after surgical repair. On the other hand, sperm progressive motility was low in all patients and increased significantly after varicocele repair, but only in DPVP- patients. Before varicocele treatment, a significantly higher number of DPVP+ patients (25/30 = 83.3 %) had seminal fluid hyperviscosity compared to DPVP- patient (2/20 = 10.0 %). Viscosity quantitative measurement was significantly higher in DPVP+ patients both before and after varicocele repair compared to DPVP- patients. These latter showed a statistically significant reduction of sperm viscosity after varicocele surgical repair compared to pretreatment values. Finally, periprostatic venous plexus diameter and seminal fluid viscosity correlated directly in DPVP+ patients. In conclusion, these results showed that a large number of patients with varicocele had a concomitant DPVP. This subset of patients did not take advantage from varicocele surgical repair since only DPVP- varicocele patients showed a significant improvement of sperm progressive motility and seminal fluid viscosity. These findings suggest the evaluation of the periprostatic venous plexus and seminal fluid viscosity before patients with varicocele undergo surgical repair for asthenozoospemia.

Evaluation of right ventricular function using liver stiffness in patients with left ventricular assist device.

PubMed

Kashiyama, Noriyuki; Toda, Koichi; Nakamura, Teruya; Miyagawa, Shigeru; Nishi, Hiroyuki; Yoshikawa, Yasushi; Fukushima, Satsuki; Saito, Shunsuke; Yoshioka, Daisuke; Sawa, Yoshiki

2017-04-01

Although right ventricular failure (RVF) is a major concern after left ventricular assist device (LVAD) implantation, methodologies to evaluate RV function remain limited. Liver stiffness (LS), which is closely related to right-sided filling pressure and may indicate RVF severity, could be non-invasively and repeatedly assessed using transient elastography. Here we investigated the suitability of LS as a parameter of RV function in pre- and post-LVAD periods. The study included 55 patients with LVAD implantation as a bridge to transplantation between 2011 and 2015 whose LS was assessed using transient elastography. Seventeen patients presented with RVF, defined as requiring inotropic support for ≥30 days, nitric oxygen inhalation for ≥5 days, and/or mechanical RV support following LVAD implantation. Survival of patients with RVF was significantly worse compared with that of patients without RVF. Multivariate logistic regression analysis identified preoperative LS, LV diastolic dimension, RV stroke work index, and dilated phase of hypertrophic cardiomyopathy aetiology as significant risk factors; the combination of these parameters could improve predictive power of post-LVAD RVF with areas under the curve of 0.89. Furthermore, LS was significantly decreased by LV unloading and significantly correlated with right-sided filling pressure. In addition to dilated hypertrophic cardiomyopathy aetiology, reduced RV stroke work index and small LV dimension, we demonstrated that non-invasively measured LS was a predictor of post-LVAD RVF and can be used as a parameter for the evaluation and optimization of RV function in the perioperative period. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.

Mechanics of dual-mode dilative failure in subaqueous sediment deposits

NASA Astrophysics Data System (ADS)

You, Yao; Flemings, Peter; Mohrig, David

2014-07-01

We introduce dual-mode dilative failure with flume experiments. Dual-mode dilative failure combines slow and steady release of sediments by breaching with periodic sliding, which rapidly releases an internally coherent wedge of sediments. It occurs in dilative sandy deposits. This periodic slope failure results from cyclic evolution of the excess pore pressure in the deposit. Sliding generates large, transient, negative excess pore pressure that strengthens the deposit and allows breaching to occur. During breaching, negative excess pore pressure dissipates, the deposit weakens, and ultimately sliding occurs once again. We show that the sliding frequency is proportional to the coefficient of consolidation. We find that thicker deposits are more susceptible to dual-mode dilative failure. Discovery of dual-mode dilative failure provides a new mechanism to consider when interpreting the sedimentary deposits linked to submarine slope failures.

Office dilation of the female urethra: a quality of care problem in the field of urology.

PubMed

Santucci, Richard A; Payne, Christopher K; Anger, Jennifer T; Saigal, Christopher S

2008-11-01

Historically dilation of the female urethra was thought to be of value in the treatment of a variety of lower urinary tract symptoms. Subsequent work has more accurately classified these complaints as parts of various diseases or syndromes in which scant data exist to support the use of dilation. Yet Medicare reimbursement for urethral dilation remains generous and we describe practice patterns regarding female urethral dilation to characterize a potential quality of care issue. Health care use by females treated with urethral dilation was compiled using a complementary set of databases. Data sets were examined for relevant inpatient, outpatient and emergency room services for women of all ages. Female urethral dilation is common (929 per 100,000 patients) and is performed almost as much as treatment for male urethral stricture disease. Approximately 12% of these patients are subjected to costly studies such as retrograde urethrography. The overall national costs for treatment exceed $61 million per year and have increased 10% to 17% a year since 1994. A diagnosis of female urethral stricture increases health care expenditures by more than $1,800 per individual per year in insured populations. Urethral dilation is still common despite the fact that true female urethral stricture is an uncommon entity. This scenario is likely secondary to the persistence of the mostly discarded practice of dilating the unstrictured female urethra for a wide variety of complaints despite the lack of data suggesting that it improves lower urinary tract symptoms.

Effects of supramaximal balloon dilatation pressures on adult cricoid and tracheal cartilage: A cadaveric study.

PubMed

Durvasula, Venkata S P B; Shalin, Sara C; Tulunay-Ugur, Ozlem E; Suen, James Y; Richter, Gresham T

2018-06-01

Cricoid fracture is a serious concern for balloon dilatation in airway stenosis. Furthermore, there are no studies examining tracheal rupture in balloon dilatation of stenotic segments. The aim of this study was to evaluate the effect of supramaximal pressures of balloons on the cricoid and tracheal rings. Prospective cadaveric study. Seven cadaveric laryngotracheal complexes of normal adults with intact cricothyroid membranes were acquired. Noncompliant vascular angioplasty balloons (BARD-VIDA) were used for dilatation. The subglottis and trachea were subjected to supramaximal dilatation pressures graduated to nominal burst pressure (NBP) and, if necessary, rated burst pressure (RBP). Larger-diameter balloons, starting from 18 mm size to 24 mm, were used. Dilatations were maintained for 3 minutes. The cricoid ring was disrupted by larger-diameter balloons (22 mm and 24 mm) even at lower pressures (less than NBP) in six cases. Tracheal cartilages were very distensible, and external examination after supramaximal dilatation (24 mm close to RBP) revealed no obvious cartilage fractures or trachealis tears. Histopathological examination revealed sloughing of mucosa in the areas corresponding to balloon placement, but no microfractures or disruption of the perichondrium of tracheal ring cartilages. These results indicate that the cricoid is vulnerable to injury from larger balloons even at lower dilatation pressures. The tracheal cartilages and the membranous wall of the trachea remained resilient to supramaximal dilatation and larger balloons. NA. Laryngoscope, 128:1304-1309, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Emergency Physicians Are Able to Detect Right Ventricular Dilation With Good Agreement Compared to Cardiology.

PubMed

Rutz, Matt A; Clary, Julie M; Kline, Jeffrey A; Russell, Frances M

2017-07-01

Focused cardiac ultrasound (FOCUS) is a useful tool in evaluating patients presenting to the emergency department (ED) with acute dyspnea. Prior work has shown that right ventricular (RV) dilation is associated with repeat hospitalizations and shorter life expectancy. Traditionally, RV assessment has been evaluated by cardiologist-interpreted comprehensive echocardiography. The primary goal of this study was to determine the inter-rater reliability between emergency physicians (EPs) and a cardiologist for determining RV dilation on FOCUS performed on ED patients with acute dyspnea. This was a prospective, observational study at two urban academic EDs; patients were enrolled if they had acute dyspnea and a computed tomographic pulmonary angiogram without acute disease. All patients had an EP-performed FOCUS to assess for RV dilation. RV dilation was defined as an RV to left ventricular ratio greater than 1. FOCUS interpretations were compared to a blinded cardiologist FOCUS interpretation using agreement and kappa statistics. Of 84 FOCUS examinations performed on 83 patients, 17% had RV dilation. Agreement and kappa, for EP-performed FOCUS for RV dilation were 89% (95% confidence interval [CI] 80-95%) and 0.68 (95% CI 0.48-0.88), respectively. Emergency physician sonographers are able to detect RV dilation with good agreement when compared to cardiology. These results support the wider use of EP-performed FOCUS to evaluate for RV dilation in ED patients with dyspnea. © 2017 by the Society for Academic Emergency Medicine.

Histopathology of balloon-dilation Eustachian tuboplasty.

PubMed

Kivekäs, Ilkka; Chao, Wei-Chieh; Faquin, William; Hollowell, Monica; Silvola, Juha; Rasooly, Tali; Poe, Dennis

2015-02-01

Surgical intervention of the Eustachian tube (ET) has become increasingly common in the past decade, and balloon dilation has shown promising results in recent studies. It is unclear how balloon dilation enhances ET function. Our aim was to evaluate histological changes in the ET's mucosal lumen comparing before balloon dilation, immediately after, and postoperatively. Case series. Thirteen patients with bilateral ET dysfunction were enrolled. Biopsies of the ET mucosa were obtained just before balloon dilation; immediately after; and in three cases, 5 to 12 weeks postoperatively. Specimens were retrospectively examined under light microscopy by two pathologists blinded to the clinical information and whether specimens were pre- or postballoon dilation. Preoperative biopsies were characterized by inflammatory changes within the epithelium and submucosal layer. Immediate response to balloon dilation was thinning of the mucosa, shearing of epithelium and crush injury to the submucosa, especially to lymphocytic infiltrates. Postoperative biopsies demonstrated healthy pseudocolumnar epithelium and replacement of lymphocytic infiltrate with a thinner layer of fibrous tissue. Reduction of inflammatory epithelial changes and submucosal inflammatory infiltrate appeared to be the principal result of balloon dilation. The balloon may shear or crush portions of inflamed epithelium but usually spared the basal layer, allowing for rapid healing. Additionally, it appeared to effectively crush lymphocytes and lymphocytic follicles that may become replaced with thinner fibrous scar. Histopathology of the ET undergoing balloon dilation demonstrated effects that could reduce the overall inflammatory burden and may contribute to clinical improvement in ET function. 4. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Crucial importance of the endothelial K+ channel SK3 and connexin40 in arteriolar dilations during skeletal muscle contraction.

PubMed

Milkau, Malte; Köhler, Ralf; de Wit, Cor

2010-09-01

Skeletal muscle activity requires substantial increases in blood flow, and the underlying vasodilation involves endothelial activity, but the contribution of the endothelium-dependent hyperpolarizing factor (EDHF) is only poorly defined. In EDHF signaling, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels SK3 and IK1 is a key step and also initiates gap junction-dependent conducted dilations. We assessed the role of SK3, IK1, and connexin40 (Cx40) in muscular contraction-induced dilations in the microcirculation in vivo. Hitherto, arterioles were observed in the electrically stimulated cremaster skeletal muscle of anesthetized mice lacking SK3, IK1, or Cx40 using intravital microscopy. Genetic deficiency of SK3, but not of IK1, strongly attenuated dilations to muscular contraction. Similarly, pharmacologic blockade of SK3 by the specific blocker UCL1684 impaired such dilations in wild-type and IK1-deficient mice. In contrast, IK1 was required for acetylcholine-induced dilations. Genetic deficiency of Cx40 also attenuated dilations induced by muscular contraction but not by acetylcholine. These data support the concept that endothelial hyperpolarization through activation of SK3 contributes to exercise hyperemia and the hyperpolarization ascends the vascular tree through gap junctions formed by Cx40 to orchestrate dilation. The differential impact of SK3- and IK1-deficiency on dilations to distinct stimuli suggests stimulus-dependent activation of these endothelial channels.

Gastric Necrosis due to Acute Massive Gastric Dilatation.

PubMed

Aydin, Ibrahim; Pergel, Ahmet; Yucel, Ahmet Fikret; Sahin, Dursun Ali; Ozer, Ender

2013-01-01

Gastric necrosis due to acute massive gastric dilatation is relatively rare. Vascular reasons, herniation, volvulus, acute gastric dilatation, anorexia, and bulimia nervosa play a role in the etiology of the disease. Early diagnosis and treatment are highly important as the associated morbidity and mortality rates are high. In this case report, we present a case of gastric necrosis due to acute gastric dilatation accompanied with the relevant literature.

Gastric Necrosis due to Acute Massive Gastric Dilatation

PubMed Central

Pergel, Ahmet; Yucel, Ahmet Fikret; Sahin, Dursun Ali; Ozer, Ender

2013-01-01

Gastric necrosis due to acute massive gastric dilatation is relatively rare. Vascular reasons, herniation, volvulus, acute gastric dilatation, anorexia, and bulimia nervosa play a role in the etiology of the disease. Early diagnosis and treatment are highly important as the associated morbidity and mortality rates are high. In this case report, we present a case of gastric necrosis due to acute gastric dilatation accompanied with the relevant literature. PMID:23983714

Pre- and post-treatment urinary tract findings in children with nephrogenic diabetes insipidus.

PubMed

Caletti, María Gracia; Balestracci, Alejandro; Di Pinto, Diana

2014-03-01

Nephrogenic diabetes insipidus (NDI) is characterized by the kidney's inability to concentrate urine, which causes intense polyuria that may lead to urinary tract dilation. We report the morphological findings of the urinary tract in ten boys with NDI specifically addressing the presence and changes of urinary tract dilation during treatment. Patients were diagnosed at a median age of 1.6 years (range, 0.16-6.33 years) and treated with a low osmotic diet, hydrochlorothiazide-amiloride and indomethacin, which decreased the diuresis from a median of 10.5 ml/kg/h to 4.4 ml/kg/h (p < 0.001). Three patients showed normal renal ultrasound before treatment until last control, while the remaining seven showed urinary tract dilation. In this second group, dilation was reduced with treatment in four patients and disappeared in the remaining three. Children without dilation or in whom the dilation disappeared were diagnosed and treated earlier than those with persistent dilation (median 1.66 versus 4.45 years, respectively). After a median of 10.4 (range, 2.3-20.3) years of follow-up, no patients showed urological complications. Medical treatment of the disease improved the dilation in all cases, preventing its potential complications. Regardless of the good outcome of our patients, periodic urologic follow-up is recommended in NDI patients.

Endoscopic Balloon Dilatation of Benign Esophageal Stricture—A Nonhazardous Procedure?

PubMed Central

Borgström, Anders; Fork, Frans-Thomas; Lövdahl, Eje

1994-01-01

Balloon dilatation of benign esophageal strictures has been widely used since its introduction. We have performed 224 dilatation procedures in 52 patients. Dilatation was done as an outpatient procedure. Strictures were due to reflux esophagitis in 25 patients, anastomatic stenosis in 6, achalasia in 5, complications of sclerotherapy in 5, corrosive lesions in 3, and long-standing nasogastric intubation in 2. The cause was unknown in 6 cases. The intention was to dilate all strictures up to 20 mm. Three major complications occurred, and one of these patients died. The risk of perforation seems to be higher after repeated procedures than during the first one. PMID:18493348

Natural genetic variation of the cardiac transcriptome in non-diseased donors and patients with dilated cardiomyopathy.

PubMed

Heinig, Matthias; Adriaens, Michiel E; Schafer, Sebastian; van Deutekom, Hanneke W M; Lodder, Elisabeth M; Ware, James S; Schneider, Valentin; Felkin, Leanne E; Creemers, Esther E; Meder, Benjamin; Katus, Hugo A; Rühle, Frank; Stoll, Monika; Cambien, François; Villard, Eric; Charron, Philippe; Varro, Andras; Bishopric, Nanette H; George, Alfred L; Dos Remedios, Cristobal; Moreno-Moral, Aida; Pesce, Francesco; Bauerfeind, Anja; Rüschendorf, Franz; Rintisch, Carola; Petretto, Enrico; Barton, Paul J; Cook, Stuart A; Pinto, Yigal M; Bezzina, Connie R; Hubner, Norbert

2017-09-14

Genetic variation is an important determinant of RNA transcription and splicing, which in turn contributes to variation in human traits, including cardiovascular diseases. Here we report the first in-depth survey of heart transcriptome variation using RNA-sequencing in 97 patients with dilated cardiomyopathy and 108 non-diseased controls. We reveal extensive differences of gene expression and splicing between dilated cardiomyopathy patients and controls, affecting known as well as novel dilated cardiomyopathy genes. Moreover, we show a widespread effect of genetic variation on the regulation of transcription, isoform usage, and allele-specific expression. Systematic annotation of genome-wide association SNPs identifies 60 functional candidate genes for heart phenotypes, representing 20% of all published heart genome-wide association loci. Focusing on the dilated cardiomyopathy phenotype we found that eQTL variants are also enriched for dilated cardiomyopathy genome-wide association signals in two independent cohorts. RNA transcription, splicing, and allele-specific expression are each important determinants of the dilated cardiomyopathy phenotype and are controlled by genetic factors. Our results represent a powerful resource for the field of cardiovascular genetics.

Slip and Dilation Tendency Analysis of the Patua Geothermal Area

DOE Data Explorer

Faulds, James E.

2013-12-31

Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = τ / σn (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (σ1-σn) / (σ1-σ3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Slip and dilation tendency analysis for the Patua geothermal system was calculated based on faults mapped in the Hazen Quadrangle (Faulds et al., 2011). Patua lies near the margin between the Basin and Range province, which is characterized by west-northwest directed extension and the Walker Lane province, characterized by west-northwest directed dextral shear. As such, the Patua area likely has been affected by tectonic stress associated with either or both of stress regimes over geologic time. In order to characterize this stress variation we calculated slip tendency at Patua for both normal faulting and strike slip faulting stress regimes. Based on examination of regional and local stress data (as explained above) we applied at shmin direction of 105 to Patua. Whether the vertical stress (sv) magnitude is larger than ...

Achalasia-Specific Quality of Life After Pneumatic Dilation or Laparoscopic Heller Myotomy With Partial Fundoplication: A Multicenter, Randomized Clinical Trial.

PubMed

Chrystoja, Caitlin C; Darling, Gail E; Diamant, Nicholas E; Kortan, Paul P; Tomlinson, George A; Deitel, Wayne; Laporte, Audrey; Takata, Julie; Urbach, David R

2016-11-01

Achalasia is a chronic, progressive, and incurable esophageal motility disease. There is clinical uncertainty about which treatment should be recommended as first-line therapy. Our objective was to evaluate the effectiveness of pneumatic dilation compared with laparoscopic Heller myotomy with partial fundoplication in improving achalasia-specific quality of life. This was a prospective, multicenter, randomized trial at five academic hospitals in Canada. Fifty previously untreated adults with a clinical diagnosis of primary achalasia, confirmed by manometric testing, were enrolled between November 2005 and March 2010, and followed for 5 years after treatment. Randomization was stratified by site, in random blocks of size four and with balanced allocation. Patients were treated with pneumatic dilation or laparoscopic Heller myotomy with partial fundoplication. The primary outcome was the difference between the treatments in the mean improvement of the achalasia severity questionnaire (ASQ) score at 1 year from baseline. Prespecified secondary outcomes included general and gastrointestinal quality of life, symptoms, esophageal physiology measures (lower esophageal sphincter relaxation and pressure, esophageal emptying, abnormal esophageal acid exposure), complications, and incidence of retreatment. Functional and imaging studies were performed blinded and all outcome assessors were blinded. There were no significant differences between treatments in the improvement of ASQ score at 1 year from baseline (27.5 points in the Heller myotomy arm vs. 20.2 points in the pneumatic dilation arm; difference 7.3 points, 95% confidence interval -4.7 to 19.3; P=0.23). There were no differences between treatments in improvement of symptoms, general and gastrointestinal quality of life, or measures of esophageal physiology. Improvements in ASQ score diminished over time for both interventions. At 5 years, there were no differences between treatments in improvement of ASQ score, symptoms, and general or gastrointestinal quality of life. There were no serious adverse events. No patient who received Heller myotomy required retreatment, whereas five patients treated initially with pneumatic dilation required retreatment. Treatment with pneumatic dilation or laparoscopic Heller myotomy similarly improves achalasia-specific disease severity at 1 year. Either of the therapeutic approaches can be used as first-line therapy for previously untreated adults with achalasia.

Post-stimulus potentiation of transmission in pelvic ganglia enhances sympathetic dilatation of guinea-pig uterine artery in vitro

PubMed Central

Morris, Judy L; Gibbins, Ian L; Jobling, Phillip

2005-01-01

Vasodilatation produced by stimulation of preganglionic neurones in lumbar and sacral pathways to pelvic ganglia was studied using an in vitro preparation of guinea-pig uterine artery and associated nerves in a partitioned bath allowing selective drug application to the ganglia or artery. Arterial diameter was monitored using real time video imaging. Vasodilatations produced by hypogastric nerve stimulation (HN; 300 pulses, 10 Hz) were significantly larger and longer in duration than with pelvic nerve stimulation (N = 18). Stimulation of ipsilateral lumbar splanchnic nerves or ipsilateral third lumbar ventral roots also produced prolonged vasodilatations. Blockade of ganglionic nicotinic receptors (0.1–1 mm hexamethonium) delayed the onset and sometimes reduced the peak amplitude of dilatations, but slow dilatations persisted in 16 of 18 preparations. These dilatations were not reduced further by 3 μm capsaicin applied to the artery and ganglia, or ganglionic application of 1 μm hyoscine, 30–100 μm suramin or 10 μm CNQX. Dilatations were reduced slightly by ganglionic application of NK1 and NK3 receptor antagonists (SR140333, SR142801; 1 μm), but were reduced significantly by bathing the ganglia in 0.5 mm Ca2+ and 10 mm Mg2+. Intracellular recordings of paracervical ganglion neurones revealed fast excitatory postsynaptic potentials (EPSPs) in all neurones on HN stimulation (300 pulses, 10 Hz), and slow EPSPs (3–12 mV amplitude) in 25 of 37 neurones. Post-stimulus action potential discharge associated with slow EPSPs occurred in 16 of 37 neurones (firing rate 9.4 ± 1.5 Hz). Hexamethonium (0.1–1 mm) abolished fast EPSPs. Hexamethonium and hyoscine (1 μm) did not reduce slow EPSPs and associated post-stimulus firing in identified vasodilator neurones (with VIP immunoreactivity) or non-vasodilator paracervical neurones. These results demonstrate a predominantly sympathetic origin of autonomic pathways producing pelvic vasodilatation in females. Non-cholinergic mediators of slow transmission in pelvic ganglia produce prolonged firing of postganglionic neurones and long-lasting dilatations of the uterine artery. This mechanism would facilitate maintenance of pelvic vasodilatation on stimulation of preganglionic neurones during sexual activity. PMID:15802294

Foley catheter placement for induction of labor with or without stylette: a randomized clinical trial.

PubMed

Forgie, Marie M; Greer, Danielle M; Kram, Jessica J F; Vander Wyst, Kiley B; Salvo, Nicole P; Siddiqui, Danish S

2016-03-01

Foley catheters are used for cervical ripening during induction of labor. Previous studies suggest that use of a stylette (a thin, rigid wire) to guide catheter insertion decreases insertion failure. However, stylette effects on insertion outcomes have been sparsely studied. The purpose of this study was to compare catheter insertion times, patient-assessed pain levels, and insertion failure rates between women who received a digitally placed Foley catheter for cervical ripening with the aid of a stylette and women who received the catheter without a stylette. We conducted a randomized clinical trial of women aged ≥ 18 years who presented for induction of labor. Inclusion criteria were singletons with intact membranes and cephalic presentation. Women received a computer-generated random assignment of a Foley catheter insertion with a stylette (treatment group, n = 62) or without a stylette (control group, n = 61). For all women, a standard insertion technique protocol was used. Three primary outcomes were of interest, including the following: (1) insertion time (total minutes to successful catheter placement), (2) patient-assessed pain level (0-10), and (3) failure rate of the randomly assigned insertion method. Treatment control differences were first examined using the Pearson's test of independence and the Student t test. Per outcome, we also constructed 4 regression models, each including the random effect of physician and fixed effects of stylette use with patient nulliparity, a history of vaginal delivery, cervical dilation at presentation, or postgraduate year of the performing resident physician. Women who received the Foley catheter with the stylette vs without the stylette did not differ by age, race/ethnicity, body mass index, or any of several other characteristics. Regression models revealed that insertion time, patient pain, and insertion failure were unrelated to stylette use, nulliparity, and history of vaginal delivery. However, overall insertion time and failure were significantly influenced by cervical dilation, with insertion time decreasing by 21% (95% confidence interval [CI], 5-34%) and odds of failure decreasing by 71% (odds ratio, 0.29; 95% CI, 0.10-0.86) per 1 cm dilation. Resident postgraduate year also significantly influenced insertion time, with greater time required of physicians with less experience. Mean insertion time was 51% (95% CI, 23-69%) shorter for fourth-year than second-year residents. Statistically nonsignificant but prominent patterns in outcomes were also observed, suggesting stylette use may lengthen the overall insertion procedure but minimize variability in pain levels and decrease insertion failure. The randomized trial suggests that, even after accounting for nulliparity, history of vaginal delivery, cervical dilation, and physician experience, Foley catheter insertions with and without a stylette are equivalent in insertion times, patient pain levels, and failure of catheter placement. Copyright © 2016 Elsevier Inc. All rights reserved.

Modern treatment of oesophageal strictures.

PubMed

Eastman, M C; Sali, A

1980-02-09

The results of 185 dilatations of oesophageal strictures with the rigid oesophagoscope are reported. The complication rate was 6%, which included five perforations (2.7%), and one death. The new technique of Eder-Puestow wire-guided dilatation was used in 20 cases without complication. These results, together with other reported experience of Eder-Puestow dilatation, suggest that this technique is superior to that of rigid dilatation on the grounds both of safety and of cost.

The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

PubMed Central

Rieger, Gerulf; Savin-Williams, Ritch C.

2012-01-01

Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research. PMID:22870196

Small Intestinal Submucosa Plug for Closure of Dilated Nephrostomy Tracts: A Pilot Study in Swine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kakizawa, Hideyaki; Conlin, M. J.; Pavcnik, Dusan, E-mail: pavcnikd@ohsu.edu

2010-06-15

The aim of this study was to evaluate efficacy of a plug made of small intestinal submucosa (SIS) for closure of dilated nephrostomy tract in the kidney after nephroscopy. Ten kidneys in 5 swine had nephrostomy tracts dilated up to 8 mm. The SIS plug was placed into the dilated renal cortex under nephroscopic control. Follow-up arteriograms, retrograde pyelograms, and macroscopic and histologic studies at 24 h (n = 4), 6 weeks (n = 2), and 3 months (n = 4) were performed to evaluate the efficacy of the plug. The SIS plug effectively closed the dilated nephrostomy tract. Follow-upmore » studies showed minimal changes of the kidneys, except for 1 small infarction, regarding inflammatory and foreign-body reactions and progressive scarring of the SIS. SIS plug is effective for occlusion of dilated nephrostomy tract after nephroscopy. Its efficacy should be compared with other therapeutic options.« less

Role of endoscopic biliary drainage in advanced hepatocellular carcinoma with jaundice

PubMed Central

Han, Sung Yong; Heo, Jeong; Kim, Dong Uk; Baek, Dong Hoon; Yoo, So Yong; Kim, Chang Won; Kim, Suk; Song, Geun Am; Cho, Mong; Kang, Dae Hwan

2017-01-01

Background Patients with advanced hepatocellular carcinoma (HCC) with jaundice have an extremely poor prognosis. Although biliary drainage can resolve obstructive jaundice, signs of obstruction may not be evident. This study evaluated the role of endoscopic biliary drainage in patients with advanced HCC and obstructive jaundice. Methods From 2010 to 2015, 74 patients underwent endoscopic biliary drainage for obstructive jaundice due to advanced HCC. Jaundice resolution was defined as complete response and total bilirubin concentration below 3 mg/dl. Results The technical success rate in the 74 patients was 92.1% (70/76). Of the 70 patients who underwent successful biliary drainage, 48 (68.6%) and 22 (31.4%) were Child-Pugh classes B and C, respectively, and 10 (14.3%) and 60 (85.7%) were BCLC stages B and C, respectively. Intrahepatic bile duct (IHD) dilatation was observed in 35 patients (50%). After drainage, the complete response rate was 35.7% (25/70). The mean time to resolution was 17.4 ±8.5 days. However, jaundice was re-aggravated in 74.3% (15/25) after a mean 103.5 ±96.4 days. Multivariate analysis showed that the absence of ascites, presence of IHD dilatation, normal range of prothrombin time, and lower MELD score were significantly associated with complete response. The overall survival rate was 15.7% (11/70) and the median survival time is 28 days (95% confidence interval 2.6–563 days). Complete response and HCC treatment after drainage were significantly associated with survival. Conclusion Effective endoscopic biliary drainage is an important palliative treatment in patients with advanced HCC and obstructive jaundice, especially those with IHD dilatation and preserved liver function, as determined by ascites, prothrombin time, and MELD score. PMID:29095941

Role of endoscopic biliary drainage in advanced hepatocellular carcinoma with jaundice.

PubMed

Woo, Hyun Young; Han, Sung Yong; Heo, Jeong; Kim, Dong Uk; Baek, Dong Hoon; Yoo, So Yong; Kim, Chang Won; Kim, Suk; Song, Geun Am; Cho, Mong; Kang, Dae Hwan

2017-01-01

Patients with advanced hepatocellular carcinoma (HCC) with jaundice have an extremely poor prognosis. Although biliary drainage can resolve obstructive jaundice, signs of obstruction may not be evident. This study evaluated the role of endoscopic biliary drainage in patients with advanced HCC and obstructive jaundice. From 2010 to 2015, 74 patients underwent endoscopic biliary drainage for obstructive jaundice due to advanced HCC. Jaundice resolution was defined as complete response and total bilirubin concentration below 3 mg/dl. The technical success rate in the 74 patients was 92.1% (70/76). Of the 70 patients who underwent successful biliary drainage, 48 (68.6%) and 22 (31.4%) were Child-Pugh classes B and C, respectively, and 10 (14.3%) and 60 (85.7%) were BCLC stages B and C, respectively. Intrahepatic bile duct (IHD) dilatation was observed in 35 patients (50%). After drainage, the complete response rate was 35.7% (25/70). The mean time to resolution was 17.4 ±8.5 days. However, jaundice was re-aggravated in 74.3% (15/25) after a mean 103.5 ±96.4 days. Multivariate analysis showed that the absence of ascites, presence of IHD dilatation, normal range of prothrombin time, and lower MELD score were significantly associated with complete response. The overall survival rate was 15.7% (11/70) and the median survival time is 28 days (95% confidence interval 2.6-563 days). Complete response and HCC treatment after drainage were significantly associated with survival. Effective endoscopic biliary drainage is an important palliative treatment in patients with advanced HCC and obstructive jaundice, especially those with IHD dilatation and preserved liver function, as determined by ascites, prothrombin time, and MELD score.

The NIST 27 Al+ quantum-logic clock

NASA Astrophysics Data System (ADS)

Leibrandt, David; Brewer, Samuel; Chen, Jwo-Sy; Hume, David; Hankin, Aaron; Huang, Yao; Chou, Chin-Wen; Rosenband, Till; Wineland, David

2016-05-01

Optical atomic clocks based on quantum-logic spectroscopy of the 1 S0 <--> 3 P0 transition in 27 Al+ have reached a systematic fractional frequency uncertainty of 8 . 0 ×10-18 , enabling table-top tests of fundamental physics as well as measurements of gravitational potential differences. Currently, the largest limitations to the accuracy are second order time dilation shifts due to the driven motion (i.e., micromotion) and thermal motion of the trapped ions. In order to suppress these shifts, we have designed and built new ion traps based on gold-plated, laser-machined diamond wafers with differential RF drive, and we have operated one of our clocks with the ions laser cooled to near the six mode motional ground state. We present a characterization of the time dilation shifts in the new traps with uncertainties near 1 ×10-18 . Furthermore, we describe a new protocol for clock comparison measurements based on synchronous probing of the two clocks using phase-locked local oscillators, which allows for probe times longer than the laser coherence time and avoids the Dick effect. This work is supported by ARO, DARPA, and ONR.

Comparison of Hb-200 and 6% hetastarch 450/0.7 during initial fluid resuscitation of 20 dogs with gastric dilatation-volvulus.

PubMed

Haak, Carol E; Rudloff, Elke; Kirby, Rebecca

2012-04-01

To compare the use of polymerized stroma-free bovine hemoglobin (Hb-200) and 6% hetastarch 450/0.7 (HES 450/0.7) in 0.9% saline during fluid resuscitation of dogs with gastric dilatation-volvulus (GDV). Prospective, randomized clinical case series. Private specialty and referral clinic. Twenty client-owned dogs presenting with GDV. Dogs presenting with GDV and abnormal perfusion parameters first received rapid IV infusion of a buffered isotonic replacement crystalloid (15 mL/kg) and IV opioids. Patients were then randomized to receive either Hb-200 (N = 10) or HES 450/0.7 (N = 10). Balanced isotonic replacement crystalloids (10-20 mL/kg IV) were rapidly infused along with either Hb-200 or HES in 5 mL/kg IV aliquots to meet resuscitation end points. Resuscitation was defined as meeting at least 2 of 3 criteria: (1) capillary refill time 1-2 seconds, pink mucous membrane color, strong femoral pulse quality; (2) heart rate (HR) ≤ 150/min; or (3) indirect arterial systolic blood pressure (SBP) > 90 mm Hg. HR, SBP, packed cell volume, hemoglobin, glucose, venous pH, bicarbonate, base excess, anion gap, and colloid osmotic pressure were compared at hospital entry and within 30 minutes post-resuscitation. Compared to the HES group, the Hb-200 group required significantly less colloid (4.2 versus 18.4 mL/kg) and crystalloid (31.3 versus 48.1 mL/kg) to reach resuscitation end points (P = 0.001). Time to resuscitation was significantly shorter in the Hb-200 group (12.5 versus 52.5 min). Dogs with GDV receiving Hb-200 during initial resuscitation required smaller volumes of both crystalloid and colloid fluids and reached resuscitation end points faster than dogs receiving HES 450/0.7 (P = 0.02). © Veterinary Emergency and Critical Care Society 2012.

Memory for incidentally perceived social cues: Effects on person judgment.

PubMed

Pawling, Ralph; Kirkham, Alexander J; Tipper, Steven P; Over, Harriet

2017-02-01

Dynamic face cues can be very salient, as when observing sudden shifts of gaze to a new location, or a change of expression from happy to angry. These highly salient social cues influence judgments of another person during the course of an interaction. However, other dynamic cues, such as pupil dilation, are much more subtle, affecting judgments of another person even without awareness. We asked whether such subtle, incidentally perceived, dynamic cues could be encoded in to memory and retrieved at a later time. The current study demonstrates that in some circumstances changes in pupil size in another person are indeed encoded into memory and influence judgments of that individual at a later time. Furthermore, these judgments interact with the perceived trustworthiness of the individual and the nature of the social context. The effect is somewhat variable, however, possibly reflecting individual differences and the inherent ambiguity of pupil dilation/constriction. © 2016 The British Psychological Society.

NDT inspections exploiting invariances on scale transformations

NASA Astrophysics Data System (ADS)

Ramos, Helena Geirinhas; Torres, João; Ribeiro, Artur L.; Rebello, João

2015-03-01

The aim of this paper is to show the invariance on the giant magneto-resistor sensor (GMR) output response in the measurement of different plate thicknesses when the problem is resized. To resize the problem, two different probes were projected, implemented and tested: one, with all the dimensions resized by four times the other. Both probes include a pancake coil for magnetic field sinusoidal excitation and measurements are taken with a sensitive bridge fabricated from four giant magneto-resistors (GMR). It is demonstrated, experimentally and with numerical simulation, that the same response value is obtained for two diferent plate thicknesses if dilation principle is kept in the probe's dimensions and electrical quantities. The paper uses the dilation principle to show the invariance of the magnetic field measured by a similar magnetic sensors when data is acquired with the bigger probe on a plate with a thickness four times of the plate thickness used with the smaller probe.

Exploring full cervical dilatation caesarean sections-A retrospective cohort study.

PubMed

Corry, Edward M A; Ramphul, Meenakshi; Rowan, Ann M; Segurado, Ricardo; Mahony, Rhona M; Keane, Declan P

2018-05-01

The rate of caesarean sections at full cervical dilatation with their high risk of morbidity continues to rise mirroring the overall increase in caesarean section rates internationally. The objectives of this study were to determine the rate of full dilatation caesarean section in a tertiary referral unit and evaluate key labour, maternal and fetal factors potentially linked to those deliveries. We also assessed maternal and fetal morbidity at full dilatation sections. Where possible, these were compared with successful operative vaginal deliveries carried out in theatre to determine key differences. Retrospective cohort study. We reviewed the rate of full dilatation caesarean section over a 10-year period. We analysed deliveries (caesarean sections or operative vaginal deliveries) in single cephalic pregnancies ≥34 weeks with contemporaneously collected data from our unit's electronic database for 2015. The rate of full dilatation caesarean section increased by over a third in the ten-year period (56/6947 (0.80%) vs 92/7378 (1.24%), p = 0.01). Of 84 full dilatation caesarean sections who met the inclusion criteria, 63 (75%) were nulliparous and the mean maternal age was 33 (±5) years. Oxytocin was used in the second stage in less than half of second stage caesarean sections (22 out of a recorded 57, 38.6%). There were more fetal head malposition (occipito-posterior, or occipito-transverse) at full dilatation caesarean section compared to successful operative vaginal deliveries (41/46 (89.1%) vs 2/21 (9.5), p < 0.001). The rate of significant postpartum haemorrhage (defined as estimated blood loss ≥1000 ml) was similar in both full dilatation caesarean section and operative vaginal deliveries. There was no difference in the mean birthweight at full dilatation caesarean sections compared to operative vaginal delivery (3.88 kg (2.80-5.33 kg) vs 3.48 kg (1.53-4.40 kg)). There was no difference in neonatal morbidity. Fetal head malposition is associated with a higher risk of full dilatation caesarean section. Interestingly, maternal and fetal morbidity were similar between full dilatation caesarean sections and anticipated difficult operative vaginal deliveries carried out in theatre. The management of labour in terms of the decision to use oxytocin judiciously in hope of correcting inefficient uterine contractions and continuous labour ward training, particularly the diagnosis of malposition and its correction may be beneficial in reducing the rate of full dilation caesarean sections. Copyright © 2018 Elsevier B.V. All rights reserved.

Office Dilation of the Female Urethra: A Quality of Care Problem in the Field of Urology

PubMed Central

Santucci, Richard A.; Payne, Christopher K.; Saigal, Christopher S.

2008-01-01

Purpose: Historically dilation of the female urethra was thought to be of value in the treatment of a variety of lower urinary tract symptoms. Subsequent work has more accurately classified these complaints as parts of various diseases or syndromes in which scant data exist to support the use of dilation. Yet Medicare reimbursement for urethral dilation remains generous and we describe practice patterns regarding female urethral dilation to characterize a potential quality of care issue. Materials and Methods: Health care use by females treated with urethral dilation was compiled using a complementary set of databases. Data sets were examined for relevant inpatient, outpatient and emergency room services for women of all ages. Results: Female urethral dilation is common (929 per 100,000 patients) and is performed almost as much as treatment for male urethral stricture disease. Approximately 12% of these patients are subjected to costly studies such as retrograde urethrography. The overall national costs for treatment exceed $61 million per year and have increased 10% to 17% a year since 1994. A diagnosis of female urethral stricture increases health care expenditures by more than $1,800 per individual per year in insured populations. Conclusions: Urethral dilation is still common despite the fact that true female urethral stricture is an uncommon entity. This scenario is likely secondary to the persistence of the mostly discarded practice of dilating the unstrictured female urethra for a wide variety of complaints despite the lack of data suggesting that it improves lower urinary tract symptoms. PMID:18804232

Fetal stomach paracentesis in combined duodenal and esophageal atresia.

PubMed

Kadohira, Ikuko; Miyakoshi, Kei; Shimojima, Naoki; Matsumoto, Tadashi; Minegishi, Kazuhiro; Tanaka, Mamoru; Kuroda, Tatsuo; Yoshimura, Yasunori

2014-07-01

Fetuses with concomitant duodenal atresia (DA) and esophageal atresia (EA) might develop in utero gastric rupture as well as neonatal respiratory complication due to dilated stomach and duodenum. Our patient with the typical "double bubble" appearance was highly suspected to have DA in the second trimester. Follow-up examinations revealed a massively dilated stomach and duodenum with a dilated distal esophagus, indicating concomitant DA and EA. With advancing pregnancy, the fetal abdomen progressively increased in size by retention of fluid in the closed loop of DA and EA. To avoid gastric perforation, prenatal stomach paracentesis using an ultrasound-guided needle was performed three times until delivery. A male neonate born at 37 weeks gestation showed no respiratory complication. Perinatal clinical features and operative findings revealed combined DA and EA (gross type A). He was successfully managed with duodenoduodenostomy, followed by esophago-esophagostomy. On fetal sonography, the marked "double bubble" appearance and the cystic structure presenting peristalsis-like movement above the diaphragm were indicative of concomitant DA and EA. Fetal stomach paracentesis could contribute to the improvement of perinatal outcomes in fetuses with this pathological condition.

Risk factors associated with short-term outcome and development of perioperative complications in dogs undergoing surgery because of gastric dilatation-volvulus: 166 cases (1992-2003).

PubMed

Beck, Jennifer J; Staatz, Andrew J; Pelsue, Davyd H; Kudnig, Simon T; MacPhail, Catriona M; Seim, Howard B; Monnet, Eric

2006-12-15

To evaluate risk factors associated with death and development of perioperative complications in dogs undergoing surgery for treatment of gastric dilatation-volvulus (GDV). Retrospective case series. 166 dogs. Records of dogs with confirmed GDV that underwent surgery were reviewed. Logistic regression was performed to identify factors associated with development of complications (ie, hypotension, arrhythmias, gastric necrosis necessitating gastrectomy, disseminated intravascular coagulation, peritonitis, sepsis, postoperative dilatation, postoperative vomiting, and incisional problems) and with short-term outcome (ie, died vs survived to the time of suture removal). Short-term mortality rate was 16.2% (27/166). Risk factors significantly associated with death prior to suture removal were clinical signs for > 6 hours prior to examination, combined splenectomy and partial gastrectomy, hypotension at any time during hospitalization, peritonitis, sepsis, and disseminated intravascular coagulation. Partial gastrectomy was not a significant risk factor for death but was for peritonitis, disseminated intravascular coagulation, sepsis, and arrhythmias. Age, gastrectomy, and disseminated intravascular coagulation were risk factors for development of hypotension. Use of a synthetic colloid or hypertonic saline solution was associated with a significantly decreased risk of hypotension. Results suggest that the prognosis for dogs undergoing surgery because of GDV is good but that certain factors are associated with an increased risk that dogs will develop perioperative complications or die.

Impairment of Coronary Arteriolar Endothelium-Dependent Dilation after Multi-Walled Carbon Nanotube Inhalation: A Time-Course Study

PubMed Central

Stapleton, Phoebe A.; Minarchick, Valerie C.; Cumpston, Amy M.; McKinney, Walter; Chen, Bean T.; Sager, Tina M.; Frazer, David G.; Mercer, Robert R.; Scabilloni, James; Andrew, Michael E.; Castranova, Vincent; Nurkiewicz, Timothy R.

2012-01-01

Engineered nanomaterials have been developed for widespread applications due to many highly unique and desirable characteristics. The purpose of this study was to assess pulmonary inflammation and subepicardial arteriolar reactivity in response to multi-walled carbon nanotube (MWCNT) inhalation and evaluate the time course of vascular alterations. Rats were exposed to MWCNT aerosols producing pulmonary deposition. Pulmonary inflammation via bronchoalveolar lavage and MWCNT translocation from the lungs to systemic organs was evident 24 h post-inhalation. Coronary arterioles were evaluated 24–168 h post-exposure to determine microvascular response to changes in transmural pressure, endothelium-dependent and -independent reactivity. Myogenic responsiveness, vascular smooth muscle reactivity to nitric oxide, and α-adrenergic responses all remained intact. However, a severe impact on endothelium-dependent dilation was observed within 24 h after MWCNT inhalation, a condition which improved, but did not fully return to control after 168 h. In conclusion, results indicate that MWCNT inhalation not only leads to pulmonary inflammation and cytotoxicity at low lung burdens, but also a low level of particle translocation to systemic organs. MWCNT inhalation also leads to impairments of endothelium-dependent dilation in the coronary microcirculation within 24 h, a condition which does not fully dissipate within 168 h. The innovations within the field of nanotechnology, while exciting and novel, can only reach their full potential if toxicity is first properly assessed. PMID:23203034

Sympathetic influence on the pupillary light response in three red-eared slider turtles (Trachemys scripta elegans).

PubMed

Dearworth, James R; Cooper, Lori J

2008-01-01

We investigated the effects of phenylephrine and its combination with vecuronium bromide on the iris of turtles to determine if the pupillary light response is affected by sympathetic innervation. Three red-eared slider turtles, Trachemys scripta elegans. Diameters of light-adapted pupils were tracked before and after topical application of drugs to eyes. Phenylephrine was applied independently; in a second group of trials, vecuronium bromide was applied with phenylephrine. Rates of pupil dilation in response to drugs were quantified by fitting data with time constant (tau) equations. Phenylephrine dilated the pupil 24%, tau = 29 min. Combination of phenylephrine with vecuronium bromide increased the pupil size 35%, and dilation was more rapid, tau = 14 min. We also were able to predict these time constants by performing different mathematical operations with an equation developed from a prior study using only vecuronium bromide. When this equation was subtracted from the equation for eyes treated with both vecuronium bromide and phenylephrine, the difference gave the observed tau for phenylephrine; when added to phenylephrine, the sum closely matched the tau for eyes treated with vecuronium bromide and phenylephrine. Further, the tau for vecuronium bromide treated eyes was predicted by subtracting the equation for phenylephrine from that of eyes treated with both vecuronium bromide and phenylephrine. Our results suggest that sympathetic innervation interacts with the parasympathetic pathway to control the pupillary light response in turtles.

Influence of pregnancy and smoking on brachial artery flow-mediated dilation values and time until maximum response.

PubMed

Nicolau, Luis G C; Martins, Wellington P; Gallarreta, Francisco M P; Lima, Jailson C; Filho, Francisco Mauad

2011-08-01

To evaluate the effect of pregnancy and smoking on endothelial function using brachial artery flow-mediated dilation (FMD) and to determine the time necessary until the occurrence of maximum brachial artery dilation after stimulus. This study was an observational study evaluating 133 women, who were grouped as follows: non-smoking pregnant women (N = 47), smoking pregnant women (N = 33), non-smoking women (N = 34), and smoking pregnant women (N = 19). The diameter of the brachial artery was measured at baseline and at 30, 60, 90 and 120 s after stimulus. The relative change of brachial artery was determined for each of these four moments. FMD measured at 60 s after stimulus was compared between the groups. The maximum FMD was observed at 60 s after cuff release in all groups. FMD was greater among non-smoking pregnant women compared to smoking pregnant women (11.50 ± 5.77 vs. 8.74 ± 4.83; p = 0.03) and also between non-smoking non-pregnant women compared to smoking non-pregnant women (10.52 ± 4.76 vs. 7.21 ± 5.57; p = 0.03). Maximum FMD was observed approximately 60 s after stimulus in all groups regardless of smoking and pregnancy status. The smoking habit seems to lead to endothelial dysfunction both in pregnant and non-pregnant women, as demonstrated by the lower FMD in smokers.

The procedure of mesh wrapping the gastric pouch in cadaver study.

PubMed

Gong, Ke; Gagner, Michel; Bardaro, Sergio; Ueda, Kazuki

2007-12-01

Dietary and behavioral modifications have resulted in limited long-term success in curing morbidly obese patients, and surgery remains the only effective treatment. Of the surgical procedures that are the most commonly offered, Roux-en-Y gastric bypass (RYGB) appears to offer the best long-term results. However 5-15% of patients will not achieve successful weight loss after RYGB. There are many reports showing that the patients who underwent gastric bypass surgeries regain weight over time. The cause for this remains unclear. Several factors may contribute, including dilation of the gastric pouch and the gastrojejunal anastomosis. However, the data to support the link is sparse. The objective of this paper is to describe the surgical technique of wrapping the gastric pouch with a polytetrafluoroethylene (PTFE) mesh to prevent gastric pouch dilatation. In specific, we created a 20-30 ml gastric pouch and subsequently, the gastrojejunostomy was performed with a circular stapler. Afterwards, the mesentery was dissected and the gastric pouch was wrapped with the PTFE mesh. We have performed this procedure on three cadavers with an average operative time of 75 minutes. We found that the procedure of wrapping the gastric pouch was not particularly difficult. As a result, the gastric pouch, gastrojejunal anastomosis and the stump of the jejunum are all totally wrapped within the mesh. It may be effective in the prevention of dilatation.

A novel technique of concurrent esophagoscopy and transgastrostomy gastroscopy to dilate a completely obstructed distal esophageal stricture in a child following fundoplication.

PubMed

Isaiah, J H; Jones, A B; Lalor, E; Evans, M; Dhunno, I; Huynh, H Q

2005-08-01

We report a successful dilation of a completely obstructed distal esophageal stricture in a 4-year-old boy with combined immune deficiency syndrome, at 2 and half years after fundoplication and gastrostomy tube insertion. Barium studies and esophagoscopy had revealed complete obstruction of the lower esophagus. Transgastrostomy gastroscopy demonstrated a pinhole lumen through the fundoplication wrap; a guide wire was passed into the esophagus; and the stricture was dilated with Savary dilators. We presumed that the stricture was secondary to chronic esophagitis. The stricture was identified and successfully dilated using a novel technique of concurrent esophagoscopy and transgastrostomy gastroscopy.

Aortic dilatation in Turner syndrome: the role of MRI in early recognition.

PubMed

Chalard, François; Ferey, Solène; Teinturier, Cécile; Kalifa, Gabriel

2005-03-01

Aortic dilatation and dissection are rare but important complications of Turner syndrome that increase the risk of sudden death in young patients. To assess the value of aortic MRI in patients with Turner syndrome; in particular to demonstrate early aortic dilatation. A total of 21 patients with Turner syndrome underwent MRI of the thoracic aorta with measurement of vessel diameter at four levels. Measurements were normal for age in 15 cases, two patients presented with values at the upper limit of normal and four had obvious dilatation of the ascending aorta. All were symptom free. MRI allows the non-invasive demonstration of early aortic dilatation, which may lead to earlier surgery in asymptomatic individuals.

Novel use of tissue expander for dilation of oropharyngeal stenosis.

PubMed

Banerjee, Debdeep; Wang, James C; Demke, Joshua C

2014-11-01

Naso/oropharyngeal stenoses are uncommon surgical complications. We present a child having undergone previous adenoidectomy without complication who developed naso/oropharyngeal scarring after subsequent tonsillectomy. She presented with nasal obstruction and frequent gasping at night worrisome for obstructive sleep apnea. Scar was initially excised and the defect allografted. Conventional esophageal dilators were undersized, and ultimately a tissue expander was used intraoperatively as a balloon dilator. The patient's symptoms and sleep apnea resolved. We found use of a tissue expander as a balloon dilator to be at least minimally effective in dilating the oropharynx when all other methods at our disposal proved ineffective. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Duodenal adenocarcinoma presenting as a mass with aneurismal dilatation.

PubMed

Mama, Nadia; Ben Slama, Aïda; Arifa, Nadia; Kadri, Khaled; Sriha, Badreddine; Ksiaa, Mehdi; Jemni, Hela; Tlili-Graiess, Kalthoum

2014-01-01

Duodenal adenocarcinoma is frequent. Aneurysmal dilatation of the small bowel is reported to be a lymphoma characteristic imaging finding. A 57-year-old male was found to have a duodenal adenocarcinoma with aneurismal dilatation on imaging which is an exceptional feature. On laparotomy, the wall thickening of the dilated duodenum extended to the first jejunal loop, with multiple mesenteric lymph nodes and ascites. Segmental palliative resection with gastro-entero-anastomosis was done. Histopathology revealed a moderately differentiated adenocarcinoma with neuro-endocrine differentiation foci. Wide areas of necrosis and vascular emboli were responsible for the radiological feature of the dilated duodenum with wall thickening. Copyright © 2014 Elsevier Inc. All rights reserved.

Detecting of foreign object debris on airfield pavement using convolution neural network

NASA Astrophysics Data System (ADS)

Cao, Xiaoguang; Gu, Yufeng; Bai, Xiangzhi

2017-11-01

It is of great practical significance to detect foreign object debris (FOD) timely and accurately on the airfield pavement, because the FOD is a fatal threaten for runway safety in airport. In this paper, a new FOD detection framework based on Single Shot MultiBox Detector (SSD) is proposed. Two strategies include making the detection network lighter and using dilated convolution, which are proposed to better solve the FOD detection problem. The advantages mainly include: (i) the network structure becomes lighter to speed up detection task and enhance detection accuracy; (ii) dilated convolution is applied in network structure to handle smaller FOD. Thus, we get a faster and more accurate detection system.

Dilation of the olfactory bulb cavity concurrent with hydrocephalus in four small breed dogs

PubMed Central

Kim, Jung-Hyun; Jeon, Hyo-Won; Woo, Eung-Je

2009-01-01

Four small breed dogs were admitted with seizures. Magnetic resonance imaging (MRI) of the brain revealed dilation of the olfactory bulb cavity as well as enlargement of the lateral ventricles. These findings demonstrate that dilation of the olfactory bulb cavity can occur concurrent with hydrocephalus. This is the first description of the clinical and MRI features of dilation of the olfactory bulb cavity concurrent with hydrocephalus in dogs. PMID:19461216

Dilated cardiomyopathy and sinoatrial dysfunction in an Estrela mountain dog.

PubMed

Lobo, Luis; Pinheiro-Vieira, António; Gomes, João L; Canada, Nuno; Ribeiro, Lenio; Costa, Paulo D; Oliveira, Pedro; Bussadori, Claudio

2012-01-01

A 1 yr old male Estrela mountain dog was evaluated as a part of a screening program for dilated cardiomyopathy. The dog came from a family with a history of dilated cardiomyopathy but was asymptomatic. Occult dilated cardiomyopathy and sino-atrial dysfunction were diagnosed based on echocardiography and electrocardiography. These two disorders may be associated given that related dogs have been diagnosed with the same disorders. The dog has remained asymptomatic for 4 years following initial evaluation.

Muscles involved in naris dilation and nose motion in rat

PubMed Central

Deschênes, Martin; Haidarliu, Sebastian; Demers, Maxime; Moore, Jeffrey; Kleinfeld, David; Ahissar, Ehud

2016-01-01

In a number of mammals muscle dilator nasi (naris) is known as a muscle that reduces nasal airflow resistance by dilating the nostrils. Here we show that in rats the tendon of this muscle inserts into the aponeurosis above the nasal cartilage. Electrical stimulation of this muscle lifts the nose and deflects it sideway towards the side of stimulation, but does not change the size of the nares. In the head-fixed alert rat, electromyographic activity of muscle dilator nasi is tightly coupled to nose motion, not to opening of the nares. Yet, contraction of muscle dilator nasi occurs during the pre-inspiratory phase of the respiratory cycle, suggesting a role in sniffing and sampling odorants. We also show that opening of the nares results from contraction of pars maxillaris profunda of the muscle nasolabialis profundus. This muscle attaches to the outer wall of the nasal cartilage and to the plate of the mystacial pad. Contraction of this muscle exerts a dual action: it pulls the lateral nasal cartilage outwardly, thus dilating the naris, and it drags the plate of the mystacial pad rostralward, provoking a slight retraction of the whiskers. On the basis of these results, we propose that muscle dilator nasi of the rat be renamed muscle deflector nasi, and that pars maxillaris profunda of the muscle nasolabialis profundus be named muscle dilator nasi. PMID:25257748

The induction of nitric oxide-mediated relaxation of human isolated pulmonary arteries by PACAP

PubMed Central

Cardell, Lars Olaf; Hjert, Ola; Uddman, Rolf

1997-01-01

The effects of pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP) were analysed in human isolated circular segments of pulmonary arteries. Guinea-pig pulmonary arteries were used for comparison. The responses obtained were analysed in relation to the vascular endothelium and the nitric oxide (NO) synthase inhibitor NG-monomethyl L-arginine (L-NMMA).PACAP and VIP induced concentration-dependent relaxations of precontracted pulmonary arteries. The maximal dilator response (Imax,%) and the potency (pEC50 value) were the same for both peptides, and there were no differences in the effects obtained on human and guinea-pig segments. PACAP and VIP were both more potent that acetylcholine (ACh).Removal of the vascular endothelium abolished the PACAP induced dilator response in pulmonary arteries from both species. The VIP induced dilatation was unaffected, whereas the response to ACh was abolished. L-NMMA given before PACAP inhibited the dilatation. Furthermore, L-NMMA also reversed the dilatation already induced by PACAP and excess concentrations of L-arginine restored the dilator response of the L-NMMA treated arteries.PACAP is a potent dilator of human pulmonary arteries. Although the dilator effect seems to be similar in amplitude to the one induced by VIP, the present results suggest differences in the underlying mechanisms of action (endothelium-dependency) between the two peptides. PMID:9134222

Is It Possible to Increase Flap Viability by Hydrostatic Dilation?: An Experimental Study in the Rat Abdominal Fasciocutaneous Flap Model.

PubMed

Sahin, Cihan; Aysal, Bilge Kagan; Ergun, Ozge

2016-08-01

Ergun et al previously demonstrated the efficacy of hydrostatic dilation in a TRAM flap model in an experimental study. We investigated the effect of hydrostatic dilation on a fasciocutaneous flap model. Eighteen female Wistar rats were equally divided into 3 groups, of which 1 served as a control. In the second, the abdominal fasciocutaneous flap surgical delay procedure was performed by division of the left superficial inferior epigastric (SIE) vessels. In the third, hydrostatic dilation was performed on the left SIE artery and vein, with a mean pressure of 300 mm Hg, while elevating the flap on the right-sided SIE pedicle. The groups were compared by microangiography and by the survival ratio of abdominal flaps 7 days after elevation. The mean (SD) flap necrosis rates were as follows: control group, 44.75% (4.31%); delay group, 33.32% (7.11%); and hydrostatic dilation group, 32.51% (5.03%). There was a significant difference between the control group and the other 2 groups (P < 0.05). There was no difference between the delay and hydrostatic dilation groups with respect to surface area necrosis. The microangiographies showed remarkable increased vascularity in the delay and hydrostatic dilation groups. Hydrostatic dilation is a new method of enhancing flap viability that could be used in clinical cases in place of surgical delay once further studies and clinical trials are completed.

Effect of acute gastric dilatation on gastric myoelectic and motor activity in dogs.

PubMed

Hall, J A; Solie, T N; Seim, H B; Twedt, D C

1999-05-01

To investigate the effects of experimentally induced acute gastric dilatation on electrical and mechanical activities of the stomach in dogs. 7 healthy dogs. Electrodes and strain-gauge force transducers were implanted on the serosal surface of the antrum and pylorus. Eight days later, baseline gastric electrical and contractile activities were recorded. The dogs were anesthetized and mechanically ventilated to maintain normocapnia while the stomach was distended (intragastric pressure, 30 mm Hg) for 180 minutes, using a thin compliant bag. Gastric electrical and contractile activities were recorded again on days 1 and 10 after dilatation. Recordings were analyzed to determine gastric slow-wave frequency, slow-wave dysrhythmia, propagation velocity of slow-waves, coupling of contractions to slow waves, motility index on the basis of relative contractile amplitudes, and onset of contractions after a standardized meal. Electrical or contractile activities were not significantly different 18 hours after acute gastric dilatation (day 1). Arrhythmias were evident before and after gastric dilatation in dogs from which food was withheld and in dogs after consumption of a meal. Variables for assessing gastric electrical and contractile activities were unaffected 18 hours after acute gastric dilatation. Analysis of results of this study indicated that altered electrical and contractile activities in dogs with short-term gastric dilatation are not likely to be secondary to the process of acute gastric dilatation.

The Esophageal Anastomotic Stricture Index (EASI) for the management of esophageal atresia.

PubMed

Sun, Linda Yi-Chan; Laberge, Jean-Martin; Yousef, Yasmine; Baird, Robert

2015-01-01

Anastomotic stricture is the most common complication following repair of esophageal atresia. An Esophageal Anastomotic Stricture Index (EASI) based on the postoperative esophagram may identify patients at high risk of stricture formation. Digital images of early postoperative esophagrams of patients undergoing EA repair from 2005 to 2013 were assessed. Demographics and outcomes including dilations were prospectively collected. Upper (U-EASI) and lower (L-EASI) pouch ratios were generated using stricture diameter divided by maximal respective pouch diameter. Score performances were evaluated with area under the receiver operator curves (AUC) and the Fisher's exact test for single and multiple (>3) dilatations. Interrater agreement was evaluated using the intraclass correlation coefficient (ICC). Forty-five patients had esophagrams analyzed; 28 (62%) required dilatation and 19 received >3 (42%). U-EASI and L-EASI ratios ranged from 0.17 to 0.70, with L-EASI outperforming the U-EASI as follows: L-EASI AUC: 0.66 for a single dilatation, 0.65 for >3 dilatations; U-EASI AUC: 0.56 for a single dilatation, 0.67 for >3 dilatations. All patients with an L-EASI ratio of ≤0.30 (n=8) required multiple esophageal dilatations, p=0.0006. The interrater ICC was 0.87. The EASI is a simple, reproducible tool to predict the development and severity of anastomotic stricture after esophageal atresia repair and can direct postoperative surveillance. Copyright © 2015 Elsevier Inc. All rights reserved.

Constraining friction, dilatancy and effective stress with earthquake rates in the deep crust

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Thomas, A.; Burgmann, R.; Shelly, D. R.

2015-12-01

Similar to their behavior on the deep extent of some subduction zones, families of recurring low-frequency earthquakes (LFE) within zones of non-volcanic tremor on the San Andreas fault in central California show strong sensitivity to stresses induced by the tides. Taking all of the LFE families collectively, LFEs occur at all levels of the daily tidal stress, and are in phase with the very small, ~200 Pa, shear stress amplitudes while being uncorrelated with the ~2 kPa tidal normal stresses. Following previous work we assume LFE sources are small, persistent regions that repeatedly fail during shear within a much larger scale, otherwise aseismically creeping fault zone and that the correlation of LFE occurrence reflects modulation of the fault creep rate by the tidal stresses. We examine the predictions of laboratory-observed rate-dependent dilatancy associated with frictional slip. The effect of dilatancy hardening is to damp the slip rate, so high dilatancy under undrained pore pressure reduces modulation of slip rate by the tides. The undrained end-member model produces: 1) no sensitivity to the tidal normal stress, as first suggested in this context by Hawthorne and Rubin [2010], and 2) fault creep rate in phase with the tidal shear stress. Room temperature laboratory-observed values of the dilatancy and friction coefficients for talc, an extremely weak and weakly dilatant material, under-predict the observed San Andreas modulation at least by an order of magnitude owing to too much dilatancy. This may reflect a temperature dependence of the dilatancy and friction coefficients, both of which are expected to be zero at the brittle-ductile transition. The observed tidal modulation constrains the product of the friction and dilatancy coefficients to be at most 5 x 10-7 in the LFE source region, an order of magnitude smaller than observed at room temperature for talc. Alternatively, considering the predictions of a purely rate-dependent talc friction would constrain the ambient effective normal stress to be no more than 40 kPa. In summary, for friction models that have both rate-dependent strength and dilatancy, the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid pressures.

Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects of sleep deprivation in healthy individuals.

PubMed

Grassi, Davide; Socci, Valentina; Tempesta, Daniela; Ferri, Claudio; De Gennaro, Luigi; Desideri, Giovambattista; Ferrara, Michele

2016-07-01

Sleep deprivation is a risk factor for cardiovascular disease. Cocoa flavonoids exert cardiovascular benefits and neuroprotection. Whether chocolate consumption may mitigate detrimental effects of sleep loss on cognitive performance and cardiovascular parameters has never been studied. We investigated the effects of flavanol-rich chocolate consumption on cognitive skills and cardiovascular parameters after sleep deprivation. Thirty-two healthy participants underwent two baseline sessions after one night of undisturbed sleep and two experimental sessions after one night of total sleep deprivation. Two hours before each testing session, participants were randomly assigned to consume high or poor flavanol chocolate bars. During the tests were evaluated, the Psychomotor Vigilance Task and a working memory task, office SBP and DBP, flow-mediated dilation and pulse-wave velocity. Sleep deprivation increased SBP/DBP. SBP/DBP and pulse pressure were lower after flavanol-rich treatment respect to flavanol-poor treatment (SBP: 116.9 ± 1.6 vs. 120.8 ± 1.9 mmHg, respectively, P = 0.00005; DBP: 70.5 ± 1.2 vs. 72.3 ± 1.2 mmHg, respectively, P = 0.01; pulse pressure: 46.4 ± 1.3 vs. 48.4 ± 1.5 mmHg, P = 0.004). Sleep deprivation impaired flow-mediated dilation (5.5 ± 0.5 vs. 6.5 ± 0.6%, P = 0.02), flavanol-rich, but not flavanol-poor chocolate counteracted this alteration (flavanol-rich/flavanol-poor chocolate: 7.0 ± 0.6 vs. 5.0 ± 0.4%, P = 0.000001). Flavanol-rich chocolate mitigated the pulse-wave velocity increase (P = 0.001). Flavanol-rich chocolate preserved working memory accuracy in women after sleep deprivation. Flow-mediated dilation correlated with working memory performance accuracy in the sleep condition (P = 0.04). Flavanol-rich chocolate counteracted vascular impairment after sleep deprivation and restored working memory performance. Improvement in cognitive performance could be because of the effects of cocoa flavonoids on blood pressure and peripheral and central blood flow.

Salivary gland enlargement during oesophageal stricture dilatation.

PubMed Central

Martin, D.

1980-01-01

A case of recurrent salivary gland enlargement occurring during fibreoptic oesophagoscopy and oesophageal stricture dilatation with Eder-Puestow dilators is described. The genesis of this condition is discussed and its transient and usually benign nature emphasized. Images Fig. 1 PMID:7393809

Perception while watching movies: Effects of physical screen size and scene type

PubMed Central

Troscianko, Tom; Meese, Timothy S.; Hinde, Stephen

2012-01-01

Over the last decade, television screens and display monitors have increased in size considerably, but has this improved our televisual experience? Our working hypothesis was that the audiences adopt a general strategy that “bigger is better.” However, as our visual perceptions do not tap directly into basic retinal image properties such as retinal image size (C. A. Burbeck, 1987), we wondered whether object size itself might be an important factor. To test this, we needed a task that would tap into the subjective experiences of participants watching a movie on different-sized displays with the same retinal subtense. Our participants used a line bisection task to self-report their level of “presence” (i.e., their involvement with the movie) at several target locations that were probed in a 45-min section of the movie “The Good, The Bad, and The Ugly.” Measures of pupil dilation and reaction time to the probes were also obtained. In Experiment 1, we found that subjective ratings of presence increased with physical screen size, supporting our hypothesis. Face scenes also produced higher presence scores than landscape scenes for both screen sizes. In Experiment 2, reaction time and pupil dilation results showed the same trends as the presence ratings and pupil dilation correlated with presence ratings, providing some validation of the method. Overall, the results suggest that real-time measures of subjective presence might be a valuable tool for measuring audience experience for different types of (i) display and (ii) audiovisual material. PMID:23145293

Evidence of ventricular contamination of the optical signal in preterm neonates with post hemorrhagic ventricle dilation

NASA Astrophysics Data System (ADS)

Kishimoto, J.; Diop, M.; McLachlan, P.; de Ribaupierre, S.; Lee, D. S. C.; St. Lawrence, K.

2015-03-01

Dilation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). This post hemorrhagic ventricle dilation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure (ICP). Interventions, such as ventricular tapping to remove cerebrospinal fluid (CSF), are used to prevent injury, but determining the optimal time for treatment is difficult as clinical signs of increased ICP lack sensitivity. There is a growing interest in using near-infrared spectroscopy (NIRS) because of its ability to monitor cerebral oxygen saturation (StO2) at the bedside. However, the accuracy of NIRS may be affected by signal contamination from enlarged ventricles, especially if there are blood breakdown products (bbp) in CSF following IVH. To investigate this, serial NIR spectra from the head and from CSF samples were acquired over a month from seven IVH patients undergoing treatment for PHVD. Over time, the visual appearance of the CSF samples progressed from dark brown ("tea color") to clear yellow, reflecting the reduction in bbp concentration as confirmed by the stronger absorption around 760 nm at the earlier time points. All CSF samples contained strong absorption at 960 nm due to water. More importantly the same trend in these absorption features was observed in the in vivo spectra, and Monte Carlo simulations confirmed the potential for signal contamination from enlarged ventricles. These findings highlight the challenges of accurately measuring StO2 in this patient population and the necessity of using a hyperspectral NIRS system to resolve the additional chromophores.

Subject-specific left ventricular dysfunction modeling using composite material mechanics approach

NASA Astrophysics Data System (ADS)

Haddad, Seyed Mohammad Hassan; Karami, Elham; Samani, Abbas

2017-03-01

Diverse cardiac conditions such as myocardial infarction and hypertension can lead to diastolic dysfunction as a prevalent cardiac condition. Diastolic dysfunctions can be diagnosed through different adverse mechanisms such as abnormal left ventricle (LV) relaxation, filling, and diastolic stiffness. This paper is geared towards evaluating diastolic stiffness and measuring the LV blood pressure non-invasively. Diastolic stiffness is an important parameter which can be exploited for more accurate diagnosis of diastolic dysfunction. For this purpose, a finite element (FE) LV mechanical model, which works based on a novel composite material model of the cardiac tissue, was utilized. Here, this model was tested for inversion-based applications where it was applied for estimating the cardiac tissue passive stiffness mechanical properties as well as diastolic LV blood pressure. To this end, the model was applied to simulate diastolic inflation of the human LV. The start-diastolic LV geometry was obtained from MR image data segmentation of a healthy human volunteer. The obtained LV geometry was discretized into a FE mesh before FE simulation was conducted. The LV tissue stiffness and diastolic LV blood pressure were adjusted through optimization to achieve the best match between the calculated LV geometry and the one obtained from imaging data. The performance of the LV mechanical simulations using the optimal values of tissue stiffness and blood pressure was validated by comparing the geometrical parameters of the dilated LV model as well as the stress and strain distributions through the LV model with available measurements reported on the LV dilation.

[Development and evaluation of a prosthetic valved conduit dilated by percutaneous approach: experimental study in the lamb].

PubMed

Boudjemline, Y; Laborde, F; Pineau, E; Mollet, A; Abadir, S; Bonhoeffer, P; Bonnet, D; Sidi, D

2006-05-01

This study was undertaken to develop a dilated valved conduit for reconstruction of the right ventricular outflow tract in the animal. The conduits were made by sewing a valved tube (Medtronic Inc) inside a vascular stent (Numed Inc). After preparation, they were inserted surgically in five lambs. The conduits were then dilated 6 weeks and 3 months after their implantation. Before sacrificing the animals at 3 months, a 22 mm valved stent was implanted percutaneously inside the surgical conduits. One animal died suddenly due to kinking of the conduit. Balloon dilatation was performed in the surviving animals. The first dilatation only had a modest impact on valvular function but it was much aggravated after the second dilatation. A valved stent was successfully inserted percutaneously. At sacrifice, all the conduits were completely engulfed in an intense fibrosis. In conclusion, a valved biological conduit for reconstruction of the right ventricular ejection tract has been developed and can be dilated sequentially to follow growth. The new product could have an important role to play in the management of congenital malformations involving the right ventricular outflow tract.

Endoscopic minor papilla balloon dilation for the treatment of symptomatic pancreas divisum.

PubMed

Yamamoto, Natsuyo; Isayama, Hiroyuki; Sasahira, Naoki; Tsujino, Takeshi; Nakai, Yousuke; Miyabayashi, Koji; Mizuno, Suguru; Kogure, Hirofumi; Sasaki, Takashi; Hirano, Kenji; Tada, Minoru; Koike, Kazuhiko

2014-08-01

A subpopulation of patients with pancreas divisum experience symptomatic events such as recurrent acute pancreatitis and chronic pancreatitis. Minor papilla sphincterotomy has been reported as being an effective treatment. The aim of this study was to evaluate the safety and efficacy of endoscopic balloon dilation for the minor papilla. Between 2000 and 2012, 16 patients were retrospectively included in this study. After endoscopic balloon dilation for the minor papilla was received, a pancreatic stent or a nasal pancreatic drainage catheter was placed for 1 week. If a stricture or obstruction was evident, it was treated with balloon dilation followed by long-term stent placement (1 year). When an outflow of pancreatic juice was disturbed by a pancreatic stone, endoscopic stone extraction was performed. Balloon dilation and stent placement were achieved and were successful in all the cases (16/16; 100%). Clinical improvement was achieved in 7 (84.7%) of the 9 patients with recurrent acute pancreatitis and in 6 (85.7%) of the 7 patients with chronic pancreatitis. Early complications were observed in 1 (6.3%) patient. Pancreatitis or bleeding related to balloon dilation was not observed. Endoscopic balloon dilation for the minor papilla is feasible for the management of symptomatic pancreas divisum.

Dilatational band formation in bone

PubMed Central

Poundarik, Atharva A.; Diab, Tamim; Sroga, Grazyna E.; Ural, Ani; Boskey, Adele L.; Gundberg, Caren M.; Vashishth, Deepak

2012-01-01

Toughening in hierarchically structured materials like bone arises from the arrangement of constituent material elements and their interactions. Unlike microcracking, which entails micrometer-level separation, there is no known evidence of fracture at the level of bone’s nanostructure. Here, we show that the initiation of fracture occurs in bone at the nanometer scale by dilatational bands. Through fatigue and indentation tests and laser confocal, scanning electron, and atomic force microscopies on human and bovine bone specimens, we established that dilatational bands of the order of 100 nm form as ellipsoidal voids in between fused mineral aggregates and two adjacent proteins, osteocalcin (OC) and osteopontin (OPN). Laser microdissection and ELISA of bone microdamage support our claim that OC and OPN colocalize with dilatational bands. Fracture tests on bones from OC and/or OPN knockout mice (OC−/−, OPN−/−, OC-OPN−/−;−/−) confirm that these two proteins regulate dilatational band formation and bone matrix toughness. On the basis of these observations, we propose molecular deformation and fracture mechanics models, illustrating the role of OC and OPN in dilatational band formation, and predict that the nanometer scale of tissue organization, associated with dilatational bands, affects fracture at higher scales and determines fracture toughness of bone. PMID:23129653

Nasal Dilators (Breathe Right Strips and NoZovent) for Snoring and OSA: A Systematic Review and Meta-Analysis

PubMed Central

Malu, Omojo O.; Kram, Yoseph A.; Song, Sungjin A.; Tolisano, Anthony M.; Kushida, Clete A.

2016-01-01

Objective. To systematically review the international literature for studies evaluating internal (NoZovent) and external (Breathe Right Strips) nasal dilators as treatment for obstructive sleep apnea (OSA). Study Design. Systematic review with meta-analysis. Methods. Four databases, including PubMed/MEDLINE, were searched through September 29, 2016. Results. One-hundred twelve studies were screened, fifty-eight studies were reviewed, and fourteen studies met criteria. In 147 patients, the apnea-hypopnea index (AHI) was reported, and there was an improvement from a mean ± standard deviation (M ± SD) of 28.7 ± 24.0 to 27.4 ± 23.3 events/hr, p value 0.64. There was no significant change in AHI, lowest oxygen saturation, or snoring index in OSA patients when using nasal dilators. However, a subanalysis demonstrated a slight reduction in apnea index (AI) with internal nasal dilators (decrease by 4.87 events/hr) versus minimal change for external nasal dilators (increase by 0.64 events/hr). Conclusion. Although nasal dilators have demonstrated improved nasal breathing, they have not shown improvement in obstructive sleep apnea outcomes, with the exception of mild improvement in apnea index when internal nasal dilators were used. PMID:28070421

Congenital duodenal web: successful management with endoscopic dilatation

PubMed Central

Poddar, Ujjal; Jain, Vikas; Yachha, Surender Kumar; Srivastava, Anshu

2016-01-01

Background and study aims: Congenital duodenal web (CDW) is an uncommon cause of duodenal obstruction and endoscopic balloon dilatation has been reported in just eight pediatric cases to date. Here we are reporting three cases of CDW managed successfully with balloon dilatation. Cases and methods: In 2014 we diagnosed three cases of CDW on the basis of typical radiological and endoscopic findings. Endoscopic balloon dilatation was done under conscious sedation with a through-the-scope controlled radial expansion (CRE) balloon. Results: All three children presented late (median age 8 [range 2 – 9] years) with bilious vomiting, upper abdominal distension, and failure to thrive. One of them had associated Down syndrome and another had horseshoe kidney. In all cases, CDW was observed in the second part of the duodenum beyond the ampulla, causing partial duodenal obstruction. After repeated endoscopic dilatation (2 – 4 sessions), all three patients became asymptomatic. None of the patients experienced complications after balloon dilatation. Conclusions: Duodenal diaphragm should be suspected in patients with abdominal distension with bilious vomiting, even in relatively older children. Endoscopic balloon dilatation is a simple and effective method of treating this condition. PMID:27004237

Using gravity as a proxy for stress accumulation in complex fault systems

NASA Astrophysics Data System (ADS)

Hayes, Tyler Joseph

The gravity signal contains information regarding changes in density at all depths and can be used as a proxy for the strain accumulation in fault networks. A general method for calculating the total, dilatational, and free-air gravity for fault systems with arbitrary geometry, slip motion, and number of fault segments is presented. The technique uses a Green's function approach for a fault buried within an elastic half-space with an underlying driver plate forcing the system. A stress-evolution time-dependent earthquake fault model was used to create simulated slip histories over the San Andreas Fault network in California. Using a sum of the gravity signals from each fault segment in the model, via coseismic gravity Green's functions, a time-dependent gravity model was created. The steady-state gravity from the long term plate motion generates a signal over five years with magnitudes of +/- ˜2 muGal; the current limit of portable instrument observations. Moderate to large events generate signal magnitudes in the range of ˜10 muGal to ˜80 muGal, well within the range of ground based observations. The complex fault network geometry of California significantly affects the spatial extent of the gravity signal from the three events studied. Statistical analysis of 55 000 years of simulated slip histories were used to investigate the use of the dilatational gravity signal as a proxy for precursory stress and strain changes. Results indicate that the precursory dilatational gravity signal is dependent upon the fault orientation with respect the tectonic loading plate velocity. This effect is interpreted as a consequence of preferential amplification of the shear stress or reduction of the normal stress, depending on the steady-state regime investigated. Finally, solutions for the corresponding gravity gradients of the coseismic dilatational gravity signals are developed for a vertical strike-slip fault. Gravity gradient solutions exhibit similar spatial distributions as those calculated for Coulomb stress changes, reflecting their physical relationship to the stress changes. The magnitude of the signals, on the order of 1 x 10-4 E, are beyond the resolution of typical exploration instruments at the present time. Keywords. numerical solutions; seismic cycle; gravity; gravity gradients; time variable gravity; earthquake interaction; forecasting; and prediction

Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys; Kone, El Hadj

2017-04-01

Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [1]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/ dilatation of the granular media and its interaction with the pore fluid pressure [2]. The model is derived from a 3D two-phase model proposed by Jackson [3] and the mixture equations are closed by a weak compressibility relation. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid or a solid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. Interestingly, when removing the role of water, our model reduces to a dry granular flow model including dilatancy. We first compare experimental and numerical results of dilatant dry granular flows. Then, by quantitatively comparing the results of simulation and laboratory experiments on submerged granular flows, we show that our model contains the basic ingredients making it possible to reproduce the interaction between the granular and fluid phases through the change in pore fluid pressure. In particular, we analyse the different time scales in the model and their role in granular/fluid flow dynamics. References [1] R. Delannay, A. Valance, A. Mangeney, O. Roche, P. Richard, J. Phys. D: Appl. Phys., in press (2016). [2] F. Bouchut, E. D. Fernández-Nieto, A. Mangeney, G. Narbona-Reina, J. Fluid Mech., 801, 166-221 (2016). [3] R. Jackson, Cambridges Monographs on Mechanics (2000).

Reproducibility of the retinal vascular response to flicker light in Asians.

PubMed

Nguyen, Thanh T; Kreis, Andreas J; Kawasaki, Ryo; Wang, Jie Jin; Seifert, Bernd-U; Vilser, Walthard; Nagel, Edgar; Wong, Tien Y

2009-12-01

Dilation of retinal vessels in response to diffuse luminance flicker may reflect endothelial function. Although this has previously been shown to be reproducible in whites, there have been no similar data in Asians. We assess the reproducibility of repeated measurements of this response in Asians. Healthy Asians (n = 33) with normal vision and no history of glaucoma, age-related macular degeneration, cataract, or retinal arterial/venous occlusion participated in this study. Repeated measures from the same subjects were taken 30-60 min apart using the Dynamic Vessel Analyser (DVA, IMEDOS, Jena, Germany). Modification was made to the shape of the light source for Asian participants. Correlations of the first and second measures were assessed using Pearson correlation (R(2)), and agreement between the two measures was shown using Bland-Altman plots. After modification to the shape of the light source, almost perfect correlation was found between the 1st and 2nd measurements of baseline arteriolar (R(2) = 0.95) and venular diameters (R(2) = 0.98) of arteriolar maximum dilation (R(2) = 0.85). Substantially high correlation between the 1st and 2nd measurements of venular maximum dilation was found (R(2) = 0.80). Measurements of the dilation response of retinal vessels to diffuse luminance flicker an Asian sample using the DVA show high reproducibility for repeated measures over a short period of time. Such measurements may allow non-invasive quantification of endothelial function to study its association with systemic and ocular diseases.

Elastin-derived peptides promote abdominal aortic aneurysm formation by modulating M1/M2 macrophage polarization1

PubMed Central

Dale, Matthew A; Xiong, Wanfen; Carson, Jeffrey S; Suh, Melissa K; Karpisek, Andrew D.; Meisinger, Trevor M.; Casale, George P.; Baxter, B. Timothy

2016-01-01

Abdominal aortic aneurysm (AAA) is a dynamic vascular disease characterized by inflammatory cell invasion and extracellular matrix (ECM) degradation. Damage to elastin in the ECM results in release of elastin-derived peptides (EDPs), which are chemotactic for inflammatory cells such as monocytes. Their effect on macrophage polarization is less well known. Pro-inflammatory M1 macrophages initially are recruited to sites of injury but, if their effects are prolonged, they can lead to chronic inflammation that prevents normal tissue repair. Conversely, anti-inflammatory M2 macrophages reduce inflammation and aid in wound healing. Thus, a proper M1/M2 ratio is vital for tissue homeostasis. AAA tissue reveals a high M1/M2 ratio where pro-inflammatory cells and their associated markers dominate. In the present study, in vitro treatment of bone marrow-derived macrophages with EDPs induced M1 macrophage polarization. By using C57Bl/6 mice, antibody-mediated neutralization of EDPs reduced aortic dilation, matrix metalloproteinase activity, and pro-inflammatory cytokine expression at early and late time points after aneurysm induction. Furthermore, direct manipulation of the M1/M2 balance altered aortic dilation. Injection of M2 polarized macrophages reduced aortic dilation after aneurysm induction. EDPs promoted a pro-inflammatory environment in aortic tissue by inducing M1 polarization and neutralization of EDPs attenuated aortic dilation. The M1/M2 imbalance is vital to aneurysm formation. PMID:27183603

Doppler ultrasound-guided percutaneous nephrolithotomy with two-step tract dilation for management of complex renal stones.

PubMed

Xu, Youming; Wu, Zhonghua; Yu, Jianhua; Wang, Shulong; Li, Fang; Chen, Jiushun; Liu, Jin; Chen, Kan

2012-06-01

To report our experience and assess the safety and efficacy of Doppler ultrasound-guided percutaneous nephrolithotomy (PCNL) with 2-step tract dilation for complex renal stones. From March 2009 to February 2011, 262 patients underwent PCNL. Eighty-three patients had a complete and 105 had partial staghorn calculus, and 74 had a renal pelvic stone of >2 cm in diameter. Thirty-five patients had renal surgical history. Doppler ultrasound-guided PCNL with 2-step tract dilation were performed. Stones were fragmented and cleared using a combination of ultrasonic and pneumatic lithotripters. All PCNL procedures were successful. Successful access to the collecting system was 100%. Although most of the cases (231/262) were managed satisfactorily by a single tract, a second tract was used in 31 cases. Mean operation time was 56 minutes (range 25-145). The primary stone-free rate of PCNL was 80.9%. There were 39 auxiliary procedures (13 second PCNL and 26 extracorporeal shock wave lithotripsy). One month after treatment, the overall stone-free rate was 92.7%. Five patients (1.9%) received blood transfusion. Eight patients (3.1%) with a postoperative fever of ≥38.5°C were cured by intravenous antibiotics. No other severe complications occurred. The mean postoperative stay was 3.8 days (range 2-12). Doppler ultrasound-guided PCNL with 2-step tract dilation for complex renal stones is safe, effective, and worthy of wider use in clinical practice. Copyright © 2012 Elsevier Inc. All rights reserved.

Transformation of dilative and contractive landslide debris into debris flows-An example from marin County, California

USGS Publications Warehouse

Fleming, R.W.; Ellen, S.D.; Algus, M.A.

1989-01-01

The severe rainstorm of January 3, 4 and 5, 1982, in the San Francisco Bay area, California, produced numerous landslides, many of which transformed into damaging debris flows. The process of transformation was studied in detail at one site where only part of a landslide mobilized into several episodes of debris flow. The focus of our investigation was to learn whether the landslide debris dilated or contracted during the transformation from slide to flow. The landslide debris consisted of sandy colluvium that was separable into three soil horizons that occupied the axis of a small topographic swale. Failure involved the entire thickness of colluvium; however, over parts of the landslide, the soil A-horizon failed separately from the remainder of the colluvium. Undisturbed samples were taken for density measurements from outside the landslide, from the failure zone and overlying material from the part of the landslide that did not mobilize into debris flows, and from the debris-flow deposits. The soil A-horizon was contractive and mobilized to flows in a process analogous to liquefaction of loose, granular soils during earthquakes. The soil B- and C-horizons were dilative and underwent 2 to 5% volumetric expansion during landslide movement that permitted mobilization of debris-flow episodes. Several criteria can be used in the field to differentiate between contractive and dilative behavior including lag time between landsliding and mobilization of flow, episodic mobilization of flows, and partial or complete transformation of the landslide. ?? 1989.

Immune responses and ultrastructural changes of hemocytes in freshwater crab Sinopotamon henanense exposed to elevated cadmium.

PubMed

Qin, Qin; Qin, Shengjuan; Wang, Lan; Lei, Wenwen

2012-01-15

Cadmium (Cd) is one of the most toxic heavy metals that can impact immunological parameters in aquatic animals. To investigate the immunotoxicity and ultrastructural changes of hemocytes, specimens of Sinopotamon henanense were exposed to different concentrations of cadmium and the differences in immunologic parameters between Cd exposure groups and control groups were investigated. Total hemocyte count (THC) in Cd-exposure groups were decreased significantly when compared with the control groups, especially in the groups treated with higher Cd concentrations and longer exposure time, while no significant differences were observed in the proportions of the three types of hemocytes. Phenoloxidase (PO) activities were significantly higher in Cd-exposure groups than the control groups. Superoxide dismutase (SOD) activities gradually increased in 7.25 and 14.5 mg L⁻¹ Cd groups, but in other higher Cd groups, they showed first increase and following decrease with the exposure time prolonged. Acid phosphatase (ACP) activities were induced at 48 h, and then decreased, while alkaline phosphatase (AKP) activities increased gradually until 96 h. Electron microscopic results showed that nucleus, mitochondria and rough endoplasm recutulum (rER) of three types of hemocytes were sensitive to acute Cd toxicity. In Cd-exposed groups, chromatin condensation, nucleus deformation and nucleus envelope rupture were noted. Additionally, mitochondrial dilation and rER degranulation were observed in Cd-treated crabs. These results suggested that immune response and organelles of hemocyte of S. henanense were impacted by Cd exposure, and the changes of these immunologic parameters reflect changes in crab immune response capability consequent to Cd exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

The effect of bone tunnel dilation versus extraction drilling on the initial fixation strength of press-fit anterior cruciate ligament reconstruction.

PubMed

Dargel, Jens; Schmidt-Wiethoff, Rüdiger; Brüggemann, Gert-Peter; Koebke, Jürgen

2007-11-01

Serial dilation of the bone tunnel has been reported to create a tighter graft-tunnel fit. It was hypothesized that a serial dilation of the femoral bone tunnel would increase the initial fixation strength in press-fit anterior cruciate ligament (ACL) reconstructive surgery. Initial fixation strength of the femoral press-fit fixation technique was investigated in 72 porcine specimens in an ex vivo study by varying the femoral tunnel preparation technique. Extraction-drilling, tunnel dilation by 1 mm and dilation by 2.5 mm were assessed. Initial fixation strength of press-fit fixated patellar tendon-bone grafts was tested within each preparation group conducting a single cycle (and cyclic) load to failure protocol. The resulting tunnel diameter and the porcine femoral bone mineral density were determined using microradiographs and peripheral quantitative CT scans, respectively. Dilating a previously extraction-drilled femoral bone tunnel by 1 mm significantly enhances initial press-fit fixation strength in both single cycle and cyclic load to failure testing when compared to extraction-drilling and tunnel dilation by 2.5 mm. Due to an initial spring-back effect the resulting diameter of the femoral tunnel was underestimated by 3.3% with drilling and 6.7 and 12.2% with dilation by 1 and 2.5 mm, respectively. Volumetric trabecular bone mineral density at the site corresponding to the area of tunnel placement averaged 318 mg/cm(3). Dilating a femoral tunnel that is underdrilled by 1 mm appears to be a reasonable technical procedure in order to enhance initial fixation strength of press-fit ACL graft fixation.

Comparing the 12-month patency of low- versus high-pressure dilation in failing arteriovenous fistulae: A prospective multicenter trial (YOROI study).

PubMed

Wakamoto, Koki; Doi, Shigehiro; Nakashima, Ayumu; Kawai, Toru; Kyuden, Yasufumi; Naito, Takayuki; Asai, Mariko; Takahashi, Shunsuke; Murakami, Masaaki; Masaki, Takao

2018-03-01

This study was performed to investigate the effect of the balloon dilation pressure on the 12-month patency rate in patients with failed arteriovenous fistulas undergoing hemodialysis. In this multicenter, prospective, randomized trial, the 4-mm-diameter YOROI balloon was used for dilation of stenotic lesions. The balloons were inflated to a pressure of 8 atm (low-pressure group) or 30 atm to achieve complete expansion (high-pressure group). The 12-month patency rate after balloon angioplasty was analyzed by the Kaplan-Meier method and log-rank test and/or a Cox proportional hazard model. We also investigated the dilation pressure required to achieve complete expansion in the high-pressure group. In total, 71 patients were enrolled and allocated to either the low-pressure group (n = 34) or the high-pressure group (n = 37). The 12-month patency rates showed no significant difference between the low- and high-pressure groups (47% and 49%, respectively; p = 0.87). In the low-pressure group, the patency rate was not different between patients with complete dilation and residual stenosis (44% and 50%, respectively; p = 0.87). The Cox proportional hazard model revealed that the 12-month patency rate was associated with the stenosis diameter (hazard ratio 0.36; p = 0.001) and the presence of diabetes (hazard ratio 0.33; p = 0.018). Finally, the pressure required to achieve complete dilation was ≤20 atm in 76% of patients and ≤30 atm in 97% of patients. One patient required a dilation pressure of >30 atm. The patency rate does not differ between low-pressure dilation and high-pressure dilation.

The evolution of fracture surface roughness and its dependence on slip

NASA Astrophysics Data System (ADS)

Wells, Olivia L.

Under effective compression, impingement of opposing rough surfaces of a fracture can force the walls of the fracture apart during slip. Therefore, a fracture's surface roughness exerts a primary control on the amount of dilation that can be sustained on a fracture since the opposing surfaces need to remain in contact. Previous work has attempted to characterize fracture surface roughness through topographic profiles and power spectral density analysis, but these metrics describing the geometry of a fracture's surface are often non-unique when used independently. However, when combined these metrics are affective at characterizing fracture surface roughness, as well as the mechanisms affecting changes in roughness with increasing slip, and therefore changes in dilation. These mechanisms include the influence of primary grains and pores on initial fracture roughness, the effect of linkage on locally increasing roughness, and asperity destruction that limits the heights of asperities and forms gouge. This analysis reveals four essential stages of dilation during the lifecycle of a natural fracture, whereas previous slip-dilation models do not adequately address the evolution of fracture surface roughness: (1) initial slip companied by small dilation is mediated by roughness controlled by the primary grain and pore dimensions; (2) rapid dilation during and immediately following fracture growth by linkage of formerly isolated fractures; (3) wear of the fracture surface and gouge formation that minimizes dilation; and (4) between slip events cementation that modifies the mineral constituents in the fracture. By identifying these fundamental mechanisms that influence fracture surface roughness, this new conceptual model relating dilation to slip has specific applications to Enhanced Geothermal Systems (EGS), which attempt to produce long-lived dilation in natural fractures by inducing slip.

Endovascular Treatment for Fusiform Dilation of Internal Carotid Artery Following Craniopharyngioma Resection: A Case Illustration.

PubMed

Li, Qiang; Wang, Chaohua; Xu, Jianguo; You, Chao

2015-09-01

Fusiform dilation of the internal carotid artery complicates aggressive craniopharyngioma resection and occurs mainly in children. We report a case to describe the availability of endovascular treatment for this rare entity. A 13-year-old boy presented with headache for 2 years after resection of craniopharyngioma. A fusiform dilation of the right carotid artery was found and was coiled using stent-assisted technique. Follow-up showed satisfactory outcome and disappearance of headache. To our knowledge, this is the first report regarding endovascular treatment for fusiform dilation of the internal carotid artery after craniopharyngioma resection. Stent-assisted coiling is a useful approach for fusiform dilation of the internal carotid artery following craniopharyngioma surgery. © The Author(s) 2014.

Fractal dimension of trabecular bone projection texture is related to three-dimensional microarchitecture.

PubMed

Pothuaud, L; Benhamou, C L; Porion, P; Lespessailles, E; Harba, R; Levitz, P

2000-04-01

The purpose of this work was to understand how fractal dimension of two-dimensional (2D) trabecular bone projection images could be related to three-dimensional (3D) trabecular bone properties such as porosity or connectivity. Two alteration processes were applied to trabecular bone images obtained by magnetic resonance imaging: a trabeculae dilation process and a trabeculae removal process. The trabeculae dilation process was applied from the 3D skeleton graph to the 3D initial structure with constant connectivity. The trabeculae removal process was applied from the initial structure to an altered structure having 99% of porosity, in which both porosity and connectivity were modified during this second process. Gray-level projection images of each of the altered structures were simply obtained by summation of voxels, and fractal dimension (Df) was calculated. Porosity (phi) and connectivity per unit volume (Cv) were calculated from the 3D structure. Significant relationships were found between Df, phi, and Cv. Df values increased when porosity increased (dilation and removal processes) and when connectivity decreased (only removal process). These variations were in accordance with all previous clinical studies, suggesting that fractal evaluation of trabecular bone projection has real meaning in terms of porosity and connectivity of the 3D architecture. Furthermore, there was a statistically significant linear dependence between Df and Cv when phi remained constant. Porosity is directly related to bone mineral density and fractal dimension can be easily evaluated in clinical routine. These two parameters could be associated to evaluate the connectivity of the structure.

Heart rate turbulence in healthy dogs and dogs with dilated cardiomyopathy.

PubMed

Noszczyk-Nowak, A

2012-01-01

Heart rate turbulence (HRT) is modulated by the baroreceptor reflex and it was suggested that it could be used as a measure of autonomic dysfunction. Impaired HRT is of a significant prognostic value in humans after myocardial infarction, suffering from dilated cardiomyopathy and patients with heart failure. So far no studies were performed assessing the importance of HRT in dogs. The aim of this study was to prospectively evaluate the HRT turbulence onset (TO) and the turbulence slope (TS) in healthy dogs and in dogs with DCM and to compare the HRT in dogs with DCM that died during the first 30 days of observation and dogs with DCM that survived the first 30 days after the HRT analysis. The current study was aimed at determining reference value of the TO and TS of HRT in healthy dogs (control group) and dogs with dilated cardiomyopathy (DCM group). The tests were carried out on 30 healthy dogs and 30 dogs with DCM composed of Boxers, Doberman pinschers and Great Danes, of different sexes and body weights from 22 to 72 kg, aged between 1.5 and 11.5 years, submitted to the 24-hour Holter monitoring. HRT parameters were calculated using an HolCard software algorithm. TO is a percentage difference between the heart rate immediately following ventricular premature complex (VPC) and the heart rate immediately preceding VPC. TS corresponds to the steepest slope of the linear regression line for each sequence of five consecutive normal intervals in the local tachogram. The average TO in healthy dogs was determined as -13.55 +/- 11.12%, TS was 21.33 +/- 9.66 ms/RR. TO in dogs with DCM was determined as - 2.61 +/- 2.1% and TS was 6.15 +/- 3.86 ms/RR. Parameters of HRT were statistically significantly decreased (p < 0.01) in dogs with DCM. HRT TO and TS were statistically significantly decreased in dogs with DCM. Dogs with DCM that survived more than 30 days of observation had HRT statistically significantly decreased in comparison to dogs with DCM that died after the 30'th day of observation. Decreased HRT parameters in dogs with DCM suggest an autonomic neuropathy which principally consists of the withdrawal of the cardiac parasympathetic tone. The more the autonomic neuropathy is advanced the faster the death of the dog with DCM might occur, with no correlation with the level of the heart failure.

POEM is a cost-effective procedure: cost-utility analysis of endoscopic and surgical treatment options in the management of achalasia.

PubMed

Miller, Heidi J; Neupane, Ruel; Fayezizadeh, Mojtaba; Majumder, Arnab; Marks, Jeffrey M

2017-04-01

Achalasia is a rare motility disorder of the esophagus. Treatment is palliative with the goal of symptom remission and slowing the progression of the disease. Treatment options include per oral endoscopic myotomy (POEM), laparoscopic Heller myotomy (LM) and endoscopic treatments such as pneumatic dilation (PD) and botulinum toxin type A injections (BI). We evaluate the economics and cost-effectiveness of treating achalasia. We performed cost analysis for POEM, LM, PD and BI at our institution from 2011 to 2015. Cost of LM was set to 1, and other procedures are presented as percentage change. Cost-effectiveness was calculated based on cost, number of interventions required for optimal results for dilations and injections and efficacy reported in the current literature. Incremental cost-effectiveness ratio was calculated by a cost-utility analysis using quality-adjusted life year gained, defined as a symptom-free year in a patient with achalasia. Average number of interventions required was 2.3 dilations or two injections for efficacies of 80 and 61 %, respectively. POEM cost 1.058 times the cost of LM, and PD and BI cost 0.559 and 0.448 times the cost of LM. Annual cost per cure over a period of 4 years for POEM, and LM were consistently equivalent, trending the same as PD although this has a lower initial cost. The cost per cure of BI remains stable over 3 years and then doubles. The cost-effectiveness of POEM and LM is equivalent. Myotomy, either surgical or endoscopic, is more cost-effective than BI due to high failure rates of the economical intervention. When treatment is being considered BI should be utilized in patients with less than 2-year life expectancy. Pneumatic dilations are cost-effective and are an acceptable approach to treatment of achalasia, although myotomy has a lower relapse rate and is cost-effective compared to PD after 2 years.

Stand alone totally endoscopic epimyocardial ablation in patients with persistent atrial fibrillation and significant atrial dilatation.

PubMed

Wagner, Florian Mathias; Pecha, Simon; Conradi, Lenard; Reichenspurner, Hermann

2015-05-01

To analyze safety and efficacy of surgical totally endoscopic epimyocardial ablation in patients (pts) turned down for interventional catheter therapy due to long-standing persistent atrial fibrillation (pAF) combined with significant atrial dilatation (> 5 cm). Since December 2010, 15 pts were referred for surgical ablation due to persistent AF combined with biatrial dilatation (left atrium [LA] 5.0 ± 0.6 cm). Mean age was 52 ± 6 years, body mass index (BMI) 38 ± 6, duration of AF 2.8 ± 1.2 years, left ventricular end diastolic diameter (LVEDD) 5.8 cm ± 0.6 cm. Ablation was performed via a bilateral endoscopic approach using bipolar RF energy application. Monitoring was achieved by an event recorder (Reveal XT Medtronic, Inc., Minneapolis, MN, USA) or repeated 24-hours Holter electrocardiogram. All pts successfully received bilateral pulmonary vein isolation + box lesion + trigonal lesion + left atrial appendage resection. Mean duration of procedure was 235 ± 70 minutes. There was no intraoperative complication; however, one patient had persistent left phrenic nerve palsy. Mean hospital stay was 4 ± 2 days, mean follow-up time was 21 ± 11 months. Incidence of sinus rhythm (SR) was 67, 73, and 80% at discharge, three months, and 12 months follow-up. Mean LA diameter was reduced from 58.1 mm ± 6.0 mm preoperative to 49.7 mm ± 5.4 mm (p = 0.004) at 12 months follow-up. Incidence of SR was 86% at latest follow-up (mean time 21 months). All pts currently in SR (13/15 = 86%) are of class I or III antiarrhythmic drugs. Totally endoscopic left atrial ablation including left atrial resection can safely be performed. It achieved excellent rates of SR restoration in patients with long-standing persistent AF combined with significant atrial dilatation. © 2015 Wiley Periodicals, Inc.

21 CFR 876.5470 - Ureteral dilator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ureteral dilator. 876.5470 Section 876.5470 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5470 Ureteral dilator. (a...

21 CFR 876.5520 - Urethral dilator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urethral dilator. 876.5520 Section 876.5520 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5520 Urethral dilator. (a...

21 CFR 876.5365 - Esophageal dilator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Esophageal dilator. 876.5365 Section 876.5365 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5365 Esophageal dilator. (a...

21 CFR 876.5470 - Ureteral dilator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ureteral dilator. 876.5470 Section 876.5470 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5470 Ureteral dilator. (a...

Incidence and management of benign anastomotic stricture after cervical oesophagogastrostomy.

PubMed

Pierie, J P; de Graaf, P W; Poen, H; van der Tweel, I; Obertop, H

1993-04-01

Benign anastomotic stricture after transhiatal oesophagectomy and gastric tube reconstruction constitutes a major problem. From August 1988 to April 1991, 81 patients were followed after cervical oesophagogastrostomy. Twenty-four patients (30 per cent) developed a benign anastomotic stricture 3-23 (median 8) weeks after operation. Poor vascularization of the gastric tube, determined during operation, and postoperative anastomotic leakage were statistically significant risk factors for stricture formation. Symptoms related to stricture were often typical and were confirmed by endoscopy and/or radiography. Radiography did not yield information additional to that obtained from endoscopy. Strictures were treated in the outpatient clinic by dilatation with Savary dilators. Repeated dilatation completely alleviated dysphagia in 20 of the 24 patients (83 per cent). In ten patients dilatations could be discontinued after a median of 8 (range 1-17) sessions. Dilatation was continued until the end of follow-up in nine patients or until death from recurrent disease in five. No complications of dilatation were seen.

Mitomycin-C: 'a ray of hope' in refractory corrosive esophageal strictures.

PubMed

Nagaich, N; Nijhawan, S; Katiyar, P; Sharma, R; Rathore, M

2014-04-01

Increasingly frequent dilation may become a self-defeating cycle in refractory stricture as recurrent trauma enhance, scar formation, and ultimately recurrence and potential worsening of the stricture. In 12 patients of caustic induced esophageal stricture, who failed to respond despite rigorous dilatation regimen for more than one year, a trial of topical mitomycin-C application to improve dilatation results was undertaken, considering the recently reported efficacy and safety of this agent. Mitomycin-C was applied for 2-3 minutes at the strictured esophageal segment after dilation with wire-guided Savary-Gilliard dilator. Patient was kept nil by mouth for 2-3 hours. After 4-6 sessions of mitomycin-C treatment, resolution of symptoms and significant improvement in dysphagia score and periodic dilatation index was seen in all 12 patients. Mitomycin-C topical application may be a useful strategy in refractory corrosive esophageal strictures and salvage patients from surgery. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Evaluation of Mass Filtered, Time Dilated, Time-of-Flight Mass Spectrometry

DTIC Science & Technology

2010-01-01

Figure 4.4: Mass resolution dependence on field for selected actinides and surrogates...45 Figure 4.7: Mass resolution dependence on field for selected actinides and actinide surrogates, modeled with no initial...system. A somewhat better mass resolution would need to be achieved in order to separate hydride molecules in the actinide region. However, the

Total plasma proANP increases with atrial dilatation in horses.

PubMed

Van Der Vekens, N; Hunter, I; Timm, A; Decloedt, A; De Clercq, D; Deprez, P; Goetze, J P; van Loon, G

2015-12-19

Equine atrial natriuretic peptide (ANP) plasma concentrations are correlated with left atrial size. However, species-specific assays are lacking and the results from human assays are poorly reproducible. A new methodology called processing independent analysis (PIA) that measures the total proANP product in plasma has proven to be successful in human medicine, but has never been used in horses. The aims were to establish an equine proANP reference interval by measurement of the total proANP product using PIA and to examine the proANP concentrations in horses with atrial dilatation. Sample stability was studied by comparison of storage at -80°C and -20°C. Plasma samples were obtained from 23 healthy horses, 12 horses with moderate or severe valvular regurgitation without atrial dilatation and 42 horses with valvular regurgitation and atrial dilatation. The proANP concentration was significantly (P<0.001) higher in horses with atrial dilatation (761.4 (442.1-1859.1) pmol/l) than in healthy horses (491.6 (429.5-765.9) pmol/l; P<0.001) or horses with cardiac disease but without atrial dilatation (544.4 (457.0-677.6) pmol/l). A cut-off value (573.8 pmol/l) for detection of atrial dilatation was calculated. Sample storage at -80°C did not differ from sample storage at -20°C. The measurement of total proANP in plasma detects atrial dilatation in horses and may be useful for clinical evaluation in equine medicine. British Veterinary Association.

Topical mitomycin-C application in recurrent esophageal strictures after surgical repair of esophageal atresia.

PubMed

Chapuy, Laurence; Pomerleau, Martine; Faure, Christophe

2014-11-01

The aim of the present study was to evaluate the efficacy and short-term safety of topical mitomycin-C, an antifibrotic agent, in preventing the recurrence of anastomotic strictures after surgical repair of esophageal atresia (EA). We retrospectively reviewed the medical records of patients with recurrent anastomotic strictures after EA surgery who underwent at least 3 esophageal dilations. We compared the outcome (ie, resolution of the stricture) of the group that received topical mitomycin-C treatment with endoscopic esophageal dilation with a historical cohort treated by dilations alone. A total of 11 children received mitomycin-C concurrently with endoscopic dilations. After a median follow-up of 33 months (range 18-72), and a mean number of 5.4 dilations per patient (range 3-11), 8 of 11 patients achieved a resolution of their strictures, 2 patients remained with stenosis, and 1 patient needed a surgical correction. In the control group, 10 patients required an average of 3.7 (range 3-7) total dilations. After a follow-up of 125 months (range 35-266) after the last dilation, strictures in 9 of 10 children disappeared and the remaining patient was symptom free. No dysplasia related to mitomycin-C was demonstrated. There is no benefit in the resolution of the stricture when adding mitomycin-C treatment compared with repeated esophageal dilations alone in historical controls. Further randomized controlled studies and a short- and long-term evaluation of safety are needed.

Progression of the first stage of spontaneous labour: A prospective cohort study in two sub-Saharan African countries

PubMed Central

Fawole, Bukola; Mugerwa, Kidza; Alves, Domingos; Souza, Hayala; Reis, Rodrigo; Oliveira-Ciabati, Livia; Maiorano, Alexandre; Akintan, Adesina; Alu, Francis E.; Oyeneyin, Lawal; Adebayo, Amos; Byamugisha, Josaphat; Idris, Hadiza A.; Okike, Ola; Althabe, Fernando; Hundley, Vanora; Pattinson, Robert; Sanghvi, Harshadkumar C.; Tunçalp, Özge; Vogel, Joshua P.; Stanton, Mary Ellen; Liljestrand, Jerker; ten Hoope-Bender, Petra; Mathai, Matthews; Bahl, Rajiv

2018-01-01

Background Escalation in the global rates of labour interventions, particularly cesarean section and oxytocin augmentation, has renewed interest in a better understanding of natural labour progression. Methodological advancements in statistical and computational techniques addressing the limitations of pioneer studies have led to novel findings and triggered a re-evaluation of current labour practices. As part of the World Health Organization's Better Outcomes in Labour Difficulty (BOLD) project, which aimed to develop a new labour monitoring-to-action tool, we examined the patterns of labour progression as depicted by cervical dilatation over time in a cohort of women in Nigeria and Uganda who gave birth vaginally following a spontaneous labour onset. Methods and findings This was a prospective, multicentre, cohort study of 5,606 women with singleton, vertex, term gestation who presented at ≤ 6 cm of cervical dilatation following a spontaneous labour onset that resulted in a vaginal birth with no adverse birth outcomes in 13 hospitals across Nigeria and Uganda. We independently applied survival analysis and multistate Markov models to estimate the duration of labour centimetre by centimetre until 10 cm and the cumulative duration of labour from the cervical dilatation at admission through 10 cm. Multistate Markov and nonlinear mixed models were separately used to construct average labour curves. All analyses were conducted according to three parity groups: parity = 0 (n = 2,166), parity = 1 (n = 1,488), and parity = 2+ (n = 1,952). We performed sensitivity analyses to assess the impact of oxytocin augmentation on labour progression by re-examining the progression patterns after excluding women with augmented labours. Labour was augmented with oxytocin in 40% of nulliparous and 28% of multiparous women. The median time to advance by 1 cm exceeded 1 hour until 5 cm was reached in both nulliparous and multiparous women. Based on a 95th percentile threshold, nulliparous women may take up to 7 hours to progress from 4 to 5 cm and over 3 hours to progress from 5 to 6 cm. Median cumulative duration of labour indicates that nulliparous women admitted at 4 cm, 5 cm, and 6 cm reached 10 cm within an expected time frame if the dilatation rate was ≥ 1 cm/hour, but their corresponding 95th percentiles show that labour could last up to 14, 11, and 9 hours, respectively. Substantial differences exist between actual plots of labour progression of individual women and the ‘average labour curves’ derived from study population-level data. Exclusion of women with augmented labours from the study population resulted in slightly faster labour progression patterns. Conclusions Cervical dilatation during labour in the slowest-yet-normal women can progress more slowly than the widely accepted benchmark of 1 cm/hour, irrespective of parity. Interventions to expedite labour to conform to a cervical dilatation threshold of 1 cm/hour may be inappropriate, especially when applied before 5 cm in nulliparous and multiparous women. Averaged labour curves may not truly reflect the variability associated with labour progression, and their use for decision-making in labour management should be de-emphasized. PMID:29338000

21 CFR 876.5450 - Rectal dilator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rectal dilator. 876.5450 Section 876.5450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5450 Rectal dilator. (a) Identification. A rectal...

Pregnancy rates after ewes were treated with estradiol-17beta and oxytocin.

USDA-ARS?s Scientific Manuscript database

Cervical dilation may improve transcervical sheep embryo-transfer procedures, if the cervical dilation method does not reduce pregnancy rates. This experiment was conducted to determine whether estradiol-17beta-oxytocin treatment, which dilates the cervix in luteal-phase ewes, affects pregnancy rat...

21 CFR 876.5450 - Rectal dilator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Rectal dilator. 876.5450 Section 876.5450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5450 Rectal dilator. (a) Identification. A rectal...

Relativity on a Spreadsheet.

ERIC Educational Resources Information Center

Carson, S. R.

1998-01-01

Presents a method for using spreadsheets to model special relativistic phenomena based on the connection between electric and magnetic fields in special relativity. Uses the time dilation equation to carry out transformations between reference frames that show the connection between the fields quantitatively. (DDR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosello-Lleti, Esther; Rivera, Miguel; Cortes, Raquel

Highlights: Black-Right-Pointing-Pointer Heart failure alters nucleolar morphology and organization. Black-Right-Pointing-Pointer Nucleolin expression is significant increased in ischemic and dilated cardiomyopathy. Black-Right-Pointing-Pointer Ventricular function of heart failure patients was related with nucleolin levels. -- Abstract: We investigate for the first time the influence of heart failure (HF) on nucleolar organization and proteins in patients with ischemic (ICM) or dilated cardiomyopathy (DCM). A total of 71 human hearts from ICM (n = 38) and DCM (n = 27) patients, undergoing heart transplantation and control donors (n = 6), were analysed by western-blotting, RT-PCR and cell biology methods. When we compared protein levelsmore » according to HF etiology, nucleolin was increased in both ICM (117%, p < 0.05) and DCM (141%, p < 0.01). Moreover, mRNA expression were also upregulated in ICM (1.46-fold, p < 0.05) and DCM (1.70-fold, p < 0.05. Immunofluorescence studies showed that the highest intensity of nucleolin was into nucleolus (p < 0.0001), and it was increased in pathological hearts (p < 0.0001). Ultrastructure analysis by electron microscopy showed an increase in the nucleus and nucleolus size in ICM (17%, p < 0.05 and 131%, p < 0.001) and DCM (56%, p < 0.01 and 69%, p < 0.01). Nucleolar organization was influenced by HF irrespective of etiology, increasing fibrillar centers (p < 0.001), perinucleolar chromatin (p < 0.01) and dense fibrillar components (p < 0.01). Finally, left ventricular function parameters were related with nucleolin levels in ischemic hearts (p < 0.0001). The present study demonstrates that HF influences on morphology and organization of nucleolar components, revealing changes in the expression and in the levels of nucleolin protein.« less

Mechanisms of right ventricular electromechanical dyssynchrony and mechanical inefficiency in children after repair of tetralogy of fallot.

PubMed

Hui, Wei; Slorach, Cameron; Dragulescu, Andreea; Mertens, Luc; Bijnens, Bart; Friedberg, Mark K

2014-07-01

Right bundle branch block and right ventricular (RV) dysfunction are common after tetralogy of Fallot repair (rTOF). We hypothesized that right bundle branch block is associated with specific RV mechanical dyssynchrony and inefficient contraction. We studied rTOF children and age-matched controls. QRS duration and morphology were assessed. RV mechanical dyssynchrony, indicated by early septal activation (right-sided septal flash), RV lateral wall prestretch/late contraction, postsystolic shortening, and intraventricular delay were analyzed using 2-dimensional strain echocardiography. Peak oxygen consumption reflected exercise capacity. Pulmonary regurgitation and RV volumes were assessed by MRI. Forty-six rTOF patients and 46 controls were studied. Ninety-three percent of rTOF patients demonstrated a right-sided septal flash with simultaneous RV basal lateral wall prestretch/late activation. The RV basal segment was the most delayed in onset (115 [0-194] versus 35 [0-96] ms) and termination (462 [369-706] versus 412 [325-529] ms) of longitudinal shortening, with postsystolic shortening. QRS duration correlated with RV basal time to onset and peak shortening (P<0.05). Intra-RV delay was higher in rTOF (P<0.05) in association with RV dilatation (r=0.33; P=0.04). In rTOF, RV mechanics were inefficient, with prestretch and postsystolic shortening comprising 15±11% and 16±9% of total shortening, respectively. A composite parameter of electric and mechanical dyssynchrony correlated with RV end-diastolic volume (r=0.39; P=0.03). Typical electromechanical dyssynchrony associated with mechanical inefficiency, regional dysfunction, and RV dilatation is common in rTOF children, possibly contributing to progressive RV dysfunction. The potential of cardiac resynchronization in appropriate patients requires further study. © 2014 American Heart Association, Inc.

The preparatory phase of the April 6th 2009, Mw 6.3, L’Aquila earthquake: Seismological observations

NASA Astrophysics Data System (ADS)

Lucente, F. P.; de Gori, P.; Margheriti, L.; Piccinini, D.; Dibona, M.; Chiarabba, C.; Piana Agostinetti, N.

2009-12-01

Few decades ago, the dilatancy-diffusion hypothesis held great promise as a physical basis for developing earthquakes prediction techniques, but the potential never become reality, as the result of too few observations consistent with the theory. One of the main problems has been the lack of detailed monitoring records of small earthquakes swarms spatio-temporally close to the incoming major earthquakes. In fact, the recognition of dilatancy-related effects requires the use of very dense network of three-component seismographs, which, in turn, implies the a-priori knowledge of major earthquakes location, i.e., actually a paradox. The deterministic prediction of earthquakes remains a long time, hard task to accomplish. Nevertheless, for seismologists, the understanding of the processes that preside over the earthquakes nucleation and the mechanics of faulting represents a big step toward the ability to predict earthquakes. Here we describe a set of seismological observations done on the foreshock sequence that preceded the April 6th 2009, Mw 6.3, L’Aquila earthquake. In this occasion, the dense configuration of the seismic network in the area gave us the unique opportunity for a detailed reconstruction of the preparatory phase of the main shock. We show that measurable precursory effects, as changes of the seismic waves velocity and of the anisotropic parameters in the crust, occurred before the main shock. From our observations we infer that fluids play a key role in the fault failure process, and, most significantly, that the elastic properties of the rock volume surrounding the main shock nucleation area undergo a dramatic change about a week before the main shock occurrence.

Characterization and Long-Term Prognosis of Postmyocarditic Dilated Cardiomyopathy Compared With Idiopathic Dilated Cardiomyopathy.

PubMed

Merlo, Marco; Anzini, Marco; Bussani, Rossana; Artico, Jessica; Barbati, Giulia; Stolfo, Davide; Gigli, Marta; Muça, Matilda; Naso, Paola; Ramani, Federica; Di Lenarda, Andrea; Pinamonti, Bruno; Sinagra, Gianfranco

2016-09-15

Dilated cardiomyopathy (DC) is the final common pathway of different pathogenetic processes and presents a significant prognostic heterogeneity, possibly related to its etiologic variety. The characterization and long-term prognosis of postmyocarditic dilated cardiomyopathy (PM-DC) remain unknown. This study assesses the clinical-instrumental evolution and long-term prognosis of a large cohort of patients with PM-DC. We analyzed 175 patients affected with DC consecutively enrolled from 1993 to 2008 with endomyocardial biopsy (EMB) data available. PM-DC was defined in the presence of borderline myocarditis at EMB or persistent left ventricular dysfunction 1 year after diagnosis of active myocarditis at EMB. Other patients were defined as affected by idiopathic dilated cardiomyopathy (IDC). Analysis of follow-up evaluations was performed at 24, 60, and 120 months. We found 72 PM-DC of 175 enrolled patients (41%). Compared with IDC, patients with PM-DC were more frequently females and less frequently presented a familial history of DC. No other baseline significant differences were found. During the long-term follow-up (median 154, first to third interquartile range 78 to 220 months), patients with PM-DC showed a trend toward slower disease progression. Globally, 18 patients with PM-DC (25%) versus 49 with IDC (48%) experienced death/heart transplantation (p = 0.045). The prognostic advantage for patients with PM-DC became significant beyond 40 months of follow-up. At multivariable time-dependent Cox analysis, PM-DC was confirmed to have a global independent protective role (hazard ratio 0.53, 95% confidence interval 0.28 to 0.97, p = 0.04). In conclusion, PM-DC is characterized by better long-term prognosis compared with IDC. An exhaustive etiologic characterization appears relevant in the prognostic assessment of DC. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of zofenopril and lisinopril to study the role of the sulfhydryl-group in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure

PubMed Central

Buikema, H; Monnink, S H J; Tio, R A; Crijns, H J G M; de Zeeuw, D; van Gilst, W H

2000-01-01

We evaluated the role of SH-groups in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure. To this end, we compared the vasoprotective effect of chronic treatment with zofenopril (plus SH-group) versus lisinopril (no SH-group), or N-acetylcysteine (only SH-group) in myocardial infarcted (MI) heart failure rats.After 11 weeks of treatment, aortas were obtained and studied as ring preparations for endothelium-dependent and -independent dilatation in continuous presence of indomethacin to avoid interference of vasoactive prostanoids, and the selective presence of the NOS-inhibitor L-NMMA to determine NO-contribution.Total dilatation after receptor-dependent stimulation with acetylcholine (ACh) was attenuated (−49%, P<0.05) in untreated MI (n=11), compared to control rats with no-MI (n=8). This was in part due to impaired NO-contribution in MI (−50%, P<0.05 versus no-MI). At the same time the capacity for generation of biologically active NO after receptor-independent stimulation with A23187 remained intact.Chronic treatment with n-acetylcysteine (n=8) selectively restored NO-contribution in total dilatation to ACh. In contrast, both ACE-inhibitors fully normalized total dilatation to ACh, including the part mediated by NO (no significant differences between zofenopril (n=10) and lisinopril (n=8)).Zofenopril, but not lisinopril, additionally potentiated the effect of endogenous NO after A23187-induced release from the endothelium (+100%) as well as that of exogenous NO provided by nitroglycerin (+22%) and sodium nitrite (+36%) (for all P<0.05 versus no-MI).We conclude that ACE-inhibition with a SH-group has a potential advantage in improvement of endothelial dysfunction through increased activity of NO after release from the endothelium into the vessel wall. Furthermore, this is the first study demonstrating the selective normalizing effect of N-actylcysteine on NO-contribution to ACh-induced dilatation in experimental heart failure. PMID:10952693

Protective effects of flavanol-rich dark chocolate on endothelial function and wave reflection during acute hyperglycemia.

PubMed

Grassi, Davide; Desideri, Giovambattista; Necozione, Stefano; Ruggieri, Fabrizio; Blumberg, Jeffrey B; Stornello, Michele; Ferri, Claudio

2012-09-01

Nitric oxide plays a pivotal role in regulating vascular tone. Different studies show endothelial function is impaired during hyperglycemia. Dark chocolate increases flow-mediated dilation in healthy and hypertensive subjects with and without glucose intolerance; however, the effect of pretreatment with dark chocolate on endothelial function and other vascular responses to hyperglycemia has not been examined. Therefore, we aimed to investigate the effects of flavanol-rich dark chocolate administration on (1) flow-mediated dilation and wave reflections; (2) blood pressure, endothelin-1 and oxidative stress, before and after oral glucose tolerance test (OGTT). Twelve healthy volunteers (5 males, 28.2±2.7 years) randomly received either 100 g/d dark chocolate or flavanol-free white chocolate for 3 days. After 7 days washout period, volunteers were switched to the other treatment. Flow-mediated dilation, stiffness index, reflection index, peak-to-peak time, blood pressure, endothelin-1 and 8-iso-PGF(2α) were evaluated after each treatment phase and OGTT. Compared with white chocolate, dark chocolate ingestion improved flow-mediated dilation (P=0.03), wave reflections, endothelin-1 and 8-iso-PGF(2α) (P<0.05). After white chocolate ingestion, flow-mediated dilation was reduced after OGTT from 7.88±0.68 to 6.07±0.76 (P=0.027), 6.74±0.51 (P=0.046) at 1 and 2 h after the glucose load, respectively. Similarly, after white chocolate but not after dark chocolate, wave reflections, blood pressure, and endothelin-1 and 8-iso-PGF(2α) increased after OGTT. OGTT causes acute, transient impairment of endothelial function and oxidative stress, which is attenuated by flavanol-rich dark chocolate. These results suggest cocoa flavanols may contribute to vascular health by reducing the postprandial impairment of arterial function associated with the pathogenesis of atherosclerosis.

[Testing methods for the characterization of catheter balloons and lumina].

PubMed

Werner, C; Rössler, K; Deckert, F

1995-10-01

The present paper reports on the characterization of catheter balloons and lumina on the basis of such known parameters as residual volume, compliance, burst pressure and flow rate, with the aim of developing standards, test methods and testing equipment as well as standards. These are becoming ever more important with the coming into force of the EC directive on medical products [7] and the law governing medical products in Germany [13], which requires manufacturers to specify the properties of their products. Our testing concept is based on a commercially available machine that subjects materials to alternating extension and compression forces over the long-term, to which we added a special hydraulic module. Using the multimedia technology we achieved a real time superimposition of the volume-diameter curve on the balloon. The function of the testing device and method is demonstrated on dilatation catheters. Our initial results reveal compatibility with the requirements of the 1% accuracy class. Use of this methodology for comparative testing of catheters and quality evaluation is recommended.

Method for Experimental Verification of the Effect of Gravitational Time Dilation by Using an Active Hydrogen Maser

NASA Astrophysics Data System (ADS)

Malykin, G. B.

2015-09-01

The well-known experiments performed by Pound and Rebka already in the 1960s confirmed the effect of gravitational time dilation, which had been predicted earlier within the framework of the general relativity theory. However, since photon exchange occurred in the course of these experiments on comparing the frequencies of nuclear resonance fluorescence at various altitudes, the reasons underlying the origin of this effect are explained in the literature by two different and, in fact, alternative presumed physical phenomena. According to the first explanation, clocks locate higher run faster, which is due to an increase in the gravitational potential with increasing distance from the Earth, whereas ascending and descending photons do not change their frequency (by the same clock, e.g., that of the so-called outside observer). According to the second explanation, the clock rate is the same at different altitudes, but the ascending photons undergo a redshift since they lose their energy, while the descending photons undergo a blueshift since they acquire energy. Other combined interpretations of the gravitational time dilation, which presume that the both phenomena exist simultaneously, are proposed in the literature. We propose an experiment with two clocks being active hydrogen masers, one of which is located at the bottom of a high-rise building, and the other, on the top of the building. In this case, time is measured by the first and second clocks during a sufficiently long time interval. After that, the masers are placed at one point, and their indications are compared. In this case, the photon exchange is not required for comparison of the clock readings, and, therefore, the method proposed allows one to reveal the actual reason of the effect under consideration. Numerical estimations are made, which allow for the accompanying effects influencing the measurement accuracy. Critical analysis of the earlier experiments shows that they are either equivocal, or are not absolutely impeccable from the methodology viewpoint.

Dilated Canine Hearts: A Specimen for Teaching Cardiac Anatomy

ERIC Educational Resources Information Center

Cope, Lee Anne

2008-01-01

Dilated canine hearts were used to teach undergraduate students internal and external cardiac anatomy. The specimens were dilated using hydrostatic pressure and then fixed using 5% formalin. These specimens provided the students with an alternative to prepackaged embalmed hearts and anatomical models for studying the external and internal cardiac…

Comparison of the Eder-Puestow and Celestin techniques for dilating benign oesophageal strictures.

PubMed

Hine, K R; Hawkey, C J; Atkinson, M; Holmes, G K

1984-10-01

The Celestin and Eder-Puestow methods of dilating benign oesophageal strictures have been compared prospectively in a randomised trial. One hundred and thirty three dilatations were performed on 72 patients. There was no significant difference between the two techniques with regard to the long term relief of symptoms. Celestin dilatation was quicker, less likely to cause pharyngeal trauma, and less damaging to guide wires. It could not be used, however, in those patients in whom only a short length of guide wire could be passed through the stricture.

Comparison of the Eder-Puestow and Celestin techniques for dilating benign oesophageal strictures.

PubMed Central

Hine, K R; Hawkey, C J; Atkinson, M; Holmes, G K

1984-01-01

The Celestin and Eder-Puestow methods of dilating benign oesophageal strictures have been compared prospectively in a randomised trial. One hundred and thirty three dilatations were performed on 72 patients. There was no significant difference between the two techniques with regard to the long term relief of symptoms. Celestin dilatation was quicker, less likely to cause pharyngeal trauma, and less damaging to guide wires. It could not be used, however, in those patients in whom only a short length of guide wire could be passed through the stricture. PMID:6479685

[Results of percutaneous transluminal dilatation of cerebral vascular stenoses].

PubMed

Kachel, R; Ritter, H; Grossmann, K; Glaser, F H

1986-03-01

The present paper is a review of 37 successful catheter dilatations of supra-aortic vascular stenoses. There were sixteen patients with a total of 21 stenoses of the internal carotid, vertebral artery or common carotid artery and sixteen patients with subclavian stenoses. Amongst the patients with stenoses of the cerebral vessels, there were ten with multiple lesions and six with a single stenosis. Three patients had successful dilatations of bilateral stenoses. The indications, technique, and complications of catheter dilatation of lesions of the cerebral vessels are described and discussed.

Pathologic aneurysmal dilation of the ascending aorta and dilation of the main pulmonary artery in patients with Kabuki syndrome: valve-sparing aortic root replacement.

PubMed

Dyamenahalli, Umesh; Abraham, Boban; Fontenot, Eudice; Prasad, Vinay; Imamura, Michiaki

2007-01-01

We report the aneurysmal dilation of the ascending aorta and the main pulmonary artery in 2 children with Kabuki syndrome. In 1 patient, there was progressive aneurysmal dilation of the ascending aorta necessitating aortoplasty. Histologic examination of the resected aorta revealed disrupted and fragmented elastic fibers in the medial layer, along with mucinous degeneration of the aortic wall. This is the first recognition and report of these findings as part of the Kabuki syndrome.

FATAL GASTRIC DILATION IN TWO ADULT BLACK-FOOTED FERRETS (MUSTELA NIGRIPES).

PubMed

Hinton, Jenna D; Aitken-Palmer, Copper; Joyner, Priscilla H; Ware, Lisa; Walsh, Timothy F

2016-03-01

Acute gastric dilation resulting in death was identified in two adult black-footed ferrets (Mustela nigripes) housed at the Smithsonian Conservation Biology Institute in Front Royal, Virginia. Both individuals were adult males (3 and 5 yr) and previously clinically healthy prior to the event. The etiology of gastric dilation in both cases could not be definitively determined, and necropsy revealed severe cardiovascular compromise secondary to bloat. Limited literature is available regarding a syndrome of this type in adult black-footed ferrets. Differential diagnoses considered included gastric dilatation volvulus (GDV), severe gastric distention of unknown origin, and gastric outflow obstruction. Given the severity of this syndrome and the findings in these two cases, acute gastric dilation should be considered in black-footed ferrets presenting with acute abdominal distention, respiratory distress, and cardiovascular compromise.

Mechanisms of hypoxia-induced cerebrovascular dilation in the newborn pig.

PubMed

Leffler, C W; Smith, J S; Edrington, J L; Zuckerman, S L; Parfenova, H

1997-03-01

The hypothesis that endothelium-dependent components contribute to the cerebromicrovascular dilation to hypoxia in the newborn pig was addressed. Piglets anesthetized with ketamine-acepromazine and maintained on alpha-chloralose were equipped with closed cranial windows. Injury to the endothelium of pial arterioles was produced by light activation of fluorescein dye. Light/dye injury reduced the pial arteriolar dilation to hypoxia (5 min, arterial PO2 approximately 30 mmHg) from 57 +/- 9 to 19 +/- 5%. Light/dye injury abolished the pial arteriolar dilation to hypercapnia but did not affect dilation to sodium nitroprusside. The pial arteriolar dilation to hypoxia was not affected by tetrodotoxin, N(omega)-nitro-L-arginine, glibenclamide, iberiotoxin, charybdotoxin, tetraethylammonium, or 8-phenyltheophylline. Hypoxia caused increases in the cerebral cortical production of adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate. Cerebral vasodilation to hypoxia was inhibited by 5,8,11,14-eicosatetraynoic acid but was not greatly affected by cyclooxygenase or lipoxygenase inhibitors. In contrast, the cytochrome P-450 epoxygenase inhibitor miconazol decreased cerebral vasodilation to hypoxia from 45 +/- 5 to 17 +/- 4%. Therefore, the vascular endothelium appears to participate in cerebral microvascular dilation to hypoxia in newborn pigs. The mechanism may include cytochrome P-450 epoxygenase metabolites of arachidonic acid.

Esophageal stenosis in epidermolysis bullosum: a challenge for the endoscopist.

PubMed

De Angelis, Paola; Caldaro, Tamara; Torroni, Filippo; Romeo, Erminia; Foschia, Francesca; di Abriola, Giovanni Federici; Rea, Francesca; El Hachem, May; Genovese, Elisabetta; D'Alessandro, Sandra; Dall'Oglio, Luigi

2011-05-01

Esophageal stenosis is a severe complication in dystrophic epidermolysis bullosa (EB). Endoscopic dilations may cause mucosal injury with stricture recurrence. Our aim was to describe our referral EB-center experience on safety and long-term efficacy of fluoroscopically guided balloon dilation without endoscopy. Over 14 years, 34 patients with EB, previously evaluated with barium esophagogram for dysphagia, underwent balloon esophageal dilation. Under fluoroscopy, a guide wire was introduced via a nostril into the stomach. A 12-mm pneumatic balloon, which passed over the wire, was filled using radio-opaque contrast, dilating the stricture. Orotracheal intubation was avoided. Antibiotics, dexamethasone, and proton-pump inhibitors were administered. Study approval was obtained from our ethical board. Ninety-three dilations were performed. Seventeen patients had a single stenosis. The mean age of onset was 18 years (range, 3-47 years). Thirteen patients underwent one dilation. In 6 cases, endoscopy was necessary to visualize the esophageal lumen. Complications included cervical esophageal perforation (2) and transitory dysphagia (10). Thirty patients were feeding within 24 hours. During the follow-up, 2 patients required a gastrostomy, and 2 patients underwent fundoplication for gastroesophageal reflux disease. Fluoroscopically guided balloon dilation in EB is a safe and well-tolerated procedure. An experienced endoscopy team is necessary in certain cases. Copyright © 2011 Elsevier Inc. All rights reserved.

Laser-driven short-duration heating angioplasty: dilatation performance in cadaver atherosclerotic femoral arteries

NASA Astrophysics Data System (ADS)

Shimazaki, Natsumi; Naruse, Sho; Arai, Tsunenori; Imanishi, Nobuaki; Aiso, Sadakazu

2013-03-01

The purpose of this study was to investigate the artery dilatation performance of the short-duration heating balloon catheter in cadaver stenotic arteries. We designed a prototype short-duration heating balloon catheter that can heat artery media to around 60 °C in 15-25 s by a combination of laser-driven heat generation and continuous fluid irrigation in the balloon. We performed ex vivo short-duration heating dilatation in the cadaver atherosclerotic femoral arteries (initial percent diameter stenosis was 36-98%), with the maximum balloon temperature of 65+/-5 °C, laser irradiation duration of 25 s, and balloon dilatation pressure of 3.5 atm. The artery lumen configurations before and after the dilatations were assessed with a commercial IVUS system. After the short-duration heating dilatations, the percent diameter stenosis was reduced below 30% without any artery tears or dissections. We estimated that the artery media temperature was raised to around 60 °C in which plaque thickness was below 0.8 mm by a thermal conduction calculation. The estimated maximum temperature in artery adventitia and surrounding tissue was up to 45 °C. We found that the short-duration heating balloon could sufficiently dilate the cadaver stenotic arteries, without thermal injury in artery adventitia and surroundings.

The influence of joint parameters on normal fault evolution and geometry: a parameter study using analogue modeling

NASA Astrophysics Data System (ADS)

Kettermann, Michael; von Hagke, Christoph; Urai, Janos L.

2017-04-01

Dilatant faults often form in rocks containing pre-existing joints, but the effects of joints on fault segment linkage and fracture connectivity is not well understood. Studying evolution of dilatancy and influence of fractures on fault development provides insights into geometry of fault zones in brittle rocks and will eventually allow for predicting their subsurface appearance. In an earlier study we recognized the effect of different angles between strike direction of vertical joints and a basement fault on the geometry of a developing fault zone. We now systematically extend the results by varying geometric joint parameters such as joint spacing and vertical extent of the joints and measuring fracture density and connectivity. A reproducibility study shows a small error-range for the measurements, allowing for a confident use of the experimental setup. Analogue models were carried out in a manually driven deformation box (30x28x20 cm) with a 60° dipping pre-defined basement fault and 4.5 cm of displacement. To produce open joints prior to faulting, sheets of paper were mounted in the box to a depth of 5 cm at a spacing of 2.5 cm. We varied the vertical extent of the joints from 5 to 50 mm. Powder was then sieved into the box, embedding the paper almost entirely (column height of 19 cm), and the paper was removed. During deformation we captured structural information by time-lapse photography that allows particle imaging velocimetry analyses (PIV) to detect localized deformation at every increment of displacement. Post-mortem photogrammetry preserves the final 3-dimensional structure of the fault zone. A counterintuitive result is that joint depth is of only minor importance for the evolution of the fault zone. Even very shallow joints form weak areas at which the fault starts to form and propagate. More important is joint spacing. Very large joint spacing leads to faults and secondary fractures that form subparallel to the basement fault. In contrast, small joint spacing results in fault strands that only localize at the pre-existing joints, and secondary fractures that are oriented at high angles to the pre-existing joints. With this new set of experiments we can now quantitatively constrain how (i) the angle between joints and basement fault, (ii) the joint depth and (iii) the joint spacing affect fault zone parameters such as (1) the damage zone width, (2) the density of secondary fractures, (3) map-view area of open gaps or (4) the fracture connectivity. We apply these results to predict subsurface geometries of joint-fault networks in cohesive rocks, e.g. basaltic sequences in Iceland and sandstones in the Canyonlands NP, USA.

Twelve years of chiari-like malformation and syringomyelia scanning in Cavalier King Charles Spaniels in the Netherlands: Towards a more precise phenotype

PubMed Central

Van Bruggen, Leonie W. L.; Eggelmeijer, Wieteke; Noorman, Erik; Jacques, Arnold; Buys, Nadine; Janssens, Steven

2017-01-01

Chiari-like malformation (CM), syringomyelia (SM) and middle ear effusion (also called PSOM) are three conditions that frequently occur in Cavalier King Charles Spaniels (CKCS). Both CM and SM are currently screened in the Netherlands prior to breeding and are graded according to the British Veterinary Association’s Kennel Club (BVA/KC) scheme. This study evaluated the prevalence and estimated genetic parameter of CM, SM and middle ear effusion from 12 years of screening results. For SM, the classical method using the BVA/KC scheme, was compared with exact measuring of the central canal dilation. For CM, the BVA/KC scheme was compared with a more detailed scheme. Next to this the presence of microchip artifacts was assessed. 1249 screening of 1020 dogs were re-evaluated. Results indicated the presence of CM in all dogs, suggesting it has become a breed-specific characteristic. And although different grades of CM were observed, the condition did not deteriorate over time. SM was present in 39% of the dogs and a clear age effect was demonstrated, with SM increasing with age. This emphasizes the importance of screening at appropriate age, since SM can worsen with increasing age. One alternative is to promote repeated measures. The presence of middle ear effusion in this study was 19%–21% for dogs younger than 3 years, and 32%–38% for dogs older than 3 years. In as much as 60%, microchip artifacts were noticed, leading to the recommendation to place microchips in another location in breeds that are susceptible to developing SM. Finally, this study estimated the heritability of CM in this population, due to the lack of phenotypic variance, to be very low at 0.02–0.03. The heritability for SM central canal dilatation to be 0.30, compared to 0.13 for the classical BVA/KC method, using a model including the age effect and the combined effect of veterinary clinic and year of the evaluation. Genetic correlations were rather small, ranging from 0.16–0.33. As a conclusion, screening for SM and CM in the entire population should be maintained, and a selection scheme against SM should be based on estimated breeding values for the exact measurement of the central canal dilatation. PMID:28934242

Chaotic trajectories in the standard map. The concept of anti-integrability

NASA Astrophysics Data System (ADS)

Aubry, Serge; Abramovici, Gilles

1990-07-01

A rigorous proof is given in the standard map (associated with a Frenkel-Kontorowa model) for the existence of chaotic trajectories with unbounded momenta for large enough coupling constant k > k0. These chaotic trajectories (with finite entropy per site) are coded by integer sequences { mi} such that the sequence bi = |m i+1 + m i-1-2m i| be bounded by some integer b. The bound k0 in k depends on b and can be lowered for coding sequences { mi} fulfilling more restrictive conditions. The obtained chaotic trajectories correspond to stationary configurations of the Frenkel-Kontorowa model with a finite (non-zero) photon gap (called gap parameter in dimensionless units). This property implies that the trajectory (or the configuration { ui}) can be uniquely continued as a uniformly continuous function of the model parameter k in some neighborhood of the initial configuration. A non-zero gap parameter implies that the Lyapunov coefficient is strictly positive (when it is defined). In addition, the existence of dilating and contracting manifolds is proven for these chaotic trajectories. “Exotic” trajectories such as ballistic trajectories are also proven to exist as a consequence of these theorems. The concept of anti-integrability emerges from these theorems. In the anti-integrable limit which can be only defined for a discrete time dynamical system, the coordinates of the trajectory at time i do not depend on the coordinates at time i - 1. Thus, at this singular limit, the existence of chaotic trajectories is trivial and the dynamical system reduces to a Bernoulli shift. It is well known that the KAM tori of symplectic dynamical originates by continuity from the invariant tori which exists in the integrible limit (under certain conditions). In a similar way, it appears that the chaotic trajectories of dynamical systems originate by continuity from those which exists at the anti-integrable limits (also under certain conditions).

Non-mydriatic video ophthalmoscope to measure fast temporal changes of the human retina

NASA Astrophysics Data System (ADS)

Tornow, Ralf P.; Kolář, Radim; Odstrčilík, Jan

2015-07-01

The analysis of fast temporal changes of the human retina can be used to get insight to normal physiological behavior and to detect pathological deviations. This can be important for the early detection of glaucoma and other eye diseases. We developed a small, lightweight, USB powered video ophthalmoscope that allows taking video sequences of the human retina with at least 25 frames per second without dilating the pupil. Short sequences (about 10 s) of the optic nerve head (20° x 15°) are recorded from subjects and registered offline using two-stage process (phase correlation and Lucas-Kanade approach) to compensate for eye movements. From registered video sequences, different parameters can be calculated. Two applications are described here: measurement of (i) cardiac cycle induced pulsatile reflection changes and (ii) eye movements and fixation pattern. Cardiac cycle induced pulsatile reflection changes are caused by changing blood volume in the retina. Waveform and pulse parameters like amplitude and rise time can be measured in any selected areas within the retinal image. Fixation pattern ΔY(ΔX) can be assessed from eye movements during video acquisition. The eye movements ΔX[t], ΔY[t] are derived from image registration results with high temporal (40 ms) and spatial (1,86 arcmin) resolution. Parameters of pulsatile reflection changes and fixation pattern can be affected in beginning glaucoma and the method described here may support early detection of glaucoma and other eye disease.

Diuretic renography in evaluating dilated upper urinary tract in children

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ireton, R.C.; Parker, R.M.; Hayden, P.

1987-02-01

The diuretic renogram provides a previously unavailable noninvasive method for assessing and following urinary tract dilation of diverse cause, and defining true obstruction in children. Technetium-99m-DTPA (diethylenetriaminepentaacetic acid) is injected intravenously and a posteriorly placed gamma scintillation camera used to image the kidneys, ureters, and bladder. Furosemide is subsequently injected to stimulate a diuresis, and the washout pattern of isotope is monitored (time-activity histogram). Nonobstructive, obstructive, and poor renal function patterns were seen. Forty patients with varying degrees of hydroureteronephrosis were evaluated. Tracings were performed serially and compared with the clinical course in time, as well as with pressure flowmore » studies and operative findings. All patients with a nonobstructed diuretic renogram did well, except for 1 boy in whom ureteropelvic obstruction developed later. Difficulty in evaluating the obstructive renogram pattern occurred only in some children with severe (grade V) hydronephrosis. Further standardization of the diuretic renogram with regard to time of diuretic injection, state of patient hydration, and regions of imaging may improve diagnostic accuracy.« less

Aortic valve dysfunction and aortic dilation in adults with coarctation of the aorta.

PubMed

Clair, Mathieu; Fernandes, Susan M; Khairy, Paul; Graham, Dionne A; Krieger, Eric V; Opotowsky, Alexander R; Singh, Michael N; Colan, Steven D; Meijboom, Erik J; Landzberg, Michael J

2014-01-01

To determine the prevalence of aortic valve dysfunction, aortic dilation, and aortic valve and ascending aortic intervention in adults with coarctation of the aorta (CoA). Aortic valve dysfunction and aortic dilation are rare among children and adolescents with CoA. With longer follow-up, adults may be more likely to have progressive disease. We retrospectively reviewed all adults with CoA, repaired or unrepaired, seen at our center between 2004 and 2010. Two hundred sixteen adults (56.0% male) with CoA were identified. Median age at last evaluation was 28.3 (range 18.0 to 75.3) years. Bicuspid aortic valve (BAV) was present in 65.7%. At last follow-up, 3.2% had moderate or severe aortic stenosis, and 3.7% had moderate or severe aortic regurgitation. Dilation of the aortic root or ascending aorta was present in 28.0% and 41.6% of patients, respectively. Moderate or severe aortic root or ascending aortic dilation (z-score > 4) was present in 8.2% and 13.7%, respectively. Patients with BAV were more likely to have moderate or severe ascending aortic dilation compared with those without BAV (19.5% vs. 0%; P < 0.001). Age was associated with ascending aortic dilation (P = 0.04). At most recent follow-up, 5.6% had undergone aortic valve intervention, and 3.2% had aortic root or ascending aortic replacement. In adults with CoA, significant aortic valve dysfunction and interventions during early adulthood were uncommon. However, aortic dilation was prevalent, especially of the ascending aorta, in patients with BAV. © 2013 Wiley Periodicals, Inc.

Pravastatin and endothelium dependent vasomotion after coronary angioplasty: the PREFACE trial.

PubMed

Mulder, H J; Schalij, M J; Kauer, B; Visser, R F; van Dijkman, P R; Jukema, J W; Zwinderman, A H; Bruschke, A V

2001-11-01

To test the hypothesis that the 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitor pravastatin ameliorates endothelium mediated responses of dilated coronary segments: the PREFACE (pravastatin related effects following angioplasty on coronary endothelium) trial. A double blind, randomised, placebo controlled, multicentre study. Four hospitals in the Netherlands. 63 non-smoking, non-hypercholesterolaemic patients scheduled for elective balloon angioplasty (pravastatin 34, placebo 29). The effects of three months of pravastatin treatment (40 mg daily) on endothelium dependent vasomotor function were studied. Balloon angioplasty was undertaken one month after randomisation, and coronary vasomotor function tests using acetylcholine were performed two months after balloon angioplasty. The angiograms were analysed quantitatively. The efficacy measure was the acetylcholine induced change in mean arterial diameter, determined in the dilated segment and in an angiographically normal segment of an adjacent non-manipulated coronary artery. Increasing acetylcholine doses produced vasoconstriction in the dilated segments (p = 0.004) but not in the normal segments. Pravastatin did not affect the vascular response to acetylcholine in either the dilated segments (p = 0.09) or the non-dilated sites. Endothelium dependent vasomotion in normal segments was correlated with that in dilated segments (r = 0.47, p < 0.001). There were fewer procedure related events in the pravastatin group than in the placebo group (p < 0.05). Endothelium dependent vasomotion in normal segments is correlated with that in dilated segments. A significant beneficial effect of pravastatin on endothelial function could not be shown, but in the dilated segments there was a trend towards a beneficial treatment effect in the pravastatin group.

Exome Sequencing Establishes Diagnosis of Alström Syndrome in an Infant Presenting with Non-Syndromic Dilated Cardiomyopathy

PubMed Central

Long, Pamela A.; Evans, Jared M.; Olson, Timothy M.

2015-01-01

Idiopathic dilated cardiomyopathy is a heritable, genetically heterogeneous disorder characterized by progressive heart failure. Dilated cardiomyopathy typically exhibits autosomal dominant inheritance, yet frequently remains clinically silent until adulthood. We sought to discover the molecular basis of idiopathic, non-syndromic dilated cardiomyopathy in a one-month-old male presenting with severe heart failure. Previous comprehensive testing of blood, urine, and skin biopsy specimen was negative for metabolic, mitochondrial, storage, and infectious etiologies. Ophthalmologic examination was normal. Chromosomal microarray and commercial dilated cardiomyopathy gene panel testing failed to identify a causative mutation. Parental screening echocardiograms revealed no evidence of clinically silent dilated cardiomyopathy. Whole exome sequencing was carried out on the family trio on a research basis, filtering for rare, deleterious, recessive and de novo genetic variants. Pathogenic compound heterozygous truncating mutations were identified in ALMS1, diagnostic of Alström syndrome and prompting disclosure of genetic findings. Alström syndrome is a known cause for dilated cardiomyopathy in children yet delayed and mis-diagnosis are common owing to its rarity and age-dependent emergence of multisystem clinical manifestations. At six months of age the patient ultimately developed bilateral nystagmus and hyperopia, features characteristic of the syndrome. Early diagnosis is guiding clinical monitoring of other organ systems and allowing for presymptomatic intervention. Furthermore, recognition of recessive inheritance as the mechanism for sporadic disease has informed family planning. This case highlights a limitation of standard gene testing panels for pediatric dilated cardiomyopathy and exemplifies the potential for whole exome sequencing to solve a diagnostic dilemma and enable personalized care. PMID:25706677

Cricopharyngeal dilatation for the long-term treatment of dysphagia in oculopharyngeal muscular dystrophy.

PubMed

Manjaly, Joseph G; Vaughan-Shaw, Peter G; Dale, Oliver T; Tyler, Susan; Corlett, Jonathan C R; Frost, Roger A

2012-06-01

Oculopharyngeal muscular dystrophy (OPMD) is a rare autosomal dominant, progressive degenerative muscle disorder featuring dysphagia with limited therapeutic options. The aim of this study was to evaluate the safety and efficacy of repeated endoscopic dilatation for OPMD over a 15-year period. All patients seen at our Regional Swallowing Clinic with OPMD confirmed by genetic analysis were included. Cricopharyngeal dilatation was performed as an outpatient procedure using a wire-guided 18-mm (54 Fr) Savary-Gilliard bougie with the patient under sedation. Patients were offered repeat endoscopic dilatation when symptoms recurred. Symptom severity prior to initial dilatation and at follow-up was evaluated using the Sydney Swallow Questionnaire (SSQ). Nine patients (7 female, 2 male) were included for analysis. Median total treatment period was 13 years (range = 3-15), median number of dilatations per patient was 7.2 (range = 1-16), and median interval between treatments was 15 months (range = 4.5-45). All patients recorded sustained symptom improvement. Mean SSQ score (out of 1,700) was 1,108.11 (SD ± 272.85) prior to first dilatation and 297.78 (SD ± 189.14) at last follow-up, representing a 73% decrease (95% CI = 52-94) in degree of dysphagia symptoms (paired t-test, P = 0.0001). All mean scores for individual questions also showed significant improvement (P < 0.05). No adverse events were reported with all patients maintaining oral feeding at last follow-up. Repeated cricopharyngeal dilatation is a safe, effective, well-tolerated, and long-lasting treatment for dysphagia in OPMD.

Influence of complex interfacial rheology on the thermocapillary migration of a surfactant-laden droplet in Poiseuille flow

NASA Astrophysics Data System (ADS)

Das, Sayan; Chakraborty, Suman

2018-02-01

The effect of surface viscosity on the motion of a surfactant-laden droplet in the presence of a non-isothermal Poiseuille flow is studied, both analytically and numerically. The presence of bulk-insoluble surfactants along the droplet surface results in interfacial shear and dilatational viscosities. This, in turn, is responsible for the generation of surface-excess viscous stresses that obey the Boussinesq-Scriven constitutive law for constant values of surface shear and dilatational viscosities. The present study is primarily focused on finding out how this confluence can be used to modulate droplet dynamics in the presence of Marangoni stress induced by nonuniform distribution of surfactants and temperature along the droplet surface, by exploiting an intricate interplay of the respective forcing parameters influencing the interfacial stresses. Under the assumption of negligible fluid inertia and thermal convection, the steady-state migration velocity of a non-deformable spherical droplet, placed at the centerline of an imposed unbounded Poiseuille flow, is obtained for the limiting case when the surfactant transport along the interface is dominated by surface diffusion. Our analysis proves that the droplet migration velocity is unaffected by the shear viscosity whereas the dilatational viscosity has a significant effect on the same. The surface viscous effects always retard the migration of a surfactant-laden droplet when the temperature in the far-field increases in the direction of the imposed flow although the droplet always migrates towards the hotter region. On the contrary, if a large temperature gradient is applied in a direction opposite to that of the imposed flow, the direction of droplet migration gets reversed. However, for a sufficiently high value of dilatational surface viscosity, the direction of droplet migration reverses. For the limiting case in which the surfactant transport along the droplet surface is dominated by surface convection, on the other hand, surface viscosities do not have any effect on the motion of the droplet. These results are likely to have far-reaching consequences in designing an optimal migration path in droplet-based microfluidic technology.

Influence of affective significance on different levels of processing using pupil dilation in an analogical reasoning task.

PubMed

Prehn, Kristin; Heekeren, Hauke R; van der Meer, Elke

2011-02-01

The present study investigates the interaction of cognition and emotion in decision making, using an analogical reasoning task. In this task, two word pairs were presented simultaneously. Each word pair could be characterized by an associative conceptual relation (object, actor, or location relation) as well as an emotional relation (negative, neutral, or positive valence). Both types of relations were equally task-relevant: Participants had to identify both types of relations, to compare them, and to decide whether or not the word pairs were analogous, i.e., corresponding in both conceptual and emotional relations. Behavioral data showed that emotional relations were identified preferentially and faster than conceptual relations. Pupil dilations reflected the descending difficulty of the conditions and were greatest in amplitude when both conceptual and emotional correspondence was shown, intermediate when only one type of relation (either the emotional or the conceptual) corresponded, and least when neither correspondence existed. Additionally, a negative valence of the word material slowed down response times and increased pupil dilation relative to positive and neutral items. In summary, pupil and response time data together support recent (neurobiological) models concerning the interaction of emotion and cognition by showing that affective significance leads to a processing advantage at a cognitively lower level of information processing (here, identification or retrieval of relations from long-term memory) but can also distract people from higher level cognitive processes (here, from the controlled comparison of retrieved relations). Copyright © 2010 Elsevier B.V. All rights reserved.

Emotional arousal predicts intertemporal choice

PubMed Central

Lempert, Karolina M.; Johnson, Eli; Phelps, Elizabeth A.

2016-01-01

People generally prefer immediate rewards to rewards received after a delay, often even when the delayed reward is larger. This phenomenon is known as temporal discounting. It has been suggested that preferences for immediate rewards may be due to their being more concrete than delayed rewards. This concreteness may evoke an enhanced emotional response. Indeed, manipulating the representation of a future reward to make it more concrete has been shown to heighten the reward’s subjective emotional intensity, making people more likely to choose it. Here we use an objective measure of arousal – pupil dilation – to investigate if emotional arousal mediates the influence of delayed reward concreteness on choice. We recorded pupil dilation responses while participants made choices between immediate and delayed rewards. We manipulated concreteness through time interval framing: delayed rewards were presented either with the date on which they would be received (e.g., “$30, May 3”; DATE condition, more concrete) or in terms of delay to receipt (e.g., “$30, 7 days; DAYS condition, less concrete). Contrary to prior work, participants were not overall more patient in the DATE condition. However, there was individual variability in response to time framing, and this variability was predicted by differences in pupil dilation between conditions. Emotional arousal increased as the subjective value of delayed rewards increased, and predicted choice of the delayed reward on each trial. This study advances our understanding of the role of emotion in temporal discounting. PMID:26882337

Safety and efficacy of silodosin and tadalafil in ease of negotiation of large ureteroscope in the management of ureteral stone: A prosective randomized trial.

PubMed

Bhattar, Rohit; Jain, Vipin; Tomar, Vinay; Yadav, Sher Singh

2017-12-01

To evaluate the safety and efficacy of silodosin and tadalafil in ease of negotiation of large size ureteroscope (8/9.8 Fr) in the management of ureteral stone. Between June 2015 and May 2016, 86 patients presented with ureteral stone of size 6-15 mm were on consent randomly assigned to 1 of 3 outpatient treatment arms: silodosin (Group A), tadalafil (Group B), and placebo (Group C). After two weeks of therapy 67 patients underwent ureteroscopy, and ureteral orifice configuration, ureteroscopic negotiation, ureteral dilatation, operating time, procedural complication and drug related side effects were noted in each group. Ureteral negotiation was significantly better in Groups A (73.9%) and B (69.6%) as compared to Group C (38.1%) (p<0.01). Statistically significant difference was noted in the requirement for dilatation in Group C (71.4%) as compared to Groups A (26.1%) and B (39.1%) (p<0.01). Ureteral orifice was found to be more dilated in Groups A (69.6%) and B (60.9%) as compared to Group C (28.6%). Mean operating time was statistically lower in Groups A (35.2 min) and B (34.91 min) as compared to Group C (41.14 min) (p<0.01). Both silodosin and tadalafil not only relax ureteral smooth muscle but also help in forward propagation of large size ureteroscope (8/9.8 Fr) without any significant risk of adverse events.

Laparoscopic Heller myotomy and fundoplication in patients with Chagas' disease achalasia and massively dilated esophagus.

PubMed

Pantanali, Carlos A R; Herbella, Fernando A M; Henry, Maria A; Mattos Farah, Jose Francisco; Patti, Marco G

2013-01-01

Laparoscopic Heller myotomy and fundoplication is considered today the treatment of choice for achalasia. The optimal treatment for end-stage achalasia with esophageal dilation is still controversial. This multicenter and retrospective study aims to evaluate the outcome of laparoscopic Heller myotomy in patients with a massively dilated esophagus. Eleven patients (mean age, 56 years; 6 men) with massively dilated esophagus (esophageal diameter greater than 10 cm) underwent a laparoscopic Heller myotomy and anterior fundoplication between 2000 and 2009 at three different institutions. Preoperative workup included upper endoscopy, esophagram, and esophageal manometry in all patients. Average follow-up was 31.5 months (range, 3 to 60 months). Two patients (18%) had severe dysphagia, four patients (36%) had mild and occasional dysphagia to solid food, and five patients (45%) were asymptomatic. All patients gained or kept body weight, except for the two patients with severe dysphagia. Of the two patients with severe dysphagia, one underwent esophageal dilatation and the other a laparoscopic esophagectomy. They are both doing well. Heller myotomy relieves dysphagia in the majority of patients even when the esophagus is massively dilated.

Canine candidate genes for dilated cardiomyopathy: annotation of and polymorphic markers for 14 genes

PubMed Central

Wiersma, Anje C; Leegwater, Peter AJ; van Oost, Bernard A; Ollier, William E; Dukes-McEwan, Joanna

2007-01-01

Background Dilated cardiomyopathy is a myocardial disease occurring in humans and domestic animals and is characterized by dilatation of the left ventricle, reduced systolic function and increased sphericity of the left ventricle. Dilated cardiomyopathy has been observed in several, mostly large and giant, dog breeds, such as the Dobermann and the Great Dane. A number of genes have been identified, which are associated with dilated cardiomyopathy in the human, mouse and hamster. These genes mainly encode structural proteins of the cardiac myocyte. Results We present the annotation of, and marker development for, 14 of these genes of the dog genome, i.e. α-cardiac actin, caveolin 1, cysteine-rich protein 3, desmin, lamin A/C, LIM-domain binding factor 3, myosin heavy polypeptide 7, phospholamban, sarcoglycan δ, titin cap, α-tropomyosin, troponin I, troponin T and vinculin. A total of 33 Single Nucleotide Polymorphisms were identified for these canine genes and 11 polymorphic microsatellite repeats were developed. Conclusion The presented polymorphisms provide a tool to investigate the role of the corresponding genes in canine Dilated Cardiomyopathy by linkage analysis or association studies. PMID:17949487

Canine candidate genes for dilated cardiomyopathy: annotation of and polymorphic markers for 14 genes.

PubMed

Wiersma, Anje C; Leegwater, Peter Aj; van Oost, Bernard A; Ollier, William E; Dukes-McEwan, Joanna

2007-10-19

Dilated cardiomyopathy is a myocardial disease occurring in humans and domestic animals and is characterized by dilatation of the left ventricle, reduced systolic function and increased sphericity of the left ventricle. Dilated cardiomyopathy has been observed in several, mostly large and giant, dog breeds, such as the Dobermann and the Great Dane. A number of genes have been identified, which are associated with dilated cardiomyopathy in the human, mouse and hamster. These genes mainly encode structural proteins of the cardiac myocyte. We present the annotation of, and marker development for, 14 of these genes of the dog genome, i.e. alpha-cardiac actin, caveolin 1, cysteine-rich protein 3, desmin, lamin A/C, LIM-domain binding factor 3, myosin heavy polypeptide 7, phospholamban, sarcoglycan delta, titin cap, alpha-tropomyosin, troponin I, troponin T and vinculin. A total of 33 Single Nucleotide Polymorphisms were identified for these canine genes and 11 polymorphic microsatellite repeats were developed. The presented polymorphisms provide a tool to investigate the role of the corresponding genes in canine Dilated Cardiomyopathy by linkage analysis or association studies.

Preoperative ripening of the cervix before operative hysteroscopy.

PubMed

Al-Fozan, Haya; Firwana, Belal; Al Kadri, Hanan; Hassan, Samar; Tulandi, Togas

2015-04-23

Hysteroscopy is an operation in which the gynaecologist examines the uterine cavity using a small telescopic instrument (hysteroscope) inserted via the vagina and the cervix. Almost 50% of hysteroscopic complications are related to difficulty with cervical entry. Potential complications include cervical tears, creation of a false passage, perforation, bleeding, or simply difficulty in entering the internal os (between the cervix and the uterus) with the hysteroscope. These complications may possibly be reduced with adequate preparation of the cervix (cervical ripening) prior to hysteroscopy. Cervical ripening agents include oral or vaginal prostaglandin, which can be synthetic (e.g misoprostol) or natural (e.g. dinoprostone) and vaginal osmotic dilators, which can be naturally occurring (e.g. laminaria) or synthetic. To determine whether preoperative cervical preparation facilitates cervical dilatation and reduces the complications of operative hysteroscopy in women undergoing the procedure for any condition. In August 2014 we searched sources including the Menstrual Disorders and Subfertility Group (MDSG) Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, CINAHL, ClinicalTrials.gov and reference lists of relevant articles. We searched for published and unpublished studies in any language. Two review authors independently selected randomised controlled trials (RCTs) of cervical ripening agents used before operative hysteroscopy in pre- and postmenopausal women. Cervical ripening agents could be compared to each other, placebo or no treatment. Data extraction and quality assessment were conducted independently by two review authors. The primary review outcomes were effectiveness of cervical dilatation (defined as the proportion of women requiring mechanical cervical dilatation) and intraoperative complications. Secondary outcomes were mean time required to dilate the cervix, preoperative pain, cervical width, abandonment of the procedure, side effects of dilating agents and duration of surgery. We calculated odds ratios (ORs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, with 95% confidence intervals ( CIs). Data were statistically pooled where appropriate. Heterogeneity was assessed using the I(2) statistic. The overall quality of the evidence was assessed using GRADE methods. Nineteen RCTs with a total of 1870 participants were included. They compared misoprostol with no treatment or placebo, dinoprostone or osmotic dilators.Misoprostol was more effective for cervical dilatation than placebo or no intervention, with fewer women requiring mechanical dilatation (OR 0.08, 95% CI 0.04 to 0.16, five RCTs, 441 participants, I(2)=0%, moderate quality evidence). This suggests that in a population in which 80% of women undergoing hysteroscopy require mechanical dilatation without use of preoperative ripening agents, use of misoprostol will reduce the need for mechanical dilatation to between 14% and 39%. Misoprostol was associated with fewer intraoperative complications (OR 0.37, 95% CI 0.18 to 0.77, 12 RCTs, 901 participants, I(2)=0%, moderate quality evidence). This suggests that in a population in which 3% of women undergoing hysteroscopy experience intraoperative complications without use of preoperative ripening agents, use of misoprostol will reduce the risk of complications to 2% or less.When specific complications were considered, the misoprostol group had a lower rate of cervical laceration or tearing (OR 0.25, 95% CI 0.11 to 0.57, nine RCTS, 669 women, I(2)=0%, moderate quality evidence) or false track formation (OR 0.34, 95% CI 0.12 to 0.97, seven RCTs, 560 participants, I(2)=0%, moderate quality evidence). There was no evidence of a difference between the groups in rates of uterine perforation (0.42, 95% CI 0.13 to 1.38, seven RCTs, 455 participants, I(2)=0%, low quality evidence) or uterine bleeding (OR 0.51, 95% CI 0.10 to 2.49, four RCTs, 340 participants, I(2)=0%, low quality evidence). Some treatment side effects (mild abdominal pain, vaginal bleeding, and increased body temperature) were more common in the misoprostol group.Compared with dinoprostone, misoprostol was associated with more effective cervical dilatation, with fewer women requiring mechanical dilatation (OR 0.58; 95% CI 0.34 to 0.98; one RCT, 310 participants, low quality evidence) and with fewer intraoperative complications (OR 0.32; 95% CI 0.12 to 0.83, one RCT, 310 participants, low quality evidence). However treatment side effects were more common in the misoprostol arm.Compared to osmotic dilatation (laminaria), misoprostol was associated with less effective cervical dilatation, with more women in the misoprostol group requiring mechanical dilatation (OR 5.96, 95% CI 2.61 to 13.59, one RCT, 110 participants, low quality evidence). There was no evidence of a difference between misoprostol and osmotic dilators in intraoperative complication rates (OR 5.14, 95% CI 0.24 to 109.01, three RCTs, 354 participants, low quality evidence), with only two events reported altogether.The overall quality of the evidence ranged from low to moderate. The main limitations in the evidence were imprecision and poor reporting of study methods. There is moderate quality evidence that use of misoprostol for preoperative ripening of the cervix before operative hysteroscopy is more effective than placebo or no treatment and is associated with fewer intraoperative complications such as lacerations and false tracks. However misoprostol is associated with more side effects, including preoperative pain and vaginal bleeding. There is low quality evidence to suggest that misoprostol has fewer intraoperative complications and is more effective than dinoprostone.There is also low quality evidence to suggest that laminaria may be more effective than misoprostol, with uncertain effects for complication rates. However the possible benefits of laminaria need to be weighed against the inconvenience of its insertion and retention for one to two days.

The Phenylephrine Test Revisited.

PubMed

Barsegian, Arpine; Botwinick, Adam; Reddy, Harsha S

To characterize the phenylephrine test in ptotic patients to help clinicians perform the test more efficiently. Adults with involutional ptosis (n = 24, 30 eyes) were assessed with digital photographs for response to topical 2.5% phenylephrine drop instillation. Patient characteristics (age, gender, iris color, dermatochalasis, brow ptosis, and baseline marginal reflex distance-1 [MRD-1] height) were recorded. From the photographs, change in (MRD-1), presence of conjunctival blanching, pupillary dilation, and Hering effect were recorded at specified time intervals, 1 minute to 1 hour after drop placement. Correlations between patient characteristics and measured outcomes were evaluated using analysis of variance, Pearson coefficient, or chi-square tests. The authors found that 73% of eyes had eyelid elevation with phenylephrine. Of these, 50% reached maximal eyelid elevation by 5 minutes, and 86% by 10 minutes after drop placement, but 14% did not reach maximal MRD-1 until 30 minutes. There is a negative correlation between the maximum MRD-1 and the baseline MRD-1 eyelid height (r = -0.5330, p < 0.01). There is no significant relationship between time to pupillary dilation with either time to max eyelid elevation or max eyelid elevation. No patient characteristic studied affected the likelihood of eyelid response to phenylephrine or presence of Hering effect. Although most ptotic eyelids demonstrate a response to 2.5% phenylephrine within 10 minutes, there is a subset of patients that respond much later. More ptotic eyelids had greater eyelid elevation with phenylephrine. Pupillary dilation and conjunctival blanching are neither predictive of nor temporally associated with eyelid height elevation. The authors did not identify any patient factors (e.g., dermatochalasis, brow ptosis) that can predict the likelihood of response to phenylephrine.

Urethroplasty: a geographic disparity in care.

PubMed

Burks, Frank N; Salmon, Scott A; Smith, Aaron C; Santucci, Richard A

2012-06-01

Urethroplasty is the gold standard for urethral strictures but its geographic prevalence throughout the United States is unknown. We analyzed where and how often urethroplasty was being performed in the United States compared to other treatment modalities for urethral stricture. De-identified case logs from the American Board of Urology were collected from certifying/recertifying urologists from 2004 to 2009. Results were categorized by ZIP codes to determine the geographic distribution. Case logs from 3,877 urologists (2,533 recertifying and 1,344 certifying) were reviewed including 1,836 urethroplasties, 13,080 urethrotomies and 19,564 urethral dilations. The proportion of urethroplasty varied widely among states (range 0% to 17%). The ratio of urethroplasty-to-urethrotomy/dilation also varied widely from state to state, but overall 1 urethroplasty was performed for every 17 urethrotomies or dilations performed. Certifying urologists were 3 times as likely to perform urethroplasty as recertifying urologists (12% vs 4%, respectively, p<0.05). Urethroplasties were performed more commonly in states with residency programs (mean 5% vs 3%). Some states reported no urethroplasties during the observation period (Vermont, North Dakota, South Dakota, Maine and West Virginia). To our knowledge this is the first report on the geographic distribution of urethroplasty for urethral stricture disease. There are large variations in the rates of urethroplasty performed throughout the United States, indicating a disparity of care, especially for those regions in which few or no urethroplasties were reported. This disparity may decrease with time as younger certifying urologists are performing 3 times as many urethroplasties as older recertifying urologists. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Managing many patients with a urethral stricture: a cost-benefit analysis of treatment options.

PubMed

Ogbonna, B C

1998-05-01

To report a management method in a community where there are many patients with urethral stricture and where the short-term goal of providing some treatment to most may override the sometimes conflicting long-term aim of minimizing recurrence rates. Over a 3-year period, using optical urethrotomy in 76 patients followed by intermittent self-dilatation (ISD) in 29, urethroplasty in 28 and dilatation in three, 92 of 134 patients with a urethral stricture were treated and the outcome compared. The overall recurrence rate was 22%; a combination of urethrotomy plus ISD had a recurrence rate of 17% and gave a mean duration of follow-up without recurrence similar to that after urethroplasty. ISD significantly increased both the time before recurrence and the duration of follow-up without recurrence after urethrotomy. In addition to providing lasting treatment to many patients, urethrotomy was also 10 times cheaper, 10 times faster to perform and offered the surgeon better protection from infection with human immunodeficiency virus than did urethroplasty. Because wrongly selecting urethrotomy (resulting in a failed procedure) wastes valuable operating time and resources, the pre-operative recognition of strictures unsuitable for urethrotomy and their treatment by urethroplasty is important for overall efficiency.

Pubertal changes in emotional information processing: pupillary, behavioral, and subjective evidence during emotional word identification.

PubMed

Silk, Jennifer S; Siegle, Greg J; Whalen, Diana J; Ostapenko, Laura J; Ladouceur, Cecile D; Dahl, Ronald E

2009-01-01

This study investigated pupillary and behavioral responses to an emotional word valence identification paradigm among 32 pre-/early pubertal and 34 mid-/late pubertal typically developing children and adolescents. Participants were asked to identify the valence of positive, negative, and neutral words while pupil dilation was assessed using an eyetracker. Mid-/late pubertal children showed greater peak pupillary reactivity to words presented during the emotional word identification task than pre-/early pubertal children, regardless of word valence. Mid-/late pubertal children also showed smaller sustained pupil dilation than pre-/early pubertal children after the word was no longer on screen. These findings were replicated controlling for participants' age. In addition, mid-/late pubertal children had faster reaction times to all words, and rated themselves as more emotional during their laboratory visit compared to pre-/early pubertal children. Greater recall of emotional words following the task was associated with mid-/late pubertal status, and greater recall of emotional words was also associated with higher peak pupil dilation. These results provide physiological, behavioral, and subjective evidence consistent with a model of puberty-specific changes in neurobehavioral systems underpinning emotional reactivity.

Pubertal Changes in Emotional Information Processing: Pupillary, Behavioral, and Subjective Evidence during Emotional Word Identification

PubMed Central

Silk, Jennifer S.; Siegle, Greg J.; Whalen, Diana J.; Ostapenko, Laura J.; Ladouceur, Cecile D.; Dahl, Ronald E.

2008-01-01

This study investigated pupillary and behavioral responses to an emotional word valence identification paradigm among 32 pre/early and 34 mid/late pubertal typically developing children and adolescents. Participants were asked to identify the valence of positive, negative, and neutral words while pupil dilation was assessed using an eye-tracker. Mid-to-late pubertal children showed greater peak pupillary reactivity to words presented during the emotional word identification task than pre-to-early pubertal children, regardless of word valence. Mid-to-late pubertal children also showed smaller sustained pupil dilation than pre-to-early pubertal children after the word was no longer on screen. These findings were replicated controlling for participants’ age. Additionally, mid-to-late pubertal children had faster reaction times to all words, and rated themselves as more emotional during their laboratory visit compared to pre-to-early pubertal children. Greater recall of emotional words following the task was associated with mid-to-late pubertal status, and greater recall of emotional words was also associated with higher peak pupil dilation. These results provide physiological, behavioral, and subjective evidence consistent with a model of puberty-specific changes in neurobehavioral systems underpinning emotional reactivity. PMID:19144220

Optical properties of the mouse eye

PubMed Central

Geng, Ying; Schery, Lee Anne; Sharma, Robin; Dubra, Alfredo; Ahmad, Kamran; Libby, Richard T.; Williams, David R.

2011-01-01

The Shack-Hartmann wavefront sensor (SHWS) spots upon which ocular aberration measurements depend have poor quality in mice due to light reflected from multiple retinal layers. We have designed and implemented a SHWS that can favor light from a specific retinal layer and measured monochromatic aberrations in 20 eyes from 10 anesthetized C57BL/6J mice. Using this instrument, we show that mice are myopic, not hyperopic as is frequently reported. We have also measured longitudinal chromatic aberration (LCA) of the mouse eye and found that it follows predictions of the water-filled schematic mouse eye. Results indicate that the optical quality of the mouse eye assessed by measurement of its aberrations is remarkably good, better for retinal imaging than the human eye. The dilated mouse eye has a much larger numerical aperture (NA) than that of the dilated human eye (0.5 NA vs. 0.2 NA), but it has a similar amount of root mean square (RMS) higher order aberrations compared to the dilated human eye. These measurements predict that adaptive optics based on this method of wavefront sensing will provide improvements in retinal image quality and potentially two times higher lateral resolution than that in the human eye. PMID:21483598

Surgical management of reflux strictures of the esophagus in childhood.

PubMed Central

O'Neill, J A; Betts, J; Ziegler, M M; Schnaufer, L; Bishop, H C; Templeton, J M

1982-01-01

The etiology of gastroesophageal reflux (GER) in infancy is related to developmental factors, and there is a high incidence of associated conditions such as neurologic syndromes and esophageal atresia (60%). This is different from the situation in adults. Experience with 18 consecutive children with peptic esophageal strictures is reviewed to determine if conservative surgical management is effective. Eighteen children 14 months to 13 years (mean 6.3 years) of age took an average of 3.5 years from the time of onset of symptoms of GER to develop tight strictures diagnosed by esophagography and esophagoscopy. The incidence of stricture in patients with GER was approximately 15%. Preoperative dilation or direct surgical management prior to correction of reflux is ineffective. All 18 children were managed by intraoperative dilatation, Nissen fundoplication, and guided dilatation after operation. More aggressive surgical procedures were not required nor were associated operations such as pyloroplasty; they are rarely necessary. An average three-year follow-up indicates that this conservative surgical approach is effective in the management of peptic esophageal strictures in childhood with relief of symptoms and gratifying improvement in growth. Images Fig. 3. Fig. 4. Fig. 5. PMID:7125730

Prevalence of pharyngeal and esophageal stenosis following radiation for head and neck cancer.

PubMed

Nguyen, Nam P; Smith, Herbert J; Moltz, Candace C; Frank, Cheryl; Millar, Carrie; Dutta, Suresh; Lee, Howard; North, Debra; Karlsson, Ulf; Vos, Paul; Nguyen, Ly M; Sallah, Sabah

2008-04-01

To evaluate the risk and outcome of pharyngoesophageal stenosis in patients who complained of dysphagia following radiation for head and neck cancer. Retrospective study. Veterans Administration hospital. Patients who complained of persistent dysphagia following radiation alone or combined with surgery or chemotherapy for head and neck cancer. Patients were selected if they were cancer free at the time of the swallowing study. All patients had modified barium swallow (MBS) and an endoscopic examination for initial evaluation of their dysphagia. Traditional barium swallow was requested when there was a suspicion of pharyngoesophageal stenosis on MBS. Two hundred twenty-two patients underwent MBS for evaluation of dysphagia posttreatment. Traditional barium swallow confirmed the diagnosis of pharyngeal (n = 2) or esophageal (n = 14) stenosis in 16 patients. Eight patients had esophageal stenosis on endoscopic examination. All patients underwent dilatation for relief of their dysphagia. The number of dilatations performed was, respectively, one in 12 patients, two in 4 patients, three in 3 patients, four in 3 patients, five in one patient, and six in one patient. Pharyngeal and/or cervical esophageal stenosis may be the cause of dysphagia following radiation for head and neck cancer. Esophageal dilatations often offer temporary relief of the dysphagia.

Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

PubMed

Crystal, Matthew A; Morgan, Gareth J; Danon, Saar; Gray, Robert G; Gruenstein, Daniel H; Gordon, Brent M; Goldstein, Bryan H

2018-01-01

Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to better understand the response to attempted TSF for newly developed stents as well as those currently in use.

Prognostic Value of Ultrasound Grading Systems in Prenatally Diagnosed Unilateral Urinary Tract Dilatation.

PubMed

Scalabre, Aurélien; Demède, Delphine; Gaillard, Ségolène; Pracros, Jean-Pierre; Mouriquand, Pierre; Mure, Pierre-Yves

2017-04-01

We compared the prognostic value of anteroposterior intrasinus diameter of the renal pelvis, urinary tract dilatation and the Society for Fetal Urology grading system in children with prenatally diagnosed unilateral urinary tract dilatation. All newborns with prenatally diagnosed unilateral urinary tract dilatation, normal bladder and anteroposterior intrasinus diameter 10 mm or greater on the first postnatal ultrasonography were prospectively enrolled from January 2011 to February 2015. Indications for surgery were recurrent febrile urinary tract infections and/or decrease of relative renal function more than 10% on serial isotope studies and/or increasing anteroposterior intrasinus diameter greater than 20% on serial ultrasounds. Sensitivity, specificity and ROC curves were calculated to evaluate the accuracy of anteroposterior intrasinus diameter, urinary tract dilatation and Society for Fetal Urology grading system in determining which children would need surgery within 24 months. A total of 57 males and 13 females were included. Of the patients 33 required surgery at a median age of 5 months (IQR 3.8 to 6.4). Urinary tract dilatation remained stable in 14 cases and decreased in 23 with a median followup of 42 months (IQR 25 to 67). Anteroposterior intrasinus diameter, urinary tract dilatation and Society for Fetal Urology scores were all correlated with the need for surgery. Anteroposterior intrasinus diameter with a threshold of 20 mm had the best prognostic value, with a sensitivity of 81.8% and a specificity of 91.7%. Our study confirms that the prognostic value was comparable between anteroposterior intrasinus diameter of the renal pelvis, urinary tract dilatation and Society for Fetal Urology grading system in newborns with prenatally diagnosed unilateral urinary tract dilatation. Anteroposterior intrasinus diameter and abnormal parenchymal thickness are the most important ultrasound criteria to identify children at risk for requiring surgery. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Trends in gestational age at time of surgical abortion for fetal aneuploidy and structural abnormalities.

PubMed

Davis, Anne R; Horvath, Sarah K; Castaño, Paula M

2017-03-01

Screening for fetal aneuploidy has evolved over the past 2 decades. Whether these advances impact gestational age at abortion has received little study. We sought to describe trends in the gestational age at the time of abortion by fetal diagnosis over an 11-year study period. We hypothesized that gestational age at time of abortion would decrease for fetal aneuploidy but remain unchanged for structural abnormalities. We conducted a retrospective case series of all women undergoing surgical abortion for fetal aneuploidy or structural abnormalities up to 24 weeks' gestation from 2004 through 2014 in a hospital operating room setting at a single, urban medical center. We excluded labor induction abortions (<1% of abortions at our medical center) and suction aspirations performed in the office practice. We performed suction aspiration up to 14 weeks and dilation and evacuation after that gestational age. We describe the median gestational age at abortion by fetal indication and year. For women undergoing abortion for fetal aneuploidy (n = 392), the median gestational age at time of abortion decreased from 19.0 weeks (interquartile range 18.0-21.0) in 2004 to 14.0 weeks (interquartile range 13.0-17.0) in 2014 (Kruskal-Wallis P < .0001). For women undergoing abortion for fetal structural abnormalities (n = 586), the median gestational age was ≥20 weeks for each year during the study interval (P = .1). As gestational age decreased in the fetal aneuploidy group, fewer women underwent dilation and evacuation and more became eligible for suction aspiration (<14 weeks). In 2004, >90% of women underwent dilation and evacuation for either indication. By 2014, 31% of women with fetal aneuploidy were eligible for suction aspiration compared to 11% of those with structural anomalies. Gestational age at the time of abortion for fetal aneuploidy decreased substantially from 2004 through 2014; earlier abortion is safer for women. In contrast, women seeking abortion for fetal structural abnormalities did not experience a change in timing. Legislation restricting gestational age at the time of abortion could disproportionately affect women with fetal structural abnormalities. Copyright © 2016 Elsevier Inc. All rights reserved.

Real-time adjustment of ventricular restraint therapy in heart failure.

PubMed

Ghanta, Ravi K; Lee, Lawrence S; Umakanthan, Ramanan; Laurence, Rita G; Fox, John A; Bolman, Ralph Morton; Cohn, Lawrence H; Chen, Frederick Y

2008-12-01

Current ventricular restraint devices do not allow for either the measurement or adjustment of ventricular restraint level. Periodic adjustment of restraint level post-device implantation may improve therapeutic efficacy. We evaluated the feasibility of an adjustable quantitative ventricular restraint (QVR) technique utilizing a fluid-filled polyurethane epicardial balloon to measure and adjust restraint level post-implantation guided by physiologic parameters. QVR balloons were implanted in nine ovine with post-infarction dilated heart failure. Restraint level was defined by the maximum restraint pressure applied by the balloon to the epicardium at end-diastole. An access line connected the balloon lumen to a subcutaneous portacath to allow percutaneous access. Restraint level was adjusted while left ventricular (LV) end-diastolic volume (EDV) and cardiac output was assessed with simultaneous transthoracic echocardiography. All nine ovine successfully underwent QVR balloon implantation. Post-implantation, restraint level could be measured percutaneously in real-time and dynamically adjusted by instillation and withdrawal of fluid from the balloon lumen. Using simultaneous echocardiography, restraint level could be adjusted based on LV EDV and cardiac output. After QVR therapy for 21 days, LV EDV decreased from 133+/-15 ml to 113+/-17 ml (p<0.05). QVR permits real-time measurement and physiologic adjustment of ventricular restraint therapy after device implantation.

[Successful endoscopic dilatation of a stenosis in relation to an ileorectal anastomosis by acute ileus].

PubMed

Kjærgaard, Jane Christensen; Hendel, Jakob; Gügenur, Ismail

2014-02-17

Endoscopic dilatation is a treatment option for patients with Crohns disease suffering from stenosis in relation to an ileorectal anastomosis. We present a case of a patient with Crohns disease who was admitted with acute obstructive symptoms due to a stensosis of the ileorectal anastomosis. The patient was septic. We performed a successful endoscopic dilatation in the acute phase and the patient was discharged few days after an uneventful recovery. Endoscopic dilatation of an ileorectal anastomsis in patients with Crohns disease is a treatment option in the acute setting when performed by experienced endoscopists.

Preoperative thoracic radiographic findings in dogs presenting for gastric dilatation-volvulus (2000-2010): 101 cases.

PubMed

Green, Jaime L; Cimino Brown, Dorothy; Agnello, Kimberly A

2012-10-01

To identify the incidence of clinically significant findings on preoperative thoracic radiographs in dogs with gastric dilatation-volvulus (GDV) and to determine if those findings are associated with survival. Retrospective study from 2000 to 2010. Urban university small animal teaching hospital. One hundred and one dogs diagnosed with GDV that had thoracic radiographs obtained preoperatively, and medical records available with the following information available: signalment, time of presentation, respiratory status, plasma lactate, presence of cardiac arrhythmias, reason for thoracic radiographs, radiographic findings, and outcome. None. Findings on preoperative thoracic radiographs included small vena cava (40%), esophageal dilation (39%), microcardia (34%), aspiration pneumonia (14%), cardiomegaly (5%), pulmonary nodule (4%), pulmonary edema (2%), sternal lymphadenopathy (1%), and pulmonary bullae (1%). Eighty-four percent of dogs (85 out of 101) survived to discharge. Dogs without cardiomegaly on presenting thoracic radiographs had a 10.2 greater odds of surviving to discharge. The most common findings on preoperative thoracic radiographs include esophageal dilation, microcardia, and a small vena cava while the incidence of pulmonary nodules was low. A negative association between survival and presence of cardiomegaly on preoperative thoracic radiographs in dogs with GDV supports the need to obtain these images for prognostic information in spite of the emergency surgical nature of the GDV. The main limitations of this study include the possibilities of type I and type II errors, the retrospective nature of the study, and the lack of well-defined criteria for obtaining thoracic radiographs. © Veterinary Emergency and Critical Care Society 2012.

Laparoscopic Heller myotomy provides durable relief from achalasia and salvages failures after botox or dilation.

PubMed

Rosemurgy, Alexander; Villadolid, Desiree; Thometz, Donald; Kalipersad, Candice; Rakita, Steven; Albrink, Michael; Johnson, Milton; Boyce, Worth

2005-05-01

To report outcome after laparoscopic Heller myotomy in a large number of patients. Laparoscopic Heller myotomy has been undertaken for over a decade, but most studies involve small numbers of patients with limited follow-up. Since 1992, 262 patients have undergone laparoscopic Heller myotomy and been prospectively followed. Concomitant fundoplication was undertaken for a patulous hiatus or large hiatal hernia or to buttress the repair of an esophagotomy until recently when it became routinely applied. With mean follow-up at 32 months, symptoms were scored by patients on a Likert scale (frequency: 0 = Never to 10 = Every time I eat/always; severity: 0 = Not bothersome to 10 = Very bothersome). Before myotomy, 79% received Botox or bag dilation: 52% had Botox, 59% underwent dilation, and 36% had both. Inadvertent esophagotomy occurred in 5%. Concomitant diverticulectomy was undertaken in 4%, and fundoplication was undertaken in 30%. Complications were infrequent. Median length of stay was 1 day. After myotomy, the frequency and severity of symptoms of achalasia and reflux significantly decreased. Eighty-eight percent of patients felt their symptoms were greatly improved or resolved, and 90% felt their outcome was satisfying or better. Ninety-three percent felt they would undergo myotomy again, if necessary. Laparoscopic Heller myotomy can safely and durably relieve symptoms of dysphagia while also reducing symptoms of reflux. Length of stay is short and patient satisfaction is very high with extended follow-up. Laparoscopic Heller myotomy is strongly encouraged for patients with symptomatic achalasia and is efficacious even after failures of dilation and/or Botox therapy.

3D MR ventricle segmentation in pre-term infants with post-hemorrhagic ventricle dilation

NASA Astrophysics Data System (ADS)

Qiu, Wu; Yuan, Jing; Kishimoto, Jessica; Chen, Yimin; de Ribaupierre, Sandrine; Chiu, Bernard; Fenster, Aaron

2015-03-01

Intraventricular hemorrhage (IVH) or bleed within the brain is a common condition among pre-term infants that occurs in very low birth weight preterm neonates. The prognosis is further worsened by the development of progressive ventricular dilatation, i.e., post-hemorrhagic ventricle dilation (PHVD), which occurs in 10-30% of IVH patients. In practice, predicting PHVD accurately and determining if that specific patient with ventricular dilatation requires the ability to measure accurately ventricular volume. While monitoring of PHVD in infants is typically done by repeated US and not MRI, once the patient has been treated, the follow-up over the lifetime of the patient is done by MRI. While manual segmentation is still seen as a gold standard, it is extremely time consuming, and therefore not feasible in a clinical context, and it also has a large inter- and intra-observer variability. This paper proposes a segmentation algorithm to extract the cerebral ventricles from 3D T1- weighted MR images of pre-term infants with PHVD. The proposed segmentation algorithm makes use of the convex optimization technique combined with the learned priors of image intensities and label probabilistic map, which is built from a multi-atlas registration scheme. The leave-one-out cross validation using 7 PHVD patient T1 weighted MR images showed that the proposed method yielded a mean DSC of 89.7% +/- 4.2%, a MAD of 2.6 +/- 1.1 mm, a MAXD of 17.8 +/- 6.2 mm, and a VD of 11.6% +/- 5.9%, suggesting a good agreement with manual segmentations.

Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

NASA Astrophysics Data System (ADS)

Marquis, G. A.; Roy, A. G.

2012-02-01

This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.